A low-fat diet improves fatigue in multiple sclerosis: Results from a randomized controlled trial.

BACKGROUND: Fatigue can be a disabling multiple sclerosis (MS) symptom with no effective treatment options. OBJECTIVE: Determine whether a low-fat diet improves fatigue in people with MS (PwMS). METHODS: We conducted a 16-week randomized controlled trial (RCT) and allocated PwMS to a low-fat diet (active, total daily fat calories not exceeding 20%) or wait-list (control) group. Subjects underwent 2 weeks of baseline diet data collection (24-hour diet recalls (24HDRs)), followed by randomization. The active group received 2 weeks of nutrition counseling and underwent a 12-week low-fat diet intervention. One set of three 24HDRs at baseline and week 16 were collected. We administered a food frequency questionnaire (FFQ) and Modified Fatigue Impact Scale (MFIS) every 4 weeks. The control group continued their pre-study diet and received diet training during the study completion. RESULTS: We recruited 39 PwMS (20-active; 19-control). The active group decreased their daily caloric intake by 11% (95% confidence interval (CI): -18.5%, -3.0%) and the mean MFIS by 4.0 (95% CI: -12.0, 4.0) compared to the control (intent-to-treat). Sensitivity analysis strengthened the association with a mean MFIS difference of -13.9 (95% CI: -20.7, -7.2). CONCLUSIONS: We demonstrated a significant reduction in fatigue with a low-fat dietary intervention in PwMS.

Rituximab for treatment of refractory multiple sclerosis relapses during pregnancy.

Case Summary: While multiple sclerosis (MS) disease activity declines during pregnancy, there are situations where MS relapses in pregnant women do occur. Mild relapses may be managed with close observation, but severe refractory relapses may require more aggressive management. We describe two cases of rituximab used for severe, refractory multiple sclerosis relapses during pregnancy. Rituximab did not appear to complicate either pregnancy and there were no further relapses for either women. Rituximab should not be overlooked in rare refractory cases, such as the rebound relapses sometimes seen following the discontinuation of lymphocyte-sequestering disease-modifying therapies.

MIF and D-DT are potential disease severity modifiers in male MS subjects.

Little is known about mechanisms that drive the development of progressive multiple sclerosis (MS), although inflammatory factors, such as macrophage migration inhibitory factor (MIF), its homolog D-dopachrome tautomerase (D-DT), and their common receptor CD74 may contribute to disease worsening. Our findings demonstrate elevated MIF and D-DT levels in males with progressive disease compared with relapsing-remitting males (RRMS) and female MS subjects, with increased levels of CD74 in females vs. males with high MS disease severity. Furthermore, increased MIF and D-DT levels in males with progressive disease were significantly correlated with the presence of two high-expression promoter polymorphisms located in the MIF gene, a -794CATT5-8 microsatellite repeat and a -173 G/C SNP. Conversely, mice lacking MIF or D-DT developed less-severe signs of experimental autoimmune encephalomyelitis, a murine model of MS, thus implicating both homologs as copathogenic contributors. These findings indicate that genetically controlled high MIF expression (and D-DT) promotes MS progression in males, suggesting that these two factors are sex-specific disease modifiers and raising the possibility that aggressive anti-MIF treatment of clinically isolated syndrome or RRMS males with a high-expresser genotype might slow or prevent the onset of progressive MS. Additionally, selective targeting of MIF:CD74 signaling might provide an effective, trackable therapeutic approach for MS subjects of both sexes.

Dietary Interventions and Multiple Sclerosis.

Multiple Sclerosis (MS) is a chronic, disabling neurologic disease that has its onset in young adulthood. While the knowledge about underlying pathogenesis of MS has improved significantly over the last few decades, the exact cause still eludes us. Despite the availability of several United States Food and Drug Administration-approved disease-modifying therapies (DMT) for MS in the last two decades, the disease remains disabling for many. DMT use is limited by its partial effectiveness, significant side effects in many cases, and high cost that leads people with MS (PwMS) to look for alternative management options. Dietary intervention as a possible mode to help MS seems very appealing to PwMS; however, scientific data supporting this notion remains sparse. New information on the role of various non-MS health factors, especially vascular disease risk factors such as hypertension, hyperlipidemia, salt intake, and obesity, that may play a role in MS pathogenesis appears very intriguing as it may partly explain the heterogeneity seen in MS activity and disability. This review will highlight the emerging information on various dietary approaches that may affect MS and their possible underlying mechanism.

Correction to: Dietary Interventions and Multiple Sclerosis.

The original version of this article contains an error in the second sentence of the second paragraph of the Paleolithic Diet section.

