Neighborhood disadvantage reduces cognitive reserve independent of neuropathologic change

INTRODUCTION

Individuals in socioeconomically disadvantaged neighborhoods exhibit increased risk for impaired cognitive function. Whether this association relates to the major dementia-related neuropathologies is unknown.

METHODS

This cross-sectional study included 469 autopsy cases from 2011 to 2023. The relationships between neighborhood disadvantage measured by Area Deprivation Index (ADI) percentiles categorized into tertiles, cognition evaluated by the last Mini-Mental State Examination (MMSE) scores before death, and 10 dementia-associated proteinopathies and cerebrovascular disease were assessed using regression analyses.

RESULTS

Higher ADI was significantly associated with lower MMSE score. This was mitigated by increasing years of education. ADI was not associated with an increase in dementia-associated neuropathologic change. Moreover, the significant association between ADI and cognition remained even after controlling for changes in major dementia-associated proteinopathies or cerebrovascular disease.

DISCUSSION

Neighborhood disadvantage appears to be associated with decreased cognitive reserve. This association is modified by education but is independent of the major dementia-associated neuropathologies.

Racial Differences in Clinical Presentation in Individuals Diagnosed With Frontotemporal Dementia

Importance

Prior research suggests there are racial disparities in the presentation of dementia, but this has not been investigated in the context of frontotemporal dementia (FTD).

Objective

To explore racial disparities in dementia severity, functional impairment, and neuropsychiatric symptoms in individuals with a diagnosis of FTD.

Design, Setting, and Participants

This exploratory cross-sectional study of National Alzheimer's Coordinating Center (NACC) data collected between June 2005 to August 2021 evaluated Asian, Black, and White individuals with a diagnosis of FTD (behavioral variant FTD or primary progressive aphasia). Excluded were races with limited data, including American Indian or Alaska Native (n = 4), Native Hawaiian or other Pacific Islander (n = 3), other (n = 13), and unknown (n = 24), and participants with symptom duration more than 4 SDs above the mean.

Main Outcomes and Measures

Racial differences at initial NACC visit were examined on Clinical Dementia Rating Dementia Staging Instrument plus NACC Frontotemporal Lobar Degeneration Behavior & Language Domains (FTLD-CDR), Functional Assessment Scale, and Neuropsychiatric Inventory using regression models. Matching was also performed to address the imbalance between racial groups.

Results

The final sample comprised 2478 individuals, of which 59 (2.4%) were Asian, 63 (2.5%) were Black, and 2356 (95.1%) were White. The mean (SD) age at initial visit was 65.3 (9.4) years and symptom duration at initial visit was 67.5 (35.6) months. Asian and Black individuals were considerably underrepresented, comprising a small percent of the sample. Black individuals had a higher degree of dementia severity on FTLD-CDR (β = 0.64; SE = 0.24; P = .006) and FTLD-CDR sum of boxes (β = 1.21; SE = 0.57; P = .03) and greater functional impairment (β = 3.83; SE = 1.49; P = .01). There were no differences on FTLD-CDR and Functional Assessment Scale between Asian and White individuals. Black individuals were found to exhibit a higher frequency of delusions, agitation, and depression (delusions: odds ratio [OR], 2.18; 95% CI, 1.15-3.93; P = .01; agitation: OR, 1.73; 95% CI, 1.03-2.93; P = .04; depression: OR, 1.75; 95% CI, 1.05-2.92; P = .03). Asian individuals were found to exhibit a higher frequency of apathy (OR, 1.89; 95% CI, 1.09-3.78; P = .03), nighttime behaviors (OR, 1.72; 95% CI, 1.01-2.91; P = .04), and appetite/eating (OR, 1.99; 95% CI, 1.17-3.47; P = .01) compared to White individuals.

Conclusions and Relevance

This exploratory study suggests there are racial disparities in dementia severity, functional impairment, and neuropsychiatric symptoms. Future work must address racial disparities and their underlying determinants as well as the lack of representation of racially minoritized individuals in nationally representative dementia registries.

Epigenetic age and socioeconomic status contribute to racial disparities in cognitive and functional aging between Black and White older Americans

Epigenetic age, a biological aging marker measured by DNA methylation, is a potential mechanism by which social factors drive disparities in age-related health. Epigenetic age gap is the residual between epigenetic age measures and chronological age. Previous studies showed associations between epigenetic age gap and age-related outcomes including cognitive capacity and performance on some functional measures, but whether epigenetic age gap contributes to disparities in these outcomes is unknown. We use data from the Health and Retirement Study to examine the role of epigenetic age gap in racial disparities in cognitive and functional outcomes and consider the role of socioeconomic status (SES). Epigenetic age measures are GrimAge or Dunedin Pace of Aging methylation (DPoAm). Cognitive outcomes are cross-sectional score and two-year change in Telephone Interview for Cognitive Status (TICS). Functional outcomes are prevalence and incidence of limitations performing Instrumental Activities of Daily Living (IADLs). We find, relative to White participants, Black participants have lower scores and greater decline in TICS, higher prevalence and incidence rates of IADL limitations, and higher epigenetic age gap. Age- and gender-adjusted analyses reveal that higher GrimAge and DPoAm gap are both associated with worse cognitive and functional outcomes and mediate 6-11% of racial disparities in cognitive outcomes and 19-39% of disparities in functional outcomes. Adjusting for SES attenuates most DPoAm associations and most mediation effects. These results support that epigenetic age gap contributes to racial disparities in cognition and functioning and may be an important mechanism linking social factors to disparities in health outcomes.

