Evidence of diabetes-specific autoimmunity in obese subjects with normal glucose tolerance.

BACKGROUND: Recently, significant attention has been paid to the possible activation of an autoimmune response in the presence of obesity. The aim of this study was to evaluate and compare the frequencies of autoantibodies typical of autoimmune diabetes in obese patients with normal glucose tolerance (NGT), obese patients with type 2 diabetes (T2D) and controls. We also evaluated the presence of immunoreactivity to Hashimoto's thyroiditis and autoimmune gastritis. MATERIALS AND METHODS: Consecutive sera from obese patients, 444 with NGT, 322 with T2D, and 212 controls were analysed by radioimmunoassay or enzyme-linked immunosorbent assay for glutamic acid decarboxylase, protein tyrosine phosphatase islet antigen-2 (IA-2)IC and IA-2(256-760) , islet beta-cell zinc cation transporter (ZnT8), thyroid peroxidase, and anti-parietal cell autoantibodies. RESULTS: Altogether the presence of organ-specific autoantibodies was significantly more frequent in obese patients with NGT (128/444, 28.5%) and obese with T2D (79/322, 24.5%) than in controls (36/212, 17%; P = 0.002). Thyroid peroxidase immunoreactivity was prevalent in all groups of subjects investigated. The frequencies of diabetes-specific autoantibodies were slightly higher in obese patients with NGT (20/444, 4.5%) than in obese with T2D (12/322, 3.7%) and controls (4/212, 1.9%). The anti IA-2(256-760) was the most frequent islet autoantibody in obese subjects with NGT (14/20, 70%). CONCLUSIONS: We observed significant evidence of immunoreactivity specific to diabetes, thyroid, and gastric-parietal cells in obese patients with NGT. The relatively higher frequency of the diabetes-related IA-2(256-760) autoantibodies in obese patients with NGT may suggest that this autoantibody could be associated with obesity the presence of obesity itself.

Protective Role of Postbiotic Mediators Secreted by Lactobacillus rhamnosus GG Versus Lipopolysaccharide-induced Damage in Human Colonic Smooth Muscle Cells.

BACKGROUND: Some beneficial effects of probiotics may be due to secreted probiotic-derived factors, identified as "postbiotic" mediators. The aim of this study was to evaluate whether supernatants harvested from Lactobacillus rhamnosus GG (LGG) cultures (ATCC53103 strain) protect colonic human smooth muscle cells (HSMCs) from lipopolysaccharide (LPS)-induced myogenic damage. MATERIALS AND METHODS: LGG was grown in de Man, Rogosa, Share medium at 37°C and samples were collected in middle and late exponential, stationary, and overnight phases. Supernatants were recovered by centrifugation, filtered, and stored at -20°C. The primary HSMCs culture was exposed for 24 hours to purified LPS of a pathogen strain of Escherichia coli (O111:B4) (1 µg/mL) with and without supernatants. Postbiotic effects were evaluated on the basis of HSMCs morphofunctional alterations and interleukin-6 (IL-6) production. Data are expressed as mean±SE (P<0.05 significant). RESULTS: LPS induced persistent, significant, 20.5%±0.7% cell shortening and 34.5%±2.2% decrease in acetylcholine-induced contraction of human HSMCs. These morphofunctional alterations were paralleled to a 365.65%±203.13% increase in IL-6 production. All these effects were dose-dependently reduced by LGG supernatants. Supernatants of the middle exponential phase already partially restored LPS-induced cell shortening by 57.34%±12.7% and IL-6 increase by 145.8%±4.3% but had no effect on LPS-induced inhibition of contraction. Maximal protective effects were obtained with supernatants of the late stationary phase with LPS-induced cell shortening restored by 84.1%±4.7%, inhibition of contraction by 85.5%±6.4%, and IL-6 basal production by 92.7%±1.2%. CONCLUSIONS: LGG-derived products are able to protect human SMCs from LPS-induced myogenic damage. Novel insights have been provided for the possibility that LGG-derived products could reduce the risk of progression to postinfective motor disorders.

Postbiotic activities of lactobacilli-derived factors.

