N-Acetylcysteine and High-Dose Atorvastatin Reduce Oxidative Stress in an Ischemia-Reperfusion Model in the Rat Kidney.

OBJECTIVE: To investigate the effects of N-acetylcysteine (NAC) and high-dose atorvastatin (ATOR) in reducing oxidative stress in a rat kidney model of ischemia-reperfusion injury. METHODS: Forty female rats underwent clamping of the left renal artery for 30 minutes, followed by reperfusion. The effects of pre-ischemic administration of NAC and/or ATOR were evaluated within 4 groups: a) control (no NAC, no ATOR); b) NAC (intraperitoneal NAC administration); c) ATOR (oral ATOR administration); and d) NAC+ATOR (both drugs). Oxidative stress was assessed by measuring the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and myeloperoxidase (MPO). Post-ischemia-reperfusion injury was evaluated by means of renal histology. RESULTS: NAC, ATOR, and NAC+ATOR in rats showed lower MPO (P < .05) and higher GPx activity (P < .05) versus control; SOD activity was lower in NAC versus ATOR (P < .05). No difference among groups was found at histology. However, a lower rate of tubular ischemic lesions was evident in NAC+ATOR versus control (P = .07). CONCLUSIONS: Atorvastatin pretreatment provides protection against oxidative stress in a rat kidney model of ischemia-reperfusion injury, reinforcing the evidence of a beneficial effect of statins beyond their cholesterol-lowering properties.

High-fat feeding stimulates endocrine, glucose-dependent insulinotropic polypeptide (GIP)-expressing cell hyperplasia in the duodenum of Wistar rats.

AIMS/HYPOTHESIS: Incretins are hormones released by enteroendocrine cells in response to meals, depending upon absorption of nutrients. The present study aimed to elucidate the mechanisms through which a high-fat diet (HFD) induces insulin resistance and insulin hypersecretion by focusing on the effects on enteroendocrine cells, especially those secreting glucose-dependent insulinotropic polypeptide (GIP). METHODS: Forty male Wistar rats, 4 months old, were randomised into two groups; one group received a chow diet and the other one received a purified tripalmitin-based HFD ad libitum. An OGTT was performed every 10 days and histological and immunofluorescence evaluations of the duodenum were obtained at 60 days from the beginning of the diets. Plasma glucose, insulin, GIP and glucagon-like peptide-1 (GLP-1) levels were measured. Immunofluorescence analysis of duodenal sections for pancreatic duodenal homeobox-1 (PDX-1), KI67, GLP-1, GIP and insulin were performed. RESULTS: Compared with chow diet, HFD induced a progressive significant increase of the glucose, insulin and GIP responses to OGTT, whereas GLP-1 circulating levels were reduced over time. After 60 days of HFD, cellular agglomerates of KI67 and PDX-1 positive cells, negative for insulin and GLP-1 but positive for GIP staining, were found inside the duodenal mucosa, and apoptosis was significantly increased. CONCLUSIONS/INTERPRETATION: With the limitation that we could not establish a causal relationship between events, our study shows that HFD stimulates duodenal proliferation of endocrine cells differentiating towards K cells and oversecreting GIP. The progressive increment of GIP levels might represent the stimulus for insulin hypersecretion and insulin resistance.

High saturated-fat diet induces apoptosis in rat enterocytes and blunts GIP and insulin-secretive response to oral glucose load.

Lipoapoptosis has been described in many organs and tissues, but never in enterocytes. We hypothesized that a high saturated-fat diet can induce duodenal enterocyte apoptosis and impair gastric inhibitory polypeptide (GIP) secretion. Forty male Wistar rats, approximately 4 months old, were randomized on standard laboratory or purified tripalmitin-based high-fat diet (59% calories). An oral-glucose tolerance test was performed after 30 and 90 days of diet to measure plasma glucose, insulin and GIP. Duodena were processed for histology and immunohistochemistry by transferase-mediated dUTP nick end-labeling (TUNEL) method. Apoptosis was confirmed by enzyme-linked immunosorbent assay. Glycemic response was significantly higher (P < 0.01 vs controls) in rats after 90 days. Insulin curve was markedly increased at 30 days, while it was blunted at 90 days. GIP area under the curve was 425.6 +/- 67.6 ng ml(-1) at 30 days vs 150.2 +/- 33.4 ng ml(-1) in controls (P < 0.001) and dropped to 53.8 +/- 25.8 ng ml(-1) at 90 days (P < 0.0001). TUNEL-positive nuclei were 66.08+/-26.19 at 30 days 57 (34.58+/-17 in controls, P < 0.05) and 216.99 +/- 129.42 nuclei per mm(3) at 90 days (38.75 +/- 18.36 in controls, P < 0.0001). A high saturated-fat diet stimulates GIP secretion but with time induces apoptosis of duodenal villi epithelium, showing for the first time that enterocytes are also prone to lipoapoptosis. The reduction of circulating GIP levels might contribute to hypoinsulinemia and hyperglycemia.

Source of cell injected is a critical factors for short and long engraftment in xeno-transplantation.

This study aims to investigate engraftment of human cord blood and foetal bone marrow stem cells after in utero transplantation via the intracoelomic route in the sheep. Here, we performed transplantation in 14 single and 1 twin sheep foetuses at 40-47 days of development, using a novel schedule for injection. (i) Single injection of CD34(+) human cord blood stem cells via the coelomic route (from 10 to 50 x 10(4)) in seven single foetuses. (ii) Single injection of CD34(+) foetal bone marrow stem cells via the intracoelomic route with further numbers of cells (20 x 10(5) and 8 x 10(5), respectively) in three single and in one twin foetuses. (iii) Double fractioned injection (20-30 x 10(6)) via the coelomic route and 20 x 10(6) postnatally, intravenously, shortly after birth of CD3-depleted cord blood stem cells in four single foetuses. In the first group, three single foetuses showed human/sheep chimaerism at 1, 8 and 14 months after birth. In the second group, the twin foetuses showed human/sheep chimaerism at 1 month after birth. In the third group, only two out of four single foetuses that underwent transplantation showed chimaerism at 1 month. While foetal bone marrow stem cells showed good short-term engraftment (1 month after birth), cord blood stem cells were able to persist longer in the ovine recipients (at 1, 8 and 14 months after birth).