PRP can enhance hPDLC adhesion, proliferation and induce the differentiation of hPDLC into mineralized tissue formation cell; thereby contribute to the main processes of periodontal tissue regeneration. For economical and biological reasons, PRP has more clinical beneficial than analogous growth factors.

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In recent years, autologous platelet-rich plasma (PRP) derivatives have been used widely in the regeneration and repair of tissue, but a standard definition and preparation method for PRP are lacking. We developed a standardized method using platelet indices as quality-control indicators for PRP preparation. Twenty-one elderly patients (9 males, 12 females) with complex wounds were treated with standardized platelet-rich plasma (S-PRP). The platelet count in PRP after the second centrifugation was 1,069-1,436 × 10 9 /L. We adjusted the platelet concentration in PRP after a second centrifugation to 1,000 × 10 9 /L according to a formula using platelet-poor plasma (PPP). The standardized preparation method that we developed gave S-PRP with a relatively uniform platelet concentration. The wounds of 21 patients showed accelerated healing after S-PRP treatment, and there were no obvious side effects during treatment. These data suggest that our preparation method of S-PRP, using platelet indices as quality-control indicators with platelet count of 1,000 × 10 9 /L could be used for the treatment of complex wounds in the elderly. The preparation method of S-PRP proposed in the present study may be a simple and effective method of PRP quality control.

In the present study, the age‐ and sex‐related differences in platelet ultrastructure were investigated using transmission electron microscopy (TEM). A total of 15 healthy volunteers were grouped according to age, with 5 people in each of the following groups: young group (25‐45 years), middle‐aged group (46‐65 years), and old‐aged group (> 65 years). In the TEM micrographs, the internal components, specifically the α‐granules, dense granules, and lysosomal granules, of 20 platelets were counted for each group. Two‐way analysis of variance of age and sex variance was used to compare the results. The ultrastructure of the platelets in the old‐aged group was observed to be quite different from those of the young and middle‐aged groups. Specifically, with ageing, the platelet membrane becomes more irregular in shape and non‐smooth, and multiple platelet membrane ruptures are observed. Furthermore, the pseudopodia and protuberances become more numerous and slender, and the number of α‐granules is significantly reduced. These morphological changes indicate that ageing may affect the function of platelets, which in turn affects the efficacy of platelet concentrates. Thus, the effects of age should be considered when using platelet concentrates prepared from elderly autologous blood.

Platelet-rich plasma (PRP) has seen wide clinical use owing to its regenerative and repair abilities. Objective: To investigate the anti-photoaging effects of pre-and post-treatment of PRP on UVB-damaged HaCaT cells. Methods: HaCaT cells were irradiated with 80 mJ/cm 2 UVB, before or after PRP treatment (1000 × 10 7 /L), and following measurements were taken: survival rate of UVB-irradiated HaCaT cells, malondialdehyde (MDA) content and activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT). Western blot was used to determine the effect of different PRP intervention on the expression of PI3K, AKT, ERK, MMP-1, MMP-9, TIMP-1 and γ-H2AX in the UVB-irradiated HaCaT cells. Results: pre-and post-PRP treatment reduced MDA content and increased the activities of GSH-Px, SOD and CAT in photoaged HaCaT cells. These changes resulted in reduced cytotoxic effects. Besides, different PRP intervention promoted cell proliferation via PI3K/AKT pathway. Furthermore, PRP application suppressed the expression of γ-H2AX. Also, PRP intervention alleviated photoaging effects by upregulating the expression level of tissue inhibitor of metalloproteinases-1 (TIMP-1) while downregulating matrix metalloproteinase (MMP) expression level in photoaged HaCaT cells. Conclusion: pre-and post-PRP treatment play anti-photoaging role through strengthening cellular oxidative defense capacity, mitigating MMP expression, alleviating DNA damages and promoting proliferation of UVB-irradiated HaCaT cells.Abbreviations: APB-PRP, adult peripheral blood-derived PRP; HaCaT, human keratinocyte cells; PRP, platelet-rich plasma; UCB-PRP, umbilical cord blood-derived PRP.