Brain endothelial cell expression of SPARCL-1 is specific to chronic multiple sclerosis lesions and is regulated by inflammatory mediators in vitro.

AIMS: Cell matrix modulating protein SPARCL-1 is highly expressed by astrocytes during CNS development and following acute CNS damage. Applying NanoLC-MS/MS to CSF of RRMS and SPMS patients, we identified SPARCL-1 as differentially expressed between these two stages of MS, suggesting a potential as CSF biomarker to differentiate RRMS from SPMS and a role in MS pathogenesis. METHODS: This study examines the potential of SPARCL-1 as CSF biomarker discriminating RRMS from SPMS in three independent cohorts (n = 249), analyses its expression pattern in MS lesions (n = 26), and studies its regulation in cultured human brain microvasculature endothelial cells (BEC) after exposure to MS-relevant inflammatory mediators. RESULTS: SPARCL-1 expression in CSF was significantly higher in SPMS compared to RRMS in a Dutch cohort of 76 patients. This finding was not replicated in 2 additional cohorts of MS patients from Sweden (n = 81) and Switzerland (n = 92). In chronic MS lesions, but not active lesions or NAWM, a vessel expression pattern of SPARCL-1 was observed in addition to the expression by astrocytes. EC were found to express SPARCL-1 in chronic MS lesions, and SPARCL-1 expression was regulated by MS-relevant inflammatory mediators in cultured human BEC. CONCLUSIONS: Conflicting results of SPARCL-1's differential expression in CSF of three independent cohorts of RRMS and SPMS patients precludes its use as biomarker for disease progression. The expression of SPARCL-1 by BEC in chronic MS lesions together with its regulation by inflammatory mediators in vitro suggest a role for SPARCL-1 in MS neuropathology, possibly at the brain vascular level.

CSF neurofilament and N-acetylaspartate related brain changes in clinically isolated syndrome.

BACKGROUND: Axonal damage is considered a major cause of disability in multiple sclerosis (MS) and may start early in the disease. Specific biomarkers for this process are of great interest. OBJECTIVE: To study if cerebrospinal fluid (CSF) biomarkers for axonal damage reflect and predict disease progression already in the earliest stages of the disease, that is, in clinically isolated syndrome (CIS). METHODS: We assessed CSF levels of neurofilament heavy (NFH), neurofilament light (NFL) and N-acetylaspartate (NAA) in 67 patients with CIS and 18 controls with neuropsychiatric diseases of non-inflammatory aetiology (NC). Patients with CIS underwent baseline magnetic resonance imaging (MRI) at 3T, and a follow-up MRI after 1 year was obtained in 28 of them. RESULTS: Compared with NC, patients with CIS had higher NFH (p=0.05) and NFL (p<0.001) levels. No significant group differences were found for NAA. Patients' NFH levels correlated with physical disability (r=0.304, p<0.05) and with change in brain volume over 1 year of follow-up (r=-0.518, p<0.01) but not with change in T2 lesion load. CONCLUSION: Our results confirm increased neurofilament levels already in CIS being related to the level of physical disability. The association of NFH levels with brain volume but not lesion volume changes supports the association of these markers with axonal damage.

Identification of biomarkers for diagnosis and progression of MS by MALDI-TOF mass spectrometry.

INTRODUCTION: Body fluid biomarkers for clinical subtyping and monitoring of disease progression are of considerable interest in multiple sclerosis (MS). Proteomics tools are optimal for the unbiased simultaneous detection of large series of peptides and proteins. OBJECTIVES: To identify novel candidate biomarkers discriminating patients with MS from patients with other neurological diseases (OND), and for subtyping of relapsing-remitting (RR), secondary progressive (SP) and primary progressive (PP) MS patients using a high-throughput MALDI-TOF-based mass spectrometry method. METHODS: Paired cerebrospinal fluid (CSF) and serum samples of 41 RRMS, 30 SPMS, 13 PPMS patients and 25 patients with OND were analysed. RESULTS: Out of a total of 100 detected peptides in CSF and 200 peptides in serum, 11 peptides were differentially regulated in serum and two in CSF between patients with MS and the OND control group. Eleven peptides were differentially regulated in both serum and CSF between relapse-onset MS and PPMS patients. Lastly, four peptides were differentially regulated in serum and two in CSF between RRMS and SPMS patients. Specific peaks regulated in MS were tentatively identified as fragments of secretogranin III and complement C3. The peak intensity of the CSF peptide ion with m/z value 8607.7 correlated to atrophy (r = -0.27, p < 0.005), black hole volumes (r = 0.31, p < 0.008) and total lesion load (r = 0.34, p < 0.003). A serum peptide with m/z value of 872.4 elevated in SPMS correlated to Expanded Disability Status Scale (r = 0.341, p < 0.005) and atrophy (r = -0.286, p < 0.028). CONCLUSIONS: Using high-throughput body fluid profiling by MALDI-TOF mass spectrometry, small proteins and peptides were detected as promising candidate biomarkers for diagnosis and disease progression of MS.

Combination of CSF N-acetylaspartate and neurofilaments in multiple sclerosis.

OBJECTIVE: Axonal degeneration is the likely cause of disease progression in multiple sclerosis (MS). Our previous results indicated that neuron-specific N-acetylaspartate (NAA) is a candidate CSF biomarker for disease progression in MS. The aim of this study was to explore the potential of NAA as an early biomarker of axonal damage in MS. Next, we wanted to know the additional value of measurement of NAA compared to other candidate markers for axonal damage, such as neurofilament subunits and tau protein. METHODS: Levels of NAA, neurofilament light, neurofilament heavy, and tau were determined in CSF of patients with clinically isolated syndrome (CIS, n = 38), relapsing-remitting MS (RRMS, n = 42), secondary progressive MS (SPMS, n = 28), and primary progressive MS (PPMS, n = 6); patients without neurologic disease (ND, n = 28); noninflammatory neurologic controls (n = 18); and inflammatory neurologic controls (n = 39). RESULTS: CSF NAA levels were decreased in patients with SPMS compared to ND controls, patients with CIS, and patients with RRMS. CSF NAA levels in patients with CIS and RRMS were similar to those in ND subjects. All axonal damage proteins showed specific patterns of changes and relations with disease activity measures. The neurofilament light chain levels were already increased in patients with CIS, especially in patients who converted to MS. The neurofilament heavy chain levels were highest in the patients with SPMS. Tau levels were similar in MS and ND. CONCLUSIONS: CSF N-acetylaspartate (NAA) levels were not different from patients without neurologic disease in early stages of multiple sclerosis, though decreased as the disease progressed. Combining CSF NAA and neurofilament levels yields information on different phases of axonal pathology.