Saturday, 10 November 2012

Human cells on a chip, the humane way for testing

There is increasing pressure for reducing animal testing in toxicity screens, necessitating the development of novel screening methods. The convergence of Lab-on-Chips (LOCs) and cell biology has permitted the study of human physiology in an organ-specific context, introducing a novel model of in vitro multicellular human organisms. One day, they will perhaps abolish the need for animals in drug development and toxin testing.
Organs-on-chips will vary in design and approach between different researchers. As such, validation and optimization of these systems will likely be a long process. Organs that have been simulated by microfluidic devices include the heart, the lung, kidney, artery, bone, cartilage, skin and more.
Building valid artificial organs requires not only a precise cellular manipulation, but a detailed understanding of the human body’s fundamental intricate response to any event. A common concern with Organs-on-Chips lies in the isolation of organs during testing. “If you don’t use as close to the total physiological system that you can, you’re likely to run into troubles” says William Haseltine, founder of Rockville, MD. Microfabrication and microfluidics offer the prospect of modeling sophisticated in vitro physiological responses under accurately simulated conditions.
In the early phase of drug development, animal models were the only way of obtaining in vivo data that would predict the human pharmacokinetic responses. However, experiments on animals are lengthy, expensive and controversial. For example, animal models are often subjected to mechanical or chemical techniques that simulate human injuries. There are also concerns with regards to the validity of such animal models, due to deficiency in cross-species extrapolation. Moreover, animal models offer very limited control of individual variables and can be cumbersome to harvest specific information.
Therefore, mimicking a human’s physiological responses in an in vitro model needs to be made more affordable, and needs to offer cellular level control in biological experiments: biomimetic microfluidic systems could replace animal testing. The development of MEMS-based biochips that reproduce complex organ-level pathological responses could revolutionize many fields, including toxicology and the developmental process of pharmaceuticals and cosmetics that rely on animal testing and clinical trials.
Using animal models to look for new drug targets or measure the effects of existing drugs can be costly and time-consuming. Even worse, as the FDA reported nine out of ten clinical trials fail as results from animal models translate poorly during human testing. The other major practice, experimenting with human cell cultures, is far from ideal as many cell lines have been turned cancerous so that they proliferate indefinitely. What you get is a convenient and abundant cell resource, but those cells have a markedly different physiology than cells in the human body.
Investment for research seems promising as, DARPA and the FDA announced a new $70 million program called Tissue Chip for Drug Testing, aiming to study the micro-environments of various human organs without ever using a scalpel.
This project asks scientists to build 10 different organs-on-chips, link them together to mimic the real body, and design software that can automatically control fluid flow and perform analysis.
The Wyss Institute at Harvard, Vanderbilt University, Cornell University, Johns Hopkins University and the University of California-Berkeley are among the partners in this new project. At Vandy, researchers will endeavor to study the brain and its difficult barriers, which prevent various drugs from crossing into the brain. The trickiest is the blood-brain barrier, which enables certain compounds the brain needs to function, but blocks most everything else, including potentially helpful drugs. A new “microbrain” would study these abilities by combining a sliver of a human brain, a chamber filled with cerebral spinal fluid, and blood vessels, which together would function just like a real brain.
The future of this technology will one day lead to possible cures for all types of diseases, considering human cells are under scrutiny for a number of situations. The hope is to use cells from individual patients for personalized treatments, which will reduce the risk of an allergic response or gene therapy. In the far future this technology may develop further with the rise of neural connections for  simulating a thought process. Although a 64 rack super computer is equal to a honey bees brain, its far from the singularity the process power of a human brain.
 The possibility of mimicking human test subjects for mechanical biological interactions is now a reality. Considering we can see in real time the cells and how they begin to change to certain situations, hopefully we can find quickly the medicines that will prove effective fighting fighting cancer to toxins and an assortment of human diseases. The lab on a chip will be the humane answer for what the animal activist are crying out for, humans testing humans with no consequences....

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