Polimorfismos em genes envolvidos na farmacodinâmica de tacrolimo e everolimo e sua relação com a resposta ao tratamento imunossupressor, em receptores de transplante renal / Polymorphisms in pharmacodynamics-related genes of tacrolimus and everolimus and their relationship with the response to immunosuppressant treatment, in kidney transplant recipients

O monitoramento de imunossupressores, como os inibidores de calcineurina ou de mTOR, é essencial para evitar desfechos clínicos desfavoráveis, em receptores de transplante renal. Polimorfismos em genes envolvidos na farmacocinética têm sido associados com variabilidade na resposta a imunossupressores, porém o papel de polimorfismos em genes envolvidos na farmacodinâmica é pouco conhecido. O objetivo deste estudo foi investigar a influência de polimorfismos de MTOR, PPP3CA, FKBP1A, FKBP2 e FOXP3, genes envolvidos na farmacodinâmica de imunossupressores, sobre a resposta clínica a tacrolimo e everolimo, em receptores de transplante renal. Foram incluídos 269 pacientes do ensaio clínico original (NCT01354301), realizado no Hospital do Rim e Hipertensão da UNIFESP, e randomizados em três esquemas imunossupressores: tacrolimo 0,05 mg/kg/dia com everolimo 1,5 mg/dia (TAC5/EVR); tacrolimo 0,1 mg/kg/dia com everolimo 1,5 mg/dia (TAC10/EVR); e tacrolimo 0,1 mg/kg/dia com micofenolato de sódio (TAC10/MFS). Foram coletados dados clínicos e laboratoriais, tais como o monitoramento de imunossupressores e desfechos de eficácia de segurança. Os polimorfismos nos genes MTOR (c.4731G>A, c.1437T>C, c.2997C>T); PPP3CA (c.249G>A); FKBP1A (n.259+243936T>C); FBKP2 (c.-2110G>T) e FOXP3 (c.-23+2882A>C, c.-22-902A>G) foram analisados por PCR em tempo real. As frequências alélicas dos polimorfismos estudados foram similares às da população global do projeto 1000genomes. O tratamento com everolimo e tacrolimo em maior dose (TAC10/EVR) foi associado com menor taxa de filtração glomerular estimada (TFGe) e maior creatinina sérica. Enquanto que o tratamento com tacrolimo e micofenolato de sódio (TAC10/MFS) foi associado com maior número de episódios de infecção por citomegalovirus, no 1° ano pós-transplante. Com relação aos desfechos de eficácia, os portadores do genótipo CC de MTOR c.1437T>C e FOXP3 c-23+2882A>C apresentaram maiores concentrações de creatinina sérica, no 12° mês (p<0,05). O polimorfismo FOXP3 c.-23+2882A>C foi associado com maior probabilidade de creatinina sérica aumentada (OR=1,75; IC95%=1,07-2,86; p=0,025). Os resultados da análise de regressão logística mostraram que o alelo MTOR c.4731G (genótipos AG+GG) foi associado com maior risco de rejeição aguda (OR=3,37; IC95%=1,10-10,30; p=0,033). Os portadores do alelo c.4731G apresentaram maior incidência cumulativa de episódios de rejeição, no 1° ano pós-transplante. Com relação aos desfechos de segurança, a variante FKBP2 c.-2110G>T (genótipo GG) foi associada com maior risco de leucopenia (OR=7,10; IC95%=1,81-27,87; p=0,025). O polimorfismo FKBP1A n.259+24936T>C (alelo C) foi associado com maior risco de constipação (OR=2,52; IC95%=1,13 - 5,61; p=0,024), enquanto que os polimorfismos FOXP3 c.-22-902A>G (alelo A) e c.-23+2882A>C (alelo A) foram associados, respectivamente, com maior risco de epigastralgia (OR=2,15; IC95%=1,01-4,56; p=0,047) e náuseas e/ou vômitos (OR=2,38; IC95%=1,05-5,38; p=0,038). O risco de apresentar dislipidemia foi maior nos portadores dos genótipos FKBP2 c.-21110GG (OR=1,92; IC95%=1,01-3,69; p=0,049) e FOXP3 c.-22-902GG (OR=2,06; IC95%=1,08-3,92; p=0,028). Em conclusão, os polimorfismos de genes MTOR, FKBP1A, FKBP2 e FOXP3 influenciam na função renal do enxerto e estão associados com risco de rejeição aguda e de eventos adversos, em receptores de transplante renal

