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.

[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.

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.

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 TGFβ1 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.

Chitotriosidase and Neopterin as Potential Biomarkers for the Evaluation of Complicated Cholecystitis-A Pilot Study

Gallstones are a common surgical pathology. Laparoscopic cholecystectomy represents the elective treatment. Complicated cases can increase the rate of conversion, the duration, and the difficulty of the intervention, along with the hospitalization period. A prospective cohort study was conducted on 51 patients with gallstones. Only subjects with normal renal, pancreatic, and hepatic functions were included. The severity of cholecystitis was evaluated by considering the ultrasound examination, intraoperative findings, and pathology report. We evaluated two potential biomarkers, namely neopterin and chitotriosidase, by comparing their levels before and after the intervention for chronic (n = 36) and complicated (n = 15) cases, as well as their eventual association with the hospitalization period. Subjects with complicated cholecystitis had significantly higher (p = 0.01) neopterin levels at presentation (16.82 nmol/L vs. 11.92 nmol/L, median values), but the differences in chitotriosidase activity between complicated (170.00 nmol/mL/h) and chronic (160.00 nmol/mL/h) cases were not significant (p = 0.66). Patients with neopterin levels above the cut-off value 14.69 nmol/L had a 3.34 times higher risk of complicated cholecystitis. Twenty-four hours after the laparoscopic cholecystectomy, the differences in neopterin level and chitotriosidase activity between chronic and complicated cases were not significant. A significant decrease in chitotriosidase activity was observed after the intervention, only for complicated cases (190 nmol/mL/h vs. 145 nmol/mL/h, p = 0.007); for neopterin, the postoperative decrease was not statistically significant (19.42 nmol/L vs. 10.92 nmol/L, p = 0.06). No significant association with the hospitalization period was observed. Neopterin may be a useful biomarker for complicated cholecystitis, and chitotriosidase may have prognostic utility in early patient follow-up.

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.

Longitudinal and Comparative Measures of Serum Chitotriosidase and YKL-40 in Patients With Idiopathic Pulmonary Fibrosis

Background

Although chitin is absent in humans, chitinases are present in healthy subjects and show dysregulated expression in a variety of diseases resulting from abnormal tissue injury and repair responses. It was shown that chitotriosidase (chitinase 1/CHIT1) and structurally-related chitinase 3-like 1 protein (CHI3L1/YKL-40) play important roles in the pathobiology of idiopathic pulmonary fibrosis (IPF), however little is known about their longitudinal serum levels and relationship to clinical measures in IPF.

Methods

The present study is the first to evaluate serial measurements of serum CHIT1 activity and YKL-40 concentrations in patients with IPF starting antifibrotic treatment and followed up for 24 months. In addition, baseline serum CHIT1 and YKL-40 were compared between patients with IPF and control subjects, and possible CHIT1 and YKL-40 relationships to longitudinal clinical assessments in IPF were explored.

Results

Baseline serum CHIT1 activity and YKL-40 concentrations were significantly elevated in patients with IPF compared to control subjects and showed similar discriminatory ability in distinguishing IPF from controls. No significant differences between the median serum CHIT1 activity and YKL-40 concentration measured over a study follow-up were noted. We found significantly elevated baseline serum CHIT1 activity in the progressors compared with the stables in the first year, while significantly increased baseline serum CHIT1 activity was noted in the stables compared to the progressors in the second year. Additionally, we observed a significant negative correlation between a change in serum YKL-40 concentration and a change in forced vital capacity (FVC) % predicted (% pred.) in the stables subgroup, whereas, a change in serum CHIT1 activity correlated negatively with a change in FVC% pred. in the progressors subgroup.

Conclusions

This explorative study findings add further evidence that CHIT1 and YKL-40 are upregulated in patients with IPF, and suggest that longitudinally stable serum CHIT1 activity and YKL-40 concentration levels may potentially be associated with the antifibrotic treatment response. In addition, our findings are supporting the possible role of CHIT1 and YKL-40 as candidate diagnostic and prognostic biomarkers in IPF. Further research is needed to validate present study findings.

INNATE IMMUNE FUNCTION IN LAKE ERIE WATERSNAKES (NERODIA SIPEDON INSULARUM) WITH OPHIDIOMYCOSIS

Ophidiomycosis, caused by the fungus Ophidiomyces ophidiicola, poses a threat to the health of wild and managed snakes worldwide. Variation in snake innate immunity, the primary defense against infection in reptiles, may explain the observed variation in ophidiomycosis clinical disease severity among snakes. In this study, two components of the innate immune response were examined in snake plasma. We investigated whether complement activity, as measured by sheep red blood cell hemolysis, and chitotriosidase activity were associated with ophidiomycosis disease severity and time in captivity in Lake Erie watersnakes (Nerodia sipedon insularum). There was no difference in complement-mediated hemolysis or chitotriosidase activities between snakes with varying levels of ophidiomycosis clinical severity sampled in the field. However, among snakes with skin lesions kept in captivity, chitotriosidase activity was significantly higher in snakes with mild disease, compared with snakes with severe disease, and hemolysis activity increased with time in captivity. Overall, Lake Erie watersnakes had higher complement activity, but lower chitotriosidase activity, compared with other reptile species. To our knowledge, this study is the first to describe chitotriosidase activity in a snake species. These results provide mixed evidence of associations between innate immune function and ophidiomycosis severity, and more work is needed to investigate differences among snake species.

Nephropathic Cystinosis: Pathogenic Roles of Inflammation and Potential for New Therapies

The activation of several inflammatory pathways has recently been documented in patients and different cellular and animal models of nephropathic cystinosis. Upregulated inflammatory signals interact with many pathogenic aspects of the disease, such as enhanced oxidative stress, abnormal autophagy, inflammatory cell recruitment, enhanced cell death, and tissue fibrosis. Cysteamine, the only approved specific therapy for cystinosis, ameliorates many but not all pathogenic aspects of the disease. In the current review, we summarize the inflammatory mechanisms involved in cystinosis and their potential impact on the disease pathogenesis and progression. We further elaborate on the crosstalk between inflammation, autophagy, and apoptosis, and discuss the potential of experimental drugs for suppressing the inflammatory signals in cystinosis.

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.

The Use of Chitotriosidase as a Marker of Active Sarcoidosis and in the Diagnosis of Fever of Unknown Origin (FUO)

Sarcoidosis is a multi-organ inflammatory granulomatosis with a lung-predominant involvement. The aim of this study was to investigate the use of serum chitotriosidase (CHIT1) in patients with fever of unknown origin (FUO); the patients with confirmed diagnosis of active sarcoidosis were compared with ones affected by inactive or treated sarcoidosis. CHIT1 activity was evaluated in 110 patients initially admitted at the hospital as FUOs. The overall performance of CHIT1 for active sarcoidosis diagnosis was assessed by performing an area under the receiver operating characteristic curve analysis (AUROC). The sarcoidosis patients were significantly older than the FUO patients not affected by sarcoidosis (p < 0.01). CHIT1 showed a good accuracy as a biomarker for active sarcoidosis in patients explored for FUO (AUROC 0.955; CI 95% 0.895–0.986; p < 0.001). A CHIT1 value >90.86 showed 96.8% sensitivity (84.2–99.9) and 85.5% specificity (75–92.8) in discriminating active sarcoidosis from other causes of FUO. CHIT1 significantly discriminated active versus inactive/under treatment sarcoidosis patients (with lower enzyme activity) (ROC analysis, sensitivity: 96.9%, specificity: 94.7%, value >83.01 nmol/mL/h, AUROC: 0.958, 0.862–0.994, p < 0.001) compared to ACE (ROC analysis, sensitivity: 25.8%, specificity: 93.7%, value >65 UI/L). In conclusion, CHIT1 is a reliable/sensitive biomarker of active sarcoidosis, with values significantly decreasing in remitted/treated patients. It significantly discriminates active sarcoidosis from FUO patients, providing a useful tool in the diagnosis-assessing process.

