The NO/ONOO-cycle as the central cause of heart failure

Pulmonary Hypertension and Right Ventricle: A Pathophysiological Insight

Background

Pulmonary hypertension (PH) is a pulmonary vascular disease characterized by elevated pulmonary vascular pressure. Long-term PH, irrespective of its etiology, leads to increased right ventricular (RV) pressure, RV hypertrophy, and ultimately, RV failure.

Main body

Research indicates that RV failure secondary to hypertrophy remains the primary cause of mortality in pulmonary arterial hypertension (PAH). However, the impact of PH on RV structure and function under increased overload remains incompletely understood. Several mechanisms have been proposed, including extracellular remodeling, RV hypertrophy, metabolic disturbances, inflammation, apoptosis, autophagy, endothelial-to-mesenchymal transition, neurohormonal dysregulation, capillary rarefaction, and ischemia.

Conclusions

Studies have demonstrated the significant role of oxidative stress in the development of RV failure. Understanding the interplay among these mechanisms is crucial for the prevention and management of RV failure in patients with PH.

α-Tocotrienol Protects Neurons by Preventing Tau Hyperphosphorylation via Inhibiting Microtubule Affinity-Regulating Kinase Activation

In the pathological process of Alzheimer's disease, neuronal cell death is closely related to the accumulation of reactive oxygen species. Our previous studies have found that oxidative stress can activate microtubule affinity-regulating kinases, resulting in elevated phosphorylation levels of tau protein specifically at the Ser262 residue in N1E-115 cells that have been subjected to exposure to hydrogen peroxide. This process may be one of the pathogenic mechanisms of Alzheimer's disease. Vitamin E is a fat-soluble, naturally occurring antioxidant that plays a crucial role in biological systems. This study aimed to examine the probable processes that contribute to the inhibiting effect on the abnormal phosphorylation of tau protein and the neuroprotective activity of a particular type of vitamin E, α-tocotrienol. The experimental analysis revealed that α-tocotrienol showed significant neuroprotective effects in the N1E-115 cell line. Our data further suggest that one of the mechanisms underlying the neuroprotective effects of α-tocotrienol may be through the inhibition of microtubule affinity-regulated kinase activation, which significantly reduces the oxidative stress-induced aberrant elevation of p-Tau (Ser262) levels. These results indicate that α-tocotrienol may represent an intriguing strategy for treating or preventing Alzheimer's disease.

Central Causation of Autism/ASDs via Excessive [Ca2+]i Impacting Six Mechanisms Controlling Synaptogenesis during the Perinatal Period: The Role of Electromagnetic Fields and Chemicals and the NO/ONOO(-) Cycle, as Well as Specific Mutations

The roles of perinatal development, intracellular calcium [Ca2+]i, and synaptogenesis disruption are not novel in the autism/ASD literature. The focus on six mechanisms controlling synaptogenesis, each regulated by [Ca2+]i, and each aberrant in ASDs is novel. The model presented here predicts that autism epidemic causation involves central roles of both electromagnetic fields (EMFs) and chemicals. EMFs act via voltage-gated calcium channel (VGCC) activation and [Ca2+]i elevation. A total of 15 autism-implicated chemical classes each act to produce [Ca2+]i elevation, 12 acting via NMDA receptor activation, and three acting via other mechanisms. The chronic nature of ASDs is explained via NO/ONOO(-) vicious cycle elevation and MeCP2 epigenetic dysfunction. Genetic causation often also involves [Ca2+]i elevation or other impacts on synaptogenesis. The literature examining each of these steps is systematically examined and found to be consistent with predictions. Approaches that may be sed for ASD prevention or treatment are discussed in connection with this special issue: The current situation and prospects for children with ASDs. Such approaches include EMF, chemical avoidance, and using nutrients and other agents to raise the levels of Nrf2. An enriched environment, vitamin D, magnesium, and omega-3s in fish oil may also be helpful.

Oxidative Stress in Sepsis: A Focus on Cardiac Pathology

This study aims to analyze post-mortem human cardiac specimens, to verify and evaluate the existence or extent of oxidative stress in subjects whose cause of death has been traced to sepsis, through immunohistological oxidative/nitrosative stress markers. Indeed, in the present study, i-NOS, NOX2, and nitrotyrosine markers were higher expressed in the septic death group when compared to the control group, associated with also a significant increase in 8-OHdG, highlighting the pivotal role of oxidative stress in septic etiopathogenesis. In particular, 70% of cardiomyocyte nuclei from septic death specimens showed positivity for 8-OHdG. Furthermore, intense and massive NOX2-positive myocyte immunoreaction was noticed in the septic group, as nitrotyrosine immunostaining intense reaction was found in the cardiac cells. These results demonstrated a correlation between oxidative and nitrosative stress imbalance and the pathophysiology of cardiac dysfunction documented in cases of sepsis. Therefore, subsequent studies will focus on the expression of oxidative stress markers in other organs and tissues, as well as on the involvement of the intracellular pattern of apoptosis, to better clarify the complex pathogenesis of multi-organ failure, leading to support the rationale for including therapies targeting redox abnormalities in the management of septic patients.

Neuroinflammatory Response and Redox-regulation Activity of Hyperoside in Manganese-induced Neurotoxicity Model of Wistar Rats

BACKGROUND

Excessive manganese exposure can lead to neurotoxicity with detrimental effects on the brain. Neuroinflammatory responses and redox regulation play pivotal roles in this process. Exploring the impact of hyperoside in a Wistar rat model offers insights into potential neuroprotective strategies against manganese-induced neurotoxicity.

OBJECTIVE

The study investigated the neuroprotective efficacy of hyperoside isolated from the ethanol leaf extract of Gongronema latifolium (HELEGL), in the brain tissue of Wistar rats following 15 consecutive days of exposure to 30 mg/L of MnCl2.

METHODS

Control animals in Group 1 had access to regular drinking water, while animals in groups 2-4 were exposed to MnCl2 in their drinking water. Groups 3 and 4 also received additional HELEGL at doses of 100 mg/kg and 200 mg/kg of body weight, respectively. In Group 5, HELEGL at a dose of 100 mg/kg of body weight was administered alone. Treatment with HELEGL commenced on day 8 via oral administration.

RESULTS

HELEGL effectively mitigated MnCl2-induced memory impairment, organ-body weight discrepancies, and fluid intake deficits. Exposure to MnCl2 increased the activities or levels of various markers such as acyl peptide hydrolase, tumour necrosis factor-α, dipeptidyl peptidase IV, nitric oxide, IL-1β, prolyl oligopeptidase, caspase-3, myeloperoxidase, H2O2, and malondialdehyde, while it decreased the activities or levels of others, including AChE, BChE, DOPA, serotonin, epinephrine, norepinephrine, GST, GPx, CAT, SOD, GSH, and T-SH (p < 0.05). In contrast, HELEGL effectively counteracted the adverse effects of MnCl2 by alleviating oxidative stress, inflammation, apoptosis, mitochondrial dysfunction, cognitive deficits, and bolstering the antioxidant status. Moreover, HELEGL restored the normal histoarchitecture of the brain, which had been distorted by MnCl2.

