scholarly journals Endothelial Dysfunction in Chronic Kidney Disease, from Biology to Clinical Outcomes: A 2020 Update

2020 ◽  
Vol 9 (8) ◽  
pp. 2359 ◽  
Author(s):  
Stefanos Roumeliotis ◽  
Francesca Mallamaci ◽  
Carmine Zoccali

The vascular endothelium is a dynamic, functionally complex organ, modulating multiple biological processes, including vascular tone and permeability, inflammatory responses, thrombosis, and angiogenesis. Endothelial dysfunction is a threat to the integrity of the vascular system, and it is pivotal in the pathogenesis of atherosclerosis and cardiovascular disease. Reduced nitric oxide (NO) bioavailability is a hallmark of chronic kidney disease (CKD), with this disturbance being almost universal in patients who reach the most advanced phase of CKD, end-stage kidney disease (ESKD). Low NO bioavailability in CKD depends on several mechanisms affecting the expression and the activity of endothelial NO synthase (eNOS). Accumulation of endogenous inhibitors of eNOS, inflammation and oxidative stress, advanced glycosylation products (AGEs), bone mineral balance disorders encompassing hyperphosphatemia, high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23), and low levels of the active form of vitamin D (1,25 vitamin D) and the anti-ageing vasculoprotective factor Klotho all impinge upon NO bioavailability and are critical to endothelial dysfunction in CKD. Wide-ranging multivariate interventions are needed to counter endothelial dysfunction in CKD, an alteration triggering arterial disease and cardiovascular complications in this high-risk population.

Author(s):  
Anne Schön ◽  
Maren Leifheit-Nestler ◽  
Jennifer Deppe ◽  
Dagmar-Christiane Fischer ◽  
Aysun K Bayazit ◽  
...  

Abstract Background Uraemic cardiac remodelling is associated with vitamin D and Klotho deficiency, elevated fibroblast growth factor 23 (FGF23) and activation of the renin–angiotensin system (RAS). The cardioprotective properties of active vitamin D analogues in this setting are unclear. Methods In rats with 5/6 nephrectomy (5/6Nx) treated with calcitriol, the cardiac phenotype and local RAS activation were investigated compared with controls. A nested case–control study was performed within the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study, including children with chronic kidney disease (CKD) Stages 3–5 [estimated glomerular filtration rate (eGFR) 25 mL/min/1.73 m2] treated with and without active vitamin D. Echocardiograms, plasma FGF23 and soluble Klotho (sKlotho) were assessed at baseline and after 9 months. Results In rats with 5/6Nx, left ventricular (LV) hypertrophy, LV fibrosis and upregulated cardiac RAS were dose-dependently attenuated by calcitriol. Calcitriol further stimulated FGF23 synthesis in bone but not in the heart, and normalized suppressed renal Klotho expression. In the 4C study cohort, treatment over a mean period of 9 months with active vitamin D was associated with increased FGF23 and phosphate and decreased sKlotho and eGFR compared with vitamin D naïve controls, whereas LV mass index did not differ between groups. Conclusions Active vitamin D ameliorates cardiac remodelling and normalizes renal Klotho expression in 5/6Nx rats but does not improve the cardiac phenotype in children with CKD Stages 3–5. This discrepancy may be due to further enhancement of circulating FGF23 and faster progression of CKD associated with reduced sKlotho and higher serum phosphate in vitamin D-treated patients.


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Kenichi Akiyama ◽  
Takaaki Kimura ◽  
Kazuhiro Shiizaki

Calciprotein particles (CPPs) are a new biological marker of chronic kidney disease-mineral and bone disorder (CKD-MBD). CPPs consist of phosphate, calcium, and some proteins, with phosphate being the major contributor to the level and biological activity of CPPs. Recent studies have shown the physiological and pathological significance of CPPs, including contributions to bone and mineral metabolism, and to tissue and organ impairments such as cardiovascular damage and inflammatory responses. These actions are well known as important aspects of CKD-MBD. Fibroblast growth factor 23 (FGF23), which is secreted from the bone as the phosphaturic hormone, is markedly elevated in CKD-MBD. Many clinical studies have shown significant relationships between the level of FGF23 and outcomes such as mortality, prevalence of cardiovascular disease, bone fracture, and levels of inflammatory markers. Basic and clinical studies have suggested that CPPs contribute to synthesis and secretion of FGF23. Surgical treatments such as renal transplantation and parathyroidectomy for patients with CKD-MBD suppress excess levels of phosphate, calcium, parathyroid hormone (PTH), and FGF23, which are related to the CPP level. Therefore, suppression of CPPs might also contribute to improved clinical outcomes after these treatments.


2018 ◽  
Vol 315 (5) ◽  
pp. H1414-H1424 ◽  
Author(s):  
Melissa Verkaik ◽  
Rio P. Juni ◽  
Ellen P. M. van Loon ◽  
Erik M. van Poelgeest ◽  
Rick F. J. Kwekkeboom ◽  
...  

