The association between inflammatory cytokines and fertility in women with endometriosis

There is a significant positive correlation between cytokine levels from different tissues and fertility in endometriosis patients.

Key Points

Highlights:

• Endometriosis is not only a disease that causes pelvic pain, it is also associated with infertility, and predicting which endometriosis patient would develop infertility is still a matter of research.

Importance:

• Inflammatory cytokines from different tissues including serum, peritoneal fluid, ectopic and eutopic endometrium could be used as non-invasive diagnostic markers to predict the fertility of endometriosis patients.

What’s done here?

• This prospective cohort study was conducted to clarify the association between endometriosis-associated infertility and levels of inflammatory factors.
• Women aged 20-45 years with a histopathologically-confirmed diagnosis of endometriosis were included; those receiving hormonal therapy, having comorbidity and having any other concomitant infertility reason were excluded.
• Participants were divided into two groups: endometriosis-related infertility (Group 1) and women with endometriosis having at least one child  (Group 2) each with 50 participants.
• Inflammatory factors including IL-10, IL-17A, TGF-beta1, and TNF-alpha in serum, peritoneal fluid, the ectopic, and eutopic endometrium tissues were investigated.

Key results:

• There was no significant difference between the groups regarding demographic and clinical data, including age and body mass index.
• TNFa levels from all samples were lower in the infertile group without significance.  
• IL-17A from all tissues in the infertile group were found to be significantly lower except serum, while TGF-beta1 levels in the infertile group were both significantly higher than the non-infertile group except for the peritoneal fluid and ectopic endometrium.
• Similarly, IL-10 levels in the infertile group were significantly higher, except for ectopic endometrium.
• There was a significant positive correlation between IL-17A levels in the peritoneal fluid and those in the eutopic and ectopic endometrium.
• Another significant positive correlation was detected between IL-10 in the serum and that in the peritoneal fluid.

Strengths and Limitations

• This is the first study evaluating the correlation between cytokine levels from different tissues and fertility with stratification of endometriosis patients by fertility status.
• Large sample size and strict exclusion criteria were strengths of this study.
• No evaluation of the causal relationship and absence of randomization was the limitations.

Lay Summary

Women with endometriosis suffer not only from a broad spectrum of symptoms including pain including dysmenorrhea, dyspareunia, and chronic pelvic pain but also fertility problems. Endometriosis-associated infertility develops depending on a combination of several mechanisms such as distorted pelvic anatomy, impaired ovarian function, altered microenvironment, affected endometrial receptivity, and embryo quality. However, we still couldn’t understand which endometriosis patient would develop infertility.

Jin et al,  from China and Germany, published a study titled “Infertile women with endometriosis possess differences in cytokine levels in various tissues” in the journal "Gynecological Endocrinology". The authors aimed to investigate the correlation between levels of inflammatory factors from different tissues and endometriosis-associated infertility. They stratified endometriosis patients by fertility status and compared the levels of IL-10, IL-17A, TGF-beta1, and TNF-alpha in serum, peritoneal fluid, eutopic, and ectopic endometrium tissues.

They found that IL-17A from all tissues in the infertile group were significantly lower except serum, while TGF-beta1 levels in the infertile group were both significantly higher than the non-infertile group except for the peritoneal fluid and ectopic endometrium.

Similarly, IL-10 levels in the infertile group were significantly higher, except for ectopic endometrium. A significant positive correlation was detected between IL-17A from the peritoneal fluid and the ectopic endometrium, and IL-17A from the peritoneal fluid and eutopic endometrium. Additionally, the peritoneal fluid IL-10 levels positively correlated with those in the serum.

“Predicting the fertility of endometriosis patients using noninvasive parameters would be of great clinical value.” the authors added.

Research Source: https://pubmed.ncbi.nlm.nih.gov/35403529/