Chitotriosidase as biomarker for early stage amyotrophic lateral sclerosis: a multicenter study

Objective: Levels of chitotriosidase (CHIT1) are increased in the cerebrospinal fluid (CSF) of amyotrophic lateral sclerosis (ALS) patients reflecting microglial activation. Here, we determine the diagnostic and prognostic potential of CHIT1 for early symptomatic ALS. Methods: Overall, 275 patients from 8 European neurological centers were examined. We included ALS with <6 and >6 months from symptom onset, other motoneuron diseases (oMND), ALS mimics (DCon) and non-neurodegenerative controls (Con). CSF CHIT1 levels were analyzed for diagnostic power and association with progression and survival in comparison to the benchmark neurofilament. The 24-bp duplication polymorphism of CHIT1 was analyzed in a subset of patients (N = 65). Results: Homozygous CHIT1 duplication mutation carriers (9%) invariably had undetectable CSF CHIT1 levels, while heterozygous carriers had similar levels as patients with wildtype CHIT1 (p = 0.414). In both early and late symptomatic ALS CHIT1 levels was increased, did not correlate with patients' progression rates, and was higher in patients diagnosed with higher diagnostic certainty. Neurofilament levels correlated with CHIT1 levels and prevailed over CHIT1 regarding diagnostic performance. Both CHIT1 and neurofilaments were identified as independent predictors of survival in late but not early symptomatic ALS. Evidence is provided that CHIT1 predicts progression in El Escorial diagnostic category in the group of ALS cases with a short duration. Conclusions: CSF CHIT1 level may have additional value in the prognostication of ALS patients with a short history of symptoms classified in diagnostic categories of lower clinical certainty. To fully interpret apparently low CHIT1 levels knowledge of CHIT1 genotype is needed.

Evaluation of Chitotriosidase and Neopterin as Biomarkers of Microvascular Complications in Patients with Type 1 Diabetes Mellitus

The chronic complications of diabetes mellitus (DM) are accompanied by inflammatory manifestations. Our study aimed to evaluate a possible association between the inflammatory status (reflected by serum chitotriosidase and neopterin) and the timely evolution and occurrence of chronic microvascular complications in patients with type 1 DM. This observational, cross-sectional study included 82 type 1 DM patients from the Centre for Diabetes, Nutrition and Metabolic Diseases, Cluj-Napoca, Romania. Our results demonstrated a link between the extent of inflammation, evaluated by the enzymatic activity of circulating chitotriosidase, and the onset of microvascular complications, especially diabetic neuropathy and retinopathy. Chitotriosidase enzymatic activity showed an ascending evolution over time. In non-smoking patients, the increase in chitotriosidase activity was correlated with the extent of microalbuminuria and the decline of glomerular filtration rate, while in smokers, only the presence of a positive correlation between chitotriosidase activity and disease progression was noticed. According to our results, the time span between the moment of diagnosis and the onset of microvascular complications was longer in non-smokers than in smokers. These results also imply that increased chitotriosidase activity may be a predictor of endothelial dysfunction in type 1 DM.

Milk Replacer Supplementation with Docosahexaenoic Acid from Microalgae Does Not Affect Growth and Immune Status in Goat Kids

Simple Summary

The consumption of docosahexaenoic acid (DHA) has beneficial effects on human health. Meat from suckling goat kids is highly valuable, especially in Mediterranean countries. Based on this, several strategies have been implemented to increase the content of DHA in foodstuffs such as meat and meat products. Several studies have observed how feeding diverse sources of DHA can improve the fatty acid profile in goat kid meat. However, few studies have focused on the effect of using these DHA supplements on growth and the immune system development in these animals. Consequently, this study aimed to evaluate the effect of different levels of DHA supplementation on growth and the immune system development in newborn goat kids. The current study showed that the DHA supplementation did not affect either growth or the immune status of goat kids during the first 35 days of life.

Abstract

Consumption of polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA), has beneficial effects for consumers’ health. Consequently, there is an increased interest in enhancing meat fatty acid profiles (i.e., PUFA and DHA content) through diverse nutritional strategies. This study aimed to investigate the effect of supplementing a microalgae-derived product rich in DHA on growth and immune system development in newborn goat kids. In this experiment, newborn goat kids were fed milk replacer (MR) supplemented with three levels of a microalgae-derived product rich in DHA (DHA-Gold^®, Martek Biosciences, MD, USA). Groups were designed as follows: MR-NS (milk replacer without DHA-Gold^® supplementation; n = 10), MR-DHA-9 (9 g of DHA-Gold^®/L milk replacer; n = 10) and MR-DHA-18 (18 g of DHA-Gold^®/L milk replacer; n = 10). The immune status of the kids was evaluated by the plasma IgG and IgM concentrations, as well as by the complement system and chitotriosidase activities. Dietary supplementation with DHA did not affect either growth or innate and humoral immunity (p > 0.05). This study concludes that supplementation with DHA does not cause negative effects on growth and immune status in newborn goat kids.

Expression of Chitotriosidase in Macrophages Modulates Atherosclerotic Plaque Formation in Hyperlipidemic Mice

Objective

To determine whether overexpression of the chitin degrading enzyme, chitotriosidase (CHIT1), modulates macrophage function and ameliorates atherosclerosis.

Approach and Results

Using a mouse model that conditionally overexpresses CHIT1 in macrophages (CHIT1-Tg) crossbred with the Ldlr ^-/- mouse provided us with a means to investigate the effects of CHIT1 overexpression in the context of atherosclerosis. In vitro, CHIT1 overexpression by murine macrophages enhanced protein expression of IL-4, IL-8, and G-CSF by BMDM upon stimulation with a combination of lipopolysaccharide (LPS) and interferon-γ (IFN-γ). Phosphorylation of ERK1/2 and Akt was also down regulated when exposed to the same inflammatory stimuli. Hyperlipidemic, Ldlr ^-/--CHIT1-Tg (CHIT1-OE) mice were fed a high-fat diet for 12 weeks in order to study CHIT1 overexpression in atherosclerosis. Although plaque size and lesion area were not affected by CHIT1 overexpression in vivo, the content of hyaluronic acid (HA) and collagen within atherosclerotic plaques of CHIT1-OE mice was significantly greater. Localization of both ECM components was markedly different between groups.

Conclusions

These data demonstrate that CHIT1 alters cytokine expression and signaling pathways of classically activated macrophages. In vivo, CHIT1 modifies ECM distribution and content in atherosclerotic plaques, both of which are important therapeutic targets.

