The Inhibition of Metabolic Inflammation by EPA Is Associated with Enhanced Mitochondrial Fusion and Insulin Signaling in Human Primary Myotubes.

BACKGROUND: Sustained fuel excess triggers low-grade inflammation that can drive mitochondrial dysfunction, a pivotal defect in the pathogenesis of insulin resistance in skeletal muscle. OBJECTIVES: This study aimed to investigate whether inflammation in skeletal muscle can be prevented by EPA, and if this is associated with an improvement in mitochondrial fusion, membrane potential, and insulin signaling. METHODS: Human primary myotubes were treated for 24 h with palmitic acid (PA, 500 µM) under hyperglycemic conditions (13 mM glucose), which represents nutrient overload, and in the presence or absence of EPA (100 µM). After the treatments, the expression of peroxisome proliferator-activated receptor γ coactivator 1-α (PPARGC1A) and IL6 was assessed by q-PCR. Western blot was used to measure the abundance of the inhibitor of NF-κB (IKBA), mitofusin-2 (MFN2), mitochondrial electron transport chain complex proteins, and insulin-dependent AKT (Ser473) and AKT substrate 160 (AS 160; Thr642) phosphorylation. Mitochondrial dynamics and membrane potential were evaluated using immunocytochemistry and the JC-1 (tetraethylbenzimidazolylcarbocyanine iodide) dye, respectively. Data were analyzed using 1-factor ANOVA followed by Tukey post hoc test. RESULTS: Nutrient excess activated the proinflammatory NFκB signaling marked by a decrease in IKBA (40%; P < 0.05) and the upregulation of IL6 mRNA (12-fold; P < 0.001). It also promoted mitochondrial fragmentation (53%; P < 0.001). All these effects were counteracted by EPA. Furthermore, nutrient overload-induced drop in mitochondrial membrane potential (6%; P < 0.05) was prevented by EPA. Finally, EPA inhibited fuel surplus-induced impairment in insulin-mediated phosphorylation of AKT (235%; P < 0.01) and AS160 (49%; P < 0.05). CONCLUSIONS: EPA inhibited NFκB signaling, which was associated with an attenuation of the deleterious effects of PA and hyperglycemia on both mitochondrial health and insulin signaling in human primary myotubes. Thus, EPA might preserve skeletal muscle metabolic health during sustained fuel excess but this requires confirmation in human clinical trials.

Consumption of an Oil Palm Fruit Extract Promotes Large Bowel Health in Rats.

Oil palm fruit is widely used for edible oils, but the health benefits of other components are relatively unknown. We examined if consuming a polyphenol-rich extract of the fruit, from a vegetation by-product of oil processing, which also contains fibre, has gastro-intestinal benefits in rats on a Western-type diet (WD). The oil palm preparation (OPP) was added to food (OPP-F) or drinking water (OPP-D) to provide 50 mg of gallic acid equivalents (GAE)/d and compared to effects of high amylose maize starch (HAMS; 30%) in the diet or green tea extract (GT; 50 mg GAE/d) in drinking water over 4 wk. OPP treatments induced some significant effects (P < 0.05) compared to WD. OPP-D increased caecal digesta mass, caecal digesta concentrations of total SCFA, acetate and propionate (OPP-F increased caecal butyrate concentration), the numbers of mucus-producing goblet cells per colonic crypt, and caecal digesta abundance of some bacteria which may provide benefit to the host (Faecalibacterium prausnitzii, Akkermansia muciniphila and Ruminococcus gnavus). HAMS induced similar effects but with greater potency and had a broader impact on microbe populations, whereas GT had minimal impacts. These results suggest dietary OPP may benefit the large bowel.

Naturally occurring anthocyanin cyanidin-3-rutinoside possesses inherent vasorelaxant actions and prevents methylglyoxal-induced vascular dysfunction in rat aorta and mesenteric arterial bed.

