DONOR OVERLAY FOR TREATMENT OR ALLEVIATION OF ANTERIOR CORNEAL DISORDERS

Abstract

The invention relates to methods for the treatment or alleviation of an anterior corneal disorder in a subject in need thereof comprising removing corneal epithelial cells from an eye of said subject without removing any corneal tissue or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning an overlay comprising a Bowman layer (BL), Descemet membrane (DM) and/or crystalline lens capsule on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer. The invention further relates to freeze-dried and/or gamma irradiated Bowman layer, Descemet membrane and/or crystalline lens capsule and compositions comprising the same that are useful in such methods.

Claims

1. A method for the treatment or alleviation of an anterior corneal disorder in a subject in need thereof, the method comprising: removing corneal epithelial cells from an eye of said subject without removing any corneal tissue or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning an overlay composed of a Bowman layer (BL) or composed of more than one layer, wherein each layer is composed of a BL, on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

2. An overlay composed of a Bowman layer (BL) or composed of more than one layer, wherein each layer is composed of a BL, for use in a method for the treatment or alleviation of an anterior corneal disorder in a subject, wherein said method comprises: removing corneal epithelial cells from an eye of said subject without removing any corneal or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning said overlay on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

3. A method for inducing a tissue remodeling response in the corneal stroma of a subject, wherein said corneal stroma comprises scar tissue associated with or resulting from an anterior corneal disorder, the method comprising: removing corneal epithelial cells from an eye of said subject without removing any corneal tissue or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning an overlay composed of a Bowman layer (BL) or composed of more than one layer, wherein each layer is composed of a BL, on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

4. An overlay composed of a Bowman layer (BL) or composed of more than one layer, wherein each layer is composed of a BL, for use in a method for inducing a tissue remodeling response in the corneal stroma of a subject, wherein said corneal stroma comprises scar tissue associated with or resulting from an anterior corneal disorder, and wherein said method comprises: removing corneal epithelial cells from an eye of said subject without removing any corneal or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning said overlay on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

5. A method or overlay for use according to any one of the preceding claims, wherein said corneal tissue located posterior to the corneal epithelial cell layer comprises at least part of a BL and anterior corneal stromal tissue or, where the cornea of the subject lacks a BL, said corneal tissue located posterior to the corneal epithelial cell layer comprises anterior corneal stroma.

6. A method or overlay for use according to any one of the preceding claims, wherein said overlay is positioned sutureless on said corneal tissue.

7. A method or overlay for use according to any one of the preceding claims, wherein said overlay has an average thickness of 7-600 μm, preferably 8-550 μm, more preferably 10-500 μm and/or has an average diameter of 1-12 mm.

8. A method or overlay for use according to any one of the preceding claims, wherein at least 80% of corneal epithelial cells covering the part of the anterior surface of the corneal tissue that will be covered by the overlay is removed from the eye of said subject.

9. A method or overlay for use according to any one of the preceding claims, wherein said overlay consists of one or more donor BLs.

10. A method or overlay for use according to any one of the preceding claims, wherein said one or more donor BLs is or are selected from the group consisting of human or animal BL or BLs.

11. A method or overlay for use according to any one of claims 1, 2 and 5-10 wherein said treatment or alleviation comprises inducing a wound healing response at the interface between said overlay and the Bowman layer of the subject and/or a tissue remodeling response in the corneal stroma of the subject.

12. A method or overlay for use according to any one of the preceding claims wherein said overlay or said BL is treated with a substance selected from the group consisting of dyes, riboflavin, adjuvants that facilitate visualization and active components.

13. A method or overlay for use according to claim 12, wherein said active component is selected from the group consisting of stromal growth factors, epithelial growth factors and any combination thereof.

14. A method or overlay for use according to any one of the preceding claims, wherein the cornea of said subject comprises at least part of a BL, preferably wherein said part comprises at least 10% of an intact Bowman's layer.

