Increased cerebrospinal fluid chitotriosidase index in patients with multiple sclerosis

CHIT1 at diagnosis predicts faster disability progression and reflects early microglial activation in multiple sclerosis

Multiple sclerosis (MS) is characterized by heterogeneity in disease course and prediction of long-term outcome remains a major challenge. Here, we investigate five myeloid markers - CHIT1, CHI3L1, sTREM2, GPNMB and CCL18 - in the cerebrospinal fluid (CSF) at diagnostic lumbar puncture in a longitudinal cohort of 192 MS patients. Through mixed-effects and machine learning models, we show that CHIT1 is a robust predictor for faster disability progression. Integrative analysis of 11 CSF and 26 central nervous system (CNS) parenchyma single-cell/nucleus RNA sequencing samples reveals CHIT1 to be predominantly expressed by microglia located in active MS lesions and enriched for lipid metabolism pathways. Furthermore, we find CHIT1 expression to accompany the transition from a homeostatic towards a more activated, MS-associated cell state in microglia. Neuropathological evaluation in post-mortem tissue from 12 MS patients confirms CHIT1 production by lipid-laden phagocytes in actively demyelinating lesions, already in early disease stages. Altogether, we provide a rationale for CHIT1 as an early biomarker for faster disability progression in MS.

The roles of fungus in CNS autoimmune and neurodegeneration disorders

Fungal infection or proliferation in our body is capable of initiation of strong inflammation and immune responses that result in different consequences, including infection-trigged organ injury and inflammation-related remote organ dysfunction. Fungi associated infectious diseases have been well recognized in the clinic. However, whether fungi play an important role in non-infectious central nervous system disease is still to be elucidated. Recently, a growing amount of evidence point to a non-negligible role of peripheral fungus in triggering unique inflammation, immune response, and exacerbation of a range of non-infectious CNS disorders, including Multiple sclerosis, Neuromyelitis optica, Parkinson's disease, Alzheimer's disease, and Amyotrophic lateral sclerosis et al. In this review, we summarized the recent advances in recognizing patterns and inflammatory signaling of fungi in different subsets of immune cells, with a specific focus on its function in CNS autoimmune and neurodegeneration diseases. In conclusion, the fungus is capable of triggering unique inflammation by multiple mechanisms in the progression of a body of CNS non-infectious diseases, suggesting it serves as a key factor and critical novel target for the development of potential therapeutic strategies.

Evaluation of cerebrospinal fluid biomarkers in pediatric patients with spinal muscular atrophy

BACKGROUND

Spinal muscular atrophy (SMA) is a rare neuromuscular disorder characterised by muscle weakness and muscle atrophy and classified into five known subtypes based on clinical features. The recent development of novel drugs to treat SMA has been encouraging, and nusinersen is the first drug approved to treat SMA.

OBJECTIVE

To explore cerebrospinal fluid (CSF) biomarkers of SMA and investigate their relationship with symptoms and the treatment response in pediatric patients.

METHODS

We analyzed the CSF levels of chitotriosidase 1 (CHIT1) and inflammatory cytokines (tumor necrosis factor [TNF]-α and interferon [INF]-γ) using enzyme-linked immunosorbent assays in pediatric SMA patients treated at Hiroshima University Hospital over 2 years.

RESULTS

This study analyzed pediatric SMA patients. While the CSF inflammatory cytokines (TNF-α and INF-γ) in these SMA children were unchanged, the CHIT1 levels decreased significantly from year 1 to 2 of treatment. We also found a trend toward an inverse correlation between the motor function score (HINE-2 scores) and CHIT1 level from year 1 to 2 of treatment.

CONCLUSIONS

CHIT1 may be a CSF biomarker of the treatment response in pediatric SMA.

Pharmacotherapeutic Potential of Garlic in Age-Related Neurological Disorders

Age-related neurological disorders [ANDs] involve neurodegenerative diseases [NDDs] such as Alzheimer's disease [AD], the most frequent kind of dementia in elderly people, and Parkinson's disease [PD], and also other disorders like epilepsy and migraine. Although ANDs are multifactorial, Aging is a principal risk factor for them. The common and most main pathologic features among ANDs are inflammation, oxidative stress, and misfolded proteins accumulation. Since failing brains caused by ANDs impose a notable burden on public health and their incidence is increasing, a lot of works has been done to overcome them. Garlic, Allium sativum, has been used for different medical purposes globally and more than thousands of publications have reported its health benefits. Garlic and aged garlic extract are considered potent anti-inflammatory and antioxidants agents and can have remarkable neuroprotective effects. This review is aimed to summarize knowledge on the pharmacotherapeutic potential of garlic and its components in ANDs.

