Age, Sex, Hypertension and HDL-C Alter Serum BACE1 Activity in Cognitively Normal Subjects: Implications for Alzheimer's Disease.

BACKGROUND: Increasing evidence indicates that ß-secretase 1 (BACE1) activity and concentration in blood are candidate biomarkers for Alzheimer's disease (AD). Investigating potential demographic, biological, and clinical determinants of BACE1 in the blood matrix is the critical step to validate and qualify BACE1 bio-indicators for different contexts-of-use (CoU), such as risk assessment, early detection, diagnosis, prognosis, management of AD, and outcome of amyloid pathway targeted drugs. OBJECTIVES: To evaluate the influence of age, sex, HDL-cholesterol and comorbidities (cardiovascular diseases, hypertension, diabetes) on circulating BACE-1 activity. DESIGN: prospective analysis of serum samples, clinical, biological, and demographic variables. SETTING: Three cohorts: 1) Memory Clinic of the Department of Internal Medicine, S. Anna University Hospital, Ferrara (Italy); 2) outpatients attending the Menopause and Osteoporosis Centre (MOC) of the University of Ferrara (Ferrara, Italy); 3) Prevention Center of the University of Ferrara. PARTICIPANTS: 504 cognitively healthy individuals (median age: 62 years, interquartile range: 51-73) and 175 patients with AD (78 years, 74-82). MEASUREMENTS: serum BACE1 (sBACE1), age, sex, HDL-cholesterol, major comorbidities. RESULTS: Age was the strongest independent predictor of sBACE1 variance (ß=0.425, p<0.0001), followed by sex (ß=0.180, p<0.0001), high density lipoprotein-cholesterol (HDL-C) (ß=-0.168, p<0.0001) and hypertension (ß=0.111, p<0.05) (overall model, R2: 0.232). The probability of having elevated sBACE1 activity increased after 70 years of age, with women being more susceptible to higher sBACE1 activity than men. CONCLUSIONS: We provide evidence about potential clinical and biological determinants of sBACE1 activity with a strong association among biomarker, female sex, and older age.

Fulminant hepatitis associated with hepatitis A virus superinfection in patients with chronic hepatitis C.

BACKGROUND: Hepatitis A virus (HAV) infection rarely causes fulminant hepatic failure in people with no underlying liver disease. There are limited data on the course of this infection in patients with chronic hepatitis B and chronic hepatitis C. METHODS: We prospectively followed, from June 1990 to July 1997, 595 adults with biochemical and histologic evidence of chronic hepatitis B (163 patients) or chronic hepatitis C (432 patients) who were seronegative for HAV antibodies. All were tested every four months for serum IgM and IgG antibodies to HAV. RESULTS: Twenty-seven patients acquired HAV superinfection, 10 of whom had chronic hepatitis B and 17 of whom had chronic hepatitis C. One of the patients with chronic hepatitis B, who also had cirrhosis, had marked cholestasis (peak serum bilirubin level, 28 mg per deciliter [479 micromol per liter]); the other nine had uncomplicated courses of hepatitis A. Fulminant hepatic failure developed in seven of the patients with chronic hepatitis C, all but one of whom died. The other 10 patients with chronic hepatitis C had uncomplicated courses of hepatitis A. CONCLUSIONS: Although most patients with chronic hepatitis B who acquired HAV infection had an uncomplicated course, patients with chronic hepatitis C had a substantial risk of fulminant hepatitis and death associated with HAV superinfection. Our data suggest that patients with chronic hepatitis C should be vaccinated against hepatitis A.