Increased Junctional Zone Stiffness and Serum Small Extracellular Vesicle Proteomic Signatures in...

This study proposed a non-invasive approach combining shear wave elastography (SWE) to measure junctional zone (JZ) stiffness and serum small extracellular vesicle (sEV) proteomics to explore molecular alterations in adenomyosis-associated infertility.

SWE was used to measure JZ stiffness in patients with adenomyosis-associated infertility (n=16) and healthy controls (n=8). An exploratory machine-learning analysis using a support vector classifier and SHAP-based interpretability was performed. For proteomic discovery analysis, four samples were randomly selected from each group. Serum sEVs were isolated from both groups, characterized, and proteomic analysis was conducted.

SWE measurements revealed a significant increase in JZ shear wave velocity in patients with adenomyosis-associated infertility, indicating increased tissue stiffness. Serum proteomic analysis identified 37 downregulated proteins in patients with adenomyosis-associated infertility compared with healthy controls (discovery cohort, n=4 per group). GO enrichment analysis highlighted key terms such as mesoderm development, cell-substrate adhesion, and collagen binding. KEGG analysis identified significant pathways, including extracellular matrix (ECM)-receptor interaction and PI3K-Akt signaling. MSigDB C2 enrichment analysis showed consistent enrichment of ECM- and cell adhesion-related pathways, involving GRB2, ANGPT1, ITGA5, and ITGB1, all of which were downregulated in the adenomyosis-associated infertility group compared with healthy controls.

ECM-related protein dysregulation accompanied by increased JZ stiffness highlights the potential of SWE as a noninvasive approach for assessing uterine changes in this condition. These findings are preliminary and exploratory, requiring validation in larger independent cohorts, and no causal, diagnostic, or mechanistic conclusions can be drawn.