ABSTRACT
Objective:To investigate the role of nicotinamide (NIC) in the differentiation of neural crest cells from human embryonic stem cells (hESCs), and lay the foundation for the induction of hESC-derived corneal endothelial cells.Methods:hESCs line H1 cultured for 5-7 days was used for induction.According to the different components of the neural crest induction medium, cells were assigned into different groups for 7-days induction, including group treated without NIC cultured in induction medium only, group treated with NIC cultured in induction medium containing 10 mmol/L NIC, NIC+ resveratrol (Res) group cultured in induction medium containing 10 mmol/L NIC and 10 μmol/L Res and Sirtinol group cultured in induction medium containing 10 μmol/L Sirtinol.Res and Sirtinol were used as SIRT1 activity agonist and inhibitor, respectively.The relative mRNA expression levels of hESCs and neural crest cell markers were detected by real-time fluorescence quantitative PCR at 1, 3, 5 and 7 days during the induction.The expression of neural crest cells markers after 7 days of induction was assayed by immunofluorescence staining.The induction efficiency of NIC and the effect of SIRT1 regulation on human natural killer 1 (HNK-1) positive cells expression were evaluated through flow cytometry analysis of percentages of nerve growth factor receptor (P75) and HNK-1 + cells. Results:Compared with the group treated without NIC, the mRNA expressions of totipotent genes octamer transcription factor 4 (OCT4) and homeodomain proteins (NANOG) were significantly decreased, and the mRNA expression levels of neural crest cell markers P75, HNK-1, SRY-related HMG box (SOX) 9 and SOX10 were significantly increased in the group treated with NIC after 5 days of induction (all at P<0.05). In the group treated without NIC, P75 was weakly expressed, and HNK-1 was sporadically expressed, and transcription factor AP-2β (AP-2β) and paired-like homeodomain transcription factor 2 (PITX2) were not detected.In the group treated with NIC, P75, HNK-1, AP-2β and PITX2 were strongly expressed.The proportion of P75 + HNK-1 + cells and P75 + cells were both significantly higher in the group treated with NIC than without NIC ( t=8.481, P=0.001; t=2.987, P=0.041). The percentage of HNK-1 + cells in groups treated without and with NIC, NIC+ Res group and Sirtinol group were (34.267±12.522)%, (89.633±1.358)%, (64.667±6.429)% and (86.300±3.460)%, respectively, with a statistically significant overall difference ( F=36.799, P<0.001). The proportion of HNK-1 + cells in NIC+ Res group was significantly lower than that in the groups treated with NIC and Sirtinol (all at P<0.05). Conclusions:NIC promotes the differentiation of hESCs-derived neural crest cells by inhibiting the activity of SIRT1 to enhance the expression of HNK-1.NIC treatment may provide a new strategy for source of seed cells in the treatment of neural crest cell-related diseases, such as corneal endothelial transplantation.
ABSTRACT
Objective:To investigate the risk factors and treatment outcome of recurrent Acanthamoeba keratitis (AK) after corneal transplantation. Methods:A serial case-observational study was carried out.Twenty-eight eyes of 28 patients with AK who underwent corneal transplantation in Shandong Eye Hospital from January 2012 to January 2019 were enrolled.All the eyes received corneal transplantation from failing to respond to topical and systemic anti- Acanthamoeba medical therapy, including 13 eyes that received penetrating keratoplasty (PKP) and 15 eyes that received lamellar keratoplasty (LKP). The corneal lesion was removed by a trephine with a diameter of 0.5 mm over infiltration area during PKP or LKP.The clinical features of recurrent AK were summarized, including recurrence time, site and signs, and the risk factors of AK recurrence were analyzed.Local and systemic anti- Acanthamoeba medical therapy was performed in all relapsed eyes, and secondary surgery was performed for the eyes with poor response to medication.The therapeutic outcome of recurrent AK was evaluated.The study adhered to the Declaration of Helsinki.This study protocol was approved by an Ethics Committee of Shandong Eye Hospital (No.201112). Results:In the 28 eyes, 7 eyes (25%) appeared recurrent AK after keratoplasty, including 2 eyes after PKP and 5 eyes after LKP.There was no significant difference in the recurrence rate between the two methods ( P=0.396). The recurrence rate of eyes that had used glucocorticoids drugs before operation was 57.14% (4/7), which was significantly higher in comparison with 14.29% (3/21) of eyes without glucocorticoids before surgery ( P=0.043). The recurrence rate of eyes with ulcer diameter ≥8.2 mm was 50.00% (5/10), which was significantly higher than 11.11% (2/18) of eyes with ulcer <8.2 mm ( P=0.036). The recurrent lesions began at the edge of implant bed accounted for 85.71% (6/7), and the recurrent lesions located below graft accounted for 14.29% (1/7). In 7 eyes with recurrent AK, 6 eyes were completely cured.Among recurrent AK eyes after LKP, 2 eyes were cured by long-term medical therapy, and 2 eyes were cured by extended-diameter LKP, and another 1 eye was cured by conjunctival flap covering surgery.One eye with recurrent AK after PKP was cured by extended-diameter PKP. Conclusions:The risk factors of recurrent AK after surgery are application of glucocorticoids before surgery and big lesions.Recurrent AK after surgery is curable by individualized therapy targeting to different clinical characteristics.