Critical role for white blood cell NAD(P)H oxidase-mediated plasminogen activator inhibitor-1 oxidation and ventricular rupture following acute myocardial infarction

Revisiting pharmacology of oxidative stress and endothelial dysfunction in cardiovascular disease: Evidence for redox-based therapies

According to the latest Global Burden of Disease Study data, non-communicable diseases in general and cardiovascular disease (CVD) in particular are the leading cause of premature death and reduced quality of life. Demographic shifts, unhealthy lifestyles and a higher burden of adverse environmental factors provide an explanation for these findings. The expected growing prevalence of CVD requires enhanced research efforts for identification and characterisation of novel therapeutic targets and strategies. Cardiovascular risk factors including classical (e.g. hypertension, diabetes, hypercholesterolaemia) and non-classical (e.g. environmental stress) factors induce the development of endothelial dysfunction, which is closely associated with oxidant stress and vascular inflammation and results in CVD, particularly in older adults. Most classically successful therapies for CVD display vasoprotective, antioxidant and anti-inflammatory effects, but were originally designed with other therapeutic aims. So far, only a few 'redox drugs' are in clinical use and many antioxidant strategies have not met expectations. With the present review, we summarise the actual knowledge on CVD pathomechanisms, with special emphasis on endothelial dysfunction, adverse redox signalling and oxidative stress, highlighting the preclinical and clinical evidence. In addition, we provide a brief overview of established CVD therapies and their relation to endothelial dysfunction and oxidative stress. Finally, we discuss novel strategies for redox-based CVD therapies trying to explain why, despite a clear link between endothelial dysfunction and adverse redox signalling and oxidative stress, redox- and oxidative stress-based therapies have not yet provided a breakthrough in the treatment of endothelial dysfunction and CVD.

Knowledge of an inflammatory biomarker of cardiovascular risk leads to biomarker-based decreased risk in pre-diabetic and diabetic patients

Objective

Diabetes is a risk equivalent for cardiovascular events. The increase in vascular inflammation with diabetes is believed to be responsible for increased risk of ischemic events in diabetic patients. Our goal was to assess whether knowledge of vascular inflammation alters cardiovascular risk over time, and how knowledge of vascular inflammation changes risk in non-diabetic, pre-diabetic and diabetic patients.

Methods

We retrospectively studied >100,000 primary-care patients per annum for 5 years (baseline in 2011 through 2015) with tests including lipoprotein profile, hemoglobin A1C and the vascular-specific inflammation risk marker myeloperoxidase. Results were obtained during the patient’s MD Value In Prevention (MDVIP) annual wellness program physical.

Results

We show that rates of patients with elevated myeloperoxidase levels were reduced from 14.4%, 15.2% and 21.3% to 4.0%, 4.0% and 6.7% in non-diabetic, pre-diabetic and diabetic patients, respectively, over the 5-year period. Decreases in vascular inflammation were achieved without decreases in the prevalence of pre-diabetes (hemoglobin A1C 5.7%–6.4%) or diabetes (hemoglobin A1C >6.4%) and were observed in patients below or above guideline low-density lipoprotein targets.

Conclusions

These data demonstrate that physicians informed of elevated markers of vascular inflammation can lower vascular inflammation correlating with biomarker-based decreased risk of cardiovascular events.

Nox family NADPH oxidases in mechano-transduction: mechanisms and consequences

SIGNIFICANCE

The majority of cells in a multi-cellular organism are continuously exposed to ever-changing physical forces. Mechano-transduction links these events to appropriate reactions of the cells involving stimulation of signaling cascades, reorganization of the cytoskeleton and alteration of gene expression.

RECENT ADVANCES

Mechano-transduction alters the cellular redox balance and the formation of reactive oxygen species (ROS). Nicotine amide adenine dinucleotide reduced form (NADPH) oxidases of the Nox family are prominent ROS generators and thus, contribute to this stress-induced ROS formation.

CRITICAL ISSUES

Different types and patterns of mechano-stress lead to Nox-dependent ROS formation and Nox-mediated ROS formation contributes to cellular responses and adaptation to physical forces. Thereby, Nox enzymes can mediate vascular protection during physiological mechano-stress. Despite this, over-activation and induction of Nox enzymes and a subsequent substantial increase in ROS formation also promotes oxidative stress in pathological situations like disturbed blood flow or extensive stretch.

FUTURE DIRECTIONS

Individual protein targets of Nox-mediated redox-signaling will be identified to better understand the specificity of Nox-dependent ROS signaling in mechano-transduction. Nox-inhibitors will be tested to reduce cellular activation in response to mechano-stimuli.