15. A method or overlay for use according to any one of the preceding claims, wherein said method further comprises allowing the overlay to dry in and/or positioning a soft bandage lens onto the eye.

16. A method or overlay for use according to any one of the preceding claims, wherein said overlay is stained, preferably with a vital dye, before said overlay is positioned on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

17. A method or overlay for use according to any one of the preceding claims, wherein said anterior corneal disorder is selected from the group consisting of a corneal curvature disorder, a corneal instability disorder, a corneal wound healing disorder, a corneal surface disorder, a corneal defect, melt or peripheral thinning, an ocular surface disease and a refractive error of the eye.

18. A composition composed of more than one layer, wherein each layer independently comprises a Bowman layer (BL).

19. A composition according to claim 18, said composition or one or more of said layers are treated with a substance selected from the group consisting of dyes, riboflavin, adjuvants that facilitate visualization and active components.

20. A composition according to claim 19, wherein said active component is selected from the group consisting of stromal growth factors, epithelial growth factors and any combination thereof.

21. A composition according to any one of claims 18-20, wherein said composition has an average thickness of 7-600 μm and/or has an average diameter of 1-12 mm.

22. A composition according to any one of claims 18-21, wherein the composition is freeze-dried and/or gamma-irradiated.

23. A composition according to any one of claims 18-22 for use in therapy.

24. A composition according to any one of claims 18-22 for use in a method for the treatment or alleviation of an anterior corneal disorder in a subject, wherein said method comprises: removing corneal epithelial cells from an eye of said subject without removing any corneal or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning said composition on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

25. A method for the treatment or alleviation of an anterior corneal disorder in a subject in need thereof, the method comprising: removing corneal epithelial cells from an eye of said subject without removing any corneal tissue or other ocular tissue located posterior to the corneal epithelial cell layer; and positioning a composition according to any one of claims 18-22 on the anterior surface of said corneal tissue located posterior to the corneal epithelial cell layer.

26. A method or composition for use according to claim 24 or 25 wherein said treatment or alleviation comprises inducing a wound healing response at the interface between said overlay and the Bowman layer of the subject and/or a tissue remodeling response in the corneal stroma of the subject.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0115] FIG. 1: comparison of prior published procedures and the procedure of the present invention.

[0116] A. Epikeratophakia as described in U.S. Pat. No. 4,662,881 has been performed for at least 5 decades. The graft usually consists of donor stroma with its Bowman layer on top. Since a wound healing response is virtually absent at the donor-to-host interface (ie. at the donor stroma-to-recipient Bowman layer interface), the graft is ‘tucked in’ into the host stroma in the periphery, to allow for stroma-to-stroma wound healing in these areas, and therefore long term fixation of the graft.

[0117] B. From a wound healing perspective, a ‘tissue contact lens’ as described in US 2003/105521 A1 may be considered a type of epikeratophakia, since a wound healing response is unlikely to occur at the donor-to-host interface (i.e. at the donor stroma-to-recipient Bowman layer interface). Since the graft is not ‘tucked in’ in the corneal periphery, graft may remain at risk of dislocation due to a lack of wound healing induced tissue fixation.

[0118] C. An absent wound healing response at the donor-to-host interface (ie. at the recipient stroma-to-donor Bowman layer interface) may be exploited to avoid scar tissue (re)formation in the management of stromal haze after photorefractive keratectomy (PRK) by positioning a donor Bowman layer onto an post-laser ablated stromal bed, as described in Lie et al 2010. Although effective in improving the visual acuity through minimizing scar tissue formation at the interface, the graft may remain at risk of dislocation because of the lack of wound healing induced tissue fixation.

[0119] D. Procedure according to the present invention. In contrast to the absence of a wound healing response at the donor-to-host interface (ie. at a stroma-to-Bowman layer interface), wound healing does occur if a donor Bowman layer is positioned onto the recipient anatomical Bowman layer, thereby providing long term tissue fixation.

