Plasma proteins and persistent postsurgical pelvic pain among adolescents and young adults with endometriosis

Abstract

Background: Noninvasive biomarkers that predict surgical treatment response would inform personalized treatments and provide insight into potential biologic pathways underlying endometriosis-associated pain and symptom progression.

Objective: To use plasma proteins in relation to the persistence of pelvic pain following laparoscopic surgery in predominantly adolescents and young adults with endometriosis using a multiplex aptamer-based proteomics biomarker discovery platform.

Study design: We conducted a prospective analysis including 142 participants with laparoscopically-confirmed endometriosis from the Women's Health Study: From Adolescence to Adulthood observational longitudinal cohort with study enrollment from 2012-2018. Biologic samples and patient data were collected with modified World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonization Project tools. In blood collected before laparoscopic ablation or excision of endometriosis, we simultaneously measured 1305 plasma protein levels, including markers for immunity, angiogenesis, and inflammation, using SomaScan. Worsening or persistent postsurgical pelvic pain was defined as having newly developed, persistent (ie, stable), or worsening severity, frequency, or persistent life interference of dysmenorrhea or acyclic pelvic pain at 1-year postsurgery compared with presurgery. We calculated odds ratios and 95% confidence intervals using logistic regression adjusted for age, body mass index, fasting status, and hormone use at blood draw. We applied Ingenuity Pathway Analysis and STRING analysis to identify pathophysiologic pathways and protein interactions.

Results: The median age at blood draw was 17 years (interquartile range, 15-19 years), and most participants were White (90%). All had superficial peritoneal lesions only and were treated by excision or ablation. One-year postsurgery, pelvic pain worsened or persisted for 76 (54%) of these participants with endometriosis, whereas pelvic pain improved for 66 (46%). We identified 83 proteins associated with worsening or persistent pelvic pain 1-year postsurgery (nominal P<.05). Compared with those with improved pelvic pain 1-year postsurgery, those with worsening or persistent pelvic pain had higher plasma levels of CD63 antigen (odds ratio, 2.98 [95% confidence interval, 1.44-6.19]) and CD47 (odds ratio, 2.68 [95% confidence interval, 1.28-5.61]), but lower levels of Sonic Hedgehog protein (odds ratio, 0.55 [95% confidence interval, 0.36-0.84]) in presurgical blood. Pathways related to cell migration were up-regulated, and pathways related to angiogenesis were down-regulated in those with worsening or persistent postsurgical pelvic pain compared with those with improved pain. When we examined the change in protein levels from presurgery to postsurgery and its subsequent risk of worsening or persistent postsurgical pain at 1-year follow-up, we observed increasing levels of Sonic Hedgehog protein from presurgery to postsurgery was associated with a 4-fold increase in the risk of postsurgical pain (odds ratio [quartile 4 vs 1], 3.86 [1.04-14.33]).

Conclusion: Using an aptamer-based proteomics platform, we identified plasma proteins and pathways associated with worsening or persistent pelvic pain postsurgical treatment of endometriosis among adolescents and young adults that may aid in risk stratification of individuals with endometriosis.

Keywords: EPHect; adolescents; endometriosis; pain persistence; pelvic pain; proteomics; sonic hedgehog protein; surgery.

Figure 1.. Protein-protein interaction clusters and relevant pathways associated with worsening/persistent pelvic pain at Year 1 using STRING analysis (k-means = 6 clusters indicated by node color).

Protein-protein interaction network was created based on the 83 proteins that were significantly associated with worsening/persistent pelvic pain at Year 1 with unadjusted p-value <0.05. Related functional categories are labeled based on proteins with their reported functional involvement in the pathways of angiogenesis (red node), activation of leukocytes (green node), cell migration (light-green node), and neuropeptides (blue node). Solid line represents within-cluster, dashed gray line represents between-cluster interactions. Line thickness indicates strength of data support.

Figure 2.. Biological pathways associated with risk of worsening/persistent pelvic pain one-year after surgery (p-value <1.3×10⁻¹²).

Biological pathways associated with risk of worsening/persistent pelvic pain are grouped by the direction of association (i.e., activation z-score) and presented within group ordered by p-value. Upregulated pathways are denoted by red bubbles and downregulated pathways are denoted by blue bubbles. Of the top 20 statistically significant pathways, three pathways (morphology of cardiovascular system, morphology of vasculature, and morphology of body cavity pathways) were removed due to activation z-score of 0.0.

Figure 3.. Relative percent change in Sonic hedgehog (SHH) protein levels across pre- and post-surgical blood collections and its association with subsequent risk of having persistent/worsening pain at 1-year post-surgery.

The table is showing the odds ratios (95% CIs) of having worsening/persistent pelvic pain one-year after surgery by increasing change in SHH levels in quartiles from pre- to post-surgery. The figure below is the plotting the change in SHH levels from pre- and post-surgery in each quartiles.