Bone marrow SSEA1+ cells support the myocardium in cardiac pressure overload

RATIONALE

Stage specific embryonic antigen 1+ (SSEA1+) cells have been described as the most primitive mesenchymal progenitor cell in the bone marrow. Cardiac injury mobilizes SSEA1+ cells into the peripheral blood but their in vivo function has not been characterized.

OBJECTIVE

We generated animals with chimeric bone marrow to determine the fate and function of bone marrow SSEA1+ cells in response to acute cardiac pressure overload.

METHODS AND RESULTS

Lethally irradiated mice were transplanted with normal bone marrow where the wild-type SSEA1+ cells were replaced with green fluorescent protein (GFP) SSEA1+ cells. Cardiac injury was induced by trans-aortic constriction (TAC). We identified significant GFP+ cell engraftment into the myocardium after TAC. Bone marrow GFP+ SSEA1 derived cells acquired markers of endothelial lineage, but did not express markers of c-kit+ cardiac progenitor cells. The function of bone marrow SSEA1+ cells after TAC was determined by transplanting lethally irradiated mice with bone marrow depleted of SSEA1+ cells (SSEA1-BM). The cardiac function of SSEA1-BM mice declined at a greater rate after TAC compared to their complete bone marrow transplant counterparts and was associated with decreased bone marrow cell engraftment and greater vessel rarefication in the myocardium.

CONCLUSIONS

These results provide evidence for the recruitment of endogenous bone marrow SSEA1+ cells to the myocardium after TAC. We demonstrate that, in vivo, bone marrow SSEA1+ cells have the differentiation potential to acquire endothelial lineage markers. We also show that bone marrow SSEA1+ deficiency is associated with a reduced compensatory capacity to cardiac pressure overload, suggesting their importance in cardiac homeostasis. These data demonstrate that bone marrow SSEA1+ cells are critical for sustaining vascular density and cardiac repair to pressure overload.

Multimarker approach for identifying and documenting mitigation of cardiovascular risk

The widespread use of lipids to define risk has been a success based on the dramatic decrease in the incidence of transmural myocardial infarctions. This success and the fact that many patients with normal lipid levels go on to have acute coronary syndrome have led to investigations on the use of nonlipid-based inflammatory biomarkers to predict risk. Interestingly, as the physiology reflected by distinct biomarkers is better understood, there is increasing interest in multimarker approaches to determine risk and where a given patient may be on a spectrum of risk. In this perspective, we review data from over 95,000 patients who had a multimarker annual wellness panel to demonstrate the utility of multiple markers in defining those patients at risk. We discuss a novel multimarker panel for cardiovascular risk, define the differences between a multimarker approach and expensive amalgamations of multiple markers, and discuss how the field may develop in the future.

Extracellular signal-regulated kinase 1/2 activation is involved in intermedin1-53 attenuating myocardial oxidative stress injury induced by ischemia/reperfusion

Intermedin (IMD)(1-53) is a novel member of the calcitonin gene-related peptide superfamily and has potent cardioprotective effects against myocardial injury induced by ischemia-reperfusion (I/R). To explore the mechanism of the IMD(1-53) cardioprotective effect, we studied the anti-oxidant effects of IMD(1-53) on myocardial injury induced by I/R in vivo in rat and H(2)O(2) treatment in vitro in rat cardiomyocytes. Compared with sham treatment, I/R treatment induced severe lipid peroxidation injury in rat myocardium: plasma malondialdehyde (MDA) content and myocardial LDH activity was increased by 34% and 85% (all P<0.01); Mn-superoxide dismutase (Mn-SOD) and catalase (CAT) activity was reduced 80% and 86% (all P<0.01), respectively, and the protein levels of the NADPH oxidase complex subunits gp91(phox) and p47(phox) were markedly increased, by 86% (P<0.05) and 95% (P<0.01), respectively; IMD(1-53) treatment ameliorated lipid peroxidation injury: plasma MDA content and myocardial LDH activity was decreased by 30% (P<0.05) and 36% (P<0.01); Mn-SOD and CAT activity was elevated 1.0- and 4.3-fold (all P<0.01), respectively; and the protein levels of gp91(phox) and p47(phox) were reduced, by 28% and 36% (both P<0.05), respectively. Concurrently, IMD(1-53) treatment markedly promoted cell viability and inhibited apoptosis in cardiomyocytes as compared with H(2)O(2) treatment alone. Furthermore, IMD(1-53) increased the ratio of p-ERK to ERK by 66% (P<0.05) as compared with I/R alone, and the protective effect of IMD(1-53) on H(2)O(2)-induced apoptosis was abolished by preincubation with PD98059, a MEK inhibitor. IMD(1-53) may improve the oxidative stress injury induced by I/R via inhibiting the production of reactive oxygen species and enhancing ERK phosphorylation.