Molecular mechanism of fluoroquinolones modulation on corneal fibroblast motility

Does Topical Steroid Use Increase the Risk for Subsequent Tympanoplasty?

OBJECTIVES

Although the current data support the notion that combination therapy of topical steroids with antibiotics is a safe, and often superior, option for suppurative otitis media when compared to topical antibiotics alone, little is known about the impact of topical steroids on tympanic membrane (TM) healing and risk of residual perforation. This study aims to describe the long-term impact the addition of topical steroids to antibiotics has on TM healing, as measured by rates of subsequent tympanoplasty.

METHODS

Electronic health records were queried using TriNetX Research Network to construct cohorts of adult patients with "infected" TM perforation (ICD-10 code H66) and "noninfected" TM perforation (ICD-10 code H72). Both groups were further divided based on treatment with ofloxacin or ciprofloxacin/dexamethasone (RxNorm codes). The measured outcome was whether or not the patient underwent tympanoplasty without mastoidectomy or ossicular reconstruction within 2 years following diagnosis and treatment.

RESULTS

In "infected" patients, the ciprofloxacin/dexamethasone cohort demonstrated a small but significantly increased risk of undergoing tympanoplasty (1.12%) compared to the ofloxacin cohort (0.76%, p < 0.05). In "noninfected" patients, the ciprofloxacin/dexamethasone cohort demonstrated a significantly increased risk of undergoing tympanoplasty (6.87%) compared to the ofloxacin cohort (5.67%, p < 0.05).

CONCLUSION

In the setting of acute suppurative otitis media, there is a small but statistically significant increased risk of residual TM perforation when patients receive ciprofloxacin/dexamethasone compared to ofloxacin. However, the clinical significance of this risk must be weighed against the curative and symptomatic benefits of ciprofloxacin/dexamethasone over ofloxacin.

Construction of living-cell tissue engineered amniotic membrane for ocular surface disease

BACKGROUND

Human amniotic membrane (AM) transplantation has been applied to treat ocular surface diseases, including corneal trauma. The focus of much deliberation is to balance the mechanical strength of the amniotic membrane, its resistance to biodegradation, and its therapeutic efficacy. It is commonly observed that the crosslinked human decellularized amniotic membranes lose the functional human amniotic epithelial cells (hAECs), which play a key role in curing the injured tissues.

METHODS AND RESULTS

In this study, we crosslinked human decellularized amniotic membranes (dAM) with genipin and re-planted the hAECs onto the genipin crosslinked AM. The properties of the AM were evaluated based on optical clarity, biodegradation, cytotoxicity, and ultrastructure. The crosslinked AM maintained its transparency. The color of crosslinked AM deepened with increasing concentrations of genipin. And the extracts from low concentrations of genipin crosslinked AM had no toxic effect on human corneal epithelial cells (HCECs), while high concentrations of genipin exhibited cytotoxicity. The microscopic observation and H&E staining revealed that 2 mg/mL genipin-crosslinked dAM (2 mg/mL cl-dAM) was more favorable for the attachment, migration, and proliferation of hAECs. Moreover, the results of the CCK-8 assay and the transwell assay further indicated that the living hAECs' tissue-engineered amniotic membranes could facilitate the proliferation and migration of human corneal stromal cells (HCSCs) in vitro.

CONCLUSIONS

In conclusion, the cl-dAM with living hAECs demonstrates superior biostability and holds significant promise as a material for ocular surface tissue repair in clinical applications.

A single chain variable fragment antibody (Tn 64) cognate to fibronectin type III repeats promotes corneal wound healing by inhibiting fibrosis

Corneal wound healing requires epithelial reorganization and stromal extracellular matrix (ECM) remodeling, with ECM proteins such as Tenascin C (TnC) regulating and maintaining corneal homeostasis. The N-terminal globular domain and C-terminal fibrinogen-related domains of TnC are separated by epidermal growth factor (EGF)-like repeats, and upto fifteen fibronectin type III domains (Tn fn). Overexpression of Tn fn 1-5 and its splice variants occurs in varied pathologies. We have previously used Tn64 (a single chain variable fragment antibody cognate to Tn fn 1-5) to establish roles of Tn fn 1-5 in fibrotic pathologies such as rheumatoid arthritis and posterior capsular opacification. Here, we show that Tn64 binds to Tn fn repeats 3-5 (which constitute the major site for binding of soluble fibronectin within TnC). Unlike other Tn fn domains, Tn fn 3-5 displays no inhibition of fibronectin matrix assembly. Rather, the Tn fn 3-5 construct is pro-fibrotic and elicits increased expression of fibronectin. We examined corneal epithelial as well as stromal wound healing through Tn64 binding to Tn fn 3-5, using a human corneal epithelial cell (HCEC) line, primary cultures of human corneal fibroblasts (HCFs), and an ex-vivo corneal organ culture model. Tn64 enhanced proliferation and adhesion of corneal epithelial cells, while inhibiting the migration of corneal fibroblasts and myofibroblasts. Tn64 appears to attenuate inflammation through downregulation of TNF-α, prevent corneal fibrosis by limiting fibronectin polymerization, and promote regeneration of corneal epithelia and stroma, suggesting that it could be developed as a therapeutic agent for effective anti-fibrotic corneal wound healing.

