Fat-Free Mass and Skeletal Muscle Mass Five Years After Bariatric Surgery

Circulating myostatin as a biomarker of muscle mass and strength in individuals with cancer or obesity

BACKGROUND & AIMS

Our study aims to determine whether myostatin (MSTN) is associated with muscle mass and strength in individuals with cancer or obesity, as well as with cancer cachexia (CC) or sarcopenic obesity (SO).

METHODS

The ACTICA study included individuals with CC (n = 70) or without CC (NC, n = 73). The MYDIASECRET study included individuals with obesity evaluated before (T0) and 3 months (T3) after bariatric surgery (n = 62). Body composition was assessed using bioelectrical impedance analysis (BIA). Skeletal muscle mass (SMM) and appendicular SMM (ASMM) were calculated from Janssen's and Sergi's equations, respectively, and expressed as indexes (SMMI and ASMMI). Handgrip strength (HGS) was assessed using a Jamar hand-held dynamometer. MSTN plasma levels were measured using ELISA. Spearman's coefficient was used to correlate MSTN with muscle mass and strength. Receiver operating characteristic (ROC) curve analysis was performed to identify an optimal MSTN cutoff level for the prediction of CC or SO.

RESULTS

In the ACTICA study, muscle mass and strength were lower in CC individuals than in NC individuals (SMMI: 8.0 kg/m2vs 9.0 kg/m2, p = 0.004; ASMMI: 6.2 kg/m2vs 7.2 kg/m2, p < 0.001; HGS: 28 kg vs 38 kg, p < 0.001). MSTN was also lower in CC individuals than in NC individuals (1434 pg/mL vs 2149 pg/mL, p < 0.001). Muscle mass and strength were positively correlated with MSTN (SMMI: R = 0.500, p < 0.001; ASMMI: R = 0.479, p < 0.001; HGS: R = 0.495, p < 0.001). ROC curve analysis showed a MSTN cutoff level of 1548 pg/mL (AUC 0.684, sensitivity 57%, specificity 75%, p < 0.001) for the prediction of CC. In the MYDIASECRET study, muscle mass and strength were reduced at T3 (SMMI: -8%, p < 0.001; ASMMI: -12%, p < 0.001; HGS: -6%, p = 0.005). MSTN was also reduced at T3 (1773 pg/mL vs 2582 pg/mL, p < 0.001). Muscle mass and strength were positively correlated with MSTN at T0 and T3 (SMMI-T0: R = 0.388, p = 0.002; SMMI-T3: R = 0.435, p < 0.001; HGS-T0: R = 0.337, p = 0.007; HGS-T3: R = 0.313, p = 0.013). ROC curve analysis showed a MSTN cutoff level of 4225 pg/mL (AUC 0.835, sensitivity 98%, specificity 100%, p = 0.014) for the prediction of SO at T3.

CONCLUSIONS

MSTN is positively correlated with muscle mass and strength in individuals with cancer or obesity, suggesting its potential use as a biomarker of muscle mass and strength. The ROC curve analysis suggests the potential use of MSTN as a screening tool for CC and SO.

Changes in renal blood flow after surgically induced weight loss: can bariatric surgery halt the progression of chronic kidney disease?

BACKGROUND

We previously demonstrated how kidney injury in patients with morbid obesity can be reversed by bariatric surgery (BaS).

OBJECTIVE(S)

Based on previous experience, we hypothesize patients' potentially reversible kidney injury might be secondary to reduction in renal blood flow (RBF), which improves following BaS.

SETTING

Academic Hospital.

METHODS

We conducted a retrospective analysis of patients who underwent BaS at our institution from 2002 to 2019. We identified patients with chronic kidney disease (CKD) using the estimated glomerular filtration rate (eGFR) from the CKD Epidemiology Collaboration Study (CKD-EPI) classification system. We used the BUN/Creatinine (Cr) ratio pre- and postoperatively to determine a prerenal (decreased RBF) versus intrinsic component as the responsible cause of CKD in this patient population. Decreased RBF was defined as BUN/Cr > 20 preoperatively.

RESULTS

Our analysis included n = 2924 patients, of which 11% (n = 325) presented decreased RBF. From our original sample, only n = 228 patients had the complete data necessary to assess both eGFR and RBF (BUN/Cr). Patients with baseline CKD stage 2 demonstrated preoperative BUN/Cr 20.85 ± 10.23 decreasing to 14.99 ± 9.10 at 12-month follow-up (P < .01). Patients with baseline CKD stage 3 presented with preoperative BUN/Cr 23.88 ± 8.75; after 12-month follow-up, BUN/Cr ratio decreased to 16.38 ± 9.27 (P < .01). Patients with CKD stage 4 and ESRD (eGFR < 30) did not demonstrate a difference for pre- and postoperative BUN/Cr 21.71 ± 9.28 and 19.21 ± 14.58, respectively.

CONCLUSION(S)

According to our findings, patients with CKD stages 1-3 present improvement of their kidney function after BaS. This amelioration could be secondary to improvement of the RBF, an unstudied reversible mechanism of kidney injury in the bariatric population.

Resistance Training in Patients After Metabolic and Bariatric Surgery: Protocol for a Systematic Review

BACKGROUND

Resistance training has been consistently shown to have multiple health benefits, especially for patients who have undergone bariatric surgery. Patients who have undergone bariatric surgery are recommended to participate in resistance exercise; however, protocols and guidelines for resistance training remain poorly implemented.

OBJECTIVE

This is a protocol for a systematic review and possibly a meta-analysis that will synthesize evidence of the effects of resistance exercise on changes in body composition, muscular strength, overall weight loss or maintenance of weight loss, and quality of life in patients after metabolic and bariatric surgery (MBS). The findings of this study may provide practice recommendations for resistance training among patients who have undergone MBS.

METHODS

We registered this systematic review on PROSPERO (CRD42023464928) on September 18, 2023. A systematic search of electronic databases (Embase, PubMed, Scopus, Web of Science, and CINAHL) was conducted on studies published from January 1, 1991, to May 15, 2023, to identify English-language human studies on adult patients who have undergone MBS that include a resistance training intervention and describe outcome measurements of body composition or strength. Screening will be performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and relevant data elements will be extracted.

RESULTS

Searches and screenings commenced in May 2023. Data extraction and analyses will be completed by the end of December 2023, after which findings will be synthesized and reported by the end of March 2024.

CONCLUSIONS

This systematic review will summarize the evidence regarding resistance training in patients after MBS. The findings from this systematic review and possible meta-analysis may provide practice recommendations for resistance training protocols in this patient population and identify characteristics of protocols with the best adherence and outcomes. With these results, we anticipate that we will gain a deeper understanding of the role of resistance training after MBS.

TRIAL REGISTRATION

PROSPERO CRD42023464928; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=464928.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/49513.

Effects of a supervised exercise training on body composition after bariatric surgery: a randomized controlled trial

OBJECTIVE

This study aimed to determine the effects of a multicomponent exercise intervention during the first year post-bariatric surgery (BS) on body composition, weight loss (WL), energy expenditure, and nutrient intake.

METHODS

A total of 84 patients were included in this study and were randomly assigned to either an exercise group (n = 41) or a control group (n = 20). The exercise group participated in a multicomponent exercise program that began 1-month post-BS, whereas the control group received only standard medical care post-BS. Body composition was assessed by dual-energy x-ray absorptiometry, and physical activity energy expenditure was assessed by accelerometers. Nutritional intake was assessed through a 4-day food diary.

RESULTS

A total of 6-months post-BS, exercise was found to be effective in mitigating the loss of lower-limb and appendicular lean mass (LM), as well as favoring trunk fat mass (FM) loss. Moreover, it further decreased percent FM and promoted additional excess WL. After 12 months, exercise not only reduced waist circumference but also helped to lessen the loss of total, trunk, and appendicular LM.

CONCLUSIONS

Exercise further induced trunk fat mass, percent FM, excess WL, and waist circumference reductions. Moreover, exercise attenuated the loss of total and regional LM.

Identification of myokines susceptible to improve glucose homeostasis after bariatric surgery

IMPORTANCE AND OBJECTIVE

The identification of myokines susceptible to improve glucose homeostasis following bariatric surgery could lead to new therapeutic approaches for type 2 diabetes.

METHODS

Changes in the homeostasis model assessment (HOMA) test were assessed in patients before and 3 months after bariatric surgery. Changes in myokines expression and circulating levels were assessed using real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Myokines known to regulate glucose homeostasis were identified using literature (targeted study) and putative myokines using RNA-sequencing (untargeted study). A linear regression analysis adjusted for age and sex was used to search for associations between changes in the HOMA test and changes in myokines.

