Cytochrome P450 2D6, 3A4 and 3A5 are involved in the metabolism of many drugs. These enzymes have a genetic polymorphism responsible for different metabolic phenotypes. They play a role in the ...metabolism of clomiphene citrate (CC), which is used to induce ovulation. Response to CC treatment is variable, and no predictive factors have thus far been identified.
To study a possible link between the cytochrome P450 2D6, 3A4 and 3A5 polymorphisms and clinical response to CC.
Seventy-seven women with anovulatory Polycystic Ovarian Syndrome (PCOS) treated with CC were included which determined their cytochrome P450 2D6, 3A4 and 3A5 genotypes and used the results to predict ovarian response to this drug. Predicted responses based on the cytochrome genotypes were compared with the observed clinical responses using the calculation of a weighted Kappa coefficient.
Number of dominant follicles assessed by ultrasound at the end of the follicular phase and confirmation of ovulation by blood progesterone assay in the luteal phase.
Concordance between the predicted and observed responses for the combination of the three cytochromes was 36.71%, with a negative Kappa coefficient (K = -0.0240), which corresponds to a major disagreement. Similarly, for predictions based on the cytochrome P450 2D6 genotype alone, only 39.24% of predictions were verified (coefficient K = -0.0609).
The genetic polymorphism of cytochromes P450 2D6, 3A4 and 3A5 does not appear to influence clinical response to CC used to induce ovulation in anovulatory PCOS women.
Anti-Saccharomyces cerevisiae antibodies (ASCAs) are present in 50-60% of patients with Crohn's disease (CD) and in 20-25% of their healthy relatives (HRs). The yeast, Candida albicans, has been ...shown to generate ASCAs, but the presence of C. albicans in the digestive tract of CD patients and their HRs has never been investigated. Therefore, we studied C. albicans carriage in familial CD and its correlation with ASCAs.
Study groups consisted of 41 CD families composed of 129 patients and 113 HRs, and 14 control families composed of 76 individuals. Mouth swabs and stool specimens were collected for isolation, identification, and quantification of yeasts. Serum samples were collected for detection of ASCAs and anti-C. albicans mannan antibodies (ACMAs).
C. albicans was isolated significantly more frequently from stool samples from CD patients (44%) and their HRs (38%) than from controls (22%) (P<0.05). The prevalence of ACMAs was similar between CD patients, their HRs, and controls (22, 19, and 21%, respectively, P=0.845), whereas the prevalence of ASCAs was significantly increased in CD families (72 and 34% in CD and HRs, respectively, in contrast to 4% in controls, P<0.0001). AMCA levels correlated with C. albicans colonization in all populations. ASCA levels correlated with C. albicans colonization in HRs but not in CD patients.
CD patients and their first-degree HRs are more frequently and more heavily colonized by C. albicans than are controls. ASCAs correlate with C. albicans colonization in HRs but not in CD. In HRs, ASCAs could result from an altered immune response to C. albicans. In CD, a subsequent alteration in sensing C. albicans colonization could occur with disease onset.
Previously, the in vitro growth of cancer stem cells in the form of tumor spheres from five different brain cancer cell lines was found to be methionine-dependent. As this earlier work indicated that
..., a folate-dependent mitochondria aldehyde dehydrogenase gene, is upregulated in glioblastoma stem cells, we invalidated this gene using CRISPR-cas 9 technique in this present work. We reported here that this invalidation was effective in U251 glioblastoma cells, and no cas9 off target site could be detected by genome sequencing of the two independent knockout targeting either exon I or exon III. The knockout of
gene in U251 cells rendered the growth of the cancer stem cells of U251 methionine independent. In addition, a much higher ROS (reactive oxygen radicals) level can be detected in the knockout cells compared to the wild type cells. Our evidence here linked the excessive ROS level of the knockout cells to reduced total cellular NADPH. Our evidence suggested also that the cause of the slower growth of the knockout turmor sphere may be related to its partial differentiation.
