2-oxothiazolidine-4-carboxylic acid inhibits vascular calcification via induction of glutathione synthesis

© 2020 The Author(s). This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Arterial medial calcification (AMC), the deposition of hydroxyapatite in the medial layer of the arteries, is a known risk factor for cardiovascular events. Oxidative stress is a known inducer of AMC and endogenous antioxidants, such as glutathione (GSH), may prevent calcification. GSH synthesis, however, can be limited by cysteine levels. Therefore, we assessed the effects of the cysteine prodrug 2‐oxothiazolidine‐4‐carboxylic acid (OTC), on vascular smooth muscle cell (VSMC) calcification to ascertain its therapeutic potential. Human aortic VSMCs were cultured in basal or mineralising medium (1 mM calcium chloride/sodium phosphate) and treated with OTC (1–5 mM) for 7 days. Cell‐based assays and western blot analysis were performed to assess cell differentiation and function. OTC inhibited calcification ≤90%, which was associated with increased ectonucleotide pyrophosphatase/phosphodiesterase activity, and reduced apoptosis. In calcifying cells, OTC downregulated protein expression of osteoblast markers (Runt‐related transcription factor 2 and osteopontin), while maintaining expression of VSMC markers (smooth muscle protein 22α and α‐smooth muscle actin). GSH levels were significantly reduced by 90% in VSMCs cultured in calcifying conditions, which was associated with declines in expression of gamma‐glutamylcysteine synthetase and GSH synthetase. Treatment of calcifying cells with OTC blocked the reduction in expression of both enzymes and prevented the decline in GSH. This study shows OTC to be a potent and effective inhibitor of in vitro VSMC calcification. It appears to maintain GSH synthesis which may, in turn, prevent apoptosis and VSMCs gaining osteoblast‐like characteristics. These findings may be of clinical relevance and raise the possibility that treatment with OTC could benefit patients susceptible to AMC.Peer reviewe

Semicarbazide-Sensitive Amine Oxidase (SSAO) and Lysyl Oxidase (LOX) Association in Rat Aortic Vascular Smooth Muscle Cells

open access articleVascular smooth muscle cells (VSMCs) are the main stromal cells in the medial layer of the vascular wall. These cells produce the extracellular matrix (ECM) and are involved in many pathological changes in the vascular wall. Semicarbazide-sensitive amine oxidase (SSAO) and lysyl oxidase (LOX) are vascular enzymes associated with the development of atherosclerosis. In the vascular smooth muscle cells, increased SSAO activity elevates reactive oxygen species (ROS) and induces VSMCs death; increased LOX induces chemotaxis through hydrogen peroxide dependent mechanisms; and decreased LOX contributes to endothelial dysfunction. This study investigates the relationship between SSAO and LOX in VSMCs by studying their activity, protein, and mRNA levels during VSMCs passaging and after silencing the LOX gene, while using their respective substrates and inhibitors. At the basal level, LOX activity decreased with passage and its protein expression was maintained between passages. βAPN abolished LOX activity (** p < 0.01 for 8 vs. 3 and * p < 0.05 for 5 vs. 8) and had no effect on LOX protein and mRNA levels. MDL72527 reduced LOX activity at passage 3 and 5 (## p < 0.01) and had no effect on LOX protein, and mRNA expression. At the basal level, SSAO activity also decreased with passage, and its protein expression was maintained between passages. MDL72527 abolished SSAO activity (**** p < 0.0001 for 8 vs. 3 and * p < 0.05 for 5 vs. 8), VAP-1 expression at passage 5 (** p < 0.01) and 8 (**** p < 0.0001), and Aoc3 mRNA levels at passage 8 (* p < 0.05). βAPN inhibited SSAO activity (**** p < 0.0001 for 5 vs. 3 and 8 vs. 3 and * p < 0.05 for 5 vs. 8), VAP-1 expression at passage 3 (* p < 0.05), and Aoc3 mRNA levels at passage 3 (* p < 0.05). Knockdown of the LOX gene (**** p < 0.0001 for Si6 vs. Sictrl and *** p < 0.001 for Si8 vs. Sictrl) and LOX protein (** p < 0.01 for Si6 and Si8 vs. Sictrl) in VSMCs at passage 3 resulted in a reduction in Aoc3 mRNA (#### p < 0.0001 for Si6 vs. Sictrl and ### p < 0.001 for Si8 vs. Sictrl) and VAP-1 protein (# p < 0.05 for Si8 vs. Sictrl). These novel findings demonstrate a passage dependent decrease in LOX activity and increase in SSAO activity in rat aortic VSMCs and show an association between both enzymes in early passage rat aortic VSMCs, where LOX was identified as a regulator of SSAO activity, protein, and mRNA expression

