Kidney Injury Molecule-1 in the detection of early kidney injury in dogs with leptospirosis

Early Detection of Chronic Kidney Disease Using Plasma Neutrophil Gelatinase-Associated Lipocalin and Kidney Injury Molecule-1 in Small-Breed Dogs: A Retrospective Pilot Study

Multiple diagnostic modalities are urgently needed to identify early-stage kidney diseases. Various molecules have been investigated; however, most studies have focused on identifying specific biomarkers in urine. Considering that assessing the symmetrical dimethylarginine (SDMA) plasma concentration is more suitable as an early diagnostic test for chronic kidney disease (CKD) in routine veterinary practice, we aimed to investigate the clinical usefulness of plasma neutrophil gelatinase-associated lipocalin (pNGAL) and plasma kidney injury molecule-1 (pKIM-1) concentrations for CKD detection in small-breed dogs. Through a retrospective analysis, we found that numerous clinicopathological data showed a log-normal distribution, even when they satisfied normality tests. Moreover, the log-transformed pNGAL and pKIM-1 concentrations successfully identified CKD International Renal Interest Society (IRIS) stages 1-4 and the risk group with underlying CKD risk factors. Correlation analysis and group comparison of other factors confirmed the possibility of using these two biomarkers for detecting the CKD risk group and IRIS stage 1. Receiver operating characteristic curve analysis revealed that the diagnostic accuracy for discriminating the risk group was superior in the order of pKIM-1, pNGAL, SDMA, and serum creatinine levels. In conclusion, these results suggest that pKIM-1 and pNGAL are possible early or quantifiable markers of insignificant CKD or can be at least used as an adjunct with traditional indicators.

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.

Determination of the reference interval for urine kidney injury molecule-1 in 50 healthy cats

OBJECTIVES

The aim of the present study was to establish a reference interval (RI) for urine kidney injury molecule-1 (KIM-1) in healthy cats.

METHODS

History, physical examination, blood pressure, and feline immunodeficiency virus and feline leukemia virus serology status were determined. A complete blood cell count, serum biochemical profile, urinalysis and kidney ultrasound were performed, and N-terminal pro-brain natriuretic peptide, total thyroxine (TT4) and urine KIM-1 were measured. An RI was calculated and the effect of age, sex, body condition score (BCS), blood pressure, symmetric dimethylarginine (SDMA), serum creatinine concentration (SCr), phosphorus, TT4, urine specific gravity (USG) and mid-sagittal kidney length on urine KIM-1 was evaluated using a general linear model.

RESULTS

Of 69 recruited cats, 50 met the inclusion criteria. There were 35 male cats and 15 female cats, with a median age of 4.3 years (range 1.0-12.3), median weight of 5.11 kg (range 2.52-8.45) and median BCS of 6/9 (range 3-8). The median serum concentrations were SDMA 11.0 µg/dl (range 2-14), SCr 88.5 µmol/l (range 47-136), phosphorus 1.41 mmol/l (range 0.8-2.2) and TT4 32.0 nmol/l (range 17-51). Median USG was 1.057 (range 1.035-1.076), mid-sagittal left kidney length was 3.50 cm (range 2.94-4.45) and mid-sagittal right kidney length was 3.70 cm (range 3.06-4.55). The derived RI for urine KIM-1 was 0.02-0.68. USG was a significant (P <0.001) predictor of urine KIM-1. Individually, age, sex, blood pressure, BCS, SDMA, SCr, phosphorus, TT4 and mid-sagittal kidney length were not significant predictors of urine KIM-1. In a multivariate model, if combined with USG, SDMA concentration was predictive (P = 0.030) of urine KIM-1.

CONCLUSIONS AND RELEVANCE

Urine concentration was significantly correlated with urine KIM-1, which will be an important consideration when interpreting findings in cats with potential kidney injury.

Kidney Injury Biomarkers in Leptospirosis

Leptospirosis is a zoonotic infection with a global distribution, though it has a greater impact on marginalized rural agricultural and urban communities in developing countries. Kidney injury, which can lead to severe and lethal infections, is the most frequent complication associated with leptospirosis. Novel biomarkers are being studied as tools for assessing kidney injury in different pathological processes to improve early detection. This review aimed to gather information on the use of novel kidney biomarkers for human leptospirosis. A search of the literature was carried out in September 2021 using the parameters "((kidney) OR (renal) OR (chronic kidney disease) OR (acute kidney injury)) AND ((biomarker) OR (marker)) AND ((Leptospira) OR (leptospirosis))". The review identified 11 original studies that evaluated the performance of 15 kidney biomarkers related to leptospirosis. Assessment of the evidence for biomarker utility was limited because of the small number of studies and sample sizes. Although some biomarkers were associated with kidney disease, no specific biomarker appeared to be ready for clinical practice, and more research in this field is necessary.

Short-term intra-individual variation of urinary biomarkers in dogs with stable chronic kidney disease

BACKGROUND

Active-ongoing kidney damage is present in animals with stable chronic kidney disease (CKD), as reflected by biomarkers in urine. Interpretation of serial messurements of biomarkers requires knowledge of its intra-individual variation.

AIMS

To evaluate the short-term intra-individual variation of urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 (uNGAL, uKIM-1, respectively) in dogs with stable CKD, and to determine whether normalization to urinary creatinine (uCr) decreases variation.

ANIMALS

Twenty-five dogs with naturally-occurring stable CKD.

METHODS

Prospective, observational study. Dogs were diagnosed with CKD based on the International Renal Interest Society guidelines. Dogs were included only if the variation in serum creatinine concentration was <25% on at least 2 measurements during the 3 months preceding inclusion, and only if serum creatinine variation was <20% during the 14-day study period. Urine samples were collected on days 0, 4, 10 and 14. uNGAL and uKIM-1 were measured using ELISA.

RESULTS

The median coefficients of variation (CV) of uNGAL and uNGAL/uCr were 42% (range, 7%-127%), and 44% (range, 8%-100%), respectively, and the CV 90th percentiles were 97% and 83%, respectively. The median CV of uKIM-1 and uKIM-1/uCr were 29% (range, 16%-91%), and 23% (range, 6%-76%), respectively, and the CV 90th percentiles were 56% and 52%, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Changes of >100% and >60% for uNGAL and uKIM-1, respectively, in serial measurements are higher than the normal expected variation and therefore might indicate need for further investigation for underlying causes of kidney damage.