A Clinical Study on Urinary Clusterin and Cystatin B in Dogs with Spontaneous Acute Kidney Injury

Novel biomarkers are needed in diagnosing reliably acute kidney injury (AKI) in dogs and in predicting morbidity and mortality after AKI. Our hypothesis was that two novel tubular biomarkers, urinary clusterin (uClust) and cystatin B (uCysB), are elevated in dogs with AKI of different etiologies. In a prospective, longitudinal observational study, we collected serum and urine samples from 18 dogs with AKI of different severity and of various etiology and from 10 healthy control dogs. Urinary clusterin and uCysB were compared at inclusion between dogs with AKI and healthy controls and remeasured one and three months later. Dogs with AKI had higher initial levels of uClust (median 3593 ng/mL; interquartile range [IQR]; 1489-10,483) and uCysB (554 ng/mL; 29-821) compared to healthy dogs (70 ng/mL; 70-70 and 15 ng/mL; 15-15; p < 0.001, respectively). Initial uCysB were higher in dogs that died during the one-month follow-up period (n = 10) (731 ng/mL; 517-940), compared to survivors (n = 8) (25 ng/mL; 15-417 (p = 0.009). Based on these results, uClust and especially uCysB are promising biomarkers of AKI. Further, they might reflect the severity of tubular injury, which is known to be central to the pathology of AKI.

Novel renal injury markers in dogs with ehrlichiosis

Canine monocytic ehrlichiosis (CME) has been observed to impact renal function. Currently, the recognition of acute kidney injury is through the nonspecific biomarker serum creatinine (sCr). Novel markers of renal injury such as urinary clusterin (uClust) and urinary cystatin B (uCysB) may increase our understanding of the relationship between ehrlichiosis and renal cellular injury. The aim of this study was to evaluate novel renal injury biomarkers in dogs with acute CME. Twenty healthy dogs were enrolled in the control group (CG), and 16 dogs naturally infected with Ehrlichia canis were included in the Ehrlichia Group (EG). All dogs were followed for 45 days. EG dogs were treated with doxycycline twice daily for the first 30 days. Urine and serum were collected at: 0, 0.5, 1, 15, 30, and 45 days after start of treatment. Urine concentrations of uClust and uCysB were determined using a research ELISA immunoassay. A linear mixed model was used to estimate population mean of renal injury markers with patient as the random effect, and day and treatment as fixed effects. EG was observed to have higher uClust values compared to CG (estimated population mean EG: 213 ng/dL vs. CG: 84 ng/dL, P < 0.001). EG was observed to have higher uCysB values compared to CG (estimated population mean EG: 248 ng/dL vs. CG: 38 ng/dL, P < 0.001). Increases in uCysB and uClust suggest the presence of renal injury and a possible mechanism for the observed predisposition to chronic kidney disease in dogs with ehrlichiosis.

Endotoxic kidney injury in Beagle dogs assessed by serum creatinine and symmetric dimethylarginine, and urinary neutrophil gelatinase-associated lipocalin and clusterin

Sepsis of Gram negative bacterial origin results in lipopolysaccharide-induced endotoxemia. This often leads to acute kidney injury (AKI) and its recognition remains a challenge and delays treatment. As renal damage occurs before a rise in serum creatinine is detected, new early biomarkers of kidney injury need to be explored. The aim of this study was to determine changes in serum parameters of renal function and urine biomarkers of renal injury. This was a descriptive study. Endotoxemia was induced intravenously in six anaesthetized Beagles (T1). To achieve normotension, dogs received fluids (T2), followed by a continuous infusion of noradrenaline and dexmedetomidine or 0.9% NaCl (T3). Ten minutes later, the dogs received fluids (T4) and noradrenaline and dexmedetomidine or 0.9% NaCl in a crossover manner (T5). At each timepoint, blood and urine were collected for serum creatinine, urea, symmetric dimethylarginine, urine protein/creatinine (UPC) ratio, urine neutrophil-gelatinase-associated lipocalin (U-NGAL), U-NGAL/creatinine ratio, urine clusterin (U-clusterin) and U-clusterin/creatinine ratio. Data were analyzed using a mixed-effect model taking into account time and stage of veterinary AKI (VAKI). Three of six dogs had a VAKI stage ≥1; one with anuria and elevated creatinine. Serum creatinine (P < 0.001), U-NGAL/creatinine ratio (P = 0.01) and U-clusterin/creatinine ratio increased over time (P < 0.01). The UPC ratio (mean (range) 0.68 (0.35-2.3) versus 0.39 (0.15-0.71) P < 0.01) and U-NGAL (3164 pg/mL (100-147,555) versus 100 (100-14,524), P = 0.01) were higher in VAKI stage ≥1 versus stage 0, respectively. Endotoxemia induced VAKI stage ≥1 in half of the dogs. Repeated measurement of selected parameters could detect AKI early.

