ORIGINAL ARTICLE Reduced muscle carnosine content in type 2, but not in type 1 diabetic patients Bruno Gualano • Inge Everaert • Sanne Stegen • Guilherme Giannini Artioli • Youri Taes • Hamilton Roschel • Eric Achten • Maria Concepcio ´n Otaduy • Antonio Herbert Lancha Junior • Roger Harris • Wim Derave Received: 10 October 2011 / Accepted: 17 November 2011 / Published online: 27 November 2011 Ó Springer-Verlag 2011 Abstract Carnosine is present in high concentrations in skeletal muscle where it contributes to acid buffering and functions also as a natural protector against oxidative and carbonyl stress. Animal studies have shown an anti-diabetic effect of carnosine supplementation. High carnosinase activity, the carnosine degrading enzyme in serum, is a risk factor for diabetic complications in humans. The aim of the present study was to compare the muscle carnosine con- centration in diabetic subjects to the level in non-diabetics. Type 1 and 2 diabetic patients and matched healthy controls (total n = 58) were included in the study. Muscle carnosine content was evaluated by proton magnetic resonance spectroscopy (3 Tesla) in soleus and gastrocnemius. Sig- nificantly lower carnosine content (-45%) in gastrocnemius muscle, but not in soleus, was shown in type 2 diabetic patients compared with controls. No differences were observed in type 1 diabetic patients. Type II diabetic patients display a reduced muscular carnosine content. A reduction in muscle carnosine concentration may be partially associ- ated with defective mechanisms against oxidative, glycative and carbonyl stress in muscle. Keywords Skeletal muscle Á Glycation Á AGEs Á Oxidative stress Á Carbonyl stress Á Carnosine Á Beta-alanine Á Diabetic complications Á MRS Abbreviations CN-1 Carnosinase-1 CNDP-1 Carnosine dipeptidase-1 gene HNE 4-Hydroxynonenal MRS Magnetic resonance spectroscopy Introduction Hyperglycemia results in exacerbated oxidative stress and glycation, both responsible for the harmful lipid and pro- tein glycoxidation products such as 4-hydroxynonenal (HNE), advanced glycation end products (AGE’s) and protein carbonyls. Carnosine (b-alanine-L-histidine) is a dipeptide predominantly and abundantly found in skeletal muscle where it contributes to pH regulation over the physiological pH-transit range (Artioli et al. 2010; Derave et al. 2010; Sale et al. 2010). In vitro studies indicate that carnosine also has the potential to act as a scavenger of reactive oxygen species, reactive aldehydes and ketones, protein carbonyls, and inflammatory species (Boldyrev B. Gualano (&) Á G. G. Artioli Á H. Roschel Á A. H. L. Junior Á R. Harris Department of Biodynamic of Human Movement, School of Physical Education and Sports, University of Sao Paulo, Av. Prof. Mello Moraes, 65 Butanta, Sao Paulo, SP 05508-030, Brazil e-mail: gualano@usp.br I. Everaert Á S. Stegen Á W. Derave Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium Y. Taes Department of Endocrinology, Ghent University Hospital, Ghent, Belgium E. Achten Department of Radiology and Nuclear Medicine, Ghent Institute for functional and Metabolic Imaging (GIfMI), Ghent University, Ghent, Belgium M. C. Otaduy Department of Radiology, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil 123 Amino Acids (2012) 43:21–24 DOI 10.1007/s00726-011-1165-y