Abstract 193: Analysis of Platelet Lysate Hydrogel and Fibrinogen Gel Intramuscular Injection on Neo-Angiogenesis in Ischemic Limbs

Abstract

Introduction: We have recently characterized the in vitro benefits of the fibrin-rich pooled human platelet lysate (PL) in gel form on mesenchymal stem cells’ angiogenic activity. This study aimed to investigate the potential angiogenic activity of PL gel compared to a fibrin hydrogel (FG) in a murine model of hind limb ischemia (HLI). Methods: S129 male and female mice aged 20-weeks (n = 30) underwent right femoral artery ligation to induce HLI and were randomized to five groups: G1) Sham (n=5); G2) HLI-no treatment (n=5); G3) Saline (n=5; G4) PL (N=5); and G5) FG (n=5). The treatment limbs received PL, FG or saline by injection of 200 μL in the adductor muscle at day 0. Perfusion was quantitated with Laser Doppler Perfusion Imaging (LDPI) at 1-day post-procedurally and weekly for 28 days, and reported as ratios of the values in the ischemic limb (IL) to those in the contralateral nonischemic limb (NIL) for the adductor (thigh) and gastrocnemius (calf) areas. We then compared the change in the IL/NIL ratios for each group over the 28 days. Non-parametric analysis of variance with Dunn’s correction test was used to compare results among groups. The level of significance was set at p<0.05. Results: There were trends in the thigh and calf IL/NIL perfusion ratios at 28 days for mice injected with PL and FG compared to those with saline injections or HLI and no treatment (P>.05). Perfusion in both calf and thigh areas improved from day one to day 28 in all HLI groups. However, only PL and FG groups had significantly increased progression in thigh perfusion, and this was in comparison to sham animals. In the calf, only the FG group demonstrated a significant increase in the perfusion ratio, and this was in comparison to both HLI with no treatment and sham groups (P<.05). Conclusions: While both FG and PL gel have active angiogenic properties, FG gel alone, and not PL gel, demonstrated superior in vivo angiogenic response in this model of HLI.