Background Growing evidence suggests the key role of ghrelin in the onset and progression of nonalcoholic fatty liver disease (NAFLD). The potential participation of ghrelin and the ghrelin receptor antagonist, LEAP-2, in the onset of liver fibrosis in patients with severe obesity and NAFLD through the regulation of TGF-& beta;1-induced hepatic stellate cell (HSC) activation was investigated. Methods Circulating (n = 179) and hepatic expression (n = 95) of ghrelin and LEAP-2 were measured in patients with severe obesity and available liver pathology analysis undergoing Roux-en-Y gastric bypass (RYGB). The effect of ghrelin isoforms and LEAP-2 on TGF-& beta;1-induced HSC activation, fibrogenic response, and contractile properties was evaluated in vitro in human LX-2 cells. Results Plasma and hepatic ghrelin were negatively associated, while LEAP-2 exhibited a positive association with liver fibrosis in patients with obesity and NAFLD. Six months after RYGB, hepatic function was improved and, although acylated ghrelin and LEAP-2 concentrations remained unchanged, both hormones were inversely related to post-surgical levels of profibrogenic factors TGF-& beta;1 and TIMP-1. Acylated ghrelin treatment reversed TGF-& beta;1-induced myofibroblast-like phenotype, collagen contractile properties, and the upregulation of factors involved in HSC activation and fibrogenesis via PI3K/Akt/mTOR pathway. Moreover, acylated ghrelin inhibited the mild HSC activation induced by LEAP-2. Conclusions Ghrelin is an anti-fibrogenic factor blocking HSC activation induced by the most potent fibrogenic cytokine, TGF-& beta;1, and LEAP-2. The imbalance between acylated ghrelin and ghrelin receptor antagonist LEAP-2 might contribute to maintain liver fibrosis in patients with obesity and NAFLD.

Introduction: Obesity contributes to ectopic fat deposition in non-adipose organs, including the pancreas. Pancreas steatosis associates with inflammation and beta-cell dysfunction, contributing to the onset of insulin resistance and type 2 diabetes. An improvement of pancreatic steatosis and indices of insulin resistance is observed following bariatric surgery, but the underlying mechanisms remain unknown. We sought to analyze whether guanylin (GUCA2A) and uroguanylin (GUCA2B), two gut hormones involved in the regulation of satiety, food preference and adiposity, are involved in the amelioration of pancreas fat accumulation after bariatric surgery. Methods: Pancreas steatosis, inflammation, islet number and area were measured in male Wistar rats with diet-induced obesity (n=125) subjected to surgical (sham operation and sleeve gastrectomy) or dietary (pair-fed to the amount of food eaten by gastrectomized animals) interventions. The tissue distribution of guanylate cyclase C (GUCY2C) and the expression of the guanylin system were evaluated in rat pancreata by real-time PCR, Western-blot and immunohistochemistry. The effect of guanylin and uroguanylin on factors involved in insulin secretion and lipogenesis was determined in vitro in RIN-m5F beta-cells exposed to lipotoxic conditions. Results: Sleeve gastrectomy reduced pancreas steatosis and inflammation and improved insulin sensitivity and synthesis. An upregulation of GUCA2A and GUCY2C, but not GUCA2B, was observed in pancreata from rats with dietinduced obesity one month after sleeve gastrectomy. Interestingly, both guanylin and uroguanylin diminished the lipotoxicity in palmitate-treated RIN-m5F beta-cells, evidenced by lower steatosis and downregulated lipogenic factors Srebf1, Mogat2 and Dgat1. Both guanylin peptides reduced insulin synthesis (Ins1 and Ins2) and release from RIN-m5F beta-cells, but only guanylin upregulated Wnt4, a factor that controls beta-cell proliferation and function. Discussion: Together, sleeve gastrectomy reduced pancreatic steatosis and improved beta-cell function. Several mechanisms, including the modulation of inflammation and lipogenesis as well as the upregulation of GUCA2A in the pancreas, might explain this beneficial effect of bariatric surgery.