The monitoring of immunosuppressive drugs, such as calcineurin and mTOR inhibitors, is essential to avoid undesirable kidney transplant outcomes. Polymorphisms in pharmacokinetics-related genes have been associated with variability in the response to immunosuppressive drugs, but the role of polymorphisms in pharmacodynamics-related genes is little known. The aim of this work was to investigate the influence of polymorphisms in MTOR, PPP3CA, FKBP1A, FKBP2 and FOXP3, genes involved in the pharmacodynamics of immunosuppressive drugs, on the clinical response to tacrolimus and everolimus in kidney transplant recipients. Two-hundred seventy-five kidney transplant recipients were included in this study, among the enrolled in the original clinical trial (NCT01354301) carried out at the Hospital do Rim e Hipertensão/UNIFESP, and randomized in three immunosuppressive treatments: tacrolimus 0.05 mg/kg/day with everolimus 1.5 mg/day (TAC5/EVR); tacrolimus 0.1 mg/kg/day with everolimus 1.5 mg/day (TAC10/EVR); and tacrolimus 0.1 mg/kg/day with sodium mycophenolate (TAC10/MFS). Clinical and laboratory data, including immunosuppressive drug monitoring, efficacy and safety outcomes, were recorded. Polymorphisms on the MTOR (c.4731G>A, c.1437T>C, c.2997C>T); PPP3CA (c.249G>A); FKBP1A (n.259+243936T>C); FBKP2 (c.-2110G>T) and FOXP3 (c.-23+2882A>C, c.-22-902A>G) genes were analyzed by real-time PCR. Allelic frequencies of the studied polymorphisms were similar to those of the global population reported by the 1000genomes project. Treatment with everolimus and high-dose tacrolimus (TAC10/EVR) was associated with lower estimated glomerular filtration rate (eGFR) and higher serum creatinine. Meanwhile treatment with tacrolimus and sodium mycophenolate (TAC10/MFS) was associated with higher number of cytomegalovirus infections, at 1-year post-transplantation. With regard to the kidney efficacy outcomes, the carriers of the CC genotype of MTOR c.1437T>C and FOXP3 c.-23+2882A>C had higher serum creatinine, at month 12 (p<0.05). The FOXP3 c.-23+2882A>C polymorphism was associated with high likelihood of increased serum creatinine (OR=1.75, 95%IC=1.07-2.86, p=0.025). The results of the logistic regression analysis showed that the allele MTOR c.4731G (AG+GG genotypes) was associated with higher risk of acute rejection (OR=3.37, 95%IC=1.10-10.30, p=0.033). The carriers of the c.4731G allele showed higher cumulative incidence of acute rejection episodes at 1-year post-transplantation. With regard to kidney safety outcomes, the FKBP2 c.-2110G>T variant (GG genotype) was associated with higher risk of leucopenia (OR=7.10, 95%IC=1.81-27.87, p=0.025). The FKBP1A n.259+24936T>C (C allele) polymorphism was associated with higher risk of constipation (OR=2.52, 95%IC=1.13-5.61, p=0.024), whilst FOXP3 c.-22 902A>G (A allele) and c.-23+2882A>C (A allele) were associated, respectively, with higher risk of epigastric pain (OR=2.15, 95%IC=1.01-4.56, p=0.047) and nausea and/or vomiting (OR=2.38, 95%IC=1.05-5.38, p=0.038). The risk of developing dyslipidemia was higher in carriers of the genotypes FKBP2 c.-21110GG (OR=1.92, 95%CI=1.01-3.69, p=0.049) and FOXP3 c.-22-902GG (OR=2.06, 95%CI=1.08-3.92, p=0.028). In conclusion, the polymorphisms in the MTOR, FKBP1A, FKBP2 and FOXP3 genes influence renal graft function and are associated with risk of acute rejection and adverse events in renal transplant recipients

Efeito da pioglitazona sobre o remodelamento ósseo em diabetes tipo 2 / Pioglitazone effect on bone remodeling in type 2 diabetes

