The protective effect of 1400W against ischaemia and reperfusion injury is countered by transient medullary kidney endothelial dysregulation.

Renal ischaemia and reperfusion (I/R) is caused by a sudden temporary impairment of the blood flow. I/R is a prevalent cause of acute kidney injury. As nitric oxide generated by inducible nitric oxide synthase (iNOS) has detrimental effects during I/R, the pharmacological blockade of iNOS has been proposed as a potential strategy to prevent I/R injury. The aim of this study was to improve the understanding of 1400W (an iNOS inhibitor) on renal I/R as a pharmacological strategy against kidney disease. BALB/c mice received 30 min of bilateral ischaemia, followed by 48 h or 28 days of reperfusion. Vehicle or 1400W (10 mg/kg) was administered 30 min before inducing ischaemia. We found that after 48 h of reperfusion 1400W decreased the serum creatinine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin and proliferating cell nuclear antigen 3 in the I/R animals. Unexpectedly, we observed mRNA upregulation of genes involved in kidney injury, cell-cycle arrest, inflammation, mesenchymal transition and endothelial activation in the renal medulla of sham animals treated with 1400W. We also explored if 1400W promoted chronic kidney dysfunction 28 days after I/R and did not find significant alterations in renal function, fibrosis, blood pressure or mortality. The results provide evidence that 1400W may have adverse effects in the renal medulla. Importantly, our data point to 1400W-induced endothelial dysfunction, establishing therapeutic limitations for its use. KEY POINTS: Acute kidney injury is a global health problem associated with high morbidity and mortality. The pharmacological blockade of inducible nitric oxide synthase (iNOS) has been proposed as a potential strategy to prevent AKI induced by ischaemia and reperfusion (I/R). Our main finding is that 1400W, a selective and irreversible iNOS inhibitor with low toxicity that is proposed as a therapeutic strategy to prevent kidney I/R injury, produces aberrant gene expression in the medulla associated to tissue injury, cell cycle arrest, inflammation, mesenchymal transition and endothelial activation. The negative effect of 1400W observed in the renal medulla at 48 h from drug administration, is transient as it did not translate into a chronic kidney disease condition.

Low-Chloride Diet Prevents the Development of Arterial Hypertension and Protects Kidney Function in Angiotensin II-Infused Mice.

INTRODUCTION: A comprehensive pathophysiological mechanism to explain the relationship between high-salt intake and hypertension remains undefined. Evidence suggests that chloride, as the accompanying anion of sodium in dietary salt, is necessary to develop hypertension. We evaluated whether reducing dietary Cl- while keeping a standard Na+ intake modified blood pressure, cardiac hypertrophy, renal function, and vascular contractility after angiotensin II (AngII) infusion. METHODS: C56BL/6J mice fed with standard Cl- diet or a low-Cl- diet (equimolar substitution of Cl- by a mixture of Na+ salts, both diets with standard Na+ content) received AngII (infusion of 1.5 mg/kg/day) or vehicle for 14 days. We measured systolic blood pressure (SBP), glomerular filtration rate (GFR), natriuretic response to acute saline load, and contractility of aortic rings from mice infused with vehicle and AngII, in standard and low-Cl- diet. RESULTS: The mice fed the standard diet presented increased SBP and cardiac hypertrophy after AngII infusion. In contrast, low-Cl- diet prevented the increase of SBP and cardiac hypertrophy. AngII-infused mice fed a standard diet presented hampered natriuretic response to saline load, meanwhile the low-Cl- diet preserved natriuretic response in AngII-infused mice, without change in GFR. Aortic rings from mice fed with standard diet or low-Cl- diet and infused with AngII presented a similar contractile response. CONCLUSION: We conclude that the reduction in dietary Cl- as the accompanying anion of sodium in salt is protective from AngII pro-hypertensive actions due to a beneficial effect on kidney function and preserved natriuresis.

[Efficacy of a standardized and simplified strategy for the treatment of high blood pressure in Chile: the HEARTS Initiative in the AmericasEficácia de uma estratégia padronizada e simplificada para o tratamento da hipertensão arterial no Chile: a iniciativa HEARTS nas Américas]. / Eficacia de una estrategia estandarizada y simplificada para tratamiento de la hipertensión arterial en Chile: la Iniciativa HEARTS en las Américas.

