Cytokine, Chemokine, and Cytokine Receptor Changes Are Associated With Metabolic Improvements After Bariatric Surgery

Three-Month Excessive Body Weight Loss < 37.7% as a Predictor of Mid-term Suboptimal Outcomes Postlaparoscopic Sleeve Gastrectomy: Risk Factors and the Impact of Neutrophil-to-Lymphocyte Ratio on Adipocyte Function

INTRODUCTION

This study aimed to evaluate the impact of achieving < 37.7% excess body-weight loss (EBWL) within 3 months of postlaparoscopic sleeve gastrectomy (LSG) on clinical outcomes and its correlation with adipocyte function.

METHODS

Patients (n = 176) who underwent LSG between January 2019 and January 2023 were included. Weight loss and status of health markers were monitored postoperatively. The cohort was stratified based on EBWL < 37.7% at 3 months or not. Variables including neutrophil-to-lymphocyte ratio (NLR), insulin resistance, and comorbidities were analyzed. Omental visceral and subcutaneous adipose tissue samples were used to analyze the differences in adipocyte function by western blot.

RESULTS

Patients with EBWL < 37.7% at 3 months post-LSG (suboptimal group) comprised less likelihood of achieving ≥ 50% EBWL than those who achieved ≥ 37.7% EBWL (optimal group) at 6 months (42.55% vs. 95.52% in optimal group, p < 0.001), 12 months (85.11% vs. 99.25% in optimal group, p < 0.001) and 24 months (77.14% vs. 94.74% in optimal group, p = 0.009) post-LSG. High BMI (OR = 1.222, 95% CI 1.138-1.312, p < 0.001), NLR ≥ 2.36 (OR = 2.915, 95% CI 1.257-6.670, p = 0.013), and female sex (OR = 3.243, 95% CI 1.306-8.051, p = 0.011) significantly predicted EBWL < 37.7% at 3 months post-LSG. Patients with NLR ≥ 2.36 had significantly lower adipose triglyceride lipase in omental fat (p = 0.025).

CONCLUSION

EBWL < 37.7% at 3 months post-LSG is a strong predictor of subsequent suboptimal weight loss. High BMI, NLR ≥ 2.36, and female sex are risk factors in predicting EBWL < 37.7% at 3 months post-LSG. These findings may offer a reference to apply adjuvant weight loss medications to patients who are predisposed to suboptimal outcomes.

Adipose Tissue-Derived Mesenchymal Stromal Cells from Ex-Morbidly Obese Individuals Instruct Macrophages towards a M2-Like Profile In Vitro

Obesity, which continues to increase worldwide, was shown to irreversibly impair the differentiation potential and angiogenic properties of adipose tissue mesenchymal stromal cells (ADSCs). Because these cells are intended for regenerative medicine, especially for the treatment of inflammatory conditions, and the effects of obesity on the immunomodulatory properties of ADSCs are not yet clear, here we investigated how ADSCs isolated from former obese subjects (Ex-Ob) would influence macrophage differentiation and polarization, since these cells are the main instructors of inflammatory responses. Analysis of the subcutaneous adipose tissue (SAT) of overweight (OW) and Ex-Ob subjects showed the maintenance of approximately twice as many macrophages in Ex-Ob SAT, contained within the CD68＋/FXIII-A- inflammatory pool. Despite it, in vitro, coculture experiments revealed that Ex-Ob ADSCs instructed monocyte differentiation into a M2-like profile, and under inflammatory conditions induced by LPS treatment, inhibited HLA-DR upregulation by resting M0 macrophages, originated a similar percentage of TNF-α＋ cells, and inhibited IL-10 secretion, similar to OW-ADSCs and BMSCs, which were used for comparison, as these are the main alternative cell types available for therapeutic purposes. Our results showed that Ex-Ob ADSCs mirrored OW-ADSCs in macrophage education, favoring the M2 immunophenotype and a mixed (M1/M2) secretory response. These results have translational potential, since they provide evidence that ADSCs from both Ex-Ob and OW subjects can be used in regenerative medicine in eligible therapies. Further in vivo studies will be fundamental to validate these observations.

