Michael J. Puglisi

Modulation of C-Reactive Protein, Tumor Necrosis Factor-α, and Adiponectin by Diet, Exercise, and Weight Loss

Chronic disease has been strongly correlated with inflammation resulting from the bodys release of inflammatory cytokines as a result of injury or infection. Specific interventions promoting weight loss, exercise, or intake of antioxidants have been used by several investigators in an effort to decrease inflammatory cytokines. C-reactive protein (CRP) is produced by the liver and its role in the development of inflammation has been well established. However, the strong association between CRP and risk for heart disease is a more recent discovery. During the inflammation process, the transcriptional activity of nuclear factor kappaB leads to the increased production of inflammatory cytokines associated with atherosclerosis, including tumor necrosis factor-alpha (TNFalpha). Increased concentrations of TNFalpha have been reported in obese patients; thus, weight loss is considered a key intervention to reduce the concentrations of this cytokine. In contrast to CRP and TNFalpha, adiponectin increases during weight loss and insulin sensitivity. Additionally, lower concentrations of this cytokine have been reported in cardiovascular disease and type-2 diabetes. Recent epidemiological studies and clinical interventions have reported contradictory findings related to dietary or exercise interventions and the resulting alterations in plasma cytokines. Part of the discrepancies may be due to the population studied, the time of the treatment, and the lack of weight loss in some studies. Although it is clear from the literature that these cytokines play a major role in the development of chronic disease, the best strategy to favorably alter the inflammatory response is still debatable.

Toll-like Receptor 4 Deficiency Promotes the Alternative Activation of Adipose Tissue Macrophages

Obesity is characterized by adipose tissue (AT) macrophage (ATM) accumulation, which promotes AT inflammation and dysfunction. Toll-like receptor 4 (TLR4) deficiency attenuates AT inflammation in obesity but does not impede the accumulation of ATMs. The purpose of the current study was to determine whether TLR4 deficiency alters ATM polarization. TLR4−/− and wild-type mice were fed a low-fat, high-monounsaturated fat (HFMUFA), or a high-saturated fat (HFSFA) diet for 16 weeks. Further, we used a bone marrow transplant model to determine the influence of hematopoietic cell TLR4 signaling. The metabolic and inflammatory responses to high-fat feeding and ATM phenotype were assessed. Global and hematopoietic cell TLR4 deficiency, irrespective of recipient genotype, produced a shift in ATM phenotype toward an alternatively activated state, which was accompanied by reduced AT inflammation. Despite the observed shift in ATM phenotype, neither global nor hematopoietic cell TLR4 deficiency influenced systemic insulin sensitivity after high-fat feeding. Results of the current study suggest that TLR4 directly influences ATM polarization but question the relevance of TLR4 signaling to systemic glucose homeostasis in obesity.

The role of adipose tissue in mediating the beneficial effects of dietary fish oil

Fish oil improves several features of metabolic syndrome (MetS), such as dyslipidemia, insulin resistance and hepatic steatosis. Fish oil may mediate some of its beneficial effects by modulating the storage and/or secretory functions of adipose tissue (AT). The storage of triglycerides in AT is regulated by the availability of free fatty acids and the degree of lipolysis in AT. Fish oil has been shown to reduce lipolysis in several studies, indicating improved triglyceride storage. Importantly, AT secretes a variety of adipokines and fish oil feeding is associated with remarkable changes in the plasma levels of two key adipokines, adiponectin and leptin. Much attention has been focused on the contribution of adiponectin in fish oil-mediated improvements in MetS. However, emerging evidence also indicates a role of leptin in modulating the components of the MetS upon fish oil feeding. In addition to improving the storage and secretory functions of AT, fish oil, and the n-3 fatty acids found in fish oil, has been shown to reduce inflammation in AT. These effects may be in part a result of activation of peroxisome proliferator-activated receptor γ or inhibition of Toll-like receptor 4. Thus, there is compelling evidence that fish oil mediates its beneficial effects on MetS by improving AT storage and secretory functions and by reducing inflammation.

