Cholesterol in the Cell Membrane-An Emerging Player in Atherogenesis.

Membrane cholesterol is essential for cell membrane properties, just as serum cholesterol is important for the transport of molecules between organs. This review focuses on cholesterol transport between lipoproteins and lipid rafts on the surface of macrophages. Recent studies exploring this mechanism and recognition of the central dogma-the key role of macrophages in cardiovascular disease-have led to the notion that this transport mechanism plays a major role in the pathogenesis of atherosclerosis. The exact molecular mechanism of this transport remains unclear. Future research will improve our understanding of the molecular and cellular bases of lipid raft-associated cholesterol transport.

The Truth About Fish (Oil) in the Treatment of Dyslipidemia.

PURPOSE OF REVIEW: To discuss the effect of fish oils on dyslipidemias and associated disorders. RECENT FINDINGS: The most important lipid effect of fish oils is reducing plasma triglycerides and the main potential protection against cardiovascular events is very probably mediated also through other mechanisms including anti-inflammatory ones. The best results are available for omega-3 fatty acids, namely, eicosapentaenoic acid. Less evidence is available for the impact of ω-3 fatty acids on liver steatosis/steatohepatitis and acute pancreatitis. In addition, particular fish oils have variable content of saturated and unsaturated fatty acids with different anti- or pro-oxidative potential, and the suboptimal ratio of these compounds could attenuate or abolish their beneficial properties. Fish products with optimal proportion of fatty acids, particularly high content of eicosapentaenoic acid, could be recommended to patients with dyslipidemias, especially to those at high risk for cardiovascular disease; less evidence is available for liver disease and acute pancreatitis.

Hypertriglyceridemia and atherosclerosis risk.

The history of studying hypertriglyceridemia as a risk factor for atherosclerosis has been going on for a half a century. The significance of this parameter as measured in fasting state is not entirely clear, since the statistical significance between triglyceride concentration and cardiovascular risk is lost after adjustment to HDL-cholesterol concentration. Remnant particles of chylomicrons and very low density lipoproteins measured postprandially appear to be responsible for the risk associated with hypertriglyceridemia. As the concentration of non-fasting triglycerides increases, the risk of myocardial infarction increases gradually up to five times.

Inflammation and atherosclerosis.

Although current treatment of hypertension and hypercholesterolemia is most effective, cardiovascular mortality still remains at 50 % in industrialized countries. This could be explained by the rather high contribution of the inflammatory process to atherogenesis development. Use of high-sensitivity C-reactive protein (hsCRP) determination in several large epidemiological studies has made it possible to document increased risk of myocardial infarction in individuals with slightly increased hsCRP concentrations, which could thus serve as a discriminatory factor in cardiovascular disease risk assessment. However, the situation is not that simple since hsCRP concentrations correlate significantly with BMI, age and smoking as major cardiovascular risk factors. Increased proportion of pro-inflammatory macrophages in visceral adipose tissue has also been shown to rise with BMI, age (differently in men and women) and non-HDL-cholesterol levels. It has been suggested that the pro-inflammatory status induced by a higher proportion of pro-inflammatory macrophages in visceral adipose tissue acts synergistically in atherogenesis development. Key words: atherosclerosis - cardiovascular disease - inflammation.

The relationship between non-HDL cholesterol and macrophage phenotypes in human adipose tissue.

Data from experimental animal models and in vitro studies suggest that both hyperlipoproteinemia and obesity predispose to development of proinflammatory pathways of macrophages within adipose tissue. The aim of this study was to analyze whether non-HDL cholesterol concentration in healthy living kidney donors (LKDs) is related to the number and phenotype of proinflammatory macrophages in visceral and subcutaneous adipose tissue. Adipose tissue samples were collected by cleansing the kidney grafts of LKDs obtained peroperatively. The stromal vascular fractions of these tissues were analyzed by flow cytometry. Proinflammatory macrophages were defined as CD14+ cells coexpressing CD16+ and high-expression CD36 as well (CD14+CD16+CD36+++), while CD16 negativity and CD163 positivity identified alternatively stimulated, anti-inflammatory macrophages. Non-HDL cholesterol concentration positively correlated to proinflammatory macrophages within visceral adipose tissue, with increased strength with more precise phenotype determination. On the contrary, the proportion of alternatively stimulated macrophages correlated negatively with non-HDL cholesterol. The present study suggests a relationship of non-HDL cholesterol concentration to the number and phenotype proportion of macrophages in visceral adipose tissue of healthy humans.

