Urinary chemical fingerprint left behind by repeated NSAID administration: Discovery of putative biomarkers using artificial intelligence.

Prediction and early detection of kidney damage induced by nonsteroidal anti-inflammatories (NSAIDs) would provide the best chances of maximizing the anti-inflammatory effects while minimizing the risk of kidney damage. Unfortunately, biomarkers for detecting NSAID-induced kidney damage in cats remain to be discovered. To identify potential urinary biomarkers for monitoring NSAID-based treatments, we applied an untargeted metabolomics approach to urine collected from cats treated repeatedly with meloxicam or saline for up to 17 days. Applying multivariate analysis, this study identified a panel of seven metabolites that discriminate meloxicam treated from saline treated cats. Combining artificial intelligence machine learning algorithms and an independent testing urinary metabolome data set from cats with meloxicam-induced kidney damage, a panel of metabolites was identified and validated. The panel of metabolites including tryptophan, tyrosine, taurine, threonic acid, pseudouridine, xylitol and lyxitol, successfully distinguish meloxicam-treated and saline-treated cats with up to 75-100% sensitivity and specificity. This panel of urinary metabolites may prove a useful and non-invasive diagnostic tool for monitoring potential NSAID induced kidney injury in feline patients and may act as the framework for identifying urine biomarkers of NSAID induced injury in other species.

[Transaldolase deficiency - clinical outcome, pathogenesis, diagnostic process].

Transaldolase deficiency is a rare inborn autosomal recessive error of the pentose phosphate pathway that, to date, has been diagnosed in 33 patients, including 4 from Poland. The aim of this manuscript was to present the clinical presentation, pathogenesis and diagnostic process of transaldolase deficiency. The authors also present a diagnostic algorithm of transaldolase deficiency.

Prospective evaluation of a combination of fungal biomarkers for the diagnosis of invasive fungal disease in high-risk haematology patients.

We prospectively evaluated a combination of fungal biomarkers in adult haematology patients with focus on their clinical utility at different time points during the course of infection. In total, 135 patients were monitored once to twice weekly for serum (1-3)-ß-d-glucan (BG), galactomannan (GM), bis-methyl-gliotoxin and urinary d-arabinitol/l-arabinitol ratio. In all, 13 cases with proven or probable invasive fungal disease (IFD) were identified. The sensitivity of BG and GM at the time of diagnosis (TOD) was low, but within 2 weeks from the TOD the sensitivity of BG was 92%. BG >800 pg/mL was highly specific for IFD. At a pre-test probability of 12%, both BG and GM had negative predictive values (NPV) >0.9 but low positive predictive values (PPV). In a subgroup analysis of patients with clinically suspected IFD (pre-test probability of 35%), the NPV was lower, but the PPV for BG was 0.86 at cut-off 160 pg/mL. Among IFD patients, 91% had patterns of consecutively positive and increasing BG levels. Bis-methyl-gliotoxin was undetectable in 15 patients with proven, probable and possible IA. To conclude, BG was the superior fungal marker for IFD diagnosis. Quantification above the limit of detection and graphical evaluation of the pattern of dynamics are warranted in the interpretation of BG results.

Early diagnosis of fungal infections using piezomicrogravimetric and electric chemosensors based on polymers molecularly imprinted with d-arabitol.

An elevated concentration of d-arabitol in urine, especially compared to that of l-arabitol or creatinine, is indicative of a fungal infection. For that purpose, we devised, fabricated, and tested chemical sensors determining d-arabitol. These chemosensors comprised the quartz crystal resonator (QCR) or extended-gate field-effect transistor (EG-FET) transducers integrated with molecularly imprinted polymer (MIP) film recognition units. To this end, we successfully applied a covalent approach to molecular imprinting, which involved formation of weak reversible covalent bonds between vicinal hydroxyl groups of arabitol and boronic acid substituents of the bithiophene functional monomer used. The MIP films were synthesized and simultaneously deposited on gold electrodes of quartz crystal resonators (Au-QCRs) or Au-glass slides by oxidative potentiodynamic electropolymerization. With the QCR and EG-FET chemosensors, the d-arabitol concentration was determined under flow-injection analysis and stagnant-solution binding conditions, respectively. Selectivity with respect to common interferences, and l-arabitol in particular, of the devised chemosensors was superior. Limits of detection and linear dynamic concentration ranges of the QCR and EG-FET chemosensors were 0.15 mM and 0.15 to 1.25 mM as well as 0.12 mM and 0.12 to 1.00 mM, respectively, being lower than the d-arabitol concentrations in urine of patients with invasive candidiasis (>220 µM). Therefore, the devised chemosensors are suitable for early diagnosis of fungal infections caused by Candida sp. yeasts.

