Ignite Creation Date:
2024-05-06 @ 8:08 PM
Last Modification Date:
2024-10-26 @ 3:21 PM
Study NCT ID:
NCT06265298
Status:
RECRUITING
Last Update Posted:
2024-02-20
First Post:
2024-01-24
Brief Title:
Implementation of a Protocol for the Transdifferentiation of Buccal Mucosal Epithelium Into Corneal Epithelium
Sponsor:
University Hospital Montpellier
Organization:
University Hospital Montpellier
Study Overview
Official Title:
Implementation of a Protocol for the Transdifferentiation of Buccal Mucosal Epithelium Into Corneal Epithelium
Status:
RECRUITING
Status Verified Date:
2024-08
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
TransBuCor
Brief Summary:
Objectives The transparent surface of the eye called the cornea plays a crucial role in transmitting light to the retina and in protecting the eye On its external surface the cornea is composed of a constantly renewing multistratified epithelium This mechanism is fueled by stem cells located in the limbus the transition zone between the cornea and the sclera Limbal Stem Cell Deficiency LSCD is characterized by a decrease or cessation of epithelial renewal and neovascularization of the cornea Consequently the cornea loses its integrity and transparency This visually impairing condition is currently in a therapeutic impasse as only autologous limbal or allogeneic corneal grafts are viable options but they pose significant risks to patients
Studies have shown that the oral cavity contains stem cells that can be isolated cultured and transdifferentiated into limbal stem cells LSCs However to date these studies are limited and no protocol has been validated In this study the advantage of the accessibility of the oral cavity is used to develop a protocol for differentiating cells from the oral mucosa into limbal stem cells LSCs for use in a future clinical trial with patients
Methodology This prospective monocentric study will be conducted on patients from the ophthalmology department of the Montpellier University Hospital who have an indication for conjunctival reconstruction After obtaining consent from the patients cells from the oral wall will be sent to the tissue bank of the Montpellier University Hospital where they will be cultured Finally the transdifferentiation steps will be analyzed by the Eye research team at the Institute of Neuroscience in Montpellier which is collaborating on the project The investigators have established objective factors to assess the success of the developed protocol based on the literature i 3 of stem cells in primary cultures ii 10 aborted colonies iii Expression of LSC markers Pax6 Krt14 p63
Studies have shown that the oral cavity contains stem cells that can be isolated cultured and transdifferentiated into limbal stem cells LSCs However to date these studies are limited and no protocol has been validated In this study the advantage of the accessibility of the oral cavity is used to develop a protocol for differentiating cells from the oral mucosa into limbal stem cells LSCs for use in a future clinical trial with patients
Methodology This prospective monocentric study will be conducted on patients from the ophthalmology department of the Montpellier University Hospital who have an indication for conjunctival reconstruction After obtaining consent from the patients cells from the oral wall will be sent to the tissue bank of the Montpellier University Hospital where they will be cultured Finally the transdifferentiation steps will be analyzed by the Eye research team at the Institute of Neuroscience in Montpellier which is collaborating on the project The investigators have established objective factors to assess the success of the developed protocol based on the literature i 3 of stem cells in primary cultures ii 10 aborted colonies iii Expression of LSC markers Pax6 Krt14 p63
Detailed Description:
1 Recall on Corneal Anatomy and Histology
The cornea is an essential ocular component for vision often referred to as the first transparent porthole at the front of the eye It is the first structure that light encounters upon entering the eye Its primary role is to converge incident light rays which then proceed towards the lens before reaching the retina and initiating the visual cascade
The cornea is an avascular and transparent tissue composed of five layers corneal epithelium Bowmans layer corneal stroma Descemets membrane and corneal endothelium
The corneal epithelium is the outermost layer of the cornea consisting of corneal epithelial cells accounting for about 10 of the entire cornea This layer constantly regenerates with complete renewal occurring every seven days Scratches on this layer generally heal well
The Bowmans layer helps bind the corneal epithelium and stroma together This layer cannot regenerate once damaged potentially leading to permanent scars that can affect vision
The corneal stroma represents about 90 of the cornea and is composed of collagen and keratocytes
Descemets membrane is made up of collagen and separates the corneal stroma from the endothelium This layer gradually thickens with age
The corneal endothelium is the innermost layer and aids in transporting fluid from other corneal layers Damage to this layer can compromise this process and negatively impact a persons vision
2 Renewal and Healing Process of Corneal Epithelium
Corneal epithelial cells regenerate within 3 to 10 days through constant renewal from limbal stem cells located at the limbus transition zone between the cornea and sclera in the basal cell layer within pigmented crypts called Vogts palisades
Deficiency In Limbal Stem Cells LSCD is characterized by a loss or impairment of limbal stem cells crucial for corneal epithelial repopulation and limbal barrier function
The etiologies of LSCD can be genetic PAX6 secondary to chronic inflammation eg severe allergic keratoconjunctivitis or ocular rosacea acquired through infection such as herpetic keratitis or secondary to a blistering disease such as Steven-Johnson syndrome or Lyell syndrome LSCD can also be acquired through trauma from chemical or thermal burns Etiologies can also be idiopathic
When these stem cells are lost the corneal epithelium is unable to repair and renew itself This leads to epithelial degradation persistent epithelial defects conjunctivalization corneal neovascularization corneal scars and chronic inflammation These factors contribute to photophobia loss of corneal clarity vision loss and chronic pain This makes corneal transplantation impossible as it would be rejected andor exhibit poor healing
Current solutions for addressing this cause of corneal blindness are limited Techniques include autologous limbal grafts from the patients contralateral eye but this may pose risk and is not possible when the pathology is bilateral Allogeneic grafts are highly risky for rejection and require systemic immunosuppressive treatment
3 Mucous Membrane Grafts in Periorbital Reconstruction
