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Objective: Activation of the sympathetic nervous system increases sodium retention in resistant hypertension. Baroreflex activation therapy (BAT) is an interventional method to reduce sympathetic overactivity in patients with resistant hypertension. This study aimed to assess the effect of BAT on urinary sodium excretion., Methods: From 2012 to 2015, consecutive patients with resistant hypertension and blood pressure (BP) above target despite polypharmacy strategies were consecutively included in this observational study. BAT was provided with the individual adaption of programmed parameters over the first months. 24-h urinary sodium excretion (UNa) was estimated at baseline and after 6 months using the Kawasaki formula in patients undergoing BAT. Additionally, the fractional sodium excretion, plasma renin activity, and aldosterone levels were assessed., Results: Forty-two patients completed the 6-month follow-up period. Office systolic and ambulatory 24-h systolic BP at baseline were 169 ± 27 mmHg and 148 ± 16 mmHg despite a median intake of 7(3-9) antihypertensive drugs. After 6 months of BAT, systolic office BP decreased to 150 ± 29 mmHg (p < 0.01), 24-h systolic BP to 142 ± 22 mmHg (p = 0.04) and 24-h UNa increased by 37% compared to baseline (128 ± 66 vs. 155 ± 83 mmol/day, p < 0.01). These findings were accompanied by a significant increase in fractional sodium excretion (0.74% [0.43-1.47] to 0.92% [0.61-1.92]; p = 0.02). However, in contrast to the significant BP reduction, eGFR, plasma sodium, renin activity and aldosterone levels did not change during BAT. The increase in sodium excretion was correlated with the change in eGFR (r = 0.371; p = 0.015)., Conclusion: The present study revealed a significant increase of estimated 24-h UNa which may contribute to the long-term BP-lowering effects of this interventional method.

Baroreflex activation therapy (BAT) is approved for the treatment of resistant hypertension. In addition to blood pressure (BP) reduction, pilot studies suggested several organoprotective effects of BAT. Thirty-two patients with resistant hypertension were prospectively treated with BAT. Besides office BP and 24-hour ambulatory BP (ABP) measurements, detection of a urinary proteome-based classifier (CKD273), which has been shown to predict chronic kidney disease (CKD) progression, was carried out at baseline and after 6 months of BAT. Office BP significantly decreased from 170 ± 25/90 ± 18 to 149 ± 29/82 ± 18 mm Hg. Analysis of CKD273 score and eGFR with CKD-EPI equation at baseline revealed strong correlation (r = 0.568, P < 0.001). After 6 months of BAT, there was no significant change in CKD273 score (-0.061 [95% CI: -0.262 to 0.140], P = 0.601). However, by stratification of the data regarding ABP response, there was a statistically significant (P = 0.0113) reduction in the CKD273 score from a mean of 0.161 [95% CI: -0.093 to 0.414] to -0.346 [95% CI: -0.632 to -0.060] after BAT in patients with systolic ABP decrease of ≥5 mm Hg. These data emphasized potential nephroprotective effects of BAT in patients with sufficient BP response., (©2018 Wiley Periodicals, Inc.)

Detection of renal artery stenosis (RAS) using Doppler is difficult to evaluate, particularly under conditions such as bilateral RAS or difficultly accessible renal arteries (RA). The objective of the present study was to assess the utility of splenic arterial compared to renal flow as an additional parameter in the Doppler evaluation of RAS. The difference between the resistive indices (RI) determined in renal and splenic parenchymal arteries (ΔRI K-S ) was evaluated in 181 hypertensive subjects without any evidence of RAS. Subsequently 47 RA in 24 patients with suspected RAS were angiographically assessed. A ΔRI K-S of 0.055 (median) was determined in the population without any evidence of RAS similar to RA with angiographically excluded stenosis (ΔRI K-S 0.068). In contrast, in angiographic proven RAS, ΔRI K-S was significantly lower (-0.050; P < .005). The assessment of the ΔRI K-S , proved to be an easily feasible parameter, which improves the diagnostic accuracy in the detection of RAS., (©2018 Wiley Periodicals, Inc.)

