A concise review of amyloidosis in animals

Classification of amyloidosis and protein misfolding disorders in animals 2024: A review on pathology and diagnosis

Amyloidosis is a group of diseases in which proteins become amyloid, an insoluble fibrillar aggregate, resulting in organ dysfunction. Amyloid deposition has been reported in various animal species. To diagnose and understand the pathogenesis of amyloidosis, it is important to identify the amyloid precursor protein involved in each disease. Although 42 amyloid precursor proteins have been reported in humans, little is known about amyloidosis in animals, except for a few well-described amyloid proteins, including amyloid A (AA), amyloid light chain (AL), amyloid β (Aβ), and islet amyloid polypeptide-derived amyloid. Recently, several types of novel amyloidosis have been identified in animals using immunohistochemistry and mass spectrometry-based proteomic analysis. Certain species are predisposed to specific types of amyloidosis, suggesting a genetic background for its pathogenesis. Age-related amyloidosis has also emerged due to the increased longevity of captive animals. In addition, experimental studies have shown that some amyloids may be transmissible. Accurate diagnosis and understanding of animal amyloidosis are necessary for appropriate therapeutic intervention and comparative pathological studies. This review provides an updated classification of animal amyloidosis, including associated protein misfolding disorders of the central nervous system, and the current understanding of their pathogenesis. Pathologic features are presented together with state-of-the-art diagnostic methods that can be applied for routine diagnosis and identification of novel amyloid proteins in animals.

Renal alterations in cats (Felis catus) housed in shelters and affected by systemic AA-amyloidosis: Clinicopathological data, histopathology, and ultrastructural features

AA-amyloidosis is frequent in shelter cats, and chronic kidney disease is the foremost cause of death. The aims were to describe kidney laboratory and microscopic findings in shelter cats with AA-amyloidosis. Cats were included if kidney specimens were collected post-mortem and laboratory data were available within 6 months before death. Renal lesions were evaluated with optical and electron microscopy. Mass spectrometry was used to characterize amyloid. Nine domestic short-hair cats were included; 4 females and 5 males with a median age of 8 years (range = 2-13). All cats had blood analyses and urinalyses available. Serum creatinine concentrations were increased in 6 cats and symmetric dimethylarginine was increased in all of the cats. All of the cats had proteinuria. Eight of 9 cats had amyloid in the medulla, and 9 had amyloid in the cortex (glomeruli). All cats had amyloid in the interstitium. Six cats had concurrent interstitial nephritis and 1 had membranoproliferative glomerulonephritis. All cats had extrarenal amyloid deposits. Amyloid was AA in each case. In conclusion, renal deposition of amyloid occurs in both cortex and medulla in shelter cats and is associated with azotemia and proteinuria. Renal involvement of systemic AA-amyloidosis should be considered in shelter cats with chronic kidney disease. The cat represents a natural model of renal AA-amyloidosis.

Assessment of health impacts in retired antisera-producing horses: Blood biochemistry and serum amyloid A analysis

Background and Aim

Horses used for antisera production are repeatedly hyperimmunized to produce high levels of specific antibodies. This prolonged process can lead to various health issues, including amyloidosis, which involves the accumulation of amyloid proteins in organs and tissues, potentially causing organ dysfunction and failure. These horses are often retired when they no longer produce adequate antibody levels. This study aimed to evaluate the impact of prolonged antisera production on the health of retired horses by examining their blood biochemistry and serum amyloid A (SAA) levels, which are indicators of systemic inflammation and organ damage.

Materials and Methods

Blood samples were collected from 12 horses for this study. Nine horses were retired antisera-producing horses that had been discontinued for 2 years, while three healthy non-antisera-producing horses were used as controls. These twelve horses were divided into four groups based on the duration of their active period as antisera producers (never been used, 2-3 years, 4-5 years, and 6-7 years). We measured key blood biochemistry parameters and SAA levels to evaluate the health status of the horses.

Results

Total protein, fibrinogen, and globulin levels were elevated, whereas other parameters remained normal. The findings indicate that despite normal SAA levels, the horses exhibited signs of ongoing health issues related to their previous use in antisera production, such as increased total plasma protein, fibrinogen, and globulin levels, as well as the presence of amyloid deposits in vital organs such as the liver and kidneys, as observed in post-mortem examinations.

Conclusion

Despite normal SAA levels, retired antisera-producing horses showed elevated total protein, fibrinogen, and globulin levels, indicating ongoing health issues.

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.

Renal amyloid-A amyloidosis in cats: Characterization of proteinuria and biomarker discovery, and associations with kidney histology

BACKGROUND

Amyloid A (AA) amyloidosis is a protein misfolding disease arising from serum amyloid A (SAA). Systemic AA amyloidosis recently was shown to have a high prevalence in shelter cats in Italy and was associated with azotemia and proteinuria.

OBJECTIVES

Investigate urine protein profiles and diagnostic biomarkers in cats with renal AA amyloidosis.

ANIMALS

Twenty-nine shelter cats.

METHODS

Case-control study. Cats with renal proteinuria that died or were euthanized between 2018 and 2021 with available necropsy kidney, liver and spleen samples, and with surplus urine collected within 30 days before death, were included. Histology was used to characterize renal damage and amyloid amount and distribution; immunohistochemistry was used to confirm AA amyloidosis. Urine protein-to-creatinine (UPC) and urine amyloid A-to-creatinine (UAAC) ratios were calculated, and sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE) and liquid chromatography-mass spectrometry (LC-MS) of proteins were performed.

RESULTS

Twenty-nine cats were included. Nineteen had AA amyloidosis with renal involvement. Cats with AA amyloidosis had a higher UPC (median, 3.9; range, 0.6-12.7 vs 1.5; 0.6-3.1; P = .03) and UAAC ratios (median, 7.18 × 10-3 ; range, 23 × 10-3 -21.29 × 10-3 vs 1.26 × 10-3 ; 0.21 × 10-3 -6.33 × 10-3 ; P = .04) than unaffected cats. The SDS-AGE identified mixed-type proteinuria in 89.4% of cats with AA amyloidosis and in 55.6% without AA amyloidosis (P = .57). The LC-MS identified 63 potential biomarkers associated with AA amyloidosis (P < .05). Among these, urine apolipoprotein C-III was higher in cats with AA amyloidosis (median, 1.38 × 107 ; range, 1.85 × 105 -5.29 × 107 vs 1.76 × 106 ; 0.0 × 100 -1.38 × 107 ; P = .01). In the kidney, AA-amyloidosis was associated with glomerulosclerosis (P = .02) and interstitial fibrosis (P = .05).

