Myxomatous mitral valve disease (MMVD) is the most common acquired cardiac disoder in dogs and a relevant model for human mitral valve disease. However, the molecular drivers of disease progression remain unclear, and reliable biomarkers for early diagnosis still hamper clinical management. This study investigated microRNA (miRNA) expression directly in histologically characterized mitral valve tissues. Formalin-fixed paraffin-embedded samples were obtained from control dogs (n = 7), low-grade MMVD (n = 8), and high-grade MMVD (n = 5). A bioinformatics workflow identified candidate miRNAs converging on extracellular matrix remodeling and canonical signaling pathways, including TGF-β, PI3K–Akt, and MAPK. Selected candidates, let-7 family, miR-98, miR-21, miR-30b, miR-133b, and miR-103, were validated by qPCR. Results revealed a general upregulation of the panel in MMVD compared with controls, with stage-dependent differences between low- and high-grade lesions. In particular, miR-21, let-7b, and miR-133b were markedly increased in advanced disease, while miR-30b emerged as an early-stage marker with potential prognostic value. These findings provide molecular evidence linking miRNA dysregulation to progressive valvular degeneration. By combining histologically defined tissue analysis with stage-based comparisons, this study identifies miRNAs with potential diagnostic and prognostic utility for canine MMVD.

Osteoarthritis (OA) is increasingly conceptualized as a whole-joint disorder, in which pathological processes across articular cartilage, subchondral bone, synovium, and periarticular tissues are tightly interconnected. Within this context, miRNAs have emerged as central post-transcriptional regulators capable of integrating mechanical, inflammatory, and metabolic cues at the network level. In human OA, extensive evidence links miRNA dysregulation to cartilage catabolism, impaired stress adaptation, inter-tissue communication, and the emergence of extracellular and circulating miRNA (cmiRNA) signatures with diagnostic and translational relevance. In contrast, miRNA research in canine OA remains limited, despite dogs developing a naturally occurring form of the disease that closely mirrors human OA in clinical presentation, joint pathology, and biomechanical drivers. To date, only a single pilot study has systematically investigated miRNA expression in spontaneous canine OA, underscoring both the feasibility of miRNA profiling and the substantial gaps that persist in tissue validation and functional characterization. This review critically synthesizes miRNA-mediated regulatory mechanisms in human OA and leverages this evidence to define research priorities in canine OA, where experimental validation remains limited. By focusing on shared molecular contexts rather than assumed equivalence, the review defines a comparative framework highlighting cmiRNAs as promising non-invasive translational targets.

The close physiological relationship between the left atrium (LA) and left ventricle (LV) suggests that an index assessing both the cardiac chambers simultaneously could provide useful information about disease severity. Consequently, investigators have proposed the atrioventricular coupling index (LACi), and demonstrated its utility in predicting the likelihood of atrial fibrillation, heart failure, and other cardiovascular events in humans. No studies have been reported in veterinary medicine. Therefore, we measured the LACi in healthy dogs and dogs affected by myxomatous mitral valve disease (MMVD). Two hundred and thirty-three dogs (105 healthy dogs and 128 dogs with MMVD) were retrospectively included in the study. The LACi (LA volume/LV volume*100) at LV end-diastole (LACi-ED) and LV end-systole (LACi-ES) of each dog was measured using a monoplane Simpson’s Method of Discs from the left apical four-chamber view. In healthy dogs, LACi-ED and LACi-ES showed no relationship with bodyweight, heart rate and age (R2 < 0.03, for all variables). In MMVD dogs, LACi-ED and LACi-ES differed between ACVIM stages (P < 0.00 and P < 0.02, for all stages). The LACi-ED and LACi-ES had similar accuracy in identifying MMVD dogs with congestive heart failure (area under the curve of 0.920 and 0.906, respectively). Our data suggest that LACi can be useful in assessing left atrioventricular function in dogs with MMVD but the diagnostic accuracy in identifying dogs with congestive heart failure was not superior to left-atrial-to-aortic ratio. Prospective studies are needed to evaluate the predictive value of this new echocardiographic index in dogs affected by MMVD.

The close physiological relationship between the left atrium (LA) and left ventricle (LV) suggests that an index assessing both the cardiac chambers simultaneously could provide useful information about disease severity. Consequently, investigators have proposed the atrioventricular coupling index (LACi) and demonstrated its utility in predicting the likelihood of atrial fibrillation, heart failure, and other cardiovascular events in humans. No studies have been reported in veterinary medicine. Therefore, we measured the LACi in healthy dogs and dogs affected by myxomatous mitral valve disease (MMVD). Two hundred and thirty-three dogs (105 healthy dogs and 128 dogs with MMVD) were retrospectively included in the study. The LACi (LA volume/LV volume × 100) at LV end-diastole (LACi-ED) and LV end-systole (LACi-ES) of each dog was measured using a monoplane Simpson’s Method of Discs from the left apical four-chamber view. In healthy dogs, LACi-ED and LACi-ES showed no relationship with bodyweight, heart rate and age (R² < 0.03, for all variables). In MMVD dogs, LACi-ED and LACi-ES differed between ACVIM stages (p < 0.001 and p < 0.02, for all stages). The LACi-ED and LACi-ES had similar accuracy in identifying MMVD dogs with congestive heart failure (area under the curve of 0.920 and 0.906, respectively). Our data suggest that the LACi can be useful in assessing left atrioventricular function in dogs with MMVD but the diagnostic accuracy in identifying dogs with congestive heart failure was not superior to the left atrial-to-aortic ratio. Prospective studies are needed to evaluate the predictive value of this new echocardiographic index in dogs affected by MMVD.

A phytobezoar is a compact mass formed by the accumulation of indigestible food fibers (such as cellulose and lignin) within the stomach and/or intestine. To date, only limited reports describe the clinical management and diagnostic approach to gastrointestinal phytobezoars (GIPs) in dogs and cats. The aim of this study was to describe the clinical features and diagnostic findings obtained through imaging and instrumental investigations in canine and feline cases with GIPs. Medical records of 25 animals diagnosed with GIPs were reviewed, and data on signalment, clinical signs, imaging findings, and follow-up were collected. Seven animals were excluded because the foreign body (FB) consisted of plastic mixed with fibrous material. Eighteen animals (17 dogs and 1 cat) were included: 8 (44.4%) with gastric involvement, 8 (44.4%) with intestinal localization and 2 (11.1%) with both gastric and intestinal localization. The GIP was removed endoscopically in 3 (16.7%) cases, surgically in 7 (38.9%) cases, extracted from the rectal ampulla in 2 (11.1%) cases, and expelled spontaneously through defecation in 6 (33.3%) cases. GIPs are frequently underdiagnosed, as they are associated with nonspecific gastrointestinal signs. Radiography and ultrasonography offer limited diagnostic value, generally suggesting the presence of an FB without definitively confirming it to be GIP. This study contributes to the current literature by detailing the clinical, diagnostic, and interventional features of GIPs in small animals, representing the first report of this condition in veterinary medicine.