Is the Conjunctiva a Potential Target for Advanced Therapy Medicinal Products?

Abstract

The conjunctiva is a complex ocular tissue that provides mechanical, sensory, and immune protection for the ocular surface. It is affected by many diseases through different pathological mechanisms. If a disease is not treated and conjunctival function is not fully restored, the whole ocular surface and, therefore, sight is at risk. Different therapeutic approaches have been proposed, but there are still unsolved conjunctival alterations that require more sophisticated therapeutic options. Advanced therapy medicinal products (ATMPs) comprise a wide range of products that includes cell therapy, tissue engineering, and gene therapy. To the best of our knowledge, there is no commercialized ATMP specifically for conjunctival treatment yet. However, the conjunctiva can be a potential target for ATMPs for different reasons. In this review, we provide an overview of the advances in experimental phases of potential ATMPs that primarily target the conjunctiva. Important advances have been achieved through the techniques of cell therapy and tissue engineering, whereas the use of gene therapy in the conjunctiva is still marginal. Undoubtedly, future research in this field will lead to achieving commercially available ATMPs for the conjunctiva, which may provide better treatments for patients.

In situ gels: The next new frontier in ophthalmic drug delivery system

“…Although the conjunctiva can deliver hydrophilic molecules and macromolecules, it can also serve as an absorption pathway for biomolecules such as proteins and peptides. Most of the drug is removed by the conjunctiva and subsequently enters the systemic circulation 109,110 . This is one of the main reasons why topically injected drugs do not reach the back of the eye at effective concentrations.…”

“…Most of the drug is removed by the conjunctiva and subsequently enters the systemic circulation. 109,110 This is one of the main reasons why topically injected drugs do not reach the back of the eye at effective concentrations.…”

Autoimmunity against laminin 332

“…Preliminary evidence for the pathogenic relevance of anti-laminin 332 IgG stems from the intraindividual correlation of anti-laminin 332 IgG serum levels with disease activity ( 38 ). Apart from in-vitro organ culture models of MMP employing normal human conjunctiva ( 25 , 92 – 94 ), two mouse models of anti-laminin 332 MMP have been developed. One model reflects the inflammatory-poor variant of MMP and lesions develop independently of complement activation and the infiltration of inflammatory cells in the tissues, while the other model shows, oral, conjunctival, and skin lesions with inflammatory infiltrates and requires the involvement of the Fcγ-receptor and activation of C5aR1 ( 95 – 97 ).…”

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“…However, in cases of extensive damage caused by factors like burns, thermal trauma, or acute chemical injuries, the reconstructive treatment of the conjunctiva becomes imperative. Replacement tissues are utilized to achieve optimal outcomes in the healing process [1,2]. Several techniques have been developed to enhance the healing of conjunctival defects, including amniotic membrane transplantation, mucosal membrane transplantation, and conjunctival autograft.…”