Estudio metagenómico de la microbiota intestinal en pacientes con obesidad mórbida sometidos a cirugía bariátrica

Abstract

Introducción: La cirugía bariátrica (CB) es un tratamiento quirúrgico de la obesidad, cuyo objetivo es lograr el descenso de peso, de masa grasa y alcanzar un impacto metabólico a largo plazo. Se ha observado que ciertos pacientes no responden tan efectivamente a la cirugía, teniendo un descenso de peso inefectivo o recuperando peso tardíamente, y los mecanismos por lo que esto ocurre aún no están bien caracterizados. La microbiota intestinal tiene un rol esencial en varios de los procesos metabólicos asociados a la obesidad. El objetivo de este estudio fue caracterizar el metagenoma intestinal de pacientes candidatos para CB y otros que fueron operados, así como también evaluar las diferencias entre aquellos pacientes que tuvieron un resultado exitoso de la CB y los que no. Material y método: Se extrajo el ADN de 200 mg de heces de pacientes que cumplen criterios de CB, divididos en 3 grupos, basal (preoperatorio), 12 meses y más de 24 meses postoperatorios, con el fin de estudiar y comparar el perfil taxonómico de las comunidades bacterianas de la microbiota intestinal. Resultados: Mientras que la riqueza específica de los grupos de estudio no presentó diferencias significativas, la diversidad beta, que considera las abundancias relativas de los miembros de las comunidades bacterianas estudiadas, evidenció una composición global significativamente diferente entre los grupos de estudio. Sin embargo, nuestro análisis no identificó taxones específicos que pudieran dar explicación a la distinta evolución postoperatoria de los pacientes. Discusión: En la estructura de las comunidades microbianas, se observaron diferencias numéricas entre los grupos en cuanto a la riqueza y abundancia de taxones así como la comparación cuanti y cualitativa. Esta última presentó significativa disimilitud. Los resultados muestran que la principal diferencia entre los grupos de estudio se basó en la abundancia relativa de los gérmenes, cuyo estudio integral podría revelar patrones más consistentes y significativos vinculados a los mecanismos de respuesta terapéutica en sujetos sometidos a CB.

Introduction: Bariatric surgery (BS) is a surgical treatment of obesity, which aims to achieve weight loss, fat mass loss and achieve a long-term metabolic impact. It has been observed that certain patients do not respond as effectively to surgery, having ineffective weight loss or regaining weight late, and the mechanisms by which this occurs are not yet well characterized. The intestinal microbiota plays an essential role in several of the metabolic processes associated with obesity. The objective of our study was to characterize the intestinal metagenome of candidate patients for CB and others who underwent surgery, as well as evaluate the differences between those patients who had a successful outcome from CB and those who did not. Material and method: DNA was extracted from 200 mg of feces from patients who met the criteria for surgical indication, divided into 3 groups, baseline (preoperative), 12 months and more than 24 months postoperatively, in order to analyze and compare the taxonomic profile of the bacterial communities of the intestinal microbiota. Results: While the specific richness of the study groups did not present significant differences, beta diversity, which considers the relative abundances of the members of the bacterial communities studied, showed a significantly different global composition between the study groups. Nevertheless, our study did not identify specific taxa that could explain the different postoperative evolution of the patients. Discussion: In the structure of the microbial communities, numerical differences were observed between the groups in terms of the richness and abundance of taxa as well as the quantitative and qualitative comparison. The latter evidenced significant dissimilarity. The results show that the main difference between the study groups was based on the relative abundance of the germs, whose comprehensive study could reveal more consistent and significant patterns linked to the therapeutic response mechanisms in subjects subjected to CB. ​Bariatric surgery (BS) is a surgical treatment of obesity, whose objective is to achieve weight loss, fat mass and achieve a long-term metabolic impact. However, it has been observed that certain patients do not respond as effectively to surgery, having ineffective weight loss or late weight regain, and the mechanisms by which this occurs are not yet well characterized. The intestinal microbiota plays an essential role in several of the metabolic processes associated with obesity. The aim of this study was to characterize the intestinal metagenome of patients who will and who underwent BS, as well as to assess the differences between those patients who had a successful BS outcome and those who did not. Our results did not identify specific taxa that could explain the different evolution of the patients. While the specific richness of the study groups did not present significant differences, the beta diversity, which considers the relative abundances of the members of the studied bacterial communities, showed a significantly different global composition between the study groups.