Hyperhomocysteinemia associates with small vessel disease more closely than large vessel disease

Blood-based biomarkers of cerebral small vessel disease

Age-associated cerebral small vessel disease (CSVD) represents a clinically heterogenous condition, arising from diverse microvascular mechanisms. These lead to chronic cerebrovascular dysfunction and carry a substantial risk of subsequent stroke and vascular cognitive impairment in aging populations. Owing to advances in neuroimaging, in vivo visualization of cerebral vasculature abnormities and detection of CSVD, including lacunes, microinfarcts, microbleeds and white matter lesions, is now possible, but remains a resource-, skills- and time-intensive approach. As a result, there has been a recent proliferation of blood-based biomarker studies for CSVD aimed at developing accessible screening tools for early detection and risk stratification. However, a good understanding of the pathophysiological processes underpinning CSVD is needed to identify and assess clinically useful biomarkers. Here, we provide an overview of processes associated with CSVD pathogenesis, including endothelial injury and dysfunction, neuroinflammation, oxidative stress, perivascular neuronal damage as well as cardiovascular dysfunction. Then, we review clinical studies of the key biomolecules involved in the aforementioned processes. Lastly, we outline future trends and directions for CSVD biomarker discovery and clinical validation.

Association between MTHFR C677T polymorphism and cognitive impairment in patients with cerebral small vessel disease: a cross-sectional study

Objective

Cerebral small vessel disease (CSVD) is the most common vascular cause of cognitive impairment. This study aimed to explore the association between MTHFR C677T polymorphism and cognitive impairment in CSVD patients.

Methods

Demographic, medical, laboratory, cognitive evaluation, and MTHFR C677T polymorphism data were collected from CSVD patients admitted to our hospital between January 2019 and July 2023. Inclusion criteria for CSVD were based on the Standards for Reporting Vascular changes on Neuroimaging (STRIVE) criteria, with age ≥ 45 years. Binary logistic regression models were used to analyze risk factors associated with WMH and cognitive impairment.

Results

A total of 330 CSVD participants were recruited in this study, including 179 male and 151 female, with a median age of 64 years (interquartile range: 58-73 years). There were 185 patients (56.1%) with cognitive impairment, 236 patients (71.5%) with WMH, 89 patients (27.0%) with CMB, 87 patients (26.4%) with lacunes. All participants completed MTHFR polymorphism analysis, 149 cases (45.2%) of the CC genotype, 112 cases (33.9%) of the CT genotype and 69 cases (20.9%) of the TT genotype. Patients with TT genotype exhibited higher plasma homocysteine levels and more severe WMH and cognitive impairment (p < 0.001). Multivariable binary logistic regression model showed that WMH was significantly associated with age (p = 0.019), history of hypertension (p = 0.011), HHcy (p = 0.019) and MTHFR genotype (p = 0.041); while cognitive impairment was significantly associated with age (p = 0.033), history of hypertension (p = 0.019), HHcy (p = 0.040), MTHFR genotype (p = 0.039), WMH (p = 0.041), and lacunes (p = 0.001).

Conclusion

In this cross-sectional study, we investigated the association between MTHFR C677T polymorphism and cognitive function in CSVD patients. We found that MTHFR 677 TT genotype was an independent risk factor for the progression of WMH and cognitive impairment in CSVD patients.

Association of Homocysteine with Acute Stroke and Its Subtypes in the Chinese Population

Purpose

Homocysteine (Hcy) is recognized as a risk factor for stroke. Our study examined the relationship between plasma Hcy levels and stroke, along with its subtypes, among Chinese patients who experienced an acute stroke episode.

Patients and Methods

We retrospectively enrolled patients with acute stroke and age- and sex-matched healthy controls admitted to the First Affiliated Hospital of Xi'an Jiaotong University from October 2021 to September 2022. Ischemic stroke subtypes were classified using the modified TOAST criteria. Multivariate logistic regression models were employed to probe the associations of plasma Hcy levels with total stroke, ischemic stroke and its subtypes, and hypertensive intracerebral hemorrhage (HICH), and the correlation between plasma Hcy levels and the National Institute of Health Stroke Scale (NIHSS).

Results

The mean age of the total group was 63 years, with women representing 30.6% (246 individuals). Elevated Hcy levels were significantly associated with total stroke (OR 1.054, 95% CI: 1.038-1.070), HICH (OR 1.040, 95% CI: 1.020-1.060), ischemic stroke (OR 1.049, 95% CI: 1.034-1.065), and the TOAST subtypes of ischemic stroke in large-artery atherosclerosis (LAA) (OR 1.044, 95% CI: 1.028-1.062) and small-artery occlusion (SAO) (OR 1.035, 95% CI: 1.018-1.052), but not with cardioembolic (CE) stroke. Moreover, only in the case of SAO stroke were the Hcy levels positively correlated with the NIHSS score (B=0.030, 95% CI: 0.003-0.056, P=0.030).

Conclusion

Plasma Hcy levels were found to be positively correlated with the risk of stroke, particularly in the context of LAA, SAO stroke, and HICH. Additionally, Hcy levels demonstrated a positive correlation with stroke severity in patients presenting with SAO stroke. These findings suggest potential clinical implications in stroke prevention, particularly for ischemic stroke (LAA, SAO subtypes) and HICH by employing homocysteine-lowering therapies. Future investigations are warranted to fully elucidate these associations.