[0120] FIG. 2: Scheimpflug images of a cornea before (A) and six months after (B) a BL overlay (arrows) in a patient with advanced keratoconus (asterix). The arrowheads point to the contact lens that is in-situ over the BL overlay. (C) Pentacam topography maps, pre- (middle), postoperative (left) and difference map (right), of the same cornea at, show up to 15-16 diopters in corneal flattening.

[0121] FIG. 3: Slit-lamp images (A & B), Scheimpflug image (C) and AC-OCT image (D) two weeks after a BL overlay (arrows) in an eye with diurnal variation in visual acuity resulting from refractive fluctuation owing to corneal instability after radial keratotomy surgery. (E) Pentacam topography maps pre-operatively and up to one year postoperatively, of a cornea after a BL overlay in the same patient. Note the more regular topography over time.

[0122] FIG. 4: An eye that underwent isolated Bowman layer overlaying in accordance with the present invention, before and at 3 and 6 months after surgery. Note the flattening effect from Kmax 67D (G) to 58D (H) to 56D (I), attributed to wound healing induced tissue contraction and fixation. The central cornea also shows remodeling displayed by less reflective tissue (A-C) and improving central corneal clarity (D-F). In addition, the eye shows a white opacities preoperative of stromal scare tissue (see white arrow in D), that disappears after surgery.

[0123] FIG. 5: Slit-lamp images of two cases, before and at 1 month and at 12 months after BL onlay grafting for herpetic scarring. Note the superficial anterior central opacities of the cornea preoperatively (white arrows). Postoperatively, the cornea became relatively smoother and more transparent, and the BL was completely integrated and epithelialized, being only visible at its far edges (light grey arrows in 1 m and 12 m images).

EXAMPLES

[0124] Case 1:

[0125] In the treatment of corneal curvature disorders (Group I), it was found that the donor tissue overlay was effective in 1) reducing the steepened corneal curvature up to 20 diopters and 2) stabilizing the keratoconus, that is, to halt progression (FIG. 2).

[0126] An eye with advanced keratoconus (>70 diopters) had a 9.0 mm single-layer BL overlay positioned onto the host remnant BL under topical anesthesia. Six months later, the cornea showed up to 15-16 diopters of flattening of the anterior corneal surface and thereafter, topography images appeared stable over time (FIG. 2).

[0127] If desired, a multi-layered donor tissue overlay can be used and/or the procedure can be repeated, to obtain a stronger initial effect or a cumulative effect, since advanced keratoconic corneas may show steepening up to more than 80 diopters (while a non-keratoconic cornea curvature averages to about 43 diopters).

[0128] Case 2:

[0129] In the management of corneal instability disorders (Group II), a similar approach was found to be effective in stabilizing the cornea and therefore to reduce the diurnal fluctuation in refractive error (FIG. 3). Commonly a single layer donor tissue overlay was sufficient to obtain the desired clinical effect.

[0130] An eye with diurnal fluctuation in visual acuity >25 years after radial keratotomy surgery had a 8.0 mm single BL overlay positioned onto the (previously incised) host BL under topical anesthesia. At one month, the diurnal fluctuation in visual acuity had subjectively diminished to acceptable levels and topography imaging showed a mild steepening of the cornea up to one year (FIG. 3).

[0131] Further Patient Examples (Cases 3-9) and Potential Clinical Applications:

[0132] In corneal wound healing disorders, defects, melts, peripheral thinning, surface irregularities, and ocular surface disease (Groups III, IV and V), a donor tissue overlay was found to be clinically effective in most cases. Both these groups cover a wide range of pathology. In general, a donor tissue overlay showed excellent results in cases without active inflammation, such as haze or scarring after excimer laser surgery and a postinfectious scar in the quiet phase. In contrast to other methods currently available, the donor tissue overlay was found not to dissolve over time.