Alterações morfológicas no tecido ósseo têm sido descritas nos usuários de hipoglicemiantes orais da classe das tiazolidinedionas (TZDs). Hipotetiza-se que alguns genes relacionados com a osteogênese e osteoclastogênese podem ser influenciados pelo tratamento farmacológico, entretanto, o exato mecanismo ainda não está bem esclarecido. O objetivo do estudo foi avaliar o efeito da pioglitazona no remodelamento ósseo através de genes envolvidos na osteoclastogênese em indivíduos recentemente diagnosticados com DM2 e modelos animais, com a finalidade de identificar marcadores genéticos sensíveis de alterações ósseas. Foram convidados para participar do estudo 199 indivíduos (100 diabéticos e 99 normoglicêmicos), no ambulatório de dislipidemias do Instituto Dante Pazzanese de Cardiologia. Os indivíduos diabéticos foram tratados com pioglitazona (15, 30, 45, 45 mg/ dia/ via oral) por 16 semanas. Foram colhidas amostras de sangue, antes e após o tratamento para avaliações laboratoriais, extração de DNA genômico e de RNA total. Os polimorfismos e a expressão do mRNA nas células sanguíneas foram determinados pela PCR em tempo real através do sistema TaqMan®. Para o estudo em modelo animal após a indução da dieta hiperlipídica por 32 semanas, foram utilizados 12 camundongos machos da linhagem C57BL/J6, os quais foram divididos em três grupos: controle (n=4); diabéticos induzidos pela dieta hiperlipídica (DH, n=4) e diabéticos induzidos pela dieta hiperlipídica e tratados com pioglitazona 35mg/Kg/dia por 16 semanas (DHP, n=4). Para os grupos experimentais foram colhidos: amostras de sangue, para exames laboratoriais; fêmures, para a extração do RNA total; e tíbias, para determinação dos parâmetros histomorfométricos. Os pacientes DM2 apresentaram diminuição nas concentrações séricas de osteocalcina e na expressão de OPG e aumento na expressão de VDR em comparação ao grupo NG (p<0,05). A expressão de RANKL e IL6 foi maior entre as mulheres, enquanto que a expressão de PPARG foi maior entre os homens com DM2 em comparação ao grupo NG (p=0,032). Pacientes DM2 antes do tratamento apresentaram glicemia e expressão do mRNA de IL6 negativamente associados ao cálcio ionizado, enquanto que as transcrições de TNFA e VDR foram associadas positivamente e negativamente com bALP respectivamente (p<0,05). O tratamento com pioglitazona reduziu a glicemia de jejum, glicemia pós-prandial, insulina, HOMA-IR, triglicerídeos, VLDL-C, tALP e bALP e aumentou a HDL, tACP, TNF-α e a transcrição de OPG (p<0,05). A glicemia basal associou-se positivamente com o cálcio ionizado. A expressão basal de OPG foi associado negativamente com tALP, enquanto que a expressão basal de TNFA foi associada positivamente com tALP e negativamente com tACP. A expressão basal IL6 foi associada positivamente com tALP, enquanto que a expressão basal de VDR foi associada negativamente com osteocalcina e positivamente com bALP em resposta ao tratamento (p<0,05). O polimorfismo RANK rs1805034 foi associado com redução na transcrição do gene RANK nos indivíduos DM2 e com o remodelamento ósseo após o tratamento com pioglitazona (p<0,05). O polimorfismo RANKL rs9525641 foi associado com aumento da transcrição gênica de RANKL nos indivíduos NG e DM2 e melhora da resposta farmacológica nos indivíduos DM2 tratados com pioglitazona (p<0,05). O polimorfismo rs3102735 do gene OPG foi associado com aumento da formação óssea nos indivíduos DM2 antes e após o tratamento (p<0,05). O genótipo CG do polimorfismo OPG rs2073618 foi associado com alteração da transcrição de OPG no grupo DM2 pré e pós-tratamento (p<0,05). O polimorfismo PPARG rs1801282 foi associado com menor risco para o desenvolvimento de diabetes (p<0,05). O polimorfismo PPARG rs2972162 foi associado com melhora da resistência insulínica nos indivíduos DM2 tratados com pioglitazona (p=0,017). O polimorfismo ESRI rs9340799 foi associado com redução da formação óssea nos indivíduos DM2 (p=0,038). Nos camundongos, após a indução da dieta hiperlipídica por 32 semanas, observou-se aumento do peso, da glicemia, do colesterol total, da expressão do mRNA de RANK, RANKL, IL6 e TNFA em fêmures e aumento de Tb.Sp e diminuição de BV/TV em comparação ao grupo controle (p<0,05). O tratamento com pioglitazona diminuiu a expressão de TNFA (p=0,028). As medidas histomorfométricas não alteraram-se após o tratamento (p>0,05). Os resultados sugerem que o estado hiperglicêmico e o tratamento influenciam os marcadores bioquímicos e moleculares. Os polimorfismos dos genes RANK, RANKL, OPG e ESRI parecem estar envolvidos no remodelamento ósseo independentemente da hiperglicemia e do tratamento e os polimorfismos do gene PPARG parecem estar envolvidos com menor risco para desenvolver diabetes e com a melhora da resistência insulínica em resposta ao tratamento com pioglitazona

