5-Fluorouracil-Induced Apoptosis Changes in Cultured Corneal Epithelial Cells

5-Flourouracil-induced toxicity in both male and female reproductive systems: A narrative review

The chemotherapeutic drug 5-flourouracil (5FU) is frequently used to treat a wide range of solid malignant tumors, such as colorectal, pancreatic, gastric, breast, and head and neck cancers. Its antitumoral effects are achieved by interfering with the synthesis of RNA and DNA and by inhibiting thymidylate synthase in both malignant and non-malignant cells. Therefore, it can be responsible for severe toxicities in crucial body organs, including heart, liver, kidney, and reproductive system. Given the fact that 5FU-induced reproductive toxicity may limit the clinical application of this drug, in this study, we aimed to discuss the main locations and mechanisms of the 5FU-induced reproductive toxicity. Initially, we discussed the impact of 5FU on the male reproductive system, which leads to damage of the seminiferous epithelial cells and the development of vacuoles in Sertoli cells. Although no noticeable changes occur at the histopathological level, there is a decrease in the weight of the prostate. Additionally, 5FU causes significant abnormalities in spermatogenesis, including germ cell shedding, spermatid halo formation, polynucleated giant cells, and decreased sperm count. Finally, in females, 5FU-induced reproductive toxicity is characterized by the presence of atretic secondary and antral follicles with reduced numbers of growing follicles, ovarian weight, and maturity impairment.

5-Fluorouracil in primary, impending recurrent and recurrent pterygium: Systematic review of the efficacy and safety of a surgical adjuvant and intralesional antimetabolite

Pterygium is an ultraviolet-related disease characterized by an aberrant, wing-shaped and active wound-healing process. There is nothing quite as disheartening for the surgeon or patient as the recurrence of pterygium, and various adjuvants have been studied to ameliorate this. This systematic review provides a comprehensive summary of the efficacy and safety of 5-Fluorouracil (5-FU) as an antimetabolite agent for pterygium management. An appraisal of electronic searches of six databases identified 34 clinical studies reporting recurrence outcomes of 5-FU use in primary, impending recurrent and recurrent pterygia. In vitro and in vivo studies of 5-FU showed dose- and duration-dependent cytostatic and cytotoxic effects in human cells. 5-FU is relatively inexpensive, available, and easy to administer, making it attractive for resource-limited scenarios. However, the published evidence demonstrates a recurrence rate of 11.4-60% with the bare scleral technique, 3.5-35.8% with conjunctival rotational flaps, 3.7-9.6% with conjunctival autografts for intraoperative topical 5-FU, and 14-35.8% for preoperative and intraoperative injections. This suboptimal efficacy brings the role of 5-FU as an adjuvant for pterygium surgery into question and the authors do not recommend its use. In contrast, postoperative intralesional injections of 5-FU to arrest progression in impending recurrent pterygium and true recurrent pterygia were more promising, with success rates of 87.2-100% and 75-100%, respectively. Furthermore, 5-FU as a treatment modality, without surgery, effectively arrested progression in 81.3-96% of primary and recurrent pterygia. Other treatments such as topical and intralesional corticosteroids, cyclosporine and anti-VEGF agents are discussed. Complications of 5-FU increase with higher doses and range from transient and reversible to severe and sight-threatening. For pterygium, 5-FU has a predilection for causing scleral thinning, corneal toxicity, and graft-related complications. Additional study with extended follow-up is needed to elucidate the optimal dose, frequency, duration, and long-term safety of 5-FU injections. If 5-FU is used in the management of pterygium, it should be with caution, in selected patients and with vigilant long-term monitoring.

Ten Years of Knowledge of Nano-Carrier Based Drug Delivery Systems in Ophthalmology: Current Evidence, Challenges, and Future Prospective

The complex drug delivery barrier in the eye reduces the bioavailability of many drugs, resulting in poor therapeutic effects. It is necessary to investigate new drugs through appropriate delivery routes and vehicles. Nanotechnology has utilized various nano-carriers to develop potential ocular drug delivery techniques that interact with the ocular mucosa, prolong the retention time of drugs in the eye, and increase permeability. Additionally, nano-carriers such as liposomes, nanoparticles, nano-suspensions, nano-micelles, and nano-emulsions have grown in popularity as an effective theranostic application to combat different microbial superbugs. In this review, we summarize the nano-carrier based drug delivery system developments over the last decade, particularly review the biology, methodology, approaches, and clinical applications of nano-carrier based drug delivery system in the field of ocular therapeutics. Furthermore, this review addresses upcoming challenges, and provides an outlook on potential future trends of nano-carrier-based drug delivery approaches in ophthalmology, and hopes to eventually provide successful applications for treating ocular diseases.

