Clinical aspects of coenzyme Q10: an update.
The fundamental role of coenzyme Q(10) (CoQ(10)) in mitochondrial bioenergetics and its well-acknowledged antioxidant properties constitute the basis for its clinical applications, although some of its effects may be related to a gene induction mechanism. Cardiovascular disease is still the main field of study and the latest findings confirm a role of CoQ(10) in improving endothelial function. The possible relation between CoQ(10) deficiency and statin side effects is highly debated, particularly the key issue of whether CoQ(10) supplementation counteracts statin myalgias. Furthermore, in cardiac patients, plasma CoQ(10) was found to be an independent predictor of mortality. Studies on CoQ(10) and physical exercise have confirmed its effect in improving subjective fatigue sensation and physical performance and in opposing exercise-related damage. In the field of mitochondrial myopathies, primary CoQ(10) deficiencies have been identified, involving different genes of the CoQ(10) biosynthetic pathway; some of these conditions were found to be highly responsive to CoQ(10) administration. The initial observations of CoQ(10) effects in Parkinson's and Huntington's diseases have been extended to Friedreich's ataxia, where CoQ(10) and other quinones have been tested. CoQ(10) is presently being used in a large phase III trial in Parkinson's disease. CoQ(10) has been found to improve sperm count and motility on asthenozoospermia. Moreover, for the first time CoQ(10) was found to decrease the incidence of preeclampsia in pregnancy. The ability of CoQ(10) to mitigate headache symptoms in adults was also verified in pediatric and adolescent populations.
Nutrition. 2010 Mar;26(3):250-4
The reduced form of coenzyme Q10 improves glycemic control in patients with type II diabetes: An open label pilot study.
Coenzyme Q10 (CoQ10) provides the energy for vital cellular functions and is known to act as an antioxidant. We conducted an open label study to examine the clinical effects of supplementation of the reduced form of CoQ10, ubiquinol, in addition to conventional glucose-lowering agents in patients with type II diabetes. Nine subjects (3 males and 6 females) with type II diabetes and receiving conventional medication were recruited. The subjects were assigned to receive an oral dose of 200 mg ubiquinol daily for 12 weeks. The effect of ubiquinol on blood pressure, lipid profile, glycemic control, oxidative stress, and inflammation were examined before and after ubiquinol supplementation. In addition, five healthy volunteers were also assigned to receive an oral dose of 200 mg ubiquinol daily for 4 weeks to examine the effects of ubiquinol on insulin secretion. In patients with diabetes, there were no differences with respect to blood pressure, lipid profile, oxidative stress marker, and inflammatory markers. However, there were significant improvements in glycosylated hemoglobin (53.0 ± 4.3 to 50.5 ± 3.7 mmol/mol, P = 0.01) (7.1 ± 0.4 to 6.8 ± 0.4%, P = 0.03). In healthy volunteers, the insulinogenic index (0.65 ± 0.29 to 1.23 ± 0.56, P = 0.02) and the ratio of proinsulin to insulin were significantly improved (3.4 ± 1.8 to 2.1 ± 0.6, P = 0.03). The results of our study are consistent with the suggestion that the supplementation of ubiquinol in subjects with type 2 diabetes, in addition to conventional antihyperglycemic medications, improves glycemic control by improving insulin secretion without any adverse effects.
Biofactors. 2012 Aug 8. doi: 10.1002/biof.1038
The reduced form of coenzyme Q10 decreases the expression of lipopolysaccharide-sensitive genes in human THP-1 cells.
Monocytes are key players in inflammatory processes that are triggered by lipopolysaccharide (LPS), the major outer membrane component of Gram-negative bacteria. The present study in human monocytic THP-1 cells was designed in order to identify LPS-inducible genes that are down-regulated by the reduced form of coenzyme Q(10) (ubiquinol, Q(10)H(2)). For this purpose, THP-1 cells were incubated with 10 µM Q(10)H(2) for 24 hours. Subsequently, cells were stimulated for 4 hours with 1 µg/mL LPS, and the resulting gene expression levels were determined using microarrays. Fourteen LPS-inducible genes were identified to be significantly (P ≤ .05) down-regulated by Q(10)H(2) pretreatment between a factor of 1.32 and 1.65. The strongest effect of Q(10)H(2) incubation was found for the nuclear receptor coactivator 2 gene (NCOA2). Gene ontology terms revealed for the Q(10)H(2)-sensitive genes an involvement in, e.g., signal transduction processes (centaurin, delta 1; NCOA2; pleckstrin and Sec7 domain containing 3; protein phosphatase 2, regulatory subunit B [B56], γ isoform), transcriptional regulation (NCOA2; POU domain, class 2, transcription factor 1; ETS variant gene 3), and cell proliferation pathways (hypothetical protein FLJ36090, epidermal growth factor receptor pathway substrate 15). In conclusion, we provide evidence in THP-1 cells that Q(10)H(2) modulates LPS-induced gene expression.
J Med Food. 2011 Apr;14(4):391-7
Coenzyme Q10 protects against amyloid beta-induced neuronal cell death by inhibiting oxidative stress and activating the P13K pathway.
