The screening of Alzheimer’s patients with CSF biomarkers,modulates the distribution of APOE genotype: impact on clinical trials

Polymorphism of the apolipoprotein E gene (APOE) plays a role in the level of neuropathological lesions and in drug response in Alzheimer’s disease (AD). The aim of this study was to investigate whether the selection of AD patients based on cerebrospinal fluid (CSF) biomarkers assessment may be biased by their APOE distribution. We studied the relationships between APOE genotype and CSF biomarkers levels in a total of 432 patients (AD, n = 244; non-AD, n = 188) explored for cognitive disorders. We studied the distribution of APOE genotypes among AD patient subgroups selected by various cut-offs of CSF biomarkers. Strategies of screening based on CSF Aβ1–42 lead to overselection of ε4/ε4 patients in the AD group. Screening based on tau levels did not change Apoe4 distribution in the AD group. CSF Aβ1–42 discriminated better AD patients with at least one ε4 than AD patients with no ε4. A strong allele-effect relationship was detected between APOE genotype and CSF amyloid-β (Aβ1–42) in AD patients. Selecting AD patients on CSF amyloid levels only may create an overselection of ε4/ε4 carriers, and might potentially bias the population of patients included in clinical trial studies.     

Mid-term echographic evaluation of systolic function after cardiac transplantation

The aim of this study was to analyse variations in left ventricular mass (LVM) and systolic function after cardiac transplantation and to evaluate eventual changes induced by the onset of systemic hypertension (HT). In a retrospective study, we selected the echocardiographic examinations of 42 patients performed at the end of the first month (M1), sixth month (M6), and at the end of follow-up (ME) after cardiac transplantation. The patients were divided into two groups (NT: n = 14; HT: n = 28) depending on whether hypertension occurred during follow-up. The average duration of follow-up was 12.8 +/- 6 months; this was comparable in the two groups. Mild left ventricular hypertrophy was observed from the first postoperative examination: M1 = 193 +/- 50 g; M6 = 199 +/- 62 g; ME = 197 +/- 45 g (NS). The hypertrophy was constant with time and related to wall thickening; it was associated with an increased left ventricular fractional shortening (FS) which decreased with time especially in the NT group (average/42 patients: M1 = 0.38 +/- 0.09; M6 = 0.34 +/- 0.08; ME = 0.35 +/- 0.05; p = 0.03 between M1 and ME). The influence of hypertension on the development of LVH and wall thickening was negligible. The role of transplant rejection should be considered: the repetition of episodes of rejection was less marked than the histological severity of rejection. The role of other factors (ischaemia, persistent haemodynamic abnormalities) is a matter of discussion.