Molecular mechanisms of left ventricular hypertrophy (LVH) in systemic hypertension (SH)—possible therapeutic perspectives

Hypertension and Heart Failure: From Pathophysiology to Treatment

Hypertension represents one of the primary and most common risk factors leading to the development of heart failure (HF) across the entire spectrum of left ventricular ejection fraction. A large body of evidence has demonstrated that adequate blood pressure (BP) control can reduce cardiovascular events, including the development of HF. Although the pathophysiological and epidemiological role of hypertension in the development of HF is well and largely known, some critical issues still deserve to be clarified, including BP targets, particularly in HF patients. Indeed, the management of hypertension in HF relies on the extrapolation of findings from high-risk hypertensive patients in the general population and not from specifically designed studies in HF populations. In patients with hypertension and HF with reduced ejection fraction (HFrEF), it is recommended to combine drugs with documented outcome benefits and BP-lowering effects. In patients with HF with preserved EF (HFpEF), a therapeutic strategy with all major antihypertensive drug classes is recommended. Besides commonly used antihypertensive drugs, different evidence suggests that other drugs recommended in HF for the beneficial effect on cardiovascular outcomes exert advantageous blood pressure-lowering actions. In this regard, type 2 sodium glucose transporter inhibitors (SGLT2i) have been shown to induce BP-lowering actions that favorably affect cardiac afterload, ventricular arterial coupling, cardiac efficiency, and cardiac reverse remodeling. More recently, it has been demonstrated that finerenone, a non-steroidal mineralocorticoid receptor antagonist, reduces new-onset HF and improves other HF outcomes in patients with chronic kidney disease and type 2 diabetes, irrespective of a history of HF. Other proposed agents, such as endothelin receptor antagonists, have provided contrasting results in the management of hypertension and HF. A novel, promising strategy could be represented by small interfering RNA, whose actions are under investigation in ongoing clinical trials.

The vascular footprint in cardiac homeostasis and hypertensive heart disease-A link between apelin receptor, vascular endothelial growth factor, and neuronal nitric oxide synthase

Recent studies have suggested a connection between disturbances of the apelin system and various cardiac pathologies, including hypertension, heart failure, and atherosclerosis. Vascular endothelial growth factor is crucial for cardiac homeostasis as a critical molecule in cardiac angiogenesis. Neuronal nitric oxide synthase is an essential enzyme producing nitric oxide, a key regulator of vascular tone. The present study aims to shed light upon the complex interactions between these three vital signaling molecules and examine their changes with the progression of hypertensive heart disease. We used two groups of spontaneously hypertensive rats and age-matched Wistar rats as controls. The expression of the apelin receptor, vascular endothelial growth factor, and neuronal nitric oxide synthase were assessed immunohistochemically. We used capillary density and cross-sectional area of the cardiomyocytes as quantitative parameters of cardiac hypertrophy. Immunoreactivity of the molecules was more potent in both ventricles of spontaneously hypertensive rats compared with age-matched controls. However, capillary density was lower in both ventricles of the two age groups of spontaneously hypertensive rats compared with controls, and the difference was statistically significant. In addition, the cross-sectional area of the cardiomyocytes was higher in both ventricles of the two age groups of spontaneously hypertensive rats compared with controls, and the difference was statistically significant. Our study suggests a potential link between the apelin receptor, vascular endothelial growth factor, and neuronal nitric oxide synthase in cardiac homeostasis and the hypertensive myocardium. Nevertheless, further research is required to better comprehend these interactions and their potential therapeutic implications.

Hypertensive heart disease: risk factors, complications and mechanisms

Hypertensive heart disease constitutes functional and structural dysfunction and pathogenesis occurring primarily in the left ventricle, the left atrium and the coronary arteries due to chronic uncontrolled hypertension. Hypertensive heart disease is underreported and the mechanisms underlying its correlates and complications are not well elaborated. In this review, we summarize the current understanding of hypertensive heart disease, we discuss in detail the mechanisms associated with development and complications of hypertensive heart disease especially left ventricular hypertrophy, atrial fibrillation, heart failure and coronary artery disease. We also briefly highlight the role of dietary salt, immunity and genetic predisposition in hypertensive heart disease pathogenesis.

Multi-effective characteristics and advantages of acupuncture in COVID-19 treatment

Coronavirus disease 2019 (COVID-19) is a major disease that threatens human life and health. Its pathogenesis is complex and still not fully clarified. The clinical treatment is mainly supportive and lacks specific treatment methods. Acupuncture treatment can inhibit immune inflammatory reactions, neuroinflammatory reactions, oxidative stress levels, and hypothalamus-pituitary-adrenal (HPA) axis activity, improve lung function, and relieve migraine, fatigue, anxiety, and depression. However, whether acupuncture treatment is suitable for treating these symptoms in patients with COVID-19 still needs to be investigated. For this review, the literature was systematically searched for multiple databases to summarize the mechanisms of acupuncture treatment for COVID-19-related symptoms and complications. A complex network analysis of acupoints and symptoms was also performed to clarify acupoint selection in the acupuncture treatment of symptoms related to COVID-19. The evidence indicates that acupuncture can improve the respiratory, digestive, nervous, and mental and psychological symptoms related to COVID-19 by inhibiting immune inflammatory reactions, regulating intestinal flora, mitochondrial function, oxidative stress level, cardiomyocyte apoptosis, neurotransmitter release, and HPA axis activity, and alleviating basic diseases such as diseases of the vascular system. Acupuncture can improve various clinical and concomitant symptoms of COVID-19; however, its mechanism of action is complex and requires further study.

Graphical abstract

http://links.lww.com/AHM/A54.

Pharmacological properties of total flavonoids in Scutellaria baicalensis for the treatment of cardiovascular diseases

BACKGROUND

Scutellaria baicalensis, a medicinal herb belonging to the Lamiaceae family, has been recorded in the Chinese, European, and British Pharmacopoeias. The medicinal properties of this plant are attributed to the total flavonoids of Scutellaria baicalensis (TFSB), particularly the main component, baicalin. This study provides a systematic and comprehensive list of the identified TFSB components and their chemical structures. The quality control process, pharmacokinetics, clinical application, and safety of Scutellaria baicalensis are discussed, and its pharmacological effect on cardiovascular diseases (CVDs) is detailed. Finally, the future research trends and prospects of this medicinal plant are provided.

