MO053INHIBITION OF SODIUM PHOSPHATE TRANSPORTER NPT2A IMPROVES EXPERIMENTAL VASCULAR CALCIFICATION AND PHOSPHATE HOMEOSTASIS IN RATS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Juergen Klar ◽  
Giese Anja ◽  
Alexander Ehrmann ◽  
Christoph Thiel ◽  
Bernd Riedl ◽  
...  
Keyword(s):  
Vascular Calcification ◽  
Plasma Levels ◽  
Calcium Content ◽  
Treated Group ◽  
Phosphate Transporter ◽  
Phosphate Homeostasis ◽  
Simultaneous Treatment ◽  
Phosphate Excretion ◽  
Male Wistar Rats ◽  
Fgf 23

Abstract Background and Aims A dysregulated phosphate homeostasis is strongly associated with mortality, cardiovascular events and vascular calcification, particularly in patients suffering from CKD. Inhibition of the tubular phosphate transporter Npt2a provides a novel and unique mechanism to address phosphate homeostasis imbalance and vascular calcification. Method Npt2a activity was measured in a cell-based assay, using a stable CHO cell line with inducible Npt2a expression. Male Wistar rats were used for all experiments. Healthy rats were treated orally with BAY 767, a potent Npt2a inhibitor developed at Bayer AG to assess urinary phosphate excretion. Vascular calcification was induced by administration of a pan-FGFR inh. (25mg/kg) for 10 days. Calcium content in the aorta was measured as surrogate for vascular calcification. Blood samples were withdrawn at the end of the study to determine the plasma levels of FGF-23, parathyroid hormone and phosphate with commercially available assay systems according to the manufactures protocols (FGF-23 and PTH: ELISA Kit, Immuntopics; phosphate: Pentra400 system). Results BAY 767 was identified as potent Npt2a inhibitor, with an IC50 of 2.9/6 nM on rat/ human Npt2a, respectively, selective over Npt2b, Npt2c and Pit-1. Single dose treatments of healthy rats resulted in a significant, dose-dependent increase in urinary phosphate excretion within 16h. In an experimental vascular calcification model, massive vascular calcification and hyperphosphatemia was induced by daily oral administration of a FGFR inh. Simultaneous treatment with the Npt2a inhibitor BAY 767 significantly inhibited vascular calcification in comparison to untreated rats. In this set-up the plasma phosphate level was increased after 10 days up to 3.7 mmol/L in the FGFR inh. treated group compared to 1.9 mmol/L in control animals, whilst treatment with BAY 767 reduced plasma levels to 2.7 mmol/L. In addition, FGF-23 and PTH were also reduced under compound BAY 767 treatment. However, in the same model 2.2% lanthanum carbonate was not beneficial with respect to vascular calcification. Conclusion Our results show for the first time that treatment with a Npt2a inhibitor improves vascular calcification by addressing urinary phosphate excretion and phosphate homeostasis in rats. Npt2a inhibition may provide a new therapeutic principle for patients suffering from disbalanced phosphate homeostasis and vascular calcifications, including CKD patients.

scholarly journals P1098THE CHANGE OF PLASMA SCLEROSTIN AND OTHER BIOMARKERS IN HEMODIALYTIC PATIENTS USING DIALYZER WITH MEDIUM CUT-OFF MEMBRANE

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Jong Hwan Jung ◽  
Seon-Ho Ahn ◽  
Ju Hung Song
Keyword(s):  
Molecular Weight ◽  
Vascular Calcification ◽  
Plasma Levels ◽  
Cardiovascular Complications ◽  
Uremic Toxins ◽  
Control Group ◽  
High Flux ◽  
Middle Molecules ◽  
Significant Difference ◽  
Fgf 23

