Assessing Chitinases and Neurofilament Light Chain as Biomarkers for Adult-Onset Leukodystrophies.

Leukodystrophies represent a large and complex group of inherited disorders affecting the white matter of the central nervous system. Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare leukodystrophy which still needs the proper identification of diagnostic, prognostic, and monitoring biomarkers. The aim of this study was to determine the diagnostic and prognostic value of chitinases and neurofilament light chain as biomarkers for ALSP. A cross-sectional study was performed to analyze cerebrospinal fluid levels of chitinases (chitotriosidase and chitinase 3-like 2) and neurofilament light chain in five different groups: (i) normal health individuals; (ii) patients with definitive diagnosis of ALSP and genetic confirmation; (iii) asymptomatic patients with CSF1R variants; (iv) patients with other adult-onset leukodystrophies; and (v) patients with amyotrophic lateral sclerosis (external control group). Chitinase levels showed a statistical correlation with clinical assessment parameters in ALSP patients. Chitinase levels were also distinct between ALSP and the other leukodystrophies. Significant differences were noted in the levels of chitinases and neurofilament light chain comparing symptomatic (ALSP) and asymptomatic individuals with CSF1R variants. This study is the first to establish chitinases as a potential biomarker for ALSP and confirms neurofilament light chain as a good biomarker for primary microgliopathies.

Plasma chitotriosidase enzyme activity as a novel therapeutic monitor for cysteamine treatment in nephropathic cystinosis: A retrospective validation study.

BACKGROUND: Cystine-depleting therapy in nephropathic cystinosis is currently monitored via the white blood cell cystine assay, although its application and usefulness are limited by practical and technical issues. Therefore, alternative biomarkers that are widely available, more economical and less technically demanding, while reliably reflecting long-term adherence to cysteamine treatment, are desirable. Recently, we proposed chitotriosidase enzyme activity as a potential novel biomarker for the therapeutic monitoring of cysteamine treatment in cystinosis. In this study, we aimed to validate our previous findings and to confirm the value of chitotriosidase in the management of cystinosis therapy. MATERIALS & METHODS: A retrospective study was conducted on 12 patients treated at the National Institutes of Health Clinical Center and followed up for at least 2 years. Plasma chitotriosidase enzyme activity was correlated with corresponding clinical and biochemical data. RESULTS: Plasma chitotriosidase enzyme activity significantly correlated with WBC cystine levels, cysteamine total daily dosage and a Composite compliance score. Moreover, plasma chitotriosidase was a significant independent predictor for WBC cystine levels, and cut-off values were established in both non-kidney transplanted and kidney transplanted cystinosis patients to distinguish patients with a good versus poor compliance with cysteamine treatment. Our observations are consistent with those of our previous study and validate our findings. CONCLUSIONS: Chitotriosidase enzyme activity is a valid potential alternative biomarker for monitoring cysteamine treatment in nephropathic cystinosis patients. SYNOPSIS: Chitotriosidase enzyme activity is a valid potential alternative biomarker for monitoring cysteamine treatment in nephropathic cystinosis patients.

Hematopoietic stem cell transplantation or enzyme replacement therapy in Gaucher disease type 3.

Gaucher disease (GD) is a lysosomal storage disorder with glucocerebroside accumulation in the macrophages. The disease is divided into three types based on neurocognitive involvement with GD1 having no involvement while the acute (GD2) and chronic (GD3) are neuronopathic. The non-neurological symptoms of GD3 are well treated with enzyme replacement therapy (ERT) which has replaced hematopoietic stem cell transplantation (HSCT). ERT is unable to prevent neurological progression as the enzyme cannot cross the blood-brain barrier. In this retrospective study, we report the general, neurocognitive, and biochemical outcomes of three siblings with GD3 after treatment with ERT or HSCT. Two were treated with HSCT (named HSCT1 and HSCT2) and one with ERT (ERT1). All patients were homozygous for the c.1448 T > C, (p.Leu483Pro) variant in the GBA1 gene associated with GD3. ERT1 experienced neurocognitive progression with development of seizures, oculomotor apraxia, perceptive hearing loss and mental retardation. HSCT1 had no neurological manifestations, while HSCT2 developed perceptive hearing loss and low IQ. Chitotriosidase concentrations were normal in plasma and cerebrospinal fluid (CSF) for HSCT1 and HSCT2, but both were markedly elevated in ERT1. We report a better neurological outcome and a normalization of chitotriosidase in the two siblings treated with HSCT compared to the ERT-treated sibling. With the advancements in HSCT over the past 25 years, we may reconsider using HSCT in GD3 to achieve a better neurological outcome and limit disease progression.

