In this issue

Insulin and β-agonists regulate adiponectin

Adiponectin is an adipocytokine produced and secreted by the fat cells (adipocytes). The regulation of adipokine homeostasis is implicated in the control of body weight, insulin sensitivity and metabolism, but little is known about the mechanisms that regulate adiponectin. In this study Li, Cong et al. show in rats that adiponectin secretion and expression are acutely regulated by the nutritional status and that insulin and β-adrenergic agonists act directly on adipocytes to regulate adiponectin levels; insulin was shown to increase the circulating adiponectin concentrations and mRNA levels, while the β-agonist BRL37344 decreased adiponectin concentrations. These findings may have clinical relevance to metabolic syndrome and diabetes.

Li, G., Cong, L. et al. Regulation of adiponectin secretion and expression by insulin and β-agonists in rat. Eur. J. Lipid Sci. Technol. 2013, 115, 136–141

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Dexketoprofen prodrug in lipid emulsion

The formulation and delivery system are important factors influencing the efficacy of drugs. In this study by Gao et al., the anti-inflammatory and anti-nociceptive activities of dexketoprofen are markedly improved by incorporating its prodrug, dexketoprofen isopropyl ester, into a lipid emulsion (the ester is more suitable for loading into an oil-in-water emulsion). The oil phase consisted of medium- and long-chain triacylglycerols, while egg yolk lecithin was used as emulsifier. The anti-inflammatory and anti-nociceptive effects of the o/w formulation were evaluated in rats and mice and compared with an aqueous injection solution.

Gao, R. et al. Improvement in the efficacy of dexketoprofen by its prodrug in lipid emulsion. Eur. J. Lipid Sci. Technol. 2013, 115, 153–160

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Novel fat substitutes?

The best-known calorie-free fat substitutes is probably olestra - octaesters of sucrose. Olestra cannot be hydrolyzed by human lipases and thus passes through the gastrointestinal tract undigested and does not contribute to the calorific intake. While olestra looks, feels and tastes like fat, it has some adverse effects. The paper by Lei et al. proposes novel candidate fat substitute 1,3-medium-chain acyl, 2-short-chain acetylglycerol that might have potential in combating the obesity problem. These compounds can be hydrolyzed by the pancreatic lipase, but the generated 2-monoacetin is expected to behave differently from 2-monoacylglycerol generated from natural TAG and eventually prevent efficient intestinal absorption of lipids (mechanism detailed in the paper). This concept needs to be tested in vivo.

Lei, Q., et al. Design and synthesis of 1,3-dicapryloyl-2-acetylglycerol as molecular probe for triacylglycerol metabolism study. Eur. J. Lipid Sci. Technol. 2013, 115, 232–238

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