Carboxylesterase 1-Based Drug-Drug Interaction Potential of Remimazolam: In-Vitro Studies and Literature Review.

BACKGROUND: The ultra-short-acting benzodiazepine remimazolam, approved for procedural sedation and general anesthesia, is inactivated by carboxylesterase 1 (CES1). OBJECTIVE: Remimazolam´s involvement in CES1-mediated drug-drug interactions (DDIs) was investigated. METHODS: Possible interactions of remimazolam were studied in co-exposure experiments with eleven different drugs. Further, substrates and inhibitors of CES1, identified in the literature, were evaluated for possible in-vivo inhibition using pharmacokinetic and Ki or IC50 values. Compounds with only one published inhibitory concentration and CES1 substrates lacking inhibition data were assigned conservative Ki values. RESULTS: In human liver homogenates and/or blood cells, remimazolam showed no significant inhibition of esmolol and landiolol metabolism, which, in turn, at up to 98 and 169 µM, respectively, did not inhibit remimazolam hydrolysis by human liver homogenates. In human liver S9 fractions, IC50 values ranged from 0.69 µM (simvastatin) and 57 µM (diltiazem) to > 100 µM (atorvastatin) and, for the remaining test items (bupropion, carvedilol, nelfinavir, nitrendipine, and telmisartan), they ranged from 126 to 658 µM. Remifentanil was ineffective even at 1250 µM. Guidance-conforming evaluation revealed no relevant drug-drug interactions with remimazolam via CES1. The algorithm-based predictions were consistent with human study data. Among CES1 inhibitors and substrates identified in the literature, only dapsone and rufinamide were found to be possible in-vivo inhibitors of remimazolam metabolism. CONCLUSION: Data and analyses suggest a very low potential of remimazolam for pharmacokinetic DDIs mediated by CES1. The theoretical approach and compiled data are not specific to remimazolam and, hence, applicable in the evaluation of other CES1 substrates.

Genetic variants of ABCB1 and CES1 genes on dabigatran metabolism in the Kazakh population.

Background: Allelic variants of genes encoding enzymes of the esterase system (CES1) and P-glycoprotein (ABCB1) can change the metabolism and pharmacokinetics of dabigatran. Therefore, they act as determining factors in the development of side effects, especially bleeding. We analyzed the genotype-phenotype relationship of ABCB1 (rs1045642, rs4148738, rs2032582, and rs1128503) and CES1 (rs8192935, rs71647871, and rs2244613) polymorphisms in patients with atrial fibrillation who had been treated with dabigatran. Methods: A total of 150 patients were recruited for this study. TaqMan technology was used for SNP genotyping. Results: Patients with the rs2244613 GG genotype had a lower concentration (55.27 ± 34.22 ng/ml) compared to those with the TT genotype (63.33 ± 52.25 ng/ml) (additive model, P = 0.000). Individuals with the rs8192935 AA genotype had a lower concentration (52.72 ± 30.45 ng/ml) compared to those with the GG genotype (79.78 ± 57 ng/ml) (additive model, P = 0.001). The APTT values among the different genotypes of the ABCB1 SNPs, rs4148738 and rs1045642, were significantly different (P = 0.035 and P = 0.024, respectively). Conclusion: Our research demonstrates that the CES1 polymorphisms, rs8192935 and rs2244613, are associated with the pharmacodynamics and pharmacokinetics of dabigatran in the Kazakh subpopulation.

New insight on porcine carboxylesterases expression and activity in lung tissues.