Hypothalamic Dysfunction and Multiple Sclerosis: Implications for Fatigue and Weight Dysregulation.

Signs and symptoms of multiple sclerosis are usually attributed to demyelinating lesions in the spinal cord or cerebral cortex. The hypothalamus is a region that is often overlooked yet controls many important homeostatic functions, including those that are perturbed in multiple sclerosis. In this review we discuss how hypothalamic dysfunction may contribute to signs and symptoms in people with multiple sclerosis. While dysfunction of the hypothalamic-pituitary-adrenal axis is common in multiple sclerosis, the effects and mechanisms of this dysfunction are not well understood. We discuss three hypothalamic mechanisms of fatigue in multiple sclerosis: (1) general hypothalamic-pituitary-adrenal axis hyperactivity, (2) disordered orexin neurotransmission, (3) abnormal cortisol secretion. We then review potential mechanisms of weight dysregulation caused by hypothalamic dysfunction. Lastly, we propose future studies and therapeutics to better understand and treat hypothalamic dysfunction in multiple sclerosis. Hypothalamic dysfunction appears to be common in multiple sclerosis, yet current studies are underpowered and contradictory. Future studies should contain larger sample sizes and standardize hormone and neuropeptide measurements.

Clinical and radiographic features of a cohort of adult and pediatric subjects in the Pacific Northwest with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a newly described clinical entity comprised of isolated or recurrent attacks of optic neuritis, transverse myelitis, acute disseminated encephalomyelitis (ADEM), encephalitis, or seronegative NMOSD. Prior studies report that 30-80 % of children and adults with MOGAD go on to have relapses though there are no reliable predictors. The objectives of this study were to (1) describe the demographic, clinical, and radiographic patterns of MOGAD at our center and (2) identify possible predictors of relapsing disease. METHODS: Single-center retrospective cohort study of pediatric and adult subjects with MOGAD evaluated at least once at our center between January 1, 2017 and September 30, 2022. Eligible subjects had a history of positive MOG-IgG and consistent clinical syndrome comprised of an initial attack of optic neuritis (ON), transverse myelitis (TM), ADEM, cerebral cortical encephalitis, seronegative neuromyelitis optica (simultaneous ON and TM), isolated brainstem or cerebellar syndrome, or other (not fitting into another group). Relapsing subjects or those remaining monophasic at 12 months were included in the analyses of predictors of relapsing disease. Covariates included age, sex, race/ethnicity, and index event phenotype. Unadjusted and adjusted risk ratios were calculated for pediatric and adult subjects. RESULTS: We describe the demographic, clinical, and radiographic characteristics of 58 subjects with MOGAD. Covariates from 48 subjects were analyzed for predictors of relapsing disease. In adults, Hispanics and non-White non-Hispanics were at increased risk of relapsing disease compared to non-Hispanic Whites [Adjusted RR 1.52 (95 % CI: 1.01, 2.30)]. There were no significant associations in the pediatric group. CONCLUSION: This study is the first to describe a cohort of MOGAD in the Pacific Northwest. Our findings highlight racial and ethnic differences in risk of relapsing MOGAD in adults. Further studies on racial and ethnic differences in MOGAD are needed to confirm these findings.

Vascular disease risk factors in multiple sclerosis: Effect on metabolism and brain volumes.