Objective: To evaluate the effectiveness of a standardized and simplified protocol based on the technical pillars of the HEARTS Initiative for the control of hypertensive patients in the Cardiovascular Health Program at the first level of care in Chile. Methods: Longitudinal observational study (historical cohort) in two family health centers at the first level of care in Santiago. The control of blood pressure in hypertensive adults using a standardized and simplified protocol was compared to the usual protocol based on national guidelines. Innovations in the standardized protocol included changes in how the health team is coordinated, initiation of pharmacological treatment immediately after confirmed diagnosis, standardized pharmacological treatment with a combination of at least two or three antihypertensive drugs taken daily in a single tablet. Follow-up was conducted after one year to assess the percentage of adherence to treatment and achievement of blood pressure control targets (< 140/90 mmHg). Results: A total of 1490 patients were evaluated: 562 who followed the standardized and simplified protocol, and 928 who were treated with the usual protocol (family health centers: 650; family health centers: 278). After one year, patients in the standardized and simplified protocol group had a higher proportion of adherence to blood pressure control targets (65% versus 37% and 41%, p<0.001) and higher adherence to treatment compared to those following the usual protocol (71% versus 18% and 23%, p<0.001). Conclusions: The results show that the standardized and simplified protocol is more effective than the usual protocol in controlling arterial hypertension in patients undergoing treatment at the first level of care in Chile. Its implementation at the national level could contribute to a decrease in major cardiovascular events.

Objetivo: Avaliar a eficácia de um protocolo padronizado e simplificado, com base nos pilares técnicos da iniciativa HEARTS, para o controle de pacientes com hipertensão arterial do Programa de Saúde Cardiovascular na atenção primária à saúde do Chile. Métodos: Estudo observacional longitudinal (coorte histórica) em 2 centros de atenção primária de saúde da família em Santiago, que comparou o controle da pressão arterial em adultos com hipertensão, atingido com o protocolo padronizado e simplificado, versus o protocolo habitual, de acordo com as diretrizes nacionais. As inovações do protocolo padronizado incluíram mudanças na coordenação da equipe de saúde, início do tratamento farmacológico imediatamente após a confirmação do diagnóstico e tratamento farmacológico padronizado com associação de pelo menos 2 ou 3 anti-hipertensivos em um único comprimido, tomados uma vez ao dia. O acompanhamento foi realizado por 1 ano para avaliar o percentual de adesão ao tratamento e o cumprimento das metas de controle da pressão arterial (menor que 140/90 mmHg). Resultados: Foram avaliados 1.490 pacientes: 562 que utilizaram o protocolo padronizado e simplificado e 928 que foram tratados com o protocolo habitual (unidade de saúde da família 1: 650, unidade de saúde da família 2: 278). Em 1 ano de seguimento, os pacientes do grupo do protocolo padronizado e simplificado apresentaram maior proporção de cumprimento das metas de controle da pressão arterial (65% versus 37% e 41%, p<0,001) e maior percentual de adesão ao tratamento, em comparação com aqueles que utilizaram o protocolo habitual (71% versus 18% e 23%, p<0,001). Conclusões: Os resultados mostram que o protocolo padronizado e simplificado é mais eficaz que o protocolo habitual no controle da hipertensão arterial em pacientes que estão em tratamento na atenção primária do Chile. Sua implementação no nível nacional poderia contribuir para a redução de eventos cardiovasculares maiores.

Polycystin-1 Is a Crucial Regulator of BIN1 Expression and T-Tubule Remodeling Associated with the Development of Dilated Cardiomyopathy.

Cardiomyopathy is commonly observed in patients with autosomal dominant polycystic kidney disease (ADPKD), even when they have normal renal function and arterial pressure. The role of cardiomyocyte polycystin-1 (PC1) in cardiovascular pathophysiology remains unknown. PC1 is a potential regulator of BIN1 that maintains T-tubule structure, and alterations in BIN1 expression induce cardiac pathologies. We used a cardiomyocyte-specific PC1-silenced (PC1-KO) mouse model to explore the relevance of cardiomyocyte PC1 in the development of heart failure (HF), considering reduced BIN1 expression induced T-tubule remodeling as a potential mechanism. PC1-KO mice exhibited an impairment of cardiac function, as measured by echocardiography, but no signs of HF until 7-9 months of age. Of the PC1-KO mice, 43% died suddenly at 7 months of age, and 100% died after 9 months with dilated cardiomyopathy. Total BIN1 mRNA, protein levels, and its localization in plasma membrane-enriched fractions decreased in PC1-KO mice. Moreover, the BIN1 + 13 isoform decreased while the BIN1 + 13 + 17 isoform was overexpressed in mice without signs of HF. However, BIN1 + 13 + 17 overexpression was not observed in mice with HF. T-tubule remodeling and BIN1 score measured in plasma samples were associated with decreased PC1-BIN1 expression and HF development. Our results show that decreased PC1 expression in cardiomyocytes induces dilated cardiomyopathy associated with diminished BIN1 expression and T-tubule remodeling. In conclusion, positive modulation of BIN1 expression by PC1 suggests a novel pathway that may be relevant to understanding the pathophysiological mechanisms leading to cardiomyopathy in ADPKD patients.

