P-303 Calcitonin Gene-Related Protein as a key driver of myometrial fibrogenesis in adenomyosis pathology
Authors: Ye Z , Xin L , Zhang S , Ma L 
Published: July 2024

Abstract

Study question
Does CGRP play a role in the fibrosis of adenomyosis lesions?

Summary answer
CGRP converts fibroblasts to myofibroblasts in adenomyosis lesions via the RAMP1 receptor and participates in the inflammatory activation processes.

What is known already
Adenomyosis is a prevalent and challenging disease in gynecology. It is characterized by the invasion of endometrial glands and mesenchyme into the myometrium, resulting in the development of limited or diffuse lesions. These lesions interact with in situ fibroblasts and recruit immune cells, leading to a chronic and persistent inflammatory microenvironment, which ultimately contributes to myometrial fibrosis. One of the typical clinical symptoms of adenomyosis is secondary progressive dysmenorrhea. Accumulated research suggests that sensory nerves, which are implicated in dysmenorrhea, and neuropeptides such as CGRP play a role in the development of ectopic lesions, thus establishing a feed-forward cycle.

Study design, size, duration
This study employed a laboratory-based experimental design. The in vitro experiment included a total of 67 clinical samples and the in vivo part included 57 ICR mice as subjects, conducted over 20 weeks, with data collection taking place between August 2023 and December 2023.

Participants/materials, setting, methods
Myometrium samples were collected from 37 women with adenomyosis, while control samples were obtained from 30 women without adenomyosis. Among them, the tissues from three adenomyosis patients and three control patients were subjected to scRNA-seq, and the other 61 samples were for validation.
A mouse model of adenomyosis was established by administering tamoxifen. The mice were divided into three groups: a control group, a model group, and a treatment group that received Rimegepant via gavage.

Main results and the role of chance
In adenomyosis tissue, an enrichment of sensory nerve fibers, elevated expression of nerve-related proteins（NGF, PGP9.5）, and increased CGRP expression and its receptor RAMP1 were observed. Furthermore, the qRT-PCR results demonstrated that the adenomyosis lesions were in a chronic inflammatory state which is consistent with the scRNA-seq result. Moreover, the scRNA-seq data suggested a high expression of the CGRP receptor (RAMP1) on fibroblasts, which plays a critical role in causing fibrosis in adenomyosis. Additionally, it was found that CGRP prompted the transition of fibroblasts to myofibroblasts (FMT), and the activated fibroblasts, in turn, attracted macrophages and stimulated their shift towards an M1 phenotype.
These significant findings were further confirmed through experimental animal studies. The fertility outcome indicated a positive trend, with the Rimegepant group showing an increased embryo implantation rate.

Limitations, reasons for caution
In the present experiment, while we have confirmed the involvement of CGRP in the fibrogenesis of adenomyosis, further investigation is needed to understand the specific biological processes occurring in fibroblasts following CGRP administration.

Wider implications of the findings
Limited research has been conducted on the association between adenomyosis and sensory nerves. This study adds the existing evidence by demonstrating the crucial role of sensory nerves and CGRP in promoting fibrosis. The findings of this study offer new perspectives on the treatment and understanding of the pathogenesis of adenomyosis.

Trial registration number
not applicable