Cardiometabolic HFpEF: mechanisms and therapies

Heart failure with preserved ejection fraction (HFpEF) accounts for at least half of all patients with heart failure (HF) and is projected to be the most common form of HF in the near feature. HFpEF, characterized by high morbidity and mortality, poses an enormous medical and societal burden and lacks evidence-based therapies. Hence, HFpEF has been recognized as the greatest unmet need in cardiovascular medicine. HFpEF is a heterogenous syndrome presenting as several different clinical phenotypes. Among these, metabolic alteration-driven HFpEF - i.e. cardiometabolic HFpEF - is emerging around the globe as the most prevalent form of HFpEF. Pathophysiological mechanisms of cardiometabolic HFpEF are still incompletely understood. However, recent advances in the preclinical modeling of the syndrome, coupled with better definition of its clinical presentations and analysis of human HFpEF myocardial specimens, have unveiled metabolic disturbances and inflammatory burden as 2 key drivers of HFpEF pathophysiology. Here, we summarize evidence in support of a cardiometabolic phenotype of HFpEF and discuss the pivotal biological mechanisms underlying this syndrome in the hope of informing more efficacious therapeutic approaches in the future

Heart failure with preserved ejection fraction in humans and mice: embracing clinical complexity in mouse models

Heart failure (HF) with preserved ejection fraction (HFpEF) is a multifactorial disease accounting for a large and increasing proportion of all clinical HF presentations. As a clinical syndrome, HFpEF is characterized by typical signs and symptoms of HF, a distinct cardiac phenotype and raised natriuretic peptides. Non-cardiac comorbidities frequently co-exist and contribute to the pathophysiology of HFpEF. To date, no therapy has proven to improve outcomes in HFpEF, with drug development hampered, at least partly, by lack of consensus on appropriate standards for pre-clinical HFpEF models. Recently, two clinical algorithms (HFA-PEFF and H(2)FPEF scores) have been developed to improve and standardize the diagnosis of HFpEF. In this review, we evaluate the translational utility of HFpEF mouse models in the context of these HFpEF scores. We systematically recorded evidence of symptoms and signs of HF or clinical HFpEF features and included several cardiac and extra-cardiac parameters as well as age and sex for each HFpEF mouse model. We found that most of the pre-clinical HFpEF models do not meet the HFpEF clinical criteria, although some multifactorial models resemble human HFpEF to a reasonable extent. We therefore conclude that to optimize the translational value of mouse models to human HFpEF, a novel approach for the development of pre-clinical HFpEF models is needed, taking into account the complex HFpEF pathophysiology in humans

High-resolution transthoracic echocardiography accurately detects pulmonary arterial pressure and decreased right ventricular contractility in a mouse model of pulmonary fibrosis and secondary pulmonary hypertension

BACKGROUND: To date, assessment of right ventricular (RV) function in mice has relied extensively on invasive measurements. Echocardiographic advances have allowed adaptation of measures used in humans for serial, noninvasive RV functional assessment in mice. We evaluated the diagnostic performance of tricuspid annular plane systolic excursion (TAPSE), RV peak systolic myocardial velocity (s'), RV myocardial performance index (MPI), and RV fractional area change (FAC) in a mouse model of pulmonary hypertension. METHODS AND RESULTS: Echocardiography was performed on mice at baseline and 3 weeks after induction of pulmonary hypertension using inhaled bleomycin or saline, including adapted measures of TAPSE, s', MPI, and FAC. RV systolic pressure was measured by invasive catheterization, and RV contractility was measured as the peak slope of the RV systolic pressure recording (maximum change pressure/change time). Postmortem morphological assessment of RV hypertrophy was performed. RV systolic pressure was elevated and maximum change pressure/change time was reduced in bleomycin versus control (n=8; P=0.002). Compared with controls, bleomycin mice had reduced TAPSE (0.79±0.05 versus 1.06±0.04 mm; P=0.003), s' (21.3±1.2 versus 29.2±1.3 mm/s; P<0.001), and FAC (20.3±0.7% versus 31.0±1.3%; P<0.001), whereas MPI was increased (0.51±0.03 versus 0.37±0.01; P=0.006). All measures correlated with RV systolic pressure and maximum change pressure/change time. Intraobserver and interobserver variability were minimal. Receiver operating characteristic curves demonstrated that TAPSE (<0.84 mm), s'(<23.3 mm/s), MPI (0.42), and FAC (<23.3%) identified maximum change pressure/change time ≤2100 mm Hg/s with high accuracy. CONSLUSIONS: TAPSE, s', MPI, and FAC are measurable consistently using high-resolution echocardiography in mice, and are sensitive and specific measures of pulmonary pressure and RV function. This validation opens the opportunity for serial noninvasive measures in mouse models of pulmonary hypertension, enhancing the statistical power of preclinical studies of novel therapeutics

Identification of the ligands of protein interaction domains through a functional approach