Cyanidin-3-rutinoside (C3R) possesses anti-oxidant, anti-inflammatory and anti-glycation properties. Methylglyoxal (MG), a highly reactive dicarbonyl aldehyde by-product of glycolysis, is a precursor of advanced glycation end products and contributes to vascular dysfunction, particularly during hyperglycemia. We investigated the possible inherent vasoactivity of C3R, and its effectiveness against MG-induced vascular abnormalities in isolated blood vessel preparations from male Wistar Kyoto rat. C3R induced vasorelaxation concentration-dependently in aortic rings (92% maximum relaxation; EC50: 2.43±0.57µM) and in perfused-mesenteric arterial bed (61% maximum relaxation; EC50: 25.0±1.26µM) pre-contracted with noradrenaline (NA). The vasorelaxation actions of C3R were endothelium-dependent and mediated primarily via nitric oxide (NO) as evidenced by the absence of relaxation in endothelium-denuded preparations as well as in the presence of Nω-nitro-l-arginine, an inhibitor of NO synthase. Intravenous administration of C3R (15-25µmol/kg body weight) in anesthetized rats significantly reduced mean arterial blood pressure (11-23%). Pre-treatment with MG (500µM) potentiated the vasoconstriction elicited by NA and impaired vasorelaxation induced by acetylcholine that was fully restored to basal levels in the presence of C3R (3µM). Taken together, C3R exerts multiple benefits on the vasculature, complementing its potential as a candidate anti-glycation agent.

Microencapsulated krill and tuna oil blend raises plasma long-chain n-3 polyunsaturated fatty acid levels compared to tuna oil with similar increases in ileal contractility in rats.

Long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) may be more bioavailable from krill oil compared to fish oil due to their phospholipid structure. We tested whether a microencapsulated krill and tuna oil blend (ME-TOKO) provided greater LC n-3 PUFA bioavailability, improved blood lipid profiles and increased intestinal contractility compared to microencapsulated tuna oil (ME-TO). Rats were divided into three groups to receive isocaloric diets containing ME-TO, ME-TOKO and microencapsulated olive oil (ME-OO) at 0.3 or 2 g/100 g for 4 weeks. Final body and organ weights, feed intake and waste output were similar. ME-TOKO rats had higher plasma total LC n-3 PUFA levels compared to ME-TO, but liver LC n-3 PUFA levels and plasma triglyceride and cholesterol levels were similar in non-fasted rats. Diets containing 2% ME-TO and ME-TOKO also showed similar increases in ileal contractility. In summary, ME-TO bioavailability of LC n-3 PUFA was similar to ME-TOKO.

Short term effects of palm-tocotrienol and palm-carotenes on vascular function and cardiovascular disease risk: A randomised controlled trial.

BACKGROUND AND AIMS: In vitro, ex vivo and animal studies suggest palm-based tocotrienols and carotenes enhance vascular function, but limited data in humans exists. The aim was to examine the effects of palm-tocotrienols (TRF- 80) and palm-carotene (CC-60) supplementation on vascular function and cardiovascular disease (CVD) risk factors in adults at increased risk of impaired vascular function. METHODS: Ninety men and women (18-70 yr, 20-45 kg/m2) with type 2 diabetes, impaired fasting glucose and/or elevated waist circumference were randomised to consume either TRF-80 (420 mg/day tocotrienol + 132 mg/day tocopherol), CC-60 (21 mg/day carotenes) or placebo (palm olein) supplements for 8 weeks. Brachial artery flow-mediated dilation (FMD), other physiological and circulatory markers of vascular function, lipid profiles, glucose, insulin and inflammatory markers were assessed pre- and post-supplementation. Pairwise comparisons were performed using mixed effects longitudinal models (n = 87, n = 3 withdrew before study commencement). RESULTS: Plasma α- and ß-carotene and α-, δ- and γ-tocotrienol concentrations increased in CC-60 and TRF-80 groups, respectively, compared to placebo (mean ± SE difference in total plasma carotene change between CC-60 and placebo: 1.5 ± 0.13 µg/ml, p < 0.0001; total plasma tocotrienol change between TRF-80 and placebo: 0.36 ± 0.05 µg/ml, p < 0.0001). Neither FMD (treatment x time effect for CC-60 vs. placebo, p = 0.71; TRF-80 vs. placebo, p = 0.80) nor any other vascular function and CVD outcomes were affected by treatments. CONCLUSIONS: CC-60 and TRF-80 supplementation increased bioavailability of palm-based carotenes and tocotrienols but had no effects, superior or detrimental, on vascular function or CVD risk factors.

