Clinicopathological features in ovine AA amyloidosis.

This paper describes the clinicopathological findings in sheep with AA amyloidosis. Serum samples from 12 AA amyloid-affected sheep and urine samples from 5 of these ewes were analyzed. In sera, the most important alteration was reflected in hypoalbuminemia, high concentration in beta and gamma-globulins and high levels of serum BUN, phosphorous and potassium. Serum creatinine, cholesterol and calcium concentrations showed no alterations. Urinary analysis showed proteinuria and a high protein/creatinine ratio. In three urine samples, high activities of urinary enzymes gamma-glutamyl transferase (GGT), beta-glucuronidase (GRS) and N-acetyl-beta-D-glucosaminidase (NAG) were observed, their ratios with urinary creatinine being increased for GGT and NAG and decreased for GRS. In conclusion, important alterations in biochemical and urinary parameters were observed in ovine affected by systemic AA amyloidosis. Those related to the activities of urinary enzymes could constitute reliable parameters for assessing renal injury in ovine AA amyloidosis.

Pathology of AA amyloidosis in domestic sheep and goats.

We describe the main pathologic changes in small ruminants affected by AA amyloidosis, together with the partial sequence of the protein involved. Twenty-one sheep and one goat were selected for presenting macroscopic kidney lesions compatible with systemic amyloidosis. Available tissue samples were studied by histologic, immunopathologic, and ultrastructural means. Renal lesions were characterized grossly by pale cortical surfaces with scattered, miliary, whitish-yellow foci and on cut cortical surfaces by straight, whitish-yellow striations. Gangrenous pneumonia was observed in 16 out of 21 affected sheep (76.2%), although other chronic inflammations were also observed. Amyloid was detected in all grossly affected kidneys using Congo red staining, lesions being most remarkable in glomeruli, affecting 95.5% of animals studied. Congophilic deposits were also observed in intertubular interstitium (68.2%) and medulla (57.1%). All amyloid-affected animals presented proximal convoluted tubule lesions, mostly characterized by an increase in diameter and by hyaline granular degeneration that were responsible for the macroscopic appearance of the kidney. Histologically, amyloid was also seen in blood vessels, spleen, liver, lymph nodes, gastrointestinal tract, and adrenal glands. All amyloid deposits demonstrated greenish-yellow birefringence with polarized light, and the antisera prepared against goat amyloid extracts specifically reacted with birefringent congophilic deposits of both sheep and goats. Ultrastructurally, these deposits were formed by masses of straight, nonbranching fibrils located predominantly in the basement membranes of glomerular capillaries and in the mesangium. Partial sequence of the protein in sheep and goats indicated a high degree of homology with the previously reported sequence of sheep Serum Amyloid A.