Genetic polymorphism of CYP1A2 increases the risk of myocardial infarction

The effect of caffeine on exercise performance is not influenced by ADORA2A genotypes, alone or pooled with CYP1A2 genotypes, in adolescent athletes

PURPOSE

This study investigated the influence of the different genotypes of ADORA2A (1976 C > T, rs 5751876), alone or pooled with CYP1A2 (163 C > A rs 762551) genotypes, on the ergogenic effects of caffeine (CAF) on various aspects of physical performance in male adolescent athletes.

METHODS

Ninety male adolescent athletes (age = 15.5 ± 2 years) were classified according to their genotypes for 1976 C > T ADORA2A (TT homozygous or C_ADORA2A allele carriers) and 163 C > A CYP1A2 (AA homozygous or C_CYP1A2 allele carriers). Participants were further divided in four groups (1-TT_ADORA2A + AA_CYP1A2; 2-TT_ADORA2A + AC/CC_CYP1A2; 3-AA_CYP1A2 + CT/CC_ADORA2A;4-AC/CC_CYP1A2 + CT/CC_ADORA2A). Using a randomized, crossover, counterbalanced, and double-blind design, participants ingested CAF (6 mg kg^-1) or a placebo (PLA, 300 mg of cellulose) one hour before performing a sequence of physical tests: handgrip strength, agility test, countermovement jump (CMJ), Spike Jump (SJ), sit-ups, push-ups, and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1).

RESULTS

CAF enhanced handgrip strength (CAF: 35.0 ± 9.2 kg force; PLA: 33.5 ± 8.9 kg force; p = 0.050), CMJ height (CAF: 49.6 ± 12.3 cm; PLA: 48.3 ± 13.6 cm; p = 0.013), SJ height (CAF: 54.7 ± 13.3 cm; PLA: 53.1 ± 14.8 cm; p = 0.013), number of sit-ups (CAF: 37 ± 8; PLA: 35 ± 8; p = 0.001), and distance covered on the Yoyo IR1 test (CAF: 991.6 ± 371.0 m; PLA: 896.0 ± 311.0 m; p = 0.001), This CAF-induced improvement on exercise performance was, however, independent of genotypes groups (all p > 0.05). CAF had no effect on agility (CAF: 15.8 ± 1.2 s; PLA: 15.9 ± 1.3 s; p = 0.070) and push-up (CAF: 26.6 ± 12.0; PLA: 25.0 ± 11.0; p = 0.280) tests.

CONCLUSION

The acute caffeine intake of 6.0 mg.kg^-1 improves several aspects of physical performance, which seems to be independent of ADORA2A genotypes, alone or in combination with CYP1A2 genotypes.

The influence of the CYP1A2-163 C>A polymorphism on the hemostatic response to exercise following caffeine supplementation

BACKGROUND

Prior work from our group suggests that caffeine increases thrombotic potential after acute exercise. The aim of this study was to determine if hemostatic responses to exercise affected by caffeine are influenced by the CYP1A2-163 C>A polymorphism.

METHODS

Forty-two healthy men performed two trials in which a graded maximal exercise test was completed one hour after consuming either 6 mg/kg of caffeine or placebo. Subjects were categorized as possessing the C allele (N.=21) or being homozygous for the A allele (N.=21).

RESULTS

Factor VIII increased more (265%) during exercise in the caffeinated condition than the placebo condition (178%) (P<0.05). Tissue plasminogen activator (tPA) activity also increased more following caffeine as compared to placebo (increase of 8.70±4.32 IU/mL vs. 6.77±3.79 IU/mL respectively, P<0.05). There was no treatment × genotype or treatment × time × genotype interactions.

CONCLUSIONS

Although caffeine increases factor VIII and tPA responses to maximal exercise, these changes are not influenced by the CYP1A2-163 C>A polymorphism.

Interactions between genetic and lifestyle factors on cardiometabolic disease-related outcomes in Latin American and Caribbean populations: A systematic review

Introduction

The prevalence of cardiometabolic diseases has increased in Latin American and the Caribbean populations (LACP). To identify gene-lifestyle interactions that modify the risk of cardiometabolic diseases in LACP, a systematic search using 11 search engines was conducted up to May 2022.

Methods

Eligible studies were observational and interventional studies in either English, Spanish, or Portuguese. A total of 26,171 publications were screened for title and abstract; of these, 101 potential studies were evaluated for eligibility, and 74 articles were included in this study following full-text screening and risk of bias assessment. The Appraisal tool for Cross-Sectional Studies (AXIS) and the Risk Of Bias In Non-Randomized Studies-of Interventions (ROBINS-I) assessment tool were used to assess the methodological quality and risk of bias of the included studies.

Results

We identified 122 significant interactions between genetic and lifestyle factors on cardiometabolic traits and the vast majority of studies come from Brazil (29), Mexico (15) and Costa Rica (12) with FTO, APOE, and TCF7L2 being the most studied genes. The results of the gene-lifestyle interactions suggest effects which are population-, gender-, and ethnic-specific. Most of the gene-lifestyle interactions were conducted once, necessitating replication to reinforce these results.

Discussion

The findings of this review indicate that 27 out of 33 LACP have not conducted gene-lifestyle interaction studies and only five studies have been undertaken in low-socioeconomic settings. Most of the studies were cross-sectional, indicating a need for longitudinal/prospective studies. Future gene-lifestyle interaction studies will need to replicate primary research of already studied genetic variants to enable comparison, and to explore the interactions between genetic and other lifestyle factors such as those conditioned by socioeconomic factors and the built environment. The protocol has been registered on PROSPERO, number CRD42022308488.

Systematic review registration

https://clinicaltrials.gov, identifier CRD420223 08488.

Can the Brazilian Caffeine Expectancy Questionnaires Differentiate the CYP1A2 and ADORA2A Gene Polymorphisms?-An Exploratory Study with Brazilian Athletes

This study investigated the ability of the Brazilian Caffeine Expectancy Questionnaire (CaffEQ-BR), full and brief versions, to differentiate genetic profiles regarding the polymorphisms of the CYP1A2 (rs 762551) and ADORA2A (rs 5751876) genes in a cohort of Brazilian athletes. One-hundred and fifty participants were genotyped for CYP1A2 and ADORA2A. After the recruitment and selection phase, 71 (90% male and 10% female, regular caffeine consumers) completed the CaffEQ-BR questionnaires and a self-report online questionnaire concerning sociodemographic data, general health status, and frequency of caffeine consumption. The order of completion of the CaffEQ-BR questionnaires was counterbalanced. The concordance between the full and brief versions of the CaffEQ-BR was analyzed using the intraclass correlation coefficient (ICC). To determine the discriminatory capacity of the questionnaires for genotype, the receiver operating characteristic (ROC) curve was applied for sensitivity and specificity (significance level of 5%). Mean caffeine intake was 244 ± 161 mg·day−1. The frequency of AA genotypes for CYP1A2 was 47.9% (n = 34) and 52.1% (n = 37) for C-allele carriers (AC and CC). The frequencies of TT genotypes for ADORA2A were 22.7% (n = 15) and 77.3% (n = 51) for C-allele carriers (TC and CC). All CaffEQ-BR factors, for the full and brief versions, were ICCs > 0.75, except for factor 6 (anxiety/negative effects; ICC = 0.60), and presented ROC curve values from 0.464 to 0.624 and 0.443 to 0.575 for CYP1A2 and ADORA2A. Overall, the CaffEQ-BR (full and brief versions) did not show discriminatory capacity for CYP1A2 and ADORA2A gene polymorphisms. In conclusion, the CaffEQ-BR was not able to differentiate genotypes for the CYP1A2 or ADORA2A genes in this group of Brazilian athletes.

