Changes in Myocardial Metabolism Preceding Sudden Cardiac Death

Heart disease is widely recognized as a major cause of death worldwide and is the leading cause of mortality in the United States. Centuries of research have focused on defining mechanistic alterations that drive cardiac pathogenesis, yet sudden cardiac death (SCD) remains a common unpredictable event that claims lives in every age group. The heart supplies blood to all tissues while maintaining a constant electrical and hormonal feedback communication with other parts of the body. As such, recent research has focused on understanding how myocardial electrical and structural properties are altered by cardiac metabolism and the various signaling pathways associated with it. The importance of cardiac metabolism in maintaining myocardial function, or lack thereof, is exemplified by shifts in cardiac substrate preference during normal development and various pathological conditions. For instance, a shift from fatty acid (FA) oxidation to oxygen-sparing glycolytic energy production has been reported in many types of cardiac pathologies. Compounded by an uncoupling of glycolysis and glucose oxidation this leads to accumulation of undesirable levels of intermediate metabolites. The resulting accumulation of intermediary metabolites impacts cardiac mitochondrial function and dysregulates metabolic pathways through several mechanisms, which will be reviewed here. Importantly, reversal of metabolic maladaptation has been shown to elicit positive therapeutic effects, limiting cardiac remodeling and at least partially restoring contractile efficiency. Therein, the underlying metabolic adaptations in an array of pathological conditions as well as recently discovered downstream effects of various substrate utilization provide guidance for future therapeutic targeting. Here, we will review recent data on alterations in substrate utilization in the healthy and diseased heart, metabolic pathways governing cardiac pathogenesis, mitochondrial function in the diseased myocardium, and potential metabolism-based therapeutic interventions in disease.

The Use of Metformin to Increase the Human Healthspan

Metformin is a safe, effective and useful drug for glucose management in patients with diabetes. However in recent years, more attention has been paid to the possibility of using metformin as an anti-aging drug. It was shown to significantly increase the lifespan in some model organisms and delay the onset of age-associated declines. The current review summarizes advances in clinical research on the potential role of metformin in the field of lifespan and healthspan extension. Growing amounts of evidence from clinical trials suggest that metformin can effectively reduce the risk of many age-related diseases and conditions, including cardiometabolic disorders, neurodegeneration, chronic inflammation and frailty. Metformin also holds promise as a drug that could be repurposed for chemoprevention or adjuvant therapy for certain types of cancer. Moreover, metformin induces autophagy by activation of AMPK and can thus be potentially used to promote heathspan by hormesis-like mechanisms. Although long-term intake of metformin is associated with low risk of adverse events, well-designed clinical trials are still required to uncover the potential use of this drug as a geroprotector.

Metformin pretreatment suppresses alterations to the articular cartilage ultrastructure and knee joint tissue damage secondary to type 2 diabetes mellitus in rats

Osteoarthritis (OA) secondary to diabetes affects millions of people worldwide and can lead to disability. The protective effect of metformin pretreatment against alterations to the articular cartilage ultrastructure induced by type 2 diabetes mellitus (T2DM) associated with the inhibition of oxidative stress and inflammation has not been investigated before. Therefore, we induced T2DM in rats (the model group) using high carbohydrate and fat diet and a single injection of streptozotocin (50 mg/kg body weight). The protective group of rats started metformin (200 mg/kg body weight) treatment 14 days before diabetic induction and continued on metformin until the end of the experiment at week 12. Harvested tissues obtained from knee joints were prepared for staining with hematoxylin and eosin (H&E), safranin o staining, and electron microscopy. Histology images showed that OA was developed in the T2DM rats as demonstrated by a substantial damage to the articular cartilage and profound chondrocyte and territorial matrix ultrastructural alterations, which were partially protected by metformin. In addition, metformin significantly (p < .05) reduced hyperglycemia, glycated hemoglobin (HbA1 c), malondialdehyde (MDA), high sensitivity C-reactive protein (hs-CRP), and interleukin-6 blood levels induced by diabetes. Furthermore, a significant (p ≤ 0.015) correlation between either OA cartilage grade score or the thickness of the articular cartilage and the blood levels of HbA1 c, hs-CRP, MDA, superoxide dismutase (SOD) were observed. These findings demonstrate effective protection of the articular cartilage by metformin against damage induced secondary to T2DM in rats, possibly due to the inhibition of hyperglycemia and biomarkers of oxidative stress and inflammation.

The Role of AMPK Activation for Cardioprotection in Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a commonly used chemotherapeutic agent for the treatment of a range of cancers, but despite its success in improving cancer survival rates, doxorubicin is cardiotoxic and can lead to congestive heart failure. Therapeutic options for this patient group are limited to standard heart failure medications with the only drug specific for doxorubicin cardiotoxicity to reach FDA approval being dexrazoxane, an iron-chelating agent targeting oxidative stress. However, dexrazoxane has failed to live up to its expectations from preclinical studies while also bringing up concerns about its safety. Despite decades of research, the molecular mechanisms of doxorubicin cardiotoxicity are still poorly understood and oxidative stress is no longer considered to be the sole evil. Mitochondrial impairment, increased apoptosis, dysregulated autophagy and increased fibrosis have also been shown to be crucial players in doxorubicin cardiotoxicity. These cellular processes are all linked by one highly conserved intracellular kinase: adenosine monophosphate-activated protein kinase (AMPK). AMPK regulates mitochondrial biogenesis via PGC1α signalling, increases oxidative mitochondrial metabolism, decreases apoptosis through inhibition of mTOR signalling, increases autophagy through ULK1 and decreases fibrosis through inhibition of TGFβ signalling. AMPK therefore sits at the control point of many mechanisms shown to be involved in doxorubicin cardiotoxicity and cardiac AMPK signalling itself has been shown to be impaired by doxorubicin. In this review, we introduce different agents known to activate AMPK (metformin, statins, resveratrol, thiazolidinediones, AICAR, specific AMPK activators) as well as exercise and dietary restriction, and we discuss the existing evidence for their potential role in cardioprotection from doxorubicin cardiotoxicity.

Atorvastatin protects against contrast-induced acute kidney injury via upregulation of endogenous hydrogen sulfide

Background

Contrast-induced acute kidney injury (CIAKI) is the third leading cause of acute renal failure in hospitalized patients. This study was aimed to investigate whether atorvastatin could upregulate the expression of hydrogen sulfide (H₂S) and hence protect against CIAKI.

Methods

We treated male rats and NRK-52E cells by iopromide to establish in vivo and in vitro models of CIAKI. Pretreatment with atorvastatin was given in CIAKI rats to investigate its effect on CIAKI. We collected serum and urine samples to detect renal function. We obtained kidney tissue for histological analysis and detection of protein concentration. We tested the serum concentration of H₂S and renal expression of two H₂S synthetases [cystathionine γ-lyase (CSE) and cystathionine-β synthase (CBS)]. NaHS was pretreated in NRK-52E cells to testify its underlying effect on contrast-induced injury.

Results

Atorvastatin significantly ameliorated renal dysfunction and morphological changes in CIAKI rats, as well as inflammation, apoptosis, and excessive oxidative stress. Atorvastatin also markedly increased the serum concentration of H₂S and renal expression of CSE and CBS. Moreover, pretreatment with NaHS in NRK-52E cells considerably attenuated contrast-induced cell death and inflammation.

Conclusion

Atorvastatin protects against CIAKI via upregulation of endogenous hydrogen sulfide.

Metformin and heart failure-related outcomes in patients with or without diabetes: a systematic review of randomized controlled trials

Metformin is considered a safe anti-hyperglycemic drug for patients with type 2 diabetes (T2D); however, information on its impact on heart failure-related outcomes remains inconclusive. The current systematic review explored evidence from randomized clinical trials (RCTs) reporting on the impact of metformin in modulating heart failure-related markers in patients with or without T2D. Electronic databases such as MEDLINE, Cochrane Library, and EMBASE were searched for eligible studies. Included studies were those assessing the use of metformin as an intervention, and also containing the comparison group on placebo, and all articles had to report on measurable heart failure-related indices in individuals with or without T2D. The modified Downs and Black checklist was used to evaluate the risk of bias. Overall, nine studies met the inclusion criteria, enrolling a total of 2486 patients. Although summarized evidence showed that metformin did not affect left ventricular function, this antidiabetic drug could improve myocardial oxygen consumption concomitant to reducing prominent markers of heart failure such as n-terminal pro-brain natriuretic peptide and low-density lipoprotein levels, inconsistently between diabetic and nondiabetic patients. Effective modulation of some heart failure-related outcomes with metformin treatment was related to its beneficial effects in ameliorating insulin resistance and blocking pro-inflammatory markers such as the aging-associated cytokine CCL11 (C-C motif chemokine ligand 11). Overall, although such beneficial effects were observed with metformin treatment, additional RCTs are necessary to improve our understanding on its modulatory effects on heart failure-related outcomes especially in diabetic patients.

