Potential of Mitochondria-Targeted Antioxidants to Prevent Oxidative Stress in Pancreatic β-cells

The emerging importance of the α-keto acid dehydrogenase complexes in serving as intracellular and intercellular signaling platforms for the regulation of metabolism

The α-keto acid dehydrogenase complex (KDHc) class of mitochondrial enzymes is composed of four members: pyruvate dehydrogenase (PDHc), α-ketoglutarate dehydrogenase (KGDHc), branched-chain keto acid dehydrogenase (BCKDHc), and 2-oxoadipate dehydrogenase (OADHc). These enzyme complexes occupy critical metabolic intersections that connect monosaccharide, amino acid, and fatty acid metabolism to Krebs cycle flux and oxidative phosphorylation (OxPhos). This feature also imbues KDHc enzymes with the heightened capacity to serve as platforms for propagation of intracellular and intercellular signaling. KDHc enzymes serve as a source and sink for mitochondrial hydrogen peroxide (mtH2O2), a vital second messenger used to trigger oxidative eustress pathways. Notably, deactivation of KDHc enzymes through reversible oxidation by mtH2O2 and other electrophiles modulates the availability of several Krebs cycle intermediates and related metabolites which serve as powerful intracellular and intercellular messengers. The KDHc enzymes also play important roles in the modulation of mitochondrial metabolism and epigenetic programming in the nucleus through the provision of various acyl-CoAs, which are used to acylate proteinaceous lysine residues. Intriguingly, nucleosomal control by acylation is also achieved through PDHc and KGDHc localization to the nuclear lumen. In this review, I discuss emerging concepts in the signaling roles fulfilled by the KDHc complexes. I highlight their vital function in serving as mitochondrial redox sensors and how this function can be used by cells to regulate the availability of critical metabolites required in cell signaling. Coupled with this, I describe in detail how defects in KDHc function can cause disease states through the disruption of cell redox homeodynamics and the deregulation of metabolic signaling. Finally, I propose that the intracellular and intercellular signaling functions of the KDHc enzymes are controlled through the reversible redox modification of the vicinal lipoic acid thiols in the E2 subunit of the complexes.

"ATAD3C regulates ATAD3A assembly and function in the mitochondrial membrane"

Mitochondrial ATAD3A is an ATPase Associated with diverse cellular Activities (AAA) domain containing enzyme, involved in the structural organization of the inner mitochondrial membrane and of increasing importance in childhood disease. In humans, two ATAD3A paralogs arose by gene duplication during evolution: ATAD3B and ATAD3C. Here we investigate the cellular activities of the ATAD3C paralog that has been considered a pseudogene. We detected unique ATAD3C peptides in HEK 293T cells, with expression similar to that in human tissues, and showed that it is an integral membrane protein that exposes its carboxy-terminus to the intermembrane space. Overexpression of ATAD3C, but not of ATAD3A, in fibroblasts caused a decrease in cell proliferation and oxygen consumption rate, and an increase of cellular ROS. This was due to the incorporation of ATAD3C monomers in ATAD3A complex in the mitochondrial membrane reducing its size. Consistent with a negative regulation of ATAD3A function in mitochondrial membrane organization, ATAD3C expression led to increased accumulation of respiratory chain dimeric CIII in the inner membrane, to the detriment to that assembled in respiratory supercomplexes. Our results demonstrate a negative dominant role of the ATAD3C paralog with implications for mitochondrial OXPHOS function and suggest that its expression regulates ATAD3A in the cell.

Pancreatic Beta-cell Dysfunction in Type 2 Diabetes

Pancreatic β-cells produce and secrete insulin to maintain blood glucose levels within a narrow range. Defects in the function and mass of β-cells play a significant role in the development and progression of diabetes. Increased β-cell deficiency and β-cell apoptosis are observed in the pancreatic islets of patients with type 2 diabetes. At an early stage, β-cells adapt to insulin resistance, and their insulin secretion increases, but they eventually become exhausted, and the β-cell mass decreases. Various causal factors, such as high glucose, free fatty acids, inflammatory cytokines, and islet amyloid polypeptides, contribute to the impairment of β-cell function. Therefore, the maintenance of β-cell function is a logical approach for the treatment and prevention of diabetes. In this review, we provide an overview of the role of these risk factors in pancreatic β-cell loss and the associated mechanisms. A better understanding of the molecular mechanisms underlying pancreatic β-cell loss will provide an opportunity to identify novel therapeutic targets for type 2 diabetes.

Association Between Serum Lipids and Survival in Patients With Amyotrophic Lateral Sclerosis: A Meta-analysis and Population-Based Study

BACKGROUND AND OBJECTIVE

To explore the association between lipids, polygenic profile scores (PPS) for biomarkers of lipid metabolism, markers of disease severity, and survival in patients with amyotrophic lateral sclerosis (ALS).

