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Meta-analysis of peripheral blood apolipoprotein E levels in Alzheimer's disease.

Wang C, Yu JT, Wang HF, Jiang T, Tan CC, Meng XF, Soares HD, Tan L - PLoS ONE (2014)

Bottom Line: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed.The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]).The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong, China.

ABSTRACT

Background: Peripheral blood Apolipoprotein E (ApoE) levels have been proposed as biomarkers of Alzheimer's disease (AD), but previous studies on levels of ApoE in blood remain inconsistent. This meta-analysis was designed to re-examine the potential role of peripheral ApoE in AD diagnosis and its potential value as a candidate biomarker.

Methods: We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane library, and BIOSIS previews for case-control studies measuring ApoE levels in serum or plasma from AD subjects and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between ApoE levels and AD risk.

Results: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed. The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]). The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

Conclusions: Our meta-analysis supports a lowered level of blood ApoE in AD patients, and indicates its potential value as an important risk factor for AD. Further investigation employing standardized assay for ApoE measurement are still warranted to uncover the precise role of ApoE in the pathophysiology of AD.

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Forest plots for ApoE levels in ε3/ε3 and ε3/ε4 carriers.(a) Forest plots for ApoE levels in ε3/ε3 carriers. (b) Forest plots for ApoE levels in ε3/ε4 carriers. AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.
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pone-0089041-g005: Forest plots for ApoE levels in ε3/ε3 and ε3/ε4 carriers.(a) Forest plots for ApoE levels in ε3/ε3 carriers. (b) Forest plots for ApoE levels in ε3/ε4 carriers. AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.

Mentions: Five studies reported the ApoE concentration for AD patients and normal controls stratified according to the APOE genotypes. Because of lacking sufficient numbers of subjects from included studies, we just performed the analysis in ε3/ε3 and ε3/ε4 separately. In ε3/ε3 carriers, the WMD was negative as well (−3.31 [−6.16, −0.45]; P = 0.01). However, we found no significant association between ApoE and AD among ε3/ε4 carriers (−1.66 [−3.79, 0.47]; P = 0.80). (Figure 5)


Meta-analysis of peripheral blood apolipoprotein E levels in Alzheimer's disease.

Wang C, Yu JT, Wang HF, Jiang T, Tan CC, Meng XF, Soares HD, Tan L - PLoS ONE (2014)

Forest plots for ApoE levels in ε3/ε3 and ε3/ε4 carriers.(a) Forest plots for ApoE levels in ε3/ε3 carriers. (b) Forest plots for ApoE levels in ε3/ε4 carriers. AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928366&req=5

pone-0089041-g005: Forest plots for ApoE levels in ε3/ε3 and ε3/ε4 carriers.(a) Forest plots for ApoE levels in ε3/ε3 carriers. (b) Forest plots for ApoE levels in ε3/ε4 carriers. AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.
Mentions: Five studies reported the ApoE concentration for AD patients and normal controls stratified according to the APOE genotypes. Because of lacking sufficient numbers of subjects from included studies, we just performed the analysis in ε3/ε3 and ε3/ε4 separately. In ε3/ε3 carriers, the WMD was negative as well (−3.31 [−6.16, −0.45]; P = 0.01). However, we found no significant association between ApoE and AD among ε3/ε4 carriers (−1.66 [−3.79, 0.47]; P = 0.80). (Figure 5)

Bottom Line: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed.The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]).The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong, China.

ABSTRACT

Background: Peripheral blood Apolipoprotein E (ApoE) levels have been proposed as biomarkers of Alzheimer's disease (AD), but previous studies on levels of ApoE in blood remain inconsistent. This meta-analysis was designed to re-examine the potential role of peripheral ApoE in AD diagnosis and its potential value as a candidate biomarker.

Methods: We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane library, and BIOSIS previews for case-control studies measuring ApoE levels in serum or plasma from AD subjects and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between ApoE levels and AD risk.

Results: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed. The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]). The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

Conclusions: Our meta-analysis supports a lowered level of blood ApoE in AD patients, and indicates its potential value as an important risk factor for AD. Further investigation employing standardized assay for ApoE measurement are still warranted to uncover the precise role of ApoE in the pathophysiology of AD.

Show MeSH
Related in: MedlinePlus