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Inverse Relationship between Apolipoprotein A-I and Cerebral White Matter Lesions: A Cross-Sectional Study in Middle-Aged and Elderly Subjects

  • Ze-Gang Yin,

    Affiliation Department of Neurology, Daping Hospital and Institute of Field Surgery, Third Military Medical University, Chongqing, China

  • Ling Li,

    Affiliation Department of Neurology, Daping Hospital and Institute of Field Surgery, Third Military Medical University, Chongqing, China

  • Min Cui,

    Affiliation Department of Neurology, Wuhan General Hospital of PLA, Wuhan, Hubei, China

  • Shi-Ming Zhou,

    Affiliation Department of Neurology, Daping Hospital and Institute of Field Surgery, Third Military Medical University, Chongqing, China

  • Ming-Ming Yu,

    Affiliation Department of Neurology, Daping Hospital and Institute of Field Surgery, Third Military Medical University, Chongqing, China

  • Hua-Dong Zhou

    zhouhuad@163.com

    Affiliation Department of Neurology, Daping Hospital and Institute of Field Surgery, Third Military Medical University, Chongqing, China

Inverse Relationship between Apolipoprotein A-I and Cerebral White Matter Lesions: A Cross-Sectional Study in Middle-Aged and Elderly Subjects

  • Ze-Gang Yin, 
  • Ling Li, 
  • Min Cui, 
  • Shi-Ming Zhou, 
  • Ming-Ming Yu, 
  • Hua-Dong Zhou
PLOS
x

Abstract

Background

Apolipoprotein A-I (apoA-I), the major protein for high density lipoprotein, is essential for reverse cholesterol transport. Decreased serum levels of apoA-I have been reported to correlate with subcortical infarction and dementia, both of which are highly related to white matter lesions (WMLs). However, the association between apoA-I and WMLs has never been investigated. In this study, we sought to investigate the association between apoA-I and the presence of WMLs in middle-aged and elderly subjects.

Methods

Consecutive patients aged 50 years and older of our department were prospectively enrolled in this study (n = 1282, 606 men and 676 women, 65.9±9.4 years). All participants underwent MRI scans to assess the presence and severity of WMLs. Multivariate logistic regression analyses were performed to examine the association of apoA-I with WMLs.

Results

Patients with WMLs were older and showed significantly higher proportion of male sex, hypertension, diabetes mellitus, previous stroke, and coronary heart disease whereas levels of total cholesterol, high density lipoprotein cholesterol, and apoA-I were lower. After adjustment for potential confounders, the lowest apoA-I quartile was independently associated with an increased risk of WMLs (odds ratio: 1.87, 95% confidence interval: 1.29–2.72). In sex-specific analyses, this relationship was observed only in women.

Conclusions

Our findings demonstrated that apoA-I was inversely associated with the presence of WMLs in middle-aged and elderly subjects. This results suggest that therapies which increase apoA-I concentration may be beneficial to reduce the risk of WMLs, dementia and stroke.

Introduction

Cerebral white matter lesions (WMLs), also known as leukoaraiosis, are frequently observed on brain magnetic resonance imaging (MRI) in older individuals. Accumulating evidence suggests that WMLs have substantial clinical impact through associations with dementia, disability, depression, stroke, and mortality [1], [2]. WMLs reflect multiple pathologic changes, including loss and deformation of myelin sheath, changes in vessel wall permeability, disruption of the blood-brain barrier, hypoperfusion attributable to altered cerebrovascular autoregulation, fluid shift from the ventricles and gliosis [3], [4]. Whereas advanced age and hypertension are the most widely accepted risk factors for WMLs, the current understanding of other risk factors for WMLs remains less clear. The role of lipids in the pathogenesis of WMLs is controversial in former studies. Some studies have shown that low levels of high density lipoprotein (HDL) cholesterol and hypertriglyceridemia may increase the risk of WMLs [5], [6]. However, other authors have not consistently shown similar associations [7], [8].