Glutathione S-Transferase and Clusterin, New Players in the Ischemic Preconditioning Renal Protection in a Murine Model of Ischemia and Reperfusion.

BACKGROUND/AIMS: Renal ischemia and reperfusion injury (IRI) involves oxidative stress, disruption of microvasculature due to endothelial cell damage, loss of epithelial cell polarity secondary to cytoskeletal alterations, inflammation, and the subsequent transition into a mesenchymal phenotype. Ischemic preconditioning (IPC) has been proposed as a therapeutic strategy to avoid/ameliorate the IRI. Since previous results showed that IPC could have differential effects in kidney cortex vs. kidney medulla, in the present study we analyzed the effectiveness and molecular mechanisms implicated in IPC in both kidney regions. METHODS: We evaluated 3 experimental groups of BALB/c male mice: control (sham surgery); renal ischemia (30 min) by bilateral occlusion of the renal pedicle and reperfusion (48 hours) (I/R); and renal IPC (two cycles of 5 min of ischemia and 5 min of reperfusion) applied just before I/R. Acute kidney injury was evaluated by glomerular filtration rate (GFR), Neutrophil Gelatinase-Associated Lipocalin (NGAL) blood level, and histologic analysis. Oxidative stress was studied measurement the Glutathione S-Transferase (GST) activity, GSH/GSSG ratio, and lipoperoxidation levels. Inflammatory mediators (IL-1ß, IL-6, Foxp3, and IL-10) were quantified by qRT-PCR. The endothelial (PECAM-1), epithelial (AQP-1), mesenchymal (Vimentin, Fascin, and Hsp47), iNOS, clusterin, and Hsp27 expression were evaluated (qRT-PCR and/or Western blot). RESULTS: The IPC protocol prevented the decrease of GFR, reduced the plasma NGAL, and ameliorated morphological damage in the kidney cortex after I/R. The IPC also prevented the downregulation of GST activity, lipoperoxidation and ameliorated the oxidized glutathione. In addition, IPC prevented the upregulation of vimentin, fascin, and Hsp47, which was associated with the prevention of the downregulation of AQP1 after I/R. The protective effect of IPC was associated with the upregulation of Hsp27, Foxp3, and IL-10 expression in the renal cortex. However, the upregulation of iNOS, IL-1ß, IL-6, and clusterin by I/R were not modified by IPC. CONCLUSION: IPC conferred better protection in the kidney cortex as compared to the kidney medulla. The protective effect of IPC was associated with amelioration of oxidative stress, tubular damage, and the induction of markers of Treg lymphocytes activity in the cortical region. Further studies are needed to evaluate if lower tubular cell stress/damage after I/R may explain the preferential induction of Treg response in the kidney cortex induced by IPC.

Attended Automated Office Blood Pressure Measurement Versus Ambulatory Blood Pressure Monitoring in a Primary Healthcare Setting in Chile.

