Novel therapies in acute and chronic heart failure

The Renin-Angiotensin System as a Component of Biotrauma in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a major concern in critical care medicine with a high mortality of over 30%. Injury to the lungs is caused not only by underlying pathological conditions such as pneumonia, sepsis, or trauma, but also by ventilator-induced lung injury (VILI) resulting from high positive pressure levels and a high inspiratory oxygen fraction. Apart from mechanical factors that stress the lungs with a specific physical power and cause volutrauma and barotrauma, it is increasingly recognized that lung injury is further aggravated by biological mediators. The COVID-19 pandemic has led to increased interest in the role of the renin-angiotensin system (RAS) in the context of ARDS, as the RAS enzyme angiotensin-converting enzyme 2 serves as the primary cell entry receptor for severe acute respiratory syndrome (SARS) coronavirus (CoV)-2. Even before this pandemic, studies have documented the involvement of the RAS in VILI and its dysregulation in clinical ARDS. In recent years, analytical tools for RAS investigation have made major advances based on the optimized precision and detail of mass spectrometry. Given that many clinical trials with pharmacological interventions in ARDS were negative, RAS-modifying drugs may represent an interesting starting point for novel therapeutic approaches. Results from animal models have highlighted the potential of RAS-modifying drugs to prevent VILI or treat ARDS. While these drugs have beneficial pulmonary effects, the best targets and application forms for intervention still have to be determined to avoid negative effects on the circulation in clinical settings.

Omecamtiv mecarbil treatment improves post-resuscitation cardiac function and neurological outcome in a rat model

Background

Myocardial dysfunction is a major cause of poor outcomes in the post-cardiac arrest period. Omecamtiv mecarbil (OM) is a selective small molecule activator of cardiac myosin that prolongs myocardial systole and increases stroke volume without apparent effects on myocardial oxygen demand. OM administration is safe and improves cardiac function in patients with acute heart failure. Whether OM improves post-resuscitation myocardial dysfunction remains unclear. This study investigated the effect of OM treatment on post-resuscitation myocardial dysfunction and outcomes.

Methods and results

Adult male rats were resuscitated after 9.5 min of asphyxia-induced cardiac arrest. OM and normal saline was continuously intravenously infused after return of spontaneous circulation (ROSC) at 0.25 mg/kg/h for 4 h in the experimental group and control group, respectively (n = 20 in each group). Hemodynamic parameters were measured hourly and monitored for 4 h after cardiac arrest. Recovery of neurological function was evaluated by neurological functioning scores (0–12; favorable: 11–12) for rats 72 h after cardiac arrest. OM treatment prolonged left ventricular ejection time and improved post-resuscitation cardiac output. Post-resuscitation heart rate and left ventricular systolic function (dp/dt₄₀) were not different between groups. Kaplan-Meier analysis showed non-statistically higher 72-h survival in the OM group (72.2% [13/18] and 58.8% [10/17], p = 0.386). The OM group had a higher chance of having favorable neurological outcomes in surviving rats 72 h after cardiac arrest (84.6% [11/13] vs. 40% [4/10], p = 0.026). The percentage of damaged neurons was lower in the OM group in a histology study at 72 h after cardiac arrest (55.5±2.3% vs. 76.2±10.2%, p = 0.004).

Conclusions

OM treatment improved post-resuscitation myocardial dysfunction and neurological outcome in an animal model. These findings support further pre-clinical studies to improve outcomes in post-cardiac arrest care.

Membrane stabilizer Poloxamer 188 improves yield of primary isolated rat cardiomyocytes without impairing function

Intact cardiomyocytes are used to investigate cardiac contractility and evaluate the efficacy of new therapeutic compounds. Primary enzymatic isolation of adult rodent cardiomyocytes has limitations, including low cardiomyocyte survival, which is likely due to ischemic conditions and/or membrane damage. The addition of Poloxamer 188 (P188) has been used to reduce ischemia- and membrane-related damage in ischemia-reperfusion and muscular dystrophy studies. P188 stabilizes membranes, reducing cell death. Cardiomyocytes were isolated from rats, under three conditions: (1) using standard isolation solutions, (2) with P188 added during cannulation (ischemic event), and (3) with P188 added during cannulation, enzymatic digestion, and trituration. Cell survival was assessed by quantifying the number of rod-shaped versus contracted cells on the day of isolation and up to 3 days post-isolation. Adding P188 only during cannulation yielded improved survival on the day of isolation. Little difference in survival was seen among the three conditions in the days post-isolation. Cardiomyocyte function was assessed by measuring calcium transients and unloaded sarcomere lengths for up to 2 days post-isolation. P188 did not consistently alter calcium handling or sarcomere shortening in the isolated cardiomyocytes. We conclude that the addition of P188 to the cannulation (e.g., wash) of the isolated heart may improve initial survival of cardiomyocytes upon primary enzymatic isolation.

