Tratamiento del tabaquismo guiado por marcadores genéticos

Introducción: Entre las adicciones por drogas, el tabaquismo ocupa el primer lugar como causa de morbimortalidad y es factor de riesgo para seis de las ocho principales causas de muerte en el mundo. La nicotina es el principal componente adictivo del tabaco. En la terapia de reemplazo con nicotina (TRN), la vareniclina y el bupropion son los medicamentos aprobados para tratamiento del tabaquismo, pero los resultados de las clínicas de dejación del tabaquismo sugieren que aún se desconoce muchas variables influyentes en la respuesta al tratamiento. Objetivo: Determinar la adherencia, la tolerabilidad y la efectividad de un programa de dejación de tabaquismo basado en nicotina o bupropion, en pacientes con dependencia al tabaco, seleccionados según los genotipos de las enzimas que metabolizan los dos fármacos. Hallazgos clínicos: Se incluyeron en esta serie 21 fumadores, 67% hombres, con edad promedio de 46,2±11,7 años. Su tabaquismo comenzó a los 17,8±6 años y llevaban fumando 28±13 años. Al inicio del estudio fumaban 17±12 cigarrillos por día (CPD), habían hecho 3,7±2 intentos de dejar de fumar y el puntaje NDSS (escala breve de evaluación de dependencia de la nicotina, por sus siglas en inglés) fue de 22±5 (punto de corte para dependencia a nicotina: 11 o más puntos). Tratamiento: Los pacientes tenían libre acceso telefónico al médico tratante y, cada semana, una consulta consistente en consejería y control del tratamiento farmacológico prescrito según los genotipos CYP2A6 (que codifica la enzima que metaboliza la nicotina) y CYP2B6 (que codifica la enzima que metaboliza el bupropion). Se empleó nicotina en parches transdérmicos de 14 mg el primer mes y luego de 7 mg el segundo mes, complementados con chicles para manejo del síndrome de abstinencia y bupropion en forma de liberación regulada por 300 mg, 1-2 veces al día. Resultados: Después de 8 semanas de tratamiento y 4 de observación, 15 sujetos (71,4%) respondieron en forma parcial/total. El consumo de CPD bajó de 17±12 al inicio del estudio, a 2,2±3,5 al final del estudio, que corresponde a una reducción de 195 cigarrillos/día. Siete de ocho pacientes tratados con bupropion (87,5%) y siete de trece tratados con nicotina (54%) tuvieron respuesta parcial/total. Solo un paciente formulado con nicotina suspendió el medicamento por intolerancia gastrointestinal (náusea y vómito). La tasa de recaídas, evaluada un mes después del tratamiento farmacológico, fue de cero. Se encontró buena correlación genotipo-fenotipo en los individuos tratados con bupropion, pero no en los tratados con nicotina. Relevancia clínica: La inclusión de marcadores farmacogenéticos para la elección de nicotina o bupropion en un programa de dejación de tabaquismo puede mejorar la adherencia, la tolerabilidad al fármaco y la efectividad del tratamiento.

Introduction: Among drug addictions, smoking ranks first as a cause of morbidity and mortality and is a risk factor for six of the eight leading causes of death in the world. Nicotine is the main addictive component of tobacco. In nicotine replacement therapy (NRT), varenicline and bupropion are the approved medications for smoking cessation, but results from smoking cessation clinics suggest that many variables influencing response to treatment remain unknown. Objective: To determine the adherence, tolerability and effectiveness of a smoking cessation program based on nicotine or bupropion, in patients with tobacco dependence, selected according to the genotypes of the enzymes that metabolize the two drugs. Clinical findings: Twenty-one smokers were included in this series, 67% men, with a mean age of 46.2 ± 11.7 years. Their smoking began at 17.8±6 years and they had been smoking for 28±13 years. At baseline, they smoked 17±12 cigarettes per day (CPD), had made 3.7±2 quit attempts, and the NDSS score it was 22±5 (cut-off point for nicotine dependence: 11 or more points). Treatment: The patients had free telephone access to the treating physician and, every week, a consultation consisting of counseling and control of the pharmacological treatment prescribed according to the CYP2A6 genotypes (encoding the enzyme that metabolizes nicotine) and CYP2B6 (coding for the enzyme that metabolizes bupropion). Nicotine was used in transdermal patches of 14 mg the first month and then 7 mg the second month, supplemented with gum to manage the withdrawal syndrome and bupropion in the form of controlled release 300 mg, 1-2 times a day. Results: After 8 weeks of treatment and 4 weeks of observation, 15 subjects (71.4%) responded partially/totally. CPD consumption dropped from 17±12 at the beginning of the study to 2.2±3.5 at the end of the study, which corresponds to a reduction of 195 cigarettes/day. Seven of eight patients treated with bupropion (87.5%) and seven of thirteen treated with nicotine (54%) had a partial/total response. Only one patient receiving nicotine discontinued the medication due to gastrointestinal intolerance (nausea and vomiting). The relapse rate, assessed one month after drug treatment, was zero. Good genotype-phenotype correlation was found in individuals treated with bupropion, but not in those treated with nicotine. Clinical relevance: The inclusion of pharmacogenetic markers for the choice of nicotine or bupropion in a smoking cessation program may improve adherence, drug tolerability, and treatment effectiveness.

