Of Mouse and Man: Cross-Species Characterization of Hypertensive Cardiac Remodeling

Role of the Lymphatics in Cardiac Disease

Cardiovascular diseases remain the largest cause of death worldwide with recent evidence increasingly attributing the development and progression of these diseases to an exacerbated inflammatory response. As a result, significant research is now focused on modifying the immune environment to prevent the disease progression. This in turn has highlighted the lymphatic system in the pathophysiology of cardiovascular diseases owing, in part, to its established function in immune cell surveillance and trafficking. In this review, we highlight the role of the cardiac lymphatic system and its potential as an immunomodulatory therapeutic target in selected cardiovascular diseases.

Hypertensive Heart Disease: Mechanisms, Diagnosis and Treatment

Hypertensive heart disease (HHD) presents a substantial global health burden, spanning a spectrum from subtle cardiac functional alterations to overt heart failure. In this comprehensive review, we delved into the intricate pathophysiological mechanisms governing the onset and progression of HHD. We emphasized the significant role of neurohormonal activation, inflammation, and metabolic remodeling in HHD pathogenesis, offering insights into promising therapeutic avenues. Additionally, this review provided an overview of contemporary imaging diagnostic tools for precise HHD severity assessment. We discussed in detail the current potential treatments for HHD, including pharmacologic, lifestyle, and intervention devices. This review aimed to underscore the global importance of HHD and foster a deeper understanding of its pathophysiology, ultimately contributing to improved public health outcomes.

Semiautomated pipeline for quantitative analysis of heart histopathology

BACKGROUND

Heart diseases are among the leading causes of death worldwide, many of which lead to pathological cardiomyocyte hypertrophy and capillary rarefaction in both patients and animal models, the quantification of which is both technically challenging and highly time-consuming. Here we developed a semiautomated pipeline for quantification of the size of cardiomyocytes and capillary density in cardiac histology, termed HeartJ, by generating macros in ImageJ, a broadly used, open-source, Java-based software.

METHODS

We have used modified Gomori silver staining, which is easy to perform and digitize in high throughput, or Fluorescein-labeled lectin staining. The latter can be easily combined with other stainings, allowing additional quantitative analysis on the same section, e.g., the size of cardiomyocyte nuclei, capillary density, or single-cardiomyocyte protein expression. We validated the pipeline in a mouse model of cardiac hypertrophy induced by transverse aortic constriction, and in autopsy samples of patients with and without aortic stenosis.

RESULTS

In both animals and humans, HeartJ-based histology quantification revealed significant hypertrophy of cardiomyocytes reflecting other parameters of hypertrophy and rarefaction of microvasculature and enabling the analysis of protein expression in individual cardiomyocytes. The analysis also revealed that murine and human cardiomyocytes had similar diameters in health and extent of hypertrophy in disease confirming the translatability of our murine cardiac hypertrophy model. HeartJ enables a rapid analysis that would not be feasible by manual methods. The pipeline has little hardware requirements and is freely available.

CONCLUSIONS

In summary, our analysis pipeline can facilitate effective and objective quantitative histological analyses in preclinical and clinical heart samples.

Farrerol prevents Angiotensin II-induced cardiac remodeling in vivo and in vitro

Cardiovascular disease has become the primary disease that threatens human health and is considered the leading cause of death. Cardiac remodeling, which is associated with cardiovascular disease, mainly manifests as cardiac hypertrophy, fibrosis, inflammation, and oxidative stress. Farrerol plays an important role in treating conditions such as inflammation, endothelial injury and tumors, and we speculated that Farrerol may also play an important role in mitigating cardiac hypertrophy and remodeling. We established a model of myocardial remodeling using Angiotensin II (Ang II) with concurrent intraperitoneal injection of Farrerol as an intervention. We used cardiac ultrasound, immunohistochemistry, Immunofluorescence, Wheat Germ Agglutinin, Dihydroethidium, Western Blot, qPCR and other methods to detect the role of Farrerol in cardiac remodeling. The results showed that Farrerol inhibited Ang II-induced cardiac hypertrophy; decreased the ratio of heart weight to tibia length in mice; reduced inflammation, fibrosis, and oxidative stress; and reduced the size of cardiomyocytes in vivo. Farrerol inhibited Ang II-induced cardiomyocyte hypertrophy, levels of oxidative stress, and the proliferation and migration of fibroblast in vitro. Our results revealed that Farrerol could inhibit Ang II-induced cardiac remodeling. Farrerol may therefore be a candidate drug for the treatment of myocardial remodeling.

The high-intensity interval training mitigates the cardiac remodeling in spontaneously hypertensive rats

AIM

To evaluate the influence of high-intensity interval training (HIIT) on cardiac structural and functional characteristics and myocardial mitogen-activated protein kinase (MAPK) signaling in hypertensive rats.

METHODS

Male rats (12 months old) were divided into three groups: Wistar Kyoto rats (WKY, n = 8); sedentary spontaneously hypertensive rats (SED-SHR, n = 10), and trained spontaneously hypertensive rats (HIIT-SHR, n = 10). Systolic blood pressure (SBP), functional capacity, echocardiography, isolated papillary muscle, and gene expression of MAPK gene-encoding proteins associated with Elk1, cJun, ATF2, MEF2 were analyzed.

KEY FINDINGS

HIIT decreased SBP and increased functional capacity, left ventricular diastolic diameter, posterior wall thickness-left ventricle, relative wall thickness-left ventricle, and resting tension of the papillary muscle. In hypertensive rats, we observed a decrease in the gene-encoding ATF2 protein; this decrease was reversed by HIIT.

SIGNIFICANCE

The influence of HIIT in the SHR model in the compensated hypertension phase generated an increase in cardiac hypertrophy, attenuated myocardial diastolic dysfunction, lowered blood pressure, improved functional capacity, and reversed the alteration in gene-encoding ATF2 protein.