Shock - Classification and Pathophysiological Principles of Therapeutics

The management of patients with shock is extremely challenging because of the myriad of possible clinical presentations in cardiogenic shock, septic shock and hypovolemic shock and the limitations of contemporary therapeutic options. The treatment of shock includes the administration of endogenous catecholamines (epinephrine, norepinephrine, and dopamine) as well as various vasopressor agents that have shown efficacy in the treatment of the various types of shock. In addition to the endogenous catecholamines, dobutamine, isoproterenol, phenylephrine, and milrinone have served as the mainstays of shock therapy for several decades. Recently, experimental studies have suggested that newer agents such as vasopressin, selepressin, calcium-sensitizing agents like levosimendan, cardiac-specific myosin activators like omecamtiv mecarbil (OM), istaroxime, and natriuretic peptides like nesiritide can enhance shock therapy, especially when shock presents a more complex clinical picture than normal. However, their ability to improve clinical outcomes remains to be proven. It is the purpose of this review to describe the mechanism of action, dosage requirements, advantages and disadvantages, and specific indications and contraindications for the use of each of these catecholamines and vasopressors, as well as to elucidate the most important clinical trials that serve as the basis of contemporary shock therapy.

Lycium barbarum polysaccharides restore adverse structural remodelling and cardiac contractile dysfunction induced by overexpression of microRNA-1

MicroRNA‐1 (miR‐1) stands out as the most prominent microRNA (miRNA) in regulating cardiac function and has been perceived as a new potential therapeutic target. Lycium barbarum polysaccharides (LBPs) are major active constituents of the traditional Chinese medicine based on L. barbarum. The purpose of this study was to exploit the cardioprotective effect and molecular mechanism of LBPs underlying heart failure. We found that LBPs significantly reduced the expression of myocardial miR‐1. LBPs improved the abnormal ECG and indexes of cardiac functions in P‐V loop detection in transgenic (Tg) mice with miR‐1 overexpression. LBPs recovered morphological changes in sarcomeric assembly, intercalated disc and gap junction. LBPs reversed the reductions of CaM and cMLCK, the proteins targeted by miR‐1. Similar trends were also obtained in their downstream effectors including the phosphorylation of MLC2v and both total level and phosphorylation of CaMKII and cMyBP‐C. Collectively, LBPs restored adverse structural remodelling and improved cardiac contractile dysfunction induced by overexpression of miR‐1. One of the plausible mechanisms was that LBPs down‐regulated miR‐1 expression and consequently reversed miR‐1‐induced repression of target proteins relevant to myocardial contractibility. LBPs could serve as a new, at least a very useful adjunctive, candidate for prevention and therapy of heart failure.

Collagen-binding VEGF targeting the cardiac extracellular matrix promotes recovery in porcine chronic myocardial infarction

An effective therapy for chronic myocardial infarction (MI) has yet to be developed. Vascular endothelial growth factor (VEGF) promotes angiogenesis and improves cardiac function after MI. However, non-targeted delivery of VEGF decreases its therapeutic efficacy. In this study, for targeting the cardiac extracellular matrix, a collagen-binding domain (CBD) VEGF was used to bind specifically to the collagen-rich cardiac extracellular matrix. When intramyocardially injected into the peri-infarct region of a chronically infarcted porcine heart, CBD-VEGF attenuated the remodeling of the left ventricle with a decreased infarct size and promoted cardiomyocyte survival and angiogenesis 3 months after injection. In the 12-month trial, mature vessel networks and myocardium-like tissues were observed in the infarct region after CBD-VEGF injection. Also these beneficial effects might derive from CBD-VEGF significantly protecting cardiomyocytes from apoptosis and recruiting cardiac progenitor cells to the infarcted region. These results demonstrated that CBD-VEGF could be a promising therapeutic strategy for chronic MI.

Altered sarco(endo)plasmic reticulum calcium adenosine triphosphatase 2a content: Targets for heart failure therapy

Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is responsible for transporting cytosolic calcium into the sarcoplasmic reticulum and endoplasmic reticulum to maintain calcium homeostasis. Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is the dominant isoform expressed in cardiac tissue, which is regulated by endogenous protein inhibitors, post-translational modifications, hormones as well as microRNAs. Dysfunction of sarco(endo)plasmic reticulum calcium adenosine triphosphatase is associated with heart failure, which makes sarco(endo)plasmic reticulum calcium adenosine triphosphatase a promising target for heart failure therapy. This review summarizes current approaches to ameliorate sarco(endo)plasmic reticulum calcium adenosine triphosphatase function and focuses on phospholamban, an endogenous inhibitor of sarco(endo)plasmic reticulum calcium adenosine triphosphatase, pharmacological tools and gene therapies.

Effects of Levosimendan on Patients with Heart Failure Complicating Acute Coronary Syndrome: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The prognosis for patients with heart failure (HF), including cardiogenic shock (CS), complicating acute coronary syndrome (ACS) remains poor.

OBJECTIVE

This study aimed to review the relevant literature and evaluate whether levosimendan was associated with better clinical outcomes in these patients.

METHODS

We searched PubMed, EMBASE, and the Cochrane library databases for randomized controlled trials that investigated levosimendan compared with any control in patients with HF/CS complicating ACS.