Probiotics are alive nonpathogenic microorganisms present in the gut microbiota that confer benefits to the host for his health. They act through molecular and cellular mechanisms that contrast pathogen bacteria adhesion, enhance innate immunity, decrease pathogen-induced inflammation, and promote intestinal epithelial cell survival, barrier function, and protective responses. Some of these beneficial effects result to be determined by secreted probiotic-derived factors that recently have been identified as "postbiotic" mediators. They have been reported for several probiotic strains but most available literature concerns Lactobacilli. In this review, we focus on the reported actions of several secretory products of different Lactobacillus species highlighting the available mechanistic data. The identification of soluble factors mediating the beneficial effects of probiotics may present an opportunity not only to understand their fine mechanisms of action, but also to develop effective pharmacological strategies that could integrate the action of treatments with live bacteria.

From diverticulosis to complicated diverticular disease: Progression of myogenic alterations and oxidative imbalance.

BACKGROUND: The natural history and pathophysiology of diverticular disease (DD) are still uncertain. An ex-vivo human complicated DD (cDD) model has recently shown a predominant transmural oxidative imbalance. The present study aims to evaluate whether the previously described alterations may precede the symptomatic form of the disease. METHODS: Colonic surgical samples obtained from patients with asymptomatic diverticulosis (DIV), complicated DD, and controls were systematically and detailed morphologically and molecularly analyzed. Therefore, histologic, histomorphometric, immunohistochemical evaluation, and gene and protein expression analysis were performed to characterize colonic muscle changes and evaluate chronic inflammation, oxidative imbalance, and hypoxia. Functional muscle activity was tested on strips and isolated cells in response to contractile and relaxant agents. KEY RESULTS: Compared with controls, DD showed a marketed increase in muscle layer thickness, smooth muscle cell syncytium disarray, and increased interstitial fibrosis; moreover, the observed features were more evident in the cDD group. These changes mainly affected longitudinal muscle and were associated with altered contraction-relaxation dynamics and fibrogenic switch of smooth muscle cells. Chronic lymphoplasmacytic inflammation was primarily evident in the mucosa and spared the muscle. A transmural increase in carbonylated and nitrated proteins, with loss of antioxidant molecules, characterized both stages of DD, suggesting early oxidative stress probably triggered by recurrent ischemic events, more pronounced in cDD, where HIF-1 was detected in both muscle and mucosa. CONCLUSION & INFERENCES: The different DD clinical scenarios are part of a progressive process, with oxidative imbalance representing a new target in the management of DD.

Diverticular Disease Worsening Is Associated with Increased Oxidative Stress and Gut Permeability: New Insights by Circulating Biomarkers.

Diverticular disease (DD) management is impaired by its pathogenesis, which is still not completely defined, with an unmet clinical need for improved therapies. Ex vivo DD human models demonstrated the presence of a transmural oxidative imbalance that supports an ischemic pathogenesis. This study aimed to assess, with the use of circulating biomarkers, insights into DD pathogenesis and possible therapeutic targets. Nox2-derived peptide, H2O2, antioxidant capacity, isoprostanes, thromboxanes, TNF-α, LPS and zonulin were evaluated by ELISA in healthy subjects (HS) and asymptomatic and symptomatic DD patients. Compared to HS, DD patients presented low antioxidant capacity and increase in sNox2-dp, H2O2 and isoprostanes paralleled to a TNFα increase, lower than that of oxidative markers. TxB2 production correlated to Nox2 and isoprostanes, suggesting platelet activation. An increase in zonulin and LPS highlighted the role of gut permeability and LPS translocation in DD pathogenesis. The increase of all the markers statistically correlated with DD severity. The present study confirmed the presence of a main oxidative imbalance in DD and provides evidence of platelet activation driven by LPS translocation. The use of circulating biomarkers could represent a new clinical tool for monitoring disease progression and validate therapeutic strategies never tested in DD as antioxidant supplementation.

Eosinophilic Esophagitis: Cytokines Expression and Fibrotic Markers in Comparison to Celiac Disease.