Uremic serum-induced calcification of human aortic smooth muscle cells is a regulated process involving Klotho and RUNX2

© 2019 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY).Vascular calcification (VC) is common in subjects with chronic kidney disease (CKD) and is associated with increased cardiovascular risk. It is an active process involving transdifferentiation of arterial smooth muscle cells (SMCs) into osteogenic phenotype. We investigated the ability of serum from CKD subjects to induce calcification in human SMCs in vitro (calcific potential of sera: CP), and associated changes in expression of Runt-related transcription factor 2 (RUNX2), SM22a, and Klotho. Sera from subjects with CKD (18 stage 3, 17 stage 4/5, and 29 stage 5D) and 20 controls were added to human cultured SMCs and CP quantified. The CP of CKD sera was greater (P>0.01) than that of controls, though not influenced by CKD stage. Modification of diet in renal disease estimated glomerular filtration rate (MDRD-4 eGFR) (P>0.001), serum phosphate (P=0.042), receptor activator of nuclear factor ?appa-B ligand (RANKL) (P=0.001), parathyroid hormone (PTH) (P=0.014), and high-density lipoprotein (HDL)/cholesterol ratio (P=0.026) were independent predictors of CP accounting for 45% of variation. Adding calcification buffer (CB: calcium chloride [7 mM] and β-glycerophosphate [7 mM]) increased the CP of control sera to approximate that of CKD sera. CP of CKD sera was unchanged. CKD sera increased RUNX2 expression (P>0.01) in human SMCs and decreased SM22a expression (P>0.05). Co-incubating control but not CKD serum with CB further increased RUNX2 expression (P>0.01). Both SM22a and Klotho expression decreased significantly (P>0.01) in the presence of CKD serum, and were virtually abolished with stage 5D sera. These findings support active regulation by CKD serum of in vitro VC by induction of RUNX2 and suppression of SM22a and Klotho.Peer reviewe

Serum cytokine levels as markers of paralytic ileus following robotic radical prostatectomy at different pneumoperitoneum pressures.

open access articleBackground: To evaluate intraoperative and postoperative cytokines in patients who underwent robotic prostatectomy (RP) at a pressure of 12 or 15mmHg, and the risk of postoperative ileus. Materials and methods: We presented the first series evaluating intraoperative and postoperative cytokines in patients undergoing RP at a pressure of 12 or 15mmHg by a single surgeon. Changes in cytokine concentrations were shown to correlate with surgical outcomes and pathological states. The study investigated the changes in cytokine concentrations (interferon-g, tumor necrosis factor-a, interleukin-1b [IL-1b], IL-2, IL-4, IL-6, IL-12, and IL-17) at different pneumoperitoneum pressures and their potential role in the development of postoperative ileus. Results: The data on 10 consecutive patients confirmed that a lower pneumoperitoneum pressure was associated with lower cytokine levels and a lower risk of ileus. There were increased levels of postoperative interferon-g, tumor necrosis factor-a, IL-12p70, IL-1b, IL-2, IL-4, and IL-17a at 15mmHg when compared to 12mmHg. Conclusions: The data indicated that lower pressure RP reduced intra-/postoperative cytokine levels confirming our hypothesis. Larger patient numbers are required to further validate this but the implications of this data will benefit not only urological patients but also other speciality patients undergoing minimally invasive surgery

