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Introduction: Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, yet our comprehension predominantly relies on studies within the non-Hispanic White (NHW) population. Here we aimed to provide comprehensive insights into the proteomic landscape of AD across diverse racial and ethnic groups. Methods: Dorsolateral prefrontal cortex (DLPFC) and superior temporal gyrus (STG) brain tissues were donated from multiple centers (Mayo Clinic, Emory University, Rush University, Mt. Sinai School of Medicine) and were harmonized through neuropathological evaluation, specifically adhering to the Braak staging and CERAD criteria. Among 1105 DLPFC tissue samples (998 unique individuals), 333 were from African American donors, 223 from Latino Americans, 529 from NHW donors, and the rest were from a mixed or unknown racial background. Among 280 STG tissue samples (244 unique individuals), 86 were African American, 76 Latino American, 116 NHW and the rest were mixed or unknown ethnicity. All tissues were uniformly homogenized and analyzed by tandem mass tag mass spectrometry (TMT-MS). Results: As a Quality control (QC) measure, proteins with more than 50% missing values were removed and iterative principal component analysis was conducted to remove outliers within brain regions. After QC, 9,180 and 9,734 proteins remained in the DLPC and STG proteome, respectively, of which approximately 9,000 proteins were shared between regions. Protein levels of microtubule-associated protein tau (MAPT) and amyloid-precursor protein (APP) demonstrated AD-related elevations in DLPFC tissues with a strong association with CERAD and Braak across racial groups. APOE4 protein levels in brain were highly concordant with APOE genotype of the individuals. Discussion: This comprehensive region resolved large-scale proteomic dataset provides a resource for the understanding of ethnoracial-specific protein differences in AD brain.
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AIM: To investigate the influence of ethnicity in social anxiety disorder (SAD), and the relationship with symptom severity, depression and substance use or abuse, in health sciences' students . METHODS: This was a cross-sectional survey of 112 1(st), 2(nd) and 3(rd) year students from the Faculty of Medicine and Health Sciences at Stellenbosch University, Cape Town, South Africa. The self-reported Social Anxiety Spectrum questionnaire was used to assess for SAD. The Social Phobia Inventory (SPIN) was adapted to a version called the E-SPIN (Ethnic-SPIN) in order to evaluate the effects of ethnicity. Two sub-questions per stem question were included to assess whether SAD symptoms in social interactions were ethnicity dependent. Substance use was assessed with the Alcohol Use Disorders Identification Test and Drug Use Disorders Identification Test, and depression with the Centre for Epidemiological Studies Depression Scale. RESULTS: Of 112 students who completed the E-SPIN questionnaire, 54.4% (n = 61) met criteria for SAD, with significantly more females than males meeting criteria. Ethnicity had a significant effect on SAD symptomatology, but there was no effect of ethnicity on the rates of drug and alcohol abuse in students with and without SAD. Overall significantly more students with SAD met criteria for depression compared with students without the disorder. CONCLUSION: Among university students, SAD is prevalent regardless of whether interactions are with individuals of the same or different ethnic group. However, ethnicity may be an important determinant of social anxiety for some ethnic groups. SAD was significantly associated with major depression but not significantly associated with drug or alcohol abuse.
