Chitotriosidase activity predicts endothelial dysfunction in type-2 diabetes mellitus

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.

Circulating 18-Glycosyl Hydrolase Protein Chitiotriosidase-1 is Associated with Renal Dysfunction and Systemic Inflammation in Diabetic Kidney Disease

Introduction

Chitotriosidase-1 (CHIT-1) is a marker of macrophage activation and recently attributed to type 2 diabetes mellitus (T2DM). However, its role in the development and progression of diabetic kidney disease (DKD) has been sparsely discussed in the recent literature.

Materials and Methods

In this cross-sectional exploratory study, 81 participants with T2DM were classified into two groups based on the presence of DKD. Their anthropometric, biochemical, and pathological profiles were estimated. Circulatory CHIT-1 concentration was determined using the enzyme-linked immuno-sorbent assay (ELISA) in plasma.

Results

CHIT-1 was significantly elevated in diabetic nephropathy, independent of age and gender. It is associated with severity of kidney disease, as assessed using urinary protein-creatinine ratio (uPCR) in a multiple linear regression model, independent of age, gender, diabetes duration, and insulin resistance. CHIT-1 positively predicted the likelihood of DKD in the study population (area under the curve = 0.724, P < 0.05). The duration of diabetes correlated positively with uPCR and negatively with estimated glomerular-filtration rate. Neutrophil-Lymphocyte ratio was elevated in participants with DKD. This well-established marker of systemic inflammation exhibited significant positive association with CHIT-1.

Conclusion

Plasma CHIT-1 protein is elevated in DKD and associated with disease progression. It is capable of reflecting disease severity and is closely related to systemic inflammation possibly caused by pro-inflammatory circulatory immune cells.

Irreversible evolutionary loss of chitin-degrading ability in the chitinase-like protein Ym1 under positive selection in rodents

Ym1 (chitinase-like 3, Chil3) expressed in mice is a nonenzymatic chitinase-like protein, which shows 67% identity with mouse acidic chitinase (Chia). Similar to Chia, Ym1 is overexpressed in asthma and parasitic infections in mouse lungs. Due to the lack of chitin-degrading activity, the biomedical role of Ym1 under these pathophysiological conditions remains to be determined. In this study, we investigated what region and amino acid changes in Ym1 resulted in the loss of enzymatic activity. Replacing two amino acids at the catalytic motif to obtain a Chia-like sequence (N136D and Q140E; MT-Ym1) did not activate the protein. We conducted a comparative study of Ym1 and Chia. We found that three protein segments-(i) the catalytic motif residues, (ii) exons 6 and 7, and (iii) exon 10-are responsible for chitinase activity loss in Ym1. We show that replacing each of these three segments in Chia that are also involved in substrate recognition and binding by the Ym1 sequence can fully abolish the enzymatic activity. In addition, we show that there have been extensive gene duplication events at the Ym1 locus specific to the rodent lineages. Consistent with this result, Ym1 orthologs from the rodent genome were under positive selection when analyzed through the CODEML program. These data suggest that numerous amino acid substitutions in the regions involved in the chitin recognition, binding, and degradation ability of the ancestor Ym1 molecule lead to the irreversible inactivation of the protein.

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.

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.

The changing features of serum adropin, copeptin, neprilysin and chitotriosidase which are associated with vascular endothelial function in type 2 diabetic retinopathy patients

AIMS

Adropin (AD), copeptin (CP), neprilysin (NEP) and chitotriosidase (CHIT1) have been associated with the regulation of vascular endothelial function. In this work, we analyzed the plasma concentrations of cytokines (AD, CP, NEP and CHIT1) in type 2 diabetic patients with or without retinopathy (DR) to predict the risk of DR for diabetic patients.

METHOD

A total of 392 patients diagnosed as type 2 diabetes mellitus (T2DM) and 120 healthy volunteers as a control group were enrolled in this study. T2DM patients were divided into three groups: diabetes without retinopathy (NDR, n = 174) group, non-proliferative diabetic retinopathy (NPDR, n = 118) group and proliferative diabetic retinopathy (PDR, n = 100) group. The serum AD, CP, NEP and CHIT1 levels of subjects were detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We reported a significant decrease in AD and a significant increase in CP, NEP and CHIT1 in NDR as well as DR patients when compared with controls (p < 0.05), the lower level of AD and significantly higher levels of CP, NEP and CHIT1 were seen in DR patients compared to NDR group (p < 0.05), at the same time, we observed the lowest level of AD and the highest levels of CP, NEP and CHIT1 in the PDR group. Logistic regression analysis showed that AD was a protective factor for DR, conversely, CP, NEP and CHIT1 were the independent risk factors (p < 0.05). Moreover, receiver operating characteristic curve analyses indicated that CP had greater diagnosis capacity with an AUC (the areas under the ROC curve) of 0.901 than AD, NEP, CHIT1 for DR patients.

