Genetic Polymorphisms Of Enzymes Research Articles

Associations between (pharmaco-)genetic markers and postoperative pain after inguinal hernia repair – a prospective study protocol

BackgroundPostoperative pain is a common complication following surgery, with severity and duration varying between patients. Chronic postoperative pain after inguinal hernia surgery has an incidence rate of approximately 10%. Risk factors for acute and chronic pain following hernia surgery include age, sex, psychosocial factors, and demographic background. Additionally, genetic polymorphisms in enzymes involved in pain mechanisms, as well as the metabolism of analgesics might influence pain perception, pain development, and response to pain medications. Key enzymes include the catechol-o-methyltransferase (COMT), the µ-opioid receptor 1 (OPRM1), and the cytochrome P450 2D6 (CYP2D6).CYP2D6 plays a crucial role in metabolizing analgesics such as tramadol, codeine, and oxycodone. It is also suspected to be involved in the synthesis of catecholamines and endogenous morphines suggesting a potential role in pathophysiology of pain. We hypothesize that the CYP2D6 activity influences the development of postoperative pain after hernia surgery.MethodsThis study is a prospective, observational, multicenter association study investigating adult patients scheduled for inguinal hernia surgery using a robotic-assisted (rTAPP) approach. Patients are enrolled during the preoperative surgical consultation. A buccal swab is collected for genetic testing at this time. Pain at the site of the hernia is assessed using the validated EuraHSQoL score preoperatively and at 2, 4, and 6 weeks postoperatively. Additionally, information on co-medication and details of the surgery will be collected. The planned number of participants is 350 patients. The primary objective is to analyze the association between different genotype-predicted CYP2D6 phenotypes and patient-reported pain intensity 6 weeks after surgery. Secondary objectives include the association between further genetic variants, such as the COMT rs4680 and OPRM1 rs1799971 genotype, and pain severity. Additionally, the potential of pharmacogenetic panel testing to optimize analgesic therapy in hernia surgery patients will be explored.DiscussionThe findings of this study are expected to provide valuable insights into identifying patients at higher risk for postoperative pain before surgery. This knowledge could pave the way for tailored interventions during and after surgery for these specific patients.Trial registrationDeutsches Register Klinischer Studien https://www.drks.de/DRKS00034796 Registered on August 07, 2024.

Pharmacogenetic testing: current state of the issue

Aim. The purpose of this work is to emphasize the importance and practical benefits of pharmacogenetics in medicine, demonstrating how the integration of pharmacogenetics into clinical practice can improve treatment outcomes and enhance the safety of therapies. Pharmacogenetics is a rapidly developing branch of pharmacology that studies how genetic variation affects an individual’s response to drugs. By understanding these genetic differences, healthcare providers can tailor drug therapy to maximize efficacy and minimize adverse drug reactions. The field aims to move away from the traditional one-size-fits-all approach and instead personalize medical treatment based on a person’s genetic makeup. The ability to predict a person’s response to medication based on their genetic profile has profound implications. For example, pharmacogenetic testing can identify patients at risk for life-threatening adverse drug reactions, such as drug-induced liver injury. This proactive approach can prevent adverse events, improving patient safety and the overall quality of care. In addition, pharmacogenetics aids in the development of new drugs by identifying genetic markers associated with drug responses, optimizing the drug development process, and reducing the time and costs associated with bringing new drugs to market. Key advances in pharmacogenetics include the identification of genetic polymorphisms in enzymes, such as cytochrome P450, that affect drug metabolism, thereby influencing both safety and efficacy. Pharmacogenetic testing allows doctors to predict the best drug and dosage for a patient, improving treatment outcomes and reducing the risk of adverse drug events. Despite its potential, the integration of pharmacogenetics into clinical practice faces challenges, including a lack of reliable clinical evidence, inadequate physician education, and the need for a comprehensive health IT infrastructure to support the use of genetic data. Ethical and legal issues, such as patient privacy and the risk of genetic discrimination, also present significant obstacles. However, continued research, the development of genetic testing technologies, and interdisciplinary collaborations are paving the way for more widespread adoption of pharmacogenetics, which promises to significantly improve patient care and healthcare efficiency. Key resources such as PharmGKB, CPIC, and the NIH provide valuable information and guidance for clinicians, researchers, and students, helping bridge the gap between genetics research and clinical application. Conclusions. Pharmacogenetics represents a significant advancement in personalized medicine, offering the potential to tailor drug therapies to individual genetic profiles. Although the field has made substantial progress, challenges remain in the form of insufficient clinical evidence, implementation barriers, and ethical concerns. Continued research and collaboration among stakeholders are essential to fully realize the benefits of pharmacogenetic testing in clinical practice.