Impact of intestinal microenvironments in obesity and bariatric surgery on shaping macrophages

Obesity is associated with alterations in tissue composition, systemic cellular metabolism, and low-grade chronic inflammation. Macrophages are heterogenous innate immune cells ubiquitously localized throughout the body and are key components of tissue homeostasis, inflammation, wound healing, and various disease states. Macrophages are highly plastic and can switch their phenotypic polarization and change function in response to their local environments. Here, we discuss how obesity alters the intestinal microenvironment and potential key factors that can influence intestinal macrophages as well as macrophages in other organs, including adipose tissue and hematopoietic organs. As bariatric surgery can induce metabolic adaptation systemically, we discuss the potential mechanisms through which bariatric surgery reshapes macrophages in obesity.

Mechanisms of bariatric surgery for weight loss and diabetes remission

Obesity and type 2 diabetes(T2D) lead to defects in intestinal hormones secretion, abnormalities in the composition of bile acids (BAs), increased systemic and adipose tissue inflammation, defects of branched-chain amino acids (BCAAs) catabolism, and dysbiosis of gut microbiota. Bariatric surgery (BS) has been shown to be highly effective in the treatment of obesity and T2D, which allows us to view BS not simply as weight-loss surgery but as a means of alleviating obesity and its comorbidities, especially T2D. In recent years, accumulating studies have focused on the mechanisms of BS to find out which metabolic parameters are affected by BS through which pathways, such as which hormones and inflammatory processes are altered. The literatures are saturated with the role of intestinal hormones and the gut-brain axis formed by their interaction with neural networks in the remission of obesity and T2D following BS. In addition, BAs, gut microbiota and other factors are also involved in these benefits after BS. The interaction of these factors makes the mechanisms of metabolic improvement induced by BS more complicated. To date, we do not fully understand the exact mechanisms of the metabolic alterations induced by BS and its impact on the disease process of T2D itself. This review summarizes the changes of intestinal hormones, BAs, BCAAs, gut microbiota, signaling proteins, growth differentiation factor 15, exosomes, adipose tissue, brain function, and food preferences after BS, so as to fully understand the actual working mechanisms of BS and provide nonsurgical therapeutic strategies for obesity and T2D.

Oxidative and DNA damage in obese patients undergoing bariatric surgery: A one-year follow-up study

The pathogenesis of obesity and related comorbidities has long been associated with oxidative stress. The excess of adipose tissue contributes to the production of free radicals that sustain both a local and a systemic chronic inflammatory state, whereas its reduction can bring to an improvement in inflammation and oxidative stress. In our work, using the fluorescent lipid probe BODIPY® 581/591 C11 and the γH2AX foci assay, a well-known marker of DNA double strand breaks (DSB), we evaluated the extent of cell membrane oxidation and DNA damage in peripheral blood lymphocytes of normal weight (NW) controls and obese patients sampled before and after bariatric surgery. Compared to NW controls, we observed a marked increase in both the frequencies of oxidized cells or nuclei exhibiting phosphorylation of histone H2AX in preoperatory obese patients. After bariatric surgery, obese patients, resampled over one-year follow-up, improved oxidative damage and reduced the presence of DSB. In conclusion, the present study highlights the importance for obese patients undergoing bariatric surgery to also monitor these molecular markers during their postoperative follow-up.

High-throughput mediation analysis of human proteome and metabolome identifies mediators of post-bariatric surgical diabetes control

To improve the power of mediation in high-throughput studies, here we introduce High-throughput mediation analysis (Hitman), which accounts for direction of mediation and applies empirical Bayesian linear modeling. We apply Hitman in a retrospective, exploratory analysis of the SLIMM-T2D clinical trial in which participants with type 2 diabetes were randomized to Roux-en-Y gastric bypass (RYGB) or nonsurgical diabetes/weight management, and fasting plasma proteome and metabolome were assayed up to 3 years. RYGB caused greater improvement in HbA1c, which was mediated by growth hormone receptor (GHR). GHR’s mediation is more significant than clinical mediators, including BMI. GHR decreases at 3 months postoperatively alongside increased insulin-like growth factor binding proteins IGFBP1/BP2; plasma GH increased at 1 year. Experimental validation indicates (1) hepatic GHR expression decreases in post-bariatric rats; (2) GHR knockdown in primary hepatocytes decreases gluconeogenic gene expression and glucose production. Thus, RYGB may induce resistance to diabetogenic effects of GH signaling.

