TNF-α antagonism ameliorates myocardial ischemia-reperfusion injury in mice by upregulating adiponectin

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

Macrophage-mediated heart repair and remodeling: A promising therapeutic target for post-myocardial infarction heart failure

Heart failure (HF) remains prevalent in patients who survived myocardial infarction (MI). Despite the accessibility of the primary percutaneous coronary intervention and medications that alleviate ventricular remodeling with functional improvement, there is an urgent need for clinicians and basic scientists to further reveal the mechanisms behind post-MI HF as well as investigate earlier and more efficient treatment after MI. Growing numbers of studies have highlighted the crucial role of macrophages in cardiac repair and remodeling following MI, and timely intervention targeting the immune response via macrophages may represent a promising therapeutic avenue. Recently, technology such as single-cell sequencing has provided us with an updated and in-depth understanding of the role of macrophages in MI. Meanwhile, the development of biomaterials has made it possible for macrophage-targeted therapy. Thus, an overall and thorough understanding of the role of macrophages in post-MI HF and the current development status of macrophage-based therapy will assist in the further study and development of macrophage-targeted treatment for post-infarction cardiac remodeling. This review synthesizes the spatiotemporal dynamics, function, mechanism and signaling of macrophages in the process of HF after MI, as well as discusses the emerging bio-materials and possible therapeutic agents targeting macrophages for post-MI HF.

IL6/adiponectin/HMGB1 feedback loop mediates adipocyte and macrophage crosstalk and M2 polarization after myocardial infarction

Background

Differences in border zone contribute to different outcomes post-infarction, such as left ventricular aneurysm (LVA) and myocardial infarction (MI). LVA usually forms within 24 h of the onset of MI and may cause heart rupture; however, LVA surgery is best performed 3 months after MI. Few studies have investigated the LVA model, the differences in border zones between LVA and MI, and the mechanism in the border zone.

Methods

The LVA, MI, and SHAM mouse models were used. Echocardiography, Masson's trichrome staining, and immunofluorescence staining were performed, and RNA sequencing of the border zone was conducted. The adipocyte-conditioned medium-treated hypoxic macrophage cell line and LVA and MI mouse models were employed to determine the effects of the hub gene, adiponectin (ADPN), on macrophages. Quantitative polymerase chain reaction (qPCR), Western blot analysis, transmission electron microscopy, and chromatin immunoprecipitation (ChIP) assays were conducted to elucidate the mechanism in the border zone. Human subepicardial adipose tissue and blood samples were collected to validate the effects of ADPN.

Results

A novel, simple, consistent, and low-cost LVA mouse model was constructed. LVA caused a greater reduction in contractile functions than MI owing to reduced wall thickness and edema in the border zone. ADPN impeded cardiac edema and promoted lymphangiogenesis by increasing macrophage infiltration post-infarction. Adipocyte-derived ADPN promoted M2 polarization and sustained mitochondrial quality via the ADPN/AdipoR2/HMGB1 axis. Mechanistically, ADPN impeded macrophage HMGB1 inflammation and decreased interleukin-6 (IL6) and HMGB1 secretion. The secretion of IL6 and HMGB1 increased ADPN expression via STAT3 and the co-transcription factor, YAP, in adipocytes. Based on ChIP and Dual-Glo luciferase experiments, STAT3 promoted ADPN transcription by binding to its promoter in adipocytes. In vivo, ADPN promoted lymphangiogenesis and decreased myocardial injury after MI. These phenotypes were rescued by macrophage depletion or HMGB1 knockdown in macrophages. Supplying adipocytes overexpressing STAT3 decreased collagen disposition, increased lymphangiogenesis, and impaired myocardial injury. However, these effects were rescued after HMGB1 knockdown in macrophages. Overall, the IL6/ADPN/HMGB1 axis was validated using human subepicardial tissue and blood samples. This axis could serve as an independent factor in overweight MI patients who need coronary artery bypass grafting (CABG) treatment.

Conclusion

The IL6/ADPN/HMGB1 loop between adipocytes and macrophages in the border zone contributes to different clinical outcomes post-infarction. Thus, targeting the IL6/ADPN/HMGB1 loop may be a novel therapeutic approach for cardiac lymphatic regulation and reduction of cell senescence post-infarction.

Changes of Serum Adiponectin Level in Patients with Obstructive Sleep Apnea Hypopnea Syndrome and Its Relationship with Sleep Monitoring Indexes

Objective

To observe the changes of serum adiponectin (AP) levels in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and explore the correlation between serum AP and polysomnography (PSG) parameters in patients with OSAHS.

Methods

The data of subjects who underwent PSG at the hospital between January 2021 and December 2022 were collected retrospectively and divided into simple snoring group (AHI < 5 times/h, n = 45), mild OSAHS group (5 ≤ AHI < 15 times/h, n = 63), moderate OSAHS group (15 ≤ AHI ≤ 30 times/h, n = 52), and severe OSAHS group (AHI > 30 times/h, n = 60). The general data, PSG indices, and serological indices of the subjects were collected and compared between groups. Pearson correlation analysis and partial correlation analysis were employed to examine the correlation between serum AP level and PSG parameters. Ordered logistic regression was employed to analyze the risk factors influencing the severity of OSAHS. The predictive capability of the serum AP level in determining the occurrence of OSAHS was assessed using ROC. The serum AP levels of subjects with different subtypes of PSG indicators were compared.

Results

In the simple snoring group, mild OSAHS group, moderate OSAHS group, and severe OSAHS group, there were statistically significant differences in microarousal count, MAI, AHI, times of blood oxygen decreased by ≥ 3%, L-SaO2, and TS90% among the 4 groups (P < 0.05). The level of serum AP was positively correlated with L-SaO2 and negatively correlated with the proportion of REM, microarousal count, MAI, AHI, times of blood oxygen decreased by ≥ 3%, TS90%, and LP (P < 0.05). High AHI was a risk factor affecting the severity of OSAHS (95% CI: 1.446-4.170). The AUC of serum AP level in diagnosing OSAHS was 0.906 (95% CI: 0.8601-0.9521), and when the Youden Index was 0.678, the sensitivity was 88.9%, and the specificity was 78.9% (P < 0.0001). In the population with a high microarousal count, high AHI, and high times of blood oxygen decreased by ≥ 3% and high TS90%, the serum AP level was lower than that in the low-level population (P < 0.05). In the population with high L-SaO2, the serum AP level was higher than that in low-level population (P < 0.05).

Conclusion

The level of serum AP decreased with the increase of the disease severity of patients with OSAHS and demonstrates a significant predictive capability for the occurrence of OSAHS. Monitoring the level of serum AP can effectively forecast the risk of OSAHS. Furthermore, alterations in serum AP levels are associated with both hypoxemia and a heightened frequency of arousal in patients with OSAHS.

Adiponectin protects against myocardial ischemia-reperfusion injury: a systematic review and meta-analysis of preclinical animal studies

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) is widespread in the treatment of ischemic heart disease, and its treatment options are currently limited. Adiponectin (APN) is an adipocytokine with cardioprotective properties; however, the mechanisms of APN in MIRI are unclear. Therefore, based on preclinical (animal model) evidence, the cardioprotective effects of APN and the underlying mechanisms were explored.

METHODS

The literature was searched for the protective effect of APN on MIRI in six databases until 16 November 2023, and data were extracted according to selection criteria. The outcomes were the size of the myocardial necrosis area and hemodynamics. Markers of oxidation, apoptosis, and inflammation were secondary outcome indicators. The quality evaluation was performed using the animal study evaluation scale recommended by the Systematic Review Center for Laboratory animal Experimentation statement. Stata/MP 14.0 software was used for the summary analysis.