Impact of serum chitotriosidase activity on tuberculosis treatment response: single center study from Serbia.

BACKGROUND: The aim of our study was to investigate serum chitotriosidase level in tuberculosis patients, its relationship with microbiological and clinical parameters, and response to treatment. MATERIALS AND METHODS: This longitudinal panel study included 149 patients with confirmed TB disease. Serum chitotriosidase activity was measured at the beginning and the end of treatment. Factors associated with chitotriosidase activity were explored using univariate and multivariable logistic regression analysis. RESULTS: Out of 149 study participants, 71(47.7%) were female. The mean age was 53.0 (SD = 18.2). Majority of cases were new 118(79.2), predominantly 145 (97.3%) having pulmonary tuberculosis. More than half of the patients were sputum smear positive 91 (61.1%) while culture positive in 146 (98%) of them. According to radiological findings, cavitary lesions were found in 92 (63.4%) patients. Anti TB treatment was associated with significant decrease in serum chitotriosidase level (< 0.001). New TB treatment (OR = 4.41%;95% CI = 1.20-9.89), and cavitary lesions (OR = 3.86;95%CI = 0,59-26.57) were found to be significantly associated with decrease of chitotriosidase activity. CONCLUSIONS: The results of our study showed that serum chitotriosidase values are strong biomarkers for starting anti TB treatment and for treatment monitoring, since decrease in serum chitotriosidase level can predict favorable treatment response in patients with tuberculosis. Further studies are needed to explore these, and other factors associated with chitotriosidase activity among tuberculosis patients.

Enhanced levels of fractalkine and HSP60 in cerebrospinal fluid of sporadic amyotrophic lateral sclerosis patients.

Amyotrophic Lateral Sclerosis (ALS) is a multifactorial neurodegenerative disorder with a significant contribution of non-cell autonomous mechanisms to motor neuronal degeneration. Amongst a plethora of molecules, fractalkine (C-X3-C motif chemokine ligand 1), and Heat Shock Protein 60 (HSP60), are key modulators of microglial activation. The contribution of these molecules in Sporadic ALS (SALS) remains unexplored. To investigate this, fractalkine levels were estimated in Cerebrospinal fluid (CSF) of SALS patients (ALS-CSF; n = 44) by Enzyme-linked Immunosorbent Assay (ELISA) and correlated with clinical parameters including disease severity and duration. CSF HSP60 levels were estimated by Western blotting (ALS-CSF; n = 19). Also, CSF levels of Chitotriosidase-1 (CHIT-1), a microglia-specific neuroinflammatory molecule, were measured and its association, if any, with fractalkine and HSP60 was investigated. Both fractalkine and HSP60 levels were significantly elevated in ALS-CSF. Similar to our earlier observation, CHIT-1 levels were also upregulated. Fractalkine showed a moderate negative correlation with the ALS-Functional Rating Scale (ALSFRS) score indicating its significant rise in mild cases which plateaued in cases with high disease severity. However, no obvious correlation was found between fractalkine, HSP60, and CHIT-1. Our study hints that high fractalkine levels in mild cases might be conferring neuroprotection by combating microglial activation and highlights its importance as a novel therapeutic target for SALS. On the other hand, significantly enhanced levels of HSP60, a pro-inflammatory molecule, hint towards its role in accentuating microgliosis, although, it doesn't act synergistically with CHIT-1. Our study suggests that fractalkine and HSP60 act independently of CHIT-1 to suppress and accentuate neuroinflammation, respectively.

