1
|
Royall DR, Palmer RF. INFLAMMATION's cognitive impact revealed by a novel "Line of Identity" approach. PLoS One 2024; 19:e0295386. [PMID: 38517924 PMCID: PMC10959355 DOI: 10.1371/journal.pone.0295386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 11/22/2023] [Indexed: 03/24/2024] Open
Abstract
IMPORTANCE Dementia is an "overdetermined" syndrome. Few individuals are demented by any single biomarker, while several may independently explain small fractions of dementia severity. It may be advantageous to identify individuals afflicted by a specific biomarker to guide individualized treatment. OBJECTIVE We aim to validate a psychometric classifier to identify persons adversely impacted by inflammation and replicate it in a second cohort. DESIGN Secondary analyses of data collected by the Texas Alzheimer's Research and Care Consortium (TARCC) (N = 3497) and the Alzheimer's Disease Neuroimaging Initiative (ADNI) (N = 1737). SETTING Two large, well-characterized multi-center convenience samples. PARTICIPANTS Volunteers with normal cognition (NC), Mild Cognitive Impairment (MCI) or clinical "Alzheimer's Disease (AD)". EXPOSURE Participants were assigned to "Afflicted" or "Resilient" classes on the basis of a psychometric classifier derived by confirmatory factor analysis. MAIN OUTCOME(S) AND MEASURE(S) The groups were contrasted on multiple assessments and biomarkers. The groups were also contrasted regarding 4-year prospective conversions to "AD" from non-demented baseline diagnoses (controls and MCI). The Afflicted groups were predicted to have adverse levels of inflammation-related blood-based biomarkers, greater dementia severity and greater risk of prospective conversion. RESULTS In ADNI /plasma, 47.1% of subjects were assigned to the Afflicted class. 44.6% of TARCC's subjects were afflicted, 49.5% of non-Hispanic Whites (NHW) and 37.2% of Mexican Americans (MA). There was greater dementia severity in the Afflicted class [by ANOVA: ADNI /F(1) = 686.99, p <0.001; TARCC /F(1) = 1544.01, p <0.001]. "INFLAMMATION" factor composite scores were significantly higher (adverse) in Afflicted subjects [by ANOVA in ADNI /plasma F(1) = 1642.64, p <0.001 and in TARCC /serum F(1) = 3059.96, p <0.001]. Afflicted cases were more likely to convert to AD in the next four years [by Cox's F, ADNI /plasma: F (252, 268) = 3.74 p < 0.001; TARCC /serum: F (160, 134) = 3.03, p < 0.001 (in TARCC's entire sample), F (110, 90) = 4.92, p <0.001 in NHW, and F(50, 44) = 2.13, p = 0.006 in MA]. The proportions converting were similar among afflicted NHW in both cohorts /biofluids but MA exhibited a lower risk (7% in TARCC /serum at 48 months). CONCLUSIONS AND RELEVANCE Our inflammation-specific psychometric classifier selects individuals with pre-specified biomarker profiles and predicts conversion to "AD" across cohorts, biofluids, and ethnicities. This algorithm might be applied to any dementia-related biomarker making the psychometric estimation of individual biomarker effects feasible without biomarker assessment. Our approach also distinguishes individuals resilient to individual biomarker effects allowing for more accurate prediction and precision intervention.
Collapse
Affiliation(s)
- Donald R. Royall
- Department of Psychiatry and Behavioral Science, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- The Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Disease, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| |
Collapse
|
2
|
Royall DR, Palmer RF. Statin use moderates APOE's and CRP's associations with dementia and is associated with lesser dementia severity in ε4 carriers. Alzheimers Dement 2024; 20:1627-1636. [PMID: 38055626 PMCID: PMC10984456 DOI: 10.1002/alz.13543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/21/2023] [Accepted: 10/01/2023] [Indexed: 12/08/2023]
Abstract
INTRODUCTION We tested the effect of statins on C-reactive protein (CRP) and apolipoprotein E (APOE)'s associations with dementia severity. METHODS A total of 1725 participants of the Alzheimer's Disease Neuroimaging Initiative (ADNI) were assigned from 12-month follow-up data into the following groups: (1) ε4 (-)/statin (-), (2) ε4 (-)/statin (+), (3) ε4 (+)/statin (-), and (4) ε4 (+)/statin (+). Dementia severity was assessed by a δ homolog: "dHABS." A mediation model was stratified on statin use and moderation effects tested by a chi-square difference. RESULTS Plasma CRP level decreased with ε4 allelic dose. Statins had no effect on the dHABS d-score in non-carriers but were associated with better scores in carriers. Treated carriers did not have more severe dementia than non-carriers. Statin use moderated the mutual adjusted effects of APOE and CRP. CRP was not a mediator of APOE's effect. DISCUSSION Statins may provide a protective effect on the dementia severity of ε4 carriers. HIGHLIGHTS δ is a dementia-specific phenotype related to general intelligence "g" and is assessed via a "d-score." Apolipoprotein E (APOE) and plasma C-reactive protein (CRP) are independently associated with δ. Plasma CRP decreases with ε4 allelic dose. Statins were associated with better (less demented) d-scores in ε4 carriers but had no effect in non-ε4 carriers. Treated ε4 carriers did not have more severe dementia than non-carriers. Statin use moderated the effects of APOE and CRP on δ. CRP was not a mediator of APOE's effect on δ.
