Alcohol use disorders and liver fibrosis: an update.

Alcoholic liver disease (ALD) is currently, worldwide, the second most common cause of human fatalities every year. Alcohol use disorders (AUDs) lead to 80% of hepatotoxic deaths, and about 40% of cases of cirrhosis are alcohol-related. An acceptable daily intake (ADI) of ethanol is hard to establish and studies somewhat controversially recommend a variety of dosages of ADI, whilst others regard any intake as dangerous. Steatohepatitis should be viewed as "the rate limiting step": generally, it can be overcome by abstinence, although in some patients, abstinence has little effect, with the risk of fibrosis, leading in some cases to hepatocellular carcinoma (HCC). Chronic alcoholism can also cause hypercortisolism, specifically pseudo-Cushing Syndrome, whose diagnosis is challenging. If fibrosis is spotted early, patients may be enrolled in detoxification programs to achieve abstinence. Treatment drugs include silybin, metadoxine and adenosyl methionine. Nutrition and the proper use of micronutrients are important, albeit often overlooked in ALD treatment. Other drugs, with promising antifibrotic effects, are now being studied. This review deals with the clinical and pathogenetic aspects of alcohol-related liver fibrosis and suggests possible future strategies to prevent cirrhosis.

Sex- and Gender-Based Analysis on Norepinephrine Use in Septic Shock: Why Is It Still a Male World?

Sex and gender are fundamental health determinants and their role as modifiers of treatment response is increasingly recognized. Norepinephrine is a cornerstone of septic shock management and its use is based on the highest level of evidence compared to dopamine. The related 2021 Surviving Sepsis Campaign (SCC) recommendation is presumably applicable to both females and males; however, a sex- and gender-based analysis is lacking, thus not allowing generalizable conclusions. This paper was aimed at exploring whether sex- and gender-disaggregated data are available in the evidence supporting this recommendation. For all the studies underpinning it, four pairs of authors, including a woman and a man, extracted data concerning sex and gender, according to the Sex and Gender Equity in Research guidelines. Nine manuscripts were included with an overall population of 2126 patients, of which 43.2% were females. No sex analysis was performed and gender was never reported. In conclusion, the present manuscript highlighted that the clinical studies underlying the SCC recommendation of NE administration in septic shock have neglected the likely role of sex and gender as modifiers of treatment response, thus missing the opportunity of sex- and gender-specific guidelines.

Botulinum toxin injection for chronic anal fissure: a prospective controlled study with long follow-up.

BACKGROUND: Botulinum toxin is an effective therapeutic option for chronic anal fissure. However, there is no evidence about treatment standardization and long-term follow-up. We aimed to evaluate the short- and long-term efficacy and safety of botulinum toxin compared to close lateral internal sphincterotomy, with a 5-year follow-up. METHODS: This was a prospective, controlled, single-center study conducted at University Hospital of Ferrara, Ferrara, Italy. The primary outcome was fissure healing at 1 month. Secondary outcomes were Quality-of-Life (QoL) at 1 month and after 5 years, and fissure recurrence at 6 months and 5 years. RESULTS: A total of 59 patients received botulinum toxin injection (Botox), and 32 underwent lateral internal sphincterotomy. At 1 month after treatments, postoperative pain decreased faster and significantly more in the Botox group (30 vs. 60 mm; P<0.001); fissure re-epithelization was observed in 59.4% of the surgical group compared to 25.4% of Botox (P=0.0001). Anal sphincter pressures decreased more in surgical group (P=0.044), although severe anal incontinence was present only in this subset (6.2%; P=0.041). Compared to surgery, patients who received Botox had higher satisfaction rates (P<0.001). Fissure recurrence at 6 months was more common in Botox than surgical group (16.9% vs. 3.2%, respectively; P=0.053). The overall healing rate improved in all patients and persisted at 12 months and 5 years in both groups with overall high patient satisfaction despite mild anal incontinence in 21.8% in the surgery group (P<0.05). CONCLUSIONS: Botox, rather than surgery, should be considered the first-line treatment for chronic anal fissure.

Chronic intestinal pseudo-obstruction: associations with gut microbiota and genes expression of intestinal serotonergic pathway.

