Resvega, a Nutraceutical Preparation, Affects NFκB Pathway and Prolongs the Anti-VEGF Effect of Bevacizumab in Undifferentiated ARPE-19 Retina Cells

Lycium barbarum polysaccharide inhibits retinal neovascularization and inflammation in vitro and in vivo

AIM

To explore the effect and mechanism of Lycium barbarum polysaccharide (LBP) inhibiting retinal neovascularization.

METHODS

In vitro tests were performed on human retinal microvascular endothelial cells (HRECs) from three groups, including control group (normal oxygen), hypoxic group (hypoxia at 37°C, 1% O2, 5% CO2, and 94% N2), and LBP group (hypoxic group with LBP 100 µg/mL). In vivo experiments, C57 mice were divided into three groups: control group (normal rearing group), the oxygen-induced ischemic retinopathy (OIR) group, and the OIR with 50 mg/kg LBP group. Retinal neovascularization was observed by fluorescein angiography and quantified. Retinal thickness was evaluated by Hematoxylin and eosin (HE) stain. The expression of epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K), mammalian target of rapamycin (mTOR), phosphorylated mammalian target of rapamycin (p-mTOR), protein kinase B (AKT), phosphorylated protein kinase B (p-AKT), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS), and tumor necrosis factor-α (TNF-α) in each group were analyzed by Western blot. IL-1β level in retina was analyzed using immunohistochemical staining.

RESULTS

The increased area of neovascular clusters in OIR mice was significantly decreased by LBP. Retinal thickness of OIR mice was significantly thinner compared with normal oxygenated mice and was increased in LBP group. Compared with those in the hypoxic groups, Western blotting of HRECs and retinal tissues revealed that the expression of EGFR, PI3K, p-mTOR, p-AKT, IL-1β, iNOS, and TNF-α decreased in the LBP group but was still greater than that in control group. Moreover, IL-1β was reduced in retinal sections treated with LBP. In the scratch test, the cell migration of the hypoxic group was significantly greater than that of the control group, while LBP treatment attenuated this increase in migration.

CONCLUSION

LBP reduces retinal neovascularization and inflammation in vivo and inhibits the migration of HRECs in vitro by regulating the EGFR/PI3K/Akt/mTOR signaling pathway.

Resveratrol Supplementation in Wet AMD: Association With Fewer Intravitreal Injections and Reduced Macular Fibrosis

Purpose

To evaluate the 2-year outcomes of resveratrol oral supplement given as an adjunctive treatment in patients with wet age-related macular degeneration (AMD) that were treated with intravitreal injections of aflibercept.

Patients and Methods

In our retrospective study, 50 treatment-naïve patients suffering from wet-AMD were included. They were assigned to two subgroups of 25 patients each. Every participant was treated according to "Pro Re Nata" protocol; 3 monthly intravitreal injections of 2.0 mg aflibercept were applied followed by injections according to need. The patients in the second group also consumed daily two tablets of resveratrol enriched oral supplement (60 mg of resveratrol in total). For 2 years, the patients were monthly assessed with best corrected visual acuity (BCVA) measurement, fundus autofluorescence, optical coherence tomography (OCT) scans and OCT-angiography. The main endpoints were the change of BCVA, the number of anti-VEGF injections, the change of central foveal thickness values, and the expansion or new development of fibrosis.

Results

Between the studied groups, no significant differences were detected in the baseline demographic and clinical data (p>0.05 for all). Over the 24-month study period, both BCVA and central foveal thickness values did not differ significantly between the two groups. As for the number of applied injections, they were significantly fewer in the group of patients that were treated with the resveratrol supplement (9.32±1.37 vs 7.40±1.88, p<0.001). Notably, the frequency of fibrosis progression was significantly lower in the resveratrol group (p=0.04).

Conclusion

In conclusion, our findings suggest that resveratrol oral supplement could be considered as a useful adjunctive aid to the established treatment in cases suffering from wet AMD, highlighting the superiority of the combination treatment regimen, since it was accompanied by lower rates of both intravitreal aflibercept injections and progression of macular fibrosis.

