Biochip mimics how the body produces platelets so they could be made in a lab
April 21, 2013
When you hear about blood shortages, that doesn’t just mean there’s a shortage of donated red blood cells.
It could also mean platelets, a blood component that Sven Karlsson described as Band-Aids of the bloodstream, because they’re necessary for blood clot formation to help stop bleeding.
Karlsson is a co-founder and chief financial officer of Platelet BioGenesis, a Boston startup that’s developing a way to produce human platelets in a lab using a microfluidic-based bioreactor.
At least 1.5 million platelet transfusions are done in the U.S. each year, often to preventhemorrhaging in people undergoing chemotherapy for hematologic cancers. They’re also sometimes used in trauma and general surgeries.
The problem is that right now, platelets only come from donors, and each unit of donated whole blood contains only a small volume of them. Each platelet transfusion requires multiple units of whole blood. Then, once the platelets are extracted, they must be kept at room temperature to avoid activation, with a shelf life of only five days. And two of those days are spent decontaminating them of viruses and bacteria, Karlsson said.
“We looked at how platelets are created in the body,” he explained. “My co-founders’ innovation was to mimic that on a biochip.”
Platelets come from bone marrow cells called megakaryocytes, which collect along the endothelial cells that line blood vessels and extend ‘tendrils’ into blood vessels, Karlsson said. Eventually, those tendrils break off and become platelets.
Platelet BioGenesis’ biochip has two chambers with a perforated barrier in between. One chamber mimics the bone marrow micro-environment, and the other mimics the blood vessel micro-environment. The company sources stem cells from partners who generate megakaryocytes, which are then inserted into the bone marrow chamber. The cells extend proplatelets into the blood vessel chamber that eventually break off, as they do in humans.
Past attempts by others to produce human platelets from stem cells have been stifled by challenges generating sufficient numbers of megakaryocytes from starting cells and generating enough viable and functional platelets per megakaryocyte.
Karlsson said the company’s technique addresses those roadblocks as well as the concern that platelet transfusions could spread infections. “Instead of taking 18 hours, it takes us about two hours, and we get 90 percent of them converting, compared to 10 percent for existing methods,” Karlsson said. “We think we can produce a scalable alternative that will eventually be cheaper, safer and longer-lived, because they’re created in a lab without the need for a donor.
Initially, he sees the company selling bags of platelets into the existing blood supply system. But eventually, he thinks it’s possible the technology could allow on-site production of platelets using a patient’s own bone marrow cells.
Harvard researchers and Platelet BioGenesis co-founders Jonathan Thon, Linas Mazutis and Joseph Italiano spent three years developing the biochip in the lab. The company could be ready to start testing the functionality of the platelets it produces in animal models this summer.
So far the co-founders have been self-funded, but Karlsson said they may look to an equity raise over the next year.