Hypertension and the Heart

Trends by age and sex and projections of disease prevalence from studying hypertensive heart disease in China over the past three decades

BACKGROUND

Hypertensive heart disease (HHD) is a common cause of cardiovascular disease and mortality worldwide, and its burden is increasing with aging populations.

OBJECTIVES

This study aimed to estimate the prevalence and mortality rates of HHD in mainland China and Taiwan Province using data from the Global Burden of Disease Study 2019 (GBD 2019), and forecast the development trend of HHD from 2020 to 2024.

METHODS

We obtained data on number of cases, deaths, crude prevalence rate, crude death rate, age-standardized prevalence rate (ASPR), and age-standardized death rate (ASDR) for mainland China and Taiwan Province from 1990 to 2019 from the GBD 2019. Joinpoint software was used to estimate average annual percentage change (AAPC) with 95% confidence intervals, and the number of HHD cases in China from 2022 to 2024 was predicted by the exponential smoothing method.

RESULTS

Between 1990 and 2019, HHD cases and deaths increased in mainland China, but the ASPR and ASDR decreased by 5.96% and 48.72%, respectively. In Taiwan Province, ASPR and ASDR decreased by 7.66% and 52.14%, respectively. The number of HHD cases and death rates varied by region, age, and sex, with a higher number of cases in mainland China than in Taiwan Province. By 2024, the number of HHD cases in mainland China was projected to be over 9.6 million cases, and in Taiwan Province, it was projected to surpass 120,000 cases.

CONCLUSION

The differences in HHD cases between mainland China and Taiwan Province in terms of age and sex indicated the need for effective prevention and control measures, especially targeting the elderly population. These findings can inform policymakers and health professionals in the development of targeted prevention and treatment strategies and resource allocation for HHD in China.

Plasminogen Activator Inhibitor-1 4G/5G (rs1799889) Polymorphism in Chinese Patients with Diabetes Mellitus and Hypertension

Objective

To determine the plasminogen activator inhibitor-1 (PAI-1) 4G/5G (rs1799889) genotype of the subjects in a robust detection method and to explore the association of the PAI-1 4G/5G polymorphism with susceptibility to diabetes mellitus (DM) and hypertension (HTN) as well as clinical characteristics.

Methods

This study recruited 208 patients (68 patients were diagnosed with DM, 70 patients with HTN and 70 patients with DM combined with HTN) and 132 healthy controls (HC). A subset of the population was selected to evaluate the accuracy of the Real-time PCR (RT-PCR) method for detecting PAI-1 4G/5G polymorphism by using the sequencing method as the gold standard. Furthermore, the association of the PAI-1 4G/5G polymorphism with genetic susceptibility to DM and HTN was explored. Moreover, variations in clinical characteristics among individuals with various PAI-1 genotypes were also analyzed in the DM group, the HTN group and the DM+HTN group.

Results

There was a high concordance between the RT-PCR method and the sequencing method in determining the PAI-1 4G/5G polymorphism. No association was observed between the PAI-1 4G/5G polymorphism and susceptibility to DM, HTN and DM+HTN, respectively. There were no statistical differences in all study indicators among individuals that carrying various genotypes in the HC group. There were several variations in clinical characteristics among individuals harboring different PAI-1 4G/5G genotypes in the DM group, the HTN group and the DM+HTN group.

Conclusion

The RT-PCR method can accurately identify the PAI-1 4G/5G genotype in different individuals. The PAI-1 4G/5G polymorphism may not be associated with genetic susceptibility to DM, HTN and DM+HTN, but differences in clinical characteristics among individuals with various genotypes may provide a reference for disease assessment and personalized treatment of patients.

Inhibition of Rho/ROCK signaling pathway participates in the cardiac protection of exercise training in spontaneously hypertensive rats

Exercise training (ExT) is capable of improving the heart function of spontaneously hypertensive rats (SHRs), but the underlying molecular mechanisms remain elusive. This study was aimed to investigate whether inhibition of RhoA/ROCK signaling pathway contributes to the cardiac protection by low-intensity ExT in SHRs. The results demonstrated that, compared with Wistar-Kyoto (WKY) rats, SHRs obviously exhibited higher blood pressure, increased heart weight index and thickness of left ventricular wall, decreased left ventricular function, damaged myocardial construction, and increased collagen fiber of left ventricle (P < 0.05 or P < 0.01). Meanwhile, the mRNA and protein expression levels of RhoA and ROCK in the heart of SHRs were significantly increased, compared with those of WKY rats (P < 0.05 or P < 0.01). Interestingly, the pathological changes of heart aforementioned were all improved in SHR-ExT rats compared with SHR-Sed rats (P < 0.05 or P < 0.01), indicating the cardiac protection of exercise training. In addition, the cardiac protective effect of exercise training could be blocked by LPA, an activator of Rho/ROCK signaling, and the protective effect in SHR rats could be mimicked by Fasudil, an inhibitor of Rho/ROCK signaling. The results strongly suggest that low-intensity ExT can protect heart against structure and function through inhibiting Rho/ROCK signaling pathway in hypertensive rats.

