Chitotriosidase in patients with acute ischemic stroke

The chitinases as biomarkers in immune-mediate diseases

The role of chitinases has been focused as potential biomarkers in a wide number of inflammatory diseases, in monitoring active disease state, and predicting prognosis and response to therapies. The main chitinases, CHIT1 and YKL-40, are derived from 18 glycosyl hydrolases macrophage activation and play important roles in defense against chitin-containing pathogens and in food processing. Moreover, chitinases may have organ- as well as cell-specific effects in the context of infectious diseases and inflammatory disorders and able to induce tissue remodelling. The CHIT1 measurement is an easy, reproducible, reliable, and cost-effective affordable assay. The clinical use of CHIT1 for the screening of lysosomal storage disorders is quite practical, when proper cut-off values are determined for each laboratory. The potential of CHIT1 and chitinases has not been fully explored yet and future studies will produce many surprising discoveries in the immunology and allergology fields of research. However, since the presence of a null CHIT1 gene in a subpopulation would be responsible of false-negative values, the assay should be completed with the other markers such ACE and, if necessary, by genetic analysis when CHIT1 is unexpected low.

Biomarkers Predictive of Long-Term Outcome After Ischemic Stroke: A Meta-Analysis

BACKGROUND AND PURPOSE

The goal of this study was to systematically review the utility of serum biomarkers in the setting of ischemic stroke (IS) to predict long-term outcome.

METHODS

A systematic literature review was performed using the PubMed and MEDLINE databases for studies published between 1986-2018. All studies assessing long-term functional outcome (defined as 30 days or greater) following IS with respect to serum biomarkers were included. Data were extracted and pooled using a meta-analysis of odds ratios.

RESULTS

Of the total 2928 articles in the original literature search, 183 studies were ultimately selected. A total of 127 serum biomarkers were included. Biomarkers were grouped into several categories: inflammatory (32), peptide/enzymatic (30), oxidative/metabolic (28), hormone/steroid based (23), and hematologic/vascular (14). The most commonly studied biomarkers in each category were found to be CRP, S100β, albumin, copeptin, and D-dimer. With the exception of S100β, all were found to be statistically associated with >30-day outcome after ischemic stroke.

CONCLUSIONS

Serum-based biomarkers have the potential to predict functional outcome in IS patients. This meta-analysis has identified CRP, albumin, copeptin, and D-dimer to be significantly associated with long-term outcome after IS. These biomarkers have the potential to serve as a platform for prognosticating stroke outcomes after 30 days. These serum biomarkers, some of which are routinely ordered, can be combined with imaging biomarkers and used in artificial intelligence algorithms to provide refined predictive outcomes after injury. Ultimately these tools will assist physicians in providing guidance to families with regards to long-term independence of patients.

Chitinases: Therapeutic Scaffolds for Allergy and Inflammation

Background: Chitinases are the evolutionary conserved glycosidic enzymes that are characterized by their ability to cleave the naturally abundant polysaccharide chitin. The potential role of chitinases has been identified in the manifestation of various allergies and inflammatory diseases. In recent years, chitinases inhibitors are emerging as an alluring area of interest for the researchers and scientists and there is a dire need for the development of potential and safe chitinase antagonists for the prophylaxis and treatment of several diseases.

Objective: The present review expedites the role of chitinases and their inhibitors in inflammation and related disorders.

Methods: At first, an exhaustive survey of literature and various patents available related to chitinases were carried out. Useful information on chitinases and their inhibitor was gathered from the authentic scientific databases namely SCOPUS, EMBASE, PUBMED, GOOGLE SCHOLAR, MEDLINE, EMBASE, EBSCO, WEB OF SCIENCE, etc. This information was further analyzed and compiled up to prepare the framework of the review article. The search strategy was conducted by using queries with key terms “ chitin”, “chitinase”, “chitotrisidase”, “acidic mammalian chitinase”, “chitinase inhibitors”, “asthma” and “chitinases associated inflammatory disorders”, etc. The patents were searched using the key terms “chitinases and uses thereof”, “chitinase inhibitors”, “chitin-chitinase associated pathological disorders” etc. from www.google.com/patents, www.freepatentsonline.com, and www.scopus.com.

Results: The present review provides a vision for apprehending human chitinases and their participation in several diseases. The patents available also signify the extended role and effectiveness of chitinase inhibitors in the prevention and treatment of various diseases viz. asthma, acute and chronic inflammatory diseases, autoimmune diseases, dental diseases, neurologic diseases, metabolic diseases, liver diseases, polycystic ovary syndrome, endometriosis, and cancer. In this regard, extensive pre-clinical and clinical investigations are required to develop some novel, potent and selective drug molecules for the treatment of various inflammatory diseases, allergies and cancers in the foreseeable future.

