CD4+ROR γ t++ and Tregs in a Mouse Model of Diet-Induced Nonalcoholic Steatohepatitis.

BACKGROUND AND AIMS: Inflammatory mediators that cross-talk in different metabolically active organs are thought to play a crucial role in the pathogenesis of Nonalcoholic Steatohepatitis (NASH). This study was aimed at investigating the CD4+RORγt+ T-helper cells and their counterpart, the CD4+CD25+FOXP3+ regulatory T cells in the liver, subcutaneous adipose tissue (SAT), and abdominal adipose tissue (AAT) in a high fat diet (HFD) mouse model. METHODS: C57BL6 mice were fed a HFD or a normal diet (ND). Liver enzymes, metabolic parameters, and liver histology were assessed. The expression of CD4+RORγt+ cells and regulatory T cells in different organs (blood, liver, AAT, and SAT) were analyzed by flow cytometry. Cytokine and adipokine tissue expression were studied by RT-PCR. RESULTS: Mice fed a HFD developed NASH and metabolic alterations compared to normal diet. CD4+RORγt++ cells were significantly increased in the liver and the AAT while an increase of regulatory T cells was observed in the SAT of mice fed HFD compared to ND. Inflammatory cytokines were also upregulated. CONCLUSIONS: CD4+RORγt++ cells and regulatory T cells are altered in NASH with a site-specific pattern and correlate with the severity of the disease. These site-specific differences are associated with increased cytokine expression.

P2X3 receptors mediate visceral hypersensitivity during acute chemically-induced colitis and in the post-inflammatory phase via different mechanisms of sensitization.

OBJECTIVES: Experiments using P2X3 knock-out mice or more general P2X receptor antagonists suggest that P2X3 receptors contribute to visceral hypersensitivity. We aimed to investigate the effect of the selective P2X3 antagonist A-317491 on visceral sensitivity under physiological conditions, during acute colitis and in the post-inflammatory phase of colitis. METHODS: Trinitrobenzene sulphonic-acid colitis was monitored by colonoscopy: on day 3 to confirm the presence of colitis and then every 4 days, starting from day 10, to monitor convalescence and determine the exact timepoint of endoscopic healing in each rat. Visceral sensitivity was assessed by quantifying visceromotor responses to colorectal distension in controls, rats with acute colitis and post-colitis rats. A-317491 was administered 30 min prior to visceral sensitivity testing. Expression of P2X3 receptors (RT-PCR and immunohistochemistry) and the intracellular signalling molecules cdk5, csk and CASK (RT-PCR) were quantified in colonic tissue and dorsal root ganglia. ATP release in response to colorectal distension was measured by luminiscence. RESULTS: Rats with acute TNBS-colitis displayed significant visceral hypersensitivity that was dose-dependently, but not fully, reversed by A-317491. Hypersenstivity was accompanied by an increased colonic release of ATP. Post-colitis rats also displayed visceral hypersensitivity that was dose-dependently reduced and fully normalized by A-317491 without increased release of ATP. A-317491 did not modify visceral sensitivity in controls. P2X3 mRNA and protein expression in the colon and dorsal root ganglia were similar in control, acute colitis and post-colitis groups, while colonic mRNA expression of cdk5, csk and CASK was increased in the post-colitis group only. CONCLUSIONS: These findings indicate that P2X3 receptors are not involved in sensory signaling under physiological conditions whereas they modulate visceral hypersensitivity during acute TNBS-colitis and even more so in the post-inflammatory phase, albeit via different mechanisms of sensitization, validating P2X3 receptors as potential new targets in the treatment of abdominal pain syndromes.

Exploring associations between lower urinary tract symptoms (LUTS) and gastrointestinal (GI) problems in women: a study in women with urological and GI problems vs a control population.