Trial Registration: Clinicaltrials.gov NCT01073020.

Factors underlying the effects of gastric bypass surgery on glucose homeostasis are incompletely understood. Here the authors developed and applied high-throughput mediation analysis to identify proteome/metabolome mediators of improved glucose homeostasis after to gastric bypass surgery, and report that improved glycemia was mediated by the growth hormone receptor.

Impact of Bariatric Surgery on Adipose Tissue Biology

Bariatric surgery (BS) procedures are actually the most effective intervention to help subjects with severe obesity achieve significant and sustained weight loss. White adipose tissue (WAT) is increasingly recognized as the largest endocrine organ. Unhealthy WAT expansion through adipocyte hypertrophy has pleiotropic effects on adipocyte function and promotes obesity-associated metabolic complications. WAT dysfunction in obesity encompasses an altered adipokine secretome, unresolved inflammation, dysregulated autophagy, inappropriate extracellular matrix remodeling and insufficient angiogenic potential. In the last 10 years, accumulating evidence suggests that BS can improve the WAT function beyond reducing the fat depot sizes. The causal relationships between improved WAT function and the health benefits of BS merits further investigation. This review summarizes the current knowledge on the short-, medium- and long-term outcomes of BS on the WAT composition and function.

Factors Affecting Metabolic Outcomes Post Bariatric Surgery: Role of Adipose Tissue

Obesity is an ever-growing public health crisis, and bariatric surgery (BS) has become a valuable tool in ameliorating obesity, along with comorbid conditions such as diabetes, dyslipidemia and hypertension. BS techniques have come a long way, leading to impressive improvements in the health of the majority of patients. Unfortunately, not every patient responds optimally to BS and there is no method that is sufficient to pre-operatively predict who will receive maximum benefit from this surgical intervention. This review focuses on the adipose tissue characteristics and related parameters that may affect outcomes, as well as the potential influences of insulin resistance, BMI, age, psychologic and genetic factors. Understanding the role of these factors may help predict who will benefit the most from BS.

A combination of circulating chemokines as biomarkers of obesity-induced insulin resistance at puberty

BACKGROUND

In obesity adipose tissue undergoes structural re-modelling leading to a chronic low-grade inflammatory state linked to insulin resistance (IR).

OBJECTIVE

We aimed to develop a clinically relevant biomarker model for stratifying IR in adolescents with obesity.

METHODS

Cytokines [tumour cell derived factor 1α, monocyte chemoattract protein (MCP) 1, eotaxin and fractalkine], growth factors [brain-derived neurotrophic factor, pro-fibrotic platelet-derived growth factor (PDGF-BB) and insulin-like growth factor 1] and biochemical/metabolic factors were analysed in serum of 143 pubertal patients with obesity (50% IR; 50% non-IR) and 33 controls. Factor analysis, correlation, binary logistic regression and receiver operating characteristic analysis were used to evaluate combinations of these biomarkers as possible diagnostic tools for IR.

RESULTS

Two biomarker IR models combining levels of triglycerides (TG)/HDL, eotaxin, MCP-1 and PDGF-BB in pubertal patients with obesity of both sexes were defined. Altered levels of MCP-1, eotaxin, and PDGF-BB constitute a main component that determines 27.7% of the variance explaining IR. Growth and inflammatory factors comprise two other components linked to the first, together accounting for 59.2% of the variance determining IR.

CONCLUSIONS

PDGF-BB, MCP-1, eotaxin, TG and cholesterol concentrations constitute a solid panel of biomarkers associated with IR in pubertal children with obesity that could be useful in their stratification in a clinical setting for stratification.