Encapsulation of lactobacillus casei into calcium pectinate-chitosan beads for enteric delivery

Gel beads were prepared by extrusion of various types of pectin into 0.15 M calcium chloride. Size, morphology, and textural properties of 3 types of beads were evaluated and it was established that the use of 3 w/v % amidated pectin provides the optimal characteristics suitable for encapsulation of live bacteria. Lactobacillus casei NCIMB 30185 (PXN37) was encapsulated into calcium pectinate gel through the extrusion of a live bacteria dispersion in 3 w/v % pectin into a solution of calcium chloride. The capsules were then additionally coated with chitosan. The viability of bacteria within these capsules was studied under model gastrointestinal conditions in vitro (simulated gastric and intestinal juices). It was established that pectin-chitosan capsules can provide protection to L. casei from the gastric acid and result in high levels of viable bacteria released in the intestine

Diabetes confers in vitro calcific potential on serum which associates with in-vivo vascular calcification

This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution Licence 4.0 (CC-BY).Although vascular calcification (VC) is prevalent in Type 2 diabetes mellitus (T2DM), underlying mechanisms remain unclear. Neither is it known whether T2DM confers calcific potential (CP) on serum, enabling it to induce VC outside the disease milieu. We, therefore, investigated the CP of serum from controls and subjects with T2DM with and without in vivo VC. Samples from 20 healthy controls and 44 age- and sex-matched patients with T2DM with modification of diet in renal disease estimated glomerular filtration rate (MDRD-4 eGFR) > 60 ml·min-1 were analysed for CP using rat aortic smooth muscle cells in vitro. CT scans of femoral arteries identified individuals with in vivo calcification. Serum from subjects with T2DM revealed significantly greater CP than controls. This was further enhanced in the presence of in vivo VC. Addition of β-glycerophosphate (β-GP) plus CaCl2 increased the CP of T2DM serum but not of controls. Along with age, CP was an independent predictor of the presence of VC. In receiver operator curve (ROC) analysis, CP was a significant predictor of femoral arterial VC (C-statistic 0.70: P=0.009). The distribution of CP was bimodal around a cutoff of 100 nmoles of Ca2+ protein mg-1, with a higher proportion of Type 2 diabetes subjects with in vivo calcification (T2DM+) sera above the cutoff value. This group also showed elevated levels of osteoprotegerin (OPG) and matrix Gla protein (MGP). Diabetes confers CP on the serum which is enhanced by the presence of in vivo VC. The CP acquired may be dependent on levels of OPG and MGP. These findings may be clinically relevant for early identification of individuals at risk of VC and for informing therapeutic strategies.Peer reviewe

Post-transcriptional divergence in the regulation of CAT-2A, CAT-2B and iNOS expression by dexamethasone in vascular smooth muscle cells

Upregulation of l-arginine transport by pro-inflammatory mediators is a widely reported phenomenon which accompanies the expression of the inducible nitric oxide synthase (iNOS) enzyme in various cells. Both processes require de novo protein synthesis which may be regulated differentially through diverging signalling pathways. This is particularly defined by observations that the glucocorticoid dexamethasone, acting potentially through NF-κB, selectively blocks the expression of iNOS whilst having little or no effect on transport; suggesting that this ubiquitous transcription factor may not be required for induced transporter activity. This notion is however controversial as is the suggestion that dexamethasone may regulate iNOS expression exclusively through NF-κB. Thus, to further understand the mechanisms that control these processes, we have examined the level at which dexamethasone acts, investigating whether this involves NF-κB and whether the latter selectively regulates iNOS induction. Our current data directly demonstrate that induced l-arginine transport is critically dependent on the activation of NF-κB, and further confirmed its role in the induction of iNOS in rat aortic smooth muscle cells. More importantly, dexamethasone enhanced both iNOS and CAT gene expression but repressed iNOS protein with no noticeable effects on transporter function or indeed NF-κB activation. These novel and unexpected findings reflect the complex nature of the regulation of iNOS by glucocorticoids and prove, contrary to previous assumptions, that dexamethasone can regulate CAT gene expression despite failing to alter transporter function. Moreover, the effects of dexamethasone occur through a non-NF-κB-mediated action even though NF-κB is required for both processes.Peer reviewe

