Criteria:  The following criteria of qualifying for the study were adopted for all respondents:  18 years of age or older, written consent to participate in the study, no active inflammatory process, no neoplastic disease or a neoplastic disease whose treatment was stopped at least 10 years ago, no history of immunosuppressive treatment, stable liver function (not more than two times increased activity of transaminases), HBs antigen and anti-HCV negative antibodies,anti-HIV negative antibodies.  In addition, for CKD patients (CKD1-2) and PREDIALYSIS GROUP, the following additional inclusion conditions were applied:  no acute cardiovascular complications, ie acute heart failure, hypertensive crisis, acute coronary syndrome, at the time of study entry.  At the same time, depending on the technique of renal replacement therapy used, additional inclusion criteria were established for each of the subgroups:  in group HD:  a minimum of 6 months of treatment with repeated hemodialysis, 3 times a week, for a minimum of 10 hours a week, arteriovenous fistula as a vascular access for hemodialysis, Estimated dialysis adequacy ratio (eKt / V) of at least 1.2. in the PD group: treatment duration UP to a minimum of 6 months, Kt / V ≥1.8 l / week / 1.73 m2.  For CARD patients, additional conditions include:  no obvious evidence of renal impairment in the history and at the time of study entry, renal function assessed on the basis of eGFR and urine albumin/creatinine ratio, history of angina pectoris, documented history of at least one acute coronary syndrome, admission to the Department of Intensive Care of Cardiology and Internal Diseases in order to perform a planned coronary angiography, on the day of admission to the study without signs of the acute coronary syndrome, no additional comorbidities, ie those that do not result directly or indirectly from coronary heart disease.  In turn, for the HV group (control group), additional conditions include:  no obvious evidence of renal impairment in the history and at the time of study entry, renal function assessed on the basis of eGFR and urine albumin/creatinine ratio, no obvious signs of cardiovascular impairment in the history and at the time of study entry, estimated on the basis of normal blood pressure (<140/90 mmHg), no abnormalities in the medical history and physical examination, not taking any medications on a regular basis.