The pharmacokinetics and dosing of oral 4-methylumbelliferone for inhibition of hyaluronan synthesis in mice.

Recently, there has been considerable interest in using 4-methylumbelliferone (4-MU) to inhibit hyaluronan (HA) synthesis in mouse models of cancer, autoimmunity and a variety of other inflammatory disorders where HA has been implicated in disease pathogenesis. In order to facilitate future studies in this area, we have examined the dosing, treatment route, treatment duration and metabolism of 4-MU in both C57BL/6 and BALB/c mice. Mice fed chow containing 5% 4-MU, a dose calculated to deliver 250 mg/mouse/day, initially lose substantial weight but typically resume normal weight gain after 1 week. It also takes up to a week to see a reduction in serum HA in these animals, indicating that at least a 1-week loading period on the drug is required for most protocols. At steady state, more than 90% of the drug is present in plasma as the glucuronidated metabolite 4-methylumbelliferyl glucuronide (4-MUG), with the sulphated metabolite, 4-methylumbelliferyl sulphate (4-MUS) comprising most of the remainder. Chow containing 5% but not 0·65% 4-MU was effective at preventing disease in the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis, as well as in the DORmO mouse model of autoimmune diabetes. While oral 4-MU was effective at preventing EAE, daily intraperitoneal injections of 4-MU were not. Factors potentially affecting 4-MU uptake and plasma concentrations in mice include its taste, short half-life and low bioavailability. These studies provide a practical resource for implementing oral 4-MU treatment protocols in mice.

Why are prions and amyloid structures immune suppressive and other intriguing questions facing neuroimmunologists in the future.

The immune system plays a major role in certain diseases of the brain like multiple sclerosis and neuromyelitis optica, while the brain may play a major role in modulating certain immunologic diseases of the periphery like inflammatory bowel disease. The most significant developments in neuroimmunology will involve explorations of the roles for the immune system in neurodegenerative conditions often associated with the presence of amyloid deposits. Here I present my personal perspectives on four of the most intriguing challenges that we face in the future of neuroimmunology: (1) Why are the traditional hallmarks of innate and adaptive inflammation conspicuously absent from brains of individuals with prion disease and amyloid pathology? (2) What is the role of adaptive and innate immunity in progressive forms of multiple sclerosis? (3) Is molecular mimicry an adequate explanation for the initiation of neuroinflammatory disease and for exacerbations in conditions like multiple sclerosis, narcolepsy, and neuromyelitis optica? (4) Do neural pathways regulate inflammatory diseases outside the nervous system?

Serum IL-17F does not predict poor response to IM IFNß-1a in relapsing-remitting MS.

OBJECTIVE: There is a significant unmet need for serum biomarkers in relapsing-remitting multiple sclerosis (RRMS) that are predictive of therapeutic response to disease-modifying therapies. Following a recent Stanford study which reported that pretreatment levels of serum interleukin (IL)-17F could predict poor response to interferon-ß (IFNß) therapy, we sought to validate the finding using samples from a large clinical trial. METHODS: The validation cohort included 54 good responders (GR) and 64 poor responders (PR) selected from 762 subjects with RRMS from the IM IFNß-1a dose comparison study (Avonex study C94-805). Subjects were classified as GR and PR based on the number of relapses, Expanded Disability Status Scale score, and new and enlarging T2 lesions on MRI. Serum samples were assayed for IL-17F using a multiplexed Luminex assay and for IL-17F/F using an ELISA. Replicate aliquots from the Stanford study were also assayed to assure reproducibility of methods. RESULTS: Median pretreatment and post-treatment serum IL-17F levels were not statistically significantly different between GR and PR, and serum IL-7/IL-17F ratios were also not predictive of response status. Replicate aliquots from the Stanford study showed good correlation to their original cohort (r = 0.77). CONCLUSIONS: We were unable to validate the finding that serum IL-17F is a predictor of PR in a large independent cohort of subjects with RRMS. Differences in patient populations and methodology might explain the failure to validate the results from the Stanford study.

Functional rescue of experimental ischemic optic neuropathy with αB-crystallin.

PURPOSE: Anterior ischemic optic neuropathy (AION) is an important cause of acute vision loss in adults, and there is no effective treatment. We studied early changes following experimental AION and tested the benefit of a potential treatment. MATERIALS AND METHODS: We induced experimental AION in adult mice and tested the effects of short-term (daily for 3 days) and long-term (every other day for 3 weeks) αB-crystallin (αBC) treatment using histological and serial intracranial flash visual evoked potential recordings. RESULTS: One day after experimental AION, there was swelling at the optic nerve (ON) head and increased expression of αBC, a small heat shock protein important in ischemia and inflammation. This upregulation coincided with microglial and astrocytic activation. Our hypothesis was that αBC may be part of the endogenous protective mechanism against injury, thus we tested the effects of αBC on experimental AION. Daily intraveneous or intravitreal αBC injections did not improve visual evoked potential amplitude or latency at days 1-2. However, αBC treatment decreased swelling and dampened the microglial and astrocytic activation on day 3. Longer treatment with intravenous αBC led to acceleration of visual evoked potential latency over 3 weeks, without improving amplitude. This latency acceleration did not correlate with increased retinal ganglion cell survival but did correlate with complete rescue of the ON oligodendrocytes, which are important for myelination. CONCLUSIONS: We identified αBC as an early marker following experimental AION. Treatment with αBC enhanced this endogenous, post-ischemic response by decreasing microglial activation and promoting ON oligodendrocyte survival.

