The Genetic, Protein, and Lipid Basis of Variation in Cholesterol Efflux

The rationale of this research is that deep phenotyping of individuals at the extremes of cholesterol efflux will identify key determinants of efflux that are potential novel therapeutic targets to prevent or reverse Atherosclerotic Cardiovascular Disease (ASCVD). The investigators propose to carry out the objective by studying participants at extreme low and high cholesterol efflux identified from the investigator's study in the population-based Dallas Heart Study by accomplishing the following aims: 1) determine the heritability of and genomic factors associated with cholesterol efflux by establishing a family pedigree of extreme low and high efflux and sequencing candidate genes involved in HDL metabolism; and 2) identify the protein and lipid signature of extreme low and high cholesterol efflux in a sex- and ethnicity-specific manner using mass spectroscopy and ELISA in FPLC-derived fractions. The investigators expect to identify genetic variants and sex- and ethnicity-specific combinations of proteins and lipids in participants with extreme low and high efflux that may lead to novel ways to modulate efflux. This proposal leverages a well-phenotyped population-based study to characterize the gene-protein-lipid signature of 1) extremes of cholesterol efflux in a sex- and ethnicity-specific manner. Successful completion of these aims will have immediate and direct impact on the use of cholesterol efflux as a clinically relevant biomarker of therapeutic benefit and are necessary for the clinical development of appropriate new targets for manipulation of the key atheroprotective function of cholesterol efflux to reduce ASCVD.

Study Overview

• Status: Completed
• Conditions: Lipid Metabolism Disorders

Detailed Description

The mechanisms that underlie variation in cholesterol efflux are unknown. There is a critical need to identify factors that regulate cholesterol efflux to effectively advance the clinical development of cholesterol efflux as both a risk prediction marker and as a target of therapy. The investigator's long-term goal is to determine whether modulating cholesterol efflux prevents or reverses cardiovascular disease. The overall objective of this study is to systematically create a family pedigree and biobank repository of blood and DNA from participants from the Dallas Heart Study with extreme low or high cholesterol efflux, with the specific aims of : 1) determining the heritability of and genomic factors associated with cholesterol efflux, and 2) identifying the protein and lipid signature of extreme low and high cholesterol efflux in a sex- and ethnicity-specific manner. The investigator's central hypothesis is that a combination of genetic variation in lipid transporters as well as proteins and lipids will be most strongly correlated with variation in efflux.

DHS probands and their relatives (parents, siblings, adult children, grandparents, aunts/uncles, cousins) with extreme low or high cholesterol efflux will be recruited to establish a prospective family pedigree cohort and understand the heritability of extreme cholesterol efflux. Investigators will collect the following information from all participants: demographics, health history, lifestyle measures, and medications. Blood will be collected on-site by venipuncture and plasma, serum, and cells will be stored at -80o Celsius. All efflux measurements will be completed in the investigator's laboratory.

• Study Type: Observational
• Enrollment (Actual): 86

Contacts and Locations

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75390
      • UT Southwestern Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Participants from the Dallas Heart Study (DHS) with extreme low or high cholesterol efflux will be recruited in this study. DHS is a multi-ethnic, population based probability sample of Dallas County designed to define the social and the biological variables contributing to ethnic differences in cardiovascular health at the community level.

https://www.utsouthwestern.edu/edumedia/edufiles/research/center_translational_medicine/dallas_heart_study/dhs-study-overview.pdf

Description

Inclusion Criteria:

• Dallas Heart Study (DHS) Participants who are above or below the sex- and ethnicity-specific 10th and 90th% of cholesterol efflux.
• Family members of the DHS participants are also eligible

Exclusion Criteria:

• HIV
• Cancer
• Autoimmune diseases
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
High Cholesterol Efflux; Dallas Heart Study participants who are above the sex and ethnicity specific 90th % of cholesterol efflux
Low Cholesterol Efflux; Dallas Heart Study participants who are below the sex and ethnicity specific 10th % of cholesterol efflux

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cholesterol Efflux Capacity (CEC)	Cholesterol efflux capacity (CEC) was determined by measuring the efflux of a fluorophore tagged cholesterol, BODIPY (Avanti polar lipids), from J774 murine macrophages (ATCC) to an appropriate acceptor. Efflux is calculated as a unitless measure by using the following formula: [(µCi of 3H-cholesterol in media containing apoB-depleted subject plasma - µCi of 3H-cholesterol in plasma-free media) / (µCi of 3H-cholesterol in media containing apoB-depleted pooled control plasma-µCi of 3H-cholesterol in pooled control plasma-free media)]. Cholesterol efflux capacity is inversely correlated with incidence of cardiovascular events (i.e. higher cholesterol efflux capacity is better for patients).	Baseline
Circulating Metabolite (Glucose) Linked to Variation Cholesterol Efflux	The investigators will measure circulating metabolite (glucose) and identify the most relevant to the high/low cholesterol efflux phenotype, offering the potential to focus future studies targeting metabolic regulators of efflux.	Baseline
Circulating Metabolite (Creatinine) Linked to Variation Cholesterol Efflux	The investigators will measure circulating metabolite (creatinine) and identify the most relevant to the high/low cholesterol efflux phenotype, offering the potential to focus future studies targeting metabolic regulators of efflux.	Baseline
Circulating Proteins Linked to Variation Cholesterol Efflux	The investigators will measure circulating proteins (apolipoprotein A-I, Albumin, Hemoglobin) and identify the most relevant to the high/low cholesterol efflux phenotype, offering the potential to focus future studies targeting metabolic regulators of efflux.	Baseline

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI)
• Investigators: Principal Investigator: Anand Rohatgi, MD, UT Southwetsern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2017
• Primary Completion (Actual): December 1, 2023
• Study Completion (Actual): May 31, 2025

Study Registration Dates

• First Submitted: July 26, 2019
• First Submitted That Met QC Criteria: August 14, 2019
• First Posted (Actual): August 19, 2019

Study Record Updates

• Last Update Posted (Actual): March 20, 2026
• Last Update Submitted That Met QC Criteria: February 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: HDL; Cholesterol efflux; Atherosclerotic Cardiovascular Disease
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Metabolic Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Nutritional and Metabolic Diseases; Atherosclerosis; Lipid Metabolism Disorders
• Other Study ID Numbers: STU 042016-020; 1R01HL136724-01A1 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No