Associations of change in body fat percentage with baseline body composition and diabetes remission after bariatric surgery.

OBJECTIVE: The objective of this study was to determine the role of body fat percentage (BFP) changes in diabetes remission (DR) and the association between baseline body composition and its changes after bariatric surgery. METHODS: We analyzed 203 patients with type 2 diabetes who underwent Roux-en-Y gastric bypass. Body composition was measured using a gold-standard-derived predictive equation and magnetic resonance imaging. Body composition changes were calculated as 100 × (baseline value - follow-up value)/baseline value. We verified the results in a laparoscopic sleeve gastrectomy cohort with 311 patients. RESULTS: Compared with non-remission patients in the Roux-en-Y gastric bypass cohort, those who achieved DR showed a higher baseline fat-free mass index (FFMI) and experienced the most significant changes in BFP (p < 0.001). In comparative analyses, BFP changes were significantly better than BMI changes in identifying short- and long-term DR. Linear regression analysis identified FFMI as the most significant baseline variable correlated with BFP changes (p < 0.001). Baseline BMI was positively correlated with changes in BFP but negatively correlated with changes in FFMI. These findings were replicated in the laparoscopic sleeve gastrectomy cohort. CONCLUSIONS: BFP changes determine DR after bariatric surgery, and baseline FFMI is crucial for BFP changes. A low initial BMI is associated with a smaller BFP reduction and greater FFMI loss after bariatric surgery.

Nomogram for Predicting Remission of Metabolic Syndrome 1 Year after Sleeve Gastrectomy Surgery in Chinese Patients with Obesity.

PURPOSE: Sleeve gastrectomy (SG) is a widely used and effective treatment for patients with obesity and comorbid metabolic abnormalities. No specialized tool is available to predict metabolic syndrome (MS) remission after SG. We presented a nomogram that evaluated the probability of MS remission in obese patients 1 year after SG. MATERIALS AND METHODS: Patients with preoperative MS who underwent SG were enrolled in this retrospective study. They were divided into a training set and a validation set. Multivariate logistic regression analysis was performed to identify independent predictors of MS remission, and these predictors were included in the nomogram. Receiver operating characteristic curve was used to evaluate discrimination. Calibration was performed with the Hosmer-Lemeshow goodness-of-fit test. The net benefits of the nomogram were evaluated using decision curve analysis (DCA). RESULTS: Three hundred and eighteen patients with a median age of 34.0 years were analyzed. A training set and a validation set with 159 individuals each were established. A combination of age, preoperative high-density lipoprotein cholesterol, elevated triglycerides and glycated hemoglobin level independently and accurately predicted MS remission. The nomogram included these factors. The discriminative ability was moderate in training and validation sets (Area under curve 0.800 and 0.727, respectively). The Hosmer-Lemeshow X2 value of the nomogram was 8.477 (P = 0.388) for the training set and 5.361 (P = 0.718) for the validation set, indicating good calibration. DCA showed the nomogram had clinical benefits in both datasets. CONCLUSION: Our nomogram could accurately predict MS remission in Chinese patients with obesity 1 year after SG.

A Fusion Network with Stacked Denoise Autoencoder and Meta Learning for Lateral Walking Gait Phase Recognition and Multi-Step-Ahead Prediction.

Lateral walking gait phase recognition and prediction are the premise of hip exoskeleton application in lateral resistance walk exercise. In this work, we presented a fusion network with stacked denoise autoencoder and meta learning (SDA-NN-ML) to recognize gait phase and predict gait percentage from IMU signals. Experiments were conducted to detect the four lateral walking gait phases and predict their percentage in 10 healthy subjects across different speeds. The performance of SDA-NN-ML and other widely used algorithms including Support Vector Machine (SVM), Adaptive Boosting (AdaBoost) and Long Short Term Memory (LSTM) were evaluated. The cross-subject recognition accuracy of SDA-NN-ML (89.94%) decreased by 4.62% compared to the training accuracy, which outperformed SVM (8.60%), AdaBoost (5.61%), and LSTM (7.12%). For real-time and cross-subject prediction of gait phase percentage, the RMSE of SDA-NN-ML (0.2043) outperformed that of a single regression network (0.2426). With a signal noise ratio of 100:30, the cross-subject recognition accuracy decreased by a mere 5.70%, while the prediction result (RMSE) of SDA-NN-ML increased by 0.0167 when compared to the noise-free results. SDA-NN-ML demonstrates a stable multi-step-ahead prediction ability with an accuracy higher than 82.50% and an RMSE of less than 0.23 when the ahead time is less than 200 ms. The results demonstrated that the proposed method has high accuracy and robust performance in lateral walking gait recognition and prediction.