METHODS

We meta-analyzed the current literature on the prognostic value of lipids in patients with ALS. Subsequently, we evaluated the relationship between lipid levels at diagnosis, clinical disease stage, and survival in all consecutive patients diagnosed in the Netherlands. We determined the hazard ratio (HR) of each lipid for overall survival, defined as death from any cause. A subset of patients was matched to a previous genome-wide association study; data were used to calculate PPS for biomarkers of lipid metabolism and to determine the association between observed lipid levels at diagnosis and survival.

RESULTS

Meta-analysis of 4 studies indicated that none of the biomarkers of the lipid metabolism were statistically significantly associated with overall survival; there was, however, considerable heterogeneity between study results. Using individual patient data (N = 1,324), we found that increased high-density lipoprotein (HDL) cholesterol was associated with poorer survival (HR of 1.33 (95% CI 1.14-1.55, p < 0.001)). The correlation between BMI and HDL cholesterol (Pearson r -0.26, 95% CI -0.32 to -0.20) was negative and between BMI and triglycerides (TG) positive (Pearson r 0.18, 95% CI 0.12-0.24). Serum concentrations of total cholesterol and LDL cholesterol were lower in more advanced clinical stages (both p < 0.001). PPS for biomarkers of lipid metabolism explained 1.2%-13.1% of their variance at diagnosis. None of the PPS was significantly associated with survival (all p > 0.50).

DISCUSSION

Lipids may contain valuable information about disease severity and prognosis, but their main value may be driven as a consequence of disease progression. Our results underscore that gaining further insight into lipid metabolism and longitudinal data on serum concentrations of the lipid profile could improve the monitoring of patients and potentially further disentangle ALS pathogenesis.

Biomarkers of growth and carbohydrate metabolism in neonatal rats supplemented with fish oil and/or antioxidants during intermittent hypoxia

OBJECTIVE

Extremely low gestational age neonates (ELGANs) experience frequent intermittent hypoxia (IH) episodes during therapeutic oxygen. ELGANs exhibit poor postnatal growth requiring lipid supplementation. Lipids are targets of reactive oxygen species resulting in lipid peroxidation and cell death, particularly in preterm infants with compromised antioxidant systems. We tested the hypothesis that early supplementation with lipids and/or antioxidants promotes growth and influences biomarkers of carbohydrate metabolism in neonatal rats exposed to IH.

DESIGN

Newborn rats (n = 18/group) were exposed to brief hypoxia (12% O₂) during hyperoxia (50% O₂), or room air (RA), from birth (P0) to P14 during which they received daily oral supplementation with: 1) fish oil; 2) Coenzyme Q10 (CoQ10) in olive oil; 3) glutathione nanoparticles (nGSH); 4) fish oil+CoQ10; or 5) olive oil. At P21, plasma samples were assessed for glucose, insulin, glucokinase (GCK), glucagon, glucagon-like peptide (GLP)-1, growth hormone (GH), corticosterone, and ghrelin. Liver was assessed for histopathology, apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL stain), and GH, insulin-like growth factor (IGF)-I, GH binding protein (GHBP), and IGF binding protein (IGFBP)-3.

RESULTS

Neonatal IH resulted in decreased liver weight and liver/body weight ratios, as well as hepatocyte swelling, steatosis, and apoptosis, which were attenuated with fish oil, nGSH, and combined fish oil+CoQ10. IH also decreased plasma glucose, insulin, GCK, and ghrelin, but increased GLP-1. All treatments improved plasma glucose in IH, but insulin was higher with CoQ10 and nGSH only. Glucagon was increased with CoQ10, fish oil, and CoQ10 + fish oil, while corticosterone was higher with nGSH and CoQ10 + fish oil. IGF-I and IGFBP-3 were significantly higher in the liver with CoQ10 in IH, while deficits in GH were noted with CoQ10 and fish oil in RA and IH. Treatment with nGSH and combined CoQ10 + fish oil reduced IGF-I in RA and IH but increased IGFBP-3.

CONCLUSIONS

Neonatal IH impairs liver growth with significant hepatocyte damage. Of all supplements in IH, nGSH and combined fish oil+CoQ10 were most effective for preserving liver growth and carbohydrate metabolism. Data suggest that these supplements may improve poor postnatal organ and body growth; and metabolic dysfunction associated with neonatal IH.

Comparative effectiveness of playing golf to Nordic walking and walking on acute physiological effects on cardiometabolic markers in healthy older adults: a randomised cross-over study

Objectives

The acute effects of aerobic exercise on cardiometabolic markers are well documented in younger healthy individuals, but the same effects in older adults have not been elucidated. As such, this study compares the acute effects of three different types of age-appropriate aerobic exercises on cardiometabolic markers.

