Efficacy of granulocyte-colony stimulating factor treatment in a rat model of anterior ischemic optic neuropathy

Nanoparticles for the treatment of glaucoma-associated neuroinflammation

Recently, a considerable amount of literature has emerged around the theme of neuroinflammation linked to neurodegeneration. Glaucoma is a neurodegenerative disease characterized by visual impairment. Understanding the complex neuroinflammatory processes underlying retinal ganglion cell loss has the potential to improve conventional therapeutic approaches in glaucoma. Due to the presence of multiple barriers that a systemically administered drug has to cross to reach the intraocular space, ocular drug delivery has always been a challenge. Nowadays, studies are focused on improving the current therapies for glaucoma by utilizing nanoparticles as the modes of drug transport across the ocular anatomical and physiological barriers. This review offers some important insights on the therapeutic advancements made in this direction, focusing on the use of nanoparticles loaded with anti-inflammatory and neuroprotective agents in the treatment of glaucoma. The prospect of these novel therapies is discussed in relation to the current therapies to alleviate inflammation in glaucoma, which are being reviewed as well, along with the detailed molecular and cellular mechanisms governing the onset and the progression of the disease.

Intravitreal Injection of Long-Acting Pegylated Granulocyte Colony-Stimulating Factor Provides Neuroprotective Effects via Antioxidant Response in a Rat Model of Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) may cause severe visual loss following direct or indirect head trauma which may result in optic nerve injuries and therefore contribute to the subsequent loss of retinal ganglion cells by inflammatory mediators and reactive oxygen species (ROS). Granulocyte colony-stimulating factor (G-CSF) provides the anti-inflammatory and anti-oxidative actions but has a short half-life and also induces leukocytosis upon typical systemic administration. The purpose of the present study was to investigate the relationship between the anti-oxidative response and neuroprotective effects of long-acting pegylated human G-CSF (PEG-G-CSF) in a rat model of optic nerve crush (ONC). Adult male Wistar rats (150-180 g) were chosen to have a sham operation in one eye and have ONC in the other. PEG-G-CSF or phosphate-buffered saline (PBS control) was immediately administered after ONC by intravitreal injection (IVI). We found the IVI of PEG-G-CSF does not induce systemic leukocytosis, but increases survival of RGCs and preserves the visual function after ONC. TUNEL assays showed fewer apoptotic cells in the retina in the PEG-G-CSF-treated eyes. The number of sorely ED1-positive cells was attenuated at the lesion site in the PEG-G-CSF-treated eyes. Immunoblotting showed up-regulation of p-Akt1, Nrf2, Sirt3, and HO-1 in the ON of the PEG-G-CSF-treated eyes. Our results demonstrated that one IVI of long-acting PEG-G-CSF is neuroprotective in the rONC. PEG-G-CSF activates the p-Akt1/Nrf2/Sirt3 and the p-Akt1/Nrf2/HO-1 axes to provide the antioxidative action and further attenuated RGC apoptosis and neuroinflammation. This provides crucial preclinical information for the development of alternative therapy with IVI of PEG-G-CSF in TON.

Intravitreal Injection Of The Granulocyte-Colony Stimulating Factor For The Treatment Of Non-Arteritic Anterior Ischemic Optic Neuropathy: A Pilot Study

Purpose To investigate the efficacy of intravitreal injection of granulocyte colony-stimulating factor (G-CSF) for the treatment of non-arteritic anterior ischemic optic neuropathy (NAION).Methods: Patients with acute NAION were enrolled in this prospective interventional case series. They received an intravitreal injection of 60 micrograms in 0.1 ml of G-CSF within 2 weeks of the onset of the disease. Visual acuity, visual field, intraocular pressure (IOP), corneal endothelial cell density, and peripapillary retinal nerve fiber layer (RNFL) thickness were recorded before injections and 1 week, 1 month, 3 months, 6 months, and one year after the injections. Full-field electroretinography (ERG) was obtained at the baseline, 1 month, and 12 months post- injections.Results: Fourteen eyes of 14 patients entered the study. Best-corrected visual acuity (BCVA) significantly improved in the first month following injections (p = .007), decreased subsequently, and the final BCVA showed no significant improvement (p = .278) compared to the baseline measurements. A significant decrease in RNFL thickness was observed in all quadrants compared to the baseline measurements. Also, no improvement in the visual field parameters was observed. From the toxicity aspect, no significant changes in the corneal endothelial cell density, IOP, and ERG recordings were observed.Conclusion: Intravitreal injection of G-CSF seems to be safe. The effect may last for one month and then decline.

A rodent model of anterior ischemic optic neuropathy (AION) based on laser photoactivation of verteporfin

Background

A rodent model of photodynamic AION resulting from intravenous verteporfin is presented. The analysis of the morphological function, the pathological changes and the potential mechanism of action were further investigated.

Methods

Photodynamic treatment was conducted on the optic nerve head (ONH) following administration of the photosensitizer. The fellow eye was considered as sham control. Fundus Fluorescein angiography (FFA), spectral domain optical coherence tomography (SD-OCT) and Flash-visual evoked potential (F-VEP) recordings were conducted at different time points. Immunohistochemistry was used to observe apoptotic cell death (TUNEL) and macrophage infiltration (ED-1/Iba-1). Retrograde labeling of retinal ganglion cells (RGCs) was used to evaluate the loss of RGCs.