Objective p63 is a transcription factor within the p53 protein family that has key roles in development, differentiation and prevention of senescence, but its metabolic actions remain largely unknown. Herein, we investigated the physiological role of p63 in glucose metabolism. Design We used cell lines and mouse models to genetically manipulate p63 in hepatocytes. We also measured p63 in the liver of patients with obesity with or without type 2 diabetes (T2D). Results We show that hepatic p63 expression is reduced on fasting. Mice lacking the specific isoform TAp63 in the liver (p63LKO) display higher postprandial and pyruvate-induced glucose excursions. These mice have elevated SIRT1 levels, while SIRT1 knockdown in p63LKO mice normalises glycaemia. Overexpression of TAp63 in wild-type mice reduces postprandial, pyruvate-induced blood glucose and SIRT1 levels. Studies carried out in hepatocyte cell lines show that TAp63 regulates SIRT1 promoter by repressing its transcriptional activation. TAp63 also mediates the inhibitory effect of insulin on hepatic glucose production, as silencing TAp63 impairs insulin sensitivity. Finally, protein levels of TAp63 are reduced in obese persons with T2D and are negatively correlated with fasting glucose and homeostasis model assessment index. Conclusions. These results demonstrate that p63 physiologically regulates glucose homeostasis.

Glycerol is a key metabolite for lipid accumulation in insulin-sensitive tissues. We examined the role of aquaporin-7 (AQP7), the main glycerol channel in adipocytes, in the improvement of brown adipose tissue (BAT) whitening, a process whereby brown adipocytes differentiate into white like unilocular cells, after cold exposure or bariatric surgery in male Wistar rats with diet-induced obesity (DIO) (n = 229). DIO promoted BAT whitening, evidenced by increased BAT hypertrophy, steatosis and upregulation of the lipogenic factors Pparg2 , Mogat2 and Dgat1. AQP7 was detected in BAT capillary endothelial cells and brown adipocytes, and its expression was upregulated by DIO. Interestingly, AQP7 gene and protein expressions were downregulated after cold exposure (4( ?)C) for 1 week or one month after sleeve gastrectomy in parallel to the improvement of BAT whitening. Moreover, Aqp7 mRNA expression was positively associated with transcripts of the lipogenic factors Pparg2 , Mogat2 and Dgat1 and regulated by lipogenic (ghrelin) and lipolytic (isoproterenol and leptin) signals. Together, the upregulation of AQP7 in DIO might contribute to glycerol influx used for triacylglycerol synthesis in brown adipocytes, and hence, BAT whitening. This process is reversible by cold exposure and bariatric surgery, thereby suggesting the potential of targeting BAT AQP7 as an anti-obesity therapy.

