Salusins: potential use as a biomarker for atherosclerotic cardiovascular diseases

Investigation of the relationship between diastolic notching in uterine artery Doppler and serum salusin alpha and beta concentrations in the first trimester

OBJECTIVE

Studies have shown that members of the salusin family regulate the migration and proliferation of arterial smooth muscle cells and increase the tendency to atherosclerosis through fibrosis and calcification in the vascular wall. However, the effect of salusins on the uterine artery has not yet been investigated. This study was conducted to investigate whether serum salusin alpha and beta concentrations in the first trimester are associated with diastolic notching in uterine artery Doppler.

METHODS

This non-interventional cohort study was conducted on 88 pregnant women, 44 of whom had diastolic notching on unilateral or bilateral uterine artery Doppler, and 44 of whom did not have diastolic notching on uterine artery Doppler. The uterine artery notch positive and negative groups were compared in terms of serum salusin alpha and beta concentrations.

RESULTS

The two groups were similar in terms of demographic characteristics (p < 0.05). The median salusin alpha concentration was found to be 689.4 pg/ml in the uterine artery notch positive group, while it was 734.6 pg/ml in the uterine artery notch negative group (p = 0.608). The median salusin beta concentration was found to be 674.5 pg/ml in the uterine artery notch positive group, while it was 693.8 pg/ml in the uterine artery notch negative group (p = 0.453).Participants were regrouped into normal and high uterine artery resistance and compared in terms of serum salusin alpha and beta concentrations. The median salusin alpha concentration was found to be 994.5 pg/ml in the high uterine artery PI group, while it was 685.2 pg/ml in the normal uterine artery PI group (p = 0.698). The median salusin beta concentration was found to be 1,100.8 pg/ml in the high uterine artery PI group, while it was 669.1 pg/ml in the normal uterine artery PI group (p = 0.584).

CONCLUSION

Although the sample size was too small to draw a definitive conclusion, our results indicate that uterine artery diastolic notching or increased resistance in the uterine artery does not appear to be associated with serum salusin alpha or beta concentrations.

Evaluation of serum salusin-α and β levels in patients with obstructive sleep apnea

Aim: Salusin-α and salusin-β peptides are crucial in the development of cardiovascular diseases like coronary artery disease (CAD). This study compared serum levels of these peptides in patients with obstructive sleep apnea (OSA), those with both OSA and CAD. Materials & methods: Patients without OSA were included in Group 1, those with OSA alone comprised Group 2, and those with OSA and CAD were in Group 3. Results: Salusin-α level was significantly higher in controls than in Groups 2 and 3, while salusin-β levels were significantly higher in Groups 2 and 3 compared with the control group. Conclusion: Salusin-α and -β levels may be parameters that can guide the diagnosis of OSA in patients with a consistent clinical history.

The relationship of salusins with Parkinson's Disease, Alzheimer's Disease, and acute ischemic stroke: A preliminary study

Neuroinflammation, oxidative stress, and apoptosis play important roles in the pathophysiology of Alzheimer's Disease (AD), Parkinson's Disease (PD), and Acute Ischemic Stroke (AIS). Salusin-α and salusin-β peptides, which were shown to be present in many tissues, including the central nervous system, were also shown to be associated with apoptosis, inflammation, and oxidative stress. In the present study, the relationship between Salusin-α and salusin-β peptides and AD, PD, and AIS were investigated. A total of 179 people were included in the present study, including 46 AD, 44 PD, 42 AIS, and 47 controls. Plasma Salusin-α and salusin-β levels were measured with the ELISA Method. The plasma salusin-β levels of AD, PD, and AIS patients were lower than the control group at significant levels (p < 0.05). It was also found that there were correlations between salusin-α and salusin-β levels and age, triglyceride, LDL-c, total cholesterol, and hemoglobin levels. In this study, we found that salusin- β, an endogenous neuropeptide, was associated with AD, PD and AIS. The low level of salusin-β in these diseases in which neuronal damage occurs may be related to the neuroprotective properties of this endogenous peptide. Further studies are needed to fully understand the relationship between salusin-β and the pathophysiology of these diseases.

Serum salusin-β levels in patients with systemic lupus erythematosus

OBJECTIVE

Endothelial dysfunction (ED) has an important role in the pathogenesis of systemic lupus erythematosus (SLE). Studies on other inflammatory diseases show that salusin-β with various mechanisms may play a role in the promotion of ED and inflammation. The aim of this study was to measure serum salusin-β levels in SLE patients and evaluate it as a potential biomarker in assessing SLE activity and predicting organ involvement.

METHODS

In a cross-sectional study, 60 patients diagnosed with SLE and 30 age- and sex-matched healthy controls were enrolled. Disease activity of SLE patients was assessed by the systemic lupus erythematosus disease activity index 2000 (SLEDAI-2 K). Serum levels of salusin-ß were measured using a human salusin-ß enzyme-linked immunosorbent assay kit.

RESULTS

Serum salusin-β levels in SLE and control groups were 474.2 ± 117.1 pg/ml and 157.7 ± 88.7 pg/ml, respectively. The difference was significant (P = 0.001). There was no significant correlation between serum salusin-β levels with age (r =  - 0.06, P = 0.632) and SLEDAI (r =  - 0.185, P = 0.158). In patients with nephritis and thrombosis, serum salusin-β was significantly higher. In addition, in patients with serositis, serum salusin-β was significantly lower. Multiple linear regression analysis showed that serum salusin-β levels retained a significant association with nephritis and thrombosis after model adjustment for serositis, nephritis, and thrombosis.

CONCLUSIONS

Our findings showed that salusin-β might have a possible role in the pathogenesis of SLE. Salusin-β may be a potential biomarker for nephritis and thrombosis in SLE. Key Points • Serum salusin-β levels were significantly higher in SLE patients than the control group. • There was no significant correlation between serum salusin-β levels with age and SLEDAI. • Serum salusin-β levels retained a significant association with nephritis and thrombosis.

