Targeting the Endothelium to Achieve Cardioprotection

The sodium-glucose cotransporter 2 inhibitor tofogliflozin induces vasodilation of rabbit femoral artery by activating Kv channels, the SERCA pump, and the sGC/cGMP pathway

Tofogliflozin is a sodium-glucose cotransporter 2 inhibitor widely used to treat type 2 diabetes mellitus, but it also exhibits cardio-protective effects. This study investigated the vasodilatory action of tofogliflozin using rabbit femoral artery rings pre-contracted with phenylephrine (1 μM). The results showed the concentration-dependent induction of vasodilation by tofogliflozin, a response that remained unchanged following endothelial removal, pretreatment with the nitric oxide synthase inhibitor L-NAME (100 μM), or the inhibition of low- and intermediate-conductance Ca2+-activated K+ channels using apamin (1 μM) in combination with TRAM-34 (1 μM). Furthermore, pretreatment with the voltage-dependent K+ (Kv) channel inhibitor 4-AP (3 mM) reduced the vasodilatory effects of tofogliflozin whereas pretreatment with the ATP-sensitive K+ channel inhibitor glibenclamide (10 μM) or the large-conductance Ca2+-activated K+ channel inhibitor paxilline (1 μM) did not. Notably, our findings indicated that Kv7.X, rather than Kv1.5 or Kv2.1, is the primary Kv subtype involved in tofogliflozin-induced vasodilation. The vasodilatory effects of tofogliflozin were also significantly inhibited in femoral arterial rings pretreated with the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitors thapsigargin (1 μM) and cyclopiazonic acid (10 μM). Tofogliflozin-induced vasodilation was unaltered in arterial rings exposed to the adenylyl cyclase inhibitor SQ 22536 (50 μM), the protein kinase A (PKA) inhibitor KT 5720 (1 μM), and the protein kinase G inhibitor KT 5823 (1 μM) whereas it was effectively reduced by the soluble guanylyl cyclase (sGC) inhibitor ODQ (10 μM). These findings suggest that tofogliflozin-induced vasodilation is mediated by the activation of the SERCA pump, the sGC/cGMP pathway, and Kv channels.

Oxygen-ozone therapy for myocardial ischemic stroke and cardiovascular disorders

Cardiovascular diseases (CVDs) represent a major concern for human health worldwide. Emergencies in this field include wide repertories of studies dealing primarily with CVD prevention. In addition to dietary habits and lifestyles, medical knowledge is fully needed to improve public educational programs toward cardiovascular risk factors and to enrich the endowment of pharmaceutical options and therapies to address CVDs, particularly for ischemic damage due to an impairment in the endothelial-myocardial relationship. Because ozone is a stimulator of the endothelial nitric oxide synthase/nitric oxide pathway, ozone therapy has been widely demonstrated to have the ability to counteract endothelial-cardiac disorders, providing a novel straightforward opportunity to reduce the impact of CVDs, including atrial fibrillation. In this review, we attempt to establish a state-of-the-art method for the use of ozone in CVD, suggesting that future remarks be addressed to provide fundamental insights into this issue. The purpose of this study was to highlight the role of ozone in the adjunctive medical treatment of cardiovascular pathologies such as acute myocardial infarction due to ischemic disorders.

Endothelial Dysfunction in Acute Myocardial Infarction: A Complex Association With Sleep Health, Traditional Cardiovascular Risk Factors and Prognostic Markers

BACKGROUND

Endothelial function (EndFx) is a core component of cardiovascular (CV) health and cardioprotection following acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI).

HYPOTHESIS

AMI patients experience endothelial dysfunction (EndDys), associated with traditional CV risk factors and sleep patterns. EndFx may also predict short and mid-term outcomes.

METHODS

EndFx was assessed in 63 patients (56.2 ± 7.6 years) using the Endothelium Quality Index (EQI). Sleep quality and quantity were evaluated using objective (actigraphy) and subjective (Pittsburgh Sleep Quality Index questionnaire) measures. Cardiorespiratory fitness was quantified through the 6-min walking test. Cardiac function was assessed using the left ventricular ejection fraction.