CONCLUSION

In summary, HELEGL reversed the causative factors of neurodegenerative diseases induced by MnCl2 exposure, suggesting its potential for further exploration as a prospective therapeutic agent in the management of Alzheimer's disease and related forms of dementia.

Incidence, Risk Factors and Effective Treatment Strategies for Chylothorax After Pediatric Heart Surgeries: Retrospective Analysis of Large Database in Single Institution

Background

Risk factors for postoperative chylothorax in children who had cardiothoracic procedures are not always clear. Due to complex course in post-operative care, It's always challenging to find the risk factors, and their management.

Objective

The aim of our study was to identify the incidence, risk factors and effective treatment approaches for chylothorax after pediatric heart surgery.

Methods

Children who had the cardiac surgery and subsequently developed chylothorax were included in the study. The ratio of the experimental group to the control group was 1:2. Decannulations of extracorporeal membrane oxygenation (ECMO) were not included in the analysis of patient outcomes. For each patient, we keep track of their age, weight, gender, syndrome, RACH-1 scoring, fluid balance, bypass time, clamp time, redo operations, open or close heart surgeries, and rhythm difficulties. Care logs were kept for every single therapy that was administered. Primary outcome was chylothorax, with secondary outcomes included time in the intensive care unit (ICU), length of hospital stay (LOS), and death.

Results

5210 surgeries were performed in six years. 96 patients developed the chylothorax with incidence of 1.8%. In chylothorax group, mean weight was 6.7 ± 4.2, while mean age was 11.7 ± 15.2. Clamp time was 74.5 ± 53.5 versus 39.9 ± 13.7. Mean bypass time was 128.34(76.25) versus 84.3 ± 25.1 with an odds ratio 1.02 (Z test 0.0001). Six (6.3%) children with chylothorax had redo cardiac surgeries in the same admission (p-value 0.01) while none in other. Five (5.2%) cases got operated by thoracotomy, three from left side. Mean Chest tube duration was 10±7.8 days versus 3.8±2.4 in control group. (p-value 0.02). chylothorax resolved (mean resolving time = 4 days) in 76 (79.2%) children with monogen formula. Two patients receive midodrine with no significant effect. Four children underwent surgical repair for chylothorax.

Conclusion

Bypass time linearly increases incidence of chylothorax. Younger age, low weight, syndromic children, redo operations, non-open-heart surgeries, and arrhythmias also contribute to this. Gender, fluid balance, and RACHS-1 Scoring were not significant. While further research and testing are required for the use of midodrine. However, the low-fat formula of Monogen has proven to be an effective treatment.

iNOS contributes to heart failure with preserved ejection fraction through mitochondrial dysfunction and Akt S-nitrosylation

INTRODUCTION

Despite the high morbidity and mortality of heart failure with preserved fraction (HFpEF), there are currently no effective therapies for this condition. Moreover, the pathophysiological basis of HFpEF remains poorly understood.

OBJECTIVE

The aim of the present study was to investigate the role of inducible nitric oxide synthase (iNOS) and its underlying mechanism in a high-fat diet and N^ω-nitro-L-arginine methyl ester-induced HFpEF mouse model.

METHODS

The selective iNOS inhibitor L-NIL was used to examine the effects of short-term iNOS inhibition, whereas the long-term effects of iNOS deficiency were evaluated using iNOS-null mice. Cardiac and mitochondrial function, oxidative stress and Akt S-nitrosylation were then measured.

RESULTS

The results demonstrated that both pharmacological inhibition and iNOS knockout mitigated mitochondrial dysfunction, oxidative stress and Akt S-nitrosylation, leading to an ameliorated HFpEF phenotype in mice. In vitro, iNOS directly induced Akt S-nitrosylation at cysteine 224 residues , leading to oxidative stress, while inhibiting insulin-mediated glucose uptake in myocytes.

CONCLUSION

Altogether, the present findings suggested an important role for iNOS in the pathophysiological development of HFpEF, indicating that iNOS inhibition may represent a potential therapeutic strategy for HFpEF.

Caregiver's perspectives on the Central Nervous System infection illness trajectory among older persons with dementia in Northern Uganda-a qualitative community-based study

BACKGROUND

Few studies have explored the Central Nervous System (CNS) infection illness trajectory among older persons with dementia in sub-Saharan African (SSA) settings. This study explored the Caregiver's perspectives on the Central Nervous System infection illness trajectory among the older persons with dementia in Northern Uganda.

METHODS

This was a qualitative study conducted in Lira District northern Uganda in March 2022 amongst purposively selected 20 caregivers of the older persons aged 50 + years with a positive history of CNS infection and later life dementia. Data were collected using an in-depth interview guide. Audio recordings and field notes of the interviews were undertaken. The interviews generated data on the CNS infection illness trajectory from onset to the current demented state of the older persons. The audio-recorded interviews were transcribed verbatim before manual reflective thematic analysis.

RESULTS

Older persons with a positive history of CNS infection illness and later life dementia in rural northern Uganda presented with symptoms of early life CNS infection illness ranging from neck pain, back pain, chronic headache, and fatigue. There were also manifestations of comorbidities particularly road traffic accidents involving traumatic injury to the head, neck, and spine, high blood pressure, chronic headache, and or their medications in the older person's trajectory to later life dementia. A plurality of healthcare which included both formal and informal healthcare medicines was sought and utilized for the treatment and care of the CNS infection illness and dementia by the older persons amidst improper diagnosis and mismanagement.

CONCLUSIONS AND RECOMMENDATIONS

Older persons with early-life CNS infections illness and later-life dementia were reported to present with symptoms including neck pain, back pain, chronic headache, high blood pressure, and fatigue. The reported symptoms of CNS infection illness may be intertwined with co-morbidities particularly traumatic injury involving the head, neck, and spine, high blood pressure, and chronic headache. Healthcare professionals should integrate routine screening of older persons for the history of CNS infections, chronic headache, high blood pressure, trauma to the head, neck, and spine, and dementia and early treatment.