BACKGROUND: Vascular disease risk factors (VDRF) such as hypertension, hyperlipidemia, obesity, diabetes and heart disease likely play a role in disease progression in people with multiple sclerosis (PwMS) (Marrie, Rudick et al. 2010). Studies exploring the mechanistic connection between vascular disease and MS disease progression are scant. We hypothesized that phosphate energy metabolism impairment in PwMS with VDRFs (VDRF+) will be greater compared to PwMS without VDRFs (VDRF-) and is related to increased brain atrophy in VDRF+. To test this hypothesis, we planned to study the differences in the high energy phosphate (HEP) metabolites in cerebral gray matter as assessed by 31P magnetic resonance spectroscopic imaging (MRSI) and MRI brain volumetric in the VDRF+ and VDRF- PwMS at four different timepoints over a 3 yearlong period using a 7T MR system. We present here the results from the cross-sectional evaluation of HEP metabolites and brain volumes. We also evaluated the differences in clinical impairment, blood metabolic biomarkers and quality of life in VDRF+ and VDRF- PwMS in this cohort. METHODS: Group differences in high energy phosphate metabolites were assessed from a volume of interest in the occipital region using linear mixed models. Brain parenchymal and white matter lesion volumes were determined from MR anatomic images. We present here the cross-sectional analysis of the baseline data collected as part of a longitudinal 3 yearlong study where we obtained baseline and subsequent 6-monthly clinical and laboratory data and annual 7T MRI volumetric and 31P MR spectroscopic imaging (MRSI) data on 52 PwMS with and without VDRF. Key clinical and laboratory outcomes included: body mass index (BMI), waist and thigh circumferences and disability [Expanded Disability Status Scale (EDSS)], safety (complete blood count with differential, complete metabolic), lipid panel including total cholesterol and HbA1C. We analyzed clinical and laboratory data for the group differences using student's t or χ2 test. We investigated relationship between phosphate metabolites and VDRF using mixed effect linear regression. RESULTS: Complete MRI data were available for 29 VDRF+, age 56.3 (6.8) years [mean (SD)] (83% female), and 23 VDRF-, age 52.5 (7.5) years (57% female) individuals with MS. The mean value of normalized adenosine triphosphate (ATP) (calculated as the ratio of ATP to total phosphate signal in a voxel) was decreased by 4.5% (p < .05) in VDRF+ compared to VDRF- MS group. White matter lesion (WML) volume fraction in VDRF+ individuals {0.007 (0.007)} was more than doubled compared to VDRF- participants {0.003 (0.006), p= .02}. CONCLUSIONS: We found significantly lower brain ATP and higher inorganic phosphate (Pi) in those PwMS with VDRFs compared to those without. ATP depletion may reflect mitochondrial dysfunction. Ongoing longitudinal data analysis from this study, not presented here, will evaluate the relationship of phosphate metabolites, brain atrophy and disease progression in PwMS with and without vascular disease.

New disease-modifying therapies and new challenges for MS.

The availability of the second-generation therapies for relapsing multiple sclerosis (MS), natalizumab and fingolimod, provides new treatment options for MS but also presents new challenges. Both natalizumab and fingolimod appear to be more effective than the interferon beta products and glatiramer acetate, but both have more safety problems than do the first-generation therapies. Treatment with natalizumab is associated with a significant risk of patients developing progressive multifocal leukoencephalopathy (PML), which the JC virus causes. We now are able to risk stratify MS patients into high- and low-risk groups for developing PML on the basis of the presence or absence of antibodies to the JC virus, history of prior use of immunosuppressants, and duration of therapy with natalizumab. Fingolimod appears to be associated with a risk of asystole and sudden death. It may also increase the risk of serious herpes infections and paradoxical activation of MS. More information is needed about these serious side effects from fingolimod to allow us to use it safely in patients.

C-L Case Conference: A 33-Year-Old Bhutanese Woman With Postpartum Hallucinations.

We describe the case of a 33-year-old pre-eclamptic Bhutanese woman who presented with postpartum hallucinations. We discuss our concern for postpartum psychosis versus a culturally appropriate phenomenon, with her diagnostic picture complicated by the use of interpreters and the intersection of culture and medicine. Top experts in the consultation-liaison (CL) field provide guidance for this clinical scenario based on their experience and a review of the available literature. This case highlights both the impact of language barriers and the challenges of interpreting psychiatric symptoms within a cultural context. Key teaching points include differential diagnoses for postpartum hallucinations, the importance of interpreting patient presentations within their unique cultural contexts and identities, and the impact of language interpretation on patient care. Specifically, we offer guidance on differentiating postpartum psychosis from a culturally appropriate phenomenon.

Curriculum Innovations: Virtual Didactics as a Tool for Harmonizing Education About Rare Topics in Neuroimmunology.

Introduction and Problem Statement: Neuroimmunology is a rapidly evolving subspecialty. At this time, fellowship training is not standardized. Discrepancies exist in fellowship programs across the United States, including in faculty expertise in rarer neuroimmunologic conditions. Many graduating fellows feel uncomfortable managing the full spectrum of diseases within neuroimmunology. Objectives: To evaluate the feasibility and efficacy of a series of live, virtual, interinstitutional seminars educating neuroimmunology fellows on topics that may be infrequently encountered by trainees. Methods and Curriculum Description: A steering committee of 6 neuroimmunology and multiple sclerosis fellowship program directors selected 18 topics felt to be high yield but representing unique areas of expertise. A live, interactive seminar series was organized. Recognized experts on each topic led seminars using a teleconferencing platform over the 2020-2021 academic year. Recordings were subsequently made available for asynchronous learning. Trainees were surveyed before and after the seminar series and comfort levels with each topic were recorded. Results and Assessment Data: An average of 41 trainees participated in each live seminar and an additional average of 17 trainees viewed each seminar on demand. Trainee comfort levels with each topic increased after the seminar series was completed. An average of 72% of trainees self-identified as at least "comfortable" with each topic after the series compared with 26% beforehand (p < 0.0001). Discussion and Lessons Learned: A year-long series of live, interactive, interinstitutional seminars focusing on unique topics within a single subspecialty represents an effective way to increase trainee comfort levels with such topics.

