Hypertensive and heart disease complications fuel cardiovascular morbidity and mortality. Cardiovascular diseases, especially hypertension, have been established to change the tissue structure and composition of the left ventricle (LV) and ultimately change the mechanical behavior (Grobbel et al., 2021). Long-term exposure to high pressure can lead to pathological features such as cardiomyocyte hypertrophy, fibrosis, and increased resting tension of myocytes in the left ventricle, leading to centripetal hypertrophy (Borlaug, 2020; Mishra and Kass, 2021; Nair, 2020). Although antihypertensive drugs can control blood pressure, it is difficult to protect target organs from long-term damage completely. Therefore, the ability to effectively reduce heart damage while maintaining blood pressure remains to be resolved.

A long-term high salt diet is one of the most critical environmental factors for hypertension (Bier et al., 2018; Rucker et al., 2018). The evidence has revealed that excessive dietary salt in rats can lead to coronary artery perivascular fibrosis, ventricular interstitial fibrosis, ventricular ischemia and ventricular diastolic dysfunction (Gao et al., 2011). A key aspect of hypertensive heart disease is cardiac fibrosis. Fibrosis, a surplus extracellular matrix, is detrimental that promotes contractile dysfunction. However, due to the complex pathological process of hypertensive heart disease, cardiovascular medicines with a single mechanism are unable to provide systematic and thorough heart protection. Therefore, these medical challenges must be solved if more patients are to stay away from the life-threatening risks caused by hypertensive heart disease and improve their quality of life. Traditional Chinese medicine has few side effects on cardiovascular disease and contains the synergistic effect of a variety of active and effective compounds, so TCM has shown great advantages in the treatment of heart damage with hypertension.

Qishen Yiqi (QSYQ) is a China State Food and Drug Administration-approved component-based Chinese medicine. It consists of Astragalus, Salvia miltiorrhiza, Panax notoginseng, and Dalbergia odorifera, blended in accordance with TCM theory of invigorating the qi, enhancing blood circulation and dissipating blood stasis. Clinically, it is mainly used to treat coronary heart disease, angina pectoris and secondary prevention of myocardial infarction. It has been reported that the main components of QSYQ include danshensu, rosmarinic acid, protocatechualdehyde, calycosin-7-O-β-D-glucoside, and ononin (Xie et al., 2021). Studies have shown that QSYQ improves ischemia/reperfusion-induced myocardial fibrosis by regulating TGFβ1/Smads signaling pathway (Zheng et al., 2019). QSYQ and its components have a protective effect on myocardial ischemia by regulating energy metabolism (Cui et al., 2018). QSYQ alleviates cardiac hypertrophy and dysfunction caused by fatigue by modulating energy metabolism (Huang et al., 2019). Our previous studies showed that QSYQ could reduce blood pressure and improve kidney damage in Dahl salt-sensitive rats (Du et al., 2021). However, the cardioprotective effect of QSYQ on Dahl salt-sensitive rats has not been explored. Therefore, this article mainly studies QSYQ on the protective potential of heart injury in salt-sensitive hypertension rats.

Uncontrolled blood pressure leads to myocardial remodeling. Fibrosis is the pathophysiological basis of hypertension and ultimately leads to heart failure. Myocardial fibrosis is considered an early event of heart failure. Fibrosis is caused by fibrotic factors, collagen synthesis and degradation, upregulation of extracellular matrix and increased oxidative stress. Periostin (POSTN) is a 90 kDa peptide secreted from the resident cardiac fibroblasts and myofibroblasts located in the fibrous barrier between the valve, atrium, ventricle, and ventricular myocardium. The main structure of the peptide is four repeated fasciclin (Litvin et al., 2006), which can promote the process of fibrosis by regulating ECM homeostasis (Liu et al., 2014). POSTN has very low expression levels in heart-healthy mesenchymal cells, including valve interstitial cells, vascular smooth muscle cells and cardiac fibroblasts. However, POSTN is essential in activating fibroblasts to secrete proteome in damaged hearts (Kanisicak et al., 2016). Studies have shown that the upregulation of POSTN expression in human failing hearts is related to myocardial fibrosis (Zhao et al., 2014). Another study conducted on mice after transected aorta narrowing confirmed the role of POSTN in heart failure (Liu et al., 2013). However, the therapeutic implications of POSTN modulation remain paradoxical in hypertensive cardiomyopathy pathogenesis. Notably, while these findings establish POSTN as a biomarker of advanced fibrotic deterioration, current clinical evidence remains insufficient to validate its direct cardioprotective potential against hypertension-induced myocardial injury. All in all, POSTN may play a vital role in the prevention of hypertensive heart damage.