Characterisation and comparison of adipose tissue macrophages from human subcutaneous, visceral and perivascular adipose tissue.

BACKGROUND AND AIMS: Macrophages play important roles in adipose tissue inflammation and its consequences. Unfortunately, a detailed description of the macrophage phenotypes in different human adipose tissues is not available. SUBJECTS AND METHODS: Subcutaneous, visceral and perivascular adipose tissues were obtained from 52 living kidney donors during live donor nephrectomy. Stromal vascular fractions were isolated, and the macrophage phenotypes were analyzed by flow cytometry using surface markers (CD14, CD16, CD36, and CD163). RESULTS: In addition to CD16 positivity, pro-inflammatory macrophages also display high scavenger receptor CD36 expression. The great majority of CD16 negative macrophages express the anti-inflammatory CD163 marker. The presence of pro-inflammatory macrophages was almost twice as high in visceral (p < 0.0001) and perivascular (p < 0.0001) adipose tissues than in subcutaneous tissue. This difference was substantially more pronounced in the postmenopausal women subgroup, consequentlly, the total difference was driven by this subgroup. CONCLUSION: We obtained detailed information about M1 and M2 macrophage phenotypes in human adipose tissue. The visceral and perivascular adipose tissues had substantially higher pro-inflammatory characteristics than the subcutaneous tissue. The higher proportion of pro-inflammatory macrophages in the visceral adipose tissue of postmenopausal women might be related to an increased cardiovascular risk.

Longitudinal Trends in Severe Dyslipidemia in the Czech Population: The Czech MONICA and Czech Post-MONICA Study.

Background: Severe hypercholesterolemia is associated with an increase in the risk of developing atherosclerotic cardiovascular disease. The aim of this analysis was to assess longitudinal trends in severe dyslipidemia (defined as total cholesterol > 8 mmol/L or LDL-cholesterol > 5 mmol/L) in a representative population sample of the Czech Republic and to analyze the longitudinal trends in the basic characteristics of individuals with severe dyslipidemia. Methods: Seven independent cross-sectional surveys were organized in the Czech Republic to screen for major cardiovascular risk factors (from 1985 to 2015-2018). A total of 20,443 randomly selected individuals aged 25-64 years were examined. Results: The overall prevalence of severe dyslipidemia was 6.6%, with a significant downward trend from the fifth survey onwards (2000/2001). Over the study period of 30+ years, the individuals with severe dyslipidemia became older, increased in BMI, and did not change their smoking habits. Total cholesterol and non-HDL-cholesterol decreased significantly in both sexes throughout the duration of the study. Conclusions: Despite a significant improvement in lipids in the Czech Republic from 1985, substantially contributing to the decline in cardiovascular mortality, the number of individuals with severe dyslipidemia remained high, and in most cases, they were newly detected during our screening examinations and were thus untreated.

HDL and apolipoprotein A1 concentrations as markers of cholesterol efflux in middle-aged women: interaction with smoking.

OBJECTIVES: It has been demonstrated that the deleterious effect of smoking on the cardiovascular system is mediated through a decrease in protective HDL cholesterol. In addition, women are more sensitive to the negative effects of smoking, although the exact mechanism underlying this phenomenon is currently unknown. In this study, we evaluated whether smoking habits could modify the association of HDL cholesterol and apolipoprotein A1 (ApoA1) with reverse cholesterol transport (RCT), as measured by cholesterol efflux (CHE), in middle-aged women. DESIGN: The study group consisted of 39 healthy middle-aged women, 21 non-smokers (age 51.8±2.5 years, BMI 25.1±2.8 kg/m2) and 18 smokers (age 50.5±3.2 years, BMI 24.8±3.5 kg/m2). In addition to all traditional cardiovascular risk factors, CHE from macrophages, labelled during a 48-hour incubation in a medium containing [14C] cholesterol, to plasma acceptors in study subjects was established as a marker of reverse cholesterol transport. RESULTS: CHE was significantly higher in non-smokers than in smokers (14.22±1.75% vs. 13.17±1.33%; p<0.05). Smoking habit had no effect on the association of HDL with ApoA1 or HDL with CHE. However, in contrast to the strong association of ApoA1 with CHE in non-smokers (r=0.62; p<0.01), no such strong association was found in smokers (r=0.38; n.s.). Main findings and conclusion: Based on our results, smoking can alter ApoA1-mediated reverse cholesterol transport in women.

