Morphological and functional features of spiral arteries in chronic endometritis of varying severity

Introduction. Long-term chronic inflammation in the endometrium leads to sclerotic changes, disorders in the extracellular matrix and intercellular interactions, and, ultimately, to impaired formation of spiral arteries and hypoperfusion. The study aimed to compare morphological and functional changes in spiral arteries of the endometrium in patients with chronic endometritis of varying severity. Materials and methods. The research included ninety-five 20–40-year-old female patients that were divided into two groups. The main group comprised 60 patients with a history of abnormal uterine bleeding, and the comparison group consisted of women who underwent routine medical examinations. All women underwent diagnostic hysteroscopy with an endometrial pipelle biopsy on days 7–11 with a 28-day menstrual cycle. In histological sections stained with hematoxylin and eosin, we diagnosed chronic endometritis with immunohistochemical reaction with CD138 antibodies and counted the number of plasma cells. In addition, the presence or absence of fibrosis in the endometrial stroma was detected using Mallory staining. We assessed the external diameter of spiral arteries, vessel lumen diameter, and vessel lumen area. Results. We detected significant changes in blood vessels depending on the severity of chronic endometritis. These changes indicate the impaired formation of spiral arteries in the patients with a history of abnormal uterine bleeding associated with chronic endometritis. Conclusion. Our results allowed us to interpret the impaired biotransformation of the vascular compartment in patients with chronic inflammation, which has fundamental importance in the regulation of reproductive and menstrual functions. The severity of chronic endometritis directly affects pathological changes in the formation of spiral arteries in patients with a history of abnormal uterine bleeding. The established significant changes in endometrial blood vessels describe the mechanisms of pathogenesis of endometrial hypoxia followed by stromal fibrosis, hypoplasia, and hypoplastic endometrium formation, which causes impaired endometrial functioning. Keywords: chronic endometritis, abnormal uterine bleeding, vessel formation, morphometry