Associations of Serum Uric Acid to High-Density Lipoprotein Cholesterol Ratio with Trunk Fat Mass and Visceral Fat Accumulation.

Background: It has been reported recently that the ratio of uric acid to high-density lipoprotein cholesterol (UHR) is correlated with several metabolic disorders. The present study aimed to investigate the associations of UHR with body fat content and distribution. Methods: This study enrolled 300 participants (58 men and 242 women) aged 18 to 65 years. The levels of serum uric acid and high-density lipoprotein cholesterol were measured by standard enzymatic methods. The overall fat content and segmental fat distribution were assessed with an automatic bioelectrical impedance analyzer. In the population with obesity, the visceral fat area (VFA) and subcutaneous fat area (SFA) were measured using magnetic resonance imaging. Results: Among the study population, 219 individuals (73.0%) were with obesity. The median level of UHR in individuals with obesity was 33.7% (26.2% - 45.9%), which was significantly higher than that in those without obesity [22.6% (17.0% - 34.4%), P < 0.01]. UHR was positively associated with overall fat content and segmental fat distribution parameters (all P < 0.01). In multivariate linear regression analysis, compared with body mass index, waist circumference was more closely associated with UHR (standardized ß = 0.427, P < 0.001) after adjusting for confounding factors. Additionally, total fat mass (standardized ß = 0.225, P = 0.002) and trunk fat mass (standardized ß = 0.296, P = 0.036) were more closely linked to UHR than total fat-free mass and leg fat mass, respectively. In the population with obesity, VFA was independently correlated with UHR (P < 0.01), while SFA was not associated with UHR. Conclusion: UHR was significantly associated with overall fat content and trunk fat accumulation. In the population with obesity, UHR was positively associated with VFA. Attention should be paid to the role of excessive trunk fat mass in the relationship between UHR and metabolic disorders.

The impact of metabolic surgery on natural conception rates in women with infertility, obesity and polycystic ovary syndrome: a retrospective study.

BACKGROUND: Women with obesity and polycystic ovary syndrome (OPOS) are at high risk for infertility. However, the reproductive effects of metabolic surgery on women with infertility and OPOS have not been fully elucidated. OBJECTIVES: We investigated the natural conception rates after metabolic surgery, and the variables associated with infertility in women with OPOS. SETTING: Shanghai Sixth People's Hospital, Shanghai, China. METHODS: This study included 72 women with infertility and OPOS who underwent metabolic surgery and were followed up for 4 years after surgery. Finally, 54 patients completed the study. Reproductive outcomes were assessed, along with changes in anthropometric parameters and metabolic indices before and 1 year after surgery (prepregnancy). Logistic regression analysis was used to identify variables influencing natural conception and delivery outcomes. RESULTS: After metabolic surgery, 35 patients (64.8%) became pregnant naturally, while 16 were still unable to conceive naturally. Preoperative body mass index (BMI) tended to be lower in the natural conception group than in the no natural conception group (38.9 ± 6.9 versus 43.6 ± 11.0 kg/m2, P = .070) and there were no significant differences in weight loss between the 2 groups after surgery. Logistic regression analysis showed that the BMI 1 year after surgery (prepregnancy) was an independent predictor of natural conception, and receiver operating characteristic analysis showed that a BMI of 27.0 kg/m2 was the optimal cutoff for predicting successful natural conception after surgery. CONCLUSIONS: Metabolic surgery can improve fertility in women with OPOS. Patients with a BMI < 27.0 kg/m2 1 year after surgery (prepregnancy) are more likely to become pregnant naturally and give birth.

