Lipoic acid stimulates cAMP production via the EP2 and EP4 prostanoid receptors and inhibits IFN gamma synthesis and cellular cytotoxicity in NK cells

cAMP-PKA/EPAC signaling and cancer: the interplay in tumor microenvironment

Cancer is a complex disease resulting from abnormal cell growth that is induced by a number of genetic and environmental factors. The tumor microenvironment (TME), which involves extracellular matrix, cancer-associated fibroblasts (CAF), tumor-infiltrating immune cells and angiogenesis, plays a critical role in tumor progression. Cyclic adenosine monophosphate (cAMP) is a second messenger that has pleiotropic effects on the TME. The downstream effectors of cAMP include cAMP-dependent protein kinase (PKA), exchange protein activated by cAMP (EPAC) and ion channels. While cAMP can activate PKA or EPAC and promote cancer cell growth, it can also inhibit cell proliferation and survival in context- and cancer type-dependent manner. Tumor-associated stromal cells, such as CAF and immune cells, can release cytokines and growth factors that either stimulate or inhibit cAMP production within the TME. Recent studies have shown that targeting cAMP signaling in the TME has therapeutic benefits in cancer. Small-molecule agents that inhibit adenylate cyclase and PKA have been shown to inhibit tumor growth. In addition, cAMP-elevating agents, such as forskolin, can not only induce cancer cell death, but also directly inhibit cell proliferation in some cancer types. In this review, we summarize current understanding of cAMP signaling in cancer biology and immunology and discuss the basis for its context-dependent dual role in oncogenesis. Understanding the precise mechanisms by which cAMP and the TME interact in cancer will be critical for the development of effective therapies. Future studies aimed at investigating the cAMP-cancer axis and its regulation in the TME may provide new insights into the underlying mechanisms of tumorigenesis and lead to the development of novel therapeutic strategies.

A novel approach to alpha-lipoic acid therapy in the treatment of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is a heterogenic disorder prevalent amongst patients suffering from diabetes mellitus (DM), with symptoms comprising neuropathic pain, paresthesia, and numbness in distal lower limbs. Alpha-lipoic acid (ALA) is proposed as a pathogenesis-oriented treatment option, targeting underlying causes of neural lesions such as hyperglycemia, metabolic and microvascular dysfunctions, and cellular oxidative stress. We performed a comprehensive review of controlled clinical trials demonstrating the clinical usefulness of ALA in the treatment of DPN, published in the last 5 years to determine the benefits of ALA monotherapy and combined treatments with other known antioxidants. We also investigated the differential efficacy of oral versus intravenous ALA administration. Clinical trials show the efficacy of ALA treatment, attributed to its anti-inflammatory, anti-hyperglycemic, and antioxidant properties, as well as its function in the endothelial activation and lipid metabolism parameters. ALA supplementation is associated with amelioration in nerve conduction velocity scores, clinically significant reduction of reported neuropathic pain, burning and paresthesia, as well as a decrease in serum triglycerides, improved insulin sensitivity, and quality of life.

Role of lipoic acid in multiple sclerosis

Lipoic acid (LA) is an endogenous antioxidant that exists widely in nature. Supplementation with LA is a promising approach to improve the outcomes of patients with multiple sclerosis (MS). This systematic review aimed to provide a comprehensive overview of both in vitro and in vivo studies describing the pharmacokinetics, efficacy, safety, and mechanism of LA in MS‐related experiments and clinical trials. A total of 516 records were identified by searching five databases, including PubMed, Web of Science, Embase, Scopus, and Cochrane Library. Overall, we included 20 studies reporting LA effects in cell and mouse models of MS and 12 studies reporting LA effects in patients with MS. Briefly, cell experiments revealed that LA protected neurons by inhibiting the expression of inflammatory mediators and activities of immune cells. Experimental autoimmune encephalomyelitis mouse experiments demonstrated that LA consistently reduced the number of infiltrating immune cells in the central nervous system and decreased the clinical disability scores. Patients with MS showed relatively stable Expanded Disability Status Scale scores and better walking performance with few adverse events after the oral administration of LA. Notably, heterogeneity of this evidence existed among modeling methods, LA usage, MS stage, and trial duration. In conclusion, this review provides evidence for the anti‐inflammatory and antioxidative effects of LA in both in vitro and in vivo experiments; therefore, patients with MS may benefit from LA administration. Whether LA can be a routine supplementary therapy warrants further study.

Lipoic acid modulates inflammatory responses of monocytes and monocyte-derived macrophages from healthy and relapsing-remitting multiple sclerosis patients

Multiple sclerosis (MS) is a disabling neuroinflammatory disease. Its etiology is unknown, but both oxidative stress and inflammation appear to be involved in disease pathology. Macrophages are the predominant cell type in acute inflammatory brain lesions in MS. Macrophages produce proinflammatory and toxic molecules that promote demyelination and are key players in phagocytosis/degradation of myelin sheathes. Lipoic acid (LA) is an inexpensive, endogenously produced small molecule that exhibits antioxidant and anti-inflammatory effects. Treatment with LA is protective in MS and other inflammatory diseases. To examine the mechanism(s) by which LA may attenuate inflammatory lesion activity in MS, we used healthy control and MS cells to evaluate the effects of LA on levels of inflammatory cytokines, phagocytosis and the immunomodulator cyclic adenosine monophosphate (cAMP) in monocytes and monocyte-derived macrophages (MDMs). LA treatment resulted in a generally less inflammatory phenotype of monocytes and MDMs from healthy controls, and (to a lesser degree) MS donors. LA inhibited monocyte secretion of cytokines relevant to MS in monocytes, including tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β; LA effects on secretion of these cytokines in MDMs were mixed with inhibition of TNF-α and IL-6, but stimulation of IL-1β, the latter perhaps as a result of altered macrophage polarization. LA inhibited phagocytosis in both monocytes and MDMs, and increased cAMP levels in monocytes. LA may modulate inflammatory cytokine secretion and phagocytosis via a cAMP-mediated mechanism.

A Systematic Review on the Role of Arachidonic Acid Pathway in Multiple Sclerosis

BACKGROUND & OBJECTIVE

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease characterized by destruction of oligodendrocytes, immune cell infiltration and demyelination. Inflammation plays a significant role in MS, and the inflammatory mediators such as eicosanoids, leukotrienes, superoxide radicals are involved in pro-inflammatory responses in MS. In this systematic review we tried to define and discuss all the findings of in vivo animal studies and human clinical trials on the potential association between arachidonic acid (AA) pathway and multiple sclerosis.

