Chronic kidney disease in dogs and cats

Chemical Sensors and Biosensors for Point-of-Care Testing of Pets: Opportunities for Individualized Diagnostics of Companion Animals

Point-of-care testing (POCT) is recognized as one of the most disruptive medical technologies for rapid and decentralized diagnostics. Successful commercial examples include portable glucose meters, pregnancy tests, and COVID-19 self-tests. However, compared to advancements in human healthcare, POCT technologies for companion animals (pets) remain significantly underdeveloped. This Review explores the latest advancements in pet POCT and examines the challenges and opportunities in the field for individualized diagnostics of cats and dogs. The most frequent diseases and their respective biomarkers in blood, urine, and saliva are discussed. We examine key strategies for developing the next-generation POCT devices by harnessing the potential of selective (bio)receptors and high-performing transducers such as lateral flow tests and electrochemical (bio)sensors. We also present the most recent research initiatives and the successful commercial pet POCT technologies. We discuss future trends in the field, such the role of biomarker discovery and development of wearable, implantable, and breath sensors. We believe that advancing pet POCT technologies benefits not only animals but also humans and the environment, supporting the One Health approach.

Characterization of feline nonsteroidal anti-inflammatory drug activated gene-1 (fNAG-1) and its protective function in kidney cells

BACKGROUND

Domestic cats are susceptible to obesity and chronic renal failure, leading to significant health risks. Nonsteroidal anti-inflammatory drug-activated gene (NAG-1), also known as growth differentiation factor 15 (GDF15), is a member of the transforming growth factor-β superfamily and has been associated with anti-obesity properties and preservation of kidney function. While the NAG-1 sequence has been extensively studied in several species, a comprehensive understanding of feline NAG-1 remains limited. This study aimed to investigate the nucleotide sequence of feline NAG-1 and its biological role in kidney protection through in-vitro experiments.

METHODS

The feline NAG-1 cDNA was isolated from the feline uterus, and its sequence was analyzed and compared to sequences from other species, including humans. Expression patterns of feline NAG-1 in various tissues, particularly the liver and kidney, were determined. Furthermore, the effects of different phytochemicals and NSAIDs known to induce NAG-1 expression were assessed using Crandell-Rees Feline Kidney (CRFK) cells.

RESULTS

The analysis revealed that feline NAG-1 shares similarities with human NAG-1 and exhibits high expression levels in the liver and kidney of cats. Treatment with tolfenamic acid, quercetin, and resveratrol significantly increased NAG-1 expression in CRFK cells. Subsequently, CRFK cells overexpressing feline NAG-1 were utilized to investigate the functional roles of NAG-1 in feline kidney health. High-content screening analysis demonstrated that NAG-1 overexpression in cat kidney cells enhanced mitochondrial membrane potential, reduced reactive oxygen species (ROS) generation in both whole cells and mitochondria, and downregulated the expression of Bax, a pro-apoptotic protein, under conditions of ROS-induced stress. These findings indicate the renoprotective role of NAG-1.

CONCLUSION

This study highlights the significant role of NAG-1 in feline kidney cells, revealing its high expression in the liver and kidney and demonstrating its protective effects on kidney function. These results underscore the potential of NAG-1 as a key factor in kidney protection. Future research should focus on further elucidating the molecular pathways involved and exploring therapeutic strategies to harness NAG-1 for managing obesity-related renal dysfunction in cats.

Concurrent pancreatic exocrine hyperplasia and adenomas in a Eurasian otter with pleuropneumonia and urolithiasis

The Eurasian otter (Lutra lutra) is a semi-aquatic mammal classified as near-threatened by the International Union for Conservation of Nature. There have been few reports on their diseases, especially neoplasms. Here we describe exocrine nodular hyperplasia and adenomas in the pancreas, along with suppurative pleuropneumonia and urolithiasis, in an aged captive Eurasian otter. Pancreatic adenomas are rare in animals, and coexistence of adenoma and nodular hyperplasia in the pancreas has not been reported previously in veterinary medicine, to our knowledge.

Volumetric absorptive microsampling to measure iohexol and creatinine concentrations for estimation of glomerular filtration rate in cats: aligning animal welfare with practical feasibility

BACKGROUND

Chronic kidney disease (CKD) is common in cats, and early detection is crucial for better prognosis. Currently, the gold standard to assess renal function is the measurement of glomerular filtration rate (GFR), allowing early detection of decreased kidney function. To overcome the practical limitations of this procedure, microsampling, collecting a small drop of blood from the cat's ear, can be used. Application of volumetric absorptive microsampling (VAMS) in feline nephrology would be of tremendous value, aligning with animal welfare and improving practical feasibility of GFR measurements.

RESULTS

We developed and successfully validated liquid chromatography - tandem mass spectrometry (LC-MS/MS) methods to simultaneously determine iohexol and creatinine in plasma, blood and VAMS samples. A clinical validation study, conducted in 23 cats from whom conventional venous blood, plasma and VAMS samples were collected, allowed to establish a conversion formula to derive plasma iohexol or creatinine concentrations from capillary VAMS concentrations. This conversion was applied on an independent set, revealing an excellent agreement for both iohexol and creatinine between concentrations directly measured in venous plasma or derived from ear-prick VAMS samples (94% and 96% of differences lay < 20%, respectively).

CONCLUSIONS

We demonstrated that ear-prick sampling using VAMS is a suitable alternative to conventional venous sampling to measure iohexol and creatinine for GFR determination in cats.

The Emerging Role of Water Loss in Dog Aging

Aging involves progressive physiological changes, including the dysregulation of water homeostasis, essential for cellular function, neuronal signaling, and musculoskeletal integrity. This review explores the emerging role of water loss as a central and underestimated driver of functional decline in aging, with a focus on the dog, both as a clinically relevant target species and as a model for human aging. Age-related alterations in water metabolism-driven by changes in body composition, aquaporin (AQP) expression, electrolyte imbalances, reduced thirst perception, and impaired urine concentration-lead to intracellular and extracellular dehydration, exacerbating functional decline. We examine molecular mechanisms of water regulation involving AQPs and osmolytes, and describe how dehydration contributes to structural and metabolic dysfunction across key biological compartments, including the kidney, brain, bone, and skeletal muscle. Physiological dehydration, a hallmark of aging, intensifies inflammaging, accelerating tissue degeneration. In particular, we highlight how water loss impairs solvent capacity, solute transport, protein conformation, and cellular communication. Despite the known role of macronutrients in geriatric nutrition, hydration remains an often-overlooked factor in aging management. We argue for its inclusion as a fourth pillar in the nutritional approach to veterinary geriatrics, alongside protein, fat, and fiber. By investigating aging-associated water loss in dogs-species that share environments and lifestyle patterns with humans-we propose hydration-centered strategies to promote healthy aging in both veterinary and comparative medicine.

Parathyroid Hormone Concentration in Dogs Affected by Acute Kidney Injury Compared with Healthy and Chronic Kidney Disease

Information about parathyroid hormone (PTH) status in the course of AKI is lacking. In contrast, renal secondary hyperparathyroidism (RSHPT) is a well-known consequence of canine chronic kidney disease (CKD). This study aimed to investigate PTH status in dogs affected by AKI, comparing PTH concentrations between healthy dogs, dogs affected by AKI and dogs affected by CKD. Three groups of dogs (35 affected by AKI, 35 affected by CKD and 41 healthy) were retrospectively included. PTH concentrations were significantly higher in both the AKI and CKD groups (p < 0.0001) compared to healthy ones but without significant differences between the AKI and CKD groups. In the AKI group, increased PTH was detected in 88.6% of dogs. Moreover, in AKI dogs, PTH increases with AKI grading and is correlated with serum creatinine (p < 0.0001; r = 0.67) and phosphate concentrations (p < 0.0001; r = 0.74). PTH in AKI dogs was not correlated with total calcium (tCa), while it was negatively correlated with ionized calcium (iCa) (p < 0.0037; r = -0.53). Higher PTH concentrations also occurred in canine AKI, as reported in canine CKD and human AKI, presumably as a rapid response to ionized hypocalcemia and hyperphosphatemia, frequently reported in our patients. PTH seems not to be a useful tool in distinguishing AKI and CKD.

Recent Issues in the Development and Application of Targeted Therapies with Respect to Individual Animal Variability

This literature review explores the impact of molecular, genetic, and environmental factors on the efficacy of targeted therapies in veterinary medicine. Relevant studies were identified through systematic searches of PubMed, Web of Science, Scopus, and ScienceDirect using keywords such as "species-specific treatment strategies", "signalling pathways", "epigenetic and paragenetic influences", "targeted therapies", "veterinary medicine", "genetic variation", and "free radicals and oxidative stress". Inclusion criteria included studies focusing on species-specific therapeutic responses, genetic influences, and oxidative stress. To ensure that only the most recent and relevant evidence was included, only peer-reviewed publications from the last two decades were considered. Each study selected for analysis was critically appraised, with a particular emphasis on methodological quality, experimental design, and scientific contribution to the understanding of how environmental and biological factors influence therapeutic outcomes. A special emphasis was placed on studies that used a comparative, cross-species approach to assess variability in therapeutic responses and potential adverse effects. The review synthesises evidence on the role of epigenetic and paragenetic factors and highlights the importance of cross-species studies to understand how environmental and biological factors influence treatment outcomes. By highlighting genetic variation, oxidative stress, and individual species differences, the review argues for personalised and species-specific therapeutic approaches. The review emphasises that such an approach would improve veterinary care and inform future research aimed at optimising targeted therapies, ultimately leading to better animal health and treatment efficacy. A key contribution of the review is its emphasis on the need for more personalised treatment protocols that take into account individual genetic profiles and environmental factors; it also calls for a greater integration of cross-species studies.