OBJECTIVES: As part of the HEARTS in the Americas initiative, Chilean primary healthcare centers have implemented novel hypertension management strategies, including new diagnostic approaches. This study evaluated the concordance between attended automated office blood pressure (AOBP) measurements with an oscillometric device and ambulatory blood pressure monitoring (ABPM). METHODS: This was an observational cohort study to evaluate and compare attended AOBP and ABPM for the diagnosis of hypertension in adults in a primary healthcare setting. RESULTS: The study evaluated 309 participants (54.2 ± 15.7 years; 50.5% male) from four primary healthcare centers in Santiago, Chile. Attended AOBP measurements were obtained at the clinic on two separate days, followed by ABPM. AOBP values indicated that 69.6% of patients had a systolic blood pressure (SBP) of ≥140 mm Hg and 34.6% had a diastolic blood pressure (DBP) of ≥90 mm Hg. A total of 83.5% had hypertension, 45.3% had high SBP, and 56.0% had high DBP. ABPM values indicated that 65.0% of patients had hypertension. The combined AOBP and ABPM analysis showed that 57.0% of patients had sustained hypertension, 26.5% had white coat hypertension, 8.1% had masked hypertension, and 8.4% were normotensive. The concordance between AOBP and ABPM (κ coefficient) was low (κ = 0.133; 95% confidence interval 0.028-0.237). The comparison of AOBP and ABPM measurements (Bland-Altman plots and bias calculations) showed an important bias in BP as measured using the AOBP method, especially for SBP (13.7 ± 11.6, 95% confidence interval -9.1 to 36.5). CONCLUSIONS: Attended AOBP alone may not be sufficient for adequate classification, diagnosis, and management of hypertension in Chile or other countries with similar demographics.

[Role of inflammation in hypertension]. / La inflamación en la hipertensión arterial, mecanismos de producción e implicancias terapéuticas.

Even though the mechanisms that mediate essential hypertension (HT) are not fully understood, an immunological-inflammatory mechanism could be the common pathway for diverse pathophysiological mechanisms. We analyze in a simplified way the participation of the immune system in HT. T lymphocytes (TL) and antigen presenting cells (APCs) are components of the immune system capable of generating proinflammatory cytokines. They cause endothelial damage, vasoconstriction, and decreased urinary sodium excretion. CD4+ and CD8+ TL are effector cells, causally implicated in the development of HT, whereas type γδ TL play their pathogenic role in HT enhancing endothelial dysfunction. Additionally, a immunomodulation decrease by regulatory TL, worsens endothelial dysfunction and reduces vasodilation in experimental HT. Results of recent studies indicate that lymphocyte activation would be mediated by antigens captured by antigen APCs for subsequent presentation to "naive" TL. On the other hand, proinflammatory states such as obesity, the change of the intestinal microbiota and the increase in salt intake favors TL and APC activation, contributing to HT development.

TRPM4 channel is involved in regulating epithelial to mesenchymal transition, migration, and invasion of prostate cancer cell lines.

Transient Receptor Potential Melastatin 4 (TRPM4) is a Ca2+ -activated and voltage-dependent monovalent cation channel, which depolarizes the plasma cell membrane, thereby modulating Ca2+ influx across Ca2+ -permeable pathways. TRPM4 is involved in different physiological processes such as T cell activation and the migration of endothelial and certain immune cells. Overexpression of this channel has been reported in various types of tumors including prostate cancer. In this study, a significant overexpression of TRPM4 was found only in samples from cancer with a Gleason score higher than 7, which are more likely to spread. To evaluate whether TRPM4 overexpression was related to the spreading capability of tumors, TRPM4 was knockdown by using shRNAs in PC3 prostate cancer cells and the effect on cellular migration and invasion was analyzed. PC3 cells with reduced levels of TRPM4 (shTRPM4) display a decrease of the migration/invasion capability. A reduction in the expression of Snail1, a canonical epithelial to mesenchymal transition (EMT) transcription factor, was also observed. Consistently, these cells showed a significant change in the expression of key EMT markers such as MMP9, E-cadherin/N-cadherin, and vimentin, indicating a partial reversion of the EMT process. Whereas, the overexpression of TRPM4 in LnCaP cells resulted in increased levels of Snail1, reduction in the expression of E-cadherin and increase in their migration potential. This study suggests a new and indirect mechanism of regulation of migration/invasion process by TRPM4 in prostate cancer cells, by inducing the expression of Snail1 gene and consequently, increasing the EMT.

l-NIL prevents the ischemia and reperfusion injury involving TLR-4, GST, clusterin, and NFAT-5 in mice.