CONCLUSIONS AND CLINICAL IMPORTANCE

Renal AA amyloidosis is associated with kidney lesions, increased proteinuria and increased urine excretion of SAA in shelter cats. Additional studies are needed to characterize the role of lipid transport proteins in the urine of affected cats.

Application of 89Zr-DFO*-immuno-PET to assess improved target engagement of a bispecific anti-amyloid-ß monoclonal antibody

PURPOSE

The recent conditional FDA approval of Aducanumab (Adu) for treating Alzheimer's disease (AD) and the continued discussions around that decision have increased interest in immunotherapy for AD and other brain diseases. Reliable techniques for brain imaging of antibodies may guide decision-making in the future but needs further development. In this study, we used ⁸⁹Zr-immuno-PET to evaluate the targeting and distribution of a bispecific brain-shuttle IgG based on Adu with transferrin receptor protein-1 (TfR1) shuttling mechanism, mAbAdu-scFab8D3, designated Adu-8D3, as a candidate theranostic for AD. We also validated the ⁸⁹Zr-immuno-PET platform as an enabling technology for developing new antibody-based theranostics for brain disorders.

METHODS

Adu, Adu-8D3, and the non-binding control construct B12-8D3 were modified with DFO*-NCS and radiolabeled with ⁸⁹Zr. APP/PS1 mice were injected with ⁸⁹Zr-labeled mAbs and imaged on days 3 and 7 by positron emission tomography (PET). Ex vivo biodistribution was performed on day 7, and ex vivo autoradiography and immunofluorescence staining were done on brain tissue to validate the PET imaging results and target engagement with amyloid-β plaques. Additionally, [⁸⁹Zr]Zr-DFO*-Adu-8D3 was evaluated in 3, 7, and 10-month-old APP/PS1 mice to test its potential in early stage disease.

RESULTS

A 7-fold higher brain uptake was observed for [⁸⁹Zr]Zr-DFO*-Adu-8D3 compared to [⁸⁹Zr]Zr-DFO*-Adu and a 2.7-fold higher uptake compared to [⁸⁹Zr]Zr-DFO*-B12-8D3 on day 7. Autoradiography and immunofluorescence of [⁸⁹Zr]Zr-DFO*-Adu-8D3 showed co-localization with amyloid plaques, which was not the case with the Adu and B12-8D3 conjugates. [⁸⁹Zr]Zr-DFO*-Adu-8D3 was able to detect low plaque load in 3-month-old APP/PS1 mice.

CONCLUSION

⁸⁹Zr-DFO*-immuno-PET revealed high and specific uptake of the bispecific Adu-8D3 in the brain and can be used for the early detection of Aβ plaque pathology. Here, we demonstrate that ⁸⁹Zr-DFO*-immuno-PET can be used to visualize and quantify brain uptake of mAbs and contribute to the evaluation of biological therapeutics for brain diseases.

Identification of novel amyloidosis in dogs: α-S1-casein acquires amyloidogenicity in mammary tumor by overexpression and N-terminal truncation

Mammary tumor-associated amyloidosis (MTAA) in dogs is characterized by amyloid deposition in the stroma of mammary adenoma or carcinoma; however, the amyloid precursor protein remains unknown. We attempted to identify an amyloid precursor protein and elucidated its etiology by characterizing 5 cases of canine MTAA. Proteomic analyses of amyloid extracts from formalin-fixed paraffin-embedded specimens revealed α-S1-casein (CASA1) as a prime candidate and showed the N-terminal truncation of canine CASA1. Both immunohistochemistry and immunoelectron microscopy showed that amyloid deposits or fibrils in MTAA cases were positive for CASA1. Reverse transcription-polymerase chain reaction and quantitative polymerase chain reaction revealed the complete mRNA sequence encoding CASA1, whose expression was significantly higher in the amyloid-positive group. The recombinant protein of the N-terminal-truncated canine CASA1 and the synthetic peptides derived from canine and human CASA1 formed amyloid-like fibrils in vitro. Structural prediction suggested that the N-terminal region of CASA1 was disordered. Previously, full-length CASA1 was reported to inhibit the amyloidogenesis of other proteins; however, we demonstrated that CASA1 acquires amyloidogenicity via excessive synthesis followed by truncation of its disordered N-terminal region. By identifying a novel in vivo amyloidogenic protein in animals and revealing key mechanistic details of its associated pathology, this study provides valuable insights into the integrated understanding of related proteopathies.

AMYLOIDOSIS IN CAPTIVE EUROPEAN EASTERN BONGO (TRAGELAPHUS EURYCERUS ISAACI): PREVALENCE, PREDICTIVE FACTORS, ORGAN PREDILECTION, AND SERUM AMYLOID A CONCENTRATIONS

Amyloidosis is frequently identified during postmortem examination of captive eastern bongo (Tragelaphus eurycerus isaaci) in the European Endangered Species Programme (EEP). However, its significance and etiopathogenesis are poorly understood. The objective of this study was to investigate the prevalence of amyloidosis within this population and identify potential predictive factors for the presence of disease. Postmortem reports obtained from 24 EEP institutions were analyzed and assessed for evidence of amyloidosis. Seventy-two individuals had histopathological assessment performed after gross postmortem examination and were included in the study. Further histopathological analysis was performed on Congo red-stained slides from 26 individuals, and organ predilection sites were identified. Immunohistochemical analysis was performed in six individuals to identify the type of amyloid present. Serum amyloid A (SAA) analysis was performed on blood samples from 34 individuals, and concentrations in affected and unaffected individuals were compared. Amyloidosis was reported in 26 animals (36%). The association between the presence of amyloidosis and sex, age, or body condition was not statistically significant. However, amyloidosis was not identified in any individuals under the age of 6 yr. The presence of chronic inflammatory conditions was the only statistically significant predictive factor for the presence of amyloidosis (P = 0.03). Chronic inflammatory conditions present included nephritis, enteritis, and pneumonia. The majority of affected animals presented with amyloid deposition in multiple organs, with the liver and kidneys being most commonly affected. Immunohistochemistry confirmed the presence of AA amyloid. The association between the presence of amyloidosis and SAA values measured on a single occasion was not statistically significant. This study identified a high prevalence of amyloidosis within the captive European eastern bongo population associated with chronic inflammatory conditions. Antemortem diagnosis of amyloidosis remains challenging, and this study indicates that SAA protein concentrations are not a reliable indicator for the presence of amyloidosis.