Lipid-Induced Insulin Resistance in Skeletal Muscle: The Chase for the Culprit Goes from Total Intramuscular Fat to Lipid Intermediates, and Finally to Species of Lipid Intermediates.

The skeletal muscle is the largest organ in the body. It plays a particularly pivotal role in glucose homeostasis, as it can account for up to 40% of the body and for up to 80%-90% of insulin-stimulated glucose disposal. Hence, insulin resistance (IR) in skeletal muscle has been a focus of much research and review. The fact that skeletal muscle IR precedes ß-cell dysfunction makes it an ideal target for countering the diabetes epidemic. It is generally accepted that the accumulation of lipids in the skeletal muscle, due to dietary lipid oversupply, is closely linked with IR. Our understanding of this link between intramyocellular lipids (IMCL) and glycemic control has changed over the years. Initially, skeletal muscle IR was related to total IMCL. The inconsistencies in this explanation led to the discovery that particular lipid intermediates are more important than total IMCL. The two most commonly cited lipid intermediates for causing skeletal muscle IR are ceramides and diacylglycerol (DAG) in IMCL. Still, not all cases of IR and dysfunction in glycemic control have shown an increase in either or both of these lipids. In this review, we will summarise the latest research results that, using the lipidomics approach, have elucidated DAG and ceramide species that are involved in skeletal muscle IR in animal models and human subjects.

Rise in DPA Following SDA-Rich Dietary Echium Oil Less Effective in Affording Anti-Arrhythmic Actions Compared to High DHA Levels Achieved with Fish Oil in Sprague-Dawley Rats.

Stearidonic acid (SDA; C18:4n-3) has been suggested as an alternative to fish oil (FO) for delivering health benefits of C ≥ 20 long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA). Echium oil (EO) represents a non-genetically-modified source of SDA available commercially. This study compared EO and FO in relation to alterations in plasma and tissue fatty acids, and for their ability to afford protection against ischemia-induced cardiac arrhythmia and ventricular fibrillation (VF). Rats were fed (12 weeks) diets supplemented with either EO or FO at three dose levels (1, 3 and 5% w/w; n = 18 per group). EO failed to influence C22:6n-3 (DHA) but increased C22:5n-3 (DPA) in tissues dose-dependently, especially in heart tissue. Conversely, DHA in hearts of FO rats showed dose-related elevation; 14.8%-24.1% of total fatty acids. Kidney showed resistance for incorporation of LC n-3 PUFA. Overall, FO provided greater cardioprotection than EO. At the highest dose level, FO rats displayed lower (p < 0.05) episodes of VF% (29% vs. 73%) and duration (22.7 ± 12.0 vs. 75.8 ± 17.1 s) than the EO group but at 3% EO was comparable to FO. We conclude that there is no endogenous conversion of SDA to DHA, and that DPA may be associated with limited cardiac benefit.

Inhibition of Angiotensin Converting Enzyme, Angiotensin II Receptor Blocking, and Blood Pressure Lowering Bioactivity across Plant Families.