Low Intensity Electromagnetic Fields Act via Voltage-Gated Calcium Channel (VGCC) Activation to Cause Very Early Onset Alzheimer's Disease: 18 Distinct Types of Evidence

Electronically generated electromagnetic fields (EMFs) including those used in wireless communication such as cell phones, Wi-Fi and smart meters, are coherent, producing very high electric and magnetic forces which act on the voltage sensor of voltage-gated calcium channels to produce increases in intracellular calcium [Ca2+]i. The calcium hypothesis of Alzheimer's disease (AD) has shown that each of the important AD-specific and nonspecific causal elements are produced by excessive [Ca2+]i. [Ca2+]i acts in AD via excessive calcium signaling and the peroxynitrite/oxidative stress/inflammation pathway which are each elevated by EMFs. An apparent vicious cycle in AD involves amyloid-beta protein (A) and [Ca2+]i. Three types of epidemiology each suggest EMF causation of AD including early onset AD. Extensive animal model studies show that low intensity EMFs cause neurodegeneration including AD, with AD animals having elevated levels of A, amyloid precursor protein and BACE1. Rats exposed to pulsed EMFs every day are reported to develop universal or near universal very very very early onset neurodegeneration including AD; these findings are superficially similar to humans with digital dementia. EMFs producing modest increases in [Ca2+]i can also produce protective, therapeutic effects. The therapeutic pathway and peroxynitrite pathway inhibit each other. A summary of 18 different findings is provided, which collectively provide powerful evidence for EMF causation of AD. The author is concerned that smarter, more highly pulsed "smart" wireless communication may cause widespread very, very early onset AD in human populations.

miRNAs may play a major role in the control of gene expression in key pathobiological processes in Chagas disease cardiomyopathy

Chronic Chagas disease cardiomyopathy (CCC), an especially aggressive inflammatory dilated cardiomyopathy caused by lifelong infection with the protozoan Trypanosoma cruzi, is a major cause of cardiomyopathy in Latin America. Although chronic myocarditis may play a major pathogenetic role, little is known about the molecular mechanisms responsible for its severity. The aim of this study is to study the genes and microRNAs expression in tissues and their connections in regards to the pathobiological processes. To do so, we integrated for the first time global microRNA and mRNA expression profiling from myocardial tissue of CCC patients employing pathways and network analyses. We observed an enrichment in biological processes and pathways associated with the immune response and metabolism. IFNγ, TNF and NFkB were the top upstream regulators. The intersections between differentially expressed microRNAs and differentially expressed target mRNAs showed an enrichment in biological processes such as Inflammation, inflammation, Th1/IFN-γ-inducible genes, fibrosis, hypertrophy, and mitochondrial/oxidative stress/antioxidant response. MicroRNAs also played a role in the regulation of gene expression involved in the key cardiomyopathy-related processes fibrosis, hypertrophy, myocarditis and arrhythmia. Significantly, a discrete number of differentially expressed microRNAs targeted a high number of differentially expressed mRNAs (>20) in multiple processes. Our results suggest that miRNAs orchestrate expression of multiple genes in the major pathophysiological processes in CCC heart tissue. This may have a bearing on pathogenesis, biomarkers and therapy.

Chronic Chagas disease cardiomyopathy (CCC), an aggressive dilated cardiomyopathy caused by Trypanosoma cruzi, is a major cause of cardiomyopathy in Latin America. Little is known about the molecular mechanisms responsible for its severity. Authors study the possible role of microRNAs in the regulation of gene expression in relevant pathways and pathobiological processes. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) -small RNAs that can regulate gene expression—associated to severe cardiomyopathy development. The inflammatory mediator Interferon-γ was the most likely inducer of gene expression in CCC, and most genes belonged to the immune response, fibrosis, hypertrophy and mitochondrial metabolism. A discrete number of differentially expressed mRNAs targeted a high number of differentially expressed mRNAs in multiple processes. Moreover, several pathways had multiple targets regulated by microRNAs, suggesting synergic effect. Results suggest that microRNAs orchestrate expression of multiple genes in the major pathophysiological processes in CCC heart tissue.

Myeloid-Derived Suppressor Cells in Colorectal Cancer

Colorectal cancer (CRC) remains one of the most common malignancies diagnosed worldwide. The pathogenesis of CRC is complex and involves, among others, accumulation of genetic predispositions and epigenetic factors, dietary habits, alterations in gut microbiota, and lack of physical activity. A growing body of evidence suggests that immune cells play different roles in CRC, comprising both pro- and anti-tumorigenic functions. Immunosuppression observed during cancer development and progression is a result of the orchestration of many cell types, including myeloid-derived suppressor cells (MDSCs). MDSCs, along with other cells, stimulate tumor growth, angiogenesis, and formation of metastases. This article focuses on MDSCs in relation to their role in the initiation and progression of CRC. Possible forms of immunotherapies targeting MDSCs in CRC are also discussed.

Bradykinin Type 1 Receptor - Inducible Nitric Oxide Synthase: A New Axis Implicated in Diabetic Retinopathy

Compelling evidence suggests a role for the inducible nitric oxide synthase, iNOS, and the bradykinin type 1 receptor (B1R) in diabetic retinopathy, including a possible control of the expression and activity of iNOS by B1R. In diabetic retina, both iNOS and B1R contribute to inflammation, oxidative stress, and vascular dysfunction. The present study investigated whether inhibition of iNOS has any impact on inflammatory/oxidative stress markers and on the B1R-iNOS expression, distribution, and action in a model of type I diabetes. Diabetes was induced in 6-week-old Wistar rats by streptozotocin (65 mg.kg^-1, i.p.). The selective iNOS inhibitor 1400W (150 μg.10 μl^-1) was administered twice a day by eye-drops during the second week of diabetes. The retinae were collected 2 weeks after diabetes induction to assess the protein and gene expression of markers by Western blot and qRT-PCR, the distribution of iNOS and B1R by fluorescence immunocytochemistry, and the vascular permeability by the Evans Blue dye technique. Diabetic retinae showed enhanced expression of iNOS, B1R, carboxypeptidase M (involved in the biosynthesis of B1R agonists), IL-1β, TNF-α, vascular endothelium growth factor A (VEGF-A) and its receptor, VEGF-R2, nitrosylated proteins and increased vascular permeability. All those changes were reversed by treatment with 1400W. Moreover, the additional increase in vascular permeability in diabetic retina induced by intravitreal injection of R-838, a B1R agonist, was also prevented by 1400W. Immunofluorescence staining highlighted strong colocalization of iNOS and B1R in several layers of the diabetic retina, which was prevented by 1400W. This study suggests a critical role for iNOS and B1R in the early stage of diabetic retinopathy. B1R and iNOS appear to partake in a mutual auto-induction and amplification loop to enhance nitrogen species formation and inflammation in diabetic retina. Hence, B1R-iNOS axis deserves closer scrutiny in targeting diabetic retinopathy.

