Urinary glycosaminoglycan and proteoglycan excretion in normoalbuminuric patients with type 1 diabetes mellitus

J Nephrol. 2002 May-Jun;15(3):290-6.


Background: Diabetic nephropathy may be related to an abnormal metabolism of glycosaminoglycans (GAG) in the glomerular basement membrane (GBM). The first manifestation of nephropathy is microalbuminuria, whose appearance indicates a loss of GBM selectivity. The present study evaluated whether GAG excretion becomes abnormal in parallel with microalbuminuria, and whether such abnormalities are also present in normoalbuminuric diabetic patients.

Methods: We measured urinary GAG excretion in 60 patients with type 1 (insulin-dependent) diabetes mellitus and in 22 healthy subjects. GAG were isolated from 24-h urine using ion-exchange chromatography on DEAE Sephacel. GAG composition was determined by cellulose acetate electrophoresis and expressed as percentages by densitometric scanning of Alcian Blue stained strips.

Results: On subgrouping for albuminuric status and glyco-metabolic control, we found high urinary GAG concentrations in all except the normoalbuminuric patients with good glyco-metabolic control. The urinary GAG electrophoretic pattern showed alterations in chondroitin sulphate (CS) and heparan sulphate (HS) relative contents. A higher frequency of low sulphated chondroitin sulphate-proteoglycan (LSC-PG) was observed in all patients, including those with normoalbuminuria and good glyco-metabolic control.

Conclusions: This urinary pattern may be indicative of an abnormal GBM metabolism. Since GAG play an important role in GBM permeability, these anomalies might consequently represent a first step towards selective changes of GBM in type 1 diabetes mellitus.

MeSH terms

  • Adult
  • Albuminuria / complications*
  • Albuminuria / physiopathology
  • Albuminuria / urine*
  • Basement Membrane / physiopathology
  • Creatinine / urine
  • Diabetes Mellitus, Type 1 / complications*
  • Diabetes Mellitus, Type 1 / physiopathology
  • Diabetes Mellitus, Type 1 / urine*
  • Diabetic Nephropathies / etiology*
  • Diabetic Nephropathies / physiopathology
  • Diabetic Nephropathies / urine*
  • Female
  • Follow-Up Studies
  • Glycosaminoglycans / urine*
  • Humans
  • Male
  • Outcome Assessment, Health Care
  • Predictive Value of Tests
  • Proteoglycans / urine*
  • Risk Factors
  • Severity of Illness Index
  • Time Factors


  • Glycosaminoglycans
  • Proteoglycans
  • Creatinine