Hypertension is a major risk factor for coronary heart disease, kidney disease, and stroke. Interest in medicinal or nutraceutical plant bioactives to reduce hypertension has increased dramatically. The main biological regulation of mammalian blood pressure is via the renin-angiotensin-aldosterone system. The key enzyme is angiotensin converting enzyme (ACE) that converts angiotensin I into the powerful vasoconstrictor, angiotensin II. Angiotensin II binds to its receptors (AT1) on smooth muscle cells of the arteriole vasculature causing vasoconstriction and elevation of blood pressure. This review focuses on the in vitro and in vivo reports of plant-derived extracts that inhibit ACE activity, block angiotensin II receptor binding and demonstrate hypotensive activity in animal or human studies. We describe 74 families of plants that exhibited significant ACE inhibitory activity and 16 plant families with potential AT1 receptor blocking activity, according to in vitro studies. From 43 plant families including some of those with in vitro bioactivity, the extracts from 73 plant species lowered blood pressure in various normotensive or hypertensive in vivo models by the oral route. Of these, 19 species from 15 families lowered human BP when administered orally. Some of the active plant extracts, isolated bioactives and BP-lowering mechanisms are discussed.

Bioequivalence of n-3 fatty acids from microencapsulated fish oil formulations in human subjects.

Fish oil n-3 fatty acids (FA) have known health benefits. Microencapsulation stabilises and protects fish oil from oxidation, enabling its incorporation into foods. The aim of the present study was to compare the bioavailability of n-3 FA delivered as two microencapsulated fish oil-formulated powders or fish oil gel capsules (FOGC) taken with a flavoured milk in healthy participants. Formulation 1 (F1) composed of a heated mixture of milk protein-sugar as an encapsulant, and formulation 2 (F2) comprised a heated mixture of milk protein-sugar-resistant starch as an encapsulant. Participants consumed 4 g fish oil (approximately 1·0 g EPA and DHA equivalent per dose). Bioavailability was assessed acutely after ingestion of a single dose by measuring total plasma FA composition over a period of 48 h (n 14) using a randomised cross-over design, and over the short term for a period of 4 weeks using an unblinded parallel design (after daily supplementation) by measuring total plasma and erythrocyte FA composition at baseline and at 2 and 4 weeks (n 47). In the acute study, F1 greatly increased (% Δ) plasma EPA and total n-3 FA levels at 2 and 4 h and DHA levels at 4 h compared with FOGC. The time to reach maximal plasma values (T(max)) was shorter for F1 than for FOGC or F2. In the short-term study, increases in plasma and erythrocyte n-3 FA values were similar for all treatments and achieved an omega-3 index in the range of 5·8-6·3 % after 4 weeks. Overall, the results demonstrated human bioequivalence for microencapsulated fish oil powder compared with FOGC.

Resistant starch alters colonic contractility and expression of related genes in rats fed a Western diet.

BACKGROUND AND AIM: Dietary fiber shortens gut transit time, but data on the effects of fiber components (including resistant starch, RS) on intestinal contractility are limited. We have examined RS effects in male Sprague-Dawley rats fed either a high-amylose maize starch (HAMS) or a wholemeal made from high-amylose wheat (HAW) on ileal and colonic contractility ex vivo and expression of genes associated with smooth muscle contractility. METHODS: Rats were fed diets containing 19 % fat, 20 % protein, and either low-amylose maize starch (LAMS), HAMS, wholemeal low-amylose wheat (LAW) or HAW for 11 week. Isolated ileal and proximal colonic sections were induced to contract electrically, or by receptor-independent (KCl) or receptor-dependent agents. Colonic gene expression was assessed using an Affymetrix microarray. RESULTS: Ileal contractility was unaffected by treatment. Maximal proximal colonic contractility induced electrically or by angiotensin II or carbachol was lower for rats fed HAMS and LAW relative to those fed LAMS (P < 0.05). The colonic expression of genes, including cholinergic receptors (Chrm2, Chrm3), serotonin receptors (Htr5a, Htr7), a protease-activated receptor (F2r), a prokineticin receptor (Prokr1), prokineticin (Prok1), and nitric oxide synthase 2 (Nos2), was altered by dietary HAMS relative to LAMS (P < 0.05). HAW did not significantly affect these genes or colonic contractility relative to effects of LAMS. CONCLUSIONS: RS and other fiber components could influence colorectal health through modulation of stool transit time via effects on muscular contractility.

Dietary fish oil preserves cardiac function in the hypertrophied rat heart.

