Correlation between serum sortilin levels and severity of extracranial carotid artery stenosis

Dysregulation of proBDNF/p75NTR and BDNF/TrkB Signaling in Acute Ischemic Stroke: Different Sides of the Same Coins

Acute ischemic stroke (AIS) is a focal neurological deficit due to sudden occlusion of cerebral vessels in the brain. AIS-induced neuronal injury and associated excite-toxicity and neurodegeneration affect the synthesis and the release of different neurotrophic factors such as brain-derived neurotropic factor (BDNF) and its precursor proBDNF. Both BDNF and proBDNF act on the specific receptors with different neurological effects. BDNF activates tropomyosin receptor kinase B (TrkB) receptor results in promoting neuronal survival, synaptic plasticity, and neuronal growth. However, the proBDNF activates p75 neurotrophin receptor (p75NTR) and sortilin which attenuates synaptic plasticity and promotes neuronal apoptosis. Dysregulation of central and peripheral expression of proBDNF/BDNF is linked with the severity and clinical outcomes of AIS. Therefore, this review aims to discuss the alterations of proBDNF/BDNF signaling in AIS. Findings from the present review illustrated that proBDNF/p75NTR/sortilin signaling pathway is exaggerated whereas; BDNF-TrkB signaling is reduced in AIS leading to neuronal apoptosis. Therefore, activation of BDNF-TrkB signaling, and inhibition of proBDNF/p75NTR/sortilin signaling pathway could be a promising therapeutic strategy in the management of AIS.

Sortilin and hypertension

PURPOSE OF REVIEW

The current review aims to present the latest scientific updates on the role of Sortilin in the pathophysiology of hypertension.

RECENT FINDINGS

The main focus of this systematic overview is on the functional contribution of Sortilin to the pathogenesis of hypertension. Sortilin is a glycoprotein mostly known for its actions as a trafficking molecule directing proteins to specific secretory or endocytic compartments of the cell. Emerging evidence indicates that Sortilin is associated with pathological conditions, including inflammation, arteriosclerosis, dyslipidemia, insulin resistance, and vascular calcification. Most recently, Sortilin has been shown to finely control endothelial function and to drive hypertension by modulating sphingolipid/ceramide homeostasis and by triggering oxidative stress.

SUMMARY

The latest findings linking Sortilin and hypertension that are herein discussed can inspire novel areas of research which could eventually lead to the discovery of new therapeutic strategies in cardiovascular medicine.

The association of plasma sortilin with essential hypertension and subclinical carotid atherosclerosis: A cross-sectional study

Background

Sortilin, a protein that regulates glucose and lipid metabolism, has recently been linked to cardiovascular diseases (CVDs) such as coronary heart disease and carotid artery stenosis. In this study, we measured circulating sortilin concentrations in essential hypertensive (EH) patients, and evaluated the association between sortilin, hypertension, and subclinical carotid atherosclerosis in hypertensive individuals.

Methods

This cross-sectional study included 336 individuals, including 186 newly diagnosed EH patients and 150 age-and-sex-matched normotensive healthy subjects (NT). Plasma sortilin and adiponectin (ADI) levels were measured using ELISA kits. In the EH group, high-resolution B-mode ultrasound was used to detect the existence of subclinical carotid atherosclerosis (subAS), which was defined as having a carotid intima–media thickness (cIMT) ≥ 1.0 mm and/or plaque on the carotid artery without any clinical manifestations.

Results

Our findings showed that plasma sortilin concentrations ranged from 3.34–11.34 ng/ml for all subjects. Sortilin levels were significantly higher in the EH group than in the NT group (8.10 ± 1.82 ng/ml vs. 6.37 ± 1.52 ng/ml, P < 0.001) and were further upregulated in the EH with subclinical carotid atherosclerosis (EH + subAS) group compared to the EH without subclinical carotid atherosclerosis (EH-subAS) group (8.42 ± 1.75 ng/ml vs. 7.79 ± 1.84 ng/ml, P < 0.05). In correlation analysis, sortilin was positively correlated with systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), white blood cell (WBC), endothelin-1 (ET-1), high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and cIMT (all P < 0.05) and negatively associated with NO and ADI (P < 0.001). Multiple linear regression analysis revealed that SBP, LDL-C, and ET-1 were independently associated with plasma sortilin levels. Increased sortilin levels were independently associated with the risk of EH (OR: 1.86, 95%CI: 1.56–2.20, P < 0.001) and EH + subAS (OR: 1.33, 95%CI: 1.07–1.66, P = 0.011), after adjustment for multiple risk factors. Restricted spline curve showed that elevated sortilin levels increase the odds of having EH.

Conclusion

Elevated sortilin levels are associated with an increased risk of essential hypertension and subclinical carotid atherosclerosis in hypertensive patients.