Urine neutrophil gelatinase-associated lipocalin to diagnose and characterize acute kidney injury in dogs

Urinary neutrophil gelatinase-associated lipocalin as early biomarker for renal disease in dogs with leishmaniosis

Canine leishmaniosis (CanL), caused by Leishmania sp., presents a wide array of symptoms; renal dysfunction is frequently observed in these dogs and is associated with a poor prognosis and increased mortality. The traditional biomarkers namely urea and creatinine can detect renal damage but only in advanced stages of the disease. However, it has been shown that the symmetric dimethylarginine assay (SDMA) or the protein/creatinine ratio (UPC) and are early biomarkers of renal dysfunction. Their elevation occurs earlier than that of creatinine, but other novel biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) are currently under investigation. Our objective was to determine whether the urine NGAL-creatinine ratio (uNGAL/c) can provide very early diagnosis of kidney disease in CanL. In total, 68 dogs were included in the study: 15 healthy dogs and 53 dogs with CanL who were classified according to International Renal Interest Society (IRIS) classification: IRIS 1 (N= 34), IRIS 2 (N= 9) and IRIS 3/4 (N= 10). IRIS 1 was subdivided according to proteinuria in IRIS 1NP (13 dogs with UPC < 0.2), IRIS 1BL (8 dogs with UPC = 0.2-0.5) and IRIS 1 P (13 dogs with UPC > 0.5). Blood samples were collected for complete hematological and biochemistry analysis including plasma NGAL. Urinalysis included specific gravity, UPC, CysC and NGAL expressed as a ratio with creatinine. The mean concentrations of pCysC and SDMA in CanL, show a statistically significant increase from IRIS 1NP, not being statistically significant for pCysC in the IRIS 1BL group. The UPC show a statistically significant increase from IRIS 1NP. In all groups with CanL for uCysC/c and uNGAL/c was observed a statistically significant increase. The uNGAL/c in the group proteinuric animals, presents a positive correlation with all renal biomarkers studied. In the group of non-proteinuric animals, the uNGAL/c presents a positive correlation with SDMA and UPC. The uNGAL/c can be considered a reliable indicator of renal disease in dogs diagnosed with CanL who are non-azotemic and non-proteinuric.

Assessment of cell cycle arrest biomarkers and neutrophil gelatinase-associated lipocalin to distinguish acute kidney injury from other diseases in dogs

BACKGROUND

Cell cycle arrest biomarkers (tissue inhibitor of metalloproteinase-2 [uTIMP-2] and insulin-like growth factor binding protein 7 [uIGFBP7]), and neutrophil gelatinase-associated lipocalin (NGAL) variables are valuable biomarkers for early diagnosis of acute kidney injury (AKI) in people.

OBJECTIVES

To evaluate uTIMP-2, uIGFBP7, fractional excretion of NGAL (FeNGAL), and urinary to serum NGAL ratio (u/sNGAL) in healthy dogs, dogs with AKI, dogs with chronic kidney disease (CKD), and critically ill (CI) dogs.

ANIMALS

Forty-two client-owned dogs (healthy, n = 10; AKI, n = 11; CKD, n = 11; CI, n = 10).

METHODS

Prospective, observational study. After assessment of routine renal biomarkers, stress (uTIMP-2, uIGFBP7) and damage (NGAL) biomarkers were measured, using ELISA kits, and normalized to urinary creatinine (uCr).

RESULTS

Normalized uTIMP-2 and [uTIMP-2] × [uIGFBP7]/uCr were significantly higher in the AKI group (median 151.9 [range, 2.2-534.2] and 62.9 [1.1-266.8] pg/mL respectively), compared to healthy dogs (0.3 [0.2-74.7]; P < .001 and 0.16 [0.1-58.1] pg/mL; P < .001), dogs with CKD (0.7 [0.3-742.5]; P = .04 and 0.37 [0.2-180.1] pg/mL; P = .03) and CI dogs (1.9 [0.2-37.0]; P = .03 and 0.8 [0.1-16.1] pg/mL; P = .02). Fractional excretion of NGAL was significantly higher in dogs with AKI (54.17 [7.93-155.32] %), than in healthy (0.03 [0.01-0.21] %; P < .001) and CI dogs (3.05 [0.05-28.86] %; P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Normalized uTIMP-2, [uTIMP-2] × [uIGFBP7]/uCr, and FeNGAL can be valuable renal biomarkers for early diagnosis of AKI in dogs.

