Revisiting the Ghrelin Changes Following Bariatric and Metabolic Surgery

Correlation analysis between the changes in plasma ghrelin level and weight loss after sleeve gastrectomy combined with fundoplication

BACKGROUND

Laparoscopic sleeve gastrectomy combined with fundoplication (LSGFD) can significantly control body weight and achieve effective anti-reflux effects. The aim of this study is to investigate the correlation between the alteration in Ghrelin levels and weight loss following SGFD, and to compare Ghrelin levels, weight loss and metabolic improvements between SG and SGFD, with the objective of contributing to the existing body of knowledge on SGFD technique in the management of patients with obesity and gastroesophageal reflux disease (GERD).

METHODS

A retrospective analysis was conducted on the clinical data of 115 obese patients who underwent bariatric surgery between March 2023 and June 2023 at the Department of Minimally Invasivew Surgery, Hernia and Abdominal Wall Surgery, People's Hospital of Xinjiang Uygur Autonomous Region. The subjects were divided into two groups based on surgical methods: sleeve gastrectomy group (SG group, 93 cases) and sleeve gastrectomy combined with fundoplication group (SGFD group, 22 cases). Clinical data, such as ghrelin levels before and after the operation, were compared between the two groups, and the correlation between changes in ghrelin levels and weight loss effectiveness after the operation was analyzed.

RESULTS

Three months after the operation, there was no significant difference in body mass, BMI, EWL%, fasting blood glucose, triglyceride, cholesterol, and uric acid levels between the SG and SGFD groups (P > 0.05). However, the SGFD group exhibited a significant decrease in body weight, BMI, and uric acid levels compared to preoperative levels (P < 0.05), while the decrease in ghrelin levels was not statistically significant (P > 0.05). Logistic regression analysis indicated that ghrelin levels three months after the operation were influential in postoperative weight loss.

CONCLUSION

The reduction of plasma Ghrelin level in patients after SGFD is not as obvious as that in patients after SG, but it can make obese patients get the same good weight loss and metabolic improvement as patients after SG. Ghrelin level at the third month after operation is the influencing factor of postoperative weight loss.

The circulating and central endocannabinoid system in obesity and weight loss

Major advances have been made in obesity treatment, focusing on restoring disturbances along the gut-brain axis. The endocannabinoid system (ECS) is a neuromodulatory signaling system, present along the entire gut-brain axis, that plays a critical role in central and peripheral regulation of food intake and body weight. Evidence on the impact of weight loss on the ECS is, however, more limited. Therefore, we set out to review the existing literature for changes in central and circulating endocannabinoid levels after bariatric surgery and other weight loss strategies in humans. The PubMed, Embase and Web of Science databases were searched for relevant articles. Fifty-six human studies were identified. Most studies measuring circulating 2-arachidonoylglycerol (2-AG) found no difference between normal weight and obesity, or no correlation with BMI. In contrast, studies measuring circulating arachidonoylethanolamine (AEA) found an increase or positive correlation with BMI. Two studies found a negative correlation between BMI and cannabinoid receptor type 1 (CB1) receptor availability in the brain. Only one study investigated the effect of pharmacological weight management on circulating endocannabinoid concentrations and found no effect on AEA concentrations. So far, six studies investigated potential changes in circulating endocannabinoids after bariatric surgery and reported conflicting results. Available evidence does not univocally support that circulating endocannabinoids are upregulated in individuals with obesity, which may be explained by variability across studies in several potential confounding factors (e.g. age and sex) as well as heterogeneity within the obesity population (e.g. BMI only vs. intra-abdominal adiposity). While several studies investigated the effect of lifestyle interventions on the circulating ECS, more studies are warranted that focus on pharmacologically and surgically induced weight loss. In addition, we identified several research needs which should be fulfilled to better understand the role of the ECS in obesity and its treatments.

