Abstract
Purpose :
As a major component of the optic nerve microenvironment (ONM), meningothelial cells (MECs) cover the arachnoid, the pia and the inner wall of the dura mater as well as the trabeculae and septae within the subarachnoid space (SAS) of the brain and the optic nerve. These cells play a central role in the maintenance of cerebrospinal fluid (CSF) homeostasis and in physiological and pathophysiological processes within the SAS. To study the role of MECs, more advanced and physiologically relevant models which account for the intricate three-dimensional architecture of the SAS and the factors influencing this delicate microenvironment are required. Therefore, we developed a perfusion bioreactor-based 3D model using primary human MECs to mimic the ONM. We employ this model to study the function of MECs during optic nerve compartmentalization (ONC), a syndrome characterized by impaired CSF flow within the optic nerve SAS and linked to normal tension glaucoma and idiopathic intracranial hypertension.
Methods :
Primary human MECs were seeded into a 3D porous collagen scaffold within a U-CUP perfusion bioreactor (Cellec Biotek) and cultured for 72 hours under physiological flow conditions (0.3 mm/s) to generate a meningothelial like tissue. Using immunohistochemistry, engineered ONM were compared to human samples in terms of marker protein expression. As MECs have previously been shown to act as phagocytes, functionality of MECs was assessed measuring phagocytotic activity. In addition, the response of MECs to conditions of pathophysiological flow dynamics in the ONM (0.01 mm/s) are being analysed.
Results :
After 3 days of culture MECs proliferated, lining the entire scaffold. Our 3D model of the ONM revealed comparable histological characteristics to the human meningothelial cell layer of the SAS with regards to cell-cell interaction markers for gap-junctions, tight- junctions and desmosomes, thus closely resembling the in vivo situation. Functionally, MECs in 3D culture displayed strong phagocytotic activity as observed previously under standard culture conditions.
Conclusions :
This novel perfusion bioreactor based 3D model of the ONM closely imitates the in vivo microenvironment of the optic nerve, making it an ideal in vitro model for studying fundamental aspects of MEC function and the role of MECs in ONC under physiologically relevant conditions.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.