Over the course of the last twenty years, there has been a growing recognition of the pig's potential as a valuable model for studying human drug metabolism. This study aimed to investigate the expression, enzymatic activity, inhibitory susceptibility, and cellular localization of carboxylesterases (CES) in porcine lung tissue not yet explored. Our results showed that CESs hydrolysis activity followed Michaelis-Menten kinetics in both cytosolic and microsomal fractions of porcine lung tissues (N = 8), with comparable hydrolysis rates for tested substrates, namely 4-nitrophenyl acetate (pNPA), 4-methylumbelliferyl acetate (4-MUA), and fluorescein diacetate (FD). We also determined the CESs hydrolysis activity in a representative sample of the porcine liver that, as expected, displayed higher activity than the lung ones. The study demonstrated variable levels of enzyme activities and interindividual variability in both porcine lung fractions. Inhibition studies used to assess the CESs' involvement in the hydrolysis of pNPA, 4-MUA, and FD suggested that CESs may be the enzymes primarily involved in the metabolism of ester compounds in the pig lung tissue. Overall, this study provides insight into the distribution and diversity of CES isoforms involved in substrate hydrolysis across different cellular fractions (cytosol and microsomes) in porcine lungs.

Gene polymorphism as a cause of hemorrhagic complications in patients with non-valvular atrial fibrillation treated with oral vitamin K-independent anticoagulants.

Atrial fibrillation (AF) accounts for 40% of all cardiac arrhythmias and is associated with a high risk of stroke and systemic thromboembolic complications. Dabigatran, rivaroxaban, apixaban, and edoxaban are direct oral anticoagulants (DOACs) that have been proven to prevent stroke in patients with non-valvular AF. This review summarizes the pharmacokinetics, pharmacodynamics, and drug interactions of DOACs, as well as new data from pharmacogenetic studies of these drugs. This review is aimed at analyzing the scientific literature on the gene polymorphisms involved in the metabolism of DOACs. We searched PubMed, Cochrane, Google Scholar, and CyberLeninka (Russian version) databases with keywords: 'dabigatran', 'apixaban', 'rivaroxaban', 'edoxaban', 'gene polymorphism', 'pharmacogenetics', 'ABCB1', 'CES1', 'SULT1A', 'ABCG2', and 'CYP3A4'. The articles referred for this review include (1) full-text articles; (2) study design with meta-analysis, an observational study in patients taking DOAC; and (3) data on the single-nucleotide polymorphisms and kinetic parameters of DOACs (plasma concentration), or a particular clinical outcome, published in English and Russian languages during the last 10 years. The ages of the patients ranged from 18 to 75 years. Out of 114 reviewed works, 24 were found eligible. As per the available pharmacogenomic data, polymorphisms affecting DOACs are different. This may aid in developing individual approaches to optimize DOAC pharmacotherapy to reduce the risk of hemorrhagic complications. However, large-scale population studies are required to determine the dosage of the new oral anticoagulants based on genotyping. Information on the genetic effects is limited owing to the lack of large-scale studies. Uncovering the mechanisms of the genetic basis of sensitivity to DOACs helps in developing personalized therapy based on patient-specific genetic variants and improves the efficacy and safety of DOACs in the general population.

Gene polymorphism as a cause of hemorrhagic complications in patients with non-valvular atrial fibrillation treated with oral vitamin K-independent anticoagulantsAtrial fibrillation (AF) accounts for 40% of all cardiac arrhythmias and is associated with a high risk of stroke and systemic thromboembolic complications. Dabigatran, rivaroxaban, apixaban, and edoxaban are direct oral anticoagulants (DOACs) that have been proven to prevent stroke in patients with non-valvular AF. This review summarizes the pharmacokinetics, pharmacodynamics, and drug interactions of DOACs, as well as new data from pharmacogenetic studies of these drugs.

Regulation of carboxylesterases and its impact on pharmacokinetics and pharmacodynamics: an up-to-date review.