The protective effect of metformin on mitochondrial dysfunction and endoplasmic reticulum stress in diabetic mice brain

Diabetes is a metabolic disorder associated with mitochondrial (mt) dysfunction and oxidative stress. The molecular mechanisms involved in diabetes-associated neurological complications remain elusive. This study aims to investigate the protective effect of metformin (MF) on regulatory networks and integrated stress responses in brain tissue of Streptozotocin (STZ)-induced diabetic mice. STZ-induced diabetic mice were treated with MF (20 mg/kg BW), and whole brain tissue was harvested for further analysis. Protein carbonylation was measured as a marker of neuronal oxidative stress. Protein expression of mt chaperones, maintenance proteins, and regulators of the unfolded protein response (UPR) were measured by Western blot. Transcript levels of antioxidant enzyme GSTA4; mt biogenesis markers, ER stress regulators, and miR-132 and miR-148a were analysed using qPCR. The results showed that MF efficiently reduced protein carbonylation and oxidation. Mt function was improved by MF-treatment through upregulation of chaperone proteins (HSP60, HSP70 and LonP1). MF elicits the UPR to attenuate ER stress through a miR-132 repression mechanism. Additionally, MF was found to elevate deacetylases- Sirt1, Sirt3; and mt biogenesis marker PGC-1α through miR-148a repression. This is the first study to demonstrate the epigenetic regulation of mt maintenance by MF in diabetic C57BL/6 mouse whole brain tissue. We thus conclude that MF, beyond its anti-hyperglycaemic role, mediates neuroprotection through epigenomic and integrated stress responses in diabetic mice.

The Gut Microbiota and Its Implication in the Development of Atherosclerosis and Related Cardiovascular Diseases

The importance of gut microbiota in health and disease is being highlighted by numerous research groups worldwide. Atherosclerosis, the leading cause of heart disease and stroke, is responsible for about 50% of all cardiovascular deaths. Recently, gut dysbiosis has been identified as a remarkable factor to be considered in the pathogenesis of cardiovascular diseases (CVDs). In this review, we briefly discuss how external factors such as dietary and physical activity habits influence host-microbiota and atherogenesis, the potential mechanisms of the influence of gut microbiota in host blood pressure and the alterations in the prevalence of those bacterial genera affecting vascular tone and the development of hypertension. We will also be examining the microbiota as a therapeutic target in the prevention of CVDs and the beneficial mechanisms of probiotic administration related to cardiovascular risks. All these new insights might lead to novel analysis and CVD therapeutics based on the microbiota.

Hydrogen Sulfide as a Potential Alternative for the Treatment of Myocardial Fibrosis

Harmful, stressful conditions or events in the cardiovascular system result in cellular damage, inflammation, and fibrosis. Currently, there is no targeted therapy for myocardial fibrosis, which is highly associated with a large number of cardiovascular diseases and can lead to fatal heart failure. Hydrogen sulfide (H₂S) is an endogenous gasotransmitter similar to nitric oxide and carbon monoxide. H₂S is involved in the suppression of oxidative stress, inflammation, and cellular death in the cardiovascular system. The level of H₂S in the body can be boosted by stimulating its synthesis or supplying it exogenously with a simple H₂S donor with a rapid- or slow-releasing mode, an organosulfur compound, or a hybrid with known drugs (e.g., aspirin). Hypertension, myocardial infarction, and inflammation are exaggerated when H₂S is reduced. In addition, the exogenous delivery of H₂S mitigates myocardial fibrosis caused by various pathological conditions, such as a myocardial infarct, hypertension, diabetes, or excessive β-adrenergic stimulation, via its involvement in a variety of signaling pathways. Numerous experimental findings suggest that H₂S may work as a potential alternative for the management of myocardial fibrosis. In this review, the antifibrosis role of H₂S is briefly addressed in order to gain insight into the development of novel strategies for the treatment of myocardial fibrosis.

Metformin and Its Benefits for Various Diseases

Metformin is a widely used biguanide drug due to its safety and low cost. It has been used for over 60 years to treat type 2 diabetes at the early stages because of its outstanding ability to decrease plasma glucose levels. Over time, different uses of metformin were discovered, and the benefits of metformin for various diseases and even aging were verified. These diseases include cancers (e.g., breast cancer, endometrial cancer, bone cancer, colorectal cancer, and melanoma), obesity, liver diseases, cardiovascular disease, and renal diseases. Metformin exerts different effects through different signaling pathways. However, the underlying mechanisms of these different benefits remain to be elucidated. The aim of this review is to provide a brief summary of the benefits of metformin and to discuss the possible underlying mechanisms.

Detection, identification, and quantification of oxidative protein modifications

Exposure of biological molecules to oxidants is inevitable and therefore commonplace. Oxidative stress in cells arises from both external agents and endogenous processes that generate reactive species, either purposely (e.g. during pathogen killing or enzymatic reactions) or accidentally (e.g. exposure to radiation, pollutants, drugs, or chemicals). As proteins are highly abundant and react rapidly with many oxidants, they are highly susceptible to, and major targets of, oxidative damage. This can result in changes to protein structure, function, and turnover and to loss or (occasional) gain of activity. Accumulation of oxidatively-modified proteins, due to either increased generation or decreased removal, has been associated with both aging and multiple diseases. Different oxidants generate a broad, and sometimes characteristic, spectrum of post-translational modifications. The kinetics (rates) of damage formation also vary dramatically. There is a pressing need for reliable and robust methods that can detect, identify, and quantify the products formed on amino acids, peptides, and proteins, especially in complex systems. This review summarizes several advances in our understanding of this complex chemistry and highlights methods that are available to detect oxidative modifications-at the amino acid, peptide, or protein level-and their nature, quantity, and position within a peptide sequence. Although considerable progress has been made in the development and application of new techniques, it is clear that further development is required to fully assess the relative importance of protein oxidation and to determine whether an oxidation is a cause, or merely a consequence, of injurious processes.

Thyroxine Alleviates Energy Failure, Prevents Myocardial Cell Apoptosis, and Protects against Doxorubicin-Induced Cardiac Injury and Cardiac Dysfunction via the LKB1/AMPK/mTOR Axis in Mice

Background

Previous studies have demonstrated that energy failure is closely associated with cardiac injury. Doxorubicin (DOX) is a commonly used clinical chemotherapy drug that can mediate cardiac injury through a variety of mechanisms. Thyroxine is well known to play a critical role in energy generation; thus, this study is aimed at investigating whether thyroxine can attenuate DOX-induced cardiac injury by regulating energy generation.

Methods

First, the effect of DOX on adenosine diphosphate (ADP) and adenosine triphosphate (ATP) ratios in mice was assessed. In addition, thyroxine was given to mice before they were treated with DOX to investigate the effects of thyroxine on DOX-induced cardiac injury. Furthermore, to determine whether the liver kinase b1 (LKB1)/adenosine 5′-monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) axis mediated the effect of thyroxine on DOX-induced cardiac injury, thyroxine was given to DOX-treated LKB1 knockout (KO) mice.

Results

DOX treatment time- and dose-dependently increased the ADP/ATP ratio. Thyroxine treatment also reduced lactate dehydrogenase (LDH) and creatine kinase myocardial band (CK-MB) levels in both serum and heart tissue and alleviated cardiac dysfunction in DOX-treated mice. Furthermore, thyroxine reversed DOX-induced reductions in LKB1 and AMPK phosphorylation; mitochondrial complex I, III, and IV activity; and mitochondrial swelling and reversed DOX-induced increases in mTOR pathway phosphorylation and myocardial cell apoptosis. These effects of thyroxine on DOX-treated mice were significantly attenuated by LKB1 KO.

