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Archive for the ‘Nutrition’ Category


Nutrition: Articles of Note @PharmaceuticalIntelligence.com

Author and Curator: Larry H. Bernstein, MD, FCAP and Curator: Aviva Lev-Ari, PhD, RN

 

 

Nutrition and Wellbeing

 

Introduction 

Larry H. Bernstein, MD, FCAP

 

The chapters that follow are divided into three parts, but they are also a summary of 25 years of work with nutritional support research and involvement with nutritional support teams in Connecticut and New York, attendance and presentations at the American Association for Clinical Chemistry and the American Society for Parenteral and Enteral Nutrition, and long term collaborations with the surgeons Walter Pleban and Prof. Stanley Dudrick, and Prof. Yves Ingenbleek at the Laboratory of Nutrition, Department of Pharmacy, University Louis Pasteur, Strasbourg, Fr.   They are presented in the order: malnutrition in childhood; cancer, inflammation, and nutrition; and vegetarian diet and nutrition role in alternative medicines. These are not unrelated as they embrace the role of nutrition throughout the lifespan, the environmental impact of geo-ecological conditions on nutritional wellbeing and human development, and the impact of metabolism and metabolomics on the outcomes of human disease in relationship to severe inflammatory disorders, chronic disease, and cancer. Finally, the discussion emphasizes the negative impact of a vegan diet on long term health, and it reviews the importance of protein sources during phases of the life cycle.

Malnutrition in Childhood

 

Protein Energy Malnutrition and Early Child Development

Curator: Larry H. Bernstein, MD, FCAP

 

The Significant Burden of Childhood Malnutrition and Stunting

Curator: Larry H. Bernstein, MD, FCAP

 

Is Malnutrition the Cost of Civilization?

Curation: Larry H. Bernstein, MD, FCAP

 

Malnutrition in India, High Newborn Death Rate and Stunting of Children Age Under Five Years

Curator: Larry H Bernstein, MD, FCAP

 

Under Nutrition Early in Life may lead to Obesity

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Protein Malnutrition

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Cancer, Inflammation and Nutrition

 

A Second Look at the Transthyretin Nutrition Inflammatory Conundrum

Author and Curator: Larry H. Bernstein, MD, FACP

 

Cancer and Nutrition

Writer and Curator: Larry H. Bernstein, MD, FCAP

 

The history and creators of total parenteral nutrition

Curator: Larry H. Bernstein, MD, FCAP

 

Nutrition Plan

Curator: Larry H. Bernstein, MD, FCAP

 

Nutrition and Aging

Curator: Larry H Bernstein, MD, FCAP

 

Vegetarian Diet and Nutrition Role in Alternative Medicines

 

Plant-based Nutrition, Neutraceuticals and Alternative Medicine: Article Compilation the Journal PharmaceuticalIntelligence.com

Curator: Larry H. Bernstein, MD, FCAP

 

Metabolomics, Metabonomics and Functional Nutrition: the next step in nutritional metabolism and biotherapeutics

Reviewer and Curator: Larry H. Bernstein, MD, FCAP

 

2014 Epidemiology and Prevention, Nutrition, Physical Activity and Metabolism Conference: San Francisco, Ca. Conference Dates: San Francisco, CA 3/18-21, 2014

Reporter: Aviva Lev-Ari, PhD, RN

 

Metabolomics: its Applications in Food and Nutrition Research

Reporter and Curator: Sudipta Saha, Ph.D.

 

Summary

Larry H. Bernstein, MD, FCAP 

The interest in human malnutrition became a major healthcare issue in the 1980’s with the publication of several seminal papers on hospital malnutrition. However, the basis for protein-energy malnutrition that focused on the distinction between kwashiorkor and marasmus was first identified in seminal papers by Ingenbleek and others:

Ingenbleek Y. La malnutrition protein-calorique chez l’enfant en bas age. Repercussions sur la function thyroidienne et les protein vectrices du serum. PhD Thesis. Acco Press. 1997. Univ Louvain.

Ingenbleek Y, Carpentier YA. A prognostic inflammatory and nutrition index scoring critically ill patients. Internat J Vit Nutr Res 1985; 55:91-101.

Ingenbleek Y, Young VR. Transthyretin (prealbumin) in health and disease. Nutritional implications. Ann Rev Nutr 1994; 14:495-533.

Ingenbleek Y, Hardillier E, Jung L. Subclinical protein malnutrition is a determinant of hyperhomocysteinemia. Nutrition 2002; 18:40-46.

It was these early papers that transfixed my attention, and drove me to establish early the transthyretin test by immunodiffusion and later by automated immunoassay at Bridgeport Hospital.

Among the important studies often referred to with respect to hospital malnutrition are:

  1. Hill GL, Blackett RL, Pickford I, Burkinshaw L, Young GA, Warren JV. Malnutrition in surgical patients: An unrecognised problem. Lancet.1977; 310:689–692. [PubMed]
  2. Bistrian BR, Blackburn GL, Vitale J, Cochrane D, Naylor J. Prevalence of malnutrition in general medical patients. JAMA. 1976; 235:1567–1570. [PubMed]
  3. Butterworth CE. The skeleton in the hospital closet. Nutrition Today.1974; 9:4–8.
  4. Buzby GP, Mullen JL, Matthews DC, Hobbs CL, Rosato EF. Prognostic nutritional index in gastrointestinal surgery. Am. J. Surg. 1980; 139:160–167.[PubMed]
  5. Dempsey DT, Mullen JL, Buzby GP. The link between nutritional status and clinical outcomes: can nutritional intervention modify it? Am. J. Clin. Nutr. 1988; 47:352–356. [PubMed]
  6. Detsky AS, Mclaughlin JR, Baker JP, Johnston N, Whittaker S, Mendleson RA, Jeejeebhoy KN. What is subjective global assessment of nutritional status? JPEN J Parenter Enteral Nutr. 1987; 11:8–13. [PubMed]
  7. Scrimshaw NS, DanGiovanni JP. Synergism of nutrition, infection and immunity, an overview. J. Nutr. 1997; 133:S316–S321.
  8. Chandra RK. Nutrition and the immune system: an introduction. Am. J. Clin. Nutr. 1997; 66:460S–463S. [PubMed]
  9. Hill GL. Body composition reserach: Implications for the practice of clinical nutrition. JPEN J. Parenter. Enteral Nutr. 1992; 16:197. [PubMed]
  10. Smith PE, Smith AE. High-quality nutritional interventions reduce costs.Healthc. Financ. Manage. 1997; 5:66–69. [PubMed]
  11. Gallagher-Allred CR, Voss AC, Finn SC, McCamish MA. Malnutrition and clinical outcomes. J. Am. Diet. Assoc. 1996; 96:361–366. [PubMed]
  12. Ferguson M. Uncovering the skeleton in the hoapital closet. What next? Aust. J. Nutr. Diet. 2001; 58:83–84.
  13. Waitzberg DL, Caiaffa WT, Correia MITD. Hospital malnutrition: The Brazilian national survey (IBRANUTRI): a study of 4000 patients. Nutrition.2001; 17:573–580. [PubMed]

The work on hospital (and nursing home) treatment of malnutrition described in this series led to established standards. It first requires identifying a patient at malnutrition risk to be identified via either screening or assessment. This needs to be done on admission, and it has been made mandatory by health care accrediting bodies. In order to achieve this, dietitians need to have the confidence and knowledge to detect malnutrition, which is ideally done using a validated assessment for patient outcomes and financial benefits to be realized.

There is a worldwide relationship between ecological conditions, religious practices, soil conditions, availability of animal food sources, and altitude and river flows has not received the attention that evidence requires. We have seen that the emphasis on the Hindu tradition of not eating beef or having dairy is possibly problematic in the Ganges River basin. There may be other meat sources, but it is questionable that sufficient animal protein is available for the large population. The additional problem of water pollution is an aggravating situation. However, it is this region that is one of the most affected by stunting of children. We have a situation here and in other poor societies where veganism is present, and there is also voluntary veganism in western societies. This is not a practice that leads to any beneficial effect, and it has been shown to lead to a hyperhomocystenemia with the associated risk of arterial vascular disease. For those who voluntarily choose veganism, this is an unexpected result.

Met is implicated in a large spectrum of metabolic and enzyme activities and participates in the conformation of a large number of molecules of survival importance. Due to the fact that plant products are relatively Met-deficient, vegan subjects are more exposed than omnivorous to develop hyperhomocysteinemia – related disorders. Dietary protein restriction may promote supranormal Hcy concentrations which appears as the dark side of adaptive attempts developed by the malnourished and/or stressed body to preserve Met homeostasis.  Summing up, we assume that the low TTR concentrations reported in the blood and CSF of AD or MID patients result in impairment of their normal scavenging capacity and in the excessive accumulation of Hcy in body fluids, hence causing direct harmful damage to the brain and cardiac vasculature.

The content of these discussions has also included nutrition and cancer. This is perhaps least well understood. Reasons for such an association may well include chronic exposure to radiation damage, or persistent focal chronic inflammatory conditions. These would result in a cirumferential and repeated cycle of injury and repair combined with an underlying hypoxia. I have already established a fundamental relationship between inflammation, the cytokine storm, the decreased hepatic synthesis of essential plasma proteins, such as, albumin, transferrin, retinol-binding protein, and transthyretin, and the surge of steroid hormones. This results in an imbalance in the protein and free protein equilibrium of essential vitamins, the retinoids, and other circulating ligands transported. This is discussed in the ‘nutrition-inflammatory conundrum”. As stated, whatever the nutritional status and the disease condition, the actual transthyretin (TTR) plasma level is determined by opposing influences between anabolic and catabolic alterations. Rising TTR values indicate that synthetic processes prevail over tissue breakdown with a nitrogen balance (NB) turning positive as a result of efficient nutritional support and / or anti-inflammatory therapy. Declining TTR values are associated with an effect of maladjusted dietetic management and / or further worsening of the morbid condition.

Inflammatory disorders of any cause are initiated by activated leukocytes releasing a shower of cytokines working as autocrine, paracrine and endocrine molecules. Cytokines regulate the overproduction of acute-phase proteins (APPs), notably that of CRP, 1-acid glycoprotein (AGP), fibrinogen, haptoglobin, 1-antitrypsin and antichymotrypsin. APPs contribute in several ways to defense and repair mechanisms, being characterized by proper kinetic and functional properties. Interleukin-6 (IL-6) is regarded as a key mediator governing both the acute and chronic inflammatory processes, as documented by data recorded on burn, sepsis and AIDS patients. IL-6-NF possesses a high degree of homology with C/EBP-NF1 and competes for the same DNA response element of the IL-6 gene. IL-6-NF is not expressed under normal circumstances, explaining why APP concentrations are kept at baseline levels. In stressful conditions, IL-6-NF causes a dramatic surge in APP values with a concomitant suppressed synthesis of TTR.

