Lidocaine effects on corneal endothelial cell ultrastructure

Effects of ophthalmic surface anesthetic alcaine on the proliferation and apoptosis of human corneal endothelial cells through HIF-1α regulation

The corneal endothelium is a monolayer, which mediates solute and water flux across the posterior corneal surface. Alcaine's main component proparacaine is paramount in human corneal endothelium (HCE) cell regulation. This study explored the mechanism of alcaine in regulating HCE cells. HCE cell morphology under gradient concentrations was observed by an optical microscope. Cell proliferation and viability were detected by MTT assay to determine the half inhibitory concentration (IC 50). Cell apoptosis rate, HIF-1α mRNA expression, and HIF-1α, p/t-JNK and Caspase-3 protein levels were detected by flow cytometry, RT-qPCR, and Western blot. After treatment with alcaine at 0.625-5 g/L concentration range for 24 h, HCE cells showed cytoplasmic vacuolation, cell shrinkage, separation from culture matrix, and eventual death. Alcaine treated-HCE cell proliferation was decreased in a dose-dependent manner. The IC 50 of alcaine was 1.26 g/L. After alcaine treatment, HCE cell apoptosis rate was promoted and HIF-1α levels in HCE cells were stimulated. Knockdown of HIF-1α partially annulled the effects of alcaine on inhibiting HCE cell proliferation and facilitating apoptosis. Alcaine might activate the JNK/caspase-3 pathway by increasing HIF-1α. The inhibition of the JNK/caspase-3 pathway partially abrogated the effects of alcaine on inhibiting HCE cell proliferation and promoting apoptosis. Alcaine might affect HCE cell proliferation and apoptosis by upregulating HIF-1α and activating the JNK/caspase-3 pathway.

Sodium Ferulate Attenuates Lidocaine-Induced Corneal Endothelial Impairment

The introduction of intracameral anaesthesia by injection of lidocaine has become popular in cataract surgery for its inherent potency, rapid onset, tissue penetration, and efficiency. However, intracameral lidocaine causes corneal thickening, opacification, and corneal endothelial cell loss. Herein, we investigated the effects of lidocaine combined with sodium ferulate, an antioxidant with antiapoptotic and anti-inflammatory properties, on lidocaine-induced damage of corneal endothelia with in vitro experiment of morphological changes and cell viability of cultured human corneal endothelial cells and in vivo investigation of corneal endothelial cell density and central corneal thickness of cat eyes. Our finding indicates that sodium ferulate from 25 to 200 mg/L significantly reduced 2 g/L lidocaine-induced toxicity to human corneal endothelial cells, and 50 mg/L sodium ferulate recovered the damaged human corneal endothelial cells to normal growth status. Furthermore, 100 mg/L sodium ferulate significantly inhibited lidocaine-induced corneal endothelial cell loss and corneal thickening in cat eyes. In conclusion, sodium ferulate protects human corneal endothelial cells from lidocaine-induced cytotoxicity and attenuates corneal endothelial cell loss and central corneal thickening of cat eyes after intracameral injection with lidocaine. It is likely that the antioxidant effect of sodium ferulate reduces the cytotoxic and inflammatory corneal reaction during intracameral anaesthesia.

Cytotoxicity of lidocaine to human corneal endothelial cells in vitro

Lidocaine has been reported to induce apoptosis on rabbit corneal endothelial cells. However, the apoptotic effect and exact mechanism involved in cytotoxicity of lidocaine are not well-established in human corneal endothelial (HCE) cells. In this study, we investigated the apoptosis-inducing effect of lidocaine on HCE cells in vitro. After HCE cells were treated with lidocaine at concentrations of 0.15625-10.0 g/l, the morphology and ultrastructure of the cells were observed by inverted light microscope and transmission electron microscope (TEM). Cell viability was measured by MTT assay, and the apoptotic ratio was evaluated with flow cytometry and fluorescent microscopic counting after FITC-Annexin V/PI and AO/EB staining. DNA fragmentation was detected by electrophoresis, and the activation of caspases was evaluated by ELISA. In addition, changes in mitochondrial membrane potential were determined by JC-1 staining. Results suggest that lidocaine above 1.25 g/l reduced cellular viability and triggered apoptosis in HCE cells in a time- and dose-dependent manner. Diminishment of ΔΨm and the activation of caspases indicate that lidocaine-induced apoptosis was caspase dependent and may be related to mitochondrial pathway.