Identification of organic acids as potential biomarkers in the urine of autistic children using gas chromatography/mass spectrometry.

There is a need to identify metabolic phenotypes in autism as they might each require unique approaches to prevention. Biological markers can help define autism subtypes and reveal potential therapeutic targets. The aim of the study was to identify alterations of small molecular weight compounds and to find potential biomarkers. Gas chromatography/mass spectrometry was employed to evaluate major metabolic changes in low molecular weight urine metabolites of 14 children with autism spectrum disorders vs. 10 non-autistic subjects. The results prove the usefulness of an identified set of 21 endogenous compounds (including 14 organic acids), whose levels are changed in diseased children. Gas chromatography/mass spectrometry method combined with multivariate statistical analysis techniques provide an efficient way of depicting metabolic perturbations of diseases, and may potentially be applicable as a novel strategy for the noninvasive diagnosis and treatment of autism.

Sensitive measurement of polyols in urine by capillary zone electrophoresis coupled with amperometric detection using on-column complexation with borate.

Little is known about human polyol metabolism, but recent studies indicate that abnormal polyol concentrations in body fluids are related to several diseases. In this study, a rapid and sensitive method for the determination of seven major polyols in urine including two groups of polyol isomers, C5-polyols (Rib+Arb+Xyl) and C6-polyols (Sor+Gal+Man), was developed using capillary zone electrophoresis coupled with amperometric detection (CZE-AD). The effects of the working electrode potential, pH, running buffer components and concentrations, separation voltage and injection times were investigated. Under the optimised conditions, seven types of polyols could be perfectly separated via the formation of anionic polyol-borate complexes in a borate buffer solution. Highly linear current responses to the polyol concentrations were obtained with good correlation (0.9984

The level of arabinitol in autistic children after probiotic therapy.

OBJECTIVE: The level of D-arabinitol (DA) and the ratio of D-/L-arabinitol (DA/LA) in the urine of children with autism were investigated. The changes in DA/LA after probiotic treatment in urine samples of children with autism were studied. METHODS: DA and LA and the DA/LA ratio were identified by capillary gas chromatography/mass spectrometry in urine before and after the probiotic therapy. RESULTS: The level of DA is significantly higher (P < 0.05) in the urine of autistic children before (A) and after probiotic supplementation (A1) (160.04 ± 22.88 µmol/mmol creatinine and 89.53 ± 37.41 µmol/mmol creatinine, respectively). Nonetheless, the probiotic supplementation let to a significant decrease in DA and DA/LA and to a significant improvement in ability of concentration and carrying out orders. CONCLUSION: The use of probiotics seems to be helpful in reducing the level of DA and the ratio of DA/LA in the urine of children with autism.

Determination of urinary D-/L-arabinitol ratios as a biomarker for invasive candidiasis in children with cardiac diseases.

A non-invasive, non-culture-based method of determining urinary D-/L-arabinitol (D-/L-ARA) ratios was investigated as a tool for the diagnosis of invasive candidiasis in nosocomial paediatric infection cases. The study encompassed 138 children aged 4 days to 16 years (mean ± SD=1.6 ± 4.2 years) with congenital heart defects (91.4%) or with rhythm disorders or circulatory failure (8.6%). ARA enantiomers were detected by GC using an electron capture detector. Positive D-/L-ARA ratios were found for 11/11 patients with proven candidiasis and 17/19 patients with clinically suspected invasive candidiasis. Thirty children were undergoing antifungal chemotherapy. D-/L-ARA ratios (mean ± SD) were 2.601 ± 0.544 in hospitalized cardiac patients without fungal infection and 5.120 ± 1.253 in those receiving antifungal therapy (P<0.001). The sensitivity of the method was 100%, the specificity 97.2%, the positive predictive value was 78.6% and the negative predictive value was 100%.

