Oxidative stress (OS) is caused by an imbalance between the production of reactive oxygen species (ROS) in cells and tissues and the ability of the biological system to detoxify these products. In chronic kidney disease (CKD), OS contributes to deterioration of kidney function and disease progression. In patients with end-stage kidney disease undergoing hemodialysis or peritoneal dialysis, OS is further increased and associated with adverse clinical outcomes, including deterioration and subsequent loss of residual renal function, atherosclerosis, hypertension, cardiovascular disease and death. However, currently, there is no consensus or guidelines for the diagnosis and treatment of OS in these patients. Herein, we aim to present the existing data regarding biomarkers of OS, pro-oxidants (oxidized albumin, advanced oxidation protein products, xanthine oxidase/dehydrogenase, nitrite/nitrate, malondialdehyde) and antioxidants (superoxide dismutase, catalase, vitamin E, total antioxidant capacity, N-acetylcysteine) that are most clinically relevant and have been more extensively studied in patients with chronic kidney disease, aiming to provide a clearer understanding of this complex area.

Background and Objectives: Secondary hyperparathyroidism (SHPT) poses a common condition among patients with chronic kidney disease (CKD) due to the chronic stimulation of the parathyroid glands as a result of persistently low calcium levels. As a first option for medical treatment, vitamin D receptor analogs (VDRAs) and calcimimetic agents are generally used. Apart from cinacalcet, which is orally taken, in recent years, another calcimimetic agent, etelcalcetide, is being administered intravenously during dialysis. Materials and Methods: In a 5-year retrospective study between 2018 and 2023, 52 patients undergoing dialysis were studied. The aim of this study is to highlight the possible effects and/or benefits that intravenously administered calcimimetic agents have on CKD patients. A total of 34 patients (65.4%) received cinacalcet and etelcalcetide while parathormone (PTH) and calcium serum levels were monitored on a monthly basis. Results: A total of 29 out of 33 patients (87.9%) that received treatment with etelcalcetide showed a significant decrease in PTH levels, which rose up to 57% compared to the initial values. None of the included patients needed to undergo parathyroidectomy (PTx) due to either extremely high and persistent PTH levels or severe side effects of the medications. It is generally strongly advised that parathyroidectomies should be performed by an expert surgical team. In recent years, a significant decrease in parathyroidectomies has been recorded globally, a fact that is mainly linked to the constantly wider use of new calcimimetic agents. This decrease in parathyroidectomies has resulted in an important decrease in complications occurring in cervical surgeries (e.g., perioperative hemorrhage and nerve damage). Conslusions: Despite the fact that these surgical complications cannot be easily compared to the pharmaceutical side effects, the recorded decrease in parathyroidectomies is considered to be notable, especially in cases of relapse where a difficult reoperation would be considered based on previously published guidelines.

Oxidative stress (OS) is highly prevalent in chronic kidney disease (CKD), yet its clinical significance and association with cardiovascular disease (CVD) has not been yet clearly demonstrated. In this cohort study, 477 adults with CKD at various stages and 20 healthy controls were enrolled. In all participants, an extensive panel of OS biomarkers was measured. Malondialdehyde (MDA) was correlated with glomerular filtration rate (eGFR) and carotid intima media thickness (cIMT) (p = 0.008 and p = 0.024, respectively, according to Spearman’s rho). Advanced oxidation protein products (AOPPs) were correlated with the urine protein-to-creatinine ratio (uPCR), parathormone (PTH) and eGFR (p = 0.048, p = 0.025 and p = 0.045 respectively, according to Spearman’s rho) and oxidized albumin (oxALB) was correlated with PTH (p = 0.032) and pulse wave velocity (PWV) (p = 0.017). The antioxidant enzyme superoxide dismutase (SOD) was correlated with PWV (p = 0.042), urea (p < 0.001), uPCR (p = 0.024), and eGFR (p < 0.001). Meanwhile, catalase (CAT) was correlated with eGFR (p = 0.029) and indices of central pressure. Xanthine oxidase (XO) was correlated with the duration of CVD and PWV. Multivariate analysis showed that kidney function and/or arterial stiffness and CVD were independent predictors of all OS markers.