Carlos Isaza

Phenotype-genotype analysis of CYP2C19 in Colombian mestizo individuals

BackgroundOmeprazole is metabolized by the hepatic cytochrome P450 (CYP) 2C19 enzyme to 5-hydroxyomeprazole. CYP2C19 exhibits genetic polymorphisms responsible for the presence of poor metabolizers (PMs), intermediate metabolizers (IMs) and extensive metabolizers (EMs). The defective mutations of the enzyme and their frequencies change between different ethnic groups; however, the polymorphism of the CYP2C19 gene has not been studied in Colombian mestizos. The aim of this study was to evaluate the genotype and phenotype status of CYP2C19 in Colombian mestizos, in order to contribute to the use of appropriate strategies of drug therapy for this population.Methods189 subjects were genotyped using the multiplex SNaPshot technique and a subgroup of 44 individuals received 20 mg of omeprazole followed by blood collection at 3 hours to determine the omeprazole hydroxylation index by HPLC.Results83.6%, 15.3% and 1.1% of the subjects were genotyped as EMs, IMs and PMs, respectively. The frequencies of the CYP2C29*1 and CYP2C19*2 alleles were 91.3% and 8.7% respectively whereas the *3, *4, *5, *6 and *8 alleles were not found. No discrepancies were found between the genotype and phenotype of CYP2C19.ConclusionThe frequency of poor metabolizers (1.1%) in the Colombian mestizos included in this study is similar to that in Bolivian mestizos (1%) but lower than in Mexican-Americans (3.2%), West Mexicans (6%), Caucasians (5%) and African Americans (5.4%). The results of this study will be useful for drug dosage recommendations in Colombian mestizos.

β2‐adrenoreceptor polymorphisms in asthmatic and non‐asthmatic schoolchildren from colombia and their relationship to treatment response

Asthma is a chronic and recurrent disease. Its high prevalence around the world is the result of a complex interaction between genetic and environmental factors. The genetic aspects of susceptibility, severity, and response to treatment in asthma are of great scientific interest. The purpose of the study was to establish the relationship between the Gln27Glu and Arg16Gly alleles of the β2‐adrenergic receptor (ADRB2) gene with respect to the susceptibility to and severity of asthma, as well as the response to treatment in mestizo schoolchildren. 109 schoolchildren with asthma diagnosis and 137 asymptomatic controls were genotyped for the Arg16Gly and Gln27Glu alleles of the ADRB2 gene by minisequencing. Allele, genotype, and haplotype frequencies of the ADRB2 gene between asthmatic and non‐asthmatic as well as demographic, clinical, and spirometric variables among asthmatic patients according to their genotype were compared. ADRB2 gene expression was determined by real‐time quantitative PCR. No statistical differences were found in allele, genotype, and haplotype frequencies of the ADRB2 gene between cases and controls. We did not find differences between asthmatic patients classified according to their ADRB2 genotypes and haplotypes when evaluating demographic, clinical, and spirometric variables. The ADRB2 genotype and haplotype are not associated with spirometric responses or ADRB2 gene expression after administration of a β‐2 agonist plus a glucocorticoid. These results suggest that in the group of mestizo schoolchildren studied, the Arg16Gly and Gln27Glu polymorphisms are not markers of susceptibility or severity of asthma and do not affect ADRB2 gene expression during the rescue therapy. Pediatr Pulmonol. 2012. 47:848–855.

Beta-2-Adrenergic Receptor Polymorphisms and Changes in Lipids Induced by Metoprolol