Conclusion: In conclusion, chitinases can be used as potential biomarkers in prognosis and diagnosis of several inflammatory diseases and allergies and the design of novel chitinase inhibitors may act as key and rational scaffolds in designing some novel therapeutic agents in the treatment of variety of inflammatory diseases.

Targeted mass spectrometry to quantify brain-derived cerebrospinal fluid biomarkers in Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is the most common cause of dementia, characterized by progressive cognitive decline. Protein biomarkers of AD brain pathology, including β-amyloid and Tau, are reflected in cerebrospinal fluid (CSF), yet the identification of additional biomarkers linked to other brain pathophysiologies remains elusive. We recently reported a multiplex tandem-mass tag (TMT) CSF proteomic analysis of nearly 3000 proteins, following depletion of highly abundant proteins and off-line fractionation, across control and AD cases. Of these, over 500 proteins were significantly increased or decreased in AD, including markers reflecting diverse biological functions in brain. Here, we use a targeted mass spectrometry (MS) approach, termed parallel reaction monitoring (PRM), to quantify select CSF biomarkers without pre-depletion or fractionation to assess the reproducibility of our findings and the specificity of changes for AD versus other causes of cognitive impairment.

METHOD

We nominated 41 proteins (94 peptides) from the TMT CSF discovery dataset, representing a variety of brain cell-types and biological functions, for label-free PRM analysis in a replication cohort of 88 individuals that included 20 normal controls, 37 clinically diagnosed AD cases and 31 cases with non-AD cognitive impairment. To control for technical variables, isotopically labeled synthetic heavy peptide standards were added into each of the 88 CSF tryptic digests. Furthermore, a peptide pool, representing an equivalent amount of peptide from all samples, was analyzed (n = 10) across each batch. Together, this approach enabled us to assess both the intra- and inter-sample differences in peptide signal response and retention time.

RESULTS

Despite differences in sample preparation, quantitative MS approaches and patient samples, 25 proteins, including Tau, had a consistent and significant change in AD in both the discovery and replication cohorts. Validated CSF markers with low coefficient of variation included the protein products for neuronal/synaptic (GDA, GAP43, SYN1, BASP1, YWHAB, YWHAZ, UCHL1, STMN1 and MAP1B), glial/inflammation (SMOC1, ITGAM, CHI3L1, SPP1, and CHIT1) and metabolic (PKM, ALDOA and FABP3) related genes. Logistical regression analyses revealed several proteins with high sensitivity and specificity for classifying AD cases from controls and other non-AD dementias. SMOC1, YWHAZ, ALDOA and MAP1B emerged as biomarker candidates that could best discriminate between individuals with AD and non-AD cognitive impairment as well as Tau/β-amyloid ratio. Notably, SMOC1 levels in postmortem brain are highly correlated with AD pathology even in the preclinical stage of disease, indicating that CSF SMOC1 levels reflect underlying brain pathology specific for AD.

CONCLUSION

Collectively these findings highlight the utility of targeted MS approaches to quantify biomarkers associated with AD that could be used for monitoring disease progression, stratifying patients for clinical trials and measuring therapeutic response.

Laboratory diagnosis of the Niemann-Pick type C disease: an inherited neurodegenerative disorder of cholesterol metabolism

Niemann-Pick type C disease (NPC) is a genetically determined neurodegenerative metabolic disease resulting from the mutations in the NPC1 or NPC2 genes. It belongs to the lysosomal storage diseases and its main cause is impaired cholesterol transport in late endosomes or lysosomes. NPC is inherited in an autosomal recessive trait. Due to the wide range in age of onset, often unspecific clinical picture and varying dynamics of disease progression, the diagnosis is very difficult and long-lasting. The most characteristic visceral symptoms are hepato- or hepatosplenomegaly, which may appear independently of neurological or psychiatric symptoms at various stages of the disease. Available biochemical biomarkers should be tested as early as possible in patients presenting with hepato- or hepatosplenomegaly, long-lasting cholestatic jaundice in neonates or infantile patients, as well as in individuals at any age with: vertical supranuclear gaze palsy (VSGP), ataxia, dystonia, frontotemporal dementia and untreatable schizophrenia or psychosis. Research on biomarkers which can detect NPC patients (Cholestan-3β, 5α, 6β-triol, 7-ketocholesterol, lysosphingomyelin isoforms and bile acid metabolites) is still ongoing, although they are not specific for the NPC disease only. This mini review describes currently used diagnostic methods.