Ancestral sequence reconstruction of a cytochrome P450 family involved in chemical defence reveals the functional evolution of a promiscuous, xenobiotic-metabolizing enzyme in vertebrates

The cytochrome P450 family 1 enzymes (CYP1s) are a diverse family of hemoprotein monooxygenases, which metabolize many xenobiotics including numerous environmental carcinogens. However, their historical function and evolution remain largely unstudied. Here we investigate CYP1 evolution via the reconstruction and characterization of the vertebrate CYP1 ancestors. Younger ancestors and extant forms generally demonstrated higher activity toward typical CYP1 xenobiotic and steroid substrates than older ancestors, suggesting significant diversification away from the original CYP1 function. Caffeine metabolism appears to be a recently evolved trait of the CYP1A subfamily, observed in the mammalian CYP1A lineage, and may parallel the recent evolution of caffeine synthesis in multiple separate plant species. Likewise, the aryl hydrocarbon receptor agonist, 6-formylindolo[3,2-b]carbazole (FICZ) was metabolized to a greater extent by certain younger ancestors and extant forms, suggesting that activity toward FICZ increased in specific CYP1 evolutionary branches, a process that may have occurred in parallel to the exploitation of land where UV-exposure was higher than in aquatic environments. As observed with previous reconstructions of P450 enzymes, thermostability correlated with evolutionary age; the oldest ancestor was up to 35 °C more thermostable than the extant forms, with a ¹⁰T₅₀ (temperature at which 50% of the hemoprotein remains intact after 10 min) of 71 °C. This robustness may have facilitated evolutionary diversification of the CYP1s by buffering the destabilizing effects of mutations that conferred novel functions, a phenomenon which may also be useful in exploiting the catalytic versatility of these ancestral enzymes for commercial application as biocatalysts.

Contribution of CYP19A1, CYP1A1, and CYP1A2 polymorphisms in coronary heart disease risk among the Chinese Han population

The previous study has pointed to that endogenous CYP metabolites play an important role in the pathogenesis of coronary heart disease (CHD). The study aimed to identify the association of CYP19A1, CYP1A1, and CYP1A2 polymorphisms with CHD susceptibility in a Chinese Han population. A total of 960 genetically unrelated participants consist of 480 CHD patients and 480 healthy controls were enrolled. Nine SNPs in CYP19A1, CYP1A1, and CYP1A2 were randomly selected and genotyped using the Agena MassARRAY platform. Logistic regression analysis was used for the relationship between selected SNPs and CHD susceptibility by calculating odds ratios (OR) with 95% confidence intervals (CI) adjusted for age and gender. The distribution of clinical characteristics in different genotypes was evaluated by one-way analysis of variance (ANOVA). CYP1A2 rs2470890 TT genotype had a higher CHD risk compared with CC genotype (OR = 3.06, p = 0.032) or CC-CT genotype (OR = 3.04, p = 0.033). Moreover, the contribution of CYP19A1 and CYP1A2 polymorphisms to CHD susceptibility was associated with age, gender, and clinical phenotypes (course of the disease and Gensini score). Besides, CYP1A2 rs762551 was related to serum levels of red blood cell, triglyceride, total cholesterol, and low-density lipoprotein cholesterol (LDL-C, p < 0.05). Our findings provided scientific evidence about CYP19A1, CYP1A1, and CYP1A2 polymorphisms on CHD incidence.

Novel Synthetic Analogues of 19(S/R)-Hydroxyeicosatetraenoic Acid Exhibit Noncompetitive Inhibitory Effect on the Activity of Cytochrome P450 1A1 and 1B1

BACKGROUND AND OBJECTIVES

Cytochrome P450 (CYP) 1A1 and CYP1B1 enzymes play a significant role in the pathogenesis of cancer and cardiovascular diseases (CVD) such as cardiac hypertrophy and heart failure. Previously, we have demonstrated that R- and S-enantiomers of 19-hydroxyeicosatetraenoic acid (19-HETE), an arachidonic acid endogenous metabolite, enantioselectively inhibit CYP1B1. The current study was conducted to test the possible inhibitory effect of novel synthetic analogues of R- and S-enantiomers of 19-HETE on the activity of CYP1A1, CYP1A2, and CYP1B1.

METHODS

The O-dealkylation rate of 7-ethoxyresorufin (EROD) by recombinant human CYP1A1 and CYP1B1, in addition to the O-dealkylation rate of 7-methoxyresorufin (MROD) by recombinant human CYP1A2, were measured in the absence and presence of varying concentrations (0-40 nM) of the synthetic analogues of 19(R)- and 19(S)-HETE. Also, the possible inhibitory effect of both analogues on the catalytic activity of EROD and MROD, using RL-14 cells and human liver microsomes, was assessed.

RESULTS

The results showed that both synthetic analogues of 19(R)- and 19(S)-HETE exhibited direct inhibitory effects on the activity of CYP1A1 and CYP1B1, while they had no significant effect on CYP1A2 activity. Nonlinear regression analysis and comparisons showed that the mode of inhibition for both analogues is noncompetitive inhibition of CYP1A1 and CYP1B1 enzymes. Also, nonlinear regression analysis and Dixon plots showed that the R- and S-analogues have K_I values of 15.7 ± 4.4 and 6.1 ± 1.5 nM for CYP1A1 and 26.1 ± 2.9 and 9.1 ± 1.8 nM for CYP1B1, respectively. Moreover, both analogues were able to inhibit EROD and MROD activities in a cell-based assay and human liver microsomes.

CONCLUSIONS

Therefore, the synthetic analogues of 19-HETE could be considered as a novel therapeutic approach in the treatment of cancer and CVD.

Biological roles of cytochrome P450 1A1, 1A2, and 1B1 enzymes

Human cytochrome P450 enzymes (CYPs) play a critical role in various biological processes and human diseases. CYP1 family members, including CYP1A1, CYP1A2, and CYP1B1, are induced by aryl hydrocarbon receptors (AhRs). The binding of ligands such as polycyclic aromatic hydrocarbons activates the AhRs, which are involved in the metabolism (including oxidation) of various endogenous or exogenous substrates. The ligands that induce CYP1 expression are reported to be carcinogenic xenobiotics. Hence, CYP1 enzymes are correlated with the pathogenesis of cancers. Various endogenous substrates are involved in the metabolism of steroid hormones, eicosanoids, and other biological molecules that mediate the pathogenesis of several human diseases. Additionally, CYP1s metabolize and activate/inactivate therapeutic drugs, especially, anti-cancer agents. As the metabolism of drugs determines their therapeutic efficacy, CYP1s can determine the susceptibility of patients to some drugs. Thus, understanding the role of CYP1s in diseases and establishing novel and efficient therapeutic strategies based on CYP1s have piqued the interest of the scientific community.

Caffeine improves various aspects of athletic performance in adolescents independent of their 163 C > A CYP1A2 genotypes

PURPOSE

The purpose of this study was to investigate whether variations in 163 C > A CYP1A2 genotypes (rs 762 551) (AA, AC, and CC) modify the ergogenic effects of caffeine (CAF) on strength, power, muscular endurance, agility, and endurance in adolescent athletes.

METHODS

One hundred adolescents (age = 15 ± 2 years) were recruited. Participants ingested CAF (6 mg.kg^-1 ) or placebo (PLA, 300 mg of cellulose) 1 hour before performing a sequence of physical tests: handgrip strength, vertical jumps, agility test, sit-ups, push-ups, and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1).

RESULTS

Compared to PLA, CAF enhanced (P < .05) sit-up (CAF = 37 ± 9; PLA = 35 ± 8 repetitions) and push-up repetitions (CAF = 26 ± 11; PLA = 24 ± 11 repetitions), and increased distance covered in Yo-Yo IR1 test (CAF = 1010.4 ± 378.9; PLA = 903.2 ± 325.7 m). There was no influence of CAF on handgrip strength (CAF = 35.1 ± 8.9; PLA = 33.7 ± 8.7 kgf), countermovement jump height (CAF = 49.3 ± 12.6; PLA = 47.9 ± 13.8 cm), spike jump height (CAF = 54.2 ± 13.6; PLA = 52.9 ± 14.5 cm), and time in agility test (CAF = 15.8 ± 1.1; PLA = 15.9 ± 1.3 s, P > .05). When present, the ergogenic effect of CAF was not dependent of genotype.

CONCLUSION

CAF improves muscular endurance and aerobic performance in adolescent athletes, regardless of their 163 C > A CYP1A2 genotype.