INTRODUCTION: Eosinophilic esophagitis (EoE) is now recognized as the main inflammatory condition that leads to fibrosis, unlike other chronic inflammatory gastrointestinal diseases, such as celiac disease. The aim of our study is to characterize the collagen deposition and cytokine expression involved in the fibrogenic response in patients affected by EoE in comparison to celiac disease. MATERIALS AND METHODS: Consecutive patients with a clinical suspicion of untreated EoE or active celiac disease were enrolled. In the control group, patients with negative upper endoscopy were included. Total RNA was isolated from biopsy specimens using a commercial kit (SV Total RNA Isolation System, Promega Italia Srl). Quantitative real-time PCR (qRT-PCR) was performed in triplicate using a StepOne™ Real-Time PCR instrument (Thermo Fisher Scientific, Monza, Italy). mRNA encoding for inflammatory molecules: interleukin 4 (IL-4), interleukin 5 (IL-5), interleukin 13 (IL-13), and fibrotic markers: transforming growth factor beta 1 (TGF-ß), mitogen-activated protein kinase kinase kinase 7 (MAP3K7), serpin family E member 1 (SERPINE1), were quantified using TaqMan Gene Expression Assays (Applied Biosystems). RESULTS: In EoE, the qPCR analysis showed an increase in all the inflammatory cytokines. Both IL-5 and Il-3 mRNA expression resulted in a statistically significant increase in oesophageal mucosa with respect to the celiac duodenum, while no differences were present in IL-4 expression. TGF-ß expression was similar to the controls in the mid esophagus but reduced in the distal EoE esophagus (RQ: 0.46 ± 0.1). MAP3K7 expression was reduced in the mid esophagus (RQ: 0.59 ± 0.3) and increased in the distal esophagus (RQ: 1.75 ± 0.6). In turn, the expression of SERPINE1 was increased in both segments and was higher in the mid than in the distal esophagus (RQ: 5.25 ± 3.9, 1.92 ± 0.9, respectively). Collagen deposition was greater in the distal esophagus compared to the mid esophagus [18.1% ± 8 vs. 1.3% ± 1; p = 0.008]. CONCLUSIONS: The present study confirms the esophageal fibrotic involution involving the distal esophagus and shows that the inflammatory pathway in EoE is peculiar to this disease and different from other chronic inflammatory gastrointestinal disorders such as celiac disease.

Oxidative imbalance and muscular alterations in diverticular disease.

BACKGROUND: It is still a matter of debate if neuromuscular alterations reflect a primary event in diverticular disease (DD). AIMS: This study aimed to assess colonic wall layers from both stenotic and non-stenotic complicated DD, bio-phenotypic alterations, inflammatory and oxidative status. METHODS: A systematic analysis of colonic specimens obtained from stenotic and non-stenotic DD specimens was conducted and compared with controls. Biological activity and qPCR analysis were performed on longitudinal and circular muscles. Western blot analysis was performed throughout colonic wall layers to quantify oxidative and inflammatory markers. RESULTS: A homogenous increase in oxidative stress was observed through all the layers, which were more sharpened in the longitudinal muscle for a loss in antioxidant defenses. In both stenotic and non-stenotic colon, the longitudinal muscle presented an impaired relaxation and a cellular phenotypic switch driven by transforming growth factor-ß with an increase in mRNA expression of collagen Iα and a decrease in myosin heavy chain. The circular muscle, as the mucosa, was less affected by molecular alterations. No peculiar increase in inflammatory markers was observed. CONCLUSION: A longitudinal colonic myopathy is present in DD, independently from the disease stage associated with an oxidative imbalance that could suggest new therapeutic strategies.

The Impact of Oxidative Stress in Human Pathology: Focus on Gastrointestinal Disorders.

Accumulating evidence shows that oxidative stress plays an essential role in the pathogenesis and progression of many diseases. The imbalance between the production of reactive oxygen species (ROS) and the antioxidant systems has been extensively studied in pulmonary, neurodegenerative cardiovascular disorders; however, its contribution is still debated in gastrointestinal disorders. Evidence suggests that oxidative stress affects gastrointestinal motility in obesity, and post-infectious disorders by favoring the smooth muscle phenotypic switch toward a synthetic phenotype. The aim of this review is to gain insight into the role played by oxidative stress in gastrointestinal pathologies (GIT), and the involvement of ROS in the signaling underlying the muscular alterations of the gastrointestinal tract (GIT). In addition, potential therapeutic strategies based on the use of antioxidants for the treatment of inflammatory gastrointestinal diseases are reviewed and discussed. Although substantial progress has been made in identifying new techniques capable of assessing the presence of oxidative stress in humans, the biochemical-molecular mechanisms underlying GIT mucosal disorders are not yet well defined. Therefore, further studies are needed to clarify the mechanisms through which oxidative stress-related signaling can contribute to the alteration of the GIT mucosa in order to devise effective preventive and curative therapeutic strategies.

Recent advances in understanding and managing diverticulitis.

