Mitochondrial Dysfunction in the Cardio-Renal Axis

Cardiovascular disease (CVD) frequently complicates chronic kidney disease (CKD). The risk of all-cause mortality increases from 20% to 500% in patients who suffer both conditions; this is referred to as the so-called cardio-renal syndrome (CRS). Preclinical studies have described the key role of mitochondrial dysfunction in cardiovascular and renal diseases, suggesting that maintaining mitochondrial homeostasis is a promising therapeutic strategy for CRS. In this review, we explore the malfunction of mitochondrial homeostasis (mitochondrial biogenesis, dynamics, oxidative stress, and mitophagy) and how it contributes to the development and progression of the main vascular pathologies that could be affected by kidney injury and vice versa, and how this knowledge may guide the development of novel therapeutic strategies in CRS.

Perspectives on mitochondrial relevance in cardiac ischemia/reperfusion injury

Cardiovascular disease is the most common cause of death worldwide and in particular, ischemic heart disease holds the most considerable position. Even if it has been deeply studied, myocardial ischemia-reperfusion injury (IRI) is still a side-effect of the clinical treatment for several heart diseases: ischemia process itself leads to temporary damage to heart tissue and obviously the recovery of blood flow is promptly required even if it worsens the ischemic injury. There is no doubt that mitochondria play a key role in pathogenesis of IRI: dysfunctions of these important organelles alter cell homeostasis and survival. It has been demonstrated that during IRI the system of mitochondrial quality control undergoes alterations with the disruption of the complex balance between the processes of mitochondrial fusion, fission, biogenesis and mitophagy. The fundamental role of mitochondria is carried out thanks to the finely regulated connection to other organelles such as plasma membrane, endoplasmic reticulum and nucleus, therefore impairments of these inter-organelle communications exacerbate IRI. This review pointed to enhance the importance of the mitochondrial network in the pathogenesis of IRI with the aim to focus on potential mitochondria-targeting therapies as new approach to control heart tissue damage after ischemia and reperfusion process.

Review of lipoic acid: From a clinical therapeutic agent to various emerging biomaterials

Lipoic acid (LA), an endogenous small molecule in organisms, has been extensively used for the highly efficient clinical treatment of malignant diseases, which include diabetes, Alzheimer's disease, and cancer over the past seven decades. Tremendous progresses have been made on the use of LA in nanomedicine for the development of various biomaterials because of its unique biological properties and highly adaptable structure since the first discovery. However, there are few reviews thus far, to our knowledge, summarizing this hot subject of research of LA and its derived biomaterials. For this purpose, we present herein the first comprehensive summary on the design and development of LA and its derived materials for biomedical applications. This review first discusses the therapeutic use of LA followed by the description of synthesis and preclinical study of LA-derived-small molecules. The applications of various LA and poly (lipoic acid) (PLA)-derived-biomaterials are next summarized in detail with an emphasis on the use of LA for the design of biomaterials and the diverse properties. This review describes the development of LA from a clinical therapeutic agent to a building unit of various biomaterials field, which will promote the further discovery of new therapeutic uses of LA as therapeutic agents and facile development of LA-based derivates with greater performance for biomedical applications.

SUPPORT-1 (Subjects Undergoing PCI and Perioperative Reperfusion Treatment): A Prospective, Randomized Trial of CMX-2043 in Patients Undergoing Elective Percutaneous Coronary Intervention

OBJECTIVE

The natural molecule α-lipoic acid has been shown to be partially cytoprotective through antioxidant and antiapoptotic mechanisms. To obtain an initial assessment of the safety and potential efficacy of a synthetic derivative, CMX-2043, in preventing ischemic complications of percutaneous coronary intervention (PCI) we conducted the Subjects Undergoing PCI and Perioperative Reperfusion Treatment (SUPPORT-1) trial, the first patient experience with this agent.

METHODS AND RESULTS

SUPPORT-1 was a phase 2a, 6-center, international, placebo-controlled, randomized, double-blind trial. A total of 142 patients were randomized to receive a single intravenous bolus dose of drug or placebo administered 15-60 minutes before PCI. Cardiac biomarker assessments included serial measurements of creatine kinase myocardial band (CK-MB) at 6, 12, 18, and 24 hours after PCI and a single measurement of troponin T (TnT) at 24 hours. Peak concentrations of CK-MB and TnT were significantly reduced in the 2.4 mg/kg group compared with placebo (P = 0.05 and 0.03, respectively). No subject administered 2.4 mg/kg of CMX-2043 had an increase of CK-MB to ≥3X upper limit of normal versus 16% for placebo (P = 0.02); 16% of the 2.4-mg/kg dose group developed an elevation of TnT to ≥3X upper limit of normal versus 39% in the placebo group (P = 0.05). No drug-related serious adverse events were observed in any group.

CONCLUSION

These data suggest that CMX-2043 may reduce PCI periprocedural myonecrosis and support further clinical evaluation of this novel agent for its potential cytoprotective effects.

