Gut Microbiota and Liver Regeneration: A Synthesis of Evidence on Structural Changes and Physiological Mechanisms

Liver regeneration (LR) is a unique biological process with the ability to restore up to 70% of the organ. This allows for the preservation of liver resections for various liver tumors and for living donor liver transplantation (LDLT). However, in some cases, LR is insufficient and interventions that can improve LR are urgently needed. Gut microbiota (GM) is one of the factors influencing LR, as the liver and intestine are intimately connected through the gut-liver axis. Thus, healthy GM facilitates normal LR, whereas dysbiosis leads to impaired LR due to imbalance of bile acids, inflammatory cytokines, microbial metabolites, signaling pathways, etc. Therefore, GM can be considered as a new possible therapeutic target to improve LR. In this review, we critically observe the current knowledge about the influence of gut microbiota (GM) on liver regeneration (LR) and the possibility to improve this process, which may reduce complication and mortality rates after liver surgery. Although much research has been done on this topic, more clinical trials and systemic reviews are urgently needed to move this type of intervention from the experimental phase to the clinical field.

Applied physiology: gut microbiota and antimicrobial therapy

The gut microbiota plays an important role in maintaining human health and in the pathogenesis of several diseases. Antibiotics are among the most commonly prescribed drugs and have a significant impact on the structure and function of the gut microbiota. The understanding that a healthy gut microbiota prevents the development of many diseases has also led to its consideration as a potential therapeutic target. At the same time, any factor that alters the gut microbiota becomes important in this approach. Exercise and antibacterial therapy have a direct effect on the microbiota. The review reflects the current state of publications on the mechanisms of intestinal bacterial involvement in the pathogenesis of cardiovascular, metabolic, and neurodegenerative diseases. The physiological mechanisms of the influence of physical activity on the composition of the gut microbiota are considered. The mechanisms of the common interface between exercise and antibacterial therapy will be considered using the example of several socially important diseases. The aim of the study is to show the physiological relationship between the effects of exercise and antibiotics on the gut microbiota.

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.

Small Intestinal Bacterial Overgrowth in Various Specialties of Medical Practice (Literature Review and Expert Council Resolution)

Aim: to discuss current views on the clinical significance, diagnostic opportunities, and therapeutic approaches in the treatment of small intestinal bacterial overgrowth (SIBO) as an important component in the gut microbiota function assessment, to assess the awareness of physicians and the opportunities in the diagnosis and treatment of this disease in patients in the Federal districts of the Russian Federation, as well as to present the proceedings of the Expert Council held on December 16, 2023 in Moscow.

Key points. SIBO is a common syndrome often associated with irritable bowel syndrome, liver cirrhosis, asthma, and congestive heart failure, being also a predictor of early death in the elderly. Today, in many regions of the Russian Federation, there are limitations for instrumental diagnosis of this disease — lack of awareness among doctors, unavailability of gas analyzers for diagnosing SIBO, lack of information about the need to diagnose SIBO in the standards of compulsory health insurance. Rifaximin is the first-line treatment due to the highest therapeutic efficacy. One of the ways to increase the efficacy of SIBO treatment is to include strain-specific probiotics in the treatment regimen. Saccharomyces boulardii CNCM I-745 is thought to be the most studied, promising probiotic. The review also presents statistical data on the issues in the diagnosis and treatment of SIBO in the regions of the Russian Federation.

Conclusion. Optimization of approaches to the diagnosis and treatment of SIBO, the development of domestic gas analyzers, increasing the awareness of physicians in all regions of the Russian Federation, as well as the development and optimization of clinical recommendations appear to be necessary measures to increase the effectiveness of medical care, the duration and quality of life of the Russian population. These goals can be achieved within the framework of Federal programs under the supervision of specialized reference centers of the Ministry of Health of the Russian Federation.

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.

Impact of Novel Coronavirus Infection on the Course and Prognosis of Cirrhosis

Аim: to investigate the impact of COVID-19 on the course and prognosis of cirrhosis.

Materials and methods. This was a cohort study in patients with cirrhosis. We included patients with cirrhosis who underwent a medical examination at our center between September 2019 and March 2020. We determined which of these patients were infected with COVID-19, died of COVID-19, or died of cirrhosis complications within the follow-up period from April 2020 to September 2021. Thereafter, we conducted a second medical examination of these surviving patients with cirrhosis in September to December 2021.