The Clinical Significance of Salusins in Systemic Sclerosis-A Cross-Sectional Study

Background: Systemic sclerosis (SSc) is a connective tissue disease manifesting with progressive fibrosis of the skin and internal organs. Its pathogenesis is strictly associated with vascular disfunction and damage. Salusin-α and salusin-β, endogenous peptides regulating secretion of pro-inflammatory cytokines and vascular smooth muscle proliferation, may potentially play a role in SSc pathogenesis. Objectives: The aim of this study was to assess the concentration of salusins in sera of patients with SSc and healthy controls and to evaluate correlations between the salusins levels and selected clinical parameters within the study group. Materials and methods: 48 patients with SSc (44 women; mean age, 56.4, standard deviation, 11.4) and 25 adult healthy volunteers (25 women; mean age, 55.2, standard deviation, 11.2) were enrolled. All patients with SSc were treated with vasodilators and twenty-seven of them (56%) also received immunosuppressive therapy. Results: Circulating salusin-α was significantly elevated in patients with SSc in comparison to healthy controls (U = 350.5, p = 0.004). Patients with SSc receiving immunosuppression had higher serum salusin-α concentrations compared with those without immunosuppressive therapy (U = 176.0, p = 0.026). No correlation was observed between salusins concentrations and skin or internal organ involvement parameters. Conclusions: Salusin-α, a bioactive peptide mitigating the endothelial disfunction, was elevated in patients with systemic sclerosis receiving vasodilators and immunosuppressants. Increased salusin-α concertation may be associated with the initiation of atheroprotective processes in patients with SSc managed pharmacologically, which requires verification in future studies.

Serum salusin-α and salusin-β levels in patients with psoriatic arthritis

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by skin lesions and joint involvement. Salusin-α and salusin-β are two new bioactive molecules. It is reported that salusins may have role in regulation of the immune system and inflammation. The aim of our study was to evaluate the serum salusin-α and salusin-β levels in PsA patients and to establish the possible relationship with the disease features.

MATERIAL AND METHODS

Our study included 40 PsA patients who fulfilled the CASPAR criteria and 40 healthy volunteers. Demographic, clinical, laboratory and radiological data and disease activity indices (PASI, BASDAI, BASFI, HAQ) were recorded in all patients. The enzyme-linked immunosorbent assay (ELISA) method was used to measure serum salusin-α and salusin-β levels.

RESULTS

The demographic data were as follows: 13 patients (32.5%) were males and 27 (67.5%) were female, mean age was 48.5 years and mean disease duration was 2.4 years. Patients' history was taken and clinical assessment was performed; 20 (50%) patients had a family history, 18 (45%) patients were smoker, 19 (47.5%) patients had HLA-B27 positivity, 33 (82.5%) had sacroiliitis, 36 (90%) had enthesitis, 23 (57.5%) had distal interphalangeal (DIP) joint and nail involvement, 26 (65%) had wrist involvement, and 11 (27.5%) had ankle involvement. Laboratory data of the patients were recorded; 20 (50%) patients had elevated CRP level and 25 (62.5%) patients had an elevated ESR level. The study results showed that PsA patients had an elevated serum salusin-α level when compared with the control group (p = 0.004). The association between serum salusin-α level and ankle arthritis was found (p = 0.04). Serum levels of salusin-β were similar in PsA patients and controls both (p = 0.285).

CONCLUSIONS

We found elevated serum salusin-α in PsA patients while the serum salusin-β levels were normal. Salusin-α may have a possible role in disease pathogenesis and it may be use as a reliable biomarker in PsA patients. Multicenter prospective studies are needed in this regard.

Saluisn-β contributes to endothelial dysfunction in monocrotaline-induced pulmonary arterial hypertensive rats

BACKGROUND

The endothelial dysfunction and the consequent attenuated pulmonary vasodilatation are the major causes of elevated pulmonary arterial resistance and pressure in pulmonary arterial hypertension (PAH). Current study aimed to explore the effects of a TOR2A gene product, salusin-β, on endothelium-dependent vascular relaxation and the progression of PAH in monocrotaline (MCT)-induced PAH rats as well as the relevant signaling pathway.

METHODS

Acetylcholine (ACh)-induced dose-dependent relaxation was used to evaluate the endothelium-dependent vasodilatation function.

RESULTS

The salusin-β level in plasma and pulmonary artery (PA) in MCT-PAH rats were significantly increased, while the ACh-induced endothelium-dependent vasodilatation was attenuated. After salusin-β incubation or overexpression of salusin-β gene, the endothelium-dependent relaxation was further deteriorated, while anti-salusin-β IgG incubation or knockdown of salusin-β improved it in PAH rats. The superoxide anions scavenger NAC or the antioxidant apocynin inhibited the effect of salusin-β, while the SOD inhibitor DETC further enhanced it. The nitric oxide (NO) synthase inhibitor L-NAME almost blocked the effect of anti-salusin-β IgG. Silencing of salusin-β in PAH rats decreased right ventricular (RV) systolic pressure, RV hypertrophy index, NAD(P)H oxidase activity and ROS level, and increased the eNOS activity and NO level of PA. Overexpression of salusin-β played opposite roles.

CONCLUSIONS

The elevated saluisn-β level in PAH rats plays important roles in the reduction of endothelium-dependent vasodilatation and participates in the progression of PAH through stimulating NAD(P)H oxidase-ROS production and inhibiting eNOS-NO release.

Current Knowledge of Selected Cardiovascular Biomarkers in Pediatrics: Kidney Injury Molecule-1, Salusin-α and -β, Uromodulin, and Adropin

Cardiovascular diseases are the leading cause of morbidity and mortality in the modern world. Their common denominator is atherosclerosis, a process beginning in childhood. In pediatrics, the aim of preventive measures is to recognize children and adolescents at risk for accelerated atherosclerosis and possible premature cardiovascular events in adulthood. Several diagnostic procedures and biomarkers are available for cardiovascular risk assessment in adults. However, reliable markers in pediatrics are still insufficiently studied. In this contribution, we discuss five potential biomarkers of particular interest: kidney injury molecule-1, salusin-α and -β, uromodulin, and adropin. Studies regarding the pediatric population are scarce, but they support the evidence from studies in the adult population. These markers might entail both a prognostic and a therapeutic interest.

Salusin‑β participates in high glucose‑induced HK‑2 cell ferroptosis in a Nrf‑2‑dependent manner

Ferroptosis is critically involved in the pathophysiology of diabetic nephropathy (DN). As a bioactive peptide, salusin‑β is abundantly expressed in the kidneys. However, it is unclear whether salusin‑β participates in the pathologies of diabetic kidney damage by regulating ferroptosis. The present study found that high glucose (HG) treatment upregulated the protein expressions of salusin‑β in a dose‑ and time‑dependent manner. Genetic knockdown of salusin‑β retarded, whereas overexpression of salusin‑β aggravated, HG‑triggered iron overload, antioxidant capability reduction, massive reactive oxygen species production and lipid peroxidation in HK‑2 cells. Mechanistically, salusin‑β inactivated nuclear factor erythroid‑derived 2‑like 2 (Nrf‑2) signaling, thus contributing to HG‑induced ferroptosis‑related changes in HK‑2 cells. Notably, the protein expression of salusin‑β was upregulated by ferroptosis activators, such as erastin, RSL3, FIN56 and buthionine sulfoximine. Pretreatment with ferrostatin‑1 (a ferroptosis inhibitor) prevented the upregulated protein expression of salusin‑β in HK‑2 cells exposed to HG. Taken together, these results suggested that a positive feedback loop between salusin‑β and ferroptosis primes renal tubular cells for injury in diabetes.

