scholarly journals Uremic Vascular Calcification: The Pathogenic Roles and Gastrointestinal Decontamination of Uremic Toxins

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 812
Author(s):  
Chia-Ter Chao ◽  
Shih-Hua Lin

Uremic vascular calcification (VC) commonly occurs during advanced chronic kidney disease (CKD) and significantly increases cardiovascular morbidity and mortality. Uremic toxins are integral within VC pathogenesis, as they exhibit adverse vascular influences ranging from atherosclerosis, vascular inflammation, to VC. Experimental removal of these toxins, including small molecular (phosphate, trimethylamine-N-oxide), large molecular (fibroblast growth factor-23, cytokines), and protein-bound ones (indoxyl sulfate, p-cresyl sulfate), ameliorates VC. As most uremic toxins share a gut origin, interventions through gastrointestinal tract are expected to demonstrate particular efficacy. The “gastrointestinal decontamination” through the removal of toxin in situ or impediment of toxin absorption within the gastrointestinal tract is a practical and potential strategy to reduce uremic toxins. First and foremost, the modulation of gut microbiota through optimizing dietary composition, the use of prebiotics or probiotics, can be implemented. Other promising strategies such as reducing calcium load, minimizing intestinal phosphate absorption through the optimization of phosphate binders and the inhibition of gut luminal phosphate transporters, the administration of magnesium, and the use of oral toxin adsorbent for protein-bound uremic toxins may potentially counteract uremic VC. Novel agents such as tenapanor have been actively tested in clinical trials for their potential vascular benefits. Further advanced studies are still warranted to validate the beneficial effects of gastrointestinal decontamination in the retardation and treatment of uremic VC.

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 737 ◽  
Author(s):  
Hyun-Joo Park ◽  
Yeon Kim ◽  
Mi-Kyoung Kim ◽  
Jae Joon Hwang ◽  
Hyung Joon Kim ◽  
...  

Vascular calcification is the pathological deposition of calcium/phosphate in the vascular system and is closely associated with cardiovascular morbidity and mortality. Here, we investigated the role of gastrin-releasing peptide (GRP) in phosphate-induced vascular calcification and its potential regulatory mechanism. We found that the silencing of GRP gene and treatment with the GRP receptor antagonist, RC-3095, attenuated the inorganic phosphate-induced calcification of vascular smooth muscle cells (VSMCs). This attenuation was caused by inhibiting phenotype change, apoptosis and matrix vesicle release in VSMCs. Moreover, the treatment with RC-3095 effectively ameliorated phosphate-induced calcium deposition in rat aortas ex vivo and aortas of chronic kidney disease in mice in vivo. Therefore, the regulation of the GRP-GRP receptor axis may be a potential strategy for treatment of diseases associated with excessive vascular calcification.


2021 ◽  
Vol 135 (1) ◽  
pp. 201-227
Author(s):  
Jakob Voelkl ◽  
Daniela Egli-Spichtig ◽  
Ioana Alesutan ◽  
Carsten A. Wagner

Abstract Dietary habits in the western world lead to increasing phosphate intake. Under physiological conditions, extraosseous precipitation of phosphate with calcium is prevented by a mineral buffering system composed of calcification inhibitors and tight control of serum phosphate levels. The coordinated hormonal regulation of serum phosphate involves fibroblast growth factor 23 (FGF23), αKlotho, parathyroid hormone (PTH) and calcitriol. A severe derangement of phosphate homeostasis is observed in patients with chronic kidney disease (CKD), a patient collective with extremely high risk of cardiovascular morbidity and mortality. Higher phosphate levels in serum have been associated with increased risk for cardiovascular disease (CVD) in CKD patients, but also in the general population. The causal connections between phosphate and CVD are currently incompletely understood. An assumed link between phosphate and cardiovascular risk is the development of medial vascular calcification, a process actively promoted and regulated by a complex mechanistic interplay involving activation of pro-inflammatory signalling. Emerging evidence indicates a link between disturbances in phosphate homeostasis and inflammation. The present review focuses on critical interactions of phosphate homeostasis, inflammation, vascular calcification and CVD. Especially, pro-inflammatory responses mediating hyperphosphatemia-related development of vascular calcification as well as FGF23 as a critical factor in the interplay between inflammation and cardiovascular alterations, beyond its phosphaturic effects, are addressed.


