Columbia University Medical Center Blood Based Biomarkers of Risk for Alzheimer’s Disease among Adults with Down syndrome Nicole Schupf. Ph.D. Columbia University Medical Center

Dementia Risk in Adults with Down Syndrome. Adults with Down syndrome are at high risk for early onset of Alzheimer’s Disease Virtually all adults with DS have neuropathological changes consistent with AD, including deposition of Aβ in diffuse and neuritic plaques, by 40 years of age Most will develop clinical dementia by their late 60s

Neuropathological changes: Neuritic Plaques Neuritic plaques are extracellular lesions composed of degenerating neuronal structures such as axons, dendrites and synaptic terminals which are mixed with amyloid fibrils or surround an amyloid core. The blue-black spot in the center of this silver stained cortical section is the amyloid core of this classical plaque.

Neuropathological changes: Neurofibrillary Tangles These are neurofibrillary tangles in a Tau immuno stained cortical section. Neurofibrillary tangles are composed of paired helical filament within neurons and their processes. Neurofibrillary tangles interfere with the normal action of neurons and their synapses

Increased Risk of Dementia in Adults with DS Attributed, in part, to triplication and overexpression of amyloid precursor protein (APP) on chromosome 21, leading to elevated levels of Aβ peptides. However: --There large individual differences in Aβ peptide levels; -- There is wide range of dementia onset age and a substantial proportion main their abilities even at older ages despite extensive neuropathology --- Our study sought to identify preclinical blood based biomarkers of risk to identify those most likely to develop dementia

Cumulative Incidence of Alzheimer's Disease in Adults with DS and the General Population Age

Blood Based Preclinical Biomarkers Identifying preclinical biomarkers of risk and determining which individuals with DS are at the highest risk: (a) can provide insights into AD pathogenesis in adults with DS, (b) are critical to the early identification of MCI and dementia risk, and (c) can guide the development of effective intervention. (d) While cerebrospinal fluid (CSF) and positron emission tomography (PET) scan biomarkers are accurate in detecting AD pathology, they are invasive and not cost-effective

Proteomic Profiles Prior work from Dr. O’Bryant’s lab has validated a profile of proteins for detecting MCI and AD in the general population, across cohorts, assay technologies, species and tissue. Here we examined the utility of our previous profile for predicting the development of MCI and AD among a cohort of adults with DS

Classification of clinical status Dementia classification was made based upon consensus case conferences relying on evidence of stability or decline in cognitive and functional performance profiles over time Individuals were classified as: No Dementia: No cognitive or functional decline Mild Cognitive impairment: indications of cognitive and/or functional declines are present but severity or breadth is insufficient to indicate presence of dementia Possible Dementia: some signs and symptoms of decline in cognitive and functional status were present, but evidence of progressive decline over an extended period of time is limited Definite Dementia: based upon substantial decline in cognitive and functional status over time

Aging and Dementia in Adults with DS cohort : Participant Characteristics: non-demented; n=273 Incident dementia; n=83 Incident MCI; n = 101 Mean age at blood draw 51.4 (sd=7.1, 31-78) Female n=266 Male n=133 Up to 10 years of follow-up

Proteomic risk scores for MCI and AD Proteomics were conducted on banked plasma samples via electrochemiluminescence from a previously generated algorithm. Support vector machine (SVM) analyses were utilized to create proteomic risk scores We identified high/low cut-points scores for incident MCI and incident AD. Cox proportional hazards modeling examined the relation of the proteomic cut- scores to onset of MCI and AD, adjusting for age, sex, level of function, race/ethnicity and the APOE E4 allele.

Baseline characteristics for Incident MCI Nondemented Incident MCI Age (Mean, S.D)* 48.4 (6.6) 52.8 (6.1) Sex (n, % female)* 138 (76.2) 48 (47.5) Level of function (n, % severe /profound)* 56 (30.9) 46 (45.5) Ethnicity (n, % Non-Hispanic White) 167 (92.3) 90 (8.1) Any APOE E4 allele (n,%) 31 (17.5) 23 (22.8) Risk Score Predicted MCI (n,%)* 21 (12.2) 80 (80.2) * P < .05

Cumulative Incidence of MCI High Low HR = 7.09* *Adjusted for age at blood draw, sex, level of intellectual disability and APOE E4

Baseline for incident AD Baseline characteristics for incident AD Baseline for incident AD Characteristic Nondemented Incident Dementia Age (M + S.D.)* 49.8 (6.6) 54.2 (5.6) Sex (n, %female)* 190 (69.6) 48 (57.8) Level of function (n, % severe /profound) 107 (39.2) 37 (44.6) Ethnicity (n, % Non-Hispanic white) 248 (90.8) 77 (92.8) Any APOE E4 (n,%) 54 (20.1) 21 (25.3) Risk Score Predicted AD* 27 (9.9) 65 (78.3) * P < .05

Cumulative Incidence of AD by risk score with time since blood draw as the time to event variable. High Low HR=11.29* *Adjusted for age at blood draw, sex, level of intellectual disability and APOE E4

Comparison of general population profile with profile of MCI and AD in adults with DS Plasma AD Profile in non-Hispanic Whites Plasma Profile of Incident MCI in Down Syndrome – 8 of top 10 markers overlap Plasma Profile of Incident AD in Down Syndrome – 7 of top 10 markers overlap

Predictors The top 10 proteins associated with increased risk of MCI included IL6,CRP, l309, slCAM1, IL10, SAA, TPO, PPY, TenacinC, TARC The top 10 markers associated with increased risk of AD included IL6,CRP, l309, slCAM1, IL10, SAA, TPO, PPY, TenacinC, TARC It is noteworthy that the profiles were heavily weighted towards inflammatory markers for both MCI-DS and AD

Summary and Conclusions These results support the possibility of blood based profiles having utility in predicting onset of MCI and AD among adults with DS Inflammatory processes have been linked to the pathogenesis of Alzheimer’s disease and neuropsychiatric symptoms . A number of pro- and anti-inflammatory markers have been related to neuropsychiatric symptoms and functional level in aging and Alzheimer’s disease including TNFα ,IL-1 IL-6 IL-7 IL-10 , IL-15 and IL-18 it is possible that the proinflammatory biomarker profile will identify a specific subset of adults with DS where anti-inflammatory interventions, as a part of multi-modal therapy, may be of particular use We are extending these analyses and relating them to imaging (MRI, PET), metabolomic and genetic biomarkers in our new study of Biomarkers of Alzheimer's disease in Adults with Down Syndrome (ADDS), which is part of the Alzheimer’s Biomarkers Consortium- Down Syndrome (ABC-DS) funded by the NIA and NICHD

Acknowledgements Co-investigators: , Fan Zhang, Joseph H. Lee, Sharon J. Krinsky- McHale, Deborah Pang, Warren B. Zigman, Wayne Silverman, James Hall and Sid O’Bryant Supported by grant IIRG-08-90655 from the Alzheimer's Association (Schupf, O’Bryant), by grants P01HD035897 (Silverman) from NICHD, R01AG014673 (Schupf) from NIA, and by NYS through its Office for People with Developmental Disabilities. We thank the study participants and participating agencies from the tri-state area that made these studies possible