A cross-sectional survey of cannabis use by people with MS in Oregon and Southwest Washington.

BACKGROUND: Evidence supports that cannabinoids reduce self-reported spasticity and neuropathic pain in people with MS (PwMS), and legal access to cannabis for medical and recreational use continues to rise. However, there are limited data regarding patterns of cannabis use and perceived benefits of cannabis among PwMS in the US. This study describes the prevalence of cannabis use, routes of administration, perceived benefit of cannabis for MS, and characteristics associated with cannabis use and perception of benefit among a population of PwMS living in two states where cannabis is legal for both medical and recreational use. METHODS: A survey about treatments used by PwMS, focusing on complementary and alternative medicine (CAM), was sent to PwMS living in Oregon and Southwest Washington. This survey included questions about current and past cannabis use, route of cannabis administration, and perceived benefits, as well as personal demographics. RESULTS: Of the 1188 returned surveys, 1000 had at least 75% complete survey responses and also completed the questions about current and past cannabis use. Thirty percent (n=303) of respondents reported currently using cannabis, 21% (n=210) used in the past but not currently, and 49% (n=487) had never used cannabis. Among current users, rates of use by smoking, vaping, topicals, tinctures and oils, or edibles were similar (35-46%), and most (59%) reported using multiple routes of administration. Most (64-78%, varying by route) current and past users reported cannabis being very or somewhat beneficial for their MS. The odds of current cannabis use were higher in PwMS who: 1) were younger (OR 2.24 [95% CI 1.39-3.61] for those age 18-40 compared with age >60]; 2) had lower household income (OR 3.94 [95% CI 2.55-6.09] with annual income <$25k compared with those with >$100k); 3) had secondary progressive MS (OR 1.77 [95% CI 1.07-2.92]); and 4) had more than minimal MS disability (OR 2.05 [95% CI 1.03-4.10] for those using a walker compared to those with none/minimal disability). The odds of perceiving cannabis as beneficial for MS were higher in: 1) younger individuals (OR 5.61 [95% CI 2.62-11.98] for those age 18-40 compared with age >60); 2) those with lower household income (OR 3.35 [95% CI 1.65-6.80] with annual income <$25k compared with those with >$100k), 3) those not currently using disease modifying therapies (OR 2.32 [95% CI 1.30-4.13]), and 4) those with the greatest disability (OR 17.96; [95% CI 2.00-161.22]). CONCLUSION: In this survey, 30% of PwMS reported currently using cannabis for their MS, mostly by multiple routes of administration, and most of these people report this being helpful for their MS. People who were younger, had lower household income, had progressive disease, and had more than minimal disability were more likely to use cannabis and report it was beneficial for their MS. People who were not using disease modifying therapies were also more likely to report benefit from cannabis use.

Consensus Curriculum for Fellowship Training in Multiple Sclerosis and Neuroimmunology.

Management of multiple sclerosis and neuroimmunologic disorders has become increasingly complex because of the expanding number of recognized neuroimmune disorders, increased number of therapeutic options, and multidisciplinary care management needs of people with multiple sclerosis and neuroimmunologic disorders. More subspecialists are needed to optimize care of these patients, and many fellowship programs have been created or expanded to increase the subspecialty workforce. Consequently, defining the scope and standardizing fellowship training is essential to ensure that trainees receive high-quality training. A workgroup was created to develop a consensus fellowship curriculum to serve as a resource for all current and future training programs. This curriculum may also serve as a basis for future accreditation efforts.

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.

Spinal adhesive arachnoiditis mimicking sarcoid myelitis with nodular dural enhancement: A case report.

Spinal adhesive arachnoiditis (SAA) is a rare, but often devastating, cause of compressive myelopathy. We report a patient with SAA resulting in a longitudinally extensive T2-hyperintense spinal cord lesion with initial nodular pial and dural enhancement mimicking neurosarcoidosis. Neurologists should be aware of this entity, especially in patients who have pertinent risk factors, such as prior meningitis, spinal cord trauma, or surgery.

Cross-sectional survey of complementary and alternative medicine used in Oregon and Southwest Washington to treat multiple sclerosis: A 17-Year update.