Polymorphisms Arg₁₆Gly and Gln₂₇Glu of the gene of adrenoreceptor β₂(ADRB2) are associated with altered sympathetic responses. This study evaluated the relationship between these polymorphisms and changes in lipids induced by metoprolol in hypertensive patients. 105 adults were enrolled. After serum lipid levels and genotype had been determined, metoprolol was administered orally. Genotyping was performed using a mini-sequencing technique. Allelic and genotypic frequencies were: Arg₁₆ (49.5%); Gly₁₆ (50.5%); Gln₂₇ (89%); Glu₂₇ (11%); Arg₁₆Arg (28.6%); Arg₁₆Gly (41.9%); Gly₁₆Gly (29.5%); Gln₂₇Gln (81%); Gln₂₇Glu (16.1%), and Glu₂₇Glu (2.9%). Ninety patients concluded the study. There were no significant differences between the demographic, pharmacological and biochemical variables evaluated, grouped by their genotype in positions 16 and 27 of the ADRB2 gene. We did not find differences in lipid profiles in the whole group, but when we compared these profiles within each genotypic subgroup, we found that total cholesterol diminished (p = 0.03) in the patients with the native Gln₂₇Gln genotype, whereas in the Gln₂₇Glu heterozygous triglycerides increased (p = 0.025). We only found 3 patients homozygous for Glu₂₇Glu and 2 of them were treated with diet and antidyslipidemic drugs. These results suggest that the polymorphism of codon 27 constitutes the target of the changes in lipids induced by β-adrenergic receptor antagonists.

Hepatitis B and C prevalence among heroin addicts in methadone maintenance treatment (MMT) and not in MMT in Pereira, Colombia

This is an open-access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In a recent systematic review, Nelson et al showed that injection drug abuse is an important factor associated with a high prevalence of hepatitis C virus (HCV) and hepatitis B virus (HBV) infection [1]. In that review, only data from Argentina, Brazil, Mexico, Paraguay and Uruguay were included, due to the lack of information on other countries in Latin America and in the Caribbean. After an extensive literature search about the prevalence of injection drug use in Colombia, only four reports were found on three different Colombian cities. The prevalence of intravenous heroin administration in Medellin ranges between 0.2% in a prison population (VESPA Survey reported by Castaño) [2] and 24% in drug addiction treatment centers [3]. However, a comparison between both studies cannot be carried out due to differences in sample size, methodology and population evaluated. In Bucaramanga, the prevalence of intravenous illegal drug use in three drug rehabilitation centers and one prison was 4.2% [4]. Finally, a survey carried out on 895 inhabitants from Pereira showed a prevalence of intravenous drug use of 26.9%, including the use of heroin and cocaine [5] (Figure 1). Hepatitis C virus (HCV) testing and counseling are important strategies to potentially reduce HCV transmission in young adult injection drug users [6]. However, in developing countries, the health systems underappreciate the role of injection drug users (IDU) in the transmission of infectious agents such as HCV, hepatitis B virus (HBV) and human immunodeficiency virus (HIV). Moreover, the treatment of HCV infection in IDU is still low in developing countries due to patient-and system-related barriers. Although HCV infection is a public health problem around the world and chronic viral hepatitis are the major etiological factors of end-stage liver diseases, in Colombia there are no studies of HCV and HBV prevalence in IDU. The prevalence of HCV in multi-transfused patients is 9% [7], whereas a more recent study carried out in 697 inhabitants from four different states showed a frequency of anti-HCV markers of 3.55% [8]. On the other hand, the prevalence of HBV in Colombia ranges between 1.97 and 8.39% in several regions [8-10]. As part of an ongoing work evaluating the immune status of IDU and a control population in Pereira, Colombia (approved by the …

Evaluación del programa de mantenimiento con metadona del Hospital Mental de Risaralda

