Inducible and endothelial nitric oxide synthase expression in human atherogenesis: an immunohistochemical and ultrastructural study

Metabolic syndrome is negatively associated with cognition among endothelial nitric oxide synthase (eNOS)- 786C carriers in schizophrenia-spectrum disorders

Although metabolic syndrome and cognitive inefficiencies are well-described common complications of schizophrenia, their association remains inconsistent, potentially due to poorly understood mechanisms underlying their relationship. Variability in the endothelial nitric oxide synthase (eNOS) gene, specifically the T-786C variant, has been separately associated with cognition and metabolic syndrome, with worse outcomes for eNOS-786C carriers likely occurring via negative effects on blood vessel functioning. However, the interaction between eNOS and metabolic syndrome in cognition among adults with schizophrenia is unknown. This study aimed to test the main and interaction effects of the eNOS-786C allele in cognition using hierarchical regression analyses controlling for age, sex, education, race, and antipsychotic exposure. Metabolic syndrome, eNOS T-786C genotype, and cognitive performance were assessed in 226 community-dwelling participants with chronic schizophrenia-spectrum disorders. Results demonstrated a significant interaction between metabolic syndrome and the eNOS-786C allele. Specifically, among eNOS-786C carriers only, metabolic syndrome was independently associated with lower scores in processing speed and verbal fluency, and predicted 12.5% and 15.8% of variance in performance, respectively. These results suggest that the additive negative effects of eNOS-786C and metabolic syndrome on blood vessel functioning may be severe enough to negatively impact cognition. The finding that metabolic syndrome is associated with worse cognition only in the presence of the eNOS-786C allele may clarify extant inconsistencies in the literature. These findings provide preliminary evidence that may inform interventions to reduce cognitive morbidity among adults with schizophrenia.

Poly(ADP-ribose) Polymerase (PARP) and PARP Inhibitors: Mechanisms of Action and Role in Cardiovascular Disorders

Poly(ADP-ribosyl)ation is an immediate cellular repair response to DNA damage and is catalyzed primarily by poly(ADP-ribose)polymerase-1 (PARP1), which is the most abundant of the 18 different PARP isoforms and accounts for more than 90% of the catalytic activity of PARP in the cell nucleus. Upon detection of a DNA strand break, PARP1 binds to the DNA, cleaves nicotinamide adenine dinucleotide between nicotinamide and ribose and then modifies the DNA nuclear acceptor proteins by formation of a bond between the protein and the ADP-ribose residue. This generates ribosyl-ribosyl linkages that act as a signal for other DNA-repairing enzymes and DNA base repair. Extensive DNA breakage in cells results in excessive activation of PARP with resultant depletion of the cellular stores of nicotinamide adenine dinucleotide (NAD+) which slows the rate of glycolysis, mitochondrial electron transport, and ultimately ATP formation in these cells. This paper focuses on PARP in DNA repair in atherosclerosis, acute myocardial infarction/reperfusion injury, and congestive heart failure and the role of PARP inhibitors in combating the effects of excessive PARP activation in these diseases. Free oxygen radicals and nitrogen radicals in arteries contribute to disruption of the vascular endothelial glycocalyx, which increase the permeability of the endothelium to inflammatory cells and also low-density lipoproteins and the accumulation of lipid in the vascular intima. Mild inflammation and DNA damage within vascular cells promote PARP1 activation and DNA repair. Moderate DNA damage induces caspase-dependent PARP cleavage and vascular cell apoptosis. Severe DNA damage due to vascular inflammation causes excessive activation of PARP1. This causes endothelial cell depletion of NAD+ and ATP, downregulation of atheroprotective SIRT1, necrotic cell death, and ultimately atherosclerotic plaque disruption. Inhibition of PARP decreases vascular endothelial cell adhesion P-selectin and ICAM-1 molecules, inflammatory cells, pro-death caspase-3, and c-Jun N-terminal kinase (JNK) activation and upregulates prosurvival extracellular signal-regulated kinases and AKT, which decrease vascular cell apoptosis and necrosis and limit atherosclerosis and plaque disruption. In myocardial infarction with coronary occlusion then reperfusion, which occurs with coronary angioplasty or thrombolytic therapy, reperfusion injury occurs in as many as 31% of patients and is caused by inflammatory cells, free oxygen and nitrogen radicals, the rapid transcriptional activation of inflammatory cytokines, and the activation of PARP1. Inhibition of PARP attenuates neutrophil infiltration and inflammatory cytokine expression in the reperfused myocardium and preserves myocardial NAD+ and ATP. In addition, PARP inhibition increases the activation of myocyte survival enzymes protein kinase B (Akt) and protein kinase C epsilon (PKCε), and decreases the activity of myocardial ventricular remodeling enzymes PKCα/β, PKCζ/λ, and PKCδ. As a consequence, cardiomyocyte and vascular endothelial cell necrosis is decreased and myocardial contractility is preserved. In heart failure and circulatory shock in animal models, PARP inhibition significantly attenuates decreases in left ventricular systolic pressure, ventricular contractility and relaxation, stroke volume, and increases survival by limiting or preventing upregulation of adhesion molecules, proinflammatory cytokines, myocardial mononuclear cell infiltration, and PKCα/β and PKC λ/ζ. In this manner, PARP inhibition partially restores the myocardial concentrations of NAD+, limits ventricular remodeling and fibrosis, and prevents significant decreases in myocardial contractility. Based primarily on investigations in preclinical models of atherosclerosis, myocardial infarction, and heart failure, PARP inhibition appears to be beneficial in limiting or inhibiting cardiovascular dysfunction. These studies indicate that investigations of acute and chronic PARP inhibition are warranted in patients with atherosclerotic coronary artery disease.

