Roux-en-Y gastric bypass affects the expression of genes related to the intestinal folate metabolism pathway in obese women.

OBJECTIVES: Roux-en-Y gastric bypass (RYGB) promotes sustained weight loss, and the resulting new gastrointestinal anatomy can contribute to nutritional depletions. Folate deficiency is one of the most frequently observed nutritional deficiencies after RYGB. The aim of this study was to assess whether RYGB affects the expression of genes related to the intestinal folate metabolism pathway as an additional molecular mechanism contributing to its postoperative deficiency. METHODS: Biopsies from the duodenum, jejunum, and ileum of 20 obese women were collected before and 3 mo after RYGB. The expression of genes involved in intestinal folate metabolism was assessed by microarray and reverse transcriptase polymerase chain reaction (RT-qPCR). Folate intake (7-d food record) and plasma levels (electrochemiluminescence) also were measured. RESULTS: Compared with the preoperative phase, transcriptomic alterations were observed in all intestinal segments studied after RYBG, mainly marked by decreased expression of genes encoding folate transporters/receptors and increased expression of genes involved in folate biosynthesis (P < 0.05). Reduced folate intake and plasma folate levels were also observed simultaneously (P < 0.05). Plasma folate concentrations correlated inversely with intestinal FOLR2 and SHMT2 genes (P < 0.001). CONCLUSION: The present findings suggested that impaired expression of genes related to intestinal folate metabolism may contribute to the early systemic deficiency after RYGB and highlight a potential transcriptomic reprogramming of the intestine in response to RYGB to compensate for folate depletion induced by this surgical technique.

Gastrointestinal genetic reprogramming of vitamin A metabolic pathways in response of Roux-en-Y gastric bypass.

Roux-en-Y gastric bypass (RYGB) is one of the most performed bariatric surgical techniques. However, RYGB commonly results, as side effects, in nutritional deficiencies. This study aimed to examine changes in the expression of vitamin A pathway encoding genes in the gastrointestinal tract (GI) and to evaluate the potential mechanisms associated with hypovitaminosis A after RYGB. Intestinal biopsies were obtained through double-balloon endoscopy in 20 women with obesity (age 46.9±6.2 years; body mass index [BMI] 46.5±5.3 kg/m2 [mean±SD]) before and three months after RYGB (BMI, 38.2±4.2 kg/m2). Intestinal mucosal gene microarray analyses were performed in samples using a Human GeneChip 1.0 ST array (Affymetrix). Vitamin A intake was assessed from 7-day food records and serum retinol levels were evaluated by electrochemiluminescence immunoassay. Our results showed the following genes with significant downregulation (p≤0.05): LIPF (-0.60), NPC1L1 (-0.71), BCO1 (-0.45), and RBP4 (-0.13) in duodenum; CD36 (-0.33), and ISX (-0.43) in jejunum and BCO1 (-0.29) in ileum. No significant changes in vitamin A intake were found (784±694 retinol equivalents [RE] pre-operative vs. 809±753 RE post-operative [mean±SD]). Although patients were routinely supplemented with 3500 international units IU/day (equivalent to 1050 µg RE/day) of oral retinol palmitate, serum concentrations were lower in the post-operative when compared to pre-operative period (0.35±0.14 µg/L vs. 0.52±0.33 µg/L, respectively - P=0.07), both within the normal range. After RYGB, the simultaneous change in expression of GI genes, may impair carotenoid metabolism in the enterocytes, formation of nascent chylomicrons and transport of retinol, resulting in lower availability of vitamin A.

Nutritional guidance, monitoring, and supplementation before and after bariatric surgery - Are we doing this correctly?

INTRODUCTION: Background and aims: minimizing nutritional depletions after a Roux-en-Y gastric bypass (RYGB) may improve clinical results in the treatment of obesity. We evaluated nutritional aspects of obese women undergoing RYGB at a reference university hospital with a department specialized in bariatric surgery. Method: based on the Dietary Reference Intakes developed by the Food and Nutrition Council, Institute of Medicine, and the guidelines issued by the American Society for Metabolic and Bariatric Surgery, we assessed the quantitative and qualitative adequacy of nutritional intake, supplementation, and biochemical monitoring of 20 women both before and 3 and 12 months after a RYGB. Data on nutritional intake was obtained by applying different food surveys, quantitatively interpreted by the Virtual Nutri Plus® software and using reference nutritional databases. Results: nutritional intake deficits were already found before the RYGB (p ≤ 0.05). These worsened postoperatively (p ≤ 0.05), a period also marked by a qualitatively poor diet. The nutritional supplementation prescribed did not fully achieve the reference recommendations, and was poorly complied with by patients. Furthermore, nutritional monitoring was not carried out in all patients, recommended biochemical markers were not screened, and vitamin D depletions occurred. Conclusion: our data suggest that institutions specialized in bariatric patient care may not be adequately adhering to well known guidelines, or applying efficient strategies to improve compliance.

INTRODUCCIÓN: Antecedentes y objetivos: minimizar el deterioro nutricional después del baipás gástrico en Y de Roux (BGYR) puede mejorar los resultados clínicos en el tratamiento de la obesidad. Se evaluaron aspectos nutricionales de mujeres obesas sometidas a BGYR en un hospital universitario de referencia con servicio especializado de cirugía bariátrica. Método: con base en la Ingesta Dietética de Referencia desarrollada por el Consejo de Alimentos y Nutrición del Instituto de Medicina, y las directrices de la Sociedad Estadounidense de Cirugía Bariátrica y Metabólica, evaluamos la adecuación cuantitativa y cualitativa de la ingesta nutricional, la suplementación y el seguimiento bioquímico de 20 mujeres tanto antes como 3 y 12 meses después de un BGYR. Los datos de la ingesta nutricional se obtuvieron mediante la aplicación de diferentes encuestas alimentarias, interpretadas cuantitativamente por el software Virtual Nutri Plus® y utilizando bases de datos nutricionales de referencia. Resultados: se encontraron déficits de ingesta nutricional antes del BGYR (p < 0,05). Estos empeoraron en el postoperatorio (p < 0,05), período también marcado por una mala alimentación cualitativa. La suplementación nutricional prescrita no cumplió plenamente con las recomendaciones de referencia y no fue bien cumplida por los pacientes. Además, la monitorización nutricional no se aplicó en todos los pacientes y no se examinaron todos los marcadores bioquímicos recomendados, hallándose depleciones de vitamina D. Conclusión: nuestros datos sugieren que las instituciones especializadas en la atención de pacientes bariátricos podrían no estar siguiendo adecuadamente las pautas recomendadas, ni aplicando estrategias eficientes para mejorar su cumplimiento.