An updated examination of the perception of barriers for pharmacogenomics implementation and the usefulness of drug/gene pairs in Latin America and the Caribbean.

Pharmacogenomics (PGx) is considered an emergent field in developing countries. Research on PGx in the Latin American and the Caribbean (LAC) region remains scarce, with limited information in some populations. Thus, extrapolations are complicated, especially in mixed populations. In this paper, we reviewed and analyzed pharmacogenomic knowledge among the LAC scientific and clinical community and examined barriers to clinical application. We performed a search for publications and clinical trials in the field worldwide and evaluated the contribution of LAC. Next, we conducted a regional structured survey that evaluated a list of 14 potential barriers to the clinical implementation of biomarkers based on their importance. In addition, a paired list of 54 genes/drugs was analyzed to determine an association between biomarkers and response to genomic medicine. This survey was compared to a previous survey performed in 2014 to assess progress in the region. The search results indicated that Latin American and Caribbean countries have contributed 3.44% of the total publications and 2.45% of the PGx-related clinical trials worldwide thus far. A total of 106 professionals from 17 countries answered the survey. Six major groups of barriers were identified. Despite the region's continuous efforts in the last decade, the primary barrier to PGx implementation in LAC remains the same, the "need for guidelines, processes, and protocols for the clinical application of pharmacogenetics/pharmacogenomics". Cost-effectiveness issues are considered critical factors in the region. Items related to the reluctance of clinicians are currently less relevant. Based on the survey results, the highest ranked (96%-99%) gene/drug pairs perceived as important were CYP2D6/tamoxifen, CYP3A5/tacrolimus, CYP2D6/opioids, DPYD/fluoropyrimidines, TMPT/thiopurines, CYP2D6/tricyclic antidepressants, CYP2C19/tricyclic antidepressants, NUDT15/thiopurines, CYP2B6/efavirenz, and CYP2C19/clopidogrel. In conclusion, although the global contribution of LAC countries remains low in the PGx field, a relevant improvement has been observed in the region. The perception of the usefulness of PGx tests in biomedical community has drastically changed, raising awareness among physicians, which suggests a promising future in the clinical applications of PGx in LAC.

Influence of CYP2B6 Genotype on Methadone Dosage in Patients from the Methadone Maintenance Treatment (MMT) Program in Pereira, Colombia.

Methadone treatment reduces the use of heroin and withdrawal symptoms; however, methadone is an expensive medication with a narrow safety margin. We compared the retention rates, persistence of heroin use, and quality of life of a group of patients undergoing conventional Methadone Maintenance Treatment (MMT) with a group for whom the CYP2B6 516G>T polymorphism was used in addition to the MMT to calculate the required methadone dose. Over 12 weeks, the retention rate, heroin usage, and quality of life of patients under conventional treatment (n = 34) were compared with those of patients for whom we used genetic markers to calculate methadone dosage (n = 38). At the end of the study, 26.4% of patients abandoned the program, and neither demographic nor clinical variables were associated with treatment adherence. Of the remaining patients, 16% of the control group and 8% of patients in the pharmacogenetic group reported heroin use, while both groups showed a 64% reduction in the use of cocaine/crack (no significant differences between the groups were found). Starting in the second week, the methadone dosage was lower among the patients for whom methadone was prescribed based on genotype. Although there were six individuals in the control group and three in the pharmacogenetic group with QTc intervals > 450 ms (a threshold that is considered dangerous), we did not find a relationship between the QTc interval and methadone dosage. There were no differences in the perception of quality of life between the two groups. The results of this pilot study suggest that concerning methadone therapy, the CYP2B6 genotype contributes to reduced effective doses and treatment costs.

Surveillance of the Antimicrobial Resistance Rates of Helicobacter pylori Ten Years Later in the Western Central Region, Colombia.

BACKGROUND: Helicobacter pylori is a bacterium associated with gastroduodenal disease and gastric cancer. Empirical therapy in the treatment of H. pylori infection increases the risk of apparition of antimicrobial drug resistance. In a previous report, in H. pylori clinical isolates, resistance rates to commonly used antimicrobial drugs were as follows: metronidazole 82%, clarithromycin 3.8%, and amoxicillin 1.9%. The aim was to establish the variation of resistance rates and the detection of H. pylori genetic mutations isolated from dyspeptic patients. METHODS: Antimicrobial susceptibility profiles were performed by the E-test method for metronidazole, clarithromycin, amoxicillin, and tetracycline in 61 clinical isolates. Sequencing was performed to detect mutations associated with resistance to clarithromycin. RESULTS: According to our results, resistance rates found in the 61 isolates were 78.60% for metronidazole and 8.20% for clarithromycin. None of the studied isolates had resistance to tetracycline and amoxicillin. Secondary resistance rates displayed an increase when compared to primary rates for metronidazole (87.50 vs. 77.35%) and for clarithromycin (25.66 vs. 5.66%). Of 5 isolates resistant to clarithromycin, 3 had the A2143G mutation. By comparing the results in this work with previous reports, antimicrobial drug resistance rates did not show major modifications for metronidazole, amoxicillin, and tetracycline during the last 10 years. For clarithromycin, the resistance rate showed a moderate increase; nevertheless, it remains low (<15%) and this change was not statistically significant. CONCLUSION: Together, all findings in this work indicate that these antimicrobial drugs can still be used as first line of defense on infected patients living in this region of the country.

