[The juxtaglomerular apparatus in chronic glomerulonephritis]

Area of Science:

• Nephrology
• Pathology
• Electron Microscopy

Background:

• The juxtaglomerular apparatus (JGA) plays a crucial role in regulating blood pressure and renal function.
• Morphological changes in the JGA are implicated in the pathogenesis of various kidney diseases, including glomerulonephritis.
• Understanding JGA alterations in glomerulonephritis is essential for elucidating disease mechanisms and potential therapeutic targets.

Purpose of the Study:

• To conduct a qualitative and quantitative morphological evaluation of the juxtaglomerular apparatus (JGA).
• To examine JGA morphology in renal biopsies from patients with mesangio-proliferative and mesangiocapillary glomerulonephritis.
• To investigate the relationship between JGA morphology, hypertension, proteinuria, and disease duration.

Main Methods:

• Electron microscopic examination of renal biopsies.
• Qualitative and quantitative morphological analysis of the juxtaglomerular apparatus (JGA).
• Analysis of granule formation and cell types within the JGA.

Main Results:

• An increased total number of JGA cells, including granular cells, was observed in chronic glomerulonephritis.
• In hypertensive glomerulonephritis with high proteinuria, rhomboidal protogranules predominated in epithelioid cells.
• In normotensive glomerulonephritis with marked proteinuria, spherical and lipofuscin-like granules were predominant.
• A significant predominance of elongated granules (rhomboidal protogranules) was found in JGA epithelioid cells in hypertensive glomerulonephritis.
• A strong association was demonstrated between the degree of JGA activation and disease duration.
• Increased JGA cellularity correlated with heightened glomerular mesangial cell activity and afferent arteriolar epithelioid cell presence.
• Dystrophic changes in adrenergic nerves were noted, potentially linked to nervous system overcharge in hypertension.

Conclusions:

• Chronic glomerulonephritis is associated with an increase in juxtaglomerular apparatus (JGA) cell numbers.
• Hypertension significantly influences the morphology of granules within JGA epithelioid cells.
• JGA activation is strongly correlated with disease duration in glomerulonephritis.
• Alterations in JGA morphology and associated nerve changes may reflect the impact of hypertension on renal function.