RESULTS

In the targeted study, brain-derived neurotrophic factor (BDNF) expression was upregulated (+30%, P = .006) while BDNF circulating levels were decreased (-12%, P = .001). Upregulated BDNF expression was associated with decreased HOMA of insulin resistance (HOMA-IR) (adjusted estimate [95% confidence interval {CI}]: -0.51 [-0.88 to -0.13], P = .010). Decreased BDNF serum levels were associated with decreased HOMA of beta-cell function (HOMA-B) (adjusted estimate [95% CI] = 0.002 [0.00002-0.0031], P = .046). In the untargeted study, upregulated putative myokines included XYLT1 (+64%, P < .001), LGR5 (+57, P< .001), and SPINK5 (+46%, P < .001). Upregulated LGR5 was associated with decreased HOMA-IR (adjusted estimate [95% CI] = -0.50 [-0.86 to -0.13], P = .009). Upregulated XYLT1 and SPINK5 were associated with increased HOMA of insulin sensitivity (HOMA-S) (respectively, adjusted estimate [95% CI] = 109.1 [28.5-189.8], P = .009 and 16.5 [0.87-32.19], P = .039).

CONCLUSIONS

Improved glucose homeostasis following bariatric surgery is associated with changes in myokines expression and circulating levels. In particular, upregulation of BDNF, XYLT1, SPINK5, and LGR5 is associated with improved insulin sensitivity. These results suggest that these myokines could contribute to improved glucose homeostasis following bariatric surgery.

STUDY REGISTRATION

NCT03341793 on ClinicalTrials.gov (https://clinicaltrials.gov/).

Brazilian guide to nutrition in bariatric and metabolic surgery

PURPOSE

Brazilian nutrition recommendations for bariatric and metabolic surgery aim to provide knowledge, based on scientific evidence, on nutritional practices related to different surgical techniques in the surgical treatment of obesity and metabolic diseases.

MATERIALS AND METHODS

A systematic literature search was carried out with the appropriate MeSH terms using Medline/Pubmed/LiLACS and the Cochrane database, with the established criteria being based on the inclusion of articles according to the degree of recommendation and strength of evidence of the Classification of Recommendations, Evaluation, Development, and Evaluation System (GRADE).

RESULTS

The recommendations that make up this guide were gathered to assist in the individualized clinical practice of nutritionists in the nutritional management of patients with obesity, including nutritional management in the intragastric balloon; pre and postoperative nutritional treatment and supplementation in bariatric and metabolic surgeries (adolescents, adults, elderly, pregnant women, and vegetarians); hypoglycemia and reactive hyperinsulinemia; and recurrence of obesity, gut microbiota, and inflammatory bowel diseases.

CONCLUSION

We believe that this guide of recommendations will play a decisive role in the clinical practice of nutritionists who work in bariatric and metabolic surgery, with its implementation in health services, thus promoting quality and safety in the treatment of patients with obesity. The concept of precision nutrition is expected to change the way we understand and treat these patients.

Usual dietary intake, physical activity, weight loss, and body composition after five years of Roux-en-Y gastric bypass

OBJECTIVE

To estimate usual dietary intake (UDI), physical activity (PA), and their association with weight loss and body composition in patients who underwent Roux-en-Y gastric bypass (RYGB) after five years in the Federal District, Brazil.

METHODS

We assessed anthropometry and body composition using bioimpedance, and dietary intake and PA with three nonconsecutive 24-h recalls. PC-Side was used to estimate UDI. Dietary patterns (DPs) were identified through principal component analysis, and association between UDI and PA with percentage of total weight loss (%TWL) and fat-free mass (FFM) through multinomial logistic regression.

RESULTS

Sample (n = 124) presented mean (SD) age of 48.9 (9.4) years, median (IQR) of 9 years (7-10) post RYGB, current BMI = 32.3 kg/m² (28.8-35.7), %TWL = 24.7% (10.9), and FFM = 45.1 kg (41.1-51.9). Mean usual energy intake of 1556 kcal/d, with adequate protein intake, poor fiber intake, and excessive carbohydrate, total fat, and added sugar intake, compared to dietary guidelines. Calcium, vitamins C, D, and E presented the greatest inadequacy (15%, 24%, 32%, and 49% of individuals, respectively, reported usual intake below EAR); 83 participants were considered active/very active, according PA. DP with high energy, protein, total fat, saturated fat, and sodium intake, was negatively associated with %TWL (OR = 0.545, p = 0.037). Protein intake was positively associated with FFM (OR = 1.091, p = 0.004). PA was not associated with %TWL or FFM.

CONCLUSION

Participants demonstrated intake of carbohydrate, fat, fiber, added sugar not in accordance with guidelines. A DP rich in energy, protein, total fat, saturated fat, and sodium appears to decrease TWL. However, protein intake appears to increase FFM.

Marked weight loss on liraglutide 3.0 mg: Real-life experience of a Swiss cohort with obesity

OBJECTIVE

This study investigated the effectiveness of liraglutide 3.0 mg daily in combination with a standardized multidisciplinary intervention on body weight and body composition changes in a real-life setting.

METHODS

A prospective, observational cohort study design was used. Adult patients with BMI > 35 kg/m² , or BMI > 28 kg/m² with greater than or equal to one metabolic comorbidity, were included (n = 54, 65% women). Liraglutide treatment was covered by Swiss health insurance. Clinical and biological data were collected at baseline, 4 months, and 10 months. Body composition was assessed by dual-energy x-ray absorptiometry at baseline and 10 months.

RESULTS

At 10 months, mean (SD) percentage weight loss (WL%) was -12.4% (5.5%) or -14.1 (6.6) kg. WL% was ≥5% in 87% of patients at 4 months and in 96% at 10 months. WL% was higher in women (-9.5% [3.1%] vs. men -7.2% [2.5%], p = 0.02) at 4 months and persisted at 10 months (-13.7% [5.2%] vs. -9.6% [5.1%], p = 0.006). WL% was associated with baseline percentage fat mass but not with age or BMI. Body composition showed a decrease in fat mass, visceral adipose tissue, and absolute lean mass.

CONCLUSIONS

In a real-world setting, liraglutide 3.0 mg led to beneficial changes in WL and body composition, with a greater impact in women.

Phase angle (PhA) in overweight and obesity: evidence of applicability from diagnosis to weight changes in obesity treatment

Phase angle (PhA) is a recently proposed marker of nutritional status in many clinical conditions. Its use in patients with obesity presents different critical concerns due to the higher variability of the two measured parameters (resistance, R, and reactance, Xc) that contribute to the determination of PhA. Controversial is the relation between PhA and BMI that might vary with graded levels of obesity due to the variation in fat and free fat mass. Obesity is frequently associated with metabolic, hepatic, cardiovascular and kidney diseases that introduce variations in PhA values, in relation to multimorbidity and severity degree of these diseases. It is reported that the improvement of clinical condition is associated with a positive change in PhA. Also, the treatment of obesity with weight loss might confirm this effect, but with different responses in relation to the type and duration of the intervention applied. In fact, the effect appears not only related to the percentage of weight loss but also the possible loss of free fat mass and the nutritional, metabolic and structural modifications that might follow each therapeutic approach to decrease body weight. We can conclude that the PhA could be used as marker of health status in patients with obesity supporting an appropriate weight loss intervention to monitor efficacy and fat free mass preservation.

Magnetic Resonance Imaging to Assess Body Composition Change in Adolescents With Obesity After Sleeve Gastrectomy

OBJECTIVES

Metabolic and bariatric surgery is the most effective weight loss treatment for severe obesity. The number of adolescents undergoing sleeve gastrectomy is increasing. We investigated changes in body composition in adolescents undergoing sleeve gastrectomy 12-26 weeks post-operatively using whole-body magnetic resonance imaging (WB-MRI).

METHODS

This prospective cohort study assessed changes in adipose tissue compartments (ie, visceral, subcutaneous, and intermuscular) and muscle in 18 obese adolescents, ages 14-19, 89% female, with body mass index z -score of 2.6 ± 0.25 (range 2.16-3.2). All underwent WB-MRI 1.5-17 weeks pre-operatively and 12-26 weeks post-operatively.

RESULTS

Pre- and post-operative WB-MRI showed decreases in all adipose tissue compartments, as well as decreased skeletal muscle and liver fat fraction ( P < 0.0001). The post-operative percentage loss of adipose tissue in subcutaneous, visceral, and intermuscular compartments (89.0%, 5.8%, 5.2%, respectively) was similar to the pre-operative percentages of corresponding adipose tissue compartments (90.5%, 5.0%, 4.5%, respectively). Of note, participants with obstructive sleep apnea had significantly higher pre-operative volume of subcutaneous and intermuscular adipose tissue than participants without obstructive sleep apnea ( P = 0.003).

CONCLUSIONS

We found, contrary to what is reported to occur in adults, that pre-operative percentage loss of adipose tissue in subcutaneous, visceral, and intermuscular compartments was similar to the post-operative percentage loss of corresponding adipose tissue compartments in adolescents 12-26 weeks after sleeve gastrectomy.

