The role of APOE-ɛ4 and beta amyloid in the differential rate of recovery from ECT: a review

Abstract

Individual biological differences may contribute to the variability of outcomes, including cognitive effects, observed following electroconvulsive treatment (ECT). A narrative review of the research literature on carriage of the apolipoprotein E ɛ4 allele (APOE-ɛ4) and the protein biomarker beta amyloid (Aβ) with ECT cognitive outcome was undertaken. ECT induces repeated brain seizures and there is debate as to whether this causes brain injury and long-term cognitive disruption. The majority of ECT is administered to the elderly (over age 65 years) with drug-resistant depression. Depression in the elderly may be a symptom of the prodromal stage of Alzheimer's disease (AD). Carriage of the APOE-ɛ4 allele and raised cerebral Aβ are consistently implicated in AD, but inconsistently implicated in brain injury (and related syndromes) recovery rates. A paucity of brain-related recovery, genetic and biomarker research in ECT responses in the elderly was found: three studies have examined the effect of APOE-ɛ4 allele carriage on cognition in the depressed elderly receiving ECT, and two have examined Aβ changes after ECT, with contradictory findings. Cognitive changes in all studies of ECT effects were measured by a variety of psychological tests, making comparisons of such changes between studies problematic. Further, psychological test data-validity measures were not routinely administered, counter to current testing recommendations. The methodological issues of the currently available literature as well as the need for well-designed, hypothesis driven, longitudinal studies are discussed.

Biomarkers for Early Diagnostic of Mild Cognitive Impairment in Type-2 Diabetes Patients: A Multicentre, Retrospective, Nested Case–Control Study

“…Secondly, we find that expression of ApoE ε4 gene is strongly associated with the cognitive impairment in T2DM patients. ApoE gene has three major alleles (ɛ2, ɛ3 and ɛ4) based on the amino-acid substitutions (Arg or Cys) at 112 and 158 of the protein ( Sutton et al, 2015 ), in which the ApoE ɛ4 allele has a reduced ability to repair neuronal damage and a decreased antioxidant activity compared with the ɛ2 and ɛ3 ( Ma et al, 1994 ). Growing genetic evidence suggests that ApoE ɛ4 allele is the major genetic risk factor for AD ( Bertram et al, 2010 ) and is associated with an increased risk of MCI conversion into AD ( Devanand et al, 2005 ).…”

Brain Stimulation in Alzheimer's Disease

“…Moreover, a meta-analysis revealed that ECT may increase BDNF levels in depressed patients ( 67 ). Studies have investigated APOE-ε4 and beta amyloid level after ECT treatment, but the findings are contradictory ( 68 ). Moreover, in a trial of ECT for depression, gray matter, and hippocampus volume were reported to increase following ECT ( 69 ).…”