Critical to understanding the biology of hypertension and associated cardiovascular disorders is the generation of angiotensin II (Ang II) (Zoungas and Asmar, 2007). Ang II increases arterial pressure by inducing intense vasoconstriction and promoting the reuptake of sodium and water in the renal tubules, increasing arterial pressure and damaging the heart. Based on previous research, experimental models of Ang II-induced hypertension are accompanied by the occurrence of cardiac remodeling processes (Johar et al., 2006). Furthermore, Ang II is the most important hormone for regulating myocardial fibrosis (Bai et al., 2013; Kuwabara et al., 2022), and previous studies have shown that Ang II antagonists can prevent fibrosis in various diseases (Klein et al., 2017; Shenoy et al., 2010). Therefore, it is reasonable to use a vitro model induced by Ang II to explore the study of QSYQ on hypertensive cardiac fibrosis. However, the structure of the heart is complex, consisting of multiple layers of tissue and different types of cells that work together to ensure the proper functioning of the heart (Hofbauer et al., 2021). However, the two-dimensional (2D) cell, the most widely and traditionally used in vitro cell models of the heart, is difficult to reproduce in vivo environments and supply the three-dimensional (3D) models needed for cell-cell and cell-matrix interactions (Lee et al., 2020). Combining both 2D and 3D cardiac spheroid in vitro models suppotrs not only 3D cell-cell and cell-matrix interactions but also performs multi-dimensional model evaluation, so that it is an ideal model to study cardiac fibrosis in vitro.

In this study, utilizing Dahl salt-sensitive rat models with 3D cardiac spheroids and 2D fibroblasts, we demonstrated that QSYQ attenuates hypertensive cardiac remodeling by suppressing POSTN-driven fibrotic signaling. Mechanistically, QSYQ treatment: (1) downregulated pathological POSTN overexpression in pressure-overloaded myocardium, (2) inhibited fibroblast activation in spheroids, and (3) reduced collagen hypersecretion in vitro. These multi-dimensional analyses establish QSYQ’s cardioprotection as being mediated through POSTN inhibition, repositioning this traditional formulation as a targeted modulator of fibrotic pathways. Our findings provide mechanistic justification for QSYQ’s therapeutic application in hypertensive cardiomyopathy via strategic interception of POSTN-mediated maladaptive remodeling.

We have made three new findings in this study. First, in vivo study using Dahl hypertension rats demonstrated that a long-term high salt diet led to severe heart hypertrophy and fibrosis. QSYQ significantly improved cardiac function, attenuated myocardial hypertrophy and fibrosis. Second, we showed that QSYQ protects against hypertensive cardiac fibrosis and heart damage at least in part by regulating multiple signaling pathway activator periostin. Third, using Ang II treatment of cardiac spheroids induced hypertrophy and fibrosis in vitro. QSYQ reversed hypertrophic and fibrotic phenotypes and downregulated the expression of periostin and related hypertrophic and fibrotic genes (Figure 9).

Dahl salt-sensitive (Dahl SS) rat is a strain of hypertensive animals that develop systemic hypertension based on the sodium content provided in the diet (Dahl et al., 1962; Zicha et al., 2012). Dahl SS rats fed a high-salt diet increased systolic blood pressure of more than 200 mmHg due to a combination of pressure and volume overload and a high-salt diet for five to 6 weeks led to compensatory left ventricular hypertrophy (Tran et al., 2016). Dahl SS rats developed heart failure after 10–12 weeks of a high-salt diet, accompanied by left ventricular dilatation and systolic dysfunction (Iwanaga et al., 1998). Our study confirms these rats suffer from diastolic dysfunction after 9 weeks on a high-salt diet (Figure 1). QSYQ treatment notably improves diastolic function and reduces cardiac hypertrophy and fibrosis in these rats (Figure 2), suggesting its effectiveness in mitigating cardiac damage from salt-sensitive hypertension.

