Skin - Amyloid

Image of amyloid in the skin from a female Swiss CD-1 mouse in a chronic study
Amyloid-accumulations of amorphous, eosinophilic, extracellular material in a female Swiss CD-1 mouse from a chronic study.
Figure 1 of 2
Image of amyloid in the skin from a female Swiss CD-1 mouse in a chronic study
Amyloid-accumulations of amorphous, eosinophilic, extracellular material in a female Swiss CD-1 mouse from a chronic study.
Figure 2 of 2
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comment:

Amyloid deposition ( Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window ) occurs as a result of cells not being able to eliminate insoluble, misfolded protein. It can be associated with overproduction of acute-phase protein in chronic inflammation and is usually associated with systemic amyloidosis. Amyloid deposition is rare in rats but occurs as a common age-related change in some mouse strains, such as Swiss mice (CD-1), and presumably has a genetic predisposition. Amyloid deposition in the skin is almost always seen in the dermis and typically appears as variably sized accumulations of amorphous, eosinophilic, extracellular material that is usually perivascular. Histochemical (e.g., Congo red) and immunohistochemical stains are useful for definitive diagnosis.

recommendation:

Amyloid deposition should be diagnosed and assigned a severity grade whenever present.

references:

Aigelsreiter A, Janig E, Stumptner C, Fuchsbichler A, Zatloukal K, Denk H. 2007. How a cell deals with abnormal proteins. Pathogenetic mechanisms in protein aggregation diseases. Pathobiology 74:145-158.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/17643060

Greaves P. 2007. Integumentary System. In: Histopathology of Preclinical Toxicity Studies. Interpretation and Relevance in Drug Safety Evaluation, 3rd ed. Elsevier, Amsterdam.
Abstract: http://www.sciencedirect.com/science/book/9780444527714

Peckham JC, Heider K. 1999. Skin and subcutis. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 555-612.
Abstract: http://www.cacheriverpress.com/books/pathmouse.htm