Luis Pardo-Marín

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.

Randomized, allopurinol-controlled trial of the effects of dietary nucleotides and active hexose correlated compound in the treatment of canine leishmaniosis

First-line treatment for canine leishmaniosis (CanL) is N-methylglucamine antimoniate (MGA) combined with allopurinol. However, in some dogs allopurinol may induce hyperxanthinuria leading to urolithiasis. Moreover, allopurinol resistance has recently been described in Leishmania infantum isolates from treated dogs with a relapse of the disease. Alternative treatments are thus needed. Since the type of host immune response strongly influences CanL progression and prognosis, dogs could benefit from treatments targeted at modulating such response, such as nucleotides and active hexose correlated compound (AHCC). The aim of this study was to evaluate the effects of an oral combination of nucleotides and AHCC in dogs with clinical leishmaniosis. Sixty-nine dogs with naturally-occurring clinical leishmaniosis were included in this multicenter, open-label, positively-controlled clinical trial and randomized to receive 10mg/kg allopurinol PO BID (allopurinol group) or 17mg/kg AHCC plus 32mg/kg nucleotides PO SID (supplement group) for 180 days. All dogs were also given 50mg/kg MGA SC BID during the first 28 days. At the time points 0, 30, and 180 days of the trial, dogs underwent a clinical examination, and blood, urine, and bone marrow samples were submitted for analytical tests. Final data analyses (allopurinol group: n=29; supplement group: n=24) revealed a significant improvement in both groups in clinical scores and ELISA-determined antibody titers after treatment. However, the supplement group showed a significantly lower clinical score (P=0.005) and significantly higher antibody titers (P=0.032) after 180 days, compared to the allopurinol group. RT-PCR parasite loads were reduced in groups (mean±SD supplement: 0.38±0.56 vs 5.23±18.9; allopurinol: 0.45±1.47 vs 3.09±8.36 parasites/ng of DNA), but there were no significant differences over time or between groups. During the study, 12 dogs in the allopurinol group developed xanthinuria (41%) compared to no dogs (0%) in the supplement group (P=0.000). Both treatments led to significantly increased CD4+/CD8+ ratio, and improvements in protein electrophoretic pattern and acute phase response. In conclusion, 6-month oral treatment with nucleotides and AHCC in addition to MGA showed similar efficacy to the current first-line treatment for CanL, without producing xanthinuria. This combination could be a good alternative to MGA-allopurinol combination treatment for CanL, especially for dogs suffering allopurinol-related adverse events.

Identification of novel biomarkers for treatment monitoring in canine leishmaniosis by high-resolution quantitative proteomic analysis

The objective of this study was to use the Tandem Mass Tag (TMT) isobaric label-based proteomic approach, in order to identify new potential biomarkers for the treatment monitoring of canine leishmaniosis that could not be identified by the use of gel-based techniques. For this purpose serum samples were obtained from 5 clinically diseased dogs before and one month after the treatment of canine leishmaniosis. The non-depleted serum samples were subjected to reduction, alkylation and trypsin digestion, and the resulting peptides were labeled using 6-plex TMT reagents. To obtain information about protein identities and relative quantification, liquid chromatography-MS analysis of multiplexed TMT-labeled peptides was employed. This gel-free, label-based quantitative proteomic approach enabled identification of 117 canine proteins. Among these, 23 showed significant difference (p<0.05) in expression (two downregulated and 21 upregulated ranging from 1.25 to 2.5 fold change). Comparison of gel-free TMT-based quantification and a gel-based approach previously applied to the same samples resulted in the identification of some common markers (Apo-A1, vitamin D binding protein and RBP4). However, 20 additional differentially represented proteins were highlighted by the gel-free approach, 13 of which have not been previously reported in canine leishmaniosis. In conclusion, the TMT-based proteomic approach allowed identification of new serum proteins that significantly change in concentration after canine leishmaniosis treatment. These proteins are involved in various physiopathological processes such as inflammatory, coagulation or defense mechanisms, and could potentially be suitable biomarkers for treatment monitoring of this parasitic disease.