METHODS

The Chinese and English papers related to TFSB were collected from the PubMed and CNKI databases using the relevant keywords. To highlight the pharmacological mechanism, clinical application, and safety of TFSB, the collected articles were screened and classified based on their research content.

RESULTS

TFSB contains at least 100 different kinds of flavonoids, of which baicalin, baicalein, wogonin, wogonoside, scutellarin, and scutellarein are the main active ingredients. The preparation process of TFSB is relatively well established, and the extraction rate can be significantly increased by enzymatic pretreatment and ultrasonication. The low oral availability of TFSB may be effectively enhanced using nanoformulations. The available pharmacokinetic data show that flavonoid glycosides and aglycones with the same parent nucleus may be converted to structures that are conducive to absorption in vivo. Moreover, TFSB can protect against CVDs by inhibiting apoptosis, regulating oxidative stress response, participating in inflammatory response, protecting against myocardial fibrosis, inhibiting myocardial hypertrophy, and regulating blood vessels. In terms of clinical application and animal safety, the available studies show that TFSB can be applied in a wide range of clinical treatments and is safe to use is animals.

CONCLUSION

This article systematically reviews the therapeutic effect and underlying pharmacological mechanism of TFSB against CVDs. The available studies clearly suggest that TFSB has great potential for the treatment of CVDs and is worthy of in-depth research and development.

Insulin-like growth factor-1 levels are associated with interventricular septal thickening

BACKGROUND AND OBJECTIVE

Insulin-like growth factor-1 (IGF-1) regulates cardiomyocyte survival, hypertrophy, and ageing. We aimed to investigate the potential correlation between IGF-1 and interventricular septal (IVS) thickening.

METHODS

Medical record data were obtained from patients hospitalized between May 1, 2012 and April 30, 2022. All patients underwent echocardiography and had laboratory data on plasma IGF-1. We analyzed the relationship between IGF-1 levels and IVS thickening based on logistic regression models.

RESULTS

Propensity score matching at 1:4 ratio was performed for 180 patients with IVS thickening and 1,964 patients without IVS thickening. Finally, 180 (case group) and 623 (control group) patients were enrolled. Of the total 803 patients, the mean age was 59 years, and 59.7% were male. In multivariate-adjusted models that adjusted for propensity scores, the risk of IVS thickening increased with increasing IGF-1 levels; specifically, the risk of IVS thickening increased per 1 ng/mL [odds ratio (OR) 1.003; 95% confidence interval (CI): 1.002-1.004; P < 0.001], per 5 ng/mL (OR, 1.016; 95% CI, 1.010-1.022; P < 0.001), and per 10 ng/mL(OR, 1.032; 95% CI, 1.019-1.045; P < 0.001) increase in IGF-1 levels. When the IGF-1 levels were expressed as a categorical variable, the increased levels of IGF-1 led to an increased risk of IVS thickening; specifically, the OR of IVS thickening for T3 >152.00 ng/mL was 2.020 (95% CI: 1.310-3.115, P < 0.01) compared with T1 <102.00 ng/mL. We performed restricted cubic splines, and it showed a linear association between IGF-1 levels and the risk of IVS thickening. In splines for the age and sex subgroups, different IGF-1 levels increased the risk of IVS thickening among different age groups in male patients: 18-44 years when IGF-1 value >164.00 ng/mL, 45-60 years when IGF-1 value > 140.34 ng/mL and ≥ 60 years when IGF-1 value >108.20 ng/mL. In female patients aged 45-60 years, the risk of IVS thickening increased when the IGF-1 levels were >207.45 ng/mL. However, IGF-1 was not significantly correlated with IVS thickening in female patients aged 18-45 and ≥60 years. Sensitivity analysis by excluding those with acromegaly did not change the relationship between IGF-1 and the risk of IVS thickening.

CONCLUSION

The plasma IGF-1 levels were related to the risk of IVS thickening irrespective of blood pressure.

MicroRNAs Regulating Renin-Angiotensin-Aldosterone System, Sympathetic Nervous System and Left Ventricular Hypertrophy in Systemic Arterial Hypertension

MicroRNAs are small non-coding RNAs that regulate gene and protein expression. MicroRNAs also regulate several cellular processes such as proliferation, differentiation, cell cycle, apoptosis, among others. In this context, they play important roles in the human body and in the pathogenesis of diseases such as cancer, diabetes, obesity and hypertension. In hypertension, microRNAs act on the renin-angiotensin-aldosterone system, sympathetic nervous system and left ventricular hypertrophy, however the signaling pathways that interact in these processes and are regulated by microRNAs inducing hypertension and the worsening of the disease still need to be elucidated. Thus, the aim of this review is to analyze the pattern of expression of microRNAs in these processes and the possible associated signaling pathways.

Caspase-1 Abrogates the Salutary Effects of Hypertrophic Preconditioning in Pressure Overload Hearts via IL-1β and IL-18

Cardiac hypertrophic preconditioning (HP) signifies cardioprotection induced by transient pressure overload to resist hypertrophic effects of subsequently sustained pressure overload. Although it is recently found that inflammation triggers the development of nonischemic cardiomyopathy, whether inflammation plays a role in the antecedent protective effects of HP remains unknown. Caspase-1 is a critical proinflammatory caspase that also induces pyroptosis; thus, we investigated the role of caspase-1 using a unique model of HP in mice subjected longitudinally to 3 days of transverse aortic constriction (TAC 3d), 4 days of de-constriction (De-TAC 4d), and 4 weeks of Re-TAC (Re-TAC 4W). Echocardiography, hemodynamics, histology, PCR, and western blot confirmed preserved cardiac function, alleviated myocardial hypertrophy and fibrosis, and less activated hypertrophic signaling effectors in Re-TAC 4W mice, compared with TAC 4W mice. Mechanistically, caspase-1 and its downstream targets IL-1β and IL-18, but not GSDMD, were less activated in Re-TAC 4W mice. Furthermore, in HP mice with AAV-9-mediated cardiac-specific caspase-1 overexpression, the salutary effects of HP were remarkably abrogated, as evidenced by exacerbated cardiac remodeling, dysfunction, and activation of IL-1β and IL-18. Collectively, this study revealed a previously unrecognized involvement of caspase-1 in cardiac HP by regulation of IL-1β and IL-18 and shed light on caspase-1 as an antecedent indicator and target for cardiac hypertrophy.