Musculoskeletal effects of obesity and bariatric surgery – a narrative review

Obesity affects several areas of the human body, leading to increased morbidity and mortality and the likelihood of other diseases, such as type 2 diabetes mellitus, cardiovascular diseases and musculoskeletal disorders. These conditions predispose to bone fractures and sarcopenic obesity, defined by the presence of an obesity-associated decrease in muscle mass and strength. Both bone fragility and sarcopenic obesity disease are consequences of several factors, such as a low degree of chronic inflammation, insulin resistance, hormonal changes, nutritional deficiencies, ectopic fat deposits and sedentary lifestyle. The diagnosis of obesity-related musculoskeletal disorders is limited by the lack of sarcopenia criteria and lower accuracy of bone mineral density measurement by dual-energy X-ray absorptiometry in overweight people. Reducing body weight provides undeniable benefits to this population, however treating cases of severe obesity with bariatric surgery can cause even greater damage to bone and muscle health, especially in the long term. The mechanisms involved in this process are not yet fully understood, but factors related to nutrient malabsorption and mechanical discharge as well as changes in gut hormones, adipokines and bone marrow adiposity should be taken into account. Depending on the surgical technique performed, greater musculoskeletal damage may occur, especially in cases of malabsorptive surgeries such as Roux-en-Y gastric bypass, when compared to restrictive techniques such as sleeve gastrectomy. This difference is probably due to greater weight loss, nutrient malabsorption and important hormonal changes that occur as a consequence of the diversion of intestinal transit and loss of greater absorptive surface. Thus, people undergoing bariatric procedures, especially malabsorptive ones, should have their musculoskeletal health supervised to allow early diagnosis and appropriate therapeutic interventions to prevent osteoporotic fractures and preserve the functionality of the skeletal muscles.

Alcohol use, physical activity, and muscle strength moderate the relationship between body composition and frailty risk among people living with HIV

BACKGROUND

Antiretroviral therapy has improved life expectancy among people living with HIV (PLWH). Despite increased longevity, PLWH are at increased risk of age-related comorbidities, including frailty. We examined the relationship between body composition and frailty among PLWH, and moderation of this relationship by substance use, physical activity (PA), and physical function.

METHODS

Participants (n = 341; 71% male, 48 ± 10 years, body mass index (BMI) = 27.3 ± 7.0 kg/m2 ) enrolled in the New Orleans Alcohol Use in HIV (NOAH) study underwent measures of body composition, muscle strength, and gait speed. Whole blood phosphatidylethanol (PEth) was measured, and substance use and PA were self-reported. Frailty risk measures included the 58-Item Deficit Index (DI58) and the Veterans Aging Cohort Study (VACS) Index 1.0, where higher scores indicate greater frailty risk.

RESULTS

Multivariable linear regression adjusted for age, sex, and race showed that higher fat-free mass index (FFMI), body fat (%), waist-to-hip ratio, and body mass index (BMI) ≥ 25.0 kg/m2 vs. < 25.0 kg/m2 were significantly (p < 0.05) associated with decreased frailty risk measured by the VACS Index, whereas adjusted analyses showed no association between body composition variables and the DI58 score. Recent alcohol use, muscle strength, and PA, but not lifetime alcohol use or gait speed, significantly moderated associations between body composition variables and frailty risk with medium-to-large effect sizes. Subgroup analyses revealed a negative relationship between DI58 and FFMI among people with PEth > 8 ng/ml and negative relationships of VACS Index with FFMI and WHR in people with lower muscle strength. Overweight or obese BMI categories were positively associated with DI58 in people with lower muscle strength or higher PA level but negatively associated in those with higher muscle strength.

CONCLUSIONS

Our findings indicate that body composition has significant modulatory effects on frailty risk in PLWH, where obesity increases the risk of frailty and greater muscle mass may be protective, even in individuals who use alcohol. These results highlight the importance of considering body composition, physical activity, and physical function in assessing frailty risk in PLWH, particularly among individuals who use alcohol. Moreover, they support the implementation of physical activity interventions to ameliorate the risk of frailty in aging PLWH.

The Beneficial Effects of Bariatric-Surgery-Induced Weight Loss on Renal Function

Obesity represents an independent risk factor for the development of chronic kidney disease (CKD), leading to specific histopathological alterations, known as obesity-related glomerulopathy. Bariatric surgery is the most effective means of inducing and maintaining sustained weight loss. Furthermore, in the context of bariatric-surgery-induced weight loss, a reduction in the proinflammatory state and an improvement in the adipokine profile occur, which may also contribute to the improvement of renal function following bariatric surgery. However, the assessment of renal function in the context of obesity and following marked weight loss is difficult, since the formulas adopted to estimate glomerular function use biomarkers whose production is dependent on muscle mass (creatinine) or adipose tissue mass and inflammation (cystatin-c). Thus, following bariatric surgery, the extent to which reductions in plasma concentrations reflect the actual improvement in renal function is not clear. Despite this limitation, the available literature suggests that in patients with hyperfiltration at baseline, GFR is reduced following bariatric surgery, whereas GFR is increased in patients with decreased GFR at baseline. These findings are also confirmed in the few studies that have used measured rather than estimated GFR. Albuminuria is also decreased following bariatric surgery. Moreover, bariatric surgery seems superior in achieving the remission of albuminuria and early CKD than the best medical treatment. In this article, we discuss the pathophysiology of renal complications in obesity, review the mechanisms through which weight loss induces improvements in renal function, and provide an overview of the renal outcomes following bariatric surgery.

Metabolic Slowing Vanished 5 Years After Sleeve Gastrectomy in Patients With Obesity and Prediabetes/Diabetes

BACKGROUND

Resting energy expenditure (REE) decreases after weight loss more than expected according to body composition changes. Metabolic adaptation (MA) or metabolic slowing represents the difference between measured (m) and predicted (p) REE, and it is not clear whether it persists in the long-term. The aim of this study is to evaluate MA occurring 1 year (V1) and 5 years (V5) after laparoscopic sleeve gastrectomy (LSG) in patients with obesity and normal glucose tolerance, prediabetes (preDM) and type 2 diabetes (T2DM).

METHODS

We reassessed 37 patients (14 males/23 females) of 44.8 ± 10 years old, since they registered all the biochemical, body composition, and REE assessments at baseline (V0), V1, and V5. Physical activity (PA) was assessed by interview and questionnaire.

RESULTS

Patients displayed a percentage of weight loss of 31.5 ± 7.4% at V1 and a weight regain of 8.9 ± 7.5% at V5. Comparing V1 and V5, fat mass showed a slight increase (P = 0.011), while free fat mass remained unchanged (P = 0.304). PA improved at V1 (P < 0.001), remaining stable at V5 (P = 0.9). Measured REE (mREE) displayed a 31.2% reduction with a corresponding decrease of predicted REE (pREE) of 21.4% at V1, compared with V0 (P = 0.005), confirming a significant MA at V1. Conversely, no difference between mREE and pREE was observed at V5 (P = 0.112).

CONCLUSION

Our results suggested that only patients with preDM and T2DM displayed MA at V1, which vanished 5 years after LSG. Patients who practiced more PA prevent MA after surgery-induced wight loss.

Prevalence of low skeletal muscle mass following bariatric surgery

BACKGROUND AND AIMS

Evidence on the occurrence of low skeletal muscle mass (low-SMM) following bariatric surgery (BS) as well as on the impact of low-SMM antedating BS on post-surgical body composition (BC) are scant. In this context, we aimed to prospectively evaluate the prevalence of low-SMM prior to and up to 5 years after BS, and to evaluate pre-surgical low-SMM as an independent risk factor for the presence of low-SMM after BS.

METHODS

Retrospective analysis of prospectively collected database. BC was assessed by bioelectrical impedance analysis (BIA). A BIA-based formula was used to calculate skeletal muscle mass (SMM). Class I and class II low-SMM were defined respectively as a SMM index (SMMI = SMM/height²) value between -1 and -2, or > -2 standard deviations from the gender-specific regression line of the BMI versus the SMMI relationship in our reference group.

RESULTS

A total 952 subjects were included, with BC being available for 877 (92%) subjects at 12 months and for 576 subjects (60%) at 60 months after BS. Prior to surgery, and at 12-, or at 60-months after surgery, class I and class II low-SMM was ascertained respectively in 15.6% and 4.6%, 5.3% and 1.4%, and 16.6% and 6.3% of the study participants. Logistic regression analysis showed that the occurrence of low-SMM at 12- and 60-months follow-up, was independently predicted not only by age at the time of surgery [respectively, HR: 1.052 (95% CI 1.020-1.084), p = 0.001; and 1.042 (95% CI 1.019-1.066); p < 0.001] but also by the presence of low-SMM prior to surgery [respectively, HR: 10.717 (95% CI 5.771-19.904), p < 0.001; and 5.718 (95% CI 3.572-9.153); p < 0.001].

CONCLUSIONS

Our data suggest that a low-SMM phenotype occurs not only in obesity surgery candidates but also after BS, and that low-SMM prior to surgery is an important risk factor for low-SMM throughout post-surgical follow-up.

