Norfloxacin is more effective than Rifaximin in avoiding bacterial translocation in an animal model of cirrhosis

The effect of rifaximin and lactulose treatments to chronic hepatic encephalopathy rats: An [18F]PBR146 in-vivo neuroinflammation imaging study

INTRODUCTION

Hepatic encephalopathy (HE) is a severe neuropsychiatric complication of liver diseases characterized by neuroinflammation. The efficacies of nonabsorbable rifaximin (RIF) and lactulose (LAC) have been well documented in the treatment of HE. [18F]PBR146 is a translocator protein (TSPO) radiotracer used for in vivo neuroinflammation imaging. This study investigated anti-neuroinflammation effect of RIF or/and LAC in chronic HE rats by [18F]PBR146 micro-PET/CT.

METHODS

Bile duct ligation (BDL) operation induced chronic HE models, and this study included Sham+normal saline (NS), BDL+NS, BDL+RIF, BDL+LAC, and BDL+RIF+LAC groups. Behavioral assessment was performed to analyze the motor function, and fecal samples were collected after successfully established the chronic HE model (more than 28 days post-surgery). In addition, fecal samples collection and micro-PET/CT scans were performed sequentially. And we also collected the blood plasma, liver, intestinal, and brain samples after sacrificing the rats for further biochemical and pathological analyses.

RESULTS

The RIF- and/or LAC-treated BDL rats showed similar behavioral results with Sham+NS group, while the treatment could not reverse the biliary obstruction resulting in sustained liver injury. The RIF or/and LAC treatments can inhibit IFN-γ and IL-10 productions. The global brain uptake values of [18F]PBR146 in BDL+NS group was significantly higher than other groups (p < .0001). The brain regions analysis showed that the basal ganglia, hippocampus, and cingulate cortex had radiotracer uptake differences among groups (all p < .05), which were consistent with the brain immunohistochemistry results. Sham+NS group was mainly enriched in Christensenella, Coprobacillus, and Pseudoflavonifractor. BDL+NS group was mainly enriched in Barnesiella, Alloprevotella, Enterococcus, and Enterorhabdus. BDL+RIF+LAC group was enriched in Parabacteroides, Bacteroides, Allobaculum, Bifidobacterium, and Parasutterella.

CONCLUSIONS

RIF or/and LAC had anti-neuroinflammation in BDL-induced chronic HE rats with gut microbiota alterations. The [18F]PBR146 could be used for monitoring RIF or/and LAC treatment efficacy of chronic HE rats.

Norfloxacin versus alternative antibiotics for prophylaxis of spontaneous bacteria peritonitis in cirrhosis: a systematic review and meta-analysis

BACKGROUND

Spontaneous bacterial peritonitis (SBP) is a life-threatening complication in patients with advanced cirrhosis. Prophylactic Norfloxacin used to be considered effective in SBP prevention, but in recent years its efficacy has been partially compromised by increasing quinolone-resistant bacteria. However, whether the effects of alternative prophylactic regimens are superior to norfloxacin remains controversial. The goal of this study is to compare the effects of norfloxacin with other antibiotics in SBP prophylaxis for cirrhotic patients.

METHODS

We systematically searched Pubmed, Embase, and Cochrane Library Databases. Two reviewers independently identified relevant random control trials (RCTs) comparing the role of norfloxacin and other antibiotics in SBP prevention.

RESULTS

Eight studies comprising 1043 cirrhotic patients were included in this study. Norfloxacin and alternative antibiotics displayed comparable effects in SBP prophylaxis, survival benefit, overall infection prevention, and safety. Subgroup analyses revealed that rifaximin prophylaxis could reduce the recurrence of SBP with fewer adverse events but failed to improve overall survival compared with norfloxacin.

CONCLUSIONS

Other antibiotics are a reasonable alternative to norfloxacin in the prophylaxis of SBP. Rifaximin prophylaxis could be an alternative choose of antibiotic for SBP prevention because of its better protective effect and safety.

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.

