Cardiac myosin-binding protein C as a biomarker of acute myocardial infarction

Curcumin mitigates gentamicin induced-renal and cardiac toxicity via modulation of Keap1/Nrf2, NF-κB/iNOS and Bcl-2/BAX pathways

Gentamicin (GEN) is an aminoglycoside antibiotic used to treat gram-negative bacterial infections. Our study aimed to explore curcumin's (CMN) protective role against GEN-induced renal and cardiac toxicity. Rats were randomly classified into 4 equal groups; Control (cont), GEN (100 mg/kg b.wt, i.p.) for seven days, CMN (200 mg/kg b.wt, orally) for 21 days, and CMN + GEN groups. GEN caused renal and cardiac dysfunctions; increased urea, creatinine, uric acid, cystatin C, CK-MB, LDH, and troponin I serum levels. MDA level was elevated significantly while activities of SOD, CAT, and GSH level were reduced significantly in renal and cardiac tissues. GEN-intoxicated rats showed up-regulation of NF-κB, IL-1β, Keap1, HMOX1, and BAX with down-regulation of Nrf2, and Bcl-2 mRNA expression in renal and cardiac tissues. Also, GEN-induced up-regulation of renal mRNA expression of KIM-1, NGAL, and intermediate filament proteins [desmin, nestin, and vimentin] as well cardiac gene expression of cMyBP-C and H-FABP. GEN-induced toxicity was significantly attenuated by CMN co-treatment as CMN improved renal and cardiac biomarkers, reduced oxidative stress and inflammatory response, and reversed alterations in mRNA expression of all tested renal and cardiac genes. These outcomes indicated that CMN could protect renal and cardiac tissues against GEN-induced oxidative stress, inflammation, and apoptosis.

Etiology of genetic muscle disorders induced by mutations in fast and slow skeletal MyBP-C paralogs

Skeletal muscle, a highly complex muscle type in the eukaryotic system, is characterized by different muscle subtypes and functions associated with specific myosin isoforms. As a result, skeletal muscle is the target of numerous diseases, including distal arthrogryposes (DAs). Clinically, DAs are a distinct disorder characterized by variation in the presence of contractures in two or more distal limb joints without neurological issues. DAs are inherited, and up to 40% of patients with this condition have mutations in genes that encode sarcomeric protein, including myosin heavy chains, troponins, and tropomyosin, as well as myosin binding protein-C (MYBPC). Our research group and others are actively studying the specific role of MYBPC in skeletal muscles. The MYBPC family of proteins plays a critical role in the contraction of striated muscles. More specifically, three paralogs of the MYBPC gene exist, and these are named after their predominant expression in slow-skeletal, fast-skeletal, and cardiac muscle as sMyBP-C, fMyBP-C, and cMyBP-C, respectively, and encoded by the MYBPC1, MYBPC2, and MYBPC3 genes, respectively. Although the physiology of various types of skeletal muscle diseases is well defined, the molecular mechanism underlying the pathological regulation of DAs remains to be elucidated. In this review article, we aim to highlight recent discoveries involving the role of skeletal muscle-specific sMyBP-C and fMyBP-C as well as their expression profile, localization in the sarcomere, and potential role(s) in regulating muscle contractility. Thus, this review provides an overall summary of MYBPC skeletal paralogs, their potential roles in skeletal muscle function, and future research directions.

Implications of S-glutathionylation of sarcomere proteins in cardiac disorders, therapies, and diagnosis

The discovery that cardiac sarcomere proteins are substrates for S-glutathionylation and that this post-translational modification correlates strongly with diastolic dysfunction led to new concepts regarding how levels of oxidative stress affect the heartbeat. Major sarcomere proteins for which there is evidence of S-glutathionylation include cardiac myosin binding protein C (cMyBP-C), actin, cardiac troponin I (cTnI) and titin. Our hypothesis is that these S-glutathionylated proteins are significant factors in acquired and familial disorders of the heart; and, when released into the serum, provide novel biomarkers. We consider the molecular mechanisms for these effects in the context of recent revelations of how these proteins control cardiac dynamics in close collaboration with Ca2+ fluxes. These revelations were made using powerful approaches and technologies that were focused on thin filaments, thick filaments, and titin filaments. Here we integrate their regulatory processes in the sarcomere as modulated mainly by neuro-humoral control of phosphorylation inasmuch evidence indicates that S-glutathionylation and protein phosphorylation, promoting increased dynamics and modifying the Frank-Starling relation, may be mutually exclusive. Earlier studies demonstrated that in addition to cTnI as a well-established biomarker for cardiac disorders, serum levels of cMyBP-C are also a biomarker for cardiac disorders. We describe recent studies approaching the question of whether serum levels of S-glutathionylated-cMyBP-C could be employed as an important clinical tool in patient stratification, early diagnosis in at risk patients before HFpEF, determination of progression, effectiveness of therapeutic approaches, and as a guide in developing future therapies.

Cardiac Complications of Hypertensive Emergency: Classification, Diagnosis and Management Challenges

While mortality in patients with hypertensive emergency has significantly improved over the past decades, the incidence and complications associated with acute hypertension-mediated organ damage have not followed a similar trend. Hypertensive emergency is characterized by an abrupt surge in blood pressure, mostly occurring in people with pre-existing hypertension to result in acute hypertension-mediated organ damage. Acute hypertension-mediated organ damage commonly affects the cardiovascular system, and present as acute heart failure, myocardial infarction, and less commonly, acute aortic syndrome. Elevated cardiac troponin with or without myocardial infarction is one of the major determinants of outcome in hypertensive emergency. Despite being an established entity distinct from myocardial infarction, myocardial injury has not been systematically studied in hypertensive emergency. The current guidelines on the evaluation and management of hypertensive emergencies limit the cardiac troponin assay to patients presenting with features of myocardial ischemia and acute coronary syndrome, resulting in underdiagnosis, especially of atypical myocardial infarction. In this narrative review, we aimed to give an overview of the epidemiology and pathophysiology of hypertensive emergencies, highlight challenges in the evaluation, classification, and treatment of hypertensive emergency, and propose an algorithm for the evaluation and classification of cardiac acute hypertension-mediated organ damage.

From Classic to Modern Prognostic Biomarkers in Patients with Acute Myocardial Infarction

Despite all the important advances in its diagnosis and treatment, acute myocardial infarction (AMI) is still one of the most prominent causes of morbidity and mortality worldwide. Early identification of patients at high risk of poor outcomes through the measurement of various biomarker concentrations might contribute to more accurate risk stratification and help to guide more individualized therapeutic strategies, thus improving prognoses. The aim of this article is to provide an overview of the role and applications of cardiac biomarkers in risk stratification and prognostic assessment for patients with myocardial infarction. Although there is no ideal biomarker that can provide prognostic information for risk assessment in patients with AMI, the results obtained in recent years are promising. Several novel biomarkers related to the pathophysiological processes found in patients with myocardial infarction, such as inflammation, neurohormonal activation, myocardial stress, myocardial necrosis, cardiac remodeling and vasoactive processes, have been identified; they may bring additional value for AMI prognosis when included in multi-biomarker strategies. Furthermore, the use of artificial intelligence algorithms for risk stratification and prognostic assessment in these patients may have an extremely important role in improving outcomes.