| Version | Summary | Created by | Modification | Content Size | Created at | Operation |
|---|---|---|---|---|---|---|
| 1 | Diego Matías Vergara | -- | 6448 | 2022-05-06 16:25:10 | | | |
| 2 | Diego Matías Vergara | -4527 word(s) | 1921 | 2022-06-26 04:41:56 | | | | |
| 3 | Diego Matías Vergara | Meta information modification | 1921 | 2022-06-26 04:43:45 | | | | |
| 4 | Amina Yu | -368 word(s) | 1553 | 2022-06-27 04:18:42 | | | | |
| 5 | Amina Yu | Meta information modification | 1553 | 2022-06-27 04:20:31 | | |
Ischemia-reperfusion myocardial damage is a paradoxical tissue injury occurring during percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) patients. Although this damage could account for up to 50% of the final infarct size, there has been no available pharmacological treatment until now. Oxidative stress contributes to the underlying production mechanism, exerting the most marked injury during the early onset of reperfusion. So far, antioxidants have been shown to protect the AMI patients undergoing PCI to mitigate these detrimental effects; however, no clinical trials to date have shown any significant infarct size reduction. Myocardial ischemia/reperfusion damage results from diverse oxidative stress producing mechanisms.
During myocardial ischemia there is an overload in intracellular Ca2+ that cannot be captured by the Ca2+ ATPase (SERCA) in the sarcoplasmic reticulum due to the lack of ATP. The overload of Ca2+ induces enzymatic changes. One of them is the conversion of xanthine dehydrogenase in endothelial cells to xanthine oxidase (XO), an enzyme that generates superoxide anion radicals [5]. Another example is the oxidation of tetrahydrobiopterin and the subsequent uncoupling of endothelial nitric oxide synthase (eNOS), resulting in superoxide production instead of nitric oxide [6]. These changes are related to a burst in ROS production during reperfusion, overwhelming the antioxidant defenses.
There are multiple mechanisms involved in cellular damage and subsequent cellular death during the ischemia/reperfusion (I/R) process. Some of them involves endoplasmic reticulum stress, mitochondrial dysfunction, and inflammation mediated damage. This myocardial cellular injury is mediated through necrosis, apoptosis and even ferroptosis.

Resveratrol is a natural polyphenol with multiple biological activities [8]. Different one have evidenced that it has various properties, including anti-inflammatory, antioxidant, anti-diabetic, antihypertensive, anti-cancerous and cardioprotective effects [8][9]. Some of the pathways involved in its cardioprotective protective effects will be reviewed.
SIRT1 regulates oxidative stress-related proteins and other proteins that affect the function of cardiomyocytes. Resveratrol was proposed as a SIRT1 activator, resulting in a cardioprotective response via reduction of Ca2+ overload [10]. Accordingly, recent studies on mice demonstrates that resveratrol determines the increase of SIRT1 levels during I/R injury, resulting in a decrease in the incidence of atrioventricular block and letality, and a decrease of UCP-2 expression, an apoptosis mediator [8][11].
The addition of Resveratrol in cell cultures reduced oxidative stress and the content of Fe2+. The effect was explained by changes in the regulation of gene expression, in which resveratrol down-regulated transferrin receptor 1 expression and up-regulated the expression of ferritin heavy chain 1 and GPX4, leading to inhibition of ferroptosis and potentiation of the antioxidant defenses, respectively [12].
Different studies have suggested that resveratrol might inhibit apoptosis through multiple ways. One of them is the activation of PI3K/AKT signaling pathway, which down-regulates the expression of apoptotic genes and regulates cell proliferation [13][14], leading to decreased ROS levels, increased catalase and glutathione peroxidase activities, and increased cell viability [15]. Also, resveratrol could reduce caspase 3 expression [16]. Moreover, resveratrol attenuates necroptosis after I/R injury by inhibition of TNF-α/RIP1/RIP3/MLKL signaling pathway [17]. Effects evidenced in a dose-dependent manner. Furthermore, resveratrol treatment resulted in a significant reduction of inflammatory mediators in serum and cardiac tissue cells [18].