Disease Tolerance and Pathogen Resistance Genes May Underlie Trypanosoma cruzi Persistence and Differential Progression to Chagas Disease Cardiomyopathy

Chagas disease is caused by infection with the protozoan Trypanosoma cruzi and affects over 8 million people worldwide. In spite of a powerful innate and adaptive immune response in acute infection, the parasite evades eradication, leading to a chronic persistent infection with low parasitism. Chronically infected subjects display differential patterns of disease progression. While 30% develop chronic Chagas disease cardiomyopathy (CCC)—a severe inflammatory dilated cardiomyopathy—decades after infection, 60% of the patients remain disease-free, in the asymptomatic/indeterminate (ASY) form, and 10% develop gastrointestinal disease. Infection of genetically deficient mice provided a map of genes relevant for resistance to T. cruzi infection, leading to the identification of multiple genes linked to survival to infection. These include pathogen resistance genes (PRG) needed for intracellular parasite destruction, and genes involved in disease tolerance (protection against tissue damage and acute phase death—DTG). All identified DTGs were found to directly or indirectly inhibit IFN-γ production or Th1 differentiation. We hypothesize that the absolute need for DTG to control potentially lethal IFN-γ PRG activity leads to T. cruzi persistence and establishment of chronic infection. IFN-γ production is higher in CCC than ASY patients, and is the most highly expressed cytokine in CCC hearts. Key DTGs that downmodulate IFN-γ, like IL-10, and Ebi3/IL27p28, are higher in ASY patients. Polymorphisms in PRG and DTG are associated with differential disease progression. We thus hypothesize that ASY patients are disease tolerant, while an imbalance of DTG and IFN-γ PRG activity leads to the inflammatory heart damage of CCC.

How chronic administration of benzodiazepines leads to unexplained chronic illnesses: A hypothesis

It is thought that an ill defined biochemical cascade may lead to protracted withdrawal symptoms subsequent to discontinuance of routine use of benzodiazepine class drugs and establish chronic illness in some patients. In this review, published findings are presented that support the novel concept that withdrawal from benzodiazepine class drugs can trigger elevated and sustained levels of a potent oxidant called peroxynitrite via potentiation of the L-type voltage-gated calcium channels, and in the later stages of withdrawal, via excessive N-methyl-D-aspartate receptor activity, as well. Potentiation of L-type voltage-gated calcium channels and excessive N-methyl-D-aspartate receptor activity both result in calcium influx into the cell that triggers nitric oxide synthesis. In pathophysiological conditions, such increased nitric oxide synthesis leads to peroxynitrite formation. The downstream effects of peroxynitrite formation that may occur during withdrawal ultimately lead to further peroxynitrite production in a system of overlapping vicious cycles collectively referred to as the NO/ONOO(-) cycle. Once triggered, the elements of the NO/ONOO(-) cycle perpetuate pathophysiology, perhaps including reduced GABA_A receptor functioning, that may explain protracted withdrawal associated symptoms while the vicious cycle nature of the NO/ONOO(-) cycle may explain how withdrawal becomes a chronic state. Suboptimal levels of tetrahydrobiopterin may be one risk factor for the development of the protracted withdrawal syndrome as this will lead to partial nitric oxide uncoupling and resultant peroxynitrite formation. Nitric oxide uncoupling results in superoxide production as calcium-dependent nitric oxide synthases attempt to produce nitric oxide in response to L-type voltage-gated calcium channel-mediated calcium influx that is known to occur during withdrawal. The combination of nitric oxide and superoxide produced, as when partial uncoupling occurs, react together in a very rapid, diffusion limited reaction to form peroxynitrite and thereby trigger the NO/ONOO(-) cycle. The NO/ONOO(-) cycle may explain the nature of the protracted withdrawal syndrome and the related constellation of symptoms that are also common in other illnesses characterized as NO/ONOO(-) disorders such as myalgic encephalomyelitis/chronic fatigue syndrome and fibromyalgia.

Role of cardiac inflammation in right ventricular failure

Right ventricular failure (RVF) is the main determinant of mortality in patients with pulmonary arterial hypertension (PAH). Although the exact pathophysiology underlying RVF remains unclear, inflammation may play an important role, as it does in left heart failure. Perivascular pulmonary artery and systemic inflammation is relatively well studied and known to contribute to the initiation and maintenance of the pulmonary vascular insult in PAH. However, less attention has been paid to the role of cardiac inflammation in RVF and PAH. Consistent with many other types of heart failure, cardiac inflammation, triggered by systemic and local stressors, has been shown in RVF patients as well as in RVF animal models. RV inflammation likely contributes to impaired RV contractility, maladaptive remodelling and a vicious circle between RV and pulmonary vascular injury. Although the potential to improve RV function through anti-inflammatory therapy has not been tested, this approach has been applied clinically in left ventricular failure patients, with variable success. Because inflammation plays a dual role in the development of both pulmonary vascular pathology and RVF, anti-inflammatory therapies may have a potential double benefit in patients with PAH and associated RVF.

A Molecular Neurobiological Approach to Understanding the Aetiology of Chronic Fatigue Syndrome (Myalgic Encephalomyelitis or Systemic Exertion Intolerance Disease) with Treatment Implications

Currently, a psychologically based model is widely held to be the basis for the aetiology and treatment of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME)/systemic exertion intolerance disease (SEID). However, an alternative, molecular neurobiological approach is possible and in this paper evidence demonstrating a biological aetiology for CFS/ME/SEID is adduced from a study of the history of the disease and a consideration of the role of the following in this disease: nitric oxide and peroxynitrite, oxidative and nitrosative stress, the blood–brain barrier and intestinal permeability, cytokines and infections, metabolism, structural and chemical brain changes, neurophysiological changes and calcium ion mobilisation. Evidence is also detailed for biologically based potential therapeutic options, including: nutritional supplementation, for example in order to downregulate the nitric oxide-peroxynitrite cycle to prevent its perpetuation; antiviral therapy; and monoclonal antibody treatment. It is concluded that there is strong evidence of a molecular neurobiological aetiology, and so it is suggested that biologically based therapeutic interventions should constitute a focus for future research into CFS/ME/SEID.

Integration of miRNA and gene expression profiles suggest a role for miRNAs in the pathobiological processes of acute Trypanosoma cruzi infection

Chagas disease, caused by the parasite Trypanosoma cruzi, is endemic in Latin America. Its acute phase is associated with high parasitism, myocarditis and profound myocardial gene expression changes. A chronic phase ensues where 30% develop severe heart lesions. Mouse models of T. cruzi infection have been used to study heart damage in Chagas disease. The aim of this study was to provide an interactome between miRNAs and their targetome in Chagas heart disease by integrating gene and microRNA expression profiling data from hearts of T. cruzi infected mice. Gene expression profiling revealed enrichment in biological processes and pathways associated with immune response and metabolism. Pathways, functional and upstream regulator analysis of the intersections between predicted targets of differentially expressed microRNAs and differentially expressed mRNAs revealed enrichment in biological processes and pathways such as IFNγ, TNFα, NF-kB signaling signatures, CTL-mediated apoptosis, mitochondrial dysfunction, and Nrf2-modulated antioxidative responses. We also observed enrichment in other key heart disease-related processes like myocarditis, fibrosis, hypertrophy and arrhythmia. Our correlation study suggests that miRNAs may be implicated in the pathophysiological processes taking place the hearts of acutely T. cruzi-infected mice.

