Amniotic membrane transplantation for persistent epithelial defects with ulceration

Treatment of a large corneal perforation with a multilayer of amniotic membrane and TachoSil

OBJECTIVE

To describe a novel surgical technique for the sealing of large corneal perforations.

METHOD

Case report of a perforated, 3-mm, postherpetic, corneal ulcer. A single layer of amniotic membrane was sewn to the internal surface of the cornea. An absorbable fibrin sealant patch (TachoSil) was placed in the area of the perforation, and a folded double layer of amniotic membrane was finally sewn to the external face of the cornea.

RESULT

Surgery without complications, leading to restoration of the anterior chamber and good subjective tolerance.

CONCLUSION

The reported technique seems to represent a good alternative emergency procedure for the management of corneal perforations larger than 2 mm.

Effects of serum-free storage on morphology, phenotype, and viability of ex vivo cultured human conjunctival epithelium

The use of amniotic membrane (AM) represents one of the major developments in ocular surface reconstruction. However, in a study on patients with primary pterygium, transplantation of AM with ex vivo expanded human conjunctival epithelial cells (HCjE) promoted earlier epithelialization than AM alone. We previously showed that cultured human limbal epithelial cells maintain their morphology, phenotype, and viability for one week when stored at 23°C. The current study investigates the feasibility of storing HCjE in HEPES-MEM and Optisol-GS at 23°C for 4 and 7 days, respectively. The five experimental groups were analyzed by light microscopy, immunohistochemistry, transmission electron microscopy, and a viability assay. The ultrastructural integrity of cultured HCjE was well preserved following 4 days of storage, however, 7 days of storage resulted in some loss of cell-cell contacts and epithelial detachment from the amniotic membrane. The number of microvilli in cultured HCjE not subjected to storage was 2.03±0.38 microvilli/μm. In comparison, after 4 and 7 days of HEPES-MEM storage this number was 1.69±0.54 microvilli/μm; P=0.98 and 0.89±1.0 microvilli/μm; P=0.28, respectively. After Optisol-GS storage for 4 and 7 days, the mean number of microvilli was 1.07±1.0 microvilli/μm; P=0.47 and 0.07±0.07 microvilli/μm; P=0.03, respectively. The number of cell layers in cultured HCjE not subjected to storage was 4.4±0.3 cell layers, as opposed to 4.0±0.9 cell layers; P=0.89 after 4 days of HEPES-MEM storage and 2.8±0.6 cell layers; P=0.01 after 7 days of storage in HEPES-MEM. The number of cell layers after 4 and 7 days of storage in Optisol-GS was 3.7±0.2 cell layers; P=0.46 and 3.4±0.4 cell layers; P=0.18, respectively. The expression of markers for undifferentiated cells (ΔNp63α, ABCG2 and p63), proliferating cells (Ki67 and PCNA), goblet cells (Ck7 and MUC5AC), stratified squamous epithelial cells (Ck4), and apoptotic cells (caspase-3) in cultured HCjE appeared to be unchanged after 4 and 7 days of HEPES-MEM and Optisol-GS storage. The percentage of viable cells in cultured HCjE not subjected to storage (91.4%±3.2%) was sustained after 4 and 7 days of storage in HEPES-MEM (94.1%±4.5%; P=0.99 and 85.1%±13.7%; P=0.87, respectively) as well as after 4 and 7 days of storage in Optisol-GS (87.7%±15.2%; P=0.97 and 79.8%±15.7%; P=0.48, respectively). We conclude that cultured HCjE may be stored for at least 4 days in serum-free conditions at 23°C while maintaining the phenotype and viability. HEPES-MEM appears to be comparable to Optisol-GS for serum-free storage with preservation of the ultrastructure for at least 4 days.

Corneal surface reconstruction using adult mesenchymal stem cells in experimental limbal stem cell deficiency in rabbits

PURPOSE

To investigate the ability of mesenchymal stem cells (MSC) to transdifferentiate to corneal epithelial cells in experimental limbal stem cell deficiency in rabbits.

METHODS

Total limbal stem cell deficiency was produced in 21 right eyes of 21 New Zealand rabbits; 6 eyes served as controls (group 1, G1). After removal of the conjunctival overgrowth, five eyes received amniotic membrane transplantation (AMT; G2). In four eyes, autologous limbal stem cell transplantation from the healthy eye was performed with AMT (G3). In another six eyes, enriched autologous MSC were injected under the amniotic membrane (AM) (G4). Within 280 days, corneoscleral discs were analysed for goblet cells, cytokeratin (CK) 3/12, connexin 43, β(1) -integrin, CK 19, α-enolase, p63 and ATP-binding cassette transporter subtype G-2 (ABCG-2) distribution patterns.

RESULTS

Cultivated MSC were positive for CK 3/12 and α-enolase, but negative for ABCG-2, p63 and connexin 43. On rabbit corneas, CK 3/12 was expressed in all corneal regions in all groups, but with significantly different intensities. Among all other parameters, expression levels of ABCG-2, β(1) -integrin and connexin 43 were significantly different between the transplanted groups and the control group. After a mean follow-up time of 172 (47-280) days, goblet cells were rarely present in the central cornea (G1-4).

CONCLUSION

CK 3/12 is not highly specific for differentiated corneal epithelium. Further, goblet cells are not a reliable marker for conjunctivalization in rabbits. Expression of ABCG-2, β(1)-integrin and connexin 43 after mesenchymal stem cell transplantation may indicate their ability to maintain their stem cell character or to transdifferentiate to epithelial progenitor cells.