Investigating the Effect of Novel Gamified Stepper on Lower Limb Biomechanics in Seated Healthy Subjects.

The present study introduces a new gamified stepper device designed for bilateral lower limb rehabilitation, which is combined with a 3-D exergame. To the best of our knowledge, this is the initial study to utilize the stepping exercise for seated lower limb rehabilitation. The device comprises a stepping mechanism and a magnetic encoder. The modified stepper facilitates the bilateral training in the lower limb within its workspace. The magnetic encoder provides real-time rotational angle data during the exercise. A task-specific exergame platform was created and integrated with the device to enhance user compliance and engagement with the exercise. Experiments were conducted with ten healthy individuals with no history of lower limb injury to evaluate the system's feasibility for providing bilateral training and the effectiveness of the exergame platform. Participants were asked to perform bilateral lower limb exercise with a metronome and gamified stepper device in a seated position. Lower limb range of motion (ROM) and EMG activations were recorded during the exercises. The results indicate that the device was capable of providing cyclical ROM training with reduced muscle activation of the lower limb, and the exergame platform increased motivation to continue the exercises. This study can serve as the foundation for developing a robotic version of the proposed stepper device.

Effect of regional body composition changes on bone density remodeling after sleeve gastrectomy.

Background: Sleeve gastrectomy (SG) results in bone mineral density (BMD) loss and varying body composition parameters. However, the effects of body compositions on bone health are controversial. In order to accurately demonstrate their relationship and provide new insights into the causes of BMD loss after sleeve gastrectomy, this study is aimed to investigate the role of changes in body composition in BMD loss 12 months after SG. Methods: 41 Chinese individuals with obesity (25 women and 16 men) who underwent SG were prospectively examined for at least 12 months. Measurements of anthropometrics, body composition, BMD and blood samples were collected. Results: For 12 months, the femoral neck (FN) BMD and total hip (TH) BMD decreased significantly compared with baseline in both sexes but not lumbar spine (LS) BMD. Greater TH BMD loss was observed in men than in women. For the first 6 months post-SG, the FN BMD loss was positively associated with the estimated fat free mass index (eFFMI) reduction in women (adjusted ß = 0.77, P = 0.004) and positively associated with reduction of subcutaneous fat area (SFA) in men (r = 0.931, P = 0.007). For 12 months post-SG, the FN BMD loss was negatively associated with visceral fat area (VFA) reduction in women (adjusted ß = -0.58, P = 0.027) and men (adjusted ß = -0.68, P = 0.032). TH BMD loss was positively associated with waist circumference reduction in women (r = 0.448, P = 0.028). Conclusion: FN and TH BMD decrease after SG in both women and men. The changes in body compositions are associated with BMD loss at different time points and bone sites. Our data emphasize the limitation of simply taking the total weight loss (% TWL) as an influencing factor of bone mineral density and the necessity of delineating body composition in relevant studies.

A Novel Passive Back-Support Exoskeleton With a Spring-Cable-Differential for Lifting Assistance.

Lower back injuries are the most common work-related musculoskeletal disorders. As a wearable device, a back-support exoskeleton (BSE) can reduce the risk of lower back injuries and passive BSEs can achieve a low device weight. However, with current passive BSEs, there is a problem that the user must push against the device when lifting the leg to walk, which is perceived as particularly uncomfortable due to the resistance. To solve this problem, we propose a novel passive BSE that can automatically distinguish between lifting and walking. A unique spring-cable-differential acts as a torque generator to drive both hip joints, providing adequate assistive torque during lifting and low resistance during walking. The optimization of parameters can accommodate the asymmetry of human gait. In addition, the assistive torque on both sides of the user is always the same to ensure the balance of forces. By using a cable to transmit the spring force, we placed the torque generator on the person's back to reduce the weight on the legs. To test the effectiveness of the device, we performed a series of simulated lifting tasks and walking trials. When lifting a load of 10 kg in a squatting and stooping position, the device was able to reduce the activation of the erector spinae muscles by up to 41%. No significant change in the activation of the leg and back muscles was detected during walking.

