Related Experiment Videos
Early lesions of the nephron in paraproteinemia
Abstract:
Electron microscopy of renal biopsies in eight patients with paraproteinemia (six multiple myeloma, one Waldenström's disease, one idiopathic paraproteinemia) and without impairment of renal function demonstrates an increase of mesangial matrix and thickening of the lamina rara interna of the basement membrane in the glomerulus by fibrillar material without periodicity. These lesions are thought to exhibit precursors of amyloid deposits. The proximal tubules show signs of increased cellular activity probably because of handling an increased protein load. In the basement membranes there are proteins with a fibrillar structure and definite periodicity. These are suggested to be consistent with large aggregates of immunoglobulin fragments.
Insights
Electron microscopy revealed fibrillar material in kidney biopsies of patients with paraproteinemia, suggesting early amyloid deposit precursors and immunoglobulin fragments in renal basement membranes.
Area of Science:
- Nephrology
- Pathology
- Immunology
Background:
- Paraproteinemia, including multiple myeloma and Waldenström's disease, can affect kidney function.
- Renal biopsies are crucial for diagnosing and understanding kidney pathologies associated with paraproteinemia.
Purpose of the Study:
- To investigate the ultrastructural renal changes in patients with paraproteinemia and normal renal function.
- To identify the nature of deposits in the glomeruli and tubules using electron microscopy.
Main Methods:
- Electron microscopy was performed on renal biopsies from eight patients with paraproteinemia.
- Patients had no impairment of renal function at the time of biopsy.
Main Results:
- Glomeruli showed increased mesangial matrix and thickened basement membranes with non-periodic fibrillar material, indicative of amyloid precursor lesions.
- Proximal tubules exhibited increased cellular activity, likely due to handling increased protein load.
- Renal basement membranes contained fibrillar proteins with periodicity, consistent with immunoglobulin fragments.
Conclusions:
- The observed ultrastructural lesions in paraproteinemic kidneys may represent early stages of amyloid deposition.
- Fibrillar proteins in basement membranes are likely aggregates of immunoglobulin fragments, reflecting the underlying paraproteinemia.