INTRODUCTION: Carboxylesterase 1 (CES1) and carboxylesterase 2 (CES2) are among the most abundant hydrolases in humans, catalyzing the metabolism of numerous clinically important medications, such as methylphenidate and clopidogrel. The large interindividual variability in the expression and activity of CES1 and CES2 affects the pharmacokinetics (PK) and pharmacodynamics (PD) of substrate drugs. AREAS COVERED: This review provides an up-to-date overview of CES expression and activity regulations and examines their impact on the PK and PD of CES substrate drugs. The literature search was conducted on PubMed from inception to January 2024. EXPERT OPINION: Current research revealed modest associations of CES genetic polymorphisms with drug exposure and response. Beyond genomic polymorphisms, transcriptional and posttranslational regulations can also significantly affect CES expression and activity and consequently alter PK and PD. Recent advances in plasma biomarkers of drug-metabolizing enzymes encourage the research of plasma protein and metabolite biomarkers for CES1 and CES2, which could lead to the establishment of precision pharmacotherapy regimens for drugs metabolized by CESs. Moreover, our understanding of tissue-specific expression and substrate selectivity of CES1 and CES2 has shed light on improving the design of CES1- and CES2-activated prodrugs.

Interplay of Ritonavir-Boosted Oral Cabazitaxel with the Organic Anion-Transporting Polypeptide (OATP) Uptake Transporters and Carboxylesterase 1 in Mice.

Intravenously administered chemotherapeutic cabazitaxel is used for palliative treatment of prostate cancer. An oral formulation would be more patient-friendly and reduce the need for hospitalization. We therefore study determinants of the oral pharmacokinetics of cabazitaxel in a ritonavir-boosted setting, which reduces the CYP3A-mediated first-pass metabolism of cabazitaxel. We here assessed the role of organic anion-transporting polypeptides (OATPs) in the disposition of orally boosted cabazitaxel and its active metabolites, using the Oatp1a/b-knockout and the OATP1B1/1B3-transgenic mice. These transporters may substantially affect plasma clearance and hepatic and intestinal drug disposition. The pharmacokinetics of cabazitaxel and DM2 were not significantly affected by Oatp1a/b and OATP1B1/1B3 activity. In contrast, the plasma AUC0-120 min of DM1 in Oatp1a/b-/- was 1.9-fold (p < 0.05) higher than that in wild-type mice, and that of docetaxel was 2.4-fold (p < 0.05) higher. We further observed impaired hepatic uptake and intestinal disposition for DM1 and docetaxel in the Oatp-ablated strains. None of these parameters showed rescue by the OATP1B1 or -1B3 transporters in the humanized mouse strains, suggesting a minimal role of OATP1B1/1B3. Ritonavir itself was also a potent substrate for mOatp1a/b, showing a 2.9-fold (p < 0.0001) increased plasma AUC0-120 min and 3.5-fold (p < 0.0001) decreased liver-to-plasma ratio in Oatp1a/b-/- compared to those in wild-type mice. Furthermore, we observed the tight binding of cabazitaxel and its active metabolites, including docetaxel, to plasma carboxylesterase (Ces1c) in mice, which may complicate the interpretation of pharmacokinetic and pharmacodynamic mouse studies. Collectively, these results will help to further optimize (pre)clinical research into the safety and efficacy of orally applied cabazitaxel.

An in vitro evaluation of kratom (Mitragyna speciosa) on the catalytic activity of carboxylesterase 1 (CES1).

Kratom, (Mitragyna Speciosa Korth.) is a plant indigenous to Southeast Asia whose leaves are cultivated for a variety of medicinal purposes and mostly consumed as powders or tea in the United States. Kratom use has surged in popularity with the lay public and is currently being investigated for possible therapeutic benefits including as a treatment for opioid withdrawal due to the pharmacologic effects of its indole alkaloids. A wide array of psychoactive compounds are found in kratom, with mitragynine being the most abundant alkaloid. The drug-drug interaction (DDI) potential of mitragynine and related alkaloids have been evaluated for effects on the major cytochrome P450s (CYPs) via in vitro assays and limited clinical investigations. However, no thorough assessment of their potential to inhibit the major hepatic hydrolase, carboxylesterase 1 (CES1), exists. The purpose of this study was to evaluate the in vitro inhibitory potential of kratom extracts and its individual major alkaloids using an established CES1 assay and incubation system. Three separate kratom extracts and the major kratom alkaloids mitragynine, speciogynine, speciociliatine, paynantheine, and corynantheidine displayed a concentration-dependent reversible inhibition of CES1. The experimental Ki values were determined as follows for mitragynine, speciociliatine, paynantheine, and corynantheidine: 20.6, 8.6, 26.1, and 12.5 µM respectively. Speciociliatine, paynantheine, and corynantheidine were all determined to be mixed-type reversible inhibitors of CES1, while mitragynine was a purely competitive inhibitor. Based on available pharmacokinetic data, determined Ki values, and a physiologically based inhibition screen mimicking alkaloid exposures in humans, a DDI mediated via CES1 inhibition appears unlikely across a spectrum of doses (i.e., 2-20g per dose). However, further clinical studies need to be conducted to exclude the possibility of a DDI at higher and extreme doses of kratom and those who are chronic users.