Surgical treatment of necrotic scleral calcification using combined conjunctival autografting and an amniotic membrane inlay filling technique

PURPOSE

To introduce a novel technique to treat necrotic scleral calcification caused by previous regional conjunctivectomy using conjunctival autografting and amniotic membrane inlay filling, and to evaluate the clinical outcome.

METHODS

Ten patients (11 eyes, 12 regions) who had undergone regional conjunctivectomy with postoperative mitomycin C (MMC) for pterygia or pingueculae were included. Scleral calcification was removed using a bevel-down crescent knife. After the conjunctival donor tissue was harvested from the upper bulbar conjunctiva, the tissue was grafted to the scleral defect and secured with sutures. Amniotic membrane was inserted randomly into spaces between the conjunctival graft and the scleral bed. Protective amniotic membrane was transplanted over the graft, with stromal side up.

RESULTS

Scleral calcification developed in ischaemic areas in 11 of the 12 regions; 50% of cases had a surface defect seen with a fluorescent dye. The grafted conjunctiva epithelialized successfully in all cases. In 10 regions, the epithelialization occurred in 1 or 2 weeks. In the remaining two regions, one region required another surgery because of graft failure, and epithelialization occurred in the last region in 9 weeks. Vascular growth into the graft from the surrounding tissue occurred in all cases in 1 to 10 weeks. The surgical wound stabilized 3 weeks postoperatively.

CONCLUSION

The combined technique had high success rates of graft survival and good revitalization of the necrotic area of scleral calcification, eliminated the need for invasive and time-consuming scleral autografting or allografting, and provided good cosmesis. Scleral ischaemia, which was caused by MMC, may induce scleral calcification.

Amniotic membrane as a scaffold for melanocyte transplantation in patients with stable vitiligo

Vitiligo is an acquired skin disease that significantly impacts the quality of life of patients. Medical treatment of vitiligo includes the use of melanocyte transplant, but the results are variable. We have treated 4 patients with either focal or generalized stable vitiligo using a graft of autologous melanocytes' culture on a denuded amniotic membrane (AM). A culture biopsy was obtained in every patient and grown in melanocytes' media for 10-14 days after which cells were transferred to a denuded AM and transplanted into the achromic lesions. Patients were followed for up to 6 months using clinical assessment of achromic lesions. Treated areas ranged between 4 cm(2) and 210.6 cm(2). Response to treatment was excellent in all patients with 90-95% repigmentation success rate. Our results demonstrate that transplantation of autologous melanocytes cultured on AM is a new, simple, and effective treatment for stable vitiligo.

The implementation of nucleic acid amplification technology testing for living tissue donors

There is a significant requirement within the United Kingdom for tissue grafts from living donors. To ensure safety, blood samples from these donors are tested for pathogens at donation, and at 180 days post donation. Nucleic acid amplification technology (NAT) permits more sensitive detection of pathogens in blood samples than serum antigen testing. NAT testing can be applied to samples from living tissue donors to eliminate the need to re-test these donors 180 days post-donation before grafts can be implanted. This has major financial and operational advantages for a tissue bank, and this manuscript describes how NAT testing was assessed and implemented by NHSBT Tissue Services. When compared to traditional serum antigen testing, NAT testing was more cost effective, more convenient for donors and resulted in a greater proportion of donated grafts being made available for transplant.

The effects of different preservation processes on the total protein and growth factor content in a new biological product developed from human amniotic membrane

The aim of this work is to quantify the total protein and growth factors content in a tissue-suspension obtained from processed human amniotic membrane (hAM). hAM was collected, frozen, freeze dried, powdered and sterilized by γ-irradiation. At each step of the process, samples were characterized for the total protein amounts by a Bradford protein assay and for the growth factor concentrations by ELISA test of the tissue suspensions. Frozen-hAM samples show higher release of total proteins and specific growth factors in the tissue suspension in comparison with freeze-dried hAM. We observed that even if the protein extraction is hindered once the tissue is dried, the powdering process allows a greater release in the tissue suspension of total proteins and growth factors after tissue re-solubilization in comparison with only the freeze-drying process (+91 ± 13% for EGF, +16 ± 4% for HGF, +11 ± 5% for FGF, +16 ± 9% for TGF-β1), and a greater release of EGF (85 ± 10%) in comparison with only the freezing process, because proteins become much readily solubilized in the solution. According with these results, we describe a protocol to obtain a new sterile biological product from hAM tissue, with well-known effects of thermal, mechanical and physical processes on the total protein and grow factors contents.

A comparison of the effectiveness between amniotic membrane homogenate and transplanted amniotic membrane in healing corneal damage in a rabbit model

PURPOSE

To determine whether amniotic membrane homogenate is as effective in healing corneal damage as amniotic membrane transplantation in a rabbit model.

METHOD

The rabbits were divided into three groups. The cornea of one eye in each rabbit was incised resulting in a defect of approximately 8 mm in diameter. Amniotic membrane transplantation was performed in the first group, and amnion homogenate was administered four times a day in the second group. The third group was the control group.

RESULTS

There were no differences in the diameter of the defects and the rate of corneal growth between the amnion transplant group and the amnion homogenate group.

CONCLUSION

Amnion homogenate is as effective as transplanted amniotic membrane in promoting corneal healing in a rabbit model.

Simultaneous amniotic membrane patch in high-risk keratoplasty

PURPOSE

To analyze the short- and intermediate-term results of simultaneous transplantation of amniotic membrane with high-risk keratoplasty.

