Multi-omic analyses in Abyssinian cats with primary renal amyloid deposits.

The amyloidoses constitute a group of diseases occurring in humans and animals that are characterized by abnormal deposits of aggregated proteins in organs, affecting their structure and function. In the Abyssinian cat breed, a familial form of renal amyloidosis has been described. In this study, multi-omics analyses were applied and integrated to explore some aspects of the unknown pathogenetic processes in cats. Whole-genome sequences of two affected Abyssinians and 195 controls of other breeds (part of the 99 Lives initiative) were screened to prioritize potential disease-associated variants. Proteome and miRNAome from formalin-fixed paraffin-embedded kidney specimens of fully necropsied Abyssinian cats, three affected and three non-amyloidosis-affected were characterized. While the trigger of the disorder remains unclear, overall, (i) 35,960 genomic variants were detected; (ii) 215 and 56 proteins were identified as exclusive or overexpressed in the affected and control kidneys, respectively; (iii) 60 miRNAs were differentially expressed, 20 of which are newly described. With omics data integration, the general conclusions are: (i) the familial amyloid renal form in Abyssinians is not a simple monogenic trait; (ii) amyloid deposition is not triggered by mutated amyloidogenic proteins but is a mix of proteins codified by wild-type genes; (iii) the form is biochemically classifiable as AA amyloidosis.

Circulating tumor DNA is detectable in canine histiocytic sarcoma, oral malignant melanoma, and multicentric lymphoma.

Circulating tumor DNA (ctDNA) has become an attractive biomarker in human oncology, and its use may be informative in canine cancer. Thus, we used droplet digital PCR or PCR for antigen receptor rearrangement, to explore tumor-specific point mutations, copy number alterations, and chromosomal rearrangements in the plasma of cancer-affected dogs. We detected ctDNA in 21/23 (91.3%) of histiocytic sarcoma (HS), 2/8 (25%) of oral melanoma, and 12/13 (92.3%) of lymphoma cases. The utility of ctDNA in diagnosing HS was explored in 133 dogs, including 49 with HS, and the screening of recurrent PTPN11 mutations in plasma had a specificity of 98.8% and a sensitivity between 42.8 and 77% according to the clinical presentation of HS. Sensitivity was greater in visceral forms and especially related to pulmonary location. Follow-up of four dogs by targeting lymphoma-specific antigen receptor rearrangement in plasma showed that minimal residual disease detection was concordant with clinical evaluation and treatment response. Thus, our study shows that ctDNA is detectable in the plasma of cancer-affected dogs and is a promising biomarker for diagnosis and clinical follow-up. ctDNA detection appears to be useful in comparative oncology research due to growing interest in the study of natural canine tumors and exploration of new therapies.

Atypical actinobacillosis affecting hind limbs and lungs in a single beef cattle herd.

Actinobacillosis usually is a sporadic infection that affects the tongue in cattle ("wooden tongue") with possible spread to the digestive tract. Two 4-year-old Rouge-des-Prés cows from a single French beef herd were referred for chronic (2-6 months) swelling and cutaneous nodules in the distal hind limbs. In addition to cutaneous signs, physical examination disclosed cachexia, lameness, lymphadenitis of the hind limbs, and pneumonia in both cows. Cytologic examination of direct skin smears was inconclusive, and no parasites were observed in examination of multiple skin scrapings. Histopathological examination of skin and lung biopsy specimens identified chronic, diffuse, severe pyogranulomatous dermatitis, associated with Splendore-Hoeppli phenomenon and intralesional Gram-negative bacteria. Cultures from skin, lymph nodes, and lungs (both cows were euthanized for welfare reasons) identified a Pasteurellaceae organism, confirmed as Actinobacillus lignieresii by partial sequencing of the rpoB gene. This report emphasizes that actinobacillosis can appear as a small outbreak in cattle with cutaneous and respiratory signs.

Long-Term Toxicity of 213Bi-Labelled BSA in Mice.

BACKGROUND: Short-term toxicological evaluations of alpha-radioimmunotherapy have been reported in preclinical assays, particularly using bismuth-213 (213Bi). Toxicity is greatly influenced not only by the pharmacokinetics and binding specificity of the vector but also by non-specific irradiation due to the circulating radiopharmaceutical in the blood. To assess this, an acute and chronic toxicity study was carried out in mice injected with 213Bi-labelled Bovine Serum Albumin (213Bi-BSA) as an example of a long-term circulating vector. METHOD: Biodistribution of 213Bi-BSA and 125I-BSA were compared in order to evaluate 213Bi uptake by healthy organs. The doses to organs for injected 213Bi-BSA were calculated. Groups of nude mice were injected with 3.7, 7.4 and 11.1 MBq of 213Bi-BSA and monitored for 385 days. Plasma parameters, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine, were measured and blood cell counts (white blood cells, platelets and red blood cells) were performed. Mouse organs were examined histologically at different time points. RESULTS: Haematological toxicity was transient and non-limiting for all evaluated injected activities. At the highest injected activity (11.1 MBq), mice died from liver and kidney failure (median survival of 189 days). This liver toxicity was identified by an increase in both ALT and AST and by histological examination. Mice injected with 7.4 MBq of 213Bi-BSA (median survival of 324 days) had an increase in plasma BUN and creatinine due to impaired kidney function, confirmed by histological examination. Injection of 3.7 MBq of 213Bi-BSA was safe, with no plasma enzyme modifications or histological abnormalities. CONCLUSION: Haematological toxicity was not limiting in this study. Liver failure was observed at the highest injected activity (11.1 MBq), consistent with liver damage observed in human clinical trials. Intermediate injected activity (7.4 MBq) should be used with caution because of the risk of long-term toxicity to kidneys.