Chitinases and Chitinase-Like Proteins in Obstructive Lung Diseases - Current Concepts and Potential Applications

Chitinases, enzymes that cleave chitin’s chain to low molecular weight chitooligomers, are widely distributed in nature. Mammalian chitinases belong to the 18-glycosyl-hydrolase family and can be divided into two groups: true chitinases with enzymatic activity (AMCase and chitotriosidase) and chitinase-like proteins (CLPs) molecules which can bind to chitin or chitooligosaccharides but lack enzymatic activity (eg, YKL-40). Chitinases are thought to be part of an innate immunity against chitin-containing parasites and fungal infections. Both groups of these hydrolases are lately evaluated also as chemical mediators or biomarkers involved in airway inflammation and fibrosis. The aim of this article is to present the current knowledge on the potential role of human chitinases and CLPs in the pathogenesis, diagnosis, and course of obstructive lung diseases. We also assessed the potential role of chitinase and CLPs inhibitors as therapeutic targets in chronic obstructive pulmonary disease and asthma.

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-1β, 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.

Increased Chitotriosidase Is Associated With Aspergillus and Frequent Exacerbations in South-East Asian Patients With Bronchiectasis

BACKGROUND

Chitinase activity is an important innate immune defence mechanism against infection that includes fungi. The 2 human chitinases: chitotriosidase (CHIT1) and acidic mammalian chitinase are associated to allergy, asthma, and COPD; however, their role in bronchiectasis and bronchiectasis-COPD overlap (BCO) is unknown.

RESEARCH QUESTION

What is the association between chitinase activity, airway fungi and clinical outcomes in bronchiectasis and bronchiectasis-COPD overlap?

STUDY DESIGN AND METHODS

A prospective cohort of 463 individuals were recruited across five hospital sites in three countries (Singapore, Malaysia, and Scotland) including individuals who were not diseased (n = 35) and who had severe asthma (n = 54), COPD (n = 90), bronchiectasis (n = 241) and BCO (n = 43). Systemic chitinase levels were assessed for bronchiectasis and BCO and related to clinical outcomes, airway Aspergillus status, and underlying pulmonary mycobiome profiles.

RESULTS

Systemic chitinase activity is elevated significantly in bronchiectasis and BCO and exceed the activity in other airway diseases. CHIT1 activity strongly predicts bronchiectasis exacerbations and is associated with the presence of at least one Aspergillus species in the airway and frequent exacerbations (≥3 exacerbations/y). Subgroup analysis reveals an association between CHIT1 activity and the "frequent exacerbator" phenotype in South-East Asian patients whose airway mycobiome profiles indicate the presence of novel fungal taxa that include Macroventuria, Curvularia and Sarocladium. These taxa, enriched in frequently exacerbating South-East Asian patients with high CHIT1 may have potential roles in bronchiectasis exacerbations.

INTERPRETATION

Systemic CHIT1 activity may represent a useful clinical tool for the identification of fungal-driven "frequent exacerbators" with bronchiectasis in South-East Asian populations.

Chitotriosidase Levels in the Colostrum from Mothers of Term and Preterm Infants

Background: Breast milk Chitotriosidase (Chit 1) shows antifungal effect and has an active role in the natural immune response against certain pathogens. The aim of this study was to compare colostrum Chit 1 levels from mothers of term and preterm infants. Materials and Methods: The study included 72 mothers of 32 preterm and 40 term infants (gestational age; 33.7 ± 1.8 vs. 39.1 ± 1.1 weeks, birth weight; 1931.7 ± 539.8 vs. 3350.9 ± 419.7 g). Breast milk samples were taken at postnatal 24-48 hours. Chit 1 level was evaluated with the quantitative calorimetric method. Results: No significant difference was determined between the term and preterm groups in terms of maternal age, education level, weight gain in pregnancy, and body mass index (BMI). The median colostrum Chit 1 level was higher in the preterm group, but the difference was not statistically significant between two groups (p = 0.43). There is no association between colostrum Chit 1 level, maternal age, gravida, BMI, infant gender, income level, and pre-eclampsia. The colostrum Chit 1 level of mothers who had weight gain exceeding the recommended limits was significantly lower than mothers with weight gain within the recommended limits in the term group (4346.2 vs. 4914.2, p = 0.021). A negative correlation was determined between the birthweight of term infants and the colostrum Chit 1 levels (p = 0.045, r = -0.319). Conclusion: Although the data need to be validated by further investigation, the observations made in this study seem to indicate that colostrum Chit-1 may have role in the protection of preterm infants.

Overexpression of chitotriosidase and YKL-40 in peripheral blood and sputum of healthy smokers and patients with chronic obstructive pulmonary disease

Background

Despite the absence of endogenous chitin in humans, chitinases are present in the serum of healthy subjects and their levels are increased in a variety of chronic inflammatory conditions. It has been shown that chitotriosidase and structurally related chitinase-like protein-YKL-40 contribute to the pathogenesis of COPD. However, details regarding the relation of their systemic and local airways levels remain unknown.

Objectives

To examine peripheral blood and sputum chitotriosidase and YKL-40 expression in smokers and patients with COPD.

Methods

Forty patients with COPD, 20 healthy smokers and 10 healthy never-smokers were studied. Serum and induced sputum chitotriosidase protein and activity levels, YKL-40 concentrations, and their gene expression in sputum cells and peripheral blood mononuclear cells (PBMC) were evaluated.

Results

Both chitotriosidase protein levels and activity were higher in sputum obtained from COPD subjects compared to healthy never-smokers (P<0.05 and P<0.01, respectively). A similar pattern was observed for PBMC chitotriosidase mRNA expression (P<0.001). YKL-40 serum concentrations were elevated in healthy smokers and COPD subjects compared to healthy never-smokers (P<0.001 and P<0.01, respectively). In sputum, YKL-40 levels were increased in COPD compared to healthy never-smokers (P<0.01). PBMC YKL-40 mRNA expression was increased in COPD and healthy smokers compared to healthy never-smokers (P<0.0001). No associations were found between chitotriosidase or YKL-40 peripheral blood levels and sputum levels.

Conclusions

Our results demonstrate that chitotriosidase and YKL-40 are overexpressed in peripheral blood and airways in both healthy smokers and COPD subjects which may indicate smoking-related activation of macrophages, neutrophils, and epithelial cells.

Sheep and goats raised in mixed flocks have diverse immune status around parturition

Several physiological and metabolic changes take place in dairy ruminants around parturition (late pregnancy, parturition, and early lactation). Dairy species are genetically selected for their higher milk production compared with non-dairy species. This fact causes a constant stress that impairs the immune status of the animal, with consequences for its welfare and performance. In the present study, we assessed the immune status of high-yield dairy sheep and goats by quantifying IgG and IgM concentrations, as well as chitotriosidase (ChT) and complement system [total complement system (TC) and alternative complement pathway (AC)] activity in blood plasma around parturition. We also measured IgG and IgM concentrations and ChT activity in colostrum and milk during the first 40 d postpartum. The lowest blood IgG concentration was at parturition in both species. We detected no differences in blood IgG concentrations between species. Blood IgM concentrations were constant in both species throughout the study period. However, blood IgM concentrations were greater in sheep than in goats. Blood ChT activity was greater in goats than in sheep, and both species showed constant activity of this enzyme throughout the study period. We observed no differences in complement system (TC and AC) activity between sheep and goats. In addition, both TC and AC activity were constant in both species throughout the experiment. In general, IgG and IgM concentrations were greater in sheep colostrum than in goat colostrum, but these differences disappeared after d 4 (IgG) and d 3 (IgM) postpartum. In both species, the highest IgG and IgM concentrations were measured in colostrum, gradually decreasing during the first days postpartum. Chitotriosidase activity decreased in both species from colostrum to milk, although goats always showed greater ChT activity than sheep. Both sheep and goats seemed to be more susceptible to infectious diseases around parturition. As well, goats showed greater ChT activity in blood, colostrum, and milk than sheep. This fact may give these animals additional protection against parasite and fungal infections.

