title: Carotenoids are decreased in biopsies from colorectal adenomas.
abstract: A lower intake of carotenoids is associated with an increased risk of colorectal cancer. In order to take advantage of the chemopreventive properties of carotenoids, it is necessary to determine carotenoid concentration at the target tissue. As early stages in the adenoma-carcinoma sequence of colorectal cancer might be susceptible to chemoprevention, we sought to determine carotenoid concentrations in biopsies from colorectal adenomas.
  
  
  METHODS
  Biopsies from colorectal adenomas and non-involved mucosa were taken from seven patients. For controls, biopsies were obtained from the ascending and descending colon of patients without polyps (n = 5). Concentration of carotenoids (alpha-, beta-carotene, lutein, lycopene, zeaxanthin, beta-cryptoxanthin) were determined by optimizing gradient HPLC-analysis. Results are expressed as pmol/microg DNA.
  
  
  RESULTS
  Except for alpha-carotene, all carotenoids could reliably be detected in all specimens. In control patients carotenoid concentrations were highest in the ascending colon, being followed by the descending colon and non-involved mucosa from polyp-carriers. In colorectal adenomas all carotenoids were significantly reduced as compared to-non-involved mucosa (beta-carotene: 0.37 vs 0.19, P<0.03; lycopene: 0.34 vs 0.21, P<0.06, beta-cryptoxanthin: 0.14 vs 0.09, P<0.03, zeaxanthin: 0.18 vs 0.09, P<0.02; lutein: 0.18 vs 0.13,P <0.02).
  
  
  CONCLUSIONS
  All carotenoids investigated are reduced in colorectal adenomas, suggesting that mucosal carotenoids could serve as biomarkers for predisposition to colorectal cancer. Moreover, anti-tumor activity exerted by carotenoids is limited due to mucosal depletion. We speculate that supplementation of a larger array of carotenoids might be beneficial for patients with colorectal adenoma.
authors.affiliation: Center of Internal Medicine, University of Hohenheim, Fruwirthstrasse 12, D-70593 Stuttgart, Germany
authors.forename: A
authors.initials: A
authors.lastname: Mühlhöfer
authors.forename: B
authors.initials: B
authors.lastname: Bühler-Ritter
authors.forename: J
authors.initials: J
authors.lastname: Frank
authors.forename: W G
authors.initials: WG
authors.lastname: Zoller
authors.forename: P
authors.initials: P
authors.lastname: Merkle
authors.forename: A
authors.initials: A
authors.lastname: Bosse
authors.forename: F
authors.initials: F
authors.lastname: Heinrich
authors.forename: H K
authors.initials: HK
authors.lastname: Biesalski
mesh_terms: D000236:Adenoma / Q000209:etiology* / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002338:Carotenoids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003106:Colon / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000209:etiology* / Q000473:pathology*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D018709:Statistics, Nonparametric
chemical_list: D002338:Carotenoids