OBJECTIVES: To study the prevalence of self-reported lower urinary tract symptoms (LUTS) in women consulting a Gastroenterology clinic with complaints of functional constipation (FC), fecal incontinence (FI) or both, compared with a female control population. Also, to study the influence of FC, FI, or both on self-reported LUTS in women attending a Urology clinic. PATIENTS AND METHODS: We present a retrospective study of data collected through a validated self-administered bladder and bowel symptom questionnaire in a tertiary referral hospital from three different female populations: 104 controls, 159 gastroenterological patients and 410 urological patients. Based on the reported bowel symptoms, patients were classified as having FC, FI, a combination of both, or, no FC or FI. LUTS were compared between the control population and the gastroenterological patients, and between urological patients with and without concomitant gastroenterological complaints. Results were corrected for possible confounders through logistic regression analysis. RESULTS: The prevalence of LUTS in the control population was similar to large population-based studies. Nocturia was significantly more prevalent in gastroenterological patients with FI compared with the control population [odds ratio (OR) 9.1]. Female gastroenterological patients with FC more often reported straining to void (OR 10.3), intermittency (OR 5.5), need to immediately re-void (OR 3.7) and feeling of incomplete emptying (OR 10.5) compared with the control population. In urological patients, urgency (94%) and urgency urinary incontinence (UUI, 54% of UI) were reported more often by patients with FI than by patients without gastroenterological complaints (58% and 30% of UI respectively), whereas intermittency (OR 3.6), need to immediately re-void (OR 2.2) and feeling of incomplete emptying (OR 2.2) were reported more often by patients with FC than by patients without gastroenterological complaints. CONCLUSION: As LUTS are reported significantly more often by female gastroenterological patients than by a control population, and as there is a difference in self-reported LUTS between female urological patients with different concomitant gastroenterological complaints, we suggest that general practitioners, gastroenterologists and urologists should always include the assessment of symptoms of the other pelvic organ system in their patient evaluation. The clinical correlations between bowel symptoms and LUTS may be explained by underlying neurological mechanisms.

Treatment with egg antigens of Schistosoma mansoni ameliorates experimental colitis in mice through a colonic T-cell-dependent mechanism.

BACKGROUND: Helminth-derived molecules are being identified as a new therapeutic approach for immune-mediated diseases. We investigated the anti-inflammatory effect and the immunological mechanisms of Schistosoma mansoni soluble egg antigens (SmSEA) in a mouse model of chronic colitis. METHODS: Colitis was induced in immunocompromised severe combined immunodeficiency mice by the adoptive transfer of CD4CD25CD62L T cells. Two weeks post-transfer, SmSEA treatments were started (study 1: 1 × 20 µg SmSEA per week 5 times; study 2: 2 × 20 µg SmSEA per week 3 times). From the start of the treatment (week 2), the clinical outcome and colonic inflammation were assessed at different time points by a clinical disease score and colonoscopy, respectively. At the end of the studies, the colons were harvested for macroscopic examination, and colonic lamina propria mononuclear cells were isolated for flow cytometric T-cell characterization. RESULTS: In both studies, administration of SmSEA in colitis mice improved all the inflammatory parameters studied. However in study 1, this beneficial effect on inflammation diminished with time, and the T-cell characterization of the lamina propria mononuclear cells, performed at week 6, revealed no immunological effects of the SmSEA treatment. In study 2, mice were killed earlier (week 4) and at that time point, we found a significant downregulation of the number of interleukin-17A-producing T cells and a significant upregulation of the number of interleukin-4-producing T cells in the colon of the SmSEA-treated colitis mice. CONCLUSIONS: Our results demonstrated that the administration of SmSEA reduces the severity of colitis in the adoptive transfer mouse model characterized by an increased Th2 response and a suppressed Th17 response in the colon.

Worm proteins of Schistosoma mansoni reduce the severity of experimental chronic colitis in mice by suppressing colonic proinflammatory immune responses.

Although helminthic therapy as a possible new option to treat inflammatory bowel disease is a well-established concept by now, the search for immunomodulatory helminth-derived compounds and their mechanisms of action is still ongoing. We investigated the therapeutic potential and the underlying immunological mechanisms of Schistosoma mansoni soluble worm proteins (SmSWP) in an adoptive T cell transfer mouse model of chronic colitis. Both a curative and a preventive treatment protocol were included in this study. The curative administration of SmSWP (started when colitis was established), resulted in a significant improvement of the clinical disease score, colonoscopy, macroscopic and microscopic inflammation score, colon length and myeloperoxidase activity. The therapeutic potential of the preventive SmSWP treatment (started before colitis was established), was less pronounced compared with the curative SmSWP treatment but still resulted in an improved clinical disease score, body weight loss, colon length and microscopic inflammation score. Both the curative and preventive SmSWP treatment downregulated the mRNA expression of the proinflammatory cytokines IFN-γ and IL-17A and upregulated the mRNA expression of the anti-inflammatory cytokine IL-4 in the colon at the end of the experiment. This colonic immunomodulatory effect of SmSWP could not be confirmed at the protein level. Moreover, the effect of SmSWP appeared to be a local colonic phenomenon, since the flow cytometric T cell characterization of the mesenteric lymph nodes and the cytokine measurements in the serum did not reveal any effect of SmSWP treatment. In conclusion, SmSWP treatment reduced the severity of colitis in the adoptive transfer mouse model via the suppression of proinflammatory cytokines and the induction of an anti-inflammatory response in the colon.

