CSF Apo-E Levels Associate with Cognitive Decline and MRI Changes

CSF Apo-E levels associate with cognitive decline and MRI changes

Jon B Toledo, Xiao Da, Mike Weiner, David Wolk, Sharon X. Xie, Steven E Arnold, Christos Davatzikos, Leslie M Shaw, John Q Trojanowski For the Alzheimer’s Disease Neuroimaging Initiative

Methods

ADNI description and goals

The primary goal of ADNI has been to test whether serial MRI [1,7], PET [2], other biological markers [5], and clinical and neuropsychological assessment [4] can be combined to measure the progression of MCI and early AD. Determination of sensitive and specific markers of very early AD progression is intended to aid researchers and clinicians to develop new treatments and monitor their effectiveness, as well as reduce the time and cost of clinical trials. The Principal Investigator of this initiative is Michael W. Weiner, MD, VA Medical Center and University of California – San Francisco. ADNI is the result of efforts of many co-investigators from a broad range of academic institutions and private corporations.

Recruitment inclusion and exclusion criteria for ADNI 1

Inclusion criteria were as follows: 1) Hachinski Ischemic Score ≤4; 2) Permitted medications stable for 4 weeks prior to screening; 3) Geriatric Depression Scale score < 6; 4) visual and auditory acuity adequate for neuropsychological testing; good general health with no diseases precluding enrollment; 5) 6 grades of education or work history equivalent; 6) Ability to speak English or Spanish fluently; 7) A study partner with 10 hours per week of contact either in person or on the telephone who could accompany the participant to the clinic visits.

Criteria for the different diagnostic groups are summarized in supplementary table 1. Groups were age matched. Cognitively normal (CN) subjects must have no significant cognitive impairment or impaired activities of daily living. Clinical diagnosed Alzheimer’s disease patients (cAD) must have had mild cAD and had to meet the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association criteria for probable AD [3], whereas mild cognitive impairment subjects (MCI) should not meet these criteria, have largely intact general cognition as well as functional performance, but meet defined criteria for MCI.

CSF Biomarker collection and analysis

CSF was collected into polypropylene tubes or syringes provided to each site, and then be transferred into polypropylene transfer tubes without any centrifugation step followed by freezing on dry ice within 1 hour after collection for subsequent shipment overnight to the ADNI Biomarker Core laboratory at the University of Pennsylvania Medical Center on dry ice. Aliquots (0.5 ml) were prepared from these samples after thawing (1 hour) at room temperature and gentle mixing. The aliquots were stored in bar code–labeled polypropylene vials at -80°C. Fresh, never before thawed 0.5 mL aliquots for each subject’s set of longitudinal time points were analyzed on the same 96 well plate in the same analytical run for this study in order to minimize run to run and reagent kit lot sources of variation. Within run coefficient of variation (%CV) for duplicate samples ranged from 2.5-5.9% for Aβ1-42, 2.2-6.3% for t-tau and 2.0-6.5% for p-tau181 and the inter-run %CV for CSF pool samples ranged from 5.1-14% for Aβ1-42, 2.7 -11.2% for t-tau and 3.3-11.5% for p-tau181. Further information on the procedures and standard operating procedures (SOP) can be found in previous publications [6,5] and online (

Supplementary table 1. ADNI 1 criteria for recruitment of CN, MCI and AD subjects.

CN / MCI / AD
Memory complaints / Absent / Present / Present
MMSE / 24-30 / 24-30 / 20-26
CDR / 0 / 0.51 / 0.5-1.0
Delayed recall Logical Memory II subscale of WMSR / 16 YoEd: ≥9
8–15 YoEd: ≥5
0-7 YoEd: ≥3 / 16 YoEd: ≤8
8–15 YoEd: ≤4
0-7 YoEd: ≤2 / 16 YoEd: ≤8
8–15 YoEd: ≤4
0-7 YoEd: ≤2

AD: Alzheimer’s disease; CDR: Clinical Dementia Rating; CN: Cognitively normal; MCI: Mild cognitive impairment; MMSE: Mini-Mental State Examination; YoEd : years of education. 1Mandatory requirement of the memory box score being 0.5 or greater.

Supplementary Table 2. Characteristics of the patients with plasma Apo-E measurements.