Irinotecan is a major drug in the treatment of advanced colorectal cancer. Its active form is the SN38 metabolite, which is cleared by the biliary route after glucuronidation by uridine ...diphosphate–glucuronosyltransferase 1A1 (UGT1A1). UGT1A1 activity exhibits a wide intersubject variability, in part related to UGT1A1 gene polymorphisms. The present review on the impact of the deficient UGT1A1*28 variant on irinotecan efficacy and toxicity was produced by a French joint workgroup comprising the Group of Clinical Onco‐pharmacology (GPCO‐Unicancer) and the National Pharmacogenetics Network (RNPGx). It clearly emerges that for irinotecan doses at least equal to 180 mg/m2, patients homozygous for the UGT1A1*28 allele are at increased risk of developing hematological and/or digestive toxicities. Irinotecan dose reduction is thus recommended in homozygous *28/*28 patients. In addition, this personalized medicine strategy aims to secure high‐dose irinotecan administration (≥240 mg/m2) that have proven to be safe in homozygous *1/*1 patients only. The clinical relevance of this test is discussed in terms of treatment efficacy improvement, as increasing the irinotecan dose appears to be safe in patients not bearing a deficient allele. Best execution practices, cost‐effectiveness, and result interpretation are discussed with the aim of facilitating the implementation of this analysis in clinical practice. The existence of networks of laboratories performing this test in routine hospital treatment, as in France, offers the prospect of widespread screening, thus guaranteeing equal access to safe treatment and optimized therapy for patients receiving irinotecan‐based therapy in advanced colorectal cancer.
Background
Tramadol is a synthetic, centrally acting analgesic for the treatment of moderate to severe pain. The marketed tramadol is a racemic mixture containing 50% (+)tramadol and 50% (−)tramadol ...and is mainly metabolized to O-desmethyltramadol (M1) by the cytochrome P450 CYP2D6. Tramadol is generally considered to be devoid of any serious adverse effects of traditional opioid receptor agonists, such as respiratory depression and drug dependence.
Case report
A 22-year-old Caucasian female patient was admitted to our ICU in refractory cardiac arrest requiring extracorporeal membrane oxygenation. This aggressive support allowed resolution of multi-organ dysfunction syndrome. Repeated blood analyses using liquid chromatography-tandem mass spectrometry confirmed high concentrations of both tramadol and its main metabolite O-desmethyltramadol. Genotyping of CYP2D6 revealed the patient to be heterozygous for a duplicated wild-type allele, predictive of a CYP2D6 ultrarapid metabolizer (UM) phenotype, confirmed by calculation of the tramadol/M1 (MR1) metabolic ratio at all time points.
Discussion
We here report a case of near-fatal isolated tramadol cardiotoxicity. Because of the inhibition of norepinephrine reuptake, excessive blood epinephrine levels in this CYP2D6R UM patient following excessive tramadol ingestion could explain the observed strong myocardial stunning. This patient admitted intermittent tramadol consumption to gain a “high” sensation. In patients with excessive morphinomimetic effects, levels of tramadol and its main metabolite M1could be measured, ideally combined with CYP2D6 genotyping, to identify individuals at risk of tramadol-related cardiotoxicity. Tramadol treatment could be optimized in these at-risk individuals, consequently improving patient outcome and safety.
Background. The effect of potentially relevant genetic polymorphisms, CYP3A5 6986A>G and ABCB1 3435C>T, on Tacrolimus pharmacokinetics and graft clinical outcome was investigated in donor and ...recipient DNA samples from 209 kidney transplant patients.
Methodology/principal findings. The mean follow-up was 21.8 ± 9 months. The Tacrolimus dose, trough blood concentrations (C0) and C0/dose ratio were only statistically correlated with the recipient CYP3A5 genotype. CYP3A5 and ABCB1 genotypes appeared to have no influence on the incidence of Biopsy Proven Acute Rejection and Delayed Graft Function. Renal function was not affected by CYP3A5 and ABCB1 genotypes. Histological evaluation of biopsies revealed also no significant association between Tacrolimus toxicity features and donor or recipient CYP3A5 and ABCB1 polymorphisms. Tacrolimus sparing appeared to be independent of CYP3A5 and ABCB1 genotypes.
Conclusions/significance. Recipient CYP3A5 6986A>G polymorphism explains part of the interindividual variability of the pharmacokinetics of Tacrolimus. The clinical outcome at 2-year follow-up does not appear to be related to the donor or recipient CYP3A5 6986A>G and/or ABCB1 3435C>T polymorphisms.
Actually, about 2000 sequence variations have been documented in the CFTR gene requiring extensive and multi-step genetic testing in the diagnosis of cystic fibrosis and CFTR-related disorders. We ...present a two phases study, with validation and performance monitoring, of a single experiment methodology based on multiplex PCR and high throughput sequencing that allows detection of all variants, including large rearrangements, affecting the coding regions plus three deep intronic loci.
A total of 340 samples, including 257 patients and 83 previously characterized control samples, were sequenced in 17 MiSeq runs and analyzed with two bioinformatic pipelines in routine diagnostic conditions. We obtained 100% coverage for all the target regions in every tested sample.
We correctly identified all the 87 known variants in the control samples and successfully confirmed the 62 variants identified among the patients without observing false positive results. Large rearrangements were identified in 18/18 control samples. Only 17 patient samples showed false positive signals (6.6%), 12 of which showed a borderline result for a single amplicon. We also demonstrated the ability of the assay to detect allele specific dropout of amplicons when a sequence variation occurs at a primer binding site thus limiting the risk for false negative results.
