Rome III Criteria Capture Higher Irritable Bowel Syndrome SNP-Heritability and Highlight a Novel Genetic Link With Cardiovascular Traits.

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) shows genetic predisposition, and large-scale genome-wide association studies (GWAS) are emerging, based on heterogeneous disease definitions. We investigated the genetic architecture of IBS defined according to gold standard Rome Criteria. METHODS: We conducted GWAS meta-analyses of Rome III IBS and its subtypes in 24,735 IBS cases and 77,149 asymptomatic control subjects from 2 independent European cohorts (UK Biobank and Lifelines). Single-nucleotide polymorphism (SNP)-based heritability (h2SNP) and genetic correlations (rg) with other traits were calculated. IBS risk loci were functionally annotated to identify candidate genes. Sensitivity and conditional analyses were conducted to assess impact of confounders. Polygenic risk scores were computed and tested in independent datasets. RESULTS: Rome III IBS showed significant SNP-heritability (up to 13%) and similar genetic architecture across subtypes, including those with manifestations at the opposite ends of the symptom spectrum (rg = 0.48 between IBS-D and IBS-C). Genetic correlations with other traits highlighted commonalities with family history of heart disease and hypertension, coronary artery disease, and angina pectoris (rg = 0.20-0.45), among others. Four independent GWAS signals (P < 5×10-8) were detected, including 2 novel loci for IBS (rs2035380) and IBS-mixed (rs2048419) that had been previously associated with hypertension and coronary artery disease. Functional annotation of GWAS risk loci revealed genes implicated in circadian rhythm (BMAL1), intestinal barrier (CLDN23), immunomodulation (MFHAS1), and the cyclic adenosine monophosphate pathway (ADCY2). Polygenic risk scores allowed the identification of individuals at increased risk of IBS (odds ratio, 1.34; P = 1.1×10-3). CONCLUSIONS: Rome III Criteria capture higher SNP-heritability than previously estimated for IBS. The identified link between IBS and cardiovascular traits may contribute to the delineation of alternative therapeutic strategies, warranting further investigation.

Estudio de biodisponibilidad de metformina 850 mg tabletas de liberación inmediata / Bioavalability study of Metformin 850 mg immediate-release tablets

Se desarrolló un estudio de biodisponibilidad de metformina 850 mg tabletas recubiertas de liberación inmediata elaboradas por Laboratorios Coaspharma S.A., en 12 voluntarios sanos de ambos sexos, con edades entre 18 y 26 años. Para llevarlo a cabo se validó previamente un método bioanalítico para la determinación de metformina en plasma humano por cromatografía líquida de alta resolución con detector ultravioleta (HPLC-UV), el cual resultó ser selectivo, específico, lineal, exacto y preciso, por lo tanto adecuado para el análisis de las muestras. Estas fueron recolectadas periódicamente en un lapso desde 0 a 24 horas, luego de la administración por vía oral de una única dosis de metformina 850 mg. Posteriormente se determinaron los parámetros farmacocinéticos promedio de los 12 participantes, obteniendo: área bajo la curva, desde tiempo cero hasta el último tiempo de muestreo t (AUC0--->t) 6856,89 ± 2073,8 ng.h/ml, área bajo la curva desde tiempo cero hasta tiempo infinito (AUC0--->∞) 7083,74 ± 2131,52 ng.h/ml, concentración máxima (Cmaxmax) 1299,02 ± 291,90 ng/ml, tiempo máximo (t) 2,33 ± 0,47 h, tiempo de vida media (t1/2) 2,50 ± 0,84 h y constante aparente de eliminación (Ke) de 0,31 ± 0,12 h-1. Los resultados fueron similares en todos los participantes y no se produjeron reacciones adversas.

A bioavailability study was conducted in 12 healthy volunteers of both genders, aged between 18 and 26. Previous to the study, a bioanalytical method for determination of metformin in human plasma by high performance liquid chromatography with ultraviolet detector (HPLCUV) was validated, and proved to be selective, specific, linear, accurate precise, and therefore, suitable for analysis in plasma. Samples were collected from 0 to 24 hours after the oral administration of a single dose of metformin 850 mg immediate-release coated tablets, produced by Coaspharma S.A. Laboratories. Then, average pharmacokinetic parameters of the twelve volunteers were determined: area under the curve from time zero to last sampling time t (AUC0--->t) 6856.89 ± 2073.8 ng.h/mL, area under the curve from time zero to infinite time (AUC0--->∞) 7083.74 ± 2131.52 ng.h/ml, maximum concentration (Cmax) 1299.02 ± 291.90 ng/mL, maximum time (t max) 2.33 ± 0.47 h, half-life (t1/2) 2.50 ± 0.84 h and apparent elimination constant (Ke) of 0.31 ± 0.12 h-1. These results are similar between the volunteers and no adverse effect was observed. Also, the results are in agree with those reported in literature.