Cardiovascular diseases, oxidative stress and antioxidants: the decisive role of coenzyme Q10.

In his timely article [1], Dr. P.K. Singal reviews the More recently, the results of 34 controlled clinical trials relationship between oxidative stress, antioxidants and and many open-label and long-term studies were reviewed cardiac diseases. This field is the most extensively investi[2]. The largest study to date involves 2359 patients and gated area of cardiovascular research with consequential the participation of cardiologists in 173 Italian hospital practical therapeutic ramifications. Unfortunately, the aucenters. A table summarizing the current indications for thor’s presentation of the clinical effectiveness of various clinical use of CoQ in various forms of cardiovascular 10 antioxidants in the prevention or restriction of the molecudiseases is presented in Ref. [3]. The table also includes lar, cellular and systems effects of oxidative stress is drug-induced (anthracyclines and others) cardiolimited. An essential omission is the absence of any myopathies, subject of considerable assessment by Dr. reference to the involvement and the well-studied clinical Singal. The exclusion of CoQ again is an indefensible 10 applications of coenzyme Q in various forms of carissue. 10 diovascular diseases — a subject of great interest for the Despite the well-known high risk of cardiomyopathies readers of this publication. and, ultimately, congestive heart failure incidence associCoenzyme Q (CoQ , ubiquinone) is a naturally ated with doxorubicin (DR, adriamycin) treatment, this 10 10 occuring, fat-soluble nutrient (a quinone), with characteriscytotoxic anthracycline antibiotic is still widely included in tics that are common to vitamins and, like vitamins, is most cancer clinical regimens because of its efficacy and essential to the optimal functioning of an organism. CoQ broad-spectrum activity. 10 is a potent and versatile antioxidant that is present in Results from the mid-1970s, reviewed by Olson et al. humans and in some animals. In addition to its antioxidant [4], indicate strongly that DR produces free radicals in function, CoQ plays an indispensable role in intracellular microsomal systems and it was postulated that, because of 10 energy production. Being a vital electron and proton recycling, one DR molecule forms many free radical carrier, CoQ supports adenosine triphosphate synthesis in molecules. They are capable of causing lipid peroxidation, 10 the mitochondrial inner membrane and stabilizes cell especially at the mitochondrial level, resulting in mormembranes, thus preserving cellular integrity and function. phological as well as functional mitochondrial injury. The Most CoQ clinical research is focused on the large, end result of this injury is the clinically critical dis10 heterogeneous group of cardiovascular diseases. The first integration of the intramitochondrial bioenergetic process. report of such a clinical trial was published 30 years ago. The heart, with its high energy demand, is more suscepSince 1960, 14 international symposia have been organized tible to injuries caused by free radicals. Olson et al. [4] and the proceedings have been published. This represents a also noted that free radical scavengers attenuate DR-incollection of more than 4100 pages of technical contribuduced cardiac dysfunction, thus contributing to the accepttions on various medical and clinical aspects of CoQ . As ance of today’s well-confirmed theory for the causal 10 a result, the relationship between cardiac CoQ deinvolvement of free radicals in many pathological pro10 ficiency, cardiovascular diseases and their amelioration by cesses, ranging from neoplasia to aging, and their amelioCoQ treatment was demonstrated. ration following the administration of antioxidants. 10