Research Article: Custom RT-qPCR-array for glaucoma filtering surgery prognosis

Date Published: March 30, 2017

Publisher: Public Library of Science

Author(s): Iñaki Rodriguez-Agirretxe, Iker Garcia, Javier Soria, Tatiana Maria Suarez, Arantxa Acera, Sanjoy Bhattacharya.


Excessive subconjunctival scarring is the main reason of failure of glaucoma filtration surgery. We analyzed conjunctival and systemic gene expression patterns after non penetrating deep sclerectomy (NPDS). To find expression patterns related to surgical failure and their correlation with the clinical outcomes. This study consisted of two consecutive stages. The first was a prospective analysis of wound-healing gene expression profile of six patients after NPDS. Conjunctival samples and peripheral blood samples were collected before and 15, 90,180, and 360 days after surgery. In the second stage, we conducted a retrospective analysis correlating the late conjunctival gene expression and the outcome of the NPDS for 11 patients. We developed a RT-qPCR Array for 88 key genes associated to wound healing. RT-qPCR Array analysis of conjunctiva samples showed statistically significant differences in 29/88 genes in the early stages after surgery, 20/88 genes between 90 and 180 days after surgery, and only 2/88 genes one year after surgery. In the blood samples, the most important changes occurred in 12/88 genes in the first 15 days after surgery. Correspondence analyses (COA) revealed significant differences between the expression of 20/88 genes in patients with surgical success and failure one year after surgery. Different expression patterns of mediators of the bleb wound healing were identified. Examination of such patterns might be used in surgery prognosis. RT-qPCR Array provides a powerful tool for investigation of differential gene expression wound healing after glaucoma surgery.

Partial Text

Glaucoma is characterized by progressive deterioration of retinal nerve fiber layer and optic nerve, leading to defects in the visual field and optic atrophy. In most cases, the condition is associated with increased intraocular pressure (IOP) caused by obstruction of drainage of aqueous humor from the eye. Currently, the main treatment for glaucoma is reduction of IOP using drugs and laser or filtration surgery.

None of the patients had intraoperative or postoperative complications. Regarding to the existence of systemic diseases, two patients were hypertensive patients treated with angiotensin-converting-enzyme inhibitors (ACE inhibitors), one patient suffered hypothyroidism treated by hormone replacement therapy and two patients were taking gastric protector. Finally, one patient was non-insulin dependent diabetic and was being treated with oral antidiabetic drugs.

Despite the downward trend in glaucoma surgery since the nineteen-nineties [14], it is still a procedure with major advantages; it is inexpensive [15] and allows an IOP reduction more drastic [16] and less fluctuating than pharmacological treatment [17]. Although the most common glaucoma surgical technique worldwide is the trabeculectomy, some alternative interventions have been proposed to reduce the IOP. The NPDS could be considered as a variation of the trabeculectomy which does not require iridectomy and allows the aqueous humor to drain gradually, reducing IOP in a less abrupt manner. Long-term results seem to be not worse than those of trabeculectomy [18]. However, subconjunctival and episcleral scarring remain the main impediment to the long-term success of any filtering surgery [19], irrespective of whether it is perforating or non-perforating procedure [20].




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