Avoiding falsely low creatinine concentrations measured in patients treated with N-acetylcysteine for acetaminophen intoxication using enzymo-amperometric method - An in vitro and in vivo study.

BACKGROUND: Circulating creatinine is a biomarker of paramount importance in clinical practice. In cases of acetaminophen (APAP) intoxication, the antidote, N-acetylcysteine (NAC), interferes with commonly used creatininase-peroxidase methods. This study aimed to assess whether creatininase-amperometric methods were affected in this context. METHODS: This study includes in vitro interference tests, involving four creatinine assays using NAC-spiked plasma pools and an in vivo retrospective study comparing creatininase-peroxidase and creatininase-amperometric measurements in patients presenting with NAC-treated APAP poisoning. RESULTS: Creatininase-peroxidase method was impacted by NAC interference in a clinically-significant manner at therapeutic NAC levels (basal value recovery of 80 % and 70 % for 500 and 1000 mg.L-1 of NAC, respectively), surpassing the desirable Reference Change Value (RCV%). Enzymo-amperometric methods were not impacted. Among patients, a mean bias of -45.2 ± 28.0 % was observed for the peroxidase detection method compared to the amperometric in those who received NAC prior plasma sampling and -2.7 ± 5.4 % in those who did not. CONCLUSIONS: Our findings indicate that enzymo-amperometric creatinine assays remain unaffected by NAC interference due to the absence of the peroxidase step in the analytical process. Therefore, these methods are suitable to prevent spurious hypocreatininemia in APAP intoxicated patients undergoing NAC therapy.

Early detection of plasma d-lactate: Toward a new highly-specific biomarker of bacteraemia?

Background: Bloodstream infections are a leading cause of mortality. Their detection relies on blood cultures (BCs) but time to positivity is often between tens of hours and days. d-lactate is a metabolite widely produced by bacteria but very few in human. We aimed to evaluate d-lactate, d-lactate/l-lactate ratio and d-lactate/total lactate ratio in plasma as potential early biomarkers of bacteraemia on a strictly biological standpoint. Methods: A total of 228 plasma specimens were collected from patients who had confirmed bacteraemia (n = 131) and healthy outpatients (n = 97). Specific l-lactate and d-lactate analyses were performed using enzymatic assays and analytical performances of d-lactate, d-lactate/total lactate and d-lactate/l-lactate ratios for the diagnosis of bacteraemia were assessed. Results: A preliminary in vitro study confirmed that all strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were able to produce d-lactate at significant levels. In patients, plasma d-lactate level was the most specific biomarker predicting a bacteraemia profile with a specificity and predictive positive value of 100% using a cut-off of 131 µmol.L-1. However, sensitivity and negative predictive value were rather low, estimated at 31% and 52%, respectively. d-lactate displayed an Area Under Receiver Operating Characteristic (AUROC) curve of 0.696 with a P value < 0.0001. There was no difference of d-lactate levels between BCs bottles positive for Gram-positive or Gram-negative bacteria (p = 0.55). Conclusion: d-lactate shows promise as a specific early biomarker of bacterial metabolism. The development of rapid automated assays could raise clinical applications for infectious diseases diagnosis including early bacteraemia prediction.

[Troponin T cardiac analysis: clinical cases of the limits of its cardiospecificity]. / Illustrations cliniques d'un manque de cardiospécificité du dosage de troponine T hypersensible.

INTRODUCTION: Myositis are systemic diseases, in which heart damage is possible. Cardiac troponin T is often found to be defective to detect cardiac involvement. OBSERVATION: We report cases of two patients with a myositis. Diagnosis was retained based on muscle pain, increase in serum creatinine kinase, and inflammatory muscle damage on MRI. Histology confirmed the diagnosis for one of the two patients. Cardiac troponin T was measured in both patients, to detect myocardial involvement. Despite a serum elevation of this marker, cardiological assessment remained negative (electrocardiogram, cardiac ultrasound, cardiac MRI). Cardiac troponin I was normal in serum because of the absence of correlation with peripheral muscle involvement. CONCLUSION: Cardiac troponin T is correlated with muscle involvement in patients with myositis. Cardiac troponin I should be preferred because of a better specificity.

Redefining Therapeutic Drug Monitoring of Tacrolimus in Patients Undergoing Liver Transplantation: A Target Trough Concentration of 4-7 ng/mL During the First Month After Liver Transplantation is Safe and Improves Graft and Renal Function.

