Epithelial-mesenchymal transition (EMT) plays an important role in renal tubulointerstitial fibrosis and TGF-␤1 is

The present data demonstrate that high glucose increases cellular ROS in HPMC through activation of PKC, NADPH oxidase, and mitochondrial metabolism and that ROS, thus generated, up-regulate fibronectin expression by HPMC. ROS are not only downstream but also upstream signaling molecules to PKC and provide signal amplification in high glucose-induced fibronectin expression by HPMC. The present data imply that cellular ROS may be potential therapeutic targets in progressive accumulation of extracellular matrix in the peritoneal tissue of long-term peritoneal dialysis patients using high glucose-containing peritoneal dialysis solutions.

Progressive peritoneal fibrosis, membrane hyperpermeability, and ultrafiltration failure have been observed in patients on long-term peritoneal dialysis (PD). The present study tested the hypothesis that reactive oxygen species (ROS) generated by conventional PD solution (PDS) mediate functional and structural alterations of peritoneal membrane in vivo. Sprague-Dawley rats were randomized to control, PDS, PDS with an antioxidant, and PDS with an angiotensin II (Ang II) receptor blocker. Commercial PDS containing 3.86% glucose (20-30 ml) with or without N-acetylcystein (NAC) 10 mM or losartan 5 mg/kg was administered intraperitoneally twice a day for 12 weeks. Control rats received sham injection. Rats treated with PDS had significantly lower drain volume and D(4)/D(0) glucose, but higher D(4)/P(4) creatinine and increased membrane thickness and endothelial NOS (eNOS) expression compared to control rats. Omental transforming growth factor (TGF)-beta1, vascular endothelial growth factor (VEGF), collagen I, and heat-shock protein (hsp) 47 expression and lipid peroxide levels and dialysate VEGF and Ang II concentrations were significantly increased in rats treated with PDS compared to control. All of these changes were prevented by both NAC and losartan. In conclusion, the present study demonstrates that ROS generated by conventional PDS are, in large part, responsible for peritoneal fibrosis and membrane hyperpermeability. We suggest that antioxidants or Ang II receptor blockers may allow better preservation of the structural and functional integrity of the peritoneal membrane during long-term PD.

Introduction With the advent of genetically modified mice, it seems particularly advantageous to develop a mouse model of diabetic erectile dysfunction. Aim To establish a mouse model of type I diabetes by implementation of either multiple low-dose streptozotocin (STZ) protocol or single high-dose STZ protocol and to evaluate morphologic alterations in the cavernous tissue and subsequent derangements in penile hemodynamics in vivo. Methods Eight-week-old C57BL/6J mice were divided into three groups: a control group, a group administered the multiple low-dose STZ protocol (50 mg/kg × 5 days), and a group administered the single high-dose STZ protocol (200 mg/kg). Main Outcome Measures After 8 weeks, erectile function was measured by electrical stimulation of the cavernous nerve. The penis was then harvested and stained with hydroethidine (in situ analysis of superoxide anion), TUNEL, or antibodies to nitrotyrosine (marker of peroxynitrite formation), PECAM-1, smooth muscle α-actin, and phospho-eNOS. Penis specimens from a separate group of animals were used for phospho-eNOS and eNOS western blot or cGMP determination. Results Erectile function was significantly less in diabetic groups than in control group. The generation of superoxide anion and nitrotyrosine and the number of apoptotic cells in both cavernous endothelial and smooth muscle cells were significantly higher in diabetic groups than in control group. Cavernous tissue phospho-eNOS and cGMP expression and the number of endothelial and smooth muscle cells were lower in diabetic groups than in control group. Both diabetic models resulted in similar structural and functional derangements in the corpus cavernosum; however, the mortality rate was higher in mice receiving single high-dose of STZ than in those receiving multiple low-doses. Conclusion The mouse model of type I diabetes is useful and technically feasible for the study of the pathophysiologic mechanisms involved in diabetic erectile dysfunction.