[0133] The donor tissue overlay can also be used to manage refractive errors of the eye by using a single or most commonly a multi-layered overlay that is allowed to stay in-situ for several weeks to let the epithelium grow over. The overlay may then be tuned up by using excimer laser photoablation, so that the corneal curvature is re-shaped similarly to a virgin cornea undergoing excimer laser surgery, with a treatment range from approximately +6 to −12 diopters, or more preferably from +4 to −6 diopters. The major advantage of remodeling a donor tissue overlay instead of the patient's own cornea, is that the procedure allow for a curvature change without compromising the patient's cornea itself, so that the procedure can be ‘undone’ if desired (for example if the final result is disappointing), to return the pre-operative situation.

Case 3: An eye with moderate keratoconus (about 55 diopters) had a 9.0 mm multi-layer BL overlay positioned onto the host remnant BL under topical anesthesia. Six months later, the cornea showed up to 11 diopters of flattening of the anterior corneal surface and thereafter, topography images appeared stable over time.
Case 4: An eye with post-excimer laser (LASIK) ectasia (about 50 diopters) had a 9.0 mm single BL overlay positioned onto the host BL under topical anesthesia. Three months later, the cornea showed up to 5 diopters of flattening of the anterior corneal surface and thereafter, topography images appeared stable over time.
Case 5: An eye with wound dehiscence >15 years after penetrating keratoplasty had a 9.0 mm single BL overlay positioned onto the central graft under local anesthesia. At six months, topography imaging showed a more regular anterior corneal surface (K-value re-distribution).
Case 6: An eye with a post-infectious ocular herpes simplex scar in the quiet phase had a single BL overlay positioned onto the central cornea under local anesthesia. Postoperatively, slit-lamp imaging showed a slow diminution of the opacity, up to 2 years.
Case 7: In an eye with a subepithelial scar (haze grade 4) after PRK, a superficial keratectomy was performed after positioning a single BL overlay across the cornea under local anesthesia. Postoperatively, no recurrence of the scar was observed up to 8 years.
Case 8: In an eye with a −2 diopter refractive error, a multilayered BL overlay was positioned onto cornea under local anesthesia. After six months, a PRK was done using routine nomograms to correct the refractive error, that is to flatten the anterior corneal curvature (reduce the corneal power).
Case 9: An eye that underwent isolated Bowman layer overlaying in accordance with the present invention to treat keratoconus, before and at 3 and 6 months after surgery (FIG. 4). Note the flattening effect from Kmax 67D (FIG. 4G) to 58D (FIG. 4H) to 56D (FIG. 4I), attributed to wound healing induced tissue contraction and fixation. The central cornea also shows remodeling displayed by less reflective tissue (FIG. 4A-C) and improving central corneal clarity (FIG. 4D-F). In addition wound healing in the underlying stromal tissue resulted in mitigation and/or disappearance of stromal scar tissue (response), preoperatively visible as a white opacity in FIG. 4D.

Cases 10 and 11:

[0134] Two cases of herpetic scarring that underwent isolated Bowman layer overlaying in accordance with the present invention. Eyes of both cases showed a denser scar (see white arrows in FIG. 5 preoperatively). The depth of the scar was 150 and 130 mm approximately, respectively for case 1 and case 2, as measured with anterior segment optical coherence tomography.
BL onlay grafting was performed in both cases. From a donor globe obtained less than 36 hours postmortem, a corneoscleral button was excised, the endothelium (if viable) was AQ:3 peeled off to be used for DMEK surgery, and the remaining anterior button was mounted on a custom-made holder. The donor BL was stripped from the anterior stroma with modified McPherson forceps so that a BL sheet was obtained.9 The BL formed a roll spontaneously and was stored in an organ culture medium until the time of transplantation.
The surgery was performed under retrobulbar anesthesia. The recipient epithelium was removed from the corneal surface by using surgical sponges and a hockey stick knife. The stromal bed was then irrigated to remove calcium and epithelial remnants. The most superficial corneal rests of subepithelial fibrosis were then gently debrided using a hockey stick knife. Once the corneal surface was as smooth as possible, a BL graft (9.0 mm in case 1 and 8.5 mm in case 2) stained with 0.06% trypan blue solution (VisionBlue; DORC International, Zuidland, Netherlands) was carefully positioned (epithelial side up) without folds onto the recipient cornea and allowed to dry. Amniotic membrane was then sutured covering the cornea to improve postoperative reepithelialization, and a soft bandage lens was placed on the eye.
After surgery, a well-integrated BL graft was observed in both cases, completely epithelialized and without signs of decentration or dislocation. Complete and rapid reepithelialization was seen along with a steady improvement of the corneal clarity and relative “smoothening” of the anterior corneal surface. Postoperatively, a steady improvement in the corneal clarity was observed, when compared with the preoperative state. Throughout the follow-up period (12 months), the corneal opacity did not recur. The presence of the BL graft could be confirmed on slitlamp biomicroscopy and anterior segment optical coherence tomography, by the outer edges and a faint line underneath the epithelium (FIG. 5).