Serum Uric Acid and Left Ventricular Mass in Essential Hypertension

Serum uric acid (sUA) has been associated with cardiovascular risk. Although the recent mechanistic hypothesis poses the basis for the association between sUA and left ventricular mass index (LVMi), the issue remains poorly investigated in a clinical setup. Through a retrospective analysis of the database of the departmental Hypertension Clinic of University Hospital of Salerno Medical School, we identified 177 essential hypertensives (age 60.3 ± 13.3 years; 85 men), free from uric acid-modulating medications and severe chronic kidney disease, and whose sUA values, anthropometric, clinical, and echocardiographic data were available. In the studied cohort, the average duration of hypertension was 8.4 ± 7.1 years. LVMi associated with classical determinants, such as age, blood pressure, and kidney function, although after multivariate correction, only age remained significant. Also, sUA correlated positively with LVMi, as well as body size, metabolism, and kidney function. In a multivariate analysis, sUA confirmed the independent association with LVMi. Also, levels of sUA >5.6 mg/dl are associated with larger cardiac size. We confirmed our data in a replicate analysis performed in a larger population (1,379 hypertensives) from an independent clinic. Our results demonstrate that sUA increases with LVMi, and a cutoff of 5.6 mg/dl predict larger LV sizes. Our data suggest that hyperuricemia might help to stratify the risk of larger cardiac size in hypertensives.

Impaired fasting plasma glucose is a risk indicator of interventricular septum thickening among non-diabetic subjects with obesity

AIMS

To evaluate whether progressively higher fasting plasma glucose (FPG) is associated to thickening of the interventricular septum (IVS) among non-diabetic subjects with obesity.

METHODOLOGY

We studied 227 consecutive non diabetic patients (155 women and 72 men, age range 18-72 years) with overweight or obesity (BMI ≥ 25 Kg/m2), taking no medication or supplement. Hormonal, metabolic and routine laboratory parameters were collected. Echocardiography and ultrasonography echo-color Doppler of intima-media thickness of the common carotid artery (IMT-CCA) were performed to evaluate intima-media thickness of the common carotid artery (IVST) and early signs of atherosclerosis, respectively, in all enrolled subjects.

RESULTS

Of the 227 subjects, 48.9% had higher IVST values. Age (p 0.04), waist circumference (p 0.01), systolic (p < 0.01) and diastolic blood pressure (p < 0.01), FPG (p < 0.01), insulin (p 0.04), HOMA IR (p = 0.01), uric acid (p < 0.01) serum levels, IMT-CCA (p < 0.01), and left atrial diameter (LAD) (p < 0.01) were significantly higher in subjects with pathological IVST. Logistic regression models demonstrated an independent relation of FPG to IVST, both in semi and fully adjusted models (ORs 1.045 and 1.039, respectively). Moreover, graph presentation of the ORs and 95% CIs by FPG quintiles showed a positive risk trend for pathological IVST.

CONCLUSIONS

Higher FPG levels represent an independent sensitive predictor of IVS thickening in subjects with obesity, even before overt diabetes. These results emphasize the importance of preventive management of the diabetes risk in obesity.

Prevention of Heart Failure in Hypertension-Disentangling the Role of Evolving Left Ventricular Hypertrophy and Blood Pressure Lowering: The ALLHAT Study

Background

Hypertension is a known risk factor for heart failure (HF), possibly via the mechanism of cardiac remodeling and left ventricular hypertrophy (LVH). We studied the extent to which blood pressure (BP) change and evolving LVH contribute to the effect that lisinopril, doxazosin, and amlodipine have on HF compared with chlorthalidone.

Methods and Results

We conducted causal mediation analysis of ALLHAT (Antihypertensive and Lipid‐Lowering Treatment to Prevent Heart Attack Trial) data (1994‐2002; in‐trial follow‐up). ALLHAT participants with available serial ECGs and BP measurements were included (n=29 892; mean age 67±4 years; 32% black; 56% men): 11 008 were randomized to chlorthalidone, 5967 to doxazosin, 6593 to amlodipine, and 6324 to lisinopril. Evolving ECG LVH and BP lowering served as mediators. Incident symptomatic HF was the primary outcome. Linear regression (for mediator) and logistic regression (for outcome) models were adjusted for mediator‐outcome confounders (demographic and clinical characteristics known to be associated both with both LVH/hypertension and HF). A large majority of participants (96%) had ECG LVH status unchanged, but 4% developed evolving ECG LVH. On average, BP decreased by 11/7 mm Hg. In adjusted Cox regression analyses, progressing ECG LVH (hazard ratio [HR] 1.78 [95% CI 1.43‐2.22]), resolving ECG LVH (HR 1.33 [95% CI 1.03‐1.70]), and baseline ECG LVH (1.17 [95% CI 1.04‐1.31]) carried risk of incident HF. After full adjustment, evolving ECG LVH mediated 4% of the effect of doxazosin on HF. Systolic BP lowering mediated 12% of the effect of doxazosin, and diastolic BP lowering mediated 10% of the effect of doxazosin, 7% of the effect of amlodipine, and borderline 9% of the effect of lisinopril on HF.

Conclusions

Evolving ECG LVH and BP change account for 4% to 13% of the mechanism by which antihypertensive medications prevent HF.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000542.