METHODS

Between January 2002 and February 2004, a simultaneous amniotic membrane patch was transplanted with penetrating keratoplasty in 16 eyes of 16 patients. In 13 eyes, a soft contact lens was applied afterward. Corneal perforation was present in 10 of 14 eyes with emergency keratoplasty. Five patients received systemic immunosuppressive medication for 4-6 months after penetrating keratoplasty.

RESULTS

The amniotic membrane patch fell off after 8 ± 3 (range: 4-14) days without residual tissue except in 1 case. In 15 of 16 eyes, the epithelium was completely closed after 10 ± 8 (range: 4-30) days. In 3 eyes, recurrence of the epithelial defect occurred after 3-6 months. During a follow-up period of 18 ± 6 months, 13 of 16 corneal grafts were clear.

CONCLUSIONS

Simultaneous amniotic membrane transplantation and penetrating keratoplasty may improve the prognosis of corneal graft in eyes with risk of epithelial healing problems.

In vivo analysis of stromal integration of multilayer amniotic membrane transplantation in corneal ulcers

PURPOSE

To evaluate integration of amniotic membrane into the corneal stroma using laser scanning in vivo confocal microscopy and anterior segment optical coherence tomography (AS-OCT).

DESIGN

Prospective noncomparative interventional case series.

METHODS

Twenty-two eyes of 22 consecutive patients (mean age 53.9 ± 9.2 years) presenting with noninfectious corneal ulcers and stromal thinning unresponsive to medical treatment were enrolled. Multiple layers of amniotic membrane were applied over the ulcer bed to fill the ulcer crater and held in place with an overlying amniotic membrane patch, which was anchored to the surrounding cornea with 10-0 nylon interrupted sutures. Outcome measures were healing of the corneal ulcers, corneal morphology and stromal thickness changes at the ulcer site as measured by AS-OCT and surface epithelialization, stromal repopulation, and structural modifications of the amniotic membrane grafts as evaluated by confocal microscopy.

RESULTS

Follow-up extended to 12 months. Successful result was observed in 20 of 22 eyes (90.9%). AS-OCT showed that the mean residual stromal thickness at the ulcer bed was 222 ± 70 μm before surgery. The mean thickness of amniotic membrane layers at the same site was 394 ± 80 μm while the mean total corneal thickness was 623 ± 51 μm at day 1 post surgery. Thereafter a progressive reduction in thickness to 420 ± 61 μm at 6 months occurred, after which the thickness stabilized. Confocal microscopy showed that integration of the amniotic membrane tissues with corneal stroma was preceded by epithelialization over the amniotic membrane covering the ulcer. This occurred 15 ± 5 days post surgery in the successful cases. Confocal microscopy also showed that the amniotic membrane patch was degraded during the first few weeks after surgery, while the integrated amniotic tissues underwent progressive modifications characterized by early loss of amniotic epithelial cells, changes in fibrillar structure, and migration into the amniotic stroma by corneal stroma-derived cells.

CONCLUSIONS

Multiple layers of amniotic membrane can integrate into the corneal stroma with resulting increase in corneal thickness. This appears to be related to re-epithelialization of the transplanted membrane. Integrated amnion within the stromal defect undergoes progressive changes including contraction of tissue and repopulation by corneal stroma-derived cells.

Treating ocular surface disease: new agents in development

This paper reviews recent advances and investigation in the treatment of ocular surface pathology. There is significant investment in this area, paralleling the growing demand for more effective alternatives to current treatments. Clinicians are becoming more aware of surface pathology, yet the ability to treat the most common forms of ocular pathology are still limited to the few medications approved by the US Food and Drug Administration. Medicines and devices currently under investigation are very promising. It is absolutely critical to understand the emerging options and think of their role in the treatment paradigm.

Multilayered Gore-Tex patch for temporary coverage of deep noninfectious corneal defects: surgical procedure and clinical experience

PURPOSE

To evaluate the multilayer Gore-Tex patch as temporary coverage of deep, noninfectious corneal defects.

DESIGN

Retrospective, interventional case series.

METHODS

SETTING

University Medical Center Schleswig-Holstein, Kiel, Germany.

PATIENT POPULATION

Thirty-nine eyes of 38 patients with noninfectious, deep corneal defects. Underlying disorders included neurotrophic or immunologic ulcers in 37 eyes (94.9%) and traumatic defects in 2 eyes (5.1%). Intervention procedures: Corneal defects were covered with multiple Gore-Tex layers, of which the uppermost was sutured to the cornea. The Gore-Tex patch was kept in place until an appropriate corneal transplant was obtained and effective systemic immunosuppression was initiated.

MAIN OUTCOME MEASURES

Long-term preservation of the eye, frequency of resuturing of the Gore-Tex patch, and best-corrected visual acuity.

RESULTS

In 38 cases, the eye could be preserved. In 10 eyes, additional sutures were required. Before surgery, the mean best-corrected visual acuity (logMAR) was 1.14 ± 0.45 (20/250), and that at final follow-up was 1.13 ± 0.41 (20/250). The Gore-Tex patch remained in place 4 days to 32 months (mean, 6.4 ± 8.3 months) until corneal transplantation (27 eyes) or until an alternative way of defect coverage could be performed. Three eyes did not require further coverage after explantation of the Gore-Tex patch. In 6 eyes, either the Gore-Tex patch was kept in place or the patients died.

CONCLUSIONS

Temporary coverage of deep corneal defects with multilayer Gore-Tex patches allows time until an appropriate corneal transplant is obtained. The technique is particularly useful in patients with underlying autoimmune disorders, because an effective systemic immunosuppression can be initiated before corneal transplantation.