Refractory hypoglycaemia in a dog infected with Trypanosoma congolense.

A 20 kg German shepherd dog was presented to a French veterinary teaching hospital for seizures and hyperthermia. The dog had returned 1 month previously from a six-month stay in Senegal and sub-Saharan Africa. Biochemistry and haematology showed severe hypoglycaemia (0.12 g/L), anaemia and thrombocytopenia. Despite administration of large amounts of glucose (30 mL of 30% glucose IV and 10 mL of 70% sucrose by gavage tube hourly), 26 consecutive blood glucose measurements were below 0.25 g/L (except one). Routine cytological examination of blood smears revealed numerous free extracytoplasmic protozoa consistent with Trypanosoma congolense. PCR confirmed a Trypanosoma congolense forest-type infection. Treatment consisted of six injections of pentamidine at 48-hour intervals. Trypanosomes had disappeared from the blood smears four days following the first injection. Clinical improvement was correlated with the normalization of laboratory values. The infection relapsed twice and the dog was treated again; clinical signs and parasites disappeared and the dog was considered cured; however, 6 years after this incident, serological examination by ELISA T. congolense was positive. The status of this dog (infected or non-infected) remains unclear. Hypoglycaemia was the most notable clinical feature in this case. It was spectacular in its severity and in its refractory nature; glucose administration seemed only to feed the trypanosomes, indicating that treatment of hypoglycaemia may in fact have been detrimental.

Naturally occurring melanomas in dogs as models for non-UV pathways of human melanomas.

Spontaneously occurring melanomas are frequent in dogs. They appear at the same localizations as in humans, i.e. skin, mucosal sites, nail matrix and eyes. They display variable behaviors: tumors at oral localizations are more frequent and aggressive than at other anatomical sites. Interestingly, dog melanomas are associated with strong breed predispositions and overrepresentation of black-coated dogs. Epidemiological analysis of 2350 affected dogs showed that poodles are at high risk of developing oral melanoma, while schnauzers or Beauce shepherds mostly developped cutaneous melanoma. Clinical and histopathological analyses were performed on a cohort of 153 cases with a 4-yr follow-up. Histopathological characterization showed that most canine tumors are intradermal and homologous to human rare morphological melanomas types - 'nevocytoid type' and 'animal type'-. Tumor cDNA sequencing data, obtained from 95 dogs for six genes, relevant to human melanoma classification, detected somatic mutations in oral melanoma, in NRAS and PTEN genes, at human hotspot sites, but not in BRAF. Altogether, these findings support the relevance of the dog model for comparative oncology of melanomas, especially for the elucidation of non-UV induced pathways.

Thorough investigation of a canine autoinflammatory disease (AID) confirms one main risk locus and suggests a modifier locus for amyloidosis.

Autoinflammatory disease (AID) manifests from the dysregulation of the innate immune system and is characterised by systemic and persistent inflammation. Clinical heterogeneity leads to patients presenting with one or a spectrum of phenotypic signs, leading to difficult diagnoses in the absence of a clear genetic cause. We used separate genome-wide SNP analyses to investigate five signs of AID (recurrent fever, arthritis, breed specific secondary dermatitis, otitis and systemic reactive amyloidosis) in a canine comparative model, the pure bred Chinese Shar-Pei. Analysis of 255 DNA samples revealed a shared locus on chromosome 13 spanning two peaks of association. A three-marker haplotype based on the most significant SNP (p<2.6×10(-8)) from each analysis showed that one haplotypic pair (H13-11) was present in the majority of AID individuals, implicating this as a shared risk factor for all phenotypes. We also noted that a genetic signature (F ST) distinguishing the phenotypic extremes of the breed specific Chinese Shar-Pei thick and wrinkled skin, flanked the chromosome 13 AID locus; suggesting that breed development and differentiation has played a parallel role in the genetics of breed fitness. Intriguingly, a potential modifier locus for amyloidosis was revealed on chromosome 14, and an investigation of candidate genes from both this and the chromosome 13 regions revealed significant (p<0.05) renal differential expression in four genes previously implicated in kidney or immune health (AOAH, ELMO1, HAS2 and IL6). These results illustrate that phenotypic heterogeneity need not be a reflection of genetic heterogeneity, and that genetic modifiers of disease could be masked if syndromes were not first considered as individual clinical signs and then as a sum of their component parts.

PAR-2 activation increases human intestinal mucin secretion through EGFR transactivation.

PAR-2 (protease-activated receptors-2) are G protein-coupled receptors whose action on mucin secretion by intestinal epithelial cells is still unknown. The aim of this study was to examine the effect of PAR-2 activation on mucin secretion in the human colonic goblet cell line HT29-Cl.16E and the intracellular pathways involved. We found that PAR-2 mRNA was constitutively expressed by HT29-Cl.16E cells as well as by isolated human normal colonocytes. The PAR-2-activating peptide SLIGKV-NH(2) elicited rapid mucin secretion in HT29-Cl.16E, which was partially inhibited by calcium chelator BAPTA. Inhibitors of MAPK activation (PD98059) and EGFR tyrosine kinase activity (AG1478) abrogated PAR-2-induced ERK1/2 and EGFR tyrosine phosphorylation, respectively, and subsequent mucin secretion. Finally, PAR-2-induced EGFR transactivation was involved upstream of ERK1/2 activation. Our results show that the activation of PAR-2 expressed by human intestinal epithelial cells enhances mucin secretion, a component of the intestinal innate defence, via a pathway involving EGFR transactivation.