Analysis of influencing factors and construction of prediction model for postoperative nausea and vomiting in patients undergoing laparoscopic sleeve gastrectomy: a single-center retrospective cohort study

BACKGROUND

With the increasing number of bariatric surgeries, the high incidence of postoperative nausea and vomiting (PONV) associated with this surgery has also gradually attracted attention. Among the common bariatric surgery methods, patients undergoing sleeve gastrectomy (SG) have the highest incidence of nausea and vomiting. The mechanism of occurrence of PONV is very complex. This study aims to explore the influencing factors of PONV in patients undergoing laparoscopic sleeve gastrectomy (LSG) and construct a nomogram prediction model based on these factors.

METHODS

With the approval of the Ethics Committee, the electronic medical records of patients who underwent LSG from July 2022 to May 2023 were collected retrospectively.

RESULTS

A total of 114 patients with complete medical records who underwent LSG from July 2022 to May 2023 were included in this study. Among them, 46 patients developed PONV, resulting in a PONV incidence rate of 40.4%. Multivariate logistic regression analysis revealed that female gender, the use of inhalation anesthesia, and operation time ≥ 120 min were risk factors for PONV in LSG. Additionally, the use of more than two kinds of antiemetic drugs was identified as a protective factor. Based on these factors, a nomogram model was constructed.

CONCLUSION

PONV in patients undergoing LSG is related to gender, type of anesthesia, duration of surgery, and combination therapy with antiemetic drugs. The nomogram prediction model constructed in this study demonstrates high accuracy and discrimination in predicting the occurrence of PONV in patients undergoing LSG.

Association of postoperative dietary macronutrient content and quality with total weight loss and fat-free mass loss at midterm after sleeve gastrectomy

OBJECTIVES

This study aimed to investigate the associations of macronutrient quantities and qualities with percentage total weight loss and percentage of fat-free mass loss relative to total weight loss in adults undergoing sleeve gastrectomy.

METHODS

This cross-sectional study included 146 patients on postoperative time since sleeve gastrectomy of 2 to 4 y. Diet was assessed using a food frequency questionnaire. Macronutrient quality index, carbohydrate quality index, fat quality index, and healthy plate protein quality index were calculated. The associations of dietary variables with percentage total weight loss and percentage of fat-free mass loss relative to total weight loss were determined using linear regression. Logistic regression was used to estimate the odds of non-response (percentage total weight loss < 25%) and excessive fat-free mass loss (percentage of fat-free mass loss relative to total weight loss > 28%) based on dietary intakes.

RESULTS

Forty-six (31.5%) were non-responders, and 49 (33.6%) experienced excessive fat-free mass loss. The fully adjusted model showed a 0.75 decrease in percentage total weight loss per 5% carbohydrate increase (95% CI, -1.45 to -0.05). The odds of non-response were 53% lower per 5% increase in protein (95% CI, 0.23-0.94). Each 5-g higher intake of fat was associated with 0.29 higher percentage of fat-free mass loss relative to total weight loss (95% CI, 0.03-0.55). The odds of excessive fat-free mass loss were reduced by 5% per gram of fiber intake (95% CI, 0.90-0.99). Each 5% increment in energy intake from protein that was isocalorically substituted for either carbohydrate or fat was associated with lower odds of nonresponse. Macronutrient quality indices had no significant associations.

CONCLUSIONS

Adherence to a high-protein, high-fiber diet after sleeve gastrectomy may enhance surgical success by improving total weight loss and preventing excessive fat-free mass loss.

Single anastomosis duodeno-ileal bypass with sleeve gastrectomy generates sustained improvement of glycemic control compared with sleeve gastrectomy in the diet-induced obese rat model