Renal biomarkers in cats: A review of the current status in chronic kidney disease

Serum creatinine concentration, the classical biomarker of chronic kidney disease (CKD) in cats, has important limitations that decrease its value as a biomarker of early CKD. Recently, serum symmetric dimethylarginine concentration was introduced as a novel glomerular filtration rate biomarker for the early detection of CKD in cats. However, data on its specificity are still limited. The limitations of conventional biomarkers and the desire for early therapeutic intervention in cats with CKD to improve outcomes have prompted the discovery and validation of novel renal biomarkers to detect glomerular or tubular dysfunction. Changes in the serum or urinary concentrations of these biomarkers may indicate early kidney damage or predict the progression of kidney before changes in conventional biomarkers are detectable. This review summarizes current knowledge on renal biomarkers in CKD in cats, a field that has progressed substantially over the last 5 years.

Prospective evaluation of novel biomarkers of acute kidney injury in dogs following cardiac surgery under cardiopulmonary bypass

OBJECTIVE

To assess the occurrence of acute kidney injury (AKI) in dogs undergoing cardiac surgery under cardiopulmonary bypass (CPB) and explore associations between traditional and novel serum and urinary biomarkers.

DESIGN

Prospective cohort study conducted between July 2018 and April 2019.

SETTING

University teaching hospital.

ANIMALS

Nineteen dogs undergoing cardiac surgery under CPB with preoperative serum creatinine <140 μmol/L (<1.6 mg/dl).

INTERVENTIONS

Blood and urine samples were obtained at 4 time points: preoperatively following general anesthesia induction, immediately postoperatively, and 2 and 4 days postoperatively (T₁ , T₂ , T₃ , and T₄ ). AKI was defined as an increase in serum creatinine ≥26.4 μmol/L (≥0.3 mg/dl) above baseline within 48 hours. Serum creatinine, C-reactive protein (CRP), symmetric dimethylarginine (SDMA), inosine, beta-aminoisobutyric acid (BAIB), urinary clusterin (uClus), and urinary cystatin B (uCysB) were measured. Data were log-transformed (log₁₀ ) when appropriate and assessed using linear mixed-effects models.

MEASUREMENTS AND MAIN RESULTS

AKI occurred in 3 of 19 dogs (15.8%, 95% confidence interval: 0.047-0.384). Inosine increased at T₂ (adjusted mean ± standard error: 53 ± 5.6) in all dogs, and then gradually decreased. Log₁₀ uCysB increased at T₂ (2.3 ± 0.1) in all dogs and remained high. Log₁₀ CRP and log₁₀ uClus increased significantly at T₃ (1.9 ± 0.1 and 3.6 ± 0.1, respectively) in all dogs and remained increased. There was a significant positive association between serum creatinine and SDMA (P < 0.001, estimate ± standard error: 0.06 ± 0.00), between log₁₀ CRP and log₁₀ uClus (P < 0.001, 0.35 ± 0.08), between SDMA and creatinine as well as between SDMA and BAIB (P < 0.001, 11.1 ± 0.83 and P < 0.001, 1.06 ± 0.22, respectively) for all dogs at all time points.

CONCLUSIONS

Inosine and uCysB concentrations changed in all dogs immediately following a surgery under CPB and may indicate tubular injury. Further studies are required to ascertain the usefulness of those biomarkers in early detection of AKI.