Methods

Healthy older golfers (n=25, 16 male and 9 female, 68±4 years) were enrolled in a randomised cross-over experiment. We compared the effects of three different acute aerobic exercises (18-hole golf, 6 km Nordic walk, 6 km walk) on blood pressure, blood glucose and blood lipid profile in a real-life environment.

Results

In the between-group comparison, playing golf resulted in a difference in blood glucose (golf: 0.01±1.0 mmol/L, walk: 1.3±0.9 mmol/L, p<0.001) compared with walking and triglycerides (golf: 0.13±0.2 mmol/L, Nordic walk: 0.31±0.2 mmol/L, walk: 0.23±0.2 mmol, p=0.012) and high-density lipoprotein cholesterol (golf: 0.04±0.06 mmol/L, Nordic walk: -0.02±0.06 mmol/L, walk: -0.02±0.07 mmol/L, p=0.002) compared with Nordic walking and walking. In addition, all groups had significant decreases (p<0.001) in systolic blood pressure, and Nordic walking and walking also demonstrated a decrease in diastolic blood pressure (p<0.05).

Conclusion

Acute bouts of aerobic exercise improved cardiovascular profile in healthy older adults. Despite the lower exercise intensity of golf, the longer duration and higher energy expenditure appeared to have a more positive effect on lipid profile and glucose metabolism compared with Nordic walking and walking.

Trial registration number

ISRCTN10007294.

Nutraceutical activation of Sirt1: a review

The deacetylase sirtuin 1 (Sirt1), activated by calorie restriction and fasting, exerts several complementary effects on cellular function that are favourable to healthspan; it is often thought of as an 'anti-aging' enzyme. Practical measures which might boost Sirt1 activity are therefore of considerable interest. A number of nutraceuticals have potential in this regard. Nutraceuticals reported to enhance Sirt1 synthesis or protein expression include ferulic acid, tetrahydrocurcumin, urolithin A, melatonin, astaxanthin, carnosic acid and neochlorogenic acid. The half-life of Sirt1 protein can be enhanced with the natural nicotinamide catabolite N1-methylnicotinamide. The availability of Sirt1's obligate substrate NAD+ can be increased in several ways: nicotinamide riboside and nicotinamide mononucleotide can function as substrates for NAD+ synthesis; activators of AMP-activated kinase-such as berberine-can increase expression of nicotinamide phosphoribosyltransferase, which is rate limiting for NAD+ synthesis; and nutraceutical quinones such as thymoquinone and pyrroloquinoline quinone can boost NAD+ by promoting oxidation of NADH. Induced ketosis-as via ingestion of medium-chain triglycerides-can increase NAD+ in the brain by lessening the reduction of NAD+ mediated by glycolysis. Post-translational modifications of Sirt1 by O-GlcNAcylation or sulfonation can increase its activity, suggesting that administration of glucosamine or of agents promoting hydrogen sulfide synthesis may aid Sirt1 activity. Although resveratrol has poor pharmacokinetics, it can bind to Sirt1 and activate it allosterically-as can so-called sirtuin-activating compound drugs. Since oxidative stress can reduce Sirt1 activity in multiple ways, effective antioxidant supplementation that blunts such stress may also help preserve Sirt1 activity in some circumstances. Combination nutraceutical regimens providing physiologically meaningful doses of several of these agents, capable of activating Sirt1 in complementary ways, may have considerable potential for health promotion. Such measures may also amplify the benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors in non-diabetic disorders, as these benefits appear to reflect upregulation of Sirt1 and AMP-activated protein kinase activities.

Effect of HEAT therapy in patiEnts with type 2 Diabetes mellitus (HEATED): protocol for a randomised controlled trial

INTRODUCTION

The burden of type 2 diabetes mellitus (T2DM) is increasing worldwide. Heat therapy has been found effective in improving glycaemic control. However, to date, there is a lack of randomised controlled studies investigating the efficacy of heat therapy in T2DM. Therefore, we aim to investigate whether heat therapy with natural thermal mineral water can improve glycaemic control in patients with T2DM.

METHODS AND ANALYSIS

The HEAT therapy in patiEnts with type 2 Diabetes mellitus (HEATED) Study is a single-centre, two-arm randomised controlled trial being conducted at Harkány Thermal Rehabilitation Centre in Hungary. Patients with T2DM will be randomly assigned to group A (bath sessions in 38°C natural thermal mineral water) and group B (baths in thermoneutral water (30°C-32°C)). Both groups will complete a maximum of 5 weekly visits, averaging 50-60 visits over the 12-week study. Each session will last 30 min, with a physical check-up before the bath. At baseline, patients' T2DM status will be investigated thoroughly. Possible microvascular and macrovascular complications of T2DM will be assessed with physical and laboratory examinations. The short form-36 questionnaire will assess the quality of life. Patients will also be evaluated at weeks 4, 8 and 12. The primary endpoint will be the change of glycated haemoglobin from baseline to week 12. An estimated 65 patients will be enrolled per group, with a sample size re-estimation at the enrolment of 50% of the calculated sample size.