Inadequate nutritional management, multiple injuries, occurrence of severe sepsis and metabolic complications result in persistent proteolysis and subnormal TTR concentrations. The evolutionary patterns of urinary N output and of TTR thus appear as mirror images of each other, which supports the view that TTR might well reflect the depletion of TBN in both acute and chronic disease processes. Even in the most complex stressful conditions, the synthesis of visceral proteins is submitted to opposing anabolic or catabolic influences yielding ultimately TTR as an end-product reflecting the prevailing tendency. Whatever the nutritional and/or inflammatory causal factors, the actual TTR plasma level and its course in process of time indicates the exhaustion or restoration of the body N resources, hence its likely (in)ability to assume defense and repair mechanisms.

In westernized societies, elderly persons constitute a growing population group. A substantial proportion of them may develop a syndrome of frailty characterized by weight loss, clumsy gait, impaired memory and sensorial aptitudes, poor physical, mental and social activities, depressive trends. Hallmarks of frailty combine progressive depletion of both structural and metabolic N compartments. Sarcopenia and limitation of muscle strength are naturally involutive events of normal ageing which may nevertheless be accelerated by cytokine-induced underlying inflammatory disorders. Depletion of visceral resources is substantiated by the shrinking of FFM and its partial replacement by FM, mainly in abdominal organs, and by the down-regulation of indices of growth and protein status. Due to reduced tissue reserves and diminished efficiency of immune and repair mechanisms, any stressful condition affecting old age may trigger more severe clinical impact whereas healing processes require longer duration with erratical setbacks. As a result, protein malnutrition is a common finding in most elderly patients with significantly increased morbidity and mortality rates.

TTR has proved to be a useful marker of nutritional alterations with prognostic implications in large bowel cancer, bronchopulmonary carcinoid tumor, ovarian carcinoma and squamous carcinoma of bladder. Many oncologists have observed a rapid TTR fall 2 or 3 months prior to the patient’s death. In cancer patients submitted to surgical intervention, most postoperative complications occurred in subjects with preoperative TTR  180 mg/L. Two independent studies came to the same conclusion that a TTR threshold of 100 mg/L is indicative of extremely weak survival likelihood and that these terminally ill patients better deserve palliative care rather than aggressive therapeutic strategies.

Thyroid hormones and retinoids indeed function in concert through the mediation of common heterodimeric motifs bound to DNA response elements. The data also imply that the provision of thyroid molecules within the CSF works as a relatively stable secretory process, poorly sensitive to extracerebral influences as opposed to the delivery of retinoid molecules whose plasma concentrations are highly dependent on nutritional and/or inflammatory alterations. This last statement is documented by mice experiments and clinical investigations showing that the level of TTR production by the liver operates as a limiting factor for retinol transport. Defective TTR synthesis determines the occurrence of secondary hyporetinolemia which nevertheless results from entirely different kinetic mechanisms in the two quoted studies.

Points to consider:

Protein energy malnutrition has an unlikely causal relationship to carcinogenesis. Perhaps the opposite is true. However, cancer has a relationship to protein energy malnutrition without any doubt. PEM is the consequence of cachexia, whether caused by dietary insufficiency, inflammatory or cancer.

Protein energy malnutrition leads to hyperhomocysteinemia, and by that means, the relationship of dietary insufficiency of methionine has a relationship to heart disease. This is the significant link between veganism and cardiovascular disease, whether voluntary or by unavailability of adequate source.

The last portion of these chapters deals with metabolomics and functional nutrition. This is an emerging and important area of academic interest. There is a significant relationship between these emerging studies and pathways to understanding natural products medicinal chemistry.

 

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Inflammatory Disorders: Articles published @ pharmaceuticalintelligence.com

Curators: Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

This is a compilation of articles on Inflammatory Disorders that were published 

@ pharmaceuticalintelligence.com, since 4/2012 to date

There are published works that have not been included.  However, there is a substantial amount of material in the following categories:

  1. The systemic inflammatory response
    https://pharmaceuticalintelligence.com/2014/11/08/introduction-to-impairments-in-pathological-states-endocrine-disorders-stress-hypermetabolism-cancer/
    https://pharmaceuticalintelligence.com/2014/11/09/summary-and-perspectives-impairments-in-pathological-states-endocrine-disorders-stress-hypermetabolism-cancer/
    https://pharmaceuticalintelligence.com/2015/12/19/neutrophil-serine-proteases-in-disease-and-therapeutic-considerations/
    https://pharmaceuticalintelligence.com/2014/03/21/what-is-the-key-method-to-harness-inflammation-to-close-the-doors-for-many-complex-diseases/
    https://pharmaceuticalintelligence.com/2012/08/20/therapeutic-targets-for-diabetes-and-related-metabolic-disorders/
    https://pharmaceuticalintelligence.com/2012/12/03/a-second-look-at-the-transthyretin-nutrition-inflammatory-conundrum/
    https://pharmaceuticalintelligence.com/2012/07/08/zebrafish-provide-insights-into-causes-and-treatment-of-human-diseases/
    https://pharmaceuticalintelligence.com/2016/01/25/ibd-immunomodulatory-effect-of-retinoic-acid-il-23il-17a-axis-correlates-with-the-nitric-oxide-pathway/
    https://pharmaceuticalintelligence.com/2015/11/29/role-of-inflammation-in-disease/
    https://pharmaceuticalintelligence.com/2013/03/06/can-resolvins-suppress-acute-lung-injury/
    https://pharmaceuticalintelligence.com/2015/02/26/acute-lung-injury/
  2. sepsis
    https://pharmaceuticalintelligence.com/2012/10/20/nitric-oxide-and-sepsis-hemodynamic-collapse-and-the-search-for-therapeutic-options/
  3. vasculitis
    https://pharmaceuticalintelligence.com/2015/02/26/acute-lung-injury/
    https://pharmaceuticalintelligence.com/2012/11/26/the-molecular-biology-of-renal-disorders/
    https://pharmaceuticalintelligence.com/2012/11/20/the-potential-for-nitric-oxide-donors-in-renal-function-disorders/
  4. neurodegenerative disease
    https://pharmaceuticalintelligence.com/2013/02/27/ustekinumab-new-drug-therapy-for-cognitive-decline-resulting-from-neuroinflammatory-cytokine-signaling-and-alzheimers-disease/
    https://pharmaceuticalintelligence.com/2016/01/26/amyloid-and-alzheimers-disease/
    https://pharmaceuticalintelligence.com/2016/02/15/alzheimers-disease-tau-art-thou-or-amyloid/
    https://pharmaceuticalintelligence.com/2016/01/26/beyond-tau-and-amyloid/
    https://pharmaceuticalintelligence.com/2015/12/10/remyelination-of-axon-requires-gli1-inhibition/
    https://pharmaceuticalintelligence.com/2015/11/28/neurovascular-pathways-to-neurodegeneration/
    https://pharmaceuticalintelligence.com/2015/11/13/new-alzheimers-protein-aicd-2/
    https://pharmaceuticalintelligence.com/2015/10/31/impairment-of-cognitive-function-and-neurogenesis/
    https://pharmaceuticalintelligence.com/2014/05/06/bwh-researchers-genetic-variations-can-influence-immune-cell-function-risk-factors-for-alzheimers-diseasedm-and-ms-later-in-life/
  5. cancer immunology
    https://pharmaceuticalintelligence.com/2013/04/12/innovations-in-tumor-immunology/
    https://pharmaceuticalintelligence.com/2016/01/09/signaling-of-immune-response-in-colon-cancer/
    https://pharmaceuticalintelligence.com/2015/05/12/vaccines-small-peptides-aptamers-and-immunotherapy-9/
    https://pharmaceuticalintelligence.com/2015/01/30/viruses-vaccines-and-immunotherapy/
    https://pharmaceuticalintelligence.com/2015/10/20/gene-expression-and-adaptive-immune-resistance-mechanisms-in-lymphoma/
    https://pharmaceuticalintelligence.com/2013/08/04/the-delicate-connection-ido-indolamine-2-3-dehydrogenase-and-immunology/
  6. autoimmune diseases: rheumatoid arthritis, colitis, ileitis, …
    https://pharmaceuticalintelligence.com/2016/02/11/intestinal-inflammatory-pharmaceutics/
    https://pharmaceuticalintelligence.com/2016/01/07/two-new-drugs-for-inflammatory-bowel-syndrome-are-giving-patients-hope/
    https://pharmaceuticalintelligence.com/2015/12/16/contribution-to-inflammatory-bowel-disease-ibd-of-bacterial-overgrowth-in-gut-on-a-chip/
    https://pharmaceuticalintelligence.com/2016/02/13/cytokines-in-ibd/
    https://pharmaceuticalintelligence.com/2016/01/23/autoimmune-inflammtory-bowl-diseases-crohns-disease-ulcerative-colitis-potential-roles-for-modulation-of-interleukins-17-and-23-signaling-for-therapeutics/
    https://pharmaceuticalintelligence.com/2014/10/14/autoimmune-disease-single-gene-eliminates-the-immune-protein-isg15-resulting-in-inability-to-resolve-inflammation-and-fight-infections-discovery-rockefeller-university/
    https://pharmaceuticalintelligence.com/2015/03/01/diarrheas-bacterial-and-nonbacterial/
    https://pharmaceuticalintelligence.com/2016/02/11/intestinal-inflammatory-pharmaceutics/
    https://pharmaceuticalintelligence.com/2014/01/28/biologics-for-autoimmune-diseases-cambridge-healthtech-institutes-inaugural-may-5-6-2014-seaport-world-trade-center-boston-ma/
    https://pharmaceuticalintelligence.com/2015/11/19/rheumatoid-arthritis-update/
    https://pharmaceuticalintelligence.com/2013/08/04/the-delicate-connection-ido-indolamine-2-3-dehydrogenase-and-immunology/
    https://pharmaceuticalintelligence.com/2013/07/31/confined-indolamine-2-3-dehydrogenase-controls-the-hemostasis-of-immune-responses-for-good-and-bad/
    https://pharmaceuticalintelligence.com/2012/09/13/tofacitinib-an-oral-janus-kinase-inhibitor-in-active-ulcerative-colitis/
    https://pharmaceuticalintelligence.com/2013/03/05/approach-to-controlling-pathogenic-inflammation-in-arthritis/
    https://pharmaceuticalintelligence.com/2013/03/05/rheumatoid-arthritis-risk/
    https://pharmaceuticalintelligence.com/2012/07/08/the-mechanism-of-action-of-the-drug-acthar-for-systemic-lupus-erythematosus-sle/
  7. T cells in immunity
    https://pharmaceuticalintelligence.com/2015/09/07/t-cell-mediated-immune-responses-signaling-pathways-activated-by-tlrs/
    https://pharmaceuticalintelligence.com/2015/05/14/allogeneic-stem-cell-transplantation-9-2/
    https://pharmaceuticalintelligence.com/2015/02/19/graft-versus-host-disease/
    https://pharmaceuticalintelligence.com/2014/10/14/autoimmune-disease-single-gene-eliminates-the-immune-protein-isg15-resulting-in-inability-to-resolve-inflammation-and-fight-infections-discovery-rockefeller-university/
    https://pharmaceuticalintelligence.com/2014/05/27/immunity-and-host-defense-a-bibliography-of-research-technion/
    https://pharmaceuticalintelligence.com/2013/08/04/the-delicate-connection-ido-indolamine-2-3-dehydrogenase-and-immunology/
    https://pharmaceuticalintelligence.com/2013/07/31/confined-indolamine-2-3-dehydrogenase-controls-the-hemostasis-of-immune-responses-for-good-and-bad/
    https://pharmaceuticalintelligence.com/2013/04/14/immune-regulation-news/

