Chronic kidney disease in dogs in UK veterinary practices: prevalence, risk factors, and survival

Longitudinal Study of Renal Health Screening in Apparently Healthy Aging Dogs

BACKGROUND

Combined measurement of functional, glomerular, and tubular markers in aging dogs is essential to detect early renal disease.

OBJECTIVES

Prospective longitudinal study to describe renal function and assess which biomarkers are associated with the development of early renal disease or death.

ANIMALS

One hundred and twenty-two apparently healthy senior and geriatric dogs.

METHODS

Prospective longitudinal study. Renal function was evaluated at baseline (T0) and every 6-12 months over 2 years, using systolic blood pressure measurements (SBP) and validated serum (creatinine, symmetric dimethylarginine, cystatin C [sCysC]), and urinary (specific gravity [USG], protein:creatinine [UPC], albumin:creatinine, retinol-binding protein:creatinine [uRBPcr]) biomarkers. Glomerular filtration rate (GFR) was measured in a subgroup. Survival models were used to assess the predictive value of measured biomarkers at baseline for the onset of azotemic chronic kidney disease (CKD) or death, respectively.

RESULTS

A total of 122 dogs were included; follow-up was available in 106 (T12) and 92 (T24); and GFR was estimated in 18 (T0), 11 (T12), and 10 (T24) dogs. Throughout the study, 15/122 (12%) dogs showed evidence of non-azotemic CKD, and in 11/106 (10%) dogs, azotemic CKD developed. Proteinuria was not associated with azotemic CKD, in contrast to muscle condition score, functional markers, and uRBPcr. Death was weakly associated with USG, UPC, and sCysC.

CONCLUSIONS AND CLINICAL IMPORTANCE

Over a 2-year period, 20% (26/122) of older dogs developed CKD, mostly persistent renal proteinuria (15/122). Muscle wasting and functional markers combined with uRBPcr had the best predictive value for the onset of azotemic CKD in these older, previously apparently healthy dogs.

Urinary Cystatin C, Glucose, Urea, and Electrolytes in Dogs at Various Stages of Chronic Kidney Disease

BACKGROUND

There is limited knowledge of urine analytes in different stages of chronic kidney disease (CKD) in dogs.

OBJECTIVES

To study markers in urine and fractional excretion (FE) of markers in dogs of different stages of CKD and a healthy control group (C).

ANIMALS

Fifty dogs in various stages of CKD and a control group of 30 healthy dogs.

METHODS

In this cross-sectional observational study, dogs presenting to a referral hospital and given a diagnosis of CKD using standard methods, and healthy dogs, were included. Urinary cystatin C (uCysC), glucose (uGlu), protein (uProt), creatinine (uCr), urea (uUrea), sodium (uNa), potassium (uK), chloride (uCl), calcium (uCa), and phosphate (uP) were measured with an automated chemistry analyzer. Included analytes were normalized to uCr, FE of electrolytes and urea was calculated, and results compared among groups.

RESULTS

Age, bodyweight, and sex were not different among groups. Urinary CysC/uCr and FE of electrolytes increased with IRIS stage. Median (IQR) for uCysC/uCr was 0.08 (0.04-0.25) 10-3 in dogs with CKD stage 1 and 0.03 (0.02-0.045) 10-3 in control dogs (p = 0.0002).

CONCLUSION AND CLINICAL IMPORTANCE

Urinary CysC might be a potential marker of early CKD, preferably as part of a panel of urinary markers. FE of electrolytes seemed to depend on the serum creatinine level in dogs with azotemic CKD.

Analysis of survival among biopsy-determined categories of kidney disease in dogs

BACKGROUND

There are many causes of kidney disease in dogs. The association of the diagnostic category with survival is unknown.

OBJECTIVE

Determine survival outcomes for biopsy-determined diagnostic categories of kidney disease in dogs.

ANIMALS

Six hundred forty-nine dogs were biopsied for evaluation of kidney disease.

METHODS

Retrospective study. Survival information was obtained for dogs whose kidney biopsy was submitted to the International Veterinary Renal Pathology Service between 2008 and 2018. Signalment, serum creatinine (sCr), urine protein : creatinine ratio (UPCR), and serum albumin (sAlb) were reported at the time of biopsy. Cox proportional hazards analysis was performed for the 14 categories with >10 cases having follow-up to determine hazard ratios (HR), using focal segmental glomerulosclerosis (FSGS) as baseline.

RESULTS

The median survival time (MST) for all dogs with follow-up (n = 649) was 608 days (interquartile range [IQR]: 109-1475 days). The most follow-up was obtained for FSGS (n = 138, MST 536 days). Dogs with renal amyloidosis (n = 80) had the shortest survival (MST 76 days, IQR 8-299 days) and, in the multivariate analysis including age, sCr, sAlb, and UPCR, an increased risk of death (HR 1.79 [95% CI: 1.22-2.65], P < .01). Dogs with podocytopathy, membranous glomerulonephritis (MGN), mixed MGN, membranoproliferative GN (MPGN), and mixed MPGN had decreased risk of death. Regardless of category, increasing age, sCr, and UPCR and decreased sAlb were associated with a greater risk of death.

CONCLUSIONS

The diagnostic category is associated with survival in dogs with kidney disease. Survival of individual dogs within each category was highly variable.

Effects of Paricalcitol on Renal Secondary Hyperparathyroidism and Proteinuria in Dogs With Chronic Kidney Disease

BACKGROUND

Renal secondary hyperparathyroidism (RHPT) is an inevitable consequence of chronic kidney disease (CKD). Paricalcitol might safely attenuate RHPT and proteinuria.

HYPOTHESIS/OBJECTIVE

Paricalcitol decreases parathyroid hormone (PTH) and proteinuria in dogs with CKD.

ANIMALS

Thirteen dogs with naturally acquired CKD.

METHODS

Placebo-controlled clinical trial. Dogs were randomly allocated to receive a placebo or paricalcitol (14 ng/kg/day) in a crossover design of 2, 12-week arms. Dogs were evaluated every 3 weeks. Associations between treatment, visit, and the outcome variables were assessed using generalized estimating equations.

RESULTS

PTH decreased by 22% (95% CI, 7%-35%, p = 0.006) in the paricalcitol-treated dogs and increased by 18% (95% CI, 2%-37%, p = 0.022) in the placebo-treated dogs with each visit. FGF-23 at 12 weeks increased compared with baseline in the paricalcitol-treated (mean 6941 pg/mL, 95% CI, 1781-20 057 vs. 489 pg/mL, 95% CI, 188-1272, p < 0.001, respectively), but not in the placebo-treated dogs (696 pg/mL, 95% CI, 316-1531 vs. 955 pg/mL, 95% CI, 308-2963, p = 0.529). Urine protein-to-creatinine ratio at 12 weeks increased compared with baseline in the placebo-treated (0.8, 95% CI, 0.3-1.3 vs. 0.5, 95% CI, 0.2-0.9, p = 0.04, respectively), but not in the paricalcitol-treated dogs (0.6, 95% CI, 0.3-0.9 vs. 1.0, 95% CI, 0.1-1.8, p = 0.35). Ionized calcium was unchanged between baseline and 12 weeks in the paricalcitol- and placebo-treated groups (1.3 mmol/L, 95% CI, 1.29-1.35 and 1.34, 95% CI, 1.27-1.40 vs. 1.30, 95% CI, 1.25-1.35, p = 0.12 and 1.28, 95% CI, 1.24-1.32, p = 0.034, respectively). However, 7/13 dogs developed mild hypercalcemia. Adverse effects were not reported by the owners.