New wide dynamic range assays for quantification of anti-Leishmania IgG2 and IgA antibodies in canine serum

The aims of this study were (1) to develop and validate time resolved-immunofluorometric assays for the detection of anti-Leishmania IgG2 and IgA antibodies in canine serum and (2) to evaluate the ability of these assays to quantify different amounts of anti-Leishmania antibodies in Leishmania-seronegative and seropositive dogs, determined by a commercial ELISA assay, and between different clinical stages according to LeishVet guidelines. The analytical validation showed that the assays had a good precision with intra- and inter-assay coefficients of variation lower than 10%. In addition, the assays allowed the quantification of very low concentration of antibodies as well as demonstrated a high level of accuracy, as determined by linearity under dilution (R2=0.99) and recovery tests (>85%). Moreover, no cross-reactions with Ehrlichia canis, Canine Parvovirus Type 2, Anaplasma phagocytophilum, Babesia canis, Dirofilaria immitis and pyometra were found. The assays were able to detect higher values of anti-Leishmania IgG2 and IgA antibodies in seropositive dogs compared with seronegative dogs (p<0.0001), although an overlap between groups existed in the case of IgA. In addition, significantly higher values for both antibodies were detected in LeishVet groups II (p<0.05) and III (p<0.01) when compared with LeishVet group I. From our study, it could be concluded that the immunofluorometric assays developed would be suitable for determination of anti-Leishmania IgG2 and IgA antibodies in serum samples with an adequate precision, analytical sensitivity and accuracy. In addition, these assays showed a wider difference in the concentration of both IgG2 and IgA antibodies between seronegative and seropositive dogs and between different clinical stages of CanL than a current commercial ELISA kit. Further studies would be recommended to evaluate the diagnostic sensitivity and specificity of these new assays as well as their application in monitoring CanL.

Serum C-reactive protein and ferritin concentrations in dogs undergoing leishmaniosis treatment

Monitoring of selected serum acute phase proteins like C-reactive protein (CRP) and ferritin could be useful for evaluation of the response to treatment in both naturally-occurring and experimentally-induced leishmaniosis. However studies until date have only been focused on dogs with an adequate response to the treatment and there is a lack of knowledge about the possible associations between the CRP and ferritin and the different clinicopathological conditions that can appear after treatment. Thus, the main objective of this retrospective study was to evaluate and compare the serum concentration of CRP and ferritin between three possible situations that dogs which undergo leishmaniosis treatment could have: responsive with total recovery, responsive with only clinical recovery but persistent abnormalities in biochemical analytes, and unresponsive with clinical and biochemical changes. All dogs which totally recovered after treatment showed CRP and ferritin values within reference ranges. Most of dogs classified as having only partial clinical remission had CRP and ferritin within the reference range values despite the presence of other biochemical abnormalities such as hyperglobulinemia, hyperproteinemia, or proteinuria. On the other hand, most of dogs in the unresponsive group had increased CRP and ferritin. Although the study has limitations due to the variability in the protocols and time periods of treatments, it can be concluded that CRP and ferritin concentrations within the reference ranges are usually associated with the absence of clinical signs and adequate response to treatment and increased CRP and/or ferritin values could reflect a lack of appropriate response to treatment.

Serum apolipoprotein-A1 as a possible biomarker for monitoring treatment of canine leishmaniosis

The aims of this study were: the identification of proteins differentially represented in the serum proteome of dogs with leishmaniosis after treatment and the verification of one selected protein as a possible biomarker for treatment monitoring. Serum samples from five dogs with leishmaniosis, before and after treatment were pooled into two groups and analysed using 2-dimensional electrophoresis followed by mass spectrometry analysis (MS). The MS analysis allowed the identification of 8 proteins differently expressed. APO-A1 was selected and an immunoturbidimetric assay was validated for its measurement in dogs. Significantly decreased concentrations of APO-A1 in dogs with leishmaniosis and a significant increase after a good response to the treatment were observed, suggesting that APO-A1 could be a potential biomarker of treatment monitoring with the advantages of an automated measurement.

Evaluation of various biomarkers for kidney monitoring during canine leishmaniosis treatment

BackgroundThe objective of this study was to evaluate and compare the evolution of the profile currently recommended by the International Renal Interest Society (IRIS) (sCr, UPC and sSDMA) with a panel of other different kidney biomarkers during treatment for canine leishmaniosis. This panel included three urinary glomerular biomarkers (uIgG, uCRP and uferritin) and three urinary tubular biomarkers (uGGT, uNAG and uRBP).These biomarkers were measured in two groups of dogs with canine leishmaniosis at IRIS stage I. Group 1: dogs showing proteinuria (UPC > 0.5) before treatment which did not decrease after treatment; Group 2: dogs showing proteinuria before treatment which decreased after treatment.ResultsGroup 1 showed no significant changes in any biomarker after treatment. In group 2, among the biomarkers recommended by the IRIS, only UPC showed a significant decrease after treatment. However all biomarkers of glomerular damage showed a significant decrease after treatment, with uIgG/Cr and uCRP/Cr showing the greater decreases. In addition uRBP/Cr and uNAG/Cr showed significant decreases after treatment.ConclusionsIn dogs with leishmaniosis at IRIS stage I that reduced UPC after treatment, there were no significant changes in serum creatinine and sSDMA. However, all the urine biomarkers evaluated with exception of uGGT showed a significant decrease. These decreases were more evident in those markers related with glomerular function, being uIgG/Cr the biomarker more associated with UPC. Further studies involving a larger number of animals and histological analysis of the kidney would be recommended to confirm these findings and evaluate the routine practical use of these urine biomarkers in canine leishmaniosis.