Angiotensin-Converting Enzyme Genetic Polymorphism rs4343 as Risk of Diabetic Nephropathy in Jambi-Malay Population

Background: Diabetic nephropathy (DN) is one of the frequent complications of type II diabetes mellitus (T2DM) in Jambi province. Controlling blood glucose and blood pressure does not guarantee DN prevention, since genetic factors may also contribute to this disease. Multi-ethnic studies showed that one of the strongest genetic factors associated with DN was single nucleotide polymorphism rs4343 of angiotensin-converting enzyme (ACE) gene. Study regarding phenotype-genotype association of ACE rs4343 and DN has not yet been performed in Jambi Province, which is dominated by Malay ethnicity. This study was conducted to reveal the association between ACE rs4343 and the risk of DN in the Jambi-Malay population.Materials and methods: This was a cross-sectional study involving 75 subjects (44 with DN and 31 without DN) who suffered from T2DM and hypertension. DN was defined as albumin to creatinine ratio (ACR) ≥30 mg/g. Genotyping was performed with one-step tetra amplification refractory mutation system-polymerase chain reaction (PCR) using specific primer for ACE rs4343. Bivariate and multivariate analyses were performed to analyze the genetic risk for DN.Results: The bivariate analysis showed the proportion of DN subjects was higher than non-DN within the AG genotype (11:1) than within the AA (33:30) genotype. This difference was statistically significant (p=0.012; OR (95% CI): 10.00 (1.22-82.15)). Multivariate analysis showed that AG genotype (p=0.047; OR (95% CI): 10.04 (1.03-97.31)) and uncontrolled blood pressure (p=0.001; OR (95% CI): 6.72 (2.08-21.71)) were the risk factors of DN in the Jambi-Malay population.Conclusion: Polymorphism of ACE rs4343 is a risk factor of DN in the Jambi-Malay Population.Keywords: rs4343, angiotensin-converting enzyme gene, diabetic nephropathy, Malay, Jambi

No Association of AS3MT Gene Polymorphisms with Susceptibility to Hepatotoxicity and in APL Patients Treated with AS2O3: A Single Center Study

Background: Arsenic three oxide (As2O3) is the treatment choice for acute promyelocytic leukemia (APL). Little is known about possible risk factors with predictive value for toxicity caused by As2O3. Biomethylation is considered to be a major pathway of detoxification for inorganic arsenics (iAs). Arsenic Methyltransferase (AS3MT) is one of the key enzymes involved in the transfer of a methyl group from S-adenosyl-L-methionine to trivalent arsenical and plays a critical role in arsenic detoxification. Polymorphisms in hAS3MT lead to a change in the catalytic activity of the enzyme and may increase the risk of arsenic-related toxicity. In this study, we investigated the association of the AS3MT polymorphisms (rs11191439, rs3740390, and rs3740393) genes with hepatotoxicity in APL patients treated with As2O3.
 Materials and Methods: Genotyping was performed in 140 adult patients with APL treated with As2O3 using PCR-RFLP for rs11191439 and tetra-primer ARMS-PCR for rs3740390 and rs3740393. The results of PCR-RFLP and ARMS-PCR were confirmed by direct sequencing of 10 % of DNA samples. The results were analyzed using SNPStats, SPSS, and FinchTV. Hepatotoxicity was graded according to the National Cancer Institute's Common Toxicity Criteria (CTC).
 Results: Hepatotoxicity was seen in 52 of the 140 patients (37.1%), with grades I and II hepatotoxicity in 40 (28.6%) and grades III and IV hepatotoxicity in 12 (8.5%) patients. The association between the three polymorphisms and hepatotoxicity was evaluated using five genetic models and none of the three studied polymorphisms were significantly associated with hepatotoxicity.
 Discussion: The results of our study showed that AS3MT rs11191439, rs3740390, and rs3740393 polymorphisms are not associated with hepatotoxicity in APL patients. Genetic polymorphisms in enzymes which are involved in arsenic metabolism have been shown to have ethnicity and race-related differences. To more precisely characterize the association between AS3MT gene polymorphism and hepatotoxicity, future large-scale studies in non-Asian populations and other ethnicities are needed.

Organochlorine pesticide exposures, metabolic enzyme genetic polymorphisms and semen quality parameters among men attending an infertility clinic.