Increased chitotriosidase 1 concentration following nusinersen treatment in spinal muscular atrophy

Background

Studies regarding the impact of (neuro)inflammation and inflammatory response following repetitive, intrathecally administered antisense oligonucleotides (ASO) in 5q-associated spinal muscular atrophy (SMA) are sparse. Increased risk of hydrocephalus in untreated SMA patients and a marginal but significant increase of the serum/CSF albumin ratio (Qalb) with rare cases of communicating hydrocephalus during nusinersen treatment were reported, which confirms the unmet need of an inflammatory biomarker in SMA. The aim of this study was to investigate the (neuro)inflammatory marker chitotriosidase 1 (CHIT1) in SMA patients before and following the treatment with the ASO nusinersen.

Methods

In this prospective, multicenter observational study, we studied CSF CHIT1 concentrations in 58 adult and 21 pediatric patients with SMA type 1, 2 or 3 before treatment initiation in comparison to age- and sex-matched controls and investigated its dynamics during nusinersen treatment. Concurrently, motor performance and disease severity were assessed.

Results

CHIT1 concentrations were elevated in treatment-naïve SMA patients as compared to controls, but less pronounced than described for other neurodegenerative diseases such as amyotrophic lateral sclerosis. CHIT1 concentration did not correlate with disease severity and did not distinguish between clinical subtypes. CHIT1 concentration did show a significant increase during nusinersen treatment that was unrelated to the clinical response to nusinersen therapy.

Conclusions

CHIT1 elevation in treatment-naïve SMA patients indicates the involvement of (neuro)inflammation in SMA. The lacking correlation of CHIT1 concentration with disease severity argues against its use as a marker of disease progression. The observed CHIT1 increase during nusinersen treatment may indicate an immune response-like, off-target reaction. Since antisense oligonucleotides are an establishing approach in the treatment of neurodegenerative diseases, this observation needs to be further evaluated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01961-8.

Chitotriosidase, a biomarker of amyotrophic lateral sclerosis, accentuates neurodegeneration in spinal motor neurons through neuroinflammation

Background

Cerebrospinal fluid from amyotrophic lateral sclerosis patients (ALS-CSF) induces neurodegenerative changes in motor neurons and gliosis in sporadic ALS models. Search for identification of toxic factor(s) in CSF revealed an enhancement in the level and enzyme activity of chitotriosidase (CHIT-1). Here, we have investigated its upregulation in a large cohort of samples and more importantly its role in ALS pathogenesis in a rat model.

Methods

CHIT-1 level in CSF samples from ALS (n = 158), non-ALS (n = 12) and normal (n = 48) subjects were measured using ELISA. Enzyme activity was also assessed (ALS, n = 56; non-ALS, n = 10 and normal-CSF, n = 45). Recombinant CHIT-1 was intrathecally injected into Wistar rat neonates. Lumbar spinal cord sections were stained for Iba1, glial fibrillary acidic protein and choline acetyl transferase to identify microglia, astrocytes and motor neurons respectively after 48 h of injection. Levels of tumour necrosis factor-α and interleukin-6 were measured by ELISA.

Findings

CHIT-1 level in ALS-CSF samples was increased by 20-fold and it can distinguish ALS patients with a sensitivity of 87% and specificity of 83.3% at a cut off level of 1405.43 pg/ml. Enzyme activity of CHIT-1 was also 15-fold higher in ALS-CSF and has a sensitivity of 80.4% and specificity of 80% at cut off value of 0.1077989 μmol/μl/min. Combining CHIT-1 level and activity together gave a positive predictive value of 97.78% and negative predictive value of 100%. Administration of CHIT-1 increased microglial numbers and astrogliosis in the ventral horn with a concomitant increase in the levels of pro-inflammatory cytokines. Amoeboid-shaped microglial and astroglial cells were also present around the central canal. CHIT-1 administration also resulted in the reduction of motor neurons.

Conclusions

CHIT-1, an early diagnostic biomarker of sporadic ALS, activates glia priming them to attain a toxic phenotype resulting in neuroinflammation leading to motor neuronal death.

The Role of Fungi in the Etiology of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system. Infectious triggers of MS are being actively investigated. Substantial evidence supports the involvement of the Epstein-Barr virus (EBV), though other viruses, bacteria, protists, and fungi are also being considered. Many links between fungi and diseases involving chronic inflammation have been found recently. Evidence linking MS and fungi is reviewed here. The HLA-DRB1*15 allele group is the most important genetic risk factor of MS, and is a risk factor in several other conditions linked to fungal infections. Many biomarkers of MS are consistent with fungal infections, such as IL-17, chitotriosidase, and antibodies against fungi. Dimethyl fumarate (DMF), first used as an industrial fungicide, was recently repurposed to reduce MS symptoms. Its mechanisms of action in MS have not been firmly established. The low risk of MS during childhood and its moderate association with herpes simplex virus type 2 suggest genital exposure to microbes (including fungi) should be investigated as a possible trigger. Molecular and epidemiological evidence support a role for infections such as EBV in MS. Though fungal infections have not been widely studied in MS, many lines of evidence are consistent with a fungal etiology. Future microbiome and serological studies should consider fungi as a possible risk factor for MS, and future clinical studies should consider the effect of fungicides other than DMF on MS symptoms.

