%0 Journal Article %J J Alzheimers Dis %D 2023 %T Association of Interleukin-6 and Interleukin-8 with Cognitive Decline in an Asian Memory Clinic Population. %A Teoh, Nicole Shu Ning %A Gyanwali, Bibek %A Lai, Mitchell K P %A Chai, Yuek Ling %A Chong, Joyce R %A Chong, Eddie Jun Yi %A Chen, Christopher %A Tan, Chuen Seng %A Hilal, Saima %K Aged %K Biomarkers %K Canada %K Cognition %K Cognitive Dysfunction %K Female %K Humans %K Interleukin-6 %K Interleukin-8 %K Male %K Neuroinflammatory Diseases %K Neuropsychological Tests %X

BACKGROUND: Neuroinflammation has been postulated to play an important role in cognitive impairment, cognitive decline, and dementia. Inflammatory biomarkers such as interleukin-6 (IL-6) and IL-8 are found to be associated with the neuro-inflammatory process and worse cognitive function. However, it is unknown whether these interleukins are associated with long-term cognitive function.

OBJECTIVE: To investigate the association of baseline IL-6 and IL-8 with cognitive function at baseline as well as its association with cognitive decline over five-year follow-up.

METHODS: 387 patients were recruited from an ongoing memory clinic-based study who underwent comprehensive physical, medical, neuropsychological and blood assessments together with brain MRI. IL-6 and IL-8 were measured using LUMINEX assays. The National Institute of Neurological Disorders and Stroke-Canadian Stroke Network neuropsychological battery was used to assess cognitive decline across multiple domains.

RESULTS: Among the 387 (mean age = 72.9 years and 53.7% males) participants, 322 had at least two follow-up assessments and were included in the longitudinal analysis. Negative linear trend associations were found between tertiles of IL-8 with baseline global cognition (p-trend< 0.001), attention (p-trend = 0.005), executive function (p-trend< 0.001), and visuospatial function (p-trend = 0.002) domains. No association was found between baseline IL-8 and cognitive decline. IL-6 was not associated with both baseline and follow-up cognition.

CONCLUSION: IL-8 was associated with worse cognition especially in attention, executive function, and visuospatial function, suggesting the role of neuroinflammation in cognitive impairment. Hence, blood inflammatory biomarkers may be useful indicators in identifying patients at risk of cognitive impairment and warrant consideration for inclusion in treatment trials.

%B J Alzheimers Dis %V 92 %P 445-455 %8 2023 %G eng %N 2 %R 10.3233/JAD-220971 %0 Journal Article %J J Alzheimers Dis %D 2020 %T Influence of Comorbidity of Cerebrovascular Disease and Amyloid-β on Alzheimer's Disease. %A Yassi, Nawaf %A Hilal, Saima %A Xia, Ying %A Lim, Yen Ying %A Watson, Rosie %A Kuijf, Hugo %A Fowler, Christopher %A Yates, Paul %A Maruff, Paul %A Martins, Ralph %A Ames, David %A Chen, Christopher %A Rowe, Christopher %A Villemagne, Victor %A Salvado, Olivier %A Desmond, Patricia M %A Masters, Colin L %X

BACKGROUND: Quantifying the contribution of cerebrovascular disease to the clinical and pathological profile of Alzheimer's disease is challenging.

OBJECTIVE: We aimed to determine the influence of cerebrovascular disease, amyloid-β (Aβ), and their comorbidity on cognitive decline, hippocampal atrophy, and Aβ deposition, by evaluating data from the Australian Imaging, Biomarker and Lifestyle Study of Ageing.

METHODS: Two-hundred and eighteen participants underwent Aβ PET, MRI, and cognitive assessment at 18-month intervals for up to 90 months. Aβ status was determined on baseline PET. Participants were also classified as V + on baseline MRI if they had≥1 large cortical infarcts, subcortical infarcts, or cortical cerebral microinfarcts; or white matter hyperintensity volume greater than the 90th percentile of healthy controls. Linear mixed models were conducted comparing slopes of change in cognition, hippocampal volume, and Aβ load between the four resultant groups.

