Therapeutic Angiogenesis in the Experimental Ulcerative-Necrotic Stage of Critical Lower Limb Ischemia

Abstract

Introduction. The effectiveness of therapeutic angiogenesis in the ulcerative-necrotic stage is insufficient to preserve the limb.The aim of research was to study the effectiveness of therapeutic angiogenesis with "Udenafil", mononuclear fraction of autologous bone marrow and their combination in the experimental ulcerative-necrotic stage of critical lower limb ischemia.Materials and methods. Lower leg muscle ischemia was simulated on Wistar rats. All animals were divided into 4 groups, 20 animals in each group: with simulated critical ischemia without treatment (control group); with critical ischemia and monotherapy with udenafil (udenafil, orally, 8.6 mg/kg for 28 days, the first experimental group); with critical ischemia and monotherapy with mononuclear fraction of autologous bone marrow (a single paravasal injection of a mononuclear fraction of autologous bone marrow in 7 days after critical ischemia simulation, the second experimental group); with critical ischemia and combined therapy (udenafil orally, 0.86 mg/kg, once a day, for 28 days, and a single paravasal injection with a mononuclear fraction of autologous bone marrow, similar to the group with monotherapy, the third experimental group). The level of blood microcirculation in the lower leg muscles was measured in 21 and 28 days; after that, histological examination was performed.Results. In the control group, the regional blood flow rate in the ischemic shin muscle was 2.1 times less than in intact animals in 21 days and 1.8 times less in 28 days after simulated critical ischemia. In the first experimental group, the regional blood flow rate increased by 1.6 times in 21 days and 28 days after udenafil administration; in the second experimental group, the regional blood flow rate increased by 1.6 times and 1.7 times, respectively, after the mononuclear fraction of bone marrow was administered to animals; and in the third experimental group, the regional blood flow rate increased 1.8 times, compared with the animals of the control group after the combined use of bone marrow cells and udenafil. In 28 days after the start of the experiment, histological tests detected foci of necrosis with perifocal inflammation in the ischemic muscles of the lower leg in animals of the control group. In the first and second experimental groups, a decreased size and number of necrosis sites was registered due to formation of young connective tissue and new capillaries. None of newly formed microcirculatory bed was detected. In the third experimental group, the severity of necrotic changes was minimal, a large number of newly formed blood vessels (arterioles) were visualized in wide layers of the connective tissue (capillaries, venules); this was a new microcirculatory bed.Conclusion. Application of udenafil combined with the mononuclear fraction of the bone marrow results in an increased perfusion of ischemic tissues and development of a new microcirculatory bed.