A novel slow-releasing hydrogen sulfide donor, FW1256, exerts anti-inflammatory effects in mouse macrophages and in vivo.

Exogenous hydrogen sulfide (H2S) is known to exert anti-inflammatory effects both in macrophages and in animal models. In this study, we first showed that NaHS caused a concentration dependent reduction in TNFα and IL-6 secretion in LPS-stimulated RAW264.7 macrophages in the absence of cell death. Thereafter, we screened a series of novel slow H2S donors for similar activity. One such compound, FW1256, concentration dependently decreased TNFα, IL-6, PGE2 and NO generation in LPS-stimulated RAW264.7 macrophages and BMDMs. FW1256 also significantly reduced IL-1ß, COX-2 and iNOS mRNA and protein in LPS-stimulated RAW264.7 macrophages. Mechanistically, FW1256 decreased NFκB activation as evidenced by reduced cytosolic phospho-IκBα levels and reduced nuclear p65 levels in LPS-stimulated RAW264.7 macrophages treated with FW1256. Using a H2S fluorescent probe in FW1256-treated RAW264.7 macrophages, H2S release from FW1256 was apparent over a period of 24h in these cells. Moreover, the effect of FW1256 on TNFα and IL-6 by FW1256 in LPS-stimulated RAW264.7 macrophages was reversed by treatment with the H2S scavenger, vitamin B12a. FW1256 had no cytotoxic effect on LPS-stimulated RAW264.7 macrophages or BMDMs. In vivo, FW1256 administration also reduced IL-1ß, TNFα, nitrate/nitrite and PGE2 levels in LPS-treated mice. We show here a novel slow H2S-releasing compound that exerts anti-inflammatory effects in macrophages and in vivo. FW1256 may be a useful tool to study the biological effects of exogenous H2S and could also have future therapeutic value in inflammatory conditions.

ATM-dependent spontaneous regression of early Eµ-myc-induced murine B-cell leukemia depends on natural killer and T cells.

Mechanisms of spontaneous tumor regression have been difficult to characterize in a systematic manner due to their rare occurrence and the lack of model systems. Here, we provide evidence that early-stage B cells in Eµ-myc mice are tumorigenic and sharply regress in the periphery between 41 and 65 days of age. Regression depended on CD4(+), CD8(+), NK1.1(+) cells and the activation of the DNA damage response, which has been shown to provide an early barrier against cancer. The DNA damage response can induce ligands that enhance immune recognition. Blockade of DNAM-1, a receptor for one such ligand, impaired tumor regression. Hence, Eµ-myc mice provide a model to study spontaneous regression and possible mechanisms of immune evasion or suppression by cancer cells.

H2S Synthesizing Enzymes: Biochemistry and Molecular Aspects.

Hydrogen sulfide (H2S) is a biologically active gas that is synthesized naturally by three enzymes, cystathionine γ-lyase (CSE), cystathionine ß-synthetase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). These enzymes are constitutively present in a wide array of biological cells and tissues and their expression can be induced by a number of disease states. It is becoming increasingly clear that H2S is an important mediator of a wide range of cell functions in health and in disease. This review therefore provides an overview of the biochemical and molecular regulation of H2S synthesizing enzymes both in physiological conditions and their modulation in disease states with particular focus on their regulation in asthma, atherosclerosis and diabetes. The importance of small molecule inhibitors in the study of molecular pathways, the current use of common H2S synthesizing enzyme inhibitors and the relevant characteristics of mice in which these enzymes have been genetically deleted will also be summarized. With a greater understanding of the molecular regulation of these enzymes in disease states, as well as the availability of novel small molecules with high specificity targeted towards H2S producing enzymes, the potential to regulate the biological functions of this intriguing gas H2S for therapeutic effect can perhaps be brought one step closer.

Pandemic-related health literacy: a systematic review of literature in COVID-19, SARS and MERS pandemics.

Introduction: Health literacy plays an essential role in one's ability to acquire and understand critical medical information in the coronavirus disease 2019 (COVID-19) infodemic and in other pandemics. We aimed to summarise the assessment, levels and determinants of pandemic-related health literacy and its associated clinical outcomes. Methods: A systematic review was performed in Medline®, Embase®, PsycINFO®, CINAHL® and four major preprint servers. Observational and interventional studies that evaluated health literacy related to the novel COVID-19, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) were included. Items used in health literacy instruments were grouped under the themes of knowledge, attitudes and practices. Determinants of health literacy were grouped into five domains: sociodemographic, medical, psychological/psychiatric, health systems-related and others. Results: Of the 2,065 articles screened, 70 articles were included. Of these, 21, 17 and 32 studies evaluated health literacy related to COVID-19, SARS and MERS, respectively. The rates of low pandemic health literacy ranged from 4.3% to 57.9% among medical-related populations and from 4.0% to 82.5% among nonmedical populations. Knowledge about the symptoms and transmission of infection, worry about infection, and practices related to mask usage and hand hygiene were most frequently evaluated. Sociodemographic determinants of health literacy were most frequently studied, among which higher education level, older age and female gender were found to be associated with better health literacy. No studies evaluated the outcomes associated with health literacy. Conclusion: The level of pandemic-related health literacy is suboptimal. Healthcare administrators need to be aware of health literacy determinants when formulating policies in pandemics.

Prevalence and risk factors for elevated anxiety symptoms and anxiety disorders in chronic kidney disease: A systematic review and meta-analysis.

BACKGROUND: Anxiety is associated with poor health outcomes among chronic kidney disease (CKD) patients. This review summarizes the prevalence and risk factors associated with elevated anxiety symptoms and disorders among CKD patients. METHODS: Articles evaluating the prevalence and risk factors associated with elevated anxiety symptoms and disorders among CKD patients, as diagnosed via DSM 4th or 5th edition criteria, clinical interviews or validated questionnaires, were searched in Medline®, Embase®, PsychINFO® and CINAHL®. Using random-effects meta-analyses, the prevalence of elevated anxiety symptoms and disorders were estimated. A narrative review on the risk factors associated with elevated anxiety symptoms and disorders was presented. RESULTS: From 4941 articles, 61 studies were included. The pooled prevalence of anxiety disorders (9 studies, n = 1071) among CKD patients across studies was 19% while that of elevated anxiety symptoms (52 studies, n = 10,739) was 43%. Across continents, prevalence of elevated anxiety symptoms was highest in Europe and Asia. Between pre-dialysis and dialysis patients, the prevalence of elevated anxiety symptoms was not statistically different at 31% and 42% respectively. Common risk factors associated with elevated anxiety symptoms included concomitant depression, lower parathyroid hormone levels, increased comorbidities, increased duration of hospitalization, reduced perceived quality of life, and decreased vitality levels. CONCLUSION: Given the high prevalence of anxiety disorders and elevated anxiety symptoms, more studies are required to assess the role and outcomes of anxiety screening among CKD patients. This could facilitate early identification of at-risk patients and potentially improve their clinical outcomes.