Chronic Progressive Stage Research Articles

Neuro-Behçet's disease: an update of clinical diagnosis, biomarkers and immunopathogenesis.

Neuro-Behçet's disease (NBD) is a more severe but rare symptom of Behçet's disease (BD), which is mainly divided into parenchymal NBD (p-NBD) involving brain stem, spinal cord, and cerebral cortex. Non-p-NBD manifests as intracranial aneurysm, cerebral venous thrombosis, peripheral nervous system injuries, and mixed parenchymal and non-parenchymal disease. P-NBD is pathologically characterized by perivasculitis presenting with cerebrospinal fluid (CSF) pleocytosis, elevated total protein, and central nervous system (CNS) infiltration of macrophages and neutrophils, which are subdivided into acute and chronic progressive stages according to relapsing-remitting courses and responses to steroids. The diagnosis of NBD depends heavily on clinical features and MRI findings. The lack of laboratory biomarkers has hindered standard diagnostics. CSF IL-6 is the most investigated dimension of NBD and correlates with NBD activity, therapeutic responses, and prognosis. Further investigations have focused on inflammatory biomarkers that reflect the activation of innate and adaptive immune responses. Higher levels of CSF MIF and IAP indicated the activation of macrophages in the CNS; increased IL-17, IL-10, T-bet/GATA-3, and ROR-γt /Foxp3 ratios, marking the disrupted scale of the Th1/Th2 and Th17/Treg axis; and elevated BAFF and IgA/IgM intrathecal synthesis, suggesting that B cells play a dominant role in NBD. CNS destruction and degeneration as a consequence of neuroinflammatory cascades were confirmed by elevated CSF levels of NFL, β2MG, and MBP. Autoantibodies, including anti-STIP-1, anti-Mtch1, anti-B-Crystallin and anti-m-Hsp65, provide substantial evidence for autoimmune essence and underlying microbiological infections in NBD immunopathogenesis. We summarized opinions on the clinical diagnosis, biomarkers, and pathological findings of NBD.

A novel PSMB8 isoform associated with multiple sclerosis lesions induces P-body formation.

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). Current therapies primarily target the inflammatory component of the disease and are highly effective in early stages of MS while limited therapies have an effect in the more chronic progressive stages of MS where resident glia have a larger role. MS lesions tend to be inflammatory even after the initial peripheral immune cell invasion has subsided and this inflammation is known to cause alternative splicing events. We used qPCR of normal-appearing white matter and white matter lesions from postmortem MS tissue, in vitro studies, and immunostaining in MS tissue to investigate the alternative splicing of one gene known to be important during recovery in an animal model of MS, PSMB8. We found a novel, intron-retained isoform which has not been annotated, upregulated specifically in MS patient white matter lesions. We found that this novel isoform activates the nonsense-mediated decay pathway in primary human astrocytes, the most populous glial cell in the CNS, and is then degraded. Overexpression of this isoform in astrocytes leads to an increased number of processing bodies in vitro, the primary site of mRNA decay. Finally, we demonstrated that MS white matter lesions have a higher burden of processing bodies compared to normal-appearing white matter, predominantly in GFAP-positive astrocytes. The increase in alternative splicing of the PSMB8 gene, the stress that this alternative splicing causes, and the observation that processing bodies are increased in white matter lesions suggests that the lesion microenvironment may lead to increased alternative splicing of many genes. This alternative splicing may blunt the protective or reparative responses of resident glia in and around white matter lesions in MS patients.

P38γ MAPK delays myelination and remyelination and is abundant in multiple sclerosis lesions.