Caracterización del gen de la dopamina Beta-hidroxilasa en población mestiza colombiana / Caracterization of dopamine Beta-hydroxylase gene in the Colombian Mestizo Population / Caracterização do gene da dopamina Beta-hidroxilasa em população mestiça

Introducción: la dopamina β-hidroxilasa cataliza la conversión de dopaminaen norepinefrina y es blanco promisorio de intervenciones farmacológicas.Polimorfismos del gen DβH son responsables de las diferencias individuales en el tono dopaminérgico y adrenérgico de los sistemas nervioso central y autónomo. Ya que las mutaciones defectuosas de la enzima y sus frecuencias varían entre las etnias, se justifican los estudios conducentes a la caracterización genotípica yfenotípica de la enzima en mestizos colombianos. Métodos: determinamos las frecuencias de los alelos -2073C>T, -970C>T, 444A>G y 1603C>T del gen DβH en 143 adultos sanos, rasgos mestizos, ambos sexos y no consanguíneos. La genotipificación se hizo por PCR-real time y minisecuenciación (SnaPshot).Resultados: las frecuencias de los genotipos polimórficos fueron: -2073C>T (CC 61,5%, CT 32,9%, TT 5,6%), -970C>T (CC 49,6%, CT 43,4, TT 7%) y 444A>G (AA 42%, AG 41,2%, GG 16,8%). Las tres mutaciones están en desequilibrio de ligamiento (D´=1) pero no se sustituyen mutuamente (r2<0,8). 15 personas (10,5%) tuvieron haplotipo de triple homocigoto nativo (CC/CC/AA). Conclusión: nuestras frecuencias alélicas se asemejan a las reportadas en otros grupos mestizos latinoamericanos.

Introduction: dopamine P- hidroxylase catalyzes the conversion of dopamine to norepinephrine and it is a promising target for pharmacological inventions. DPH gene polymorphisms are responsible for individual differences in dopaminergic and adrenergic tone of the central and autonomic nervous systems. Since defective enzyme mutations and their frequencies vary among ethnic groups, it is justify the studies leading to the genotypic and phenotypic characterization of the enzyme in Colombian mestizos.Methods: we determined the frequencies of the alleles -2073C>T, -970C>T, 444A>G and 1603C>T DfiH gene in 143 healthy adults, mestizo features, both sexes and nonconsanguineous. PCR-real time and minisequencing (SnaPshot) tecnhiques were used for the genotyping.Results: the frequencies of polymorphic genotypes were: -2073C>T (CC 61,5%, CT 32,9%, TT 5,6%), -970C>T (CC 49,6%, CT 43,4, TT 7%) and 444A>G (AA 42%, AG 41,2%, GG 16,8%).The three alleles are in linkage disequilibrium (D'=1) but they do not replace each other (r2<0,8). 15 people (10,5%) had the homozygous triple native haplotype (CC/CC/AA).Conclusion: our allelic frequencies are similar to those reported in other Latin American mestizo groups.

Introdução: a dopamina P-hidroxilasa catalisa a conversão de dopamina em norepinefrina e é alvo promissor de intervenções farmacológicas. Polimorfismos do gene DfiH são responsavéis pelas diferenças individuais no tom dopaminérgico e adrenérgico dos sistemas nervoso central e autonomo. Como as mutações defeituosas da enzima e suas frequências variam entre as etnias, se justificam os estudos conduzentes à caracterização da e fenotípica da enzima en mestiços colombianos.Métodos: determinamos as frequencias alelos -2073C>T, -970C>T, 444A>G e 1603C>T do gene DfiH em 143 adultos sãos, traços mestiços, ambos sexos e não consanguíneos. A genotipificação se fez por PCR-real time e minisequência (SnaPshot).Resultados: as frequências dos genotipos polimórficos foram: -2073C>T (CC 61,5%, CT 32,9%, TT 5,6%), -970C>T (CC 49,6%, CT 43,4, TT 7%) e 444A>G (AA 42%, AG 41,2%, GG 16,8%). As três mutações estão em desiquilibrio de ligamiento (D'=1) mas não se substituem mutuamente (r2<0,8). 15 pessoas (10,5%) tiveram haplotipo de triple homocigoto nativo (CC/CC/AA).Conclusão: nossas frequências alélicas se assemelham às lembradas em outros grupos mestiças latino-americanos.