Evaluation of Urinary Clusterin and Cystatin B as Biomarkers for Renal Injury in Dogs Envenomated by the European Adder (Vipera berus)

Dogs are commonly bitten by the European adder (Vipera berus) but studies investigating the effects of envenomation are limited. Snakebite-related kidney injury is reported in dogs but diagnosis of acute kidney injury (AKI) might be limited by the insensitivity of routinely used renal function biomarkers. The aim of this study was to evaluate novel biomarkers of renal injury (urinary cystatin B and urinary clusterin) and biomarkers of renal function (serum creatinine and serum symmetric dimethylarginine), and urine protein to creatinine ratio in dogs envenomated by V. berus. Biomarkers were measured at presentation (T1), 12 hours (T2), 24 hours (T3), 36 hours (T4), and 14 days (T5) after snakebite and compared to a group of healthy control dogs. A secondary aim was to investigate the association between biomarker concentrations and severity of clinical signs of envenomation using a snakebite severity score (SSS). Urinary cystatin B concentrations were significantly higher at all timepoints in envenomated dogs compared to controls (P < .010), except for T5 (P = .222). Absolute urinary clusterin concentrations were not significantly different to controls at any timepoint. Compared to controls, serum creatinine and serum symmetric dimethylarginine concentrations were significantly lower in envenomated dogs at T1-T4 (P < .036) and T2-T4 (P < .036), respectively. Urine protein to creatinine ratio was higher in envenomated dogs compared to controls at T2 and T3. Urinary cystatin B concentrations at T1 were correlated with SSS (Spearman's ρ = 0.690, P < .001). The increased urinary cystatin B concentrations observed in dogs envenomated by V. berus in comparison to controls may indicate renal tubular injury in these patients.

Analytical validation and reference intervals for a commercial multiplex assay to measure five novel biomarkers for acute kidney injury in canine urine

Novel urinary biomarkers are increasingly utilized for the diagnosis of acute kidney injury (AKI) in dogs. Magnetic-bead based immunoassays for the simultaneous measurement of multiple biomarkers represent a potentially efficient and cost effective tool for investigators; however there is limited data to support their reliable use in dogs. Analytical validation of a commercial multiplex assay for the measurement of five AKI biomarkers: clusterin, cystatin C, kidney-injury molecule 1 (KIM-1), monocyte chemoattractant protein 1 and neutrophil gelatinase-associated lipocalin (NGAL) in canine urine was performed. The effect of pre-analytical factors including potential interfering substances and sample storage methods were investigated. Urine from 110 healthy dogs was used to determine reference intervals for each biomarker measured, according to American Society of Veterinary Clinical Pathology guidelines. Additionally, urine from 21 dogs with pyuria was used to evaluate the impact of pyuria on biomarker concentration. The assay performed with acceptable accuracy and precision for the measurement of NGAL only. Clinically relevant urine concentrations of bilirubin, haemoglobin, and synthetic colloid solutions led to interference (mean percentage difference > +/- 15% compared to control) with measurement of all or some of the biomarkers. All biomarkers were stable in urine stored at 20-22 °C for 2 h, 4 °C for 12 h, or -20 °C for 6 months. Reference intervals could not be established for KIM-1 due to unacceptable measurement imprecision (intra- and inter assay coefficient of variation 45% and 20% respectively). Urine NGAL concentration was significantly elevated in pyuria (P < 0.001).

Prospective randomized controlled blinded clinical trial evaluating biomarkers of acute kidney injury following 6% hydroxyethyl starch 130/0.4 or Hartmann's solution in dogs

OBJECTIVE

To evaluate the effect of 6% hydroxyethyl starch (HES) 130/0.4, compared with a Hartmann's solution control (CRYST), on urine biomarkers of acute kidney injury (AKI) in dogs prescribed a fluid bolus.

DESIGN

Randomized, controlled, blinded clinical trial January 2018 to February 2019.

SETTING

University teaching hospital.

ANIMALS

Forty client-owned dogs.

INTERVENTIONS

Dogs prescribed a fluid bolus were randomized to receive at least 10 mL/kg of HES or CRYST with clinicians and investigators blinded to fluid type. Study fluid was used for further boluses as required in the following 24 hours, to a limit of 40 mL/kg total, after which fluid administration was open-label.

MEASUREMENTS AND MAIN RESULTS

Urine was collected prior to and 6, 12, and 24 hours after the first study fluid bolus. Urine concentrations of AKI biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, kidney injury molecule-1 (KIM), clusterin, and osteopontin were measured using a magnetic bead multiplexed assay. Osmolality-indexed biomarker concentrations were compared between groups over time with linear mixed-effects models, with P < 0.05 considered significant. The mean volume of study fluid administered was not significantly different between groups (HES: 23.1 mL/kg, CRYST: 25.9 mL/kg; P = 0.47, t-test). There were no significant differences between groups in change over time of osmolality-indexed urine concentrations of NGAL (P = 0.91), cystatin C (P = 0.95), KIM (P = 0.77), clusterin (P = 0.63), or osteopontin (P = 0.91). The maximum Veterinary Acute Kidney Injury (VAKI) score up to 7 days during hospitalization (P = 1.0) and in-hospital mortality (P = 0.49) were not significantly different between groups, as compared by Fisher's exact test.