The associations of organochlorine pesticides (OCPs) with semen quality from human studies are conflicting, and also it is largely unknown whether the associations are modified by genetic polymorphisms. We aimed to evaluate the associations between serum concentrations of 18 OCPs and semen quality among 387 Chinese men, and further to examine the modifying effects by genetic polymorphisms in cytochrome P450 (CYP2E1) and glutathione S-transferase (GSTT1). Multivariable linear regressions were used to evaluate the relationships between serum OCP concentrations and semen quality, and the role of CYP2E1 and GSTT1 polymorphisms in modifying the associations were assessed. Multiple testing was adjusted using the false discovery rate (FDR). We observed that men with detectable concentrations of serum ɤ-HCH had a decrease in sperm motility of 7.07% (95% CI: -10.9%, -3.24%) compared to those with undetectable concentrations (FDR-P value=0.02). Men with TT of CYP2E1 rs 915906 genotypes had higher median concentrations of serum dieldrin compared with those with CT/CC of CYP2E1 rs 915906 genotypes. There were interactions between CYP2E1 and GSTT1 polymorphisms and certain OCPs namely ɤ-HCH, δ-HCH, dieldrin, endosulfan I, and endrin aldehyde on semen quality. For example, elevated dieldrin levels in relation to decreased sperm concentration, sperm count, and sperm motility were only observed among men with CC of CYP2E1 rs2031920 genotypes (all Pinteraction < 0.05). However, these interactions were not statistically significant after the FDR adjustment. Our results suggested that CYP2E1 and GSTT1 polymorphisms may modify the effects of OCP exposures on semen quality. Due to the relatively small size samples, further investigation is warranted to confirm the findings.

Organochlorine Pesticide Exposures, Metabolic Enzyme Genetic Polymorphisms and Semen Quality Parameters Among Men Attending an Infertility Clinic

Organochlorine Pesticide Exposures, Metabolic Enzyme Genetic Polymorphisms and Semen Quality Parameters Among Men Attending an Infertility Clinic

Acetaldehyde exposure underlies functional defects in monocytes induced by excessive alcohol consumption

Increased intestinal permeability and hepatic macrophage activation by endotoxins are involved in alcohol-induced liver injury pathogenesis. Long-term alcohol exposure conversely induces endotoxin immune tolerance; however, the precise mechanism and reversibility are unclear. Seventy-two alcohol-dependent patients with alcohol dehydrogenase-1B (ADH1B, rs1229984) and aldehyde dehydrogenase-2 (ALDH2, rs671) gene polymorphisms admitted for alcohol abstinence were enrolled. Blood and fecal samples were collected on admission and 4 weeks after alcohol cessation and were sequentially analyzed. Wild-type and ALDH2*2 transgenic mice were used to examine the effect of acetaldehyde exposure on liver immune responses. The productivity of inflammatory cytokines of peripheral CD14+ monocytes in response to LPS stimulation was significantly suppressed in alcohol dependent patients on admission relative to that in healthy controls, which was partially restored by alcohol abstinence with little impact on the gut microbiota composition. Notably, immune suppression was associated with ALDH2/ADH1B gene polymorphisms, and patients with a combination of ALDH2*1/*2 and ADH1B*2 genotypes, the most acetaldehyde-exposed group, demonstrated a deeply suppressed phenotype, suggesting a direct role of acetaldehyde. In vitro LPS and malondialdehyde-acetaldehyde adducted protein stimulation induced direct cytotoxicity on monocytes derived from healthy controls, and a second LPS stimulation suppressed the inflammatory cytokines production. Consistently, hepatic macrophages of ethanol-administered ALDH2*2 transgenic mice exhibited suppressed inflammatory cytokines production in response to LPS compared to that in wild-type mice, reinforcing the contribution of acetaldehyde to liver macrophage function. These results collectively provide new perspectives on the systemic influence of excessive alcohol consumption based on alcohol-metabolizing enzyme genetic polymorphisms.

Genetic Polymorphisms in Enzymes Involved in One-Carbon Metabolism and Anti-epileptic Drug Monotherapy on Homocysteine Metabolism in Patients With Epilepsy.

Aims: To investigate the effects of single nucleotide polymorphisms (SNPs) in genes of one-carbon metabolism (OCM) related enzymes and anti-epileptic drug (AED) monotherapy on homocysteine (Hcy) metabolism in patients with epilepsy, and to further explore specific SNPs that may increase patients' susceptibility to the effects of AEDs on the Hcy imbalance.Method: This case-control study analyzed 279 patients with epilepsy, including patients receiving monotherapy with valproate (VPA) (n = 53), oxcarbazepine (OXC) (n = 71), lamotrigine (LTG) (n = 55), or levetiracetam (LEV) (n = 35) and patients who had not taken any AEDs (controls, n = 65) for at least 6 months. Serum levels of vitamin B12 (vit B12), folate (FA) and Hcy were measured, and 23 SNPs in 13 genes of OCM-related enzymes were genotyped in all patients.Results: Methylenetetrahydrofolate reductase (MTHFR) rs1801133 was associated with elevated serum Hcy levels in patients with epilepsy (P < 0.001), and patients presenting the TT genotype exhibited higher serum Hcy levels than patients with the CC (P < 0.001) or CT (P < 0.001) genotype. A subsequent multiple linear regression analysis showed that AED monotherapy with VPA (vs. control: P = 0.023) or OXC (vs. control: P = 0.041), and genotypes of MTHFR rs1801133 TT (vs. CC: P < 0.001; vs. CT: P < 0.001), transcobalamin 2 (TCN2) rs1801198 CC (vs. GC: P = 0.039) and folate receptor 1 (FOLR1) rs2071010 AA (vs. GA: P = 0.031) were independent risk factors for higher Hcy levels. In the subgroup analysis of patients taking OXC, we found that patients with genotypes of MTHFR rs1801133 TT (vs. CC: P = 0.001; vs. CT: P < 0.001) and TCN2 rs1801198 CC (vs. GC: P = 0.021; vs. GG: P = 0.018) exhibited higher serum Hcy levels.Conclusions: VPA, OXC, and genotypes of MTHFR rs1801133 TT, TCN2 rs1801198 CC, and FOLR1 rs2071010 AA are all independent risk factors for elevated Hcy levels in patients with epilepsy. Moreover, genotypes of MTHFR rs1801133 TT and TCN2 rs1801198 CC may increase patients' susceptibility to the effect of OXC on disrupting Hcy homeostasis.

