The effect of calcitriol, paricalcitol, and a calcimimetic on extraosseous calcifications in uremic rats

Vitamin D derivatives and calcimimetics are used to treat secondary hyperparathyroidism in patients with chronic renal failure. We investigated the effect of calcitriol, paricalcitol, and the calcimimetic AMG 641 on soft-tissue calcification in uremic rats with secondary hyperparathyroidism. Control and uremic rats were treated with vehicle, calcitriol, paricalcitol, AMG 641, or a combination of AMG 641 plus calcitriol or paricalcitol. Parathyroid hormone levels were reduced by all treatments but were better controlled by the combination of paricalcitol and AMG 641. The calcimimetic alone did not induce extraosseous calcification but co-administration of AMG 641 reduced soft-tissue calcification and aortic mineralization in both calcitriol- and paricalcitol-treated rats. Survival was significantly reduced in rats treated with calcitriol and this mortality was attenuated by co-treatment with AMG 641. Our study shows that extraskeletal calcification was present in animals treated with calcitriol and paricalcitol but not with AMG 641. When used in combination with paricalcitol, AMG 641 provided excellent control of secondary hyperparathyroidism and prevented mortality associated with the use of vitamin D derivatives without causing tissue calcification

Energy-dense diets increase FGF23, lead to phosphorus retention and promote vascular calcifications in rats

Rats with normal renal function (Experiment 1, n = 12) and uninephrectomized (1/2Nx) rats (Experiment 2, n = 12) were fed diets with normal P (NP) and either normal (NF) or high fat (HF). Rats with intact renal function (Experiment 3, n = 12) were also fed NF or HF diets with high P (HP). Additionally, uremic (5/6Nx) rats (n = 16) were fed HP diets with NF or HF. Feeding the HF diets resulted in significant elevation of plasma FGF23 vs rats fed NF diets: Experiment 1, 593 ± 126 vs 157 ± 28 pg/ ml (p < 0.01); Experiment 2, 538 ± 105 vs 250 ± 18 pg/ml (p < 0.05); Experiment 3, 971 ± 118 vs 534 ± 40 pg/ml (p < 0.01). Rats fed HF diets showed P retention and decreased renal klotho (ratio klotho/actin) vs rats fed NF diets: Experiment 1, 0.75 ± 0.06 vs 0.97 ± 0.02 (p < 0.01); Experiment 2, 0.69 ± 0.07 vs 1.12 ± 0.08 (p < 0.01); Experiment 3, 0.57 ± 0.19 vs 1.16 ± 0.15 (p < 0.05). Uremic rats fed HF diet showed more severe vascular calcification (VC) than rats fed NF diet (aortic Ca = 6.3 ± 1.4 vs 1.4 ± 0.1 mg/g tissue, p < 0.001). In conclusion, energy-rich diets increased plasma levels of FGF23, a known risk factor of cardiovascular morbidity and mortality. Even though FGF23 has major phosphaturic actions, feeding HF diets resulted in P retention, likely secondary to decreased renal klotho, and aggravated uremic V

In vascular smooth muscle cells paricalcitol prevents phosphate-induced Wnt/β-catenin activation