See Editorial Ferdinand and Maraboto

OXY-SCORE: a new perspective for left ventricular hypertrophy diagnosis

Background:

A recently developed global indicator of oxidative stress (OXY-SCORE), by combining individual plasma biomarkers of oxidative damage and antioxidant capacity, has been validated in several pathologies, but not in left ventricular hypertrophy (LVH). The aim of this study was to design and calculate a plasma oxidative stress global index for patients with LVH.

Methods:

A total of 70 consecutive adult patients were recruited in our institution and assigned to one of the two study groups (control group/LVH group) by an echocardiography study. We evaluated plasmatic biomarkers of oxidative damage (malondialdehyde and thiolated proteins) and antioxidant defense (total thiols, reduced glutathione, total antioxidant capacity, catalase, and superoxide dismutase activities) by spectrophotometry/fluorimetry in order to calculate a plasma oxidative stress global index (OXY-SCORE) in relation to LVH.

Results:

The OXY-SCORE exhibited a highly significant difference between the groups (p < 0.001). The area under the receiver operating characteristic curve was 0.74 (95% confidence interval (CI), 0.62–0.85; p < 0.001). At a cut-off value of −1, the 68.6% sensitivity and 68.6% specificity values suggest that OXY-SCORE could be used to screen for LVH. A multivariable logistic regression model showed a positive association (p = 0.001) between OXY-SCORE and LVH [odds ratio = 0.55 (95% CI, 0.39–0.79)], independent of gender, age, smoking, glucose, systolic and diastolic arterial pressure, dyslipidemia, estimated glomerular filtration rate, body mass index, and valvular/coronary disease.

Conclusion:

OXY-SCORE could help in the diagnosis of LVH and could be used to monitor treatment response.

Hypertension-induced changes in the rat myocardium during the development of cardiac hypertrophy - a comparison between the left and the right ventricle

The hypertrophy of the cardiac muscle is one of the most significant maladaptive mechanisms activated in response to increased workload. It is associated with histological and ultrastructural alterations, changes in the quantitative parameters and the expression of different enzymes. While the structural and functional consequences of systemic hypertension on the left ventricle have been well evaluated, the right ventricle has received less attention. The aim of the present study was to analyse and compare the changes in the left and right ventricle during the development of cardiac hypertrophy initiated by systemic hypertension in different age groups of spontaneously hypertensive rats. Therefore, we studied the histology and ultrastructure of the cells of the myocardium, evaluated the immunohistochemical expression of the enzyme neuronal nitric oxide synthase and conducted a quantitative analysis of several morphometric parameters. We used three groups of spontaneously hypertensive rats. For the quantitative analysis we also used three age groups of age- and weight-matched control animals (normotensive Wistar rats). In both ventricles, we described cardiomyocytic hypertrophy, focal myocytolysis and increased collagen deposition in the interstitial space. Our observations on the ultrastructural level were associated with changes in the cardiomyocytic nuclei, the arrangement, maturity and organisation of the myofibrils, the localisation and ultrastructure of the mitochondria, the development and maturity of the intercalated discs, as well as changes in the components of the interstitium. The immunohistochemical expression of neuronal nitric oxide synthase in the left ventricle was stronger than that in the right ventricle across all age groups. The comparative quantitative analysis revealed that changes in the studied morphometric parameters in the two ventricles occurred disproportionately. In conclusion, the present study characterised the development of cardiac hypertrophy in response to systemic hypertension in both ventricles and demonstrated the involvement of the right ventricle.

Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis

BACKGROUND

Conditions of excess androgen in women, such as polycystic ovary syndrome (PCOS), often exhibit intergenerational transmission. One way in which the risk for PCOS may be increased in daughters of affected women is through exposure to elevated androgens in utero. Hyperandrogenemic conditions have serious health consequences, including increased risk for hypertension and cardiovascular disease. Recently, gut dysbiosis has been found to induce hypertension in rats, such that blood pressure can be normalized through fecal microbial transplant. Therefore, we hypothesized that the hypertension seen in PCOS has early origins in gut dysbiosis caused by in utero exposure to excess androgen. We investigated this hypothesis with a model of prenatal androgen (PNA) exposure and maternal hyperandrogenemia by single-injection of testosterone cypionate or sesame oil vehicle (VEH) to pregnant dams in late gestation. We then completed a gut microbiota and cardiometabolic profile of the adult female offspring.

RESULTS

The metabolic assessment revealed that adult PNA rats had increased body weight and increased mRNA expression of adipokines: adipocyte binding protein 2, adiponectin, and leptin in inguinal white adipose tissue. Radiotelemetry analysis revealed hypertension with decreased heart rate in PNA animals. The fecal microbiota profile of PNA animals contained higher relative abundance of bacteria associated with steroid hormone synthesis, Nocardiaceae and Clostridiaceae, and lower abundance of Akkermansia, Bacteroides, Lactobacillus, Clostridium. The PNA animals also had an increased relative abundance of bacteria associated with biosynthesis and elongation of unsaturated short chain fatty acids (SCFAs).

CONCLUSIONS

We found that prenatal exposure to excess androgen negatively impacted cardiovascular function by increasing systolic and diastolic blood pressure and decreasing heart rate. Prenatal androgen was also associated with gut microbial dysbiosis and altered abundance of bacteria involved in metabolite production of short chain fatty acids. These results suggest that early-life exposure to hyperandrogenemia in daughters of women with PCOS may lead to long-term alterations in gut microbiota and cardiometabolic function.

Prognostic Application of Thoracic Aortic Calcium Scoring for Adverse Clinical Outcome Risk in Elderly Patients with Left Ventricular Hypertrophy

Background and Objectives

Left ventricular hypertrophy (LVH) is associated with poor cardiovascular outcomes. Heavy aortic calcification exacerbates arterial stiffness, which consequently heightens left ventricular (LV) afterload. We assessed the usefulness of aortic calcification for predicting adverse cardiovascular outcomes and to determine whether the relationship, if any, differed as a function of LVH.