Inverse vaccination, the opposite of Jenner's concept, for therapy of autoimmunity.

DNA-based vaccines to induce antigen-specific inhibition of immune responses in human autoimmune diseases represent the inverse of what Jenner intended when he invented vaccination. Jenner's vaccine induced antigen-specific immunity to small pox. DNA vaccines for autoimmunity have been developed in preclinical settings, and now tested in human trials. The first two clinical trials, one in relapsing remitting multiple sclerosis, and the other in type 1 diabetes indicate that specific inhibition of antigen-specific antibody and T-cell responses is attainable in humans. Further development of this approach is ongoing. This new version of immunization termed 'inverse vaccination' when applied to autoimmune diseases, may allow targeted reduction of unwanted antibody and T-cell responses to autoantigens, while leaving the remainder of the immune system intact. The method of specifically reducing a pathological adaptive autoimmune response is termed inverse vaccination.

Tryptophan degradation in autoimmune diseases.

Recent evidence points to tryptophan (Trp) degradation as a potent immunosuppressive mechanism involved in the maintenance of immunological tolerance. Both Trp depletion and downstream Trp catabolites (TCs) appear to synergistically confer protection against excessive inflammation. In this review, we give an overview of the immunosuppressive properties of Trp degradation with special focus on TCs. Constitutive and inducible Trp degradation in different cell types and tissues of human and murine origin is summarized. We address the influence of Trp degradation on different aspects of autoimmune disorders such as multiple sclerosis. Possible therapeutic approaches for autoimmune disorders targeting Trp degradation are presented, and key issues relevant for the development of such therapeutic strategies are discussed.

Suppression of autoimmunity via microbial mimics of altered peptide ligands.

Molecular mimics of self-antigens can behave as altered peptide ligands and serve to ameliorate autoimmune disease. Analysis of experimental autoimmune encephalomyelitis with proteomic autoantibody microarrays reveals that there might exist a wide variety of microbes with features that mimic self-epitopes. Autoimmunity could therefore be modulated via microbial immunity, which may account for relapse and remission of ongoing disease.

Characterizing the mechanisms of progression in multiple sclerosis: evidence and new hypotheses for future directions.

Major advancements have been achieved in our ability to diagnose multiple sclerosis (MS) and to commence treatment intervention with agents that can favorably affect the disease course. Although MS exacerbations and the emergence of disability constitute the more conspicuous aspects of the disease process, evidence has confirmed that most of the disease occurs on a constitutive and occult basis. Disease-modifying therapies appear to be modest in the magnitude of their treatment effects, particularly in the progressive stage of the disease. Therapeutic strategies currently used for MS primarily target the inflammatory cascade. Several potential mechanisms appear to be involved in the progression of MS. Characterizing these mechanisms will result in a better understanding of the various forms of the disorder and how to effectively treat its clinical manifestations. It is our objective within this 2-part series on progression in MS to offer both evidence-based observations and hypothesis-driven expert perspectives on what constitutes the cause of progression in MS. We have chosen areas of inquiry that appear to have been most productive in helping us to better conceptualize the landscape of what MS looks like pathologically, immunologically, neuroscientifically, radiographically, and genetically. We have attempted to advance hypotheses focused on a deeper understanding of what contributes to the progression of this illness and to illustrate new technical capabilities that are catalyzing novel research initiatives targeted at achieving a more complete understanding of progression in MS.

The multifaceted role of transglutaminase in neurodegeneration: review article.

A critical role for transglutaminase [TGase] has been hypothesized in the pathogenesis of the CAG trinucleotide repeat diseases, characterized by proteins with abnormal expansions of a polyglutamine domain. In the last few years the involvement of TGase in neurodegenerative diseases [NDS], including its role in aggregate formation, has been broadened to include Alzheimer's [AD] and Parkinson's Disease [PD]. It is clear that reduction of TGase activity is beneficial for prolonged survival in mouse models of NDS. The pathological progression of these diseases might reflect in part increases of TGase induced aggregates, or changes in other pathways influenced by increases in TGase activity. Neurodegeneration may be influenced by increased TGase activity affecting apoptosis, modulation of GTPase activity and signal transduction. This review will focus on the leading hypotheses in relation to both old and new experimental results.

Risk factors associated with exertional medial tibial pain: a 12 month prospective clinical study.