The present study investigates the differential effect of two vitamin D receptor agonists, calcitriol and paricalcitol, on human aortic smooth muscle cells calcification in vitro. Human vascular smooth muscle cells were incubated in a high phosphate (HP) medium alone or supplemented with either calcitriol 10−8M (HP + CTR) or paricalcitol 3·10−8 M (HP + PC). HP medium induced calcification, which was associated with the upregulation of mRNA expression of osteogenic factors such as bone morphogenetic protein 2 (BMP2), Runx2/Cbfa1, Msx2, and osteocalcin. In these cells, activation of Wnt/β-catenin signaling was evidenced by the translocation of β-catenin into the nucleus and the increase in the expression of direct target genes as cyclin D1, axin 2, and VCAN/versican. Addition of calcitriol to HP medium (HP + CTR) further increased calcification and also enhanced the expression of osteogenic factors together with a significant elevation of nuclear β-catenin levels and the expression of cyclin D1, axin 2, and VCAN. By contrast, the addition of paricalcitol (HP + PC) not only reduced calcification but also downregulated the expression of BMP2 and other osteoblastic phenotype markers as well as the levels of nuclear β-catenin and the expression of its target genes. The role of Wnt/β-catenin on phosphate- and calcitriol-induced calcification was further demonstrated by the inhibition of calcification after addition of Dickkopf-related protein 1 (DKK-1), a specific natural antagonist of the Wnt/β-catenin signaling pathway. In conclusion, the differential effect of calcitriol and paricalcitol on vascular calcification appears to be mediated by a distinct regulation of the BMP and Wnt/β-catenin signaling pathways

Magnesium Inhibits Wnt/β-Catenin Activity and Reverses the Osteogenic Transformation of Vascular Smooth Muscle Cells

Magnesium reduces vascular smooth muscle cell (VSMC) calcification in vitro but the mechanism has not been revealed so far. This work used only slightly increased magnesium levels and aimed at determining: a) whether inhibition of magnesium transport into the cell influences VSMC calcification, b) whether Wnt/β-catenin signaling, a key mediator of osteogenic differentiation, is modified by magnesium and c) whether magnesium can influence already established vascular calcification. Human VSMC incubated with high phosphate (3.3 mM) and moderately elevated magnesium (1.4 mM) significantly reduced VSMC calcification and expression of the osteogenic transcription factors Cbfa-1 and osterix, and up-regulated expression of the natural calcification inhibitors matrix Gla protein (MGP) and osteoprotegerin (OPG). The protective effects of magnesium on calcification and expression of osteogenic markers were no longer observed in VSMC cultured with an inhibitor of cellular magnesium transport (2-aminoethoxy-diphenylborate [2-APB]). High phosphate induced activation of Wnt/β-catenin pathway as demonstrated by the translocation of β-catenin into the nucleus, increased expression of the frizzled-3 gene, and downregulation of Dkk-1 gene, a specific antagonist of the Wnt/β-catenin signaling pathway. The addition of magnesium however inhibited phosphate-induced activation of Wnt/β-catenin signaling pathway. Furthermore, TRPM7 silencing using siRNA resulted in activation of Wnt/β-catenin signaling pathway. Additional experiments were performed to test the ability of magnesium to halt the progression of already established VSMC calcification in vitro. The delayed addition of magnesium decreased calcium content, down-regulated Cbfa-1 and osterix and up-regulated MGP and OPG, when compared with a control group. This effect was not observed when 2-APB was added. In conclusion, magnesium transport through the cell membrane is important to inhibit VSMC calcification in vitro. Inhibition of Wnt/β-catenin by magnesium is one potential intracellular mechanism by which this anti-calcifying effect is achieved

Incidencia y pronóstico del ictus minor y ataque isquémico transitorio de alto riesgo en Nordictus: estudio IMMINENT