RESULTS: Mean age at baseline was 74 years (range 59-96). One-hundred and fifteen participants were cognitively normal, 54 had mild cognitive impairment, and 49 had Alzheimer's disease. Compared to the Aβ-/V- group, the Aβ+/V- and Aβ+/V+groups showed significantly faster cognitive decline and hippocampal atrophy over 90 months. V + status was associated with greater cognitive decline (Cohen's d = 0.85, p < 0.001) and hippocampal atrophy (d = 2.05, p < 0.001) in the Aβ+group but not in the Aβ- group. V + status was not associated with Aβ accumulation in any group.

CONCLUSION: Comorbidity of cerebrovascular disease and Aβ was associated with cognitive decline and neurodegeneration. Cerebrovascular disease was not associated with the rate of Aβ accumulation.

%B J Alzheimers Dis %V 73 %P 897-907 %8 2020 Feb 04 %G eng %N 3 %R 10.3233/JAD-191028 %0 Journal Article %J J Alzheimers Dis %D 2019 %T Risk Factors for and Clinical Relevance of Incident and Progression of Cerebral Small Vessel Disease Markers in an Asian Memory Clinic Population. %A Gyanwali, Bibek %A Shaik, Muhammad Amin %A Tan, Boon Yeow %A Venketasubramanian, Narayanaswamy %A Chen, Christopher %A Hilal, Saima %X

BACKGROUND: Cerebral small vessel disease (SVD) is one of the major contributors to cognitive impairment and dementia. However, data on the incidence and progression of SVD in an Asian population are lacking.

OBJECTIVE: The present study aims to investigate the incidence, progression, associated risk factors, and clinical relevance of SVD in a memory clinic setting.

METHODS: A prospective case-control study, where 346 patients underwent repeated brain MRI with a mean interval of 24.5 months, accessing white matter hyperintensities (WMH), lacunes and cerebral microbleeds (CMBs). Severity of cognitive impairment was assessed using Clinical Dementia Rating scale and change in clinical diagnosis. Data on demographics, vascular risk factors, and clinical history were collected at baseline.

RESULTS: The prevalence of significant WMH (Fazekas ≥2) was 56.6% at baseline which progressed to 59.0% at follow-up. Overall prevalence of CMBs increased from 42.2% to 47.4% (9% new cases) and lacunes increased from 31.8% to 33.2% (2.1% new cases). Hypertension was associated with WMH progression (OR: 1.78, 95% CI: 1.01, 2.99) and increasing age was associated with incident CMBs (OR: 1.04, 95% CI: 1.01, 1.08). Moreover, the use of lipid-lowering medications decreased the incidence of lacunes (OR: 0.15, 95% CI: 0.04, 0.61). The major risk factor for incident SVD was baseline SVD lesion load. WMH progression was associated with increased severity of cognitive impairment (OR: 1.95, 95% CI: 1.16, 3.23).

CONCLUSION: Vascular risk factors and baseline severity of SVD lesion load were associated with progression of SVD. Furthermore, WMH progression was linked with increased severity of cognitive impairment. Future studies should be aimed to slow cognitive deterioration by preventing SVD related brain damage by targeting vascular risk factors.

%B J Alzheimers Dis %V 67 %P 1209-1219 %8 2019 %G eng %N 4 %R 10.3233/JAD-180911 %0 Journal Article %J J Alzheimers Dis %D 2019 %T Telomere Length and the Risk of Alzheimer's Disease: The Rotterdam Study. %A Fani, Lana %A Hilal, Saima %A Sedaghat, Sanaz %A Broer, Linda %A Licher, Silvan %A Arp, Pascal P %A van Meurs, Joyce B J %A Ikram, M Kamran %A Ikram, M Arfan %X

