Gut-liver axis in cirrhosis: Are hemodynamic changes a missing link?

Deciphering the Language of Intestinal Microbiota Associated with Sepsis, Organ Failure, and Mortality in Patients with Alcohol-Related Acute-on-Chronic Liver Failure (ACLF): A Pioneer Study in Latin America

ACLF is a severe stage of liver cirrhosis, characterized by multiple organ failure, systemic inflammation, and high short-term mortality. The intestinal microbiota (IM) influences its pathophysiology; however, there are currently no studies in Latin American populations. Therefore, we analyzed IM and its relationships with sepsis, organ failure, and mortality. In parallel, we quantified serum lipopolysaccharides as a marker of bacterial translocation. Fecal samples from 33 patients and 20 healthy controls (HCs) were obtained. The IMs were characterized by 16S-rRNA amplicon sequencing, the metagenomic functional predictive profiles were analyzed by PICRUSt2, and LPS quantification was performed by ELISA. Patients with ACLF showed significant alterations in alpha and beta diversity compared to the HCs. A strong dominance index accurately predicted 28-day and 90-day mortalities. The IMs showed a polarization toward Proteobacteria associated with increased LPS. The LPS correlated with clinical severity, organ dysfunction, and higher pathogenic taxa. The Klebsiella/Faecalibacterium ratio showed good performance in identifying sepsis (AUROC = 0.83). Furthermore, Morganella, Proteus, and Klebsiella were enriched in patients with multiorgan failure. Lactobacillus, Escherichia/Shigella, Veillonella, and Ruminococcus gnavus exhibited potential in predicting 28- and 90-day mortalities. The IM alterations in ACLF may be useful as clinical biomarkers of poor prognosis, primarily for mortality and sepsis. These findings are representative of western Mexico.

Gut microbiota analysis in cirrhosis and non-cirrhotic portal hypertension suggests that portal hypertension can be main factor of cirrhosis-specific dysbiosis

Gut dysbiosis plays an important role in cirrhosis, but the mechanism of its development was not established. The aim of the study was to test the hypothesis that portal hypertension can be the main factor in the development of gut dysbiosis in cirrhosis. This cross-sectional study included 25 patients with chronic non-cirrhotic portal hypertension due to extrahepatic portal vein obstruction after portal vein thrombosis (PVT) (NCPVT group), 29 cirrhotic patients without PVT (CirNoPVT), 15 cirrhotic patients with chronic PVT (CPVT), and 22 healthy controls. The fecal microbiota was assessed using 16S rRNA gene sequencing. The CirNoPVT and CPVT groups had largely similar differences in gut microbiota composition from the control group. Patients with NCPVT, as well as patients with cirrhosis, had a higher abundance of Streptococcus, Escherichia, Enterococcus, Enterobacteriaceae, Enterococcaceae, Streptococcaceae, Bacilli, Gammaproteobacteria, Proteobacteria, and a lower abundance of Roseburia, Faecalibacterium, Methanobrevibacter, Ruminococcaceae, Methanobacteriaceae, Clostridia, Methanobacteria, and Euryarchaeota as they were compared with healthy individuals. Patients with NCPVT had a higher abundance of Bifidobacterium, Bifidobacteriaceae, Actinobacteria, and a lower abundance of Gemmiger and Catenibacterium compared to healthy individuals, which was not observed in the cirrhosis groups. The abundance of Porphyromonadaceae with the genus Parabacteroides was reduced in both groups with PVT, but not in CirNoPVT. There were no significant differences in gut microbiota beta-diversity among the CirNoPVT, CPVT and NCPVT groups. All these groups had significant differences in beta-diversity from the control group. Portal hypertension seems be the main factor in the development of gut dysbiosis in cirrhosis.

Hepatic encephalopathy treatment after transjugular intrahepatic portosystemic shunt: a new perspective on the gut microbiota

Transjugular intrahepatic portosystemic shunt (TIPS) placement alleviates portal hypertension symptoms. Hepatic encephalopathy (HE) is a common complication of TIPS, impacting patient quality of life and the healthcare burden. Post-TIPS HE is associated with portosystemic shunting, elevated blood ammonia levels, and inflammation. Increasing attention has been given to the liver and intestinal circulation in recent years. An imbalance in intestinal microecology plays a role in the occurrence of HE and may be a new target for treatment. This review discusses the causes, diagnosis, and treatment strategies for post-TIPS HE and focuses on exploring treatment strategies and their relationships with the gut microbiota, suggesting an innovative approach to address this complication.

Akkermansia muciniphila is associated with normal muscle mass and Eggerthella is related with sarcopenia in cirrhosis

BACKGROUND

Sarcopenia and gut dysbiosis are common in cirrhosis. The aim is to study the correlations between the gut microbiota taxa and muscle mass level in cirrhosis.