Impact of macrophage toll-like receptor 4 deficiency on macrophage infiltration into adipose tissue and the artery wall in mice

Aims/hypothesisToll-like receptor 4 (TLR4) is a receptor for saturated fatty acids (SFAs), global deficiency of which has been shown to protect against inflammation, insulin resistance and atherosclerotic lesion formation. Because macrophages express Tlr4 and are important in insulin resistance and atherosclerotic lesion formation due to their infiltration of white adipose tissue (WAT) and the artery wall, respectively, we hypothesised that deficiency of macrophage TLR4 could protect against these disorders.MethodsBone marrow transplantation of agouti, LDL-receptor deficient (Ay/a; Ldlr−/−) mice with marrow from either C57BL/6 or Tlr4−/− mice was performed. Recipient mice with Tlr4+/+ marrow (MθTLR4+/+) or with Tlr4−/− marrow (MθTLR4−/−) were then placed on one of four diets: (1) low fat; (2) high fat; (3) high fat rich in SFAs (HFSFA); and (4) HFSFA supplemented with fish oil.ResultsThere were no differences in body composition or plasma lipids between MθTLR4+/+ and MθTLR4−/− mice on any of the diets. However, we observed a decrease in some macrophage and inflammatory markers in WAT of female low fat-fed MθTLR4−/− mice compared with MθTLR4+/+ mice. MθTLR4−/− mice fed low-fat diet also displayed decreased atherosclerotic lesion area. There were no differences in macrophage accrual in WAT or atherosclerosis between MθTLR4+/+ and MθTLR4−/− mice fed any of the high-fat diets. Finally, no difference was seen in insulin sensitivity between MθTLR4+/+ and MθTLR4−/− mice fed the HFSFA diet.Conclusions/interpretationThese data suggest that under certain dietary conditions, macrophage expression of Tlr4 can be an important mediator of macrophage accumulation in WAT and the artery wall.

Consuming eggs for breakfast influences plasma glucose and ghrelin, while reducing energy intake during the next 24 hours in adult men

We hypothesized that consuming eggs for breakfast would significantly lower postprandial satiety and energy intake throughout the day. Using a crossover design, 21 men, 20 to 70 years old, consumed 2 isoenergetic test breakfasts, in a random order separated by 1 week. The macronutrient composition of the test breakfasts were as follows: (EGG, % CHO/fat/protein = 22:55:23) and (BAGEL, % CHO/fat/protein = 72:12:16). Fasting blood samples were drawn at baseline before the test breakfast and at 30, 60, 120, and 180 minutes after breakfast. After 180 minutes, subjects were given a buffet lunch and asked to eat until satisfied. Subjects filled out Visual Analog Scales (VAS) during each blood draw and recorded food intake the days before and after the test breakfasts. Plasma glucose, insulin, and appetite hormones were analyzed at each time point. Subjects consumed fewer kilocalories after the EGG breakfast compared with the BAGEL breakfast (P< .01). In addition, subjects consumed more kilocalories in the 24-hour period after the BAGEL compared with the EGG breakfast (P < .05). Based on VAS, subjects were hungrier and less satisfied 3 hours after the BAGEL breakfast compared with the EGG breakfast (P < .01). Participants had higher plasma glucose area under the curve (P < .05) as well as an increased ghrelin and insulin area under the curve with BAGEL (P < .05). These findings suggest that consumption of eggs for breakfast results in less variation of plasma glucose and insulin, a suppressed ghrelin response, and reduced energy intake.