Blood pressure and proteinuria in older cats and cats with chronic kidney disease

Background and Aim

Systemic hypertension and proteinuria are key prognostic indicators in cats with chronic kidney disease (CKD). However, their interrelationship in older cats and those with CKD remains unclear. This study aimed to investigate the association between systolic blood pressure (SBP) and proteinuria in older cats and cats with CKD and evaluate the correlation of these parameters with hematological and biochemical markers.

Materials and Methods

A cross-sectional observational study was conducted on 51 cats divided into three groups: 19 young adult cats (1-6 years, G1), 19 older cats (>10 years, G2), and 13 cats with CKD (creatinine >1.6 mg/dL, G3). Cats underwent clinical evaluations, blood pressure measurements using the oscillometric method, electrocardiography, and hematological, serum, and urine biochemical analyses. Statistical analyses included bootstrapped t-tests and Spearman's correlation, with significance set at p < 0.05.

Results

SBP values did not significantly differ among groups, but absolute SBP values were higher in older cats (G2), suggesting a potential age-related trend. No significant correlations were found between SBP and proteinuria, creatinine, urea, or urine density in G2 and G3. However, kidney injury biomarkers (urinary protein-to-creatinine ratio, creatinine, and urea) were strongly correlated with weight, body score, and total plasma protein in CKD cats (G3), indicating disease progression. Furthermore, G3 exhibited significant reductions in hematocrit, hemoglobin, and red blood cell counts, which were associated with kidney dysfunction.

Conclusion

This study did not find a direct correlation between SBP and proteinuria in older cats or cats with CKD. However, the higher SBP values in older cats highlight the importance of monitoring hypertension in aging felines. In addition, proteinuria was significantly associated with declining body condition and biochemical markers of kidney dysfunction, reinforcing its value as a prognostic indicator in CKD. Further studies are needed to explore the role of proteinuria and hypertension in advanced CKD stages.

The Erythrocyte Sedimentation Rate (ESR) in Veterinary Medicine: A Focused Review in Dogs and Cats

The erythrocyte sedimentation rate (ESR) measures the rate at which erythrocytes aggregate and sediment in a fixed time in an anticoagulated blood tube and is expressed as a speed (mm/h). The ESR is still widely used in human medicine mainly as a modified or alternate method to the original Westergren. In veterinary medicine, it was employed in the 1940s-1960s after which it was gradually abandoned or rarely employed. More papers using the Westergren method have been published in dogs rather than in cats. In recent years, the test has regained importance. This narrative review describes the principle of ESR, which is related to the increase in a few acute response proteins such as fibrinogen, immunoglobulin M, and α2-macroglobulin which act to aggregate RBCs. Reference intervals were established for dogs and cats for the original and modified Westergren method. The ESR is mainly used to detect inflammatory conditions derived from infection, urinary or orthopedic disorders, and also miscellaneous diseases. The application of the modified ESR is supported by appropriate reference intervals; however, further studies are needed to assess the influence of age, sex, and breed both for dogs and cats.

Characterization of Urine-Derived Stromal/Stem Cells from Healthy Dogs and Dogs Affected by Chronic Kidney Disease (CKD)

Urine-derived mesenchymal stromal/stem cells (USCs) could be a valuable source of cells in regenerative medicine because urine can be easily collected non-invasively. In this paper, USCs were isolated from both healthy dogs and dogs affected by chronic kidney disease (CKD), and the efficacy of collection methods (spontaneous micturition, bladder catheterization, and cystocentesis) were compared. Isolated cells were cultured in the presence of platelet-rich plasma and studied for their proliferative capacity (growth curve, doubling time, and colony forming unit), differentiation properties, expression of mesenchymal markers, and Klotho protein. Morphologically, all cells were elongated and fibroblast-like. USCs isolated from samples collected by spontaneous micturition and bladder catheterization failed to proliferate, whilst USCs obtained by cystocentesis showed a doubling time of 2.04 days in healthy dogs and 1.7 days in dogs with CKD (p < 0.05). Cells were able to differentiate into osteogenic, chondrogenic, and adipogenic lines, showed positive expression to mesenchymal/stem markers, negative expression to hematopoietic markers, and major histocompatibility complex (MHCII) antigen. Klotho protein expression was confirmed. This study confirmed that USCs from healthy and CKD dogs can act as stem cells, with those from sick dogs having greater proliferative ability with the potential for use as autologous therapies.

Serum concentrations of IL-1β, IL-6, and TNF-α in dogs with chronic kidney disease in uremic syndrome undergoing intermittent hemodialysis with and without bypass

Intermittent hemodialysis (IH) is an important therapy in the context of kidney dysfunction in dogs. However, its impact on pro-inflammatory cytokines is unclear. This study assessed IL-1β, IL-6, and TNF-α serum concentrations in dogs with chronic kidney disease (CKD) undergoing one session of IH without bypass (IH group, n = 4) and with bypass (IH + bypass group, n = 4). The control group (CG) included four healthy dogs. Cytokine levels were measured before, during, and after the first IH session. Comparative analyses of each cytokine within each group and time point were performed, along with a global comparison between groups. No significant changes were observed in cytokines across evaluation times in the IH groups. IL-1β was significantly higher post-session in the IH and IH + bypass groups compared to CG. Globally, IL-1β and TNF-α concentrations were significantly higher in the IH (11.41 pg/mL (10-16.17) and 2 pg/mL (2-88.54), respectively) and IH + bypass groups (10 pg/mL (10-10) and 2 pg/mL (2-215.5), respectively) compared to CG (0.96 pg/mL (0-3.56) and 0 pg/mL (0-0.003), respectively). The IH group also showed elevated IL-6 concentration (0.1 ng/mL (0.1-0.5)) compared to CG (0 ng/mL (0-0.1)). Higher IL-1β and IL-6 concentrations were observed in the IH group (11.41 pg/mL (10-16.17) and 0.1 ng/mL (0.1-0.1), respectively) compared to the IH + bypass group (10 pg/mL (10-10) and 0.1 ng/mL (0.1-0.5), respectively). In conclusion, a single IH session, with or without bypass, did not increase pro-inflammatory cytokines in CKD dogs with uremic syndrome but maintained the inflammatory state. Dogs undergoing IH without bypass may receive a stronger stimulus for cytokine release.

Evaluation of chronic stress status and quality of life in cats suffering from chronic kidney disease and suspected feline infectious peritonitis based on hair cortisol concentration analysis and a questionnaire

Hair cortisol concentration (HCC) and a questionnaire were used as indicators of chronic stress status and quality of life (QoL), respectively, in cats. To date, there has been limited research on the simultaneous application of both indicators in unwell cats. Our aim was to evaluate HCC and questionnaire data obtained from a healthy cat cohort (n = 61) and cat cohorts with either chronic kidney disease (CKD) (n = 78) or suspected feline infectious peritonitis (FIP) (n = 24). Furthermore, we also investigated the correlation between HCC and clinical pathological data. For this study, hair from the abdomen of cats was collected and analyzed for HCC using a commercial ELISA kit. Owners also completed a questionnaire, from which average-item-weighted-impact-scores (AWISs) were calculated. Cats with late-stage-CKD (median, HCC = 330.15 pg/mg, AWIS = -0.43) presented with a significantly higher HCC (p < 0.01) and a significantly lower AWIS (p < 0.01) than cats with early-stage-CKD (HCC = 183.56 pg/mg, AWIS = 1.08). Similarly, there were significant differences in both HCC (p < 0.001) and AWIS (p < 0.001) between cats with suspected FIP (HCC = 896.27 pg/mg, AWIS = -1.97) and healthy cats (HCC = 181.24 pg/mg, AWIS = 1.24). The degree of consistency between the HCC results and the questionnaire results reminds us that the severity of a chronic disease or the presence of a life-threatening disease can significantly increase stress and thus can affect the QoL of cats.

Renal Disease in Cats and Dogs-Lessons Learned from Text-Mined Trends in Humans

Chronic kidney disease (CKD) is characterised by progressive kidney damage and encompasses a broad range of renal pathologies and aetiologies. In humans, CKD is an increasing global health problem, in particular in the western world, while in cats and dogs, CKD is one of the leading causes of mortality and morbidity. Here, we aimed to develop an enhanced understanding of the knowledge base related to the pathophysiology of renal disease and CKD in cats and dogs. To achieve this, we leveraged a text-mining approach for reviewing trends in the literature and compared the findings to evidence collected from publications related to CKD in humans. Applying a quantitative text-mining technique, we examined data on clinical signs, diseases, clinical and lab methods, cell types, cytokine, and tissue associations (co-occurrences) captured in PubMed biomedical literature. Further, we examined different types of pain within human CKD-related publications, as publications on this topic are sparser in companion animals, but with the growing importance of animal welfare and quality of life, it is an area of interest. Our findings could serve as substance for future research studies. The systematic automated review of relevant literature, along with comparative analysis, has the potential to summarise scientific evidence and trends in a quick, easy, and cost-effective way. Using this approach, we identified targeted and novel areas of investigation for renal disease in cats and dogs.