The Collision of Meta-Inflammation and SARS-CoV-2 Pandemic Infection

The coronavirus disease 2019 (COVID-19) pandemic has forced us to consider the physiologic role of obesity in the response to infectious disease. There are significant disparities in morbidity and mortality by sex, weight, and diabetes status. Numerous endocrine changes might drive these varied responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including hormone and immune mediators, hyperglycemia, leukocyte responses, cytokine secretion, and tissue dysfunction. Studies of patients with severe COVID-19 disease have revealed the importance of innate immune responses in driving immunopathology and tissue injury. In this review we will describe the impact of the metabolically induced inflammation (meta-inflammation) that characterizes obesity on innate immunity. We consider that obesity-driven dysregulation of innate immune responses may drive organ injury in the development of severe COVID-19 and impair viral clearance.

Leptin mediates improvements in cognitive function following treatment with infliximab in adults with bipolar depression

A potential role for leptin in the pathophysiology of bipolar disorder (BD) has been proposed. We recently investigated the effects of the tumor necrosis factor-alpha (TNF-α) antagonist infliximab in individuals with bipolar depression. Leptin is known to interact with the TNF-α system. Herein, we aimed to explore infliximab's effects on leptin and its relationship with brain structure and function. Sixty adults with bipolar depression were enrolled in this randomized, double-blind, 12-week clinical trial of adjunctive infliximab (n = 29) and saline control (n = 31), which were administered intravenously at weeks 0, 2, and 6. Plasma concentrations of leptin, TNF-α and soluble TNF receptors (sTNFR) 1 and 2 were assessed at weeks 0, 2, 6, and 12. We observed a significant decrease in leptin levels in infliximab-treated patients, relative to placebo. Infliximab treatment also significantly reduced TNF-α and sTNFR2, but not sTNFR1 levels. Changes in sTNR2 levels at week 6 significantly determined changes in leptin at week 12 in infliximab-, but not placebo-treated participants. Improvements in verbal memory and increases in global cortical volume were associated with reduction in leptin levels in the treatment group. Mediation analysis indicated that cognitive improvement in infliximab-treated patients was mediated by reductions in leptin levels, which in its turn were determined by decreases in sTNR2 levels. In conclusion, infliximab treatment reduced plasma leptin levels in individuals with BD, through modulation of sTNFR2. Decreases in leptin signaling were associated with an increase in global cortical volume and better performance in a verbal memory task.

The Correlation Between RDW, MPV and Weight Indices After Metabolic Surgery in Patients with Obesity and DM/IGR: Follow-Up Observation at 12 Months

INTRODUCTION

Red blood cell distribution width (RDW) and mean platelet volume (MPV) are both new biomarkers for the prognosis of many diseases. This study aimed to observe the predictive values of RDW and MPV for weight loss after different metabolic surgeries in patients with obesity and abnormal glucose metabolism [diabetes mellitus or impaired glucose regulation (DM/IGR)].

METHODS

We retrospectively analyzed the body weight (BW), body mass index (BMI) and blood routine index of 98 patients with obesity and DM/IGR who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG).

RESULTS

Levels of RDW and MPV in both groups were significantly higher than before 1 month after surgery and then gradually decreased. Twelve months after surgery, the RDW level in the RYGB group was significantly lower than that before surgery. In the RYGB group, the RDW level of patients in the high-level percentage weight loss (%BW) (≥ 31.90) at 6 and 12 months after surgery decreased significantly compared to those in the corresponding low level. %BW and change in BW and BMI (ΔBW and ΔBMI) at 6 and 12 months after surgery in the high-level RDW (≥ 12.90) before surgery were significantly higher than those in the low level in the RYGB group. No significant difference in weight index was found in the high and low levels of the MPV before surgery in either group at other follow-up time points.

CONCLUSIONS

Preoperative baseline RDW and postoperative RDW levels can preliminarily predict the effect of different metabolic surgeries in patients with obesity and DM/IGR.

Effect of weight loss induced by laparoscopic sleeve gastrectomy on liver histology and serum adipokine levels

BACKGROUND & AIM

Bariatric surgery is a valid treatment option for persons with non-alcoholic fatty liver disease. This study prospectively examined the impact of laparoscopic sleeve gastrectomy (LSG) on liver histopathology, and blood levels of adiponectin, leptin, resistin, and pre-B cell enhancing factor/Nampt/visfatin.

