Novel amniotic membrane: A step ahead of other scaffolds for pterygia

This article was reviewed by Vicente A. Diaz, MD, MBA

A novel amniotic membrane product, Biovance 3L Ocular (Celularity), seems highly promising for its role in ocular regenerative procedures, according to Vicente A. Diaz, MD, MBA, an assistant professor of clinical ophthalmology at Yale School of Medicine in New Haven, Connecticut.

Diaz explained that in contrast to other available products, such as Ambio2 (Katena Products) and AmnioGraft (BioTissue), Biovance 3L has a few characteristics that set it apart. One is that it is a 3-layer dehydrated membrane comprised solely of amniotic tissue, and the basement membrane is intact; in addition, the decellularization process removes any residual cells, cellular debris, DNA, growth factors, and cytokines. These characteristics promote rapid cellular attachment within hours, and the attachment stimulates the release of growth factors and cytokines.

The use of amniotic membrane has been indicated for treating numerous ocular diseases. These include pterygium, keratitis, more advanced dry eye, recurrent corneal erosions, filamentary keratitis, persistent epithelial defects, neurotrophic corneas, herpetic ulcers, chemical burns, and Stevens-Johnson syndrome.

Amniotic membrane bench study

Diaz and colleagues conducted a study to evaluate the performance of Biovance 3L regarding human ocular epithelial cell adhesion, viability proliferation, and migration compared with those parameters when using Ambio2and AmnioGraft.

In this study, to ascertain the therapeutic potential of Biovance, the investigators evaluated human corneal epithelial cells (HCECs) and human conjunctival epithelial cells for their adhesive and proliferative capabilities on days 1, 4, and 7 after the cells were seeded onto scaffolds and incubated for 24 hours. Conditioned media were extracted from cells grown on scaffolds and used for cell migration assays, Diaz noted.

The results showed that at 24 hours after seeding, the HCEC viability, which represents adhesion, was significantly (P < .011) greater with Biovance 3L than with the other scaffolds; the HCEC proliferation with Biovance was significantly (P < .001) greater than that of AmnioGraft and human conjunctival epithelial cells at all time points. The effects of conditioned media on the migration of the HCECs were similar between Biovance and Ambio2 (P = .885) and significantly (P≤ .006) greater than with AmnioGraft.

“Biovance 3L had a significant effect on human epithelial cells by supporting greater viability adhesion and proliferation compared with other scaffolds,” Diaz noted. “Further research is needed to assess the clinical impact of these findings.

Addressing pterygium

The current treatment for pterygia is surgical excision, and the approaches to wound healing include autografts, bare sclera, simple closure, and use of amniotic membrane. This last approach, amniotic membrane, is associated with the lowest pterygia recurrence rates (2%-14%) compared with rates ranging from 5% to 82% for the other options. At present, amniotic membranes are fixed in the eye using sutures, fibrin glue, autologous serum, and hydrostatic force, all of which are associated with long surgical times and prolonged patient discomfort; additionally, fibrin glue is expensive.

Diaz and colleagues evaluated the effects of a novel sutureless and glueless surgical technique using the triple-layer dehydrated amniotic membrane for excise pterygia. They investigated the surgical time required and the postoperative pain, epiphora, irritation, and foreign body sensation associated with the procedure.

The investigators compared their results with those obtained in other studies in which autologous serum, sutures, or fibrin glue were used. Diaz’s study group comprised 20 eyes of 18 patients. The surgical time was defined as starting at the time of the lidocaine injection and ending when a bandage contact lens was placed on the eye.

All patients completed a questionnaire to record symptoms, which were measured using a 5-point scale of pain, epiphora, irritation, and foreign body sensations. The measurements were recorded on postoperative day 1, postoperative week 1, and postoperative month 1.

The authors reported that the surgical time was a mean of 8.29 minutes in contrast to 20.4 minutes in a study of conjunctival autografting,1 a difference of 11.9 minutes that reached significance (P < .0001).

Regarding questionnaire scores, at postoperative day 1, the respective scores for pain, foreign body sensation, irritation, and epiphora were 1.8, 2.3, 1.0, and 2.6; on postoperative week 1, the respective scores were 1.5, 1.6, 1.6, and 1.6.

Diaz noted that compared with results from previous studies,1-3 this technique showed significantly improved pain for all parameters on postoperative day 1 (P = .0086, P < .0001, P < .0001, P < .0001) and at postoperative week 1 (P = .0354, P= .0002, P = .0016, P < .0001). The foreign body sensation also improved at postoperative day 1 when compared with fibrin glue (P = .0321) or sutured techniques (P < .0001).

“The sutureless, glueless technique using Biovance 3L is a safe and effective surgical technique compared [with] current standard methods,” Diaz concluded. “There appears to be a significant benefit regarding surgical time and postoperative pain, irritation, epiphora, and foreign body sensation compared [with that of] previous studies.”

Vicente A. Diaz, MD, MBA

E: vicente.diaz@yale.edu

Diaz is an assistant professor of clinical ophthalmology at Yale School of Medicine in New Haven, Connecticut. He is a paid consultant to Celularity.

References

1. Xu F, Li M, Yan Y, Lu K, Cui L, Chen Q. A novel technique of sutureless and glueless conjunctival autografting in pterygium surgery by electrocautery pen. Cornea. 2013;32(3):290-295. doi:10.1097/ICO.0b013e31824f8c15

2. Donepudi GD, Ramesh S, Govindarajulu M, et al. Early postoperative outcomes of pterygium surgery: sutures versus autogenous serum in-situ fixation of limbal conjunctival autograft. Life Sci. 2019;221:93-98. doi:10.1016/j.lfs.2019.02.019

3. Kucukerdonmez C, Karalezli A, Akova YA, Borazan M. Amniotic membrane transplantation using fibrin glue in pterygium surgery: a comparative randomised clinical trial. Eye (Lond). 2010;24(4):558-566. doi:10.1038/eye.2009.136