RESULTS

In total, 20 papers with 426 animals were included in this study. The pooled analysis revealed that APN significantly reduced myocardial infarct size [weighted mean difference (WMD) = 16.67 (95% confidence interval (CI) = 13.18 to 20.16, P < 0.001)] and improved hemodynamics compared to the MIRI group [Left ventricular end-diastolic pressure: WMD = 5.96 (95% CI = 4.23 to 7.70, P < 0.001); + dP/dtmax: WMD = 1393.59 (95% CI = 972.57 to 1814.60, P < 0.001); -dP/dtmax: WMD = 850.06 (95% CI = 541.22 to 1158.90, P < 0.001); Left ventricular ejection fraction: WMD = 9.96 (95% CI = 7.29 to 12.63, P < 0.001)]. Apoptosis indicators [caspase-3: standardized mean difference (SMD) = 3.86 (95% CI = 2.97 to 4.76, P < 0.001); TUNEL-positive cells: WMD = 13.10 (95% CI = 8.15 to 18.05, P < 0.001)], inflammatory factor levels [TNF-α: SMD = 4.23 (95% CI = 2.48 to 5.98, P < 0.001)], oxidative stress indicators [Superoxide production: SMD = 4.53 (95% CI = 2.39 to 6.67, P < 0.001)], and lactate dehydrogenase levels [SMD = 2.82 (95% CI = 1.60 to 4.04, P < 0.001)] were significantly reduced. However, the superoxide dismutase content was significantly increased [SMD = 1.91 (95% CI = 1.17 to 2.65, P < 0.001)].

CONCLUSION

APN protects against MIRI via anti-inflammatory, antiapoptotic, and antioxidant effects, and this effect is achieved by activating different signaling pathways.

Non-coding RNAs modulate pyroptosis in myocardial ischemia-reperfusion injury: A comprehensive review

Reperfusion therapy is the most effective treatment for acute myocardial infarction. However, reperfusion itself can also cause cardiomyocytes damage. Pyroptosis has been shown to be an important mode of myocardial cell death during ischemia-reperfusion. Non-coding RNAs (ncRNAs) play critical roles in regulating pyroptosis. The regulation of pyroptosis by microRNAs, long ncRNAs, and circular RNAs may represent a new mechanism of myocardial ischemia-reperfusion injury. This review summarizes the currently known regulatory roles of ncRNAs in myocardial ischemia-reperfusion injury and interactions between ncRNAs. Potential therapeutic strategies using ncRNA modulation are also discussed.

Local injection of bone-marrow derived mesenchymal stromal cells alters a molecular expression profile of a contact frostbite injury wound and improves healing in a rat model

INTRODUCTION

Frostbite is a traumatic injury of the tissues upon low temperature environment exposure, which is characterized by direct cell injury due to freezing-thawing followed by development of an acute inflammatory process. Severe frostbite can lead to necrosis of soft tissues and loss of a limb. Mesenchymal stromal cells (MSCs) have a unique ability to modulate pathogenic immune response by secretion of paracrine factors, which suppress inflammation and mediate more efficient tissue regeneration. It should be noted that potential of stem cell therapy for frostbite injury treatment has not been investigated so far. Here, we evaluated a healing capacity of bone-marrow derived MSCs for the treatment of contact frostbite injury wound in a rat model.

METHODS

Cold-contact injury in a Wistar rat model was induced by 1-minute tight application of the cooled probe (-196 ⁰C) to the skin surface of the left hip. Rat bone marrow MSCs were phenotypically characterized and used for local injections into non-damaged tissues surrounding the wound of animals from the experimental group. The second group of rats was treated in the same manner with 1 mL of isotonic sodium chloride solution. Analysis of cytokine and growth factor expression profile in сold-contact injury wounds was performed on days 5, 9, and 16 using immunoblotting and enzyme-linked immunosorbent assay. Animal recovery in MSC-treated and vehicle-treated groups was evaluated by several criteria including body weight recording, determination of eschar desquamation and re-epithelialization terms, assessment of wound closure kinetics, and histological scoring of the wounds on day 23.

RESULTS

It turned out that a single subcutaneous administration of MSCs around the wound site resulted in elevated expression of pro-survival and pro-angiogenic VEGF-A and PDGF and 3-5-fold decrease in pro-inflammatory IL-1β as compared with the frostbite wound treated with a vehicle. Moreover, treatment with MSCs caused accelerated wound re-epithelialization (p < 0.05) as well as a better histological score of the MSC-treated wounds.

CONCLUSIONS

Thus, our data suggested that the use of MSCs is a promising therapeutic strategy for the treatment of cold-induced injury wounds.

Hydrogel delivery of purinergic enzymes improves cardiac ischemia/reperfusion injury

RATIONALE

The innate immune response contributes to cardiac injury in myocardial ischemia/reperfusion (MI/R). Neutrophils are an important early part of the innate immune response to MI/R. Adenosine, an endogenous purine, is a known innate immune modulator and inhibitor of neutrophil activation. However, its delivery to the heart is limited by its short half-life (<30 s) and off-target side effects. CD39 and CD73 are anti-inflammatory homeostatic enzymes that can generate adenosine from phosphorylated adenosine substrate such as ATP released from injured tissue.

OBJECTIVE

We hypothesize that hydrogel-delivered CD39 and CD73 target the local early innate immune response, reduce neutrophil activation, and preserve cardiac function in MI/R injury.

METHODS AND RESULTS

We engineered a poly(ethylene) glycol (PEG) hydrogel loaded with the adenosine-generating enzymes CD39 and CD73. We incubated the hydrogels with neutrophils in vitro and showed a reduction in hydrogen peroxide production using Amplex Red. We demonstrated availability of substrate for the enzymes in the myocardium in MI/R by LC/MS, and tested release kinetics from the hydrogel. On echocardiography, global longitudinal strain (GLS) was preserved in MI/R hearts treated with the loaded hydrogel. Delivery of purinergic enzymes via this synthetic hydrogel resulted in lower innate immune infiltration into the myocardium post-MI/R, decreased markers of macrophage and neutrophil activation (NETosis), and decreased leukocyte-platelet complexes in circulation.

CONCLUSIONS

In a rat model of MI/R injury, CD39 and CD73 delivered via a hydrogel preserve cardiac function by modulating the innate immune response.

Tumor Necrosis Factor Family Members and Myocardial Ischemia-Reperfusion Injury: State of the Art and Therapeutic Implications

Ischemic heart disease is the principal cause of death worldwide and clinically manifests as myocardial infarction (MI), stable angina, and ischemic cardiomyopathy. Myocardial infarction is defined as an irreversible injury due to severe and prolonged myocardial ischemia inducing myocardial cell death. Revascularization is helpful in reducing loss of contractile myocardium and improving clinical outcome. Reperfusion rescues myocardium from cell death but also induces an additional injury called ischemia-reperfusion injury. Multiple mechanisms are involved in ischemia-reperfusion injury, such as oxidative stress, intracellular calcium overload, apoptosis, necroptosis, pyroptosis, and inflammation. Various members of the tumor necrosis factor family play a key role in myocardial ischemia-reperfusion injury. In this article, the role of TNFα, CD95L/CD95, TRAIL, and the RANK/RANKL/OPG axis in the regulation of myocardial tissue damage is reviewed together with their potential use as a therapeutic target.

