Eyeworld

WINTER 2025 | EYEWORLD | 61 C by Ellen Stodola Editorial Co-Director About the physicians Neel Desai, MD The Eye Institute of West Florida Tampa, Florida John Hovanesian, MD Harvard Eye Associates Laguna Hills, California OPENING DOORS A mniotic membrane products can be a valuable tool to help open doors in the treatment of corneal diseas- es. These products can aid in the treatment of a variety of diseases and can be added to other treatments to help patients find relief. Neel Desai, MD, and John Hovanesian, MD, discussed the different types of products available and best applications. Dr. Hovanesian has been using amniotic membranes for more than 25 years, since before they were widely commercially available. "Early on, there was a division between the methods of preparing the membrane; one is to freeze, and one is to dehydrate it," he said. "Both pro- vide viable surgical products; both are equally valuable in my mind as methods of restoring a healthy ocular surface. I think the difference really comes down to what form factor suits the surgeon and application in the patient." Dr. Desai agreed that historically, we've dis- tinguished amniotic membrane products based on the preservation process. The cryopreserved category is overwhelmingly represented by Bio- Tissue products with their proprietary cryopres- ervation process that preserves all layers of the amnion as well as HC-HA/PTX3, a high molecu- lar weight complex that provides an initial boost of anti-inflammatory and pro-healing effects. In contrast, dehydrated membrane products used to be lumped together. "But in the last year or so, I've come to realize that's not a fair lens to view the world in anymore," Dr. Desai said, noting the introduction of a decellular- ized, multi-layer amniotic membrane product, Biovance 3L Ocular (DefEYE). With conven- tional dehydrated membrane, he said, there are numerous options, and these membranes are typically dehydrated in a heat-based process to make them more efficient in terms of time and cost. The Biovance 3L Ocular decellularized basement membrane is processed without heat, which preserves key extracellular matrix pro- teins and cytokines that promote healing. Whereas both cryopreserved membrane and conventional dehydrated membranes retain all cellular layers of the donor amnion and some chorionic cells (which are quite inflammatory), the Biovance 3L Ocular product uniquely re- moves all pro-inflammatory cellular debris and only retains the most beneficial bioactive layer of the amnion—the basement membrane. After placement of a cryopreserved mem- brane, the recipient's healing process can only proceed as fast as the amniotic membrane scaffold is cleared by macrophages and other phagocytic cells. These cells remove donor cellular debris and apoptotic cells that were retained in the cryopreservation process. Any impaired efferocytosis or dysregulated apoptosis can incite inflammation and delay healing. As a decellularized, multi-layer basement membrane, Biovance 3L Ocular does not require cellular clearance and does not carry the same risk of inflammation and delay in healing, Dr. Desai said. This has been shown to produce better cellular viability and adherence, which triggers higher concentrations of both growth factors and anti-inflammatory cytokines that result in profound clinical implications for wound heal- ing, he said. Dr. Desai's experience with these products has changed his view on the biological science, the wound healing process, and the clinical results with these products. "I think that based on these more clinically relevant factors, de- cellularized, multi-layer basement membrane creates and deserves its own category because it's unique from both cryopreserved and conven- tional dehydrated membranes," he said. Dr. Desai equates the effect of the HC-HA/ PTX3 in cryopreserved membranes to having fertilizer in the soil where you want your seeds to thrive. These biological factors eventually be- come exhausted and the recipient's healing pro- cess must take over. Before doing so, however, the seeds must compete against or clear away retained debris and unwanted organic material within the soil. Meanwhile, he said conven- tional dehydrated membrane is like having dirt where all the beneficial nutrients have been denatured out by heat and yet there's retention of debris and competing organic material. Decellularized basement membrane de- serves its own category, according to Dr. Desai, akin to having a purified, nutrient-rich soil to plant seeds in. Though it doesn't have the temporary initial fertilizer, HC-HA/PTX3, as it only retains the basement membrane, the Different types of amniotic membrane products available continued on page 62

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