Positive Effect of a Pea-Clam Two-Peptide Composite on Hypertension and Organ Protection in Spontaneously Hypertensive Rats

In the present study, we prepared pea peptides with high angiotensin-converting enzyme (ACE) inhibitory activity in vitro using an enzymatic hydrolysis of pea protein and compounded them with clam peptides to obtain a pea-clam double peptide. The effects of the two-peptide composite and pea peptides on hypertension and the damage-repair of corresponding organs were studied in spontaneously hypertensive rats (SHRs). We found that both pea peptides and the two-peptide composite significantly reduced the blood pressure upon a single or long-term intragastric administration, with the two-peptide composite being more effective. Mechanistically, we found that the two-peptide composite could regulate the renal renin-angiotensin system (RAS), rebalance gut microbial dysbiosis, decrease renal and myocardial fibrosis, and improve renal and cardiac function and vascular remodeling. Additionally, hippocampal lesions caused by hypertension were also eliminated after two-peptide composite administration. Our research provides a scientific basis for the use of this two-peptide composite as a safe antihypertension ingredient in functional foods.

Dietary omega-3 fatty acids attenuate myocardial arrhythmogenic factors and propensity of the heart to lethal arrhythmias in a rodent model of human essential hypertension

OBJECTIVE

Hypertension-induced myocardial remodeling is known to be associated with increased risk for malignant arrhythmias and alterations in electrical coupling protein, connexin-43 (Cx43), may be involved. We investigated whether omega-3 fatty acids intake affects abnormalities of Cx43 as well as protein kinase C (PKC) signaling and myosin heavy chain (MyHC) profile at the early and late stage of hypertension in the context of the heart's susceptibility to ventricular fibrillation and ability to restore sinus rhythm.

METHODS

Untreated young and old male spontaneously hypertensive rats (SHRs) and age-matched normotensive rats were compared with animals supplemented by omega-3 (eicosapentaneoic acid + docosahexaneoic acid, 200 mg/kg body weight/day) for 2 months. Left ventricular tissues were taken for examination of subcellular integrity of gap junctions, Cx43 mRNA and protein expression, PKCε and PKCδ as well as MyHC determination. Electrically inducible ventricular fibrillation and sinus rhythm restoration (SRR) were examined on Langedorff-perfused heart preparation.

RESULTS

Omega-3 intake significantly reduced cardiovascular risk factors, suppressed inducible ventricular fibrillation, and facilitated SRR in hypertensive rats. Supplementation attenuated lateralization and internalization of Cx43, suppressed elevated Cx43 mRNA, enhanced total Cx43 protein expression and/or expression of its functional phosphorylated forms as well as the expression of cardioprotective PKC-ε and suppressed pro-apoptotic PKC-δ isoform. Moreover, the omega-3 diet normalized MyHC profiles in SHR at early stage of disease and old nonhypertensive rats, but failed to do so in old SHR at late stage of disease.

CONCLUSION

Findings suggest that amelioration of myocardial Cx43-related abnormalities, positive modulation of PKC pathways, and normalization of MyHC can significantly contribute to the antiarrhythmic effects of omega-3 in rat model mimicking human essential hypertension. Our results support the prophylactic use of omega-3 to minimize cardiovascular risk and sudden arrhythmic death.

A model for left ventricular hypertrophy enabling non-invasive assessment of cardiac function

OBJECTIVE

To develop a porcine model for Left Ventricular Hypertrophy (LVH) in which cardiac performance could be quantified non-invasively by Doppler ultrasound.

DESIGN

Sixteen 5 kg piglets were divided into two groups. In the first group (n=12) we performed an aortic banding and in the second group (n=4) a sham-operation. Endpoints were echo-assessed left ventricular midseptal and free-wall thickness, heart/body-weight ratio and cardiac myocyte diameter.

RESULTS

Free-wall thickness: 0.77+/-0.013 cm in the intervention group and 0.60+/-0.006 cm in the control group (p=0.015). Midseptal thickness: 0.79+/-0.015 cm in the intervention group and 0.58+/-0.010 cm in the control group (p=0.012). Heart/body-weight ratio: 7.73+/-0.970 in the intervention group and 6.23+/-0.430 in the control group (p=0.003). Cardiac myocyte diameter: 19.6+/-4.9 microm in the intervention group and 11.0+/-1.9 microm in the control group (p=0.000).

CONCLUSION

A chronic porcine model for LVH has been established in which Doppler ultrasound can be used to quantify cardiac function non-invasively.

Landmarks in understanding the central nervous control of the cardiovascular system

In this Paton Lecture I have tried to trace the key experiments that have developed ideas on how the brain regulates the cardiovascular system. It is a personal view and inevitably, owing to constraints on space and time, I have not been able to cover areas such as the nucleus tractus solitarius and cardiac vagal neurones, although I acknowledge that some may consider the story is incomplete without them. Starting with the crucial discovery of vasomotor nerves and 'vasomotor tone', the patterns of activity in sympathetic nerves which led to the important idea of central oscillating networks of neurones are described. I discuss how this knowledge has informed current controversies on the origin of vasomotor activity in presympathetic neurones in the ventral medulla, which identify intrinsic pacemaker activity or synaptic input from multiple oscillators as prime mechanisms. I present an emerging view that the role of other regions of the brain, in particular supramedullary sites, has been underplayed. These regions are pivotal for the non-uniform distribution of cardiac output that is unique to each reflex and behavioural state. I discuss the most recent evidence for 'central command' neurones that offers a plausible explanation for how these patterns of sympathetic activity are achieved. Finally, I stress the importance of these current ideas to the understanding of pathological changes in sympathetic activity in cardiovascular diseases such as hypertension or congestive heart failure.