Sandra Johnen
RWTH Aachen University
GeneGenetic enhancementOphthalmologySleeping Beauty transposon systemMolecular biologyChemistryMacular degenerationPrimary (chemistry)RetinaBiocompatibilityRetinalRetinal degenerationChoroidal neovascularizationTransplantationTransposable elementCancer researchPEDFTransfectionPigmentMedicineBiologyCell biology
Publications 85
#1Claudia Ingensiep (RWTH Aachen University)
#2Kim Schaffrath (RWTH Aachen University)H-Index: 3
Last. Sandra Johnen (RWTH Aachen University)H-Index: 13
view all 0 authors...
Several eye diseases, for example, retinal artery occlusion, diabetic retinopathy, and glaucoma, are associated with retinal hypoxia. The lack of oxygen in the retina, especially in retinal ganglion cells (RGCs), causes cell damage up to cell degeneration and leads to blindness. Using multielectrode array recordings, an ex vivo hypoxia acute model was established to analyze the electrical activity of murine wild-type retinae under hypoxic stress conditions. Hypoxia was induced by exchanging the ...
#1Thais Bascuas (University of Geneva)H-Index: 5
#1Thais Bascuas (University of Geneva)
Last. Gabriele Thumann (University of Geneva)H-Index: 29
view all 7 authors...
Age-related macular degeneration (AMD) is the most frequent cause of blindness in patients >60 years, affecting ~30 million people worldwide. AMD is a multifactorial disease influenced by environmental and genetic factors, which lead to functional impairment of the retina due to retinal pigment epithelial (RPE) cell degeneration followed by photoreceptor degradation. An ideal treatment would include the transplantation of healthy RPE cells secreting neuroprotective factors to prevent RPE cell de...
#1Sandra JohnenH-Index: 13
#2Nina HarmeningH-Index: 5
Last. Gabriele ThumannH-Index: 29
view all 8 authors...
Our increasingly aging society leads to a growing incidence of neurodegenerative diseases. So far, the pathological mechanisms are inadequately understood, thus impeding the establishment of defined treatments. Cell-based additive gene therapies for the increased expression of a protective factor are considered as a promising option to medicate neurodegenerative diseases, such as age-related macular degeneration (AMD). We have developed a method for the stable expression of the gene encoding pig...
#1Jana Gehlen (Forschungszentrum Jülich)H-Index: 1
#2Stefan Esser (Forschungszentrum Jülich)
Last. Frank Müller (Forschungszentrum Jülich)H-Index: 30
view all 6 authors...
Purpose In RP, photoreceptors degenerate. Retinal prostheses are considered a suitable strategy to restore vision. In animal models of RP, a pathologic rhythmic activity seems to compromise the efficiency of retinal ganglion cell stimulation by an electrical prosthesis. We, therefore, strove to eliminate this pathologic activity. Methods Electrophysiologic recordings of local field potentials and spike activity of retinal ganglion cells were obtained in vitro from retinae of wild-type and rd10 m...
#1Anna-Marina van der Meer (RWTH Aachen University)H-Index: 1
#2Tanja Berger (RWTH Aachen University)H-Index: 2
Last. Peter Walter (RWTH Aachen University)H-Index: 135
view all 6 authors...
Purpose To investigate whether UV irradiation of the mouse eye can induce photoreceptor degeneration, producing a phenotype reminiscent of the rd10 mouse, left eyes of female C57Bl/6J mice were irradiated with a UV LED array (370 nm). A lens was placed between the cornea and LED, allowing illumination of about one-third of the retina. The short-term and long-term effects on the retina were evaluated. Methods First, a dose escalation study, in which corneal dosages between 2.8 and 9.3 J/cm2 were ...
1 CitationsSource
#1Sandra JohnenH-Index: 13
#2Horst HelbigH-Index: 19
Last. Peter WalterH-Index: 135
view all 4 authors...
#1Maria Hernandez (University of Navarra)H-Index: 8
#2Sergio Recalde (University of Navarra)H-Index: 17
Last. Patricia Fernandez-Robredo (University of Navarra)H-Index: 16
view all 19 authors...
Abstract Age-related macular degeneration (AMD) is a progressive retinal disorder, characterised by imbalanced pro- and anti-angiogenic signals. The aim of this study was to evaluate the effect of ex vivo cell-based gene therapy with stable expression of human pigment epithelium derived factor (PEDF) release using the non-viral Sleeping Beauty (SB100X) transposon system delivered by miniplasmids free of antibiotic resistance markers (pFAR4). Retinal pigment epithelial cells (RPEs) and iris pigme...
4 CitationsSource
#1Tibor Karl Lohmann (RWTH Aachen University)H-Index: 4
#2Florent Haiss (Pasteur Institute)H-Index: 2
Last. Peter Walter (RWTH Aachen University)H-Index: 25
view all 15 authors...
Background: The restoration of vision in blind patients suffering from degenerative retinal diseases like retinitis pigmentosa (RP) may be obtained by local electrical stimulation with retinal implants.a#13; In this study, a very large electrode array for retinal stimulation (VLARS) was introduced and tested regarding its safety in implantation and biocompatibility. Further, the array's stimulation capabilities were tested in an acute setting.a#13; Material and Method: The polyimide-based implan...
11 CitationsSource
#1Tibor Karl Lohmann (RWTH Aachen University)H-Index: 4
#2Cláudia Werner (RWTH Aachen University)H-Index: 24
Last. Kim Schaffrath (RWTH Aachen University)H-Index: 3
view all 10 authors...
1 Citations
#1Kim Schaffrath (RWTH Aachen University)H-Index: 3
#2Frank MüllerH-Index: 30
Last. Peter Walter (RWTH Aachen University)H-Index: 25
view all 6 authors...