Cardiovascular diseases account for ~50% of mortality in patients with chronic kidney disease (CKD). Fibroblast growth factor 23 (FGF23) is independently associated with endothelial dysfunction and cardiovascular mortality. We hypothesized that CKD impairs microvascular endothelial function and that this can be attributed to FGF23. Mice were subjected to partial nephrectomy (5/6Nx) or sham surgery. To evaluate the functional role of FGF23, non-CKD mice received FGF23 injections and CKD mice received FGF23-blocking antibodies after 5/6Nx surgery. To examine microvascular function, myocardial perfusion in vivo and vascular function of gracilis resistance arteries ex vivo were assessed in mice. 5/6Nx surgery blunted ex vivo vasodilator responses to acetylcholine, whereas responses to sodium nitroprusside or endothelin were normal. In vivo FGF23 injections in non-CKD mice mimicked this endothelial defect, and FGF23 antibodies in 5/6Nx mice prevented endothelial dysfunction. Stimulation of microvascular endothelial cells with FGF23 in vitro did not induce ERK phosphorylation. Increased plasma asymmetric dimethylarginine concentrations were increased by FGF23 and strongly correlated with endothelial dysfunction. Increased FGF23 concentration did not mimic impaired endothelial function in the myocardium of 5/6Nx mice. In conclusion, impaired peripheral endothelium-dependent vasodilatation in 5/6Nx mice is mediated by FGF23 and can be prevented by blocking FGF23. These data corroborate FGF23 as an important target to combat cardiovascular disease in CKD.NEW & NOTEWORTHY In the present study, we provide the first evidence that fibroblast growth factor 23 (FGF23) is a cause of peripheral endothelial dysfunction in a model of early chronic kidney disease (CKD) and that endothelial dysfunction in CKD can be prevented by blockade of FGF23. This pathological effect on endothelial cells was induced by long-term exposure of physiological levels of FGF23. Mechanistically, increased plasma asymmetric dimethylarginine concentrations were strongly associated with this endothelial dysfunction in CKD and were increased by FGF23.


Author(s):  
Alexandra Voinescu ◽  
Nadia Wasi Iqbal ◽  
Kevin J. Martin

Chronic kidney disease is associated with the inability to control normal mineral homeostasis, resulting in abnormalities in serum levels of calcium, phosphorus, parathyroid hormone, fibroblast growth factor 23 (FGF23) and vitamin D metabolism. These disturbances lead to the development of secondary hyperparathyroidism, skeletal abnormalities, vascular calcifications, and other systemic manifestations. Traditionally, mineral and bone abnormalities seen in chronic kidney disease were included in the term ‘renal osteodystrophy’. More recently, the term chronic kidney disease-mineral and bone disorder was introduced to define the biochemical abnormalities of phosphorus, parathyroid hormone, FGF23, calcium, or vitamin D metabolism, abnormalities in bone remodelling and mineralization, and vascular or other soft tissue calcifications.


Author(s):  
Marilena Christodoulou ◽  
Terence J. Aspray ◽  
Inez Schoenmakers

AbstractA large proportion of patients with chronic kidney disease (CKD) are vitamin D deficient (plasma 25-hydroxyvitamin D (25(OH)D) < 25 or 30 nmol/L per UK and US population guidelines) and this contributes to the development of CKD–mineral bone disease (CKD–MBD). Gaps in the evidence-base for the management of vitamin D status in relation to CKD–MBD are hindering the formulation of comprehensive guidelines. We conducted a systemic review of 22 RCTs with different forms of vitamin D or analogues with CKD–MBD related outcomes and meta-analyses for parathyroid hormone (PTH). We provide a comprehensive overview of current guidelines for the management of vitamin D status for pre-dialysis CKD patients. Vitamin D supplementation had an inconsistent effect on PTH concentrations and meta-analysis showed non- significant reduction (P = 0.08) whereas calcifediol, calcitriol and paricalcitol consistently reduced PTH. An increase in Fibroblast Growth Factor 23 (FGF23) with analogue administration was found in all 3 studies reporting FGF23, but was unaltered in 4 studies with vitamin D or calcifediol. Few RCTS reported markers of bone metabolism and variations in the range of markers prevented direct comparisons. Guidelines for CKD stages G1–G3a follow general population recommendations. For the correction of deficiency general or CKD-specific patient guidelines provide recommendations. Calcitriol or analogues administration is restricted to stages G3b–G5 and depends on patient characteristics. In conclusion, the effect of vitamin D supplementation in CKD patients was inconsistent between studies. Calcifediol and analogues consistently suppressed PTH, but the increase in FGF23 with calcitriol analogues warrants caution.


2018 ◽  
Vol 50 (5) ◽  
pp. 923-927 ◽  
Author(s):  
Qingyan Zhang ◽  
Miao Zhang ◽  
Hengjin Wang ◽  
Cheng Sun ◽  
Yuan Feng ◽  
...  

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