ORIGINAL ARTICLE Aromatase expression in human peripheral blood leucocytes (PBLs) and in various tissues in primates: studies in elderly humans and cynomolgus monkeys Elisa Pignatti 1,2 , Livio Casarini 1,2 , Sara Scaltriti 1 , Joachim Wistuba 3 , Stefan Schlatt 3 , Alessandra Rossi 1 , Asmaa Lachhab 1 , Erica Taliani 1 , Cesare Carani 1 & Manuela Simoni 1,2 1 Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia Modena, Italy 2 Center of Genome Research (CGR), University of Modena and Reggio Emilia Modena, Italy 3 Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University Mu ¨ nster Mu ¨ nster, Germany Keywords ageing – gene expression – oestrogens – protein production Correspondence Manuela Simoni, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via Giardini 1355, 41126 Baggiovara, Modena, Italy. Tel.: +39 059 3961800; fax: +39 059 3961335; e-mail: manuela.simoni@unimore.it Accepted July 30, 2012. Abstract Background Previous analysis of aromatase gene and protein expression in peripheral blood leucocytes (PBLs), studied in children and adults, was extended to elderly subjects. In addition, we assessed whether aromatase expression in PBLs could be used as a parameter of aromatase expression in other tissues, using the cynomolgus monkey as model. Methods Real-time PCR analysis of aromatase gene expression and protein evaluation by Western blot was performed in PBLs of human elderly subjects and in various tissues from cynomolgus monkeys. Results No gender-related difference in CYP19A1 mRNA and protein expression in PBLs from human elderly women and men was found. In elderly male cynomolgus monkeys, CYP19A1 mRNA and protein were expressed in all cells and tissues analysed, with the lowest levels in PBLs but no clear-cut correlation with other tissues. Conclusions Aromatase expression in PBLs in elderly human subjects is not gender-related and cannot be a surrogate of aromatase expression for other tissues. Introduction Aromatase, a member of cytochrome P450 superfamily, is the key enzyme in vertebrates involved in the conver- sion of testosterone to oestradiol and androstenedione to estrone [28]. The enzyme consists of a haem group and a polypeptide chain of 513 amino-acid residues derived from the CYP19A1 gene localized on chromo- some 15q21.1 [9]. Aromatase is expressed in a large number of cells and tissues [8] in a tissue-specific man- ner, regulated by different promoter regions and by an incompletely understood alternative splicing mechanism [11, 27]. Several studies investigating aromatase expres- sion and/or activity suggest that oestrogen imbalance may result in pathological conditions such as breast cancer, infertility, reproductive defects, metabolic disorders and abnormalities in bone development [8]. Therefore, knowing the physiological and pathological expression and activity of aromatase by tissue, age and gender is of utmost clinical significance. Such studies, however, are hampered by the limitations in obtaining normal human tissue from different organs. Following the identification of a novel exon 1 sequence and its aberrant expression in mammary gland, in fibroblasts and in lymphocytes of patients with aromatase excess syndrome [31], a possible correlation between aromatase in target tissues and in peripheral blood leucocytes (PBLs) was suggested, prompting the study of aromatase in PBLs obtained from young adult women and men and prepubertal children [35]. The comparison between PBL aromatase mRNA and pro- tein level in different ages during the follicular and luteal J Med Primatol 41 (2012) 372–383 © 2012 John Wiley & Sons A/S 372 J Med Primatol doi:10.1111/jmp.12000