CONCLUSION AND CLINICAL IMPORTANCE

Paricalcitol attenuated RHPT and stabilized renal proteinuria in dogs with CKD.

The renin-angiotensin-aldosterone system in kidney diseases of cats and dogs

The renin-angiotensin-aldosterone system (RAAS) has a well-established key pathophysiologic role in kidney diseases, and pharmacotherapy targeting this system is a mainstay of treatment of affected human beings, cats, and dogs. Several studies have evaluated the circulating RAAS in animals with spontaneous or experimentally induced kidney diseases. Evidence supporting the activation of this system has been demonstrated in some - but not all - studies and individuals, and the interindividual variability in circulating RAAS markers is high. Advances over the last few decades have expanded our understanding of the system, which now includes the existence of a counterbalancing "alternative" RAAS and tissular renin-angiotensin systems (RASs), the latter regulated independently of the circulating endocrine RAAS. The local RAS in the kidney, termed the intrarenal RAS, is currently recognized as an important regulator of kidney function and mediator of kidney disease. In general, information on the intrarenal RAS is lacking in cats and dogs with kidney diseases; however, existing limited data suggest its activation. Despite the inconsistent evidence for circulating RAAS activation in chronic kidney diseases, RAAS inhibitors have proven effective for the treatment of its common comorbidities, systemic arterial hypertension and renal proteinuria, in both cats and dogs. Further research of the circulating RAAS, the intrarenal RAS, and the interplay between these systems in the context of kidney diseases in companion animals might contribute to the development or refinement of future treatment strategies.

Serum symmetric dimethylarginine concentrations in enalapril- or telmisartan-treated dogs with proteinuric chronic kidney disease

Introduction

Renin-angiotensin-aldosterone system inhibition (RAASi) reduces intraglomerular pressure and is a standard therapy for dogs with proteinuric chronic kidney disease (CKD). RAASi can acutely decrease glomerular filtration rate (GFR); however, its effects on the marker of GFR serum symmetric dimethylarginine (SDMA) concentration in dogs have not been specifically evaluated. The objective of this study was to evaluate changes, relative to pretreatment values, in serum SDMA concentrations in dogs with proteinuric CKD receiving RAASi therapy.

Methods

This retrospective study used banked samples from 29 dogs with proteinuric CKD treated with enalapril (0.5 mg/kg PO q12h; n = 16) or telmisartan (1 mg/kg PO q24h; n = 13) alone (n = 22) or in combination with amlodipine if severely hypertensive (n = 7). Serum SDMA, creatinine, and urea nitrogen (SUN) concentrations were measured before and 7 and 30 days after starting RAASi. Percentage and absolute changes in these biomarkers were calculated for each dog and time point. A linear mixed model was used to test whether changes significantly differed from zero (α < 0.05).

Results

Overall, mean ± SEM Day 7 and 30 percentage change in SDMA were  - 4.8 ± 3.6% and  - 3.2 ± 3.4%, respectively; in creatinine were 7.4 ± 3.3% and 3.0 ± 3.1%, respectively; and in SUN were 22.1 ± 6.8% and 16.7 ± 6.2%, respectively. Mean changes varied according to whether all dogs, those on RAASi alone, or those co-treated with amlodipine were evaluated. In dogs receiving RAASi alone, at day 7, there were significant mean percentual increases in creatinine (9%; p = 0.023) and SUN (23%; p = 0.005), but SDMA was unchanged. In dogs co-treated with amlodipine, a significant absolute decrease in mean SDMA (-2.29 μg/dL; p = 0.026) occurred at days 7 and 30, while mean creatinine was unchanged and mean SUN increased.

Discussion

Proteinuric dogs receiving RAASi had low-magnitude changes in serum SDMA and creatinine, and moderate-magnitude changes in SUN concentrations. The direction of change in SDMA did not consistently match that of creatinine and SUN.

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.

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.

Occurrence of bacteremia, bacteriuria and bacteriuria-related bacteremia in dogs and cats with chronic kidney disease. A pilot study

In human medicine, major infections are the most significant and critical non-cardiovascular complications in patients affected by chronic kidney disease (CKD), with bacteriuria being the primary source of bloodstream infections and its evolution toward sepsis. The availability of data on prevalence of bacteremia and its association with bacteriuria in dogs and cats with CKD is limited. The aim of this observational cross-sectional study was to determine the occurrence of bacteremia, bacteriuria, and bacteriuria-related bacteremia in dogs and cats affected by CKD. Client-owned dogs and cats with a documented history of CKD undergoing disease follow-up were enrolled. Each included animal underwent a comprehensive physical examination, clinico-pathological and microbiological analyses of blood and urine, along with molecular detection of the 16S rRNA bacterial gene in blood. Aseptically collected blood and urine were obtained through jugular venipuncture and cystocentesis, respectively. After collection, blood and urine samples underwent bacteriological culture within one hour. In the population enrolled, 2/47 dogs and 1/41 cats presented bacteriemia. Moreover, 8/47 dogs and 6/41 cats presented a positive urine culture. Additionally, in one out of the 47 dogs, the same pathogen was identified from blood and urine samples, with a final diagnosis of urosepsis. No instances of bacteriuria-related bacteriemia were observed in the cat population. In conclusion, this study shows a low prevalence of bacteremia and confirms a high prevalence of bacteriuria in companion animals affected by CKD. Moreover, a low prevalence of bacteriuria-related bacteremia was also found.

Pirfenidone inhibits TGF-β1-induced fibrosis via downregulation of Smad and ERK pathway in MDCK cells

The prevalence of chronic kidney disease (CKD) in dogs increases with age, and renal fibrosis is an important pathophysiological mechanism in this process. However, only a few drugs that can effectively inhibit fibrosis in the kidneys of dogs are currently available. In this study, we aimed to determine whether pirfenidone, a drug that has shown antifibrotic effects in various clinical studies, also exerts antifibrotic effects on canine renal tubular epithelial cells, Madin-Darby canine kidney cells (MDCK). To this end, we treated MDCK cells with various concentrations of pirfenidone, followed by transforming growth factor-beta1 (TGF-β1) to stimulate fibrotic conditions. A cell viability assay was performed to determine the effect of pirfenidone on cell survival. Fibrosis-related markers and TGF-β1 fibrotic pathway-related markers were assessed using qPCR, Western blot analysis and immunocytochemistry. A one-way analysis of variance (ANOVA) was performed, followed by Tukey's post-hoc test for multiple comparisons. Pirfenidone treatment significantly reduced the expression of profibrotic markers such as α-smooth muscle actin, fibronectin, and collagen. Additionally, it upregulated the expression of E-cadherin, an epithelial marker. Furthermore, pirfenidone effectively inhibited the phosphorylation of key factors involved in the TGF-β1 signaling pathway, including Smad2/3 and ERK1/2. These results demonstrate that pirfenidone suppresses TGF-β1-induced fibrosis in MDCK cells by attenuating epithelial-mesenchymal transition and the relevant signaling pathways.

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.

Insights into the gut-kidney axis and implications for chronic kidney disease management in cats and dogs

Chronic kidney disease (CKD) in cats and dogs presents significant clinical challenges, with emerging research highlighting the pivotal role of the gut-kidney axis in its pathogenesis and management. Gut dysbiosis, characterized by alterations in the gut microbiome composition and function, contributes to microbial dysmetabolism of key nutrients causing uremic toxin accumulation and disruptions in amino acid, bile acid and fatty acid profiles. These disturbances in turn exacerbate renal dysfunction and systemic inflammation. Recent research in veterinary medicine, particularly in cats, supports the gut microbiome and microbial-derived metabolites as novel therapeutic targets. Potential therapeutic strategies targeting the gut microbiome and microbial dysmetabolism, including dietary management, probiotics, adsorbents, and addressing constipation, offer promising avenues for intervention to restore metabolic balance and preserve renal function. This review highlights the microbial influence on renal health and focuses on potential therapeutic strategies available to veterinarians to optimize the management of CKD in cats and dogs.

