Researchers at the University of Birmingham in the United Kingdom have developed a microfluidic device that mimics a human vein, including anatomical features such as valves, and physiological features such as pulsatile flow. The device is intended to make it easier to study processes such as blood clotting, which could help scientists to develop new treatments for conditions such as deep vein thrombosis. The valves can open and close during flow, mimicking the real deal, and the central channel of the device is lined with endothelial cells. The researchers hope that the technology will provide plenty of insights without the need to use animal models.
Deep vein thrombosis involves blood clot development, most often in the blood vessels of the legs. These clots can become detached and travel around the body, potentially causing serious problems if they lodge in other areas, such as the lungs or brain. Understanding the factors involved in clot development will help clinicians to develop new treatments or preventative strategies for the condition.
However, at present, much of the research on thrombosis and other cardiovascular diseases involves the use of animal models. While these models can provide a lot of information, they do not always recapitulate the human condition very well. Moreover, they entail ethical concerns and are expensive and time-consuming to perform.
Researchers have been developing benchtop alternatives to animal models, and often such innovations involve microfluidic systems. “The principles of the 3Rs – to replace, reduce and refine the use of animals in research – are embedded in national and international legislation and regulations on the use of animals in scientific procedures,” said Alexander Brill, one of the creators of the new device. “But there is always more that can be done. Innovations such as the new device created for use in thrombosis research are a step in the right direction.”
The device contains a central microfluidic channel which is lined with endothelial cells. A nutrient liquid acts as blood and it is pumped through the device in consecutive pulses, just like our own circulation. The researchers fashioned flexible valves within the channel, that open and close with the pulsatile flow and help to keep the blood moving in one direction only, just like our own vascular valves.
“The device is more advanced than previous models because the valves can open and close, mimicking the mechanism seen in a real vein. It also contains a single layer of cells, called endothelial cells, covering the inside of the vessel,” said Brill. “These two advances make this vein-on-a-chip a realistic alternative to using animal models in research that focuses on how blood clots form. It is biologically reflective of a real vein, and it also recapitulates blood flow in a life-like manner.”
Study in journal Frontiers in Cardiovascular Medicine: Platelet accumulation in an endothelium-coated elastic vein valve model of deep vein thrombosis is mediated by GPIb[alpha]-VWF interaction
Flashbacks: Blood-Vessel-On-a-Chip Helps Identify Safer Clot Prevention Drug; Blood Vessel on a Chip to Study Angiogenesis and Test Anti-Cancer Drugs; Micro-Aneurysm-On-A-Chip to Model Vascular Disease
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