Oxidative stress plays critical roles in the pathogenic mechanisms of several neurodegenerative disorders including Alzheimer's disease (AD), thus much research effort has focused on antioxidants as potential treatment agents for AD. Coenzyme Q10 (CoQ10) is known to have powerful antioxidant effects. We investigated the neuroprotective effects of CoQ10 against Amyloid beta(25-35) (Aβ(25-35))-induced neurotoxicity in rat cortical neurons. To evaluate the neuroprotective effects of CoQ10 on Aβ(25-35)-injured neurons, primary cultured cortical neurons were treated with several concentrations of CoQ10 and/or Aβ(25-35) for 48h. CoQ10 protected neuronal cells against Aβ(25-35)-induced neurotoxicity in a concentration-dependent manner. These neuroprotective effects of CoQ10 were blocked by LY294002 (10µM), a phosphatidylinositol 3-kinase (PI3K) inhibitor. Aβ(25-35) concentration-dependent increased free radical levels in rat cortical neurons, while combined treatment with CoQ10 reduced these free radical levels in a dose-dependent manner. Meanwhile, CoQ10 treatment of Aβ(25-35)-injured primary cultured cortical neurons increased the expression levels of p85aPI3K, phosphorylated Akt, phosphorylated glycogen synthase kinase-3β, and heat shock transcription factor, which are proteins related to neuronal cell survival, and decreased the levels of cytosolic cytochrome c and cleaved caspase-3, which are associated with neuronal cell death. Together, these results suggest that the neuroprotective effects of CoQ10 on Aβ(25-35) neurotoxicity are mediated by inhibition of oxidative stress together with activation of the PI3-K/Akt pathway.
Neurotoxicology. 2012 Jan;33(1):85-90
Parkinson's disease: mitochondrial molecular pathology, inflammation, statins, and therapeutic neuroprotective nutrition.
Pathological hallmarks of Parkinson's disease are destruction of dopaminergic neurons in the basal ganglia, especially the substantia nigra, and the presence of Lewy bodies within nerve cells. Environmental toxins are associated with the disease and, in a minority of cases, genetic factors have been identified. Inflammation-with activation of phagocytic microglia, release of cytokines, invasion by T cells, and complement activation-plays a role in damaging these neurons. Excessive production of reactive oxygen species, mitochondrial dysfunction leading to apoptosis, accumulation and oligomerization of the protein alpha-synuclein, and defective protein disposal by the ubiquitin proteasome system are involved in the complex web of events mediating nigral cell demise. Two agents of current interest, coenzyme Q10 and creatine, may be disease modifying, and large studies are in progress. Related mechanisms of other substances, including omega-3 fatty acids and vitamin D, are included in this review. The association with serum cholesterol levels and the effects of statin drugs are uncertain but important.
Nutr Clin Pract. 2010 Aug;25(4):371-89
Cellular and molecular mechanisms of antioxidants in Parkinson's disease.
Parkinson's disease (PD) is a neurodegenerative movement disorder characterized by the degeneration and progressive loss of dopaminergic neurons in the substantia nigra pars compacta. It has been suggested that oxidative stress plays a role in the etiology and progression of PD. For instance, low levels of endogenous antioxidants, increased reactive species, augmented dopamine oxidation, and high iron levels have been found in brains from PD patients. In vitro and in vivo studies of Parkinson models evaluating natural and endogenous antioxidants such as polyphenols, coenzyme Q10, and vitamins A, C, and E have shown protective effects against oxidative-induced neuronal death. In this paper, we will review the mechanisms by which polyphenols and endogenous antioxidants can produce protection. Some of the mechanisms reviewed include: scavenging nitrogen and oxygen reactive species, regulation of signaling pathways associated with cell survival and inflammation, and inhibition of synphilin-1 and alpha-synuclein aggregation.
Nutr Neurosci. 2012 May;15(3):120-6
Nutraceuticals and their preventive or potential therapeutic value in Parkinson's disease.
Parkinson's disease (PD) is the second most common aging-related disorder in the world, after Alzheimer's disease. It is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta and other parts of the brain, leading to motor impairment, cognitive impairment, and dementia. Current treatment methods, such as L-dopa therapy, are focused only on relieving symptoms and delaying progression of the disease. To date, there is no known cure for PD, making prevention of PD as important as ever. More than a decade of research has revealed a number of major risk factors, including oxidative stress and mitochondrial dysfunction. Moreover, numerous nutraceuticals have been found to target and attenuate these risk factors, thereby preventing or delaying the progression of PD. These nutraceuticals include vitamins C, D, E, coenzyme Q10, creatine, unsaturated fatty acids, sulfur-containing compounds, polyphenols, stilbenes, and phytoestrogens. This review examines the role of nutraceuticals in the prevention or delay of PD as well as the mechanisms of action of nutraceuticals and their potential applications as therapeutic agents, either alone or in combination with current treatment methods.
Nutr Rev. 2012 Jul;70(7):373-86
A review on the oxidative and nitrosative stress (O&NS) pathways in major depression and their possible contribution to the (neuro)degenerative processes in that illness.
