Chronic treatment with apelin, losartan and their combination reduces myocardial infarct size and improves cardiac mechanical function

Targeting the apelin system for the treatment of cardiovascular diseases

Cardiovascular disease is the leading cause of death worldwide. Its prevalence is rising due to ageing populations and the increasing incidence of diseases such as chronic kidney disease, obesity, and diabetes that are associated with elevated cardiovascular risk. Despite currently available treatments, there remains a huge burden of cardiovascular disease-associated morbidity for patients and healthcare systems, and newer treatments are needed. The apelin system, comprising the apelin receptor and its two endogenous ligands apelin and elabela, is a broad regulator of physiology that opposes the actions of the renin-angiotensin and vasopressin systems. Activation of the apelin receptor promotes endothelium-dependent vasodilatation and inotropy, lowers blood pressure, and promotes angiogenesis. The apelin system appears to protect against arrhythmias, inhibits thrombosis, and has broad anti-inflammatory and anti-fibrotic actions. It also promotes aqueous diuresis through direct and indirect (central) effects in the kidney. Thus, the apelin system offers therapeutic promise for a range of cardiovascular, kidney, and metabolic diseases. This review will discuss current cardiovascular disease targets of the apelin system and future clinical utility of apelin receptor agonism.

Carvacrol decreases blood-brain barrier permeability post-diffuse traumatic brain injury in rats

Previously, we showed that Satureja Khuzestanica Jamzad essential oil (SKEO) and its major component, carvacrol (CAR), 5-isopropyl-2-methylphenol, has anti-inflammatory, anti-apoptotic, and anti-edematous properties after experimental traumatic brain injury (TBI) in rats. CAR, predominantly found in Lamiaceae family (Satureja and Oregano), is lipophilic, allowing diffusion across the blood-brain barrier (BBB). These experiments test the hypothesis that acute treatment with CAR after TBI can attenuate oxidative stress and BBB permeability associated with CAR's anti-edematous traits. Rats were divided into six groups and injured using Marmarou weight drop: Sham, TBI, TBI + Vehicle, TBI + CAR (100 and 200 mg/kg) and CAR200-naive treated rats. Intraperitoneal injection of vehicle or CAR was administered thirty minutes after TBI induction. 24 h post-injury, brain edema, BBB permeability, BBB-related protein levels, and oxidative capacity were measured. Data showed CAR 200 mg/kg treatment decreased brain edema and prevented BBB permeability. CAR200 decreased malondialdehyde (MDA) and reactive oxygen species (ROS) and increased superoxide dismutase (SOD) and total antioxidative capacity (T-AOC), indicating the mechanism of BBB protection is, in part, through antioxidant activity. Also, CAR 200 mg/kg treatment suppressed matrix metalloproteinase-9 (MMP-9) expression and increased ZO-1, occludin, and claudin-5 levels. These data indicate that CAR can promote antioxidant activity and decrease post-injury BBB permeability, further supporting CAR as a potential early therapeutic intervention that is inexpensive and more readily available worldwide. However, more experiments are required to determine CAR's long-term impact on TBI pathophysiology.

APJ as Promising Therapeutic Target of Peptide Analogues in Myocardial Infarction- and Hypertension-Induced Heart Failure

The widely expressed G protein-coupled apelin receptor (APJ) is activated by two bioactive endogenous peptides, apelin and ELABELA (ELA). The apelin/ELA-APJ-related pathway has been found involved in the regulation of many physiological and pathological cardiovascular processes. Increasing studies are deepening the role of the APJ pathway in limiting hypertension and myocardial ischaemia, thus reducing cardiac fibrosis and adverse tissue remodelling, outlining APJ regulation as a potential therapeutic target for heart failure prevention. However, the low plasma half-life of native apelin and ELABELA isoforms lowered their potential for pharmacological applications. In recent years, many research groups focused their attention on studying how APJ ligand modifications could affect receptor structure and dynamics as well as its downstream signalling. This review summarises the novel insights regarding the role of APJ-related pathways in myocardial infarction and hypertension. Furthermore, recent progress in designing synthetic compounds or analogues of APJ ligands able to fully activate the apelinergic pathway is reported. Determining how to exogenously regulate the APJ activation could help to outline a promising therapy for cardiac diseases.