Machine Learning Prediction of Iron Deficiency Anemia in Chinese Premenopausal Women 12 Months after Sleeve Gastrectomy.

Premenopausal women, who account for more than half of patients for bariatric surgery, are at higher risk of developing postoperative iron deficiency anemia (IDA) than postmenopausal women and men. We aimed at establishing a machine learning model to evaluate the risk of newly onset IDA in premenopausal women 12 months after sleeve gastrectomy (SG). Premenopausal women with complete clinical records and undergoing SG were enrolled in this retrospective study. Newly onset IDA after surgery, the main outcome, was defined according to the age- and gender-specific World Health Organization criteria. A linear support vector machine model was developed to predict the risk of IDA after SG with the top five important features identified during feature selection. Four hundred and seven subjects aged 31.0 (Interquartile range (IQR): 26.0-36.0) years with a median follow-up period of 12 (IQR 7-13) months were analyzed. They were divided into a training set and a validation set with 285 and 122 individuals, respectively. Preoperative ferritin, age, hemoglobin, creatinine, and fasting C-peptide were included. The model showed moderate discrimination in both sets (area under curve 0.858 and 0.799, respectively, p < 0.001). The calibration curve indicated acceptable consistency between observed and predicted results in both sets. Moreover, decision curve analysis showed substantial clinical benefits of the model in both sets. Our machine learning model could accurately predict newly onset IDA in Chinese premenopausal women with obesity 12 months after SG. External validation was required before the model was used in clinical practice.

Clusterin is closely associated with adipose tissue insulin resistance.

AIMS: Clusterin (encoded by CLU) is a novel adipokine. Serum clusterin levels were elevated in populations with obesity and diabetes. Adipose tissue insulin resistance (Adipo-IR) is proposed as an early metabolic defect that precedes systemic insulin resistance. Herein, we aimed to investigate the relationship between serum clusterin levels and Adipo-IR. CLU expression in human abdominal adipose tissues and clusterin secretion in human adipocytes was also explored. MATERIALS AND METHODS: A total of 201 participants (aged 18-62 years, 139 of whom were obese) were recruited. Enzyme-linked immunosorbent assay was used to measure serum clusterin levels. Adipo-IR was calculated from the product of fasting free fatty acids and fasting insulin levels. Transcriptome sequencing of abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) was performed. Human adipocytes were used to detect the secretion of clusterin. RESULTS: Serum clusterin levels were independently associated with Adipo-IR after adjusting for several confounding factors (standardised ß = 0.165, p = 0.021). CLU expression in VAT and SAT was associated with obesity-related metabolic risk factors. Higher CLU expression in VAT was accompanied by an increase in collagen accumulation. Clusterin secretion in differentiated human adipocytes was stimulated by insulin and inhibited by rosiglitazone. CONCLUSIONS: Clusterin is strongly associated with Adipo-IR. Serum clusterin may function as an effective indicator of adipose tissue insulin resistance.

Targeted gene panel provides advantages over whole-exome sequencing for diagnosing obesity and diabetes mellitus.

A small fraction of patients diagnosed with obesity or diabetes mellitus has an underlying monogenic cause. Here, we constructed a targeted gene panel consisting of 83 genes reported to be causative for monogenic obesity or diabetes. We performed this panel in 481 patients to detect causative variants and compared these results with whole-exome sequencing (WES) data available for 146 of these patients. The coverage of targeted gene panel sequencing was significantly higher than that of WES. The diagnostic yield in patients sequenced by the panel was 32.9% with subsequent WES leading to three additional diagnoses with two novel genes. In total, 178 variants in 83 genes were detected in 146 patients by targeted sequencing. Three of the 178 variants were missed by WES, although the WES-only approach had a similar diagnostic yield. For the 335 samples only receiving targeted sequencing, the diagnostic yield was 32.2%. In conclusion, taking into account the lower costs, shorter turnaround time, and higher quality of data, targeted sequencing is a more effective screening method for monogenic obesity and diabetes compared to WES. Therefore, this approach could be routinely established and used as a first-tier test in clinical practice for specific patients.

