Keeping Platelets Safe: The Potential Role of Antimicrobial Peptides
Scientists at the Food and Drug Administration's Center for Biologics Evaluation and Research (CBER) found that certain synthetic antimicrobial peptides (AMPs) can inactivate bacteria in platelet concentrates and other blood components used in transfusion medicine. These bacteria are known to greatly increase the risk of sepsis and related complications, especially in immunocompromised patients.
Bacterial inactivation techniques are currently in use in a few countries, but these techniques are complex, and depending on the technology, may damage blood components. To date, FDA has not licensed any such techniques for platelets or component plasma.
Natural AMPs are a diverse group of molecules produced by a variety of cells in the body, including immune system cells called neutrophils and natural killer cells, as well as platelets. These peptides can be chemically synthesized, without losing their microbicidal effects, such as the potential to cause membrane disruption.
The CBER finding is important because transfusion of room-temperature-stored platelets contaminated with infectious bacteria, such as Staphylococcus aureus, can cause sepsis and other complications. While relatively rare, this threat is especially troublesome if the bacteria are resistant to antibiotics.
The study identified a synthetic peptide called RW3 as a particularly promising candidate for further study. This AMP demonstrated bactericidal activity in both plasma alone and platelet concentrates, significantly reducing levels of six medically important bacteria that commonly contaminate blood components and blood products.
The results of the study are a promising proof-of-concept for using AMPs as a simple, safe, and cost-effective alternative to current pathogen inactivation techniques. Ongoing experiments include evaluation of AMP-treated human platelets for in vitro quality and in vivo function in a suitable animal model to evaluate whether this approach compromises platelet function.
"Evaluation of antimicrobial peptides as novel bactericidal agents for room temperature-stored platelets"
Ketha V.K. Mohan, Shilpakala Sainath Rao, and Chintamani D. Atreya (Food and Drug Administration, Bethesda, MD)