Multiple sclerosis is a chronic inflammatory disease in which disability results from the disruption of myelin and axons. During the initial stages of the disease, injured myelin is replaced by mature myelinating oligodendrocytes that differentiate from oligodendrocyte precursor cells. However, myelin repair fails in secondary and chronic progressive stages of the disease and with ageing, as the environment becomes progressively more hostile. This may be attributable to inhibitory molecules in the multiple sclerosis environment including activation of the p38MAPK family of kinases. We explored oligodendrocyte precursor cell differentiation and myelin repair using animals with conditional ablation of p38MAPKγ from oligodendrocyte precursors. We found that p38γMAPK ablation accelerated oligodendrocyte precursor cell differentiation and myelination. This resulted in an increase in both the total number of oligodendrocytes and the migration of progenitors ex vivo and faster remyelination in the cuprizone model of demyelination/remyelination. Consistent with its role as an inhibitor of myelination, p38γMAPK was significantly downregulated as oligodendrocyte precursor cells matured into oligodendrocytes. Notably, p38γMAPK was enriched in multiple sclerosis lesions from patients. Oligodendrocyte progenitors expressed high levels of p38γMAPK in areas of failed remyelination but did not express detectable levels of p38γMAPK in areas where remyelination was apparent. Our data suggest that p38γ could be targeted to improve myelin repair in multiple sclerosis.

Selective PDE4 subtype inhibition provides new opportunities to intervene in neuroinflammatory versus myelin damaging hallmarks of multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) characterized by focal inflammatory lesions and prominent demyelination. Even though the currently available therapies are effective in treating the initial stages of disease, they are unable to halt or reverse disease progression into the chronic progressive stage. Thus far, no repair-inducing treatments are available for progressive MS patients. Hence, there is an urgent need for the development of new therapeutic strategies either targeting the destructive immunological demyelination or boosting endogenous repair mechanisms. Using in vitro, ex vivo, and in vivo models, we demonstrate that selective inhibition of phosphodiesterase 4 (PDE4), a family of enzymes that hydrolyzes and inactivates cyclic adenosine monophosphate (cAMP), reduces inflammation and promotes myelin repair. More specifically, we segregated the myelination-promoting and anti-inflammatory effects into a PDE4D- and PDE4B-dependent process respectively. We show that inhibition of PDE4D boosts oligodendrocyte progenitor cells (OPC) differentiation and enhances (re)myelination of both murine OPCs and human iPSC-derived OPCs. In addition, PDE4D inhibition promotes in vivo remyelination in the cuprizone model, which is accompanied by improved spatial memory and reduced visual evoked potential latency times. We further identified that PDE4B-specific inhibition exerts anti-inflammatory effects since it lowers in vitro monocytic nitric oxide (NO) production and improves in vivo neurological scores during the early phase of experimental autoimmune encephalomyelitis (EAE). In contrast to the pan PDE4 inhibitor roflumilast, the therapeutic dose of both the PDE4B-specific inhibitor A33 and the PDE4D-specific inhibitor Gebr32a did not trigger emesis-like side effects in rodents. Finally, we report distinct PDE4D isoform expression patterns in human area postrema neurons and human oligodendroglia lineage cells. Using the CRISPR-Cas9 system, we confirmed that pde4d1/2 and pde4d6 are the key targets to induce OPC differentiation. Collectively, these data demonstrate that gene specific PDE4 inhibitors have potential as novel therapeutic agents for targeting the distinct disease processes of MS.

A dual effect of ursolic acid to the treatment of multiple sclerosis through both immunomodulation and direct remyelination

Current multiple sclerosis (MS) medications are mainly immunomodulatory, having little or no effect on neuroregeneration of damaged central nervous system (CNS) tissue; they are thus primarily effective at the acute stage of disease, but much less so at the chronic stage. An MS therapy that has both immunomodulatory and neuroregenerative effects would be highly beneficial. Using multiple in vivo and in vitro strategies, in the present study we demonstrate that ursolic acid (UA), an antiinflammatory natural triterpenoid, also directly promotes oligodendrocyte maturation and CNS myelin repair. Oral treatment with UA significantly decreased disease severity and CNS inflammation and demyelination in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Importantly, remyelination and neural repair in the CNS were observed even after UA treatment was started on day 60 post immunization when EAE mice had full-blown demyelination and axonal damage. UA treatment also enhanced remyelination in a cuprizone-induced demyelination model in vivo and brain organotypic slice cultures ex vivo and promoted oligodendrocyte maturation in vitro, indicating a direct myelinating capacity. Mechanistically, UA induced promyelinating neurotrophic factor CNTF in astrocytes by peroxisome proliferator-activated receptor γ(PPARγ)/CREB signaling, as well as by up-regulation of myelin-related gene expression during oligodendrocyte maturation via PPARγ activation. Together, our findings demonstrate that UA has significant potential as an oral antiinflammatory and neural repair agent for MS, especially at the chronic-progressive stage.