Methods

The analytic sample was comprised of a total of 487 individuals 65 years of age or older. Thoracic aorta calcium score (TACS) was measured by coronary computed tomography, and patients were stratified according to the median (TACS, 446 mm³). LVH obtained from echocardiography was defined as LV mass index >115 g/m² for men and >95 g/m² for women. Cox regression reporting hazard ratios (HRs) with 95% confidence intervals (CIs) was performed to predict the risk for the composite study endpoint, defined as cardiac death, admission for heart failure, obstructive coronary artery disease (CAD) requiring revascularization, or stroke.

Results

A total of 39 composite events (8.0%) occurred during a median follow-up of 65 months (interquartile range [IQR], 17–89 months). For those with LVH, the concurrent presence of high TACS appeared to be an independent predictor (HR, 4.51; 95% CI, 1.71–11.88; p=0.002) for the composite study endpoint. Other combined LVH and TACS subgroups were not associated with significant factors for predicting the composite study endpoint (p>0.050, all).

Conclusion

TACS provides robust predictive utility for a composite of cardiovascular events and cardiac death in persons with LVH. This finding was less pronounced in those with a relatively healthy myocardium, defined by the absence of LVH.

Prolylcarboxypeptidase deficiency is associated with increased blood pressure, glomerular lesions, and cardiac dysfunction independent of altered circulating and cardiac angiotensin II

Prolylcarboxypeptidase (PRCP) is a carboxypeptidase that cleaves angiotensin II (AngII) forming Ang(1-7). The impact of genetic PRCP deficiency on AngII metabolism, blood pressure (BP), kidney histology, and cardiac phenotype was investigated in two lines of PRCP-deficient mice: KST302 derived in C57BL/6 background and GST090 derived in FVB/N background. The GST090 line had increased mean arterial pressure (MAP) (113.7 ± 2.07 vs. WT 105.0 ± 1.23 mmHg; p < 0.01) and left ventricular hypertrophy (LVH) (ratio of diastolic left ventricular posterior wall dimension to left ventricular diameter 0.239 ± 0.0163 vs. WT 0.193 ± 0.0049; p < 0.05). Mice in the KST302 line also had mild hypertension and LVH. Cardiac defects, increased glomerular size, and glomerular mesangial expansion were also observed. After infusion of AngII to mice in the KST302 line, both MAP and LVH increased, but the constitutive differences between the gene trap mice and controls were no longer observed. Plasma and cardiac AngII and Ang(1-7) were not significantly different between PRCP-deficient mice and controls. Thus, PRCP deficiency is associated with elevated blood pressure and cardiac alterations including LVH and cardiac defects independently of systemic or cardiac AngII and Ang(1-7). An ex vivo assay showed that recombinant PRCP, unlike recombinant ACE2, did not degrade AngII to form Ang(1-7) in plasma at pH 7.4. PRCP was localized in α-intercalated cells of the kidney collecting tubule. The low pH prevailing at this site and the acidic pH preference of PRCP suggest a role of this enzyme in regulating AngII degradation in the collecting tubule where this peptide increases sodium reabsorption and therfore BP. However, there are other potential mechanisms for increased BP in this model that need to be considered as well. PRCP converts AngII to Ang(1-7) but only at an acidic pH. Global PRCP deficiency causes heart and kidney alterations and a moderate rise in BP. PRCP is abundant in the kidney collecting tubules, where the prevailing pH is low. In collecting tubules, PRCP deficiency could result in impaired AngII degradation. Increased AngII at this nephron site stimulates Na reabsorption and increases BP.

KEY MESSAGE

Prolylcarboxypeptidase (PRCP) converts AngII to Ang (1-7) but only at an acidic pH. Global PRCP deficiency causes heart and kidney alterations and a moderate rise in BP. PRCP is abundant in the kidney collecting tubules, where the prevailing pH is low. In collecting tubules, PRCP deficiency could result in impaired AngII degradation. Increased AngII at this nephron site stimulates Na reabsorption and increases BP.

Myocardial Hypertrophic Preconditioning Attenuates Cardiomyocyte Hypertrophy and Slows Progression to Heart Failure Through Upregulation of S100A8/A9

BACKGROUND

Transient preceding brief ischemia provides potent cardioprotection against subsequent long ischemia, termed ischemic preconditioning. Here, we hypothesized that transient short-term hypertrophic stimulation would induce the expression of hypertrophy regression genes and render the heart resistant to subsequent hypertrophic stress, and slow the progression to heart failure, as well.

METHODS AND RESULTS

Cardiomyocyte hypertrophy was induced in mice by either transverse aortic constriction or an infusion of phenylephrine, and in neonatal rat ventricular cardiomyocytes by norepinephrine exposures. In the preconditioning groups, hypertrophic stimulation was provided for 1 to 7 days and then withdrawn for several days by either aortic debanding or discontinuing phenylephrine or norepinephrine treatment, followed by subsequent reexposure to the hypertrophic stimulus for the same period as in the control group. One or 6 weeks after transverse aortic constriction, the heart weight/body weight ratio was lower in the preconditioning group than in the control group, whereas the lung weight/body weight ratio was significantly decreased 6 weeks after transverse aortic constriction. Similar results were obtained in mice receiving phenylephrine infusion and neonatal rat ventricular cardiomyocytes stimulated with norepinephrine. Both mRNA and protein expression of S100A8 and S100A9 showed significant upregulation after the removal of hypertrophic stimulation and persisted for 6 weeks in response to reimposition of transverse aortic constriction. The treatment with recombinant S100A8/A9 inhibited norepinephrine-induced myocyte hypertrophy and reduced the expression of calcineurin and NFATc3, but the silencing of S100A8/A9 prevented such changes.

CONCLUSIONS

Preconditioning with prohypertrophic factors exerts an antihypertrophic effect and slows the progression of heart failure, indicating the existence of the phenomenon for hypertrophic preconditioning.

A systematic review concerning the relation between the sympathetic nervous system and heart failure with preserved left ventricular ejection fraction

BACKGROUND

Heart failure with preserved left ventricular ejection fraction (HFPEF) affects about half of all patients diagnosed with heart failure. The pathophysiological aspect of this complex disease state has been extensively explored, yet it is still not fully understood. Since the sympathetic nervous system is related to the development of systolic HF, we hypothesized that an increased sympathetic nerve activation (SNA) is also related to the development of HFPEF. This review summarizes the available literature regarding the relation between HFPEF and SNA.

