Investigation of autonomic function and orocecal transit time in patients with nonalcoholic cirrhosis and the potential influence of these factors on disease outcome

Leaky Gut and Gut-Liver Axis in Liver Cirrhosis: Clinical Studies Update

Portal blood flows into the liver containing the gut microbiome and its products such as endotoxin and bacterial DNA. The cirrhotic liver acts and detoxifies as the initial site of microbial products. In so-called "leaky gut," the increased intestinal permeability for bacteria and their products constitutes an important pathogenetic factor for major complications in patients with liver cirrhosis. Prolonged gastric and small intestinal transit may induce intestinal bacterial overgrowth, a condition in which colonic bacteria translocate into the small gut. Cirrhotic patients further show gut dysbiosis characterized by an overgrowth of potentially pathogenic bacteria and a decrease in autochthonous nonpathogenic bacteria. Pathological bacterial translocation (BT) is a contributing factor in the development of various severe complications. Bile acids (BAs) undergo extensive enterohepatic circulation and play important roles in the gut-liver axis. BT-induced inflammation prevents synthesis of BAs in the liver through inhibition of BA-synthesizing enzyme CYP7A1. A lower abundance of 7α-dehydroxylating gut bacteria leads to decreased conversion of primary to secondary BAs. Decreases in total and secondary BAs may play an important role in the gut dysbiosis characterized by a proinflammatory and toxic gut microbiome inducing BT and endotoxemia, as addressed in my previous reviews. Selective intestinal decontamination by the use of various antimicrobial drugs for management of complications has a long history. Lactobacillus GG decreasing endotoxemia is reported to improve the microbiome with beneficial changes in amino acid, vitamin and secondary BA metabolism. Current approaches for hepatic encephalopathy are the use of nonabsorbable antibiotics and disaccharides. Probiotics may become an additional therapeutic option for advanced liver cirrhosis.

Heart rate variability in patients with cirrhosis: a systematic review and meta-analysis

Background. Cirrhosis is associated with abnormal autonomic function and regulation of cardiac rhythm. Measurement of heart rate variability (HRV) provides an accurate and non-invasive measurement of autonomic function as well as liver disease severity currently calculated using the MELD, UKELD, or Child-Pugh scores. This review assesses the methods employed for the measurement of HRV, and evaluates the alteration of HRV indices in cirrhosis, as well as their value in prognosis.Method.We undertook a systematic review using Medline, Embase and Pubmed databases in July 2020. Data were extracted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias of the included studies was assessed by a modified version of the Newcastle-Ottawa Scale. The descriptive studies were analysed and the standardized mean differences of HRV indices were pooled.Results.Of the 247 studies generated from our search, 14 studies were included. One of the 14 studies was excluded from meta-analysis because it reported only the median of HRV indices. The studies included have a low risk of bias and include 583 patients with cirrhosis and 349 healthy controls. The HRV time and frequency domains were significantly lower in cirrhotic patients. Between-studies heterogeneity was high in most of the pooled studies (P < 0.05). Further, HRV indices predict survival independent of the severity of liver disease as assessed by MELD.Conclusion.HRV is decreased in patients with cirrhosis compared with healthy matched controls. HRV correlated with severity of liver disease and independently predicted survival. There was considerable variation in the methods used for HRV analysis, and this impedes interpretation and clinical applicability. Based on the data analysed, the standard deviation of inter-beat intervals (SDNN) and SDNN corrected for basal heart rate (cSDNN) are the most suitable indices for prognosis in patients with cirrhosis.

Intestinal permeability and bacterial translocation in patients with liver disease, focusing on alcoholic aetiology: methods of assessment and therapeutic intervention

Increased bacterial translocation (BT) across the gut barrier due to greater intestinal permeability (IP) is seen across a range of conditions, including alcohol-related liver disease (ArLD). The phenomenon of BT may contribute to both the pathogenesis and the development of complications in ArLD. There are a number of methods available to assess IP and in this review we look at their various advantages and limitations. The knowledge around BT and IP in ArLD is also reviewed, as well as the therapeutic strategies currently in use and in development.

Small intestinal dysmotility in cirrhotic patients: correlation with severity of liver disease and cirrhosis-associated complications

INTRODUCTION

 Altered small intestinal motility has been observed in various manometry studies in patients with cirrhosis. Since small bowel manometry is available only in a few centers, interpretation of dysmotility in cirrhosis is controversial.

PATIENTS AND METHODS

 In this study, both fasting and postprandial manometric tracings of 24-hour antroduodenojejunal manometries were analyzed using both visual analysis and computer-aided analysis.

