Dysregulation of proangiogeneic factors in pressure-overload left-ventricular hypertrophy results in inadequate capillary growth

Heart Failure With Preserved Ejection Fraction: Will Cardiac Magnetic Imaging Impact on Diagnosis, Treatment, and Outcomes?: Explaining the Need for Advanced Imaging to Clinical Stakeholders

Clinicians frequently equate symptoms of volume overload to heart failure (HF) but such generalization may preclude diagnostic or etiologic precision essential to optimizing outcomes. HF itself must be specified as the disparate types of cardiac pathology have been traditionally surmised by examination of left ventricular (LV) ejection fraction (EF) as either HF with preserved LVEF (HFpEF-LVEF >50%) or reduced LVEF of (HFrEF-LVEF <40%). More recent data support a third, potentially transitional HF subtype, but therapy, assessment, and prognosis have been historically dictated within the corresponding LV metrics determined by echocardiography. The present effort asks whether this historically dominant role of echocardiography is now shifting slightly, becoming instead a shared if not complimentary test. Will there be a gradual increasing profile for cardiac magnetic resonance as the attempt to further refine our understanding, diagnostic accuracy, and outcomes for HFpEF is attempted?

Roxadustat reduces left ventricular mass index compared to rHuEPO in haemodialysis patients in a randomized controlled trial

BACKGROUND

Left ventricular hypertrophy (LVH) is highly prevalent in haemodialysis (HD) patients and is associated with an increased risk of death. Roxadustat and recombinant human erythropoietin (rHuEPO, abbreviated as EPO) are the main treatment strategies for renal anaemia in HD patients, but it has not been clear whether there is a difference in their effect on LVH.

METHODS

In this multi-centre, prospective, randomized trial of 12-month duration, study participants were randomized in a 1:1 ratio to the roxadustat group or the EPO group. The doses of both treatment regimens were adjusted so that the patients had a haemoglobin level of 10.0-12.0 g per dL. The primary study endpoint was the change from baseline to 12 months in the left ventricular mass index (LVMI, g/m2) measured by echocardiography.

RESULTS

In total, 114 patients were enrolled. The mean age was 50 years, and the median dialysis duration was 33 months. Sixty-one patients were men, and 24 were diabetic. LVMI decreased from 116.18 ± 27.84 to 110.70 ± 25.74 g/m2 in the roxadustat group. However, it increased from 109.35 ± 23.41 to 114.99 ± 28.46 g/m2 in the EPO group, with a significant difference in the change in LVMI between the two groups [-5.48 (-11.60 to 0.65) vs. 5.65 (0.74 to 10.55), p < 0.05]. Changes in left ventricular mass, end-diastolic volume and 6-min walk test seemed superior in the roxadustat group. There were no significant differences in other cardiac geometry, biochemical parameters and major adverse cardiovascular events between the two groups.

CONCLUSIONS

Compared to EPO, roxadustat is more helpful in the regression of LVH in HD patients.

Deletion of Endothelial TRPV4 Protects Heart From Pressure Overload-Induced Hypertrophy

BACKGROUND

Left ventricular hypertrophy is a bipolar response, starting as an adaptive response to the hemodynamic challenge, but over time develops maladaptive pathology partly due to microvascular rarefaction and impaired coronary angiogenesis. Despite the profound influence on cardiac function, the mechanotransduction mechanisms that regulate coronary angiogenesis, leading to heart failure, are not well known.

METHODS

We subjected endothelial-specific knockout mice of mechanically activated ion channel, TRPV4 (transient receptor potential cation channel subfamily V member 4; TRPV4ECKO) to pressure overload via transverse aortic constriction and examined cardiac function, cardiomyocyte hypertrophy, cardiac fibrosis, and apoptosis. Further, we measured microvascular density and underlying TRPV4 mechanotransduction mechanisms using human microvascular endothelial cells, extracellular matrix gels of varying stiffness, unbiased RNA sequencing, small interfering RNA, Western blot, quantitative-PCR, and confocal immunofluorescence techniques.

RESULTS

We demonstrate that endothelial-specific deletion of TRPV4 preserved cardiac function, cardiomyocyte structure, and reduced cardiac fibrosis compared with TRPV4lox/lox mice, 28 days post-transverse aortic constriction. Interestingly, comprehensive RNA sequencing analysis revealed an upregulation of proangiogenic factors (VEGFα [vascular endothelial growth factor α], NOS3 [nitric oxide synthase 3], and FGF2 [fibroblast growth factor 2]) with concomitant increase in microvascular density in TRPV4ECKO hearts after transverse aortic constriction compared with TRPV4lox/lox. Further, an increased expression of VEGFR2 (vascular endothelial growth factor receptor 2) and activation of the YAP (yes-associated protein) pathway were observed in TRPV4ECKO hearts. Mechanistically, we found that downregulation of TRPV4 in endothelial cells induced matrix stiffness-dependent activation of YAP and VEGFR2 via the Rho/Rho kinase/large tumor suppressor kinase pathway.

CONCLUSIONS

Our results suggest that endothelial TRPV4 acts as a mechanical break for coronary angiogenesis, and uncoupling endothelial TRPV4 mechanotransduction attenuates pathological cardiac hypertrophy by enhancing coronary angiogenesis.

Associations of maternal angiogenic factors during pregnancy with alterations in cardiac development in childhood at 10 years of age

AIM

To examine whether maternal angiogenic factors in the first half of pregnancy are associated with offspring left and right cardiac development.

METHODS

In a population-based prospective cohort among 2,415 women and their offspring, maternal first and second trimester plasma PlGF and sFlt-1 concentrations were measured. Cardiac MRI was performed in their offspring at 10 years.

