Bioengineering

Escherichia coli remains one of the most extensively studied and versatile chassis in synthetic biology, metabolic engineering, and industrial biotechnology [...]

Background: The choriocapillaris (CC), which supplies the outer retina, may be involved in myopic macular degeneration (MMD); however, quantitative in vivo assessment remains challenging. This study aimed to quantify CC thickness (CCT) with swept-source optical coherence tomography (SS-OCT) C-scan imaging and to characterize its changes in MMD. Methods: This study grouped participants into control (CN), simple high myopia (SHM), and pathological myopia (PM) groups. Each group included 30 eyes. Swept-source optical coherence tomography was used to obtain 3 × 3 mm volumetric scans. The choriocapillaris was segmented from the en-face (C-scan) images to determine its thickness and its coefficient of variation. The choroidal thickness (CT), luminal volume, stromal volume, and choroidal vascularity index were quantified from the volumetric data. Results: Reproducibility was excellent (intra- and inter-grader ICCs 0.987 and 0.970). CCT was lower in PM than in CN and SHM (mean differences 9.94 µm and 7.95 µm; both p < 0.001) and slightly lower in SHM than in CN (1.99 µm; p = 0.005), together with increased coefficient of variation in PM. CT and axial length were independently associated with CCT (p = 0.002 and 0.020, respectively). Mediation analysis indicated that choroidal thickness accounted for approximately 52.5% of the association between axial length and choriocapillaris thickness (p < 0.05). CCT distinguished PM from SHM with excellent performance (AUC = 0.996; cutoff 8.9 µm). Conclusions: Choriocapillaris thickness was significantly reduced, with increased relative spatially heterogeneous in MMD. It was associated with axial length and choroidal thickness and showed excellent discriminatory performance.

(1) Background: Meshed split skin grafting (SSG) still remains the gold standard of care for deep wound treatment. The aim of this study was to evaluate an autologous bioengineered dermal–epidermal composite skin for treating full-thickness wounds in a porcine model using a clinically relevant two-stage grafting approach. (2) Methods: Multiple full-thickness wounds were created on the dorsal sites of animals. Wounds were initially grafted with a polyurethane dermal template, followed three weeks later by either Platelet hydroGel–Pig Skin Equivalent (PG-PSE) or meshed SSG control. Human platelet lysate was also assessed as a substitute for foetal calf serum during skin maturation. (3) Results: By two weeks post-grafting, epidermisation of PG-PSE-treated wounds were comparable to SSG-treated wounds. EdU labelling confirmed early engraftment and contribution of graft-derived cells to both neo-epidermis and neo-dermis. Cytokeratin 5+ immunofluorescence staining, showed a hyperproliferative neo-epidermis, enriched in progenitor keratinocytes, typical of early-stage skin grafts in pigs. Neo-dermis was marked with abundance of vimentin⁺ fibroblasts and rete ridges indicating a mature dermal–epidermal junction. Robust neovascularisation was observed in both superficial and deep neo-dermis, with platelet lysate-matured grafts showing greater microvessel formation in superficial neo-dermis in comparison with native skin. Picrosirius red staining of the superficial neo-dermis revealed a lower abundance of thick, red collagen fibres in PG-PSE grafts compared to SSGs, consistent with ongoing collagen deposition and tissue integration in PG-PSE. However, the ratio of thin green collagen fibres to thick red collagen fibres in the deep neo-dermis was largely comparable between group conditions, suggesting that bioengineered grafting does not alter dermal template maturation. (4) Conclusion: Overall, autologous dermal–epidermal bioengineered skin effectively vascularises and repairs wounds over a dermal template. Platelet lysate is a promising alternative to foetal calf serum, although PG-PSE may require longer time for complete dermal maturation and warrants further long-term evaluation.