Oral mucosa grafting is a well-established surgical technique for treating conjunctival deficiencies and scars Oral mucosa possesses biological properties similar to conjunctiva both being composed of one or more layers of epithelial cells covering a loose connective tissue layer It can be harvested repeatedly with the donor site easily accessible and widely available Donor site morbidity is low and surgery is generally well-tolerated by patients Moreover the surgical technique is relatively simple making oral mucosa an ideal candidate for replacing conjunctival anomalies
Oral mucosa grafts have been used not only for treating contracted sockets in anophthalmic patients and reconstructing the ocular surface and fornix in patients after tumor resection but also for treating refractive pterygium and in patients with pemphigoid or ocular symblepharon It is also the most commonly used tissue in treating post-surgical complications including conjunctival deficiencies after glaucoma retinal surgery corneal melts related to keratoprosthesis and covering the dacryocystorhinostomy tract Additionally oral mucosa has been used to repair intractable sclerocorneal melts caused by severe chemical burns
Some teams have proposed using buccal mucosa cells and transdifferentiating them into limbal stem cells The oral cavity is easily accessible and stem cells can be isolated from the mucosa in a minimally invasive and low-risk manner for the patient These cells have a high differentiation potential and express markers of embryonic stem cells Tra2-49 Tra2-54 SSEA4 Oct4 Sox2 and Nanog as well as the neural crest marker Nestin However human trials are still in the preliminary stage and no therapy has been validated to date
In this proof-of-concept study the aim is to develop a protocol for differentiating oral mucosa cells into limbal stem cells for use in a future clinical trial with patients
The cornea is an essential ocular component for vision often referred to as the first transparent porthole at the front of the eye It is the first structure that light encounters upon entering the eye Its primary role is to converge incident light rays which then proceed towards the lens before reaching the retina and initiating the visual cascade
The cornea is an avascular and transparent tissue composed of five layers corneal epithelium Bowmans layer corneal stroma Descemets membrane and corneal endothelium
The corneal epithelium is the outermost layer of the cornea consisting of corneal epithelial cells accounting for about 10 of the entire cornea This layer constantly regenerates with complete renewal occurring every seven days Scratches on this layer generally heal well
The Bowmans layer helps bind the corneal epithelium and stroma together This layer cannot regenerate once damaged potentially leading to permanent scars that can affect vision
The corneal stroma represents about 90 of the cornea and is composed of collagen and keratocytes
Descemets membrane is made up of collagen and separates the corneal stroma from the endothelium This layer gradually thickens with age
The corneal endothelium is the innermost layer and aids in transporting fluid from other corneal layers Damage to this layer can compromise this process and negatively impact a persons vision
2 Renewal and Healing Process of Corneal Epithelium
Corneal epithelial cells regenerate within 3 to 10 days through constant renewal from limbal stem cells located at the limbus transition zone between the cornea and sclera in the basal cell layer within pigmented crypts called Vogts palisades
Deficiency In Limbal Stem Cells LSCD is characterized by a loss or impairment of limbal stem cells crucial for corneal epithelial repopulation and limbal barrier function
The etiologies of LSCD can be genetic PAX6 secondary to chronic inflammation eg severe allergic keratoconjunctivitis or ocular rosacea acquired through infection such as herpetic keratitis or secondary to a blistering disease such as Steven-Johnson syndrome or Lyell syndrome LSCD can also be acquired through trauma from chemical or thermal burns Etiologies can also be idiopathic
When these stem cells are lost the corneal epithelium is unable to repair and renew itself This leads to epithelial degradation persistent epithelial defects conjunctivalization corneal neovascularization corneal scars and chronic inflammation These factors contribute to photophobia loss of corneal clarity vision loss and chronic pain This makes corneal transplantation impossible as it would be rejected andor exhibit poor healing
Current solutions for addressing this cause of corneal blindness are limited Techniques include autologous limbal grafts from the patients contralateral eye but this may pose risk and is not possible when the pathology is bilateral Allogeneic grafts are highly risky for rejection and require systemic immunosuppressive treatment
3 Mucous Membrane Grafts in Periorbital Reconstruction
Oral mucosa grafting is a well-established surgical technique for treating conjunctival deficiencies and scars Oral mucosa possesses biological properties similar to conjunctiva both being composed of one or more layers of epithelial cells covering a loose connective tissue layer It can be harvested repeatedly with the donor site easily accessible and widely available Donor site morbidity is low and surgery is generally well-tolerated by patients Moreover the surgical technique is relatively simple making oral mucosa an ideal candidate for replacing conjunctival anomalies
Oral mucosa grafts have been used not only for treating contracted sockets in anophthalmic patients and reconstructing the ocular surface and fornix in patients after tumor resection but also for treating refractive pterygium and in patients with pemphigoid or ocular symblepharon It is also the most commonly used tissue in treating post-surgical complications including conjunctival deficiencies after glaucoma retinal surgery corneal melts related to keratoprosthesis and covering the dacryocystorhinostomy tract Additionally oral mucosa has been used to repair intractable sclerocorneal melts caused by severe chemical burns
Some teams have proposed using buccal mucosa cells and transdifferentiating them into limbal stem cells The oral cavity is easily accessible and stem cells can be isolated from the mucosa in a minimally invasive and low-risk manner for the patient These cells have a high differentiation potential and express markers of embryonic stem cells Tra2-49 Tra2-54 SSEA4 Oct4 Sox2 and Nanog as well as the neural crest marker Nestin However human trials are still in the preliminary stage and no therapy has been validated to date
In this proof-of-concept study the aim is to develop a protocol for differentiating oral mucosa cells into limbal stem cells for use in a future clinical trial with patients
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None