Recurrent pterygium treatment using mitomycin C, double amniotic membrane transplantation, and a large conjunctival flap

A proposed model of xeno-keratoplasty using 3D printing and decellularization

Corneal opacity is a leading cause of vision impairment and suffering worldwide. Transplantation can effectively restore vision and reduce chronic discomfort. However, there is a considerable shortage of viable corneal graft tissues. Tissue engineering may address this issue by advancing xeno-keratoplasty as a viable alternative to conventional keratoplasty. In particular, livestock decellularization strategies offer the potential to generate bioartificial ocular prosthetics in sufficient supply to match existing and projected needs. To this end, we have examined the best practices and characterizations that have supported the current state-of-the-art driving preclinical and clinical applications. Identifying the challenges that delimit activities to supplement the donor corneal pool derived from acellular scaffolds allowed us to hypothesize a model for keratoprosthesis applications derived from livestock combining 3D printing and decellularization.

Sandwich (Amnion/Conjunctival-Limbal Autograft/Amnion) Transplantation for Recurrent Pterygium with Restrictive Strabismus

(1) Background: This study aimed to evaluate the clinical outcome of Sandwich (Amnion/Conjunctival-Limbal Autograft/Amnion) transplantation for recurrent pterygium with restrictive strabismus. (2) Methods: This retrospective study included 11 eyes in 11 patients diagnosed with recurrent pterygium with restrictive strabismus who received sandwich transplantation. The outcomes were measured by pterygium recurrence, best-corrected visual acuity, esotropia (prism diopters), and treatment complications. (3) Results: Eleven patients (six males, five females) had a mean age of 60.5 (range 36-80) years. The previously received pterygium excision surgery number was 1.8 ± 1.02 (range 1-4). The mean follow-up period was 19.9 ± 8.41 (range 12-36) months. All patients had a restriction of abduction in the previously operated eye, causing esotropia in the primary position. Pre-operative esotropia was 17.2 (range 10-30) prims diopter (PD). Five eyes (45.5%) had symblepharon before surgery. All patients were orthotropic until the last follow-up. Symblepharon was released in all eyes. Free ocular motility was present in all eyes. No donor site scar formation, scleral melt, or corneal ulcer was noted. (4) Conclusions: Sandwich transplantation for recurrent pterygium with restrictive strabismus is safe and effective.

Rapid 3D bioprinting of a multicellular model recapitulating pterygium microenvironment

Pterygium is an ocular surface disorder with high prevalence that can lead to vision impairment. As a pathological outgrowth of conjunctiva, pterygium involves neovascularization and chronic inflammation. Here, we developed a 3D multicellular in vitro pterygium model using a digital light processing (DLP)-based 3D bioprinting platform with human conjunctival stem cells (hCjSCs). A novel feeder-free culture system was adopted and efficiently expanded the primary hCjSCs with homogeneity, stemness and differentiation potency. The DLP-based 3D bioprinting method was able to fabricate hydrogel scaffolds that support the viability and biological integrity of the encapsulated hCjSCs. The bioprinted 3D pterygium model consisted of hCjSCs, immune cells, and vascular cells to recapitulate the disease microenvironment. Transcriptomic analysis using RNA sequencing (RNA-seq) identified a distinct profile correlated to inflammation response, angiogenesis, and epithelial mesenchymal transition in the bioprinted 3D pterygium model. In addition, the pterygium signatures and disease relevance of the bioprinted model were validated with the public RNA-seq data from patient-derived pterygium tissues. By integrating the stem cell technology with 3D bioprinting, this is the first reported 3D in vitro disease model for pterygium that can be utilized for future studies towards personalized medicine and drug screening.

Pterygium surgery by double-sliding flaps procedure: Comparison between primary and recurrent pterygia

Purpose

This study aimed to evaluate the surgical outcomes of pterygial excision for primary and recurrent pterygia by a single method of pterygia excision combined with two conjunctival flaps.

Methods

This retrospective study divided 193 cases of pterygium into the primary (140 cases) and recurrent (53 cases) pterygium groups. Following double-sliding conjunctival transposition flap operation and surgical excision of the pterygium, the success and recurrence rates of pterygial surgery were assessed based on visual acuity and corneal and total astigmatism during follow-up at least 6 months.

Results

Both primary and recurrent pterygium groups showed significant improvements in visual acuity and astigmatism (corneal and total) between before and after this procedure. Total astigmatism and success rate of primary pterygium were significantly better than those for recurrent pterygium. Two cases (1.4%) of primary pterygium and four cases (7.5%) of recurrent pterygium developed recurrence, corresponding to a rate of 3.1% (6/193 cases). The success rates significantly make a difference between primary and recurrent groups but did not differ significantly between the first recurrent and over twice recurrent pterygium. However, visual acuity, cornea, and total astigmatism improved significantly after surgery in first recurrent group but not in over twice recurrent group.

Conclusion

The double-sliding conjunctival flaps surgery appeared to be a useful method, with a better success rate and lower pterygial recurrence in pterygium surgery. Especially, when pterygium is larger or recurrent type, this technique can be easily covered the bare sclera, as compared to any transposition conjunctival flap operation.