RESULTS

 In 34 patients (83 %), the mean migrating motor complex (MMC) cycle length was different compared with healthy controls. Phase II was prolonged in 27 patients (66 %), while phase I showed a reduced duration in 23 (56 %) and in phase III in 13 individuals (32 %). We also observed special motor patterns, e. g., migrating clustered contractions (MCCs) or retrograde clustered contractions (RCCs), which were present during fasting (69 %) and postprandial (92 %) motility, while none of the healthy controls showed any special motor patterns. Special motor patterns showed a significant correlation with the severity of cirrhosis (Child-Score; p > 0.05) and the existence of ascites (p < 0.05).

DISCUSSION

 This study in a large cohort of patients with cirrhosis by using 24-hour, solid state portable manometry showed in most individuals disturbances of cyclic fasting motility. Special motor patterns like RCCs during fasting and postprandial motility could be observed exclusively in the cirrhosis group, showing a significant correlation with severity of cirrhosis and the occurence of associated complications.

Small Intestinal Bacterial Overgrowth in Patients With Cirrhosis

Small intestinal bacterial overgrowth (SIBO) is defined by increased density and/or abnormal composition of microbiota in the small bowel. SIBO is often encountered in patients with cirrhosis as a result of impaired intestinal motility and delayed transit time, both of which are exacerbated by more severe liver disease. Additional risk factors for SIBO commonly encountered in cirrhotic patients include coexisting diabetes, autonomic neuropathy, and/or alcoholic use. Diagnosis of SIBO is performed by breath testing or jejunal aspiration, the gold standard. In cirrhotic patients, the presence of SIBO can lead to profound clinical consequences. Increased intestinal permeability in these patients predisposes to bacterial translocation into the systemic circulation. As a result, SIBO is implicated as a significant risk factor in the pathogenesis of both spontaneous bacterial peritonitis and hepatic encephalopathy in cirrhotics. Antibiotics, especially rifaximin, are the best studied and most effective treatment options for SIBO. However, prokinetics, probiotics, nonselective beta-blockers, and treatment of underlying liver-related pathophysiology with transjugular intrahepatic portosystemic shunt placement or liver transplantation are also being investigated. This review will discuss the risk factors, diagnosis, manifestations in cirrhosis, and treatment options of SIBO.

Gastrointestinal Motility Disorders and Their Clinical Implications in Cirrhosis

Gastrointestinal motility is impaired in a substantial proportion of patients with cirrhosis. Cirrhosis-related autonomic neuropathy, increased nitric oxide production, and gut hormonal changes have been implicated. Oesophageal dysmotility has been associated with increased frequency of abnormal gastro-oesophageal reflux. Impaired gastric emptying and accommodation may result in early satiety and may have an impact on the nutritional status of these patients. Small intestinal dysmotility might be implicated in small intestinal bacterial overgrowth and increased bacterial translocation. The latter has been implicated in the pathophysiology of hepatic encephalopathy and spontaneous bacterial peritonitis. Enhanced colonic motility is usually associated with the use of lactulose. Pharmacological interventions aiming to alter gastrointestinal motility in cirrhosis could potentially have a beneficial effect reducing the risk of hepatic decompensation and improving prognosis.

Changes of Intestinal Functions in Liver Cirrhosis

Background

Understanding of the gut-liver axis is important for the up-to-date management of liver cirrhosis, and changes of intestinal functions form the core of this interesting research field.

Summary

Most investigators noted small intestinal dysmotility in their patients with liver cirrhosis. Marked changes in the contraction pattern were observed in early manometric studies. The orocecal transit time, particularly small intestinal transit, has generally been reported to be prolonged, which has been demonstrated in multiple investigations to be related to the severity of the liver disease (e.g., Child-Pugh class), the presence of small intestinal bacterial overgrowth (SIBO) and hepatic encephalopathy (HE) as well as a history of spontaneous bacterial peritonitis. Bacteriologically proven SIBO in proximal jejunal aspiration has been reported to be present in up to 59% of cirrhotic patients and is associated with systemic endotoxemia. Clinical and experimental studies suggest that delayed small bowel transit in liver cirrhosis may lead to SIBO, which could contribute to the symptoms of abdominal pain and diarrhea. In addition to autonomic neuropathy, metabolic derangements and diabetic state, SIBO itself may delay intestinal transit in cirrhotic patients. Several studies, both from the West and the East, have shown that the gut microbiota is altered in cirrhotic patients and particularly those with HE. Further, a quantitative change in Bacteroides/Firmicutes ratio, with a prevalence of potentially pathogenic bacteria (e.g., Enterobacteriaceae) and reduction in specific commensals (e.g., Lachnospiraceae), has been described. Structural and functional changes in the intestinal mucosa that contribute to increases in intestinal permeability for bacteria and their products have been observed in patients with liver cirrhosis, which is considered as an important pathogenetic factor for several complications. The mechanism of intestinal barrier dysfunction in cirrhosis is multifactorial, including alcohol, portal hypertension (vascular congestion and dysregulation), endotoxemia, SIBO, local inflammation and, most likely, immunological factors and medications.