The Distribution of the Genotypes of ABCB1 and CES1 Polymorphisms in Kazakhstani Patients with Atrial Fibrillation Treated with DOAC.

Nowadays, direct oral anticoagulants (DOACs) are the first-line anticoagulant strategy in patients with non-valvular atrial fibrillation (NVAF). We aimed to identify the influence of polymorphisms of the genes encoding P-glycoprotein (ABCB1) and carboxylesterase 1 (CES1) on the variability of plasma concentrations of DOACs in Kazakhstani patients with NVAF. We analyzed polymorphisms rs4148738, rs1045642, rs2032582 and rs1128503 in ABCB1 and rs8192935, rs2244613 and rs71647871 CES1 genes and measured the plasma concentrations of dabigatran/apixaban and biochemical parameters in 150 Kazakhstani NVAF patients. Polymorphism rs8192935 in the CES1 gene (p = 0.04), BMI (p = 0.01) and APTT level (p = 0.01) were statistically significant independent factors of trough plasma concentration of dabigatran. In contrast, polymorphisms rs4148738, rs1045642, rs2032582 and rs1128503 in ABCB1 and rs8192935, rs2244613 and rs71647871 CES1 genes did not show significant influence on plasma concentrations of dabigatran/apixaban drugs (p > 0.05). Patients with GG genotype (138.8 ± 100.1 ng/mL) had higher peak plasma concentration of dabigatran than with AA genotype (100.9 ± 59.6 ng/mL) and AG genotype (98.7 ± 72.3 ng/mL) (Kruskal-Wallis test, p = 0.25). Thus, CES1 rs8192935 is significantly associated with plasma concentrations of dabigatran in Kazakhstani NVAF patients (p < 0.05). The level of the plasma concentration shows that biotransformation of the dabigatran processed faster in individual carriers of GG genotype rs8192935 in the CES1 gene than with AA genotype.

Hormetic effects of EGC and EGCG on CES1 activity and its rescue from oxidative stress in rat liver S9.

Carboxylesterase 1 (CES1) is a hydrolytic enzyme that plays an important role in the activation or deactivation of many therapeutic agents, thus affecting their pharmacokinetic and pharmacodynamic outcomes. Using rat liver S9 as an enzyme source and enalapril as a CES1 substrate, the present study examined effects of a number of flavonoids on the formation of enalaprilat (the active form of enalapril) produced by CES1-mediated hydrolysis. While a majority of flavonoids tested showed inhibition on CES1, an unexpected hormetic effect was observed for epigallocatechin (EGC) and epigallocatechin gallate (EGCG), i.e., stimulatory effect at low concentrations and enzyme inhibition at high concentrations. Further experiments revealed that oxidative stress caused by hydrogen peroxide, arachidonic acid plus iron, and oxidized low density lipoproteins (oxLOL) reduced CES1 activity in rat liver S9 and the loss of CES1 enzyme activity could be rescued largely by EGC or EGCG. In contrast, such effects were minimal in human liver S9, probably due to the presence of a higher ratio of reduced vs oxidized forms of glutathione. The above findings suggest that the polyphenolic nature of EGC or EGCG might be responsible for rescuing CES1 activity under oxidative stress. Because of the importance of CES1 in drug activation or deactivation and rat liver S9 as a versatile in vitro system used for drug metabolism studies and drug safety assessment, caution should be exercised to avoid potential biases for data interpretation and decision making when CES1 activity in rat liver S9 is evaluated with dependency on experimental conditions.