METHODS

A systematic literature search across Pubmed, Scopus, Embase and Cochrane database was conducted. This systematic review was performed according to PRISMA guidelines.

RESULTS

A total of 146 studies were included, of which 34 were conducted in animals, 58 in humans, and 60 studies reported the role of different compounds that target AA mediators or their corresponding enzymes/ receptors, and can have a therapeutic effect in MS. These results suggest that eicosanoids have significant roles in experimental autoimmune encephalomyelitis (EAE) and MS. The data from animal and human studies elucidated that PGI2, PGF2α, PGD2, isoprostanes, PGE2, PLA2, LTs are increased in MS. PLA2 inhibition modulates the progression of the disease. PGE1 analogues can be a useful option in the treatment of MS.

CONCLUSIONS

All studies reported the beneficial effects of COX and LOX inhibitors in MS. The hybrid compounds, such as COX-2 inhibitors/TP antagonists and 5-LOX inhibitors can be an innovative approach for multiple sclerosis treatment. Future work in MS should shed light in synthesizing new compounds targeting arachidonic acid pathway.

R-α-Lipoic Acid and 4-Phenylbutyric Acid Have Distinct Hypolipidemic Mechanisms in Hepatic Cells

The constitutive activation of the mechanistic target of rapamycin complex 1 (mTORC1) leads to the overproduction of apoB-containing triacylglycerol-rich lipoproteins in HepG2 cells. R-α-lipoic acid (LA) and 4-phenylbutyric acid (PBA) have hypolipidemic function but their mechanisms of action are not well understood. Here, we reported that LA and PBA regulate hepatocellular lipid metabolism via distinct mechanisms. The use of SQ22536, an inhibitor of adenylyl cyclase, revealed cAMP’s involvement in the upregulation of CPT1A expression by LA but not by PBA. LA decreased the secretion of proprotein convertase subtilisin/kexin type 9 (PCSK9) in the culture media of hepatic cells and increased the abundance of LDL receptor (LDLR) in cellular extracts in part through transcriptional upregulation. Although PBA induced LDLR gene expression, it did not translate into more LDLR proteins. PBA regulated cellular lipid homeostasis through the induction of CPT1A and INSIG2 expression via an epigenetic mechanism involving the acetylation of histone H3, histone H4, and CBP-p300 at the CPT1A and INSIG2 promoters.

The attenuation of the toxic effects of LPS on mouse pre-implantation development by alpha-lipoic acid

The present study was conducted to evaluate the effects of alpha-lipoic acid (ALA) on quantitative and qualitative indices of mouse embryos challenged by lipopolysaccharide (LPS). Having determined the effective concentrations of LPS (1 mg/mL) that could reduce blastocyst formation rate by around 50% and the optimal concentration of ALA (10 μM) that could attenuate the toxic effects of LPS on blastocyst formation, the following indices were defined: inner cell mass and trophectoderm cell numbers, blastocyst mitochondrial distribution, ROS and GSH levels, as well as the relative expression of Tlr-4. Nrf-2 and Tnf-RI/P-60 receptor involved in inflammatory pathways. Finally, embryos derived from the experimental and control groups were transferred to synchronized recipients and their implantation rate and post-implantation capacity were determined. Treatment with LPS resulted in an increase in intracellular ROS level (P ≤ 0.05), and remarkable decreases (P ≤ 0.05) in intracellular GSH content, mitochondrial mass, and blastocyst quality. ALA attenuated all the aforementioned negative effects of LPS. The relative expression levels of Nrf-2 and Tnf-RI/P-60 receptor (P ≤ 0.05) significantly increased in response to LPS, and treatment with ALA significantly reduced the relative expression of Tnf-RI/P-60. ALA also improved the post-implantation developmental capacity of embryos treated with LPS. In conclusion, our findings indicate that the reproductive toxicity of LPS could be overcome by ALA treatment. These effects were mainly due to the improvements made in intracellular antioxidant capacity as well as suppression of some inflammatory elements, especially the main receptor of TNF-α, the Tnf-RI/P-60, involved in induction of apoptosis. These observations have important implications for dairy farming and treatment of infertility.

Effect of alpha-lipoic acid and myoinositol on endometrial inflammasome from recurrent pregnancy loss women

PROBLEM

A significant increased expression/activation of one of the most well-characterized inflammasomes, the NAcht leucine-rich-repeat protein-3 (NALP-3), in the endometrium from idiopathic recurrent pregnancy loss women (RPL) has been previously found by our research group. We therefore, suggested this event as being one of the molecular mechanisms altering endometrial inflammatory status during early pregnancy. In the present research, we attempt to investigate whether molecules with anti-inflammatory activity, alpha-lipoic acid (ALA), and/or myoinositol affect the endometrial NALP-3 expression and activation.

METHOD OF STUDY

Women with a history of idiopathic RPL (n = 30) were included in the study and compared to a control group (n = 15). Endometrial tissues were collected by hysteroscopy during the mid-luteal phase. RPL women underwent a three-month prescription of tablets containing ALA plus myoinositol (Sinopol^® ). After treatment, hysteroscopic biopsies were repeated in RPL patients. Inflammasome expression was evaluated by immunohistochemical and Western blot analysis. NALP-3 activation was studied by quantifying the secretion of both caspase-1 and interleukin (IL)-1ß and IL-18 through ELISA. In ex vivo experiments, the effects of each molecule on endometrial inflammasome were studied.

RESULTS

Sinopol^® significantly reduced the RPL endometrial inflammasome expression and activation. ALA, but not myoinositol, significantly reduced the endometrial inflammasome expression and activity.

CONCLUSION

Our data suggest a role for ALA on RPL inflammasome. Understanding the mechanisms involved in RPL and the observation that specific molecules are able to interfere with such complex at the endometrium might provide new rational design approaches to a personalized evaluation of endometrial status and, ultimately, a targeted medicine.

Alpha-lipoic acid (ALA) supplementation effect on glycemic and inflammatory biomarkers: A Systematic Review and meta- analysis

BACKGROUND & AIMS

Several randomized clinical trials (RCTs) have investigated the effect of Alpha - Lipoic Acid (ALA) supplementation on metabolic parameters, with conflicting results. Therefore, the present study assessed the effect of ALA on some glycemic and inflammatory parameters.

