ABSTRACT
BACKGROUND: Intermedin (IMD), a novel peptide related to calcitonin gene-related peptide (CGRP) and adrenomedullin (ADM), may have localized actions as a modulator of cardiac function. The aim of the study is to explore the effect of IMD on angiotensin II (Ang II) and endothelin-1 (ET-1) induced hypertrophy in ventricular myocytes of neonatal rat and to try to elucidate the possible mechanism. METHODS: Neonatal rat cardiomyocytes were cultured in serum-free medium with and without AngII (1 micromol/L) or ET-1 (60 micromol/L) in the presence and absence of IMD (1 micromol/L). Hypertrophic responses (including cell surface area, alpha-actin, and beta-myosin heavy chain mRNA expression) and cardiomyocyte expression of NADPH oxidase gp91phox were determined. RESULTS: Ang II induced increases in cardiomyocyte size to 305 +/- 32 microm2 (n = 198, p < 0.05, at 48 hours), alpha-actin expression to 4 +/- 2.8-fold (n = 6, p < 0.05, at 48 hours) and beta-myosin heavy chain expression to 11 +/- 4.8-fold (n = 6, p < 0.05, at 48 hours), and expression of the gp91phox subunit of NADPH oxidase to 29.4 +/- 12.7-fold (n = 6, p < 0.05, at 48 hours). These effects were all significantly inhibited by IMD; cardiomyocyte size, alpha-actin expression, beta-myosin heavy chain expression, and gp91phox expression were reduced to 265 +/- 32 microm2 (n = 374, p < 0.05), 3.0 +/- 1.7-fold (n = 6, p < 0.05), 8.7 +/- 4.9-fold (n = 6, p < 0.05), 3.9 +/- 3-fold (n = 6, p < 0.05), respectively. IMD also significantly inhibited ET1-induced increases in cardiomyocyte size and superoxide generation. CONCLUSIONS: IMD exerts an antihypertrophic effect on neonatal cardiomyocytes by reduced levels of superoxide, suggesting that an antioxidant action contributes to the antihypertrophic actions of IMD.
Subject(s)
Adrenomedullin/pharmacology , Angiotensin II/toxicity , Cardiomegaly/chemically induced , Cardiomegaly/prevention & control , Endothelin-1/toxicity , Myocytes, Cardiac/drug effects , Neuropeptides/pharmacology , Actins/biosynthesis , Actins/genetics , Actins/metabolism , Analysis of Variance , Animals , Animals, Newborn , Cardiomegaly/metabolism , Cardiomegaly/pathology , Cell Size/drug effects , Cells, Cultured , Drug Interactions , Gene Expression/drug effects , Heart Ventricles/cytology , Heart Ventricles/drug effects , Membrane Glycoproteins/biosynthesis , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Myocytes, Cardiac/cytology , Myocytes, Cardiac/pathology , Myosin Heavy Chains/biosynthesis , Myosin Heavy Chains/genetics , Myosin Heavy Chains/metabolism , NADPH Oxidase 2 , NADPH Oxidases/biosynthesis , NADPH Oxidases/genetics , NADPH Oxidases/metabolism , Protective Agents/pharmacology , Rats , Rats, Sprague-Dawley , Real-Time Polymerase Chain ReactionABSTRACT
In this paper, we described the symptoms and treatment of a patient with diabetic nephropathy accompanied by spontaneous retroperitoneal hemorrhage after hemodialysis. An elderly female patient with diabetic nephropathy presented with severe pain, numbness, and an increasing swelling in the left hip and left thigh after six sessions of hemodialysis involving the use of an antiplatelet drug and an anticoagulant agent. Her hemoglobin decreased to 46 g/L. An abdominal ultrasound showed a hematoma in the left retroperitoneal space, and computed tomography (CT) findings revealed a 6 cm × 8 cm × 10 cm hematoma in the left psoas muscle. After aggressive supportive therapy [the administration of packed red blood cell transfusion, carbazochrome sodium sulfonate injection, and continuous venovenous hemofiltration (CVVH)], the patient's vital signs stabilized and her hemoglobin increased to 86 g/L. Repeat CT showed that the hematoma had been partially absorbed after two weeks. Eventually, the patient was discharged with stable vital signs. Physicians should be aware of the possibility of spontaneous retroperitoneal hemorrhage, particularly in patients with diabetic nephropathy undergoing hemodialysis involving the use of anticoagulant agents.