Collapse
Affiliation(s)
- Donald R. Royall
- Department of PsychiatryUniversity of Texas Health Science CenterSan AntonioTexasUSA
- Department of MedicineUniversity of Texas Health Science CenterSan AntonioTexasUSA
- Department of Family and Community MedicineUniversity of Texas Health Science CenterSan AntonioTexasUSA
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative DisordersSan AntonioUSA
| | - Raymond F. Palmer
- Department of Family and Community MedicineUniversity of Texas Health Science CenterSan AntonioTexasUSA
| | | |
Collapse
|
3
|
Tao Q, Zhang C, Mercier G, Lunetta K, Ang TFA, Akhter‐Khan S, Zhang Z, Taylor A, Killiany RJ, Alosco M, Mez J, Au R, Zhang X, Farrer LA, Qiu WWQ. Identification of an APOE ε4-specific blood-based molecular pathway for Alzheimer's disease risk. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2023; 15:e12490. [PMID: 37854772 PMCID: PMC10579631 DOI: 10.1002/dad2.12490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 09/25/2023] [Indexed: 10/20/2023]
Abstract
INTRODUCTION The precise apolipoprotein E (APOE) ε4-specific molecular pathway(s) for Alzheimer's disease (AD) risk are unclear. METHODS Plasma protein modules/cascades were analyzed using weighted gene co-expression network analysis (WGCNA) in the Alzheimer's Disease Neuroimaging Initiative study. Multivariable regression analyses were used to examine the associations among protein modules, AD diagnoses, cerebrospinal fluid (CSF) phosphorylated tau (p-tau), and brain glucose metabolism, stratified by APOE genotype. RESULTS The Green Module was associated with AD diagnosis in APOE ε4 homozygotes. Three proteins from this module, C-reactive protein (CRP), complement C3, and complement factor H (CFH), had dose-dependent associations with CSF p-tau and cognitive impairment only in APOE ε4 homozygotes. The link among these three proteins and glucose hypometabolism was observed in brain regions of the default mode network (DMN) in APOE ε4 homozygotes. A Framingham Heart Study validation study supported the findings for AD. DISCUSSION The study identifies the APOE ε4-specific CRP-C3-CFH inflammation pathway for AD, suggesting potential drug targets for the disease.Highlights: Identification of an APOE ε4 specific molecular pathway involving blood CRP, C3, and CFH for the risk of AD.CRP, C3, and CFH had dose-dependent associations with CSF p-Tau and brain glucose hypometabolism as well as with cognitive impairment only in APOE ε4 homozygotes.Targeting CRP, C3, and CFH may be protective and therapeutic for AD onset in APOE ε4 carriers.
Collapse
Affiliation(s)
- Qiushan Tao
- Department of Pharmacology, Physiology & BiophysicsBoston University School of MedicineBostonMassachusettsUSA
- Slone Epidemiology CenterSchool of Public HealthBoston University Medical Campus (BUMC)BostonMassachusettsUSA
| | - Chao Zhang
- Section of Computational BiomedicineDepartment of MedicineBoston University School of MedicineBostonMassachusettsUSA
| | - Gustavo Mercier
- Section of Molecular Imaging and Nuclear MedicineDepartment of RadiologyBoston University School of MedicineBostonMassachusettsUSA
| | - Kathryn Lunetta
- Slone Epidemiology CenterSchool of Public HealthBoston University Medical Campus (BUMC)BostonMassachusettsUSA
- Department of BiostatisticsBoston University School of Public HealthBostonMassachusettsUSA
| | - Ting Fang Alvin Ang
- Slone Epidemiology CenterSchool of Public HealthBoston University Medical Campus (BUMC)BostonMassachusettsUSA
- Department of Anatomy & NeurobiologyBoston University School of MedicineBostonMassachusettsUSA
| | - Samia Akhter‐Khan
- Department of Health Service & Population ResearchKing's College London, LondonDavid Goldberg CentreLondonUK
| | - Zhengrong Zhang
- Department of Pharmacology, Physiology & BiophysicsBoston University School of MedicineBostonMassachusettsUSA
| | - Andrew Taylor
- Department of OphthalmologyBoston University School of MedicineBostonMassachusettsUSA
| | - Ronald J. Killiany
- Department of Anatomy & NeurobiologyBoston University School of MedicineBostonMassachusettsUSA
| | - Michael Alosco
- Department of NeurologyBoston University School of MedicineBostonMassachusettsUSA
| | - Jesse Mez
- Department of NeurologyBoston University School of MedicineBostonMassachusettsUSA
- Alzheimer's Disease and CTE CentersBoston University School of MedicineBostonMassachusettsUSA
| | - Rhoda Au
- Slone Epidemiology CenterSchool of Public HealthBoston University Medical Campus (BUMC)BostonMassachusettsUSA
- Department of Anatomy & NeurobiologyBoston University School of MedicineBostonMassachusettsUSA
| | - Xiaoling Zhang
- Department of MedicineBoston University School of MedicineBostonMassachusettsUSA
| | - Lindsay A. Farrer
- Alzheimer's Disease and CTE CentersBoston University School of MedicineBostonMassachusettsUSA
- Department of MedicineBoston University School of MedicineBostonMassachusettsUSA
| | - Wendy Wei Qiao Qiu
- Department of Pharmacology, Physiology & BiophysicsBoston University School of MedicineBostonMassachusettsUSA
- Alzheimer's Disease and CTE CentersBoston University School of MedicineBostonMassachusettsUSA