Keratinic amyloid deposition in canine hair follicle tumors

Keratinic primary localized cutaneous amyloidosis is a disease in humans; however, no similar condition has been reported in animals. This study aimed to investigate cutaneous keratinic amyloid deposition in dogs and elucidate its etiology. Canine hair follicle tumor tissues were histopathologically analyzed. Immunohistochemistry and mass spectrometry-based proteomic analyses were performed to identify precursor protein candidates. Structural prediction and in vitro fibrillization analyses were conducted to determine the amyloidogenic region and gene sequencing analysis was performed to assess mutations. Of the 266 samples, 16 had amyloid deposition. Amyloid deposits were found in the stroma of tumors and in the margins of keratin debris and around normal hair follicles. Cytokeratin 5 (CK5) was identified as a precursor protein candidate. C-terminal truncation of CK5 was observed in amyloid deposits, and the truncation sites varied depending on the deposition pattern. There was a significantly higher incidence of amyloid deposition in Shiba dogs, and CK5 amino acid polymorphisms were identified in these dogs. A part of the C-terminal region of both canine and human CK5 exhibited highly amyloidogenic properties in vitro. This study revealed the existence of cutaneous keratinic amyloid deposition in animals and identified CK5 as an amyloid precursor protein, providing novel insights into understanding the etiology of cutaneous amyloidosis.

Cryo-EM structure of ex vivo fibrils associated with extreme AA amyloidosis prevalence in a cat shelter

AA amyloidosis is a systemic disease characterized by deposition of misfolded serum amyloid A protein (SAA) into cross-β amyloid in multiple organs in humans and animals. AA amyloidosis occurs at high SAA serum levels during chronic inflammation. Prion-like transmission was reported as possible cause of extreme AA amyloidosis prevalence in captive animals, e.g. 70% in cheetah and 57-73% in domestic short hair (DSH) cats kept in zoos and shelters, respectively. Herein, we present the 3.3 Å cryo-EM structure of AA amyloid extracted post-mortem from the kidney of a DSH cat with renal failure, deceased in a shelter with extreme disease prevalence. The structure reveals a cross-β architecture assembled from two 76-residue long proto-filaments. Despite >70% sequence homology to mouse and human SAA, the cat SAA variant adopts a distinct amyloid fold. Inclusion of an eight-residue insert unique to feline SAA contributes to increased amyloid stability. The presented feline AA amyloid structure is fully compatible with the 99% identical amino acid sequence of amyloid fragments of captive cheetah.

Hepatic Amyloidosis in a Chronically Entangled Grey Seal (Halichoerus grypus)

Grey seal (Halichoerus grypus) entrapment in fishing gear is well documented, consisting of two forms: peracute underwater entrapment and chronic entanglement. We now highlight a previously undescribed sequela to chronic entanglement in a female grey seal estimated to be at least 2 years of age. The animal was first observed in September 2018 on the coast of north Cornwall, southwest England, with a large encircling neck wound consistent with monofilament net entanglement. In April 2021, it was admitted for attempted rehabilitation but had to be euthanized after 9 days due to clinical deterioration despite treatment. At post-mortem examination, the seal was in poor nutritional state, the nose to flipper length was low for its estimated age and the liver was markedly enlarged, pale and friable in texture with evidence of recent and previous hepatic haemorrhage. Histopathology revealed hepatic amyloidosis and evidence of amyloid in one kidney and one adrenal gland. Proteomic analysis of microdissected amyloid from the liver indicated type AA amyloid. Chronic entanglement is the most plausible cause of AA amyloidosis in this animal, indicating that amyloidosis should be considered as a pathological sequela and welfare concern associated with chronic entanglement of grey seals.

Natural Plant Tissue with Bioinspired Nano Amyloid and Hydroxyapatite as Green Scaffolds for Bone Regeneration

Bone defects have been increasingly prevalent around the globe and traditional bone substitutes are constantly limited by low abundance and biosafety due to their animal-based resources. Plant-based scaffolds are currently studied as a green candidate but the bioinertia of cellulose to mammalian cells leads to uncertain bone regeneration. Inspired by the cross-kingdom adhesion of plants and bacteria, this work proposes a concept of a novel plant bone substitute, involving coating decellularized plant with nano amyloids and nano hydroxyapatites, to bridge the plant scaffold and animal tissue regeneration. Natural microporosity of plants can guide alignment of mammalian cells into various organ-like structures. Taking advantage of the bioactive nano amyloids, the scaffolds drastically promote cell adhesion, viability, and proliferation. The enhanced bio-affinity is elucidated as positively charged nano amyloids and serum deposition on the nanostructure. Nano-hydroxyapatite crystals deposited on amyloid further prompt osteogenic differentiation of pre-osteoblasts. In vivo experiments prove successful trabeculae regeneration in the scaffold. Such a hierarchical design leverages the dedicated microstructure of natural plants and high bioactivity of nano amyloid/hydroxyapatite coatings, and addresses the abundant resource of bone substitutes. Not limited to their current application, plant materials functionalized with nano amyloid/hydroxyapatite coatings allow many cross-kingdom tissue engineering and biomedical applications.

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Non-proliferative and Proliferative Lesions of the Non-human Primate (M. fascicularis)

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in most tissues and organs from the nonhuman primate used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.

Survey of amyloidosis cases among different free-living wild and zoo animals

Amyloidosis comprises a range of protein-folding disorders characterised by a buildup of amyloid deposits in one or multiple organs. The pathogenesis and pathologic findings of amyloidosis can vary widely due to the nature of the precursor protein. In veterinary medicine, there are 10 proteins known to form amyloid deposits in various organs. This review aims to compare amyloidosis cases among different free-living wild and zoo animals focussing in part on the determination of the species particularly susceptible to the amyloid formation and specific prone-to-aggregate protein commonly involved. This review addresses the transmission of AA amyloidosis pertinent to institutions, such as zoos, housing multiple individuals and species in relatively close proximity. In addition, this review includes summarisation for definitive diagnosis of single or multiple cases of amyloidosis affecting free-living wild and zoo animals. Insights into the diversity, transmission, and pathogenesis of known amyloidogenic proteins and species prevalently affected may help to establish a preventive intervention and stimulate the discovery of new diagnostic and therapeutic strategies.

Actinomycosis in a gray four-eyed opossum (Philander opossum) caused by a novel species of Schaalia

BACKGROUND

Infective lesions of the jaws and adjacent tissues (lumpy jaw disease, LJD) have been recognized as one major cause of death of captive macropods. Fusobacterium necrophorum and Actinomyces species serve as the main source of LJD in kangaroos and wallabies. Currently, little is reported about LJD or similar diseases in opossums.

