Organophosphate poisoning and coenzyme Q10: an overview

Abstract

Organophosphate (OP) poisoning can occur in acute and chronic forms. In developing countries, both forms are common, and represent a major cause of morbidity and mortality. In the UK, organophosphate poisoning is most likely to be encountered in chronic form, with sheep farmers the section of the population at greatest risk. The problem of poisoning in sheep farmers caused by exposure to organophosphate-based sheep dips has become increasingly apparent. Symptoms include fatigue, muscle pain and neurological problems. There is no specific treatment for this condition. OP toxicity is classically associated with inhibition of acetylcholinesterase enzymes involved in the process of neurotransmission. However, there is evidence that OP poisoning can also cause mitochondrial dysfunction, compromised cellular energy supply, oxidative stress and inflammation. Symptoms of sheep dip poisoning correspond with those known to result from depletion of coenzyme Q10 (CoQ10), a vitamin-like substance with a key role in cellular energy generation within mitochondria, as well as antioxidant and anti-inflammatory action. The authors have therefore reviewed evidence that oral supplementation with CoQ10 may provide effective symptomatic relief for farmers suffering from OP sheep dip poisoning. Evidence in support of the above is presented for: (a) OP-induced mitochondrial dysfunction; (b) beneficial effects of CoQ10 administration following OP exposure in relevant animal models; and (c) evidence from clinical studies in human subjects. The dosage of CoQ10 proposed (100 mg three times daily) is based on that required to raise blood levels to at least 3 μg/mL, which has been shown to be a requirement to effectively counter CoQ10 depletion in other disorders, particularly heart disease. It is important to note that a CoQ10 supplement with appropriate documented bioavailability should be used, since poor bioavailability may have been responsible for the failure of some previous studies. The safety of CoQ10 supplementation has been confirmed in more than 200 randomised controlled clinical trial studies on a wide range of disorders. In addition to the above, because of the increased risk of the use of OP compounds in terrorist-type poisoning incidents in the UK, a brief discussion on the management of acute OP poisoning is included.