The Genetic Polymorphisms of 24 Base Pair Duplication and Point G102S of Human Chitotriosidase to Bancroftian Filariasis at the Thai⁻Myanmar Border

Lymphatic filariasis, caused by lymphatic filarial parasites, Wuchereria bancrofti, and Brugia malayi, causes significant morbidity and disability to 120 million people in the tropics and subtropics. Chitin has an important role for embryogenesis in adult worms and is a component of microfilaria sheath. Human chitotriosidase (CHIT1) is a chitin-degrading enzyme which provides a protective role against chitin-containing pathogens. Here, we determined the association of CHIT1 polymorphisms with susceptibility to bancroftian filariasis (BF) in 88 individuals at the Thai–Myanmar border. Two common polymorphisms of CHIT1, contributing inactive CHIT protein, including 24 base pair (24 bp) duplication in exon 10, and p. G102S in exon 4 were genotyped by allele-specific Polymerase Chain Reaction (PCR) and PCR sequencing, respectively. Unexpectedly, genotype frequencies of 24 bp duplication insertion homozygous (INS/INS) were significantly higher in endemic normal (EN) (40.0%) than BF patients (31.4%). In contrast, genotype frequencies of p. G102S homozygous (A/A) in BF patients (21.6%) was higher than in EN (19.0%) without statistical difference. Mutant allele frequencies of 24 bp duplication were 0.6125 (98/160) and p. G102S were 0.392 (69/176). Genotype and allele frequencies of CHIT1, 24 bp duplication, and p. G102S, showed no association with BF patients.

Serum chitotriosidase and neopterin levels in patients with ankylosing spondylitis

Background:

The aim of this study was to assess the serum chitotriosidase (ChT) and neopterin levels in patients with ankylosing spondylitis (AS) and to evaluate whether serum ChT and neopterin levels are related to disease activity.

Methods:

A total of 86 patients with AS were included in the study. Patients were divided into two groups based on Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores: The active AS patients group included 40 patients who had a BASDAI score ⩾4. The inactive AS patients group included 46 patients who had a BASDAI score <4. We compared the serum level of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), ChT and neopterin between the two groups.

Results:

Active AS patients had significantly higher ESR, CRP, serum ChT and neopterin levels compared with the inactive AS patients group (p < 0.05). Positive correlations were found between serum ChT levels and ESR (r = 0.87, p = 0.005), and CRP levels (r = 0.86, p = 0.006). Also, there was a positive significant correlation between serum ChT levels and BASDAI scores (r = 0.67, p = 0.03). No correlation was found between serum neopterin levels and the BASDAI scores, ESR, and CRP levels (p > 0.05). Higher disease activity (BASDAI score ⩾4) was found to be associated with ChT (p = 0.012) in the multiple logistic regression analysis.

Conclusion:

The present study emphasized that serum ChT levels can be useful in the determination of the disease activity of AS patients.

Bone manifestations in neuronopathic Gaucher disease while receiving high-dose enzyme replacement therapy

Avascular necrosis (AVN), one type of bone infarction, is a major irreversible complication of Gaucher disease (GD). In this report, two pediatric patients with GD type 3, homozygous for the L483P pathogenic variant (formerly L444P), developed AVN despite treatment on long-term, high-dose enzyme replacement therapy (ERT). ERT was initiated in both patients, who had intact spleens, shortly after diagnosis with an initial dramatic response. However, both patients exhibited AVN after 5.5 and 11 years on high-dose ERT, respectively, despite good compliance and normalized hematological findings and visceral symptoms. This report demonstrates the importance of careful, regular surveillance of the musculoskeletal system in addition to monitoring the neurological symptoms associated with neuronopathic GD. Additionally, it highlights the limitations of ERT in terms of targeting certain sanctuary sites such as bone marrow and suggests the need for new treatment modalities other than ERT monotherapy to address these limitations.

Chitotriosidase inhibits allergic asthmatic airways via regulation of TGF-β expression and Foxp3+ Treg cells

BACKGROUND

Chitotriosidase (chitinase 1, Chit1), a major true chitinase in humans, is induced in childhood asthma and has been implicated in the pathogenesis of a variety of inflammatory and tissue remodeling responses. However, the role and the mechanisms that underlie these contributions to the diseases have not been defined. We hypothesized that Chit1 plays a significant role in the pathogenesis of allergic asthma.

METHODS

Wild-type and Chit1-deficient mice and cells in culture were used to define the roles of Chit1 in models of allergic adaptive Th2 inflammation. In addition, the levels of sputum Chit1 were evaluated in pediatric asthma patients and compared to control.

RESULTS

The levels of sputum Chit1 were significantly increased in the patients with childhood asthma. Mice with Chit1 null mutation demonstrated enhanced allergic Th2 inflammatory and cytokine and IgE responses to OVA or house dust mite allergen sensitization and challenge. However, the expression levels of TGF-β1 were significantly decreased with a diminished number of Foxp3+ regulatory T cells (Treg) in the lungs of Chit1-/- mice compared to WT controls. In vitro, the absence of Chit1 significantly reduced TGF-β-stimulated conversion of CD4+ CD25- naïve T cells to CD4+ Foxp3+ Treg cells, suggesting Chit1 is required for optimal effect of TGF-β1 in Treg cell differentiation.

CONCLUSION

Chit1 plays a protective role in the pathogenesis of allergic inflammation and asthmatic airway responses via regulation of TGF-β expression and Foxp3+ Treg cells.

Chitins and chitinase activity in airway diseases

Chitin, one of the most abundant biopolymers on Earth, is bound and degraded by chitinases, specialized enzymes that are similarly widespread in nature. Chitin catabolism affects global carbon and nitrogen cycles through a host of diverse biological processes, but recent work has focused attention on systems of chitin recognition and degradation conserved in mammals, connecting an ancient pathway of polysaccharide processing to human diseases influenced by persistent immune triggering. Here we review current advances in our understanding of how chitin-chitinase interactions affect mucosal immune feedback mechanisms essential to maintaining homeostasis and organ health.

Serum chitotriosidase: a circulating biomarker in polycythemia vera

OBJECTIVES

Serum chitotriosidase activity (CHIT1) is a biomarker of macrophage activation with an important role in inflammation-induced tissue remodeling and fibrosis. Macrophages have been described to play a crucial role in regulating pathological erythropoiesis in polycythemia vera (PV). The aim of this study was to evaluate CHIT1 in patients diagnosed with Philadelphia-negative myeloproliferative neoplasms (MPNs).