RESULTS

A total of 1065 patients from nine trials were included in this study. Analysis showed that levosimendan significantly reduced total mortality and the incidence of worsening HF. In patients with HF-ACS, levosimendan was associated with reduced mortality. In patients with CS-ACS, no significant difference was observed between the two groups. Levosimendan contributed to significantly reduced mortality when compared with placebo, but no significant reduction was seen compared with dobutamine. Compared with controls, levosimendan decreased pulmonary capillary wedge pressure and systemic vascular resistance and increased cardiac index, with no significant difference observed between the groups in terms of heart rate. Levosimendan non-significantly increased the risk of hypotension but did not increase the risk of ischemic episodes, sinus tachycardia, atrial fibrillation, or ventricular arrhythmias.

CONCLUSION

Levosimendan appears to be a promising drug to reduce mortality and worsening HF in patients with HF/CS-ACS. It appears to provide hemodynamic benefit and was associated with an increased risk of hypotension.

Proteomic analysis of the protective effects of aqueous bark extract of Terminalia arjuna (Roxb.) on isoproterenol-induced cardiac hypertrophy in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aqueous bark extract of Terminalia arjuna (TA) has been in use as an ethnomedicine for cardiovascular ailments in the Indian subcontinent for centuries. Studies using hemodynamic, ROS scavenging and anti-inflammatory parameters in animal models have shown its anti-atherogenic, hypotensive, inotropic, anti-inflammatory effects. However, details analysis on its effects on established molecular and cell biological markers are a prerequisite for its wider acceptance to the medical community.

AIMS OF THE STUDY

To test the efficacy of TA extract in ameliorating cardiac hypertrophy induced by ISO in rats.

METHODS

Cardiac hypertrophy was induced by ISO (5mg/kg/day s.c. for 14 days) in rats and a standardized aqueous extract of TA stem bark was orally administered by gavage. Total RNA and protein were isolated from control, ISO, ISO plus TA and TA treated rat hearts and analyzed for the transcripts for the markers of hypertrophy, signaling kinases, transcription factors and total protein profile.

RESULTS

TA extract reversed the induction of fetal genes like β-myosin heavy chain, skeletal α-actin and brain natriuretic peptide in hypertrophic rat hearts. While ISO slightly increased the level of phospho-ERK, TA repressed it to about one third of the base line level. Survival kinase Akt, ER stress marker Grp78 and epigenetic regulator HDAC5 were augmented by ISO and TA restored them by various extents. ISO administration moderately increased the transcription factor NFκB binding activity, while coadministration of TA further increased it. AP-1 binding activity was largely unchanged by ISO treatment but it was upregulated when administered along with TA. MEF2D binding activity was increased by ISO and TA restored it to the baseline level. Global proteomic analysis revealed that TA treatment restored a subset of proteins up- and down-regulated in the hypertrophied hearts. Amongst those restored by TA were purinergic receptor X, myosin light chain 3, tropomyosin, and kininogen; suggesting a nodal role of TA in modulating cardiac function.

CONCLUSIONS

This study for the first time reveals that TA partially or completely restores the marker mRNAs, signaling kinases, transcription factors and total protein profile in rat heart, thereby demonstrating its efficacy in preventing ISO-induced cardiac hypertrophy.

MicroRNA and Heart Failure

Heart failure (HF) imposes significant economic and public health burdens upon modern society. It is known that disturbances in neurohormonal status play an important role in the pathogenesis of HF. Therapeutics that antagonize selected neurohormonal pathways, specifically the renin-angiotensin-aldosterone and sympathetic nervous systems, have significantly improved patient outcomes in HF. Nevertheless, mortality remains high with about 50% of HF patients dying within five years of diagnosis thus mandating ongoing efforts to improve HF management. The discovery of short noncoding microRNAs (miRNAs) and our increasing understanding of their functions, has presented potential therapeutic applications in complex diseases, including HF. Results from several genome-wide miRNA studies have identified miRNAs differentially expressed in HF cohorts suggesting their possible involvement in the pathogenesis of HF and their potential as both biomarkers and as therapeutic targets. Unravelling the functional relevance of miRNAs within pathogenic pathways is a major challenge in cardiovascular research. In this article, we provide an overview of the role of miRNAs in the cardiovascular system. We highlight several HF-related miRNAs reported from selected cohorts and review their putative roles in neurohormonal signaling.

Chronic heart failure: Ca(2+), catabolism, and catastrophic cell death

Robust successes have been achieved in recent years in conquering the acutely lethal manifestations of heart disease. Many patients who previously would have died now survive to enjoy happy and productive lives. Nevertheless, the devastating impact of heart disease continues unabated, as the spectrum of disease has evolved with new manifestations. In light of this ever-evolving challenge, insights that culminate in novel therapeutic targets are urgently needed. Here, we review fundamental mechanisms of heart failure, both with reduced (HFrEF) and preserved (HFpEF) ejection fraction. We discuss pathways that regulate cardiomyocyte remodeling and turnover, focusing on Ca(2+) signaling, autophagy, and apoptosis. In particular, we highlight recent insights pointing to novel connections among these events. We also explore mechanisms whereby potential therapeutic approaches targeting these processes may improve morbidity and mortality in the devastating syndrome of heart failure.

