Spontaneous, Experimentally Induced, and Transmissible AA Amyloidosis in Japanese Quail ( Coturnix japonica)

Systemic AL kappa chain amyloidosis in a captive Bornean orangutan (Pongo pygmaeus)

Systemic amyloid light-chain (AL) amyloidosis is an infrequent disease in which amyloid fibrils derived from the immunoglobulin light chain are deposited in systemic organs, resulting in functional impairment. This disease has been notably uncommon in animals, and nonhuman primates have not been reported to develop it. In this study, we identified the systemic AL kappa chain amyloidosis in a captive Bornean orangutan (Pongo pygmaeus) and analyzed its pathogenesis. Amyloid deposits were found severely in the submucosa of the large intestine, lung, mandibular lymph nodes, and mediastinal lymph nodes, with milder lesions in the liver and kidney. Mass spectrometry-based proteomic analysis revealed an abundant constant domain of the immunoglobulin kappa chain in the amyloid deposits. Immunohistochemistry further confirmed that the amyloid deposits were positive for immunoglobulin kappa chains. In this animal, AL amyloidosis resulted in severe involvement of the gastrointestinal submucosa and lymph nodes, which is consistent with the characteristics of AL amyloidosis in humans, suggesting that AL amyloid may have a similar deposition mechanism across species. This report enhances the pathological understanding of systemic AL amyloidosis in animals by providing a detailed characterization of this disease based on proteomic analysis.

Histological evaluation of the distribution of systemic AA-amyloidosis in nine domestic shorthair cats

Amyloidosis is a group of protein-misfolding disorders characterized by the accumulation of amyloid in organs, both in humans and animals. AA-amyloidosis is considered a reactive type of amyloidosis and in humans is characterized by the deposition of AA-amyloid fibrils in one or more organs. In domestic shorthair cats, AA-amyloidosis was recently reported to be frequent in shelters. To better characterize this pathology, we report the distribution of amyloid deposits and associated histological lesions in the organs of shelter cats with systemic AA-amyloidosis. AA-amyloid deposits were identified with Congo Red staining and immunofluorescence. AA-amyloid deposits were then described and scored, and associated histological lesions were reported. Based on Congo Red staining and immunofluorescence nine shelter cats presented systemic AA-amyloidosis. The kidney (9/9), the spleen (8/8), the adrenal glands (8/8), the small intestine (7/7) and the liver (8/9) were the organs most involved by amyloid deposits, with multifocal to diffuse and from moderate to severe deposits, both in the organ parenchyma and/or in the vascular compartment. The lung (2/9) and the skin (1/8) were the least frequently involved organs and deposits were mainly focal to multifocal, mild, vascular and perivascular. Interestingly, among the organs with fibril deposition, the stomach (7/9), the gallbladder (6/6), the urinary bladder (3/9), and the heart (6/7) were reported for the first time in cats. All eye, brain and skeletal muscle samples had no amyloid deposits. An inflammatory condition was identified in 8/9 cats, with chronic enteritis and chronic nephritis being the most common. Except for secondary cell compression, other lesions were not associated to amyloid deposits. To conclude, this study gives new insights into the distribution of AA-amyloid deposits in cats. A concurrent chronic inflammation was present in almost all cases, possibly suggesting a relationship with AA-amyloidosis.

Pathological Characterization of Spontaneous AA Amyloidosis in Microminipigs

The minipig has been used as a non-rodent species in nonclinical toxicology studies, but little is known about amyloid A (AA) amyloidosis in this species. Among domestic pigs, reports of AA amyloidosis have been limited to animals with mutations in the N-terminal residue of serum AA (SAA), which is thought to be a primary etiological factor. In this study, we histologically examined 26 microminipigs aged 0.6 to 10 years and observed amyloid deposition in one 0.6-year-old and six 5-year-old or older microminipigs. The amyloid deposits were identified as AA based on mass spectrometry (MS) and immunohistochemistry (IHC). The 0.6-year-old microminipig showed severe deposition in the renal cortex and spleen, whereas 5-year-old or older animals had severe deposition in the renal medulla. MS and IHC detected serum amyloid P-component (SAP) in amyloid deposits in older animals but not in a 0.6-year-old animals. Based on the proteomic analysis and gene sequencing, amino acid mutations of SAA, previously found in domestic pigs, were not involved in the pathogenesis of AA amyloidosis in microminipigs. This study demonstrates that microminipigs with wild-type SAA develop AA amyloidosis and presents the possibility that differences in the environment surrounding amyloid, such as SAP, may influence differences in the pathological phenotype.

Aggregation of Mouse Serum Amyloid A Protein Was Promoted by Amyloid-Enhancing Factors with the More Genetically Homologous Serum Amyloid A

Amyloid A (AA) amyloidosis is a condition in which amyloid fibrils characterized by a linear morphology and a cross-β structure accumulate and are deposited extracellularly in organs, resulting in chronic inflammatory diseases and infections. The incidence of AA amyloidosis is high in humans and several animal species. Serum amyloid A (SAA) is one of the most important precursor amyloid proteins and plays a vital step in AA amyloidosis. Amyloid enhancing factor (AEF) serves as a seed for fibril formation and shortens the onset of AA amyloidosis sharply. In this study, we examined whether AEFs extracted and purified from five animal species (camel, cat, cattle, goat, and mouse) could promote mouse SAA (mSAA) protein aggregation in vitro using quantum-dot (QD) nanoprobes to visualize the aggregation. The results showed that AEFs shortened and promoted mSAA aggregation. In addition, mouse and cat AEFs showed higher mSAA aggregation-promoting activity than the camel, cattle, and goat AEFs. Interestingly, homology analysis of SAA in these five animal species revealed a more similar amino acid sequence homology between mouse and cat than between other animal species. Furthermore, a detailed comparison of amino acid sequences suggested that it was important to mSAA aggregation-promoting activity that the 48th amino acid was a basic residue (Lys) and the 125th amino acid was an acidic residue (Asp or Glu). These data imply that AA amyloidosis exhibits higher transmission activity among animals carrying genetically homologous SAA gene, and may provide a new understanding of the pathogenesis of amyloidosis.