Results. Among the 226 patients included in the study, 57 had COVID-19, among which 19 patients who died of the disease. Acute-on-chronic liver failure (ACLF) developed in 16 (28.1 %) patients with cirrhosis and COVID-19, 13 (81.3 %) of whom died. One of the COVID-19 survivors eventually died of liver decompensation. Twenty patients who did not have COVID-19 died of complications of cirrhosis (ACLF) during the follow-up period. The mortality rate in patients who were infected with COVID-19 was higher than that in patients who were not infected (35.1 % vs. 14.2 %; p = 0.001). COVID-19 was an independent risk factor for death in patients with cirrhosis. No liver-specific factors predisposing to COVID-19 infection were identified. A more impaired liver function in the pre-pandemic medical examination was a predisposing factor for death in patients who had COVID-19. Patients who died of COVID-19 had better liver function in the pre-pandemic medical examination than patients without COVID-19 who died of complications of cirrhosis during the follow-up period. The liver-related mortality rate and the incidence of liver decompensation or bleeding from esophageal varices during the follow-up period were not significantly different between patients who recovered from COVID-19 and patients with cirrhosis who did not have COVID-19. Among the analyzed survivors, no significant changes were found in the main indicators of liver function after the follow-up period between patients with and without COVID-19, except for the prothrombin index, which was higher in patients after COVID-19.

Conclusion. COVID-19 worsens the prognosis of patients with cirrhosis but does not substantially affect the course of cirrhosis after the recovery from this infection.

Sarilumab is not Inferior to Tocilizumab in the Treatment of Cytokine Release Syndrome in COVID-19

Objective. Cytokine release syndrome (CRS) is a dangerous complication of the new coronavirus infection (COVID-19). The study aimed to compare sarilumab (SAR group) with tocilizumab (TOC group) and patients without anticytokine treatment (CON group) in treatment of CRS in COVID-19.

Methods. The retrospective real life study included COVID-19 patients with C-reactive protein(CRP)  level >60 mg/l.

Results. We enrolled 24 patients in SAR group, 27 patients in TOC group and 47 patients in CON group. Mortality was lower in SAR and TOC groups than in CON group (12.5% and 14.8% vs. 31.9%; p=0.021 and p=0.031) with no difference between SAR and TOC groups (p=0.389).  SAR patients unlike TOC patients required intensive care unit admission less frequently then CON patients (16.7% and 25.9% vs. 46.3%; p=0.013 and p=0.077). An increase in oxygen saturation was observed in SAR and TOC groups (p=0.001 and p=0.004; greater in SAR group [p=0.022]), but not in CON group (p=0.764) in 7-10 days after administration of these drugs. The decrease in CRP level was greater in  SAR and TOC groups than in CON group (p=0.016 and p<0.011), with no difference between SAR and TOC groups (p=0.236).

Conclusion. Sarilumab is not inferior to tocilizumab in COVID-19

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.

Intestinal Barrier and Gut Microbiota in Patients with Overlapping Irritable Bowel Syndrome and Functional Dyspepsia

BACKGROUND

Disturbances in the intestinal barrier and gut dysbiosis have been observed in patients with functional bowel diseases.

AIMS

To investigate the correlation between biomarkers of intestinal barrier disorders at different layers and the severity of symptoms in patients with overlapping diarrhea-predominant irritable bowel syndrome and functional dyspepsia (IDFO), as well as with gut microbiota taxa.

METHODS

This study included 45 patients with IDFO and 16 healthy controls. Endoscopy with biopsy of the duodenum and sigmoid colon (SC) was performed to count intraepithelial lymphocytes (IELs) and mucosal eosinophils (subepithelial layer), assess fatty acid binding protein (FABP; epithelial layer) level, and stain for mucin-2 (MUC-2; pre-epithelial layer). Composition of the gut microbiota was evaluated using 16S rRNA gene sequencing.

