Cocaine and amphetamine regulated transcript and brain-derived neurotrophic factor in morbid obesity. One-year follow-up after gastric bypass

Prospective Study on the Correlation between CART and Leptin Gene Expression, Obesity, and Reproductive Hormones in Individuals Undergoing Bariatric Surgery

Obesity, a global health concern affecting 650 million individuals of all ages worldwide, prompts health complications, including fertility issues. This research investigates the impact of bariatric surgery on morbidly obese females under 40, examining the relationship between CART and leptin gene expressions and reproductive hormones. Post-surgery, a significant reduction in BMI (16.03 kg/m2, n = 29) was observed, accompanied by notable hormonal changes. FSH levels showed a mean difference of 3.18 ± 1.19 pre- and post-surgery (p < 0.001), LH levels exhibited a mean difference of 2.62 ± 1.1 (p < 0.001), E2 levels demonstrated a mean difference of 18.62 ± 5.02 (p < 0.001), and AMH levels showed a mean difference of 3.18 ± 1.19 (p < 0.001). High CART and leptin expressions before treatment correlated with lower expressions after treatment. These findings, rooted in statistically significant correlations (CART: rs = 0.51, p = 0.005; leptin: rs = 0.75, p < 0.001), shed light on potential molecular pathways connecting gene expressions with reproductive hormones post-bariatric surgery. Our study uniquely investigates the interplay between genetic markers, infertility, and bariatric surgery in women. It stands out by providing distinctive insights into the development of personalized treatment strategies for obesity-related infertility, contributing to a deeper understanding of this complex medical issue.

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/).

Effects of Peripheral Neural Blocks in Laparoscopic Sleeve Gastrectomy: a Pilot Study on Cognitive Functions in Severe Obese Patients

BACKGROUND

In addition to the analgesic effect, peripheral neural blocks also prevent cognitive impairment and peripheral inflammation induced by surgery. However, it is unknown if there is collateral impact on cognitive improvement after bariatric surgery.

METHODS

In this pilot study, 75 patients with severe obesity for selective laparoscopic sleeve gastrectomy (LSG) were recruited and randomized into three groups (1:1:1) as general anesthesia (GA) group, transverse abdominis plane block (TAPB) group, and quadratus lumborum block (QLB) group. Bilateral TAPB or QLB was performed (0.33% ropivacaine with dexmedetomidine 1 μg/kg) before the standardized general anesthesia. Cognitive test battery was completed before LSG and in 1-month and 3-month follow-up. The levels of peripheral inflammatory cytokines were determined at equivalent time points.

RESULTS

Patients with LSG exhibited massive cognitive improvement in postoperative 3 month without or with TAPB or QLB (P_time < 0.001). Compared to GA, QLB significantly strengthened performance in MoCA (β = 0.56, 95%CI: 0.08, 1.05). IL-6, IL-8, and high-sensitivity CRP significantly verified among three groups. Changes in IL-6 within postoperative 3 months were negatively correlated with MMSE and MoCA, and positively correlated with AVLT-DR for QLB group. Similar correlation was found in the GA group for changes in IL-6 and AVLT-IR.

CONCLUSION

Laparoscopic sleeve gastrectomy ideally improved memory and attention as early as postoperative 1 month. QLB promoted cognitive improvement in MoCA, which was negatively correlated with changes in IL-6. More precise trials are needed to determine the overall effect of peripheral neural block on cognition following bariatric surgery.

Metabolic adaptations after bariatric surgery: adipokines, myokines and hepatokines

This review addresses the impact of bariatric surgery on the endocrine aspects of white adipose tissue, muscle and the liver. We describe literature supporting the notion that adipokines, myokines and hepatokines likely act in concert and drive many of the long-term metabolic improvements following surgery. Circulating adiponectin is increased while secretion of pro-inflammatory interleukins (1, 6 and 8) decreases, alongside leptin secretion. The metabolic improvements observed in the muscle might relate to reduction of myokines contributing to insulin resistance (including myostatin, brain-derived neurotrophic factor and fibroblast growth factor-21). Subject to exception, hepatokine secretion is generally increased (such as insulin-like growth factor-binding protein 2, adropin and sex hormone-binding globulin). In conclusion, bariatric surgery restores metabolic functions by enhancing the time-dependent secretion of anti-inflammatory, insulin-sensitizing and antilipemic factors. Further research is needed to understand the molecular mechanisms by which these factors may trigger the remission of obesity-related comorbidities following bariatric surgery.

Circulating Diabetic Candidate Neurotrophic Factors, Brain-Derived Neurotrophic Factor and Fibroblast Growth Factor 21, in Sleeve Gastrectomy

Recent studies show brain-derived neurotrophic factor (BDNF) and fibroblast growth factor 21 (FGF21) are neurotrophic factors associated with obesity and diabetes mellitus (DM). Laparoscopic sleeve gastrectomy (LSG) can significantly reduce weight and improve DM. In this study, we enrolled 78 patients with obesity and evaluated the change of BDNF and FGF21 6 months after LSG. At baseline, the BDNF level was similar between the preoperative DM (n = 30) (17.1 ± 7.7 ng/ml) and non-DM (n = 48) (17.0 ± 6.9 ng/ml) patients with obesity, but FGF21 was significantly higher in the DM patients (201.5 ± 204.3 versus 107.6 ± 63.8 pg/ml). At 6 months after LSG, most of the preoperative DM patients (96.7%) had DM either resolved (66.7%) or improved (30%). BDNF increased and FGF21 decreased significantly regardless of the preoperative DM status, while FGF21 decreased more prominently in the preoperative DM patients (-92.6 ± 179.8 versus -4.6 ± 63.4 pg/ml). After adjusted for age, sex, and preoperative DM status, FGF21 became significantly and positively related to C-peptide (β = 18.887), insulin (β = 2.399), and homeostasis model assessment of insulin resistance index (β = 8.566) after surgery. In conclusion, diabetic patients with obesity had higher FGF21 and similar BDNF levels compared to non-diabetic obese patients. BDNF increased and FGF21 decreased significantly after LSG. FGF21 became positively associated with several insulin-related profiles after surgery.