METHODS

A comprehensive literature search was conducted up from inception to July 2018 on PubMed, Scopus, Cochrane databases, Google Scholar, ProQuest, Web of Science, and Embase. From among eligible trials, 41 articles were selected for the meta-analysis. Two reviewers independently assessed the risk of bias and extracted data from the included studies. Meta-analyses using the random-effects model were performed to analyze the data.

RESULTS

Based on the Cochrane risk of bias tool, 19 articles had a good quality, 16 trials had a poor quality and 6 trials had a fair quality. The results demonstrated the significant effect of ALA on Fasting Blood Sugar (FBS) (weighted mean difference (WMD)) = -6.57, 95% confidence interval (CI: -11.91 to -1.23, P = 0.016), Hemoglobin A1c (HbA1c) (WMD = -0.35, 95% CI: -0.55 to -0.15, P = 0.004), Tumor Necrosis Factor Alpha (TNF-α) (WMD = -1.57, 95% CI: -2.29 to -0.85, P < 0.05), Interleukin 6 levels (IL-6) (WMD = -1.15, 95% CI: -1.58 to -0.72, P < 0.001), and C-reactive protein (CRP) (WMD = -0.31, 95% CI: -0.47 to -0.16, P > 0.001). No effect was detected for ALA on insulin and the homeostatic model assessment of insulin resistance (HOMA-IR).

CONCLUSIONS

These findings suggest that ALA is a viable supplement to improve some of the glycemic and inflammatory biomarkers.

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.

α-Lipoic Acid Vaginal Administration Contrasts Inflammation and Preterm Delivery in Rats

α-Lipoic acid (ALA) is a safe natural molecule involved in the immunomodulation of many physiological processes. Orally administered ALA has been reported to treat several inflammatory pathologies and support pregnancy. Our study aimed at testing ALA vaginal administration in female Wistar rats evaluating its tissue distribution (experiment I), impact on implantation process (experiment II), and effectiveness in contrasting induced preterm birth (experiment III). In experiment I, rats were intravaginally treated with 50 mg/kg or 500 mg/kg ALA, or with a physiologic solution, for 4 days. α-Lipoic acid distribution in uterus and cervical tissues was evaluated by immunohistochemical analyses. In experiment II, rats received intravaginally the above treatments for 5 days, then they were mated and, if pregnant, included in the experiment to evaluate both implantation rate and the content of implantation mediators in uterus tissues. In experiment III, pregnant rats were pretreated with placebo or with vaginal ALA for 4 days and then induced to delivery with mifepristone plus PGE2 on the 19th day of pregnancy. The delivery time was recorded, and the messenger RNA (mRNA) levels of pro-inflammatory cytokines were detected in the uterine tissues by real-time polymerase chain reaction. Immunohistochemistry was also performed. Results showed that vaginal ALA was well absorbed and distributed. The treatment did not affect the implantation process and was able to significantly revert mifepristone plus prostaglandin E2 effects, delaying the timing of delivery and significantly decreasing mRNA synthesis and release of pro-inflammatory cytokines. We provide for the first time new information on vaginal ALA use, even during pregnancy, opening a perspective for further studies.

Early alpha-lipoic acid therapy protects from degeneration of the inner retinal layers and vision loss in an experimental autoimmune encephalomyelitis-optic neuritis model

Background

In multiple sclerosis (MS), neurodegeneration is the main reason for chronic disability. Alpha-lipoic acid (LA) is a naturally occurring antioxidant which has recently been demonstrated to reduce the rate of brain atrophy in progressive MS. However, it remains uncertain if it is also beneficial in the early, more inflammatory-driven phases. As clinical studies are costly and time consuming, optic neuritis (ON) is often used for investigating neuroprotective or regenerative therapeutics. We aimed to investigate the prospect for success of a clinical ON trial using an experimental autoimmune encephalomyelitis-optic neuritis (EAE-ON) model with visual system readouts adaptable to a clinical ON trial.

Methods

Using an in vitro cell culture model for endogenous oxidative stress, we compared the neuroprotective capacity of racemic LA with the R/S-enantiomers and its reduced form. In vivo, we analyzed retinal neurodegeneration using optical coherence tomography (OCT) and the visual function by optokinetic response (OKR) in MOG_35–55-induced EAE-ON in C57BL/6J mice. Ganglion cell counts, inflammation, and demyelination were assessed by immunohistological staining of retinae and optic nerves.

Results

All forms of LA provided equal neuroprotective capacities in vitro. In EAE-ON, prophylactic LA therapy attenuated the clinical EAE score and prevented the thinning of the inner retinal layer while therapeutic treatment was not protective on visual outcomes.

Conclusions

A prophylactic LA treatment is necessary to protect from visual loss and retinal thinning in EAE-ON, suggesting that a clinical ON trial starting therapy after the onset of symptoms may not be successful.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1111-y) contains supplementary material, which is available to authorized users.

Lipoic Acid Stimulates cAMP Production in Healthy Control and Secondary Progressive MS Subjects

Lipoic acid (LA) exhibits antioxidant and anti-inflammatory properties; supplementation reduces disease severity and T lymphocyte migration into the central nervous system in a murine model of multiple sclerosis (MS), and administration in secondary progressive MS (SPMS) subjects reduces brain atrophy compared to placebo. The mechanism of action (MOA) of LA's efficacy in suppression of MS pathology is incompletely understood. LA stimulates production of the immunomodulator cyclic AMP (cAMP) in vitro. To determine whether cAMP could be involved in the MOA of LA in vivo, we performed a clinical trial to examine whether LA stimulates cAMP production in healthy control and MS subjects, and whether there are differences in the bioavailability of LA between groups. We administered 1200 mg of oral LA to healthy control, relapsing remitting MS (RRMS) and SPMS subjects, and measured plasma LA and cAMP levels in peripheral blood mononuclear cells (PBMCs). There were no significant differences between the groups in pharmacokinetic (PK) parameters. Healthy and SPMS subjects had increased cAMP at 2 and 4 h post-LA treatment compared to baseline, while RRMS subjects showed decreases in cAMP. Additionally, plasma concentrations of prostaglandin E2 (PGE₂, a known cAMP stimulator) were significantly lower in female RRMS subjects compared to female HC and SPMS subjects 4 h after LA ingestion. These data indicate that cAMP could be part of the MOA of LA in SPMS, and that there is a divergent response to LA in RRMS subjects that may have implications in the efficacy of immunomodulatory drugs. This clinical trial, "Defining the Anti-inflammatory Role of Lipoic Acid in Multiple Sclerosis," NCT00997438, is registered at https://clinicaltrials.gov/ct2/show/record/NCT00997438 .