Improvement of Vascular Function by Knockdown of Salusin-β in Hypertensive Rats via Nitric Oxide and Reactive Oxygen Species Signaling Pathway

Purpose

Salusin-β, a multifunctional vasoactive peptide, has a potentially important function in the pathological development of hypertension. However, the exact functional role of salusin-β and the underlying mechanism in this process are still not fully understood. The current study aimed to investigate the effects of silencing salusin-β on vascular function and vascular remodeling, as well as its signaling pathways in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY).

Methods

Silencing salusin-β was performed by caudal vein injection of adenovirus expressing salusin-β short hairpin RNA (shRNA). Acetylcholine (ACh)-induced endothelium-dependent relaxation was used to evaluate vasodilator function, and high K⁺ solution-induced constriction was used to evaluate vasoconstriction function.

Results

Salusin-β levels in plasma and its protein expression in mesenteric artery (MA), coronary artery (CA), and pulmonary artery (PA) of SHR were higher than those in WKY. The salusin-β level and expression were decreased effectively by salusin-β shRNA. Knockdown of salusin-β decreased arterial blood pressure (ABP) and high K⁺ solution-induced vascular constrictions, and improved the endothelium-dependent relaxation and vascular remodeling in SHR. The improved effect of silencing salusin-β on ACh-induced relaxation in SHR was almost blocked by the nitric oxide synthase (NOS) inhibitor L-NAME. Compared to WKY, the endothelial NOS (eNOS) activity and level, and nitric oxide (NO) level were decreased, while NAD(P)H oxidase activity and reactive oxygen species (ROS) levels in MA, CA, and PA of SHR were increased, which were all redressed by salusin-β knockdown.

Conclusion

These results indicate that knockdown of salusin-β improves endothelium-dependent vascular relaxation and vascular remodeling and decreases ABP and vasoconstriction in SHR, which might be accomplished by increasing eNOS activation and NO release while inhibiting NAD(P)H oxidase derived-ROS generation. Scavenging salusin-β improves vascular function and then prevents the development and progression of vasculopathy of hypertension.

The role of serum salusin alpha and beta levels and atherosclerotic risk factors in idiopathic sudden hearing loss pathogenesis

PURPOSE

The aim of this study was to investigate the importance of atherosclerosis in the pathogenesis of sudden hearing loss by evaluating the newly discovered markers, serum salusin-α and salusin-β. We also aimed to evaluate atherosclerosis risk factors, such as lipid profile, smoking, body mass index, waist circumference and mean blood pressure of the patients.

METHODS

Fifty-two patients diagnosed with sudden hearing loss (study group) and fifty healthy people (control group) were included in the study. Detailed history was taken from the patients and risk factors for atherosclerosis, such as smoking, body mass index, waist circumference, lipid profile, mean blood pressure and serum salusin-α and salusin-β levels, were evaluated. The study group was divided into recovery group (subgroup I) and non-recovery group (subgroup II).

RESULTS

The salusin-β median value was found to be significantly higher in the study group compared to the control group (p < 0.05). The salusin-β median value was found to be significantly higher in subgroup 2 and was found to be a poor prognostic factor (p < 0.05).

CONCLUSION

From the results obtained in this study, it is thought that salusin-β peptide is increased in patients with sudden hearing loss and it can be evaluated as a poor prognostic factor.

Effectiveness of Continuous Aerobic Versus High-Intensity Interval Training on Atherosclerotic and Inflammatory Markers in Boys With Overweight/Obesity

PURPOSE

Atherosclerosis is a complex multifactorial disease whose first steps can be initiated from childhood. Therefore, we examined the effects of 2 training models on salusins levels, inflammatory markers, and lipid profile in boys with overweight/obesity.

METHOD

Forty-five boys with overweight/obesity with the mean age of 11.06 (1.0) years were randomly divided into three groups of 15: a high-intensity interval training (HIIT) group (100%-110% of maximum aerobic speed); an aerobic training group (40%-70% of heart rate reserve); and a control group. The intervention included 3 sessions per week for 12 weeks.

RESULTS

Findings showed significant improvements in serum levels of salusins, salusins ratio, interleukin-6 (IL-6), and total cholesterol (TC) in both training groups (P < .001). Also, the serum levels of C-reactive protein (CRP), triglycerides (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), atherogenic index of plasma (AIP), and cholesterol index improved significantly (P < .01). Except for the TG, HIIT caused higher improvements than aerobic training (P < .001 for salusin-α, salusins ratio, IL-6, CRP, TC, HDL, AIP, and cholesterol index; and P < .01 for salusin-β and LDL).

CONCLUSION

The present study shows that HIIT has more positive effects than aerobic exercise on the atherosclerotic and inflammatory factors, as well as lipid profile variables in children with overweight/obesity.

Assessment of salusin alpha and salusin beta levels in patients with newly diagnosed dipper and non-dipper hypertension

OBJECTIVE

The pathophysiology of non-dipper hypertension has not been clarified. The relationship between salusins with atherosclerosis and hypertension has gained attention in recent years. The aim of this paper is to investigate whether salusins are associated with circadian blood pressure, left ventricular mass index, and diastolic functions in newly diagnosed hypertensives.

METHODS

The study included 88 newly diagnosed hypertensive individuals. Twenty-four-hour ambulatory blood pressure monitoring and echocardiographic examinations were performed. The patients were assigned to dipper hypertension (n = 41) and non-dipper hypertension (n = 47) groups based on the ambulatory blood pressure monitoring results according to the presence of ≥ a 10% decrease in nighttime blood pressure values or not. Serum salusin α and β levels were determined by electrochemiluminescence immunological test method.

RESULTS

Compared to dipper hypertension, non-dipper hypertension group demonstrated lower salusin α levels (1818.71 ± 221.67 vs 1963 ± 200.75 pg/mL, p = .002), mitral E/A, septal E'/A' and higher salusin β levels (576.24 ± 68.15 vs 516.13 ± 90.7 pg/ml, p = .001) and left ventricular mass index. Multivariate logistic regression analysis revealed salusin-α (OR 0.474, 95% CI 0.262 to 0.986, p = .001), salusin-β (OR 2.550, 95% CI 2.123 to 2.991, p = .018), and left ventricular mass index (OR 2.620, 95% CI 2.124 to 2.860, p = .011) as independent predictors of non-dipper hypertension. As candidate markers to predict non-dipper hypertension, decreased salusin α, and increased salusin β levels may mediate crosstalk between sympathetic and parasympathetic systems and indicate poor cardiovascular prognosis in hypertension.

