The February issue of the Journal of Lipid Research features a commentary by Ruth Prassl on a paper in which Yuhang Liu, et al. demonstrate a successful advanced method that allows for the quick freezing of low-density lipoprotein particles. Using this technique, Liu and colleagues were able to capture the intermediate state between isotropic and liquid crystalline.
The sample was examined by electron microscopy and 3-D reconstruction, and interestingly, the central density layer of LDL was perturbed, and its outer two layers were described by the authors as having a “disrupted shell”-shaped density. This paper’s findings, taken together with the existing two-state phase transition model, demonstrate the dynamic nature of lipid nucleation from isotropic to layered packing during the lipid core phase transition.
Another study of note is a paper looking at the feasibility of using the apolipoprotein A-I mimetic peptide L-4F as a potential therapeutic to increase high-density lipoprotein function in patients with coronary heart disease. Catherine E. Watson and colleagues performed two clinical trials, one in which patients were given a daily dose of intravenous L-4F for seven days and another in which L-4F was administered by subcutaneous injection daily for 28 days.
The peptide generally was well tolerated by both studies’ participants, but no improvement in HDL inflammatory index or paraoxonase was observed after single or multiple doses. Surprisingly, increases in two inflammatory markers, high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6), were observed following multiple doses of L-4F. Because the increase in hs-CRP was not dose-dependent, further study is needed to determine if L-4F is the sole culprit of the increase.
Mary L. Chang (email@example.com) is managing editor of the Journal of Lipid Research.