Natural deletion of mouse carboxylesterases Ces1c/d/e impacts drug metabolism and metabolic syndrome development.

Mammalian carboxylesterase 1 enzymes can hydrolyze many xenobiotic chemicals and endogenous lipids. We here identified and characterized a mouse strain (FVB/NKI) in which three of the eight Ces1 genes were spontaneously deleted, removing Ces1c and Ces1e partly, and Ces1d entirely. We studied the impact of this Ces1c/d/e deficiency on drug and lipid metabolism and homeostasis. Ces1c/d/e-/- mice showed strongly impaired conversion of the anticancer prodrug irinotecan to its active metabolite SN-38 in plasma, spleen and lung. Plasma hydrolysis of the oral anticancer prodrug capecitabine to 5-DFCR was also profoundly reduced in Ces1c/d/e-/- mice. Our findings resolved previously unexplained FVB/NKI pharmacokinetic anomalies. On a medium-fat diet, Ces1c/d/e-/- female mice exhibited moderately higher body weight, mild inflammation in gonadal white adipose tissue (gWAT), and increased lipid load in brown adipose tissue (BAT). Ces1c/d/e-/- males showed more pronounced inflammation in gWAT and an increased lipid load in BAT. On a 5-week high-fat diet exposure, Ces1c/d/e deficiency predisposed to developing obesity, enlarged and fatty liver, glucose intolerance and insulin resistance, with severe inflammation in gWAT and increased lipid load in BAT. Hepatic proteomics analysis revealed that the acute phase response, involved in the dynamic cycle of immunometabolism, was activated in these Ces1c/d/e-/- mice. This may contribute to the obesity-related chronic inflammation and adverse metabolic disease in this strain. While Ces1c/d/e deficiency clearly exacerbated metabolic syndrome development, long-term (18-week) high-fat diet exposure overwhelmed many, albeit not all, observed phenotypic differences.

Loss of renal tubular G9a benefits acute kidney injury by lowering focal lipid accumulation via CES1.

Surgery-induced renal ischemia and reperfusion (I/R) injury and nephrotoxic drugs like cisplatin can cause acute kidney injury (AKI), for which there is no effective therapy. Lipid accumulation is evident following AKI in renal tubules although the mechanisms and pathological effects are unclear. Here, we report that Ehmt2-encoded histone methyltransferase G9a is upregulated in patients and mouse kidneys after AKI. Renal tubular specific knockout of G9a (Ehmt2Ksp ) or pharmacological inhibition of G9a alleviates lipid accumulation associated with AKI. Mechanistically, G9a suppresses transcription of the lipolytic enzyme Ces1; moreover, G9a and farnesoid X receptor (FXR) competitively bind to the same promoter regions of Ces1. Ces1 is consistently observed to be downregulated in the kidney of AKI patients. Pharmacological inhibition of Ces1 increases lipid accumulation, exacerbates renal I/R-injury and eliminates the beneficial effects on AKI observed in Ehmt2Ksp mice. Furthermore, lipid-lowering atorvastatin and an FXR agonist alleviate AKI by activating Ces1 and reducing renal lipid accumulation. Together, our results reveal a G9a/FXR-Ces1 axis that affects the AKI outcome via regulating renal lipid accumulation.

Generation of Caco-2 cells with predictable metabolism by CYP3A4, UGT1A1 and CES using the PITCh system.