Mitochondrial involvement and erythronic acid as a novel biomarker in transaldolase deficiency.

BACKGROUND: Sedoheptulose, arabitol, ribitol, and erythritol have been identified as key diagnostic metabolites in TALDO deficiency. METHOD: Urine from 6 TALDO-deficient patients and TALDO-deficient knock-out mice were analyzed using ¹H-NMR spectroscopy and GC-mass spectrometry. RESULTS: Our data confirm the known metabolic characteristics in TALDO-deficient patients. The ß-furanose form was the major sedoheptulose anomer in TALDO-deficient patients. Erythronic acid was identified as a major abnormal metabolite in all patients and in knock-out TALDO mice implicating an as yet unknown biochemical pathway in this disease. A putative sequence of enzymatic reactions leading to the formation of erythronic acid is presented. The urinary concentration of the citric acid cycle intermediates 2-oxoglutaric acid and fumaric acid was increased in the majority of TALDO-deficient patients but not in the knock-out mice. CONCLUSION: Erythronic acid is a novel and major hallmark in TALDO deficiency. The pathway leading to its production may play a role in healthy humans as well. In TALDO-deficient patients, there is an increased flux through this pathway. The finding of increased citric acid cycle intermediates hints toward a disturbed mitochondrial metabolism in TALDO deficiency.

Urinary excretion of pentose phosphate pathway-associated polyols in early postnatal life.

BACKGROUND: Two new inborn errors in the pentose phosphate pathway have been described: ribose-5-isomerase deficiency and transaldolase deficiency. These defects are characterized by accumulation of specific polyols in body fluids. Little is known about human polyol metabolism, but there are indications for a physiological role primarily during early development. OBJECTIVES: The objective of this study was to evaluate the urinary excretion of polyols in neonates with special interest on a possible impact of the grade of maturity. For comparison, urinary polyol excretion in older children was also studied. METHODS: Urine samples of 40 neonates born between gestational week 25 and 41 were analyzed for the excretion of pentose phosphate pathway-associated polyols (erythritol, D-arabitol, ribitol, xylitol). These metabolites were also quantified in urine obtained from 77 children aged 4 weeks to 10 years. RESULTS: The results show high urinary polyol excretions after birth independent of the week of gestation. During the first months of life, the concentrations decreased exponentially and reached a fairly stable steady state thereafter. CONCLUSIONS: Urinary excretion of polyols shows an age dependency with highest concentrations postnatally independent of the grade of maturity. These findings suggest a possible connection between the formation of pentose phosphate pathway-associated polyols and fetal development.

Electrokinetic probes for single-step screening of polyol stereoisomers: the virtues of ternary boronate ester complex formation.

Electrokinetic probes based on the differential migration of ternary boronate ester complexes permit the selective analysis of micromolar levels of UV-transparent polyol stereoisomers in urine samples via dynamic complexation-capillary electrophoresis that is applicable to single-step screening of in-born errors of sugar metabolism, such as galactosemia.

Clinical experience of urine D-arabinitol/L-arabinitol ratio in the early diagnosis of invasive candidiasis in paediatric high risk populations.

In 2 prospective studies, we previously reported on the early and accurate diagnosis of invasive candidiasis by determining the D-arabinitol/L-arabinitol (DA/LA) ratio in urine in neutropenic children with cancer at the paediatric oncology unit (POU) and in premature infants at the neonatal intensive care unit (NICU) at our hospital. In this retrospective study at the same units, we report how the DA/LA assay was implemented in clinical practice immediately after the prospective study periods. We found that, in the POU, the recommendation of regularly monitoring urine DA/LA ratios in patients at risk and considering antifungal therapy in the case of elevated ratios had been followed. A significant decrease in the incidence of culture positive invasive candidiasis may have been attributed to the introduction of the DA/LA assay. At the NICU, where the DA/LA assay was recommended only as an adjunct to other diagnostic tools, morbidity in invasive candidiasis remained unchanged. While regular monitoring of the urine DA/LA ratio probably facilitates the early detection of invasive candidiasis in paediatric oncology, it remains to be determined if the test can be used in a similar way in neonatal intensive care.