KMT2B-dependent RFK transcription activates the TNF-α/NOX2 pathway and enhances ferroptosis caused by myocardial ischemia-reperfusion

Epigenetic regulation such as histone modification is implicated in the pathogenesis of myocardial ischemia/reperfusion injury (MIRI). Lysine-specific methyltransferase 2B (KMT2B) is a histone H3 lysine 4 (H3K4) methyltransferase. This study aims at exploring the role of KMT2B-mediated histone modification in MIRI. Peripheral blood samples were collected from 30 patients with acute myocardial infarction (AMI) and 30 healthy volunteers for analyses of the expression levels of KMT2B, riboflavin kinase (RFK), tumor necrosis factor (TNF)-α, and NADPH oxidase 2 (NOX2). H9C2 cardiomyocytes and Sprague-Dawley rats were utilized for developing in vitro and in vivo models. To evaluate the effects of the aforementioned molecules on cellular damage and MIRI, short hairpin RNAs or overexpression plasmids were introduced into cardiomyocytes for gene silencing or overexpression and also, they were packaged into adenovirus vectors for in vivo interventions. Immunoprecipitation assays were conducted to assess the interactions between KMT2B and RFK and among RFK, NOX2 sub-unit p22phox, and TNF receptor 1-associated death domain protein. KMT2B, RFK, TNF-α, and NOX2 were notably upregulated in AMI patients. KMT2B knockdown resulted in considerably attenuated cell apoptosis and reduced myocardial infarct area. Additionally, the release of pro-inflammatory proteins and ferroptosis were suppressed. Furthermore, KMT2B could promote RFK gene transcription by upregulating H3 methylation levels and consequently activate the TNF-α/NOX2 axis, which was the possible mechanism underlying the role of KMT2B in MIRI. KMT2B motivates MIRI-induced cellular injury and ferroptosis by inducing RFK transcription and mediating the TNF-α/NOX2 axis.

Myocardial Protection and Current Cancer Therapy: Two Opposite Targets with Inevitable Cost

Myocardial protection against ischemia/reperfusion injury (IRI) is mediated by various ligands, activating different cellular signaling cascades. These include classical cytosolic mediators such as cyclic-GMP (c-GMP), various kinases such as Phosphatydilinositol-3- (PI3K), Protein Kinase B (Akt), Mitogen-Activated-Protein- (MAPK) and AMP-activated (AMPK) kinases, transcription factors such as signal transducer and activator of transcription 3 (STAT3) and bioactive molecules such as vascular endothelial growth factor (VEGF). Most of the aforementioned signaling molecules constitute targets of anticancer therapy; as they are also involved in carcinogenesis, most of the current anti-neoplastic drugs lead to concomitant weakening or even complete abrogation of myocardial cell tolerance to ischemic or oxidative stress. Furthermore, many anti-neoplastic drugs may directly induce cardiotoxicity via their pharmacological effects, or indirectly via their cardiovascular side effects. The combination of direct drug cardiotoxicity, indirect cardiovascular side effects and neutralization of the cardioprotective defense mechanisms of the heart by prolonged cancer treatment may induce long-term ventricular dysfunction, or even clinically manifested heart failure. We present a narrative review of three therapeutic interventions, namely VEGF, proteasome and Immune Checkpoint inhibitors, having opposing effects on the same intracellular signal cascades thereby affecting the heart. Moreover, we herein comment on the current guidelines for managing cardiotoxicity in the clinical setting and on the role of cardiovascular confounders in cardiotoxicity.

Kukoamine A activates Akt/GSK-3β signaling pathway to inhibit oxidative stress and relieve myocardial ischemia-reperfusion injury

Purpose:

Myocardial ischemia/reperfusion (MI/R) injury refers to a pathological condition of treatment of myocardial infarction. Oxidative stress and inflammation are believed to be important mechanisms mediating MI/R injury. Kukoamine A (KuA), a sperm, is the main bioactive component extracted from the bark of goji berries. In this study, we wanted to investigate the possible effects of KuA on MI/R injury.

Methods:

In this experiment, all rats were divided into sham operation group, MI/R group, KuA 10 mg + MI/R group, KuA 20 mg + MI/R group. After 120 min of ischemia/reperfusion treatment, left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximal rates of rising and fall of left ventricular pressure (±dp/dtmax), and ischemic area were detected. Serum samples of rats in each group were collected. The enzyme activities of catalase (CAT), glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), levels of malondialdehyde (MDA), CK muscle/brain (CK-MB), tumor necrosis factor (TNF), interleukin-1β (IL-1β), and interleukin-6 (IL-6) were detected using enzyme-linked immunosorbent assay (ELISA). The apoptosis of myocardium in each group was detected according to the instructions of the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The expressions of mammalian target of glycogen synthase kinase-3β (GSH-3β) and protein kinase B (Akt) mRNA level in myocardial tissues were detected via reverse transcription-polymerase chain reaction (RT-PCR).

Results:

MI/R rats showed a significant increase in oxidative stress and inflammation. In addition, we showed that KuA significantly improved the myocardial function such as LVSP, left ventricular ejection fraction, +dp/dt, and -dp/dt. Here, it attenuated dose-dependent histological damage in ischemia-reperfused myocardium, which is associated with the enzyme activities of SOD, GSH-PX, and levels of MDA, IL-6, TNF-α, L-1β.

Conclusions:

KuA inhibited gene expression of Akt/GSK-3β, inflammation, oxidative stress and improved MR/I injury. Taken together, our results allowed us to better understand the pharmacological activity of KuA against MR/I injury.

Aib1 deficiency exacerbates inflammatory responses in acute myocardial infarction mice

Acute myocardial infarction (AMI) is one of the major causes of death throughout the world, while inflammation has been known as a major contributor to the pathophysiology of AMI. Inhibition of inflammation is shown to protect from AMI. Amplified in breast 1 (Aib1) is a transcriptional coactivator protein which can suppress inflammation. The anti-inflammatory activities of Aib1 imply its potential effects against AMI; however, to date the role of Aib1 in AMI has not been described yet. Here we explored the potential functions of Aib1 in AMI. We induced AMI in both wild-type (WT) and Aib1^-/- mice. The expression levels of Aib1 and inflammatory cytokines in the AMI WT mice were measured by RT-PCR and Western blot. The heart infarction area and cardiac functions were compared between the AMI WT and Aib1^-/- mice. The expression levels of inflammatory cytokines including IL-6, IL-1β, TNF-α, and MCP-1 in heart tissues were compared between the AMI WT and Aib1^-/- mice by ELISA and RT-PCR. AMI induced the production of inflammatory cytokines whereas suppressed the expression of Aib1 in WT mice. AMI Aib1^-/- mice displayed increased infarct area and aggravated heart dysfunction, as well as upregulated levels of Il-6, Il-1β, Tnf-α, and Mcp-1 in heart tissues. Aib1 deficiency exacerbates inflammation in AMI mice. KEY MESSAGES: AMI induced inflammation in the heart tissue of mice. Aib1 knockout exacerbated infarction in AMI mice. Aib1 knockout exacerbated cardiac dysfunction in AMI mice. Aib1 knockout exacerbated inflammation in AMI mice.

Geniposide suppresses NLRP3 inflammasome-mediated pyroptosis via the AMPK signaling pathway to mitigate myocardial ischemia/reperfusion injury

BACKGROUND

NLRP3 inflammasome activation and pyroptosis play a significant role in myocardial ischemia reperfusion injury (MI/RI). Geniposide was reported to show potential therapeutic use for MI/RI with its anti-inflammatory and anti-oxidative properties. However, research on the specific mechanism of geniposide has not been reported.