The Effect of Physical Activity on Passive Leg Movement-Induced Vasodilation with Age

INTRODUCTION

Because of reduced nitric oxide (NO) bioavailability with age, passive leg movement (PLM)-induced vasodilation is attenuated in older sedentary subjects and, unlike the young subjects, cannot be augmented by posture-induced elevations in femoral perfusion pressure. However, whether vasodilator function assessed with PLM, and therefore NO bioavailability, is preserved in older individuals with greater physical activity and fitness is unknown.

METHODS

PLM was performed on four subject groups: young sedentary (Y, 23 ± 1 yr, n = 12), old sedentary (OS, 73 ± 2 yr, n = 12), old active (OA, 71 ± 2 yr, n = 10), and old endurance trained (OT, 72 ± 1 yr, n = 10) in the supine and upright-seated posture. Hemodynamics were measured using ultrasound Doppler and finger photoplethysmography.

RESULTS

In the supine posture, PLM-induced peak change in leg vascular conductance was significantly attenuated in the OS compared with the young subjects (OS = 4.9 ± 0.5, Y = 6.9 ± 0.7 mL·min·mm Hg) but was not different from the young in the OA and OT (OA = 5.9 ± 1.0, OT = 5.4 ± 0.4 mL·min·mm Hg). The upright-seated posture significantly augmented peak change in leg vascular conductance in all but the OS (OS = 4.9 ± 0.5, Y = 11.8 ± 1.3, OA = 7.3 ± 0.8, OT = 8.1 ± 0.8 mL·min·mm Hg), revealing a significant vasodilatory reserve capacity in the other groups (Y = 4.92 ± 1.18, OA = 1.37 ± 0.55, OT = 2.76 ± 0.95 mL·min·mm Hg).

CONCLUSIONS

As PLM predominantly reflects NO-mediated vasodilation, these findings support the idea that augmenting physical activity and fitness can protect NO bioavailability, attenuating the deleterious effects of advancing age on vascular function.

Expression and Subcellular Localization of Retinoic Acid Receptor-α (RARα) in Healthy and Varicocele Human Spermatozoa: Its Possible Regulatory Role in Capacitation and Survival

Varicocele, an abnormal tortuosity and dilation of veins of the pampiniform plexus, is the most common identifiable and correctable cause of male infertility. It is now becoming apparent that signaling through vitamin A metabolites, such as all-trans retinoic acid (ATRA), is indispensable for spermatogenesis and disruption of retinoic acid receptor-α (RARα) function may result in male sterility and aberrant spermatogenesis. Herein, we investigated by Western blot and immunogold electron microscopy the expression profiles and subcellular localization of RARα in healthy and varicocele human sperm; in addition, we analyzed the effects of ATRA on cholesterol efflux and sperm survival utilizing enzymatic colorimetric CHOD-PAP method and Eosin Y technique, respectively. In varicocele samples, a strong reduction of RARα expression was observed. Immunogold labeling evidenced cellular location of RARα also confirming its reduced expression in "varicocele" samples. Sperm responsiveness to ATRA treatment was reduced in varicocele sperm. Our study showed that RARα is expressed in human sperm probably with a dual role in promoting both cholesterol efflux and survival. RARα might be involved in the pathogenesis of varicocele as its expression is reduced in pathologic samples. Thus, ATRA administration in procedures for artificial insemination or dietary vitamin A supplementation might represent a promising therapeutic approach for the management of male infertility.

