Determining the beneficial properties of bovine amniotic membrane and its efficacy as a therapy for corneal healing
Corneal ulceration, or ulcerative keratitis, is one of the most common ocular diseases observed in dogs and horses, particularly after trauma. Superficial corneal ulcers can heal without complications in a noninfected environment, but severe ulcerative keratitis can progress rapidly and lead to impaired vision and loss of the eye. Corneal healing is modulated by complex signaling pathways which involve proteinases, proteinase inhibitors, growth factors, and pro- and anti-inflammatory cytokines. For adequate corneal healing, it is necessary to have a well-balanced interaction between proteinases and their inhibitors, as well as anti-angiogenic and angiogenic factors. Therefore, keeping this balance should be the target approach in treating ulcerative keratitis. Some medications can alter the ocular microenvironment and help keep this balance, improving corneal healing. In this dissertation work, bovine amniotic membrane homogenate (BAMH) has been investigated to evaluate its efficacy as therapy during corneal healing. The first step was to confirm if BAMH contains tissue inhibitor of metalloproteinases (TIMPs), the most effective metalloproteinase inhibitors in the cornea, and if BAMH is able to inhibit metalloproteinases (MMPs) -2 and -9, which are detrimental when in excess. After confirming these properties in vitro, BAMH effectiveness during healing process was evaluated in an ex vivo wounded cornea model, topically applying the BAMH and comparing its effect with EDTA and a control. The BAMH was able to reduce corneal healing time significantly when compared to the controls, suggesting that it is a promising treatment for stromal and epithelial ulcers. Subsequently, the next step was to develop a protein profile of the bovine amniotic membrane (BAM) to understand how BAMH could potentially influence corneal ulcer therapy. To do so, BAM proteins were identified using high-throughput proteomic analysis. The results revealed that many of the expressed proteins in the BAM were also present in the cornea and involved in several biological and molecular functions. In conclusion, BAMH appears to be a promising treatment for corneal ulcers, presenting TIMP -1, TIMP -2 and TIMP -3, inhibiting MMP-2 and MMP-9 in vitro, accelerating the corneal healing time, and presenting numerous beneficial proteins important for corneal health and function.
Bovine amniotic membrane, homogenate, metalloproteinases (MMPs), TIMPs, corneal healing, proteomic composition, ex vivo corneas, in vitro MMPs -2 and -9 reductive activities
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign