In the previous EduFacts (Volume 4, Number 6) we summarized preliminary work by Horrobin and colleagues (1) which indicated that an effective approach to the treatment of dry eye disorders may be to address the biochemical basis of an intact tear film. In this preliminary study the authors had evaluated the use of supplemental intake of the essential fatty acids (EFA); linoleic and gamma linolenic acids; vitamin B6 ; and vitamin C to treat dry eye. These nutrients are necessary components of the pathway for biosynthesis of prostaglandin E1 (PGE1), which is necessary for aqueous tear secretion by the lacrimal glands. The rationale for their study was based on earlier research showing that gamma linolenic acid (GLA), an upstream metabolite of the EFA linoleic acid, was lower among patients with Sjögren's Syndrome. This suggested a breakdown in the biochemical pathway which might be remedied by supplying both GLA, linoleic acid and the vitamin cofactors involved.

Another controlled study of treatment with precursor EFAs was performed by Oxholm and colleagues on patients with primary Sjögren's Syndrome (2).

Methods:

28 patients with primary Sjögren's Syndrome were studied in a "cross-over" clinical study. Each patient received either Efamol (73% cis-linoleic acid, 9% gamma linolenic acid) or placebo for 8 weeks. Dosing was 6 3g capsules daily. Then each patient was "crossed-over" and received the opposite treatment for 8 more weeks. The initial treatment assignment was randomly chosen for each patient and the study was double masked - neither patients nor clinicians knew the treatment given to the patient. Clinical tests for keratoconjunctivitis sicca (KCS) included Schirmer test, tear-break-up-time, and Bijstervald score. These tests were evaluated before and after treatment. A combined ocular score was also computed. In addition the levels of DGLA (a metabolite of linoleic acid produced during biosynthesis of PGE1) were measured in serum and in erythrocytes before and after treatment.

Results:

Statistically significant baseline-to-post-treatment improvement in the overall ocular score was found in the Efamol group (p<0.05). Fewer patients in the control group experienced improvement (baseline-to-post-treatment) in ocular score. Furthermore, levels of the metabolite Di-hommo-gamma linolenic acid (DGLA) were increased significantly in both plasma (25% increase, p<0.001), and erythrocytes (10% increase, p<0.05) during Efamol treatment but not placebo treatment.

References

1. Horrobin DF, Campbell A, McEwen CG: Treatment of the Sicca Syndrome and the Sjögren's Syndrome with E.F.A., Pyroxidine and vitamin C. Prog Lipid Res 8(4): 253-4, 1981.
2. 2. Oxholm P, Manthorpe R, Prause JU, Horrobin D: Patients with Primary Sjögren's Syndrome Treated for 2 Months With Evening Primrose Oil. Scand J Rheumatology 1986; 15:103-108.