PATIENTS & METHODS

In 81 patients with non-alcoholic fatty liver disease who underwent LSG, paired liver biopsies and blood specimens were obtained before and 18 months after LSG. Differences between preoperative and 18 months postoperative data were tested by paired Student's t-test or Wilcoxon rank test as appropriate.

RESULTS

At follow up, there was a significant improvement in biochemical markers for glucose homeostasis, including fasting glucose, HbA1c, insulin levels, and homeostatic model assessment index. Postoperative liver function tests, namely serum alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase level, showed a significant improvement compared to before weight loss. The number of patients who had definite, borderline, or no non-alcoholic steatohepatitis was 43 (53%), 27 (33%), and 11 (14%), respectively, at baseline, and 9 (11%), 32 (40%), and 40 (49%) at 18-month post-surgery follow up. A significant reduction in steatosis, liver fibrosis, lobular inflammation, and hepatocyte ballooning was observed in the postoperative biopsies (P < 0.001 each). In addition, at the follow-up assessment, there was a significant increase in serum adiponectin levels and significant decline in serum levels of leptin, resisitin, and pre-B cell enhancing factor/Nampt/visfatin.

CONCLUSION

Weight loss after sleeve gastrectomy was associated with a significant improvement in several metabolic parameters, liver enzyme levels, liver histopathology, and changes in serum adipokine levels towards antidiabetic and anti-inflammatory profiles.

Obesity-associated T-cell and macrophage activation improve partly after a lifestyle intervention

BACKGROUND

The relation between low-grade inflammation and metabolic dysfunction in obesity is not fully explored.

OBJECTIVE

To evaluate immune parameters in the obese state and after a lifestyle intervention program.

METHODS

Patients with obesity (n = 87) from an academic obesity clinic were compared with controls with regard to macrophage and T-cell activation (reflected by serum levels of soluble CD163 (sCD163) and soluble IL-2 receptor (sIL-2R), respectively), and an array of cytokines, chemokines, and growth factors. In addition, these parameters and regulatory T-cells (Treg), were studied in 27 patients who followed a 75-week lifestyle intervention (dietary advice, exercise, and psychoeducation).

RESULTS

Mean sIL-2R and sCD163 levels were higher in patients than controls (sIL-2R:2884 ± 936 pg/ml vs. 2207 ± 813 pg/ml, p = 0.001; sCD163:1279 ± 580 pg/ml vs. 661 ± 271 pg/ml, p < 0.0001 respectively). Patients with metabolic syndrome (MetS) had higher sCD163 than those without (1467 ± 656 pg/ml vs. 1103 ± 438 pg/ml). Patients had higher IL-1β, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-15, IL-17A, MCP-1/CCL2, MIP-1α/CCL3, MIP-1β/CCL4, G-CSF, GM-CSF, FGF, IFN-γ, and TNF-α than controls, whereas VEGF-A, PDGF-BB, and eotaxin were lower. Upon intervention, sIL-2R decreased while peripheral Treg frequencies increased within the reference range (p = 0.042 and p = 0.005 respectively). The sIL-2R decrease correlated to a decrease in waist circumference (rho = 0.388, p = 0.045) and in trend to a decrease in MetS components (rho = 0.345, p = 0.078). The Treg increase was unrelated to weight loss or metabolic improvement. Mean sCD163 did not change significantly upon intervention, nor did the cytokines, chemokines, and growth factors (except IP-10/CXCL10).

CONCLUSION

In obesity, T-cell homeostasis improves after a lifestyle intervention. Immunologic alterations can occur independently of metabolic improvement.

Use of the microbiome in the management of children with type 2 diabetes mellitus

PURPOSE OF REVIEW

The purpose of this review is to present recent data that defines our current understanding of the role of the gut microbiome in the development of T2DM.

