Carvedilol attenuates brain damage in mice with hepatic encephalopathy

Inhibition of protein glycation by vasodilatory β-blockers - In vitro studies and in silico analyses

Glycation is defined as a non-enzymatic reaction wherein reducing sugars interact with amino acid residues present in proteins, resulting in the formation of advanced glycation end-products (AGE). This biochemical phenomenon is linked to several pathological conditions, particularly cardiovascular disease (CVD) and diabetes, as it significantly contributes to the onset of endothelial dysfunction and inflammation. Given these connections, vasodilatory β-blockers (VBB) have garnered interest due to their multifaceted pharmacological effects that extend beyond traditional β-adrenergic blockade. These agents not only enhance endothelial function but also exhibit notable antioxidant and anti-inflammatory properties, which may be associated with their capacity to inhibit glycation processes. In our study, we examined these properties through an in vitro and in silico study utilizing bovine serum albumin (BSA) as a model with multiple carbohydrates and aldehydes as glycation agents. Furthermore, we evaluated the binding affinity of VBB to BSA and pro-inflammatory proteins via molecular docking. The results indicated that while VBB were effective in diminishing the rates of protein glycation their effectiveness was generally lower than that of aminoguanidine, a recognized anti-glycation agent. In contrast, molecular docking analyses suggested that the anti-inflammatory properties of VBB may be due to their competition with glycation agents for binding sites on BSA, as well as their interactions with proteins integral to the activation of pro-inflammatory signaling pathways.

Edaravone reduces brain injury in hepatic encephalopathy by upregulation of Nrf2/HO-1 and inhibition of NF-κB, iNOS/NO and inflammatory cytokines

BACKGROUND

Brain damage is the most important complication in patients with hepatic encephalopathy (HE). Oxidative stress and inflammation are essential factors in the progression of brain injury caused by HE. The aim of this study was to investigate the potential therapeutic effect of edaravone and its underlying mechanisms against brain injury associated with HE in mice.

METHODS AND RESULTS

HE was induced by the injection of thioacetamide (200 mg/kg) for 2 days and then mice treated with edaravone (10 or 20 mg/kg/day, ip) for four consecutive days. The brain tissues were dissected for histopathological, biochemical, ELISA, RT-qPCR and immunofluorescence analysis. The results showed that edaravone improved the locomotor function and ameliorated brain histopathological changes in mice with HE. Edaravone inhibited oxidative stress markers by increasing the levels of glutathione, catalase, superoxide dismutase, glutathione reductase and the upregulation of nuclear erythroid 2-related factor (Nrf2)/HO-1 pathway in the brain tissue. Administration of edaravone significantly decreased the expression of p-NF-κB and iNOS. Edaravone treatment reduced the levels of NO, MPO and MMP-9 in the brain of mice. Additionally, the brain levels and expressions of inflammatory cytokines IL-1β, IL-6, TNF-α and IFN-γ were downregulated in mice treated with edaravone.

CONCLUSIONS

These results suggest that edaravone exerts significant neuroprotection by modulating of inflammatory and oxidative responses in HE and may serve as a promising agent for the treatment of brain injury associated with HE.

β-blockers and metabolic modulation: unraveling the complex interplay with glucose metabolism, inflammation and oxidative stress

The growing burden of metabolic disorders manifested by hypertension, type 2 diabetes mellitus, hyperlipidemia, obesity and non-alcoholic fatty liver disease presents a significant global health challenge by contributing to cardiovascular diseases and high mortality rates. Β-blockers are among the most widely used drugs in the treatment of hypertension and acute cardiovascular events. In addition to blocking the receptor sites for catecholamines, third-generation β-blockers with associated vasodilating properties, such as carvedilol and nebivolol, provide a broad spectrum of metabolic effects, including anti-inflammatory and antioxidant properties and a favorable impact on glucose and lipid metabolism. This review aims to report the impact of β-blockers on metabolic modulation based on available literature data. We present an overview of β-blockers and their pleiotropic properties, discuss mechanisms by which these drugs affect cellular metabolism and outline the future perspectives. The influence of β-blockers on glucose metabolism, insulin sensitivity, inflammation and oxidative stress is complex and varies depending on the specific β-blocker used, patient population and underlying health conditions. Recent evidence particularly highlights the potential role of vasodilatory and nitric oxide-mediated properties of nebivolol and carvedilol in improving glycemic control, insulin sensitivity, and lipid metabolism and mitigating oxidative stress and inflammation. It suggests that these drugs may be potential therapeutic options for patients with metabolic disorders, extending beyond their primary role in cardiovascular management.

