Association of Cardiac Function and Endothelial Dysfunction with Osteoprotegerin in Children and Adolescents with Type 1 Diabetes Mellitus

Abstract

Background: Diabetes complications represent a huge burden for patient and health services. Endothelial dysfunction is a systemic pathological condition which can be broadly defined as an imbalance between vasodilating and vasoconstricting substances produced by the endothelium or overall functions of the endothelium Osteoprotegerin ( a soluble glycoprotein that is produced by a wide range of tissues, including the cardiovascular system) is believed to be increased with the severity of complications in diabetic patients. Aim of the study: To estimate the level of serum osteoprotegerin in type 1 diabetic children & adolescents and study its relation to endothelial cell function and cardiovascular affection in these patients. Methodology: one year cross sectional study on 40 diabetic children and adolescents with type 1 DM from pediatric diabetic clinic, Ain shams university. All patients subjected to full history taking, laboratory investigations (lipid profile, Microalbuminuria, HbA1C & serum osteoprotegerin) and radiological investigations ( M-mode, Doppler & Tissue Doppler echocardiography, cIMT , aIMT measurement and FMD of brachial artery). Results: serum osteoprotegerin was significantly higher in diabetics compared to controls. The absolute difference and the delta change in the brachial artery diameter was significantly reduced in patients compared to controls . A high statistically significant increase was found in cIMT in patients compared to controls. Diastolic dysfunction is proved in all of our studied diabetics in form of E/A, Em/Am, Et/At, and tei index by Doppler and Tissue Doppler. A significant difference was found in E/A ratio in patients compared to control group. Ejection fraction was significantly decreased and Fs% was significantly highly decreased in patient compared to control group. A high statistically significant positive correlation was found between serum OPG and serum triglycerides. A high statistically significant negative correlation was found between HDL and diastolic function. in multiregression analysis : The factor with the strongest impact on Brachial Artery flow mediated dilation in our patients are LDL level and age. Conclusion: serum osteoprotegerin, lipid profile, flow mediated dilation of brachial artery and echocardiography provide a good predictive value for endothelial dysfunction and cardiac complication, providing that lipid profile has a big role in the current study. Abbreviation: aIMT= aortic intimal medial thickness, cIMT= carotid intimal medial thickness, Ef= ejection fraction, FMD= flow-mediated dilation, Fs= fractional shortening, HbA1c= Glycosylated hemoglobin, HDL= high-density lipoprotein cholesterol, LDL= low-density lipoprotein cholesterol, OPG= osteoprotegerin, TG= Triglycerides Key words: diabetes, type 1 DM, children, osteoprotegerin, flow mediated dilation, brachial artery, endothelial dysfunction, cIMT, aIMT, Doppler, Tissue Doppler.