Study of Dietary N-3 Fatty Acids in Patients With Retinitis Pigmentosa and Usher Syndrome

Terminated

• Conditions: Usher Syndrome; Retinitis Pigmentosa

• Registration Number: NCT00004345
• Lead Sponsor: National Center for Research Resources (NCRR)

Brief Summary

OBJECTIVES: I. Examine the concentration of docosahexanoic acid (DHA) and other n-3 fatty acids in plasma, erythrocyte, and adipose tissue in patients with various forms of retinitis pigmentosa and Usher syndrome.

II. Determine the synthesis and catabolism of DHA from linolenic acid in these patients.

III. Determine the synthesis, absorption, and catabolism of DHA under different dietary conditions in these patients.

Detailed Description

PROTOCOL OUTLINE: Patients may participate in one or more of the arms of this study.

Arm I (adipose tissue study): Adipose tissue is collected from the buttocks of patients with Usher II retinitis pigmentosa (RP), patients with non-Usher RP, and control subjects. Dietary histories are obtained from all patients and subjects.

Arm II (isotope study): Patients meeting the same criteria as in arm I receive oral D5-labeled linolenic acid and oral D4-labeled linolenic acid that is dissolved in oil and incorporated into foods. Subjects must avoid eating fish and shellfish during the 35 days of the isotope study. Blood samples are collected at 0, 8, 24, and 48 hours, daily on days 3-7, and then on days 10, 18, and 35.

Arm III (flaxseed oil feeding): Patients with all types of RP and control subjects receive flaxseed oil, a form of linolenic acid, for 12 weeks. Subjects may also receive high oleic safflower oil or olive oil as a control fat for 12 weeks. Subjects complete a diet history at the end of each fatty acid supplementation period. All subjects must follow a diet free of seafood and fish oil supplements.

Study Timeline

• Study Start: 1999-10
• Study First Submitted: 1999-10-18
• Study First Submitted QC: 1999-10-18
• Study First Posted: 1999-10-19
• Status Verified: 2002-07
• Last Update Submitted: 2005-06-23
• Last Update Posted: 2005-06-24

Recruitment & Eligibility

• Status: TERMINATED
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Trial Locations

Locations (1)

Oregon Health Sciences University; 🇺🇸 Portland, Oregon, United States