METHODS

The MIRI model of animal was created in male C57BL/6J mice and the hypoxia reoxygenation (H/R) model was established for the in vitro experiments. Neonatal rat ventricular myocytes (NRVMs) and H9c2 cells with knockdown of TXNIP or NLRP3 were used. Geniposide was administered to mice before vascular ligation. HE staining, 2,3,5-triphenyltetrazolium chloride (TTC) staining, echocardiography, oxidative stress and myocardial enzyme detection were used to evaluate the cardioprotective effect of geniposide. Meanwhile, pharmacological approaches of agonist and inhibitor were used to observe potential pathway for geniposide cardioprotective in vitro and in vivo. Moreover, ELISA kits were adopted to detect the levels of inflammatory factors, such as IL-1β and IL-18. The gene and protein expression of NLRP3 and pyroptosis-related factors in heart tissue were performed by RT-PCR, western blotting and immunofluorescence in vivo and in vitro, respectively.

RESULTS

Our results indicate that geniposide can reduce the area of myocardial infarction, improve heart function, and inhibit the inflammatory response in mice after MI/RI. In addition, RT-PCR and western blotting shown geniposide promoting AMPK phosphorylation to activate myocardium energy metabolism and reducing the levels of genes and proteins expression of NLRP3, ASC, N-GSDMD and cleaved caspase-1, IL-1β, IL-18. Meanwhile, geniposide improved NRVMs energy metabolism, which decreased ROS levels and the protein expression of TXNIP and thus suppressed the expression of NLRP3. AMPK antagonist or agonist and siRNA downregulation of TXNIP or NLRP3 were also verify the effect of geniposide against H/R injury. Further research found that geniposide promoted the translocation of TXNIP and reduce the binding of TXNIP and NLRP3.

CONCLUSIONS

In our study, geniposide can significantly inhibit NLRP3 inflammasome activation via the AMPK signaling pathway and inhibit pyroptosis of cardiomyocytes in myocardial tissues.

The effect of adaptation to hypoxia on cardiac tolerance to ischemia/reperfusion

The acute myocardial infarction (AMI) and sudden cardiac death (SCD), both associated with acute cardiac ischemia, are one of the leading causes of adult death in economically developed countries. The development of new approaches for the treatment and prevention of AMI and SCD remains the highest priority for medicine. A study on the cardiovascular effects of chronic hypoxia (CH) may contribute to the development of these methods. Chronic hypoxia exerts both positive and adverse effects. The positive effects are the infarct-reducing, vasoprotective, and antiarrhythmic effects, which can lead to the improvement of cardiac contractility in reperfusion. The adverse effects are pulmonary hypertension and right ventricular hypertrophy. This review presents a comprehensive overview of how CH enhances cardiac tolerance to ischemia/reperfusion. It is an in-depth analysis of the published data on the underlying mechanisms, which can lead to future development of the cardioprotective effect of CH. A better understanding of the CH-activated protective signaling pathways may contribute to new therapeutic approaches in an increase of cardiac tolerance to ischemia/reperfusion.

LncRNA PVT1 Knockdown Ameliorates Myocardial Ischemia Reperfusion Damage via Suppressing Gasdermin D-Mediated Pyroptosis in Cardiomyocytes

Objective: Myocardial ischemia reperfusion (I/R) damage is a life-threatening vascular emergency after myocardial infarction. Here, we observed the cardioprotective effect of long non-coding RNA (lncRNA) PVT1 knockdown against myocardial I/R damage.

Methods: This study constructed a myocardial I/R-induced mouse model and a hypoxia/reoxygenation (H/R)-treated H9C2 cells. PVT1 expression was examined via RT-qPCR. After silencing PVT1 via shRNA against PVT1, H&E, and Masson staining was performed to observe myocardial I/R damage. Indicators of myocardial injury including cTnI, LDH, BNP, and CK-MB were examined by ELISA. Inflammatory factors (TNF-α, IL-1β, and IL-6), Gasdermin D (GSDMD), and Caspase1 were detected via RT-qPCR, western blot, immunohistochemistry, or immunofluorescence. Furthermore, CCK-8 and flow cytometry were presented for detecting cell viability and apoptosis.

Results: LncRNA PVT1 was markedly up-regulated in myocardial I/R tissue specimens as well as H/R-induced H9C2 cells. Silencing PVT1 significantly lowered serum levels of cTnI, LDH, BNP, and CK-MB in myocardial I/R mice. H&E and Masson staining showed that silencing PVT1 alleviated myocardial I/R injury. PVT1 knockdown significantly lowered the production and release of inflammatory factors as well as inhibited the expression of GSDMD-N and Caspase1 in myocardial I/R tissue specimens as well as H/R-induced H9C2 cells. Moreover, silencing PVT1 facilitated cell viability and induced apoptosis of H/R-treated H9C2 cells.

Conclusion: Our findings demonstrated that silencing PVT1 could alleviate myocardial I/R damage through suppressing GSDMD-mediated pyroptosis in vivo and in vitro. Thus, PVT1 knockdown may offer an alternative therapeutic strategy against myocardial I/R damage.

Adiponectin and cardiometabolic trait and mortality: where do we go?

Adiponectin is an adipocyte-derived cytokine known for its cardioprotective effects in preclinical studies. Early epidemiologic studies replicated these findings and drew great interest. Subsequent large-scale prospective cohorts, however, showed that adiponectin levels seemed not to relate to incident coronary artery disease (CAD). Even more surprisingly, a paradoxical increase of all-cause and cardiovascular (CV) mortality with increased adiponectin levels was reported. The adiponectin-mortality paradox has been explained by some groups asserting that adiponectin secretion is promoted by elevated natriuretic peptides (NP). Other groups have proposed that adiponectin is elevated due to adiponectin resistance in subjects with metabolic syndrome or heart failure (HF). However, there is no unifying theory that can clearly explain this paradox. In patients with HF with reduced ejection fraction (HFrEF), stretched cardiomyocytes secrete NPs, which further promote release of adiponectin from adipose tissue, leading to adiponectin resistance. On the other hand, adiponectin biology may differ in patients with heart failure with preserved ejection fraction (HFpEF), which constitutes 50% of all of HF. Most HFpEF patients are obese, which exerts inflammation and myocardial stiffness, that is likely to prevent myocardial stretch and subsequent NP release. This segment of the patient population may display a different adiponectin biology from its HFrEF counterpart. Dissecting the adiponectin-mortality relation in terms of different HF subtypes may help to comprehensively understand this paradox. Mendelian Randomization (MR) analyses claimed that adiponectin levels are not causally related to CAD or metabolic syndrome. Results from MR studies, however, should be interpreted with great caution because the underlying history of CAD or CHF were not taken into account in these analyses, an issue that may substantially confound the results. Here, we discuss many aspects of adiponectin; cardiometabolic traits, therapeutic interventions, and the ongoing debate about the adiponectin paradox, which were recently described in basic, epidemiologic, and clinical studies.

Attenuating ischemia/reperfusion injury in rat cardiac transplantation by intracoronary infusion with siRNA cocktail solution

Tumor necrosis factor-α (TNF-α), caspase-8, and complement component 5a receptor (C5aR) are known to play a crucial role in the myocardial ischemia/reperfusion (I/R) injury in cardiac transplantation. We hypothesized that the intracoronary infusion of TNF-α, caspase-8, and C5aR small interfering RNAs (siRNA) would protect cardiac allograft function and improve graft survival from I/R injury-induced organ failure. I/R injury of cardiac allograft was induced by syngeneic rat cardiac transplantation, in which the transplanted hearts were infused with saline or different amounts of siRNA cocktail solution targeting TNF-α, caspase-8, and C5aR via coronary arteries, and subsequently subjected to 18 h of preservation at 4°C in histidine–tryptophan–ketoglutarate (HTK) solution. The effects of siRNA cocktail solution on prolonged cold I/R injury were determined by assessing graft survival, histopathological changes, myeloperoxidase (MPO) activity, and malondialdehyde (MDA) concentration. The perfused siRNA cocktail solution successfully knocked down the expression of TNF-α, caspase-8, and C5aR in vitro and in vivo. Approximately 91.7% of control hearts that underwent 18 h of cold ischemia ceased their function after transplantation; however, 87.5% of cardiac allografts from the highest dose siRNA cocktail solution-pretreated hearts survived >14 days and exhibited minimal histological changes, with minimal cellular infiltration, interstitial edema, and inflammation and maximal reduced MPO activity and MDA concentration in the cardiac allograft. We demonstrated the feasibility and efficiency of infusion of TNF-α, caspase-8, and C5aR siRNA via the intracoronary route as a promising strategy for gene silencing against I/R injury in cardiac transplantation.

