Olga Beresneva

Chronic kidney disease—mineral and bone disorder (CKD-MBD) plays a significant role in causing cardiovascular morbidity and mortality related to CKD. CKD-MBD has been studied during advanced stages when changes in inorganic phosphate (Pi) and its hormonal regulation are obvious. The initial phases of myocardial remodeling (MR) in early CKD-MBD remain poorly understood. We induced mild CKD-MBD in spontaneously hypertensive rats using 3/4 nephrectomy. Animals were fed standard chow, containing 0.6% phosphate. In each animal, we analyzed indices of chronic kidney injury, bone turnover and Pi exchange, and assessed the myocardial histology and gene expression profile. Applied CKD-MBD models corresponded to human CKD S1-2 with low bone turnover and without an increase in systemic Pi-regulating factors (parathyroid hormone and fibroblast growth factor 23). In mild CKD-MBD models, we found MR features characterized by cardiomyocyte hypertrophy, interstitial and perivascular fibrosis, intramyocardial artery media thickening, along with alterations in Ppp3ca, Mapk1, Jag1, Hes1, Ptch1, Numb, Lgr4 and Bmp4 genes. Among other genes, the down-regulation of Jag1 was most tightly associated with either myocardial hypertrophy or fibrosis. Myocardial alterations concurrently occurred with mild CKD-MBD and comprised fibrosis preceding cardiomyocyte hypertrophy. The histological features of MR were associated with myocardial P accumulation in settings of low bone turnover, prior to a response of systemic Pi-regulating factors and with alterations in calcineurin, ERK1/2, Notch, BMP and Hedgehog genes.

Cardioprotective Effect of Soy Protein on a High-Salt Diet in Cynomolgus Monkeys Кардиопротективное действие соевого белка при высокосолевой диете у яванских макак

Excessive salt intake is accompanied by the development of cardiovascular disorders, not always associated with an increase in blood pressure (BP). Given the cardioprotective effect of soy proteins in chronic kidney disease, the question arose of the possibility of leveling dietary interventions, in particular soy proteins, the damaging effect of a high-salt diet on the cardiovascular system. The aim of this work is to study the effect of long-term use of a diet high in NaCl and soy protein on myocardial remodeling and skin histomorphology in monkeys. The study was performed on male Javan macaques (Macaca fascicularis). The control group received a standard diet (2 g NaCl/kg feed). The second was a high-salt diet (8 g NaCl/kg feed), the third was a high-salt diet and SUPRO760 soy protein (200 g/kg feed). Echocardiography, registration of BP and heart rate were performed at baseline, after 4 and 12 months. After 12 months, a histological examination of the musculocutaneous flap was performed. In all animals, BP and heart rate did not change significantly during 12 months. In macaques on a high-salt diet, by the end of the study, deterioration in systolic and diastolic functions of the left ventricle (LV) was noted. In animals receiving additional soy protein, these changes leveled out. After 12 months, macaques fed soy protein had LV myocardial mass smaller and higher LV contractility than animals fed excess salt without soy protein. In monkeys on a high-salt diet, accumulation of collagen fibers in the hypodermis, hyalinization of the cytoplasm of capillary smooth muscle cells, perivascular and perineural edema of the reticular dermis were revealed. In animals treated with soy protein, skin capillary remodeling was less pronounced. Thus, high salt intake leads to adverse structural and functional disorders of the heart and blood vessels in cynomolgus monkeys, not associated with an increase in blood pressure. The inclusion of soy isolate in the diet reduces the negative effects of a high-salt diet on the cardiovascular system.

The initial phases of molecular and cellular maladaptive bone responses in early chronic kidney disease (CKD) remain mostly unknown. We induced mild CKD in spontaneously hypertensive rats (SHR) by either causing arterial hypertension lasting six months (sham-operated rats, SO6) or in its’ combination with 3/4 nephrectomy lasting two and six months (Nx2 and Nx6, respectively). Sham-operated SHRs (SO2) and Wistar Kyoto rats (WKY2) with a two-month follow-up served as controls. Animals were fed standard chow containing 0.6% phosphate. Upon follow-up completion in each animal, we measured creatinine clearance, urine albumin-to-creatinine ratio, renal interstitial fibrosis, inorganic phosphate (Pi) exchange, intact parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), Klotho, Dickkopf-1, sclerostin, and assessed bone response by static histomorphometry and gene expression profiles. The mild CKD groups had no increase in renal Pi excretion, FGF23, or PTH levels. Serum Pi, Dickkopf-1, and sclerostin were higher in Nx6. A decrease in trabecular bone area and osteocyte number was obvious in SO6. Nx2 and Nx6 had additionally lower osteoblast numbers. The decline in eroded perimeter, a resorption index, was only apparent in Nx6. Significant downregulation of genes related to Pi transport, MAPK, WNT, and BMP signaling accompanied histological alterations in Nx2 and Nx6. We found an association between mild CKD and histological and molecular features suggesting lower bone turnover, which occurred at normal levels of systemic Pi-regulating factors.