Regular fish or fish oil intake is associated with a low incidence of heart failure clinically, and fish oil-induced reduction in cardiac remodelling seen in hypertrophy models may contribute. We investigated whether improved cardiac energy efficiency in non-hypertrophied hearts translates into attenuation of cardiac dysfunction in hypertrophied hearts. Male Wistar rats (n 33) at 8 weeks of age were sham-operated or subjected to abdominal aortic stenosis to produce pressure-overload cardiac hypertrophy. Starting 3 weeks post-operatively to follow initiation of hypertrophy, rats were fed a diet containing 10 % olive oil (control) or 5 % fish oil (ROPUFA® 30 (17 % EPA, 10 % DHA))+5 % olive oil (FO diet). At 15 weeks post-operatively, ventricular haemodynamics and oxygen consumption were evaluated in the blood-perfused, isolated working heart. Resting and maximally stimulated cardiac output and external work were >60 % depressed in hypertrophied control hearts but this was prevented by FO feeding, without attenuating hypertrophy. Cardiac energy efficiency was lower in hypertrophy, but greater in FO hearts for any given cardiac mass. Coronary blood flow, restricted in hypertrophied control hearts, increased with increasing work in hypertrophied FO hearts, revealing a significant coronary vasodilator reserve. Pronounced cardiac dysfunction in hypertrophied hearts across low and high workloads, indicative of heart failure, was attenuated by FO feeding in association with membrane incorporation of n-3 PUFA, principally DHA. Dietary fish oil may offer a new approach to balancing the high oxygen demand and haemodynamic requirements of the failing hypertrophied heart independently of attenuating hypertrophy.

Role of ω3 long-chain polyunsaturated fatty acids in reducing cardio-metabolic risk factors.

Cardiovascular disease is the leading cause of mortality in many economically developed nations, and its incidence is increasing at a rapid rate in emerging economies. Diet and lifestyle issues are closely associated with a myriad of cardiovascular disease risk factors including abnormal plasma lipids, hypertension, insulin resistance, diabetes and obesity, suggesting that diet-based approaches may be of benefit. Omega-3 longchain-polyunsaturated fatty acids (ω3 LC-PUFA) are increasingly being used in the prevention and management of several cardiovascular risk factors. Both the ω3 and ω6 PUFA families are considered essential, as the human body is itself unable to synthesize them. The conversion of the two precursor fatty acids - linoleic acid (18:2ω6) and α-linoleic acid (α18:3ω3) - of these two pathways to longer (≥C(20)) PUFA is inefficient. Although there is an abundance of ω6 PUFA in the food supply; in many populations the relative intake of ω3 LC-PUFA is low with health authorities advocating increased consumption. Fish oil, rich in eicosapentaenoic (EPA, 20:5ω3) and docosahexaenoic (DHA, 22:6ω3) acids, has been found to cause a modest reduction in blood pressure at a dose level of >3g/d both in untreated and treated hypertensives. Whilst a multitude of mechanisms may contribute to the blood pressure lowering action of ω3 LC-PUFA, improved vascular endothelial cell function appears to play a central role. Recent studies which evaluated the potential benefits of fish oil in type-2 diabetes have helped to alleviate concerns raised in some previous studies which used relatively large dose (5-8 g/d) and reported a worsening of glycemic control. Several meta-analyses have confirmed that the most consistent action of ω3 LC-PUFA in insulin resistance and type-2 diabetes is the reduction in triglycerides. In some studies, fish oil has been found to cause a small rise in LDL-cholesterol, but a change in the LDL particle size, from the smaller more atherogenic form to the larger, less damaging particle size, have also been noted. ω3 LC-PUFA are effective modulators of the inflammation that accompanies several cardio-metabolic abnormalities. Taking into consideration the pleiotropic nature of their actions, it can be concluded that dietary supplementation with ω3 LC-PUFA will lead to improvements in cardio-metabolic health parameters. These fatty acids pose only minor side effects and more importantly, do not interact adversely with the common drug therapies used in the management and treatment of hypertension, dyslipidemia, type-2 diabetes, and obesity/metabolic syndrome, but in some instances work synergistically, thereby providing additional cardiovascular benefits.

Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse.

BACKGROUND AND AIMS: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients. The major aims of this study were to: 1) characterize the opioid-specific antagonism of morphine-induced inhibition of electrically driven contraction of the small intestine of mice, rats, and guinea pigs; and 2) test if the oral delivery of small milk-derived opioid antagonist peptides could block morphine-induced inhibition of intestinal transit in mice. METHODS: Mouse, rat, and guinea pig intact ileal sections were electrically stimulated to contract and inhibited with morphine in vitro. Morphine inhibition was then blocked by opioid subtype antagonists in the mouse and guinea pig. Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques. RESULTS: The guinea pig tissue was more sensitive to morphine inhibition compared with the mouse or the rat (IC(50) [half maximal inhibitory concentration] values as nmol/L ± SEM were 34 ± 3, 230 ± 13, and 310 ± 14 respectively) (P < 0.01). The inhibitory influence of opioid agonists (IC(50)) in electrically driven ileal mouse preparations were DADLE ([D-Ala(2), D-Leu(5)]-enkephalin) ≥ met-enkephalin ≥ dynorphin A ≥ DAMGO ([D-Ala(2), N-Me-Phe(4), Glyol(5)]-enkephalin) > morphine > morphiceptin as nmol/L 13.9, 17.3, 19.5, 23.3, 230, and 403 respectively. The mouse demonstrated predominantly κ- and δ-opioid receptor activity with a smaller µ-opioid receptor component. Both mouse and guinea pig tissue were sensitive to casoxin 4 antagonism of morphine inhibition of contraction. In contrast to naloxone, relatively high oral doses of the µ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit. CONCLUSIONS: Casoxin 4 reverses morphine-induced inhibition of contraction in mice and guinea pigs in vitro but fails to influence morphine inhibition of mouse small intestinal transit by the oral route.

Butyrylated starch increases large bowel butyrate levels and lowers colonic smooth muscle contractility in rats.

The short-chain fatty acids acetate, propionate, and butyrate are produced by colonic bacterial fermentation of carbohydrates. Butyrate is important in the regulation of the colonocyte cell cycle and gut motility and may also reduce the risk of large bowel cancer. We have shown that dietary butyrylated starch can deliver butyrate to the large bowel in a sustained manner. We hypothesized that ingestion of butyrylated starch increases large bowel butyrate levels and decreases colonic contractility. Groups of male Sprague-Dawley rats (n = 8) were fed AIN-93G-based diet containing a highly digestible low-amylose maize starch (LAMS) control or 5% or 10% butyrylated LAMS (LAMSB) for 10 days. We found that cecal but not colonic tissue weight as well as cecal and distal colonic digesta weights and fecal output were higher in LAMSB fed rats. Butyrylated LAMS lowered digesta pH throughout the large bowel. Cecal, proximal, and distal colonic butyrate pools and portal venous butyrate concentrations were higher in rats fed LAMSB. Electrically stimulated and receptor-dependent carbachol and prostaglandin E(2)-induced isotonic contractions were lower in isolated intact sections of proximal colon (P < .05) but not the terminal ileum after 10% LAMSB ingestion. These results demonstrated that elevation of butyrate levels in the large bowel of the rat correlated with reduction of contractile activity of the colonic musculature, which may assist in the reabsorption of water and minerals.

Radioligand binding assays: application of [(125)I]angiotensin II receptor binding.

