Role of Presurgical Gut Microbial Diversity in Roux-en-Y Gastric Bypass Weight-Loss Response: A Cohort Study.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) substantially alters the gut microbial composition which could be associated with the metabolic improvements seen after surgery. Few studies have been conducted in Latin American populations, such as Mexico, where obesity prevalence is above 30% in the adult population. Thus, the aim of this study was to characterize the changes in the gut microbiota structure in a Mexican cohort before and after RYGB and to explore whether surgery-related changes in the microbial community were associated with weight loss. METHODS: Biological samples from patients who underwent RYGB were examined before and 12 months after surgery. Fecal microbiota characterization was performed through 16S rRNA sequencing. RESULTS: Twenty patients who underwent RYGB showed a median excess weight loss of 66.8% 12 months after surgery. Surgery increased alpha diversity estimates (Chao, Shannon index, and observed operational taxonomic units, p < 0.05) and significantly altered gut microbiota composition. Abundance of four genera was significantly increased after surgery: Oscillospira, Veillonella, Streptococcus, and an unclassified genus from Enterobacteriaceae family (PFDR < 0.1). The change in Veillonella abundance was associated with lower excess weight loss (rho = -0.446, p = 0.063) and its abundance post-surgery with a greater BMI (rho = 0.732, p = 5.4 × 10-4). In subjects without type 2 diabetes, lower bacterial richness and diversity before surgery were associated with a greater Veillonella increase after surgery (p < 0.05), suggesting that a lower bacterial richness before surgery could favor the bloom of certain oral-derived bacteria that could negatively impact weight loss. CONCLUSION: Presurgical microbiota profile may favor certain bacterial changes associated with less successful results.

Association of Gut Microbiota with Atherogenic Dyslipidemia, and Its Impact on Serum Lipid Levels after Bariatric Surgery.

Gut microbiota has been suggested to modulate circulating lipids. However, the relationship between the gut microbiota and atherogenic dyslipidemia (AD), defined as the presence of both low HDL-C and hypertriglyceridemia, is not fully understood. Moreover, because obesity is among the main causes of secondary AD, it is important to analyze the effect of gut microbiota composition on lipid profiles after a weight loss intervention. We compared the microbial diversity and taxonomic composition in patients with AD (n = 41) and controls (n = 38) and sought correlations of genera abundance with serum lipid levels in 20 patients after weight loss induced by Roux-en-Y gastric bypass (RYGB) surgery. Gut microbiota composition was profiled using next-generation sequencing of 16S rRNA. Gut microbiota diversity was significantly lower in atherogenic dyslipidemia. Moreover, relative abundance of two genera with LDA score >3.5 (Megasphaera and LPS-producing Escherichia-Shigella), was significantly higher in AD subjects, while the abundance of four short chain fatty acids (SCFA) producing-genera (Christensenellaceae R-7, Ruminococcaceae UCG-014; Akkermansia and [Eubacterium] eligens group) was significantly higher in controls. Notably, [Eubacterium] eligens group abundance was also significantly associated with higher HDL-C levels in RYGB patients one year after surgery. Although dietary polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratio and PUFA intake were higher in controls than in AD subjects, of the four genera differentiated in cases and controls, only Akkermansia abundance showed a positive and significant correlation with PUFA/SFA ratio. Our results suggest that SCFA-producing bacteria promote a healthy lipid homeostasis, while the presence of LPS-producing bacteria such Escherichia-Shigella may contribute to the development of atherogenic dyslipidemia.

Early benefits of bariatric surgery on subclinical cardiac function: Contribution of visceral fat mobilization.