RESULTS

Following AMI, patients tended to experience EndDys (EQI = 1.4 ± 0.7). A severe EndDys was observed in 23.8% of patients (n = 15), while a mild EndDys was present in 63.49% (n = 40). Furthermore, EndDys was significantly associated with traditional CV risk factors (i.e., low physical activity level [12.8%], age [-4.2%], and smoking [-0.7%]) (R2 adjusted = 0.50, p < 0.001). Patients with EndDys had poor sleep quality (p = 0.001) and sleep efficiency (p = 0.016) compared to healthy persons. Patients with severe EndDys exhibited lower cardiorespiratory fitness compared to those with healthy EndFx (p = 0.017). Furthermore, during a follow-up period (nearly 4 months) following PCI, major adverse cardiac events were observed in four patients with severe EndDys.

CONCLUSIONS

Our results emphasize the importance of adequate sleep and an active lifestyle, notably physical activity practice, as modifiable elements to enhance EndFx, which is regarded as a predictive tool following AMI. However, other factors remain to be elucidated as predictors of CV risk.

TRIAL REGISTRATION

The study protocol was registered in the Pan African Clinical Trial Registry under the trial ID: PACTR202208834230748.

Circulating glycocalyx shedding products as biomarkers for evaluating prognosis of patients with out-of-hospital cardiac arrest after return of spontaneous circulation

The endothelial glycocalyx is damaged in postcardiac arrest syndrome (PCAS), but the prognostic value is unknown. We aimed to observe the expression and prognostic value of glycocalyx shedding products, including syndecan-1 (SDC-1), hyaluronan (HA), and heparan sulfate (HS) in PCAS. Data on clinical and 28-day outcomes of seventy-one consecutive patients with out-of-hospital cardiac arrest (OHCA) after the return of spontaneous circulation (ROSC) were collected. SDC-1, HA, and HS were measured on days 0, 1, and 3 after ROSC. Thirty healthy individuals were controls. Glycocalyx shedding was observed in human umbilical vein endothelial cells (HUVECs) stimulated during hypoxia and reoxygenation in vitro. Within 4 h of ROSC, SDC-1 and HA levels, significantly increased. In the 28-day non-survivors, HA levels showed a gradual upward trend, SDC-1 remained at a high level, and HS levels first increased, then decreased. Kaplan-Meier curves and binary logistic regression analysis showed the prognostic value of SDC-1 levels on days 0, 1, and 3, HA levels on days 1 and 3, and HS levels on day 1. Only HS levels on day 1 showed a prognostic value for 28-day neurological outcomes. SDC-1 and HA levels were positively correlated with the no-flow time. In vitro, HUVECs showed shedding of SDC-1 and HS during a prolonged duration of hypoxia. After ROSC, SDC-1, HA, and HS levels may predict the 28-day survival after PCAS, and HS levels are associated with functional outcomes.

CB2 Cannabinoid Receptor as a Potential Target in Myocardial Infarction: Exploration of Molecular Pathogenesis and Therapeutic Strategies

The lipid endocannabinoid system has recently emerged as a novel therapeutic target for several inflammatory and tissue-damaging diseases, including those affecting the cardiovascular system. The primary targets of cannabinoids are cannabinoid type 1 (CB1) and 2 (CB2) receptors. The CB2 receptor is expressed in the cardiomyocytes. While the pathological changes in the myocardium upregulate the CB2 receptor, genetic deletion of the receptor aggravates the changes. The CB2 receptor plays a crucial role in attenuating the advancement of myocardial infarction (MI)-associated pathological changes in the myocardium. Activation of CB2 receptors exerts cardioprotection in MI via numerous molecular pathways. For instance, delta-9-tetrahydrocannabinol attenuated the progression of MI via modulation of the CB2 receptor-dependent anti-inflammatory mechanisms, including suppression of pro-inflammatory cytokines like IL-6, TNF-α, and IL-1β. Through similar mechanisms, natural and synthetic CB2 receptor ligands repair myocardial tissue damage. This review aims to offer an in-depth discussion on the ameliorative potential of CB2 receptors in myocardial injuries induced by a variety of pathogenic mechanisms. Further, the modulation of autophagy, TGF-β/Smad3 signaling, MPTP opening, and ROS production are discussed. The molecular correlation of CB2 receptors with cardiac injury markers, such as troponin I, LDH1, and CK-MB, is explored. Special attention has been paid to novel insights into the potential therapeutic implications of CB2 receptor activation in MI.