CASE PRESENTATION

Here we report a case of actinomycosis resembling the entity lumpy jaw disease in a gray four-eyed opossum, caused by a novel species of Schaalia. A 2.8 year old male Philander opossum was presented with unilateral swelling of the right mandible. After an initial treatment with marbofloxacin, the opossum was found dead the following day and the carcass was submitted for necropsy. Postmortem examination revealed severe mandibular skin and underlying soft tissue infection with subsequent septicemia as the cause of death. Histological examination demonstrated Splendore-Hoeppli phenomenon, typically seen in classical cases of actinomycosis. Bacteriology of liver and mandibular mass yielded a previously undescribed species of Schaalia, whose 16 S rRNA gene sequence was 97.0 % identical to Schaalia canis. Whole genome sequencing of the opossum isolate and calculation of average nucleotide identity confirmed a novel species of Schaalia, for which no whole genome sequence is yet available.

CONCLUSIONS

The herewith reported Schaalia infection in the gray four-eyed opossum resembling classical actinomycosis gives a novel insight into new exotic animal bacterial diseases. Schaalia species may belong to the normal oral microbiome, as in macropods, and may serve as a contributor to opportunistic infections. Due to the lack of current literature, more insights and improved knowledge about Schaalia spp. and their pathogenicity will be useful to choose appropriate therapy regimens and improve the treatment success rate and outcome in exotic and endangered species.

Bullous amyloidosis in a horse: first description in veterinary medicine

BACKGROUND

Bullous amyloidosis is a rare disease in humans that has not been described in a veterinary species in the peer-reviewed literature. The human disease is characterised by haemorrhagic vesicles and bullae on the skin and mucosae, which form due to amyloid deposition.

HYPOTHESIS/OBJECTIVES

To describe the clinical features, laboratory analysis and histopathological features of an unique presentation of bullous disease in a horse.

ANIMALS

A 17-year-old thoroughbred mare presented for weight loss and severe oral cavity ulcers.

METHODS AND MATERIALS

Investigations involved haematological evaluation, chemistry profiles, gastroscopy and serum protein electrophoresis, and, postmortem, histopathological evaluation, Congo-red staining and transmission electron microscopy (TEM).

RESULTS

Haemorrhagic vesicles and bullae occurred on the mucosa of the oral cavity, lips, oesophagus and stomach, and much less the muzzle, face and mucocutaneous areas of the perineum, where scarring was evident. Histopathological evaluation and Congo-red staining confirmed the presence of amyloid deposits in dermis and submucosa, in association with vesicle and bulla formation, consistent with bullous amyloidosis. TEM confirmed amyloid fibril deposition in the dermis and along the basement membrane zone. Clefts occurred in the superficial dermis and submucosa, which explained haemorrhage and scarring. The presence of a polyclonal gammopathy and the rapid abolishment of Congo-red staining with performate pretreatment supported serum amyloid A and secondary amyloidosis.

CONCLUSION AND CLINICAL IMPORTANCE

Bullous amyloidosis is a novel disease of the horse and a newly recognised differential for bullous disease, for which the haemorrhagic nature of bullae, scarring and deep secondary ulcers are considered clinical clues to the condition.

AMYLOIDOSIS IN CARACALS (CARACAL CARACAL)

Nine cases of amyloidosis in caracals (Caracal caracal) from three different institutions in Europe were reviewed and evaluated histopathologically. The six males and three females died between 2008 and 2018 at an age of 6 yr ± 2.5 mo (median ± interquartile range). In two out of nine (2/9) animals, amyloidosis was an incidental postmortem finding; the animals died of bronchopneumonia and gastric ulceration due to Helicobacter spp., respectively. Seven (7/9) animals suffered from acute renal failure due to amyloidosis, one of them additionally of cardiac decompensation. The predominant clinical signs were weight loss, lethargy, dys- or anorexia, dehydration, increased BUN and creatinine, and azotemia. The main gross lesion was a pale renal cortex on cut surface; in two animals, the kidneys appeared enlarged. Histologically, glomerular amyloid was present in every animal (9/9), and was the predominant renal manifestation of amyloidosis. Additional findings included splenic amyloid (8/8), amyloid in the lamina propria of the intestine (5/5), and amyloid in the lingual submucosa (4/4). Gastric mineralization was present in four animals suffering from renal failure. In the animal dying from bronchopneumonia, severe pancreatic amyloid deposits mainly affecting the exocrine pancreas (1/5) were identified. Immunohistochemistry was employed to identify amyloid AA in eight cases; only in the caracal dying from bronchopneumonia AA was amyloid confirmed. In several organs, especially in those where only small amyloid deposits were detected, a Congo red stain was often necessary to confirm the deposition. The etiology of the amyloidosis remains unknown. Three caracals were related within two generations, another three within four generations, so one might hypothesize a familial trait. In conclusion, amyloidosis should be considered as a significant disease in the caracal. Particularly in cases with renal disease, it should be included as a major differential diagnosis.

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.

Pathology and Proteomics-Based Diagnosis of Localized Light-Chain Amyloidosis in Dogs and Cats

Amyloidosis is classified according to the amyloid precursor protein, and accurate diagnosis of the amyloidosis type may guide appropriate treatment. Immunohistochemistry and Congo red staining are the most frequently used methods used to distinguish types of amyloidosis, but problems with specificity and sensitivity indicate the need for an alternative diagnostic method. In this study, we evaluated laser microdissection-liquid chromatography-tandem mass spectrometry (LMD-LC-MS/MS) for the diagnosis of amyloid light-chain (AL) amyloidosis in animals. Plasmacytomas with amyloid deposits from 15 dogs and 2 cats were subjected to Congo red staining with or without potassium permanganate pretreatment, immunohistochemistry for kappa and lambda light chains, and LMD-LC-MS/MS. Congo red staining was diagnostic in 12 of 17 cases based on resistance to potassium permanganate pretreatment, but in 5 of 17 cases the pretreatment unexpectedly reduced Congo red staining or abrogated the birefringence and a definitive diagnosis could not be reached. Immunohistochemistry detected kappa or lambda light chains in 6 of 17 cases. With LMD-LC-MS/MS, immunoglobulin lambda light chain was detected in all 17 cases. The amyloid signature proteins ApoA-I, ApoA-IV, and ApoE were detected in 9, 1, and 3 of the 15 canine cases by LMD-LC-MS/MS, but not in the feline cases. In conclusion, LMD-LC-MS/MS consistently determined the amyloid type in all examined specimens, while Congo red staining after potassium permanganate treatment and immunohistochemistry were less sensitive tests.

