Toll-Like Receptor 4 Modulates Small Intestine Neuromuscular Function through Nitrergic and Purinergic Pathways

Objective: Toll-like receptors (TLRs) play a pivotal role in the homeostatic microflora-host crosstalk. TLR4-mediated modulation of both motility and enteric neuronal survival has been reported mainly for colon with limited information on the role of TLR4 in tuning structural and functional integrity of enteric nervous system (ENS) and in controlling small bowel motility. Methods: Male TLR4 knockout (TLR4-/-, 9 \ub1 1 weeks old) and sex- and age-matched wild-type (WT) C57BL/6J mice were used for the experiments. Alterations in ENS morphology and neurochemical code were assessed by immunohistochemistry whereas neuromuscular function was evaluated by isometric mechanical activity of ileal preparations following receptor and non-receptor-mediated stimuli and by gastrointestinal transit. Results: The absence of TLR4 induced gliosis and reduced the total number of neurons, mainly nNOS+ neurons, in ileal myenteric plexus. Furthermore, a lower cholinergic excitatory response with an increased inhibitory neurotransmission was found together with a delayed gastrointestinal transit. These changes were dependent on increased ileal non-adrenergic non-cholinergic (NANC) relaxations mediated by a complex neuronal-glia signaling constituted by P2X7 and P2Y1 receptors, and NO produced by nNOS and iNOS. Conclusion: We provide novel evidence that TLR4 signaling is involved in the fine-tuning of P2 receptors controlling ileal contractility, ENS cell distribution, and inhibitory NANC neurotransmission via the combined action of NO and adenosine-5\u2032-triphosphate (ATP). For the first time, this study implicates TLR4 at regulating the crosstalk between glia and neurons in small intestine and helps to define its role in gastrointestinal motor abnormalities during dysbiosis

I.S.Mu.L.T. Achilles Tendon Ruptures Guidelines

This work provides easily accessible guidelines for the diagnosis, treatment and rehabilitation of Achilles tendon ruptures. These guidelines could be considered as recommendations for good clinical practice developed through a process of systematic review of the literature and expert opinion, to improve the quality of care for the individual patient and rationalize the use of resources. This work is divided into two sessions: 1) questions about hot topics; 2) answers to the questions following Evidence Based Medicine principles. Despite the frequency of the pathology andthe high level of satisfaction achieved in treatment of Achilles tendon ruptures, a global consensus is lacking. In fact, there is not a uniform treatment and rehabilitation protocol used for Achilles tendon ruptures

Autoimmune Atrophic Gastritis: The Role of miRNA in Relation to Helicobacter Pylori Infection

IntroductionMicroRNAs (miRNAs) have been proposed as diagnostic markers, biomarkers of neoplastic progression, and possible therapeutic targets in several immune-mediated diseases. We aimed to analyze the expression profile of selected miRNAs (miR21, miR142, miR223, miR155) in patients with autoimmune atrophic gastritis (AAG), patients with non-autoimmune multifocal atrophic gastritis (MAG), and healthy control subjects (HC).Materials and methodsA total of 103 patients with AAG were consecutively recruited for this study among those attending our gastroenterology outpatient clinic. Participating patients were divided into two groups: primary, not Helicobacter pylori (HP)-associated related AAG (n=57, P-AAG) and HP-associated AAG (n=46, HP-AAG); this subgroup included HP-positive patients, patients with previously reported HP infection, and patients harboring antral atrophy, considered as a stigma of HP infection. We also included 20 sex-age-matched MAG patients and 10 HC. Upper endoscopy with gastric biopsies were performed on each AAG and MAG patient. Circulating levels of miR21-5p, miR142-3p, miR223-3p, and miR155-5p were measured by RT-PCR in all groups.ResultsMiR-21 was over-expressed in P-AAG (p=0.02), HP-AAG (p = 0.04), and MAG (p=0.03) compared with HC. By contrast, miR-142 was more expressed in HC than in HP-AAG (p=0.04) and MAG (p=0.03). MiR-155 showed no significant differences among the four subgroups, while, unexpectedly, miR-223 was overexpressed in HC compared to P-AAG (p=0.01), HP-AAG (p=0.003), and MAG (p<0.001), and was higher in P-AAG than in MAG (p=0.05).ConclusionsMiR-21 was over-expressed in patients with gastric precancerous conditions irrespective of etiology, while in the same subgroups miR-142 and miR-223 were under-expressed compared to healthy controls. Controlling miRNAs up- or downregulation could lead to a breakthrough in treating chronic autoimmune diseases and potentially interfere with the progression to cancer