Morphological changes in bone tissue have been reported in users of oral hypoglycemic class of thiazolidinediones (TZDs). It is hypothesized that some genes related to osteogenesis and osteoclastogenesis may be influenced by pharmacological treatment, however, was not aware exact mechanism. The study aims was to evaluate pioglitazone effect on bone remodeling through genes involved in osteoclastogenesis in individuals newly diagnosed with DM2 and animal models, in order to identify sensibles genetics markers of bone alterations. Were invited to participate in study 199 patients (100 diabetics and 99 normoglycemic), in dyslipidemia ambulatory of Institute Dante Pazzanese of Cardiology. Diabetic subjects were treated with pioglitazone (15, 30, 45 or 45 mg /day/oral) for 16 weeks. Blood samples were collected before and after treatment for laboratory evaluations, extraction of genomic DNA and total RNA. Polymorphisms and mRNA expression in blood cells was determined by real time PCR using TaqMan® system. For study in animal model after 32 weeks of fat diet induction, was used 12 male mice C57BL/J6, which were divided into three groups: control (n=4); induced diabetic fat diet (DH, n=4) and induced diabetic fat diet and treated with pioglitazone 35mg/Kg/day for 16 weeks (DHP, n=4). For experimental groups were collected: blood samples for laboratory tests; femurs, for extraction of total RNA; and tibias, to determine histomorphometric parameters. DM2 patients showed decrease in serum osteocalcin and OPG expression and increased VDR expression compared to NG group (p<0.05). RANKL and IL6 expression were higher among women, whereas PPARG expression was higher among men with DM2 compared to NG group (p=0,032). DM2 patients before treatment showed blood glucose and IL6 mRNA expression negatively associated with ionized calcium, whereas TNFA and VDR transcription are positively and negatively associated with bALP respectively (p<0.05). Pioglitazone treatment reduced fasting glucose, postprandial glucose, insulin, HOMA-IR, triglycerides, VLDL-C, tALP and bALP and increased HDL, tACP, TNF-α and OPG transcription (p<0.05). Basal blood glucose was positively associated with ionized calcium. Basal OPG expression was negatively associated with tALP, whereas basal TNFA expression was positively associated with tALP and negatively with tACP. Basal IL6 expression was positively associated with tALP, whereas basal VDR expression was negatively associated with osteocalcin and positively with bALP in response to treatment (p<0.05). RANK rs1805034 polymorphism was associated with RANK gene transcription reduction in subjects with DM2 and bone remodeling after treatment with pioglitazone (p<0.05). RANKL rs9525641 polymorphism was associated with increased RANKL gene transcription in NG and DM2 subjects and pharmacological response improvement in DM2 subjects treated with pioglitazone (p<0.05). OPG rs3102735polymorphism was associated with increased bone formation in DM2 subjects before and after treatment (p<0.05). CG genotype of OPG rs2073618 polymorphism was associated with OPG transcription change in DM2 group before and after treatment (p<0.05). PPARG rs1801282 polymorphism was associated with lower risk for diabetes development (p<0.05). PPARG rs2972162 polymorphism was associated with insulin resistance improvement in DM2 subjects treated with pioglitazone (p=0,017). ESRI rs9340799 polymorphism was associated with reduced bone formation in DM2 subjects (p=0,038). In mice, after 32 weeks of fat diet induction, was observed increase weight, blood glucose, total cholesterol and RANK, RANKL, IL6 and TNFA mRNA expression in femurs and Tb.Sp increase and BV/TV decrease compared to control group (p<0.05). Treatment with pioglitazone decrease TNFA (p=0,028). Histomorphometrics measurements not change after treatment (p>0.05). Results suggest that hyperglycemic state and treatment influence biochemical and molecular markers. RANK, RANKL, OPG and ESRI polymorphisms seens to be involved in bone remodeling regardless of hyperglycemia and treatment and PPARG gene polymorphisms seens to be associated with lower risk for diabetes development and with insulin resistance improvement in response to treatment with pioglitazone

The Role of Pharmacoethnicity in the Development of Cytotoxic and Molecular Targeted Drugs in Oncology