Interactions Between Targeted Ultrasound Contrast Agents With Anti-Human Interleukin 8 Monoclonal Antibody and Activated Endothelial Cells

The study aimed to explore the role of interleukin 8 (IL-8) in atherosclerotic plaques and develop a new method for the evaluation of endothelial function by assessing the interactions between the injured endothelial cells and the targeted ultrasound agent that carried anti-human IL-8 monoclonal antibody. Anti-human IL-8 monoclonal antibodies were associated to the shells of SonoVue microbubbles by covalent conjugation technology. The specific interaction between the microbubbles and the normal or injured endothelial cells was observed using an inverted microscope. The microbubble adherence was quantified by calculating the ratio of the adherent microbubbles to endothelial cells. The results were compared with the control microbubbles. There were rare adherences of control microbubbles to the normal or injured endothelial cells, whereas the targeted microbubbles could adhere to endothelial cells well. Importantly, compared with the normal endothelial cells, a significantly higher number of targeted microbubbles bound to the injured endothelial cells. The ultrasound agents with anti-human IL-8 monoclonal antibody can specifically bind to the injured endothelial cell, which provides a new insight to the noninvasive detection of endothelial dysfunction using ultrasound imaging techniques.

In utero oxidative stress epigenetically programs antioxidant defense capacity and adulthood diseases

SIGNIFICANCE

Maternal health and diet during gestation are critical for predicting fetal outcomes, both immediately at birth and in adulthood. While epigenetic modifications have previously been tightly linked to carcinogenesis, recent advances in the field have suggested that numerous adulthood diseases, including those characteristic of metabolic syndrome, could be programmed in utero in response to maternal exposures, and these "programmable" diseases are associated with epigenetic modifications of vital genes.

RECENT ADVANCES

While little is currently known about the epigenetic regulation of the antioxidant (AOX) defense system, several studies in animals show that AOX defense capacity may be programmed in utero, making it likely that the critical genes involved in this pathway are epigenetically regulated, either by DNA methylation or by the modification of histone tails.

CRITICAL ISSUES

This article presents the most current knowledge of the in utero regulation of the AOX defense capacity, and will specifically focus on the potential epigenetic regulation of this system in response to various in utero exposures or stimuli. The ability to appropriately respond to oxidative stress is critical for the health and survival of any organism, and the potential programming of this capacity may provide a link between the in utero environment and the tendency of certain individuals to be more susceptible toward disease stimuli in their postnatal environments.

FUTURE DIRECTIONS

We sincerely hope that future studies which result in a deeper understanding of the in utero programming of the epigenome will lead to novel and effective therapies for the treatment of epigenetically linked diseases.

Ultrastructural analysis and electron microscopic localization of Nox4 in healthy and atherosclerotic human aorta

During diverse pathological conditions, vascular smooth muscle cells (SMCs) characteristically change from a quiescent, contractile phenotype to a proliferative, synthetic state, migrate toward the intima, and synthesize excess extracellular matrix. Although reactive oxygen species (ROS) are generally considered to be toxic to cells, recent evidence suggests that they may also modulate multiple signaling pathways. The vascular system contains several sources of ROS, among which NADPH oxidases (NOXes) have been shown to take an important part in the regulation of cell function, with effects on growth and proliferation. In the present study, the authors investigate the ultrastructural features of SMCs and the expression profile of Nox4 in healthy and atherosclerotic human aorta to explore the possibility of a relationship between Nox4 and SMCs differentiation state. The data extend at the level of immunoelectron microscopy previous observations, demonstrating for the first time the precise distribution and the differential expression of Nox4 in the morphologically distinct SMC types of healthy and diseased human aorta.