Using Bayesian networks with Tabu-search algorithm to explore risk factors for hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) is a condition closely associated with cardiovascular and cerebrovascular diseases. Detecting its risk factors and taking some relevant interventions still represent the top priority to lower its prevalence. Yet, in discussing risk factors, Logistic regression model is usually adopted but accompanied by some defects. In this study, a Tabu Search-based BNs was first constructed for HHcy and its risk factors, and the conditional probability between nodes was calculated using Maximum Likelihood Estimation. Besides, we tried to compare its performance with Hill Climbing-based BNs and Logistic regression model in risk factor detection and discuss its prospect in clinical practice. Our study found that Age, sex, α1-microgloblobumin to creatinine ratio, fasting plasma glucose, diet and systolic blood pressure represent direct risk factors for HHcy, and smoking, glycosylated hemoglobin and BMI constitute indirect risk factors for HHcy. Besides, the performance of Tabu Search-based BNs is better than Hill Climbing-based BNs. Accordingly, BNs with Tabu Search algorithm could be a supplement for Logistic regression, allowing for exploring the complex network relationship and the overall linkage between HHcy and its risk factors. Besides, Bayesian reasoning allows for risk prediction of HHcy, which is more reasonable in clinical practice and thus should be promoted.

Plasma inflammatory biomarkers in cerebral small vessel disease: A review

Cerebral small vessel disease (CSVD) is a group of pathological processes affecting small arteries, arterioles, capillaries, and small veins of the brain. It is one of the most common subtypes of cerebrovascular diseases, especially highly prevalent in elderly populations, and is associated with stroke occurrence and recurrence, cognitive impairment, gait disorders, psychological disturbance, and dysuria. Its diagnosis mainly depends on MRI, characterized by recent small subcortical infarcts, lacunes, white matter hyperintensities (WMHs), enlarged perivascular spaces (EPVS), cerebral microbleeds (CMBs), and brain atrophy. While the pathophysiological processes of CSVD are not fully understood at present, inflammation is noticed as playing an important role. Herein, we aimed to review the relationship between plasma inflammatory biomarkers and the MRI features of CSVD, to provide background for further research.

Unilateral Blindness in Post Septoplasty Due to Homocysteinemia: A Rare Presentation

Septoplasty is a common operative procedure in ENT for correction of nasal septal deformity. Rarely it may result into devastating complication like vision loss. This may be related to other causes apart from septoplasty. The author presents a 27 yrs old male admitted to our hospital for septoplasty, 1 h after septoplasty the patient suffered from unilateral vision loss. After thorough examination and investigation the vision loss was found to be due to homocysteinemia. Hence homocysteinemia is one of the rare cause of vision loss in post septoplasty. Thus this is a rare presentation.

Dose-response association between plasma homocysteine and white matter lesions in patients with hypertension: a case-control study

White matter lesions (WMLs) are common MRI changes that are indicative of cerebral small vessel disease (CSVD). Elevated plasma homocysteine (Hcy) levels are related to an increased risk of vascular disease. We aimed to analyze the relationship between Hcy levels and WMLs in patients with hypertension. A total of 1961 patients with WMLs and 15,463 patients without WMLs were matched at a 1:1 ratio by age and sex. Hyperhomocysteinemia (HHcy) was defined as an abnormally high level (>15 µmol/l) of Hcy in a plasma sample. In total, 1888 (WML group) and 1888 (No-WMLs group) patients were enrolled, with 51.6% of the sample being male and a mean age of 63 years. Multivariate logistic regression analysis showed a significant association between a higher level of plasma Hcy and a higher prevalence of WMLs (OR 1.03 95% CI, 1.02-1.04) when the Hcy level was used as a continuous variable. Patients with Hcy levels of 15-20 µmol/l (OR 1.54, 95% CI 1.31-1.81) and >20 µmol/l (OR 1.51, 95% CI 1.26-1.82) also had a significantly higher risk of WMLs than patients with Hcy levels <15 µmol/l. Multivariable-adjusted spline regression models showed that the risk of WMLs started to increase only in patients with Hcy levels above 13.85 µmol/l (P < 0.001). In subgroup analyses of WMLs, there was no significant interaction between the Hcy group and subgroup heterogeneity for the prevalence of WMLs (P > 0.05). Our study found a dose-response association between plasma homocysteine levels, especially a Hcy level >13.85 µmol/l, and the prevalence of WMLs, implying that lowering Hcy levels might be a target for prevention.

Differential associations of lipoprotein(a) level with cerebral large artery and small vessel diseases

BACKGROUND AND PURPOSE

Cerebral large artery and small vessel diseases are related to different pathogenetic mechanisms and have different risk factor profile. Lipoprotein(a) (Lp(a)) was shown to promote atherosclerosis but data was limited on its association with cerebral small vessel diseases (cSVD). The objective of this study was to assess the associations of Lp(a) level with the two types of cerebrovascular diseases.

METHODS

Community-dwelling subjects aged 50-75 years from the baseline survey of The PolyvasculaR Evaluation for Cognitive Impairment and vaScular Events study were included. Lp(a) concentrations was measured and categorised into three groups according to the tertiles. Eligible participants were scanned by a 3.0T MRI scanner and assessed for intracranial atherosclerosis and cSVD burden based on four imaging markers.

RESULTS

This study included 3059 subjects. The average age of the participants was 61.2±6.7 years, and 53.5% (1636) were female. Compared with the first tertile, subjects with the second and third tertiles of Lp(a) concentrations were associated with an increased odds of presence of intracranial plaque (18.7% vs 15.4%, adj.OR 1.37, 95% CI 1.08 to 1.75; 18.9% vs 15.4%, adj.OR 1.34, 95% CI 1.05 to 1.72). Similar associations were observed for intracranial atherosclerotic burden. Whereas, subjects with the third tertile of Lp(a) level had a decreased odds of presence of cSVD (25.9% vs 31.7%, adj.OR 0.74, 95% CI 0.60 to 0.92) and lower cSVD burden (adj.cOR 0.76, 95% CI 0.62 to 0.94).