METHODS

Using fluorometric assay, we measured CHIT1 in 28 PV, 27 essential thrombocythemia (ET), 17 primary myelofibrosis (PMF), 19 patients with secondary myelofibrosis and in 25 healthy controls.

RESULTS

CHIT1 was significantly higher in PV (p < .001) and post-PV myelofibrosis (MF) transformation (post-PV MF) (p = .020), but not in ET (p = .080), post-ET MF transformation (p = .086), and PMF patients (p = .287), when compared to healthy controls. CHIT1 in PV was positively correlated with hemoglobin (p = .026), hematocrit (p = .012), absolute basophil count (p = .030) and the presence of reticulin fibrosis in the bone marrow (p = .023).

DISCUSSION

A positive correlation between CHIT1 and these distinct laboratory PV features might imply macrophages closely related to clonal erythropoiesis as cells of CHIT1 origin. In addition, a positive association between CHIT1 and reticulin fibrosis might indicate its potential role in PV progression.

CONCLUSION

CHIT1 might be considered as a circulating biomarker in PV. Additional studies are needed to clarify the role of CHIT1 in promoting disease progression and bone marrow fibrosis in PV.

Chitinase mRNA Levels Determined by QPCR in Crab-Eating Monkey (Macaca fascicularis) Tissues: Species-Specific Expression of Acidic Mammalian Chitinase and Chitotriosidase

Mice and humans express two active chitinases: acidic mammalian chitinase (AMCase) and chitotriosidase (CHIT1). Both chitinases are thought to play important roles in specific pathophysiological conditions. The crab-eating monkey (Macaca fascicularis) is one of the most frequently used nonhuman primate models in basic and applied biomedical research. Here, we performed gene expression analysis of two chitinases in normal crab-eating monkey tissues by way of quantitative real-time polymerase chain reaction (qPCR) using a single standard DNA molecule. Levels of AMCase and CHIT1 messenger RNAs (mRNAs) were highest in the stomach and the lung, respectively, when compared to other tissues. Comparative gene expression analysis of mouse, monkey, and human using monkey–mouse–human hybrid standard DNA showed that the AMCase mRNA levels were exceptionally high in mouse and monkey stomachs while very low in the human stomach. As for the CHIT1 mRNA, we detected higher levels in the monkey lung when compared with those of mouse and human. The differences of mRNA expression between the species in the stomach tissues were basically reflecting the levels of the chitinolytic activities. These results indicate that gene expression of AMCase and CHIT1 differs between mammalian species and requiring special attention in handling data in chitinase-related studies in particular organisms.

Chitotriosidase, a marker of innate immunity, is elevated in patients with primary breast cancer

BACKGROUND

Cancer progression has been associated with altered immune cell function and activation. Neopterin, which is secreted by interferon-γ stimulated macrophages, exhibits an association with multiple cancer types and metastatic disease. Chitotriosidase, which is secreted by chronically activated macrophages and granulocyte-macrophage colony-stimulating factor stimulated neutrophils has not been studied in the setting of cancer.

OBJECTIVE

The goal of this discovery study was to screen chitotriosidase for diagnostic capacity in detecting cancer and compare its operating characteristics with those of neopterin.

METHODS

Serum from subjects with breast (n= 66) or prostate (n= 70) cancer, and from 204 subjects free of malignant disease were studied. Chitotriosidase was measured by enzyme activity assay, while neopterin was measured by a competitive enzyme immunoassay. Statistical analyses included group comparisons by Mann Whitney U test, diagnostic capacity by receiver operating characteristics (ROC) curve analysis and biomarker associations with physiologic and clinical measures by Spearman correlation.

RESULTS

Chitotriosidase activity was significantly higher in both cancer types compared with gender matched controls, though only in breast cancer was the diagnostic capacity significant (area under the ROC curve of 0.97 ± 0.01). In contrast, neopterin was significantly elevated in prostate cancer and exhibited discriminatory capacity (area under the ROC curve of 0.76 ± 0.05). Age, BMI, % body fat and metastasis were variables that correlated with neopterin, but not chitotriosidase levels.

CONCLUSIONS

The operating characteristics of serum chitotriosidase were different from neopterin and further analysis of chitotriosidase as a biomarker for breast cancer is warranted.

Evaluation of Chitotriosidase as a Marker of Inflammatory Status in Critical Limb Ischemia

BACKGROUND

Chitotriosidase is an enzyme secreted by activated macrophages. This study aims to investigate the usefulness of circulating chitotriosidase activity as a marker of inflammatory status in patients with critical limb ischemia (CLI).

MATERIALS AND METHODS

An observational gender-matched case-control study was conducted on patients hospitalized with the primary diagnosis of CLI, as well as a control group. The control group consisted of healthy volunteers.

RESULTS

Forty-three patients were included in each group. Similar demographic characteristics (median age of 60-62 years and overweight) were observed in both groups. Chitotriosidase activity ranged from 110 nmol/ml/hr to 1530 nmol/ml/hr in the CLI group and from 30 nmol/ml/hr to 440 nmol/ml/hr in the control group; demonstrating significantly elevated values in the CLI group (p<0.001). Median plasma chitotriosidase activity was significantly elevated in smokers compared with non-smokers in both groups (p<0.05). However, this activity had higher values in CLI than in control subjects. Receiver operating characteristic (ROC) analysis was then performed in order to verify the diagnostic accuracy of chitotriosidase as an inflammatory biomarker in CLI.

CONCLUSION

Circulating chitotriosidase is a test which can potentially be used for the monitoring of CLI patients without other inflammatory conditions. However, the interpretation of elevated values must take into account the inflammatory response induced by tobacco exposure.

NLRP3 expression and urinary HSP72 in relation to biomarkers of inflammation and oxidative stress in diabetic nephropathy patients

Diabetic nephropathy (DN) is one of the major causes of end-stage renal disease. Nod-like receptors nucleotide-binding domain and leucine-rich repeat pyrin-3 domain (NLRP3) inflammasome displays a considerable role in the chronic inflammatory state observed in diabetic patients. Urinary heat shock protein 72 (uHSP72) is a sensitive and specific biomarker for the early detection of acute kidney injury. The aim of this study was to evaluate NLRP3 relative gene expression, its correlation with inflammatory and oxidative stress markers, and to assess the value of uHSP72 in the early detection of DN in type 2 diabetic patients with different degrees of DN. Forty-five type 2 diabetic patients: 15 normoalbuminuric, 15 microalbuminuric, 15 macroalbuminuric, in addition to 15 healthy controls were enrolled in this study. Clinical examination and routine laboratory investigations were performed. NLRP3 mRNA expression was assessed by real time polymerase chain reaction. Serum 8-hydroxy-2'-deoxyguanosine (8-OHdG), interleukin 1β (IL-1β), and uHSP72 levels were estimated by enzyme-linked immunosorbent assay. Serum chitotriosidase (CHIT1) activity was examined. NLRP3 mRNA relative expression, serum levels of 8-OHdG, IL-1β, and uHSP72, in addition to CHIT 1 activity were significantly increased in the macroalbuminuric patient group as compared to control and the other two diabetic groups. Also, a significant positive correlation was documented between the previously mentioned parameters and urinary albumin/creatinine ratio, serum creatinine, and HbA1c. Multiple linear regression analysis using urinary albumin/creatinine ratio as dependent variable confirmed that uHSP72 and NLRP3 mRNA relative expression were the independent predictors of DN (β were 0.432 and 0.448 respectively, P < 0.001). Receiver operating characteristic analyses revealed that both NLRP3 mRNA relative expression and uHSP72 levels were useful biomarkers discriminating DN patients from patients with type 2 diabetes mellitus (AUC were 0.957 and 0.983, respectively). uHSP72 may be considered as a novel potential diagnostic biomarker for the early detection of DN. Moreover, these data support the pivotal role of NLRP3 in the development and progression of DN. © 2017 IUBMB Life, 69(8):623-630, 2017.