Apolipoprotein A-I (apoA-I) is the major protein component of HDL and plays an important role in transporting excess cholesterol from peripheral cells to the liver [9]. Besides the atheroprotective effect, apoA-I also manifests anti-inflammatory and antioxidant effects [10]. Recently, decreased serum apoA-I levels have been reported to increase the risk of deep subcortical infarction [11], which often coexists with WMLs in brains [12]. Furthermore, the Honolulu-Asia aging study has found an inverse relation between apoA-I and dementia [13]. However, the association between apoA-I and the presence of WMLs has never been investigated.

Thus, in the present cross-sectional study, we aimed to evaluate the association of apoA-I with the presence of WMLs in middle-aged and elderly subjects. This could improve our understanding of the pathophysiology underlying this highly prevalent cerebrovascular disease.

Methods

Ethics Statement

The study protocols were approved by Institutional Review Board of the Third Military Medical University and performed in accordance with the Declaration of Helsinki. All participants provided written informed consent prior to their inclusion in the study.

Study population

Consecutive inpatients admitted to the department of neurology of Daping Hospital in the city of Chongqing from June 2012 to June 2013 were prospectively enrolled in this study. All patients were proposed to undergo brain MRI scans. Inclusion criteria were (1) aged 50 years and older; (2) ability to understand the aim of the study and provide written informed consent. The following patients were excluded: (1) patients with leukoencephalopathy of nonvascular origin (immunological-demyelinating, toxic, infectious, other); (2) patients with brain tumors, dementia, psychoses; (3) patients who had contraindications for MRI scans or refused to undergo cerebral MRI; (4) patients who had been using lipid-lowering medications before admission; (5) patients who refused to undergo lipids tests.

Clinical information collection

Every participant underwent a standardized clinical examination and interview using a detailed questionnaire survey to obtain information including demographic data, past medical history, current cigarette smoking status, and the use of antihypertensive medications, lipid-lowering medications, and oral hypoglycemic agents or insulin. Body mass index was calculated as the weight divided by the square of the height (kg/m2). Blood pressure was determined using an aneroid sphygmomanometer with the patients in a sitting position after relaxing for at least 10 minutes, and the mean of two measurements was used. Blood samples were drawn in the morning after an overnight fast and sent to the clinical laboratory of Daping Hospital for the measurement of serum indices. The levels of fasting blood glucose (FBG), total cholesterol (TC), triglyceride, HDL cholesterol, and low density lipoprotein cholesterol were measured by standard enzymatic techniques. The levels of apoA-I and apoB were measured by the immunoturbidimetric method using a DxC800 chemistry analyzer (Beckman Coulter Inc., Brea, California, United States). The intra- and inter-assay coefficient of variation for apoA-I were 1.9% and 2.3%, respectively. Hypertension was defined as systolic/diastolic blood pressure measures greater than 140/90 mmHg, or current treatment with antihypertensive medications. Diabetes mellitus was defined as FBG ≥7.0 mmol/L or current treatment with hypoglycemic agents or insulin. In addition, a physician's diagnostic report of cardiovascular disease, including coronary heart disease (CHD) or previous stroke, was gathered for each participant.

MRI scans and WMLs grading

MRI was performed following a standard protocol including T1- (TR/TE: 450/8.9 ms) and T2- (TR/TE: 5000/87 ms) weighted and fluid attenuated inversion recovery (FLAIR, TR/TE: 8500/88 ms, inversion time: 2000 ms) sequences using a 1.5 T magnet (Signa EXCITE HD 1.5T, General Electric, USA). The degree of WMLs severity was rated on FLAIR by two trained investigators (Yin and Cui) who were blind to the clinical data, using the modified visual scale of Fazekas et al [14]. Disagreements of imaging analysis were resolved by consensus. Taking into account only deep and subcortical white matter, lesions were classified into three categories: mild  =  single lesions must be more than 3 mm and smaller than 10 mm, areas of grouped lesions must be smaller than 20 mm in any diameter; moderate  =  single lesions between 10 and 20 mm, areas of grouped lesions more than 20 mm in any diameter, no more than connecting bridges between individual lesions; severe  =  single lesions or confluent areas of hyperintensity 20 mm or more in any diameter [15].