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.

Investigation of symmetric dimethylarginine as a serologic marker for kidney function in striped skunks (Mephitis mephitis)

IMPORTANCE

Kidney disease is prevalent among veterinary species, including zoo animals; however, investigations into this condition in striped skunks (Mephitis mephitis) are scarce. Diagnostic tools for kidney diseases in this species also remain limited.

OBJECTIVE

This study aimed to assess the utility of symmetric dimethylarginine as a biomarker for kidney disease in captive striped skunks in Korea.

METHODS

This retrospective study analysed 11 striped skunks housed at the Everland Zoo between 2017 and 2021. Blood samples were collected during health checks. Kidney function was assessed through blood analysis and diagnostic ultrasound, with necropsies conducted on deceased animals. Symmetric dimethylarginine levels were measured in 27 plasma samples collected from 11 skunks.

RESULTS

Over the study period, seven skunks were diagnosed with kidney disease. Analysis of 27 blood samples revealed a concurrent increase in SDMA levels with concentrations of blood urea nitrogen and blood creatinine. In 3 of the 7 skunks with kidney disease, symmetric dimethylarginine exceeded 14 µg/dL prior to the elevation of blood urea nitrogen and blood creatinine above the upper reference limit.

CONCLUSIONS AND RELEVANCE

To our knowledge, this is the first study investigating symmetric dimethylarginine in captive striped skunks in Korea. Our findings suggest that symmetric dimethylarginine may serve as an early and consistent biomarker for renal dysfunction in striped skunks. Further studies with larger clinical sample size from striped skunks are needed to validate the clinical utility of blood symmetric dimethylarginine concentration.

Assessment of pharmacologically induced changes in canine kidney function by multiparametric magnetic resonance imaging and contrast enhanced ultrasound

Introduction

Dynamic contrast-enhanced (DCE) MRI and arterial spin labeling (ASL) MRI enable non-invasive measurement of renal blood flow (RBF), whereas blood oxygenation level-dependent (BOLD) MRI enables non-invasive measurement of the apparent relaxation rate (R2*), an indicator of oxygenation. This study was conducted to evaluate the potential role of these MRI modalities in assessing RBF and oxygenation in dogs. The correlation between contrast-enhanced ultrasound (CEUS) and the MRI modalities was examined and also the ability of the MRI modalities to detect pharmacologically induced changes.

Methods

RBF, using CEUS, ASL- and DCE-MRI, as well as renal oxygenation, using BOLD-MRI of eight adult beagles were assessed at two time-points, 2–3 weeks apart. During each time point, the anesthetized dogs received either a control (0.9% sodium chloride) or a dopamine treatment. For each time point, measurements were carried out over 2 days. An MRI scan at 3 T was performed on day one, followed by CEUS on day two.

Results

Using the model-free model with caudal placement of the arterial input function (AIF) region of interest (ROI) in the aorta, the DCE results showed a significant correlation with ASL measured RBF and detected significant changes in blood flow during dopamine infusion. Additionally, R2* negatively correlated with ASL measured RBF at the cortex and medulla, as well as with medullary wash-in rate (WiR) and peak intensity (PI). ASL measured RBF, in its turn, showed a positive correlation with cortical WiR, PI, area under the curve (AUC) and fall time (FT), and with medullary WiR and PI, but a negative correlation with medullary rise time (RT). During dopamine infusion, BOLD-MRI observed a significant decrease in R2* at the medulla and entire kidney, while ASL-MRI demonstrated a significant increase in RBF at the cortex, medulla and the entire kidney.

Conclusion

ASL- and BOLD-MRI can measure pharmacologically induced changes in renal blood flow and renal oxygenation in dogs and might allow detection of changes that cannot be observed with CEUS. However, further research is needed to confirm the potential of ASL- and BOLD-MRI in dogs and to clarify which analysis method is most suitable for DCE-MRI in dogs.

Effect of Oligo-Fucoidan, Fucoxanthin, and L-Carnitine on Chronic Kidney Disease in Dogs: A Retrospective Study

Chronic kidney disease (CKD) commonly occurs in old dogs and cats. Oligo-fucoidan, fucoxanthin, and L-carnitine (OFL) compounds have a variety of reno-protective properties, including anti-inflammatory, anti-oxidative, and anti-fibrotic effects. Because their effects have not been investigated in naturally occurring canine CKD, we examined their reno-protective activities in dog patients with CKD. A total of 50 patients (OFL, n = 28; control, n = 22) were included in the analysis. A significant difference was identified in serum blood urea nitrogen and creatinine concentrations between the control and OFL groups at 6 months. No significant difference in electrolytes was found between the groups. A significant difference was identified in serum creatinine concentration between the control and OFL groups in azotemic (CKD IRIS stage 2-4) at 6 months. The OFL compounds showed a reno-protective effect, consistent with previous animal studies. The OFL combination can potentially delay the progression of canine CKD and be used as an adjuvant therapy.

A comprehensive analysis of albuminuria in canine chronic kidney disease

BACKGROUND

Albuminuria, an important marker of decreased kidney function in chronic kidney disease (CKD), is not routinely used for CKD detection or proteinuria appearance. Its relationships with biochemical parameters and blood pressure in dogs are poorly understood.

OBJECTIVES

This study aimed to evaluate the relationship of albuminuria with various CKD markers, its correlation with the urinary protein to creatinine ratio (UPC), and hypertension in dogs with early stages of CKD. It also sought to determine the usability of the urinary albumin to creatinine ratio (UAC) for CKD screening.

METHODS

The study reviewed records of 102 dogs, categorising them into four groups based on disease status. UAC and UPC ratio, biochemistry and haematology variables, age, and systolic blood pressure were determined.

RESULTS

The Pearson's correlation coefficient between log-transformed values of UPC and UAC was r = 0.902 (95% CI: 0.87 to 0.93). Median UAC ratio values were 2.1 mg/g for the Healthy control group (n = 17), 54.2 mg/g for early stages CKD (n = 42), 5.8 mg/g for Acute sick control (n = 30), and 104 mg/g for Chronic sick control (n = 13). Thresholding UAC ratio as an indicator for impaired kidney function with the threshold of 10 mg/g (established based on the receiver operating characteristic curve) had a sensitivity 81.8%, specificity of 89.4%, positive predictive value (PPV) 90%, and negative predictive value (NPV) 80.1%. The correlation of UAC with biochemistry and haematology variables was statistically significant; for SDMA (μg/L), it was r = 0.566 and for other variables, it was weak to moderate. UAC was markedly elevated in cases of severe hypertension.

CONCLUSIONS

UAC ratio was significantly different among dogs with impaired and not impaired kidney function. The correlation strength for the UAC and UPC ratios was high. UAC ratio may be a promising marker for proteinuria analysis in dogs with CKD or other kidney function alterations.