Diagnostic efficacy of urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 for early detection of acute kidney injury in dogs with leptospirosis or babesiosis

This study evaluates the diagnostic efficacy of urinary biomarkers, Neutrophil Gelatinase-Associated Lipocalin (uNGAL), and Kidney Injury Molecule-1 (uKIM-1), in identifying Acute Kidney Injury (AKI) in dogs affected with leptospirosis or babesiosis. Acute kidney injury was diagnosed based on the increase in serum creatinine levels above 0.3 mg/dL within 48 h and dogs were categorized according to AKI grades based on International Renal Interest Society guidelines. Traditional biomarkers (serum creatinine and blood urea nitrogen) and novel biomarkers like urinary NGAL and urinary KIM-1 levels were measured and compared to concentrations obtained in control dogs. Statistical analysis assessed significant differences (P < 0.01) across AKI grades, specifically noting elevated urinary NGAL and KIM-1 in IRIS grade I AKI (P < 0.001). The study highlights the diagnostic significance of urinary NGAL and KIM-1 as early indicators of renal damage, particularly valuable in non-azotemic AKI cases, offering promising markers for early AKI diagnosis in veterinary clinical settings. These biomarkers demonstrate clinical utility and underscore their potential for improving AKI management in veterinary medicine. Further validation studies involving larger cohorts and diverse etiologies of AKI are needed to confirm the diagnostic accuracy and clinical utility of urinary NGAL and KIM-1 in veterinary practice.

Cysteine as an Innovative Biomarker for Kidney Injury

BACKGROUND

Kidney transplantation is a widely used treatment for end-stage kidney disease. Nevertheless, the incidence of acute kidney injury (AKI) in deceased donors poses a potential hazard because it significantly increases the risk of delayed graft function and potentially exerts an influence on the kidney allograft outcome. It is crucial to develop a diagnostic model capable of assessing the existence and severity of AKI in renal grafts. However, no suitable kidney injury markers have been developed thus far.

METHODS

We evaluated the efficacy of the molecular probe NPO-B, which selectively responds to cysteine, as a new diagnostic tool for kidney injury. We used an in vitro model using ischemia/reperfusion injury human kidney-2 cells and an in vivo ischemia/reperfusion injury mouse model. Additionally, cysteine was investigated using urine samples from deceased donors and living donors to assess the applicability of detection techniques to humans.

RESULTS

This study confirmed that the NPO-B probe effectively identified and visualized the severity of kidney injury by detecting cysteine in both in vitro and in vivo models. We observed that the fluorescence intensity of urine samples measured using NPO-B from the deceased donors who are at a high risk of renal injury was significantly stronger than that of the living donors.

CONCLUSIONS

If implemented in clinical practice, this new diagnostic tool using NPO-B can potentially enhance the success rate of kidney transplantation by accurately determining the extent of AKI in renal grafts.

Association between echocardiographic indexes and urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in dogs with myxomatous mitral valve disease