METHODS

The study included 40 cirrhosis patients including 18 patients with sarcopenia. The gut microbiota composition was assessed using amplicon sequencing of the hypervariable V3-V4 regions of the 16S rRNA gene. The skeletal muscle mass, subcutaneous and visceral fat levels were assessed with abdominal computed tomography as skeletal muscle, subcutaneous and visceral fat indices (SMI, SFI and VFI).

RESULTS

Patients with sarcopenia had more relative abundance (RA) of Agathobacter, Anaerostipes, Butyricicoccus, Dorea, Eggerthella, Microbacteriaceae, Veillonella and less RA of Akkermansiaceae, Akkermansia muciniphila, Verrucomicrobiae and Bilophila compared to patients with normal muscle mass. SMI directly correlated with RA of Akkermansia, Alistipes indistinctus, Anaerotruncus, Atopobiaceae, Bacteroides clarus, Bacteroides salyersiae, Barnesiellaceae, Bilophila wadsworthia, Pseudomonadota, Olsenella, and Parabacteroides distasonis, and negatively correlated with RA of Anaerostipes and Eggerthella. Sarcopenia was detected in 20.0% patients whose gut microbiota had Akkermansia but not Eggerthella, and in all the patients, whose gut microbiota had Eggerthella but not Akkermansia. The Akkermansia and Eggerthella abundances were independent determinants of SMI. RA of Akkermansia, Akkermansia muciniphila, Akkermansiaceae, Bacteroides salyersiae, Barnesiella, Bilophila, Desulfobacterota, Verrucomicrobiota and other taxa correlated positively and RA of Anaerovoracaceae, Elusimicrobiaceae, Elusimicrobium, Kiritimatiellae, Spirochaetota, and other taxa correlated negatively with the SFI. RA of Alistripes, Romboutsia, Succinivibrio, and Succinivibrionaceae correlated positively and RA of Bacteroides thetaiotaomicron correlated negatively with VFI.

CONCLUSION

The muscle mass level in cirrhosis correlates with the abundance of several gut microbiota taxa, of which Akkermansia and Eggerthella seems to be the most important.

Gut Microbiota and Cytokine Profile in Cirrhosis

BACKGROUND AND AIMS

Gut dysbiosis and abnormal cytokine profiles are common in cirrhosis. This study aimed to evaluate the correlations between them.

METHODS

In the blood plasma of cirrhosis patients and controls, 27 cytokines were examined using a multiplex assay. The plasma levels of nitrites (stable metabolites of the endothelial dysfunction biomarker nitric oxide) and lipopolysaccharide (LPS) were examined. The fecal microbiota was assessed by 16S rRNA gene sequencing.

RESULTS

Levels of IL-1b, IL-2, IL-6, IL-13, IP-10, IFN-g, TNF-a, LPS, and nitrites were higher in cirrhosis patients than in controls, while levels of IL-4, IL-7, and PDGF-BB were lower. The LPS level was directly correlated with the levels of IL-1b, IL1-Ra, IL-9, IL-17, PDGF-BB, IL-6, TNF-a, and nitrites. The nitrite level was significantly directly correlated with the levels of TNF-a, GM-CSF, IL-17, and IL-12, and inversely correlated with the IL-7 level. TNF-a levels were directly correlated with ascites severity and the abundance of Negativicutes, Enterobacteriaceae, Veillonellaceae, and Klebsiella, while inversely correlated with the abundance of Firmicutes, Clostridia, and Subdoligranulum. IFN-g levels were directly correlated with the abundance of Bacteroidaceae, Lactobacillaceae, Bacteroides, and Megasphaera, and inversely correlated with the abundance of Verrucomicrobiota, Akkermansiaceae, Coriobacteriaceae, Akkermansia, Collinsella, and Gemella. IL-1b levels were directly correlated with the abundance of Comamonadaceae and Enterobacteriaceae and inversely correlated with the abundance of Marinifilaceae and Dialister. IL-6 levels were directly correlated with the abundance of Enterobacteriaceae, hepatic encephalopathy, and ascites severity, and inversely correlated with the abundance of Peptostreptococcaceae, Streptococcaceae, and Streptococcus.

CONCLUSIONS

The abundance of harmful gut microbiota taxa and endotoxinemia directly correlates with the levels of proinflammatory cytokines.