Emerging Therapies for Acute and Chronic Heart Failure

Although the period from 1953 to 2001 resulted in the approval of more than 30 medications currently used to treat heart failure (HF), few novel drugs have been approved in the last decade. However, the investigational pipeline for HF medications once again appears promising. In patients with chronic heart failure with reduced ejection fraction (HFrEF), ivabradine and valsartan/sucubitril (LCZ696) were recently approved by the US Food and Drug Administration. Both agents have been shown to reduce the risk of cardiovascular death and HF hospitalization. In the treatment of acute HF, serelaxin and ularitide are the farthest along in development. Both agents have demonstrated favorable effects on surrogate end points and preliminary data suggest a possible mortality benefit with serelaxin. Consequently, phase 3 trials are ongoing to evaluate the effect of serelaxin and ularitide on clinical outcomes. Given the poor history of recent investigational acute HF drugs that have advanced to phase 3/4 studies, enthusiasm for both serelaxin and ularitide must be tempered until these trials are completed.

Myocyte contractility can be maintained by storing cells with the myosin ATPase inhibitor 2,3 butanedione monoxime

Isolated intact myocytes can be used to investigate contractile mechanisms and to screen new therapeutic compounds. These experiments typically require euthanizing an animal and isolating fresh cells each day or analyzing cultured myocytes, which quickly lose their rod-shaped morphology. Recent data suggest that the viability of canine myocytes can be prolonged using low temperature and N-benzyl-p-toluene sulfonamide (an inhibitor of skeletal myosin ATPase). We performed similar studies in rat myocytes in order to test whether the cardiac myosin ATPase inhibitors 2,3-Butanedione monoxime (BDM) and blebbistatin help to maintain cell-level function over multiple days. Myocytes were isolated from rats and separated into batches that were stored at 4°C in a HEPES-buffered solution that contained 0.5 mmol L(-1) Ca(2+) and (1) no myosin ATPase inhibitors; (2) 10 mmol L(-1) BDM; or (3) 3 μmol L(-1) blebbistatin. Functional viability of myocytes was assessed up to 3 days after the isolation by measuring calcium transients and unloaded shortening profiles induced by electrical stimuli in inhibitor-free Tyrode's solution. Cells stored without myosin ATPase inhibitors had altered morphology (fewer rod-shaped cells, shorter diastolic sarcomere lengths, and membrane blebbing) and were not viable for contractile assays after 24 h. Cells stored in BDM maintained morphology and contractile function for 48 h. Storage in blebbistatin maintained cell morphology for 72 h but inhibited contractility. These data show that storing cells with myosin ATPase inhibitors can extend the viability of myocytes that will be used for functional assays. This may help to refine and reduce the use of animals in experiments.

Determinants of Utility Based on the EuroQol Five-Dimensional Questionnaire in Patients with Chronic Heart Failure and Their Change Over Time: Results from the Swedish Heart Failure Registry

BACKGROUND

There is limited information on drivers of utilities in patients with chronic heart failure (CHF).

OBJECTIVES

To analyze determinants of utility in CHF and drivers of change over 1 year in a large sample from clinical practice.

METHODS

We included 5334 patients from the Swedish Heart Failure Registry with EuroQol five-dimensional questionnaire information available following inpatient or outpatient care during 2008 to 2010; 3495 had 1-year follow-up data. Utilities based on Swedish and UK value sets were derived. We applied ordinary least squares (OLS) and two-part models for utility at inclusion and OLS regression for change over 1 year, all with robust standard errors. We assessed the predictive accuracy of both models using cross-validation.

RESULTS

Patients' mean age was 73 years, 65% were men, 19% had a left ventricular ejection fraction of 50% or more, 23% had 40% to 49%, 27% had 30% to 39%, and 31% had less than 30%. For both models and value sets, utility at inclusion was affected by sex, age, New York Heart Association class, ejection fraction, hemoglobin, blood pressure, lung disease, diabetes, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, nitrates, antiplatelets, and diuretics. The OLS model performed slightly better than did the two-part model on a population level and for capturing utility ranges. Change in utility over 1 year was influenced by age, sex, and (measured at inclusion) disease duration, New York Heart Association class, blood pressure, ischemic heart disease, lung disease, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and antiplatelets.

CONCLUSIONS

Utilities in CHF and their change over time are influenced by diverse demographic and clinical factors. Our findings can be used to target clinical interventions and for economic evaluations of new therapies.

