|LE Magazine October 2001|
Page 2 of 4
Mitochondrial encephalomyopathy with coenzyme Q10 deficiency.
Coenzyme Q10 (CoQ10) transfers electrons from complexes I and II of the mitochondrial respiratory chain to complex III. There is one published report of human CoQ10 deficiency describing two sisters with encephalopathy, proximal weakness, myoglobinuria and lactic acidosis. We report a patient who had delayed motor milestones, proximal weakness, premature exertional fatigue and episodes of exercise-induced pigmenturia. She also developed partial-complex seizures. Serum creatine kinase was approximately four times the upper limit of normal and venous lactate was mildly elevated. Skeletal muscle biopsy revealed many ragged-red fibers, cytochrome c oxidase-deficient fibers and excess lipid. In isolated muscle mitochondria, impaired oxygen consumption was corrected by the addition of decylubiquinone. During standardized exercise, ventilatory and circulatory responses were compatible with a defect of oxidation-phosphorylation, which was confirmed by near-infrared spectroscopy analysis. Biochemical analysis of muscle extracts revealed decreased activities of complexes I+II and I+III, while CoQ10 concentration was less than 25% of normal. With a brief course of CoQ10 (150 mg daily), the patient reported subjective improvement. The triad of CNS involvement, recurrent myoglobinuria, and ragged-red fibers should alert clinicians to the possibility of CoQ10 deficiency.
Neurology 1997 May;48(5):1238-43
Control of arterial tone after long-term coenzyme Q10 supplementation in senescent rats.
1. Age-associated deterioration of arterial function may result from long-lasting oxidative stress. Since coenzyme Q (Q10) has been suggested to protect the vascular endothelium from free radical-induced damage, we investigated the effects of long-term dietary Q10 supplementation on arterial function in senescent Wistar rats. 2. At 16 months of age, 18 rats were divided into two groups. The control group was kept on a standard diet while the other group was supplemented with Q10 (10 mg kg(-1) day(-1)). In addition, nine rats (age 2 months) also ingesting a standard diet were used as the young control group. After 8 study weeks the responses of the mesenteric arterial rings in vitro were examined. 3. Endothelium-independent arterial relaxations to isoprenaline and nitroprusside (SNP) were attenuated in aged rats. Increased dietary Q10 clearly enhanced the relaxation to isoprenaline, but did not affect the response to SNP. In addition, vasodilation of noradrenaline-precontracted rings to acetylcholine (ACh), which was also impaired in aged vessels, was improved after Q10 supplementation. Cyclooxygenase inhibition with diclofenac enhanced the relaxation to ACh only in young rats, while it abolished the difference between the old controls and Q10 supplemented rats, suggesting that the improved endothelium-dependent vasodilation observed in Q10 supplemented rats was largely mediated by prostacyclin (PGI2). 4. In conclusion, long-term Q10 supplementation improved endothelium-dependent vasodilation and enhanced beta-adrenoceptor-mediated arterial relaxation in senescent Wistar rats. The mechanisms underlying the improvement of endothelial function may have included augmented endothelial production of PGI2, increased sensitivity of smooth muscle to PGI2 or both.
Br J Pharmacol 1998 Aug;124(7):1500-6
Oral coenzyme Q10 administration prevents the development of ischemic brain lesions in a rabbit model of symptomatic vasospasm.
Treatment with oral coenzyme Q10 (CoQ10, 10 mg/kg per day for 6 days) was compared with no treatment in a previously described rabbit model of symptomatic cerebral vasospasm [Endo et al. (1988) Stroke 19: 1420-1425]. The treatment was initiated within 1-2 h after injection of autologous blood into the subarachnoid space. In CoQ10-untreated rabbits, moderate to severe neurological deficits developed, and multiple focal ischemic lesions were found in the brain regions with compromised blood supply, i.e., in the regions normally supplied by common carotid arteries which are subject to ligation in this model. CoQ10 treatment prevented the development of both the neurological deficits and histologically detectable brain tissue damage. In both CoQ10-treated and -untreated rabbits, infiltration of mononuclear cells was evident in the brain stem, although this region did not show signs of ischemic damage. The findings indicate that the histological and neurological correlates of brain tissue damage in this rabbit model of symptomatic cerebral vasospasm develop via mechanism(s) involving free radical-mediated oxidation of plasma lipoproteins. Similar mechanisms may play a role in the development of brain damage attributed to cerebral atherosclerosis.
Acta Neuropathol (Berl) 1997 Oct;94(4):363-8
Ubiquinone (coenzyme q10) and mitochondria in oxidative stress of Parkinson’s disease.