Validity of dual-energy x-ray absorptiometry for estimation of visceral adipose tissue and visceral adipose tissue change after surgery-induced weight loss in women with severe obesity

OBJECTIVE

Reliable and simple methods to quantify visceral adipose tissue (VAT) and VAT changes are needed. This study investigated the validity of dual-energy x-ray absorptiometry (DXA) compared with magnetic resonance imaging (MRI) for estimating VAT cross sectionally and longitudinally after surgery-induced weight loss in women with severe obesity.

METHODS

Women with obesity (n = 36; mean age 43 [SD 10] years; 89% White) with DXA and MRI before bariatric surgery (T0) at 12 (T12) and 24 months (T24) post surgery were included. CoreScan (GE Healthcare, Chicago, Illinois) estimated VAT from 20% of the distance between the top of the iliac crest and the base of the skull. MRI VAT (total VAT) was measured from the base of the heart to the sacrum/coccyx on a whole-body scan.

RESULTS

Mean DXA VAT was 45% of MRI VAT at T0, 46% at T12, and 68% at T24. DXA underestimated change in MRI VAT between T0 and T12 by 26.1% (0.81 kg, p = 0.03) and by 71.7% (0.43 kg, p < 0.001) between T12 and T24. The relationship between DXA VAT and MRI VAT differed between T12 and T24 (p value for interaction = 0.03).

CONCLUSIONS

CoreScan lacks validity for comparing VAT across individuals or for estimating the size of changes within individuals; however, within the limits of measurement error, it may provide a useful indicator of whether some VAT change has occurred within an individual.

Sarcopenia after Roux-en-Y Gastric Bypass: Detection by Skeletal Muscle Mass Index vs. Bioelectrical Impedance Analysis

Background: In sarcopenic patients the skeletal muscle reduction is the primary symptom of age- or disease-related malnutrition, which is linked to postoperative morbidity and mortality. The skeletal muscle mass index (SMI) from magnet resonance imaging (MRI) is increasingly used as a prognostic factor in oncologic and surgical patients, but under-represented in the field of obesity surgery. The bioelectrical impedance analysis (BIA), on the other hand is a commonly used method for the estimation of the body composition of bariatric patients, but still believed to be inaccurate, because of patient-related and environmental factors. The aim of this study was to compare the postoperative SMI values as a direct, imaging measured indicator for muscle mass with the BIA results in patients undergoing Roux-en-Y gastric bypass (RYGB). Methods: We performed a prospective single-center trial. Patients undergoing RYGB between January 2010 and December 2011 at our institution were eligible for this study. MRI and BIA measurements were obtained 1 day before surgery and at 6, 12 and 24 weeks after surgery. Results: A total of 17 patients (four male, 13 female, average age of 41.9 years) were included. SMI values decreased significantly during the postoperative course (p < 0.001). Comparing preoperative and postoperative measurements at 24 weeks after surgery, increasing correlations of SMI values with body weight (r = 0.240 vs. r = 0.628), phase angle (r = 0.225 vs. r = 0.720) and body cell mass (BCM, r = 0.388 vs. r = 0.764) were observed. Conclusions: SMI decreases significantly after RYGB and is correlated to distinct parameters of body composition. These findings show the applicability of the SMI as direct imaging parameter for the measurement of the muscle mass in patients after RYGB, but also underline the important role of the BIA, as a precise tool for the estimation of patients’ body composition at low costs. BIA allows a good overview of patients’ status post bariatric surgery, including an estimation of sarcopenia.

Obesity-Related Insulin Resistance: The Central Role of Adipose Tissue Dysfunction

Obesity is a key player in the onset and progression of insulin resistance (IR), a state by which insulin-sensitive cells fail to adequately respond to insulin action. IR is a reversible condition, but if untreated leads to type 2 diabetes alongside increasing cardiovascular risk. The link between obesity and IR has been widely investigated; however, some aspects are still not fully characterized.In this chapter, we introduce key aspects of the pathophysiology of IR and its intimate connection with obesity. Specifically, we focus on the role of adipose tissue dysfunction (quantity, quality, and distribution) as a driver of whole-body IR. Furthermore, we discuss the obesity-related lipidomic remodeling occurring in adipose tissue, liver, and skeletal muscle. Key mechanisms linking lipotoxicity to IR in different tissues and metabolic alterations (i.e., fatty liver and diabetes) and the effect of weight loss on IR are also reported while highlighting knowledge gaps.

Can exercise promote additional benefits on body composition in patients with obesity after bariatric surgery? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Bariatric surgery is the most effective treatment for patients with severe obesity, but success rates vary substantially. Exercise is recommended after bariatric surgery to reduce weight regain but the effectiveness remains undetermined on weight loss due to conflicting results. It is also unclear what should be the optimal exercise prescription for these patients. A systematic review and meta-analysis of randomized controlled trials on the effects of exercise on body weight (BW), anthropometric measures, and body composition after bariatric surgery was performed.

METHODS

PubMed/MEDLINE®, EBSCO®, Web of Science® and Scopus® databases were searched to identify studies evaluating exercise effectiveness.

RESULTS

The analysis comprised 10 studies (n = 487 participants). Exercise favored BW (-2.51kg; p = 0.02), waist circumference (-4.14cm; p = 0.04) and body mass index (-0.84kg·m-2; p = 0.02) reduction but no improvements in body composition. Combined exercise interventions were the most effective in reducing BW (-5.50kg; p < 0.01) and body mass index (-1.86kg·m-2; p < 0.01). Interventions starting >6-months after bariatric surgery were more successful in reducing BW (-5.02kg; p < 0.01) and body mass index (-1.62kg·m-2; p < 0.01).

CONCLUSION

Exercise, combined exercise regimens and interventions starting >6-months after bariatric surgery were effective in promoting BW, waist circumference and body mass index reduction. Exercise following bariatric surgery does not seem to favor body composition improvements.

Fat-Free Mass and Skeletal Muscle Mass Gain Are Associated with Diabetes Remission after Laparoscopic Sleeve Gastrectomy in Males but Not in Females

Besides massive body weight loss, laparoscopic sleeve gastrectomy (LSG) causes massive lean mass, including fat-free mass (FFM) and skeletal muscle mass (SM) that present higher metabolic rates in males. This study examines sex differences in FFM and SM changes of type 2 diabetes (T2D) remission at 12 months post-LSG. This cohort study recruited 119 patients (53.7% females) with T2D and obesity (body mass index 42.2 ± 7.0 kg/m²) who underwent LSG. Fat-mass (FM) loss was higher in males than in females (−12.8 ± 6.2% vs. −9.9 ± 5.0%, p = 0.02) after one-year post-operation. Regardless of the weight-loss difference, males had higher FFM and SM gain than did females (12.8 ± 8.0 vs. 9.9 ± 5.0% p = 0.02 and 6.5 ± 4.3% vs. 4.9 ± 6.2%, p = 0.03, respectively). Positive correlations of triglyceride reduction with FM loss (r = 0.47, p = 0.01) and SM gain (r = 0.44, p = 0.02) over 12 months post-operation were observed in males who achieved T2D remission. The T2D remission rate significantly increased 16% and 26% for each additional percentage of FFM and SM gain one year after LSG, which only happened in males. Increased FFM and SM were remarkably associated with T2D remission in males, but evidence lacks for females.

Long-term body composition improvement in post-menopausal women following bariatric surgery: a cross-sectional and case-control study

OBJECTIVE

Bariatric surgery (BS) induces loss of body fat mass (FM) with an inexorable loss of lean mass (LM). Menopause leads to deleterious changes in body composition (BC) related to estrogen deficiency including LM loss and increase in total and visceral adipose tissue (VAT). This study aims to describe the long-term weight evolution of post-menopausal women after Roux-en-Y gastric bypass (RYGB) and to compare the BC between BS patients vs post-menopausal non-operated women.

DESIGN

Cross-sectional study of 60 post-menopausal women who underwent RYGB ≥2 years prior to the study with nested case-control design.

METHODS

Post-menopausal BS women were matched for age and BMI with controls. Both groups underwent DXA scan, lipids and glucose metabolism markers assessment.

RESULTS

Median follow-up was 7.5 (2-18) years. Percentage of total weight loss (TWL%) was 28.5 ± 10%. After RYGB, LM percentage of body weight (LM%) was positively associated with TWL% and negatively associated with nadir weight. Forty-one post-BS women were age- and BMI-matched with controls. Post-BS patients showed higher LM% (57.7% (±8%) vs 52.5% (±5%), P = 0.001), reduced FM% (39.4% (±8.4%) vs 45.9% (±5.4%), P < 0.01) and lower VAT (750.6 g (±496) vs 1295.3 g (±688), P < 0.01) with no difference in absolute LM compared to controls. While post-BS women showed a better lipid profile compared to controls, no difference was found in glucose markers.