Functional and Molecular Studies of the Crosstalk between Intestinal Microbioma and Enteric Nervous System and Potential Effects on the Gut-Brain Axis

L'interazione fra costituenti della parete intestinale e microflora commensale costituisce il principale artefice del mantenimento della barriera mucosale, della promozione dello sviluppo del tratto gastrointestinale (GI) e della modulazione delle funzioni GI. In questo contesto, giocano un ruolo chiave i recettori Toll-like (TLRs), un sistema di proteine che attivano la risposta immunitaria innata e assicurano l'integrità funzionale e strutturale del SNE. In questo studio sono state caratterizzate le alterazioni strutturali e funzionali del SNE murino indotte da: i) cambiamenti nel segnale dell’immunità innata, mediato dal recettore TLR4, ii) una miscela di fosfolipidi ossidati (OxPAPC), implicati nel blocco del segnale generato dai recettori TLR2 e TLR4 e iii) anomalie nella composizione del microbiota. Data l’importanza di un corretto segnale TLRs-dipendente nel mantenimento della rete nervosa e del codice neurochimico del SNE, segmenti di ileo provenienti da topi WT e TLR4-/- hanno evidenziato anomalie nell’attività contrattile neuromuscolare associate ad un’eccessiva modulazione inibitoria da NO ed ATP, a sostegno della presenza di un dialogo tra TLR4, SNE e microflora, fondamentale per la modulazione della funzione neuromuscolare. Studi strutturali su preparati di ileo di topi TLR4-/- evidenziano un’alterata architettura del SNE a livello gliale, indicando un coinvolgimento del recettore TLR4 nel mantenimento dell'integrità della rete gliale enterica mediato dalla produzione di ATP e della trasmissione purinergica evidenziano il ruolo di TLR4 nell’omeostasi strutturale e funzionale del SNE. Inoltre, è stato dimostrato che la mancanza del recettore TLR4 determina nell’ippocampo, come a livello del SNE, una compromessa neuroplasticità caratterizzata da alterazioni nella densità neuronale associata a variazioni della distribuzione della rete gliale, a confermare un ruolo fondamentale del segnale TLRs anche a livello centrale. In parallelo, è stato indagato il ruolo del segnale mediato dai TLRs nell’asse microbiota-TLRs-SNE, tramite la somministrazione in acuto con OxPAPC, inibitore del segnale mediato da entrambi i recettori TLR2 e TLR4, in topi adolescenti (3 ± 1 settimane). Il trattamento con OxPAPC ha causato un’alterazione significativa della risposta neuromuscolare associata a modifiche della rete neuro-gliale del SNE, confermando l’importanza del segnale mediato da tali recettori nell'assicurare l’integrità funzionale e strutturale del SNE durante l'adolescenza. Recenti studi riportano un ruolo primario nel dialogo tra i recettori TLRs e il sistema serotoninergico ed è stato evidenziato come OxPAPC comporti iperesponsività alla serotonina, alterazioni nella distribuzione recettoriale serotoninergica associata a variazioni nel metabolismo del triptofano, a sostegno della presenza di un dialogo tra immunità innata e sistema serotoninergico. Al fine di approfondire il ruolo dell'asse microbiota-intestino nell’omeostasi del SNE è stato messo a punto un modello animale di deplezione di microbiota intestinale attraverso la somministrazione di 4 antibiotici a topi adolescenti. Tale trattamento ha determinato un fenotipo simil germ-free ed alterazioni della motilità intestinale e dell'integrità della rete neuronale e gliale enterica. Data l’importanza di una corretta composizione del microbiota commensale nel mantenimento del codice neurochimico del SNE che nella produzione di neurotrasmettitori a livello enterico, sono state studiate le vie di neurotrasmissione coinvolte nella sensibilità viscerale. Un’alterata composizione del microbiota intestinale altera la sensibilità viscerale associata anomalie nella risposta neuromuscolare alla serotonina accompagnate da una compromessa rete recettoriale serotoninergica e del metabolismo del triptofano, sottolineando l’importanza di una corretta composizione del microbiota nel mantenimento delle funzioni mediate dal sistema serotoninergico

