SummaryNaV1.9 regulates normal colonic afferent mechanosensation and is required for hypersensitivity to noxious inflammatory mediators and those derived from inflammatory bowel disease tissues.

This first-in-human study demonstrates afferent nerve recordings from human gut tissue ex vivo and shows that tissue may be stimulated both chemically and mechanically to study neuronal responses. Collectively, the results provide preliminary evidence to validate this in vitro human tissue model as one that may aid future disease mechanistic studies and candidate drug testing.

Background The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions. Methods This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated ‘standard’ or ‘COVID-altered’, in the preoperative, operative and post-operative setting. Findings Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had ‘COVID-altered’ management. ‘Bridging’ endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2–9%) using ‘NHS Predict’. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey. Conclusions The majority of ‘COVID-altered’ management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown.

ObjectiveThe development of effective visceral analgesics free of deleterious gut-specific side effects is a priority. We aimed to develop a reproducible methodology to study visceral nociception in human tissue that could aid future target identification and drug evaluation.DesignElectrophysiological (single unit) responses of visceral afferents to mechanical (von Frey hair (VFH) and stretch) and chemical (bradykinin and ATP) stimuli were examined. Thus, serosal afferents (putative nociceptors) were used to investigate the effect of tegaserod, and transient receptor potential channel, vanilloid 4 (TRPV4) modulation on mechanical responses.ResultsTwo distinct afferent fibre populations, serosal (n=23) and muscular (n=21), were distinguished based on their differences in sensitivity to VFH probing and tissue stretch. Serosal units displayed sensitivity to key algesic mediators, bradykinin (6/14 units tested) and ATP (4/10), consistent with a role as polymodal nociceptors, while muscular afferents are largely insensitive to bradykinin (0/11) and ATP (1/10). Serosal nociceptor mechanosensitivity was attenuated by tegaserod (−20.8±6.9%, n=6, p<0.05), a treatment for IBS, or application of HC067047 (−34.9±10.0%, n=7, p<0.05), a TRPV4 antagonist, highlighting the utility of the preparation to examine the mechanistic action of existing drugs or novel analgesics. Repeated application of bradykinin or ATP produced consistent afferent responses following desensitisation to the first application, demonstrating their utility as test stimuli to evaluate analgesic activity.ConclusionsFunctionally distinct subpopulations of human visceral afferents can be demonstrated and could provide a platform technology to further study nociception in human tissue.

Activation of visceral nociceptors by inflammatory mediators contributes to visceral hypersensitivity and abdominal pain associated with many gastrointestinal disorders. Purine and pyrimidine nucleotides (e.g., ATP and UTP) are strongly implicated in this process following their release from epithelial cells during mechanical stimulation of the gut, and from immune cells during inflammation. Actions of ATP are mediated through both ionotropic P2X receptors and metabotropic P2Y receptors. P2X receptor activation causes excitation of visceral afferents; however, the impact of P2Y receptor activation on visceral afferents innervating the gut is unclear. Here we investigate the effects of stimulating P2Y receptors in isolated mouse colonic sensory neurons, and visceral nociceptor fibers in mouse and human nerve-gut preparations. Additionally, we investigate the role of Na v 1.9 in mediating murine responses. The application of UTP (P2Y 2 and P2Y 4 agonist) sensitized colonic sensory neurons by increasing action potential firing to current injection and depolarizing the membrane potential. The application of ADP (P2Y 1 , P2Y 12 , and P2Y 13 agonist) also increased action potential firing, an effect blocked by the selective P2Y 1 receptor antagonist MRS2500. UTP or ADP stimulated afferents, including mouse and human visceral nociceptors, in nerve-gut preparations. P2Y 1 and P2Y 2 transcripts were detected in 80% and 56% of retrogradely labeled colonic neurons, respectively. Na v 1.9 transcripts colocalized in 86% of P2Y 1 -positive and 100% of P2Y 2 -positive colonic neurons, consistent with reduced afferent fiber responses to UTP and ADP in Na v 1.9 Ϫ/Ϫ mice. These data demonstrate that P2Y receptor activation stimulates mouse and human visceral nociceptors, highlighting P2Y-dependent mechanisms in the generation of visceral pain during gastrointestinal disease.