- Department of PsychiatryBoston University School of MedicineBostonMassachusettsUSA
| | | |
Collapse
|
4
|
Royall DR, Palmer RF. Multiple Adipokines Predict Dementia Severity as Measured by δ: Replication Across Biofluids and Cohorts. J Alzheimers Dis 2023; 92:639-652. [PMID: 36776066 DOI: 10.3233/jad-221052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND We have explored dementia's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium (TARCC) study. Among them are adipokines, i.e., proteins secreted by adipose tissue some of which have been associated with cognitive impairment. OBJECTIVE To associate adipokines with dementia severity and replicate their association across cohorts and biofluids (serum /plasma). METHODS We used eight rationally chosen blood-based protein biomarkers as indicators of a latent variable, i.e., "Adipokines". We then associated that construct with dementia severity as measured by the latent dementia-specific phenotype "δ" in structural equation models (SEM). Significant factor loadings and Adipokines' association with δ were replicated across biofluids in the Alzheimer's Disease Neuroimaging Initiative (ADNI). RESULTS Eight adipokine proteins loaded significantly on the Adipokines construct. Adipokines measured in plasma (ADNI) or serum (TARCC) explained 24 and 70% of δ's variance, respectively. An Adipokine composite score, derived from the latent variables, rose significantly across clinical diagnoses and achieved high areas under the receiver operating characteristic curve (ROC/AUC) for discrimination of Alzheimer's disease from normal controls (NC) or cases of mild cognitive impairment (MCI) and between NC and MCI. CONCLUSION These results again suggest that SEM can be used to create latent biomarker classifiers that replicate across samples and biofluids, and that a substantial fraction of dementia's variance is attributable to peripheral blood-based protein levels via the patterns codified in those latent constructs.
Collapse
Affiliation(s)
- Donald R Royall
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, TX, USA.,Department of Medicine, the University of Texas Health Science Center, San Antonio, TX, USA.,Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA.,The Glenn Biggs Institute for Alzheimer's and Neurodegenerative Disease, the University of Texas Health ScienceCenter, San Antonio, TX, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
| |
Collapse
|
5
|
Huang J, Tao Q, Ang TFA, Farrell J, Zhu C, Wang Y, Stein TD, Lunetta KL, Massaro J, Mez J, Au R, Farrer LA, Qiu WQ, Zhang X. The impact of increasing levels of blood C-reactive protein on the inflammatory loci SPI1 and CD33 in Alzheimer's disease. Transl Psychiatry 2022; 12:523. [PMID: 36550123 PMCID: PMC9780312 DOI: 10.1038/s41398-022-02281-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/19/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Apolipoprotein ε4 (APOE ε4) is the most significant genetic risk factor for late-onset Alzheimer's disease (AD). Elevated blood C-reactive protein (CRP) further increases the risk of AD for people carrying the APOE ε4 allele. We hypothesized that CRP, as a key inflammatory element, could modulate the impact of other genetic variants on AD risk. We selected ten single nucleotide polymorphisms (SNPs) in reported AD risk loci encoding proteins related to inflammation. We then tested the interaction effects between these SNPs and blood CRP levels on AD incidence using the Cox proportional hazards model in UK Biobank (n = 279,176 white participants with 803 incident AD cases). The five top SNPs were tested for their interaction with different CRP cutoffs for AD incidence in the Framingham Heart Study (FHS) Generation 2 cohort (n = 3009, incident AD = 156). We found that for higher concentrations of serum CRP, the AD risk increased for SNP genotypes in 3 AD-associated genes (SPI1, CD33, and CLU). Using the Cox model in stratified genotype analysis, the hazard ratios (HRs) for the association between a higher CRP level (≥10 vs. <10 mg/L) and the risk of incident AD were 1.94 (95% CI: 1.33-2.84, p < 0.001) for the SPI1 rs1057233-AA genotype, 1.75 (95% CI: 1.20-2.55, p = 0.004) for the CD33 rs3865444-CC genotype, and 1.76 (95% CI: 1.25-2.48, p = 0.001) for the CLU rs9331896-C genotype. In contrast, these associations were not observed in the other genotypes of these genes. Finally, two SNPs were validated in 321 Alzheimer's Disease Neuroimaging (ADNI) Mild Cognitive Impairment (MCI) patients. We observed that the SPI1 and CD33 genotype effects were enhanced by elevated CRP levels for the risk of MCI to AD conversion. Furthermore, the SPI1 genotype was associated with CSF AD biomarkers, including t-Tau and p-Tau, in the ADNI cohort when the blood CRP level was increased (p < 0.01). Our findings suggest that elevated blood CRP, as a peripheral inflammatory biomarker, is an important moderator of the genetic effects of SPI1 and CD33 in addition to APOE ε4 on AD risk. Monitoring peripheral CRP levels may be helpful for precise intervention and prevention of AD for these genotype carriers.