CONCLUSIONS

There were no differences in change over time of urine AKI biomarkers in dogs treated with 10 - 40 mL/kg HES or CRYST over 24 hours. Larger clinical trials with patient-centered outcomes are required to investigate the safety of HES in dogs.

Urinary clusterin and cystatin B as biomarkers of tubular injury in dogs following envenomation by the European adder

Diagnosing acute kidney injury remains a challenge since the established renal biomarkers, serum creatinine (sCr) and symmetric dimethylarginine (SDMA) reflect glomerular function and not tubular injury. Sensitive tubular markers such as urinary clusterin (uClust) and cystatin B (uCysB) have been proposed to detect AKI at an earlier stage. Since envenomation by the European adder (Vipera berus berus) could serve as a spontaneous disease model of AKI we investigated these new biomarkers in affected dogs. Concentrations of uClust and uCysB as well as sCr and SDMA were analyzed retrospectively in stored samples from 26 dogs with snake envenomation and 13 healthy controls. Higher concentrations of uClust (P < 0.012) and uCysB (P < 0.001) were observed in the snake-envenomed group. Normalization of uClust and uCysB to urinary creatinine did not alter the results. No differences were observed in sCr and SDMA between the snake-envenomed group and the healthy control group. Spearman rank correlation analysis revealed a strong association of uClust with uCysB in the snake-envenomed dogs (r = 0.75 P < 0.001) but not in the healthy controls. The high percentage of snake-envenomed dogs with increased uClust and uCysB concentrations in the absence of increased sCr and SDMA suggests renal tubular injury in the affected dogs. Larger prospective case-controlled studies are warranted to evaluate the clinical utility and prognostic value of these biomarkers.

Ability of different assay platforms to measure renal biomarker concentrations during ischaemia-reperfusion acute kidney injury in dogs

Several protein biomarkers have been shown to be useful for the early diagnosis of acute kidney injury (AKI) in animals and people. Multiplex assays for measurement of a panel of renal biomarkers in canine samples have recently become available. This study compared the use of two such assays, versus previously validated ELISAs, to measure five biomarkers in canine samples during ischaemia-reperfusion (IR) AKI. Blood and urine was collected from six male anaesthetised greyhounds that underwent 1-h of renal ischaemia (severe hypotension induced by acute haemorrhage) and 2-h of reperfusion (intravenous fluid resuscitation). Histology confirmed presence of acute tubular injury at 2 h of reperfusion. Concentrations of clusterin, cystatin C, kidney-injury molecule 1 (KIM-1), monocyte chemoattractant protein 1, and neutrophil gelatinase-associated lipocalin (NGAL) at baseline and following IR, measured by two different multiplex assays and previously-validated single analyte immunoassays, were compared. Only NGAL was significantly elevated following IR with all assays investigated. Whether concentrations of the other four biomarkers were significantly increased following IR depended on the assay used. Concentrations of cystatin C and KIM-1 measured with the multiplex assays were of a vast magnitude lower than those measured with the corresponding single analyte ELISAs. We conclude that further validation is required before these assays can reliably be used to measure AKI biomarkers in canine samples.

Validation of a commercial magnetic bead-based multiplex assay for 5 novel biomarkers of acute kidney injury in canine serum

Interest is growing in measurement of novel biomarkers for the diagnosis of acute kidney injury. Multiplex assays may provide a rapid and cost-effective way of measurement; however, sparse information is published regarding their use in dogs. We aimed to validate a commercial magnetic bead-based assay for 5 biomarkers: clusterin (Clus), cystatin C (CysC), kidney injury molecule 1 (KIM-1), monocyte chemoattractant protein 1 (MCP-1), and neutrophil gelatinase-associated lipocalin (NGAL). Intra- and inter-assay imprecision, linearity under dilution (LUD), spike recovery (S-R), and hemoglobin interference were evaluated using serum from healthy and diseased dogs. Additionally, the effect of sample type (serum vs. plasma) was investigated. All values for Clus and MCP-1 were outside the assay's measurable range. Intra- and inter-assay precision were acceptable for NGAL (CVs 8.8% and 13.2%, respectively). Regression analysis of LUD and S-R indicated good linearity for CysC and NGAL. Hemolysis did not affect measurement of any biomarker. Measured concentrations of CysC (p = 0.018) and NGAL (p = 0.015) were significantly lower in sodium citrate plasma compared to serum. We conclude that this magnetic bead-based assay is precise and accurate for NGAL measurement in canine serum. Inappropriate standards for MCP-1 and Clus, and poor accuracy for KIM-1 measurement, suggest that this assay cannot reliably quantify those biomarkers in canine blood. Measurements of CysC in canine blood using this assay must be interpreted with caution given inter-assay imprecision.