The impact of compositional topography of amniotic membrane scaffold on tissue morphogenesis of salivary gland

Amniotic membrane (AM) has been widely used in the reconstruction of oral epithelial defects. However, whether it is also effective in facilitating tissue formation of salivary gland, an appendix of oral epithelia, has never been explored. To investigate the effects and the underlying mechanism of AM on salivary gland morphogenesis, murine fetal submandibular gland (SMG) explants were cultured on different preparations of AM scaffolds. It was found that, on AM stromal scaffold, SMG demonstrated well-developed branching morphogenesis. Nonetheless, on AM epithelial scaffold, SMG epithelial cell converted to a spindle-shape, lost intercellular connection, changed cytoskeletal organization, and exhibited scattering behaviors. Meanwhile, the integrity of SMG basement membrane was dismantled as well. However, when acellular AM epithelial scaffold was used, cultured SMG demonstrated organized morphology, indicating that AM epithelial component provided specific surface features for SMG morphogenesis. To further investigate AM scaffold morphogenetic effect, it was found hepatocyte growth factor (HGF), an epithelial scattering factor, was expressed abundantly in cultivated AM epithelia. After blocking HGF function of AM, cultured SMG regained branching activity, reorganized cell adhesion and subcellular organization, and reproduced basement membranes. Therefore, AM-derived bioactive factor profoundly influences cell behaviors and structure formation of SMG. Together, this study showed that compositional topography of AM scaffold is important in affecting SMG morphogenesis. By understanding the effects of AM scaffold on SMG morphogenesis, it provides important information for rationally designing and fabricating AM scaffold for salivary gland regeneration.

Use of a hyperdried cross-linked amniotic membrane as initial therapy for corneal perforations

PURPOSE

To report the use of hyperdried cross-linked (HDCL) amniotic membrane (AM) patching with tissue adhesive as an initial therapy for corneal perforations.

METHODS

Cryopreserved AM was cross-linked with 0.1% glutaraldehyde and then dried using far-infrared rays and microwaves (hyperdry method). Three eyes of three patients with corneal perforations of up to 3 mm in diameter were included in this study. They were treated with a single-layer patch of HDCL-AM applied with a tissue adhesive (2-octyl-cyanoacrylate). We also evaluated the resistance of HDCL-AM to collagenases during in vitro digestion testing.

RESULTS

In all three cases, the corneal perforations were repaired within 28 days (range, 17-28 days). No recurrence occurred during the follow-up period (3-6 months). In the collagenase digestion testing, the HDCL-AM did not dissolve until 48 h, whereas the cryopreserved AM completely dissolved within 60 min.

CONCLUSIONS

Three cases of corneal perforations were successfully managed using HDCL-AM patching with tissue adhesive. The HDCL-AM was resistant to collagenases during in vitro digestion testing. The HDCL-AM was a useful substrate for corneal perforations. This simple surgical technique may be one of the initial therapeutic options for corneal perforations.

The impact of de-epithelialization of the amniotic membrane matrix on morphology of cultured human limbal epithelial cells subject to eye bank storage

PURPOSE

To investigate whether human limbal epithelial cells (HLEC) that have been cultured on intact or de-epithelialized amniotic membranes (AMs) demonstrate differences in morphology after 1 week of eye bank storage.

METHODS

HLEC were cultured from limbal explants for 3 weeks on intact AM and AM deprived of the amniotic epithelial cells by incubation with 0.02% ethylene diamine tetra acetic acid followed by mechanical scraping. The HLEC cultures were stored for 1 week in a closed container in a serum-based medium at 23°C. The surface morphology was assessed using scanning electron microscopy, and a quantitative comparison of desmosome and hemidesmosome numbers was performed using transmission electron microscopy.

RESULTS

Although most superficial epithelial cells were closely attached to each other, with tightly opposed cell junctions and distinct cell borders, there was evidence of some cell separation in HLEC that had been cultured on intact and denuded AM after 1 week of storage. In both experimental groups, the epithelia were well stratified, consisting of basal column-shaped cells, suprabasal cuboid wing cells, and flat squamous superficial cells, but dilated intercellular spaces were observed. The total number of desmosomes per micron was 1.39 ± 0.77 in HLEC cultured on intact AM versus 0.98 ± 0.45 in HLEC expanded on denuded AM (P = 0.76). The total number of hemidesmosomes per micron in HLEC cultured on intact AM and denuded AM was 0.87 ± 0.34 and 0.78 ± 0.31, respectively (P = 0.70).

CONCLUSIONS

Denuding of AM does not improve the structural integrity of cultured HLEC after eye bank storage.

Update on amniotic membrane transplantation

Cryopreserved amniotic membrane modulates adult wound healing by promoting epithelialization while suppressing stromal inflammation, angiogenesis and scarring. Such clinical efficacies of amniotic membrane transplantation have been reported in several hundred publications for a wide spectrum of ophthalmic indications. The success of the aforementioned therapeutic actions prompts investigators to use amniotic membrane as a surrogate niche to achieve ex vivo expansion of ocular surface epithelial progenitor cells. Further investigation into the molecular mechanism whereby amniotic membrane exerts its actions will undoubtedly reveal additional applications in the burgeoning field of regenerative medicine. This article will focus on recent advances in amniotic membrane transplantation and expand to cover its clinical uses beyond the ocular surface.

Donor age and gestational age influence on growth factor levels in human amniotic membrane

PURPOSE

Amniotic membrane (AM) is used as a biomaterial for reconstruction in ocular surface surgery. This study investigated the influence of interdonor variations and processing and preservation procedures applied to the AM on growth factors and protein levels.