Collapse
Affiliation(s)
- Jinghan Huang
- Departments of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, MA, USA
| | - Qiushan Tao
- Departments of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Ting Fang Alvin Ang
- Departments of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, USA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
| | - John Farrell
- Departments of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, MA, USA
| | - Congcong Zhu
- Departments of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, MA, USA
| | - Yixuan Wang
- Departments of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, MA, USA
| | - Thor D Stein
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
- Alzheimer's Disease Research Center, Boston University School of Medicine, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA, USA
- VA Bedford Healthcare System, Bedford, MA, USA
| | - Kathryn L Lunetta
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
- Framingham Heart Study, Boston University School of Medicine, Framingham, MA, USA
| | - Joseph Massaro
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
- Framingham Heart Study, Boston University School of Medicine, Framingham, MA, USA
| | - Jesse Mez
- Alzheimer's Disease Research Center, Boston University School of Medicine, Boston, MA, USA
- Framingham Heart Study, Boston University School of Medicine, Framingham, MA, USA
- Departments of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Rhoda Au
- Departments of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, USA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
- Alzheimer's Disease Research Center, Boston University School of Medicine, Boston, MA, USA
- Framingham Heart Study, Boston University School of Medicine, Framingham, MA, USA
- Departments of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Lindsay A Farrer
- Departments of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, MA, USA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
- Alzheimer's Disease Research Center, Boston University School of Medicine, Boston, MA, USA
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
- Framingham Heart Study, Boston University School of Medicine, Framingham, MA, USA
- Departments of Neurology, Boston University School of Medicine, Boston, MA, USA
- Departments of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Wei Qiao Qiu
- Departments of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA.
- Alzheimer's Disease Research Center, Boston University School of Medicine, Boston, MA, USA.
- Departments of Psychiatry, Boston University School of Medicine, Boston, MA, USA.
| | - Xiaoling Zhang
- Departments of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, MA, USA.
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.
| |
Collapse
|
6
|
Royall DR. Reader Response: Impact of C-Reactive Protein on Cognition and Alzheimer Disease Biomarkers in Homozygous APOE ɛ4 Carriers. Neurology 2022; 99:918-919. [PMID: 36376090 DOI: 10.1212/wnl.0000000000201508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023] Open
|
7
|
Qiu WQ, Tao Q, Akhter-Khan SC. Author Response: Impact of C-Reactive Protein on Cognition and Alzheimer Disease Biomarkers in Homozygous APOE ɛ4 Carriers. Neurology 2022; 99:919. [PMID: 36376087 DOI: 10.1212/wnl.0000000000201509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023] Open
|
8
|
Berger M, Cooter M, Roesler AS, Chung S, Park J, Modliszewski JL, VanDusen KW, Thompson JW, Moseley A, Devinney MJ, Smani S, Hall A, Cai V, Browndyke JN, Lutz MW, Corcoran DL. APOE4 Copy Number-Dependent Proteomic Changes in the Cerebrospinal Fluid. J Alzheimers Dis 2020; 79:511-530. [PMID: 33337362 PMCID: PMC7902966 DOI: 10.3233/jad-200747] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Background: APOE4 has been hypothesized to increase Alzheimer’s disease risk by increasing neuroinflammation, though the specific neuroinflammatory pathways involved are unclear. Objective: Characterize cerebrospinal fluid (CSF) proteomic changes related to APOE4 copy number. Methods: We analyzed targeted proteomic data from ADNI CSF samples using a linear regression model adjusting for age, sex, and APOE4 copy number, and additional linear models also adjusting for AD clinical status or for CSF Aβ, tau, or p-tau levels. False discovery rate was used to correct for multiple comparisons correction. Results: Increasing APOE4 copy number was associated with a significant decrease in a CRP peptide level across all five models (q < 0.05 for each), and with significant increases in ALDOA, CH3L1 (YKL-40), and FABPH peptide levels (q < 0.05 for each) except when controlling for AD clinical status or neurodegeneration biomarkers (i.e., CSF tau or p-tau). In all models except the one controlling for CSF Aβ levels, though not statistically significant, there was a consistent inverse direction of association between APOE4 copy number and the levels of all 24 peptides from all 8 different complement proteins measured. The odds of this happening by chance for 24 unrelated peptides would be less than 1 in 16 million. Conclusion: Increasing APOE4 copy number was associated with decreased CSF CRP levels across all models, and increased CSF ALDOA, CH3L1, and FABH levels when controlling for CSF Aβ levels. Increased APOE4 copy number may also be associated with decreased CSF complement pathway protein levels, a hypothesis for investigation in future studies.