CN
(n=58) / MCI
(n=395) / AD
(n=112) / p-value
Age at baseline (years)* / 75.1 (5.8) / 74.7 (7.4) / 74.7 (7.7) / 0.93
Gender (% male) / 50% / 64.5% / 57.0% / 0.0070
Education (years)* / 15.7 (2.8) / 15.7 (3.0) / 15.1 (3.2) / 0.24
APOE ε4 presence (%) / 5 (8.6%) / 211 (53.4%) / 76 (67.9%) / <0.0001
ADAS* / 9.6(4.1) / 18.6 (6.3) / 28.5 (7.8) / <0.0001
Plasma APOE levels (µg/ml)† / 71.0 (59.3-86.8) / 49.0 (37.5-62.0) / 51.0 (39.5-69.3) / 0.065
Number of cases with CSF measurements (%) / 57 (98.3%) / 196 (49.6%) / 103 (91.1%)
Aβ1-42 (pg/ml)† / 230.0 (230.0-265.0) / 146.0 (125.0-197.5) / 136.0 (121.3-159.5) / <0.0001
T-tau (pg/ml)† / 59.0 (48.0-76.0) / 86.0 (65.0-121.0) / 110.5 (80.0-154.8) / <0.0001
P-tau181 (pg/ml)† / 19.0 (15.0-24.0) / 31.0 (21.0-45.0) / 36.0 (29.0-49.0) / <0.0001

* Mean (standard deviation); †Median (1st quartile-3rd quartile).

Supplementary table 3. Cholesterol lowering drugs. This table summarizes ADNI subjects on cholesterol lowering drugs as well as the association of CSF and plasma Apo-E levels with cholesterol lowering drugs in analyses adjusted for gender, diagnosis and CSF tau values.

CSF / Plasma
n / β / S.E. / t-value / p- value / n / β / S.E. / t-value / p-value
Statins All1 / 131 / -0.059 / 0.097 / -0.61 / 0.54 / 230 / -0.28 / 0.096 / -3.01 / 0.0028
Statins BBB permeable2 / 56 / -0.059 / 0.13 / -0.47 / 0.64 / - / - / - / - / -
Statins BBB permeable & disputed3 / 118 / -0.034 / 0.10 / -0.35 / 0.73 / - / - / - / - / -
Fibrates / 4 / 0.45 / 0.42 / 1.05 / 0.29 / 11 / 0.40 / 0.37 / 1.08 / 0.28
Niacin / 9 / 0.08 / 0.29 / 0.30 / 0.77 / 14 / 0.002 / 0.029 / 0.01 / 1.0
Ezetimibe / 5 / 0.66 / 0.38 / 1.73 / 0.084 / 12 / -0.19 / 0.35 / -0.54 / 0.59
Resins / 6 / 1.6 / 0.35 / 0.45 / 0.64 / 8 / -0.38 / 0.36 / -1.05 / 0.29

1Includes: Atorvastatin, cerivastatin (no patient had it prescribed), fluvastatin, lovastatin, pravastatin, rosuvastatin and simvastatin. 2Includes: Lovastatin and simvastatin. 3Includes: Atorvastatin, cerivastatin (no patient had it prescribed), lovastatin, simvastatin.

Supplementary table 4. Associations with clinical outcomes in analyses stratified by APOE ε4 genotype. All models were adjusted for age, gender, education and clinical diagnosis at baseline (if two or more diagnostic groups were included). Additional covariates included in the model are detailed in the table.

Outcome / APOE ε4 status / Statistical Model / CSF Apo-E / T-tau/Aβ1-42
MCI to AD conversion / Lack of ε4 / Cox proportional hazards model / HR=0.64
z=-2.2
p=0.030 / HR=2.12
z=3.6
p=0.00028
MCI to AD conversion / Presence of ε4 / Cox proportional hazards model / HR=0.80
z=-1.26
p=0.21 / HR =1.23
z=0.91
p=0.36
ADAS-Cog longitudinal changes / Lack of ε4 / Mixed effects models / β=-0.045 (0.015)
t797=-3.00
p=0.0028 / β=0.10 (0.018)
t797=5.59
p<0.0001
ADAS-Cog longitudinal changes / Presence of ε4 / Mixed effects models / β=-0.064 (0.035)
t531=-1.85
p=0.064 / β=0.11 (0.043)
t531=2.68
p=0.0075

β: standardized coefficient (standard error); HR: Hazard ratio.

Supplementary table 5. Association of CSF Apo-E levels and t-tau/Aβ1-42 ratio with longitudinal MRI volume changes in the subjects lacking the APOE ε4 allele (model adjusted for gender, clinical diagnosis and intracranial volume).