Chitotriosidase enzyme activity: is this a possible chronic inflammation marker in children with common variable immunodeficiency and early atherosclerosis?

Background Common variable immunodeficiency is a rare clinically symptomatic primary immunodeficiency disorder which manifests a wide variability of symptoms, complications. Atherosclerosis in common variable immunodeficiency patients has not been investigated yet contrary to other severe clinical complications. We aimed to investigate the chitotriosidase enzyme's role as an inflammation and atherosclerosis marker in paediatric common variable immunodeficiency patients. Methods Common variable immunodeficiency patients (n = 24) and healthy controls (n = 23) evaluated for chitotriosidase activity with other inflammation markers (hsCRP, myeloperoxidase, serum amyloid A, ferritin), lipid profile and echocardiographic findings (carotid artery intima media thickness - cIMT, brachial artery flow-mediated vazodilatation - FMD%). Results In patients, the mean chitotriosidase activity (8.98 ± 6.28) was significantly higher than the controls (5.17 ± 3.42) ( P = 0.014). Chitotriosidase showed positive relation with hs-CRP ( P = 0.011) and SAA ( P = 0.011) but had no relation with ferritin ( P = 0.155), HDL ( P = 0.152) or LDL-cholesterol ( P = 0.380). Mean cIMT increased in patients compared with the controls ( P < 0.001) but did not show any relation with chitotriosidase ( P = 0.546). FMD% decreased in patients ( P < 0.001) also showing no relation with chitotriosidase ( P = 0.298). Ventricular myocardial performance indexes had no significant difference, but RVEF% decreased in patients ( P = 0.043). Conclusions High chitotriosidase activity in common variable immunodeficiency patients demonstrated in vivo the presence of activated macrophages indicating ongoing inflammation. Echocardiographic diastolic functional deficiency, increased cIMT and decreased FMD% may be accepted as early atherosclerotic findings, but none of them showed relationship with chitotriosidase activities.

Chitotriosidase Expression during Monocyte-Derived Dendritic Cells Differentiation and Maturation

The chitotriosidase (CHIT-1) is a glycosyl hydrolase (GH), which has been found highly expressed in activated macrophages and in different monocyte-derived cell lines such as Kupffer cells and osteoclasts, as well is differently produced in diverse stages of macrophage polarization (M1 and M2). Recent finding suggests that CHIT-1 plays a crucial role in innate and acquired immunity. Dendritic cells (DCs) are a complex group of cells that play a critical role in immune response. The aim of this study was to investigate the presence of CHIT-1 during the differentiation and maturation of DCs. Magnetically-isolated peripheral blood monocytes were differentiated toward immature DCs (iDC) and mature DCs (mDCs). Our results showed, for the first time, that CHIT-1 is expressed during the process of differentiation and maturation of DCs in a time-dependent manner. We found that CHIT1 is evenly distributed in cytoplasm of both the iDCs and mDCs. Additionally, a significantly increased expression of CHIT1 mRNA and protein was observed in mature DCs. These results suggest that CHIT-1 play an important role in the DCs immunoresponse.

Elevation of glycoprotein nonmetastatic melanoma protein B in type 1 Gaucher disease patients and mouse models

Gaucher disease is caused by inherited deficiency of lysosomal glucocerebrosidase. Proteome analysis of laser‐dissected splenic Gaucher cells revealed increased amounts of glycoprotein nonmetastatic melanoma protein B (gpNMB). Plasma gpNMB was also elevated, correlating with chitotriosidase and CCL18, which are established markers for human Gaucher cells. In Gaucher mice, gpNMB is also produced by Gaucher cells. Correction of glucocerebrosidase deficiency in mice by gene transfer or pharmacological substrate reduction reverses gpNMB abnormalities. In conclusion, gpNMB acts as a marker for glucosylceramide‐laden macrophages in man and mouse and gpNMB should be considered as candidate biomarker for Gaucher disease in treatment monitoring.

Increased YKL-40 and Chitotriosidase in Asthma and Chronic Obstructive Pulmonary Disease

RATIONALE

Serum chitinases may be novel biomarkers of airway inflammation and remodeling, but less is known about factors regulating their levels.

OBJECTIVES

To examine serum chitotriosidase activity and YKL-40 levels in patients with asthma and chronic obstructive pulmonary disease (COPD) and evaluate clinically relevant factors that may affect chitinase levels, including genetic variability, corticosteroid treatment, disease exacerbations, and allergen exposure.

METHODS

Serum chitotriosidase (CHIT1) activity and YKL-40 (CHI3L1) levels, as well as the CHIT1 rs3831317 and CHI3L1 rs4950928 genotypes, were examined in subsets of patients with mild to moderate asthma (n = 76), severe asthma (n = 93), and COPD (n = 64) taking part in the European multicenter BIOAIR (Longitudinal Assessment of Clinical Course and Biomarkers in Severe Chronic Airway Disease) study. Blood was obtained at baseline, before and after a 2-week oral steroid intervention, up to six times during a 1-year period, and during exacerbations. Baseline chitinase levels were also measured in 72 healthy control subjects. The effect of allergen inhalation on blood and sputum YKL-40 levels was measured in two separate groups of patients with mild atopic asthma; one group underwent repeated low-dose allergen challenge (n = 15), and the other underwent high-dose allergen challenge (n = 16).

MEASUREMENTS AND MAIN RESULTS

Serum chitotriosidase and YKL-40 were significantly elevated in patients with asthma and those with COPD compared with healthy control subjects. Genotype and age strongly affected both YKL-40 and chitotriosidase activity, but associations with disease remained following adjustment for these factors. Correlations were observed with lung function but not with other biomarkers, including exhaled nitric oxide, blood eosinophils, periostin, and IgE. Generally, acute exacerbations, allergen-induced airway obstruction, and corticosteroid treatment did not affect circulating chitinase levels.

CONCLUSIONS

YKL-40 and chitotriosidase are increased in asthma and more so in COPD. The data in the present study support these substances as being relatively steroid-insensitive, non-T-helper cell type 2-type biomarkers distinctly related to chronic inflammatory disease processes.