SMPD1 gene variants in patients with ß-Thalassemia major.

BACKGROUND: ß-thalassemia major and Niemann-Pick diseases have similar clinical and laboratory findings. We aimed to investigate the effects of sphingomyelin phosphodiesterase 1 (SMPD1) gene variants on the clinical and laboratory findings in patients with ß-thalassemia major. METHODS AND RESULTS: This study included 45 patients who were followed up for ß-thalassemia major in our clinic. Plasma chitotriosidase, leukocyte acid sphingomyelinase, liver enzymes, ferritin, hemogram, biochemical parameters, SMPD1 gene variant analysis, cardiac T2* MRI, and liver R2 MRI were assessed in all patients. The SMPD1 gene c.132_143del, p.A46_L49del (c.108GCTGGC[4] (p.38AL[4])) (rs3838786) variant was detected in 9 of 45 (20.0%) patients. Plasma chitotriosidase, ferritin, acetyl aminotransferase, and alanine aminotransferase levels were significantly higher in patients with the gene variant than in those without (p < 0.05). Leukocyte acid sphingomyelinase levels were significantly lower in patients with the gene variant than in those without (p < 0.05). CONCLUSION: These results imply that the clinical and laboratory findings and some features of disease progression in patients with ß-thalassemia major are similar to those of Niemann-Pick disease. They also suggest that SMPD1 gene c.132_143del, p.A46_L49del (c.108GCTGGC[4] (p.38AL[4])) (rs3838786) variant may underlie these clinical findings in patients with ß-thalassemia major.

Inhibition of Macrophage-Specific CHIT1 as an Approach to Treat Airway Remodeling in Severe Asthma.

Chitotriosidase (CHIT1) is an enzyme produced by macrophages that regulates their differentiation and polarization. Lung macrophages have been implicated in asthma development; therefore, we asked whether pharmacological inhibition of macrophage-specific CHIT1 would have beneficial effects in asthma, as it has been shown previously in other lung disorders. CHIT1 expression was evaluated in the lung tissues of deceased individuals with severe, uncontrolled, steroid-naïve asthma. OATD-01, a chitinase inhibitor, was tested in a 7-week-long house dust mite (HDM) murine model of chronic asthma characterized by accumulation of CHIT1-expressing macrophages. CHIT1 is a dominant chitinase activated in fibrotic areas of the lungs of individuals with fatal asthma. OATD-01 given in a therapeutic treatment regimen inhibited both inflammatory and airway remodeling features of asthma in the HDM model. These changes were accompanied by a significant and dose-dependent decrease in chitinolytic activity in BAL fluid and plasma, confirming in vivo target engagement. Both IL-13 expression and TGFß1 levels in BAL fluid were decreased and a significant reduction in subepithelial airway fibrosis and airway wall thickness was observed. These results suggest that pharmacological chitinase inhibition offers protection against the development of fibrotic airway remodeling in severe asthma.

Lack of Association between Serum Chitotriosidase Activity and Arterial Stiffness in Type 2 Diabetes without Cardiovascular Complications.