Low Nasal NO in Congenital Heart Disease With Systemic Right Ventricle and Postcardiac Transplantation

Background

NO bioavailability has not been systematically examined in congenital heart disease (CHD). To assess NO in patients with CHD, we measured nasal NO (nNO) generated by the nasal epithelia, given blood NO is difficult to measure (half‐life, <2 ms). Given NO's role in hemodynamic regulation and the association of NO bioavailability with heart failure risk, we hypothesized NO levels may differ with varying severity of CHD physiologic characteristics.

Methods and Results

Six‐hundred eighteen subjects, 483 with CHD and 135 controls, had nNO measured noninvasively via the nares using American Thoracic Society/European Respiratory Society guidelines. Subjects were dichotomized as having low or normal nNO based on age‐specific cutoff values. Prevalence of low nNO was examined by various CHD physiologic feature types. Low nNO was more prevalent with CHD than controls (odds ratio, 2.28; P=0.001). A logistic regression model showed overall significance (P=0.035) for single ventricle, systemic right ventricle, ventricular dysfunction, oxygen desaturation, and heterotaxy predicting low nNO, with systemic right ventricle independently having twice the odds of low nNO (odds ratio, 2.04; P=0.014). Patients with low nNO had a higher risk of experiencing heart transplant or death (hazard ratio, 2.75; P=0.048), and heart transplant recipients (N=16) exhibited 5 times the odds of low nNO (69% versus 30%; odds ratio, 5.1; P=0.001).

Conclusions

Patients with CHD have increased prevalence of low nNO, with highest odds seen with systemic right ventricle and heart transplant. Further studies are needed to investigate heart failure risks in patients with CHD with left versus right systemic ventricle physiologic characteristics and utility of low nNO for predicting heart failure risk.

The Pathophysiology of Nitrogen Dioxide During Inhaled Nitric Oxide Therapy

Administration of inhaled nitric oxide (NO) with the existing compressed gas delivery systems is associated with unavoidable codelivery of nitrogen dioxide (NO2), an unwanted toxic contaminant that forms when mixed with oxygen. The NO2 is generated when NO is diluted with O2-enriched air before delivery to the patient. When NO2 is inhaled by the patient, it oxidizes protective antioxidants within the epithelial lining fluid (ELF) and triggers extracellular damage in the airways. The reaction of NO2 within the ELF triggers oxidative stress (OS), possibly leading to edema, bronchoconstriction, and a reduced forced expiratory volume in 1 second. Nitrogen dioxide has been shown to have deleterious effects on the airways of high-risk patients including neonates, patients with respiratory and heart failure, and the elderly. Minimizing co-delivery of NO2 for the next generation delivery systems will be a necessity to fully optimize the pulmonary perfusion of NO because of vasodilation, whereas minimizing the negative ventilatory and histopathological effects of NO2 exposure during inhaled NO therapy.

A large scale Plasmodium vivax- Saimiri boliviensis trophozoite-schizont transition proteome

Plasmodium vivax is a complex protozoan parasite with over 6,500 genes and stage-specific differential expression. Much of the unique biology of this pathogen remains unknown, including how it modifies and restructures the host reticulocyte. Using a recently published P. vivax reference genome, we report the proteome from two biological replicates of infected Saimiri boliviensis host reticulocytes undergoing transition from the late trophozoite to early schizont stages. Using five database search engines, we identified a total of 2000 P. vivax and 3487 S. boliviensis proteins, making this the most comprehensive P. vivax proteome to date. PlasmoDB GO-term enrichment analysis of proteins identified at least twice by a search engine highlighted core metabolic processes and molecular functions such as glycolysis, translation and protein folding, cell components such as ribosomes, proteasomes and the Golgi apparatus, and a number of vesicle and trafficking related clusters. Database for Annotation, Visualization and Integrated Discovery (DAVID) v6.8 enriched functional annotation clusters of S. boliviensis proteins highlighted vesicle and trafficking-related clusters, elements of the cytoskeleton, oxidative processes and response to oxidative stress, macromolecular complexes such as the proteasome and ribosome, metabolism, translation, and cell death. Host and parasite proteins potentially involved in cell adhesion were also identified. Over 25% of the P. vivax proteins have no functional annotation; this group includes 45 VIR members of the large PIR family. A number of host and pathogen proteins contained highly oxidized or nitrated residues, extending prior trophozoite-enriched stage observations from S. boliviensis infections, and supporting the possibility of oxidative stress in relation to the disease. This proteome significantly expands the size and complexity of the known P. vivax and Saimiri host iRBC proteomes, and provides in-depth data that will be valuable for ongoing research on this parasite’s biology and pathogenesis.

Modulation of N-methyl-d-aspartate receptors in isolated rat heart

Considering the limited data on the role of NMDA-Rs in the cardiovascular system, the aim of the present study was to examine the effects of NMDA and DL-Hcy TLHC, alone and in combination with glycine, memantine, and ifenprodil, in the isolated rat heart. The hearts of Wistar albino rats were retrogradely perfused according to the Langendorff technique at a constant perfusion pressure. The experimental protocol for all experimental groups included the stabilization period, application of estimated substance for 5 min, followed by a washout period of 10 min. Using a sensor placed in the left ventricle, we registered the following parameters of myocardial function: dp/dt_max, dp/dt_min, SLVP, DVLP, HR; CF was measured using flowmetry). We estimated the following oxidative stress biomarkers in the coronary venous effluent using spectrophotometry: TBARS, NO₂^-, O₂^-, and H₂O₂. NMDA alone did not induce any change in any of the observed parameters, while DL-Hcy TLHC alone, as well as a combined application of NMDA and DL-Hcy TLHC with glycine, induced a reduction of most cardiodynamic parameters. Memantine and ifenprodil induced a reduction of cardiodynamic parameters and CF, as well as some oxidative stress biomarkers.

Can Adiponectin Help us to Target Diastolic Dysfunction?