The regulation of FGF21 gene expression by metabolic factors and nutrients

Fibroblast growth factor 21 (FGF21) gene expression is altered by a wide array of physiological, metabolic, and environmental factors. Among dietary factors, high dextrose, low protein, methionine restriction, short-chain fatty acids (butyric acid and lipoic acid), and all-trans-retinoic acid were repeatedly shown to induce FGF21 expression and circulating levels. These effects are usually more pronounced in liver or isolated hepatocytes than in adipose tissue or isolated fat cells. Although peroxisome proliferator-activated receptor α (PPARα) is a key mediator of hepatic FGF21 expression and function, including the regulation of gluconeogenesis, ketogenesis, torpor, and growth inhibition, there is increasing evidence of PPARα-independent transactivation of the FGF21 gene by dietary molecules. FGF21 expression is believed to follow the circadian rhythm and be placed under the control of first order clock-controlled transcription factors, retinoic acid receptor-related orphan receptors (RORs) and nuclear receptors subfamily 1 group D (REV-ERBs), with FGF21 rhythm being anti-phase to REV-ERBs. Key metabolic hormones such as glucagon, insulin, and thyroid hormone have presumed or clearly demonstrated roles in regulating FGF21 transcription and secretion. The control of the FGF21 gene by glucagon and insulin appears more complex than first anticipated. Some discrepancies are noted and will need continued studies. The complexity in assessing the significance of FGF21 gene expression resides in the difficulty to ascertain (i) when transcription results in local or systemic increase of FGF21 protein; (ii) if FGF21 is among the first or second order genes upregulated by physiological, metabolic, and environmental stimuli, or merely an epiphenomenon; and (iii) whether FGF21 may have some adverse effects alongside beneficial outcomes.

Dimethyl fumarate activates the prostaglandin EP2 receptor and stimulates cAMP signaling in human peripheral blood mononuclear cells

Dimethyl fumarate (DMF) was recently approved by the FDA for the treatment of relapsing remitting MS. The pathology of MS is a result of both immune dysregulation and oxidative stress induced damage, and DMF is believed to have therapeutic effects on both of these processes. However, the mechanisms of action of DMF are not fully understood. To determine if DMF is able to activate signaling cascades that affect immune dysregulation, we treated human peripheral blood mononuclear cells with DMF. We discovered that DMF stimulates cyclic adenosine monophosphate (cAMP) production after 1 min treatment in vitro. cAMP is a small molecule second messenger that has been shown to modulate immune response. Using pharmacological inhibitors, we determined that adenylyl cyclase mediates DMF induced cAMP production; DMF activated the prostaglandin EP2 receptor to produce cAMP. This response was not due to increased endogenous production of prostaglandin E2 (PGE2), but was enhanced by addition of exogenous PGE2. Furthermore, we determined that the bioactive metabolite of DMF, monomethyl fumarate (MMF), also stimulates cAMP production. These novel findings suggest that DMF may provide protection against MS by inhibiting immune cell function via the cAMP signaling pathway.

Mapping the response of human fibroblast growth factor 21 (FGF21) promoter to serum availability and lipoic acid in HepG2 hepatoma cells

The hormone-like polypeptide, fibroblast growth factor 21 (FGF21), is a major modulator of lipid and glucose metabolism and an exploratory treatment strategy for obesity related metabolic disorders. The costs of recombinant FGF21 and mode of delivery by injection are important constraints to its wide therapeutic use. The stimulation of endogenous FGF21 production through diet is being explored as an alternative approach. To that end, we examined the mechanism(s) by which serum manipulation and lipoic acid (a dietary activator of FGF21) induce FGF21 in human hepatocellular carcinoma HepG2 cells. Serum withdrawal markedly induced FGF21 mRNA levels (88 fold) and FGF21 secreted in the media (19 fold). Lipoic acid induced FGF21 mRNA 7 fold above DMSO-treated control cells and FGF21 secretion 3 fold. These effects were several-fold greater than those of PPARα agonist, Wy14643, which failed to induce FGF21 above and beyond the induction seen with serum withdrawal. The use of transcription inhibitor, actinomycin D, revealed that de novo mRNA synthesis drives FGF21 secretion in response to serum starvation. Four previously unrecognized loci in FGF21 promoter were nucleosome depleted and enriched in acetylated histone H3 revealing their role as transcriptional enhancers and putative transcription factor binding sites. FGF21 did not accumulate to a significant degree in induced HepG2 cells, which secreted FGF21 time dependently in media. We conclude that lipoic acid cell signaling connects with the transcriptional upregulation of FGF21 and it may prove to be a safe and affordable means to stimulate FGF21 production.

α-Lipoic acid as a triglyceride-lowering nutraceutical

Considering the current obesity epidemic in the United States (>100 million adults are overweight or obese), the prevalence of hypertriglyceridemia is likely to grow beyond present statistics of ∼30% of the population. Conventional therapies for managing hypertriglyceridemia include lifestyle modifications such as diet and exercise, pharmacological approaches, and nutritional supplements. It is critically important to identify new strategies that would be safe and effective in lowering hypertriglyceridemia. α-Lipoic acid (LA) is a naturally occurring enzyme cofactor found in the human body in small quantities. A growing body of evidence indicates a role of LA in ameliorating metabolic dysfunction and lipid anomalies primarily in animals. Limited human studies suggest LA is most efficacious in situations where blood triglycerides are markedly elevated. LA is commercially available as dietary supplements and is clinically shown to be safe and effective against diabetic polyneuropathies. LA is described as a potent biological antioxidant, a detoxification agent, and a diabetes medicine. Given its strong safety record, LA may be a useful nutraceutical, either alone or in combination with other lipid-lowering strategies, when treating severe hypertriglyceridemia and diabetic dyslipidemia. This review examines the current evidence regarding the use of LA as a means of normalizing blood triglycerides. Also presented are the leading mechanisms of action of LA on triglyceride metabolism.