Interplay between Oxidative Stress, Inflammation, and Amyloidosis in the Anterior Segment of the Eye; Its Pathological Implications

There are different pathologies associated with amyloidogenic processes caused by the increase of reactive oxygen species (ROS) and the overactivation of inflammatory responses. These alterations are present in different regions of the anterior segment of the eye, and they have been associated with the development and progression of ocular pathologies, such as glaucoma, dry eye syndrome, keratitis, and cataracts among other pathologies. Aim. To discuss briefly the anatomical characteristics of the anterior segment of the eye and describe the interaction between oxidative stress (OS) and inflammatory responses, emphasizing the misfolding of several proteins leading to amyloidogenic processes occurring in the anterior segment and their implications in the development of ocular diseases. We performed a search on PubMed, CINAHL, and Embase using the MeSH terms “eye,” “anterior segment”, “inflammation”, “oxidative stress”, and “amyloidosis”. The search encompassed manuscripts published up to April 2019. A hundred forty-four published studies met the inclusion criteria. We present the current knowledge regarding the interaction between OS and the activation of inflammatory processes and how both can cause conformational changes in several peptides and proteins in each compartment of the anterior segment. However, we found that there is no consensus about which factor is the first to cause amyloidosis. Our conclusions suggest that there is an interplay among these factors forming a vicious cycle that leads to the loss of protein structure in ocular pathologies, and multifactorial therapies should be developed to avoid protein misfolding and to stop the progression of ocular pathologies.

Retrospective analysis of complications associated with retrobulbar bupivacaine in dogs undergoing enucleation surgery

OBJECTIVE

To investigate complications associated with, and without, bupivacaine retrobulbar local anesthesia in dogs undergoing unilateral enucleation surgery.

STUDY DESIGN

Retrospective, observational study.

ANIMALS

A total of 167 dogs underwent unilateral enucleation surgery via a transpalpebral approach.

METHODS

Records from 167 dogs that underwent unilateral enucleation surgery that did (RB) or did not (NB) include retrobulbar bupivacaine anesthesia were reviewed, including anesthetic record, daily physical examination records, surgery report, patient discharge report and patient notes within 14 days of the surgery. Specific complications and severity were compared between RB and NB using the Wilcoxon rank-sum test. A 'complication burden' (0-5) comprising five prespecified complications was assigned and tested using rank-sum procedures. Statistical significance was set to 0.05.

RESULTS

Group RB included 97 dogs and group NB 70 dogs. Dogs in NB had a 17.0 percentage points (points) greater risk for a postoperative recovery complication (38.6% versus 21.6%; 95% confidence interval: 3.0-30.6 points; p = 0.017). There was inconclusive evidence that dogs in group RB had a lower risk of requiring perioperative anticholinergic administration (12.4% versus 22.9%; 10.5 points; p = 0.073). Other complications were similar between groups RB and NB with risks that differed by <10 points. The risk of hemorrhage was similar between groups RB (22.7%) and NB (20.0%) with no significant difference in the level of severity (p = 0.664).

CONCLUSIONS AND CLINICAL RELEVANCE

In this retrospective study, the use of retrobulbar bupivacaine for enucleation surgery in dogs was not associated with an increased risk of major or minor complications.

Feline abdominal ultrasonography: what's normal? what's abnormal? The kidneys and perinephric space

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the kidneys and perinephric space can provide important information on several conditions including chronic renal disease, hydronephrosis and perinephric pseudocyst formation.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even for the experienced ultrasonographer, differentiating between incidental findings, such as a medullary rim sign, and pathological changes can be challenging.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses ultrasonographic examination of the normal and diseased kidney and perinephric space. Aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material. A subsequent article will address ultrasonography of the collecting system including the renal pelvis and urinary bladder.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Allelic Diversity in the Serum Amyloid A2 Gene and Amyloid A Amyloidosis in a Breeding Colony of Zebra Finches (Taeniopygia guttata)

A high incidence of amyloid A (AA) amyloidosis was observed in the research breeding colony of zebra finches at our institution. Some birds with hepatic AA amyloidosis were asymptomatic for comorbid conditions frequently associated with the development of AA amyloidosis, whereas other birds with comorbid conditions failed to develop AA amyloidosis, suggesting a potential genetic component to the disease. Sequencing the SAA2 gene from 20 birds yielded 18 distinct sequences that coded for 5 isoforms of the protein. Most of the amino acid substitutions are unlikely to affect the protein's structure or function, but 2 changes-R52L and V84M-were predicted to be disruptive. In particular, R52 is highly conserved across vertebrates, with only arginine or lysine found at this position in reported sequences to date. The atypical R52L substitution occurred in 2 otherwise healthy birds with hepatic AA amyloidosis, supporting the idea that this change is pathogenic.

Amyloidosis and Longevity: A Lesson from Plants

The variety of lifespans of different organisms in nature is amazing. Although it is acknowledged that the longevity is determined by a complex interaction between hereditary and environmental factors, many questions about factors defining lifespan remain open. One of them concerns a wide range of lifespans of different organisms. The reason for the longevity of certain trees, which reaches a thousand years and exceeds the lifespan of most long living vertebrates by a huge margin is also not completely understood. Here we have discussed some distinguishing characteristics of plants, which may explain their remarkable longevity. Among them are the absence (or very low abundance) of intracellular inclusions composed of amyloidogenic proteins, the lack of certain groups of proteins prone to aggregate and form amyloids in animals, and the high level of compounds which inhibit protein aggregation and possess antiaging properties.

Amyloid A amyloidosis secondary to avian tuberculosis in naturally infected domestic pekin ducks (Anas platyrhynchos domestica)

To investigate the correlation between avian tuberculosis and duck amyloidosis, the liver, lung, spleen, kidney, duodenum and pectoralis muscle of ducks naturally infected with Mycobacterium avium subsp. avium were used to detect amyloidosis by Congo red staining and potassium permanganate-Congo red staining. The expression level of IL-1β, IL-6, IL-10, TNF-α and SAA2 were detected by quantitative real-time RT-PCR (qRT-PCR). The results showed that the liver, lung, spleen, kidney, duodenum and pectoralis muscle of the infected ducks exhibited amyloid proteins under ordinary light microscopy and the polarization light under polarized light microscopy. However, no amyloid deposition in potassium permanganate-Congo red staining sections indicated that the amyloidosis was AA amyloidosis. In addition, the expression level of IL-1β, IL-6, IL-10, TNF-α and SAA2 increased from 4 to 43. This study showed that avian tuberculosis could induce secondary amyloidosis in naturally infected ducks.

