The neuroprotective agent Rasagiline mesylate attenuates cardiac remodeling after experimental myocardial infarction

Immunometabolism at the Heart of Cardiovascular Disease

Immune cell function among the myocardium, now more than ever, is appreciated to regulate cardiac function and pathophysiology. This is the case for both innate immunity, which includes neutrophils, monocytes, dendritic cells, and macrophages, as well as adaptive immunity, which includes T cells and B cells. This function is fueled by cell-intrinsic shifts in metabolism, such as glycolysis and oxidative phosphorylation, as well as metabolite availability, which originates from the surrounding extracellular milieu and varies during ischemia and metabolic syndrome. Immune cell crosstalk with cardiac parenchymal cells, such as cardiomyocytes and fibroblasts, is also regulated by complex cellular metabolic circuits. Although our understanding of immunometabolism has advanced rapidly over the past decade, in part through valuable insights made in cultured cells, there remains much to learn about contributions of in vivo immunometabolism and directly within the myocardium. Insight into such fundamental cell and molecular mechanisms holds potential to inform interventions that shift the balance of immunometabolism from maladaptive to cardioprotective and potentially even regenerative. Herein, we review our current working understanding of immunometabolism, specifically in the settings of sterile ischemic cardiac injury or cardiometabolic disease, both of which contribute to the onset of heart failure. We also discuss current gaps in knowledge in this context and therapeutic implications.

Importance of Mitochondria in Cardiac Pathologies: Focus on Uncoupling Proteins and Monoamine Oxidases

On the one hand, reactive oxygen species (ROS) are involved in the onset and progression of a wide array of diseases. On the other hand, these are a part of signaling pathways related to cell metabolism, growth and survival. While ROS are produced at various cellular sites, in cardiomyocytes the largest amount of ROS is generated by mitochondria. Apart from the electron transport chain and various other proteins, uncoupling protein (UCP) and monoamine oxidases (MAO) have been proposed to modify mitochondrial ROS formation. Here, we review the recent information on UCP and MAO in cardiac injuries induced by ischemia-reperfusion (I/R) as well as protection from I/R and heart failure secondary to I/R injury or pressure overload. The current data in the literature suggest that I/R will preferentially upregulate UCP2 in cardiac tissue but not UCP3. Studies addressing the consequences of such induction are currently inconclusive because the precise function of UCP2 in cardiac tissue is not well understood, and tissue- and species-specific aspects complicate the situation. In general, UCP2 may reduce oxidative stress by mild uncoupling and both UCP2 and UCP3 affect substrate utilization in cardiac tissue, thereby modifying post-ischemic remodeling. MAOs are important for the physiological regulation of substrate concentrations. Upon increased expression and or activity of MAOs, however, the increased production of ROS and reactive aldehydes contribute to cardiac alterations such as hypertrophy, inflammation, irreversible cardiomyocyte injury, and failure.

A new approach to sepsis treatment by rasagiline: a molecular, biochemical and histopathological study

AIM

We aimed to investigate the effects of rasagiline on acute lung injury that develops in the sepsis model induced with the cecal ligation and puncture in rats.

MAIN METHODS

The rats were separated into the following six groups, Group 1: Sham, Group 2: Sham + Rasagiline 4 mg/kg, Group 3: Sepsis, Group 4: Sepsis + Rasagiline 1 mg/kg, Group 5: Sepsis + Rasagiline 2 mg/kg, Group 6: Sepsis + Rasagiline 4 mg/kg. A total of four holes were opened with a 16-gauge needle through the cecum distal to the point of ligation.

KEY FINDINGS

Rasagiline treatment increased glutathione level and superoxide dismutase activity while decreased the malondialdehyde level after the sepsis. There was a statistically significant improvement in the doses of 2 mg/kg and 4 mg/kg. Rasagiline also increased Tnf-α, IL1β, IL6, NF-κβand HMGB1 gene expressions in dose-dependent at 2 mg/kg and 4 mg/kg doses. In increased doses, rasagiline prevent the development of edema, the formation of inflammation, and hemorrhage.

