BACKGROUND: The Steno hypothesis postulates that a genetic defect in the regulation of the production of heparan sulphate by renal and non-renal cells determines susceptibility for the development of proteinuria and macro-angiopathy in patients with diabetic nephropathy (DN). METHODS: To test this hypothesis, skin fibroblasts isolated from type II diabetic patients with overt DN, micro-albuminuria, or without DN and from non-diabetic patients (n=8 for each group) were cultured in the presence of 5 or 25 mM D-glucose or in 25 mM L-glucose, and tested for the expression of N-deacetylase/N-sulphotransferase (NDST) 1 and 2 by semi-quantitative RT--PCR. Proteoglycan production was measured by means of metabolic labelling. RESULTS: In each group of patients, 25 mM D-glucose significantly reduced the incorporation of [3H]glucosamine (P<0.01), but not [35S]sulphate. The quantity of NDST 1 mRNA expression did not differ between the four groups. In the non-diabetic group only, 25 mM D-glucose significantly increased NDST 1 mRNA expression (P<0.01). In contrast, NDST 2 mRNA expression was reduced by 25 mM D-glucose in all groups (P<0.01). In the diabetic patients, NDST 2 mRNA was significantly reduced compared with the non-diabetic patients. No differences were found between patients with or without nephropathy. In mesangial cells (MC), NDST expression was not influenced by glucose. CONCLUSIONS: Since NDST 1 and 2 are not differentially expressed in patients with or without nephropathy and, in MC, the mRNA expression hereof is not influenced by glucose as in skin fibroblasts, our data do not support the Steno hypothesis.
BACKGROUND: The Steno hypothesis postulates that a genetic defect in the regulation of the production of heparan sulphate by renal and non-renal cells determines susceptibility for the development of proteinuria and macro-angiopathy in patients with diabetic nephropathy (DN). METHODS: To test this hypothesis, skin fibroblasts isolated from type II diabeticpatients with overt DN, micro-albuminuria, or without DN and from non-diabeticpatients (n=8 for each group) were cultured in the presence of 5 or 25 mM D-glucose or in 25 mM L-glucose, and tested for the expression of N-deacetylase/N-sulphotransferase (NDST) 1 and 2 by semi-quantitative RT--PCR. Proteoglycan production was measured by means of metabolic labelling. RESULTS: In each group of patients, 25 mM D-glucose significantly reduced the incorporation of [3H]glucosamine (P<0.01), but not [35S]sulphate. The quantity of NDST 1 mRNA expression did not differ between the four groups. In the non-diabetic group only, 25 mM D-glucose significantly increased NDST 1 mRNA expression (P<0.01). In contrast, NDST 2 mRNA expression was reduced by 25 mM D-glucose in all groups (P<0.01). In the diabeticpatients, NDST 2 mRNA was significantly reduced compared with the non-diabeticpatients. No differences were found between patients with or without nephropathy. In mesangial cells (MC), NDST expression was not influenced by glucose. CONCLUSIONS: Since NDST 1 and 2 are not differentially expressed in patients with or without nephropathy and, in MC, the mRNA expression hereof is not influenced by glucose as in skin fibroblasts, our data do not support the Steno hypothesis.
Authors: Terrel Sugar; Deborah J Wassenhove-McCarthy; A Wayne Orr; Jonette Green; Toin H van Kuppevelt; Kevin J McCarthy Journal: Am J Physiol Renal Physiol Date: 2016-03-02