Percentage of maximum weight lost as an optimal parameter of weight regain after bariatric surgery in Chinese patients with diabetes.

OBJECTIVE: The goal of this study was to compare measures of weight regain (WR) and their association with the glucose metabolism deterioration within 3 years following bariatric surgery among Chinese patients with obesity and type 2 diabetes mellitus (T2DM). METHODS: Among a retrospective cohort of 249 patients with obesity and T2DM who underwent bariatric surgery and were followed up to 3 years, WR was assessed by weight changes, BMI changes, percentage of presurgery weight, percentage of nadir weight, and percentage of maximum weight lost (%MWL). Glucose metabolism deterioration was defined as a change from an absence of antidiabetic medication use to use, or absence of insulin use to use, or an increase in glycated hemoglobin by at least 0.5% to 5.7% or greater. RESULTS: A comparison of C-index of glucose metabolism deterioration indicated %MWL had better discriminatory ability versus weight change, BMI change, percentage of presurgery weight, or percentage of nadir weight (all p < 0.01). The %MWL also had the highest prediction accuracy. The optimal %MWL cutoff point was 20%. CONCLUSIONS: Among Chinese patients with obesity and T2DM who underwent bariatric surgery, WR quantified as %MWL predicted 3-year postoperative glucose metabolism deterioration better than the alternatives; 20% MWL was the optimal cutoff point.

A Cable-Driven Exoskeleton With Personalized Assistance Improves the Gait Metrics of People in Subacute Stroke.

Most stroke survivors have mobility deficits and show a pathological gait pattern. Seeking to enhance the gait performance among this population, we have developed a hybrid cable-driven lower limb exoskeleton (called SEAExo). This study aimed to determine the effects of SEAExo with personalized assistance on immediate changes in gait performance of people after stroke. Gait metrics (i.e., the foot contact angle, knee flexion peak, temporal gait symmetry indices) and muscle activities were the primary outcomes to evaluate the assistive performance. Seven subacute stroke survivors participated and completed the experiment with three comparison sessions, i.e., walking without SEAExo (served as baseline) and without/with personalized assistance, at their preferred walking speeds. Compared to the baseline, we observed increases in the foot contact angle and knee flexion peak by 70.1% ( ) and 60.0% ( ) with personalized assistance. Personalized assistance contributed to the improvements in temporal gait symmetry of more impaired participants ( ), and it led to a 22.8% and 51.3% ( ) reduction in the muscle activities of ankle flexor muscles. These results demonstrate that SEAExo with personalized assistance has the potential to enhance post-stroke gait rehabilitation in real-world clinical settings.

Inverse Optimal Adaptive Neural Control for State-Constrained Nonlinear Systems.

Optimizing a performance objective during control operation while also ensuring constraint satisfactions at all times is important in practical applications. Existing works on solving this problem usually require a complicated and time-consuming learning procedure by employing neural networks, and the results are only applicable for simple or time-invariant constraints. In this work, these restrictions are removed by a newly proposed adaptive neural inverse approach. In our approach, a new universal barrier function, which is able to handle various dynamic constraints in a unified manner, is proposed to transform the constrained system into an equivalent one with no constraint. Based on this transformation, a switched-type auxiliary controller and a modified criterion for inverse optimal stabilization are proposed to design an adaptive neural inverse optimal controller. It is proven that optimal performance is achieved with a computationally attractive learning mechanism, and all the constraints are never violated. Besides, improved transient performance is obtained in the sense that the bound of the tracking error could be explicitly designed by users. An illustrative example verifies the proposed methods.

Associations between serum clusterin levels and non-alcoholic fatty liver disease.