Collapse
Affiliation(s)
- Miles Berger
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.,Center for Cognitive Neuroscience, Duke Institute for Brain Sciences, Durham, NC, USA.,Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, NC, USA
| | - Mary Cooter
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Alexander S Roesler
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Stacey Chung
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - John Park
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | | | - Keith W VanDusen
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - J Will Thompson
- Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Arthur Moseley
- Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Michael J Devinney
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Shayan Smani
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.,Trinity College of Arts and Sciences, Duke University, Durham, NC, USA
| | - Ashley Hall
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Victor Cai
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.,Trinity College of Arts and Sciences, Duke University, Durham, NC, USA
| | - Jeffrey N Browndyke
- Center for Cognitive Neuroscience, Duke Institute for Brain Sciences, Durham, NC, USA.,Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, NC, USA.,Department of Psychiatry & Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Michael W Lutz
- Department of Neurology, Duke University Medical Center, Durham, NC, USA
| | - David L Corcoran
- Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | | |
Collapse
|
9
|
Apolipoprotein E genotype and the association between C-reactive protein and postoperative delirium: Importance of gene-protein interactions. Alzheimers Dement 2020; 16:572-580. [PMID: 31761478 DOI: 10.1016/j.jalz.2019.09.080] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Apolipoprotein E (APOE) status may modify the risk of postoperative delirium conferred by inflammation. METHODS We tested whether APOE modifies the established association between C-reactive protein (CRP) and delirium incidence, severity, and duration in 553 noncardiac surgical patients aged 70 and older. High postoperative plasma CRP (≥234.12 mg/L) was defined by the highest sample-based quartile. Delirium was determined using the Confusion Assessment Method and chart review, and severity was determined by the Confusion Assessment Method-Severity score. RESULTS APOE ε4 carrier prevalence was 19%, and postoperative delirium occurred in 24%. The relationship between CRP and delirium incidence, severity, and duration differed by ε4 status. Among ε4 carriers, there was a strong relationship between high CRP (vs. low CRP) and delirium incidence (relative risk [95% confidence interval], 3.0 [1.4-6.7]); however, no significant association was observed among non-ε4 carriers (relative risk [95% CI], 1.2 [0.8-1.7]). DISCUSSION Our findings raise the possibility that APOE ε4 carrier status may modify the relationship between postoperative day 2 CRP levels and postoperative delirium.
Collapse
|
10
|
Royall DR, Bishnoi RJ, Palmer RF. Blood-based protein predictors of dementia severity as measured by δ: Replication across biofluids and cohorts. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2019; 11:763-774. [PMID: 31909176 PMCID: PMC6939046 DOI: 10.1016/j.dadm.2019.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Dementia severity can be empirically described by the latent dementia phenotype "δ" and its various composite "homologs". We have explored δ's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium (TARCC) study. However, it would be convenient to replicate those associations in the Alzheimer's Disease Neuroimaging Initiative (ADNI). To this end, we recently engineered a δ homolog from observed cognitive performance measures common to both projects (i.e., "dT2A"). METHODS We used nine rationally chosen peripheral blood-based protein biomarkers as indicators of a latent variable "INFLAMMATION". We then associated that construct with dT2A in structural equation models adjusted for age, gender, depressive symptoms, and apolipoprotein E (APOE) ε4 allelic burden. Significant factor loadings and INFLAMMATION's association with dT2A were confirmed in random splits of TARCC's relatively large sample, and across biofluids in the ADNI. RESULTS Nine proteins measured in serum (TARCC) or plasma (ADNI) explained ≅10% of dT2A's variance in both samples, independently of age, APOE, education, and gender. All loaded significantly on INFLAMMATION, and positively or negatively, depending on their known roles are PRO- or ANTI-inflammatory proteins, respectively. The parameters of interest were confirmed across random 50% splits of the TARCC's sample, and replicated across biofluids in the ADNI. DISCUSSION These results suggest that SEM can be used to replicate biomarker findings across samples and biofluids, and that a substantial fraction of dementia's variance is attributable to peripheral blood-based protein levels.