[Antioxidant use as dietary therapy in patients with multiple sclerosis]

INTRODUCTION

Multiple sclerosis is an immune-mediated disease that produces chronic inflammation and neural degeneration. The disease progresses with acute attacks that result in myelin inflammation. This in turn increases oxidative stress and favors the appearance of reactive oxygen species. Reactive oxygen species damage neural cells causing apoptosis. The etiology of multiple sclerosis remains unknown and current therapy is aggressive and expensive. Recently, complementary and alternative medicine therapies have been proposed to control pathogenesis and symptoms of this disease. It is believed that these therapies help slow the progression of multiple sclerosis and improve survival.

METHODS

We conducted a MEDLINE/PubMed search using the following MeSH terms: diet, multiple sclerosis, antioxidants. We selected the main articles containing multiple sclerosis and diet.

RESULTS

We analyzed three case control studies that evaluated different dietary approaches in multiple sclerosis. For this review, we also included five experimental studies that studied the efficacy of lipoic acid in humans and rodents in diseases like multiple sclerosis, experimental autoimmune encephalomyelitis, and breast cancer.

Effect of SP-A/B in lipoic acid on acute paraquat poisoning

BACKGROUND

This study was undertaken to observe the concentration of SP-A/B and the pulmonary surfactant in the lung tissue of rats with acute lung injury/acute respiratory distress syndrome caused by paraquat poisoning after the treatment of metabolic antioxidant-lipoic acid and whether its influence was related to TNF-α.

METHODS

Sixty-six male Sprage-Dawley rats were randomly divided into three groups: normal control group (NS group), 6 rats; paraquat poisoning group (PQ group), 30 rats; and paraquat+lipoic acid treatment group (LA group), 30 rats. The rats in the PQ and LA groups were subdivided into 3-, 6-, 12-, 24-, 48-hour subgroups, with 6 rats in each group. After the rats were sacrificed, lung tissue from the same part was taken from the rats. After HE staining, histological changes were observed in the tissue under a light microscope. Lung tissue was also taken to test the levels of superoxide dismutase (SOD) and malondialdehyde (MDA). Whole blood (0.8 mL) without anticoagulant was drawn from the tail vein of rats for the determination of the TNF-α level. The total RNA of the lung tissue was collected, and the Rt-PCR method was used to measure the levels of SP-A and SP-B mRNA.

RESULTS

HE staining showed that histopathological changes were milder in the LA group than in the PQ group. There were significant differences in MDA and SOD levels between different intervals both in intergroups and intragroups except the 3-hour subgroup (P<0.01). Likewise, the significant differences in the levels of TNF-α were also present between the three groups and between different intervals (P<0.01). The significant differences in SP-A mRNA and SP-B mRNA amplification ratio were seen between the three groups at the same intervals (P<0.01), but the differences between different intervals in the PQ group were statistically significant (P<0.05). The differences between different intervals in the LA group were statistically significant (P<0.01).

CONCLUSION

Lipoic acid in acute paraquat poisoning could diminish lung tissue damage by regulating directly tumor necrosis factor and indirectly the content of pulmonary surfactant so as to reduce pulmonary edema, improve lung compliance, and finally protect lung tissues.

Alpha lipoic acid attenuates inflammatory response during extracorporeal circulation

Aim

Extracorporeal circulation (ECC) of blood during cardiopulmonary surgery has been shown to stimulate various pro-inflammatory molecules such as cytokines and chemokines. The biochemical oxidation/reduction pathways of a-lipoic acid suggest that it may have antioxidant properties.

Methods

In this study we aimed to evaluate only patients with coronary heart disease and those planned for coronary artery bypass graft operation. Blood samples were obtained from the patients before the operation (P1) and one (P2), four (P3), 24 (P4) and 48 hours (P5) after administration of a-lipoic acid (LA). The patients were divided into two groups, control and LA treatment group. Levels of interleukin-6 (IL-6) and -8 (IL-8), complement 3 (C3) and 4 (C4), anti-streptolysin (ASO), C-reactive protein (CRP) and haptoglobin were assessed in the blood samples.

Results

Cytokine IL-6 and IL-8 levels were significantly higher after surgery. Compared with the control groups, LA significantly decreased IL-6 and IL-8 levels in a time-dependent manner. CRP levels did not show significant variation in the first three time periods. CRP levels were higher after surgery, especially in the later periods. These results demonstrate that CRP formation depends on cytokine release. C3 and C4 levels were significantly higher after surgery than in the pre-operative period. LA treatment decreased C3 and C4 levels. Therefore, LA administration may be useful for the treatment of diseases and processes where excessive cytokine release could cause oxidative damage.

Conclusions

Our findings suggest a possible benefit of using LA during cardiac surgery to reduce cytokine levels.

Does lipoic acid consumption affect the cytokine profile in multiple sclerosis patients: a double-blind, placebo-controlled, randomized clinical trial

BACKGROUND

A limited amount of data exists regarding the effect of lipoic acid (LA), an oral antioxidant supplement, on cytokine profiles among multiple sclerosis (MS) patients.

OBJECTIVE

We aimed to assess the effect of daily consumption of LA on the cytokine profiles in MS patients.

METHODS

In this double-blind, placebo-controlled, randomized clinical trial, 52 relapsing-remitting MS patients with an age range of 18-50 years were recruited into 2 groups: LA consumption (1,200 mg/day) or placebo. Patients followed their prescribed supplements for 12 weeks. Fasting blood samples for cytokine profile measurement were collected at baseline and after the intervention. Anthropometric parameters were measured based on the standard guidelines.

RESULTS

INF-γ, ICAM-1, TGF-β and IL-4 were significantly reduced in the LA group compared to the placebo group [(INF-γ: 0.82 ± 0.2 vs. 0.2 ± 0.2 pg/ml, p < 0.0001), (ICAM-1: 20.2 ± 9.4 vs. 8 ± 10 ng/ml, p = 0.0001), (TGF-β: 103.1 ± 20.2 vs. 54.9 ± 26 ng/ml, p < 0.0001) and (IL-4: 0.1 ± 0.1 vs. 1.02 ± 1.7 ng/ml, p = 0.0112)]. No significant changes in TNF-α, IL-6, EDSS and MMP-9 were found between the LA and placebo groups (p = 0.6, p = 0.8, p = 0.09 and p = 0.8, respectively).