Abnormalities of capillary microarchitecture in a rat model of coronary ischemic congestive heart failure

The aim of the present study is to explore the role of capillary disorder in coronary ischemic congestive heart failure (CHF). CHF was induced in rats by aortic banding plus ischemia-reperfusion followed by aortic debanding. Coronary arteries were perfused with plastic polymer containing fluorescent dye. Multiple fluorescent images of casted heart sections and scanning electric microscope of coronary vessels were obtained to characterize changes in the heart. Cardiac function was assessed by echocardiography and in vivo hemodynamics. Stenosis was found in all levels of the coronary arteries in CHF. Coronary vasculature volume and capillary density in remote myocardium were significantly increased in CHF compared with control. This occurred largely in microvessels with a diameter of ≤3 μm. Capillaries in CHF had a tortuous structure, while normal capillaries were linear. Capillaries in CHF had inconsistent diameters, with assortments of narrowed and bulged segments. Their surfaces appeared rough, potentially indicating endothelial dysfunction in CHF. Segments of main capillaries between bifurcations were significantly shorter in length in CHF than in control. Transiently increasing preload by injecting 50 μl of 30% NaCl demonstrated that the CHF heart had lower functional reserve; this may be associated with congestion in coronary microcirculation. Ischemic coronary vascular disorder is not limited to the main coronary arteries, as it occurs in arterioles and capillaries. Capillary disorder in CHF included stenosis, deformed structure, proliferation, and roughened surfaces. This disorder in the coronary artery architecture may contribute to the reduction in myocyte contractility in the setting of heart failure.

The regulation of sarco(endo)plasmic reticulum calcium-ATPases (SERCA)

The sarco(endo)plasmic reticulum calcium ATPase (SERCA) is responsible for transporting calcium (Ca(2+)) from the cytosol into the lumen of the sarcoplasmic reticulum (SR) following muscular contraction. The Ca(2+) sequestering activity of SERCA facilitates muscular relaxation in both cardiac and skeletal muscle. There are more than 10 distinct isoforms of SERCA expressed in different tissues. SERCA2a is the primary isoform expressed in cardiac tissue, whereas SERCA1a is the predominant isoform expressed in fast-twitch skeletal muscle. The Ca(2+) sequestering activity of SERCA is regulated at the level of protein content and is further modified by the endogenous proteins phospholamban (PLN) and sarcolipin (SLN). Additionally, several novel mechanisms, including post-translational modifications and microRNAs (miRNAs) are emerging as integral regulators of Ca(2+) transport activity. These regulatory mechanisms are clinically relevant, as dysregulated SERCA function has been implicated in the pathology of several disease states, including heart failure. Currently, several clinical trials are underway that utilize novel therapeutic approaches to restore SERCA2a activity in humans. The purpose of this review is to examine the regulatory mechanisms of the SERCA pump, with a particular emphasis on the influence of exercise in preventing the pathological conditions associated with impaired SERCA function.

Pulmonary arterial capacitance in patients with heart failure and reactive pulmonary hypertension

AIMS

Reactive pulmonary hypertension (PH) is a severe form of PH secondary to left-sided heart failure (HF). Given the structural and functional abnormalities in the pulmonary vasculature that occur in reactive PH, we hypothesized that pulmonary artery capacitance (PAC) may be profoundly affected, with implications for clinical outcome.

METHODS AND RESULTS

We studied 393 HF patients of whom 124 (32%) were classified as having passive PH and 140 (36%) as having reactive PH, and 91 patients with pulmonary arterial hypertension (PAH). Mean PAC was highest in patients without PH (4.5 ± 2.1 mL/mmHg), followed by the passive PH group (2.8 ± 1.4 mL/mmHg) and was lowest in those with reactive PH (1.8 ± 0.7 mL/mmHg) (P = 0.0001). PAC and pulmonary vascular resistance (PVR) fitted well to a hyperbolic inverse relationship (PAC = 0.25/PVR, R(2)  = 0.70), with reactive PH patients dispersed almost predominantly on the flat part of the curve where a reduction in PVR is associated with a small improvement in PAC. Elevated PCWP was associated with a significant lowering of PAC for any PVR (P = 0.036). During a median follow-up of 31 months, both reactive PH [hazard ratio (HR) 2.59, 95% confidence interval (CI) 1.14-4.46, P = 0.02] and reduced PAC (HR 0.72 per 1 mL/mmHg increase, 95% CI 0.59-0.88, P = 0.001) were independent predictors of mortality.

CONCLUSIONS

The development of reactive PH is associated with a marked reduction in PAC. PAC is a strong independent haemodynamic marker of mortality in HF and may contribute to the increased mortality associated with reactive PH.

Medication management of chronic heart failure in older adults

Heart failure (HF) is a common problem in older adults. Individuals aged 65 years or older are at a higher risk for developing HF, especially diastolic HF or HF with preserved ejection fraction (HFpEF). HF can be seen in up to 20 % of adults aged 85 years or older. In contrast to middle-aged (40-64 years) HF patients, multiple cardiac, non-cardiac and geriatric syndrome co-morbidities are seen in elderly HF patients. Additionally, age-related changes in pharmacokinetics and pharmacodynamics influence medication therapy. Hence, the management of older patients with HF is challenging and treatment should be modified in the light of the above-mentioned conditions. This article discusses the current evidence for medication management in both systolic HF or HF with reduced ejection fraction (HFrEF) and HFpEF, noting, however, the limited data for HFpEF and HFrEF in those 80 years of age or older. The objective of this article is to discuss evidence-based and outcomes-driven pharmacologic management strategies for chronic HF in the older adults for whom functional and other patient-centered outcomes might be more than or as important as clinical outcomes. Optimal management would be expected to help to reduce illness burden, reduce mortality and hospitalizations, and improve function and quality of life.