A complete chitinolytic system in the atherinopsid pike silverside Chirostoma estor: gene expression and activities

The expression and digestive activity of pike silverside Chirostoma estor endogenous chitinases were analysed in samples from four life stages: whole eggs; larvae; juvenile intestine and hepatopancreas and adult intestine and hepatopancreas. A chitinase cDNA was cloned and partially sequenced (GenBank accession number: FJ785521). It was highly homologous to non-acidic chitinase sequences from other fish species, suggesting that it is a chitotriosidase. Quantitative PCR showed that this chitinase was expressed throughout the life span of C. estor, with maximum expression in the hepatopancreas of juveniles. Chitotriosidase and chitobiosidase activities were found at all life stages, along with a very high level of N-acetyl glucosaminidase (NAGase). The chitotriosidase activity could be encoded by the cloned complementary (c)DNA, although additional chitinase genes may be present. The chitotriosidase activity appeared to be transcriptionally regulated only at the juvenile stage. The expression and activity of chitinases tended to increase from the early to juvenile stages, suggesting that these variables are stimulated by chitin-rich live food. Nevertheless, the feeding of juvenile and adult fish with both live food and a balanced commercial diet seemed to provoke significant reductions in pancreatic NAGase secretion and/or synthesis in the gut. Moreover, all chitinase activities were lower in adults, probably reflecting a higher intake and use of the balanced diet. The observation of chitotriosidase and chitobiosidase activities together with a very high NAGase activity suggest the presence of a complete and compensatory chitinolytic chitinase system that enables this stomachless short-gut fish species to use chitin as an energy substrate. These novel findings suggest that dietary inclusions of chitin-rich ingredients or by-products might reduce the farming costs of C. estor without impairing performance.

Chitinase activation in patients with fungus-associated cystic fibrosis lung disease

BACKGROUND

Chitinases have recently gained attention in the field of pulmonary diseases, particularly in asthma and chronic obstructive pulmonary disease, but their potential role in patients with cystic fibrosis (CF)-associated lung disease remains unclear.

OBJECTIVE

The aim of this study was to assess chitinase activity systemically and in the airways of patients with CF and asthma compared with healthy subjects. Additionally, we assessed factors that regulate chitinase activity within the lungs of patients with CF.

METHODS

Chitinase activities were quantified in serum and bronchoalveolar lavage fluid from patients with CF, asthmatic patients, and healthy control subjects. Mechanistically, the role of CF airway proteases and genetic chitinase deficiency was assessed.

RESULTS

Chitinase activity was systemically increased in patients with CF compared with that in healthy control subjects and asthmatic patients. Further stratification showed that chitinase activity was enhanced in patients with CF colonized with Candida albicans compared with that in noncolonized patients. CF proteases degraded chitinases in the airway microenvironment of patients with CF. Genetic chitinase deficiency was associated with C albicans colonization in patients with CF.

CONCLUSION

Patients with CF have enhanced chitinase activation associated with C albicans colonization. Therefore chitinases might represent a novel biomarker and therapeutic target for CF-associated fungal disease.

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.

Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling

Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal-on-metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion-related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri-implant osteolysis. In this study, we characterize tribocorrosion-associated ALTR at a molecular level. Gene expression profiling of peri-implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP-10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT-1). Importantly, MIG/CXCL9 and IP-10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at-risk patients.

Cord blood and consecutive chitotriosidase activity: Relationship to prematurity and early prognosis

BACKGROUND

The aim of this study was to investigate the relationship between plasma chitotriosidase activity, an inflammatory protein secreted mainly from macrophages, and neonatal morbidity and mortality in premature infants.

METHODS

Cord blood chitotriosidase activity was studied in healthy control infants (53 term, group 1; 26 late preterm [33-37 gestational weeks], group 2) and 35 preterm infants (≤ 32 weeks; group 3). In group 3, consecutive samples at 3 h, 24 h, 72 h, 7 days, 14 days, and 36 weeks after conception were also analyzed. Group 3 was also evaluated for mortality, respiratory treatment and bronchopulmonary dysplasia (BPD), patent ductus arteriosus (PDA), intraventricular hemorrhage (IVH) and retinopathy of prematurity (ROP) and necrotizing enterocolitis (NEC).

RESULTS

Cord blood chitotriosidase activity was positively correlated with gestational age and birthweight. SNAPPE-II score was correlated with chitotriosidase activity at 24 h. Consecutive chitotriosidase activity for group 3 was non-significantly higher in infants who died in the early neonatal period. Higher chitotriosidase activity was observed in mechanically ventilated infants than infants treated with non-invasive assisted ventilation. BPD, PDA, IVH and ROP, but not NEC, were related to higher chitotriosidase activity, being significant at some of the time points.

CONCLUSION

Neonatal stress such as invasive ventilation may create a risk for the development of BPD, PDA, IVH, and ROP by increasing macrophage activation in preterm infants as reflected in the higher chitotriosidase activity. High chitotriosidase activity may also be associated with disease severity and mortality.

The effect of nonsurgical periodontal treatment on serum and saliva chitotriosidase activities in patients with periodontitis and coronary artery disease

Background

Plasma chitotriosidase activity, which is a marker of macrophage activation, has been reported to increase in inflammatory conditions and atherosclerosis. Chronic periodontitis has likely an important role in the development of coronary artery disease. In this study, we aimed to analyze the effect of chronic periodontitis on salivary and plasma chitotriosidase activities in patients with or without coronary atherosclerosis.

Methods

Fifty subjects were divided into four groups as controls (n=13), periodontitis (n=11), coronary artery disease (n=13), and periodontitis + coronary artery disease (n=13). Plasma and saliva chitotriosidase activities were measured by a fluorimetric method in all groups before the nonsurgical treatment of periodontitis and 5 weeks posttreatment in periodontitis groups.

Results

Salivary chitotriosidase activity was decreased after nonsurgical periodontal treatment in patients having periodontitis with or without coronary atherosclerosis. However, plasma activities remained unchanged.

Conclusion

Although this study has some limitations like small sample size and short study duration, it can suggest that salivary chitotriosidase can have the potential to be used as a very useful and practical marker to evaluate the success of the periodontal treatment and/or host response.

Key finding

Salivary chitotriosidase can be used as a marker for the evaluation of the success of the periodontal treatment and/or host response.

Proteins from the 18 glycosyl hydrolase family are associated with kidney dysfunction in patients with diabetes type 2

OBJECTIVES

To investigate chitotriosidase (CHIT1) activity and chitinase-3-like protein 1 (YKL-40) concentration in plasma of type 2 diabetic patients and evaluate their relationship with kidney dysfunction.

MATERIALS AND METHODS

94 diabetic subjects and 33 controls were enrolled in the study. Plasma CHIT1 activity and YKL-40 concentration were measured along with routine laboratory parameters.

RESULTS

Levels of CHIT1 and YKL-40 in plasma of type 2 diabetic patients increased progressively with the degree of albuminuria. CHIT1 discriminated normoalbuminuric subjects from those with abnormal albuminuria better than YKL-40.

CONCLUSIONS

CHIT1represent a supportive biomarker connected with development of diabetic vascular complications, especially kidney dysfunction.