Salusin- is superior to salusin- as a marker for evaluating coronary atherosclerosis

Objective

This study was performed to evaluate the interaction effect of salusin-α and salusin-β on coronary artery injury or stenosis.

Methods

The salusin-α and salusin-β concentrations were measured by enzyme-linked immunosorbent assay in 256 patients who underwent coronary angiography for chest pain, and coronary artery stenosis was assessed by the SYNTAX scoring system. Multivariate logistic regression was used to analyze the correlation between variables and coronary artery stenosis. The interaction of salusin-α and salusin-β on coronary artery stenosis was further explored by multiple linear regression.

Results

The model goodness of fit (R) for the interaction effect of salusin-α and salusin-β on coronary artery stenosis was 0.863, and the adjusted R value revealed that the interaction could explain 74.3% of the variation in SYNTAX scores. The F-statistic exceeded F_0.05 (3.031485935) and P < 0.001, further showing that salusin-α and salusin-β had a significant interaction effect on coronary artery stenosis. The standard coefficient for salusin-β (0.797) was higher than that for salusin-α (−0.367, indicating an inhibitory effect), showing that salusin-β had a greater effect on coronary artery stenosis.

Conclusions

Salusin-β, a potential marker for assessing coronary atherosclerosis, was superior to salusin-α, contributing to our understanding of the etiology of coronary artery stenosis.

Anti‑inflammatory effect of salusin‑β knockdown on LPS‑activated alveolar macrophages via NF‑κB inhibition and HO‑1 activation

Inflammation of alveolar macrophages is the primary pathological factor leading to acute lung injury (ALI), and NF-κB activation and HO-1 inhibition are widely involved in inflammation. Salusin-β has been reported to contribute to the progression of the inflammatory response, but whether salusin-β could regulate inflammation in lipopolysaccharide (LPS)-induced ALI remains unknown. The present study aimed to investigate the role of salusin-β in LPS-induced ALI and to uncover the potential underlying mechanisms. Sprague-Dawley rats were subjected to LPS administration, and then pathological manifestations of lung tissues, inflammatory cytokines levels in bronchoalveolar lavage fluid (BALF) and expression of salusin-β in macrophages of lung tissues were assessed. NR8383 cells with or without salusin-β knockdown were treated with LPS, and then the concentration of inflammatory cytokines, and the expression of high mobility group box-1 (HMGB1), NF-κB signaling molecules and heme oxygenase-1 (HO-1) levels were detected. The results showed that LPS caused injury of lung tissues, increased the levels of proinflammatory cytokines in BALF, and led to higher expression of salusin-β or macrophages in lung tissues of rats. In vitro experiments, LPS also upregulated salusin-β expression in NR8383 cells. Knockdown of salusin-β using short hairpin (sh)RNA inhibited the LPS-induced generation of inflammatory cytokines. LPS also enhanced HMGB1, phosphorylated (p)-IκB and p-p65 expression, but reduced HO-1 expression in both lung tissues and NR8383 cells, which were instead inhibited by the transfection of sh-salusin-β. In addition, knockdown of HO-1 using shRNA reversed the inhibitory effect of sh-salusin-β on the LPS-induced generation of inflammatory cytokines, activation of NF-κB signaling and inactivation of HO-1. In conclusion, this study suggested that knockdown of salusin-β may inhibit LPS-induced inflammation in alveolar macrophages by blocking NF-κB signaling and upregulating HO-1 expression.

Serum salusin-β in relation to atherosclerosis and ventricular dysfunction in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

Salusin-β is a newly defined biomarker that plays a role in atherogenesis and in homeostasis. The study aimed to assess serum salusin-β level in relation to atherosclerosis and ventricular dysfunction in type 2 diabetes mellitus (T2DM) patients.

METHODS

Sixty T2DM patients and twenty-five age-matched healthy controls were included. Serum salusin-β was determined by ELISA. Echocardiography and carotid ultrasonography were carried out for all individuals.

RESULTS

Serum salusin-β level was significantly elevated in patients with T2DM than in controls (P < 0.001). It was positively correlated with obesity parameters, insulin resistance index (r = 0.280,P < 0.001), atherogenic dyslipidemia and with carotid intima media thickness (CIMT) (r = 0.411, P < 0.001). Echocardiographic findings showed a positive correlation between salusin-β and left ventricular hypertrophy (LVH) parameters and a negative correlation with left ventricular (LV) diastolic and systolic functions. Regression analysis showed that serum salusin-β level was a significant predictor of diastolic dysfunction.

CONCLUSION

Serum salusin-β may be associated with atherosclerosis and LV dysfunction in T2DM.

Natriuretic Peptides as the Basis of Peptide Drug Discovery for Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading global cause of death, accounting for more than 17.6 million deaths per year in 2016, a number that is expected to grow to more than 23.6 million by 2030. While many technologies are currently under investigation to improve the therapeutic outcome of CVD complications, only a few medications have been approved. Therefore, new approaches to treat CVD are urgently required. Peptides regulate numerous physiological processes, mainly by binding to specific receptors and inducing a series of signals, neurotransmissions or the release of growth factors. Importantly, peptides have also been shown to play an important role in the circulatory system both in physiological and pathological conditions. Peptides, such as angiotensin II, endothelin, urotensin-II, urocortins, adrenomedullin and natriuretic peptides have been implicated in the control of vascular tone and blood pressure as well as in CVDs such as congestive heart failure, atherosclerosis, coronary artery disease, and pulmonary and systemic hypertension. Hence it is not surprising that peptides are becoming important therapeutic leads in CVDs. This article will review the current knowledge on peptides and their role in the circulatory system, focusing on the physiological roles of natriuretic peptides in the cardiovascular system and their implications in CVDs.

The importance of circulating levels of salusin-α, salusin-β, and heregulin-β1 in atherosclerotic coronary arterial disease

OBJECTIVE

The relationship between the severity of atherosclerotic coronary artery disease (CAD) and circulating levels of salusin-α, salusin-β and heregulin-β1 has been investigated. In addition, the relationship with these peptides and high sensitive C-reactive protein (hsCRP) has been investigated.

METHODS

The study was conducted on 55 volunteers who had normal coronary angiography (CAG) as the control group, 35 volunteers with the degree of coronary artery stenosis below 50% in CA as the non-critical stenosis group, 37 volunteers with narrowing of one coronary artery above 50% as single vessel group and 41 volunteers with narrowing of more than one coronary artery above 50% as multi-vessel group. One hundred and thirteen volunteers have been included to CAD group.