RESULTS

Patients with IDFO exhibited an increase in biomarkers of intestinal barrier disorders at all layers studied. IEL count in the duodenum was correlated with the severity of bloating (r = 0.336; p = 0.024) and, in the SC, was correlated with tenesmus severity (r = 0.303; p = 0.042). FABP-1 level in the SC was correlated with the severity of diarrhea (r = 0.577; p = 0.001), and FABP-5 concentration in the SC was correlated with abdominal distension (r = 0.477; p = 0.010). MUC-2 concentration in the duodenum was correlated with the severity of heartburn (r = 0.572; p = 0.025) and burning sensation in the epigastrium (r = 0.518; p = 0.048). All biomarkers of intestinal barrier permeability were correlated with the abundance of some gut microbiota taxa.

CONCLUSION

Patients with IDFO exhibited disrupted intestinal barrier function in all layers, which was associated with clinical symptom severity and changes in the gut microbiota.

Low Short-Chain-Fatty-Acid-Producing Activity of the Gut Microbiota Is Associated with Hypercholesterolemia and Liver Fibrosis in Patients with Metabolic-Associated (Non-Alcoholic) Fatty Liver Disease

The aim of this study was to investigate the short-chain fatty acid (SCFA) activity of the gut microbiota of patients with metabolic-associated fatty liver disease (MAFLD). The level and spectrum of short-chain fatty acids (SCFAs) were determined via gas–liquid chromatography. Liver fibrosis was assessed using the FIB-4 index and elastography. Among 42 non-cirrhotic MAFLD patients, 24 had high fecal SCFA levels (group H) and 18 had low fecal SCFA levels (group L). Patients in group H had lower serum uric acid, total cholesterol, and LDL cholesterol levels but a higher BMI than those in group L. All patients in group L and only 37.9% of those in group H were found to have hypercholesterolemia. In patients with hypercholesterolemia, the level of SCFAs was lower than that in patients without hypercholesterolemia. Patients in group H had less liver fibrosis than patients in group L. A total of 50.0% of the patients in group H and 92.3% of those in group L had significant liver fibrosis (≥F2). Patients with significant liver fibrosis had lower levels of fecal SCFAs—particularly acetate and butyrate. The fecal SCFA levels were positively correlated with gamma-glutamyl transferase, total bilirubin levels, BMI, and platelet count and were negatively correlated with FIB-4, liver stiffness, serum total, and LDL cholesterol levels.

Effect of Rebamipide on the Intestinal Barrier, Gut Microbiota Structure and Function, and Symptom Severity Associated with Irritable Bowel Syndrome and Functional Dyspepsia Overlap: A Randomized Controlled Trial

Treatment of functional digestive disorders is not always effective. Therefore, a search for new application points for potential drugs is perspective. Our aim is to evaluate the effect of rebamipide on symptom severity, intestinal barrier status, and intestinal microbiota composition and function in patients with diarrheal variant of irritable bowel syndrome overlapping with functional dyspepsia (D-IBSoFD). Sixty patients were randomized to receive trimebutine (TRI group), trimebutine + rebamipide (T + R group), or rebamipide (REB group) for 2 months. At the beginning and end of the study, patients were assessed for general health (SF-36), severity of digestive symptoms (Gastrointestinal Symptom Rating and 7 × 7 scales), state of the intestinal barrier, and composition (16S rRNA gene sequencing) and function (short-chain fatty acid fecal content) of the gut microbiota. The severity of most digestive symptoms was reduced in the REB and T + R groups to levels similar to that observed in the TRI group. The duodenal and sigmoidal lymphocytic and sigmoidal eosinophilic infiltration was decreased only in the REB and T + R groups, not in the TRI group. Serum zonulin levels were significantly decreased only in the REB group. A decrease in intraepithelial lymphocytic infiltration in the duodenum correlated with a decrease in the severity of rumbling and flatulence, while a decrease in infiltration within the sigmoid colon correlated with improved stool consistency and decreased severity of the sensation of incomplete bowel emptying. In conclusion, rebamipide improves the intestinal barrier condition and symptoms in D-IBSoFD. The rebamipide effects are not inferior to those of trimebutine.

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.

Clinical Practice Guidelines of the Scientific Society for the Clinical Study of Human Microbiome, of the Russian Gastroenterological Association and the Russian Society for the Prevention of Noncommunicable Diseases on the Diagnosis and Treatment of <i>Clostridioides difficile</i> (<i>C. difficile</i>)-associated Disease in Adults

Аim: the clinical practice guidelines intended for gastroenterologists, internal medicine specialists, infectious disease specialists, general practitioners (family doctors), coloproctologists, surgeons and endoscopists present modern methods of diagnosis, prevention and treatment of C. difficile-associated disease.