METHODS AND RESULTS

Electronic databases and reference lists through April 2014 were searched resulting in 7722 unique articles. Three authors independently evaluated citation titles and abstracts, resulting in 77 articles reporting about the role of the sympathetic nervous system and HFPEF. Of these 77 articles, 15 were included for critical appraisal: 6 animal and 9 human studies. Based on the critical appraisal, we selected 9 articles (3 animal, 6 human) for further analysis. In all the animal studies, isoproterenol was administered to mimic an increased sympathetic activity. In human studies, different modalities for assessment of sympathetic activity were used. The studies selected for further evaluation reported a clear relation between HFPEF and SNA.

CONCLUSION

Current literature confirms a relation between increased SNA and HFPEF. However, current literature is not able to distinguish whether enhanced SNA results in HFPEF, or HFPEF results in enhanced SNA. The most likely setting is a vicious circle in which HFPEF and SNA sustain each other.

Alterations in cardiac structure and function in hypertension

Hypertension is a powerful risk factor for cardiovascular mortality and morbidity, including heart failure with both preserved and reduced ejection fraction. Hypertensive heart disease (HHD) defines the complex and diverse perturbations of cardiac structure and function occurring secondary to hypertension. Left ventricular hypertrophy (LVH) is one of the most recognized features of HHD and is an established risk factor for adverse cardiovascular (CV) outcomes in hypertension. Beyond LVH, LV geometry provides additional information regarding the cardiac response to hypertension. Imaging studies from larger cohorts of hypertensive patients reveal wide variability in the prevalence of LVH and LV geometric patterns, with the prevalence of concentric LVH similar to that of eccentric LVH. Hypertension is also associated with concomitant impairments in LV diastolic and systolic function. It remains uncertain why patients develop different patterns of LVH, although demographics and clinical comorbidities appear to influence that response.

TRPC1, CaN and NFATC3 signaling pathway in the pathogenesis and progression of left ventricular hypertrophy in spontaneously hypertensive rats

Spontaneously hypertensive rats (SHR) was used to study left ventricular hypertrophy (LVH) and its dynamic change after the interventions with Telmisartan and Amlodipine. The results showed that the expression of TRPC1, CaN and NFATC3 increased gradually with the pathogenesis and progression of LVH. Telmisartan reduced blood pressure and LVH, and down-regulated the expression of TRPC1, CaN and NFATC3 in left ventricle of SHR. Amlodipine reduced the blood pressure in SHR but had no impact on the hypertrophy and expression of above factors. Our data suggest that the pathogenesis and progression of LVH in SHR are related to upregulation of TRPC1, CaN and NFATC3 signaling pathway.

Bilirubin Level is Associated with Left Ventricular Hypertrophy Independent of Blood Pressure in Previously Untreated Hypertensive Patients

Background and Objectives

Left ventricular hypertrophy (LVH), a sign of subclinical cardiovascular disease, is an important predictor of cardiovascular morbidity and mortality. The aim of our study was to determine the association of left ventricular mass (LVM) with possible causative anthropometric and biochemical parameters as well as carotid intima-media thickness (CIMT) and brachial flow-mediated dilation (FMD) as surrogates of atherosclerosis and endothelial dysfunction, respectively, in previously untreated hypertensive patients.

Subjects and Methods

Our study included 114 consecutive previously untreated hypertensive patients who underwent echocardiography and ultrasonography to evaluate their vascular status and function via brachial artery CIMT and FMD.

Results

Among all study parameters, age, systolic blood pressure (BP), diastolic BP, pulse pressure, plasma glucose, uric acid, total bilirubin, direct bilirubin, hemoglobin, and CIMT were positively correlated with the LVM index. Multiple logistic regression analysis revealed that office systolic BP, age, male gender, and total bilirubin were independent predictors of LVH.

Conclusion

Bilirubin seems to be related to LVM and LVH. The positive association of bilirubin with these parameters is novel and requires further research.

The JAK-STAT pathway in hypertrophic stress signaling and genomic stress response

The JAK-STAT signaling pathway plays a central role in transducing stress and growth signals in the hypertrophic heart. Unlike most signal transducers, JAKs and STATs signal in a number of different ways, both within the JAK-STAT pathway and in collaboration with other signaling pathways. In this review, we discuss how IL-6 activates cells lacking IL-6 receptors through trans-signaling and examine JAK-STAT pathway interaction with GPCR-linked pathways both within and between cells. Finally, we discuss recent studies showing how the JAK-STAT pathway can intersect with a general transcriptional regulatory mechanism to effect transcription of STAT-dependent stress response genes.

Salt-induced changes in cardiac phosphoproteome in a rat model of chronic renal failure

Heart damage is widely present in patients with chronic kidney disease. Salt diet is the most important environmental factor affecting development of chronic renal failure and cardiovascular diseases. The proteins involved in chronic kidney disease -induced heart damage, especially their posttranslational modifications, remain largely unknown to date. Sprague-Dawley rats underwent 5/6 nephrectomy (chronic renal failure model) or sham operation were treated for 2 weeks with a normal-(0.4% NaCl), or high-salt (4% NaCl) diet. We employed TiO₂ enrichment, iTRAQ labeling and liquid-chromatography tandem mass spectrometry strategy for phosphoproteomic profiling of left ventricular free walls in these animals. A total of 1724 unique phosphopeptides representing 2551 non-redundant phosphorylation sites corresponding to 763 phosphoproteins were identified. During normal salt feeding, 89 (54%) phosphopeptides upregulated and 76 (46%) phosphopeptides downregulated in chronic renal failure rats relative to sham rats. In chronic renal failure rats, high salt intake induced upregulation of 84 (49%) phosphopeptides and downregulation of 88 (51%) phosphopeptides. Database searches revealed that most of the identified phospholproteins were important signaling molecules such as protein kinases, receptors and phosphatases. These phospholproteins were involved in energy metabolism, cell communication, cell differentiation, cell death and other biological processes. The Search Tool for the Retrieval of Interacting Genes analysis revealed functional links among 15 significantly regulated phosphoproteins in chronic renal failure rats compared to sham group, and 23 altered phosphoproteins induced by high salt intake. The altered phosphorylation levels of two proteins involved in heart damage, lamin A and phospholamban were validated. Expression of the downstream genes of these two proteins, desmin and SERCA2a, were also analyzed.

Left ventricular remodelling in aortic stenosis

Aortic stenosis (AS) is a progressive condition associated with high mortality if not treated. The hemodynamic effects of AS have serious implications for the left ventricle. In this review, we describe the responses of the left ventricle to AS by highlighting the process of adaptive remodelling, which begins as a beneficial compensatory mechanism but ultimately transitions to a maladaptive process with potentially irreversible consequences. We discuss the impact of left ventricular (LV) remodelling on diastolic and systolic function and on the development of symptoms. In addition, we review the adverse consequences of maladaptive LV remodelling on clinical outcomes before and after aortic valve replacement. The relative irreversibility of maladaptive remodelling and the clear relationship between its progression and clinical outcomes suggest a need to incorporate measures of LV performance beyond simply systolic function when deciding on the timing of valve replacement.

The ameliorating effects of long-term electroacupuncture on cardiovascular remodeling in spontaneously hypertensive rats

Background

The purpose of this study was to investigate the inhibitory effects of long-term electroacupuncture at BaiHui (DU20) and ZuSanLi (ST36) on cardiovascular remodeling in spontaneously hypertensive rats (SHR) and underlying mechanisms.

Methods

6-weeks-old SHR or Wistar male rats were randomly, divided into 6 groups: the control group (SHR/Wistar), the non-acupoint electroacupuncture stimulation group (SHR-NAP/Wistar-NAP) and the electroacupuncture stimulation at DU20 and ST36 group (SHR-AP/Wistar-AP), 24 rats in each group. Rats were treated with or without electroacupuncture at DU20 and ST36, once every other day for a period of 8 weeks. The mean arterial pressure (MAP) was measured once every 2 weeks. By the end of the 8th week, the left ventricular structure and function were assessed by echocardiography. The content of angiotensin II (Ang II), endothelin-1 (ET-1) and nitric oxide (NO) in the plasma was determined using enzyme-linked immunosorbent assay. Histological studies on the heart and the ascending aorta were performed. The expression of angiotensin II type 1 receptor (AT1R), endothelin-1 type A receptor (ETAR), eNOS and iNOS in rat myocardium and ascending aorta was investigated by Western blotting.

Results

The MAP in SHR increased linearly over the observation period and significantly reduced following electroacupuncture as compared with sham control SHR rats, while no difference in MAP was observed in Wistar rats between electroacupuncture and sham control. The aortic wall thickness, cardiac hypertrophy and increased collagen level in SHR were attenuated by long term electroacupuncture. The content of Ang II, ET-1 in the plasma decreased, but the content of NO increased after electroacupuncture stimulation in SHR. Long term electroacupuncture significantly inhibited the expression of AT1R, ETAR and iNOS, whereas increased eNOS expression, in myocardium and ascending aorta of SHR.

Conclusions

The long term electroacupuncture stimulation at DU20 and ST36 relieves the increased MAP and cardiovascular abnormality in both structure and function in SHR, this beneficial action is most likely mediated via modulation of AT1R-AT1R-ET-1-ETAR and NOS/NO pathway.

Growth differentiation factor (GDF)-15 blocks norepinephrine-induced myocardial hypertrophy via a novel pathway involving inhibition of epidermal growth factor receptor transactivation

Accumulating evidence suggests that growth differentiation factor 15 (GDF-15) is associated with the severity and prognosis of various cardiovascular diseases. However, the effect of GDF-15 on the regulation of cardiac remodeling is still poorly understood. In this present study, we demonstrate that GDF-15 blocks norepinephrine (NE)-induced myocardial hypertrophy through a novel pathway involving inhibition of EGFR transactivation. Both in vivo and in vitro assay indicate that NE was able to stimulate the synthesis of GDF-15. The up-regulation of GDF-15 feedback inhibits NE-induced myocardial hypertrophy, including quantitation of [(3)H]leucine incorporation, protein/DNA ratio, cell surface area, and ANP mRNA level. Further research shows that GDF-15 could inhibit the phosphorylation of EGF receptor and downstream kinases (AKT and ERK1/2) induced by NE. Clinical research also shows that serum GDF-15 levels in hypertensive patients were significant higher than in healthy volunteers and were positively correlated with the thickness of the posterior wall of the left ventricle, interventricular septum, and left ventricular mass, as well as the serum level of norepinephrine. In conclusion, NE induces myocardial hypertrophy and up-regulates GDF-15, and this up-regulation of GDF-15 negatively regulates NE-induced myocardial hypertrophy by inhibiting EGF receptor transactivation following NE stimulation.

Evolution of cardiac and renal impairment detected by high-field cardiovascular magnetic resonance in mice with renal artery stenosis

BACKGROUND

Renal artery stenosis (RAS) promotes hypertension and cardiac dysfunction. The 2-kidney, 1-clip mouse model in many ways resembles RAS in humans and is amenable for genetic manipulation, but difficult to evaluate noninvasively. We hypothesized that cardiovascular magnetic resonance (CMR) is capable of detecting progressive cardiac and renal dysfunction in mice with RAS and monitoring the progression of the disease longitudinally.

METHODS

RAS was induced at baseline in eighteen mice by constricting the renal artery. Nine additional animals served as normal controls. CMR scans (16.4 T) were performed in all mice one week before and 2 and 4 weeks after baseline. Renal volumes and hemodynamics were assessed using 3D fast imaging with steady-state precession and arterial spin labelling, and cardiac function using CMR cine. Renal hypoxia was investigated using blood oxygen-level dependent (BOLD) MR.

