Novel functional insights into ischemic stroke biology provided by the first genome-wide association study of stroke in indigenous Africans.

BACKGROUND: African ancestry populations have the highest burden of stroke worldwide, yet the genetic basis of stroke in these populations is obscure. The Stroke Investigative Research and Educational Network (SIREN) is a multicenter study involving 16 sites in West Africa. We conducted the first-ever genome-wide association study (GWAS) of stroke in indigenous Africans. METHODS: Cases were consecutively recruited consenting adults (aged > 18 years) with neuroimaging-confirmed ischemic stroke. Stroke-free controls were ascertained using a locally validated Questionnaire for Verifying Stroke-Free Status. DNA genotyping with the H3Africa array was performed, and following initial quality control, GWAS datasets were imputed into the NIH Trans-Omics for Precision Medicine (TOPMed) release2 from BioData Catalyst. Furthermore, we performed fine-mapping, trans-ethnic meta-analysis, and in silico functional characterization to identify likely causal variants with a functional interpretation. RESULTS: We observed genome-wide significant (P-value < 5.0E-8) SNPs associations near AADACL2 and miRNA (MIR5186) genes in chromosome 3 after adjusting for hypertension, diabetes, dyslipidemia, and cardiac status in the base model as covariates. SNPs near the miRNA (MIR4458) gene in chromosome 5 were also associated with stroke (P-value < 1.0E-6). The putative genes near AADACL2, MIR5186, and MIR4458 genes were protective and novel. SNPs associations with stroke in chromosome 2 were more than 77 kb from the closest gene LINC01854 and SNPs in chromosome 7 were more than 116 kb to the closest gene LINC01446 (P-value < 1.0E-6). In addition, we observed SNPs in genes STXBP5-AS1 (chromosome 6), GALTN9 (chromosome 12), FANCA (chromosome 16), and DLGAP1 (chromosome 18) (P-value < 1.0E-6). Both genomic regions near genes AADACL2 and MIR4458 remained significant following fine mapping. CONCLUSIONS: Our findings identify potential roles of regulatory miRNA, intergenic non-coding DNA, and intronic non-coding RNA in the biology of ischemic stroke. These findings reveal new molecular targets that promise to help close the current gaps in accurate African ancestry-based genetic stroke's risk prediction and development of new targeted interventions to prevent or treat stroke.

Research participants' perception of ethical issues in stroke genomics and neurobiobanking research in Africa.

Background: There is a growing interest in stroke genomics and neurobiobanking research in Africa. These raise several ethical issues, such as consent, re-use, data sharing, storage, and incidental result of biological samples. Despite the availability of ethical guidelines developed for research in Africa, there is paucity of information on how the research participants' perspectives could guide the research community on ethical issues in stroke genomics and neurobiobanking research. To explore African research participants' perspectives on these issues, a study was conducted at existing Stroke Investigation Research and Education Network (SIREN) sites in Nigeria and Ghana. Method: Using an exploratory design, twenty-eight Focus Group Discussions (FGDs) sessions were conducted with stroke survivors (n=7), caregivers(n=7), stroke - free controls(n=7), and Community Advisory Board members(n=7). Data were collected using an interview guide. Interviews were conducted in English and indigenous languages of the community, audio recorded, and transcribed verbatim. Data were analyzed using NVivo (March, 2020) Software. Result: Results revealed that stroke genomics and neurobiobanking research in Africa require researchers' direct attention to ethical issues. Concerns were raised about understanding, disclosure and absence of coercion as components of true autonomous decision making in research participation. Participants argued that the risk and benefits attached to participation should be disclosed at the time of recruitment. Fears around data sharing were voiced as adherence to the principle of privacy and confidentiality were of paramount importance to participants. The preference was to receive the results of incidental findings with no stigma attached from society. Conclusion: Research participants' perspectives are a vital aspect of community engagement in stroke genomics and neurobiobanking research. Findings from this study suggest that research participants are interested in these fields of research in Africa if their concerns about ethical issues are appropriately addressed within the research framework.

Organized multi-disciplinary stroke team care improves acute stroke outcomes in resource limited settings; Results of a retrospective study from a Nigerian tertiary hospital.