On renal ischemia-reperfusion (I/R) injury, recruitment of neutrophils during the inflammatory process promotes local generation of oxygen and nitrogen reactive species, which, in turn, are likely to exacerbate tissue damage. The mechanism by which inducible nitric oxide synthase (iNOS) is involved in I/R has not been elucidated. In this work, the selective iNOS inhibitor l- N6-(1-iminoethyl)lysine (l-NIL) and the NOS substrate l-arginine were employed to understand the role of NOS activity on the expression of particular target genes and the oxidative stress elicited after a 30-min of bilateral renal ischemia, followed by 48-h reperfusion in Balb/c mice. The main findings of the present study were that pharmacological inhibition of iNOS with l-NIL during an I/R challenge of mice kidney decreased renal injury, prevented tissue loss of integrity, and improved renal function. Several novel findings regarding the molecular mechanism by which iNOS inhibition led to these protective effects are as follows: 1) a prevention of the I/R-related increase in expression of Toll-like receptor 4 (TLR-4), and its downstream target, IL-1ß; 2) reduced oxidative stress following the I/R challenge; noteworthy, this study shows the first evidence of glutathione S-transferase (GST) inactivation following kidney I/R, a phenomenon fully prevented by iNOS inhibition; 3) increased expression of clusterin, a survival autophagy component; and 4) increased expression of nuclear factor of activated T cells 5 (NFAT-5) and its target gene aquaporin-1. In conclusion, prevention of renal damage following I/R by the pharmacological inhibition of iNOS with l-NIL was associated with the inactivation of proinflammatory pathway triggered by TLR-4, oxidative stress, renoprotection (autophagy inactivation), and NFAT-5 signaling pathway.

Erythropoietin induces bone marrow and plasma fibroblast growth factor 23 during acute kidney injury.

It is accepted that osteoblasts/osteocytes are the major source for circulating fibroblast growth factor 23 (FGF23). However, erythropoietic cells of bone marrow also express FGF23. The modulation of FGF23 expression in bone marrow and potential contribution to circulating FGF23 has not been well studied. Moreover, recent studies show that plasma FGF23 may increase early during acute kidney injury (AKI). Erythropoietin, a kidney-derived hormone that targets erythropoietic cells, increases in AKI. Here we tested whether an acute increase of plasma erythropoietin induces FGF23 expression in erythropoietic cells of bone marrow thereby contributing to the increase of circulating FGF23 in AKI. We found that erythroid progenitor cells of bone marrow express FGF23. Erythropoietin increased FGF23 expression in vivo and in bone marrow cell cultures via the homodimeric erythropoietin receptor. In experimental AKI secondary to hemorrhagic shock or sepsis in rodents, there was a rapid increase of plasma erythropoietin, and an induction of bone marrow FGF23 expression together with a rapid increase of circulating FGF23. Blockade of the erythropoietin receptor fully prevented the induction of bone marrow FGF23 and partially suppressed the increase of circulating FGF23. Finally, there was an early increase of both circulating FGF23 and erythropoietin in a cohort of patients with severe sepsis who developed AKI within 48 hours of admission. Thus, increases in plasma erythropoietin and erythropoietin receptor activation are mechanisms implicated in the increase of plasma FGF23 in AKI.

The Ski Protein is Involved in the Transformation Pathway of Aurora Kinase A.

Oncogenic kinase Aurora A (AURKA) has been found to be overexpresed in several tumors including colorectal, breast, and hematological cancers. Overexpression of AURKA induces centrosome amplification and aneuploidy and it is related with cancer progression and poor prognosis. Here we show that AURKA phosphorylates in vitro the transcripcional co-repressor Ski on aminoacids Ser326 and Ser383. Phosphorylations on these aminoacids decreased Ski protein half-life. Reduced levels of Ski resulted in centrosomes amplification and multipolar spindles formation, same as AURKA overexpressing cells. Importantly, overexpression of Ski wild type, but not S326D and S383D mutants inhibited centrosome amplification and cellular transformation induced by AURKA. Altogether, these results suggest that the Ski protein is a target in the transformation pathway mediated by the AURKA oncogene.

Recent insights and therapeutic perspectives of angiotensin-(1-9) in the cardiovascular system.

Chronic RAS (renin-angiotensin system) activation by both AngII (angiotensin II) and aldosterone leads to hypertension and perpetuates a cascade of pro-hypertrophic, pro-inflammatory, pro-thrombotic and atherogenic effects associated with cardiovascular damage. In 2000, a new pathway consisting of ACE2 (angiotensin-converting enzyme2), Ang-(1-9) [angiotensin-(1-9)], Ang-(1-7) [angiotensin-(1-7)] and the Mas receptor was discovered. Activation of this novel pathway stimulates vasodilation, anti-hypertrophy and anti-hyperplasia. For some time, studies have focused mainly on ACE2, Ang-(1-7) and the Mas receptor, and their biological properties that counterbalance the ACE/AngII/AT1R (angiotensin type 1 receptor) axis. No previous information about Ang-(1-9) suggested that this peptide had biological properties. However, recent data suggest that Ang-(1-9) protects the heart and blood vessels (and possibly the kidney) from adverse cardiovascular remodelling in patients with hypertension and/or heart failure. These beneficial effects are not modified by the Mas receptor antagonist A779 [an Ang-(1-7) receptor blocker], but they are abolished by the AT2R (angiotensin type 2 receptor) antagonist PD123319. Current information suggests that the beneficial effects of Ang-(1-9) are mediated via the AT2R. In the present review, we summarize the biological effects of the novel vasoactive peptide Ang-(1-9), providing new evidence of its cardiovascular-protective activity. We also discuss the potential mechanism by which this peptide prevents and ameliorates the cardiovascular damage induced by RAS activation.