Effect of multiple subconjunctival conbercept injections as an adjuvant to the surgical treatment of pterygium: a prospective randomised comparative 6-month follow-up study

OBJECTIVE

To evaluate the safety and efficacy of multiple subconjunctival injections of conbercept for pterygium patients after surgery.

METHODS

As a prospective randomised interventional trial, 96 eyes from 96 patients with a tendency to recur were collected and divided randomly into conbercept and 5-fluorouracil groups on the 5th day after pterygium. All patients received three subconjunctival injections of conbercept (0.2 ml) or 5-fluorouracil (0.2 ml) on the 5th day (baseline), and 2 and 4 weeks post-operatively. The pterygium morphology, colour intensity, recurrence, and complications were recorded and analysed pre-1st injection and 1 day, 1 week, 1 month, 3 months, and 6 months post-3rd injection. Moreover, no patient was drop-out.

RESULTS

There were striking differences between the two groups on post-3rd injections 1 day, 1 week, 1 month, 3 months, and 6 months (p = 0.001, 0.002, 0.000, 0.000, and 0.002, respectively) with respect to colour intensity: the eyes in conbercept group were lighter than the 5-Fu group. On post-3rd injection 6 months, prominent disparities existed between the two groups with respect to pterygium morphology (p = 0.006) and recurrence (p = 0.002), occurred in the conbercept group prior to the 5-Fu group. Moreover, corneal abrasions were not noted in the conbercept group, which was significantly less than the 5-Fu group (17/48; p = 0.000). There was no conspicuous discrepancy between the two groups with respect to subconjunctival haemorrhage (p = 0.789) and persistent epithelial defects (p = 0.078).

CONCLUSION

Multiple subconjunctival conbercept injections as an adjunct therapy for pterygium surgery was shown to be safe, effective, and well-tolerated.

Effect of subconjunctival injection with conbercept as an adjuvant to filtration surgery for open angle glaucoma: a prospective randomized interventional 6-month follow-up study

AIM

To compare the safety and efficacy of subconjunctival injection with conbercept and 5-fluorouracil (5-FU) for open angle glaucoma (OAG) patients after filtration surgery.

METHODS

As a prospective randomized interventional trial, 36 eyes from 36 patients after OAG surgery were collected and divided randomly into conbercept and 5-FU groups. All patients were subconjunctivally injected with either conbercept (0.2 mL) or 5-FU (0.2 mL) on the 5^th day post-operatively. The intraocular pressure (IOP), number of medications used, type of conjunctival bleb, and complications were recorded and analyzed pre-operatively and 1d, 1wk, 1, 3 and 6mo post-injection.

RESULTS

There were significant differences in IOP between the conbercept and 5-FU groups 1mo (conbercept group: 12.17±1.04 mm Hg; 5-FU group: 13.50±2.33 mm Hg, t=2.214, P=0.037), 3mo (conbercept group: 13.00±1.88 mm Hg; 5-FU group: 14.50±2.28 mm Hg, t=2.153, P=0.039), and 6mo post-injection (conbercept group: 13.28±2.95 mm Hg; 5-FU group: 15.22±2.49 mm Hg, t=2.140, P=0.040); however, in the number of medications, a prominent difference was not shown between groups on post-injection 6mo (t=1.312, P=0.200). Moreover, there was mild vascularity observed in the conbecept group than the 5-FU group 1d (3a, 3b, 3c: t=8.497, 6.693, 4.515, P=0.000), 1wk (3a, 3b, 3c: t=3.431, 6.408, 3.984, P=0.002, 0.000, 0.000), and 1mo post-injection (3a, 3b, 3c: t=2.466, 2.466, 2.503, P=0.019, 0.019, 0.017). Simultaneously, differences from other indicators between the two groups were not demonstrated. Also, there was a lower probability of corneal epithelial stripping in the conbercept group than the 5-FU group (χ ²=4.500, P=0.034).

CONCLUSION

Subconjunctival injection of conbercept has a safe, effective, and tolerable profile for open angle glaucoma patients with distinct conjunctival congestion after filtration surgery.

