Homocysteine and Its Relationship to Asymptomatic Carotid Stenosis in a Chinese Community Population

Current Biomarkers for Carotid Artery Stenosis: A Comprehensive Review of the Literature

Carotid artery stenosis (CAS), an atherosclerotic disease of the carotid artery, is one of the leading causes of transient ischemic attacks (TIA) and cerebrovascular attacks (CVA). The atherogenic process of CAS affects a wide range of physiological processes, such as inflammation, endothelial cell function, smooth muscle cell migration and many more. The current gold-standard test for CAS is Doppler ultrasound; however, there is yet to be determined a strong, clinically validated biomarker in the blood that can diagnose patients with CAS and/or predict adverse outcomes in such patients. In this comprehensive literature review, we evaluated all of the current research on plasma and serum proteins that are current contenders for biomarkers for CAS. In this literature review, 36 proteins found as potential biomarkers for CAS were categorized in to the following nine categories based on protein function: (1) Inflammation and Immunity, (2) Lipid Metabolism, (3) Haemostasis, (4) Cardiovascular Markers, (5) Markers of Kidney Function, (6) Bone Health, (7) Cellular Structure, (8) Growth Factors, and (9) Hormones. This literature review is the most up-to-date and current comprehensive review of research on biomarkers of CAS, and the only review that demonstrated the several pathways that contribute to the initiation and progression of the disease. With this review, future studies can determine if any new markers, or a panel of the proteins explored in this study, may be contenders as diagnostic or prognostic markers for CAS.

Homocysteine Associated With Low Cognitive Function Independent of Asymptomatic Intracranial and Carotid Arteries Stenoses in Chinese Elderly Patients: An Outpatient-Based Cross-Sectional Study

INTRODUCTION

A high homocysteine (Hcy) concentration is correlated with cognitive impairment; however, the exact underlying mechanism is still not fully elucidated. The present study aimed to investigate whether asymptomatic intracranial and carotid arteries stenoses are involved in Hcy-related low cognitive function.

METHODS

This was a cross-sectional study in outpatient clinics. Residents aged ≥60 years, who came to the Stroke and Rehabilitation Clinic of Shandong Provincial Third Hospital in Jinan, Shandong Province from December 2019 to May 2020 to seek consultation due to abnormal transcranial Doppler reports (eg., increased cerebral blood flow velocity) were eligible. Information including demographics, medical history, lifestyle habits were collected. Fasting blood was used to detect total serum homocysteine level (tHcy). Cerebrovascular magnetic resonance angiography and neck vascular ultrasound examination were used to confirm the diagnosis of intracranial and carotid artery stenoses. The Mini-Mental State Examination was used to assess the cognitive function of each participant. Logistic regression was used to evaluate the relationship between tHcy levels and cognitive function.

RESULTS

This study included 236 participants (mean age: 64.0 (SD, 7.5) years, female: 58.1%). Multivariable analyses adjusted for several potential confounders, including creatinine and cardiovascular risk factors, showed that tHcy was associated with carotid artery stenosis (CAS). After adjusting for CAS, ICAS and several potential confounders, the association between tHcy level and low cognitive function remained significant (odds ratio: 1.09, 95% confidence interval: (1.03, 1.16), P = 0.032) .

CONCLUSION

Increased serum tHcy level was associated with low cognitive function independent of asymptomatic intracranial and carotid arteries stenoses.

Serum Biomarkers in Carotid Artery Disease

Carotid artery disease is considered a major cause of strokes and there is a need for early disease detection and management. Although imaging techniques have been developed for the diagnosis of carotid artery disease and different imaging-based markers have been proposed for the characterization of atherosclerotic plaques, there is still need for a definition of high-risk plaques in asymptomatic patients who may benefit from surgical intervention. Measurement of circulating biomarkers is a promising method to assist in patient-specific disease management, but the lack of robust clinical evidence limits their use as a standard of care. The purpose of this review paper is to present circulating biomarkers related to carotid artery diagnosis and prognosis, which are mainly provided by statistical-based clinical studies. The result of our investigation showed that typical well-established inflammatory biomarkers and biomarkers related to patient lipid profiles are associated with carotid artery disease. In addition to this, more specialized types of biomarkers, such as endothelial and cell adhesion, matrix degrading, and metabolic biomarkers seem to be associated with different carotid artery disease outputs, assisting vascular specialists in selecting patients at high risk for stroke and in need of intervention.

Hyperhomocysteinemia Promotes Carotid Artery Damage in Newly Diagnosed Type 2 Diabetic Patients Without Hypercholesterolemia

Background: The relationship between serum homocysteine levels and carotid artery damage in subjects with newly diagnosed type 2 diabetes mellitus remains unclear. The effect of hyperhomocysteinemia (HHCY) on carotid artery damage in patients with different cholesterol levels needs to be further investigated. Methods: In total 456 newly diagnosed type 2 diabetes from Beijing Chaoyang Hospital were recruited into the study. Patients were divided into four groups according to the levels of serum homocysteine and cholesterol. Carotid artery damage was defined as thickened intima-media and/or plaque formation. Results: In all the subjects, 80.2% patients had HHCY. The incidence of carotid artery injury was significantly lower in diabetic patients with normal homocysteine levels and nonhypercholesterolemia. Spearman correlation analysis showed homocysteine was positively correlated with free fatty acid and negatively correlated with glucose metabolism parameters. Logistic regression showed HHCY was correlated with carotid artery injury after adjusting for traditional cerebrovascular risk factors in type 2 diabetes without hypercholesterolemia (odds risk = 3.197, P = 0.022). Whereas HHCY was not associated with carotid artery injury in either total study population or hypercholesterolemia subgroup. Conclusions: HHCY was correlated with carotid artery damage in newly diagnosed type 2 diabetic subjects without hypercholesterolemia. How to improve the adverse vascular outcomes mediated by HHCY for diabetic patients needed further investigation.