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of tubular damage, and its elevation has been described in human and canine cardiorenal syndrome. The aim was to evaluate the association between echocardiographic indexes and urine NGAL (uNGAL) and uNGAL normalized to urine creatinine (uNGALC) in dogs with MMVD. This is a multicentric prospective cross-sectional study. A total of 77 dogs with MMVD at different ACVIM stages were included. All dogs underwent echocardiography, serum chemistry, and urinalysis. Echocardiographic data analyzed were shortening fraction (SF), left ventricular diastolic (LVIDDn) and systolic (LVIDSn) diameters normalized for body weight, left atrium to aortic root ratio (LA/Ao), maximal (LAVMax) and minimal (LAVMin) left atrial volumes, LA stroke volume (LASV), early diastolic mitral peak velocity (EVmax), EVmax to tissue Doppler E' wave (E/E'), aortic (VTIAo) and mitralic (VTIMit) velocity time integrals and their ratio (VTIMit/VTIAo), and tricuspid regurgitation velocity (TRVmax). In the univariate analysis LASV, TRVmax, LAVMax, LVIDDn, and VTIMit/VTIAo were independent predictors of increased uNGAL and uNGALC; however, only LASV [(OR: 1.96, 95% CI: 1.16 to 3.31) P = 0.01 for NGAL, and (OR: 2.79, 95% CI: 1.50 to 5.17) P < 0.001 for NGALC] and TRVmax [(OR: 1.73, 95% CI: 1.20-2.51) P = 0.002 for NGAL, and (OR: 1.50, 95% CI: 10.07-2.10) P = 0.015 for NGALC] remained statistically significant in the multivariable analysis. Based on our results, LASV and TRVmax are associated with increased uNGAL and uNGALC. These parameters might detect dogs with MMVD at higher risk of developing kidney damage.

A Pilot Study of the Role of Selected Biomarkers of Kidney Injury in Dogs with Dilated Cardiomyopathy

Heart and kidney diseases are among the most frequent medical conditions diagnosed in small animals. Due to the functional interconnection between these organs, the concept of the cardio-renal axis has been developed. In this context, renal disease or dysfunction often occurs secondary to heart diseases, such as dilated cardiomyopathy (DCM). DCM is the most common cardiomyopathy and a leading cause of mortality in large-breed dogs. Traditional biomarkers like creatinine or symmetric dimethylarginine concentration are not always effective, especially in the early stages of the disease, underscoring the need for more sensitive markers of renal impairment during heart failure (HF). This study aimed to evaluate the efficacy of selected biomarkers as indicators for early kidney damage in dogs with stage B2 DCM. We measured serum concentrations of cystatin C, KIM-1 (kidney injury molecule-1), and NGAL (neutrophil gelatinase-associated lipocalin) and their ratios to creatinine, analyzing their diagnostic values. Cystatin C was quantified using a sandwich enzyme immunoassay, while KIM-1 and NGAL were measured with enzyme-linked immunosorbent assay kits designed for canine diagnostics. The concentrations were indexed against serum creatinine. The study included 26 dogs: 9 with HF and 17 healthy controls. The mean ± standard deviation for healthy dogs for cystatin C, cystatin C/creatinine ratio, KIM-1, KIM-1/creatinine ratio, NGAL, and NGAL/creatinine ratio were 0.24 ± 0.04, 0.26 ± 0.07, 0.61 ± 0.07, 0.67 ± 0.13, 2.76 ± 1.8, and 2.79 ± 1.81, respectively. For DCM dogs, these values were 0.27 ± 0.1, 0.32 ± 0.12, 0.61 ± 0.08, 0.69 ± 0.17, 6.46 ± 5.22 (p = 0.02), and 7.99 ± 6.53 (p = 0.04). This study's findings suggest that during the asymptomatic phase of DCM, only NGAL concentration and the NGAL/creatinine ratio may serve as diagnostic markers for early-stage kidney injury.

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.

Concentrations and kinetics of renal biomarkers in dogs with gastric dilatation-volvulus with and without 24-h intravenous lidocaine

Background

Gastric dilatation volvulus (GDV) can lead to organ failure including acute kidney injury (AKI). Due to its cytoprotective, antioxidant and anti-inflammatory effects, lidocaine has a potential to prevent AKI in dogs with GDV.

Design and setting

Prospective, observational cohort study in client-owned dogs with GDV.

Objective

To determine concentrations of renal biomarkers for AKI in dogs with GDV with and without intravenous (IV) lidocaine therapy.

