alcian-blue and Albuminuria

The Steno hypothesis states that changes in basement membrane anionic charge leads to diabetic microvascular complications. In diabetic nephropathy, loss of basement membrane glycosaminoglycans and the association between glomerular basement membrane heparan sulphate and proteinuria has been documented. A correlation between erythrocyte surface and the glomerular capillary wall charges has also been observed. The aim of this study is to evaluate the relationship between retinopathy and erythrocyte anionic charge and urinary glycosaminoglycan excretion in type 2 diabetic patients.. 49 subjects (58 +/- 7 yrs, M/F 27/22) with type 2 diabetes with proliferative retinopathy (n = 13), nonproliferative retinopathy (n = 13) and without retinopathy (n = 23) were included in the study. 38 healthy subjects were selected as control group (57 +/- 5 yrs, M/F 19/19). Erythrocyte anionic charge (EAC) was determined by the binding of the cationic dye, alcian blue. Urinary glycosaminoglycan and microalbumin excretion were measured.. EAC was significantly decreased in diabetic patients with retinopathy (255 +/- 30 ng alcian blue/10(6) RBC, 312 +/- 30 ng alcian blue/10(6) RBC for diabetic and control groups respectively, p < 0.001). We did not observe an association between urinary GAG and microalbumin excretion and diabetic retinopathy. EAC is found to be negatively correlated with microalbuminuria in all groups.. We conclude that type 2 diabetic patients with low erythrocyte anionic charge are associated with diabetic retinopathy. Reduction of negative charge of basement membranes may indicate general changes in microvasculature rather than retinopathy. More prospective and large studies needs to clarify the role of glycosaminoglycans on progression of retinopathy in type 2 diabetic patients.

Topics: Albuminuria; Alcian Blue; Anions; Blood Glucose; Coloring Agents; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythrocyte Membrane; Female; Glycosaminoglycans; Humans; Male; Middle Aged; N-Acetylneuraminic Acid

The hallmark of renal diseases involving the glomerulus is the presence of proteinuria. While the routes of pathogenesis of proteinuria have not been established, alterations in the barrier function of the glomerular basement membrane (GBM) have been implicated. We evaluated the effect of streptozotocin diabetes and passive Heymann nephritis (PHN) over time on the macromolecular composition of rat GBM to determine if changes in composition correlate with proteinuria. Six to twelve rats from each group (control, diabetic, and PHN) were sacrificed 1, 5, 28, 56, or 84 days after induction of disease. Identical amounts of GBM were subjected to a sequential extraction procedure, and type IV collagen, entactin, laminin, fibronectin, and anionic charge content were quantitated in the extracts. Type IV collagen and entactin content did not change with time or disease. Both laminin and fibronectin contents increased with time in GBM in all groups, but this increase was significantly greater in diabetic GBM. A significant decrease in anionic charge content of GBM coincided with the onset of albuminuria at Day 28 in diabetes, but no change was seen in PHN. In diabetic rats, the increase in laminin content over control preceded the onset of albuminuria, while the increase in fibronectin was not apparent until after albuminuria was present. In PHN, no differences in type IV collagen, entactin, laminin, fibronectin, or anionic charge content of GBM were found compared with control, even though profound albuminuria was evident from Day 5 through 84. Thus, while alterations in laminin and fibronectin content may contribute to the loss of glomerular permselectivity in streptozotocin diabetes, such changes apparently are not involved in PHN.

Topics: Albuminuria; Alcian Blue; Animals; Anions; Basement Membrane; Collagen; Coloring Agents; Diabetes Mellitus, Experimental; Fibronectins; Glomerulonephritis; Kidney Glomerulus; Laminin; Male; Membrane Glycoproteins; Rats; Rats, Sprague-Dawley

Topics: Albuminuria; Alcian Blue; Cadmium; Cadmium Poisoning; Erythrocytes; Humans; Indoles; Retinol-Binding Proteins

The anionic charge on the surface of the erythrocyte and the erythrocyte membrane content of sialic acid and acid glycosaminoglycans (GAGs) were evaluated in insulin-dependent diabetic patients who had albumin excretion rates less than 300 mg/24 h. In these subjects a statistically significant reduction of erythrocyte anionic charge (RBCCh) and GAGs content in erythrocyte ghosts was shown. In view of the demonstration of a negative correlation between RBCCh and albuminuria after a lysine provocative test, these observations support the hypothesis that the onset of microalbuminuria in human diabetes is sustained by an alteration of glomerular charge and consequently of glomerular charge selectivity.

Topics: Adolescent; Adult; Albuminuria; Alcian Blue; Anions; Basement Membrane; Diabetes Mellitus, Type 1; Diabetic Neuropathies; Erythrocyte Membrane; Erythrocytes; Female; Glycosaminoglycans; Humans; Kidney Glomerulus; Male; Middle Aged; Sialic Acids