Engineering next-generation in vitro platforms for endocrine disruptor testing via bioprinting

The endocrine system is essential for correct human physiology and controls the ability of the human body to develop, grow, and reproduce through the synthesis and release of hormones. In recent decades, numerous studies have highlighted the presence of chemicals that are able to interfere with and damage the functionality of the endocrine system. These compounds have been identified as endocrine disruptors (EDs), and they can have serious effects on human health. Despite this knowledge, functional endocrine gland in vitro models that can be used for the study of endocrine gland development and disease progression and for the evaluation of potential EDs in vitro are lacking. In this review, we provide an overview of the major components of the endocrine system, as well as of the most well-known EDs and their mode of action. With a focus on the thyroid gland, the largest endocrine gland of the body, we report on the current in vitro models available for the evaluation of ED toxicity and mode of action. Finally, we describe new technologies that have been employed for the production of innovative in vitro models.