RESULTS

There was no statistically significant difference in serum salusin-α levels between groups. Serum salusin-β ve hsCRP levels were significantly lower in control group compared to other groups and CAD group. There was no statistically significant difference in salusin-β and salusin-α levels in reciprocal comparison of other groups other than heregulin-β1 levels. Heregulin-β1 levels were significantly lower in 'non-critical occlusion' and 'multiple artery occlusion' groups compared to control group. Heregulin-β1 levels in 'single artery occlusion' group were significantly higher than control, 'non-critical occlusion' and 'multiple artery occlusion' groups.

CONCLUSION

Salusin-α levels does not indicate any significant differences between any groups in our study however the relationship of salusin-α with salusin- β and heregulin-β1 levels drives to cogitate that these peptides can be used as biomarkers and therapeutic approaches in CAD. We think that these peptides will be used in laboratories routinely in future in addition to hsCRP for CAD.

A TOR2A Gene Product: Salusin-β Contributes to Attenuated Vasodilatation of Spontaneously Hypertensive Rats

PURPOSE

Attenuated vasodilatation of small arteries is a hallmark feature of hypertension. Salusin-β, which is a TOR2A gene product and an important vasoactive peptide, has a close relationship with cardiovascular disease. This study aimed to determinate the roles of salusin-β in vasodilatation, and its signal pathways in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR).

METHODS

Isometric tension experiments were performed. Vasodilatation was induced by acetylcholine (ACh) or sodium nitroprusside (SNP).

RESULTS

Plasma salusin-β levels and their protein expressions in coronary artery (CA), mesenteric artery (MA), and pulmonary artery (PA) of SHR were much higher than that of WKY. Intravenous injection of salusin-β increased arterial blood pressure in SHR, while anti-salusin-β IgG decreased it. Salusin-β further deteriorated, while anti-salusin-β IgG improved, the attenuated ACh-induced relaxation, the decreased nitric oxide (NO) level, and endothelial nitric oxide synthase (eNOS) activity in arteries of SHR, and salusin-β had no significant effect on SNP-induced relaxation. The NAD(P)H oxidase activity and reactive oxygen species (ROS) level in arteries of SHR were much higher than that of WKY, which was further increased by salusin-β but reduced by anti-salusin-β IgG. ROS scavenger NAC or antioxidant apocynin significantly inhibited, while SOD inhibitor DETC aggravated, the effects of salusin-β, and the eNOS inhibitor L-NAME inhibited the effects of anti-salusin-β IgG.

CONCLUSIONS

These results indicated that enhanced salusin-β activity is involved in attenuated endothelium-dependent vasodilatation pathogenesis in SHR by activating NAD(P)H oxidase derived ROS generation and inhibiting eNOS activation and NO release.

Increased serum salusin-α by aerobic exercise training correlates with improvements in arterial stiffness in middle-aged and older adults

Aging causes arterial stiffening which can be mitigated by increased physical activity. Although low circulating levels of salusin-α are associated with cardiovascular disease, whether salusin-α decreases with aging and whether the reduced arterial stiffening occurring with exercise training is associated with increased serum salusin-α is unknown. Herein we assessed carotid-femoral pulse wave velocity (cfPWV), systolic (SBP) and diastolic (DBP) blood pressures in a cross-sectional study that compared young (20-39-year-old, n=45) versus middle-aged and older (40-80-year-old, n=60) subjects. We also performed an interventional study in which 36 young and 40 middle-aged and older subjects underwent eight weeks of aerobic exercise training. In the cross-sectional study, serum salusin-α levels were lesser in middle-aged and older subjects compared to young individuals and negatively correlated with age, SBP, DBP, or cfPWV. In the interventional study, exercise training increased serum salusin-α in middle-aged and older subjects. Notably, negative correlations were noted between the exercise training-induced changes in serum salusin-α and cfPWV, SBP and DBP. Results indicate that advanced age associates with low circulating salusin-α, the levels of which can be augmented by exercise training. Importantly, increased serum salusin-α with exercise correlates with improvements in arterial stiffness and a reduction in blood pressure.

Effects of Two Types of Moderate- and High-Intensity Interval Training on Serum Salusin-α and Salusin-β Levels and Lipid Profile in Women with Overweight/Obesity

OBJECTIVE

The current study aimed to compare the effects of two modes of moderate- and high-intensity interval training on serum Salusin-α and Salusin-β and lipid profile in women with overweight/obesity.

SUBJECTS AND METHODS

A number of forty females were assigned to each of (1) Control (BMI= 30.2 ± 2.8 kg/m², n=14), (2) Moderate-intensity (BMI= 31.2 ±3.3 kg/m², n=13) and (3) High-intensity interval training (BMI=30.9±3.4 kg/m², n=13) groups. The subjects of experimental groups participated in the selected interval trainings for eight weeks. The first blood sampling was performed within 48 hours prior to the first training session and the second samples were obtained 48 hours after the last training session.

RESULTS

The findings revealed that there were significant increases in Salusin-α (36% vs. 3%; p = 0.001) and high-density lipoprotein levels (7% vs. 5%; P = 0.039), while significant reductions in the levels of Triglyceride (-8% vs. -9%; p= 0.012) and total cholesterol (-1% vs. -8%; P =0.01) levels of moderate- and high-intensity interval training groups, respectively. Also, there were insignificant changes in Salusin-β (-7% vs. -5%; P = 0.108), low-density lipoproteins (-3% vs. -11%; P =0.046) and very-low-density lipoprotein (-10% vs. -8%; P = 0.056) compared to control group. There were only significant differences between Salusin-α and high-density lipoprotein levels of training groups (P<0.05).

CONCLUSION

It is suggested that, although improvements in lipid profile was nearly similar for two training modes, moderate intensity interval training was more effective to prevent and control atherosclerosis.

Salusin-α levels are negatively correlated with diastolic blood pressure in children with obesity

Salusins have emerged as a new biomarker that reflects an increased inflammatory state, which is associated with cardiovascular risk. We investigated the predictive value and usefulness of salusins as an inflammatory biomarker in obese children. This prospective cohort study included 75 obese children and 101 healthy children (as a control group). Salusin-α, Salusin-β, and various cardiovascular parameters were assessed in both groups. Correlation analyses of Salusin-α and Salusin-β with body mass index standard deviation scores and inflammatory and cardiovascular markers were performed. The mean patient age was 11.9±2.4 years for the obese group and 12.5±2.1 years for the control group. The obese children had a significantly higher heart rate, systolic blood pressure, diastolic blood pressure, epicardial adipose tissue thickness, and left ventricular mass than did the children in the control group. There was no significant correlation between Salusin-α and Salusin-β and body mass index; however, there was a negative correlation between Salusin- α and diastolic blood pressure (r = 0.277, p = 0.004). Overall, there was no significant difference in the Salusin-α and Salusin-β levels between obese and healthy children. However, a negative correlation was found between Salusin-α and diastolic blood pressure. Although this result suggests that Salusin-α might be an early marker of cardiovascular involvement in obese children, further studies are needed to demonstrate the predictive value of salusins.