The Impact of Heart Failure Chronic Treatment Prior to Cardiac Transplantation on Early Outcomes

Background and Objectives: Cardiac transplantation represents the option for patients with end-stage heart failure (HF), providing the best survival rate. However, the postoperative complications of transplant patients remain a challenge for clinicians. The objective of our study was to evaluate the effect of preoperative chronic HF treatment on the occurrence of in-hospital complications. Materials and Methods: We retrospectively included a total of 50 patients who underwent cardiac transplantation between January 2011 and December 2023 from the Emergency Institute for Cardiovascular Diseases and Transplantation of Targu Mures. We correlated the preoperative chronic HF treatment with the postoperative complications by Spearmen's correlation coefficient, respectively. With logistic regression, the associations between the treatment and specific complications were determined. Results: Significant negative correlations were found between Carvedilol treatment with 2-month mortality (r = -0.30; 95% CI: -0.53--0.02; p = 0.03), Ramipril with hospital stay (r = -0.38; 95% CI: -0.60--0.12; p < 0.01) and intensive care unit (ICU) stay (r = -0.37; 95% CI: -0.59--0.11; p = 0.01), and Spironolactone usage with hospitalization duration (r = -0.28; 95% CI: -0.52--0.01; p = 0.04). Furthermore, Carvedilol treatment represented a protective factor against early acute kidney injury (AKI) (OR: 0.22; 95% CI: 0.05-0.91; p = 0.03). Spironolactone treatment was a protective factor against AGR (OR: 0.12; 95% CI: 0.02-0.66; p = 0.01) treatment, in contrast to angiotensin-converting enzyme inhibitor (ACEI) therapy (OR: 5.30; 95% CI: 1.03-27.17; p = 0.04). Conclusions: Pre-transplant Carvedilol treatment was negatively correlated with the 2-month mortality rate. Ramipril and Spironolactone therapy were negatively correlated with hospitalization duration, and Ramipril was additionally correlated with ICU stay. Moreover, Carvedilol therapy represented a protective factor against early AKI. Pre-transplant Spironolactone was associated with lower event rates of AGR, in contrast to ACEI treatment. Prospective studies with larger cohorts are needed in order to draw drastic conclusions.

Therapeutic Effect of Levetiracetam Against Thioacetamide-Induced Hepatic Encephalopathy Through Inhibition of Oxidative Stress and Downregulation of NF-κB, NLRP3, iNOS/NO, Pro-Inflammatory Cytokines and Apoptosis

Hepatic encephalopathy (HE) is a serious brain disorder which associated with neurological and psychiatric manifestations. Oxidative stress and neuroinflammation and apoptosis play main roles in the development of brain damage in HE. Levetiracetam is an antiseizure drug with established antioxidant and anti-inflammatory activities. In the present study we investigated the therapeutic effects of levetiracetam against brain injury in HE and its underlying mechanisms of action. Male C57BL/6 mice were subjected to the induction of HE by the injection of thioacetamide (200 mg/kg) for 2 days. Mice were treated with levetiracetam at two doses (50 or 100 mg/kg/day) for 3 days in the treatment groups. Animals were subjected to a behavioral test and the brain tissues were dissected for histopathological, biochemical, gene expression and immunofluorescence analysis. The results showed that levetiracetam alleviated body weight loss and improved locomotor activity of mice with HE. Levetiracetam treatment decreased the histopathological changes, lipid peroxidation and protein carbonylation while restored the antioxidants (GSH, SOD and CAT) in the brain. Levetiracetam decreased the expression and activity of NF-κB, NOD-like receptor pyrin domain-containing protein 3 (NLRP3) and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IFN-γ) in the brain tissue. Administration of levetiracetam inhibited iNOS/NO pathway and myeloperoxidase (MPO) activity in the brain. Moreover, caspase-3 was decreased and the ratio of Bcl2/Bax was increased in the brain of mice treated with levetiracetam. These findings suggest that levetiracetam may be a promising therapeutic agent for brain injury in HE through inhibiting the oxidative, inflammatory and apoptotic pathways.

