Effects of nicotine on corneal wound healing following acute alkali burn

Comparative assessment of electronic nicotine delivery systems aerosol and cigarette smoke on endothelial cell migration: The Replica Project

Cigarette smoking is associated with impairment of repair mechanisms necessary for vascular endothelium homeostasis. Reducing the exposure to smoke toxicants may result in the mitigation of the harmful effect on the endothelium and cardiovascular disease development. Previous investigations evaluated in vitro the effect of electronic cigarette (EC) compared with cigarette smoke demonstrating a significant reduction in human umbilical vein endothelial cells (HUVECs) migration inhibition following EC aerosol exposure. In the present study, we replicated one of these studies, evaluating the effects of cigarette smoke on endothelial cell migration compared with aerosol from EC and heated tobacco products (HTPs). We performed an in vitro scratch wound assay on endothelial cells with a multi-center approach (ring-study) to verify the robustness and reliability of the results obtained in the replicated study, also testing the effect of aerosol from two HTPs on endothelial cells. Consistently with the original study, we observed a substantial reduction of the effects of aerosol from EC and HTPs on endothelial cell migration compared with cigarette smoke. While cigarette smoke reduced endothelial wound healing ability already at low concentrations (12.5%) and in a concentration-dependent manner, EC and HTPs aerosol showed no effect on endothelial cells until 80%-100% concentrations. In conclusion, our study further confirms the importance of EC and tobacco heated products as a possible harm reduction strategy for cardiovascular diseases development in smokers.

Exposure keratopathy and its associated risk factors in patients undergoing general anesthesia in nonocular surgeries

INTRODUCTION

The most common eye injury during and after general anesthesia is corneal abrasion which can occur at any time after anesthesia and even up to 24 h after it. The aim of this study was to investigate the incidence and factors associated with corneal injury in patients undergoing nonocular surgery.

METHODS

This was a descriptive cross-sectional study. A total of 170 patients, who were admitted to the operating room and met the inclusion criteria, were selected through simple nonprobability sampling. Data collection forms were used in order to assess the incidence of corneal injury and its related risk factors. The National Eye Institute scale with fluorescein paper and cobalt blue light by slit lamp were utilized to examine exposure keratopathy.

RESULTS

Overall, the results showed that the incidence of keratopathy immediately after eye care removal was found to be 64.7% in the operating room, 65.9% in the recovery room, and 41.2% in 24 h after the surgery. Smokers' patients and drug abusers under general anesthesia underwent endotracheal intubation, received more opioids preoperatively, and had more perioperative bleeding and fluid intake. Moreover, in patients who had received more oxygen flow in the recovery room; the rate of keratopathy was higher.

CONCLUSION

Smoking, drug usage, and receiving endotracheal intubation are the risk factors of keratopathy. Therefore, for high-risk patients and procedures, it is indispensable to both obtain preoperative information and take intraoperative precautions in order to prevent eye injuries. Future studies are needed to demonstrate these finding.

Zeb1 promotes corneal neovascularization by regulation of vascular endothelial cell proliferation

Angiogenesis is required for tissue repair; but abnormal angiogenesis or neovascularization (NV) causes diseases in the eye. The avascular status in the cornea is a prerequisite for corneal clarity and thought to be maintained by the equilibrium between proangiogenic and antiangiogenic factors that controls proliferation and migration of vascular endothelial cells (ECs) sprouting from the pericorneal plexus. VEGF is the most important intrinsic factor for angiogenesis; anti-VEGF therapies are available for treating ocular NV. However, the effectiveness of the therapies is limited because of VEGF-independent mechanism(s). We show that Zeb1 is an important factor promoting vascular EC proliferation and corneal NV; and a couple of small molecule inhibitors can evict Ctbp from the Zeb1-Ctbp complex, thereby reducing EC Zeb1 expression, proliferation, and corneal NV. We conclude that Zeb1-regulation of angiogenesis is independent of Vegf and that the ZEB1-CtBP inhibitors can be of potential therapeutic significance in treating corneal NV.

A Systematic Review on Classification, Identification, and Healing Process of Burn Wound Healing

Because of the intrinsic complexity, the classification of wounds is important for the diagnosis, management, and choosing the correct treatment based on wound type. Generally, burn injuries are classified as a class of wounds in which injury is caused by heat, cold, electricity, chemicals, friction, or radiation. On the other hand, wound healing is a complex process, and understanding the biological trend of this process and differences in the healing process of different wounds could reduce the possible risk in many cases and greatly reduce the future damage to the injured tissue and other organs. The aim of this review is to provide a general perspective for the burn wound location among the other types of injuries and summarizing as well as highlighting the differences of these types of wounds with emphasizing on factors affecting thereof.