The beneficial effects of resveratrol in I/R injury could also be mediated via up-regulation of Keap1/Nrf2 signaling pathway. Nrf2 up-regulates the expression of proteins involved in the antioxidant response. This is suggested due to the reversion of the beneficial effects of resveratrol when a knock down or inhibition of Nrf2 is ensued [19].
A recent study suggested that resveratrol via activation of PI3K/AKT signaling pathway, reduced mitochondrial oxidative stress damage, increasing catalase, and glutathione peroxidase activity, and cell viability [15].
Resveratrol interferes with many of the mechanisms underlying myocardial I/R injury, but there are others that are not covered by it. In this context, it is reasonable to propose an association of resveratrol with other antioxidant compounds that have their effects on other targets. As an example, vitamin C down-regulates NOX activity and prevent eNOS uncoupling, which could synergize with the increased expression of antioxidant enzymes induced by resveratrol via Nrf2 signaling pathway activation.[7].
Quercetin is a flavonoid with anti-aggregating, anti-cancer, anti-inflammatory, anti-aging, and antioxidant properties. It is not toxic even in high doses, and recent studies have shown it to have tremendous potential to reduce myocardial damage that occurs after I/R. Although Que has a low bioavailability, many efforts are being made to increase its solubility [20][21].
Quercetin treatment has demonstrated to reduce oxidative stress through several mechanism. It reduces xanthine oxidase expression and activity [22] [23], and attenuate the expression of NOX2, which is one of the more active isoforms of NOX during I/R injury. Also, quercetin can significantly inhibit Fenton reaction, another relevant source of ROS [24]. Moreover, quercetin administration increased the selenoprotein TrxR2, which acts as an antioxidant and an indirect redox activity modulator [25] [26].
Acute inflammatory reactions are intensified in cardiomyocytes following I/R injury. This is due to the neutrophilic granulocytes, which are the ones that explain most of the reduced exudation and even the diffusion of these neutrophils through the blood vessels. Inflammation alter the function of endotheliocytes, reduce the relaxation capacities of coronary arteries, and promote coagulation [27]. Quercetin has been shown to improve inflammation and apoptosis of the myocardial tissue, resulting in a decrease of the final infarct size [28].
Not many associations have been tested, one of them is quercetin and α-tocopherol in rats. The combined pretreatment normalized all biochemical parameters and minimized ECG alterations, exhibiting enhanced cardioprotective effects against isoproterenol-induced cardiotoxicity. Furthermore, the combined pretreatment was more effective than each of them separately [29]. The combination of quercetin and lycopene in an animal model also prevented myocardial damage induced by isoproterenol, reducing oxidative stress [30].
Ischemia/reperfusion injury occurring in AMI patients undergoing PCI is a complex process involving pathophysiological cascades leading to cellular disturbances ranging from metabolic changes to cell death. The administration of several antioxidant molecules could give rise to an additive or synergistic pharmacological effect, leading to an improvement of previous studies on antioxidants that use them on monotherapy. tudies about associations of these compounds with others that have previously shown cardioprotective effects could be analyzed in isolated heart rat Langendorff model and, subsequently, in clinical trials aimed to reduce the infarct size due to the increased efficacy of this therapeutic association. This could lead to a better prognosis and quality of life after an acute myocardial infarction, decreasing complications, such as heart failure and arrhythmias, and reducing the associated costs.
Even if effective clinical treatment for I/R injury has not been found yet, resveratrol and quercetin constitute attractive natural pharmacological agents to be used in a combined therapy aimed to reduce cardiac tissue damage and infarct size due to their cardioprotective effects. Randomized double-blind clinical trials should be made to test the therapeutic efficacy as well as safety of these associations.