Mitochondria as a therapeutic target for cardiac ischemia‑reperfusion injury (Review)

Acute myocardial infarction is the leading cause of cardiovascular-related mortality and chronic heart failure worldwide. As regards treatment, the reperfusion of ischemic tissue generates irreversible damage to the myocardium, which is termed 'cardiac ischemia-reperfusion (IR) injury'. Due to the large number of mitochondria in cardiomyocytes, an increasing number of studies have focused on the roles of mitochondria in IR injury. The primary causes of IR injury are reduced oxidative phosphorylation during hypoxia and the increased production of reactive oxygen species (ROS), together with the insufficient elimination of these oxidative species following reperfusion. IR injury includes the oxidation of DNA, incorrect modifications of proteins, the disruption of the mitochondrial membrane and respiratory chain, the loss of mitochondrial membrane potential (∆Ψm), Ca²⁺ over-load, mitochondrial permeability transition pore formation, swelling of the mitochondria, and ultimately, cardiomyocyte necrosis. The present review article discusses the molecular mechanisms of IR injury, and summarizes the metabolic and dynamic changes occurring in the mitochondria in response to IR stress. The mitochondria are strongly recommended as a target for the development of therapeutic agents; however, the appropriate use of agents remains a challenge.

Protective effects of N(2)‑L‑alanyl‑L‑glutamine mediated by the JAK2/STAT3 signaling pathway on myocardial ischemia reperfusion

To explore the protective effect of N(2)-L-alanyl-L-glutamine (NLAG) on myocardial ischemia-reperfusion injury (IRI), and observe the influence of NLAG on the Janus activated kinase signal transducer 2 and activator of transcription 3 (JAK2/STAT3) signaling pathway‑associated molecules. Wistar rats were randomly divided into three groups: Sham, IRI and NLAG. In the IRI rat model, the cardiac hemodynamics, the maximum rate of left ventricular pressure (+dP/dtmax) and the left ventricular end‑diastolic pressure (LVDP) were recorded. Hematoxylin‑eosin and Masson staining were used to detect myocardial histological changes. The levels of plasma interleukin (IL)‑1β and ‑6, tumor necrosis factor (TNF)‑α, lactase dehydrogenase (LDH), troponin (cTn)I, creatine kinase (CK), heart type fatty acid binding protein (hFABP), malondialdehyde (MDA) and succinate dehydrogenase (SDH) were determined with ELISA. The protein expression levels of B‑cell lymphoma (Bcl)‑2, Bcl2‑associated X protein (Bax), Caspase‑3, JAK2, phosphorylated (p)‑JAK2, STAT3 and p‑STAT3 were detected by western blot analysis. The IRI model demonstrated notable myocardial injury; myocardial cells were arranged disorderly with some nuclei disappearing, and cardiac muscular fibers were degenerated. Following 60 min of reperfusion, LVDP, HR and +dP/dtmax were 31.3±4.53 mmHg, 239.17±8.45 beats/min and 615.17 mmHg/sec, respectively. Compared with the Sham group, the levels of LDH, cTnI, CK, hFABP release, inflammatory factors (IL‑1β, IL‑6 and TNF‑α) and oxygen free radical (MDA and SDH) levels were increased in the IRI group. In the NLAG group, myocardial injury was improved, the concentrations of LDH, cTnI, CK, hFABP, IL‑1β, IL‑6, TNF‑α, MDA were decreased, and SDH release was increased compared with the IRI group. In addition, NLAG significantly increased Bcl‑2, JAK2, p‑JAK2, STAT3 and p‑STAT3 protein expression, and decreased Bax protein expression compared with the IRI group. In conclusion, myocardial ischemia‑reperfusion can lead to myocardial cell apoptosis and myocardial injury and NLAG attenuates the IRI‑induced mitochondrial oxidative stress injury and apoptosis by activating the JAK2/STAT3 signaling pathway, thus exerting protective effects against IRI.

CMX-2043 Mechanisms of Action In Vitro

α-Lipoic acid has been shown to provide cytoprotection in some tissues through antioxidant and antiapoptotic mechanisms. We have enhanced these properties by synthetic modification, resulting in a new chemical entity, CMX-2043, with proven efficacy in an animal model of cardiac ischemia-reperfusion injury. The present studies compare cytoprotective cellular pathways of R-α-lipoic acid and CMX-2043. Biochemical and cellular assays were used to compare antioxidant potency, tyrosine kinase activation, and protein kinase B (Akt) phosphorylation. CMX-2043 was more effective than lipoic acid in antioxidant effect, activation of insulin receptor kinase, soluble tyrosine kinase, and Akt phosphorylation. Activation of insulin-like growth factor 1 receptor was similar for both. CMX-2043 stimulation of Akt phosphorylation was abolished by the phosphatidylinositide 3-kinase inhibitor LY294002. Consistent with Akt activation, CMX-2043 reduced carbachol-induced calcium overload. The S-stereoisomer of CMX-2043 was less active in the biochemical assays than the R-isomer. These results are consistent with cytoprotection through activation of Akt and antioxidant action. CMX-2043 may thus provide a pharmacological approach to cytoprotection consistent with established anti-apoptotic mechanisms.