Effect of Saccharomyces boulardii on Liver Diseases: A Systematic Review

We aimed to systematize the results of published studies on the use of Saccharomyces boulardii (SB) for the treatment of various liver disorders (CRD42022378050). Searches were conducted using PubMed and Scopus on 1 August 2022. The PubMed search was updated on 15 June 2024. The review included sixteen studies: ten experimental animal studies (EASs) and six randomized controlled trials (RCTs). The CNCM I-745 strain was used in 68.8% of the included studies. SB reduced the severity of many manifestations of cirrhosis, and lowered the Child-Pugh scores in RCT. SB reduced the serum concentrations of TNF-α, IL-1β, IL-6, and IL-4 in animals with metabolic dysfunction-associated steatotic liver disease (MASLD); lowered the serum TNF-α and IL-6 levels in experimental cirrhosis in rats; and reduced the CRP levels in decompensated cirrhosis. The EAS of MASLD revealed that SB reduced liver steatosis and inflammation and lowered the liver expression of genes of TNF-α, IL-1β, interferon-γ, and IL-10. In studies on experimental cirrhosis and MASLD, SB reduced the liver expression of genes of TGF-β, α-SMA, and collagen as well as liver fibrosis. SB reduced the abundance of Escherichia (Proteobacteria), increased the abundance of Bacteroidetes in the gut microbiota, prevented an increase in intestinal barrier permeability, and reduced bacterial translocation and endotoxemia.

Importance of the gut microbiota in the gut-liver axis in normal and liver disease

The gut microbiota is of growing interest to clinicians and researchers. This is because there is a growing understanding that the gut microbiota performs many different functions, including involvement in metabolic and immune processes that are systemic in nature. The liver, with its important role in detoxifying and metabolizing products from the gut, is at the forefront of interactions with the gut microbiota. Many details of these interactions are not yet known to clinicians and researchers, but there is growing evidence that normal gut microbiota function is important for liver health. At the same time, factors affecting the gut microbiota, including nutrition or medications, may also have an effect through the gut-liver axis.

Presepsin as a biomarker of bacterial translocation and an indicator for the prescription of probiotics in cirrhosis

BACKGROUND

The gut-liver axis and bacterial translocation are important in cirrhosis, but there is no available universal biomarker of cellular bacterial translocation, for which presepsin may be a candidate.

AIM

To evaluate the relationship of the blood presepsin levels with the state of the gut microbiota in cirrhosis in the absence of obvious infection.

METHODS

This study included 48 patients with Child-Pugh cirrhosis classes B and C and 15 healthy controls. The fecal microbiome was assessed using 16S rRNA gene sequencing. Plasma levels of presepsin were measured. A total of 22 patients received a probiotic (Saccharomyces boulardii) for 3 months.

RESULTS

Presepsin levels were higher in patients with cirrhosis than in healthy individuals [342 (91-2875) vs 120 (102-141) pg/mL; P = 0.048]. Patients with elevated presepsin levels accounted for 56.3% of all included patients. They had lower levels of serum albumin and higher levels of serum total bilirubin and overall severity of cirrhosis as assessed using the Child-Pugh scale. Patients with elevated presepsin levels had an increased abundance of the main taxa responsible for bacterial translocation, namely Bacilli and Proteobacteria (including the main class Gammaproteobacteria and the minor taxa Xanthobacteraceae and Stenotrophomonas), and a low abundance of bacteria from the family Lachnospiraceae (including the minor genus Fusicatenibacter), which produce short-chain fatty acids that have a positive effect on intestinal barrier function. The presepsin level directly correlated with the relative abundance of Bacilli, Proteobacteria, and inversely correlated with the abundance of Lachnospiraceae and Propionibacteriaceae. After 3 months of taking the probiotic, the severity of cirrhosis on the Child-Pugh scale decreased significantly only in the group with elevated presepsin levels [from 9 (8-11) to 7 (6-9); P = 0.004], while there were no significant changes in the group with normal presepsin levels [from 8 (7-8) to 7 (6-8); P = 0.123]. A high level of presepsin before the prescription of the probiotic was an independent predictor of a greater decrease in Child-Pugh scores (P = 0.046), as well as a higher level of the Child-Pugh scale (P = 0.042), but not the C-reactive protein level (P = 0.679) according to multivariate linear regression analysis.

CONCLUSION

The level of presepsin directly correlates with the abundance in the gut microbiota of the main taxa that are substrates of bacterial translocation in cirrhosis. This biomarker, in the absence of obvious infection, seems important for assessing the state of the gut-liver axis in cirrhosis and deciding on therapy targeted at the gut microbiota in this disease.