CONCLUSIONS

Post-menopausal women after RYGB have a lower FM and VAT, preserved LM and a better lipid profile compared to controls. Weight loss after RYGB seems to have a persistent positive impact on metabolic health.

The magnitude and progress of lean body mass, fat-free mass, and skeletal muscle mass loss following bariatric surgery: A systematic review and meta-analysis

Postbariatric loss of muscle tissue could negatively affect long-term health due to its role in various bodily processes, such as metabolism and functional capacity. This meta-analysis aimed to unravel time-dependent changes in the magnitude and progress of lean body mass (LBM), fat-free mass (FFM), and skeletal muscle mass (SMM) loss following bariatric surgery. A systematic literature search was conducted in Pubmed, Embase, and Web of Science. Fifty-nine studies assessed LBM (n = 37), FFM (n = 20), or SMM (n = 3) preoperatively and ≥1 time points postsurgery. Random-effects meta-analyses were performed to determine pooled loss per outcome parameter and follow-up time point. At 12-month postsurgery, pooled LBM loss was -8.13 kg [95%CI -9.01; -7.26]. FFM loss and SMM loss were -8.23 kg [95%CI -10.74; -5.73] and -3.18 kg [95%CI -5.64; -0.71], respectively. About 55% of 12-month LBM loss occurred within 3-month postsurgery, followed by a more gradual decrease up to 12 months. Similar patterns were seen for FFM and SMM. In conclusion, >8 kg of LBM and FFM loss was observed within 1-year postsurgery. LBM, FFM, and SMM were predominantly lost within 3-month postsurgery, highlighting that interventions to mitigate such losses should be implemented perioperatively.

Changes in Body Composition, Basal Metabolic Rate, and Blood Albumin during the First Year following Laparoscopic Mini-Gastric Bypass

Bariatric surgery is currently the only method that can significantly and continuously reduce weight and improve obesity-related comorbidities in morbidly obese patients. Significant weight loss through bariatric surgery can lead to changes in body composition. This study shows the changes in body composition, basal metabolic rate (BMR), and serum albumin in obese people following bariatric surgery. The study included 880 patients who underwent laparoscopic mini-gastric bypass surgery (LMGBP) between 2016 and 2020. The body mass index (BMI), bioelectrical impedance analysis (BIA), age, gender, blood albumin, WC (waist circumference), HC (hip circumference), BMR, and blood albumin were recorded at 0, 3, 6, and 12 months, postoperatively. The reduction in serum albumin concentration was not consistent with weight loss. Bariatric surgery promotes the breakdown of both fat and lean mass on the arms, torso, and thighs. This size reduction usually aggravates the concomitant skin redundancy in these areas which is a challenge for the plastic surgery team. Interestingly, the rate of lean mass reduction of the arms is faster than that of the torso and thighs. Excessive loss of lean body mass will also lower BMR and lead to subsequent weight gain. Despite the faster loss of proteins and lean mass in somatic areas, internal organs and viscera lose fats faster than proteins. According to this study, visceral proteins are the latest proteins to be affected by weight loss. This finding shows a different metabolic response of viscera comparing to somatic areas.

The Nonlinear Relationship Between Psoas Cross-sectional Area and BMI: A New Observation and Its Insights Into Diabetes Remission After Roux-en-Y Gastric Bypass

OBJECTIVE

To explore the potential relevance of muscle mass as a variable contributor to BMI in limitations on BMI-based predictions of diabetes remission (DR) after Roux-en-Y gastric bypass (RYGB).

RESEARCH DESIGN AND METHODS

We evaluated the relationship between muscle mass and BMI in 501 patients with type 2 diabetes mellitus and overweight or obesity, of whom 186 patients who underwent RYGB were studied for determination of the role of baseline muscle mass and BMI in predicting DR. Muscle mass was assessed by estimated fat-free mass index (eFFMI) and psoas cross-sectional area (CSA).

RESULTS

A nonlinear relationship existed between psoas CSA and BMI, whereas psoas CSA showed a highly positive correlation with eFFMI. Baseline psoas CSA and eFFMI were better than BMI for predicting 1- and 5-year DR.

CONCLUSIONS

The nonlinear relationship between muscle mass and BMI may partially contribute to BMI limitations in predicting DR after RYGB.

Evaluation of Stomatognathic System Parameters After Bariatric Surgery

PURPOSE

The present study aimed to evaluate electromyographic activity, bite strength, and masticatory muscle thickness in women without obesity and with severe obesity elected for bariatric surgery. Also, patients with obesity underwent bariatric surgery and were re-evaluated 3 and 6 months after surgery to analyze the influence of bariatric surgery outcomes on the stomatognathic system, a functional anatomical system comprising teeth, jaw, and associated soft tissues.

MATERIAL AND METHODS

Thirty-seven women were enrolled in the study. Twenty-one women with class II and III obesity according to the body mass index (BMI) and eligible for bariatric surgery composed the obesity pre-surgery group (Ob). Sixteen women with a normal weight according to BMI composed the non-obesity group (NOb). Afterward, the patients from the Ob group were followed up for 3 and 6 months after undergoing Roux-en-Y gastric bypass. Anthropometry, body composition, and parameters of the stomatognathic system were evaluated.

RESULTS

The stomatognathic system of the Ob group had less muscle activity and bite strength, but the thickness of masseter and temporal muscles was larger than the NOb group. We also observed a significant change in the muscular activity and bit strength of the stomatognathic system post-bariatric surgery.

CONCLUSION

Evaluating the stomatognathic system indicated that women with clinically severe obesity have less masticatory efficiency than non-obese. Also, we found a positive influence of bariatric surgery in masticatory activity after 3 and 6 months. Thus, monitoring the parameters of the stomatognathic system could be important in the indication and outcomes of bariatric surgery.

"Bioelectrical impedance analysis in managing sarcopenic obesity in NAFLD"

INTRODUCTION

Sarcopenic obesity and its association with nonalcoholic fatty liver disease (NAFLD) is under-recognized by many healthcare providers in Western medicine due to the lack of awareness and diagnostic guidelines. The result is delayed recognition and treatment, which leads to further health deterioration and increased healthcare costs. Sarcopenic obesity is characterized by the presence of increased fat mass in combination with muscle catabolism related to chronic inflammation and/or inactivity. Previous research has recommended evaluating body composition and physical function performance to adequately diagnose sarcopenic obesity. Body composition analysis can be performed by imaging applications through magnetic resonance imaging, computed tomography, and dual-energy x-ray absorptiometry. Due to the cost of each device and radiation exposure for patients as evidenced in all three modalities, bioelectrical impedance analysis offers a noninvasive approach capable of providing quick and reliable estimates of lean body and fat mass.

METHODS AND RESULTS

This review analyzes the current evidence-based literature, indicating a lower skeletal muscle mass and increased visceral adipose tissue correlation to the advancement of fibrosis in fatty liver disease.

CONCLUSION

Given the substantial promising research conducted in predominantly Asian populations regarding body tissue distribution and NAFLD, additional prospective research is needed to extend these findings in Western populations.

The Role of Elevated Branched-Chain Amino Acids in the Effects of Vertical Sleeve Gastrectomy to Reduce Weight and Improve Glucose Regulation

Elevated levels of branched-chain amino acids (BCAAs) and their metabolites are strongly positively associated with obesity, insulin resistance, and type 2 diabetes. Bariatric surgery is among the best treatments for weight loss and associated morbidities. Clinical studies have reported that bariatric surgery decreases the circulating levels of BCAAs. The objective of this study was to test the hypothesis that reduced BCAA levels contribute to the metabolic improvements of sustained weight loss and improved glucose tolerance after vertical sleeve gastrectomy (VSG). We find that, as in humans, circulating BCAAs are significantly lower in VSG rats and mice. To increase circulating BCAAs, we tested mice with either increased dietary intake of BCAAs or impaired BCAA catabolism by total body deletion of mitochondrial phosphatase 2C (Pp2cm). Our results show that a decrease in circulating BCAAs is not necessary for sustained body weight loss and improved glucose tolerance after VSG.

Increased branched-chain amino acid (BCAA) levels are biomarkers of metabolic disease, and bariatric surgeries reduce BCAA levels. Bozadjieva Kramer et al. show that both dietary and genetic manipulations can block the surgical effect on BCAAs but do not alter potent, beneficial effects on weight loss and glucose tolerance.

The Effect of Protein Consumption on Fat-Free Mass, Fat Mass, and Weight Loss 1 Year After Sleeve Gastrectomy and Roux-en-Y Gastric Bypass

OBJECTIVE

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) both limit protein and calorie intake and result in loss of fat-free mass (FFM), fat mass (FM), and weight. This study examined protein consumption and body composition changes after bariatric surgery.

METHODS

A prospective study of patients undergoing SG and RYGB between January 1 and December 31, 2016, with 1-year follow-up. Dietary, body composition, and physical activity data were collected at 3, 6, and 12 months post-operatively by bioelectric impedance and food records. Clinical laboratory data were obtained pre- and post-surgery.