Chitotriosidase (CHIT), a mammalian chitinase secreted by neutrophils and activated macrophages, is increased in both cardiovascular disease (CVD) and type 2 diabetes (T2D). Arterial stiffness rises early in T2D and increases the risk of CVD. The aim of this study is to evaluate CHIT activity as an early biomarker of arterial stiffness in people with T2D free from overt vascular complications. In this cross-sectional study, arterial stiffness as measured using standard pulse wave velocity (PWV) was evaluated in 174 people with T2D without overt vascular disease. Then, we measured CHIT serum activity with an electrochemiluminescence assay in two subgroups of participants: 35 with the highest (high-PWV) and 40 with the lowest (low-PWV) PWV values. CHIT activity was no different between the low-PVW and high-PWV groups (12.7 [9.6-17.9] vs. 11.4 [8.8-15.0] nmol/mL/h, respectively). Compared with the low-PWV group, the high-PWV participants were older (p < 0.001); had a longer duration of diabetes (p = 0.03); higher ankle-brachial index ABI (p = 0.04), systolic blood pressure (p = 0.002), diastolic blood pressure (p = 0.005), fasting blood glucose (p = 0.008), and HbA1c (p = 0.005); and lower eGFR (p = 0.03) and body mass index (BMI) (p = 0.01). No association was present with sex, duration of diabetes, age, BMI, peripheral blood pressure, laboratory parameters, and glucose-lowering medications or ongoing antihypertensive therapy. Although no association was found, this study provides novel data about the association of CHIT activity with CVD, focusing on a specific outcome (arterial stiffness) in a well-defined population of subjects with T2D without established CVD.

Long-Term Evaluation of Biomarkers in the Czech Cohort of Gaucher Patients.

A personalized treatment decision for Gaucher disease (GD) patients should be based on relevant markers that are specific to GD, play a direct role in GD pathophysiology, exhibit low genetic variation, reflect the therapy, and can be used for all patients. Thirty-four GD patients treated with enzyme replacement therapy (ERT) or substrate reduction therapy (SRT) were analyzed for platelet count, chitotriosidase, and tartrate-resistant acid phosphatase activity in plasma samples, and quantitative measurement of Lyso-Gb1 was performed in dried blood spots. In our ERT and SRT study cohorts, plasma lyso-GL1 correlated significantly with chito-triosidase (ERT: r = 0.55, p < 0.001; SRT: r = 0.83, p < 0.001) and TRAP (ERT: r = 0.34, p < 0.001; SRT: r = 0.88, p < 0.001), irrespective of treatment method. A platelet count increase was associated with a Lyso-Gb1 decrease in both treatment groups (ERT: p = 0.021; SRT: p = 0.028). The association of Lyso-Gb1 with evaluated markers was stronger in the SRT cohort. Our results indicate that ERT and SRT in combination or in a switch manner could offer the potential of individual drug effectiveness for particular GD symptoms. Combination of the key biomarker of GD, Lyso-Gb1, with other biomarkers can offer improved response assessment to long-term therapy.

Chitinase Signature in the Plasticity of Neurodegenerative Diseases.

Several reports have pointed out that Chitinases are expressed and secreted by various cell types of central nervous system (CNS), including activated microglia and astrocytes. These cells play a key role in neuroinflammation and in the pathogenesis of many neurodegenerative disorders. Increased levels of Chitinases, in particular Chitotriosidase (CHIT-1) and chitinase-3-like protein 1 (CHI3L1), have been found increased in several neurodegenerative disorders. Although having important biological roles in inflammation, to date, the molecular mechanisms of Chitinase involvement in the pathogenesis of neurodegenerative disorders is not well-elucidated. Several studies showed that some Chitinases could be assumed as markers for diagnosis, prognosis, activity, and severity of a disease and therefore can be helpful in the choice of treatment. However, some studies showed controversial results. This review will discuss the potential of Chitinases in the pathogenesis of some neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis, to understand their role as distinctive biomarkers of neuronal cell activity during neuroinflammatory processes. Knowledge of the role of Chitinases in neuronal cell activation could allow for the development of new methodologies for downregulating neuroinflammation and consequently for diminishing negative neurological disease outcomes.

[The survival prediction of hospitalized patients with COVID-19: the role of chitotriosidase level in peripheral blood].