Influence of glucose metabolism on vascular smooth muscle cell proliferation.

Differentiation of vascular smooth muscle cells (VSMC) is an essential process of vascular development. VSMC have biosynthetic, proliferative, and contractile roles in the vessel wall. Alterations in the differentiated state of the VSMC play a critical role in the pathogenesis of atherosclerosis and intimal hyperplasia, as well as in a variety of other human diseases, including hypertension, asthma, atherosclerosis and vascular aneurysm. This review provides an overview of the current state of knowledge of molecular mechanisms involved in controlling VSMC proliferation, with particular focus on glucose metabolism and its relationship with mitochondrial bioenergetics. Increased levels of glucose transporter 1 (GLUT1) are observed in VSMC after endothelial injury, suggesting a relationship between glucose uptake and VSMC proliferation. Mitochondrial dysfunction is a common feature in VSMC during atherosclerosis. Alterations in mitochondrial function can be produced by dysregulation of mitofusin-2, a small GTPase associated with mitochondrial fusion. Moreover, exacerbated proliferation was observed in VSMC from pulmonary arteries with hyperpolarized mitochondria and enhanced glycolysis/glucose oxidation ratio. Several lines of evidence highlight the relevance of glucose metabolism in the control of VSMC proliferation, indicating a new area to be explored in the control of vascular pathogenesis.

A Combined Biomarker That Includes Plasma Fibroblast Growth Factor 23, Erythropoietin, and Klotho Predicts Short- and Long-Term Morbimortality and Development of Chronic Kidney Disease in Critical Care Patients with Sepsis: A Prospective Cohort.

Acute Kidney Injury (AKI) is a frequent complication in intensive care unit (ICU) patients that increases mortality and chronic kidney disease (CKD) development. AKI is associated with elevated plasma fibroblast growth factor 23 (FGF23), which can be modulated by erythropoietin (EPO) and Klotho. We aimed to evaluate whether a combined biomarker that includes these molecules predicted short-/long-term outcomes. We performed a prospective cohort of ICU patients with sepsis and previously normal renal function. They were followed during their inpatient stay and for one year after admission. We measured plasma FGF23, EPO, and Klotho levels at admission and calculated a combined biomarker (FEK). A total of 164 patients were recruited. Of these, 50 (30.5%) had AKI at admission, and 55 (33.5%) developed AKI within 48 h. Patients with AKI at admission and those who developed AKI within 48 h had 12- and 5-fold higher FEK values than non-AKI patients, respectively. Additionally, patients with higher FEK values had increased 1-year mortality (41.9% vs. 18.6%, p = 0.003) and CKD progression (26.2% vs. 8.3%, p = 0.023). Our data suggest that the FEK indicator predicts the risk of AKI, short-/long-term mortality, and CKD progression in ICU patients with sepsis. This new indicator can improve clinical outcome prediction and guide early therapeutic strategies.

High Plasma Levels of Fibroblast Growth Factor 23 Are Associated with Increased Risk of COVID-19 in End-Stage Renal Disease Patients on Hemodialysis: Results of a Prospective Cohort.

