- Human platelet lysate (HPL) is a human-derived, serum-free supplement used primarily in cell culture as a replacement for fetal bovine serum (FBS). It is obtained by disrupting platelets from donor human blood, typically through freeze-thaw cycles or sonication, which releases a wide array of growth factors, cytokines, and bioactive molecules essential for cell proliferation and maintenance.
- HPL has gained increasing attention in regenerative medicine, stem cell research, and clinical cell therapy due to its human origin, high mitogenic potential, and reduced risk of xenogeneic immune reactions compared to animal-derived supplements.
- The key components of HPL include platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-β), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and insulin-like growth factor (IGF), among others. These molecules collectively promote cellular functions such as proliferation, migration, differentiation, and angiogenesis. The composition of HPL makes it particularly well-suited for expanding various cell types, including mesenchymal stem cells (MSCs), fibroblasts, endothelial cells, and other primary human cells. Compared to FBS, HPL often supports faster growth rates and better maintenance of the native phenotype and functionality of cultured cells.
- HPL production involves pooling platelet concentrates from screened human donors, followed by lysis and removal of cellular debris and coagulation factors, often through filtration and heparin supplementation. The pooling process helps minimize donor-to-donor variability, enhancing reproducibility and batch consistency. HPL can be stored frozen for extended periods without significant loss of activity. Importantly, the preparation process is typically carried out under Good Manufacturing Practice (GMP) conditions when HPL is intended for clinical use, to ensure sterility, safety, and quality control.
- The use of HPL in place of FBS aligns with ethical and regulatory efforts to minimize animal product usage in research and therapeutics. In clinical applications, such as cell-based therapies or tissue engineering, HPL significantly reduces the risk of introducing animal antigens or pathogens, which is a key concern with FBS. As a human-derived product, HPL is more immunologically compatible with human cells, reducing potential immunogenic responses upon transplantation.
- However, challenges with HPL use still exist. Variability in platelet source, preparation methods, and lack of standardized protocols can affect its performance across labs and applications. Additionally, residual plasma proteins and coagulation factors may interfere with some assays or require the addition of anticoagulants like heparin to prevent clotting in culture systems. Researchers must also ensure that HPL batches are rigorously tested for sterility, endotoxins, and mycoplasma contamination.
- In conclusion, human platelet lysate is a potent, human-compatible supplement that offers a promising alternative to animal sera in cell culture and regenerative medicine. Its rich growth factor profile, ethical sourcing, and clinical safety make it an increasingly preferred choice for expanding human cells in both research and therapeutic contexts. Ongoing efforts to standardize HPL production and quality control will further enhance its utility and acceptance in advanced biomedical applications.