METHODS

 Samples of human AM from thirteen donors were analysed. Collected donor data were age, parity and gestational age. Total protein amount was measured in extracts of intact AM nonpreserved, lyophilized and cryopreserved, at -80°C and in liquid nitrogen. An enzyme-linked immunosorbent assay (ELISA) was used to assay growth factors protein levels for epidermal growth factor, basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), transforming growth factor beta1 (TFG-β(1) ) and nerve growth factor (NGF). Univariate and multivariate statistical analyses were used to study the influence of the preservation method applied and interdonor variations on growth factors levels.

RESULTS

We detected important variations in growth factors and protein concentrations between samples from different donors. Total protein amount, bFGF, HGF, KGF and TGF-β(1) showed lower levels in samples from donors with higher gestational ages and donor ages, for all groups.

CONCLUSION

The variability in the biochemical composition of AM from different donors is considerable, and it is related with donor factors as donor age and gestational age. As AM biochemical composition has a role in its therapeutic effects, these variations could affect the clinical results of amniotic membrane transplantation and must be taken into account in donor selection processes.

Human amnion as a temporary biologic barrier after hysteroscopic lysis of severe intrauterine adhesions: pilot study

STUDY OBJECTIVE

To estimate the efficacy of fresh and dried amnion graft after hysteroscopic lysis of severe intrauterine adhesions in decreasing its recurrence and encouraging endometrial regeneration.

DESIGN

Pilot prospective randomized comparative study (Canadian Task Force classification I).

SETTING

Ain Shams Medical School, Cairo, Egypt.

PATIENTS

Forty-five patients with severe intrauterine adhesions. Primary symptom was infertility with or without menstrual disorders such as amenorrhea or hypomenorrhea.

INTERVENTIONS

Patients were randomized preoperatively using a computer-generated randomization sheet into 3 groups of 15 patients each. Allocation to any group was concealed in an opaque envelope, which was opened at the time of operation. Hysteroscopic lysis of intrauterine adhesions was followed by insertion of an intrauterine balloon only (group 1) or either fresh amnion graft (group 2) or dried amnion graft (group 3) for 2 weeks. Diagnostic hysteroscopy was performed at 2 to 4 months postoperatively.

MEASUREMENTS AND MAIN RESULTS

Adhesion grade, menstruation, uterine length, complications, and reproductive outcome were determined. There was significant improvement in adhesion grade with amnion graft vs intrauterine balloon alone (p = .003). Improvement was greater with fresh amnion than with dried amnion (p = .01). Normal menstruation occurred in 4 patients (28.6%) in group 1, 5 (35.7%) in group 2, and 7 (46.7%) in group 3. Of 43 patients, 41 (95.3%) were treated in 2 endoscopic sessions (95.3%), and 2 patients (4.7%) were treated in 3 endoscopic sessions. Uterine perforations occurred in 2 patients (4.7%), and cervical tears in 3 (7.0%). Ten patients (23.3%) achieved pregnancy, 8 (80%) after amnion graft and 2 (20%) without amnion. Six of the 10 patients (60%) miscarried, and 4 (40%) were either still pregnant or delivered at term without complications.

CONCLUSION

Hysteroscopic lysis of severe intrauterine adhesions with grafting of either fresh or dried amnion is a promising adjunctive procedure for decreasing recurrence of adhesions and encouraging endometrial regeneration.

Cartilage engineering using cell-derived extracellular matrix scaffold in vitro

A cell-derived extracellular matrix (ECM) scaffold was constructed using cultured porcine chondrocytes via a freeze-drying method, and its ability to promote cartilage formation was evaluated in vitro. Scanning electron microscope (SEM) revealed that the scaffold had highly uniform porous microstructure. Then, rabbit chondrocytes were seeded dynamically on ECM scaffold and cultured for 2 days, 1, 2, and 4 weeks in vitro for analysis. Polyglycolic acid (PGA) scaffold was used as a control. On gross observation of neocartilage tissue, a silvery white cartilage-like tissue was observed after 1 week of culture in ECM scaffold, while similar morphology was seen only after 4 weeks in PGA scaffold. The volume of neocartilage-like tissue was significantly increased in both ECM and PGA groups. The compressive strength was gradually increased with time in ECM group, while gradually decreased in PGA group. DNA, glycosaminoglycan (GAG) and collagen contents also increased gradually with time in both groups, but showed more significant increase in ECM group. Histological staining for GAG (Safranin O staining) and type II collagen (immunohistochemistry) showed sustained accumulation of ECM molecules with time, which gradually and uniformly filled porous space in ECM scaffold. On the contrary, they accumulated only at the peripheral area of PGA scaffold. These results suggest that a novel cell-derived ECM scaffold can provide a promising environment for generating a high quality cartilage in vitro.

Amniotic Membrane Transplantation for Repair of Leaking Glaucoma Filtering Blebs with Scleral Perforation

Leaking glaucoma filtering blebs with scleral perforation were successfully repaired in two patients using amniotic membrane transplantation. The amniotic membrane was placed into the subconjunctival space to cover the perforated scleral area. The edge of the limbal conjunctiva was sutured to the peripheral cornea with conjunctival advancement over the amniotic membrane. The bleb leaks were successfully closed. In addition, good and functioning filtration was maintained during a follow-up period of 12 months in both cases. Amniotic membrane transplantation may be effective for the surgical management of high risk of leaking glaucoma blebs with scleral perforation.

Management of acute Stevens-Johnson syndrome and toxic epidermal necrolysis utilizing amniotic membrane and topical corticosteroids

PURPOSE

To describe the results of a novel treatment approach to the acute ophthalmic management of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

DESIGN

Retrospective interventional case series.