Angiotensin II (AngII) is an octapeptide hormone with a key role in blood pressure regulation. AngII increases blood pressure by stimulating G protein-coupled receptors in vascular smooth muscle. AngII receptors are therefore an important target in patients with high blood pressure. Strategies to lower high blood pressure (hypertension) include the use of drugs that compete for AngII at the angiotensin II Type 1 receptors (ATR) using ATR antagonists (e.g., irbesartan, valsartan, and losartan). This chapter will demonstrate the subtype specificity of ATR binding and we discuss some of the key experiments that are necessary in optimizing some of the parameters for GPCR screening. The latter protocols include saturation binding to determine K (d) and B (max), as well as competition/inhibition experiments to determine the IC(50) of binding. For these experiments we have used rat liver membranes which express ATR (type 1a) in relatively abundant amounts. Additionally, rat liver membrane preparations can be easily prepared in "bulk," frozen away for extended periods (up to 1 year) and used when necessary with no loss of receptor binding activity using the radiolabeled angiotensin II analogue, [(125)I][Sar(1),I le(8)]AngII.

Cardiovascular biology of interleukin-6.

Interleukin-6 (IL-6) is a multifunctional pro-inflammatory cytokine that is tightly regulated and expressed at low levels in healthy individuals. Increased IL-6 expression has been associated with a variety of diseases, including inflammatory conditions such as atherosclerosis and cardiovascular disease (obesity, myocardial infarction and type II diabetes). Cytokines including IL-6 and tumour necrosis factor alpha as well as acute phase proteins such as C-reactive protein (CRP) and fibrinogen are key biochemical risk factors for the development of these disease conditions. IL-6 is the key cytokine responsible for the stimulus of synthesis and secretion of CRP. IL-6 activates cell surface signalling via the assembly of IL-6, the IL-6 receptor (IL-6R) and the signalling receptor gp130. Assembly of the (hexameric) signalling complex of IL-6, IL-6R and gp130 occurs in a sequential manner and therefore this signalling complex lends itself to several potential sites for drug targeting. This review discusses some of the mechanisms of IL-6 signalling on various aspects of cardiovascular biology as well as some recent developments in drug targeting of this complex.

Site specific delivery of microencapsulated fish oil to the gastrointestinal tract of the rat.

The aim of this study was to design food grade matrices to deliver microencapsulated fish oil to the large bowel of the rat where the potential exists to retard inflammation and cancer development. Digestion in simulated gastric fluid and intestinal fluid demonstrated that only 4-6% of oil was released from the following dried emulsion formulations: 50% fish oil encapsulated in heated casein-glucose-dried glucose syrup (1:1:1) (Cas-Glu-DGS-50); 25% fish oil in casein-modified resistant starch (Hylon VII) (1:1) (Cas-Hylon-25); or 25% fish oil in Cas-Glu-Hylon (1:1:1) (Cas-Glu-Hylon-25). A short-term gavage study (0-12 h) with fish oil and Cas-Glu-DGS-50 demonstrated the appearance of fish oil long chain (LC) n-3 polyunsaturated fatty acids (PUFA) into the plasma indicating specific small intestinal absorption with little LC n-3 PUFA reaching the large bowel. In a 2-week-long term, daily gavage study, the bioavailability of fish oil and fish oil in Cas-Glu-DGS-50 or Cas-Hylon-25 demonstrated that fish oil and Cas-Glu-DGS-50 LC n-3 PUFA were incorporated into the tissue of the small intestine and colon, whereas Cas-Hylon-25 was resistant to degradation in the small intestine. The use of modified Hylon VII for targeted colonic delivery was confirmed in the final short-term gavage study (0-14 h) using Cas-Glu-Hylon-25 with [(14)C]-trilinolenin as a marker incorporated into the microcapsules, where up to 60% of the labeled oil reached the large bowel. Depending on the microencapsulating matrix employed, fish oil can be delivered selectively to the small intestine or to a high degree to the large bowel.

Cardioprotective actions of grape polyphenols.

