Marnie Granzotto

The mechanisms by which bariatric/metabolic surgery induces weight loss and the amelioration of obesity-associated complications are far from being fully elucidated. Variations in circulating hormones involved in the regulation of energy balance are usually considered to explain the effects of surgery beyond the restrictive mechanism. Recent studies have shown that gastric bypass modulates the plasma levels of GDF15, a molecule with anorectic action potentially contributing to the body weight reduction observed after surgery. Here, we report that sleeve gastrectomy has different effects on GDF15 plasma levels in patients with obesity depending on the presence of metabolic syndrome (MetS). Patients with MetS showed higher GDF15 plasma levels at baseline, but they had no increase in hormone concentrations compared to patients without MetS. Furthermore, at baseline, a correlation between blood glucose and GDF15 was observed in patients with MetS, and between plasma insulin and GDF15 in patients without MetS. Considering this data, GDF15 seems a molecule reflecting the severity of metabolic derangements not directly involved in mechanisms of surgical weight loss, and its role in obesity physiopathology and treatment needs to be further investigated.

Obesity is a systemic disease frequently associated with important complications such as type 2 diabetes and cardiovascular diseases. It has also been proven that obesity is a disease associated with chronic low-grade systemic inflammation and that weight loss improves this low-grade chronic inflammatory condition. The P2X7 purinergic receptor (P2X7R), belonging to the family of the receptors for extracellular ATP, is a main player in inflammation, activating inflammasome and pro-inflammatory cytokine production. In this study, we evaluated the plasma levels of soluble P2X7R (sP2X7R) measured in a group of obese patients before and one year after bariatric surgery. Furthermore, we evaluated the relation of sP2X7R to inflammatory marker plasma levels. We enrolled 15 obese patients who underwent laparoscopic sleeve gastrectomy, evaluating anthropometric parameters (weight, height, BMI and waist circumference) before and after surgery. Moreover, we measured the plasma levels of inflammatory markers (CRP, TNFα and IL-6) before and after weight loss via bariatric surgery. The results of our study show that one year after bariatric surgery, obese patients significantly decrease body weight with a significant decrease in CRP, TNF-alfa and IL-6 plasma levels. Similarly, after weight loss, obese subjects showed a significant reduction in sP2X7R plasma levels. Moreover, before surgery, plasma levels of sP2X7R were inversely related with those of CRP, TNF-alfa and IL-6. Given the role of P2X7R in inflammation, we hypothesized that, in obese subjects, sP2X7R could represent a possible marker of chronic low-grade inflammation, hypothesizing a possible role as a mediator of obesity complications.

Purpose: Psoriasis is a chronic systemic inflammatory disease involving the production of many pro-inflammatory cytokines derived from immune cells and interacting with different tissues leading to the typical skin lesions. Psoriasis shows a higher prevalence and a worse progression in obese than in lean subjects. The IL-23/IL-17 immune axis has a pivotal role in the pathogenesis of psoriasis and anti-IL-23 monoclonal antibodies are highly effective in its treatment. Since obesity in frequently associated with elevated insulin plasma levels, we have investigated the ability of in vitro differentiated human adipocytes to produce IL-23 at basal conditions and after insulin stimulation. Material and Methods: In vitro differentiated human adipocytes were incubated in the absence and presence of different insulin concentrations and the expression of IL-23 was analyzed by real-time PCR and Western blotting. Results: The results of this study show that in vitro differentiated human adipocytes spontaneously express IL-23 mRNA and protein being stimulated by insulin in a dose-dependent manner. The stimulatory effects of insulin on IL-23 expression were specific since it did not stimulate the expression of other well-known cytokines involved in psoriasis pathogenesis such as Il-22 nor LL-37. Furthermore, lipopolysaccharide did not stimulate IL-23 expression in human adipocytes, thus highlightening the specific effects of insulin in the stimulation of IL-23 expression in human adipocytes. Conclusion: Here we show that human adipocytes spontaneously express IL-23 and that insulin stimulates IL-23 production by these cells in a specific manner as other stimuli, known to be involved in psoriasis pathophysiology, are ineffective. These observations could explain the association between psoriasis and obesity, a condition frequently characterized by a state of insulin hypersecretion.