Conclusions

Thyroxine alleviates energy failure, reduces myocardial cell apoptosis, and protects against DOX-induced cardiac injury via the LKB1/AMPK/mTOR axis in mice. Thyroxine may be a new agent for the clinical prevention of cardiac injury in tumor patients undergoing chemotherapy with DOX.

Role of Metformin on Osteoblast Differentiation in Type 2 Diabetes

Metformin, an effective hypoglycemic, can modulate different points of malignant mass, polycystic ovary syndrome (PCOS), cardiovascular diseases, tuberculosis, and nerve regeneration. Recently, the effect of metformin on bone metabolism has been analyzed. Metformin relies on organic cation transporters (OCT1), a polyspecific cell membrane of the solute carrier 22A (SLC22A) gene family, to facilitate its intracellular uptake and action on complex I of the respiratory chain of mitochondria. These changes activate the cellular energy sensor AMP-activated protein kinase (AMPK). Thus, the increased cellular AMP/ATP ratio causes a dramatic and progressive activation of insulin and lysosomes, resulting in a decrease in intracellular glucose level, which promotes osteoblast proliferation and differentiation. AMPK also phosphorylates runt-related transcription factor 2 (Runx2) at S118, the lineage-specific transcriptional regulators, to promote osteogenesis. Metformin phosphorylates extracellular signal-regulated kinase (ERK), stimulates endothelial and inducible nitric oxide synthases (e/iNOS), inhibits the GSK3β/Wnt/β-catenin pathway, and promotes osteogenic differentiation of osteoblasts. The effect of metformin on hyperglycemia decreases intracellular reactive oxygen species (ROS) and advanced glycation end-products (AGEs) in collagen, and reduced serum levels of insulin-like growth factors (IGF-1) were beneficial for bone formation. Metformin has a certain effect on microangiopathy and anti-inflammation, which can induce osteoporosis, activate the activity of osteoclasts, and inhibit osteoblast activity, and has demonstrated extensive alteration in bone and mineral metabolism. The aim of this review was to elucidate the mechanisms of metformin on osteoblasts in insulin-deficient diabetes.

Immunomodulatory Effects of Vitamin D in Pregnancy and Beyond

In addition to its role in calcium homeostasis and bone formation, a modulatory role of the active form of vitamin D on cells of the immune system, particularly T lymphocytes, has been described. The effects of vitamin D on the production and action of several cytokines has been intensively investigated in recent years. In this connection, deficiency of vitamin D has been associated with several autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), Hashimoto Thyroiditis (HT), and multiple sclerosis (MS). In a successful pregnancy, the maternal immune response needs to adapt to accommodate the semiallogeneic fetus. Disturbances in maternal tolerance are implicated in infertility and pregnancy complications such as miscarriages (RM) and preeclampsia (PE). It is well-known that a subset of T lymphocytes, regulatory T cells (Tregs) exhibit potent suppressive activity, and have a crucial role in curtailing the destructive response of the immune system during pregnancy, and preventing autoimmune diseases. Interestingly, vitamin D deficiency is common in pregnant women, despite the widespread use of prenatal vitamins, and adverse pregnancy outcomes such as RM, PE, intrauterine growth restriction have been linked to hypovitaminosis D during pregnancy. Research has shown that autoimmune diseases have a significant prevalence within the female population, and women with autoimmune disorders are at higher risk for adverse pregnancy outcomes. Provocatively, dysregulation of T cells plays a crucial role in the pathogenesis of autoimmunity, and adverse pregnancy outcomes where these pathologies are also associated with vitamin D deficiency. This article reviews the immunomodulatory role of vitamin D in autoimmune diseases and pregnancy. In particular, we will describe the role of vitamin D from conception until delivery, including the health of the offspring. This review highlights an observational study where hypovitaminosis D was correlated with decreased fertility, increased disease activity, placental insufficiency, and preeclampsia in women with APS.

Sex and Body Mass Index Modify the Association Between Leptin and Sodium Excretion: A Cross-sectional Study in an African Population

BACKGROUND

Renal sodium handling could be a potential mediator linking adipokines to hypertension. The aim of the study was to assess the relationship of leptin with urinary sodium excretion and proximal sodium reabsorption in humans.

METHODS

This cross-sectional study was conducted on participants of hypertensive families from the Seychelles Island. A split urine (daytime and nighttime) collection and plasma leptin were measured. Endogenous lithium clearance was used to assess proximal sodium reabsorption. Mixed multiple linear regression tests adjusted for confounding factors were used.

RESULTS

Three hundred and sixty-five participants (57% women) were included in this analysis. Leptin and adiponectin were higher in women (P < 0.001). Leptin was associated positively with daytime (coefficient [c]: 0.16, standard deviation (SD): 0.03, P < 0.001), nighttime urinary sodium excretion (c: 0.17, SD: 0.04), P < 0.01), daytime lithium clearance (c: 0.40, SD: 0.08, P < 0.001), and nighttime lithium clearance (c: 0.39, SD: 0.10, P < 0.001) after adjusting for sex. The association was lost or mitigated only when BMI was introduced in the model. When BMI was categorized in normal vs. overweight participant, leptin was associated with daytime and nighttime sodium excretion rates (c: 0.14, SD: 0.05, P = 0.011 and c: 0.22, SD: 0.07, P = 0.002, respectively) only in overweight participants.

CONCLUSION

Leptin is associated positively with daytime and nighttime sodium excretion and lithium clearance suggesting a natriuretic rather than a sodium retaining effect of leptin. Sex and body mass index (BMI) are major confounders in this association. These results highlight the importance of sex and obesity in our understanding of the relationships between leptin, blood pressure, and renal sodium handling.

Acute effects of different doses of malathion on the rat liver

Aim of the study

Our study was designed to evaluate the acute effects of malathion on rat liver tissues.

Material and methods

The animals were divided into 4 groups of 6 animals/each. Group 1 (control group) received corn oil, while groups 2, 3, and 4 were given malathion dissolved in corn oil at a dose of 100, 200 and 400 mg/kg, respectively. 24 hours after malathion administration, animals were sacrificed and liver tissues were collected. The liver tissues were then analysed biochemically and histopathologically.

Results

Butyrylcholinesterase levels in groups 2, 3 and 4 were significantly lower than that of group 1. Total oxidant status and tumour necrosis factor alpha level were significantly increased in group 4 compared to group 1. Catalase activities of groups 3 and 4 were significantly higher than that of group 1. Arylesterase activity was significantly decreased in groups 3 and 4 compared to group 1. In groups 3 and 4, some vacuoles in hepatocytes were revealed and hydropic degeneration was observed in group 4.

Conclusions

Acute administrations of malathion results in hepatotoxicity in a dose-dependent manner.

Glucocrinology of Modern Sulfonylureas: Clinical Evidence and Practice-Based Opinion from an International Expert Group

AIM

The primary objective of this document is to develop practice-based expert group opinion on certain important but less discussed endocrine and metabolic effects of modern sulfonylureas (SUs) and their usage in the management of diabetes mellitus (DM).

BACKGROUND

Modern SUs may be considered a panacea in DM care with their beneficial extra-pancreatic, pleiotropic, and cardiovascular effects. Safe glycemic control with SUs could be achieved with appropriate patient selection, drug and dosage selection, and patient empowerment. Additionally, sulfonylureas also exhibit certain endocrine and metabolic effects, which could be considered beneficial in the management of DM. In this regard, a group of international clinical experts discussed the less known beneficial aspects of SUs and safe and smart prescription of modern SUs in DM care.

RESULTS

The concept of glucocrinology or the relationship of glycemia with the endocrine system was emphasized during the meetings. Clinical experts arrived at a consensus for the usage of modern SUs in the presence of other endocrine dysfunction and the impact of these drugs on endocrine health. The beneficial pleiotropic and cardiovascular effects of modern SUs were also discussed. The key discussion points were considered to develop clinical expert opinions for the use of modern SUs in persons with DM. Clinical expert opinions were developed for indications, pleiotropic benefits, cardiovascular outcomes, adherence, and safe use of modern SUs.

