Does coffee consumption alter plasma lipoprotein(a) concentrations? A systematic review

Coffee consumption alters plasma lipid and cholesterol concentrations, however, its effects on lipoprotein(a) (Lp(a)) have received little study. The aim of this PRISMA compliant systematic review was to examine the role of coffee on serum Lp(a).

This study was prospectively registered (PROSPERO 2015:CRD42015032335). PubMed, Scopus, Web of Science and Cochrane Central were searched from inception until 9th January 2016 to detect trials and epidemiological studies investigating the impact of coffee on serum Lp(a) concentrations in humans.

We identified six relevant publications describing nine experimental trials of various designs. There were a total of 640 participants across all studies and experimental groups. In short-term controlled studies, consumption of coffee, or coffee diterpenes was associated with either a reduction in serum Lp(a) of ≤11 mg/dL (6 trials, 275 participants), or no effect (2 trials, 56 participants). Conversely, one cross-sectional study with 309 participants showed serum Lp(a) was elevated in chronic consumers of boiled coffee who had a median Lp(a) of 13.0 mg/dL (range 0–130) compared with consumers of filtered coffee who had median Lp(a) 7.9 mg/dL (range 0–144).

The effect of coffee on Lp(a) is complex and may follow a biphasic time-course. The type of coffee and the method of preparation appear to be important to determining the effect on Lp(a).     

PEGylation Effects on the Interaction of Sphingomyelin Nanoemulsions with Serum Albumin: A Thermodynamic Investigation

The recent focus in the development of novel nanosystems for biomedical applications lays firmly on their interactions with biomolecules. Thermodynamic parameters driving the interaction between nanoparticles and proteins provide insights into complex processes at bio/nanointerface. The present work aims to investigate the binding mechanisms and the dominant contributions that determine the adsorption processes during the interactions of a model protein, that is, bovine serum albumin, with a new type of drug delivery systems, Vitamin E/sphingomyelin nanoemulsions, plain and coated with polyethylene glycol, and d -ɑ-tocopheryl polyethylene glycol succinate. The binding parameters (binding constant, binding stoichiometry, enthalpy, Gibbs energy, and entropy changes of binding) are evaluated by the isothermal titration calorimetry with a MicroCaliTC200 equipment. The effect of nanoemulsions on the protein stability is examined by measuring the thermodynamic parameters for the protein's unfolding (heat capacity; enthalpy, entropy, and free energy changes) with a NanoDSC (TA Instrument) apparatus. The thermodynamic profile shows for all compositions an entropy-driven interaction dominated by hydrophobic forces due to the rearrangements/displacement of the surrounding water molecules, while maintaining the native conformation of the protein. All the information acquired by thermodynamic approach may significantly enhance the knowledge with special focus on PEGylated nanoemulsions used for biomedical applications.