A Randomized, Double-blind, Placebo-controlled Trial of Curcumin in Leber's Hereditary Optic Neuropathy (LHON)

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disease that is characterized by a simultaneous or more common sequential bilateral loss of central vision, which typically occurs during the teenager years or early adulthood. The disease may be progressive and the patients eventually become blind. In contrast to blindness in patients caused by congenital diseases, the patients who develop blindness caused by LHON will have more trouble in their life because they previously had better vision. Although LHON is associated with mitochondrial DNA mutation at a variable nucleotide position but no certain mechanism of optic nerve injury has been found. It has been postulated that a defect in a complex of respiratory chain enzyme which is caused by mitochondrial DNA dysfunction, results in an increase of free radical substances that interfere with optic nerve function in LHON. Some antioxidant substances have been used to decrease the progression of visual impairment. However, there have been few therapeutic trials for LHON.

Curcumin, a component of tumeric, which comes from the root Curcumin longa has antioxidant, anti-inflammatory and anti-carcinogenic activities. There is some evidence which suggests that curcumin contributes to the in vitro removal of free radical gradients in thalassemic serum and to a clinical improvement of thalassemic patients. We propose a randomized controlled trial study of curcumin, which is an antioxidant substance, for LHON. This study will provide not only an insight into the therapeutic efficacy of curcumin, a kind of Thai herb, for LHON but also the development of future therapeutic strategies to prevent blindness.