Endothelial cell dysfunction in cardiac disease: driver or consequence?

The vascular endothelium is a multifunctional cellular system which directly influences blood components and cells within the vessel wall in a given tissue. Importantly, this cellular interface undergoes critical phenotypic changes in response to various biochemical and hemodynamic stimuli, driving several developmental and pathophysiological processes. Multiple studies have indicated a central role of the endothelium in the initiation, progression, and clinical outcomes of cardiac disease. In this review we synthesize the current understanding of endothelial function and dysfunction as mediators of the cardiomyocyte phenotype in the setting of distinct cardiac pathologies; outline existing in vivo and in vitro models where key features of endothelial cell dysfunction can be recapitulated; and discuss future directions for development of endothelium-targeted therapeutics for cardiac diseases with limited existing treatment options.

Therapeutic Potential of EVs: Targeting Cardiovascular Diseases

Due to their different biological functions, extracellular vesicles (EVs) have great potential from a therapeutic point of view. They are released by all cell types, carrying and delivering different kinds of biologically functional cargo. Under pathological events, cells can increase their secretion of EVs and can release different amounts of cargo, thus making EVs great biomarkers as indicators of pathological progression. Moreover, EVs are also known to be able to transport and deliver cargo to different recipient cells, having an important role in cellular communication. Interestingly, EVs have recently been explored as biological alternatives for the delivery of therapeutics, being considered natural drug delivery carriers. Because cardiovascular disorders (CVDs) are the leading cause of death worldwide, in this review, we will discuss the up-to-date knowledge regarding the biophysical properties and biological components of EVs, focusing on myocardial infarction, diabetic cardiomyopathy, and sepsis-induced cardiomyopathy, three very different types of CVDs.

Extracellular Vesicles and Ischemic Cardiovascular Diseases

Characterized by coronary artery obstruction or stenosis, ischemic cardiovascular diseases as advanced stages of coronary heart diseases commonly lead to left ventricular aneurysm, ventricular septal defect, and mitral insufficiency. Extracellular vesicles (EVs) secreted by diverse cells in the body exert roles in cell-cell interactions and intrinsic cellular regulations. With a lipid double-layer membrane and biological components such as DNA, protein, mRNA, microRNAs (miRNA), and siRNA inside, the EVs function as paracrine signaling for the pathophysiology of ischemic cardiovascular diseases and maintenance of the cardiac homeostasis. Unlike stem cell transplantation with the potential tumorigenicity and immunogenicity, the EV-based therapeutic strategy is proposed to satisfy the demand for cardiac repair and regeneration while the circulating EVs detected by a noninvasive approach can act as precious biomarkers. In this chapter, we extensively summarize the cardioprotective functions of native EVs and bioengineered EVs released from stem cells, cardiomyocytes, cardiac progenitor cells (CPCs), endothelial cells, fibroblast, smooth muscle cells, and immune cells. In addition, the potential of EVs as robust molecule biomarkers is discussed for clinical diagnosis of ischemic cardiovascular disease, attributed to the same pathology of EVs as that of their origin. Finally, we highlight EV-based therapy as a biocompatible alternative to direct cell-based therapy for ischemic cardiovascular diseases.

Hyperuricemia and Endothelial Function: Is It a Simple Association or Do Gender Differences Play a Role in This Binomial?