Human Chitinases and Chitinase-Like Proteins as Indicators for Inflammation and Cancer

Human Glyco_18 domain-containing proteins constitute a family of chitinases and chitinase-like proteins. Chitotriosidase and AMCase are true enzymes which hydrolyse chitin and have a C-terminal chitin-binding domain. YKL-40, YKL-39, SI-CLP and murine YM1/2 proteins possess solely Glyco_18 domain and do not have the hydrolytic activity. The major sources of Glyco_18 containing proteins are macrophages, neutrophils, epithelial cells, chondrocytes, synovial cells, and cancer cells. Both macrophages and neutrophils use the regulated secretory mechanism for the release of Glyco_18 containing proteins. Glyco_18 containing proteins are established biomarkers for human diseases. Chitotriosidase is overproduced by lipid-laden macrophages and is a major marker for the inherited lysosomal storage Gaucher disease. AMCase and murine lectin YM1 are upregulated in Th2-environment, and enzymatic activity of AMCase contributes to asthma pathogenesis. YKL proteins act as soluble mediators for the cell proliferation and migration, and are also involved in rheumatoid arthritis, inflammatory bowel disease, hepatic fibrosis and cirrhosis. Chitotriosidase and YKL-40 reflect the macrophage activation in atherosclerotic plaques. Serum level of YKL-40 is a diagnostic and prognostic marker for numerous types of solid tumors. YKL-39 is a marker for the activation of chondrocytes and the progression of the osteoarthritis in human. Recently identified SI-CLP is upregulated by Th2 cytokine IL-4 as well as by glucocorticoids. This unique feature of SI-CLP makes it an attractive candidate for the examination of individual sensitivity of patients to glucocorticoid treatment and prediction of side effects of glucocorticoid therapy. Human chitinases and chitinase-like proteins are found in tissues and circulation, and can be detected by non-invasive technologies.

Proteomic studies in the discovery of cerebrospinal fluid biomarkers for amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a progressive degenerative motor neuron disease, which usually leads to death within a few years. The diagnosis is mainly based on clinical symptoms and there is a need for ALS-specific biomarkers to make an early and precise diagnosis, for development of disease-modifying drugs and to gain new insights into pathophysiology. Areas covered: In the present review, we summarize studies using mass spectrometric (MS) approaches to identify protein alterations in the cerebrospinal fluid (CSF) of ALS patients. In total, we identified 11 studies fulfilling our criteria by searching in the PubMed database using the keywords 'ALS' and 'CSF' combined with 'proteome', 'proteomic', 'mass spectrometry' or 'protein biomarker'. Ten proteins were differently regulated in ALS CSF compared to controls in at least 2 studies. We will discuss the relevance of the identified proteins regarding the frequency of identification, extent of alteration and brain-specificity. Expert commentary: Most of the identified CSF biomarker candidates are irreproducible or mainly blood-derived. We assign the missing success of CSF proteomic studies in biomarker discovery to a lack of sensitivity, unsuitable normalization, low quality assurance and variations originating from sample preparation. These issues must be improved in future proteomic studies in CSF.

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.

Assessment of a multiple biomarker panel for diagnosis of amyotrophic lateral sclerosis

Background

The aim of the study was to assess a panel of promising biomarkers for their ability to improve diagnosis of sporadic amyotrophic lateral sclerosis (ALS).

Methods

Forty patients with sporadic ALS and 40 controls with other neurological diseases were evaluated. Levels of phosphorylated neurofilament heavy chain (pNfH), S100-β, cystatin C, and chitotriosidase (CHIT) in cerebrospinal fluid were assayed using two-site solid-phase sandwich ELISA.

Results

Patients with sporadic ALS showed higher levels of pNfH and CHIT than controls, but lower levels of cystatin C. Multivariate logistic regression that adjusted for patient age and sex identified significant associations between sporadic ALS and levels of pNfH, CHIT and cystatin C. Levels of pNfH correlated positively with rate of progression and decline based on the Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised. Based on receiver operating curve analysis, a pNfH cut-off of 437 ng/L discriminated patients from controls with a sensitivity of 97.3 % and specificity of 83.8 %. A CHIT cut-off of 1593.779 ng/L discriminated patients from controls with a sensitivity of 83.8 % and specificity of 81.1 %. Combining the two biomarkers gave a sensitivity of 83.8 % and specificity of 91.9 %.

Conclusions

Levels of pNfH in cerebrospinal fluid may be a reliable biomarker for diagnosing ALS, and combining this biomarker with levels of CHIT may improve diagnostic accuracy.

