Effect of secondary hyperparathyroidism serum on endothelial cells and intervention with Klotho

Abstract

The aim of the present study was to investigate the effect of the serum of patients with secondary hyperparathyroidism (SHPT) on endothelial cells and to examine the protective effect and the possible mechanism of Klotho. A total of three types of mixed serum from 15 patients with SHPT scheduled for parathyroidectomy, 10 chronic kidney disease (CKD) patients at stage 5 without SHPT and 15 healthy volunteers were collected. Initially, human umbilical vein endothelial cells (HUVECs) were incubated in vitro with the three types of serum and levels of proliferation were compared by assessing viable cell numbers with cell counting kit-8 (CCK-8). Subsequently, HUVECs were divided into three groups: Control group (healthy serum medium), SHPT group (SHPT serum) and Klotho treatment group (SHPT serum and Klotho). The proliferative and apoptotic levels of endothelial cells were evaluated by CCK-8 and flow cytometry, respectively. The levels of extracellular signal-regulated kinase (ERK1/2) and phosphorylated forms of ERK1/2 (p-ERK1/2) were detected using western blotting (with or without ERK1/2 inhibitor PD98059). The synthesis of nitric oxide (NO) was measured using the nitrate reduction method. The proliferation of HUVECs was inhibited by the serum from SHPT patients and CKD-5 patients without SHPT and the inhibitory effects of the SHPT serum were the most marked (P<0.05). Inhibition of HUVEC proliferation by SHPT serum occurred in a concentration-dependent manner within a specific range (5-20%; P<0.05) and also in a time-dependent manner within 6-24 h. Proliferation was partly restored and apoptosis was inhibited when 50-100 ng/ml Klotho was added into 10% SHPT serum (P<0.05). At the same time, the expression of p-ERK1/2 was upregulated, which may be inhibited by PD98059. The synthesis of NO was decreased in the SHPT group (P<0.05) and increased following treatment with Klotho (P<0.05). The results of the present study indicated that the proliferation of HUVECs was inhibited by the serum from SHPT patients. Klotho may partly antagonize this effect due to its inhibition of HUVEC apoptosis and upregulation of p-ERK1/2.

Monocrotaline-Induced Pulmonary Hypertension Involves Downregulation of Antiaging Protein Klotho and eNOS Activity

“…18–19 Klotho gene mutation causes lung inflammation and emphysema, 19 while unmutated Klotho has been shown to reduce inflammation and oxidative stress in kidneys. 19–21 Secreted Klotho (SKL) was reported to protect against endothelial dysfunction 22–23 and endothelial cell (EC) apoptosis 24 and attenuate vascular remodeling associated with systemic hypertension. 23 Mesenchymal stem cells entail have secretory function.…”

Effects of Normal Reference Range of Phosphorus and Corresponding PTH on Endothelial Function in CKD Patients

“…Regarding iPTH, in vivo study showed chronic renal insufficiency is associated with reduced endothelial nitric oxide synthase expression and reduced NO generation, an effect that is reversed by parathyroidectomy ( 35 ). Another in vitro study investigated the effect of high levels of iPTH on the proliferation of endothelial cells using the serum of 15 patients with secondary hyperparathyroidism (SHPT), 10 patients with CKD 5 without SHPT, and 15 healthy volunteers ( 36 ). The study found that the proliferation of human umbilical vein endothelial cells was inhibited by the serum obtained from SHPT patients and CKD 5 patients without SHPT, and the inhibitory effects of the SHPT serum were the most marked when the synthesis of NO was significantly decreased.…”

The role of AMP‐activated protein kinase α1‐mediated endoplasmic reticulum stress in alleviating the toxic effect of uremic toxin indoxyl sulfate on vascular endothelial cells by Klotho

“…The overexpression of Klotho also inhibits TGF‐β‐induced myocardial fibrosis (Liu et al, 2019 ). Our previous studies have shown that the recombinant Klotho can antagonize the toxic effects of serum from CKD patients with secondary hyperparathyroidism on vascular endothelial cells (Chen, Mao, Yu, et al, 2015 ) and can alleviate vascular smooth muscle cell calcification induced by β‐glycerophosphoric acid (Chen et al, 2015 ). Studies on the expression of Klotho in the cardiovascular system are not consistent (Corsetti et al, 2016 ; Fang et al, 2014 ; Jimbo et al, 2014 ; Lindberg et al, 2013 ; Scialla et al, 2013 ).…”

“…The phenotype of Kl gene knockout mice is very similar to the clinical manifestations of CKD, suggesting that CKD might be a state of Kl gene deficiency (Hu, Kuro‐o, & Moe, 2013 ), and anti‐aging treatment may be a new approach for delaying CKD and the development of its complications (Kooman et al, 2013 ). Our previous study has shown that supplementation of exogenous Klotho protein (Klotho) protects vascular endothelial cells from uremia serum (Chen et al, 2015 ). However, the mechanisms remain to be elucidated.…”