Cytokines as therapeutic targets for cardio- and cerebrovascular diseases

Despite major advances in prevention and treatment, cardiac and cerebral atherothrombotic complications still account for substantial morbidity and mortality worldwide. In this context, inflammation is involved in the chronic process leading atherosclerotic plaque formation and its complications, as well as in the maladaptive response to acute ischemic events. For this reason, modulation of inflammation is nowadays seen as a promising therapeutic strategy to counteract the burden of cardio- and cerebrovascular disease. Being produced and recognized by both inflammatory and vascular cells, the complex network of cytokines holds key functions in the crosstalk of these two systems and orchestrates the progression of atherothrombosis. By binding to membrane receptors, these soluble mediators trigger specific intracellular signaling pathways eventually leading to the activation of transcription factors and a deep modulation of cell function. Both stimulatory and inhibitory cytokines have been described and progressively reported as markers of disease or interesting therapeutic targets in the cardiovascular field. Nevertheless, cytokine inhibition is burdened by harmful side effects that will most likely prevent its chronic use in favor of acute administrations in well-selected subjects at high risk. Here, we summarize the current state of knowledge regarding the modulatory role of cytokines on atherosclerosis, myocardial infarction, and stroke. Then, we discuss evidence from clinical trials specifically targeting cytokines and the potential implication of these advances into daily clinical practice.

Resveratrol inhibits necroptosis by mediating the TNF-α/RIP1/RIP3/MLKL pathway in myocardial hypoxia/reoxygenation injury

Resveratrol (RES) protects myocardial cells from hypoxia/reoxygenation (H/R)-caused injury. However, the mechanism of this effect has not been clarified. Thus, in this study, we aimed to determine whether RES attenuates H/R-induced cell necroptosis by inhibiting the tumor necrosis factor-alpha (TNF-α)/receptor-interacting protein kinase 1 (RIP1)/RIP3/mixed-lineage kinase domain-like (MLKL) signaling pathway. Rat myocardial ischemia/reperfusion (I/R) models and H/R-injured cell models were constructed. Our study showed that myocardial H/R injury significantly increased the levels of TNF-α, RIP1, RIP3, and p-MLKL/MLKL by western blot analysis. Cell viability assay and 4,6-dianmidino-2-phenylindole (DAPI)-propidium iodide staining showed that the cell viability was decreased, and necroptosis was increased after myocardial H/R injury. The expressions of TNF-α, RIP1, RIP3, and p-MLKL/MLKL in H/R myocardial cells treated with different concentrations of RES were significantly downregulated. In addition, we also found that the cell viability was increased and necroptosis was decreased in dose-dependent manners when H/R-injured cells were treated with RES. In addition, the enhanced effect of TNF-α on necroptosis in myocardial H/R-injured cells was improved by RES, and the effect of RES was confirmed in vivo in I/R rats. This study also showed that RES suppresses necroptosis in H9c2 cells, which may occur through the inhibition of the TNF-α/RIP1/RIP3/MLKL signaling pathway. Our data suggest that necroptosis is a promising therapeutic target and may be a promising therapeutic target for the treatment of myocardial I/R injury.

Network pharmacology exploration reveals a common mechanism in the treatment of cardio-cerebrovascular disease with Salvia miltiorrhiza Burge. and Carthamus tinctorius L

BACKGROUND

This study aimed to identify the key genes and KEGG pathways in Carthamus tinctorius L. (Safflower) and Salvia miltiorrhiza Burge. (Salvia) for the treatment of cardio-cerebrovascular disease, and to explore their potential molecular mechanisms.

METHODS

Compounds and targets in Safflower and Salvia were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). We obtained targets of myocardial infarction (MI) and cerebral infarction (CI) data from Therapeutic Target Database (TTD), Drugbank and DisGeNET datasets. The network of Safflower, Salvia, CI and MI was established and then executing, and Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses of the functional characteristics were performed. The Chinese herbal prescription and target for CI and MI were obtained by searching in the database. Finally, the main pathways of Salvia and Safflower in Chinese patent medicines were analyzed. The MCAO model was established in rats, and compatibility of salvia with safflower was experimentally verified.

RESULTS

We obtained a total of 247 genes targeted by 52 compounds from Safflower and 119 genes targeted by 48 compounds from Salvia. In total, we identified 299 known therapeutic targets for the treatment of CI and 960 targets for the treatment MI. There are 23 common targets for Salvia, Safflower, MI, and CI. A total of 85 KEGG pathways were also enriched and intersected with the pathway of proprietary Chinese medicine to yield 25 main pathways. Safflower and Salvia have the best therapeutic effect in MCAO.

CONCLUSION

We identified gene lists for Safflower and Salvia in CI and MI. Bioinformatics and interaction analyses may provide new insight into the treatment of cardio-cerebrovascular diseases with Safflower and Salvia.

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases.

Complexity of TNF-α Signaling in Heart Disease

Heart disease is a leading cause of death with unmet clinical needs for targeted treatment options. Tumor necrosis factor alpha (TNF-α) represents a master pro-inflammatory cytokine that plays an important role in many immunopathogenic processes. Anti-TNF-α therapy is widely used in treating autoimmune inflammatory disorders, but in case of patients with heart disease, this treatment was unsuccessful or even harmful. The underlying reasons remain elusive until today. This review summarizes the effects of anti-TNF-α treatment in patients with and without heart disease and describes the involvement of TNF-α signaling in a number of animal models of cardiovascular diseases. We specifically focused on the role of TNF-α in specific cardiovascular conditions and in defined cardiac cell types. Although some mechanisms, mainly in disease development, are quite well known, a comprehensive understanding of TNF-α signaling in the failing heart is still incomplete. Published data identify pathogenic and cardioprotective mechanisms of TNF-α in the affected heart and highlight the differential role of two TNF-α receptors pointing to the complexity of the TNF-α signaling. In the light of these findings, it seems that targeting the TNF-α pathway in heart disease may show therapeutic benefits, but this approach must be more specific and selectively block pathogenic mechanisms. To this aim, more research is needed to better understand the molecular mechanisms of TNF-α signaling in the failing heart.

The role of adiponectin in ischemia-reperfusion syndrome: a literature review

Adiponectin, among other diverse adipokines, is produced in greater quantity and has an effect on the adipose tissue and other tissues in the body. Adiponectin plays three main roles: regulatory metabolic and sensitizing function of insulin in the liver and muscles; it acts as an anti-inflammatory cytokine and in vascular protection, besides important cardiac protection in the presence of ischemia-reperfusion syndrome. Since many situations resulting from traumatic accidents or pathologies are due to cell damage caused by ischemia-reperfusion syndrome, it is relevant to study new therapeutic alternatives that will contribute to reducing these lesions. The objective of this study is to carry out a literature review on the role of adiponectin in ischemia-reperfusion syndrome.