OBJECTIVE: To investigate in a military setting the potential role of intrinsic biomechanical and anthropometric risk factors for, and the incidence of, exertional medial tibial pain (EMTP). METHODS: A prospective clinical outcome study in a cohort of 122 men and 36 women at the Australian Defence Force Academy. Each cadet underwent measurements of seven intrinsic variables: hip range of motion, leg length discrepancy, lean calf girth, maximum ankle dorsiflexion range, foot type, rear foot alignment, and tibial alignment. Test-retest reliability was undertaken on each variable. A physician recorded any cadet presenting with diagnostic criteria of EMTP. Records were analysed at 12 months for EMTP presentation and for military fitness test results. RESULTS: 23 cadets (12 men, 11 women) met the criteria for EMTP after 12 months, with a cross gender (F/M) odds ratio of 3.1. In men, both internal and external range of hip motion was greater in those with EMTP: left internal (12 degrees, p = 0.000), right internal (8 degrees, p = 0.014), left external (8 degrees, p = 0.042), right external (9 degrees, p = 0.026). Lean calf girth was lower by 4.2% for the right leg (p = 0.040) but by only 2.9% for the left leg (p = 0.141). No intrinsic risk factor was associated with EMTP in women. EMTP was the major cause for non-completion of the run component of the ADFA fitness test in both men and women. CONCLUSIONS: Greater internal and external hip range of motion and lower lean calf girth were associated with EMTP in male military cadets. Women had high rates of injury, although no intrinsic factor was identified. Reasons for this sex difference need to be identified.

The potential therapeutic role of statins in central nervous system autoimmune disorders.

3-hydroxy-3-methyglutaryl coenzyme A (HMG-CoA) reductase inhibitors, 'statins' are widely used oral cholesterol-lowering drugs. Statins competitively inhibit HMG-CoA reductase, the enzyme that catalyzes conversion of HMG-CoA to L-mevalonate, a key intermediate in cholesterol synthesis. Certain metabolites of mevalonate are also involved in posttranslational modification of specific proteins involved in cell proliferation and differentiation. Thus, statins have important biologic effects that may be independent of their cholesterol-reducing properties. Recent studies indicate that statins have antiinflammatory and neuroprotective properties which may be beneficial in the treatment of multiple sclerosis as well as other central nervous system (CNS) neurodegenerative diseases. This article will outline current experimental evidence that may suggest potential clinical benefits for patients with CNS autoimmune disorders. Ultimately, clinical trials will have to determine the safety and efficacy of statins in this patient population.

Osteopontin polymorphisms and disease course in multiple sclerosis.

Osteopontin (OPN), also known as early T-cell activating gene (Eta-1), has been recently shown to be a critical factor in the progression of experimental autoimmune encephalomyelitis, and perhaps multiple sclerosis (MS). Here we investigated whether the 327T/C, 795C/T, 1128A/G or 1284A/C single-nucleotide polymorphisms in the OPN gene were correlated with susceptibility or any of the several clinical end points in a cohort of 821 MS patients. Overall, we observed no evidence of genetic association between the OPN polymorphisms and MS. Although not reaching statistical significance, a modest trend for association with disease course was detected in patients carrying at least one wild-type 1284A allele, suggesting an effect on disease course. Patients with this genotype were less likely to have a mild disease course and were at increased risk for a secondary-progressive clinical type.

N(epsilon)-(gamma-L-glutamyl)-L-lysine (GGEL) is increased in cerebrospinal fluid of patients with Huntington's disease.

Pathological-length polyglutamine (Q(n)) expansions, such as those that occur in the huntingtin protein (htt) in Huntington's disease (HD), are excellent substrates for tissue transglutaminase in vitro, and transglutaminase activity is increased in post-mortem HD brain. However, direct evidence for the participation of tissue transglutaminase (or other transglutaminases) in HD patients in vivo is scarce. We now report that levels of N(epsilon)-(gamma-L-glutamyl)-L-lysine (GGEL)--a 'marker' isodipeptide produced by the transglutaminase reaction--are elevated in the CSF of HD patients (708 +/- 41 pmol/mL, SEM, n = 36) vs. control CSF (228 +/- 36, n = 27); p < 0.0001. These data support the hypothesis that transglutaminase activity is increased in HD brain in vivo.

The influence of the proinflammatory cytokine, osteopontin, on autoimmune demyelinating disease.

Multiple sclerosis is a demyelinating disease, characterized by inflammation in the brain and spinal cord, possibly due to autoimmunity. Large-scale sequencing of cDNA libraries, derived from plaques dissected from brains of patients with multiple sclerosis (MS), indicated an abundance of transcripts for osteopontin (OPN). Microarray analysis of spinal cords from rats paralyzed by experimental autoimmune encephalomyelitis (EAE), a model of MS, also revealed increased OPN transcripts. Osteopontin-deficient mice were resistant to progressive EAE and had frequent remissions, and myelin-reactive T cells in OPN-/- mice produced more interleukin 10 and less interferon-gamma than in OPN+/+ mice. Osteopontin thus appears to regulate T helper cell-1 (TH1)-mediated demyelinating disease, and it may offer a potential target in blocking development of progressive MS.