Latest trends in L. infantum infection in dogs in Spain, Part II: current clinical management and control according to a national survey of veterinary practitioners

Background

Canine leishmaniosis (CanL) is a parasitic zoonotic disease, endemic in the Mediterranean basin including Spain. While knowledge about CanL, its management, treatment, prevention and control mounts, it remains unclear whether all clinical veterinarians follow the same international recommendations, such as those of the LeishVet group. This study was thus designed to assess recent trends in the clinical management of CanL in veterinary clinics across Spain through a questionnaire-based survey. Results were compared with those of a prior national multicenter questionnaire administered by our research team in 2005.

Methods

A questionnaire consisting of 28 questions about CanL was developed using Google Forms and distributed by email to 1428 veterinary clinics in Spain. Questions were designed to obtain data on common clinical signs, techniques and complementary exams used to diagnose the disease, and on its monitoring, treatment and control measures. Data were collected in a database for statistical analysis.

Results

Completed questionnaires were returned by 295 clinics. Compared to the situation in 2005, responses indicate that clinical signs of CanL have not changed significantly, cutaneous lesions being still the most prevalent sign observed by practitioners. Quantitative serological techniques are considered an adequate approach to diagnosis, provided their results are supported by the findings of a thorough physical exam, as well as complementary tests (complete blood count, biochemical profile, plasma protein electrophoretogram and complete urinalysis). Treatment protocols and check-ups follow international recommendations. Finally, a multimodal approach is being endorsed to adequately control CanL including preventive measures such as annual serological check-ups and the combination of repellents and vaccines. Additionally, owners are being better informed about CanL by veterinarians, which translates to the improved control of this zoonosis.

Conclusions

The clinical management of CanL has recently undergone significant changes owing to improvements in clinical knowledge of the disease, more unified international criteria, improved diagnostic techniques and their adequate interpretation, as well as a greater awareness of the disease transmitted to owners.

Measurements of echocardiographic indices and biomarkers of kidney injury in dogs with chronic kidney disease

Pathophysiological cardiac and renal interactions are termed cardiovascular-renal disorder (CvRD). Cardiovascular disease/dysfunction secondary to kidney disease (CvRD_K), is a leading cause of death in human chronic kidney disease (CKD) patients. The presence and clinical impact of CvRD_K in dogs with CKD is unknown. We hypothesized that echocardiographic measurements, and cardiac and renal biomarkers, will be altered in dogs with CKD and associated with survival. Eleven dogs with CKD (n = 6 IRIS stage 2, n = 5 IRIS stage 3) and without primary cardiac disease, plus 12 healthy age-matched control dogs, were recruited to this prospective observational study. Dogs underwent standard echocardiography, glomerular filtration rate (GFR) estimation by iohexol clearance, and measurement of plasma cardiac troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP), plasma and urinary cystatin B, and urinary clusterin and neutrophil gelatinase-associated lipocalin (NGAL). Values were compared between groups, and their association with all-cause mortality explored. Dogs with CKD had significantly lower GFR and higher NT-proBNP, urinary cystatin B, clusterin, and NGAL, compared to controls (P < 0.05). Echocardiographic measurements were similar between dogs with CKD and controls. Median follow-up time was 666 days, during which six dogs with CKD died. Risk of death was associated with increasing age, serum total protein, and normalized left ventricular posterior wall thickness (LVPWDN) and decreasing bodyweight and packed cell volume. Although baseline differences in echocardiographic measurements were not evident between dogs with moderate CKD and controls, the presence of CvRD_K was suggested by the association between LVPWDN and survival.

