Hepatic accumulation of intestinal cholesterol is decreased and fecal cholesterol excretion is increased in mice fed a high-fat diet supplemented with milk phospholipids

<p>Abstract</p> <p>Background</p> <p>Milk phospholipids (PLs) reduce liver lipid levels when given as a dietary supplement to mice fed a high-fat diet. We have speculated that this might be due to reduced intestinal cholesterol uptake.</p> <p>Methods</p> <p>Mice were given a high-fat diet for 3 or 5 weeks that had no added PL or that were supplemented with 1.2% by wt PL from cow's milk. Two milk PL preparations were investigated: a) a PL-rich dairy milk extract (PLRDME), and b) a commercially-available milk PL concentrate (PC-700). Intestinal cholesterol uptake was assessed by measuring fecal and hepatic radioactivity after intragastric administration of [¹⁴C]cholesterol and [³H]sitostanol. Fecal and hepatic lipids were measured enzymatically and by ESI-MS/MS.</p> <p>Results</p> <p>Both PL preparations led to significant decreases in total liver cholesterol and triglyceride (-20% to -60%, <it>P </it>< 0.05). Hepatic accumulation of intragastrically-administered [¹⁴C]cholesterol was significantly less (-30% to -60%, <it>P </it>< 0.05) and fecal excretion of [¹⁴C]cholesterol and unlabeled cholesterol was significantly higher in PL-supplemented mice (+15% to +30%, <it>P </it>< 0.05). Liver cholesterol and triglyceride levels were positively correlated with hepatic accumulation of intragastrically-administered [¹⁴C]cholesterol (<it>P </it>< 0.001) and negatively correlated with fecal excretion of [¹⁴C]cholesterol (<it>P </it>< 0.05). Increased PL and ceramide levels in the diet of mice supplemented with milk PL were associated with significantly higher levels of fecal PL and ceramide excretion, but reduced levels of hepatic PL and ceramide, specifically, phosphatidylcholine (-21%, <it>P </it>< 0.05) and monohexosylceramide (-33%, <it>P </it>< 0.01).</p> <p>Conclusion</p> <p>These results indicate that milk PL extracts reduce hepatic accumulation of intestinal cholesterol and increase fecal cholesterol excretion when given to mice fed a high-fat diet.</p

Dietary Phospholipids and Intestinal Cholesterol Absorption

Experiments carried out with cultured cells and in experimental animals have consistently shown that phospholipids (PLs) can inhibit intestinal cholesterol absorption. Limited evidence from clinical studies suggests that dietary PL supplementation has a similar effect in man. A number of biological mechanisms have been proposed in order to explain how PL in the gut lumen is able to affect cholesterol uptake by the gut mucosa. Further research is however required to establish whether the ability of PLs to inhibit cholesterol absorption is of therapeutic benefit

Dietary milk phospholipids and their effects on cardiovascular risk factors / Chi Ling Elaine Wat.

Cardiovascular disease is responsible for a significant portion of morbidity and mortality in Australia. The metabolic syndrome, which is the clustering of cardiometabolic risk factors, is well known to be associated with increased risk of CVD. There is thus great interest in treating and preventing this metabolic disease. Pharmaceutical approaches to the treatment of the metabolic syndrome to this date have been inadequate. Increasing evidence suggests that dietary PLs may be potentially cardioprotective. The aim of this thesis is therefore to investigate the possibility that PLs can be extracted from dairy milk, and to identify and characterise the potent ability of dairy milk PLs to be used to treat and/or prevent CVD

Enhanced Transdermal Permeability via Constructing the Porous Structure of Poloxamer-Based Hydrogel

A major concern for transdermal drug delivery systems is the low bioavailability of targeted drugs primarily caused by the skin’s barrier function. The resistance to the carrier matrix for the diffusion and transport of drugs, however, is routinely ignored. This study reports a promising and attractive approach to reducing the resistance to drug transport in the carrier matrix, to enhance drug permeability and bioavailability via enhanced concentration-gradient of the driving force for transdermal purposes. This approach simply optimizes and reconstructs the porous channel structure of the carrier matrix, namely, poloxamer 407 (P407)-based hydrogel matrix blended with carboxymethyl cellulose sodium (CMCs). Addition of CMCs was found to distinctly improve the porous structure of the P407 matrix. The pore size approximated to normal distribution as CMCs were added and the fraction of pore number was increased by over tenfold. Transdermal studies showed that P407/CMCs saw a significant increase in drug permeability across the skin. This suggests that P407/CMC with improved porous structure exhibits a feasible and promising way for the development of transdermal therapy with high permeability and bioavailability, thereby avoiding or reducing use of any chemical enhancers

Nanoparticle-Encapsulated Chlorhexidine against Oral Bacterial Biofilms

<div><p>Background</p><p>Chlorhexidine (CHX) is a widely used antimicrobial agent in dentistry. Herein, we report the synthesis of a novel mesoporous silica nanoparticle-encapsulated pure CHX (Nano-CHX), and its mechanical profile and antimicrobial properties against oral biofilms.</p><p>Methodology/Principal Findings</p><p>The release of CHX from the Nano-CHX was characterized by UV/visible absorption spectroscopy. The antimicrobial properties of Nano-CHX were evaluated in both planktonic and biofilm modes of representative oral pathogenic bacteria. The Nano-CHX demonstrated potent antibacterial effects on planktonic bacteria and mono-species biofilms at the concentrations of 50–200 µg/mL against <i>Streptococcus mutans</i>, <i>Streptococcus sobrinus</i>, <i>Fusobacterium nucleatum</i>, <i>Aggregatibacter actinomycetemcomitans</i> and <i>Enterococccus faecalis</i>. Moreover, Nano-CHX effectively suppressed multi-species biofilms such as <i>S. mutans, F. nucleatum</i>, <i>A. actinomycetemcomitans</i> and <i>Porphyromonas gingivalis</i> up to 72 h.</p><p>Conclusions/Significance</p><p>This pioneering study demonstrates the potent antibacterial effects of the Nano-CHX on oral biofilms, and it may be developed as a novel and promising anti-biofilm agent for clinical use.</p></div

Evaluation of a topical herbal agent for the promotion of bone healing

A topically used Chinese herbal paste, namely, CDNR, was designed to facilitate fracture healing which is usually not addressed in general hospital care. From our in vitro studies, CDNR significantly inhibited the release of nitric oxide from RAW264.7 cells by 51 to 77%. This indicated its anti-inflammatory effect. CDNR also promoted the growth of bone cells by stimulating the proliferation of UMR106 cells up to 18%. It also increased the biomechanical strength of the healing bone in a drill-hole defect rat model by 16.5% significantly. This result revealed its in vivo efficacy on facilitation of bone healing. Furthermore, the detection of the chemical markers of CDNR in the skin and muscle of the treatment area demonstrated its transdermal properties. However, CDNR did not affect the bone turnover markers in serum of the rats. With its anti-inflammatory and bone formation properties, CDNR is found effective in promoting bone healing