The effect of chemically induced colitis, psychological stress and their combination on visceral pain in female Wistar rats.

Visceral sensitivity is of pathophysiological importance in abdominal pain disorders and can be modulated by inflammation and stress. However, it is unclear whether inflammation and stress alter visceral perception independently of each other or in conjunction through neuroendocrine interactions. Therefore, we compared the short- and long-term effects of experimental colitis and water avoidance stress (WAS), alone or in combination, on visceral sensitivity in female Wistar rats. Colitis was induced by trinitrobenzene sulfonic acid (TNBS) and colonoscopically confirmed. During WAS, rats were placed on a platform surrounded by water for 1 h. Visceral sensitivity was assessed by quantifying the visceromotor responses (VMRs) to colorectal distension. Activation of the hypothalamic-pituitary-adrenal axis was determined by measuring serum corticosterone in a separate protocol. TNBS instillation resulted in overt colitis, associated with significant visceral hypersensitivity during the acute inflammatory phase (3 days post-TNBS; n = 8/group); after colitis had subsided (28 days post-TNBS), hypersensitivity was resolved (n = 4-8/group). Single WAS was associated with increased VMRs of a magnitude comparable to acute TNBS-induced hypersensitivity (n = 8/group). However, after repetitive WAS no significant hypersensitivity was present (n = 8/group). No additive effect of colitis and stress was seen on visceral pain perception (n = 6-8/group). Corticosterone levels were only increased in acute TNBS-colitis, acute WAS and their combination. To conclude, both colitis and stress successfully induced short-term visceral hypersensitivity and activated the hypothalamic-pituitary-adrenal axis, but long-term effects were absent. In addition, our current findings do not support an additive effect of colitis and stress on visceral sensitivity in female Wistar rats.

Belgian consensus on chronic pancreatitis in adults and children: statements on diagnosis and nutritional, medical, and surgical treatment.

Chronic pancreatitis (CP) is an inflammatory disorder characterized by inflammation and fibrosis, resulting in a progressive and irreversible destruction of exocrine and endocrine pancreatic tissue. Clinicians should attempt to classify patients into one of the six etiologic groups according to the TIGARO classification system. MRI/MRCP, if possible with secretin enhancement, is considered the imaging modality of choice for the diagnosis of early-stage disease.In CP, pain is the most disabling symptom, with a significant impact on quality of life. Pain should be assessed using the Izbicki score and preferably treated using the "pain ladder" approach. In painful CP, endoscopic therapy (ET) can be considered as early as possible. This procedure can be combined with extracorporeal shock-wave lithotripsy (ESWL) in the presence of large (> 4 mm), obstructive stone(s) in the pancreatic head, and with ductal stenting in the presence of a single main pancreatic duct (MPD) stricture in the pancreatic head with a markedly dilated MPD. Pancreatic stenting should be pursued for at least 12 months in patients with persistent pain relief. On-demand stent exchange should be the preferred strategy. The simultaneous placement of multiple, side-by-side, pancreatic stents can be recommended in patients with MPD strictures persisting after 12 months of single plastic stenting. We recommend surgery in the following cases: a) technical failure of ET ; b) early (6 to 8 weeks) clinical failure ; c) definitive biliary drainage at a later time point; d) pancreatic ductal drainage when repetitive ET is considered unsuitable for young patients; e) resection of an inflammatory pancreatic head when pancreatic cancer cannot be ruled out; f) duodenal obstruction. Duodenopancreatectomy or oncological distal pancreatectomy should be considered for patients with suspected malignancy. Pediatricians should be aware of and systematically search for CP in the differential diagnosis of chronic abdominal pain. As malnutrition is highly prevalent in CP patients, patients at nutritional risk should be identified in order to allow for dietary counseling and nutritional intervention using oral supplements. Patients should follow a healthy balanced diet taken in small meals and snacks, with normal fat content. Enzyme replacement therapy is beneficial to symptomatic patients, but also in cases of subclinical insufficiency. Regular follow-up should be considered in CP patients, primarily to detect subclinical maldigestion and the development of pancreatogenic diabetes. Screening for pancreatic cancer is not recommended in CP patients, except in those with the hereditary form.