Proteomics, metabolomics and diabetes

https://pharmaceuticalintelligence.com/2015/11/16/reducing-obesity-related-inflammation/

https://pharmaceuticalintelligence.com/2015/10/25/the-relationship-of-stress-hypermetabolism-to-essential-protein-needs/

https://pharmaceuticalintelligence.com/2015/10/24/the-relationship-of-s-amino-acids-to-marasmic-and-kwashiorkor-pem/

https://pharmaceuticalintelligence.com/2015/10/24/the-significant-burden-of-childhood-malnutrition-and-stunting/

https://pharmaceuticalintelligence.com/2015/04/14/protein-binding-protein-protein-interactions-therapeutic-implications-7-3/

https://pharmaceuticalintelligence.com/2015/03/07/transthyretin-and-the-stressful-condition/

https://pharmaceuticalintelligence.com/2015/02/13/neural-activity-regulating-endocrine-response/

https://pharmaceuticalintelligence.com/2015/01/31/proteomics/

https://pharmaceuticalintelligence.com/2015/01/17/proteins-an-evolutionary-record-of-diversity-and-adaptation/

https://pharmaceuticalintelligence.com/2014/11/01/summary-of-signaling-and-signaling-pathways/

https://pharmaceuticalintelligence.com/2014/10/31/complex-models-of-signaling-therapeutic-implications/

https://pharmaceuticalintelligence.com/2014/10/24/diabetes-mellitus/

https://pharmaceuticalintelligence.com/2014/10/16/metabolomics-summary-and-perspective/

https://pharmaceuticalintelligence.com/2014/10/14/metabolic-reactions-need-just-enough/

https://pharmaceuticalintelligence.com/2014/11/03/introduction-to-protein-synthesis-and-degradation/

https://pharmaceuticalintelligence.com/2015/09/25/proceedings-of-the-nyas/

https://pharmaceuticalintelligence.com/2014/10/31/complex-models-of-signaling-therapeutic-implications/

https://pharmaceuticalintelligence.com/2014/03/21/what-is-the-key-method-to-harness-inflammation-to-close-the-doors-for-many-complex-diseases/

https://pharmaceuticalintelligence.com/2013/03/05/irf-1-deficiency-skews-the-differentiation-of-dendritic-cells/

https://pharmaceuticalintelligence.com/2012/11/26/new-insights-on-no-donors/

https://pharmaceuticalintelligence.com/2012/11/20/the-potential-for-nitric-oxide-donors-in-renal-function-disorders/

 

 

 

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A Reconstructed View of Personalized Medicine

Author: Larry H. Bernstein, MD, FCAP

 

There has always been Personalized Medicine if you consider the time a physician spends with a patient, which has dwindled. But the current recognition of personalized medicine refers to breakthrough advances in technological innovation in diagnostics and treatment that differentiates subclasses within diagnoses that are amenable to relapse eluding therapies.  There are just a few highlights to consider:

  1. We live in a world with other living beings that are adapting to a changing environmental stresses.
  2. Nutritional resources that have been available and made plentiful over generations are not abundant in some climates.
  3. Despite the huge impact that genomics has had on biological progress over the last century, there is a huge contribution not to be overlooked in epigenetics, metabolomics, and pathways analysis.

A Reconstructed View of Personalized Medicine

There has been much interest in ‘junk DNA’, non-coding areas of our DNA are far from being without function. DNA has two basic categories of nitrogenous bases: the purines (adenine [A] and guanine [G]), and the pyrimidines (cytosine [C], thymine [T], and  no uracil [U]),  while RNA contains only A, G, C, and U (no T).  The Watson-Crick proposal set the path of molecular biology for decades into the 21st century, culminating in the Human Genome Project.

There is no uncertainty about the importance of “Junk DNA”.  It is both an evolutionary remnant, and it has a role in cell regulation.  Further, the role of histones in their relationship the oligonucleotide sequences is not understood.  We now have a large output of research on noncoding RNA, including siRNA, miRNA, and others with roles other than transcription. This requires major revision of our model of cell regulatory processes.  The classic model is solely transcriptional.

  • DNA-> RNA-> Amino Acid in a protein.

Redrawn we have

  • DNA-> RNA-> DNA and
  • DNA->RNA-> protein-> DNA.

Neverthess, there were unrelated discoveries that took on huge importance.  For example, since the 1920s, the work of Warburg and Meyerhoff, followed by that of Krebs, Kaplan, Chance, and others built a solid foundation in the knowledge of enzymes, coenzymes, adenine and pyridine nucleotides, and metabolic pathways, not to mention the importance of Fe3+, Cu2+, Zn2+, and other metal cofactors.  Of huge importance was the work of Jacob, Monod and Changeux, and the effects of cooperativity in allosteric systems and of repulsion in tertiary structure of proteins related to hydrophobic and hydrophilic interactions, which involves the effect of one ligand on the binding or catalysis of another,  demonstrated by the end-product inhibition of the enzyme, L-threonine deaminase (Changeux 1961), L-isoleucine, which differs sterically from the reactant, L-threonine whereby the former could inhibit the enzyme without competing with the latter. The current view based on a variety of measurements (e.g., NMR, FRET, and single molecule studies) is a ‘‘dynamic’’ proposal by Cooper and Dryden (1984) that the distribution around the average structure changes in allostery affects the subsequent (binding) affinity at a distant site.

What else do we have to consider?  The measurement of free radicals has increased awareness of radical-induced impairment of the oxidative/antioxidative balance, essential for an understanding of disease progression.  Metal-mediated formation of free radicals causes various modifications to DNA bases, enhanced lipid peroxidation, and altered calcium and sulfhydryl homeostasis. Lipid peroxides, formed by the attack of radicals on polyunsaturated fatty acid residues of phospholipids, can further react with redox metals finally producing mutagenic and carcinogenic malondialdehyde, 4-hydroxynonenal and other exocyclic DNA adducts (etheno and/or propano adducts). The unifying factor in determining toxicity and carcinogenicity for all these metals is the generation of reactive oxygen and nitrogen species. Various studies have confirmed that metals activate signaling pathways and the carcinogenic effect of metals has been related to activation of mainly redox sensitive transcription factors, involving NF-kappaB, AP-1 and p53.

I have provided mechanisms explanatory for regulation of the cell that go beyond the classic model of metabolic pathways associated with the cytoplasm, mitochondria, endoplasmic reticulum, and lysosome, such as, the cell death pathways, expressed in apoptosis and repair.  Nevertheless, there is still a missing part of this discussion that considers the time and space interactions of the cell, cellular cytoskeleton and extracellular and intracellular substrate interactions in the immediate environment.

There is heterogeneity among cancer cells of expected identical type, which would be consistent with differences in phenotypic expression, aligned with epigenetics.  There is also heterogeneity in the immediate interstices between cancer cells.  Integration with genome-wide profiling data identified losses of specific genes on 4p14 and 5q13 that were enriched in grade 3 tumors with high microenvironmental diversity that also substratified patients into poor prognostic groups. In the case of breast cancer, there is interaction with estrogen , and we refer to an androgen-unresponsive prostate cancer.

Finally,  the interaction between enzyme and substrates may be conditionally unidirectional in defining the activity within the cell.  The activity of the cell is dynamically interacting and at high rates of activity.  In a study of the pyruvate kinase (PK) reaction the catalytic activity of the PK reaction was reversed to the thermodynamically unfavorable direction in a muscle preparation by a specific inhibitor. Experiments found that in there were differences in the active form of pyruvate kinase that were clearly related to the environmental condition of the assay – glycolitic or glyconeogenic. The conformational changes indicated by differential regulatory response were used to present a dynamic conformational model functioning at the active site of the enzyme. In the model, the interaction of the enzyme active site with its substrates is described concluding that induced increase in the vibrational energy levels of the active site decreases the energetic barrier for substrate induced changes at the site. Another example is the inhibition of H4 lactate dehydrogenase, but not the M4, by high concentrations of pyruvate. An investigation of the inhibition revealed that a covalent bond was formed between the nicotinamide ring of the NAD+ and the enol form of pyruvate.  The isoenzymes of isocitrate dehydrogenase, IDH1 and IDH2 mutations occur in gliomas and in acute myeloid leukemias with normal karyotype. IDH1 and IDH2 mutations are remarkably specific to codons that encode conserved functionally important arginines in the active site of each enzyme. In this case, there is steric hindrance by Asp279 where the isocitrate substrate normally forms hydrogen bonds with Ser94.

Personalized medicine has been largely viewed from a lens of genomics.  But genomics is only the reading frame.  The living activities of cell processes are dynamic and occur at rapid rates.  We have to keep in mind that personalized in reference to genotype is not complete without reconciliation of phenotype, which is the reference to expressed differences in outcomes.