Bariatric surgery has become a recognized and effective procedure for treating obesity and type 2 diabetes (T2D). Our objective was to directly compare the caloric intake-independent effects of sleeve gastrectomy (SG) and single anastomosis duodenoileal bypass with SG (SADI-S) on glucose tolerance in rats with diet-induced obesity (DIO) and to elucidate the differences between bariatric surgery and caloric restriction.A total of 120 adult male Wistar rats with DIO and insulin resistance were randomly assigned to surgical (sham operation, SG, and SADI-S) and dietary (pair-feeding the amount of food eaten by animals undergoing the SG or SADI-S surgeries) interventions. Body weight and food intake were weekly monitored, and 6 weeks after interventions, fasting plasma glucose, oral glucose and insulin tolerance tests, plasma insulin, adiponectin, GIP, GLP-1, and ghrelin levels were determined.The body weight of SADI-S rats was significantly (p < 0.001) lower as compared to the sham-operated, SG, and pair-fed groups. Furthermore, SADI-S rats exhibited decreased whole body fat mass (p < 0.001), lower food efficiency rates (p < 0.001), and increased insulin sensitivity, as well as improved glucose and lipid metabolism compared to that of the SG and pair-fed rats.SADI-S was more effective than SG, or caloric restriction, in improving glycemic control and metabolic profile, with a higher remission of insulin resistance as well as long-term weight loss.

Precision nutrition in the context of bariatric surgery

Bariatric surgery (BS) is the most effective long-term treatment for severe obesity. This review summarizes the main nutritional deficiencies before and after BS, as well as current dietary and supplementation recommendations to avoid them. Likewise, we have reviewed all those aspects that in recent years have been shown to be related to postoperative weight loss (WL) and its subsequent maintenance, such as hormonal changes, dietary patterns, changes in food preference, adherence to recommendations and follow-up, genetic factors and microbiota, among others. Despite all the knowledge, nutritional deficiencies and weight regain after BS are frequent. It is essential to continue studying in this field in order to establish more precise recommendations according to the individual characteristics of patients. It is also a major objective to understand more deeply the role of the factors involved in WL and its maintenance. This will allow the development of precision treatments and nutrition for patients with obesity, optimizing their benefit after BS.

Towards an adiposity-related disease framework for the diagnosis and management of obesities

Obesity is a complex disease that relapses frequently and associates with multiple complications that comprise a worldwide health priority because of its rising prevalence and association with numerous complications, including metabolic disorders, mechanic pathologies, and cancer, among others. Noteworthy, excess adiposity is accompanied by chronic inflammation, oxidative stress, insulin resistance, and subsequent organ dysfunction. This dysfunctional adipose tissue is initially stored in the visceral depot, overflowing subsequently to produce lipotoxicity in ectopic depots like liver, heart, muscle, and pancreas, among others. People living with obesity need a diagnostic approach that considers an exhaustive pathophysiology and complications assessment. Thus, it is essential to warrant a holistic diagnosis and management that guarantees an adequate health status, and quality of life. The present review summarizes the different complications associated with obesity, at the same time, we aim to fostering a novel framework that enhances a patient-centered approach to obesity management in the precision medicine era.

Postoperative relative decrease in skeletal muscle mass as a predictor of quality of life in patients with gastric cancer

Low skeletal muscle mass reflects poor nutritional condition, which may impair the functional status and quality of life (QOL) of survivors of gastrectomy. The present cross-sectional study examined the association between a relative change in skeletal muscle mass and perceived postoperative health and QOL in patients with gastric cancer. The study comprised 74 patients (48 men and 26 women; median age, 68.5 years) who underwent surgery for stage I-III gastric cancer. Outcomes were measured using the Postgastrectomy Syndrome Assessment Scale-45, which was specifically developed to measure post-gastrectomy symptoms, living status, dissatisfaction with daily life and generic QOL. The skeletal muscle mass index (SMI) was estimated using computed tomography by tracing the area of the psoas major muscle to calculate the ΔSMI, defined as: (SMI before surgery-SMI at completion of the PGSAS-45 survey)/SMI before surgery x100. Associations between ΔSMI and health outcomes were assessed using univariate and multivariate analyses. The mean ΔSMI (SD) was 8.64% (10.6%). The effect size (Cohen's d) of ΔSMI <10% compared with ΔSMI ≥10% was 0.50 (95% CI: 0.02 to 0.97) for total symptom scores, -0.51 (-0.98 to -0.03) for general health, and -0.52 (-0.99 to -0.05) for the physical component summary (PCS). Multiple regression analysis showed that ΔSMI was significantly associated with PCS decline, and its standardized regression coefficient was -0.447 (-0.209 to -0.685). Determining ΔSMI may help clinicians to facilitate the objective evaluation of low skeletal mass, which reflects poor nutritional condition that can impair functional status and QOL of postoperative patients surviving gastrectomy.