Baicalin Exhibits a Protective Effect against Cisplatin-Induced Cytotoxic Damage in Canine Renal Tubular Epithelial Cells

Renal failure is a common chronic disease in dogs that substantially affects both their quality of life and longevity. The objective of this study was to assess the protective mechanisms of baicalin in cisplatin-induced Madin-Darby canine kidney (MDCK) epithelial cells' apoptosis model and explore the impacts of baicalin at varying doses on various indexes, such as cisplatin-induced MDCK cell apoptosis, oxidation and antioxidation, and inflammatory factors. (Methods) MDCK cells in the logarithmic growth phase were randomly divided into a control group, a model group (20 μmol/L cisplatin), and a baicalin-protection group (20 μmol/L cisplatin + 50, 25 μmol/L baicalin) and received the corresponding treatments for 24 h. The effects of cisplatin on MDCK cell apoptosis, oxidation and antioxidation, inflammatory factors, and other indicators were studied, and the relieving effect of baicalin on cisplatin-induced MDCK cell damage was explored. Calcein/PI staining and Annexin V-FITC/PI staining showed that cisplatin induced the apoptosis of MDCK cells, while baicalin effectively reduced the damage caused by cisplatin. The ELISA results demonstrated a significant elevation in the nitric oxide (NO) and malondialdehyde (MDA) levels within the MDCK cells following treatment with cisplatin (p < 0.01). In addition, superoxide dismutase (SOD), glutathione peroxidase (GSH), and catalase (CAT) activities remarkably declined (p < 0.01), while tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) expression within the MDCK cells were apparently elevated (p < 0.01). However, baicalin treatment resulted in opposite changes in these factors. The findings suggested that baicalin exhibits potential in mitigating cisplatin-induced oxidative stress and inflammation in MDCK cells. As revealed with the Western blot results, cisplatin promoted P62, P53, and BAX protein levels, increased mTOR phosphorylation, inhibited AMPK phosphorylation, and reduced Beclin1 and BCL-2 protein levels. However, a contrasting trend was observed following baicalin treatment. Cisplatin can inhibit the activity of MDCK cells, lead to abnormalities in oxidation and antioxidation functions and cell inflammatory factors, and accelerate cell apoptosis. Moreover, baicalin can significantly alleviate the damage of cisplatin to MDCK cells.

Response and survival of dogs with proteinuria (UPC > 2.0) treated with angiotensin converting enzyme inhibitors

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEi) are a recommended treatment for glomerular proteinuria. Frequency of response to ACEi and the association of achieving proposed urine protein-to-creatinine ratio (UPC) targets on survival is unknown.

OBJECTIVES

To determine response rates to ACEi therapy and whether a positive response is associated with improved survival.

ANIMALS

Eighty-five dogs with proteinuria (UPC > 2.0).

METHODS

Retrospective study including dogs (UPC > 2.0) prescribed an ACEi for treatment of proteinuria. Baseline creatinine, albumin, cholesterol, UPC, and systolic blood pressure were recorded, and cases reviewed to track UPC. Treatment response was defined as achieving a UPC of <0.5 or reduction of ≥50% from baseline within 3 months. Outcome data were collected to determine overall and 12-month survival.

RESULTS

Thirty-five (41%) dogs responded to ACEi treatment. Treatment response was statistically associated with both median survival time (664 days [95% confidence interval (CI): 459-869] for responders compared to 177 [95% CI: 131-223] for non-responders) and 12-month survival (79% responders alive compared to 28% non-responders). Baseline azotemia or hypoalbuminemia were also associated with a worse prognosis, with odds ratios of death at 12 months of 5.34 (CI: 1.85-17.32) and 4.51 (CI: 1.66-13.14), respectively. In the 25 dogs with normal baseline creatinine and albumin, response to treatment was associated with 12-month survival (92% responders alive compared to 54% non-responders, P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

When the UPC is >2.0, achieving recommended UPC targets within 3 months appears to be associated with a significant survival benefit. Response to treatment is still associated with survival benefit in dogs with less severe disease (no azotemia or hypoalbuminemia).

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.

Evaluation of progression of chronic kidney disease in dogs with myxomatous mitral valve disease

Introduction

Cardiovascular and renal diseases are known to affect each other in the cardiovascular renal axis disorder (CvRD). Although CvRD, which includes myxomatous mitral valve disease (MMVD) and chronic kidney disease (CKD), has been described in dogs, there are only a few reports on the progression of CKD in accordance with the severity of MMVD. The aim of this study was to evaluate whether the presence of MMVD is associated with the rate of progression of CKD in dogs. The time from the initial diagnosis to the worsening of the International Renal Interest Society (IRIS) stage and the time for the occurrence of hyperphosphatemia and isosthenuria were evaluated.

Materials and methods

In this retrospective study, CKD progression was determined as an increase in the IRIS stage by at least one level and the development of hyperphosphatemia or isosthenuria. The CKD progression was compared in dogs with and without comorbid MMVD.

Results

Dogs with CKD were divided into two groups: dogs with and without MMVD (n = 63, concurrent group; n = 52, CKD group, respectively). The concurrent group was further divided into two subgroups based on the American College of Veterinary Internal Medicine guidelines (B1 group, n = 24; B2 group, n = 39). The time for progression of CKD from IRIS stage 1 to IRIS stage 2 was significantly shorter in the concurrent group than in the CKD group (log-rank test, p < 0.001). MMVD was associated with an increased risk of progression from stage 1 to stage 2 (hazard ratio, 6.442; 95% confidence interval (CI), 2.354 to 18.850; p < 0.001). The timing of the onset of hyperphosphatemia or isosthenuria in the concurrent group and the CKD group was not significantly different.

Conclusion

The results of this study suggest that MMVD could be a risk factor for the progression of CKD. Our findings may help predict the prognosis of dogs with both CKD and MMVD compared to CKD only.

A pilot study of alterations of the gut microbiome in canine chronic kidney disease

Introduction

Gut dysbiosis has been noted in humans and animals with chronic kidney disease (CKD). However, little is known about the gut microbiome in canine patients with CKD. This study aimed to analyze and compare the gut microbiome profiles of healthy and CKD dogs, including differences in the gut microbiome between each CKD stage.

Methods

The study was conducted on 29 client-owned dogs who underwent physical examination, complete blood count (CBC), serum biochemistry, and urinalysis. The gut microbiome profile of healthy dogs (n = 10) and dogs with CKD (n = 19) was analyzed employing 16S rRNA sequencing.

Results

Significant differences were seen in the composition of the gut microbiome, with increased operational taxonomic units from the phylum Proteobacteria (p = 0.035), family Enterobacteriaceae (p < 0.001), and genus Enterococcus (p = 0.002) in dogs with CKD, and a decrease in the genus Ruminococcus (p = 0.007). Furthermore, an increase in both the progression of CKD and abundance of genus Klebsiella (Jonckheere-Terpstra test statistic value (JT) = 2.852, p = 0.004) and Clostridium (JT = 2.018, p = 0.044) was observed.

Discussion

Our study demonstrated that in dogs with CKD, the composition of the gut microbiome varied depending on the stage of CKD. Alterations in gut microbiome composition observed in CKD patients are characterized by an increase in proteolytic bacteria and a decrease in saccharolytic bacteria. These findings suggest specific gut microbiota could be targeted for clinical management of uremic dogs with CKD.

Predicting health outcomes in dogs using insurance claims data

In this paper we propose a machine learning-based approach to predict a multitude of insurance claim categories related to canine diseases. We introduce several machine learning approaches that are evaluated on a pet insurance dataset consisting of 785,565 dogs from the US and Canada whose insurance claims have been recorded over 17 years. 270,203 dogs with a long insurance tenure were used to train a model while the inference is applicable to all dogs in the dataset. Through this analysis we demonstrate that with this richness of data, supported by the right feature engineering, and machine learning approaches, 45 disease categories can be predicted with high accuracy.