Comparative Analysis of KGF-2 and bFGF in Prevention of Excessive Wound Healing and Scar Formation in a Corneal Alkali Burn Model

PURPOSE

Basic fibroblast growth factor (bFGF) is an effective drug for corneal injury. However, the explicit role of bFGF in corneal scar formation still remains unclear. Keratinocyte growth factor-2 (KGF-2) is associated with the treatment of wound healing. We aimed to compare the efficacy of bFGF and KGF-2 in prevention of excessive wound healing and consequent scar formation in a rat alkali burn model, which provides important clues on the significance of KGF-2 to be developed as a new drug for such injuries.

METHODS

The epithelial defect area was evaluated using fluorescein sodium at a concentration of 0.5%. The therapeutic effect of KGF-2 and bFGF on proliferation of rabbit corneal fibroblasts (RCFs) was evaluated by methylthiazoletetrazolium. RCF migration assays were performed with a modified scratch method. Activation of mitogen-activated protein kinase (MAPK) was evaluated by Western blot with specific antibodies.

RESULTS

All corneal wounds treated with KGF-2 were found closed within 7 days; however, the wounds treated with bFGF or phosphate buffer saline (PBS) required 14 days to close. RCFs treated with KGF-2 or bFGF showed similar dose-dependent proliferation. The KGF-2 group significantly promoted cell migration compared with the bFGF group. The KGF-2 group showed less expression of α-smooth muscle actin (SMA) and numbers of myofibroblasts compared with the bFGF group. Our findings suggested identification of cascade reaction of extracellular regulated protein kinases (ERK)1/2 and p38 signals in KGF-2- and bFGF-induced proliferation and migration of RCFs. In addition, KGF-2 showed stronger effects during ERK1/2 and p38 phosphorylation in methylthiazoletetrazolium proliferation assay and scratch migration assay.

CONCLUSIONS

KGF-2 exhibited better effects than bFGF in reepithelialization, acceleration of migration, and reduction of scar formation, which has potential to become a new drug to cure corneal injury.

Nicotine increased VEGF and MMP2 levels in the rat eye and kidney

Chronic cigarette smoking affects many tissues negatively. Nicotine in tobacco has negative effects on tissues, kidneys, and eyes especially, where microcirculation is vitally important for the survival and functioning. It is known that appropriate vascular endothelial growth factor (VEGF) and (matrix metalloproteinase 2) MMP2 levels are required for suitable vascularity and enough microcirculation. The aim of this study was to investigate the effect of nicotine on VEGF and MMP2 levels in kidney and eyes, where microcirculation is very important for their function. The nicotine was given into drinking water, to male and female rats for 6 weeks. During the first 2 weeks, the nicotine concentration was 10 mg/L, then was given at a fixed dose of 20 mg/L until the end of the experiment. The VEGF and MMP2 levels were increased in kidney tissue of both genders as a result of given nicotine. MMP2 levels were also increased in the eye tissue for both genders similarly. However, VEGF levels increased in the eye tissue with nicotine in males, whereas it did not change in females. The use of nicotine made VEGF and MMP2 levels increase in kidney tissue in both genders of rats. This increase in VEGF was observed only in male eye tissue, not in females. According to our findings, it can be suggested that nicotine has negative effects on microvascular circulation by increasing VEGF and MMP2 levels. In addition, it should be pointed out that estrogen might have protective effects on female eye tissue. Further studies are necessary to understand the complex relationship between the role of nicotine and estrogen on eye and kidney tissues.

Continuous exposure of nicotine and cotinine retards human primary pterygium cell proliferation and migration

Pterygium is a triangular-shaped hyperplastic growth, characterized by conjunctivalization, inflammation, and connective tissue remodeling. Our previous meta-analysis found that cigarette smoking is associated with a reduced risk of pterygium. Yet, the biological effect of cigarette smoke components on pterygium has not been studied. Here we reported the proliferation and migration properties of human primary pterygium cells with continuous exposure to nicotine and cotinine. Human primary pterygium cells predominantly expressed the α5, β1, and γ subunits of the nicotinic acetylcholine receptor. Continuous exposure to the mixture of 0.15 μM nicotine and 2 μM cotinine retarded pterygium cell proliferation by 16.04% (P = 0.009) and hindered their migration by 11.93% ( P = 0.039), without affecting cell apoptosis. SNAIL and α-smooth muscle actin protein expression was significantly downregulated in pterygium cells treated with 0.15 μM nicotine-2 μM cotinine mixture by 1.33- ( P = 0.036) and 1.31-fold ( P = 0.001), respectively. Besides, the 0.15 μM nicotine-2 μM cotinine mixture also reduced matrix metalloproteinase (MMP)-1 and MMP-9 expressions in pterygium cells by 1.56- ( P = 0.043) and 1.27-fold ( P = 0.012), respectively. In summary, this study revealed that continuous exposure of nicotine and cotinine inhibited human primary pterygium cell proliferation and migration in vitro by reducing epithelial-to-mesenchymal transition and MMP protein expression, partially explaining the lower incidence of pterygium in cigarette smokers.