Results

After laser treatment, SD-OCT indicated optic nerve edema, while FFA indicated late leakage of the ONH. F-VEPs were distinctly reduced compared to control eyes. The number of apoptotic RGCs peaked on day 14 (5.71 ± 0.76, p < 0.01). The infiltration of ED-1 and Iba-1 increased on the 3rd day following PDT, while it peaked on day 14 (67.5 ± 9.57 and 77.5 ± 12.58 respectively, p < 0.01). Following 3 weeks of AION, the densities of RGCs in the central retinas of the normal and AION eyes were 3075 ± 298/mm² and 2078 ± 141/mm² (p < 0.01), respectively.

Conclusions

Verteporfin photodynamic treatment on rodents ONH can lead to functional, histological, and pathological changes. This type of animal model of AION is easy to establish and stable. It can be used for studying the mechanism and neuroprotective medicine of AION injury.

Generation and characterization of transgenic mouse mesenchymal stem cell lines expressing hIGF-1 or hG-CSF

Mesenchymal stem cells (MSC) are promising tools in the fields of cell therapy and regenerative medicine. In addition to their differentiation potential, MSC have the ability to secrete bioactive molecules that stimulate tissue regeneration. Thus, the overexpression of cytokines and growth factors may enhance the therapeutic effects of MSC. Here we generated and characterized mouse bone marrow MSC lines overexpressing hG-CSF or hIGF-1. MSC lines overexpressing hG-CSF or hIGF-1 were generated through lentiviral vector mediated gene transfer. The expression of hG-CSF or hIGF-1 genes in the clones produced was quantified by qRT-PCR, and the proteins were detected in the cell supernatants by ELISA. The cell lines displayed cell surface markers and differentiation potential into adipocytes, osteocytes and chondrocytes similar to the control MSC cell lines, indicating the conservation of their phenotype even after genetic modification. IGF-1 and G-CSF transgenic cells maintained immunosuppressive activity. Finally, we performed a comparative gene expression analysis by qRT-PCR array in the cell lines expressing hIGF-1 and hG-CSF when compared to the control cells. Our results demonstrate that the cell lines generated may be useful tools for cell therapy and are suitable for testing in disease models.

Expression of granulocyte colony-stimulating factor 3 receptor in the spinal dorsal horn following spinal nerve ligation-induced neuropathic pain

In previous studies that have profiled gene expression in patients with complex regional pain syndrome (CRPS), the expression of granulocyte colony-stimulating factor 3 receptor (G-CSFR) was elevated, as were a number of pain-associated genes. The present study determined the expression of G-CSFR and the mechanisms by which it may affect hypersensitivity, focusing on the signal transducer and activator of transcription 3 (STAT3)/transient receptor potential cation channel subfamily V 1 (TRPV1) signaling pathway in particular, which is an important mediator of pain. Following L5 spinal nerve ligation (SNL) surgery, the protein and mRNA levels of G-CSFR increased in the ipsilateral spinal dorsal horn when compared with the sham and/or contralateral control. Double immunofluorescence further demonstrated that G-CSFR colocalized with TRPV1 and phosphorylated STAT in the neurons of the spinal dorsal horn. G-CSF treatment led to an increase in G-CSFR and TRPV1 expression and phosphorylation of STAT3. These results indicate that G-CSF-induced G-CSFR expression may activate TRPV1 by promoting phosphorylation of STAT3. Collectively, the results suggest, for the first time, that the expression of G-CSFR in neurons following peripheral nerve injury may be involved in the induction and maintenance of neuropathic pain through the STAT3 and TRPV1 signaling pathway.

Alterations in the expression of Hs1-associated protein X-1 in the rat retina after optic nerve crush

HS-1-associated protein X-1 (Hax-1) has been suggested to be expressed in various rodent and human tissues. Accumulating evidence has demonstrated that Hax‑1 exerts an anti‑apoptotic effect in neurological diseases. Furthermore, it has also been reported that Hax‑1 interacts with various apoptosis‑associated proteins, including high temperature-regulated A2 (HtrA2) and caspase‑3. Previous studies have indicated that abnormal expression of Hax‑1 may be associated with the development of the nervous system and with the pathophysiology of neurological diseases, including traumatic brain injury and cerebral ischemia. The present study reported temporal‑spatial patterns of Hax‑1 in rat retina following optic nerve crush (ONC). Using western blotting and double‑immunofluorescence, significant upregulation of Hax‑1 was observed in retinal ganglion cells (RGCs) in the retina following ONC. Increased Hax‑1 expression was demonstrated to be accompanied by upregulation of active‑caspase‑3 and HtrA2 following ONC. In addition, Hax-1 co‑localized with active caspase‑3 and HtrA2 in RGCs following ONC. Terminal deoxynucleotidyl transferase‑mediated biotinylated-dUTP nick‑end labeling staining suggested that Hax‑1 was involved in RGC apoptosis following ONC. Thus, these results suggested that Hax‑1 may participate in regulating RGC apoptosis via interacting with caspase‑3 and HtrA2 following ONC.