Fatal pulmonary hemorrhage associated with vascular amyloid deposition in a cat

Case summary

An adult female spayed Siamese-cross cat of unknown age was presented for bilateral hemorrhagic otorrhea. Nasopharyngeal polyps were diagnosed by CT and biopsy; bilateral ventral bulla osteotomies were performed. Episodic epistaxis, otic hemorrhage and hemoptysis with respiratory distress progressed over 18 months. Systolic blood pressure, complete blood count, plasma biochemistries, prothrombin time, partial thromboplastin time and coagulation factor 12, 9 and 8 activities were normal. Serial thoracic radiographs revealed patchy interstitial to alveolar patterns. Airway hemorrhage prevented diagnostic bronchoscopy. Respiratory hemorrhage was ultimately fatal. Amyloid deposition was identified in pulmonary vasculature, bronchial wall, lymphoid tissues, nasal-pharyngeal tissue and tympanic bullae based on microscopic examination and confirmed by Congo red staining with green birefringence under polarized light.

Relevance and novel information

Amyloidosis should be considered as a differential diagnosis in cats with spontaneous hemorrhage of the respiratory or otic tracts. Although systemic amyloidosis is associated with a grave prognosis, this case suggests that prolonged survival is possible after the initial onset of signs in cats with pulmonary amyloidosis.

Mortalities, amyloidosis and other diseases in free-living red squirrels (Sciurus vulgaris) on Jersey, Channel Islands

Between 2007 and 2014, 337 free-living red squirrels (Sciurus vulgaris) on Jersey, Channel Islands, were examined post mortem as part of a mortality and disease surveillance scheme. Road traffic accidents (RTAs) were attributable for 50.7 per cent (171/337) of the casualties, 34.4 per cent (116/337) succumbed to diseases including fatal exudative dermatitis (FED), 7.1 per cent (24/337) to predation, 6.5 per cent (22/337) to other trauma and 1.2 per cent (4/337) to suspected poisoning. Cat predation accounted for 5 per cent (17/337) of mortalities. Pathologies were diverse and individual animals were often identified with more than one disease process. Squirrelpox virus (SQPV) particles were not detected in selected cases examined by transmission electron microscopy (TEM). Amyloid was identified in 19.3 per cent (65/337) of squirrels, often in conjunction with inflammatory lesions like hepatic capillariasis. A consistent cause of amyloid accumulation was not identified, although there was a significant association of amyloidosis with hepatic capillariasis and FED. In addition to RTAs, amyloidosis and FED have been identified as important causes of squirrel morbidity and mortality on Jersey, while the underlying aetiology and predisposing factors for these two disease complexes are presently unclear. Disease, fragmented woodlands, an increasingly suburban habitat, along with various anthropogenic factors, may jeopardise the long-term viability of this island red squirrel population.

Accelerated pre-senile systemic amyloidosis in PACAP knockout mice - a protective role of PACAP in age-related degenerative processes

Dysregulation of neuropeptides may play an important role in aging‐induced impairments. Among them, pituitary adenylate cyclase‐activating polypeptide (PACAP) is a potent cytoprotective peptide that provides an endogenous control against a variety of tissue‐damaging stimuli. We hypothesized that the progressive decline of PACAP throughout life and the well‐known general cytoprotective effects of PACAP lead to age‐related pathophysiological changes in PACAP deficiency, supported by the increased vulnerability to various stressors of animals partially or totally lacking PACAP. Using young and aging CD1 PACAP knockout (KO) and wild type (WT) mice, we demonstrated pre‐senile amyloidosis in young PACAP KO animals and showed that senile amyloidosis appeared accelerated, more generalized, more severe, and affected more individuals. Histopathology showed age‐related systemic amyloidosis with mainly kidney, spleen, liver, skin, thyroid, intestinal, tracheal, and esophageal involvement. Mass spectrometry‐based proteomic analysis, reconfirmed with immunohistochemistry, revealed that apolipoprotein‐AIV was the main amyloid protein in the deposits together with several accompanying proteins. Although the local amyloidogenic protein expression was disturbed in KO animals, no difference was found in laboratory lipid parameters, suggesting a complex pathway leading to increased age‐related degeneration with amyloid deposits in the absence of PACAP. In spite of no marked inflammatory histological changes or blood test parameters, we detected a disturbed cytokine profile that possibly creates a pro‐inflammatory milieu favoring amyloid deposition. In summary, here we describe accelerated systemic senile amyloidosis in PACAP gene‐deficient mice, which might indicate an early aging phenomenon in this mouse strain. Thus, PACAP KO mice could serve as a model of accelerated aging with human relevance. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Causes of mortality and morbidity in free-ranging mustelids in Switzerland: necropsy data from over 50 years of general health surveillance

BACKGROUND

Although mustelids occur worldwide and include a wide range of species, little is known about the diseases affecting them. Mustelids have regularly been submitted for post mortem investigation in the framework of the program for general wildlife health surveillance in Switzerland, which has been in place for nearly 60 years. We performed a retrospective analysis of the necropsy reports on mustelids submitted to the diagnostic service of the University of Bern. The aims of this study were to present an overview of the causes of mortality and morbidity observed in these carnivores, to assess differences among species, to assess changes in disease detection over the study period, and to describe the pathology of selected diseases.

RESULTS

Five hundred and sixty-six reports from 1958 to 2015 were analyzed. Most animals were stone martens (Martes foina, 46%) and badgers (Meles meles, 44%); the remaining species were polecats (Mustela putorius, 4.7%), pine martens (Martes martes, 2%), stoats (Mustela erminea, 1.4%), weasels (Mustela nivalis, 0.8%) and otters (Lutra lutra, 0.3%). Infectious diseases (n = 262) were frequent and were mostly bacterial or viral; non-infectious conditions (n = 169) were less common and were mostly traumatic or due to metabolic disorders. The most frequent diagnoses included distemper (75% were badgers), amyloidosis (96% were martens), bacterial respiratory infections (all mustelids), biting lice (badgers only) and pulmonary and gastro-intestinal helminths (all species). Less frequent diseases included histoplasmosis (badgers only), aspergillosis, toxoplasmosis, hepatozoonosis, and sarcoptic mange. Lesions due to infection with distemper virus were primarily appreciated in the respiratory tract and central nervous system; they presented species-specific characteristics such as necrosis in the ependyma in badgers and absence of syncytia in stone martens. Amyloidosis in martens was multisystemic in most cases and included both AA and AL amyloidosis; the main macroscopic change was severe splenomegaly.

