Effects of HGF and KGF gene silencing on vascular endothelial growth factor and its receptors in rat ultraviolet radiation‑induced corneal neovascularization

Elucidating the mechanism of corneal epithelial cell repair: unraveling the impact of growth factors

The repair mechanism for corneal epithelial cell injuries encompasses migration, proliferation, and differentiation of corneal epithelial cells, and extracellular matrix remodeling of the stromal structural integrity. Furthermore, it involves the consequential impact of corneal limbal stem cells (LSCs). In recent years, as our comprehension of the mediating mechanisms underlying corneal epithelial injury repair has advanced, it has become increasingly apparent that growth factors play a pivotal role in this intricate process. These growth factors actively contribute to the restoration of corneal epithelial injuries by orchestrating responses and facilitating specific interactions at targeted sites. This article systematically summarizes the role of growth factors in corneal epithelial cell injury repair by searching relevant literature in recent years, and explores the limitations of current literature search, providing a certain scientific basis for subsequent basic research and clinical applications.

Modulating Growth Factor Receptor Signaling to Promote Corneal Epithelial Homeostasis

The corneal epithelium is the first anatomical barrier between the environment and the cornea; it is critical for proper light refraction onto the retina and prevents pathogens (e.g., bacteria, viruses) from entering the immune-privileged eye. Trauma to the highly innervated corneal epithelium is extremely painful and if not resolved quickly or properly, can lead to infection and ultimately blindness. The healthy eye produces its own growth factors and is continuously bathed in tear fluid that contains these proteins and other nutrients to maintain the rapid turnover and homeostasis of the ocular surface. In this article, we review the roles of growth factors in corneal epithelial homeostasis and regeneration and some of the limitations to their use therapeutically.

Radioprotection of deinococcal exopolysaccharide BRD125 by regenerating hematopoietic stem cells

There is a substantial need for the development of biomaterials for protecting hematopoietic stem cells and enhancing hematopoiesis after radiation damage. Bacterial exopolysaccharide (EPS) has been shown to be very attractive to researchers as a radioprotectant owing to its high antioxidant, anti-cancer, and limited adverse effects. In the present study, we isolated EPS from a novel strain, Deinococcus radiodurans BRD125, which produces EPS in high abundance, and investigated its applicability as a radioprotective biomaterial. We found that EPS isolated from EPS-rich D. radiodurans BRD125 (DeinoPol-BRD125) had an excellent free-radical scavenging effect and reduced irradiation-induced apoptosis. In addition, bone-marrow and spleen-cell apoptosis in irradiated mice were significantly reduced by DeinoPol-BRD125 administration. DeinoPol-BRD125 enhanced the expression of hematopoiesis-related cytokines such as GM-CSF, G-GSF, M-CSF, and SCF, thereby enhancing hematopoietic stem cells protection and regeneration. Taken together, our findings are the first to report the immunological mechanism of a novel radioprotectant, DeinoPol-BRD125, which might constitute an ideal radioprotective and radiation mitigating agent as a supplement drug during radiotherapy.

Plasma Levels of Keratinocyte Growth Factor Are Significantly Elevated for 5 Weeks After Minimally Invasive Colorectal Resection Which May Promote Cancer Recurrence and Metastasis

Background: Human Keratinocyte Growth Factor (KGF) is an FGF family protein produced by mesenchymal cells. KGF promotes epithelial cell proliferation, plays a role in wound healing and may also support tumor growth. It is expressed by some colorectal cancers (CRC). Surgery's impact on KGF levels is unknown. This study's purpose was to assess plasma KGF levels before and after minimally invasive colorectal resection (MICR) for CRC. Aim: To determine plasma KGF levels before and after minimally invasive colorectal resection surgery for cancer pathology. Method: CRC MICR patients (pts) in an IRB approved data/plasma bank were studied. Pre-operative (pre-op) and post-operative (post-op) plasma samples were taken/stored. Late samples were bundled into 7 day blocks and considered as single time points. KGF levels (pg/ml) were measured via ELISA (mean ± SD). The Wilcoxon paired t-test was used for statistical analysis. Results: Eighty MICR CRC patients (colon 61%; rectal 39%; mean age 65.8 ± 13.3) were studied. The mean incision length was 8.37 ± 3.9 and mean LOS 6.5 ± 2.6 days. The cancer stage breakdown was; I (23), II (26), III (27), and IV (4). The median pre-op KGF level was 17.1 (95 %CI: 14.6-19.4; n = 80); significantly elevated (p < 0.05) median levels (pg/ml) were noted on post-op day (POD) 1 (23.4 pg/ml; 95% CI: 21.4-25.9; n = 80), POD 3 (22.5 pg/ml; 95% CI: 20.7-25.9; n = 76), POD 7-13 (21.8 pg/ml; 95% CI: 17.7-25.4; n = 50), POD 14-20 (20.1 pg/ml; 95% CI: 17.1-23.9; n = 33), POD 21-27 (19.6 pg/ml; 95% CI: 15.2-24.9; n = 15) and on POD 28-34 (16.7 pg/ml; 95% CI: 14.0-25.8; n = 12). Conclusion: Plasma KGF levels were significantly elevated for 5 weeks after MICR for CRC. The etiology of these changes is unclear, surgical trauma related acute inflammatory response and wound healing process may play a role. These changes, may stimulate angiogenesis in residual tumor deposits after surgery.