The Past and Future of Angiogenesis as a Target for Cancer Therapy and Prevention

Cancer growth is dependent on angiogenesis, the formation of new blood vessels, which represents a hallmark of cancer. After this concept was established in the 1970s, inhibition of tumor development and metastases by blocking the neoangiogenic process has been an important approach to the treatment of tumors. However, antiangiogenic therapies are often administered when cancer has already progressed. The key to reducing the cancer burden is prevention. We noticed 20 years ago that a series of possible cancer chemopreventive agents showed antiangiogenic properties when tested in experimental models. This article reviews the relevant advances in the understanding of the rationale for targeting angiogenesis for cancer therapy, prevention, and interception and recently investigated substances with antiangiogenic activity that may be suitable for such strategies. Many compounds, either dietary derivatives or repurposed drugs, with antiangiogenic activity are possible tools for cancer angioprevention. Such molecules have a favorable safety profile and are likely to allow the prolonged duration necessary for an efficient preventive strategy. Recent evidence on mechanisms and possible use is described here for food derivatives, including flavonoids, retinoids, triterpenoids, omega fatty acids, and carotenoids from marine microorganisms. As examples, a number of compounds, including epigallocatechin, resveratrol, xanthohumol, hydroxytyrosol, curcumin, fenretinide, lycopene, fucoxanthin, and repurposed drugs, such as aspirin, β blockers, renin-angiotensin-aldosterone inhibitors, carnitines, and biguanides, are reviewed.

Recent Advances in Our Understanding of Age-Related Macular Degeneration: Mitochondrial Dysfunction, Redox Signaling, and the Complement System

Age-related macular degeneration (AMD) is a prevalent degenerative disorder of the central retina, which holds global significance as the fourth leading cause of blindness. The condition is characterized by a multifaceted pathophysiology that involves aging, oxidative stress, inflammation, vascular dysfunction, and complement activation. The complex interplay of these factors contributes to the initiation and progression of AMD. Current treatments primarily address choroidal neovascularization (CNV) in neovascular AMD. However, the approval of novel drug therapies for the atrophic and more gradual variant, known as geographic atrophy (GA), has recently occurred. In light of the substantial impact of AMD on affected individuals' quality of life and the strain it places on healthcare systems, there is a pressing need for innovative medications. This paper aims to provide an updated and comprehensive overview of advancements in our understanding of the etiopathogenesis of AMD. Special attention will be given to the influence of aging and altered redox status on mitochondrial dynamics, cell death pathways, and the intricate interplay between oxidative stress and the complement system, specifically in the context of GA. Additionally, this review will shed light on newly approved therapies and explore emerging alternative treatment strategies in the field. The objective is to contribute to the ongoing dialogue surrounding AMD, offering insights into the latest developments that may pave the way for more effective management and intervention approaches.

CX3CL1/CX3CR1 Signaling Mediated Neuroglia Activation Is Implicated in the Retinal Degeneration: A Potential Therapeutic Target to Prevent Photoreceptor Death

Purpose

Retinal degeneration (RD) is a large cluster of retinopathies that is characterized by the progressive photoreceptor death and visual impairments. CX3CL1/CX3CR1 signaling has been documented to mediate the microglia activation and gliosis reaction during neurodegeneration. We intend to verify whether the CX3CL1/CX3CR1 signaling is involved in the RD pathology.

Methods

A pharmacologically induced RD mice model was established. AZD8797, a CX3CR1 antagonist, was injected into the vitreous cavity of an RD model to modulate the neuroglia activation. Then, the experimental animals were subjected to functional, morphological, and behavioral analysis.

Results

The CX3CL1/CX3CR1 signaling mediated neuroglia activation was implicated in the photoreceptor demise of an RD model. Intravitreal injection of AZD8797 preserved the retinal structure and enhanced the photoreceptor survival through inhibiting the CX3CL1/CX3CR1 expressions. Fundus photography showed that the distribution of retinal vessel was clear, and the severity of lesions was alleviated by AZD8797. In particular, these morphological benefits could be translated into remarkable functional improvements, as evidenced by the behavioral test and electroretinogram (mf-ERG) examination. A mechanism study showed that AZD8797 mitigated the microglia activation and migration in the degenerative retinas. The Müller cell hyper-reaction and secondary gliosis response were also suppressed by AZD8797.