Of worms, mice and man: an overview of experimental and clinical helminth-based therapy for inflammatory bowel disease.

The incidence of inflammatory and autoimmune disorders is highest in well-developed countries which is directly related to their higher hygienic standards: it is suggested that the lack of exposure to helminths contributes to the susceptibility for immune-related diseases. Epidemiological, experimental and clinical data support the idea that helminths provide protection against immune-mediated diseases such as inflammatory bowel disease (IBD). The most likely mechanism for the suppression of immune responses by helminths is the release of helminth-derived immunomodulatory molecules. This article reviews the experimental and clinical studies investigating the therapeutic potential of helminth-based therapy in IBD and also focuses on the current knowledge of its immunomodulatory mechanisms of action highlighting innate as well as adaptive immune mechanisms. Identifying the mechanisms by which these helminths and helminth-derived molecules modulate the immune system will help in creating novel drugs for the treatment of IBD and other disorders that result from an overactive immune response.

Neuroanatomy of lower gastrointestinal pain disorders.

Chronic abdominal pain accompanying intestinal inflammation emerges from the hyperresponsiveness of neuronal, immune and endocrine signaling pathways within the intestines, the peripheral and the central nervous system. In this article we review how the sensory nerve information from the healthy and the hypersensitive bowel is encoded and conveyed to the brain. The gut milieu is continuously monitored by intrinsic enteric afferents, and an extrinsic nervous network comprising vagal, pelvic and splanchnic afferents. The extrinsic afferents convey gut stimuli to second order neurons within the superficial spinal cord layers. These neurons cross the white commissure and ascend in the anterolateral quadrant and in the ipsilateral dorsal column of the dorsal horn to higher brain centers, mostly subserving regulatory functions. Within the supraspinal regions and the brainstem, pathways descend to modulate the sensory input. Because of this multiple level control, only a small proportion of gut signals actually reaches the level of consciousness to induce sensation or pain. In inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) patients, however, long-term neuroplastic changes have occurred in the brain-gut axis which results in chronic abdominal pain. This sensitization may be driven on the one hand by peripheral mechanisms within the intestinal wall which encompasses an interplay between immunocytes, enterochromaffin cells, resident macrophages, neurons and smooth muscles. On the other hand, neuronal synaptic changes along with increased neurotransmitter release in the spinal cord and brain leads to a state of central wind-up. Also life factors such as but not limited to inflammation and stress contribute to hypersensitivity. All together, the degree to which each of these mechanisms contribute to hypersensitivity in IBD and IBS might be disease- and even patient-dependent. Mapping of sensitization throughout animal and human studies may significantly improve our understanding of sensitization in IBD and IBS. On the long run, this knowledge can be put forward in potential therapeutic targets for abdominal pain in these conditions.

Histamine H4 and H1 receptors contribute to postinflammatory visceral hypersensitivity.

OBJECTIVES: Substantial evidence implicates mast cells and their main constituent histamine in the pathogenesis of visceral hypersensitivity. We explored the specific contribution of histamine H4 (H4R) and H1 (H1R) receptors to visceral hypersensitivity in a postinflammatory rat model. DESIGN: Trinitrobenzenesulfonic acid (TNBS)-colitis was monitored individually by colonoscopy: first on day 3 to confirm the presence of colitis and then every 4 days, starting from day 10, to monitor convalescence and determine the exact timepoint of endoscopic healing in each rat. Experiments were performed 3 days after endoscopic resolution of colitis. Visceral sensitivity was assessed by quantifying visceromotor responses (VMRs) to colorectal distension. Colonic mast cell numbers, histamine release and H4R and H1R mRNA expression were quantified. JNJ7777120 (H4R antagonist) and/or levocetirizine (H1R antagonist) were administered 30 min prior to VMR assessment or histamine release assay. RESULTS: Postcolitis rats displayed a higher number of colonic mast cells, excessive histamine release and significantly enhanced VMRs. Heightened VMRs were dose-dependently reduced by JNJ7777120 and levocetirizine; combined administration of JNJ7777120 and levocetirizine potentiated the antinociceptive effect. In the colon, both H4R and H1R mRNA were present; in the dorsal root ganglia, only H1R mRNA was found. Only colonic H4R mRNA expression was increased in postcolitis rats. Excessive histamine release in postcolitis rats was attenuated by the highest dose of JNJ7777120. CONCLUSIONS: H4R and H1R antagonists dose-dependently reduce and even normalise postinflammatory visceral hypersensitivity via different underlying mechanisms but with a synergistic effect. Both receptor subtypes represent promising targets for the treatment of postinflammatory visceral hypersensitivity.