RESULTS

One hundred and five patients (62 [59%] SG and 43 [41%] RYGB) were included in this study. Mean age was 31.8 ± 7.22 years. TWL% after 1 year in SG was 27.11% (p < 0.001) and that in RYGB was 30.41% (p < 0.0001). Reported protein consumptions after RYGB increased from 41.59 ± 22.86 g/day at 3 months (p = 0.004) to 57.90 ± 19.24 g/day at 12 months compared to 52.36 ± 25.04 g and 53.54 ± 29.75 g in SG. Similarly, energy intake after RYGB at 3 and 12 months increased from 895.9 ± 422.61 to 1188.15 ± 463.86 kcal/day compared to 1007.67 ± 422.62 to 1068 ± 575.89 kcal/day after SG (p = 0.009). There was a significant loss of fat-free mass and muscle mass in SG patients at 3 and 12 months from 61.58 ± 3.61 kg and 58.47 ± 3.09 kg to 54.18 ± 11.05 (p < 0.001) and 51.55 ± 10.62 (p = 0.004) but not in RYGB patients. Physical activity levels were similar in SG and RYGB patients.

CONCLUSION

There was a significant preservation of muscle mass after RYGB. Protein intake in majority of the patients was below 60 g/day during the first year after SG and RYGB.

Sarcopenia: What a Surgeon Should Know

Sarcopenia is an increasingly frequent syndrome characterized by generalized and progressive loss of muscle mass, reduction in muscle strength, and resultant functional impairment. This condition is associated with increased risk of falls and fractures, disability, and increased risk of death. When a sarcopenic patient undergoes major surgery, it has a higher risk of complications and postoperative mortality because of less resistance to surgical stress. It is not easy to recognize a sarcopenic patient preoperatively, but this is essential to evaluate the correct risk to benefit ratio. The role of sarcopenia in surgical patients has been studied for both oncological and non-oncological surgery. For correct surgical planning, data about sarcopenia are essential to design a correct tailored treatment.

Rate and Determinants of Excessive Fat-Free Mass Loss After Bariatric Surgery

Purpose

Fat-free mass (FFM) loss is a concerning aspect of bariatric surgery, but little is known about its time-course and factors related with excessive FFM loss. This study examined (i) the progress of FFM loss up to 3 years post-bariatric surgery and (ii) the prevalence and determinants of excessive FFM loss.

Materials and Methods

A total of 3596 patients (20% males, 43.5 ± 11.1 years old, BMI = 44.2 ± 5.5 kg/m²) underwent sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) surgery. Bioelectrical impedance analysis was performed preoperatively and 3, 6, 9, 12, 18, 24 and 36 months post-surgery. Changes in body composition were assessed by mixed model analysis. Prevalence of excessive FFM loss (based on three different cutoff values: ≥ 25%, ≥ 30% and ≥ 35% FFM loss/weight loss (= %FFML/WL)) was estimated and its determinants were assessed by linear regression analysis.

Results

Highest rates of FFM loss were found at 3 and 6 months post-surgery, reflecting 57% and 73% of peak FFM loss, respectively. Prevalence of excessive FFM loss ranged from 14 to 46% at 36 months post-surgery, with an older age (β = 0.14, 95%CI = 0.10–0.18, P < .001), being male (β = 3.99, 95%CI = 2.86–5.12, P < .001), higher BMI (β = 0.13, 95%CI = 0.05–0.20, P = .002) and SG (β = 2.56, 95%CI = 1.36–3.76, P < .001) as determinants for a greater %FFML/WL.

Conclusion

Patients lost most FFM within 3 to 6 months post-surgery. Prevalence of excessive FFM loss was high, emphasizing the need for more vigorous approaches to counteract FFM loss. Furthermore, future studies should assess habitual physical activity and dietary intake shortly after surgery in relation to FFM loss.

Electronic supplementary material

The online version of this article (10.1007/s11695-020-04654-6) contains supplementary material, which is available to authorized users.

Resting Energy Expenditure and Organ-Tissue Body Composition 5 Years After Bariatric Surgery

INTRODUCTION

Bariatric surgery-induced weight loss may reduce resting energy expenditure (REE) and fat-free mass (FFM) disproportionately thereby predisposing patients to weight regain and sarcopenia.

METHODS

We compared REE and body composition of African-American and Caucasian Roux-en-Y gastric bypass (RYGB) patients after surgery with a group of non-operated controls (CON). REE by indirect calorimetry; skeletal muscle (SM), trunk organs, and brain volumes by MRI; and FFM by DXA were measured at post-surgery visits and compared with CON (N = 84) using linear regression models that adjusted for relevant covariates. Ns in RYGB were 50, 42, and 30 for anthropometry and 39, 27, 17 for MRI body composition at years 1, 2, and 5 after surgery, respectively.

RESULTS

Regression models adjusted for age, weight, height, ethnicity, and sex showed REE differences (RYGB minus CON; mean ± s.e.): year 1 (43.2 ± 34 kcal/day, p = 0.20); year 2 (- 27.9 ± 37.3 kcal/day, p = 0.46); year 5 (114.6 ± 42.3 kcal/day, p = 0.008). Analysis of FFM components showed that RYGB had greater trunk organ mass (~ 0.4 kg) and less SM (~ 1.34 kg) than CON at each visit. REE models adjusted for FFM, SM, trunk organs, and brain mass showed no between-group differences in REE (- 15.9 ± 54.8 kcal/day, p = 0.8; - 46.9 ± 64.9 kcal/day, p = 0.47; 47.7 ± 83.0 kcal/day, p = 0.57, at years 1, 2, and 5, respectively).

CONCLUSIONS

Post bariatric surgery patients maintain a larger mass of high-metabolic rate trunk organs than non-operated controls of similar anthropometrics. Interpreting REE changes after weight loss requires an accurate understanding of fat-free mass composition at both the organ and tissue levels.

CLINICAL TRIAL REGISTRATION

Long-term Effects of Bariatric Surgery (LABS-2) NCT00465829.

Physical Activity Patterns Among Individuals Before and Soon After Bariatric Surgery

PURPOSE

Post-operative changes in moderate-to-vigorous physical activity (MVPA) may contribute to improved weight loss and long-term weight maintenance of individuals after bariatric surgery. Patients experience minimal changes in MVPA > 6 months after surgery, but no studies have investigated early changes in physical activity after surgery. This study aims to assess MVPA changes during the rapid weight loss phase through self-reporting and objective measures.

METHODS

Physical activity patterns were assessed as minutes per day spent doing MVPA. A walking cadence of ≥ 100 steps per minute defined MVPA. Individuals completing gastric bypass (N = 7) and sleeve gastrectomy (N = 17) procedures (21 females, 3 males, age 42.2 ± 12.6 years, body mass 121.8 ± 24.8 kg, BMI 44.0 ± 6.5) completed office visits at 12 ± 6 days pre- and 35 ± 10 days post-operative. Each wore an ActiGraph GT3X tri-axial accelerometer at the hip for 7 days before and again for 7 days 30.6 ± 10 days after surgery. Assessments also included a subjective question about their anticipated and perceived post-operative MVPA (scale of - 3 to 3 with 3 being much more physically active and - 3 being much less).

RESULTS

Participants did not change their minutes per day of MVPA significantly (pre-operative 1.5 ± 2.1; post-operative 2.6 ± 5.6, NS). Participants predicted their post-operative physical activity level would increase (2.8 ± 0.4). The self-reported activity level on the same scale after surgery was significantly less than predicted (1.9 ± 1.0, p < 0.05) but still suggested that participants thought they were more physically active.

CONCLUSION

Consistent with reports > 6 months after surgery, MVPA did not increase in the early post-operative period, despite patient expectations. The early post-operative period may be a time for behavioral intervention.

Improvement of glucose metabolism following rapid weight loss after bariatric surgery and its impact on reduction of visceral abdominal fat versus free fat muscle

BACKGROUND

Body fat distribution is highly associated with metabolic disturbances. Skeletal muscle plays an important role in glucose metabolism, as it serves as an important organ for glucose storage in the form of glycogen. In fact, low muscle mass has been associated with metabolic syndrome, type 2 diabetes (T2D), systemic inflammation, and decreased survival.

OBJECTIVES

To compare the relationship between visceral abdominal fat (VAF) and fat free mass (FFM) with the improved glucose metabolism after bariatric surgery.

SETTING

University hospital, United States.

METHODS

A retrospective review was performed of all patients who underwent bariatric surgery between 2011 and 2017 at a university hospital in the United States. In severely obese patients with T2D, we measured the VAF via abdominal computed tomography scan and we calculated the FFM preoperatively and at a 12-month follow-up. Data collected included baseline demographic characteristics and perioperative parameters, such as treatment for hypertension (HTN) and T2D, body mass index (BMI), glycated hemoglobin (HbA1C), glucose, and lipid profile.