CONCLUSION

The decreased AD level and the elevated CP, NEP and CHIT1 levels involved in vascular endothelial function may be evidence facilitating the presence of DR. Thereby they can be explored to use as promising non-invasive biomarkers for prediction of DR severity, distinguishing DR from diabetic patients.

Comparative functional analysis between human and mouse chitotriosidase: Substitution at amino acid 218 modulates the chitinolytic and transglycosylation activity

Chitotriosidase (Chit1) and acidic mammalian chitinase (AMCase) have been attracting research interest due to their involvement in various pathological conditions such as Gaucher's disease and asthma, respectively. Both enzymes are highly expressed in mice, while the level of AMCase mRNA was low in human tissues. In addition, the chitinolytic activity of the recombinant human AMCase was significantly lower than that of the mouse counterpart. Here, we revealed a substantially higher chitinolytic and transglycosylation activity of human Chit1 against artificial and natural chitin substrates as compared to the mouse enzyme. We found that the substitution of leucine (L) by tryptophan (W) at position 218 markedly reduced both activities in human Chit1. Conversely, the L218W substitution in mouse Chit1 increased the activity of the enzyme. These results suggest that Chit1 may compensate for the low of AMCase activity in humans, while in mice, highly active AMCase may supplements low Chit1 activity.

Tape-Strip Proteomic Profiling of Atopic Dermatitis on Dupilumab Identifies Minimally Invasive Biomarkers

Tape-stripping is a minimally invasive approach for skin sampling that captures the cutaneous immune/barrier abnormalities in atopic dermatitis (AD). However, tape-strips have not been used to evaluate molecular changes with therapeutic targeting. In this study, we sought to characterize the proteomic signature of tape-strips from AD patients, before and after dupilumab therapy. Twenty-six AD patients were treated with every-other-week dupilumab 300 mg for 16 weeks. Tape-strips from lesional and non-lesional skin were collected before and after treatment, and analyzed with the Olink proteomic assay. Using criteria of fold-change>1.5 and FDR < 0.05, 136 proteins significantly decreased after dupilumab treatment, corresponding to an overall mean improvement of 66.2% in the lesional vs. non-lesional AD proteome. Significant decreases after dupilumab were observed in immune markers related to general inflammation (MMP12), Th2 (CCL13/CCL17), Th17/Th22 (IL-12B, CXCL1, S100A12), and innate immunity (IL-6, IL-8, IL-17C), while the Th1 chemokines CXCL9/CXCL10 remained elevated. Proteins related to atherosclerosis/cardiovascular risk (e.g., SELE/E-selectin, IGFBP7, CHIT1/ chitotriosidase-1, AXL) also significantly decreased after treatment. Dupilumab therapy suppressed AD-related immune biomarkers and atherosclerosis/cardiovascular risk proteins. Tape-strip proteomics may be useful for monitoring therapeutic response in real-life settings, clinical trials, and longitudinal studies for AD and beyond.

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.

Chitin digestibility is dependent on feeding behaviors, which determine acidic chitinase mRNA levels in mammalian and poultry stomachs

Chitin, a polymer of N-acetyl-D-glucosamine (GlcNAc), functions as a major structural component in chitin-containing organism including crustaceans, insects and fungi. Recently, we reported that acidic chitinase (Chia) is highly expressed in mouse, chicken and pig stomach tissues and that it can digest chitin in the respective gastrointestinal tracts (GIT). In this study, we focus on major livestock and domestic animals and show that the levels of Chia mRNA in their stomach tissues are governed by the feeding behavior. Chia mRNA levels were significantly lower in the bovine (herbivores) and dog (carnivores) stomach than those in mouse, pig and chicken (omnivores). Consistent with the mRNA levels, Chia protein was very low in bovine stomach. In addition, the chitinolytic activity of E. coli-expressed bovine and dog Chia enzymes were moderately but significantly lower compared with those of the omnivorous Chia enzymes. Recombinant bovine and dog Chia enzymes can degrade chitin substrates under the artificial GIT conditions. Furthermore, genomes of some herbivorous animals such as rabbit and guinea pig do not contain functional Chia genes. These results indicate that feeding behavior affects Chia expression levels as well as chitinolytic activity of the enzyme, and determines chitin digestibility in the particular animals.

Serum chitotriosidase enzyme activity is closely related to HbA1c levels and the complications in patients with diabetes mellitus type 2

AIMS

Chitotriosidase, is a macrophage sourced enzyme which shows high activity during the course of various storage disorders such as Gaucher's Disease. The aforementioned macrophage sourced enzyme, which has a role in basic immune response, is also high in patients with diabetes. This study was designed to determine the chitotriosidase activities in patients with diabetes and the relationship between the complication of diabetes and chitotriosidase activity.

