Retinal Pigment Epithelium Transplantation: Past, Present, and Future

Retinal pigment epithelium (RPE) is a monolayer of cells situated between photoreceptors and the underlying choroid. It is essential for normal retinal function. Damaged RPE is associated with diseases such as age-related macular degeneration, Stargardt’s macular dystrophy, and retinitis pigmentosa. RPE cells can easily be visualized in vivo, sustainable in vitro, and differentiated from stem cells with a relatively straightforward protocol. Due to these properties and the clinical significance of this epithelium in various retinal diseases, RPE transplantation as a treatment modality has gained considerable interest in the last decade. This paper presents the main techniques for RPE transplantation and discusses recent clinically relevant publications

Seasonal variations in presenting symptoms and signs of dry eye disease in Norway

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Cyclosporine : A review article

Cyclosporine is a immunosuppressive agent used in solid organ and bone marrow transplantation worldwide. Its discovery in 1972 was revolutionary in transplant medicine because of the need to suppress the immune system without affecting other cells substantially. The biochemical effect of calcineurin inhibitors, including cyclosporine and tacrolimus, is the inhibition of T-cell activation through various mechanisms. Even though cyclosporine was considered less cytotoxic, some adverse effects were revealed later. Nephrotoxicity is a well known adverse effect, probably induced by the vasoconstrictive effect of cyclosporine. In addition, this article describes cardiovascular, gastrointestinal and neurological adverse effects. Disturbances in blood glucose, lipids and electrolytes have also been reported. A narrow therapeutic range, in addition to interactions with Cyt-P450, makes careful monitoring of cyclosporine very important. Cyclosporine also have interactions with other drugs, such as calcium-inhibitors, carbamazepine and rifampine. The clinical use and efficacy have been described in transplantation of various solid organs as well as bone marrow transplantation. The results for cyclosporine and other immunosuppressive agents have been compared. As an example of cyclosporine-induced visual adverse effects, we also included a case report describing onset of visual adverse effects in a patient after 15 years of cyclosporine prophylaxis due to cardiac transplantation. These visual symptoms showed improvement on cessation of cyclosporine. Possible microangiopathic effects of cyclosporinehave been described, e.g. local endothelin-1 (ET-1) activity, effects on nitric oxide (NO), superoxides (O2-) and interactions on the sympathetic nervous system. Finally, future aspects and the new immunosuppressive agent known as the mTOR inhibitors have been discussed. Especially the need to use cyclosporine sparing regimens in the future has drawn much attention. Most importantly this is due to the nephrotoxic effect of cyclosporine

Effect of Storage Temperature on Key Functions of Cultured Retinal Pigment Epithelial Cells

Purpose. Replacement of the diseased retinal pigment epithelium (RPE) with cells capable of performing the specialized functions of the RPE is the aim of cell replacement therapy for treatment of macular degenerative diseases. A storage method for RPE is likely to become a prerequisite for the establishment of such treatment. Herein, we analyze the effect of storage temperature on key functions of cultured RPE cells. Methods. Cultured ARPE-19 cells were stored in Minimum Essential Medium at 4°C, 16°C, and 37°C for seven days. Total RNA was isolated and the gene expression profile was determined using DNA microarrays. Comparison of the microarray expression values with qRT-PCR analysis of selected genes validated the results. Results. Expression levels of several key genes involved in phagocytosis, pigment synthesis, the visual cycle, adherens, and tight junctions, and glucose and ion transport were maintained close to control levels in cultures stored at 4°C and 16°C. Cultures stored at 37°C displayed regulational changes in a larger subset of genes related to phagocytosis, adherens, and tight junctions. Conclusion. RPE cultures stored at 4°C and 16°C for one week are capable of maintaining the expression levels of genes important for key RPE functions close to control levels

Concise Review: Comparison of Culture Membranes Used for Tissue Engineered Conjunctival Epithelial Equivalents

The conjunctival epithelium plays an important role in ensuring the optical clarity of the cornea by providing lubrication to maintain a smooth, refractive surface, by producing mucins critical for tear film stability and by protecting against mechanical stress and infectious agents. A large number of disorders can lead to scarring of the conjunctiva through chronic conjunctival inflammation. For controlling complications of conjunctival scarring, surgery can be considered. Surgical treatment of symblepharon includes removal of the scar tissue to reestablish the deep fornix. The surgical defect is then covered by the application of a tissue substitute. One obvious limiting factor when using autografts is the size of the defect to be covered, as the amount of healthy conjunctiva is scarce. These limitations have led scientists to develop tissue engineered conjunctival equivalents. A tissue engineered conjunctival epithelial equivalent needs to be easily manipulated surgically, not cause an inflammatory reaction and be biocompatible. This review summarizes the various substrates and membranes that have been used to culture conjunctival epithelial cells during the last three decades. Future avenues for developing tissue engineered conjunctiva are discussed

Tromboseprofylakse ved innsettelse av total hofteprotese- en KLoK-oppgave

Bakgrunn og kunnskapsgrunnlag: Gjennom studiet har vi lært om tromboemboliske hendelser og konsekvensene av dem. Videre vet vi at innsettelse av total hofteleddsprotese er et vanlig ortopedisk inngrep, rundt 7000 førstegangsinnsettelser årlig. Inngrep i hofteleddsregionen regnes for å være høyrisikoinngrep med tanke på utvikling av venøs tromboembolisme (VTE) i det postoperative forløpet. Bruk av lavmolekylært heparin har vist seg å forebygge VTE, men hvor lenge dette bør brukes har vært mer omdiskutert. Studier tyder imidlertid på at man får en reduksjon av antall VTE ved langvarig profylakse på rundt 4 uker uten at blødningsrisikoen øker. Bruk av kompresjonsstrømper er dårligere dokumentert. Ved ulike ortopediske avdelinger er det en rekke ulike retningslinjer for bruken av tromboseprofylakse postoperativt. Vi ønsker å implementere en felles nasjonal retningslinje basert på dokumentert kunnskap. Begrunnet tiltak, metode og organisering: Det er viktig at ledelsen på avdelingen blir involvert i prosjektet fra første stund. Selve arbeidet bør delegeres til en dedikert medarbeider, og flere faggrupper bør involveres. Med bakgrunn i forskning vedrørende effektive tiltak innen kvalitetsforbedring, har vi funnet at en multifasettert intervensjon er det som vil fungere best. Det er viktig med kartlegging av barrierer for implementeringen. Deretter er det nødvendig med informasjon til de involverte om nye retningslinjer. For at disse skal følges opp i det daglige vil en sjekkliste kunne bidra til økt bevissthet. Tilbakemelding til de ansatte i avdelingen med tanke på hvor ”flinke” de er til å følge opp retningslinjene og andelen pasienter som får profylakse i henhold til retningslinjen vil være nødvendig. Dette kan også benyttes som en ”konkurranse” mellom de ulike sykehusene. Underveis vil det være nødvendig med evaluering av tiltakene og eventuelle justeringer. Resultater / Vurdering: Vi mener at dette kvalitetsforbedrings-prosjektet vil kunne la seg gjennomføre på alle ortopediske avdelinger. Ut fra lokale forhold og barrierer bør det gjøres tilpasninger. Det er til det beste for pasientene at det etableres en nasjonal retningslinje, da dette sikrer alle lik behandling

Reliability of corneal dynamic scheimpflug analyser measurements in virgin and post-PRK eyes

Purpose To determine the measurement reliability of CorVis ST, a dynamic Scheimpflug analyser, in virgin and post-photorefractive keratectomy (PRK) eyes and compare the results between these two groups. Methods Forty virgin eyes and 42 post-PRK eyes underwent CorVis ST measurements performed by two technicians. Repeatability was evaluated by comparing three consecutive measurements by technician A. Reproducibility was determined by comparing the first measurement by technician A with one performed by technician B. Intraobserver and interobserver intraclass correlation coefficients (ICCs) were calculated. Univariate analysis of covariance (ANCOVA) was used to compare measured parameters between virgin and post-PRK eyes. Results The intraocular pressure (IOP), central corneal thickness (CCT) and 1st applanation time demonstrated good intraobserver repeatability and interobserver reproducibility (ICC≧0.90) in virgin and post-PRK eyes. The deformation amplitude showed a good or close to good repeatability and reproducibility in both groups (ICC≧0.88). The CCT correlated positively with 1st applanation time (r = 0.437 and 0.483, respectively, p<0.05) and negatively with deformation amplitude (r = −0.384 and −0.375, respectively, p<0.05) in both groups. Compared to post-PRK eyes, virgin eyes showed longer 1st applanation time (7.29±0.21 vs. 6.96±0.17 ms, p<0.05) and lower deformation amplitude (1.06±0.07 vs. 1.17±0.08 mm, p<0.05). Conclusions CorVis ST demonstrated reliable measurements for CCT, IOP, and 1st applanation time, as well as relatively reliable measurement for deformation amplitude in both virgin and post-PRK eyes. There were differences in 1st applanation time and deformation amplitude between virgin and post-PRK eyes, which may reflect corneal biomechanical changes occurring after the surgery in the latter

Bioactive titaminates from molecular layer deposition

Organic–inorganic hybrid materials are an emerging class of materials suitable for deposition by the molecular layer deposition (MLD) technique. Their toolbox is now expanded to include linkers of amino acids, which when combined with titanium form materials that can be termed titaminates, based on the amine and carboxylates present in the amino acids being used as linkers. This is a class of compounds with high potential as bioactive materials, containing essential amino acids and biocompatible titanium. The films have been prepared by combining titanium tetra-isopropoxide (TTIP) with glycine and L-aspartic acid. L-Arginine has also been used, however, without success. Hybrid films of TTIP and succinic acid were also investigated as a comparison to L-aspartic acid due to their structural similarities. All systems show self-limiting growth with a reduction in the growth rate with increasing temperature. The as-deposited films are amorphous, have low surface roughness, exhibit a hydrophilic nature as measured by a goniometer, and bear indications of some porosity towards water. Films based on glycine and L-aspartic acid have been used as substrates for growth of epithelial cells (rat goblet cells) where their proliferation has been monitored. The cell proliferation was significantly increased on these substrates compared to uncoated coverslips

Effect of storage temperature on cultured epidermal cell sheets stored in xenobiotic-free medium

Cultured epidermal cell sheets (CECS) are used in regenerative medicine in patients with burns, and have potential to treat limbal stem cell deficiency (LSCD), as demonstrated in animal models. Despite widespread use, short-term storage options for CECS are limited. Advantages of storage include: flexibility in scheduling surgery, reserve sheets for repeat operations, more opportunity for quality control, and improved transportation to allow wider distribution. Studies on storage of CECS have thus far focused on cryopreservation, whereas refrigeration is a convenient method commonly used for whole skin graft storage in burns clinics. It has been shown that preservation of viable cells using these methods is variable. This study evaluated the effect of different temperatures spanning 4°C to 37°C, on the cell viability, morphology, proliferation and metabolic status of CECS stored over a two week period in a xenobiotic–free system. Compared to non-stored control, best cell viability was obtained at 24°C (95.2±9.9%); reduced cell viability, at approximately 60%, was demonstrated at several of the temperatures (12°C, 28°C, 32°C and 37°C). Metabolic activity was significantly higher between 24°C and 37°C, where glucose, lactate, lactate/glucose ratios, and oxygen tension indicated increased activation of the glycolytic pathway under aerobic conditions. Preservation of morphology as shown by phase contrast and scanning electron micrographs was best at 12°C and 16°C. PCNA immunocytochemistry indicated that only 12°C and 20°C allowed maintenance of proliferative function at a similar level to non-stored control. In conclusion, results indicate that 12°C and 24°C merit further investigation as the prospective optimum temperature for short-term storage of cultured epidermal cell sheets