Adeno-associated Virus 9-mediated Small RNA Interference of TLR4 Alleviates Myocardial Ischemia and Reperfusion Injury by Inhibition of the NF-κB and MAPK Signaling Pathways in Rats

BACKGROUND

Despite intensive investigation, effective therapeutic procedures for myocardial I/R injury are still in demand.

OBJECTIVE

To explore the effect of adeno-associated virus 9 (AAV9)-mediated small interfering RNA targeting TLR4 in the treatment of myocardial ischemia and reperfusion (I/R) injury and its influence on the NF-κB and MAPK signaling pathways.

METHODS

Rats were divided into 3 groups, namely, the sham, AAV9-siRNA control, and AAV9-TLR4 siRNA groups. siRNA solution or normal saline was injected through the tail vain. The rat myocardial I/R injury model was then established. HE staining and TUNEL staining were applied to compare the pathological changes in cardiomyocytes in the three groups. Immunohistochemical staining and western blotting were utilized to detect TLR4 expression under siRNA interference. Serum inflammatory factor (IL-1β, TNF-α) expression was determined by an ELISA commercial kit. Key proteins in the MAPK (p38, JNK 1/2) and NF-κB (p65) signaling pathways were determined to identify the TLR4 siRNA functional mechanism.

RESULTS

Fluorescence microscopic images of the myocardium indicated that AAV9- mediated siRNA was efficiently transfected into the myocardium, and the infarcted size after I/R injury was decreased by AAV9-TLR4 siRNA when compared with negative control rats (P<0.05). TLR4 protein expression was significantly decreased by siRNA interference (P<0.001). Apoptosis-related factor BCL-2 expression was increased in the TLR4 gene silencing group, whereas Bax expression was decreased. The Bax/BCL-2 ratio was also decreased, demonstrating a protective effect for cardiomyocytes. Inflammatory factors were lower in the TLR4 gene silencing group than in the siRNA control group (P<0.001). The MAPK and NF-κB signaling pathways were activated in myocardial I/R injury; however, the primary proteins in these two signaling pathways were downregulated upon interference of TLR4 siRNA, with significant differences (P<0.05).

CONCLUSION

AAV9-TLR4 siRNA has a positive effect on myocardial I/R injury by inhibiting the MAPK and NF-κB signaling pathways and can be used as a potential therapeutic method for myocardial I/R injury.

Ischemia/Reperfusion Injury Revisited: An Overview of the Latest Pharmacological Strategies

Ischemia/reperfusion injury (IRI) permeates a variety of diseases and is a ubiquitous concern in every transplantation proceeding, from whole organs to modest grafts. Given its significance, efforts to evade the damaging effects of both ischemia and reperfusion are abundant in the literature and they consist of several strategies, such as applying pre-ischemic conditioning protocols, improving protection from preservation solutions, thus providing extended cold ischemia time and so on. In this review, we describe many of the latest pharmacological approaches that have been proven effective against IRI, while also revisiting well-established concepts and presenting recent pathophysiological findings in this ever-expanding field. A plethora of promising protocols has emerged in the last few years. They have been showing exciting results regarding protection against IRI by employing drugs that engage several strategies, such as modulating cell-surviving pathways, evading oxidative damage, physically protecting cell membrane integrity, and enhancing cell energetics.

Toward Regeneration of the Heart: Bioengineering Strategies for Immunomodulation

Myocardial Infarction (MI) is the most common cardiovascular disease. An average-sized MI causes the loss of up to 1 billion cardiomyocytes and the adult heart lacks the capacity to replace them. Although post-MI treatment has dramatically improved survival rates over the last few decades, more than 20% of patients affected by MI will subsequently develop heart failure (HF), an incurable condition where the contracting myocardium is transformed into an akinetic, fibrotic scar, unable to meet the body's need for blood supply. Excessive inflammation and persistent immune auto-reactivity have been suggested to contribute to post-MI tissue damage and exacerbate HF development. Two newly emerging fields of biomedical research, immunomodulatory therapies and cardiac bioengineering, provide potential options to target the causative mechanisms underlying HF development. Combining these two fields to develop biomaterials for delivery of immunomodulatory bioactive molecules holds great promise for HF therapy. Specifically, minimally invasive delivery of injectable hydrogels, loaded with bioactive factors with angiogenic, proliferative, anti-apoptotic and immunomodulatory functions, is a promising route for influencing the cascade of immune events post-MI, preventing adverse left ventricular remodeling, and offering protection from early inflammation to fibrosis. Here we provide an updated overview on the main injectable hydrogel systems and bioactive factors that have been tested in animal models with promising results and discuss the challenges to be addressed for accelerating the development of these novel therapeutic strategies.

Potential Adiponectin Receptor Response Modifier Therapeutics

Many human diseases may benefit from adiponectin replacement therapy, but due to pharmacological disadvantages of the intact protein, druggable options focus on peptidic, and small molecule agonists of the adiponectin receptor. Peptide-based adiponectin replacement drug leads are derived from, or resemble, the active site of globular adiponectin. ADP355, the first-in-class such peptide, exhibits low nanomolar cellular activities, and clinically acceptable efficacies in a series of fibrotic and inflammation-derived diseases. The advantage of small molecule therapies, spearheaded by AdipoRon, is oral availability and extension of utility to a series of metabolic conditions. It is exactly the difficulties in the reliability and readout of the in vitro measures and the wealth of in vivo models that make comparison of the various drug classes complicated, if not impossible. While only a fewer number of maladies could take advantage of adiponectin receptor antagonists, the limited number of these available can be very useful tools in target validation studies. Alternative approaches to direct adiponectin signaling control use upstream adiponectin production inducing therapies but currently these offer relatively limited success compared to direct receptor agonists.

Tranexamic Acid Does Not Influence Cardioprotection by Ischemic Preconditioning and Remote Ischemic Preconditioning

Prior studies have suggested that the antifibrinolytic drug aprotinin increases the infarct size after ischemia and reperfusion (I/R) and attenuates the effect of ischemic preconditioning (IPC). Aprotinin was replaced by tranexamic acid (TXA) in clinical practice. Here, we investigated whether TXA influences I/R injury and/or cardioprotection initiated by IPC and/or remote ischemic preconditioning (RIPC). Anesthetized male Wistar rats were randomized to 6 groups. Control animals were not further treated. Administration of TXA was combined with and without IPC and RIPC. Estimated treatment effect was 20%. Compared to control group (56% ± 11%), IPC reduced infarct size by 46% (30% ± 6%; mean difference, 26%; 95% confidence interval, 19-33; P < .0001), and RIPC reduced infarct size by 29% (40% ± 8%; mean difference, 16%; 95% confidence interval, 9-24; P < .011). Additional application of TXA had no effect on I/R injury and cardioprotection by IPC or RIPC. TXA does not abolish infarct size reduction by IPC or RIPC.

Ryanodine receptor antagonism alleviates skeletal muscle ischemia reperfusion injury by modulating TNF-α and IL-10

BACKGROUND

Intracellular calcium overload has been implicated in various pathological conditions including ischemia reperfusion injury. This study aims to explore the effect and probable mechanism of dantrolene, a ryanodine receptor and intracellular calcium antagonist, on the skeletal muscle ischemia reperfusion injury.

MATERIALS AND METHODS

SD rats were randomly divided into three groups: sham group which underwent anaesthesia and exposure of femoral vein, reperfusion group that received 2 h ischemia and the amount of diluent via femoral vein before 4 h reperfusion, dantrolene group that underwent 2 h ischemia and was given 2 mg/kg dantrolene via femoral vein before 4 h reperfusion. The parameters measured at the end of reperfusion included serum maleic dialdehyde (MDA), tissue myeloperoxidase (MPO) and muscle histology, as well as serum TNF-α and IL-10.

