Biomarkers and renal arterial resistive index in dogs naturally infected with Leishmania infantum

Urinary Tamm-Horsfall protein excretion is a potential early biomarker of renal distal tubular damage in canine leishmaniosis

This study evaluates distal tubular damage in early stages of renal disease in dogs with naturally acquired leishmaniosis. Pherograms of urinary proteins separated in vertical electrophoresis system (SDS-PAGE) were evaluated. Peptide fingerprint and fragmentation (MALDI-TOF TOF) identified bands located at 100 and 60 kDa as Tamm-Horsfall protein (THP) and albumin, respectively. The variables examined were: urine protein to creatinine ratio (UPC), total number of bands, quantification of THP urinary excretion through the optical density (OD %) of bands located at 100 kDa, blood creatinine, and urine specific gravity (USG). Positive correlation was found between UPC and the number of bands (ρ = 0.75849, P = <0.0001). Negative correlation was identified between UPC and OD % of 100 kDa bands (ρ = -0.85332, P = <0.0001), and the number of bands and OD % of 100 kDa bands (ρ = -0.74479, P = <0.0001). The area under the ROC curve was 0.991 (95 % CI, 0.976-1). The optimal cut-off UPC that better discriminated between urines with high or low OD% of THP was 0.46 with 92.6 % sensitivity and 96.2 % specificity. Our findings indicate that non azotemic dogs with borderline proteinuria might excrete low amount of THP, which could suggest tubular damage in early stages of chronic kidney disease.

A link between circulating immune complexes and acute kidney injury in human visceral leishmaniasis

Visceral leishmaniasis (VL) is an infectious disease caused by Leishmania infantum. Clinically, VL evolves with systemic impairment, immunosuppression and hyperactivation with hypergammaglobulinemia. Although renal involvement has been recognized, a dearth of understanding about the underlying mechanisms driving acute kidney injury (AKI) in VL remains. We aimed to evaluate the involvement of immunoglobulins (Igs) and immune complexes (CIC) in the occurrence of AKI in VL patients. Fourteen VL patients were evaluated between early treatment and 12 months post-treatment (mpt). Anti-Leishmania Igs, CIC, cystatin C, C3a and C5a were assessed and correlated with AKI markers. Interestingly, high levels of CIC were observed in VL patients up to 6 mpt. Concomitantly, twelve patients met the criteria for AKI, while high levels of cystatin C were observed up to 6 mpt. Plasmatic cystatin C was positively correlated with CIC and Igs. Moreover, C5a was correlated with cystatin C, CIC and Igs. We did not identify any correlation between amphotericin B use and kidney function markers in VL patients, although this association needs to be further explored in subsequent studies. Our data reinforce the presence of an important renal function impairment during VL, suggesting the involvement of Igs, CIC, and C5a in this clinical condition.

The association between rLiHyp1 protein plus adjuvant and amphotericin B is an effective immunotherapy against visceral leishmaniasis in mice

Treatment of visceral leishmaniasis (VL) is compromised by drug toxicity, high cost and/or the emergence of resistant strains. Though canine vaccines are available, there are no licensed prophylactic human vaccines. One strategy to improve clinical outcome for infected patients is immunotherapy, which associates a chemotherapy that acts directly to reduce parasitism and the administration of an immunogen-adjuvant that activates the host protective Th1-type immune response. In this study, we evaluated an immunotherapy protocol in a murine model by combining recombinant (r)LiHyp1 (a hypothetical amastigote-specific Leishmania protein protective against Leishmania infantum infection), with monophosphoryl-lipid A (MPLA) as adjuvant and amphotericin B (AmpB) as reference antileishmanial drug. We used this protocol to treat L. infantum infected-BALB/c mice, and parasitological, immunological and toxicological evaluations were performed at 1 and 30 days after treatment. Results showed that mice treated with rLiHyp1/MPLA/AmpB presented the lowest parasite burden in all organs evaluated, when both a limiting dilution technique and qPCR were used. In addition, these animals produced higher levels of IFN-γ and IL-12 cytokines and IgG2a isotype antibody, which were associated with lower production of IL-4 and IL-10 and IgG1 isotype. Furthermore, low levels of renal and hepatic damage markers were found in animals treated with rLiHyp1/MPLA/AmpB possibly reflecting the lower parasite load, as compared to the other groups. We conclude that the rLiHyp1/MPLA/AmpB combination could be considered in future studies as an immunotherapy protocol to treat against VL.