Proteinuria and Electrophoretic Pattern in Dogs with Comorbidities Associated with Chronic Kidney Disease

In animals with chronic pathologies, the detection of proteinuria via the proteinuria: creatininuria ratio (UPC) and urinary protein electrophoresis allows for the early diagnosis of chronic kidney disease (CKD). The objective of this work was to identify and determine the magnitude of proteinuria and its electrophoretic pattern characterization in dogs with chronic diseases pathophysiologically related to proteinuria. With the studied patients, five groups were formed. The control group (CG) contained non-proteinuric cases. The cases with proteinuria were classified into four groups according to the concurrent disease: chronic inflammatory diseases (IG), neoplasms (NG), heart diseases (HG), and endocrine diseases (EG). For the statistical analysis, descriptive statistics and non-parametric tests were used. Data from 264 dogs were obtained; in the disease groups, proteinuria was observed in more than 30% as the only finding of kidney disease, evidencing a greater risk factor for proteinuria in the HG group (OR 4.047, CI 1.894-8.644, p < 0.0001). In the HG, NG, and EG groups, a higher frequency of glomerular pattern (GEP) related to glomerular hypertension was observed; in the IG, a higher frequency of mixed pattern (MEP) was observed. These findings are secondary to the hyperfiltration process that affects the glomerulus and the renal tubule.

Diabetes Mellitus and the Kidneys

The pathomechanisms implicated in diabetic kidney disease in people are present in dogs and cats and, in theory, could lead to renal complications in companion animals with long-standing diabetes mellitus. However, these renal complications develop during a long period, and there is little to no clinical evidence that they could lead to chronic kidney disease in companion animals.

Use of urinalysis during baseline diagnostics in dogs and cats: an open survey

OBJECTIVES

To describe how veterinarians utilise and perform urinalyses for dogs and cats.

MATERIALS AND METHODS

A survey, developed and distributed through the Veterinary Information Network, enlisted veterinarians who perform urinalyses for dogs and cats. Participants were directed to question banks based on whether urinalyses were performed in-house, by an outside diagnostic laboratory, or using an in-house automated instrument. Participants using multiple methods were directed to questions that related to the chosen methods.

RESULTS

A total of 1059 predominantly first-opinion clinicians from the USA and Canada completed the survey. Participants performed urinalyses much less frequently than blood work during a routine examination. The most common factors preventing participants from performing a urinalysis with blood work included clients' financial constraints, difficulty obtaining urine and lack of perceived diagnostic need. The most common reasons for submission to a diagnostic laboratory included efficiency, more trusted results and convenience. Speed of obtaining results was the most common reason for performing urinalyses in-house. Of the participants who performed in-house urinalyses, fewer always performed a manual sediment examination (79%) as compared with urine-specific gravity (99%) and manual dipstick (87%).

CLINICAL SIGNIFICANCE

This survey documents that urinalysis is often not used in senior patients as recommended by recent clinical guidelines for dogs and cats which can result in decreased diagnosis and impaired management of subclinical disease. There is significant variability in urinalysis methods despite veterinary guidelines promoting standardisation, and this could lead to inaccurate results.

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.

Frequency, breed predispositions and other demographic risk factors for diagnosis of hypothyroidism in dogs under primary veterinary care in the UK

Background

Hypothyroidism is a commonly diagnosed endocrinopathy in dogs. This study aimed to investigate the frequency and risk factors for diagnosis of hypothyroidism in UK primary-care practice. Dogs diagnosed with hypothyroidism were identified by searching electronic patient records of primary-care practices participating in VetCompass. A cohort study design estimated one-year (2016) period prevalence and incidence risk for hypothyroidism. Multivariable binary logistic regression models were used to evaluate associations between demographic risk factors and hypothyroidism.

Results

From 905,553 dogs, 2,105 dogs were recorded with diagnosed hypothyroidism in 2016; 359 incident and 1,746 pre-existing, giving an annual prevalence of 0.23% (95% CI 0.22–0.24) and annual incidence risk of 0.04% (95% CI 0.04–0.04). Multivariable logistic regression identified 24 predisposed and nine protected breeds. Standard Doberman pinscher (odds ratio [OR] = 17.02, 95% CI 12.8–22.64), Tibetan terrier (11.25, 95% CI 8.27–15.32) and boxer (10.44, 95% CI 8.66–12.58) breeds showed high predisposition. Pug (OR 0.29, 95% CI 0.09–0.89), Yorkshire terrier (OR 0.38, 95% CI 0.24–0.59), Shih-tzu (OR 0.38, 95% CI 0.23–0.64) and Jack Russell terrier (OR 0.40, 95% CI 0.29–0.54) were the most protected breeds. Overall, being a purebred dog, being insured, having bodyweight above the breed-sex mean, increasing age, being neutered and rising adult bodyweight also showed increased odds being a dog living with a diagnosis of hypothyroidism.

Conclusions

Several strong breed predispositions for diagnosis of hypothyroidism were identified that can assist with disorder prioritisation in ongoing efforts to improve breed health. Other risk factors were also identified that can assist veterinary surgeons during clinical work-up of suspected cases. Identification of novel evidence for protected breeds provides useful information for research into genetic mechanisms.

Risk Factors Regarding Dog Euthanasia and Causes of Death at a Veterinary Teaching Hospital in Italy: Preliminary Results

The decision to request and proceed with euthanasia in a dog is complex and predictors of such decisions are important. This study investigates the risk factors (demographic and clinical) associated with the main clinical causes and methods of death (euthanasia or unassisted death) in a population of dogs. By comparing euthanasia to unassisted deaths, the authors assess causes of death to evaluate their relative impacts on decision-making to choose euthanasia compared with an unassisted death. For this, goal data from electronic medical records of dogs who had died (unassisted death and euthanasia), obtained from an Italian referral veterinary teaching hospital from 2010 to 2020, were analyzed. The causes of death were categorized by pathophysiological process and the organ system. Univariate and multivariable logistic regression analyses were performed to identify the factors that significantly affect the probability of undergoing euthanasia and to individuate independent significant predictors of euthanasia and unassisted death, respectively. Death rate by euthanasia was 40.7% (125/307), by died unassisted 50.8% (156/307), whilst only 8.5% of dogs (26/307) died accidentally. The main causes of death for euthanasia were due to neoplastic (75.6%), degenerative (64.3%), and congenital (60%) diseases. Furthermore, the findings reveal that in deaths by euthanasia, the significant risk predictors were female gender, age, and neoplastic and degenerative processes; while in unassisted deaths, the significant risk predictors were male gender, age, and infection/inflammatory conditions. These preliminary outcomes highlight the information of this study which may be used to evaluate strategic interventions and health promotion strategies to be implemented, with consequent welfare gains for the canine population.

Evaluation of presentation, treatment and outcome in hypertensive emergency in dogs and cats: 15 cases (2003-2019)

OBJECTIVES

Hypertensive emergency is well recognised in human medicine, yet there is limited veterinary evidence. This study aimed to determine the presentation, treatment and outcome in dogs and cats with hypertensive emergency.

MATERIALS AND METHODS

A retrospective case series of dogs and cats with hypertensive emergency identified as follows: acute history with non-invasive Doppler systolic blood pressure greater than 180 mmHg and target organ damage including acute onset seizures, altered mentation with or without lateral recumbency or blindness. Data collected included signalment, history, physical examination and clinicopathological findings, systolic blood pressure, antihypertensive treatment and outcome.