Diagnostic validation of the urine albumin-to-creatinine ratio for early renal disease in healthy dogs and dogs with chronic kidney disease

IMPORTANCE

This paper highlights the urine albumin-to-creatinine ratio (UAC) as a valuable biomarker for the early detection of chronic kidney disease (CKD) in dogs. The UAC effectively distinguishes between healthy dogs and those with CKD, particularly in the early stages, and enhances diagnostic accuracy when used alongside other renal biomarkers.

OBJECTIVE

To evaluate the utility of the UAC as a biomarker for early CKD diagnosis in dogs and examine its correlation with other renal biomarkers in a large-scale clinical study.

METHODS

This study included 99 healthy dogs and 122 dogs with CKD. The UAC and other renal biomarkers were measured and evaluated in healthy dogs and those with CKD and categorized according to the staging criteria of the International Renal Interest Society (IRIS).

RESULTS

Dogs with CKD had significantly higher UACs than healthy dogs (p < 0.05). The UAC correlated with the IRIS stages and other renal biomarkers (p < 0.05). Receiver operating characteristic curve analysis yielded an area under the curve of 0.817 (p < 0.05) for the UAC, with a cut-off value of 19.20 mg/g, showing 72% sensitivity and 71% specificity. A "grey zone" diagnostic window for early-stage CKD was introduced.

CONCLUSIONS AND RELEVANCE

The UAC is effective for the early diagnosis of renal disease in dogs. The UAC can differentiate between healthy dogs and those with CKD at IRIS stage 1. The diagnostic value is enhanced when used alongside other renal biomarkers, allowing for more specific guidelines for pet owners and veterinarians. This large-scale study addresses the limitations of previous research conducted on small clinical samples.

Fecal bile acid dysmetabolism and reduced ursodeoxycholic acid correlate with novel microbial signatures in feline chronic kidney disease

Background

Microbial-derived secondary bile acids (SBAs) are reabsorbed and sensed via host receptors modulating cellular inflammation and fibrosis. Feline chronic kidney disease (CKD) occurs with progressive renal inflammation and fibrosis, mirroring the disease pathophysiology of human CKD patients.

Methods

Prospective cross-sectional study compared healthy cats (n = 6) with CKD (IRIS Stage 2 n = 17, Stage 3 or 4 n = 11). Single timepoint fecal samples from all cats underwent targeted bile acid metabolomics. 16S rRNA gene amplicon sequencing using DADA2 with SILVA taxonomy characterized the fecal microbiota.

Results

CKD cats had significantly reduced fecal concentrations (median 12.8 ng/mg, Mann-Whitney p = 0.0127) of the SBA ursodeoxycholic acid (UDCA) compared to healthy cats (median 39.4 ng/mg). Bile acid dysmetabolism characterized by <50% SBAs was present in 8/28 CKD and 0/6 healthy cats. Beta diversity significantly differed between cats with <50% SBAs and > 50% SBAs (PERMANOVA p < 0.0001). Twenty-six amplicon sequence variants (ASVs) with >97% nucleotide identity to Peptacetobacter hiranonis were identified. P. hiranonis combined relative abundance was significantly reduced (median 2.1%) in CKD cats with <50% SBAs compared to CKD cats with >50% SBAs (median 13.9%, adjusted p = 0.0002) and healthy cats with >50% SBAs (median 15.5%, adjusted p = 0.0112). P. hiranonis combined relative abundance was significantly positively correlated with the SBAs deoxycholic acid (Spearman r = 0.5218, adjusted p = 0.0407) and lithocholic acid (Spearman r = 0.5615, adjusted p = 0.0156). Three Oscillospirales ASVs and a Roseburia ASV were also identified as significantly correlated with fecal SBAs.

Clinical and translational importance

The gut-kidney axis mediated through microbial-derived SBAs appears relevant to the spontaneous animal CKD model of domestic cats. This includes reduced fecal concentrations of the microbial-derived SBA UDCA, known to regulate inflammation and fibrosis and be reno-protective. Microbes correlated with fecal SBAs include bai operon containing P. hiranonis, as well as members of Oscillospirales, which also harbor a functional bai operon. Ultimately, CKD cats represent a translational opportunity to study the role of SBAs in the gut-kidney axis, including the potential to identify novel microbial-directed therapeutics to mitigate CKD pathogenesis in veterinary patients and humans alike.

Exploring frailty in apparently healthy senior dogs: a cross-sectional study

BACKGROUND

As dogs age, they face various health challenges, and preventive care may be overlooked, impacting their quality of life. Frailty, a concept established in human medicine, has recently been applied to dogs using validated tools like the frailty index and frailty phenotype. This study aims to characterize frailty in senior pet dogs and investigate associated factors. To achieve this goal, 88 apparently healthy dogs, as reported by their owners, voluntarily participated in thorough consultations. These consultations included supplementary examinations such as urinary analyses, hematological assessments, and blood biochemistry. Additionally, owners completed questionnaires addressing their dog's overall health, cognitive and locomotor status, as well as their own attachment to the dog and personality traits. Subsequently, each dog was classified as robust or frail based on the presence of multiple criteria out of a set of five. All collected data underwent preliminary screening by a multiple factorial analysis, followed by binomial logistic regression to model frailty.

RESULTS

The final population consisted of 74 dogs, with a frailty prevalence of 41.9% (95% CI: 30.5 - 53.9). In the statistical analysis, older age of the dog, lower owner attachment score, lack of regular deworming, and a disparity in extraversion between owner and dog were identified as contributing factors to frailty.

CONCLUSIONS

This study emphasizes the importance of regular deworming and strong owner-pet attachment in reducing frailty in dogs. It underscores the significance of proactive pet care and highlights the complex relationship between owner-dog personalities and canine frailty. This research advocates for a holistic approach that considers both human and canine traits to promote better health outcomes.

Deep learning-based ultrasonographic classification of canine chronic kidney disease

Objectives

In veterinary medicine, attempts to apply artificial intelligence (AI) to ultrasonography have rarely been reported, and few studies have investigated the value of AI in ultrasonographic diagnosis. This study aimed to develop a deep learning-based model for classifying the status of canine chronic kidney disease (CKD) using renal ultrasonographic images and assess its diagnostic performance in comparison with that of veterinary imaging specialists, thereby verifying its clinical utility.

Materials and methods

In this study, 883 ultrasonograms were obtained from 198 dogs, including those diagnosed with CKD according to the International Renal Interest Society (IRIS) guidelines and healthy dogs. After preprocessing and labeling each image with its corresponding IRIS stage, the renal regions were extracted and classified based on the IRIS stage using the convolutional neural network-based object detection algorithm You Only Look Once. The training scenarios consisted of multi-class classification, categorization of images into IRIS stages, and four binary classifications based on specific IRIS stages. To prevent model overfitting, we balanced the dataset, implemented early stopping, used lightweight models, and applied dropout techniques. Model performance was assessed using accuracy, recall, precision, F1 score, and receiver operating characteristic curve and compared with the diagnostic accuracy of four specialists. Inter- and intra-observer variabilities among specialists were also evaluated.

Results

The developed model exhibited a low accuracy of 0.46 in multi-class classification. However, a significant performance improvement was observed in binary classifications, with the model designed to distinguish stage 3 or higher showing the highest accuracy of 0.85. In this classification, recall, precision, and F1 score values were all 0.85, and the area under the curve was 0.89. Compared with radiologists, whose accuracy ranged from 0.48 to 0.62 in this experimental scenario, the AI model exhibited superiority. Intra-observer reliability among radiologists was substantial, whereas inter-observer variability showed a moderate level of agreement.

Conclusions

This study developed a deep-learning framework capable of reliably classifying CKD IRIS stages 3 and 4 in dogs using ultrasonograms. The developed framework demonstrated higher accuracy than veterinary imaging specialists and provided more objective and consistent interpretations. Therefore, deep-learning-based ultrasound diagnostics are potentially valuable tools for diagnosing CKD in dogs.

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.

Causes of shelter cats mortality in the Czech Republic

Awareness of the causes of mortality in shelter cats can contribute to its effective reduction. The aim of this study was to investigate the causes of mortality in cat shelters in the Czech Republic, taking into account the age of the animals and their length of stay in the shelter facilities until natural death or euthanasia. A cooperation with two private no-kill shelters in the Czech Republic was established. The subject of the study were records of 3047 cats admitted to the selected shelters in the period from 2013 to 2023. A total of 357 (11.7 %) out of 3047 cats died or had to be euthanized in two monitored shelters. No significant difference (p > 0.05) in the cat mortality was found between the two shelters (11.5 % and 12 %). The median length of stay of cats in the shelter until death or euthanasia was 23 days. The highest mortality was recorded in the youngest cats (≤ 6 months). The most common causes of death or euthanasia of cats in both shelters were feline infectious peritonitis (21.6 %), panleukopenia (18.5 %) and upper and lower respiratory tract infections (17.5 %). Adult and older cats were significantly (p < 0.05) more prone to death due to renal failure and cancer than young animals and kittens. The results of the study contribute to the knowledge on the health of cat population in shelters in the Czech Republic and can serve as a basis for further work that will target mortality reduction strategies in at-risk categories.

