Reduced Retinal Degeneration in an Oxidative Stress Organ Culture Model through an iNOS-Inhibitor

Mueller‐Buehl, Ana M.; Tsai, Teresa; Hurst, José; Theiß, Carsten; Peters, Laura; Hofmann, Lisa; Herms, Fenja; Kuehn, Sandra; Schnichels, Sven; Joachim, Stephanie C.

doi:10.3390/biology10050383

Cited by 13 publications

(14 citation statements)

References 56 publications

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“…In total, for each staining, six cross-sections per retina were analyzed. We used n = 8/group/point in time for (immuno-) histological staining [ 39 ]. Retinas were stained with hematoxylin and eosin (H and E) using established protocols to measure the thickness of retinal layers via ZEN 2012-imaging-software (blue edition, ZEISS, Oberkochen, Germany) [ 8 , 40 ].…”

Section: Methodsmentioning

confidence: 99%

Hypoxic Processes Induce Complement Activation via Classical Pathway in Porcine Neuroretinas

Mueller‐Buehl

Buehner

Pfarrer

et al. 2021

Cells

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Considering the fact that many retinal diseases are yet to be cured, the pathomechanisms of these multifactorial diseases need to be investigated in more detail. Among others, oxidative stress and hypoxia are pathomechanisms that take place in retinal diseases, such as glaucoma, age-related macular degeneration, or diabetic retinopathy. In consideration of these diseases, it is also evidenced that the immune system, including the complement system and its activation, plays an important role. Suitable models to investigate neuroretinal diseases are organ cultures of porcine retina. Based on an established model, the role of the complement system was studied after the induction of oxidative stress or hypoxia. Both stressors led to a loss of retinal ganglion cells (RGCs) accompanied by apoptosis. Hypoxia activated the complement system as noted by higher C3+ and MAC+ cell numbers. In this model, activation of the complement cascade occurred via the classical pathway and the number of C1q+ microglia was increased. In oxidative stressed retinas, the complement system had no consideration, but strong inflammation took place, with elevated TNF, IL6, and IL8 mRNA expression levels. Together, this study shows that hypoxia and oxidative stress induce different mechanisms in the porcine retina inducing either the immune response or an inflammation. Our findings support the thesis that the immune system is involved in the development of retinal diseases. Furthermore, this study is evidence that both approaches seem suitable models to investigate undergoing pathomechanisms of several neuroretinal diseases.

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Section: Methodsmentioning

confidence: 99%

Hypoxic Processes Induce Complement Activation via Classical Pathway in Porcine Neuroretinas

Mueller‐Buehl

Buehner

Pfarrer

et al. 2021

Cells

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“…This supports the assumption that our co-cultivation model provides an option to achieve a preservation of the delicate photoreceptor cells in vitro. Under pathological conditions, iNOS was produced and caused a more severe pathophysiological response aiming in retinal degeneration [ 60 , 61 , 62 ]. In the current study, we did not detect any alteration in the amount of iNOS + and iNOS + + Iba1 + cells in the neuroretina and distinct layers in the co-culture and conditioned medium samples compared to the control ones.…”

Section: Discussionmentioning

confidence: 99%

“…In the current study, we did not detect any alteration in the amount of iNOS + and iNOS + + Iba1 + cells in the neuroretina and distinct layers in the co-culture and conditioned medium samples compared to the control ones. Mueller-Buehl et al demonstrated a better preservation of porcine retina samples in an organotypic oxidative stress model by adding an iNOS-inhibitor [ 62 ]. The lacking induction of iNOS and microglial activation might indicate homeostasis of the neuroretina in culture.…”

Section: Discussionmentioning

confidence: 99%

Impact of Primary RPE Cells in a Porcine Organotypic Co-Cultivation Model

et al. 2022

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The pathological events of age-related macular degeneration are characterized by degenerative processes involving the photoreceptor cells, retinal pigment epithelium (RPE), and the Bruch’s membrane as well as choroidal alterations. To mimic in vivo interactions between photoreceptor cells and RPE cells ex vivo, complex models are required. Hence, the aim of this study was to establish a porcine organotypic co-cultivation model and enlighten the interactions of photoreceptor and RPE cells, with a special emphasis on potential neuroprotective effects. Porcine neuroretina explants were cultured with primary porcine RPE cells (ppRPE) or medium derived from these cells (=conditioned medium). Neuroretina explants cultured alone served as controls. After eight days, RT-qPCR and immunohistology were performed to analyze photoreceptors, synapses, macroglia, microglia, complement factors, and pro-inflammatory cytokines (e.g., IL1B, IL6, TNF) in the neuroretina samples. The presence of ppRPE cells preserved photoreceptors, whereas synaptical density was unaltered. Interestingly, on an immunohistological as well as on an mRNA level, microglia and complement factors were comparable in all groups. Increased IL6 levels were noted in ppRPE and conditioned medium samples, while TNF was only upregulated in the ppRPE group. IL1B was elevated in conditioned medium samples. In conclusion, a co-cultivation of ppRPE cells and neuroretina seem to have beneficial effects on the neuroretina, preserving photoreceptors and maintaining synaptic vesicles in vitro. This organotypic co-cultivation model can be used to investigate the complex interactions between the retina and RPE cells, gain further insight into neurodegenerative pathomechanisms occurring in retinal diseases, and evaluate potential therapeutics.

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“…Nitric oxide can also be beneficial or detrimental depending on concentration. While low levels of NO are necessary for signaling, higher concentrations can be harmful to neurons (Singh et al, 2019;Mueller-Buehl et al, 2021). In the retina, small concentrations of NO are utilized for light adaptation, visual processing, and amplification of visual responses in various retinal cell types (Vielma et al, 2012;Mueller-Buehl et al, 2021).…”

Section: The Role Of Ros In the Healthy Brain And Retinamentioning

confidence: 99%

Oxidative stress in the brain and retina after traumatic injury

2023

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The brain and the retina share many physiological similarities, which allows the retina to serve as a model of CNS disease and disorder. In instances of trauma, the eye can even indicate damage to the brain via abnormalities observed such as irregularities in pupillary reflexes in suspected traumatic brain injury (TBI) patients. Elevation of reactive oxygen species (ROS) has been observed in neurodegenerative disorders and in both traumatic optic neuropathy (TON) and in TBI. In a healthy system, ROS play a pivotal role in cellular communication, but in neurodegenerative diseases and post-trauma instances, ROS elevation can exacerbate neurodegeneration in both the brain and the retina. Increased ROS can overwhelm the inherent antioxidant systems which are regulated via mitochondrial processes. The overabundance of ROS can lead to protein, DNA, and other forms of cellular damage which ultimately result in apoptosis. Even though elevated ROS have been observed to be a major cause in the neurodegeneration observed after TON and TBI, many antioxidants therapeutic strategies fail. In order to understand why these therapeutic approaches fail further research into the direct injury cascades must be conducted. Additional therapeutic approaches such as therapeutics capable of anti-inflammatory properties and suppression of other neurodegenerative processes may be needed for the treatment of TON, TBI, and neurodegenerative diseases.

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Reduced Retinal Degeneration in an Oxidative Stress Organ Culture Model through an iNOS-Inhibitor

Cited by 13 publications

References 56 publications

Hypoxic Processes Induce Complement Activation via Classical Pathway in Porcine Neuroretinas

Hypoxic Processes Induce Complement Activation via Classical Pathway in Porcine Neuroretinas

Impact of Primary RPE Cells in a Porcine Organotypic Co-Cultivation Model

Oxidative stress in the brain and retina after traumatic injury

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