Effect of antioxidants on mitochondrial function in HIV-1-related lipoatrophy: a pilot study

The Immunomodulatory Effect of Alpha-Lipoic Acid in Autoimmune Diseases

Αlpha-lipoic acid is a naturally occurring antioxidant in human body and has been widely used as an antioxidant clinically. Accumulating evidences suggested that α-lipoic acid might have immunomodulatory effects on both adaptive and innate immune systems. This review focuses on the evidences and potential targets involved in the immunomodulatory effects of α-lipoic acid. It highlights the fact that α-lipoic acid may have beneficial effects in autoimmune diseases once the immunomodulatory effects can be confirmed by further investigation.

Beyond the polymerase-γ theory: Production of ROS as a mode of NRTI-induced mitochondrial toxicity

Use of some HIV-1 nucleoside reverse transcriptase inhibitors (NRTI) is associated with severe adverse events. However, the exact mechanisms behind their toxicity has not been fully understood. Mitochondrial dysfunction after chronic exposure to specific NRTIs has predominantly been assigned to mitochondrial polymerase-γ inhibition by NRTIs. However, an increasing amount of data suggests that this is not the sole mechanism. Many NRTI induced adverse events have been linked to the incurrence of oxidative stress, although the causality of events leading to reactive oxygen species (ROS) production and their role in toxicity is unclear. In this study we show that short-term effects of first generation NRTIs, which are rarely discussed in the literature, include inhibition of oxygen consumption, decreased ATP levels and increased ROS production. Collectively these events affect fitness and longevity of C. elegans through mitohormetic signalling events. Furthermore, we demonstrate that these effects can be normalized by addition of the anti-oxidant N-acetylcysteine (NAC), which suggests that ROS likely influence the onset and severity of adverse events upon drug exposure.

Emerging role of alpha-lipoic acid in the prevention and treatment of bone loss

Osteoporosis is a chronic disease associated with decreased bone density that afflicts millions of people worldwide. Current pharmacological treatments are limited, costly, and linked to several negative side effects. These factors are driving current interest in the clinical use of naturally occurring bioactive compounds to mitigate bone loss. Alpha-lipoic acid, a potent antioxidant and essential member of mitochondrial dehydrogenases, has shown considerable promise as an antiosteoclastogenic agent due to its potent reactive oxygen species-scavenging capabilities along with a proven clinical safety record. Collectively, current data indicate that alpha-lipoic acid protects from bone loss via a 2-pronged mechanism involving inhibition of osteoclastogenic reactive oxygen species generation and upregulation of redox gene expression.

Current experience in testing mitochondrial nutrients in disorders featuring oxidative stress and mitochondrial dysfunction: rational design of chemoprevention trials

An extensive number of pathologies are associated with mitochondrial dysfunction (MDF) and oxidative stress (OS). Thus, mitochondrial cofactors termed "mitochondrial nutrients" (MN), such as α-lipoic acid (ALA), Coenzyme Q10 (CoQ10), and l-carnitine (CARN) (or its derivatives) have been tested in a number of clinical trials, and this review is focused on the use of MN-based clinical trials. The papers reporting on MN-based clinical trials were retrieved in MedLine up to July 2014, and evaluated for the following endpoints: (a) treated diseases; (b) dosages, number of enrolled patients and duration of treatment; (c) trial success for each MN or MN combinations as reported by authors. The reports satisfying the above endpoints included total numbers of trials and frequencies of randomized, controlled studies, i.e., 81 trials testing ALA, 107 reports testing CoQ10, and 74 reports testing CARN, while only 7 reports were retrieved testing double MN associations, while no report was found testing a triple MN combination. A total of 28 reports tested MN associations with "classical" antioxidants, such as antioxidant nutrients or drugs. Combinations of MN showed better outcomes than individual MN, suggesting forthcoming clinical studies. The criteria in study design and monitoring MN-based clinical trials are discussed.

Role of mitochondria in HIV infection and associated metabolic disorders: focus on nonalcoholic fatty liver disease and lipodystrophy syndrome

Highly active antiretroviral therapy (HAART) has considerably improved the prognosis of HIV-infected patients. However, prolonged use of HAART has been related to long-term adverse events that can compromise patient health such as HIV-associated lipodystrophy syndrome (HALS) and nonalcoholic fatty liver disease (NAFLD). There is consistent evidence for a central role of mitochondrial dysfunction in these pathologies. Nucleotide reverse transcriptase inhibitors (NRTIs) have been described to be mainly responsible for mitochondrial dysfunction in adipose tissue and liver although nonnucleoside transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs) have also showed mitochondrial toxicity, which is a major concern for the selection and the long-term adherence to a particular therapy. Several mechanisms explain these deleterious effects of HAART on mitochondria, and evidence points to other mechanisms beyond the “Pol-γ hypothesis.” HIV infection has also direct effects on mitochondria. In addition to the negative effects described for HIV itself and/or HAART on mitochondria, HIV-infected patients are more prone to develop a premature aging and, therefore, to present an increased oxidative state that could lead to the development of these metabolic disturbances observed in HIV-infected patients.