Objective: Clusterin is closely correlated with insulin resistance and its associated comorbidities. This study aimed to investigate the correlation between serum clusterin levels and non-alcoholic fatty liver disease (NAFLD) and further explore the mediating role of insulin resistance in this relationship. Methods: This study enrolled 195 inpatients (41 males and 154 females) aged 18-61 years. Twenty-four patients were followed up for 12 months after bariatric surgery. Serum clusterin levels were measured using a sandwich enzyme-linked immunosorbent assay. Fatty liver disease was diagnosed on the basis of liver ultrasonography. The fatty liver index (FLI) was calculated to quantify the degree of hepatic steatosis. The mediating role of homeostasis model assessment-insulin resistance (HOMA-IR) was assessed using mediation analysis. Results: Participants with NAFLD had significantly higher serum clusterin levels than those without NAFLD (444.61 (325.76-611.52) mg/L vs 294.10 (255.20-373.55) mg/L, P < 0.01). With increasing tertiles of serum clusterin levels, the prevalence of NAFLD displayed an upward trend (P < 0.01). Multivariate linear regression analysis showed that serum clusterin levels were a positive determinant of FLI (standardized ß = 0.271, P < 0.001) after adjusting for multiple metabolic risk factors. Serum clusterin levels significantly decreased after bariatric surgery (298.77 (262.56-358.10) mg/L vs 520.55 (354.94-750.21) mg/L, P < 0.01). In the mediation analysis, HOMA-IR played a mediating role in the correlation between serum clusterin levels and FLI; the estimated percentage of the total effect was 17.3%. Conclusion: Serum clusterin levels were associated with NAFLD. In addition, insulin resistance partially mediated the relationship between serum clusterin levels and FLI.

Decentralized Adaptive Neural Inverse Optimal Control of Nonlinear Interconnected Systems.

Existing methods on decentralized optimal control of continuous-time nonlinear interconnected systems require a complicated and time-consuming iteration on finding the solution of Hamilton-Jacobi-Bellman (HJB) equations. In order to overcome this limitation, in this article, a decentralized adaptive neural inverse approach is proposed, which ensures the optimized performance but avoids solving HJB equations. Specifically, a new criterion of inverse optimal practical stabilization is proposed, based on which a new direct adaptive neural strategy and a modified tuning functions method are proposed to design a decentralized inverse optimal controller. It is proven that all the closed-loop signals are bounded and the goal of inverse optimality with respect to the cost functional is achieved. Illustrative examples validate the performance of the methods presented.

Obesity-Induced Hepatic Steatosis Is Partly Mediated by Visceral Fat Accumulation in Subjects with Overweight/Obesity: A Cross-Sectional Study.

INTRODUCTION: We explored whether visceral fat accumulation mediates the development of hepatic steatosis in individuals living with overweight and obesity. METHODS: This cross-sectional study enrolled 769 outpatients with overweight and obesity aged 18-65 years. The controlled attenuation parameter (CAP) was used to quantify the degree of hepatic steatosis. Visceral fat accumulation, represented by the visceral fat area (VFA), was measured using magnetic resonance imaging. The associations of body mass index (BMI), VFA, and CAP with each other were assessed by univariate analysis, multivariate linear regression, and mediation analysis, respectively. RESULTS: Compared with women, male subjects had higher BMI, VFA, and CAP levels. In both sex, CAP was positively correlated with BMI and VFA by the univariate analysis. After adjusting for demographic and serum characteristics, the linear correlation coefficients between BMI and CAP were 1.738 (95% confidence interval (CI): 1.100, 2.377), 1.524 (95% CI: 0.798, 2.249), and 2.650 (95% CI: 1.292, 4.009) in all subjects, females, and males, respectively, while those between VFA and CAP were 0.190 (95% CI: 0.133, 0.247), 0.184 (95% CI: 0.117, 0.252), and 0.194 (95% CI: 0.086, 0.301). Mediation analysis showed that visceral fat accumulation contributed to 51.37%, 53.85%, and 26.51% of obesity-induced hepatic steatosis in the total, female, and male subjects, respectively. CONCLUSION: Visceral fat accumulation partially mediates obesity-induced hepatic steatosis in individuals with overweight and obesity, especially in women. More focus on visceral fat reduction is needed in individuals with obesity.