Custom RT-qPCR-array for glaucoma filtering surgery prognosis

Differential Gene and Protein Expression of Conjunctival Bleb Hyperfibrosis in Early Failure of Glaucoma Surgery

The early failure of glaucoma surgery is mainly caused by over-fibrosis at the subconjunctival space, causing obliteration of the filtration bleb. Because fibrosis has a suspected basis of genetic predisposition, we have undertaken a prospective study to identify upregulated profibrotic genes in a population of glaucoma patients with signs of conjunctival fibrosis and early postoperative surgical failure. Clinical data of re-operated fibrosis patients, hyperfibrosis patients who re-operated more than once in a short time, and control patients with no fibrosis were recorded and analyzed at each follow-up visit. Conjunctival-Tenon surgical specimens were obtained intraoperatively to evaluate the local expression of a panel of genes potentially associated with fibrosis. In order to correlate gene expression signatures with protein levels, we quantified secreted proteins in primary cultures of fibroblasts from patients. Expression of VEGFA, CXCL8, MYC, and CDKN1A was induced in the conjunctiva of hyperfibrosis patients. VEGFA and IL8 protein levels were also increased in fibroblast supernatants. We propose that an increase in these proteins could be useful in detecting conjunctival fibrosis in glaucoma patients undergoing filtering surgery. Molecular markers could be crucial for early detection of patients at high risk of failure of filtration surgery, leading to more optimal and personalized treatments.

Silencing of p53 reduces cell migration in human Tenon's fibroblasts induced by TGF-β

PURPOSE

Growth factors are considered as key molecules that participating in fibrosis formation. This research aimed to clarify potential effects of p53 on regulation of transforming growth factor β (TGF-β) and fibrosis formation and investigate the associated mechanisms.

METHODS

Vimentin was examined to identify human Tenon's fibroblasts (HTFs). p53-targeting small interfere RNA (siRNA) was synthesis and transfected into HTFs. Real-time PCR assay was utilized to evaluate p53 and microRNA-29b (miR-29b) expression. Immunocytochemical assay was used to observe TGF-β expression. The wound healing assay was conducted to evaluate migration of HTFs. Dual-luciferase assay was employed to identify interaction between p53 and miR-29b in HTFs.

RESULTS

Vimentin was extensively distributed in HTFs cells. HTFs at density of 5 × 10⁴ cells/ml and 6 days exhibited the best growth. The p53 level in TGF-β treatment group was significantly higher compared to that in blank group (p < 0.01). miR-29b level in siRNA targeting p53 group was significantly increased compared to that in blank group (p < 0.01). siRNA targeting p53 could significantly inhibit HTFs migration compared to that in single TGF-β treating HTFs group (p < 0.01). Relative luciferase activity was significantly increased in p53 overexpressed HTFs compared to that in cells transfected with empty pcDNA3.0 plasmid (p < 0.01).

CONCLUSIONS

p53 inhibited expression of TGF-β, suppressed HTFs migration and inhibited HTFs growth, by reducing miR-29b expression and interacting with miR29b gene in HTFs.

[Anti-scarring effect of rapamycin in rabbits following glaucoma filtering surgery]

OBJECTIVE

To study the anti- scarring effect of rapamycin in rabbits receiving glaucoma filtering surgery.

METHODS

Ninety-six Chinchilla rabbits were randomized equally into 3 rapamycin treatment groups and one control group. All the rabbits underwent trabeculectomy, after which the rabbits in the 3 rapamycin groups were treated with eye drops containing 1%, 3%, or 5% rapamycin in the operated eyes, and those in the control groups were given castor oil 4 times a day. The intraocular pressure (IOP) and inflammatory reaction in the treated eyes were observed, and the PCNA-positive cells in the filtering bleb were detected using immunohistochemistry. RTFs isolated from the Tenon's capsule of the rabbits were cultured in vitro, and the expressions of caspase-3, caspase-8, and caspase-9 in the fibroblasts were detected after treatment with different concentrations of rapamycin.

RESULTS

The IOP was significantly lower in rapamycin-treated group than in the control group after the surgery (P < 0.05). The counts of the PCNA-positive cells were significantly lower in rapamycin-treated rabbits than in the control group (P < 0.05). Rapamycin treatment dose-dependently increased the expressions of caspase-3 and caspase- 9 at both the mRNA (P < 0.001) and protein (P < 0.001) levels without causing significant changes in the expressions of caspase-8.

CONCLUSIONS

Rapamycin can inhibit excessive proliferation of the fibroblasts in the filtering bleb to reduce scar formation after glaucoma filtration surgery in rabbits. Rapamycin also increases the expressions of caspase-3 and caspase-9 to induce apoptosis of the RTFs.