RESULTS

Levels of MDA, MPO and TNF-α increased in the reperfusion group, whereas the relevant expressions in the dantrolene group decreased significantly. Histological examination demonstrated significant improvements between the same both groups. IL-10 reflected the protection observed above with a significant up-regulation of expression after dantrolene administration.

CONCLUSION

Ryanodine receptor antagonist dantrolene exerted a significant protective effect against the inflammatory injury of skeletal muscle ischemia reperfusion. The underlying molecular mechanism is probably related to the suppression of TNF-α levels and the increment of IL-10 expression.

Immunity, Inflammation, and Oxidative Stress in Heart Failure: Emerging Molecular Targets

PURPOSE

Heart failure (HF) remains a major cause of morbidity and mortality worldwide. Although various therapies developed over the last two decades have shown improved long term outcomes in patients with established HF, there has been little progress in preventing the adverse cardiac remodeling that initiates HF. To fill the gap in treatment, current research efforts are focused on understanding novel mechanisms and signaling pathways. Immune activation, inflammation, oxidative stress, alterations in mitochondrial bioenergetics, and autophagy have been postulated as important pathophysiological events in this process. An improved understanding of these complex processes could facilitate a therapeutic shift toward molecular targets that can potentially alter the course of HF.

METHODS

In this review, we address the role of immunity, inflammation, and oxidative stress as well as other novel emerging concepts in the pathophysiology of HF that may have therapeutic implications.

CONCLUSION

Based on the experimental and clinical studies presented here, we anticipate that a better understanding of the pathophysiology of HF will open the door for new therapeutic targets. A one-size-fits-all approach may not be appropriate for all patients with HF, and further clinical trials utilizing molecular targeting in HF may result in improved outcomes.

Eriodictyol Attenuates Myocardial Ischemia-Reperfusion Injury through the Activation of JAK2

Myocardial ischemia-reperfusion (I/R) injury remains the leading risk factor of disability and mortality worldwide. In this study, the myocardial protective effect of eriodictyol (EDT) and the underlying mechanism in an ex vivo model of global myocardial I/R was investigated. After treatment with different concentrations of EDT, the decreased hemodynamic parameters induced by myocardial I/R injury were significantly attenuated by EDT. The elevated levels of IL-6, CRP, IL-8, and TNF-α were effectively reduced by EDT treatment. EDT also remarkably suppressed the levels of Bax and cleaved Caspase-3, and up-regulated the level of Bcl-2 in cardiac tissues from EDT-treated groups. Further studies showed that EDT could increase the levels of p-JAK2 and p-STAT3 in cardiac tissues. Meanwhile, treatment of AG490, a specific inhibitor of JAK2, abolished the protective effect of EDT on hemodynamic parameters, myocardial inflammation and myocardial cell apoptosis induced by I/R injury. These results demonstrated that EDT could protect against myocardial I/R injury through the activation of JAK2, providing a potential treatment with EDT during myocardial I/R injury.

Biochemical targets of drugs mitigating oxidative stress via redox-independent mechanisms

Acute or chronic oxidative stress plays an important role in many pathologies. Two opposite approaches are typically used to prevent the damage induced by reactive oxygen and nitrogen species (RONS), namely treatment either with antioxidants or with weak oxidants that up-regulate endogenous antioxidant mechanisms. This review discusses options for the third pharmacological approach, namely amelioration of oxidative stress by 'redox-inert' compounds, which do not inactivate RONS but either inhibit the basic mechanisms leading to their formation (i.e. inflammation) or help cells to cope with their toxic action. The present study describes biochemical targets of many drugs mitigating acute oxidative stress in animal models of ischemia-reperfusion injury or N-acetyl-p-aminophenol overdose. In addition to the pro-inflammatory molecules, the targets of mitigating drugs include protein kinases and transcription factors involved in regulation of energy metabolism and cell life/death balance, proteins regulating mitochondrial permeability transition, proteins involved in the endoplasmic reticulum stress and unfolded protein response, nuclear receptors such as peroxisome proliferator-activated receptors, and isoprenoid synthesis. The data may help in identification of oxidative stress mitigators that will be effective in human disease on top of the current standard of care.

Shared metabolic and immune-inflammatory, oxidative and nitrosative stress pathways in the metabolic syndrome and mood disorders

This review examines the shared immune-inflammatory, oxidative and nitrosative stress (IO&NS) and metabolic pathways underpinning metabolic syndrome (MetS), bipolar disorder (BD) and major depressive disorder (MDD). Shared pathways in both MetS and mood disorders are low grade inflammation, including increased levels of pro-inflammatory cytokines and acute phase proteins, increased lipid peroxidation with formation of malondialdehyde and oxidized low density lipoprotein cholesterol (LDL-c), hypernitrosylation, lowered levels of antioxidants, most importantly zinc and paraoxonase (PON1), increased bacterial translocation (leaky gut), increased atherogenic index of plasma and Castelli risk indices; and reduced levels of high-density lipoprotein (HDL-c) cholesterol. Insulin resistance is probably not a major factor associated with mood disorders. Given the high levels of IO&NS and metabolic dysregulation in BD and MDD and the high comorbidity with the atherogenic components of the MetS, mood disorders should be viewed as systemic neuro-IO&NS-metabolic disorders. The IO&NS-metabolic biomarkers may have prognostic value and may contribute to the development of novel treatments targeting neuro-immune, neuro-oxidative and neuro-nitrosative pathways.

Anti-Inflammatory Therapeutic Effect of Adiponectin Gene Delivery Using a Polymeric Carrier in an Acute Lung Injury Model

PURPOSE

Adiponectin (APN) is an adipokine with anti-inflammatory and cytoprotective effects. In this study, the therapeutic effect of APN gene delivery using a polymeric carrier was evaluated in an acute lung injury (ALI) model.

METHODS

Polyethylenimine (2 kDa, PEI2K), PEI25K (25 kDa), polyamidoamine (generation 2, PAMG2), dexamethasone-conjugated PEI2k (PEI2K-Dexa), and dexamethasone-conjugated PAMG2 (PAMG2-Dexa) were evaluated in vitro and in vivo as gene carriers. Formation of plasmid DNA (pDNA)/carrier complexes was confirmed by gel retardation and heparin competition assays. Delivery efficiency was measured by a luciferase assay and fluorescence microscopy. In an ALI animal model, pAPN/carrier complexes were delivered by intratracheal administration. Therapeutic effects were evaluated by cytokine assays and hematoxylin and eosin (H&E) staining.

RESULTS

Gel retardation assays showed that PEI2K-Dexa and PAMG2-Dexa formed complexes with pDNA. In L2 lung epithelial cells, PAMG2-Dexa yielded higher transfection efficiency than PEI2K, PAMG2, PEI25K, lipofectamine, and PEI2K-Dexa. In vivo experiments showed that PAMG2-Dexa delivered DNA more efficiently to lung tissue than PEI2K-Dexa and PEI25K. Delivery of pAPN/PAMG2-Dexa complexes upregulated APN expression in the lungs of mice with ALI. As a result, the levels of pro-inflammatory cytokines such as TNF-α and IL-1β were decreased. H&E staining showed that inflammation in the lungs of mice with ALI was reduced by delivery of the APN gene.

CONCLUSION

Delivery of the APN gene using PAMG2-Dexa reduced inflammation in the lungs of mice with ALI. The APN gene could be a useful tool in the development of gene therapy for ALI.