AIM: To assess the relationship between plasma chitotiosidase (CHIT) level and mortality in hospitalized patients with COVID-19. MATERIALS AND METHODS: 347 hospitalized patients with COVID-19 were enrolled in our single-center cohort prospective observational study. On the first day of hospitalization the patients were assessed by the level of CHIT in the venosus blood to addition to default laboratory examinations. The primary endpoint was all-cause death. The survival after hospital discharge were assessed via phone calls on 90 and 180 days since inclusion to the study (NCT04752085). RESULTS: Our study included 347 patients. The first symptoms appeared in 7 days [5; 7] before hospitalization; 283 (84.3%) patients had less than 50% of the involvement of the lung tissue to the inflammation process (CT 0-2); 36 (10.4%) patients had died since the start of our investigation; 30 (83.3%) of them died during hospitalization, others -no later than 60 days; 68 (19%) people didn't answer during phone call. The survivor's activity of the enzyme in the deceased was significantly lower in compare to deceased patients (90.5 [40.2; 178.0] nmol/h/mL vs 180.0 [77.2; 393.2] nmol/h/mL; p=0.001). Survivor of the patients with a higher level of the activity of the CHIT (more than 171 nmol/h/mL) was statically significantly lower. CONCLUSION: Rising of the CHIT's activity more than 171 nmol/h/mL might be an early independent predictor of the bad prognosis of the patients, who were hospitalized with COVID-19 infection.

Glucosylsphingosine (Lyso-Gb1): An Informative Biomarker in the Clinical Monitoring of Patients with Gaucher Disease.

Historically, disease burden and treatment responses in patients with Gaucher disease (GD) was assessed by monitoring clinical data, laboratory, imaging, chitotriosidase (CHITO), and other biomarkers; however, these biomarkers lack specificity and CHITO is uninformative in patients heterozygous or homozygous for the CHIT1 c.1049_1072dup24 variant. Recently, glucosylsphingosine (lyso-Gb1), a sensitive and specific GD biomarker, has been recommended for patient monitoring. Furthermore, studies measuring lyso-Gb1 and CHITO in patients on long-term treatment with enzyme replacement therapy (ERT) and/or substrate reduction therapy (SRT) reported as group data show a reduction in both analytes, yet individualized patient data are generally unavailable. We describe seven patients on long-term treatment with longitudinal clinical data with monitoring based on current treatment guidelines. We present four patients who exhibit stable disease with normalized CHITO despite elevated lyso-Gb1. We present one patient who transitioned from ERT to SRT due to lack of a clinical response with life-threatening thrombocytopenia who responded with marked improvement in platelets, and normalized levels of both CHITO and lyso-Gb1. Finally, we present two ERT to SRT switch patients with stable disease on ERT who exhibited non-compliance on SRT, one with mirrored marked elevations of CHITO and lyso-Gb1; and another with normal CHITO and platelets, but increasing lyso-Gb1 levels and enlarged spleen. These clinical vignettes highlight the role of lyso-Gb1 as a sensitive biomarker in management of patients with GD, and its further value when CHITO is normal and thus uninformative. We highlight the personalized medicine approach needed to optimize treatment outcomes and recommendations for these patients.

Chitotriosidase as a Novel Biomarker for Therapeutic Monitoring of Nephropathic Cystinosis.