This paper reviews the body of evidence that major depression is accompanied by a decreased antioxidant status and by induction of oxidative and nitrosative (IO&NS) pathways. Major depression is characterized by significantly lower plasma concentrations of a number of key antioxidants, such as vitamin E, zinc and coenzyme Q10, and a lowered total antioxidant status. Lowered antioxidant enzyme activity, e.g. glutathione peroxidase (GPX), is another hallmark of depression. The abovementioned lowered antioxidant capacity may impair protection against reactive oxygen species (ROS), causing damage to fatty acids, proteins and DNA by oxidative and nitrosative stress (O&NS). Increased ROS in depression is demonstrated by increased levels of plasma peroxides and xanthine oxidase. Damage caused by O&NS is shown by increased levels of malondialdehyde (MDA), a by-product of polyunsaturated fatty acid peroxidation and arachidonic acid; and increased 8-hydroxy-2-deoxyguanosine, indicating oxidative DNA damage. There is also evidence in major depression, that O&NS may have changed inactive autoepitopes to neoantigens, which have acquired immunogenicity and serve as triggers to bypass immunological tolerance, causing (auto)immune responses. Thus, depression is accompanied by increased levels of plasma IgG antibodies against oxidized LDL; and increased IgM-mediated immune responses against membrane fatty acids, like phosphatidyl inositol (Pi); oleic, palmitic, and myristic acid; and NO modified amino-acids, e.g. NO-tyrosine, NO-tryptophan and NO-arginine; and NO-albumin. There is a significant association between depression and polymorphisms in O&NS genes, like manganese superoxide dismutase, catalase, and myeloperoxidase. Animal models of depression very consistently show lowered antioxidant defences and activated O&NS pathways in the peripheral blood and the brain. In animal models of depression, antidepressants consistently increase lowered antioxidant levels and normalize the damage caused by O&NS processes. Antioxidants, such as N-acetyl-cysteine, compounds that mimic GPX activity, and zinc exhibit antidepressive effects. This paper reviews the pathways by which lowered antioxidants and O&NS may contribute to depression, and the (neuro)degenerative processes that accompany that illness. It is concluded that aberrations in O&NS pathways are—together with the inflammatory processes—key components of depression. All in all, the results suggest that depression belongs to the spectrum of (neuro)degenerative disorders.
Prog Neuropsychopharmacol Biol Psychiatry. 2011 Apr 29;35(3):676-92
Mitochondrial modulators for bipolar disorder: A pathophysiologically informed paradigm for new drug development.
Objectives: Bipolar patients frequently relapse within 12 months of their previous mood episode, even in the context of adequate treatment, suggesting that better continuation and maintenance treatments are needed. Based on recent research of the pathophysiology of bipolar disorder, we review the evidence for mitochondrial dysregulation and selected mitochondrial modulators (MM) as potential treatments.Methods: We reviewed the literature about mitochondrial dysfunction and potential MMs worthy of study that could improve the course of bipolar disorder, reduce subsyndromal symptoms, and prevent subsequent mood episodes.Results: MM treatment targets mitochondrial dysfunction, oxidative stress, altered brain energy metabolism and the dysregulation of multiple mitochondrial genes in patients with bipolar disorder. Several tolerable and readily available candidates include N-acetyl-cysteine (NAC), acetyl-L-carnitine (ALCAR), S-adenosylmethionine (SAMe), coenzyme Q(10) (CoQ10), alpha-lipoic acid (ALA), creatine monohydrate (CM), and melatonin. The specific metabolic pathways by which these MMs may improve the symptoms of bipolar disorder are discussed and combinations of selected MMs could be of interest as well.Conclusions: Convergent data implicate mitochondrial dysfunction as an important component of the pathophysiology of bipolar disorder. Clinical trials of individual MMs as well as combinations are warranted
Aust N Z J Psychiatry. 2012 Jun 18
Coenzyme Q10, copper, zinc, and lipid peroxidation levels in serum of patients with chronic obstructive pulmonary disease.
Severity of chronic obstructive pulmonary disease (COPD) exacerbation is associated with increased level of copper (Cu), zinc (Zn), and lipid peroxidation (malodialdehyde, MDA). The aim of this study was to investigate the levels of lipid peroxidation, Coenzyme Q10 (CoQ10), Zn, and Cu in the COPD exacerbations. Forty-five patients with COPD acute exacerbation and 45 healthy smokers as control group were used in the study. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were lower in exacerbation group than in control. C- reactive protein levels, white blood cell count, and sedimentation rate were significantly (p<0.001) higher in patients than in control. CoQ10 level and Cu/Zn ratio was significantly (p<0.05) lower in patients than in control, although MDA, Cu, and Zn levels were significantly (p<0.05) higher in patients than in control. Negative correlations were found among MDA, Cu, Zn, FEV1, and FVC values in exacerbation and control subjects (p<0.05). In conclusion, we observed that oxidative stress in the exacerbation period of COPD patients was increased. The decrease in CoQ10 level and Cu/Zn ratio and elevation in Cu and Zn levels observed in the patients probably result from the defense response of organism and are mediated by inflammatory-like substances.
Biol Trace Elem Res. 2011 Nov;143(2):659-67