CONCLUSIONS

In this study, Lp(a) concentrations were positively associated with presence and burden of intracranial atherosclerosis, but was inversely associated with cSVD.

TRIAL REGISTRATION NUMBER

NCT03178448.

Diagnostic Values of Serum Levels of Homocysteine, Heat Shock Protein 70 and High-Sensitivity C-Reactive Protein for Predicting Vascular Cognitive Impairment

INTRODUCTION

Vascular cognitive impairment is one of the main clinical manifestations of cerebral small vessel disease (CSVD). Reliable molecular markers are needed urgently to predict cognitive impairments in CSVD patients. This study aimed to investigate the possible diagnostic values of serum levels of Hcy, Hsp70 and hs-CRP for predicting vascular cognitive impairment in patients with CSVD.

METHODS

According to the presence of CSVD and cognitive impairment (CI), healthy patients and CSVD patients were divided into three groups. Serum Hcy, HSP70 and hs-CRP were abnormal in the CI group. Clinical characteristics and MOCA cognitive function score statistics were performed for the three groups: the control group, CSVD without cognitive impairment group and CSVD with cognitive impairment group. Finally, Hcy, HSP70 and hs-CRP were correlated with MOCA to analyze the correlation between serum Hcy, HSP70 and hs-CRP and cognitive dysfunction caused by CSVD.

RESULTS

The levels of serum Hcy, Hsp70, and hsCRP had significantly higher expression in the CSVD groups than those in the control group (p<0.05). Moreover, basic clinical characteristics, cardiovascular risk factors and other clinical details had no significantly differences among the three groups. Serum Hcy, Hsp70 and hs-CRP levels were negatively correlated with MoCA total scores.

CONCLUSION

Serum levels of Hcy, HSP70 and hs-CRP were negatively correlated with cognitive impairment caused by CSVD, which could be used as a predictor to predict the risk of cognitive impairment caused by CSVD.

Endothelial Dysfunction and Hyperhomocysteinemia-Linked Cerebral Small Vessel Disease: Underlying Mechanisms and Treatment Timing

Cerebral small vessel disease (cSVD)—a common cause of stroke and vascular dementia—is a group of clinical syndromes that affects the brain's small vessels, including arterioles, capillaries, and venules. Its pathogenesis is not fully understood, and effective treatments are limited. Increasing evidence indicates that an elevated total serum homocysteine level is directly and indirectly associated with cSVD, and endothelial dysfunction plays an active role in this association. Hyperhomocysteinemia affects endothelial function through oxidative stress, inflammatory pathways, and epigenetic alterations at an early stage, even before the onset of small vessel injuries and the disease. Therefore, hyperhomocysteinemia is potentially an important therapeutic target for cSVD. However, decreasing the homocysteine level is not sufficiently effective, possibly due to delayed treatment, which underlying reason remains unclear. In this review, we examined endothelial dysfunction to understand the close relationship between hyperhomocysteinemia and cSVD and identify the optimal timing for the therapy.

Effect of folic acid combined with pravastatin on arteriosclerosis in elderly hypertensive patients with lacunar infarction

ABSTRACT

This study aimed to assess the effect of folic acid combined with pravastatin on atherosclerosis-related indexes in elderly patients with hypertension complicated with lacunar cerebral infarction.A total of 134 elderly hypertensive patients with lacunar cerebral infarction were randomly divided into 3 groups using the random number table method. Group A, the folic acid group, had 45 cases and received low-dose folic acid (0.8 mg/d) treatment on the basis of antihypertensive treatment. Group B, the pravastatin group, had 45 cases and received pravastatin (20 mg/d) treatment on the basis of antihypertensive treatment. Group C, the folic acid combined with the pravastatin group, had 44 cases. Members of this group received pravastatin (20 mg/d) and low-dose folic acid (0.8 mg/d) based on antihypertensive treatment. Levels of folic acid, homocysteine (Hcy), tumor necrosis factor alpha (TNF-a), matrix metallopeptidase 9 (MMP-9), cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) were measured by ELISA before treatment in all 3 groups. Carotid intima-media thickness (IMT) was measured using ultrasound, and systolic and diastolic blood pressure were measured with a mercury column. After 8 weeks of treatment, the levels of folic acid, Hcy, TNF-a, MMP-9, TC, LDL-C, and systolic and diastolic blood pressure were compared among the 3 groups. IMT levels were measured at 12 weeks of treatment.After 8 weeks of treatment, compared with group B, patients in groups A and C had folic acid levels significantly higher than baseline levels, with significantly lower Hcy levels (both P < .05). Patients in group C presented significantly decreased TNF-a, MMP-9, TC, and LDL-C levels and systolic and diastolic blood pressure after 8 weeks of treatment, compared with those in groups A and B (both P < .05). These patients also showed significantly decreased IMT levels compared with those in the other groups (P < .05).Low-dose folic acid combined with pravastatin in elderly patients with lacunar cerebral infarction can reduce the level of homocysteine, improve the degree of carotid atherosclerosis, protect vascular endothelium, and reduce blood lipids and blood pressure, presenting better benefits than pravastatin alone.

A Mendelian Randomization Study of Plasma Homocysteine Levels and Cerebrovascular and Neurodegenerative Diseases

Background: Homocysteine (Hcy) is a toxic amino acid and hyperhomocysteinemia (HHcy) was reported to be associated with both cerebrovascular disease and neurodegenerative disease. Our aim was to assess the causal link between plasma Hcy level and cerebrovascular and neurodegenerative diseases through a Mendelian randomization (MR) study.

