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3D Printing at UC-San Diego Gets Another Step Closer to Real Printed Liver
February 9, 2016
According to 3DPrint.com, researchers at UC San Diego (UCSD) have developed a new tissue that closely mimics the structure and function of a real human liver. The liver is a very diverse organ that performs a slew of essential tasks in the body including the filtration of toxins, breaking down fats, and making important proteins. Given these functions, liver failure has dire consequences for a person.
As is noted by 3DPrint, in the field of bioprinting, there are almost as many methods for doing it as the teams themselves. In the case of UCSD, the latest technique involves taking stem cells from the skin of a patient and combining them with endothelial and mesenchymal cells. This method was developed by Dr. Shaochen Chen, Professor of Nanoengineering, whose research focus is on bioprinting. The stem cells are considered to be "pluripotent", which means they have the ability to develop into several types of tissue. Also, because the cells are taken directly from a patient’s skin means that no invasive procedures are needed to get liver cells.
Once the cells have been harvested and combined, they are printed into squares measuring just 3mm x 3mm and 200 micrometers thick. It is reportedly a significantly quicker process—it takes seconds—than many other forms of bioprinting that can take several hours to complete. Once printed, the cells are then cultured in vitro for roughly three weeks which results in them being converted to tissue. The newly developed tissue has been tested and was found to be able to emulate key liver functions including albumin secretion and urea production for a longer time than other models that have been developed to this point. Further, the fabricated liver tissue was able to produce higher levels of one enzyme that is counted on to metabolize many drugs.
According to Dr. Shu Chien, a co-author on the study, "The liver is unique in that it receives a dual blood supply with different pressures and chemical constituents. Our model has the potential of reproducing this intricate blood supply system, thus providing unprecedented understanding of the complex coupling between circulation and metabolic functions of the liver in health and disease."
To put this discovery into some perspective, according to Dr. Chen, to get a drug approved by the FDA is generally about a 12-year process as well as a hefty investment ($1.8 billion). That said, 90% of drugs cannot get past animal or human clinical trials, which leaves the pharmaceutical companies beginning back and square one. With something like this tissue that so closely resembles true function of a human liver, drug companies can begin with pilot studies almost immediately, thus enabling them to narrow down their development to drugs that have the most legitimate chance of reaching the market before going to clinical trial, saving companies much effort and money.
Among the biggest advantages of this tissue technique is that it uses stem cells taken directly from the patient, allowing for drugs to be developed for specific individuals and may eventually lead to the ability to develop patient-specific organs.