Gut Microbiota and Biomarkers of Intestinal Barrier Damage in Cirrhosis

Gut dysbiosis and subclinical intestinal damage are common in cirrhosis. The aim of this study was to examine the association of intestinal damage biomarkers (diamine oxidase [DAO], claudin 3, and intestinal fatty acid binding protein [I-FABP; FABP2]) with the state of the gut microbiota in cirrhosis. The blood levels of DAO were inversely correlated with blood levels of claudin 3, lipopolysaccharide (LPS), presepsin, TNF-α, and the severity of cirrhosis according to Child-Pugh scores. The blood level of I-FABP was directly correlated with the blood level of claudin 3 but not with that of DAO. Patients with small intestinal bacterial overgrowth (SIBO) had lower DAO levels than patients without SIBO. There was no significant difference in claudin 3 levels and I-FABP detection rates between patients with and without SIBO. The DAO level was directly correlated with the abundance of Akkermansiaceae, Akkermansia, Allisonella, Clostridiaceae, Dialister, Lactobacillus, Muribaculaceae, Negativibacillus, Ruminococcus, Thiomicrospiraceae, Verrucomicrobiae, and Verrucomicrobiota; and it was inversely correlated with the abundance of Anaerostipes, Erysipelatoclostridium, and Vibrio. The I-FABP level was directly correlated with Anaerostipes, Bacteroidia, Bacteroidota, Bilophila, Megamonas, and Selenomonadaceae; and it was inversely correlated with the abundance of Brucella, Pseudomonadaceae, Pseudomonas, and Vibrionaceae. The claudin 3 level was directly correlated with Anaerostipes abundance and was inversely correlated with the abundance of Brucella, Coriobacteriia, Eggerthellaceae, and Lactobacillus.

Gut Microbiota and Biomarkers of Endothelial Dysfunction in Cirrhosis

Our aim was to study the association of endothelial dysfunction biomarkers with cirrhosis manifestations, bacterial translocation, and gut microbiota taxa. The fecal microbiome was assessed using 16S rRNA gene sequencing. Plasma levels of nitrite, big endothelin-1, asymmetric dimethylarginine (ADMA), presepsin, and claudin were measured as biomarkers of endothelial dysfunction, bacterial translocation, and intestinal barrier dysfunction. An echocardiography with simultaneous determination of blood pressure and heart rate was performed to evaluate hemodynamic parameters. Presepsin, claudin 3, nitrite, and ADMA levels were higher in cirrhosis patients than in controls. Elevated nitrite levels were associated with high levels of presepsin and claudin 3, the development of hemodynamic circulation, hypoalbuminemia, grade 2-3 ascites, overt hepatic encephalopathy, high mean pulmonary artery pressure, increased abundance of Proteobacteria and Erysipelatoclostridium, and decreased abundance of Oscillospiraceae, Subdoligranulum, Rikenellaceae, Acidaminococcaceae, Christensenellaceae, and Anaerovoracaceae. Elevated ADMA levels were associated with higher Child-Pugh scores, lower serum sodium levels, hypoalbuminemia, grade 2-3 ascites, milder esophageal varices, overt hepatic encephalopathy, lower mean pulmonary artery pressure, and low abundance of Erysipelotrichia and Erysipelatoclostridiaceae. High big endothelin-1 levels were associated with high levels of presepsin and sodium, low levels of fibrinogen and cholesterol, hypocoagulation, increased Bilophila and Coprobacillus abundances, and decreased Alloprevotella abundance.

Efficacy and Safety of a Probiotic Containing Saccharomyces boulardii CNCM I-745 in the Treatment of Small Intestinal Bacterial Overgrowth in Decompensated Cirrhosis: Randomized, Placebo-Controlled Study

(1) Background: The aim was to evaluate the effectiveness of the probiotic containing Saccharomyces boulardii in the treatment of small intestinal bacterial overgrowth (SIBO) in patients with decompensated cirrhosis. (2) Methods: This was a blinded, randomized, placebo-controlled study. (3) Results: After 3 months of treatment, SIBO was absent in 80.0% of patients in the probiotic group and in 23.1% of patients in the placebo group (p = 0.002). The patients with eliminated SIBO had decreased frequency of ascites and hepatic encephalopathy, the increased platelets and albumin levels, the decreased blood levels of total bilirubin, biomarkers of bacterial translocation (lipopolysaccharide [LPS]) and systemic inflammation (C-reactive protein), and positive changes in markers of hyperdynamic circulation compared with the state at inclusion. There were no significant changes in the claudin 3 level (the intestinal barrier biomarker) in these patients. No significant changes were observed in the group of patients with persistent SIBO. The serum level of nitrate (endothelial dysfunction biomarker) was lower in patients with eradicated SIBO than in patients with persistent SIBO. One (5.3%) patient with eradicated SIBO and six (42.9%) patients with persistent SIBO died within the first year of follow-up (p = 0.007). (4) Conclusions: SIBO eradication was an independent predictor of a favorable prognosis during the first year of follow-up.

