Material context and TGF-β blockade timing determine retained matrix in patient-derived bioprinted keratoconus stroma

Patient-derived bioprinted keratoconus stroma demonstrated that material context and TGF-β blockade timing are crucial factors in retaining matrix. Researchers created GelMA stromas from both keratoconus and normal donor cells to study the impact of these factors.

In the KC bioprinted stromas, cells maintained disease-associated transcription while secreting normal amounts of procollagen I and lumican compared to their normal counterparts. When compared to two-dimensional cultures and matched cast GelMA, the three-dimensional environment improved matrix induction and reduced resting contractile expression.

Printing also introduced a stromal identity response, which was retained as lumican. The researchers found that delaying TGF-β1 blockade after a pulse helped preserve matrix transcription and late secretion. After 11 days of blockade withdrawal, donors who experienced this finite course retained more native collagen and had lower contractile-gene expression compared to the vehicle group in 9 out of 12 donors.

The study showed that choosing a finite blockade regimen based on retained collagen, rather than secretion, differed the timing in half of the donors. In half of the cases, the chosen regimen resulted in 22.2% more collagen. Retained collagen and contractile expression can serve as joint endpoints for determining when to initiate and discontinue TGF-β pathway treatments, such as losartan and TGF-β3, for keratoconic and scarred corneas.