Cell surface bound and soluble adhesion molecules in CSF and blood in multiple sclerosis: correlation with MRI-measures of subclinical disease severity and activity

Soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1) and Natalizumab Serum Concentration as Potential Biomarkers for Pharmacodynamics and Treatment Response of Patients with Multiple Sclerosis Receiving Natalizumab

BACKGROUND

Natalizumab (NTZ) is an established treatment for highly active, relapsing-remitting multiple sclerosis. In the context of rare progressive multifocal leukoencephalopathy and extended interval dosing as a treatment option, biomarkers for treatment monitoring are required. Natalizumab serum concentration (NTZ SC) and soluble vascular cell adhesion molecule 1 (sVCAM-1) concentration were shown to change on treatment with NTZ. We aimed to investigate whether NTZ SC and sVCAM-1 could be suitable pharmacodynamic markers and whether they could predict disease activity on NTZ, improving the concept of personalized multiple sclerosis treatment.

METHODS

In a retrospective study at the Medical University of Innsbruck, Austria, we identified patients treated with NTZ and chose samples longitudinally collected during routine follow-ups for the measurement of NTZ SC and sVCAM-1 by an enzyme-linked immunosorbent assay. We correlated these with clinical and demographic variables and clinical outcomes. Furthermore, we analyzed the stability of NTZ SC and sVCAM-1 during treatment.

RESULTS

One hundred and thirty-seven patients were included. We found a strong negative correlation between NTZ SC and sVCAM-1. Both showed significant associations with body mass index, infusion interval, sample age, and anti-drug-antibodies. Natalizumab serum concentration was reduced in extended interval dosing, but not sVCAM-1. Only sVCAM-1 showed a weak association with relapses during treatment, while there was no association with disease progression. Both NTZ SC and sVCAM-1 showed a wide inter-individual distribution while levels in single patients were stable on treatment.

CONCLUSIONS

Soluble vascular cell adhesion molecule 1 is a suitable pharmacodynamic marker during treatment with NTZ, which is significantly reduced already after the first dose, remains stable in individual patients even on extended interval dosing, and strongly correlates with NTZ SC. Because of the high inter-individual range, absolute levels of sVCAM-1 and NTZ SC are difficult to introduce as treatment monitoring biomarkers in order to predict disease activity in single patients.

Cladribine Alters Immune Cell Surface Molecules for Adhesion and Costimulation: Further Insights to the Mode of Action in Multiple Sclerosis

Cladribine (CLAD) is a deoxyadenosine analogue prodrug which is given in multiple sclerosis (MS) as two short oral treatment courses 12 months apart. Reconstitution of adaptive immune function following selective immune cell depletion is the presumed mode of action. In this exploratory study, we investigated the impact of CLAD tablets on immune cell surface molecules for adhesion (CAMs) and costimulation (CoSs) in people with MS (pwMS). We studied 18 pwMS who started treatment with CLAD and 10 healthy controls (HCs). Peripheral blood mononuclear cells were collected at baseline and every 3 months throughout a 24-month period. We analysed ICAM-1, LFA-1, CD28, HLADR, CD154, CD44, VLA-4 (CD49d/CD29), PSGL-1 and PD-1 with regard to their expression on B and T cells (T helper (Th) and cytotoxic T cells (cT)) and surface density (mean fluorescence intensity, MFI) by flow cytometry. The targeted analysis of CAM and CoS on the surface of immune cells in pwMS revealed a higher percentage of ICAM-1 (B cells, Th, cT), LFA-1 (B cells, cT), HLADR (B cells, cT), CD28 (cT) and CD154 (Th). In pwMS, we found lower frequencies of Th and cT cells expressing PSGL-1 and B cells for the inhibitory signal PD-1, whereas the surface expression of LFA-1 on cT and of HLADR on B cells was denser. Twenty-four months after the first CLAD cycle, the frequencies of B cells expressing CD44, CD29 and CD49d were lower compared with the baseline, together with decreased densities of ICAM-1, CD44 and HLADR. The rate of CD154 expressing Th cells dropped at 12 months. For cT, no changes were seen for frequency or density. Immune reconstitution by oral CLAD was associated with modification of the pro-migratory and -inflammatory surface patterns of CAMs and CoSs in immune cell subsets. This observation pertains primarily to B cells, which are key cells underlying MS pathogenesis.

