Glomerular structure and function in diabetic nephropathy. Early to advanced stages.

Area of Science:

• Nephrology
• Diabetology
• Pathology

Background:

• Insulin-dependent diabetes mellitus (IDDM) frequently leads to diabetic nephropathy.
• Persistent albuminuria is a key indicator of kidney damage in diabetic patients.
• Understanding the relationship between clinical parameters and kidney structure is crucial for managing diabetic kidney disease.

Purpose of the Study:

• To investigate the correlation between clinical markers of kidney function and structural changes in kidney biopsies of diabetic patients.
• To assess the relationship between urinary albumin excretion (UAE), glomerular filtration rate (GFR), blood pressure (BP), and histological features of diabetic nephropathy.

Main Methods:

• Kidney biopsies from 14 patients with IDDM and persistent albuminuria were analyzed using light and electron microscopy.
• Clinical parameters including UAE, GFR, and BP were measured.
• Structural lesions such as basement membrane (BM) thickness, mesangial expansion, and glomerular occlusion were quantified.

Main Results:

• The overall severity of clinical nephropathy correlated significantly with structural lesions (r=0.62, 2P<0.05).
• GFR showed a strong correlation with glomerular filtration surface (FS) (r=0.72, 2P=0.004).
• UAE correlated with the percentage of BM surface showing specific fine structure alterations (r=0.62, 2P=0.02); BP did not correlate with structural parameters.

Conclusions:

• Clinical indicators of diabetic nephropathy severity are closely linked to specific structural changes in the glomeruli.
• Compensatory changes in glomerular capillaries occur, maintaining filtration surface area even with increased mesangial expansion.
• Glomerular volume is influenced by early diabetic hypertrophy and subsequent pathological changes.