Sodium selenite ameliorates dextran sulfate sodium-induced chronic colitis in mice by decreasing Th1, Th17, and γδT and increasing CD4(+)CD25(+) regulatory T-cell responses.

AIM: To assess the effect of sodium selenite on the severity of dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice. METHODS: Mice were randomly divided into four groups (n = 10/group): normal group, selenium (Se) group, chronic colitis group, and Se + chronic colitis group. The mice were sacrificed on day 26. Survival rates, clinical symptoms, colon length, and histological changes were determined. The percentages and absolute numbers of immune system cells in the lamina propria lymphocytes (LPL) of the colon, the expression of mRNA in colon tissue, and the concentrations of Th1, Th17, and Treg cytokines in LPL from the large intestine, were measured. RESULTS: Se significantly ameliorated the symptoms of colitis and histological injury (P < 0.05 each), increasing the proportions of neutrophils and CD4+ CD25+ T cells (P < 0.05 each) and decreasing the proportions of γδT cells, CD4+, CD4+CD44+, and CD4+ CD69+ T cells in LPL (P < 0.05 each). Moreover, Se reduced the expression of IL-6, IFN-γ, IL-17A, IL-21, T-bet, and RORγt (P < 0.05 each), but enhanced the expression of IL-10 and Foxp3 (P < 0.05 each). CONCLUSION: These results suggest that Se protects against DSS-induced chronic colitis perhaps by increasing the number of CD4(+)CD25(+) Tregs that suppress the secretion of proinflammatory cytokines and populations of Th1, Th17, and γδT cells.

Smoking and air pollution exposure and lung cancer mortality in Zhaoyuan County.

BACKGROUND: Simultaneous exposure to high levels of air pollution and high tobacco consumption at the same place is rare. The aim of the present study was to evaluate the impact of the two factors on the risk of developing lung cancer. METHODS: Data on the number of deaths due to lung cancer and on population from 1970 to 2009 were obtained from Zhaoyuan County. Data on the smoking populations were obtained at random sampling survey during the time in Zhaoyuan. Data on the components of atmospheric surveillance were obtained from the local environmental protection offices. Logarithmic linear regression and general log-linear Poisson age-period-cohort (APC) models were used to estimate age, period, cohort, gender, smoking, and air pollution effects on the risk of lung cancer mortality. RESULTS: The standardized mortality rates of lung cancer drastically increased from 8.43 in per 100 000 individuals in the 1970-1974 to 25.67 in per 100 000 individuals in the 2005-2009 death survey. The annual change of lung cancer mortality was 3.20%. In the log linear regression model, the age, proportion of smokers, gender, period, and air pollution are significantly associated with lung cancer mortality. The APC analysis shows that the relative risks (RRs) of gender, smoking, and air pollution are 2.29 (95% confidence interval (CI): 2.16-2.43), 3.05 (95% CI = 2.76-3.36), and 1.42 (95% CI = 1.19-1.69), respectively. Compared with the period 1970-1974, high RRs were found during 1995-2009. Compared with the birth cohort 1950-1954, the RRs increased in the birth cohorts of 1910 to the 1940. Compared the aged 35-59 and 60-84 in the 1980-1984 death survey (not exposed to air pollution) with that in the 2005-2009 death survey (exposed to air pollution), The two age groups exposed to air pollution, 25 years later, had an increased mortality rates for lung cancer by 2.27 and 3.55 times for males and by 1.47 and 3.35 times for females. CONCLUSION: The mortality rates of lung cancer drastically increased in the past 35 years. The trend of lung cancer mortality may be in a great extent possibly due to the effects of combined smoking and air pollution exposure.

Nutrition deficiency increases the risk of stomach cancer mortality.

BACKGROUND: The purpose of the study is to determine whether exposure to malnutrition during early life is associated with increased risk of stomach cancer in later life. METHODS: The design protocol included analyzing the trend of gastric cancer mortality and nutrition and evaluating the association between nutrient deficiency in early life and the risk of gastric cancer by hierarchical age-period-birth cohort (APC) analysis using general log-linear Poisson models and to compare the difference between birth cohorts who were exposed to the 1959-1961 Chinese famine and those who were not exposed to the famine. Data on stomach cancer mortality from 1970 to 2009 and the dietary patterns from 1955 to 1985 which included the 1959-1961 Chinese famine period in the Zhaoyuan County population were obtained. The nutrition information was collected 15 years prior to the mortality data as based on the latest reference of disease incubation. RESULTS: APC analysis revealed that severe nutrition deficiency during early life may increase the risk of stomach cancer. Compared with the 1960-1964 birth cohort, the risk for stomach cancer in all birth cohorts from 1900 to 1959 significantly increased; compared with the 1970-1974 cohort, the risk for stomach cancer in the 1975-1979 cohort significantly increased, whereas the others had a steadily decreased risk; compared with 85-89 age group in the 2005-2009 death survey, the ORs decreased with younger age and reached significant levels for the 50-54 age group after adjusting the confounding factors. The 1930 to 1964 group (exposed to famine) had a higher mortality rate than the 1965 to 1999 group (not exposed to famine). For males, the relative risk (RR) was 2.39 and the 95% confidence interval (CI) was 1.51 to 3.77. For females, RR was 1.64 and 95% CI was 1.02 to 2.62. CONCLUSION: The results of the present study suggested that prolonged malnutrition during early life may increase the risk of stomach cancer mortality in later life.