The endothelium plays a fundamental role in the biological processes that ensure physiological vessel integrity, synthesizing numerous substances that are capable of modulating the tone of vessels, inflammation and the immune system, and platelet function. Endothelial dysfunction refers to an anomaly that develops at the level of the tunica that lines the internal surface of arterial and venous vessels, or, more precisely, an alteration to normal endothelial function, which involves the loss of some structural and/or functional characteristics. Studies on sex differences in endothelial function are conflicting, with some showing an earlier decline in endothelial function in men compared to women, while others show a similar age of onset between the sexes. Since increased cardiovascular risk coincides with menopause, female hormones, particularly estrogen, are generally believed to be cardioprotective. Furthermore, it is often proposed that androgens are harmful. In truth, these relationships are more complex than one might think and are not just dependent on fluctuations in circulating hormones. An increase in serum uric acid is widely regarded as a possible risk factor for cardiovascular disease; however, its role in the occurrence of endothelial dysfunction has not yet been elucidated. Several studies in the literature have evaluated sex-related differences in the association between elevated uric acid levels and cardiovascular events, with conflicting results. The association between uric acid and cardiovascular disease is still controversial, and it is not yet clear how gender differences affect the serum concentration of these substances. This review was primarily aimed at clarifying the effects of uric acid at the level of the vascular endothelium and describing how it could theoretically cause damage to endothelial integrity. The second aim was to determine if there are gender differences in uric acid metabolism and how these differences interact with the vascular endothelium.

Gender and Renal Insufficiency: Opportunities for Their Therapeutic Management?

Acute kidney injury (AKI) is a major clinical problem associated with increased morbidity and mortality. Despite intensive research, the clinical outcome remains poor, and apart from supportive therapy, no other specific therapy exists. Furthermore, acute kidney injury increases the risk of developing chronic kidney disease (CKD) and end-stage renal disease. Acute tubular injury accounts for the most common intrinsic cause of AKI. The main site of injury is the proximal tubule due to its high workload and energy demand. Upon injury, an intratubular subpopulation of proximal epithelial cells proliferates and restores the tubular integrity. Nevertheless, despite its strong regenerative capacity, the kidney does not always achieve its former integrity and function and incomplete recovery leads to persistent and progressive CKD. Clinical and experimental data demonstrate sexual differences in renal anatomy, physiology, and susceptibility to renal diseases including but not limited to ischemia-reperfusion injury. Some data suggest the protective role of female sex hormones, whereas others highlight the detrimental effect of male hormones in renal ischemia-reperfusion injury. Although the important role of sex hormones is evident, the exact underlying mechanisms remain to be elucidated. This review focuses on collecting the current knowledge about sexual dimorphism in renal injury and opportunities for therapeutic manipulation, with a focus on resident renal progenitor stem cells as potential novel therapeutic strategies.

Dicarbonyl Stress in Diabetic Vascular Disease

Late vascular complications play a prominent role in the diabetes-induced increase in morbidity and mortality. Diabetes mellitus is recognised as a risk factor driving atherosclerosis and cardiovascular mortality; even after the normalisation of blood glucose concentration, the event risk is amplified-an effect called "glycolytic memory". The hallmark of this glycolytic memory and diabetic pathology are advanced glycation end products (AGEs) and reactive glucose metabolites such as methylglyoxal (MGO), a highly reactive dicarbonyl compound derived mainly from glycolysis. MGO and AGEs have an impact on vascular and organ structure and function, contributing to organ damage. As MGO is not only associated with hyperglycaemia in diabetes but also with other risk factors for diabetic vascular complications such as obesity, dyslipidaemia and hypertension, MGO is identified as a major player in the development of vascular complications in diabetes both on micro- as well as macrovascular level. In diabetes mellitus, the detoxifying system for MGO, the glyoxalase system, is diminished, accounting for the increased MGO concentration and glycotoxic load. This overview will summarise current knowledge on the effect of MGO and AGEs on vascular function.

