Effectiveness and Safety of Trabeculectomy along with Amniotic Membrane Transplantation on Glaucoma: A Systematic Review

Plasma rich in growth factors (PRGF) technology as adjuvant to Ab Externo trabeculectomy

PURPOSE

Plasma rich in growth factors (PRGF) technology creates blood-derived products with growth factors that promote wound healing and regeneration. The goal of this study was to assess the potential role of PRGF products as wound modulators in trabeculectomy. Our premise is that due to PRGF's regenerative and antifibrotic properties, its use in trabeculectomy may produce a more physiological bleb, without altering IOP reduction.

METHODS

A retrospective, longitudinal study was conducted in a Hospital in Portugal. Patients with eyes with open angle glaucoma were included. Trabeculectomy was performed on all patients using PRGF membrane (mPRGF) under the conjunctiva, as adjuvant. Data regarding patients' demographics and number of medications used, was collected. Intraocular pressure (IOP) before surgery, 8 days, 1 month, 3 month, 6 month, 9 month and 1 year after surgery was recorded. Bleb morphology was classified according to Moorfields Bleb Grading System 6 months after surgery.

RESULTS

Nine eyes of 9 patients were enrolled. Mean age was 71 ± 5.1 years old. Six were male. Mean IOP decreased from 24.0 ± 8.8 mmHg pre-surgery to 12.9 ± 2.6 mmHg at one year follow-up. The number of hypotensive drugs (mean ± SD) was 4.3 ± 0.9 preoperatively and 0.8 ± 1.1 at 1-year. Complete success was defined as IOP equal to or less than 21 mm Hg without ocular hypotensive medications and qualified success as IOP equal to or less than 21 mm Hg with medications. Complete success was 66.7% and qualified success was 100% at 1 year follow-up.

CONCLUSION

In our study, trabeculectomy with mPRGF demonstrated both safety and efficacy. Low values of bleb height (1.6 ± 0.8) were recorded. mPRGF could improve wound healing and produce a more well-tolerated, favourable bleb, avoiding antimetabolite complications.

Management of experimental trabeculectomy filtering blebs via crosslinking of the scleral flap inhibited vascularization

PURPOSE

The aim of this study was to evaluate whether UVA-light-activated riboflavin-induced collagen crosslinking (UVA-CXL) can maintain the function of filtering blebs after trabeculectomy (TRAB) in rabbits.

METHODS

Thirty-six healthy rabbits were randomized to one of the following groups with 12 rabbits in each group: Trabeculectomy group (TRAB group), trabeculectomy combined with CXL group (CXL group), and trabeculectomy combined with MMC group (MMC group). Six rabbits of each group were performed with intraocular pressure (IOP), optical coherence tomography (OCT), and OCT angiography (OCTA). Bleb structure was observed via hematoxylin & eosin (H&E) and Masson staining. Immunohistochemistry, proteomic study, western blot, and tensile test were performed between CXL group and the control. In vitro, cell viability was evaluated by CCK-8 and Calcein/PI staining. TRPV4 and VEGF-a expression levels were measured by Q-PCR. Ca2+ concentration was observed with Fluo-4 AM.

RESULTS

The IOP and bleb median survival day were significantly modified in CXL (5.92 ± 0.32 mmHg and 15.5 days) than TRAB group (7.50 ± 0.43 mmHg and 9 days). The bleb area and height increased. CXL inhibited vascularization, and vascularization peaked at postoperative day (POD) 14 and then decreased gradually. In proteomic analyses, Z disc, actin filament binding, and sarcomere organization were significantly enriched. CXL inhibited scleral stress‒strain in tensile tests. Compared with TRAB group, TRPV4 expression was significantly increased, but VEGF-a and TGF-β1 levels were reduced in the CXL group in western blot. Meanwhile, TRPV4 expression colocalized with CD31. In vitro, CXL inhibited HUVECs cell viability. After CXL, expression level of TRPV4 was increased and calcium influx was activated, but VEGF-a was decreased in HUVECs.

CONCLUSIONS

This study demonstrates that intraoperative UV-RF CXL can significantly improve the success rate of TRAB via inhibiting filtering bleb vascularization. CXL increased sclera stiffness, in turn, induced TRPV4 activation, thus contributing to vascular endothelial cells suppression.

Amniotic membrane transplantation: structural and biological properties, tissue preparation, application and clinical indications

The amniotic membrane is a single epithelial layer of the placenta. It has anti-inflammatory, anti-scarring, anti-angiogenic and possibly bactericidal properties. The basement membrane of the amniotic membrane acts as a substrate to encourage healing and re-epithelialisation. It has been used in many ocular surface diseases including persistent epithelial defects (corneal or conjunctival), chemical or thermal burns, limbal stem cell deficiency, cicatrising conjunctivitis, ocular graft versus host disease, microbial keratitis, corneal perforation, bullous keratopathy, dry eye disease, corneal haze following refractive surgery and cross-linking, band keratopathy, ocular surface neoplasia, pterygium surgery, and ligneous conjunctivitis. This review provides an up-to-date overview of amniotic membrane transplantation including the structural and biological properties, preparation and application, clinical indications, and commercially available products.

