Effect of Revascularization on Intramuscular Vascular Endothelial Growth Factor Levels in Peripheral Arterial Disease

Vascular endothelial growth factor (VEGF) is a potent driver of angiogenesis, which may help to relieve ischemia in peripheral arterial disease (PAD). We aimed to investigate the role of intramuscular VEGF in ischemic and non-ischemic skeletal muscle in PAD patients before and after surgical or endovascular revascularization and different stages of PAD. Biopsies of the gastrocnemius and vastus muscles from twenty PAD patients with stenosis or occlusion of the superficial femoral artery were obtained both during revascularization and 8 weeks postoperatively. The gastrocnemius muscle was considered ischemic, while vastus muscle biopsies served as intraindividual controls. The levels of vascular endothelial growth factor in muscle lysates were then determined by ELISA. Preoperative VEGF levels were significantly higher in ischemic muscles compared to the controls (98.07 ± 61.96 pg/mL vs. 55.50 ± 27.33 pg/mL, p = 0.004). Postoperative values decreased significantly (p = 0.010) to 54.83 ± 49.60 pg/mL in gastrocnemius biopsies. No significant change was observed in vastus muscle biopsies, with mean postoperative VEGF values found at 54.16 ± 40.66 pg/mL. Since all patients still had indications for revascularization, impairment of angiogenesis mechanisms can be assumed. More research about angiogenesis in PAD is needed with the ultimate goal to improve conservative treatment

The effect of locally applied Platelet-rich Plasma, Mesenchymal Stromal Cells and the combination of both on avascular meniscal healing and the level of TGF-β1 and FGF-2

