Endocrine Abstracts

Objective: Aromatase, the key enzyme involved in estrogen synthesis, is expressed in a variety of cells and tissues including human peripheral blood leukocytes (PBLs). The present study was designed to evaluate PBL aromatase gene expression in male and female elderly subjects compared to young male controls.

Design: CYP19A1 mRNA and protein were measured in PBLs obtained from young men (n=13) aged < 35 years, postmenopausal women (n=13) and men (n=13) aged between 50 and 60 years, as well as elderly men (n=13) and women (n=13), both aged > 70 years. All subjects gave written informed consent to participate in the study.

Methods and results: Aromatase mRNA measured by real-time PCR in PBLs was not significantly different in any group compared to young men mainly due to high inter-individual variation in expression levels within the same group. Immunoblot analysis confirmed the data obtained by real-time PCR showing levels of aromatase protein very variable within the single groups and a scarce correlation between the levels of transcripts and the relative quantity of protein. However subjects with hypertension showed statistically significant higher levels of CYP19A1 mRNA. No other correlations were found.

Conclusions: CYP19A1 mRNA and protein are not differentially expressed in PBLs from adult and elderly women and men. It is postulated that in these cells aromatase produces estrogens whit paracrine activity on development and maintenance of the immune system. We speculate that increased aromatase transcription in PBLs, can be indicative of the presence of a pathological and/or proinflammatory state, such as a hypertensive state.