Bilateral Global Nephrocalcinosis in a Uremic Puppy

This study explores kidney disease in young dogs, focusing on early diagnosis, management, and the importance of staging for effective treatment. Highlighting mineral metabolism imbalances and complications such as nephrocalcinosis, the study presents a case of severe renal failure with uremic syndrome and bilateral nephrocalcinosis in a 50-day-old puppy. Despite intensive care, the puppy's condition deteriorated rapidly, leading to euthanasia. The study underscores the challenges in diagnosing and managing canine nephrocalcinosis in young animals. It emphasizes the need for further research to improve the understanding and treatment outcomes in such cases, ultimately enhancing the quality of life for animals suffering from this rare condition.

Determination of the reference interval for urinary klotho to creatinine ratio of healthy dogs

For several years, alpha klotho has been considered as a candidate biomarker in chronic kidney disease (CKD), progression of CKD and CKD mineral bone disorders (CKD-MBD). The evidence on the relationship between klotho and kidney function is controversial in some areas. The aim of the study was to identify the influence of age, sex and breed on urinary alpha klotho, values in the early stages of CKD within the studied population and determine a reference interval in a group of healthy dogs. Significantly higher values were measured in older dogs over 6 years old (p = 0.026, p = 0.0007) and in the breed German Shepherd than Belgian Shepherd (p = 0.0401). On the basis of sex and in small breed dogs, no significant differences were noted. In dogs with CKD stage 2, alpha klotho values were significantly lower (p = 0.0135) than in healthy dogs. Within the studied population, a reference interval for urinary klotho to creatinine ratio (UrKl/Cr) was determined in the range of 3.94-23.55 pg/gCr. Since our findings show that alpha klotho is associated with older age, we assume that this may have influenced the results in the group of dogs with CKD stage 1 due to the presence of predominantly old dogs in this group. Future studies would be needed to consider age as a factor affecting urinary alpha klotho in dogs with CKD.

Value of repeated health screening in 259 apparently healthy mature adult and senior cats followed for 2 years

BACKGROUND

Although regular health screening is recommended, long-term follow-up data in healthy aged cats are lacking.

OBJECTIVES

Determine the most common conditions in a large group of apparently healthy older cats and which diseases are manifested within 2 years in cats confirmed to be healthy based on extensive health screening.

ANIMALS

Client-owned cats.

METHODS

Prospective study. Thorough history, physical examination, blood tests, and urinalysis were performed in 259 apparently healthy mature adult (7-10 years) and senior (>10 years) cats. Semi-annual follow-up examinations were performed in 201 confirmed healthy cats.

RESULTS

At baseline, 21% of apparently healthy cats were not considered healthy but were diagnosed with International Renal Interest Society (IRIS) ≥ stage 2 chronic kidney disease (CKD; 7.7%) or hyperthyroidism (4.6%), among other disorders. Disease occurred significantly more frequently in senior cats compared with mature adult cats. In addition, 40% cats were overweight, 35% had moderate to severe dental disease, and 22% had abnormal cardiac auscultation findings. Within 2 years, 28% of mature adult and 54% of senior cats that were confirmed healthy at inclusion developed new diseases, most commonly IRIS ≥ stage 2 CKD (cumulative incidence, 13.4%), hyperthyroidism (8.5%), chronic enteropathy, hepatopathy or pancreatitis (7.5%), or neoplasia (7%).

CONCLUSIONS AND CLINICAL IMPORTANCE

The high prevalence and 2-year incidence of physical examination abnormalities and systemic diseases in apparently healthy older cats argue for regular health screening in cats ≥7 years of age. Although more common in senior cats, occult disease also occurs in mature adult cats, and owners should be informed accordingly.

Urinary angiotensin-converting enzyme 2 and its activity in cats with chronic kidney disease

Introduction

Angiotensin-converting enzyme 2 (ACE2) played an important role in the renin-angiotensin-aldosterone system (RAAS) and it was proved to be renoprotective in renal disease. Urinary angiotensin-converting enzyme 2 (uACE2) has been shown to reflect renal injury in human and experimental studies, but its role in feline kidney disease remains unknown.

Aims

Our objectives involve comparing uACE2 concentrations and activities in cats across CKD stages with healthy controls, investigating the relationship between uACE2 concentrations, activities, and clinicopathological data in feline CKD patients, and assessing the predictive abilities of both for CKD progression.

Methods

A retrospective, case-control study. The concentration and activity of uACE2 were measured by commercial ELISA and fluorometric assay kits, respectively. The concentration was adjusted to give uACE2 concentration-to-creatinine ratios (UACCRs).

Results

In total, 67 cats consisting of 24 control and 43 chronic kidney disease (CKD), including 24 early-stage CKD and 19 late-stage CKD, were enrolled in this study. UACCR values were significantly higher in both early-stage (2.100 [1.142-4.242] x 10-6) and late-stage feline CKD (4.343 [2.992-5.0.71] x 10-6) compared to healthy controls (0.894 [0.610-1.076] x 10-6; p < 0.001), and there was also significant difference between-early stage group and late-stage group (p = 0.026). Urinary ACE2 activity (UAA) was significantly lower in CKD cats (1.338 [0.644-2.755] x pmol/min/ml) compared to the healthy cats (7.989 [3.711-15.903] x pmol/min/ml; p < 0.001). UACCR demonstrated an independent, positive correlation with BUN (p < 0.001), and UAA exhibited an independent, negative correlation with plasma creatinine (p < 0.001). Both UACCR and UAA did not yield significant results in predicting CKD progression based on the ROC curve analysis.

Conclusion and clinical importance

uACE2 concentration and activity exhibit varying changes as renal function declines, particularly in advanced CKD cats.

PKD1 gene mutation and ultrasonographic characterization in cats with renal cysts

Background

Polycystic kidney disease (PKD) has a complex phenotype partly explained by genetic variants related to this disease. Ultrasonography is a promising approach for defining clinical signs. This study aimed to assess kidney characteristics in cats with Polycystin-1 (PKD1) gene mutations and wild-type cats. Kidney characteristics were identified by ultrasonography.

Methods

A total of 108 cats of variable breeds aged an average of 37.01±3.50 months were included. Blood examination and biochemical tests were evaluated. For cystic formation, renal ultrasound was performed. The PKD1 gene mutation was identified via polymerase chain reaction (PCR) and DNA sequencing. Matrix correlation and effectiveness of ultrasound for PKD1 mutation detection were determined.

Results

The results showed that 19.44% of cats had PKD1 mutations, a high prevalence in Persian and Persian-related breed cats. Our results demonstrated the characteristics of kidneys in wild-type cats and cats with gene mutations. Based on ultrasonography results, there was an association between cats with gene mutations and cyst formation. The findings indicated that ultrasound did not detect cysts in cats aged 4-36 months, supporting the evidence that PKD1 gene mutations may not be present. This study found high sensitivity and renal specificity ultrasound for PKD1 heterozygous mutation. Moreover, cystic formation via renal ultrasound showed an increased risk for PKD1 mutation 2,623 times compared to normal kidneys.

Conclusions

Ultrasonographic examination, coupled with genetic investigations, may help to clarify the phenotypic variability of PKD1. The phenotypic profile of PKD1 will guide therapeutic outcomes and reduce the prevalence of PKD morbidity and mortality in cats.

Investigating the Efficacy of Kidney-Protective Lactobacillus Mixture-Containing Pet Treats in Feline Chronic Kidney Disease and Its Possible Mechanism

Microbiota-based strategies are a novel auxiliary therapeutic and preventative way of moderating chronic kidney disease (CKD). Lactobacillus mixture (Lm) was previously demonstrated to exert a renal-protective function in the CKD mice model. The efficacy of probiotics in pet foods is a relatively new area of study, and thus verifying the potential health benefits is necessary. This study evaluated the efficacy of Lm treats in feline CKD and elucidated the mechanisms underlying host-microbe interactions. CKD cats (2 and 3 stages) were administrated probiotic pet treats daily (10 g) for 8 weeks. The results demonstrated that during the eight weeks of Lm administration, creatinine was reduced or maintained in all cats with CKD. Similarly, gut-derived uremic toxin (GDUT), indoxyl sulfate (IS), were potential clinical significance in IS after Lm treatment (confidence intervals = 90%). The life quality of the cats also improved. Feline gut microbiome data, metabolic functional pathway, and renal function indicator analyses revealed the possible mechanisms involved in modulating CKD feline microbial composition. Further regulation of the microbial functions in amino acid metabolism after Lm administration contributed to downregulating deleterious GDUTs. The current study provides potential adjuvant therapeutic insights into probiotic pet foods or treats for pets with CKD.