The association between cytochrome P450 polymorphisms and anti-tuberculosis drug-induced liver injury: a systematic review and meta-analysis.

Isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA), and ethambutol (EMB) are the four most common drugs for the first-line treatment of tuberculosis (TB). Although chemotherapy drugs are widely used in the treatment of TB, and achieved good results, but the side effects, especially anti-tuberculosis drug-induced liver injury (ATDILI), cannot be overlooked. Many researchers have made efforts to uncover the association of cytochrome P450 (CYP) enzyme genetic polymorphisms with ATDILI. In this study, we systematically reviewed and meta-analyzed the relationship between CYP polymorphism and susceptibility to ATDILI. We carried out literature searches of PubMed, Ovid, the Cochrane Library, Web of Science and Chinese National Knowledge Infrastructure (CNKI). Medical Subject Headings (MeSH) terms including "cytochrome P450 enzyme", "drug-induced liver injury", "polymorphism", "tuberculosis", and "hepatotoxicity" were used as keywords for our searches. The pooled odds ratio (OR) of all studies for CYP2E1 to the risk of ATDILI was 1.18 [95% confidence interval (CI): 0.82-1.71]. The articles in this meta-analysis were observed to be mildly heterogeneous. Further subgroup analysis revealed that the patients who receiving a four-drug protocol (INH + RIF + PZA + EMB) or three-drug protocol (INH + RIF + PZA) regimens showed a higher risk of ATDILI than those who receiving INH alone. However, subgroup analyses according to participants' ethnic origin, study type, and the definition of ATDILI produced no statistically significant results. Associations between other genes in the CYP family and ATDILI were indistinct and equivocal. Our meta-analysis has uncovered an association between CYP2E1 RsaI/PstI polymorphisms and ATDILI, especially among patients who receive a four-drug (INH + RIF + PZA + EMB) or three-drug (INH + RIF + PZA) anti-TB treatment regimen.

Comprehensive analysis of important pharmacogenes in Koreans using the DMET™ platform.

Genetic polymorphisms of enzymes and transporters associated with the absorption, distribution, metabolism, and elimination (ADME) of drugs are one of the major factors that contribute to interindividual variations in drug response. In the present study, we aimed to elucidate the pharmacogenetic profiles of the Korean population using the Affymetrix Drug Metabolizing Enzyme and Transporters (DMET™) platform. A total of 1,012 whole blood samples collected from Korean subjects were genotyped using the DMET™ plus microarray. In total, 1,785 single nucleotide polymorphism (SNP) markers for 231 ADME genes were identified. The genotype and phenotype of 13 clinically important ADME genes implemented in the Clinical Pharmacogenetics Implementation Consortium guidelines were compared among different ethnic groups. Overall, the genotype frequencies of the Korean population were similar to those of the East Asian population. Several genes, notably CYP2C19 and VKORC1, showed marked differences in Koreans compared to Europeans (EURs) or Africans (AFRs). The percentage of CYP2C19 poor metabolizers was 15% in Koreans and less than 3% in EURs or AFRs. The frequencies of causative SNPs of the VKORC1 gene for the low warfarin dose phenotype were 90%, 60%, and 10% in Koreans, EURs and AFRs, respectively. Our findings can be utilized for optimal pharmacotherapy in Korean patients.

