Association of folate concentrations with clinical signs and laboratory markers of chronic enteropathy in dogs

Age-Related Changes in Gut Health and Behavioral Biomarkers in a Beagle Dog Population

The gut and the gut microbiome communicate with the nervous system through the gut-brain axis via neuroimmune and neuroendocrine mechanisms. Despite existing research, studies exploring this link in aging dogs are limited. This study aims to examine multiple blood and fecal biomarkers of intestinal health, along with various behavioral indicators based on saliva, blood, observations, and activity, in different age populations (junior: <2 y.o.; adult: 2-7 y.o.; senior: >7 y.o.) of thirty-seven Beagle dogs. In our study, Bacteroides were significantly higher in senior dogs. The relative abundance of Faecalibacterium and Blautia showed age-related trends, higher in senior and junior dogs, respectively. Fecal short-chain fatty acid concentration, especially acetate, increased with age, while propionate was higher in junior dogs. For the behavioral indicators we considered, blood thyroxine concentration, playing, exploring, and total activity were higher in junior dogs. The differences observed between the biomarkers of gut health and behavior, particularly those significant for the age correlations, emphasize the importance of considering age-related factors when studying the gut microbiome and behavior. However, further research is needed to better understand the mechanisms and specific pathways involved in the relationship between the studied biomarkers and age.

Expression of the cobalamin transporters cubam and MRP1 in the canine ileum-Upregulation in chronic inflammatory enteropathy

Chronic inflammatory enteropathy (CIE) in dogs, a spontaneous model of human inflammatory bowel disease (IBD), is associated with a high rate of cobalamin deficiency. The etiology of hypocobalaminemia in human IBD and canine CIE remains unknown, and compromised intestinal uptake of cobalamin resulting from ileal cobalamin receptor deficiency has been proposed as a possible cause. Here, we evaluated the intestinal expression of the cobalamin receptor subunits, amnionless (AMN) and cubilin (CUBN), and the basolateral efflux transporter multi-drug resistance protein 1 (MRP1) in 22 dogs with CIE in comparison to healthy dogs. Epithelial CUBN and AMN levels were quantified by confocal laser scanning microscopy using immunohistochemistry in endoscopic ileal biopsies from dogs with (i) CIE and normocobalaminemia, (ii) CIE and suboptimal serum cobalamin status, (iii) CIE and severe hypocobalaminemia, and (iv) healthy controls. CUBN and MRP1 expression was quantified by RT-qPCR. Receptor expression was evaluated for correlation with clinical patient data. Ileal mucosal protein levels of AMN and CUBN as well as mRNA levels of CUBN and MRP1 were significantly increased in dogs with CIE compared to healthy controls. Ileal cobalamin receptor expression was positively correlated with age, clinical disease activity index (CCECAI) score, and lacteal dilation in the ileum, inversely correlated with serum folate concentrations, but was not associated with serum cobalamin concentrations. Cobalamin receptor downregulation does not appear to be the primary cause of hypocobalaminemia in canine CIE. In dogs of older age with severe clinical signs and/or microscopic intestinal lesions, intestinal cobalamin receptor upregulation is proposed as a mechanism to compensate for CIE-associated hypocobalaminemia. These results support oral supplementation strategies in hypocobalaminemic CIE patients.