The identification of protein-protein interaction networks has often given important information about the functions of specific proteins and on the cross-talk among metabolic and regulatory pathways. The availability of entire genome sequences has rendered feasible the systematic screening of collections of proteins, often of unknown function, aimed to find the cognate ligands. Once identified by genetic and/or biochemical approaches, the interaction between two proteins should be validated in the physiologic environment. Herein we describe an experimental strategy to screen collections of protein-protein interaction domains to find and validate candidate interactors. The approach is based on the assumption that the overexpression in cultured cells of protein-protein interaction domains, isolated from the context of the whole protein, could titrate the endogenous ligand and, in turn, exert a dominant negative effect. The identification of the ligand could provide us with a tool to check the relevance of the interaction because the contemporary overexpression of the isolated domain and of its ligand could rescue the dominant negative phenotype. We explored this approach by analyzing the possible dominant negative effects on the cell cycle progression of a collection of phosphotyrosine binding (PTB) domains of human proteins. Of 47 PTB domains, we found that the overexpression of 10 of them significantly interfered with the cell cycle progression of NIH3T3 cells. Four of them were used as baits to identify the cognate interactors. Among these proteins, CARM1, interacting with the PTB domain of RabGAP1, and EF1alpha, interacting with RGS12, were able to rescue the block of the cell cycle induced by the isolated PTB domain of the partner protein, thus confirming in vivo the relevance of the interaction. These results suggest that the described approach can be used for the systematic screening of the ligands of various protein-protein interaction domains also by using different biological assays

Total occlusion of the abdominal aorta in a patient with renal failure and refractory hypertension: a case report

Total occlusion of the abdominal aorta is unusual, and potentially catastrophic. It occurs in patients with advanced atherosclerotic occlusive disease, and can cause severe ischemic manifestations, depending on the site of obstruction. Prompt and appropriate diagnostic and therapeutic approaches are important whenever this condition is suspected, in order to avoid a fatal outcome. The development of a complex network of collaterals may prevent the manifestation of acute ischemic phenomena, and cause a delay in diagnosis and treatment. Here we report the clinical case of a 59-year-old man who was referred to our Department for evaluation of renal failure and refractory hypertension. Ultrasonography and 99mTc-DTPA scintigraphy showed a shrunken, non-functioning left kidney, while CT angiography and aortography showed the complete occlusion of the aorta from below the right renal artery down to the bifurcation of both common iliac arteries, with a critical stenosis of the origin of the right renal artery, an occlusion of the left renal artery as well as of the origin of the inferior mesenteric artery. The patient was referred to the surgery department for aorto-bifemoral bypass surgery and re-implantation of the right renal artery

Effects of a new combination of nutraceuticals with Morus alba on lipid profile, insulin sensitivity and endotelial function in dyslipidemic subjects. A cross-over, randomized, double-blind trial

INTRODUCTION: Nutraceuticals (NUT) are forms of compounds with biological activity commonly used to improve health in dosage largely exceeding those obtainable in food. AIM: We compared, in a double blind randomized cross-over trial, the effects of two NUT combinations on the control of glico-lipidic metabolism in patients with hypercholesterolemia not on statins. METHODS: At study start patients were given dietary counseling and received placebo for 2 weeks. After this run-in period, patients were randomized: (1) Combination A [Policosanol, Red yeast rice (Monakolin K 3 mg), Berberine 500 mg, Astaxantine, Folic Acid and Coenzyme Q10] for 4 weeks followed by 4 weeks of Combination B [Red yeast rice (Monakolin K 3.3 mg), Berberine 531.25 mg and leaf extract of Morus alba]; (2) Combination B for 4 weeks followed by 4 weeks of Combination A. RESULTS: Combination B reduced LDL cholesterol below 130 mg/dl in 56.5 % of the patients, and Cambination A only in 21.7 % of them (p ≤ 0.027). Both treatments reduced plasma levels of triglycerides, total and LDL cholesterol and increased HDL cholesterol (all p < 0.03). Total and LDL cholesterol reduction was more pronounced in patients taking Combination B (p < 0.005). Combination B reduced also glycated hemoglobin, fasting glucose and insulin plasma levels as well as HOMA index (p < 0.005). CONCLUSIONS: An increased content of Berberin and Monacolin K and the addition of Morus alba extract improves the effect on plasma cholesterol and on glucose metabolism of the NUT Combination. These effects may allow the speculation of a more marked improvement in cardiovascular prognosis

The DWORF micropeptide enhances contractility and prevents heart failure in a mouse model of dilated cardiomyopathy