Experience of Chita the program of the Scientific Society of Gastroenterologists of Russia and Russian Scientific Medical Society of Internal Medicine “Physicians without helicobacteriosis”

Objective.To determine the prevalence ofHelicobacter pylori(HP) in doctors in Chita, to identify clinical manifestations of infection, endoscopic, ultrasound and morphological changes in the stomach, to conduct eradication treatment with an assessment of its effectiveness, to determine the resistance of HP to clarithromycin and to develop treatment tactics for HP-associated diseases in the region.Material and methods.70 doctors of Chita were examined, including 55 women and 15 men, average age 47.04±12.76 years (20 persons were 39 years and younger, 33 persons were 40–59 years, 17 people were 60 years and older; 27 persons were gastroenterologists, 17 — therapists, 11 — pediatricians, 5 — surgeons and 10 persons were doctors of other specialties). All doctors underwent antigen (AH) of HP determination in feces, a survey on the original questionnaire to assess clinical manifestations. Ultrasound examination of the stomach was performed in 47 doctors. Endoscopy of the upper gastrointestinal tract (GI) was performed in 35 persons. During endoscopy, in 29 doctors biopsy material of the mucous membrane from 5 points of the stomach were taken. A histological examination of biopsy samples was performed with an assessment using the OLGA system. The resistance of HP to clarithromycin was determined by the molecular genetic method in biopsy samples of gastric biopsy. 44 doctors conducted eradication with different schemes. Adverse events (AE) and treatment tolerance were evaluated. Control of eradication was carried out 6–8 weeks after the end of therapy by determining AH of HP in the feces. Statistical processing was carried out using the method of descriptive statistics, criterion of Student and criterion x2(Biostatprogramm).Results.A positive AH of HP in feces was registered in 71.4% of the doctors examined: 73.3% of men and 70.9% of women, 75% of people under the age of 39 years, 72.7% of those aged 40–59 years and 64.7% are over 60 years old. Gastroenterologists were infected in 63%, therapists in 70.6%, pediatricians in 72.7%, surgeons in 80%, another specialists in 90% of cases. In the presence of HP, 81.6% of the examined showed symptoms from the digestive organs, 3 times more often a hereditary history of stomach cancer was determined. The wall thickness of the stomach during ultrasound in the infected was recorded 0.21–0.18 mm more than in the group of HP-negative individuals. A histological examination of III–IV degree of activity of inflammation in the stomach was diagnosed in 86.1%, stage III atrophy and colonic metaplasia in 20.7% of the examined doctors. The desire to conduct eradication treatment was expressed by 78% of doctors, 44 people completed the therapy. Non-compliance with the eradication regimen was noted in 9 people. AE were registered in 76.6% of cases. The efficacy of all regimens was 71.4%: when using the regimen with clarithromycin — 73%, with josamycin — 100%, with tetracycline and metronidazole — 33%, with levofloxacin — 100%. HP DNA was detected in 27 samples of gastric. In 10 cases, mutations A2142G and A2143G in the HP genome were detected, providing resistance to clarithromycin, which amounted to 37%.Conclusion1. 71.4% of doctors in Chita are infected with HP, among which the bacterium is most often detected at a young age (39 years and younger).2. Infected doctors are more likely to have gastrointestinal symptoms, a history of gastric damage, and hereditary gastric cancer.3. In 20.7% of doctors, histological examination revealed colonic metaplasia and dysplasia, which confirms the need for treatment and requires further observation.4. Only 78% of Chita doctors expressed their readiness to eradicate HP, and 20.4% of those who started treatment did not comply with the treatment regimen. This fact requires further educational activities.5. The efficacy of eradication by all schemes was 71.4%. Genotypic resistance of HP to clarithromycin was found in 37% of doctors. Further studies are needed to identify the characteristics of the macro- and microorganism (genetic polymorphism of enzymes, HP mutations) in groups, both among doctors and other categories of patients who do not have professional contacts with microorganisms and antibiotics in order to develop recommendations on the use of HP eradication schemes in region.

Association of Drug Metabolic Enzyme Genetic Polymorphisms and Adverse Drug Reactions in Patients Receiving Rifapentine and Isoniazid Therapy for Latent Tuberculosis.

Weekly rifapentine and isoniazid therapy (3HP) is the most frequent treatment for latent tuberculosis infection (LTBI). However, the association between major adverse drug reactions (ADRs) and drug metabolic enzyme single-nucleotide polymorphisms (SNPs) remains unclear. In this study, 377 participants who received the 3HP regimen were recruited and examined for genotyping of CYP5A6, CYP2B6, CYP2C19, CYP2E1, and NAT2 SNPs. In our study, 184 participants (48.4%) developed ADRs. Moreover, CYP2C19 rs4986893 (TT vs. CC+CT, odds ratio [OR] [95% CI]: 2.231 [1.015–4.906]), CYP2E1 rs2070676 (CC vs. CG+GG, OR [95% CI]: 1.563 [1.022–2.389]), and CYP2E1 rs2515641 (CC vs. CT+TT, OR [95% CI]: 1.903 [1.250–2.898]) were associated with ADR development. In conclusion, CYP2C19 and CYP2E1 SNPs may provide useful information regarding ADRs in LTBI patients receiving the 3HP regimen.