RECENT FINDINGS

Recent studies focus on the physiology and molecular pathways of the gut microbiome-host interaction. Short-chain fatty acids (SCFAs) derived from the fermentation of plant-based nonsoluble fiber bind to G-protein-coupled receptors (GPR) GPR 41 and GPR 43 to induce enteroendocrine molecules that control appetite, and to upregulate intestinal gluconeogenesis gene expression that controls glucose regulation. "Metabolic endotexemia" reflects a state of low-grade systemic inflammation that results from lipopolysaccharide (LPS) release from the gut into the systemic circulation in response to a high-fat diet. Inflammatory pathways induced by LPS, activation of toll-like receptor-4 (TLR-4), and other inflammatory signaling pathways are mediators of systemic inflammation, insulin resistance and type II diabetes mellitus.

SUMMARY

Recent scientific data support that derangements in the composition of the microbiota, termed "microbiome dysbiosis" is a factor in the development of "metabolic endotoxemia" and T2DM. Therapeutic options that target the gut microbiome in the treatment of T2DM are explored.

Endocrine implications of bariatric surgery: a review on the intersection between incretins, bone, and sex hormones

Bariatric surgery is now the most widely used intervention for the treatment of human obesity. A large body of literature has demonstrated its efficacy in sustained weight loss and improvement in its associated comorbidities. Here, we review the effect of bariatric surgery in gut hormone physiology, bone remodeling and the reproductive axis. Rapid improvements in insulin release and sensitivity appear to be weight loss independent and occur immediately after surgery. These effects on pancreatic beta cells are mostly due to increased gut hormone secretion due to augmented nutrient delivery to the small intestine. Bone remodeling is also affected by gut hormones. Phenotypic skeletal changes observed in mice deficient in GLP-1 or GIP suggest that increased incretins may improve bone density. However, these positive effects may be counterbalanced by the association between weight loss and a reduction in bone density. Finally, studies have shown a marked improvement following bariatric surgery in infertility and PCOS in women and hypogonadism in men. Thus, the net effect on endocrine systems after bariatric surgery will likely vary on an individual basis and depend on factors such as comorbidities, peri-menopausal state, amount of weight loss, and likelihood to adhere to vitamin supplementation after surgery.

Cytokine, Chemokine, and Cytokine Receptor Changes Are Associated With Metabolic Improvements After Bariatric Surgery

Context

Altered cytokine levels and chronic low-grade inflammation contribute to metabolic dysfunction in obesity. The extent of cytokine changes and their impact on metabolic improvements after bariatric surgery have not been fully explored.

Objective

To compare 76 circulating cytokines, chemokines, and secreted cytokine receptors in subjects with obesity and lean subjects and determine how these cytokines are altered by bariatric surgery.

Design, Setting, and Participants

A total of 37 patients with obesity and 37 lean patients in a cross-sectional study at an academic medical center. We also investigated cytokine changes in 25 patients with obesity after bariatric surgery.

Intervention

Bariatric surgery (Roux-en-Y gastric bypass and vertical sleeve gastrectomy).

Main Outcome Measures

Quantification of 76 circulating cytokines, chemokines, and secreted cytokine receptors.

Results

A total of 13 cytokines were significantly higher, and 4 lower, in patients with obesity relative to lean controls. Soluble vascular endothelial growth factor receptor 2 (sVEGFR2), soluble TNF receptor (sTNFR) 1, and sTNFR2 were positively correlated, and soluble receptor for advanced glycation end-products was inversely correlated, with weight and body mass index. sTNFR2 was positively correlated with fasting glucose, homeostatic model assessment of insulin resistance, and hemoglobin A1c. After bariatric surgery, adiponectin increased, and leptin decreased. Elevated sVEGFR2 levels in patients with obesity were decreased (P = 0.01), whereas reduced chemokine (C-X-C motif) ligand (CXCL) 12 levels in patients with obesity increased (P = 0.03) after surgery. Patients with higher soluble interleukin receptor (sIL) 1R2 and sIL-6R levels before surgery had greater weight loss after surgery (P < 0.05).

Conclusions

We demonstrate that chemokine (C-C motif) ligand (CCL) 14, sVEGFR2, and platelet-derived growth factor BB are elevated in obesity, and CXCL12, CCL11, and CCL27 are lower in obesity. We found clinically concordant directionality between lean and patients with obesity and before vs after surgery for six cytokines, suggesting that bariatric surgery shifted the cytokine profiles of patients with obesity toward that of lean controls.