RESUMO
Aim: The microvascular complications in type 2 diabetes mellitus are associated with high morbidity mortality. Their pathogenesis is not fully understood in spite of recent advances. Although some authors have reported normal pulmonary function in diabetics, others found abnormalities including impaired diffusing capacity. The aim of this study was to assess the presence of pulmonary microangiopathy [as determined by lung diffusing capacity for carbon monoxide, DLco] in type 2 diabetic patients and to analyze the correlation between DLco and various diabetic factors. We also aimed to association between DLco and serum levels of ACE and ET-1 [markers of endothelial damage in various diabetic microangiopathies]. Subjects and Thirty-eight type 2 diabetic patients without over lung disease and 20 age and sex-matched :ontrols were enrolled in the study. All patients ontrols were non-smokers. Glycosylated haemoglobin [HbA-1c] was measured as an indicator of control. The presence of diabetic retinopathy was detected by ophthalmoscopic examination and the presence of diabetic nephropathy was determined by measuring the 24-hour urinary albumin excretion [UAE]. A global spirometry was performed and DLco was measured by the single-breath method corrected by alveolar volume [DLcoA/VA]. Forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1] and FEV1/FVC were within normal in diabetics. Diabetic patients showed a significant reduction of% DLcoA/VA that was greater in those not receiving insulin and those with diabetic microangiopathy. The serum levels of ACE and ET-1 were significantly higher in diabetics [ACE and ET-1 level were more elevated in those with diabetic microangiopathy]. Percent DLcoA/VA was negatively correlated with serum ACE, ET-1 and UAE values. Conclusions: These data suggest the existence of microangiopathic involvement of pulmonary vessels in type 2 diabetic patients particularly in presence of retinopathy and/or nephropathy. Elevated serum levels of ACE and ET-1 as well as microalbuminuria are significant independent predictors of the existence of pulmonary microangiopathy. Insulin resistance may be central to the pathogenesis of pulmonary microangiopathy. Exogenous insulin administration, e.g. via the inhaled route, may be used in diabetics to improve their DLco