We have characterized the progressive stages of chronic intestinal inflammation that develops spontaneously in specific pathogen-free (SPF) mice with a targeted disruption in the IL-10 gene (IL-10 Ϫ / Ϫ ). Our longitudinal studies showed that inflammatory changes first appear in the cecum, ascending and transverse colon of 3-wk-old mutants. As the disease progressed, lesions appeared in the remainder of the colon and in the rectum. Some aged IL-10 Ϫ / Ϫ mice also developed inflammation in the small intestine. Prolonged disease with transmural lesions and a high incidence of colorectal adenocarcinomas (60%) was observed in 6-mo-old mutants. Mechanistic studies have associated uncontrolled cytokine production by activated macrophages and CD4

Summary Pharmacological ascorbate has been proposed as a potential anti-cancer agent when combined with radiation and chemotherapy. The anti-cancer effects of ascorbate are hypothesized to involve the autoxidation of ascorbate leading to increased steady-state levels of H2O2; however, the mechanism(s) for cancer cell-selective toxicity remain unknown. The current study shows that alterations in cancer cell mitochondrial oxidative metabolism resulting in increased levels of O2•− and H2O2 are capable of disrupting intracellular iron metabolism thereby selectively sensitizing non-small cell lung cancer (NSCLC) and glioblastoma (GBM) cells to ascorbate through pro-oxidant chemistry involving redox active labile iron and H2O2. In addition, preclinical studies and clinical trials demonstrate the feasibility, selective toxicity, tolerability, and potential efficacy of pharmacological ascorbate in GBM and NSCLC therapy.

Previous studies in vivo have shown that IL-10 infusion can prevent lethal endotoxic shock. Mice deficient in the production of IL-10 (IL1OT) were used to investigate the regulatory role of IL-10 in the responses to LPS in three experimental systems. In a model of acute endotoxic shock, it was found that the lethal dose of LPS for IL1OT mice was 20-fold lower than that for wild type (wt) mice suggesting that endogenous IL-10 determines the amount of LPS which can be tolerated without death. The high mortality rate of IL1OT mice challenged with modest doses of LPS was correlated to the uncontrolled production of TNF as treatment with anti-TNF antibody (Ab) resulted in 70% survival. Additional studies suggested that IL-10 mediates protection by controlling the early effectors of endotoxic shock (e.g., TNFa) and that it is incapable of directly antagonizing the production and/or actions of late appearing effector molecules (e.g., nitric oxide). We also found that ILAOT mice were extremely vulnerable to a generalized Shwartzman reaction where prior exposure to a small amount of LPS primes the host for a lethal response to a subsequent sublethal dose. The priming LPS dose for IL1OT mice was 100-fold lower than that required to prime wt mice implying that IL-10 is important for suppressing sensitization. In agreement with this assumption, IL-10 infusion was found to block the sensitization step. Interestingly, IL-10 was not the main effector of endotoxin tolerance as ILAOT mice could be tolerized to LPS. Furthermore, IL-10 infusion could not substitute for the desensitizing dose of LPS. These results show that IL-10 is a critical component of the host's natural defense against the development of pathologic responses to LPS although it is not responsible for LPS-induced tolerance. (J. Clin. Invest. 1995Invest. . 96:2339Invest. -2347

Background Treatment of pancreatic cancer with pharmacological ascorbate (ascorbic acid, vitamin C) decreases tumor progression in pre-clinical models. A phase I clinical trial was performed to establish safety and tolerability of pharmacological ascorbate combined with gemcitabine in patients with biopsy-proven stage IV pancreatic adenocarcinoma. Design Nine subjects received twice weekly intravenous ascorbate (15–125 g) employing Simon’s Accelerated Titration design to achieve a targeted post-infusion plasma level of ≥ 350 mg/dL (≥20 mM). Subjects received concurrent gemcitabine. Disease burden, weight, performance status, hematologic and metabolic labs, time to progression and overall survival were monitored. Results Mean plasma ascorbate trough levels were significantly higher than baseline (1.46 ± 0.02 vs. 0.78 ± 0.09 mg/dL, i.e. 83 vs. 44μM, p < 0.001). Adverse events attributable to the drug combination were rare and included diarrhea (n = 4) and dry mouth (n = 6). Dose-limiting criteria were not met for this study. Mean survival of subjects completing at least 2 cycles (8 weeks) of therapy was 13 ± 2 months. Conclusions Data suggest pharmacologic ascorbate administered concurrently with gemcitabine is well-tolerated. Initial data from this small sampling suggest some efficacy. Further studies powered to determine efficacy should be conducted.

-The purpose of this study was to characterize intestinal permeability changes over a range of physiologically relevant body temperatures in vivo and in vitro. Initially, FITC-dextran (4,000 Da), a large fluorescent molecule, was loaded into the small intestine of anesthetized rats. The rats were then maintained at ϳ37°C or heated over 90 min to a core body temperature of ϳ41, ϳ41.5, or ϳ42.5°C. Permeability was greater in the 42.5°C group compared with the 37, 41, or 41.5°C groups. Histological analysis revealed intestinal epithelial damage in heated groups. Everted intestinal sacs were then used to further characterize hyperthermia-induced intestinal permeability and to study the potential role of oxidative and nitrosative stress. Increased permeability to 4,000-Da FITC-dextran in both small intestinal and colonic sacs was observed at a temperature of 41.5-42°C compared with 37°C, along with widespread intestinal epithelial damage. Administration of antioxidant enzyme mimics or a nitric oxide synthase inhibitor did not reduce permeability due to heat stress, and tissue concentrations of a lipid peroxidation product were not altered by heat stress, suggesting that oxidative and nitrosative stress were not likely mediators of this phenomenon in vitro. In conclusion, hyperthermia produced increased permeability and marked intestinal epithelial damage both in vivo and in vitro, suggesting that thermal disruption of epithelial membranes contributes to the intestinal barrier dysfunction manifested with heat stress. intestine; heat stress; free radicals; nitric oxide; FITC-dextran