Burn Scar Ectropion Correction: Surgical Technique for Functional Outcomes.

BACKGROUND: Eyelid scarring after severe burn injury of the face is a significant complication endangering vision in addition to the burn scar sequelae. Scar contraction leads to asymmetry and malposition of the eyelid axis, resulting in corneal exposure, eyelid retraction, and incomplete eyelid closure. In consequence, dryness and irritation of the cornea can lead to keratitis, corneal opacity, and vision impairment. In this study, we present our surgical technique for lateral canthopexy in combination with full-thickness skin grafting (FTSGing) in patients with eyelid axis distortion after scar contraction of the periorbital region after severe burn injuries of the face. METHODS: In this retrospective, single-center case study, we present 5 consecutive patients who experienced severe burn injuries to the face between 2014 and 2019. Patients were suffering from ectropion and malposition of the eyelid axis. In all cases, we performed lateral transosseous canthopexy and FTSGing. RESULTS: Improved symmetry and complete eyelid closure were restored in all 5 patients. The following ophthalmological examinations showed resolved corneal erosions, as well as reduction of chemosis and epiphora. Further vision impairment was successfully prohibited. Surgical revision with FTSGing was required in 2 patients because of recurrence of unilateral lower eyelid retraction. CONCLUSIONS: Lateral transosseous canthopexy represents a suitable surgical method to durably correct eyelid malposition, ectropion, and incomplete lid closure in patients with severe scarring of the periorbital region after burns of the face. Early detection of patients at risk and timing of surgical intervention are of great importance.

Phototherapy with UVB narrowband, UVA/UVBnb, and UVA1 differentially impacts serum 25-hydroxyvitamin-D3.

BACKGROUND: Ultraviolet (UV) B radiation increases serum 25-hydroxyvitamin-D3 [25(OH)D], but the influence of UVA1 and UVA/narrowband UVB (UVBnb) phototherapy on serum vitamin D is unknown. OBJECTIVE: We sought to investigate the influence of UVBnb, UVA1, and UVA/UVBnb phototherapy on serum levels of 25(OH)D and related parameters in patients with an inflammatory skin condition. METHODS: 25(OH)D, as well as calcium, parathormone, phosphate, and albumin were measured before therapy, 2 weeks after start, and after completion of the phototherapy. Diagnoses were divided in 4 groups: atopic dermatitis, psoriasis, morphea, and others. RESULTS: We surveyed 116 dermatologic patients undergoing phototherapy with UVA1 (n = 38), UVA/UVBnb (n = 30), or UVBnb (n = 48) 2 to 3 times a week for 53 to 90 days. UVBnb phototherapy increased serum 25(OH)D from 22.1 to 39.5 ng/mL after the therapy (P < .001). The lower the baseline 25(OH)D level was, the steeper the increase in 25(OH)D was upon application of UVBnb phototherapy. UVA/UVBnb therapy also increased serum 25(OH)D, from 23.9 to 50.3 ng/mL (P = .003). Conversely, in the UVA1 therapy group, 25(OH)D serum levels decreased significantly from 21.9 to 19.0 ng/mL (P < .001). LIMITATIONS: The study design was open trial without randomization. An influence of a precise skin disease cannot be excluded because of the heterogeneous diagnoses. Bias may have arisen from patient preference for treatment at our center, referral, unrecognized differences in underlying skin disease, and other factors. CONCLUSION: Phototherapy with UVBnb and UVA/UVBnb increased 25(OH)D serum level significantly. UVA1 therapy alone induced a reduction in serum 25(OH)D concentrations.

Mesenchymal Stem Cells Reduce Corneal Fibrosis and Inflammation via Extracellular Vesicle-Mediated Delivery of miRNA.