Dynamic changes in myocardial matrix and relevance to disease: translational perspectives

The cardiac extracellular matrix (ECM) provides the architectural scaffold to support efficient contraction and relaxation of cardiomyocytes. The elegant design of the ECM facilitates optimal force transduction, electric transmission, intercellular communication, and metabolic exchange within the myocardial microenvironment. In the setting of increased wall stress, injury, or disease, the ECM can undergo a series of dynamic changes that lead to favorable chamber remodeling and functional adaptation. Over time, sustained matrix remodeling can impair diastolic and systolic function caused by excess deposition of interstitial fibrous tissue. These pathological alterations in ECM structure/function are considered central to the evolution of adverse cardiac remodeling and the development of heart failure. This review discusses the complex dynamics of the cardiac ECM in the setting of myocardial infarction, pressure overload, and volume overload. We also summarize the current status of ECM biomarkers that may have clinical value in prognosticating cardiac disease progression in patients. Finally, we discuss the most current status of drugs under evaluation for use in cardiac fibrosis.

Concordant changes of plasma and kidney microRNA in the early stages of acute kidney injury: time course in a mouse model of bilateral renal ischemia-reperfusion

BACKGROUND

Acute kidney injury (AKI) is a syndrome characterized by the rapid loss of the kidney excretory function and is strongly associated with increased early and long-term patient morbidity and mortality. Early diagnosis of AKI is challenging; therefore we profiled plasma microRNA in an effort to identify potential diagnostic circulating markers of renal failure. The goal of the present study was to investigate the dynamic relationship of circulating and renal microRNA profiles within the first 24 hours after bilateral ischemia-reperfusion kidney injury in mice.

METHODOLOGY/PRINCIPAL FINDINGS

Bilateral renal ischemia was induced in C57Bl/6 mice (n = 10 per group) by clamping the renal pedicle for 27 min. Ischemia-reperfusion caused highly reproducible, progressive, concordant elevation of miR-714, miR-1188, miR-1897-3p, miR-877*, and miR-1224 in plasma and kidneys at 3, 6 and 24 hours after acute kidney injury compared to the sham-operated mice (n = 5). These dynamics correlated with histologic findings of kidney injury and with a conventional plasma marker of renal dysfunction (creatinine). Pathway analysis revealed close association between miR-1897-3p and Nucks1 gene expression, which putative downstream targets include genes linked to renal injury, inflammation and apoptosis.

CONCLUSIONS/SIGNIFICANCE

Systematic profiling of renal and plasma microRNAs in the early stages of experimental AKI provides the first step in advancing circulating microRNAs to the level of promising novel biomarkers.

Investigation of cenderitide controlled release platforms for potential local treatment of cardiovascular pathology

In this work, we focused on the development and investigation of controlled release matrices for a novel cardiotherapeutic peptide, cenderitide (CD-NP) that has shown to be useful for control of ventricular remodeling. To circumvent the hydrophilicity disparity between CD-NP and hydrophobic polymer matrix, a cosolvent system (water/dichloromethane) was selected for investigation. The effect of emulsification conditions, addition of poly(ethylene glycol) (PEG) and its copolymer on the release mechanism and profile were investigated. To verify the retention of bioactivity of entrapped CD-NP in different formulations, the generation of 3',5' cyclic guanosine monophospate (cGMP) and the inhibition of human cardiac fibroblast (HCF) were evaluated. The results showed that neat poly(ε-caprolactone) matrices carried out via two distinct emulsification conditions had either an unacceptably high burst or incomplete release of CD-NP; and the addition of PEG and its copolymer obtained intermediate profiles. Our confocal laser scanning microscopy and surface morphological investigations showed that the copolymer excipient was superior in playing stabilizer role by colocalizing and redistributing peptide throughout the matrix, making the release less sensitive to emulsification conditions. Furthermore, the released CD-NP is able to generate the cGMP and inhibit the HCF proliferation. Our investigations showed that CD-NP-loaded platforms can be a feasible option to provide sustained antifibrotic moderation of fibrotic scar formation and be potentially used to alleviate the adverse effects of cardiac remodeling.

Regeneration of chronic myocardial infarction by injectable hydrogels containing stem cell homing factor SDF-1 and angiogenic peptide Ac-SDKP

Regeneration of chronic myocardial infarction (CMI) is one of the challenging issues due to its limited regeneration activity compared to acute or sub-acute stage. In this study, we examined whether combination of stem cell homing factor (SDF-1) and angiogenic peptides (Ac-SDKP) injected with biomimetic hydrogels promote regeneration of cardiac function in a CMI model. We evaluated the regeneration of chronically infarcted myocardium using injectable biomimetic hydrogels containing two therapeutic factors; stromal-derived factor-1 (SDF-1) and Ac-SDKP for stem cell homing and angiogenesis, respectively. Injection of the two therapeutic factors into the infarct region of the left ventricle showed that the biomimetic hydrogels containing two therapeutic factor exhibited significantly improved left ventricle function, increased angiogenesis, decreased infarct size and greatest wall thickness within the infarct region at 4 weeks post-treatment. From these results, it is clear that hydrogels containing two therapeutic factors showed synergistic effects on regeneration in the chronic heart failure model. In conclusion, these results suggest that combination of stem cell homing factor with angiogenic peptides recruit stem cells to the microenvironments, increase the expression of angiogenic genes, enhance the matured vessel formation and improve the cardiac function in chronic MI.