Plasma Rich in Growth Factors as an Adjuvant Agent in Non-Penetrating Deep Sclerectomy

BACKGROUND

The purpose of this study is to evaluate the utility and safety of plasma rich in growth factors immunosafe eye drops (is-ePRGF) in the postoperative treatment of non-penetrating deep sclerectomy (NPDS).

METHODS

This is a case-control study in patients with open-angle glaucoma. Group one (control) was not treated with is-ePRGF, while group two (is-ePRGF) was treated (four times a day for four months). Postoperative evaluations were performed at one day, one month, three months and six months. The main outcomes were: intraocular pressure (IOP), microcysts in blebs with AS-OCT and the number of hypotensive eye drops.

RESULTS

Preoperatively, group one (n = 48 eyes) and group two (n = 47 eyes) were similar in age (71.5 ± 10.7 vs. 70.9 ± 10.0 years; p = 0.68), IOP (20.6 ± 10.2 vs. 23.0 ± 9.0 mmHg; p = 0.26) and number of hypotensive drugs (2.7 ± 0.8 vs. 2.8 ± 0.9; p = 0.40). The IOP at six months dropped to 15.0 ± 8.0 mmHg (IOP reduction: -27.2%) and 10.9 ± 4.3 mmHg (IOP reduction: -52.6%) for group one and group two, respectively (p < 0.01). At six months, blebs with microcysts were 62.5% (group one) and 76.7% (group two). Postoperative complications were observed in 12 eyes (25%) for group one and in 5 eyes (11%) for group two (p = 0.06). No specific complications related to the use of is-ePRGF were identified.

CONCLUSIONS

Topical is-ePRGF seems to reduce IOP and the rate of complications in the medium term after NPDS, so it can be considered as a possible safe adjuvant to achieve surgical success.

The developments in amniotic membrane transplantation in glaucoma and vitreoretinal procedures

The main reasons why Amniotic Membrane (AM) is transplanted in Ophthalmology are: to provide a substrate for cellular growth and to provide tectonic support or as a biological bandage and barrier that protects the wound to facilitate an environment for wound healing. The application of AM is well-documented in corneal disorders of various aetiologies [1], however, research within the field has highlighted how it can be used in conjunctival disorders and most recently, in glaucoma and vitreoretinal procedures. This review explores the preservation modalities of AM and summarises the current literature regarding AM transplantation in Glaucoma and Vitreoretinal conditions. AM transplantation in conjunction with trabeculectomy was reported to be used in two different surgical techniques. They differ in relation to the position of the implant: below the scleral flap or over the entire exposed sclera. The results of these studies suggest that AM transplant is a safe procedure that helps in the improvement of the intraocular pressure when associated with trabeculectomies. Moreover, it enhances trabeculectomies success rates when used along with mitomycin C [2]. The use of AM is also described for managing leaking blebs. It is mentioned to be a suitable alternative to conjunctival advancement. Regarding AM transplantation in glaucoma shunt or valve surgeries, the current literature is relatively limited. However, AM has been described as a good tectonic support for shunt procedures [3]. Successful results are described in the literature for surgical treatments using AM plug for vitreoretinal procedures. In particular macular hole closure and rhegmatogenous retinal detachment. In conclusion, AM transplant is a very promising and versatile adjutant therapy. However, further studies are also required for a better understanding and refinement of surgical techniques.

The Effect of Amniotic Membrane Transplantation on Trabeculectomy in Patients with Pseudoexfoliation Glaucoma

Purpose

The aim is to evaluate the effect of amniotic membrane transplantation (AMT) on trabeculectomy with mitomycin C in patients with pseudoexfoliation glaucoma (PXG).

Methods

This retrospective cohort study included 85 eyes of PXG who underwent trabeculectomy with or without AMT (52/33 eyes in the AMT/control group). Surgical success was defined by these criteria: (1) intraocular pressure (IOP) ≤18 mmHg and IOP reduction ≥20% and (2) IOP ≤15 mmHg and IOP reduction ≥25%. Criteria A and B defined complete success rates as patients who met these criteria without medication, respectively. Criteria C and D defined qualified success rates as patients who met these criteria with medication, respectively. Cumulative probabilities of success were compared using the Kaplan–Meier survival analysis. Cox proportional hazard models were used to evaluate the influence of AMT on surgical success accounting for confounding variables.

Results

For the AMT group, compared with the control group, the complete success rates at 12 months for criterion A were 86.5% and 63.6%, respectively (P = 0.017) and for criterion B, 86.4% and 63.6% (P = 0.005). The qualified success rates at 12 months for criterion C were 92.1% and 75.1%, respectively (P = 0.047) and for criterion D, 92.1% and 72.1% (P = 0.021). On multivariable Cox regression analyses, AMT was associated with a lower failure rate on criteria A, B, and D (all P ≤ 0.047). Incidence of avascular bleb was higher in the control group than in the AMT group (7 vs 0 eyes; P = 0.004).

Conclusions

In patients with PXG, trabeculectomy with AMT was associated with higher success rates and a lower incidence of avascular bleb compared with conventional trabeculectomy. Research Registration. This retrospective cohort study was registered at the Clinical Trial Registry of Korea (https://cris.nih.go.kr/cris/index/index.do, KCT0007228).