Implementation of pharmacogenetics in a clozapine treatment resistant patient: a case report

We report the case of a young Caucasian male with disorganized chronic schizophrenia, an active smoker and nonresponder to 400 mg of clozapine/day. Therapeutic clozapine monitoring was analyzed revealing a low clozapine:norclozapine ratio. An additional pharmacogenetic test was carried out showing that the patient carried *1F variant ( CYP1A2 gene), which has been associated with nonresponse to clozapine in smoker patients. A genetic variation in the SLC6A4 gene was also found, which could be related to the poor response to clozapine. The remainder of the genes analyzed ( CYP2D6, ABCB1 and HTR2A) were not directly associated with the patient’s phenotype. The dose of clozapine was increased to 600 mg/day, reaching the therapeutic range. This case shows how pharmacogenetics can help in understanding the value of plasma levels to provide clinical improvement.

Subterminal hydroxyeicosatetraenoic acids: Crucial lipid mediators in normal physiology and disease states

Cytochrome P450 (P450) enzymes are superfamily of monooxygenases that hold the utmost diversity of substrate structures and catalytic reaction forms amongst all other enzymes. P450 enzymes metabolize arachidonic acid (AA) to a wide array of biologically active lipid mediators. P450-mediated AA metabolites have a significant role in normal physiological and pathophysiological conditions, hence they could be promising therapeutic targets in different disease states. P450 monooxygenases mediate the (ω-n)-hydroxylation reactions, which involve the introduction of a hydroxyl group to the carbon skeleton of AA, forming subterminal hydroxyeicosatetraenoic acids (HETEs). In the current review, we specified different P450 isozymes implicated in the formation of subterminal HETEs in varied tissues. In addition, we focused on the role of subterminal HETEs namely 19-HETE, 16-HETE, 17-HETE and 18-HETE in different organs, importantly the kidneys, heart, liver and brain. Furthermore, we highlighted their role in hypertension, acute coronary syndrome, diabetic retinopathy, non-alcoholic fatty liver disease, ischemic stroke as well as inflammatory diseases. Since each member of subterminal HETEs exist as R and S enantiomer, we addressed the issue of stereoselectivity related to the formation and differential effects of these enantiomers. In conclusion, elucidation of different roles of subterminal HETEs in normal and disease states leads to identification of novel therapeutic targets and development of new therapeutic modalities in different disease states.

The clinical toxicology of caffeine: A review and case study

Caffeine is a widely recognized psychostimulant compound with a long history of consumption by humans. While it has received a significant amount of attention there is still much to be learned with respect to its toxicology in humans, especially in cases of overdose. A review of the history of consumption and the clinical toxicology of caffeine including clinical features, pharmacokinetics, toxicokinetics, a thorough examination of mechanism of action and management/treatment strategies are undertaken. While higher (i.e., several grams) quantities of caffeine are known to cause toxicity and potentially lethality, cases of mainly younger individuals who have experienced severe side effects and death despite consuming doses not otherwise known to cause such harm is troubling and deserves further study. An attempted case reconstruction is performed in an effort to shed light on this issue with a focus on the pharmacokinetics and pharmacodynamics of caffeine.

Cytochrome P450: Polymorphisms and Roles in Cancer, Diabetes and Atherosclerosis

Cytochromes P450s (CYPs) constitute a superfamily of enzymes that catalyze the metabolism of drugs and other substances. Endogenous substrates of CYPs include eicosanoids, estradiol, arachidonic acids, cholesterol, vitamin D and neurotransmitters. Exogenous substrates of CYPs include the polycyclic aromatic hydrocarbons and about 80% of currently used drugs. Some isoforms can activate procarcinogens to ultimate carcinogens. Genetic polymorphisms of CYPs may affect the enzyme catalytic activity and have been reported among different populations to be associated with various diseases and adverse drug reactions. With regard of drug metabolism, phenotypes for CYP polymorphism range from ultrarapid to poor metabolizers. In this review, we discuss some of the most clinically important CYPs isoforms (CYP2D6, CYP2A6, CYP2C19, CYP2C9, CYP1B1 and CYP1A2) with respect to gene polymorphisms and drug metabolism. Moreover, we review the role of CYPs in renal, lung, breast and prostate cancers and also discuss their significance for atherosclerosis and type 2 diabetes mellitus.

Network pharmacology-based prediction of active compounds and molecular targets in Yijin-Tang acting on hyperlipidaemia and atherosclerosis

ETHNOPHARMACOLOGICAL RELEVANCE

Yijin-Tang (YJT) is a traditional prescription for the treatment of hyperlipidaemia, atherosclerosis and other ailments related to dampness phlegm, a typical pathological symptom of abnormal body fluid metabolism in Traditional Korean Medicine. However, a holistic network pharmacology approach to understanding the therapeutic mechanisms underlying hyperlipidaemia and atherosclerosis has not been pursued.

AIM OF THE STUDY

To examine the network pharmacological potential effects of YJT on hyperlipidaemia and atherosclerosis, we analysed components, performed target prediction and network analysis, and investigated interacting pathways using a network pharmacology approach.

MATERIALS AND METHODS

Information on compounds in herbal medicines was obtained from public databases, and oral bioavailability and drug-likeness was screened using absorption, distribution, metabolism, and excretion (ADME) criteria. Correlations between compounds and genes were linked using the STITCH database, and genes related to hyperlipidaemia and atherosclerosis were gathered using the GeneCards database. Human genes were identified and subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

RESULTS

Network analysis identified 447 compounds in five herbal medicines that were subjected to ADME screening, and 21 compounds and 57 genes formed the main pathways linked to hyperlipidaemia and atherosclerosis. Among them, 10 compounds (naringenin, nobiletin, hesperidin, galangin, glycyrrhizin, homogentisic acid, stigmasterol, 6-gingerol, quercetin and glabridin) were linked to more than four genes, and are bioactive compounds and key chemicals. Core genes in this network were CASP3, CYP1A1, CYP1A2, MMP2 and MMP9. The compound-target gene network revealed close interactions between multiple components and multiple targets, and facilitates a better understanding of the potential therapeutic effects of YJT.

CONCLUSIONS

Pharmacological network analysis can help to explain the potential effects of YJT for treating dampness phlegm-related diseases such as hyperlipidaemia and atherosclerosis.

NOTCH4 is a possible novel susceptibility gene for dilated cardiomyopathy in the Chinese population: A case-control study

BACKGROUND

The incidence of dilated cardiomyopathy (DCM) has increased in recent years, and many studies have sought to further improve the general understanding of this condition. Previous studies have demonstrated that some single nucleotide polymorphisms (SNPs) associated with systemic lupus erythematosus also affect susceptibility to DCM, suggesting that immune-related diseases may share similar genetic susceptibility. Recent large-scale and genome-wide association studies have identified NCR3, NOTCH4, CYP1A2, ITGA1, OPRM1, ST8SIA2, and LINC00704 as genetic risk factors associated with cardiac manifestations of neonatal lupus. Here, we aimed to determine whether these SNPs conferred susceptibility to DCM in the Chinese Han population.

METHODS

We investigated the relationship between these polymorphisms and DCM risk in 273 patients with DCM and 548 healthy controls. Genotyping was performed using MassArray iPLEX system.

RESULTS

Logistic regression analysis indicated that the T allele of rs3134942 in NOTCH4 gene increased the risk of DCM by 61% compared with the G allele (P_a  = 6.57 × 10^-3 ). The SNP rs3134942 was also significantly associated with increased DCM risk in the additive (P_a  = 6.57 × 10^-3 ) and dominant models (P_a  = 1.01 × 10^-2 ). Additionally, rs2472299 in CYP1A2 gene showed suggestive association with reduced risk of DCM in the dominant model (P_a  = 4.24 × 10^-2 ) and was correlated with smoking status in patients with DCM (P_a  = 1.56 × 10^-2 ).

CONCLUSIONS

Our findings suggested that rs3134942 in NOTCH4 may be involved in DCM risk. Further, studies in larger and ethnically diverse populations are required to confirm the results reported in this study.

Gene-gene interaction between PPARG and CYP1A1 gene on coronary artery disease in the Chinese Han Population

AIMS

To observe the influence of the peroxisome proliferator-activator receptor-G (PPAR-G) gene and cytochrome P4501A1 (CYP1A1) single-nucleotide polymorphisms (SNPs), and interactions among several SNPs on coronary artery disease (CAD) risk.