Ionic complexation improves wound healing in deep second-degree burns and reduces in-vitro ciprofloxacin cytotoxicity in fibroblasts

The development of new treatments capable of controlling infections and pain related to burns continues to be a challenge. Antimicrobials are necessary tools, but these can be cytotoxic for regenerating cells. In this study, antibiotic-anesthetic (AA) smart systems obtained by ionic complexation of polyelectrolytes with ciprofloxacin and lidocaine were obtained as films and hydrogels. Ionic complexation with sodium alginate and hyaluronate decreased cytotoxicity of ciprofloxacin above 70% in a primary culture of isolated fibroblasts (p < 0.05). In addition, the relative levels of the proteins involved in cell migration, integrin β1 and p-FAK, increased above 1.5 times (p < 0.05) with no significant differences in cell mobility. Evaluation of the systems in a deep second-degree burn model revealed that reepithelization rate was AA-films = AA-hydrogels > control films > no treated > reference cream (silver sulfadiazine cream). In addition, appendage conservation and complete dermis organization were achieved in AA-films and AA-hydrogels. Encouragingly, both the films and the hydrogels showed a significantly superior performance compared to the reference treatment. This work highlights the great potential of this smart system as an attractive dressing for burns, which surpasses currently available treatments.

Moxifloxacin induces random migration in human corneal fibroblasts via the protein kinase C epsilon/zonula occludens-1 signaling pathway

Moxifloxacin (MOX) suppresses cell movement in human corneal fibroblasts (HCFs). Zonula occludens-1 (ZO-1) is localized to the leading edge of migrating HCFs. This study explored the role of ZO-1 in MOX-suppressed cell migration in HCFs. A single-cell trajectory analysis revealed that MOX negatively regulated the migratory properties of HCFs including migration distance, migration velocity, and directionality (P < 0.001, P < 0.001, and P = 0.018, respectively). MOX increased endogenous ZO-1 in HCFs in a concentration-dependent manner (P = 0.083, P = 0.005, and P = 0.001 at 10, 50, and 100 μg/ml, respectively), but decreased the phosphorylation of endogenous ZO-1 at serines, threonines, and tyrosines. In contrast, MOX did not alter the expression of protein kinase C epsilon (PKCε), Rac-1, Cdc42, and MRCKβ. However, MOX did also reduce the phosphorylation level of PKCε at serines and threonines (P < 0.001 at 100 μg/ml). In addition, MOX increased the phosphorylation level of Rac-1 in a concentration-dependent manner (P < 0.001 at 100 μg/ml). Compared with the mock cells, the directionality of cell movement increased significantly in ZO-1-expressing HCFs (P = 0.012) and decreased significantly in ZO-1-silenced HCFs (P = 0.002). The directionality did not change significantly in Rac-1-silenced HCFs. ZO-1-expressing HCFs moved faster than mock cells. PKCε, Cdc42, Rac-1, and phosphorylated Rac-1 were decreased in ZO-1-overexpressing HCFs, but increased in ZO-1-silenced HCFs. Finally, silencing ZO-1 blocked MOX hyperactivation of Rac-1. These suggest that MOX might trigger random migration in human corneal stromal cells through PKCε-modulated ZO-1 inactivation and Rac-1 hyperactivation.