The Relationship between Metabolic Comorbidities and Post-Surgical Weight Loss Outcomes in Adolescents Undergoing Laparoscopic Sleeve Gastrectomy

INTRODUCTION

Little is known about the relationship between metabolic factors and weight loss success in adolescents undergoing bariatric surgery.

METHODS

The objective of this study was to assess if baseline metabolic characteristics associate with weight loss in adolescents undergoing laparoscopic sleeve gastrectomy. A retrospective study was conducted in a comprehensive adolescent bariatric surgery center of 151 subjects (34 male, 117 female). Anthropometric measurements and metabolic factors including blood pressure, fasting glucose, hemoglobin A1c (HbA1c), metabolic syndrome (MeS), liver function, triglycerides, and waist circumference were collected at one pre-surgical visit and at 6- and/or 12-month post-laparoscopic sleeve gastrectomy. Weight loss was compared between subjects with normal or abnormal baseline metabolic factors. Absolute BMI change was used to measure successful weight loss.

RESULTS

Higher baseline systolic blood pressure (SBP) was associated with greater weight loss as measured by body mass index (BMI) change and BMI standard deviation score (BMI-SDS) change at 6 and 12 months. Those patients in the 6-month follow-up group with an abnormal HbA1c at baseline had significantly more weight loss as measured by BMI-SDS. None of the other parameters, including fasting glucose, MeS, liver function, triglycerides, and waist circumference showed a predictive relationship.

CONCLUSION

Elevated SBP and HbA1c in adolescents with morbid obesity may reflect a population more likely to achieve successful weight loss and, thus, may be a good target for bariatric surgery, specifically laparoscopic sleeve gastrectomy, as an intervention for severe obesity. An assessment of behavioral differences in patients with and without elevated BP and HbA1c might explain the mechanism for the improved weight loss.

Effect of Novel Gastro-Duodenal Flow Restrictor on Relative Weight Loss and Glucose Levels in a Porcine Model: A Pilot Randomized Study

Endoscopic bariatric and metabolic therapies are promising for obesity. We developed a novel gastro-duodenal flow restrictor (G-DFR) device for relative weight loss and lowering of glucose level and evaluated its safety and efficacy in a porcine model. The G-DFR comprised self-expandable gastro-duodenal partially covered polytetrafluoroethylene (PTFE) metal stent distally attached to a PTFE skirt. Eleven juvenile pigs were randomized into the evaluation of migration (n = 3), mid-term efficacy (n = 5), and control (n = 3) groups. Five pigs showed G-DFR migration at 2, 4, 7, and 10 weeks after placement in the migration and mid-term efficacy group. Compared to the control group, the mid-term efficacy group showed up to 55.4% relative weight loss in 12 weeks. Compared to the case group, the control group showed higher mean ghrelin hormone level from 6 to 12 weeks. Glucose level was significantly lower in the efficacy group than in the control group after 6 weeks. Serum alanine transferase levels and histological collagen deposition were lower in the liver of the case group than in the control group. Although it did not demonstrate consistent performance with respect to migration, a well-positioned G-DFR in the pyloroduodenal portion may lead to relative weight loss, lowering of glucose levels, and improved hepatic parameters.

