Transcriptomic profiling reveals a pronociceptive role for angiotensin II in inflammatory bowel disease.

ABSTRACT: Visceral pain is a leading cause of morbidity in inflammatory bowel disease (IBD), contributing significantly to reduced quality of life. Currently available analgesics often lack efficacy or have intolerable side effects, driving the need for a more complete understanding of the mechanisms causing pain. Whole transcriptome gene expression analysis was performed by bulk RNA sequencing of colonic biopsies from patients with ulcerative colitis (UC) and Crohn's disease (CD) reporting abdominal pain and compared with noninflamed control biopsies. Potential pronociceptive mediators were identified based on gene upregulation in IBD biopsy tissue and cognate receptor expression in murine colonic sensory neurons. Pronociceptive activity of identified mediators was assessed in assays of sensory neuron and colonic afferent activity. RNA sequencing analysis highlighted a 7.6-fold increase in the expression of angiotensinogen transcripts, Agt , which encode the precursor to angiotensin II (Ang II), in samples from UC patients ( P = 3.2 × 10 -8 ). Consistent with the marked expression of the angiotensin AT 1 receptor in colonic sensory neurons, Ang II elicited an increase in intracellular Ca 2+ in capsaicin-sensitive, voltage-gated sodium channel subtype Na V 1.8-positive sensory neurons. Ang II also evoked action potential discharge in high-threshold colonic nociceptors. These effects were inhibited by the AT 1 receptor antagonist valsartan. Findings from our study identify AT 1 receptor-mediated colonic nociceptor activation as a novel pathway of visceral nociception in patients with UC. This work highlights the potential utility of angiotensin receptor blockers, such as valsartan, as treatments for pain in IBD.

Incidence and Prevalence of Paediatric Inflammatory Bowel Disease Continues to Increase in the South of England.

OBJECTIVE: The incidence of paediatric inflammatory bowel disease (IBD) has been increasing over 25 years; however, contemporary trends are not established and the impact of COVID-19 on case rates is unclear. METHODS: Data from Southampton Children's hospital prospective IBD database were retrieved for 2002-2021. Incidence rates were calculated based on referral area populations and temporal trends analysed. Disease prevalence for those aged <18 years was calculated for 2017-2021. Monoclonal prescriptions were reported. RESULTS: In total, 1150 patients were included (mean age at diagnosis 12.63 years, 40.5% female). An estimated 704 patients had Crohn's disease (61.2%), 385 had ulcerative colitis (33.5%), and 61 had IBD unclassified (5.3%). Overall IBD incidence increased, ß = 0.843, P = 3 × 10 -6 , driven by Crohn's disease, ß = 0.732, P = 0.00024 and ulcerative colitis, ß = 0.816, P = 0.000011. There was no change in IBDU incidence, ß = 0.230, P = 0.33. From 2002-2021, 51 patients were diagnosed <6 years of age, 160 patients aged 6 to <10 years and 939 patients aged 10 to <18 years of age. Increased incidence was observed in patients aged 10 to <18 years of age (ß = 0.888, P = 1.8 × 10 -7 ). There was no significant change in incidence of IBD in <6 years (ß = 0.124, P = 0.57), or 6 to <10 years (ß = 0.146, P = 0.54). IBD prevalence increased by an average of 1.71%/year from 2017 to 2021, ß = 0.979, P = 0.004. The number of new monoclonal prescriptions increased from 6 in 2007 to 111 in 2021. CONCLUSIONS: IBD incidence continues to increase in Southern England. Compounding prevalence and increased monoclonal usage has implications for service provision.

Oral Iron Treatment Response and Predictors in Anaemic Adolescents and Adults with IBD: A Prospective Controlled Open-Label Trial.