Adiponectin is the most abundant adipokine and exhibits anti-inflammatory, antiatherogenic and antidiabetic properties. Unlike other adipokines, it inversely correlates with body weight and obesity-linked cardiovascular complications. Diastolic dysfunction is the main mechanism responsible for approximately half of all heart failure cases, the so-called heart failure with preserved ejection fraction (HFpEF), but therapeutic strategies specifically directed towards these patients are still lacking. In the last years, a link between adiponectin and diastolic dysfunction has been suggested. There are several mechanisms through which adiponectin may prevent most of the pathophysiologic mechanisms underlying diastolic dysfunction and HFpEF, including the prevention of myocardial hypertrophy, cardiac fibrosis, nitrative and oxidative stress, atherosclerosis and inflammation, while promoting angiogenesis. Thus, understanding the mechanisms underlying adiponectin-mediated improvement of diastolic function has become an exciting field of research, making adiponectin a promising therapeutic target. In this review, we explore the relevance of adiponectin signaling for the prevention of diastolic dysfunction and identify prospective therapeutic targets aiming at the treatment of this clinical condition.

Targeting TRAF3IP2 by Genetic and Interventional Approaches Inhibits Ischemia/Reperfusion-induced Myocardial Injury and Adverse Remodeling

Re-establishing blood supply is the primary goal for reducing myocardial injury in subjects with ischemic heart disease. Paradoxically, reperfusion results in nitroxidative stress and a marked inflammatory response in the heart. TRAF3IP2 (TRAF3 Interacting Protein 2; previously known as CIKS or Act1) is an oxidative stress-responsive cytoplasmic adapter molecule that is an upstream regulator of both IκB kinase (IKK) and c-Jun N-terminal kinase (JNK), and an important mediator of autoimmune and inflammatory responses. Here we investigated the role of TRAF3IP2 in ischemia/reperfusion (I/R)-induced nitroxidative stress, inflammation, myocardial dysfunction, injury, and adverse remodeling. Our data show that I/R up-regulates TRAF3IP2 expression in the heart, and its gene deletion, in a conditional cardiomyocyte-specific manner, significantly attenuates I/R-induced nitroxidative stress, IKK/NF-κB and JNK/AP-1 activation, inflammatory cytokine, chemokine, and adhesion molecule expression, immune cell infiltration, myocardial injury, and contractile dysfunction. Furthermore, Traf3ip2 gene deletion blunts adverse remodeling 12 weeks post-I/R, as evidenced by reduced hypertrophy, fibrosis, and contractile dysfunction. Supporting the genetic approach, an interventional approach using ultrasound-targeted microbubble destruction-mediated delivery of phosphorothioated TRAF3IP2 antisense oligonucleotides into the LV in a clinically relevant time frame significantly inhibits TRAF3IP2 expression and myocardial injury in wild type mice post-I/R. Furthermore, ameliorating myocardial damage by targeting TRAF3IP2 appears to be more effective to inhibiting its downstream signaling intermediates NF-κB and JNK. Therefore, TRAF3IP2 could be a potential therapeutic target in ischemic heart disease.

Ischemic postconditioning protects the heart against ischemia-reperfusion injury via neuronal nitric oxide synthase in the sarcoplasmic reticulum and mitochondria

As a result of its spatial confinement in cardiomyocytes, neuronal nitric oxide synthase (nNOS) is thought to regulate mitochondrial and sarcoplasmic reticulum (SR) function by maintaining nitroso-redox balance and Ca²⁺ cycling. Thus, we hypothesize that ischemic postconditioning (IPostC) protects hearts against ischemic/reperfusion (I/R) injury through an nNOS-mediated pathway. Isolated mouse hearts were subjected to I/R injury in a Langendorff apparatus, H9C2 cells and primary neonatal rat cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) in vitro. IPostC, compared with I/R, decreased infarct size and improved cardiac function, and the selective nNOS inhibitors abolished these effects. IPostC recovered nNOS activity and arginase expression. IPostC also increased AMP kinase (AMPK) phosphorylation and alleviated oxidative stress, and nNOS and AMPK inhibition abolished these effects. IPostC increased nitrotyrosine production in the cytosol but decreased it in mitochondria. Enhanced phospholamban (PLB) phosphorylation, normalized SR function and decreased Ca²⁺ overload were observed following the recovery of nNOS activity, and nNOS inhibition abolished these effects. Similar effects of IPostC were demonstrated in cardiomyocytes in vitro. IPostC decreased oxidative stress partially by regulating uncoupled nNOS and the nNOS/AMPK/peroxisome proliferator-activated receptor gamma coactivator 1 alpha/superoxide dismutase axis, and improved SR function through increasing SR Ca²⁺ load. These results suggest that IPostC protected hearts against I/R injury via an nNOS-mediated pathway.

Antioxidant and Anti-Inflammatory Effects of Rhei Rhizoma and Coptidis Rhizoma Mixture on Reflux Esophagitis in Rats

The purpose of this study was to investigate the antioxidant and anti-inflammatory effects of the combined extract of Rhei rhizoma and Coptidis rhizoma (RC-mix) in experimental model of acute reflux esophagitis. The antioxidant activity was assessed by in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. RC-mix was given at 100, 200, and 400 mg/kg body weight 2 h prior to induction of reflux esophagitis (RE). After 5 h, the effects of RC-mix treated rats were compared with those of normal and control rats. The representative flavonoid contents of RC-mix, such as sennoside A, epiberberine, coptisine, palmatine, and berberine, were detected using HPLC. The elevated esophageal mucosa damage was markedly ameliorated by RC-mix treatment in a dose-dependent manner. Furthermore, the administration of RC-mix reduced the increase of serum reactive oxygen species (ROS) and peroxynitrite (ONOO(-)). The improvement of superoxide dismutase (SOD) and heme oxygenase-1 (HO-1) levels were marked in the group given RC-mix. Moreover, the elevation of inflammatory mediators and cytokines by nuclear factor-kappa B (NF-κB) activation in control rats decreased by RC-mix pretreatment. These results indicate that RC-mix treatment reduces the pathological states of esophagitis via regulating NF-κB mediated inflammation related to oxidative stress.

Enhanced nitric oxide generation from nitric oxide synthases as the cause of increased peroxynitrite formation during acute restraint stress: Effects on carotid responsiveness to angiotensinergic stimuli in type-1 diabetic rats

Diabetes mellitus is associated with reactive oxygen and nitrogen species accumulation. Behavioral stress increases nitric oxide production, which may trigger a massive impact on vascular cells and accelerate cardiovascular complications under oxidative stress conditions such as Diabetes. For this study, type-1 Diabetes mellitus was induced in Wistar rats by intraperitoneal injection of streptozotocin. After 28 days, cumulative concentration-response curves for angiotensin II were obtained in endothelium-intact carotid rings from diabetic rats that underwent to acute restraint stress for 3h. The contractile response evoked by angiotensin II was increased in carotid arteries from diabetic rats. Acute restraint stress did not alter angiotensin II-induced contraction in carotid arteries from normoglycaemic rats. However acute stress combined with Diabetes increased angiotensin II-induced contraction in carotid rings. Western blot experiments and the inhibition of nitric oxide synthases in functional assays showed that neuronal, endothelial and inducible nitric oxide synthase isoforms contribute to the increased formation of peroxynitrite and contractile hyperreactivity to angiotensin II in carotid rings from stressed diabetic rats. In summary, these findings suggest that the increased superoxide anion generation in carotid arteries from diabetic rats associated to the increased local nitric oxide synthases expression and activity induced by acute restrain stress were responsible for exacerbating the local formation of peroxynitrite and the contraction induced by angiotensin II.