Carvedilol attenuates inflammatory reactions of lipopolysaccharide-stimulated BV2 cells and modulates M1/M2 polarization of microglia via regulating NLRP3, Notch, and PPAR-γ signaling pathways

Microglial cells coordinate immune responses in the central nervous system. Carvedilol (CVL) is a non-selective β-blocker with anti-inflammatory and anti-oxidant effects. This study aims to investigate the anti-inflammatory effects and the underlying mechanisms of CVL on lipopolysaccharide (LPS)-induced inflammation in microglial BV2 cells. BV2 cells were stimulated with LPS, and the protective effects of CVL were investigated via measurement of cell viability, reactive oxygen species (ROS), and interleukin (IL)-1β liberation. The protein levels of some inflammatory cascade, Notch, and peroxisome proliferator-activated receptor (PPAR)-γ pathways and relative markers of M1/M2 microglial phenotypes were assessed. Neuroblastoma SH-SY5Y cells were cultured with a BV2-conditioned medium (CM), and the capacity of CVL to protect cell viability was evaluated. CVL displayed a protective effect against LPS stress through reducing ROS and down-regulating of nuclear factor kappa B (NF-κB) p65, NLR family pyrin domain containing-3 (NLRP3), and IL-1β proteins. LPS treatment significantly increased the levels of the M1 microglial marker inducible nitric oxide synthase (iNOS) and M1-associated cleaved-NOTCH1 and hairy and enhancer of split-1 (HES1) proteins. Conversely, LPS treatment reduced the levels of the M2 marker arginase-1 (Arg-1) and PPAR-γ proteins. CVL pre-treatment reduced the protein levels of iNOS, cleaved-NOTCH1, and HES1, while increased Arg-1 and PPAR-γ. CM of CVL-primed BV2 cells significantly improved SH-SY5Y cell viability as compared with the LPS-induced cells. CVL suppressed ROS production and alleviated the expression of inflammatory markers in LPS-stimulated BV2 cells. Our results demonstrated that targeting Notch and PPAR-γ pathways as well as directing BV2 cell polarization toward the M2 phenotype may provide a therapeutic strategy to suppress neuroinflammation by CVL.

Dahuang-Wumei decoction protects against hepatic encephalopathy in mice: Behavioural, biochemical, and molecular evidence

BACKGROUND

Disturbance of the blood‒brain barrier (BBB) and associated inflammatory responses are observed in patients with hepatic encephalopathy (HE) and can cause long-term complications. Dahuang-Wumei decoction (DWD) is a renowned traditional Chinese herbal medicine with a long history of clinical use and has been widely employed as an effective treatment for hepatic encephalopathy (HE). Despite its established efficacy, the precise mechanisms underlying the therapeutic effects of DWD have not been fully elucidated.

PURPOSE

The present study aimed to comprehensively explore the potential effects and underlying molecular mechanisms of DWD on HE through an integrated investigation that included both in vivo and in vitro experiments.

METHODS

In the present study, carbon tetrachloride (CCl4) and thioacetamide (TAA) were used to establish an HE model in mice. The therapeutic effects of DWD on liver injury, fibrosis, brain injury, behaviour, and consciousness disorders were evaluated in vivo. C8-D1A and bEnd.3 cells were used to construct a BBB model in vitro. The effects of DWD on proinflammatory factor expression, BBB damage and the Wnt/β-catenin pathway were detected in vivo and in vitro.