Neurohormonal Changes in the Gut–Brain Axis and Underlying Neuroendocrine Mechanisms following Bariatric Surgery

Obesity is a complex, multifactorial disease that is a major public health issue worldwide. Currently approved anti-obesity medications and lifestyle interventions lack the efficacy and durability needed to combat obesity, especially in individuals with more severe forms or coexisting metabolic disorders, such as poorly controlled type 2 diabetes. Bariatric surgery is considered an effective therapeutic modality with sustained weight loss and metabolic benefits. Numerous genetic and environmental factors have been associated with the pathogenesis of obesity, while cumulative evidence has highlighted the gut–brain axis as a complex bidirectional communication axis that plays a crucial role in energy homeostasis. This has led to increased research on the roles of neuroendocrine signaling pathways and various gastrointestinal peptides as key mediators of the beneficial effects following weight-loss surgery. The accumulate evidence suggests that the development of gut-peptide-based agents can mimic the effects of bariatric surgery and thus is a highly promising treatment strategy that could be explored in future research. This article aims to elucidate the potential underlying neuroendocrine mechanisms of the gut–brain axis and comprehensively review the observed changes of gut hormones associated with bariatric surgery. Moreover, the emerging role of post-bariatric gut microbiota modulation is briefly discussed.

Thyroid Function Alteration in Obesity and the Effect of Bariatric Surgery

The most common endocrine disease in obesity is hypothyroidism and secondary endocrine alterations, including abnormal thyroid function, are frequent in obesity. It is unclear whether impaired thyroid function is the cause or the consequence of increased adiposity; furthermore, there are no clear data regarding the best way to dose levothyroxine for patients with both hypothyroidism and obesity, and the effect of bariatric surgery (BS). The aim of the present article is to review some controversial aspects of the relation between obesity and the thyroid: (1) Thyroid function in obesity and the effect of BS (2) Thyroid hormone treatment (THT) in obese patients with hypothyroidism and the effect of BS. In summary: In morbidly obese patients, TSH is moderately increased. Morbid obesity has a mild central resistance to the thyroid hormone, reversible with weight loss. In morbidly obese hypothyroid patients, following weight loss, the levothyroxine dose/kg of ideal weight did not change, albeit there was an increment in the levothyroxine dose/kg of actual weight. From a clinical practice perspective, in morbid obesity, diagnosing mild hypothyroidism is difficult, BS improves the altered thyroid function and THT can be adapted better if it is based on ideal weight.

New Insights on the Relationship between Leptin, Ghrelin, and Leptin/Ghrelin Ratio Enforced by Body Mass Index in Obesity and Diabetes

Currently, adipose tissue is considered an endocrine organ, however, there are still many questions regarding the roles of adipokines—leptin and ghrelin being two adipokines. The purpose of the study was to assess the relationship between the adipokines and their ratio with obesity and diabetes. Methods: Sixty patients (mean age 61.88 ± 10.08) were evaluated. Cardiovascular risk factors, leptin, ghrelin, and insulin resistance score values were assessed. The patients were classified according to their body mass index (BMI) as normal weight, overweight, and obese. Results: 20% normal weight, 51.7% overweight, 28.3% obese, and 23.3% diabetic. Obese patients had higher leptin values (in obese 34,360 pg/mL vs. overweight 18,000 pg/mL vs. normal weight 14,350 pg/mL, p = 0.0049) and leptin/ghrelin ratio (1055 ± 641 vs. 771.36 ± 921 vs. 370.7 ± 257, p = 0.0228). Stratifying the analyses according to the presence of obesity and patients’ gender, differences were found for leptin (p = 0.0020 in women, p = 0.0055 in men) and leptin/ghrelin ratio (p = 0.048 in women, p = 0.004 in men). Mean leptin/BMI and leptin/ghrelin/BMI ratios were significantly higher, and the ghrelin/BMI ratio was significantly lower in obese and diabetic patients. In conclusion, obesity and diabetes are associated with changes not only in the total amount but also in the level of adipokines/kg/m². Changes appear even in overweight subjects, offering a basis for early intervention in diabetic and obese patients.

Body Composition Changes Following Sleeve Gastrectomy Vs. One-Anastomosis Gastric Bypass: Tehran Obesity Treatment Study (TOTS)

PURPOSE

This study aimed to evaluate body composition changes and the determinants of fat-free mass loss (FFML) up to 3 years after sleeve gastrectomy (SG) and one-anastomosis gastric bypass (OAGB).