The Use of Rifaximin in Patients With Cirrhosis

Rifaximin is an oral nonsystemic antibiotic with minimal gastrointestinal absorption and broad-spectrum antibacterial activity covering both gram-positive and gram-negative organisms. Rifaximin is currently used worldwide in patients with cirrhosis for preventing recurrent HE because its efficacy and safety have been proven by large randomized clinical trials. In the last decade, experimental and clinical evidence suggest that rifaximin could have other beneficial effects on the course of cirrhosis by modulating the gut microbiome and affecting the gut-liver axis, which in turn can interfere with major events of the pathophysiological cascade underlying decompensated cirrhosis, such as systemic inflammatory syndrome, portal hypertension, and bacterial infections. However, the use of rifaximin for prevention or treatment of other complications, including spontaneous bacterial peritonitis or other bacterial infections, is not accepted because evidence by clinical trials is still very weak. The present review deals in the first part with the potential impact of rifaximin on pathogenic mechanisms in liver diseases, whereas in the second part, its clinical effects are critically discussed. It clearly emerges that, because of its potential activity on multiple pathogenic events, the efficacy of rifaximin in the prevention or management of complications other than HE deserves to be investigated extensively. The results of double-blinded, adequately powered randomized clinical trials assessing the effect of rifaximin, alone or in combination with other drugs, on hard clinical endpoints, such as decompensation of cirrhosis, acute-on-chronic liver failure, and mortality, are therefore eagerly awaited.

Non-alcoholic fatty liver disease is associated with bacterial translocation and a higher inflammation response in psoriatic patients

Psoriasis and non-alcoholic fatty liver disease (NAFLD) are both inflammatory diseases. The study objective was to estimate the risk of NAFLD, non-alcoholic steatohepatitis, and liver fibrosis (by liver stiffness and liver biopsy) in patients with psoriasis and to determine the epidemiological, clinical, immunological (TNF-α, IL-2, IL-6, IL-12, IL-17, IL-23, and TGF-β) characteristics, and bacterial translocation. Of the 215 psoriatic patients included, 91 presented NAFLD (prevalence: 42.3%). Compared to patients with psoriasis alone, those with NAFLD were significantly more likely to have metabolic syndrome, diabetes, dyslipidemia, body mass index ≥ 30 kg/m², homeostatic model assessment of insulin resistance ≥ 2.15, and greater psoriasis area severity index. NAFLD patients also had significantly higher levels of TNF-α (p = 0.002) and TGF-β (p = 0.007) and a higher prevalence of bacterial translocation (29.7% vs. 13.7%; p = 0.004). Liver stiffness measurement was over 7.8 kPa in 17.2% (15/87) of NAFLD patients; 13 of these underwent liver biopsy, and 5.7% (5/87) had liver fibrosis, while 1.1% (1/87) had advanced fibrosis or non-alcoholic steatohepatitis. In conclusion the prevalence of NAFLD in patients with psoriasis is high and associated with a higher prevalence of metabolic syndrome features, bacterial translocation and a higher pro-inflammatory state. It is worth mentioning that liver fibrosis and non-alcoholic steatohepatitis are not frequent in this population of patients.

Toll-Like Receptors Recognize Intestinal Microbes in Liver Cirrhosis

Liver cirrhosis is one major cause of mortality in the clinic, and treatment of this disease is an arduous task. The scenario will be even getting worse with increasing alcohol consumption and obesity in the current lifestyle. To date, we have no medicines to cure cirrhosis. Although many etiologies are associated with cirrhosis, abnormal intestinal microbe flora (termed dysbiosis) is a common feature in cirrhosis regardless of the causes. Toll-like receptors (TLRs), one evolutional conserved family of pattern recognition receptors in the innate immune systems, play a central role in maintaining the homeostasis of intestinal microbiota and inducing immune responses by recognizing both commensal and pathogenic microbes. Remarkably, recent studies found that correction of intestinal flora imbalance could change the progress of liver cirrhosis. Therefore, correction of intestinal dysbiosis and targeting TLRs can provide novel and promising strategies in the treatment of liver cirrhosis. Here we summarize the recent advances in the related topics. Investigating the relationship among innate immunity TLRs, intestinal flora disorders, and liver cirrhosis and exploring the underlying regulatory mechanisms will assuredly have a bright future for both basic and clinical research.

A role for intestinal alkaline phosphatase in preventing liver fibrosis

Rationale: Liver fibrosis is frequently associated with gut barrier dysfunction, and the lipopolysaccharides (LPS) -TLR4 pathway is common to the development of both. Intestinal alkaline phosphatase (IAP) has the ability to detoxify LPS, as well as maintain intestinal tight junction proteins and gut barrier integrity. Therefore, we hypothesized that IAP may function as a novel therapy to prevent liver fibrosis.

