adrenomedullin and Necrosis

Flap necrosis in the distal area due to the deficiency of blood circulation is a major complication in flap treatment. In many previous studies, some natural substances such as chlorogenic acid, adrenomedullin (ADM), and glucagon-like peptide-1 (GLP-1) have been used to improve flap viability via their vasodilator, angiogenic, and antioxidant effects. The aim of this study is to clarify the mechanism through the use of selective antagonists for calcitonin gene-related peptide (CGRP) receptors and GLP-1 receptors such as CGRP-(8-37), exendin-(9-39), respectively, in the flap healing effects of ADM and GLP-1. The role of nitric oxide (NO) was investigated in the mechanism as well.. Seventy adult female Wistar rats (200 g-250 g) were used in the study. The cutaneous skin flap (8 cm x 3 cm) on the abdominal wall was raised based on the superficial inferior epigastric artery (SIEA). Single-dose substance injections were administered into the SIEA. Necrosis in the flap area was evaluated on postoperative day 7. The proportion of the necrosis area (necrosis area % = [necrosis area/flap area] x 100) and vascularity (vascular number/cm2) in the distal area were calculated.. The administrations of ADM or GLP-1 increased the vascularity and decreased the necrosis area in the distal flap region. The ADM receptor antagonist, CGRP-(8-37), did not prevent the positive effects of ADM on flap healing and vascularity. A GLP-1 receptor antagonist, exendin-(9-39), prevented the effect of GLP-1 on flap healing and vascularity. Nitric oxide mediated the beneficial effects of both peptides on flap healing.. The CGRP receptors have no direct role, but NO acts as a mediator in the beneficial effect of ADM on flap healing. The GLP-1 specific receptors and NO act as important interagents for the effects of GLP-1 on flap healing.

Topics: Adrenomedullin; Animals; Antioxidants; Calcitonin Gene-Related Peptide; Disease Models, Animal; Epigastric Arteries; Female; Glucagon-Like Peptide Receptors; Glucagon-Like Peptides; Graft Survival; Immunohistochemistry; Necrosis; Nitric Oxide; Rats; Rats, Wistar; Receptors, Calcitonin Gene-Related Peptide; Surgical Flaps; Wound Healing; Wounds and Injuries

Adrenomedullin (ADM) functions as a survival factor against hypoxic cell death. However, molecular mechanisms underlying the cell survival pathway remain largely unknown. In this report, we showed that ADM suppressed reactive oxygen species (ROS) increase by inhibiting reduction of glutathione (GSH) level in hypoxia/reoxygenation (H/R) injury, and increased the activities of glutathione peroxidase and reductase. In addition, ADM maintained total and active reduced thioredoxin (Trx) levels against H/R. We also found that ADM blocked nuclear translocation of Trx induced by H/R. The results of the present study show that ADM regulates cellular ROS levels via the GSH and Trx system.

Topics: Adrenomedullin; Cell Line, Tumor; Glutathione; Humans; Hydrogen Peroxide; Hypoxia; Necrosis; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species; Sulfhydryl Compounds; Thioredoxin-Disulfide Reductase; Thioredoxins

Extravasation of vesicant drugs such as vinca alkaloids causes severe injury, which may range from erythema to skin necrosis or ulceration. The skin necrosis may not be fully evident until several weeks or months after the initial damage, and may require surgical intervention. The main treatments for vincristine extravasation are hyaluronidase injection and topical warming, and the aim of treatment is to increase the clearance of the drug from the extravasation site.. To investigate the effect of adrenomedullin, a potent vasodilatory peptide, in rats subjected to vincristine-induced extravasation.. In total, 36 Wistar albino rats were given intradermal injection of vincristine and saline. The rats were assigned to one of three treatment groups (adrenomedullin, adrenomedullin + hyaluronidase, or hyaluronidase), a control group given vincristine only, or a sham group (saline). Tissue superoxide dismutase (SOD), glutathione peroxidase, malondialdehyde (MDA) and protein content were evaluated in skin biopsies taken on day 22. The ulcer size and histopathological grading scores were also recorded.. SOD levels were significantly increased by adrenomedullin and increased by hyaluronidase. Glutathione peroxidase levels were significantly decreased in all four vincristine groups. Tissue MDA levels were highest in the adrenomedullin group. In all four vincristine groups, MDA levels were reduced, indicating preservation from tissue injury. Protein carbonyl (PCO) content levels in the adrenomedullin group were significantly greater than in the other three study groups (P < 0.05). In contrast, PCO levels in the hyaluronidase group were significantly lower than in the other three groups.. In this animal model of vincristine-induced extravasation, antioxidant status and histology were preserved by hyaluronidase but worsened by adrenomedullin.

