The safety of photochemical tissue bonding for treating damaged corneal epithelium using limbal stem cells pre-cultured on human amniotic membrane

Immunomodulatory effect of human amniotic epithelial cells on restoration of ovarian function in mice with autoimmune ovarian disease

Autoimmune ovarian disease (AOD) is considered to be a major cause of premature ovarian failure (POF). The immunomodulatory properties of human amniotic epithelial cells (hAECs) have been studied in many disease models. We previously reported that hAECs restored ovarian function in chemotherapy-induced POF mice, but the immunomodulatory mechanism of hAECs is still unclear. To investigate the effect of hAECs on recipient mice, especially on regulatory Treg cells, hAECs and hAEC-conditioned medium (hAEC-CM) were intravenously injected into AOD mice immunized with zona pellucida protein 3 peptides (pZP3). Ovarian function was evaluated through estrous cycle, hormone secretion, follicle development, and cell apoptosis analysis. Immune cells including CD3, CD4, CD8 and Treg cells in the spleens were tested by flow cytometry. To elucidate the effect of hAEC-CM on macrophage function, inflammation model in vitro was established in RAW264.7 cells induced by lipopolysaccharide (LPS). hAECs and hAEC-CM regulated estrous cycles, promoted follicle development, ameliorated cell apoptosis and fibrosis in ovaries of AOD mice. In addition, hAECs significantly reversed the decrease of pZP3-induced Treg cells in the spleens. In vitro, hAEC-CM significantly inhibited the inflammatory reaction induced by LPS in RAW264.7 cells via up-regulating the expression of M2 macrophage genes. Further study demonstrated that hAEC-secreted transforming growth factor-beta and macrophage inhibitory factor played important roles in the macrophage polarization and migration under inflammatory stimulation. Taken together, hAECs restored ovarian function by up-regulating Treg cells in the spleens and reduced the inflammatory reaction via modulating the activated macrophage function in a paracrine manner in the ovaries of AOD mice.

Photochemical Cross-Linking for Penetrating Corneal Wound Closure in Enucleated Porcine Eyes

PURPOSE

To compare the efficacy of photochemical-induced tissue cross-linking (PCL), utilizing Rose Bengal (RB) and 532 nm green light irradiation (RB-PCL), with standard sutures for closure of penetrating corneal incision in porcine cadaver eyes.

METHODS

A full-thickness penetrating incision, 3 mm in length parallel to the limbus and perpendicular to the corneal surface, was made in the enucleated porcine cornea. Photochemical cross-linking was performed with tropical RB application and irradiation of 532 nm green light (0.6 W/cm²) for 200, 250, and 300 seconds at laser fluences of 120, 150, and 180 J/cm², respectively, which was compared with the standard 10-0 nylon suture group. Following treatment, intraocular pressure to the point where wound leakage occurred (IOP_L) was measured. Corneal central thickness and surface temperature before and after PCL treatment were recorded. Optical coherence tomography (OCT) and scanning electron microscopy (SEM) were utilized to evaluate wound closure.

RESULTS

The mean corneal central thickness was increased from 812.0 ± 47.0 to 838.0 ± 45.6 µm after the incision as a result of cornea aqueous humor infiltration. RB penetrated approximately 140 μm into the porcine corneal stroma. The mean IOP_L for untreated blank group after incision was 4.27 ± 0.36 mmHg. Increased laser fluences produced increased IOP_L of 27.02 ± 3.01 (PCL₁₂₀), 31.60 ± 3.67 (PCL₁₅₀) and 36.73 ± 3.25 mmHg (PCL₁₈₀), which were statistically different from the control intact group. The mean IOP_L in the sutured cornea was 57.30 ± 4.59 mmHg. The average surface temperature difference before and after PCL treatment was 2.03 ± 0.45-2.47 ± 0.79°C. OCT demonstrated not only complete but also improved closure in comparison with disorganized collagen fibers after conventional suturing, which is further confirmed by SEM.

CONCLUSIONS

Complete and clinically relevant seal of full-thickness porcine corneal incision was achieved using PCL method ex vivo, which provides potential application of this technique in ocular wound closure.