End-stage renal disease (ESRD) patients are a population with high rates of COVID-19 and mortality. These patients present a low response to anti-SARS-CoV-2 immunization, which is associated with immune dysfunction. ESRD patients also present high plasma titers of Fibroblast Growth Factor 23 (FGF23), a protein hormone that reduces immune response in vivo and in vitro. Increased FGF23 levels associate with higher infection-related hospitalizations and adverse infectious outcomes. Thus, we evaluated whether ESRD patients with high FGF23 titers have an increased rate of SARS-CoV-2 infection. METHODS: We performed a prospective cohort of ESRD patients in hemodialysis who had measurements of plasma intact FGF23 in 2019. We determined COVID-19 infections, hospitalizations, and mortality between January 2020 and December 2021. RESULTS: We evaluated 243 patients. Age: 60.4 ± 10.8 years. Female: 120 (49.3%), diabetes: 110 (45.2%). During follow-up, 45 patients developed COVID-19 (18.5%), 35 patients were hospitalized, and 12 patients died (mortality rate: 26.6%). We found that patients with higher FGF23 levels (defined as equal or above median) had a higher rate of SARS-CoV-2 infection versus those with lower levels (18.8% versus 9.9%; Hazard ratio: 1.92 [1.03-3.56], p = 0.039). Multivariate analysis showed that increased plasma FGF23 was independently associated with SARS-CoV-2 infection and severe COVID-19. DISCUSSION: Our results suggest that high plasma FGF23 levels are a risk factor for developing COVID-19 in ESRD patients. These data support the potential immunosuppressive effects of high circulating FGF23 as a factor implicated in the association with worse clinical outcomes. Further data are needed to confirm this hypothesis.

Nephrologists' perspectives on the impact of COVID-19 on caring for patients undergoing dialysis in Latin America: a qualitative study.

OBJECTIVE: To describe the experiences of nephrologists on caring for patients undergoing in-centre haemodialysis during the COVID-19 pandemic in Latin America. DESIGN: Twenty-five semistructured interviews were conducted by Zoom videoconference in English and Spanish languages during 2020 until data saturation. Using thematic analysis, we conducted line-by-line coding to inductively identify themes. SETTING: 25 centres across nine countries in Latin America. PARTICIPANTS: Nephrologists (17 male and 8 female) were purposively sampled to include diverse demographic characteristics and clinical experience. RESULTS: We identified five themes: shock and immediate mobilisation for preparedness (overwhelmed and distressed, expanding responsibilities to manage COVID-19 infection and united for workforce resilience); personal vulnerability (being infected with COVID-19 and fear of transmitting COVID-19 to family); infrastructural susceptibility of dialysis units (lacking resources and facilities for quarantine, struggling to prevent cross-contamination, and depletion of personal protective equipment and cleaning supplies); helplessness and moral distress (being forced to ration life-sustaining equipment and care, being concerned about delayed and shortened dialysis sessions, patient hesitancy to attend to dialysis sessions, being grieved by socioeconomic disparities, deterioration of patients with COVID-19, harms of isolation and inability to provide kidney replacement therapy); and fostering innovative delivery of care (expanding use of telehealth, increasing uptake of PD and shifting focus on preventing syndemics). CONCLUSION: Nephrologists felt personally and professionally vulnerable and reported feeling helpless and morally distressed because they doubted their capacity to provide safe care for patients undergoing dialysis. Better availability and mobilisation of resources and capacities to adapt models of care, including telehealth and home-based dialysis, are urgently needed.

Aldosterone promotes autoimmune damage by enhancing Th17-mediated immunity.

Excessive production of aldosterone leads to the development of hypertension and cardiovascular disease by generating an inflammatory state that can be promoted by T cell immunity. Because nature and intensity of T cell responses is controlled by dendritic cells (DCs), it is important to evaluate whether the function of these cells can be modulated by aldosterone. In this study we show that aldosterone augmented the activation of CD8(+) T cells in a DC-dependent fashion. Consistently, the mineralocorticoid receptor was expressed by DCs, which showed activation of MAPK pathway and secreted IL-6 and TGF-beta in response to aldosterone. In addition, DCs stimulated with aldosterone impose a Th17 phenotype to CD4(+) T cells, which have recently been associated with the promotion of inflammatory and autoimmune diseases. Accordingly, we observed that aldosterone enhances the progression of experimental autoimmune encephalomyelitis, an autoimmune disease promoted by Th17 cells. In addition, blockade of the mineralocorticoid receptor prevented all aldosterone effects on DCs and attenuated experimental autoimmune encephalomyelitis development in aldosterone-treated mice. Our data suggest that modulation of DC function by aldosterone enhances CD8(+) T cell activation and promotes Th17-polarized immune responses, which might contribute to the inflammatory damage leading to hypertension and cardiovascular disease.

Low 2-methoxyestradiol levels at the first trimester of pregnancy are associated with the development of pre-eclampsia.

