Indices of methylation in sperm DNA from fertile men differ between distinct geographical regions.

STUDY QUESTION: Which are the main determinants, if any, of sperm DNA methylation levels? SUMMARY ANSWER: Geographical region resulted associated with the sperm methylation status assessed on genome-wide repetitive sequences. WHAT IS KNOWN ALREADY: DNA methylation level, assessed on repetitive sequences from peripheral blood lymphocyte, can vary with age, gender, alcohol consumption and white blood cell counts. STUDY DESIGN, SIZE, DURATION: A cross-sectional study. Individual data were collected from 269 young healthy men of proven fertility living in three geographical regions: Inuits from Greenland, Caucasians from Warsaw (Poland) and Kharkiv (Ukraine). Semen samples were collected between May 2002 and February 2004 and aliquots were immediately frozen. PARTICIPANTS/MATERIALS, SETTING, METHODS: We estimated sperm DNA global methylation level (DGML) in two ways. First DNA methylation in repetitive DNA sequences (LINE-1, Satα and Alu) was quantified by PCR pyrosequencing after bisulfite conversion and second by flow cytometry (FCM) using fluorescently labeled monoclonal antibodies anti-5-methylcytosine. We analyzed whether personal characteristics and habits, body mass index, semen quality parameters, sperm chromatin integrity, biomarkers of accessory gland function and the plasma concentration of reproductive hormones were associated with sperm DNA methylation levels in men. Associations were evaluated by analysis of variance and linear regression analyses. MAIN RESULTS AND THE ROLE OF CHANCE: The geographical location emerged as the main determinant when using the methylation level in repetitive sequences. FCM DGML results were not associated with those from repetitive sequence analysis. No other consistent associations between methylation markers and the assessed variables were identified across countries. LIMITATIONS, REASONS FOR CAUTION: The methods used are only surrogates of the actual sperm methylome and the methylation levels at individual specific loci were not explored. WIDER IMPLICATIONS OF THE FINDINGS: Sperm DGML is relatively independent from semen quality parameters and is a new candidate biomarker for epidemiological studies of the impact of environmental contaminants on male fertility. STUDY FUNDING/COMPETING INTERESTS: The study is part of the project CLEAR (Climate change, Environmental contaminants and Reproductive health) supported by the European Commission 7th framework program, contract no: FP7-ENV-2008-1-226217. No competing interest is declared.

Vorinostat synergises with capecitabine through upregulation of thymidine phosphorylase.

BACKGROUND: Potentiation of anticancer activity of capecitabine is required to improve its therapeutic index. In colorectal cancer (CRC) cells, we evaluated whether the histone deacetylase-inhibitor vorinostat may induce synergistic antitumour effects in combination with capecitabine by modulating the expression of thymidine phosphorylase (TP), a key enzyme in the conversion of capecitabine to 5-florouracil (5-FU), and thymidylate synthase (TS), the target of 5-FU. METHODS: Expression of TP and TS was measured by real-time PCR, western blotting and immunohistochemistry. Knockdown of TP was performed by specific small interfering RNA. Antitumour activity of vorinostat was assessed in vitro in combination with the capecitabine active metabolite deoxy-5-fluorouridine (5'-DFUR) according to the Chou and Talay method and by evaluating apoptosis as well as in xenografts-bearing nude mice in combination with capecitabine. RESULTS: Vorinostat induced both in vitro and in vivo upregulation of TP as well as downregulation of TS in cancer cells, but not in ex vivo treated peripheral blood lymphocytes. Combined treatment with vorinostat and 5'-DFUR resulted in a synergistic antiproliferative effect and increased apoptotic cell death in vitro. This latter effect was impaired in cells where TP was knocked. In vivo, vorinostat plus capecitabine potently inhibited tumour growth, increased apoptosis and prolonged survival compared with control or single-agent treatments. CONCLUSIONS: Overall, this study suggests that the combination of vorinostat and capecitabine is an innovative antitumour strategy and warrants further clinical evaluation for the treatment of CRC.

Fluid snacks to help persons with type 1 diabetes avoid late onset postexercise hypoglycemia.

PURPOSE: The present study assessed whether whole milk, skim milk, or two commercially available sports drinks are effective in preventing late onset postexercise hypoglycemia (LOPEH) in persons with type 1 diabetes mellitus. METHODS: Subjects ingested water, whole milk, skim milk, sport drink A (carbohydrate and electrolytes), or sport drink B (carbohydrate, fat, and protein) before, during, and after 1 h of bicycle exercise at 60% VO2max in the late afternoon. Drinks were isocaloric (470 +/- 150 kcal) and the number of calories consumed was based on individual energy expenditure. No adjustment in insulinization was allowed in anticipation of exercise. RESULTS: During water trials all subjects became hypoglycemic. Most drinks lead to a moderate hyperglycemia (range of mean values = 200-280 mg x dL(-1)) during the period between the end of exercise and dinner, but this was not the case for whole milk (range 80-120 mg x dL(-1)). Glycemia peaked about 1.5 h after dinner and declined over the next 90 min. Persistent hyperglycemia (range of means = 200-310 mg x dL(-1)) from after exercise to about 4 h postexercise was observed with sports drink B. A decline in glycemia in the evening was greatest during the skim milk trial and required subjects to ingest more carbohydrate as a late evening snack. The least decline during this period occurred during the whole milk trial. Subjects experienced pre-bed and early morning (0300 h) hypoglycemia in 7 of the 28 trials. CONCLUSIONS: These data show that whole milk and sports drinks that are designed for both quick (sport drink A) and long lasting (sport drink B) nutrient replenishment can be used by persons with type 1 diabetes in an effort to avoid LOPEH.