Serum vitamin D and colonic vitamin D receptor in inflammatory bowel disease.

AIM: To determine serum vitamin D levels and colonic vitamin D receptor (VDR) expression in inflammatory bowel disease (IBD) and non-IBD patients and correlate these with histopathology. METHODS: Puerto Rican IBD (n = 10) and non-IBD (n = 10) patients ≥ 21 years old scheduled for colonoscopy were recruited. Each patient completed a questionnaire and provided a serum sample and a colonic biopsy of normal-appearing mucosa. For IBD patients, an additional biopsy was collected from visually diseased mucosa. Serum vitamin D levels were measured by ultra-performance liquid chromatography and mass spectrometry. Hematoxylin and eosin stained tissue sections from colonic biopsies were classified histologically as normal or colitis (active/inactive), and scored for the degree of inflammation present (0-3, inactive/absent to severe). Tissue sections from colonic biopsies were also stained by immunohistochemistry for VDR, for which representative diagnostic areas were photographed and scored for staining intensity using a 4-point scale. RESULTS: The IBD cohort was significantly younger (40.40 ± 5.27, P < 0.05) than the non-IBD cohort (56.70 ± 1.64) with a higher prevalence of vitamin D deficiency (40% vs 20%, respectively) and insufficiency (70% vs 50%, respectively). Histologic inflammation was significantly higher in visually diseased mucosa from IBD patients (1.95 ± 0.25) than in normal-appearing mucosa from control patients (0.25 ± 0.08, P < 0.01) and from IBD patients (0.65 ± 0.36, P < 0.05) and correlated inversely with VDR expression in visually diseased colonic tissue from IBD patients (r = -0.44, P < 0.05) and from IBD patients with Crohn's disease (r = -0.69, P < 0.05), but not in normal-appearing colonic tissue from control patients or IBD patients. Control and IBD patient serum vitamin D levels correlated positively with VDR expression in normal colon from control and IBD patients (r = 0.38, P < 0.05) and with patient age (r = 0.54, P < 0.01). CONCLUSION: Levels of serum vitamin D correlate positively with colonic VDR expression in visually normal mucosa whereas inflammation correlates negatively with colonic VDR expression in visually diseased mucosa in Puerto Rican patients.

Effects of vitamin C on androgen receptor mediated actions in human prostate adenocarcinoma cell line LAPC-4.

OBJECTIVES: To examine the effects of vitamin C (VC) on androgen receptor (AR)-mediated functions in a human prostate cancer cell line, Los Angeles prostate cancer (LAPC-4). VC is an essential dietary substance in the maintenance and preservation of vital functions in humans. However, the role of VC in prostate cancer remains to be elucidated. METHODS: Cell proliferation and the expression of two well-known androgen regulated proteins, prostate-specific antigen and human glandular kallikrein-2, were studied in the presence of VC. RESULTS: In the presence of androgen and VC, both cell growth and the expression of prostate-specific antigen and human glandular kallikrein-2 proteins were decreased. Moreover, AR-mediated transcription activity of the prostate-specific antigen gene was suppressed with VC, similar to the phenomenon observed when cells were treated with hydrogen peroxide. These effects were reversed with catalase. However, additional studies did not reveal changes in the expression level of AR protein or its androgen-binding activity with the addition of VC. CONCLUSIONS: The results of our study suggest that the pro-oxidant property of VC might be one of the mechanisms by which it modulates AR-mediated function in LAPC-4 cells.