Bioengineering Platelets: In Vitro Formation
In a recent issue of the Blood Journal, scientists from the Brigham and Women’s Hospital (BWH) in Boston announced that they have developed a method of artificially manufacturing functional human platelets in vitro. This announcement could solve the problem of blood transfusion supply shortages, which affect millions around the world each year.
The platelet bioreactor, developed by Platelet BioGenesis, functions by mimicking microenvironments of both bone marrow and blood vessels to trigger platelet production on a dual-chambered biochip. Past attempts at artificially generated platelets were created in Petri dishes, a much slower process. The new device increases platelet production by 90 percent. It takes just two hours to produce platelets with the bioreactor, compared to 18 hours with a Petri dish.
The Risk of Platelets
Platelet transfusions are an essential component of treatment for patients facing life threatening health problems including: cancer, anemia, AIDS, organ transplant surgeries, bone marrow transplant, major trauma and sepsis. Platelets (also known as thrombocytes) are instrumental in blood clotting, thereby preventing excessive bleeding. More than 7,000,000 units of platelets are transfused each year in the United States.
Platelet transfusions are integral to the treatment of many illnesses. When not properly checked for contamination, recipients of platelet transfusions can face severe medical consequences and even death.
Although necessary for the survival of many patients, platelet transfusions pose a risk for recipients. Bacterial contamination of platelets is the leading cause of transfusion-transmitted infectious risk and the second most common cause of transfusion-related deaths in the United States. Roughly 1 in 1,000 platelet units are contaminated with bacteria. There are tests to confirm safety of platelets, however, many hospitals avoid more in-depth testing due to the costs and perceived minimal risk. When the Food and Drug Administration approved a new contamination test 2007 that was proven highly effective, hundreds adopted the approach while many more hospitals chose to opt out. The University of Maryland Medical Center was one of those reluctant to implement the option due to an estimated $500,000 yearly increase in costs on top of the $16 million the center spends each year on platelets.
The cost of these tests would have been well worth it to Jessica Rose Kohut’s parents, who lost their six-year-old daughter while she was undergoing treatment for a rare form of cancer known as Stage IV neuroblastoma at All Children’s Hospital in St. Petersburg, FL. The tragedy of her story is that she could have lived many years more had she not received a platelet transfusion that was contaminated with viridans streptococci. As a result, Jessica suffered septic shock that resulted in her death. The day before she received her transfusion, a 17-year-old boy received platelets from the same donor and suffered severe shaking and chills but doctors failed to investigate the transfusion as a possible cause.
Saving Lives with Innovation
“The ability to generate an alternative source of functional human platelets with virtually no disease transmission represents a paradigm shift in how we collect platelets that may allow us meet the growing need for blood transfusions,” said Jonathan Thon, PhD, Division of Hematology, BWH Department of Medicine, lead study author.
The American Red Cross often faces shortages of platelet supplies. The availability of artificial alternatives significantly increases availability and the chance of a successful transfusion.
In addition to increasing safety, the limited five day shelf-life has made blood platelet shortages common. Earlier this month the American Red Cross issued an urgent notice requesting donations to avoid a looming critical shortage. The ability to easily generate platelets has potential to completely eliminate critical shortages and ensure that no patient will die while waiting for a transfusion.
“By being able to develop a device that successfully models bone marrow represents a crucial bridge connecting our understanding of the physiological triggers of platelet formation to support drug development and scale platelet production,” said senior study author Joseph Italiano, Jr., PhD, Division of Hematology, BWH Department of Medicine, and the Vascular Biology Program at Boston Children’s Hospital.
Researchers expect to commence phase 0/I in human clinical trials in 2017. “The regulatory bar is appropriately set high for blood products, and it is important to us that we show platelet quality, function and safety over these next three years since we’ll likely be recipients of these platelets ourselves at some point,” said Thon.
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