Enhanced intestinal epithelial cell proliferation in diabetic rats correlates with ß-catenin accumulation.

The Wnt/ß-catenin signaling cascade is implicated in the control of stem cell activity, cell proliferation, and cell survival of the gastrointestinal epithelium. Recent evidence indicates that the Wnt/ß-catenin pathway is activated under diabetic conditions. The purpose of this study was to evaluate the role of Wnt/ß-catenin signaling during diabetes-induced enteropathy in a rat model. Male rats were divided into three groups: control rats received injections of vehicle; diabetic rats received injections of one dose of streptozotocin (STZ); and diabetic-insulin rats received injections of STZ and were treated with insulin given subcutaneously at a dose of 1 U/kg twice daily. Rats were killed on day 7. Wnt/ß-catenin-related genes and expression of proteins was determined using real-time PCR, western blotting, and immunohistochemistry. Among 13 genes identified by real-time PCR, seven genes were upregulated in diabetic rats compared with control animals including the target genes c-Myc and Tcf4. Diabetic rats also showed a significant increase in ß-catenin protein compared with control animals. Treatment of diabetic rats attenuated the stimulating effect of diabetes on intestinal cell proliferation and Wnt/ß-catenin signaling. In conclusion, enhanced intestinal epithelial cell proliferation in diabetic rats correlates with ß-catenin accumulation.

Effect of ozone on intestinal epithelial homeostasis in a rat model.

BACKGROUND: The positive effects of ozone therapy have been described in many gastrointestinal disorders. The mechanisms of this positive effect of ozone therapy are poorly understood. The purpose of the present study was to investigate whether the use of ozone may potentiate the gut intestinal mucosal homeostasis in a rat model. METHODS: Adult rats weighing 250-280 g were randomly assigned to one of three experimental groups of 8 rats each: 1) Control rats were given 2 mL of water by gavage and intraperitoneally (IP) for 5 days; 2) O3-PO rats were treated with 2 mL of ozone/oxygen mixture by gavage and 2 mL of water IP for 5 days; 3) O3-IP rats were treated with 2 mL of water by gavage and 2 mL of ozone/oxygen mixture IP for 5 days. Rats were sacrificed on day 6. Bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, and cell proliferation and apoptosis were evaluated following sacrifice. RESULTS: The group of O3-IP rats demonstrated a greater jejunal and ileal villus height and crypt depth, a greater enterocyte proliferation index in jejunum, and lower enterocyte apoptosis in ileum compared to control animals. Oral administration of the ozone/oxygen mixture resulted in a less significant effect on cell turnover. CONCLUSIONS: Treatment with an ozone/oxygen mixture stimulates intestinal cell turnover in a rat model. Intraperitoneal administration of ozone resulted in a more significant intestinal trophic effect than oral administration.

Phosphodiesterase-5 inhibition attenuates early renal ischemia-reperfusion-induced acute kidney injury: assessment by quantitative measurement of urinary NGAL and KIM-1.

Acute kidney injury (AKI) is a common clinical problem that still lacks effective treatment. Phosphodiesterase-5 (PDE5) inhibitors possess anti-apoptotic and anti-oxidant properties, making it a promising therapy for ischemia-reperfusion (I/R) injury of various organs. The present study evaluated the early nephroprotective effects of Tadalafil, a PDE5 inhibitor, in an experimental model of renal I/R. Sprague-Dawley rats were divided into two groups: vehicle-treated I/R (n = 10), and Tadalafil (10 mg/kg po)-treated I/R group (n = 11). After removal of the right kidney and collection of two baseline urine samples, the left renal artery was clamped for 45 min followed by reperfusion for 60, 120, 180, and 240 min. Functional and histological parameters of the kidneys from the various groups were determined. In the vehicle-treated I/R group, glomerular filtration rate was significantly reduced compared with that in normal kidneys. In addition, the ischemic kidney showed remarkable cast formation, necrosis, and congestion, a consistent pattern of acute tubular necrosis. Furthermore, urinary excretion of NGAL and KIM-1, two novel biomarkers of kidney injury, substantially increased following I/R insult. In contrast, Tadalafil treatment resulted in a significant improvement in kidney function and amelioration of the adverse histological alterations of the ischemic kidney. Noteworthy, the urinary excretion of NGAL and KIM-1 markedly decreased in the Tadalafil-treated I/R group. These findings demonstrate that Tadalafil possesses early nephroprotective effects in rat kidneys subjected to I/R insult. This approach may suggest a prophylactic therapy for patients with ischemic AKI.

Urinary NGAL and KIM-1: biomarkers for assessment of acute ischemic kidney injury following nephron sparing surgery.

PURPOSE: Nephron sparing surgery is considered the treatment of choice in most patients with confined renal cancer. Interrupting renal blood flow is often necessary during such surgery, which can induce significant renal injury. We explored the possibility of using urinary NGAL and KIM-1 excretion as novel biomarkers to assess the extent of acute kidney injury after nephron sparing surgery. MATERIALS AND METHODS: The study group included 27 patients who underwent open nephron sparing surgery for enhancing solid renal tumors. During surgery the renal artery was clamped for between 6 and 47 minutes. Urine samples were collected before surgery, and 1, 3, 8, 24, 48 and 72 hours after renal pedicle clamp removal. Urinary levels of NGAL and KIM-1 were determined. RESULTS: Renal artery clamping induced renal injury, as reflected by increased urinary NGAL and KIM-1 in all participants. These increases in urinary NGAL excretion were evident after 1 hour of renal ischemia and lasted for 72 hours. Urinary NGAL correlated with the serum creatinine increase and ischemia duration. Compared with patients without significantly increased serum creatinine, those with significantly increased serum creatinine after nephron sparing surgery had a greater increase in urinary NGAL but not in KIM-1. CONCLUSIONS: Renal injury severity after nephron sparing surgery could be quantitatively assessed by measuring urinary NGAL and KIM-1.