Neuroinflammation and comorbidity of pain and depression

Comorbid depression and chronic pain are highly prevalent in individuals suffering from physical illness. Here, we critically examine the possibility that inflammation is the common mediator of this comorbidity, and we explore the implications of this hypothesis. Inflammation signals the brain to induce sickness responses that include increased pain and negative affect. This is a typical and adaptive response to acute inflammation. However, chronic inflammation induces a transition from these typical sickness behaviors into depression and chronic pain. Several mechanisms can account for the high comorbidity of pain and depression that stem from the precipitating inflammation in physically ill patients. These mechanisms include direct effects of cytokines on the neuronal environment or indirect effects via downregulation of G protein-coupled receptor kinase 2, activation of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase that generates neurotropic kynurenine metabolites, increased brain extracellular glutamate, and the switch of GABAergic neurotransmission from inhibition to excitation. Despite the existence of many neuroimmune candidate mechanisms for the co-occurrence of depression and chronic pain, little work has been devoted so far to critically assess their mediating role in these comorbid symptoms. Understanding neuroimmune mechanisms that underlie depression and pain comorbidity may yield effective pharmaceutical targets that can treat both conditions simultaneously beyond traditional antidepressants and analgesics.

Circadian rhythmicity of inflammatory serum parameters: a neglected issue in the search of biomarkers in multiple sclerosis

Inflammatory serum parameters are intensely investigated in the search of biomarkers for disease activity and treatment response in multiple sclerosis (MS). A reason for contradictory results might be the timing of blood collection for analyzing serum concentrations of inflammatory parameters which are subject to diurnal changes. We included 34 untreated patients with relapsing-remitting MS and 34 age- and sex-matched healthy controls. 12 MS patients showed acute disease activity in corresponding MRI scans. Blood samples were obtained at 7.00, 11.00 am, 2.30, 6.00 and 9.30 pm within 1 day. We determined serum levels of cortisol and inflammatory markers including soluble tumor necrosis factor-beta (sTNF-β), soluble TNF-Receptor-1 (sTNF-R1) and -2 (sTNF-2), soluble vascular adhesion molecule-1 (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1) by ELISA. We observed significantly higher serum levels of sTNF-R1 (p < 0.001) and sTNF-R2 (p < 0.001) in the morning and a significant decline of sICAM-1 (p < 0.005) and sVCAM-1 (p < 0.001) in the afternoon in both, MS patients and healthy controls. Comparison of diurnal serum levels between MS patients with active versus with non-active disease revealed significantly higher serum levels of sVCAM-1 (p < 0.05) around noon and in the early afternoon in MS patients with active disease. A significant decline of sICAM-1 (p < 0.05) in the afternoon was seen in MS patients with active and non-active disease. Our data indicate that increased awareness of potential diurnal serum concentration changes of biomarkers can eliminate one major cause of biased data as they occur in most of the investigated immunological parameters.

Impact of cladribine on soluble adhesion molecules in multiple sclerosis

BACKGROUND

Soluble forms of vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1) and E-Selectin play a role in the regulation of blood-brain barrier damage and represent markers of the clinical course of multiple sclerosis (MS) and magnetic resonance imaging activity. We determined sICAM, sVCAM and sE-Selectin concentrations in the cerebrospinal fluid (CSF) and serum of patients with remitting-relapsing multiple sclerosis before and after cladribine treatment as well as in a control group.

METHODS

We examined 17 patients diagnosed according to McDonald's criteria. Thirteen healthy age-matched subjects served as controls. The ELISA method was used to measure sICAM-1, sVCAM-1 and sE-Selectin.

RESULTS

The concentration of sICAM and sE-Selectin decreased in sera (difference between patients and controls was statistically significant, in the former P < 0.04, in the latter P < 0.0003) but not in the CSF of MS patients after cladribine treatment.

CONCLUSIONS

The reduction in sICAM and sE-Selectin concentrations after cladribine treatment indicates an immuno-suppressive effect of the drug. The changes in levels of sICAM and sE-Selectin after cladribine treatment reflect disease activity and indicate a reduction in the inflammatory reaction.