Hormetic and regulatory effects of lipid peroxidation mediators in pancreatic beta cells

Nutrient sensing mechanisms of carbohydrates, amino acids and lipids operate distinct pathways that are essential for the adaptation to varying metabolic conditions. The role of nutrient-induced biosynthesis of hormones is paramount for attaining metabolic homeostasis in the organism. Nutrient overload attenuate key metabolic cellular functions and interfere with hormonal-regulated inter- and intra-organ communication, which may ultimately lead to metabolic derangements. Hyperglycemia and high levels of saturated free fatty acids induce excessive production of oxygen free radicals in tissues and cells. This phenomenon, which is accentuated in both type-1 and type-2 diabetic patients, has been associated with the development of impaired glucose tolerance and the etiology of peripheral complications. However, low levels of the same free radicals also induce hormetic responses that protect cells against deleterious effects of the same radicals. Of interest is the role of hydroxyl radicals in initiating peroxidation of polyunsaturated fatty acids (PUFA) and generation of α,β-unsaturated reactive 4-hydroxyalkenals that avidly form covalent adducts with nucleophilic moieties in proteins, phospholipids and nucleic acids. Numerous studies have linked the lipid peroxidation product 4-hydroxy-2E-nonenal (4-HNE) to different pathological and cytotoxic processes. Similarly, two other members of the family, 4-hydroxyl-2E-hexenal (4-HHE) and 4-hydroxy-2E,6Z-dodecadienal (4-HDDE), have also been identified as potential cytotoxic agents. It has been suggested that 4-HNE-induced modifications in macromolecules in cells may alter their cellular functions and modify signaling properties. Yet, it has also been acknowledged that these bioactive aldehydes also function as signaling molecules that directly modify cell functions in a hormetic fashion to enable cells adapt to various stressful stimuli. Recent studies have shown that 4-HNE and 4-HDDE, which activate peroxisome proliferator-activated receptor δ (PPARδ) in vascular endothelial cells and insulin secreting beta cells, promote such adaptive responses to ameliorate detrimental effects of high glucose and diabetes-like conditions. In addition, due to the electrophilic nature of these reactive aldehydes they form covalent adducts with electronegative moieties in proteins, phosphatidylethanolamine and nucleotides. Normally these non-enzymatic modifications are maintained below the cytotoxic range due to efficient cellular neutralization processes of 4-hydroxyalkenals. The major neutralizing enzymes include fatty aldehyde dehydrogenase (FALDH), aldose reductase (AR) and alcohol dehydrogenase (ADH), which transform the aldehyde to the corresponding carboxylic acid or alcohols, respectively, or by biding to the thiol group in glutathione (GSH) by the action of glutathione-S-transferase (GST). This review describes the hormetic and cytotoxic roles of oxygen free radicals and 4-hydroxyalkenals in beta cells exposed to nutritional challenges and the cellular mechanisms they employ to maintain their level at functional range below the cytotoxic threshold.

[The role of inflammation in the pathogenesis of chronic heart failure]

The review considers the main points of the concept of progressive chronic heart failure (CHF). The neurohumoral model of CHF pathogenesis could create novel approaches to treating these patients. However, recent studies have shown that the ways of activating the neurohumoral systems in CHF are much more complex. The increased local synthesis of hormones causes the activation of proinflammatory cytokines and proto-oncogenes, which have a number of negative effects. Multiple studies have formulated the immunoinflammatory concept of CHF pathogenesis, according to which the increased concentration of interleukin-6 is a marker of poor prognosis in CHF, and the level of tumor necrosis factor-α directly correlates with the severity of its clinical manifestations and the activity of the neurohumoral background in decompensation. The review gives a classification of cytokines and describes the reasons for their elevated plasma concentration, their possible role in the occurrence and progression of CHF, and their prognostic significance. The pathogenesis of CHF, which includes cytokine aggression, requires further studies of the effect of the inflammatory component on the course of heart failure.

Effects of nitric oxide on stem cell therapy

The use of stem cells as a research tool and a therapeutic vehicle has demonstrated their great potential in the treatment of various diseases. With unveiling of nitric oxide synthase (NOS) universally present at various levels in nearly all types of body tissues, the potential therapeutic implication of nitric oxide (NO) has been magnified, and thus scientists have explored new treatment strategies involved with stem cells and NO against various diseases. As the functionality of NO encompasses cardiovascular, neuronal and immune systems, NO is involved in stem cell differentiation, epigenetic regulation and immune suppression. Stem cells trigger cellular responses to external signals on the basis of both NO specific pathways and concerted action with endogenous compounds including stem cell regulators. As potency and interaction of NO with stem cells generally depend on the concentrations of NO and the presence of the cofactors at the active site, the suitable carriers for NO delivery is integral for exerting maximal efficacy of stem cells. The innovative utilization of NO functionality and involved mechanisms would invariably alter the paradigm of therapeutic application of stem cells. Future prospects in NO-involved stem cell research which promises to enhance drug discovery efforts by opening new era to improve drug efficacy, reduce drug toxicity and understand disease mechanisms and pathways, were also addressed.

α-Lipoic acid protects kidney from oxidative stress and mitochondrial dysfunction associated to inflammatory conditions

An adequate redox status is important for maintaining mitochondrial function in inflammatory conditions. The aim of this work was to evaluate the effects of α-lipoic acid (LA) in kidney oxidative metabolism and mitochondrial function in lipopolysaccharide (LPS) treated rats. Sprague-Dawley rats (female, 45 ± 5 days old) were treated with LPS (10 mg kg(-1)) and/or LA (100 mg kg(-1)). It was observed in LPS-treated animals that the LA prevented the increase in 1.2 fold of NO production, decreased (30-40%) mitochondrial complex I-III and IV activities, and decreased (26%) membrane potential and cardiolipin oxidation (76%). No differences were observed in mitochondrial O2 consumption, mitochondrial complex II-III activity, and ATP production when LPS group was compared to LA + LPS group. Based on the improvement of mitochondrial function, the decreased production of mitochondrial NO and restoration of cardiolipin levels, this work provides a new evidence that α-lipoic acid protects kidney from oxidative stress and mitochondrial dysfunction.

