**Abstract**

Oxidative stress (OS) is implicated as a unifying factor between chronic kidney diseases and cardiovascular diseases. The objective of the study was to compare the oxidant and antioxidant status in patients with PD according to the state of DM. Lipoperoxides (LPO), 8-isoprostanes (8-IP) and nitric oxide (NO) were determined as oxidants and the activity of superoxide dismutase (SOD) and total antioxidant capacity (TAC) as antioxidants in patients with DM and without DM (No-DM). We included 35 patients with DM, 42 No-DM patients and 10 healthy people as a control group (HC). Patients with DM were older (p<0.0001), had higher BMI (p<0.0001), high glucose levels (p<0.0001) and more hypertension (p<0.0001). It was found that LPO levels increased in patients with DM and No-DM vs. HC (p<0.0001). There was a decrease in the levels of 8-IP in DM and No-DM compared to HC (p<0.0001). The levels of NO in patients with DM and No-DM decreased significantly compared to the HC group with 197.97±34.20 μM (p<0.0001). The activity of the SOD enzyme in patients with DM and No-DM was found to be increased compared to the HC group (p<0.0001). The levels of TAC in HC were 2.62±0.17 mM and decreased in patients with DM and No-DM (p<0.0001).

**Keywords:** end-stage renal disease, chronic kidney disease, peritoneal dialysis, diabetes mellitus, oxidative stress, antioxidants

#### **1. Introduction**

Several traditional and nontraditional cardiovascular risk factors have been described in chronic kidney disease (CKD). Cardiovascular disease (CVD) still is the leading cause of death among end-stage renal disease (ESRD) patients. CVD and CKD are closely related to each other, and the disease of one of the organs causes dysfunction of the other by conditioning the failure of both organs [1]. CKD patients generally have several traditional cardiovascular risk factors like diabetes mellitus (DM), dyslipidemia, and arterial hypertension. These conditions are associated with oxidative stress (OS), and these can trigger and accelerate the progression of renal injury [2]. OS is defined as the imbalance between oxidants and the antioxidant defenses of the body. Reactive oxygen species (ROS) are generated through enzymes such as nicotinamide phosphate adenine dinucleotide (NADPH) oxidase, which reduces oxygen to superoxide anion (O2<sup>−</sup>). This anion is converted to hydrogen peroxide (H2O2) by the enzyme superoxide dismutase (SOD). The O2<sup>−</sup> anion reacts with nitric oxide (NO) by producing peroxynitrite (nitrosative stress). The H2O2 reacts with intracellular iron to form the hydroxyl radical. In addition, H2O2 is catalyzed to hypochlorous acid in the presence of the chloride ion, by myeloperoxidase activity. Uremic toxins also participate by increasing ROS generation. The excessive production of ROS is able to oxidize lipids, proteins, and nucleic acids [3].

DM is a frequent cause of the need for renal replacement therapy (RRT) [4]. In Jalisco (Mexico), nearly half of the patients in dialysis are on peritoneal dialysis (PD), and almost half of these patients have DM [5]. In 2009, it was reported that diabetic nephropathy (DN) causes ~44% of all cases of ESRD in the United States [6]. DM contributes, in large part, to the high costs of health care and the increase in mortality from the increased incidence of DN that leads to ESRD [7]. The purpose of the study was to compare the oxidants and antioxidants state in patients with PD according to DM status.
