Der Angiotensin-4-Rezeptor, IRAP als Bestandteil eines lokalen Angiotensin-Systems der Beta-Zelle

Das Renin-Angiotensin-System ist bekanntlich für die Blutdruckregulation von großer Bedeutung. Für das endokrine, Pankreas ist bekannt, dass auch hier ein Renin-Angiotensin-System existiert, welches verschiedene Zellfunktionen reguliert. Der Rezeptor für das Angiotensin-Abbauprodukt Angiotensin IV (AT4-Rezeptor) im endokrinen Pankreas wurde in dieser Arbeit ausführlich untersucht. In in vitro- sowie in vivo-Versuchen konnte gezeigt werden, dass der AT4-Rezeptor Bestandteil eines lokalen Angiotensin-Systems der Beta Zelle ist und unter anderem die Calcium-Aufnahme sowie die Insulinsekretion der Beta-Zelle moduliert. Die Ergebnisse dieser Arbeit geben Hinweise auf die Postrezeptorkaskade des AT4-Rezeptors der Beta-Zelle und zeigen, dass Insulin ein mögliches Substrat der Aminopeptidasefunktion des Rezeptors darstellt. Angiotensin IV ist daher eine interessante Verbindungen, die eine wichtige Rolle im Glukosestoffwechsel einnimmt

Elevation of the antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline: a blood pressure-independent beneficial effect of angiotensin I-converting enzyme inhibitors

Blockade of the renin-angiotensin system (RAS) is well recognized as an essential therapy in hypertensive, heart, and kidney diseases. There are several classes of drugs that block the RAS; these drugs are known to exhibit antifibrotic action. An analysis of the molecular mechanisms of action for these drugs can reveal potential differences in their antifibrotic roles. In this review, we discuss the antifibrotic action of RAS blockade with an emphasis on the potential importance of angiotensin I-converting enzyme (ACE) inhibition associated with the antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP)

Descemet membrane endothelial keratoplasty in complex eyes

BackgroundDescemet membrane endothelial keratoplasty (DMEK) has become the standard surgical treatment for Fuchs' endothelial corneal dystrophy (FECD) in Germany. In addition to classical FECD, there are endothelial disorders amenable to DMEK associated with complex changes in the anterior segment of the eye, such as anterior synechia of the iris, larger iris defects, after glaucoma surgery, after vitrectomy and after trauma.ObjectiveThis article provides an overview of the possibilities to treat patients with complex anterior segment situations in the presence of corneal endothelial decompensation with DMEK.Material and methodsDescription of problems and current surgical techniques when performing DMEK in complex situations.ResultsReconstruction of the iris or the iris/lens diaphragm often needs to be performed either simultaneously or in aprevious operation to treat patients with complex anterior segment alterations with DMEK. Both very shallow and very deep anterior chambers pose amajor problem. A DMEK graft from older donors (above 70years) is prone to less rolling and should be preferred in patients with adeep anterior chamber (e.g. after vitrectomy). The graft size should also be adapted to the available space, e.g. asmaller graft diameter should be selected for eyes with anterior synechia.ConclusionThere are only afew evaluations of DMEK under complex conditions; however, it appears that the rate of secondary graft failure, endothelial cell loss and the rebubbling rate are increased in this very heterogeneous group of diseases. Further studies are needed to identify risk factors for anegative progression after DMEK in complex eyes

Technique of Descemet membrane endothelial keratoplasty (DMEK). Video article

BackgroundDescemet membrane endothelial keratoplasty (DMEK) selectively removes diseased corneal endothelium and Descemet membrane and replaces them with healthy donor tissue. The DMEK technique represents the current gold standard for the treatment of corneal endothelial dysfunction.MethodsIn this article the surgical technique for DMEK is presented by means of avideo. The indications for surgery, patient education, anesthesia and patient positioning, postoperative treatment as well as possible complications and their management are described.ResultsThe DMEK can be applied for the treatment of awide range of corneal endothelial disorders. In addition to the operative implementation, the basis for the outstanding results of the surgical procedure are careful donor-patient allocation, thorough examination and follow-up of all patients and experience of the surgeon.ConclusionThe use of DMEK is asafe and effective procedure for the treatment of corneal endothelial dysfunction. Astandardized and individualized procedure provides the basis for optimal results compared to all previous transplantation procedures

Boston type I keratoprosthesis implantation technique. Video article

BackgroundKeratoprosthetics refer to the replacement of human corneal tissue with an artificially produced exchange product. The most widely implanted keratoprosthesis worldwide is the Boston TypeI Keratoprosthesis (BI-KPro, Massachusetts Eye and Ear Infirmary, Boston, MA, USA).MethodsThis video article demonstrates the surgical technique of BI-KPro implantation as routinely performed at this institution. In addition, an overview of the surgical indications, patient consent, anesthesia and positioning, postoperative treatment and complications as well as the evidence of the technique is provided in the article based on experience with 31 BI-KPro implantations.ResultsThe indications for BI-KPro primarily include patients in ahigh-risk keratoplasty setting particularly after repeatedly failed keratoplasty. A thorough patient examination and assessment of the indications as well as detailed disclosure of information to the patient about the individual prognosis, the risk profile, the postoperative therapy and follow-up enable apositive postoperative result.ConclusionThe BI-KPro provides an established and relatively standardized option for surgical treatment of eyes in ahigh-risk keratoplasty setting. Patients should be preoperatively informed with respect to the individual prognosis, complication profile and life-long follow-up