Apolipoprotein E Genotype in Very Preterm Neonates with Intrauterine Growth Restriction: An Analysis of the German Neonatal Network Cohort

Apolipoprotein E polymorphisms and female fertility in a transgenic mouse model of Alzheimer's disease

Apolipoprotein E (APOE) is a major cholesterol carrier responsible for lipid transport and injury repair in the brain. The human APOE gene (h-APOE) has 3 naturally occurring alleles: ε3, the common allele; ε4, which increases Alzheimer's disease (AD) risk up to 15-fold; and ε2, the rare allele which protects against AD. Although APOE4 has negative effects on neurocognition in old age, its persistence in the population suggests a survival advantage. We investigated the relationship between APOE genotypes and fertility in EFAD mice, a transgenic mouse model expressing h-APOE. We show that APOE4 transgenic mice had the highest level of reproductive performance, followed by APOE3 and APOE2. Intriguingly, APOE3 pregnancies had more fetal resorptions and reduced fetal weights relative to APOE4 pregnancies. In conclusion, APOE genotypes impact fertility and pregnancy outcomes in female mice, in concordance with findings in human populations. These mouse models may help elucidate how h-APOE4 promotes reproductive fitness at the cost of AD in later life.

Apolipoprotein E and Atherosclerosis

PURPOSE OF REVIEW

The functions, genetic variations and impact of apolipoprotein E on lipoprotein metabolism in general are placed in the context of clinical practice dealing with moderate dyslipidaemia as well as dysbetalipoproteinemia, a highly atherogenic disorder and lipoprotein glomerulopathy.

RECENT FINDINGS

Additional variants of apolipoprotein E and participation of apolipoprotein E in inflammation are of interest. The mostly favourable effects of apolipoprotein E2 as well as the atherogenic nature of apolipoproteinE4, which has an association with cognitive impairment, are confirmed. The contribution of remnant lipoproteins of triglyceride-rich lipoproteins, of which dysbetalipoproteinemia represents an extreme, is explored in atherosclerosis. Mimetic peptides may present new therapeutic approaches. Apolipoprotein E is an important determinant of the lipid profile and cardiovascular health in the population at large and can precipitate dysbetalipoproteinemia and glomerulopathy. Awareness of apolipoprotein E polymorphisms should improve medical care.

Apolipoprotein-E Gene Polymorphism and Lipid Composition among IUGR and AGA Neonates

Objective The objective of this study is to study the profile of apolipoprotein E (APOE) gene polymorphism and lipid profile among intrauterine growth restriction (IUGR) and appropriate for gestational age (AGA) neonates. This is an observational study. This study was done at the neonatal unit of a teaching hospital in South India. All consecutively born IUGR neonates (cases) of more than 32 weeks' gestational age and AGA neonates (controls) were enrolled for the study. Genomic DNA extraction was done from a total of 102 peripheral venous blood samples. Genotyping of the APOE rs429358 and rs7412 defining the ε2, ε3, and ε4 alleles was done by polymerase chain reaction–restriction fragment length polymorphism method. Prefeed venous blood was collected and analyzed for lipid profile estimation. The allelic frequencies of cases versus control were ε2—9 (8.7%) versus 3 (2.9%); ε3—88 (84.6%) versus 81 (79.4%); and ε4–7 (6.7%) versus 18 (17.6%). The frequency of ε4 isoform allele, associated with adult onset of metabolic diseases was less among the IUGR group. The mean total cholesterol (TC), Low-Density Lipoprotein (LDL), High-Density Lipoprotein, and triglyceride (TG) were 107.59 ± 35.99, 51.69 ± 24.68, 21.75 ± 9.58, and 151.22 ± 61.84 mg/dL, respectively, in the IUGR group. The mean TC and LDL levels in IUGR group were marginally higher than AGA neonates (107 ± 35.99 vs. 100.37 ± 22.69 mg/dL and 51.69 ± 24.68 versus 46.9 ± 19.51 mg/dL, p > 0.05). In both groups, the mean TC and TGL levels were elevated in the ε4 isoform subgroup (p > 0.05). In our study, the ε2 allele was the second most predominant APOE isoform and the ε4 allele of the APOE gene associated with adult-onset diseases was not increased among IUGR neonates. Neonates with ε4 allele showed an abnormal lipid profile in both study groups suggesting a possible association.

Impact of Apolipoprotein E gene polymorphism during normal and pathological conditions of the brain across the lifespan

The central nervous system (CNS) is the cellular substrate for the integration of complex, dynamic, constant, and simultaneous interactions among endogenous and exogenous stimuli across the entire human lifespan. Numerous studies on aging-related brain diseases show that some genes identified as risk factors for some of the most common neurodegenerative diseases - such as the allele 4 of APOE gene (APOE4) for Alzheimer's disease (AD) - have a much earlier neuro-anatomical and neuro-physiological impact. The impact of APOE polymorphism appears in fact to start as early as youth and early-adult life. Intriguingly, though, those same genes associated with aging-related brain diseases seem to influence different aspects of the brain functioning much earlier actually, that is, even from the neonatal periods and earlier. The APOE4, an allele classically associated with later-life neurodegenerative disorders as AD, seems in fact to exert a series of very early effects on phenomena of neuroplasticity and synaptogenesis that begin from the earliest periods of life such as the fetal ones.We reviewed some of the findings supporting the hypothesis that APOE polymorphism is an early modifier of various neurobiological aspects across the entire human lifespan - from the in-utero to the centenarian life - during both normal and pathological conditions of the brain.