METHODS

A total of 1106 participants (including 583 males and 523 females) including 550 CAD patients and 556 control subjects were recruited in this study, and the mean age for these participants was 55.5 ± 11.8 years old. Logistic regression was used to observe association of SNP within PPARG and CYP1A1 with CAD risk and GMDR model was used to screen the best interaction combinations.

RESULTS

CAD susceptibility was higher in those with homozygous mutant of rs10865710, rs1805192 and rs4646903 than those with wild-type homozygotes, OR (95%CI) were 1.47 (1.15-1.92), 1.69 (1.27-2.09) and 1.72 (1.35-2.32), respectively. We also found a significant two-locus model involving rs1805192 and rs4646903 (p = 0.0107), and the cross-validation consistency of this locus model was 10 of 10, the testing accuracy of this model is 62.17%. Logistic regression shown that CAD risk was the highest in those with rs1805192- Pro/Ala or Ala/Ala and rs4646903- AG+GG genotype, and was lowest in those with rs1805192- Pro/ Pro and rs4646903- AA genotype, OR(95%CI) = 3.56 (1.91-5.42).

CONCLUSIONS

Polymorphism in rs10865710, rs1805192 and rs4646903 and interaction between rs1805192 and rs4646903 were related with increased CAD susceptibility.

CYP1A2*1F Gene Variant, Alkaline Salt Tea Intake and Risk of Esophageal Squamous Cell Carcinoma

Unlike many other cancers, the relationship of CYP1A2*1F (rs762551) polymorphism with esophageal squamous cell carcinoma (ESCC) risk has not been assessed so far. To evaluate its association with ESCC, we conducted a case control study in Kashmir, India, a high risk region. We recruited 404 histopathologically confirmed ESCC cases and 404 controls, individually matched for sex, age and residence to the respective cases. Information was obtained on dietary, lifestyle and environmental factors in face to face interviews using a structured questionnaire from each subject. Genotypes were analyzed by polymerase chain reaction, restriction fragment length polymorphism and sequencing randomly selected samples. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). We found that mutant genotype (AA) of CYP1A2*1F polymorphism was associated with ESCC risk (OR = 3.11; 95% CI: 1.72-5.36). A very strong ESCC risk was observed in subjects who drank >1250 ml of salt tea daily and harbored mutant genotype of CYP1A2*1F (OR = 14.51; 95% CI: 5.33-39.47). The study indicates that CYP1A2*1F polymorphism is associated with ESCC risk and the risk is modified in salt drinkers. However, more replicative and mechanistic studies are needed to substantiate the findings.

Associations between Rs4244285 and Rs762551 gene polymorphisms and age-related macular degeneration

BACKGROUND

Age-related macular degeneration is the leading cause of blindness in elderly individuals in developed countries. The etiology and pathophysiology of age-related macular degeneration have not been elucidated yet. Knowing that the main pathological change of age-related macular degeneration is formation of drusen containing about 40% of lipids, there have been attempts to find associations between age-related macular degeneration and genes controlling lipid metabolism.

PURPOSE

To determine the frequency of CYP2C19 (G681A) Rs4244285 and CYP1A2 (-163C>A) Rs762551 genotypes in patients with age-related macular degeneration.

METHODS

The study enrolled 150 patients with early age-related macular degeneration and 296 age- and gender-matched healthy controls. The genotyping of Rs4244285 and Rs762551 was carried out by using the real-time polymerase chain reaction method.

RESULTS

The CYP1A2 (-163C>A) Rs762551 C/C genotype was more frequently detected in patients with age-related macular degeneration than in the control group (32.7% vs. 21.6%, p = 0.011) and was associated with an increased risk of developing early age-related macular degeneration (OR = 1.759, 95% CI: 1.133-2.729; p = 0.012). The CYP1A2 (-163C>A) Rs762551 C/A genotype was more frequently documented in the control group compared with patients with age-related macular degeneration (46.3% vs. 30.7%, p = 0.002) and was associated with a decreased risk of having age-related macular degeneration (OR = 0.580. 95% CI: 0.362-0.929, p = 0.023) in the co-dominant model.

CONCLUSION

The study showed that the CYP1A2 (-163C>A) Rs762551 C/C genotype was associated with an increased risk of age-related macular degeneration.

Pharmacogenetic research activity in Central America and the Caribbean: a systematic review

AIM

The present review was aimed at analyzing the pharmacogenetic scientific activity in Central America and the Caribbean.

MATERIALS & METHODS

A literature search for pharmacogenetic studies in each country of the region was conducted on three databases using a list of the most relevant pharmacogenetic biomarkers including 'phenotyping probe drugs' for major drug metabolizing enzymes. The review included 132 papers involving 47 biomarkers and 35,079 subjects (11,129 healthy volunteers and 23,950 patients).

RESULTS

The country with the most intensive pharmacogenetic research was Costa Rica. The most studied medical therapeutic area was oncology, and the most investigated biomarkers were CYP2D6 and HLA-A/B. Conclusion: Research activity on pharmacogenetics in Central American and the Caribbean populations is limited or absent. Therefore, strategies to promote effective collaborations, and foster interregional initiatives and research efforts among countries from the region could help for the rational clinical implementation of pharmacogenetics and personalized medicine.

Moving towards Specific Nutrigenetic Recommendation Algorithms: Caffeine, Genetic Variation and Cardiovascular Risk

Recent research has indicated that part of the interindividual variability in cardiovascular responses to caffeine has a genetic basis. Therefore, knowledge of the individual's genetic constitution may allow an individual tailoring of dietary advice for the use of caffeine-containing beverages, yielding an example of the potential of practical translation of nutrigenetic information. This paper reviews the basis for possible nutrigenetic recommendations on the consumption of caffeine, discussing the current gaps in knowledge but also proposing a mode of action in this research area, which may be transposed to other types of similar recommendations.

Influence of a CYP1A2 polymorphism on post-exercise heart rate variability in response to caffeine intake: a double-blind, placebo-controlled trial

BACKGROUND

Proposed differences in caffeine metabolism due to the CYP1A2*1F polymorphism have been linked to variations in cardiovascular disease risk.

AIMS

We examined the influence of a CYP1A2*1F polymorphism on post-exercise heart rate variability (HRV) in response to caffeine intake.

METHODS

Volunteers were identified as A/A homozygotes (A/A; 4 females and 7 males; age: 25.3 ± 4.1 years; BMI: 25.9 ± 4.4 kg/m²) or C allele carriers (C allele; 3 females and 6 males; age: 25.5 ± 2.8 years; BMI: 26.6 ± 5.0 kg/m²) for participation in a repeated measures, counterbalanced, double-blind, placebo-controlled trial. Participants chewed three pieces of gum containing either caffeine (CAF) (100 mg/piece) or placebo for 5 min. Thereafter, participants cycled for 15 min at 75 % of their peak oxygen consumption. Eight HRV indices computed during 5 min at baseline (BASE), 0-5 min after exercise (POST1), and 5-10 min after exercise (POST2) were used for analysis.

RESULTS

No significant group differences were detected in HRV indices at BASE, POST1, or POST2 during both trials (p > 0.05). Rate of recovery (POST2-POST1) for the square root of the mean of squared differences between successive RR intervals (RMSSD) was significantly different between A/A (6.0 ± 2.5 ms) and C allele (3.6 ± 2.5 ms) groups during the CAF trial (p = 0.048).

CONCLUSIONS

Rate of RMSSD recovery was the only variable influenced by the CYP1A2*IF polymorphism during post-exercise in response to caffeine intake. Thus, the CYP1A2*1F polymorphism did not overtly influence the effects of caffeine intake on post-exercise HRV.

