Iatrogenic, insulin-dependent, local amyloidosis

Area of Science:

• Biochemistry
• Pathology
• Endocrinology

Background:

• Amyloidosis involves protein deposits in tissues.
• Localized amyloidosis can arise from external factors.

Purpose of the Study:

• To investigate iatrogenic local amyloidosis.
• To determine if insulin administration can cause in vivo amyloid formation.

Main Methods:

• Histological examination of subcutaneous tissue from a diabetic patient and Wistar rats.
• Congo red staining and polarized light microscopy.
• Immunohistochemistry and electron microscopy.

Main Results:

• Granulation tissue and extracellular deposits were observed at the insulin infusion site.
• Deposits showed green birefringence, indicating amyloid.
• Immunohistochemistry confirmed anti-insulin antibody binding.
• Electron microscopy revealed spear-like amyloid fibrils (60-80 A diameter).

Conclusions:

• Iatrogenically administered insulin can induce localized amyloidosis in vivo.
• Insulin has the potential to form amyloid fibrils both in vitro and in vivo.