Heart Failure

Mitofilin in cardiovascular diseases: Insights into the pathogenesis and potential pharmacological interventions

The impact of mitochondrial dysfunction on the pathogenesis of cardiovascular disease is increasing. However, the precise underlying mechanism remains unclear. Mitochondria produce cellular energy through oxidative phosphorylation while regulating calcium homeostasis, cellular respiration, and the production of biosynthetic chemicals. Nevertheless, problems related to cardiac energy metabolism, defective mitochondrial proteins, mitophagy, and structural changes in mitochondrial membranes can cause cardiovascular diseases via mitochondrial dysfunction. Mitofilin is a critical inner mitochondrial membrane protein that maintains cristae structure and facilitates protein transport while linking the inner mitochondrial membrane, outer mitochondrial membrane, and mitochondrial DNA transcription. Researchers believe that mitofilin may be a therapeutic target for treating cardiovascular diseases, particularly cardiac mitochondrial dysfunctions. In this review, we highlight current findings regarding the role of mitofilin in the pathogenesis of cardiovascular diseases and potential therapeutic compounds targeting mitofilin.

Serum osmolality and hyperosmolar states

Serum osmolality is the sum of the osmolalities of every single dissolved particle in the blood such as sodium and associated anions, potassium, glucose, and urea. Under normal conditions, serum sodium concentration is the major determinant of serum osmolality. Effective blood osmolality, so-called blood tonicity, is created by the endogenous (e.g., sodium and glucose) and exogenous (e.g., mannitol) solutes that are capable of creating an osmotic gradient across the membranes. In case of change in effective blood osmolality, water shifts from the compartment with low osmolality into the compartment with high osmolarity in order to restore serum osmolality. The difference between measured osmolality and calculated osmolarity forms the osmolal gap. An increase in serum osmolal gap can stem from the presence of solutes that are not included in the osmolarity calculation, such as hypertonic treatments or toxic alcoholic ingestions. In clinical practice, determination of serum osmolality and osmolal gap is important in the diagnosis of disorders related to sodium, glucose and water balance, kidney diseases, and small molecule poisonings. As blood hypertonicity exerts its main effects on the brain cells, neurologic symptoms varying from mild neurologic signs and symptoms to life-threatening outcomes such as convulsions or even death may occur. Therefore, hypertonic states should be promptly diagnosed and cautiously managed. In this review, the causes and treatment strategies of hyperosmolar conditions including hypernatremia, diabetic ketoacidosis, hyperglycemic hyperosmolar syndrome, hypertonic treatments, or intoxications are discussed in detail to increase awareness of this important topic with significant clinical consequences.

Crosstalk between microRNA and Oxidative Stress in Heart Failure: A Systematic Review

Heart failure is defined as a clinical syndrome consisting of key symptoms and is due to a structural and/or functional alteration of the heart that results in increased intracardiac pressures and/or inadequate cardiac output at rest and/or during exercise. One of the key mechanisms determining myocardial dysfunction in heart failure is oxidative stress. MicroRNAs (miRNAs, miRs) are short, endogenous, conserved, single-stranded non-coding RNAs of around 21-25 nucleotides in length that act as regulators of multiple processes. A systematic review following the PRISMA guidelines was performed on the evidence on the interplay between microRNA and oxidative stress in heart failure. A search of Pubmed, Embase, Scopus, and Scopus direct databases using the following search terms: 'heart failure' AND 'oxidative stress' AND 'microRNA' or 'heart failure' AND 'oxidative stress' AND 'miRNA' was conducted and resulted in 464 articles. Out of them, 15 full text articles were eligible for inclusion in the qualitative analysis. Multiple microRNAs are involved in the processes associated with oxidative stress leading to heart failure development including mitochondrial integrity and function, antioxidant defense, iron overload, ferroptosis, and survival pathways.

Mechanism of CREB1 in cardiac function of rats with heart failure via regulating the microRNA-376a-3p/TRAF6 axis

Heart failure (HF) is a complicated disease resulting from impaired heart function. CREB1 is a candidate target in heart-concerning diseases. This paper attempts to explore the role of CREB1 in HF. Initially, the HF rat model was established by constricted abdominal aortic surgery and the cardiac function of HF rats was assessed by ultrasonic cardiogram. Levels of CK-MB and LDH and activity of Caspase-3 and Caspase-9 in HF rats were determined. Subsequently, myocardium pathological injury and myocardium apoptosis were detected. Additionally, the interactions between CREB1 and miR-376a-3p and between miR-376a-3p and TRAF6 were verified. The roles of CREB1, miR-376a-3p, and TRAF6 in HF were evaluated. In HF rats, CREB1 and miR-376a-3p were both downregulated while TRAF6 was upregulated. Besides, HF rats had decreased values of EF and FS, elevated levels of CK-MB and LDH, inflammatory infiltration, promoted cardiomyocyte apoptosis, and elevated activity of Caspase-3 and Caspase-9, which were all reversed by CREB1. Additionally, CREB1 activated miR-376a-3p expression, and miR-376a-3p targeted TRAF6 transcription. Both miR-376a-3p knockdown and TRAF6 overexpression annulled the protective role of CREB1 overexpression in cardiac function of HF rats. CREB1 activated miR-376a-3p expression to suppress TRAF6, thereby promoting the cardiac function of HF rats.

Cardiovascular Magnetic Resonance Imaging: A Prospective Modality in the Diagnosis and Prognostication of Heart Failure

Heart failure (HF) is a clinical syndrome resulting from structural cardiac remodeling and altered function that impairs tissue perfusion. This article aimed to highlight the current diagnostic and prognostic value of cardiac magnetic resonance (CMR) in the management of HF and prospective future applications. Reviewed are the physics associated with CMR, its use in ischemic and non-ischemic causes of HF, and its role in quantifying left ventricular ejection fraction. It also emphasized that CMR allows for noninvasive morphologic and functional assessment, tissue characterization, blood flow, and perfusion evaluation in patients with suspected or diagnosed HF. CMR has become a crucial instrument for the diagnosis, prognosis, and therapy planning in patients with HF and cardiomyopathy due to its accuracy in quantifying cardiac volumes and ejection fraction (considered the gold standard) as well as native and post-contrast myocardial tissue characterization.

Disturbance of myocardial metabolism participates in autoantibodies against β1 -adrenoceptor-induced cardiac dysfunction

Cardiac dysfunction is involved in disorders of energy metabolism. High-titre autoantibodies against the β1 -adrenoceptor (β1 -AAs) have been reported to exist in patients with cardiac dysfunction; however, the mechanism by which β1 -AAs affect cardiac function is unknown. This study aimed to determine whether β1 -AAs disturb myocardium energy metabolism and cause cardiac dysfunction. β1 -AA monoclonal antibodies (β1 -AAmAbs) were successfully pre-synthesized by hybridoma clones and used in all experiments. β1 -AAmAbs impaired cardiac function and induced a myocardial metabolic disturbance, as evidenced by decreased left ventricular ejection fraction and fractional shortening. In addition, β1 -AAmAbs decreased the adenosine triphosphate level and increased cardiac energy consumption (rate-pressure product). We further showed that the effects of β1 -AAmAbs on heart tissue might involve the mitochondria and metabolic pathways via the β1 -adrenoceptor based on an immunoprecipitation and mass spectrometry. Additionally, we found that β1 -AAmAbs impaired myocardial mitochondrial structure, decreased the membrane potential, and induced insufficient mitophagy. In conclusion, β1 -AAmAb-induced cardiac dysfunction is partly due to a disturbance in myocardial energy metabolism.