Simple Summary Netrin-1 (NTN-1) regulates obesity-associated low-grade inflammation, being also involved in the control of cell migration and proliferation. We aim to study whether excess visceral adipose tissue in patients with obesity and colon cancer is associated with increased NTN1 and the expression levels of its main receptors, promoting an inflammatory microenvironment that favours colon cancer development. Increased expression levels of NTN1 and its receptor NEO1 in the visceral adipose tissue from patients with obesity and colon cancer together with elevated DCC and UNC5B mRNA levels in patients with colon cancer were found. Moreover, the treatment of colorectal cancer cells with NTN-1 and with the adipocyte-derived secretome obtained from patients with obesity increased the migration of colorectal cancer cells. These results suggest that NTN-1 plays an important role in obesity-associated colon cancer development. Netrin (NTN)-1, an extracellular matrix protein with a crucial role in inflammation, is dysregulated during obesity (OB) and influences colon cancer (CC) progression. To decipher the mechanisms underlying CC development during obesity, we examined the expression of NTN1 and its receptors in the visceral adipose tissue (VAT) of 74 (25 normal weight (NW)) (16 with CC) and 49 patients with OB (12 with CC). We also evaluated the effect of caloric restriction (CR) on the gene expression levels of Ntn1 and its receptors in the colon from a rat model fed a normal diet. The impact of adipocyte-conditioned media (ACM) from patients with OB and NTN-1 was assessed on the expression levels of neogenin 1(NEO1), deleted in colorectal carcinomas (DCC) and uncoordinated-5 homolog B (UNC5B) in Caco-2 and HT-29 human colorectal cell lines, as well as on Caco-2 cell migration. Increased NTN1 and NEO1 mRNA levels in VAT were due to OB (p < 0.05) and CC (p < 0.001). In addition, an upregulation in the expression levels of DCC and UNC5B in patients with CC (p < 0.01 and p < 0.05, respectively) was observed. Decreased (p < 0.01) Ntn1 levels in the colon from rats submitted to CR were found. In vitro experiments showed that ACM increased DCC (p < 0.05) and NEO1 (p < 0.01) mRNA levels in HT-29 and Caco-2 cell lines, respectively, while UNC5B decreased (p < 0.01) in HT-29. The treatment with NTN-1 increased (p < 0.05) NEO1 mRNA levels in HT-29 cells and DCC (p < 0.05) in both cell lines. Finally, we revealed a potent migratory effect of ACM and NTN-1 on Caco-2 cells. Collectively, these findings point to increased NTN-1 during OB and CC fuelling cancer progression and exerting a strong migratory effect on colon cancer cells.

Biological sex and aging impact obesity development and type 2 diabetes, changing the secretion of leptin and adiponectin. The balance between these factors has been propounded as a reliable biomarker of adipose tissue dysfunction. Our proposal was to study sexual differences and aging on the adiponectin/leptin (Adpn/Lep) ratio in order to acquire a broader view of the impact of consuming an high-fat diet (HFD) on energy metabolism according to sex and age. Male and female C57BL/6J mice were fed a normal chow diet or an HFD for 12 or 32 weeks (n = 7-10 per group) and evolution of body weight, food intake and metabolic profile were registered. The HFD triggered an increase in body weight (p < 0.001), body weight gain (p < 0.01) and adiposity index (p < 0.01) in both sexes at 32 weeks of age, but female mice fed the HFD exhibited these changes to a significantly lower extent than males. Aged female mice showed an increase (p < 0.01) in the Adpn/Lep ratio, which was negatively correlated with body weight gain, changes in different fat depots and insulin resistance. Females were more metabolically protected from obesity development and its related comorbidities than males regardless of age, making the Adpn/Lep ratio a relevant factor for body composition and glucose metabolism.

Biomechanical properties of adipose tissue (AT) are closely involved in the development of obesity associated comorbidities. Bariatric surgery (BS) constitutes the most effective option for a sustained weight loss in addition to improving obesity-associated metabolic diseases including type 2 diabetes (T2D). We aimed to determine the impact of weight loss achieved by BS and caloric restriction (CR) on the biomechanical properties of AT. BS but not CR changed the biomechanical properties of epididymal white AT (EWAT) from a diet-induced obesity rat model, which were associated with metabolic improvements. We found decreased gene expression levels of collagens and Lox together with increased elastin and Mmps mRNA levels in EWAT after BS, which were also associated with the biomechanical properties. Moreover, an increased blood vessel density was observed in EWAT after surgery, confirmed by an up regulation of Acta2 and Antxr1 gene expression levels, which was also correlated with the biomechanical properties. Visceral AT from patients with obesity showed increased stiffness after tensile tests compared to the EWAT from the animal model. This study uncovers new insights into EWAT adaptation after BS with decreased collagen crosslink and synthesis as well as an increased degradation together with enhanced blood vessel density providing, simultaneously, higher stiffness and more ductility. Statement of Significance Biomechanical properties of the adipose tissue (AT) are closely involved in the development of obesity associated comorbidities. In this study, we show for the first time that biomechanical properties of AT determined by E , UTS and strain at UTS are decreased in obesity, being increased after bariatric surgery by the promotion of ECM remodelling and neovascularization. Moreover, these changes in biomechanical properties are associated with improvements in metabolic homeostasis. Consistently, a better characterization of the plasticity and biomechanical properties of the AT after bariatric surgery opens up a new field for the development of innovative strategies for the reduction of fibrosis and inflammation in AT as well as to better understand obesity and its associated comorbidities.

