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Background: Human Platelet Lysate (hPL) is a platelet-derived and growth factor-rich supplement for cell culture. It can be prepared from surplus platelet concentrates initially intended for transfusion. Amotosalen-based photochemical pathogen inactivation of platelet concentrates is used in a number of blood establishments worldwide to minimize the risk of pathogen transmission from donor to patient., Methods: This pathogen inactivation method has not been formally validated for direct use on hPL. Here, we have studied the impact of pathogen inactivation on hPL and compared it to untreated hPL prepared from pathogen-inactivated platelet concentrates or control hPL. We used mass spectrometry, ELISA, and in vitro mesenchymal stem cell culture for determining residual amotosalen, final growth factor content, and cell doubling, respectively., Results: The data have shown amotosalen concentrations to be reduced a thousand-fold following pathogen inactivation, leaving trace quantities of photosensitizer molecules in the final hPL product. Some growth factors have been reported to be significantly more impacted in hPL that is directly pathogen-inactivated compared to both control conditions. This has no significant effect on the growth kinetics of adipose-derived mesenchymal stem cells., Conclusion: Direct amotosalen-based pathogen inactivation has a measurable impact on certain growth factors in hPL, but this does not outweigh the likely benefits of reducing the odds of donor-to-patient pathogen transmission., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: We aimed to develop a single step method for the production of human platelet lysate (hPL). The method must result in high hPL yields, be closed system and avoid heparin use., Study Design and Methods: The method aimed at using glass beads and calcium. An optimal concentration of calcium and glass beads was determined by serial dilution. This was translated to a novel method and compared to known methods: freeze-thawing and high calcium. Quality outcome measures were transmittance, fibrinogen and growth factor content, and cell doubling time., Results: An optimal concentration of 5 mM Ca 2+ and 0.2 g/ml glass beads resulted in hPL with yields of 92% ± 1% (n = 50) independent of source material (apheresis or buffy coat-derived). The transmittance was highest (56% ± 9%) compared to known methods (<39%). The fibrinogen concentration (7.0 ± 1.1 μg/ml) was well below the threshold, avoiding the need for heparin. Growth factor content was similar across hPL production methods. The cell doubling time of adipose derived stem cells was 25 ± 1 h and not different across methods. Batch consistency was determined across six batches of hPL (each n = 25 constituting concentrates) and was <11% for all parameters including cell doubling time. Calcium precipitation formed after 4 days of culturing stem cells in media with hPL prepared by the high (15 mM) Ca 2+ method, but not with hPL prepared by glass bead method., Discussion: The novel method transforms platelet concentrates to hPL with little hands-on time. The method results in high yield, is closed system, without heparin and non-inferior to published methods., (© 2022 The Authors. Transfusion published by Wiley Periodicals LLC on behalf of AABB.)