Uraemic serum induced calcification of human aortic smooth muscle cells is a regulated process involving Klotho and RUNX2

© 2019 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY).Vascular calcification (VC) is common in subjects with chronic kidney disease (CKD) and is associated with increased cardiovascular risk. It is an active process involving trans-differentiation of arterial smooth muscle cells (SMCs) into osteogenic phenotype. We investigated the ability of serum from CKD subjects to induce calcification in human SMCs in vitro (calcific potential of sera: CP), and associated changes in expression of RUNX2, SM22a and Klotho. Sera from subjects with CKD (18 stage 3, 17 stage 4/5, and 29 stage 5D) and 20 controls were added to human cultured SMCs and CP quantified. The CP of CKD sera was greater (p<0.01) than that of controls, though not influenced by CKD stage. MDRD-4 eGFR (p<0.001), serum phosphate (p= 0.042), RANKL (p= 0.001), PTH (p= 0.014) and HDL/Cholesterol ratio (p= 0.026) were independent predictors of CP accounting for 45% of variation. Adding calcification buffer (CB: calcium chloride [7mM] and β glycerophosphate [7mM]) increased the CP of control sera to approximate that of CKD sera. CP of CKD sera was unchanged. CKD sera increased RUNX2 expression (p<0.01) in human SMCs and decreased SM22a expression (p<0.05). Co-incubating control but not CKD serum with CB further increased RUNX2 expression (p<0.01). Both SM22a and Klotho expression decreased significantly (p<0.01) in the presence of CKD serum, and were virtually abolished with Stage 5D sera. These findings support active regulation by CKD serum of in vitro VC by induction of RUNX2 and suppression of SM22a and Klotho.Peer reviewe

The Impact of Semicarbazide Sensitive Amine Oxidase Activity on Rat Aortic Vascular Smooth Muscle Cells.

open access articleSemicarbazide-sensitive amine oxidase (SSAO) is both a soluble- and membrane-bound transmembrane protein expressed in the vascular endothelial and in smooth muscle cells. In vascular endothelial cells, SSAO contributes to the development of atherosclerosis by mediating a leukocyte adhesion cascade; however, its contributory role in the development of atherosclerosis in VSMCs has not yet been fully explored. This study investigates SSAO enzymatic activity in VSMCs using methylamine and aminoacetone as model substrates. The study also addresses the mechanism by which SSAO catalytic activity causes vascular damage, and further evaluates the contribution of SSAO in oxidative stress formation in the vascular wall. SSAO demonstrated higher affinity for aminoacetone when compared to methylamine (Km = 12.08 µM vs. 65.35 µM). Aminoacetone- and methylamine-induced VSMCs death at concentrations of 50 & 1000 µM, and their cytotoxic effect, was reversed with 100 µM of the irreversible SSAO inhibitor MDL72527, which completely abolished cell death. Cytotoxic effects were also observed after 24 h of exposure to formaldehyde, methylglyoxal and H2O2. Enhanced cytotoxicity was detected after the simultaneous addition of formaldehyde and H2O2, as well as methylglyoxal and H2O2. The highest ROS production was observed in aminoacetone- and benzylamine-treated cells. MDL72527 abolished ROS in benzylamine-, methylamine- and aminoacetone-treated cells (**** p < 0.0001), while βAPN demonstrated inhibitory potential only in benzylamine-treated cells (* p < 0.05). Treatment with benzylamine, methylamine and aminoacetone reduced the total GSH levels (**** p < 0.0001); the addition of MDL72527 and βAPN failed to reverse this effect. Overall, a cytotoxic consequence of SSAO catalytic activity was observed in cultured VSMCs where SSAO was identified as a key mediator in ROS formation. These findings could potentially associate SSAO activity with the early developing stages of atherosclerosis through oxidative stress formation and vascular damage

