Research Article Uremic Pruritus Is Not Associated with Endocannabinoid Receptor 1 Gene Polymorphisms Monika Heisig, 1 Aukasz AaczmaNski, 2 Adam Reich, 1 Felicja Lwow, 3 and Jacek C. Szepietowski 1 1 Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, 1 Chalubinskiego Street, 50-368 Wroclaw, Poland 2 Department of Endocrinology and Diabetology, Wroclaw Medical University, 4 Pasteura Street, 50-367 Wroclaw, Poland 3 Department of Health Promotion, University School of Physical Education, 35 Paderewskiego Street, 51-612 Wroclaw, Poland Correspondence should be addressed to Jacek C. Szepietowski; jacek.szepietowski@umed.wroc.pl Received 21 December 2015; Revised 24 January 2016; Accepted 1 February 2016 Academic Editor: Daniela Parolaro Copyright © 2016 Monika Heisig et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Uremic pruritus (UP) is a frequent and bothersome symptom in hemodialysis patients. Its etiology is not fully understood and that is why there is no specifc treatment. Te endocannabinoid system plays a role in many pathological conditions. Tere is reliable evidence on the association between cannabinoid system and pruritus. In our study, we aimed to evaluate whether genetic variations in the endocannabinoid receptor 1 (CNR1) gene can afect UP. Te rs12720071, rs806368, rs1049353, rs806381, rs10485170, rs6454674, and rs2023239 polymorphisms of the CNR1 gene were genotyped in 159 hemodialysis patients and 150 healthy controls using two multiplex polymerase chain reactions and the minisequencing technique. No statistically signifcant relationship was found in any of the evaluated genotypes between patients with and without UP, even afer excluding patients with diabetes and dyslipidemia. Tere were no diferences between patients with UP and the control group. However, in the group of all HD patients, a signifcantly higher incidence of GA genotype and lower incidence in GG genotype in the polymorphism rs806381s were revealed versus the control group ( = 0.04). It seems that polymorphisms of the CNR1 gene are not associated with uremic pruritus. 1. Introduction Uremic pruritus (UP) is a frequent phenomenon and it is regarded as one of the most bothersome symptoms in patients with chronic renal disease [1]. Te prevalence of UP is still high and reported in around 40% to 50% [2, 3]. UP has an important impact on patients’ quality of life and sleep, depression, and increased mortality [3, 4]. Te pathogenesis of UP remains blurry, although many diferent factors have been indicated in the etiology of this symptom, including increased systemic infammation, abnormal serum parathyroid hormone, calcium, and phosphorus levels, an imbalance in opiate receptors, a neuropathic process, or even skin dryness [4, 5]. Tis is why until now there is no specifc treatment for patients with UP and many of the available therapeutic modalities are not satisfactory. Te endocannabinoid system (EC) has an efect on various physiological conditions and since its discovery at the end of twentieth century it has attracted much attention of researchers in diferent felds. It has already been proved that the EC system plays a role in insulin resistance, fat distribution, and metabolic disorders [6, 7]. Moreover, recent studies provided data on the signifcant role of the EC in the cutaneous physiology and pathology [8]. Te EC has two identifed receptors: CNR1 (endocannabinoid receptor 1) and CNR2 (endocannabinoid receptor 2). Both receptors have their ligands which interact with endogenous and exogenous cannabinoids [9]. Te most well-known natural ligands of CNR1 are fatty acid amides (FAAs) or esters represented by anandamide (AEA), N-palmitoylethanolamine (PEA), N- oleoylethanolamine (OEA), or 2-arachidonoylglycerol (2- AG) [7, 10]. Te frst receptor is mainly expressed in central Hindawi Publishing Corporation BioMed Research International Volume 2016, Article ID 3567527, 5 pages http://dx.doi.org/10.1155/2016/3567527