Treatment with Sildenafil and Donepezil Improves Angiogenesis in Experimentally Induced Critical Limb Ischemia

Abstract

Objectives. In this study, we aimed to demonstrate the role of sildenafil (an antagonist of phosphodiesterase type 5 (PDE-5)) and donepezil (a specific and reversible inhibitor of acetylcholinesterase (Ach)) in increasing ischemia-induced angiogenesis. Method. Critical limb ischemia was induced by ligation of the common femoral artery followed by ligation of the common iliac artery. The operated animals were divided into 3 groups: receiving sildenafil, receiving donepezil, and surgery alone; the contralateral lower limb was used as a negative control. The results were controlled based on clinical score and Doppler ultrasound. Gastrocnemius muscle samples were taken from all animals, both from the ischemic and nonischemic limb and were used for histopathological and immunohistochemical examination for the evaluation of the number of nuclei/field, endothelial cells (CD31), dividing cells (Ki-67), and vascular endothelial growth factor (VEGFR-3). Results. An increasing tendency of the number of nuclei/field with time was observed both in the case of sildenafil and donepezil treatment. The formation of new capillaries (the angiogenesis process) was more strongly influenced by donepezil treatment compared to sildenafil or no treatment. This treatment significantly influenced the capillary/fiber ratio, which was increased compared to untreated ligated animals. Sildenafil treatment led to a gradual increase in the number of dividing cells, which was significantly compared to the negative control group and compared to the ligation control group. The same effect (increase in the number of Ki-67 positive cells) was more obvious in the case of donepezil treatment. Conclusion. Donepezil treatment has a better effect in ligation-induced ischemia compared to sildenafil, promoting angiogenesis in the first place, and also arteriogenesis.

Effect of the Phosphodiesterase 5 Inhibitor Sildenafil on Ischemia-Reperfusion-Induced Muscle Mitochondrial Dysfunction and Oxidative Stress

“…Accordingly, chronic administration of sildenafil improved ischemia-induced neovascularization in hypercholesterolemic apolipoprotein E-deficient mice, reduced TNF alpha staining in the femoral artery, and reduced inflammation and oxidative stress in skeletal muscle [31,32,33].…”

“…One explanation might be that chronic treatment might be mandatory. Indeed, beneficial effects of sildenafil were observed after daily, weekly, or even longer administration [31,32,33]. However, acute sildenafil administration also demonstrated some degrees of protection [44,45,46].…”

“…It also induced protective effects during ischemia-reperfusion on several organs [24,25,26,27,28,29], supporting its potential usefulness in IR settings. PDE5 has been also shown to be expressed in skeletal muscle [21,30], and, accordingly, sildenafil reduced muscle oxidative stress and/or increased muscle angiogenesis and reduced inflammation 7 or 30 days after either femoral artery removal or unilateral hindlimb IR [31,32,33].…”

Thymosin‑β�4 induces angiogenesis in critical limb ischemia mice via regulating Notch/NF‑κB pathway

“…no. LAT-18-5901; Lab Animal Technology Develop) ( 5 ). Finally, buprenorphine hydrochloride (0.1 mg/kg; cat.…”

“…In clinical, although some therapeutic strategies exist, including surgical or interventional revascularization, substantial number of patients are not eligible for those treatments and amputation can be the only option ( 4 ). Previous studies have reported that therapeutic neovascularization is a promising option that could overcome ischemia by providing an improved vascular network ( 4 , 5 ). However, the process of neovascularization is complex and involves the induction of capillary sprouting (angiogenesis), the maturation of newly formed vessels and the growth of large-conductance vessels (arteriogenesis) to improve blood supply ( 6 - 8 ).…”