New Approach Methodologies: Microphysiological Systems for Preclinical Research

So-called new approach methodologies (NAMs) including human cell-based microphysiological systems (MPS) are poised to revolutionize preclinical science and improve the success rate of candidate therapeutics in clinical trials. To achieve these goals, it will be critical to capture aspects of individual physiological differences such as biological sex and hormone status in microphysiological systems and other NAMs. Sex-specific cell culture methods and MPS can enhance our understanding of how biological sex influences health and disease. Our laboratory has demonstrated baseline sex differences in numerous 2D culture and MPS bioassays when a common cell culture medium is used for both sexes. To address this limitation, we developed sex-specific culture methods based on culturing female cells with estradiol and male cells with dihydrotestosterone, the concentrations of which can be tuned to yield sex-equivalent baselines in select 2D and MPS bioassays. This talk will emphasize the application of these culture methods to create sex-specific MPS models of diabetic retinopathy. Sex-matched combinations of primary human retinal microvascular endothelial cells and ocular fibroblasts were used to construct MPS models of an endothelial barrier and vascular beds. Estradiol protected against pathological changes induced by diabetic culture conditions, such as increased barrier permeability and basement membrane thickening, in female but not male models. Dihydrotestosterone failed to protect against pathological changes in both female and male models. These results are compatible with clinical observations of increased incidence and severity in male patients. Further refinement of sex-specific MPS will enable the investigation of sex-based precision therapies that target sex hormone signaling in diabetic retinopathy and other diseases. 

Learning Objectives:

1. Describe how new approach methodologies (NAMs) and microphysiological systems (MPS) can improve preclinical research and therapeutic development.

2. Differentiate the impact of sex-specific cell culture methods on baseline responses in 2D and MPS bioassays.

3. Interpret findings from sex-specific MPS models of diabetic retinopathy to evaluate implications for precision therapies.