The aim of this review is to discuss the accumulating evidence that suggests that grape extracts and purified grape polyphenols possess a diverse array of biological actions and may be beneficial in the prevention of some inflammatory-mediated diseases including cardiovascular disease. The active components from grape extracts, which include the grape seed, grape skin, and grape juice, that have been identified thus far include polyphenols such as resveratrol, phenolic acids, anthocyanins, and flavonoids. All possess potent antioxidant properties and have been shown to decrease low-density lipoprotein-cholesterol oxidation and platelet aggregation. These compounds also possess a range of additional cardioprotective and vasoprotective properties including antiatherosclerotic, antiarrhythmic, and vasorelaxation actions. Although not exclusive, antioxidant properties of grape polyphenols are likely to be central to their mechanism(s) of action, which also include cellular signaling mechanisms and interactions at the genomic level. This review discusses some of the evidence favoring the consumption of grape extracts rich in polyphenols in the prevention of cardiovascular disease. Consumption of grape and grape extracts and/or grape products such as red wine may be beneficial in preventing the development of chronic degenerative diseases such as cardiovascular disease.

Grape seed and red wine polyphenol extracts inhibit cellular cholesterol uptake, cell proliferation, and 5-lipoxygenase activity.

Accumulating evidence suggests that grape seed and wine polyphenol extracts possess a diverse array of actions and may be beneficial in the prevention of inflammatory-mediated disease such as cardiovascular disease and cancer. This study aimed to determine whether the reported pleiotropic effects of several polyphenolic extracts from grape seed products or red wine would also include inhibition of cholesterol uptake and cell proliferation, and inhibit a known specific target of the inflammatory process, that is, 5-lipoxygenase (5-LOX). Incubation of HT29, Caco2, HepG2, or HuTu80 cells in a medium containing [(3)H]cholesterol in the presence of a grape seed extract (GSE) or red wine polyphenolic compounds (RWPCs) inhibited [(3)H]cholesterol uptake by up to 66% (which appeared maximal). The estimated IC(50) values were 60 and 83 microg/mL for RWPC and GSE, respectively. Similar cholesterol uptake inhibitory effects were observed using the fluorescent cholesterol analogue NBD cholesterol. The inhibition of cholesterol uptake was independent of the sample's (GSE and RWPC) potent antioxidative capacity. Red wine polyphenolic compound and GSE dose dependently inhibited HT29 colon adenocarcinoma cell proliferation, which was accompanied by an increase in apoptosis. In addition, RWPC and GSE inhibited 5-LOX activity with the IC(50) values being 35 and 13 microg/mL, respectively. Two of 3 other GSEs tested also significantly inhibited 5-LOX activity. Inhibition of cholesterol uptake and proinflammatory 5-LOX activity may be beneficial in preventing the development of chronic degenerative diseases such as cardiovascular disease and cancer.

Nandrolone potentiates arrhythmogenic effects of cardiac ischemia in the rat.

Anabolic steroid abuse has been associated with thrombosis and arteriosclerosis, both of which predispose to myocardial ischemia and infarction. However, there are reports of sudden cardiac death in the absence of thrombus and atheroma following anabolic steroid use. Although treatment with the commonly abused steroid, nandrolone, has been shown to decrease recovery of systolic function following ischemia in isolated rat hearts, it is unknown whether anabolic steroids can increase the incidence of fatal arrhythmia associated with cardiac ischemia. Anesthetized male Sprague-Dawley rats were administered vehicle or nandrolone (10-160 microg/kg/min iv) 10 min prior to 15-min occlusion of the left anterior descending coronary artery followed by 10-min reperfusion. Nandrolone, in this dose range, did not significantly change heart rate, blood pressure, or cardiac rhythm in the absence of ischemia. However, the fraction of rats surviving ischemia was significantly (p < 0.05) decreased by nandrolone at both 40 and 160 microg/kg/min, while survival time during ischemia was decreased significantly (p < 0.001) by nandrolone 160 microg/kg/min. An increase (p < 0.05) in the duration of ventricular fibrillation was noted at the highest compared to the lowest dose of nandrolone, corresponding to a significant increase in the fraction of rats experiencing ventricular fibrillation (p < 0.01). Nandrolone had no effect on the frequency or duration of ventricular fibrillation or survival time during reperfusion. Although the mechanisms underlying these effects are currently unclear, they indicate that exposure to anabolic steroids in combination with transient reductions in coronary blood flow may explain some reports of sudden cardiac death in anabolic steroid users.