Renewed attention for overtube-assisted colonoscopy to prevent incomplete endoscopic examination of the colon.

BACKGROUND: Colonoscopy is the standard examination to detect mucosal pathology in the colon. However, failure to complete colonoscopy may reach more than 10% in population-based endoscopy practices. The reasons for incomplete conventional colonoscopy are diverse and result in missed diagnosis of colonic polyps and carcinoma. OBJECTIVE: Recent endoscopic developments have shown that the use of specialized overtubes may help to reach the cecum in the case of a difficult colonoscopy, even with less discomfort. Several types of overtubes are currently available, whereas other types are being developed and clinically evaluated. The current review highlights the development of overtubes for colonoscopy and the available clinical data on overtube-assisted colonoscopy in the case of incomplete conventional colonoscopy. DATA SOURCES: Data were derived from a PubMed search through November 2012. STUDY SELECTION: Available clinical literature data on recent developments in overtube-assisted colonoscopy were studied. INTERVENTION: A descriptive comparison was made of currently available endoscopy systems used for overtube-assisted colonoscopy. MAIN OUTCOME MEASURES: The primary outcomes measured were the feasibility and safety of different endoscopy systems to perform overtube-assisted colonoscopy. RESULTS: Several overtube-assisted colonoscopy systems have recently been developed to complete colonoscopy in the case of difficult conventional colonoscopy. Literature data show excellent feasibility to reach the cecum with very low complication rates and good patient tolerance for the different overtube systems. LIMITATIONS: The majority of available studies are uncontrolled case series describing 7 to 110 patients undergoing overtube-assisted colonoscopy with only 1 direct comparison between 2 overtube systems. CONCLUSIONS: Overtube-assisted colonoscopy has been shown to be useful in performing colonoscopy by increasing the cecal intubation rate and patient tolerance and by decreasing the need for sedation. There is no standardized superior overtube system at this moment.

Mechanisms of pelvic organ crosstalk: 1. Peripheral modulation of bladder inhibition by colorectal distention in rats.

PURPOSE: Bladder activity can be inhibited by afferent input from the colorectum (inhibitory rectovesical reflex). We evaluated the functional response of the rat bladder to nonnoxious and noxious colorectal distention, and investigated the mechanical and pharmacological peripheral modulation of this response. MATERIALS AND METHODS: In 70 female Sprague-Dawley® rats we evaluated the effect of nonnoxious (20 mm Hg) and noxious (40 and 60 mm Hg) colorectal distention on the micturition volume threshold and on bladder activity in a filled bladder. We also studied the effect of rectal balloon size (1.5 vs 3.5 cm long), and rectal administration of 2% lidocaine jelly or 1 mM allyl isothiocyanate solution on the inhibitory rectovesical reflex. RESULTS: Colorectal distention at 60 mm Hg increased the micturition volume threshold (mean ± SE 0.640 ± 0.056 vs 0.448 ± 0.035 ml in controls, p <0.001). Bladder contraction frequency was significantly decreased by 40 and 60 mm Hg colorectal distention vs controls (mean 0.62 ± 0.06 and 0.33 ± 0.05 per minute, respectively, vs 0.77 ± 0.03, each p <0.001). These effects were reversible and pressure dependent (p <0.001), and more pronounced using a large rectal balloon (mean 40 vs 60 mm Hg colorectal distention 0.35 ± 0.12 vs 0.07 ± 0.04 per minute, p = 0.004). We noted no significant graded inhibition of bladder contraction amplitude or duration. The inhibitory rectovesical reflex was reversibly abolished by intrarectal lidocaine administration. Intrarectal allyl isothiocyanate administration significantly increased the effect of noxious colorectal distention on bladder contraction frequency. CONCLUSIONS: Only noxious levels of colorectal distention initiated the inhibitory rectovesical reflex. The effect increased with rectal balloon size and with intrarectal administration of allyl isothiocyanate. It was reversibly abolished by lidocaine. Results suggest that spinal interneurons are the mechanism behind the inhibitory rectovesical reflex.