Cardiac Remodeling After Myocardial Infarction: Functional Contribution of microRNAs to Inflammation and Fibrosis

After an ischemic injury, the heart undergoes a complex process of structural and functional remodeling that involves several steps, including inflammatory and fibrotic responses. In this review, we are focusing on the contribution of microRNAs in the regulation of inflammation and fibrosis after myocardial infarction. We summarize the most updated studies exploring the interactions between microRNAs and key regulators of inflammation and fibroblast activation and we discuss the recent discoveries, including clinical applications, in these rapidly advancing fields.

Menopause, androgens, and cardiovascular ageing: a narrative review

Cardiovascular disease is the leading cause of death worldwide; however, women tend to be less affected than men during their reproductive years. The female cardiovascular risk increases significantly around the time of the menopausal transition. The loss of the protective action of ovarian oestrogens and the circulating androgens has been implicated in possibly inducing subclinical and overt changes in the cardiovascular system after the menopausal transition. In vitro studies performed in human or animal cell lines demonstrate an adverse effect of testosterone on endothelial cell function and nitric oxide bioavailability. Cohort studies evaluating associations between testosterone and/or dehydroepiandrosterone and subclinical vascular disease and clinical cardiovascular events show an increased risk for women with more pronounced androgenicity. However, a mediating effect of insulin resistance is possible. Data on cardiovascular implications following low-dose testosterone treatment in middle-aged women or high-dose testosterone supplementation for gender affirmatory purposes remain primarily inconsistent. It is prudent to consider the possible adverse association between testosterone and endothelial function during the decision-making process of the most appropriate treatment for a postmenopausal woman.

RAAS: A Convergent Player in Ischemic Heart Failure and Cancer

The current global prevalence of heart failure is estimated at 64.34 million cases, and it is expected to increase in the coming years, especially in countries with a medium-low sociodemographic index where the prevalence of risk factors is increasing alarmingly. Heart failure is associated with many comorbidities and among them, cancer has stood out as a contributor of death in these patients. This connection points out new challenges both in the context of the pathophysiological mechanisms involved, as well as in the quality of life of affected individuals. A hallmark of heart failure is chronic activation of the renin-angiotensin-aldosterone system, especially marked by a systemic increase in levels of angiotensin-II, a peptide with pleiotropic activities. Drugs that target the renin-angiotensin-aldosterone system have shown promising results both in the prevention of secondary cardiovascular events in myocardial infarction and heart failure, including a lower risk of certain cancers in these patients, as well as in current cancer therapies; therefore, understanding the mechanisms involved in this complex relationship will provide tools for a better diagnosis and treatment and to improve the prognosis and quality of life of people suffering from these two deadly diseases.

Extracellular vesicles (EVs) in ischemic conditioning and angiogenesis: Focus on endothelial derived EVs

During myocardial ischemia, timely reperfusion is critical to limit infarct area and the overall loss of cardiac contractile function. However, reperfusion further exacerbates the damage of the ischemic heart. This type of injury is known as ischemia-reperfusion injury (IRI). Ischemic conditioning is a procedure which consists of brief cycles of ischemia and reperfusion in order to protect the myocardium against IRI. Remote ischemic conditioning (RIC), namely transient brief episodes of ischemia at a remote site before a subsequent damaging ischemia/reperfusion procedure of the target organ (e.g., the heart), protects against IRI. However, how the stimulus of RIC is transduced from the remote organ to the ischemic heart is still unknown. Recently, extracellular vesicles (EVs) have been proposed to have a role in the RIC procedure. The endothelium releases EVs and is also one of the tissues mostly exposed to EVs during their journey to the target organ. Moreover, EVs may have important roles in angiogenesis and, therefore, in the remodeling of post-ischemic organs. Here we analyze how EVs may contribute to the overall cardioprotective effect and the implication of the endothelium and its EVs in RIC mediated acute cardioprotection as well as in angiogenesis.