The encoding of the International statistical classifi cation of diseases and related health: N18.1/N18.2/N18.3/N18.4/N18.5/N18.9 with codes of complications and associated conditions (if any) Z49.0/Z49.1/Z49.2/D63.8*/E87.2/E87.5/E21.1/ E83.3/ E83.5/E83.8/ N25.0/E89.2
Age group: adults
Year of approval: 2021 (revision every 3 years)
Developer of the clinical recommendation: Association of Nephrologists

THE AIM: a comprehensive assessment of the frequency, severity, and composition of cognitive impairments (CI) in patients with CKD stages 3A-5D, as well as to study the relationship between the levels of endothelial nitric oxide synthase (eNOS) and these impairments. 
PATIENTS AND METHODS: The study included 80 patients with CKD aged 26 to 79 years (mean age 58.9 ± 1.4 years), among them 43 women (mean age 60.1 ± 1.9 years) and 37 men (mean age 57.4 ± 2.3 years). All patients were divided into 2 groups: group 1 (pre-dialysis) included 40 patients (28 women and 12 men) with CKD 3A-5 (mean age 59.9 ± 2.1 years), group 2 (on dialysis) included 40 patients (18 women and 22 men) with CKD 5D (mean age 58.1 ± 2.1 years). Sarcopenia was verified according to the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP). The presence and severity of CI were determined using the short mental status assessment scale (MMSE) and the Montreal cognitive assessment test (MoCA). To identify endothelial dysfunction, all patients underwent a test with endothelium-dependent vasodilation of the brachial artery, as well as determination of the level of eNOS (ELISA Kit, USA) in serum. 
RESULTS: The prevalence of sarcopenia in the 1st group was 12.5 %, and in the 2nd group, 42.5 %. The average age of patients with sarcopenia was 66.1 ± 2.1 years. The prevalence of CI according to the MoCA scale in the general cohort was 70 %, while in the 1st group – 67.5 %, in the second – 72.5 %, in the subgroup with sarcopenia – 76.2 %. CIs, determined by the MMSE scale, were on average in 67.5 % of the surveyed, and the quantitative prevalence in the groups was identical, however, the qualitative composition of CIs in the comparative analysis differed in the severity of manifestations. In a comparative assessment of the prevalence of CI (according to the MMSE scale) in patients with sarcopenia, it was found that this indicator was significantly higher than in the subgroup without sarcopenia and amounted to 90.5 % and 59.3 %, respectively. In patients with sarcopenia, the level of eNOS was lower than the mean values compared with the general sample, patients of the 1st group and the subgroup without sarcopenia (0.75 ± 0.1 ng / ml, 0.88 ± 0.1 ng / ml, 1 ± 0.1 ng / ml and 0.92 ± 0.2 ng / ml, respectively (p = 0.02)). According to the results of the test with endothelium-dependent vasodilation, the prevalence of endothelial dysfunction in the total cohort of patients was 48.8 % (in the 1st group – 27.5 %, and in the 2nd group – 70 % (p = 0.001)), in the subgroup of patients with sarcopenia – 57.1 %. 
CONCLUSION: A high prevalence of CI was found in patients with CKD. The progression of CKD is associated with the formation of endothelial dysfunction and the development of CI. The latter significantly impairs the quality and life expectancy of patients. The main mechanism of their development is increasing endothelial dysfunction, and eNOS plays a key role in this process. Sarcopenia is associated with an increased risk of CI, regardless of the studied population and the criteria for the diagnosis of sarcopenia, and plays an important prognostic value.

BACKGROUND. To date, the study of the factors involved in the glomerular-tubular pathological connections leading to damage to the tubulointerstitial tissue is one of the topical areas of nephrology. THE AIM: to study the effect of MCP-1 in the development of tubulointerstitial fibrosis as a factor in the irreversible progression of chronic renal failure. PATIENTS AND
METHODS. Prospective observation and retrospective analysis of case histories were carried out, which included a total of 75 patients with primary chronic glomerulonephritis. 
RESULTS. The average age of the patients was 36.7 ± 12.3 years, of which 52 were males, 23 were women. The average length of service in a nephrological disease was 3.0 [1.0; 5.0] years. The calculated GFR values are 87.3 ± 31.2 ml / min / 1.73 m2. In the general population, the moderate degree of MCP-1 expression, estimated at 2 points, was 35 %, pronounced expression was found in 25 % of the respondents. In the mesangium of the glomeruli and in macrophages, the expressed degree of MCP-1 expression was 20 % and 16 %, respectively, which characterizes MCP-1 as a marker produced by resident cells. When studying the relationship of MCP-1 in blood with clinical parameters, a correlation was found with the values of total protein (Rs= –0.43; p <0.05), with erythrocyturia (Rs= –0.28; p <0.05), as well as with an albumin level (Rs= –0.5; p <0.05), which indicates the role of MCP-1 in the development of nephritic forms of glomerulonephritis. Depending on the severity of MCP-1 expression in biopsy specimens, the incidence of focal tubulointerstitial fibrosis with MCP-1 expression estimated at 1 point was 13.3 %, 2 points – 14.3 %, 3 points – 44.0 %. The revealed significant correlation between the serum level of MCP-1 and the severity of tubulointerstitial fibrosis confirms the MCP-1-mediated mechanism of progression of CKD. 
CONCLUSION. The relationship of serum and tissue forms of MCP-1 with the progression of tubulointerstitial fibrosis in chronic glomerulonephritis has been demonstrated. MCP-1-induced mesangial cell plays a critical role in the development of renal tubular damage, and its increased expression is associated with progressive tubulointerstitial fibrosis and decreased renal function.