Genetic risk of Spontaneous intracerebral hemorrhage: Systematic review and future directions

Key biomarkers in cerebral arteriovenous malformations: Updated review

The formation of vascular networks consisting of arteries, capillaries, and veins is vital in embryogenesis. It is also crucial in adulthood for the formation of a functional vasculature. Cerebral arteriovenous malformations (CAVMs) are linked with a remarkable risk of intracerebral hemorrhage because arterial blood is directly shunted into the veins before the arterial blood pressure is dissipated. The underlying mechanisms responsible for arteriovenous malformation (AVM) growth, progression, and rupture are not fully known, yet the critical role of inflammation in AVM pathogenesis has been noted. The proinflammatory cytokines are upregulated in CAVM, which stimulates overexpression of cell adhesion molecules in endothelial cells (ECs), leading to improved leukocyte recruitment. It is well-known that metalloproteinase-9 secretion by leukocytes disrupts CAVM walls resulting in rupture. Moreover, inflammation alters the angioarchitecture of CAVMs by upregulating angiogenic factors impacting the apoptosis, migration, and proliferation of ECs. A better understanding of the molecular signature of CAVM might allow us to identify biomarkers predicting this complication, acting as a goal for further investigations that may be potentially targeted in gene therapy. The present review is focused on the numerous studies conducted on the molecular signature of CAVM and the associated hemorrhage. The association of numerous molecular signatures with a higher risk of CAVM rupture is shown through inducing proinflammatory mediators, as well as growth factors signaling, Ras-mitogen-activated protein kinase-extracellular signal-regulated kinase, and NOTCH pathways, which are accompanied by cellular level inflammation and endothelial alterations resulting in vascular wall instability. According to the studies, it is assumed that matrix metalloproteinase, interleukin-6, and vascular endothelial growth factor are the biomarkers most associated with CAVM and the rate of hemorrhage, as well as diagnostic methods, with respect to enhancing the patient-specific risk estimation and improving treatment choices.

Mood swings are causally associated with intracranial aneurysm subarachnoid hemorrhage: A Mendelian randomization study

BACKGROUND

Mood swings have been observed in patients with intracranial aneurysm (IA), but it is still unknown whether mood swings can affect IA.

AIM

To explore the causal association between mood swings or experiencing mood swings and IA through a two-sample Mendelian randomization (MR) study.

METHODS

Summary-level statistics of mood swings, experiencing mood swings, IA, aneurysm-associated subarachnoid hemorrhage (aSAH), and non-ruptured IA (uIA) were collected from the genome-wide association study. Two-sample MR and various sensitivity analyses were employed to explore the causal association between mood swings or experiencing mood swings and IA, or aSAH, or uIA. The inverse-variance weighted method was used as the primary method.

RESULTS

Genetically determined mood swings (odds ratio [OR] = 5.23, 95% confidence interval (95%CI): 1.65-16.64, p = .005) and experiencing mood swings (OR = 2.50, 95%CI: 1.37-4.57, p = .003) were causally associated with an increased risk of IA. Mood swings (OR = 5.67, 95%CI: 1.40-23.04, p = .015) and experiencing mood swings were causally associated with the risk of aSAH (OR = 2.91, 95%CI: 1.47-5.75, p = .002). Neither mood swings (OR = 1.95, 95%CI: .31-12.29, p = .478) nor experiencing mood swings (OR = 1.20, 95%CI: .48-3.03, p = .693) were associated with uIA.

CONCLUSIONS

Mood swings and experiencing mood swings increased the risk of IA and aSAH incidence. These results suggest that alleviating mood swings may reduce IA rupture incidence and aSAH incidence.

Association between gut microbiome and intracerebral hemorrhage based on genome-wide association study data

OBJECTIVES

Intracerebral hemorrhage (ICH) has the highest mortality and disability rates among various subtypes of stroke. Previous studies have shown that the gut microbiome (GM) is closely related to the risk factors and pathological basis of ICH. This study aims to explore the causal effect of GM on ICH and the potential mechanisms.