There is a wide interest in biomarkers that capture the burden of detrimental factors as these accumulate with the passage of time, i.e., increasing age. Telomere length has received considerable attention as such a marker, because it is easily quantified and it may aid in disentangling the etiology of dementia or serve as predictive marker. We determined the association of telomere length with risk of Alzheimer's disease and all-cause dementia in a population-based setting. Within the Rotterdam Study, we performed quantitative PCR to measure mean leukocyte telomere length in blood. We determined the association of telomere length with risk of Alzheimer's disease until 2016, using Cox regression models. Of 1,961 participants (mean age 71.4±9.3 years, 57.1% women) with a median follow-up of 8.3 years, 237 individuals were diagnosed with Alzheimer's disease. We found a U-shaped association between telomere length and risk of Alzheimer's disease: compared to the middle tertile the adjusted hazard ratio was 1.59 (95% confidence interval (CI), 1.13-2.23) for the lowest tertile and 1.47 (1.03-2.10) for the highest tertile. Results were similarly U-shaped but slightly attenuated for all-cause dementia. In conclusion, shorter and longer telomere length are both associated with an increased risk of Alzheimer's disease in the general population.

%B J Alzheimers Dis %V 73 %P 707-714 %8 2020 Jan 21 %G eng %N 2 %R 10.3233/JAD-190759 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Homocysteine and Cerebral Atrophy: The Epidemiology of Dementia in Singapore Study. %A Tan, Bryce %A Venketasubramanian, Narayanaswamy %A Vrooman, Henri %A Cheng, Ching-Yu %A Wong, Tien Yin %A Ikram, Mohammad Kamran %A Chen, Christopher %A Hilal, Saima %K Aged %K Atrophy %K Biomarkers %K Dementia %K Female %K Homocysteine %K Humans %K Magnetic Resonance Imaging %K Male %K Middle Aged %K Organ Size %K Risk Factors %K Singapore %K White Matter %X

BACKGROUND: Plasma homocysteine levels are increasingly studied as a potential risk factor for dementia. Elevated homocysteine levels have been linked with gray and white matter volume reduction among individuals with mild cognitive impairment and Alzheimer's disease. However, the effects of homocysteine on brain changes in preclinical stages of dementia remain unexplored.

OBJECTIVE: To examine the association of elevated homocysteine levels with markers of neurodegeneration, i.e., white and gray matter volume in an elderly population.

METHODS: The study included 768 participants (mean age: 69.6±6.5 years, 51.3% women) from the Epidemiology of Dementia In Singapore study. Participants underwent a brain MRI scan and blood tests. Serum homocysteine was measured using competitive immunoassay. Cortical thickness and subcortical structural volume were quantified using FreeSurfer whereas white matter volume was quantified using a previous validated method.

RESULTS: Higher homocysteine levels were significantly associated with decreased global white matter volume [mean difference (β) in volume (ml) per micromole per liter (μmol/l) increase in homocysteine levels: - 0.555, 95% Confidence Interval (CI): - 0.873; - 0.237], decreased parietal cortical thickness [β in thickness (μm) per μmol/l increase in homocysteine levels:- 1.429, 95% CI: - 2.781; - 0.077], and smaller volumes of the thalamus [β: - 0.017, 95% CI: - 0.026; - 0.008], brainstem [β: - 0.037, 95% CI: - 0.058; - 0.016], and accumbens [β: - 0.004, 95% CI: - 0.006; - 0.002].

CONCLUSION: Higher homocysteine levels were associated with cerebral atrophy. Further studies are required to assess whether lowering plasma homocysteine levels may prevent neurodegenerative changes or delay progression of clinical symptoms before the development of dementia.

%B J Alzheimers Dis %V 62 %P 877-885 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29480177?dopt=Abstract %R 10.3233/JAD-170796 %0 Journal Article %J J Alzheimers Dis %D 2017 %T Plasma Amyloid-β Levels, Cerebral Small Vessel Disease, and Cognition: The Rotterdam Study. %A Hilal, Saima %A Akoudad, Saloua %A van Duijn, Cornelia M %A Niessen, Wiro J %A Verbeek, Marcel M %A Vanderstichele, Hugo %A Stoops, Erik %A Ikram, M Arfan %A Vernooij, Meike W %X

BACKGROUND: Plasma amyloid-β (Aβ) levels are increasingly studied as a potential, accessible marker of cognitive impairment and dementia. The most common plasma Aβ isoforms, i.e., Aβ1-40 and Aβ1-42 have been linked with risk of Alzheimer's disease. However, it remains under-explored whether plasma Aβ levels including novel Aβ1-38 relate to vascular brain disease and cognition in a preclinical-phase of dementiaObjective:To examine the association of plasma Aβ levels (i.e., Aβ1-38, Aβ1-40, and Aβ1-42) with markers of cerebral small vessel disease (SVD) and cognition in a large population-based setting.