Satureja khuzistanica Jamzad essential oil and pure carvacrol attenuate TBI-induced inflammation and apoptosis via NF-κB and caspase-3 regulation in the male rat brain

Traumatic brain injury (TBI) causes progressive dysfunction that induces biochemical and metabolic changes that lead to cell death. Nevertheless, there is no definitive FDA-approved therapy for TBI treatment. Our previous immunohistochemical results indicated that the cost-effective natural Iranian medicine, Satureja khuzistanica Jamzad essential oil (SKEO), which consists of 94.16% carvacrol (CAR), has beneficial effects such as reducing neuronal death and inflammatory markers, as well as activating astrocytes and improving neurological outcomes. However, the molecular mechanisms of these neuroprotective effects have not yet been elucidated. This study investigated the possible mechanisms involved in the anti-inflammatory and anti-apoptotic properties of SKEO and CAR after TBI induction. Eighty-four male Wistar rats were randomly divided into six groups: Sham, TBI, TBI + Vehicle, TBI + CAR (100 and 200 mg/kg), and TBI + SKEO (200 mg/kg) groups. After establishing the "Marmarou" weight drop model, diffuse TBI was induced in the rat brain. Thirty minutes after TBI induction, SKEO & CAR were intraperitoneally injected. One day after TBI, injured rats exhibited significant brain edema, neurobehavioral dysfunctions, and neuronal apoptosis. Western blot results revealed upregulation of the levels of cleaved caspase-3, NFκB p65, and Bax/Bcl-2 ratio, which was attenuated by CAR and SKEO (200 mg/kg). Furthermore, the ELISA results showed that CAR treatment markedly prevents the overproduction of the brain pro-inflammatory cytokines, including IL-1β, TNF-α, and IL-6. Moreover, the neuron-specific enolase (NSE) immunohistochemistry results revealed the protective effect of CAR and SKEO on post-TBI neuronal death. The current study revealed that the possible neuroprotective mechanisms of SKEO and CAR might be related to (at least in part) modulating NF-κB regulated inflammation and caspase-3 protein expression. It also suggested that CAR exerts more potent protective effects than SKEO against TBI. Nevertheless, the administration of SKEO and CAR may express a novel therapeutic approach to ameliorate TBI-related secondary phase neuropathological outcomes.

Apelin Is a Prototype of Novel Drugs for the Treatment of Acute Myocardial Infarction and Adverse Myocardial Remodeling

In-hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) is 5-6%. Consequently, it is necessary to develop fundamentally novel drugs capable of reducing mortality in patients with acute myocardial infarction. Apelins could be the prototype for such drugs. Chronic administration of apelins mitigates adverse myocardial remodeling in animals with myocardial infarction or pressure overload. The cardioprotective effect of apelins is accompanied by blockage of the MPT pore, GSK-3β, and the activation of PI3-kinase, Akt, ERK1/2, NO-synthase, superoxide dismutase, glutathione peroxidase, matrix metalloproteinase, the epidermal growth factor receptor, Src kinase, the mitoK_ATP channel, guanylyl cyclase, phospholipase C, protein kinase C, the Na⁺/H⁺ exchanger, and the Na⁺/Ca²⁺ exchanger. The cardioprotective effect of apelins is associated with the inhibition of apoptosis and ferroptosis. Apelins stimulate the autophagy of cardiomyocytes. Synthetic apelin analogues are prospective compounds for the development of novel cardioprotective drugs.

