Disequilibrium of polyunsaturated fatty acids status and its dual effect in modulating adipose tissue development and functions

Abstract

-White adipocytes are storing energy under the form of triglycerides whereas brown adipocytes dissipate energy from triglycerides by producing heat. In rodents and possibly in humans both types of fat cells participate in the total energy balance. From a quantitative view point, a positive energy balance (energy intake > energy expenditure) is commonly regarded as a major factor contributing to obesity. Recent studies demonstrate that by altering rates of adipocyte differentiation and proliferation, differences in fatty acid composition of dietary fats may also contribute to adipose tissue development, in particular with respect to the relative intake of ω6 to ω3 poly-unsaturated fatty acids (PUFAs). The ω6/ω3 ratio determines the availability of ω6-arachidonic acid (ARA) within adipose tissue and thus the level of various prostaglandins derived from the cyclooxygenase-mediated pathway. We had shown earlier that prostacyclin (Prostaglandin I2) stimulates fat cell differentiation and this effect could be reversed by ω3-PUFA supplementation. Moreover, we had assessed that under conditions of genome stability a Western-like fat diet rich in ω6-PUFA was sufficient to induce a gradual fat mass enhancement across generations. Recently, we have characterized a second effect of some ARA metabolites (prostaglandins E2 and F2α) which appear to inhibit the formation of brown adipocytes within white adipose tissue. Altogether, our results demonstrate that, in addition to favoring white adipose tissue formation, dietary excess of ω6-PUFA prevents the "browning" process to take place in white adipose tissue depots, and strongly suggest a favorable role of ω3-PUFA supplementation in preventing both processes.Keywords: White adipocyte / brite/brown adipocyte / arachidonic acid / prostaglandin / obesity Résumé -Double effet d'un déséquilibre du statut en acides gras polyinsaturés sur le développement et les fonctions du tissu adipeux. Les adipocytes blancs stockent l'énergie sous forme de triglycérides alors que les adipocytes bruns dissipent l'énergie issue de ces triglycérides en produisant de la chaleur. Chez les rongeurs, et certainement chez les humains, ces deux types d'adipocytes participent à l'équilibre énergétique global. D'un point de vue quantitatif, une balance énergétique positive (apports énergétiques > dépenses énergétiques) est généralement considérée comme un facteur important contribuant à l'obésité. Des études récentes démontrent que des différences de composition en acides gras des graisses alimentaires en particulier le ratio entre les acides gras polyinsaturés ω6 et ω3, contribuent au déve-loppement du tissu adipeux en altérant les niveaux de prolifération et de différenciation des adipocytes. Le ratio ω6/ω3 détermine la disponibilité de l'acide arachidonique ω6 (ARA) au sein du tissu adipeux et ainsi le niveau des différentes prostaglandines dérivées de la voie métabolique contrôlée par les cyclooxygénases. Nous avons précédemment montré que la prostacycline (Prostaglandin I2) stimule la différen...

Caracterización del aceite y harina obtenido de la semilla de uva silvestre (Vitis tiliifolia)

“…Among the polyunsaturated fatty acids, linoleic acid (Ω-6, 84.73%), followed by oleic acid (Ω-9, 5.83%) and gondoic acid (Ω-11, 0.03%) were found in the highest proportion. The linoleic acid content was close to that reported for seed oil Oecopetalum mexicanum (Hernández et al, 2013), however, for its use as an additive or dietary supplement it is necessary to consider that there must be a certain balance between fatty acids (Ω-6/(Ω-3) (Pisani et al, 2015). …”

“…El contenido de ácido linoleico fue cercano a lo reportado para aceite de semilla de Oecopetalum mexicanum (Hernández et al, 2013). Sin embargo, para su uso como aditivo o suplemento alimenticio es necesario considerar que debe haber un balance determinado entre ácidos grasos (Ω-6/(Ω-3) (Pisani et al, 2015).…”

The FTO Gene, Browning of Adipose Tissue and Omega-3 Fatty Acids

“…Over the years, Ailhaud et al [5], Massiera et al [6] and Pisani et al [8] have contributed enormously to understanding the role of arachidonic acid (AA) and its metabolites derived from the cyclooxygenase pathway in increasing WAT proliferation and decreasing browning of WAT. Under isoenergetic isolipidic conditions, inclusion of AA in the diet impaired brite adipocyte recruitment in the subcutaneous WAT compared to mice fed a standard diet [7].…”

“…AA is highly metabolized in WAT obtained from various sources, diet, or from LA metabolism in the liver or from phospholipids of preadipocytes and adipocytes via phospholipase A2 and from endocannabinoids via fatty acid amide hydrolase and monoacylglycerol lipase activities. High-fat diets rich in omega-6 fatty acids have been shown to increase the risk of leptin resistance, diabetes and obesity in humans and rodents [9,10], to lower mitochondrial activity and oxygen consumption, and to inhibit PPARγ target gene expression and mitochondrial uncoupling protein-1 (UCP1) gene expression [8]. …”

“…The inhibitory role of the omega-6 fatty acids (LA + AA) in the browning process of white fat cells has been precisely investigated. Prostaglandin E 2 (PGE2), a metabolite of AA derived from the cyclooxygenase pathway, favors the formation of energy-storing white adipocytes, and prostaglandin F 2α (PGF2a) prevents the formation of energy-dissipating brown-like adipocytes within WAT [8]. AA is highly metabolized in WAT obtained from various sources, diet, or from LA metabolism in the liver or from phospholipids of preadipocytes and adipocytes via phospholipase A2 and from endocannabinoids via fatty acid amide hydrolase and monoacylglycerol lipase activities.…”