Viscoat versus Visthesia during phacoemulsification cataract surgery: corneal and foveal changes

Background

Ophthalmic viscosurgical devices (OVDs) are widely used in phacoemulsification cataract surgery to maintain adequate intraocular space, stabilize ocular tissue during the operation and decrease the possible damage of the corneal endothelium. Our study has the purpose to compare the corneal and foveal changes of Viscoat and Visthesia in patients undergoing uneventful phacoemulsification cataract surgery.

Methods

Participants in our study were 77 consecutive patients, who were randomized into two groups based on type of OVD used during phacoemulsification: Viscoat or Visthesia. All patients underwent a complete ophthalmological examination i.e., measurement of best corrected visual acuity (BCVA) by means of Snellen charts, intraocular pressure examination by Goldmann tonometry, slit lamp examination, fundus examination, optical coherence tomography, specular microscopy and ultrasound pachymetry preoperatively and at three time points postoperatively (day 3, 15, 28 postoperatively). The differences in baseline characteristics, as well as in outcomes between the two groups were compared by Mann-Whitney-Wilcoxon test and Student's t-test, as appropriate.

Results

Intraoperatively, there was no statistically significant difference in the duration of the ultrasound application between the two groups, while Viscoat group needed more time for the operation performance. It is also worthy to mention that Visthesia group exhibited less intense pain than patients in Viscoat group. Postoperatively, there was a statistically significant difference in central corneal thickness, endothelial cell count and macular thickness between the two groups, but BCVA (logMAR) did not differ between the two groups.

Conclusions

Our study suggests that Viscoat is more safe and protective for the corneal endothelium during uneventful phacoemulsification cataract surgery, while Visthesia is in superior position regarding intraoperative pain. Patients of both groups acquired excellent visual acuity postoperative. Finally, this is the first study comparing OVDs in terms of macular thickness, finding that Visthesia cause a greater increase in macular thickness postoperatively than Viscoat, although it reaches normal ranges in both groups.

Safety, efficacy, and patient acceptability of lidocaine hydrochloride ophthalmic gel as a topical ocular anesthetic for use in ophthalmic procedures

Purpose:

To review the current literature on safety, efficacy, and measures of surgeon and patient satisfaction with lidocaine hydrochloride gel as a tool for ocular anesthesia.

Methods:

Pubmed search using keywords “lidocaine gel,” “ophthalmic,” and “surgery” and compiling cross-references. Twenty-six total references were reviewed, including 15 prospective randomized controlled trials (RCTs, total N = 933, average N = 62), 6 nonrandomized prospective studies (total N = 234, average N = 39), 2 animal studies, 1 microbiologic study, and 2 letters to the editor.

Results:

The RCTs and nonrandomized prospective studies evaluated a number of measures including timing of onset of anesthesia, duration of anesthesia, intraoperative and postoperative pain, need for additional anesthetic applications, intracameral lidocaine levels, and adverse effects. Control groups received topical drops, subconjunctival anesthetic, retrobulbar anesthetic, or sham gel. Lidocaine gel was shown to be at least as effective for pain control as alternative therapies in all studies, with longer duration of action than topical drops. Patient and surgeon satisfaction were high, and adverse effects were rare and comparable to those for anesthetic drop formulations. Surgical settings included cataract, pterygium, trabeculectomy, strabismus, intravitreal injection, vitrectomy, and penetrating keratoplasty.

Conclusions:

Lidocaine gel is a safe, effective, and potentially underutilized tool for ophthalmic surgery.