An observational study in Obesity, Cardiovascular Risk Factor and Hyperlipidemia, sponsored by Susan Smyth. Terminated at 1 site in United States. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-07-21.
Sponsored by Susan Smyth · Observational
This study aims to test the hypothesis that dietary intake of phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) acutely alters plasma lysophosphatidic acid (LPA) levels and autotaxin activity in normal weight and obese subjects.
Lysophosphatidic acid (LPA) is a simple glycerophospholipid that is found at biologically-relevant levels in plasma and has important effects on isolated or cultured blood, vascular and fat cells. The main enzyme responsible for generation of plasma LPA is the secreted lysophospholipase D, autotaxin (ATX). Adipocytes contribute substantially to plasma ATX levels. The investigators have demonstrated rapid production and metabolism of plasma LPA in animals. More recently, the investigators have observed that plasma LPA levels increase in mice fed a high fat ("Western") diet in comparison to levels found in mice fed normal chow. The investigators have also found that diet-induced obesity increased circulating ATX levels in mice. The investigators hypothesize that diet, and in particular dietary phosphatidylcholine (PC), may regulate the autotaxin substrate lysophosphatidylcholine (LPC), from which LPA is derived. Obesity may amplify the response by increasing plasma ATX levels and/or activity. The current study will test whether dietary PC in normal weight and obese subjects acutely alters LPA levels and autotaxin activity.
821 studies on the registry are indexed under Hyperlipidemias; 105 are open to participants now.
This study's enrollment of 44 is below the median of 302 across 101 observational studies indexed under Hyperlipidemias.
Browse Hyperlipidemias studies →Susan Smyth is the lead sponsor of 4 studies on the registry; none are open to participants now.
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Subjects 18 years of age or older with no major health issues
Exclusion Criteria:
BMI is between 20 and 25
BMI is between 25 and 30
BMI is between 30 and 40
Plasma Autotaxin-dependent formation of Lysophosphatidic acid, and Levels of Phosphatidylcholine and its metabolites - Lysophosphatidylcholine, Lysophosphatidic acid, Choline, Trimethylamine and Trimethylamine oxide measured by Tandem Mass Spectrometry
Investigators will use tandem mass spectrometry to measure the most abundant metabolite species. Enzymatic activity of autotaxin involves incubation with the substrate lysophosphatidylcholine and monitoring concentration dependent release of lysophosphatidic acid. Levels of Lysophospholipids Phosphatidylcholine and the products of its metabolism in the blood will be measured. Quantitation will be achieved by stable isotope dilution and by reference to offline calibration curves. By using mass spectrometry and metabolic tracers, studies using a common protocol are effectively multiplexed so data on both endogenous and mass labeled lipids can be obtained from a single individual. Given the sensitivity of these analytical methods (limits of quantitation of approximately 1 fmol), the measurements and the quantities will be reported as concentration in picomoles per liter of plasma volume. A statistical correlation with each group based on BMI will be performed.
Time frame: 8 hours
Plan to share: No — We do not plan to share individual participant data.
No publications or documents are linked to this record.
This study is terminated, as verified in Jul 2021. You cannot join it, but the record below documents what was studied.
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Susan Smyth