DNA methylation in repetitive elements and Alzheimer disease.

Epigenetics is believed to play a role in Alzheimer's disease (AD). DNA methylation, the most investigated epigenetic hallmark, is a reversible mechanism that modifies genome function and chromosomal stability through the addition of methyl groups to cytosine located in CpG dinucleotides to form 5 methylcytosine (5mC). Methylation status of repetitive elements (i.e. Alu, LINE-1 and SAT-α) is a major contributor of global DNA methylation patterns and has been investigated in relation to a variety of human diseases. However, the role of methylation of repetitive elements in blood of AD patients has never been investigated so far. In the present study, a quantitative bisulfite-PCR pyrosequencing method was used to evaluate methylation of Alu, LINE-1 and SAT-α sequences in 43 AD patients and 38 healthy donors. In multivariate analysis adjusting for age and gender, LINE-1 was increased in AD patients compared with healthy volunteers (ADs: 83.6%5mC, volunteers: 83.1%5mC, p-value: 0.05). The group with best performances in mini mental state examination (MMSE) showed higher levels of LINE-1 methylation compared to the group with worst performances (MMSE>22: 83.9%5mC; MMSE≤22: 83.2%5mC; p=0.05). Our data suggest that LINE-1 methylation may lead to a better understanding of AD pathogenesis and course, and may contribute to identify novel markers useful to assess risk stratification. Further prospective investigations are warranted to evaluate the dynamics of DNA methylation from early-stage AD to advanced phases of the disease.

Novel exon 1 progranulin gene variant in Alzheimer's disease.

BACKGROUND AND PURPOSE: Progranulin (PGRN) expression is increased in activated microglia in Alzheimer's disease (AD) brain, suggesting a potential role in this pathology. METHODS: A mutation scanning of exons and flanking regions of PGRN was carried out in 120 patients with sporadic frontotemporal lobar degeneration and 145 with sporadic AD. RESULTS: Amongst variants not yet deposited, a novel allelic variant was identified in Exon 1 (g100169G > A). It leads to an amino acidic change (p.Gly35Arg) and was observed in a patient with late onset AD. In silico analysis predicted that this mutation is possibly damaging. A second variant (g.100165C > T), resulting in a silent mutation (pAsp33Asp), was found in a patient with semantic dementia and in another with early onset AD. Both variants were absent in 226 controls. In addition, two rare non-pathogenic variants lying very close to PGRN splice-site regions (IVS2 + 7-->G > A and IVS7 + 7-->G > A) were observed. Transcriptional analysis in peripheral blood mononuclear cells from patients demonstrated they do not affect exon splicing. CONCLUSIONS: A novel putative PGRN mutation leading to an amino acidic substitution was identified in a patient with clinical AD.

Atorvastatin increases HDL cholesterol in hypercholesterolemic patients. Evidence of a relationship with baseline HDL cholesterol.

BACKGROUND AND AIM: It has been reported that atorvastatin increases high-density lipoprotein cholesterol (HDL-C) more in patients with low than in those with high baseline HDL-C levels. This may have a biological explanation, but also suggests a statistical artifact known as the regression to the mean. METHODS AND RESULTS: Atorvastatin 10 mg/day led to a 4% increase in HDL-C after two months in 67/121 patients with hypercholesterolemia (55%), who had lower baseline HDL-C levels than the patients in whom HDL-C did not increase. In the patients with baseline HDL-C below the median, HDL-C significantly increased whereas no change was observed in patients with baseline HDL-C above the median. The correlation coefficient between pre- and post-treatment HDL-C was 0.84, thus suggesting a regression to the mean. However, the regression artifact did not entirely explain the increase in HDL-C in patients with low baseline HDL-C or the lack of an increase in those with high baseline HDL-C. The adjusted mean increase was 5.4% in patients with low pretreatment HDL-C, and 2.4% in the patients with high pretreatment HDL-C. Multiple regression analysis with the changes in HDL-C as the dependent variable showed that baseline HDL-C and the changes in serum triglycerides independently contributed to the change in HDL-C levels. CONCLUSIONS: Atorvastatin 10 mg/day increases HDL-C more in patients with low pretreatment HDL-C levels, an effect that seems to be related to the hypotriglyceridemic activity of the drug.

Effects of low doses of simvastatin and atorvastatin on high-density lipoprotein cholesterol levels in patients with hypercholesterolemia.

BACKGROUND: Simvastatin 40 to 80 mg/d has been found to increase high-density lipoprotein cholesterol (HDL-C) levels significantly more than atorvastatin at equipotent doses (ie, 20-80 mg/d). Data on the effects of lower doses of the 2 drugs on HDL-C levels are conflicting. OBJECTIVE: The purpose of this study was to investigate the effects of simvastatin 20 mg/d and atorvastatin 10 mg/d on HDL-C levels in patients with hypercholesterolemia. METHODS: Patients with primary hypercholesterolemia (total cholesterol [TC] >250 mg/dL) who were not taking any lipid-lowering agents and who were following a low-fat diet were randomized to receive 1 of 2 treatments: simvastatin 20 mg/d or atorvastatin 10 mg/d. Serum TC, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and HDL-C levels were measured using standard methods after 2 months of therapy. In a secondary analysis, lipids and lipoprotein cholesterol were measured after 1 year in patients who continued treatment. RESULTS: Of the 240 patients enrolled (108 men and 132 women; age range, 23-77 years, mean [SEM] 56.7 [0.69]), 235 completed the study. After 2 months of therapy, TC, LDL-C, and serum TG levels decreased significantly versus baseline in both groups (P < 0.001), with no significant differences between treatment groups. HDL-C levels increased by 9.0% (P < 0.001 vs baseline) in the simvastatin group and by 4.3% (P < 0.02) in the atorvastatin group. The difference between the 2 groups in the percentage increase in HDL-C was statistically significant (P < 0.05). In 113 patients who continued treatment, HDL-C levels at 1 year were still significantly higher than baseline levels in the simvastatin group (6.3%, P = 0.034), but not in the atorvastatin group (2.8%, P = 0.587). CONCLUSIONS: The findings from this study suggest that the HDL-C-increasing effect of simvastatin 20 mg is significantly greater than that of atorvastatin 10 mg. Since increasing HDL-C levels is thought to lower the risk for atherosclerosis and coronary heart disease, these results warrant further investigation.