Uterine innervation in adenomyosis

Area of Science:

• Gynecologic Pathology
• Neuroscience
• Reproductive Biology

Background:

• Adenomyosis is a common gynecological condition characterized by the presence of endometrial glands and stroma within the myometrium.
• Uterine innervation plays a role in physiological processes, including myometrial contractility and pain perception.
• Alterations in nerve distribution may contribute to the symptoms associated with adenomyosis.

Purpose of the Study:

• To investigate and characterize the innervation patterns of the uterus in cases of adenomyosis.
• To compare the nerve distribution in uteri with adenomyosis to histologically normal uteri.
• To determine if specific nerve fiber changes are associated with the presence and location of adenomyosis.

Main Methods:

• Retrospective analysis of uterine tissue sections from two groups: normal uteri and uteri diagnosed with adenomyosis.
• Immunohistochemical staining for nerve fibers using PGP 9.5.
• Histopathological examination of the uterine isthmus, focusing on the endometrial-myometrial interface and areas of adenomyosis.

Main Results:

• Normal uterine innervation shows nerve concentrations in subserosal layers and at the endometrial-myometrial interface, with sparse neurovascular bundles in the myometrium.
• Uteri with adenomyosis exhibited an absence of nerves within the adenomyotic tissue and at the endometrial-myometrial nerve plexus.
• Focal proliferation of small-diameter nerve fibers was observed at the margins of adenomyosis in some cases, while subserosal nerves remained present.

Conclusions:

• Adenomyosis is associated with a significant loss of nerve fibers at the endometrial-myometrial interface.
• Nerve fibers are largely absent within the ectopic endometrial-stromal tissue characteristic of adenomyosis.
• These alterations in uterine innervation may have implications for understanding the pathophysiology and symptoms of adenomyosis, such as pain and abnormal uterine bleeding.