Recurrent pterygium: A review

Purpose:

To summarize the recent evidence regarding different aspects of pterygium recurrence.

Methods:

Human-based studies from PubMed, Scopus, and Google Scholar were identified using the following keywords: conjunctival disease, pterygium, recurrent pterygium, pterygium recurrence, pterygium management/surgery, conjunctival autograft (CAU), amniotic membrane graft/transplant, and adjuvant therapy (January 2009 to February 2021). We reviewed risk factors associated with the recurrence of pterygium, timing of recurrence, medical treatments to prevent from recurrence, and nonsurgical and surgical alternatives for management of recurrence.

Results:

Dry eye disease, black race, and young age are considered definite risk factors for recurrence. However, fleshy appearance of the pterygium and preoperative size remain controversial. Surgical techniques such as excessive suturing, insufficient conjunctival graft size, thick conjunctival graft with remained Tenon tissue, and postoperative graft retraction are considered possible risk factors for recurrence. Using fibrin glue instead of sutures can further reduce recurrence rates. Although recurrence could occur even after many years, most recurrences happen in the first 3–6 months after surgery. Multiple kinds of adjuvant medications are used before, during, or after the operation including mitomycin C (MMC), 5-fluorouracil (5-FU), corticosteroids, and anti-vascular endothelial growth factors (anti-VEGFs). Multiple weekly subconjunctival 5-FU injections are shown to be safe and effective in halting the progression of recurrent pterygium. Although topical bevacizumab is found to inhibit the growth of impending recurrent pterygium, the effect is mostly temporary. CAU is superior to amniotic membrane transplantation in the treatment for recurrent pterygia.

Conclusions:

There is yet to be a panacea in treating recurrent pterygium. Currently, there is not a globally accepted recommendation for treating recurrent pterygium with anti-VEGFs or 5-FU as a nonsurgical treatment. We strongly recommend using MMC as an adjunct to surgery in recurrent cases, with consideration of its specific complications. CAU is the most effective surgical treatment for recurrent pterygium, and other new surgical therapies need further investigation.

Management of Recurrent Pterygium with Severe Symblepharon Using Mitomycin C, Double Amniotic Membrane Transplantation, Cryopreserved Limbal Allograft, and a Conjunctival Flap

Purpose

The aim of this study was to evaluate the clinical outcomes of management of recurrent pterygium with severe symblepharon using mitomycin C, double amniotic membrane transplantation, cryopreserved limbal allograft, and a conjunctival flap.

Patients and Methods

This retrospective case series included 10 eyes of 10 patients with recurrent pterygium with severe symblepharon. Eight patients have diplopia in primary gaze. All patients underwent pterygium excision, application of mitomycin C (MMC), double amniotic membrane transplantation (AMT), cryopreserved limbal allograft (CLA) transplantation, and placement of a conjunctival flap. Outcome measures were visual acuity, astigmatism, and recurrence. Recurrence was defined as the presence of fibrovascular proliferative tissue crossing the limbus.

Results

The patients’ mean age was 73.8 years. The mean follow-up period was 3.0 years. The mean preoperative and postoperative best-corrected visual acuities (logMAR conversion) were 0.43 and 0.30, respectively. The mean preoperative and postoperative astigmatism were –3.89 diopters and –1.54 diopters, respectively, and there was a significant difference. No recurrence occurred in any of the eyes. Symblepharon was released in all eyes. Diplopia in primary gaze was resolved in all eyes.

Conclusion

Management of recurrent pterygium with severe symblepharon using MMC, double AMT, CLA, and a conjunctival flap was an effective treatment.

Elevation of S100 calcium-binding protein A7 in recurrent pterygium

Recurrent pterygium, a common ophthalmic disease, is difficult to treat as its pathogenesis is unclear. To investigate the key genes responsible for the recurrence of pterygium, tissue samples were collected from six patients with primary pterygium (primary group), six patients with recurrent pterygium (recurrent group) and six patients with ocular trauma (control group) who underwent surgery between December 2014 and June 2017. The differentially expressed genes amongst these tissues were detected using expression profiling microarrays and verified by reverse transcription-quantitative PCR (RT-qPCR). Comparing the primary and control groups, 10 genes, including PP7080, small proline-rich protein 2A, keratin 24, small proline-rich protein 2F, defensin β4A, serpin family A member 3, S100 calcium-binding protein A7 (S100A7), Fc fragment of IgG binding protein and BPI Fold Containing Family A Member 1, were identified to be consistently upregulated in recurrent pterygium tissues, whilst two genes (H19 imprinted maternally expressed transcript and secretoglobin family 2A member 1) were consistently downregulated. Following RT-qPCR verification, it was identified that that S100A7 gene was significantly upregulated in recurrent pterygium tissues compared with the other groups. Protein-protein interaction and Gene Ontology analysis further revealed that all genes interacting with S100A7 were mainly involved in the regulation of defense mechanisms against bacteria, mitogen-activated protein kinase (MAPK) pathway activation and receptor for advanced glycation end-products receptor binding. The present findings confirmed that elevation of S100A7 expression in recurrent pterygium may be associated with the inflammatory response and activation of the MAPK signaling pathway.