2 Clinical Trials for Various Conditions
Limbal Stem Cell Deficiency (LSCD) is a blinding disease that accounts for an estimated 15-20% of corneal blindness worldwide. Current treatments are limited. Traditional corneal transplantation with penetrating keratoplasty (PKP) is ineffective in treating these patients. Without a healthy population of limbal stem cells (LSC) to regenerate the corneal epithelium, standard corneal transplants will not re-epithelialize and will rapidly scar over or melt. The limbal niche is the microenvironment surrounding the LSCs that is critical for maintaining their survival and proliferative potential under physiologic conditions. Extracellular signals from the microenvironment are critical to the normal function and maintenance of pluripotent stem cells. Identifying an effective niche replacement is thus an important focus of limbal stem cell research and critical for advancing treatments for LSCD. Descemet's membrane (DM), an acellular, naturally occurring, basement membrane found on the posterior surface of the cornea, is a promising niche replacement. DM is routinely isolated and transplanted intraocularly with associated donor corneal endothelium for treatment of diseases like Fuchs' dystrophy and corneal bullous keratopathy that specifically affect DM and corneal endothelium. However, its application on the ocular surface has not been explored. DM is optically clear and highly resistant to collagenase digestion. This makes it very attractive as a long-term corneal on-lay and niche replacement on the surface of the eye. The anterior fetal banded layer of DM shares key compositional similarities with limbal basement membrane, which is a major component of the limbal niche. These similarities include limbus-specific extracellular matrix proteins such as collagen IV that is restricted to the α1, α2 subtypes, vitronectin, and BM40/SPARC. Of these, vitronectin and BM40/SPARC are known to promote proliferation of LSCs and induced pluripotent stem cells (iPSC) in culture. Because of this, DM is a promising biological membrane for establishing a niche-like substrate on the corneal surface in patients with LSCD. The purpose of this pilot study is to investigate the clinical efficacy of using DM as a corneal on-lay to promote corneal re-epithelialization in partial LSCD.
This study will investigate congenital or developmental eye abnormalities that affect the iris, cornea and lens, and are usually accompanied by elevated pressure within the eye. These disorders can cause vision loss, and the increased eye pressure can lead to glaucoma, a condition that may also cause loss of eyesight. Patients with eye anterior chamber eye disease, such as Axenfeld's syndrome, Rieger's anomaly, Peter's anomaly, iridocorneal endothelial syndrome, megalocornea, ocular hypertension, and others, are eligible for this study. Participants will have a medical examination, family history, and comprehensive eye examination. Tests and procedures may include photographs of the cornea, iris, and the structure through which fluid that normally circulates behind the cornea drains out of the eye. Some patients may undergo indentation tonography to measure how easily this fluid drains. In this procedure, the patient lies on an examination table and both eyes are numbed with eye drops. A small instrument (tonometer) is placed on the surface of one eye, and with the other eye, the patient looks at an overhead light. Other tests may include photographs of the back of the eye and ultrasound imaging of the structures of the eye. A blood sample may be drawn to study the genetic disorder responsible for the disease. Patients will have follow-up examinations every 6 months for the duration of the study. Medical or surgical therapy will be recommended, as appropriate, for patients who develop elevated eye pressure or vision loss.