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Background The pentapeptide ghrelin agonist, relamorelin, accelerates colonic transit in patients with chronic constipation (CC). In a murine model, relamorelin decreased excitability of colonic circular smooth muscle cells and colonic intraluminal pressure. Aim To determine short-term effects of relamorelin on colonic motility measured by barostat and multilumen manometry in CC. Methods In a placebo-controlled, single-dose, double-blind, randomized study in patients with CC, we investigated the motor effects of relamorelin, 100 μg, SQ (12 patients) compared to placebo SQ (six patients). A motility-barostat balloon assembly was used to measure colonic compliance; tone and phasic pressure activity were measured before and after a 1000-kcal milkshake meal (administered ~60 min post-medication). Overall “background” phasic pressure activity was assessed by: average amplitude and motility index (MI = ln[sum amplitudes × #contractions + 1]) over defined periods. High-amplitude propagating contractions (HAPCs) were characterized by amplitude >75 mmHg and propagating contractions >50 mmHg; both were propagated over at least 10 cm. Postprandial HAPCs were the primary end point. The study sample had 80 % power to detect an increase of 3.3 HAPCs in the hour post-meal. Results Relamorelin, 100 μg, significantly induced more pre-meal propagated contractions [PCs of either >50 or >75 mmHg] compared to placebo ( p  < 0.05). Relamorelin also induced more post-meal PCs >50 or >75 mmHg than placebo. Relamorelin did not significantly alter colonic compliance, fasting or postprandial phasic pressure activity (20 min pre-meal fasting MI) or tone, and 60 min postprandial phasic pressure amplitude or MI, or tone. Conclusions Relamorelin stimulates propagated colonic contractions without alteration of background irregular contractions in CC. ClinicalTrial.Gov registration number: NCT 01781104.

Effective antiretroviral therapy (ART) dramatically reduces AIDS-related complications, yet the life expectancy of long-term ART-treated HIV-infected patients remains shortened compared to that of uninfected controls, due to increased risk of non-AIDS related morbidities. Many propose that these complications result from translocated microbial products from the gut that stimulate systemic inflammation--a consequence of increased intestinal paracellular permeability that persists in this population. Concurrent intestinal immunodeficiency and structural barrier deterioration are postulated to drive microbial translocation, and direct evidence of intestinal epithelial breakdown has been reported in untreated pathogenic SIV infection of rhesus macaques. To assess and characterize the extent of epithelial cell damage in virally-suppressed HIV-infected patients, we analyzed intestinal biopsy tissues for changes in the epithelium at the cellular and molecular level. The intestinal epithelium in the HIV gut is grossly intact, exhibiting no decreases in the relative abundance and packing of intestinal epithelial cells. We found no evidence for structural and subcellular localization changes in intestinal epithelial tight junctions (TJ), but observed significant decreases in the colonic, but not terminal ileal, transcript levels of TJ components in the HIV+ cohort. This result is confirmed by a reduction in TJ proteins in the descending colon of HIV+ patients. In the HIV+ cohort, colonic TJ transcript levels progressively decreased along the proximal-to-distal axis. In contrast, expression levels of the same TJ transcripts stayed unchanged, or progressively increased, from the proximal-to-distal gut in the healthy controls. Non-TJ intestinal epithelial cell-specific mRNAs reveal differing patterns of HIV-associated transcriptional alteration, arguing for an overall change in intestinal epithelial transcriptional regulation in the HIV colon. These findings suggest that persistent intestinal epithelial dysregulation involving a reduction in TJ expression is a mechanism driving increases in colonic permeability and microbial translocation in the ART-treated HIV-infected patient, and a possible immunopathogenic factor for non-AIDS related complications.

BACKGROUND: Neurons of the enteric nervous system are characterised by high neuronal plasticity, with their number likely to change in response to various endogenous and exogenous substances. MATERIALS AND METHODS: Fifteen sexually immature gilts divided into 3 groups were used: control — animals receiving empty gelatin capsules; G1 — animals receiving a low dose of glyphosate — 0.05 mg/kg bw/day; G2 — animals receiving a higher dose of glyphosate — 0.5 mg/kg/day in gelatin capsules orally for 28 days. Frozen sections were then subjected to the procedure of double immunofluorescent staining. RESULTS: With low-dose supplementation, no effect on the SP- and CART-positive neuron population was observed. However, a reduction in the number of VAChT-positive neurons in the internal submucosal plexus was described, while the number of CGRP-positive neurons increased in all enteric plexuses. In response to a high glyphosate dose, the quantitative variability of the neurons was significantly more pronounced than that for a low dose. There was an increase in the number of SP- and CGRP-positive neurons and a decrease in the number of VAChT-positive neurons in both the myenteric plexus and the submucosal plexuses. The response of CART-positive neurons was the weakest, as a high dose of glyphosate led to an increase in the number of neurons only in the myenteric plexus. CONCLUSIONS: The above data show that glyphosate is an exogenous substance that affects neuronal populations of the enteric nervous system, in this case, the descending colon.