Links between macrophages in perivascular adipose tissue and arterial wall: a role in atherosclerosis initiation?

BACKGROUND: Inflammation of adipose tissue in relation to atherosclerosis is currently widely studied in patients with advanced disease. However, data regarding polarization of adipose tissue and arterial wall macrophages and their mutual link in the early stages of atherosclerosis are scarce. The main aim of this cross-sectional study was to characterize macrophage subpopulations in arterial wall and adjacent adipose tissue; and to determine links between different subpopulations in a relatively healthy population living kidney donors. METHODS: The presence of cardiovascular risk factors was established in 68 living kidney donors. Macrophage polarization was analyzed by flow cytometry and confirmed by RT-PCR in samples of visceral adipose tissue, renal artery and adjacent perivascular adipose tissue collected during hand-assisted retroperitoneoscopic nephrectomy. RESULTS: CD14+CD16+CD36high macrophages were found only in adipose tissues and were strongly positively associated with several cardiovascular risk factors. The CD14+CD16+CD36low subpopulation was positively associated with the presence of several cardiovascular risk factors to a lesser extent in all studied tissues. In contrast, the proportion of CD14+CD16-CD36low macrophages was negatively linked to several cardiovascular risk factors and increased in subjects on statin therapy. The proportion of CD14+CD16+CD36low macrophages in perivascular, not visceral adipose tissue was associated with that of both macrophage subtypes in the arterial wall, suggesting a direct link between perivascular adipose tissue and the arterial wall. CONCLUSIONS: We confirmed the association of three macrophage subtypes in adipose tissue and arterial wall to the studied cardiovascular risk factors. Macrophage polarization in perivascular, but not visceral adipose tissue was linked to macrophage polarization in the arterial wall.

Rapid Drop in Coronary Heart Disease Mortality in Czech Male Population-What Was Actually behind It?

The high mortality of coronary heart disease (CHD) among Czech men-one of the highest worldwide-began to decline in 1991 soon after the abolition of government subsidies to all foodstuffs rich in animal fat. As participants in the WHO MONICA Project, we were able to analyze the CHD risk factors just before and after this major economic change. We had previously documented that the originally subsidized prices decreased animal fat consumption and consequently non-HDL cholesterol concentrations in the population. By the early 1990s, no progress had been made in the treatment of acute myocardial infarction, statins were unavailable as was not the currently more effective antihypertensive therapy. Our recent research proved a close relationship between cholesterolemia and proinflammatory macrophages in adipose tissue and accelerated macrophage polarization with increased palmitate and palmitoleate contents in cell membrane phospholipids. By contrast, the proportion of proinflammatory macrophages decreases with increasing presence of n-3 fatty acids in the cell membrane. The combination of non-HDL cholesterol drop and a decreased proportion of proinflammatory macrophages due to replacement of alimentary fat decreased CHD mortality immediately.

Dietary intake reports fidelity--fact or fiction?

OBJECTIVES: Bias is common in the assessment of self-reported dietary intake and physical activity. Little is known about the reasons for this underreporting, which is obtained even from rural individuals and lean subjects. MATERIAL AND METHODS: Healthy volunteers (16 males, aged 18-55 years) were given two different full diets (high and low in saturated fat), each for a period of 4 weeks. RESULTS: The subjects were able to provide a report of their dietary intake with relatively high accuracy (68.4%) on day one. Accuracy declined on day two (64.2%), and on day three, the reporting accuracy was only 55.0% (p<0.05). Interestingly, on day one, individuals were more precise (p<0.05) in their dietary reports if they had consumed an unhealthy diet high in saturated fat (72.5%) than a healthy diet high in unsaturated fat (64.4%). The most frequently omitted items were fruits and vegetables. The non-reporting of food items consumed is very high, even in the short term, and individuals tend to remember unhealthy items better. CONCLUSIONS: Our pilot study showed that the inaccuracy of self-reported data includes not only the underestimation of energy intake (portion size) but also inaccurate qualitative data.

An AHSG gene variant modulates basal metabolic rate and body composition development after a short-time lifestyle intervention.