Statistical analyses

Demographic data were expressed in percentages for categorical variables and compared using the chi-square test. Continuous variables were expressed as mean ± SD and compared with a Student t test for factors with a normal distribution or expressed as median and interquartile range and compared with the Mann-Whitney U test for factors that were not normally distributed. The relationship between apoA-I quartiles and severity of WMLs was evaluated by chi-square linear-by-linear association test. Multivariate logistic regression analyses were performed to determine whether the decreased serum apoA-I levels were independently associated with WMLs after adjustment for the potential confounders. The baseline variables having p<0.10 for the presence of WMLs in univariate analyses were selected to enter the multivariate models. Finally, we repeated all analyses excluding participants within the acute period of stroke (n = 220). Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. All p values were two-tailed, and values of p<0.05 were considered statistically significant. All statistical analyses were performed using SPSS18.0 for Windows (SPSS Inc., Chicago IL).

Results

1509 consecutive patients aged 50 years and older were admitted to the department of neurology of Daping Hospital from June 2012 to June 2013. We excluded 101 individuals who had contraindications for MRI scans or refused to undergo brain MRI, 14 who were with leukoencephalopathy of nonvascular origin, 35 who were diagnosed with brain tumors, dementia, or psychoses, 45 who had been using lipid-lowering medications before admission, and 32 who refused to undergo lipids tests. Finally, a total of 1282 patients were enrolled in the study. Among the 1282 patients, 587 complained of non-specific neurological symptoms (e.g., dizziness, vertigo, numbness and other symptoms), 220 of acute stroke, 102 of headache, 81 of sleep disorders, 65 of movement disorders, 125 of peripheral neuropathy and 102 of other neurological conditions.

The mean age of the study population was 65.9±9.4 years; 47.3% were men. Among the 1282 participants, mild WMLs was found in 486 (37.9%), moderate WMLs in 147 (11.5%), and severe WMLs in 91 (7.1%). Demographic characteristics of the study population are shown in Table 1. Patients with WMLs were older (p<0.001) and more likely to be male (p<0.001) in comparison with those without WMLs. Moreover, patients with WMLs showed significantly higher proportion of hypertension, diabetes mellitus, previous stroke, and CHD whereas levels of TC, HDL cholesterol, and apoA-I were lower.

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Table 1. Clinical characteristics of subjects with or without cerebral white matter lesions.

https://doi.org/10.1371/journal.pone.0097113.t001

Serum apoA-I levels ranged from 0.62 to 2.40 g/L for women and 0.47 to 2.22 g/L for men. They were higher for women than men (1.46±0.24 vs. 1.29±0.23 g/L; p<0.001). As shown in Figure 1, in women, those with WMLs had lower levels of apoA-I than those without WMLs (1.40±0.24 vs. 1.51±0.23 g/L; p<0.001). However, this difference was not observed between the two groups in men (1.28±0.24 vs. 1.30±0.22 g/L; p = 0.321). Patients were stratified into quartiles according to the serum apoA-I levels by sex. The sex-specific quartiles were ≤1.30, 1.31 to 1.46, 1.47 to 1.60, and ≥1.61 g/L for women while ≤1.13, 1.14 to 1.26, 1.27 to 1.42, and ≥1.43 g/L for men. As shown in Figure 2, patients with lower apoA-I quartiles were likely to have higher prevalence and severity of WMLs (p for trend <0.001).

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Figure 1. Box-plots of apoA-I values and their association WMLs in men and women.

ApoA-I, apolipoprotein A-I; WMLs: white matter lesions.

https://doi.org/10.1371/journal.pone.0097113.g001

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Figure 2. Presence and severity of WMLs according to apoA-I quartiles.

Values are percentages of patients. As levels of apoA-I increased, the presence and severity of WMLs increased (P for trend <0.001). ApoA-I, apolipoprotein A-I; WMLs: white matter lesions.

https://doi.org/10.1371/journal.pone.0097113.g002

Table 2 shows the results of the multivariate logistic regression model and the OR for each factor. After adjustment for age, sex, history of stroke, CHD, hypertension, and diabetes, patients with the lowest apoA-I quartile were approximately 1.9 times more likely to have WMLs, compared with those with the highest apoA-I quartile. When the apoA-I concentration entered the model as a continuous variable, this inverse relationship between apoA-I and WMLs remained significant (OR: 0.40, 95% CI: 0.23–0.70). In addition, age, previous stroke and hypertension were independently associated with an increased risk of WMLs (p<0.001 for all variables). In sex-specific analyses, the lowest apoA-I quartile still predicted higher prevalence of WMLs in women (OR: 3.46, 95% CI: 2.08–5.76), but not in men (Table 3). When the apoA-I concentration was added to the multivariate models as a continuous variable, the sex difference still existed (OR: 0.17, 95%CI: 0.08–0.36 for women; OR: 1.20, 95%CI: 0.52–2.77 for men).