Angiotensin II type 2 receptor agonist treatment of doxorubicin induced heart failure

Doxorubicin (DOX) is an anthracycline derivative used for treatment of malignancies; however, its clinical use is limited by its cardiotoxicity. We investigated the effects of angiotensin II type 2 receptor agonist compound 21 (C21) on DOX induced heart failure in rat heart. We compared C21 with losartan (LOS), an AT 1 receptor antagonist used for treating heart failure. We allocated 40 rats into five groups of eight: saline treated control group, DOX group administered a single 20 mg/kg dose of DOX, DOX + C21 group administered 0.3 mg/kg C21 for 21 days following the 20 mg/kg dose of DOX, DOX + losartan (LOS) group administered a 21 day regimen of 20 mg/kg LOS following the single dose of DOX, and a DOX + LOS + C21 group administered 0.3 mg/kg C21 and 20 mg/kg LOS for 21 days following the single dose of DOX. We assessed histopathology and conducted echocardiograpic and hemodynamic measurements. Left ventricular ejection fraction (EF) was reduced only in the DOX treated group. C21, LOS and C21 + LOS therapy prevented decreased EF due to DOX. Less histopathology was observed in the DOX + LOS + C21 group than for the other treatment groups. Application of C21 decreased DOX induced cardiac injury similar to LOS. Combined use of C21 and LOS was most beneficial for DOX induced heart failure.

Expression of miR-320 and miR-204 in myocardial infarction and correlation with prognosis and degree of heart failure

Myocardial infarction is a very dangerous cardiovascular disease with a high mortality rate under the modern developed medical technology. miRNA is a small molecule regulatory RNA discovered in recent years, which can play an important role in many cancers and other diseases. Medical data, machine learning and medical care strategies supporting the Internet of Things (IoMT) have certain applications in the treatment of myocardial infarction. However, the specific pathogenesis of myocardial infarction is still unclear. Therefore, this paper aimed to explore the expression of microRNA-320 and microRNA-204 in myocardial infarction and used the expression of microRNA-320 and microRNA-204 to predict the prognosis of patients with myocardial infarction. In order to discuss the expression of microRNA-320 and microRNA-204 in myocardial infarction in more detail. In this paper, 40 patients in the trial period were selected for clinical research, and 10 patients with normal cardiac function were selected in NHF group as control group. 10 patients with heart failure were selected as AMHF group. 10 patients with acute myocardial infarction were selected as AMNHF group. 10 patients with heart failure after old myocardial infarction were selected as OMHF group. AMHF group, AMNHF group and OMHF group were taken as the case group. This paper analyzed the difference of miR between different groups and determined that there were significant differences in the expression of miR-320 and miR-204 between different groups. Finally, the expression and prognosis of miR-320 and miR-204 in myocardial infarction were analyzed. The analysis results showed that the expression of microRNA-320 and microRNA-204 can inhibit the activity of myocardial cells. On the fifth day, the corresponding expression of microRNA-320 and microRNA-204 reduced the optical density of myocardial cells to 1.75 and 1.76, which was significantly lower than that on the first day. Moreover, excessive miR-320 expression and excessive miR-204 expression can increase the apoptosis rate of myocardial cells. The above results indicated that the high expression of microRNA-320 and microRNA-204 can be a bad prognostic factor in patients with myocardial infarction, showing that medical data, machine learning and medical care strategies supporting IoMT can play a role in the treatment of myocardial infarction. Therefore, it is urgent to understand the pathogenesis of heart failure after myocardial infarction and find new treatment schemes to improve the positive prognosis.

The Role of Apelin-APJ System in Diabetes and Obesity

Nowadays, diabetes and obesity are two main health-threatening metabolic disorders in the world, which increase the risk for many chronic diseases. Apelin, a peptide hormone, exerts its effect by binding with angiotensin II protein J receptor (APJ) and is considered to be linked with diabetes and obesity. Apelin and its receptor are widely present in the body and are involved in many physiological processes, such as glucose and lipid metabolism, homeostasis, endocrine response to stress, and angiogenesis. In this review, we summarize the literatures on the role of the Apelin-APJ system in diabetes and obesity for a better understanding of the mechanism and function of apelin and its receptor in the pathophysiology of diseases that may contribute to the development of new therapies.