Calcium (Ca(2+)) dysregulation is a hallmark of heart failure and is characterized by impaired Ca(2+) sequestration into the sarcoplasmic reticulum (SR) by the SR-Ca(2+)-ATPase (SERCA). We recently discovered a micropeptide named DWORF (DWarf Open Reading Frame) that enhances SERCA activity by displacing phospholamban (PLN), a potent SERCA inhibitor. Here we show that DWORF has a higher apparent binding affinity for SERCA than PLN and that DWORF overexpression mitigates the contractile dysfunction associated with PLN overexpression, substantiating its role as a potent activator of SERCA. Additionally, using a well-characterized mouse model of dilated cardiomyopathy (DCM) due to genetic deletion of the muscle-specific LIM domain protein (MLP), we show that DWORF overexpression restores cardiac function and prevents the pathological remodeling and Ca(2+) dysregulation classically exhibited by MLP knockout mice. Our results establish DWORF as a potent activator of SERCA within the heart and as an attractive candidate for a heart failure therapeutic

AngioJet® rheolytic thrombectomy for acute superficial femoral artery stent or femoropopliteal by-pass thrombosis

Thrombosis of superficial femoral artery (SFA) nitinol stents or polytetrafluoroethylene (PTFE) femoropopliteal bypass grafts after discontinuation of antiplatelet therapy is an emergent clinical challenge of acute limb ischemia (ALI), requiring immediate percutaneous intervention. Currently, there is no evidence-based approach for the management of such complications. We describe the cases of two patients presenting with ALI due to nitinol stent thrombosis after discontinuation of antiplatelet therapy and the case of a patient presenting with ALI due to PTFE femoropopliteal graft thrombosis in which limb salvage was obtained by AngioJet rheolytic thrombectomy and re-stenting. In both cases, the thrombus was successfully removed using the Possis AngioJet mechanical thrombectomy catheter and percutaneous transluminal angioplasty (PTA) was performed to recanalize two femoropopliteal nitinol stents and a femoropopliteal PTFE graft. In both cases, optimal angiographic result was obtained. To the best of our knowledge, these are the first three cases reporting the use of the AngioJet rheolytic thrombectomy in ALI due to stent or graft thrombosis. Taken together, these cases suggest that AngioJet rheolytic thrombectomy might represent a novel effective strategy in the percutaneous treatment of stent or graft thrombosis determining ALI

Mitochondrial a kinase anchor proteins in cardiovascular health and disease: a review article on behalf of the Working Group on Cellular and Molecular Biology of the Heart of the Italian Society of Cardiology

Second messenger cyclic adenosine monophosphate (cAMP) has been found to regulate multiple mitochondrial functions, including respiration, dynamics, reactive oxygen species production, cell survival and death through the activation of cAMP-dependent protein kinase A (PKA) and other effectors. Several members of the large family of A kinase anchor proteins (AKAPs) have been previously shown to locally amplify cAMP/PKA signaling to mitochondria, promoting the assembly of signalosomes, regulating multiple cardiac functions under both physiological and pathological conditions. In this review, we will discuss roles and regulation of major mitochondria-targeted AKAPs, along with opportunities and challenges to modulate their functions for translational purposes in the cardiovascular system

Genetic deletion of uncoupling protein 3 exaggerates apoptotic cell death in the ischemic heart leading to heart failure

BACKGROUND: Uncoupling protein 3 (ucp3) is a member of the mitochondrial anion carrier superfamily of proteins uncoupling mitochondrial respiration. In this study, we investigated the effects of ucp3 genetic deletion on mitochondrial function and cell survival under low oxygen conditions in vitro and in vivo. METHODS AND RESULTS: To test the effects of ucp3 deletion in vitro, murine embryonic fibroblasts and adult cardiomyocytes were isolated from wild-type (WT, n=67) and ucp3 knockout mice (ucp3(-/-), n=70). To test the effects of ucp3 genetic deletion in vivo, myocardial infarction (MI) was induced by permanent coronary artery ligation in WT and ucp3(-/-) mice. Compared with WT, ucp3(-/-) murine embryonic fibroblasts and cardiomyocytes exhibited mitochondrial dysfunction and increased mitochondrial reactive oxygen species generation and apoptotic cell death under hypoxic conditions in vitro (terminal deoxynucleotidyl transferase-dUTP nick end labeling-positive nuclei: WT hypoxia, 70.3 ± 1.2%; ucp3(-/-) hypoxia, 85.3 ± 0.9%; P<0.05). After MI, despite similar areas at risk in the 2 groups, ucp3(-/-) hearts demonstrated a significantly larger infarct size compared with WT (infarct area/area at risk: WT, 48.2 ± 3.7%; ucp3(-/-), 65.0 ± 2.9%; P<0.05). Eight weeks after MI, cardiac function was significantly decreased in ucp3(-/-) mice compared with WT (fractional shortening: WT MI, 42.7 ± 3.1%; ucp3(-/-) MI, 24.4 ± 2.9; P<0.05), and this was associated with heightened apoptotic cell death (terminal deoxynucleotidyl transferase-dUTP nick end labeling-positive nuclei: WT MI, 0.7 ± 0.04%; ucp3(-/-) MI, 1.1 ± 0.09%, P<0.05). CONCLUSIONS: Our data indicate that ucp3 levels regulate reactive oxygen species levels and cell survival during hypoxia, modulating infarct size in the ischemic heart