Silencing salusin β ameliorates heart failure in aged spontaneously hypertensive rats by ROS-relative MAPK/NF-κB pathways in the paraventricular nucleus

OBJECTIVE

Sustained hypertension is a major cause of heart failure in aging hypertensive patients. Salusin β, a novel bioactive peptide of 20 amino acids, has been reported to participate in various cardiovascular diseases, including hypertension. We therefore hypothesized that central knockdown of salusin β might be effective for hypertension-induced heart failure treatment.

METHODS AND RESULTS

Eighteen-month-old male aged spontaneously hypertensive rats (SHR) with heart failure and WKY rats were microinjected with either a specific adenoviral vector encoding salusin β shRNA (Ad-Sal-shRNA) or a scramble shRNA (Ad-Scr-shRNA) in the hypothalamic paraventricular nucleus (PVN) for 4 weeks. Radiotelemetry and echocardiography were used for measuring blood pressure and cardiac function, respectively. Blood samples and heart were harvested for evaluating plasma norepinephrine, tyrosine hydroxylase, and cardiac morphology, respectively. The mesenteric arteries were separated for measurement of vascular responses. The PVN was analyzed for salusin β, proinflammatory cytokines (PICs), mitogen-activated protein kinase (MAPK), NF-κB, and reactive oxygen species (ROS) levels. Compared with normotensive rats, aging SHR with heart failure had dramatically increased salusin β expression. Silencing salusin β with Ad-Sal-shRNA attenuated arterial pressure and improved autonomic function, cardiac and vascular dysfunction in aging SHR with heart failure, but not in aging WKY rats. Knockdown of salusin β significantly reduced paraventricular nucleus PICs levels, MAPK and NF-κB activity, and ROS levels in aging SHR with heart failure.

CONCLUSION

These data demonstrate that in aging SHR, the heart failure that was developed during the end stage of hypertension could be ameliorated by silencing salusin β.

Overexpression of Salusin-α Inhibits Vascular Intimal Hyperplasia in an Atherosclerotic Rabbit Model

Inhibiting vascular endothelial foam is the focus of clinical attention. Using SonoVue (an ultrasound contrast agent), the salusin-α gene was transfected into the arterial intima of an atherosclerotic rabbit model induced by a high-fat diet in this study. Subsequently the model of blood lipid indexes, the pathological structure of the intima, and changes in molecules regulating atherosclerosis were investigated. The high-density lipoprotein C and apolipoprotein A values in the salusin-α gene overexpression (P) group were higher than those in the salusin-α gene interference (RP) group (P < 0.05), whereas the total cholesterol, low-density lipoprotein C, and apolipoprotein B values were reversed. Rabbits in the P group showed significantly thinner vascular intimal thickness than that of other experimental groups (P < 0.05). The expression of positive regulators of atherosclerosis (ABCA1, ABCG1) was higher in the P group than that in the RP group (P < 0.05), and the opposite effect was observed for negative regulators (ACAT1, CD36). Thus, our results showed that the overexpression of salusin-α gene inhibited the proliferation of the vascular intima, thereby throwing some light on understanding the mechanism how salusin-α gene expression interfered with the foaming of vascular intimal cells.

The time changes of endogenous salusin-β in septic rats

Salusin-α and salusin-β are newly found bioactive peptides of 28 and 20 amino acids, respectively, which are widely distributed in the hematopoietic system, endocrine system, and central nervous system. Salusins exert cardiovascular effects, including hypotension and bradycardia; promote vascular inflammation; and so on. However, little information is available yet on the relationships of salusin-β with sepsis. In this study, we investigated the distribution and content of endogenous salusin-β in septic rats. A total of 72 specified pathogen-free (SPF) male Sprague-Dawley (SD) rats were randomly divided into control group (sham operation, n = 36) and experimental group (n = 36) with sepsis rat model by cecal ligation and puncture (CLP). The model group rats were sacrificed after 6, 12, and 24 h of treatment. The concentration of salusin-β in spleen, stomach, small intestine, hypothalamus, and serum specimens was detected by enzyme-linked immunosorbent assay (ELISA). It showed that salusin-β was endogenously generated in rat tissues, including spleen, stomach, small intestine, hypothalamus, and serum. The content of salusin-β in the spleen was higher than that in other tissues. The content of salusin-β in the spleen, stomach, and small intestine, together with the serum level of salusin-β, increased significantly at 6 h after CLP compared with the control group ( P < 0.05). The content of salusin-β in spleen and serum peaked at 12 h, and in small intestine, it reached the summit at 24 h. Meanwhile, no significant fluctuations in salusin-β content were observed in the stomach. The content of salusin-β in hypothalamus began to increase at 6 h, and a significant increase appeared 12 h after CLP ( P < 0.05). In conclusion, this study shows that the time-dependent alterations of salusin-β in septic rats suggest that salusin-β might be involved in the pathogenesis of sepsis.

The cardiovascular functions of salusin-β mediated by muscarinic receptors, glutamate receptors or L-type calcium channels within the rostral ventrolateral medulla of rats

Salusin-α and salusin-β are newly identified bioactive peptides of 28 and 20 amino acids, respectively, that were initially predicted using in silico analyses and are widely distributed in the endocrine system, hematopoietic system, and central nervous system. The goal of our study was to investigate the cardiovascular effect of salusin-β microinjections into the rostral ventrolateral medulla (RVLM) in anesthetized rats and study their mechanism of action. Microinjection of the artificial cerebrospinal fluid (aCSF) into the RVLM did not affect the blood pressure (BP) or heart rate (HR) in anesthetized rats. Topical application of salusin-β into the RVLM produced a dose-dependently increase of BP in anesthetized rats. Microinjection of higher dose salusin-β produced significant tachycardia. Prior application of the L-NAME into the RVLM of rats did not alter the hypertension and tachycardia induced by intra-RVLM salusin-β. Notable, the cardiovascular functions elicited by intra-RVLM salusin-β were significantly decreased by pretreatment with Nic, KYN and atropine. In conclusion, the present study shows that the hypertension and tachycardia induced by intra-RVLM salusin-β might be partly mediated, at least in our opinion, by muscarinic receptors, glutamate receptors or L-type calcium channels.

