Investigation Of Human Umbilical Cord Mesenchymal Stem Cells Derived Exosomes In Large Idiopathic Full-thickness Macular Hole

Purpose:In our previous study,we demonstrated that mesenchymal stem cells derived exosomes(MSCs-Exos)could promote neuroregeneration and neural functional recovery in retinal laser damage by inhibition of apoptosis and inflammatory responses.The objective of this research was to observe the safety and efficiency of large idiopathic full-thickness macular hole(FTMH)repaired by 25-gauge pars plana vitrectomy(PPV)combined with internal limiting membrane(ILM)peeling,air tamponade and human umbilical cord mesenchymal stem cells derived exosomes(Huc MSCs-Exos)intravitreal injection.Based on Huc MSCs-Exos characteristics,we hypothesised that Huc MSCs-Exos might contribute to MH closure and visual recovery,which provided theoretical and clinical insight on the treatment for FTMH.Methods:(1)Fresh umbilical cords(UC)were obtained from informed healthy mothers in a local maternity hospital after normal deliveries.Flow cytometry and real timePCR were used to validate the phenotype of cultured Huc MSCs.Huc MSCs were cultured in a conditional media for induced differentiation test.The protein concentration of Huc MSCs-exos was measured by a BCA protein assay kit,scanning electron microscopy was used to observe the morphology of exosomes.Huc MSCs-exos were obtained and showed typical exosomes structure and characterized by protein marker.(2)A prospective randomized controlled trial.Patients with large idiopathic fullthickness macular hole(FTMH)were randomized into control and Huc MSCsExos groups.A diameter≥400 μm defined as large FTMH.Thirty-seven patients(37 eyes)underwent PPV surgery for FTMH in Tianjin Medical University Eye Hospital,with MH diameter exceeding 400 μm were enrolled.All patients underwent a standard 25-G PPV.After core vitrectomy and a posterior vitreous detachment induction if needed using the vitrectomy cutter in the suction mode,a meticulous peripheral vitrectomy with indentation was performed,and internal limiting membrane(ILM)equivalent to 4 papillary diameters were peeled.Eighteen patients were enrolled in control group,the subretinal remnant macular fluid was delicately aspirated after the air-fluid exchange procedure,19 patients were enrolled in Huc MSCs-Exos group,the subretinal remnant macular fluid was delicately aspirated after the air-fluid exchange procedure and 0.02 ml Huc MSCs-Exos intravitreal injection.At the end of the surgery,air was injected into the eye.The intraoperative primary outcome measures were operation time and complications.The patients were instructed to keep a facedown position for 3 days after the operation.Broad-spectrum antibiotic eye drop was routinely given.Postoperative(1,3,6 and 12 months),all patients underwent a complete ocular evaluation,including the best corrected visual acuity(BCVA),dilated fundus examination,color fundus photography,infrared reflectance,and spectral-domain OCT operation,multifocal electroretinogram(mf ERG),general ophthalmic examination,intraocular pressure measurement,and fundus examination without dilation were performed.Results:(1)Huc MSCs were obtained and verified for its differentiation ability,blank calcium salts deposition was found in bone-like cells.(2)Huc MSCs-exos were obtained and showed typical exosomes structure and characterized by protein marker CD9,CD63,CD81 and TSG01.(3)37 eyes of 37 patients were enrolled,including 5 men(13.51%)and 32 women(86.49%),(mean age,60.08±4.62 years;mean follow-up period,11.16 ± 2.13months).All patients were examined at baseline and at 1,3,6 and 12 months after surgery.The preoperative characteristics of the FTMH and their dimensions were evaluated but no statistical difference was noted between control group and Huc MSCs-Exos group.All FTMH were closed after the first surgery with no intraoperative or postoperative complications.In all patients of control group(100%),FTMH closed after the first surgery.The mean BCVA at baseline was 0.62±0.32 log MAR and at 12 months follow-up was 0.27 ± 0.31 log MAR.In group Huc MSCs-Exos(100%),FTMH closed after the first surgery.In this group,the mean BCVA at baseline was 0.68±0.21 log MAR and at the end of the follow-up was 0.23 ± 0.18 log MAR.Postoperative BCVA was noted no statistical difference between two groups.At 1,3,6 months after surgery mf ERG amplitude of P1 in ring 1 and at 1 and 3 months after surgery mf ERG amplitude of P1 in ring 2 for group Huc MSCs-Exos were significantly better than in control groupConclusion:The results indicate that Huc MSCs-Exos therapy could be an useful and safe method in improving the anatomic and visual outcomes of surgery for FTMH.