Frailty in end-stage liver disease: Understanding pathophysiology, tools for assessment, and strategies for management

Frailty and sarcopenia are frequently observed in patients with end-stage liver disease. Frailty is a complex condition that arises from deteriorations across various physiological systems, including the musculoskeletal, cardiovascular, and immune systems, resulting in a reduced ability of the body to withstand stressors. This condition is associated with declined resilience and increased vulnerability to negative outcomes, including disability, hospitalization, and mortality. In cirrhotic patients, frailty is influenced by multiple factors, such as hyperammonemia, hormonal imbalance, malnutrition, ascites, hepatic encephalopathy, and alcohol intake. Assessing frailty is crucial in predicting morbidity and mortality in cirrhotic patients. It can aid in making critical decisions regarding patients' eligibility for critical care and transplantation. This, in turn, can guide the development of an individualized treatment plan for each patient with cirrhosis, with a focus on prioritizing exercise, proper nutrition, and appropriate treatment of hepatic complications as the primary lines of treatment. In this review, we aim to explore the topic of frailty in liver diseases, with a particular emphasis on pathophysiology, clinical assessment, and discuss strategies for preventing frailty through effective treatment of hepatic complications. Furthermore, we explore novel assessment and management strategies that have emerged in recent years, including the use of wearable technology and telemedicine.

Gut Microbiota and Bacterial Translocation in the Pathogenesis of Liver Fibrosis

Cirrhosis is the end result of liver fibrosis in chronic liver diseases. Studying the mechanisms of its development and developing measures to slow down and regress it based on this knowledge seem to be important tasks for medicine. Currently, disorders of the gut-liver axis have great importance in the pathogenesis of cirrhosis. However, gut dysbiosis, which manifests as increased proportions in the gut microbiota of Bacilli and Proteobacteria that are capable of bacterial translocation and a decreased proportion of Clostridia that strengthen the intestinal barrier, occurs even at the pre-cirrhotic stage of chronic liver disease. This leads to the development of bacterial translocation, a process by which those microbes enter the blood of the portal vein and then the liver tissue, where they activate Kupffer cells through Toll-like receptor 4. In response, the Kupffer cells produce profibrogenic cytokines, which activate hepatic stellate cells, stimulating their transformation into myofibroblasts that produce collagen and other elements of the extracellular matrix. Blocking bacterial translocation with antibiotics, probiotics, synbiotics, and other methods could slow down the progression of liver fibrosis. This was shown in a number of animal models but requires further verification in long-term randomized controlled trials with humans.

The Gut-Organ Axis within the Human Body: Gut Dysbiosis and the Role of Prebiotics

The human gut microbiota (GM) is a complex microbial ecosystem that colonises the gastrointestinal tract (GIT) and is comprised of bacteria, viruses, fungi, and protozoa. The GM has a symbiotic relationship with its host that is fundamental for body homeostasis. The GM is not limited to the scope of the GIT, but there are bidirectional interactions between the GM and other organs, highlighting the concept of the "gut-organ axis". Any deviation from the normal composition of the GM, termed "microbial dysbiosis", is implicated in the pathogenesis of various diseases. Only a few studies have demonstrated a relationship between GM modifications and disease phenotypes, and it is still unknown whether an altered GM contributes to a disease or simply reflects its status. Restoration of the GM with probiotics and prebiotics has been postulated, but evidence for the effects of prebiotics is limited. Prebiotics are substrates that are "selectively utilized by host microorganisms, conferring a health benefit". This study highlights the bidirectional relationship between the gut and vital human organs and demonstrates the relationship between GM dysbiosis and the emergence of certain representative diseases. Finally, this article focuses on the potential of prebiotics as a target therapy to manipulate the GM and presents the gaps in the literature and research.

Gut Dysbiosis and Hemodynamic Changes as Links of the Pathogenesis of Complications of Cirrhosis