CONCLUSION

The results suggested that consumption of 1,200 mg LA per day beneficially affects several inflammatory cytokines including INF-γ, ICAM-1 TGF-β and IL-4. Further investigations are needed to verify the beneficial role of LA on other cytokine profiles among MS patients.

Targeting G protein coupled receptor-related pathways as emerging molecular therapies

G protein coupled receptors (GPCRs) represent the most important targets in modern pharmacology because of the different functions they mediate, especially within brain and peripheral nervous system, and also because of their functional and stereochemical properties. In this paper, we illustrate, via a variety of examples, novel advances about the GPCR-related molecules that have been shown to play diverse roles in GPCR pathways and in pathophysiological phenomena. We have exemplified how those GPCRs’ pathways are, or might constitute, potential targets for different drugs either to stimulate, modify, regulate or inhibit the cellular mechanisms that are hypothesized to govern some pathologic, physiologic, biologic and cellular or molecular aspects both in vivo and in vitro. Therefore, influencing such pathways will, undoubtedly, lead to different therapeutical applications based on the related pharmacological implications. Furthermore, such new properties can be applied in different fields. In addition to offering fruitful directions for future researches, we hope the reviewed data, together with the elements found within the cited references, will inspire clinicians and researchers devoted to the studies on GPCR’s properties.

Influence of antioxidant complex on the adhesion of leukocytes in chronic venous insufficiency of lower limbs in rats

OBJECTIVES

In this study, we have evaluated the influence of antioxidant complex (AOC) (dihydroquercetin and lipoic acid) on pool of nonadhesive leukocytes and leukocytes with low and high adhesion in chronic venous insufficiency (CVI) of lower limbs in rats.

MATERIALS AND METHODS

Model of CVI of lower limbs was created by blood flow restriction in caudal vena cava. AOC was administered at 100 mg/kg b.w./day for 14 days p.o. The venous pressure in vena cava and adhesion of leukocytes were estimated on the 14th day of the experiment.

RESULTS

On the 14th day, the venous pressure in groups of animals (experimental and control) was in 2.7-2.9-fold higher. In the control group, the significant increase of leukocytes pool with high adhesion was detected. Intragastric administration of AOC reduced the number of leukocytes with high adhesion and increased the number of nonadhesive leukocytes and leukocytes with a low adhesion.

CONCLUSIONS

Model of CVI of lower limb is accompanied by increased venous pressure and raised adhesion activity of leukocytes. Administration of AOC for 14 days reduces the adhesive activity of leukocytes.

Effects of Zuogui Pill () and Yougui Pill () on the expression of brain-derived neurotrophic factor and cyclic adenosine monophosphate/protein kinase A signaling transduction pathways of axonal regeneration in model rats with experimental autoimmune encephalomyelitis

OBJECTIVE

To study the effects of Zuogui Pill (, ZGP) and Yougui Pill (, YGP) on the expressions of brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling of axonal regeneration in the Lewis rats with experimental autoimmune encephalomyelitis (EAE), in order to explore the possible mechanism of ZGP and YGP on promoting axonal regeneration.

METHODS

The rats were randomly divided into normal control (NC), model (MO), prednisone acetate (PA), ZGP and YGP groups. The EAE model of rat was established by injecting antigen containing myelin basic protein (MBP)68-86. The brain and spinal cord were harvested on the 14th and 28th day post-immunization (PI), the protein and mRNA expression of BDNF and PKA in the brain and spinal cord of rats were detected by Western blot analysis and real-time quantitative polymerase chain reaction (PCR), and the cAMP levels were detected by using enzyme-immunoassay method.

RESULTS

(1) On the 28th day PI, the mRNA expression of BDNF in brain white matter and spinal cord of rats in ZGP and YGP groups were up-regulated, especially in YGP group (P<0.05 or P<0.01). (2) On the 14th day PI, the cAMP levels in brain white matters significantly increased in PA and YGP groups compared with MO group (P<0.05 or P<0.01), and the cAMP level in YGP group was higher than that in ZGP group (P<0.05). The cAMP level in spinal cord also significantly increased in YGP group compared with MO, PA and ZGP groups, respectively (P<0.01). (3) On the 14th day PI, the PKA expression in spinal cord of rats in ZGP group was significantly decreased compared with MO and YGP groups, respectively (P<0.05). (4) On the 28th day PI, there was a positive correlation between cAMP and PKA expression in the brain white matter of YGP rats.

CONCLUSIONS

The results suggest that ZGP and YGP may promote axonal regeneration by modulating cAMP/PKA signal transduction pathway, but the targets of molecular mechanism of ZGP may be different from those of YGP.

α-Tocopherol (vitamin E) stimulates cyclic AMP production in human peripheral mononuclear cells and alters immune function

α-Tocopherol, the most biologically active member of the vitamin E family of fat soluble compounds, exhibits both antioxidant and anti-inflammatory properties. However, its mechanisms of action are not fully understood. Here, we show that, unlike other antioxidants, α-tocopherol stimulates the production of cyclic adenosine monophosphate (cAMP). Inhibitor studies demonstrate that the prostaglandin EP2 and EP4 receptors and adenylyl cyclases mediate the effects of α-tocopherol on cAMP production. Additionally, we show that α-tocopherol attenuates pro-inflammatory cytokine and chemokine production. This study provides novel evidence that α-tocopherol stimulates cAMP signaling, suggesting a mechanism of action for the immunomodulatory effects of vitamin E.

The Regulatory Effect of Liuwei Dihuang Pills on Cytokines in Mice with Experimental Autoimmune Encephalomyelitis

The regulatory effect of Liuwei Dihuang Pills (LDP) was studied on cytokines in mice with experimental autoimmune encephalomyelitis (EAE), a model for human multiple sclerosis (MS), induced by immunization with MOG35-55 and complete Freund's adjuvant (CFA) supplemented with pertussis toxin (PTX). LDP was administrated orally for 40 days, and prednisone acetate (PA) was used as a control. The pathological changes in the spinal cords of mice were observed by light microscope with hematoxylin-eosin (HE) staining and transmission electron microscope (TEM). The protein and mRNA expression of tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta (TGF-β) in the spinal cords were assessed by immunohistochemistry and RT-PCR assay, and the cyclic adenosine monophosphate (cAMP) in mice plasma was measured by radioimmunoassay (RIA) on days 12, 25 and 40 post-immunization (PI). The results showed that inflammatory cells, demyelination and axonal loss were reduced, and that the protein and mRNA expression of TNF-α and the ratio of TNF-α/TGF-β were obviously decreased, to different extents. However, the levels of cAMP were enhanced in LDP-treated groups. These findings suggested that LDP regulates the cytokine balance in favor of T helper 1 (Th1)/regulatory T (Treg) cells, which depend on enhancement of cAMP levels. LDP has a potential role in the treatment of MS and other demyelinating diseases of the central nervous system.