BACKGROUND: Pediatric chronic intestinal pseudo-obstruction (PIPO) is a rare disease characterized by symptoms and radiological signs suggestive of intestinal obstruction, in the absence of lumen-occluding lesions. It results from an extremely severe impairment of propulsive motility. The intestinal endocrine system (IES) jointly with the enteric nervous system (ENS) regulates secreto-motor functions via different hormones and bioactive messengers/neurotransmitters. The neurotransmitter 5-hydroxytryptamine (5-HT) (or serotonin) is linked to intestinal peristalsis and secretory reflexes. Gut microbiota and its interplay with ENS affect 5-HT synthesis, release, and the subsequent serotonin receptor activation. To date, the interplay between 5-HT and gut microbiota in PIPO remains largely unclear. This study aimed to assess correlations between mucosa associated microbiota (MAM), intestinal serotonin-related genes expression in PIPO. To this purpose, biopsies of the colon, ileum and duodenum have been collected from 7 PIPO patients, and 7 age-/sex-matched healthy controls. After DNA extraction, the MAM was assessed by next generation sequencing (NGS) of the V3-V4 region of the bacterial RNA 16 S, on an Illumina Miseq platform. The expression of genes implicated in serotoninergic pathway (TPH1, SLC6A4, 5-HTR3 and 5-HTR4) was established by qPCR, and correlations with MAM and clinical parameters of PIPO have been evaluated. RESULTS: Our results revealed that PIPO patients exhibit a MAM with a different composition and with dysbiosis, i.e. with a lower biodiversity and fewer less connected species with a greater number of non-synergistic relationships, compared to controls. qPCR results revealed modifications in the expression of serotonin-related intestinal genes in PIPO patients, when compared to controls. Correlation analysis do not reveal any kind of connection. CONCLUSIONS: For the first time, we report in PIPO patients a specific MAM associated to underlying pathology and an altered intestinal serotonin pathway. A possible dysfunction of the serotonin pathway, possibly related to or triggered by an altered microbiota, may contribute to dysmotility in PIPO patients. The results of our pilot study provide the basis for new biomarkers and innovative therapies targeting the microbiota or serotonin pathways in PIPO patients.

Chronic constipation in Parkinson's disease: clinical features and molecular insights on the intestinal epithelial barrier.

Background: Chronic constipation (CC) is a severe symptom in Parkinson's disease (PD), with an unclear pathogenesis. Abnormalities of the enteric nervous system (ENS) and/or intestinal epithelial barrier (IEB) may be pathophysiologically relevant in PD patients with CC. We investigated possible molecular changes of the IEB in PD/CCs compared with CCs and controls. Methods: Twelve PD/CCs (2 female, age range 51-80 years), 20 CCs (15 female, age range 27-78 years), and 23 controls (11 female, age range 32-74 years) were enrolled. Ten PD/CCs and 10 CCs were functionally characterized by anorectal manometry (AM) and transit time (TT). Colon biopsies were obtained and assessed for gene and protein expression, and localization of IEB tight junction markers claudin-4 (CLDN4), occludin-1 (OCCL-1), and zonula occludens-1 (ZO-1) by RT-qPCR, immunoblot and immunofluorescence labeling. Results: PD/CCs were clustered in 2 functional categories: patients with delayed TT and altered AM (60%), and a second group showing only modifications in AM pattern (40%). Gene expression of CLDN4, OCCL-1 and ZO-1 was higher in PD/CCs than controls (P<0.05). Conversely, PD/CCs showed a trend to decrease (P>0.05) in CLDN4 and OCCL-1 protein levels than controls, whereas ZO-1 protein was comparable. In PD/CCs compared with controls, decreasing tendency of vasoactive intestinal polypeptide mRNA, protein and immunoreactive fiber density were observed, although the difference was not statistically significant. Conclusion: Transit and anorectal dysfunctions in PD/CCs are associated with difference in ZO-1, OCCL-1 and CLDN4 expression, thus supporting the role of an altered IEB as a contributory mechanism to possible neuronal abnormalities.

Gluten and Wheat in Women's Health: Beyond the Gut.

