Expert Review of Gastroenterology & Hepatology最新文献

Introduction: Alagille syndrome (ALGS) is an autosomal dominant, multisystem genetic disorder with wide phenotypic variability caused by mutations in the Notch signaling pathway, specifically from mutations in either the Jagged1 (JAG1) or NOTCH2 gene. The range of clinical features in ALGS can involve various organ systems including the liver, heart, eyes, skeleton, kidney, and vasculature. Despite the genetic mutations being well-defined, there is variable expressivity and individuals with the same mutation may have different clinical phenotypes.

Areas covered: While no clear genotype-phenotype correlation has been identified in ALGS, this review will summarize what is currently known about the genotype-phenotype relationship and how this relationship influences the treatment of the multisystemic disorder. This review includes discussion of numerous studies which have focused on describing the genotype-phenotype relationship of different organ systems in ALGS as well as relevant basic science and population studies of ALGS. A thorough literature search was completed via the PubMed and National Library of Medicine GeneReviews databases including dates from 1969, when ALGS was first identified, to February 2023.

Expert opinion: The genetics of ALGS are well defined; however, ongoing investigation to identify genotype-phenotype relationships as well as genetic modifiers as potential therapeutic targets is needed. Clinicians and patients alike would benefit from identification of a correlation to aid in diagnostic evaluation and management.

Background and aims: Tolvaptan has been approved for the management of cirrhosis-related complications according to the Japanese and Chinese practice guidelines, but not the European or American practice guidelines in view of FDA warning about its hepatotoxicity. This study aimed to systematically evaluate its efficacy and safety in cirrhosis.

Methods: The PubMed, EMBASE, and Cochrane library databases were searched to identify randomized controlled trials (RCTs) evaluating the efficacy and/or safety of tolvaptan in cirrhosis. Risk ratios (RRs) and weight mean differences (WMDs) were calculated. The incidence of common adverse events (AEs) was pooled.

Results: Eight RCTs were included. Tolvaptan was significantly associated with higher rates of improvement of ascites (RR = 1.49, P < 0.001) and hyponatremia (RR = 1.80, P = 0.005) and incidence of any AEs (RR = 1.18, P = 0.003), but not serious AEs (RR = 0.86, P = 0.410). Tolvaptan was significantly associated with reductions in body weight (WMD = -1.30 kg, P < 0.001) and abdominal circumference (WMD = -1.71 cm, P < 0.001), and increases in daily urine volume (WMD = 1299.84 mL, P < 0.001) and serum sodium concentration (WMD = 2.57 mmol/L, P < 0.001). The pooled incidences of dry mouth, thirst, constipation, and pollakiuria were 16%, 24%, 6%, and 17%, respectively.

Conclusion: Short-term use of tolvaptan may be considered in cirrhotic patients with ascites who have inadequate response to conventional diuretics and those with hyponatremia.

Introduction: The number of people diagnosed with inflammatory bowel disease (IBD) continues to increase in most parts of the world. Although the exact etiology of this chronic intestinal disease is not fully understood, nutritional factors appear to play key roles. Furthermore, individuals with IBD are at increased risk of adverse nutritional impacts, including micronutrient deficiencies.

Areas covered: This review aims to summarize recent reports focusing on nutritional factors relevant to the development of IBD and to also review data on nutritional deficiencies seen in individuals with IBD.

Expert opinion: The typical western diet, characterized by high-fat/high-sugar foods, along with food additives, appears to contribute to the etiopathogenesis of IBD. In contrast, some reports indicate that some foods are likely protective. However, there are inconsistencies in the currently available data, reflecting study design and other confounding factors. Furthermore, some of the conclusions are inferred from animal or in vitro studies. The presence of IBD can compromise the nutrition of individuals with one of these disorders: ongoing monitoring is critical. Nutrition and diet in the setting of IBD remain key areas for further and ongoing study.

Introduction: Gut microbiota produces thousands of metabolites, which have a huge impact on the host health. Specific microbial strains are able to synthesize histamine, a molecule with a crucial role in many physiologic and pathologic mechanisms of the host. This function is mediated by the histidine decarboxylase enzyme (HDC) that converts the amino acid histidine to histamine.

Areas covered: This review summarizes the emerging data on histamine production by gut microbiota, and the effect of bacterial-derived histamine in different clinical contexts, including cancer, irritable bowel syndrome, and other gastrointestinal and extraintestinal pathologies. This review will also outline the impact of histamine on the immune system and the effect of probiotics that can secrete histamine. Search methodology: we searched the literature on PubMed up to February 2023.

Expert opinion: The potential of modulating gut microbiota to influence histamine production is a promising area of research, and although our knowledge of histamine-secreting bacteria is still limited, recent advances are exploring their diagnostic and therapeutical potential. Diet, probiotics, and pharmacological treatments directed to the modulation of histamine-secreting bacteria may in the future potentially be employed in the prevention and management of several gastrointestinal and extraintestinal disorders.

