Mesenchymal stem cells in corneal neovascularization: Comparison of different application routes

Abstract

The purpose of the present study is to investigate the effect of mesenchymal stem cells in corneal neovascularization and wound healing, and to compare the effectiveness of two possible application routes, subconjunctival injection and amniotic membrane transplantation. Chemical injury was induced by application of sodium hydroxide to the rats' corneas. After 7 days, the animals were divided into three groups. Different treatment methods were used for each group as follows: i) Group 1, injection of bone marrow-derived mesenchymal stem cells (BMSCs) under the conjunctiva; ii) group 2, transplantation of amniotic membranes, previously seeded with BMSCs; and iii) group 3, the untreated control group. The eyes were examined using a slit lamp on a weekly basis. After 4 weeks, the animals were sacrificed and corneas were removed for further examination. Corneal flat mounts were made following ink perfusion for improved vessel visualization, image capturing and quantitative evaluation. enzyme-linked immunosorbent assay was performed to detect the levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP-9). Reverse transcription-quantitative polymerase chain reaction was used for detection of VEGF-A, MMP-9, Toll-like receptor (TLR)2 and TLR4 gene expression levels. Cryosections were used for histological examination and immunostaining. Statistical analysis (Welch's one-way analysis of variance) demonstrated a significant difference between the groups [P≤0.05, confidence interval (CI) 95%]. The level of injury in group 1 was significantly different from groups 2 and 3. Measurement of the vessel area and VEGF gene expression levels had a similar difference among the groups (P≤0.05, CI 95%), however the differences for TLR2 and TLR4 were not statistically significant. BMSCs were previously transduced with the green fluorescent protein gene by lentivirus to track the movement of the cells following transplantation. The transplanted cells enhanced corneal wound healing by trophic factor production and immune-regulatory effect, rather than by direct transdifferentiation into corneal cells. The results of the current study demonstrated that BMSCs enhance corneal wound healing and decrease the area of neovascularization. Furthermore, the comparison of two application routes indicated that single subconjunctival injection appeared more effective than transplantation with amniotic membrane.

The potential therapeutic effect of stem cells loaded on two different vehicles (amniotic membrane and platelet rich plasma gel) in experimentally induced corneal alkali burns in rats

“…Also, edema might increase the interstitial pressure leading to stagnation with incomplete vessel obstruction. The subsequent decrease in corneal oxygenation would delayed wound regeneration and exacerbate the injury [34] .…”

Cellular Reparative Mechanisms of Mesenchymal Stem Cells for Retinal Diseases

“…Among the vast potential of MSCs, substantial pre-clinical and clinical studies have equally validated on the therapeutic potential of MSCs in restoration of ocular neovascularization. In a recent study, subconjunctival injection bone marrow-derived MSCs into chemically-induced rat cornea where was found to encourage corneal wound healing and stabilized neovascularization lesion through suppression of VEGF, Matrix Metalloproteinase 9 (MMP-9), and Toll-Like Receptors (TLRs), which presumably contributes to the downregulation of pro-inflammatory cytokine production [ 108 ]. In an oxygen-induced retinopathy mouse model, intraperitoneal transplantation of human placental amniotic membrane-derived MSCs efficiently homed to and engrafted onto the injured site with profound release of angiogenic factor, Transforming Growth Factor-β1 (TGF-β1) from MSCs [ 54 ].…”

Comparative Light and Electron Microscopic Study on the Therapeutic Efficacy of Adipose Derived Stem Cells Versus Exosomes for Experimentally Induced Acute Corneal Injuries in Rats

“…Many studies explained that MSCs [51,52] act as a good stimulator for angiogenesis and could secrete vascular VEGF in an ischemia or tumor model. However, MSCs appeared to have a contradictory result in corneal angiogenesis.…”

“…However, MSCs appeared to have a contradictory result in corneal angiogenesis. Some in vivo researchers [51,52] found that applying MSCs into the cornea could efficiently inhibit inflammationrelated angiogenesis after induced chemical injury through their capacity to increase the liberation of thrombospondin-1, a powerful anti-angiogenic factor. Also, many inflammation-related proangiogenic factors were significantly reduced after MSCs treatment.…”