Methods: A two-sample MR study was performed to infer the causal link. We extracted the genetic variants (SNPs) associated with plasma Hcy level from a large genome-wide association study (GWAS) meta-analysis. The main MR analysis was performed using the inverse variance-weighted method. Additional analyses were further performed using MR-Egger intercept and Cochran’s Q statistic to detect the heterogeneity or pleiotropy of our findings.

Results: Thirteen Hcy-associated SNPs were selected as instrumental variables. The results showed evidence of a causal link between plasma Hcy level and ischemic stroke (IS) caused by small artery occlusion (SAS, OR = 1.329, 95% CI 1.047–1.612, p = 0.048). Meanwhile, there was no evidence of association between plasma Hcy level and other types of IS, transient ischemic attack (TIA), or neurodegenerative disease. The MR-Egger intercept test indicated no evidence of directional pleiotropy. Results of additional MR analysis indicated that blood pressure (BP) and type 2 diabetes mellitus (T2DM) serve as influencers in the association.

Conclusion: The MR study found a little causal link between plasma Hcy level and SAS. The link is likely to be influenced by other risk factors like BP and T2DM.

Endothelial Dysfunction May Link Interatrial Septal Abnormalities and MTHFR-Inherited Defects to Cryptogenic Stroke Predisposition

We explored the significance of the L-Arginine/asymmetric dimethylarginine (L-Arg/ADMA) ratio as a biomarker of endothelial dysfunction in stroke patients. To this aim, we evaluated the correlation, in terms of severity, between the degree of endothelial dysfunction (by L-Arg/ADMA ratio), the methylene tetrahydrofolate reductase (MTHFR) genotype, and the interatrial septum (IAS) phenotype in subject with a history of stroke. Methods and Results: L-Arg, ADMA, and MTHFR genotypes were evaluated; the IAS phenotype was assessed by transesophageal echocardiography. Patients were grouped according to the severity of IAS defects and the residual enzymatic activity of MTHFR-mutated variants, and values of L-Arg/ADMA ratio were measured in each subgroup. Of 57 patients, 10 had a septum integrum (SI), 38 a patent foramen ovale (PFO), and 9 an ostium secundum (OS). The L-Arg/ADMA ratio differed across septum phenotypes (p ≤ 0.01), and was higher in SI than in PFO or OS patients (p ≤ 0.05, p ≤ 0.01, respectively). In the PFO subgroup a negative correlation was found between the L-Arg/ADMA ratio and PFO tunnel length/height ratio (p ≤ 0.05; r = − 0.37; R2 = 0.14). Interestingly, the L-Arg/ADMA ratio varied across MTHFR genotypes (p ≤ 0.0001) and was lower in subgroups carrying the most impaired enzyme with respect to patients carrying the conservative MTHFR (p ≤ 0.0001, p ≤ 0.05, respectively). Consistently, OS patients carried the most dysfunctional MTHFR genotypes, whereas SI patients the least ones. Conclusions: A low L-Arg/ADMA ratio correlates with impaired activity of MTHFR and with the jeopardized IAS phenotype along a severity spectrum encompassing OS, PFO with long/tight tunnel, PFO with short/large tunnel, and SI. This infers that genetic MTHFR defects may underlie endothelial dysfunction-related IAS abnormalities, and predispose to a cryptogenic stroke. Our findings emphasize the role of the L-Arg/ADMA ratio as a reliable marker of stroke susceptibility in carriers of IAS abnormalities, and suggest its potential use both as a diagnostic tool and as a decision aid for therapy.

Postoperative Symptomatic Cerebral Infarction in Pediatric Moyamoya Disease: Risk Factors and Clinical Outcome

BACKGROUND

Indirect bypass surgery is used to improve the hemodynamic status of pediatric patients with moyamoya disease (MMD). Symptomatic cerebral infarction during the early postoperative period may be the most frustrating complication. This study was conducted to investigate the factors associated with early postoperative symptomatic cerebral infarction.

METHODS

Between January 2000 and February 2014, we performed 1241 indirect bypass surgeries in 659 pediatric MMD patients. Symptomatic infarction during the early postoperative period was diagnosed in 63 operations in 61 patients.

RESULTS

The overall incidence of symptomatic cerebral infarction after indirect bypass surgery was 5.1%. The median age of the patients with postoperative infarction was 6 years (mean, 6.4 years; range, 1-15 years). The performance of 2 craniotomies in single operation was associated with a higher rate of cerebral infarction. Moreover, the incidence was higher in young patients (age <6 years) compared with older patients. In a matched analysis, an immediate postoperative hemoglobin level >13 g/dL was associated with decreased risk of infarction (odds ratio, 0.144; P = 0.003). Mutation of the methylenetetrahydrofolate reductase (MTHFR) gene occurred in a relatively high proportion of our infarction cohort.

CONCLUSIONS

Postoperative symptomatic infarctions can occur despite a unified surgical method and formulaic perioperative management protocol. Patient-centered factors, such as young age, genetic background of MTHFR, and certain medical conditions, including hyperthyroidism, renovascular hypertension, and hemolytic uremic syndrome, as well as management-related factors, including 2 craniotomies and low immediate postoperative hemoglobin level, could be risk factors for early postoperative symptomatic cerebral infarction.