Since the rise of awareness of gluten/wheat-related disorders in the academic and clinical field in the last few decades, misinformation regarding the gluten-free diet (GFD) and its impact on health has been spreading among the general population. Despite the established link between gluten and celiac disease (CD), where a GFD is mandatory to reach clinical and histological remission, things are more complicated when it comes to non-celiac gluten/wheat sensitivity (NCGWS) and other autoimmune/dysimmune disorders. In the last conditions, a beneficial effect of gluten withdrawal has not been properly assessed, but still is often suggested without strong supporting evidence. In this context, women have always been exposed, more than men, to higher social pressure related to nutritional behaviors and greater engagement in controlling body weight. With this narrative review, we aim to summarize current evidence on the adherence to a GFD, with particular attention to the impact on women's health.

Vasoactive Intestinal Polypeptide Plays a Key Role in the Microbial-Neuroimmune Control of Intestinal Motility.

BACKGROUND & AIMS: Although chronic diarrhea and constipation are common, the treatment is symptomatic because their pathophysiology is poorly understood. Accumulating evidence suggests that the microbiota modulates gut function, but the underlying mechanisms are unknown. We therefore investigated the pathways by which microbiota modulates gastrointestinal motility in different sections of the alimentary tract. METHODS: Gastric emptying, intestinal transit, muscle contractility, acetylcholine release, gene expression, and vasoactive intestinal polypeptide (VIP) immunoreactivity were assessed in wild-type and Myd88-/-Trif-/- mice in germ-free, gnotobiotic, and specific pathogen-free conditions. Effects of transient colonization and antimicrobials as well as immune cell blockade were investigated. VIP levels were assessed in human full-thickness biopsies by Western blot. RESULTS: Germ-free mice had similar gastric emptying but slower intestinal transit compared with specific pathogen-free mice or mice monocolonized with Lactobacillus rhamnosus or Escherichia coli, the latter having stronger effects. Although muscle contractility was unaffected, its neural control was modulated by microbiota by up-regulating jejunal VIP, which co-localized with and controlled cholinergic nerve function. This process was responsive to changes in the microbial composition and load and mediated through toll-like receptor signaling, with enteric glia cells playing a key role. Jejunal VIP was lower in patients with chronic intestinal pseudo-obstruction compared with control subjects. CONCLUSIONS: Microbial control of gastrointestinal motility is both region- and bacteria-specific; it reacts to environmental changes and is mediated by innate immunity-neural system interactions. By regulating cholinergic nerves, small intestinal VIP plays a key role in this process, thus providing a new therapeutic target for patients with motility disorders.

Distribution, quantification, and characterization of substance P enteric neurons in the submucosal and myenteric plexuses of the porcine colon.

The pig is an important translational model for studying intestinal physiology and disorders for its many homologies with humans, including the organization of the enteric nervous system (ENS), the major regulator of gastrointestinal functions. This study focused on the quantification and neurochemical characterization of substance P (SP) neurons in the pig ascending (AC) and descending colon (DC) in wholemount preparations of the inner submucosal plexus (ISP), outer submucosal plexus (OSP), and myenteric plexus (MP). We used antibodies for the pan-neuronal marker HuCD, and choline acetyltransferase (ChAT) and neuronal nitric oxide synthase (nNOS), markers for excitatory and inhibitory transmitters, for multiple labeling immunofluorescence and high-resolution confocal microscopy. The highest density of SP immunoreactive (IR) neurons was in the ISP (222/mm2 in the AC, 166/mm2 in the DC), where they make up about a third of HuCD-IR neurons, compared to the OSP and MP (19-22% and 13-17%, respectively, P < 0.001-0.0001). HuCD/SP/ChAT-IR neurons (up to 23%) were overall more abundant than HuCD/SP/nNOS-IR neurons (< 10%). Most SP-IR neurons contained ChAT-IR (62-85%), whereas 18-38% contained nNOS-IR with the highest peak in the OSP. A subpopulation of SP-IR neurons contains both ChAT- and nNOS-IR with the highest peak in the OSP and ISP of DC (33-36%) and the lowest in the ISP of AC (< 10%, P < 0.001). SP-IR varicose fibers were abundant in the ganglia. This study shows that SP-IR neurons are functionally distinct with variable proportions in different plexuses in the AC and DC reflecting diverse functions of specific colonic regions.