Conclusions

The neuroinflammation is implicated in the photoreceptor loss of RD pathology. Targeting the CX3CL1/CX3CR1 signaling may serve as an effective therapeutic strategy. Future refinements of these findings may cast light into the discovery of new medications for RD.

Anti(angiogenic) food components: can be a major source of bias in the investigation of angiogenesis inhibitors

Background

Natural and diet-derived angiogenesis inhibitors/promotors are widely found in diets. These compounds can in several ways impact the results of oncological research of angiogenesis inhibitors.

Methods

We very briefly overview some of the most important examples to show how these compounds can create a bias in current research of cancer. Implications of this expert opinion cover similar angiogenesis-related diseases.

Results

Significant intra-individual differences in terms of dietary intake and differential effect of food processing techniques result in differential bioactivity and bioavailability of these compounds. There are only a handful of validated dietary questionnaire to quantify natural angiogenesis inhibitors/promotors. A corollary consequence is that participants in non-randomized clinical trials will have different baseline levels of serum/plasma/tissue/organ diet-derived angiogenesis inhibitors/promotors. This will lead to creation of clinical uncertainty and a hidden bias and consequently creation of translational efficiency bias, sampling efficiency, and waste of resources. We call for developing and validating a semi-quantitative food frequency questionnaire (FFQ) to gather data on these agents, specifically designed for oncological research because there is a clear gap in the literature of oncology.

Conclusions

This might facilitate the discovery of better prognostic, diagnostic, preventive measures, and therapeutic agents for the management of different cancers. Implications of this paper cover similar settings like ophthalmologic research.

The Essential Role of Light-Induced Autophagy in the Inner Choroid/Outer Retinal Neurovascular Unit in Baseline Conditions and Degeneration

The present article discusses the role of light in altering autophagy, both within the outer retina (retinal pigment epithelium, RPE, and the outer segment of photoreceptors) and the inner choroid (Bruch's membrane, BM, endothelial cells and the pericytes of choriocapillaris, CC). Here autophagy is needed to maintain the high metabolic requirements and to provide the specific physiological activity sub-serving the process of vision. Activation or inhibition of autophagy within RPE strongly depends on light exposure and it is concomitant with activation or inhibition of the outer segment of the photoreceptors. This also recruits CC, which provides blood flow and metabolic substrates. Thus, the inner choroid and outer retina are mutually dependent and their activity is orchestrated by light exposure in order to cope with metabolic demand. This is tuned by the autophagy status, which works as a sort of pivot in the cross-talk within the inner choroid/outer retina neurovascular unit. In degenerative conditions, and mostly during age-related macular degeneration (AMD), autophagy dysfunction occurs in this area to induce cell loss and extracellular aggregates. Therefore, a detailed analysis of the autophagy status encompassing CC, RPE and interposed BM is key to understanding the fine anatomy and altered biochemistry which underlie the onset and progression of AMD.

MAPK Pathways in Ocular Pathophysiology: Potential Therapeutic Drugs and Challenges

Mitogen-activated protein kinase (MAPK) pathways represent ubiquitous cellular signal transduction pathways that regulate all aspects of life and are frequently altered in disease. Once activated through phosphorylation, these MAPKs in turn phosphorylate and activate transcription factors present either in the cytoplasm or in the nucleus, leading to the expression of target genes and, as a consequence, they elicit various biological responses. The aim of this work is to provide a comprehensive review focusing on the roles of MAPK signaling pathways in ocular pathophysiology and the potential to influence these for the treatment of eye diseases. We summarize the current knowledge of identified MAPK-targeting compounds in the context of ocular diseases such as macular degeneration, cataract, glaucoma and keratopathy, but also in rare ocular diseases where the cell differentiation, proliferation or migration are defective. Potential therapeutic interventions are also discussed. Additionally, we discuss challenges in overcoming the reported eye toxicity of some MAPK inhibitors.