# Transplantation and Noninvasive Longitudinal In Vivo Imaging of Parathyroid Cells: A Proof-of-Concept Study

## TL;DR

This study introduces a new method for transplanting and imaging parathyroid cells in live mice to better understand their function and disease.

## Contribution

A novel platform for parathyroid cell transplantation and noninvasive in vivo imaging using the anterior chamber of the eye.

## Key findings

- Parathyroid adenoma tissue transplanted into the mouse eye engrafted onto the iris and became vascularized.
- Transplanted animals showed elevated PTH levels, indicating functional grafts.
- In vivo confocal microscopy enabled repeated monitoring of graft morphology and vascularization.

## Abstract

The parathyroid cell is a vital regulator of extracellular calcium levels, operating through the secretion of parathyroid hormone (PTH). Despite its importance, the regulation of PTH secretion remains complex and not fully understood, representing a unique interplay between extracellular and intracellular calcium, and hormone secretion. One significant challenge in parathyroid research has been the difficulty in maintaining cells ex vivo for in-depth cellular investigations. To address this issue, we introduce a novel platform for parathyroid cell transplantation and noninvasive in vivo imaging using the anterior chamber of the eye as a transplantation site. We found that parathyroid adenoma tissue transplanted into the mouse eye engrafted onto the iris, became vascularized, and retained cellular composition. Transplanted animals exhibited elevated PTH levels, indicating a functional graft. With in vivo confocal microscopy, we were able to repetitively monitor parathyroid graft morphology and vascularization. In summary, there is a pressing need for new methods to study complex cellular processes in parathyroid cells. Our study provides a novel approach for noninvasive in vivo investigations that can be applied to understand parathyroid physiology and pathology under physiological and pathological conditions. This innovative strategy can deepen our knowledge on parathyroid function and disease.