The aim was to evaluate the relationship between gut dysbiosis and hemodynamic changes (hyperdynamic circulation) in cirrhosis, and between hemodynamic changes and complications of this disease. This study included 47 patients with cirrhosis. Stool microbiome was assessed using 16S rRNA gene sequencing. Echocardiography with a simultaneous assessment of blood pressure and heart rate was performed to assess systemic hemodynamics. Patients with hyperdynamic circulation had more severe cirrhosis, lower albumin, sodium and prothrombin levels, higher C-reactive protein, aspartate aminotransferase and total bilirubin levels, and higher incidences of portopulmonary hypertension, ascites, overt hepatic encephalopathy, hypoalbuminemia, hypoprothrombinemia, systemic inflammation, and severe hyperbilirubinemia than patients with normodynamic circulation. Patients with hyperdynamic circulation compared with those with normodynamic circulation had increased abundance of Proteobacteria, Enterobacteriaceae, Bacilli, Streptococcaceae, Lactobacillaceae, Fusobacteria, Micrococcaceae, Intestinobacter, Clostridium sensu stricto, Proteus and Rumicoccus, and decreased abundance of Bacteroidetes, Bacteroidaceae, Holdemanella, and Butyrivibrio. The systemic vascular resistance and cardiac output values correlated with the abundance of Proteobacteria, Enterobacteriaceae, Bacilli, Streptococcaceae, Lactobacillaceae, Micrococcaceae, and Fusobacteria. Heart rate and cardiac output value were negatively correlated with the abundance of Bacteroidetes. The mean pulmonary artery pressure value was positively correlated with the abundance of Proteobacteria and Micrococcaceae, and negatively with the abundance of Holdemanella.

Sarcopenia in cirrhosis: Prospects for therapy targeted to gut microbiota

Decreased muscle mass and function, also known as sarcopenia, is common in patients with cirrhosis and is associated with a poor prognosis. Although the pathogenesis of this disorder has not been fully elucidated, a disordered gut-muscle axis probably plays an important role. Decreased barrier function of the gut and liver, gut dysbiosis, and small intestinal bacterial overgrowth (SIBO) can lead to increased blood levels of ammonia, lipopolysaccharides, pro-inflammatory mediators, and myostatin. These factors have complex negative effects on muscle mass and function. Drug interventions that target the gut microbiota (long-term use of rifaximin, lactulose, lactitol, or probiotics) positively affect most links of the compromised gut-muscle axis in patients with cirrhosis by decreasing the levels of hyperammonemia, bacterial translocation, and systemic inflammation and correcting gut dysbiosis and SIBO. However, although these drugs are promising, they have not yet been investigated in randomized controlled trials specifically for the treatment and prevention of sarcopenia in patients with cirrhosis. No data exist on the effects of fecal transplantation on most links of gut-muscle axis in cirrhosis; however, the results of animal experimental studies are promising.

Gut Microbiota and Neuroinflammation in Acute Liver Failure and Chronic Liver Disease

Acute liver failure and chronic liver disease are associated with a wide spectrum of neurological changes, of which the best known is hepatic encephalopathy (HE). Historically, hyperammonemia, causing astrocyte swelling and cerebral oedema, was considered the main etiological factor in the pathogenesis of cerebral dysfunction in patients with acute and/or chronic liver disease. However, recent studies demonstrated a key role of neuroinflammation in the development of neurological complications in this setting. Neuroinflammation is characterized by activation of microglial cells and brain secretion of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, which alter neurotransmission, leading to cognitive and motor dysfunction. Changes in the gut microbiota resulting from liver disease play a crucial role in the pathogenesis of neuroinflammation. Dysbiosis and altered intestinal permeability, resulting in bacterial translocation and endotoxemia, are responsible for systemic inflammation, which can spread to brain tissue and trigger neuroinflammation. In addition, metabolites derived from the gut microbiota can act on the central nervous system and facilitate the development of neurological complications, exacerbating clinical manifestations. Thus, strategies aimed at modulating the gut microbiota may be effective therapeutic weapons. In this review, we summarize the current knowledge on the role of the gut-liver-brain axis in the pathogenesis of neurological dysfunction associated with liver disease, with a particular focus on neuroinflammation. In addition, we highlight emerging therapeutic approaches targeting the gut microbiota and inflammation in this clinical setting.

Epidemiology of small intestinal bacterial overgrowth

Small intestinal bacterial overgrowth (SIBO) is defined as an increase in the bacterial content of the small intestine above normal values. The presence of SIBO is detected in 33.8% of patients with gastroenterological complaints who underwent a breath test, and is significantly associated with smoking, bloating, abdominal pain, and anemia. Proton pump inhibitor therapy is a significant risk factor for SIBO. The risk of SIBO increases with age and does not depend on gender or race. SIBO complicates the course of a number of diseases and may be of pathogenetic significance in the development of their symptoms. SIBO is significantly associated with functional dyspepsia, irritable bowel syndrome, functional abdominal bloating, functional constipation, functional diarrhea, short bowel syndrome, chronic intestinal pseudo-obstruction, lactase deficiency, diverticular and celiac diseases, ulcerative colitis, Crohn's disease, cirrhosis, metabolic-associated fatty liver disease (MAFLD), primary biliary cholangitis, gastroparesis, pancreatitis, cystic fibrosis, gallstone disease, diabetes, hypothyroidism, hyperlipidemia, acromegaly, multiple sclerosis, autism, Parkinson's disease, systemic sclerosis, spondylarthropathy, fibromyalgia, asthma, heart failure, and other diseases. The development of SIBO is often associated with a slowdown in orocecal transit time that decreases the normal clearance of bacteria from the small intestine. The slowdown of this transit may be due to motor dysfunction of the intestine in diseases of the gut, autonomic diabetic polyneuropathy, and portal hypertension, or a decrease in the motor-stimulating influence of thyroid hormones. In a number of diseases, including cirrhosis, MAFLD, diabetes, and pancreatitis, an association was found between disease severity and the presence of SIBO. Further work on the effect of SIBO eradication on the condition and prognosis of patients with various diseases is required.