Proteomic Analysis of Urine from California Sea Lions ( Zalophus californianus): A Resource for Urinary Biomarker Discovery

Urinary markers for the assessment of kidney diseases in wild animals are limited, in part, due to the lack of urinary proteome data, especially for marine mammals. One of the most prevalent kidney diseases in marine mammals is caused by Leptospira interrogans, which is the second most common etiology linked to stranding of California sea lions ( Zalophus californianus). Urine proteins from 11 sea lions with leptospirosis kidney disease and eight sea lions without leptospirosis or kidney disease were analyzed using shotgun proteomics. In total, 2694 protein groups were identified, and 316 were differentially abundant between groups. Major urine proteins in sea lions were similar to major urine proteins in dogs and humans except for the preponderance of resistin, lysozyme C, and PDZ domain containing 1, which appear to be over-represented. Previously reported urine protein markers of kidney injury in humans and animals were also identified. Notably, neutrophil gelatinase-associated lipocalin, osteopontin, and epidermal fatty acid binding protein were elevated over 20-fold in the leptospirosis-infected sea lions. Consistent with leptospirosis infection in rodents, urinary proteins associated with the renin-angiotensin system were depressed, including neprilysin. This study represents a foundation from which to explore the clinical use of urinary protein markers in California sea lions.

Alisol A 24-Acetate and Alisol B 23-Acetate Induced Autophagy Mediates Apoptosis and Nephrotoxicity in Human Renal Proximal Tubular Cells

Two natural compounds alisol A 24-acetate (24A) and alisol B 23-acetate (23B) are abundant in Rhizoma alismatis. In the present study, we evaluated the induction of 24A and 23B on apoptosis and possible nephrotoxicity of human renal proximal tubular (HK-2) cells by activating autophagy and also explored its regulation on PI3K/Akt/mTOR signaling pathway. Presently, Clusterin, Kim-1, and TFF-3 were considered to be new bioindicators of nephrotoxicity. Interestingly, the protein expression and mRNA levels of Clusterin, Kim-1 and TFF-3 could be significantly increased by 23B and 24A in vivo and in vitro. Furthermore, cell apoptosis could be triggered by 23B and 24A via significantly decreasing the protein expression and mRNA levels of Bcl-2 and Bcl-xl. Autophagy of HK-2 cells could be induced by both 23B and 24A via significantly enhancing the ratio of LC3II/LC3I, the protein expression of Beclin-1 as well as the mRNA levels of LC3 and Beclin-1. Meanwhile, PI3K/Akt/mTOR signaling pathway could be inhibited by these two compounds. An autophagy inhibitor, 3-methyladenine, could partially reverse cell viability and conversely change the ratio of LC3II/LC3I and the protein expression of Bcl-2 and Kim-1. Thus this study helped to understand that 23B and 24A induced autophagy resulted in apoptosis and nephrotoxicity through inhibiting PI3K/Akt/mTOR signaling pathway, facilitating further studies for nephrotoxicity induced by these two compounds and could be beneficial for safe use of Rhizoma alismatis in clinic.

Laboratory tests for diagnosing and monitoring canine leishmaniasis

Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (increased acute phase proteins [APP] or α₂ - and/or γ-globulins). Although a potential gammopathy is usually polyclonal, it may also appear oligo- or monoclonal, especially in dogs coinfected by other vector-borne pathogens. When lesions are accessible to fine-needle aspiration (lymphoadenomegaly, nodular lesions, joint swelling), cytology is strongly advised, as the presence of Leishmania amastigotes in a pattern of pyogranulomatous inflammation or lymphoplasmacytic hyperplasia is diagnostic. If the cytologic pattern is inconclusive, the parasite should be identified by histology/immunohistochemistry or PCR on surgical biopsies. Alternatively, cytology and PCR may be performed on bone marrow samples where amastigotes, along with erythroid hypoplasia, myeloid hyperplasia, plasmacytosis, or secondary dysmyelopoiesis can be observed. Dogs with overt leishmaniasis generally have high antibody titers, while low titers predominate in immunologically resistant infected dogs or in exposed dogs with no parasite confirmation. Quantitative serology is recommended in clinically suspect dogs as high-titer antibodies titers may confirm the clinical diagnosis. In confirmed and treated dogs, renal function and inflammatory/immune response variables should be periodically monitored.