AIMS: We explored the early effects of bariatric surgery on subclinical myocardial function in individuals with severe obesity and preserved left ventricular (LV) ejection fraction. METHODS: Thirty-eight patients with severe obesity [body mass index (BMI) ≥35 kg/m2] and preserved LV ejection fraction (≥50%) who underwent bariatric surgery (biliopancreatic diversion with duodenal switch [BPD-DS]) (Surgery group), 19 patients with severe obesity managed with usual care (Medical group), and 18 age and sex-matched non-obese controls (non-obese group) were included. Left ventricular global longitudinal strain (LV GLS) was evaluated with echocardiography speckle tracking imaging. Abnormal myocardial function was defined as LV GLS <18%. RESULTS: Age of the participants was 42 ±â€¯11 years with a BMI of 48 ±â€¯8 kg/m2 (mean ±â€¯standard deviation); 82% were female. The percentage of total weight loss at 6 months after bariatric surgery was 26.3 ±â€¯5.2%. Proportions of hypertension (61 vs. 30%, P = 0.0005), dyslipidemia (42 vs. 5%, P = 0.0001) and type 2 diabetes (40 vs. 13%, P = 0.002) were reduced postoperatively. Before surgery, patients with obesity displayed abnormal subclinical myocardial function vs. non-obese controls (LV GLS, 16.3 ±â€¯2.5 vs. 19.6 ±â€¯1.7%, P < 0.001). Six months after bariatric surgery, the subclinical myocardial function was comparable to non-obese (LV GLS, 18.2 ±â€¯1.9 vs. 19.6 ±â€¯1.7%, surgery vs. non-obese, P = NS). On the contrary, half of individuals with obesity managed medically worsened their myocardial function during the follow-up (P = 0.002). Improvement in subclinical myocardial function following bariatric surgery was associated with changes in abdominal visceral fat (r = 0.43, P < 0.05) and inflammatory markers (r = 0.45, P < 0.01), whereas no significant association was found with weight loss or change in insulin sensitivity (HOMA-IR) (P > 0.05). In a multivariate model, losing visceral fat mass was independently associated with improved subclinical myocardial function. CONCLUSIONS: Bariatric surgery was associated with significant improvement in the metabolic profile and in subclinical myocardial function. Early improvement in subclinical myocardial function following bariatric surgery was related to a greater mobilization of visceral fat depot, linked to global fat dysfunction and cardiometabolic morbidity.

Continuous glucose monitoring in the management of patients after gastric bypass

Summary: In patients with gastric bypass (GB), high glucose variability (GV) and hypoglycemia have been demonstrated, which could impact the metabolic status and eating behavior. We describe the glucose patterns determined through continuous glucose monitoring (CGM) in two patients with >5 years follow-up after GB and significant weight recovery, who reported hypoglycemic symptoms that interfered with daily activities, and their response to a nutritional and psycho-educative prescription. Case 1: A 40-year-old woman without pre-surgical type 2 diabetes (T2DM) and normal HbA1c, in whom CGM showed high GV and hypoglycemic episodes that did not correlate with the time of hypoglycemic symptoms. Her GV reduced after prescription of a diet with low glycemic index and modification of meal patterns. Case 2: A 48-year-old male with pre-surgical diagnosis of T2DM and current normal HbA1c, reported skipping meals. The CGM showed high GV, 15% of time in hypoglycemia and hyperglycemic spikes. After prescription of a low glycemic index diet, his GV increased and time in hypoglycemia decreased. Through the detailed self-monitoring needed for CGM, we discovered severe anxiety symptoms, consumption of simple carbohydrates and lack of meal structure. He was referred for more intensive psychological counseling. In conclusion, CGM can detect disorders in glucose homeostasis derived both from the mechanisms of bariatric surgery, as well as the patient's behaviors and mental health, improving decision-making during follow-up. Learning Points: High glycemic variability is frequent in patients operated with gastric bypass. Diverse eating patterns, such as prolonged fasting and simple carbohydrate ingestion, and mental health disorders, including anxiety, can promote and be confused with worsened hypoglycemia. CGM requires a detailed record of food ingested that can be accompanied by associated factors (circumstances, eating patterns, emotional symptoms). This allows the detection of particular behaviors and amount of dietary simple carbohydrates to guide recommendations provided within clinical care of these patients.

Differences in Body Composition in Patients with Obesity 1 Year After Roux-En-Y Gastric Bypass: Successful Vs. Unsuccessful Weight Loss.

