Israel Medical Association Journal

Background: The neurosteroids dehydroepiandrosterone (DHEA) and its sulfated metabolite (DHEAS) have been reported to possess neuroprotective as well as anti-tumoral activity in vitro and in vivo.

Objectives: To compare the effect of the two neurohor­mones on cell viability in primary whole-brain fetal mouse culture and isolated neuronal culture, as well as in a human neuroblastoma cell line (SK-N-SH).

Methods: Cell viability and cell proliferation were deter­mined with the neutral red and ³H-thymidine uptake methods, Apoptosis in propidium iodide-stained neuroblastoma cells was determined using flow cytometry.

Results: DHEA (1 nM-10 ìM) decreased the viability of selected primary neuronal cells (33-95% after 24 and 72 hours) but not of whole-brain cultured cells (neuron+glia). DHEAS did not significantly modify cell viability in either primary culture. In a human neuroblastoma cell line, DHEA (1 nM- 1 ìM) decreased ³H-thymidine uptake (30-60%) and cell viability (23-52%) after 24 hours. DHEAS did not significantly modify, or only slightly stimulated, cell viability and uptake of  ³H-thymidine (132% of controls). The combination of DHEA and DHEAS neutralized the toxic effect of DHEA in both primary neuronal culture and neuroblastoma cell line. Flow cytometric analysis of DNA fragmentation in neuroblastoma cells treated with 100 nM DHEA/DHEAS for 24 hours showed an increase in apoptotic events (31.9% and 26.3%. respec­tively, vs. control 2.54%).

Conclusions: Our results do not confirm a neuroprotective role for DHEA and suggest that DHEA and DHEAS have a differential role: DHEA possesses a neurotoxic (expressed only in isolated neurons) and anti-proliferative effect DHEAS demonstrates only a slight neuroprotective effect.
 

Background: The degree to which serum total cholesterol predicts cariovascular disease is uncertain. While most authors have placed TC among the most powerful risk indicators of CVD, some have claimed that it predicted CVD in women only, or even not at all.

Objective: To determine the predictive value of serum total cholesterol relative to diabetes, smoking, systolic blood pressure and body mass index (kg/m2), for cardiovascular disease mortality in 3,461 occupationally active Israeli males.

Methods: A prospective follow-up was carried out for the years 1987-1998 to determine the effect of age, smoking habits, a history of diabetes, SBP, BMI and TC, at entry, on CVD mortality.

Results: There were 84 CVD deaths during a total of 37,174 person-years follow up. The hazard ratios (95% confidence intervals) for CVD mortality with respect to variables at entry were: diabetes 5.2 (2.1-13.2), age 2.2 (1.7-2.9), smoking 1.3 (1.0-1.8), SBP 1.4 (1.1-2.0), TC 1.5 (1.0-2.1) and BMI 1.2 (0.7-2.2). Among non-obese, non-diabetic, normotensive subjects the hazard ratio of TC adjusted for age and smoking was 1.16 (1.09-1.22) per 10 mg/dl. In the remaining subjects it was 1.04 (0.98-1.12) only. There was a significant interaction between TC and diabetes, hypertension or obesity (P=0.003).

Conclusions: In this population of Israeli males we found an interaction between TC and other risk indicators for CVD. Confirmation is required for the unexpected finding that the predictive value of TC for CVD mortality among non-diabetic, non-obese and normotensive subjects exceeded that among subjects with either of these risk factors.