Consumption of a high-fat meal was associated with an increase in monocyte adhesion molecules, scavenger receptors, and Propensity to Form Foam Cells.

BACKGROUND: Macrophage-derived foam cells are the predominant component of arterial plaques in the early stages of atherosclerosis. One factor that poses a major risk for plaque development is high levels of plasma low-density lipoprotein (LDL) as a result of a high-fat meal. In order to better understand how an individuals' diet affects arterial plaque deposition via the process of foam cell formation, we measured the acute circulating monocyte activity response after consuming a high-fat meal (85% of daily fat allowance). MATERIALS AND METHODS: Venous blood samples from 17 participants were acquired on a FlowSight. Samples were analyzed to identify nonclassical (CD14+/16+) and classical (CD14+/16-) monocytes. We measured monocyte concentration, adhesion molecule expression, CD36 expression, and oxidized LDL (oxLDL) endocytosis for preprandial 1, 3, and 5 h postprandial. RESULTS: Consuming a high-fat meal caused increases in oxLDL uptake, adhesion molecule expression, and CD36 expression in both classical and nonclassical monocytes, with the nonclassical monocytes responding with larger increases than the classical monocytes. CONCLUSION: These results suggest that consumption of a high-fat meal increased the potential of monocytes to become foam cells, and implicates nonclassical monocytes as having greater potential than classical monocytes to become foam cells. © 2016 International Clinical Cytometry Society.

Consumption of a high-fat breakfast on consecutive days alters preclinical biomarkers for atherosclerosis.

BACKGROUND/OBJECTIVES: Recent research has speculated that the risk of developing atherosclerosis is due to the accumulation of the effects of daily diet choices. The purpose of this study was to examine which of our previously identified preclinical disease risk biomarkers were further elevated when consuming a high-fat (644±50 kcal; 100% recommended dietary allowance for fat), high-calorie (1118±100 kcal; 70% daily caloric needs) breakfast on consecutive days. Young, normal weight females (N=7) participated in this study. SUBJECTS/METHODS: Blood samples were taken premeal and hourly for 5-h postprandial. Serum biomarkers (C-peptide, eotaxin, gastric inhibitory polypeptide, granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte colony-stimulating factor (GM-CSF), insulin, leptin, monocyte chemoattractant protein 1, pancreatic polypeptide (PPY) and tumor necrosis factor-α), monocyte concentration, and adhesion molecule expression (CD11a, CD18 and CD54) were measured. Area under the curve was calculated for each outcome variable as a function of day and data were analyzed for significance. RESULTS: We found significant (P<0.05) increases on Day 2 for: GM-CSF (+47%; P=0.041), G-CSF (+31%; P=0.012), PPY (+51%; P=0.049), total monocyte (+110%; P=0.043), pro-inflammatory (PI) monocyte (+60%; P=0.012), PI monocyte CD18 (+960%; P=0.003), PI monocyte CD11a (+230%; P=0.006), and PI monocyte CD54 (+208%; P=0.015). CONCLUSIONS: To our knowledge, the present study is the first to report changes in selected biomarkers and monocytes following eating a high-fat, high-calorie breakfast on consecutive days in humans. More research is needed to determine how transient the observed changes are and what the long-term implications for disease risk are.

Considerations to maximize fat mass gain in a mouse model of diet-induced weight gain.

Mouse experimental models of diet-induced weight gain are commonly used as analogs to human obesity; however, a wide variety of feeding methods have been used and the most effective way to maximize weight gain is not known. Maximizing weight gain may allow for a reduction in the number of animals required for a given experiment. The purpose of this study was how to cause the greatest amount of weight gain in CD-1 mice by modifying the composition and source of their diet. To accomplish this goal, we completed two experiments: (1) Effect of dietary macronutrient fat intake (60% (HF60), 45% (HF45), 30% (HF30), or 13.5% (CON) fat diet for 18 weeks); and (2) Effect of 1:1 mixed HF60 and CON diets. Outcome measures included food intake, body mass, and body composition, which were measured bi-weekly and statistically analyzed using a repeated measures analysis of variance (RM-ANOVA). In Experiment 1, the greatest increase in body and fat mass was observed in HF60 (36%) and HF45 (29%) compared with HF30 and CON (P < 0.05). In Experiment 2, HF + stock diet (SK) gained 25% more body mass and 70% more fat mass than HF (P < 0.05). Collectively, these findings suggest that using a high-fat based diet (>45% calories from fat), mixed with a stock diet, results in substantially more weight gain over a similar period, of time, which would allow an investigator to use ~40% fewer animals in their experimental model.

Baker's yeast ß-glucan supplementation increases monocytes and cytokines post-exercise: implications for infection risk?