The molecular basis of nutritional intervention in multiple sclerosis: a narrative review

It is commonly accepted that nutrition is one of the possible environmental factors involved in the pathogenesis of multiple sclerosis (MS), but its role as complementary MS treatment is unclear and largely disregarded. At present, MS therapy is not associated to a particular diet, probably due to lack of information on the effects of nutrition on the disease. To overcome the distrust of the usefulness of dietary control in MS and to encourage nutritional interventions in the course of the disease, it is necessary to assess the nature and the role of bioactive dietary molecules and their targets, and establish how a dietary control can influence cell metabolism and improve the wellness of MS patients. The aim of this review is to provide a rationale for a nutritional intervention in MS by evaluating at the molecular level the effects of dietary molecules on the inflammatory and autoimmune processes involved in the disease. Present data reveal that healthy dietary molecules have a pleiotropic role and are able to change cell metabolism from anabolism to catabolism and down-regulate inflammation by interacting with enzymes, nuclear receptors and transcriptional factors. The control of gut dysbiosis and the combination of hypo-caloric, low-fat diets with specific vitamins, oligoelements and dietary integrators, including fish oil and polyphenols, may slow-down the progression of the disease and ameliorate the wellness of MS patients.

Inhibitory effect of α-lipoic acid on platelet aggregation is mediated by PPARs

Peroxisome proliferator-activated receptors (PPARs) isoforms (α, β/δ, and γ are present in human platelets, and activation of PPARs inhibits platelet aggregation. α-Lipoic acid (ALA), occurring naturally in human food, has been reported to exhibit an antiplatelet activity. However, the mechanisms underlying ALA-mediated inhibition of platelet aggregation remain unknown. The aim of this study was to investigate whether the antiplatelet activity of ALA is mediated by PPARs. ALA itself significantly induced PPARα/γ activation in platelets and increased intracellular amounts of PPARα/γ by blocking PPARα/γ secretion from arachidonic acid (AA)-activated platelets. Moreover, ALA significantly inhibited AA-induced platelet aggregation, Ca(2+) mobilization, and cyclooxygenase-1 (COX-1) activity, but increased cyclic AMP production in rabbit washed platelets. Importantly, ALA also enhanced interaction of PPARα/γ with protein kinase Cα (PKCα) and COX-1 accompanied by an inhibition of PKCα activity in resting and AA-activated platelets. However, the above effects of ALA on platelets were markedly reversed by simultaneous addition of selective PPARα antagonist (GW6471) or PPARγ antagonist (GW9662). Taken together, the present study provides a novel mechanism by which ALA inhibition of platelet aggregation is mediated by PPARα/γ-dependent processes, which involve interaction with PKCα and COX-1, increase of cyclic AMP formation, and inhibition of intracellular Ca(2+) mobilization.

May diet and dietary supplements improve the wellness of multiple sclerosis patients? A molecular approach

Multiple sclerosis is a complex and multifactorial neurological disease, and nutrition is one of the environmental factors possibly involved in its pathogenesis. At present, the role of nutrition is unclear, and MS therapy is not associated to a particular diet. MS clinical trials based on specific diets or dietary supplements are very few and in some cases controversial. To understand how diet can influence the course of MS and improve the wellness of MS patients, it is necessary to identify the dietary molecules, their targets and the molecular mechanisms involved in the control of the disease. The aim of this paper is to provide a molecular basis for the nutritional intervention in MS by evaluating at molecular level the effect of dietary molecules on the inflammatory and autoimmune processes involved in the disease.

Lipoic acid stimulates cAMP production via G protein-coupled receptor-dependent and -independent mechanisms

Lipoic acid (LA) is a naturally occurring fatty acid that exhibits anti-oxidant and anti-inflammatory properties and is being pursued as a therapeutic for many diseases including multiple sclerosis, diabetic polyneuropathy and Alzheimer's disease. We previously reported on the novel finding that racemic LA (50:50 mixture of R-LA and S-LA) stimulates cAMP production, activates prostanoid EP2 and EP4 receptors and adenylyl cyclases (AC), and suppresses activation and cytotoxicity in NK cells. In this study, we present evidence that furthers our understanding of the mechanisms of action of LA. Using various LA derivatives, such as dihydrolipoic acid (DHLA), S,S-dimethyl lipoic acid (DMLA) and lipoamide (LPM), we discovered that only LA is capable of stimulating cAMP production in NK cells. Furthermore, there is no difference in cAMP production after stimulation with either R-LA, S-LA or racemic LA. Competition and synergistic studies indicate that LA may also activate AC independent of the EP2 and EP4 receptors. Pretreatment of PBMCs with KH7 (a specific peptide inhibitor of soluble AC) and the calcium inhibitor (Bapta) prior to LA treatment resulted in reduced cAMP levels, suggesting that soluble AC and calcium signaling mediate LA stimulation of cAMP production. In addition, pharmacological inhibitor studies demonstrate that LA also activates other G protein-coupled receptors, including histamine and adenosine but not the β-adrenergic receptors. These novel findings provide information to better understand the mechanisms of action of LA, which can help facilitate the use of LA as a therapeutic for various diseases.

Lipoic acid attenuates inflammation via cAMP and protein kinase A signaling

Background

Abnormal regulation of the inflammatory response is an important component of diseases such as diabetes, Alzheimer's disease and multiple sclerosis (MS). Lipoic acid (LA) has been shown to have antioxidant and anti-inflammatory properties and is being pursued as a therapy for these diseases. We first reported that LA stimulates cAMP production via activation of G-protein coupled receptors and adenylyl cyclases. LA also suppressed NK cell activation and cytotoxicity. In this study we present evidence supporting the hypothesis that the anti-inflammatory properties of LA are mediated by the cAMP/PKA signaling cascade. Additionally, we show that LA oral administration elevates cAMP levels in MS subjects.