Preclinical Pharmacokinetics and Pharmacodynamics and Content Analysis of Gnetol in Foodstuffs

Studies were undertaken to evaluate the bioavailability in rats and content analysis of gnetol in Gnetum gnemon products reported to contain gnetol and to examine the pharmacological properties of gnetol in in vitro models including anti-inflammatory/analgesic, antidiabetic, anti-adipogenesis, and anticancer activity. Male Sprague-Dawley rats were cannulated and dosed either intravenously with gnetol (10 mg/kg) or orally (100 mg/kg). Various methanolic extractions of G. gnemon products were quantified. Gnetol's effect on cell viability in selected cell lines with or without inflammatory stimulus was assessed. α-Amylase and α-glucosidase inhibition was evaluated. Cyclooxygenase (COX)-1, COX-2, and histone deacetylase inhibition and adipogenesis inhibition were examined. After oral and intravenous administration, gnetol was detected in both serum and urine as the parent compound and as a glucuronidated metabolite. The bioavailability of gnetol was determined to be 6%. Gnetol is rapidly glucuronidated and is excreted in urine and via nonrenal routes. Gnetol was found to exist as an aglycone and as a glycoside in G. gnemon products. Gnetol showed concentration-dependent reductions in cell viability in cancer cell lines with greatest activity in colorectal cancer and potent COX-1, histone deacetylase, and weak COX-2 activities along with limited reduction in inflammation. Gnetol also possessed concentration-dependent alpha-amylase, alpha-glucosidase, and adipogenesis activities. Pretreatment of mice with gnetol was able to increase the latency period to response in analgesia models.

Relationship between CYP17A1 genetic polymorphism and coronary artery disease in a Chinese Han population

BACKGROUND

CYP17A1 gene encodes P450c17 proteins, which is a key enzyme that catalyzes the formation of sex hormones. Many clinical studies showed that sex hormones levels play an important role in the pathogenesis of coronary artery disease (CAD). However, the relationship between CYP17A1 genetic polymorphisms and CAD remains unclear. The aim of this study was to investigate the association of CYP17A1 genetic polymorphisms with CAD in a Han population of China.

METHODS

A total of 997 people include 490 patients and 507 controls were selected for the present study. Five single-nucleotide polymorphisms (SNPs) (rs4919686, rs1004467, rs4919687, rs10786712, and rs2486758) were genotyped by using the real-time PCR (TaqMan) method.

RESULTS

For men, the rs10786712 was found to be associated with CAD in a recessive model (P=0.016), after adjustment of the major confounding factors, the significant difference was retained (OR=1.644, 95% confidence interval [CI]: 1.087-2.488, P=0.019). For women, the rs1004467 was also found to be associated with CAD in a dominant model (P=0.038), the difference remained statistically significant after multivariate adjustment (OR=1.623, 95% CI: 1.023-2.576, P=0.040). The distribution of rs4919687 genotypes showed a significant difference between CAD and control participants in a recessive model (P=0.019), the significant difference was retained after adjustment for covariates (OR=0.417, 95% CI: 0.188-0.926, P=0.032).

CONCLUSION

Rs1004467, rs4919687, rs10786712 of CYP17A1 gene are associated with CAD in Han population of China. The TT genotype of rs10786712 could be a protective genetic marker of CAD in men. The CC genotype of rs1004467 and the AA genotype of rs4919687 could be risk genetic markers of CAD in women. However, large sample size study including other SNPs of CYP17A1 should be performed in future studies.

Haplotype analyses of CYP17A1 genetic polymorphisms and coronary artery disease in a Uygur population

BACKGROUND

The relationship between CYP17A1 genetic polymorphisms and coronary artery disease (CAD) remains unclear. The aim of the present study was to assess the association between CYP17A1 gene polymorphism and CAD in a Chinese Uygur population.

METHODS

A total of 493 people including 266 patients and 227 controls were selected for the present study. All CAD patients and controls were genotyped for the same five single nucleotide polymorphisms (SNPs) (rs4919686, rs1004467, rs4919687, rs10786712, and rs2486758) by a real-time PCR method.

RESULTS

The rs4919686, rs1004467, and rs4919687 polymorphisms were found to be associated with CAD in genotypes, dominant model, recessive model, and allele frequency (rs4919686: all p<0.05, rs1004467: all p ≤ 0.001, rs4919687: all p<0.001); the significant difference was retained (all p<0.05) after adjustment for the major confounding factors. The overall distribution of haplotypes established by SNP1-SNP4 (in total subjects and men) and SNP1-SNP4-SNP5 (in total subjects) were significantly different between the CAD patients and the control subjects (p=0.006, men: p=0.026, and p=0.030, respectively).

CONCLUSION

Polymorphisms rs4919686, rs4919687 and rs1004467 were found to be associated with CAD in this Uygur population.

The association between CYP1A1 genetic polymorphisms and coronary artery disease in the Uygur and Han of China

Background

The cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) gene is expressed in the vascular endothelium, which metabolizes arachidonic acid into 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs). 20-HETE mediates cardiovascular homeostasis and growth response in vascular smooth muscle cells (VSMCs) as well as the anti-platelet effect. EETs are potent endogenous vasodilators and inhibitors of vascular inflammation. This study assessed the association between human CYP1A1 gene polymorphisms and coronary artery disease (CAD) in the Uygur and Han in China.

Methods

Two independent case–control studies that recruited Han (389 patients with CAD and 411 controls) and Uygur participants (293 patients with CAD and 408 controls) analyzed the relationship between CYP1A1 single nucleotide polymorphisms (SNPs: rs4886605, rs12441817, rs4646422 and rs1048943) and CAD. All patients with CAD and controls were genotyped for the four SNPs of CYP1A1 using TaqMan SNP genotyping assays.

Results

In the Uygur group, the distribution of the dominant model(CC vs CT + TT) of rs4886605 for the total sample and the males was significantly different between CAD patients and control participants (P = 0.001 and P = 0.012, respectively), The difference remained significant after a multivariate adjustment (P = 0.018, P = 0.015, respectively). The rs12441817 was also associated with CAD in a dominant model for all participants (P = 0.003) and men (P = 0.012), and the difference remained significant after a multivariate adjustment (P = 0.016, P = 0.002, respectively). However, we did not observe differences in the Uygur females and Han group with regard to the allele frequency or genotypic distribution of rs4886605 and rs12441817 between patients with CAD and control participants. Patients with CAD did not significantly differ from the control participants with regard to the distributions of rs4646422 and rs1048943 genotypes, the dominant model, the recessive model, or allele frequency in the Han and Uygur groups.

Conclusion

Both rs4886605 and rs12441817 SNPs of the CYP1A1 gene are associated with CAD in the Uygur population of China.

Cytochrome P450 and ischemic heart disease: current concepts and future directions

INTRODUCTION

The P450 enzymes (P450s) mediate the biotransformation of several drugs, steroid hormones, eicosanoids, cholesterol, vitamins, fatty acids and bile acids, many of which affect cardiovascular homeostasis. Experimental studies have demonstrated that several P450s modulate important steps in the pathogenesis of ischemic heart disease (IHD).

AREAS COVERED

This article discusses the current knowledge on i) the expression of P450s in cardiovascular and renal tissues; ii) the role of P450s in the pathophysiology of IHD, in particular the modulation of blood pressure and cardiac hypertrophy, coronary arterial tone, ischemia-reperfusion injury and the metabolism of cardiovascular drugs; iii) the available evidence from observational studies on the association between P450 gene polymorphisms and risk of myocardial infarction (MI); and iv) suggestions for further research in this area.

EXPERT OPINION

P450s exert important modulatory effects in experimental models of IHD and MI. However, observational studies have provided conflicting results on the association between P450 genetic polymorphisms and MI. Further, adequately powered studies are required to ascertain the biological and clinical impact of P450s on clinical IHD end-points, that is, fatal and nonfatal MI, revascularization and long-term outcomes post MI. Pharmacogenetic substudies of recently completed cardiovascular clinical trials might represent an alternative strategy in this context.

Considering CYP1A2 phenotype and genotype for optimizing the dose of olanzapine in the management of schizophrenia

INTRODUCTION

Schizophrenia, a mental disorder, is a debilitating condition which typically strikes young people in their early 20's. Antipsychotic medications are widely prescribed for the treatment of schizophrenia however a balancing act is necessary to provide the correct dose to each patient. It is suggested that a large number of patients discontinue antipsychotic pharmacotherapy because the treatments provided do not always reduce the positive symptoms of the disease, while many have adverse effects on the patients. This implies that neither the incorrect drug nor the optimal dosage for that patient is achieved.