Insulin-like factor 5 (INSL5), a novel hormone secreted by the enteroendocrine cells of the distal colon, has been implicated in appetite and body weight regulation in animals given its orexigenic properties. We investigated basal INSL5 plasma levels in a group of morbidly obese subjects before and after laparoscopic sleeve gastrectomy. Furthermore, we analyzed the expression of INSL5 in human adipose tissue. Before bariatric surgery, obese subjects showed basal INSL5 plasma levels that were positively correlated with BMI, fat mass, and leptin plasma levels. After weight loss by laparoscopic sleeve gastrectomy, INSL5 plasma levels in obese subjects were significantly lower than those observed before surgery. Finally, we did not detect any expression of the INSL5 gene in human adipose tissue, both at the mRNA and protein levels. The present data show that subjects with obesity have INSL5 plasma levels positively correlating with adiposity markers. After bariatric surgery, INSL5 plasma levels decreased significantly, and this decrease was not directly due to the loss of adipose tissue since this tissue does not express INSL5. Considering the orexigenic properties of INSL5, the reduction of its plasma levels after bariatric surgery in obese subjects could participate in the still unclear mechanisms leading to appetite reduction that characterize bariatric surgery procedures.

Background: The development of obesity-related complications lies in the low-grade inflammatory state consequent to adipocyte dysfunction. The direct involvement of sex hormones in adipose tissue inflammation has been previously suggested, but the evidence is scarce. In this study, we evaluated the effects of sex steroids on the in-vitroexpression of inflammatory mediators in human-derived adipocytes before and after lipopolysaccharide (LPS) exposure. Methods: Human adipocytes were differentiated from the vascular stromal fraction of adipose tissue samples of subjects undergoing abdominoplasty. We evaluated MCP-1, IL-1β, IL-6, and TNF-α gene expression in the presence of the main sex steroids, testosterone (T), and 17β-estradiol (E). Furthermore, we analyzed the effects of adipocytes exposure to the non-aromatizable androgen dihydrotestosterone (DHT), together with the effects of adipocytes pre-incubation with the aromatase inhibitor anastrozole alone (A), and in combination with T (A/T) before incubation with LPS. Results: DHT, but not T, significantly enhanced the LPSinduction of MCP-1, IL-1β, IL-6, and TNF-α. Intriguingly, the exposure of adipocytes with A/T dramatically increased the LPS-induced expression of all considered inflammatory cytokines, even more than a hundred-fold. Conclusions: DHT and A/T dramatically enhance LPS-induced inflammatory cytokine expression in human-derived adipocytes. These results confirm the involvement of sex hormones in adipose tissue inflammation, suggesting a specific role for non-aromatizable androgens as the amplificatory sex hormones of the inflammatory response.

Extracellular ATP exerts important functions as an extracellular signaling molecule via the activation of specific P2 purinergic receptors (P2X and P2Y). We investigated the expression of the different P2 receptors and their possible functional activation in human adipocytes in primary culture. We performed molecular expression analysis of the P2 receptors in human mature adipocytes; examined their functional activation by different nucleotides evaluating [Ca²⁺]_i modifications and IL-6 secretion, and determined the ability of adipocytes to release ATP in the extracellular medium. Human adipocytes express different P2X and P2Y receptors. Extracellular ATP elicited a rise in [Ca²⁺]_i via the activation of P2X and P2Y receptor subtypes. Human adipocytes spontaneously released ATP in the extracellular medium and secreted IL-6 both at rest and after stimulation with ATP. This stimulatory effect of ATP on IL-6 secretion was inhibited by pre-incubation with apyrase, an ATP metabolizing enzyme. These results demonstrate that human adipocytes express different P2X and P2Y receptors that are functionally activated by extracellular nucleotides. Furthermore, human adipocytes spontaneously release ATP, which can act in an autocrine/paracrine fashion on adipocytes, possibly participating in the regulation of inflammatory cytokine release. Thus, P2 purinergic receptors could be a potential therapeutic target to contrast the inflammatory and metabolic complications characterizing obesity.

Osteoarthritis (OA) is one of the most common joint disorders. Evidence suggests that the infrapatellar fat pad (IFP) is directly involved in OA pathology. However, a comparison between OA versus non-OA IFP is still missing. Thus, the aim of this study was to compare IFP molecular, adipocytes and extracellular matrix characteristics of patients affected by OA, and patients undergoing anterior cruciate ligament (ACL) reconstruction. We hypothesized that not only inflammation but also changes in adipocytes and extracellular matrix (ECM) composition might be involved in OA pathogenesis. Fifty-three patients were enrolled. IFP biopsies were obtained, evaluating: (a) lymphocytic infiltration and vascularization; (b) adipocytes area and number; (c) adipo-cytokines and extracellular matrix gene expression levels; (d) IL-6 and VEGF protein production; (e) collagen fibers distribution. OA IFP was more inflamed and vascularized compared to ACL IFP. OA IFP adipocytes were larger and numerically lower (1.3-fold) than ACL IFP adipocytes. An increase of gene expression of typical white adipose tissue genes was observed in OA compared to ACL IFP. Collagen-types distribution was different in the OA IFP group compared to controls, possibly explaining the change of the biomechanical characteristics found in OA IFP. Statistical linear models revealed that the adipocyte area correlated with BMI in the OA group. In conclusion, inflammation and fibrotic changes of OA IFP could represent novel therapeutic targets to counteract OA.

