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

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

TERMINATED

Total Enrollment

100 participants

Study Classification

OBSERVATIONAL

Study Start Date

1999-10-31

Brief Summary

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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

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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.

Conditions

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Usher Syndrome Retinitis Pigmentosa

Eligibility Criteria

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Inclusion Criteria

PROTOCOL ENTRY CRITERIA:

* Retinitis pigmentosa, including: Usher syndrome (types I and II) Simplex
* The following inheritance patterns eligible: X-linked recessive; Autosomal dominant; Autosomal recessive

Minimum Eligible Age

0 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Principal Investigators

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William Connor

Role: STUDY_CHAIR

Oregon Health and Science University

Locations

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Oregon Health Sciences University

Portland, Oregon, United States

Site Status

Countries

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United States

References

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Schwartz SG, Wang X, Chavis P, Kuriyan AE, Abariga SA. Vitamin A and fish oils for preventing the progression of retinitis pigmentosa. Cochrane Database Syst Rev. 2020 Jun 18;6(6):CD008428. doi: 10.1002/14651858.CD008428.pub3.

Reference Type DERIVED

PMID: 32573764 (View on PubMed)

Other Identifiers

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OHSU-2650

Identifier Type: -

Identifier Source: secondary_id

199/11904