RESULTS

Our results showed that DWD can improve liver injury and fibrosis and brain damage and inhibit neurofunctional and behavioural disorders in mice with HE. Afterwards, we found that DWD decreased the levels of proinflammatory factors and suppressed BBB disruption by increasing the levels of junction proteins in vivo and vitro. Further studies verified that the Wnt/β-catenin pathway may play a pivotal role in mediating the inhibitory effect of DWD on HE.

CONCLUSION

These results demonstrated that DWD can treat HE by preventing BBB disruption, and the underlying mechanisms involved were associated with the activation of the Wnt/β-catenin pathway and the inhibition of inflammatory responses.

Prognostic value of virtual portal pressure gradient response in compensated cirrhotic patients treated with carvedilol

AIM

This study aimed to assess the prognostic significance of virtual portal pressure gradient (vPPG) response to carvedilol in patients with compensated cirrhosis (CC).

METHODS

Compensated cirrhosis patients with high-risk varices were prospectively enrolled to receive carvedilol for prevention of first variceal hemorrhage (VH) and followed up for 1 year. The vPPG response was defined as a reduction of vPPG >10% from baseline after 1-month therapy. Logistic and Cox regression analyses were performed to identify independent predictors for vPPG response and first decompensation, respectively. Competitive risk models were constructed to predict disease progression, and validated using the C-index, Kaplan-Meier analysis, competitive risk analysis, and calibration curves.

RESULTS

A total of 129 patients completed this study, of whom 56 (43.4%) achieved vPPG response and were referred as vPPG responders. Baseline vPPG, red color sign, Model for End-stage Liver Disease score, serum monocyte chemoattractant protein-1 (MCP-1), and laminin levels significantly correlated with vPPG response, which itself was further documented as an independent predictor of VH, ascites, and overall decompensation events in CC. Moreover, the red color sign or Child-Turcotte-Pugh score effectively predicted VH, while ascites correlated well with portal flow velocity or MCP-1. The predictive models for VH and ascites showed a good discrimination with C-index values of 0.747 and 0.689 respectively, and the high consistency on calibration curves.

CONCLUSION

The vPPG response could be used as a noninvasive tool for prediction of disease progression in patients with CC.

The Mechanism of Hepatic Encephalopathy Induced by Thioacetamide Based on Metabolomics and Proteomics: A Preliminary Study

Hepatic encephalopathy (HE) is a central nervous system dysfunction syndrome caused by acute and chronic liver failure or various portal systemic shunt disorders. HE arises from metabolic disorder and excludes other known types of encephalopathy. HE is a major cause of death in people with liver disease. Early diagnosis and timely treatment are key to improving HE prognosis. Herein, we established a model of HE and performed metabolomics to identify 50 significantly differential metabolites between the HE group and control group. The main metabolic pathways associated with these differential metabolites were the purine metabolism, pyrimidine metabolism, aminoacyl tRNA biosynthesis, and glucose metabolism. Through proteomics analysis, we identified 226 significantly differential proteins (52 up-regulated and 174 down-regulated). The main (Kyoto Encyclopedia of Genes and Genomes) enrichment pathways were the Staphylococcus aureus infection, vitamin digestion and absorption, and complement and coagulation cascades. Through the conjoint analysis of proteomics and metabolomics, the differentially present proteins and metabolites were found to be involved in vitamin digestion and absorption, and ferroptosis pathways. In HE, malondialdehyde was significantly elevated, but glutathione was significantly diminished, and the redox balance was destroyed, thus leading to changes in proteins' levels associated with the ferroptosis pathway. In conclusion, this study preliminarily explored the molecular and metabolic mechanisms underlying HE.