BACKGROUND: Nephropathic cystinosis, a hereditary lysosomal storage disorder caused by dysfunction of the lysosomal cotransporter cystinosin, leads to cystine accumulation and cellular damage in various organs, particularly in the kidney. Close therapeutic monitoring of cysteamine, the only available disease-modifying treatment, is recommended. White blood cell cystine concentration is the current gold standard for therapeutic monitoring, but the assay is technically demanding and is available only on a limited basis. Because macrophage-mediated inflammation plays an important role in the pathogenesis of cystinosis, biomarkers of macrophage activation could have potential for the therapeutic monitoring of cystinosis. METHODS: We conducted a 2-year prospective, longitudinal study in which 61 patients with cystinosis who were receiving cysteamine therapy were recruited from three European reference centers. Each regular care visit included measuring four biomarkers of macrophage activation: IL-1ß, IL-6, IL-18, and chitotriosidase enzyme activity. RESULTS: A multivariate linear regression analysis of the longitudinal data for 57 analyzable patients found chitotriosidase enzyme activity and IL-6 to be significant independent predictors for white blood cell cystine levels in patients of all ages with cystinosis; a receiver operating characteristic analysis ranked chitotriosidase as superior to IL-6 in distinguishing good from poor therapeutic control (on the basis of white blood cell cystine levels of <2 nmol 1/2 cystine/mg protein or ≥2 nmol 1/2 cystine/mg protein, respectively). Moreover, in patients with at least one extrarenal complication, chitotriosidase significantly correlated with the number of extrarenal complications and was superior to white blood cell cystine levels in predicting the presence of multiple extrarenal complications. CONCLUSIONS: Chitotriosidase enzyme activity holds promise as a biomarker for use in therapeutic monitoring of nephropathic cystinosis.

A novel marker of systemic inflammation in psoriasis and related comorbidities: chitotriosidase

Background/aim: Chitotriosidase (ChT) is an enzyme secreted by activated macrophages and neutrophils in response to proinflammatory signals. There is growing evidence indicating that ChT activity reflects the systemic inflammatory status. This study aimed to investigate whether serum ChT activity increased in patients with psoriasis and related comorbidities. Materials and methods: This cross-sectional study included 53 (28 with associated comorbidities and 25 without comorbidities) patients with psoriasis and 52 healthy volunteers. All participants underwent laboratory investigations for serum ChT levels, complete blood count, erythrocyte sedimentation rate, C-reactive protein, and serum lipid levels. Results: The patients with psoriasis showed significantly higher levels of ChT activity as compared to the healthy controls (23.5 ± 11.4 vs. 17.5 ± 10.4 µmol/mL/hour; p = 0.015). Additionally, the ChT activity was significantly higher in patients with comorbidities than in those without (p = 0.042). Conclusion: Our data support the pathogenetic role of inflammatory processes induced by macrophage activation in patients with psoriasis and related comorbidities. We believe that high ChT activity in patients with psoriasis may serve as an early prediction of the possible related comorbidities.

Serum chitotriosidase and YKL-40 in acute pancreatitis: Reliability as prognostic marker for disease severity and correlation with inflammatory markers

Background/aim: Chitotriosidase and YKL-40, also called chitinase 3-like protein 1, are homologs of family 18 glycosyl hydrolases, secreted by human macrophages and granulocytes under inflammatory conditions. Although increased levels of chitotriosidase and YKL-40 are linked with several inflammatory diseases, the physiological utility of these two enzymes is still not fully characterized. This study aims to analyse the serum YKL-40 and chitotriosidase levels of acute pancreatitis patients to assess whether their activity correlates with acute pancreatitis and its severity. Materials and methods: Chitotriosidase and YKL-40 levels, along with routine laboratory parameters, were determined from the serum samples of 41 acute pancreatitis patients, at both onset and remission (male/female: 22/19), and 39 healthy subjects (male/female: 19/20). The Modified Glasgow Prognostic Score was used to predict the severity of the disease, and a correlation analysis was performed between study variables. Results: A statistically significant increase in both chitotriosidase and YKL-40 levels was observed in acute pancreatitis patients compared to healthy controls (P < 0.001). Higher levels of YKL-40, chitotriosidase and C-reactive protein were found in patients with acute pancreatitis at onset than in remission. The correlation analysis showed a statistically significant association between YKL-40 and chitotriosidase (p = 0.039, r = 0.323). The cut-off point for YKL-40, for detecting acute pancreatitis, was 60.3 with a sensitivity and specificity of 84.9% and 84.6% (AUC: 0.890). The optimum cut-off points for chitotriosidase, for detecting acute pancreatitis, was 33.5 with a sensitivity and specificity of 79.5% and 78.4% (AUC: 0.899). Conclusion: Elevated YKL-40 and chitotriosidase levels in acute pancreatitis patients demonstrate the importance of possible macrophage involvement in the pancreatic microenvironment during acute pancreatitis progression.

