scholarly journals Optimisation of a Novel Bio-Substrate as a Treatment for Atrophic Age-Related Macular Degeneration

2019 ◽  
Author(s):  
Rachel McCormick ◽  
Ian Pearce ◽  
Stephen Kaye ◽  
Atikah Haneef
Keyword(s):  
Cell Culture ◽  
Macular Degeneration ◽  
Glycolic Acid ◽  
Culture Media ◽  
Plga Nanoparticles ◽  
Age Related Macular Degeneration ◽  
Cell Culture Media ◽  
Rpe Cells ◽  
Age Related ◽  
Waste Exchange

AbstractAtrophic age-related macular degeneration (AMD) is the most common form of AMD accounting for 90% of patients. During atrophic AMD the waste/exchange pathway between the blood supply (choroid) and the retinal pigment epithelium (RPE) is compromised. This results in atrophy and death of the RPE cells and subsequently the photoreceptors leading to central blindness. Although the mechanisms behind AMD are unknown, the growth of fatty deposits known as drusen, have been shown to play a role in the disease. There is currently no treatment or cure for atrophic AMD. Much research focuses on developing a synthetic substrate in order to transplant healthy cells to the native Bruch’s membrane (BM), however, the diseased native BM and related structures still leave the potential for transplanted cells to succumb to disease. In this work we electrospun poly(ethylene terephthalate) (PET) to fabricate a nanofibrous cytocompatible synthetic BM. The apical surface of the membrane was cultured with ARPE-19 cells and the basal surface was decorated with poly(lactic acid-co-glycolic acid) (PLGA) or poly(glycolic acid) (PGA) degradable nanoparticles by electrospraying. The membrane exhibited hydrophilicity, high tensile strength and structurally resembled the native BM. ARPE-19 cells were able to form a monolayer on the surface of the membrane and no cell invasion into the membrane was seen. The presence of both PLGA and PGA nanoparticles increased ARPE-19 cell metabolism but had no effect on cell viability. There was a decrease in pH of ARPE-19 cell culture media 7 days following culturing with the PLGA nanoparticles but this change was eliminated by 2 weeks; PGA nanoparticles had no effect on cell culture media pH. The fluorescent dye FITC was encapsulated into nanoparticles and showed sustained release from PLGA nanoparticles for two weeks and PGA nanoparticles for 1 day. Future work will focus on encapsulating biologically active moieties to target drusen. This would allow this novel bioactive substrate to be a potential treatment for atrophic AMD that would function two-fold: deliver the required monolayer of healthy RPE cells to the macula on a synthetic BM and remove diseased structures within the retina, restoring the waste/exchange pathway and preventing vision loss.

scholarly journals Ginsenoside-Rb1 Induces ARPE-19 Proliferation and Reduces VEGF Release

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Brandi S. Betts ◽  
Kalpana Parvathaneni ◽  
Bharat B. Yendluri ◽  
Jeffery Grigsby ◽  
Andrew T. C. Tsin
Keyword(s):  
Cell Proliferation ◽  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Ginseng Root ◽  
Root Extract ◽  
Ginsenoside Rb1 ◽  
Rpe Cells ◽  
Viable Cells ◽  
Age Related ◽  
Vegf Release

Rb1, a ginsenoside from ginseng root extract, possesses antiangiogenic effects, but its role on ocular cells has not been studied. We hypothesize that Rb1 inhibits the production of the angiogenic cytokine VEGF from ARPE-19 cells, leading to a significant reduction in the proliferation of ocular vasculatures. Data from our experiments show that Rb1 induced an increase in the number of ARPE cells in culture, while VEGF release (pg/10,000 viable cells) was significantly reduced. Treatment with VEGF and cotreatment with Rb1 and VEGF showed that this Rb1-induced cell proliferation was mediated by VEGF. Because VEGF from RPE plays a major role in promoting angiogenesis in ocular vasculatures. Our finding that Rb1 inhibits the release of VEGF from RPE cells suggests that Rb1 has a significant role in the eye to protect against angiogenic diseases such as age-related macular degeneration.

scholarly journals Dietary Polyphenols in Age-Related Macular Degeneration: Protection against Oxidative Stress and Beyond