SIGNIFICANCE

Rasagiline exerts both antioxidant and anti-inflammatory effects on the cecal ligation and puncture induced acute lung injury in rats.

Ubiquitin‑proteasomes are the dominant mediators of the regulatory effect of microRNA‑1 on cardiac remodeling after myocardial infarction

Patients with ischemic hearts who have refused coronary vascular reconstruction may exhibit dynamic myocardial remodeling and cardiac dysfunction. In the present study, the role of miRNA-1 and its association with the ubiquitin-proteasome system (UPS) in regulating myocardial remodeling was investigated. A myocardial infarction (MI) model was constructed and the hearts were treated with miRNA-1 antagomir, miRNA-1 lentiviral vectors and the UPS proteasome blocker bortezomib. The expression levels of miRNA-1 were evaluated using reverse transcription PCR and the abundance of the ubiquitin-proteasome protein and caspase-3 were evaluated via western blot analysis. Furthermore, the collagen volume fraction was calculated using Masson's trichrome staining, and the apoptosis index was detected via terminal deoxynucleotidyl transferase dUTP-biotin nick end labeling staining. Transforming growth factor (TGF)-β expression was assessed via immunohistochemical staining. Echocardiographic characteristics and myocardial infarct size were analyzed. miRNA-1 expression levels were found to be increased following MI. miRNA-1 antagomir administration clearly inhibited miRNA-1 expression, whereas the miRNA-1 lentiviral vector exerted the opposite effect. The levels of 19s proteasome, 20S proteasome and ubiquitin ligase E3 were decreased in the miRNA-1 antagomir group, but were significantly increased in the miRNA-1 lentiviral group; however, only 20S proteasome expression was decreased in the bortezomib group. Collagen hyperplasia and TGF-β expression were decreased in both the miRNA-1 antagomir and bortezomib groups, although the effects of the miRNA-1 antagomir were more noticeable. The miRNA-1 antagomir and the UPS proteasome blocker both alleviated the ultrastructural impairments, demonstrated by a decreased left ventricular (LV) end-diastolic diameter and LV mass, but the miRNA-1 antagomir was also able to increase LV ejection fraction and LV fractional shortening. miRNA-1 regulated UPS-associated mRNA expression and affected the majority of the UPS components in the myocardium, thereby leading to increased myocardial cell apoptosis, myocardial fibrosis and remodeling. The miRNA-1 antagomir exerted a more prominent cardioprotective effect compared with the UPS proteasome blocker bortezomib.

The neuroprotective agent Rasagiline mesylate attenuates cardiac remodeling after experimental myocardial infarction

AIM

Rasagiline mesylate (N-propargyl-1 (R)-aminoindan) (RG) is a selective, potent irreversible inhibitor of monoamine oxidase-B with cardioprotective and anti-apoptotic properties. We investigated whether it could be cardioprotective in a rat model undergoing experimental myocardial infarction (MI) by permanent ligation of the left anterior descending coronary artery.

METHODS AND RESULTS

RG was administered, intraperitoneally, for 28 days (2 mg/kg) starting 24 h after MI induction. Echocardiography analysis revealed a significant reduction in left ventricular end-systolic and diastolic dimensions and preserved fractional shortening in RG-treated compared with normal saline group at 28 days post-MI (31.6 ± 2.3 vs. 19.6 ± 1.8, P < 0.0001), respectively. Treatment with RG prevented tissue fibrosis as indicated by interstitial collagen estimation by immunofluorescence staining and hydroxyproline content and attenuated the number of apoptotic myocytes in the border zone (65%) as indicated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Caspase 3 relative protein levels were significantly decreased in the non-infarcted myocardium. Markedly decreased malondialdehyde levels in the border zone indicate a reduction in tissue oxidative stress.

CONCLUSIONS

Our study demonstrates a positive effect of RG in the post-MI period with a significant attenuation in cardiac remodelling.