AREAS COVERED

The current review investigates variability in response to olanzapine with a specific focus on the common intrinsic and extrinsic factors that influence both olanzapine and CYP1A2 activity. Furthermore, the authors discuss the utilization of phenotyping and genotyping of CYP1A2 and their potential utility in clinical practice for olanzapine dosing regimens. The authors also consider the potential of pharmacometrics compared to pharmacogenomics as a tool to personalize medicine.

EXPERT OPINION

Careful consideration must be given to the impact of a genetic variant on the disposition of a drug prior to implementing genetic 'tests' to determine response. CYP1A2 phenotypic assessment can yield important information regarding the disposition of olanzapine; however, it relies on the accuracy of the metric and the minimal impact of other metabolic pathways. The application of pharmacometrics provides an effective method to establish covariates that significantly influence olanzapine disposition which can incorporate phenotype and/or genotype.

Cytochrome P450 enzymes in drug metabolism: regulation of gene expression, enzyme activities, and impact of genetic variation

Cytochromes P450 (CYP) are a major source of variability in drug pharmacokinetics and response. Of 57 putatively functional human CYPs only about a dozen enzymes, belonging to the CYP1, 2, and 3 families, are responsible for the biotransformation of most foreign substances including 70-80% of all drugs in clinical use. The highest expressed forms in liver are CYPs 3A4, 2C9, 2C8, 2E1, and 1A2, while 2A6, 2D6, 2B6, 2C19 and 3A5 are less abundant and CYPs 2J2, 1A1, and 1B1 are mainly expressed extrahepatically. Expression of each CYP is influenced by a unique combination of mechanisms and factors including genetic polymorphisms, induction by xenobiotics, regulation by cytokines, hormones and during disease states, as well as sex, age, and others. Multiallelic genetic polymorphisms, which strongly depend on ethnicity, play a major role for the function of CYPs 2D6, 2C19, 2C9, 2B6, 3A5 and 2A6, and lead to distinct pharmacogenetic phenotypes termed as poor, intermediate, extensive, and ultrarapid metabolizers. For these CYPs, the evidence for clinical significance regarding adverse drug reactions (ADRs), drug efficacy and dose requirement is rapidly growing. Polymorphisms in CYPs 1A1, 1A2, 2C8, 2E1, 2J2, and 3A4 are generally less predictive, but new data on CYP3A4 show that predictive variants exist and that additional variants in regulatory genes or in NADPH:cytochrome P450 oxidoreductase (POR) can have an influence. Here we review the recent progress on drug metabolism activity profiles, interindividual variability and regulation of expression, and the functional and clinical impact of genetic variation in drug metabolizing P450s.

Lack of association between CYP1A1 T6235C polymorphism and coronary artery disease: evidence from a meta-analysis

A number of studies have evaluated the correlation between the cytochrome P450 1A1 (CYP1A1) T6235C polymorphism and coronary artery disease (CAD) risk, however, at present the results remain inconclusive. To provide a more robust investigation of this correlation, a meta-analysis was performed. In the present study, a systematic search of PubMed, Embase and CBM databases for studies published prior to June 6, 2012 was performed. The correlation between the CYP1A1 T6235C polymorphism and CAD risk was assessed by calculating pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). Seven studies with a total of 2,903 cases and 2,304 controls were included in the meta-analysis. Overall, the CYP1A1 T6235C polymorphism was not correlated with CAD risk (C vs. T: OR=1.03; 95% CI, 0.87-1.22; P=0.728; CC vs. TT: OR=1.04; 95% CI, 0.84‑1.19; P=0.699; CC+TC vs. TT: OR=1.04; 95% CI, 0.93-1.18; P=0.478; CC vs. TC+TT: OR=1.04; 95% CI, 0.85‑1.28; P=0.704). A meta-analysis of five high-quality studies demonstrated that the CYP1A1 T6235C polymorphism is not correlated with risk of CAD in 4 genetic models. Ethnic subgroup analyses identified no significant correlation in Caucasian, Asian and African populations. The present meta-analysis study indicates that the CYP1A1 T6235C polymorphism is not correlated with CAD risk. Additional studies with a larger sample size and consistent design must be performed to confirm the present hypothesis.

Cytochrome P4501A1 genotypes and smoking- and hypertension-related ischemic stroke risk

This study aimed to determine whether the coding (A4889G) and noncoding region (T6235C) polymorphisms of the gene coding for cytochrome P4501A1 (CYP1A1), a xenobiotic-metabolizing enzyme responsible for the metabolism of carcinogenic polycyclic aromatic hydrocarbons, are involved in the pathogenesis of ischemic stroke in Turkish population. Study group consisted of 226 ischemic stroke patients and 113 controls. Genotypes were attained by allele-specific polymerase chain reaction (PCR) for A4889G and PCR/restriction fragment length polymorphism analysis for T6235C. Frequency of 6235C allele was significantly lower in patients (0.151) compared with controls (0.226, P = 0.015). Prevalence of hypertension and hypertension-associated ischemic stroke risk was lower for 6235C allele carriers. This allele decreased ischemic stroke risk twofold (adjusted odds ratio = 0.48, P = 0.005). There was almost no difference in 4889G allele frequencies in patients (0.445) and controls (0.425). However, prevalence of hypertension was lower in 4889G allele carriers when compared with the wild-type genotypes. In addition, risk of ischemic stroke for smoker and hypertensive individuals was lower when they have at least one 4889G allele. The present study demonstrated that CYP1A1 genetic variants contribute to interindividual variability in smoking- and hypertension-induced ischemic stroke risk.

Polymorphisms of cytochrome p450 genes in three ethnic groups from Russia

OBJECTIVE

To determine the prevalence of the most common allelic variants of CYP1A1, CYP1A2, CYP1B1, CYP2C9, CYP2E1, CYP2F1, CYP2J2 and CYP2S1 in a representative sample of the three ethnic groups (Russians, Tatars and Bashkirs) from Republic of Bashkortostan (Russia), and compare the results with existing data published for other populations.

MATERIAL AND METHODS

CYPs genotypes were determined in 742 DNA samples of healthy unrelated individuals representative of three ethnic groups. The CYPs gene polymorphisms were examined using the PCR-RLFP method.

RESULTS

Analysis of the CYP1A1 (rs1048943, rs4646903), CYP1A2 (rs762551), CYP2E1 (rs2031920) allele, genotype and haplotype frequencies revealed significant differences among healthy residents of the Republic of Bashkortostan of different ethnicities. Distribution of allele and genotype frequencies of CYP1A2 (rs35694136), CYP1B1 (rs1056836), CYP2C9 (rs1799853, rs1057910), CYP2F1 (rs11399890), CYP2J2 (rs890293), CYP2S1 (rs34971233, rs338583) genes were similar in Russians, Tatars, and Bashkirs. Analysis of the CYPs genes allele frequency distribution patterns among the ethnic groups from the Republic of Bashkortostan in comparison with the different populations worldwide was conducted.

CONCLUSION

The peculiarities of the allele frequency distribution of CYPs genes in the ethnic groups of the Republic of Bashkortostan should be taken into consideration in association and pharmacogenetic studies. The results of the present investigation will be of great help in elucidating the genetic background of drug response, susceptibility to cancer and complex diseases, as well as in determining the toxic potentials of environmental pollutants in our region.

Haplotype-based case-control study of CYP4A11 gene and myocardial infarction

CYP4A11, which is a member of the cytochrome P450 family, acts mainly as an enzyme that converts arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE), a metabolite involved in the maintenance of cardiovascular health. Recently, it was reported that many subfamilies of CYP genes have an association with myocardial infarction (MI). The aim of the present study was to assess the association between the human CYP4A11 gene and MI, using a haplotype-based case-control study with a separate analysis of the gender groups. A total of 239 MI patients and 285 controls were genotyped for 3 single-nucleotide polymorphisms (SNPs) of the human CYP4A11 gene (rs2269231, rs1126742, rs9333025). The data obtained via haplotype-based case-control studies were assessed for 3 separate groups: total subjects, men, and women. For the total, men and women groups, the distribution of the genotypes and alleles of the 3 SNPs did not show any significant difference between the MI patients and the control subjects. For the total and the men groups, the overall distribution of the haplotypes constructed with the 3 SNPs significantly differed between the MI patients and control subjects (P < 0.001). Also, for the total and for the men, the frequency of the T-T-A haplotype constructed with the 3 SNPs was significantly lower for the MI patients than for the control subjects (both P < 0.001). The T-T-A haplotype constructed with the 3 SNPs appears to be a protective genetic marker for MI in Japanese men.

