Daniela Gentile

The involvement of purinergic signalling in obesity

Obesity is a growing worldwide health problem, with an alarming increasing prevalence in developed countries, caused by a dysregulation of energy balance. Currently, no wholly successful pharmacological treatments are available for obesity and related adverse consequences. In recent years, hints obtained from several experimental animal models support the notion that purinergic signalling, acting through ATP-gated ion channels (P2X), G protein-coupled receptors (P2Y) and adenosine receptors (P1), is involved in obesity, both at peripheral and central levels. This review has drawn together, for the first time, the evidence for a promising, much needed novel therapeutic purinergic signalling approach for the treatment of obesity with a ‘proof of concept’ that hopefully could lead to further investigations and clinical trials for the management of obesity.

Effects of L-DOPA/benserazide co-treatment on colonic excitatory cholinergic motility and enteric inflammation following dopaminergic nigrostriatal neurodegeneration

Introduction: The mainstay therapy for Parkinsons disease (PD) relies on L‐3,4‐dihydroxyphenylalanine (L‐DOPA) plus a DOPA‐decarboxylase inhibitor. However, their effects on colonic dysmotility and inflammation observed in PD are undetermined. This study examined the effects of L‐DOPA plus benserazide (BE) on colonic motility and inflammation in rats with central nigrostriatal dopaminergic denervation. Methods: Neurodegeneration was induced by 6‐hydroxydopamine (6‐OHDA) injection into the medial forebrain bundle (MFB). 6‐OHDA animals were treated orally with L‐DOPA/BE for 28 days, starting 28 days after 6‐OHDA injection. At the end of treatment, in vivo colonic transit was evaluated by a radiologic assay. Electrically stimulated (ES) cholinergic contractions were recorded in vitro from colonic preparations, while acetylcholine release was measured in the incubation medium. Choline acetyltransferase (ChAT) and glial fibrillary acidic protein (GFAP) expression as well as eosinophil and mast cell density were examined in the colonic wall by immunohistochemistry. Colonic TNF and IL‐1&bgr; levels were also assayed. Results: 6‐OHDA animals displayed: 1) decrease in in vivo colonic transit; 2) impairment of ES‐stimulated cholinergic contractions; 3) decreased acetylcholine release from myenteric nerves; 4) decrease in ChAT and increase in GFAP myenteric immunopositivity; 5) increase in eosinophil and mast cell density; 6) increase in TNF and IL‐1&bgr; levels. Treatment with L‐DOPA/BE elicited an improvement of in vivo and in vitro colonic motor activity, a normalization of acetylcholine release, ChAT immunopositivity, as well as pro‐inflammatory cytokine patterns, ganglionic GFAP levels, eosinophil and mast cell density. Conclusion: Under dopaminergic nigrostriatal denervation, treatment with L‐DOPA/BE ameliorated colonic motility through a normalization of myenteric cholinergic neurotransmission, along with an improvement of colonic inflammation. HighlightsL‐DOPA effects on colonic dysfunctions in 6‐OHDA rats are evaluated.L‐DOPA administration restores colonic in vivo transit and in vitro contractility.L‐DOPA treatment normalizes colonic cholinergic neurotransmission in 6‐OHDA rats.L‐DOPA improves colonic inflammation associated with central dopaminergic denervation.

Dietary flavonoids as a potential intervention to improve redox balance in obesity and related co-morbidities: a review

Obesity represents one of major health problems strongly linked to other co-morbidities, such as type 2 diabetes, CVD, gastrointestinal disorders and cognitive impairment. In this context, nutritional stress, such as an excess of fat intake, promotes a systemic oxidative stress, characterised by hyperproduction of reactive oxygen species, leading to cellular alterations that include impaired energy metabolism, altered cell signalling and cell cycle control, impaired cell transport mechanisms and overall dysfunctional biological activity. Flavonoids, dietary components of plant foods, are endowed with a wide spectrum of biological activities, including antioxidant activity, and have been proposed to reduce the risk of major chronic diseases. The present review intends to highlight and critically discuss the current scientific evidence on the possible effects of flavonoids in counteracting obesity and related co-morbidities (i.e. type 2 diabetes mellitus, CVD, gastrointestinal disorders and cognitive impairment) through a decrease in oxidative stress and related inflammatory conditions.

