Intraocular Distribution and Aqueous-Vitreous Correlation of TGF-β Isoforms and GDF-15 in Retinal Diseases.

PURPOSE: To investigate the intraocular distribution and correlation of transforming growth factor-β isoforms and growth differentiation factor-15 in paired aqueous humor and undiluted vitreous samples from patients with various retinal diseases.

METHODS

This prospective cross-sectional study included 51 eyes of 49 patients undergoing pars plana vitrectomy for epiretinal membrane (n = 27), other macular disorders (n = 12), and proliferative diabetic retinopathy (n = 12). Paired aqueous humor and undiluted vitreous samples were collected during surgery. Concentrations of transforming growth factor-β1, transforming growth factor-β2, transforming growth factor-β3, and growth differentiation factor-15 were measured using multiplex immunoassay and enzyme-linked immunosorbent assay. Intraocular distributions were compared, and correlations between aqueous humor and vitreous cytokine concentrations were evaluated using Spearman's rank correlation.

RESULTS

In patients with epiretinal membrane and other macular disorders, transforming growth factor-β1 and transforming growth factor-β2 concentrations were significantly higher in the aqueous humor than in the vitreous body, whereas growth differentiation factor-15 was more abundant in the vitreous. Conversely, in proliferative diabetic retinopathy patients, transforming growth factor-β1, transforming growth factor-β2, and growth differentiation factor-15 levels were significantly higher in the vitreous body. Across all disease groups, a strong positive correlation was observed between aqueous and vitreous growth differentiation factor-15 levels, while no significant correlations were found for any transforming growth factor-β isoforms.

CONCLUSION

Transforming growth factor-β isoforms and growth differentiation factor-15 display distinct intraocular distribution patterns depending on retinal diseases. Notably, growth differentiation factor-15 showed a consistent aqueous-vitreous correlation across disease groups, suggesting that its concentration in the aqueous humor may partially reflect posterior segment conditions and may serve as an indicative marker.