Print Email Facebook Twitter Evaluation of chitotriosidase as a biomarker for adipose tissue inflammation in overweight individuals and type 2 diabetic patients Title Evaluation of chitotriosidase as a biomarker for adipose tissue inflammation in overweight individuals and type 2 diabetic patients Author Tans, R. van Diepen, J.A. Bijlsma, S. Verschuren, L. Suppers, A. Stienstra, R. Wevers, R.A. Tack, C.J. Gloerich, J. van Gool, A.J. Publication year 2019 Abstract Background: Overweight and obesity can lead to adipose tissue inflammation, which causes insulin resistance and on the long-term type 2 diabetes mellitus (T2D). The inflammatory changes of obese-adipose tissue are characterized by macrophage infiltration and activation, but validated circulating biomarkers for adipose tissue inflammation for clinical use are still lacking. One of the most secreted enzymes by activated macrophages is chitotriosidase (CHIT1). Objective: To test whether circulating CHIT1 enzymatic activity levels reflect adipose tissue inflammation. Methods: Plasma and adipose tissue samples of 105 subjects (35 lean, 37 overweight, and 33 T2D patients) were investigated. CHIT1 mRNA levels were determined in adipose tissue-resident innate immune cells. CHIT1 mRNA levels, protein abundance, and plasma enzymatic activity were subsequently measured in adipose tissue biopsies and plasma of control subjects with varying levels of obesity and adipose tissue inflammation as well as in T2D patients. Results: In adipose tissue, CHIT1 mRNA levels were higher in stromal vascular cells compared to adipocytes, and higher in adipose tissue-residing macrophages compared to circulating monocytes (p < 0.001). CHIT1 mRNA levels in adipose tissue were enhanced in overweightcompared to lean subjects and even more in T2D patients (p < 0.05). In contrast, plasma CHIT1 enzymatic activity did not differ between lean, overweight subjects and T2D patients. A mutation of the CHIT1 gene decreases plasma CHIT1 activity. Conclusions: CHIT1 is expressed by adipose tissue macrophages and expression is higher in overweight subjects and T2D patients, indicating its potential as tissue biomarker for adipose tissue inflammation. However, these differences do not translate into different plasma CHIT1 activity levels. Moreover, a common CHIT1 gene mutation causing loss of plasma CHIT1 activity interferes with its use as a biomarker of adipose tissue inflammation. These results indicate that plasma CHIT1 activity is of limited value as a circulating biomarker for adipose tissue inflammation in human subjects. © 2018, Springer Nature Limited. Chemicals / CAS beta n acetylhexosaminidase, 37211-57-7, 9012-33-3, 9027-52-5; Biomarkers; chitotriosidase; Hexosaminidases; RNA, Messenger Subject CD14 antigenchitotriosidasemessenger RNAbeta n acetylhexosaminidasebiological markerchitotriosidasemessenger RNAadipocytebody compositionbody masscellular distributioncomparative studycontrolled studydiabetic patientdisease associationenzyme activityexongene expressiongene mutationgenetic variationgenotypehuman tissueinnate immunityintra-abdominal fatmacrophagemajor clinical studysoft tissue inflammationsubcutaneous fatbloodchemistrycomplicationgeneticsinflammationmetabolismnon insulin dependent diabetes mellitusobesityAdipose TissueAgedBiomarkersDiabetes Mellitus, Type 2FemaleHexosaminidasesHumansInflammationMaleMiddle AgedOverweightRNA, MessengerLifeMSB - Microbiology and Systems Biology To reference this document use: http://resolver.tudelft.nl/uuid:a050c92f-e6e3-45fa-8ad7-ebeb29de9766 DOI https://doi.org/10.1038/s41366-018-0225-8 TNO identifier 955115 ISSN 0307-0565 Source International Journal of Obesity, 43 (43), 1712-1723 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.