CONCLUSION

Infectious diseases were the most frequent causes of morbidity and mortality of mustelids, with marked species-specific differences. Lung and skin were the most commonly affected organs. Contagious diseases such as canine distemper, sarcoptic mange and rabies in mustelids showed a similar temporal pattern as in red foxes (Vulpes vulpes), suggesting pathogen spillovers from foxes to mustelids.

Comparative occurrence of diabetes in canine, feline, and few wild animals and their association with pancreatic diseases and ketoacidosis with therapeutic approach

Diabetes mellitus (DM) is a chronic metabolic disorder in which blood glucose level raises that can result in severe complications. However, the incidence increased mostly by obesity, pregnancy, persistent corpus luteum, and diestrus phase in humans and animals. This review has focused on addressing the possible understanding and pathogenesis of spontaneous DM in canine, feline, and few wild animals. Furthermore, pancreatic associated disorders, diabetic ketoacidosis, hormonal and drug interaction with diabetes, and herbal remedies associated with DM are elucidated. Bibliographic search for the present review was done using PubMed, Scopus, and Google Scholar for articles on concurrent DM in small and wild animals. Persistent corpus luteal and pseudopregnancy in female dogs generate gestational DM (GDM). GDM can also be caused by extensive use of drugs/hormones such as glucocorticosteroids. Although many similarities are present between diabetic cats and diabetic humans which present islet amyloidosis, there was a progressive loss of β- and α-cells and the normal number of δ-cells. The most prominent similarity is the occurrence of islet amyloidosis in all cases of diabetic cat and over 90% of human non-insulin dependent DM Type-2. Acute pancreatic necrosis (APN) occurs due to predisposing factors such as insulin antagonism, insulin resistance, alteration in glucose tolerance, obesity, hyperadrenocorticism, and persistent usage of glucocorticoids, as these play a vital role in the progression of APN. To manage such conditions, it is important to deal with the etiological agent, risk factors, diagnosis of diabetes, and hormonal and drug interaction along with its termination with suitable therapy (herbal) protocols. It should be noted that the protocols used for the diagnosis and treatment of human DM are not appropriate for animals. Further investigations regarding diabetic conditions of pets and wild animals are required, which will benefit the health status of all animals health worldwide.

R202Q/M694V as novel MEFV gene mutations in chronic periodontitis and familial Mediterranean fever

BACKGROUND AND OBJECTIVE

Familial Mediterranean fever (FMF) and chronic periodontitis are inflammatory diseases leading to an increase in the number of inflammasomes. To date, no published studies have reported on mutations in the Mediterranean fever (MEFV) gene in patients with chronic periodontitis, although the roles of MEFV gene mutations in FMF and FMF-associated amyloidosis (FMF-A) are well known. Therefore, the aim of this study was to evaluate the frequencies of MEFV gene mutations and serum amyloid A (SAA) and high-sensitivity C-reactive protein (hs-CRP) levels in patients with chronic periodontitis, FMF and FMF-A.

MATERIAL AND METHODS

The study population included 122 patients with FMF and 128 subjects who were systemically healthy. Clinical periodontal parameters, including the plaque index, gingival index, probing pocket depth, clinical attachment level and percentage of bleeding on probing were recorded. Blood samples were obtained from patients with FMF and systemically healthy controls, and all mutations located on exons 2 and 10 of the MEFV gene were analyzed by DNA Sanger Sequencing, which is the gold standard. SAA and high-sensitive CRP levels were also assessed.

RESULTS

Mean gingival index, percentage of bleeding on probing, probing pocket depth and clinical attachment level, and the levels of SAA and hs-CRP were higher in the FMF-A group than those in the FMF and control groups. The two most relevant mutations in patients with FMF were heterozygous M694V (46.2%), and heterozygous R202Q (32.7%). The frequencies of the homozygous M694V and R202Q mutations in the FMF-A group were 53.8% and 46.1%, respectively. The complex R202Q/M694V homozygous state led to an increased risk of chronic periodontitis (odds ratio: 3.6), and FMF-A (odds ratio: 7.6).

CONCLUSION

This is the first study to report the R202Q mutation in patients with periodontitis. Furthermore, the MEFV gene-mediated inflammatory pathway increased serum acute phase reactants, and the changes in the R202Q and M694V could play a role in inflammatory-genetic diseases, such as FMF, FMF-associated amyloidosis and chronic periodontitis.

Amyloidosis in a Captive Zebra Finch (Taeniopygia guttata) Research Colony

Five birds in a captive zebra finch research colony were diagnosed with systemic amyloidosis within a 7-mo period by means of postmortem Congo red staining and green birefringence under polarized light. The liver was the most frequently and usually the most seriously affected organ, followed by the spleen and then the kidney. All 5 birds had been clinically affected with various inflammatory, infectious, and neoplastic conditions associated with amyloid A (AA) amyloidosis in humans and animals. Immunohistochemistry using antisera against duck AA protein revealed that tissues from 2 of the 5 birds were positive for the presence of AA protein and systemic inflammation-associated amyloidosis. Although the development of AA amyloidosis has been associated with chronic inflammation, trauma, and various infectious and neoplastic diseases as well as possible genetic predispositions and stresses linked to overcrowding, the root causes for individual cases of AA amyloidosis are incompletely understood. As far as we know, this report is the first description of AA amyloidosis in captive, research zebra finches.

Amyloid associated with neoplasia in two captive tricolour sharkminnows Balantiocheilus melanopterus Bleeker

Amyloid associated with pancreatic adenocarcinoma was discovered in two captive adult tricolour sharkminnows Balantiocheilus melanopterus Bleeker found dead in a freshwater display. Enlarged abdomens expanded by bloody ascitic fluid and grossly visible masses of abnormal tissue were present surrounding sections of the stomach and intestine. Histologically, the masses were composed of areas of well-organized exocrine pancreatic acini interspersed with cords of poorly differentiated, spindle-shaped cells that compressed and effaced normal parenchyma. These cells possessed small numbers of cytoplasmic zymogen granules; the exocrine nature of these cells was confirmed using transmission electron microscopy (TEM). Fibrovascular connective tissue of the hepatopancreas and mesenteries was expanded by lightly eosinophilic, hyaline, homogeneous acellular material. Similar material greatly expanded the tunica media of large blood vessels in the hepatopancreas. After staining with Congo red or thioflavin T, this material exhibited red-green dichroism under polarized light or bright green fluorescence under ultraviolet light (255 nm), respectively. The non-branching fibrils, of indeterminate length, had an approximate diameter of 10-20 nm using TEM. Although exocrine pancreatic neoplasia is relatively common in fish, the presence of amyloid is not. To our current knowledge, the latter has not yet been described in association with a neoplastic lesion in fish.