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Elzbieta Pawlowska ◽  
Joanna Szczepanska ◽  
Ali Koskela ◽  
Kai Kaarniranta ◽  
Janusz Blasiak
Keyword(s):  
Oxidative Stress ◽  
Macular Degeneration ◽  
Retinal Pigment ◽  
Janus Kinase ◽  
Age Related Macular Degeneration ◽  
Hydroxyl Groups ◽  
Ros Scavenging ◽  
Rpe Cells ◽  
Dietary Polyphenols ◽  
Age Related

Age-related macular degeneration (AMD) is a multifactorial disease of the retina featured by degeneration and loss of photoreceptors and retinal pigment epithelium (RPE) cells with oxidative stress playing a role in its pathology. Although systematic reviews do not support the protective role of diet rich in antioxidants against AMD, dietary polyphenols (DPs) have been reported to have beneficial effects on vision. Some of them, such as quercetin and cyanidin-3-glucoside, can directly scavenge reactive oxygen species (ROS) due to the presence of two hydroxyl groups in their B ring structure. Apart from direct ROS scavenging, DPs can lower oxidative stress in several other pathways. Many DPs induce NRF2 (nuclear factor, erythroid 2-like 2) activation and expression of phase II enzymes that are under transcriptional control of this factor. DPs can inhibit A2E photooxidation in RPE cells, which is a source of oxidative stress. Anti-inflammatory action of DPs in RPE cells is associated with regulation of various interleukins and signaling pathways, including IL-6/JAK2 (Janus kinase 2)/STAT3. Some DPs can improve impaired cellular waste clearance, including AMD-specific deficient phagocytosis of the Aβ42 peptide and autophagy.

scholarly journals Protective Effects of Curcumin Ester Prodrug, Curcumin Diethyl Disuccinate against H2O2-Induced Oxidative Stress in Human Retinal Pigment Epithelial Cells: Potential Therapeutic Avenues for Age-Related Macular Degeneration

2019 ◽  
Vol 20 (13) ◽  
pp. 3367 ◽  
Author(s):  
Chawanphat Muangnoi ◽  
Umar Sharif ◽  
Pahweenvaj Ratnatilaka Na Bhuket ◽  
Pornchai Rojsitthisak ◽  
Luminita Paraoan
Keyword(s):  
Oxidative Stress ◽  
Macular Degeneration ◽  
Retinal Pigment ◽  
Parent Drug ◽  
Retinal Pigment Epithelial Cells ◽  
Age Related Macular Degeneration ◽  
Protective Effects ◽  
Rpe Cells ◽  
Age Related ◽  
Potent Drug

Oxidative stress-induced damage to the retinal pigmented epithelium (RPE), a specialised post-mitotic monolayer that maintains retinal homeostasis, contributes to the development of age-related macular degeneration (AMD). Curcumin (Cur), a naturally occurring antioxidant, was previously shown to have the ability to protect RPE cells from oxidative stress. However, poor solubility and bioavailability makes Cur a poor therapeutic agent. As prodrug approaches can mitigate these limitations, we compared the protective properties of the Cur prodrug curcumin diethyl disuccinate (CurDD) against Cur in relation to oxidative stress induced in human ARPE-19 cells. Both CurDD and Cur significantly decreased H2O2-induced reactive oxygen species (ROS) production and protected RPE cells from oxidative stress-induced death. Both drugs exerted their protective effects through the modulation of p44/42 (ERK) and the involvement of downstream molecules Bax and Bcl-2. Additionally, the expression of antioxidant enzymes HO-1 and NQO1 was also enhanced in cells treated with CurDD and Cur. In all cases, CurDD was more effective than its parent drug against oxidative stress-induced damage to ARPE-19 cells. These findings highlight CurDD as a more potent drug compared to Cur against oxidative stress and indicate that its protective effects are exerted through modulation of key apoptotic and antioxidant molecular pathways.