RESULTS

A total of 25 patients met the inclusion criteria. The average age was 52.5 ± 11.6 years. The initial BMI was 41.41 ± 5.7 kg/m² and the postoperative BMI was 31.7 ± 6.9 kg/m² (P < .0001). The preoperative VAF volume was 184.6 ± 90.2 cm³ and the postoperative VAF volume was 93.8 ± 46.8 cm³ at the 12-month follow-up (P < .0001). The preoperative FFM was 55.2 ± 11.4 kg and the postoperative FFM was 49.1 ± 12 kg (P < .072). The preoperative HbA1C was 5.8% ± .9%, which decreased postoperatively to 5.3% ± .4% at the 12-month follow-up (P < .013).

CONCLUSION

Bariatric surgery has been demonstrated to be an effective treatment modality for severe obesity and T2D. Our results suggest that at 12 months, there is a reduction in VAF and HbA1C without a significant loss of FFM. Further prospective studies are needed to better understand these findings.

[Body composition assessment before and after weight loss following a Roux-en-Y gastric bypass. Are bioimpedanciometry estimations reliable?]

Introduction

Introduction: in patients with severe and morbid obesity it has been observed that bioimpedance (BIA) assessment generates an underestimation of fat mass (FM) and weight loss as FM after bariatric surgery, overestimating the loss of fat-free mass (FFM) and muscle mass. Objective: to evaluate the reliability of bioelectrical impedance analysis (BIA) to estimate total body water (TBW), fat-free mass (FFM), fat mass (FM), and its changes after 6 months of a Roux-en-Y gastric bypass (RYGBP), in patients with severe and morbid obesity. Methods: thirty-six patients approved for RYGBP were prospectively studied. TBW was measured by deuterium (D), and FM and FFM were calculated. A dual-frequency BIA device (5 and 200 kHz) (Bodystat Dualscan®) was used to estimate FM, FFM, TBW, extracellular water (ECW), intracellular water (ICW), and ECW/ICW ratio. Results: before RYGBP, BIA overestimated TBW by 2.6 ± 4.3 L (p = 0.002) and FFM by 3.5 ± 5.7 kg (p = 0.002), and underestimated FM% by 2.98 ± 4.7% (p = 0.002). The ECW/ICW ratio showed a significant and positive correlation with the difference BIA-D for FFM (r = 0.49; p = 0.002). After surgery, the differences between BIA and D were not significant, and the estimation error of FFM did not correlate with the ECW/ICW ratio. Conclusions: BIA generates an underestimation of FM as reported in patients with severe and morbid obesity, which is attenuated after weight reduction, underestimating weight loss as FM and overestimating FFM loss. Future research may assess whether these errors are reproduced by other BIA devices.

Assessment of body composition in obese patients undergoing one anastomosis gastric bypass: cross-sectional study

Bariatric surgery is the most effective long-term treatment to obesity, and it is necessary to assess changes in body composition and to be able to establish better follow-up of patients. Cross-sectional, observational study in patients undergoing One Anastomosis Gastric Bypass (OAGB) bariatric surgery. We analysed changes in weight and body composition during the first postoperative year. 405 patients (68.9% women. 31.1% men), mean age 44 years, mean weight 110.02 kg, Body Mass Index (BMI) 39.76 kg/m², height 1.66 m. The variables analyzed were substantially decreased compared to the preoperative values one year after surgery in every case: weight (110.02 ± 22.03 kg vs. 69.36 ± 13.60 kg), BMI (39.76 ± 6.65 vs. 24.52 ± 3. 76), fat free mass (61.12 ± 12.43 kg vs. 53.61 ± 11.61 kg), fat mass (50.44 ± 14.36 kg vs. 15.74 ± 6.74 kg), bone mass (58.06 ± 11.85 kg vs. 50.92 ± 11.06 kg) and water (45.08 ± 9.99 kg vs. 37.39 ± 9.23 kg), P < 0.001. The results show noticeable improvements in weight reduction and changes in body composition, and will contribute to develop a thorough understanding of both of them, contributing also to perform a better patients’ follow-up.

Performance of Glomerular Filtration Rate Estimating Equations Before and After Bariatric Surgery

Rationale & Objective

Evaluation of glomerular filtration rate (GFR) is challenging in adults undergoing bariatric surgery because creatinine and cystatin C levels are influenced by changes in muscle and fat mass. Additionally, indexing of GFR by body surface area (BSA) may by affected by decreases in BSA.

Study Design

Prospective observational study.

Setting & Participants

27 adults with body mass index (BMI) ≥ 35 kg/m² who underwent measurement of GFR before and after bariatric surgery.

Outcomes

Indexed and nonindexed GFRs measured (mGFRs) using plasma iohexol clearance, indexed and nonindexed estimated GFR (eGFR) based on levels of creatinine, cystatin C, or both from Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations.

Analytic Approach

Bias and percent of estimates within 20% and 30% of mGFR (P₂₀ and P₃₀) for estimating equations were examined.

Results

Mean presurgery BMI was 49.5 (SD, 9.4) kg/m², BSA was 2.42 (SD, 0.27) m², nonindexed mGFR was 117.3 (SD, 34.1) mL/min, and indexed mGFR was 84.1 (SD, 22.0) mL/min/1.73 m². After 6 months, mean BMI changed by –13.8 (95% CI, −15.9 to −11.8) kg/m², BSA by −0.30 (95% CI, −0.33 to −0.27) m², and nonindexed mGFR by −9.2 (95% CI, −17.2 to −1.1) mL/min, while indexed mGFR was unchanged at 5.1 (95% CI, −0.1 to 10.4) mL/min/1.73 m². Nonindexed eGFR_cr was unbiased (median bias, 5.0 [95% CI, −4.3 to 11.6] mL/min) before surgery, but overestimated mGFR (8.8 [95% CI, 1.8 to 16.9] mL/min) after surgery. Nonindexed eGFR_cys underestimated mGFR before (median bias, −12.1 [95% CI, −21.4 to −1.2] mL/min) and after surgery (−11.2 [95% CI, −21.8 to −7.3] mL/min). Nonindexed eGFR_cr-cys was unbiased before (median bias, −6.0 [95% CI, −11.0 to 1.0] mL/min) and after surgery (−2.0 [95% CI, −8.8 to 4.9] mL/min). Findings were similar for indexed eGFR compared with indexed mGFR.

Limitations

Small, mostly white sample.

Conclusions

Changes in indexed and nonindexed GFRs may be discordant after bariatric surgery in adults because of decreases in BSA. Indexed and nonindexed eGFR_cr-cys may be less biased than indexed or nonindexed eGFR_cr or eGFR_cys because of opposite biases in estimating mGFR.

Long-term effect of bariatric surgery on body composition in patients with morbid obesity: A systematic review and meta-analysis

We performed a meta-analysis to provide quantitative estimates of fat mass (FM) and fat-free mass (FFM) changes in patients following bariatric surgery over 1 year. A systematic search of PubMed, SCOPUS and Web of Science databases was conducted; the pooled weighted mean difference (WMD) and 95% confidence intervals (CI) were calculated using a random-effects model. Thirty-four studies including Roux en-Y gastric bypass (RYGB), sleeve gastrectomy (SG) biliopancreatic diversion (BPD) and gastric banding (GB) were analyzed. RYGB decreased in body FM (-28.99 kg [31.21, -26.77]) or FM% (-12.73% [-15.14, -10.32]) or FFM (-9.97 kg [-10.93, -9.03]), which were greater than SG and GB. Moreover, the FFM% in RYGB group (11.72% [7.33, 16.11]) was more than SG (5.7% [4.44, 6.95]) and GB (8.1% [6.15, 10.05]) groups. Bariatric surgeries, especially RYGB, might be effective for a decrease in FM and maintenance of FFM in patients with morbid obesity in over 1 year.

The Optimal Nutritional Programme for Bariatric and Metabolic Surgery

PURPOSE OF REVIEW

Bariatric surgery is the most effective treatment for severe and complex obesity; however, the risk of developing nutrient deficiencies varies based upon the type of surgery, degree of malabsorption, and level of nutrition intervention. There are numerous factors that can impact the nutrition status of a patient during their pre- and postoperative journey. We review the critical components and considerations needed in order to provide optimal nutrition care for patients with bariatric surgery.

RECENT FINDINGS

A dietitian, specializing in bariatric surgery, is the best equipped healthcare provider to prepare and support patients in achieving and maintaining optimal nutrition status. We present best practices for both the pre- and postoperative nutrition-related phases of a patient's journey. The dietitian specialist is integral in the assessment and ongoing nutrition care of patients with bariatric surgery. Further consideration should be given to enable access for lifelong follow-up and monitoring.

Anthropometrics by Three-Dimensional Photonic Scanner in Patients with Obesity Before and After Bariatric Surgery

BACKGROUND

We studied body composition by three-dimensional photonic scanning (3DPS) and metabolic biomarkers in a large ethnically diverse cohort of individuals with severe obesity before and after weight loss by Roux-en-Y gastric bypass (RYGB) or adjustable gastric banding (AGB) surgery.