Introduction: The intestinal barrier is a multi-faced structure lining the surface of the intestinal mucosa of the GI tract. To exert its main functions as a physical and immunological defense barrier, several components of the intestinal barrier act in a concerted and cooperative manner.

Areas covered: Herein, we first introduce to the basic organization of the intestinal barrier and then summarize different methods to assess barrier function in and ex vivo. Finally, we provide an in-depth overview of the relevance of intestinal barrier dysfunction in inflammatory bowel diseases.

Expert opinion: In parallel to a more fundamental understanding of the intestinal barrier as a key component for intestinal integrity is the notion that intestinal barrier defects are associated with a variety of diseases such as inflammatory bowel diseases. Recent research has fueled and perpetuated the concept that barrier defects are critical components of disease development, disease behavior, and potentially also an area of therapeutic intervention in IBD patients. Although being far away from standard, new technologies can be used to easily assess barrier healing in IBD and to derive clinical consequences from these findings such as more accurate forecasting of future disease behavior or the identification of novel therapeutic targets.

Introduction: Children and adolescents with Crohn's disease present unique challenges due to extensive disease at diagnosis and the effect of bowel inflammation on growth. Historical approaches with corticosteroids and immunomodulators are far less effective than early treatment with anti-TNF biologics.

Areas covered: This review covers recent literature delineating the crucial role of early anti-TNF therapy in the treatment of moderate- to- severe Crohn's disease in children and adolescents. The potential risks and benefits of concomitant immunomodulators are discussed, along with therapeutic anti-TNF drug monitoring, and reassessment by endoscopy and cross-sectional imaging to evaluate success beyond symptom control.

Expert opinion: Standard of care therapy for moderate-to-severe pediatric Crohn's disease now entails precision dosing of anti-TNF therapy with periodic reassessment of bowel inflammation. The role of dietary modification continues to evolve. Current and future efforts need to be directed to elucidating ways to predict response to anti-TNF therapy and quickly changing to agents with other mechanisms of action when needed. Inordinate regulatory delays in approval of new therapies approved for adults continue to handicap pediatric clinicians and frequently limits their treatment choices, or forces them to give medications "off label." Only a concerted effort by clinicians, pharma, and regulators will improve this situation.

Introduction: Kidney is the most common extra-hepatic organ involved in patients with advanced liver cirrhosis and acute-on-chronic liver failure. Hepatorenal syndrome-acute kidney injury (HRS-AKI) accounts for most hospitalizations, and liver transplantation (LT) remains the ultimate and long-term treatment in such patients. However, HRS-AKI, being a functional renal failure, has a fair chance of reversal, and as such, patients who achieve reversal of HRS-AKI have better outcomes post-LT.

Areas covered: In this review, we discuss the pharmacokinetics, pharmacodynamics and evidence to support the use of terlipressin in HRS-AKI while we also address predictors of response and the associated adverse events. Further, we discuss the role of terlipressin in the context of LT.

Expert opinion: The recommended treatment for HRS-AKI reversal includes a vasoconstrictor in addition to volume expansion with albumin. The three vasoconstrictor regimens generally used to treat HRS-AKI include octreotide plus midodrine, noradrenaline, and terlipressin. Of these, terlipressin is a widely used drug and has been recently approved by US Food and Drug Administration (USFDA) for HRS-AKI. Terlipressin is the most effective drug for HRS-AKI reversal and is associated with a decreased need for renal replacement therapy pre- and post-transplant. Furthermore, terlipressin responders have improved transplant-free and post-transplant survival.

Introduction: Along with the rising prevalence of inflammatory bowel disease (IBD) [Crohn's disease (CD) and ulcerative colitis (UC)], biological therapies need an update/insight.

Area covered: This review included randomized controlled trials (RCTs) from PubMed database (2000-October 2022) of approved biologics and small molecules with primary outcome analysis on efficacy (clinical response/remission/mucosal healing) and/or adverse events (AEs). Considered for this review under biologics classes are TNF-α inhibitors, leukocyte trafficking inhibitors, and anti IL-12/IL-23; and under small molecules are Janus-kinase inhibitors, and sphingosine-1-phosphate receptor modulators.

Expert opinion: In CD, clinical response and remission were better with tofacitinib (61.23%) and infliximab (44.86%), respectively, in the induction phase, and these were better with ustekinumab in the maintenance phase. In UC, the maximum rate of response, remission, and mucosal healing were obtained with infliximab during the induction phase (67.49%, 35.99%, and 60.25%, respectively). During the maintenance phase, response rate was better with ustekinumab, but remission and mucosal healing were better with vedolizumab. The combined percentage of AEs was highest with infliximab (174.45%) and least with ozanimod (23.04%), and most commonly belonged to the 'infection and infestation system organ class (SOC).' These efficacy and safety analyses will help in the optimization of biologic treatment in IBD.