Diagnostic tests for Niemann-Pick disease type C (NP-C): A critical review

Niemann-Pick disease type C (NP-C) is a neurovisceral lysosomal cholesterol trafficking and lipid storage disorder caused by mutations in one of the two genes, NPC1 or NPC2. Diagnosis has often been a difficult task, due to the wide range in age of onset of NP-C and clinical presentation of the disease, combined with the complexity of the cell biology (filipin) laboratory testing, even in combination with genetic testing. This has led to substantial delays in diagnosis, largely depending on the access to specialist centres and the level of knowledge about NP-C of the physician in the area. In recent years, advances in mass spectrometry has allowed identification of several sensitive plasma biomarkers elevated in NP-C (e.g. cholestane-3β,5α,6β-triol, lysosphingomyelin isoforms and bile acid metabolites), which, together with the concomitant progress in molecular genetic technology, have greatly impacted the strategy of laboratory testing. Specificity of the biomarkers is currently under investigation and other pathologies are being found to also result in elevations. Molecular genetic testing also has its limitations, notably with unidentified mutations and the classification of new variants. This review is intended to increase awareness on the currently available approaches to laboratory diagnosis of NP-C, to provide an up to date, comprehensive and critical evaluation of the various techniques (cell biology, biochemical biomarkers and molecular genetics), and to briefly discuss ongoing/future developments. The use of current tests in proper combination enables a rapid and correct diagnosis in a large majority of cases. However, even with recent progress, definitive diagnosis remains challenging in some patients, for whom combined genetic/biochemical/cytochemical markers do not provide a clear answer. Expertise and reference laboratories thus remain essential, and further work is still required to fulfill unmet needs.

Chitotriosidase: A New Inflammatory Marker in Diabetic Complications

Chitotriosidase (CHIT1) belongs to chitinase family. So far this enzyme has been the best investigated human chitinase regarding its biological activity and association with various disorders. In a healthy population, CHIT1 activity is very low and originates in the circulating polymorphonuclear cells. Conversely, during the development of acute/chronic inflammatory disorders, the enzymatic activity of CHIT1 increases significantly. Recently, CHIT1 has also been involved in the pathogenesis of diabetes mellitus (DM). Mounting evidence from experimental studies revealing the increase of CHIT1 levels in pathological conditions, such as atherosclerosis, coronary artery disease, acute ischemic stroke, cerebrovascular dementia, nonalcoholic fatty liver disease, and osteolytic processes suggest its critical role in the evolutions and complications of DM. This review is addressed to provide mechanistic insights by highlighting the relationship between CHIT1 and diabetes, and their contribution in the exacerbation of this 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.

Characterization of traumatic brain injury in human brains reveals distinct cellular and molecular changes in contusion and pericontusion

Traumatic brain injury (TBI) contributes to fatalities and neurological disabilities worldwide. While primary injury causes immediate damage, secondary events contribute to long-term neurological defects. Contusions (Ct) are primary injuries correlated with poor clinical prognosis, and can expand leading to delayed neurological deterioration. Pericontusion (PC) (penumbra), the region surrounding Ct, can also expand with edema, increased intracranial pressure, ischemia, and poor clinical outcome. Analysis of Ct and PC can therefore assist in understanding the pathobiology of TBI and its management. This study on human TBI brains noted extensive neuronal, astroglial and inflammatory changes, alterations in mitochondrial, synaptic and oxidative markers, and associated proteomic profile, with distinct differences in Ct and PC. While Ct displayed petechial hemorrhages, thrombosis, inflammation, neuronal pyknosis, and astrogliosis, PC revealed edema, vacuolation of neuropil, axonal loss, and dystrophic changes. Proteomic analysis demonstrated altered immune response, synaptic, and mitochondrial dysfunction, among others, in Ct, while PC displayed altered regulation of neurogenesis and cytoskeletal architecture, among others. TBI brains displayed oxidative damage, glutathione depletion, mitochondrial dysfunction, and loss of synaptic proteins, with these changes being more profound in Ct. We suggest that analysis of markers specific to Ct and PC may be valuable in the evaluation of TBI pathobiology and therapeutics. We have characterized the primary injury in human traumatic brain injury (TBI). Contusions (Ct) - the injury core displayed hemorrhages, inflammation, and astrogliosis, while the surrounding pericontusion (PC) revealed edema, vacuolation, microglial activation, axonal loss, and dystrophy. Proteomic analysis demonstrated altered immune response, synaptic and mitochondrial dysfunction in Ct, and altered regulation of neurogenesis and cytoskeletal architecture in PC. Ct displayed more oxidative damage, mitochondrial, and synaptic dysfunction compared to PC.

Chitotriosidase - a putative biomarker for sporadic amyotrophic lateral sclerosis

Background

Potential biomarkers to aid diagnosis and therapy need to be identified for Amyotrophic Lateral Sclerosis, a progressive motor neuronal degenerative disorder. The present study was designed to identify the factor(s) which are differentially expressed in the cerebrospinal fluid (CSF) of patients with sporadic amyotrophic lateral sclerosis (SALS; ALS-CSF), and could be associated with the pathogenesis of this disease.

Results

Quantitative mass spectrometry of ALS-CSF and control-CSF (from orthopaedic surgical patients undergoing spinal anaesthesia) samples showed upregulation of 31 proteins in the ALS-CSF, amongst which a ten-fold increase in the levels of chitotriosidase-1 (CHIT-1) was seen compared to the controls. A seventeen-fold increase in the CHIT-1 levels was detected by ELISA, while a ten-fold elevated enzyme activity was also observed. Both these results confirmed the finding of LC-MS/MS. CHIT-1 was found to be expressed by the Iba-1 immunopositive microglia.