Methods

Thirty-two dogs were randomized to receive either IV lidocaine (2 mg/kg, followed by a lidocaine constant rate infusion at a dose of 50 μg/kg/min over 24 h; n = 17) or no lidocaine (n = 15). Blood and urine samples were taken at admission (T 0) (only blood), during or immediately after surgery (T 1), and 24 (T 24) and 48 (T 48) h after surgery. Plasma creatinine (pCr), plasma neutrophil gelatinase-associated lipocalin (pNGAL), urinary NGAL (uNGAL), uNGAL to creatinine ratio (UNCR), and urinary gamma-glutamyl transferase to creatinine ratio (uGGT/uCr) were evaluated. Biomarker concentrations were compared between dogs with and without IV lidocaine and the course of each marker was determined in comparison to its admission value.

Results

In the entire population, a significantly higher pCr at T 0 (median, 95 μmol/L, interquartile range, 82-105) compared with T 1 (69 μmol/L, 60-78), T 24 (63 μmol/L, 52-78), and T 48 (78 μmol/L, 65-87) (P < 0.001) was found. Plasma NGAL increased significantly between T 0 (5.66 ng/mL, 3.58-7.43) and T 24 (7.50 ng/mL, 4.01-11.89) (P = 0.006) and T 48 (9.86 ng/mL, 5.52-13.92) (P < 0.001), respectively. Urinary NGAL increased significantly between T 1 (0.61 ng/mL, 0.30-2.59) and T 24 (2.62 ng/mL, 1.86-10.92) (P = 0.001) and T 48 (4.79 ng/mL, 1.96-34.97 (P < 0.001), respectively. UNCR increased significantly between T 1 (0.15 μg/mmol, 0.09-0.54) and T 24 (1.14 μg/mmol, 0.41-3.58) (P = 0.0015) and T 48 (1.34 μg/mmol, 0.30-7.42) (P < 0.001), respectively. Concentrations of uGGT/uCr increased significantly from T 0 highest at T 24 (6.20 U/mmol, 3.90-9.90) and significantly decreased at T 48 (3.76 U/mmol, 2.84-6.22) (P < 0.001). No significant differences in any renal biomarker concentration were found between dogs with and without IV lidocaine therapy.

Conclusion and clinical relevance

Plasma NGAL, uNGAL and UNCR remained increased up to 48 h post-surgery. No evidence of lidocaine-associated renoprotection was found.

Evaluation of urinary neutrophil gelatinase-associated lipocalin to detect renal tubular damage in dogs with stable myxomatous mitral valve disease

BACKGROUND

Dogs with myxomatous mitral valve disease (MMVD) can experience progressive renal tubular damage and dysfunction. The prevalence of renal tubular damage is not known in dogs with stable MMVD.

OBJECTIVE

To evaluate renal tubular damage in dogs with stable MMVD by evaluation of urinary neutrophil gelatinase-associated lipocalin (NGAL).

ANIMALS

Ninety-eight MMVD dogs grouped according to the American College of Veterinary Internal Medicine (ACVIM) staging (group B1, n = 23; group B2, n = 27; group C + D, n = 48) and 46 healthy dogs.

METHODS

Multicenter prospective observational study. Serum and urine chemistry including NGAL reported as uNGAL concentration (uNGAL) and normalized with urinary creatinine (uNGALC) were compared between MMVD dogs and healthy controls, and among different MMVD ACVIM stages.

RESULTS

The MMVD dogs had significantly higher uNGAL and uNGALC (1204 pg/mL; range, 30-39 732 and 1816 pg/mg; range, 22-127 693, respectively) compared to healthy dogs (584 pg/mL; range, 56-4072 and 231 pg/mg; range, 15-2407, respectively; P = .002 and P < .0001, respectively). Both uNGAL and uNGALC increased with the increasing ACVIM stage (P = .001 and P < .001, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Renal tubular damage is present in dogs with stable MMVD, as measured by increased uNGAL. This tubular damage is subclinical, occurs in all stages of MMVD even in the absence of azotemia, and increases with the severity of MMVD. Reno-protective approaches to manage MMVD dogs should be explored to slow the progression of renal tubular damage in these patients.