Collapse
Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA
- Department of Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
- Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
- The Biggs Institute for Alzheimer's and Neurodegenerative Disease, the University of Texas Health Science Center, San Antonio, TX, USA
| | - Ram J. Bishnoi
- The Department of Psychiatry, The Medical College of Georgia, Augusta, GA, USA
| | - Raymond F. Palmer
- Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
| |
Collapse
|
11
|
Royall DR, Palmer RF. Blood-based protein mediators of senility with replications across biofluids and cohorts. Brain Commun 2019; 2:fcz036. [PMID: 32954311 PMCID: PMC7425523 DOI: 10.1093/braincomms/fcz036] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/25/2019] [Accepted: 10/07/2019] [Indexed: 01/08/2023] Open
Abstract
Dementia severity can be quantitatively described by the latent dementia phenotype 'δ' and its various composite 'homologues'. We have explored δ's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium. However, it would be convenient to replicate them in the Alzheimer's Disease Neuroimaging Initiative. To that end, we have engineered a δ homologue from the observed cognitive performance measures common to both projects [i.e. 'd:Texas Alzheimer's Research and Care Consortium to Alzheimer's Disease Neuroimaging Initiative' (dT2A)]. In this analysis, we confirm 13/22 serum proteins as partial mediators of age's effect on dementia severity as measured by dT2A in the Texas Alzheimer's Research and Care Consortium and then replicate 4/13 in the Alzheimer's Disease Neuroimaging Initiative's plasma data. The replicated mediators of age-specific effects on dementia severity are adiponectin, follicle-stimulating hormone, pancreatic polypeptide and resistin. In their aggregate, the 13 confirmed age-specific mediators suggest that 'cognitive frailty' pays a role in dementia severity as measured by δ. We provide both discriminant and concordant support for that hypothesis. Weight, calculated low-density lipoprotein and body mass index are partial mediators of age's effect in the Texas Alzheimer's Research and Care Consortium. Biomarkers related to other disease processes (e.g. cerebrospinal fluid Alzheimer's disease-specific biomarkers in the Alzheimer's Disease Neuroimaging Initiative) are not. It now appears that dementia severity is the sum of multiple independent processes impacting δ. Each may have a unique set of mediating biomarkers. Age's unique effect appears to be at least partially mediated through proteins related to frailty. Age-specific mediation effects can be replicated across cohorts and biofluids. These proteins may offer targets for the remediation of age-specific cognitive decline (aka 'senility'), help distinguish it from other determinants of dementia severity and/or provide clues to the biology of Aging Proper.
Collapse
Affiliation(s)
- Donald R Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- Department of Medicine, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
- The Glenn Biggs Institute for Alzheimer’s & Neurodegenerative Diseases, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | | |
Collapse
|
12
|
Chernick D, Ortiz-Valle S, Jeong A, Qu W, Li L. Peripheral versus central nervous system APOE in Alzheimer's disease: Interplay across the blood-brain barrier. Neurosci Lett 2019; 708:134306. [PMID: 31181302 DOI: 10.1016/j.neulet.2019.134306] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 12/20/2022]
Abstract
The apolipoprotein E (APOE) ε4 allele has been demonstrated as the preeminent genetic risk factor for late onset Alzheimer's disease (AD), which comprises greater than 90% of all AD cases. The discovery of the connection between different APOE genotypes and AD risk in the early 1990s spurred three decades of intense and comprehensive research into the function of APOE in the normal and diseased brain. The importance of APOE in the periphery has been well established, due to its pivotal role in maintaining cholesterol homeostasis and cardiovascular health. The influence of vascular factors on brain function and AD risk has been extensively studied in recent years. As a major apolipoprotein regulating multiple molecular pathways beyond its canonical lipid-related functions in the periphery and the central nervous system, APOE represents a critical link between the two compartments, and may influence AD risk from both sides of the blood-brain barrier. This review discusses recent advances in understanding the different functions of APOE in the periphery and in the brain, and highlights several promising APOE-targeted therapeutic strategies for AD.
Collapse
Affiliation(s)
| | | | - Angela Jeong
- Department of Experimental and Clinical Pharmacology, Minneapolis, MN, United States
| | - Wenhui Qu
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Ling Li
- Departments of Pharmacology, Minneapolis, MN, United States; Department of Experimental and Clinical Pharmacology, Minneapolis, MN, United States; Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States.
| |
Collapse
|
13
|
Royall DR, Palmer RF. Selection for depression-specific dementia cases with replication in two cohorts. PLoS One 2019; 14:e0216413. [PMID: 31150419 PMCID: PMC6544211 DOI: 10.1371/journal.pone.0216413] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/21/2019] [Indexed: 01/01/2023] Open
Abstract
The latent variable "δ" (for "dementia") provides an etiologically "agnostic" omnibus dementia severity metric capable of recognizing the dementing potential of any condition. Depressive symptoms are independent predictors of δ and are thereby implicated as "dementing". Serum resistin levels partially mediate the association between depressive symptoms and δ. We use a novel "off-diagonal" CHI SQ algorithm to demonstrate our ability to select individuals demented solely by depression's effect in both the Texas Alzheimer's Research and Care Consortium (TARCC) (N ≌ 3,500), and the Alzheimer's Disease Neuroimaging Initiative (ADNI (N ≌ 1,750), and demonstrate the higher resistin levels of such cases in TARCC. This approach can be adapted to any δ-related dementia risk factor or biomarker and used identify individuals who might revert back to non-demented states after its successful treatment.