The effective and toxic ranges of anticancer drugs are very narrow and, in some cases, inverted. Thus determination of the most appropriate dosage and schedule of administration is crucial for optimal chemotherapy. In common arm trials conducted in Japan and by Southwest Oncology Group (SWOG) that used the same doses and schedules for the administration of carboplatin plus paclitaxel, the frequency of hematological toxicity was significantly higher in the Japanese trials than in the SWOG trial, despite demonstrating similar response rates. The frequency of epidermal growth factor receptor (EGFR) mutations in tumors was significantly higher among East Asian populations, and these populations are also reported to demonstrate a higher response rates to epidermal growth factor receptor tyrosine-kinase inhibitors (EGFR-TKIs). The prevalence of interstitial lung disease induced by treatment with EGFR-TKIs has been shown to be quite high in the Japanese population. Clinical trials of cetuximab against non-small cell lung cancer and of bevacizumab against stomach cancer have shown that these agents are only active in Caucasians. In a trial examining the use of sorafenib after transarterial chemoembolization in Korean and Japanese patients with advanced hepatocellular carcinoma, the compliance and dose intensity of the drug were quite low compared with other trials. Although not only identified pharmacogenomics differences but also differences in social environment, and regional medical care, including pharmacoeconomics strongly influence ethnic differences in treatment response, further identification and understanding of the pharmacogenomics underlying ethnic differences will be essential to timely and reliable global development of new anticancer drugs.

Pharmacogenetic Influence of LOC387715/HTRA1 on the Efficacy of Bevacizumab Treatment for Age-Related Macular Degeneration in a Korean Population

PURPOSE: The purpose of this study was to determine the pharmacogenetic effects of complement factor H (CFH) Y402H, LOC387715 and high-temperature requirement factor A1 (HTRA1) genotypes on the treatment of exudative age-related macular degeneration (AMD) by intravitreal bevacizumab injection in a Korean population. METHODS: Seventy-five patients diagnosed with exudative AMD were treated with intravitreal bevacizumab (2.5 mg) monotherapy. All patients received three initial intravitreal bevacizumab injections every four weeks and were then treated "as needed" based on clinical findings, optical coherence tomography and fluorescein angiography during the 12 month follow-up period after the third injection. RESULTS: The difference in visual acuity improvement among the three genotypes of LOC387715 were statistically significant at six months post-treatment (logarithm of the minimum angle of resolution; TT, 0.346; GT, 0.264; GG, 0.188; p = 0.037). Among the LOC387715 genotypes, the number of additional injections was lower in patients who had the risk T allele (GG, 2.143; GT, 2.000; TT, 1.575; p = 0.064). There was no significant difference between visual acuity and central macular thickness change in the CFH Y402H polymorphism group during the 12 month follow-up period. However, the TC group of CFH Y402H required more additional bevacizumab injections than the TT group (TT, 1.517; TC, 3.363; p = 0.020). CONCLUSIONS: This study demonstrated that different LOC387715/HTRA1 genotypes resulted in different bevacizumab treatment responses on exudative AMD. Patients with the risk allele had an improved treatment response and less need for additional injections. However, patients with the CFH Y402H risk allele needed more additional injections of bevacizumab in order to improve visual acuity. This study illustrates how pharmacogenetic factors may help determine treatment modality and dosing. This could ultimately provide basic data for 'personalized medicine' in AMD.

Farmacogenética aplicada al tratamiento de la leucemia linfoide aguda / Pharmacogenetics applied to the treatment of acute lymphoid leukemia

Las enzimas de biotransformación y eliminación de los fármacos en pacientes con leucemia linfoide aguda tienen una acción determinante en el efecto terapéutico de los medicamentos antineoplßsicos. La presencia y actividad de estos complejos enzimáticos está codificada genéticamente y sujeta a variaciones alélicas, cuyas frecuencias son variables en las diferentes poblaciones humanas. Este polimorfismo genético influye sobre la efectividad terapéutica de los medicamentos y condiciona la carencia de toxicidad o presencia de esta, que en ocasiones puede ser fatal. Las enzimas tiopurin-metil-transferasa, metilén-tetrahidrofolato-reductasa y glutatión-tranferasa son sistemas destoxificadores de algunos de los quimioterápicos empleados en el tratamiento de la leucemia linfoide aguda. En este trabajo se revisan las características genéticas de estas enzimas, la frecuencia de sus polimorfismos y las implicaciones clínicas de su expresión. De igual modo se discute la importancia y los beneficios del genotipaje previo al inicio del tratamiento, con el fin de modificar las dosis de los medicamentos para optimizar su efecto terapéutico y disminuir su toxicidad. La farmacogenética constituye un área de creciente interés que ha tenido un desarrollo considerable en los últimos años, su conocimiento e implementación nos colocará en el camino de la medicina personalizada

