Infectious Keratitis After Ocular Surface Stem Cell Transplantation

Citrobacter keratitis: predisposing factors and clinical characteristics

PURPOSE

To report predisposing factors, clinical presentation, antibiotic sensitivity, and management of Citrobacter-caused infectious keratitis.

METHODS

We retrospectively reviewed the medical records of culture-proven cases of Citrobacter keratitis in a tertiary referral center for 8 years (from January 2012 to September 2020). Demographic data of the patients, predisposing factors, and presenting signs were extracted.

RESULTS

Eighteen cases of microbial keratitis due to Citrobacter spp. were identified. The median age of the patients was 66 years (range: 10-89, interquartile range : 59-81). Thirteen patients were male and 5 were female. Multiple predisposing factors were identified in all eyes, including ocular surface disease (n = 8), previous corneal surgery (n = 6), and history of ocular trauma (n = 6). Five patients were diabetic. Corrected distance visual acuity (CDVA) of patients was light perception (LP) in 8 patients, hand motion (HM) in 7, counting fingers (CF) at 1 m in 1, and CF at 2 m in 2 patients. Thirteen eyes exhibited hypopyon. An area of corneal thinning was observed in 7 eyes (38.9%). Endophthalmitis due to infectious keratitis developed in one patient. In vitro susceptibility testing confirmed high sensitivity to ceftazidime and aminoglycosides. Medical management consisted primarily of topical amikacin (20 mg/ml) combined with topical cefazoline (50 mg/ml) (72.2%). Surgical tectonic procedures were carried out in 7 eyes (38.9%).

CONCLUSION

Citrobacter spp. is a rare cause of bacterial keratitis.Previous keratoplasty and ocular surface problems are important risk factors. The prognosis is not good and surgical tectonic intervention is required in many cases to resolve the corneal infection.

Rapid bioprinting of conjunctival stem cell micro-constructs for subconjunctival ocular injection

Ocular surface diseases including conjunctival disorders are multifactorial progressive conditions that can severely affect vision and quality of life. In recent years, stem cell therapies based on conjunctival stem cells (CjSCs) have become a potential solution for treating ocular surface diseases. However, neither an efficient culture of CjSCs nor the development of a minimally invasive ocular surface CjSC transplantation therapy has been reported. Here, we developed a robust in vitro expansion method for primary rabbit-derived CjSCs and applied digital light processing (DLP)-based bioprinting to produce CjSC-loaded hydrogel micro-constructs for injectable delivery. Expansion medium containing small molecule cocktail generated fast dividing and highly homogenous CjSCs for more than 10 passages in feeder-free culture. Bioprinted hydrogel micro-constructs with tunable mechanical properties enabled the 3D culture of CjSCs while supporting viability, stem cell phenotype, and differentiation potency into conjunctival goblet cells. These hydrogel micro-constructs were well-suited for scalable dynamic suspension culture of CjSCs and were successfully delivered to the bulbar conjunctival epithelium via minimally invasive subconjunctival injection. This work integrates novel cell culture strategies with bioprinting to develop a clinically relevant injectable-delivery approach for CjSCs towards the stem cell therapies for the treatment of ocular surface diseases.

Aniridia and Axenfeld-Rieger Syndrome: Clinical presentations, molecular genetics and current/emerging therapies

Aniridia and Axenfeld-Rieger Syndrome are related, human ocular disorders that are typically inherited in an autosomal dominant manner. Both result from incorrect development of the eye and have, as their most serious consequences, elevated risk to develop the blinding condition glaucoma. This review will focus on describing the clinical presentations of Aniridia and Axenfeld-Rieger Syndrome as well as the molecular genetics and current and emerging therapies used to treat patients.

Long-Term Results of Cultured Limbal Stem Cell Versus Limbal Tissue Transplantation in Stage III Limbal Deficiency

We aimed to evaluate efficiency and safety of transplantation of limbal stem cells (LSC) cultured on human amniotic membrane with no feeders and to compare cultured LSC with limbal tissue transplantation. Thirty eyes with stage III LSC deficiency were treated with autologous (autoLSC) or allogeneic (alloLSC) cultured LSC transplantation (prospective phase II clinical trial; average follow-up time, 72 months) or autologous (autoLT) or allogeneic (alloLT) limbal tissue transplantation (retrospective control group; average follow-up time, 132 months) between 1993 and 2014. The 5-year graft survival defined by absence of recurrence of the clinical signs of limbal deficiency was 71% for autoLSC, 0% for alloLSC, 75% for autoLT, and 33% for alloLT. Visual acuity improved by 9.2 lines for autoLSC and 3.3 lines for autoLT. It decreased by 0.7 lines for alloLSC and 1.9 lines for alloLT. Adverse events were recorded in 1/7 autoLSC, 7/7 alloLSC, 6/8 autoLT, and 8/8 alloLT patients. Corneal epithelial defect was the only adverse event recorded after autoLSC, whereas severe sight-threatening adverse events were recorded in the remaining three groups. Compared with failed grafts, successful grafts featured greater decrease in fluorescein staining, greater superficial vascularization-free corneal area, lower variability of the corneal epithelial thickness, and higher corneal epithelial basal cell density. Autologous cultured LSC transplantation was associated with high long-term survival and dramatic improvement in vision and was very safe. Autologous limbal tissue transplantation resulted in similar efficiency but was less safe. Cadaver allogeneic grafts resulted in low long-term success rate and high prevalence of serious adverse events. Stem Cells Translational Medicine 2019;8:1230&1241.