Biomarkers of Kidney Disease in Horses: A Review of the Current Literature

Creatinine only allows detection of kidney disease when 60 to 75% of the glomerular function is lost and is therefore not an ideal marker of disease. Additional biomarkers could be beneficial to assess kidney function and disease. The objectives are to describe new equine kidney biomarkers. This systematic review assesses the available literature, including the validation process and reference values, following which the authors suggest recommendations for clinical use. SDMA may have some potential as equine kidney biomarker, but there is currently a lack of evidence that SDMA offers any advantage compared to creatinine in detecting Acute Kidney Injury (AKI). Cystatin C and podocin show potential as biomarkers for kidney disease (including detecting AKI earlier than creatinine) and should be studied further. NGAL has potential as a biomarker of kidney disease (including detecting AKI earlier than creatinine), and potential as an inflammatory marker. Literature on MMP-9 does not allow for conclusive statements about its potential as a biomarker for kidney disease. The future may show that NAG has potential. For all biomarkers, at this stage, available scientific information is limited or too scarce to support clinical use, and only SDMA can be measured for clinical purposes. In conclusion, there are multiple new biomarkers with the potential to diagnose kidney problems. However, there are only a few studies available and more data is needed before these biomarkers can be applied and recommended in our daily practice.

Effect of an Immunomodulatory Feed Additive in Mitigating the Stress Responses in Lactating Dairy Cows to a High Concentrate Diet Challenge

Dairy cows are often exposed to multiple stressors in a lactation-cycle, with sub-acute ruminal acidosis (SARA) a frequent example of nutritional stress. SARA affects ruminal and intestinal equilibrium resulting in dysbiosis with localized and systemic inflammation impacting animal health and productivity. OmniGen-AF (OMN, Phibro Animal Health Corporation, Teaneck, NJ, USA) is a feed product recognized for modulating innate immune function, especially during periods of stress. The objective of this study was to determine the effects of OMN in lactating dairy cows fed a high-starch, low-fiber diet. Twenty-four blocked cows were assigned to control or treatment (55 g/d). After the additive adaptation (49 d) cows were fed the challenge diet (28 d). Milk, rumination and pH were continuously recorded; components, rumen fluid, and blood were taken in multiple time-point and analyzed. Results showed that the challenge decreased the rumination, shifted ruminal fluid composition, decreased milk production and the components, and slightly increased the time below pH 5.5, with no differences between groups. The treatment produced greater rumen butyrate and lower lactate, prompter regeneration of red blood cells, increase of neutrophils, lower paraoxonase, gamma-glutamyl-transferase, and β-hydroxybutyrate, with no differences on other tested inflammatory markers. Results show that OMN helps modulating some of the metabolic and immunological responses to SARA.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS AND RELEVANCE

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

Evaluation of symmetric dimethylarginine and Doppler ultrasonography in the diagnosis of gentamicin-induced acute kidney injury in dogs

Acute kidney injury is a common problem in dogs and is associated with significant morbidity and mortality. So, the present study aimed to evaluate symmetric dimethylarginine (SDMA) and Doppler ultrasonography including resistive index (RI) in the diagnosis of acute kidney injury in dogs. Ten healthy mongrel dogs were injected with gentamicin sulfate 10% at the dose of 30 mg/kg body weight daily for 10 days for induction of acute kidney injury. Clinical, biochemical, ultrasonographic, and Doppler ultrasonographic examinations and urinalysis were performed for all dogs on 0 day before induction, on the 5th day, and on the 10th day of induction. The results of the current study showed significant increase in plasma level of SDMA, serum urea, creatinine, phosphorus, and potassium and a significant decrease in serum sodium, calcium, and chloride on the 5th day and 10th day of induction, and there was an increase in renal cortical echogenicity of the right and left kidney compared to adjacent liver and spleen, respectively. RI value showed a significant increase on the 5th day and 10th day of induction. The present study showed that SDMA is a sensitive and promising biomarker for diagnosis of acute kidney injury in dogs compared to routine biomarkers; also, the RI of Doppler ultrasonography is useful for early identifying acute kidney injury when the only observable change is an increase in cortical echogenicity.

