Rafael Baltazar Reyes León-Cachón

A pharmacogenetic pilot study reveals MTHFR, DRD3, and MDR1 polymorphisms as biomarker candidates for slow atorvastatin metabolizers

BackgroundThe genetic variation underlying atorvastatin (ATV) pharmacokinetics was evaluated in a Mexican population. Aims of this study were: 1) to reveal the frequency of 87 polymorphisms in 36 genes related to drug metabolism in healthy Mexican volunteers, 2) to evaluate the impact of these polymorphisms on ATV pharmacokinetics, 3) to classify the ATV metabolic phenotypes of healthy volunteers, and 4) to investigate a possible association between genotypes and metabolizer phenotypes.MethodsA pharmacokinetic study of ATV (single 80-mg dose) was conducted in 60 healthy male volunteers. ATV plasma concentrations were measured by high-performance liquid chromatography mass spectrometry. Pharmacokinetic parameters were calculated by the non-compartmental method. The polymorphisms were determined with the PHARMAchip® microarray and the TaqMan® probes genotyping assay.ResultsThree metabolic phenotypes were found in our population: slow, normal, and rapid. Six gene polymorphisms were found to have a significant effect on ATV pharmacokinetics: MTHFR (rs1801133), DRD3 (rs6280), GSTM3 (rs1799735), TNFα (rs1800629), MDR1 (rs1045642), and SLCO1B1 (rs4149056). The combination of MTHFR, DRD3 and MDR1 polymorphisms associated with a slow ATV metabolizer phenotype.ConclusionFurther studies using a genetic preselection method and a larger population are needed to confirm these polymorphisms as predictive biomarkers for ATV slow metabolizers.Trial registrationAustralian New Zealand Clinical Trials Registry: ACTRN12614000851662, date registered: August 8, 2014.

Phenotypic and molecular identification of Fonsecaea pedrosoi strains isolated from chromoblastomycosis patients in Mexico and Venezuela

Chromoblastomycosis is a chronic granulomatous disease caused frequently by fungi of the Fonsecaea genus. The objective of this study was the phenotypic and molecular identification of F. pedrosoi strains isolated from chromoblastomycosis patients in Mexico and Venezuela. Ten strains were included in this study. For phenotypic identification, we used macroscopic and microscopic morphologies, carbohydrate assimilation test, urea hydrolysis, cixcloheximide tolerance, proteolitic activity and the thermotolerance test. The antifungal activity of five drugs was evaluated against the isolates. Molecular identification was performed by sequencing the internal transcribed spacer (ITS) ribosomal DNA regions of the isolated strains. The physiological analysis and morphological features were variable and the precise identification was not possible. All isolates were susceptible to itraconazole, terbinafine, voriconazole and posaconazole. Amphotericin B was the least effective drug. The alignment of the 559‐nucleotide ITS sequences from our strains compared with sequences of GenBank revealed high homology with F. pedrosoi (EU285266.1). In this study, all patients were from rural areas, six from Mexico and four from Venezuela. Ten isolates were identified by phenotypic and molecular analysis, using ITS sequence and demonstrated that nine isolates from Mexico and Venezuela were 100% homologous and one isolate showed a small genetic distance.

Prediction of atorvastatin plasmatic concentrations in healthy volunteers using integrated pharmacogenetics sequencing

AIM To use variants found by next-generation sequencing to predict atorvastatin plasmatic concentration profiles (AUC) in healthy volunteers. SUBJECTS & METHODS A total of 60 healthy Mexican volunteers were enrolled in this study. We used variants with a predicted functional effect across 20 genes involved in atorvastatin metabolism to construct a regression model using a support vector approach with a radial basis function kernel to predict AUC refining it afterwards in order to explain a greater extent of the variance. RESULTS The final support vector regression model using 60 variants (including six novel variants) explained 94.52% of the variance in atorvastatin AUC. CONCLUSION An integrated analysis of several genes known to intervene in the different steps of metabolism is required to predict atorvastatins AUC.