Conclusion

Elevated CHIT-1 levels in the ALS-CSF suggest a definitive role for the enzyme in the disease pathogenesis. Its synthesis and release from microglia into the CSF may be an aligned event of neurodegeneration. Thus, high levels of CHIT-1 signify enhanced microglial activity which may exacerbate the process of neurodegeneration. In view of the multifold increase observed in ALS-CSF, it can serve as a potential CSF biomarker for the diagnosis of SALS.

Prognostic Value of Plasma Chitotriosidase Activity in Acute Stroke Patients

Background and aims

Chitotriosidase, a component of innate immunity, constitutes a sensitive parameter of macrophage activation and its elevated plasma activity reflects an inflammatory response. Given the deleterious effects of inflammation in brain ischemia, we aimed to assess the prognostic value of chitotriosidase activity in acute stroke patients.

Methods

The study comprised 159 acute stroke patients and 51 age-matched controls. Plasma chitotriosidase activity was serially determined by fluorometric assay. Short-term neurological outcome was determined at 48 h and functional outcome at three-months. Predictors of neurological and functional outcome were determined via multivariate analysis, and the additional predictive value of chitotriosidase was tested with the Integrated Discrimination Index and the Net Reclassification Improvement.

Results

Stroke patients showed increased levels of baseline chitotriosidase activity compared to controls [114·2 (74·65–182·95) nmol/ml/h vs. 54·4 (32·7–76·4); P < 0·0001]. Chitotriosidase activity (<118·75) was found to be an independent predictor of neurological improvement at 48 h (odds ratio: 3·25; 95% confidence interval: 1·54–6·85; P = 0·002), and the addition of plasma chitotriosidase activity showed a better prediction of improvement at 48 h (Integrated Discrimination Index = 5·7%, Net Reclassification Improvement = 11·6%, P < 0·05) over the predictive model constituted only with clinical information. Although patients disabled at three-months showed higher baseline chitotriosidase levels, it was not an independent predictor of long-term disability.

Conclusions

Baseline chitotriosidase activity in acute stroke patients treated with tissue plasminogen activator (tPA) may constitute a prognostic predictor of short-term outcome, adding a moderate additional predictive value. Our results underline the deleterious role of inflammation in acute stroke patients.

Role of SH levels and markers of immune response in the stroke

Background. Sulfhydryl groups (SH) are considered a key factor in redox sensitive reaction of plasma, and their modification could be considered an expression of abnormal generation of oxygen free radicals. Methods. Fifty consecutive patients with acute brain stroke were enclosed in this study. The plasma concentrations of SH groups were correlated to cytokines (IL-1b, IL-6, IL-8, TNF-α), plasma chitotriosidase (Chit), metalloprotease (MMP2–9), intercellular adhesion molecule-1 (ICAM-1). Results. The results demonstrated a significant reduction of SH groups within 24 hours from the onset of an acute ischemic stroke, a reduction of plasma IL-1b, IL-6, and IL-8, and an increase of Chit and TNF-α in relation to the stroke severity. Conclusion. The observation of an intense microenvironment activation that follows the stroke and the correlation between SH levels and markers of immune response suggest that, especially in stroke, is necessary to maintain the redox function to prevent the brain damage. The reduced SH levels represent an attempt to neutralize the abnormal generation of free radicals. Since the reperfusion of brain after ischemic event represents a severe oxidative stress, which must be corrected by regeneration of redox sensitive function, pharmacological intervention could be beneficial in this setting.

Chitinase inhibition promotes atherosclerosis in hyperlipidemic mice

Chitinase 1 (CHIT1) is secreted by activated macrophages. Chitinase activity is raised in atherosclerotic patient sera and is present in atherosclerotic plaque. However, the role of CHIT1 in atherosclerosis is unknown. Preliminary studies of atherosclerosis in cynomolgous monkeys revealed CHIT1 to be closely correlated with areas of macrophage infiltration. Thus, we investigated the effects of a chitinase inhibitor, allosamidin, on macrophage function in vitro and on atherosclerotic development in vivo. In RAW264.7 cells, allosamidin elevated monocyte chemoattractant protein 1 and tumor necrosis factor alpha expression, and increased activator protein 1 and nuclear factor-κB transcriptional activity. Although inducible nitric oxide synthase, IL-6, and IL-1β expression were increased, Arg1 expression was decreased by chitinase inhibition, suggesting that suppression of CHIT1 activity polarizes macrophages into a M1 phenotype. Allosamidin decreased scavenger receptor AI, CD36, ABCA1, and ABCG1 expression which led to suppression of cholesterol uptake and apolipoprotein AI-mediated cholesterol efflux in macrophages. These effects were confirmed with CHIT1 siRNA transfection and CHIT1 plasmid transfection experiments in primary macrophages. Apolipoprotein E-deficient hyperlipidemic mice treated for 6 weeks with constant administration of allosamidin and fed an atherogenic diet showed aggravated atherosclerotic lesion formation. These data suggest that CHIT1 exerts protective effects against atherosclerosis by suppressing inflammatory responses and polarizing macrophages toward an M2 phenotype, and promoting lipid uptake and cholesterol efflux in macrophages.

