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‘Lung-on-a-chip’

Posted in Bio Instrumentation in Experimental Life Sciences Research, Medical Devices R&D Investment, tagged alveolar, alveolar-capillary interface, Ang-1, angiopoietin-1, Biomedical Engineering, chip, edema, Harvard, IL-2, IL2, Interleukin-2, lung, Lung-on-a-chip, mechanical strain, microchannels, microfluid, microvascular, pulmonary edema, Wyss Institute on November 29, 2012| 6 Comments »

A revolutionary microchip-based human disease model for testing drugs

Reporter: Ritu Saxena, Ph.D.

Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, have developed lung-on-a-microfluid chip and shown that it mimic human lung function in response to Interluekin-2 (IL-2) and mechanical strain. Authors describe it as “a “lung-on-a-chip” that reconstituted the alveolar-capillary interface of the human lung and exposed it to physiological mechanical deformation and flow; in other words, it breathed rhythmically much like a living lung”.

The model was developed by Hu et al and reported earlier in the journal Science in 2010. The group has now been successful in demonstrating that lung-on-a-chip can act as a drug-testing model for pulmonary edema. Infact, Hu et al were able to predict the activity of a new drug, GSK2193874, for edema. Authors stated “These studies also led to identification of potential new therapeutics, including angiopoietin-1 (Ang-1) and a new transient receptor potential vanilloid 4 (TRPV4) ion channel inhibitor (GSK2193874), which might prevent this life-threatening toxicity of IL-2 in the future.” The findings have been published recently in the November 7 issue of Science Translational Medicine.

Research

To recreate lung on the microchip, the authors cultured two toes of human lung cells in parallel microchannels separated by a thin membrane. It was observed that the upper channel (alveolar) was filled with air, while the lower channel (microvascular) was filled with liquid. The observation was similar to what occurs in human lung. Breathing motion of the lung was mimicked on the chip by applying vacuum cyclically to the sides of the channels.

Mimicking pulmonary edema

Pulmonary edema is a condition characterized by the abnormal buildup of fluid in the air sacs of the lungs, which leads to shortness of breath. It is often caused when the heart is not able to pump blood to the body efficiently, it can back up into the veins that take blood through the lungs to the left side of the heart. As the pressure in these blood vessels increases, fluid is pushed into the air spaces (alveoli) in the lungs. This fluid reduces normal oxygen movement through the lungs. This and the increased pressure can lead to shortness of breath.

Hu and colleagues observed that when IL-2 was added to the microvascular channel, the fluid started to leak into the alveolar compartment of the chip. This process is a reproduction of what happens in edema. Further, adding cyclic mechanical strain along with IL-2 compromised the pulmonary barrier even further and leading to a threefold increase in leakage.

Drug-testing model

Once the authors established the pulmonary disease model on the microchip, they tested against a novel pharmacological agent, GSK2193874, which blocks certain ion channels activated by mechanical strain. This drug was able to inhibit leakage suggesting that it might be a viable treatment option for patients with pulmonary edema who are being mechanically ventilated. A major advantage of using this model is avoiding the use of animal models for research.

Future perspective

The lung-on-a-chip model developed by Hu et al could be used to test novel agents for pulmonary edema.

Editorial note on the article in Science translational medicine article states “The next step is to hook this lung up to other chip-based organs− heart, liver, pancreas, etc.−with the goal of one day being able to rapidly screen many drugs and conditions that could affect patient health.”

Source:

Journal articles

Hul D, et al. A Human Disease Model of Drug Toxicity−Induced Pulmonary Edema in aLung-on-a-Chip. Microdevice Sci Transl Med. 2012 Nov 7;4(159):159ra147.http://www.ncbi.nlm.nih.gov/pubmed/23136042

Hul D et al Reconstituting organ-level lung functions on a chip. Science. 2010 Jun 25;328(5986):1662-8. http://www.ncbi.nlm.nih.gov/pubmed/20576885

News brief

Video link to lung-on-a-chip http://wyss.harvard.edu/viewpage/240/

Sciencedaily report, November 7, 2012 http://www.sciencedaily.com/releases/2012/11/121107141044.htm