Methodology/Principal Findings

We determined the effects of LA on IL-6, IL-17 and IL-10 secretion using ELISAs. Treatment with 50 µg/ml and 100 µg/ml LA significantly reduced IL-6 levels by 19 and 34%, respectively, in T cell enriched PBMCs. IL-17 levels were also reduced by 35 and 50%, respectively. Though not significant, LA appeared to have a biphasic effect on IL-10 production. Thymidine incorporation studies showed LA inhibited T cell proliferation by 90%. T-cell activation was reduced by 50% as measured by IL-2 secretion. Western blot analysis showed that LA treatment increased phosphorylation of Lck, a downstream effector of protein kinase A. Pretreatment with a peptide inhibitor of PKA, PKI, blocked LA inhibition of IL-2 and IFN gamma production, indicating that PKA mediates these responses. Oral administration of 1200 mg LA to MS subjects resulted in increased cAMP levels in PBMCs four hours after ingestion. Average cAMP levels in 20 subjects were 43% higher than baseline.

Conclusions/Significance

Oral administration of LA in vivo resulted in significant increases in cAMP concentration. The anti-inflammatory effects of LA are mediated in part by the cAMP/PKA signaling cascade. These novel findings enhance our understanding of the mechanisms of action of LA.

Antiplatelet activity of alpha-lipoic acid

Alpha-lipoic acid (ALA) is often used as a dietary supplement to prevent and treat chronic diseases associated with excessive oxidative stress. The aim of this study was to investigate the mechanisms of the antiplatelet activity of ALA. ALA significantly inhibited collagen-induced platelet aggregation, thromboxane B(2) (TXB(2)) formation, Ca(2+) mobilization, and protein kinase Calpha (PKCalpha) activation, but ALA itself increased cyclic AMP formation in rabbit washed platelets. However, the effects of ALA on the above platelet responses were markedly reversed by the addition of 2'5'-ddAdo, an adenylate cyclase inhibitor. Additionally, increased reactive oxygen species (ROS) formation and cyclooxygenase-1 activity stimulated by arachidonic acid were inhibited by ALA. In conclusion, we demonstrated that ALA possesses an antiplatelet activity, which may be associated with an elevation of cyclic AMP formation, involving subsequent inhibition of TXA(2), Ca(2+) mobilization, and PKCalpha-mediated pathways. Moreover, inhibition of ROS formation and increase of platelet membrane fluidity may also involve its actions.

Complementary and alternative medicine for the treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic disabling disease of the CNS that affects people during early adulthood. Despite several US FDA-approved medications, the treatment options in MS are limited. Many people with MS explore complementary and alternative medicine (CAM) treatments to help control their MS and treat their symptoms. Surveys suggest that up to 70% of people with MS have tried one or more CAM treatment for their MS. People with MS using CAM generally report deriving some benefit from the therapies. The CAM therapies most frequently used include diet, omega-3 fatty acids and antioxidants. There is very limited research evaluating the safety and effectiveness of CAM in MS. The most promising among CAM therapies that warrant further investigation are a low-fat diet, omega-3 fatty acids, lipoic acid and vitamin D supplementation as potential anti-inflammatory and neuroprotective agents in both relapsing and progressive forms of MS. There is very limited research evaluating the safety and effectiveness of CAM in MS. However, in recent years, the NIH and the National MS Society have been actively supporting the research in this very important area.

Prostaglandins in pathogenesis and treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) characterized by inflammation, demyelination, axonal loss, and gliosis. The inflammatory lesions are manifested by a large infiltration and a heterogeneous population of cellular and soluble mediators of the immune system, such as T cells, B cells, macrophages, and microglia, as well as a broad range of cytokines, chemokines, antibodies, complement, and other toxic substances. Prostaglandins (PGs) are arachidonic acid-derived autacoids that have a role in the modulation of many physiological systems including the CNS, respiratory, cardiovascular, gastrointestinal, genitourinary, endocrine, and immune systems. PG production is associated with inflammation, a major feature in MS that is characterized by the loss of myelinating oligodendrocytes in the CNS. With respect to the role of PGs in the induction of inflammation, they can be effective mediators in the pathophysiology of MS. Thus use of agonists or antagonists of PG receptors may be considered as a new therapeutic protocol in MS. In this review, we try to clarify the role of PGs in immunopathology and treatment of MS.

Pharmacokinetic study of lipoic acid in multiple sclerosis: comparing mice and human pharmacokinetic parameters

Lipoic acid is a natural antioxidant available as an oral supplement from a number of different manufacturers. Lipoic acid administered subcutaneously is an effective therapy for murine experimental autoimmune encephalomyelitis, a model of multiple sclerosis. The aim of this study was to compare serum lipoic acid levels with oral dosing in patients with multiple sclerosis with serum levels in mice receiving subcutaneous doses of lipoic acid. We performed serum pharmacokinetic studies in patients with multiple sclerosis after a single oral dose of 1200 mg lipoic acid. Patients received one of the three different racemic formulations randomly: tablet (Formulation A) and capsules (Formulations B and C). Mice pharmacokinetic studies were performed with three different subcutaneous doses (20, 50 and 100 mg/kg racemic lipoic acid). The pharmacokinetic parameters included Maximum Serum Concentrations (C(max) in microg/ml) and area under the curve (0-infinity) (AUC ( 0-infinity) in microg*min/ml). We found mean C(max) and AUC (0-infinity) in patients with multiple sclerosis as follows: group A (N = 7) 3.8 +/- 2.6 and 443.1 +/- 283.9; group B (N = 8) 9.9 +/- 4.5 and 745.2 +/- 308.7 and group C (N = 8) 10.3 +/- 3.8 and 848.8 +/- 360.5, respectively. Mean C(max) and AUC (0-infinity) in the mice were: 100 mg/kg lipoic acid: 30.9 +/- 2.9 and 998 +/- 245; 50 mg/kg lipoic acid: 7.6 +/- 1.4 and 223 +/- 20; 20 mg/kg lipoic acid: 2.7 +/- 0.7 and 119 +/- 33. We conclude that patients taking 1200 mg of lipoic acid from two of the three oral formulations achieved serum C(max) and AUC levels comparable to that observed in mice receiving 50 mg/kg subcutaneous dose of lipoic acid, which is a highly therapeutic dose in experimental autoimmune encephalomyelitis. A dose of 1200 mg oral lipoic acid can achieve therapeutic serum levels in patients with multiple sclerosis.