Postprandial Monocyte Study (PPMS)

Western Human Nutrition Research Center (WHNRC) Postprandial Monocyte Study

The purpose of this research is to determine the role of a type of immune cell in blood, called a non-classical monocytes (NCMs), following consumption of a high-fat meal. Previous studies have found that monocytes are important for blood vessel health. In this study, two different high-fat meals will be used to study the effect of different types of dietary fat on postprandial NCMs. The investigators will characterize NCMs in both fasting conditions and following consumption of two different high-fat meals, and will evaluate whether the type of fat in a meal affects NCMs in blood.

Study Overview

• Status: Recruiting
• Conditions: Inflammation; Nutrition; Immune System
• Intervention / Treatment: Other: High saturated fat challenge meal; Other: High mono unsaturated fat challenge meal

Detailed Description

Monocytes are a heterogeneous population of circulating blood cells that contribute to tissue integrity as well as to innate and adaptive immune defense. There are three well-characterized subsets based on their relative expression of surface antigens, cluster of differentiation 14 (CD14) and cluster of differentiation 16 (CD16). Monocytes originate from myeloid precursors in the bone marrow and enter the circulation as classical monocytes (CLMs). CLMs represent a transient cell population with a diverse differentiation potential. CLMs comprise 80-90% of the circulating blood monocyte pool and remain in circulation for approximately one day before either migrating into tissue to repopulate the tissue resident macrophage population or maturing into non-classical monocytes (NCMs). NCMs comprise only 5-10% of the circulating blood monocyte pool but have a much longer circulating lifespan of approximately 7 days. NCMs exhibit conflicting functions as anti-inflammatory caretakers of vascular tissue and as contributors to the pathogenesis of disease.

Metabolic responses to food consumption influence the risk of cardiometabolic disease. Postprandial glycemia and lipemia modulate vascular health by altering endothelial function and inducing oxidative stress, inflammation, and apoptosis. Consumption of a single high-fat meal increases circulating interleukin 6 (IL-6), enhances expression of monocyte adhesion molecules, reduces flow-mediated dilation, and increases markers of oxidative stress in human subjects. Although NCMs are described as vascular housekeepers with distinct motility and crawling patterns allowing them to actively surveil endothelium and scavenge luminal debris, their role in the postprandial state is currently unknown.

To better understand the function of postprandial NCMs following consumption of a single high-fat mixed macronutrient challenge meal, the investigators propose a study following a crossover design in which participants will consume one of two isocaloric high-fat challenge meals spaced two-weeks apart, a high-saturated fat mixed macronutrient challenge meal or a high-monounsaturated fat mixed macronutrient challenge meal. Blood at fasting and at six hours postprandial will be collected and the proportion of NCMs and their integrin expression will be analyzed by flow cytometry while changes in global gene expression will be measured by RNA-sequencing.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ryan Snodgrass, PhD; Phone Number: 530-754-4838; Email: ryan.snodgrass@usda.gov
• Study Contact Backup: Name: Ellen Bonnel, PhD; Phone Number: 530-752-4184; Email: elbonnel@ucdavis.edu

Study Locations

• United States
  • California
    • Davis, California, United States, 95616
      • Recruiting
      • USDA Western Human Nutrition Research Center
      • Contact: Charles Stephensen, PhD; Phone Number: 530-304-3528; Email: charles.stephensen@usda.gov

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 39 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• BMI 18.5 - 29.9 kg/m²
• have a bank account and social security number or taxpayer identification for financial compensation

Exclusion Criteria:

• Pregnant or lactating women
• Known allergy or hindering intolerance to study meal ingredients
• Systolic blood pressure greater than 140 mmHg or diastolic blood pressure greater than 90 mmHg measured
• Fasting glucose above 105 mg/dL
• Triglycerides above 150 mg/dL
• HDL cholesterol less than 40 mg/dL (men) and 50 mg/dL (women)
• Self-reported history of difficulties with blood drawing procedures including prior fainting or dizziness, or veins assessed as not suitable for four separate venipunctures by licensed phlebotomist
• Diagnosed active chronic diseases for which the individual is currently taking daily medication, including but not limited to Diabetes mellitus, Cardiovascular disease, Cancer, Gastrointestinal disorders, Kidney disease, Liver disease, Bleeding disorders, Asthma, Autoimmune disorders, Hypertension, Osteoporosis
• Recent minor surgery (within 4 wk) or major surgery (within 16 wk)
• History of gastrointestinal surgery, including gastric bypass surgery or resection
• Recent antibiotic therapy (within 4 wk)
• Known gallbladder disease or history of cholecystectomy
• Recent hospitalization (within 4 wk)
• Use of prescription medications at the time of the study that directly affect endpoints of interest (e.g. hyperlipidemia, glycemic control, steroids, statins, anti-inflammatory agents, and over-the-counter weight loss aids)
• Current participation in another research study
• Less than 18 and over 39 years old
• BMI less than 18.5 and above 29.9 kg/m²
• Has HIV/AIDS or another disease that affects the immune system
• Unable to fast for 12 hours
• Gives regular blood donations and is unwilling to stop during the study
• Has monocytosis (>0.8 x 10³/microliter) or other abnormalities in hematologic parameters based on a screening complete blood count (CBC) with differential

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High saturated fat challenge meal followed by high mono-unsaturated fat challenge meal; High saturated fat mixed macronutrient challenge meal with palm oil followed by high mono-unsaturated fat mixed macronutrient challenge meal with olive oil two weeks later	Other: High saturated fat challenge meal; High saturated fat challenge meal made with palm oil; Other: High mono unsaturated fat challenge meal; High mono unsaturated fat challenge meal made with olive oil
Experimental: High mono-unsaturated fat challenge meal followed by high saturated fat challenge meal; High mono-unsaturated fat mixed macronutrient challenge meal with olive oil followed by high saturated fat mixed macronutrient challenge meal with palm oil two weeks later	Other: High saturated fat challenge meal; High saturated fat challenge meal made with palm oil; Other: High mono unsaturated fat challenge meal; High mono unsaturated fat challenge meal made with olive oil