Therapeutic possibilities of gut microbiota modulation in acute decompensation of liver cirrhosis

The formation of liver cirrhosis (LC) is an unfavorable event in the natural history of chronic liver diseases and with the development of portal hypertension and/or impaired liver function can cause a fatal outcome. Decompensation of LC is considered the most important stratification variable for the risk of death. It is currently postulated that decompensation of LC occurs through an acute (including acute-on-chronic liver failure) and non-acute pathway. Acute decompensation of LC is accompanied by the development of life-threatening complications, characterized by an unfavorable prognosis and high mortality. Progress in understanding the underlying molecular mechanisms has led to the search for new interventions, drugs, and biological substances that can affect key links in the pathogenesis of acute decompensation in LC, for example the impaired gut-liver axis and associated systemic inflammation. Given that particular alterations in the composition and function of gut microbiota play a crucial role here, the study of the therapeutic possibilities of its modulation has emerged as one of the top concerns in modern hepatology. This review summarized the investigations that describe the theoretical foundations and therapeutic potential of gut microbiota modulation in acute decompensation of LC. Despite the encouraging preliminary data, the majority of the suggested strategies have only been tested in animal models or in preliminary clinical trials; additional multicenter randomized controlled trials must demonstrate their efficacy in larger patient populations.

Fecal microbiota transplantation in non-communicable diseases: Recent advances and protocols

Fecal microbiota transplant (FMT) is a therapeutic method that aims to restore normal gut microbial composition in recipients. Currently, FMT is approved in the USA to treat recurrent and refractory Clostridioides difficile infection and has been shown to have great efficacy. As such, significant research has been directed toward understanding the potential role of FMT in other conditions associated with gut microbiota dysbiosis such as obesity, type 2 diabetes mellitus, metabolic syndrome, neuropsychiatric disorders, inflammatory bowel disease, irritable bowel syndrome, decompensated cirrhosis, cancers and graft-versus-host disease. This review examines current updates and efficacy of FMT in treating conditions other than Clostridioides difficile infection. Further, protocols for administration of FMT are also discussed including storage of fecal samples in stool banks, inclusion/exclusion criteria for donors, fecal sample preparation and methods of treatment administration. Overall, understanding the mechanisms by which FMT can manipulate gut microbiota to provide therapeutic benefit as well as identifying potential adverse effects is an important step in clarifying its long-term safety and efficacy in treating multiple conditions in the future.

Effect of probiotics on hemodynamic changes and complications associated with cirrhosis: A pilot randomized controlled trial

BACKGROUND

Bacterial translocation exacerbates the hyperdynamic circulation observed in cirrhosis and contributes to a more severe disease course. Probiotics may reduce bacterial translocation and may therefore be useful to redress the circulatory imbalance.

AIM

To investigate the effect of probiotics on hemodynamic parameters, systemic inflammation, and complications of cirrhosis in this randomized placebo-controlled trial.

METHODS

This single-blind randomized placebo-controlled study included 40 patients with Child-Pugh class B and C cirrhosis; 24 patients received probiotics (Saccharomyces boulardii) for 3 mo, and 16 patients received a placebo over the same period. Liver function and the systemic hemodynamic status were evaluated pre- and post-intervention. Echocardiography and simultaneous blood pressure and heart rate monitoring were performed to evaluate systemic hemodynamic indicators. Cardiac output and systemic vascular resistance were calculated.

RESULTS

Following a 3-mo course of probiotics in comparison to the control group, we observed amelioration of hyperdynamic circulation [a decrease in cardiac output (P = 0.026) and an increase in systemic vascular resistance (P = 0.026)] and systemic inflammation [a decrease in serum C-reactive protein levels (P = 0.044)], with improved liver function [an increase in serum albumin (P = 0.001) and a decrease in the value of Child-Pugh score (P = 0.001)] as well as a reduction in the severity of ascites (P = 0.022), hepatic encephalopathy (P = 0.048), and cholestasis [a decrease in serum alkaline phosphatase (P = 0.016) and serum gamma-glutamyl transpeptidase (P = 0.039) activity] and an increase in platelet counts (P < 0.001) and serum sodium level (P = 0.048).