Glutathione Supplementation Attenuates Oxidative Stress and Improves Vascular Hyporesponsiveness in Experimental Obstructive Jaundice

We investigated the protective effects and mechanism of glutathione (GSH) on vascular hyporesponsiveness induced by bile duct ligation (BDL) in a rat model. Seventy-two male Sprague-Dawley rats were randomly divided into four groups: a NS group, a GSH group, a BDL + NS group, and a BDL + GSH group. GSH was administrated into rats in the GSH and BDL + GSH groups by gastric gavage. An equal volume of normal saline was, respectively, given in the NS group and BDL + NS group. Blood was gathered for serological determination and thoracic aorta rings were isolated for measurement of isometric tension. Obstructive jaundice led to a significant increase in the serum total bilirubin, AST, and ALT levels. The proinflammatory cytokines levels (TNF-α and IL-1β), concentration of NO, and oxidative stress markers (MDA and 3-NT) were increased as well. All of those were reduced by the treatment of GSH. Meanwhile, contraction of aorta rings to NA and vasorelaxation to ACh or SNP in the BDL group rats were markedly decreased, while GSH administration reversed this change. Our findings suggested that GSH supplementation attenuated overexpressed ONOO(−) from the reaction of excessive NO with O₂^∙- and protected against obstructive jaundice-induced vascular hyporesponsiveness in rats.

Low SOD activity is associated with overproduction of peroxynitrite and nitric oxide in patients with acute coronary syndrome

OBJECTIVE

The present study was undertaken to evaluate the variation of the oxidative/nitrosative stress status in a population of subjects; with acute coronary syndrome (ACS), and examine its possible implication in plaque rupture which is the main mechanism in the pathophysiology of ACS.

PATIENTS AND METHODS

We made this study on 50 men with ACS and 50 age and sex matched healthy controls. Nitrosative/oxidative stress markers including; nitric oxide, superoxide anion levels, superoxide dismutase (SOD) activity and peroxynitrite levels were evaluated in blood samples of patients and controls.

RESULTS

Compared with healthy subjects, coronary patients had significantly higher nitric oxide, peroxynitrite and superoxide anion concentrations in both plasma and erythrocytes associated to significant decrease of SOD activity. Erythrocytes peroxynitrite concentration was negatively correlated with the antioxidant enzyme activity (SOD).

CONCLUSION

Our results show a significant accumulation of both intracellular and plasma pro-oxidants with a concomitant decrease in the SOD scavenging activity in ACS patients. Both seem to be associated with plaque rupture and ischemia observed in ACS.

Nitric oxide dysregulation in patients with heart failure: the association of depressive symptoms with L-arginine, asymmetric dimethylarginine, symmetric dimethylarginine, and isoprostane

OBJECTIVE

Nitric oxide (NO) regulation plays a critical role in cardiovascular diseases including heart failure (HF). Markers of NO dysregulation have been found in individuals with depression without cardiovascular disease. Because depression is associated with poor HF outcomes, the present study tested the hypothesis that depression is associated with a dysregulated NO pathway in patients with HF.

METHODS

Serum levels of NO regulation (L-arginine, asymmetric dimethylarginine [ADMA], and symmetric dimethylarginine [SDMA]) and oxidative stress (isoprostane 8-epi prostaglandin F2α) were measured in 104 patients with HF (mean [standard deviation] age = 65.7 [8.4] years, 28% women) at baseline and 12 months. Depressive symptoms were measured using the Beck Depression Inventory. The associations between depressive symptoms with markers of NO regulation were examined with mixed-model analysis, adjusted for age, sex, time of assessment, left ventricular ejection fraction, creatinine, and hypertension.

RESULTS

Depressive symptoms were correlated with a lower L-arginine/ADMA ratio (r = -0.22, p = .003) and higher SDMA levels (r = 0.28, p < .001). Associations were similar for somatic depressive symptoms and cognitive-affective symptoms (L-arginine/ADMA ratio: r = -0.20 [p = .009] versus r = -0.19 [p = .013]; ADMA: r = 0.16 [p = .043] versus r = 0.10 [p = .20]; SDMA: r = 0.27 [p < .001] versus r = 0.22 [p = .005], respectively). No associations were found between depressive symptoms and isoprostane. The association between depression and the L-arginine/ADMA ratio remained significant in multivariate adjusted models.

CONCLUSIONS

Depressive symptoms were associated with markers of NO dysregulation, particularly the L-arginine/ADMA ratio and SDMA, in patients with HF. The lower L-arginine/ADMA ratio indicates less available NO, suggesting that NO-related endothelial dysfunction may play a role in the adverse risk of HF progression associated with depression.

Potential of garlic (Allium sativum) in lowering high blood pressure: mechanisms of action and clinical relevance

Garlic supplements have shown promise in the treatment of uncontrolled hypertension, lowering blood pressure (BP) by about 10 mmHg systolic and 8 mmHg diastolic, similar to standard BP medication. Aged garlic extract, which contains S-allylcysteine as the bioactive sulfur compound, in particular is standardizable and highly tolerable, with little or no known harmful interaction when taken with other BP-reducing or blood-thinning medication. Here we describe biologically plausible mechanisms of garlic's BP-lowering effect. Garlic-derived polysulfides stimulate the production of the vascular gasotransmitter hydrogen sulfide (H2S) and enhance the regulation of endothelial nitric oxide (NO), which induce smooth muscle cell relaxation, vasodilation, and BP reduction. Several dietary and genetic factors influence the efficiency of the H2S and NO signaling pathways and may contribute to the development of hypertension. Sulfur deficiency might play a part in the etiology of hypertension, and could be alleviated with supplementation of organosulfur compounds derived from garlic.

Antioxidant effect of carnosine treatment on renal oxidative stress in streptozotocin-induced diabetic rats

Nitric oxide (NO) plays a significant role in the development of diabetic nephropathy. We investigated the effects of an antioxidant, carnosine, on streptozotocin (STZ)-induced renal injury in diabetic rats. We used four groups of eight rats: group 1, control; group 2, carnosine treated; group 3, untreated diabetic; group 4, carnosine treated diabetic. Kidneys were removed and processed, and sections were stained with periodic acid-Schiff (PAS) and subjected to eNOS immunohistochemistry. Examination by light microscopy revealed degenerated glomeruli, thickened basement membrane and glycogen accumulation in the tubules of diabetic kidneys. Carnosine treatment prevented the renal morphological damage caused by diabetes. Moreover, administration of carnosine decreased somewhat the oxidative damage of diabetic nephropathy. Appropriate doses of carnosine might be a useful therapeutic option to reduce oxidative stress and associated renal injury in diabetes mellitus.