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Table 3. Multivariate analyses of white matter lesions determinants stratified by sex.

https://doi.org/10.1371/journal.pone.0097113.t003

Furthermore, we repeated the multivariate adjusted logistic regression analyses after excluding 220 patients within the acute period of stroke, and found that the lowest apoA-I quartile remained an independent predictor for WMLs (OR: 2.13, 95% CI: 1.42–3.20). In addition, the effects of HDL cholesterol on WMLs were similar to those of apoA-I in multivariate logistic regression analyses (data not show). The Akaike information criterion (AIC) was used to compared the goodness of fit between the two models (one including apoA-I and the other including HDL cholesterol). As a result, the model with apoA-I showed a slightly better fit than the model using the HDL cholesterol levels (1441 vs. 1447 of the AIC value, respectively).

Discussion

In the current study carried out on middle-aged and elderly subjects, we investigated the associations of lipid profiles and apolipoproteins with the presence of WMLs, and found that patients with the lowest apoA-I quartile had approximately a 1.9 times increased risk for WMLs. This association was independent of age, sex, and vascular risk factors. Further analyses showed that this relationship existed only in women. These findings did not change after excluding 220 patients within the acute period of stroke. To the best of our knowledge, we first demonstrated that apoA-I was inversely associated with an increased risk of WMLs. This might provide a partial explanation of the previously observed association between decreased serum levels of apoA-I and dementia in elderly adults [13], [16].

Dyslipidemias are widely recognized as a risk factor for stroke [17], [18], and lipid-lowering therapies have demonstrated benefits in stroke prevention and prognosis [19], [20]. However, the association between serum lipids and WMLs remains inconsistent in former studies. For instance, Crisby et al. [6] reported that HDL cholesterol was inversely related to the risk of WMLs, in accord with our study. In contrast, a study investigating the association between metabolic syndrome components and WMLs found that hypertriglyceridemia, but not low level of HDL cholesterol, was an independent risk factor for WMLs [21]. Likewise, hypertriglyceridemia was significantly related to severe WMLs in a recent study [5]. This relationship, however, was not observed in our study. Furthermore, TC was an independent risk factor for WMLs in some studies [22], [23], but was protective against WMLs in two cohorts [24]. We found that subjects without WMLs had higher levels of TC, which suggested a protective role of TC against WMLs. However, this relationship between TC and WMLs was no longer significant after adjustment for potential confounding variables.

ApoA-I is essential for reverse transport of cholesterol from peripheral tissue to the liver [9]. It also has antioxidant and anti-inflammatory effects [10]. In contrast, apolipoprotein B (apoB) is a major structural protein for very low density-low density lipoprotein spectrum and reflects atherogenic potential [9]. The apoB/apoA-I ratio is increasingly recognized as a better predictor of cardiovascular disease than other traditional cholesterol measures [25], [26]. Very few reports from the literature are available to compare with our findings regarding apolipoproteins and WMLs. Cross-sectional data from the community-dwelling Austrian Stroke Prevention Study demonstrated that participants with microangiopathy-related cerebral damage had lower levels of apoA-I. However, decreased apoA-I concentration did not enter the final multivariate model [27]. In the present study, we observed that patients with WMLs had lower levels of apoA-I, compared with those without WMLs. The apoB levels, however, did not show significant difference between the two groups. These findings are consistent with a recent study, which reported that levels of apoA-I, but not apoB, were associated with deep subcortical infarction [11]. These results indicate that the effects of apolipoproteins on cerebral small vessel disease might differ from those on large vessel disease. Anti-inflammatory effects of apoA-I may play a more important role in preventing WMLs formation, than atheroprotective effects.

