Unraveling the fibrotic microenvironment in intrauterine adhesions through integrated metabolomics and proteomics.

BACKGROUND

Intrauterine adhesions (IUA) result from endometrial basal layer injury, leading to fibrous tissue formation and impaired fertility. Current treatments fail to fully reverse the fibrotic microenvironment. This study aimed to elucidate molecular mechanisms underlying IUA-associated fibrosis through integrated metabolomics and proteomics.

METHODS

Fibrotic tissues from 35 moderate-to-severe IUA patients and normal endometrial samples from 20 controls were collected during hysteroscopy. Metabolomic profiling was performed using UPLC-MS, and proteomic analysis using label-free quantitative mass spectrometry. Differential metabolites (DEMs) and proteins (DEPs) were identified via OPLS-DA and statistical criteria (VIP > 1, P < 0.05 for DEMs; FDR-adjusted P < 0.05, FC ≥ 2 or ≤ 0.5 for DEPs). KEGG enrichment and integrated correlation analyses were conducted to explore pathway alterations and metabolite-protein interactions.

RESULTS

A total of 565 DEMs were identified, primarily lipids, organic acids, and organooxygen compounds. KEGG enrichment revealed significant alterations in carbohydrate and amino acid metabolism pathways, with downregulation of TCA cycle intermediates and upregulation of glucose-6-phosphate, arginine, and methionine sulfoxide. Proteomics identified 2763 DEPs, with up-regulated proteins enriched in focal adhesion and ECM-receptor interaction pathways, and down-regulated proteins in DNA replication and complement cascades. Integrative analysis showed that carbohydrate and amino acid metabolism-related DEMs correlated negatively with fibrosis-related DEPs (e.g., collagens, TGF-β-related proteins), while focal adhesion-related DEPs correlated positively with fibrosis markers. Notably, fumarate showed strong negative correlations with COL18A1 (r=-0.71) and positive correlation with E-cadherin (r = 0.61).

CONCLUSIONS

This multi-omics study reveals that metabolic reprogramming, particularly involving glycolysis and amino acid metabolism, is closely associated with activation of the integrin-focal adhesion signaling pathway in IUA fibrosis. These findings provide new insights into potential therapeutic targets for endometrial repair and fertility preservation.