We described here the first NGS workflow for CFTR routine analysis that demonstrated equivalent diagnostic performances compared to Sanger sequencing and multiplex ligation-dependent probe amplification. This study illustrates the advantages of NGS in term of scalability, workload reduction and cost-effectiveness in combination with an improvement of the overall data quality due to the simultaneous detection of SNVs and large rearrangements.
Isoniazid is the most widely used anti-tuberculosis agent, yet it may lead to life-threatening complications.
Here we report the case of a chronic hemodialysis patient who developed severe ...encephalopathy after the start of isoniazid. Blood levels of isoniazid were elevated, and acetyl-isoniazid over isoniazid ratio was decreased 3 h after intake of the medication, suggesting that a slow acetylator phenotype may have contributed to drug toxicity, in addition to pyridoxal phosphate removal by dialysis. This hypothesis was confirmed by sequencing of NAT2, the gene responsible for isoniazid elimination, and identification of NAT2 polymorphisms compatible with a slow acetylator phenotype. Isoniazid withdrawal along with supplementation using high doses of pyridoxine successfully reversed the drug toxicity. Isoniazid toxicity occurs in populations at risk, including patients with chronic kidney failure or NAT2 polymorphisms, who have a disturbed metabolism of pyridoxine or isoniazid, respectively, and those on renal replacement therapies, in whom pyridoxal phosphate - the active metabolite of pyridoxine - is inadvertently removed by dialysis.
Physicians should be aware of the increased risk of isoniazid toxicity in patients on dialysis and in those with a slow acetylator phenotype conferred by NAT2 polymorphisms. Adaptation of prescription - either with higher doses of pyridoxine or decreased doses of isoniazid, respectively - has been suggested to reduce the risk of potentially life-threatening toxicity of isoniazid.
Tacrolimus is metabolized by cytochrome P450 (CYP) 3A5. The objective of this study was to investigate the influence of the genetic polymorphism of CYP3A5 on the pharmacokinetics of a new ...modified-release, once-daily formulation of tacrolimus (Advagraf®) after a switch from the immediate-release formulation (Prograf®).
This was a prospective, single-centre, open-label study in stable kidney transplant recipients. Seventeen 'expressor' patients (CYP3A5*1/*3 or *1/*1) were matched to 15 'non-expressor' patients (CYP3A5*3/*3). Exposure variables (concentrations and area under the blood concentration-time curve from 0 to 24 hours AUC(24)) were obtained before and 15 days after the switch. Delay since grafting was similar for both groups of patients (expressors: 49 ± 24 months; non-expressors: 45 ± 22 months).
During administration of tacrolimus as Prograf® or Advagraf®, the mean tacrolimus daily dose was significantly higher and the dose-adjusted AUC(24) was significantly lower in the expressor group. Following the switch to Advagraf®, there was a significant decrease in the dose-adjusted AUC(24) for both non-expressor (5910 ± 3019 vs 5334 ± 2668 ng·h/mL per mg/kg/day; p = 0.041) and expressor patients (3701 ± 1409 vs 3273 ± 1372 ng·h/mL per mg/kg/day; p = 0.03). In the non-expressor group, mean blood trough concentration (C(0)) was comparable for both formulations while it decreased significantly in the expressor group after the switch (8.2 ± 2.2 vs 6.3 ± 2.5 ng/mL; p = 0.02). However, a good correlation between AUC(24) and C(0) was observed for both Advagraf® and Prograf® regardless of CYP3A5 genotype.
Tacrolimus exposure significantly decreases after a switch from Prograf® to Advagraf®, on a milligram-for-milligram basis, in CYP3A5 expressor recipients. Consequently, these patients should be carefully monitored.
The paper describes the development of an inductively coupled plasma mass spectrometry (ICP MS) method for multitrace element determination in dried blood spots (DBSs). The analytical conditions were ...optimized using Seronorm™ L-3 and L-1 Certified Reference Materials. The best results were obtained by sampling blood drops on a decontaminated PVDF filter membrane. After drying under metal-free conditions, the DBSs underwent acidic digestion and were analyzed with ICP MS. The method was then validated for As, Cd, Cu, Pb, Mo, Se and Zn. Using a matrix-matched calibration curve, the recovery levels ranged from 96% to 117%. The repeatability and reproducibility were generally below 15%. Limits of quantification ranging from 0.5 to 50μg/L. In order to investigate the analytical procedure under real sampling conditions, the results obtained from DBSs and liquid blood aliquots (less subject to contamination) from two adult subjects were compared.
PDF