Genetic variants in CYP (-1A2, -2C9, -2C19, -3A4 and -3A5), VKORC1 and ABCB1 genes in a black South African population: a window into diversity

AIM

The frequencies of variants of pharmacogenetic importance differ across populations. African populations exhibit the greatest genetic heterogeneity, cautioning against extrapolating results among African groups. The aim of this study was to genotype pharmacogenetically relevant variants in black South Africans, to expand the limited data set available for indigenous African populations.

SUBJECTS & METHODS

A total of 14 SNPs associated with seven genes known to influence drug metabolism or transport (CYP1A2, CYP2C19, CYP2C9, CYP3A4, CYP3A5, VKORC1 and ABCB1) were investigated in a South African black (SAB) population (n = 993) and allele frequencies were compared with populations of African, Asian and European origin.

RESULTS

The majority of SNPs in the SAB demonstrated significant allele frequency differences when compared with both Europeans and Asians. There was greater similarity between the SAB and the Luhya (Kenya) and the Yoruba (Nigeria), than with Maasai (Kenya) individuals. The CYP2C9 SNP (rs1799853) was not polymorphic in the SAB and two VKORC1 SNPs (rs17708472 and rs9934438) had low variant allele frequencies, limiting their relevance to warfarin dose in this population. Population differences are emphasized by the significant differences in ABCB1 and the CYP3A gene family allele frequencies, with implications for drug metabolism and transport.

CONCLUSION

This study highlights the importance of investigating and documenting genetic variation at loci of pharmacogenetic relevance among different populations since this information could be used to inform drug efficacy, safety and recommended dosage.

The influence of a CYP1A2 polymorphism on the ergogenic effects of caffeine

Background

Although caffeine supplementation improves performance, the ergogenic effect is variable. The cause(s) of this variability are unknown. A (C/A) single nucleotide polymorphism at intron 1 of the cytochrome P450 (CYP1A2) gene influences caffeine metabolism and clinical outcomes from caffeine ingestion. The purpose of this study was to determine if this polymorphism influences the ergogenic effect of caffeine supplementation.

Methods

Thirty-five trained male cyclists (age = 25.0 ± 7.3 yrs, height = 178.2 ± 8.8 cm, weight = 74.3 ± 8.8 kg, VO₂max = 59.35 ± 9.72 ml·kg^-1·min^-1) participated in two computer-simulated 40-kilometer time trials on a cycle ergometer. Each test was performed one hour following ingestion of 6 mg·kg^-1 of anhydrous caffeine or a placebo administered in double-blind fashion. DNA was obtained from whole blood samples and genotyped using restriction fragment length polymorphism-polymerase chain reaction. Participants were classified as AA homozygotes (N = 16) or C allele carriers (N = 19). The effects of treatment (caffeine, placebo) and the treatment × genotype interaction were assessed using Repeated Measures Analysis of Variance.

Results

Caffeine supplementation reduced 40 kilometer time by a greater (p < 0.05) magnitude in AA homozygotes (4.9%; caffeine = 72.4 ± 4.2 min, placebo = 76.1 ± 5.8 min) as compared to C allele carriers (1.8%; caffeine = 70.9 ± 4.3 min, placebo = 72.2 ± 4.2 min).

Conclusions

Results suggest that individuals homozygous for the A allele of this polymorphism may have a larger ergogenic effect following caffeine ingestion.

A novel polymorphism of the CYP4A11 gene is associated with coronary artery disease

BACKGROUND

CYP4A11 (cytochrome P450, family 4, subfamily A, polypeptide 11) converts arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE), which plays a crucial role in the modulation of cardiovascular homeostasis. The aim of the present study was to assess the association between the human CYP4A11 gene and coronary artery disease (CAD).

METHODS

A total of 361 patients with CAD and 315 controls were genotyped for 4 single-nucleotide polymorphisms (SNPs) of the human CYP4A11 gene (rs9332978, rs4660980, rs3890011, and rs1126742). The data were assessed for 3 groups: total participants, men, and women via case-control studies.

RESULTS

For total participants and men, the distribution of SNP3 (rs3890011) genotypes showed a significant difference between CAD and control participants (P = .030 and P = .013, respectively), the distribution of the recessive model of SNP3 (GG vs CC + GC) was significantly higher in CAD patients than in control participants (P = .011 and P = .014, respectively), the significant difference was retained after adjustment for covariates (for total participants, 95% confidence interval [CI]: 1.137-2.423, P = .009; and for males, 95% CI: 1.173-3.013, P = .009).

CONCLUSIONS

rs3890011 maybe a novel polymorphism of the CYP4A11 gene associated with CAD in a Han Chinese population.

Genetic determinants of blood pressure responses to caffeine drinking

BACKGROUND

The widely observed between-subject variability in cardiovascular responses to coffee may have a genetic basis.

OBJECTIVE

We evaluated acute blood pressure (BP) responses to caffeine and explored whether they are influenced by candidate gene variants affecting caffeine metabolism (for cytochrome P450 1A2), adenosine metabolism (for adenosine receptor and AMP deaminase), or catecholamine receptors.

METHODS

We recruited 110 healthy male habitual moderate coffee drinkers who refrained from drinking coffee on the day preceding the study. Each subject underwent ambulatory BP monitoring at 6-min intervals for 2 h. Each participant was administered, in a double-blind design, 40 mL of either a decaffeinated coffee preparation plus 3 mg caffeine/kg (caf) or the corresponding vehicle (decaf). The protocol was repeated 24 h later with the alternative preparation. Blood samples were collected for genetic and plasma caffeine and catecholamine evaluations.

RESULTS

Compared with decaf, caf was associated with a mean (± SD) significant increase in systolic BP of 4 ± 12 mm Hg and in diastolic BP of 3 ± 10 mm Hg (P < 0.001 for both). Plasma caffeine and adrenaline increased after caf, but not after decaf. Of 11 gene polymorphisms analyzed, a relation was observed between the ADORA2A TT variant and the change in SBP peak and between the ADRA2B I variant and the changes in both SBP mean and peak; mean peak change in SBP; these variants were associated with increased SBP responses to caf.

CONCLUSIONS

Variability in the acute BP response to coffee may be partly explained by genetic polymorphisms of the adenosine A2A receptors and α(2)-adrenergic receptors. This trial is registered at clinicaltrials.gov as NCT01330680.

Winning a won game: caffeine panacea for obesity syndemic

Over the past decades, chronic sleep reduction and a concurrent development of obesity have been recognized as a common problem in the industrialized world. Among its numerous untoward effects, there is a possibility that insomnia is also a major contributor to obesity. This attribution poses a problem for caffeine, an inexpensive, “natural” agent that is purported to improve a number of conditions and is often indicated in a long-term pharmacotherapy in the context of weight management. The present study used the “common target” approach by exploring the tentative shared molecular networks of insomnia and adiposity. It discusses caffeine targets beyond those associated with adenosine signaling machinery, phosphodiesterases, and calcium release channels. Here, we provide a view suggesting that caffeine could exert some of its effects by acting on several signaling complexes composed of HIF-1α/VEGF/IL-8 along with NO, TNF-α, IL1, and GHRH, among others. Although the relevance of these targets to the reported therapeutic effects of caffeine has remained difficult to assess, the utilization of caffeine efficacies and potencies recommend its repurposing for development of novel therapeutic approaches. Among indications mentioned, are neuroprotective, nootropic, antioxidant, proliferative, anti-fibrotic, and anti-angiogenic that appear under a variety of dissimilar diagnostic labels comorbid with obesity. In the absence of safe and efficacious antiobesity agents, caffeine remains an attractive adjuvant.