A bidirectional association between the gut microbiota and CNS disease in a biphasic murine model of multiple sclerosis

ABSTRACTThe gut microbiome plays an important role in the development of inflammatory disease as shown using experimental models of central nervous system (CNS) demyelination. Gut microbes influence the response of regulatory immune cell populations in the gut-associated lymphoid tissue (GALT), which drive protection in acute and chronic experimental autoimmune encephalomyelitis (EAE). Recent observations suggest that communication between the host and the gut microbiome is bidirectional. We hypothesized that the gut microbiota differs between the acute inflammatory and chronic progressive stages of a murine model of secondary-progressive multiple sclerosis (SP-MS). This non-obese diabetic (NOD) model of EAE develops a biphasic pattern of disease that more closely resembles the human condition when transitioning from relapsing-remitting (RR)-MS to SP-MS. We compared the gut microbiome of NOD mice with either mild or severe disease to that of non-immunized control mice. We found that the mice which developed a severe secondary form of EAE harbored a dysbiotic gut microbiome when compared with the healthy control mice. Furthermore, we evaluated whether treatment with a cocktail of broad-spectrum antibiotics would modify the outcome of the progressive stage of EAE in the NOD model. Our results indicated reduced mortality and clinical disease severity in mice treated with antibiotics compared with untreated mice. Our findings support the hypothesis that there are reciprocal effects between experimental CNS inflammatory demyelination and modification of the microbiome providing a foundation for the establishment of early therapeutic interventions targeting the gut microbiome that could potentially limit disease progression.

Exploring the differences in intestinal dysbiosis induced by CNS inflammatory demyelination and diabetes in non-obese diabetic mice

Abstract Intestinal dysbiosis is being evaluated as an influencing factor in human diseases. Our laboratory works on the general hypothesis that the association is bidirectional and that disease induction affects the composition of the microbiota. Non-obese diabetic (NOD) mice develop spontaneous diabetes unless active experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis, is induced. It was proposed that the complete Freund’s adjuvant used for active induction of EAE protect against diabetes. Interestingly, although oral antibiotics treatment reduces EAE severity in SJL and C57BL/6 mice, others showed that the same treatment exacerbates diabetes in adult NOD mice. We questioned whether two different diseases affecting one animal strain, the NOD mice, affected the microbiota composition differently. We hypothesized that the gut microbiota differs between the acute inflammatory and chronic progressive stages that characterize the NOD EAE model. Further, we proposed differences in the microbiota/disease axis in EAE and diabetes. We observed significant changes in the microbiota of NOD mice that developed a severe secondary form of EAE when compared with healthy control mice. The genera Coprococcus, Ruminococcus, and Akkermansia were found elevated in EAE mice while undetermined members of the families Lactobacillaceae and Christensenellaceae were significantly reduced. Furthermore, we compared the EAE and diabetes microbiome and evaluated the effects of transplantation stool samples obtained from EAE, diabetes and control mice on diabetes progression. Our findings support the hypothesis that there are reciprocal effects between disease induction and the modification of the microbiome.

Placental Stromal Cell Therapy for Experimental Autoimmune Encephalomyelitis: The Role of Route of Cell Delivery.