Treatment strategies for asymptomatic carotid artery stenosis in the era of lipid-lowering drugs: protocol for a systematic review and network meta-analysis

INTRODUCTION

Carotid endarterectomy (CEA), carotid artery stenting (CAS) and best medical therapy (BMT) are the major treatments used for significant asymptomatic carotid artery stenosis (ACAS, ≥50%). However, the widespread use of lipid-lowering drugs in this century has improved BMT outcomes. This study aims to compare the treatment efficacy of current BMT, CEA+BMT and CAS+BMT in patients with significant ACAS.

METHODS AND ANALYSIS

This protocol was designed based on the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Publication time for studies will be set from 1 January 2000 to 1 June 2020. We will search three databases: PubMed, EMBASE and The Cochrane Library. Suitable randomised controlled studies will be screened. The primary outcomes will include short-term and long-term mortality, stroke and myocardial infarction. OR and HR for dichotomous data and time-to-event data with 95% CIs will be calculated. Treatment effects among different therapies will be ranked according to the surface under the cumulative ranking curve and mean rank. A comprehensive evaluation of the risk of bias, heterogeneity and transitivity will be performed before data synthesis. Consistency and evidence quality will also be assessed.

ETHICS AND DISSEMINATION

There will be no need for ethics approval as this systematic review is a summary and analysis of existing literature. Final results may be presented in international conferences or a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42019138942.

Review of serum biomarkers in carotid atherosclerosis

BACKGROUND

Carotid artery atherosclerotic stenosis is a preventable major cause of stroke, but there is still a need for definition of high-risk plaque in asymptomatic patients who might benefit from interventional therapies. Several image markers are recommended to characterize unstable plaques. The measurement of serum biomarkers is a promising method to assist in decision making, but the lack of robust evidence in the carotid environment burdens their potential as a standard of care. The goal of this review was to offer an updated state-of-the-art study of available serum biomarkers with clinical implications, with focus on those that may predict carotid symptom development.

METHODS

The Cochrane Library and MEDLINE databases were searched (all until September 2018) for studies on carotid plaque and serum biomarkers of atherosclerosis. Nonhuman, basic science, and histology studies were excluded, focusing on clinical studies. Selected abstracts were screened to include the most relevant articles on atherosclerotic plaque presence, progression, instability or symptom development.

RESULTS

Some well-established biomarkers for coronary disease are not relevant to carotid atherosclerosis and other inflammatory biomarkers, lipids, interleukins, homocysteine, and adipokines may be useful in quantifying carotid disease-related risk. Some serum biomarkers combined with image features may assist vascular specialists in selecting patients at high risk for stroke and in need of intervention.

CONCLUSIONS

Prospective studies applying a combination of biomarkers are essential to prove clinical usefulness.

Changes in total homocysteine levels after acute stroke and recurrence of stroke

It is not known how total homocysteine (tHcy) levels change during the transition from acute stroke to post-stroke convalescence or whether tHcy changes occurring after the acute period are associated with recurrence of cerebro-cardiovascular events. Levels of tHcy were measured during acute ischemia and again after three months. Patients were followed for a median of 18 (range: 12–36) months. A total of 2800 patients who had at least two tHcy measurements were enrolled between February 2012 and June 2014; 2587 patients presented with ischemic stroke and 213 presented with cerebral hemorrhage. During the follow-up period, 220 (7.9%) patients experienced another ischemic event. After adjusting for additional cardiovascular risk factors, patients with the highest levels of tHcy (fourth quartile; >15.5 μmol/L) had a 1.76-fold increased risk of a recurrence (adjusted HR: 1.76, 95%CI: 1.11–3.08) as compared to patients with the lowest levels of tHcy (lowest quartile; ≤9.65 μmol/L). Additional analysis by subgroup indicated that this correlation was only significant for patients with large-artery atherosclerosis ischemia (adjusted HR: 2.00, 95%CI: 1.13–3.55). Elevated tHcy during the convalescent phase of acute stroke was independently associated with an increased risk of recurrent ischemic stroke, especially in those patients with large-vessel atherosclerosis ischemia.

Association between homocysteine and conventional predisposing factors on risk of stroke in patients with hypertension

Previous studies have focused mostly on independent effects of the stroke risk factors, whereas little attention has been paid to interactions between individual factors which may be important for stroke prevention. We collected data related to the patients' demographic characteristics, history of chronic diseases and lifestyle factors in 2258 patients with primary hypertension. Logistic regression models based on odds ratio (OR) with their associated 95% confidence interval (CI) were used to estimate an independent effect of homocysteine (Hcy) on the risk of stroke but also include the interactions between Hcy and other risk factors. Hcy was associated with an increased OR of the risk of stroke in both hypertension patients (OR, 1.027; 95% CI, 1.016-1.038; P < 0.001) and H-type hypertension patients (OR, 1.026; 95% CI, 1.014-1.037; P < 0.001), after adjustment for potential confounding factors. Among the hypertension participants, three tests of interactions between Hcy and other risk factors were statistically significant: sex, systolic blood pressure and diastolic blood pressure. In conclusion, complexities of the interactions of Hcy stratified by sex and blood pressure need to be considered in predicting overall risk and selecting certain treatments for stroke prevention.