CONCLUSIONS

Appropriate clinical judgement coupled with a patient-centered approach is crucial to achieve the best outcome in persons with DM. Owing to their safety, efficacy, extra-pancreatic benefits including effects on endocrine and metabolic aspects, and low cost of therapy, modern SUs could be considered as drugs/agents of choice for the treatment of diabetes.

FUNDING

Sanofi India.

Pericoronary fat inflammation and Major Adverse Cardiac Events (MACE) in prediabetic patients with acute myocardial infarction: effects of metformin

BACKGROUND/OBJECTIVES

Pericoronary adipose tissue inflammation might lead to the development and destabilization of coronary plaques in prediabetic patients. Here, we evaluated inflammation and leptin to adiponectin ratio in pericoronary fat from patients subjected to coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI). Furthermore, we compared the 12-month prognosis of prediabetic patients compared to normoglycemic patients (NG). Finally, the effect of metformin therapy on pericoronary fat inflammation and 12-months prognosis in AMI-prediabetic patients was also evaluated.

METHODS

An observational prospective study was conducted on patients with first AMI referred for CABG. Participants were divided in prediabetic and NG-patients. Prediabetic patients were divided in two groups; never-metformin-users and current-metformin-users receiving metformin therapy for almost 6 months before CABG. During the by-pass procedure on epicardial coronary portion, the pericoronary fat was removed from the surrounding stenosis area. The primary endpoints were the assessments of Major-Adverse-Cardiac-Events (MACE) at 12-month follow-up. Moreover, inflammatory tone was evaluated by measuring pericoronary fat levels of tumor necrosis factor-α (TNF-α), sirtuin 6 (SIRT6), and leptin to adiponectin ratio. Finally, inflammatory tone was correlated to the MACE during the 12-months follow-up.

RESULTS

The MACE was 9.1% in all prediabetic patients and 3% in NG-patients. In prediabetic patients, current-metformin-users presented a significantly lower rate of MACE compared to prediabetic patients never-metformin-users. In addition, prediabetic patients showed higher inflammatory tone and leptin to adiponectin ratio in pericoronary fat compared to NG-patients (P < 0.001). Prediabetic never-metformin-users showed higher inflammatory tone and leptin to adiponectin ratio in pericoronary fat compared to current-metformin-users (P < 0.001). Remarkably, inflammatory tone and leptin to adiponectin ratio was significantly related to the MACE during the 12-months follow-up.

CONCLUSION

Prediabetes increase inflammatory burden in pericoronary adipose tissue. Metformin by reducing inflammatory tone and leptin to adiponectin ratio in pericoronary fat may improve prognosis in prediabetic patients with AMI. Trial registration Clinical Trial NCT03360981, Retrospectively Registered 7 January 2018.

Metformin Use and Clinical Outcomes Among Patients With Diabetes Mellitus With or Without Heart Failure or Kidney Dysfunction

Background:

Metformin is first-line therapy for type 2 diabetes mellitus, although its effects on the cardiovascular system are unproved.

Methods:

In this post hoc analysis, patients in SAVOR-TIMI 53 (Saxagliptin and Cardiovascular Outcomes in Patients With Type 2 Diabetes Mellitus) with baseline biomarker samples (n=12 156) were classified as ever versus never taking metformin during the trial period. Associations between metformin exposure and outcomes were estimated with inverse probability of treatment weighting Cox modeling for the composite end point of cardiovascular death, myocardial infarction, or ischemic stroke, as well as cardiovascular death and all-cause mortality, with biomarkers included as covariates. Additional sensitivity analyses included propensity score matching and Cox multivariable models.

Results:

Of the 12 156 patients with baseline biomarker samples, 8971 (74%) had metformin exposure, 1611 (13%) had prior heart failure, and 1332 (11%) had at least moderate chronic kidney disease (estimated glomerular filtration rate ≤45 mL·min −1 ·1.73 m −2 ). Metformin use was associated with no difference in risk for the composite end point (hazard ratio for inverse probability of treatment weighting, 0.92 [95% CI, 0.76–1.11]) but lower risk of all-cause mortality (hazard ratio for inverse probability of treatment weighting, 0.75 [95% CI, 0.59–0.95]). There was no significant relationship between metformin use and these end points in patients with prior heart failure or moderate to severe chronic kidney disease.

Conclusions:

In a cohort of 12 156 patients with type 2 diabetes mellitus and high cardiovascular risk, metformin use was associated with lower rates of all-cause mortality, including after adjustment for clinical variables and biomarkers, but not lower rates of the composite end point of cardiovascular death, myocardial infarction, or ischemic stroke. This association was most apparent in patients without prior heart failure or moderate to severe chronic kidney disease.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01107886.

Metformin suppresses aortic ultrastrucural damage and hypertension induced by diabetes: a potential role of advanced glycation end products

Cardiovascular disease secondary to diabetes represents a significant challenge to the health community. The advanced glycation end products (AGEs) play an important role in diabetes-mediated vascular injury. We tested whether metformin can suppress aortic AGEs production and protect against aortic injuries (aortopathy) and hypertension in streptozotocin-induced type 2 diabetes mellitus (T2DM) animal model. T2DM was induced in rats two weeks after being fed on a high carbohydrate and fat diet (HCFD), and continued on a HCFD until being sacrificed at week 12 (model group). The protective group was put on metformin two weeks before diabetic induction and continued on metformin and HCFD until the end of the experiment, at week 12. Using electron microscopy examinations, we observed in the model group substantial damage to the ultrastructure of aortic endothelial and vascular smooth muscle layers as demonstrated by markedly distorted vacuolated endothelial and vascular smooth muscle cells with pyknotic nuclei detached from the underlying basement membrane, which were protected by metformin. Also, metformin significantly (p < .05) decreased both systolic and diastolic blood pressure, aortic levels of AGEs, and blood levels of oxidative stress and inflammatory biomarkers. We conclude that metformin protects against T2DM-induced aortopathy and hypertension, possibly via the inhibition of AGEs, inflammation, and oxidative stress.

Crosstalk Between Adipokines and Paraoxonase 1: A New Potential Axis Linking Oxidative Stress and Inflammation

Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated protein that endows its carrier with (lipo-)lactonase-dependent antioxidative features. Low levels of PON1 activity have been observed in association with obesity, a major risk factor for cardiovascular disease (CVD). Considering the well-recognized atheroprotective role of PON1, exogenous/endogenous factors that might modulate its levels/activity are raising great interest. Since adipokines represent a molecular link between obesity and CVD, we here explored the possible impact of these substances on PON1 activity/expression. The levels of interleukin (IL)-6, IL-8, tumor necrosis factor alpha, monocyte chemoattractant protein-1, hepatocyte growth factor, resistin, leptin, and adiponectin were measured along with arylesterase, paraoxonase, and lactonase activities of PON1 in 107 postmenopausal women. Moreover, the direct effect of resistin on PON1 expression was evaluated in vitro. Multivariate analysis revealed that only resistin was significantly and inversely correlated with PON1-lactonase activities (r = −0.346, p < 0.001) regardless of confounding factors such as age or HDL-cholesterol. It is worth noting that no statistical link was found between adipokine and arylesterase or paraoxonase, the two promiscuous activities of PON1. Notably, resistin down-regulated PON1 expression occurred in hepatocellular carcinoma cultures. Our study suggests that resistin might be a negative modulator of PON1 expression and anti-oxidative activity.

Effect of a high sucrose and high fat diet in BDNF (+/-) mice on oxidative stress markers in adipose tissues

The purpose of this study was to investigate the effects of a high fat and a high sucrosediet in wild type and BDNF (+/-) mice on oxidative stress in epididymal and subcutaneousadipose tissues by measuring different markers of oxidative stress and antioxidant enzymes. Wild type (WT) and BDNF (+/-) male mice were divided into six groups receiving fed control diet (CD), high sucrose diet (HSD), or high fat diet (HFD) for four months. Levels of 3-nitrotyrosine (3-NT) increased in the HFD-fed BDNF (+/-) mice, while 4-hydroxynonenal (4-HNE) levels increased in the CD and HFD-fed BDNF (+/-) groups. Malondialdehyde (MDA) levels decreased in subcutaneous tissue compared to epididymal adipose tissue, independently of diet type. Superoxide dismutase (SOD) activity was reduced by HFD (p < 0.05), butglutathione peroxidase (GSH-Px) activity was increased by HSD in epididymal adipose tissuein BDNF (+/-) mice (p < 0.05). GSH-Px activities was increased by CD and HFD in subcutaneous adipose tissue of BDNF (+/-) (p < 0.05). SOD2 and GSH-Px3 expressions were only decreased by HSD in epididymal and subcutaneous adipose tissues of BDNF (+/-) mice (p < 0.05). In conclusion, reduced BDNF may increase OS in epididymal adipose tissue, but not in subcutaneous adipose tissue following HSD and HFD.