Inflammation and cerebral small vessel disease: A systematic review

Inflammation is increasingly implicated as a risk factor for dementia, stroke, and small vessel disease (SVD). However, the underlying mechanisms and causative pathways remain unclear. We systematically reviewed the existing literature on the associations between markers of inflammation and SVD (i.e., white matter hyperintensities (WMH), lacunes, enlarged perivascular spaces (EPVS), cerebral microbleeds (CMB)) in cohorts of older people with good health, cerebrovascular disease, or cognitive impairment. Based on distinctions made in the literature, markers of inflammation were classified as systemic inflammation (e.g. C-reactive protein, interleukin-6, fibrinogen) or vascular inflammation/endothelial dysfunction (e.g. homocysteine, von Willebrand factor, Lp-PLA2). Evidence from 82 articles revealed relatively robust associations between SVD and markers of vascular inflammation, especially amongst stroke patients, suggesting that alterations to the endothelium and blood-brain barrier may be a driving force behind SVD. Conversely, cross-sectional findings on systemic inflammation were mixed, although longitudinal investigations demonstrated that elevated levels of systemic inflammatory markers at baseline predicted subsequent SVD severity and progression. Importantly, regional analysis revealed that systemic and vascular inflammation were differentially related to two distinct forms of SVD. Specifically, markers of vascular inflammation tended to be associated with SVD in areas typical of hypertensive arteriopathy (e.g., basal ganglia), while systemic inflammation appeared to be involved in CAA-related vascular damage (e.g., centrum semiovale). Nonetheless, there is insufficient data to establish whether inflammation is causal of, or secondary to, SVD. Findings have important implications on interventions, suggesting the potential utility of treatments targeting the brain endothelium and blood brain barrier to combat SVD and associated neurodegenerative diseases.

Study of the Inflammatory Mechanisms in Hyperhomocysteinemia on Large-Artery Atherosclerosis Based on Hypersensitive C-Reactive Protein-A Study from Southern China

OBJECTIVE

To study the inflammatory mechanism of hyperhomocysteinemia on large-artery atherosclerosis based on hypersensitive C-reactive protein in patients.

METHODS

In all, 153 inpatients and 1357 physical examinees were selected. The levels of homocysteine were compared between the carotid/intracranial artery stenosis group and the nonstenosis group, between the carotid artery unstable plaque group and the nonplaque group, and between the intima-media thickness (IMT) greater than or equal to 1 group and the normal IMT group. The hypersensitive C-reactive protein levels were compared between the lacunar infarction (LI) group and the nonstroke control group and between the unstable plaque group and the nonplaque group.

RESULTS

Homocysteine level was significantly higher in the carotid/intracranial artery stenosis group than in the nonstenosis group, in the LI group than in the inpatient nonstroke group, and in the IMT greater than or equal to 1 group than in the normal IMT group. The hypersensitive C-reactive protein level was significantly higher in the LI group than in the nonstroke group and in the unstable plaque group than in the nonplaque group.

CONCLUSIONS

Hyperhomocysteinemia may aggravate the development of IMT, carotid atherosclerotic plaque instability, and carotid/intracranial artery stenosis by increasing inflammation, ultimately leading to the occurrence of LI. Hyperhomocysteinemia-induced inflammation mechanism warrants further study.

Homocysteine and small vessel stroke: A mendelian randomization analysis

Objective

Trials of B vitamin therapy to lower blood total homocysteine (tHcy) levels for prevention of stroke are inconclusive. Secondary analyses of trial data and epidemiological studies suggest that tHcy levels may be particularly associated with small vessel stroke (SVS). We assessed whether circulating tHcy and B vitamin levels are selectively associated with SVS, but not other stroke subtypes, using Mendelian randomization.

Methods

We used summary statistics data for single‐nucleotide polymorphisms (SNPs) associated with tHcy (n = 18), folate (n = 3), vitamin B₆ (n = 1), and vitamin B₁₂ (n = 14) levels, and the corresponding data for stroke from the MEGASTROKE consortium (n = 16,952 subtyped ischemic stroke cases and 404,630 noncases).

Results

Genetically predicted tHcy was associated with SVS, with an odds ratio of 1.34 (95% confidence interval [CI], 1.13–1.58; p = 6.7 × 10^–4) per 1 standard deviation (SD) increase in genetically predicted tHcy levels, but was not associated with large artery or cardioembolic stroke. The association was mainly driven by SNPs at or near the MTHFR and MUT genes. The odds ratios of SVS per 1 SD increase in genetically predicted folate and vitamin B₆ levels were 0.49 (95% CI, 0.34–0.71; p = 1.3 × 10^–4) and 0.70 (95% CI, 0.52–0.94; p = 0.02), respectively. Genetically higher vitamin B₁₂ levels were not associated with any stroke subtype.

Interpretation

These findings suggest that any effect of homocysteine‐lowering treatment in preventing stroke will be confined to the SVS subtype. Whether genetic variants at or near the MTHFR and MUT genes influence SVS risk through pathways other than homocysteine levels and downstream effects require further investigation. Ann Neurol 2019;85:495–501

Homocysteine and age-associated disorders

There are numerous theories of aging, a process which still seems inevitable. Aging leads to cancer and multi-systemic disorders as well as chronic diseases. Decline in age- associated cellular functions leads to neurodegeneration and cognitive decline that affect the quality of life. Accumulation of damage, mutations, metabolic changes, failure in cellular energy production and clearance of altered proteins over the lifetime, and hyperhomocysteinemia, ultimately result in tissue degeneration. The decline in renal functions, nutritional deficiencies, deregulation of methionine cycle and deficiencies of homocysteine remethylation and transsulfuration cofactors cause elevation of homocysteine with advancing age. Abnormal accumulation of homocysteine is a risk factor of cardiovascular, neurodegenerative and chronic kidney disease. Moreover, approximately 50% of people, aged 65 years and older develop hypertension and are at a high risk of developing cardiovascular insufficiency and incurable neurodegenerative disorders. Increasing evidence suggests inverse relation between cognitive impairment, cerebrovascular and cardiovascular events and renal function. Oxidative stress, inactivation of nitric oxide synthase pathway and mitochondria dysfunction associated with impaired homocysteine metabolism lead to aging tissue degeneration. In this review, we examine impact of high homocysteine levels on changes observed with aging that contribute to development and progression of age associated diseases.