 

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Nuts and health in aging

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

 

Nut consumption and age-related disease

Giuseppe GrossoRamon Estruch

MATURITAS · OCT 2015     http://dx.doi.org/10.1016/j.maturitas.2015.10.014

Current knowledge on the effects of nut consumption on human health has rapidly increased in recent years and it now appears that nuts may play a role in the prevention of chronic age-related diseases. Frequent nut consumption has been associated with better metabolic status, decreased body weight as well as lower body weight gain over time and thus reduce the risk of obesity. The effect of nuts on glucose metabolism, blood lipids, and blood pressure are still controversial. However, significant decreased cardiovascular risk has been reported in a number of observational and clinical intervention studies. Thus, findings from cohort studies show that increased nut consumption is associated with a reduced risk of cardiovascular disease and mortality (especially that due to cardiovascular-related causes). Similarly, nut consumption has been also associated with reduced risk of certain cancers, such as colorectal, endometrial, and pancreatic neoplasms. Evidence regarding nut consumption and neurological or psychiatric disorders is scarce, but a number of studies suggest significant protective effects against depression, mild cognitive disorders and Alzheimer’s disease. The underlying mechanisms appear to include antioxidant and anti-inflammatory actions, particularly related to their mono- and polyunsaturated fatty acids (MUFA and PUFA, as well as vitamin and polyphenol content. MUFA have been demonstrated to improve pancreatic beta-cell function and regulation of postprandial glycemia and insulin sensitivity. PUFA may act on the central nervous system protecting neuronal and cell-signaling function and maintenance. The fiber and mineral content of nuts may also confer health benefits. Nuts therefore show promise as useful adjuvants to prevent, delay or ameliorate a number of chronic conditions in older people. Their association with decreased mortality suggests a potential in reducing disease burden, including cardiovascular disease, cancer, and cognitive impairments.

 

Global life expectancy has increased from 65 years in 1990 to about 71 years in 2013 [1]. As life expectancy has increased, the number of healthy years lost due to disability has also risen in most countries, consistent with greater morbidity [2]. Reduction of mortality rates in developed countries has been associated with a shift towards more chronic non-communicable diseases [1]. Cardiovascular diseases (CVDs) and related risk factors, such as hypertension, diabetes mellitus, hypercholesterolemia, and obesity are the top causes of death globally, accounting for nearly one-third of all deaths worldwide [3]. Equally, the estimated incidence, mortality, and disability- adjusted life-years (DALYs) for cancer rose to 14.9 million incident cancer cases, 8.2 million deaths, and 196.3 million DALYs, with the highest impact of prostate and breast cancer in men and women, respectively [4]. Depression is a leading cause of disability worldwide (in terms of total years lost due to disability), especially in high-income countries, increasing from 15th to 11th rank (37% increase) and accounting for 18% of total DALYs (almost 100 million DALYs) [5]. Overall, the global rise in chronic non-communicable diseases is congruent with a similar rise in the elderly population. The proportion of people over the age of 60 is growing faster than any other age group and is estimated to double from about 11% to 22% within the next 50 years [6]. Public health efforts are needed to face this epidemiological and demographic transition, both improving the healthcare systems, as well as assuring a better health in older people. Accordingly, a preventive approach is crucial to dealing with an ageing population to reduce the burden of chronic disease.

In this context, lifestyle behaviors have demonstrated the highest impact for older adults in preventing and controlling the morbidity and mortality due to non- communicable diseases [7]. Unhealthy behaviors, such as unbalanced dietary patterns, lack of physical activity and smoking, play a central role in increasing both cardiovascular and cancer risk [7]. Equally, social isolation and depression in later life may boost health decline and significantly contribute to mortality risk [8]. The role of diet in prevention of disability and death is a well-established factor, which has an even more important role in geriatric populations. Research has focused on the effect of both single foods and whole dietary patterns on a number of health outcomes, including mortality, cardiovascular disease (CVD), cancer and mental health disorders (such as cognitive decline and depression) [9-13]. Plantbased dietary patterns demonstrate the most convincing evidence in preventing chronic non-communicable diseases [14-17]. Among the main components (including fruit and vegetables, legumes and cereals), only lately has attention focused on foods such as nuts. Knowledge on the effect of nut consumption on human health has increased rapidly in recent years. The aim of this narrative review is to examine recent evidence regarding the role of nut consumption in preventing chronic disease in older people.

Tree nuts are dry fruits with an edible seed and a hard shell. The most popular tree nuts are almonds (Prunus amigdalis), hazelnuts (Corylus avellana), walnuts (Juglans regia), pistachios (Pistachia vera), cashews (Anacardium occidentale), pecans (Carya illinoiensis), pine nuts (Pinus pinea), macadamias (Macadamia integrifolia), Brazil nuts (Bertholletia excelsa), and chestnuts (Castanea sativa). When considering the “nut” group, researchers also include peanuts (Arachis hypogea), which technically are groundnuts. Nuts are nutrient dense foods, rich in proteins, fats (mainly unsaturated fatty acids), fiber, vitamins, minerals, as well as a number of phytochemicals, such as phytosterols and polyphenols [18]. Proteins account for about 10-25% of energy, including individual aminoacids, such as L-arginine, which is involved in the production of nitric oxide (NO), an endogenous vasodilatator [19].

The fatty acids composition of nuts involves saturated fats for 415% and unsaturated fatty acids for 30-60% of the content. Unsaturated fatty acids are different depending on the nut type, including monounsaturated fatty acids (MUFA, such as oleic acid in most of nuts, whereas polyunsaturated fatty acids (PUFA, such as alpha-linolenic acid) in pine nuts and walnuts [20]. Also fiber content is similar among most nut types (about 10%), although pine nuts and cashews hold the least content. Vitamins contained in nuts are group B vitamins, such as B6 (involved in many aspects of macronutrient metabolism) and folate (necessary for normal cellular function, DNA synthesis and metabolism, and homocysteine detoxification), as well as tocopherols, involved in anti-oxidant mechanisms [21]. Among minerals contained in vegetables, nuts have an optimal content in calcium, magnesium, and potassium, with an extremely low amount of sodium, which is implicated on a number of pathological conditions, such as bone demineralization, hypertension and insulin resistance[22]. Nuts are also rich in phytosterols, non-nutritive components of certain plant-foods that exert both structural (at cellular membrane phospholipids level) and hormonal (estrogen-like) activities [23]. Finally, nuts have been demonstrated to be a rich source of polyphenols, which account for a key role in their antioxidant and anti-inflammatory effects.

 

Metabolic disorders are mainly characterized by obesity, hypertension, dyslipidemia, and hyperglycemia/ hyperinsulinemia/type-2 diabetes, all of which act synergistically to increase morbidity and mortality of aging population.

Obesity Increasing high carbohydrate and fat food intake in the last decades has contributed significantly to the rise in metabolic disorders. Nuts are energy-dense foods that have been thought to be positively associated with increased body mass index (BMI). As calorie-dense foods, nuts may contain 160–200 calories per ounce. The recommendation from the American Heart  Association to consume 5 servings per week (with an average recommended serving size of 28 g) corresponds to a net increase of 800–1000 calories per week, which may cause weight gain. However, an inverse relation between the frequency of nut consumption and BMI has been observed in large cohort studies [24]. Pooling the baseline observations of BMI by category of nut consumption in 5 cohort studies found a significant decreasing trend in BMI values with increasing nut intake [24]. While the evidence regarding nut consumption and obesity is limited, findings so far are encouraging [25, 26]. When the association between nut consumption and body weight has been evaluated longitudinally over time, nut intake was associated with a slightly lower risk of weight gain and obesity [25]. In the Nurses’ Health Study II (NHS II), women who eat nuts ≥2 times per week had slightly less weight gain (5.04 kg) than did women who rarely ate nuts (5.55 kg) and marginally significant 23% lower risk of obesity after 9-year follow-up [25]. Further evaluation of the NHS II data and the Physicians’ Health Study (PHS) comprising a total of 120,877 US women and men and followed up to 20 years revealed that 4-y weight change was inversely associated with a 1-serving increment in the intake of nuts (20.26 kg) [27]. In the “Seguimiento Universidad de Navarra” (SUN) cohort study, a significant decreased weight change has been observed over a period of 6 years [26]. After adjustment for potential confounding factors the analysis was no longer significant, but overall no weight gain associated with >2 servings per week of nuts has been observed. Finally, when considering the role of the whole diet on body weight, a meta-analysis of 31 clinical trials led to the conclusion of a null effect of nut intake on body weight, BMI, and waist circumference [28].

Glucose metabolism and type-2 diabetes The association between nut consumption and risk of type-2 diabetes in prospective cohort studies is controversial [29-32]. A pooled analysis relied on the examination of five large cohorts, including the NHS, the Shanghai Women’s Health Study, the Iowa Women’s Health Study, and the PHS, and two European studies conducted in Spain (the PREDIMED trial) and Finland including a total of more than 230,000 participants and 13,000 cases, respectively. Consumption of 4 servings per week was associated with 13% reduced risk of type-2 diabetes without effect modification by age [29]. In contrast, other pooled analyses showed non-significant reduction of risk for increased intakes of nuts, underlying that the inverse association between the consumption of nuts and diabetes was attenuated after adjustment for confounding factors, including BMI [30]. However, results from experimental studies showed promising results. Thus, nut consumption has been demonstrated to exert beneficial metabolic effects due to their action on post-prandial glycemia an insulin sensitivity. A number of RCTs have demonstrated positive effects of nut consumption on post-prandial glycemia in healthy individuals [33-38]. Moreover, a meta-analysis of RCTs on the effects of nut intake on glycemic control in diabetic individuals including 12 trials and a total of 450 participants showed that diets with an emphasis on nuts (median dose = 56 g/d) significantly lowered HbA1c (Mean Difference [MD] : -0.07%; 95% confidence interval [CI]: -0.10, -0.03%; P = 0.0003) and fasting glucose (MD : -0.15 mmol/L; 95% CI: -0.27, -0.02 mmol/L; P = 0.03) compared with control diets [39]. No significant treatment effects were observed for fasting insulin and homeostatic model assessment (HOMA-IR), despite the direction of effect favoring diet regimens including nuts.

Blood lipids and hypertension Hypertension and dyslipidemia are major risk factors for CVD. Diet alone has a predominant role in blood pressure and plasma lipid homeostasis. One systematic review [40] and 3 pooled quantitative analyses of RCTs [41-43] evaluated the effects of nut consumption on lipid profiles. A general agreement was relevant on certain markers, as daily consumption of nuts (mean = 67 g/d) induced a pooled reduction of total cholesterol concentration (10.9 mg/dL [5.1% change]), low-density lipoprotein cholesterol concentration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of LDL-C to high-density lipoprotein cholesterol concentration (HDL-C) (0.22 [8.3% change]), and ratio of total cholesterol concentration to HDL-C (0.24 [5.6% change]) (P <0.001 for all) [42]. All meta-analyses showed no significant effects of nut (including walnut) consumption on HDL cholesterol or triglyceride concentrations in healthy individuals [41], although reduced plasma triglyceride levels were found in individuals with hypertriglyceridemia [42]. Interestingly, the effects of nut consumption were dose related, and different types of nuts had similar effects on blood lipid concentrations.