Mesenchymal stem cells from corneal stromal stem cells (CSSC) prevent fibrotic scarring and stimulate regeneration of transparent stromal tissue after corneal wounding in mice. These effects rely on the ability of CSSC to block neutrophil infiltration into the damaged cornea. The current study investigated the hypothesis that tissue regeneration by CSSC is mediated by secreted extracellular vesicles (EVs). CSSC produced EVs 130-150 nm in diameter with surface proteins that include CD63, CD81, and CD9. EVs from CSSC reduced visual scarring in murine corneal wounds as effectively as did live cells, but EVs from human embryonic kidney (HEK)293T cells had no regenerative properties. CSSC EV treatment of wounds decreased expression of fibrotic genes Col3a1 and Acta2, blocked neutrophil infiltration, and restored normal tissue morphology. CSSC EVs labeled with carboxyfluorescein succinimidyl ester dye, rapidly fused with corneal epithelial and stromal cells in culture, transferring microRNA (miRNA) to the target cells. Knockdown of mRNA for Alix, a component of the endosomal sorting complex required for transport, using siRNA, resulted in an 85% reduction of miRNA in the secreted EVs. The EVs with reduced miRNA were ineffective at blocking corneal scarring. Furthermore, CSSC with reduced Alix expression also lost their regenerative function, suggesting EVs as an obligate component in the delivery of miRNA. The results of these studies support an essential role for extracellular vesicles in the process by which CSSC cells block scarring and initiate regeneration of transparent corneal tissue after wounding. EVs appear to serve as a delivery vehicle for miRNA, which affects the regenerative action. Stem Cells Translational Medicine 2019;8:1192-1201.

Compressed Collagen Enhances Stem Cell Therapy for Corneal Scarring.

Stem cells from human corneal stroma (CSSC) suppress corneal stromal scarring in a mouse wound-healing model and promote regeneration of native transparent tissue (PMID:25504883). This study investigated efficacy of compressed collagen gel (CCG) as a vehicle to deliver CSSC for corneal therapy. CSSC isolated from limbal stroma of human donor corneas were embedded in soluble rat-tendon collagen, gelled at 37°C, and partially dehydrated to a thickness of 100 µm by passive absorption. The CCG disks were dimensionally stable, easy to handle, and could be adhered securely to de-epithelialized mouse cornea with fibrin-based adhesive. CSSC in CCG maintained >80% viability for >1 week in culture media and could be cryopreserved in 20% fetal bovine serum-10%DMSO in liquid nitrogen. CCG containing as few as 500 CSSC effectively prevented visible scarring and suppressed expression of fibrotic Col3a1 mRNA. CSSC in CCG were more effective at blocking scarring on a per-cell basis than CSSC delivered directly in a fibrin gel as previously described. Collagen-embedded cells retained the ability to suppress corneal scarring after conventional cryopreservation. This study demonstrates use of a common biomaterial that can facilitate storage and handling of stem cells in a manner that may provide off-the-shelf delivery of stem cells as a therapy for corneal scarring. Stem Cells Translational Medicine 2018;7:487-494.

Corneal stromal stem cells reduce corneal scarring by mediating neutrophil infiltration after wounding.

Corneal scarring limits vision for millions of individuals worldwide. Corneal transplantation (keratoplasty) is the standard of care for corneal opacity; however, it bears the risk of graft rejection and infection and is not universally available. Stem cell therapy holds promise as an alternative to keratoplasty. Stem cells from human corneal stroma (CSSC) induce regeneration of transparent corneal tissue in a mouse wound-healing model. In this study we investigated the mechanism by which CSSC prevent deposition of fibrotic tissue. Infiltration by CD11b+/Ly6G+ neutrophils and myeloperoxidase expression were increased in corneas 24 hr after corneal wounding but were reduced in CSSC-treated wounds. Secretion of TSG-6, a protein known to regulate neutrophil migration, was up-regulated in CSSC in response to TNFα and as CSSC differentiate to keratocytes. In vivo, wounded mouse corneas treated with CSSC contained human TSG-6. Inhibition of neutrophil infiltration into cornea by CSSC was reversed when TSG-6 expression was knocked down using siRNA. Silencing of TSG-6 expression in CSSC reduced their ability to block scarring and the expression of mRNA for fibrosis-associated proteins collagen III, tenascin C, and smooth muscle actin in wounded corneas. Neutropenic mice exhibited a significant reduction in corneal scarring and fibrotic mRNA expression 2 weeks after wounding. These results support the conclusion that neutrophil infiltration is an essential event in the fibrotic response to corneal damage and that prevention of scarring by CSSC is mediated by secretion of TSG-6 by these cells.