Changes in serum biomarkers of oxidative stress after treatment for canine leishmaniosis in sick dogs

Canine leishmaniosis (CanL) is a zoonotic disease being endemic in several parts of the world. In this study we investigated the behavior of a panel of biomarkers of oxidative stress in 12 sick dogs naturally infected by CanL before and at days 30 and 180 of a successful therapy with a standard treatment. The assays total oxidant status (TOS), trolox equivalent antioxidant capacity (TEAC), ferric reducing ability of plasma (FRAP), cupric reducing antioxidant capacity (CUPRAC), serum thiol and paraoxonase 1 (PON1) were included in the panel. In addition, correlations between biomarkers of oxidative stress and inflammation (C-reactive protein (CRP) and ferritin) and urinary protein:creatinine ratio (UPC) were calculated. Serum CUPRAC, thiol and PON1 significantly increased after treatment and were negatively correlated with CRP, ferritin and UPC. This study demonstrates that biomarkers of oxidative stress, not previously studied in leishmaniosis such as CUPRAC and thiol, can change after a successful treatment for CanL showing a potential for use in monitoring the treatment of this disease.

A mixed grape and blueberry extract is safe for dogs to consume

Background

Grape and blueberry extracts are known to protect against age-related cognitive decline. However, beneficial effects achieved by mixing grape and blueberry extracts have yet to be evaluated in dogs, or their bioavailability assessed. Of concern to us were cases of acute renal failure in dogs, after their ingestion of grapes or raisins. The European Pet Food Industry Federation (2013) considers only the grape or raisin itself to be potentially dangerous; grape-seed extracts per-se, are not considered to be a threat. Our aim was therefore to evaluate the renal and hepatic safety, and measure plasma derivatives of a polyphenol-rich extract from grape and blueberry (PEGB; from the Neurophenols Consortium) in dogs. Polyphenol expression was analyzed by UHPLC-MS/MS over 8 hours, for dogs given PEGB at 4 mg/kg. Safety was evaluated using four groups of 6 dogs. These groups received capsules containing no PEGB (control), or PEGB at 4, 20, or 40 mg/kg BW/d, for 24 weeks. Blood and urine samples were taken the week prior to study commencement, then at the end of the 24-wk study period. Routine markers of renal and liver damage, including creatinine (Creat), blood urea nitrogen, albumin, minerals, alkaline phosphatase (ALP), and alanine transaminase (ALT) were measured. Biomarkers for early renal damage were also evaluated in plasma (cystatin C (CysC), and neutrophil gelatinase-associated lipocalin (NGAL)), and urine (CysC, clusterin (Clu), and NGAL). Ratios of urinary biomarkers to Creat were calculated, and compared with acceptable maximal values obtained for healthy dogs, as reported in the literature.

Results

While several PEGB-specific polyphenols and metabolites were detected in dog plasma, at the end of the PEGB consumption period, our biomarker analyses presented no evidence of either renal or liver damage (Creat, BUN, ionogram, albumin and ALT, ALP). Similarly, no indication of early renal damage could be detected. Plasma CysC, urinary CysC/Creat, Clu/Creat, and NGAL/Creat ratios were all beneath reported benchmarked maximums, with no evidence of PEGB toxicity.

Conclusions

Long-term consumption of a pet specific blend of a polyphenol-rich extract from grape and blueberry (PEGB; from the Neurophenols Consortium), was not associated with renal or hepatic injury, and can therefore be considered safe.

Kidney Disease and the Nexus of Chronic Kidney Disease and Acute Kidney Injury: The Role of Novel Biomarkers as Early and Accurate Diagnostics

Chronic kidney disease (CKD) and acute kidney injury (AKI) are interconnected and the presence of one is a risk for the other. CKD is an important predictor of AKI after exposure to nephrotoxic drugs or major surgery, whereas persistent or repetitive injury could result in the progression of CKD. This brings new perspectives to the diagnosis and monitoring of kidney diseases highlighting the need for a panel of kidney-specific biomarkers that reflect functional as well as structural damage and recovery, predict potential risk and provide prognosis. This article discusses the kidney-specific biomarkers, symmetric dimethylarginine (SDMA), clusterin, cystatin B, and inosine.

