The main function of the kidneys is the maintenance of water-salt homeostasis. Hormonal mechanisms of kidney function allow it to participate in the regulation of many body functions. This is achieved by the consistent work of transport systems of the kidneys, and the hormonal (endocrine, paracrine, autocrine) mechanisms. In a brief overview we show the involvement of the kidneys in some physiological and pathological processes which require precise coordination of hormonal and transport systems of the kidneys and the whole body. The peculiarity of involvement of the kidney through angiotensin II in the development of the fetus during pregnancy is described. Flexibility and plasticity of regulation of water-salt metabolism in various forms of pathology can be attributed to these functions of the kidneys to the category of homeostasis.

Acute neurologic involvement is a life threatening and not rare (>20%) complication of the STEC-HUS in children and often determines prognosis and outcome of the disease. The most frequent neurologic signs are seizures (>70%), impaired consciousness (70-80%), coma (≈20%), paresis, oculomotor disturbances. The prognosis of typical HUS has improved over the last decades mainly due to the better general medical care resulting in lower mortality rate in pediatric STEC-HUS. More than 50% of children completely recovered from their neurological complication. This review reports current state of pathogenesis, clinical features and treatment approaches for typical STEC-HUS with neurological complications. A lot of data are concerned of the recent outbreak of HUS caused by shiga toxin producing E.coli O104:Н4, but clinical feature and short-term outcome in pediatric patients were similar to previous outbreaks of STEC-HUS. The treatment modalities in children were generally less aggressive than those in adult patients. Most of children with O104:H4 HUS (74%) recovered with supportive treatment alone, including those with neurological complications. Plasmapheresis was performed in 19% pediatric patients, mainly with neurological complications (n=16). Retrospective analysis of treatment strategies showed no significant short term benefit of eculizumab compared with patients with the same severity of HUS treated with plasmapheresis. IgG-immunoadsorption turned out to be unexpectedly effective in treating the severe neurological complications of HUS, but antibody-mediated theory of CNS injury in HUS is not yet proved. Current treatment approaches will undoubtedly allow one to treat typical HUS with severe complications in children more successfully.

Disarrangement of bone metabolism and vascular calcification significantly contribute to the development of cardiovascular complications in patients with reduced kidney function, thereby determining the worst survival in this group of patients. In recent years, more attention has been paid to search and research of markers of bone damage that are associated with the development of a number of systemic complications in patients with chronic kidney disease, including patients on renal replacement therapy. Wnt-signaling pathway consists of a number of complex proteins, constantly interacting with each other and determining not only normal embryogenesis, but also bone metabolism. Sclerostin by inhibiting Wnt-signaling pathway alters bone formation by suppressing the proliferation and differentiation of osteoblasts. Patients with impaired renal function have elevated serum levels of sclerostin due to its enhanced synthesis. However, until now it is not known whether sclerostin is a predictor of poor prognosis in patients with CKD, or it acts as a kind of protector of vascular wall from calcification, thus ensuring a better survival of both vascular access and patients in general. The review presents recent data on a role of sclerostin in bone metabolism, its participation in the processes of bone remodeling in patients with renal insufficiency, as well as potential therapeutic strategies aimed at changing the concentration of the protein.

Aim: to analyze changes in kidney function in early postoperation period, 3 months and one year after CABG without cardiopulmonary bypass (CPB) and to estimate the potential of the serum kidney injury molecule I type (KIM-1) and the high-sensitivity С-reactive protein (hsCRP) as the tool for identification which patients would develop worsening of the glomerular filtration rate (eGFR). We studied 141 patients after CABG without CPB. The frequency of acute kidney injury (AKI) and prognostic factors of its development were estimated. We found that the initial high eGFR, female gender and proteinuria are associated with the development of the AKI in this category of patients. In 30 patients, we additionally have evaluated the changes in serum KIM-1 and hsCRP levels before and in the early period after CABG by Elisa test, and the long-term outcome of kidney function. There are evidences that both biomarkers can be used for long-term prognosis.

Arterial stiffness is a cardiovascular risk factor. The present research was performed in order to determine the factors influencing arterial stiffness in patients on hemodialysis and kidney transplant recipients. We examined 75 patients with ESRD (42 males and 33 females, age 49 ± 14 years) receiving renal replacement therapy (RRT), 58 of them were on hemodialysis, 17 had a functioning kidney transplant. The pulse wave velocity index (PWV) was used to assess arterial stiffness. It was calculated according to the contour of the peripheral pulse wave analysis. Correlation analysis in the group of dialysis patients revealed that PWV has negative correlation of medium strength with BMI (rs=-0.31, p=0.02). In the group of kidney transplant recipients correlation analysis showed that PWV correlated with the age of patients (rs=0.65; p=0.005) and the total cholesterol level (rs= 0.51; p= 0.04). Hemodialysis patients have increased arterial stiffness after dialysis, that was associated with the volume of ultrafiltration; stiffness is an additional factor of cardiovascular risk in these patients.

Hemodialysis is the major method in renal replacement therapy. Its quality, the concurrency of complications, as well as the survival rate and rehabilitation of patients are largely determined by adequate permanent vascular access, the best option of which is the native arteriovenous fistula. A study of the flow in microvascular system of the hand after formation of arteriovenous fistula in patients with end-stage renal disease was performed by laser Doppler method. It was shown that the formation of an radiocephalic arteriovenous fistula reduces tissue perfusion below the anastomosis. Endothelial component of the microvascular tone of skin decreases, which leads to a decrease in hydrodynamic resistance microvasculature and to an increase in blood flow to the tissues of the hand. Also an increase in neurogenic microvascular tone was found. This leads to constriction of the arteriolo-venular anastomoses, an increase in capillary blood flow and to improvement in the metabolic processes in the hand tissues.

Clinical cases which demonstrate dialysis patients with hemoptysis as the result of pulmonary thromboembolism, overdose of anticoagulants and severe heart failure are presented.

The article presents three clinical variants of renal damage in patients with multiple myeloma. Difficulties in the disease diagnostics are specified.

A clinical observation of the successful treatment of the primary membranous nephropathy, refractory to different modes of immunosuppressive therapy with rituximab is presented.