METHODS

Genome wide association study (GWAS) data on GM and ICH were obtained from Microbiome Genome and International Stroke Genetics Consortium. Based on the GWAS data, we first performed Mendelian randomization (MR) analysis to evaluate the causal association between GM and ICH. Then, a conditional false discovery rate (cFDR) method was conducted to identify the pleiotropic variants.

RESULTS

MR analysis showed that Pasteurellales, Pasteurellaceae, and Haemophilus were negatively correlated with the risk of ICH, whileVerrucomicrobiae, Verrucomicrobiales, Verrucomicrobiaceae, Akkermansia, Holdemanella, and LachnospiraceaeUCG010 were positively correlated with ICH. By applying the cFDR method, 3 pleiotropic loci (rs331083, rs4315115, and rs12553325) were found to be associated with both GM and ICH.

CONCLUSIONS

There is a causal association and pleiotropic variants between GM and ICH.

A Genomic Risk Score Identifies Individuals at High Risk for Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) has an estimated heritability of 29%. We developed a genomic risk score for ICH and determined its predictive power in comparison to standard clinical risk factors.

METHODS

We combined genome-wide association data from individuals of European ancestry for ICH and related traits in a meta-genomic risk score ([metaGRS]; 2.6 million variants). We tested associations with ICH and its predictive performance in addition to clinical risk factors in a held-out validation dataset (842 cases and 796 controls). We tested associations with risk of incident ICH in the population-based UK Biobank cohort (486 784 individuals, 1526 events, median follow-up 11.3 years).

RESULTS

One SD increment in the metaGRS was significantly associated with 31% higher odds for ICH (95% CI, 1.16-1.48) in age-, sex- and clinical risk factor-adjusted models. The metaGRS identified individuals with almost 5-fold higher odds for ICH in the top score percentile (odds ratio, 4.83 [95% CI, 1.56-21.2]). Predictive models for ICH incorporating the metaGRS in addition to clinical predictors showed superior performance compared to the clinical risk factors alone (c-index, 0.695 versus 0.686). The metaGRS showed similar associations for lobar and nonlobar ICH, independent of the known APOE risk locus for lobar ICH. In the UK Biobank, the metaGRS was associated with higher risk of incident ICH (hazard ratio, 1.15 [95% CI, 1.09-1.21]). The associations were significant within both a relatively high-risk population of antithrombotic medications users, as well as among a relatively low-risk population with a good control of vascular risk factors and no use of anticoagulants.

CONCLUSIONS

We developed and validated a genomic risk score that predicts lifetime risk of ICH beyond established clinical risk factors among individuals of European ancestry. Whether implementation of the score in risk prognostication models for high-risk populations, such as patients under antithrombotic treatment, could improve clinical decision making should be explored in future studies.

A systematic review and meta-analysis expounding the relationship between methylene tetrahydrofolate reductase gene polymorphism and the risk of intracerebral hemorrhage among populations

Background: The relationship between methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphism with the risk of intracerebral hemorrhage (ICH) has remained to be controversial in recent years. This meta-analysis is aimed to confirm the association of these.

Methods: Systematically searching the related studies from the PubMed, Embase, Cochrane Library, China national knowledge internet database from 1 January 1990 to 1 June 2022. The odd ratio (ORs) and 95% confidence interval (CIs) of gene-disease correlation in various gene models were calculated by fixed or random effect model of meta-analysis. We included 20 case-control studies in this meta-analysis with a total of 1,989 ICH patients and 4,032 health controls originated from Asian, Caucasian, and African populations.