Wound healing of the corneal epithelium: a review

The corneal epithelium (CE) forms the outermost layer of the cornea. Despite its thickness of only 50 μm, the CE plays a key role as an initial barrier against any insults to the eye and contributes to the light refraction onto the retina required for clear vision. In the event of an injury, the cornea is equipped with many strategies contributing to competent wound healing, including angiogenic and immune privileges, and mechanotransduction. Various factors, including growth factors, keratin, cytokines, integrins, crystallins, basement membrane, and gap junction proteins are involved in CE wound healing and serve as markers in the healing process. Studies of CE wound healing are advancing rapidly in tandem with the rise of corneal bioengineering, which employs limbal epithelial stem cells as the primary source of cells utilizing various types of biomaterials as substrates.

Self-Retained Cryopreserved Amniotic Membrane for the Management of Corneal Ulcers

Purpose

To evaluate the clinical outcomes of self-retained cryopreserved amniotic membrane (cAM) for the treatment of corneal ulcers.

Methods

This was a single-center, retrospective review of consecutive patients with non-healing corneal ulcers that underwent treatment with self-retained cAM (PROKERA^® Slim). The primary outcome measure was time to complete corneal epithelialization. Ocular discomfort, corneal staining, corneal signs, and visual acuity were assessed at 1 week, 1 month, 3 months, and 6 months. Complications, adverse events, and ulcer recurrence were also recorded.

Results

A total of 13 eyes (13 patients) with recalcitrant corneal ulcers were included for analysis, 9 (69%) of which progressed from neurotrophic keratitis (NK). Prior to cAM application, patients used conventional treatments such as artificial tears (n = 11), antibiotics (n = 11), ointment (n = 11), steroids (n = 6), and antivirals (n = 3). Self-retained cAMs (n = 1.5 ± 0.8) were placed for 6.8 ± 3.4 days, during which time antibiotics were continued. Four cases (31%) were subsequently treated with bandage contact lens (n = 3) and tarsorrhaphy (n = 1). All corneal ulcers healed in a median of 14 days (range: 4-43). This was accompanied by a significant improvement in ocular discomfort, corneal staining, and corneal signs at 1 week, 1 month, 3 months, and 6 months (P<.05). Recurrence was noted in one case. No adverse events were observed.

Conclusion

Self-retained cAM may be a valuable, in-office treatment option for healing recalcitrant corneal ulcers of various etiologies, especially those with underlying NK. Further prospective, controlled studies are warranted.

Amniotic membrane transplantation for managing dry eye and neurotrophic keratitis

Neurotrophic keratitis (NK), a degenerative disease caused by damage to the trigeminal nerve, abolishes both tearing and blinking reflexes, thus causing the most severe forms of dry eye disease (DED). Conversely, the increasing severity of DED also leads to progressive loss of corneal nerve density, potentially resulting in NK. Both diseases manifest the same spectrum of corneal pathologies including inflammation and corneal epithelial keratitis, which can progress into vision-threatening epithelial defect and stromal ulceration. This review summarizes the current literature regarding outcomes following sutured and sutureless cryopreserved amniotic membrane (AM) in treating DED as well as epithelial defects and corneal ulcers due to underlying NK. These studies collectively support the safety and effectiveness of cryopreserved AM in restoring corneal epithelial health, improving visual acuity in eyes with NK and DED, and alleviating symptomatic DED. Future randomized controlled trials are warranted to validate the above findings and determine whether such clinical efficacy lies in promoting corneal nerve regeneration.