RESULTS

Two weeks after surgery, mean arterial pressure was elevated in RAS mice. The stenotic kidney (STK) showed atrophy, while the contra-lateral kidney (CLK) showed hypertrophy. Renal blood flow (RBF) and cortical oxygenation level declined in the STK but remained unchanged in CLK. Moreover, cardiac end-diastolic and stroke volumes decreased and myocardial mass increased. At 4 weeks, STK RBF remained declined and the STK cortex and medulla showed development of hypoxia. Additionally, BOLD detected a mild hypoxia in CLK cortex. Cardiac end-diastolic and stroke volumes remained reduced and left ventricular hypertrophy worsened. Left ventricular filling velocities (E/A) indicated progression of cardiac dysfunction towards restrictive filling.

CONCLUSIONS

CMR detected longitudinal progression of cardiac and renal dysfunction in 2K, 1C mice. These observations support the use of high-field CMR to obtain useful information regarding chronic cardiac and renal dysfunction in small animals.

Features of left ventricular hypertrophy in patients with metabolic syndrome with or without comparable blood pressure: a meta-analysis

The prevalence of metabolic syndrome (MS) has been on the rise over the past few decades, and this is associated with an increased incidence of target organ damage such as left ventricular hypertrophy (LVH). This meta-analysis aims to evaluate the features of LVH in MS patients with or without high blood pressure (BP). PubMed, Cochrane Library, Embase, Science Citation Index, and China Biology Medicine Disc, WanFang data, China National Knowledge Infrastructure database, and VIP were searched. Cross-sectional studies which directly compared LVH in hypertensive patients with MS and those with hypertension alone were identified. The following parameters were analyzed: systolic blood pressure (SBP), diastolic blood pressure (DBP), left ventricular mass (LVM), left ventricular mass index (LVMI), left ventricular mass/height(2.7) (LVM/h(2.7)), interventricular septum thickness (IVSt), left ventricular end-diastolic diameter (LVEDd), left ventricular posterior wall (LVPW), ratio of early to late diastolic peak flow velocity (E/A), and relative wall thickness (RWT). Data were extracted and analyzed by Cochrane Collaboration's RevMan 5.0 software. 14 studies involving 5,994 patients were included. In four studies, MS patients with comparable level of BP had higher SBP (mmHg) [Mean Difference (MD) = 2.28, 95 % confidence intervals (CI): -0.58 to 5.13], DBP (mmHg) (MD = 1.32, 95 % CI: -0.23 to 2.87), LVM (g) (MD = 42.10, 95 % CI: 6.92-77.28), LVMI (g/m(2)) (MD = 8.93, 95 % CI: 5.29-12.57), LVM/h(2.7) (g/m(2.7)) (MD = 5.40, 95 % CI: 2.51-8.29), IVSt (mm) (MD = 0.49, 95 % CI: 0.28-0.71), LVEDd (mm) (MD = 1.04, 95 % CI: -1.10 to 3.18), LVPW (mm) (MD = 0.75, 95 % CI: 0.13-1.37), RWT (MD = 0.06, 95 % CI: -0.00 to 0.12), and lower E/A (MD = -0.08, 95 % CI: -0.18 to 0.02) when compared to the patients with hypertension alone. In other ten studies, the hypertensive patients with MS exhibited higher levels of SBP (mmHg) (MD = 4.67, 95 % CI: 2.72-6.62), DBP (mmHg) (MD = 2.03,95 % CI: 1.40-2.65), LVM (g) (MD = 24.79, 95 % CI: 20.21-29.36), LVMI(g/m(2)) (MD = 9.22, 95 % CI: 2.81-15.64), LVM/h(2.7) (g/m(2.7)) (MD = 5.97, 95 % CI: 4.14-7.80), IVSt (mm) (MD = 0.63, 95 % CI: 0.58-0.69), LVEDd (mm) (MD = 1.11, 95 % CI: 0.42-1.80), LVPW (mm) (MD = 0.63, 95 % CI: 0.31-0.94), RWT (MD = 0.02, 95 % CI: 0.01-0.03), as compared to patients with hypertension alone (P < 0.05). In addition, the MS patients combining with hypertension showed a lower E/A (MD = -0.07, 95 % CI: -0.10 to -0.04) when compared to those with hypertension alone. This study suggests that MS plays an important role in the development of LVH. MS seems to amplify hypertension-related cardiac changes. Furthermore, MS combining with higher level of BP will aggravate LVH and damage the diastolic function of left ventricle.

Severity of cardiomyopathy associated with adenine nucleotide translocator-1 deficiency correlates with mtDNA haplogroup

Mutations of both nuclear and mitochondrial DNA (mtDNA)-encoded mitochondrial proteins can cause cardiomyopathy associated with mitochondrial dysfunction. Hence, the cardiac phenotype of nuclear DNA mitochondrial mutations might be modulated by mtDNA variation. We studied a 13-generation Mennonite pedigree with autosomal recessive myopathy and cardiomyopathy due to an SLC25A4 frameshift null mutation (c.523delC, p.Q175RfsX38), which codes for the heart-muscle isoform of the adenine nucleotide translocator-1. Ten homozygous null (adenine nucleotide translocator-1(-/-)) patients monitored over a median of 6 years had a phenotype of progressive myocardial thickening, hyperalaninemia, lactic acidosis, exercise intolerance, and persistent adrenergic activation. Electrocardiography and echocardiography with velocity vector imaging revealed abnormal contractile mechanics, myocardial repolarization abnormalities, and impaired left ventricular relaxation. End-stage heart disease was characterized by massive, symmetric, concentric cardiac hypertrophy; widespread cardiomyocyte degeneration; overabundant and structurally abnormal mitochondria; extensive subendocardial interstitial fibrosis; and marked hypertrophy of arteriolar smooth muscle. Substantial variability in the progression and severity of heart disease segregated with maternal lineage, and sequencing of mtDNA from five maternal lineages revealed two major European haplogroups, U and H. Patients with the haplogroup U mtDNAs had more rapid and severe cardiomyopathy than those with haplogroup H.