There is only limited evidence from observational studies to suggest that nuts have a protective role on blood pressure. A pooled analysis of prospective cohort studies on nut consumption and hypertension reported a decreased risk associated with increased intake of nuts [32]. Specifically, only a limited number of cohort studies have been conducted exploring the association between nut consumption and hypertension (n = 3), but overall reporting an 8% reduced risk of hypertension for individuals consuming >2 servings per week (Risk Ratio [RR] = 0.92, 95% CI: 0.87-0.97) compared with never/rare consumers, whereas consumption of nuts at one serving per week had similar risk estimates (RR = 0.97, 95% CI: 0.83, 1.13) [32]. These findings are consistent with results obtained in a pooled analysis of 21 experimental studies reporting the effect of consuming single or mixed nuts (in doses ranging from 30 to 100 g/d) on systolic (SBP) and diastolic blood pressure (DBP) [44]. A pooled analysis found a significant reduction in SBP in participants without type2 diabetes [MD: -1.29 mmHg; 95% CI: -2.35, -0.22; P = 0.02] and DBP (MD: -1.19; 95% CI: -2.35, -0.03; P = 0.04), whereas subgroup analyses of different nut types showed that pistachios, but not other nuts, significantly reduced SBP (MD: -1.82; 95% CI: -2.97, -0.67; P = 0.002) and SBP (MD: -0.80; 95% CI: -1.43, -0.17; P = 0.01) [44].

Nut consumption and CVD risk Clustering of metabolic risk factors occurs in most obese individuals, greatly increasing risk of CVD. The association between nut consumption and CVD incidence [29-31] and mortality [24] has been explored in several pooled analyses of prospective studies. The overall risk calculated for CVD on a total of 8,862 cases was reduced by 29% for individuals consuming 7 servings per week (RR = 0.71, 95% CI: 0.59, 0.85) [30]. A meta-analysis including 9 studies on coronary artery disease (CAD) including 179,885 individuals and 7,236 cases, reporting that 1-serving/day increment would reduce risk of CAD of about 20% (RR = 0.81, 95% CI: 0.72, 0.91) [31]. Similar risk estimates were calculated for ischemic heart disease (IHD), with a comprehensive reduced risk of about 25-30% associated with a daily intake of nuts [29, 30]. Findings from 4 prospective studies have been pooled to estimate the association between nut consumption and risk of stroke, and a non-significant/borderline reduced risk was found [29-31, 45]. CVD mortality was explored in a recent meta-analysis including a total of 354,933 participants, 44,636 cumulative incident deaths, and 3,746,534 cumulative person-years [24]. One serving of nuts per week and per day resulted in decreased risk of CVD mortality (RR = 0.93, 95% CI: 0.88, 0.99 and RR =0.61, 95% CI: 0.42, 0.91, respectively], primarily driven by decreased coronary artery disease (CAD) deaths rather than stroke deaths [24]. Overall, all pooled analyses demonstrated a significant association between nut consumption and cardiovascular health. However, it has been argued that nut consumption was consistently associated with healthier background characteristics reflecting overall healthier lifestyle choices that eventually lead to decreased CVD mortality risk.

Nut consumption and cancer risk Cancer is one of the leading causes of death in the elderly population. After the evaluation of the impact on cancer burden of food and nutrients, it has been concluded that up to one third of malignancies may be prevented by healthy lifestyle choices. Fruit and vegetable intake has been the focus of major attention, but studies on nut consumption and cancer are scarce. A recent metaanalysis pooled together findings of observational studies on cancer incidence, including a total of 16 cohort and 20 casecontrol studies comprising 30,708 cases, compared the highest category of nut consumption with the lowest category and found a lower risk of any cancer of 25% (RR = 0.85, 95% CI: 0.86, 0.95) [46]. When the analysis was conducted by cancer site, highest consumption of nuts was associated with decreased risk of colorectal (RR = 0.76, 95% CI: 0.61, 0.96), endometrial (RR = 0.58, 95% CI: 0.43, 0.79), and pancreatic cancer (RR = 0.71, 95% CI: 0.51, 0.99), with only one cohort study was conducted on the last [46]. The potential protective effects of nut consumption on cancer outcomes was supported also by pooled analysis of 3 cohort studies [comprising the PREDIMED, the NHS, the HPS, and the Health Professionals Follow-Up Study (HPFS) cohorts] showing a decreased risk of cancer death for individuals consuming 3-5 servings of nuts per week compared with never eaters (RR = 0.86, 95% CI: 0.75, 0.98) [24]. The analysis was recently updated by including results from the Netherlands Cohort Study reaching a total of 14,340 deaths out of 247,030 men and women observed, confirming previous results with no evidence of between-study heterogeneity (RR = 0.85, 95% CI: 0.77, 0.93) [47]. However, a dose- response relation showed the non-linearity of the association, suggesting that only moderate daily consumption up to 5 g reduced risk of cancer mortality, and extra increased intakes were associated with no further decreased risk.

Nut consumption and affective/cognitive disorders Age-related cognitive decline is one of the most detrimental health problems in older people. Cognitive decline is a paraphysiological process of aging, but timing and severity of onset has been demonstrated to be affected by modifiable lifestyle factors, including diet. In fact, the nature of the age- related conditions leading to a mild cognitive impairment (MCI) differs by inflammation-related chronic neurodegenerative diseases, such as dementia, Alzheimer’s disease, Parkinson’s disease and depression. Evidence restricted to nut consumption alone is scarce, but a number of studies have been conducted on dietary patterns including nuts as a major component. A pooled analysis synthesizing findings of studies examining the association between adherence to a traditional Mediterranean diet and risk of depression (n = 9), cognitive decline (n = 8), and Parkinson’s disease (n = 1) showed a reduction of risk of depression (RR = 0.68, 95% CI: 0.54, 0.86) and cognitive impairment (RR = 0.60, 95% CI: 0.43, 0.83) in individuals with increased dietary adherence [10].

The study that first found a decreased risk of Alzheimer’s disease in individuals highly adherent to the Mediterranean diet was conducted in over 2,000 individuals in the Washington/Hamilton Heights-Inwood Columbia Aging Project (WHICAP), a cohort of non-demented elders aged 65 and older living in a multi-ethnic community of Northern Manhattan in the US (Hazard Ratio [HR] = 0.91, 95% CI: 0.83, 0.98) [48]. These results have been replicated in further studies on the Mediterranean diet, however nut consumption was not documented [49, 50]. A number of observational studies also demonstrated a significant association between this dietary pattern and a range of other cognitive outcomes, including slower global cognitive decline [51]. However, evidence from experimental studies is limited to the PREDIMED trial, providing interesting insights on the association between the Mediterranean diet supplemented with mixed nuts and both depression and cognitive outcomes. Regarding depression, the nutritional intervention with a Mediterranean diet supplemented with nuts showed a lower risk of about 40% in participants with type-2 diabetes (RR = 0.59, 95% CI: 0.36, 0.98) compared with the control diet [52]. However the effect was not significant in the whole cohort overall [52]. Regarding cognitive outcomes after a mean follow-up of 4.1 years, findings from the same trial showed significant improvements in memory and global cognition tests for individuals allocated to the Mediterranean diet supplemented with nuts [adjusted differences: -0.09 (95% CI: -0.05, 0.23), P = 0.04 and -0.05 (95% CI: -0.27, 0.18), P = 0.04, respectively], compared to control group, showing that Mediterranean diet plus mixed nuts is associated with improved cognitive function [53].

 

Potential mechanisms of protection of nut consumption Despite the exact mechanisms by which nuts may ameliorate human health being largely unknown, new evidence has allowed us to start to better understand the protection of some high-fat, vegetable, energy-dense foods such as nuts. Non- communicable disease burden related with nutritional habits is mainly secondary to exaggerated intakes of refined sugars and saturated fats, such as processed and fast- foods. Nuts provide a number of nutrient and non-nutrient compounds and it is only recently that scientists have tried to examine their effects on metabolic pathways.

Metabolic and cardiovascular protection With special regard to body weight and their potential effects in decreasing the risk of obesity (or weight gain, in general), nuts may induce satiation (reduction in the total amount of food eaten in a single meal) and satiety (reduction in the frequency of meals) due to their content in fibers and proteins, which are associated with increased release of glucagon-like protein 1 (GLP-1) and cholecystokinin (CCK), gastrointestinal hormones with satiety effects [54, 55]. The content in fiber of nuts may also increase thermogenesis and resting energy expenditure, and reduce post- prandial changes of glucose, thus ameliorating inflammation and insulin resistance. Moreover, the specific content profile of MUFA and PUFA provides readily oxidized fats than saturated or trans fatty acids, leading to reduced fat accumulation [56, 57]. The beneficial effects of nuts toward glucose metabolism may be provided by their MUFA content that improves the efficiency of pancreatic beta-cell function by enhancing the secretion of GLP1, which in turn helps the regulation of postprandial glycemia and insulin sensitivity [58]. MUFA and PUFA are also able to reduce serum concentrations of the vasoconstrictor thromboxane 2, which might influence blood pressure regulation. Together with polyphenols and anti-oxidant vitamins, nuts may also ameliorate inflammatory status at the vascular level, reducing circulating levels of soluble cellular adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, which are released from the activated endothelium and circulating monocytes [59]. Moreover, nuts may improve vascular reactivity due to their content in L-arginine, which is a potent precursor of the endogenous vasodilator nitric oxide. Nuts content in microelements is characterized by a mixture that may exert a direct effect in modulating blood pressure, including low content of sodium and richness in magnesium, potassium and calcium, which may interact to beneficially influence blood pressure
Despite the exact mechanisms by which nuts may ameliorate human health being largely unknown, new evidence has allowed us to start to better understand the protection of some high-fat, vegetable, energy-dense foods such as nuts. Non- communicable disease burden related with nutritional habits is mainly secondary to exaggerated intakes of refined sugars and saturated fats, such as processed and fast- foods. Nuts provide a number of nutrient and non-nutrient compounds and it is only recently that scientists have tried to examine their effects on metabolic pathways.

Cancer protection The potential mechanisms of action of nuts that may intervene in the prevention of cancer have not been totally elucidated. Numerous hypotheses have been proposed on the basis of basic research exploring the antioxidant and anti-inflammatory compounds characterizing nuts [61]. Vitamin E can regulate cell differentiation and proliferation, whereas polyphenols (particularly flavonoids such as quercetin and stilbenes such as resveratrol) have been shown to inhibit chemically-induced carcinogenesis [62]. Polyphenols may regulate the inflammatory response and immunological activity by acting on the formation of the prostaglandins and pro-inflammatory cytokines, which may be an important mechanism involved in a number of cancers, including colorectal, gastric, cervical and pancreatic neoplasms [62]. Among other compounds contained in nuts, dietary fiber may exert protective effects toward certain cancers (including, but not limited to colorectal cancer) by the aforementioned metabolic effects as well as increasing the volume of feces and anaerobic fermentation, and reducing the length of intestinal transit. As a result, the intestinal mucosa is exposed to carcinogens for a reduced time and the carcinogens in the colon are diluted [62]. Finally, there is no specific pathway demonstrating the protective effect of PUFA intake against cancer, but their interference with cytokines and prostaglandin metabolism may inhibit a state of chronic inflammation that may increase cancer risk [63].