Minocycline prevents IL-6 increase after acute ischemic stroke

Higher levels of the inflammatory biomarker interleukin-6 (IL-6) correlate with poor clinical outcome in acute ischemic stroke (AIS). Minocycline (MC) is a known anti-inflammatory agent; thus, the effect of MC on IL-6 in the first 24 h of AIS was investigated to determine potential anti-inflammatory activity. The Minocycline to Improve Neurologic Outcome in Stroke (MINOS) study was a non-randomized dose-escalation (3.0-10.0 mg/kg) trial of IV MC for AIS within 6 h of onset. Plasma IL-6 samples were collected prior to MC treatment at 1, 24, and 72 h and compared to those collected in a separate observational study of blood biomarkers in AIS. IL-6 levels were measured by commercially available ELISA kits. The lower limit of detection for IL-6 was 1 pg/ml. Sixty MINOS subjects and 29 non-MINOS subjects were enrolled, and there was no difference in baseline stroke severity. There was no significant difference in IL-6 level pre-MC treatment at 1, 24, or 72 h. However, the odds of a non-detectable IL-6 at 24 h in MINOS were 8.94 (95% CI 2.62-30.46) compared with non-MINOS subjects. It is likely that even low doses of MC have a potent systemic anti-inflammatory effect in AIS. Whether this results in improved outcome will be tested in a randomized clinical trial.

Chitotriosidase as a biomarker of cerebral adrenoleukodystrophy

Background

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

Methods

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

Results

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

Conclusions

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

Plasma chitotriosidase activity in children with lysosomal storage disorders

Chitotriosidase (ChT) is an enzyme that is selectively activated in tissue macrophage. This property of ChT makes it a potential marker for many disease process and prognostication. Present study has been carried out to know the significance of ChT as a screening marker in lysosomal storage disorders (LSDs) where tissue macrophage activation is commonly observed due to accumulation of substrate in various organs of the body. Study comprises of 20 healthy children in the age range of 10 days to 5 yrs and 56 children in the age range of 2.5 months to 13 yrs with regression of milestones, skeletal dysplasia, neuroregression and hepatosplenomegaly were selected for plasma ChT who had confirmed LSDs as carried out by specific lysosomal enzyme study from the leukocytes or fibroblasts. Plasma ChT was 55.21 +/- 20.81 nmol/ml/hr in twenty healthy age matched controls. Plasma ChT level was 42.88 to 79.78 nmol/ml/hr in thirteen of 56 (23.21%) children with LSDs like Morquio-B, Pompe, Metachromatic leucodystrophy (MLD), Sandhoff and Niemann-Pick disease type C (NPD-C). While in 43 (76.78%) children it was in the range of 213.74 to 23,511.40 nmol/ml/hr. who had LSDs like Morquio-B, Sly syndrome, MLD, GM2 Gangliosidosis, NPD-A/B and Gaucher disease (GD). Marked elevated ChT (4,000 to 23,511 nmol/ml/hr) was observed in all cases of GD (n=7) and NDP-A/B. It can be concluded from the present study that moderately raised activity of ChT can be utilized as a positive predictive test for certain LSD's. Those with marked elevated ChT have confirmed GD or NPD-A/B making it a strong screening marker for this group of diseases.

Human chitotriosidase polymorphism is associated with human longevity in Mediterranean nonagenarians and centenarians

Human phagocyte-specific chitotriosidase (CHIT-1) is a chitinolytic enzyme associated with several diseases involving macrophage activation. Previous studies have demonstrated that a high activity of Chit could have widespread effects on atherosclerosis, cardiovascular disease and dementia. The 24-bp duplication in the CHIT-1 gene is associated with a deficiency in enzymatic activity. In this study, we attempted to assess whether CHIT-1 could be a plausible candidate gene responsible for human longevity. Therefore, we compared the distribution of the CHIT-1 polymorphism genotype in three different populations of the Mediterranean area (Italian, Greek and Tunisian) aged over 90 years. As a control group for each nonagenarian and centenarian, a 60-70-year-old subject was genotyped. We found that the heterozygote frequency for the 24-bp duplication in the CHIT-1 gene was not significantly different among the oldest old subjects of Mediterranean populations, whereas it was significantly different between oldest old subjects and control subjects, being highest among the oldest old subjects and lowest among control groups. In the oldest old group, no subject was observed to be homozygous for CHIT-1 deficiency. Moreover, the mean enzymatic activity in heterozygous oldest subjects was lower than that in the control group. These data indicate that the heterozygosis for a 24-bp duplication in the CHIT-1 gene could have a protective effect in human longevity.