Overexpression of salusin-β is associated with poor prognosis in ovarian cancer

Ovarian cancer is recognized as one of the worst gynecologic malignancies associated with rapid metastasis and poor overall survival rate. The identified valuable molecular biomarkers criticize importance of timely diagnosis for ovarian cancer. Salusin-β levels are dramatically increased in women with polycystic ovarian syndrome. However, the roles of salusin-β in ovarian cancer have yet to be fully elucidated. A total of 57 paired ovarian cancer specimens and matched adjacent normal tissues were used to measure the salusin-β levels. The prognostic value of salusin-β for tumor progression and survival rate was investigated. The effects of salusin-β on ovarian cancer cell proliferation and epithelial-mesenchymal transition were also explored. The expression of salusin-β was significantly increased in ovarian cancer tissue specimens compared with matched normal adjacent tissue (P<0.05). The high salusin-β level was closely related with FIGO stage and lymph node metastases. The ovarian cancer patients with high salusin-β had a shorter overall survival (P<0.05). Salusin-β obviously enhanced the proliferation and epithelial mesenchymal-transition of SKOV3 cells. Furthermore, salusin-β substantially decreased the expression of p-GSK-3β and GSK-3β, but stimulated the β-catenin expression and downstream genes of wnt/β-catenin including cyclin D1 and C-myc. Our data demonstrated for the first time that upregulated salusin-β may be a novel independent prognostic biomarker for overall survival of ovarian cancer. Salusin-β accelerated the proliferation and epithelial mesenchymal transition of ovarian cancer cells at least partly via activation of Wnt/β-catenin signaling pathway. Salusin-β may be an important target for therapeutic intervention in ovarian cancer.

Salusin-β contributes to vascular inflammation associated with pulmonary arterial hypertension in rats

OBJECTIVE

Inflammation is closely linked to pulmonary arterial hypertension (PAH). Salusin-β, a bioactive peptide, has been reported to participate in vascular inflammation. We therefore hypothesized that salusin-β contributes to monocrotaline (MCT)-induced PAH in rats.

METHODS

Male Sprague-Dawley rats were treated with MCT (60 mg kg(-1), single intraperitoneal injection). Salusin-β expression in the lungs of the MCT-treated rats was evaluated using immunofluorescence staining, western blot, and real-time PCR. For salusin-β blockade assay, rats injected with MCT were given a chronic infusion of anti-salusin-β immunoglobulin G (IgG) (salusin-β blocker, 1.0 μg kg(-1) h(-1)) or isotype-matched control IgG. Four weeks after MCT+anti-salusin-β treatment, the effects of salusin-β blockade were determined using hemodynamics, western blot, real-time PCR, and immunohistochemical detection. The effect of salusin-β on human pulmonary arterial endothelial cell (HPAEC) function was detected by adhesion and tube formation experiments in vitro.

RESULTS

Salusin-β expression was significantly increased in the lungs of the MCT-treated rats, and immunofluorescence results showed that salusin-β was predominantly expressed in pulmonary macrophages and vascular endothelial cells. Salusin-β blockade significantly ameliorated PAH by acting against pulmonary vascular remodeling, decreasing macrophage infiltration, and reducing pro-inflammatory cytokine expression and nuclear factor-kappa B (NF-κB) activity in the lungs of the MCT-treated rats. In addition, salusin-β could induce cell adhesion and accelerate angiogenesis by activating the NF-κB pathway and promoting pro-inflammatory cytokine expression in the cultured HPAECs. This effect was suppressed by addition of the NF-κB inhibitor, N-acetyl-L-cysteine.

CONCLUSIONS

Salusin-β plays a crucial role in the development of MCT-induced PAH models.

Serum salusin-β levels are associated with the presence and severity of coronary artery disease

OBJECTIVES

We sought to assess whether serum salusin-β levels are correlated with the presence and severity of coronary artery disease (CAD).

METHODS

We measured serum salusin-β levels in 278 consecutive patients undergoing coronary angiography (CAG) for the evaluation of CAD and in 126 healthy controls. Serum salusin-β levels were measured by enzyme-linked immunosorbent assay. The severity of CAD was assessed by angiographic coronary atherosclerosis index score system.

RESULTS

Serum salusin-β levels were significantly higher in patients undergoing CAG (n = 278) than those in healthy controls (n = 126) (3.81 ± 0.99 vs 4.34 ± 1.40 nmol/L, P < 0.01). In patients undergoing CAG, patients with CAD (n = 160) had significantly higher serum salusin-β levels compared to patients without CAD (n = 118) (4.65 ± 1.44 vs 3.94 ± 1.23 nmol/L, P < 0.01). Multivariate logistic regression analysis revealed that serum salusin-β levels were independently associated with the presence of CAD (odds ratio, 1.439; 95% confidence interval, 1.176-1.760; P < 0.01). Serum salusin-β levels were positively correlated with the coronary atherosclerosis index score (r = 0.316, P < 0.001).

CONCLUSIONS

Serum salusin-β levels were associated with the presence and severity of CAD. Salusin-β in serum might serve as a potential biomarker for reflecting the development and progression of CAD. Therapeutic treatment by inhibiting salusin-β interaction to prevent CAD warrants further investigation.

Salusin-β induces foam cell formation and monocyte adhesion in human vascular smooth muscle cells via miR155/NOX2/NFκB pathway

Vascular smooth muscle cells (VSMCs) are indispensible components in foam cell formation. Salusin-β is a stimulator in the progression of atherosclerosis. Here, we showed that salusin-β increased foam cell formation evidenced by accumulation of lipid droplets and intracellular cholesterol content, and promoted monocyte adhesion in human VSMCs. Salusin-β increased the expressions and activity of acyl coenzyme A:cholesterol acyltransferase-1 (ACAT-1) and vascular cell adhesion molecule-1 (VCAM-1) in VSMCs. Silencing of ACAT-1 abolished the salusin-β-induced lipid accumulation, and silencing of VCAM-1 prevented the salusin-β-induced monocyte adhesion in VSMCs. Salusin-β caused p65-NFκB nuclear translocation and increased p65 occupancy at the ACAT-1 and VCAM-1 promoter. Inhibition of NFκB with Bay 11-7082 prevented the salusin-β-induced ACAT-1 and VCAM-1 upregulation, foam cell formation and monocyte adhesion in VSMCs. Scavenging ROS, inhibiting NADPH oxidase or knockdown of NOX2 abolished the effects of salusin-β on ACAT-1 and VCAM-1 expressions, p65-NFκB nuclear translocation, lipid accumulation and monocyte adhesion in VSMCs. Salusin-β increased miR155 expression, and knockdown of miR155 prevented the effects of salusin-β on ACAT-1 and VCAM-1 expressions, p65-NFκB nuclear translocation, lipid accumulation, monocyte adhesion and ROS production in VSMCs. These results indicate that salusin-β induces foam formation and monocyte adhesion via miR155/NOX2/NFκB-mediated ACAT-1 and VCAM-1 expressions in VSMCs.