Although the exact mechanism underlying the inverse relationship between apoA-I and WMLs remains to be elucidated, there are some plausible explanations. First, the interaction of apoA-I with ATP-binding cassette transporter A1 (ABCA1) activates signal transducer and activator of transcription 3, which suppresses the production of inflammatory cytokines and ultimately inhibits the inflammatory response [28]. Biomarkers of inflammation such as interleukin-6, intercellular adhesion molecule, and C-reactive protein have been reported to be associated with the presence or progression of WMLs in population-based studies [29][31]. In animal model, neuroinflammation has also proved to be an important mechanism of white matter damage [32]. Second, apoA-I binds amyloid β (Aβ) and prevents Aβ-induced neurotoxicity [33], and apoA-I deficiency increases levels of deposited Aβ in the brain vessels [34]. These results suggest that apoA-I attenuates cerebral amyloid angiopathy, which is not only a hallmark of Alzheimer's disease [12], but also a predictor for WMLs [35], [36]. Third, apoA-I promotes reverse cholesterol transport through the macrophage ABCA1 and protects large vessels from atherosclerosis [37], which has been related to WMLs in several studies [38], [39]. Furthermore, apoA-I may directly protect small vessels from microatheroma which is a manifestation of arteriolosclerosis, the primary pathological feature of small vessel disease [12].

Additionally, we found that the lowest apoA-I quartile was associated with WMLs only in women. Similarly, a longitudinal study has found that higher HDL cholesterol predicted better maintenance of cognitive abilities in women, but not in men [40]. The mechanisms underlying the sex differences are unknown. We cannot rule out a possible effect modification of sex hormones in the association. Sex differences should be considered in future studies of the effect of lipids on cerebral small vessel disease.

The present study has several limitations. First, the present study was cross-sectional and could not determine the exact causality between decreased serum apoA-I concentration and WMLs. Second, the study population was composed of hospital-based patients and appeared to have more vascular risk factors than community-based cohorts, which would restrict the generalization of our results.

In summary, we demonstrated that serum apoA-I levels were inversely associated with the presence of WMLs in middle-aged and elderly subjects. This association was observed only in women. Apart from HDL cholesterol, traditional serum lipid levels were not independently associated with WMLs. Although further longitudinal studies are needed to confirm the conclusions and to elucidate the mechanisms for the association, our results suggest that therapies which increase apoA-I concentration may be beneficial to reduce the risk of WMLs, dementia and stroke.

Author Contributions

Conceived and designed the experiments: HDZ ZGY LL. Performed the experiments: ZGY MC SMZ MMY. Analyzed the data: ZGY LL. Wrote the paper: ZGY LL MC SMZ MMY HDZ.

