Zinc and Diabetes in Patients With Thalassemia: a Pilot Study
|Study Design:||Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
|Official Title:||Zinc and Diabetes in Patients With Thalassemia: a Pilot Study|
- Oral glucose Tolerance Test [ Time Frame: 3 months ] [ Designated as safety issue: No ]Effect of 3 months of zinc supplementation on oral glucose tolerance test results
- Fructosamine [ Time Frame: 3 months ] [ Designated as safety issue: No ]Determine the effect of 3 months of zinc supplementation on fructosamine levels
|Study Start Date:||November 2012|
|Study Completion Date:||May 2015|
|Primary Completion Date:||January 2015 (Final data collection date for primary outcome measure)|
Experimental: Zinc Supplementation
25 mg elemental Zinc as Zn sulfate in capsule form taken daily for 3 months
Dietary Supplement: Zinc Supplementation
25 mg elemental zinc taken as zinc sulfate in capsule form taken daily for 3 months
Patients with Thalassemia major (Thal) require frequent blood transfusions and are at risk for iron overload. High tissue iron increases the risk of various endocrinopathies, including diabetes, as well as cardiovascular disease, and infections due to the formation of free radicals. This systemic condition of oxidative stress elicits an antioxidant response to reduce tissue damage. Zinc is an important component of that response because it can compete with iron for multiple cellular binding sites and, therefore, reduce the redox-cycling of iron and minimize iron-mediated oxidation of lipids, proteins, and DNA.
In Thal patients with chronic hepatic iron overload, tissue zinc redistribution is likely to be persistent. This could create an unbalanced tissue zinc distribution with excessive amounts in the liver and deficient levels in other tissues altering zinc-dependent functions, such as growth, skeletal development, immunity, and glucose regulation. There is a rich body of literature focused on the 'diabetogenic effects' of altered zinc status which will be reviewed herein. Our group has recently shown that supplementation with 25 mg/d of zinc can improve bone density in patients with Thal. This provides evidence for a functional zinc deficiency, which may also affect other whole body zinc functions, such as insulin secretion and glucose homeostasis.
Our hypothesis is that hepatic iron overload induces a sub-clinical inflammatory response that alters the expression of MT and zinc-transport proteins leading to hepatic zinc sequestration, and an associated zinc-depletion in other tissues. Marginal zinc depletion in turn leads to increased oxidative stress, cellular apoptosis and altered glucose homeostasis and insulin secretion. This proposal will focus on cross-sectional differences in markers of glucose homeostasis and zinc status in diabetic and non-diabetic Thal patients, combined with a short- term zinc supplementation to explore the effect on glucose and insulin homeostasis.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01772680
|United States, California|
|Children's Hospital & Research Center Oakland|
|Oakland, California, United States, 94609|
|Principal Investigator:||Ellen B Fung, PhD RD||Children's Hospital & Research Center Oakland|