METHODS: We analyzed plasma Aβ1 levels in 1201 subjects from two independent cohorts of the Rotterdam Study. Markers of SVD [lacunes, white matter hyperintensity (WMH) volume] were assessed on brain MRI (1.5T). Cognition was assessed by a detailed neuropsychological battery. In each cohort, the association of Aβ levels with SVD and cognition was performed using regression models. Estimates were then pooled across cohorts using inverse variance meta-analysis with fixed effects.

RESULTS: Higher levels of plasma Aβ1-38, Aβ1-40, Aβ1-42, and Aβ1-40/ Aβ1-42 ratio were associated with increasing lacunar and microbleeds counts. Moreover, higher levels of Aβ1-40 and Aβ1-40/ Aβ1-42 were significantly associated with larger WMH volumes. With regard to cognition, a higher level of Aβ1-38 Aβ1-40 and Aβ1-40/ Aβ1-42 was related to worse performance on cognitive test specifically in memory domain.

CONCLUSION: Higher plasma levels of Aβ levels are associated with subclinical markers of vascular disease and poorer memory. Plasma Aβ levels thus mark the presence of vascular brain pathology.

%B J Alzheimers Dis %V 60 %P 977-987 %8 2017 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/28984600?dopt=Abstract %R 10.3233/JAD-170458 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Apolipoprotein ɛ4 is Associated with Dementia and Cognitive Impairment Predominantly Due to Alzheimer's Disease and Not with Vascular Cognitive Impairment: A Singapore-Based Cohort. %A Chai, Yuek Ling %A Yeo, Hazel Kai-Hui %A Wang, Jiehao %A Hilal, Saima %A Ikram, Mohammad Kamran %A Venketasubramanian, Narayanaswamy %A Wong, Boon-Seng %A Chen, Christopher Li-Hsian %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Analysis of Variance %K Apolipoprotein E4 %K Cognition Disorders %K Cohort Studies %K Dementia %K Female %K Genetic Association Studies %K Genotype %K Humans %K Male %K Middle Aged %K Neuroimaging %K Neuropsychological Tests %K Psychiatric Status Rating Scales %K Singapore %K Vascular Diseases %X

BACKGROUND AND OBJECTIVE: While the association for apolipoprotein ɛ4 allele (APOE4) with Alzheimer's disease (AD) has been consistently confirmed, the association with vascular cognitive impairment (VCI) is unclear. We therefore explored the relationship of APOE with both AD and cerebrovascular disease (CeVD) by examining the prevalence of APOE4 in AD, AD with CeVD and vascular dementia (VaD), as well as in cognitive impairment no dementia (CIND) with and without CeVD.

METHODS: We performed a case-control study with subjects recruited from memory clinics and the community. All subjects underwent standardized brain neuroimaging, clinical and neuropsychological assessments, following which they were classified using research criteria.

RESULTS: A total of 411 subjects; 92 controls with no cognitive impairment (NCI), 77 CIND without CeVD, 87 CIND with CeVD, 55 AD without CeVD, 68 AD with CeVD, and 32 VaD patients were recruited. Compared to NCI (16.3%), the prevalence of APOE4 carriers was significantly higher only in CIND (37.7%) and AD in the absence of CeVD (45.5%), but not in the three subgroups of VCI, namely CIND with CeVD (20.7%), AD with CeVD (27.9%) and VaD (25.0%). Logistic regression analyses also showed that APOE4 carriers were more likely to have CIND without CeVD (Odds Ratio [OR]: 3.34; 95% Confidence Interval [CI]: 1.59-7.03) and AD without CeVD (OR: 7.21; 95% CI: 2.74-18.98), but no such association was observed in the VCI subgroups.

