Polyphenols: Modulators of Platelet Function and Platelet Microparticle Generation?

Platelets and platelet microparticles (PMPs) play a key role in the pathophysiology of vascular disorders such as coronary artery disease and stroke. In atherosclerosis, for example, the disruption of the plaque exposes endogenous agonists such as collagen, which activates platelets. Platelet hyper-activation and the high levels of PMPs generated in such situations pose a thrombotic risk that can lead to strokes or myocardial infarctions. Interestingly, dietary polyphenols are gaining much attention due to their potential to mimic the antiplatelet activity of treatment drugs such as aspirin and clopidogrel that target the glycoprotein VI (GPVI)–collagen and cyclooxygenease-1 (COX-1)–thromboxane platelet activation pathways respectively. Platelet function tests such as aggregometry and flow cytometry used to monitor the efficacy of antiplatelet drugs can also be used to assess the antiplatelet potential of dietary polyphenols. Despite the low bioavailability of polyphenols, several in vitro and dietary intervention studies have reported antiplatelet effects of polyphenols. This review presents a summary of platelet function in terms of aggregation, secretion, activation marker expression, and PMP release. Furthermore, the review will critically evaluate studies demonstrating the impact of polyphenols on aggregation and PMP release

Inhibitory Effects of Pulse Bioactive Compounds on Cancer Development Pathways

Previous studies suggest that pulses may have the potential to protect against cancer development by inhibiting pathways that result in the development of cancer. These pathways include those that result in inflammation, DNA damage, cell proliferation, and metastasis. Other studies have demonstrated extracts from pulses have the capacity to induce apoptosis specifically in cancer cells. Compounds reported to be responsible for these activities have included phenolic compounds, proteins and short chain fatty acids. The majority of the studies have been undertaken using in vitro cell culture models, however, there are a small number of in vivo studies that support the hypothesis that pulse consumption may inhibit cancer development. This review highlights the potential benefit of a diet rich in pulse bioactive compounds by exploring the anti-cancer properties of its polyphenols, proteins and short chain fatty acids

Distribution of 5-HT₃, 5-HT₄, and 5-HT₇ receptors along the human colon

BACKGROUND/AIMS: Several disorders of the gastrointestinal tract are associated with abnormal serotonin (5-HT) signaling or metabolism where the 5-HT(3) and 5-HT(4) receptors are clinically relevant. The aim was to examine the distribution of 5-HT(3), 5-HT(4), and 5-HT(7) receptors in the normal human colon and how this is associated with receptor interacting chaperone 3, G protein coupled receptor kinases, and protein LIN-7 homologs to extend previous observations limited to the sigmoid colon or the upper intestine. METHODS: Samples from ascending, transverse, descending, and sigmoid human colon were dissected into 3 separate layers (mucosa, longitudinal, and circular muscles) and ileum samples were dissected into mucosa and muscle layers (n = 20). Complementary DNA was synthesized by reverse transcription from extracted RNA and expression was determined by quantitative or end point polymerase chain reaction. RESULTS: The 5-HT(3) receptor subunits were found in all tissues throughout the colon and ileum. The A subunit was detected in all samples and the C subunit was expressed at similar levels while the B subunit was expressed at lower levels and less frequently. The 5-HT(3) receptor E subunit was mainly found in the mucosa layers. All splice variants of the 5-HT(4) and 5-HT(7) receptors were expressed throughout the colon although the 5-HT(4) receptor d, g, and i variants were expressed less often. CONCLUSIONS: The major differences in 5-HT receptor distribution within the human colon are in relation to the mucosa and muscular tissue layers where the 5-HT(3) receptor E subunit is predominantly found in the mucosal layer which may be of therapeutic relevance