Adhesion molecules are promising candidates to establish surrogate markers for natalizumab treatment

BACKGROUND

Natalizumab is the first monoclonal antibody therapy approved for multiple sclerosis (MS). Its therapeutic mechanism is the blockade of the α4-integrin subunit of the adhesion molecule (AM) very late activation antigen-4 (VLA-4), which leads to an inhibition of immune cell extravasation into the central nervous system (CNS).

METHODS

We investigated changes in the expression levels of unblocked α4-integrin and further AM (intercellular adhesion molecule-1, -2, -3 (cICAM-1, -2, -3), leukocyte function associated antigen-1 (LFA-1)) on peripheral blood mononuclear cells (PBMC) determined by flow cytometry from 25 patients with MS before the first natalizumab infusion and before the fourth infusion. In 15 MS patients AM expression was evaluated every 3 months over 1 year.

RESULTS

We found a significant decrease (p < 0.0001) of unblocked α4-integrin cell surface expression on all investigated PBMC subsets (T cells -61.7%, B cells -69.1%, monocytes/macrophages -46.4%) in the blood of MS patients after 3 months of natalizumab treatment. Moreover, a continuous decrease (p < 0.05) of unblocked α4-integrin expression levels was seen after 3, 6, 9, and 12 months. As a secondary effect, expression levels of the other investigated AM were differentially affected.

CONCLUSIONS

Results show a sustained decrease of unblocked α4-integrin expression not only in all patients but also in all investigated PBMC subsets. This probably results in a continuously decreasing transmigration of PBMC into the CNS and may explain the improved clinical efficacy in the second treatment year and also the increasing risk of progressive multifocal leukoencephalopathy during long-term natalizumab therapy. We conclude that AM expression profiles are promising candidates for the development of a biomarker system to determine both natalizumab treatment response and patients at risk for opportunistic CNS infections.

Natalizumab treatment reduces endothelial activity in MS patients

Vascular cell adhesion molecule-1 a ligand for leukocyte very late activating antigen-4 is a key player in leukocyte extravasation in MS lesions. Natalizumab a monoclonal antibody against VLA-4 blocks this interaction. VCAM-1 and its soluble form are up-regulated during endothelial activation in MS. We investigated the effect of Natalizumab on sVCAM-1 and VLA-4 on circulating leukocytes in MS patients. Natalizumab reduced levels of sVCAM-1 compared to controls (256 vs. 597 ng/mL). This effect was sustained and only reversed in patients with neutralizing antibodies against Natalizumab. Correspondingly Natalizumab diminished VLA-4 on leukocyte subsets. Our findings indicate that Natalizumab reduces transmigration not only by blocking VLA-4 but also by down-regulating VCAM-1.

A cannabinoid agonist interferes with the progression of a chronic model of multiple sclerosis by downregulating adhesion molecules

Adhesion molecules are critical players in the regulation of transmigration of blood leukocytes across the blood-brain barrier in multiple sclerosis (MS). Cannabinoids (CBs) are potential therapeutic agents in the treatment of MS, but the mechanisms involved are only partially known. Using a viral model of MS we observed that the cannabinoid agonist WIN55,212-2 administered at the time of virus infection suppresses intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in brain endothelium, together with a reduction in perivascular CD4+ T lymphocytes infiltrates and microglial responses. WIN55,212-2 also interferes with later progression of the disease by reducing symptomatology and neuroinflammation. In vitro data from brain endothelial cell cultures, provide the first evidence of a role of peroxisome proliferator-activated receptors gamma (PPARgamma) in WIN55,212-2-induced downregulation of VCAM-1. This study highlights that inhibition of brain adhesion molecules by WIN55,212-2 might underline its therapeutic effects in MS models by targeting PPAR-gamma receptors.

Time course of VCAM-1 and ICAM-1 in CSF in patients with basal ganglia haemorrhage

OBJECTIVES

In a pilot study we found a correlation of the clinical outcome with adhesion molecule (AM) concentrations in ventricular cerebrospinal fluid (CSF) but not in serum in patients with intracerebral haemorrhage. We now determined the time course of AM concentration in CSF and serum after basal ganglia haemorrhage (BGH) in order to further uncover pathogenetic mechanisms.

