Related Experiment Videos
Heterogeneous nature of microalbuminuria in NIDDM: studies of endothelial function and renal structure
P Fioretto1, C D Stehouwer, M Mauer
1Department of Internal Medicine and Center for the Study of Aging, National Research Council, University of Padova, Italy.
Abstract:
Microalbuminuria (MA) is associated with microangiopathy (renal and retinal lesions) in insulin-dependent diabetic (IDDM) patients. In contrast MA does not reflect microvascular damage in a substantial number of non-insulin-dependent diabetic (NIDDM) patients. MA predicts cardiovascular disease in NIDDM patients with increased von Willebrand factor (vWF) plasma levels which are hypothesized to reflect endothelial dysfunction. However, it is not known whether MA is consequent to generalised endothelial dysfunction or to renal injury. Thus, this study evaluated vWF plasma levels in relation to renal and retinal structural abnormalities in NIDDM patients with MA. Kidney biopsies, fundoscopy and measures of vWF plasma levels were performed in 32 NIDDM patients with MA. These patients were allocated to two renal structural categories: A) Without renal structural abnormalities (C I, n = 10): normal or near-normal renal structure, and B) With renal structural abnormalities (n = 22), further divided into: C II (n = 12) with typical diabetic nephropathology, predominantly glomerulopathy, and C III (n = 10) with atypical patterns of renal injury (more advanced tubulo-interstitial and arteriolar than glomerular changes). vWF plasma levels were significantly higher in category B (C II: 195+/-49% and C III: 161+/-46%) than in category A (C I: 119+/-42%), (chi-square, p < 0.05). Diabetic retinopathy was also related to vWF plasma levels (ANOVA, p < 0.05). These data suggest that there are two types of MA in NIDDM: one associated with increased vWF levels, established renal injury and frequently retinopathy, and the other characterized by normal vWF levels, normal renal structure and absent or mild diabetic retinopathy. We propose that vWF plasma levels in NIDDM patients with MA may help to identify patients with important renal structural changes, increased retinopathy risk and, perhaps, generalised endothelial dysfunction. Whether vWF plasma levels predict end-stage renal disease and cardiovascular events deserves longitudinal studies.
Insights
Microalbuminuria in non-insulin-dependent diabetes has two forms: one linked to kidney damage and retinopathy, indicated by elevated von Willebrand factor (vWF) levels, and another with normal vWF and renal structure.
Area of Science:
- Endocrinology
- Nephrology
- Vascular Biology
Background:
- Microalbuminuria (MA) in non-insulin-dependent diabetes (NIDDM) can predict cardiovascular disease, potentially linked to endothelial dysfunction indicated by elevated von Willebrand factor (vWF).
- It remains unclear if MA in NIDDM stems from generalized endothelial dysfunction or specific kidney injury.
Purpose of the Study:
- This study aimed to investigate the relationship between vWF plasma levels and renal and retinal structural abnormalities in NIDDM patients with MA.
Main Methods:
- 32 NIDDM patients with MA underwent kidney biopsies, fundoscopy, and vWF plasma level measurements.
- Patients were categorized based on renal structural abnormalities: Category A (normal/near-normal), Category B (with abnormalities, including typical diabetic nephropathology and atypical injury patterns).
Main Results:
- vWF plasma levels were significantly higher in patients with renal structural abnormalities (Category B) compared to those without (Category A).
- Diabetic retinopathy was also significantly associated with higher vWF plasma levels.
- Two distinct types of MA in NIDDM were identified: one associated with elevated vWF, renal injury, and retinopathy, and another with normal vWF and renal structure.
Conclusions:
- vWF plasma levels may help identify NIDDM patients with MA who have significant renal structural changes, increased retinopathy risk, and potential generalized endothelial dysfunction.
- Further longitudinal studies are needed to determine if vWF levels predict end-stage renal disease and cardiovascular events.