APOE and vascular disease: Sequencing and genotyping in general population cohorts

The ε4 allele plays a role in vascular dementia.

“ε4 also plays a role in vascular dementia [21][22][23][24][25][26]”

• cites [21] Rasmussen, 2018, Absolute 10-year risk of dementia by age, sex and APOE genotype: a population-based cohort study, CMAJ (Can. Med. Assoc. J.) sourceSupported
• cites [22] Mou, 2015, Correlation of polymorphism of APOE and LRP genes to cognitive impairment and behavioral and psychological symptoms of dementia in Alzheimer's disease and vascular dementia, Int. J. Clin. Exp. Med.Not checked — no full text of the source
• cites [23] Baum, 2006, Apolipoprotein E epsilon4 allele is associated with vascular dementia, Dement. Geriatr. Cogn. Disord sourceNot checked — no full text of the source
• cites [24] Chuang, 2010, Association between APOE epsilon4 allele and vascular dementia: the Cache County study, Dement. Geriatr. Cogn. Disord sourceSupported
• cites [25] Liu, 2012, ApoE gene polymorphism and vascular dementia in Chinese population: a meta-analysis, J. Neural. Transm. sourceNot checked — no full text of the source
• cites [26] Yin, 2012, Association between apolipoprotein E gene polymorphism and the risk of vascular dementia: a meta-analysis, Neurosci. Lett. sourceNot checked — no full text of the source

The risk increase for PAD in ε22 genotype was also recently reported cross-sectionally in the UK Biobank.

“a risk increase also recently reported cross-sectionally in the UK Biobank [42]”

• cites [42] Lumsden, 2020, genotype-associated disease risks: a phenome-wide, registry-based, case-control study utilising the UK Biobank, EBioMedicine sourceSupported

The ε4 allele is associated with an atherogenic lipid profile with a moderate increase in both plasma LDL cholesterol and triglycerides for ε44 versus the ε33 genotype.

“the ε4 allele is associated with an atherogenic lipid profile with a moderate increase in both plasma LDL cholesterol and triglycerides for ε44 versus the ε33 genotype [8].”

• cites [8] Rasmussen, 2019, Plasma levels of apolipoprotein E, APOE genotype, and all-cause and cause-specific mortality in 105 949 individuals from a white general population cohort, Eur. Heart J. sourceSupported

For more clear-cut atherosclerotic manifestations as IHD and PAD, plasma levels of apoE are not the causal factor but rather reflects levels of atherogenic lipoproteins.

“For more clear-cut atherosclerotic manifestations as IHD and PAD, plasma levels of apoE are not the causal factor but rather reflects levels of atherogenic lipoproteins [8].”

• cites [8] Rasmussen, 2019, Plasma levels of apolipoprotein E, APOE genotype, and all-cause and cause-specific mortality in 105 949 individuals from a white general population cohort, Eur. Heart J. sourcePartly supported

  The Discussion (page not available in our copy) says high plasma apoE correlates with atherogenic triglyceride-rich lipoproteins and that genetic estimates did not indicate a causal association with cardiovascular mortality. It discusses ischaemic heart disease risk, but does not establish the same noncausal conclusion for IHD or PAD specifically; its causal analysis concerns mortality, not those disease outcomes. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

The similar findings for rare APOE variants with low apoE may reflect that the intracerebral vasculature, brain tissue and blood-brain barrier are dependent on normal levels of apoE for sufficient local lipid transport and β-amyloid clearance.

“The similar findings presently observed for rare APOE variants with low apoE may reflect that the intracerebral vasculature, brain tissue and blood-brain barrier are dependent on normal levels of apoE for sufficient local lipid transport and βamyloid clearance [17,18,31,43].”

