Adrenal changes in Niemann-Pick disease: differences between sphingomyelinase deficiency and type C

Area of Science:

• Biochemistry
• Pathology
• Genetics

Background:

• Niemann-Pick disease (NPD) is a group of inherited metabolic disorders.
• Adrenal gland involvement varies significantly across NPD subtypes.
• Understanding tissue-specific storage is crucial for NPD diagnosis and management.

Purpose of the Study:

• To compare adrenal tissue storage in sphingomyelinase (SMase) deficiency and Niemann-Pick type C.
• To elucidate the distinct structural and chemical alterations in adrenal glands for each NPD type.
• To investigate the cellular localization and biochemical characteristics of lipid storage.

Main Methods:

• Structural, chemical, and histochemical analyses of adrenal tissue.
• Electron microscopy for fine structural examination.
• Lipid histochemistry and enzymatic activity assays.

Main Results:

• SMase deficiency: Pronounced sphingomyelin (SM) storage in cortical epithelium, foamy transformation, reduced lipofuscin, and stromal macrophage/endothelial storage.
• Type C: Macroscopically normal adrenals with focal stromal foam cells, minimal phospholipid and glycosphingolipid increase, and rudimentary cortical storage distinct from SMase deficiency.
• No medullary storage observed in either group.

Conclusions:

• Adrenal glands exhibit striking quantitative and qualitative differences in storage between SMase deficiency and Niemann-Pick type C.
• Cortical epithelium in type C is remarkably resistant to the metabolic disorder.
• Findings underscore the heterogeneity of lipid storage in NPD and its tissue-specific manifestations.