BACKGROUND: Evidence for the impact of organized stroke multidisciplinary teams (MDTs) on outcomes in Africa is sparse. AIM: To compare stroke outcomes, before and after the establishment (September 16, 2016) of a pioneer MDT at a tertiary hospital in southern Nigeria. METHODS: Using a retrospective, observational study design, the in-patient record of all stroke patients admitted between September 2014 to September 2018 was retrieved and rigorously reviewed. 155 patients seen 2 years before the MDT were compared with 169 stroke patients seen 2 years after the MDT. Stroke severity at admission and functioning at discharge were assessed using the Stroke Levity Scale (SLS) and the modified Rankin scale (mRS). RESULTS: Mean ages (in years) were 60 pre-MDT vs 59.57 post MDT (p = 0.754). There were more males, 51% pre-MDT vs 54.2% post MDT (p = 0.565). SLS and mRS were not significantly different; severe SLS and mRS pre-MDT, 52.9% vs post-MDT, 49.4% (p = 0.727) and pre-MDT 19.4% vs post-MDT 19.5% (p = 0.685) respectively. More post-MDT patients were discharged alive, pre-MDT,56.8% vs 79.2% post MDT (p < 0.001); had swallow tests, pre-MDT 9.23% vs post-MDT 33.5% (p < 0.001); on secondary prevention, pre-MDT 67.7% vs post-MDT 78.9% (p = 0.023); had more clinic visits, pre-MDT,0.7% vs post-MDT 38.3% (p < 0.001). MDT was independently associated with lower in-hospital mortality on multivariable regression, adjusted odds ratio (OR) (95% Confidence interval CI) 0.17 (0.09-0.32). CONCLUSION: Our results suggest that an organized MDT may improve acute outcomes and reduce mortality in resource constrained settings where there may be no stroke units. These findings need further prospective validation.

Capacity-Building for Stroke Genomic Research Data Collection: The African Neurobiobank Ethical, Legal, and Social Implications Project Experience.

Background: The fields of stroke genomics, biobanking, and precision medicine are rapidly expanding in sub-Saharan Africa. However, the ethical, legal, and social implications (ELSI) of emerging neurobiobanking and genomic data resources are unclear in an emerging African scientific landscape with unique cultural, linguistic, and belief systems. Objective: This article documents capacity-building experiences of researchers during the development, pretesting, and validation of data collection instruments of the African Neurobiobank for Precision Stroke Medicine-(ELSI) Project. Methods: The African Neurobiobank for Precision Stroke Medicine-ELSI project is a transnational, multicenter project implemented across seven sites in Ghana and Nigeria. Guided by the Community-Based Participatory Research framework, we conducted three workshops with key stakeholders to review the study protocol, ensure uniformity in implementation; pretest, harmonize, and integrate context-specific feedback to ensure validity and adaptability of data collection instruments. Workshop impact was assessed using an open-ended questionnaire, which included questions on experience with participation in any of the workshops, building capacity in Genetic and Genomic Research (GGR), level of preparedness toward GGR, the genomic mini-dictionary developed by the team, and its impact in enhancing understanding in GGR. Data were analyzed qualitatively using a thematic framework approach. Results: Findings revealed the usefulness of the workshop in improving participants' knowledge and capacity toward GGR implementation. It further identified local, context-specific concerns regarding quality data collection, the need to develop culturally acceptable, genomic/biobanking data collection tools, and a mini-dictionary. Participants-reported perceptions were that the mini-dictionary enhanced understanding, participation, and data collection in GGR. Overall, participants reported increased preparedness and interest in participating in GGR. Conclusion: Capacity-building is a necessary step toward ELSI-related genomic research implementation in African countries where scholarship of ELSI of genomics research is emerging. Our findings may be useful to the design and implementation of ELSI-GGR projects in other African countries.

Frequency and factors associated with post-stroke seizures in a large multicenter study in West Africa.