• cites [17] Bell, 2012, Apolipoprotein E controls cerebrovascular integrity via cyclophilin A, Nature sourcePartly supported

  The paper reports that Apoe-deficient mice develop blood–brain barrier breakdown, microvascular defects and later neuronal changes (Abstract; page not provided). This supports a role for apoE in cerebrovascular integrity, but the cited passages do not establish that rare low-apoE variants impair local lipid transport or β-amyloid clearance. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [18] Cramer, 2012, ApoE-directed therapeutics rapidly clear beta-amyloid and reverse deficits in AD mouse models, Science sourcePartly supported

  The paper's main text (indexed under Abstract; page unavailable) links apoE and lipid transport to soluble β-amyloid clearance, and reports that enhanced clearance in mice required apoE. It does not establish that intracerebral vasculature or the blood-brain barrier depend on normal apoE levels, or test the rare APOE variants in the citing sentence. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [31] Zlokovic, 2011, Neurovascular pathways to neurodegeneration in Alzheimer's disease and other disorders, Nat. Rev. Neurosci. sourcePartly supported

  The Alzheimer’s disease section (page not available) describes amyloid-β clearance across the blood–brain barrier and says APOE4, unlike APOE3 or APOE2, impedes LRP1-mediated clearance. It does not establish that rare variants producing low apoE impair clearance, or that normal apoE levels are required for local lipid transport in the vasculature and brain tissue. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [43] Mawuenyega, 2010, Decreased clearance of CNS beta-amyloid in Alzheimer's disease, Science sourcePartly supported

  The passage labeled Abstract (page not provided) reports reduced CNS β-amyloid clearance in Alzheimer’s disease and lists ApoE4 interactions and impaired blood-brain-barrier transport as possible mechanisms. It does not examine rare APOE variants with low apoE or establish that normal apoE levels are needed for local lipid transport in brain tissue and vasculature. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

The disease spectrum comprising Alzheimer disease, vascular dementia, and cerebrovascular disease is likely linked by deposition of amyloid-β in arterioles in the central nervous system combined with degradation of the blood-brain barrier, which collectively leaves a frail intracerebral vasculature prone to atherosclerotic cerebrovascular disease.

“Together this comprises a disease spectrum likely linked by deposition of amyloid-β in arterioles in the central nervous system combined with degradation of the blood-brain barrier, which collectively leaves a frail intracerebral vasculature prone to atherosclerotic cerebrovascular disease [17,31,32].”

• cites [17] Bell, 2012, Apolipoprotein E controls cerebrovascular integrity via cyclophilin A, Nature sourcePartly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites [31] Zlokovic, 2011, Neurovascular pathways to neurodegeneration in Alzheimer's disease and other disorders, Nat. Rev. Neurosci. sourcePartly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites [32] Verghese, 2011, In Alzheimer's disease and other neurological disorders, Lancet Neurol. sourcePartly supported

  The section on APOE and cerebral amyloid angiopathy (page unavailable) describes amyloid-β deposition in CNS arterioles and notes that CAA co-occurs with Alzheimer disease. The vascular dementia section (page unavailable) discusses a possible contribution from concomitant Alzheimer pathology, but the paper does not establish the claimed disease spectrum or describe blood-brain barrier degradation combined with amyloid deposition as leaving vessels prone to atherosclerotic cerebrovascular disease. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

The associations with plasma apoE and risk of ICVD for rare APOE variants were similar to those observed for ε44 homozygotes.

“These associations with plasma apoE and risk of ICVD were similar to those observed for ɛ44 homozygotes.”

58-67% of ε22 homozygotes in age groups 20-29 to 80+ years had remnant cholesterol levels above the age-and sex adjusted population median, in contrast to ε33.

“Fifty-eight to 67% of ɛ22 homozygotes in age groups 20-29 to 80+ years had remnant cholesterol levels above the age-and sex adjusted population median, in contrast to ɛ33 (Figure 2).”

Some rare APOE variants with trends towards lower plasma apoE were associated with increased risk of ICVD.

“We observed that some rare APOE variants with trends towards lower plasma apoE were associated with increased risk of ICVD.”

A total of 27 rare variants were identified by sequencing the coding exons (exons 2-4) of APOE in 10,296 individuals in the CCHS.

“A total of 27 rare variants were identified by sequencing the coding exons (exons 2-4) of APOE in 10,296 individuals in the CCHS (Supplementary Figure 1).”