Results: The statistical analysis demonstrated the association of MTHFR C677T gene polymorphism with ICH in allele model [OR_{T VS. C} = 1.20 (95%CI: 1.06–1.36)]; homozygote model [OR _{TT VS. CC} = 1.50 (95%CI: 1.20–1.88)]; dominant model [OR _{CT+ TT VS. CC} = 1.23 (95%CI: 1.03–1.48)] and recessive model [OR_{TT VS. CT+CC} = 1.37 (95%CI: 1.17–1.60)]. Besides, we also found the relationship of MTHFR C677T gene polymorphism with Asian in four comparison model (OR_{T VS. C} = 1.19.95%CI:1.09–1.37, OR_{TT VS. CC} = 1.46.95%CI: 1.15–1.85, OR _{CT+ TT VS. CC} = 1.25.95%CI: 1.01–1.54, OR_{TT VS. CT+CC} = 1.34.95%CI: 1.54–1.17) and Caucasian in four comparison model (OR_{T VS. C} = 1.90.95%CI: 1.22–2.97, OR_{TT VS. CC} = 2.67.95%CI: 1.42–5.00, OR _{CT+ TT VS. CC} = 1.56.95%CI: 1.05–2.32, OR_{TT VS. CT+CC} = 2.25.95%CI: 1.46–4.00). But no statistically significant correlation between A1298C polymorphism and the occurrence of ICH was detected in four studies.

Conclusion: MTHFR C677T gene polymorphism increases the risk of ICH in Asian and Caucasian populations but has no impact on the incidence in African communities. More importantly, the risk of ICH increases in TT genotype individuals in comparison to CT and CC genotype individuals in Asian and Caucasian populations.

Human Galectin-7 Gene LGALS7 Promoter Sequence Polymorphisms and Risk of Spontaneous Intracerebral Hemorrhage: A Prospective Study

Background and purpose

Despite evidence for the role of genetic factors in stroke, only a small proportion of strokes have been clearly attributed to monogenic factors, due to phenotypic heterogeneity. The goal of this study was to determine whether a significant relationship exists between human galectin-7 gene LGALS7 promoter region polymorphisms and the risk of stroke due to non-traumatic intracerebral hemorrhage (ICH).

Methods

This two-stage genetic association study included an initial exploratory stage followed by a discovery stage. During the exploratory stage, transgenic galectin-7 mice or transgenic mice with the scrambled sequence of the hairpin structure –silenced down gene LGALS7—were generated and then expressed differentially expressed proteins and galectin-7-interacting proteins were identified through proteomic analysis. During the discovery stage, a single-nucleotide polymorphism (SNP) genotyping approach was used to determine associations between 2 LGALS7 SNPs and ICH stroke risk for a cohort of 24 patients with stroke of the Chinese Han population and 70 controls.

Results

During the exploratory phase, LGALS7 expression was found to be decreased in TGLGALS–DOWN mice as compared to its expression in TGLGALS mice. During the discovery phase, analysis of LGALS7 sequences of 24 non-traumatic ICH cases and 70 controls led to the identification of 2 ICH susceptibility loci: a genomic region on 19q13.2 containing two LGALS7 SNPs, rs567785577 and rs138945880, whereby the A allele of rs567785577 and the T allele of rs138945880 were associated with greater risk of contracting ICH [for T and A vs. C and G, unadjusted odds ratio (OR) = 13.5; 95% CI = 2.249–146.5; p = 0.002]. This is the first study to genotype the galectin-7 promoter in patients with hemorrhagic stroke. Genotype and allele association tests and preliminary analysis of patients with stroke revealed that a single locus may be a genetic risk factor for hemorrhagic stroke.

Conclusion

A and T alleles of two novel SNP loci of 19q13.2, rs567785577 and rs138945880, respectively, were evaluated for associations with susceptibility to ICH. Further studies with expanded case numbers that include subjects of other ethnic populations are needed to elucidate mechanisms underlying associations between these SNPs and ICH risk.

Tobacco Use: A Major Risk Factor of Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage (sICH) is one of the deadliest subtypes of stroke, and no treatment is currently available. One of the major risk factors is tobacco use. In this article, we review literature on how tobacco use affects the risk of sICH and also summarize the known effects of tobacco use on outcomes following sICH. Several studies demonstrate that the risk of sICH is higher in current cigarette smokers compared to non-smokers. The literature also establishes that cigarette smoking not only increases the risk of sICH but also increases hematoma growth, results in worse outcomes, and increases the risk of death from sICH. This review also discusses potential mechanisms activated by tobacco use which result in an increase in risk and severity of sICH. Exploring the underlying mechanisms may help alleviate the risk of sICH in tobacco users as well as may help better manage tobacco user sICH patients.