Blockade of Salusin-β in Hypothalamic Paraventricular Nucleus Attenuates Hypertension and Cardiac Hypertrophy in Salt-induced Hypertensive Rats

Salusin-β, a multifunctional bioactive peptide, is considered as a promising candidate biomarker for predicting cardiovascular diseases. This study was designed to determine whether inhibition of salusin-β in the hypothalamic paraventricular nucleus (PVN) delays the progression of hypertension and attenuates cardiac hypertrophy by restoring neurotransmitters and cytokines. Male Sprague Dawley rats were fed with a normal salt diet (NS, 0.3%) or a high salt diet (HS, 8%) for 8 weeks to induce hypertension. Then, these rats received bilateral PVN infusion of a specific salusin-β blocker, antisalusin-β IgG (SIgG), or control IgG (CIgG) for 2 weeks. HS rats exhibited higher mean arterial pressure and cardiac hypertrophy as indicated by increased whole heart weight/bodyweight ratio, whole heart weight/tibia length ratio, left ventricular weight/tibia length ratio, and messenger RNA levels of cardiac atrial natriuretic peptide (ANP), and β-myosin heavy chain. Compared with NS rats, HS rats had higher levels of glutamate, norepinephrine, tyrosine hydroxylase, proinflammatory cytokines, and lower levels of gamma-aminobutyric acid, interleukin 10, and the 67-kDa isoform of glutamate decarboxylase (GAD67) in the PVN, and higher plasma levels of proinflammatory cytokines. Chronic PVN infusion of SIgG attenuated all these changes in HS rats. Our findings suggest that HS rats have an imbalance between excitatory and inhibitory neurotransmitters, as well as an imbalance between proinflammatory and anti-inflammatory cytokines in the PVN; and chronic inhibition of salusin-β in the PVN restores neurotransmitters and cytokines in the PVN, thereby attenuating hypertensive responses and cardiac hypertrophy.

Central blockade of salusin β attenuates hypertension and hypothalamic inflammation in spontaneously hypertensive rats

Salusin β is a multifunctional bioactive peptide and is considered as a promising candidate biomarker for predicting atherosclerotic cardiovascular diseases. The present study was designed to investigate the roles and mechanisms of salusin β in the paraventricular nucleus (PVN) in attenuating hypertension and hypothalamic inflammation and whether central salusin β blockade has protective effects in essential hypertension. Normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were used in this study. The rats were chronic PVN infusion either specific salusin β blocker, antisalusin β IgG (SIgG), or control IgG (CIgG) for 2 weeks. Hypertensive rats had significantly increased salusin β expression compared with normotensive rats. Central blockade of salusin β attenuated hypertension, reduced circulating norepinephrine (NE) levels, and improved cardiac hypertrophy and function in hypertensive rats. Salusin β blockade significantly reduced proinflammatory cytokines (PICs), nuclear factor-kappa B (NF-κB) activity, reactive oxygen species (ROS) levels, and altered renin-angiotensin system (RAS) components in the PVN of hypertensive rats. These findings suggest that the beneficial effects of salusin β blockade in essential hypertension are possibly due to down-regulate of inflammatory molecules and ROS in the PVN.

Salusin-β contributes to vascular remodeling associated with hypertension via promoting vascular smooth muscle cell proliferation and vascular fibrosis

Vascular smooth muscle cell (VSMC) proliferation and vascular fibrosis are closely linked with hypertension and atherosclerosis. Salusin-β is a bioactive peptide involved in the pathogenesis of atherosclerosis. However, it is still largely undefined whether salusin-β is a potential candidate in the VSMC proliferation and vascular fibrosis. Experiments were carried out in human vascular smooth muscle cells (VSMCs) and in rats with intravenous injection of lentivirus expressing salusin-β. In vitro, salusin-β promoted VSMCs proliferation, which was attenuated by adenylate cyclase inhibitor SQ22536, PKA inhibitor Rp-cAMP, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478, ERK inhibitor U0126 or cAMP response element binding protein (CREB) inhibitor KG501. It promoted the phosphorylation of ERK1/2, CREB and EGFR, which were abolished by SQ22536 or Rp-cAMP. Furthermore, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478 diminished the salusin-β-evoked ERK1/2 and CREB phosphorylation. On the other hand, salusin-β increased collagen-I, collagen-III, fibronectin and connective tissue growth factor (CTGF) mRNA and phosphorylation of Smad2/3, which were prevented by ALK5 inhibitor A83-01. In vivo, salusin-β overexpression increased the media thickness, media/lumen ratio coupled with ERK1/2, CREB, EGFR and Smad2/3 phosphorylation, as well as the mRNA of collagen-I, collagen-III, fibronectin, transforming growth factor-β1 (TGF-β1) and CTGF in arteries. Moreover, salusin-β overexpression in rats caused severe hypertension. Intravenous injection of salusin-β dose-relatedly increased blood pressure, but excessive salusin-β decreased blood pressure and heart rate. These results indicate that salusin-β promotes VSMC proliferation via cAMP-PKA-EGFR-CREB/ERK pathway and vascular fibrosis via TGF-β1-Smad pathway. Increased salusin-β contributes to vascular remodeling and hypertension.

Is the serum level of salusin-β associated with hypertension and atherosclerosis in the pediatric population?

BACKGROUND

Salusins are recently identified endogenous bioactive peptides that have hypotensive and bradycardiac effects. Salusin-β is involved in the pathogenesis of human atherosclerosis.

METHODS

This was a prospective cohort study of a young patient population with hypertension (HTN). Based on ambulatory blood pressure monitoring (ABPM), the adolescents were categorized into two groups, namely, a hypertensive group consisting of patients with essential (primary) HTN (HTN group) and a group consisting of patients with white-coat HTN [reference (R) group]. Correlations between serum salusin-β level and clinical, laboratory and ambulatory blood pressure (BP) variables were assessed.

RESULTS

The median salusin-β concentration was significantly higher in patients with essential HTN than in those with white-coat HTN (R group). Salusin-β was positively correlated with the body mass index Z-score, systolic and diastolic blood pressure (BP) from three independent measurements, mean systolic BP during the daytime, triglyceride (TG) level, and atherogenic index (TG/high-density lipoprotein-cholesterol ratio).

CONCLUSIONS

The results of this preliminary study suggest that salusin-β may play an important role in the pathogenesis of HTN in a young population. Further research should focus on the role of salusin-β in the mechanism of essential HTN and the assessment of possible correlations between salusin-β and other well-known markers of atherosclerosis in both teenagers and adults. This research should serve as a base for future studies in this field.