Plasma homocysteine, oxidative stress and endothelial function in patients with Type 1 diabetes mellitus and microalbuminuria

• Published in: Diabetic medicine 2006-12, Vol.23 (12), p.1350-1356
• Main Authors: Wotherspoon, F., Laight, D. W., Browne, D. L., Turner, C., Meeking, D. R., Allard, S. E., Munday, L. J., Shaw, K. M., Cummings, M. H.
• Format: Article
• Language: English
• Subjects: Adult; Albuminuria - etiology; Albuminuria - metabolism; Biological and medical sciences; Case-Control Studies; Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - physiopathology; Diabetes. Impaired glucose tolerance; Diabetic Angiopathies - blood; Diabetic Angiopathies - physiopathology; Diabetic Nephropathies - blood; Diabetic Nephropathies - physiopathology; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; endothelium; Endothelium, Vascular - physiopathology; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; homocysteine; Homocysteine - metabolism; Humans; Male; Medical sciences; Nephrology. Urinary tract diseases; Oxidative Stress; Type 1 diabetes mellitus; Urinary system involvement in other diseases. Miscellaneous; Urinary tract. Prostate gland; vascular disease
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/j.1464-5491.2006.01980.x

Aims  The purpose of this study was to examine the associations between endothelial function, plasma homocysteine and oxidative stress in patients with Type 1 diabetes mellitus (DM) and microalbuminuria compared with DM patients with normoalbuminuria and non‐diabetic control subjects. We wished to test the hypothesis that increased cardiovascular risk in patients with Type 1 diabetes and microalbuminuria may be in part as a result of hyperhomocysteinaemia‐mediated oxidative stress leading to impaired endothelial function. Methods  We measured forearm blood flow, total plasma homocysteine, total antioxidant status (TAOS) and whole blood glutathione in 31 DM patients, 16 with microalbuminuria and 15 with normoalbuminuria, and 15 non‐diabetic control subjects. Results  Plasma homocysteine levels were significantly higher in the microalbuminuric diabetic patients compared with the normoalbuminuric patients and the control subjects. TAOS was significantly lower in the micoalbuminuric and normoalbuminuric diabetic patients compared with the control subjects, although TAOS levels were similar in both groups of diabetic patients. There was no difference in forearm blood flow between the groups and no association between measured endothelial function and antioxidant defence/oxidative stress and homocysteine in each group. There was no association between plasma total homocysteine and TAOS or whole blood glutathione within the groups. Conclusions  We have found mild hyperhomocysteinaemia in microalbuminuric DM patients compared with normoalbuminuric DM patients and non‐diabetic subjects and some evidence for reduced antioxidant defence in DM patients. These findings add to our understanding of the increased risk of vascular disease in patients with Type 1 diabetes.