Topics: Adrenomedullin; Albinism; Animals; Antineoplastic Agents, Phytogenic; Disease Models, Animal; Glutathione Peroxidase; Hyaluronoglucosaminidase; Male; Malondialdehyde; Necrosis; Rats; Rats, Wistar; Skin; Skin Ulcer; Superoxide Dismutase; Treatment Outcome; Vasodilator Agents; Vincristine

Intermedin (IMD) is a novel member of the calcitonin/calcitonin gene-related peptide family. We investigated the cardioprotective mechanism of IMD(1-53) in the in vivo rat model of myocardial ischemia/reperfusion (I/R) injury and in vitro primary neonatal cardiomyocyte model of hypoxia/reoxygenation (H/R). Myocardial infarct size was measured by 2,3,5-triphenyl tetrazolium chloride staining. Cardiomyocyte viability was determined by trypan blue staining, cell injury by lactate dehydrogenase (LDH) leakage, and cardiomyocyte apoptosis by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assay, Hoechst staining, gel electrophoresis and caspase 3 activity. The translocation of mitochondrial cytochrome c of myocardia and expression of apoptosis-related factors Bcl-2 and Bax, phosphorylated Akt and phosphorylated GSK-3beta were determined by western blot analysis. IMD(1-53) (20 nmol/kg) limited the myocardial infarct size in rats with I/R; the infarct size was decreased by 54%, the apoptotic index by 30%, and caspase 3 activity by 32%; and the translocation of cytochrome c from mitochondria to cytosol was attenuated. IMD(1-53) increased the mRNA and protein expression of Bcl-2 and ratio of Bcl-2 to Bax by 81 and 261%, respectively. IMD(1-53) (1 x 10(-7) mol/L) inhibited the H/R effect in cardiomyocytes by reducing cell death by 43% and LDH leakage by 16%; diminishing cellular apoptosis; decreasing caspase 3 activity by 50%; and increasing the phosphorylated Akt and GSK-3beta by 41 and 90%, respectively. The cytoprotection of IMD(1-53) was abolished with LY294002, a PI3K inhibitor. In conclusion, IMD(1-53) exerts cardioprotective effect against myocardial I/R injury through the activation of the Akt/GSK-3beta signaling pathway to inhibit mitochondria-mediated myocardial apoptosis.

Topics: Adrenomedullin; Animals; Apoptosis; Cardiotonic Agents; Chromones; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Hypoxia; Male; Mitochondria; Morpholines; Myocardial Reperfusion Injury; Myocardium; Myocytes, Cardiac; Necrosis; Neuropeptides; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction

Adrenomedullin is a potent, endogenous vasodilator peptide synthesized and secreted by diverse locations such as adrenal glands, lungs, kidneys, vascular smooth muscle, and endothelium. Homozygous deletion of the adrenomedullin gene is embryonic lethal. We hypothesized that adrenomedullin has an important role in placental and fetal growth and development in rat pregnancy. The current study evaluated maternal systolic blood pressure, litter size, placental and pup weight, pup mortality, and placental pathology in pregnant rats following continuous in utero exposure to an adrenomedullin antagonist. Osmotic minipumps were inserted on Gestational Day 14 to continuously deliver either adrenomedullin, adrenomedullin antagonist, or vehicle control. Systolic blood pressure was recorded daily. Pregnant rats were killed on Gestational Day 15-18, 20, and/or 22 to evaluate placental development and fetal growth. The placentas were graded for the presence of necrosis in the decidua and fetal labyrinth as well as fetal vessel development in the labyrinth. A trend toward increased systolic blood pressure was noted between Gestational Days 17 and 20 in mothers treated with adrenomedullin antagonist, but the difference was not statistically significant. Antagonism of adrenomedullin function during rat pregnancy caused fetal growth restriction, decreased placental size, gross necrosis of placental margins and amniotic membranes, histologically deficient fetal vessel development in the labyrinth, and fetal edema. Adrenomedullin contributes to angiogenesis, functions as a growth factor, and helps regulate vascular tone during rat gestation.

Topics: Adrenomedullin; Amnion; Animals; Blood Pressure; Embryonic and Fetal Development; Female; Fetal Growth Retardation; Fetal Weight; Fetus; Gestational Age; Hydrops Fetalis; Litter Size; Necrosis; Peptides; Placenta; Pregnancy; Rats; Systole