Abstract Background and Aims Protein-bound toxins and uremic toxins with middle molecular weight usually develop uremic symptoms in patients with advanced chronic kidney disease (CKD) or end-stage renal disease (ESRD). Although the effect on uremic toxicity of the molecules is not proven yet, middle molecules or larger middle molecules is regarded with important substance concerning of development of uremic symptoms and cardiovascular complication, particularly in CKD patients. Hemodialysis (HD) or hemodiafiltration (HDF) using dialyzer with high flux membrane provided improved clearance for uremic toxins with middle molecular weights. However, uremic toxins with larger middle molecular weight could not be easily removed through above methods. Medium cut-off (MCO) membrane can remove larger middle molecules which can be not removed through high flux membrane and HDF. From this perspective, chronic use of MCO membrane lowering the plasma concentration of larger middle molecules associated with cardiovascular complications including vascular calcification may give beneficial effect, particularly in patients with ESRD. Method Twenty-five patients undergoing chronic hemodialysis were prospectively analyzed for 6 months. We randomly divided enrolled patients into two groups: control group and MCO group. Patients in the control group used dialyzer with high flux membrane and patients in MCO group used dialyzer with MCO membrane. The enrolled patients performed hemodialysis thrice a week during 6 months. We measured plasma levels of several biomarkers at baseline and 3-month and 6-month through the multiplexing using Luminex® technology. In this prospective study, we performed comparative analysis with larger middle molecules, such as CXCL16, sclerostin, and FGF-23, in both groups. Results The plasma levels of all biomarkers at baseline did not show significant difference between two groups (CXCL16: p =0.904, Sclerostin: p =0.322, FGF-23: p =0.065, respectively). However, plasma sclerostin levels at 3-month and 6-month were significantly lower in MCO group (p = 0.060, p <0.005, respectively). In addition, even after analysis of covariance through ANCOVA analysis, plasma sclerostin levels at 3-month and 6-month were significantly lower in MCO group compared with the control group (p = 0.042, p =0.001, respectively). But, there was no a significant decrease of plasma sclerostin levels according to time, particularly in MCO group (p = 0.157, p =0.412, respectively) (Figure 1). Conclusion This study showed the 6-month outcome for changes of the plasma levels of larger middle molecules, including CXCL16, sclerostin, and FGF-23, particularly in dialytic patients using dialyzer with MCO membrane. Plasma sclerostin associated with vascular calcification showed decreasing tendency during 6 months after application of MCO membrane, but, there was no statistical significance. However, plasma levels of sclerostin were significantly lower in dialytic patients using MCO membrane than those using high flux membrane at 3 and 6 months, respectively. Therefore, hemodialysis using dialyzer with MCO membrane may be an option to attenuate cardiovascular complications in ESRD patients.

P1237TISSUE-NONSPECIFIC ALKALINE PHOSPHATASE, A CULPRIT DURING ARTERIAL MEDIA CALCIFICATION BUT INDISPENSABLE DURING PHYSIOLOGICAL BONE FORMATION/-MINERALIZATION IN RATS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Britt Opdebeeck ◽  
José Millan Luis ◽  
Anthony Pinkerton ◽  
Anja Verhulst ◽  
Patrick D'Haese ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Bone Formation ◽  
Vascular Calcification ◽  
Rat Model ◽  
Bone Mineralization ◽  
Calcium Content ◽  
Marker Genes ◽  
Peripheral Arteries ◽  
Calcium Phosphorus ◽  
Chondrogenic Marker