METHODS

setting: Institutional. study population: Sixteen eyes of 8 patients with acute, biopsy-proven SJS or TEN and significant ophthalmic involvement. interventional procedure(s): Application of amniotic membrane to the ocular surface, either in the operating room or at the bedside, and short-term use of intensive topical corticosteroid medication. main outcome measures: Visual acuity, slit-lamp appearance of the ocular surface, and patients' subjective impression of ocular comfort.

RESULTS

Two patients expired during the hospitalization. Mean follow-up time for the surviving patients was 7.7 months. Four surviving patients in whom the entire ocular surface (ie, the cornea, bulbar and palpebral conjunctiva, and eyelid margins) was treated with amniotic membrane retained visual acuities of 20/40 or better and an intact ocular surface. In contrast, the initial 2 patients in the study who were treated with only a Prokera device or unsutured amniotic membrane sheets, leaving the palpebral conjunctiva and eyelid margins uncovered, developed more significant ocular surface abnormalities, and 1 developed a corneal perforation.

CONCLUSIONS

Amniotic membrane coverage of the ocular surface in its entirety coupled with the use of intensive short-term topical corticosteroids during the acute phase of SJS and TEN is associated with the preservation of good visual acuity and an intact ocular surface. Partial amniotic membrane coverage of the ocular surface may not serve to minimize the cicatrizing ocular sequelae of SJS and TEN as effectively as complete coverage.

Autologous serum 50% eyedrops in the treatment of persistent corneal epithelial defects

PURPOSE

To evaluate the success rate of treating persistent corneal epithelial defects using 50% autologous serum eyedrops.

METHODS

We reviewed the medical records of all patients seen at our institution from September 2004 to May 2007 who had persistent corneal epithelial defects that were nonresponsive to conventional medical treatment and that were treated with 50% autologous serum eyedrops. We also correlated the defect duration prior to initiation of serum therapy with rate of epithelial healing.

RESULTS

A total of 25 eyes of 25 patients failed conventional medical therapy for treatment of a persistent corneal epithelial defect and were treated with 50% autologous serum eyedrops every 2 hours while awake. All corneas were neurotrophic, with the etiologies being herpetic (11 eyes), postkeratoplasty (8 eyes), postkeratorefractive surgery (1 eyes), diabetic (1 eye), post-chemical burn (1 eye), and unknown (3 eyes). The median duration of the epithelial defects prior to initiation of autologous serum eyedrops was 13.9 weeks (range 0.29-52 weeks). After institution of autologous serum therapy, 23 of the 25 eyes healed in a mean time of 22.4 days. Seventeen eyes (68.0%) healed within 4 weeks (mean 1.7 weeks) of starting therapy with 50% autologous serum eyedrops. The number of days required for healing was associated with the length of time the defect was open prior to initiation of serum drops (r = 0.68, P < 0.001).

CONCLUSIONS

The use of 50% autologous serum eyedrops appears to be an efficacious medical treatment modality for persistent corneal epithelial defects that are recalcitrant to conventional medical therapy.

Amniotic membrane transplantation as a new therapy for the acute ocular manifestations of Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome and its more severe variant, toxic epidermal necrolysis, have relatively low overall incidence; however, this disease presents with high morbidity and mortality. The majority of patients develop ocular inflammation and ulceration at the acute stage. Due to the hidden nature of these ocular lesions and the concentration of effort toward life-threatening issues, current acute management has not devised a strategy to preclude blinding cicatricial complications. This review summarizes recent literature data, showing how sight-threatening corneal complications can progressively develop from cicatricial pathologies of lid margin, tarsus, and fornix at the chronic stage. It illustrates how such pathologies can be prevented with the early intervention of cryopreserved amniotic membrane transplantation to suppress inflammation and promote epithelial healing at the acute stage. Significant dry eye problems and photophobia can also be avoided with this intervention. This new therapeutic strategy can avert the catastrophic ophthalmic sequelae of this rare but devastating disease.

Evaluation of the role of ProKera in the management of ocular surface and orbital disorders

OBJECTIVES

To report the efficacy and safety profile of sutureless and adhesiveless amniotic membrane device (ProKera, Bio-Tissue, Inc., Miami, FL) in the management of various ocular surface and orbital disorders.

METHODS

Twenty eyes of 20 patients underwent placement of 21 ProKera implants between March 2006 and July 2007 at the University of Texas Southwestern Medical Center. Patient demographics, indications for placement, and duration of ProKera retention were recorded. Outcomes measured included corneal epithelial healing, visual acuity, patient tolerance, and adverse events.

RESULTS

ProKera was most commonly used in patients with corneal neovascularization with or without limbal stem-cell deficiency (10 eyes). Other indications included recurrent pterygium or pseudopterygium (three eyes), anophthalmic orbit contraction (two eyes), persistent epithelial defects (two eyes), severe thinning in a corneal ulcer (one eye), benign hereditary intraepithelial dyskeratosis (one eye), and band keratopathy (one eye). The mean duration of ProKera retention was 25.3 days (range, 0-125) visual acuity improved in 12 eyes (60%). Immediate adverse events included residual epithelial defects after removal (five eyes) and spontaneous extrusion of the implant (four eyes). Six patients (30%) reported eye pain or headache and four eyes (20%) had recurrence of the primary pathology.

CONCLUSIONS

Sutureless and adhesiveless amniotic membrane transplantation is a safe and effective method to promote healing and reconstruction of the ocular surface and orbit with minimal side effects. Recurrence of the underlying primary pathology remains a concern. The advent of a newer, softer conformer ring may improve patient tolerability and limit discomfort.

