Frank Vandenabeele

Leukemia inhibitory factor is produced by myelin-reactive T cells from multiple sclerosis patients and protects against tumor necrosis factor-α-induced oligodendrocyte apoptosis

In multiple sclerosis (MS), damage to oligodendrocytes is believed to be caused by an aberrant immune response initiated by autoreactive T cells. Increasing evidence indicates that these T cells are not exclusively detrimental but might also exert protective effects. We report for the first time that myelin‐reactive T‐cell clones from eight MS patients (6/19) and five healthy controls (4/11) produce leukemia inhibitory factor (LIF), a member of the neuropoietic family of neurotrophins. In addition, T‐cell clones specific for tetanus toxoid, CD4+ and CD8+ T cells, and monocytes, but not B cells, secreted LIF. LIF‐producing T lymphocytes and macrophages were also identified immunohistochemically in both active and chronic‐active MS lesions. We further demonstrated dose‐dependent protective effects of LIF on tumor necrosis factor‐α‐induced apoptosis of oligodendrocytes. In conclusion, our data demonstrate that peripheral and CNS‐infiltrating T cells from MS patients produce LIF, a protective factor for oligodendrocytes. This study emphasizes that secretion of LIF may contribute to the neuroprotective effects of autoreactive T cells.

Alpha-smooth muscle actin (α-SMA) and nestin expression in reactive astrocytes in multiple sclerosis lesions : potential regulatory role of transforming growth factor-beta 1 (TGF-β1)

Aims: Rapid and extensive activation of astrocytes occurs subsequent to many forms of central nervous system (CNS) injury. Recent studies have revealed that the expression profile of reactive astrocytes comprises antigens present during astrocyte development. Elevated levels of the injury‐related cytokine transforming growth factor‐beta 1 (TGF‐β1) secreted by microglial cells and invading macrophages have been correlated with the reactive astrocyte phenotype and glial scar formation. Methods: In the present study, the expression profile of alpha‐smooth muscle actin (α‐SMA) and nestin, two cytoskeletal proteins expressed during astrocyte development, was studied in multiple sclerosis (MS) lesions. In addition, α‐SMA and nestin organization and expression were analysed in rat primary astrocyte cultures in response to TGF‐β1. Results: In active lesions and in the hypercellular margin of chronic active MS lesions, immunostaining for α‐SMA revealed a subpopulation of reactive astrocytes, whereas the majority of reactive astrocytes expressed nestin. α‐SMA and nestin expressing reactive astrocytes were in close relationship with TGF‐β1 expressing macrophages or microglia. In addition, TGF‐β1 expression within α‐SMA or nestin expressing astrocytes was also detected. Our in vitro experiments showed that TGF‐β1 regulated the organization and expression of α‐SMA and nestin in astrocytes. Conclusions: Reactive astrocytes in active MS lesions re‐express α‐SMA and nestin. We suggest that the in vivo re‐expression might be under regulation of TGF‐β1. These results further clarify the regulation of astrocyte activity after CNS injury, which is important for the astroglial adaptation to pathological situations.

Multiple sclerosis affects skeletal muscle characteristics.

Background The impact of multiple sclerosis (MS) on skeletal muscle characteristics, such as muscle fiber cross sectional area (CSA), fiber type proportion, muscle strength and whole muscle mass, remains conflicting. Methods In this cross sectional study, body composition and muscle strength of the quadriceps were assessed in 34 MS (EDSS: 2.5±0.19) patients and 18 matched healthy controls (HC). Hereafter a muscle biopsy (m.vastus lateralis) was taken. Results Compared to HC, mean muscle fiber CSA of all fibers, as well as CSA of type I, II and IIa fibers were smaller and muscle strength of the quadriceps was lower in MS patients. Whole body composition was comparable between groups. However, compared to HC, the biopsied leg tended to have a higher fat percentage (pu200a=u200a0.1) and a lower lean mass (pu200a=u200a0.06) in MS patients. Conclusion MS seems to negatively influence skeletal muscle fiber CSA, muscle strength and muscle mass of the lower limbs of mildly affected MS patients. This emphasises the need for rehabilitation programs focusing on muscle preservation of the lower limb. Trial Registration ClinicalTrials.gov NCT01845896

High Intensity Exercise in Multiple Sclerosis: Effects on Muscle Contractile Characteristics and Exercise Capacity, a Randomised Controlled Trial.