Molecular identification of unusual Mycetoma agents isolated from patients in Venezuela

Mycetoma is a chronic granulomatous, subcutaneous disease endemic in tropical and subtropical countries. It is currently a health problem in rural areas of Africa, Asia and South America. Nine cases of mycetoma were analysed in a retrospective study. All isolates were identified by morphological features. The level of species identification was reached by molecular tools. Definitive identification of fungi was performed using sequence analysis of the ITS of the ribosomal DNA region and the ribosomal large‐subunit D1/D2. Identification of actinomycetes was accomplished by the 16S rRNA gene sequence. Six unusual clinical isolates were identified: Aspergillus ustus, Cyphellophora oxyspora, Exophiala oligosperma, Madurella pseudomycetomatis, Nocardia farcinica and Nocardia wallacei. The prevalence of mycetoma in Venezuela remains unknown. This study represents the first report in the literature of mycetoma caused by unusual pathogens identified by molecular techniques.

Real-time PCR Detection of the Recessive Dystrophic Epidermolysis Bullosa-associated c.2470insG Mutation in Unrelated Mexican Families

Recessive dystrophic epidermolysis bullosa (R-DEB) is caused by mutations in the COL7A1 gene. The most common mutation reported in Mexican families is the c.2470insG mutation, normally detected by DNA sequencing. We report a faster and more economical high-throughput genotyping method to detect the c.2470insG mutation using specific TaqMan probes in a real-time polymerase chain reaction (RT-PCR) that facilitates genotype analysis with allelic discrimination plots. Our new method correctly genotyped 45 samples that had previously been sequenced as 41 wild-type homozygous (-/-), 1 heterozygous (-/G) and three mutant homozygous (G/G) (100% specificity). This new method allows high-throughput screening and furthermore is economical (

ACE, APOA5, and MTP Gene Polymorphisms Analysis in Relation to Triglyceride and Insulin Levels in Pediatric Patients

3 US/sample), fast (2 h), and sensitive as it requires only 20 ng input DNA. We used the new test to genotype 89 individuals from 32 unrelated Mexican families with R-DEB. The observed genotypic frequencies were 93.3% for the homozygous wild-type and 6.7% for the heterozygous genotype. The homozygous mutant genotype was not found. In conclusion, the allelic discrimination assay by RT-PCR is a sensitive, specific and effective high-throughput test for detecting the c.2470insG mutation.

Individual response to drug therapy: bases and study approaches

BACKGROUND AND AIMS Obesity is a complex, chronic, and multifactorial disease that has become a major, and worldwide, public health problem contributing to an increased number of pathologies, including type 2 diabetes, cardiovascular disease, hyperlipidemia, and metabolic syndrome, thus suggesting a commolon origin. A diet high in sugar and fats coupled with a sedentary lifestyle has a major role in the development of obesity. However, the genetic background has also been associated with body fat accumulation. The aim of this study was to assess the effect ofACE-rs4646994, APOA5-rs662799, and MTP-rs1800591 gene polymorphisms on clinical and biochemical parameters and to evaluate the association with body phenotypes in children and adolescent population of Saltillo, Coahuila, Mexico. METHODS Anthropometric, clinical, biochemical parameters and BMI were obtained from 405 children and adolescents. The BMI was used to determine the body phenotype. The rs4646994 gene polymorphism was determined by PCR, whereas rs662799 and rs1800591 were determined by PCR-RFLP. The obtained results were analyzed to determine their association of these single nucleotide polymorphisms with body phenotype and biochemical parameters. RESULTS TT genotype for APOA5-rs662799 was associated with increased levels of HDL-C in the analyzed population (p <0.05). The ACErs4646994gene polymorphism is associated with high Insulin levels, HOMAIR index, and triglyceride levels, mainly when presenting a I/I genotype (p <0.05). CONCLUSION The polymorphic allele of the ACE gene is capable of modulating triglyceride levels, insulin levels and HOMA-IR index in the evaluated population; it must be highlighted that this has not been reported in other studied populations elsewhere.