References

  1. 1. Debette S, Markus HS (2010) The clinical importance of white matter hyperintensities on brain magnetic resonance imaging: systematic review and meta-analysis. BMJ 341: c3666.
  2. 2. Poggesi A, Pantoni L, Inzitari D, Fazekas F, Ferro J, et al. (2011) 2001–2011: A Decade of the LADIS (Leukoaraiosis And DISability) Study: What Have We Learned about White Matter Changes and Small-Vessel Disease? Cerebrovasc Dis 32: 577–588.
  3. 3. Farrall AJ, Wardlaw JM (2009) Blood-brain barrier: ageing and microvascular disease—systematic review and meta-analysis. Neurobiol Aging 30: 337–352.
  4. 4. Gouw AA, Seewann A, van der Flier WM, Barkhof F, Rozemuller AM, et al. (2011) Heterogeneity of small vessel disease: a systematic review of MRI and histopathology correlations. J Neurol Neurosurg Psychiatry 82: 126–135.
  5. 5. Jickling G, Salam A, Mohammad A, Hussain MS, Scozzafava J, et al. (2009) Circulating endothelial progenitor cells and age-related white matter changes. Stroke 40: 3191–3196.
  6. 6. Crisby M, Bronge L, Wahlund LO (2010) Low levels of high density lipoprotein increase the severity of cerebral white matter changes: implications for prevention and treatment of cerebrovascular diseases. Curr Alzheimer Res 7: 534–539.
  7. 7. Choi HS, Cho YM, Kang JH, Shin CS, Park KS, et al. (2009) Cerebral white matter hyperintensity is mainly associated with hypertension among the components of metabolic syndrome in Koreans. Clin Endocrinol (Oxf) 71: 184–188.
  8. 8. Kuo HK, Chen CY, Liu HM, Yen CJ, Chang KJ, et al. (2010) Metabolic risks, white matter hyperintensities, and arterial stiffness in high-functioning healthy adults. Int J Cardiol 143: 184–191.
  9. 9. Marcovina S, Packard CJ (2006) Measurement and meaning of apolipoprotein AI and apolipoprotein B plasma levels. J Intern Med 259: 437–446.
  10. 10. Zhu X, Parks JS (2012) New roles of HDL in inflammation and hematopoiesis. Annu Rev Nutr 32: 161–182.
  11. 11. Park JH, Hong KS, Lee J, Kim YJ, Song P (2013) Deep subcortical infarct burden in relation to apolipoprotein B/AI ratio in patients with intracranial atherosclerotic stenosis. Eur J Neurol 20: 671–680.
  12. 12. Pantoni L (2010) Cerebral small vessel disease: from pathogenesis and clinical characteristics to therapeutic challenges. Lancet Neurol 9: 689–701.
  13. 13. Saczynski JS, White L, Peila RL, Rodriguez BL, Launer LJ (2007) The relation between apolipoprotein A-I and dementia: the Honolulu-Asia aging study. Am J Epidemiol 165: 985–992.
  14. 14. Fazekas F, Chawluk JB, Alavi A, Hurtig HI, Zimmerman RA (1987) MR signal abnormalities at 1.5 T in Alzheimer's dementia and normal aging. AJR Am J Roentgenol 149: 351–356.
  15. 15. Pantoni L, Basile AM, Pracucci G, Asplund K, Bogousslavsky J, et al. (2005) Impact of age-related cerebral white matter changes on the transition to disability — the LADIS study: rationale, design and methodology. Neuroepidemiology 24: 51–62.
  16. 16. Merched A, Xia Y, Visvikis S, Serot JM, Siest G (2000) Decreased high-density lipoprotein cholesterol and serum apolipoprotein AI concentrations are highly correlated with the severity of Alzheimer's disease. Neurobiol Aging 21: 27–30.
  17. 17. Tirschwell DL, Smith NL, Heckbert SR, Lemaitre RN, Longstreth WT, et al. (2004) Association of cholesterol with stroke risk varies in stroke subtypes and patient subgroups. Neurology 63: 1868–1875.
  18. 18. Amarenco P, Labreuche J, Touboul PJ (2008) High-density lipoprotein-cholesterol and risk of stroke and carotid atherosclerosis: a systematic review. Atherosclerosis 196: 489–496.
  19. 19. Alvarez-Sabin J, Huertas R, Quintana M, Rubiera M, Delgado P, et al. (2007) Prior statin use may be associated with improved stroke outcome after tissue plasminogen activator. Stroke 38: 1076–1078.
  20. 20. Amarenco P, Labreuche J (2009) Lipid management in the prevention of stroke: review and updated meta-analysis of statins for stroke prevention. Lancet Neurol 8: 453–463.
