Protocol Number: 03-EI-0255

Title:

Pilot Study on the Effect of Vitamin A Supplementation on Cone Function in Retinitis Pigmentosa

Number:

03-EI-0255

Summary:

Vitamin A is an essential nutrient that cannot be made in the body, and it is difficult to get significant amounts of vitamin A from food sources.

The purpose of this study is to determine whether taking an oral vitamin A supplement will improve the retinal function of patients with retinitis pigmentosa (RP). Patients with RP progressively lose the ability to read fine print and perceive color.

Fifteen participants age 18 and older who have various types of RP will participate in this study. They will take vitamin A capsules (doses of 15,000 IU to 50,000 UI) daily for 4 weeks; then they will switch to a lower dose for an additional 2 weeks. At an initial visit to the Clinical Center, participants will undergo a medical history, physical exam, blood work, and an eye exam that includes an electroretinogram. During each of five follow-up visits, doctors will measure the amount of vitamin A in participants' blood to see if it increases over time. The follow-up visits will take place approximately every 2 weeks for approximately 2.5 months.

Sponsoring Institute:

National Eye Institute (NEI)

Recruitment Detail

Type: Active Accrual Of New Subjects

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): Children

Eligibility Criteria:

INCLUSION CRITERIA:

All participants must meet the following criteria to participate in the study.

1. Men and women age 18 years of age and older.

2. Diagnoses of typical RP of all genetic subtypes (simplex, autosomal dominant, autosomal recessive, and X-linked), as determined primarily by abnormally reduced ERG rod response amplitudes that are relatively more affected than cone ERG amplitudes.

3. Participants in whom flicker ERG can be measured reliably (standard flicker ERG amplitude greater than 2 mV).

4. Willingness to use contraception for the duration of the study.

5. Understood and signed consent.

EXCLUSION CRITERIA:

Participants with the following conditions will be excluded from study.

1. Participants with syndromic RP (i.e., Ushers syndrome).

2. Have abnormal liver function (greater ULN ALT, AST, Alkaline Phosphate, or Total Bilirubin).

3. Hematocrit greater than 1.5 x ULN

4. Have abnormal kidney function (greater than1.5 mg/dl serum creatinine).

5. Currently or has taken vitamin A supplementation within 6 months of the first screening visit.

6. Is pregnant or lactating (due to evidence that sugests excessive intake of vitamin A could be tertogenic in humans and affect the content of breast milk).

7. Currently or has taken greater than 400 IU/day of vitamin E supplementation within 6 months of enrollment.

8. Vitamin A serum level exceeding 150 mg/dL.

Special Instructions: Currently Not Provided

Keywords:

Retinitis Pigmentosa

Vitamin A

ERG

Recruitment Keywords:

Retinitis Pigmentosa

RP

Vitamin A

Conditions:

Retinitis Pigmentosa

Investigational Drug(s):

Vitamin A

Investigational Device(s):

None

Contacts:

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793

Electronic Mail:prpl@mail.cc.nih.gov

Citations:

Phelan JK, Bok D. A brief review of retinitis pigmentosa and the identified retinitis pigmentosa genes. Mol Vis. 2000 Jul 8;6:116-24. Review. PMID: 10889272

Milam AH, Li ZY, Fariss RN. Histopathology of the human retina in retinitis pigmentosa. Prog Retin Eye Res. 1998 Apr;17(2):175-205. Review. PMID: 9695792

Huang PC, Gaitan AE, Hao Y, Petters RM, Wong F. Cellular interactions implicated in the mechanism of photoreceptor degeneration in transgenic mice expressing a mutant rhodopsin gene. Proc Natl Acad Sci U S A. 1993 Sep 15;90(18):8484-8. PMID: 8378322

• Questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.
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