BACKGROUND Psychosocial care and methadone maintenance treatment (MMT) are the preferred strategies for the management of heroin addicts, but the results are still unsatisfactory, justifying the search and intervention of the factors influencing the response to treatment. METHODOLOGY In order to determine the contribution of demographic, clinical and genetic variables on serum concentrations and response to methadone, we investigated patients on MMT, who were receiving methadone in supervised and unchanged doses at least during the previous two weeks. The age, gender, body mass index (BMI), duration of heroin abuse, addiction to other drugs, criminal background, current daily methadone doses, time spent in the TMM, comorbidity and concomitant medication were recorded. Blood samples were taken for the determination of serum levels of racemic methadone and its R and S-enantiomers, and for typing of candidate alleles of POR, CYP2B6, ABCB1, GRIN1, OPRM1, SLC6A3, DßH and ARRB2 genes, all associated with the metabolism, tissue distribution and mechanism of action of methadone. Methadone quantification was by HPLC-DAD, and the detection of genetic markers by Real Time PCR and VNTR methods. RESULTS A total of 80 subject volunteers were enrolled, with a mean age of 23.5 (5) years (86% male), all of them were addicts of multiple drugs, 60% with a criminal background, 5.1 (2.9) years taking heroin, and 5.3 (4) months on MMT, and taking a supervised dose of 41 (12) mg/day methadone. The (R), (S) and (R, S) methadone enantiomer trough plasma levels were, 84 (40), 84 (42), and 168 (77) ng/mL, respectively. All genotypes were in Hardy-Weinberg equilibrium. The two urine tests were negative for heroin in 61.3% (49/80) of the volunteers, the decline in cocaine/crack use was 83%, 30% of marijuana, and other psychoactives (inhalants, benzodiazepines, amphetamines) decreased to zero, while the consumption of snuff remained at 93.5% (75/80). Blood concentrations of racemic methadone and its enantiomers were significantly associated with the dose/day of the medication, but none of the other demographic, clinical or genetic variables impacted on serum levels of methadone. As for the results of the MMT, non-users and occasional users of heroin, as well as those who stopped taking other psychoactive drugs, and the ones who did not, were similar as regards the demographic, genetic and clinical variables. This included the blood metahdone concentrations, except for individuals who did not reduce their consumption of other psychoactives other than heroin, who had significantly (P=.03) higher blood levels of S-methadone, compared with those who did stop taking them. CONCLUSIONS There was a significant reduction in the consumption of heroin and other psychoactives, and social rehabilitation of patients. However, the extensive overlap between effective and ineffective doses of methadone suggests the presence of personal and social variables that transcend the simple pharmacological management. These probably need to be addressed more successfully from the psychosocial features, particularly as regards to identifying and overcoming relapse-trigger experiences, as well as certain features of the patient, such as their psychological distress level or their psychiatric disorders.

Artículo originalEvaluación del programa de mantenimiento con metadona del Hospital Mental de RisaraldaEvaluation of the Methadone Maintenance Program of the Risaralda Mental Hospital

BACKGROUND Psychosocial care and methadone maintenance treatment (MMT) are the preferred strategies for the management of heroin addicts, but the results are still unsatisfactory, justifying the search and intervention of the factors influencing the response to treatment. METHODOLOGY In order to determine the contribution of demographic, clinical and genetic variables on serum concentrations and response to methadone, we investigated patients on MMT, who were receiving methadone in supervised and unchanged doses at least during the previous two weeks. The age, gender, body mass index (BMI), duration of heroin abuse, addiction to other drugs, criminal background, current daily methadone doses, time spent in the TMM, comorbidity and concomitant medication were recorded. Blood samples were taken for the determination of serum levels of racemic methadone and its R and S-enantiomers, and for typing of candidate alleles of POR, CYP2B6, ABCB1, GRIN1, OPRM1, SLC6A3, DßH and ARRB2 genes, all associated with the metabolism, tissue distribution and mechanism of action of methadone. Methadone quantification was by HPLC-DAD, and the detection of genetic markers by Real Time PCR and VNTR methods. RESULTS A total of 80 subject volunteers were enrolled, with a mean age of 23.5 (5) years (86% male), all of them were addicts of multiple drugs, 60% with a criminal background, 5.1 (2.9) years taking heroin, and 5.3 (4) months on MMT, and taking a supervised dose of 41 (12) mg/day methadone. The (R), (S) and (R, S) methadone enantiomer trough plasma levels were, 84 (40), 84 (42), and 168 (77) ng/mL, respectively. All genotypes were in Hardy-Weinberg equilibrium. The two urine tests were negative for heroin in 61.3% (49/80) of the volunteers, the decline in cocaine/crack use was 83%, 30% of marijuana, and other psychoactives (inhalants, benzodiazepines, amphetamines) decreased to zero, while the consumption of snuff remained at 93.5% (75/80). Blood concentrations of racemic methadone and its enantiomers were significantly associated with the dose/day of the medication, but none of the other demographic, clinical or genetic variables impacted on serum levels of methadone. As for the results of the MMT, non-users and occasional users of heroin, as well as those who stopped taking other psychoactive drugs, and the ones who did not, were similar as regards the demographic, genetic and clinical variables. This included the blood metahdone concentrations, except for individuals who did not reduce their consumption of other psychoactives other than heroin, who had significantly (P=.03) higher blood levels of S-methadone, compared with those who did stop taking them. CONCLUSIONS There was a significant reduction in the consumption of heroin and other psychoactives, and social rehabilitation of patients. However, the extensive overlap between effective and ineffective doses of methadone suggests the presence of personal and social variables that transcend the simple pharmacological management. These probably need to be addressed more successfully from the psychosocial features, particularly as regards to identifying and overcoming relapse-trigger experiences, as well as certain features of the patient, such as their psychological distress level or their psychiatric disorders.