CONCLUSION

Probiotic administration was associated with amelioration of hyperdynamic circulation and the associated complications of cirrhosis.

Influence of Gut–Liver Axis on Portal Hypertension in Advanced Chronic Liver Disease: The Gut Microbiome as a New Protagonist in Therapeutic Management

Clinically significant portal hypertension is associated with most complications of advanced chronic liver disease (ACLD), including variceal bleeding, ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, and hepatic encephalopathy. Gut dysbiosis is a hallmark of ACLD with portal hypertension and consists of the overgrowth of potentially pathogenic bacteria and a decrease in autochthonous bacteria; additionally, congestion makes the intestinal barrier more permeable to bacteria and their products, which contributes to the development of complications through inflammatory mechanisms. This review summarizes current knowledge on the role of the gut–liver axis in the pathogenesis of portal hypertension, with a focus on therapies targeting portal hypertension and the gut microbiota. The modulation of the gut microbiota on several levels represents a major challenge in the upcoming years; in-depth characterization of the molecular and microbiological mechanisms linking the gut–liver axis to portal hypertension in a bidirectional relationship could pave the way to the identification of new therapeutic targets for innovative therapies in the management of ACLD.

Effects of Probiotic Supplementation during Pregnancy on the Future Maternal Risk of Metabolic Syndrome

Probiotics are live microorganisms that induce health benefits in the host. Taking probiotics is generally safe and well tolerated by pregnant women and their children. Consumption of probiotics can result in both prophylactic and therapeutic effects. In healthy adult humans, the gut microbiome is stable at the level of the dominant taxa: Bacteroidetes, Firmicutes and Actinobacteria, and has a higher presence of Verrucomicrobia. During pregnancy, an increase in the number of Proteobacteria and Actinobacteria phyla and a decrease in the beneficial species Roseburia intestinalis and Faecalibacterium prausnitzii are observed. Pregnancy is a "window" to the mother's future health. The aim of this paper is to review studies assessing the potentially beneficial effects of probiotics in preventing the development of diseases that appear during pregnancy, which are currently considered as risk factors for the development of metabolic syndrome, and consequently, reducing the risk of developing maternal metabolic syndrome in the future. The use of probiotics in gestational diabetes mellitus, preeclampsia and excessive gestational weight gain is reviewed. Probiotics are a relatively new intervention that can prevent the development of these disorders during pregnancy, and thus, would reduce the risk of metabolic syndrome resulting from these disorders in the mother's future.

Влияние курсового приема L-орнитин- L-аспартата на фиброз и стеатоз печени у больных ассоциированной с нарушениями метаболизма жировой болезнью печени (неалкогольной жировой болезнью печени), имеющих гипераммониемию

Introduction.Hyperammonaemia develops both in cirrhosis and earlier fibrotic stages during metabolic-associated fatty liver disease (MAFLD). Besides neurotropic, ammonia exerts the hepatotoxic and profibrotic effects. L-ornithine-L-aspartate (LOLA) has been proved effective in treatment for hyperammonaemia in cirrhosis patients.Aim.An impact study of the LOLA course therapy on inflammation, steatosis and liver fibrosis biomarkers in MAFLD.Materials and methods.A total of 90 patients were divided between two cohorts. The control cohort included patients with liver steatosis S0–S1, absent liver fibrosis, normal liver function tests, clean history of liver disease, while MAFLD cohort gathered liver steatosis S2–S3 and METAVIR fibrosis F1. Steatosis and fibrosis were assessed with a Fibroscan 502 unit with CAP measurement. All patients had ammonia estimated from whole blood. At high ammonia, LOLA was ordered at 9 g/day for 8 weeks, with control of blood ammonia, AST, ALT, GGT, CRP and ferritin, as well as fibrosis and steatosis post-therapy.Results.The study enrolled 45 patients of the MAFLD and 45 — of control cohort. Hyperammonaemia was revealed in 26 (58 %) MAFLD and 3 (7 %) control patients (p <0.001). MAFLD-hyperammonaemic patients also had the significantly higher male ratio, type 2 diabetes and severer hepatic steatosis rates vs. hyperammonaemia-negative MAFLD individuals. In 8 weeks of LOLA therapy, the ALT, AST, GGT, ferritin and CRP levels decreased significantly, and blood ammonia attained normal range (p <0.001). Elastometry liver stiffness decreased in 22 (85 %) patients, reaching F0 values in 6 cases (p <0.001). The steatosis grade reduced in 18 (69 %) individuals.Conclusion.LOLA normalises blood ammonia levels and reduces the severity of inflammation, steatosis and liver fibrosis.