Multiple sclerosis (MS) is an immune‐mediated disease of the central nervous system (CNS) with no effective treatment available for the chronic‐progressive stage. Cell therapy is a promising therapeutic approach for attenuating the immune‐mediated CNS process. Isolated and expanded human placental stromal cells (hPSCs) possess potent immunomodulatory and trophic properties, making them a good candidate for MS therapy. We examined the potential of hPSC therapy in preventing the onset or attenuating the course of established disease in a murine MS model of myelin oligodendrocyte glycoprotein‐induced experimental autoimmune encephalomyelitis. We examined the feasibility of hPSC systemic delivery by intramuscular (i.m.) implantation rather than the commonly used intravenous injection, which is dose‐limiting and carries the risk of pulmonary obstruction. Our findings showed significant attenuation of the disease only when hPSCs were injected directly to the central nervous system. Intramuscular implanted hPSCs survived at the site of injection for at least 2 months and elicited extensive local immune responses. Intramuscular hPSC implantation before disease onset caused a delay in the appearance of clinical signs and reduced the severity of a relapse induced by repeated challenge with the autoantigen. Intramuscular implantation after disease onset did not affect its course. Thus, pathological analysis of CNS tissue did not show inhibition of neuroinflammation in i.m. hPSC‐implanted mice. Moreover, no apparent effect was seen on the proliferative response of peripheral lymph node cells in these animals. We conclude that to maximize their therapeutic potential in MS, hPSCs should be delivered directly to the affected CNS. Stem Cells Translational Medicine 2017;6:1286–1294

Editorial Comments: Is multiple sclerosis a neurodegenerative or inflammatory disease?

The etiology of multiple sclerosis (MS) and its pathogenesis are unclear in spite of being the topic of much research for many years. Neuropathological examinations provide undisputable evidence of inflammatory processes in acute demyelinating lesions in MS. This by itself is not surprising, since even if these inflammatory processes are secondary to the initial lesion, they may still have unfavorable consequences. In fact, the beneficial effects of high-dose steroid administration in speeding up the recovery from acute MS relapses seem to support this view. The assumption that inflammation has a central role in the disease, rather than an epiphenomenon, has persisted for decades. This assumption that inflammation processes underlie the neurodegenerative process in MS was the basis for chronic therapy with steroids, which has been popular in the past. However, a more critical examination showed this to be an unrewarding treatment. Inflammation is a term used to describe many processes, sometime complementing and at other time opposing each other, some beneficial and others not. Therefore, a systematic study regarding the role of inflammation in MS should be made in a more focused way. The positive effects of b-interferons (which are anti-inflammatory) support a damaging role of inflammation in acute relapses. However, by the same token, their inefficacy during the secondary progenies phase argues against an inflammatory role in the chronic stage. The neurodegenerative component of MS may or may not be a consequence of inflammation. Neither corticosteroids nor specific anti-inflammatory agents like interferons are effective in the chronic progressive stage of MS. Whether other focused anti-inflammatory process modulation could be beneficial remains to be seen. However, the development of such drugs depends on a more refined definition of the inflammatory process components and discovery of specific targeted interventions. For the time being, the jury is still out: Is MS primarily an inflammatory disorder, where the neurodegeneration is a consequence, or is it primarily a neurodegenerative disorder, in which inflammatory responses are secondary, occurring at the beginning but later die out.

Brain Viscoelasticity Alteration in Chronic-Progressive Multiple Sclerosis

IntroductionViscoelastic properties indicate structural alterations in biological tissues at multiple scales with high sensitivity. Magnetic Resonance Elastography (MRE) is a novel technique that directly visualizes and quantitatively measures biomechanical tissue properties in vivo. MRE recently revealed that early relapsing-remitting multiple sclerosis (MS) is associated with a global decrease of the cerebral mechanical integrity. This study addresses MRE and MR volumetry in chronic-progressive disease courses of MS.MethodsWe determined viscoelastic parameters of the brain parenchyma in 23 MS patients with primary or secondary chronic progressive disease course in comparison to 38 age- and gender-matched healthy individuals by multifrequency MRE, and correlated the results with clinical data, T2 lesion load and brain volume. Two viscoelastic parameters, the shear elasticity μ and the powerlaw exponent α, were deduced according to the springpot model and compared to literature values of relapsing-remitting MS.ResultsIn chronic-progressive MS patients, μ and α were reduced by 20.5% and 6.1%, respectively, compared to healthy controls. MR volumetry yielded a weaker correlation: Total brain volume loss in MS patients was in the range of 7.5% and 1.7% considering the brain parenchymal fraction. All findings were significant (P<0.001).ConclusionsChronic-progressive MS disease courses show a pronounced reduction of the cerebral shear elasticity compared to early relapsing-remitting disease. The powerlaw exponent α decreased only in the chronic-progressive stage of MS, suggesting an alteration in the geometry of the cerebral mechanical network due to chronic neuroinflammation.

