Disrupted H2S Signaling by Cigarette Smoking and Alcohol Drinking: Evidence from Cellular, Animal, and Clinical Studies

Roles of Oxidative Stress and Autophagy in Alcohol-Mediated Brain Damage

Excessive alcohol consumption significantly impacts human health, particularly the brain, due to its susceptibility to oxidative stress, which contributes to neurodegenerative conditions. Alcohol metabolism in the brain occurs primarily via catalase, followed by CYP2E1 pathways. Excess alcohol metabolized by CYP2E1 generates reactive oxygen/nitrogen species (ROS/RNS), leading to cell injury via altering many different pathways. Elevated oxidative stress impairs autophagic processes, increasing post-translational modifications and further exacerbating mitochondrial dysfunction and ER stress, leading to cell death. The literature highlights that alcohol-induced oxidative stress disrupts autophagy and mitophagy, contributing to neuronal damage. Key mechanisms include mitochondrial dysfunction, ER stress, epigenetics, and the accumulation of oxidatively modified proteins, which lead to neuroinflammation and impaired cellular quality control. These processes are exacerbated by chronic alcohol exposure, resulting in the suppression of protective pathways like NRF2-mediated antioxidant responses and increased susceptibility to neurodegenerative changes in the brain. Alcohol-mediated neurotoxicity involves complex interactions between alcohol metabolism, oxidative stress, and autophagy regulation, which are influenced by various factors such as drinking patterns, nutritional status, and genetic/environmental factors, highlighting the need for further molecular studies to unravel these mechanisms and develop targeted interventions.

Potential preservative mechanisms of cardiac rehabilitation pathways on endothelial function in coronary heart disease

Cardiac rehabilitation, a comprehensive exercise-based lifestyle and medical management, is effective in decreasing morbidity and improving life quality in patients with coronary heart disease. Endothelial function, an irreplaceable indicator in coronary heart disease progression, is measured by various methods in traditional cardiac rehabilitation pathways, including medicinal treatment, aerobic training, and smoking cessation. Nevertheless, studies on the effect of some emerging cardiac rehabilitation programs on endothelial function are limited. This article briefly reviewed the endothelium-beneficial effects of different cardiac rehabilitation pathways, including exercise training, lifestyle modification and psychological intervention in patients with coronary heart disease, and related experimental models, and summarized both uncovered and potential cellular and molecular mechanisms of the beneficial roles of various cardiac rehabilitation pathways on endothelial function. In exercise training and some lifestyle interventions, the enhanced bioavailability of nitric oxide, increased circulating endothelial progenitor cells (EPCs), and decreased oxidative stress are major contributors to preventing endothelial dysfunction in coronary heart disease. Moreover, the preservation of endothelial-dependent hyperpolarizing factors and inflammatory suppression play roles. On the one hand, to develop more endothelium-protective rehabilitation methods in coronary heart disease, adequately designed and sized randomized multicenter clinical trials should be advanced using standardized cardiac rehabilitation programs and existing assessment methods. On the other hand, additional studies using suitable experimental models are warranted to elucidate the relationship between some new interventions and endothelial protection in both macro- and microvasculature.

Global, regional, and national burden of bladder cancer, 1990-2019: an age-period-cohort analysis based on the Global Burden of Disease 2019 study

OBJECTIVES

Bladder cancer is a common malignancy worldwide, with substantial morbidity and mortality. This study aimed to assess the global, regional, and national burden of bladder cancer from 1990 to 2019 using data from the Global Burden of Disease (GBD) 2019 study and to analyze the trends using an age-period-cohort (APC) model.

STUDY DESIGN

In this cross-sectional study, secondary analyses were conducted to assess the burden of bladder cancer using data from GBD 2019.

METHODS

Bladder cancer prevalence, incidence, mortality, disability-adjusted life years (DALYs), and their age-standardized rates (ASRs) were obtained from the GBD 2019 study. The estimated annual percentage changes (EAPCs) were calculated to quantify the trends in ASRs. An APC analysis was performed to distinguish the effects of age, period, and cohort on the observed temporal trends.

