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Objectives: To assess the nature of pulmonary dysfunction in type 1 diabetes and the relationship of pulmonary function tests to diabetic factors and complication. Subjects and Methods: Sixteen type 1 diabetic patients and 26 control subjects matched for age and sex were studied. We performed spirometry measurements and measured pulmonary diffusing capacity (DL_CO) in sitting and supine position by the single-breath method corrected by alveolar volume (VA). Glycosylated hemoglobin (HbA_Ic), retinopathy and microalbuminuria were included as parameters of metabolic control and diabetic complications. Results: Diabetic patients showed a significant reduction of the following pulmonary function tests (% predicted value) as compared with control subjects: total lung capacity (TLC, 92.6 ± 14.5 vs. 113.9 ± 17.5, p < 0.001), lung diffusing capacity in sitting position (DL_CO, 90.4 ± 21.1 vs. 107.7 ± 15.6, p = 0.004), lung diffusing capacity in supine position (DL_CO, 88.3 ± 19.3 vs. 111.9 ± 19.9, p = 0.001). The differences in diffusing capacity corrected by alveolar volume in sitting and supine position (DL_CO/VA) were not significant. By changing the posture from sitting to supine position both diabetic patients and control subjects significantly increased DL_CO/VA (103.4 ± 17.7 vs. 112.7 ± 22.3, p = 0.046 and 99.5 ± 13.4 vs. 114.4 ± 13, p < 0.001, respectively). There was no correlation between pulmonary function tests and diabetic complications. Conclusion: These data indicate that type 1 diabetic patients showed reduced TLC and DL_CO, features of pulmonary restrictive dysfunction. There was no correlation between abnormal pulmonary function and the presence of other diabetic complications.

Raised serum levels of adhesion molecules are believed to reflect endothelial activation and may contribute to the development of diabetic vascular complications. The aim of this study was to clarify the association between soluble adhesion molecules levels and retinopathy in type 2 diabetic patients. Levels of soluble E-selectin, ICAM-1 and VCAM-1 were measured by enzyme-linked immunosorbent assay (ELISA) in 47 type 2 diabetic patients classified in two subgroups according to the presence (n=34) or absence (n=13) of retinopathy as determined by fundus ophthalmoscopy; 22 control subjects were also studied. Soluble E-selectin levels were significantly elevated in both diabetic subgroups compared to control subjects (p<0.01), while no significant difference was found in sICAM-1 and sVCAM-1 levels. However, sE-selectin, sICAM-1 and sVCAM-1 levels were comparable in diabetic subgroups. The progression of retinopathy was not associated with an increase in soluble adhesion molecules levels. Stepwise multiple regression analysis revealed that only diabetes duration and microalbuminuria were independent determinants of retinopathy (p<0.01). Our results confirm the contribution of endothelial activation in the development of diabetic complications as indicated by increased levels of soluble adhesion molecules. However, a direct implication of adhesion molecules in the pathogenesis or progression of type 2 diabetic retinopathy cannot be supported.

Diabetic patients show lower pulmonary volumes and variation in DLco by changing posture from sitting to supine position, and they also show increased levels of E-selectin. A possible explanation is impaired pulmonary microvasculature, because adhesion molecules seem to be sensitive markers of endothelial activation and damage seen in diabetes.

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