Abstract 4100: Nutrition and breast cancer prevention: adipose tissue proton magnetic resonance spectroscopy (1H-NMR) as biomarker of past dietary intake of lipids

Abstract

Abstract The prospect of a primary prevention of breast cancer by nutrition implies that population at risk is individualized. Previous identification of a composite indicator of the nutritional part (modifiable) of the risk of breast cancer in breast white adipose tissue theoretically offers this perspective (1), but the need for a biopsy and tedious biochemical analyses hampers this approach. 1H-NMR of adipose tissue lipids represents an attractive, non invasive approach, which could circumvent these limitations. The aim of the study was to determine whether 1H-NMR spectroscopy of adipose tissue may provide information on the nature of the diet received. We carried out a dietary intervention in rats with different enriched oils under isocaloric conditions, and examined spectra of the lipid extract of their adipose tissue according to diet. Two groups of Sprague-Dawley rats were fed a basal diet containing 7% of a mixture of peanut and rapeseed oils enriched with 8% of an oil without (palm oil) or with DHA (DHASCO, containing 40% docosahexaenoic acid, DHA). This DHA group was subdivided into 3 groups with low (1%), moderate (3%) or high (8%) DHASCO content. A third group (control diet) had a diet containing 15% of the mixture of peanut and rapeseed oils. All five groups (n=6 per group) received 15% lipids. At the end of the experiment (6 months), rats were sacrificed and mammary pad adipose tissue used for analysis of the lipid extract. 1H-NMR analysis was carried out on a Bruker DRX500 spectrometer operating at 11.7 T. Fatty acids were analyzed by gas chromatography. The fatty acid profile of adipose tissue differed among dietary groups. For example, expressed as peak area %, mean values for DHA ranged from undetectable (< 0.1%, , control or palm groups) to 0.7, 1.9, 5.9 % in the 3 DHA groups. Total monounsaturates (mainly oleic acid) were at 52.1% in the control group, 56.1% in the palm group, and 54.7, 52.3 and 48.9 %, respectively, for the 3 DHA groups. Total saturates (mainly palmitic and stearic acids) were 16.9 and 24.1 % in the control and palm groups, and 24.7, 26.3 and 26 % for the 3 DHA groups. Total n-6 PUFA (mainly linoleic acid) were at 26.3 in the control, 13.9 in the palm groups, and 15.5, 14.6, 14.2 % in the 3 DHA groups. Partial least squares (PLS) discriminant analysis was carried out on 1H-NMR spectra of the lipid extracts from adipose tissue. The integrated spectral regions showed separation between rat groups suggesting a different NMR lipid profile according to dietary interventions. The 1H-NMR spectroscopy approach used here was effective for identification of the impact of dietary interventions targeting lipids, and in turn, it could be tested for the evaluation of the lipid profile of human adipose tissues in relation with dietary habits. 1 - Bougnoux et al,. Diet, cancer and the lipidome. Cancer Epidemiol, Biomarkers & Prev 2006; 15(3):416-21. Citation Format: Lobna Ouldamer, Lydie Nadal-Desbarats, Stephan Chevalier, Caroline Goupille, Philippe Bougnoux. Nutrition and breast cancer prevention: adipose tissue proton magnetic resonance spectroscopy (1H-NMR) as biomarker of past dietary intake of lipids. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4100. doi:10.1158/1538-7445.AM2014-4100