The Pro-Oncogenic Protein IF1 Promotes Proliferation of Anoxic Cancer Cells during Re-Oxygenation.

Cancer cells overexpress IF1, the endogenous protein that inhibits the hydrolytic activity of ATP synthase when mitochondrial membrane potential (ΔµH+) falls, as in ischemia. Other roles have been ascribed to IF1, but the associated molecular mechanisms are still under debate. We investigated the ability of IF1 to promote survival and proliferation in osteosarcoma and colon carcinoma cells exposed to conditions mimicking ischemia and reperfusion, as occurs in vivo, particularly in solid tumors. IF1-silenced and parental cells were exposed to the FCCP uncoupler to collapse ΔµH+ and the bioenergetics of cell models were validated. All the uncoupled cells preserved mitochondrial mass, but the implemented mechanisms differed in IF1-expressing and IF1-silenced cells. Indeed, the membrane potential collapse and the energy charge preservation allowed an increase in both mitophagy and mitochondrial biogenesis in IF1-expressing cells only. Interestingly, the presence of IF1 also conferred a proliferative advantage to cells highly dependent on oxidative phosphorylation when the uncoupler was washed out, mimicking cell re-oxygenation. Overall, our results indicate that IF1, by allowing energy preservation and promoting mitochondrial renewal, can favor proliferation of anoxic cells and tumor growth. Therefore, hindering the action of IF1 may be promising for the therapy of tumors that rely on oxidative phosphorylation for energy production.

Liquorice Toxicity: A Comprehensive Narrative Review.

BACKGROUND: Renowned since ancient times for its medical properties, liquorice is nowadays mainly used for flavoring candies or soft drinks. Continuous intake of large amounts of liquorice is a widely known cause of pseudo-hyperaldosteronism leading to hypertension and hypokalemia. These manifestations are usually mild, although in some cases may generate life-threatening complications, i.e., arrhythmias, muscle paralysis, rhabdomyolysis, and coma. In addition, liquorice has an important estrogenic-like activity. METHODS: We summarized the current knowledge about liquorice and reviewed 104 case reports in both the English and Italian languages from inception to June 2023 concerning complications due to an excess of liquorice intake. RESULTS: In contrast to most published data, female sex and old age do not appear to be risk factors. However, hypertension and electrolyte imbalance (mainly hypokalemia) are prevalent features. The detection of glycyrrhetinic acid in blood is very uncommon, and the diagnosis is essentially based on an accurate history taking. CONCLUSIONS: Although there is not a significant mortality rate, liquorice toxicity often requires hospitalization and therefore represents a significant health concern. Major pharmaceutical drug regulatory authorities should solicit public awareness about the potentially dangerous effects caused by excessive use of liquorice.

Comparison between Capillary and Serum Lactate Levels in Predicting Short-Term Mortality of Septic Patients at the Emergency Department.

Sepsis is a time-dependent and life-threating condition related to macro- and micro-circulatory impairment leading to anaerobic metabolism and lactate increase. We assessed the prognostic accuracy of capillary lactates (CLs) vs. serum ones (SLs) on 48-h and 7-day mortality in patients with suspected sepsis. This observational, prospective, single-centre study was conducted between October 2021 and May 2022. Inclusion criteria were: (i) suspect of infection; (ii) qSOFA ≥ 2; (iii) age ≥ 18 years; (iv) signed informed consent. CLs were assessed with LactateProTM2®. 203 patients were included: 19 (9.3%) died within 48 h from admission to the Emergency Department, while 28 (13.8%) within 7 days. Patients deceased within 48 h (vs. survived) had higher CLs (19.3 vs. 5 mmol/L, p < 0.001) and SLs (6.5 vs. 1.1 mmol/L, p = 0.001). The best CLs predictive cut-off for 48-h mortality was 16.8 mmol/L (72.22% sensitivity, 94.02% specificity). Patients within 7 days had higher CLs (11.5 vs. 5 mmol/L, p = 0.020) than SLs (2.75 vs. 1.1 mmol/L, p < 0.001). The multivariate analysis confirmed CLs and SLs as independent predictors of 48-h and 7-day mortality. CLs can be a reliable tool for their inexpensiveness, rapidity and reliability in identifying septic patients at high risk of short-term mortality.

