A Genetic Epidemiologic Study of Lipids and Depressive Symptoms

Abstract

In 1719, Hensing published the first monograph on the chemical composition of the brain, in which he isolated phosphorus from cerebral tissue. His work is considered a cornerstone of modern neurochemistryl. One century later, Vauquelin demonstrated that the phosphorus was actually bound to fat in the brain2. Meanwhile, cholesterol, a marker for all lipoproteins, was first discovered in bile and in gallstones by Poulletier de Ia Salle in 17693 and then rediscovered in 1815 by Chevreul, who named it"cholesterine"4.1n 1823, Chevreul's work resulted in his masterpiece on lipids" Recherches chimiques sur /es corps gras d'origine animate" where he described for the first time several fatty acids (margaric, oleic, stearic, butyric and caproic acids), including isovaleric acid (he named it"acide phocenique"), the first branched-chain fatty acid to be isolated from the head oil of dolphins and from porpoise oi15. Ten years later, in 1833, Boudet found cholesterol in blood6• Finally, in 1884, Johann Ludwig Wilhelm Thudichum published another fundamental work"A treatise on the chemical constitution of the brain'; in which he described the presence of sphinosine in brain, but also the presence of a choline and sphingosine containing phospholipid without glycerol, which he named sphingomyelin. He additionally described the presence of cerebrosides and sulfatides in brain extracts and isolated cephalin (phosphatidylethanolamine) as a phospholipid distinct from lecithin (phosphatidylcholine).