Collapse
Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- South Texas Veterans’ Health System Audie L. Murphy Division Geriatric Research Education and Clinical Care Center, San Antonio, Texas, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
| | | |
Collapse
|
14
|
Royall DR, Palmer RF. A δ Homolog for Dementia Case Finding with Replication in the Alzheimer's Disease Neuroimaging Initiative. J Alzheimers Dis 2019; 67:67-79. [PMID: 30507569 DOI: 10.3233/jad-171053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Dementia can be empirically described by the latent dementia phenotype "δ" and its various composite "homologs". We have explored δ's blood-based protein biomarkers in the Texas Alzheimer's Research and Care Consortium (TARCC) study. However, it would be convenient to replicate those associations in the Alzheimer's Disease Neuroimaging Initiative (ADNI). To this end, we have engineered a δ homolog from observed cognitive performance measures common to both projects. Our findings were replicated in randomly selected 50% splits of TARCC data (Group 1, N = 1,747; Group 2, N = 1,755), and then independently in ADNI (N = 1,737). The new δ homolog, i.e., "dT2A" (d-TARCC to ADNI), fit the data of both studies well, and was strongly correlated with dementia severity, as rated by the Clinical Dementia Rating Scale "sum of boxes" (TARCC: r = 0.99, p < 0.001; ADNI: r = 0.96, p < 0.001). dT2A achieved an area under the receiver operating characteristic curve of 0.981 (0.976-0.985) for the discrimination of Alzheimer's disease from normal controls in TARCC, and 0.988 (0.983-0.993) in ADNI. dT2A is the 12th δ homolog published to date, and opens the door to independent replications across these and similar studies.
Collapse
Affiliation(s)
- Donald R Royall
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA
- Department of Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans' Health System Audie L. Murphy Division GRECC, San Antonio, TX, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
| |
Collapse
|
15
|
Royall DR, Palmer RF. δ Scores Identify Subsets of "Mild Cognitive Impairment" with Variable Conversion Risks. J Alzheimers Dis 2019; 70:199-210. [PMID: 31127788 DOI: 10.3233/jad-190266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The latent variable "δ" (for "dementia) is a transdiagnostic measure of dementia severity. δ can be reified and applied to individuals as a composite "d-score". Like Spearman's general intelligence factor "g", δ can be constructed from almost any cognitive battery. So many are available that we must further distinguish each composite as a δ "homolog". Fourteen have been validated. All are strongly associated with dementia severity and potentially with mild cognitive impairment (MCI) conversion. OBJECTIVES To assess δ's impact on MCI conversion risk. METHODS A new δ homolog (dDx) was constructed in 1,230 Mexican-American (MA) and 2,215 non-Hispanic White (NHW) participants in the Texas Alzheimer's Research and Care Consortium (TARCC). 1,445 normal controls (NC) and 723 MCI were followed annually for up to 6 years. RESULTS Each SD decrease in the dDx score increased the risk of conversion sixteen-fold [OR = 16.39 (CI: 5.0-52.6)]. Cases below the optimal diagnostic threshold for Alzheimer's disease (AD) versus NC were labeled as having a functionally salient cognitive impairment (FSCI). Such cases were at a 73-fold increase risk of a diagnosis of AD [OR = 73.19 (95% CI: 58.3-92.0)]. However, 25.6% of MCI cases were also FSCI(+). They accounted disproportionately for prospective conversions. Age <80 years, the absence of an ɛ4 allele, <12 years of education, and MA ethnicity independently increased the risk of diagnosing FSCI as MCI. CONCLUSION A sizable minority of MCI cases may be misdiagnosed and they account disproportionately for AD conversions.
Collapse
Affiliation(s)
- Donald R Royall
- Departments of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA
- Departments of Medicine, The University of Texas Health Science Center, San Antonio, TX, USA
- Departments of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans' Health System Audie L. Murphy Division GRECC, San Antonio, TX, USA
| | - Raymond F Palmer
- Departments of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, TX, USA
| |
Collapse
|
16
|
Tao Q, Ang TFA, DeCarli C, Auerbach SH, Devine S, Stein TD, Zhang X, Massaro J, Au R, Qiu WQ. Association of Chronic Low-grade Inflammation With Risk of Alzheimer Disease in ApoE4 Carriers. JAMA Netw Open 2018; 1:e183597. [PMID: 30646251 PMCID: PMC6324596 DOI: 10.1001/jamanetworkopen.2018.3597] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/21/2018] [Indexed: 12/31/2022] Open
Abstract