Metformin inhibited colitis and colitis-associated cancer (CAC) through protecting mitochondrial structures of colorectal epithelial cells in mice

Although a mountain of papers have showed that metformin plays a role in inhibiting cancers, but the mechanism underpinning this has not yet fully elucidated. Herein, we used AOM/DSS model, the clinicopathological features are similar to those found in humans, to investigate the effects of metformin as well as combination with 5-FU in the prevention of colitis and colitis associated cancer (CAC). Oral metformin significantly inhibited DSS-induced ulcerative colitis and AOM/DSS-induced CAC. Metformin also ameliorated 5-FU-induced colorectal gastrointestinal symptoms in mice. Metformin combination with 5-FU strongly inhibited colorectal cancer. Metformin reduced levels of the NFκB signaling components p-IKKα/β, p-NFκB, p-IκBα in colorectal mucosal cells. Transmission electron microscopy analysis suggested that the inhibition of metformin on colitis and CAC might associate with its biological activity of protecting mitochondrial structures of colorectal epithelial cells. Further analysis by Mito Tracker Red staining assay indicated that metformin prevented H₂O₂-induced mitochondrial fission correlated with a decrease of mitochondrial perimeter. In addition, metformin increased the level of NDUFA9, a Q-module subunit required for complex I assembly, in colorectal epithelial cells. These observations of metformin in the inhibition of colitis and CAC might associate with its activity of activating the LKB1/AMPK pathway in colorectal epithelial cells. In conclusion, metformin inhibited colitis and CAC through protecting the mitochondrial structures of colorectal epithelial cells.

Conditional reprogrammed human limbal epithelial cells represent a novel in vitro cell model for drug responses

In this study, we established human limbal epithelial cells (LECs) from normal limbal tissues by using Conditional Reprogramming (CR) technology (refer to CR-LEC cells in this study). We have successfully established CR-LEC cell strains from three human donors (3 out of 3), and normal rabbits (2 out of 2) and pig (1 out of 1) as well. CR-LEC cells sustained a continuous and stable proliferation status with a normal karyotype, normal response to DNA damage, well-defined structured spheres in matrigel 3D culture. Responses of CR-LEC cells to IFN α2b, Ganciclovir and 5-Fluorouracil were different, suggesting that these drugs had different toxicities to these cells as expected. More important, there was no significant difference of responses to drugs between early and late passages of CR-LEC cells (p>0.05), indicating CR-LEC cells can serve a stable normal human cell model for toxicity assessment. Toxicity tests with monolayer cultures of CR-LEC cells were measured by staining the F-actin and Dsg-1 expression. Toxicity of three drugs at LD50 concentration resulted in a gradually increased destruction of monolayer, which is, in accordance with the irritation grade of three drugs on human cornea epithelium. Therefore, CR-LEC cells provide a novel and reliable in vitro physiological cell model for corneal toxicity assessment.

Development and validation of an LC-MS/MS quantitative method for endogenous deoxynucleoside triphosphates in cellular lysate

The endogenous deoxynucleoside triphosphate (dNTP) pool includes deoxyadenosine triphosphate (dATP), deoxycytidine triphosphate (dCTP), deoxyguanosine triphosphate (dGTP) and thymidine triphosphate (TTP). The endogenous dNTP pool is regulated by complex enzymatic pathways that can be targeted by drugs, such as antimetabolites. In addition, these components compete with antiviral nucleos(t)ide analog triphosphates, contributing to the mechanism of pharmacologic action. This communication describes the development and validation of a sensitive method to quantify the intracellular dNTP pool in cellular lysates. The extraction process was optimized for dNTPs using an indirect strategy - the separation of mono-, di- and triphosphate moieties by strong anion exchange, dephosphorylation of target fractions to molar equivalent nucleosides - followed by sensitive quantitation using liquid chromatography-tandem mass spectrometry. The validated analytical range was 50-2500 fmol/sample for each dNTP. The assay was used to quantify dNTPs in peripheral blood mononuclear cells from 40 clinical research participants (n = 279 samples). Median (interquartile range) concentrations were 143 (116, 169) for dATP, 737 (605, 887) for dCTP, 237 (200, 290) for dGTP and 315 (220, 456) for TTP, in femtomoles per million cells. This method allows for future studies of endogenous dNTP disposition in subjects receiving antimetabolites or nucleos(t)ide analogs, or for other clinical scenarios.