Key points. C. difficile-associated disease is a disease that develops when the diversity of the intestinal microbiota decreases and C. difficile excessively colonizes the colon, the toxins of which damage the intestinal muco-epithelial barrier, followed by the development of inflammation in the colon wall, with diarrhea being a characteristic clinical manifestation. The clinical presentation of the disease can vary from asymptomatic carriage, mild to moderate diarrhea that resolves on its own, to profuse watery diarrhea and pseudomembranous colitis with development of life-threatening complications. The diagnosis of C. difficile-associated disease is based on an assessment of the clinical presentation, medical history, an objective examination of the patient and laboratory stool tests. The disease severity is determined by clinical symptoms and laboratory findings. Additional diagnostic methods that are used according to indications and contribute to the assessment of severity include endoscopy of the colon and abdominal cavity imaging methods. Treatment should be initiated in cases of characteristic clinical presentation of C. difficile-associated disease and positive laboratory stool testing. The choice of drug and treatment regimen depends on the severity of the episode, the presence of complications, and whether the episode is initial, recurrent, or reinfection.

Conclusion. Determination of target groups of patients for the diagnosis of clostridial infection is important in preventing overdiagnosis and subsequent unnecessary treatment. Timely diagnosis and treatment of C. difficile-associated disease help avoiding the development of life-threatening complications and improve the prognosis and quality of life of patients.

Structure and Metabolic Activity of the Gut Microbiota in Diarrhea-Predominant Irritable Bowel Syndrome Combined with Functional Dyspepsia

Gut dysbiosis presents in many digestive diseases. The aim of this study is to investigate the composition of the gut microbiota and its metabolic activity in patients with diarrhea-predominant irritable bowel syndrome combined with functional dyspepsia (I + D). This study included 60 patients with I + D and 20 healthy controls. Gut microbiota composition was studied using 16S rRNA gene sequencing. The short-chain fatty acids (SCFAs) spectrum was determined via gas–liquid chromatography. Patients with I + D had an increase in the abundance of Holdemanella, Erysipelotrichaceae, Erysipelotrichales, Prevotellaceae, Agathobacter, Slackia, Lactococcus, Pseudomonadaceae, Stenotrophomonas, Xanthomonadaceae, Rhizobiaceae, Erysipelatoclostridiaceae, Lachnospiraceae, and other taxa in addition to a decrease in the abundance of Frisingicoccus, Ralstonia, Burkholderiaceae, Hungatella, Eisenbergiella, Parabacteroides, Peptostreptococcaceae, Merdibacter, Bilophila, Rikenellaceae, Tannerellaceae, Bacteroidaceae, and Flavonifractor in comparison to controls. Patients with I + D showed significantly higher total SCFA content in feces; increased absolute content of acetic acid, propionic acid, butyric acid, and isoacids; and a significant negative shift in the anaerobic index. The relative levels of the main SCFAs and isoacids in the patient group did not differ significantly from those in the control group. The fecal acetate and isoacid levels correlated with the severity of diarrhea. The fecal butyrate level correlated with the severity of flatulence.

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.

Differences in Fecal Short-Chain Fatty Acids between Alcoholic Fatty Liver-Induced Cirrhosis and Non-alcoholic (Metabolic-Associated) Fatty Liver-Induced Cirrhosis

The objective of this study was to investigate the metabolic activity of the gut microbiota in cirrhosis due to different variants of fatty liver disease (alcoholic vs. non-alcoholic [metabolic-associated] one [AFLD and MAFLD]). The present study included 24 patients with alcoholic liver cirrhosis, 16 patients with MAFLD-related cirrhosis, and 20 healthy controls. The level and spectrum of short-chain fatty acids (SCFAs) were determined via gas-liquid chromatography. All patients with cirrhosis showed a decrease in the total content of SCFAs (p < 0.001) and absolute content of acetate (p < 0.001), propionate (p < 0.001), butyrate (p < 0.001), and isovalerate (p < 0.001). In MAFLD cirrhosis, the metabolic activity of the microbiota was significantly altered compared to patients with alcoholic cirrhosis, as evidenced by a lower total SCFA content (p < 0.001) and absolute content of acetate (p < 0.001), propionate (p < 0.001), and butyrate (p < 0.001); a higher relative content of isovalerate (p < 0.001); and a higher IsoCn/Cn ratio (p < 0.001). Various clinical and laboratory parameters correlate differently with fecal SCFAs and their fractions in cirrhosis due to AFLD and MAFLD. SCFA-producing metabolic activity is reduced more in MAFLD cirrhosis than in alcoholic cirrhosis. According to the etiological factors of cirrhosis, disorders of this metabolic activity may be involved in different pathogenetic pathways.