Toxins ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 624 ◽  
Author(s):  
Nikolas Rapp ◽  
Pieter Evenepoel ◽  
Peter Stenvinkel ◽  
Leon Schurgers

The cardiorenal syndrome relates to the detrimental interplay between the vascular system and the kidney. The uremic milieu induced by reduced kidney function alters the phenotype of vascular smooth muscle cells (VSMC) and promotes vascular calcification, a condition which is strongly linked to cardiovascular morbidity and mortality. Biological mechanisms involved include generation of reactive oxygen species, inflammation and accelerated senescence. A better understanding of the vasotoxic effects of uremic retention molecules may reveal novel avenues to reduce vascular calcification in CKD. The present review aims to present a state of the art on the role of uremic toxins in pathogenesis of vascular calcification. Evidence, so far, is fragmentary and limited with only a few uremic toxins being investigated, often by a single group of investigators. Experimental heterogeneity furthermore hampers comparison. There is a clear need for a concerted action harmonizing and standardizing experimental protocols and combining efforts of basic and clinical researchers to solve the complex puzzle of uremic vascular calcification.


2020 ◽  
Vol 16 (6) ◽  
pp. 891-899 ◽  
Author(s):  
Wissam Zam

Probiotics are viable microorganisms widely used for their claimed beneficial effects on the host health. A wide number of researchers proved that the intake of probiotic bacteria has numerous health benefits which created a big market of probiotic foods worldwide. The biggest challenge in the development of these products is to maintain the viability of bacterial cells during the storage of the product as well as throughout the gastrointestinal tract transit after consumption, so that the claimed health benefits can be delivered to the consumer. Different approaches have been proposed for increasing the resistance of these sensitive microorganisms, including the selection of resistant strains, incorporation of micronutrients, and most recently the use of microencapsulation techniques. Microencapsulation has resulted in enhancing the viability of these microorganisms which allows its wide use in the food industry. In this review, the most common techniques used for microencapsulation of probiotics will be presented, as well as the most usual microcapsule shell materials.


Author(s):  
John R Burnett ◽  
Samuel D Vasikaran

Atherosclerotic heart disease and osteoporosis are both diseases of old age. Evidence is accumulating for a link between vascular and bone disease. Calcification is a common feature of atherosclerotic plaques, and osteoporosis is associated with both atherosclerosis and vascular calcification. However, the relationship of vascular calcification to the pathogenesis of atherosclerosis remains incompletely understood. Hormone replacement therapy has beneficial effects in the prevention of both atherosclerosis and osteoporosis. Bisphosphonates inhibit bone resorption and are used in the treatment of osteoporosis, whereas the statins inhibit cholesterol biosynthesis and are used for the treatment of atherosclerosis. We have reviewed recent advances in the knowledge of the actions of bisphosphonates and statins at the cellular, molecular and end-organ levels in order to examine the relationship between cardiovascular disease and osteoporosis and to explore the link between lipids and bones. These studies suggest that the mechanism of actions of these two classes of drugs at the cellular level may not be mutually exclusive. There are some early clinical data to complement these findings, suggesting that statins increase bone density and bisphosphonates may have a beneficial effect in vivo on plasma lipid levels and on the atherosclerotic process. Properly designed prospective studies that examine the effect of statins on bone density and fractures, as well as the effects of bisphosphonates on lipid profiles, atherosclerotic progression and cardiovascular morbidity and mortality are needed to define clearly the clinical effects and potential new roles for these agents.


Dose-Response ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 155932582098216
Author(s):  
Bing Wang ◽  
Kaoru Tanaka ◽  
Takanori Katsube ◽  
Kouichi Maruyama ◽  
Yasuharu Ninomiya ◽  
...  

Radioadaptive response (RAR) describes a phenomenon in a variety of in vitro and in vivo systems that a low-dose of priming ionizing radiation (IR) reduces detrimental effects of a subsequent challenge IR at higher doses. Among in vivo investigations, studies using the mouse RAR model (Yonezawa Effect) showed that RAR could significantly extenuate high-dose IR-induced detrimental effects such as decrease of hematopoietic stem cells and progenitor cells, acute radiation hematopoietic syndrome, genotoxicity and genomic instability. Meanwhile, it has been demonstrated that diet intervention has a great impact on health, and dietary restriction shows beneficial effects on numerous diseases in animal models. In this work, by using the mouse RAR model and mild dietary restriction (MDR), we confirmed that combination of RAR and MDR could more efficiently reduce radiogenotoxic damage without significant change of the RAR phenotype. These findings suggested that MDR may share some common pathways with RAR to activate mechanisms consequently resulting in suppression of genotoxicity. As MDR could also increase resistance to chemotherapy and radiotherapy in normal cells, we propose that combination of MDR, RAR, and other cancer treatments (i.e., chemotherapy and radiotherapy) represent a potential strategy to increase the treatment efficacy and prevent IR risk in humans.


2011 ◽  
Vol 301 (5) ◽  
pp. F1105-F1113 ◽  
Author(s):  
Akiko Ohi ◽  
Etsuyo Hanabusa ◽  
Otoya Ueda ◽  
Hiroko Segawa ◽  
Naoshi Horiba ◽  
...  