Functions and Metabolism of Amino Acids in Bones and Joints of Cats and Dogs

The bone is a large and complex organ (12-15% of body weight) consisting of specialized connective tissues (bone matrix and bone marrow), whereas joints are composed of cartilage, tendons, ligaments, synovial joint capsules and membranes, and a synovial joint cavity filled with synovial fluid. Maintaining healthy bones and joints is a dynamic and complex process, as bone deposition (formation of new bone materials) and resorption (breakdown of the bone matrix to release calcium and phosphorus) are the continuous processes to determine bone balance. Bones are required for locomotion, protection of internal organs, and have endocrine functions to maintain mineral homeostasis. Joints are responsible for resisting mechanical stress/trauma, aiding in locomotion, and supporting the overall musculoskeletal system. Amino acids have multiple regulatory, compositional, metabolic, and functional roles in maintaining the health of bones and joints. Their disorders are prevalent in mammals and significantly reduce the quality of life. These abnormalities in companion animals, specifically cats and dogs, commonly lead to elective euthanasia due to the poor quality of life. Multiple disorders of bones and joints result from genetic predisposition and are heritable, but other factors such as nutrition, growth rate, trauma, and physical activity affect how the disorder manifests. Treatments for cats and dogs are primarily to slow the progression of these disorders and assist in pain management. Therapeutic supplements such as Cosequin and formulated diets rich in amino acids are used commonly as treatments for companion animals to reduce pain and slow the progression of those diseases. Also, amino acids (e.g., taurine, arginine, glycine, proline, and 4-hydroxyproline), and glucosamine reduce inflammation and pain in animals with bone and joint disorders. Gaining insight into how amino acids function in maintaining bone and joint health can aid in developing preventative diets and therapeutic supplementations of amino acids to improve the quality of life in companion animals.

Investigating Owner Use of Dietary Supplements in Dogs with Canine Cognitive Dysfunction

Canine cognitive dysfunction (CCD) is becoming increasingly recognized in veterinary medicine, as dogs live longer and with CCD being highly prevalent among the elderly dog population. Various studies have shown that diet and dietary supplementation can positively influence the clinical signs of CCD, especially if given at an early stage. The aim of this study was to investigate owner use of dietary supplements (DSs) in dogs with age-related behavioral changes. An observational study based on an online questionnaire for owners of dogs with age-related behavioral changes was performed. Out of a total of 394 owners who completed the survey, after noticing age-related behavioral changes, over half of the dogs received DSs (54%), whereas only 8% reported changing their dog's base diet. The most used DS was fish oil (48%). The use of DSs should be discussed with and monitored by veterinary surgeons since many geriatric patients have multi-morbidities, may have specific nutritional requirements and receive multi-faceted medications.

Rapid identification of canine uropathogens by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry and the clinical factors that correlated bacterial species and antimicrobial resistance

Using the matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) method for bacterial diagnosis, rapid urine sample preparation can reduce time relapsing of diagnosis and improve discriminatory power in coinfection cases. We aimed to evaluate rapid urine preparation procedures before MALDI-TOF MS application using dog clinical urine samples in comparison with standard microbiological diagnostic methods by agreement analysis. We determined the frequency and distribution of bacteria and bacterial resistance and their correlations to clinical history. Three experimental procedures comprising direct centrifugation, 10% sodium dodecyl sulfate digestion, and ultrasonic preparation were performed for method validation and sensitivity. Sterile urine containing Escherichia coli and/or Staphylococcus aureus were used as simulated samples. By ultrasonic preparation, the microorganisms could be detected 1.46-1.51 × 105 CFU, which was considered the most suitable technique. This preparation was significantly consistent with the routine method based on data from Hospital Information Systems for 50 urine samples from canine cystitis. By standard protocol, Enterobacteriaceae and Staphylococcus pseudintermedius were found in most of the 155 urine samples with cystitis. Extended-spectrum beta-lactamase-producing Enterobacteriaceae was found in 25-30% of the samples. Imipenem resistance was found in 70% of Acinetobacter baumannii cases; almost all were resistant to second-generation fluoroquinolones and tetracyclines. The most efficient antibiotic for treating bacterial urinary tract infection was amoxicillin plus clavulanic acid. A. baumannii and Pseudomonas aeruginosa were susceptible to pradofloxacin. Prolonged urine catheterization was linked to lower urinary tract infections by Enterobacter spp., which also correlated with chronic kidney disease.

Chronic kidney disease in a giant panda (Ailuropoda melanoleuca): a case report

BACKGROUND

Chronic kidney disease (CKD) is a common cause of morbidity and mortality in captive wildlife species. However, CKD has been rarely documented in giant pandas.

CASE PRESENTATION

The following report describes a case of an eight-year-old female giant panda showing clinical signs of epistaxis, bloody diarrhea, polyuria, azotemia and anemia. The animal died despite of supportive treatments. Necropsy was performed. Grossly, both kidneys were shrunken and scarred with pallor. Subcutis edema and petechia on the epicardium of the heart were observed. The tissue samples were made into paraffin sections and stained by H.E and special staining including Periodic Acid-Schiff (PAS), von Kossa, Masson's trichrome, Phosphotungstic acid-hematoxylin (PTAH), and Congo red. Histopathology examination revealed severe chronic tubulointerstitial nephritis with marked interstitial fibrosis, glomerulosclerosis, tubular atrophy and calcification in kidneys, and acute necrotizing hemorrhagic myocarditis with calcification in heart. Other lesions included intestinal hemorrhage, hepatic fatty degeneration and necrosis with hemosiderin, and splenic hemosiderin.

CONCLUSIONS

In summary, chronic kidney disease was finally diagnosed based on the association of clinical, gross, and histopathological findings. Heart failure secondary to CKD is the leading cause of death in this giant panda. The potential cause of CKD in this animal is possibly due to long term and uncontrolled hypertension. Blood pressure monitoring is essential in establishing the diagnosis and management of hypertension in giant panda.

Serum amyloid A in cats with renal azotemia

Background and Aim

The concentration of the feline acute-phase protein serum amyloid A (SAA) increases in cats with acute inflammatory diseases. However, it is unclear whether SAA concentration increases in cats with azotemic kidney disease or whether it can aid in differentiating acute kidney injury (AKI) from chronic kidney disease (CKD). Similarly, whether SAA concentration can be used as a prognostic marker is also unclear. Therefore, this study aimed to evaluate the SAA concentrations in cats with azotemic kidney disease and determine whether SAA concentrations can be used to differentiate between AKI, CKD, and "acute on CKD" (AoC). In addition, we evaluated whether SAA concentration could serve as a prognostic parameter. Moreover, we determined the correlations between SAA concentration and temperature; creatinine, urea, and albumin concentrations; leukocyte count; and urine protein/creatinine (UP/C).

Materials and Methods

Forty-eight client-owned azotemic cats (creatinine >250 μmol/L) were included in this prospective study. Cats with pre- and post-renal azotemia were excluded from the study. The causes of azotemia were differentiated into AKI, CKD, and AoC. The SAA concentrations were analyzed through turbidimetric immunoassay at the time of admission. Data were analyzed using the Mann-Whitney U, Kruskal-Wallis, Chi-Square, Fisher's exact, and Spearman correlation tests. p ≤ 0.05 was considered statistically significant.

Results

Serum amyloid A concentration increased in 5/12 cats with AKI, 7/22 cats with CKD, and 9/14 cats with AoC (p = 0.234). The median SAA concentration in cats with AKI, CKD, and AoC whose SAA concentration was ≥5 mg/L was 174 mg/L (10-281 mg/L), 125 mg/L (6-269 mg/L), and 143 mg/L (7-316 mg/L), respectively (p = 0.697), with no significant differences observed between the groups. The median SAA concentration did not differ significantly between survivors (125 mg/L, 10-316 mg/L) and non-survivors (149 mg/L, 6-281 mg/L; p = 0.915) with SAA concentration ≥5 mg/L.

Conclusion

Serum amyloid A concentration increased in 44% of the cats with azotemia. However, it cannot be used to differentiate AKI from CKD or as a prognostic marker. Serum amyloid A concentration was correlated with neutrophil count, albumin concentration, and UP/C, and the presence of comorbidities may influence SAA concentration.

Understanding the barriers to blood pressure assessment in cats

OBJECTIVES

A questionnaire was designed to survey veterinarians and veterinary nurses/technicians on blood pressure (BP) assessment in cats, including ocular examination, encompassing current methodology, indications, uptake and barriers.

METHODS

An online questionnaire was produced and promoted to more than 2000 veterinary professionals, of whom 545 answered all questions and 85 answered most questions.

RESULTS

Of the participants, 572 (90.8%) were based in the UK and almost all (n = 613, 97.3%) had access to a BP monitor. Of those that had a monitor, most (n = 550, 88.4%) participants had access to a Doppler monitor; 367 (59.0%) participants had access to multiparameter monitors; fewer (n = 202, 32.5%) had access to oscillometric BP monitors. Where applicable, Doppler monitors were most commonly chosen for conscious cat measurements (n = 337, 72.2%) due to the greater 'trust' and 'reliability' of these compared with oscillometric machines. Conscious BP measurement typically involved two members of staff (n = 391, 62.9%). Only 156 (29.1%) participants recommended BP assessment at least several times a week in their interactions with cat owners. BP assessment was routinely recommended in cats with ocular target organ damage (n = 365, 87.7%), chronic kidney disease (n = 346, 78.6%), proteinuria (n = 255, 63.0%) and hyperthyroidism (n = 266, 60.9%). Common equipment-related barriers included 'cuff frustration' and difficulties hearing the pulse signal for Doppler users (72.2% and 71.6%, respectively), and oscillometric machines failing to give a reading at least some of the time (52.8%). Situational hypertension concerns affected many (n = 507, 92.0%), as did lack of time to do the procedure (n = 402, 73.0%). Significant owner barriers included difficulties persuading the owner to bring their cat in for BP checks (n = 475, 86.2%) and concerns over costs (n = 445, 80.8%). Most participants had access to a direct ophthalmoscope (n = 527, 96.5%); however, 399 (73.1%) reported that they struggled to interpret ocular findings.

