The role of platelet-rich plasma in the mild and severe stages of atherosclerotic disease in mice.

Background: Platelet-rich plasma (PRP) has a high concentration of growth factors (GFs), which present a therapeutic wound healing effect. Despite having been correlated with an immunomodulatory function, the administration of PRP has not yet been investigated in atherosclerosis models. Aim: Evaluate the effect of lyophilized PRP on atherosclerosis in mice models through serum analysis. Methods: Animals received a high-fat diet for disease induction and a weekly PRP retro-orbital application. Effectiveness was evaluated by measuring inflammatory markers in plasma following the treatment of mice with either PRP or saline solution. Results: PRP was well characterized for platelet and GF concentrations; the atherosclerotic profile was established. Cytokine concentrations were altered after PRP applications. Conclusion: PRP could modulate the inflammatory pattern in the early stages of atherosclerosis.

Platelet-rich plasma (PRP) contains growth factors, which stimulate normal wound healing. This product seems to be a good modulator of white blood cells and has not been investigated in atherosclerosis. This study aimed to evaluate PRP in atherosclerosis using mice models. The PRP was produced from animals and preserved using the lyophilization technique; the product was then applied weekly in the vein. For atherosclerosis induction, genetically modified animals were fed a high-fat diet. The effectiveness was evaluated by measuring plasma inflammatory markers after treatment, and PRP seemed to alter cell-signaling molecules (cytokines). This study concluded that PRP was capable of modulating the inflammatory pattern during the early stages of atherosclerosis.

The effect of lyophilized platelet rich-plasma on skin aging: a non-randomized, controlled, pilot trial.

Platelet-rich plasma (PRP) showed positive results in the improvement of skin aging. Lyophilized PRP can be interesting in clinical practice due to the facility to obtain many samples in a single blood collection and can be used in multiple injections. To evaluate the effect of lyophilized PRP in the treatment of skin aging, through a Phase II pilot study. Nineteen women (54 years ± 7 years) with Glogau photoaging II and III types were select for this non-randomized, split-face controlled study. They received monthly intradermal injections of lyophilized PRP and saline solution (as control) into the facial skin, during a period of 2 months. The evaluation was performed by imaging method, histological techniques, and multiphoton microscopy. Although lyophilized PRP presented 10 times the platelet baseline value (P < .0001) and growth factors in adequate levels, only saline solution showed an increase of dermis thickness (p = .0009). Collagen pre and post-application remained the same for both types of treatments. The use of lyophilized PRP by mesotherapy showed no improvement on skin aging. TRIAL REGISTRATION APPROVAL: RBR-3n9wxw, UTN U1111-1226-6093-retrospectively registered.

Platelet-rich plasma lyophilization enables growth factor preservation and functionality when compared with fresh platelet-rich plasma.

AIMS: To compare levels and activity of the growth factors between fresh and lyophilized platelet-rich plasma (PRP). METHODS: Analysis of platelet concentration using fibroblast and human umbilical vein endothelial cell cultures were compared between fresh and lyophilized PRP obtained from peripheral blood. RESULTS: After lyophilization, 54% of platelets were intact whereas the fresh showed no aggregation with agonists (levels under 20%). The concentration of growth factors (VEGF, EGF, TGF-ß and PDGF) in both products were similar. Fresh and lyophilized PRPs induced proliferation in the fibroblasts at 24 h (0.303 vs 0.300, respectively). CONCLUSION: Lyophilized PRP appears to be an alternative to fresh PRP and the results evidenced the role of growth factors as a key element in the activity of this product.

In vitro study of the role of thrombin in platelet rich plasma (PRP) preparation: utility for gel formation and impact in growth factors release.

INTRODUCTION: The use of PRP has been studied for different fields, with promising results in regenerative medicine. Until now, there is no study in the literature evaluating thrombin levels in serum, used as autologous thrombin preparation. Therefore, in the present study we evaluated the role played by different thrombin concentrations in PRP and the impact in the release of growth factors. Also, different activators for PRP gel formation were evaluated. METHODS: Thrombin levels were measured in different autologous preparations: serum, L-PRP (PRP rich in leukocytes) and T-PRP (thrombin produced through PRP added calcium gluconate). L-PRP was prepared according to the literature, with platelets and leukocytes being quantified. The effect of autologous thrombin associated or not with calcium in PRP gel was determined by measuring the time of gel formation. The relationship between thrombin concentration and release of growth factors was determined by growth factors (PDGF-AA, VEGF and EGF) multiplex analysis. RESULTS: A similar concentration of thrombin was observed in serum, L-PRP and T-PRP (8.13 nM, 8.63 nM and 7.56 nM, respectively) with a high variation between individuals (CV%: 35.07, 43 and 58.42, respectively). T-PRP and serum with calcium chloride showed similar results in time to promote gel formation. The increase of thrombin concentrations (2.66, 8 and 24 nM) did not promote an increase in growth factor release. CONCLUSIONS: The technique of using serum as a thrombin source proved to be the most efficient and reproducible for promoting PRP gel formation, with some advantages when compared to other activation methods, as this technique is easier and quicker with no need of consuming part of PRP. Noteworthy, PRP activation using different thrombin concentrations did not promote a higher release of growth factors, appearing not to be necessary when PRP is used as a suspension.