5-hydroxymethylfurfural and Diabetic-Nephropathies

To evaluate the significance of collagen levels, nonenzymatic glycation, and effective renal plasma flow in diabetes, we studied 52 Streptozocin induced-diabetic rats. After 10 weeks of diabetes, rats were injected i.v. 0.5 microCi/g 99mTechnetium Mercaptoacetyl triglycine and effective renal plasma flow was calculated from the renograms obtained. The collagen content and hydroxymethyl furfural levels of kidney and tail tissue as well as renal plasma flow increased significantly in diabetic rats (p < 0.05). The increase in renal plasma flow indicates that hyperperfusion may play a role in diabetic nephropathy mechanism. The correlation between renal plasma flow and glycation was not as high as the correlations between blood glucose concentrations and hydroxymethyl furfural and collagen levels, suggesting that factors other than glycation are important in increasing the renal plasma flow.

Topics: Animals; Blood Glucose; Collagen; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Furaldehyde; Glycosylation; Kidney; Male; Rats; Rats, Sprague-Dawley; Renal Plasma Flow, Effective

In 18 control subjects and in 41 Type 1 (insulin-dependent) diabetic patients (13 with normal proteinuria, group A; 15 with microproteinuria, group B; and 13 with clinical proteinuria, group C), mean blood glucose, glycosylated haemoglobin and non-enzymatic glycosylated serum and urinary proteins, expressed as 5-hydroxymethylfurfural (5-HMF), were measured. In each group of diabetic patients, the levels of mean daily blood glucose, glycosylated haemoglobin and serum 5-HMF/mg protein were higher than in the control subjects. The urinary 5-HMF/mg proteinuria and the urinary/serum 5-HMF concentration ratio values were raised in group A and reduced in groups B and C. Moreover, they showed a negative correlation with 24-h urinary protein excretion in the control subjects and in each group of diabetic patients. The urinary 5-HMF/day in groups A, B and C was greater than in the control subjects. The urinary 5-HMF/day did not correlate with the mean daily blood glucose levels and, only in group A, did it correlate with serum 5-HMF and glycosylated haemoglobin. This suggests that, in this group, functional factors result in the increased renal elimination of 5-HMF and, therefore, of non-enzymatically glycosylated proteins. However, in the other groups of patients, this elimination depends on the degree of proteinuria.

Topics: Blood Glucose; Blood Proteins; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Diabetic Retinopathy; Furaldehyde; Glycated Hemoglobin; Glycated Serum Proteins; Glycoproteins; Humans; Proteinuria