AIM: Cold exposure and exercise may increase thermogenic capacity of white adipose tissue (WAT), which could subsequently enhance energy expenditure and body weight loss. We aimed to identify possible alterations in uncoupling protein 1 (UCP1)—the main biomarker of thermogenic activation—in human WAT due to both cold exposure and exercise, as well as the link between environmental temperature and thermogenic capacity of human WAT. MATERIAL & METHOD: We conducted four human experimental studies and two systematic reviews and meta-analyses—PROSPERO registration CRD42019120116, CRD42019120213. RESULTS: UCP1 mRNA was higher in winter than in summer [t(30) = 2.232, p = 0.03] in human WAT and our meta-analysis showed a main effect of cold exposure on human UCP1 mRNA [standard mean difference (Std-md) = 1.81, confidence interval (CI) = 0.50–3.13, p = 0.007]. However, UCP1 mRNA/protein expressions displayed no associations with %fat mass or BMI (p > 0.05, Cohen’s f² < 0.20). Both a 2-hour cooling and a non-cooling protocol preceding the positron emission tomography/computed tomography (PET/CT) measurements revealed no association between environmental temperature and standardised uptake value (SUVmax) of human WAT, as well as no mean differences in SUVmax-WAT-activity between winter and summer. An 8-week exercise program had no effect on UCP1 of human WAT or on body composition. Our meta-analysis also revealed: (a) no effect of chronic exercise on human UCP1 mRNA, (b) a main effect of chronic exercise on UCP1 protein concentrations (Std-md = 0.59, CI = 0.03–1.16, p = 0.04) and UCP1 mRNA (Std-md = 1.76, CI = 0.48–3.04, p = 0.007) in WAT of normal diet animals, c) a main effect of chronic exercise on UCP1 mRNA (Std-md = 2.94, CI = 0.24–5.65, p = 0.03) and UCP1 protein concentrations (Std-md = 2.06, CI = 0.07–4.05, p = 0.04) of high-fat diet animals. CONCLUSIONS: Cold exposure represents a main stimulus for increased thermogenic capacity in human white adipocytes; however, this may have no impact on body weight loss. Chronic exercise may represent no major stimulus for UCP1 induced in human white adipocytes, while in animals it increases UCP1 gene independently of their diet. Therefore, evidence from animal studies regarding UCP1 gene activation in white adipocytes may not be applicable in humans. Finally, the identification of human WAT thermogenic capacity via PET/CT examination may be optimal with both a cooling and a non-cooling protocol.

Abstract We report the case of a 15-year-old woman with signs of hyperandrogenism affected by a Sertoli–Leydig cell tumor (SLCT). In our patient, blood analysis showed a high testosterone (T) level (T: 8.53 nmol/L; nv < 1.87 nmol/L) while the GnRH-analogue test demonstrated an exaggerated secretion of 17-hydroxyprogesterone (OHP), T, and androstenedione (A) by the ovary after stimulation. We compared the GnRH-analogue test of our patient with that obtained in a group of normal and healthy women (no. 8 subjects, 16–26 years old), men (no. 4 subjects, 18–28 years old), and in a group of PCOS patients with age and body weight compared. We found in our patient a value of OHP, 17-beta estradiol (E₂) and T, from 2 to 18 times higher than healthy women. When we compared our patient with healthy men, we differently observed a comparable response of T. The response of our patient was also comparable with that observed in the PCOS group for E₂. During the post-surgical follow up, the GnRH-analogue test of our patient showed a response of OHP, T, and E₂ comparable with that of the PCOS group. The GnRH-analogue test is a useful tool to characterize steroidogenesis in SLCT. Chinese abstract 摘要 今天我们报道一例以高雄激素血症为特征的15岁的支持–睾丸间质细胞瘤（SLCT）个案。该患者血液化验提示睾酮升高，促性腺激素释放激素试验提示卵巢经刺激后分泌17-羟孕酮、睾酮、雄烯二酮升高。我们在患者、正常健康妇女、正常健康男性、多囊卵巢综合征患者间进行促性腺激素释放激素试验的比较。我们发现患者的17-羟孕酮、雌二醇、睾酮高于健康女性2-18倍。我们将患者和正常男性进行比较，发现对睾酮的反应不同。也观察了患者和多囊卵巢综合征患者对雌二醇的反应。在术后随访中，患者和多囊卵巢综合征患者的17-羟孕酮、睾酮、雌二醇的反应一致。促性腺激素释放激素类似物试验是测定支持–睾丸间质细胞瘤患者类固醇的一个有用的工具。