RESULTS

Seven dogs and eight cats were included presenting with seizures (n=9), blindness (n=4), altered mentation with (n=2) or without (n=2) lateral recumbency. Median age was 9 years (range 1 to 15) and duration of clinical signs before presentation was 1.5 days (range 1 to 15). Median systolic blood pressure on presentation was 230 mmHg (range 190 to 300). Amlodipine was the most common first-line agent (n=10), followed by hydralazine (n=4) and hypertonic saline (n=1). Aetiology of hypertensive emergency was acute kidney injury (n=9), idiopathic hypertension (n=3), hyperthyroidism (n=1), lymphoma (n=1) and suspected cutaneous and renal glomerular vasculopathy (n=1). Five cats and three dogs survived to discharge with an overall survival of 53.3%.

CLINICAL SIGNIFICANCE

Hypertensive emergencies had various presenting signs in this series. AKI was considered to be the cause of hypertension in the majority of patients. Further evaluation of treatment for hypertensive emergencies is warranted, considering almost half of the cases did not survive to discharge.

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.

The microvascular endothelial glycocalyx: An additional piece of the puzzle in veterinary medicine

The endothelial glycocalyx (eGlx) is a critically important structure lining the luminal surface of endothelial cells. There is increasing evidence, in human patients and animal models, for its crucial role in the maintenance of health. Moreover, its damage is associated with the pathogenesis of multiple disease states. This review provides readers with an overview of the eGlx; summarising its structure, essential functions, and evidence for its role in disease. We highlight the lack of studies regarding the eGlx in cats and dogs, particularly in naturally occurring diseases. Importantly, we discuss techniques to aid its study, which can be applied to veterinary species. Finally, we present targeted therapies aimed at preserving, and in some cases, restoring damaged eGlx.

Evaluation of Renal Blood Flow in Dogs during Short-Term Human-Dose Epoprostenol Administration Using Pulsed Doppler and Contrast-Enhanced Ultrasonography

Simple Summary

Since there is a lack of information regarding how epoprostenol, a prostacyclin, affects canine renal blood flow (RBF), we investigated the effects of short-term administration of epoprostenol at human doses of 2, 5, and 10 ng/kg/min intravenously for 20 min on RBF in six healthy dogs under anesthesia. The effects of short-term administration were investigated. As the dose of epoprostenol increased, peak systolic and end diastolic velocities of the renal arteries, maximum and minimum venous flow velocities of the interlobular and renal veins, and heart rate all tended to increase. However, these increases were not significant. These results indicate that the administration of human doses of epoprostenol to dogs does not produce significant changes in renal or systemic circulation.

Abstract

Prostacyclin is an in vivo bioactive substance that regulates renal blood flow (RBF). Information regarding how epoprostenol, a prostacyclin preparation, affects RBF in dogs is lacking. We investigated the effects of short-term epoprostenol administration on RBF in six healthy dogs under anesthesia by administering it intravenously at human doses—2, 5, and 10 ng/kg/min for 20 min. RBF was evaluated before and during epoprostenol administration using pulsed Doppler ultrasonography, and renal perfusion was evaluated using contrast-enhanced ultrasonography. Effects on renal and systemic circulation were evaluated by measuring systolic arterial, mean arterial, diastolic arterial, pulmonary arterial, mean right atrial, and pulmonary capillary wedge pressures; heart rate; and cardiac output. Kruskal–Wallis and Bonferroni multiple comparison tests and Spearman’s rank correlation coefficient were used for statistical analyses. As epoprostenol dosage increased, the peak systolic and end diastolic velocity of the renal artery, maximum and minimum venous flow velocities of the interlobular and renal veins, and heart rate all tended to increase, although not significantly. Our results indicate that human-dose epoprostenol administration in dogs does not cause significant changes in renal or systemic circulation. However, the human doses used may have been too low to produce a clinical effect in dogs.

Long-term outcome of dogs recovering from acute kidney injury: 132 cases

Background

Information regarding long‐term outcome of dogs recovering from acute kidney injury (AKI) is limited.

Objectives

Determine the long‐term outcome of dogs recovering from AKI and identify predictors for serum creatinine concentration (sCr) normalization and long‐term outcome.

Animals

One hundred thirty‐two dogs with AKI that survived ≥30 days postdischarge.

Methods

Retrospective study. Search of medical records of dogs diagnosed with AKI that survived to discharge. Follow‐up data were retrieved from medical records and by telephone interviews with the owners or primary care veterinarians or both.

Results

Estimated median survival time (MST) was 1322 days (95% confidence interval [CI], 1147‐1626), and 76% of the dogs were alive at last contact. Normalization of sCr was documented in 55% of the dogs at discharge and in additional 20% during the follow‐up period. The proportion of dogs with sCr normalization decreased with increase in AKI grade (P = .02). Long‐term survival was not associated with sCr normalization (P = .63). Etiology was associated with the long‐term outcome (P = .004).

Conclusion and Clinical Importance

Long‐term survival of dogs with AKI is longer than previously described. Normalization of sCr in 99 dogs (75%) occurred, either at discharge or within the follow‐up period. Normalization of sCr was not associated with long‐term survival. Estimated MST of dogs with sCr normalization was not different compared with dogs that developed azotemic chronic kidney disease (CKD), presumably because of slow CKD progression rate. Etiology is an important factor determining sCr normalization and long‐term survival, emphasizing the importance of the reversibility of renal injury rather than its severity.

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.

Dog Models of Aging

As the most phenotypically diverse mammalian species that shares human environments and access to sophisticated healthcare, domestic dogs have unique potential to inform our understanding of the determinants of aging. Here we outline key concepts in the study of aging and illustrate the value of research with dogs, which can improve dog health and support translational discoveries. We consider similarities and differences in aging and age-related diseases in dogs and humans and summarize key advances in our understanding of genetic and environmental risk factors for morbidity and mortality in dogs. We address health outcomes ranging from cancer to cognitive function and highlight emerging research opportunities from large-scale cohort studies in companion dogs. We conclude that studying aging in dogs could overcome many limitations of laboratory models, most notably, the ability to assess how aging-associated pathways influence aging in real-world environments similar to those experienced by humans.

Veterinary drug therapies used for undesirable behaviours in UK dogs under primary veterinary care

Undesirable behaviours (UBs) in dogs are common and important issues with serious potential welfare consequences for both the dogs and their owners. This study aimed to investigate the usage of drug therapy for UBs in dogs and assess demographic risk factors for drug-prescribed UBs within the dog population under primary-care veterinary care in the UK in 2013. Dogs receiving drug therapy for UB were identified through the retrospective analysis of anonymised electronic patient records in VetCompass™. Risk factor analysis used multivariable logistic regression modelling. The study population comprised 103,597 dogs under veterinary care in the UK during 2013. There were 413 drug-prescribed UBs recorded among 404 dogs. The prevalence of dogs with at least one UB event treated with a drug in 2013 was 0.4%. Multivariable modelling identified 3 breeds with increased odds of drug-prescribed UB compared with crossbred dogs: Toy Poodle (OR 2.75), Tibetan Terrier (OR 2.68) and Shih-tzu (OR 1.95). Increasing age was associated with increased odds of drug-prescribed UB, with dogs ≥ 12 years showing 3.1 times the odds compared with dogs < 3 years. Neutered males (OR 1.82) and entire males (OR 1.50) had increased odds compared with entire females. The relatively low prevalence of dogs with at least one UB event that was treated with a drug in 2013 could suggest that opportunities for useful psychopharmaceutical intervention in UBs may be being missed in first opinion veterinary practice. While bodyweight was not a significant factor, the 3 individual breeds at higher odds of an UB treated with a behaviour modifying drug all have a relatively low average bodyweight. The current results also support previous research of a male predisposition to UBs and it is possible that this higher risk resulted in the increased likelihood of being prescribed a behaviour modifying drug, regardless of neuter status.