CONCLUSION: APOE4 is significantly associated with dementia and CIND due to AD pathology, but not with VCI.

%B J Alzheimers Dis %V 51 %P 1111-8 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26923016?dopt=Abstract %R 10.3233/JAD-150902 %0 Journal Article %J J Alzheimers Dis %D 2016 %T The Association Between Retinal Neuronal Layer and Brain Structure is Disrupted in Patients with Cognitive Impairment and Alzheimer's Disease. %A Liu, Siwei %A Ong, Yi-Ting %A Hilal, Saima %A Loke, Yng Miin %A Wong, Tien Y %A Chen, Christopher Li-Hsian %A Cheung, Carol Y %A Zhou, Juan %X

Both healthy and pathological aging due to Alzheimer's disease (AD) are associated with decreased brain grey matter volume (GMV) and disrupted white matter (WM) microstructure. Thinner macular ganglion cell-inner plexiform layer (GC-IPL) measured by spectral-domain optical coherence tomography has been reported in patients with AD and mild cognitive impairment. Emerging evidence suggested a link between thinner GC-IPL and lower GMV in subjects with no dementia using region-of-interest-based approach. However, it remains unknown whether GC-IPL thickness is associated with brain WM microstructure and how such association differed between normal and cognitively impaired subjects. Here, for subjects with no cognitive impairment (NCI), thinner GC-IPL was associated with lower WM microstructure integrity in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, corticospinal tracts, anterior thalamic radiation, and cingulum regions, while it was weakly associated with lower GMV in visual cortex and cerebellum. Nevertheless, these retina-brain associations were disrupted in the presence of cognitive impairment. Correlations between GMV and GC-IPL were lost in patients with cognitive impairment but no dementia (CIND) and AD patients. GC-IPL was related to WM microstructural disruption in similar regions with decreased significance. In contrast, lower WM microstructure integrity in the fornix showed a trend of correlation with thinner GC-IPL in both CIND and AD but not NCI. Collectively, our findings suggest the possible physiological retina-brain relationship in healthy aging, which might be disrupted by disease-induced changes in patients with cognitive impairment. Longitudinal study with larger patient sample should follow to confirm the disease mechanism behind these retina-brain relationship changes.

%B J Alzheimers Dis %V 54 %P 585-95 %8 2016 Sep 06 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/27567815?dopt=Abstract %R 10.3233/JAD-160067 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Validation of the Total Cerebrovascular Disease Burden Scale in a Community Sample. %A Xu, Xin %A Hilal, Saima %A Collinson, Simon L %A Chan, Qun Lin %A Yi Chong, Eddie Jun %A Ikram, Mohammad Kamran %A Venketasubramanian, Narayanaswamy %A Cheng, Ching-Yu %A Wong, Tien Yin %A Chen, Christopher Li-Hsian %X

BACKGROUND: A total cerebrovascular disease (CeVD) burden scale was previously constructed and an inverse association of CeVD burden and cognition was found. However, the generalizability of the CeVD scale has not been examined.

OBJECTIVE: The objective was to validate the previously constructed total CeVD burden scale by establishing its association with cognitive function and dementia diagnosis in a community sample.

METHODS: Eligible participants were assessed on an extensive neuropsychological battery and underwent MRI scans. The total CeVD scale, comprising markers of both small- and large-vessel diseases, was derived according to previously described criteria. Association of total CeVD burden with global and domain-based cognitive performance and dementia diagnostic utility of the scale was established.

RESULTS: A total of 863 participants were included in the analysis. A stepwise association of CeVD burden score with global and domain-specific cognitive function was found. Per score increase on the total CeVD burden scale was associated with 3.6 (95% CI = 2.1-6.4) times higher odds of dementia compared to dementia-free.

DISCUSSION: The total CeVD burden scale is associated with cognition and dementia in a community sample. Longitudinal studies are required to establish the predictive ability of this scale.

%B J Alzheimers Dis %V 52 %P 1021-8 %8 2016 Apr 12 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/27079726?dopt=Abstract %R 10.3233/JAD-160139