BACKGROUND: Post-stroke seizures (PSS) are associated with significant morbidity and mortality across the globe. There is a paucity of data on PSS in Africa. PURPOSE: To assess the frequency and factors associated with PSS by stroke types across 15 hospitals in Nigeria and Ghana. METHODS: We analyzed data on all stroke cases recruited into the Stroke Investigative Research and Educational Network (SIREN). We included adults aged ≥18 years with radiologically confirmed ischemic stroke (IS) or intracerebral hemorrhage (ICH). PSS were defined as acute symptomatic seizures occurring at stroke onset and/or during acute hospitalization up until discharge. We used logistic regression to estimate adjusted odds ratios (aOR) with 95% Confidence Interval. RESULTS: Among 3344 stroke patients, 499 (14.9%) had PSS (95% CI: 13.7-16.2%). The mean duration of admission in days for those with PSS vs no PSS was 17.4 ± 28.6 vs 15.9 ± 24.7, p = 0.72. There were 294(14.1%) PSS among 2091 ischemic strokes and 159(17.7%) among 897 with ICH, p = 0.01. The factors associated with PSS occurrence were age < 50 years, aOR of 1.59 (1.08-2.33), National Institute of Health Stroke Score (NIHSS), 1.29 (1.16-1.42) for each 5 units rise and white cell count 1.07 (1.01-1.13) for each 10^3 mm3 rise. Factors associated with PSS in ischemic were NIHSS score, aOR of 1.17 (1.04-1.31) and infarct volume of 10-30 cm3 aOR of 2.17(1.37-3.45). Among ICH, associated factors were alcohol use 5.91 (2.11-16.55) and lobar bleeds 2.22 (1.03-4.82). CONCLUSION: The burden of PSS among this sample of west Africans is substantial and may contribute to poor outcomes of stroke in this region. Further longitudinal studies are required to understand the impact on morbidity and mortality arising from PSS in Africa.

Unraveling the risk factors for spontaneous intracerebral hemorrhage among West Africans.

OBJECTIVE: To characterize risk factors for spontaneous intracerebral hemorrhage (sICH) occurrence and severity among West Africans. METHODS: The Stroke Investigative Research and Educational Network (SIREN) study is a multicenter case-control study involving 15 sites in Ghana and Nigeria. Patients were adults ≥18 years old with CT-confirmed sICH with age-, sex-, and ethnicity-matched stroke-free community controls. Standard instruments were used to assess vascular, lifestyle, and psychosocial factors. Factors associated with sICH and its severity were assessed using conditional logistic regression to estimate odds ratios (ORs) and population-attributable risks (PARs) with 95% confidence intervals (CIs) for factors. RESULTS: Of 2,944 adjudicated stroke cases, 854 were intracerebral hemorrhage (ICH). Mean age of patients with ICH was 54.7 ± 13.9 years, with a male preponderance (63.1%), and 77.3% were nonlobar. Etiologic subtypes of sICH included hypertension (80.9%), structural vascular anomalies (4.0%), cerebral amyloid angiopathy (0.7%), systemic illnesses (0.5%), medication-related (0.4%), and undetermined (13.7%). Eight factors independently associated with sICH occurrence by decreasing order of PAR with their adjusted OR (95% CI) were hypertension, 66.63 (20.78-213.72); dyslipidemia, 2.95 (1.84-4.74); meat consumption, 1.55 (1.01-2.38); family history of CVD, 2.22 (1.41-3.50); nonconsumption of green vegetables, 3.61 (2.07-6.31); diabetes mellitus, 2.11 (1.29-3.46); stress, 1.68 (1.03-2.77); and current tobacco use, 14.27 (2.09-97.47). Factors associated with severe sICH using an NIH Stroke Scale score >15 with adjusted OR (95% CI) were nonconsumption of leafy green vegetables, 2.03 (1.43-2.88); systolic blood pressure for each mm Hg rise, 1.01 (1.00-1.01); presence of midline shift, 1.54 (1.11-2.13); lobar ICH, 1.72 (1.16-2.55); and supratentorial bleeds, 2.17 (1.06-4.46). CONCLUSIONS: Population-level control of the dominant factors will substantially mitigate the burden of sICH in West Africa.

Unraveling the Ethical, Legal, and Social Implications of Neurobiobanking and Stroke Genomic Research in Africa: A Study Protocol of the African Neurobiobank for Precision Stroke Medicine ELSI Project.