ETHICS AND DISSEMINATION

The study has been approved by the Scientific and Research Ethics Committee of the Hungarian Medical Research Council (818-2/2022/EÜIG). Written informed consent is required from all participants. We will disseminate our results to the medical community and will publish our results in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT05237219.

Importance of ideal cardiovascular health metrics in the risk of colorectal cancer among people aged 50 years or older: a UK Biobank cohort study

OBJECTIVE

To explore the correlation between the ideal cardiovascular health metrics (ICVHMs) and the incidence of colorectal cancer (CRC) among people aged 50 years or older.

DESIGN

Prospective cohort study.

SETTING

The UK Biobank, a prospective cohort of middle-aged participants recruited between 2006 and 2010.

PARTICIPANTS

The study included 342 226 participants from the UK Biobank aged 50 years or older without prevalent cancer.

EXPOSURE

The ICVHMs consist of four behavioural factors (abstinence from smoking, ideal body mass index (BMI), physical activity at goal and consumption of healthy diet) and three cardiometabolic factors (untreated total cholesterol <200 mg/dL, untreated blood pressure <120/80 mm Hg and untreated fasting plasma glucose <100 mg/dL).

MAIN OUTCOMES

The outcome was ascertained by linkage to cancer and death registries using the International Classification of Diseases, Tenth codes C18-C20.

RESULTS

During a median follow-up time of 8.72 years, 3060 CRC cases were identified. Compared with the reference (participants with ICVHMs ≤2), the multivariable-adjusted HRs for subgroups with 3, 4, 5 and ≥6 ICVHM factors were 0.98 (95% CI 0.85 to 1.12), 0.90 (95% CI 0.77 to 1.02), 0.85 (95% CI 0.71 to 0.98) and 0.69 (95% CI 0.48 to 0.90), respectively. Among the seven ICVHM factors, lower BMI, healthier diet and ideal fasting plasma glucose were significantly associated with lower risk of CRC (HR: 0.86, 95% CI 0.78 to 0.95; HR: 0.92, 95% CI 0.84 to 0.99; HR: 0.90, 95% CI 0.80 to 0.99).

CONCLUSIONS

Adherence to the ICVHMs was associated with a lower risk of CRC among people aged 50 years or older. Among the seven ICVHM factors, BMI, diet and fasting plasma glucose played a more critical role in the prevention of CRC. These findings imply that adherence to ICVHMs should be encouraged to reduce the burden of cardiovascular disease as well as CRC.

Safety and efficacy of intravenous or topical tranexamic acid administration in surgery: a protocol for a systematic review and network meta-analysis

INTRODUCTION

Tranexamic acid (TXA) has become a widely used antifibrinolytic drug for reducing bleeding in surgery. However, adverse events, such as seizures, pulmonary embolism and deep vein thrombosis, limit its application. To date, insufficient attention has been devoted to determining the optimal dosage and administration route of TXA in the field of surgery. Thus, this study uses the network meta-analysis method, relying on its characteristics of combining direct comparison and indirect comparison, to analyse the safety and efficacy of different doses (high, medium, low) of intravenous injection or of topical application of TXA.

METHODS AND ANALYSIS

We will search the PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science and China National Knowledge Internet databases using a strategy that combines the terms TXA, randomised controlled trials and embolism (or haemorrhage, blood transfusion, seizure, mortality). Two reviewers will independently screen all identified abstracts for eligibility and evaluate the risk-of-bias of the included studies using the Cochrane risk of bias tool for randomised controlled studies. We will conduct a systematic review and network meta-analysis. We plan to investigate heterogeneity by performing subgroup analysis and sensitivity analysis, and we will also consider the dose-response relationship between the optimal dose and a better routine. We will assess the overall certainty of the evidence for each outcome using the Grading Recommendations Assessment, Development and Evaluation approach ETHICS AND DISSEMINATION: No ethics approval will be sought, as no original data will be collected for this review. Findings will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42021281206.