For the six common APOE ε2/ε3/ε4 genotypes, LDL cholesterol and apolipoprotein B increased from ε22 to ε32 to ε42 to ε33 to ε43 to ε44.

“For the six common APOE ε2/ε3/ε4 genotypes LDL cholesterol and apolipoprotein B increased (p for trends<1x10 -300 ) and plasma apoE, HDL cholesterol and apolipoprotein A1 decreased (p for trends≤4x10 -76 ) from ε22 to ε32 to ε42 to ε33 to ε43 to ε44”

For the LDL cholesterol weighted allele score in three groups, plasma apoE, HDL cholesterol and apoA1 decreased per LDL increasing weighted allele score group.

“For the LDL cholesterol weighted allele score in three groups plasma apoE, HDL cholesterol and apoA1 decreased (p for trends≤8x10 -73 )”

For 80+ year old individuals, corresponding percentages for ε44 homozygotes were 44 and 45%.

“For the 80+ year old individuals corresponding percentages for ε44 homozygotes were 44 and 45%.”

For the six common APOE ε2/ε3/ε4 genotypes, plasma apoE, HDL cholesterol and apolipoprotein A1 decreased from ε22 to ε32 to ε42 to ε33 to ε43 to ε44.

“For the six common APOE ε2/ε3/ε4 genotypes LDL cholesterol and apolipoprotein B increased (p for trends<1x10 -300 ) and plasma apoE, HDL cholesterol and apolipoprotein A1 decreased (p for trends≤4x10 -76 ) from ε22 to ε32 to ε42 to ε33 to ε43 to ε44”

For individuals with low LDL cholesterol (negative weighted allele score) and high plasma apoE and remnant cholesterol, the risk for PAD was increased.

“A multifactorially and ɛ2/ɛ3/ɛ4 adjusted hazard ratio for the LDL cholesterol weighted allele score on the continuous scale in a restricted cubic spline curve showed that for individuals with low LDL cholesterol (negative weighted allele score) and high plasma apoE and remnant cholesterol the risk for PAD was increased (Figure 5).”

The trends for risk of vascular disease across APOE genotypes did not remain after adjustment for lipids, lipoproteins and apolipoproteins (p for trends=0.98 in CCHS+CGPS and =0.06 in UK Biobank).

“and these trends did not remain after adjustment for lipids, lipoproteins and apolipoproteins (p for trends=0.98 in the CCHS+CGPS and =0.06 in the UK Biobank) (Figure 4).”

For triglyceride levels, 58-66% of ε22 homozygotes in age groups 20-29 to 80+ years had levels above the age-and sex adjusted population median.

“For triglyceride levels similar percentages were 58-66% (Figure 2).”

Remnant cholesterol and triglycerides were lowest for the reference group (ε33).

“Remnant cholesterol and triglycerides were lowest for the reference group (ε33) (p≤4x10 - 59 ) (Figure 1).”

Nine of the nonsynonymous rare variants had a MAF ≥0.01%.

“Nine of the nonsynonymous rare variants had a MAF ≥0.01%.”

For the LDL cholesterol weighted allele score in three groups, LDL cholesterol and apoB increased per LDL increasing weighted allele score group.

“whereas LDL cholesterol and apoB increased per LDL increasing J o u r n a l P r e -p r o o f weighted allele score group (p for trends<1x10 -300 )”

Multifactorially adjusted hazard ratios for individual rare variants were largely unchanged after further adjustment for lipids, lipoproteins and apolipoproteins and further for APOE ε2/ε3/ε4.

“Multifactorially adjusted hazard ratios for individual rare variants are shown in Supplementary Figure 3, and were largely J o u r n a l P r e -p r o o f unchanged after further adjustment for lipids, lipoproteins and apolipoproteins (Supplementary Figure 4) and further for APOE ε2/ε3/ε4 (Supplementary Figure 5).”

The nine rare variants together with the two common variants, ε2 (Arg176Cys) and ε4 (Cys130Arg), give in total 11 variants with MAF ≥0.01%.

“These nine rare variants together with the two common variants, ɛ2 (Arg176Cys) and ɛ4 (Cys130Arg), give in total 11 variants with MAF ≥0.01%.”