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.

Chitotriosidase: a biomarker of activity and severity in patients with sarcoidosis.

BACKGROUND: Serum chitotriosidase is a promising biomarker that has shown high specificity and sensitivity in patients with sarcoidosis. The aim of this study was to investigate correlations between serum chitotriosidase, clinical phenotypes, disease localizations and different radiological lung involvement and to identify clinical features associated with over-expression of chitotriosidase in a large cohort of sarcoidosis patients. METHODS: Chitotriosidase activity was evaluated in a population of 694 consecutive patients (males 39%, age 55.8 ± 12.8 years). Clinical and respiratory functional characteristics, Clinical Outcome Scale (COS) classification, clinical phenotypes proposed by the GenPhenResA project, and radiological assessment, including CT scan, were collected. Serum sampling and clinical and functional assessments at follow-up were also included. RESULTS: Significantly higher chitotriosidase activity was observed in sarcoidosis patients than in healthy controls (p < 0.0001). Evidence of lung fibrosis with reticular abnormalities and traction bronchiectasis at High resolution CT, presence of multiple extrapulmonary sarcoid localizations and increased 24-h urinary excretion of calcium were associated with significantly higher chitotriosidase activity (p < 0.005). Patients with remitted or minimal disease had lower values of chitotriosidase than patients with persistent disease. At follow-up, patients who required an increase in steroid dose showed an increase in its activity. CONCLUSIONS: Chitotriosidase is a reliable biomarker of sarcoidosis. It is increased in patients with sarcoidosis correlating with disease activity, severity and multiorgan dissemination. Steroid therapy tended to reduce chitotriosidase expression, however it responded in cases of disease relapse.

Cerebrospinal Fluid YKL-40 and Chitotriosidase Levels in Frontotemporal Dementia Vary by Clinical, Genetic and Pathological Subtype.

BACKGROUND: Chronic glial dysfunction may contribute to the pathogenesis of frontotemporal dementia (FTD). Cerebrospinal fluid (CSF) levels of glia-derived proteins YKL-40 and chitotriosidase are increased in Alzheimer's disease (AD) but have not been explored in detail across the spectrum of FTD. METHODS: We investigated whether CSF YKL-40 and chitotriosidase levels differed between FTD patients and controls, across different clinical and genetic subtypes of FTD, and between individuals with a clinical FTD syndrome due to AD versus non-AD (frontotemporal lobar degeneration, FTLD) pathology (based on CSF neurodegenerative biomarkers). Eighteen healthy controls and 64 people with FTD (behavioural variant FTD, n = 20; primary progressive aphasia [PPA], n = 44: nfvPPA, n = 16, svPPA, n = 11, lvPPA, n = 14, PPA-NOS, n = 3) were included. 10/64 had familial FTD, with mutations in GRN(n = 3), MAPT(n = 4), or C9orf72 (n = 3). 15/64 had neurodegenerative biomarkers consistent with AD pathology. Levels were measured by immunoassay and compared using multiple linear regressions. We also examined relationships of YKL-40 and chitotriosidase with CSF total tau (T-tau), phosphorylated tau 181 (P-tau) and ß-amyloid 1-42 (Aß42), with each other, and with age and disease du-ration. RESULTS: CSF YKL-40 and chitotriosidase levels were higher in FTD, particularly lvPPA (both) and nfvPPA (YKL-40), compared with controls. GRN mutation carriers had higher levels of both proteins than controls and C9orf72 expansion carriers, and YKL-40 was higher in MAPT mutation carriers than controls. Individuals with underlying AD pathology had higher YKL-40 and chitotriosidase levels than both controls and those with likely FTLD pathology. CSF YKL-40 and chitotriosidase levels were variably associated with levels of T-tau, P-tau and Aß42, and with each other, depending on clinical syndrome and underlying pathology. CSF YKL-40 but not chitotriosidase was associated with age, but not disease duration. CONCLUSION: CSF YKL-40 and chitotriosidase levels are increased in individuals with clinical FTD syndromes, particularly due to AD pathology. In a preliminary analysis of genetic groups, levels of both proteins are found to be highly elevated in FTD due to GRN mutations, while YKL-40 is increased in individuals with MAPT mutations. As glia-derived protein levels generally correlate with T-tau and P-tau levels, they may reflect the glial response to neurodegeneration in FTLD.