Methods: Stool IAP activity from cirrhotic patients were determined. Common bile duct ligation (CBDL) and Carbon Tetrachloride-4 (CCl4)-induced liver fibrosis models were used in WT, IAP knockout (KO), and TLR4 KO mice supplemented with or without exogenous IAP in their drinking water. The gut barrier function and liver fibrosis markers were tested.

Results: Human stool IAP activity was decreased in the setting of liver cirrhosis. In mice, IAP activity and genes expression decreased after CBDL and CCl4 exposure. Intestinal tight junction related genes and gut barrier function were impaired in both models of liver fibrosis. Oral IAP supplementation attenuated the decrease in small intestine tight junction protein gene expression and gut barrier function. Liver fibrosis markers were significantly higher in IAP KO compared to WT mice in both models, while oral IAP rescued liver fibrosis in both WT and IAP KO mice. In contrast, IAP supplementation did not attenuate fibrosis in TLR4 KO mice in either model.

Conclusions: Endogenous IAP is decreased during liver fibrosis, perhaps contributing to the gut barrier dysfunction and worsening fibrosis. Oral IAP protects the gut barrier and further prevents the development of liver fibrosis via a TLR4-mediated mechanism.

Gut Microbiota Interventions With Clostridium butyricum and Norfloxacin Modulate Immune Response in Experimental Autoimmune Encephalomyelitis Mice

Gut microbiota has been proposed as an important environmental factor which can intervene and modulate central nervous system autoimmunity. Here, we altered the composition of gut flora with Clostridium butyricum and norfloxacin in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. We found that appropriate C. butyricum (5.0 × 10⁶ CFU/mL intragastrically daily, staring at weaning period of age) and norfloxacin (5 mg/kg intragastrically daily, 1 week prior to EAE induction) treatment could both ameliorate EAE although there are obvious differences in gut microbiota composition between these two interventions. C. butyricum increased while norfloxacin decreased the abundance and diversity of the gut microbiota in EAE mice, and both of the treatments decreased firmicutes/bacteroidetes ratio. In the genus level, C. butyricum treatment increased the abundance of Prevotella while Akkermansia and Allobaculum increased in norfloxacin treatment. Moreover, both interventions reduced Desulfovibroneceae and Ruminococcus species. Although there was discrepancy in the gut microbiota composition with the two interventions, C. butyricum and norfloxacin treatment both reduced Th17 response and increased Treg response in the gastrointestinal tract and extra-gastrointestinal organ systems in EAE mice. And the reduced activity of p38 mitogen-activated kinase and c-Jun N-terminal kinase signaling in spinal cord could be observed in the two interventions. The results suggested that manipulation of gut microbiota interventions should take factors such as timing, duration, and dosage into consideration. The discrepancy in the gut microbiota composition and the similar protective T cells response of C. butyricum and norfloxacin implies that achieving intestinal microecology balance by promoting and/or inhibiting the gut microbiota contribute to the well-being of immune response in EAE mice.

Novel perspectives in the management of decompensated cirrhosis

The current approaches to the management of patients with decompensated cirrhosis are based on targeted strategies aimed at preventing or treating specific complications of the disease. The improved knowledge of the pathophysiological background of advanced cirrhosis, represented by a sustained systemic inflammation strictly linked to a circulatory dysfunction, provides a novel paradigm for the management of these patients, with the ambitious target of modifying the course of the disease by preventing the onset of complications and multiorgan failure; these interventions will eventually improve patients' quality of life, prolong survival and reduce health-care costs. Besides aetiological treatments, these goals could be achieved by persistently antagonizing key pathophysiological events, such as portal hypertension, abnormal bacterial translocation from the gut, liver damage, systemic inflammation, circulatory dysfunction and altered immunological responses. Interestingly, in addition to strategies based on new therapeutic agents, these targets can be tackled by employing drugs that are already used in patients with cirrhosis for different indications or in other clinical settings, including non-absorbable oral antibiotics, non-selective β-blockers, human albumin and statins. The scope of the present Review includes reporting updated information on the treatments that promise to influence the course of advanced cirrhosis and thus act as disease-modifying agents.