Elizabeth G. Wood

Health: Endothelin-1 synthesis reduced by red wine

Statistical evidence of reduced coronary heart disease in areas of high wine consumption has led to the widespread belief that wine affords a protective effect. Although moderate drinking of any alcohol helps to reduce the incidence of coronary heart disease, there is no clear evidence that red wine confers an additional benefit. Here we show that red wines strongly inhibit the synthesis of endothelin-1, a vasoactive peptide that is crucial in the development of coronary atherosclerosis. Our findings indicate that components specific to red wine may help to prevent coronary heart disease.

Oenology: red wine procyanidins and vascular health.

Regular, moderate consumption of red wine is linked to a reduced risk of coronary heart disease and to lower overall mortality, but the relative contribution of wines alcohol and polyphenol components to these effects is unclear. Here we identify procyanidins as the principal vasoactive polyphenols in red wine and show that they are present at higher concentrations in wines from areas of southwestern France and Sardinia, where traditional production methods ensure that these compounds are efficiently extracted during vinification. These regions also happen to be associated with increased longevity in the population.

Direct type I IFN but not MDA5/TLR3 activation of dendritic cells is required for maturation and metabolic shift to glycolysis after poly IC stimulation.

Type I IFN signaling is indispensable for the maturation of dendritic cells (DCs) that are required to elicit an immune response, and it also controls a shift in cellular metabolism to meet the increased energy demands of DC maturation.

Inhibition by spermine of the induction of nitric oxide synthase in J774.2 macrophages: requirement of a serum factor.

Polyamines are endogenous regulators of various cell functions. Nitric oxide (NO) is a cytostatic and cytotoxic free radical which is produced by the inducible NO synthase (iNOS) in immuno‐stimulated macrophages. We tested whether spermine modulates the induction of iNOS in J774.2 macrophages. Stimulation of macrophages by bacterial lipopolysaccharide (LPS) or γ‐interferon increased the accumulation of nitrite in the culture medium. Spermine (10−6 − 10−4 m) inhibited nitrite production without causing cytotoxicity. This inhibition of NO formation by spermine was significantly reduced when it was given 6 h after LPS. Spermine did not inhibit nitrite accumulation when foetal calf serum was omitted from the tissue culture medium. Thus, spermine is an inhibitor of the induction of iNOS, and its inhibitory activity requires the presence of a serum factor.

Red wine procyanidins and vascular health

Regular, moderate consumption of red wine is linked to a reduced risk of coronary heart disease and to lower overall mortality, but the relative contribution of wines alcohol and polyphenol components to these effects is unclear. Here we identify procyanidins as the principal vasoactive polyphenols in red wine and show that they are present at higher concentrations in wines from areas of southwestern France and Sardinia, where traditional production methods ensure that these compounds are efficiently extracted during vinification. These regions also happen to be associated with increased longevity in the population.

Regulation of Vascular Endothelial Function by Procyanidin-Rich Foods and Beverages†

Flavonoid-rich diets are associated with a lower mortality from cardiovascular disease. This has been linked to improvements in endothelial function. However, the specific flavonoids, or biologically active metabolites, conferring these beneficial effects have yet to be fully defined. In this experimental study of the effect of flavonoids on endothelial function cultured endothelial cells have been used as a bioassay with endothelin-1 (ET-1) synthesis being measured an index of the response. Evaluation of the relative effects of extracts of cranberry juice compared to apple, cocoa, red wine, and green tea showed inhibition of ET-1 synthesis was dependent primarily on their oligomeric procyanidin content. Procyanidin-rich extracts of cranberry juice triggered morphological changes in endothelial cells with reorganization of the actin cytoskeleton and increased immunostaining for phosphotyrosine residues. These actions were independent of antioxidant activity. Comparison of the effects of apple procyanidin monomers through heptamer showed a clear structure-activity relationship. Although monomer, dimer, and trimer had little effect on ET-1 synthesis, procyanidin tetramer, pentamer, hexamer, and heptamer produced concentration-dependent decreases with IC(50) values of 5.4, 1.6, 0.9, and 0.7 microM, respectively. Levels of ET-1 mRNA showed a similar pattern of decreases, which were inversely correlated with increased expression of Kruppel-like factor 2 (KLF2), a key endothelial transcription factor with a broad range of antiatherosclerotic actions including suppression of ET-1 synthesis. Future investigations of procyanidin-rich products should assess the role KLF2 induction plays in the beneficial vascular effects of high flavonoid consumption.

Fructose induces gluconeogenesis and lipogenesis through a SIRT1-dependent mechanism