Engineered safe and immune-tolerant ‘designer’ rpe cells towards the treatment of age-related macular degeneration

Cytotherapy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. S19
Author(s):  
S. Hacibekiroglu ◽  
E. Jong ◽  
J. Tang ◽  
T. Oussenko ◽  
M. Ho ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Rpe Cells ◽  
Age Related ◽  
Immune Tolerant

scholarly journals Detrimental Effects of UVB on Retinal Pigment Epithelial Cells and Its Role in Age-Related Macular Degeneration

2020 ◽  
Vol 2020 ◽  
pp. 1-29 ◽  
Author(s):  
Camille Keisha Mahendra ◽  
Loh Teng Hern Tan ◽  
Priyia Pusparajah ◽  
Thet Thet Htar ◽  
Lay-Hong Chuah ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Bioactive Compounds ◽  
Retinal Pigment Epithelial ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Cumulative Exposure ◽  
Rpe Cells ◽  
Pigment Epithelial ◽  
Age Related

Retinal pigment epithelial (RPE) cells are an essential part of the human eye because they not only mediate and control the transfer of fluids and solutes but also protect the retina against photooxidative damage and renew photoreceptor cells through phagocytosis. However, their function necessitates cumulative exposure to the sun resulting in UV damage, which may lead to the development of age-related macular degeneration (AMD). Several studies have shown that UVB induces direct DNA damage and oxidative stress in RPE cells by increasing ROS and dysregulating endogenous antioxidants. Activation of different signaling pathways connected to inflammation, cell cycle arrest, and intrinsic apoptosis was reported as well. Besides that, essential functions like phagocytosis, osmoregulation, and water permeability of RPE cells were also affected. Although the melanin within RPE cells can act as a photoprotectant, this photoprotection decreases with age. Nevertheless, the changes in lens epithelium-derived growth factor (LEDGF) and autophagic activity or application of bioactive compounds from natural products can reverse the detrimental effect of UVB. Additionally, in vivo studies on the whole retina demonstrated that UVB irradiation induces gene and protein level dysregulation, indicating cellular stress and aberrations in the chromosome level. Morphological changes like retinal depigmentation and drusen formation were noted as well which is similar to the etiology of AMD, suggesting the connection of UVB damage with AMD. Therefore, future studies, which include mechanism studies via in vitro or in vivo and other potential bioactive compounds, should be pursued for a better understanding of the involvement of UVB in AMD.

scholarly journals Control of Complement Activation by the Long Pentraxin PTX3: Implications in Age-Related Macular Degeneration

2020 ◽  
Vol 11 ◽  
Author(s):  
Matteo Stravalaci ◽  
Francesca Davi ◽  
Raffaella Parente ◽  
Marco Gobbi ◽  
Barbara Bottazzi ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Complement Activation ◽  
Hot Spot ◽  
Alternative Pathway ◽  
Retinal Pigment ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Complement Factor ◽  
Rpe Cells ◽  
Age Related

Dysregulation of the complement system is central to age-related macular degeneration (AMD), the leading cause of blindness in the developed world. Most of the genetic variation associated with AMD resides in complement genes, with the greatest risk associated with polymorphisms in the complement factor H (CFH) gene; factor H (FH) is the major inhibitor of the alternative pathway (AP) of complement that specifically targets C3b and the AP C3 convertase. Long pentraxin 3 (PTX3) is a soluble pattern recognition molecule that has been proposed to inhibit AP activation via recruitment of FH. Although present in the human retina, if and how PTX3 plays a role in AMD is still unclear. In this work we demonstrated the presence of PTX3 in the human vitreous and studied the PTX3-FH-C3b crosstalk and its effects on complement activation in a model of retinal pigment epithelium (RPE). RPE cells cultured in inflammatory AMD-like conditions overexpressed the PTX3 protein, and up-regulated AP activating genes. PTX3 bound RPE cells in a physiological setting, however this interaction was reduced in inflammatory conditions, whereby PTX3 had no complement-inhibiting activity on inflamed RPE. However, on non-cellular surfaces, PTX3 formed a stable ternary complex with FH and C3b that acted as a “hot spot” for complement inhibition. Our findings suggest a protective role for PTX3 in response to complement dysregulation in AMD and point to a novel mechanism of complement regulation by this pentraxin with potential implications in pathology and pharmacology of AMD.

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