The biotransformation and elimination enzymes of drugs in patients suffering from acute lymphoid leukemia play a decisive role on the therapeutical effect of anti-neoplastic drugs. The presence and activity of these enzymatic complexes are genetically coded and subjected to allele variations, the frequency of which is variable in the different human populations. This genetic polymorphism has an impact on the therapeutic effectiveness of drugs and determines the lack or the existence of toxicity that may sometimes become lethal. The enzymes called thiopurine-methyltransferase, methylen-tetrahydropholate-reductase and glutathione-transferase are detoxifying systems of some of the chemotherapeutic drugs that are used for the treatment of acute lymphoid leukemia. This paper reviewed the genetic characteristics of the enzymes, the frequency of polymorphisms and the clinical implications of their expression. Similarly, the importance and the benefits of genotyping before the treatment were discussed in order to change the drug doses to maximize the therapeutic effect and reduce toxicity. Pharmacogenetics has experienced great development in the last few years and draws growing interest; the knowledge about and the implementation of this discipline will take us to the customized medicine

Prevalence of endothelial nitric oxide synthase (eNOS) gene exon 7 Glu298Asp variant in North Eastern India.

Background & objectives Endothelial nitric oxide is a potent vasodilator and impairment of its generation brought about by gene polymorphism is considered a major predictor for several diseases. A single nucleotide polymorphism G894T within exon 7 of endothelial nitric oxide synthase (eNOS-7) gene, resulting in a replacement of glutamic acid by aspartic acid, has been studied as a putative candidate gene for cardiovascular diseases. The pattern of eNOS-7 Glu298Asp variant in the Indian population is poorly known. The present study was planned to determine the prevalence of the variant of this gene among tea garden community in Assam, North-East India with high prevalence of hypertension. Methods Study participants of both sex aged ≥18 yr were recruited randomly from temporary field clinics established in tea gardens of Dibrugarh, Assam. Genomic DNA was extracted from 409 subjects by the conventional phenol-chloroform method. The prevalence of the eNOS exon 7 Glu298Asp variant was determined by polymerase chain reaction and restriction fragment length polymorphism analysis. Results The study population was in Hardy-Weinberg Equilibrium. The frequency of the eNOS GG, GT and TT genotypes was found to be 75, 22 and 3 per cent respectively and did not show any significant difference in gender wise analysis. Interpretation & conclusions Our results showed that the prevalence of the homozygous GG genotype was high (75%) and the rare mutant genotype (homozygous, TT) was 3 per cent in a population at risk with cardiovascular disease. Such population-based data on various polymorphisms can ultimately be exploited in pharmacogenomics.

Human immunodeficiency virus therapeutics and pharmacogenomics.

Pharmacogenomics and pharmacogenetics are promising in development of a personalized treatment approach They are of paramount importance for basic immunology, for peptide based vaccine design (vaccinomics) drug monitoring in clinical setting and molecular pathophysiology of multifactorial diseases like cancer, tuberculosis, cardiac disorders, diabetes, asthma, HIV, etc

Challenges and recommendations for conducting epidemiological studies in the field of epilepsy pharmacogenetics.

Epilepsy is one of the most prevalent neurological disorders, afflicting approximately 50 million Indians. Owing to affordability and easy availability, use of first-generation antiepileptic drugs (AEDs) is heavily encouraged for the treatment of epilepsy in resource-limited countries such as India. Although first-generation AEDs are at par with second-generation AEDs in terms of efficacy, adverse drug reactions (ADRs) are quite common with them. This could be attributed to the inferior pharmacokinetic parameters such as nonlinear metabolism, narrow therapeutic index and formation of toxic intermediates. In addition, epilepsy patients may differ in the pharmacokinetic and pharmacodynamic profiles, with about 1/3rd of the population failing to respond to treatment. A proportion of this interindividual variability in response may be explained by genetic heterogeneity in the activity and expression of the network of proteins such as metabolizing enzymes, transporters and targets of AEDs. Over the last two decades, a considerable effort has been made by the scientific community for unraveling this genetic basis of variable response to AEDs. However, there have been inconsistencies in such genetic association studies conducted across different territories of the world. There could be several reasons underlying the poor replicability of these studies, mainly nonuniform phenotypic definitions, poor sample size and interethnic variability. In the present review article, we provide an overview of heterogeneity in study designs for conducting pharmacogenetic studies. In addition, critical recommendations required for overcoming such challenges imposed by pharmacogenetic epidemiological studies have been briefly discussed.

Drugs impact on CYP-450 enzyme family: A pharmacogenetical study of response variation.