PB1658 RELEVANCE OF TPMT, NUDT15 AND ABCC4 GENOTYPING IN PEDIATRIC ACUTE LYMPHOBLASTIC LEUKEMIA/LYMPHOMA

Background:Acute lymphoblastic leukemia/lymphoma (ALL/lymphoma) is the most common pediatric cancer. The approved standard treatment includes a 24‐month maintenance phase with 6‐mercaptopurine (6‐MP) and methotrexate, achieving complete responses in 80% of the cases.According to the literature, there are genetic polymorphisms in enzymes involved in the thiopurine drugs metabolism (namely, thiopurine methyltransferase or TPMT and nudix hydrolase 15 or NUDT15) and transport (ATP binding cassette subfamily C member or ABCC4) that can influence their therapeutic effect and cause adverse events along this phase (myelosuppression, hepatotoxicity, pancreatitis, among others).Inherited TPMT deficiency (mainly, variants 2, 3A, 3B and 3C) is the primary genetic cause of thiopurine intolerance in Europeans and Africans, whereas risk alleles in NUDT15 explain most of thiopurine‐related myelosuppression in Asians and Hispanics. Not so well established are the presence of genetic variants in genes coding for drug transport proteins like ABCC4.The Clinical Pharmacogenetics Implementation Consortium has published recommendations for adjusting starting doses based on TPMT/NUDT15 genotypes but, although relevant to prevent severe adverse effects, these studies are not yet universally implemented.Aims:Genotyping pediatric ALL/lymphoma with hematologic toxicity along the maintenance phase of the oncologic treatment.Methods:Patients diagnosed with ALL/lymphoma since 2012, presenting hematologic toxicity to 6‐MP and requiring regular dose adjustments along the maintenance phase were studied for TPMT genotype. In case of negative study for TPMT, NUDT15 and ABCC4 genotypes were also explored.Results:Eleven patients were identified, median age 8 [1‐14] years, male gender in 6 cases (54.5%). Seven patients had a B‐ALL (63.6%), one had a T‐ALL and three had a lymphoma.Six patients already finished their maintenance phase. These had a median of 19.5 [7‐35] adjustments for 6‐MP dose along this phase for hematologic toxicity, with a median time of 14 days between adjustments. One of these patients was identified with the genotype TPMT 3A∗ (the most common variant allele in the Caucasian population that confers low enzyme activity), and required 23 adjustments for hematologic toxicity in a median time of 14 days [3‐116] until reaching the adequate dose.Five patients are still in the maintenance phase (median time of 9 [2‐11] months) and had already a median of 10 [2‐20] adjustments for hematologic toxicity, in a median time of 14 days between adjustments. From these, there are 3 cases identified with an ABCC4 genotype that seem to predispose to adverse hematologic events, requiring closer medical monitoring.All these 11 patients are alive and have no oncologic disease. Overall survival is 2 [1‐7] years and progression free survival is also 2 [1‐4] years.Summary/Conclusion:This study led to the implementation of TPMT genotyping in all Pediatric ALL/lymphoma patients in our center, before the maintenance phase and to a 50% dose reduction of 6‐MP in those with TPMT forms with low activity (TPMT∗2, TPMT∗3B, TPMT∗3C and TPMT∗3A) to reduce hematologic toxicity related to an excessive dose administered. Based on the results obtained for ABCC4 and NUDT15 genotypes and according to the literature, it is still not recommended the study of these additional genes for all patients.

Determining Risk Factors for Triple Whammy AKI using Computational Models of Long‐ Term Blood Pressure Regulation

Concurrent use of diuretics, angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB), and nonsteroidal anti‐inflammatory drugs (NSAIDs) increases the risk of acute kidney injury (AKI). AKI resulting from use of all three drugs is referred to as “triple whammy”. Diuretics and ACEI/ARB are often prescribed in tandem for the treatment of hypertension while some NSAIDs, such as ibuprofen, are available over the counter. As such, concurrent treatment with all three drugs is common.To address the critical need to better understand the mechanisms behind the increased risk of AKI and to identify potential risk factors, we use computational models of long‐term blood pressure regulation we developed previously. We hypothesize that individual variations in tubuloglomerular feedback, renal sympathetic nervous activity, and vasoactive hormones such as angiotensin II will determine whether or not triple whammy patients develop AKI. Other circumstances that we hypothesize to influence AKI development include hypertension, salt ingestion and sensitivity, and genetic polymorphisms in enzymes (ACE) or receptors (angiotensin type 1).The computational models used include variables describing the heart and circulation, kidney function, sodium and water reabsorption in the nephron, and the renin angiotensin system (RAS) and is fit separately for male and female humans.Support or Funding InformationThis research was supported by the Canada 150 Research Chair program and by the National Institutes of Health: National Institute of Diabetes and Digestive and Kidney Diseases, grant R01DK106102.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Optimal predictor for 6-mercaptopurine intolerance in Chinese children with acute lymphoblastic leukemia: NUDT15, TPMT, or ITPA genetic variants?

Background6-mercaptopurine (6-MP) contributes substantially to remarkable improvement in the survival of childhood acute lymphoblastic leukemia (ALL) patients. However, 6-MP also has dose-limiting toxicities, particularly life-threatening myelosuppression, due to genetic polymorphisms in enzymes that metabolize 6-MP. Promising biomarkers for predicting 6-MP-induced leukopenia is still unclear in Chinese population. Here, we evaluated the associations of NUDT15, TPMT and ITPA genotypes with 6-MP intolerance in our cohort of childhood ALL patients.MethodsA total of 105 Chinese pediatric patients with a confirmed diagnosis of ALL were enrolled. We identified the NUDT15 coding variant rs116855232 (c.415C > T), a newly discovered 6-MP toxicity-related locus in Asians, and polymorphisms in TPMT rs1142345 and ITPA rs11273540. Associations between genotypes and 6-MP dose sensitivity, leukopenia, hepatotoxicity, and therapy interruption were evaluated.ResultsThe minor allele frequencies (MAFs) of NUDT15 rs116855232, TPMT rs1142345 and ITPA rs11273540 were 15.7, 2.9, and 18.1%, respectively. NUDT15 and TPMT genetic variants were strongly associated with 6-MP dose intensity. Patients with NUDT15 homogenous genotype (TT) were highly sensitive to 6-MP (dose intensity of 60.27%) compared to these with heterozygous genotype (TC) or wild type (CC), who tolerated an average dose intensity of 83.83 and 94.24%, respectively. The NUDT15 variant was a predictor for leukopenia (OR: 3.62, 95% CI 1.377–9.501, P = 0.009) and early-onset leukopenia (OR: 9.63, 95% CI 2.764–33.514, P = 3.75 × 10− 4). No differences were found between 6-MP dose intensity and ITPA polymorphisms.ConclusionNUDT15 variant is an optimal predictor for 6-MP intolerance in Chinese pediatric ALL patients and may have greatly clinical implications for individualized therapy.

Role of glutathione‐S‐transferases in the metabolism of the anti‐cancer agent and aromatase inhibitor, exemestane

Breast cancer is the most commonly diagnosed cancer in women, with approximately 1 in 8 women in the U.S. developing breast cancer over their lifetime. The majority of breast cancers diagnosed each year are estrogen receptor positive (ER+). Drugs targeting the ER pathway are a major treatment modality for ER+ patients and are additionally prescribed for the prevention of breast cancer. Exemestane (EXE) is an inhibitor which blocks the enzyme aromatase in the final step of estrogen biosynthesis. Studies examining the long‐term use of EXE as a chemopreventative agent demonstrated a reduction in breast cancer incidence by more than 65%. However, response and toxicity varied widely among individuals, which may be attributed to genetic polymorphisms in enzymes that metabolize EXE. Data from our lab demonstrate that a cysteine conjugates of EXE and its active metabolite 17β‐dihydro‐EXE (17β‐DHE) make up 77% of the total metabolite in urine. Cysteine conjugates are formed from metabolism of glutathione (GSH) conjugates in a reaction catalyzed by the glutathione‐S‐transferases (GST) family of the enzymes. The goal of the present study was to identify hepatic GSTs active in the metabolism of EXE and 17β‐DHE and to determine kinetic parameters for the identified enzymes. In a screening of the Protein Atlas, a total of 12 cytosolic and 3 microsomal GSTs were found to be hepatically expressed. EXE‐GSH conjugation activity in human liver samples was screened by incubating GSH with EXE or 17β‐DHE (0.125–1.0 mM) in cytosol (HLC) or microsomes (HLM) prepared from human livers. GSH conjugates were formed for both cellular fractions, indicating that both cytosolic and microsomal GST enzymes are active against EXE and 17β‐DHE. GSH conjugates were detected by UPLC‐MS and quantified using synthesized EXE‐GS and 17β‐DHE‐GS standards. The purity and identity of both standards and internal standards were confirmed using NMR and UPLC‐MS and found to be &gt; 95% pure. Individual recombinant human GSTs were then screened to determine which enzyme is primarily responsible for the metabolism of EXE. Commercially available cytosolic GSTs were purchased, and their activity was verified with a common GST substrate, 1‐chloro‐2.4‐dinitrobenzene. Results from the individual EXE‐GSH conjugation assays indicate the cytosolic enzymes GSTA1, GSTM3 and GSTP1 are active against EXE and 17β‐DHE; studies of microsomal GSTs are on‐going. These data suggest that several GSTs, both cytosolic and microsomal, may be important in the phase II conjugation of EXE and its major active metabolite, 17β‐DHE.Support or Funding InformationThis study is supported by National Institutes of Health (NIH) (Grant R01‐ES025460 and R01‐CA164366) and the Health Sciences and Services Authority of SpokaneThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of Alcohol Consumption on Cardiovascular Health.