Mitogen-Activated Protein Kinase (MAPK) and Obesity-Related Cancer

Obesity is a major public health concern worldwide. The increased risk of certain types of cancer is now an established deleterious consequence of obesity, although the molecular mechanisms of this are not completely understood. In this review, we aim to explore the links between MAPK signalling and obesity-related cancer. We focus mostly on p38 and JNK MAPK, as the role of ERK remains unclear. These links are seen through the implication of MAPK in obesity-related immune paralysis as well as through effects on the endoplasmic reticulum stress response and activation of aromatase. By way of example, we highlight areas of interest and possibilities for future research in endometrioid endometrial cancer and hepatocellular carcinoma associated with non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH) and MAPK.

The Neuroendocrine and Metabolic Outcomes of Bariatric Surgery Depend on Presurgical Control over Eating

BACKGROUND

The outcomes of bariatric surgery are very irregular and mostly unpredictable. The search for variables of predictive value is encouraged to help preventing therapeutic failures.

OBJECTIVE

We aimed to confirm the hypothesis that preexisting eating behaviors could predict neuroendocrine and metabolic outcomes of gastric bypass surgery in morbidly obese subjects.

METHODS

Twenty-one morbidly obese patients from the Bariatric Surgery Program of our hospital were selected according to the specific inclusion and exclusion criteria for this study. The subjects filled out a validated questionnaire to quantify the "loss-of-control" (LC) dimension of food craving and provided serum samples at the onset of the study and 1 year after gastric bypass surgery. Hematological, metabolic, and hormonal variables were studied by conventional clinical tests and enzyme immunoassays and checked for correlations with LC both before and after surgery.

RESULTS

Those patients that had exhibited worse eating control at the beginning of the study experienced a better metabolic response 1 year after surgery in terms of reduction of serum insulin, HOMA1-IR, HOMA2-IR, and vitamin D1; all these variables were inversely correlated with presurgical LC. Serum brain-derived neurotrophic factor (BDNF) levels showed the same tendency; in fact, BDNF significantly decreased only in those patients with worse eating control.

CONCLUSIONS

Problematic eating behaviors may predict a better response of insulin resistance and a specific reduction of serum BDNF in morbidly obese patients after gastric bypass surgery.

Fish as models for understanding the vertebrate endocrine regulation of feeding and weight

The frequencies of eating disorders and obesity have increased worldwide in recent years. Their pathophysiologies are still unclear, but recent evidence suggests that they might be related to changes in endocrine and neural factors that regulate feeding and energy homeostasis. In order to develop efficient therapeutic drugs, a more thorough knowledge of the neuronal circuits and mechanisms involved is needed. Although to date, rodents have mostly been used models in the area of neuroscience and neuroendocrinology, an increasing number of studies use non-mammalian vertebrates, in particular fish, as model systems. Fish present several advantages over mammalian models and they share genetic and physiological homology to mammals with close similarities in the mechanisms involved in the neural and endocrine regulation of appetite. This review briefly describes the regulation of feeding in two model species, goldfish and zebrafish, how this regulation compares to that in mammals, and how these fish could be used for studies on endocrine regulation of eating and weight and its dysregulations.

Proteomic Identification of Biomarkers Associated with Eating Control and Bariatric Surgery Outcomes in Patients with Morbid Obesity

BACKGROUND

The current therapeutics of morbid obesity could be significantly improved after the identification of novel biomarkers associated with the food addiction endophenotype of obesity and with bariatric surgery outcomes.

METHODS

We applied differential expression proteomics and enzyme-linked immunosorbent confirmatory assays to identify (a) proteins that varied according to loss of control over eating in morbidly obese patients and (b) proteins that varied between normoweight controls and patients before and 1 year after bariatric surgery.

RESULTS

Clusterin was the only protein that consistently varied according to eating control in patients. Patients showed increased levels of serum amyloid P protein, apolipoprotein A4, serotransferrin, complement factors B and C3 and haptoglobin with respect to controls; the levels of all these proteins tended to return to control values 1 year after surgery. In contrast, apolipoprotein A1 and transthyretin were initially downregulated in patients and were scarcely changed by surgery. Leucine-rich alpha-2-glycoprotein was markedly increased in patients only after surgery.

CONCLUSIONS

Clusterin could be of interest as a putative biomarker for food addiction diagnosis in people with morbid obesity. In addition, postsurgical normalization of the proteins initially dysregulated in obese subjects might help monitor clinical improvements after surgery, while lasting or newly detected alterations (i.e., those affecting transthyretin and leucine-rich alpha-2-glycoprotein) could reflect partial refractoriness and/or contribute to the early prediction of clinical problems.