An inorganic phosphate (Pi)-restricted diet is important for patients with chronic kidney disease and patients on hemodialysis. Phosphate binders are essential for preventing hyperphosphatemia and ectopic calcification. The sodium-dependent Pi (Na/Pi) transport system is involved in intestinal Pi absorption and is regulated by several factors. The type II sodium-dependent Pi transporter Npt2b is expressed in the brush-border membrane in intestinal epithelial cells and transports Pi. In the present study, we analyzed the phenotype of Npt2b−/− and hetero+/− mice. Npt2b−/− mice died in utero soon after implantation, indicating that Npt2b is essential for early embryonic development. At 4 wk of age, Npt2b+/− mice showed hypophosphatemia and low urinary Pi excretion. Plasma fibroblast growth factor 23 levels were significantly decreased and 1,25(OH)2D3 levels were significantly increased in Npt2b+/− mice compared with Npt2b+/+ mice. Npt2b mRNA levels were reduced to 50% that in Npt2b+/+ mice. In contrast, renal Npt2a and Npt2c transporter protein levels were significantly increased in Npt2b+/− mice. At 20 wk of age, Npt2b+/− mice showed hypophosphaturia and reduced Na/Pi cotransport activity in the distal intestine. Npt2b+/+ mice with adenine-induced renal failure had hyperphosphatemia and high plasma creatinine levels. Npt2b+/− mice treated with adenine had significantly reduced plasma Pi levels compared with Npt2b+/+ mice. Intestinal Npt2b protein and Na+/Pi transport activity levels were significantly lower in Npt2b+/− mice than in the Npt2b+/+ mice. The findings of the present studies suggest that Npt2b is an important target for the prevention of hyperphosphatemia.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Takehisa Shimizu ◽  
Toru Tanaka ◽  
Tatsuya Iso ◽  
Masahiko Kurabayashi

Vascular calcification is a prominent feature of atherosclerosis and closely correlated with cardiovascular morbidity and mortality. In this study, we hypothesize that Notch signaling plays an important role in osteogenic conversion of smooth muscle cells (SMCs) and vascular calcification. <Methods and Results> Either Notch ligand-expressing cells or overexpression of Notch intracellular domains (NICDs) induced expression of Msx2, a key regulator of osteogenic conversion, in human aortic SMCs (HASMCs). In addition, overexpression of Notch1 intracellular domain (N1-ICD) markedly upregulated alkaline phosphatase (ALP) activity and matrix mineralization of HASMCs. A knockdown experiment with a small interfering RNA confirmed that Msx2, but not Runx2/Cbfa1, another key osteogenic transcription factor, is responsible for Notch1-induced osteogenic conversion of HASMCs. Furthermore, this Notch1-Msx2 pathway was independent of bone morphogenetic protein-2 (BMP-2), an osteogenic morphogen upstream of Msx2. The transcriptional activity of the Msx2 promoter was significantly enhanced by Notch ligands stimulation, whereas it was abrogated by a specific Notch signaling inhibitor. The RBP-Jk binding element within the Msx2 promoter was critical to Notch1-induced Msx2 gene expression, and correspondingly, neither N1-ICD overexpression nor Notch ligands stimulation increase the Msx2 expression or transcriptional activity of the Msx2 promoter, respectively, in RBP-Jk-deficient fibroblasts. Immunohistochemistry of human artery specimens revealed colocalization of Notch1 and Msx2 within atherosclerotic plaques, indicating a role of Notch1-Msx2 pathway in vascular calcification in vivo. These results suggest that Notch signaling directly targets Msx2, thus accelerating osteogenic conversion of HASMCs and, as a result, a formation of vascular calcification.


Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2070
Author(s):  
Pasquale Esposito ◽  
Daniela Verzola ◽  
Daniela Picciotto ◽  
Leda Cipriani ◽  
Francesca Viazzi ◽  
...  

A current hypothesis is that transforming growth factor-β signaling ligands, such as activin-A and myostatin, play a role in vascular damage in atherosclerosis and chronic kidney disease (CKD). Myostatin and activin-A bind with different affinity the activin receptors (type I or II), activating distinct intracellular signaling pathways and finally leading to modulation of gene expression. Myostatin and activin-A are expressed by different cell types and tissues, including muscle, kidney, reproductive system, immune cells, heart, and vessels, where they exert pleiotropic effects. In arterial vessels, experimental evidence indicates that myostatin may mostly promote vascular inflammation and premature aging, while activin-A is involved in the pathogenesis of vascular calcification and CKD-related mineral bone disorders. In this review, we discuss novel insights into the biology and physiology of the role played by myostatin and activin in the vascular wall, focusing on the experimental and clinical data, which suggest the involvement of these molecules in vascular remodeling and calcification processes. Moreover, we describe the strategies that have been used to modulate the activin downward signal. Understanding the role of myostatin/activin signaling in vascular disease and bone metabolism may provide novel therapeutic opportunities to improve the treatment of conditions still associated with high morbidity and mortality.


Sign in / Sign up

Export Citation Format

Share Document