Advances in biomarkers of cerebral small vessel disease

Cerebral small vessel disease (CSVD) refers to a type of syndrome caused by lesions in perforating arteries, small veins, small arteries, or capillaries, resulting in clinical, imaging, or pathological alterations. The occurrence and development of CSVD are related to various cerebrovascular risk factors, such as metabolism and genetic factors. CSVD is diagnosed based on brain imaging biomarkers; however, biomarkers capable of predicting and diagnosing CSVD early in its progression have not been found. Exploring biomarkers closely related to disease progression is of great significance for early diagnosis, prognosis, prevention, and treatment of CSVD. This article examines the research progress of CSVD biomarkers, from inflammatory biomarkers, coagulation and fibrinolysis markers, biomarkers of endothelial dysfunction, biomarkers related to cerebrospinal fluid, and gene markers.

Age and recurrent stroke are related to the severity of white matter hyperintensities in lacunar infarction patients with diabetes

Background and purpose

White matter hyperintensities (WMH) is identified as a marker of cerebral small vessel diseases and is a major contributor to cognitive impairment, depression, gait disturbance, and urinary incontinence. However, the risk factors for WMH in patients with type 2 diabetes mellitus (T2DM) has not been well explored. Thus, in this study, we aimed to investigate the relationship between the severity of WMH and vascular risk factors in lacunar infarction patients with T2DM.

Methods

Consecutive lacunar infarction patients with T2DM were recruited in this cross-sectional study. Paraventricular WMH (P-WMH) and deep WMH (D-WMH) were separately scored by the Fazekas scale, and classified into two categories by the severity. Vascular risk factors and clinical features were compared between the mild and severe WMH. Multiple logistic regression analysis was used to determine the relationship between severity of WMH and vascular risk factors.

Results

A total of 327 participants aged 34–91 years were enrolled in this study. Compared with the patients with mild P-WMH, the patients with severe P-WMH had higher age (P=0.031), higher proportion of hypertension (P=0.042) and stroke (P<0.001). Levels of TG, LDL, and HbA1c were significantly higher in patients with mild P-WMH. Compared with the patients with mild D-WMH the patients with severe D-WMH had higher age and hyperhomocysteinemia (HCY) level (P<0.001), higher proportion of hyperlipidemia (P=0.008), and stroke (P<0.001). Multivariable logistic regression analyses showed that higher age and recurrent stroke were independently related to severe P-WMH and D-WMH in lacunar infarction patients with T2DM.

Conclusions

Age and recurrent stroke are related to the severity of P-WMH and D-WMH in lacunar infarction patients with T2DM.

Emodin Rescued Hyperhomocysteinemia-Induced Dementia and Alzheimer's Disease-Like Features in Rats

BACKGROUND

Hyperhomocysteinemia is an independent risk factor for dementia, including Alzheimer's disease. Lowering homocysteine levels with folic acid treatment with or without vitamin B12 has shown few clinical benefits on cognition.

METHODS

To verify the effect of emodin, a naturally active compound from Rheum officinale, on hyperhomocysteinemia-induced dementia, rats were treated with homocysteine injection (HCY, 400 μg/kg/d, 2 weeks) via vena caudalis. Afterwards, HCY rats with cognitive deficits were administered intragastric emodin at different concentrations for 2 weeks: 0 (HCY-E0), 20 (HCY-E20), 40 (HCY-E40), and 80 mg/kg/d (HCY-E80).

RESULTS

β-Amyloid overproduction, tau hyperphosphorylation, and losses of neuron and synaptic proteins were detected in the hippocampi of HCY-E0 rats with cognitive deficits. HCY-E40 and HCY-E80 rats had better behavioral performance. Although it did not reduce the plasma homocysteine level, emodin (especially 80 mg/kg/d) reduced the levels of β-amyloid and tau phosphorylation, decreased the levels of β-site amyloid precursor protein-cleaving enzyme 1, and improved the activity of protein phosphatase 2A. In the hippocampi of HCY-E40 and HCY-E80 rats, the neuron numbers, levels of synaptic proteins, and phosphorylation of the cAMP responsive element-binding protein at Ser133 were increased. In addition, depressed microglial activation and reduced levels of 5-lipoxygenase, interleukin-6, and tumor necrosis factor α were also observed. Lastly, hyperhomocysteinemia-induced microangiopathic alterations, oxidative stress, and elevated DNA methyltransferases 1 and 3β were rescued by emodin.

CONCLUSIONS

Emodin represents a novel potential candidate agent for hyperhomocysteinemia-induced dementia and Alzheimer's disease-like features.

Clinical and imaging characteristics of subacute combined degeneration complicated with white matter lesions in the brain: a report of five cases

PURPOSE

To report five cases of subacute combined degeneration (SCD) with brain involvement and explore its clinical and imaging characteristics.

METHODS

A retrospective study was performed on the clinical data and brain MRI of five patients with subacute combined degeneration with brain involvement (out of 107 cases with SCD in total). White matter lesions (WML) assessment was performed qualitatively using Fazekas scale score.

RESULTS

The main symptoms in four patients were weakness in both lower extremities and unstable walking (limb weakness in three patients, dizziness in three patients, and blurred vision in one patient). One patient had memory loss and cognitive dysfunction. The MMSE scale indicated mild dementia in one patient. On head MRI (Magnetic Resonance Imaging), multifocal and symmetrical high signals of T2WI and FLAIR were observed in the frontal lobe and periventricular white matter in four patients, while another patient showed preferential atrophy in frontal regions. Fazekas scale scores ranged from 1-6.

