the effect of oral administration of 9-cis rich powder of the alga dunaliella bardawil on visual functions in adolescent patients with retinitis pigmentosa

Conditions: Retinitis Pigmentosa

Summary: the aim of this study is to determine whether 9-cis-beta caroten rich d. brdawiil extract is effective in the treatment of retinitis pigmentosa in adolescent patients.

retinitis pigmentosa is a genetically disease consisting of progressive retinal degeneration starting in the rods. its prevalence is 1:4000 people and is the fourth most common blinding disease in israel in 2004 \[7% of all blindness\]. the investigators treated a non-progressive form of the disease \[fundus albipunctatus\] by oral therapy of the food supplement made from alga dunaliella bardawil composed of approximately 50% 9-cis β-carotene. the 9-cis β -carotene has been shown to be a precursor of 9-cis retinoic acid both in-vitro in human intestinal mucosa and in-vivo in a ferret, perfused with 9-cis b-carotene. the night vision, as measured objectively by electroretinography (erg) more than doubled in six patients tested following treatment. the visual field was also improved significantly. in a more recent study the investigators treated 29 retinitis pigmentosa patients with the 9-cis b carotene algae dunaliella bardawil in a double masked placebo control cross over trial. significant improvement in retinal function was recorded in 34% of the patients. as a natural extension of this study we will perform a double-masked, randomized, crossover, placebo-controlled study for adolescent patients. longer treatment duration will be tested: a 24 week treatment with either the 9-cis β-carotene-rich capsules or placebo followed by an additional a 24 week treatment with the other capsules and a wash-out period of 24 weeks between this two type of treatments. we predict that with this study design a maximal/increased therapeutic effect as well as efficient washout will be achieved.

Eligibility criteria:
inclusion criteria: * written informed consent to participate in the study. * adolescent 12-18 years old. * electroretinogram (erg) responses compatible with the diagnosis of retinitis pigmentosa exclusion criteria: * currently a smoker * current use of vitamin a/ β-carotene supplements * active arterial disease within 3 months prior to enrolment in the study, e.g. unstable angina, myocardial infarction, transient ischemic attack, stroke, coronary artery bypass graft surgery * history of malignancy, excepting basal or squamous cell skin carcinoma * females who are pregnant, or breast feeding, or are premenopausal but not using chemical or mechanical contraception * uncontrolled hypertension, defined either as resting diastolic blood pressure \>95 mmhg (taken from the mean of 3 readings) or as resting systolic blood pressure \>180 mmhg * history of alcohol abuse or drug abuse or both * intention to engage in vigorous exercise or an aggressive diet regimen * uncontrolled endocrine or metabolic disease * participation in another investigational drug study within 4 weeks prior to enrolment * serious or unstable medical or psychological condition which, in the opinion of the pi, would compromise the subject's safety or successful participation in the study * initiation of hormone replacement therapy or oral contraceptive therapy within 3 months prior to enrolment