OBJECTIVEPatients with diabetic erectile dysfunction often have severe endothelial dysfunction and respond poorly to oral phosphodiesterase-5 inhibitors. We examined the effectiveness of the potent angiopoietin-1 (Ang1) variant, cartilage oligomeric matrix protein (COMP)-Ang1, in promoting cavernous endothelial regeneration and restoring erectile function in diabetic animals.RESEARCH DESIGN AND METHODSFour groups of mice were used: controls; streptozotocin (STZ)-induced diabetic mice; STZ-induced diabetic mice treated with repeated intracavernous injections of PBS; and STZ-induced diabetic mice treated with COMP-Ang1 protein (days −3 and 0). Two and 4 weeks after treatment, we measured erectile function by electrical stimulation of the cavernous nerve. The penis was harvested for histologic examinations, Western blot analysis, and cGMP quantification. We also performed a vascular permeability test.RESULTSLocal delivery of the COMP-Ang1 protein significantly increased cavernous endothelial proliferation, endothelial nitric oxide (NO) synthase (NOS) phosphorylation, and cGMP expression compared with that in the untreated or PBS-treated STZ-induced diabetic group. The changes in the group that received COMP-Ang1 restored erectile function up to 4 weeks after treatment. Endothelial protective effects, such as marked decreases in the expression of p47phox and inducible NOS, in the generation of superoxide anion and nitrotyrosine, and in the number of apoptotic cells in the corpus cavernosum tissue, were noted in COMP-Ang1–treated STZ-induced diabetic mice. An intracavernous injection of COMP-Ang1 completely restored endothelial cell-cell junction proteins and decreased cavernous endothelial permeability. COMP-Ang1–induced promotion of cavernous angiogenesis and erectile function was abolished by the NOS inhibitor, N-nitro-L-arginine methyl ester, but not by the NADPH oxidase inhibitor, apocynin.CONCLUSIONSThese findings support the concept of cavernous endothelial regeneration by use of the recombinant Ang1 protein as a curative therapy for diabetic erectile dysfunction.

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Objectives: Human mesenchymal stem cells (MSCs) are efficacious in various cellular therapeutic applications and have been isolated from several tissues. Recent studies have reported that human tonsil tissue contains a new source of progenitor cells, potentially applicable for cell-based therapies. Information about the effects of donor age, long-term passage and cryopreservation are essential for clinical applications and cell-based therapies. Therefore, the authors investigated how the morphology, cell-surface markers, proliferation potential and differentiation capacity of tonsil-derived MSCs (T-MSCs) were affected by donor age, long-term passage, and cryopreservation. Materials and Methods: T-MSCs were isolated from tonsillar tissue of 20 patients undergoing tonsillectomy. Authors evaluated the effects of donor-age, long-term passage, and cryopreservation on the morphology, surface markers, proliferation potential and differentiation capacities of T-MSCs. Results: T-MSCs exhibited a fibroblast-like, spindle-shaped appearance. There were no significant morphological differences according to donor age, long-term passage or cryopreservation. T-MSCs isolated from donors of various ages were positive for markers CD90, CD44, and CD73, but negative for CD45, CD31, and HLA-DR. There were no significant differences in the expression of positive and negative surface markers as a function of donor age, long-term passage and cryopreservation. T-MSCs from different donor age groups showed similar proliferation potentials after passage 2. After long-term passage and cryopreservation, there were no significant morphological differences. Cryopreservation did not affect the proliferation potential of T-MSCs, but there was a significant decrease in the proliferation potential in long-term passage T-MSCs (passage 15). The effect of donor age, long-term passage and cryopreservation on the in vitro adipogenic, osteogenic, and chondrogenic differentiation potential of T-MSCs was not significant. Conclusion: The effect of donor age, long-term passage culture, and cryopreservation on T-MSC properties are negligible, except for the proliferation capacity of long-term cultured T-MSCs. Therefore, T-MSCs are considered to be promising MSCs that can be used as future alternative sources for autologous or allogenic MSCs.