Introduction Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis (MS). The impact of high intensity exercise remains unknown. Methods Thirty-four MS patients were randomized into a sedentary control group (SED, n = 11) and 2 exercise groups that performed 12 weeks of a high intensity interval (HITR, n = 12) or high intensity continuous cardiovascular training (HCTR, n = 11), both in combination with resistance training. M.vastus lateralis fiber cross sectional area (CSA) and proportion, knee-flexor/extensor strength, body composition, maximal endurance capacity and self-reported physical activity levels were assessed before and after 12 weeks. Results Compared to SED, 12 weeks of high intensity exercise increased mean fiber CSA (HITR: +21±7%, HCTR: +23±5%). Furthermore, fiber type I CSA increased in HCTR (+29±6%), whereas type II (+23±7%) and IIa (+23±6%,) CSA increased in HITR. Muscle strength improved in HITR and HCTR (between +13±7% and +45±20%) and body fat percentage tended to decrease (HITR: -3.9±2.0% and HCTR: -2.5±1.2%). Furthermore, endurance capacity (Wmax +21±4%, time to exhaustion +24±5%, VO2max +17±5%) and lean tissue mass (+1.4±0.5%) only increased in HITR. Finally self-reported physical activity levels increased 73±19% and 86±27% in HCTR and HITR, respectively. Conclusion High intensity cardiovascular exercise combined with resistance training was safe, well tolerated and improved muscle contractile characteristics and endurance capacity in MS. Trial Registration ClinicalTrials.gov NCT01845896

Characterization of mature rat oligodendrocytes : a proteomic approach

Oligodendrocytes are glial cells responsible for the synthesis and maintenance of myelin in the central nervous system (CNS). Oligodendrocytes are vulnerable to damage occurring in a variety of neurological diseases. Understanding oligodendrocyte biology is crucial for the dissemination of de‐ and remyelination mechanisms. The goal of the present study is the construction of a protein database of mature rat oligodendrocytes. Post‐mitotic oligodendrocytes were isolated from mature Wistar rats and subjected to immunocytochemistry. Proteins were extracted and analyzed by means of two‐dimensional gel electrophoresis and two‐dimensional liquid chromatography, both coupled to mass spectrometry. The combination of the gel‐based and gel‐free approach resulted in confident identification of a total of 200 proteins. A minority of proteins were identified in both proteomic strategies. The identified proteins represent a variety of functional groups, including novel oligodendrocyte proteins. The results of this study emphasize the power of the applied proteomic strategy to study known or to reveal new proteins and to investigate their regulation in oligodendrocytes in different disease models.

High Intensity Aerobic and Resistance Exercise Can Improve Glucose Tolerance in Persons With Multiple Sclerosis: A Randomized Controlled Trial.

Introduction The prevalence of impaired glucose tolerance (IGT) is higher in persons with multiple sclerosis (MS) compared to healthy controls, indicating metabolic deficits that may increase comorbidity. In other populations, IGT can, at least partly, be reversed by intense physical exercise, but this is never investigated before in MS. Aim To investigate the effect of high intensity aerobic and resistance training on glucose tolerance and skeletal muscle GLUT4 content in MS. Methods Thirty-four persons with MS (aged 45 ± 3 years, EDSS 2.5 ± 1.07) were randomized into three groups, including a (1) sedentary control group (SED, n = 11), (2) 12-week high intensity interval plus resistance training group (HITR, n = 12), or (3) 12-week high intensity continuous aerobic training plus resistance training group (HCTR, n = 11). Before and after 12 weeks, glucose tolerance and skeletal muscle GLUT4 content were determined by an oral glucose tolerance test and analysis of a m.vastus lateralis biopsy, respectively. Results There were no significant changes for subjects of SED. From pre- to post-intervention, total area under the glucose curve (tAUC) decreased significantly in both HITR (−6.9 ± 6.2%) and HCTR (−11.0 ± 7.7%) (P < 0.05). Insulin tAUC decreased (−12.3 ± 14.7%) within HCTR and muscle GLUT4 content increased (+6.6 ± 4.5%) in HITR. Conclusion Twelve weeks of high intensity aerobic exercise in combination with resistance training improved glucose tolerance in persons with MS.