Anemia impairs small intestinal absorption measured by intestinal permeability in children.

OBJECTIVE: To determine the effect of anemia and iron status on intestinal permeability in children. DESIGN: A routine prospective study was performed in 64 children with symptoms suggesting cow's milk allergy (CMA) (11.8 +/- 16 mo, 2-94 mo). They exhibited a negative cow's milk challenge upon the ESPGHAN criteria. Hemoglobin (Hb), mean corpuscular volume (MCV), blood iron (Fe) and ferritin (Fer) concentrations were studied in all. Permeability was measured as percent of urinary excretion of lactitol (L,%) and mannitol (M,%) (oral absorption, 0.1 g/Kg for each sugar) and determination of the L/M ratio (L/M,%). RESULTS: L/M was significantly higher in anemic children than in non-anemic ones, 2.45, (median), 1.92-3.43 (extremes), n = 29, vs. 1.72, 1.56-2.18, n = 35, p = 0.03. Hb correlated negatively with L/M (p = 0.0001) and L (p = 0.05) and positively with M (p = 0.03). Also, L/M correlated negatively with MCV (p = 0.001) and Fe (p = 0.04). CONCLUSION: IP depends on anemia and iron status. The interpretation of IP should be taken cautiously into account in the diagnosis of CMA in case of anemia or iron deficiency.

Transaldolase deficiency: a new cause of hydrops fetalis and neonatal multi-organ disease.

Transaldolase (TALDO) deficiency is a newly recognized metabolic disease, which has been reported so far in 2 patients presenting with liver failure and cirrhosis. We report a new sibship of 4 infants born to the same consanguineous parents; all presented at birth or in the antenatal period with dysmorphic features, cutis laxa and hypertrichosis, hepatomegaly, splenomegaly, liver failure, hemolytic anemia, thrombocytopenia, and genitourinary malformations. The clinical courses were variable: the first child died of liver failure at 4 months of age; the second pregnancy was medically terminated at 28 weeks gestation because of hydrops fetalis with oligohydramnios. The third child is doing well at age 7 with liver fibrosis and mild kidney failure. The fourth child is now 21 months old and has hepatosplenomegaly, mild anemia, and thrombocytopenia. Urine assessment of polyols showed elevations of erythritol, arabitol, and ribitol consistent with TALDO deficiency. TALDO activity was undetectable in the patients' tissues, and mutation in the TALDO1 gene was found in the 4 patients.

Simultaneous measurement of urinary polyols using gas chromatography/mass spectrometry.

In the present study, we simultaneously measured several polyols, such as adonitol, arabitol, dulcitol, glucose, myo-inositol, mannitol, sorbitol, and xylitol, in urine by gas chromatography/mass spectrometry-positive chemical ionization. We also examined possible relationship between the levels of these metabolites and age in normal individuals. In order to proceed to its quantification by GC/MS, 200 microL of a urine sample were diluted with 3 ml of distilled water, lyophilized, acetylated, and then analyzed them. Using this method, we were able to quantify as little as 0.5-1.0 ng/microL, and we made the calibration curves to be linear from 0.25 to 250 ng/microL (r(2)>0.991). Analytical recoveries were over 89.4%, and the inter-day and intra-day variability for accuracy and reproducibility was less than 20%. In the normal urine sample, the levels of polyols were gender-differentiated and age-related. This simple GC/MS method is sensitive and allows the measurement of wide ranges of polyols using small amounts of urine. We conclude that the quantitation of urinary polyols using GC/MS appears to be a clinically useful method for assessing polyol-pathway activity.

Urinary D-arabinitol/L-arabinitol levels in infants undergoing long-term antibiotic therapy.