Cisplatin nephrotoxicity in male beagle dogs: next-generation protein kidney safety biomarker tissue expression and related changes in urine

This 10-day (D) study was conducted to evaluate changes in traditional and newer kidney safety biomarker expression levels in dogs. Animals received cisplatin (CDDP, 0.75 mg per kg per day) or 0.9% Saline (vehicle) for 5 days. Serum/urine samples were collected at various time points. Cage-side observations included emesis (D1-2/D4-D5/D7-9), absence of stool (D5-9/D11), soft stool (D4-7/D12), excessive salivation (D1/D3/D5-6), decreased food consumption (D5-8), decreased activity (D7-8) and/or dehydration (D7). Animals were necropsied when serum creatinine (sCr) levels measured at ≥1.9 mg dL^-1, indicating significant loss of renal function; or at the end of the study (D11). When compared to controls, increases in BUN/sCr were detected on D3, D5 and/or D8. Increases in urinary total protein (Ur TP) were noted on D6. The moribund dog that was euthanized early on D7 showed insignificant increases in urinary osteopontin (Ur OPN), urinary neutrophil gelatinase-associated lipocalin (Ur NGAL), urinary clusterin (Ur CLU), sCr, serum cystatin C (sCYS C) and urinary cystatin C (Ur CYS C) on D5 when compared to controls. Insignificant increases in urinary albumin (Ur ALB) were observed from an animal that was euthanized on D7 and 1 : 2 surviving animals on D8 relative to baseline. From three dogs that were euthanized on D9, increases in Ur CLU, and/or sCYS C were noted on D8 relative to baseline. The two surviving dogs showed elevated Ur CLU and 1 : 2 surviving dogs showed elevated Ur CYS C. Decreased urinary kidney injury molecule 1 (Ur KIM-1) on D3/D5 was evident (versus baseline and controls). CDDP-induced cortico-medullary lesions were characterized as minimal to mild tubule degeneration/necrosis, dilatation, regeneration, cell alteration, intratubular casts, interstitial inflammation and vacuolization. Increased Ur OPN and Ur CLU correlated with enhanced OPN and CLU immunopositive staining in damaged cortical epithelium in the proximal tubules. Enhanced KIM-1 staining in damaged cortico-medullary tubular epithelium appeared in the absence of rises in Ur KIM-1. This study showed changes in kidney safety protein biomarkers associated with CDDP nephrotoxicity in dogs and possibly in humans.

Urinary ferritin and cystatin C concentrations at different stages of kidney disease in leishmaniotic dogs

Traditional analytes do not detect early renal disease; therefore there is a need to find new early markers of chronic kidney disease (CKD) in dogs to avoid the progression to irreversible renal damage. Our objective was to evaluate the presence of ferritin and cystatin C in urine of dogs with CKD and to relate their concentrations with the severity of the disease. Samples obtained from dogs naturally infected with Leishmania infantum were classified into four groups on the basis of the results of urinary protein/creatinine ratio and serum creatinine. This study shows that ferritin and cystatin C concentrations were increased in the urine of dogs with renal damage. Cystatin C value in urine only increased in severe stages of CKD with serum creatinine values >1.4 mg/dL, while the urinary ferritin concentration increased in dogs with proteinuria and serum creatinine <1.4 mg/dL, being, therefore, a renal biomarker earlier than creatinemia.

Ligustrazine attenuates elevated levels of indoxyl sulfate, kidney injury molecule-1 and clusterin in rats exposed to cadmium

In this study, we aimed at evaluating the effect of ligustrazine, a major constituent of Ligusticum wallichii from traditional Chinese medicine, on Cd-induced changes in nephrotoxicity indices. Rats were divided into four experimental groups: control; ligustrazine; Cd and ligustrazine+Cd. Cd treated alone group showed significant decreases (P<0.05) in body weight, renal levels of superoxide dismutase (SOD) and glutathione reductase (GR); and significant increases (P<0.05) in urine volume (24h), pH values, serum blood urea nitrogen (BUN), serum uric acid, kidney malondialdehyde (MDA), urinary total protein, urinary glucose, urinary lactate dehydrogenase (LDH) and urinary alkaline phosphatase (ALP). Apart from indoxyl sulfate (a uremic toxin), two newly accepted nephrotoxicity biomarkers including kidney injury molecule-1 (kim-1) and clusterin were also found to be increased. Nonetheless, all these effects induced by Cd were reversed upon treatment by ligustrazine although it failed in decreasing the concentrations of Cd in kidney and urine. Histopathological studies in Cd-treated rats exhibited renal tubule damage, which was also ameliorated by ligustrazine pretreatment. These results suggest that ligustrazine exhibits protective effects on Cd-induced nephrotoxicity. Additionally, this study also demonstrates Cd exposure induces elevated levels of indoxyl sulfate in serum and kidney, and clusterin in urine.