Key Messages

This review summarizes major achievements regarding intestinal dysfunction in cirrhosis for future gastroenterology research. The question of whether this intestinal barrier dysfunction is accompanied and/or at least partly caused by structural and functional changes in the epithelial tight junction proteins is as yet unsolved. Development of new strategies to modulate gut-liver interaction is urgently needed.

Changes of Intestinal Functions in Liver Cirrhosis

BACKGROUND

Understanding of the gut-liver axis is important for the up-to-date management of liver cirrhosis, and changes of intestinal functions form the core of this interesting research field.

SUMMARY

Most investigators noted small intestinal dysmotility in their patients with liver cirrhosis. Marked changes in the contraction pattern were observed in early manometric studies. The orocecal transit time, particularly small intestinal transit, has generally been reported to be prolonged, which has been demonstrated in multiple investigations to be related to the severity of the liver disease (e.g., Child-Pugh class), the presence of small intestinal bacterial overgrowth (SIBO) and hepatic encephalopathy (HE) as well as a history of spontaneous bacterial peritonitis. Bacteriologically proven SIBO in proximal jejunal aspiration has been reported to be present in up to 59% of cirrhotic patients and is associated with systemic endotoxemia. Clinical and experimental studies suggest that delayed small bowel transit in liver cirrhosis may lead to SIBO, which could contribute to the symptoms of abdominal pain and diarrhea. In addition to autonomic neuropathy, metabolic derangements and diabetic state, SIBO itself may delay intestinal transit in cirrhotic patients. Several studies, both from the West and the East, have shown that the gut microbiota is altered in cirrhotic patients and particularly those with HE. Further, a quantitative change in Bacteroides/Firmicutes ratio, with a prevalence of potentially pathogenic bacteria (e.g., Enterobacteriaceae) and reduction in specific commensals (e.g., Lachnospiraceae), has been described. Structural and functional changes in the intestinal mucosa that contribute to increases in intestinal permeability for bacteria and their products have been observed in patients with liver cirrhosis, which is considered as an important pathogenetic factor for several complications. The mechanism of intestinal barrier dysfunction in cirrhosis is multifactorial, including alcohol, portal hypertension (vascular congestion and dysregulation), endotoxemia, SIBO, local inflammation and, most likely, immunological factors and medications.

KEY MESSAGES

This review summarizes major achievements regarding intestinal dysfunction in cirrhosis for future gastroenterology research. The question of whether this intestinal barrier dysfunction is accompanied and/or at least partly caused by structural and functional changes in the epithelial tight junction proteins is as yet unsolved. Development of new strategies to modulate gut-liver interaction is urgently needed.

Changes of Intestinal Functions in Liver Cirrhosis

Background

Understanding of the gut-liver axis is important for the up-to-date management of liver cirrhosis, and changes of intestinal functions form the core of this interesting research field.

Summary

Most investigators noted small intestinal dysmotility in their patients with liver cirrhosis. Marked changes in the contraction pattern were observed in early manometric studies. The orocecal transit time, particularly small intestinal transit, has generally been reported to be prolonged, which has been demonstrated in multiple investigations to be related to the severity of the liver disease (e.g., Child-Pugh class), the presence of small intestinal bacterial overgrowth (SIBO) and hepatic encephalopathy (HE) as well as a history of spontaneous bacterial peritonitis. Bacteriologically proven SIBO in proximal jejunal aspiration has been reported to be present in up to 59% of cirrhotic patients and is associated with systemic endotoxemia. Clinical and experimental studies suggest that delayed small bowel transit in liver cirrhosis may lead to SIBO, which could contribute to the symptoms of abdominal pain and diarrhea. In addition to autonomic neuropathy, metabolic derangements and diabetic state, SIBO itself may delay intestinal transit in cirrhotic patients. Several studies, both from the West and the East, have shown that the gut microbiota is altered in cirrhotic patients and particularly those with HE. Further, a quantitative change in Bacteroides/Firmicutes ratio, with a prevalence of potentially pathogenic bacteria (e.g., Enterobacteriaceae) and reduction in specific commensals (e.g., Lachnospiraceae), has been described. Structural and functional changes in the intestinal mucosa that contribute to increases in intestinal permeability for bacteria and their products have been observed in patients with liver cirrhosis, which is considered as an important pathogenetic factor for several complications. The mechanism of intestinal barrier dysfunction in cirrhosis is multifactorial, including alcohol, portal hypertension (vascular congestion and dysregulation), endotoxemia, SIBO, local inflammation and, most likely, immunological factors and medications.