MATERIALS AND METHODS

Male and female participants (n = 95) underwent 3DPS testing in the weeks preceding bariatric surgery (baseline), and 1 year after either RYGB (n = 34) or AGB (n = 9).

RESULTS

Principal component analysis showed that A1C and HDL cholesterol clustered with waist-to-hip ratio (WHR). Both RYGB and AGB surgeries led to similar improvements in A1C and lipids after 1 year. RYGB led to greater decreases in body weight, and in most anthropometric measures, compared with AGB at 1 year. However, after accounting for weight loss differences, RYGB and AGB groups did not differ in regional decreases in circumferences or volumes; the exception was a greater reduction in lean mass in RYGB compared with AGB.

CONCLUSION

Distribution of weight loss, assessed by 3DPS, did not differ between RYGB and AGB, but surgery type predicted change in lean mass at 1 year.

Bariatric Surgery: Remission of Inflammation, Cardiometabolic Benefits, and Common Adverse Effects

Obesity is associated with increased mortality as a result of several comorbidities which occur in tandem with the obese state. Chronic inflammation is well documented in obesity, and evidence from numerous studies support the notion that the increased inflammation in individuals with obesity accentuates the comorbidities seen in this condition. The remission of comorbidities such as metabolic, cardiovascular, and neurological complications occurs following bariatric procedures. Bariatric surgery significantly reduces mortality and results in remarkable weight loss and reversal in several obesity-related comorbidities. There is indisputable evidence that the resolution of inflammation that occurs after bariatric surgery mitigates some of these comorbidities. With the increasing use of bariatric surgery for the treatment of severe obesity, it is pivotal to elucidate the underlying mechanisms responsible for the notable improvements seen after the procedure. This review summarizes underlying mechanisms responsible for the remission of obesity-related abnormalities and discusses the common adverse effects of bariatric surgery. Well-stratified, large-scale studies are still needed for a proper evaluation of these underlying mechanisms.

Follow-up after bariatric surgery: A review

Bariatric surgery is becoming increasingly popular in the treatment of severely obese patients who failed to lose weight with the help of non-surgical interventions. Such patients are at increased risk for premature death, type 2 diabetes, high blood pressure, gallstones, coronary heart disease, dyslipidemia, some cancers, anxiety, depression, and degenerative joint disorders. Although bariatric surgery appears to be the most effective and durable treatment option for obesity, it is associated with a number of surgical and medical complications. These include a range of conditions, of which dumping syndrome and malnutrition due to malabsorption of vitamins and minerals are the most common. To achieve better surgery outcomes, a number of postsurgical strategies must be considered. The aim of this review was to describe possible complications, ailments, and important moments in the follow-up after bariatric surgery. Adequate lifelong monitoring is crucial for the achievement of long-lasting goals and reduction of post-bariatric complications.

The Effect of Metabolic Surgery on the Complications of Diabetes: What Are the Unanswered Questions?

It is now established that metabolic surgery (also known as bariatric surgery or obesity surgery) is an effective treatment for type 2 diabetes. Data from several randomized controlled trials have shown that surgery, when used as an adjunct to best medical therapy, is superior to medical therapy alone in achieving glycaemic and metabolic treatment targets in diabetes care. This has resulting in metabolic surgery being recommended as a treatment option for obesity-associated type 2 diabetes in national and international diabetes care guidelines. While the superior glycaemic effect of surgery is clear, the effect of surgery on the complications of diabetes is not fully understood. There are observational and epidemiological data that indicate a preventative effect in cohorts who do not have complications at baseline, as well as a positive effect on those with established diabetic kidney disease. However, there is a dearth of randomized controlled studies that specifically examine the effect of surgery on the complications of diabetes. Therefore, we should remain cautious in some cases, especially in those with retinopathy or neuropathy, as there is potential for deterioration of disease post-operatively. Further study is needed on this important topic. A lot is known, but there remain several unanswered questions. This article summarizes what we know about the effect of metabolic surgery on the complications of diabetes, poses some unanswered questions, and suggests how we could answer them.

Can Healthy Sleep Improve Long-Term Bariatric Surgery Outcomes? Results of a Pilot Study and Call for Further Research

Healthy sleep is associated with lower body weight and could improve and sustain weight loss following bariatric surgery. To support this premise, preliminary data on the relation between sleep duration and quality and long-term weight change in a subsample of participants from the Longitudinal Assessment of Bariatric Surgery are presented. Results indicate a relation between sleep duration and BMI and percent weight loss 9 years after surgery. Additionally, sleep quality explained 25% of the variance in weight change between 6- and 9-year follow-up visits. These data from a small exploratory study, in combination with the known effects of sleep on energy balance, suggest that sleep may play an important role in both immediate and sustained weight loss following bariatric surgery. Herein, a model of the proposed bidirectional relation between sleep and weight loss is presented as well as a call for systematic investigations of the influence of sleep on long-term weight management following bariatric surgery.

A Review of the Effects of Glucagon-Like Peptide-1 Receptor Agonists and Sodium-Glucose Cotransporter 2 Inhibitors on Lean Body Mass in Humans

Weight loss is an important goal in the management of several chronic conditions, including type 2 diabetes mellitus, and pharmacological therapies that aid weight loss are appealing. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2is) are novel glucose-lowering therapies that have been shown to induce clinically significant reductions in body weight. However, this weight loss may not be attributed solely to fat mass (FM). Given the importance of skeletal muscle and lean body mass (LBM) on cardio-metabolic health and physical function, we reviewed the available literature reporting the effects of GLP-1RAs and SGLT2is on body composition. Results demonstrate that, in most circumstances, the weight loss associated with both therapies predominantly comprises a reduction in FM, although significant heterogeneity exists between studies. In over half of the studies identified, the proportion of LBM reduction ranged between 20% and 50% of total weight lost, which is consistent with diet-induced weight loss and bariatric surgery. No clear differences existed between GLP-1RAs and SGLT2is. Consequently, the loss of LBM and skeletal muscle associated with weight loss induced by GLP-1RAs and SGLT2is warrants attention. Strategies to preserve skeletal muscle and improve physical function, for example through structured exercise, are of great importance.

Changes in Energy Expenditure of Patients with Obesity Following Bariatric Surgery: a Systematic Review of Prospective Studies and Meta-analysis

We herein summarize the available literature on the effects of bariatric surgery (BS) on energy expenditure in individuals with obesity. We conducted a systematic literature review, and 35 prospective studies met our inclusion criteria. The findings indicate that BS contributes to increased diet-induced thermogenesis (DIT) and decreased total energy expenditure (TEE) and resting energy expenditure (REE) in patients with obesity. The meta-analysis demonstrated a significant decrease in TEE and REE within 6 months following BS. With the sustained decrease in REE, there was no further decrease in TEE between the 6- and 12-month follow-up. Increased DIT might explain the variance between the patterns of REE and TEE change. The postoperative decrease in REE/FFM and increase in REE/BW were observed. The changes in substrate utilization might be consistent with the change in the respiration quotient postoperatively.

Comparative Effects of Medical Versus Surgical Weight Loss on Body Composition: a Pilot Randomized Trial

OBJECTIVE

Bariatric surgery leads to more rapid and greater weight loss (WL) compared to medical weight loss (MWL), but the differences in body composition (BC) changes for these modalities remain unclear. Due to the known health risks associated with central adiposity, we compared the changes in regional distribution of fat mass (FM) and lean mass (LM) after surgical versus MWL.

METHODS

In this 1:1:1 randomized trial among 15 persons with type 2 diabetes and body mass index (BMI) 30-39.9 kg/m², we compared changes in BC, by dual-energy X-ray absorptiometry and abdominal computerized tomography, at time of 10%WL or 9 months after intervention (whichever came first). Participants underwent MWL, adjustable gastric banding (AGB), or Roux-en-Y gastric bypass (RYGB). Non-parametric tests evaluated BC differences (FM, LM, and visceral adipose tissue [VAT]) within and across all three arms and between pair-wise comparisons.

RESULTS

Twelve female participants (75% African American) completed the study. Patient age, BMI, and baseline anthropometric characteristics were similar across study arms. AGB lost more LM (MWL - 5.2%, AGB - 10.3%, p = 0.021) and VAT (MWL + 10.9%, AGB - 28.0%, p = 0.049) than MWL. RYGB tended to lose more VAT (MWL +10.9%, RYGB - 20.2%, p = 0.077) than MWL. AGB tended to lose more LM than RYGB (AGB - 12.38%, RYGB - 7.29%, p = 0.15).

CONCLUSIONS

At similar WL, AGB lost more LM and VAT than MWL; RYGB similarly lost more VAT. Given the metabolic benefits of reducing VAT and retaining LM, larger studies should confirm the changes in BC after surgical versus medical WL.

CLINICAL TRIAL REGISTRATION

NCTDK089557 - ClinicalTrials.gov.