Abstract Background and Aims Vascular media calcification is frequently seen in elderly and patients with chronic kidney disease (CKD), diabetes and osteoporosis. Pyrophosphate is a well-known calcification inhibitor that binds to nascent hydroxyapatite crystals and prevents further incorporation of inorganic phosphate into these crystals. However, the enzyme tissue-nonspecific alkaline phosphatase (TNAP), which is highly expressed in calcified arteries, degrades extracellular pyrophosphate into phosphate ions, by which pyrophosphate loses its ability to block vascular calcification. Here, we aimed to evaluate whether a TNAP inhibitor is able to prevent the development of arterial calcification in a rat model of warfarin-induced vascular calcification. Method To induce vascular calcification, rats received a diet containing 0.30% warfarin and 0.15% vitamin K1 throughout the entire study and were subjected to the following daily treatments: (i) vehicle (n=10) or (ii) 10 mg/kg/day TNAP-inhibitor (n=10) administered via an intraperitoneal catheter from start of the study until sacrifice at week 7. Calcium, phosphorus and parathyroid hormone (PTH) levels were determined in serum samples as these are important determinants of vascular calcification. As TNAP is also expressed in the liver, serum alanine aminotransferase (ALT) and aspartate (AST) levels were analyzed. At sacrifice, vascular calcification was evaluated by measurement of the total calcium content in the arteries and quantification of the area % calcification on Von Kossa stained sections of the aorta. The mRNA expression of osteo/chondrogenic marker genes (runx2, TNAP, SOX9, collagen 1 and collagen 2) was analyzed in the aorta by qPCR to verify whether vascular smooth muscle cells underwent reprogramming towards bone-like cells. Bone histomorphometry was performed on the left tibia to measure static and dynamic bone parameters as TNAP also regulates physiological bone mineralization. Results No differences in serum calcium, phosphorus and PTH levels was observed between both study groups. Warfarin exposure resulted in distinct calcification in the aorta and peripheral arteries. Daily dosing with the TNAP inhibitor (10 mg/kg/day) for 7 weeks significantly reduced vascular calcification as indicated by a significant decrease in calcium content in the aorta (vehicle 3.84±0.64 mg calcium/g wet tissue vs TNAP inhibitor 0.70±0.23 mg calcium/g wet tissue) and peripheral arteries and a distinct reduction in area % calcification on Von Kossa stained aortic sections as compared to vehicle condition. The inhibitory effects of SBI-425 on vascular calcification were without altering serum liver markers ALT and AST levels. Furthermore, TNAP-inhibitor SBI-425 did not modulate the mRNA expression of osteo/chondrogenic marker genes runx2, TNAP, SOX9, collagen 1 and 2. Dosing with SBI-425 resulted in decreased bone formation rate and mineral apposition rate, and increased osteoid maturation time and this without significant changes in osteoclast- and eroded perimeter. Conclusion Dosing with TNAP inhibitor SBI-425 significantly reduced the calcification in the aorta and peripheral arteries of a rat model of warfarin-induced vascular calcification and this without affecting liver function. However, suppression of TNAP activity should be limited in order to maintain adequate physiological bone mineralization.

scholarly journals Influence of Lactate Accumulation on Calcium Content of Ischemic and Postischemic Brain

1989 ◽  
Vol 9 (5) ◽  
pp. 640-645 ◽  
Author(s):  
V. MacMillan
Keyword(s):  
Carotid Arteries ◽  
Calcium Content ◽  
Treated Group ◽  
Sampling Time ◽  
Early Event ◽  
Lactate Accumulation ◽  
Vertebral Arteries ◽  
Eeg Abnormalities ◽  
Tissue Calcium

In this study, the cerebral hemisphere content of calcium as well as selected parameters of oxidative metabolism and electrophysiological function were assessed in normoglycemic and hyperglycemic rats that were exposed to ischemia produced by electrocautery of the vertebral arteries and reversible occlusion of the carotid arteries. In hyperglycemic animals, 0.5 h of ischemia was associated with large accumulations of lactate (27 mmol/kg), whereas normoglycemic animals showed lesser lactate accumulation (17 mmol/kg). At this sampling time (0.5 h of ischemia), both groups of ischemic animals showed tissue calcium contents that were unchanged from preischemic control levels. In normoglycemic animals, release of the carotid clamps and recirculation for 1.5–24 h was associated with normalization of lactate, ATP and phosphocreatine, clinical behavior, and EEC During this 24 h of recirculation, cerebral calcium levels showed no changes. Hyperglycemic ischemic animals recirculated for 1.5–24 h showed a persistent lactic acidosis, depressed ATP and phosphocreatine, gross EEG abnormalities, seizures, and a high mortality rate. Again, during this 24 h period, cerebral calcium content showed no changes from preischemic control or from the matched saline-treated group. These data suggest that significant accumulation of calcium in brain tissue is not an early event in ischemic-hyperglycemic brain damage, and thus does not provide support for a role of calcium in the production of this form of ischemic damage.