Coenzyme Q10 deficiency can be expected to compromise Sirt1 activity

For reasons that remain unclear, endogenous synthesis and tissue levels of coenzyme Q10 (CoQ10) tend to decline with increasing age in at least some tissues. When CoQ10 levels are sufficiently low, this compromises the efficiency of the mitochondrial electron transport chain, such that production of superoxide by site 2 increases and the rate of adenosine triphosphate production declines. Moreover, CoQ10 deficiency can be expected to decrease activities of Sirt1 and Sirt3 deacetylases, believed to be key determinants of health span. Reduction of the cytoplasmic and mitochondrial NAD⁺/NADH ratio consequent to CoQ10 deficit can be expected to decrease the activity of these deacetylases by lessening availability of their obligate substrate NAD⁺. The increased oxidant production induced by CoQ10 deficiency can decrease the stability of Sirt1 protein by complementary mechanisms. And CoQ10 deficiency has also been found to lower mRNA expression of Sirt1. An analysis of the roles of Sirt1/Sirt3 in modulation of cellular function helps to rationalise clinical benefits of CoQ10 supplementation reported in heart failure, hypertension, non-alcoholic fatty liver disease, metabolic syndrome and periodontal disease. Hence, correction of CoQ10 deficiency joins a growing list of measures that have potential for amplifying health protective Sirt1/Sirt3 activities.

Ferroptosis Promotes Cyst Growth in Autosomal Dominant Polycystic Kidney Disease Mouse Models

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD), the most common inherited kidney disease, is regulated by different forms of cell death, including apoptosis and autophagy. However, the role in ADPKD of ferroptosis, a recently discovered form of cell death mediated by iron and lipid metabolism, remains elusive.

METHODS

To determine a pathophysiologic role of ferroptosis in ADPKD, we investigated whether the absence of Pkd1 (encoding polycystin-1) affected the expression of key factors involved in the process of ferroptosis, using Western blot and qRT-PCR analysis in Pkd1 mutant renal cells and tissues. We also examined whether treatment with erastin, a ferroptosis inducer, and ferrostain-1, a ferroptosis inhibitor, affected cyst growth in Pkd1 mutant mouse models.

RESULTS

We found that kidney cells and tissues lacking Pkd1 exhibit extensive metabolic abnormalities, including reduced expression of the system Xc- amino acid antiporter (critical for import of cystine), of iron exporter (ferroportin), and of GPX4 (a key and negative regulator of ferroptosis). The abnormalities also include increased expression of iron importers (TfR1, DMT1) and HO-1, which in turn result in high iron levels, low GSH and GPX4 activity, increased lipid peroxidation, and propensity to ferroptosis. We further found that erastin increased, and ferrostatin-1 inhibited ferroptotic cell death and proliferation of Pkd1-deficient cells in kidneys from Pkd1 mutant mice. A lipid peroxidation product increased in Pkd1-deficient cells, 4HNE, promoted the proliferation of survived Pkd1 mutant cells via activation of Akt, S6, Stat3, and Rb during the ferroptotic process, contributing to cyst growth.

CONCLUSION

These findings indicate that ferroptosis contributes to ADPKD progression and management of ferroptosis may be a novel strategy for ADPKD treatment.

Pro-inflammatory cytokine profile is present in the serum of Mexican patients with different stages of diabetic retinopathy secondary to type 2 diabetes

Aim

It’s been reported that pro-inflammatory cytokines are elevated in patients with diabetic retinopathy (DR); this may contribute to the pathophysiology of the disease. The aim of this study is to measure the concentration of various inflammatory cytokines from the main CD4+ T helper inflammatory responses in blood serum from Mexican patients with DR in different stages using cytometric bead array (CBA) technology and correlate them with the presence and severity of DR in order to find possible DR biomarkers that serve as diagnostic or therapeutic predictors.

Methods

64 subjects were included in the study, 16 in the control group, 16 in the type 2 diabetes mellitus no DR (NDR) group, 16 in the non-proliferative DR (NPDR) group and 16 in the proliferative DR (PDR) group. Cytokine concentrations of interleukin (IL) 1ß, IL‐2, IL‐4, IL‐6, IL‐8, IL‐10, IL‐12, IL‐17A, tumour necrosis factor alpha (TNFα) and interferon-gamma in serum samples were measured using Human Inflammatory and TH1/TH2/TH17 CBA Kit.

Results

IL-6, IL-12, IL-17a and TNFα were significantly higher in the patients with DR compared with the control group. The PDR group showed a slightly lower concentration of serum cytokines IL-6, IL-12 and IL-17a. TNFα showed a higher concentration compared with healthy controls, NDR and NPDR subjects. We also found a positive statistical correlation between the presence and severity of DR with the clinical parameters haemoglobin A1c, body mass index and serum creatinine and the concentration of serum cytokines IL-6 and TNFα.

Conclusion

Our findings suggest that patients with diabetes and DR have a stronger chronic inflammatory profile compared with non-diabetic subjects.