The role of the Hint1 protein in the metabolism of phosphorothioate oligonucleotides drugs and prodrugs, and the release of H2S under cellular conditions

Phosphorothioate oligonucleotides (PS-oligos) containing sulfur atom attached in a nonbridging position to the phosphorus atom at one or more internucleotide bond(s) are often used in medicinal applications. Their hydrolysis in cellular media proceeds mainly from the 3'-end, resulting in the appearance of nucleoside 5'-O-phosphorothioates ((d)NMPS), whose further metabolism is poorly understood. We hypothesize that the enzyme responsible for (d)NMPS catabolism could be Hint1, an enzyme that belongs to the histidine triad (HIT) superfamily and is present in all organisms. We previously found that (d)NMPS were desulfurated in vitro to yield (d)NMP and H₂S in a Hint1-assisted reaction. Here, we demonstrate that AMPS/GMPS/dGMPS introduced into HeLa/A549 cells are intracellularly converted into AMP/GMP/dGMP and H₂S. The level of the released H₂S was relative to the concentration of the compounds used and the reaction time. Using RNAi technology, we have shown decreased levels of AMPS/GMPS desulfuration in HeLa/A549 cells with reduced Hint1 levels. Finally, after transfection of a short Rp-d(A_PSA_PSA) oligomer into HeLa cells, the release of H₂S was observed. These results suggest that the metabolic pathway of PS-oligos includes hydrolysis into (d)NMPS (by cellular nucleases) followed by Hint1-promoted conversion of the resulting (d)NMPS into (d)NMP accompanied by H₂S elimination. Our observations may be also important for possible medicinal applications of (d)NMPS because H₂S is a gasotransmitter involved in many physiological and pathological processes.

Preventive Leptin Administration Protects Against Sepsis Through Improving Hypotension, Tachycardia, Oxidative Stress Burst, Multiple Organ Dysfunction, and Increasing Survival

Sepsis syndrome is the most important cause of mortality in critically ill patients admitted to intensive care units (ICUs). However, current therapies for its prevention and treatment are still unsatisfactory, and the mortality rate is still high. Non-septic ICU patients are vulnerable to acquire sepsis syndrome. Thus, a preventive treatment for this population is needed. During sepsis syndrome and endotoxemia, severe hypotension, tachycardia, oxidative and immune response increase, multiple organ dysfunction syndrome (MODS) and decreased survival are observed. Leptin administration protects against negative effects of sepsis syndrome and endotoxemia. Furthermore, it is has been reported that leptin elevates blood pressure mediated by sympathetic nervous system activation. However, whether leptin administration before sepsis induction mediates its protective effects during sepsis through blood pressure regulation is not known. Therefore, we investigated whether pre-treatment of leptin improves blood pressure and MODS, resulting in survival increase during endotoxemia. The results showed that leptin administration before endotoxemia induction reduced both the hypotension and tachycardia characteristically observed during endotoxemia. Notably, this protective effect was observed early and late in the course of endotoxemia. Endotoxemia-induced MODS decreased in leptin-treated rats, which was reflected in normal values for liver and kidney function, inhibition of muscle mass wasting and maintenance of glycemia. Furthermore, leptin pre-treatment decreased the oxidative stress burst in blood and blunted the increased pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 observed during endotoxemia. Remarkably, according to the leptin-induced increase in survival, leptin pre-administration decreased the risk for death associated with sepsis syndrome at early and late times after endotoxemia induction. These results show a potential preventive therapy against sepsis syndrome and endotoxemia in vulnerable patients, based in the beneficial actions of leptin.

Cancer and comorbidity: The role of leptin in breast cancer and associated pathologies

Obesity is an important risk factor for postmenopausal breast cancer and also a poor prognostic factor among cancer patients. Moreover, obesity is associated with a number of health disorders such as insulin resistance/type-2 diabetes mellitus, hypertension, and other cardiovascular diseases. Frequently, these health disorders exhibit as components/complications of the metabolic syndrome. Nevertheless, obesity-related diseases may coexist with postmenopausal breast cancer; and these comorbid conditions could be substantial. Therefore, it may be assumed that different diseases including breast cancer could originate from a common pathological background in excessive adipose tissue. Adipocyte-released hormone-like cytokine (or adipokine) leptin behaves differently in a normal healthy state and obesity. A growing body of evidence suggests an important role of leptin in our major obesity-related health issues such as insulin resistance, hypertension, and neoplasia. In this context, this review describes the relationships of the abovementioned pathologies with leptin.

Ultraviolet radiation, vitamin D and the development of obesity, metabolic syndrome and type-2 diabetes

Obesity is increasing in prevalence in many countries around the world. Its causes have been traditionally ascribed to a model where energy intake exceeds energy consumption. Reduced energy output in the form of exercise is associated with less sun exposure as many of these activities occur outdoors. This review explores the potential for ultraviolet radiation (UVR), derived from sun exposure, to affect the development of obesity and two of its metabolic co-morbidities, type-2 diabetes and metabolic syndrome. We here discuss the potential benefits (or otherwise) of exposure to UVR based on evidence from pre-clinical, human epidemiological and clinical studies and explore and compare the potential role of UVR-induced mediators, including vitamin D and nitric oxide. Overall, emerging findings suggest a protective role for UVR and sun exposure in reducing the development of obesity and cardiometabolic dysfunction, but more epidemiological and clinical research is required that focuses on measuring the direct associations and effects of exposure to UVR in humans.

Serum amyloid P component therapeutically attenuates atherosclerosis in mice via its effects on macrophages

Background: A hallmark of atherosclerosis is the formation of macrophage-derived foam cells. Serum amyloid P component (SAP), a member of the pentraxin family of proteins, is known to affect macrophage activation. However, the role of SAP in atherosclerosis is still unclear.

Methods: Apolipoprotein E-deficient (Apoe^-/-) mice fed a high-fat diet were given intraperitoneal injections of SAP (6 mg/kg) every other day for a total of 2 weeks to characterize atherosclerosis development.

Results: We showed that intraperitoneal injection of SAP attenuated atherosclerosis in Apoe^-/- mice. Immunostaining of aortic roots indicated that SAP was up-taken by the lesion area. In SAP-treated mice, serum paraoxonase1 (PON1) activity was increased whereas high-density lipoprotein inflammatory index (HII) was reduced. The cholesterol efflux rate in macrophages was elevated along with the expression of cholesterol efflux proteins. Through bioinformatics analysis followed by experimental validation, we found that proline/serine-rich coiled-coil protein 1 (Psrc1) was an important downstream effector of SAP in macrophages.

Conclusions: Our findings reveal an anti-atherosclerotic role of SAP and extend the current knowledge regarding this molecule as a marker for atherosclerosis.