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.

Clinical Practice Guidelines of the Russian Society for the Study of the Liver, the Russian Gastroenterological Association, the National Scientific Society of Infectious Disease Specialists for the Diagnosis and Treatment of Chronic Hepatitis C

Аim:diagnosis and treatment algorithms in the clinical recommendations intended for general practitioners, gastroenterologists, infectious disease specialists, hepatologists on the of chronic hepatitis C are presented.

Summary.Chronic viral hepatitis C is a socially significant infection, the incidence of which in the Russian Federation remains significantly high. Over the past 10 years, great progress has been made in the treatment of hepatitis C — direct acting antiviral drugs have appeared. The spectrum of their effectiveness allows to achieve a sustained virological response in more than 90 % of cases, even in groups that were not previously considered even as candidates for therapy or were difficult to treat — patients receiving renal replacement therapy, after liver transplantation (or other organs), at the stage of decompensated liver cirrhosis, HIV co-infected, etc. Interferons are excluded from the recommendations due to their low effectiveness and a wide range of adverse events. The indications for the treatment have been expanded, namely, the fact of confirmation of viral replication. The terms of dispensary observation of patients without cirrhosis of the liver have been reduced (up to 12 weeks after the end of therapy). Also, these recommendations present approaches to active screening of hepatitis in risk groups, preventive and rehabilitation measures after the end of treatment.

Conclusion.Great success has been achieved in the treatment of chronic hepatitis C. In most cases, eradication of viral HCV infection is a real task even in patients at the stage of cirrhosis of the liver, with impaired renal function, HIV co-infection, after solid organs transplantation.

Impact of vaccination against the novel coronavirus infection (COVID-19) with Sputnik V on mortality during the delta variant surge

OBJECTIVES

The aim is to study impact of vaccination against the novel coronavirus disease (COVID-19) with Sputnik V on mortality during the period of predominance of the delta variant of SARS-CoV-2.

METHODS

This was a retrospective cohort study of individuals with state health insurance at the Moscow Ambulatory Center. The cohorts included 41,444 persons vaccinated with Sputnik V, 15,566 survivors of COVID-19, and 71,377 non-immune persons. The deaths of patients that occurred from June 1, 2021, to August 31, 2021, were analyzed.

RESULTS

Overall (0.39 % vs. 1.92 %; p < 0.001), COVID-19-related (0.06 % vs. 0.83 %; p < 0.001), and non-COVID mortality (0.33 % vs. 1.09 %; p < 0.001) was lower among vaccinated individuals than among non-immune individuals. The efficacy of vaccination against death from COVID-19 was 96 % [95 % CI 91-98 %] in the general population, 100 % among those aged 18-50 years, 97 % [95 % CI 76-100 %] among those aged 51-70 years, 98 % [95 % CI 90-100 %] among those aged 71-85 years, and 88 % [95 % CI 49-97 %] among those aged > 85 years.

CONCLUSION

COVID-19 vaccination with Sputnik V is associated with a decrease in overall and COVID-19-related mortality and is not with increased non-COVID mortality.

Small Intestinal Bacterial Overgrowth Is Associated with Poor Prognosis in Cirrhosis

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is associated with numerous manifestations of cirrhosis. To determine whether the presence of SIBO affects the prognosis in cirrhosis was the aim of the study.

METHODS

This prospective cohort study included 50 patients. All participants underwent a lactulose hydrogen breath test for SIBO. The follow-up period was 4 years.