Preservation, sterilization and de-epithelialization of human amniotic membrane for use in ocular surface reconstruction

In the past 20 years, human amniotic membrane (AM) has become widely used as an ophthalmic surgical patch as well as a substrate for stem cell tissue equivalents for ocular surface reconstruction. AM reduces ocular surface scarring and inflammation, and enhances epithelialization. In addition, it shows limited immunogenicity and some anti-microbial properties. Before being applied clinically, the donor of AM is required to undergo a thorough health screening and the membrane has to undergo an accepted processing routine, which includes preservation, sterilization and de-epithelialization. There have been various articles describing methods in preserving, sterilizing and de-epithelializing AM. Each preparation technique has been reported to have differential effects on the physical and biological properties of the AM. Therefore, it is difficult to establish a standardized procedure. In this review, we discuss the present techniques and several novel, new approaches in the preparation of AM for use in ocular surface reconstruction, and their impact on AM structure and biological activity.

Transplantation of allogeneic and xenogeneic placenta-derived cells reduces bleomycin-induced lung fibrosis

Fetal membranes (amnion and chorion) have recently raised significant attention as potential sources of stem cells. We have recently demonstrated that cells derived from human term placenta show stem cell phenotype, high plasticity, and display low immunogenicity both in vitro and in vivo. Moreover, placenta-derived cells, after xenotransplantation, are able to engraft in solid organs including the lung. On these bases, we studied the effects of fetal membrane-derived cells on a mouse model of bleomycin-induced lung fibrosis. Fetal membrane-derived cells were infused 15 min after intratracheal bleomycin instillation. Different delivery routes were used: intraperitoneal or intratracheal for both xenogeneic and allogeneic cells, and intravenous for allogeneic cells. The effects of the transplanted cells on bleomycin-induced inflammatory and fibrotic processes were then scored and compared between transplanted and control animals at different time points. By PCR and immunohistochemistry analyses, we demonstrated the presence of transplanted cells 3, 7, 9, and 14 days after transplantation. Concomitantly, we observed a clear decrease in neutrophil infiltration and a significant reduction in the severity of bleomycin-induced lung fibrosis in mice treated with placenta-derived cells, irrespective of the source (allogeneic or xenogeneic) or delivery route. Our findings constitute further evidence in support of the hypothesis that placenta-derived cells could be useful for clinical application, and warrant further studies toward the use of these cells for the repair of tissue damage associated with inflammatory and fibrotic degeneration.

Comparison of cryopreserved and air-dried human amniotic membrane for ophthalmologic applications

BACKGROUND

Cryopreserved amniotic membrane (Cryo-AM) is widely used in ocular surface surgery because of its positive effect on wound healing and its anti-inflammatory properties. A new peracetic acid/ethanol sterilized air-dried amniotic membrane (AD-AM) recently became available which might be an alternative to Cryo-AM. Our aim was to compare AM preserved with both methods with regard to the release of wound-healing modulating proteins, the preservation of basement membrane components, and the ability to serve as a substrate for the cultivation of human limbal epithelial cells (HLECs).

METHODS

Pieces of Cryo-AM and AD-AM from three different donors were incubated in DMEM for five days. The culture supernatant was collected after an incubation period of 0.1, 24, 48, 72 and 120 h; in the case of AD-AM, this period was extended up to 14 days. TIMP-1, IL-1ra, CTGF and TGF-beta1 were detected in the culture supernatant using Western blotting. Twenty human limbal epithelial cultures were initiated on both AD- and Cryo-AM. The cultures were analyzed morphologically, and the outgrowth area was measured in 3-day intervals. Cryosections of Cryo- and AD-AM from three different donors were analyzed histochemically to detect the basement membrane components collagen IV, collagen VII, laminin, laminin 5 and fibronectin.

RESULTS

The release of TIMP-1, IL-1ra and TGF-beta1 from Cryo-AM was constant for the studied period. CTGF showed a stronger signal after 120 h. None of the analyzed proteins, except for a small amount of IL-1ra, could be detected in the supernatant of AD-AM. An outgrowth of HLEC was observed in all cultures on Cryo-AM, but in only 30% of cultures on AD-AM. The outgrowth area on Cryo-AM was at all time points significantly higher than on AD-AM (p < 0.0001). Collagen IV, -VII, laminins and fibronectin were detectable in the basement membrane of Cryo-AM, but only collagen IV and fibronectin in AD-AM.

CONCLUSIONS

Cryo-AM is a more suitable substrate for the cultivation of HLECs than AD-AM. The higher outgrowth rate of cultured limbal epithelium, release of intact soluble wound-healing modulating factors and a better preservation of basement membrane components suggest the superiority of Cryo-AM for use in ophthalmology in comparison to AD-AM.

Effects of amniotic membrane on the healing of normal and high-risk colonic anastomoses in rats

BACKGROUND

This study was aimed at examining whether or not the addition of amniotic membrane to a sutured colonic anastomosis improves its healing.

MATERIAL AND METHODS

Ninety female Sprague Dawley rats were used in the study. Ten served as controls for bursting pressure measurement, while the other 80 animals were divided into four groups: Anastomosis group (NA), high-risk anastomosis group (HRA), anastomosis plus amniotic membrane group (NA-AM), and high-risk anastomosis plus amniotic membrane group (HRA-AM). The last two groups had amniotic membrane covering their anastomoses. Anastomotic evaluation was carried out on the third (NA3, HRA3, NA-AM3, and HRA-AM3, respectively) and seventh (NA7, HRA7, NA-AM7, and HRA-AM7, respectively) postoperative days. The main outcome measures were gross anastomotic healing, adhesion formation, mechanical strength, hydroxyproine content, and parameters of histopathological healing.