Areas / CSF Apo-E / T-tau/Aβ1-42
β / S.E. / t-value / p-value / β / S.E. / t-value / p-value
Inferior Parietal / 64.01 / 20.09 / 3.19 / 0.030 / -62.09 / 21.58 / -2.88 / 0.0076
Fusiform / 37.84 / 14.01 / 2.70 / 0.047 / -65.25 / 15.10 / -4.32 / 0.0002
Precuneus / 39.21 / 14.28 / 2.75 / 0.047 / -42.22 / 15.40 / -2.74 / 0.011
Inferior Temporal / 44.54 / 18.01 / 2.47 / 0.068 / -67.49 / 19.45 / -3.47 / 0.0019
Medial Orbitofrontal / 15.14 / 6.53 / 2.32 / 0.083 / -24.06 / 7.00 / -3.44 / 0.0019
Middle Frontal / 66.91 / 30.32 / 2.21 / 0.092 / -61.15 / 32.69 / -1.87 / 0.073
Inferior Frontal / 31.84 / 14.87 / 2.14 / 0.093 / -20.09 / 15.97 / -1.26 / 0.21
Superior Frontal / 60.43 / 30.37 / 1.99 / 0.12 / -78.12 / 32.76 / -2.38 / 0.025
Entorhinal / 8.01 / 4.13 / 1.94 / 0.12 / -15.07 / 4.43 / -3.40 / 0.0019
Middle Temporal / 28.43 / 16.69 / 1.70 / 0.16 / -74.06 / 18.00 / -4.11 / 0.0003
Superior Parietal / 30.92 / 18.15 / 1.70 / 0.16 / -57.57 / 19.45 / -2.96 / 0.0064
Superior Temporal / 21.83 / 14.91 / 1.46 / 0.20 / -54.43 / 16.05 / -3.39 / 0.0019
Posterior Cingulate / 8.57 / 5.74 / 1.49 / 0.20 / -19.62 / 6.19 / -3.17 / 0.0036
Cuneus / 6.60 / 4.33 / 1.52 / 0.20 / -11.21 / 4.62 / -2.42 / 0.024
Lateral Orbitofrontal / 14.08 / 10.47 / 1.34 / 0.24 / -18.98 / 11.27 / -1.68 / 0.10
Transverse Temporal / 3.01 / 2.35 / 1.28 / 0.25 / -3.48 / 2.51 / -1.39 / 0.17
Parahippocampal / 3.61 / 3.27 / 1.10 / 0.32 / -16.34 / 3.49 / -4.68 / 0.0001
Lingual / 7.29 / 7.40 / 0.98 / 0.36 / -16.60 / 7.91 / -2.10 / 0.045
Anterior Cingulate / 4.07 / 5.94 / 0.69 / 0.52 / -15.07 / 6.38 / -2.36 / 0.025
Temporal Pole / 0.10 / 3.30 / 0.03 / 0.97 / -14.05 / 3.53 / -3.98 / 0.0004

β: standardized coefficient; S.E.: Standard error.

P-values are adjusted for multiple comparisons.

Supplementary table 6. Association of CSF Apo-E levels and t-tau/Aβ1-42 ratio with longitudinal MRI volume changes in the subjects with the APOE ε4 allele (model adjusted for gender, clinical diagnosis and intracranial volume).

Areas / CSF Apo-E / T-tau/Aβ1-42
β / S.E. / t-value / p-value / β / S.E. / t-value / p-value
Inferior Frontal / 52.77 / 17.51 / 3.01 / 0.06 / -30.67 / 17.86 / -1.72 / 0.15
Fusiform / 44.74 / 18.94 / 2.36 / 0.19 / -71.96 / 18.99 / -3.79 / 0.0037
Middle Frontal / 66.84 / 36.00 / 1.86 / 0.39 / -76.24 / 36.75 / -2.07 / 0.11
Inferior Parietal / 46.54 / 26.38 / 1.76 / 0.39 / -50.97 / 26.60 / -1.92 / 0.12
Middle Temporal / 35.92 / 24.00 / 1.50 / 0.54 / -81.78 / 24.04 / -3.40 / 0.0076
Inferior Temporal / 28.67 / 21.91 / 1.31 / 0.57 / -60.31 / 21.94 / -2.75 / 0.032
Superior Frontal / 45.21 / 37.30 / 1.21 / 0.57 / -54.97 / 37.79 / -1.45 / 0.22
Superior Parietal / 29.79 / 23.27 / 1.28 / 0.57 / -26.98 / 23.70 / -1.14 / 0.28
Entorhinal / 5.26 / 6.33 / 0.83 / 0.60 / -19.99 / 6.35 / -3.14 / 0.012
Precuneus / 11.59 / 13.86 / 0.84 / 0.60 / -24.35 / 14.42 / -1.69 / 0.15
Lingual / 9.18 / 10.53 / 0.87 / 0.60 / -15.20 / 10.64 / -1.43 / 0.22
Transverse Temporal / 2.33 / 2.60 / 0.90 / 0.60 / -3.49 / 2.72 / -1.28 / 0.27
Posterior Cingulate / 5.03 / 6.28 / 0.80 / 0.60 / -7.87 / 6.33 / -1.24 / 0.27
Lateral Orbitofrontal / 13.00 / 11.76 / 1.11 / 0.60 / -14.03 / 11.93 / -1.18 / 0.28
Anterior Cingulate / 5.88 / 7.74 / 0.76 / 0.60 / -4.06 / 7.84 / -0.52 / 0.64
Superior Temporal / 7.76 / 19.18 / 0.40 / 0.72 / -50.34 / 19.24 / -2.62 / 0.037
Temporal Pole / -3.38 / 6.34 / -0.53 / 0.72 / -12.90 / 6.34 / -2.03 / 0.11
Medial Orbitofrontal / 3.53 / 8.61 / 0.41 / 0.72 / -18.33 / 8.72 / -2.10 / 0.11
Cuneus / -2.40 / 4.80 / -0.50 / 0.72 / 1.15 / 4.98 / 0.23 / 0.82
Parahippocampal / 0.15 / 4.20 / 0.04 / 0.97 / -8.07 / 4.25 / -1.90 / 0.12