CONCLUSION

Adult subacute combined degeneration seldom involves the brain. Multifocal and symmetrical high signal white matter lesions can be found on FLAIR and T2WI, as well as frontal atrophy on head MRI.

Association between Homocysteine and Cerebral Small Vessel Disease: A Meta-Analysis

BACKGROUND

This study aimed to evaluate whether elevated homocysteine levels is associated with risk of different subtypes of cerebral small vessel disease (CSVD) by using meta-analysis.

MATERIALS AND METHODS

Electronic databases were systematically searched up to April 2018 for collecting the studies reporting homocysteine levels in CSVD or CSVD subtypes. After an inclusion and exclusion criteria, the data was extracted. All data was analyzed using Stata software v.12.0 (Stata Corp LP, College Station, TX). The standardized mean difference (SMD) and 95% confidence interval (CI) were used to compare continuous variables.

RESULTS

Eighteen studies met eligibility criteria with 5088 participants (1987 patients with CSVD and 3101 controls) included in the meta-analysis. Meta-analysis revealed that, compared with the controls group, the CSVD group had significantly higher homocysteine levels, with the SMD of .50 and 95% CI (.36-.64). Subgroup analyses suggested white matter lesion had significantly higher levels of homocysteine compared with controls (SMD = .56, 95% CI .39-.73), followed by silent brain infarction (SMD = .33, 95% CI .24-.42) and lacunar infarction (SMD = .17, 95% CI -.06 to .40).

CONCLUSIONS

This meta-analysis found that CSVD or CSVD subtypes have a significantly higher homocysteine levels than in controls. Further prospective population-based studies are needed to longitudinally evaluate the association between homocysteine levels and progression of different CSVD subtypes.

Diagnostic Values of Serum Levels of Homocysteine and Uric Acid for Predicting Vascular Mild Cognitive Impairment in Patients with Cerebral Small Vessel Disease

Background

This study aimed to investigate the diagnostic values of serum levels of Hcy and UA for predicting vascular mild cognitive impairment (VMCI) in patients with cerebral small vessel disease (SVD).

Material/Method

We selected 172 cerebral SVD patients and divided them into a VMCI group and a non-VMCI group. Eighty-six healthy individuals without nervous system diseases were selected as the control group. Enzymatic cycling method was performed to detect serum Hcy and UA levels. Serum levels of folic acid (FOA) and vitamin B12 (VitB12) were detected by chemiluminescence immunoassay. Montreal cognitive assessment (MoCA) was applied to evaluate the cognitive function. The ROC curve was used to evaluate the diagnostic values of serum Hcy and UA levels for predicting VMCI. Logistic regression analysis was used to determine the possible risk factors.

Results

Compared with the non-VMCI and control groups, serum FOA and VitB12 levels were lower and serum Hcy and UA levels were higher in the VMCI group. AUC values of serum Hcy and UA levels were 0.703 and 0.829, respectively. Serum Hcy and UA levels were negatively correlated with serum FOA and VitB12 levels, total MoCA score, and subscores on visuospatial ability and executive function, on language ability and on delayed recall, and they were positively correlated with serum cholesterol (CH) level. Serum Hcy and UA levels were indicated as risk factors for VMCI in cerebral SVD patients.

Conclusions

These results suggest that serum Hcy and UA levels may serve as predictive factors for VMCI in cerebral SVD patients.

The association of uric acid with leukoaraiosis

Objective

To explore the possible correlation between uric acid levels and leukoaraiosis (LA).

Methods

This cross-sectional study enrolled patients who presented with some neurological discomfort (e.g. dizziness, headache, mild cognitive impairment). Potential demographic and clinical risk factors associated with LA, including sex, age, hypertension, diabetes mellitus, smoking, alcohol consumption, dyslipidaemia, plasma fibrinogen, D-dimer, uric acid, and homocysteine, were investigated using univariate and multivariate logistic regression analyses.

Results

A total of 268 patients were enrolled in the study and divided into the LA group (n = 164) and the non-LA group (n = 104). Compared with the non-LA group, uric acid was significantly higher in the LA group (mean ± SD: 356.49 ± 121.85 µmol/l versus 289.96 ± 102.98 µmol/l). Multivariate logistic regression analyses showed that uric acid was an independent risk factor for LA (odds ratio 1.285; 95% confidence interval 1.062, 1.556).

Conclusion

Hyperuricaemia was an independent risk factor for leukoaraiosis in Chinese patients.

Homocysteine, Alcoholism, and Its Potential Epigenetic Mechanism

Alcohol is the most socially accepted addictive drug. Alcohol consumption is associated with some health problems such as neurological, cognitive, behavioral deficits, cancer, heart, and liver disease. Mechanisms of alcohol-induced toxicity are presently not yet clear. One of the mechanisms underlying alcohol toxicity has to do with its interaction with amino acid homocysteine (Hcy), which has been linked with brain neurotoxicity. Elevated Hcy impairs with various physiological mechanisms in the body, especially metabolic pathways. Hcy metabolism is predominantly controlled by epigenetic regulation such as DNA methylation, histone modifications, and acetylation. An alteration in these processes leads to epigenetic modification. Therefore, in this review, we summarize the role of Hcy metabolism abnormalities in alcohol-induced toxicity with epigenetic adaptation and their influences on cerebrovascular pathology.

Elevated homocysteine levels contribute to larger hematoma volume in patients with intracerebral hemorrhage

BACKGROUND

We investigate whether plasma homocysteine (HCY) levels are associated with hematoma volume and outcome in patients with intracerebral hemorrhage (ICH).