Pharmacogenetics is the study of genetic basis in the individual response to drugs. A thorough knowledge of this will lead to a future where tailor-made drugs, suiting an individual, can be used. Scandinavian countries have been known for wide usage of pharmacogenetics and the most widely used application is for genotyping CYP2D6 in treating psychiatric illness. The CYP-450 enzyme, a super family of microsomal drug-metabolizing enzymes, is the most important of enzymes that catalyzes phase-I drug metabolism reaction. CYP2D6 is a member of this family and it has been most intensively studied and the best example of pharmacogenetics variation in drug metabolism. Neuro-transmitter and drug acting CNS viz. codeine, dextromethorphan, metoprolol and tryptyline etc. are well metabolized by this enzyme. Thus, CYP2D6 is one of the most important and responsible enzymes which regulates bioavailability and metabolism of drug. Presently 75 alleles of CYP2D6 have been described which are responsible for variance of metabolism and toxicity of drugs. Thus, by determining variance of CYP2D6 using molecular approaches viz., PCR, real-time PCR, DNA micro-array and molecular docking can determine the adverse effects, drug toxicity, bioavailability and therapeutic potential of new drug.

Efeitos de hipolipemiantes e polimorfismos sobre a expressão dos genes HMGCR, LDLR, SREBF1a, SREBF2, SCAP e NPC1L1 em indivíduos hipercolesterolêmicos / Lipid lowering and polymorphisms effects on the expression of HMGCR, LDLR, SREBF1a, SREBF2, SCAP and NPC1L1 genes in hypercholesterolemic subjects

A homeostase do colesterol é mediada por proteínas envolvidas na absorçao (NPC1L1), regulação (SREBP1, SREBP2, SCAP), síntese (HMGCR) e remoção plasmática (LDLR). Os fármacos inibidores da síntese (vastatinas) e absorção (ezetimiba) do colesterol são potentes agentes hipocolesterolemiantes. Alteracões em vários genes têm sido associadas a diferenças na resposta a diversos agentes terapêuticos. Com a finalidade de estudar os efeitos de hipolipemiantes e polimorfismos sobre a expressão dos genes HMGCR, LDLR, SREBF1a, SREBF2, SCAP e NPC1L1, foram selecionados 25 indivíduos com hipercolesterolemia familial (HF), 72 com hipercolesterolemia não familial (HNF) e 125 indivíduos normolipidêmicos e sem doença cardiovascular (NL). Os indivíduos HF foram tratados com sinvastatina (40 mg/dia/4 sem) combinada ou não com ezetimiba (10 mg/dia/4sem) e os HNF foram tratados com atorvastatina (10 mg/dia/4sem). Amostras de sangue foram obtidas antes e após o tratamento para a extração de DNA e RNA e analise do perfil lipídico sérico. A expressão de mRNA dos genes SREBF1a, SREBF2, SCAP, HMGCR, LDLR e NPC1L1 em células mononucleares do sangue periférico (CMSP) foi determinada por RT-PCR em tempo real empregando-se o gene da GAPD como controle endógeno...

Human genetic variation and personalized medicine.

Human genome sequencing results revealed an insight into the role of human genetic variation behind differential susceptibility of human diseases, differential response to pharmacological agents and presence of varied phenotypes. This leads to the concept of personalized medicine. In the present review we have discussed the objectives and approaches for carrying out pharmacogenomics and pharmacogenetics studies. The review also incorporates the major findings categorizing the common diseases on the basis of genetic profiles and ethnic information and in establishing personalized disease diagnosis, drug responses and treatment modalities based on the genetic determinants. Overall an attempt has been made to highlight the importance of studying the genetic profiles of an individual in biomedical and pharmacogenomics research.