Development of a dual delivery of levofloxacin and prednisolone acetate via PLGA nanoparticles/ thermosensitive chitosan-based hydrogel for postoperative management: An in-vitro and ex-vivo study

Post-operative endophthalmitis (POE) is one of the most dreadful complications after intraocular surgery. For cataract surgery patients, both commercially available topical 0.5% levofloxacin and 1% prednisolone acetate (PA) ophthalmic solution require at least 3 to 4 times application daily. In this study, we develop a dual drug delivery system composed of the thermosensitive chitosan/gelatin-based hydrogel containing PA and levofloxacin-loaded nanoparticles (LNPs). LNPs with negative surface charge show the monodisperse (polydispersity index ~0.045), nanosize (~154.7 nm) and sphere-like structure. The optimal concentration of LNPs and PA to corneal epithelial cells was 5 μg/mL and 50 μg/mL, respectively. The developed dual drug delivery system (PAgel-LNPs) could gel at 34 °C within 63 s. The osmolarity of PAgel-LNPs was 301.2 ± 1.5 mOsm/L. PAgel-LNPs showed a sustained-release profile for 7 days. Post-treatment of PAgel-LNPs in TNF-α-damaged corneal epithelial cells could decrease the inflammation (inflammatory genes (TNF-α, IL-6, MMP-3 andMMP-9) and IL-6 production) and cell death. In ex-vivo rabbit model of S. aureus keratitis, the anti-inflammation and anti-bacterial property have been demonstrated. These results suggest that thermosensitive PAgel-LNPs may have the potential to use for the prevention of POE.

Mitomycin C modulates intracellular matrix metalloproteinase-9 expression and affects corneal fibroblast migration

Mitomycin C (MMC) is often used to prevent postoperative corneal haze and subconjunctival fibrosis in ocular surgery. It also affects the motility and viability of the residual ocular cells, including corneal stromal cells. Extracellular matrix metalloproteinase-9 (MMP-9) contributes to the promotion of cell movement in macrophage and cancer cells, but the intracellular role of MMP-9 remained unclear. Herein, we illustrated the novel role of intracellular MMP-9 in MMC-suppressed cell migration using isolated human corneal fibroblasts (HCFs). In HCFs, MMC enhanced intracellular MMP-9 at transcriptional and protein levels. Using co-immunoprecipitation analysis, we confirmed that MMC enhanced the association between intracellular MMP-9 and inactive FAK/paxillin (PXN) complexes, i.e. PXN without phospho-tyrosine 118 (pY118) and FAK without phospho-tyrosine 397 (pY397). To verify the role of intracellular MMP-9 in migration, its gene was directly isolated from HCFs and highly expressed in HCFs by a lentivirus-based pseudovirus system with encephalomyocarditis virus (EMCV)-driven enhanced green fluorescent protein (GFP) as the MMP-9-IG-versus IG-expressing cells. Compared with the IG-expressing cells, higher intracellular MMP-9 expression in the MMP-9-IG-expressing HCFs proliferated and migrated more slowly. Phosphorylation of FAK at Y397 and PXN at both Y31 and Y118 were significantly less in the MMP-9-IG-expressing HCFs. These suggested that MMC-upregulated intracellular MMP-9 clutched inactive FAK/PXN complexes at focal adhesion sites to form a new "inactive" trimer, prohibited FAK/PXN complexes phosphorylation and retarded corneal fibroblast migration.

Axitinib inhibits retinal and choroidal neovascularization in in vitro and in vivo models

Age-related Macular Degeneration (AMD) is the leading cause of visual impairment and blindness in the elderly in developed countries. Neovascular/exudative (wet) AMD is the aggressive form of AMD and can involve choroidal neovascularization and vascular leakage. Anti-vascular endothelial growth factor (anti-VEGF) medications have significantly improved treatment of wet-AMD. However, only approximately 40% of patients obtain full benefit from anti-VEGF therapy and the medications are given by intravitreal injection. Axitinib, a small molecule multi-receptor tyrosine kinase inhibitor used for the treatment of advanced renal cell carcinoma, is taken orally and inhibits VEGF activity by blocking VEGF receptors. Axitinib also has the advantage of blocking platelet derived growth factor (PDGF) receptors which play a role in neovascularization. Using in vitro human retinal microvascular endothelial cells (HRMVECs), human brain vascular pericytes (HBVRs), 3D co-culture vessel sprout assay, and in vivo laser induced rat choroidal neovascularization (CNV) models, the effect of axitinib on neovascularization was evaluated. Axitinib inhibited neovascularization better than anti-VEGF and/or anti-hPDGF-B mAb in the in vitro models demonstrating that combined inhibition of both VEGF and PDGF pathways may be synergistic in treating wet-AMD. Additionally, axitinib showed good efficacy at a low dose (0.875 mg/day) in laser-induced CNV model in rats. In conclusion our data shows that axitinib, an inhibitor of VEGF and PDGF-B pathways may be useful in ameliorating wet-AMD therapy.