Science is 1% inspiration and 99% biomarkers

Neurodegeneration plays a key role in multiple sclerosis (MS) contributing to long-term disability in patients. The prognosis is, however, unpredictable coloured by complex disease mechanisms which can only be clearly appreciated using biomarkers specific to pathobiology of the underlying process. Here, we describe six promising neurodegenerative biomarkers in MS (neurofilament proteins, neurofilament antibodies, tau, N-acetylaspartate, chitinase and chitinase-like proteins and osteopontin), critically evaluating the evidence using a modified Bradford Hill criteria.

Biomarkers of multiple sclerosis: current findings

Multiple sclerosis (MS) is an autoimmune disease affecting the brain and spinal cord that is associated with chronic inflammation leading to demyelination and neurodegeneration. With the recent increase in the number of available therapies for MS, optimal treatment will be based on a personalized approach determined by an individual patient's prognosis and treatment risks. An integral part of such therapeutic decisions will be the use of molecular biomarkers to predict disability progression, monitor ongoing disease activity, and assess treatment response. This review describes current published findings within the past 3 years in biomarker research in MS, specifically highlighting recent advances in the validation of cerebrospinal fluid biomarkers such as neurofilaments (light and heavy chains), chitinases and chitinase 3-like proteins, soluble surface markers of innate immunity, and oligoclonal immunoglobulin M antibodies. Current research in circulating miRNAs as biomarkers of MS is also discussed. Continued validation and testing will be required before MS biomarkers are routinely applied in a clinical setting.

Cerebrospinal fluid biomarkers of inflammation and degeneration as measures of fingolimod efficacy in multiple sclerosis

BACKGROUND

The disease-modifying therapies (DMTs) in relapsing-remitting multiple sclerosis (RRMS) vary in their mode of action and when therapies are changed, the consequences on inflammatory and degenerative processes are largely unknown.

OBJECTIVE

We investigated the effect of switching from other DMTs to fingolimod on cerebrospinal fluid (CSF) biomarkers.

METHODS

43 RRMS patients were followed up after 4-12 months of fingolimod treatment. Concentrations of C-X-C motif chemokine 13 (CXCL13), chemokine (C-C motif) ligand 2 (CCL2), chitinase-3-like protein 1 (CHI3L1), glial fibrillary acidic protein (GFAP), neurofilament light protein (NFL), and neurogranin (NGRN) were analyzed by enzyme-linked immunosorbent assay (ELISA), while chitotriosidase (CHIT1) was analyzed by spectrofluorometry.

RESULTS

The levels of NFL, CXCL13, and CHI3L1 decreased ( p < 0.05) after fingolimod treatment. Subgroup analysis revealed a reduction in NFL ( p < 0.001), CXCL13 ( p = 0.001), CHI3L1 ( p < 0.001), and CHIT1 ( p = 0.002) in patients previously treated with first-line therapies. In contrast, the levels of all analyzed biomarkers were essentially unchanged in patients switching from natalizumab.

CONCLUSION

We found reduced inflammatory activity (CXCL13, CHI3L1, and CHIT1) and reduced axonal damage (NFL) in patients switching from first-line DMTs to fingolimod. Biomarker levels in patients switching from natalizumab indicate similar effects on inflammatory and degenerative processes. The CSF biomarkers provide an additional measure of treatment efficacy.

Cerebrospinal fluid chitinase-3-like 2 and chitotriosidase are potential prognostic biomarkers in early multiple sclerosis

BACKGROUND AND PURPOSE

The role of chitinases and chitinase-like proteins in multiple sclerosis (MS) is currently unknown; however, cerebrospinal fluid (CSF) levels of chitinase 3-like 1 (CHI3L1) predict prognosis in early MS. Whether this applies to other chitinases and chitinase-like proteins is yet to be established. Our objective was to investigate the potential of chitinase 3-like 2 (CHI3L2) and chitotriosidase as prognostic biomarkers in optic neuritis (ON) as the first demyelinating episode and to evaluate the ability of CHI3L2 to predict long-term MS risk and disability.

METHODS

In a prospective cohort of 73 patients with ON as a first demyelinating episode and 26 age-matched healthy controls levels of CHI3L2 and chitotriosidase in CSF were explored by enzyme-linked immunosorbent assay. Associations with magnetic resonance imaging white matter lesions, CSF oligoclonal bands, immunoglobulin G index and leukocyte count were investigated. Long-term MS risk and disability (Expanded Disability Status Scale, Multiple Sclerosis Functional Composite components) were examined in a retrospective cohort of 78 patients with ON as the first demyelinating episode (mean follow-up 14 years). The predictive ability of CHI3L2 was compared with CHI3L1.