Immune-metabolic-inflammatory markers in Holstein cows exposed to a nutritional and environmental stressing challenge

Dairy cows are exposed to multiple stressors during the productive cycle, such as metabolic challenges, overcrowding, grouping change, environmental stress and dietary errors. Thus, it is essential to study reliable markers able to detect stress conditions in dairy farms. This study evaluates dairy cows' immunologic and metabolic markers after the sudden and combined exposition to a high-grain diet (75% concentrates) and the abrupt change of the housing system (from free stall to tie stall). A group of twenty-four Holstein cows were enrolled in a challenge study of 28 days duration. Several immunological and metabolic blood markers were evaluated over the trial. Blood samples were taken at day 0 (normal value) and day 1, 3, 7, 14, 21, and 28 (challenge). Data were submitted to a mixed model for repeated measures, including time as fixed and cows as random effects. The nutritional and environmental challenge had heavy effects on animal welfare and cows responded with a dramatic rumination drop. Our results suggest that the most responsive markers after abiotic stressors in cows were as follows: Serum Amyloid A and ROM in the acute response; Ceruloplasmin and GGT in the mid acute and Albumin, Paroxonase and FRAP in the chronic phase. Serum Amyloid A, Ceruloplasmin, Paraoxonase, GGT and ROM resulted as positive phase proteins, while, Albumin and FRAP resulted as negative phase proteins. Preliminary obtained results could concur to develop strategies able to mitigate stressor effects; moreover, the proposed design can be used as a model to test stress nutritional modulators.

Stage 1-Biomarkers of Kidney Injury in Dogs Undergoing Constant Rate Infusion of Hydroxyethyl Starch 130/0.4

In veterinary medicine, investigations relating the effects of hydroxyethyl starch (HES) on renal function report contrasting results. This study aimed to assess the changes in the selected biomarkers of kidney injury in dogs after the administration of HES 130/0.4 as a constant rate infusion (CRI) for 24 h. Ten adult client-owned dogs with hypoalbuminemia (albumin < 2 g/dL) and ongoing fluid losses were included. Enrolled dogs received intravenous fluid therapy with crystalloids and a CRI of HES 130/0.4 at a dose of 2 mL/kg/h for 24 h. Serum creatinine (sCr), fractional excretion (FE) of electrolytes, urinary protein to creatinine ratio (UPC), urinary albumin to creatinine ratio (UAC), SDS-page, and urinary neutrophil gelatinase-associated lipocalin (uNGAL) were measured at the baseline before HES infusion, and after 24 h (T24) and 48 h (T48) from the baseline. No statistically significant difference was found between the baseline value vs. T24 and the baseline vs. T48 for sCr, UAC, UPC, FE of sodium, chloride and calcium, and uNGAL. A significant increase in FEK (p = 0.04) was noticed between the baseline and T48. In this study sample of hypoalbuminemic dogs, HES 130/0.4 at the dose and rate of infusion applied did not cause any significant changes in the investigated biomarkers of kidney injury.

A longitudinal study of the persistence of increased creatinine and concordance between kidney biomarkers in cats and dogs

Kidney disease causes morbidity and mortality in dogs and cats. Serum creatinine concentration is an important surrogate marker for glomerular filtration rate (GFR). However, it is not always sensitive to small decreases in kidney function. Efforts to identify additional, more sensitive surrogate markers of GFR to improve detection of early kidney disease has led to the use of symmetrical dimethylarginine (SDMA) in veterinary medicine. There is insufficient information about the behavior of creatinine after an increase and the expected behavior of creatinine and SDMA in these cats and dogs. This study assesses the probability of persistence of increases in creatinine and the subsequent behavior of creatinine and SDMA in animals with persistently increased creatinine. For enrollment, three paired SDMA and creatinine concentrations were required: baseline (T0) with creatinine and SDMA at or below the upper reference limit (URL), T1, and T2 0.5-18 months after T1. The study included 4517 cats and 4576 dogs with increased T1 creatinine concentrations and 54,295 cats and 125,403 dogs with T1 creatinine at or below the URL. The probability of a persistently increased creatinine at T2 was approximately 58% for cats and 49% for dogs after a T1 increase. For animals without a T1 increase the probability of increased creatinine at T2 was only 7% for cats and 3% for dogs. For cats and dogs with persistently increased Cr, the probability of an increased SDMA concentration at T1 was 70-75%. By 24 months, that probability rose to 94% for cats and 88% for dogs.

