Low-Dose 4-Hydroxy-2-Nonenal (HNE) Reperfusion Therapy Displays Cardioprotective Effects in Mice After Myocardial Infarction That Are Abrogated by Genipin

Protective effect and possible mechanisms of geniposide for ischemia-reperfusion injury: A systematic review with meta-analysis and network pharmacology of preclinical evidence

Background

Geniposide, as a pharmacologically bioactive component, is derived from a classic and common Chinese herb, Gardenia jasminoides Ellis. Geniposide has been shown to be effective for treating I/R injury in recent studies. Current effectively pharmaceutical treatments are scarce, and treatment based on geniposide may become a novel option. As far as we know, this research is the initial systematic evaluation of the protective effects of geniposide in I/R injury.

Aim of the study

This study is engrossed in evaluating the mechanism of action of geniposide in I/R injury through a preclinical systematic review with meta-analysis and network pharmacology.

Materials and methods

We built a systematic review which provided a view of effect and mechanism of geniposide for I/R injury. Based on seven databases, an open-ended search from their inception to August 31st, 2022, was conducted. Animal studies on the effects of geniposide in I/R injury were considered. The data was analyzed using Review Manager 5.3, and bias was assessed using the CAMARADES 10-item scale. 13 articles including 279 animals were selected finally. And network pharmacology was joined to elucidate the mechanism.

Results

According to the meta-analysis, in I/R injury, geniposide can attenuate cardiomyocytes viability and the size of MI, decrease the volume of cerebral infraction and neurological score, decrease serum ALT and AST activity, and downregulated serum Cr and BUN. The review found that geniposide protects against I/R injury by inhibiting apoptosis, oxidation, inflammation and improvement of autophagy and mitochondrial respiration, which is consistent with the results of the network pharmacology screening.

Conclusion

This preclinical systematic review including meta-analysis and network pharmacology, which was the first one summarizing the relationship between geniposide and ischemia diseases, shows a novel therapy for I/R injury and appears an enticing implication of geniposide in I/R injury, and further research is looked forward. Given the restricted quantity of included researches and the unclear risk of bias of the studies, we should interpret the results with caution.

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.

POTENTIAL CARDIOPROTECTIVE EFFECT OF GENIPIN VIA CYCLOOXIDASE 2 SUPPRESSION AND P53 SIGNAL PATHWAY ATTENUATION IN INDUCED MYOCARDIAL INFARCTION IN RATS

ABSTRACT

Background and aims: Genipin, an iridoid derived from geniposide by β-glucosidase hydrolysis, has shown potential benefit in the treatment of heart function insufficiency despite its unclear therapeutic mechanism. This study aimed to investigate the primary cardioprotective mechanism of genipin. We hypothesized that genipin demonstrated the antiapoptosis and anti-inflammation for cardiac protection by inhibiting the cyclooxidase 2 (COX2)-prostaglandin D2 (PGD2) and murine double minute 2 (MDM2)-p53 pathways. Methods: The normal Sprague-Dawley rats were made into myocardial infarction models by conventional methods. Animals were treated with genipin for 5 weeks after myocardial infarction (MI). Morphometric and hemodynamic measurements were performed 5 weeks post-MI. Biological and molecular experiments were performed after the termination. Results: Both morphometry and hemodynamics in systole and diastole were significantly impaired in the model group but restored close to basal level after treatment with genipin. Genipin also restored the post-MI upregulated expressions of cytochrome c, p53, COX2, and PGD2 and downregulated expression of MDM2 to the approximate baseline. Genipin inhibited apoptotic and inflammatory pathways to prevent post-MI structure-function remodeling. Conclusions: This study showed the cardioprotective mechanism of genipin and implied its potential clinical application for the treatment of ischemic heart failure.