Key Messages

This review summarizes major achievements regarding intestinal dysfunction in cirrhosis for future gastroenterology research. The question of whether this intestinal barrier dysfunction is accompanied and/or at least partly caused by structural and functional changes in the epithelial tight junction proteins is as yet unsolved. Development of new strategies to modulate gut-liver interaction is urgently needed.

Gastrointestinal dysfunction in liver cirrhosis

Patients with liver cirrhosis exhibit several features of gut dysfunction which may contribute to the development of cirrhosis complications as well as have an impact on nutritional status and health-related quality of life. Gastrointestinal symptoms are common in cirrhosis and their pathophysiology probably involves factors related to liver disease severity, psychological distress, and gut dysfunction (e.g., increased gastric sensitivity to distension and delayed gut transit). They may lead to reduced food intake and, thus, may contribute to the nutritional status deterioration in cirrhotic patients. Although tense ascites appears to have a negative impact on meal-induced accommodation of the stomach, published data on gastric accommodation in cirrhotics without significant ascites are not unanimous. Gastric emptying and small bowel transit have generally been shown to be prolonged. This may be related to disturbances in postprandial glucose, insulin, and ghrelin levels, which, in turn, appear to be associated to insulin resistance, a common finding in cirrhosis. Furthermore, small bowel manometry disturbances and delayed gut transit may be associated with the development of small bowel bacterial overgrowth. Finally, several studies have reported intestinal barrier dysfunction in patients with cirrhosis (especially those with portal hypertension), which is related to bacterial translocation and permeation of intestinal bacterial products, e.g., endotoxin and bacterial DNA, thus potentially being involved in the pathogenesis of complications of liver cirrhosis.

What does irritable bowel syndrome share with non-alcoholic fatty liver disease?

Non-alcoholic fatty liver disease (NAFLD) and irritable bowel syndrome (IBS) are two very common diseases in the general population. To date, there are no studies that highlight a direct link between NAFLD and IBS, but some recent reports have found an interesting correlation between obesity and IBS. A systematic PubMed database search was conducted highlighting that common mechanisms are involved in many of the local and systemic manifestations of NAFLD, leading to an increased cardiovascular risk, and IBS, leading to microbial dysbiosis, impaired intestinal barrier and altered intestinal motility. It is not known when considering local and systemic inflammation/immune system activation, which one has greater importance in NAFLD and IBS pathogenesis. Also, the nervous system is implicated. In fact, inflammation participates in the development of mood disorders, such as anxiety and depression, characteristics of obesity and consequently of NAFLD and, on the other hand, in intestinal hypersensitivity and dysmotility.

Small intestinal bacterial overgrowth and delayed orocecal transit time in patients with cirrhosis and low-grade hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is associated with poor prognosis in cirrhosis. Gut-derived nitrogenous substances play a role in pathogenesis of HE. The present study was conducted to assess small intestinal bacterial overgrowth (SIBO) and prolonged orocecal transit time (OCTT) in cirrhosis and low-grade HE.

METHODS

In cross-sectional prospective study, 75 patients were divided into 3 groups: group 1 (no HE, n = 31), group 2 (minimal HE, n = 29), and group 3 (early/grade 1 HE, n = 15). Minimal HE (MHE) was diagnosed when psychometric hepatic encephalopathy score (PHES) was ≤5. Early HE was diagnosed, according to West Haven criteria. All patients underwent glucose hydrogen breath test (GHBT) for SIBO and lactulose hydrogen breath test (LHBT) for OCTT.

RESULTS

A total of 29 patients (38.67 %) had MHE and 15 (20 %) had early HE. Prevalence of MHE in Child-Turcotte-Pugh (CTP) class A, B, and C was 33.3, 38.71, and 45 %, respectively, while SIBO was detected in 26 (34.67 %). Prevalence of SIBO was 12.5 % in CTP class A, 41.94 % in CTP class B, and 50 % in CTP class C. Five (16.13 %) patients in no HE group had SIBO as compared to 14 (48.28 %) in MHE group and 7 (46.67 %) in early HE group (p = 0.018). OCTT was 111.13 ± 13.95 min in patients with no HE as compared to 137.59 ± 14.80 min in patients with MHE and 150 ± 15.12 min in patients with early HE (p < 0.001). OCTT was significantly prolonged in patients with SIBO (145 ± 17.49 min) than in those without SIBO (120.71 ± 18.3 min) (p < 0.001).

CONCLUSION

SIBO and delayed OCTT are more common with MHE and early HE in patients with cirrhosis.

Adjuvant nutrition management of patients with liver failure, including transplant

This article reviews nutrition support in patients with liver disease, including those who are undergoing surgery or liver transplant. The topics covered include the multifactorial etiology of malnutrition, nutritional assessment, and nutritional therapy. Recommendations for use of both enteral and parenteral nutrition are given in patients with alcoholic hepatitis, cirrhosis, and acute liver failure and in patients undergoing surgery or liver transplant.