Serum zonulin levels are increased in Alzheimer's disease but not in vascular dementia.

BACKGROUND: Zonulin is involved in the integrity and functioning of both intestinal-epithelial barrier and blood-brain barrier (BBB) by regulating tight junction molecular assembly. AIM: Since changes in microbiota and BBB may play a role in neurodegenerative disorders, we aimed to determine whether serum zonulin levels change in older patients affected by different types of dementia or mild cognitive impairment (MCI). METHODS: We evaluated serum zonulin levels in patients with late-onset AD (LOAD), vascular dementia (VAD), MIXED (AD + VAD) dementia, amnestic MCI, and in healthy controls. RESULTS: Compared with controls, serum zonulin increased in LOAD, MIXED dementia, and aMCI but not in VAD, independent of potential confounders (ANCOVA p = 0.01; LOAD vs controls, p = 0.01; MIXED vs. controls, p = 0.003; aMCI vs. controls, p = 0.04). Notably, aMCI converting to dementia showed significantly higher levels of zonulin compared with stable aMCI (p = 0.04). Serum zonulin inversely correlated with the standardized Mini-Mental State Examination (MMSE) score (p < 0.05), regardless of potential confounders. DISCUSSION: We found increased serum zonulin levels in patients with aMCI, LOAD and MIXED dementia, but not in VAD; moreover, zonulin levels were higher in aMCI converting to AD compared with stable ones. CONCLUSIONS: Our findings suggest that a dysregulation of intestinal-epithelial barrier and/or BBB may be an early specific event in AD-related neurodegeneration.

Markers of liver function as potential prognostic indicators of SARS-CoV-2 infection: A retrospective analysis during the first and second waves of COVID-19 pandemic.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is known to cause a predominant respiratory disease, although extrapulmonary manifestations can also occur. One of the targets of Coronavirus disease 2019 (COVID-19) is the hepatobiliary system. The present study aims to describe the correlation between the increase of liver damage markers (i.e. alanine aminotransferase [ALT], aspartate aminotransferase [AST], total bilirubin [TB]) and COVID-19 outcomes (i.e., in-hospital mortality [IHM] and intensive care unit [ICU] transfer). Methods: All patients with confirmed SARS-CoV-2 infection admitted to the Infectious Diseases Unit of the St. Anna University-Hospital of Ferrara from March 2020 to October 2021 were retrospectively included in this single-centre study. ALT, AST and TB levels were tested in all patients and IHM or ICU transfer were considered as main outcomes. Co-morbidities were assessed using Charlson Comorbidity Index. Results: A total of 106 patients were retrieved. No hepatic marker was able to predict IHM, whereas all of them negatively predicted ICU transfer (ALT: OR 1.005, 95%CI 1.001-1.009, p= 0.011; AST: OR 1.018, 95%CI 1.006-1.030, p= 0.003; TB: OR 1.329, 95%CI 1.025-1.724, p= 0.032). Age was the only parameter significantly related to mortality. Conclusions: The present study, by correlating liver damage markers with COVID-19 outcome, showed that an increase of ALT, AST and TB predicted patients' severity, although not mortality.

Acute Prosthetic Joint Infections with Poor Outcome Caused by Staphylococcus Aureus Strains Producing the Panton-Valentine Leukocidin.

The aim of this study was to investigate whether the presence of Staphylococcus aureus (SA) producing the Panton-Valentine leukocidin (PVL) affects the outcome of Prosthetic Joint Infection (PJI). Patients with acute and chronic PJI sustained by SA were prospectively enrolled at the orthopedic unit of "Casa di Cura Santa Maria Maddalena", from January 2019 to October 2021. PJI diagnosis was reached according to the diagnostic criteria of the International Consensus Meeting on PJI of Philadelphia. Synovial fluid obtained via joint aspirations was collected in order to isolate SA. The detection of PVL was performed via real-time quantitative PCR (RT-qPCR). The outcome assessment was performed using the criteria of the Delphi-based International Multidisciplinary Consensus. Twelve cases of PJI caused by SA were included. Nine (75%) cases were acute PJI treated using debridement, antibiotic and implant retention (DAIR); the remaining three (25%) were chronic PJI treated using two-stage (n = 2) and one-stage revision (n = 1), respectively. The SA strains that tested positive for PVL genes were 5/12 (41.6%,). Treatment failure was documented in three cases of acute PJI treated using DAIR, all supported by SA-PVL strains (p < 0.045). The remaining two cases were chronic PJI treated with a revision arthroplasty (one and two stage, respectively), with a 100% eradication rate in a medium follow-up of 24 months. Although a small case series, our study showed a 100% failure rate in acute PJI, probably caused by SA PVL-producing strains treated conservatively (p < 0.04). In this setting, toxin research should guide radical surgical treatment and targeted antibiotic therapy.

