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.

The Edmonton Obesity Staging System: assessing a potential tool to improve the management of obesity surgery in the Brazilian public health services.

BACKGROUND: Limited access to publicly funded, insurance-covered, and self-paid obesity surgery is a reality worldwide. Waiting lists for procedures are usually based on chronologic criteria and body mass index (BMI)-defined obesity categorization. Obesity classification systems assess overall health and have been proposed as an alternative. OBJECTIVE: To investigate the correlation between BMI-based classification and the Edmonton Obesity Staging System (EOSS) to support current evidence that the assessment of the clinical severity of obesity could be a helpful tool to maximize access to surgery. SETTING: University hospital, Brazil. METHODS: Retrospective analysis of all 2011 to 2014 adult patients who underwent obesity surgery under the public health system. Data on sex, age, presurgical BMI, and co-morbidities were extracted from hospital records. Spearman correlation coefficients were used to assess the strength and direction of the relationship between BMI classification and EOSS. RESULTS: Of 565 patients, 79% were female, mean age 44.1 ± 10.9 years and mean BMI 46.9 ± 6.2 kg/m2. The most common EOSS stage was 2 (86.5%), followed by stages 3 (8.5%) and 1 (4.9%). There was no correlation between the severity of obesity measured by BMI and EOSS (ρ = -.030, P = .475). Older patients had higher Edmonton scores (ρ = .308, P < .001). No difference was observed regarding sex. CONCLUSIONS: No correlation was found between EOSS and BMI and between these and sex. Age correlated with both obesity indicators. EOSS was reproducible in Brazilian surgical patients and may be an important tool from a health services perspective contributing to the more efficient use of limited resources for obesity surgery.

Reduced intestinal FADS1 gene expression and plasma omega-3 fatty acids following Roux-en-Y gastric bypass.

BACKGROUND & AIMS: Roux-en-Y gastric bypass (RYGB) limits food ingestion and may alter the intestinal expression of genes involved in the endogenous synthesis of polyunsaturated fatty acids (PUFAs). These changes may decrease the systemic availability of bioactive PUFAs after RYGB. To study the impact of RYGB on the dietary ingestion and plasma concentration of PUFAs and on the intestinal expression of genes involved in their endogenous biosynthesis in severely obese women with type 2 diabetes. METHODS: Before, and 3 and 12 months after RYGB, obese women (n = 20) self-reported a seven-day dietary record, answered a food frequency query and provided plasma samples for alpha-linolenic (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA) and arachidonic (ARA) acid assessment by gas chromatography. Intestinal biopsies (duodenum, jejunum and ileum) were collected through double-balloon endoscopy before and 3 months after RYGB for gene expression analysis by microarray (Human GeneChip 1.0 ST array) and RT-qPCR validation. RESULTS: Compared to the preoperative period, patients had decreased intakes of PUFAs, fish and soybean oil (p < 0.05) and lower plasma concentrations of ALA and EPA (p < 0.001) 3 and 12 months after RYGB. FADS1 gene expression was lower in duodenum (RT-qPCR fold change = -1.620, p < 0.05) and jejunum (RT-qPCR fold change = -1.549, p < 0.05) 3 months following RYGB, compared to before surgery. CONCLUSION: RYGB decreased PUFA ingestion, plasma ALA and EPA levels, and intestinal expression of FADS1 gene. The latter encodes a key enzyme involved in endogenous biosynthesis of PUFAs. These data suggest that supplementation of omega-3 PUFAs may be required for obese patients undergoing RYGB. Clinical Trial Registry number and website: www.clinicaltrials.gov - NCT01251016; Plataforma Brasil - 19339913.0.0000.0068.