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Monocyte subsets	Monocyte subsets will be analyzed using flow cytometry. Subset analysis will be performed by labeling immune cells with anti-cluster of differentiation antigen 45 (anti-CD45), cluster of differentiation antigen 91 (anti-CD91), anti-CD14, and anti-CD16 fluorescently labeled antibodies.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in expression of very late antigen-4	Monocyte adhesion molecule expression of very late antigen-4 (VLA-4) will be assessed using flow cytometry.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in expression of C-X3-C motif chemokine receptor 1	Monocyte adhesion molecule expression of C-X3-C motif chemokine receptor 1 (CX3CR1) will be assessed using flow cytometry.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in expression of Notch2	Monocyte adhesion molecule expression of Notch2 will be assessed using flow cytometry.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in expression of colony stimulating factor 1 receptor	Monocyte adhesion molecule expression of colony stimulating factor 1 receptor (CSFR1) will be assessed using flow cytometry.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in expression of scavenger receptor class B, member 3	Monocyte adhesion molecule expression of scavenger receptor class B, member 3 (CD36) will be assessed using flow cytometry.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in intensity of filamentous-actin	Filamentous-actin (F-actin) intensity will be assessed using phalloidin.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in white blood cell count	White blood cell (WBC) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in lymphocyte count	Lymphocyte (LY) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in monocyte count	Monocyte (MO) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in change in neutrophil granulocyte count	Neutrophil granulocyte (NE) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in eosinophil count	Eosinophil (EO) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in basophil count	Basophil (BA) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in red blood cell count	Red blood cell (RBC) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in hemoglobin	Hemoglobin (HGB) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in hematocrit	Hematocrit (HCT) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in mean corpuscular volume	Mean corpuscular volume (MCV) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in mean corpuscular hemoglobin	Mean corpuscular hemoglobin (MCH) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in mean corpuscular hemoglobin concentration	Mean corpuscular hemoglobin concentration (MCHC) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in red blood cell distribution width	Red blood cell distribution width (RDW) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in red blood cell distribution width standard deviation	Red blood cell distribution width standard deviation (RDW-SD) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in platelet count	Platelet (PLT) count will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in mean platelet volume	Mean platelet volume (MPV) will be measured by a DxH 520 Hematology analyzer.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in soluble cluster of differentiation antigen 146	Endothelial activation including soluble cluster of differentiation antigen 146 (CD146) will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in CD45 gene expression	Transcriptional changes in non-classical and classical monocytes will be measured by RNA-sequencing following the isolation of non-classical monocytes from peripheral blood by fluorescence-activated cell sorting (FACS) using anti-CD45 fluorescently labeled antibodies.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in CD91 gene expression	Transcriptional changes in non-classical and classical monocytes will be measured by RNA-sequencing following the isolation of non-classical monocytes from peripheral blood by fluorescence-activated cell sorting (FACS) using anti-CD91 fluorescently labeled antibodies.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in CD14 gene expression	Transcriptional changes in non-classical and classical monocytes will be measured by RNA-sequencing following the isolation of non-classical monocytes from peripheral blood by fluorescence-activated cell sorting (FACS) using anti-CD14 fluorescently labeled antibodies.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in CD16 gene expression	Transcriptional changes in non-classical and classical monocytes will be measured by RNA-sequencing following the isolation of non-classical monocytes from peripheral blood by fluorescence-activated cell sorting (FACS) using anti-CD16 fluorescently labeled antibodies.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of interleukin-6	Plasma markers of systemic inflammation including interleukin-6 will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of interleukin-8	Plasma markers of systemic inflammation including interleukin-8 will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of C-reactive protein	Acute phase reactants including C-reactive protein (CRP) will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of serum amyloid A	Acute phase reactants including serum amyloid A (SAA) will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of chemokine ligand 2	Chemokines including chemokine ligand 2 will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of 8-isoprostane F2alpha	Plasma markers of oxidative stress including 8-isoprostane F2alpha will be measured by ELISA.	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of triglycerides	Lipid-related markers including triglycerides will be measured by auto-analyzer, Cobas Integra 400+ instrument	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of total cholesterol	Lipid-related markers including total cholesterol will be measured by auto-analyzer, Cobas Integra 400+ instrument	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of HDL-cholesterol	Lipid-related markers including HDL-cholesterol (HDL-C) will be measured by auto-analyzer, Cobas Integra 400+ instrument	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of LDL-cholesterol	Lipid-related markers including LDL-cholesterol (LDL-C) will be measured by auto-analyzer, Cobas Integra 400+ instrument	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days
Change in levels of glucose	Plasma glucose will be measured by auto-analyzer, Cobas Integra 400+ instrument	Measured from samples taken at 0 hours (fasting) and 6 hours (postprandial) on 2 test days

Collaborators and Investigators

• Sponsor: USDA, Western Human Nutrition Research Center
• Investigators: Principal Investigator: Ryan Snodgrass, PhD, USDA, Western Human Nutrition Research Center

Study record dates

Study Major Dates

• Study Start (Actual): November 14, 2023
• Primary Completion (Estimated): January 1, 2025
• Study Completion (Estimated): January 1, 2025

Study Registration Dates

• First Submitted: March 15, 2023
• First Submitted That Met QC Criteria: March 29, 2023
• First Posted (Actual): March 31, 2023

Study Record Updates

• Last Update Posted (Estimated): November 20, 2023
• Last Update Submitted That Met QC Criteria: November 16, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Keywords: postprandial; monocyte; nonclassical monocytes
• Additional Relevant MeSH Terms: Pathologic Processes; Inflammation
• Other Study ID Numbers: 1999385

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No