RESULTS

The global prevalence of bladder cancer increased substantially from 1990 to 2019, reaching 2,869,046.4 cases (95% UI: 2,614,200.3-3,114,474.4) in 2019. The age-standardized prevalence rate rose from 20.9 per 100,000 population in 1990 to 37.1 per 100,000 population in 2019, with an EAPC of 1.97 (95% CI: 1.93-2.01). The global burden of bladder cancer, as measured by DALYs, increased from 48.0 per 100,000 population in 1990 to 56.8 per 100,000 population in 2019, with an EAPC of 0.47 (95% CI: 0.4-0.53), demonstrating the growing impact of this disease on population health.

CONCLUSIONS

This study demonstrates a significant increase in prevalence, incidence, mortality, and DALYs, with substantial variations across sociodemographic index (SDI) quintiles and GBD regions. The findings emphasize the need for concerted efforts at the global, regional, and national levels to reduce the burden of bladder cancer through primary prevention, early detection, and improved access to treatment services.

Hydrogen Sulfide and Liver Health: Insights into Liver Diseases

Significance: Hydrogen sulfide (H2S) is a recently recognized gasotransmitter involved in physiological and pathological conditions in mammals. It protects organs from oxidative stress, inflammation, hypertension, and cell death. With abundant expression of H2S-production enzymes, the liver is closely linked to H2S signaling. Recent Advances: Hepatic H2S comes from various sources, including gut microbiota, exogenous sulfur salts, and endogenous production. Recent studies highlight the importance of hepatic H2S in liver diseases such as nonalcoholic fatty liver disease (NAFLD), liver injury, and cancer, particularly at advanced stages. Endogenous H2S production deficiency is associated with severe liver disease, while exogenous H2S donors protect against liver dysfunction. Critical Issues: However, the roles of H2S in NAFLD, liver injury, and liver cancer are still debated, and its effects depend on donor type, dosage, treatment duration, and cell type, suggesting a multifaceted role. This review aimed to critically evaluate H2S production, metabolism, mode of action, and roles in liver function and disease. Future Direction: Understanding H2S's precise roles and mechanisms in liver health will advance potential therapeutic applications in preclinical and clinical research. Targeting H2S-producing enzymes and exogenous H2S sources, alone or in combination with other drugs, could be explored. Quantifying endogenous H2S levels may aid in diagnosing and managing liver diseases. Antioxid. Redox Signal. 40, 122-144.

Recent advances in pyroptosis, liver disease, and traditional Chinese medicine: A review

In recent years, the incidence of liver disease has increased, becoming a major cause of death. Various liver diseases are intricately linked to pyroptosis, which is one of the most common forms of programmed cell death. As a powerful weapon in the fight against liver diseases, traditional Chinese medicine (TCM) can affect pyroptosis via a number of routes, including the classical, nucleotide oligomerization domain-like receptors protein 3/caspase-1/gasdermin D (GSDMD) pathway, the nonclassical lipopolysaccharide/caspase-11/GSDMD pathway, the ROS/caspase-3/gasdermin E pathway, the caspase-9/caspase-3/GSDMD pathway, and the Apaf-1/caspase-11/caspase-3 pathway. In this review, we provide an overview of pyroptosis, the interplay between pyroptosis and liver diseases, and the mechanisms through which TCM regulates pyroptosis in liver diseases. The information used in the text was collected and compiled from the databases of PubMed, Web of Science, Scopus, CNKI, and Wanfang Data up to June 2023. The search was not limited with regard to the language and country of the articles. Research and review articles were included, and papers with duplicate results or unrelated content were excluded. We examined the current understanding of the relationship between pyroptosis and liver diseases as well as the advances in TCM interventions to provide a resource for the identification of potential targets for TCM in the treatment of liver diseases.

