Search

BACKGROUND: L-Theanine (LTA) is a biologically active ingredient in tea that shows great potential for regulating lipid metabolism. Bile acids (BA), an important end-product of cholesterol catabolism, participate in the regulation of lipid metabolism and gut microbiota. Here, we investigated the effect of LTA on lipid metabolism and the mechanism by which it regulates BA metabolism and gut microbiota. Male BALB/c mice were treated with LTA for 28 days. RESULTS: Daily LTA doses of 100 and 300 mg kg-1 d-1 altered the gut microbiota in mice, predominantly by decreasing Lactobacillus, Streptococcus, Bacteroides, Clostridium and Enterorhabdus microbes associated with bile-salt hydrolase (BSH) activity, thereby decreasing the activity of BSH and increasing the levels of ileum conjugated BA (such as glycocholic acid (GCA) and lithocholic acid), thereby inhibiting the intestinal farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) signaling pathway. Inhibition of FXR-FGF15 signaling was accompanied by upregulation of cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and increased hepatic production of cholic acid, deoxycholic acid, GCA, glycine cholic acid and glycine ursodeoxycholic acid. Meanwhile, increasing hepatic unconjugated BA upregulated the mRNA and protein expression of liver 3-hydroxy-3-methylglutaryl-CoA reductase and downregulated the mRNA and protein expression of stearoyl-CoA desaturase-1, liver low-density lipoprotein receptor and type B scavenger receptor. Therefore, the serum levels of cholesterol and triglycerides decreased. CONCLUSION: Our findings indicate that LTA regulates lipid metabolism by modulating the gut microbiota and BA metabolism via the FXR-FGF15-CYP7A1 pathway. [ABSTRACT FROM AUTHOR]

Shi G, Ye D-W, Yao X, Zhang S, Dai B, Zhang H, Shen Y, Zhu Y, Zhu Y, Xiao W, Ma C. Extramammary Paget’s diseases in men from the Shanghai area: its association with PSA level increase. APMIS 2010; 118: 777–81. The aim of this study was to determine the incidence of prostate cancer in patients with extramammary Paget’s disease (EMPD). All cases of EMPD diagnosed between 1992 and 2007 in Shanghai Cancer Hospital were collected and analyzed for the incidence of prostate cancer. The median follow-up was 78 months. In total, 38 cases of invasive and 10 cases of in situ EMPD had been registered. A second malignancy was found in 28.9% (11/38) of patients with invasive EMPD and in 30% (3/10) of patients with in situ EMPD. Patients had an increased risk of developing a second cancer compared with the general population (standardized incidence ratio: 1.7; 95% confidence interval 1.2–2.4). Sixteen patients had serum prostate-specific antigen (PSA) level above 4 ng/mL; five developed prostate cancer, three of them with PSA levels beyond 100 ng/mL. The incidence of prostate cancer is 10.4% in this patient group. Patients with EMPD were more likely to have prostate cancer than the general population. Although the prognosis of EMPD is fairly good, a thorough search for a second tumor is recommended. [ABSTRACT FROM AUTHOR]