Hans-Jacob Bangstad

Glomerular volume and the glomerular vascular pole area in patients with insulin-dependent diabetes mellitus

Abstract The vascular pole area (VPA) and glomerular volume were measured in renal biopsies from 9 insulin-dependent diabetes mellitus (IDDM) patients with normal albumin excretion rate (IDDM group 1), 38 IDDM patients with albumin excretion rate >15 μg/min (IDDM group 2) and 10 living kidney donors (ND). The volume of individual glomeruli was estimated as the sum of profile areas factored by the measured distance between levels, t∼ 10 μm, and VPA as the sum of chords multiplied by t. Mean glomerular volume was increased in IDDM patients but reached statistical significance only in IDDM group 2 (P = 0.002 vs ND). VPA was significantly different among the groups, mean (CV%) was 2036 (29) μm2 in ND, 3555 (34) μm2 in IDDM group 1, and 3528 (48) μm2 in IDDM group 2, p = 0.004 and 0.001, IDDM versus ND. VPA calculated as a percentage of the surface area of the corresponding glomerulus was 2.4 (23)% in ND, 3.4 (27)% in IDDM group 1, and 3.3 (42)% in IDDM group 2; P = 0.007 and 0.01, IDDM versus ND. The intra-biopsy coefficient of variation was high (20–35%) and of the same order in all groups for all three measurements. Glomerular volume and absolute as well as relative size of VPA showed a positive correlation with estimates of mesangial expansion in IDDM group 2 and the VPA showed a negative correlation with GFR. Thus, part of the enlargement may represent a compensatory phenomenon triggered by the development of structural and functional abnormalities in the diabetic kidney.

Renal Structural Changes in Patients with Type 1 Diabetes and Microalbuminuria

Associations between early stages of diabetic nephropathy and structural changes is far from clarified since some reports present rather marked changes in patients in the preclinical stage whereas others found very moderate changes in the early stage of nephropathy. Hence the issue is still a challenge to further studies. This chapter concentrates on the renal morphological changes in patients with Type 1 diabetes and early nephropathy and the possibilities of influencing the progression by blood glucose control and antihypertensive treatment.

Long‐term studies of the juxtaglomerular apparatus in young microalbuminuric type 1 diabetic patients

Aim: To determine the long‐term changes of the juxtaglomerular apparatus in incipient diabetic nephropathy. Methods: Three renal needle biopsies were performed on 15 young type 1 diabetic patients with microalbuminuria; at baseline and after an average of 2.4 and 8.2 years. Using light microscopy, 1 μm serial sections of the plastic‐embedded biopsies were investigated and volumes of the juxtaglomerular apparatus and glomerulus and areas of the macula densa and lumina of the afferent and efferent arterioles were measured. Results: From baseline to second follow‐up there was a significant decrease in JGA relative to glomerular volume. There was an increase in luminal area of the efferent arteriole which was paralleled by (non‐significant) changes in the afferent arteriole. Conclusion: Over a period of 8.2 years JGA size remained stable, but decreased relative to glomerular size. Also, an increase in luminal area was noted in efferent arterioles. This may be due to increased single nephron blood flow secondary to nephron loss.

Glomerular Ultrastructural Changes in Microalbuminuric IDDM-Patients

Since the term »microalbuminuria« (MA) was coined in 1982 [1] elevated albumin excretion rate has been regarded as the best indicator to signal early diabetic nephropathy [2–5]. Two main aspects of renal function at this stage of diabetic nephropathy, are the relation to glomerular structure and the impact of blood glucose control. Improved blood glucose control has been shown to reduce the risk of developing overt nephropathy in patients with MA [6,7] and retard the progression of AER [8], but the concomitant ultrastructural changes were not investigated.