A Simple Mathematical Model Demonstrates the Potential for Cell-Based Hormone Therapy to Address Dysregulation of the Hypothalamus-Pituitary-Ovary Axis in Females with Loss of Ovarian Function.

Tissue-engineering and cell-based strategies provide an intriguing approach to treat complex conditions such as those of the endocrine system. We have previously developed a cell-based hormone therapy (cHT) to address hormonal insufficiency associated with the loss of ovarian function. To assess how the cHT strategy may achieve its efficacy, we developed a mathematical model to determine if known autocrine, paracrine, and endocrine effects of the native hypothalamus-pituitary-ovary (HPO) axis could explain our previously observed effects in ovariectomized rats following treatment with cHT. Our model suggests that cHT constructs participate in the complex machinery of the HPO axis. We were able to describe the in vivo behaviors of estrogen, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), inhibin, and androgen with good accuracy. A sensitivity analysis indicated that some parameters impact the broader HPO system more than others, but that most changes in model parameters led to proportional changes in the system. We also conducted a predictive analysis on the effect of cHT dose on HPO axis hormones and found that, with the exception of estrogen, the other HPO hormones analyzed reach a saturation level within the physically possible number of constructs.