In the CCHS, 1/257 (40/10,296) individuals in the general population carried a rare variant (MAF≤0.06%) in APOE predicted to be deleterious in silico.

“Of note, in the CCHS 1/257 (40/10,296) individuals in the general population carried a rare variant (MAF≤0.06%) in APOE predicted to be deleterious in silico (Supplementary Table 3).”

We identified Gly145Asp and Arg154Cys in the same region (amino acids ~148 to 168).

“We identified Gly145Asp and Arg154Cys in the same J o u r n a l P r e -p r o o f region (amino acids ~ 148 to 168) [47]”

• cites [47] Weisgraber, 1994, Apolipoprotein E: structure-function relationships, Adv. Protein Chem. sourceNot checked — no full text of the source

Below an age of 80 years, remnant cholesterol and triglycerides were increased for ε44 homozygotes compared to ε33 with 52-61% and 52-68% above the population median, respectively.

“Further, below an age of 80 years remnant cholesterol and triglycerides were increased for ε44 homozygotes compared to ε33 with 52-61% and 52-68% above the population median, respectively (Figure 2).”

For remnant cholesterol and triglycerides, the highest levels were observed in ε22, ε42 and ε44 carriers.

“For remnant cholesterol and triglycerides the highest levels were observed in ε22, ε42 and ε44 carriers (Figure 1 and Supplementary Figure 2).”

Rare mutations in APOE predicted to be deleterious are present in 1 in 257 individuals in the general population.

“Rare mutations in APOE, predicted to be deleterious, are present in 1 in 257 individuals in the general population”

APOE variants associated with high apoE, triglycerides, and remnant cholesterol are associated with PAD.

“APOE variants associated with high apoE, triglycerides, and remnant cholesterol are associated with PAD”

Common APOE variants with high LDL cholesterol, triglycerides and remnant cholesterol are associated with IHD.

“whereas common APOE variants with high LDL cholesterol, triglycerides and remnant cholesterol are associated with IHD.”

APOE variants associated with low apoE are associated with increased risk of ICVD.

“we found that APOE variants associated with low apoE are associated with increased risk of ICVD.”

• Also stated in: § Figure 5 · plain

  “Variants with low apoE are associated with ischemic cerebrovascular disease.”

Similar results were observed in the UK Biobank.

“Similar results were observed in the UK Biobank (Figure3, middle horizontal panel).”

Risk of IHD increased stepwise from ɛ22 to ɛ32 to ɛ42.

“Risk of IHD increased stepwise from ɛ22 to ɛ32 to ɛ42”

At the time of inclusion, 2% of individuals with ε22 genotype without lipid lowering therapy had total cholesterol >7.8 mmol/L (>300 mg/dL) and triglycerides >3.4 mmol/L (>300 mg/dL).

“However, it is interesting that at the time of inclusion in our study, 2% of individuals with ε22 genotype without lipid lowering therapy had a total cholesterol >7.8 mmol/L (>300 mg/dL) and triglycerides>3.4mmol/L (>300 mg/dL).”

ɛ2-like variants are associated with peripheral arterial disease.

“ɛ2-like variants are associated with peripheral arterial disease.”

Individuals with ε22 genotype have increased risk of PAD.

“and that individuals with this genotype have increased risk of PAD”

Variants predicted by models to be deleterious or located near or in the receptor binding region (amino acids ~148 to 168) could be suspected to pose ε2-like qualities.

“Variants predicted by models to be deleterious or being located near or in the receptor binding region (amino acids ~ 148 to 168) [47] could be suspected to pose ε2-like qualities.”

• cites [47] Weisgraber, 1994, Apolipoprotein E: structure-function relationships, Adv. Protein Chem. sourceNot checked — no full text of the source

APOE variants with high apoE, triglycerides, and remnant cholesterol are associated with PAD.

“APOE variants with high apoE, triglycerides, and remnant cholesterol are associated with PAD”

APOE variants with low apoE are associated with increased risk of ICVD.

“whereas APOE variants with low apoE are associated with increased risk of ICVD”

The ε4 allele plays a role in cerebrovascular disease.