Changes in serum anti-Leishmania antibody concentrations measured by time-resolved immunofluorometric assays in dogs with leishmaniosis after treatment

The aim of this study was to evaluate the changes in anti-Leishmania IgG2 and IgA antibodies measured by two time-resolved immunofluorometric assays (TR-IFMAs) recently validated and by means of a commercially available ELISA test in dogs with leishmaniosis after treatment. Serum samples from 16 dogs with clinical leishmaniosis were obtained on days 0, 30 and 180 of treatment. In addition, these serological changes were compared with the clinical signs and selected analytes (total proteins, albumin, globulins and urinary protein:creatinine ratio). Concentrations of IgG2 and IgA by TR-IFMA were significantly lower on days 30 (p < 0.05) and 180 of treatment (p < 0.0001) compared to day 0 in dogs that showed a positive response to treatment. Magnitudes of decrease of IgG2 (1.66 and 20.4-fold) and IgA (1.3 and 11.43-fold) concentrations on days 30 and 180 were greater than those of the commercially available ELISA test (1.29 and 2.06-fold), and that of other analytes (total proteins: 1.11 and 1.25-fold; globulins: 1.22 and 1.74-fold; and albumin: 0.93 and 0.8-fold). This study shows that serum IgG2 and IgA anti-Leishmania antibodies measured by TR-IFMAs were useful for treatment monitoring in dogs with leishmaniosis, showing a significant reduction in antibody concentrations earlier than the commercial ELISA assay. Results suggest that the method used for antibody measurements greatly influences the results and, consequently, the usefulness for measuring anti-Leishmania antibodies to monitor the treatment of canine leishmaniosis.

Relationship between serum anti-Leishmania antibody levels and acute phase proteins in dogs with canine leishmaniosis

This study examined the relationship between two serologic assays which quantify anti-Leishmania antibodies (a commercial enzyme-linked immunosorbent assay (ELISA) and a time-resolved immunofluorometric assay (TR-IFMA)) and selected acute phase proteins (APPs) and analytes related to protein concentration. Data were obtained from 205 canine serum samples from different veterinary clinics located in an area in which canine leishmaniosis (CanL) is endemic. The samples were submitted to the Interdisciplinary Laboratory of Clinical Analysis (Interlab-UMU), University of Murcia, Spain, for analysis. The biochemical analytes evaluated were serum ferritin, C-reactive protein (CRP), haptoglobin, paraoxonase-1 (PON-1) and albumin as APPs and total proteins and globulins as indicative analytes of protein concentration. Samples were submitted for the initial diagnosis of CanL, or to monitor the response to treatment in patients with CanL. The evaluation of the biochemical analytes did not show differences between Leishmania-seronegative and Leishmania-seropositive dogs. However, dogs with high antibody titers showed more pronounced clinicopathological abnormalities. Both serological assays had correlations of different significance with the biochemical analytes, showing higher significant correlations with total proteins and globulins than with the rest of the analytes. When the samples submitted for diagnosis and treatment monitoring were analyzed separately, serological assays showed lower correlation in samples for treatment monitoring (r = 0.531, p <  0.0001) than in samples for diagnosis (r = 0.769, p <  0.0001). In addition, higher correlations were found between TR-IFMA and analytes such as serum ferritin and CRP in the treatment monitoring group than with the ELISA. These results may help to clarify the relationship between anti-Leishmania antibody levels and selected biochemical analytes related to inflammation and protein concentration in CanL.

Use of acute phase proteins for the clinical assessment and management of canine leishmaniosis: general recommendations

BackgroundDogs with canine leishmaniosis (CanL) due to Leishmania infantum can show a wide spectrum of clinical and clinicopathological findings at the time of diagnosis. The aim of this paper is to describe the possible application of acute phase proteins (APPs) for the characterization and management of this disease, based on previously published information on the utility of APPs in CanL and the experience of the authors in using APPs as analytes in the profiling of canine diseases.Main bodyDogs diagnosed with L. infantum infection by serology, polymerase chain reaction, cytological or histopathological identification, can be divided into three groups based on their clinical condition at physical examination and their APPs concentrations: Group 1: dogs with no clinical signs on physical examination and APPs in reference range; Group 2: dogs with changes in APPs but no clinical signs on physical examination; Group 3: dogs with clinical signs and changes in APPs. This report describes the main characteristics of each group as well as its association with the clinical classification schemes of CanL.ConclusionAPPs concentration can be a useful clinical tool to characterize and manage CanL.