Chitotriosidase and lysosomal enzymes as potential biomarkers of disease progression in amyotrophic lateral sclerosis: a survey clinic-based study

The aim of this study was to determine if blood chitotriosidase (Chit) activity and lysosomal enzyme levels might represent markers of disease activity and progression in amyotrophic lateral sclerosis (ALS). It is a survey clinic-based study performed in a tertiary ALS centre. Blood samples were obtained from 76 patients with ALS in different stages of the disease and from 106 healthy individuals serving as controls. Chit activity and the levels of acid alpha-glucosidase, acid alpha-galattosidase A, beta-glucocerebrosidase, and alpha-l-iduronidase were detected using the dried blood spots (DBS) technique. The CHIT1 genotype for exon 10 duplication and for the p.G102S variant was also determined. Chit activity was significantly higher in ALS patients than in healthy individuals. This difference was independent of the genotypes at CHIT1 functional variants. Chit were significantly higher in 34 rapidly progressing patients as compared to 42 with slowly progressive disease. Acid alpha-glucosidase was higher than normal and significantly correlated with the severity of the disease. Glucocerebrosidase and alpha-l-iduronidase activity were significantly lower in patients than in the controls. Alpha-galactosidase A was higher than normal only in rapidly progressing patients. We have employed a very simple and affordable laboratory test to measure blood Chit and lysosomal enzymes activity which could be easily included in the screening of ALS patients recruited in clinical trials. Remarkably, high levels of chitinase and alpha-galactosidase A could help to distinguish patients with fast progression from those with slow progression of the disease and possibly to follow the effects of treatments on neuroinflammation and autophagy.

Implications for diagnosis and therapeutic monitoring

OBJECTIVES

Human plasma chitotriosidase (ChT) activity, a biomarker for evaluating and monitoring Gaucher disease (GD), varies in the general population owing to variants in the CHIT1 gene. Our aim is to determine the frequency of the c.1049_1072dup24 (dup24) and p.G102S polymorphisms, their influence on plasma ChT activity, and its change with enzyme replacement therapy (ERT).

DESIGN AND METHODS

The study included 269 type1 GD patients. Genomic DNA was genotyped using PCR, restriction isotyping and agarose gel electrophoresis. ChT activity was measured with the 4-methylumbelliferyl-β-D-N,N',N″triacetylchitotrioside substrate at non-saturating concentrations at diagnosis, before beginning therapy and after one year on ERT.

RESULTS

Allele frequencies for dup24 and p.G102S were 0.22 and 0.27, respectively. Four percent of patients were homozygous and 37% heterozygous for dup24, and 9% homozygous and 37% heterozygous for p.G102S. The presence of dup24 and p.G102S polymorphisms in the CHIT1 gene significantly reduced plasma ChT activity in naïve patients. By contrast, the percentage of ChT activity decrease after one year of ERT was independent of the presence of these genetic variants.

CONCLUSIONS

This study indicates that genotyping for c.1049_1072dup24 and p.G102S polymorphisms will improve the interpretation of plasma chitotriosidase activity at diagnosis but, this is not mandatory for monitoring of enzyme replacement therapy.

Chitinases: in agriculture and human healthcare

Biological control of phytopathogenic fungi and insects continues to inspire the research and development of environmentally friendly bioactive alternatives. Potentially lytic enzymes, chitinases can act as a biocontrol agent against agriculturally important fungi and insects. The cell wall in fungi and protective covers, i.e. cuticle in insects shares a key structural polymer, chitin, a β-1,4-linked N-acetylglucosamine polymer. Therefore, it is advantageous to develop a common biocontrol agent against both of these groups. As chitin is absent in plants and mammals, targeting its metabolism will signify an eco-friendly strategy for the control of agriculturally important fungi and insects but is innocuous to mammals, plants, beneficial insects and other organisms. In addition, development of chitinase transgenic plant varieties probably holds the most promising method for augmenting agricultural crop protection and productivity, when properly integrated into traditional systems. Recently, human proteins with chitinase activity and chitinase-like proteins were identified and established as biomarkers for human diseases. This review covers the recent advances of chitinases as a biocontrol agent and its various applications including preparation of medically important chitooligosaccharides, bioconversion of chitin as well as in implementing chitinases as diagnostic and prognostic markers for numerous diseases and the prospect of their future utilization.

Identification of seven novel SMPD1 mutations causing Niemann-Pick disease types A and B

Niemann-Pick disease (NPD) types A and B are autosomal, recessively inherited, lysosomal storage disorders caused by deficient activity of acid sphingomyelinase (E.C. 3.1.4.12) because of mutations in the sphingomyelin phosphodiesterase-1 (SMPD1) gene. Here, we present the molecular analysis and clinical characteristics of 15 NPD type A and B patients. Sequencing the SMDP1 gene revealed eight previously described mutations and seven novel mutations including four missense [c.682T>C (p.Cys228Arg), c.1159T>C (p.Cys387Arg), c.1474G>A (p.Gly492Ser), and c.1795C>T (p.Leu599Phe)], one frameshift [c.169delG (p.Ala57Leufs*20)] and two splicing (c.316+1G>T and c.1341delG). The most frequent mutations were p.Arg610del (21%) and p.Gly247Ser (12%). Two patients homozygous for p.Arg610del and initially classified as phenotype B showed different clinical manifestations. Patients homozygous for p.Leu599Phe had phenotype B, and those homozygous for c.1341delG or c.316+1G>T presented phenotype A. The present results provide new insight into genotype/phenotype correlations in NPD and emphasize the difficulty of classifying patients into types A and B, supporting the idea of a continuum between these two classic phenotypes.

The mechanism of the anticancer function of M1 macrophages and their use in the clinic

M1-type macrophages are capable of inducing lysis in various types of cancer cells, but the mechanism of action is unclear. It has been noted that an "unknown protein" produced together with protease by activated macrophages is responsible for this action. Activated M1 macrophages have been recently reported to produce family 18 chitinases, all of which have been named chitotriosidase. Our experiments have demonstrated that family 18 chitinases work together with proteases and can damage various cancer cells both in vitro and in vivo. Thus, in this article, we suggest that the 50-kDa chitotriosidase is the reported "unknown protein". In addition, we discuss how to properly stimulate activated M1 macrophages to produce 50-kDa chitotriosidases and proteases for destroying cancer cells. Because family 19 chitinase has recently been reported to kill cancer cells, we also discuss the possibility of directly using human family 18 chitotriosidase and the humanized plant family 19 chitinase for cancer treatment.

Chitotriosidase gene expression in Kupffer cells from patients with non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Non-alcoholic steatohepatitis (NASH) is a clinicopathological condition characterised by a necroinflammatory disorder with fatty infiltration of the hepatocytes. The molecular mechanisms involved in the anomalous behaviour of liver cells have only partially been determined. Human chitotriosidase (Chit) is a chitinolytic enzyme mainly produced by activated macrophages. The aim of this study was to investigate the expression of the chitinase-like gene in Kupffer cells, to determine how chitotriosidase may be implicated in the progression from uncomplicated steatosis to steatohepatitis with progressive fibrosis.

METHODS

75 subjects were studied: 40 with NASH, 20 with simple steatosis, and 15 normal controls. Kupffer cells obtained from liver biopsies were used to detect CHIT expression, superoxide anion (O2-), lipid peroxidation, and tumour necrosis factor alpha (TNFalpha) and ferritin levels.

RESULTS

CHIT expression differed markedly in livers from normal controls and in those from patients with simple steatosis or non-alcoholic steatohepatitis. A significant correlation between mRNA CHIT and O2-, lipid peroxidation, TNFalpha, and ferritin levels was observed in both NASH and simple steatosis.

CONCLUSIONS

Human Kupffer cells in NASH patients overproduce chitotriosidase. At the highest levels of production, this enzyme may play a role in increasing the risk for a poor outcome in steatohepatitis.