Dysfunctional adipose tissue (AT) in the context of obesity leads to chronic inflammation together with an altered extracellular matrix (ECM) remodelling, favouring cancer development and progression. Recently, the influence of dermatopontin (DPT) in AT remodelling and inflammation has been proposed. We aimed to evaluate the role of DPT in the development of obesity-associated colon cancer (CC). Samples obtained from 73 subjects [26 lean (LN) and 47 with obesity (OB)] were used in a case-control study. Enrolled subjects were further subclassified according to the established diagnostic protocol for CC (42 without CC and 31 with CC). In vitro studies in the adenocarcinoma HT-29 cell line were performed to analyse the impact of pro- and anti-inflammatory mediators on the transcript levels of DPT as well as the effect of DPT on ECM remodelling and inflammation. Although obesity increased (p < 0.05) the circulating levels of DPT, its concentrations were significantly decreased (p < 0.05) in patients with CC. Gene expression levels of DPT in the colon from patients with CC were downregulated and, oppositely, a tendency towards increased mRNA levels in visceral AT was found. We further showed that DPT expression levels in HT-29 cells were enhanced (p < 0.05) by inflammatory factors (LPS, TNF-alpha and TGF-beta), whereas the anti-inflammatory IL-4 decreased (p < 0.05) its expression levels. We also demonstrated that DPT upregulated (p < 0.05) the mRNA of key molecules involved in ECM remodelling (COL1A1, COL5A3, TNC and VEGFA) whereas decorin (DCN) expression was downregulated (p < 0.05) in HT-29 cells. Finally, we revealed that the adipocyte-conditioned medium obtained from volunteers with OB enhanced (p < 0.01) the expression of DPT in HT-29 and Caco-2 cells. The decreased circulating and expression levels of DPT in the colon together with the tendency towards increased levels in visceral AT in patients with CC and its influence on the expression of ECM proteins suggest a possible role of DPT in the OB-associated CC.

Background: The biological mediators supporting long-term weight loss and changes in dietary choice behaviour after sleeve gastrectomy remain unclear. Guanylin and uroguanylin are gut hormones involved in the regulation of satiety, food preference and adiposity. Thus, we sought to analyze whether the guanylin system is involved in changes in food preference after sleeve gastrectomy in obesity. Methods: Proguanylin (GUCA2A) and prouroguanylin (GUCA2B) were determined in patients with severe obesity (n = 41) as well as in rats with diet-induced obesity (n = 48), monogenic obesity (Zucker fa/fa) (n = 18) or in a food choice paradigm (normal diet vs high-fat diet) (n = 16) submitted to sleeve gastrectomy. Lingual distribution and expression of guanylins (GUCA2A and GUCA2B) and their receptor GUCY2C as well as the fatty acid receptor CD36 were evaluated in the preclinical models. Results: Circulating concentrations of GUCA2A and GUCA2B were increased after sleeve gastrectomy in patients with severe obesity as well as in rats with diet-induced and monogenic (fa/fa) obesity. Interestingly, the lower dietary fat preference observed in obese rats under the food choice paradigm as well as in patients with obesity after sleeve gastrectomy were negatively associated with post-surgical GUCA2B levels. Moreover, sleeve gastrectomy upregulated the low expression of GUCA2A and GUCA2B in taste bud cells of tongues from rats with diet induced and monogenic (fa/fa) obesity in parallel to a downregulation of the lingual lipid sensor CD36. Conclusions: The increased circulating and lingual GUCA2B after sleeve gastrectomy suggest an association between the uroguanylin-GUCY2C endocrine axis and food preference through the regulation of gustatory responses. (c) 2022 Elsevier Inc. All rights reserved.