OBJECTIVE: To determine whether maternal plasma levels of 2-methoxyestradiol (2-ME) are decreased early in pregnancies that subsequently develop pre-eclampsia (PE) and whether this difference could be attributed to the presence of Val158Met catechol-O-methyltransferase (COMT) polymorphism in the placenta. METHODS: Clinical characteristics and plasma samples were collected at 11 to 14 weeks prospectively in a cohort of patients. From them, 13 PE and 72 control pregnant women were chosen. Plasma soluble fms-like tyrosine kinase1 and placental growth factor levels were measured by electrochemiluminescence and 2-ME was measured by high-performance liquid chromatography with mass spectrometry/mass spectrometry detection. At delivery, placental tissue was collected and the Val158Met COMT polymorphism was determined by restriction fragment length polymorphism-PCR. RESULTS: At 11 to 14 weeks, patients who would develop PE have significantly lower plasma levels of 2-ME than controls [1.9 ± 2 standard error of the mean (SEM) vs 61.7 ± 27 pg/mL, P < 0.05]. The Val158Met polymorphism was more frequent in controls than in PE patients and the placental presence of COMT polymorphism was associated with a decreased risk of developing PE [PE: 23.1% vs control: 66.6%; χ(2) = 10.9, p = 0.0041]. CONCLUSIONS: Lower plasma concentrations of 2-ME during early pregnancy in patients who subsequently develop PE were found. Presence of placental Val158Met COMT polymorphism is associated with a decreased risk to develop PE, suggesting a protective role against PE.

IL-17A levels increase in the infarcted region of the left ventricle in a rat model of myocardial infarction.

Th17 cells, a recently described subtype of CD4+ effector lymphocytes, have been linked to cell-mediated autoimmune and inflammatory diseases as well as to cardiovascular diseases. However, the participation of IL-17A in myocardial ischemic injury has not been clearly defined. We therefore conducted the present study to evaluate IL-17A and Th17-related cytokine levels in a rat model of myocardial infarction (MI). MI was induced in male Sprague Dawley rats by coronary artery ligation. Controls were sham-operated (Sh) or non-operated (C). Blood and samples from the left ventricle (LV) were collected at weeks 1 and 4 post-MI. At week 1, MI animals exhibited increased IL-6, IL-23 and TGF-ß mRNA levels with no apparent change in IL-17 mRNA or protein levels in whole LV. Only TGF-ß mRNA remained elevated at week 4 post-MI. However, further analysis revealed that IL-17A mRNA and protein levels as well as IL-6 and IL-23 mRNA were indeed increased in the infarcted region, though not in the remote non infarcted region of the LV, except for IL-23 mRNA. The increased expression of IL-17A and Th17-related cytokines in the infarcted region of LV, suggests that this proinflammatory pathway might play a role in early stages of post MI cardiac remodelling.

[Assessment of arterial damage by noninvasive peripheral arterial tonometry in non-diabetic hemodialysis patients]. / Daño arterial asociado a la enfermedad renal crónica: evaluación mediante técnicas de laboratorio no invasivo en pacientes hemodializados.

BACKGROUND: Hemodialysis patients (HD) display high rates of cardiac disease and mortality. The cardiovascular morbidity and mortality of HD patients is attributable in a significant proportion to endothelial dysfunction, arterial stiffness, and vascular calcifications. AIM: To measure vascular reactivity in HD subjects and compare them with healthy volunteers. MATERIAL AND METHODS: Forty eight non diabetic patients aged 58 ± 4.6 years (29 males) on hemodialysis for a mean lapse of 4.8 years were studied. Arterial stiffness was measured in the radial artery. Pulse wave velocity was measured by noninvasive peripheral arterial tonometry in carotid and femoral arteries. Endothelial function was assessed, measuring reactive hyperemia response after a 5 min period of ischemia. As a control, all values were also measured in age and gender-matched healthy volunteers. RESULTS: Arterial stiffness was significantly higher in HD patients than controls (23.9 ± 3.3 and 18.4 ± 3.4% respectively, p < 0.05). HD subjects had an increased pulse wave velocity (10.0 ± 0.8 and 7.6 ± 0.9 m/s respectively, p < 0.05). A reduction in the change in pulse amplitude pressure, as a measure of arterial dysfunction, was only observed in male patients (1.7 ± 0.4 and 2.7 ± 0.4 respectively p < 0.01). CONCLUSIONS: Noninvasive assessment of peripheral vascular function may be useful for the identification of patients at risk for late cardiac events.