Contributions of neighborhood social environment and air pollution exposure to Black-White disparities in epigenetic aging

Racial disparities in many aging-related health outcomes are persistent and pervasive among older Americans, reflecting accelerated biological aging for Black Americans compared to White, known as weathering. Environmental determinants that contribute to weathering are poorly understood. Having a higher biological age, measured by DNA methylation (DNAm), than chronological age is robustly associated with worse age-related outcomes and higher social adversity. We hypothesize that individual socioeconomic status (SES), neighborhood social environment, and air pollution exposures contribute to racial disparities in DNAm aging according to GrimAge and Dunedin Pace of Aging methylation (DPoAm). We perform retrospective cross-sectional analyses among 2,960 non-Hispanic participants (82% White, 18% Black) in the Health and Retirement Study whose 2016 DNAm age is linked to survey responses and geographic data. DNAm aging is defined as the residual after regressing DNAm age on chronological age. We observe Black individuals have significantly accelerated DNAm aging on average compared to White individuals according to GrimAge (239%) and DPoAm (238%). We implement multivariable linear regression models and threefold decomposition to identify exposures that contribute to this disparity. Exposure measures include individual-level SES, census-tract-level socioeconomic deprivation and air pollution (fine particulate matter, nitrogen dioxide, and ozone), and perceived neighborhood social and physical disorder. Race and gender are included as covariates. Regression and decomposition results show that individual-level SES is strongly associated with and accounts for a large portion of the disparity in both GrimAge and DPoAm aging. Higher neighborhood deprivation for Black participants significantly contributes to the disparity in GrimAge aging. Black participants are more vulnerable to fine particulate matter exposure for DPoAm, perhaps due to individual- and neighborhood-level SES, which may contribute to the disparity in DPoAm aging. DNAm aging may play a role in the environment "getting under the skin", contributing to age-related health disparities between older Black and White Americans.

SOCIAL EPIGENETICS OF RACIAL DISPARITIES IN AGING

Racial disparities in many aging-related health outcomes are persistent and pervasive among older Americans. There are well-documented inequities in social and physical environmental exposures which may contribute to these disparities, but we lack understanding of the biological intermediates by which environmental exposures affect disparate health outcomes. DNA methylation (DNAm) aging captures the residual between biological age, robustly measured by GrimAge and Dunedin Pace of Aging methylation (DPoAm), and chronological age. We hypothesize that neighborhood social environment and air pollution exposures contribute to racial disparities in DNAm aging. We performed retrospective cross-sectional analyses among non-Hispanic participants (N=2611 White, N=639 Black) in the Health and Retirement Study whose 2016 DNAm age is linked to survey responses and geographic data. We observed Black individuals have significantly accelerated DNAm aging on average compared to White individuals according to GrimAge (599%) and DPoAm (498%). We implemented linear regression models and Kittagawa-Blinder-Oaxaca decomposition to identify exposures that contribute to this disparity. Exposure measures include census-tract-level Social Deprivation Index, perceived social stress, particulate matter (PM2.5), nitrogen dioxide, and ozone. Individual-level determinants include socioeconomic status, healthcare access, health status, and health behaviors. Results suggest these individual-level factors account for ~43% of the disparity in GrimAge and ~34% in DPoAm. Higher neighborhood socioeconomic deprivation for Black participants significantly contributes to the disparity in GrimAge, while greater vulnerability to PM2.5 contributes to the disparity in DPoAm. DNAm aging may play a role in the environment “getting under the skin” and contributing to age-related health disparities between Black and White Americans.