Effect of Post-Exercise Supplement Consumption on Adaptations to Resistance Training

Objective: Athletes are interested in nutritional manipulations that may enhance lean tissue gains stimulated by resistance training. Some research demonstrates that acute consumption of food containing protein causes superior muscle protein synthesis compared to isoenergetic foods without protein. This benefit has not been verified in longer-term training studies. We compared body composition and muscle function responses to resistance training in males who consumed a carbohydrate or a multi-macronutrient beverage following each training session. Methods: Nineteen, untrained men (18–25 years) consumed either a milk (MILK) or a carbohydrate-electrolyte (CHO) drink immediately following each workout during a 10 week resistance training program. Muscle strength (1RM for seven exercises), body composition (DXA scan), fasted, resting concentrations of serum total and free testosterone, cortisol, IGF-1, and resting energy expenditure (REE) were measured prior to and at the end of training. Results: Resistance training caused an increase (44 ± 4%, p < 0.001) in muscular strength for all subjects. The training program reduced percent body fat (8%, p < 0.05, −0.9 ± 0.5 kg) and increased fat-free soft tissue (FFST) mass (2%, 1.2 ± 0.3 kg, p < 0.01). MILK tended to increase body weight and FFST mass (p=0.10 and p=0.13, respectively) compared to CHO. Resting total and free testosterone concentrations decreased from baseline values in all subjects (16.7%, 11%, respectively, p < 0.05). Significant changes in fasting IGF-1, cortisol, and REE across training were not observed for either group. Conclusion: Post-resistance exercise consumption of MILK and CHO caused similar adaptations to resistance training. It is possible that a more prolonged training with supplementation period would expand the trend for greater FFST gains in MILK.

Raisins and additional walking have distinct effects on plasma lipids and inflammatory cytokines

BackgroundRaisins are a significant source of dietary fiber and polyphenols, which may reduce cardiovascular disease (CVD) risk by affecting lipoprotein metabolism and inflammation. Walking represents a low intensity exercise intervention that may also reduce CVD risk. The purpose of this study was to determine the effects of consuming raisins, increasing steps walked, or a combination of these interventions on blood pressure, plasma lipids, glucose, insulin and inflammatory cytokines.ResultsThirty-four men and postmenopausal women were matched for weight and gender and randomly assigned to consume 1 cup raisins/d (RAISIN), increase the amount of steps walked/d (WALK) or a combination of both interventions (RAISINS + WALK). The subjects completed a 2 wk run-in period, followed by a 6 wk intervention. Systolic blood pressure was reduced for all subjects (P = 0.008). Plasma total cholesterol was decreased by 9.4% for all subjects (P < 0.005), which was explained by a 13.7% reduction in plasma LDL cholesterol (LDL-C) (P < 0.001). Plasma triglycerides (TG) concentrations were decreased by 19.5% for WALK (P < 0.05 for group effect). Plasma TNF-α was decreased from 3.5 ng/L to 2.1 ng/L for RAISIN (P < 0.025 for time and group × time effect). All subjects had a reduction in plasma sICAM-1 (P < 0.01).ConclusionThis research shows that simple lifestyle modifications such as adding raisins to the diet or increasing steps walked have distinct beneficial effects on CVD risk.

Eggs distinctly modulate plasma carotenoid and lipoprotein subclasses in adult men following a carbohydrate-restricted diet.

We previously reported that carbohydrate restriction (CR) (10-15% en) during a weight loss intervention lowered plasma triglycerides (TG) by 45% in male subjects (P<.001). However, those subjects with a higher intake of cholesterol provided by eggs (640 mg additional cholesterol, EGG group) had higher concentrations of high-density lipoprotein (HDL) cholesterol (P<.0001) than the individuals consuming lower amounts (0 mg of additional cholesterol, SUB group). The objectives of the present study were to evaluate whether CR and egg intake (1) modulate circulating carotenoids and (2) affect the concentrations of plasma apolipoproteins (apo), lipoprotein size and subfraction distribution. CR decreased the number of large and medium very low-density lipoprotein cholesterol subclasses (P<.001), while small low-density lipoprotein (LDL) were reduced (P<.001). In agreement with these observations, a decrease in apo B (P<.01) was observed. In addition, CR resulted in a 133% increase in apo C-II and a 65% decrease in apo C-III (P<.0001). Although an increase of the larger LDL subclass was observed for all subjects, the EGG group had a greater increase (P<.05). The EGG group also presented a higher number of large HDL particles (P<.01) compared to the SUB group. Regarding carotenoids, CR resulted in no changes in dietary or plasma alpha- or beta-carotene and beta-cryptoxanthin, while there was a significant reduction in both dietary and plasma lycopene (P<.001). In contrast, dietary lutein and zeaxanthin were increased during the intervention (P<.05). However, only those subjects from the EGG group presented higher concentrations of these two carotenoids in plasma, which were correlated with the higher concentrations of large LDL observed in the EGG group. These results indicate that CR favorably alters VLDL metabolism and apolipoprotein concentrations, while the components of the egg yolk favor the formation of larger LDL and HDL leading to an increase in plasma lutein and zeaxanthin.