RESULTS

Anastomotic dehiscence rate was 66.7%, 40%, 20%, and 10% in group HRA7, HRA3, NA7, and NA3, respectively. However, there was no significant difference between groups regarding the dehiscence rate. The adhesion scores were significantly higher in groups NA3 and HRA3 compared with groups NA-AM3 and HRA-AM3, respectively (p < 0.05, p < 0.001). Bursting pressure was significantly higher in groups with amniotic membrane compared without amniotic membrane (p < 0.05, for all comparison). Inflammatory cell infiltration was significantly lower in groups with amniotic membrane compared with groups without amniotic membrane (p < 0.05, for all both comparisons). Neoangiogenesis was significantly higher in the NA-AM3 and HRA-AM3 groups compared with the NA3 (p < 0.01) and HRA3 (p < 0.05) groups, respectively. Fibroblast activity was significantly higher in groups NA-AM3 and NA-AM7 compared with groups NA3 (p < 0.05) and NA7 (p < 0.05), respectively. Collagen deposition and hydroxyproline concentrations were significantly higher in groups with amniotic membrane compared with groups without amniotic membrane (p < 0.05, for all both comparisons).

CONCLUSION

The covering of both normal and high-risk colonic anastomoses with amniotic membrane provides a beneficial effect over conventional suturing of healing.

Effects of lyophilization on human amniotic membrane

PURPOSE

This study aimed to evaluate the effects of lyophilization and cryopreservation on human amniotic membrane (HAM) in terms of histological characteristics and growth factor levels.

METHODS

Non-preserved, lyophilized and cryopreserved HAM samples from 13 placentas were investigated. The morphological characteristics of HAM were evaluated using light and electron microscopy. Immunohistochemical methods were also applied to assess the distribution of collagen IV in the basement membrane. Total protein amounts were measured in extracts of intact amniotic membrane from non-preserved, lyophilized and cryopreserved samples. An enzyme-linked immunosorbent assay (ELISA) was used to assay growth factor protein levels for epidermal growth factor, fibroblast growth factor basic, hepatocyte growth factor, keratinocyte growth factor, transforming growth factor-beta1 and nerve growth factor.

RESULTS

Histological examination of lyophilized and cryopreserved human amniotic membrane showed similar results. Immunohistochemistry showed presence of collagen IV throughout the basement membrane, both in cryopreserved and lyophilized samples. Total protein amount was higher in cryopreserved samples, without statistical significance. Growth factors ELISA did not show statistically significant differences except for fibroblast growth factor basic, with higher levels in cryopreserved amniotic membrane.

CONCLUSIONS

Lyophilization maintains the histological structure of HAM, but seems to cause greater reductions in total protein amount and growth factor concentration than cryopreservation.

Repair of oronasal fistulas with human amniotic membrane in minipigs

We evaluated the use of multilayer human amniotic membrane (HAM) as a grafting material for the repair of mid-palate oronasal fistulas in seven Berlin minipigs. After two weeks, three animals had the fistulas repaired with multilayered HAM grafts, three had them repaired with a collagen-based dermal substitute (INTEGRA((R)), Integra Life Sciences, Plainsboro, NJ, USA), and one fistula was left untreated to serve as a control. Grafts were interposed between the oral and nasal mucosa, traversing the fistulas. After healing for 40 days, the pigs were killed for clinical, histological, and immunohistochemical examination. Two of the three fistulas closed with HAM were successful, the diameter of the third was reduced in size, and there was no change in the diameter of the fistula in the control. This study shows successful closure of oronasal fistulas in minipigs using interposed grafts of cryopreserved HAM, and offers promise as a simple and effective technique for tension-free closure of such fistulas.

In vitro eye irritancy test of polyoxyethylene alkyl derivatives using a reconstructed rabbit corneal epithelium model

We have developed the Rabbit Corneal Epithelial (RCE) Model to evaluate the in vitro eye irritation potential of chemicals including pharmaceuticals, cosmetics and their raw ingredients. In the model, a stratified culture of rabbit corneal epithelial cells is grown at the air-liquid interface on an amnion acting as a parabasal membrane. The alkaline exposure was restored each day in the presence of no irritants, although with the addition of sodium lauryl sulfate (SLS), which is a major irritant, the restoration of deficit was inhibited on the RCE model in a dose-dependent manner. The results of this test were comparable with those of the Draize test, and thus, this method using the RCE model may prove to be a useful and sensitive in vitro eye irritation test. The in vitro eye irritation potential of polyoxyethylene alkyl derivatives, polyoxyethylene lauryl ether (PLE), polyoxyethylene cetyl ether (PCE), polyoxyethylene stearyl ether (PSE), polyoxyethylene oleyl ether (POE), and polyoxyethylene behenyl ether (PBE) were evaluated using the RCE model containing an alkaline exposure. POE inhibited 90.2% of the restoration of deficit at a concentration of 0.5% on the 4th day after addition. Depending on the structure, an activity relationship was defined. The polyoxyethylene alkyl derivatives had distinctly different inhibitory potencies against the restoration of deficit, according to their substitution patterns. POE inhibited the restoration of deficit greater than other polyoxyethylene alkyl derivatives on the RCE model. These results indicated that the oleyl chain of POE is an important factor for inhibiting the restoration of deficit on the RCE model.