AIM: The aim of this study is to compare the differences in body composition in patients with obesity with successful weight loss (SWL) and unsuccessful (USWL) 1 year after Roux-en-Y gastric bypass (RYGB). METHODS: We included 36 women and 22 men. After stratifying patients according with SWL (defined as ≥ 50% of excess weight loss), fat-free mass (FFM) and fat mass (FM) trajectories were analyzed in each group. RESULTS: The %FM in SWL women (78%) was lower than USWL (36 vs. 44, p < 0.001). The %FM in SWL men (77%) was lower than USWL (27 vs. 38, p < 0.05). A lower %FM before surgery increased the probability of success (p < 0.05). CONCLUSIONS: SWL patients have a lower %FM, and those with lower pre-surgical %FM are more likely to have SWL 1 year after RYGB.

Effect of bariatric surgery on heart failure.

INTRODUCTION: Obesity increases the risk of heart failure (HF), which continues to be a significant proportion of all cardiovascular diseases and affects increasingly younger populations. The cross-talk between adipose and the heart involves insulin resistance, adipokine signaling and inflammation, with the capacity of adipose tissue to mediate hemodynamic signals, promoting progressive cardiomyopathy. Areas covered: From a therapeutic perspective, there is not yet a single obesity-related pathway that when addressed, can ameliorate cardiomyopathy in obese patients and this is a matter of ongoing research. There is poor evidence of the beneficial long-term effect of small nonsurgical intentional weight loss on HF outcomes, in contrast to the field of HF accompanying severe obesity where observational studies have shown that bariatric surgery is associated with improved cardiac structure/function in severely obese patients with HF and preserved ejection fraction (HFpEF) as well as with improved cardiac structure/function in those with HF and reduced ejection fraction (HFrEF). Few studies report positive outcomes in subjects with obesity and HF, both severe, who underwent bariatric surgery as a rescue treatment, including bridge to heart transplantation. Expert commentary: The fast growing prevalence of obesity will continue to require the development of appropriate interventions directed at controlling or slowing pathways of cardiac damage in these patients, but at present, bariatric surgery should be considered an option to try to decrease morbidity associated with HF in severely obese adults.

Impact of Body Mass Index >50 on Cardiac Structural and Functional Characteristics and Surgical Outcomes After Bariatric Surgery.

BACKGROUND: Body mass index (BMI) ≥50.0 kg/m2 has been associated with increased surgical complications and mortality. We assessed echocardiographic characteristics and bariatric surgery complications of patients with BMI ≥50.0 kg/m2 vs. those in less severe obesity. METHODS AND RESULTS: A retrospective analysis in patients who underwent gastric bypass was performed. Pre-surgery structural characteristics analyzed included left atrial dimension (LA), left ventricle mass (LVM), LVM indexed for height2.7 (LVMI), and LV hypertrophy (LVH). Functional characteristics included LV diastolic and systolic function. Degree of obesity was correlated with cardiac parameters, comorbidities, and surgical complications. Data on 312 patients (75.3 % women, age 39.3 ± 0.6 years, BMI 50.2 ± 0.5 kg/m2) were analyzed. Cardiac parameters on the basis of BMI (<50 kg/m2 vs. ≥50 kg/m2) were LA 39.6 ± 4.8 vs. 41.9 ± 5.2 mm, LVM 161 ± 46 vs. 194 ± 56 g, LVMI 43.6 ± 0.9 vs. 51.8 ± 1.3 g/ht2.7, and systolic pulmonary pressure 43.7 ± 10.1 vs. 50.5 ± 11.3 mmHg, respectively (all p < 0.001). LVMI was correlated with BMI (p < 0.001), 2-h glucose on a glucose tolerance test (p = 0.01), and ejection fraction (p = 0.01). Surgical complications were not different among groups. Presence of LVH was independently associated with BMI ≥50 kg/m2 and female sex, after adjusting for age, diabetes, hypertension, and pulmonary hypertension. CONCLUSION: Body mass index ≥50 kg/m2 was independently associated with female sex and LVH but not with hypertension, diabetes, or a higher rate of surgical complications.