Temperature and transmural region influence functional measurements in unloaded left ventricular cardiomyocytes

Intact cardiomyocytes are increasingly being used to investigate the molecular mechanisms of contraction and to screen new therapeutic compounds. The function of the cardiomyocytes is often measured from the calcium transients and sarcomere length profiles. We studied the role of experimental temperature and transmural region on indices of function in freshly isolated, unloaded cardiomyocytes. Intact cardiomyocytes were isolated from the subendocardium, midmyocardium, and subepicardium of 3-month-old Sprague-Dawley rats. Myocytes from each region were studied at 25°C, 31°C, and 37°C. Cytosolic calcium transients were measured using Fura-2 fluorescence, whereas sarcomere length shortening and relengthening profiles were measured using high-speed video capture. For both the calcium transients and sarcomere length profiles, the time to peak and the time to half relaxation decreased significantly with increasing temperature. Increasing temperature also raised the minimum and maximum calcium levels of all cells. Of note, there was a reduced coefficient of variation (standard deviation divided by the mean) at higher temperatures for calcium fluorescence amplitudes, time to peak calcium, and rates of sarcomeric shortening and relengthening. The amplitudes and minimum of the calcium transients were significantly dependent on transmural region, and several sarcomere length parameters exhibited statistical interactions between temperature and transmural region. Together, these results show that biological variability can be reduced by performing experiments at 37°C rather than at room temperature, and by isolating cells from a specific transmural region. Adopting these procedures will improve the statistical power of subsequent analyses and increase the efficiency of future experiments.

Novel quercetin derivatives in treatment of peroxynitrite-oxidized SERCA1

Sarco/endoplasmic reticulum calcium ATP-ase (SERCA) is regulated by low concentrations of peroxynitrite and inhibited by high levels, as indicated in human diseases. We studied quercetin (Q) and its novel derivatives monochloropivaloylquercetin (MPQ) and chloronaphthoquinonequercetin (CHQ) as agents with expected preventive properties against peroxynitrite-induced SERCA impairment. Q and MPQ protected the SERCA1 against peroxynitrite induced activity decrease, while CHQ potentiated the inhibitory effect of peroxynitrite. Quercetin derivatives were found to be weaker antioxidants compared with Q, as indicated by their ability to scavenge peroxynitrite and prevent of SERCA1 carbonylation, both decreasing in the order (Q > MPQ > CHQ). Quantum-chemical values of theoretical parameter E HOMO also indicated lower antioxidant capacities for MPQ and CHQ. Prooxidant properties estimated by calculations of frontier molecular orbitals (E LUMO) correlated with experimentally determined SH-group decrease induced by the compounds studied. Both methods showed a decrease of prooxidant properties as follows: CHQ > MPQ > Q. In addition, experimentally measured half-wave potentials indicated stronger prooxidant properties of quercetin derivatives as compared to Q. More expressive alterations of conformation in the transmembrane region of SERCA1 induced by quercetin derivatives, as compared with Q, may at least partially correlate with their higher lipophilicities. The protective effects of Q and MPQ on different isoforms of SERCA activity may be useful in prevention and treatment of inflammation or muscle diseases. The inhibitory effect of CHQ on SERCA isoforms may be beneficial in therapeutic approaches aimed at anti-tumor treatment.

Cenderitide-eluting film for potential cardiac patch applications

Cenderitide, also known as CD-NP, is a designer peptide developed by combining native mammalian c-type natriuretic peptide (CNP) and the C-terminus isolated from the dendroapis natriuretic peptide (DNP) of the venom from the green mamba. In early studies, intravenous and subcutaneous infusion of cenderitide was reported to reduce left ventricular (LV) mass and ameliorate cardiac remodelling. In this work, biodegradable polymeric films encapsulating CD-NP were developed and were investigated for their in vitro release and degradation characteristics. Subsequently, the bioactivity of released peptide and its effects on human cardiac fibroblast (HCF) were explored. We achieved sustained release from three films with low, intermediate and high release profiles for 30 days. Moreover, the bioactivity of released peptide was verified from the elevated production of cyclic guanosine monophospate (cGMP). The CD-NP released from films was able to inhibit the proliferation of hypertrophic HCF as well as suppress DNA synthesis in HCF. Furthermore, the sustained delivery from films showed comparable or superior suppressive actions on hypertrophic HCF compared to daily infusion of CD-NP. The results suggest that these films could be used to inhibit fibrosis and reduce cardiac remodelling via local delivery as cardiac patches.