Cognitive aging and neuro-protection There is no universal mechanism of action for nuts with regard to age-related conditions. A number of systemic biological conditions, such as oxidative stress, inflammation, and reduced cerebral blood flow have been considered as key factors in the pathogenesis of both normal cognitive ageing and chronic neurodegenerative disease [64]. Nuts, alone or as part of healthy dietary patterns, may exert beneficial effects due to their richness in antioxidants, including vitamins, polyphenols and unsaturated fatty acids, that may be protective against the development of cognitive decline and depression [65, 66]. Both animal studies and experimental clinical trials demonstrated vascular benefits of nuts, including the aforementioned lowering of inflammatory markers and improved endothelial function, which all appear to contribute to improved cognitive function [67]. The antioxidant action may affect the physiology of the ageing brain directly, by protecting neuronal and cell-signaling function and maintenance. Moreover, certain compounds contained in nuts may directly interact with the physiology and functioning of the brain. For instance, walnuts are largely composed of PUFA, especially ALA, which have been suggested to induce structural change in brain areas associated with affective experience [66]. Moreover, PUFA have been associated with improved symptoms in depressed patients, suggesting an active role in the underlying pathophysiological mechanisms [68]. Thus, the mechanisms of action of nut consumption on age-related cognitive and depressive disorders are complex, involving direct effects on brain physiology at the neuronal and cellular level and indirect effects by influencing inflammation.

 

Summary From an epidemiological point of view, nut eaters have been associated with overall healthier lifestyle habits, such as increased physical activity, lower prevalence of smoking, and increased consumption of fruits and vegetables [24]. These variables represent strong confounding factors in determining the effects of nuts alone on human health and final conclusions cannot be drawn. Nevertheless, results from clinical trials are encouraging. Nuts show promise as useful adjuvants to prevent, delay or ameliorate a number of chronic conditions in older people.

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Obesity Pharmaceutics

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

Battling the Bulge

Weight-loss drugs that target newly characterized obesity-related receptors and pathways could finally offer truly effective fat control.

By Bob Grant | November 1, 2015

http://www.the-scientist.com//?articles.view/articleNo/44322/title/Battling-the-Bulge/

http://www.the-scientist.com/November2015/NovBioBiz2_640px.jpg

Several years ago, antiobesity drug development was not looking so hot. In 2007, Sanofi-Aventis failed to win US Food and Drug Administration (FDA) approval for rimonabant—a pill that successfully helped people shed pounds—because the drug carried risks of depression and suicidal thoughts. Then, in 2008, Merck pulled the plug on its Phase 3 trials of taranabant because it also engendered suicidal thoughts and neurological effects in some participants. And a decade before those late-stage disappointments, a couple of FDA-approved weight-loss drugs were making headlines for carrying dangerous side effects. In 1997, the FDA pulled the obesity medications fenfluramine (of the wildly popular fen-phen drug combination) and dexfenfluramine (Redux) off the market after research turned up evidence of heart valve damage in people taking the drugs.

By 2009, Big Pharma was backing out of the weight-loss market, with Merck and Pfizer abandoning their programs to develop drugs similar to rimonabant and taranabant, which block cannabinoid receptors in the brain. Although the antiobesity drug market was big—according to CDC estimates, about 35 percent of adults in the U.S. are obese—a blockbuster weight-loss pill that didn’t have serious side effects was proving elusive.

But a few firms, including several small biotechs, decided to stick with it. “Some of the prior experience with drugs on the market, like fen-phen and Redux, have likely led large pharma to view the therapeutic space with some conservatism,” says Preston Klassen, executive vice president and head of global development at Orexigen Therapeutics, a small, California-based firm. “And generally, when you have that situation, smaller companies will step into that void when the science makes sense.” And their perseverance is starting to pay off. After a years-long drought in approvals for antiobesity medications, in the past few years the FDA has approved four new drugs specifically for general obesity: Belviq and Qsymia in 2012, and Contrave and Saxenda in late 2014. Three of these four were developed by small companies whose success hinges on one or a few compounds aimed directly at treating general obesity.

The recent burst of antiobesity drug approvals reflects an evolving appreciation for the molecular intricacies of this multifaceted, chronic disease. Today’s antiobesity drugs—including the four recent approvals and several more in development—have traded the blunt cudgel of appetite suppression for more precise targeting of pathways known to play roles in obesity. “With our understanding of the complex biology of obesity and all of the different molecules and receptors involved in the process, we’re much better able to target those molecules and receptors,” says Arya Sharma, chair in obesity research and management at the University of Alberta in Canada. “These are very specific agents that are designed for very specific actions. There is renewed enthusiasm in this field.”

Looking to combos

In the mid-20th century, the FDA approved several weight-loss drugs, starting with the appetite suppressant desoxyephedrine (methamphetamine hydrochloride) in 1947. Like the other appetite-suppressing drugs the FDA later approved through the 1950s and ’60s, desoxyephedrine accomplished short-term weight loss, but the transient benefit did not justify the side effects of long-term use, such as addiction, psychosis, and violent behavior. In 1973, as the nation voiced concern about the overuse of amphetamines, the FDA decreed that all obesity drugs were approved only for short-term use. The most recently approved obesity drugs, on the other hand, all have the FDA’s okay for long-term weight management.

Three of the newly approved drugs, Contrave, Belviq, and Qsymia, also aim to suppress appetite, and like many previous weight-loss therapies, all do so by targeting the hypothalamus, the brain region thought to be the seat of appetite control. Although the precise mechanism of Belviq, which is manufactured by San Diego–based Arena Pharmaceuticals, is unknown, researchers think that the key is its activation of serotonin-binding 5-HT2C receptors in proopiomelanocortin (POMC) neurons in the hypothalamus. When activated, these neurons reduce appetite and increase energy expenditure, according to Orexigen’s Klassen. His company’s Contrave also activates POMC neurons in the hypothalamus, while at the same time inhibiting opioid receptors, which would otherwise work to shut down POMC neuron firing, in the brain’s mesolimbic reward pathway. Contrave achieves this one-two punch because it is a combination therapy, incorporating two different compounds into a single weight-loss pill.

“The concept of a silver or magic bullet whereby one drug meets all of the needs within the obesity space has thus far proven to be inadequate,” says Klassen. “Right now I think the predominant opinion is that combination therapy is an appropriate way to go.”

Vivus’s Qsymia is also a combination drug, composed of phentermine—the other half of fen-phen and an activator of a G protein–coupled receptor called TAAR1—and an extended-release form of topiramate, an anticonvulsant with weight-loss side effects. Novo Nordisk—one of the few Big Pharma firms that stayed in the obesity game as others fled—is also turning its attention to combo therapies, testing its pipeline of investigational weight-loss compounds with Saxenda, its recently approved medicine that mimics glucagon peptide-1 (GLP-1), an appetite and calorie-intake regulator in the brain. “You need to combine at least two molecules to get the optimum effect,” says Novo Nordisk executive vice president and chief scientific officer Mads Krogsgaard Thomsen. The company has five other weight-loss compounds in development, and “we’re actually combining Saxenda with all of these new molecules,” he adds.

The University of Alberta’s Sharma agrees that combination therapies are a smart approach for attacking the multilayered mechanisms at play in obesity. “You’re dealing with a system that is very complex and very redundant. When you block one, other molecules or other parallel systems kick in,” he says. “My prediction for the future is that in order to get good results, one will have to move toward combinations . . . of more-specific and more-novel agents.”

On the horizon

On the heels of the recent FDA approvals, several new compounds with novel mechanisms of action are making their way through the drug-development pipeline. While most antiobesity drugs to date have aimed to suppress appetite by targeting brain regions involved in feelings of hunger and satiety, Boston-based Zafgen (for which Sharma serves as a paid advisor) is going after methionine aminopeptidase 2 (MetAP2) receptors in the liver and adipose tissue. “We’ve been one of the first ones to show that there is a significant and major weight-regulation center that the body has that exists outside the hypothalamus,” says Zafgen chief medical officer Dennis Kim. “Our drug [beloranib] is tapping into that mechanism.”

 

Zafgen researchers are investigating beloranib’s mechanism of action in patients that became very obese after their hypothalamus was damaged or removed as a result of craniopharyngioma, a type of brain cancer. “In about half of these cases, patients wake up hungry after surgery and it’s unrelenting, and they become morbidly obese very rapidly,” Kim says. Because the hypothalamus is damaged or missing, antiobesity drugs that target this brain region are ineffective. But beloranib “works just as well in these patients compared to patients with intact hypothalamus,” Kim says. As a result, beloranib may work in isolation without the need to combine different compounds, he adds. “If you can target a nodal point that’s much more upstream of simple circuitry-controlled hunger in the hypothalamus, you have the potential to reset the entire system.”

Meanwhile, another Boston-based firm, Rhythm Pharmaceuticals, is conducting clinical trials on obese patients with rare genetic disorders that compromise the melanocortin-4 (MC4) pathway, known to be involved in body weight regulation. Rhythm’s setmelanotide (RM-493) is a first-in-class drug that activates the MC4 pathway. And several companies, including the Japanese pharma firm Shionogi, are developing compounds that block the receptor of a neurotransmitter called neuropeptide Y, which plays a role in appetite stimulation and meal initiation.

Other new antiobesity targets include cyclic nucleotides, second messengers in signaling cascades such as the 3′-5′-cyclic guanosine monophosphate pathway, which conveys feelings of satiety and ramps up thermogenesis; amylin, a peptide hormone that slows gastric emptying and promotes satiety; ghrelin, a gut hormone that stimulates food intake; and a handful of pathways that affect nutrient absorption and metabolism. As more of obesity’s molecular complexities are sorted out, even more new drug targets will present themselves.

“I think we are on the verge of understanding obesity and the mechanisms underlying obesity,” says Novo Nordisk’s Thomsen. “That means that there is going to be a lot of good news for obesity going forward.”

 

WEIGHT-LOSS DRUG APPROVAL

© ISTOCK.COM/QUISP65Getting a weight-loss treatment approved by the FDA is a little different than the regulatory path taken by other drugs. To earn approval, companies must demonstrate that their drugs afford at least a 5 percent reduction in body weight over a year. And after a therapy reaches the market, companies have to conduct more research, specifically, into the drugs’ safety. Contrave, for example, which was approved in September 2014, is currently subject to rigorous post-marketing surveillance concerning evidence that the drug may lead to suicidal thoughts and behaviors. Other recently approved antiobesity drugs are under similar surveillance regimens.