BACKGROUND: Currently, the recommended tacrolimus (TAC) trough level (Cmin) after liver transplantation (LT) is 6-10 ng/mL (when associated in triple immunosuppressive therapy). However, few studies have achieved the lower limit of this range, especially below 7 ng/mL. This study evaluated the efficacy of a target TAC Cmin of 4-7 ng/mL after LT. METHODS: Of 1677 LTs performed between 2002 and 2017, 904 LT cases were analyzed. The cases were categorized into the following 3 groups and compared: low- (n = 247, 27.3%), intermediate- (n = 344, 37.9%), and high-exposure groups (n = 313, 34.5%) with TAC Cmin of 4-7 ng/mL, 7-10 ng/mL, and >10 ng/mL, respectively. In addition, propensity score matching was performed to reduce heterogeneity and population bias. RESULTS: At months 1 and 3, when compared with the 2 other groups, the low-exposure group had similar grafts (P = 0.75) and patient (P = 0.77) survival, but lower alanine aminotransferase (P < 0.001), bilirubin (P < 0.001), international normalized ratio (P = 0.046), and creatinine (P < 0.001) levels. After propensity score matching, the bilirubin (P < 0.001) and creatinine (P = 0.001) levels in the low-exposure group still improved at months 3, but the graft (P = 0.86) and patient (P = 0.99) survival were still similar. CONCLUSIONS: A TAC Cmin of 4-7 ng/mL seems safe and capable of improving graft and kidney function. This finding should be confirmed in a prospective randomized trial.

Curcuma decreases serum hepcidin levels in healthy volunteers: a placebo-controlled, randomized, double-blind, cross-over study.

Hepcidin, secreted by hepatocytes, controls iron metabolism by limiting iron egress in plasma. Hepcidin is upregulated during inflammation through the activation of the signal transducer and activator of transcription 3 (STAT3) transduction pathway, which decreases iron bioavailability and may explain the anemia of chronic inflammatory disease. In vitro, it has been shown that curcumin can decrease hepcidin synthesis by decreasing STAT3 activity. We conducted a proof-of-concept study to assess the effect of curcuma on hepcidin synthesis in human. This was a placebo-controlled, randomized, double-blind, cross-over, two-period study performed in 18 healthy male volunteers. Subjects received a single oral dose of 6 g curcuma containing 2% of curcumin or placebo. Serum hepcidin and iron parameters were assessed repeatedly until 48 h after dosing. When compared with a placebo curcuma decreased hepcidin levels significantly at 6 h (-19%, P = 0.004), 8 h (-17%, P = 0.009), and 12 h (-17%, P = 0.007) and tended to decrease hepcidin at 24 h (-15%, P = 0.076). Curcuma also significantly increased serum ferritin levels at 6 and 8 h (+7% for both times, P = 0.018, 0.030, respectively) and had no effects on serum iron, transferrin, and transferrin saturation. This pilot study showed that curcuma decreases serum hepcidin levels in human and supports the idea that curcuma could be useful in treating hepcidin overproduction during inflammatory processes. Confirmatory studies in patients with chronic inflammation are now required to determine the optimal dose and therapeutic scheme of curcuma.

Sunitinib combined with angiotensin-2 type-1 receptor antagonists induces more necrosis: a murine xenograft model of renal cell carcinoma.

BACKGROUND: Angiotensin-2 type-1 receptor antagonists not are only antihypertensive drugs but also can inhibit VEGF production. We hypothesised that adding telmisartan to sunitinib could potentiate the antiangiogenic effects. MATERIAL AND METHODS: 786-O cell lines were injected in nude mice. After tumor development, mice were divided into 4 groups: the first was the control group (DMSO), the second group was treated with sunitinib alone, the third group was treated with telmisartan alone, and the fourth group was treated with the combination. Drugs were orally administered every day for four weeks. Animals were sacrificed after treatment. Blood and tumor tissues were collected for analysis by immunohistochemistry, Western Blot, and ELISA methods. RESULTS: All animals developed a ccRCC and ten in each group were treated. Using a kinetic model, tumors tended to grow slower in the combination group compared to others (P = 0.06). Compared to sunitinib alone, the addition of telmisartan significantly increased tissue necrosis (P = 0.038). Central microvascular density decreased (P = 0.0038) as well as circulating VEGF (P = 0.003). There was no significant variation in proliferation or apoptosis markers. CONCLUSION: The combination of sunitinib and telmisartan revealed an enhancement of the blockage of the VEGF pathway on renal tumor resulting in a decrease in neoangiogenesis and an increase in necrosis.

Differentiation of human placental BeWo cells by the environmental contaminant benzo(a)pyrene.

Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (BaP) are widely-distributed environmental contaminants known to exert toxic effects in various tissues, including placenta. PAHs have notably been shown to inhibit proliferation of trophoblastic cells. The present study was designed to determine whether PAHs can concomitantly affect differentiated functions of trophoblastic cells. BaP was found to induce expression and secretion of ß-human chorionic gonadotropin (ß-hCG) in human trophoblastic BeWo cells. The PAH also increased mRNA expressions of other trophoblastic differentiation markers, including those of the steroid metabolism enzymes CYP19A1 and HSD11B2 and of the fusogenic protein syncytin-2; in parallel, it triggered syncytialisation of BeWo cells. BaP-mediated ß-hCG and syncytin-2 up-regulation was prevented by co-treatment by the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or by knocking-down AhR expression through siRNA transfection. However, the potent AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) failed to induce expression of ß-hCG and syncytin-2, indicating that activation of the AhR pathway, known to be implicated in most, if not all, effects of PAHs, was required, but not sufficient. Interestingly, the p53 signaling pathway was activated by BaP, but not by TCDD, in BeWo cells and co-treatment by the p53 inhibitor pifithrin-α or siRNAs-mediated silencing of p53 prevented up-regulation of ß-hCG and syncytin-2 induced by BaP. Taken together, these data demonstrate that BaP induces differentiation of placental trophoblastic BeWo cells in an AhR- and p53-dependent manner.