BACKGROUND: In 2001, we conducted a survey on use of complementary and alternative medicine (CAM) in people with multiple sclerosis (pwMS) in Oregon and Southwest Washington to treat their disease. OBJECTIVES, METHODS: In 2018, we administered a revised survey in the same region to describe updated patterns of CAM use in pwMS and to compare changes in use, perceived benefit, and patterns of communication between participants and providers regarding CAM over the past 17 years. RESULTS: 81% of respondents in 2018 (n = 1014) used a CAM supplement (vitamins, minerals, herbs), 39% used mind-body therapies (mindfulness, massage), 41% used specific diet, and 81% used exercise to treat their multiple sclerosis. Since 2001, use of supplements, exercise, and mind-body therapies have increased (65% to 81%, 67 to 81%, and 14% to 39%). Participants were also nine times more likely to speak to their neurologists about CAM use (6.7% to 55.4%). In 2018, factors associated with CAM use included female sex, progressive disease, and longer time since multiple sclerosis diagnosis. CONCLUSION: These findings highlight the high and increasing prevalence of CAM use in pwMS and factors associated with CAM use, and underscore the importance of research to investigate safety and efficacy of these therapies.

Oral lipoic acid as a treatment for acute optic neuritis: a blinded, placebo controlled randomized trial.

BACKGROUND: Lipoic acid, an antioxidant, has beneficial effects in experimental acute optic neuritis and autoimmune encephalomyelitis. Optical coherence tomography can detect retinal nerve fiber layer thinning, representing axonal degeneration, approximately 3-6 months after acute optic neuritis. OBJECTIVE: To determine whether lipoic acid is neuroprotective in acute optic neuritis. METHODS: A single-center, double-blind, randomized, placebo controlled, 24-week trial. Intervention included 6 weeks of once daily lipoic acid (1200 mg) or placebo within 14 days of acute optic neuritis diagnosis. The primary outcome was the mean difference in affected eye retinal nerve fiber layer (RNFL) thickness from baseline to 24 weeks. RESULTS: We enrolled 31 subjects (placebo n=16; lipoic acid n=15; average age 38.6 years (standard deviation (SD) 10.3)). Affected eye mean global RNFL thickness (µm) in the lipoic acid group decreased from 108.47 (SD 26.11) at baseline to 79.31 (SD 19.26) at 24 weeks. The affected eye RNFL in the placebo group decreased from 103.67 (SD 18.04) at baseline to 84.43 (SD 20.94) at 24 weeks. Unaffected eye RNFL thickness did not significantly change in either group over 24 weeks. CONCLUSION: Six weeks of oral lipoic acid supplementation after acute optic neuritis is safe and well tolerated; however, because of insufficient recruitment, we could not conclude that lipoic acid treatment was neuroprotective in acute optic neuritis.

Therapeutic vaccination with a trivalent T-cell receptor (TCR) peptide vaccine restores deficient FoxP3 expression and TCR recognition in subjects with multiple sclerosis.

Therapeutic vaccination using T-cell receptor (TCR) peptides from V genes commonly expressed by potentially pathogenic T cells remains an approach of interest for treatment of multiple sclerosis (MS) and other autoimmune diseases. We developed a trivalent TCR vaccine containing complementarity determining region (CDR) 2 peptides from BV5S2, BV6S5 and BV13S1 emulsified in incomplete Freund's adjuvant that reliably induced high frequencies of TCR-specific T cells. To evaluate induction of regulatory T-cell subtypes, immunological and clinical parameters were followed in 23 treatment-naïve subjects with relapsing-remitting or progressive MS who received 12 monthly injections of the trivalent peptide vaccine over 1 year in an open-label study design. Prior to vaccination, subjects had reduced expression of forkhead box (Fox) P3 message and protein, and reduced recognition of the expressed TCR repertoire by TCR-reactive cells compared with healthy control donors. After three or four injections, most vaccinated MS subjects developed high frequencies of circulating interleukin (IL)-10-secreting T cells specific for the injected TCR peptides and significantly enhanced expression of FoxP3 by regulatory T cells present in both 'native' CD4+ CD25+ and 'inducible' CD4+ CD25- peripheral blood mononuclear cells (PBMC). At the end of the trial, PBMC from vaccinated MS subjects retained or further increased FoxP3 expression levels, exhibited significantly enhanced recognition of the TCR V gene repertoire apparently generated by perturbation of the TCR network, and significantly suppressed neuroantigen but not recall antigen responses. These findings demonstrate that therapeutic vaccination using only three commonly expressed BV gene determinants can induce an expanded immunoregulatory network in vivo that may optimally control complex autoreactive responses that characterize the inflammatory phase of MS.

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 .