Background

To evaluate whether subretinal or intravitreal injection of human CD34+ bone marrow-derived stem cells (BMSC) can have protective effects on retinal degeneration that may be enhanced by coadministration of exosomes harvested from human bone marrow mesenchymal stem cells (MSCs).

Methods

Human CD34+ cells were harvested from the mononuclear cell fraction of bone marrow using magnetic beads and labeled with EGFP. Exosomes were harvested from cultured human MSCs under hypoxic conditions. Royal College of Surgeons (RCS) 3-weeks-old rats, immunosuppressed with cyclosporine A, received subretinal or intravitreal injection of CD34+ cells (50,000 cells), CD34+ cells with exosomes (50,000 cells+10 µg), exosomes alone (10 µg), or PBS. Retinal function was examined using electroretinography (ERG), and the eyes were harvested for histologic and immunohistochemical analysis.

Results

The b-wave amplitude of ERG at 2 weeks after injection was significantly higher in eyes with subretinal or intravitreal CD34+ BMSC alone or in combination with exosomes when compared to PBS injected eyes or untreated contralateral eyes. At 4 weeks after injection, the ERG signal decreased in all groups but eyes with subretinal CD34+ BMSCs alone or combined with exosomes showed partially preserved ERG signal and preservation of the outer nuclear layer of the retina near the injection site on histology when compared to eyes with PBS injection. Immunohistochemical analysis identified the human cells in the outer retina. Subretinal or intravitreal exosome injection had no effect on retinal degeneration when administered alone or in combination with CD34+ cells.

Conclusions

Both subretinal and intravitreal injection of human CD34+ BMSCs can provide functional rescue of degenerating retina, although the effects were attenuated over time in this rat model. Regional preservation of the outer retina can occur near the subretinal injection site of CD34+ cells. These results suggest that CD34+ cells may have therapeutic potential in retinal degeneration.

Purpose

To analyse the intraocular pressure rise after intravitreal dexamethasone implant (Ozurdex) amongst different geographic populations.

Methods

The medical charts of 294 dexamethasone implants between February 2011 and 2017 were reviewed retrospectively. South Asian (India), White (Europe, US and Israel) Latino (Argentina and Brazil) patient data was included in the study. Ocular hypertension (OHT) was defined as intraocular pressure of >25 mmHg or an increase of at least 10 mmHg from baseline. The main indications for treatment were diabetic macular edema (ME) (65.6%), retinal vein occlusion (26.5%), uveitis (7.8%).

Results

Amongst 294 intravitreal implants, ocular hypertension (>25 mmHg) was recorded in 0, 8 and 9.5% in White, Latino, and South Asian groups, respectively. However, IOP > 20 mmHg was recorded in 14%, 28% and 27% in White, Latino, and South Asian groups, respectively. Incidence of very high IOP (>35 mmHg) was lower in all geographical groups. It was 3% in Latino followed by 2% in South Asian group.

Conclusion

Latino and South Asian groups have higher IOP rise compared to White population. Most patients with elevated IOP fluctuate between 20-25 mmHg.