MATERIALS AND METHODS

We included 11 patients with acute BGH and ventricular tamponade in which an extraventricular drainage had been applied to treat ventricular ballonade. Paired CSF and serum samples were obtained within 8 h after onset of BGH, as well as on the consecutive days 2, 4, 6, and 8, respectively. The concentrations of soluble ICAM-1 (sICAM-1) and VCAM-1 (sVCAM-1) in CSF and serum were measured by enzyme-linked immunosorbent assay. Moreover, we determined blood volume and perifocal oedema by a semi-automated planimetry technique from initial cranial computed tomography scans.

RESULTS

sICAM-1 and sVCAM-1 levels in CSF were highest within the first hours after onset of BGH, then decreased significantly (P < 0.005 and <0.05, respectively) on day 2 and slightly increased thereafter. Furthermore, BGH volume was significantly correlated with the concentrations of sICAM-1 (r = 0.63, P < 0.05) and sVCAM-1 (r = 0.66, P < 0.05) in ventricular CSF but not in serum.

CONCLUSIONS

Our results might indicate that the local inflammatory reaction is pronounced early after onset of BGH and appears to be restricted to the central nervous system. Moreover, AM concentrations measured early after BGH onset correlated stronger with radiological and clinical data than follow-up measurements.

Cell surface adhesion molecules and cytokine profiles in primary progressive multiple sclerosis

OBJECTIVE

We evaluated the utility of adhesion molecule (AM) and cytokine/chemokine expressions in blood and cerebrospinal fluid (CSF) as markers of disease activity in primary progressive multiple sclerosis (PPMS).

METHODS

The expressions of AMs and the levels of 17 cytokines in patients with PPMS (n = 25) were compared with those in secondary progressive MS (SPMS) (n = 18) and controls (n =11) and correlated with the volumes of focal and atrophic changes on MRI.

RESULTS

The expressions of very late activation antigen 4 (VLA-4), lymphocyte function-associated antigen 1 (LFA-1) and intercellular adhesion molecule 1 (ICAM-1) in blood and CSF were higher in PPMS than in controls. Comparison between PPMS and SPMS showed higher levels of ICAM-1 in blood and CSF in PPMS, while the level of the vascular adhesion molecule (VCAM-1) was higher only in blood. There was no difference in the levels of cytokines in serum or CSF between PPMS and SPMS or controls, but evidence suggesting intrathecal synthesis of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) was found in PPMS. The expressions of CSF VLA-4 in PPMS correlated with the total volume of cerebral lesions and the number of diffuse brain lesions in MRI, while the amount of LFA-1 in CSF correlated with the number of spinal T2 lesions. The level of serum MIP-1beta correlated with the T2 lesion load and EDSS score in PPMS.

CONCLUSIONS

The upregulated expressions of AMs in blood and CSF and evidence for intrathecal synthesis of MCP-1 and IL-8 in PPMS indicate the importance of inflammatory changes in the pathogenesis of PPMS.

The impact of interferon-beta treatment on the blood-brain barrier

Changes in the blood-brain barrier (BBB) are crucial to the pathogenesis of multiple sclerosis (MS). There are currently few established treatments for MS, and interferon-beta (IFN-beta) therapy is one of the most promising - proposed to act as an immunomodulator of the cytokine network reducing inflammatory damage. However, there is increasing evidence that direct effects on the BBB could also be relevant. This review surveys the evidence that IFN-beta stabilizes the BBB, and that this process itself might be the key target. Understanding IFN-beta-derived changes at the BBB will not only provide new insights in the pathogenesis of MS but will also be helpful to develop new, more-specific drugs for MS treatment.