“and cerebrovascular disease [21,[27][28][29][30].”

• cites [21,[27][28][29][30]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Rare variants in addition to common variants in APOE both contribute to monogenic and polygenic hyperlipidemias.

“With the present sequencing and genotyping strategy and subsequently observed effects on lipid metabolism, we suggest that rare variants in addition to common variants in APOE both contribute to monogenic and polygenic hyperlipidemias.”

The generalizability of the study may be limited because it studied White individuals only.

“One potential limitation is that the generalizability of our study may be limited because we studied White individuals only.”

A fraction of these rare variants may contribute to susceptibility to dysbetalipoproteinemia or familial hypercholesterolemia (FH).

“This suggests that a fraction of these variants may contribute to susceptibility to dysbetalipoproteinemia or familial hypercholesterolemia (FH).”

• Also stated in: § 4. Discussion · hedged

  “suggesting that a fraction of these variants may contribute to susceptibility to dysbetalipoproteinemia or FH.”

The relative discrete LDL increase observed in ε4 hetero- and homozygotes and in rare APOE mutation carriers are apparently not enough to increase risk of IHD and PAD significantly in the present study.

“The relative discrete LDL increase observed in ɛ4 hetero-and homozygotes and in rare APOE mutation carriers are apparently not enough to increase risk of IHD and PAD significantly in the present study.”

The persistence of findings for ε44 for ICVD and ε22 for PAD after adjustment suggests different etiologies of the three disease entities.

“Interestingly, our findings for ε44 for ICVD and for ε22 for PAD did remain after adjustment for lipids, lipoproteins and apolipoproteins, suggesting different etiologies of the three disease entities.”

Common APOE variants with high LDL cholesterol, remnant cholesterol and triglycerides are associated with IHD.

“common APOE variants with high LDL cholesterol, remnant cholesterol and triglycerides are associated with IHD”

ICVD diagnoses were validated by trained physicians using WHO definitions of cerebrovascular disease.

“Possible cerebrovascular events (hospitalized and non-hospitalized) were validated by trained physicians using the WHO definitions of cerebrovascular disease, as previously described [34].”

• cites [34] Nordestgaard, 2015, Loss-of-function mutation in ABCA1 and risk of Alzheimer's disease and cerebrovascular disease, Alzheimers Dement sourceNot checked — no full text of the source

We now further extend this knowledge to include other rare mutations with similar effects on plasma apoE, lipids, lipoproteins and PAD, as for ε2.

“We now further extend this knowledge to include other rare mutations with similar effects on plasma apoE, lipids, lipoproteins and PAD, as for ɛ2.”

Our results are likely to be applicable to most humans.

“so our results are likely to be applicable to most humans.”

• AssumptionRests on an assumption: The impact of the APOE polymorphism is well described among many ethnicities.

Both rare and common structural variation in APOE play a role in vascular disease.

“These findings highlight that both rare and common structural variation in APOE play a role in vascular disease.”

• Also stated in: § J o u r n a l P r e -p r o o f · plain

  “Both rare and common structural variants in APOE play a role in vascular disease in the general population”

A fraction of these rare APOE variants may contribute to susceptibility to dysbetalipoproteinemia or FH.

“suggesting that a fraction of these variants may contribute to susceptibility to dysbetalipoproteinemia or FH.”

Structural variations in APOE beyond the ɛ2 and ɛ4 alleles play a role.

“Structural variations in APOE beyond the ɛ2 and ɛ4 alleles play a role.”

The number of vascular events for the majority of rare variants is a limitation.

“A fourth limitation is the number of vascular events for the majority of rare variants.”

We added information beyond the estimates for individual rare variants by using a genetic score based on the genetic contribution to LDL cholesterol, the atherogenic lipoprotein trait most strongly affected by APOE variants.

“We did however add information beyond the estimates for individual rare variants by using a genetic score based on the genetic contribution to LDL cholesterol, the atherogenic lipoprotein trait most strongly affected by APOE variants.”

• AssumptionRests on an assumption: LDL cholesterol is the atherogenic lipoprotein trait most strongly affected by APOE variants.