Ismael Francisco Mota Siqueira Guarda

Gastrointestinal Transcriptomic Response of Metabolic Vitamin B12 Pathways in Roux-en-Y Gastric Bypass

OBJECTIVES: Vitamin B12 (B12) deficiency after Roux‐en‐Y gastric bypass (RYGB) is highly prevalent and may contribute to postoperative complications. Decreased production of intrinsic factor owing to gastric fundus removal is thought to have a major role, but other components of B12 metabolism may also be affected. We evaluated changes in the expression levels of multiple B12 pathway‐encoding genes in gastrointestinal (GI) tissues to evaluate the potential roles in contributing to post‐RYGB B12 deficiency. METHODS: During double‐balloon enteroscopy, serial GI biopsies were collected from 20 obese women (age, 46.9±6.2 years; body mass index, 46.5±5.3 kg/m2) with adult‐onset type 2 diabetes (fasting plasma glucose ≥126 mg/dl; hemoglobin A1c≥6.5%) before and, at the same site, 3 months after RYGB. Gene expression levels were assessed by the Affymetrix Human GeneChip 1.0 ST microarray. Findings were validated by real‐time quantitative PCR (RT–qPCR). RESULTS: Gene expression levels with significant changes (P≤0.05) included: transcobalamin I (TCN1) in remnant (−1.914‐fold) and excluded (−1.985‐fold) gastric regions; gastric intrinsic factor (GIF) in duodenum (−0.725‐fold); and cubilin (CUBN) in duodenum (+0.982‐fold), jejunum (+1.311‐fold), and ileum (+0.685‐fold). Validation by RT–qPCR confirmed (P≤0.05) observed changes for TCN1 in the remnant gastric region (−0.132‐fold) and CUBN in jejunum (+2.833‐fold). CONCLUSIONS: RYGB affects multiple pathway‐encoding genes that may be associated with postoperative B12 deficiency. Decreased TCN1 levels seem to be the main contributing factor. Increased CUBN levels suggest an adaptive genetic reprogramming of intestinal tissue aiming to compensate for impaired intestinal B12 delivery.

The SURMetaGIT study: Design and rationale for a prospective pan-omics examination of the gastrointestinal response to Roux-en-Y gastric bypass surgery

Objective To describe the protocol of the SURgically induced Metabolic effects on the Human GastroIntestinal Tract (SURMetaGIT) study, a clinical pan-omics study exploring the gastrointestinal tract as a central organ driving remission of type 2 diabetes mellitus (T2DM) after Roux-en-Y gastric bypass (RYGB). The main points considered in the study’s design and challenges faced in its application are detailed. Methods This observational, longitudinal, prospective study involved collection of gastrointestinal biopsy specimens, faeces, urine, and blood from 25 obese women with T2DM who were candidates for RYGB (20 patients for omics assessment and 5 for omics validation). These collections were performed preoperatively and 3 and 24 months postoperatively. Gastrointestinal transcriptomics; faecal metagenomics and metabolomics; plasma proteomics, lipidomics, and metabolomics; and biochemical, nutritional, and metabolic data were assessed to identify their short- and long-term correlations with T2DM remission. Results Data were collected from 20 patients before and 3 months after RYGB. These patients have nearly completed the 2-year follow-up assessments. The five additional patients are currently being selected for omics data validation. Conclusion The multi-integrated pan-omics approach of the SURMetaGIT study enables integrated analysis of data that will contribute to the understanding of molecular mechanisms involved in T2DM remission after RYGB.

Effects of ethyl pyruvate on leukocyte-endothelial interactions in the mesenteric microcirculation during early sepsis treatment.

OBJECTIVES: Experimental studies on sepsis have demonstrated that ethyl pyruvate is endowed with antioxidant and anti-inflammatory properties. This study aimed to investigate the effects of ethyl pyruvate on leukocyte-endothelial interactions in the mesenteric microcirculation in a live Escherichia coli-induced sepsis model in rats. METHODS: Male Wistar rats were administered an intravenous suspension of E. coli bacteria or were subjected to a sham procedure. Three hours after bacterial infusion, the rats were randomized into the following groups: a control group without treatment, a group treated with lactated Ringers solution (4 mL/kg, i.v.), and a group treated with lactated Ringers solution (4 mL/kg, i.v.) plus ethyl pyruvate (50 mg/kg). At 24 h after bacterial infusion, leukocyte-endothelial interactions were investigated using intravital microscopy, and the expression of P-selectin and intercellular adhesion molecule-1 was evaluated via immunohistochemistry. White blood cell and platelet counts were also determined at baseline and 3 h and 24 h after E. coli inoculation. RESULTS: The non-treated and lactated Ringers solution-treated groups exhibited increases in the numbers of rolling leukocytes (∼2.5-fold increase), adherent cells (∼3.0-fold), and migrated cells (∼3.5-fold) compared with the sham group. In contrast, treatment with Ringers ethyl pyruvate solution reduced the numbers of rolling, adherent and migrated leukocytes to the levels observed in the sham group. Additionally, the expression of P-selectin and intercellular adhesion molecule-1 was significantly increased on mesenteric microvessels in the non-treated group compared with the sham group (p<0.001). The expression of both adhesion molecules was reduced in the other groups, with ethyl pyruvate being more effective than lactated Ringers solution. Infusion of bacteria caused significant leukopenia (3 h), followed by leukocytosis with granulocytosis (24 h). There was also an intense and progressive reduction in the number of platelets. However, no differences were observed after treatment with the different solutions. CONCLUSIONS: The presented data suggest that ethyl pyruvate efficiently reduces the inflammatory response in the mesenteric microcirculation in an experimental model of sepsis induced by live E. coli and is associated, at least in part, with down-regulation of P-selectin and intercellular adhesion molecule-1.