Osteoporosis and Celiac Disease: Updates and Hidden Pitfalls.

Celiac disease (CD) is an autoimmune disorder caused by gluten ingestion in genetically predisposed individuals. In addition to the typical gastrointestinal symptoms (e.g., diarrhea, bloating, and chronic abdominal pain), CD may also present with a broad spectrum of manifestations, including low bone mineral density (BMD) and osteoporosis. The etiopathology of bone lesions in CD is multifactorial and other conditions, rather than mineral and vitamin D malabsorption, may affect skeletal health, especially those related to the endocrine system. Here, we describe CD-induced osteoporosis in an attempt to enlighten new and less-known aspects, such as the influence of the intestinal microbiome and sex-related differences on bone health. This review describes the role of CD in the development of skeletal alterations to provide physicians with an updated overview on this debated topic and to improve the management of osteoporosis in CD.

Impact of Female Gender in Inflammatory Bowel Diseases: A Narrative Review.

Inflammatory bowel diseases show a gender bias, as reported for several other immune-mediated diseases. Female-specific differences influence disease presentation and activity, leading to a different progression between males and females. Women show a genetic predisposition to develop inflammatory bowel disease related to the X chromosome. Female hormone fluctuation influences gastrointestinal symptoms, pain perception, and the state of active disease at the time of conception could negatively affect the pregnancy. Women with inflammatory bowel disease report a worse quality of life, higher psychological distress, and reduced sexual activity than male patients. This narrative review aims to resume the current knowledge of female-related features in clinical manifestations, development, and therapy, as well as sexual and psychological implications related to inflammatory bowel disease. The final attempt is to provide gastroenterologists with a roadmap of female-specific differences, to improve patients' diagnosis, management, and treatment.

Presepsin levels and COVID-19 severity: a systematic review and meta-analysis.

Plasmatic presepsin (PSP) is a novel biomarker reported to be useful for sepsis diagnosis and prognosis. During the pandemic, only few studies highlighted a possible correlation between PSP and COVID-19 severity, but results remain inconsistent. The present study aims to establish the correlation between PSP and COVID-19 severity. English-language papers assessing a correlation between COVID-19 and PSP from MEDLINE, PubMed, Google Scholar, Cochrane Library, MeSH, LitCovid NLM, EMBASE, CINAHL Plus and the World Health Organization (WHO) website, published from January 2020 were considered with no publication date limitations. Two independent reviewers performed data abstraction and quality assessment, and one reviewer resolved inconsistencies. The protocol was registered on PROSPERO (CRD42022325971).Fifteen articles met our eligibility criteria. The aggregate study population included 1373 COVID-19 patients who had undergone a PSP assessment. The random-effect meta-analysis was performed in 7 out of 15 selected studies, considering only those reporting the mean PSP levels in low- and high-severity cases (n = 707).The results showed that the pooled mean difference of PSP levels between high- and low-severity COVID-19 patients was 441.70 pg/ml (95%CI: 150.40-732.99 pg/ml).Our data show that presepsin is a promising biomarker that can express COVID-19 severity.

Enteric Neuromyopathies: Highlights on Genetic Mechanisms Underlying Chronic Intestinal Pseudo-Obstruction.