Clinical effects of Xinmailong therapy in patients with chronic heart failure

In the last 100 years, intensive studies have been done on the identification of the systematic approaches to find the cure for the chronic heart failure, however the mystery remains unresolved due to its complicated pathogenesis and ineffective early diagnosis. The present investigation was aimed to evaluate the potential effects of the traditional chinese medicine, Xinmailong, on the chronic heart failure (CHF) patients as compared to the standard western medical treatment available so far. In our study, we selected two groups of voluntary CHF patients at the Xiangya Hospital, which were allowed to administrate Xinmailong or standard treatments, respectively. Another group of voluntary healthy individuals were recruited as the control group. The treatment effectiveness was measured by five symptomatic factors, i.e. angiotensin II (Ang_II), high sensitivity C-reactive protein (hs_CRP), Left Ventricular End Systolic Volume Index (LVESVI), left ventricular ejection fraction (LVEF) and pro-B-type natriuretic peptide (NT_proBNP), between the control group and the CHF patients at different stages of drug administration and in different treatment groups. The timeline for the full dose administration was set to 15 days and five measurements as indicated above were taken on every 0, 7th and 15th day of the drug administration respectively. In the conducted study, similar symptomatic measurements were observed on day 0 in both treatment groups, and slight improvements were observed on 7th day. It was observed that after a full course of drug administration for 15 days, both of the treatment groups achieved statistically significant improvements in all the five measures, but Xinmailong was found to be more (almost double) statistically significant as compared with the available drug treatments for chronic heart failure.

A detailed physiologically based model to simulate the pharmacokinetics and hormonal pharmacodynamics of enalapril on the circulating endocrine Renin-Angiotensin-aldosterone system

The renin-angiotensin-aldosterone system (RAAS) plays a key role in the pathogenesis of cardiovascular disorders including hypertension and is one of the most important targets for drugs. A whole body physiologically based pharmacokinetic (wb PBPK) model integrating this hormone circulation system and its inhibition can be used to explore the influence of drugs that interfere with this system, and thus to improve the understanding of interactions between drugs and the target system. In this study, we describe the development of a mechanistic RAAS model and exemplify drug action by a simulation of enalapril administration. Enalapril and its metabolite enalaprilat are potent inhibitors of the angiotensin-converting-enzyme (ACE). To this end, a coupled dynamic parent-metabolite PBPK model was developed and linked with the RAAS model that consists of seven coupled PBPK models for aldosterone, ACE, angiotensin 1, angiotensin 2, angiotensin 2 receptor type 1, renin, and prorenin. The results indicate that the model represents the interactions in the RAAS in response to the pharmacokinetics (PK) and pharmacodynamics (PD) of enalapril and enalaprilat in an accurate manner. The full set of RAAS-hormone profiles and interactions are consistently described at pre- and post-administration steady state as well as during their dynamic transition and show a good agreement with literature data. The model allows a simultaneous representation of the parent-metabolite conversion to the active form as well as the effect of the drug on the hormone levels, offering a detailed mechanistic insight into the hormone cascade and its inhibition. This model constitutes a first major step to establish a PBPK-PD-model including the PK and the mode of action (MoA) of a drug acting on a dynamic RAAS that can be further used to link to clinical endpoints such as blood pressure.

Heart failure

Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches.

Hemodynamic determinants of dyspnea improvement in acute decompensated heart failure

BACKGROUND

Dyspnea relief constitutes a major treatment goal and a key measure of treatment efficacy in decompensated heart failure. However, there are no data with regard to the relationship between hemodynamic measurements during treatment and dyspnea improvement.

METHODS AND RESULTS

We studied 233 patients assigned to right heart catheterization in the Vasodilation in the Management of Acute Congestive Heart Failure trial. Dyspnea (assessed using a 7-point Likert scale) and hemodynamic parameters were measured simultaneously at 15 and 30 minutes and 1, 2, 3, 6, and 24 hours. Dyspnea relief was defined as moderate or marked improvement. There was a time-dependent association between the reductions in pulmonary capillary wedge pressure (PCWP; 25.4, 24.6, 24.0, 23.5, 23.4, 21.5, and 19.9 mm Hg) and the percentage of patients achieving dyspnea relief (17.7%, 24.6%, 32.2%, 36.2%, 37.8%, 47.4%, and 66.1%, in the respective time points). Multivariable logistic generalized estimating equations modeling demonstrated that reductions of both PCWP and mean pulmonary artery pressure were independently associated with dyspnea relief. Compared with the highest PCWP quartile, the adjusted odds ratios for dyspnea relief were 0.92 (95% confidence interval [CI], 0.67-1.29), 1.07 (95% CI, 0.75-1.55), and 1.80 (95% CI, 1.22-2.65) in the third, second, and first PCWP quartiles, respectively (P(trend)=0.003). Compared with the highest mean pulmonary artery pressure quartile, the adjusted odds ratios for dyspnea relief were 2.0 (95% CI, 1.41-2.82), 2.23 (95% CI, 1.52-3.27), and 2.98 (95% CI, 1.91-4.66) in the third, second, and first mean pulmonary artery pressure quartiles, respectively (P(trend)<0.0001).

CONCLUSIONS

A clinically significant improvement in dyspnea is associated with a reduction in both PCWP and mean pulmonary artery pressure.