Modulation of detoxification enzymes by watercress: in vitro and in vivo investigations in human peripheral blood cells.

BACKGROUND: Epidemiological studies indicate that consumption of cruciferous vegetables (CV) can reduce the risk of cancer. Supposed mechanisms are partly the inhibition of phase I and the induction of phase II enzymes. AIM: The aim of this study was to investigate in vitro and in vivo effects of watercress (WC), a member of the CV family, on chemopreventive parameters using human peripheral blood mononuclear cells (PBMC) as surrogate cells. We investigated the hypothesis that WC reduces cancer risk by inducing detoxification enzymes in a genotype-dependent manner. METHODS: In vitro gene expression and enzyme activity experiments used PBMC incubated with a crude extract from fresh watercress (WCE, 0.1-10 microL/mL with 8.2 g WC per 1 mL extract) or with one main key compound phenethyl isothiocyanate (PEITC, 1-10 microM). From an in vivo perspective, gene expression and glutathione S-transferase (GST) polymorphisms were determined in PBMC obtained from a human intervention study in which subjects consumed 85 g WC per day for 8 weeks. The influence of WC consumption on gene expression was determined for detoxification enzymes such as superoxide dismutase 2 (SOD2) and glutathione peroxidase 1 (GPX1), whilst the SOD and GPX activities in red blood cells were also analysed with respect to GST genotypes. RESULTS: In vitro exposure of PBMC to WCE or PEITC (24 h) increased gene expression for both detoxification enzymes GPX1 (5.5-fold, 1 microL/mL WCE, 3.7-fold 1 microM PEITC) and SOD2 (12.1-fold, 10 microL/mL WCE, 7.3-fold, 10 microM PEITC), and increased SOD2 activity (1.9-fold, 10 microL/mL WCE). The WC intervention had no significant effect on in vivo PBMC gene expression, as high individual variations were observed. However, a small but significant increase in GPX (p = 0.025) and SOD enzyme activity (p = 0.054) in red blood cells was observed in GSTM1*0, but not in GSTM1*1 individuals, whilst the GSTT1 genotype had no impact. CONCLUSION: The results indicate that WC is able to modulate the enzymes SOD and GPX in blood cells in vitro and in vivo, and suggest that the capacity of moderate intake of CV to induce detoxification is dependent in part on the GSTM1 genotype.

Clinically relevant differences between amelanotic malignant melanoma and granuloma pyogenicum.

Macroscopic discrimination between amelanotic malignant melanoma (aMM) and the so-called granuloma pyogenicum (GP) is often uncertain since reliable criteria for a clear differentiation of either growth are lacking. In a search of such criteria we analysed the data of 57 consecutive in-patients with cutaneous aMM and of 83 with GP presenting at our Department during the years 1970-1988. The following items were compared with each other: duration from growth onset to definite diagnosis, site of growth, age and sex of the patients. Significant differences (p less than 0.01) between either growth were found for all items evaluated. Our results substantiate the hitherto gained impression of a remarkably shorter median history of GP as compared to aMM (5 vs. 26 weeks). Furthermore, aMM prevailed in elder (age greater than 50 years) particularly female (70%) patients, whereas GP developed about equally in both sexes and at all ages. Site distribution was also found to differ for either growth (GP predominantly in the head and neck region, rarely on lower limbs; aMM in all areas, rarely on the trunk). These data yield additional measures for clinical distinction between aMM and GP.