Severe gut motility disorders are characterized by the ineffective propulsion of intestinal contents. As a result, the patients develop disabling/distressful symptoms, such as nausea and vomiting along with altered bowel habits up to radiologically demonstrable intestinal sub-obstructive episodes. Chronic intestinal pseudo-obstruction (CIPO) is a typical clinical phenotype of severe gut dysmotility. This syndrome occurs due to changes altering the morpho-functional integrity of the intrinsic (enteric) innervation and extrinsic nerve supply (hence neuropathy), the interstitial cells of Cajal (ICC) (mesenchymopathy), and smooth muscle cells (myopathy). In the last years, several genes have been identified in different subsets of CIPO patients. The focus of this review is to cover the most recent update on enteric dysmotility related to CIPO, highlighting (a) forms with predominant underlying neuropathy, (b) forms with predominant myopathy, and (c) mitochondrial disorders with a clear gut dysfunction as part of their clinical phenotype. We will provide a thorough description of the genes that have been proven through recent evidence to cause neuro-(ICC)-myopathies leading to abnormal gut contractility patterns in CIPO. The discovery of susceptibility genes for this severe condition may pave the way for developing target therapies for enteric neuro-(ICC)-myopathies underlying CIPO and other forms of gut dysmotility.

Pharmacological characterization of naloxegol: In vitro and in vivo studies.

Opioid-induced constipation is the most prevalent adverse effect of opioid drugs. Peripherally acting mu opioid receptor antagonists (PAMORAs), including naloxegol, are indicated for the treatment of opioid-induced constipation. The aim of this study was the in vitro and in vivo pharmacological characterization of naloxegol in comparison with naloxone. In vitro experiments were performed to measure calcium mobilization in cells coexpressing opioid receptors and chimeric G proteins and mu receptor interaction with G protein and ß-arrestin 2 using bioluminescence resonance energy transfer. In vivo experiments were performed in mice to measure pain threshold using the tail withdrawal assay and colonic transit using the bead expulsion assay. In vitro, naloxegol behaved as a selective and competitive mu receptor antagonist similarly to naloxone, being 3-10-fold less potent. In vivo, naloxone was effective in blocking fentanyl actions when given subcutaneously (sc), but not per os (po). In contrast, naloxegol elicited very similar effects with sc or po administration counteracting in a dose dependent manner the constipating effects of fentanyl without interfering with the fentanyl mediated analgesia. Thus, a useful PAMORA action could be obtained with naloxegol both after po and sc administration.

Biased versus Partial Agonism in the Search for Safer Opioid Analgesics.

Opioids such as morphine-acting at the mu opioid receptor-are the mainstay for treatment of moderate to severe pain and have good efficacy in these indications. However, these drugs produce a plethora of unwanted adverse effects including respiratory depression, constipation, immune suppression and with prolonged treatment, tolerance, dependence and abuse liability. Studies in ß-arrestin 2 gene knockout (ßarr2(-/-)) animals indicate that morphine analgesia is potentiated while side effects are reduced, suggesting that drugs biased away from arrestin may manifest with a reduced-side-effect profile. However, there is controversy in this area with improvement of morphine-induced constipation and reduced respiratory effects in ßarr2(-/-) mice. Moreover, studies performed with mice genetically engineered with G-protein-biased mu receptors suggested increased sensitivity of these animals to both analgesic actions and side effects of opioid drugs. Several new molecules have been identified as mu receptor G-protein-biased agonists, including oliceridine (TRV130), PZM21 and SR-17018. These compounds have provided preclinical data with apparent support for bias toward G proteins and the genetic premise of effective and safer analgesics. There are clinical data for oliceridine that have been very recently approved for short term intravenous use in hospitals and other controlled settings. While these data are compelling and provide a potential new pathway-based target for drug discovery, a simpler explanation for the behavior of these biased agonists revolves around differences in intrinsic activity. A highly detailed study comparing oliceridine, PZM21 and SR-17018 (among others) in a range of assays showed that these molecules behave as partial agonists. Moreover, there was a correlation between their therapeutic indices and their efficacies, but not their bias factors. If there is amplification of G-protein, but not arrestin pathways, then agonists with reduced efficacy would show high levels of activity at G-protein and low or absent activity at arrestin; offering analgesia with reduced side effects or 'apparent bias'. Overall, the current data suggests-and we support-caution in ascribing biased agonism to reduced-side-effect profiles for mu-agonist analgesics.