MATERIALS AND METHODS

A prospective study was conducted on 3864 patients with severe obesity who underwent either SG (2746, 76.1% women, mean age: 39.2 ± 11.6 years, and BMI: 44.3 ± 5.6 kg/m²) or OAGB (1118, 82.2% women, age: 39.9 ± 10.7 years, BMI: 45.6 ± 6.3 kg/m²). Body composition parameters were measured by bioelectrical impedance analysis preoperatively and 1, 3, 6, 9, 12, 18, 24, and 36 months after surgery. Changes in body composition were assessed using the propensity matched generalized estimated equation (GEE) method. The determinants of fat-free mass loss/weight loss (FFML/WL%) were defined using a mixed-model GEE analysis.

RESULTS

Means of FM, FFM, and FFML/WL% decreased significantly in both study groups (P_trend < 0.001). Changes in BMI, EWL%, FM, and FFML/WL% were different between the two groups (P_between < 0.05). The results showed a better FFM preservation and a greater FM loss over time in the OAGB group compared to the SG group (P_interaction < 0.05). FFML during the first 3 months was greater in the SG compared to the OAGB group (P < 0.001). SG surgery, higher preoperative BMI, and female gender were associated with greater FFML/WL%.

CONCLUSION

In the SG compared to the OAGB group, FFML was greater, especially early after the surgery, emphasizing the need for therapeutic interventions such as regular exercise programs and dietary intake modifications.

Evaluation of Thyroid Hormone Replacement Dosing in Morbidly Obese Hypothyroid Patients after Bariatric Surgery-Induced Weight Loss

The most frequent endocrine disease in obese patients is hypothyroidism. To date, there are no clear data regarding what happens to the dose of levothyroxine (LT4) after bariatric surgery (BS). The objective of the present study was to evaluate thyroid hormone replacement dose in morbidly obese hypothyroid patients after BS-induced weight loss. We explore the best type of measured or estimated body weight for LT4 dosing. We performed an observational study evaluating patients with morbid obesity and hypothyroidism who underwent BS. We included 48 patients (three men). In morbidly obese hypothyroid patients 12 months after BS-induced weight loss, the total LT4 dose or the LT4 dose/kg ideal body weight did not change, while there was a significant increase in LT4 dose/body surface area, LT4 dose/kg weight, LT4 dose/kg adjusted body weight, LT4 dose/kg body fat, and LT4 dose/kg lean body weight. There were no differences in LT4 dose and its variation between sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). The present study strongly suggests that LT4 dosing in obese hypothyroid patients can be individually adapted more precisely if it is based on ideal body weight.

Quantitative and Topographic Analysis by Immunohistochemical Expression of Ghrelin Gastric Cells in Patients with Morbid Obesity

PURPOSE

The cellular distribution of ghrelin positive cells is not well defined. The aim of the study is to quantify and determine the distribution of ghrelin cells in gastric mucosa in patients with morbid obesity and relate this finding to gender, comorbidities, gastritis, and plasmatic levels of acyl and desacylghrelin before and after laparoscopic sleeve gastrectomy.

PATIENT AND METHODS

We performed a study on 61 patients with BMI≥50 kg/m² operated by laparoscopic sleeve gastrectomy. Three gastric regions were analyzed by histopathology and immunohistology. Blood sample was taken before surgery, and at 6 and 12 months post-surgery, to study the plasma levels of ghrelin isoforms.

RESULTS

Ghrelin cells are present in all regions of the gastric mucosa, with a greater number in the body and the fundus. Difference was found in the antrum between male and female patients (p=0.018). Patients with arterial hypertension also showed a lower level of cells in antrum (p<0.05). Acylghrelin levels after surgery were significantly lower (32.83+5.6 pg/mL to 10.09+11.8 pg/mL, p<0.05). Values of desacylghrelin tended to decrease but no significant variation was observed (207.4+39.3 pg/mL to 188.84+52.3 pg/mL).

CONCLUSION

Our patients show ghrelin cells in all areas of the stomach. Gender, comorbidities, and gastritis are determinant on gastric ghrelin-producing cells distribution.