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.

Bigger babies: what happens in real practice in a non-academic UK center? Detection accuracy and outcomes with induction.

BACKGROUND: There is emerging evidence of improved outcomes with induction of labour for pregnancies in which the baby is thought to be large. This trial identifies scan accuracy and the effect of intervention for pregnancies complicated by suspected large for gestational age (LGA) on customized chart outside an academic center. METHODS: This is a retrospective cohort study of 3 groups of induced pregnancies; women with a suspected LGA fetus, women with diabetes (DM) and a control group (C) of women that underwent induction of labour on or after 280 days gestation. Data collection and analysis were prespecified. Scan accuracy and outcomes between the cohorts were compared. RESULTS: Over 1 year there were 845 cases: LGA (128), DM (116) and control cases (601). Mean birthweights differed significantly. PPV of EFW for birthweight >90th centile on GROW chart, WHO chart, and >4 kg was 0.35-0.40. Projected birthweight of >4 kg significantly better predicted itself (AUROC 0.70, 0.74 and 0.80). Mean scan error was -5.2% and +15.6% for DM and LGA. Shoulder dystocia and neonatal morbidity were not increased in LGA despite the significant increase in AVD 28/128, 21.9% vs. 99/601, 16.5%, aOR 2.20 (1.07-4.5). SVD was significantly less likely LGA vs. C at 69/128, 53.9% vs. 413/601, 68.7% aOR 0.38 (95% CI: 0.21-0.70). CONCLUSIONS: Third trimester EFW for bigger babies was poorly predictive of macrosomia. Fetal outcomes were good but women selected and induced as LGA had higher rates of hemorrhage and intervention.

Sensitization of colonic nociceptors by IL-13 is dependent on JAK and p38 MAPK activity.

The effective management of visceral pain is a significant unmet clinical need for those affected by gastrointestinal diseases, such as inflammatory bowel disease (IBD). The rational design of novel analgesics requires a greater understanding of the mediators and mechanisms underpinning visceral pain. Interleukin-13 (IL-13) production by immune cells residing in the gut is elevated in IBD, and IL-13 appears to be important in the development of experimental colitis. Furthermore, receptors for IL-13 are expressed by neurons innervating the colon, though it is not known whether IL-13 plays any role in visceral nociception per se. To resolve this, we used Ca2+ imaging of cultured sensory neurons and ex vivo electrophysiological recording from the lumbar splanchnic nerve innervating the distal colon. Ca2+ imaging revealed the stimulation of small-diameter, capsaicin-sensitive sensory neurons by IL-13, indicating that IL-13 likely stimulates nociceptors. IL-13-evoked Ca2+ signals were attenuated by inhibition of Janus (JAK) and p38 kinases. In the lumbar splanchnic nerve, IL-13 did not elevate baseline firing, nor sensitize the response to capsaicin application, but did enhance the response to distention of the colon. In line with Ca2+ imaging experiments, IL-13-mediated sensitization of the afferent response to colon distention was blocked by inhibition of either JAK or p38 kinase signaling. Together, these data highlight a potential role for IL-13 in visceral nociception and implicate JAK and p38 kinases in pronociceptive signaling downstream of IL-13.

Sensitization of colonic nociceptors by TNFα is dependent on TNFR1 expression and p38 MAPK activity.

Visceral pain is a leading cause of morbidity in gastrointestinal diseases, which is exacerbated by the gut-related side-effects of many analgesics. New treatments are needed and further understanding of the mediators and mechanisms underpinning visceral nociception in disease states is required to facilitate this. The pro-inflammatory cytokine TNFα is linked to pain in both patients with inflammatory bowel disease and irritable bowel syndrome, and has been shown to sensitize colonic sensory neurons. Somatic, TNFα-triggered thermal and mechanical hypersensitivity is mediated by TRPV1 signalling and p38 MAPK activity respectively, downstream of TNFR1 receptor activation. We therefore hypothesized that TNFR1-evoked p38 MAPK activity may also be responsible for TNFα sensitization of colonic afferent responses to the TRPV1 agonist capsaicin, and noxious distension of the bowel. Using Ca2+ imaging of dorsal root ganglion sensory neurons, we observed TNFα-mediated increases in intracellular [Ca2+ ] and sensitization of capsaicin responses. The sensitizing effects of TNFα were dependent on TNFR1 expression and attenuated by p38 MAPK inhibition. Consistent with these findings, ex vivo colonic afferent fibre recordings demonstrated an enhanced response to noxious ramp distention of the bowel and bath application of capsaicin following TNFα pre-treatment. Responses were reversed by p38 MAPK inhibition and absent in tissue from TNFR1 knockout mice. Our findings demonstrate a contribution of TNFR1, p38 MAPK and TRPV1 to TNFα-induced sensitization of colonic afferents, highlighting the potential utility of these drug targets for the treatment of visceral pain in gastrointestinal disease. KEY POINTS: The pro-inflammatory cytokine TNFα is elevated in gastrointestinal disease and sensitizes colonic afferents via modulation of TRPA1 and NaV 1.8 activity. We further develop this understanding by demonstrating a role for p38 MAPK and TRPV1 in TNFα-mediated colonic afferent sensitization. Specifically, we show that: TNFα sensitizes sensory neurons and colonic afferents to the TRPV1 agonist capsaicin. TNFα-mediated sensitization of sensory neurons and colonic nociceptors is dependent on TNFR1 expression. TNFα sensitization of sensory neurons and colonic afferents to capsaicin and noxious ramp distension is abolished by inhibition of p38 MAPK. Collectively these data support the utility of targeting TNFα, TNFR1 and their downstream signalling via p38 MAPK for the treatment of visceral pain in gastrointestinal disease.

Microfluidic-assisted nanoprecipitation of (PEGylated) poly (d,l-lactic acid-co-caprolactone): Effect of macromolecular and microfluidic parameters on particle size and paclitaxel encapsulation.

In this work we evaluate the effect of polymer composition and architecture of (PEGylated) polyesters on particle size and paclitaxel (PTX) loading for particles manufactured via microfluidic-assisted, continuous-flow nanoprecipitation using two microfluidic chips with different geometries and mixing principles. We have prepared poly (d,l-lactic acid-co-caprolactone) (PLCL) from ring-opening polymerization (ROP) of LA and CL mixtures and different (macro) initiators (namely, 1-dodecanol, a MeO-PEG-OH, and a 4-armed star PEG-OH), rendering polyesters that vary in monomer composition (i.e. LA/CL ratios) and architecture (i.e. linear vs 4-armed star). Continuous-flow nanoprecipitation was assayed using two microfluidic chips: a cross-flow chip with a X-shaped mixing junction (2D laminar flow focusing) and a micromixer featuring a Y-shaped mixing junction and a split and recombine path (2D laminar flow focusing convinced with stream lamination for faster mixing). Nanoparticle formulations were produced with Z-average sizes in the range of 30-160 nm, although size selectivity could be seen for different polymer/chip combinations; for instance, smaller particles were obtained with Y-shaped micromixer (30-120 nm), specially for the PEGylated polyesters (30-50 nm), whereas the cross-flow chip systematically produced larger particles (80-160 nm). Loading of the anti-cancer drug paclitaxel (PTX) was also heavily influenced not only by the nature of the polyester, but also by the geometry of the microfluidic chip; higher drug loadings were obtained with the cross-flow reactor and the star block copolymers. Finally, decreasing the LA/CL ratio generally had a positive effect on drug loading.