Bioinformatic software for cerebrospinal fluid spectrophotometry in suspected subarachnoid haemorrhage.

BACKGROUND: Diagnosis of subarachnoid haemorrhage (SAH) is firstly based on imaging and secondly on spectrophotometry. Bilirubin may be detected in the cerebrospinal fluid (CSF) for up to two weeks after SAH. CSF pigment analysis is commonly performed according to the Chalmers manual technique but may be prone to operator error. We propose an online software solution, based on the United Kingdom National External Quality Assessment Service (UKNEQAS) recommendations, to support the interpretation of CSF pigment analysis. METHODS: Based on the manual Chalmers technique, we have developed a web application (in Personal Home Page language including JpGraph module and an Oracle database(®)) that enables the calculation of net oxyhaemoglobin absorbance and net bilirubin absorbance. It uses data from the CSF spectrophotometry, CSF and serum protein concentrations, and serum bilirubin concentration to provide an interpretation based on the NEQAS decision tree. The application was retrospectively validated using the spectra from 350 patients, previously analysed by the manual method. RESULTS: In total, 91.1% interpretations from spectra analysed with the web application were in accordance with the results obtained manually. The 8.9% discordant results were mostly related to an incorrect interpretation using the manual technique. CONCLUSIONS: The software developed in our laboratory to interpret CSF pigment analysis results is a precise, robust and useful tool that allows reproducible conclusions to be drawn. This software is available through a web interface.

PPARγ is functionally expressed in clear cell renal cell carcinoma.

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have been demonstrated to exert an inhibitory effect on cell growth in several tumor models, including clear cell renal cell carcinoma (CCRCC). PPARγ has therefore been proposed to be a potential therapeutic target. Thus, the PPARγ gene must be expressed and not altered in cancer cells. We have therefore analyzed tumor specimens collected from 63 patients with CCRCC who underwent partial or total nephrectomy. The multiplex ligation-dependent probe amplification (MLPA) assay was used to detect deletions in the PPARγ gene. The majority of the tumors (48/63; 76.2%) did not present alterations. Two samples (3.2%) presented a deletion of the non-coding exon A1. Nine samples (14.3%) showed large heterozygous deletions in chromosome 3p including PPARγ. Potential mutations were analyzed by DNA sequencing of the 6 coding exons of the PPARγ gene. No mutation was found in exons 1-5. In exon 6, a silent polymorphism was detected in 14 samples (22.2%). CCRCC were found to express the PPARγ1 isoform. The expression level of PPARγ was measured by real-time quantitative PCR. A significantly reduced transcript level was associated with an elevated Fuhrman grade. Finally, we analyzed the expression of angiopoietin-like 4, a known PPARγ target gene, in CCRCC cell lines cultured in the presence of rosiglitazone, a PPARγ agonist. A strong induction was found in the 3 cell lines tested, indicating that PPARγ is functional in all these cell lines. In conclusion, we show here that PPARγ is expressed and functional in CCRCC, prerequisites for being a potential target for CCRCC treatment.

Determination of daptomycin in human plasma by liquid chromatography-tandem mass spectrometry. Clinical application.

BACKGROUND: Daptomycin is a recently developed cyclic lipopeptide antibiotic active against most Gram-positive pathogens including vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus. To optimize treatment efficacy and safety, especially in patients undergoing multiple drug regimens and/or co-morbidities, a specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of daptomycin in plasma. METHODS: A C18 column was used for separation, with a mobile phase initially consisting of 0.1% formic acid, water, and acetonitrile (ACN) in a linear gradient from 20% to 70%. After protein precipitation with ACN, the clear upper layer was diluted in water:ACN (50:50, v/v) before injection. Detection was performed using an electrospray ionization technique. MS/MS transitions, monitored in the positive ion mode were m/z 811.1 → m/z 313.1 for daptomycin, and m/z 609.4 → m/z 194.9 for reserpine, used as internal standard. RESULTS: Elution of daptomycin and reserpine occurred at 4.5 and 3.9 min, respectively. The method was validated over a range of concentrations from 1 mg/L to 120 mg/L. The assay met recommended acceptance criteria: coefficients of variation were <6.3% and <7.4%, and accuracies were between -5.9% and +11.2% and between -3.5% and +3.7%, for intra- and inter-day validations, respectively. CONCLUSIONS: This method appears well-adapted to routine hospital practice for therapeutic drug monitoring of daptomycin considering its time of analysis, range of concentrations measured, precision and accuracy.