A pathological study of the epidemiology of atherosclerosis in Mexico city.

Objective. To examine the frequency and patterns of association of cardiovascular risk factors with atherosclerosis in five different arterial territories at post-mortem in Mexico City. Methods. We obtained five arterial territories arteries (circle of Willis, coronary, carotid, renal, and aorta) of 185 men and women 0 to 90 years of age who underwent autopsy at the Medical Forensic Service of Mexico City. We determined the prevalence and extent of atherosclerotic lesions by histopathology according to the classification of the American Heart Association as early (types I-III) and advanced (types IV-VI), and according to the degree of stenosis and correlated with cardiovascular risk factors. Results. Atherosclerotic lesions were identified in at least one arterial territory in 181 subjects (97.8%), with involvement of two ore more territories in 178 subjects (92.2%). Advanced lesions were observed in 36% and 67% of subjects under 15 and between 16 and 35 years, respectively. Any degree of atherosclerosis was associated with the presence of diabetes mellitus, hypertension, overweight, obesity, and smoking, and to a greater extent with the presence of two or more risk factors (P < 0.001). However, emerging and advanced athersoclerosis was observed in 53% and 20% people with no risk factors. Conclusions. The study shows a high prevalence of atherosclerosis in all age groups and both sexes. There is considerable development of atherosclerotic disease in subjects without known risk factors.

Prevalence and severity of atherosclerosis in different arterial territories and its relation with obesity.

BACKGROUND: There is uneven association between obesity, traditional risk factors, and cardiovascular events. We aimed to analyze the relation between cardiovascular risk factors, including obesity, with the severity of atherosclerosis in different arterial territories. METHODS: Arteries from five territories (circle of Willis, carotids, coronaries, aorta, and renal) were taken from 185 persons, newborn to 90 years undergoing autopsy in the Forensic Medical Service in Mexico City, to determine atherosclerotic lesions by histopathological study. Lesions were classified according to the American Heart Association grading system as early (types I-III) and advanced (types IV-VI). The degree of atherosclerosis was correlated with arterial territories and risk factors. RESULTS: Frequencies of advanced lesions according to arterial territories were as follows: circle of Willis, 28%; right carotid, 36%; left carotid, 25%; right coronary, 71%; left coronary, 85%; right renal, 26%; left renal, 29%; and aorta, 52%; P=.0001, for all analyses. There was a higher risk for advanced lesions with increasing body mass index (BMI) (P=.004). However, after adjusting for age, gender, smoking status, hypertension, and diabetes mellitus, BMI was not independently associated with advanced lesions. CONCLUSIONS: Coronary arteries are significantly more affected than other arterial territories regardless of risk factors, showing the effect of local and systemic factors in the severity of atherosclerosis. We did not find an independent association between advanced atherosclerotic lesions and obesity.

[The polycystic ovary syndrome. The point of view of the internist]. / Síndrome de ovario poliquístico, el enfoque del internista.

Polycystic ovary syndrome (POS) is a hyperandrogenic state which causes the majority of the fertility and menstrual disorders in premenopausal women. Treatment has focused on gynecologic and endocrine interventions to modify these disorders and the excess androgenic hormone phenotype, which motivates the seeking of treatment for most women. However, there is progressive support for the role of different factors within the disease, such as obesity and insulin resistance. These factors interact with the androgenic hormones and with the ovulatory alterations; but it is yet not known with certainty the fundamental mechanism upon which the disease depends for the manifestation of its symptoms and signs. This association of phenomena has important reflections on the development of cardiovascular diseases. The POS being such a frequent condition, it is often not diagnosed and treated in a multidisciplinary manner. It is important that, apart from looking for improvement in fertility and a decrease of the hyperandrogenic expression, risk factors resulting from this condition are recognized and its treatment include early management of chronic diseases with evidence-based interventions to improve eating and physical activity habits in who, most of the time, are seen to treat other health problems or to improve their reproductive health exclusively.