Lipid-based DNA/siRNA transfection agents disrupt neuronal bioenergetics and mitophagy

A multitude of natural and artificial compounds have been recognized to modulate autophagy, providing direct or, through associated pathways, indirect entry points to activation and inhibition. While these pharmacological tools are extremely useful in the study of autophagy, their abundance also suggests the potential presence of unidentified autophagic modulators that may interfere with experimental designs if applied unknowingly. Here, we report unanticipated effects on autophagy and bioenergetics in neuronal progenitor cells (NPCs) incubated with the widely used lipid-based transfection reagent lipofectamine (LF), which induced mitochondria depolarization followed by disruption of electron transport. When NPCs were exposed to LF for 5 h followed by 24, 48, and 72 h in LF-free media, an immediate increase in mitochondrial ROS production and nitrotyrosine formation was observed. These events were accompanied by disrupted mitophagy (accumulation of dysfunctional and damaged mitochondria, and of LC3II and p62), in an mTOR- and AMPK-independent manner, and despite the increased mitochondrial PINK1 (PTEN-inducible kinase 1) localization. Evidence supported a role for a p53-mediated abrogation of parkin translocation and/or abrogation of membrane fusion between autophagosome and lysosomes. While most of the outcomes were LF-specific, only two were shared by OptiMEM exposure (with no serum and reduced glucose levels) albeit at lower extents. Taken together, our findings show that the use of transfection reagents requires critical evaluation with respect to consequences for overall cellular health, particularly in experiments designed to address autophagy-inducing effects and/or energy stress

The cellular amount of the common γ-chain influences spontaneous or induced cell proliferation

Mutations of the IL2RG encoding the common γ-chain (γc) lead to the X-linked SCID disease. Gene correction through ex vivo retroviral transduction restored the immunological impairment in the most of treated patients, although lymphoproliferative events occurred in five of them. Even though in two cases it was clearly documented an insertional mutagenesis in LMO2, it is conceivable that γc could have a role per se in malignant lymphoproliferation. The γc is a shared cytokine receptor subunit, involved also in growth hormone (GH) receptor signaling. Through short interfering RNA or using X-linked SCID B lympho-blastoid cell lines lacking γc, we demonstrate that self-sufficient growth was strongly dependent on γc expression. Furthermore, a correlation between γc amount and the extent of constitutive activation of JAK3 was found. The reduction of γc protein expression also reduced GH-induced proliferation and STAT5 nuclear translocation in B lymphoblastoid cell lines. Hence, our data demonstrate that γc plays a remarkable role in either spontaneous or GH-induced cell cycle progression depending on the amount of protein expression, suggesting a potential role as enhancing cofactor in lymphoproliferation. Copyright © 2009 by The American Association of Immunologists, Inc

Assessment of Nutritional Status by Bioelectrical Impedance in Adult Patients with Celiac Disease: A Prospective Single-Center Study

The gluten-free diet [GFD] has been linked to an increased risk of weight gain and the development of metabolic disorders. Most of the studies have focused on the effect of GFD on the Body Mass Index [BMI]. We aimed to evaluate the nutritional status using specific nutritional parameters in patients with celiac disease [CeD] at diagnosis and on a GFD compared to healthy controls. We recruited subjects at our outpatient clinic at the University of Padua. We collected demographic and clinical data and values obtained with bioelectrical impedance analysis. A total of 24 CeD patients and 28 healthy controls were enrolled. CeD patients at diagnosis had a lower body cell mass index [BCMI, p = 0.006], fat-free mass index [FFMI, p = 0.02], appendicular skeletal muscle index [ASMI, p = 0.02], and phase angle [PA] [p p p = ns]. CeD patients at diagnosis were found to have a poorer nutritional status than healthy controls, with a positive effect of the GFD on their nutritional status, underlining the inefficacy of evaluating this aspect through only BMI evaluation