Systematic review and meta-analysis on the use of human platelet lysate for mesenchymal stem cell cultures: comparison with fetal bovine serum and considerations on the production protocol.

Mesenchymal stem cell (MSC) culturing for cell therapies needs a step forward to be routinely used in clinical settings. Main concerns regard the use of animal origin reagents, in particular supplementing the culture medium with FBS. Lately, Human Platelet Lysate (HPL) has been proposed as animal-free alternative, described as an excellent supplement for culturing MSCs. The aim of this systematic review was to analyze the current literature on the effect of HPL and FBS on ASCs and BMSCs. The primary outcome was the proliferation rate of cells cultured with FBS and HPL. Differences in terms of doubling time (DT) and population doubling (PD) were evaluated by meta-analysis, subgrouping data according to the cell type. A total of 35 articles were included. BMSCs and ASCs were used in 65.7% (23) and 28.6% (10) studies, respectively. Only two studies included both cell types. Overall, 22 studies were eligible for the meta-analysis. Among them, 9 articles described ASCs and 13 BMSCs. The results showed that BMSCs and ASCs cultured with 10% HPL and 5% HPL have lower DT and higher PD compared to cells cultured with 10% FBS. A possible correlation between the DT decrease and the application of at least 3 freeze/thaw cycles to induce platelet lysis was found. Additionally, HPL increased VEGF secretion and maintained the immuno-modulatory abilities for both cell types. The clarification reported here of the higher efficiency of HPL compared to FBS can help the transition of the scientific community towards clinical-related procedures. 1. The meta-analysis shows that HPL induces a population doubling increase and a doubling time decrease of both ASCs and BMSCs compared to FBS. 2. When at least 3 freeze/thaw cycles are applied to induce platelet lysis, the doubling time of HPL-cultured cells is lower than FBS-cultured cells (Created with BioRender.com).