Long-term antibiotic therapy is one of the main risk factors for mycosis. The urinary D-arabinitol/L-arabinitol (D-/L-ARA) ratio (a biomarker of several Candida species) was determined by gas chromatography with an electron capture detector in samples from 51 infants undergoing long-term antibiotic therapy. Although 47 of these children had higher D-/L-ARA ratios than healthy controls (P<0.0003), their values nonetheless remained within upper-normal limits (D-/L-ARA ratio of <3.6). Four children with suspected invasive candidiasis had above-normal ratios that normalized with fluconazole treatment.

Analysis of polyols in urine by liquid chromatography-tandem mass spectrometry: a useful tool for recognition of inborn errors affecting polyol metabolism.

Several inborn errors of metabolism with abnormal polyol concentrations in body fluids are known to date. Most of these defects can be diagnosed by the assessment of urinary concentrations of polyols. We present two methods using tandem mass spectrometry for screening for inborn errors affecting polyol metabolism. Urine samples supplemented with internal standards ([13C4]erythritol, [13C2]arabitol and [2H3]sorbitol) were desalted by a mixed-bed ion-exchange resin. Separation was achieved by two different columns. Sugar isomers could not be separated using a Prevail Carbohydrate ES 54 column (method 1), whereas with the other column (Aminex HPX-87C) separation of the isomers was achieved (method 2). Multiple reaction monitoring polyol detection was achieved by tandem mass spectrometry with an electron ion-spray source operating in the negative mode. Age-related reference ranges of polyols (erythritol, treitol, arabitol, ribitol, xylitol, galactitol, mannitol, sorbitol, sedoheptitol and perseitol) in urine were established. The applicability of the method was demonstrated by the abnormal polyol concentrations observed in patients with transaldolase deficiency, ribose-5-phosphate isomerase deficiency and classical galactosaemia. This paper describes two methods for the analysis of urinary polyols by liquid chromatography-tandem mass spectrometry. Method 1 is a fast screening method with the quantification of total isomers and method 2 is a more selective method with the separate quantification of the polyols. Both methods can be used for diagnosing inborn errors of metabolism affecting polyol metabolism.

Development and application of a rapid diagnostic method for invasive Candidiasis by the detection of D-/L-arabinitol using gas chromatography/mass spectrometry.

A rapid non-culture-based diagnostic method utilizing d-/l-arabinitol (DA/LA) ratios as a chemical marker of invasive candidiasis was developed and explored. The enantiomers-ratios detection was made possible by the use of gas chromatography coupled with mass spectrometry (GC/MS). The mean DA/LA ratios +/- standard deviation (range) in urine (n = 40) and serum (n = 20) were 2.08 +/- 0.78 (0.57 to 3.55) and 1.79 +/- 0.75 (0.74 to 3.54), respectively, from patients without evidence of fungal infection or colonization; in patients (n = 7) with culture-proven invasive candida infections, the figures were 9.91 +/- 3.04 (7.24 to 16.27) and 13.58 +/- 7.31 (5.57 to 25.88) in urine and serum, respectively. The differences in DA/LA ratios between the candidemic patients and the non-candidemic patients were statistically significant (p < 0.01) in both serum and urine samples. The DA/LA ratios were not significantly affected in patients with oral or vaginal candidiasis and candiduria.

Ribose-5-phosphate isomerase deficiency: new inborn error in the pentose phosphate pathway associated with a slowly progressive leukoencephalopathy.

The present article describes the first patient with a deficiency of ribose-5-phosphate isomerase (RPI) (Enzyme Commission number 5.3.1.6) who presented with leukoencephalopathy and peripheral neuropathy. Proton magnetic resonance spectroscopy of the brain revealed highly elevated levels of the polyols ribitol and D-arabitol, which were subsequently also found in high concentrations in body fluids. Deficient activity of RPI, one of the pentose-phosphate-pathway (PPP) enzymes, was demonstrated in fibroblasts. RPI gene-sequence analysis revealed a frameshift and a missense mutation. Recently, we described a patient with liver cirrhosis and abnormal polyol levels in body fluids, related to a deficiency of transaldolase, another enzyme in the PPP. RPI is the second known inborn error in the reversible phase of the PPP, confirming that defects in pentose and polyol metabolism constitute a new area of inborn metabolic disorders.