Interferon-beta-1a induces increases in vascular cell adhesion molecule: implications for its mode of action in multiple sclerosis

We investigated soluble vascular cell adhesion molecule-1 (sVCAM) levels and MRI lesions over 24 weeks in 15 Relapsing Remitting MS (RRMS) patients randomized prospectively to receive once-weekly (qw) IFN-beta-1a 30 mug intramuscularly (IM) (Group I, 8 patients) or three-times-weekly (tiw) IFN-beta-1a 44 mug subcutaneously (SC) (Group II, 7 patients). Both groups demonstrated a significant increase in sVCAM during treatment when compared to pre-treatment levels. Patients on IFN-beta-1a 44 mug SC tiw had a significant (p<0.0001) mean increase in sVCAM of 321.9 ng/ml which was significantly greater (p<0.0001) than with IFN-beta-1a 30 mug IM qw (68.6 ng/ml). There was a negative correlation between combined unique (CU) MRI lesions and sVCAM levels within the IFN-beta-1a 44 mug SC tiw group (slope=-0.00106, p=0.009). We postulate that the mode of action of IFN-beta therapy in MS may involve the induction of an increase in sVCAM. sVCAM could bind VLA-4 on T-cells and intercept their adhesion to the blood brain barrier (BBB). This mechanism is consistent with the observed clinical effect of IFN-beta in reducing MRI contrast enhancing lesions.

Expression of adhesion molecules on peripheral lymphocytes predicts future lesion development in MS

The expression of adhesion molecules (alpha4beta1-integrin, LFA-1, ICAM-1) on T cells, measured by flow cytometry, was compared in different subtypes of multiple sclerosis (MS) and related to future lesion development as seen as delta T1 and T2 lesion load per year on magnetic resonance imaging (MRI). LFA-1 and alpha4beta1-integrin showed higher expression on CD4 and CD8 T lymphocytes in the secondary progressive compared to the relapsing-remitting (CD4: p<0.01, p=ns, p<0.05; CD8: p<0.001, p<0.001, p<0.001, respectively) and primary progressive MS phase (CD4: p<0.001, p<0.01, p<0.05; CD8: p<0.01, p<0.01, p<0.001, respectively). The adhesion molecule expression of alpha4- (r=0.31; p<0.05) and beta1-integrin (r=0.38; p<0.01) on CD4+ cells and of LFA-1beta on both CD4+ and CD8+ (r=0.28, p<0.05) and r=0.29; p<0.05, respectively) cells was significantly related to increase in T2 lesion load. Our study provides further evidence for the involvement of integrins in lesion development, shown as T2 lesions on MRI in MS.

CD45RA+ ICAM-3+ lymphocytes in interferon-beta1b-treated and -untreated patients with relapsing-remitting multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is believed to be an autoimmune disease of the human central nervous system mediated by autoreactive T cells. Interferon-beta1b (IFN-beta1b) has been shown to be effective in reducing disease activity defined by clinical and magnetic resonance imaging (MRI) criteria in relapsing-remitting MS (RRMS). Yet, the exact mechanisms by which these benefits are achieved remain unknown. CD45RA is a marker for naive T lymphocytes and intercellular adhesion molecule-3 (ICAM-3) is expressed on resting lymphocytes.

MATERIAL AND METHODS

Forty-eight patients with RRMS, 24 of them treated with recombinant IFN-beta1b and 24 untreated, were enrolled in this prospective study over 18 months. We investigated the percentage of CD45RA+ ICAM-3+ cells within the total lymphocyte subset in the peripheral blood serially every 3 months and in CSF once at baseline. Detailed clinical examination including Expanded Disability Status Scale (EDSS) score was performed every 3 months and cranial MRI scans were assessed every 6 months.

RESULTS

We found a temporary increase in the CD45RA+ ICAM-3+ lymphocyte ratio in peripheral blood of both untreated and IFN-beta1b-treated RRMS patients. Moreover, we determined a significant negative correlation (r = -0.5874; P < 0.01) between age as well as the EDSS score (r = -0.3629; P < 0.05) and the percentages of CD45RA+ ICAM-3+ lymphocytes in peripheral blood but a positive correlation between EDSS score and the CD45RA+ ICAM-3+ ratio (r = 0.3913; P < 0.05) in the CSF at baseline.

CONCLUSION

CD45RA+ ICAM-3+ lymphocyte ratio in peripheral blood might indicate immunosenescence in MS. However, from our data it cannot be finally concluded whether it is also influenced by IFN-beta1b treatment.

