Improved renal cancer prognosis among users of drugs targeting renin-angiotensin system

Cancer Causes & Control - We explored renal cell cancer (RCC) survival among users of antihypertensive medication as hypertension is proposed to be a risk factor for RCC and ACE-inhibitors and...     

A new biodegradable braided self-expandable PLGA prostatic stent: an experimental study in the rabbit

PURPOSE: The biodegradable PLGA (a copolymer of L-lactide and glycolide) urethral stent with a spiral configuration has been used clinically for the prevention of postoperative urinary retention after different types of thermal therapy for benign prostatic hyperplasia. A new braiding pattern for this stent has recently been developed by our group. The aim here was to investigate the in situ degradation and biocompatibility of the new braided stent in the rabbit urethra. MATERIALS AND METHODS: PLGA stents with a one-over-one braiding pattern and steel stents served as controls that were inserted into the posterior urethras of 24 male rabbits using a special delivery instrument. The animals were sacrificed after 1 week, 1 month, 2 months, or 4 months, and light microscopy and histologic analyses were performed. RESULTS: The delivery instrument worked well and cystoscopy was not needed in the insertion process. The braided PLGA stents degraded smoothly in 1 to 2 months. The metallic stents induced more epithelial hyperplasia and epithelial changes than the biodegradable stents at all time points analyzed. These differences increased during follow-up. CONCLUSION: The degradation process was well controlled and the biodegradable stents were more biocompatible than the metallic stents. The new stent can be inserted into the posterior urethra without cystoscopic aid.     

Drug-eluting bioabsorbable stents – An in vitro study

The aim of this study was to investigate the drug elution properties of novel drug-eluting bioabsorbable stents in vitro with four different drugs: dexamethasone, indomethacin, simvastatin and ciprofloxacin. Braided stents of poly-lactic acid (96l/4d) fibers were coated with a solution containing the appropriate bioabsorbable polymer and drug, with acetone as the solvent. Two different drug concentrations for both non-sterile and gamma sterilized stents were used for dexamethasone and indomethacin. For ciprofloxacin and simvastatin, only one drug dose was used. The stents were placed in sodium–phosphate-buffered saline in a shaking incubator (pH 7.4, +37 °C) and the eluted drug was measured periodically using an ultraviolet spectrometer. The drugs were hydrophobic to different degrees, as demonstrated by their various speeds of elution. In general, the higher the drug load in the stent, the faster the drug elution and the more hydrophilic the elution profile. In the cases of dexamethasone, indomethacin and ciprofloxacin, the sterilization decreased the drug elution rate slightly and the elution started earlier. However, in the case of ciprofloxacin, the gamma sterilization increased the drug elution rate slightly. Sustained elution was achieved for all four drugs. It was also evident that both the concentration and the hydrophility of the drug had a great influence on the drug elution profile. Gamma sterilization modified the drug elution profiles of dexamethasone, indomethacin and simvastatin, but had little effect on the drug elution profile of ciprofloxacin compared to three other drugs.     

Dexamethasone‐eluting Vascular Stents

Percutaneous transluminal angioplasty (PTA) with stenting is widely used in the treatment of vascular disorders, but restenosis remains a significant problem. Drug‐eluting stents (DES) have been developed as an attempt to reduce the intimal response leading to restenosis. Drugs used in DES include mainly immunosuppressive and anti‐proliferative compounds. Glucocorticoids are also an interesting possibility for those purposes because they have anti‐proliferative effects in vascular smooth muscle cells and down‐regulate the production of cytokines and growth factors driving inflammation and fibrosis. In this MiniReview, feasibility and safety of drug‐eluting metal and biodegradable vascular stents are discussed with special emphasis on dexamethasone‐eluting stents.