Investigation of Therapeutic Efficacy and Safety of UMSCs for the Management of Retinitis Pigmentosa (RP)

Isolation and characterization of human umbilical cord derived mesenchymal stem cells (UMSCs): The culturing and characterization of UMSCs will be performed as documented by Ali and colleagues. Briefly, human umbilical cord tissues along with informed consent forms will be collected from COVID-19- and hepatitis B, C virus-negative women with healthy pregnancies during the Cesarean Section surgery after completion of gestation period. The umbilical cord tissue will be transported in sterile 1x phosphate-buffered saline (PBS) containing penicillin and streptomycin on ice. In the biosafety cabinet, the cord will be washed with 4-5 changes of sterile 1x PBS and placed in a Petri plate with 15ml PBS. The cord will then gently scrap with a surgical blade to remove any dead cells. A 9 cm umbilical cord will be cut into three equal pieces and wash thoroughly to remove blood clots, umbilical cord arteries, and veins. Segments will be washed three times with PBS and minced. The minced pieces will be incubated in 17.5ml of collagenase solution (201 U/ml collagenase type I in serum-free DMEM-HG) in a 50ml conical tube for \~3 hrs in an incubator at 5% CO2, 95% humidity at 37oC. After \~3 hrs, the digested lysate will be passed through strainer and will be diluted three times with 1x PBS. Following centrifugation, the cells will be seeded into two T-25cm2 flasks and will be placed in an incubator at 5% CO2, 95% humidity at 37o C. The flasks will be fed with fresh media (DMEM-HG supplemented with 20% FBS and 1% antibiotic solution) every third day. At around day 18, cells will reach up to 85% confluency and will be transferred in two T-75cm2 flasks with media replaced at alternate days. UMSCs at P3 will be characterized using different specific antibodies. Cells at P3 will be employed for injection in RP patients.