BACKGROUND: Because of previous concerns about the efficacy and safety of oral iron for treating iron deficiency anaemia in inflammatory bowel disease [IBD], particularly in young people, we compared the effects of ferrous sulphate on haemoglobin response, disease activity and psychometric scores in adolescents and adults with IBD. We also assessed the relation of baseline serum hepcidin to haemoglobin response. METHODS: We undertook a prospective, open-label, 6-week non-inferiority trial of the effects of ferrous sulphate 200 mg twice daily on haemoglobin, iron status, hepcidin, disease activity (Harvey-Bradshaw Index, Simple Colitis Clinical Activity Index, C-reactive protein [CRP]), faecal calprotectin and psychometric scores in 45 adolescents [age 13-18 years] and 43 adults [>18 years]. RESULTS: On intention-to-treat analysis, ferrous sulphate produced similar rises in haemoglobin in adolescents {before treatment 10.3 g/dl [0.18] (mean [SEM]), after 11.7 [0.23]: p < 0.0001} and adults (10.9 g/dl [0.14], 11.9 [0.19]: p < 0.0001); transferrin saturation, ferritin [in adolescents] and hepcidin [in adults] also increased significantly. On per-protocol univariate analysis, the haemoglobin response was inversely related to baseline haemoglobin, CRP and hepcidin. Oral iron did not alter disease activity; it improved Short IBDQ and Perceived Stress Questionnaire scores in adults. CONCLUSION: Oral ferrous sulphate was no less effective or well-tolerated in adolescents than adults, and did not increase disease activity in this short-term study. The inverse relation between baseline CRP and hepcidin levels and the haemoglobin response suggests that CRP or hepcidin measurements could influence decisions on whether iron should be given orally or intravenously. [ClinTrials.gov registration number NCT01991314].

Item Generation and Reduction Toward Developing a Patient-reported Outcome for Pediatric Ulcerative Colitis (TUMMY-UC).

BACKGROUND: The Pediatric Ulcerative Colitis Activity Index (PUCAI) is a noninvasive clinician-based index, which reflects disease severity in pediatric ulcerative colitis (UC) when no endoscopy is performed. Here, we aimed to explore signs and symptoms important to children with UC and their caregivers as the first stage of developing a patient-reported outcome (PRO) measure for pediatric UC (ie, the TUMMY-UC index) to supplement endoscopic assessment. METHODS: Concept elicitation qualitative interviews were performed with children who have UC and their caregivers in 6 centers. Items were rank-ordered by the interviewees according to the frequency of endorsement and importance, graded on a 1 to 5 scale. RESULTS: A total of 46 children (ages 12.5 ±â€Š3.3 years, range 7-18, 48% boys, 83% with pancolitis, 24% with moderate-severe disease) and 33 caregivers were interviewed (ie, 79 interviews). The following items were identified by the children, in decreasing order of weights: abdominal pain (importance × frequency weight 3.9), rectal bleeding (3.6), stool frequency (3.0), stool consistency (3.0), general well-being/fatigue (2.9), urgency (1.9), and nocturnal stools (1.6). Two other items were scored lower: lack of appetite (1.1) and weight loss (0.6). Children 13 to 18 years comprehended adult vocabulary, children 8 to 12 years comprehended simple vocabulary, and younger children had poor understanding in completing the questions. CONCLUSIONS: In this first stage of the TUMMY-UC development, items were generated and ranked by input from patients. These items are now being explored for optimal vocabulary and response options. The TUMMY-UC will supplement the PUCAI in clinical trial outcome assessment.

Assessing the feasibility of injectable growth-promoting therapy in Crohn's disease.

BACKGROUND: Despite optimal therapy, many children with Crohn's disease (CD) experience growth retardation. The objectives of the study are to assess the feasibility of a randomised control trial (RCT) of injectable forms of growth-promoting therapy and to survey the attitudes of children with CD and their parents to it. METHODS: A feasibility study was carried out to determine study arms, sample size and numbers of eligible patients. A face-to-face questionnaire surveyed willingness to consent to future participation in the RCT. Eligibility to the survey was any child under 18 (with their parent/guardian) with CD whose height standard deviation score (HtSDS) was ≤+1. Of 118 questionnaires, 94 (80%) were returned (48 by children and 46 by parents). RESULTS: The median age of the patients in the survey was 14.3 years (range 7.0 to 17.7), and 35 (73%) were male. Their median HtSDS was -1.2 (-3.01, 0.23), and it was lower than the median mid-parental HtSDS of -0.6 (-3.1, 1.4). We analysed the willingness of the children whose HtSDS <-1 to take part in the proposed RCT, being those most likely to require treatment. Overall, 18 (47%) children and 17 (46%) parents were willing. This increased to 61% of children who were slightly concerned about their height and 100% (4/4) of those very concerned. A common reason for not taking part in the RCT was fear of injections (44%); 111 children are required for randomisation into three study arms from nine centres. CONCLUSIONS: Almost half of children and parents surveyed would take part in an RCT of growth-promoting therapy. Allaying fears about injections may result in higher recruitment rates.

