Impact of punicic acid and piceatannol on adipose tissue metabolism: insights from pig precision-cut adipose tissue slices and zebrafish models by Apolline Goudmaeker
Vendredi 22 mai 2026 à 17h00 - Salle Jean-Baptiste Carnoy (B.059) - Bâtiment Carnoy - Croix du Sud - 1348 Louvain-la-Neuve -
This thesis aimed to investigate the effects of dietary bioactive compounds, particularly polyunsaturated fatty acids (PUFA) and polyphenols, on lipid metabolism, inflammation, and adipose tissue regulation, using innovative in vivo and in vitro experimental models, including zebrafish and porcine precision-cut adipose tissue slices (PCATS).
In a first set of experiments, the ability of zebrafish to incorporate specific dietary PUFAs, including linoleic acid, α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, and punicic acid (PunA), a conjugated linolenic acid abundant in pomegranate seed oil (PSO), was evaluated. The results demonstrated efficient tissue incorporation of these fatty acids, with partial bioconversion of plant-derived PUFA into longer and more unsaturated fatty acids. Hepatic expression of inflammatory markers tended to be reduced in fish fed diets enriched with specific n-3 and conjugated PUFA compared with the sunflower oil diet rich in n-6 PUFAs. The detection of conjugated linoleic acids in tissues suggested the presence of Δ13-reductase activity in zebrafish.
Subsequently, the potential anti-obesogenic properties of PSO were explored in zebrafish. Complementary feeding trials showed that PSO limited body weight gain and BMI under overfeeding conditions, particularly when feed intake was accurately controlled through palatable dietary vectors, namely Artemia salina. However, when lipid accumulation was considered, overfeeding significantly increased whole-body lipid content in the PSO group, arguing against a protective effect on lipid storage. PunA was incorporated into tissues and partially converted into rumenic acid. These findings highlight the potential of PSO as a functional dietary ingredient for preventing obesity-related metabolic disturbances.
Finally, the effects of PunA and the polyphenol piceatannol (PIC) on lipolysis and adipokine regulation were assessed using porcine PCATS. PunA alone did not significantly affect lipolysis but showed trends toward modulating inflammatory and adipokine gene expression, whereas PIC exhibited an anti-lipolytic effect at high concentrations. Importantly, PIC was shown to interfere with enzymatic lipolysis assays in a dose-dependent manner, highlighting the necessity of validating lipolytic measurements with direct analyses such as gas chromatography. Combined treatments revealed distinct gene expression profiles, indicating potential interactions between these bioactive compounds in regulating adipose tissue metabolism. These results underscore the relevance of the PCATS model for mechanistic studies and emphasize the importance of considering both metabolic and inflammatory endpoints in evaluating dietary bioactive compounds.
Collectively, this work demonstrates the utility of zebrafish and porcine PCATS models for investigating the tissue incorporation, metabolism, and physiological effects of dietary PUFAs and polyphenols.
Jury members :
Prof. Cathy Debier (UCLouvain) (Promotrice)
Prof. Isabelle Donnay (UCLouvain) (Présidente)
Prof. Yvan Larondelle (UCLouvain) (Secrétaire)
Prof. Thierry Arnould (UNamur)
Prof. John Van Camp (UGent)