MATERIALS METHODS

This study included 76 patients with type2 diabetes mellitus and 76 healthy subjects. The chitotriosidase activity of all serum samples were determined by fluorometric method.

RESULTS AND CONCLUSION

The chitotriosidase activity of patients having complications (neuropathy or nephropathy) were statistically significantly higher (p<0.05) than those of the controls. When the chitotriosidase activity of patients was evaluated regarding their glycosylated hemoglobin (HbA1c) levels, a progressive increase in chitotriosidase activity was observed in patients. The chitotriosidase activity of patients having higher HbA1c>10% levels was statistically significant higher than those of the control group's (p<0.05). It is shown that chitotriosidase activity might be a marker for some complications and is closely related to HbA1c levels.

Functional Properties of Mouse Chitotriosidase Expressed in the Periplasmic Space of Escherichia coli

Chitotriosidase (Chit1) is an enzyme associated with various diseases, including Gaucher disease, chronic obstructive pulmonary disease, Alzheimer disease and cystic fibrosis. In this study, we first expressed mouse mature Chit1 fused with V5 and (His)₆ tags at the C-terminus (Chit1-V5-His) in the cytoplasm of Escherichia coli and found that most of the expressed protein was insoluble. In contrast, Chit1 tagged with Protein A at the N-terminus and V5-His at the C-terminus, was expressed in the periplasmic space of E. coli as a soluble protein and successfully purified. We evaluated the chitinolytic properties of the recombinant enzyme using 4-nitrophenyl N,N’-diacetyl-β-D-chitobioside [4NP-chitobioside, 4NP-(GlcNAc)₂] and found that its activity was comparable to CHO cells-expressed Chit1-V5-His. Optimal conditions for the E. coli-produced Chit1 were pH ~5.0 at 50°C. Chit1 was stable after 1 h incubation at pH 5.0~11.0 on ice and its chitinolytic activity was lost at pH 2.0, although the affinity to chitin remained unchanged. Chit1 efficiently cleaved crystalline and colloidal chitin substrates as well as oligomers of N-acetyl-D-glucosamine (GlcNAc) releasing primarily (GlcNAc)₂ fragments at pH 5.0. On the other hand, (GlcNAc)₃ was relatively resistant to digestion by Chit1. The degradation of 4NP-(GlcNAc)₂ and (GlcNAc)₃ was less evident at pH 7.0~8.0, while (GlcNAc)₂ production from colloidal chitin and (GlcNAc)₆ at these pH conditions remained strong at the neutral conditions. Our results indicate that Chit1 degrades chitin substrates under physiological conditions and suggest its important pathophysiological roles in vivo.

Increased chitotriosidase activity in plasma of patients with type 2 diabetes

INTRODUCTION

Chitotriosidase (CHIT1) is a chitinolytic enzyme involved mainly in the immune and inflammatory response. It shows increased activity in many pathologies, including in newly diagnosed type 2 diabetes (T2D). This study aimed to investigate this enzyme's activity in plasma of patients with ongoing T2D and indicate factors related to the increased activity of this enzyme.

MATERIAL AND METHODS

Ninety-one patients and 46 control subjects without abnormalities in carbohydrate metabolism and inflammatory states were enrolled in the study. Plasma CHIT1 activity was measured by a spectrofluorometric method. Routine laboratory parameters such as blood glucose, total cholesterol and HDL fraction, triglyceride, glycated hemoglobin, white blood cell count and C-reactive protein were measured by standard methods.

RESULTS

We found that the chitotriosidase activity was significantly higher (p < 0.001) in type 2 diabetic patients and positively associated with parameters of glycemic control (levels of glucose and glycated hemoglobin) and blood pressure. Plasma glucose level and systolic blood pressure were independent determinants of increased CHIT1 activity in T2D patients, even after adjustment for disease duration, body mass index, parameters of inflammation and lipid metabolism. We also found that increased CHIT1 activity was associated with occurrence of diabetic angiopathies.

CONCLUSIONS

This investigation indicates a possible role of chitotriosidase in the course of T2D, especially in relation to development of diabetic angiopathies.

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.

Immunomodulatory Effects of Chitotriosidase Enzyme

Chitotriosidase enzyme (EC: 3.2.1.14) is the major active chitinase in the human body. It is produced mainly by activated macrophages, in which its expression is regulated by multiple intrinsic and extrinsic signals. Chitotriosidase was confirmed as essential element in the innate immunity against chitin containing organisms such as fungi and protozoa; however, its immunomodulatory effects extend far beyond innate immunity. In the current review, we will try to explore the expanding spectrum of immunological roles played by chitotriosidase enzyme in human health and disease and will discuss its up-to-date clinical value.