Infliximab induces remission in cryptogenic multifocal ulcerous stenosing enteritis: first case.

We present the case of a 29-year-old patient with a history of abdominal pain and vomiting. Based on wireless video capsule findings he was previously diagnosed with ileal Crohn's disease at a different institution, although the clinical and radiological picture was not typical and the response to corticosteroids was poor. We performed a single-balloon enteroscopy showing a short, ulcerous stenosis 50 cm proximal from Bauhin's valve. The endoscopic and clinical histopathological findings were compatible with cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). High dose corticosteroids were again started, without effect. The monoclonal tumor necrosis factor-α (TNF-α) antibody infliximab was added to the medical therapy. After induction therapy, both clinical and endoscopic amelioration was obtained. Larger case studies are needed to confirm the efficacy of TNF-α inhibition in steroid refractory CMUSE.

Colonoscopy and µPET/CT are valid techniques to monitor inflammation in the adoptive transfer colitis model in mice.

BACKGROUND: Preclinical in vivo research on inflammatory bowel diseases requires proper animal models and techniques allowing longitudinal monitoring of colonic inflammation without the need to kill animals. We evaluated colonoscopy and µ-positron emission tomography/computed tomography (µPET/CT) as monitoring tools in a model for chronic colitis in mice. METHODS: Colitis was induced by adoptive transfer of CD4(+)CD25(-)CD62L(+) T cells in immunocompromised severe combined immunodeficient mice. Three study protocols were designed. In study 1, colonoscopy and µPET/CT were performed once, 4 weeks after transfer. In study 2 and study 3, colitis was sequentially followed up through colonoscopy (study 2) or colonoscopy plus µPET/CT (study 3). Each study included postmortem evaluation of colonic inflammation (macroscopy, microscopy, and myeloperoxidase activity). RESULTS: In study 1, both colonoscopy and µPET/CT detected colitis 4 weeks after transfer. Study 2 showed a gradual increase in colonoscopic score from week 2 (1.4 ± 0.6) to week 8 (6.0 ± 1.1). In study 3, colitis was detected 2 weeks after transfer by µPET/CT (2.0 ± 0.4) but not by colonoscopy, whereas both techniques detected inflammation 4 and 6 weeks after transfer. Colonoscopy correlated with µPET/CT (r = 0.812, 0.884, and 0.781, respectively) and with postmortem analyses in all 3 studies. CONCLUSIONS: Adoptive transfer of CD4(+)CD25(-)CD62L(+) T cells in severe combined immunodeficient mice results in a moderate chronic colitis. Evolution of colitis could be monitored over time by both colonoscopy and µPET/CT. µPET/CT seems to detect inflammation at an earlier time point than colonoscopy. Both techniques represent reliable and safe methods without the need to kill animals.

Role of TRPV1 and TRPA1 in visceral hypersensitivity to colorectal distension during experimental colitis in rats.

The aim of the present study is to investigate the effects of TRPV1 and TRPA1 receptor antagonists and their synergism on the visceromotor responses during experimental colitis in rats. Colitis was induced in rats by a TNBS/ethanol enema at day 0 and was assessed at day 3 using endoscopy, histology and a myeloperoxidase assay. The visceromotor response to colorectal distension (10-80 mmHg) was evaluated in conscious rats before (control condition) and 3 days after 2,4,6-trinitrobenzene sulfonic acid (TNBS) administration (colitis condition). At day 3, visceromotor responses were assessed before and after treatment with a TRPV1 (BCTC) or TRPA1 (TCS-5861528) receptor antagonist either alone or in combination and either after intraperitoneal or intrathecal administration. Endoscopy, microscopy and myeloperoxidase activity indicated severe colonic tissue damage 3 days after TNBS administration. Colorectal distension-evoked visceromotor responses demonstrated a 2.9-fold increase during acute colitis (day 3) compared to control conditions. Intraperitoneal and intrathecal administration of BCTC or TCS-5861528 partially reversed the colitis-induced increase in visceromotor responses compared to control conditions (P<0.05). Intraperitoneal blockade of TRPA1 plus TRPV1 further decreased the enhanced visceromotor responses at high distension pressures (40-80 mmHg) compared to blockade of either TRPV1 or TRPA1 alone. This synergistic effect was not seen after combined intrathecal blockade of TRPA1 plus TRPV1. The present study demonstrates that in the rat, TRPV1 and TRPA1 play a pivotal role in visceral hypersensitivity at the peripheral and spinal cord level during acute TNBS colitis. Target interaction, however, is presumably mediated via a peripheral site of action.

