Catalpol protects against 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced cytotoxicity in osteoblastic MC3T3-E1 cells.

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a well-known environmental contaminant that produces a wide variety of adverse effects in humans. Catalpol, a major bioactive compound enriched in the dried root of Rehmannia glutinosa, is a major iridoid glycoside that alleviates bone loss. However, the detailed mechanisms underlying the effects of catalpol remain unclear. The present study evaluated the effects of catalpol on TCDD-induced cytotoxicity in osteoblastic MC3T3-E1 cells. Catalpol inhibited TCDD-induced reduction in cell viability and increases in apoptosis and autophagic activity in osteoblastic MC3T3-E1 cells. Additionally, pretreatment with catalpol significantly decreased the nitric oxide and nitrite levels compared with a control in TCDD-treated cells and significantly inhibited TCDD-induced increases in the levels of cytochrome P450 1A1 and extracellular signal-regulated kinase. Pretreatment with catalpol also effectively restored the expression of superoxide dismutase and extracellular signal-regulated kinase 1 and significantly enhanced the expression of glutathione peroxidase 4 and osteoblast differentiation markers, including alkaline phosphatase and osterix. Taken together, these findings demonstrate that catalpol has preventive effects against TCDD-induced damage in MC3T3-E1 osteoblastic cells.

Association of aryl hydrocarbon receptor transactivating activity, a potential biomarker for persistent organic pollutants, with the risk of gestational diabetes mellitus.

Persistent organic pollutants(POPs) are suggested to be potential risk factors for gestational diabetes mellitus(GDM). We examined the hypothesis that the aryl hydrocarbon receptor trans-activating(AhRT) activity, a potential biomarker for the presence of POPs, could be a GDM risk factor in pregnant women. A total of 390 GDM and 100 normal pregnant(non-GDM) subjects in the Korea National Diabetes Program cohort voluntarily participated. We measured AhRT activity and concentrations of ATP and reactive oxygen in the serum collected at the screening of the participants for GDM using recombinant Hepa1c1c7 cells. Odds ratios(ORs) and 95% confidence intervals(CIs) were estimated using multivariable logistic regression models. The sensitivity and specificity of AhRT activity for GDM diagnostics were measured by receiver operating characteristic(ROC) analysis. Body mass index at pre-pregnancy and delivery and systolic blood pressure were significantly higher in the GDM group. AhRT activity was higher, and ATP concentrations were lower in the GDM group than the non-GDM group(P < 0.0001). AhRT activity was significantly higher in the GDM group(OR 29.3, 95% CI 10.9-79.1) compared with non-GDM(P < 0.0001). Serum glucose concentration at 1 h after a 50 g glucose challenge(glucose-50) was moderately correlated with AhRT activity(r2 = 0.387) and negatively correlated with ATP production(r2 = -0.650). In the ROC curve, AhRT activity had 70.9% sensitivity and 90.0% specificity for glucose-50, a GDM screening method. In conclusion, this study suggests that serum AhRT activity is positively associated with the risk of GDM.

Orientin reduces the inhibitory effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on adipogenic differentiation and insulin signaling pathway in murine 3T3-L1 adipocytes.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) accumulates in human body, probably influencing adipocyte differentiation and causing various toxic effects, including wasting syndrome. Recently, orientin, a phenolic compound abundant in natural health products, has been shown to have antioxidant properties. We investigated the protective effects of orientin against TCDD-induced adipocyte dysfunction and its underlying mechanisms. In this study, orientin suppressed TCDD-induced loss of lipid accumulation. Orientin inhibited TCDD-driven decreases in the levels of peroxisome proliferator-activated receptor γ and adiponectin. Orientin also reduced TCDD-induced prostaglandin E2, and cytosolic phospholipase A2α levels, and increased TCDD-inhibited peroxisome proliferator-activated receptor gamma coactivator 1-alpha levels in 3T3-L1 adipocytes. TCDD reduced the levels of insulin receptor substrate 1 and glucose transporter 4, and decreased insulin-stimulated glucose uptake activity; however, orientin diminished these TCDD-induced effects. These results suggest that orientin may have beneficial effects on the prevention of TCDD-induced wasting syndrome and type II diabetes mellitus accompanied by insulin resistance.

Smoking and atherosclerotic cardiovascular disease in women with lower levels of serum cholesterol.

This cohort study of Koreans examines the relationship between smoking on atherosclerotic cardiovascular disease (ASCVD) and whether serum levels of total cholesterol modify the impact of smoking on ASCVD. A 10-year prospective cohort study was carried out on 234,399 Korean women, ranging 40-69 years of age who received health insurance from the National Health Insurance Corporation and had a medical evaluation in 1993. The main outcome measures were hospital admissions and deaths from ischemic heart disease (IHD), cerebrovascular disease (CVD), and total ASCVD. At baseline, 13,696 (5.8%) were current smokers and 105,755 (45.1%) had a total cholesterol <200mg/dl. Between 1994 and 2003, 4534 IHD (176/100,000 person year), 7961 CVD (310/100,000 person year), and 2418 other ASCVD events (94/100,000 person year) occurred. In multivariate Cox proportional hazard models controlling for age, hypertension, hypercholesterolemia, diabetes and alcohol drinking, current smoking increased the risk of IHD [hazard ratio (HR)=1.7 (95% CI: 1.5-1.9)], CVD [HR=1.6 (95% CI: 1.5-1.6)], and total ASCVD events [HR=1.6 (95% CI: 1.5-1.7)]. Throughout the range of serum cholesterol levels, current smoking significantly increased the risk of myocardial infarction and CVD, but not angina pectoris. There was no evidence of an interaction between smoking and serum cholesterol (p for interaction=0.469, 0.612, and 0.905 for IHD, CVD, and total ASCVD, respectively). This study demonstrated that smoking was a major independent risk factor for IHD, CVD and ASCVD in Korean women. A low cholesterol level confers no protective benefit against smoking-related ASCVD.