Pravastatin improves risk factors but not ischaemic tolerance in obese rats

Statins are effective in management of dyslipidaemia, and a cornerstone of CVD prevention strategies. However, the impacts of their pleiotropic effects on other cardiovascular risk factors and myocardial responses to infarction are not well characterised. We hypothesised that pravastatin treatment in obesity improves lipid profiles, insulin-resistance and myocardial resistance to ischaemia/reperfusion (I/R) injury. Wistar rats were fed a control (C) chow or high carbohydrate and fat diet (HCFD) for 16 weeks with vehicle or pravastatin (prava 7.5 mg/kg/day) treatment for 8 weeks. At 16 weeks HOMAs were performed, blood samples collected and hearts excised for Langendorff perfusions/biochemical analyses. Anti-oxidant activity and proteins regulating mitochondrial fission/fusion and apoptosis were assessed. The HCFD increased body weight (736±15 vs. 655±12 g for C; P<0.001), serum triglycerides (2.91±0.52 vs. 1.64±0.26 mmol/L for C; P<0.001) and insulin-resistance (HOMA- 6.9±0.8 vs. 4.2±0.5 for C; P<0.05) while prava prevented diet induced changes and paradoxically increased lipid peroxidation. The HCFD increased infarct size (34.1±3.1% vs. 18.8±3.0% of AAR for C; P<0.05), which was unchanged by prava in C and HCFD animals. The HCFD decreased cardiac TxR activity and mitochondrial MFN-1 and increased mitochondrial DRP-1 (reducing MFN-1:DRP-1 ratio) and Bax expression, with the latter changes prevented by prava. While unaltered by diet, cytosolic levels of Bax and caspase-3 were reduced by prava in C and HCFD hearts (without changes in cleaved caspase-3). We conclude that obesity, hyper-triglyceridemia and impaired glycemic control in HCFD rats are countered by prava. Despite improved risk factors, prava did not reduce myocardial infarct size, potentially reflecting its complex pleiotropic impacts on cardiac GPX activity and MFN-1, DRP-1, caspase-3 and Bcl-2 proteins.

Hyperleptinemia positively associated with central arterial stiffness in hemodialysis patients

Objective

Leptin plays a role in stimulating vascular inflammation, vascular smooth muscle hypertrophy, and augmenting blood pressure, which contributes to the pathogenesis of atherosclerosis and leads to arterial stiffness. This vascular damage, measured by carotid-femoral pulse wave velocity (cfPWV), is recognized as an independent predictor of cardiovascular mortality in hemodialysis (HD) patients. The aim of this study was to evaluate the relationship between serum leptin and arterial stiffness in HD patients.

Patients and methods

In 112 of the 126 HD patients were eligible and their biochemical data were collected for analysis. Serum leptin level was measured using a commercial enzyme-linked immunosorbent assay kit. Carotid-femoral pulse wave velocity was measured by a validated tonometry system (SphygmoCor). Those have cfPWV values above 10 m/s are defined as the high arterial stiffness group.

Results

Among the participants, thirty-eight of them who were in the high arterial stiffness group, had a higher prevalence of diabetes mellitus (p = 0.002), age (p = 0.029), body mass index (BMI, p = 0.018), body fat mass (p = 0.001), hemoglobin (p = 0.040), and serum leptin levels (P<0.001). Multivariable logistic regression analysis showed that leptin (odds ratio [OR] 1.09; 95% confidence interval [CI] 1.04–1.14; p <0.001), diabetes (OR 7.17; CI 1.39–37.00; p = 0.019), body fat mass (OR 1.16; CI 1.02–1.33; p = 0.027); and hemoglobin (OR 2.11; CI 1.15–3.87; p = 0.015) were independently associated with arterial stiffness in HD patients.

Conclusion

In our study, hyperleptinemia was positively correlated to the high cfPWV and thus was related to high arterial stiffness in HD patients.

A Study on the Effects of the Use of Propofol in Experimental Model Inferior Epigastric Island Flap on Ischemia-Reperfusion Injury

Problems concerning vascular blood flow are the most frequently encountered ones after flap applications. The flap tissue starts to develop ischemia in patients with a vascular blood flow insufficiency. And reperfusion starts in those patients in whom the ischemia is temporary, triggering an ischemia-reperfusion injury depending on the duration of the ischemia. The aim of this study was to evaluate the effect of propofol, which is an anesthetic agent known to have an antioxidant effect and a free radical scavenging feature on the ischemia-reperfusion injury created on an experimental epigastric island flap.Thirty Sprague-Dawley rats were used in the study. The rats were divided into 3 groups of 10 rats each. Inferior epigastric artery-based abdominal flaps were prepared in all the groups. In group 1 (sham), the flap was elevated but no ischemia was applied. In groups 2 (control) and 3 (propofol), the flap was exposed to ischemia for 2 hours after it was elevated. All the rats were sacrificed and biochemical and histopathological assessments were made on the tissue samples taken on the 14th day. As a result of a comparison between the groups, the flap viability rates and the superoxide dismutase, total antioxidant capacity, and catalase values were found to be significantly higher (P < 0.001) in the propofol group while the malondialdehyde and total oxidative stress values were lower (P < 0.001). Based on the data obtained from the present study, the use of propofol was observed to have a protective effect against ischemia-reperfusion injuries in flap surgeries.

International Union of Basic and Clinical Pharmacology. CII: Pharmacological Modulation of H2S Levels: H2S Donors and H2S Biosynthesis Inhibitors

Over the last decade, hydrogen sulfide (H2S) has emerged as an important endogenous gasotransmitter in mammalian cells and tissues. Similar to the previously characterized gasotransmitters nitric oxide and carbon monoxide, H2S is produced by various enzymatic reactions and regulates a host of physiologic and pathophysiological processes in various cells and tissues. H2S levels are decreased in a number of conditions (e.g., diabetes mellitus, ischemia, and aging) and are increased in other states (e.g., inflammation, critical illness, and cancer). Over the last decades, multiple approaches have been identified for the therapeutic exploitation of H2S, either based on H2S donation or inhibition of H2S biosynthesis. H2S donation can be achieved through the inhalation of H2S gas and/or the parenteral or enteral administration of so-called fast-releasing H2S donors (salts of H2S such as NaHS and Na2S) or slow-releasing H2S donors (GYY4137 being the prototypical compound used in hundreds of studies in vitro and in vivo). Recent work also identifies various donors with regulated H2S release profiles, including oxidant-triggered donors, pH-dependent donors, esterase-activated donors, and organelle-targeted (e.g., mitochondrial) compounds. There are also approaches where existing, clinically approved drugs of various classes (e.g., nonsteroidal anti-inflammatories) are coupled with H2S-donating groups (the most advanced compound in clinical trials is ATB-346, an H2S-donating derivative of the non-steroidal anti-inflammatory compound naproxen). For pharmacological inhibition of H2S synthesis, there are now several small molecule compounds targeting each of the three H2S-producing enzymes cystathionine-β-synthase (CBS), cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase. Although many of these compounds have their limitations (potency, selectivity), these molecules, especially in combination with genetic approaches, can be instrumental for the delineation of the biologic processes involving endogenous H2S production. Moreover, some of these compounds (e.g., cell-permeable prodrugs of the CBS inhibitor aminooxyacetate, or benserazide, a potentially repurposable CBS inhibitor) may serve as starting points for future clinical translation. The present article overviews the currently known H2S donors and H2S biosynthesis inhibitors, delineates their mode of action, and offers examples for their biologic effects and potential therapeutic utility.

Obesity, bariatric surgery and oxidative stress

Introduction:

Obesity refers to the accumulation of fatty tissues and it favors the occurrence of oxidative stress. Alternatives that can contribute to body weight reduction have been investigated in order to reduce the production of reactive oxygen species responsible for tissue damage. The aim of the current study was to assess whether the oxidant and antioxidant markers of obese women before and after bariatric surgery were able to reduce oxidative damage.

Method:

We have assessed 16 morbidly obese women five days before and 180 days after the surgery. The control group comprised 16 non-obese women. Levels of thiobarbituric acid-reactive substances, carbonylated proteins, reduced glutathione and ascorbic acid were assessed in the patients' plasma.

Results:

Levels of lipid peroxidation and protein carbonylation in the pre-surgical obese women were higher than those of the controls and post-surgical obese women. Levels of reduced glutathione in the pre-surgical obese women were high compared to the controls, and declined after surgery. Levels of ascorbic acid fell in the pre--surgical obese women compared to the control and post-surgical obese women.

Conclusion:

Body weight influences the production of reactive oxygen species. Bariatric surgery, combined with weight loss and vitamin supplementation, reduces cellular oxidation, thus reducing tissue damage.

