Dietary Lipid Induced Insulin Resistance

Insulin Resistance Clinical Trial

Official title: Mechanisms of Dietary Lipid Induced Insulin Resistance

Status Active, not recruiting

Clinical Trial Summary

The overall goal of the proposal is to use a saturated fatty acid (SFA)- enriched, high fat diet to rapidly induce insulin resistance (IR) to provide insight into underlying proximal mechanisms of reduced insulin signaling. Specifically, investigators will identify the initial changes in metabolite concentrations/or pathway signaling ("pathways" will be used to broadly refer to these mechanism specific measures) and therefore the mechanisms most likely responsible for the development of IR during this high fat nutritional challenge. Investigators have assembled a multidisciplinary team that is versed with dietary studies, fatty acid metabolism, measurement of IR and potential mechanisms and mediators of IR, and has experience working with monocytes and the two tissues, muscle and adipose tissue, that are particularly relevant for understanding the effects of high fat diets on IR.

Clinical Trial Description

In the first aim, investigators will test whether a short-term high SFA-diet induces and increases insulin resistance in participants with normal and abnormal glucose tolerance, respectively, and determine the associated changes in muscle, adipose tissue and inflammatory cell composition, pathway activation and insulin signaling. Investigators will identify changes in specific signal pathways within these tissues and cells that are hypothesized to mediate or modulate insulin action. Primary mechanisms and pathways examined will include local tissue and systemic inflammation, formation of bioactive lipid intermediates, generation of endoplasmic reticulum (ER) stress, and mitochondrial dysfunction/reactive oxygen formation. By performing studies in participants with normal glucose tolerance and in those with abnormal glucose tolerance investigators will also determine whether the extent and mechanisms of insulin resistance vary with initial degrees of glucose intolerance.

In the second aim, to determine if the extent and mechanisms of insulin resistance vary with dietary composition, investigators will determine whether diets of similar caloric content as the SFA-diet, but enriched in monounsaturated fatty acids or carbohydrates, also induce insulin resistance and whether similar or different mechanistic pathways are responsible. Identifying similarities and differences between diets in inflammatory cell and tissue changes and comparing their relationships with peripheral and tissue insulin action will further clarify which cell and tissue events are most closely linked to development of insulin resistance.

In the final aim, to identify the temporal sequence of mechanistic pathways for insulin resistance and the role of cell and tissue cross-talk in these events, investigators will evaluate inflammatory cell, skeletal muscle and adipose tissue composition and pathway changes after acute, subacute, and more chronic dietary challenges in the same individuals. This will also permit assessment of whether repeated dietary challenges create changes in tissues that resemble those found in more chronic and advanced states of insulin resistance. ;

Related Conditions & MeSH terms

• Insulin Resistance

• NCT number: NCT02757560
• Study type: Interventional
• Source: Phoenix VA Health Care System
• Status: Active, not recruiting
• Phase: N/A
• Start date: February 2012
• Completion date: December 2020