RESULTS

Cerebrospinal fluid levels of CHI3L2 and chitotriosidase were significantly elevated in patients with ON and were associated with MS risk measures. CHI3L2 levels predicted MS development after ON (hazard ratio 1.95, P = 0.00039, Cox regression) and cognitive impairment by the Paced Auditory Serial Addition Test (P = 0.0357, linear regression) at follow-up. In a multivariate analysis of MS risk, CHI3L2 performed better than CHI3L1.

CONCLUSIONS

CHI3L2 and chitotriosidase are promising biomarkers in patients with a first demyelinating episode. Our findings thus support a role for these proteins as biomarkers in early MS.

Human chitotriosidase CHIT1 cross reacts with mammalian-like substrates

Humans do not synthesize chitin, yet they produce a number of active and inactive chitinases. One of the active enzymes is chitotriosidase whose serum levels are elevated in a number of diseases such as Gaucher's disease and upon fungal infection. Since the biological role of chitotriosidase in disease pathogenesis is not understood we screened a panel of mammalian GlcNAc-containing glycoconjugates as alternate substrates. LacNAc and LacdiNAc-terminating substrates are hydrolyzed, the latter with a turnover comparable to that of pNP-chitotriose. Glycolipids or glycoproteins with LacNAc and LacdiNAc represent potential chitinase substrates and the subsequent alteration of glycosylation pattern could be a factor in disease pathogenesis.

Intrathecal oligoclonal IgG synthesis in multiple sclerosis

The diagnosis of multiple sclerosis is based on dissemination in time and space. Before 2010 lack of evidence for dissemination in space could be substituted by a paraclinical test, cerebrospinal fluid (CSF) oligoclonal bands (OCBs). The present meta-analysis (13,467 patients) shows that the diagnostic specificity of OCB drops from 94% to 61% if inflammatory etiologies are considered. Importantly, this was not caused by poor laboratory practice. This review on CSF OCB further illustrates the conceptional problem of substituting dissemination in space with a biomarker. The potential prognostic value of intrathecal OCB will need to be tested prospectively.

Bacterial chitinases and chitin-binding proteins as virulence factors

Bacterial chitinases (EC 3.2.1.14) and chitin-binding proteins (CBPs) play a fundamental role in the degradation of the ubiquitous biopolymer chitin, and the degradation products serve as an important nutrient source for marine- and soil-dwelling bacteria. However, it has recently become clear that representatives of both Gram-positive and Gram-negative bacterial pathogens encode chitinases and CBPs that support infection of non-chitinous mammalian hosts. This review addresses this biological role of bacterial chitinases and CBPs in terms of substrate specificities, regulation, secretion and involvement in cellular and animal infection.

Chitotriosidase as a biomarker of cerebral adrenoleukodystrophy

Background

Adrenoleukodystrophy (ALD) is an X-linked peroxisomal disorder characterized by the abnormal beta-oxidation of very long chain fatty acids (VLCFA). In 35-40% of children with ALD, an acute inflammatory process occurs in the central nervous system (CNS) leading to demyelination that is rapidly progressive, debilitating and ultimately fatal. Allogeneic hematopoietic stem cell transplantation (HSCT) can halt disease progression in cerebral ALD (C-ALD) if performed early. In contrast, for advanced patients the risk of morbidity and mortality is increased with transplantation. To date there is no means of quantitating neuroinflammation in C-ALD, nor is there an accepted measure to determine prognosis for more advanced patients.

Methods

As cellular infiltration has been observed in C-ALD, including activation of monocytes and macrophages, we evaluated the activity of chitotriosidase in the plasma and spinal fluid of boys with active C-ALD. Due to genotypic variations in the chitotriosidase gene, these were also evaluated.

Results

We document elevations in chitotriosidase activity in the plasma of patients with C-ALD (n = 38; median activity 1,576 ng/mL/hr) vs. controls (n = 16, median 765 ng/mL/hr, p = 0.0004), and in the CSF of C-ALD patients (n = 38; median activity 4,330 ng/mL/hr) vs. controls (n = 16, median 0 ng/mL/hr, p < 0.0001). In addition, activity levels of plasma and CSF chitotriosidase prior to transplant correlated with progression as determined by the Moser/Raymond functional score 1 year following transplantation (p = 0.002 and < 0.0001, respectively).

Conclusions

These findings confirm elevation of chitotriosidase activity in patients with active C-ALD, and suggest that these levels predict prognosis of patients with C-ALD undergoing transplantation.