Review of neutrophil based scientific research in endometriosis

Neutrophils are still unresolved in endometriosis pathophysiology

Key Points

Highlights:                  

• Neutrophils are considered the primary cellular response in various immunoinflammatory conditions. 
• Scientific research has suggested that the local microenvironment could influence neutrophil polarization and the development of chronic diseases such as endometriosis.

Importance:

• Endometriosis foci have rapid neutrophil recruitment which contributes to early angiogenesis and positive feedback through cytokines resulting in a pathogenetic role in endometriosis.

What's done here:

• In this comprehensive review, the authors have made an extensive search in Pubmed and Medline for publications regarding the involvement of neutrophils in endometriosis pathophysiology.
• Neutrophil abundance, function, and activation status of their populations, as well as the role of their heterogeneity and plasticity in endometriotic lesions, were evaluated.

Key Results:

• Based on present scientific research data, it is not possible to conclude whether neutrophil phenotype and function contribute to the formation and progression of endometriosis lesions.
• It is expected that the role of neutrophil populations could be better understood using high-throughput sequencing platforms, single-cell genomics, and multi-omics techniques.

Lay Summary

Xinlei Wang and associates from Jilin University, Changchun, China, have published a comprehensive review on the pathogenetic role of neutrophils in endometriosis in a recent issue of the periodical  “Mediators of inflammation”.

As a common inflammatory condition where endometrial tissue exists outside the uterine cavity, endometriosis is now widely acknowledged as a final consequence of immune dysfunction. The most widely accepted classical endometriosis theory is retrograde menstruation but although a great number of women have this retrograde menstruation only a fraction of them develop endometriosis.

It is well known that an altered proinflammatory immune milieu exists in endometriotic foci however there is still a knowledge gap regarding the altered functional properties of specific cells and how this may lead to changes in endometriosis phenotype and illness.

The authors have made an extensive database search on PubMed and Medline among articles published up to 30 November 2022. Endometriosis, neutrophils, neutrophil extracellular traps, pelvic microenvironment, angiogenesis, inflammation, and cytokines were all combined as search terms. The search included both human and animal studies but not editorials, communications, and notes.  After an extensive evaluation, a total of 19 articles were found worth analyzing.

There is a widely accepted hypothesis that women with congenital and adaptive immune defects are more likely to have endometriosis. At a final consensus of all known parameters, the influence of estrogen, immune dysfunction, and angiogenesis is considered to be important in endometriosis pathogenesis. Endometriotic foci lead to quick neutrophil aggregation which contributes to early angiogenesis in this ectopic microenvironment, which forms a positive feedback.

The authors conclude that the present evidence can not reveal whether neutrophil phenotype and function have a role in the formation and progression of endometriotic foci. The neutrophil-based scientific publications have been observational, with neutrophils or their cytokine products assessed in the systemic circulation and peritoneal fluid alone or in combination. The mechanisms of neutrophils in endometriosis pathogenesis would be better understood using sequencing platforms, single-cell genomics, and multiomics techniques is the final remark of the reviewers.

Research Source: https://pubmed.ncbi.nlm.nih.gov/36762287/