RESULTS

SIBO was detected in 26 (52.0%) patients: in 10 (52.6%) patients with compensated cirrhosis and in 16 (51.6%) ones with decompensated cirrhosis. Twelve (46.2%) patients with SIBO and four (16.7%) patients without SIBO died within 4 years (p = 0.009). Among patients with decompensated cirrhosis, 8 (50.0%) patients with SIBO and 3 (20.0%) patients without SIBO died (p = 0.027). Among patients with compensated cirrhosis, four (40.0%) patients with SIBO and one (11.1%) patient without SIBO died (p = 0.045). Among patients with SIBO, there was no difference in mortality between patients with compensated and decompensated cirrhosis (p = 0.209). It was the same for patients without SIBO (p = 0.215). SIBO affects the prognosis only in the first year of follow-up in decompensated cirrhosis, and only in subsequent years in compensated cirrhosis. Presence of SIBO (p = 0.028; HR = 4.2(1.2-14.9)) and serum albumin level (p = 0.027) were significant independent risk factors for death in cirrhosis.

CONCLUSIONS

SIBO is associated with poor prognosis in cirrhosis.

Eubiotic effect of rifaximin is associated with decreasing abdominal pain in symptomatic uncomplicated diverticular disease: results from an observational cohort study

BACKGROUND

Rifaximin effectively treats symptomatic uncomplicated diverticular disease (SUDD) and has shown eubiotic potential (i.e., an increase in resident microbial elements with potential beneficial effects) in other diseases. This study investigated changes in the fecal microbiome of patients with SUDD after repeated monthly treatment with rifaximin and the association of these changes with the severity of abdominal pain.

METHODS

This was a single-center, prospective, observational, uncontrolled cohort study. Patients received rifaximin 400 mg twice a day for 7 days per month for 6 months. Abdominal pain (assessed on a 4-point scale from 0 [no pain] to 3 [severe pain]) and fecal microbiome (assessed using 16 S rRNA gene sequencing) were assessed at inclusion (baseline) and 3 and 6 months. The Spearman's rank test analyzed the relationship between changes in the gut microbiome and the severity of abdominal pain. A p-value ≤ 0.05 was considered statistically significant.

RESULTS

Of the 23 patients enrolled, 12 patients completed the study and were included in the analysis. Baseline abdominal pain levels decreased significantly after 3 (p = 0.036) and 6 (p = 0.008) months of treatment with rifaximin. The abundance of Akkermansia in the fecal microbiome was significantly higher at 3 (p = 0.017) and 6 (p = 0.015) months versus baseline. The abundance of Ruminococcaceae (p = 0.034), Veillonellaceae (p = 0.028), and Dialister (p = 0.036) were significantly increased at 6 months versus baseline, whereas Anaerostipes (p = 0.049) was significantly decreased. The severity of abdominal pain was negatively correlated with the abundance of Akkermansia (r=-0.482; p = 0.003) and Ruminococcaceae (r=-0.371; p = 0.026) but not with Veillonellaceae, Dialister, or Anaerostipes. After 3 months of rifaximin, abdominal pain was significantly less in patients with Akkermansia in their fecal microbiome than in patients without Akkermansia (p = 0.022).

CONCLUSION

The eubiotic effect of rifaximin was associated with decreased abdominal pain in patients with SUDD.

Clostridioides difficile infection in patients with nonalcoholic fatty liver disease-current status

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, leading to fibrosis, cirrhosis and hepatocellular carcinoma and also associated with increased cardiovascular disease mortality. The pathogenesis of NAFLD is not fully understood, although NAFLD is thought to be a hepatic form of metabolic syndrome. There is an increasing understanding of the role of microbiota disturbances in NAFLD pathogenesis, and as with many other conditions affecting the microbiota, NAFLD may be a novel risk factor for Clostridioides difficile (C. difficile) colonization (CDC) and C. difficile infection (CDI). CDI is an emerging nosocomial disease, and community-acquired cases of infection are growing, probably due to an increase in CDC rates. The association of NAFLD with CDI has been shown in only 4 studies to date, three of which included less than 1000 patients, although the frequency of NAFLD in these studies was observed in almost 20% of the total patient cohort. These data revealed that NAFLD is a risk factor for CDI development and, moreover, is a risk factor for intestinal complications of CDI. More studies are needed to investigate this association and move forward CDC and CDI screening efforts for this group of patients.