REFERENCES

[0135] Birbal R S, Ni Dhubhghaill S, Bourgonje V J A, Hanko J, Ham L, Jager M J, Boehringer S, Oellerich S, Melles G R J. Five-year graft survival and clinical outcomes of 500 consecutive cases after Descemet membrane endothelial keratoplasty. Cornea. 2019. Accepted (status September 2019). [0136] Groeneveld-van Beek E A, Parker J, Lie J T, Bourgonje V, Ham L, van Dijk K, van der Wees J, Melles G R. Donor Tissue Preparation for Bowman Layer Transplantation. Cornea. 2016 December; 35(12):1499-1502. [0137] Lie J, Droutsas K, Ham L, Dapena I, Ververs B, Otten H, van der Wees J, Melles G R. Isolated Bowman layer transplantation to manage persistent subepithelial haze after excimer laser surface ablation. J Cataract Refract Surg. 2010 June; 36(6):1036-41. [0138] Melles G R, Wijdh R H, Nieuwendaal C P. A technique to excise the descemet membrane from a recipient cornea (descemetorhexis). Cornea. 2004; 23:286-8. [0139] Melles G R J, Ong S, Ververs B, Van der Wees J. Descemet membrane endothelial keratoplasty (DMEK). Cornea 2006; 25:987-90. [0140] Parker J S, van Dijk K, Melles G R. Treatment options for advanced keratoconus: A review. Sury Ophthalmol. 2015 September-October; 60(5):459-80. [0141] Parker J S, Huls F, Cooper E, Graves P, Groeneveld-van Beek E A, Lie J, Melles G R J. Technical feasibility of isolated Bowman layer graft preparation by femtosecond laser: a pilot study. Eur J Ophthalmol. 2017 Nov. 8; 27(6):675-677. [0142] Sharma B, Dubey A, Prakash G, Vajpayee R B. Bowman's layer transplantation: evidence to date. Clin Ophthalmol. 2018 Mar. 5; 12:433-437. [0143] Spinozzi D, Miron A, Bruinsma M, Dapena I, Lavy I, Binder P, Rafat M, Oellerich S, Melles G R J. Evaluation of the suitability of biocompatible carriers as artificial transplants using cultured porcine corneal endothelial cells. Curr Eye Res 2019; 44:243-9. [0144] van Dijk K, Parker J, Tong C M, Ham L, Lie J T, Groeneveld-van Beek E A, Melles G R. Midstromal isolated Bowman layer graft for reduction of advanced keratoconus: a technique to postpone penetrating or deep anterior lamellar keratoplasty. JAMA Ophthalmol. 2014 Apr. 1; 132(4):495-501. [0145] van Dijk K, Liarakos V S, Parker J, Ham L, Lie J T, Groeneveld-van Beek E A, Melles G R. Bowman layer transplantation to reduce and stabilize progressive, advanced keratoconus. Ophthalmology. 2015 May; 122(5):909-17.