Colonic Dysmotility Associated with High Fat Diet-Induced Obesity: Role of the Enteric Glia

Interplay between colonic inflammation and tachykininergic pathways in the onset of colonic dysmotility in a mouse model of diet-induced obesity Antonioli, Luca; Caputi, Valentina; Fornai, Matteo; Pellegrini, Carolina; Gentile, Daniela; Giron, Maria Cecilia; Orso, Genny; Bernardini, Nunzia; Segnani, Cristina; Ippolito, Chiara; Csóka, Balázs; Haskó, György; Németh, Zoltán H.; Scarpignato, Carmelo; Blandizzi, Corrado; Colucci, Rocchina 2019

The flavonoid compound apigenin prevents colonic inflammation and motor dysfunctions associated with high fat diet-induced obesity

Background and purpose Apigenin can exert beneficial actions in the prevention of obesity. However, its putative action on obesity-associated bowel motor dysfunctions is unknown. This study examined the effects of apigenin on colonic inflammatory and motor abnormalities in a mouse model of diet-induced obesity. Experimental approach Male C57BL/6J mice were fed with standard diet (SD) or high-fat diet (HFD). SD or HFD mice were treated with apigenin (10 mg/Kg/day). After 8 weeks, body and epididymal fat weight, as well as cholesterol, triglycerides and glucose levels were evaluated. Malondialdehyde (MDA), IL-1β and IL-6 levels, and let-7f expression were also examined. Colonic infiltration by eosinophils, as well as substance P (SP) and inducible nitric oxide synthase (iNOS) expressions were evaluated. Motor responses elicited under blockade of NOS and tachykininergic contractions were recorded in vitro from colonic longitudinal muscle preparations. Key results When compared to SD mice, HFD animals displayed increased body weight, epididymal fat weight and metabolic indexes. HFD mice showed increments in colonic MDA, IL-1β and IL-6 levels, as well as a decrease in let-7f expression in both colonic and epididymal tissues. HFD mice displayed an increase in colonic eosinophil infiltration. Immunohistochemistry revealed an increase in SP and iNOS expression in myenteric ganglia of HFD mice. In preparations from HFD mice, electrically evoked contractions upon NOS blockade or mediated by tachykininergic stimulation were enhanced. In HFD mice, Apigenin counteracted the increase in body and epididymal fat weight, as well as the alterations of metabolic indexes. Apigenin reduced also MDA, IL-1β and IL-6 colonic levels as well as eosinophil infiltration, SP and iNOS expression, along with a normalization of electrically evoked tachykininergic and nitrergic contractions. In addition, apigenin normalized let-7f expression in epididymal fat tissues, but not in colonic specimens. Conclusions and implications Apigenin prevents systemic metabolic alterations, counteracts enteric inflammation and normalizes colonic dysmotility associated with obesity.

Interplay between colonic inflammation and tachykininergic pathways in the onset of colonic dysmotility in a mouse model of diet-induced obesity

BackgroundThe murine model of high fat diet (HFD)-induced obesity is characterized by an increment of intestinal permeability, secondary to an impairment of mucosal epithelial barrier and enteric inflammation, followed by morphofunctional rearrangement of the enteric nervous system. The present study investigated the involvement of abdominal macrophages in the mechanisms underlying the development of enteric dysmotility associated with obesity.MethodsWild type C57BL/6J mice were fed with HFD (60% kcal from fat) or normocaloric diet (NCD, 18% kcal from fat) for 8 weeks. Groups of mice fed with NCD or HFD were treated with clodronate encapsulated into liposomes to deplete abdominal macrophages. Tachykininergic contractions, elicited by electrical stimulation or exogenous substance P (SP), were recorded in vitro from longitudinal muscle colonic preparations. Substance P distribution was examined by confocal immunohistochemistry. The density of macrophages in the colonic wall was examined by immunohistochemical analysis. Malondialdehyde (MDA, colorimetric assay) and IL-1β (ELISA assay) levels were also evaluated.ResultsMDA and IL-1β levels were increased in colonic tissues from HFD-treated animals. In colonic preparations, electrically evoked tachykininergic contractions were enhanced in HFD mice. Immunohistochemistry displayed an increase in substance P immunoreactivity in myenteric ganglia, as well as in the muscular layers of colonic cryosections from obese mice. Macrophage depletion in HFD mice was associated with a significant reduction of colonic inflammation. In addition, the decrease in macrophage density attenuated the morphofunctional alterations of tachykininergic pathways observed in obese mice.ConclusionObesity elicited by HFD determines a condition of colonic inflammation, followed by a marked rearrangement of motor excitatory tachykininergic enteric nerves. Macrophage depletion counteracted the morphofunctional changes of colonic neuromuscular compartment, suggesting a critical role for these immune cells in the onset of enteric dysmotility associated with obesity.