A comparison of the effects of fish oil and flaxseed oil on cardiac allograft chronic rejection in rats

2008 ◽  
Vol 294 (3) ◽  
pp. H1452-H1458 ◽  
Author(s):  
Rgia A. Othman ◽  
Miyoung Suh ◽  
Gabor Fischer ◽  
Nazila Azordegan ◽  
Natalie Riediger ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Fish Oil ◽  
Plasma Levels ◽  
Chronic Rejection ◽  
Graft Function ◽  
Hdl Cholesterol ◽  
Treated Group ◽  
Flaxseed Oil ◽  
Cardiac Allograft

Both fish and flaxseed oils are major sources of different n-3 fatty acids. Beneficial effects of fish oil on posttransplantation complications have been reported. The current study aimed to compare the effects of flaxseed and fish oils in a rat cardiac allograft model. Male Fischer and Lewis rats were used as donors and recipients, respectively, to generate a heterotopic cardiac allograft model. Animals were randomly assigned into three groups and fed a diet supplemented with 1) 5% (wt/wt) safflower oil (control, n = 7), 2) 5% (wt/wt) flaxseed oil ( n = 8), or 3) 2% (wt/wt) fish oil ( n = 7), and an intraperitoneal injection of cyclosporine A (CsA; 1.5 mg·kg−1·day−1) over 12 wk. Body weight, blood pressure, plasma levels of lipids, CsA, select cytokines, as well as graft function and chronic rejection features were assessed. Body weight and blood CsA levels were similar among the groups. Relative to controls, both treated groups had lower systolic and diastolic blood pressure and plasma levels of macrophage chemotactic protein-1. Treatment with fish oil significantly ( P < 0.05) lowered plasma levels of triglycerides, total cholesterol, and LDL-cholesterol. HDL-cholesterol concentrations were significantly higher ( P < 0.05) in the flaxseed oil-treated group compared with the other two groups. Both flaxseed oil and fish oil may provide similar biochemical, hemodynamic, and inflammatory benefits after heart transplantation; however, neither of the oils was able to statistically significantly impact chronic rejection or histological evidence of apparent cyclosporine-induced nephrotoxicity in this model.

Ligustrazine activate the PPAR-γ pathway and play a protective role in vascular calcification

Vascular ◽  
2021 ◽  
pp. 170853812110514
Author(s):  
Hui Li ◽  
Min Yang
Keyword(s):  
Vascular Calcification ◽  
Chondrogenic Differentiation ◽  
Calcium Content ◽  
Protective Role ◽  
Peroxisome Proliferation ◽  
Rt Pcr ◽  
Alizarin Red ◽  
Ppar Γ ◽  
Related Proteins

Objective The purpose of this study was to explore the role of ligustrazine in vascular calcification. Methods After β-GP stimulation, vascular smooth muscle cells (VSMCs) were detected by Alizarin Red Staing staining. Calcium content and alkaline phosphatase (ALP) activity were detected by intracellular calcium assay kit and ALP assay kit, respectively. The expression of peroxisome proliferation-activated receptor (PPAR-γ) pathway–related proteins was detected by Western blot. PPAR-γ, MSX2, osteopontin (OPN), sclerostin, and BGP were detected by RT-PCR. Results β-GP induced the decreased activity and expression of PPAR-γ and ALP in VSMCs, while ligustrazine activated the expression of PPAR-γ. Through activation of PPAR-γ, ligustrazine decreased β-GP–induced VSMC calcification, decreased the expression of markers of osteogenesis and chondrogenic differentiation, and increased the expression of VSMC markers. Conclusion Ligustrazine activates the PPAR-γ pathway and plays a protective role in vascular calcification.