AA Amyloid Deposition in the Central and Peripheral Nervous Systems in Flamingos

AA amyloidosis is characterized by amyloid deposition in systemic organs, but amyloid deposition in the central nervous system (CNS) or peripheral nervous system (PNS) is rare. In this study, AA amyloidosis was observed in 31 of 48 flamingos that died at a Japanese zoo. Almost all cases developed AA amyloidosis secondary to inflammatory diseases such as enteritis. Affected flamingos had AA amyloid deposition around blood vessels in periventricular white matter of the brain and in peripheral nerves. In addition, cerebral Aβ amyloidosis was observed in one of the 31 cases with AA amyloidosis. In conclusion, flamingos in the zoo commonly developed systemic amyloidosis with frequent amyloid deposition in the CNS and PNS, which seems to be a unique distribution in this avian species. Comparative pathological analyses in flamingos may help elucidate the pathogenesis of amyloid neuropathy.

Needle-shaped amyloid deposition in rat mammary gland: evidence of a novel amyloid fibril protein

Amyloidosis is an extremely rare event in rats. In this study, we report that lipopolysaccharide binding protein (LBP) is the most likely amyloidogenic protein in rat mammary amyloidosis. Histologically, corpora amylacea (CA) and stromal amyloid (SA) were observed in rat mammary glands, and needle-shaped amyloid (NA) was also observed on the surface or gap of CA and SA. Following surveillance in aged rats, NA was observed in 62% of mammary tumours, 25% of male mammary glands and 83% of female mammary glands. Proteomic analysis showed that lactadherin was a major constitutive protein of CA and SA, and both were positive following immunohistochemistry with anti-lactadherin antibodies. In the same analysis, LBP was detected as a prime candidate protein in NA, and NA was positive following immunohistochemistry and immunoelectron microscopy with anti-LBP antibody. Furthermore, synthetic peptides derived from rat LBP formed amyloid fibrils in vitro. Overall, these results provide evidence that LBP is an amyloid precursor protein of NA in rat mammary glands.

Multicystic peritoneal tumor in two layer hens

In chicken, peritoneal cystic lesions have not been clearly categorized. In this study, diffuse peritoneal multiple cysts were observed in two layer hens. The cysts in the serosa were lined with single layers of squamous or cuboidal cells. The papillary proliferations of columnar cells were also observed in one case. The smooth muscle layer or mass were observed around the cysts in both cases. The cystic lining cells were positive for pan-cytokeratin, vimentin, S100 and Wilms tumor 1. Ultrastructurally, they had sparsely microvilli on the luminal surface. The histological results indicated the present cases were multicystic mesothelioma, but also had characteristics of Mullerian epithelium. This is the first report describing the detailed pathological feature of unique multicystic tumor in chicken.

Experimental model of oral transmissible AA amyloidosis in quails

In poultry and zoo birds, mass outbreaks of amyloid A (AA) amyloidosis are often reported, and horizontal transmission is considered as one of the causes. However, oral transmission of avian AA amyloidosis in nature has been unclear. In order to clarify the horizontal transmission of avian AA amyloidosis, basic research using an appropriate oral transmission model is necessary. In this study, we developed an oral transmission model of AA amyloidosis using quails, and assessed the oral transmission efficiency of AA amyloidosis in quails and mice. Young quails, adult quails, and young mice received inflammatory stimulation with lipopolysaccharide; simultaneously, homogeneous amyloid fibrils were orally or intravenously administered. By histological examination, induction of amyloidosis by oral or intravenous administration of amyloid was confirmed in all species. Furthermore, both quail and murine AA amyloidosis were orally transmitted in a dose-dependent manner. These results support the possibility of horizontal transmission of avian AA amyloidosis in nature. This model will be able to contribute to the elucidation of spontaneous horizontal transmission of avian AA amyloidosis in the future. RESEARCH HIGHLIGHTS Quail AA amyloidosis was orally transmitted in a dose-dependent manner. Oral transmission was less efficient than intravenous transmission. In-cage horizontal transmission did not occur during 4-week cohabitation. Amyloid deposition in tissues of quail was grossly visible.

Pleomorphic Malignant Mesothelioma in a Broiler Breeder Infected with Avian Leucosis Virus Subgroup J

Avian leucosis virus (ALV) is an oncogenic retrovirus that induces tumours including lymphoid leucosis and myeloid leucosis. Pleomorphic malignant mesothelioma and myelocytoma, which were thought to be induced by ALV subgroup J (ALV-J) infection, were identified in a 432-day-old broiler breeder. The bird showed no clinical signs; however, at necropsy examination there were multiple nodules in the alimentary tract. Microscopical analysis showed that these consisted of pleomorphic cells and myelocyte-like cells. Immunohistochemistry revealed that the pleomorphic cells were atypical and expressed cytokeratin, vimentin, c-kit, calretinin and ALV. The myelocyte-like cells were also positive for ALV. Retroviral type C particles were observed by electron microscopy. ALV-E and ALV-J nucleotide sequences were detected in DNA extracted from formalin-fixed and paraffin wax-embedded small intestinal tissue. Based on these results, the tumours were diagnosed as pleomorphic malignant mesothelioma and myelocytoma and were thought to have been induced by ALV-J infection. This is the first report of malignant mesothelioma associated with naturally acquired ALV-J infection.