The enteric nervous system (ENS) can undergo adaptive and reparative changes in response to physiological and pathological stimuli. These manifest primarily as alterations in the levels of active substances expressed by the enteric neuron. While it is known that mycotoxins can affect the function of the central and peripheral nervous systems, knowledge about their influence on the ENS is limited. Therefore, the aim of the present study was to investigate the influence of low doses of zearalenone (ZEN) and T-2 toxin on calcitonin gene related peptide-like immunoreactive (CGRP-LI) neurons in the ENS of the porcine descending colon using a double immunofluorescence technique. Both mycotoxins led to an increase in the percentage of CGRP-LI neurons in all types of enteric plexuses and changed the degree of co-localization of CGRP with other neuronal active substances, such as substance P, galanin, nitric oxide synthase, and cocaine- and amphetamine-regulated transcript peptide. The obtained results demonstrate that even low doses of ZEN and T-2 can affect living organisms and cause changes in the neurochemical profile of enteric neurons.

1. Mechanisms involved in Ca(2+) sensitization of contractile elements induced by the activation of muscarinic receptors in membrane-permeabilized preparations of the rat proximal and distal colon were studied. 2. In alpha-toxin-permeabilized preparations from the rat proximal and distal colon, Ca(2+) induced a rapid phasic and subsequent tonic component. After Ca(2+)-induced contraction reached a plateau, guanosine 5'-triphosphate (GTP) and carbachol (CCh) in the presence of GTP further contracted preparations of both the proximal and distal colon (Ca(2+) sensitization). Y-27632, a rho-kinase inhibitor, inhibited GTP plus CCh-induced Ca(2+) sensitization more significantly in the proximal colon than in the distal colon. 3. Y-27632 at 10 microm had no effect on Ca(2+)-induced contraction or slightly inhibited phorbol-12,13-dibutyrate-induced Ca(2+) sensitization in either proximal or distal colon. Chelerythrine, a protein kinase C inhibitor, inhibited GTP plus CCh-induced Ca(2+) sensitization in the distal colon, but not in the proximal colon. The component of Ca(2+) sensitization that persisted after the chelerythrine treatment was completely inhibited by Y-27632. 4. In beta-escin-permeabilized preparations of the proximal colon, C3 exoenzyme completely inhibited GTP plus CCh-induced Ca(2+) sensitization, but PKC(19-31) did not. In the distal colon, C3 exoenzyme abolished GTP-induced Ca(2+) sensitization. It inhibited CCh-induced sensitization by 50 % and the remaining component was inhibited by PKC(19-31). 5. These results suggest that both protein kinase C and rho pathways in parallel mediate the Ca(2+) sensitization coupled to activation of muscarinic receptors in the rat distal colon, whereas the rho pathway alone mediates this action in the proximal colon.

During shock, prognosis of a patient depends largely on intestinal barrier function. The potency of gut epithelium to represent an obstacle to toxins is determined by the blood supply. All established methods of mucosal function determination necessitate the functional involvement of bloodstream. Microdialysis allows monitoring of extracellular substances in the gut submucosa, but its potential use for gut barrier integrity assessment is unknown. Twelve rats underwent perfusion of the descending colon either with 20 % ethanol or control medium (vehicle). Both media contained equal amounts of a radioactive tracer substance ((51)Cr-EDTA). Mucosal permeability for (51)Cr-EDTA was assessed by microdialysate to luminal perfusate activity ratios. Sampling was performed using the colon submucosal microdialysis technique. The group subjected to ethanol treatment had profound macro- and microscopical alterations in perfused colonic segment associated with a significant increase in tracer permeability during ethanol exposure (2.354+/-0.298 % for ethanol as opposed to 0.209+/-0.102 % for control group, p 0.01), which remained elevated for 60 min after cessation of ethanol administration (3.352+/-0.188 % for ethanol compared to 0.140+/-0.0838 % for the control group, p 0.001). Submucosal microdialysis with radioactive tracer substance can be considered a feasible and advantageous alternative of gut barrier function estimation. Parallel monitoring of local tissue chemistry with this method remains a challenge in the future.

Anaplastic lymphoma kinase (ALK) inhibitor alectinib has demonstrated significant potential in treating non-small cell lung cancer (NSCLC); however, its adverse effects remain a notable challenge for healthcare professionals. This report examines the case of a 79-year-old female lung cancer patient who presented with persistent colic in the left abdomen 10 months after initiating alectinib treatment. Upon admission, abdominal computed tomography revealed mild thickening of the descending colon wall, accompanied by free gas and surrounding exudation, leading to a diagnosis of descending colon perforation. After excluding alternative causes of gastrointestinal perforation, the condition was attributed to a severe adverse reaction associated with alectinib. While alectinib has been reported to cause serious gastrointestinal perforations, the underlying mechanism remains unclear and warrants further clinical investigation. Clinicians should be vigilant in recognizing and promptly managing this potential complication during alectinib therapy.

We report a rare case of haemorrhagic colitis attributed to dasatinib therapy in a 47-year-old African-American woman who was diagnosed with extramedullary T-lymphoblastic transformation of chronic myeloid leukaemia. The patient received intensive chemotherapy and dasatinib 100 mg/day. After achieving complete cytogenetic and major molecular response after 9 months of therapy, she developed bloody diarrhoea and pancytopenia. Colonoscopy showed inflammation of the descending colon and histopathology revealed patchy increase in intraepithelial lymphocytes. Dasatinib was stopped with prompt resolution of diarrhoea. The current literature suggests that there is an association in a subset of patients on dasatinib between clonal T-cell lymphocytosis in the peripheral blood and developing colitis and pleural effusions. These patients had a good response to dasatinib as did our patient. Our patient illustrates a unique disease presentation along with a rare drug adverse event.