Recent studies have found that Traditional Chinese medicines and other herbal medicines protect against hypertensive heart damage in Dahl salt-sensitive hypertensive rats. Guizhi Decoction, Guizhi Decoction, comprising ingredients like Guizhi and ginger, improves myocardial fibrosis by modulating NGF and LIF levels, slowing heart failure progression (Wang et al., 2020). Xiao-Qing-Long-Tang, with components such as ephedra and licorice, maintains cardiac function by correcting sympathetic nervous system imbalances (Li et al., 2020). Puerarin improves vascular insulin resistance and cardiovascular remodeling in salt-sensitive hypertension (Tan et al., 2017). Investigating QSYQ’s effects, RNA sequencing revealed 307 differentially expressed genes associated with inflammation and organ injury (Figure 3). RT-qPCR confirmed the significant upregulation of POSTN, a gene closely linked to hypertensive heart damage (Figure 3). Thus, integrated analyses suggest that hypertensive conditions increase POSTN expression in cardiac tissue.

Cardiac fibrosis is a common and key pathological process leading to heart failure in various heart diseases (Frangogiannis, 2021). Our results provided an in vitro 3D model of hypertensive heart disease. Early studies have shown that Ang II not only raises blood pressure but also induces cardiac hypertrophy and myocardial expansion (De Mello and Danser, 2000; Sadoshima and Izumo, 1993; Schlüter and Wenzel, 2008). It is interesting that Ang II has been shown to stimulate significant growth in other cell types, such as fibroblasts, in addition to the hypertrophy of cardiomyocytes (Kim and Iwao, 2000; Verma et al., 2021), which ultimately leads to fibrosis. We have developed a 3D spheroid model that mimics hypertensive heart disease in vitro, displaying hypertrophy and fibrosis when treated with Ang II (Figures 5–7). This model effectively replicates the key characteristics of heart fibrosis and allows for the study of intercellular signaling relevant to the disease.

A large amount of evidence indicates that POSTN plays a vital role in coronary artery disease and cardiac fibrosis caused by hypertension (Wu et al., 2016; Zhao et al., 2014). As an extracellular matrix (ECM) protein, Periostin is prominently expressed in fibrotic tissue (Mael-Ainin et al., 2014; Okamoto et al., 2011; Wallace et al., 2014), influenced by TGF-β pathways in mesenchymal cells, a key factor in fibrosis (Ashley et al., 2017; Egbert et al., 2014). High salt intake by Dahl SS rats leads to hypertension, ventricular hypertrophy, and heart failure (Tran et al., 2016). Myocardial fibrosis in these rats is linked to TGFβ activation, and TGFβ1 can induce POSTN expression in cardiac and vascular cells (Li et al., 2006; Snider et al., 2008). POSTN also interacts with ECM components like fibronectin, affecting tissue biomechanics (Kii et al., 2010). Ang II increases arterial pressure by inducing vasoconstriction and promoting sodium and water reuptake in the renal tubules (Failer et al., 2022), promotes systemic arteriole constriction, causes hypertension by binding to Ang II type I receptors, and contributes to fibrosis in hypertension-related heart disease (Funck et al., 1997; Maning et al., 2017). Therefore, in vitro experiments were performed in this study using cardiac organoids treated with Ang II to investigate the effect of POSTN on hypertensive cardiac fibrosis (Figure 6). Studies have shown that the expression of POSTN is increased in hypertensive hearts (Figure 8). Inhibiting the expression of POSTN may be a promising method to attenuate the heart remodeling caused by hypertension (Wu et al., 2016). QSYQ was found to lower blood pressure (Du et al., 2021), reduce diastolic dysfunction and hypertrophy, and alleviate cardiac fibrosis in hypertensive rats, suggesting that QSYQ’s cardioprotective effects stem from lowering POSTN and TGF-β expression, inhibiting collagen synthesis, and reducing ECM formation, potentially inhibiting fibrosis progression. (Figures 4, 7, 8).

Our study indicates that QSYQ mitigates myocardial damage in salt-sensitive hypertensive conditions by modulating the expression of fibrotic genes such as POSTN and TGF-β. Nevertheless, further investigation is necessary due to: (1) differences between animal models and human pathology, limiting direct translation of findings to humans, (2) the need to identify which components of QSYQ crucially influence fibrosis pathways, and (3) the necessity to explore other key transcriptome genes, such as Uchl1 and Ucp3, for a comprehensive understanding of the multi-component and multi-targeted action of traditional Chinese medicine.

Our research showed that QSYQ effectively improves cardiac function and reduces hypertrophy and fibrosis in salt-sensitive hypertensive rats, at least in part due to its regulatory effect on the signaling activator periostin. This suggests QSYQ’s therapeutic promise for salt-sensitive hypertensive cardiac injury by targeting hypertrophic and fibrotic pathways.