The ethical, legal, and social implications (ELSI) of emerging neurobiobanks and data resources are unclear in an African scientific landscape with unique cultural, linguistic, and belief systems. The overarching goal of the African Neurobiobank for Precision Stroke Medicine-ELSI Project is to identify, examine, and develop novel approaches to address ELSI issues of biobanking and stroke genomic research in sub-Saharan Africa (SSA). To accomplish the goal we will (1) explore knowledge, attitude, perceptions, barriers, and facilitators influencing ELSI issues related to biobanking and stroke genomic research; (2) use information obtained to craft a community intervention program focused on ELSI issues; and (3) build capacity and careers related to genomics and biobanking for effective client/community engagement while enhancing regulatory, governance, and implementation competences in biobanking science in SSA. A community-based participatory research and mixed-methodological approach, focused on various levels of the social ecological model, will be used to identify and examine relevant ELSI issues. Contextual intervention tools, platforms, and practices will be developed to enhance community understanding and participation in stroke biobanking and genomics research activities while facilitating enduring trust, and equitable and fair utilization of biobanking resources for genetic and trans-omics research. A concurrent capacity building program related to genetic counseling and biobanking will be implemented for early career researchers. The huge potential for neurobiobanking and genomics research in Africa to advance precision medicine applicable to stroke and other neurological disorders requires addressing ELSI challenges while building sustainable research, career, and regulatory capacities in trans-omics and biobanking science.

Knowledge, attitudes and practices of West Africans on genetic studies of stroke: Evidence from the SIREN Study.

BACKGROUND: It is crucial to assess genomic literacy related to stroke among Africans in preparation for the ethical, legal and societal implications of the genetic revolution which has begun in Africa. OBJECTIVE: To assess the knowledge, attitudes and practices (KAP) of West Africans about stroke genetic studies. METHODS: A comparative cross-sectional study was conducted among stroke patients and stroke-free controls recruited across 15 sites in Ghana and Nigeria. Participants' knowledge of heritability of stroke, willingness to undergo genetic testing and perception of the potential benefits of stroke genetic research were assessed using interviewer-administered questionnaire. Descriptive, frequency distribution and multiple regression analyses were performed. RESULTS: Only 49% of 2029 stroke patients and 57% of 2603 stroke-free individuals knew that stroke was a heritable disorder. Among those who knew, 90% were willing to undergo genetic testing. Knowledge of stroke heritability was associated with having at least post-secondary education (OR 1.51, 1.25-1.81) and a family history of stroke (OR 1.20, 1.03-1.39) while Islamic religion (OR=0.82, CI: 0.72-0.94), being currently unmarried (OR = 0.81, CI: 0.70-0.92), and alcohol use (OR = 0.78, CI: 0.67-0.91) were associated with lower odds of awareness of stroke as a heritable disorder. Willingness to undergo genetic testing for stroke was associated with having a family history of stroke (OR 1.34, 1.03-1.74) but inversely associated with a medical history of high blood pressure (OR = 0.79, 0.65-0.96). CONCLUSION: To further improve knowledge of stroke heritability and willingness to embrace genetic testing for stroke, individuals with less formal education, history of high blood pressure and no family history of stroke require targeted interventions.

Biobanking in a Challenging African Environment: Unique Experience from the SIREN Project.

Africa was previously insufficiently represented in the emerging discipline of biobanking despite commendable early efforts. However, with the Human, Heredity, and Health in Africa (H3Africa) initiative, biorepository science has been bolstered, regional biobanks are springing up, and awareness about biobanks is growing on the continent. The Stroke Investigative Research and Educational Network (SIREN) project is a transnational, multicenter, hospital and community-based study involving over 3000 cases and 3000 controls recruited from 16 sites in Ghana and Nigeria. SIREN aims to explore and unravel the genetic and environmental factors that interact to produce the peculiar phenotypic and clinical characteristics of stroke as seen in people of African ancestry and facilitate the development of new diagnostics, therapeutics, and preventative strategies. The aim of this article is to describe our experience with the development of the procedure for collection, processing, storage, and shipment of biological samples (blood, serum, plasma, buffy coat, red cell concentrates, and DNA) and brain imaging across coordinating and participating sites within the SIREN Project. The SIREN network was initiated in 2014 with support and funding from the H3Africa Initiative. The SIREN Biobank currently has 3015 brain images, 92,950 blood fractions (serum, plasma, red cell concentrates, and buffy coat) accrued from 8450 recruited subjects, and quantified and aliquoted good-quality DNA extracts from 6150 study subjects. This represents an invaluable resource for future research with expanding genomic and trans-omic technologies. This will facilitate the involvement of indigenous African samples in cutting-edge stroke genomics and trans-omics research. It is, however, critical to effectively engage African stroke patients and community members who have contributed precious biological materials to the SIREN Biobank to generate appropriate evidence base for dealing with ethical, legal, and social issues of privacy, autonomy, identifiability, biorights, governance issues, and public understanding of stroke biobanking in the context of unique African culture, language, and belief systems.