Parkinson’s disease is the second most common neurodegenerative disorder after Alzheimer’s disease affecting approximately1% of the population older than 50 years. There is a worldwide increase in disease prevalence due to the increasing age of human populations. A definitive neuropathological diagnosis of Parkinson’s disease requires loss of dopaminergic neurons in the substantia nigra and related brain stem nuclei, and the presence of Lewy bodies in remaining nerve cells. The contribution of genetic factors to the pathogenesis of Parkinson’s disease is increasingly being recognized. A point mutation which is sufficient to cause a rare autosomal dominant form of the disorder has been recently identified in the alpha-synuclein gene on chromosome 4 in the much more common sporadic, or ‘idiopathic’ form of Parkinson’s disease, and a defect of complex I of the mitochondrial respiratory chain was confirmed at the biochemical level. Disease specificity of this defect has been demonstrated for the parkinsonian substantia nigra. These findings and the observation that the neurotoxin 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP), which causes a Parkinson-like syndrome in humans, acts via inhibition of complex I have triggered research interest in the mitochondrial genetics of Parkinson’s disease. Oxidative phosphorylation consists of five protein-lipid enzyme complexes located in the mitochondrial inner membrane that contain flavins (FMN, FAD), quinoid compounds (coenzyme Q10, CoQ10) and transition metal compounds (iron-sulfur clusters, hemes, protein-bound copper). These enzymes are designated complex I (NADH:ubiquinone oxidoreductase, EC 1.6. 5.3), complex II (succinate:ubiquinone oxidoreductase, EC 188.8.131.52), complex III (ubiquinol:ferrocytochrome c oxidoreductase, EC 184.108.40.206), complex IV (ferrocytochrome c:oxygen oxidoreductase or cytochrome c oxidase, EC 220.127.116.11), and complex V (ATP synthase, EC 18.104.22.168). A defect in mitochondrial oxidative phosphorylation, in terms of a reduction in the activity of NADH CoQ reductase (complex I) has been reported in the striatum of patients with Parkinson’s disease. The reduction in the activity of complex I is found in the substantia nigra, but not in other areas of the brain, such as globus pallidus or cerebral cortex. Therefore, the specificity of mitochondrial impairment may play a role in the degeneration of nigrostriatal dopaminergic neurons. This view is supported by the fact that MPTP generating 1-methyl-4-phenylpyridine (MPP(+)) destroys dopaminergic neurons in the substantia nigra. Although the serum levels of CoQ10 is normal in patients with Parkinson’s disease, CoQ10 is able to attenuate the MPTP-induced loss of striatal dopaminergic neurons.
Biol Signals Recept 2001 May-Aug;10(3-4):224-53
Two successful double-blind trials with coenzyme Q10 (vitamin Q10) on muscular dystrophies and neurogenic atrophies.
Coenzyme Q10 (vitamin Q10) is biosynthesized in the human body and is functional in bioenergetics, anti-oxidation reactions, and in growth control, etc. It is indispensable to health and survival. The first double-blind trial was with twelve patients, ranging from 7 to 69 years of age, having diseases including the Duchenne, Becker, and the limb-girdle dystrophies, myotonic dystrophy. Charcot-Marie-Tooth disease, and the Welander disease. The control coenzyme Q10 (CoQ10) blood level was low and ranged from 0.5 to 0.84 microgram/ml. They were treated for three months with 100 mg daily of CoQ10 and a matching placebo. The second double-blind trial was similar with fifteen patients having the same categories of disease. Since cardiac disease is established to be associated with these muscle diseases, cardiac function was blindly monitored, and not one mistake was made in assigning CoQ10 and placebo to the patients in both trials. Definitely improved physical performance was recorded. In retrospect, a dosage of 100 mg was too low although effective and safe. Patients suffering from these muscle dystrophies and the like, should be treated with vitamin Q10 indefinitely.
Biochim Biophys Acta 1995 May 24;1271(1):281-6
Coenzyme Q10 and nicotinamide block striatal lesions produced by the mitochondrial toxin malonate.
A potential mechanism of neuronal injury in neurodegenerative diseases is a defect in energy metabolism that may lead to slow excitotoxic neuronal death. Consistent with this possibility, we showed that specific inhibitors of the electron transport chain produce excitotoxic lesions in vivo. In the present study we examined whether agents that improve energy metabolism can block lesions produced by the mitochondrial toxin malonate. Striatal lesions produced by the complex II inhibitor malonate were blocked in a dose-dependent manner by oral pretreatment with coenzyme Q10. Administration of nicotinamide by Alzet pump for 1 week attenuated malonate-induced lesions, but riboflavin had no effect. Administration of nicotinamide intraperitoneally just prior to and following induction of the lesions produced dose-dependent neuroprotection. A combination of coenzyme Q10 with nicotinamide was more effective than either compound alone, as shown by both lesion size and magnetic resonance imaging in vivo. Both coenzyme Q10 and nicotinamide blocked adenosine triphosphate depletions and lactate increases. These results confirm that mitochondrial toxins produce striatal excitotoxic lesions by a mechanism involving energy depletion in vivo. Furthermore, they suggest novel neuroprotective strategies that may be useful in the treatment of both mitochondrial encephalopathies and neurodegenerative diseases.
Ann Neurol 1994 Dec;36(6):882-8
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