The FDA also requires companies to test some approved weight-loss drugs specifically for their cardiovascular side effects. “Serious safety concerns have arisen with several obesity drugs in the past, which have informed our approach to drug development,” FDA spokesperson Eric Pahon wrote in an email to The Scientist. “All drugs approved for chronic weight management since 2012 have either had a cardiovascular outcome trial (CVOT) underway at the time of approval or have been required to initiate a CVOT as a post-marketing requirement.”

This additional testing, however, may scare off some drug developers from entering the antiobesity arena, Vivus spokesperson Dana Shinbaum wrote in an email to The Scientist. “The hurdles remain high . . . [and] may discourage innovation in this area.”

But even with the significant regulatory hurdles, it’s tough to deny the potential that exists in the antiobesity drug market. “We view obesity as one of the few remaining untapped therapeutic areas within primary care,” says Preston Klassen of Orexigen Therapeutics. “We think it’s tremendously important from a medical perspective, and we think it’s been well documented that even small reductions in body weight have meaningful and sustained impact on improved health.”

 

 

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Nutrition Plan


Nutrition Plan

Curator: Larry H. Bernstein, MD, FCAP

 

This Is What A Perfect Day Of Eating Looks Like

Raise your hand if you wish a nutritionist would tell you exactly what to eat and when to look and feel great all day long. Yeah, we thought so—that’s why we tapped three experts who counsel real women on the simple secrets of smarter meal planning.
1) Have a meal or small snack every 3 to 4 hours. This fuels your metabolism and helps prevent binges and blood sugar crashes.2) Combine protein (meat, fish, beans, nuts, eggs, dairy) and fiber (whole grains, fruits, vegetables) at every meal. When eaten together, these foods take longer to digest than simpler carbohydrates, so you stay fuller, longer.3) Get up, move around, and drink water often. This daily meal plan has a wide range of calories (from about 1,550 to 2,100); if you’re active you can go toward the higher end of the range.

Finally, remember that even the “perfect day” isn’t perfect if you eat the same thing over and over again. Use the principles outlined here to mix and match your own delicious, healthy meals.

 

unfortunately most of our food stuff is nutrient void, the recommendations have been based on information from the 50’s . Read Hidden Hunger for validation . I have also been in agriculture for 40 years and have witnessed the change to corporate agriculture from quality to quantity . I can help aminos are the most important 75% of the human body dry weight , vitamins and minerals 1.5% . With age our bodies do not produce enough of endogenous aminos and exogenous are from the foods . They are heat sensitive ..

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Adenosine Receptor Agonist Increases Plasma Homocysteine

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

The Adenosine Receptor Agonist 5’-N-Ethylcarboxamide-Adenosine Increases Mouse Serum Total Homocysteine Levels, Which Is a Risk Factor for Cardiovascular Diseases

Spring Zhou Editor at Scientific Research Publishing

I would like to share this paper with you. Any comments on this article are welcome.

 

An increase in total homocysteine (Hcy) levels (protein-bound and free Hcy in the serum) has been identified as a risk factor for vascular diseases. Hcy is a product of the methionine cycle and is a precursor of glutathione in the transsulfuration pathway. The methionine cycle mainly occurs in the liver, with Hcy being exported out of the liver and subsequently bound to serum proteins. When the non-specific adenosine receptor agonist 5’-N-ethylcarboxamide-adenosine (NECA; 0.1 or 0.3 mg/kg body weight) was intraperitoneally administered to mice that had been fasted for 16 h, total Hcy levels in the serum significantly increased 1 h after its administration. The NECA treatment may have inhibited transsulfuration because glutathione levels were significantly decreased in the liver. After the intraperitoneal administration of a high dose of NECA (0.3 mg/kg body weight), elevations in total Hcy levels in the serum continued for up to 10 h. The mRNA expression of methionine metabolic enzymes in the liver was significantly reduced 6 h after the administration of NECA. NECA-induced elevations in total serum Hcy levels may be maintained in the long term through the attenuated expression of methionine metabolic enzymes.

 

Comments:

  1.  Is level of protein consumption a factor?
  2. Is reliance on plant food products a factor?
  3. What are the levels of transthyretin?
  4. Is there a concomitant decrease in vitamin A or vitamin D?

 

 

The Adenosine Receptor Agonist 5’-N-Ethylcarboxamide-Adenosine Increases Mouse Serum Total Homocysteine Levels, Which Is a Risk Factor for Cardiovascular Diseases

Shigeko Fujimoto Sakata*, Koichi Matsuda, Yoko Horikawa, Yasuto Sasaki     Faculty of Nutrition, Kobe Gakuin University, Kobe, Japan.

http://www.scirp.org/journal/PaperInformation.aspx    DOI: 10.4236/pp.2015.610048

Cite this paper

Sakata, S. , Matsuda, K. , Horikawa, Y. and Sasaki, Y. (2015) The Adenosine Receptor Agonist 5’-N-Ethylcarboxamide-Adenosine Increases Mouse Serum Total Homocysteine Levels, Which Is a Risk Factor for Cardiovascular Diseases. Pharmacology & Pharmacy, 6, 461-470. doi: 10.4236/pp.2015.610048.
An increase in total serum homocysteine levels (total Hcy: serum protein-bound and free Hcy) has been identified as a risk factor for cardiovascular disease [1] [2] and liver fibrosis [3]. The normal range of total Hcy in adults is typically 5 – 15 μM, with the mean level being approximately 10 μM [2]. Plasma Hcy concentrations were previously found to be strongly associated with the presence and number of small infarctions, or infarction of the putamen in elderly diabetic patients [4]. High levels of Hcy have been shown to induce endoplasmic reticulum (ER) stress and increase the production of reactive oxygen species (ROS) [5]. Hcy has strong reducibility and modifies disulfide bonds in proteins. Only 1% to 2% of Hcy occurs as thiol homocysteine in the serum; 75% of Hcy has been suggested to bind to proteins through disulfide bonds with protein cysteines [6]. Hcy is formed as an intermediary in methionine metabolism [7] [8]. Methionine metabolism mainly occurs in the livers of mammals. Methionine receives an adenosine group from ATP to become S-adenosylmethionine (AdoMet) in the methionine cycle. This reaction is catalyzed in the liver by liver-specific methionine adenosyltransferase I/III (MAT I/III), which is encoded by the methionine adenosyltransferase 1A (MAT1A) gene [9]. AdoMet then transfers its methyl group to a large number of compounds, a process that is catalyzed by various methyltransferases (e.g., glycine N-methyltransferase: GNMT; DNA methyltransferase; phosphatidylethanolamine N-methyl- transferase), to produce S-adenosylhomocysteine (AdoHcy). Hcy is formed from AdoHcy by AdoHcy hydrolase (SAHH). The reaction that generates Hcy from AdoHcy is reversible, and AdoHcy from Hcy is shown to be thermodynamically favored over the synthesis of Hcy [10]. A previous study reported that Hcy levels were very low in the liver [11]. This reaction then proceeds toward the synthesis of Hcy when the products (Hcy and adenosine) are removed by further metabolism [12]. Three enzymes metabolize Hcy, with the betaine-homocysteine S-methyltransferase (BHMT) and methionine synthase (MS) reactions both yielding methionine. A large proportion of Hcy in the liver is remethylated by BHMT [3]. The third enzyme, cystathionine β-synthase (CBS) catalyzes Hcy to cystathionine in the transsulfuration pathway. Previous studies of whole body methionine kinetics demonstrated that 62% of Hcy was converted to cystathionine during each cycle in males fed a basal diet, resulting in the production of glutathione (GSH), while 38% of Hcy was remethylated to methionine [13]. Hcy is located at an important regulatory branch point: remethylation to methionine; conversion to cystathionine; export from the cells.
A decrease in intracellular ATP levels, accompanied by the accumulation of 5’-AMP and subsequently adenosine, is known to follow ischemia. Adenosine levels in interstitial fluids were shown to increase 100 – 1000- fold from basal levels (10 – 300 nM) with ischemia [14]. Furthermore, adenosine levels in hepatocytes were increased by a hypoxic challenge, with excess amounts of adenosine being exported out of cells [14]. Adenosine levels were also found to increase 10-fold due to hypoxia, stress, and inflammation [15]. Adenosine has been shown to activate A1, A2a, and A3 receptors with EC50 values in the range of 0.2 – 0.7 μM, and also A2b receptors with an EC50 of 24 μM [16]. A1 and A3 receptors have been classified as adenylate cyclase inhibitory receptors, and A2a and A2b receptors as adenylate cyclase-activating receptors [17]. The activation of adenosine receptors accompanied by ischemia may increase total Hcy levels in the serum because hepatic ischemia is known to decrease the content of GSH and activity of MAT [18].
We previously reported that the non-specific adenosine receptor agonist 5’-N-ethylcarboxamide-adenosine (NECA) increased serum glucose levels and the expression of a glucogenic enzyme (glucose 6-phosphatase) in the liver [19] [20]. Based on the dose of NECA administered in these studies and plasma concentrations after the administration of other adenosine agonists [21], it was inferred that the serum NECA concentration was in the μM range and also that NECA activated adenosine A2b receptors. In the present study, we measured methionine metabolites, including Hcy, in NECA-treated mice in order to determine whether the activation of adenosine receptors increased total Hcy levels in the serum. The results obtained clearly demonstrated that NECA increased total Hcy levels in the serum.
Measurement of Methionine Metabolites AdoMet and AdoHcy levels in the liver were measured using an HPLC method [25] and total GSH in the liver was measured using a microtiter plate assay [26], as described previously [23]. Total Hcy and total cysteine levels (total Cys: free and protein-bound cysteine) in the serum were measured using an HPLC method [27]. Briefly, a mixture of 50 μL of serum, 25 μL of an internal standard, and 25 μL of phosphate-buffered saline (PBS, pH 7.4) was incubated with 10 μL of 100 mg/mL TCEP for 30 min at room temperature in order to reduce and release protein-bound thiols. After this incubation, 90 μL of 100 mg/mL trichloroacetic acid containing 1 mmol/L EDTA was added for deproteinization, centrifuged at 15,000 ×g for 10 min, and 50 μL of the supernatant was added to a tube containing 10 μL of 1.55 mol/L NaOH; 125 μL of 0.125 mol/L borate buffer containing 4 mmol/L EDTA, pH 9.5; and 50 μL of 1 mg/mL SBD-F in the borate buffer. The sample was then incubated for 60 min at 60˚C. HPLC was performed on a Waters M-600 pump equipped with a Waters 2475 Multi λ Fluorescence Detector (385 nm excitation, 515 nm emission). The separation of SBD-derivatized thiols was performed on a μ-BONDASPHERE C18 column (Waters, 5 μm, 100 A, 150 × 3.9 mm) with a 20-μL injection volume and 0.1 mol/L acetate buffer, pH 5.5, containing 30 ml/L methanol as the mobile phase at a flow rate of 1.0 mL/min and column temperature of 29˚C.
3.1. Effects of NECA on Total Hcy and Total Cys Levels in the Serum As shown in Table 1, serum total Hcy and total Cys levels significantly increased after 16 h of fasting. The administration of a low dose of NECA (NECA0.1 group) to mice fasted for 16 h resulted in higher serum total Hcy levels than those in the control group at 1 h (Experiment 1). Serum total Hcy levels were also significantly elevated at 3 h (Experiment 2), but were not significantly different from those in the control group at 6 h (Experiment 3). The administration of a high dose of NECA (NECA0.3 group) resulted in significantly higher serum total Hcy levels than those in the control group at 1 h, 3 h, 6 h, and 10 h (Experiments 4, 5, 6, and 7), gradually increasing Hcy levels to 19.7 μM. The effects of NECA on serum total Cys levels were the same as those on total Hcy levels.
Table 1. Effects of NECA on the content of total homocysteine and total cysteine in the serum.