Comparación de dos protocolos de erradicación de Helicobacter pylori

Introduccion. Los principales determinantes del resultado del tratamiento anti-Helicobacter pylori son la susceptibilidad a los antimicrobianos y, en el caso de inhibidores de la bomba de protones, el genotipo CYP2C19 del paciente. Objetivos. Con miras a definir esquemas terapeuticos que tengan en cuenta tales variables nos propusimos comparar seguridad y eficacia de dos regimenes anti-H. pylori. Materiales y metodos. El estudio incluyo 41 pacientes dispepticos con H. pylori positivo (38±14 anos, 55,8% mujeres), quienes se trataron durante una semana con 1 g/dia de claritromicina y 2 g/dia de amoxicilina, mas uno de los siguientes antiulcerosos: 800 mg/dia de ranitidina bismuto citrato (n=22), o 40 mg/dia de omeprazol (n=19). La erradicacion de la infeccion fue considerada cuando el test de antigenos fecales de H. pylori fue negativo 4-6 semanas despues del tratamiento. Resultados. No hubo diferencias significativas entre los grupos respecto a variables biologicas y tolerabilidad al tratamiento. En el analisis “por intencion de tratar” los dos regimenes resultaron similares en sus tasas de erradicacion de la bacteria (79% omeprazol vs 91% ranitidina bismuto citrato, P=0,39). Se encontraron las mutaciones bacterianas A2142G y A2143G, asociadas con resistencia del H. pylori a la claritromicina, en tres de los cuatro pacientes en quienes fracaso el tratamiento. Conclusiones. Los esquemas basados en omeprazol o en ranitidina bismuto citrato, son comparables en efectividad y seguridad para el tratamiento de la infeccion por H. pylori. La resistencia de la bacteria a la claritromicina es la principal causa del fracaso en su erradicacion.

Comparación de los genotipos CYP2C19 entre caucásico español y mestizo colombiano

Algunos alelos del gen CYP2C19 producen enzima con actividad catalitica defectuosa, pero este gen no ha sido caracterizado en mestizo suramericano ni en caucasico espanol. Nos propusimos determinar la prevalencia y comparar los alelos CYP2C19*1 (nativo), CYP2C19*2, CYP2C19*3, CYP2C19*4, CYP2C19*5, CYP2C19*6 y CYP2C19*8 en muestras de poblacion mestiza colombiana y caucasica espanola. Para ello genotipificamos 189 colombianos y 183 espanoles mediante la tecnica de mini-secuenciacion con el ABI Prism SNaPshot Multiplex System. Entre los colombianos encontramos 83.6% de portadores de los dos alelos nativos (fenotipo EM, metabolizador rapido), 15.3% de heterocigotos para un alelo no funcional (fenotipo IM, metabolizador intermedio) y dos personas (1.1%) portadoras de los dos alelos no funcionales (fenotipo PM, metabolizador pobre). El 77% de espanoles son portadores de los dos alelos nativos (EM), 21.8% son heterocigotos para un alelo no funcional (IM) y el 1.1% son homocigotos *2/*2 (PM). El equilibrio de Hardy-Weinberg se confirmo para la distribucion genotipica de ambos grupos. En los dos grupos la variante mutada *2 fue la mas frecuente, solo en un individuo espanol se encontro el alelo *4, y los alelos *3, *5, *6 y *8 no se hallaron en ninguno de los dos grupos. No hubo diferencias significativas en las prevalencias alelicas y genotipicas de los dos grupos etnicos comparados, lo cual permite suponer que tambien sean semejantes las respuestas farmacogeneticas relacionadas con el metabolismo de los medicamentos que son sustratos de la enzima CYP2C19.