LC-MS/MS analysis of plasma glucosylsphingosine as a biomarker for diagnosis and follow-up monitoring in Gaucher disease in the Spanish population.

Background Gaucher disease (GD), caused by a deficiency in acid ß-glucosidase, leads to the accumulation of glucosylsphingosine (GluSph), which has been used as a powerful biomarker for the diagnosis and follow-up of GD. Our aim was to perform the first retrospective study of GluSph in Spanish patients, analyzing its relationship with classical biomarkers and other parameters of disease and its utility regarding treatment monitoring. Methods Classical biomarkers were evaluated retrospectively by standard methods in a total of 145 subjects, including 47 GD patients, carriers, healthy controls and patients suffering from other lysosomal lipidoses. GluSph was also measured using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method developed as part of the present study. Results The optimized method presented intra- and inter-assay variations of 3.1 and 11.5%, respectively, overall recovery higher than 96% and linearity up to plasma concentrations of 1000 ng/mL with 100% specificity and sensitivity. Only GD patients displayed GluSph levels above 5.4 ng/mL at diagnosis and this was significantly correlated with the classical biomarkers chitotriosidase (r = 0.560) and the chemokine CCL18/PARC (CCL18/PARC) (ρ = 0.515), as well as with the Spanish magnetic resonance imaging index (S-MRI, r = 0.364), whereas chitotriosidase correlated with liver volume (r = 0.372) and CCL18/PARC increased in patients with bone manifestations (p = 0.005). GluSph levels decreased with treatment in naïve patients. Conclusions Plasma GluSph is the most disease-specific biomarker for GD with demonstrated diagnostic value and responsiveness to therapy. GluSph in the present series of patients failed to demonstrate better correlations with clinical characteristics at onset than classical biomarkers.

The Role of Urinary Calcium and Chitotriosidase in a Cohort of Chronic Sarcoidosis Patients.

BACKGROUND: Calcium metabolism alterations are quite common in sarcoidosis and have been correlated with disease activity. OBJECTIVES: The aim of the study was to investigate the clinical significance of calcium metabolism alterations in patients with chronic sarcoidosis. We paid particular attention to associations with specific disease phenotypes and chitotriosidase (CTO) expression. METHODS: 212 chronic sarcoidosis patients (mean age 56.07 ± 12 years; 97 males) were retrospectively recruited. Demographic, clinical, functional, and radiological data, and serum-urinary calcium metabolism were entered into an electronical database for analysis. Levels of CTO and angiotensin-converting enzyme (ACE) were measured and bone mineral density and lung function tests were conducted. RESULTS: Hypercalciuria and hypercalcemia were observed in 18.8 and 1.8% of patients, respectively. Urinary calcium levels correlated with CTO activity (r = 0.33, p = 0.0042). Patients with worsening persistent disease showed the highest levels of urinary calcium. Diffusing capacity of the lung for carbon monoxide (DLCO) percentage correlated inversely with urinary calcium (r = 0.1482; p = 0.0397). CONCLUSIONS: Calcium metabolism alteration, particularly hypercalciuria, was observed in a significant percentage of patients of sarcoidosis. Urinary calcium was correlated with clinical status, DLCO, and serum CTO activity, suggesting its potential role as a biomarker of the activity and severity of sarcoidosis.