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BACKGROUND AND PURPOSECholinesterase inhibitors such as neostigmine are used for acute colonic pseudo-obstruction, but cardio-bronchial side-effects limit use. To minimize side-effects, lower doses could be combined with a 5-HT4 receptor agonist, which also facilitates intestinal cholinergic activity. However, safety concerns, especially in the elderly, require drugs with good selectivity of action. These include the AChE inhibitor donepezil (used for Alzheimer's disease, with reduced cardio-bronchial liability) and prucalopride, the first selective, clinically available 5-HT4 receptor agonist. This study examined their individual and potential synergistic activities in human colon. EXPERIMENTAL APPROACHNeuronally mediated muscle contractions and relaxations of human colon were evoked by electrical field stimulation (EFS) and defined phenotypically as cholinergic, nitrergic or tachykinergic using pharmacological tools; the effects of drugs were determined as changes in 'area under the curve'. KEY RESULTSPrucalopride increased cholinergically mediated contractions (EC50 855 nM; 33% maximum increase), consistent with its ability to stimulate intestinal motility; donepezil (477%) and neostigmine (2326%) had greater efficacy. Concentrations of donepezil (30-100 nM) found in venous plasma after therapeutic doses had minimal ability to enhance cholinergic activity. However, donepezil (30 nM) together with prucalopride (3, 10 μM) markedly increased EFS-evoked contractions compared with prucalopride alone (P = 0.04). For example, the increases observed with donepezil and prucalopride 10 μM together or alone were, respectively, 105 ± 35%, 4 ± 6% and 35 ± 21% (n = 3-7, each concentration). CONCLUSIONS AND IMPLICATIONSPotential synergy between prucalopride and donepezil activity calls for exploration of this combination as a safer, more effective treatment of colonic pseudo-obstruction. AbbreviationsAUC, area under the curve; Cmax, peak concentration of drug measured in blood after a single dose; EFS, electrical field stimulation; Emax, maximum response to agonist; GI, gastrointestinal; L-NAME, Nω-nitro-L-arginine methyl ester; NK, neurokinin; TTX, tetrodotoxin BJP IntroductionRestoration of normal intestinal motility is a key objective in treatment of a range of acute and chronic digestive motility disorders. In the most common -chronic constipation, laxatives remain the mainstay of pharmacological intervention, although new drugs have recently been introduced. These include prucalopride, a selective 5-HT4 receptor agonist, which facilitates enteric cholinergic and nitrergic activities to promote intestinal motility (Cellek et al., 2006), and lubiprostone and linaclotide, which, respectively, activate chloride type-2 channels and guanylate cyclase type-C receptors to promote defecation primarily by increasing fluid secretion into the lumen (Lembo et al., 2011;Chey et al., 2012). Such breakthroughs have renewed interest in how best to treat other conditions associated with hypomotility and also with acute or chronic small...

Background: Single-use negative pressure wound therapy (NPWT) has been shown to encourage wound healing. It is often used when patient factors impair wound healing, or in more complex wounds, such as in implant-based breast reconstruction. We report the findings of a prospective cohort study comparing the use of NPWT with standard dressings in prepectoral breast reconstruction. Methods: A prospective database of implant-based reconstruction from a single institution was mined to identify patients who underwent prepectoral reconstruction. Patient demographics, operative data, surgical complications, and 90-day outcomes were compared between patients who had NPWT and those who had standard dressings. Results: Prepectoral implant-based breast reconstruction was performed on 307 breasts. NPWT dressings were used in 126 cases, with standard dressings used in 181 cases. Wound breakdown occurred in 10 cases after standard dressings versus 1 where NPWT was utilized. Of the standard dressing cases, only 3 implants were salvaged, while 7 cases led to implant loss. The 1 case of wound breakdown in the NPWT cohort settled with conservative measures. The cost of a reconstructive failure was £14,902, and the use of NPWT resulted in a cost savings of £426 per patient. Conclusions: The utilization of single-use NPWT reduces the rate of wound breakdown and implant loss in prepectoral implant-based reconstruction. In addition to the significant clinical benefits, this approach is cost-saving compared with standard dressings. These data suggest that prepectoral implant reconstruction should be considered as an indication for the use of NPWT.