Caco-2 cells are widely used as an in vitro intestinal model. However, the expression levels of the drug-metabolizing enzymes CYP3A4 and UGT1A1 are lower in these cells than in intestinal cells. Furthermore, the majority of prodrugs in use today are ester-containing, and carboxylesterase (CES) 1 and CES2 are among the enzymes that process the prodrugs into drugs. In the human small intestine, CES1 is hardly expressed while CES2 is highly expressed, but the CES expression pattern in Caco-2 cells is the opposite. In this study, we generated CYP3A4-POR-UGT1A1-CES2 knock-in (KI) and CES1 knock-out (KO) Caco-2 (genome-edited Caco-2) cells using a PITCh system. Genome-edited Caco-2 cells were shown to express functional CYP3A4, POR, UGT1A1 and CES2 while the expression of the CES1 protein was completely knocked out. We performed transport assays using temocapril. The Papp value of temocapril in genome-edited Caco-2 cells was higher than that in WT Caco-2 cells. Interestingly, the amount of temocaprilat on the apical side in genome-edited Caco-2 cells was lower than that in WT Caco-2 cells. These results suggest that genome-edited Caco-2 cells are more suitable than WT Caco-2 cells as a model for predicting intestinal drug absorption and metabolism.

MFGE8 links absorption of dietary fatty acids with catabolism of enterocyte lipid stores through HNF4γ-dependent transcription of CES enzymes.

Enterocytes modulate the extent of postprandial lipemia by storing dietary fats in cytoplasmic lipid droplets (cLDs). We have previously shown that the integrin ligand MFGE8 links absorption of dietary fats with activation of triglyceride (TG) hydrolases that catabolize cLDs for chylomicron production. Here, we identify CES1D as the key hydrolase downstream of the MFGE8-αvß5 integrin pathway that regulates catabolism of diet-derived cLDs. Mfge8 knockout (KO) enterocytes have reduced CES1D transcript and protein levels and reduced protein levels of the transcription factor HNF4γ. Both Ces1d and Hnf4γ KO mice have decreased enterocyte TG hydrolase activity coupled with retention of TG in cLDs. Mechanistically, MFGE8-dependent fatty acid uptake through CD36 stabilizes HNF4γ protein level; HNF4γ then increases Ces1d transcription. Our work identifies a regulatory network that regulates the severity of postprandial lipemia by linking dietary fat absorption with protein stabilization of a transcription factor that increases expression of hydrolases responsible for catabolizing diet-derived cLDs.

Carboxylesterase 1 family knockout alters drug disposition and lipid metabolism.

The mammalian carboxylesterase 1 (Ces1/CES1) family comprises several enzymes that hydrolyze many xenobiotic chemicals and endogenous lipids. To investigate the pharmacological and physiological roles of Ces1/CES1, we generated Ces1 cluster knockout (Ces1 -/- ) mice, and a hepatic human CES1 transgenic model in the Ces1 -/- background (TgCES1). Ces1 -/- mice displayed profoundly decreased conversion of the anticancer prodrug irinotecan to SN-38 in plasma and tissues. TgCES1 mice exhibited enhanced metabolism of irinotecan to SN-38 in liver and kidney. Ces1 and hCES1 activity increased irinotecan toxicity, likely by enhancing the formation of pharmacodynamically active SN-38. Ces1 -/- mice also showed markedly increased capecitabine plasma exposure, which was moderately decreased in TgCES1 mice. Ces1 -/- mice were overweight with increased adipose tissue, white adipose tissue inflammation (in males), a higher lipid load in brown adipose tissue, and impaired blood glucose tolerance (in males). These phenotypes were mostly reversed in TgCES1 mice. TgCES1 mice displayed increased triglyceride secretion from liver to plasma, together with higher triglyceride levels in the male liver. These results indicate that the carboxylesterase 1 family plays essential roles in drug and lipid metabolism and detoxification. Ces1 -/- and TgCES1 mice will provide excellent tools for further study of the in vivo functions of Ces1/CES1 enzymes.

The role of CYP1A1/2 in cholesterol ester accumulation provides a new perspective for the treatment of hypercholesterolemia.

