Roux-en-Y Gastric Bypass Surgery Induces Distinct but Frequently Transient Effects on Acylcarnitine, Bile Acid and Phospholipid Levels

H OH OH metabolites Article Roux-en-Y Gastric Bypass Surgery Induces Distinct but Frequently Transient Effects on Acylcarnitine, Bile Acid and Phospholipid Levels Jarlei Fiamoncini 1,2,† , Carina Fernandes Barbosa 3,† , José Rubens Arnoni Junior 3 , José Celestino Araújo Junior 3 , Cinthia Taglieri 3 , Tiago Szego 4 , Barbara Gelhaus 2 , Heraldo Possolo de Souza 5 , Hannelore Daniel 2 and Thais Martins de Lima 5, * 1 2 3 4 5 * † Department of Food Science and Experimental Nutrition, School of Pharmaceutical Sciences, University of São Paulo, 05508-060 São Paulo, Brazil; Nutrition and Food Sciences, Technische Universität München, 85354 Freising-Weihenstephan, Germany; (B.G.); (H.D.) Clinica IMEC, Sao Paulo, 04260-020 São Paulo, Brazil; (C.F.B.); (J.R.A.J.); (J.C.A.J.); (C.T.) Instituto CIGO, 05508-060 São Paulo, Brazil; Laboratório de Emergências Clínicas (LIM 51), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, 05508-060 São Paulo, Brazil; Correspondence: ; Tel.: +55-11-3061-8480 These authors contributed equally to this work. Received: 3 October 2018; Accepted: 17 November 2018; Published: 23 November 2018



 Abstract: Roux-en-Y gastric bypass (RYGB) is an effective method to achieve sustained weight loss, but the mechanisms responsible for RYGB effects have not yet been fully characterized. In this study, we profiled the concentrations of 143 lipid metabolites in dry blood spots (DBS) of RYGB patients. DBS from obese patients (BMI range 35–44 kg/m2 ) were collected 7 days before, 15 and 90 days after the surgery. LC-MS/MS was used to quantify acylcarnitines, phosphatidylcholines, sphingomyelins and bile acids. RYGB caused a rapid increase in acylcarnitine levels that proved to be only transient, contrasting with the sustained decrease in phosphatidylcholines and increase of sphingomyelins and bile acids. A PLS-DA analysis revealed a 3-component model (R2 = 0.9, Q2 = 0.74) with key metabolites responsible for the overall metabolite differences. These included the BCAA-derived acylcarnitines and sphingomyelins with 16 and 18 carbons. We found important correlations between the levels of BCAA-derived acylcarnitines and specific sphingomyelins with plasma cholesterol and triacylglycerol concentrations. Along with the marked weight loss and clinical improvements, RYGB induced specific alterations in plasma acylcarnitines, bile acid and phospholipid levels. This calls for more studies on RYGB effects aiming to elucidate the metabolic adaptations that follow this procedure. Keywords: obesity; bariatric surgery; acylcarnitine; bile acids; phospholipids; metabolomics 1. Introduction Obesity represents a major health challenge, whose main consequence is the increase in the prevalence of metabolic diseases such as metabolic syndrome, type 2 diabetes, cardiovascular diseases, hepatic steatosis, and different types of cancer [1]. Obesity and the comorbidities pose a huge burden for health systems demanding efficient treatment options [2]. Bariatric surgery is the most efficient therapy against obesity, with four dominant surgical procedures: biliopancreatic diversion, roux-en-Y gastric bypass (RYGB), adjustable gastric banding and sleeve gastrectomy, ranging from malabsorptive to completely restrictive [3]. The procedures induce Metabolites 2018, 8, 83; doi:10.3390/metabo8040083 www.mdpi.com/journal/metabolites Metabolites 2018, 8, 83 2 of 17 effects beyond body weight reduction, including resolution or improvement of comorbidities such as diabetes, hypertension, hyperlipidemia and sleep apnea [3]. Bariatric surgery techniques produce significant improvements in serum lipids, but changes vary due to anatomic alterations distinct to each procedure. The RYGB leads to major improvements in blood glucose and insulin concentrations, hormonal responses, as well as decreased inflammatory markers [4,5]. Alterations in the secretion of gastric and intestinal peptides, such as glucagon-like peptide-1 (GLP-1), ghrelin and YY peptide were demonstrated after RYGB [6,7]. Lipid metabolism is also modified after surgery with decreased levels of total cholesterol and LDL-cholesterol, and increase in HDL-cholesterol [8]. Despite these effects in metabolic markers, the underlying mechanisms responsible for the observed changes remain to be defined. The application of metabolomics and the possibility of profiling a large number of metabolites derived from different pathways provides new insights into metabolic interdependencies. As examples, metabolomics applications revealed the relationship between obesity and plasma branched-chain amino acids (BCAA) concentrations [9] and the association between plasma phospholipids with diabetes [10,11]. Although altered plasma lipid profiles have been related to obesity comorbidities such as diabetes, atherosclerosis and NAFLD, only a few studies have focused on the lipidome of patients undergoing RYGB [11–14]. In this study, changes in plasma lipid subclasses represented by acylcarnitines, phosphatidylcholines, sphingomyelins and bile acids were assessed before and after RYGB. We revealed important correlations between different lipid species and the major outcomes of the RYGB, with new insights into the metabolic changes after the surgery. Our approach involved the use of dried blood spots (DBS) to sample blood for metabolomics analysis. This practical sampling approach produced reliable data, similar to what have been previously described. Besides providing more insights into the mechanisms involved in RYGB effects on metabolism, this study also validates DBS as a sampling technique for clinical studies. 2. Material and Methods 2.1. Study Cohort and Sample Collection Thirty-nine morbidly obese patients (14 male and 25 female subjects) as candidates for RYGB Surgery were recruited at Clinica IMEC (São Paulo, Brazil). All subjects gave written informed consent. Local ethics committee approved the clinical investigation (Protocol Number: 31498414.3.0000.0068). Exclusion criteria included patients younger than 18 or older than 60 years; patients with hepatopathies, pancreatopathies, inflammatory bowel disease, cancer, chronic diarrhea, unbalanced constipation (in regular use of laxatives), enterorrhagia; patients undergoing previous gastrointestinal surgeries. After the surgery, there was a drop out of 13 volunteers, leaving only 26 patients 15 and 90 days after surgery (7 males and 19 females). Table 1 presents the medication taken by some of the participants. Around 50% of the volunteers did not use any medication and only 2 patients took more than 2 different medications. Dried blood spots (DBS) samples were collected after a 12-hours fasting 7 days before, 15 and 90 days after surgery by puncturing the tip of the patients’ finger with a sterile lancet on a blood collection filter paper for metabolomics analysis (903 Protein Saver, Whatman). Fasting plasma samples for clinical chemistry (...truncated)