[Abstract] Background. Our primary aim was to investigate the incidence of non-cardioembolic minor acute ischemic stroke (AIS) and high-risk transient ischemic attack (TIA) and to identify predictors of stroke recurrence/death and severe bleeding. We also evaluated the rates of TIA, major vascular events, therapeutic management and predictors of poor functional outcome at 3 months in these patients. Methods. We retrospectively reviewed data from all stroke patients evaluated at the emergency department of 19 hospitals belonging to the NORDICTUS stroke network between July and December 2019. Consecutive patients with non-cardioembolic minor AIS (NIHSS ≤5) and high-risk TIA (ABCD2 ≥6 or ipsilateral stenosis ≥50%) were included. We recorded clinical, neuroimaging and therapeutic variables. Follow-up was performed at 30 and 90 days. Functional prognosis was assessed with the modified Rankin scale score (mRS). Results. Of 8275 patients, 1679 (20%) fulfilled IMMINENT criteria (1524 AIS/155 TIA), resulting in a global incidence of 48/100,000 inhabitants per-year. Recurrent stroke/death occurred in 73 (4.3%) patients. Extracranial ipsilateral stenosis (>50%): HR 1.999 (95% CI: 1.115–3.585, p = 0.020) and lack of hyperacute cerebral arterial assessment: HR 1.631 (95% CI: 1.009–2.636, p = 0.046) were associated with recurrent stroke/death at 90 days. Intracranial stenosis was associated with poor prognosis (p = 0.044). Reperfusion therapy was given to 147 (9%) and urgent double antiplatelet therapy (DAPT) to 320 (21%) patients. Conclusion. Twenty percent of our stroke patients presented as non-cardioembolic high-risk TIA or minor AIS. Extracranial ipsilateral stenosis and lack of hyperacute cerebral arterial assessment were predictors of stroke recurrence/death; intracranial stenosis was associated with poor outcome. Despite current recommendations there was a low penetrance of DAPT.[Resumen] Introducción. Nuestro objetivo principal fue investigar la incidencia de ictus minor no cardioembólico y ataque isquémico transitorio (AIT) de alto riesgo, además de identificar predictores de recurrencia de ictus/muerte y sangrado grave. Evaluamos los porcentajes de AIT, eventos vasculares mayores, manejo terapéutico y predictores de mal pronóstico funcional. Métodos. Estudio retrospectivo de todos los pacientes con ictus evaluados en urgencias de 19 hospitales de la RED NORDICTUS entre julio-diciembre de 2019. Se incluyeron pacientes consecutivos con ictus minor no cardioembólico (National Institute of Health Stroke Scale [NIHSS] ≤ 5) y AIT de alto riesgo (ABCD2 ≥ 6 o estenosis ipsilateral ≥ 50%). Registramos variables clínicas, de neuroimagen y terapéuticas. Se realizó seguimiento a los 30 y 90 días. El pronóstico funcional se determinó mediante la escala de Rankin modificada (mRS). Resultados. De 8.275 pacientes, 1.679 (20%) cumplieron criterios del estudio IMMINENT (1.524 ictus/155 AIT), la incidencia global fue 48/100.000 h habitantes-año. Hubo recurrencias de ictus/muerte en 73 (4,3%) pacientes. La estenosis extracraneal ipsilateral (>50%): HR 1.999 (IC 95%: 1.115-3.585); p = 0,020 y la ausencia de estudio cerebrovascular hiperagudo: HR 1.631 (IC 95%: 1.009-2.636); p = 0.046, fueron predictores de ictus/muerte a 90 días. La estenosis intracraneal se asoció a mal pronóstico (p = 0,044). Se administró terapia de reperfusión a 147 (9%) y doble antiagregación a 320 (21%) pacientes. Conclusión. Un 20% de los pacientes se presentó como ictus minor o AIT de alto riesgo. La estenosis extracraneal ipsilateral y la ausencia de estudio neurovascular hiperagudo fueron predictores de ictus/muerte; la estenosis intracraneal se asoció con mal pronóstico. A pesar de las recomendaciones actuales hay baja penetrancia de doble antiagregación.This study was sponsored by AstraZeneca, funder had no involvement in the analysis or interpretation of the data, or the writing of the manuscript. MER-A was funded by the Instituto de Salud Carlos III (ISCIII) JR19/00020, co-funded by ERDF/ESF, “A way to make Europe”/“Investing in your future”). Investigators of this study belong to the RETICS-RICORS ICTUS financed by ISCIII (RD21/0006/0005-RD21/0006/0016-RD21/0006/0017-RD21/0006/0020-RD21/0006/0022).Instituto de Salud Carlos III; JR19/0002

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries