MMP-2 and MMP-9 secretion by rpe is stimulated by angiogenic molecules found in choroidal neovascular membranes.

PURPOSE: Matrix metalloproteinases (MMP)-2 and -9 play an important role in the pathogenesis of choroidal neovascularization (CNV). Retinal pigment epithelial cells (RPE) are an important source of MMPs in the outer retinal environment, however little is known about the local factors that modulate MMP secretion in these cells. The purpose of this study was to determine the effects of CNV involved growth factors and the extracellular matrix molecule fibronectin on MMP-2 and -9 secretion by cultured human RPE. METHODS: MMP-2 and -9 secretion was studied using gelatin zymography, Western blot, and ELISA assay of RPE culture supernatants. The effects of stimulating the cells for 36 hours with vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bGFG), tumor necrosis factor-alpha (TNF-alpha), or fibronectin (FN), all angiogenic factors found in CNV membranes, was determined. RESULTS: Resting RPE cells secreted MMP-2 but not MMP-9. Stimulation with TNF-alpha induced secretion of MMP-9 and increased the secretion of MMP-2. MMP-2 secretion was also increased by stimulation with FN and VEGF, but not bFGF. CONCLUSION: The results indicated that the angiogenic molecules VEGF, FN, and TNF-alpha stimulate MMP-2 and -9 secretion from RPE and thus further promote CNV.

Inhibitory effects of verapamil isomers on the proliferation of choroidal endothelial cells.

PURPOSE: To evaluate the effects of verapamil isomers on in vitro proliferation of bovine choroidal endothelial cells (CECs). MATERIALS AND METHODS: CECs were isolated from bovine eyes and cultured in endothelial growth medium (EGM). For the proliferation assays, CECs were exposed to verapamil isomers (0.1-100 microM) in EGM with 2% fetal bovine serum or basic fibroblast growth factor (bFGF) (10 ng/ml). After 72 h of incubation with the desired drug, the cellular proliferation was determined by an MTT assay and a BrdU assay. In addition, the drug toxicity on CECs stimulated with EGM was evaluated by cell counting with trypan blue. RESULTS: All verapamil isomers inhibited the bFGF- or medium-stimulated growth significantly in a concentration range of 10-40 microM without toxicity. No significant differences were seen between the inhibitory effects of the various isomers. Cell toxicity was detected at a concentration of 100 microM verapamil isomers on EGM-stimulated CECs. CONCLUSION: The results demonstrate the efficacy of all verapamil isomers in inhibiting CEC proliferation involved in the process of choroidal neovascularization. D: -(+)-Verapamil may be recommended for further in vivo evaluation in an animal model of exudative AMD; it has fewer systemic and local side effects because calcium channels are not blocked.

A selective cyclic integrin antagonist blocks the integrin receptors alphavbeta3 and alphavbeta5 and inhibits retinal pigment epithelium cell attachment, migration and invasion.

BACKGROUND: Proliferative vitreoretinopathy (PVR) is a leading cause of blindness after failed retinal reattachment surgery. PVR is characterized by the proliferation, migration and contraction of retinal pigmented epithelial cells (RPE), and these cellular responses are influenced by the expression and function of integrin receptors. The effect of a cyclic integrin antagonist containing the amino acid sequence Arg-Gly-Asp-D-Phe-Val (RGDfV), specific for the integrin receptors alphavbeta3 and alphavbeta5, was investigated on basic fibroblast growth factor (bFGF), platelet derived growth factor-BB (PDGF-BB), and serum induced human RPE proliferation, migration, invasion and attachment to the extracellular matrix. Furthermore, the effects of bFGF and PDGF-BB regulated expression of integrins alphavbeta3 and alphavbeta5 on RPE cells was examined. METHODS: The effect of a cyclic integrin antagonist and a control peptide (0.01 microg/ml to 300 microg/ml) was investigated on serum or cytokine (bFGF or PDGF-BB pretreatment) induced human fetal RPE cell proliferation by H3-thymidine uptake. The effect of the cyclic integrin antagonist on RPE cell attachment onto different extracellular matrices (laminin, collagen IV, fibronectin), RPE cell invasion stimulated by PDGF-BB or serum, and migration stimulated by PDGF-BB, vascular endothelial growth factor (VEGF) or serum was explored. PDGF-BB and bFGF modulation of the integrin receptors alphavbeta3 and alphavbeta5 was evaluated by flow cytometry. RESULTS: The integrin antagonist did not inhibit DNA synthesis stimulated by serum, bFGF, or PDGF-BB treatment. RPE attachment onto fibronectin was inhibited in a concentration range of 1-10 microg/ml (p < 0.05). Attachment of the RPE cells onto collagen IV and laminin was inhibited in a range of 3-10 microg/ml (p < 0.05). Serum and PDGF-BB stimulated migration was inhibited by the cyclic integrin antagonist in a concentration range of 1-10 microg/ml (p < 0.05). Furthermore, the cyclic integrin antagonist inhibited PDGF-BB stimulated RPE cell invasion through fibronectin (3 microg/ml: 66% inhibition, p < 0.001). In each of these experiments, the control peptides had no significant effects. PDGF-BB and bFGF pretreatment of RPE cells increased the expression of integrin receptors alphavbeta3 (bFGF: 1.9 fold, PDGF-BB: 2.3 fold) and alphavbeta5 (bFGF: 2.9 fold, PDGF-BB: 1.5 fold). CONCLUSION: A selective inhibition of the integrin receptors alphavbeta3 and alphavbeta5 through a cyclic integrin antagonist is able to inhibit RPE cell attachment, migration and invasion. Since these steps are of importance for the progression of PVR, a cyclic integrin antagonist should be further evaluated for the treatment of this disease.

[Self-Management of Anti-Obstructive Therapy for Severe COPD with a Subcutaneous Terbutaline Pump]. / Einsatz eines subkutanen Terbutalin-Infusatsystems zur Selbstapplikation der Bedarfsmedikation bei schwerer chronisch-obstruktiver Atemwegserkrankung (COPD).

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) may be difficult to stabilize with standard inhaled and oral medication. In those cases, outpatient care may even be impossible. Alternative therapeutic strategies, like subcutaneous self-application of terbutaline, could help to further improve health status. CASE REPORT: A 42-year old patient with severe COPD was admitted to the hospital. Despite maximal anti-obstructive therapy he required additional intravenous relief therapy and discharge was not possible. We treated this patient with a subcutaneous terbutaline pump for continuous and demand medication. We could show a significant decrease in additional intravenous medication, and the patient could leave the hospital. CONCLUSION: The use of terbutaline applied by a subcutaneous pump in addition to standard therapy may be helpful in severely ill patients suffering from COPD. This measure increased quality of life and shortened hospital stay.