Serial serum creatinine, SDMA and urinary acute kidney injury biomarker measurements in dogs envenomated by the European adder (Vipera berus)

Background

Acute kidney injury (AKI) is associated with high morbidity and mortality in dogs, but diagnosis may be impaired due the insensitivity of routine renal function biomarkers to detect earlier or milder forms of injury. Snake envenomation is one of several causes of AKI in dogs and humans. Dogs are commonly envenomated by the European adder (Vipera berus) between April and October each year, but few studies exist examining serial serum creatinine (sCr) and symmetric dimethylarginine (SDMA) measurements and AKI biomarkers in these dogs. Novel urinary biomarkers could improve clinical outcome by allowing earlier diagnosis of and intervention in AKI. The aim of this study was to assess the presence of AKI in dogs envenomated by V. berus at 12, 24 and 36 h after bite, as well as 14 days later, using sCr, SDMA and a panel of urinary AKI biomarkers normalised to urine creatinine (uCr), compared to a group of healthy control dogs.

Results

Thirty-five envenomated dogs and 35 control dogs were included. Serum creatinine did not exceed the upper reference limit at any time point in any dog after envenomation. Serum SDMA did not exceed 0.89 μmol/L in any dog. Compared to controls, urinary albumin/uCr, neutrophil gelatinase-associated lipocalin/uCr and monocyte chemotactic protein-1/uCr were significantly elevated 12 h (P <  0.0001, P <  0.0001, P = 0.01), 24 h (P <  0.001, P <  0.001, P = 0.002) and 36 h (P <  0.001, P <  0.001, P = 0.0008) after bite. Osteopontin/uCr was higher 24 and 36 h after bite (P < 0.0001), kidney injury molecule-1/uCr, interleukin-8/uCr and γ- glutamyl transferase/uCr were significantly higher 36 h after bite (P = 0.003, P = 0.0005, P = 0.001). Urinary cystatin C/uCr was not significantly different to controls at any timepoint. Biomarker/uCr ratios were not significantly different 14 days after envenomation compared to controls.

Conclusion

Urinary biomarker/Cr ratios are indicative of mild transient, non-azotaemic AKI in dogs envenomated by V. berus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02851-8.

Comparison of clinicopathological patterns of renal tubular damage in dogs with acute kidney injury caused by leptospirosis and other aetiologies

In humans, leptospiral acute kidney injury (AKI) is characterised by tubulointerstitial involvement and renal electrolyte losses, impacting clinical presentation and case management. The aim of this study was to evaluate urine chemistry findings in dogs with leptospirosis in order to identify characteristic patterns of tubular damage associated with this disease. Dogs with intrinsic AKI caused by leptospirosis and by other aetiologies were prospectively enrolled. Clinical and clinicopathological variables, including serum and urine chemistry, fractional excretion (FE%) of electrolytes, and urinary neutrophil gelatinase-associated lipocalin (NGAL), were evaluated in both groups and compared statistically. Dogs with leptospirosis (n = 38) had significantly higher serum creatinine concentration than dogs with AKI caused by other aetiologies (n = 37). Serum potassium and glucose concentrations were comparable between groups. Dogs with leptospiral AKI had significantly higher FE of potassium (median 100%, range 20-480 vs. median 68%, range 5-300; P = 0.048), as well as higher magnitude of glucosuria (urine glucose to creatinine ratio, median 0.64, range 0-26 vs. median 0.22, range 0-13; P =  0.023) and frequency of positive glucose dipstick reaction (59% vs. 18%; P =  0.002), than dogs with AKI of other aetiologies. Additional markers of tubular damage considered in this study, including FE of other electrolytes and urinary NGAL, did not differ between groups. In conclusion, when compared to other aetiologies of intrinsic AKI, canine leptospirosis was characterised by increased glucosuria and kaliuresis.