Long-term kinetics of AA amyloidosis and effects of inflammatory restimulation after disappearance of amyloid depositions in mice

Amyloid A (AA) amyloidosis is characterized by extracellular pathogenic deposition of insoluble fibril protein in various body organs. Deposited amyloid generally remains in a variety of organs for long periods, but its disappearance has been reported after the precursor protein is diminished. The kinetics of AA deposition are not completely understood and, in particular, the roles of cells and cytokines in the deposition and clearance of amyloid remain unclear. In this study, we investigated the disappearance of amyloid depositions in mice over a 1-year period. AA amyloidosis was induced experimentally in mice by injecting amyloid-enhancing factor (AEF) and silver nitrate. Mice were killed at different time-points to examine the occurrence and disappearance of amyloid depositions. Maximum levels of amyloid depositions were observed at 20 days after inoculation. Clearance of amyloid depositions was observed from the 40th day onwards, with only minute traces of amyloid present by 240 days. A second inflammatory stimulus consisting of AEF and silver nitrate was given at 330 or 430 days, after amyloid depositions had disappeared almost completely. After that, serum amyloid A was overproduced and redeposition of amyloid was observed, indicating that all mice were primed for aggressive amyloid depositions. After administration of the inflammatory stimuli, the proinflammatory environment was found to have increased levels of interleukin (IL)-6, while anti-inflammatory conditions were established by IL-10 as regression of amyloid deposition occurred. These results suggest that the proinflammatory and anti-inflammatory status have key roles in both amyloid deposition and clearance.

Intrinsic Stability, Oligomerization, and Amyloidogenicity of HDL-Free Serum Amyloid A

Serum amyloid A (SAA) is an acute-phase reactant protein predominantly bound to high-density lipoprotein in serum and presumed to play various biological and pathological roles. Upon tissue trauma or infection, hepatic expression of SAA increases up to 1,000 times the basal levels. Prolonged increased levels of SAA may lead to amyloid A (AA) amyloidosis, a usually fatal systemic disease in which the amyloid deposits are mostly comprised of the N-terminal 1-76 fragment of SAA. SAA isoforms may differ across species in their ability to cause AA amyloidosis, and the mechanism of pathogenicity remains poorly understood. In vitro studies have shown that SAA is a marginally stable protein that folds into various oligomeric species at 4 °C. However, SAA is largely disordered at 37 °C, reminiscent of intrinsically disordered proteins. Non-pathogenic murine (m)SAA2.2 spontaneously forms amyloid fibrils in vitro at 37 °C whereas pathogenic mSAA1.1 has a long lag (nucleation) phase, and eventually forms fibrils of different morphology than mSAA2.2. Remarkably, human SAA1.1 does not form mature fibrils in vitro. Thus, it appears that the intrinsic amyloidogenicity of SAA is not a key determinant of pathogenicity, and that other factors, including fibrillation kinetics, ligand binding effects, fibril stability, nucleation efficiency, and SAA degradation may play key roles. This chapter will focus on the known structural and biophysical properties of SAA and discuss how these properties may help better understand the molecular mechanism of AA amyloidosis.

Prion and prion-like diseases in animals

Transmissible spongiform encephalopaties (TSEs) are fatal neurodegenerative diseases characterized by the aggregation and accumulation of the misfolded prion protein in the brain. Other proteins such as β-amyloid, tau or Serum Amyloid-A (SAA) seem to share with prions some aspects of their pathogenic mechanism; causing a variety of so called prion-like diseases in humans and/or animals such as Alzheimer's, Parkinson's, Huntington's, Type II diabetes mellitus or amyloidosis. The question remains whether these misfolding proteins have the ability to self-propagate and transmit in a similar manner to prions. In this review, we describe the prion and prion-like diseases affecting animals as well as the recent findings suggesting the prion-like transmissibility of certain non-prion proteins.

Diagnosis of amyloidosis and differentiation from chronic, idiopathic enterocolitis in rhesus (Macaca mulatta) and pig-tailed (M. nemestrina) macaques

Amyloidosis is a progressive and ultimately fatal disease in which amyloid, an insoluble fibrillar protein, is deposited inappropriately in multiple organs, eventually leading to organ dysfunction. Although this condition commonly affects macaques, there is currently no reliable method of early diagnosis. Changes in clinical pathology parameters have been associated with amyloidosis but occur in late stages of disease, are nonspecific, and resemble those seen in chronic, idiopathic enterocolitis. A review of animal records revealed that amyloidosis was almost always diagnosed postmortem, with prevalences of 15% and 25% in our rhesus and pig-tailed macaque colonies, respectively. As a noninvasive, high-throughput diagnostic approach to improve antemortem diagnosis of amyloidosis in macaques, we evaluated serum amyloid A (SAA), an acute-phase protein and the precursor to amyloid. Using necropsy records and ELISA analysis of banked serum, we found that SAA is significantly elevated in both rhesus and pig-tailed macaques with amyloid compared with those with chronic enterocolitis and healthy controls. At necropsy, 92% of rhesus and 83% of pig-tailed had amyloid deposition in either the intestines or liver. Minimally invasive biopsy techniques including endoscopy of the small intestine, mucosal biopsy of the colon, and ultrasound-guided trucut biopsy of the liver were used to differentiate macaques in our colonies with similar clinical presentations as either having amyloidosis or chronic, idiopathic enterocolitis. Our data suggest that SAA can serve as an effective noninvasive screening tool for amyloidosis and that minimally invasive biopsies can be used to confirm this diagnosis.

Reactive amyloidosis associated with ischial callosititis: a report with histology of ischial callosities in rhesus macaques (Macaca mulatta)

Ischial callosities have received little attention in veterinary medicine even though they are distinguishing anatomic organs. The organs are characterized by a pair of hairless pads of thickened epidermis, located bilaterally in the gluteal region, which overlay the tuberosities of the ischia of all Old World monkeys, gibbons, and siamangs. The current report describes a case of reactive amyloidosis associated with ischial callosititis in a rhesus macaque (Macaca mulatta). Amyloid A (AA) protein was found in the liver, spleen, small intestine, mesenteric lymph nodes, and ischial callosities by histology, Congo red stain, and immunohistochemistry. Confocal microscopy showed that many cluster of differentiation (CD)68-positive macrophages within the ischial callosities contained intracellular AA protein, which suggests that CD68-positive macrophages have an important role in the pathogenesis of reactive amyloidosis in nonhuman primates. The normal histology of ischial callosities of rhesus macaques is also documented in this report.