NADH/NAD+ Redox Imbalance and Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a common and severe complication of diabetes mellitus. If left untreated, DKD can advance to end stage renal disease that requires either dialysis or kidney replacement. While numerous mechanisms underlie the pathogenesis of DKD, oxidative stress driven by NADH/NAD⁺ redox imbalance and mitochondrial dysfunction have been thought to be the major pathophysiological mechanism of DKD. In this review, the pathways that increase NADH generation and those that decrease NAD⁺ levels are overviewed. This is followed by discussion of the consequences of NADH/NAD⁺ redox imbalance including disruption of mitochondrial homeostasis and function. Approaches that can be applied to counteract DKD are then discussed, which include mitochondria-targeted antioxidants and mimetics of superoxide dismutase, caloric restriction, plant/herbal extracts or their isolated compounds. Finally, the review ends by pointing out that future studies are needed to dissect the role of each pathway involved in NADH-NAD⁺ metabolism so that novel strategies to restore NADH/NAD⁺ redox balance in the diabetic kidney could be designed to combat DKD.

Glycation by glyoxal leads to profound changes in the behavior of dermal fibroblasts

INTRODUCTION

Diabetes is a worldwide health problem that is associated with severe complications. Advanced Glycation End products (AGEs) such as Nε-(carboxymethyl)lysine, which result from chronic hyperglycemia, accumulate in the skin of patients with diabetes. The effect of AGEs on fibroblast functionality and their impact on wound healing are still poorly understood.

RESEARCH DESIGN AND METHODS

To investigate this, we treated cultured human fibroblasts with 0.6 mM glyoxal to induce acute glycation. The behavior of fibroblasts was analyzed by time-lapse monolayer wounding healing assay, seahorse technology and atomic force microscopy. Production of extracellular matrix was studied by transmission electronic microscopy and western blot. Lipid metabolism was investigated by staining of lipid droplets (LDs) with BODIPY 493/503.

RESULTS

We found that the proliferative and migratory capacities of the cells were greatly reduced by glycation, which could be explained by an increase in fibroblast tensile strength. Measurement of the cellular energy balance did not indicate that there was a change in the rate of oxygen consumption of the fibroblasts. Assessment of collagen I revealed that glyoxal did not influence type I collagen secretion although it did disrupt collagen I maturation and it prevented its deposition in the extracellular matrix. We noted a pronounced increase in the number of LDs after glyoxal treatment. AMPK phosphorylation was reduced by glyoxal treatment but it was not responsible for the accumulation of LDs.

CONCLUSION

Glyoxal promotes a change in fibroblast behavior in favor of lipogenic activity that could be involved in delaying wound healing.

Redox Homeostasis in Pancreatic β-Cells: From Development to Failure

Redox status is a key determinant in the fate of β-cell. These cells are not primarily detoxifying and thus do not possess extensive antioxidant defense machinery. However, they show a wide range of redox regulating proteins, such as peroxiredoxins, thioredoxins or thioredoxin reductases, etc., being functionally compartmentalized within the cells. They keep fragile redox homeostasis and serve as messengers and amplifiers of redox signaling. β-cells require proper redox signaling already in cell ontogenesis during the development of mature β-cells from their progenitors. We bring details about redox-regulated signaling pathways and transcription factors being essential for proper differentiation and maturation of functional β-cells and their proliferation and insulin expression/maturation. We briefly highlight the targets of redox signaling in the insulin secretory pathway and focus more on possible targets of extracellular redox signaling through secreted thioredoxin1 and thioredoxin reductase1. Tuned redox homeostasis can switch upon chronic pathological insults towards the dysfunction of β-cells and to glucose intolerance. These are characteristics of type 2 diabetes, which is often linked to chronic nutritional overload being nowadays a pandemic feature of lifestyle. Overcharged β-cell metabolism causes pressure on proteostasis in the endoplasmic reticulum, mainly due to increased demand on insulin synthesis, which establishes unfolded protein response and insulin misfolding along with excessive hydrogen peroxide production. This together with redox dysbalance in cytoplasm and mitochondria due to enhanced nutritional pressure impact β-cell redox homeostasis and establish prooxidative metabolism. This can further affect β-cell communication in pancreatic islets through gap junctions. In parallel, peripheral tissues losing insulin sensitivity and overall impairment of glucose tolerance and gut microbiota establish local proinflammatory signaling and later systemic metainflammation, i.e., low chronic inflammation prooxidative properties, which target β-cells leading to their dedifferentiation, dysfunction and eventually cell death.

Association of exercise participation levels with cardiometabolic health and quality of life in individuals with hepatitis C

Objective

Hepatitis C virus (HCV) infection is associated with an increased risk of cardiovascular disease (CVD) and reduced health-related quality of life (HRQoL). Although physical activity (PA)/exercise has been shown to reduce CVD risk and improve HRQoL in patients with liver disease, there is limited data in HCV. We aimed to explore the association between PA/exercise levels, CVD risk and HRQoL in patients with HCV and assess individuals’ attitudes to PA/exercise.