Familial nephropathy in Bracchi Italiani: 8 cases (2012-2019)

OBJECTIVE

To characterize the signalment, clinical signs, clinical pathological and histologic findings, and outcome in 8 related Bracchi Italiani with proteinuric kidney disease.

ANIMALS

8 client-owned Bracchi Italiani.

PROCEDURES

Health records submitted to the Bracco Italiano Health Foundation and the Bracco Italiano Club of America between 2012 and 2019 were reviewed for dogs with evidence of nephropathy for which histologic diagnoses were obtained. Pedigree, signalment, clinical signs, diagnostic test results (including microscopic examination of kidney tissue samples collected ante- or postmortem), and outcome were acquired. Results were presented as descriptive statistics.

RESULTS

The most common clinical sign in affected dogs was inappetence. All dogs were proteinuric, and 4 dogs were azotemic. Seven dogs developed clinical signs of kidney disease and were euthanized a median of 75 days postdiagnosis. Six dogs had glomerular amyloidosis, and 1 dog each had nephrosclerosis and nonamyloidotic fibrillar glomerulopathy.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the clinical presentation may vary in affected dogs, and proteinuria in young or middle-aged Bracchi Italiani should raise the concern for hereditary nephropathy. Prognosis is likely poor once clinical signs are noted.

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.

Analysis of canine cardiovascular therapeutic agent prescriptions using electronic health records in primary care veterinary practices in the United Kingdom

INTRODUCTION/OBJECTIVES

Canine cardiovascular (CV) diseases are often managed in primary care settings. The objectives were to describe CV therapeutic agent (CVTA) prescribing patterns in primary care practices in the United Kingdom (UK) and to evaluate recorded clinical signs, diagnostic tests and justifications for use of torasemide, a recently marketed and authorised loop-diuretic in the UK.

ANIMALS, MATERIALS AND METHODS

Electronic health records (EHRs) describing 3,579,420 consultations (1,043,042 unique dogs) were collated (1 April 2014 and 31 December 2018) by the Small Animal Veterinary Surveillance Network from 270 veterinary practices. Consultations prescribing at least one CVTA were identified. Annual variation in individual CVTA prescriptions was analysed using mixed-effects binomial regression models. Free-text clinical narratives were manually read to determine the first-prescribing event for torasemide.

RESULTS

Twenty-nine thousand and seven consultations (0.81% of all consultations, 95% confidence interval [CI], 0.76-0.86) prescribed CVTA in 14,148 (1.36%) dogs. Furosemide (52.8% of CV-prescribing consultations, 95% CI 50.7-54.9) and pimobendan (51.9%, 95% CI 50.1-53.7) were most prescribed. Longitudinal analysis (2014-2018) showed a significant negative temporal trend for angiotensin-converting enzyme inhibitors (p < 0.001), and furosemide (p = 0.003) and a positive temporal trend for pimobendan (p = 0.020) and torasemide (p < 0.001). First prescriptions of torasemide were identified in 16.5% of torasemide-prescribing consultations. Where justification for prescription of torasemide was identified (32.5%), furosemide resistance was the most common (92.0%).

CONCLUSIONS

EHRs can be used to temporally monitor prescribing habits, including responses to market authorisations. Despite authorisation in the UK for torasemide use as a first-line diuretic, it was most commonly prescribed after furosemide resistance.

Cystatin C and Neutrophil Gelatinase-Associated Lipocalin as Early Biomarkers for Chronic Kidney Disease in Dogs

Early diagnosis of chronic kidney disease (CKD) could facilitate timely and appropriate monitoring and therapy. Traditional biomarkers have limitations. Thus, new biomarkers are needed. The objective of the present study was to compare renal biomarkers (including symmetric dimethylarginine [SDMA], cystatin C [CysC], and urine neutrophil gelatinase-associated lipocalin [NGAL]-creatinine ration [UNCR]) and creatinine (CREA) for early detection of CKD in dogs. Nine healthy dogs and 32 dogs with CKD were included in this study. All dogs underwent physical examination, blood analysis (included CREA and SDMA), urinalysis, and imaging examinations. CysC and NGAL levels were measured in serum and urine, respectively. SDMA, CysC, and UNCR were significantly elevated in dogs with CKD and IRIS stage Ι (P < .0001) than in controls. CysC demonstrated a strong correlation with CREA (r² = 0.6556, P < .0001). CysC (sensitivity 93.55%, specificity 100%) had the highest sensitivity for detecting CKD, followed by UNCR (sensitivity 90%, specificity 100%), SDMA (sensitivity 84.37%, specificity 100%), and CREA (sensitivity 43.75%, specificity 100%). Additionally, CysC and UNCR (sensitivity 88.89%, specificity 100%) exhibited higher sensitivity and specificity than CREA (sensitivity 88.89%, specificity 66.67%) and SDMA (sensitivity 88.89%, specificity 88.89%) in dogs with CKD International Renal Interest Society (IRIS) stage Ι. CysC as a marker of glomerular filtration rate (GFR) and urinary NGAL as a marker of tubular damage could be used to detect CKD early in dogs better than CREA and SDMA.

Longitudinal evaluation of symmetric dimethylarginine and concordance of kidney biomarkers in cats and dogs

Symmetric dimethylarginine (SDMA) is a sensitive surrogate marker for glomerular filtration rate; however, there are uncertainties as to how to interpret mild increases (SDMA 15-19 μg/dL). This descriptive study used retrospective data to evaluate whether cats or dogs that had initial SDMA values (at T0) within the reference interval followed by an increased SDMA (at T1) had persistently increased SDMA (at T2; measured from 14 days to 18 months following T1; Persistence Cohort), and if and when cats or dogs with persistently increased SDMA had increased creatinine up to 24 months (Concordance Cohort). The Persistence Cohort included 16,670 cats and 16,712 dogs. If SDMA at T1 was 15-19 μg/dL, the probability of persistence was 53% for cats and 42% for dogs, while creatinine was concurrently increased in 20% of cats and 18% of dogs. For comparison, if SDMA was not increased at T1 the probability of increased SDMA at recheck was only 20% for cats and 9% for dogs. For cats and dogs with a T1 SDMA of 15-19 μg/dL and with persistent increases at T2, the probability of increased creatinine at T1 was 20% for cats and 18% for dogs, rising to 61% and 55%, respectively, by 24 months. When SDMA at T1 was >25 μg/dL, creatinine was increased in 93% of cats and 92% of dogs by 24 months. Mildly increased SDMA results may provide an opportunity to identify some cats and dogs earlier in their kidney disease.