The Role of Peroxisome Proliferator-Activated Receptor γ in Mediating Cardioprotection Against Ischemia/Reperfusion Injury

Myocardial infarction (MI) is a serious cardiovascular disease resulting in high rates of morbidity and mortality. Although advances have been made in restoring myocardial perfusion in ischemic areas, decreases in cardiomyocyte death and infarct size are still limited, attributing to myocardial ischemia/reperfusion (I/R) injury. It is necessary to develop therapies to restrict myocardial I/R injury and protect cardiomyocytes against further damage after MI. Many studies have suggested that peroxisome proliferator-activated receptor γ (PPARγ), a ligand-inducible nuclear receptor that predominantly regulates glucose and lipid metabolism, is a promising therapeutic target for ameliorating myocardial I/R injury. Thus, this review focuses on the role of PPARγ in cardioprotection during myocardial I/R. The cardioprotective effects of PPARγ, including attenuating oxidative stress, inhibiting inflammatory responses, improving glucose and lipid metabolism, and antagonizing apoptosis, are described. Additionally, the underlying mechanisms of cardioprotective effects of PPARγ, such as regulating the expression of target genes, influencing other transcription factors, and modulating kinase signaling pathways, are further discussed.

Ilexsaponin A attenuates ischemia-reperfusion-induced myocardial injury through anti-apoptotic pathway

The protective effects of ilexsaponin A on ischemia-reperfusion-induced myocardial injury were investigated. Myocardial ischemia/reperfusion model was established in male Sprague–Dawley rats. Myocardial injury was evaluated by TTC staining and myocardial marker enzyme leakage. The in vitro protective potential of Ilexsaponin A was assessed on hypoxia/reoxygenation cellular model in neonatal rat cardiomyocytes. Cellular viability and apoptosis were evaluated by MTT and TUNEL assay. Caspase-3, cleaved caspase-3, bax, bcl-2, p-Akt and Akt protein expression levels were detected by western-blot. Ilexsaponin A treatment was able to attenuate the myocardial injury in ischemia/reperfusion model by reducing myocardial infarct size and lower the serum levels of LDH, AST and CK-MB. The in vitro study also showed that ilexsaponin A treatment could increase cellular viability and inhibit apoptosis in hypoxia/reoxygenation cardiomyocytes. Proapoptotic proteins including caspase-3, cleaved caspase-3 and bax were significantly reduced and anti-apoptotic protein bcl-2 was significantly increased by ilexsaponin A treatment in hypoxia/reoxygenation cardiomyocytes. Moreover, Ilexsaponin A treatment was able to increase the expression levels of p-Akt in hypoxia/reoxygenation cellular model and myocardial ischemia/reperfusion animal model. Coupled results from both in vivo and in vitro experiments indicate that Ilexsaponin A attenuates ischemia-reperfusion-induced myocardial injury through anti-apoptotic pathway.

Inhibition of PKR protects against H2O2-induced injury on neonatal cardiac myocytes by attenuating apoptosis and inflammation

Reactive oxygenation species (ROS) generated from reperfusion results in cardiac injury through apoptosis and inflammation, while PKR has the ability to promote apoptosis and inflammation. The aim of the study was to investigate whether PKR is involved in hydrogen peroxide (H₂O₂) induced neonatal cardiac myocytes (NCM) injury. In our study, NCM, when exposed to H₂O₂, resulted in persistent activation of PKR due to NCM endogenous RNA. Inhibition of PKR by 2-aminopurine (2-AP) or siRNA protected against H₂O₂ induced apoptosis and injury. To elucidate the mechanism, we revealed that inhibition of PKR alleviated H₂O₂ induced apoptosis companied by decreased caspase3/7 activity, BAX and caspase-3 expression. We also revealed that inhibition of PKR suppressed H₂O₂ induced NFκB pathway and NLRP3 activation. Finally, we found ADAR1 mRNA and protein expression were both induced after H₂O₂ treatment through STAT-2 dependent pathway. By gain and loss of ADAR1 expression, we confirmed ADAR1 modulated PKR activity. Therefore, we concluded inhibition of PKR protected against H₂O₂-induced injury by attenuating apoptosis and inflammation. A self-preservation mechanism existed in NCM that ADAR1 expression is induced by H₂O₂ to limit PKR activation simultaneously. These findings identify a novel role for PKR/ADAR1 in myocardial reperfusion injury.

High Serum Tumor Necrosis Factor Levels in the Early Post-Cardiac Arrest Period Are Associated with Poor Short-Term Survival in a Swine Model of Ventricular Fibrillation

Most resuscitated victims of out-of-hospital cardiac arrest who survive to hospital expire due to the postresuscitation syndrome. This syndrome is characterized by a sepsis-like proinflammatory state. The objective of this investigation was to determine whether a relationship exists between the rise of tumor necrosis factor (TNF), a proinflammatory cytokine, following return of spontaneous circulation (ROSC), and early postarrest survival in a clinically relevant animal model of spontaneous ventricular fibrillation (VF). Mixed-breed Yorkshire swine (n = 20), weighing 39 ± 5 kg, were anesthetized and catheters placed in the right atrium and left ventricle/ascending aorta for continuous pressure monitoring. VF was induced by occluding the left anterior descending coronary artery with an angioplasty balloon. After 7 min of untreated VF, advanced life support resuscitation attempts were made for up to 20 min. Animals achieving ROSC were monitored for 3 h and fluid and pressor support was administered as needed. TNF levels were measured before VF and at 0, 15, and 30 min after ROSC using quantitative sandwich enzyme-linked immunosorbent assay. Twelve (60%) animals experienced early death, expiring during the 3 hour postarrest period (9 pulseless electrical activity, 2 VF, and 1 asystole). The TNF level at 15 min post-ROSC was significantly associated with death within the first 3 h post-ROSC with a univariate odds ratio of 1.4 [95% confidence interval (CI) 1.05-2.2, P = 0.01]. Using a cutoff TNF level of 525 pg/mL at 15 min post-ROSC had 100% negative predictive value (95% CI 0%-37%) and 67% positive predictive value (95% CI 35%-90%) for early death with a hazard ratio of 6.6 (95% CI 1.9-23.5). TNF increases shortly after ROSC and is predictive of early death. Early identification of resuscitated victims at greatest risk for hemodynamic collapse and recurrent arrest might facilitate the use of early hospital-based interventions to decrease the likelihood of a poor outcome.

Direct Evidence that Myocardial Insulin Resistance following Myocardial Ischemia Contributes to Post-Ischemic Heart Failure

A close link between heart failure (HF) and systemic insulin resistance has been well documented, whereas myocardial insulin resistance and its association with HF are inadequately investigated. This study aims to determine the role of myocardial insulin resistance in ischemic HF and its underlying mechanisms. Male Sprague-Dawley rats subjected to myocardial infarction (MI) developed progressive left ventricular dilation with dysfunction and HF at 4 wk post-MI. Of note, myocardial insulin sensitivity was decreased as early as 1 wk after MI, which was accompanied by increased production of myocardial TNF-α. Overexpression of TNF-α in heart mimicked impaired insulin signaling and cardiac dysfunction leading to HF observed after MI. Treatment of rats with a specific TNF-α inhibitor improved myocardial insulin signaling post-MI. Insulin treatment given immediately following MI suppressed myocardial TNF-α production and improved cardiac insulin sensitivity and opposed cardiac dysfunction/remodeling. Moreover, tamoxifen-induced cardiomyocyte-specific insulin receptor knockout mice exhibited aggravated post-ischemic ventricular remodeling and dysfunction compared with controls. In conclusion, MI induces myocardial insulin resistance (without systemic insulin resistance) mediated partly by ischemia-induced myocardial TNF-α overproduction and promotes the development of HF. Our findings underscore the direct and essential role of myocardial insulin signaling in protection against post-ischemic HF.