CD4+ T cells are not essential for control of early acute Cryptosporidium parvum infection in neonatal mice.

Cryptosporidiosis is an important diarrheal disease of humans and neonatal livestock caused by Cryptosporidium spp. that infect epithelial cells. Recovery from Cryptosporidium parvum infection in adult hosts involves CD4(+) T cells with a strong Th1 component, but mechanisms of immunity in neonates are not well characterized. In the present investigation with newborn mice, similar acute patterns of infection were obtained in C57BL/6 wild-type (WT) and T and B cell-deficient Rag2(-/-) mice. In comparison with uninfected controls, the proportion of intestinal CD4(+) or CD8(+) T cells did not increase in infected WT mice during recovery from infection. Furthermore, infection in neonatal WT mice depleted of CD4(+) T cells was not exacerbated. Ten weeks after WT and Rag2(-/-) mice had been infected as neonates, no patent infections could be detected. Treatment at this stage with the immunosuppressive drug dexamethasone produced patent infections in Rag2(-/-) mice but not WT mice. Expression of inflammatory markers, including gamma interferon (IFN-γ) and interleukin-12p40 (IL-12p40), was higher in neonatal WT mice than in Rag2(-/-) mice around the peak of infection, but IL-10 expression was also higher in WT mice. These results suggest that although CD4(+) T cells may be important for elimination of C. parvum, these cells are dispensable for controlling the early acute phase of infection in neonates.

Cryptosporidium parvum infection rapidly induces a protective innate immune response involving type I interferon.

Type II interferon (IFN), IFN-gamma, is important in innate immunity to the intestinal protozoan parasite Cryptosporidium species, which infects epithelial cells (enterocytes). This investigation is, to our knowledge, the first to characterize the role of type I IFN in innate immunity to this parasite. Pretreatment of human or murine enterocyte cell lines with IFN-alpha/beta inhibited parasite development, and we identified that a key mechanism of cytokine action was to prevent parasite invasion of enterocytes. IFN-alpha/beta was rapidly expressed by infected murine enterocytes and also by bone marrow-derived dendritic cells that were exposed to live parasites. Treatment of neonatal severe combined immunodeficiency mice with anti-IFN-alpha/beta neutralizing antibodies before infection increased oocyst reproduction, as measured at the peak of infection, and parasite numbers in gut epithelium were also increased 2 days after infection. The latter observation correlated with strong intestinal expression of both IFN-alpha and IFN-beta messenger RNA within 24 h after infection. Treatment with anti-IFN-alpha/beta, however, did not reduce early expression of IFN-gamma. These findings identify a novel early innate host response against Cryptosporidium parvum involving IFN-alpha/beta.

Roles for NK cells and an NK cell-independent source of intestinal gamma interferon for innate immunity to Cryptosporidium parvum infection.

A gamma interferon (IFN-gamma)-dependent innate immune response operates against the intestinal parasite Cryptosporidium parvum in T- and B-cell-deficient SCID mice. Although NK cells are a major source of IFN-gamma in innate immunity, their protective role against C. parvum has been unclear. The role of NK cells in innate immunity was investigated using Rag2-/- mice, which lack T and B cells, and Rag2-/- gammac-/- mice, which, in addition, lack NK cells. Adult mice of both knockout lines developed progressive chronic infections; however, on most days the level of oocyst excretion was higher in Rag2-/- gammac-/- mice and these animals developed morbidity and died, whereas within the same period the Rag2-/- mice appeared healthy. Neonatal mice of both mouse lines survived a rapid onset of infection that reached a higher intensity in Rag2-/- gammac-/- mice. Significantly, similar levels of intestinal IFN-gamma mRNA were expressed in Rag2-/- and Rag2-/- gammac-/- mice. Also, infections in each mouse line were exacerbated by treatment with anti-IFN-gamma neutralizing antibodies. These results support a protective role for NK cells and IFN-gamma in innate immunity against C. parvum. In addition, the study implies that an intestinal cell type other than NK cells may be an important source of IFN-gamma during infection and that NK cells may have an IFN-gamma-independent protective role.