3.2. Effects of NECA on Other Methionine Metabolite Levels in the Liver We previously reported that fasting for 16 h decreased AdoMet and GSH levels, and increased AdoHcy levels in the livers of mice [23]. In the present study, as shown in Table 2, the administration of a low dose of NECA (NECA0.1 group) to mice fasted for 16 h resulted in lower liver GSH levels than those in the control group at 1 h (Experiment 1). Liver GSH levels were also significantly lower at 3 h (Experiment 2), while GSH levels were not significantly different from those in the control group at 6 h (Experiment 3). The administration of a high dose of NECA (NECA0.3 group) resulted in liver GSH levels that were significantly lower than those in the control group at 1 h, 6 h, and 10 h (Experiments 4, 6, and 7). The effects of NECA on total Hcy levels in the serum and GSH levels in the liver were similar at each dose and time. Furthermore, the low and high doses of NECA both led to significantly higher AdoMet levels than those in the control group at 1 h (Experiments 1 and 4). AdoMet levels at 3 h, 6 h, and 10 h were not significantly different from those in the control group (Experiments 2, 3, 5, 6, and 7). AdoHcy levels were significantly lower in the NECA0.3 group than in the control group 6 h and 10 h after the administration of NECA (Experiments 6 and 7), while the administration of a low dose of NECA had less of an impact on AdoHcy levels.

Table 2. Effects of NECA on the content of methionine metabolites in the liver.

3.3. Effects of NECA on mRNA Expression of Methionine Cycle Enzymes in the Liver Figure 1 shows changes in the mRNA expression of methionine cycle enzymes in Experiments 4, 5, and 6. The expression of methionine cycle enzymes did not significantly change 1 h after the administration of NECA. The expression of MAT1A mRNA was significantly decreased in the liver 6 h after the NECA treatment, while that of MAT2A was increased. The changes observed in the expression of MAT in the present study were consistent with previous findings obtained in ischemic livers [18] or with liver regeneration [28]. The expression of GNMT, which eliminates excess AdoMet, was significantly decreased 6 h after the NECA treatment. The expression of CBS, which converts Hcy to cystathionine through the transsulfuration pathway, and BHMT, which converts Hcy to methionine, was also decreased at 6 h.

Figure 1 shows changes in the mRNA expression of methionine cycle enzymes in Experiments 4, 5, and 6. The expression of methionine cycle enzymes did not significantly change 1 h after the administration of NECA. The expression of MAT1A mRNA was significantly decreased in the liver 6 h after the NECA treatment, while that of MAT2A was increased. The changes observed in the expression of MAT in the present study were consistent with previous findings obtained in ischemic livers [18] or with liver regeneration [28]. The expression of GNMT, which eliminates excess AdoMet, was significantly decreased 6 h after the NECA treatment. The expression of CBS, which converts Hcy to cystathionine through the transsulfuration pathway, and BHMT, which converts Hcy to methionine, was also decreased at 6 h.
Figure 1. Effects of NECA on the mRNA expression of methionine cycle enzymes in the mouse liver. Northern hybridization was performed on the liver RNA of mice in experiments 4, 5, and 6. The mean ± SEM of the ratio of each enzyme mRNA to the level of the 18S rRNA signal is shown as an arbitrary unit. Unpaired Student’s t-tests were used to compare NECA- treated groups with the control groups. *p < 0.05, **p < 0.01: significantly different from each control.
4. Discussion In the present study, an increase in total Hcy levels and AdoMet levels, and decrease in GSH levels occurred 1 h after the NECA treatment. These results were not due to changes in the expression of methionine metabolic enzymes, which remained unchanged 1 h after the NECA treatment (Figure 1). The effects of NECA on methionine metabolism are summarized in Figure 2. No previous study has demonstrated that adenosine has the ability to directly affect CBS; however, the overproduction of carbon monoxide (CO), which is generated by heme oxygenase (HO), is found to inhibit transsulfuration [11]. CO has been shown to inhibit CBS activity and increase AdoMet concentrations [11]. Adenosine and NECA were previously reported to markedly induce HO in macrophages [29]. Hcy, which is a substrate of CBS, may be increased by NECA via the CO-induced inhibition of CBS, and GSH may be decreased by the CO-induced inhibition of transsulfuration. However, the mechanism by which NECA affects transsulfuration in the short term has not yet been elucidated.
Figure 2. Effects of NECA on the methionine metabolic pathway. MAT: methionine adenosyltransferase, GNMT: glycine N-methyltransferase, CBS: cystathionine β-synthase, BHMT: betaine-homocysteine S-methyltransferase, MS: methionine synthase (Map is based on Sakata SF 2005).
GSH was maintained at a low level for up to 10 h by the NECA0.3 treatment and transsulfuration may have been continuously inhibited by the NECA0.3 treatment. Total Hcy levels were also continuously increased for up to 10 h by the NECA0.3 treatment, and decreased AdoHcy levels were observed 6 h and 10 h after the NECA0.3 treatment. Long-term elevations in serum total Hcy levels by NECA may be maintained by attenuating the expression of methionine metabolic enzymes via the following mechanisms: The expression of methionine metabolic enzymes in the liver was reduced 6 h after the NECA0.3 treatment (Figure 1); the flow of the methionine cycle may have been decreased by changes in the expression of MAT (decreased liver-specific MAT1A expression and increased non-liver type MAT2A expression) because MATIII (Km for methionine: 215 μM – 7 mM) is the true liver-specific isoform responsible for methionine metabolism [30] and the generation rate of AdoMet by MATII (non-liver type enzyme) was modest with a low Km (80 μM for methionine) [31]; inhibition of the methyltransferases, BHMT [32] and GNMT [33], induces hyperhomocysteinemia; decreases in AdoHcy levels may be caused by reductions in methyltransferase levels. However, the mechanisms by which NECA continuously increased total Hcy levels have not yet been elucidated in detail. 5. Conclusion The present study confirmed that the non-specific adenosine receptor agonist NECA continuously increased total Hcy levels in the serum. The inhibition of adenosine receptors may decrease the risk of cardiovascular diseases because an increase in serum total Hcy levels is a known risk factor.

References

[1] Antoniades, C., Antonopoulos, A.S., Tousoulis, D., Marinou, K. and Stefanadis, C. (2009) Homocysteine and Coronary Atherosclerosis: from Folate Fortification to the Recent Clinical Trials. European Heart Journal, 30, 6-15.
http://dx.doi.org/10.1093/eurheartj/ehn515
[2] Refsum, H., Ueland, P.M., Nygard, O. and Vollset, S.E. (1998) Homocysteine and Cardiovascular Disease. Annual Review of Medicine, 49, 31-62.
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[3] Garcia-Tevijano, E.R., Berasain, C., Rodriguez, J.A., Corrales, F.J., Arias, R., Martin-Duce, A., Caballeria, J., Mato, J.M. and Avila, M.A. (2001) Hyperhomocysteinemia in Liver Cirrhosis: Mechanisms and Role in Vascular and Hepatic Fibrosis. Hypertension, 38, 1217-1221.
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[4] Araki, A., Ito, H., Majima, Y., Hosoi, T. and Orimo, H. (2003) Association between Plasma Homocysteine Concentrations and Asymptomatic Cerebral Infarction or Leukoaraiosis in Elderly Diabetic Patients. Geriatrics & Gerontology International, 3, 15-23.
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[5] Elanchezhian, R., Palsamy, P., Madson, C.J., Lynch, D.W. and Shinohara, T. (2012) Age-Related Cataracts: Homocysteine Coupled Endoplasmic Reticulum Stress and Suppression of Nrf2-Dependent Antioxidant Protection. Chemico-Biological Interactions, 200, 1-10.
http://dx.doi.org/10.1016/j.cbi.2012.08.017
[6] Mudd, S.H., Finkelstein, J.D., Refsum, H., Ueland, P.M., Malinow, M.R., Lentz, S.R., Jacobsen, D.W., Brattstrom, L., Wilcken, B., Wilcken, D.E., Blom, H.J., Stabler, S.P., Allen, R.H., Selhub, J. and Rosenberg, I.H. (2000) Homocysteine and Its Disulfide Derivatives: A Suggested Consensus Terminology. Arteriosclerosis Thrombosis and Vascular Biology, 20, 1704-1706.
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[7] Finkelstein, J.D. (1990) Methionine Metabolism in Mammals. The Journal of Nutritional Biochemistry, 1, 228-237.
http://dx.doi.org/10.1016/0955-2863(90)90070-2
[8] Stipanuk, M.H. (2004) Sulfur Amino Acid Metabolism: Pathways for Production and Removal of Homocysteine and Cysteine. Annual Review of Nutrition, 24, 539-577.
http://dx.doi.org/10.1146/annurev.nutr.24.012003.132418
[9] Chou, J.Y. (2000) Molecular Genetics of Hepatic Methionine Adenosyltransferase Deficiency. Pharmacology & Therapeutics, 85, 1-9.
http://dx.doi.org/10.1016/s0163-7258(99)00047-9
[10] De La Haba, G. and Cantoni, G.L. (1959) The Enzymatic Synthesis of S-Adenosyl-L-Homocysteine from Adenosine and Homocysteine. The Journal of Biological Chemistry, 234, 603-608.
http://www.jbc.org/content/234/3/603.short

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