Design

Cross-sectional observational study recruiting consecutive patients with HCV from viral hepatitis clinics. Data were collected on CVD risk factors, anthropometry, HRQoL and the Exercise Benefits and Barriers Scale (EBBS).

Results

86 patients were recruited (71% men, 94% white, age 52±13 years); 49% of the cohort self-reported to be currently active. Although HRQoL was reduced across the cohort, patients that were regularly ‘active’ reported significantly higher HRQoL scores across Short-Form 36v2 domains compared with their inactive counterparts (p<0.05). Metabolic and cardiovascular characteristics were no different between groups stratified by PA/exercise status (p>0.05). EBBS scores were similar in the ‘active’ versus ‘inactive’ groups, however, patients categorised as ‘active’ scored significantly higher on the psychological outlook and social interaction subscales (p<0.05) than those that were ‘inactive’. There were significant associations between EBBS scores and HRQoL (p<0.05).

Conclusions

PA/exercise is associated with increased HRQoL in patients with HCV irrespective of clinical parameters. Addressing specific motivators/barriers to exercise for patients will be key to designing effective PA/exercise interventions in this patient population to ensure maximum uptake and adherence.

SARS-CoV-2 and Other Respiratory Viruses: What Does Oxidative Stress Have to Do with It?

The phenomenon of oxidative stress, characterized as an imbalance in the production of reactive oxygen species and antioxidant responses, is a well-known inflammatory mechanism and constitutes an important cellular process. The relationship of viral infections, reactive species production, oxidative stress, and the antiviral response is relevant. Therefore, the aim of this review is to report studies showing how reactive oxygen species may positively or negatively affect the pathophysiology of viral infection. We focus on known respiratory viral infections, especially severe acute respiratory syndrome coronaviruses (SARS-CoVs), in an attempt to provide important information on the challenges posed by the current COVID-19 pandemic. Because antiviral therapies for severe acute respiratory syndrome coronaviruses (e.g., SARS-CoV-2) are rare, knowledge about relevant antioxidant compounds and oxidative pathways may be important for understanding viral pathogenesis and identifying possible therapeutic targets.

Reactive Oxygen Species: Drivers of Physiological and Pathological Processes

Since the Great Oxidation Event, about 2.4 billion years ago, the Earth is immersed in an oxidizing atmosphere. Thus, it has been proposed that excess oxygen, originally a waste product of photosynthetic cyanobacteria, induced oxidative stress and the production of reactive oxygen species (ROS), which have since acted as fundamental drivers of biologic evolution and eukaryogenesis. Indeed, throughout an organism’s lifespan, ROS affect directly (as mutagens) or indirectly (as messengers and regulators) all structural and functional components of cells, and many aspects of cell biology. Whether left unchecked by protective antioxidant systems, excess ROS not only cause genomic mutations but also induce irreversible oxidative modification of proteins (protein oxidation and peroxidation), lipids and glycans (advanced lipoxidation and glycation end products), impairing their function and promoting disease or cell death. Conversely, low-level local ROS play an important role both as redox-signaling molecules in a wide spectrum of pathways involved in the maintenance of cellular homeostasis (MAPK/ERK, PTK/PTP, PI3K-AKT-mTOR), and regulating key transcription factors (NFκB/IκB, Nrf2/KEAP1, AP-1, p53, HIF-1). Consequently, ROS can shape a variety of cellular functions, including proliferation, differentiation, migration and apoptosis. In this review, we will give a brief overview of the relevance of ROS in both physiological and pathological processes, particularly inflammation and aging. In-depth knowledge of the molecular mechanisms of ROS actuation and their influence under steady-state and stressful conditions will pave the way for the development of novel therapeutic interventions. This will mitigate the harmful outcomes of ROS in the onset and progression of a variety of chronic inflammatory and age-related diseases.

Anaphylaxis following enteral exposure to Chlorella vulgaris

We present a case of a 75-year-old man who was admitted to an Australian tertiary emergency department with severe hypotension, wheeze, widespread urticarial rash and diarrhoea. On arrival to the emergency department following initial resuscitation by ambulance staff, he was admitted to the intensive care unit with a presumptive diagnosis of gastroenteritis. This diagnosis was later revised following the availability of tryptase levels and clarification of his presenting circumstances, which established a clear temporal relationship between his anaphylactoid symptoms and the oral ingestion of Chlorella vulgaris supplements. While there are a few case studies describing allergic/anaphylactic reactions to several other species of Chlorella, this appears to be the first reported case of anaphylaxis to C. vulgaris.

