Phenotypic Characterization of Human Monocytes following Macronutrient Intake in Healthy Humans

Abstract

BackgroundThree subsets of human monocytes in circulation have been identified and their characterization is still ill-defined. Although glucose and lipid intakes have been demonstrated to exert pro-inflammatory effects on mononuclear cells (MNCs) of healthy subjects, characterization of monocytes phenotypes following macronutrient (glucose, protein, and lipid) intake in humans remains to be determined.MethodsThirty-six healthy, normal weight volunteers were recruited in the study. Subjects were randomly assigned into three groups, each group consisting of 12 participants. Each group drank equal calories (300 kcal) of either glucose or lipids or whey proteins. Each subject served as his own control by drinking 300 mL of water 1 week before or after the caloric intake. Baseline blood samples were drawn at 0, 1, 2, and 3-h intervals post caloric or water intakes. MNCs were isolated, and the expression levels of different cluster of differentiation (CD) markers (CD86, CD11c, CD169, CD206, CD163, CD36, CD68, CD11b, CD16, and CD14) and IL-6 were measured by RT-qPCR.ResultsEquicaloric intake of either glucose or lipids or whey proteins resulted in different monocyte phenotypes as demonstrated by changes in the expression levels of CD and polarization markers. Whey proteins intake resulted in significant mRNA upregulation in MNCs of CD68 and CD11b at 1, 2, and 3 h post intake while mRNA of IL-6 was significantly inhibited at 1 h. Lipids intake, on the other hand, resulted in mRNA upregulation of CD11b at 2 and 3 h and CD206 at 1, 2, and 3 h. There were no significant changes in the other CD markers measured (CD86, CD163, CD169, CD36, CD16, and CD14) following either whey proteins or lipids intakes. Glucose intake did not alter mRNA expression of any marker tested except CD206 at 3 h.ConclusionMacronutrient intake alters the expression levels of polarization markers in MNCs of human subjects. A distinct population of different monocytes phenotypes may result in human circulation following the intake of different macronutrients. Further studies are required to characterize the immunomodulatory effects of macronutrients intake on monocytes phenotypes and their characteristics in humans.

TLR2 and TLR4 Surface and Gene Expression in White Blood Cells after Fasting and Oral Glucose, Lipid and Protein Challenges: Influence of Obesity and Sex Hormones

“…Of note, after protein ingestion CD36 levels showed no reduction while CD86 strongly decreased, particularly in men. Therefore, the regulatory mechanisms influencing their postprandial expression may be differently modulated, at least for proteins, as has been recently described for other surface markers [32]. This latter study did not report significant changes of CD36 and CD86 gene expression after macronutrient intake, nevertheless such work only included younger and lean men and its lipid and protein loads differed from ours in macronutrient source and composition [32].…”

“…Therefore, the regulatory mechanisms influencing their postprandial expression may be differently modulated, at least for proteins, as has been recently described for other surface markers [32]. This latter study did not report significant changes of CD36 and CD86 gene expression after macronutrient intake, nevertheless such work only included younger and lean men and its lipid and protein loads differed from ours in macronutrient source and composition [32]. As for TLR, we hypothesized that the decreased surface expression following macronutrient ingestion may account for a physiologic compensatory mechanism aiming to avoid an exaggerated inflammatory response.…”

“…Previous studies have evaluated the in vitro effects of hyperglycemic conditions and free fatty acid exposition in cells from diverse origin [27]. However, literature regarding the separate influences of isolated macronutrient loads in vivo, particularly proteins, is relatively scarce [28][29][30][31][32].…”

Ophiocephalus striatus Extract Supplementation Decreases Serum IL-6 Levels in Older People with Sarcopenia—A Single-Center Experience

“…Ophiocephalus striatus , commonly known as snakehead fish, is notably rich in essential amino acids, particularly albumin, which has been associated with immune system enhancement that can lead to IL-6 reduction [ 34 ]. Previous studies have highlighted the role of protein intake in inhibiting IL-6 expression, indicating a possible correlation between protein consumption and IL-6 regulation [ 35 ]. Moreover, snakehead fish contains high levels of protein and albumin, which are vital for reducing inflammation [ 36 ].…”

<p>Differential Expression of Human N-Alpha-Acetyltransferase 40 (hNAA40), Nicotinamide Phosphoribosyltransferase (NAMPT) and Sirtuin-1 (SIRT-1) Pathway in Obesity and T2DM: Modulation by Metformin and Macronutrient Intake</p>

“…Whey proteins intake induced high levels of insulin secretion that persisted for more than 3 hrs. 24 This was associated with a lack of hNAA40 expression level changes and inhibition of NAMPT at 3 hrs. Further studies are needed to examine the insulin modulatory effect of this pathway which may play a role in inflammaging and age-related inflammatory conditions.…”