Gene expression profiling of relevant biomarkers for treatment evaluation in multiple sclerosis

Multiple sclerosis (MS) is thought to correlate with an array of clinically relevant biomarkers produced during inflammatory process. In this study, a novel gene expression profiling technology was developed and characterized to quantitatively measure the expression profiles of 34 genes selected based on their role in inflammation and their susceptibility to regulation by current MS treatment agents, beta-interferon (IFN) and glatiramer acetate (GA). Potential clinical applications of the technology were evaluated by in vitro and ex vivo analyses in peripheral blood mononuclear cells (PBMC) obtained from MS patients and controls. Interferon-inducible genes were universally up-regulated after in vitro treatment with beta-IFN while the expression of other selected genes encoding cytokines and molecules related to T cell trafficking, activation and apoptosis was variably affected. Beta-IFN and GA exhibited distinctive and characteristic regulatory effects on the expression of the selected genes. Similar regulatory properties of beta-IFN and GA were seen by ex vivo analysis of PBMC specimens in a self-paired study by comparing specific changes induced by beta-IFN or GA treatment in the same patients as well as in a group study by measuring specific profiles in treatment groups compared with an untreated group. Furthermore, the technology served as a simple and sensitive assay for detection of beta-IFN neutralizing antibody based on the blocking effect of serum antibodies on the known regulatory properties of beta-IFN on PBMC. The findings provide important information on the immunoregulatory properties of beta-IFN and GA and support potential clinical applications of this technology in detection of neutralizing antibody (NAB) and evaluation of treatment responses in MS patients.

Cytokine producing CD8+ T cells are correlated to MRI features of tissue destruction in MS

Specific T-cell subsets and their ability to produce cytokines have been involved in concepts of multiple sclerosis (MS) pathogenesis. Evidence to link cytokine producing T-cell subsets to magnetic resonance imaging (MRI) features of tissue destruction, however, is limited. Cytokine flow cytometry was performed in 124 patients with different subtypes of MS. In a subgroup of 69 patients, from whom longitudinal MRI was available, the ability of circulating types 1 and 2 helper T cells to produce cytokines was correlated to changes in T1 hypointense and T2 hyperintense lesion load (LL) on brain MRI during 3 years of follow-up. Significant negative correlations were found between baseline CD8(+) T-cell subsets producing IL-2, IL-4 or IL-13 and the change in T1 LL. Subgroup analyses demonstrated that in RRMS, CD8(+) T cells producing IL-2, IL-4 or IL-13, and in PPMS, CD8(+) IL-10(+) T cells correlated negatively with T1 LL. To our knowledge, this study provides the first direct immunophenotypic evidence of cytokine producing CD8(+) T cells being directly related to long-term development of MRI features of demyelination and axonal loss.

Neuropathology of multiple sclerosis-new concepts

Multiple sclerosis is a chronic inflammatory disease of the central nervous system with profound heterogeneity in clinical course, neuroradiological presentation and response to therapy. The pathological analysis of 235 actively demyelinating lesions coming from three centers revealed different structural and immunological features suggesting that different pathogenetic mechanisms are involved in lesion formation. On the basis of the presence or absence of immunoglobulin and complement deposition, myelin protein loss and the patterns of oligodendrocyte degeneration beside a T cell- and macrophage-dominated immune response, four distinct patterns of demyelination have been identified. In this short review, possible paraclinical markers for tissue destruction on the basis of the main features of myelin destruction are discussed. Furthermore, the importance of early axonal damage in multiple sclerosis is highlighted.

Nitric oxide metabolite determinations reveal continuous inflammation in multiple sclerosis

Nitric oxide (NO) is formed as a consequence of induction of the iNOS enzyme during inflammatory disorders. To investigate NO production in multiple sclerosis (MS), we determined the concentrations of its oxidation products (NOx) in the cerebrospinal fluid (CSF) and plasma of 61 MS patients. The patients were divided into three groups on the basis of their clinical disease activity. The total levels of NOx in CSF were significantly increased in all MS groups as compared to healthy controls and tension headache patients. CSF nitrite correlated with clinical disease activity. At exacerbation, the CSF nitrite levels exceed the plasma level. This suggests that clinical disease activity is due to a CNS inflammatory response, which is more intense and qualitatively different from that during clinical stable phases. This study supports NO involvement in the pathogenesis of MS and determination of nitrite levels may be useful a surrogate marker for disease activity.