Assessment of neutrophil gelatinase-associated lipocalin as an early biomarker for canine renal ischemia-reperfusion injury

Background

The pathological mechanism of ischemia/reperfusion acute kidney injury (I/R-AKI) differs from other forms of AKI. Neutrophil gelatinase-associated lipocalin (NGAL) is a sensitive biomarker for early diagnosis of AKI, but its utility for diagnosis of canine I/R-AKI remains to be evaluated. The aims of this study were to establish an I/R-AKI model in dogs and to evaluate the diagnostic value of NGAL for canine I/R-AKI.

Methods

We randomly divided 12 beagle dogs into a sham and an I/R group. Artery and vein of the left kidneys of I/R group were cross-clamped for 60 min followed by reperfusion. The kidney samples were analyzed for histopathological lesions. Serum and urinary samples were analyzed for blood urea nitrogen (BUN), serum creatinine (sCr), serum NGAL (sNGAL), urinary creatinine (uCr), and urinary NGAL (uNGAL). Their detection sensitivities and specificities were compared using a receiver operating characteristics (ROC) method. The expression of NGAL in the renal tissues was analyzed by quantitative RT-PCR (qRT-PCR) and immunohistochemical (IHC) analysis.

Results

After I/R, histopathological analysis showed typical AKI lesions in the dog kidneys of the I/R group, but not in the sham group. Compared to that of the sham group, BUN and sCr of the I/R group rose to significant high levels from 24 h after I/R. Both uNGAL and sNGAL rose rapidly from 2 h, reached to the peak levels at 12 h, and then receded to the pre-operation levels by 72 h after I/R. The uNGAL/uCr ratio (uNCR) rose rapidly from 2 h and remained at variably high levels from 6 to 60 h after I/R. The ROC analysis showed that detection sensitivities of uNCR, uNGAL, and sNGAL were significantly (P<0.0001) higher than that of sCr, without significant difference in specificity. The cut-off values of sNGAL, uNGAL and uNCR were 14,642 pg/mL, 6,773 pg/mL, and 6,701 pg/mg, respectively. Both qRT-PCR and IHC analyses confirmed the dynamic expression of NGAL in the dog kidneys with ischemic acute kidney injury (I-AKI).

Conclusions

There is potential for NGAL to be used as a sensitive biomarker for early diagnosis of canine I-AKI.

Urine neutrophil gelatinase-associated lipocalin to diagnose and characterize acute kidney injury in dogs

BACKGROUND

Urine neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker of acute kidney injury (AKI) in dogs.

OBJECTIVES

To evaluate the utility of urinary NGAL for characterizing AKI according to volume responsiveness, presence of inflammation and sepsis, and prognosis.

ANIMALS

Dogs with AKI (n = 76) and healthy controls (n = 10).

METHODS

Prospective study. Clinical and clinicopathologic data including absolute urine NGAL concentration (uNGAL) and NGAL normalized to urine creatinine concentration (uNGALC) were measured upon admission. Dogs were graded according to International Renal Interest Society (IRIS) AKI guidelines and compared based on AKI features: volume-responsive (VR-) AKI vs. intrinsic (I-) AKI based on IRIS criteria; VR-AKI and I-AKI based on urine chemistry; inflammatory versus noninflammatory; septic versus nonseptic; and survivors versus nonsurvivors. Nonparametric statistics were calculated, and significance set at P < .05.

RESULTS

Urinary NGAL was significantly higher in dogs with AKI compared to controls, regardless of AKI grade. Urinary NGAL did not differ between dogs with VR-AKI and I-AKI based on IRIS criteria, whereas higher uNGALC was recorded in dogs with I-AKI based on urine chemistry. Urinary NGAL was significantly higher in dogs with inflammatory AKI, whereas no difference with respect to sepsis or outcome was identified.

CONCLUSIONS AND CLINICAL IMPORTANCE

Urinary NGAL is a sensitive marker for AKI in dogs, but its specificity is affected by systemic inflammation. Increased urinary NGAL in both I-AKI and VR-AKI also suggests the presence of tubular damage in transient AKI. Combining urine chemistry data with IRIS criteria could facilitate AKI characterization in dogs.