ACCEPTED MANUSCRIPT Diabetes confers in vitro calcific potential on serum which associates with in- vivo vascular calcification Clinical Science Running title: In vitro Calcific Potential of Type 2 Diabetes Serum ACR = Albumin Creatinine Ratio BCA = Bicin

Although vascular calcification (VC) is prevalent in typeʹ diabetes (T2DM), underlying mechanisms remain unclear. Neither is it known whether T2DM confers calcific potential (CP) to serum, enabling it to induce VC outside the disease milieu. We therefore investigated the CP of serum from controls and subjects with T2DM with and without in vivo VC. Samples from 20 healthy controls and 45 age-and sexmatched patients with T2DM with MDRD-eGFR&gt;60mL min-1 were analysed for CP using rat aortic smooth muscle cells in vitro. CT scans of femoral arteries identified individuals with in vivo calcification. Serum from subjects with T2DM revealed significantly greater CP than controls. This was further enhanced in the presence of in vivo VC. Addition ofȾ-glycerophosphate plus CaCl2 increased the CP of T2DM serum but not of controls. Along with age, CP was an independent predictor of the presence of VC. In ROC analysis, CP was ƒ significant predictor of femoral arterial VC (C-statistic 0.70: p= 0.009). The distribution of CP was bimodal around ƒ cutoff of 100 nmoles of Ca2+ protein mg-1, with ƒ higher proportion of T2DM+ sera above the cutoff value. This group also showed elevated levels of osteoprotegerin (OPG) and matrix gla protein (MGP). Diabetes confers CP to the serum which is enhanced by the presence of in vivo VC. The CP acquired may be dependent on levels of OPG and MGP. These findings may be clinically relevant for early identification of individuals at risk of VC and for informing therapeutic strategies. Diabetes confers in vitro calcific potential on serum which associates with in-vivo Abstract Although vascular calcification (VC) is prevalent in type 2 diabetes (T2DM), underlying mechanisms remain unclear. Neither is it known whether T2DM confers calcific potential (CP) to serum, enabling it to induce VC outside the disease milieu. We therefore investigated the CP of serum from controls and subjects with T2DM with and without in vivo VC. Samples from 20 healthy controls and 45 age-and sex-matched patients with T2DM with MDRD-eGFR&gt;60mL min -1 were analysed for CP using rat aortic smooth muscle cells in vitro. CT scans of femoral arteries identified individuals with in vivo calcification. Serum from subjects with T2DM revealed significantly greater CP than controls. This was further enhanced in the presence of in vivo VC. Addition of ȕ-glycerophosphate plus CaCl2 increased the CP of T2DM serum but not of controls. Along with age, CP was an independent predictor of the presence of VC. In ROC analysis, CP was a significant predictor of femoral arterial VC (C-statistic 0.70: p= 0.009). The distribution of CP was bimodal around a cutoff of 100 nmoles of Ca 2+ protein mg , with a higher proportion of T2DM+ sera above the cutoff value. This group also showed elevated levels of osteoprotegerin (OPG) and matrix gla protein (MGP). Diabetes confers CP to the serum which is enhanced by the presence of in vivo VC. The CP acquired may be dependent on levels of OPG and MGP. These findings may be clinically relevant for early identification of individuals at risk of VC and for informing therapeutic strategies