In Vivo Evaluation of the Toxic Effect of Ethyl Acetate Extracts of Marine Antibiotic Resistance Pseudomonas Species Derived from the Red Sea

Eighty-nine cultured Pseudomonas species isolated from the sediment and water samples collected from five industrial Red Sea regions that have been affected by petroleum and industry. Genotypic (exoT, exoS, exoU, exoY, lasA, lasB, rhlA, rhlB, Pf1, PAGI-1, -2, and -3) and phenotypic (DNase, elastase, lipase, protease, siderophore, antibiotic resistance patterns) characteristics were determined. Out of these isolates, nine Pseudomonas isolates were selected as the hyperactive virulence factors producers along with highly resistant pattern against all antibiotics of different classes included in this study. They were subjected to phenotypic and chemotypic characterization as well as molecular identification through 16S rRNA gene amplification and sequencing. The bioactive metabolites of these nine strains were extracted by ethyl acetate followed by evaluating their cytotoxic activity toward liver tissues, kidney tissues, and other biochemical activities in rat. Both EGY6 and EGY8 caused the highest significant reduction in the levels of packed cell volume (PCV), red blood cell count (RBC), and hemoglobin (Hb), which indicate that these Pseudomonas strain metabolites could cause anemia and toxic effects on hematological values in animals that were infected with them. Rats treated with the most toxic extract, EGY8, showed severe histopathological alterations in liver and kidney.

The Central Role of Biometals Maintains Oxidative Balance in the Context of Metabolic and Neurodegenerative Disorders

Traditionally, oxidative stress as a biological aspect is defined as an imbalance between the free radical generation and antioxidant capacity of living systems. The intracellular imbalance of ions, disturbance in membrane dynamics, hypoxic conditions, and dysregulation of gene expression are all molecular pathogenic mechanisms closely associated with oxidative stress and underpin systemic changes in the body. These also include aspects such as chronic immune system activation, the impairment of cellular structure renewal, and alterations in the character of the endocrine secretion of diverse tissues. All of these mentioned features are crucial for the correct function of the various tissue types in the body. In the present review, we summarize current knowledge about the common roots of metabolic and neurodegenerative disorders induced by oxidative stress. We discuss these common roots with regard to the way that (1) the respective metal ions are involved in the maintenance of oxidative balance and (2) the metabolic and signaling disturbances of the most important biometals, such as Mg²⁺, Zn²⁺, Se²⁺, Fe²⁺, or Cu²⁺, can be considered as the central connection point between the pathogenesis of both types of disorders and oxidative stress.

Insulin-Stimulated Bone Blood Flow and Bone Biomechanical Properties Are Compromised in Obese, Type 2 Diabetic OLETF Rats

Type 2 diabetes (T2D) increases skeletal fragility and fracture risk; however, the underlying mechanisms remain to be identified. Impaired bone vascular function, in particular insulin‐stimulated vasodilation and blood flow is a potential, yet unexplored mechanism. The purpose of this study was to determine the effects of T2D on femoral biomechanical properties, trabecular microarchitecture, and insulin‐stimulated bone vasodilation by comparison of hyperphagic Otsuka Long‐Evans Tokushima Fatty (OLETF) rats with normoglycemic control OLETF rats. Four‐week old, male OLETF rats were randomized to two groups: type 2 diabetes (O‐T2D) or normoglycemic control (O‐CON). O‐T2D were allowed ad libitum access to a rodent chow diet and O‐CON underwent moderate caloric restriction (30% restriction relative to intake of O‐T2D) to maintain normal body weight (BW) and glycemia until 40 weeks of age. Hyperphagic O‐T2D rats had significantly greater BW, body fat, and blood glucose than O‐CON. Total cross‐sectional area (Tt.Ar), cortical area (Ct.Ar), Ct.Ar/Tt.Ar, and polar moment of inertia of the mid‐diaphyseal femur adjusted for BW were greater in O‐T2D rats versus O‐CON. Whole‐bone biomechanical properties of the femur assessed by torsional loading to failure did not differ between O‐T2D and O‐CON, but tissue‐level strength and stiffness adjusted for BW were reduced in O‐T2D relative to O‐CON. Micro–computed tomography (μCT) of the distal epiphysis showed that O‐T2D rats had reduced percent bone volume, trabecular number, and connectivity density, and greater trabecular spacing compared with O‐CON. Basal tibial blood flow assessed by microsphere infusion was similar in O‐T2D and O‐CON, but the blood flow response to insulin stimulation in both the proximal epiphysis and diaphyseal marrow was lesser in O‐T2D compared to O‐CON. In summary, impaired insulin‐stimulated bone blood flow is associated with deleterious changes in bone trabecular microarchitecture and cortical biomechanical properties in T2D, suggesting that vascular dysfunction might play a causal role in diabetic bone fragility. © 2017 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

The role of selected adipokines and ghrelin in the prognosis after myocardial infarction in a 12-month follow-up in the presence of metabolic syndrome

INTRODUCTION

The aim of this study was to evaluate the predictive value of selected adipokines in the improvement in the ejection fraction and in the development of adverse cardiac remodeling during 12 months of follow-up among patients with an ST-segment elevation acute myocardial infarction (STEMI) in the presence of metabolic syndrome (MeS).

MATERIAL AND METHODS

The study population consisted of 69 patients (49 male; mean age: 59 ±10 years) with a first STEMI that was treated with a primary percutaneous coronary intervention (pPCI). In this group, 36 patients (18 male; mean age: 60 ±15 years) had MeS according to the definition of the International Diabetes Federation. The baseline clinical evaluation included a clinical examination and evaluation of the blood levels of C-reactive protein, ghrelin, resistin, and fasting glucose. Within 72 h after the STEMI, an echocardiographic examination was performed. A complete clinical evaluation was repeated after 12 months. Adverse cardiac remodeling was defined as an increase in the left ventricular end-diastolic volume of ≥ 8%. An improvement of the ejection fraction (EF) was defined as an increase of more than 5% in the EF.

RESULTS

A concentration of ghrelin ≤ 160.46 pg/ml (AUC = 0.71, p = 0.032) had a good predictive value for the occurrence of adverse left ventricular remodeling but only in the patients without MeS. Among the patients with MeS, a concentration of resistin ≤ 5196 pg/ml (AUC = 0.073, p = 0.024) had a good predictive value for the occurrence of left ventricular remodeling. A concentration of leptin > 52.18 pg/ml (AUC = 0.81, p < 0.0001) and resistin > 4419.27 ng/ml (AUC = 0.67, p = 0.049) had a good predictive value for improvement of the LVEF in the patients without MeS.

CONCLUSIONS

The selected adipokines had a good predictive value for the development of adverse cardiac remodeling and for improvement of the ejection fraction among patients after a STEMI in the presence of metabolic syndrome.

Influence of CYP2C9 and COX-2 Genetic Polymorphisms on Clinical Efficacy of Non-Steroidal Anti-Inflammatory Drugs in Treatment of Ankylosing Spondylitis

Background

The aim of this study was to evaluate the relationships of CYP2C9 and COX-2 genetic polymorphisms with therapeutic efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) in treatment of ankylosing spondylitis (AS).

Material/Methods

We enrolled 130 AS inpatients and outpatients in the Arthritis and Rheumatism Department of Peking University First Hospital and 106 healthy people getting routine check-ups between September 2013 and July 2014. CYP2C9 and COX-2 genetic polymorphisms were detected by PCR-RFLP. All AS patients underwent medical treatment and 12-week follow-up treatment. Score differences of BASDAI, ASAS20, ASAS50, and ASAS70 for AS patients with different genotypes before and after treatment were compared.

Results

In terms of COX-2-1290A/G and -1195G/A gene polymorphism genotype and allele frequency, the case group and control group were obviously different (all P<0.05), but CYP2C9*3 polymorphism genotype and allele frequency were not statistically different between the 2 groups (P>0.05). AS patients had improved BASDAI, ASAS20, ASAS50, and ASAS70 scores after they received NSAID treatment (all P<0.05). Furthermore, the efficacy of NSAID in treatment of AS and COX-2 gene −1290A/G and −1195G/A polymorphism were associated (all P<0.05), but it is not associated with CYP2C9 *3 polymorphism (all P>0.05).

Conclusions

COX-2-1290A/G and -1195G/A polymorphism may increase AS risk and they both can be considered as biological indicators for prediction of efficacy of NSAIDs in treatment of AS.

