Esterified astaxanthin levels in lobster epithelia correlate with shell colour intensity: Potential role in crustacean shell colour formation

Carotenoids, particularly astaxanthin, are the primary pigment in crustacean shell colour. Sub-adults of the western rock lobster, Panulirus cygnus, moult from a deep red colour (termed the red phase) to a much paler colour (the white phase) at sexual maturation. We observe a 2.4-fold difference in the amount of total carotenoid present in the shell extracts of reds compared to whites, as might be expected. However, analysis of the underlying epithelium shows that there is no correlation with shell colour and the amount of free (unesterified) astaxanthin-the level of free astaxanthin in reds and whites is not significantly different. Instead, we observe a correlated two-fold difference in the amount of esterified astaxanthin present in the epithelium of red versus white individuals. These data suggest a role for esterified astaxanthin in regulating shell colour formation and suggest that esterification may promote secretion and eventual incorporation of unesterified astaxanthin into the exoskeleton. (c) 2005 Elsevier Inc. All rights reserved.

Inhibitors of cholesteryl ester transfer protein - a step forward in the treatment of coronary artery disease?

Although the LDL cholesterol-lowering statins have reduced the mortality and morbidity associated with coronary artery disease (CAD), considerable mortality and morbidity remains. Increasing HDL cholesterol levels is associated with reduced CAD mortality and morbidity. In healthy subjects with mild dyslipidemia, treatment with JTT-705 decreased cholesteryl ester transfer protein (CETP) activity, increased HDL cholesterol and decreased LDL cholesterol. Similarly, another CETP inhibitor, torcetrapib, has recently been shown to increase HDL cholesterol by 46%, decrease LDL cholesterol by 8% and have no effect on triglycerides in subjects with HDL cholesterol levels below 1.0 mmol/l. Increasing HDL cholesterol with inhibitors of CETP represents a new approach to dyslipidemia that requires further investigation, especially in patients with CAD.