  21. 21. Park K, Yasuda N, Toyonaga S, Yamada SM, Nakabayashi H, et al. (2007) Significant association between leukoaraiosis and metabolic syndrome in healthy subjects. Neurology 69: 974–978.
  22. 22. Breteler MM, van Swieten JC, Bots ML, Grobbee DE, Claus JJ, et al. (1994) Cerebral white matter lesions, vascular risk factors, and cognitive function in a population-based study: the Rotterdam Study. Neurology 44: 1246–1252.
  23. 23. Murray AD, Staff RT, Shenkin SD, Deary IJ, Starr JM, et al. (2005) Brain white matter hyperintensities: relative importance of vascular risk factors in nondemented elderly people. Radiology 237: 251–257.
  24. 24. Jimenez-Conde J, Biffi A, Rahman R, Kanakis A, Butler C, et al. (2010) Hyperlipidemia and reduced white matter hyperintensity volume in patients with ischemic stroke. Stroke 41: 437–442.
  25. 25. Sniderman AD, Furberg CD, Keech A, Roeters van Lennep JE, Frohlich J, et al. (2003) Apolipoproteins versus lipids as indices of coronary risk and as targets for statin treatment. Lancet 361: 777–780.
  26. 26. Holme I, Aastveit AH, Hammar N, Jungner I, Walldius G (2009) Relationships between lipoprotein components and risk of ischaemic and haemorrhagic stroke in the Apolipoprotein MOrtality RISk study (AMORIS). J Intern Med 265: 275–287.
  27. 27. Schmidt R, Fazekas F, Hayn M, Schmidt H, Kapeller P, et al. (1997) Risk factors for microangiopathy-related cerebral damage in the Austrian stroke prevention study. J Neurol Sci 152: 15–21.
  28. 28. Tang C, Liu Y, Kessler PS, Vaughan AM, Oram JF (2009) The macrophage cholesterol exporter ABCA1 functions as an anti-inflammatory receptor. J Biol Chem 284: 32336–32343.
  29. 29. Markus HS, Hunt B, Palmer K, Enzinger C, Schmidt H, et al. (2005) Markers of endothelial and hemostatic activation and progression of cerebral white matter hyperintensities: longitudinal results of the Austrian Stroke Prevention Study. Stroke 36: 1410–1414.
  30. 30. van Dijk EJ, Prins ND, Vermeer SE, Vrooman HA, Hofman A, et al. (2005) C-reactive protein and cerebral small-vessel disease: the Rotterdam Scan Study. Circulation 112: 900–905.
  31. 31. Fornage M, Chiang YA, O'Meara ES, Psaty BM, Reiner AP, et al. (2008) Biomarkers of Inflammation and MRI-Defined Small Vessel Disease of the Brain: The Cardiovascular Health Study. Stroke 39: 1952–1959.
  32. 32. Jalal FY, Yang Y, Thompson J, Lopez AC, Rosenberg GA (2012) Myelin loss associated with neuroinflammation in hypertensive rats. Stroke 43: 1115–1122.
  33. 33. Paula-Lima AC, Tricerri MA, Brito-Moreira J, Bomfim TR, Oliveira FF, et al. (2009) Human apolipoprotein A-I binds amyloid-beta and prevents Abeta-induced neurotoxicity. Int J Biochem Cell Biol 41: 1361–1370.
  34. 34. Lefterov I, Fitz NF, Cronican AA, Fogg A, Lefterov P, et al. (2010) Apolipoprotein A-I deficiency increases cerebral amyloid angiopathy and cognitive deficits in APP/PS1DeltaE9 mice. J Biol Chem 285: 36945–36957.
  35. 35. Gurol ME, Viswanathan A, Gidicsin C, Hedden T, Martinez-Ramirez S, et al. (2012) Cerebral amyloid angiopathy burden associated with leukoaraiosis: A positron emission tomography/magnetic resonance imaging study. Ann Neurol 73: 529–36.
  36. 36. Chao LL, Decarli C, Kriger S, Truran D, Zhang Y, et al. (2013) Associations between white matter hyperintensities and beta amyloid on integrity of projection, association, and limbic fiber tracts measured with diffusion tensor MRI. PLoS One 8: e65175.
  37. 37. Navab M, Reddy ST, Van Lenten BJ, Fogelman AM (2011) HDL and cardiovascular disease: atherogenic and atheroprotective mechanisms. Nature reviews Cardiology 8: 222–232.
  38. 38. Romero JR, Beiser A, Seshadri S, Benjamin EJ, Polak JF, et al. (2009) Carotid artery atherosclerosis, MRI indices of brain ischemia, aging, and cognitive impairment: the Framingham study. Stroke 40: 1590–1596.
  39. 39. Brisset M, Boutouyrie P, Pico F, Zhu Y, Zureik M, et al. (2013) Large-vessel correlates of cerebral small-vessel disease. Neurology 80: 662–669.
  40. 40. Reynolds CA, Gatz M, Prince JA, Berg S, Pedersen NL (2010) Serum lipid levels and cognitive change in late life. J Am Geriatr Soc 58: 501–509.