Molecular biomarkers in stroke diagnosis and prognosis

Serum biomarkers related to the cascade of inflammatory, hemostatic, glial and neuronal perturbations have been identifed to diagnose and characterize intracerebral hemorrhage and cerebral ischemia. Interpretation of most markers is confounded by their latent rise, blood-brain barrier effects, the heterogeneity of etiologies and the wide range of normal values, limiting their application for early diagnosis, lesion size estimation and long-term outcome prediction. Certain hemostatic and inflammatory constituents have been found to predict response to thrombolysis and worsening due to infarct progression and secondary hemorrhage, offering a potential role for improved treatment selection and individualization of therapy. Biomarkers will become increasingly relevant for developing targets for neuroprotective therapies, monitoring response to treatment and as surrogate end points for treatment trials.

The promise and potential pitfalls of serum biomarkers for ischemic stroke and transient ischemic attack

BACKGROUND

Ischemic stroke and transient ischemic attack can be difficult to diagnose clinically, and both acute and preventive therapies carry some risk. Serum biomarkers could increase diagnostic certainty by helping to distinguish cerebral ischemia from common mimics such as focal seizure, complicated migraine, and psychogenic spells. Biomarkers could also identify patients at high risk for future vascular events, which would aid in management decisions.

REVIEW SUMMARY

There are many potential obstacles to finding these biomarkers, which are reviewed here, including the blood brain barrier, confounding by other conditions, and imperfect gold standards for use in validation. Diagnostic biomarkers are likely to be molecules found predominantly in brain tissue with rapid entry into the blood, whereas risk-stratification biomarkers may be related to the concept of an active atherosclerotic plaque. Many promising serum molecules have been examined in small series of patients with cerebrovascular disease.

CONCLUSION

Large series examining many candidate molecules will be needed to find valid biomarkers, and this should be followed by use in future intervention trials to prove their utility.

The application of proteomics technology to thrombosis research: the identification of potential therapeutic targets in cardiovascular disease

Thrombus formation underpins the development of cardiovascular diseases, including acute coronary syndromes and ischaemic stroke. A number of well-characterised cardiovascular risk factors which contribute to the development of the majority of cardiovascular events have been identified, including dyslipidaemia, hypertension and diabetes. Individuals with type 2 diabetes mellitus (T2DM) have a 3- to 5-fold increased risk for development of cardiovascular disease (CVD). They may have a cluster of haemostatic abnormalities, including elevated levels of plasminogen activator inhibitor-1 (PAI-1) and fibrinogen, which contribute to acute thrombotic events. It is clear that additional unidentified risk factors contribute to the pathogenesis of cardiovascular events, and so the search for novel biomarkers and effectors, particularly in individuals with T2DM, remains a major challenge of cardiovascular medicine. Plasma and cellular proteins which contribute to thrombus formation have the potential to confer a pro-thrombotic state and represent a link between genotype, environment and disease phenotype. The comprehensive analysis of these proteins is now increasingly facilitated through the continued development of proteomic technologies which provide multifaceted approaches to the identification of novel biomarkers and/or effectors of thrombus formation and on which future anticoagulant and thrombolytic therapies may be based. This review provides an overview of current proteomic technologies. It focuses on the recent studies in which these technologies have been applied in the search for novel proteins that may confer increased risk of acute cardiovascular diseases and therefore that may influence disease progression and therapy.

Different content of chitin-like polysaccharides in multiple sclerosis and Alzheimer's disease brains

Chitin is an insoluble N-acetyl-glucosamine polymer coating fungi cell wall and several human parasites. It is hydrolysed by chitotriosidase (Chit); however, as chitin is absent in humans, the significance of human Chit activity is unknown. The level of plasma Chit activity positively correlates with Alzheimer's disease (AD) and multiple sclerosis (MS). A recent study revealed the presence of potentially detrimental chitin-like substances in AD brain by Calcofluor histochemistry, whilst its search in MS brains has never been described to date. Through a comparative immunohistochemical analysis we confirm the presence of abundant chitin-like deposition in AD brains but fail to demonstrate it in MS brains. Interestingly, co-localization of beta-amyloid, Calcofluor and the nuclear marker DAPI was observed. Therefore, Chit production in MS patients is induced by mechanisms other than those operating in AD. Microglia-derived Chit activity in MS may counterbalance the naturally occurring glucosamine aggregation, protecting the brain from the chitin-like substance deposition.