In the past few decades, the increasing socioeconomic burden of acute diverticulitis (AD) has become evident, and with the growth of the population age, this significant economic impact will likely continue to rise. Furthermore, recent evidence showed an increased rate of hospital admissions especially evident among women and younger individuals. The natural history and pathophysiology of this clinical condition is still to be fully defined, and efforts continue to be made in the identification of risk factors and the establishment of relative preventive strategies. The actual therapeutic strategies aimed to modulate gut microbiota, such as rifaximin or probiotics, or to reduce mucosal inflammation, such as mesalazine, present a relatively poor efficacy for both the prevention of the first AD episode (primary prevention) and its recurrence (secondary prevention). In the last few years, the main goal achieved has been in the management of AD in that uncomplicated AD can, to a larger extent, be managed in an outpatient setting with no or little supportive therapy, a strategy that will certainly impact on the health costs of this disease. The problem of AD recurrence remains a topic of debate. The aim of this review is to present updated evidence on AD epidemiology and relative open clinical questions and to analyze in detail predisposing and protective factors with an attempt to integrate their possible modes of action into the several pathogenic mechanisms that have been suggested to contribute to this multifactorial disease. A unifying hypothesis dealing with the colonic luminal and extra-luminal microenvironments separately is provided. Finally, evidence-based changes in therapeutic management will be summarized. Because of an ascertained multifactorial pathogenesis of uncomplicated and complicated AD, it is probable that a single 'causa prima' will not be identifiable, and a better stratification of patients could allow one to pursue tailored therapeutic algorithm strategies.

Myogenic oxidative imbalance interferes with antral motility in obese subjects.

BACKGROUND: Obesity is characterized by a systemic low-grade chronic inflammatory oxidative condition that affects vascular and cardiac smooth muscle relaxation. In human antrum, relaxation is mediated by vasoactive intestinal peptide (VIP) through cAMP and cGMP signaling pathways. A genome-wide association study has demonstrated an association between VIP and obesity. AIM: To evaluate smooth muscle activity in human obese antrum, both in in vitro preparations as well as in vivo. METHODS: Antral muscle strips and cells were isolated from surgical gastric samples from obese and normal weight subjects. Muscle contraction and relaxation, myogenic oxidative stress and inflammatory status were analyzed in vitro. Distal antral motility was evaluated in vivo by magnetic resonance imaging. RESULTS: Obese antral muscle cells showed an oxidative-inflammatory imbalance with overexpression of NLRP3 inflammasome, increased IL-1ß secretion and caspase1-activation, and reduced antioxidant capacity associated with a myogenic motor impairment of VIP-induced relaxation. The intracellular alterations were characterized by a decreased activation of the cAMP-signaling pathway and a decreased expression of eNOS. These in vitro alterations coincided with the hindering of antral motor activity observed in vivo. Apocynin treatment, counteracting oxidative stress, reverted alterations observed in obese antral muscle. CONCLUSION: Antral myogenic activity of obese subjects can be impaired by alterations of signaling pathways induced by oxidative stress.

Long-standing type 1 diabetes: patients with adult-onset develop celiac-specific immunoreactivity more frequently than patients with childhood-onset diabetes, in a disease duration-dependent manner.

To assess the frequency of celiac-associated humoral autoimmunity in patients with long-standing childhood- and adult-onset type 1 diabetes (LDM1) and whether it occurs more frequently as the disease progresses. IgA-/IgG-anti-tissue transglutaminase (IgA-tTG and IgG-tTG) and IgA-/IgG-deamidated gliadin (DGP) antibodies were analyzed in 277 LDM1 sera (120 females; disease duration 19.3 ± 12.3 years, range 5.0-54.0 years). Of the 277 patients, 147 were childhood-onset LDM1 ((CH)LDM1) and 130 adult-onset LDM1 ((AD)LDM1); 6.1 % LDM1 sera were tTG- and/or DGP-antibody-positive, with a lower frequency among (CH)LDM1 as compared with (AD)LDM1 patients (3.4 vs 9.2 %, p = 0.048). Celiac-associated immunoreactivity was significantly more frequent in LDM1 with >15 years of disease duration (9.4 vs 2.9 % in those with ≤15 years, p = 0.042) and among them in (AD)LDM1 (14.7 vs 4.2 % (CH)LDM1, p = 0.043). Celiac disease humoral immunoreactivity should be screened not only at diabetes onset, but also in long-standing patients, especially adults with disease duration >15 years.