Cholesterol is an important precursor of many endogenous molecules. Disruption of cholesterol homeostasis can cause many pathological changes, leading to liver and cardiovascular diseases. CYP1A is widely involved in cholesterol metabolic network, but its exact function has not been fully elucidated. Here, we aim to explore how CYP1A regulates cholesterol homeostasis. Our data showed that CYP1A1/2 knockout (KO) rats presented cholesterol deposition in blood and liver. The serum levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and total cholesterol were significantly increased in KO rats. Further studies found that the lipogenesis pathway (LXRα-SREBP1-SCD1) of KO rats was activated, and the key protein of cholesterol ester hydrolysis (CES1) was inhibited. Importantly, lansoprazole can significantly alleviate rat hepatic lipid deposition in hypercholesterolemia models by inducing CYP1A. Our findings reveal the role of CYP1A as a potential regulator of cholesterol homeostasis and provide a new perspective for the treatment of hypercholesterolemia.

The Influence of Structural Variants of the CES1 Gene on the Pharmacokinetics of Enalapril, Presumably Due to Linkage Disequilibrium with the Intronic rs2244613.

Variants in the CES1 gene encoding carboxylesterase 1 may affect the metabolism of enalapril to the active metabolite enalaprilat. It was shown that the A allele of rs71647871 and the C allele of rs2244613 led to a decrease in plasma enalaprilat concentrations. This study aimed to estimate the effect of structural haplotypes of CES1 containing the pseudogene CES1P1, or a hybrid of the gene and the pseudogene CES1A2, on the pharmacokinetics of enalapril. We included 286 Caucasian patients with arterial hypertension treated with enalapril. Genotyping was performed using real-time PCR and long-range PCR. Peak and trough plasma enalaprilat concentrations were lower in carriers of CES1A2. The studied haplotypes were in linkage disequilibrium with rs2244613: generally, the A allele was in the haplotype containing the CES1P1, and the C allele was in the haplotype with the CES1A2. Thus, carriers of CES1A2 have reduced CES1 activity against enalapril. Linkage disequilibrium of the haplotype containing the CES1P1 or CES1A2 with rs2244613 should be taken into account when genotyping the CES1 gene.

CES1 and SLC6A2 Genetic Variants As Predictors of Response To Methylphenidate in Autism Spectrum Disorders.

Purpose: Autistic spectrum disorders (ASD) children and adolescents usually present comorbidities, with 40-70% of them affected by attention deficit hyperactivity disorders (ADHD). The first option of pharmacological treatment for these patients is methylphenidate (MPH). ASD children present more side effects and poorer responses to MPH than ADHD children. The objective of our study is to identify genetic biomarkers of response to MPH in ASD children and adolescents to improve its efficacy and safety. Patients and Methods: A retrospective study with a total of 140 ASD children and adolescents on MPH treatment was included. Fifteen polymorphisms within genes coding for the MPH target NET1 (SLC6A2) and for its primary metabolic pathway (CES1) were genotyped. Multivariate analyses including response phenotypes (efficacy, side-effects, presence of somnolence, irritability, mood alterations, aggressivity, shutdown, other side-effects) were performed for every polymorphism and haplotype. Results: Single marker analyses considering gender, age, and dose as covariates showed association between CES1 variants and MPH-induced side effects (rs2244613-G (p=0.04), rs2302722-C (p=0.02), rs2307235-A (p=0.03), and rs8192950-T alleles (p=0.03)), and marginal association between the CES1 rs2302722-C allele and presence of somnolence (p=0.05) and the SLC6A2 rs36029-G allele and shutdown (p=0.05). A CES1 haplotype combination was associated with efficacy and side effects (p=0.02 and 0.03 respectively). SLC6A2 haplotype combination was associated with somnolence (p=0.05). Conclusion: CES1 genetic variants may influence the clinical outcome of MPH treatment in ASD comorbid with ADHD children and adolescents.

The impact of ABCB1 and CES1 polymorphisms on the safety of dabigatran in patients with non-valvular atrial fibrillation.