Increased serum chitotriosidase activity following restoration of euthyroidism in patients with subclinical hypothyroidism

OBJECTIVE

Whether to treat subclinical hypothyroidism (SH) remains controversial. Serum chitotriosidase activity, a marker of activated macrophages, predicts new cardiovascular events. Chitotriosidase activity (ChT) is a new cardiovascular risk marker and is independent of C-reactive protein. The purpose of this study was to determine ChT levels in SH and to examine the effect of levothyroxine replacement on ChT.

SUBJECTS AND METHODS

A cohort of 60 patients with subclinical hypothyroidism and 62 healthy controls were enrolled in this study. Serum total and LDL cholesterol, total homocysteine (t-Hyc), highly sensitive C-reactive protein (hsCRP) levels and serum ChT in patients with subclinical hypothyroidism at baseline and after achieving euthyroid state by levothyroxine were assessed.

RESULTS

Pretreatment levels of TSH (10.06+/-5.09 vs. 2.08+/-0.95 mIU/L, p<0.05), and free T4 (0.94+/-0.21 vs. 1.35+/-0.26 ng/dl, p<0.05) were significantly higher than controls while total cholesterol, LDL cholesterol, t-Hyc, ChT and hsCRP levels were not different. ChT levels significantly increased after replacement therapy (137.2+/-14.18 vs. 156.88+/-13.10 nmol/mL/h, p<0.05). T-Hyc and hsCRP levels were not significantly different after treatment with levothyroxine therapy even in this subgroup of patients. None of the other biochemical risk factors improved after euthyroidism in patients with SH with average dose of 85+/-30 mug/day when compared to pretreatment levels.

CONCLUSION

We conclude that clinical management of subclinical hypothyroidism does not decrease the serum hsCRP or t-Hyc levels but does increase the serum ChT levels. The clinical significance of this increment should be studied in further studies.

Chitotriosidase activity in the serum of patients with sarcoidosis and pulmonary tuberculosis

BACKGROUND

Human chitotriosidase is a chitinase selectively expressed by activated macrophages. An increase in chitotriosidase activity was previously described by us in the serum and bronchoalveolar lavage of sarcoidosis patients.

OBJECTIVE

The aim of the present study was to analyze serum chitotriosidase activity in a larger number of sarcoidosis patients to verify the reported increase with respect to controls and to compare serum chitotriosidase levels in patients with sarcoidosis and tuberculosis, two granulomatous disorders of different etiology.

METHODS

Chitotriosidase activity was measured in the serum of 96 sarcoidosis patients, 15 pulmonary tuberculosis patients and 30 healthy controls.

RESULTS

We found significantly higher serum chitotriosidase activity in sarcoidosis patients than controls (p < 0.01) and in sarcoidosis patients than tuberculosis patients (p < 0.01), confirming a striking elevation of chitotriosidase activity (>10 times greater than normal) in pulmonary sarcoidosis patients. This is the first time that chitotriosidase activity has been analyzed in the serum of patients with pulmonary tuberculosis; it was found to be significantly lower than in sarcoidosis patients and not significantly greater than in controls.

CONCLUSION

Although the mechanisms leading to the increase in chitotriosidase activity in sarcoidosis are still unknown, this enzyme may be specifically involved in the pathogenesis of the disease. Further studies with a greater number of patients are needed to confirm these results and to determine whether chitotriosidase could be a marker with diagnostic or prognostic value in sarcoidosis.

Comparison between the biochemical properties of plasma chitotriosidase from normal individuals and from patients with Gaucher disease, GM1-gangliosidosis, Krabbe disease and heterozygotes for Gaucher disease

OBJECTIVES

The aim of the present work was to establish the range of chitotriosidase (CT) activity in normal individuals (controls), patients with Gaucher disease (GD), GM1-gangliosidosis (GM1), Krabbe disease (KD) and heterozygotes for Gaucher disease (HG). The kinetics of the enzyme in the five groups was also investigated.

DESIGN AND METHODS

Plasma CT activity, as well as Km, Vmax, optimum pH and thermal stability of the enzyme was determined in plasma of controls, GM1, KD, GD and HG subjects.

RESULTS

CT activity in GD, GM1 and KD patients was, respectively, around 600-fold, 15-fold and 12-fold greater than in normal individuals. There was no significant difference between CT activity in the HG and the control group. We also demonstrated that all CT kinetic parameters evaluated (optimum pH, Km, Vmax, thermal stability) in plasma of GD, KD and GM1 patients were significantly different from those of normal individuals. Regarding to thermal stability, our results show that CT activity in the control group was more stable than in the other groups.

CONCLUSIONS

Based on the differences found in the biochemical parameters studied, we presume that the parameters analyzed may be useful in the diagnosis of the Lysosomal Storage Diseases.