Consumption of a fructose-rich diet leads to insulin resistance and dyslipidemia in part due to elevated gluconeogenesis and lipogenesis. SIRT1, an NAD(+)-dependent protein deacetylase, can induce gluconeogenesis and lipogenesis. The aim of this study was to determine whether fructose increased hepatic SIRT1, leading to induction of gluconeogenesis and lipogenesis. Rat hepatocytes were incubated with fructose (1-5 mM). SIRT1 protein, SIRT1 activity, and NAD(+)/NADH ratio were measured. The effects of SIRT1 inhibitors (EX-527 and nicotinamide) and activators (SIRT1 activator 3 and SRT1720) and the mitochondrial complex I inhibitor rotenone were examined on fructose-induced increases in gluconeogenesis and lipogenesis. Fructose increased SIRT1 protein, SIRT1 activity, and NAD(+)/NADH ratio. Fructose also induced gluconeogenesis, with increases in peroxisome proliferator-activated receptor coactivator 1-alpha (PGC1α) and phosphoenolpyruvate carboxykinase (PEPCK; gene code Pck1) gene expression, PEPCK activity, and hepatocyte glucose production. In addition, levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase (Hmgcr) and acetyl-coA carboxylase (Acc) mRNA, and intracellular cholesterol were increased. Increases in gluconeogenesis, Hmgcr, Acc, and cholesterol were abolished by SIRT1 inhibitors and rotenone, while SIRT1 activators increased gluconeogenesis, Hmgcr, Acc, Pgc1β, and sterol regulatory element-binding protein 1c (Srebp1c) gene expression. In conclusion, fructose induces gluconeogenesis and lipogenesis through a SIRT1-dependent mechanism, suggesting that induction of hepatic SIRT1 could play a pivotal role in the metabolic changes observed in humans and animals consuming a fructose-rich diet. These results highlight the need for a greater understanding of the role of SIRT1 in metabolic regulation and indicate the potential for adverse effects of SIRT1 activators if used therapeutically.

Expression of cyclooxygenase-2 in rat vascular smooth muscle cells is unrelated to nuclear factor-κB activation

Abstract The promoter region of cyclooxygenase-2 (COX-2) gene contains binding sites for a number of important transcription factors including cyclic AMP response element, nuclear factor-IL6, nuclear factor-κB (NF-κB) and TGF-β response element. Several reports have documented that the activation of NF-κB triggers the expression of COX-2 gene. In the present study, NF-κB was activated by TNF-α in rat aortic smooth muscle cells as demonstrated by electrophoretic mobility shift assay. The activity of NF-κB induced by TNF-α was blocked by calpain inhibitor I, a potent NF-κB inhibitor. However, the activation of NF-κB was not related to the expression of COX-2 induced by TNF-α since calpain inhibitor I blocked the activation of NF-κB but not the expression of COX-2 mRNA or protein. Mutation of rat COX-2 NF-κB-like sites in the promoter region did not significantly reduce the promoter activity. These results suggest that the transcriptional regulation of COX-2 expression by NF-κB depends upon the types of cells studied and that activation of this transcription factor alone does not play an important role in the expression of COX-2 in rat smooth muscle cells.

The procyanidin-induced pseudo laminar shear stress response: a new concept for the reversal of endothelial dysfunction.

Reduced endothelium-dependent vasodilator responses with increased synthesis of ET-1 (endothelin-1) are characteristics of endothelial dysfunction in heart failure and are predictive of mortality. Identification of treatments that correct these abnormalities may have particular benefit for patients who become refractory to current regimens. Hawthorn preparations have a long history in the treatment of heart failure. Therefore we tested their inhibitory effects on ET-1 synthesis by cultured endothelial cells. These actions were compared with that of GSE (grape seed extract), as the vasoactive components of both these herbal remedies are mainly oligomeric flavan-3-ols called procyanidins. This showed extracts of hawthorn and grape seed were equipotent as inhibitors of ET-1 synthesis. GSE also produced a potent endothelium-dependent vasodilator response on preparations of isolated aorta. Suppression of ET-1 synthesis at the same time as induction of endothelium-dependent vasodilation is a similar response to that triggered by laminar shear stress. Based on these results and previous findings, we hypothesize that through their pharmacological properties procyanidins stimulate a pseudo laminar shear stress response in endothelial cells, which helps restore endothelial function and underlies the benefit from treatment with hawthorn extract in heart failure.

Delayed Administration of Pyroglutamate Helix B Surface Peptide (pHBSP), a Novel Nonerythropoietic Analog of Erythropoietin, Attenuates Acute Kidney Injury

In preclinical studies, erythropoietin (EPO) reduces ischemia-reperfusion-associated tissue injury (for example, stroke, myocardial infarction, acute kidney injury, hemorrhagic shock and liver ischemia). It has been proposed that the erythropoietic effects of EPO are mediated by the classic EPO receptor homodimer, whereas the tissue-protective effects are mediated by a heterocomplex between the EPO receptor monomer and the β-common receptor (termed “tissue-protective receptor”). Here, we investigate the effects of a novel, selective-ligand of the tissue-protective receptor (pyroglutamate helix B surface peptide (pHBSP)) in a rodent model of acute kidney injury/dysfunction. Administration of pHBSP (10 µg/kg intraperitoneally (i.p.) 6 h into reperfusion) or EPO (1,000 lU/kg i.p. 4 h into reperfusion) to rats subjected to 30 min ischemia and 48 h reperfusion resulted in significant attenuation of renal and tubular dysfunction. Both pHBSP and EPO enhanced the phosphorylation of Akt (activation) and glycogen synthase kinase 3β (inhibition) in the rat kidney after ischemia-reperfusion, resulting in prevention of the activation of nuclear factor-κB (reduction in nuclear translocation of p65). Interestingly, the phosphorylation of endothelial nitric oxide synthase was enhanced by EPO and, to a much lesser extent, by pHBSP, suggesting that the signaling pathways activated by EPO and pHBSP may not be identical.