The therapeutic potential of apelin in kidney disease

Chronic kidney disease (CKD) is a leading cause of global morbidity and mortality and is independently associated with cardiovascular disease. The mainstay of treatment for CKD is blockade of the renin-angiotensin-aldosterone system (RAAS), which reduces blood pressure and proteinuria and slows kidney function decline. Despite this treatment, many patients progress to kidney failure, which requires dialysis or kidney transplantation, and/or die as a result of cardiovascular disease. The apelin system is an endogenous physiological regulator that is emerging as a potential therapeutic target for many diseases. This system comprises the apelin receptor and its two families of endogenous ligands, apelin and elabela/toddler. Preclinical and clinical studies show that apelin receptor ligands are endothelium-dependent vasodilators and potent inotropes, and the apelin system has a reciprocal relationship with the RAAS. In preclinical studies, apelin regulates glomerular haemodynamics and acts on the tubule to promote aquaresis. In addition, apelin is protective in several kidney injury models. Although the apelin system has not yet been studied in patients with CKD, the available data suggest that apelin is a promising potential therapeutic target for kidney disease.

Can a Biohybrid Patch Salvage Ventricular Function at a Late Time Point in the Post-Infarction Remodeling Process?

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A simple, biohybrid patch made of polymer (PECUU) and ECM, without cellular components, was able to induce positive remodeling features when applied over chronic infarcts with severely dilated hearts and high cardiac function impairment in rats.

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The remodeling benefit was particularly notable in a subgroup of the sickest rats with very low initial ejection fraction in which the echocardiographic endpoints were found to improve after treatment.

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This technological approach may hold promise for future translation to patients in a chronic scenario.

A biohybrid patch without cellular components was implanted over large infarcted areas in severely dilated hearts. Nonpatched animals were assigned to control or losartan therapy. Patch-implanted animals responded with better morphological and functional echocardiographic endpoints, which were more evident in a subgroup of animals with very low pre-treatment ejection fraction (<35%). Patched animals also had smaller infarcts than both nonpatched groups. This simple approach could hold promise for clinical translation and be applied using minimally invasive procedures over the epicardium in a large set of patients to induce better ventricular remodeling, especially among those who are especially frail.

BPA disrupts 17‑estradiol‑mediated hepatic protection against ischemia/reperfusion injury in rat liver by upregulating the Ang II/AT1R signaling pathway

Bisphenol A (BPA), a xenoestrogen commonly used in plastics, may act as an endocrine disruptor, which indicates that BPA might be a public health risk. The present study aimed to investigate the effect of BPA on 17β-estradiol (E2)-mediated protection against liver ischemia/reperfusion (I/R) injury, and to identify the underlying mechanisms using a rat model. A total of 56 male Sprague Dawley rats were randomly divided into the following seven groups: i) Sham; ii) I/R; iii) Sham + BPA; iv) I/R + BPA; v) I/R + E2; vi) I/R + E2 + BPA; and vii) I/R + E2 + BPA + losartan [LOS; an angiotensin II (Ang II) type I receptor (ATIR) antagonist]. A rat model of hepatic I/R injury was established by inducing hepatic ischemia for 60 min followed by reperfusion for 24 h. When ischemia was induced, rats were treated with vehicle, E2, BPA or LOS. After 24 h of reperfusion, blood samples and hepatic tissues were collected for histopathological and biochemical examinations. The results suggested that 4 mg/kg BPA did not significantly alter the liver function, or Ang II and AT1R expression levels in the Sham and I/R groups. However, 4 mg/kg BPA inhibited E2-mediated hepatic protection by enhancing hepatic necrosis, and increasing the release of alanine transaminase, alkaline phosphatase and total bilirubin (P<0.05). Moreover, BPA increased serum and hepatic Ang II levels, as well as AT1R protein expression levels in the E2-treated rat model of liver I/R injury (P<0.05). LOS treatment reversed the negative effects of BPA on hepatic necrosis and liver serum marker levels, although it did not reverse BPA-mediated upregulation of serum and hepatic Ang II levels, or hepatic AT1R expression. Therefore, the present study suggested that BPA disrupted E2-mediated hepatic protection following I/R injury, but did not significantly affect healthy or I/R-injured livers; therefore, the mechanism underlying the effects of BPA may be associated with upregulation of the Ang II/AT1R signaling pathway.