Urinary cystatin C and N-acetyl-beta-D-glucosaminidase (NAG) as early biomarkers for renal disease in dogs with leishmaniosis

Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum that can vary from a subclinical infection to a severe disease. Dogs affected with CanL present varying degrees of renal dysfunction. Unfortunately, traditional biomarkers such as urea and creatinine detect renal damage in advanced stages of the disease, so more accurate biomarkers are needed. Hence, we aimed to study how urinary cystatin C (CysC) and N-acetyl-beta-D-glucosaminidase (NAG), behave in dogs with CanL at different stages of the disease. Eighty-six CanL infected dogs were classified according to LeishVet stages: LI (16 dogs), LIIa (12 dogs), LIIb (12 dogs), LIII (16 dogs) and LIV (30 dogs); as a control, 17 healthy dogs were studied. Blood samples were collected for complete haematological and biochemistry analysis including plasma cystatin C. Urine analysis included urine specific gravity (USG), urine protein to creatinine ratio (UPC), CysC and NAG expressed as a ratio with creatinine uCysCc (μg/g) and uNAGc (IU/g). The haematological, biochemical and urinary analysis coincided with the LeishVet guidelines. The statistical study of the uCysCc ratio and the uNAGc, showed significant increase when compared against control starting from group LI (p < 0.05). Interestingly, when the cut-off values were calculated using the ROC curve, uCysCc (258.85 µg/g) and uNAGc (2.25 IU/g) 75 % of the dogs included in LI groups surpassed the threshold. Hence our study indicates that uCysCc and uNAGc, could help to detect early renal damage in CanL affected dogs.

Prospective evaluation of 5 urinary biomarkers as predictors of acute kidney injury in nonazotemic, hospitalized dogs

BACKGROUND

Early recognition of acute kidney injury (AKI) is hindered by current definitions and use of traditional, insensitive markers.

HYPOTHESIS/OBJECTIVES

Urinary (u) activity of γ-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP), and concentrations of heat-shock protein 70 (HSP70) and interleukins (ILs) -6 and -18, are predictive biomarkers for AKI and survival.

ANIMALS

Nonazotemic, hospitalized dogs (n = 118) and healthy controls (n = 20).

METHODS

A prospective observational study. Nonazotemic dogs at risk of AKI were recruited and their urinary biomarker concentrations were measured at presentation. Serum creatinine (sCr) and symmetric dimethylarginine (sSDMA) were measured daily until discharge/death.

RESULTS

The overall case fatality rate was 18.6%. Fifteen dogs (12.7%) developed AKI, which was associated with death (relative risk, 3.2; 95% confidence interval [CI], 1.57-6.55). All 5 urinary biomarkers were significantly higher in hospitalized dogs compared to controls, with minimal overlap. uHSP70/uCr, uGGT/uCr, and uIL-6/uCr at presentation were higher in dogs which later developed AKI. Areas under the receiver operator characteristic curve (AUROC) (95% CI) for the 3 biomarkers as predictors of AKI were 0.67 (0.51-0.83), 0.68 (0.55-0.81), and 0.78 (0.65-0.91), respectively. When they were categorically classified as elevated/normal, each additional elevated biomarker increased the odds for AKI (OR, 2.83; 95% CI, 1.23-6.52, P = .01). Agreement between sCr and sSDMA was poor (Cohen's kappa = .071). The AUROC of SDMA at presentation for AKI prediction was 0.73 (0.51-0.95).

CONCLUSIONS AND CLINICAL IMPORTANCE

Kidney injury was common, irrespective of subsequent worsening of azotemia or death. The predictive value of individual urinary biomarkers was reduced by moderate sensitivities and specificities. SDMA showed moderate discriminatory utility for AKI prediction, and often displayed discordant results with sCr.

Short term impacts of meglumine antimoniate treatment on kidney function in dogs with clinical leishmaniosis

This study examines correlations among serum proteins, clinical score, body weight and kidney function biomarkers after a standard treatment course (meglumine antimoniate plus allopurinol) in twelve Canine leishmaniosis (CanL) patients at the three times points pre treatment, after treatment and after the end of treatment. The laboratory variables measured were those used for the follow-up of sick dogs along with biomarkers of kidney function: glomerular filtration rate (GFR), creatinine (Cr), urea, calcium, inorganic phosphorus, urine specific gravity (USG) and urine protein to creatinine ratio (UPC). Arterial blood pressure (systolic blood pressure, SBP), clinical score (CS) and weight were also monitored over the study period. At Tp0, GFR was within the normal range in most dogs. Hyperfiltration was detected in three patients and hypofiltration in one. In dogs showing hyperfiltration, this factor remained in the non-azotemic range over the whole study period. After treatment normal filtration values were recovered. Meglumine antimoniate did not modify GFR or USG. A significant reduction in UPC was recorded. In all dogs, clinical scores improved. Negative correlation was found between GFR and Cr, UPC and albumin (Alb) and CS and Alb, while positive correlation was detected between UPC and total globulins (GlobT), CS and GlobT, UPC and total solids (TS), SBP and CS and SBP and UPC. Our findings indicate no impacts on kidney function of the treatment of CanL with meglumine antimoniate, as no effects were produced on GFR or USG. Treatment was effective and found to reduce UPC which could suggest improved glomerular injury.