OBJECTIVES: The AHSG (alpha2 Heremans-Schmid glycoprotein) gene is suggested to be important for the regulation of body fat and insulin sensitivity. Our study aimed to investigate the relationship between the common Thr248Met (rs4917) variant and obesity characteristics after an intervention with overweight females. MATERIAL AND METHODS: We analyzed 105 unrelated overweight/obese nondiabetic Czech adult females (49.0 ± 12.1 years, BMI over 28.6 kg/m2, mean BMI before intervention 32.8 ± 4.1 kg/m2) before and after 10 weeks of lifestyle modification. Biochemical and anthropometrical measurements were performed. The life style modification program consisted of a reduction of energy intake to an age-adjusted optimum and an exercise program (four units per week). The mean weight loss was 3.2 ± 3.5 kg (3.7 ± 4.0%). RESULTS: Thr/Thr homozygotes (N=52) increased lean muscle mass (p<0.05), decreased total body fat (kg) (p<0.005) and increased basal metabolic rate (BMR) per 1 kg body weight (p<0.005) in comparison with the Met carriers (N=52), but an association between BMI decrease and AHSG variants was not found. CONCLUSION: AHSG gene variants modify the effect of physical activity on BMR. Carriers of the Thr248Thr genotype showed a higher benefit from the lifestyle intervention (expressed as changes in body fat, active muscle and basal metabolic rate).

Statins Directly Influence the Polarization of Adipose Tissue Macrophages: A Role in Chronic Inflammation.

Statins represent one of the most widely used classes of drugs in current medicine. In addition to a substantial decrease in atherogenic low density lipoprotein (LDL) particle concentrations, several large trials have documented their potent anti-inflammatory activity. Based on our preliminary data, we showed that statins are able to decrease the proportion of pro-inflammatory macrophages (CD14+16+CD36high) in visceral adipose tissue in humans. In the present study including 118 healthy individuals (living kidney donors), a very close relationship between the pro-inflammatory macrophage proportion and LDL cholesterol levels was found. This was confirmed after adjustment for the most important risk factors. The effect of statins on the proportion of pro-inflammatory macrophages was also confirmed in an experimental model of the Prague hereditary hypercholesterolemia rat. A direct anti-inflammatory effect of fluvastatin on human macrophage polarization in vitro was documented. Based on modifying the LDL cholesterol concentrations, statins are suggested to decrease the cholesterol inflow through the lipid raft of macrophages in adipose tissue and hypercholesterolemia to enhance the pro-inflammatory macrophage phenotype polarization. On the contrary, due to their opposite effect, statins respond with anti-inflammatory activity, affecting the whole organism.

Very low lipoprotein(a) and increased mortality risk after myocardial infarction.

BACKGROUND: Inconclusive data exist on risk associated with Lp(a) in patients after myocardial infarction (MI). Aims of the present study were to evaluate the association of Lp(a) level with total mortality and recurrent cardiovascular events. DESIGN AND METHODS: Single center prospective registry of consecutive patients hospitalized for acute myocardial infarction between June 2017 and June 2020 at a large tertiary cardiac center with available blood samples drawn <24h of admission. RESULTS: Data from 851 consecutive patients hospitalized for MI were evaluated. During the median follow-up of 19 months (interquartile range 10-27), 58 (6.8%) patients died. Nonlinear modelling revealed a U-shaped association between Lp(a) and total mortality risk. Compared to patients with Lp(a) ranging between 10-30 nmol/L and after multivariate adjustment, total mortality risk was increased both in patients with Lp(a)<7 nmol/L (hazard ratio (HR) 4.08, 95% confidence interval (CI) 1.72-9.68) and Lp(a) ≥125 nmol/L (HR 2.92, 95% CI 1.16-7.37), respectively. Similarly, the risk of combined endpoint of acute coronary syndrome recurrence or cardiovascular mortality was increased both in patients with low (sub-HR 2.60, 95% CI 1.33-5.08) and high (sub-HR 2.10, 95% CI 1.00-4.39) Lp(a). Adjustment for heart failure signs at the time of hospitalization weakened the association with total mortality and recurrent cardiovascular events. CONCLUSIONS: In the present analysis, both high and low concentrations of Lp(a) were associated with an increased risk of total mortality and recurrent cardiovascular events after MI. The excess of mortality associated with Lp(a) was partially attributable to more prevalent heart failure.

Immune cells in carotid artery plaques: what can we learn from endarterectomy specimens?