Levetiracetam attenuates experimental ulcerative colitis through promoting Nrf2/HO-1 antioxidant and inhibiting NF-κB, proinflammatory cytokines and iNOS/NO pathways

Ulcerative colitis (UC) is a serious inflammatory disease of the colon. The pathogenic mechanisms of UC involve the activation of inflammatory and oxidative stress responses in the colon. Levetiracetam is an antiepileptic drug with anti-inflammatory and antioxidant effects. The aim of this study was to investigate the potential protective effect of levetiracetam against UC in a mouse model. UC was induced in mice by intrarectal administration of acetic acid and then mice were treated with levetiracetam (50 or 100 mg/kg/day, i.p.) for three days. The colonic tissue samples were dissected for biochemical, RT-PCR and immunofluorescence analysis. Results showed that levetiracetam treatment significantly decreased colonic mucosal injury as evidenced by the macroscopic and histopathological analysis. Levetiracetam induced Nrf2/HO-1 and antioxidants while reduced lipid peroxidation and myeloperoxidase activity in colon tissue. Levetiracetam treatment decreased NF-κB activity and the expression of proinflammatory mediators TNF-α, IL-6, IL-1β, IFN-γ, MCP-1 and ICAM-1. The colonic levels of anti-inflammatory cytokines IL-10 and TGF-β1 were increased by levetiracetam treatment. Furthermore, levetiracetam significantly diminished iNOS expression and NO production in colon tissue. These findings suggest that levetiracetam ameliorates the severity of UC in mice through the regulation of inflammatory and oxidative responses.

Review article: controversies surrounding the use of carvedilol and other beta blockers in the management of portal hypertension and cirrhosis

BACKGROUND

Advanced chronic liver disease is an increasing cause of premature morbidity and mortality in the UK. Portal hypertension is the primary driver of decompensation, including the development of ascites, hepatic encephalopathy and variceal haemorrhage. Non-selective beta blockers (NSBB) reduce portal pressure and are well established in the prevention of variceal haemorrhage. Carvedilol, a newer NSBB, is more effective at reducing portal pressure due to additional α-adrenergic blockade and has additional anti-oxidant, anti-inflammatory and anti-fibrotic effects.

AIM

To summarise the available evidence on the use of beta blockers, specifically carvedilol, in cirrhosis, focussing on when and why to start METHODS: We performed a comprehensive literature search of PubMed for relevant publications.

RESULTS

International guidelines advise the use of NSBB in primary prophylaxis against variceal haemorrhage in those with high-risk varices, with substantial evidence of efficacy comparable with endoscopic band ligation (EBL). NSBB are also well established in secondary prophylaxis, in combination with EBL. More controversial is their use in patients without large varices, but with clinically significant portal hypertension. However, there is gathering evidence that NSBB, particularly carvedilol, reduce the risk of decompensation and improve survival. While caution is advised in patients with advanced cirrhosis and refractory ascites, recent evidence suggests that NSBB can continue to be used safely, and that premature discontinuation may be detrimental.

CONCLUSIONS

With increasing evidence of benefit independent of variceal bleeding, namely retardation of decompensation and improvement in survival, it is time to consider whether carvedilol should be offered to all patients with advanced chronic liver disease.

Cellular Pathogenesis of Hepatic Encephalopathy: An Update

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome derived from metabolic disorders due to various liver failures. Clinically, HE is characterized by hyperammonemia, EEG abnormalities, and different degrees of disturbance in sensory, motor, and cognitive functions. The molecular mechanism of HE has not been fully elucidated, although it is generally accepted that HE occurs under the influence of miscellaneous factors, especially the synergistic effect of toxin accumulation and severe metabolism disturbance. This review summarizes the recently discovered cellular mechanisms involved in the pathogenesis of HE. Among the existing hypotheses, ammonia poisoning and the subsequent oxidative/nitrosative stress remain the mainstream theories, and reducing blood ammonia is thus the main strategy for the treatment of HE. Other pathological mechanisms mainly include manganese toxicity, autophagy inhibition, mitochondrial damage, inflammation, and senescence, proposing new avenues for future therapeutic interventions.