An observational study of haemostatic changes, leptin and soluble endoglin during pregnancy in women with different BMIs

Obesity increases the risk of venous thromboembolism (VTE) in pregnancy. The pathogenesis is hypothesized to be because of multiple factors including prothrombotic changes, but there has been minimal haemostatic research looking at the combined state of obesity and pregnancy. We aimed to determine whether variation in BMI in the third trimester of pregnancy was associated with prothrombotic changes. We recruited 110 women into four groups depending on their BMI at first antenatal appointment: normal, overweight, obese and morbidly obese. Women with increased risk of VTE, and/or receiving thromboprophylaxis, and/or more than 35 years and those in labour were excluded. Thromboelastography, platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen, prothrombin fragment 1 + 2, free and total protein S, plasminogen activator inhibitor type 1, tissue plasminogen activator antigen, D-dimers, soluble endoglin and leptin levels were measured. There were no significant differences in haemostatic measures with changing BMI. There was a positive correlation between BMI and both platelet count (correlation coefficient r = 0.214, P = 0.036) and leptin (r = 0.435, P < 0.001), but only leptin had a significant association with BMI once adjusted for age, gestation and parity. Despite recruitment into the morbidly obese group being suboptimal, these findings suggest that in pregnancy, the increased risk of VTE seen in obese mothers is not mediated through increased prothrombotic changes, and thus the increased risk of VTE in obese pregnant women may be because of other mechanisms, for example endothelial dysfunction, inflammation and venous stasis.

Role of Magnesium in Oxidative Stress in Individuals with Obesity

Adipose tissue is considered an endocrine organ that promotes excessive production of reactive oxygen species when in excess, thus contributing to lipid peroxidation. Magnesium deficiency contributes to the development of oxidative stress in obese individuals, as this mineral plays a role as an antioxidant, participates as a cofactor of several enzymes, maintains cell membrane stability and mitigates the effects of oxidative stress. The objective of this review is to bring together updated information on the participation of magnesium in the oxidative stress present in obesity. We conducted a search of articles published in the PubMed, SciELO and LILACS databases, using the keywords 'magnesium', 'oxidative stress', 'malondialdehyde', 'superoxide dismutase', 'glutathione peroxidase', 'reactive oxygen species', 'inflammation' and 'obesity'. The studies show that obese subjects have low serum concentrations of magnesium, as well as high concentrations of oxidative stress marker in these individuals. Furthermore, it is evident that the adequate intake of magnesium contributes to its appropriate homeostasis in the body. Thus, this review of current research can help define the need for intervention with supplementation of this mineral for the prevention and treatment of disorders associated with this chronic disease.

Elevated levels of adipokines predict outcome after acute myocardial infarction: A long-term follow-up of the Glucose Tolerance in Patients with Acute Myocardial Infarction cohort

OBJECTIVE

Adiponectin and leptin are associated with insulin resistance and cardiovascular disease. Information on the prognostic value after an acute myocardial infarction is still conflicting.

METHODS

Patients (n = 180) without known diabetes and with admission glucose of <11 mmol/L admitted for an acute myocardial infarction in 1998-2000 were followed for mortality and cardiovascular events (first of cardiovascular mortality/acute myocardial infarction/stroke/heart failure) until the end of 2011 (median: 11.6 years). Plasma adiponectin and leptin were related to outcome in Cox proportional-hazard regression analyses.

RESULTS

Median age was 64 years and 69% were male. Total mortality was 34% (n = 61) and 44% (n = 80) experienced a cardiovascular event. Adiponectin at discharge predicted cardiovascular events (hazard ratio; 95% confidence interval; 1.45; 1.02-2.07, p = 0.038), total mortality (2.53; 1.64-3.91, p < 0.001) and cancer mortality (3.64; 1.51-8.74, p = 0.004). After adjustment for age, sex, body mass index, previous myocardial infarction and heart failure, adiponectin predicted total mortality (1.79; 1.07-3.00, p = 0.027) but not cardiovascular events. High levels of leptin were associated with cardiovascular events during the first 7 years, after which the association was attenuated. Leptin did not predict total mortality.

CONCLUSION

In patients with acute myocardial infarction but without previously known diabetes, high levels of adiponectin at discharge predicted total mortality. The present results support the hypothesis that high rather than low levels of adiponectin predict mortality after acute myocardial infarction.

Alterations in serum paraoxonase-1 activity and lipid profile in chronic alcoholic patients infected with Strongyloides stercoralis

The objective of this study was to investigate paraoxonase-1 (PON1) activity, cortisol levels, and the lipid profile in the sera of alcoholic and non-alcoholic Strongyloides stercoralis-infected and uninfected individuals in a sample of 276 individuals attended at the National Health System in Salvador, Bahia, Brazil. The activity of PON1 was measured by the Beltowski method, serum lipids, and cortisol levels using commercial kits. PON1 activity was low in both alcoholic and non-alcoholic individuals infected with S. stercoralis. A positive correlation was observed between PON1 activity and cortisol concentration in alcoholic individuals who were not infected with S. stercoralis; whereas a negative correlation occurred in S. stercoralis-infected nonalcoholic individuals. The levels of triglycerides, LDL-C, and VLDL-C in S. stercoralis-infected alcoholic individuals were significantly lower than in uninfected alcoholic individuals. The high level of HDL-C and the low level of LDL-C, VLDL, triglycerides and PON1 activity in alcoholic patients infected with S. stercoralis evidenced an anti-atherogenic pattern.

Lessons from basic pancreatic beta cell research in type-2 diabetes and vascular complications

The changes in life-style with increased access of food and reduced physical activity have resulted in the global epidemic of obesity. Consequently, individuals with type 2 diabetes and cardiovascular disease have also escalated. A central organ in the development of diabetes is the pancreas, and more specifically the pancreatic beta cells within the islets of Langerhans. Beta cells have been assigned the important task of secreting insulin when blood glucose is increased to lower the glucose level. An early sign of diabetes pathogenesis is lack of first phase insulin response and reduced second phase secretion. In this review, which is based on the foreign investigator award lecture given at the JSDC meeting in Sendai in October 2016, we discuss a possible cellular explanation for the reduced first phase insulin response and how this can be influenced by lipids. Moreover, since patients with cardiovascular disease and high levels of cholesterol are often treated with statins, we summarize recent data regarding effects on statins on glucose homeostasis and insulin secretion. Finally, we suggest microRNAs (miRNAs) as central players in the adjustment of beta cell function during the development of diabetes. We specifically discuss miRNAs regarding their involvement in insulin secretion regulation, differential expression in type 2 diabetes, and potential as biomarkers for prediction of diabetes and cardiovascular complications.

Leptin-Induced Endothelium-Independent Vasoconstriction in Thoracic Aorta and Pulmonary Artery of Spontaneously Hypertensive Rats: Role of Calcium Channels and Stores

Decreased leptin-induced endothelium-dependent vasodilation has been reported in spontaneously hypertensive rats (SHR). Here, we report leptin-induced vasoconstriction in endothelium-denuded pulmonary artery and thoracic aorta from SHR and sought to characterize calcium handling underlying these mechanisms. Vasoreactivity to leptin was evaluated on pulmonary artery and thoracic aorta rings from 18 weeks old male SHR with or without calcium free medium, caffeine + thapsigargin + carbonyl cyanide-4-trifluoromethoxyphenylhydrazone emptying intracellular calcium stores, nifedipine a voltage-gated calcium channel inhibitor, SKF-96365 a transient receptor potential cation channels (TRPC) inhibitor, wortmaninn, a phosphatidylinositide 3-kinases (PI3K) inhibitor, or PD98059 a mitogen-activated protein kinase kinase (MAPKK) inhibitor. Calcium imaging was performed on cultured vascular smooth muscle cells incubated with leptin in presence or not of wortmaninn or PD98059. Leptin induced vasoconstriction in denuded pulmonary artery and thoracic aorta from SHR. Response was abolished when intra- or extracellular calcium stores were emptied, after blocking TRPC or voltage-dependent calcium channels or when using MAPKK or PI3K inhibitors. In vascular smooth muscle cells, leptin increased intracellular calcium. This rise was higher in SHR and abolished by MAPKK or PI3K inhibitors. TRPC6 gene expression was upregulated in arteries from SHR. Leptin-induced vasoconstriction in denuded arteries of SHR requires intracellular stores and is TRPC- and voltage-gated calcium channels dependent. Intracellular calcium increase is more pronounced in spontaneously hypertensive rats.