A Presurgical Study of Curcumin Combined with Anthocyanin Supplements in Patients with Colorectal Adenomatous Polyps

Abstract

Adenomatous polyps are precancerous lesions associated with a higher risk of colorectal cancer (CRC). Curcumin and anthocyanins have shown promising CRC-preventive activity in preclinical and epidemiological studies. The objective of this window-of-opportunity, proof-of principle trial was to evaluate the effect of curcumin combined with anthocyanin supplements on tissue biomarkers of colorectal adenomatous polyps. Eligible patients received either anthocyanin and curcumin supplementation or related matching placebo for 4-6 weeks before polyp removal. Adenomatous polyps and adjacent tissue biopsies were collected at baseline and after supplementation for immunohistochemical assessment of β-catenin, NF-kappa B (NF-κB), Ki-67, P53, and dysplasia. No differences were observed in baseline biomarker expression between normal and dysplastic tissues. The combination of anthocyanins and curcumin resulted in a significant borderline reduction of NF-κB immunohistochemistry (IHC) expression in adenoma tissue (geometric mean ratio (GMR): 0.72; 95% confidence interval (CI): 0.51-1.00; p-value: 0.05) and a trend to a reduction of Ki-67 (GMR: 0.73; 95% CI: 0.50-1.08; p-value: 0.11). No significant modulation of biomarkers in normal adjacent mucosa was observed. We concluded that the combined supplementation of anthocyanins and curcumin seems to lead to a potentially favorable modulation of tissue biomarkers of inflammation and proliferation in colon adenomas.

Keywords: Ki-67 antigen; NF-kappa B; adenomatous polyps; anthocyanins; curcumin; dietary supplement; prevention.

Figure 1

CONSORT flow diagram of the phases of the MiRACol randomized trial of the active and placebo group as well as the number of patients included in the analysis.

Figure 2

Analysis of plasma curcuminoids in samples collected at baseline and on two occasions on the final day of the study, immediately prior to the last dose and 1 h post-dose. Only a subset of patients were selected at random for LC-MS/MS analysis. (A) Structures of curcumin, demethoxycurcumin, and the mono-conjugated sulfate and glucuronide metabolites analyzed in the samples. (B) Plasma concentrations of the total curcuminoids in each patient at the three time points. Solid lines correspond to the patients in the active arm (n = 8), and the dashed lines indicate the patients in the placebo arm (n = 7). (C) The profile of curcumin species detected in the patients in the active arm 1 h post-dose. Values shown are the mean (±SEM) contribution of each curcumin species detected to the total quantifiable curcuminoids for the 8 patients. The profile was similar in samples collected immediately prior to the last dose (not shown).

Figure 3

The effect of treatment on tissue biomarkers is assessed as a GMR. GMR is obtained from a generalized linear model with the log-transformed value of each marker with outcome and treatment (active vs. placebo) as the predictors. Each model is adjusted for the log-transformed baseline value of the marker, age, and sex. Other possible covariates (see Table 1) are inserted, if they involve a change greater than 5% on the GMR related to the effect of treatment. Abbreviations: Ki-67, protein encoded by the MKI67 gene; P53, protein encoded by the TP53 gene; NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells; β-catenin, protein encoded by the CTNNB1 gene; GMR, geometric mean ratio; CI, confidence interval.

Figure 4

Immunohistochemistry (IHC) assessment of Ki-67 in high-grade dysplasia showing positive staining in 100% of cells in the pre-treatment sample (A) and 80% of cells post-treatment (B) (magnification: 10× and 40× in the box). Panels A and B are representative of the pre- and post-treatments from the same patient.

Figure 5

Immunohistochemical assessment of NF-κB-p65 protein in high-grade dysplasia showing positive cytoplasmic staining in 80% of cells in pre-treatment tissue sample (A) and 60% of cells in post-treatment samples (B) (magnification: 10× and 40× in the box). Panels A and B are representative of the pre- and post-treatments from the same patient.