Neutrophils as a Source of Chitinases and Chitinase-Like Proteins in Type 2 Diabetes

PURPOSE

The pathophysiological role of human chitinases and chitinase-like proteins (CLPs) is not fully understood. We aimed to determine the levels of neutrophil-derived chitotriosidase (CHIT1), acidic mammalian chitinase (AMCase) and chitinase 3-like protein 1 (YKL-40) in patients with type 2 diabetes (T2D) and verify their association with metabolic and clinical conditions of these patients.

METHODS

Neutrophils were obtained from the whole blood by gradient density centrifugation from 94 T2D patients and 40 control subjects. The activities of CHIT1 and AMCase as well as leukocyte elastase (LE) were measured fluorometrically and concentration of YKL-40 immunoenzymatically. Also, routine laboratory parameters in serum/plasma were determined by standard methods.

RESULTS

The levels of all three examined proteins were about 2-times higher in diabetic patients in comparison to control subjects. They were significantly correlated with the activity of LE and increased progressively across tertiles of LE activity. Moreover, the activities of CHIT1 and AMCase were significantly correlated with each other. Metabolic compensation of diabetes did not influence the levels of these proteins. In the subgroup of patients with inflammatory evidence only YKL-40 concentration was significantly higher compared to those without inflammation. The highest levels of all three proteins were observed in patients with macroangiopathies. Insulin therapy was associated with lower levels of examined proteins.

CONCLUSIONS

We revealed that neutrophils may be an important source of the increased levels of chitinases and CLPs in T2D, and these proteins may participate in inflammatory mechanisms in the course of the disease and consequent development of diabetic angiopathies.

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.

Role of chitotriosidase (chitinase 1) under normal and disease conditions

Mammalian chitinases belong to the glycosyl hydrolase 18 family based on structural homology and the family includes a large number of bacterial and eukaryotic chitinases. Among the mammalian chitinases, chitotriosidase (CHIT1) and acidic mammalian chitinase (AMCase) are capable of hydrolyzing the β-(1, 4)-linkage between the adjacent N-acetyl glucosamine residues of chitin. CHIT1 is one of the most abundantly secreted proteins, being mainly produced by activated macrophages and epithelial cells. CHIT1 plays a pivotal role in the context of infectious disease including malaria and fungi infections as a host defense towards chitin in pathogen's cell structure and as a diagnostic marker of disease. In contrast, CHI1 released by activated Kupffer cells in liver could induce hepatic fibrosis and cirrhosis. Increased serum levels of CHIT1 were observed in patients with many disorders, including Gaucher's disease, bronchial asthma, and atherosclerosis. Therefore, CHIT1 seems to have dual (regulatory and pathogenic) roles depending on the disease and producing cell types during the inflammatory conditions.

Serum chitotriosidase activity: is it a new inflammatory marker in obese children?

Chitotriosidase (ChT) is an enzyme secreted by activated macrophages and involved in defense against, and in degradation of chitin-containing pathogens, such as fungi, nematodes, and insects. In addition, it plays an important role in the development of atherosclerosis related with systemic low-grade inflammation. To this effect of activity of ChT, we aimed to investigate serum ChT activity in obese subjects and to determine to relation with insulin resistance and high-sensitive C-reactive protein (hsCRP). A total of 73 obese subjects (10.9 +/- 2.6 years of age, 44 male patients) and 41 age and gender-matched healthy lean subjects (11.6 +/- 2.9 years of age, 18 male patients) were included in this study, between 2007 and 2008. The criterion for diagnosing obesity was defined as the body mass index (BMI) being over 97th percentile of the same gender and age. Fasting serum glucose, insulin, hsCRP and ChT levels were measured. We compared the differences in variables between obese and lean subjects with Student's t-test compared after ascertaining that the data were normally distributed. All data were expressed as mean +/- standard deviation. There was statistically significant increase in serum ChT activity of obese subjects, while there was statistically significant difference in serum hsCRP levels when compared to healthy lean subjects (30.0 +/- 17.9 and 23.0 +/- 17.8, p=0.045; 2.3 +/- 3.1 and 0.7 +/- 1.2, p=0.001). Obese subjects had significantly higher BMI-SDS, TG and HOMA-IR and lower HDL-C levels when compared with the healthy lean subjects (p<0.05). Correlation analysis showed no significant correlation between serum ChT activity and hsCRP, HOMA-IR and BMI-SDS (p>0.05). Although the data need to be validated by further investigation, the observations made in this study seem to indicate that serum ChT activity may not be a useful marker for monitoring systemic low-grade inflammation and insulin resistance in obese subjects.