Background: The peptide hormone relaxin has been demonstrated to exert antifibrotic effects in renal and extrarenal tissues. The aims of this study were to identify potential anti-fibrotic effects of relaxin on human renal fibroblasts in vitro and to analyze their mechanisms., Methods: All experiments were performed in established renal fibroblast cell lines and in primary cortical fibroblasts. Effects of relaxin were analyzed on cell proliferation, apoptosis, activation of renal fibroblasts, synthesis and secretion of collagen type I and fibronectin, as well as on the secretion of matrix metalloproteinases (MMPs). Effects on transforming growth factor-beta1 (TGF-beta1) receptor binding were analyzed by flow cytometry and on TGF-beta1 signal transduction by immunoblot analyses for Smad4 and 7, translocation from cytosol to nucleus for Smad2 and 3 as well as for phosphorylated and unphosphorylated forms of p38, c-Jun NH2 terminal kinase (JNK) and extracellular-regulated protein kinase (ERK). Finally, specific siRNAs for Smad2 and 3 were applied to assess the signal transduction pathway., Results: After stimulation with relaxin, tyrosine phosphorylation of a 220 kD protein was demonstrated, indicating interaction with the receptor. Relaxin had only modest inhibitory effects on cell proliferation, and no effects on apoptosis. Conversely, relaxin exerted robust effects on TGF-beta1-induced fibroblast to myofibroblast transformation as well as on matrix synthesis and secretion even at the smallest dose tested. The secretion of MMP-2 and MMP-9 was induced noticeably by all investigated relaxin concentrations. TGF-beta1 receptor binding was not influenced by relaxin; however, it prevented Smad2 phosphorylation, translocation to nucleus, and complex formation between Smad2 and 3 indicating a possible interaction with TGF-beta1 signaling. These findings were corroborated by studies using siRNAs to Smad2 and 3 where siRNA to Smad2 but not to Smad3 inhibited the TGF-beta1 induction of fibronectin synthesis. There was no influence of relaxin on intracellular Smad3, Smad4, and Smad7 translocation or phosphorylation of mitogen-activated protein (MAP) kinases., Conclusion: Relaxin is a potent inhibitor of TGF-beta1-induced extracellular matrix (ECM) synthesis and secretion as well as fibroblast activation. Furthermore, it induces ECM degradation by induction of MMP-2 and MMP-9. These effects are mediated, at least in part, by inhibition of TGF-beta1 signaling.

Background: The multidrug resistance (MDR) gene product P-glycoprotein (P-gp) is a transmembrane efflux pump for hydrophobic, potentially toxic compounds, including the immunosuppressant cyclosporine A (CsA). We have previously shown that CsA increases P-gp expression in proximal tubule and endothelial cells in vitro. The aim of the present study was to investigate the in vivo relevance of these observations in renal allograft biopsies from CsA-treated patients., Methods: P-gp expression was determined by immunohistochemistry of paraffin sections using two different monoclonal antibodies (UIC2 and MRK16). Biopsies were taken from CsA-treated renal transplant patients with different histopathological diagnoses (N = 79) and were compared with biopsies from normal human kidneys (N = 13) or with allograft biopsies from patients under a CsA-free immunosuppression (N = 15). Moreover, biopsies from 10 donor kidneys before implantation and during rejection episodes ("zero biopsies") were investigated., Results: P-gp expression in biopsies with acute tubular necrosis (ATN; N = 10) after CsA treatment was significantly higher in arterial endothelia, proximal tubules, and epithelial cells of Bowman's capsule (BC), whereas P-gp was sparsely induced in CsA nephrotoxicity (N = 19) compared with controls. Acute cellular (N = 30) and vascular rejection (N = 10) or chronic allograft nephropathy (N = 10) after CsA was associated with strong P-gp expression in infiltrating leukocytes and increased P-gp expression in arterial endothelia, proximal tubules, and BC. In contrast, biopsies of patients treated with a CsA-free immunosuppression regimen did not show increases in P-gp expression compared with controls. Zero biopsies showed a weak, homogeneous, nonpolarized expression of P-gp in tubules and an increased expression of P-gp after CsA therapy in the brush border, arterial endothelia, and BC., Conclusions: CsA treatment was associated with increased P-gp expression in parenchymal cells of kidney transplants with ATN, acute or chronic transplant rejection, but P-gp was not increased in patients with CsA nephrotoxicity. This indicates that CsA induces its own detoxification by P-gp and that inadequate up-regulation of P-gp in renal parenchymal cells contributes to CsA nephrotoxicity. Increased expression of P-gp in infiltrating leukocytes correlated with the severity of allograft rejection, suggesting that P-gp may decrease the immunosuppressive efficacy of CsA. Thus, individual differences in the P-gp induction response of CsA-exposed renal parenchymal cells and/or infiltrating leukocytes may predispose to either CsA nephrotoxicity or rejection, respectively.