Hydrogen Sulfide (H2S) Signaling as a Protective Mechanism against Endogenous and Exogenous Neurotoxicants

In view of the significant role of H₂S in brain functioning, it is proposed that H₂S may also possess protective effects against adverse effects of neurotoxicants. Therefore, the objective of the present review is to discuss the neuroprotective effects of H₂S against toxicity of a wide spectrum of endogenous and exogenous agents involved in the pathogenesis of neurological diseases as etiological factors or key players in disease pathogenesis. Generally, the existing data demonstrate that H₂S possesses neuroprotective effects upon exposure to endogenous (amyloid β, glucose, and advanced-glycation end-products, homocysteine, lipopolysaccharide, and ammonia) and exogenous (alcohol, formaldehyde, acrylonitrile, metals, 6-hydroxydopamine, as well as 1-methyl-4-phenyl- 1,2,3,6- tetrahydropyridine (MPTP) and its metabolite 1-methyl-4-phenyl pyridine ion (MPP)) neurotoxicants. On the one hand, neuroprotective effects are mediated by S-sulfhydration of key regulators of antioxidant (Sirt1, Nrf2) and inflammatory response (NF-κB), resulting in the modulation of the downstream signaling, such as SIRT1/TORC1/CREB/BDNF-TrkB, Nrf2/ARE/HO-1, or other pathways. On the other hand, H₂S appears to possess a direct detoxicative effect by binding endogenous (ROS, AGEs, Aβ) and exogenous (MeHg) neurotoxicants, thus reducing their toxicity. Moreover, the alteration of H₂S metabolism through the inhibition of H₂S-synthetizing enzymes in the brain (CBS, 3-MST) may be considered a significant mechanism of neurotoxicity. Taken together, the existing data indicate that the modulation of cerebral H₂S metabolism may be used as a neuroprotective strategy to counteract neurotoxicity of a wide spectrum of endogenous and exogenous neurotoxicants associated with neurodegeneration (Alzheimer's and Parkinson's disease), fetal alcohol syndrome, hepatic encephalopathy, environmental neurotoxicant exposure, etc. In this particular case, modulation of H₂S-synthetizing enzymes or the use of H₂S-releasing drugs should be considered as the potential tools, although the particular efficiency and safety of such interventions are to be addressed in further studies.

Association between serum 25-hydroxyvitamin d and myeloperoxidase: A cross-sectional study of a general population in China

Background

Several studies have found a strong association between cardiovascular diseases and myeloperoxidase (MPO) as a marker of oxidative stress. Although the anti-inflammatory effects of vitamin D in adults have been validated, evidence about the relationship between MPO and 25(OH)D is lacking. This study aimed to investigate the relationship between MPO and 25(OH)D in the general Chinese population.

Methods

From November 2018 to August 2019, a total of 6414 subjects were enrolled in a tertiary referral hospital in China, which included 3,122 women and 3,292 men. The dependent and independent variables were MPO and 25(OH)D, respectively. The confounders included age, sex, body mass index, waist-hip ratio, smoking status, alcohol drinking status, calcium, and parathyroid hormone concentration.

Results

In the fully adjusted model, we found that MPO decreased by 0.12 (95% CI −0.16, −0.08), ng/mL for each unit (1 nmol/L) increase in 25(OH)D. When 25(OH) D was divided into quartiles, compared with Q1 (< 41.4 nmol/L), the adjusted beta coefficients (β) of MPO in Q2–Q4 were −2.29 (95% CI, −4.31 to −0.27), −4.76 (95% CI, −6.83 to −2.69), and −6.07 (95% CI, −8.23 to −3.92), respectively (P for the trend < 0.0001). When 25(OH) D was divided according to clinical severity, compared with the severely deficient (< 30 nmol/L) s≥ 30, < 50 nmol/L) and sufficient groups (≥ 50 nmol/L) were −2.59 (95% CI, −5.87 to 0.69) and −5.87 (95% CI, −9.17 to −2.57), respectively (P for the trend < 0.0001).

Conclusion

After adjusting for age, sex, BMI, waist-hip ratio, smoking status, alcohol status, calcium, and PTH, circulating 25(OH)D was negatively associated with MPO.

Alcohol-Induced Oxidative Stress and the Role of Antioxidants in Alcohol Use Disorder: A Systematic Review

Alcohol use disorder (AUD) is a highly prevalent, comorbid, and disabling disorder. The underlying mechanism of ethanol neurotoxicity and the involvement of oxidative stress is still not fully elucidated. However, ethanol metabolism has been associated with increased oxidative stress through alcohol dehydrogenase, the microsomal ethanol oxidation system, and catalase metabolic pathways. We searched the PubMed and genome-wide association studies (GWAS) catalog databases to review the literature systematically and summarized the findings focusing on AUD and alcohol abstinence in relation to oxidative stress. In addition, we reviewed the ClinicalTrials.gov resource of the US National Library of Medicine to identify all ongoing and completed clinical trials that include therapeutic interventions based on antioxidants. The retrieved clinical and preclinical studies show that oxidative stress impacts AUD through genetics, alcohol metabolism, inflammation, and neurodegeneration.