Abstract 521: Dual-targeting of IGF-1R and ErbB3 pathways in Ewing’s Sarcoma cellular models with istiratumab (MM-141), a bispecific, tetravalent monoclonal antibody

Ewing’s sarcoma family tumors (ES) are aggressive tumors that often present as metastatic in bone and soft tissue and predominantly affect adolescents and younger adults. Current treatment for ES includes surgical resection followed by loco-regional radiotherapy and chemotherapy. Survival rates for patients with metastatic disease continue to offer a particularly difficult clinical challenge, with a five-year survival rate of 20-30% for these patients. ES is primarily a genetic disease caused by fusion between the 5’ segment of the Ewing sarcoma breakpoint region 1 gene (EWSR1) on chromosome 22 and the 3’ portion of Friend leukemia virus integration site 1 (FLI1) on chromosome 11. Fusions of EWSR1 and other ETS transcription factors result in dis-regulated transcription factors which promote malignant progression of ES tumors. Recent studies have shown that most ES cell lines and clinical samples express IGF-1R. Importantly, an activated IGF-1R pathway appears to be a prerequisite for malignant transformation by the EWS-FLI1 translocation, presumably via activation of the PI3K-AKT and MAPK pathways. These findings have led to the preclinical and clinical evaluation of multiple IGF-1R-targeted therapeutics with varying results. Clinical experience with anti-IGF1R targeting therapies has demonstrated striking anticancer activity in minor subsets of patients with ES. Importantly, the paucity of a clinically useful biomarker to select patients continues to hinder IGF-1R drug development in ES. Istiratumab is an investigational, bi-specific, monoclonal antibody that acts as a tetravalent inhibitor of PI3K/AKT/mTOR, a major pro-survival pathway tumor cells use as a resistance mechanism to anticancer therapies. Istiratumab is designed to interfere with this pathway by blocking ligand-induced signaling through the IGF-1R and ErbB3 receptors, based on findings that ErbB3 activation mediates resistance to the IGF-1R blockade. We will present data in multiple ES models demonstrating the importance of both IGF-1R and ErbB3 in this disease as a mechanism of growth and resistance. Furthermore, preclinical xenograft studies demonstrate that the combination of istiratumab with an irinotecan-based chemotherapy regimen offers significant benefit over chemotherapy alone. These studies suggest that clinical evaluation of istiratumab in ES is warranted.

Citation Format: Isabel Yannatos, Adam Camblin, Zhenhua Li, Michael Curley, Gege Tan, Chrystal U. Louis, Vasileios Askoxylakis, Greg Finn, Birgit Schoeberl, Rachel Nering. Dual-targeting of IGF-1R and ErbB3 pathways in Ewing’s Sarcoma cellular models with istiratumab (MM-141), a bispecific, tetravalent monoclonal antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 521. doi:10.1158/1538-7445.AM2017-521

Abstract 1209: Istiratumab (MM-141), a bispecific antibody targeting IGF-1R and ErbB3, inhibits pro-survival signaling in vitro and potentiates the activity of standard of care chemotherapy in vivo in ovarian cancer models

Insulin-like growth factor receptor 1 (IGF-1R) signaling has been implicated in the pathogenesis of ovarian cancer. However, clinical trials evaluating monospecific IGF-1R inhibitors have demonstrated limited clinical efficacy. Our data indicate that ErbB3, a member of the ErbB receptor tyrosine kinase family, can activate pro-survival AKT signaling in response to IGF-1R blockade and may represent a potential escape route in the development of resistance to therapy. Istiratumab (MM-141), an IGF-1R and ErbB3 directed bispecific antibody, inhibits ligand activation of these signaling pathways and degrades IGF-1R and ErbB3 receptor-containing complexes, leading to inhibition of downstream pro-survival signaling. Here we tested the activity of istiratumab, alone and in combination with chemotherapy, in in vitro and in vivo models of ovarian cancer.

Anti-proliferative activity of istiratumab monotherapy was evaluated in a panel of ovarian cancer cell lines in vitro. The effects of istiratumab and the ligands IGF-1 and heregulin on IGF-1R- and ErbB3-mediated survival signaling were tested by ELISA and immunoblotting. Co-treatment assays with istiratumab and chemotherapy investigated mechanisms of synergy and additivity. Anti-tumor activity of istiratumab, alone and in combination with chemotherapy, was tested in in vivo ovarian xenograft tumor models.

Our results indicated that istiratumab monotherapy inhibits ovarian cancer cell line proliferation in vitro. In addition, istiratumab blocked ligand-mediated resistance to chemotherapy. Co-treatment of istiratumab, ligands or chemotherapy indicated a strong correlation between drug activity and IGF-1R expression. Furthermore, co-treatment of chemotherapies and ligands potentiated AKT activation, which was inhibited by istiratumab. In vivo studies showed that istiratumab potentiates the activity of chemotherapy in ovarian xenograft tumor models.

Our findings demonstrate that co-inhibition of IGF-1R and ErbB3 signaling with istiratumab can potentiate standard of care chemotherapies in ovarian tumor models and warrant further investigation of istiratumab as a potential therapy for ovarian cancer patients.

Citation Format: Michael D. Curley, Gege Tan, Isabel Yannatos, Adam Camblin, Sergio Iadevaia, Chrystal Louis, Alexey Lugovskoy. Istiratumab (MM-141), a bispecific antibody targeting IGF-1R and ErbB3, inhibits pro-survival signaling in vitro and potentiates the activity of standard of care chemotherapy in vivo in ovarian cancer models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1209.