β: standardized coefficient; S.E.: Standard error.

P-values are adjusted for multiple comparisons.

Supplementary Figure 1. MRI atrophy. Parahippocampal ROI atrophy by CSF Apo-E tertiles (a) and CSF t-tau/Aβ1-42 ratio tertiles (b). Fusiform ROI atrophy by CSF Apo-E tertiles (c) and CSF t-tau/Aβ1-42 ratio tertiles (d).

Supplementary Figure 2. CSF and plasma Apo-E values.

References

1. Jack CR, Jr., Bernstein MA, Fox NC, Thompson P, Alexander G, Harvey D, Borowski B, Britson PJ, J LW, Ward C, Dale AM, Felmlee JP, Gunter JL, Hill DL, Killiany R, Schuff N, Fox-Bosetti S, Lin C, Studholme C, DeCarli CS, Krueger G, Ward HA, Metzger GJ, Scott KT, Mallozzi R, Blezek D, Levy J, Debbins JP, Fleisher AS, Albert M, Green R, Bartzokis G, Glover G, Mugler J, Weiner MW (2008) The Alzheimer's Disease Neuroimaging Initiative (ADNI): MRI methods. J Magn Reson Imaging 27 (4):685-691. doi:10.1002/jmri.21049

2. Jagust WJ, Bandy D, Chen K, Foster NL, Landau SM, Mathis CA, Price JC, Reiman EM, Skovronsky D, Koeppe RA (2010) The Alzheimer's Disease Neuroimaging Initiative positron emission tomography core. Alzheimers Dement 6 (3):221-229. doi:10.1016/j.jalz.2010.03.003

3. McKhann G, Drachman D, Folstein M, Katzman R, Price D, Stadlan EM (1984) Clinical diagnosis of Alzheimer's disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's Disease. Neurology 34 (7):939-944

4. Petersen RC, Aisen PS, Beckett LA, Donohue MC, Gamst AC, Harvey DJ, Jack CR, Jr., Jagust WJ, Shaw LM, Toga AW, Trojanowski JQ, Weiner MW (2010) Alzheimer's Disease Neuroimaging Initiative (ADNI): clinical characterization. Neurology 74 (3):201-209. doi:10.1212/WNL.0b013e3181cb3e25

5. Shaw LM, Vanderstichele H, Knapik-Czajka M, Clark CM, Aisen PS, Petersen RC, Blennow K, Soares H, Simon A, Lewczuk P, Dean R, Siemers E, Potter W, Lee VM, Trojanowski JQ (2009) Cerebrospinal fluid biomarker signature in Alzheimer's disease neuroimaging initiative subjects. Ann Neurol 65 (4):403-413. doi:10.1002/ana.21610

6. Shaw LM, Vanderstichele H, Knapik-Czajka M, Figurski M, Coart E, Blennow K, Soares H, Simon AJ, Lewczuk P, Dean RA, Siemers E, Potter W, Lee VM, Trojanowski JQ (2011) Qualification of the analytical and clinical performance of CSF biomarker analyses in ADNI. Acta Neuropathol 121 (5):597-609. doi:10.1007/s00401-011-0808-0

7. Weiner MW, Veitch DP, Aisen PS, Beckett LA, Cairns NJ, Green RC, Harvey D, Jack CR, Jagust W, Liu E, Morris JC, Petersen RC, Saykin AJ, Schmidt ME, Shaw L, Siuciak JA, Soares H, Toga AW, Trojanowski JQ (2012) The Alzheimer's Disease Neuroimaging Initiative: a review of papers published since its inception. Alzheimers Dement 8 (1 Suppl):S1-68. doi:10.1016/j.jalz.2011.09.172