Characterization of brain lesions in a mouse model of progressive multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by damage to the neuronal myelin sheath, which results in different levels of muscle paralysis that can lead to neuronal death. In most MS mouse models, the neurologic damage mostly affects the spinal cord with limited damage to the brain, which cannot be monitored by magnetic resonance imaging (MRI) as used for humans. We show that immunization of non-obese diabetic (NOD) mice with myelin oligodendrocyte glycoprotein peptide 35–55 leads to the development of relapsing–remitting stages, evident from days 20 to 70, which then develops into a chronic progressive stage. This cycle is similar to MS stages found in humans. Brain MRI gadolinium-enhanced T1-weighted image analysis showed an increased blood–brain barrier permeability in brain gray and white matter specific to the corpus callosum, fimbria, and internal capsule as found in humans. MRI fractional anisotropy analysis showed demyelination and axonal damage in identical regions. Immunohistologic analysis supported the MRI data. No evidence of brain lesions was found in a common model of MS using C57BL/6 mice. We suggest that an increase in astrocyte toxicity in experimental autoimmune encephalomyelitis-induced NOD mice may be linked to brain lesion development. We suggest using NOD mice as a suitable model for studying MS using MRI methods toward future diagnostic and drug development.

Roles of B Lymphocytes in Multiple Sclerosis: Diversifying beyond the Antibody Response

B lymphocytes have several potentially relevant roles in the pathogenesis of multiple sclerosis and have become increasingly important targets for therapy. Beyond the production of antimyelin antibodies, these roles may include antigen presentation, cytokine production and the establishment of ectopic lymphoid tissue in the CNS compartment, which could provide a local inflammatory stimulus driving the chronic progressive stages of the disease. B cells may also have important roles as regulatory cells, especially through the production of anti-inflammatory cytokines such as IL-10. In the study by Matushita et al., the impact of B-cell depletion by an anti-CD20 monoclonal antibody was studied in the animal model of experimental autoimmune encephalomyelitis (EAE). Timing of drug administration had a dramatic impact on outcome: depletion preceding EAE induction resulted in an increase in disease severity, in comparison with suppression when the drug was administered after the appearance of clinical signs. This phenomenon was not related to a decrease in antibody levels; instead, it was explained by a preferential effect of anti-CD20 on a regulatory B-cell population whose function was crucial in initial stages of the disease. In summary, these results further expand our knowledge of the importance of B cells in EAE and, potentially, multiple sclerosis, and highlight the complex and often paradoxical results of immunotherapy in autoimmune disorders.

Animal models of pulmonary fibrosis: how far from effective reality?

idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease, associated with high mortality rates and unresponsive to currently available treatments. Animal models are critical to identify and validate new therapeutic drug targets, a concept that is nicely highlighted by the review

Aspects cliniques, physiopathologiques, et thérapeutiques de la sclérose en plaques

Multiple sclerosis (MS) is characterized by multiple demyelinating lesions disseminated in the central nervous system. The clinical course of MS involves acute attacks leading to permanent disability and a chronic progressive stage occurring at the beginning of the disease or after a relapsing-remitting phase. Investigations that provide supportive evidence for the diagnosis of MS are magnetic resonance imaging and cerebrospinal fluid examination. Recent pathological studies showed evidence of early axonal pathology, remyelination in some cases, and diffuse pathology. Genetic and immunological studies suggest that MS is an auto-immune disease, partially genetically determined but the role of an environmental factor, possibly infectious is possible. Cumulative evidence of the efficacy of interferon beta and other disease-modifying drug therapy has completely modified the therapeutic approach of MS.

Axonal damage in acute multiple sclerosis lesions.