CONCLUSIONS AND RELEVANCE

Significant barriers exist to successful BP assessment in cats. Education and support of clinics should focus on improving confidence with equipment and eye examination.

Retrospective study of canine blood xenotransfusion compared with type-matched feline blood allotransfusion to cats: indications, effectiveness, limitations and adverse effects

OBJECTIVES

Xenotransfusion is the transfusion of blood from one species to another. With varying availability of allogenic feline blood (AFB) and in emergency conditions, circumstances occur when canine blood is transfused to cats. This study aimed to characterise the indications, effectiveness, limitations, and acute and late transfusion-related adverse effects of canine blood xenotransfusion compared with matched AFB to anaemic cats, and their survival and longer-term outcome.

METHODS

This retrospective study (2013-2020) examined cats receiving canine blood xenotransfusions or AFB.

RESULTS

The study included 311 cats (xenotransfusion [X-group], n = 105; allotransfusion [A-group], n = 206). Xenotransfusion was more frequent among cats sustaining haemorrhage than in those with haemolysis (P <0.01) or hypoproliferative anaemia (P <0.001). Financial constraints were the most common reason to elect xenotransfusion (49%). The post-transfusion mean packed cell volume was higher (P <0.001) in the X-group (22%) compared with the A-group (18%), and also higher (P <0.001) at 48-96 h post-transfusion (23% vs 18%, respectively). Transfusion-related adverse effects (TRAEs) were more frequent (P = 0.001) in the X-group (37.1%) compared with the A-group (19.4%), as were delayed haemolytic transfusion reactions (85% vs 42.5%, respectively; P <0.001). Acute transfusion reactions (ATRs) were more frequent (P <0.001) in the A-group (60%) compared with the X-group (20%). TRAEs were unassociated with survival to discharge. The survival to discharge rate of the X-group (55%) was lower (P = 0.007) than in the A-group (73%), while post-discharge survival rates to 30 days of cats surviving to discharge were 90% and 88%, respectively (P = 0.85).

CONCLUSIONS AND RELEVANCE

Canine blood xenotransfusions to cats might save lives in emergency conditions when AFB is unavailable or blood typing is infeasible. The survival to discharge rate of the X-group was lower than that of the A-group. The longer-term survival rate of cats administered xenotransfusions and surviving to discharge from the hospital was good.

Ultrasonographic kidney length-to-abdominal aortic diameter for the diagnosis of feline chronic kidney disease: A preliminary study

Background and Aim

Chronic kidney disease (CKD) is one of the most important diseases in cats. This study aimed to compare the ultrasonographic kidney length-to-abdominal aortic diameter (K/AO) ratio between healthy and CKD cats and investigate the correlation between K/AO and blood results.

Materials and Methods

Fifteen healthy cats and 15 CKD cats were included in this clinically prospective study. All cats were evaluated for radiographic and ultrasonographic K, radiographic K-to-second lumbar length ratio (K/L2), and K/AO, indirect systolic blood pressure and plasma creatinine (Cr), blood urea nitrogen (BUN), and symmetric dimethyl arginine (SDMA).

Results

The radiographic and ultrasonographic kidney lengths of CKD were significantly shorter than those of healthy cats (p < 0.05 and p < 0.05, respectively). The average K/L2 and K/AO were significantly lower in CKD than in healthy cats (p < 0.01 and p < 0.001, respectively). The K/AO had a strong negative correlation with plasma Cr (r = -0.7682, p < 0.0001), BUN (r = -0.6175, p < 0.001), and SDMA (r = -0.589, p < 0.001). However, K/L2 had a moderate negative correlation with plasma Cr (r = -0.5866, p < 0.001), BUN (r = -0.4884, p < 0.01), and SDMA (r = -0.5404, p < 0.01). The optimal cutoff value of K/AO (<10.71) had higher sensitivity and specificity than K/L2 for identifying feline CKD.

Conclusion

Kidney length-to-abdominal aortic diameter could be a better and more promising parameter than the K/L2 ratio for evaluating kidney size in cats with CKD.

Banking on a new understanding: translational opportunities from veterinary biobanks

Current advances in geroscience are due in part to the discovery of biomarkers with high predictive ability in short-lived laboratory animals such as flies and mice. These model species, however, do not always adequately reflect human physiology and disease, highlighting the need for a more comprehensive and relevant model of human aging. Domestic dogs offer a solution to this obstacle, as they share many aspects not only of the physiological and pathological trajectories of their human counterpart, but also of their environment. Furthermore, they age at a considerably faster rate. Studying aging in the companion dog provides an opportunity to better understand the biological and environmental determinants of healthy lifespan in our pets, and to translate those findings to human aging. Biobanking, the systematic collection, processing, storage, and distribution of biological material and associated data has contributed to basic, clinical, and translational research by streamlining the management of high-quality biospecimens for biomarker discovery and validation. In this review, we discuss how veterinary biobanks can support research on aging, particularly when integrated into large-scale longitudinal studies. As an example of this concept, we introduce the Dog Aging Project Biobank.

Bayesian mixed model analysis uncovered 21 risk loci for chronic kidney disease in boxer dogs

Chronic kidney disease (CKD) affects 10% of the human population, with only a small fraction genetically defined. CKD is also common in dogs and has been diagnosed in nearly all breeds, but its genetic basis remains unclear. Here, we performed a Bayesian mixed model genome-wide association analysis for canine CKD in a boxer population of 117 canine cases and 137 controls, and identified 21 genetic regions associated with the disease. At the top markers from each CKD region, the cases carried an average of 20.2 risk alleles, significantly higher than controls (15.6 risk alleles). An ANOVA test showed that the 21 CKD regions together explained 57% of CKD phenotypic variation in the population. Based on whole genome sequencing data of 20 boxers, we identified 5,206 variants in LD with the top 50 BayesR markers. Following comparative analysis with human regulatory data, 17 putative regulatory variants were identified and tested with electrophoretic mobility shift assays. In total four variants, three intronic variants from the MAGI2 and GALNT18 genes, and one variant in an intergenic region on chr28, showed alternative binding ability for the risk and protective alleles in kidney cell lines. Many genes from the 21 CKD regions, RELN, MAGI2, FGFR2 and others, have been implicated in human kidney development or disease. The results from this study provide new information that may enlighten the etiology of CKD in both dogs and humans.

Serum Metabolites Characterization Produced by Cats CKD Affected, at the 1 and 2 Stages, before and after Renal Diet

Utilizing metabolomics, a tool for measuring and characterizing low-molecular-weight substances (LMWs), to identify eventual changes in response to dietary intervention is novel in cats with chronic kidney disease (CKD), a condition characterized by retention of uremic solutes. This study aims to assess the serum metabolomic profile of cats in early stages of CKD and to compare the serum metabolomic of CKD cats after 60 days of a renal diet to evaluate the effect of dietary intervention on these metabolites. Twenty-five domestic cats were included in the study. Fifteen cats with CKD stages 1 (n = 6) and 2 (n = 9) according to the International Renal Interest Society (IRIS) were included in the renal groups, and a control group consisting of 10 cats was included. All animals were enrolled on a maintenance diet for 30 days before the experimental period. The metabolomics analysis was performed by gas chromatography-mass spectrometry (GC-MS). Partial least squares discriminant analysis (PLS-DA) was performed on Metaboanalyst 4.0 software. Forty-three metabolites were identified. Citric acid and monostearin were altered in the CKD2 group when compared to CKD1 and the control group at T0. A total of seven serum metabolites differed after 60 days of the renal diet: glycine, fructose, glutamic acid, arachidonic acid, stearic acid, creatinine, and urea. Changes were seen in the serum metabolomic profile after 60 days of the renal diet, and some of the metabolites that changed in response to the diet have beneficial effects on health. Overall, metabolomics markers have the potential to identify early stages of CKD, providing insights into the possible pathophysiologic processes that contribute to the development and progression of CKD.

Fibrous osteodystrophy due to secondary renal hyperparathyroidism in a senile dog

ABSTRACT Renal hyperparathyroidism stands out among the complications of kidney disease in dogs due to phosphorus retention with a predisposition to hypocalcemia, parathyroid hormone stimulation with mobilization of calcium from the bones, characterizing fibrous osteodystrophy, unusual in the elderly. The objective was to report it in 12-year-old Labrador with polyuria, polydipsia, and emesis for five months due to maxillary and mandibular volume increase, followed by loosely fixed teeth, and facial deformity. Blood tests showed anemia, thrombocytosis, azotemia, hypoalbuminemia and hyperphosphatemia and urinalysis showed low density, glycosuria, proteinuria, and moderate caudate and transitional epithelial cells. Oral x-rays showed loss of dental bone support and decreased bone radiopacity. Chest radiographs showed decreased density in the ribs and costochondral junction; on the other hand, organs of the cardiorespiratory system showed no changes. The electrocardiogram and echocardiogram did not show impairment. Abdominal ultrasound revealed kidneys with asymmetry, increased echogenicity of the cortical and poorly preserved cortico-medullary definition. Oral histopathology showed intense fibroplasia associated with bone reabsorption. Support therapy was instituted, but the patient died ten days after consultation. Thus, although uncommon in the elderly, fibrous osteodystrophy should be investigated in dogs with advanced-stage chronic kidney disease and, even with conservative therapies, the prognosis is unfavorable.

