Vasoactive intestinal peptide is upregulated in women with endometriosis and chronic pelvic pain

Am J Reprod Immunol. 2018 Sep;80(3):e12857. doi: 10.1111/aji.12857. Epub 2018 Apr 19.


Problem: Chronic pelvic pain (CPP) causes compromised the quality of life in women with endometriosis and is often attributed to local inflammation and ingrowth of nerve fibers. In this pilot study, we aimed to investigate whether the inflammation-related vasoactive intestinal peptide (VIP) and interleukin (IL)-6 were increased in affected patients.

Method of study: Endometrial and endometriotic tissue biopsy specimens, and serum and peritoneal fluid (PF) samples, were obtained from 85 endometriosis patients and 53 controls. VIP and IL-6 analysis and measurement of microvessel density in tissue were performed using immunohistochemistry, Western blotting, RT-qPCR, and ELISA.

Results: Compared with controls, VIP transcript and protein levels were increased in endometrium from endometriosis patients and further elevated in patients with CPP. In addition, microvessel density, a measurement of angiogenic activity, was increased in the endometrium and in endometriosis lesions in the same subset of patients. Serum and PF levels of VIP and IL-6 were higher in women with endometriosis and CPP compared with endometriosis patients who reported no chronic pain.

Conclusion: Vasoactive intestinal peptide is upregulated in endometriosis patients reporting chronic pain. Increased microvessel density in tissue and peritoneal fluid concentrations of IL-6 indicate an elevated inflammation in the pelvic microenvironment of these patients.

Keywords: endometriosis; inflammation; pelvic pain; peritoneal fluid; vasoactive intestinal peptide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Ascitic Fluid / immunology
  • Chronic Disease
  • Endometriosis
  • Endometrium / metabolism*
  • Endometrium / pathology
  • Female
  • Humans
  • Inflammation
  • Interleukin-6 / metabolism*
  • Microvessels / pathology*
  • Pelvic Pain
  • Pilot Projects
  • Quality of Life
  • Vasoactive Intestinal Peptide / metabolism*


  • Interleukin-6
  • Vasoactive Intestinal Peptide