scholarly journals Phosphate Homeostasis, Inflammation and the Regulation of FGF-23

2018 ◽  
Vol 43 (6) ◽  
pp. 1742-1748 ◽  
Author(s):  
Florian Lang ◽  
Christina Leibrock ◽  
Aleksandra A. Pandyra ◽  
Christos Stournaras ◽  
Carsten A. Wagner ◽  
...  
Keyword(s):  
Phosphate Homeostasis ◽  
Fgf 23

scholarly journals Effects of proportional high-protein/low-carbohydrate formulated diet consumption in diabetic rats: Beneficial impact on glycemic and weight control

2020 ◽  
Vol 20 (07) ◽  
pp. 16984-16996
Author(s):  
MMC Anyakudo ◽  
◽  
DO Adeniji ◽  
Keyword(s):  
Body Weight ◽  
Wistar Rats ◽  
Treated Group ◽  
Morphological Features ◽  
High Protein ◽  
Control Group ◽  
Formulated Diet ◽  
Low Carbohydrate ◽  
Male Wistar Rats ◽  
And Control

The metabolic response to nutrient ingestion and the rate of digestion and absorption of nutrient molecules in bowel physiology plays an important role in the metabolic control of some human chronic non-infectious diseases. This experimentally-controlled designed nutritional study which lasted eight weeks aimed to determine the effects of proportional high-protein/low-carbohydrate (HP/LC) formulated diet on glycemic tolerance, glycemic control, body weight, organ weight and organ morphometry in healthy and diabetic adult male Wistar rats. Twenty-four male Wistar rats purchased from a disease-free stock were randomly categorized into four groups (n = 6, each) after two weeks acclimatization period in raised stainless steel cages with 6 mm2mesh floor and replaceable numbered blotters papers placed under each cage in a well-ventilated animal house. Animal groups include: Healthy control group (HC), Healthy treated group (HT), Diabetic control group (DC) and Diabetic treated group (DT. The animals were fed according to the experimental design with water ad libitumfor eight weeks. Diabetes was inducted with freshly prepared alloxan monohydrate solution (150 mg/kg bw, intraperitoneally). Body weights and fasting blood sugar concentrations were measured twice weekly, while oral glucose tolerance test was conducted on the last day of the eighth-week study and subsequently followed by organs extraction after anesthesia for weight and gross assessment. Proportional high-protein/low-carbohydrate formulated diet caused significant reduction in mean body weight of treated diabetic (DT: 22.6%; P= .001) and healthy (HT: 5.8%; P= .007) rats while the control animals on control diet recorded significant (P< .05) increase in body weight gain (DC: 12.4%; HC: 11.2%). Glycemic tolerance and control improved significantly in diabetic treated rats over that of the healthy treated rats. Gross morphometry of the extracted organs (kidneys, liver, heart, lungs, spleen and testes) revealed sustained normal morphological features without any visible lesion. In conclusion, consumption of proportional high-protein/low-carbohydrate formulated diet enhanced body weight reduction and sustained normal organ morphological features with good glycemic tolerance and control in experimental rats, suggesting its dietary potentiality, safety and suitability to ameliorate obesity-related diabetes.

scholarly journals Triptolide Attenuates Vascular Calcification by Upregulating Expression of miRNA-204

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu-qiang Pei ◽  
Yong-qiu Zheng ◽  
Yao-dong Ding ◽  
Qi-xiang Xu ◽  
Di Cao ◽  
...  
Keyword(s):  
Vascular Calcification ◽  
Molecular Mechanisms ◽  
Therapeutic Option ◽  
Calcium Content ◽  
Rat Aorta ◽  
Protective Role ◽  
Bone Morphogenetic Protein 2 ◽  
Dependent Manner ◽  
Protective Effects ◽  
Alp Activity

