Related Experiment Videos
Early glomerular lesions in amyloidosis. Electronmicroscopic findings
Abstract:
Our investigations on early glomerular changes in renal amyloidosis showed the following: 1. In some renal biopsies, amyloid was demonstrated in the mesangial matrix predominantly and could be seen penetrating through the basement membrane of the mesangial region into the subepithelial space of adjacent glomerular capillaries. 2. In other biopsies, showing the same severity of amyloidosis, deposits were demonstrated in the mesangium and in the capillary walls distant from the mesangium on both sides of the basement membrane. There was no apparent connection between the deposits in these two areas. 3. On the basis of the morphological changes found in the cytoplasm of the mesangial cells, the glomerular epithelial cells and partly also in the endothelial cells, supported by our electron microscopic findings in the immediate vicinity of these cells, we come to the conclusion that amyloid in the glomerulus is formed from amyloid precursors brought via the blood stream. 4. Amyloid fibrils may be formed in the extracellular space of the glomerulus under the influence of lysosomal enzymes released from epithelial, mesangial and perhaps endothelial cells, by action of these enzymes on extracellularly deposited amyloid precursors.
Insights
Early renal amyloidosis involves glomerular amyloid deposits in the mesangium and capillary walls. These deposits originate from blood-borne precursors, with local enzymes potentially aiding fibril formation within the glomerulus.
Area of Science:
- Nephrology
- Pathology
- Cell Biology
Background:
- Renal amyloidosis is characterized by amyloid deposition in kidney tissues.
- Understanding early glomerular changes is crucial for diagnosing and managing renal amyloidosis.
Purpose of the Study:
- To investigate the initial morphological alterations in glomeruli during renal amyloidosis.
- To elucidate the origin and formation process of amyloid within the glomerulus.
Main Methods:
- Analysis of renal biopsies using light and electron microscopy.
- Morphological examination of mesangial, epithelial, and endothelial cells.
Main Results:
- Amyloid deposits were observed predominantly in the mesangial matrix, extending into subepithelial spaces.
- In some cases, deposits were found in both mesangium and capillary walls, seemingly independent.
- Morphological changes suggested intracellular processing of amyloid precursors within glomerular cells.
Conclusions:
- Amyloid in the glomerulus originates from circulating amyloid precursors.
- Local glomerular cells, via lysosomal enzymes, may contribute to amyloid fibril formation extracellularly.