The impact of periodontal disease and dental cleaning procedures on serum and urine kidney biomarkers in dogs and cats

The objective of this study was to evaluate the benefits and inherent risks of dental cleaning procedures, based on serum and urine biomarkers for kidney function and tissue damage, in dogs and cats. Thirty-one asymptomatic, mostly older dogs (14 neutered male and 17 ovariohysterectomized female dogs of various breeds between 3 and 14 years old) and cats (19 neutered male and 12 ovariohysterectomized female domestic short hair cats between 2 and 16 years old) diagnosed with periodontal disease on physical exam, and recommended by their veterinarian to have dental cleaning under general anesthesia were evaluated in a prospective study. Serum and urine samples were collected from dogs and cats 1 week before, 6 hours after, and again 1 week after the dental cleaning procedure. Samples were analyzed for biomarkers of kidney function [serum creatinine (Cr), symmetric dimethylarginine (SDMA), and blood urea nitrogen (BUN), and urine for specific gravity (USG) and protein:creatinine (UPC) ratio]. A panel of biomarkers for renal tissue damage was also assessed [serum β-aminoisobutyric acid (BAIB), and urine cystatin B and clusterin]. Samples collected one week before dental cleaning procedures showed that increased age and severity of dental disease were linked to abnormal kidney function biomarker values (age: elevated SDMA and Cr concentrations and isosthenuric USG values; disease severity: elevated UPC ratios) as well as elevated urine cystatin B and clusterin concentrations. Directly after the dental cleaning procedure, an increased number of cats with elevated SDMA concentrations was observed (specifically in cats with longer duration of dental procedures). Extended duration of dental procedures (≥60 min) was linked to increased urine cystatin B and clusterin concentrations, whereas shorter duration procedures was linked to decreased urine cystatin B and clusterin. Higher SDMA concentrations persisted in cats one week after the dental cleaning procedures and were linked to elevated UPC ratios one week before cleaning procedures. In conclusion, the results of this study indicate a link between severity of dental disease, renal tissue injury, and impaired renal function. Longer duration dental procedures in cats may carry inherent risks of kidney injury and impaired renal function.

No Observed Adverse Effects on Health Were Detected in Adult Beagle Dogs When Fed a High-Calcium Diet for 40 Weeks

Simple Summary

Calcium (Ca) is an essential mineral that plays a vital role in many bodily functions. There is evidence that high levels of dietary Ca for puppies and growing dogs can result in adverse growth and health effects, with certain breeds and dog size categories being most susceptible, for example, large breed sizes or beagles. Until recently, little was known about the health consequences of high Ca diets to adult dog, however, a study in the large sized breed Labrador retriever found no adverse health consequences when feeding diets containing levels of Ca near maximum levels set by pet food regulators (2.5 g per 100 g dry matter) for 40 weeks. This current study fed a similar high Ca diet to adult beagles, a medium sized breed for 40 weeks and monitored the dogs’ health using an extensive suite of health parameters. All dogs remained healthy and did not display any clinically relevant signs of adverse health relating to diet at any point during or following completion of the study.

Abstract

The implications of long-term high calcium (Ca) intake are well documented in growing dogs and in adult dogs of large breed size, however, the consequences on other breeds and breed sizes are yet to be determined. Eighteen neutered adult beagles, nine males and nine females aged 1.4–4.4 years, were randomized to control or test diets providing in g∙4184 kJ⁻¹ (1000 kcal⁻¹): 1.44 and 7.19 total Ca balanced with 1.05 and 4.25 total phosphorus, respectively, for 40 weeks. Health parameters, ultrasound scans, radiographs, glomerular filtration rate, and mineral balance were measured at eight-week intervals. All dogs remained healthy with no measured evidence of orthopedic, urinary, or renal disease. The test diet resulted in a 5.2 fold increase in fecal Ca excretion. Apparent Ca digestibility (%) and Ca balance (g/d) did not significantly (p > 0.05) change from baseline in the test diet group, although dogs displayed a positive Ca balance (maximum at week 8, 1.11 g/d with 95% CI (0.41, 1.80)) before a neutral Ca balance was restored at week 32. Despite an initial positive Ca balance, we can conclude that no measurable adverse health effects were observed as a result of the test diet fed in this study in beagles over a period of 40 weeks.

Absence of renal cortical anisotropic backscattering artifact in feline chronic kidney disease

Renal cortical anisotropy backscattering artifact (CABA) is a focal hyperechoic region where the tubules are parallel to the incident ultrasound beam, reflecting most of the beams to the transducer. To investigate the association between chronic kidney disease (CKD) and the absence of renal CABA in cats. Ultrasonographic renal images of 40 cats with CKD (stage II-IV) and 36 clinically healthy cats were blindly evaluated by two observers to determine the visibility of renal CABA. Inter- and intraobserver agreements were evaluated using McNemar's test. The association between the absence of renal CABA and CKD was assessed using Fisher's exact test. Excellent intraobserver and substantial interobserver agreements were demonstrated. A significant association (P < .0001) between absent renal CABA and CKD stage was revealed in all cats. Cats with CKD had an increased risk of the absence of renal CABA (Odds ratio, 56.0; 95% CI, 13.8-227.0) compared with the clinically healthy cats. The absence of renal CABA revealed 87.5% sensitivity and 88.9% specificity to detect CKD in all cats, and 91.7% sensitivity and 83.3% specificity in aged cats. Our study demonstrated a correlation between feline CKD and the absence of renal CABA, providing a feasible and alternative method for feline CKD evaluation.

Evaluation of Chronic Kidney Disease Progression in Dogs With Therapeutic Management of Risk Factors

This research was performed to describe the characteristics of the progression of naturally occurring chronic kidney disease (CKD) in dogs, together with the management of identified risk factors, following the International Renal Interest Society recommendations. Dogs diagnosed and staged with CKD, and with a longitudinal follow-up from the moment of diagnosis of up to a maximum of 730 days, were included. A total of 545 dogs that presented risk factors for the development of CKD were analyzed, out of which 36 met the inclusion criteria. Advanced age was identified in 80.6% of cases. Initiation risk factors were represented by inflammatory/infectious diseases, history of anesthetic-surgical procedures, heart disease, neoplasms, endocrinopathies, and exposure to nephrotoxic drugs. During the follow-up period, progression of CKD was identified in 47.2% of the cases, being more salient in advanced stages. Serum symmetric dimethyl arginine (SDMA) was the only glomerular filtration rate (GFR) marker which displayed differences among studied times during early stages of CKD, associated with the disease progression and decline of renal function. A significant difference between the survival curves in early and advanced CKD stages was observed. The factors related to decreased survival were hyperphosphatemia, anemia, and low body condition score (BCS). No differences were found between the presence of arterial hypertension and renal proteinuria and decreased survival. Furthermore, CKD diagnosis based on the persistent finding of abnormalities in early disease markers, such as serum symmetric dimethyl arginine increase and/or renal proteinuria, and timely therapeutic management of risk factors, allowed for CKD stabilization, reducing progression to advanced stages, and favoring higher survival rates.

Evaluation of symmetric dimethylarginine and creatinine in dogs with primary hypoadrenocorticism receiving long-term mineralocorticoid replacement therapy

OBJECTIVES

To investigate kidney function by determining serum symmetric dimethylarginine (sSDMA) and serum creatinine (sCr) concentrations in dogs with primary hypoadrenocorticism (PH) receiving long-term mineralocorticoid replacement therapy.

METHODS

Dogs with PH receiving a minimum of 12 months of either desoxycorticosterone pivalate or fludrocortisone acetate were included in the study provided that banked frozen serum samples were available for sSDMA analysis. sCr concentrations were retrieved from the medical records. In dogs still alive and presented for regular re-evaluations and in newly diagnosed patients, blood was prospectively collected for sSDMA and sCr determination.

RESULTS

Thirty-two dogs met the inclusion criteria. The treatment time ranged from 12 to 146 months after initial diagnosis (median, 55.5 months). The majority of dogs had normal sSDMA and sCr concentrations throughout the hormone replacement treatment. Both sSDMA and sCr concentrations were persistently elevated in three of 32 dogs. Further workup confirmed chronic kidney disease (CKD) in all three dogs.

CONCLUSIONS

Based on these data, the prevalence of CKD could be higher in dogs with PH receiving long-term mineralocorticoid replacement treatment than in the general dog population. However, additional studies with a larger number of dogs are needed to confirm it.