Glutathione homeostasis and functions: potential targets for medical interventions

Glutathione (GSH) is a tripeptide, which has many biological roles including protection against reactive oxygen and nitrogen species. The primary goal of this paper is to characterize the principal mechanisms of the protective role of GSH against reactive species and electrophiles. The ancillary goals are to provide up-to-date knowledge of GSH biosynthesis, hydrolysis, and utilization; intracellular compartmentalization and interorgan transfer; elimination of endogenously produced toxicants; involvement in metal homeostasis; glutathione-related enzymes and their regulation; glutathionylation of sulfhydryls. Individual sections are devoted to the relationships between GSH homeostasis and pathologies as well as to developed research tools and pharmacological approaches to manipulating GSH levels. Special attention is paid to compounds mainly of a natural origin (phytochemicals) which affect GSH-related processes. The paper provides starting points for development of novel tools and provides a hypothesis for investigation of the physiology and biochemistry of glutathione with a focus on human and animal health.

Potential benefits of carnitine in HIV-positive patients

Carnitine is a nonessential amino acid that has a central role in lipid peroxidation and mitochondrial metabolism. Carnitine deficiency is rare in adult human subjects who have a normal diet and no underlying chronic diseases. Studies have shown that HIV-infected patients are at increased risk of carnitine deficiency due to decreased intake, increased metabolism, gastrointestinal problems, HIV infection itself, concomitant infections, underlying disease, concomitant drugs and antiretroviral therapy. Decreased serum and muscle carnitine content was reported following antiretroviral therapy in HIV-positive patients. The beneficial effects of carnitine on the human immune system, such as prevention of CD4 cell apoptosis, was reported in these patients. Additionally, polyneuropathy, myopathy, lactic acidosis, dyslipidemia and lipodystrophy are complications of antiretroviral therapy that have been proposed to potentially be related to carnitine deficiency and mitochondrial dysfunction. Carnitine may have a significant role in improving some aspects of mitochondrial toxicity induced by an antiretroviral regimen, such as lipodystrophy. Also, there are nearly sufficient data to support the beneficial effects of carnitine in improving the symptoms of lactic acidosis following antiretroviral therapy. According to available data, it is concluded that carnitine may have beneficial effects in the treatment of antiretroviral-induced neuropathy. Most of the evidence supports carnitine supplementation as a treatment strategy rather than prophylaxis for antiretroviralinduced complications. Several studies have shown the prevalence of carnitine deficiency and its role in different aspects of infection and antiretroviral-induced complications in HIV-positive patients, but the probable beneficial effects of carnitine supplementation are not clear in this population. In this review, we have collected and categorized available evidence regarding the potential benefits of carnitine supplementation in HIV-infected individuals.

Mitochondrial impact of human immunodeficiency virus and antiretrovirals on infected pediatric patients with or without lipodystrophy

We determined the mitochondrial status of a group of HIV-infected children, some with body fat abnormalities (BFA). We included 24 controls, 16 HIV-infected untreated, 26 HIV-infected treated, 6 BFA-untreated, and 21 BFA-treated patients. Genetic, translational, and functional mitochondrial values were measured. As compared with controls, mitochondrial DNA depletion and a reduction in functionality were found in BFA groups.

Mitochondrial DNA copy number and pancreatic cancer in the alpha-tocopherol beta-carotene cancer prevention study

Diabetes, obesity, and cigarette smoke, consistent risk factors for pancreatic cancer, are sources of oxidative stress in humans that could cause mitochondrial DNA (mtDNA) damage and increase mtDNA copy number. To test whether higher mtDNA copy number is associated with increased incident pancreatic cancer, we conducted a nested case-control study in the Alpha-Tocopherol Beta Carotene Cancer Prevention (ATBC) Study cohort of male smokers, aged 50 to 69 years at baseline. Between 1992 and 2004, 203 incident cases of pancreatic adenocarcinoma occurred (follow-up: 12 years) among participants, with whole blood samples used for mtDNA extraction. For these cases and 656 controls, we calculated ORs and 95% CIs using unconditional logistic regression, adjusting for age, smoking, and diabetes history. All statistical tests were two sided. Higher mtDNA copy number was significantly associated with increased pancreatic cancer risk (highest vs. lowest mtDNA copy number quintile, OR = 1.64, 95% CI = 1.01-2.67, continuous OR = 1.14, 95% CI 1.06-1.23), particularly for cases diagnosed during the first 7 years of follow-up (OR = 2.14, 95% CI = 1.16-3.96, P(trend) = 0.01, continuous OR = 1.21, 95% CI = 1.10-1.33), but not for cases occurring during follow-up of 7 years or greater (OR = 1.14, 95% CI = 0.53-2.45, continuous OR = 1.05, 95% CI = 0.93-1.18). Our results support the hypothesis that mtDNA copy number is associated with pancreatic cancer and could possibly serve as a biomarker for pancreatic cancer development.