Strenuous aerobic exercise is known to weaken the immune system, and while many nutritional supplements have been proposed to boost post-exercise immunity, few are known to be effective. The purpose of the present study was to evaluate whether 10 d of supplementation with a defined source of baker's yeast ß-glucan (BG, Wellmune WGP®) could minimise post-exercise immunosuppression. Recreationally active men and women (n 60) completed two 10 d trial conditions using a cross-over design with a 7 d washout period: placebo (rice flour) and baker's yeast BG (250 mg/d of ß-1,3/1,6-glucans derived from Saccharomyces cerevisiae) before a bout of cycling (49 ± 6 min) in a hot (38 ± 2°C), humid (45 ± 2 % relative humidity) environment. Blood was collected at baseline (before supplement), pre- (PRE), post- (POST) and 2 h (2H) post-exercise. Total and subset monocyte concentration was measured by four-colour flow cytometry. Plasma cytokine levels and lipopolysaccharide (LPS)-stimulated cytokine production were measured using separate multiplex assays. Total (CD14⁺) and pro-inflammatory monocyte concentrations (CD14⁺/CD16⁺) were significantly greater at POST and 2H (P<0·05) with BG supplementation. BG supplementation boosted LPS-stimulated production of IL-2, IL-4, IL-5 and interferon-γ (IFN-γ) at PRE and POST (P<0·05). Plasma IL-4, IL-5 and IFN-γ concentrations were greater at 2H following BG supplementation. It appears that 10 d of supplementation with BG increased the potential of blood leucocytes for the production of IL-2, IL-4, IL-5 and IFN-γ. The key findings of the present study demonstrate that BG may have potential to alter immunity following a strenuous exercise session.

Mouse blood monocytes: standardizing their identification and analysis using CD115.

Monocytes have been used to assess immune dysfunction and disease. While mouse models are a useful longitudinal analog, few researchers have assessed changes in mouse monocytes. The purpose of this study was to provide recommendations for the sample processing and flow cytometric analysis of mouse blood monocytes. Blood was drawn in a non-lethal manner from CD-1 male mice to be used in three experiments. Experiment 1 compared commonly used mouse monocyte markers. Experiment 2 compared the stability of CD115 expression after immediate (0h) and delayed (2 and 4h) processing following blood collection under various experimental conditions (laser strength, anticoagulant, and storage temp.). Experiment 3 compared the consistency of CD115(+) monocyte and subset concentrations using decreasing (40, 20, 10 and 5µL) volumes of blood. In experiment 1, >95% of CD115(+) events co-expressed CD11b; >85% co-expressed CD14. 70% of CD14(+) and 50% of CD11b(+) events co-expressed CD115. In experiment 2, CD115 expression decreased by 33% between 0 and 4h when stored at room temperature. Blood treated with EDTA and refrigerated maintained CD115 stability. In experiment 3, calculated concentrations for total monocyte events varied by <10% when 40, 20 and 10µL of blood were stained. While CD115 staining provides the most distinct monocyte population, it is important to treat blood with EDTA and refrigerate if sample processing will be delayed over 2h. Collectively, the findings of the present study outline important considerations that must be addressed when examining mouse monocytes in small, non-lethal blood samples.

Resistive exercise blunts LPS-stimulated TNF-alpha and Il-1 beta.

To examine the influence of acute resistive exercise and "hormone status" on cytokine profile, 35 postmenopausal women (72 +/- 6.2 yr) underwent a moderate-high-intensity resistive exercise bout or rested. There were 4 groups: no hormone replacement (NHR, n = 9), hormone replacement (HRT, n = 12), selective estrogen receptor modulator (SER, n = 7), or resting control (no hormone replacement, CON, n = 7). NHR, HRT, and SER exercised (3 sets, 10 exercises @ 80 % 1RM). Blood was collected pre-exercise (PR), postexercise (PO), and two hours (2H) postexercise (same times for CON). Blood was diluted 1 : 10 in culture medium and incubated (37 degrees C, 5 % CO2, 24 h) with lipopolysaccharide (LPS, 25 microg . ml (-1)). Serum and supernatant from LPS-stimulated blood were analyzed for IL-6, IL-1 beta, and TNF-alpha using ELISA. Resistive exercise increased PO serum IL-6, and PO LPS-stimulated IL-6 and IL-1 beta in the exercise groups (HRT, NHR, SER collapsed; EX, n = 28). LPS-stimulated IL-1 beta remained elevated at 2H in EX and was significantly higher than PR in CON at 2H. Expressed per monocyte, EX had significantly lower IL-1 beta and TNF-alpha LPS-stimulated production at PO and 2H compared to CON, indicating an exercise-induced blunting of an apparent diurnal response on cytokine production. In postmenopausal women, acute resistive exercise increased circulating IL-6, but reversed an apparent diurnal increase in LPS-stimulated IL-1 beta and TNF-alpha production with no influence of hormone replacement or raloxifene.