Luteolin Prevents Cardiometabolic Alterations and Vascular Dysfunction in Mice With HFD-Induced Obesity

Purpose: Luteolin exerts beneficial effects against obesity-associated comorbidities, although its influence on vascular dysfunction remains undetermined. We examined the effects of luteolin on endothelial dysfunction in a mouse model of diet-induced obesity. Methods: Standard diet (SD) or high-fat diet (HFD)-fed mice were treated daily with luteolin intragastrically. After 8 weeks, body and epididymal fat weight, as well as blood cholesterol, glucose, and triglycerides were evaluated. Endothelium-dependent relaxations of resistance mesenteric vessels was assessed by a concentration-response curve to acetylcholine, repeated upon Nw-nitro-L-arginine methylester (L-NAME) or ascorbic acid infusion to investigate the influence of nitric oxide (NO) availability and reactive oxygen species (ROS) on endothelial function, respectively. Intravascular ROS production and TNF levels were measured by dihydroethidium dye and ELISA, respectively. Endothelial NO synthase (eNOS) and superoxide dismutase 1 (SOD1), as well as microRNA-214-3p expression were examined by Western blot and RT-PCR assays, respectively. Results: HFD animals displayed elevated body weight, epididymal fat weight and metabolic indexes. Endothelium-dependent relaxation was resistant to L-NAME and enhanced by ascorbic acid, which restored also the inhibitory effect of L-NAME, suggesting a ROS-dependent reduction of NO availability in HFD vessels. Moreover, media-lumen ratio, intravascular superoxide anion and TNF levels were increased, while vascular eNOS, SOD1, and microRNA-214-3p expression were decreased. In HFD mice, luteolin counteracted the increase in body and epididymal fat weight, and metabolic alterations. Luteolin restored vascular endothelial NO availability, normalized the media-lumen ratio, decreased ROS and TNF levels, and normalized eNOS, SOD1 and microRNA-214-3p expression. Conclusion: Luteolin prevents systemic metabolic alterations and vascular dysfunction associated with obesity, likely through antioxidant and anti-inflammatory mechanisms.

Histomorphological analysis of the colonic barrier in a mouse model of obesity

Background and Aim. Obesity is a metabolic disorder with an increasing incidence in Western countries and childhood. It is characterized by low-grade systemic inflammation and several comorbidities, including alterations of gastrointestinal (GI) functions, which impact negatively on patients’ quality of life. There is currently limited information on the morpho-functional features of the GI tract in obese subjects. Of note, the intestinal barrier function has been found to be altered in obese subjects, even before the occurrence of body weight increase [1]. In this light, the present study was carried out to assess, in a mouse model of diet-induced obesity, whether high fat diet (HFD) is associated with morphological alterations of the colonic mucosal barrier. Methods. C57BL/6 mice (n=5/group) were fed with standard diet (SD, 18% calories from fat) or HFD (60% calories from fat). After 8 weeks, body weight, and levels of blood cholesterol, triglycerides and glucose were evaluated. Malondialdehyde (MDA, colorimetric assay), IL-1β and IL-6 levels (ELISA assays) were examined in colonic tissues. Morphological features of colonic mucosal structures (lining epithelial cells, goblet cells, inflammatory infiltrates and enteric glia) were examined by histochemistry and immunohistochemistry. Results. HFD mice displayed significant differences at both molecular and histomorphological level, as compared with SD animals: increased body weight and blood metabolic indexes; increased MDA, IL-1β and IL-6 levels in colonic tissues; altered pattern of claudin-1 expression along with upregulation of transmembrane 16A protein and induced nitric oxide synthase in the enteric epithelium facing the lumen; increased proliferation rate of crypts; altered composition of goblet cell mucous; mucosal gliosis and infiltrates with mixed inflammatory cells. Conclusions. After 8 weeks, HFD intake led to significant alterations of systemic metabolic indexes, colonic tissue inflammation, and colonic mucosal barrier in obese mice, as compared with controls. Morphological studies can be useful to allow the characterization of histopathological patterns of colonic wall remodelling and inflammation underlying bowel motor dysfunctions associated with obesity.