In silico Characterization of the Heme Oxygenase 1 From Bottlenose Dolphin (Tursiops truncatus): Evidence of Changes in the Active Site and Purifying Selection

Cetacea is a clade well-adapted to the aquatic lifestyle, with diverse adaptations and physiological responses, as well as a robust antioxidant defense system. Serious injuries caused by boats and fishing nets are common in bottlenose dolphins (Tursiops truncatus); however, these animals do not show signs of serious infections. Evidence suggests an adaptive response to tissue damage and associated infections in cetaceans. Heme oxygenase (HO) is a cytoprotective protein that participates in the anti-inflammatory response. HO catalyzes the first step in the oxidative degradation of the heme group. Various stimuli, including inflammatory mediators, regulate the inducible HO-1 isoform. This study aims to characterize HO-1 of the bottlenose dolphin in silico and compare its structure to the terrestrial mammal protein. Upstream HO-1 sequence of the bottlenose dolphin was obtained from NCBI and Ensemble databases, and the gene structure was determined using bioinformatics tools. Five exons and four introns were identified, and proximal regulatory elements were detected in the upstream region. The presence of 10 α-helices, three 310 helices, the heme group lodged between the proximal and distal helices, and a histidine-25 in the proximal helix serving as a ligand to the heme group were inferred for T. truncatus. Amino acid sequence alignment suggests HO-1 is a conserved protein. The HO-1 "fingerprint" and histidine-25 appear to be fully conserved among all species analyzed. Evidence of positive selection within an α-helix configuration without changes in protein configuration and evidence of purifying selection were found, indicating evolutionary conservation of the coding sequence structure.

Natural Tolerance to Ischemia and Hypoxemia in Diving Mammals: A Review

Reperfusion injury follows ischemia/reperfusion events occurring during myocardial infarction, stroke, embolism, and other peripheral vascular diseases. Decreased blood flow and reduced oxygen tension during ischemic episodes activate cellular pathways that upregulate pro-inflammatory signaling and promote oxidant generation. Reperfusion after ischemia recruits inflammatory cells to the vascular wall, further exacerbating oxidant production and ultimately resulting in cell death, tissue injury, and organ dysfunction. Diving mammals tolerate repetitive episodes of peripheral ischemia/reperfusion as part of the cardiovascular adjustments supporting long duration dives. These adjustments allow marine mammals to optimize the use of their body oxygen stores while diving but can result in selectively reduced perfusion to peripheral tissues. Remarkably, diving mammals show no apparent detrimental effects associated with these ischemia/reperfusion events. Here, we review the current knowledge regarding the strategies marine mammals use to suppress inflammation and cope with oxidant generation potentially derived from diving-induced ischemia/reperfusion.

Hydromorphine postconditioning protects isolated rat heart against ischemia-reperfusion injury via activating P13K/Akt/eNOS signaling

INTRODUCTION

Myocardial ischemia/reperfusion injury (myocardial I/R injury) has a high disability rate and mortality. Novel treatments for myocardial I/R injury are necessary.

AIM

In order to explore the protective effect of hydromorphine on myocardial I/R injury, we illuminate the underlying mechanism of the protective effect.

RESULTS

Hydromorphine significantly reduced myocardial infarct size (IFN/AAR), CKMB (Creatine Kinase MB) and TN-T (Troponin T) release, and improved cardiac function compared with I/R group. However, these advantageous effects were partly suppressed in the presence of hydromorphine. Myocardial I/R injury significantly decreased the phosphorylation of Akt and eNOS, and down-regulated total nitric oxide and nitrotyrosine content, while these inhibitory effects were partly abolished by hydromorphine. Conversely, the activated effects of hydromorphine on the phosphorylation of Akt and eNOS, and NO release were totally reversed by LY294002, which, used individually, show the same influence on reperfusion injury.

CONCLUSIONS

These findings suggest that hydromorphine postconditioning may protect isolated rat heart against reperfusion injury via activating P13K/Akt/eNOS signaling.

The Role of Peroxiredoxin 6 in Cell Signaling

Peroxiredoxin 6 (Prdx6, 1-cys peroxiredoxin) is a unique member of the peroxiredoxin family that, in contrast to other mammalian peroxiredoxins, lacks a resolving cysteine and uses glutathione and π glutathione S-transferase to complete its catalytic cycle. Prdx6 is also the only peroxiredoxin capable of reducing phospholipid hydroperoxides through its glutathione peroxidase (Gpx) activity. In addition to its peroxidase activity, Prdx6 expresses acidic calcium-independent phospholipase A₂ (aiPLA₂) and lysophosphatidylcholine acyl transferase (LPCAT) activities in separate catalytic sites. Prdx6 plays crucial roles in lung phospholipid metabolism, lipid peroxidation repair, and inflammatory signaling. Here, we review how the distinct activities of Prdx6 are regulated during physiological and pathological conditions, in addition to the role of Prdx6 in cellular signaling and disease.