Farmacogenética em cardiologia / Pharmacogenetics in cardiology

Vários fatores influenciam as respostas às drogas utilizadas em Cardiologia. Embora a interação de vários fatores torne difícil prever a resposta a drogas, o progresso científico das últimas duas décadas criou a expectativa de que se possa determinar como variações genéticas(polimorfismos) afetam as respostas às drogas. Nesta revisão, objetivamos proporcionar ao cardiologista clínico uma introdução a alguns dos principais conceitos relativos à Farmacogenética, bem como uma breve perspectiva clínica de alguns dos principais avanços recentes realiaados pela Farmacogenética na terapêutica cardiovascular. Muitas conquistas já foram feitas em estudos Farmacogenéticos relacionados a aspectos farmacocinéticos. Atualmente vários estudos enfocam aspectos Farmacogenéticos da farmacodinâmica cardiovascular. Exemplos de polimorfismos que afetam a farmacocinética das drogas utilizadas em Cardiologia incluem polimorfismos de enzimas do citocromo P450. Em particular, polimorfismos da CYP 2C9 afetam as respostas ao wafarin e aos antagonistas de receptores do tipo 1 da angiotensina II. Polimorfismos da CYP 2D6 afetam o metabolismo de vários betabloqueadores e de antiarrítmicos. Polimosfismos da CYP 3A4 afetam o metabolismo de várias estatinas e de bloqueadores de canais de cálcio. Polimorfismos do gene MDR-1, que codifica o transportador glicoproteína-P, influenciam a farmacocinética de várias drogas absorvidas no intestino, com destaque dado à digoxina. Vários outros polimorfismos relacionados a farmacodinâmica cardiovascular estão sendo estudados. Polimorfismos dos genes que codificam a enzima conversora da angiotensina e o angiotensinogênio parecem não afetar de forma consistente a resposta aos inibidores da enzima conversora da angiotensina. Polimorfismos dos receptores tipo 1 da angiotensina II e dos receptores beta-adrenérgicos modificam as respostas de seus respectivos antagonistas. Vários desafios devem ser superados para o sucesso da Farmacogenética em Cardiologia. O maior deles corresponde à validação clínica consistente de marcadores genéticos realmente capazes de prever respostas favoráveis ou toxidade a drogas

De una terapéutica de enfermedad a una terapéutica personalizada / From a disease therapeutic to a personalized therapeutic

La amplia decodificación del genoma humano y la simplificación de las técnicas empleadas para detectar polimorfismos y expresión génica han acelerado el desarrollo de la Medicina Predictiva, nueva rama de la Medicina, que permite evaluar el riesgo de padecer enfermedades con componente genético desde la vida prenatal. La Terapéutica Individual o Personalizada es un complemento de la Medicina Predictiva y también deriva del Proyecto Genoma Humano. En la Terapéutica Generalizada que se utiliza actualmente, los medicamentos son diseñados para controlar, mejorar o curar una enfermedad. Alternativamente, la principal finalidad de la Terapéutica Individual es producir medicamentos especialmente diseñados para el enfermo con el propósito de obtener una mejor respuesta terapéutica y evitar los efectos colaterales de la droga. La Farmacogenética y la Farmacogenómica son las dos disciplinas que generan la información necesaria para el diseño de la droga personalizada. La primera disciplina analiza el genotipo individual que metaboliza la droga y predice la estructura molecular de la droga que mejor se adapta al metabolismo del individuo. La Farmacogenómica estudia las mutaciones genéticas y las variaciones en la expresión génica involucradas en la forma clínica de las enfermedades con el fin de producir compuestos químicos específicos para el genotipo patogénico y de transcripción del paciente. La Terapéutica Individual ya ha producido cambios estructurales en el campo de la investigación farmacológica y en las estrategias comerciales de los laboratorios productores de drogas. Se espera que origine modificaciones marcadas en la práctica de la medicina clínica durante el transcurso de esta década.

Farmacogenética dos antidepressivos / Antidepressant pharmacogenetics

A farmacogenética pode ser definida como o estudo da variabilidade genética humana sobre a resposta do organismo à açäo de drogas. Os distúrbios farmacogenéticos representam variaçöes extremas nas respostas a drogas devido a um erro inato do metabolismo que envolve enzimas do sistema citocromal P450 (CYP P450). A maioria dos compostos antidepressivos é metabolizada pelo sistema CYP P450 humano. Dentre as 30 isoenzimas específicas conhecidas que compöe o sistema P450, apenas as CYP 1A2, 2C19, 3A3/4 e 2D6 participam do processo de biotransformaçäo das drogas antidepressivas e apenas as isoenzimas 2D6 e 2C19 estäo sujeitas a polimorfismo genético. Esse polimorfismo, por sua vez, pode produzir como conseqüência a atividade diminuída, rápida ou ultra-rápida da isoenzima separando a populaçäo em grupos de indivíduos metabolizadores lentos, rápidos e ultra-rápidos (COHEN & DE VANE, 1996). O conhecimento do polimorfismo genético, envolvendo o metabolismo dos antidepressivos, pode ajudar a desvendar graves problemas clínicos, tais como a ausência de respostas terapêuticas, efeitos adversos e toxicidade medicamentosa. Este trabalho apresenta uma coletânea de informaçöes da literatura sobre os fatores farmacogenéticos, envolvidos na resposta terapêutica a fármacos antidepressivos, destacando os aspectos clínico e bioquímico.