Frequencies of genetic polymorphisms related to triptans metabolism in chronic migraine

Chronic migraine (CM) prevalence ranges around 1–5%. Most of these patients usually treat their acute attacks with triptans, whose efficacy is extremely variable. A genetic basis for migraine is evident and many susceptibility genes have been described, as well as gene polymorphisms possibly implied in therapy response. Several factors could be involved in the evolution of episodic migraine into a chronic form, such as natural history, psychiatric comorbidity, and the individual’s response to therapy. During a study aimed at detecting connections between genotype and response to triptans administration, we characterized a CM population for polymorphisms in the genes coding for monoamine oxidase A, g-protein beta 3 and the cytochromes CYP3A4 and CYP1A2. Alleles and genotypes distributions were compared with known frequencies of healthy Caucasian populations. A significant association with CM was found for the long allele of monoamine oxidase A 30 bp VNTR and CYP1A2*1F variant. Such genomic analysis is part of an integrated platform able to evaluate different levels of metabolic pathways of drugs in CM and their influence in the chronicization process.

Effect of cytochrome P450 polymorphism on arachidonic acid metabolism and their impact on cardiovascular diseases

Cardiovascular diseases (CVDs) remain the leading cause of death in the developed countries. Taking into account the mounting evidence about the role of cytochrome P450 (CYP) enzymes in cardiovascular physiology, CYP polymorphisms can be considered one of the major determinants of individual susceptibility to CVDs. One of the important physiological roles of CYP enzymes is the metabolism of arachidonic acid. CYP epoxygenases such as CYP1A2, CYP2C, and CYP2J2 metabolize arachidonic acid to epoxyeicosatrienoic acids (EETs) which generally possess vasodilating, anti-inflammatory, anti-apoptotic, anti-thrombotic, natriuretic, and cardioprotective effects. Therefore, genetic polymorphisms causing lower activity of these enzymes are generally associated with an increased risk of several CVDs such as hypertension and coronary artery disease. EETs are further metabolized by soluble epoxide hydrolase (sEH) to the less biologically active dihydroxyeicosatrienoic acids (DHETs). Therefore, sEH polymorphism has also been shown to affect arachidonic acid metabolism and to be associated with CVDs. On the other hand, CYP omega-hydroxylases such as CYP4A11 and CYP4F2 metabolize arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE) which has both vasoconstricting and natriuretic effects. Genetic polymorphisms causing lower activity of these enzymes are generally associated with higher risk of hypertension. Nevertheless, some studies have denied the association between polymorphisms in the arachidonic acid pathway and CVDs. Therefore, more research is needed to confirm this association and to better understand the pathophysiologic mechanisms behind it.

Genetic variants in microsomal epoxide hydrolase influence carbamazepine dosing

OBJECTIVES

The dose of carbamazepine required to achieve optimal seizure control varies widely from patient to patient. We investigated polymorphic variants in various genes involved in the pharmacokinetics and pharmacodynamics of carbamazepine in an effort to identify predictors of maintenance dose.

METHODS

: A total of 70 patients with epilepsy (49% were males; median age, 34 years; range, 14-72 years) who had benefited (>50% reduction in seizure frequency for at least 12 months) from treatment with carbamazepine monotherapy were included in the analysis. Known variants in drug-metabolizing enzyme genes, including those encoding cytochrome P450s, uridine 5'-diphosphate-glycosyltransferase, and microsomal epoxide hydrolase, together with a sodium channel polymorphism in SCN2A, were screened using polymerase chain reaction-restriction fragment length polymorphism or direct sequencing. Associations between demographic and genetic variables and carbamazepine dose were identified by univariate and multivariate regression analyses.

RESULTS

All genotype frequencies were consistent with Hardy-Weinberg equilibrium (P > 0.05). No single demographic or genetic variable was of sufficient strength to independently influence carbamazepine dosing requirements. However, a multivariate model, incorporating patient age and specific genotypes (c.337T>C, c.416A>G) of the EPHX1 gene encoding microsomal epoxide hydrolase, revealed a significant association with the maintenance dose of carbamazepine (r(2) = 0.362, P= 0.002).

CONCLUSIONS

This proof-of-principle study suggests that genetic variants in EPHX1 can be used to predict maintenance doses of carbamazepine. A large-scale prospective investigation of genetic influences on drug dosing strategies in epilepsy, with specific focus on whole gene variability for those proteins involved in the pharmacokinetics and pharmacodynamics of antiepileptic agents, is warranted.

CYP1A2 genotype and rheumatoid arthritis in Koreans

Cytochrome P540 (CYP) 1A2 plays a role in the production of reactive oxygen species (ROS), which have been implicated in the development of rheumatoid arthritis (RA). The objective of this study was to investigate the association between a common polymorphism in the CYP1A2 gene with risk and severity of RA in a Korean population. Cases (n = 1321) with RA and controls (n = 1037) were genotyped for the CYP1A2 -163 A>C polymorphism by real-time PCR. HLA-DRB1 typing and further subtyping of all alleles was performed by PCR, sequence-specific oligonucleotide probe hybridization and direct DNA sequencing analysis. The odds ratio (OR) [(95% confidence interval (CI)] of RA associated with the low inducible C allele was 1.11 (0.80-1.55) among non-shared epitope (SE) carriers, 0.82 (0.56-1.20) among heterozygotes and 0.32 (0.10-1.04) among individuals homozygous for the SE (P = 0.03 for CYP1A2-SE interaction). A protective effect of the low inducibility CYP1A2 C allele among carriers of the SE suggests that a product of CYP1A2-mediated metabolism, such as ROS, may be involved in the development of RA.

A haplotype of the CYP4F2 gene associated with myocardial infarction in Japanese men

This study assessed associations between the CYP4F2 gene and myocardial infarction (MI), using a haplotype-based case-control study of 234 MI patients and 248 controls genotyped for 5 single-nucleotide polymorphisms (rs3093105, rs3093135, rs1558139, rs2108622, rs3093200). For men, G allele frequency of rs2108622 and frequency of the T-C-G haplotype were significantly higher, and frequency of the T-C-A haplotype was significantly lower for MI patients than for controls (P=0.006, P=0.001 and P=0.002, respectively).

GSTM1, GSTT1 and CYP1A1 detoxification gene polymorphisms and susceptibility to smoking-related coronary artery disease: a case-only study

Cigarette smoking is a powerful risk factor for coronary artery disease (CAD), leading to the formation of DNA alterations within blood vessels and heart. However, the degree of smoking-related atherosclerosis varies from individual to individual. Genetic polymorphisms of relevant xenobiotic metabolising enzymes may determine the susceptibility of an individual response to environmental toxicants. The purpose of this study was to test the hypothesis that the inheritance of polymorphic genes encoding cytochrome P450 1A1 (CYP1A1 MspI) and glutathione S-transferases (GSTM1(null) and GSTT1(null)) may be causally associated with the presence and severity of smoking-induced CAD. In a case-only design, 222 (179 male, 57.8+/-10.3 years) consecutive smoker patients who had undergone elective and diagnostic coronary angiography were recruited. We found a group (n=169) of smoker patients with significant CAD, defined as>50% reduction in diameter of at least one major vessel, and a group without obstructive CAD (n=53). No significant differences were observed in CYP1A1 genotypes frequencies between CAD and non-CAD smokers (p=0.1). Homozygous deletion of GSTM1 had a frequency of 58.6% among patients with CAD and 45.3% among those without CAD (p=0.08). The frequency of the GSTT1(null) genotype was 43.8% among the patients with CAD and 24.5% among CAD-free subjects (p=0.01). After adjustment for traditional risk factors, the presence of combined GSTM1(null)GSTT1(null) genotypes was significantly associated with an increased risk of CAD (OR=3.9; 95% CI: 1.3-11.4, p=0.01). Moreover, smokers with combined GSTM1(null)GSTT1(null) genotypes had significantly higher number of stenosed vessels than those with the positive genotype (2.3+/-0.9 versus 1.7+/-0.8, p=0.03). Our findings showed that smokers carrying GST deleted genotypes have an increased susceptibility to the smoking related coronary artery disease. Exploring gene-smoking effect provides an excellent model in order to understand gene-environment toxicants interaction and its implications to cardiovascular disease.