Contents lists available at ScienceDirect Tissue and Cell journal homepage: www.elsevier.com/locate/tice Unusual shape and structure of lymphocyte nuclei is linked to hyperglycemia in type 2 diabetes patients T. Martinovic a , D. Ciric a , I. Pantic b,c , K. Lalic d , I. Rasulic e , S. Despotovic a , I. Lalic a , D. Djuricic f , V. Bumbasirevic a , T. Kravic-Stevovic a, ⁎ a Institute of Histology and Embryology, School of Medicine, University of Belgrade, Visegradska 26, Belgrade, Serbia b Institute of Medical Physiology, Laboratory for Cellular Physiology, School of Medicine, University of Belgrade, Visegradska 26, Belgrade, Serbia c University of Haifa, 199 Abba Hushi Blvd. Mount Carmel, Haifa IL-3498838, Israel d Clinic for Endocrinology, Diabetes and Metabolic Disease, Clinical Center of Serbia, School of Medicine, University of Belgrade, Doktora Subotica 13, Belgrade, Serbia e Clinic for Endocrinology, Diabetes and Metabolic Disease, Clinical Center of Serbia, Doktora Subotica 13, Belgrade, Serbia f Health Center “Savski Venac”, Pasterova 1, Belgrade, Serbia ARTICLE INFO Keywords: Fractal analysis Nucleus Diabetes Glucose Lymphocyte Electron microscopy ABSTRACT Type 2 diabetes is an endocrine disorder characterized with hyperglycemia, hyperinsulinemia and insulin re- sistance. Morphological changes in cell nuclei in diabetes were recently detected. The aim of this study was to compare electron microscopic features of lymphocyte nuclei in type 2 diabetes and healthy individuals using conventional computer assisted methods, fractal analysis and gray level co-occurrence matrix (GLCM) analysis of nuclear chromatin. Mononuclear cells taken from the peripheral blood of newly diagnosed type 2 diabetes patients, metformin treated type 2 diabetes patients and healthy individuals were analyzed with transmission electron microscope. Irregular nuclear contours and lower amount of heterochromatin in lymphocytes were detected with conventional computer assisted methods in type 2 diabetes. Fractal analysis of chromatin struc- tures and GLCM angular second moment (ASM) analysis detected differences in nuclear structure between metformin treated type 2 diabetes and two other groups. Irregularities in lymphocyte nuclei correlated with blood glucose, but not with cholesterol and triglyceride levels. Decrease in fractal dimension, indicating lower level of complexity, increase in GLCM ASM, indicating higher texture uniformity, and higher amount of eu- chromatin that we found in metformin treated type 2 diabetes could be indicators of higher transcriptional activity in these cells. 1. Introduction Diabetes is a common endocrine-metabolic disorder (World Health Organization, 2014). One of the main hallmarks in diabetes is hy- perglycemia, accompanied with disturbances in the metabolism of carbohydrate, fat, and proteins due to the absolute or relative insulin deficiency (World Health Organization, 2014). The general categories of diabetes are type 1 (previously known as insulin-dependent diabetes) and type 2 (previously known as non-insulin-dependent diabetes) dia- betes (Kasper et al., 2017). Autoimmunity is a well-known pathogenic component in type 1 diabetes (Clark et al., 2017) and recent findings of circulating autoantibodies against beta cells in type 2 diabetes (Subauste et al., 2014; Irvine et al., 1977), as well as the self-reactive T cells (Brooks-Worrell et al., 2011) led to the assumption that the pa- thogenesis of type 2 diabetes also includes autoimmune aspects. Metformin is an oral drug used in type 2 diabetes to treat high blood glucose levels (Qaseem et al., 2017). The mechanisms of action of metformin are diverse (He and Wondisford, 2015). Metformin activates 5′ AMP-activated protein kinase (AMPK) through the inhibition of the respiratory chain complex I (Viollet and Foretz, 2013; Owen et al., 2000). On the other hand, there are also many effects that metformin has on cell metabolism that are not mediated by AMPK, such as control of main metabolic pathways in T cells, and consequently control of T cell growth and proliferation (Miller et al., 2013; Ben Sahra et al., 2011; Foretz et al., 2010). Irregularities in nuclear morphology were first published in recent exfoliative cytology studies of oral mucosa cells in patients with type 1 and type 2 diabetes (Oz et al., 2014; Hallikerimath et al., 2011). Au- thors of these publications indicated that diabetes could produce mor- phological changes like binucleation and nuclear membrane irregula- rities in the nuclei of exfoliated buccal epithelial cells (Oz et al., 2014; Hallikerimath et al., 2011). Unusual appearance of nuclei, with deep https://doi.org/10.1016/j.tice.2018.04.005 Received 2 March 2018; Received in revised form 16 April 2018; Accepted 23 April 2018 ⁎ Corresponding author. E-mail address: tamara.kravic-stevovic@med.bg.ac.rs (T. Kravic-Stevovic). Tissue and Cell 52 (2018) 92–100 Available online 24 April 2018 0040-8166/ © 2018 Elsevier Ltd. All rights reserved. T