INTRODUCTION: Endarterectomy specimens represent a unique opportunity to study atherosclerosis. This review aims to summarize the recent knowledge of atherogenesis from studies characterizing a cellular composition of carotid endarterectomy specimens. EVIDENCE ACQUISITION: A non-systematic literature review was carried out to summarize recent knowledge regarding ex vivo analysis of carotid artery plaque composition. Upon evaluation of their relevance, and elaborate forward and backward search, 95 articles were included in the review. EVIDENCE SYNTHESIS: Despite the significant advancement of in vivo imaging techniques, the stroke prediction based on carotid artery plaque morphology is not reliable. Besides analyses of plaque morphology, present studies focus on precise characterization of the different immune cell types and elucidation of their role in plaque development. Plaque content analyses revealed the presence of various immune cells in carotid artery plaques. Presence of different immune cells subpopulations can be connected to some undesirable changes in plaque stability. CONCLUSIONS: Since the destabilization of the atherosclerotic plaque is a multifactorial process, a combination of various methods should be used to characterize the unstable plaques more accurately. In this context, studies characterizing plaque content from a cellular point of view could elucidate some processes underlying the plaque progression. Together with morphological evaluation, these analyses could enable more precise assessment of plaque stability.

30-year trends in major cardiovascular risk factors in the Czech population, Czech MONICA and Czech post-MONICA, 1985 - 2016/17.

BACKGROUND: Compared with Western Europe, the decline in cardiovascular (CV) mortality has been delayed in former communist countries in Europe, including the Czech Republic. We have assessed longitudinal trends in major CV risk factors in the Czech Republic from 1985 to 2016/17, covering the transition from the totalitarian regime to democracy. METHODS: There were 7 independent cross-sectional surveys for major CV risk factors conducted in the Czech Republic in the same 6 country districts within the WHO MONICA Project (1985, 1988, 1992) and the Czech post-MONICA study (1997/98, 2000/01, 2007/08 and 2016/2017), including a total of 7,606 males and 8,050 females. The population samples were randomly selected (1%, aged 25-64 years). RESULTS: Over the period of 31/32 years, there was a significant decrease in the prevalence of smoking in males (from 45.0% to 23.9%; p < 0.001) and no change in females. BMI increased only in males. Systolic and diastolic blood pressure decreased significantly in both genders, while the prevalence of hypertension declined only in females. Awareness of hypertension, the proportion of individuals treated by antihypertensive drugs and consequently hypertension control improved in both genders. A substantial decrease in total cholesterol was seen in both sexes (males: from 6.21 ± 1.29 to 5.30 ± 1.05 mmol/L; p < 0.001; females: from 6.18 ± 1.26 to 5.31 ± 1.00 mmol/L; p < 0.001). CONCLUSIONS: The significant improvement in most CV risk factors between 1985 and 2016/17 substantially contributed to the remarkable decrease in CV mortality in the Czech Republic.

Depressive symptoms and levels of C-reactive protein: a population-based study.

BACKGROUND: Depression and depressive symptoms have been repeatedly linked to elevated levels of C-reactive protein (CRP) but questions remain as to the statistical robustness of the association and particularly whether the association between depression and CRP reflects the presence of a chronic disease. METHODS: A random sample of 6,126 men and women aged 45-69 years was examined in a cross-sectional study in seven towns in the Czech Republic. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression (CESD) scale. RESULTS: Center for Epidemiologic Studies Depression score was significantly related to increased levels of CRP in a linear fashion. After controlling for a range of potential confounders, subjects with depressive symptoms (CESD score >or= 16) had CRP concentrations 0.43 mg/l (95% CI 0.16-0.72) higher than those without symptoms. The association remained significant when study sample was restricted to healthy subjects; among individuals who did not report any chronic disease, the difference between those with and without depressive symptoms was 0.44 mg/l (95% CI 0.14-0.74), and among persons who did not visit a doctor in the last 12 months the difference was 1.20 mg/l (95% CI 0.52-1.87). CONCLUSIONS: These results confirm that there is a statistically robust association between depressive symptoms and increased levels of CRP. We did not find evidence that the association is due presence of a chronic condition.

Polarization of Macrophages in Human Adipose Tissue is Related to the Fatty Acid Spectrum in Membrane Phospholipids.