METHODS

A total of 69 patients admitted within 24 hours after ICH onset was divided into 2 groups based on admission plasma HCY levels (low homocysteinemia [LHCY] group, plasma HCY concentrations ≤14.62 μmol/L, versus high homocysteinemia [HHCY] group, >14.62 μmol/L).

RESULTS

Mean hematoma volumes for 2 groups (LHCY and HHCY) were 13.18 and 23.09 mL (P = .012), respectively, in patients with thalamoganglionic ICH, but hematoma volumes between 2 groups had no significant difference among patients with lobar or infratentorial ICH. On multivariate linear regression analysis, elevated HCY levels significantly correlated with larger hematoma volume in patients with thalamoganglionic ICH (B = .604, P = .004) after adjustment for confounding factors. Poor outcomes (6-month modified Rankin Scale scores ≥3) were not significantly different between 2 groups (low homocysteinemia group, 31.4%, versus high homocysteinemia group, 41.2%, P = .400).

CONCLUSIONS

Elevated plasma HCY levels were associated with larger hematoma volume only in patients with thalamoganglionic ICH. HCY levels might not be predictors of the 6-month clinical outcome in patients with ICH.

Camk2b protects neurons from homocysteine-induced apoptosis with the involvement of HIF-1α signal pathway

In our previous study using iTRAQ technique we found that the level of calmodulin-dependent protein kinase 2b (Camk2b) was lower in rats with hyperhomocysteinemia. We presumed that Camk2b might be involved in homocysteine-induced apoptosis and tried to explore its role in this study through the transfection with Camk2b gene. Results showed that neurons of HHcy group had lower activity measured by MTT, higher percentage of apoptotic neurons, lower expression levels of Camk2b mRNA and protein than those in normal group. Neurons with overexpression of Camk2b (Camk2b group) had lower percentage of apoptosis and higher activity than those in control group. After exposure to 2-Methoxyestradiol, the activity of neurons with overexpression of Camk2b was suppressed with more apoptotic cells observed. The expressions of BCL2, eNOS, EP300 and EPO were all elevated at both mRNA and protein levels in neurons of CamK2b group compared with other three groups. Thus, Camk2b protects neurons from Homocysteine-induced apoptosis with the involvement of HIF-1α signal pathway.

Small vessel disease and memory loss: what the clinician needs to know to preserve patients' brain health

Small vessel disease (SVD) in the brain manifests in the periventricular and deep white matter and radiographically is described as "leukoaraiosis". It is increasingly recognized as a cause of morbidity from middle age onward and this clinical relevance has paralleled advances in the field of neuroradiology. Overall, SVD is a heterogenous group of vascular disorders that may be asymptomatic, or a harbinger of many conditions that jeopardize brain health. Management and prevention focuses on blood pressure control, lifestyle modification, and symptomatic treatment.

Intravital imaging in spontaneously hypertensive stroke-prone rats-a pilot study

Background

There is growing evidence that endothelial failure and subsequent blood brain barrier (BBB) breakdown initiate cerebral small vessel disease (CSVD) pathology. In spontaneously hypertensive stroke-prone rats (SHRSP) endothelial damage is indicated by intraluminal accumulations of erythrocytes (erythrocyte thrombi) that are not observed with current magnetic resonance imaging techniques. Two-photon microscopy (2 PM) offers the potential for real-time direct detection of the small vasculature. Thus, within this pilot study we investigated the sensitivity of 2 PM to detect erythrocyte thrombi expressing initiating CSVD phenomena in vivo.

Methods

Eight SHRSP and 13 Wistar controls were used for in vivo imaging and subsequent histology with haematoxylin-eosin (HE). For 2 PM, cerebral blood vessels were labeled by fluorescent Dextran (70 kDa) applied intraorbitally. The correlation between vascular erythrocyte thrombi observed by 2 PM and HE-staining was assessed. Artificial surgical damage and parenchymal Dextran distribution were analyzed postmortem.

Results

Dextran was distributed within the small vessel walls and co-localized with IgG.

Artificial surgical damage was comparable between SHRSP and Wistar controls and mainly affected the small vasculature. In fewer than 20% of animals there was correlation between erythrocyte thrombi as observed with 2 PM and histologically with HE.

Conclusions

Contrary to our initial expectations, there was little agreement between intravital 2 PM imaging and histology for the detection of erythrocyte thrombi. Two-photon microscopy is a valuable technique that complements but does not replace the value of conventional histology.

Potential serum biomarkers in the pathophysiological processes of stroke

Stroke is a leading cause of death and serious long-term disability. Ischemic stroke is the major subtype of stroke. Currently, its diagnosis is mainly dependent upon clinical symptoms and neuroimaging techniques. Despite these clinical and imaging modalities, often strokes are not recognized after initial onset. As early intervention of medical or surgical therapy is often associated with improved outcomes, there is an urgent need to improve the speed and accuracy of stroke diagnosis. Stroke is a complex pathophysiological process involving; energy failure, imbalance of ion homeostasis, acidosis, intracellular calcium overload, neuronal excitotoxicity, free radical-mediated lipid oxidation, inflammatory cell infiltration, and glial cell activation. These events ultimately lead to neuronal apoptotic cell death or necrosis. In this review, we have summarized the serum biomarkers according to the pathophysiological processes of stroke, which have been intensively studied in clinical trials of stroke over the past five years, and also used Medline's 'related article' option to identify further articles. We focused on the potential biomarkers pertaining to vascular injury, metabolic changes, oxidative injury, and inflammation, and newly studied biomarkers, and discussed how these biomarkers could be used for the diagnosis or determining the prognosis of stroke.