Einleitung: Die inneren zwei Drittel (avaskulärer Anteil) des Meniskus weisen eine schlechtere Heilungsrate im Vergleich zum peripheren, vaskularisierten Drittel auf. In Tierversuchen konnte für thrombozytenreiches Plasma (PrP) und mesenchymale Stromazellen (MSCs) gezeigt werden, dass sie die Heilungstendenz avaskulärer Meniskusläsionen partiell verbessern, ohne jedoch konstant zur Heilung zu führen. Die kombinierte Anwendung von PRP + MSCs zeigte in vitro eine Potenzierung der Heilungseffekte. Eine wichtige Rolle wird hierbei (den im PrP besonders hoch konzentrierten) Wachstumsfaktoren zugeschrieben: Transforming Growth Factor-β1 (TGF-β1) und Fibroblasten Growth Factor-2 (FGF-2) erhöhen u.a. die Produktion extrazellulärer Matrix, wirken aber auch als Signalmolekül auf MSCs. Das Ziel dieser Studie war es, den Effekt von PrP, MSCs und der Kombination aus beidem auf die Meniskusheilung und die Konzentrationen von TGF-β1 und FGF-2 zu untersuchen. Methodik: Ein longitudinaler Riss wurde in den avaskulären Teil der Innenmenisken von 30 Schafen gesetzt und in fünf unterschiedlichen Therapieverfahren behandelt (n = 6 pro Gruppe): (1) Naht, (2) Scaffold, (3) Naht + Scaffold + PrP, (4) Naht + Scaffold + MSCs, und (5) Naht + Scaffold + PrP + MSCs. Die kontralateralen Menisken dienten als individuelle Referenz für die Untersuchung der Wachstumsfaktorveränderung. Nach acht Wochen wurden die Tiere euthanasiert und die Heilung makroskopisch beurteilt. Des Weiteren wurden die Konzentrationen von TGF-β1 und FGF-2 mittels ELISA bestimmt. Radiäre Meniskusschnitte wurden immunhistochemisch gegen TGF-β1 gefärbt und positiv gefärbte Zellen in der vaskulären, periläsionalen und avaskulären Zone gezählt. Die statistische Signifikanz wurde mit Hilfe des Wilcoxon - Tests sowie der Kruskal - Wallis - und Dunn - Tests überprüft. Das Signifikanzlevel betrug p ≤ 0,05. Ergebnisse: Makroskopisch ließ sich nach acht Wochen in keiner Gruppe eine Heilung nachweisen. Immunhistochemisch deutete sich in allen operierten Gruppen eine Zunahme von TGF-β1 positiven Zellen im Vergleich zu den kontralateralen Menisken an. Dies konnte mittels ELISA für die (2) Scaffold- und (3) PrP- Gruppe bestätigt werden. Die Konzentrationen von FGF-2 in der Naht- und PrP + MSC-Gruppe waren signifikant verringert. Zwischen den Therapiegruppen konnte kein signifikanter Unterschied festgestellt werden. Schlussfolgerungen: Weder die isolierte, lokale Applikation von PrP oder MSCs noch die Kombination aus beidem verbesserten die Heilung der avaskulären Meniskusrisse. Im Vergleich zu den nicht operierten Menisken ließen sich in den operierten Menisken, unabhängig von der Therapie, acht Wochen postoperativ erhöhte Konzentrationen von TGF-β1 und verringerte Konzentration von FGF-2 immunquantitativ nachweisen.Introduction: Tears of the inner two thirds (avascular zone) of the meniscus poorly heal compared to tears in the peripheral (vascular) third. Growth factors play an essential role for healing. Recently, animal studies furnished evidence for both platelet-rich plasma (PrP) and mesenchymal stromal cells (MSCs) to improve healing of meniscus tears in the avascular zone. Furthermore, in vitro studies showed that the combination of PrP and MSCs increased their positive effect on healing. One reason for the additive effect is that growth factors like Transforming Growth Factor-β1 (TGF-β1) and Fibroblast Growth Factor-2 (FGF-2), which are liberally available in platelets, stimulate synthesis of extracellular matrix and differentiation of MSCs. Furthermore, both growth factors have been identified to improve healing of meniscal tears. The aim of the present study was to evaluate the effect of PrP, MSCs and the combination of both on meniscal healing in vivo and to quantify levels of TGF-β1 and FGF-2. Methods: In five groups, each with six sheep, a longitudinal tear in the avascular region of medial menisci was created and treated with: (1) suture, (2) suture + scaffold, (3) suture + scaffold + PrP, (4) suture + scaffold + MSCs, and (5) suture + scaffold + PrP + MSCs. Contralateral, healthy menisci served as reference for the individual difference in growth factor levels. Euthanasia was performed after eight weeks and macroscopic healing was evaluated. Levels of TGF-β1 and FGF-2 were quantified using an ELISA. Radial menisci slices were stained immunohistochemically (IHC) for TGF-β1, subdivided into vascular, perilesional and avascular zones and stained cells were counted. Statistical analysis was performed with Kruskal - Wallis -, Wilcoxon-and Dunn-Tests. Significance level was set to p ≤ 0.05. Results: Macroscopic healing was not observed in any group after eight weeks. IHC indicated an increase of TGF-β1 in every group, which was confirmed by ELISA for group (2) scaffold and (3) PrP. FGF-2 levels were decreased in every group compared to the contralateral menisci, but statistically significant only in group (1) suture and group (5) PrP + MSCs. No significant differences were found between the established treatment groups. Conclusion: Neither PrP nor MSCs nor the combination of both improved healing of avascular meniscus tears. Increased levels of TGF-β1 were detected eight weeks after surgery whether PrP and/or MSCs were added or not. Levels of the anabolic growth factor FGF-2 were decreased after eight weeks no matter whether MSCs and/or PrP were applied

Effect of Revascularization on Intramuscular Vascular Endothelial Growth Factor Levels in Peripheral Arterial Disease

Vascular endothelial growth factor (VEGF) is a potent driver of angiogenesis, which may help to relieve ischemia in peripheral arterial disease (PAD). We aimed to investigate the role of intramuscular VEGF in ischemic and non-ischemic skeletal muscle in PAD patients before and after surgical or endovascular revascularization and different stages of PAD. Biopsies of the gastrocnemius and vastus muscles from twenty PAD patients with stenosis or occlusion of the superficial femoral artery were obtained both during revascularization and 8 weeks postoperatively. The gastrocnemius muscle was considered ischemic, while vastus muscle biopsies served as intraindividual controls. The levels of vascular endothelial growth factor in muscle lysates were then determined by ELISA. Preoperative VEGF levels were significantly higher in ischemic muscles compared to the controls (98.07 ± 61.96 pg/mL vs. 55.50 ± 27.33 pg/mL, p = 0.004). Postoperative values decreased significantly (p = 0.010) to 54.83 ± 49.60 pg/mL in gastrocnemius biopsies. No significant change was observed in vastus muscle biopsies, with mean postoperative VEGF values found at 54.16 ± 40.66 pg/mL. Since all patients still had indications for revascularization, impairment of angiogenesis mechanisms can be assumed. More research about angiogenesis in PAD is needed with the ultimate goal to improve conservative treatment.info:eu-repo/semantics/publishe