Measurement of body composition changes with weight loss in postmenopausal women: comparison of methods.

BACKGROUND: The accurate measurement of body composition changes is important when evaluating the efficacy of medical nutrition therapy and weight management programs, yet is not well documented in older women. OBJECTIVE: We compared methods of estimating energy-restriction-induced body composition changes in postmenopausal women. DESIGN: 27 women (59 +/- 8 y; BMI 29.0 +/- 2.9 kg/m2; mean +/- SD) completed a 9-wk energy restriction period (5233 kJ/d, (1250 kcal/d)). Changes in % body fat (delta%BF), fat mass (deltaFM), and fatfree mass (deltaFFM) were measured by hydrostatic weighing (HW), air-displacement plethysmography (ADP), dual-energy x-ray absorptiometry (DXA), and deuterium oxide dilution (D2O). The Baumgartner et al. (Am J Clin Nutr 53:1345-1353, 1991) four-compartment (4C) model with body volume from HW was the criterion method. The 4C model with body volume from ADP was also compared. Regression equations were developed based on 4CHW (dependent variable) utilizing results of change (POST-PRE) for each method. RESULTS: The women lost 6.8 +/- 3.2 kg; 9% of baseline weight. Based on 4CHW, the body composition changes were -2.4 +/- 4.5 delta%BF, -4.7 +/- 3.3 kg deltaFM, and -2.6 +/- 4.4 kg deltaFFM. No differences were detected by ANOVA for delta%BF, deltaFM, and deltaFFM among 4CHW, HW, ADP, DXA, D2O, and 4CADP. Bland-Altman limits of agreement showed differences between methods that ranged from 14.5 to -14.1 delta%BF, 7.8 to -8.1 kg deltaFM, and 7.5 to -8.4 kg deltaFFM for individuals. A bias was shown with 4CADP overestimating delta%BF (1.4 %) and FM (0.6 kg) and underestimating deltaFFM (-1.2 kg) compared to 4CHW. The regression model was acceptable for %BF (4CADP, 2CHW, and 2CD2O); FM and FFM (4CADP, 3CDXA, 2CHW, and 2CD2O), but not for other estimates of %BF, FM, FFM. CONCLUSIONS: These body composition assessment methods may be used interchangeably to quantify changes in % body fat, fat mass, and fat-free mass with weight loss in groups of postmenopausal women. 4CADP overestimates delta%BF and underestimates deltaFFM. When utilizing one of these comparison methods (4CADP, 3CDXA, 2CHW, 2CD2O) to quantify changes in fat mass and fat-free mass for an individual postmenopausal woman, regression equations may be used to relate the data to 4CHW.

The effect of pre-exercise cooling on high intensity running performance in the heat.

The purpose of this study was to determine the effect of pre-exercise cooling on high intensity, moderate duration running performance and thermoregulatory responses in a hot environment (38 degrees C, 40 %RH). On separate days, 11 male subjects completed two treadmill runs to exhaustion at 100% of maximal aerobic power with (CL) and without (CT) pre-exercise cooling. Cooling consisted of 20 min of standing rest in a 22 degrees C environment with fan cooling (4.0 m x sec -1) and water spraying (50 ml x min -1) applied to both anterior and posterior body surfaces. Core temperature (T(c)) was determined with an esophageal T(es) probe, and skin temperatures (T(sk)) were measured using surface thermistors positioned at four sites. Finger prick blood samples were taken before and after exercise for the determination of blood lactate. Heart rates and ratings of thermal sensations and comfort were also recorded. Time to exhaustion was significantly shorter in the CL condition (368.9 +/- 56.2) compared to the CT condition (398.8 +/- 55.5 sec). Peak T(es) (37.51 +/- 0.57 vs. 38.56 +/- 0.30 degrees C for CL and CT, respectively), T(sk) (34.18 +/- 1.22 vs. 36.15 +/- 0.70 degrees C for CL and CT, respectively), rates of heat gain (0.20 +/- 0.05 vs. 0.28 +/- 0.05 degrees C x min -1 for CL and CT, respectively), and net heat storage (238.4 +/- 109.6 vs. 531.9 +/- 78.3 kJ for CL and CT, respectively) were all lower in the CL compared to CT throughout the treadmill runs. There were no differences in lactate accumulation between the two conditions. Based on these data, it can be concluded that pre-exercise cooling influences thermoregulatory responses during high intensity, moderate duration exercise; however, performance is impaired compared to a control trial in which no cooling procedures were employed.