A-002 (Varespladib), a phospholipase A2 inhibitor, reduces atherosclerosis in guinea pigs

BackgroundThe association of elevated serum levels of secretory phospholipase A2 (sPLA2) in patients with cardiovascular disease and their presence in atherosclerotic lesions suggest the participation of sPLA2 enzymes in this disease. The presence of more advanced atherosclerotic lesions in mice that overexpress sPLA2 enzymes suggest their involvement in the atherosclerotic process. Therefore, the sPLA2 family of enzymes could provide reasonable targets for the prevention and treatment of atherosclerosis. Thus, A-002 (varespladib), an inhibitor of sPLA2enzymes, is proposed to modulate the development of atherosclerosis.MethodsTwenty-four guinea pigs were fed a high saturated fat, high cholesterol diet (0.25%) for twelve weeks. Animals were treated daily with A-002 (n = 12) or vehicle (10% aqueous acacia; n = 12) by oral gavage. After twelve weeks, animals were sacrificed and plasma, heart and aorta were collected. Plasma lipids were measured by enzymatic methods, lipoprotein particles size by nuclear magnetic resonance, aortic cytokines by a colorimetric method, and aortic sinus by histological analyses.ResultsPlasma total cholesterol, HDL cholesterol and triglycerides were not different among groups. However, the levels of inflammatory cytokines interleukin (IL)-10, IL-12 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were significantly reduced in the treatment group. This group also had a significant 27% reduction in cholesterol accumulation in aorta compared with placebo group. Morphological analysis of aortic sinus revealed that the group treated with A-002 reduced atherosclerotic lesions by 24%.ConclusionThe use of A-002 may have a beneficial effect in preventing diet-induced atherosclerosis in guinea pigs.

Macronutrient Composition and Increased Physical Activity Modulate Plasma Adipokines and Appetite Hormones during a Weight Loss Intervention

BACKGROUND We have shown previously that in overweight premenopausal women, changes in macronutrient composition and increasing the number of steps walked per day favorably affect body composition and plasma lipid profiles. As a follow-up, we evaluated the effect of moderate carbohydrate intake and increased physical activity on inflammation and regulation of appetite. METHODS Seventy premenopausal women with a body mass index (BMI) between 25 and 37 kg/m(2) participated in a 10-week weight loss intervention program consisting of the following macronutrient energy distribution: 40% carbohydrate, 30% fat, and 30% protein, in addition to a progressive increase in the number of steps taken per day. Plasma adiponectin, intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), leptin, and ghrelin levels were assessed at baseline and after 10 weeks. RESULTS Subjects reduced body weight by 4.5%, waist circumference (WC) by 6.4%, and trunk fat by 4.6%. Plasma insulin and insulin resistance assessed by homeostasis model assessment (HOMA) were reduced after 10 weeks (p < 0.01). Plasma adiponectin was increased by 11% (p < 0.05), and ICAM-1 levels were decreased (p < 0.05) after 10 weeks. A negative correlation was found between changes in insulin and changes in adiponectin between baseline and 10 weeks (r = -0.397, p < 0.01), indicating a role of adiponectin in increasing insulin sensitivity. In addition, plasma ghrelin levels were increased by 17% (p < 0.001), indicating a signal for increased appetite associated with weight loss. CONCLUSIONS These studies indicate that weight loss interventions involving moderate changes in dietary carbohydrate and increases in physical activity favorably affect insulin sensitivity and decrease inflammation.