组织工程结膜支架的研究进展

结膜重建常用于各种化学热烧伤所导致的严重结膜缺损,而组织工程结膜能有效解决在结膜移植中自体结膜移植材料缺乏及异体结膜移植材料存在免疫排斥反应等难题。具有良好生物相容性及足够生物力学强度的支架材料是构建组织工程结膜的重要条件。本文对组织工程结膜支架材料的最新研究进展及目前存在的问题进行总结。

In vitro tissue engineering of lamellar cornea using human amniotic epithelial cells and rabbit cornea stroma

AIM:To reconstruct the lamellar cornea using human amniotic epithelial(HAE) cells and rabbit cornea stroma in vitro using tissue engineering technology.·METHODS:Human amnia taken from uncomplicated caesarean sections were digested by collagenase to obtain HAE cells,and the cells were cultured to proliferate.Rabbit corneal epithelial cells were removed by n-heptanol to make lamellar matrix sheets.The second passage of HAE cells were cultured on the corneal stroma sheets for 1 or 2 days,then transferred to an air-liquid interface environment to culture for 2weeks.Tissue engineered lamellar cornea(TELC)morphology was observed by Hematoxylin-eosin(HE)staining;its ultrastructure was observed by transmission electron microscopy(TEM) and scanning electron microscopy(SEM);corneal epithelial cell-specific keratin3 and keratin 12 were detected with immunofluorescence microscopy.·RESULTS:HAE cells grew on the rabbit corneal stroma,forming a monolayer after 1-2 days.About 4-5 layers of epithelial cells developed after 2 weeks of air-liquid interface cultivation,a result similar to normal corneal epithelium.Rabbit corneal stromal cells were significantly reduced after one week,then almost completely disappeared after 2 weeks.TEM showed desmosomes between the epithelial cells;hemidesmosomes formed between the epithelial cells and the basement membrane.SEM revealed that the HAE cells which grew on the lamellar cornea had abundant microvilli.The tissue-engineered cornea expressed keratin 3 and keratin 12,as detected by immunofluorescence assay.·CONCLUSION:Functional tissue-engineered lamellar corneal grafts can be constructed in vitro using HAE cells and rabbit corneal stroma.

Effects of resveratrol on ARPE-19 cell proliferation and migration via regulating the expression of proliferating cell nuclear antigen, P21,P27 and p38MAPK/MMP-9

AIM： To explore whether resveratrol （Res） can inhibit human retinal pigment epithelial cell （ARPE-19 cell） proliferation and migration, and to research the molecular mechanisms.METHODS： ARPE-19 cells were pretreated with various concentrations at 0, 50, 100, 150, 200 and 300 μmol/L of Res, and with 0 μmol/L Res as the control for 24, 48 and 72h. The cell proliferation, apoptosis and migration were measured with cell counting kit-8 （CCK-8）, flow cytometry, and wound-healing and Transwell assays, respectively. The expression of proliferating cell nuclear antigen （PCNA）, P21 and P27, as well as matrix metalloproteinase-9 （MMP-9） and p38 mitogen-activated protein kinases （p38MAPK） was identified by Western blot.RESULTS： Cell proliferation was effectively inhibited by Res （P〈0.05）. When pretreated with Res, cells arrested in S-phase increased remarkably （P〈0.05）, but the apoptosis ratios showed no significant difference between the treatment and control groups （P〉0.05）. Cell migration was suppressed by Res both in wound-healing assay and Transwell migration assay （P〈0.05）. Decreases of PCNA, MMP-9 and p38MAPK, as well as increases of P21 and P27 were detected by Western blot （P〈0.05）. CONCLUSION： Res can inhibit APRE-19 cell proliferation and migration in a concentration-dependent manner with up-regulation of the expression of P21 and P27, and down-regulation of PCNA, MMP-9 and p38MAPK.

Bevacizumab versus ranibizumab for neovascular agerelated macular degeneration: a Meta-analysis

AIM: To systematically compare the efficacy and safety of off-label bevacizumab versus licensed ranibizumab intravitreal injections as well as monthly regimen versus pro re nata [PRN(as needed)] regimen in the treatment of neovascular age-related macular degeneration(n AMD).METHODS: Relevant publications were identified through automatically retrieve of database and manually retrieving. The methodological quality of studies included was assessed using the Jadad score and the risk-of-bias assessment. The efficacy estimates were measured by the weight mean difference(WMD) for the improvement of best-corrected visual acuity(BCVA) and central retinal thickness(CRT) reduction. The safety estimates were measured by odds ratios(OR) for adverse events rates. Statistical analysis was conducted by Revman 5.2.7.RESULTS: Seven studies were included in the Metaanalysis. There were no statistically significant differences between bevacizumab and ranibizumab in BCVA at 1 and 2y(P =0.37, P =0.18, respectively),However, both drugs has better BCVA given monthly than given as needed at 1 and 2y(P 【0.05). The results demonstrated the mean decrease in CRT was less in bevacizumab group than ranibizumab group at 1y(P 【0.05),while the difference was not significant at 2y(P =0.24).Treatment monthly gained much more decrease in CRT at 1 and 2y(P 【0.005).There were no differences between drugs in the rates of death, arterial thrombotic events and venous thrombotic events(P =0.41, P =0.55, P =0.10,respectively), while the rates of medical dictionary for regulatory activities(Med DAR) system organ class events and ≥1 systemic serious adverse events were higher in bevacizumab group than ranibizumab group(P 【0.05).But the incidences of death, arterial thrombotic events,venous thrombotic events, Med DAR system organ class events as well as ≥1 systemic serious adverse events were not statistically different between both treatment regimens of monthly and as needed(P =0.14, P =0.76,P =0.73, P =0.12, P =0.11, respectively).· CONCLUSION: Bevacizumab was equivalent to ranibizumab for BCVA, however bevacizumab tended to gain less decrease in CRT and had higher rates of serious adverse events. Compared with treatment as needed, treatment monthly showed superior efficacy in BCVA improvement and CRT reduction, while the rates of adverse events were similar in the two dosing regimens.

Species diversity, updated classification and divergence times of the phylum Mucoromycota

Zygomycetes are phylogenetically early diverging,ecologically diverse,industrially valuable,agriculturally beneficial,and clinically pathogenic fungi.Although new phyla and subphyla have been constantly established to accommodate spe-cific members and a subkingdom Mucoromyceta,comprising Calcarisporiellomycota,Glomeromycota,Mortierellomycota and Mucoromycota,was erected to unite core zygomycetous fungi,phylogenetic relationships within phyla have not been well resolved.Taking account of the information of monophyly and divergence time estimated from ITS and LSU rDNA sequences,the present study updates the classification framework of the phylum Mucoromycota from the class down to the generic rank:three classes,three orders,20 families(including five new families Circinellaceae,Protomycocladaceae,Rhizomucoraceae,Syzygitaceae and Thermomucoraceae)and 64 genera.The taxonomic hierarchy was calibrated with estimated divergence times:phylum earlier than 617 Mya,classes and orders earlier than 547 Mya,families earlier than 199 Mya,and genera earlier than 12 Mya.Along with this outline,all genera of Mucoromycota are annotated and 58 new species are described.In addition,three new combinations are proposed.In this study,we update the taxonomic backbone of the phylum Mucoromycota and reinforce its phylogeny.We also contribute numerous new taxa and enrich the diversity of Mucoromycota.