Residential macrophages in adipose tissue play a pivotal role in the development of inflammation not only within this tissue, but also affect the proinflammatory status of the whole body. Data on human adipose tissue inflammation and the role of macrophages are rather scarce. We previously documented that the proportion of proinflammatory macrophages in human adipose tissue correlates closely with non-HDL cholesterol concentrations. We hypothesized that this is due to the identical influence of diet on both parameters and decided to analyze the fatty acid spectrum in cell membrane phospholipids of the same individuals as a parameter of the diet consumed. Proinflammatory and anti-inflammatory macrophages were isolated from human adipose tissue (n = 43) and determined by flow cytometry as CD14+CD16+CD36high and CD14+CD16-CD163+, respectively. The spectrum of fatty acids in phospholipids in the cell membranes of specimens of the same adipose tissue was analyzed, and the proportion of proinflammatory macrophage increased with the proportions of palmitic and palmitoleic acids. Contrariwise, these macrophages decreased with increasing alpha-linolenic acid, total n-3 fatty acids, n-3/n-6 ratio, and eicosatetraenoic acid. A mirror picture was documented for the proportion of anti-inflammatory macrophages. The dietary score, obtained using a food frequency questionnaire, documented a positive relation to proinflammatory macrophages in individuals who consumed predominantly vegetable fat and fish, and individuals who consumed diets based on animal fat without fish and nut consumption. he present data support our hypothesis that macrophage polarization in human visceral adipose tissue is related to fatty acid metabolism, cell membrane composition, and diet consumed. It is suggested that fatty acid metabolism might participate also in inflammation and the risk of developing cardiovascular disease.

The effect of cytokines produced by human adipose tissue on monocyte adhesion to the endothelium.

Visceral adipose tissue (VAT) may play a critical role in atherosclerotic cardiovascular disease. The goal of this study was to determine the effect of human VAT-released pro­inflammatory cytokines on monocyte adhesion to the endothelium. The cytokine effects on monocyte adhesion to the endothelial cells (ECs) were tested using adipose tissue-conditioned media (ATCM) prepared by culturing human VAT. The cytokines concentrations in ATCM, the cytokines expression and adhesion molecules in stimulated ECs were measured. The concentrations of IL-1ß,TNF-α,MCP-1,IL-10,and RANTES measured in ATCM correlated positively with monocyte adhesiveness to ECs. Additionally, ATCM increased the adhesion molecules (ICAM-1, VCAM-1) gene expression. Selective inhibitors highlighted the importance of IL-1ß and TNF-α in the process by a significant decrease in monocyte adhesion compared to ATCM preconditioning without inhibitors. Human VAT significantly increased monocyte adhesion to ECs. It was significantly influenced by IL-1ß, TNF-α, MCP-1, IL-10, and RANTES, with IL-1ß and TNF­α having the strongest impact.

Different acute effects of fructose and glucose administration on hepatic fat content.

BACKGROUND: Diets rich in fat and added sugars (especially fructose) play an important role in the pathogenesis of nonalcoholic liver disease (NAFLD), but there is only limited information on the acute effects of these nutrients on hepatic fat content (HFC). OBJECTIVES: We therefore explored how the administration of high-fat load, glucose, fructose, and combinations thereof affects HFC measured in vivo using proton magnetic resonance spectroscopy (1H-MRS) in healthy subjects. METHODS: Ten healthy nonsteatotic male volunteers (age 38.5 ± 9.6 y, body mass index [BMI, kg/m2] 26.9 ± 2.7) underwent, in random order, 6 experiments, each lasting 8 h, that included: 1) fasting; 2) a high-fat load (150 g of fat [dairy cream] at time 0); 3) glucose (3 doses of 50 g at 0, 2, and 4 h); 4) a high-fat load with glucose; 5) fructose (3 doses of 50 g at 0, 2, and 4 h); and 6) a high-fat load with fructose. HFC was measured using 1H-MRS prior to test meal administration (before time 0) and at 3 and 6 h. Plasma concentrations of triglycerides, nonesterified fatty acids, glucose, and insulin were monitored throughout each experiment. RESULTS: HFC increased to 119 ± 19% (P < 0.05) and 117 ± 17% (P < 0.01) of baseline when subjects consumed a high-fat load alone or a high-fat load with fructose, respectively, but was not affected when glucose was coadministered with a high-fat load. HFC was not affected when subjects had fasted or had consumed repeated doses of fructose. When subjects were administered 3 doses of glucose, HFC dropped to 85 ± 13% (P < 0.05) of baseline. CONCLUSIONS: Our results demonstrate that fructose and glucose have a different immediate impact on HFC in humans in vivo. Clinical trial registry: The study was registered at clinicaltrials.gov and obtained clinicaltrials.gov identifier: NCT03680248.