Study protocol for SFX-01 after subarachnoid haemorrhage (SAS): a multicentre randomised double-blinded, placebo controlled trial

INTRODUCTION

Subarachnoid haemorrhage (SAH) from a ruptured cerebral aneurysm carries high morbidity and mortality. Despite huge advances in techniques to secure the aneurysm, there has been little progress in the treatment of the deleterious effects of the haemorrhage.Sulforaphane is an Nrf2 inducer with anti-oxidant and anti-inflammatory properties. It has been shown to improve clinical outcome in experimental models of SAH, but is unstable. SFX-01 (Evgen Pharma) is a novel composition comprised of synthetic sulforaphane stabilised within an α-cyclodextrin complex. On ingestion, the complex releases sulforaphane making SFX-01 an ideal vehicle for delivery of sulforaphane.

METHODS AND ANALYSIS

The objective of the study is to assess the safety, pharmacokinetics and efficacy of SFX-01. This is a prospective, multicentre, randomised, double-blind placebo-controlled trial in patients aged 18-80 years with aneurysmal subarachnoid haemorrhage in the previous 48 hours. 90 patients will be randomised to receive SFX-01 (300 mg) or placebo two times per day for up to 28 days.Safety will be assessed using blood tests and adverse event reporting.Pharmacokinetics will be assessed based on paired blood and cerebrospinal fluid (CSF) sulforaphane levels on day 7. A subgroup will have hourly samples taken during 6 hours post-dosing on days 1 and 7. Pharmacodynamics will be assessed by haptoglobin and malondialdehyde levels, and maximum flow velocity of middle cerebral artery will be measured by transcranial Doppler ultrasound.Clinical outcomes will be assessed at days 28, 90 and 180 with modified Rankin Scale, Glasgow Outcome Score, SAH Outcome Tool, Short Form-36, Brain Injury Community Rehabilitation Outcome Scales and Check List for Cognitive and Emotional consequences following stroke. MRI at 6 months including quantitative susceptibility mapping and volumetric T1 will measure iron deposition and cortical volume.Safety, CSF sulforaphane concentration and middle cerebral artery flow velocity will be primary outcomes and all others secondary.

ETHICS AND DISSEMINATION

Ethical approval was obtained from South Central Hampshire A committee. Outcomes of the trial will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02614742.

GPCRs, G Proteins, and Their Impact on β-cell Function

Glucose-induced (physiological) insulin secretion from the islet β-cell involves interplay between cationic (i.e., changes in intracellular calcium) and metabolic (i.e., generation of hydrophobic and hydrophilic second messengers) events. A large body of evidence affirms support for novel regulation, by G proteins, of specific intracellular signaling events, including actin cytoskeletal remodeling, transport of insulin-containing granules to the plasma membrane for fusion, and secretion of insulin into the circulation. This article highlights the following aspects of GPCR-G protein biology of the islet. First, it overviews our current understanding of the identity of a wide variety of G protein regulators and their modulatory roles in GPCR-G protein-effector coupling, which is requisite for optimal β-cell function under physiological conditions. Second, it describes evidence in support of novel, noncanonical, GPCR-independent mechanisms of activation of G proteins in the islet. Third, it highlights the evidence indicating that abnormalities in G protein function lead to islet β-cell dysregulation and demise under the duress of metabolic stress and diabetes. Fourth, it summarizes observations of potential beneficial effects of GPCR agonists in preventing/halting metabolic defects in the islet β-cell under various pathological conditions (e.g., metabolic stress and inflammation). Lastly, it identifies knowledge gaps and potential avenues for future research in this evolving field of translational islet biology. Published 2020. Compr Physiol 10:453-490, 2020.

Use of S1QELs and S3QELs to link mitochondrial sites of superoxide and hydrogen peroxide generation to physiological and pathological outcomes

Changes in mitochondrial superoxide and hydrogen peroxide production may contribute to various pathologies, and even aging, given that over time and in certain conditions, they damage macromolecules and disrupt normal redox signalling. Mitochondria-targeted antioxidants such as mitoQ, mitoVitE, and mitoTEMPO have opened up the study of the importance of altered mitochondrial matrix superoxide/hydrogen peroxide in disease. However, the use of such tools has caveats and they are unable to distinguish precise sites of production within the reactions of substrate oxidation and the electron transport chain. S1QELs are specific small-molecule Suppressors of site IQElectron Leak and S3QELs are specific small-molecule Suppressors of site IIIQoElectron Leak; they prevent superoxide/hydrogen production at specific sites without affecting electron transport or oxidative phosphorylation. We discuss the benefits of using S1QELs and S3QELs as opposed to mitochondria-targeted antioxidants, mitochondrial poisons, and genetic manipulation. We summarise pathologies in which site IQ in mitochondrial complex I and site IIIQo in mitochondrial complex III have been implicated using S1QELs and S3QELs.