Background: Initial phases of molecular and cellular maladaptive bone response at early CKD remain mostly unknown. Methods: We induced mild CKD in SHRs by either arterial hypertension lasting six months (sham-operated rats, SO6) or in its’ combination with 3/4 nephrectomy lasting two and six months (Nx2 and Nx6, correspondently). Sham operated SHRs (SO2) and Wistar Kyoto rats (WKY2) with two-month follow-up served as controls. Animals were fed standard chow containing 0.6% phosphate. We measured creatinine clearance, urine albumin-to-creatinine ratio, renal interstitial fibrosis, inorganic phosphate (Pi) exchange, intact PTH and FGF23, Klotho, dickkopf-1, sclerostin. And assessed bone response by static histomorphometric indices and gene expression profiles. Results: Mild CKD groups had no increase in renal Pi excretion, FGF23 and PTH levels. Serum Pi, dickkopf-1, and sclerostin were higher in Nx6. Decrease in trabecular bone area and osteocyte number was obvious in SO6. Nx2 and Nx6 had additionally lower osteoblast number. The decline in eroded perimeter was only apparent in Nx6. Significant downregulation of genes related to Pi transport, MAPK, WNT, and BMP signaling accompanied histological alterations in Nx2 and Nx6. Conclusions: We found an association of mild CKD with histological and molecular features suggesting lower bone turnover, which occurred at normal levels of systemic Pi-regulating factors.

Background: Arterial hypertension (AH) is associated with heart and chronic kidney disease (CKD). However, the precise mechanisms of myocardial remodeling (MR) in the settings of CKD remain elusive. We hypothesized that TRPC6, calcineurin/NFAT, and Wnt/β-catenin signaling pathways are involved in the development of MR in the background of CKD and AH. Methods: Early CKD was induced by performing a 5/6 nephrectomy (5/6NE) in spontaneously hypertensive rats (SHR-NE). Sham-operated (SO) SHR (SHR-SO) and Wistar Kyoto (WKY-SO) rats served as controls. Systolic blood pressure (SBP), heart rate, myocardial mass index (MMI), serum creatinine, cardiomyocyte diameter (dCM), myocardial fibrosis (MF), serum and kidney α-Klotho levels, myocardial expression of calcineurin (CaN), TRPC6, and β-catenin were measured two months after 5/6NE or SO. Results: NE-induced kidney dysfunction corresponded to mild-to-moderate human CKD and was associated with an increase in FGF23 and a decrease in renal α-Klotho. The levels of SBP, MMI, dCM, and MF were higher in SHRs compared to WKY-SO as well as in SHR-NE vs. SHR-SO. The MR was associated with increased cardiomyocyte expression of CaN/NFAT and β-catenin along with its intracellular re-distribution. TRPC6 protein levels were substantially elevated in both SHR groups with higher Trpc6 mRNA expression in SHR-NE. Conclusions: The Wnt/β-catenin and TRPC6/CaN/NFAT hypertrophic signaling pathways seem to be involved in myocardial remodeling in the settings of AH and CKD and might be mediated by FGF23 and α-Klotho axis.

THE AIM: to estimate the level of expression miRNA-21 inthe urine and renal tissue in rats with unilateral ureteral obstruction (UUO). MATHERIAL AND METHODS. UUO was induced by ligation of the left ureter in male Wistar rats (n=10). Follow-up period was 14 days after UUO modeling. Urine was collected one day before the operation (UmiRNA21_C), and one day before the end of experiment (UmiRNA21I ) during 24 hours. Before releasing animal out of experiment collected urine from left kidney pelvis (UmiRNA21O) and tissue of left kidney (KmiRNA21_O) and right kidney (KmiRNA21_I). MiRNA-21 expression in kidney tissues and urine was carried out with reaction amplification (RealTime PCR-protocol). Calculation was realized by 2-^deltaCtmethod. Statistical analysis was performed with Wilcoxon test and Spearman correlation coefficient. Results are demonstrated as median [low – upper quartile]. RESULTS. UmiRNA21_I(3.78[2.0-5.28]) and UmiRNA21_O(3.78[3.25-3.82]) were significantly higher than UmiRNA21C (1.15[0.71-1.74]; P=0.0125 and P=0.0069, respectively). UmiRNA21I and UmiRNA21O values were practically equal. In kidneys with UUO the tissue levels of miRNA21 expression was a higher than in contralateral organ (P=0,0926). Revealed direct correlation between KmiRNA_Iand KmiRNA_O(RS=0,770, P=0,0092). CONCLUSION. UOO can cause specific changes in the expression, distribution and excretion of micro RNA-21 and its role in the development of renal tubulointestitsial fibrosis requires further studies. Key words: miRNA-21, tubulointerstitial fibrosis, unilateral ureteral obstruction

The article is devoted to the outstanding scientist anatomist, paleontologist, doctor of biological sciences, lieutenant-colonel of medical service A. P. Bystrov (1899–1959), who lived only 60 years. Twenty-five years he was connected with the military department, two years worked inMoscowin the Paleontological Institute, the last 13 years of his life he taught at the geological faculty ofLeningradstate university.