One of the histological hallmarks of early multiple sclerosis lesions is primary demyelination, with myelin destruction and relative sparing of axons. On the other hand, it is widely accepted that axonal loss occurs in, and is responsible for, the permanent disability characterizing the later chronic progressive stage of the disease. In this study, we have used an antibody against amyloid precursor protein, known to be a sensitive marker of axonal damage in a number of other contexts, in immunocytochemical experiments on paraffin embedded multiple sclerosis lesions of varying ages in order to see at which stage of the disease axonal damage, in addition to demyelination, occurs and may thus contribute to the development of disability in patients. The results show the expression of amyloid precursor protein in damaged axons within acute multiple sclerosis lesions, and in the active borders of less acute lesions. This observation may have implications for the design and timing of therapeutic intervention, one of the most important aims of which must be the reduction of permanent disability.

Defective post-thymic tolerance mechanisms during the chronic progressive stage of multiple sclerosis.

We have recently isolated a panel of T-cell clones from chronic progressive multiple sclerosis (MS) patients that are capable of functioning as antigen-presenting cells and of expressing the costimulatory molecules B7-1 and B7-2. In this report we show that these T-cell clones are resistant to inhibitory regulation, including the induction of anergy and sensitivity to tumor growth factor-beta (TGF-beta)-induced growth inhibition. The resistance to anergy induction was associated with expression of B7 costimulatory molecules. These data suggest that lack of responsiveness to peripheral inhibitory signals may account for the entry of autoimmune diseases into a chronic progressive phase.

Low dose oral methotrexate treatment of multiple sclerosis: a pilot study.

An 18-month double-blind treatment of multiple sclerosis with low dose oral methotrexate showed it to be well tolerated and suggested effectiveness in exacerbating-remitting MS but not in the exacerbating progressive and chronic progressive stages.

Susceptibility for multiple sclerosis is determined, in part, by inheritance of a 175-kb region of the TcR Vβ chain locus and HLA class II genes

Genetic makeup thought to affect susceptibility to multiple sclerosis (MS) and current evidence suggests that multiple genes may be involved. We have mapped a potential susceptibility gene or genes in the germ-line T cell receptor (TcR) Vβ region of multiple sclerosis (MS) patients. Six restriction fragment length polymorphisms (RFLPs) spanning approximately 600 kb of the TcR Vβ region were used to define TcR haplotypes in 197 Caucasian controls and 83 Caucasian MS patients in the chronic progressive stage of the disease. The distribution of TcR subhaplotype frequencies was significantly different only in the approx. 175-kb region between RFLPs defined by Vβ8.1 and Vβ11. Stratification of the MS patients into HLA-DR2 + ( n = 51) and HLA-DR2 − ( n = 32) populations demonstrated that the subhaplotype frequencies differed from the control population significantly only in the HLA-DR2 + (corrected P = 0.00007) and not in the HLA-DR2 − (corrected P = 0.46) population. Subhaplotypes which are rare in the normal population are overrepresented in the HLA-DR2 + MS patient population and confer a relative risk of 4.06. These results indicate the existence of an MS susceptibility gene within the TcR Vβ region, and provide new evidence for gene complementation between a HLA class II gene and TcR Vβ gene(s) in conferring susceptibility to MS.

Chronic progressive multiple sclerosis: serial magnetic resonance brain imaging over six months.

Eight patients in the chronic progressive stage of multiple sclerosis were studied prospectively with magnetic resonance imaging of the head and neurological examination every 2 weeks for 6 months. There were no clinical relapses and disability ratings did not change between the start and completion of the study. Despite the clinical inactivity, a total of 86 active events (new, reappearing, or enlarging lesions) were identified by magnetic resonance imaging over the 6 months, with 50 (51%) of 98 follow-up scans showing evidence of one or more active lesions. New and changing lesions were indistinguishable in appearance, distribution, and temporal pattern from those previously seen in patients who had relapsing and remitting multiple sclerosis. However, as noted previously, the patients in the chronic progressive stage had many more confluent lesions than did the group in relapse. These results strongly suggest that the frequently observed clinical evolution of multiple sclerosis into a chronic progressive course is not accompanied by a fundamental change in the disease process. In fact the chronic progressive stage seems associated with more active changes demonstrated by scans than does relapsing and remitting multiple sclerosis. This study also confirms our previous experience that serial magnetic resonance imaging is much more sensitive than clinical examination in detecting disease activity in multiple sclerosis.