Ethanol Metabolism in the Liver, the Induction of Oxidant Stress, and the Antioxidant Defense System

The liver metabolizes ethanol through three enzymatic pathways: alcohol dehydrogenase (ADH), cytochrome p450 (also called MEOS), and catalase. Alcohol dehydrogenase class I (ADH1) is considered the most important enzyme for the metabolism of ethanol, MEOS and catalase (CAT) are considered minor alternative pathways. However, contradicting experiments suggest that the non-ADH1 pathway may have a greater relevance for the metabolism of ethanol than previously thought. In some conditions, ethanol is predominately metabolized to acetaldehyde via cytochrome P450 family 2 (CYP2E1), which is involved in the generation of reactive oxygen species (ROS), mainly through electron leakage to oxygen to form the superoxide (O₂^•−) radical or in catalyzed lipid peroxidation. The CAT activity can also participate in the ethanol metabolism that produces ROS via ethanol directly reacting with the CAT-H₂O₂ complex, producing acetaldehyde and water and depending on the H₂O₂ availability, which is the rate-limiting component in ethanol peroxidation. We have shown that CAT actively participates in lactate-stimulated liver ethanol oxidation, where the addition of lactate generates H₂O₂, which is used by CAT to oxidize ethanol to acetaldehyde. Therefore, besides its known role as a catalytic antioxidant component, the primary role of CAT could be to function in the metabolism of xenobiotics in the liver.

H2S as a Bridge Linking Inflammation, Oxidative Stress and Endothelial Biology: A Possible Defense in the Fight against SARS-CoV-2 Infection?

The endothelium controls vascular homeostasis through a delicate balance between secretion of vasodilators and vasoconstrictors. The loss of physiological homeostasis leads to endothelial dysfunction, for which inflammatory events represent critical determinants. In this context, therapeutic approaches targeting inflammation-related vascular injury may help for the treatment of cardiovascular disease and a multitude of other conditions related to endothelium dysfunction, including COVID-19. In recent years, within the complexity of the inflammatory scenario related to loss of vessel integrity, hydrogen sulfide (H₂S) has aroused great interest due to its importance in different signaling pathways at the endothelial level. In this review, we discuss the effects of H₂S, a molecule which has been reported to demonstrate anti-inflammatory activity, in addition to many other biological functions related to endothelium and sulfur-drugs as new possible therapeutic options in diseases involving vascular pathobiology, such as in SARS-CoV-2 infection.

The interaction of disulfiram and H2S metabolism in inhibition of aldehyde dehydrogenase activity and liver cancer cell growth

Disulfiram (DSF), a sulfur-containing compound, has been used to treat chronic alcoholism and cancer for decades by inactivating aldehyde dehydrogenase (ALDH). Hydrogen sulfide (H₂S) is a new gasotransmitter and regulates various cellular functions by S-sulfhydrating cysteine in the target proteins. H₂S exhibits similar properties to DSF in the sensitization of cancer cells. The interaction of DSF and H₂S on ALDH activity and liver cancer cell survival are not clear. Here it was demonstrated that DSF facilitated H₂S release from thiol-containing compounds, and DSF and H₂S were both capable of regulating ALDH through inhibition of gene expression and enzymatic activity. The supplement of H₂S sensitized human liver cancer cells (HepG2) to DSF-inhibited cell viability. The expression of cystathionine gamma-lyase (a major H₂S-generating enzyme) was lower but ALDH was higher in mouse liver cancer stem cells (Dt81Hepa1-6) in comparison with their parental cells (Hepa1-6), and H₂S was able to inhibit liver cancer stem cell adhesion. In conclusion, these data point to the potential of combining DSF and H₂S for inhibition of cancer cell growth and tumor development by targeting ALDH.