Serum uromodulin in dogs with chronic kidney disease

BACKGROUND

Serum uromodulin concentration has been described as a novel biomarker of chronic kidney disease (CKD) in humans but not dogs.

OBJECTIVE

To evaluate the serum uromodulin concentration in dogs with CKD and assess its diagnostic performance in distinguishing dogs with CKD from healthy dogs.

ANIMALS

Forty-nine dogs with CKD (International Renal Interest Society [IRIS] Stage 1, n = 23; Stage 2, n = 20; Stage 3-4, n = 6) and 25 healthy controls.

METHODS

Prospective, observational study. Serum uromodulin concentration was measured using a canine-specific enzyme-linked immunosorbent assay (ELISA), and its correlation with conventional renal markers was analyzed.

RESULTS

Serum uromodulin concentrations were significantly lower in the CKD group than in the control group (P < .001), but no significant difference was observed among stages of CKD. A negative correlation was observed between serum uromodulin concentration and conventional renal markers (blood urea nitrogen concentration, r = -.60, P < .0001; serum creatinine concentration, r = -.46, P < .0001; serum symmetric dimethylarginine concentration [SDMA], r = -.65, P < .0001). In receiver operating characteristic analysis, the area under the curve (AUC) of uromodulin (AUC, 0.97; 95% confidence interval [CI], 0.94-1.00) was higher than that of SDMA (AUC, 0.87; 95% CI, 0.79-0.95) for CKD diagnosis (P = .01). The AUC of uromodulin (AUC, 0.95; 95% CI, 0.89-1.00) also was higher than that of SDMA (AUC, 0.72; 95% CI, 0.58-0.87) in distinguishing dogs with Stage 1 CKD from controls (P = .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum uromodulin concentration is decreased in dogs with CKD. Thus, serum uromodulin may be a valuable diagnostic marker for CKD in dogs, particularly in identifying early-stage CKD.

Weight measurements result in improved accuracy and precision in preparation of cooked homemade diets for dogs

OBJECTIVE

Accurate measurement of ingredients for cooked homemade diets helps ensure diets are complete and balanced. Studies have demonstrated measuring dry dog food with measuring cups results in significant inaccuracy. Therefore, measuring ingredients by volume when preparing these diets may be inaccurate. The purpose was to determine the accuracy of preparing cooked homemade diets by measuring ingredients by volume (measuring cups and spoons) or weight (digital gram scale with a syringe for measuring oil only).

SAMPLES

42 diet samples prepared by 21 participants.

PROCEDURES

21 participants were instructed on homemade diet preparation based on weight or volume measurement methods. Diet samples underwent proximate analysis and mineral analysis. Data, expressed on a dry matter basis (DMB) and an energy density basis (EDB), from both groups were compared to the anticipated nutrient profile to determine which method resulted in more accuracy. Data from individual samples within each group were compared to each other to determine the precision of both methods.

RESULTS

Weight measurements were more precise for crude protein, crude fat, nitrogen-free extract, and potassium (DMB and EDB) and more accurate for ash (DMB and EDB) and iron (EDB). Comparatively, volume measurements were more precise for ash (DMB) and more accurate for iron (DMB).

CLINICAL RELEVANCE

Findings suggest weight measurements should be utilized to prepare cooked homemade diets for dogs to promote precision and accuracy.

C-reactive protein concentrations are higher in dogs with stage IV chronic kidney disease treated with intermittent hemodialysis

In chronic kidney disease dogs, the inflammatory process increases C-reactive protein concentrations. This study aimed to determine C-reactive protein serum concentrations in stage IV chronic kidney disease dogs treated with intermittent hemodialysis. A prospective cohort study was conducted with 23 dogs allocated into three groups: control group (CG, n = 7), intermittent hemodialysis group (IHG, n = 8) and clinical treatment group (CTG, n = 8), both comprised of stage IV chronic kidney disease dogs. One blood sample from CG (initial evaluation) and two samples from IHG and CTG (first- and last-moment) were obtained to determine C-reactive protein concentration, total leukocytes, platelets, erythrocytes, total plasma protein, serum albumin, urea, creatinine, and phosphorus. C-reactive protein was higher in IHG compared to CG in the first- and last-moments (p <0.001) and compared to CTG in the first-moment (p = 0.0406). C-reactive protein presented moderate positive correlation with leukocytes (r = 0.5479; p = 0.01), and moderate negative correlation with albumin (r = - 0.5974; p = 0.006) and red blood cells (r = - 0.5878, p = 0.01). A high correlation coefficient was observed in the tests' evaluation (CI = 0.59-0.78; r = 0.70; P<0.0001). In conclusion, both assays used in this study to measure C-reactive protein have provided safe and reliable quantification of the results. Additionally, despite IHG dogs presented an active inflammatory profile, intermittent hemodialysis has proven to be beneficial, leading to a clinical improvement in life quality of patients, and thus being recommended for stage IV CKD dogs when performed by trained professionals.

An early prediction model for canine chronic kidney disease based on routine clinical laboratory tests

The aim of this study was to derive a model to predict the risk of dogs developing chronic kidney disease (CKD) using data from electronic health records (EHR) collected during routine veterinary practice. Data from 57,402 dogs were included in the study. Two thirds of the EHRs were used to build the model, which included feature selection and identification of the optimal neural network type and architecture. The remaining unseen EHRs were used to evaluate model performance. The final model was a recurrent neural network with 6 features (creatinine, blood urea nitrogen, urine specific gravity, urine protein, weight, age). Identifying CKD at the time of diagnosis, the model displayed a sensitivity of 91.4% and a specificity of 97.2%. When predicting future risk of CKD, model sensitivity was 68.8% at 1 year, and 44.8% 2 years before diagnosis. Positive predictive value (PPV) varied between 15 and 23% and was influenced by the age of the patient, while the negative predictive value remained above 99% under all tested conditions. While the modest PPV limits its use as a stand-alone diagnostic screening tool, high specificity and NPV make the model particularly effective at identifying patients that will not go on to develop CKD.

Does intravenous contrast medium administration result in altered renal biomarkers? A study in clinically stable cats with and without azotemia

OBJECTIVES

The aim of this study was to determine the prevalence of post-contrast acute kidney injury or comparable side effects on kidney function in cats receiving the non-ionic, iodinated agent ioversol and/or paramagnetic agent gadoteric acid.

METHODS

Fifty-two animals were divided into four groups on the basis of contrast medium administration for imaging: ioversol (n = 27), gadoteric acid (n = 12), dual contrast media (n = 4) or control, which received an infusion of isotone intravenous fluids only during anaesthesia (n = 9). Blood and urine samples were obtained three times after contrast administration and compared with values obtained prior to administration of the contrast medium. Creatinine (<1.60 mg/dl), symmetric dimethylarginine (SDMA; ⩽14 μg/dl), urine protein:creatinine ratio (UPC; <0.2) and critical differences for creatinine (<0.3 mg/dl) and SDMA (<5.98 μg/dl) were measured.

RESULTS

No significant short-term effects on mean creatinine, SDMA and UPC measurements were seen. Borderline proteinuria (UPC, 0.2-0.4) was detected in 11.4% of cases after contrast media administration. A UPC of more than 0.2 in five cases indicated that contrast media may affect kidney function, leading to (transient) proteinuria.

CONCLUSIONS AND RELEVANCE

This study found no side effect on renal function following the administration of ioversol or gadoteric acid, provided patients were adequately hydrated. However, the clinical relevance of proteinuria in some cats needs to be evaluated in future studies.

Serum concentrations of leptin and adiponectin in dogs with chronic kidney disease

BACKGROUND

An imbalance in adipokines is associated with the progression of chronic kidney disease (CKD) in humans. However, alterations in adipokines in dogs with CKD remain unclear.

OBJECTIVES

To examine whether adipokine concentrations in serum differ between healthy dogs and dogs with CKD and to determine the correlation between serum adipokine concentrations and CKD severity in dogs.

ANIMALS

Twenty dogs with CKD and 10 healthy dogs.

METHODS

In this cross-sectional study, serum concentrations of leptin, adiponectin, interleukin (IL)-6, IL-10, IL-18, and tumor necrosis factor (TNF)-α were measured in healthy dogs and dogs with CKD, which were classified according to the International Renal Interest Society guidelines.