Altered signaling for mitochondrial and myofibrillar biogenesis in skeletal muscles of patients with multiple sclerosis

Patients with multiple sclerosis (pwMS) experience muscle weakness and lowered muscle oxidative capacity. To explore the etiology for the development of such muscle phenotype we studied skeletal muscle adenosine monophosphate (AMP)-activated protein kinase phosphorylation (phospho-AMPKα, governing mitochondrial biogenesis) and mammalian target of rapamycin phosphorylation (phospho-mTOR, governing myofibrillar biogenesis) in pwMS. After assessment of body composition, muscle strength, exercise tolerance, and muscle fiber type, muscle phospho-AMPKα and phospho-mTOR were assessed in 14 pwMS and 10 healthy controls (part 1). Next, an endurance exercise bout was executed by 9 pwMS and 7 healthy subjects, with assessment of changes in muscle phospho-AMPKα and phospho-mTOR (part 2). Increased basal muscle phospho-AMPKα and phospho-mTOR were present in MS (P < 0.01) and independently related to MS. Correlations between muscle phospho-AMPKα or phospho-mTOR and whole-body fat mass, peak oxygen uptake, and expanded disability status scale (P < 0.05) were found. After endurance exercise muscle phospho-AMPKα and phospho-mTOR remained increased in pwMS (P < 0.01). Muscle signaling cascades for mitochondrial and myofibrillar biogenesis are altered in MS and related to the impairment and disability level. These findings indicate a link between muscle signaling cascades and the level of disability and impairment, and thus may open a new area for the development of novel therapies for peripheral muscle impairment in MS.

Muscle Carnosine in Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis

BACKGROUNDnMuscle carnosine is related to contractile function (Ca++ handling) and buffering of exercise-induced acidosis. As these muscular functions are altered in Multiple Sclerosis (MS) it is relevant to understand muscle carnosine levels in MS.nnnMETHODSnTibialis anterior muscle carnosine was measured in an animal MS model (EAE, experimental autoimmune encephalomyelitis, n = 40) and controls (CON, n = 40) before and after exercise training (EAEEX, CONEX, 10d, 1u202fh/d, 24u202fm/min treadmill running) or sedentary conditions (EAESED, CONSED). Human m. vastus lateralis carnosine of healthy controls (HC, n = 22) and MS patients (n = 24) was measured.nnnRESULTSnEAE muscle carnosine levels were decreased (p < .0001) by ~ 40% to ~ 64% at 10d and 17d following EAE induction (respectively) regardless of exercise (p = .823). Similarly, human MS muscle carnosine levels were decreased (- 25%, p = .03).nnnCONCLUSIONnMuscle carnosine concentrations in an animal MS model and MS patients are substantially reduced. In EAE exercise therapy does not restore this.

Feasibility, accuracy and safety of a percutaneous fine-needle biopsy technique to obtain qualitative muscle samples of the lumbar multifidus and erector spinae muscle in persons with low back pain

The lumbar muscular system, in particular the lumbar multifidus muscle (LM) and the erector spinae muscle (ES), plays an important role in stabilizing and mobilizing the lumbar spine. Based on the topography, the lumbar paraspinal muscles can be classified into local and global muscles. LM is part of the local system, whereas ES is part of the global system. Therefore, it is interesting to investigate the muscle fibre type composition in both muscles. There is accumulating evidence that nonspecific chronic low back pain is associated with lumbar muscle dysfunction. To further elucidate this lumbar paraspinal muscle dysfunction, it is important to understand the structural characteristics of individual muscle fibres of LM and ES. Muscle fibre type composition can be investigated in muscle tissue samples. So far, muscle samples are taken by using invasive procedures that are not well tolerated. The aim of this article was to evaluate the feasibility, accuracy and safety of a percutaneous fine‐needle biopsy technique to obtain muscle samples from LM and ES in persons with nonspecific chronic low back pain and to evaluate the feasibility of performing immunofluorescence analysis of myosin heavy chain isoform expression to investigate muscle fibre type composition. Preliminary investigations in cadavers were performed to determine the optimal vertebral level and puncture site to obtain muscle samples of LM and ES through a single skin puncture. In 15 persons with nonspecific chronic low back pain, muscle samples of LM and ES were taken under local anaesthesia with the percutaneous fine‐needle biopsy technique, preceded by determination of the puncture site with ultrasonography. Muscle fibre type composition was investigated using immunofluorescence analysis of myosin heavy chain expression. The subjects reported little or no pain and were willing to repeat the procedure. The obtained muscle tissue contained transverse‐sectioned muscle fibres in which muscle fibre contractile characteristics of the paraspinal muscles could be evaluated with immunofluorescence analysis of the myosin heavy chains. We can conclude that percutaneous microbiopsy appears to be feasible and accurate, and safe to use to obtain muscle tissue from the paraspinal muscles. The use of ultrasonography to determine the puncture site is necessary to ensure biopsy of the correct muscles and to ensure the safety of the procedure.