Importance The association between peripheral inflammatory biomarkers and Alzheimer disease (AD) is not consistent in the literature. It is possible that chronic inflammation, rather than 1 episode of inflammation, interacts with genetic vulnerability to increase the risk for AD. Objective To study the interaction between the apolipoprotein E (ApoE) genotype and chronic low-grade inflammation and its association with the incidence of AD. Design, Setting, and Participants In this cohort study, data from 2656 members of the Framingham Heart Study offspring cohort (Generation 2; August 13, 1971-November 27, 2017) were evaluated, including longitudinal measures of serum C-reactive protein (CRP), diagnoses of incident dementia including AD, and brain volume. Chronic low-grade inflammation was defined as having CRP at a high cutoff level at a minimum of 2 time points. Statistical analysis was performed from December 1, 1979, to December 31, 2015. Main Outcomes and Measures Development of AD and brain volumes. Results Of the 3130 eligible participants, 2656 (84.9%; 1227 men and 1429 women; mean [SD] age at last CRP measurement, 61.6 [9.5] years) with both ApoE status and longitudinal CRP measurements were included in this study analysis. Median (interquartile range) CRP levels increased with mean (SD) age (43.3 [9.6] years, 0.95 mg/L [0.40-2.35 mg/L] vs 59.1 [9.6] years, 2.04 mg/L [0.93-4.75 mg/L] vs 61.6 [9.5] years, 2.21 mg/L [1.05-5.12 mg/L]; P < .001), but less so among those with ApoE4 alleles, followed by ApoE3 then ApoE2 genotypes. During the 17 years of follow-up, 194 individuals (7.3%) developed dementia, 152 (78.4%) of whom had AD. ApoE4 coupled with chronic low-grade inflammation, defined as a CRP level of 8 mg/L or higher, was associated with an increased risk of AD, especially in the absence of cardiovascular diseases (hazard ratio, 6.63; 95% CI, 1.80-24.50; P = .005), as well as an increased risk of earlier disease onset compared with ApoE4 carriers without chronic inflammation (hazard ratio, 3.52; 95% CI, 1.27-9.75; P = .009). This phenomenon was not observed among ApoE3 and ApoE2 carriers with chronic low-grade inflammation. Finally, a subset of 1761 individuals (66.3%) underwent brain magnetic resonance imaging, and the interaction between ApoE4 and chronic low-grade inflammation was associated with brain atrophy in the temporal lobe (β = -0.88, SE = 0.22; P < .001) and hippocampus (β = -0.04, SE = 0.01; P = .005), after adjusting for confounders. Conclusions and Relevance In this study, peripheral chronic low-grade inflammation in participants with ApoE4 was associated with shortened latency for onset of AD. Rigorously treating chronic systemic inflammation based on genetic risk could be effective for the prevention and intervention of AD.
Collapse
Affiliation(s)
- Qiushan Tao
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
| | - Ting Fang Alvin Ang
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts
| | - Charles DeCarli
- Alzheimer’s Disease Center, University of California Davis Medical Center, Sacramento
| | - Sanford H. Auerbach
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts
| | - Sheral Devine
- Framingham Heart Study, Boston University School of Medicine, Boston, Massachusetts
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts
| | - Thor D. Stein
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts
- Department of Pathology, Veterans Affairs Boston Healthcare System, Boston, Massachusetts
- Alzheimer’s Disease Center, Boston University School of Medicine, Boston, Massachusetts
| | - Xiaoling Zhang
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Joseph Massaro
- Framingham Heart Study, Boston University School of Medicine, Boston, Massachusetts
- Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts
| | - Rhoda Au
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts
- Framingham Heart Study, Boston University School of Medicine, Boston, Massachusetts
- Alzheimer’s Disease Center, Boston University School of Medicine, Boston, Massachusetts
| | - Wei Qiao Qiu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts
- Alzheimer’s Disease Center, Boston University School of Medicine, Boston, Massachusetts
| |
Collapse
|
17
|
Royall DR, Al-Rubaye S, Bishnoi R, Palmer RF. Serum proteins mediate depression's association with dementia. PLoS One 2017; 12:e0175790. [PMID: 28594820 PMCID: PMC5464526 DOI: 10.1371/journal.pone.0175790] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/31/2017] [Indexed: 01/08/2023] Open
Abstract
The latent variable "δ" (for "dementia") uniquely explains dementia severity. Depressive symptoms are independent predictors of δ. We explored 115 serum proteins as potential causal mediators of the effect of depressive symptoms on δ in a large, ethnically diverse, longitudinal cohort. All models were adjusted for age, apolipoprotein E, education, ethnicity, gender, hemoglobin A1c, and homocysteine, and replicated in randomly selected 50% subsets. Alpha1-antitrypsin (A1AT), FAS, Heparin-binding EGF-like Growth Factor (HB-EGF), Insulin-like Growth Factor-1 (IGF-1), Luteinizing Hormone (LH), Macrophage Inflammatory Protein type 1 alpha (MIP-1α), Resitin, S100b, Tissue Inhibitor of Metalloproteinase type 1 (TIMP-1), and Vascular Cell Adhesion Molecule type 1 (VCAM-1) each were partial mediators of depression's association with δ. These proteins may offer targets for the treatment of depression's specific effect on dementia severity and Alzheimer's Disease (AD) conversion risk.
Collapse
Affiliation(s)
- Donald R. Royall
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
- South Texas Veterans’ Health System Audie L. Murphy Division Geriatric Research Education and Clinical Care Center, San Antonio, Texas, United States of America
| | - Safa Al-Rubaye
- Department of Psychiatry, the University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Ram Bishnoi
- Department of Psychiatry, the Medical College of Georgia, Augusta, Georgia, United States of America
| | - Raymond F. Palmer
- Department of Family and Community Medicine, the University of Texas Health Science Center, San Antonio, Texas, United States of America
| |
Collapse
|