RESULTS

Serum leptin concentrations were positively correlated with systolic arterial blood pressure (r = .41), creatinine concentrations (r = .39), and symmetric dimethylarginine concentrations (r = .73). Serum adiponectin concentrations (median [range]) in CKD dogs with borderline or non-proteinuric (20.25 [14.9-45.8] ng/mL) were significantly higher than those in proteinuric CKD dogs (13.95 [6.4-22.1] ng/mL; P = .01). Serum IL-6 (median [range]; 43.27 [24.30-537.30] vs 25.63 [6.83-61.03] pg/mL; P = .02), IL-18 (median [range]; 25.98 [11.52-280.55] vs 10.77 [3.53-38.45] pg/mL; P = .01), and TNF-α (median [range]) concentrations (11.44 [8.54-38.45] vs 6.105 [3.97-30.68] pg/mL; P = .02) were significantly different between proteinuric and borderline or non-proteinuric CKD dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

leptin and adiponectin concentrations in serum might be associated with severity of CKD and proteinuria in dogs with CKD, respectively.

Nephrin and podocin mRNA detection in urine sediment of dogs with chronic kidney disease: preliminary observations

Introduction

Dogs with chronic kidney disease (CKD) may have alterations in the glomerular filtration barrier, including podocyte loss. Detection of podocyte mRNA in urine could be useful for assessing podocyturia in dogs with kidney disease. The objective of this study was to evaluate the presence of nephrin mRNA (NPHS1) and podocin mRNA (NPHS2) in urine sediments of dogs with naturally occurring CKD and healthy dogs.

Material and Methods

Twenty-four dogs, 14 with CKD and 10 as healthy controls, underwent clinical evaluation. The dogs with CKD were divided into two groups, according to the International Renal Interest Society criteria: stage 1 or 2 CKD (n = 5) and stage 3 or 4 CKD (n = 9). Urine was collected by catheterisation or free catch and RNA isolation from the urine sediments was optimised using glycogen as a co-precipitant. Detection of NPHS1 and NPHS2 in the sediment samples was performed using quantitative real-time PCR.

Results

Both types of mRNA were detected in samples from all groups, but the percentages of detection were higher in the group of dogs with stage 1 or 2 CKD and lower in the group of dogs with stage 3 or 4 disease.

Conclusion

Physiological podocyturia was observed in healthy dogs, and the results suggest differential podocyturia in dogs with CKD, according to the stage of the disease, i.e. an increase in podocyturia in dogs at stage 1 or 2 and a reduction in podocyturia in dogs at stage 3 or 4.

[Role of systemic infections in canine kidney diseases]

Kidney diseases represent a common problem as well as a frequent cause of death in dogs. Infectious agents may be responsible for glomerulopathies and acute kidney injuries. Many infections commonly associated with the development of immune complex glomerulonephritis in central and southern Europe are important as travel-associated diseases in Germany. These include leishmaniosis, dirofilariosis, and ehrlichiosis. Rarely, anaplasmosis, hepatozoonosis, Lyme disease as well as babesiosis caused by small Babesia spp. are detected as cause of canine immune complex glomerulonephritis in Germany. Leptospirosis, canine infectious hepatitis, and babesiosis caused by large Babesia spp. may be responsible for the development of acute kidney injuries associated with tubulointerstitial nephritis. Therefore, further diagnostics aiming at identifying potentially causative infectious agents in dogs with renal disease is important for both prognosis and therapy of the patient.

MicroRNAs: Potential biomarkers for reproduction, diagnosis, prognosis, and therapeutic in domestic animals

MicroRNA (miRNAs) are small non-coding RNA molecules involved in a wide range of biological processes through the post-transcriptional regulation of gene expression. Most studies evaluated microRNA expression in human, and despite fewer studies in veterinary medicine, this topic is one of the most exciting areas of modern veterinary medicine. miRNAs showed to be part of the pathogenesis of diseases and reproduction physiology in animals, making them biomarkers candidates. This review provides an overview of the current knowledge regarding miRNAs' role in reproduction and animal diseases, diagnostic and therapy.

Evaluation of Serum and Urine Amino Acids in Dogs with Chronic Kidney Disease and Healthy Dogs Fed a Renal Diet

This observational study aimed to evaluate serum and urinary amino acid (AA) concentrations in healthy dogs and dogs with chronic kidney disease (CKD) fed a commercial therapeutic renal diet with reduced protein and phosphorus levels. Ten dogs with CKD stages 3 or 4 composed the study group and received the renal diet for 180 days (RG T180). A control group (CG T30) composed of seven healthy dogs was fed a renal diet for 30 days. When comparing serum AA between RG T180 and CG T30, histidine, isoleucine, leucine, lysine, phenylalanine, tryptophan, cysteine, citrulline, ornithine, taurine, branched-chain amino acids (BCAA), and total essential amino acids (EAA) were higher in RG T180. Meanwhile, arginine, asparagine, aspartate, glutamine, serine, and tyrosine were higher in CG T30. Serum phenylalanine, tryptophan, and hydroxyproline were higher in RG T0 (dogs with CKD before consuming a renal diet) when compared to RG T180. In addition, the serum ratios of arginine/citrulline, tyrosine/phenylalanine, and serine/glycine were higher in CG T30 than in RG T180. Concerning urinary AA concentrations in CKD dogs, isoleucine, phenylalanine, tryptophan, aspartate, cysteine, and BCAA were higher in RG T180. In urine, the total EAA/total non-essential AA ratio in RG T180 was higher than in CG T30 as well as tyrosine/phenylalanine ratio higher in CG T30. In conclusion, the combination of renal diet and conservative treatment over 6 months in dogs with CKD stages 3 or 4 affected the AAs metabolism when compared to healthy adult dogs.

The Source Matters-Effects of High Phosphate Intake from Eight Different Sources in Dogs

Elevated serum phosphate concentrations are an established risk factor for cardiovascular disease and mortality in chronic kidney disease in various species. Independent associations of other parameters of phosphorus metabolism, such as phosphorus intake from different sources and serum concentrations of phosphorus, as well as parameters involved in the regulation, such as parathyroid hormone (PTH) or markers of bone turnover, have been studied in less detail. Therefore, the serum kinetics of phosphate, PTH, and the bone resorption marker bone-specific alkaline phosphatase (BAP) were investigated after 18 days of feeding a control diet and diets supplemented with eight different organic and inorganic phosphate sources aiming at 1.8% phosphorus per dry matter and calcium to phosphorus ratio between 1.3 and 1.7 to 1. Eight healthy beagle dogs (f/m, 2-4 years, 12.9 ± 1.4 kg body weight) were available for the trial. Highly significant differences in the serum kinetics of phosphorus, PTH, and BAP with the highest postprandial levels after feeding highly water-soluble sodium and potassium phosphates were found. We conclude that the use of certain inorganic phosphates in pet food is potentially harmful and should be restricted.

Establishment of an RI for the urine ammonia-to-creatinine ratio in dogs

Background

Ammonia is produced and excreted by the kidney, contributing to systemic acid‐base homeostasis through the production of bicarbonate. Disorders of acid‐base balance can lead to many clinical problems and measuring ammonia excretion helps in determining if the kidneys are responding to acid‐base challenges appropriately. Reference intervals are integral to clinical decision‐making, and there is no current RI for the urine ammonia‐to‐creatinine ratio (UACR) in dogs.

Objective

This study aimed to generate an RI for the UACR in healthy adult dogs.

Methods

The study used adult, client‐owned dogs that were presented to the University of Florida Primary Care and Dentistry service (n = 60). Physical examinations were performed and serum chemistry and urinalysis samples were obtained. Urine ammonia and creatinine concentrations were determined. Dogs were excluded if there were significant abnormalities in either their urinalysis or serum chemistry results. The RI for the UACR was calculated according to the recommendation of the American Society for Veterinary Clinical Pathology. Data were evaluated for correlation with serum bicarbonate, weight, age, and sex.

Results

The RIs for the UACR were 0.16‐23.69 with 90% confidence intervals for the lower and upper limits of (0.13‐1.17) and (20.50‐23.75), respectively. No significant impact of age, sex, or weight was found. There was no discernable relationship between serum bicarbonate and UACR.

Conclusions

Establishing an RI for UACR in healthy adult dogs will allow for further studies to determine if alterations are observed during specific disease states.

Healthy and Chronic Kidney Disease (CKD) Dogs Have Differences in Serum Metabolomics and Renal Diet May Have Slowed Disease Progression

Chronic kidney disease (CKD) is highly prevalent in dogs, and metabolomics investigation has been recently introduced for a better understanding of the role of diet in CKD. This study aimed to compare the serum metabolomic profile of healthy dogs (CG) and dogs with CKD (CKD-T0 and CKD-T6) to evaluate whether the diet would affect metabolites. Six dogs (5 females; 1 male; 7.47 ± 2.31 years old) with CKD stage 3 or 4 (IRIS) were included. CG consisted of 10 healthy female dogs (5.89 ± 2.57 years old) fed a maintenance diet. Serum metabolites were analyzed by ¹H nuclear magnetic resonance (¹H NMR) spectra. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were performed to assess differences in metabolomic profiles between groups and before (CKD-T0) and after renal diet (CKD-T6). Data analysis was performed on SIMCA-P software. Dogs with CKD showed an altered metabolic profile with increased urea, creatinine, creatine, citrate, and lipids. Lactate, branched-chain amino acids (BCAAs), and glutamine were decreased in the CKD group. However, after 6 months of diet, the metabolite profiles of CKD-T0 and CKD-T6 were similar. Metabolomics profile may be useful to evaluate and recognize metabolic dysfunction and progression of CKD, and the diet may have helped maintain and retard the progression of CKD.