This review aims to discuss the effect of alcohol consumption on various cardiovascular (CV) diseases and CV mortality. Alcohol intake has consistently shown a J- or U-shaped relationship with several cardiovascular diseases. Light to moderate alcohol intake has been associated with lower risk of coronary artery disease, heart failure (HF), as well as CV mortality. On the other hand, heavy consumption has been associated with deleterious CV outcomes including increased mortality. However, the evidence is based from observational and population-based studies where risk of confounding cannot be excluded even after meticulous methodological approaches. This is compounded by conflicting data such as higher risk of certain CV diseases like HF in former drinkers compared to abstainers. Further, Mendelian randomization studies using genetic polymorphisms in enzymes have recently questioned the beneficial association of low-moderate drinking with CV system. There has been substantial and consistent evidence that light to moderate alcohol consumption have beneficial effect on overall cardiovascular profile and mortality. However, there are considerable limitations in the reported literature to determine a strong causality of a protective effect of moderate alcohol consumption by itself. Further robust studies or possibly a well-structured randomized controlled could bring an end to this debate.

Pathogenesis of ethanol-induced esophageal cancer

Ethanol is one of the major risk factors for esophageal cancer. The main mechanisms of ethanol induced esophageal cancer include the direct carcinogenesis of acetaldehyde, the genetic polymorphism of enzymes related to alcohol metabolism, the carcinogenic effect of reactive oxygen species, the disorder of nutrient metabolism induced by ethanol, and the synergistic effect of ethanol and tobacco. Key words: Esophageal neoplasms; Ethanol

Species differences between rat and human in vitro metabolite profile, in vivo predicted clearance, CYP450 inhibition and CYP450 isoforms that metabolize benzanthrone: Implications in risk assessment

Benzanthrone (BNZ) is a polycyclic aromatic hydrocarbon found in industrial effluent causing skin, respiratory, gastrointestinal, genitourinary, nervous and hemopoietic toxicity. While its toxicity has been well studied, its metabolism in humans has not been investigated. The aim of this study was to characterize species differences in the in vitro metabolism of BNZ in rat and human liver microsomes and to identify the CYP isoforms involved in its metabolism. Upon incubation in liver microsomes, BNZ was found to be a direct substrate of phase I metabolism in both rat and human, undergoing oxidation and reduction. The Km in rat, 11.62 ± 1.49 μM, was two-fold higher than humans (5.97 ± 0.83 μM) suggesting higher affinity for human CYPs. Further, incubation with human rCYPs, BNZ was found to be substrate of multiple CYPs. The predicted in vivo hepatic clearance was 63.55 and 18.91 mL/min/kg in rat and human, respectively, indicating BNZ to be a high clearance compound. BNZ was found to be a moderate inhibitor of human CYP1A2. BNZ metabolism by multiple CYPs indicates that single enzyme genetic polymorphism is unlikely to have profound effect on the toxicokinetics of BNZ and default uncertainty factor of 3.16 might be sufficient to capture the intraspecies kinetic variability.

Virtual Clinical Studies to Examine the Probability Distribution of the AUC at Target Tissues Using Physiologically-Based Pharmacokinetic Modeling: Application to Analyses of the Effect of Genetic Polymorphism of Enzymes and Transporters on Irinotecan Induced Side Effects

PurposeTo establish a physiologically-based pharmacokinetic (PBPK) model for analyzing the factors associated with side effects of irinotecan by using a computer-based virtual clinical study (VCS) because many controversial associations between various genetic polymorphisms and side effects of irinotecan have been reported.MethodsTo optimize biochemical parameters of irinotecan and its metabolites in the PBPK modeling, a Cluster Newton method was introduced. In the VCS, virtual patients were generated considering the inter-individual variability and genetic polymorphisms of enzymes and transporters.ResultsApproximately 30 sets of parameters of the PBPK model gave good reproduction of the pharmacokinetics of irinotecan and its metabolites. Of these, 19 sets gave relatively good description of the effect of UGT1A1 *28 and SLCO1B1 c.521T>C polymorphism on the SN-38 plasma concentration, neutropenia, and diarrhea observed in clinical studies reported mainly by Teft et al. (Br J Cancer. 112(5):857-65, 20). VCS also indicated that the frequency of significant association of biliary index with diarrhea was higher than that of UGT1A1 *28 polymorphism.ConclusionThe VCS confirmed the importance of genetic polymorphisms of UGT1A1 *28 and SLCO1B1 c.521T>C in the irinotecan induced side effects. The VCS also indicated that biliary index is a better biomarker of diarrhea than UGT1A1 *28 polymorphism.