BACKGROUND: This study aimed to analyze associations between genetic variants and plasma concentrations along with clinical outcomes in dabigatran in patients with non-valvular atrial fibrillation (NVAF). METHODS: We conducted a prospective study and enrolled NVAF patients treated with dabigatran in the real world. A total of 86 patients treated with 110 mg DE twice daily were recruited for this study. Blood samples were obtained from each patient and used for genotyping and determination of plasma dabigatran concentration. All bleeding and thromboembolic complications were recorded during the 1.5 years of follow-up. RESULTS: Eighty-three patients provided samples at the trough plasma level of dabigatran, and 58 patients provided samples at the peak plasma level of dabigatran. There was a significant association between the CES1 SNP rs8192935 and trough plasma concentrations of dabigatran (P = 0.013). Our results showed that the CES1 SNP rs8192935 significantly influenced dabigatran trough concentrations in the Chinese population, and carriers of the G allele had increased trough plasma concentrations of dabigatran compared to noncarriers. The ABCB1 SNP c.2482-2236G > A (rs4148738) was associated with major bleeding events in the addictive model (P = 0.046, OR = 3.29) and dominant model (P = 0.040, OR = 8.17). Additionally, the ABCB1 SNP c.3435 C > T (rs1045642) was associated with the incidence of major bleeding events in the addictive model (P = 0.043, OR = 3.34) and dominant model (P = 0.046, OR = 7.77). However, no significant associations were found between all the SNPs and the incidence of minor bleeding events. CONCLUSION: Our results indicated that the CES1 polymorphism rs8192935 was associated with trough plasma concentrations of dabigatran. Carriers of the G allele had increased trough plasma concentrations of dabigatran compared to noncarriers. The ABCB1 polymorphisms rs4148738 and rs1045642 were associated with an increased risk for major bleeding events for the first time in a Chinese population.

The Pharmacogenetic Impact on the Pharmacokinetics of ADHD Medications.

ADHD is a common condition in both children and adults. The most prescribed medications for the treatment of ADHD include methylphenidate, mixed amphetamine salts, atomoxetine, guanfacine, and clonidine. While each of these medications have their own distinct pharmacokinetic profile, the extent to which pharmacogenetics effects their pharmacokinetic parameters is best described in atomoxetine, followed by methylphenidate. Atomoxetine is predominantly metabolized by cytochrome p450 2D6 (CYP2D6), while methylphenidate is metabolized by carboxylesterase 1 (CES1). Both CYP2D6 and CES1 have multiple variants resulting in varying levels of enzyme activity; however, to date, the functional consequence of variants and alleles for CYP2D6 is better characterized as compared to CES1. Regarding CYP2D6, individuals who are poor metabolizers prescribed atomoxetine experience up to ten-fold higher exposure as compared to normal metabolizers at comparable dosing. Additionally, individuals prescribed methylphenidate with the rs71647871 variant may experience up to 2.5-fold higher exposure as compared to those without. Having this pharmacogenetic information available may aid clinicians and patients when choosing medications and doses to treat ADHD.

Integrative systems analysis identifies genetic and dietary modulators of bile acid homeostasis.

Bile acids (BAs) are complex and incompletely understood enterohepatic-derived hormones that control whole-body metabolism. Here, we profiled postprandial BAs in the liver, feces, and plasma of 360 chow- or high-fat-diet-fed BXD male mice and demonstrated that both genetics and diet strongly influence BA abundance, composition, and correlation with metabolic traits. Through an integrated systems approach, we mapped hundreds of quantitative trait loci that modulate BAs and identified both known and unknown regulators of BA homeostasis. In particular, we discovered carboxylesterase 1c (Ces1c) as a genetic determinant of plasma tauroursodeoxycholic acid (TUDCA), a BA species with established disease-preventing actions. The association between Ces1c and plasma TUDCA was validated using data from independent mouse cohorts and a Ces1c knockout mouse model. Collectively, our data are a unique resource to dissect the physiological importance of BAs as determinants of metabolic traits, as underscored by the identification of CES1C as a master regulator of plasma TUDCA levels.