Background: Triptolide (TP), a naturally derived compound from Tripterygium wilfordii, has been proven effective in protecting against cardiovascular system, but the molecular mechanisms underlying its protective effects are poorly understood. In the current study, we sought to test the potential protective role of TP in the regulation of vascular calcification in a rat model and explore whether TP attenuates medial vascular calcification by upregulating miRNA-204.Methods: Vitamin D3 plus nicotine (VDN) was used to induce a vascular calcification (VC) model of rat aorta. Von Kossa and Hematoxylin-Eosin staining were applied to assess the degree of calcification of rat aortas. Calcium content and alkaline phosphatase activity were measured. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was applied to quantify miRNA-204 expression. The localization of runt-related transcription factor-2 (RUNX2) and bone morphogenetic protein-2 (BMP2) expressions were detected by immunohistochemistry and western blotting.Results: Administration of TP greatly reduced vascular calcification in a dose-dependent manner compared with VC controls. The increase in ALP activity and calcium content was ameliorated by TP. Moreover, protein expression levels of BMP2 and RUNX2 were significantly reduced in calcified aortas. MiRNA-204 expression was increased in the TP-treated groups compared with VC controls and the effects of TP were reversed by the intravenous injection of miRNA-204-interfering lentivirus. However, the miRNA-204-overexpressing lentivirus had no additional effects on ALP activity, calcium content, BMP2 and RUNX2 expressions compared with those from TP group.Conclusion: TP inhibited BMP2 and RUNX2 expression and attenuated vascular calcification via upregulating the level of miRNA-204. TP appears to be a potential new therapeutic option for treating vascular calcification.

scholarly journals Vascular calcification has a role in acute non-renal phosphate clearance

2020 ◽  
Author(s):  
Mandy E Turner ◽  
Austin P Lansing ◽  
Paul S Jeronimo ◽  
Lok Hang Lee ◽  
Bruno A Svajger ◽  
...  
Keyword(s):  
Vascular Calcification ◽  
Phosphate Uptake ◽  
Mineral Metabolism ◽  
Extracellular Fluid ◽  
Systemic Response ◽  
Phosphate Homeostasis ◽  
Rat Models ◽  
Oral Consumption ◽  
Circulating Levels ◽  
Systemic Disposition

AbstractRationaleNon-renal extravasation of phosphate from the circulation and transient accumulation into tissues and extracellular fluid is a regulated process of acute phosphate homeostasis that is not well understood. Following oral consumption of phosphate, circulating levels normalize long before urinary excretion has been completed. This process is especially relevant in the setting of chronic kidney disease (CKD), where phosphate exposure is prolonged due to inefficient kidney excretion. Furthermore, CKD-associated dysregulation of mineral metabolism exacerbates pathological accumulation of phosphate causing vascular calcification (VC).ObjectiveDetermine whether the systemic response to acute phosphate challenges is altered by the development and progression of VC.Methods/ResultsAcute circulating and tissue deposition of an acute phosphate challenge was assessed in two rat models of VC using radio-labelled phosphate tracer. In an adenine-induced model of CKD with VC, animals with VC had a blunted elevation of circulating 33PO4 following oral phosphate administration and the discordant deposition could be traced to the calcifying vasculature. In a non-CKD model of VC, VC was induced with 0.5ug/kg calcitriol and then withdrawn. The radio-labelled phosphate challenge was given to assess for vascular preference for phosphate uptake with and without the presence of an active calcification stimulus. The new transport to the calcifying vasculature correlates to the pre-existing burden of calcification, and can be substantially attenuated by removing the stimulus for calcification. The accrual is stimulated by a phosphate challenge, and not present in the same degree during passive disposition of circulating phosphate.ConclusionsOur data indicate that calcifying arteries alter the systemic disposition of a phosphate challenge and acutely deposit substantial phosphate. This study supports the importance of diet as it relates to acute fluctuations of circulating phosphate and the importance of bioavailability and meal-to-meal management in CKD patients as a mediator of cardiovascular risk.

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