Endocrine Abstracts

Background: The human adrenal cortex is composed of different zones, namely the zona glomerulosa (ZG), zona fasciculata (ZF), zona reticularis, and the recently proposed undifferentiated zone (UZ). The adrenal cortex synthesises and secretes steroids, mainly aldosterone and cortisol, both responsible for essential physiological and metabolic functions. Adrenal cortex disorders can be life threatening and current treatment involves life-long steroid replacement, which is not ideal.

Aim: We aim at identifying markers to distinguish (and eventually isolate) cells from the different zones, with a specific focus on the subcapsular region.

Methods: Following ethical approval, adrenal glands were collected from patients undergoing adrenalectomy, snap–frozen in liquid nitrogen and cut using a cryostat. We tested a wide array of antibodies to antigens known to have a zonal expression in murine studies. Non-radioactive in situ hybridization was also employed.

Results: We demonstrated that the human ZU is a more complex environment than we had anticipated. Delta-like homologue-1 (DLK1) seems to be a good marker of the ZU; however we found clusters of non-steroidogenic cells in the subcapsular region that are DLK1 negative and we are currently searching for specific markers.

Conclusion: The detailed characterisation of the subcapsular region in the human adrenal will provide invaluable information of steroidogenic differentiation processes and tissue homeostasis. It will also aid in the isolation of cells from the different zones using laser capture microdissection followed by important downstream applications, such as a transcriptome comparative analysis.