RESULTS

Maternal angiogenic factors were not associated with childhood cardiac outcomes in the total population. In children born small-for-their-gestational-age, higher maternal first trimester PlGF concentrations were associated with a lower childhood left ventricular mass  (-0.24 SDS  [95%CI -0.42, -0.05 per SDS increase in maternal PlGF]), whereas higher sFlt-1 concentrations were associated with higher childhood left ventricular mass  (0.22 SDS  [95%CI 0.09, 0.34 per SDS increase in maternal sFlt-1]). Higher second trimester maternal sFlt-1 concentrations were also associated with higher childhood left ventricular mass  (P-value <.05). In preterm born children, higher maternal first and second trimester sFlt-1/PlGF ratio were associated with higher childhood left ventricular mass  (0.30 SDS  [95%CI 0.01, 0.60], 0.22 SDS  [95%CI -0.03, 0.40]) per SDS increase in maternal sFlt-1/PlGF ratio in first and second trimester respectively). No effects on other childhood cardiac outcomes were present within these higher-risk children.

CONCLUSIONS

In a low-risk population, maternal angiogenic factors are not associated with childhood cardiac ventricular structure, and function within the normal range. In children born small for their gestational age or preterm, an imbalance in maternal angiogenic factors in the first half of pregnancy was associated with higher childhood left ventricular mass only.

The NLRP3 inflammasome: Multiple activation pathways and its role in primary cells during ventricular remodeling

Inflammasomes are a group of multiprotein signaling complexes located in the cytoplasm. Several inflammasomes have been identified, including NLRP1, NLRP2, NLRP3, AIM2, and NLRC4. Among them, NLRP3 was investigated in most detail, and it was reported that it can be activated by many different stimuli. Increased NLRP3 protein expression and inflammasome assembly lead to caspase-1 mediated maturation and release of IL-1β, which triggers inflammation and pyroptosis. The activation of the NLRP3 inflammasome has been widely reported in studies of tumors and neurological diseases, but relatively few studies on the cardiovascular system. Ventricular remodeling (VR) is an important factor contributing to heart failure (HF) after myocardial infarction (MI). Consequently, delaying VR is of great significance for improving heart function. Studies have shown that the NLRP3 inflammasome plays an essential role in the process of VR. Here, we reviewed the latest studies on the activation pathway of the NLRP3 inflammasome, focusing on the effects of the NLRP3 inflammasome in primary cells during VR, and finally discuss future research directions in this field.

The endocrinological component and signaling pathways associated to cardiac hypertrophy

Although myocardial growth corresponds to an adaptive response to maintain cardiac contractile function, the cardiac hypertrophy is a condition that occurs in many cardiovascular diseases and typically precedes the onset of heart failure. Different endocrine factors such as thyroid hormones, insulin, insulin-like growth factor 1 (IGF-1), angiotensin II (Ang II), endothelin (ET-1), catecholamines, estrogen, among others represent important stimuli to cardiomyocyte hypertrophy. Thus, numerous endocrine disorders manifested as changes in the local environment or multiple organ systems are especially important in the context of progression from cardiac hypertrophy to heart failure. Based on that information, this review summarizes experimental findings regarding the influence of such hormones upon signalling pathways associated with cardiac hypertrophy. Understanding mechanisms through which hormones differentially regulate cardiac hypertrophy could open ways to obtain therapeutic approaches that contribute to prevent or delay the onset of heart failure related to endocrine diseases.

Protective role of ErbB3 signaling in myeloid cells during adaptation to cardiac pressure overload

BACKGROUND

Myeloid cells play an important role in a wide variety of cardiovascular disorders, including both ischemic and non-ischemic cardiomyopathies. Neuregulin-1 (NRG-1)/ErbB signaling has recently emerged as an important factor contributing to the control of inflammatory activation of myeloid cells after an ischemic injury. However, the role of ErbB signaling in myeloid cells in non-ischemic cardiomyopathy is not fully understood. This study investigated the role of ErbB3 receptors in the regulation of early adaptive response using a mouse model of transverse aortic constriction (TAC) for non-ischemic cardiomyopathy.

METHODS AND RESULTS

TAC surgery was performed in groups of age- and sex-matched myeloid cell-specific ErbB3-deficient mice (ErbB3^MyeKO) and control animals (ErbB3^MyeWT). The number of cardiac CD45 immune cells, CD11b myeloid cells, Ly6G neutrophils, and Ly6C monocytes was determined using flow cytometric analysis. Five days after TAC, survival was dramatically reduced in male but not female ErbB3^MyeKO mice or control animals. The examination of lung weight to body weight ratio suggested that acute pulmonary edema was present in ErbB3^MyeKO male mice after TAC. To determine the cellular and molecular mechanisms involved in the increased mortality in ErbB3^MyeKO male mice, cardiac cell populations were examined at day 3 post-TAC using flow cytometry. Myeloid cells accumulated in control but not in ErbB3^MyeKO male mouse hearts. This was accompanied by increased proliferation of Sca-1 positive non-immune cells (endothelial cells and fibroblasts) in control but not ErbB3^MyeKO male mice. No significant differences in intramyocardial accumulation of myeloid cells or proliferation of Sca-1 cells were found between the groups of ErbB3^MyeKO and ErbB3^MyeWT female mice. An antibody-based protein array analysis revealed that IGF-1 expression was significantly downregulated only in ErbB3^MyeKO mice hearts compared to control animals after TAC.

CONCLUSION

Our data demonstrate the crucial role of myeloid cell-specific ErbB3 signaling in the cardiac accumulation of myeloid cells, which contributes to the activation of cardiac endothelial cells and fibroblasts and development of an early adaptive response to cardiac pressure overload in male mice.