Increased intrahepatic resistance in severe steatosis: endothelial dysfunction, vasoconstrictor overproduction and altered microvascular architecture.

Non-alcoholic fatty liver disease can progress to steatohepatitis and fibrosis, and is also associated with impaired liver regeneration. The pathophysiology remains elusive. We recently showed that severe steatosis is associated with an increase in portal pressure, suggesting liver flow impairment. The objective of this study is to directly assess total intrahepatic resistance and its potential functional and structural determinants in an in situ perfusion model. Male Wistar rats fed a control (n = 30) or a methionine-choline-deficient (MCD) diet (n = 30) for 4 weeks were compared. Liver tissue and serum analysis, in vivo haemodynamic measurements, in situ perfusion experiments and vascular corrosion casts were performed. The MCD group showed severe steatosis without inflammation or fibrosis on histology. Serum levels and liver tissue gene expression of interleukin (IL)-6, tumour necrosis factor-α, IL-1ß and interferon-γ, liver tissue myeloperoxidase activity and liver immunohistochemistry with anti-CD68 and anti-α smooth muscle actin were comparable between groups, excluding significant inflammation. Flow-pressure curves were significantly different between groups for all flows (slope values: 0.1636 ± 0.0605 mm Hg/ml/min in controls vs 0.7270 ± 0.0408 mm Hg/ml/min in MCD-fed rats, P < 0.001), indicating an increased intrahepatic resistance, which was haemodynamically significant (portocaval pressure gradient 2.2 ± 1.1 vs 8.2 ± 1.3 mm Hg in controls vs MCD, P<0.001). Dose-response curves to acetylcholine were significantly reduced in MCD-fed rats (P < 0.001) as was the responsiveness to methoxamine (P<0.001). Vascular corrosion casts showed a replacement of the regular sinusoidal anatomy by a disorganized pattern with multiple interconnections and vascular extensions. Liver phosphorylated endothelial NO synthase (eNOS)/eNOS and serum nitrite/nitrate were not increased in severe steatosis, whereas liver thromboxane synthase expression, liver endothelin-1 (ET-1) expression and serum andothelin-1 concentration were significantly increased. Severe steatosis induces a haemodynamically significant increase in intrahepatic resistance, which precedes inflammation and fibrogenesis. Both functional (endothelial dysfunction and increased thromboxane and ET-1 synthesis) and structural factors are involved. This phenomenon might significantly contribute to steatosis-related disease.

Noninvasive assessment of nonalcoholic fatty liver disease in obese or overweight patients.

BACKGROUND & AIMS: Reliable noninvasive tools are needed for staging nonalcoholic fatty liver disease (NAFLD). Published scoring systems have not been validated in prospective assessments of unselected patients. We aimed to identify factors that predicted development of nonalcoholic steatohepatitis (NASH) in a large group of overweight or obese patients and compared these with established factors. METHODS: We performed a prospective analysis of factors associated with the development and severity of NAFLD in patients at a single obesity center. We evaluated liver involvement in 542 patients by a large set of routine and non-routine parameters, including ultrasound and genetic testing. Those suspected of having NAFLD underwent liver biopsy (57.7%). Patients were divided into design cohort (n = 200) and validation cohort (n = 113) to identify factors associated with the presence and severity of NAFLD and NASH. RESULTS: Factors independently associated with development of NASH included increased levels of alanine aminotransferase (ALT), fasting levels of C-peptide, and ultrasound steatosis scores (USSs), with area under the receiver operating curve (AUROC) values of 0.854 in the design cohort and 0.823 in the validation cohort. NASH activity scores also correlated with level of ALT, USS, and fasting level of C-peptide (R(2) = 0.491). Independent predictors of advanced fibrosis included waist circumference and level of aspartate aminotransferase (AUROC values of 0.839 and 0.846 for design and validation cohorts, respectively; negative predictive values of 98% and 97%, respectively, for a cutoff of -2.14). Previously published scoring systems had significantly lower AUROC values. Levels of CK18 and PNPLA3 polymorphisms correlated with development of NASH but did not add value. CONCLUSIONS: Parameters routinely analyzed in assessing obese patients can be used to determine the presence of NASH and advanced fibrosis. Non-routine tests do not increase diagnostic accuracy. Previously published scores are significantly less accurate.