Endothelial dysfunction and cardiovascular disease in early-stage chronic kidney disease: cause or association?

Mild renal impairment is associated with increased cardiovascular events and all-cause mortality following cancer diagnosis

BACKGROUND

The association between mildly decreased renal function and cardiovascular (CV) outcomes in cancer patients remains unestablished.

AIMS

We sought to explore this association in asymptomatic self-referred healthy adults.

METHOD

We followed 25, 274 adults, aged 40-79 years, who were screened in preventive healthcare settings. Participants were free of CV disease or cancer at baseline. The estimated glomerular filtration rate (eGFR) was calculated according to the CKD Epidemiology Collaboration equation and categorized into groups [≤59, 60-69, 70-79, 80-89, 90-99, ≥100 (ml/min/1.73 m²)]. The outcome included a composite of death, acute coronary syndrome, or stroke, examined using a Cox model with cancer as a time-dependent variable.

RESULTS

Mean age at baseline was 50 ± 8 years and 7973 (32%) were women. During a median follow-up of 6 years (interquartile range: 3-11), 1879 (7.4%) participants were diagnosed with cancer, of them 504 (27%) develop the composite outcome and 82 (4%) presented with CV events. Multivariable time-dependent analysis showed an increased risk of 1.6, 1.4, and 1.8 for the composite outcome among individuals with eGFR of 90-99 [95% confidence interval (CI): 1.2-2.1 P = 0.01], 80-89 (95% CI: 1.1-1.9, P = 0.01) and 70-79 (95% CI: 1.4-2.3, P < 0.001), respectively. The association between eGFR and the composite outcome was modified by cancer with 2.7-2.9 greater risk among cancer patients with eGFR of 90-99 and 80-89 but not among individuals free from cancer ( Pinteraction < 0.001).

CONCLUSION

Patients with mild renal impairment are at high risk for CV events and all-cause mortality following cancer diagnosis. eGFR evaluation should be considered in the CV risk assessment of cancer patients.

Association of Chronic Kidney Disease with Cardiovascular Disease in Cancer Patients: A Cross-Sectional Study

INTRODUCTION

Due to the cardiotoxicity of cancer treatment and traditional risk factors for cardiovascular disease (CVD) such as obesity, diabetes, dyslipidemia, and hypertension, cancer patients are at higher risk of developing CVD. However, limited research exists on the correlation between chronic kidney disease (CKD) and CVD risk in cancer patients.

METHODS

This cross-sectional study selected cancer patients aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES) conducted from 2015 to 2020. Multivariable logistic regression was used to assess the association between CKD and CVD in cancer patients. Additionally, subgroup analyses were conducted to investigate the association among different groups of cancer patients.

RESULTS

We included 1,700 adult cancer patients (52.53% were females). After multivariable adjustment for covariates including traditional CVD factors, CKD was significantly associated with CVD, with an odds ratio (95% confidence interval) and p value of 1.61 (1.18, 2.19) and 0.004. Subgroup analyses after multivariable adjustment showed a significant correlation between CKD and increased CVD risk in the following cancer patients: age ≥60 years, males, white ethnicity, and individuals with or without traditional CVD factors (obesity, diabetes, dyslipidemia, and hypertension).

CONCLUSIONS

CKD remains a significant factor in the higher risk of CVD among adult cancer patients in the United States, even after adjustment for traditional CVD risk factors. Therefore, to reduce the risk of CVD in cancer patients, it is important to treat CKD as a non-traditional risk factor for CVD and actively manage it.

Removal of calciprotein particles from the blood using an adsorption column improves prognosis of hemodialysis miniature pigs

Hyperphosphatemia is a major risk for poor prognosis in patients with end-stage renal disease. However, the molecular mechanism behind this link remains elusive. We and others have demonstrated that serum phosphorus levels correlate positively with circulating levels of calciprotein particles (CPPs). CPPs are colloidal mineral-protein complexes containing insoluble calcium-phosphate precipitates and have been reported to induce calcification in cultured vascular smooth muscle cells and inflammatory responses in cultured macrophages. Hence, we hypothesize that CPPs may be responsible for disorders associated with hyperphosphatemia. Using hyperphosphatemic miniature pigs receiving hemodialysis, here we show that removal of CPPs from the blood with a newly developed CPP adsorption column improves survival and alleviates complications including coronary artery calcification, vascular endothelial dysfunction, metastatic pulmonary calcification, left ventricular hypertrophy, and chronic inflammation. The present study identifies CPPs as an effective therapeutic target and justifies clinical trials to determine whether the CPP adsorption column may be useful as a medical device for improving clinical outcomes of hemodialysis patients.

Mitochondrial dysfunction in the pathogenesis of endothelial dysfunction

Cardiovascular diseases (CVDs) are a matter of concern worldwide, and mitochondrial dysfunction is one of the major contributing factors. Vascular endothelial dysfunction has a major role in the development of atherosclerosis because of the abnormal chemokine secretion, inflammatory mediators, enhancement of LDL oxidation, cytokine elevation, and smooth muscle cell proliferation. Endothelial cells transfer oxygen from the pulmonary circulatory system to the tissue surrounding the blood vessels, and a majority of oxygen is transferred to the myocardium by endothelial cells, which utilise a small amount of oxygen to generate ATP. Free radicals of oxide are produced by mitochondria, which are responsible for cellular oxygen uptake. Increased mitochondrial ROS generation and reduction in agonist-stimulated eNOS activation and nitric oxide bioavailability were directly linked to the observed change in mitochondrial dynamics, resulting in various CVDs and endothelial dysfunction. Presently, the manuscript mainly focuses on endothelial dysfunction, providing a deep understanding of the various features of mitochondrial mechanisms that are used to modulate endothelial dysfunction. We talk about recent findings and approaches that may make it possible to detect mitochondrial dysfunction as a potential biomarker for risk assessment and diagnosis of endothelial dysfunction. In the end, we cover several targets that may reduce mitochondrial dysfunction through both direct and indirect processes and assess the impact of several different classes of drugs in the context of endothelial dysfunction.

High circulating endocan in chronic kidney disease? A systematic review and meta-analysis

BACKGROUND

Chronic kidney disease (CKD) is one of the leading causes of morbidity and mortality worldwide. Endothelial dysfunction has been suggested to be involved in the pathophysiology of CKD. Endocan, as an endothelial factor, has been shown to increase in several diseases. The current systematic review and meta-analysis was performed with the aim of determining the association between endocan levels and CKD.

METHODS

Four international databases, including PubMed, Embase, Scopus, and Web of Science were searched for relevant studies. Afterward, screening and extraction of data were performed. We conducted a random-effect meta-analysis to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) to compare circulating endocan levels between patients with CKD (including patients undergoing hemodialysis) and healthy controls. Subgroup analysis based on the specimen in which endocan was measured (serum or plasma) was also performed.

RESULTS

After screening by title/abstract and full-text review by the authors, 20 studies were included. Meta-analysis revealed that serum endocan is higher in CKD patients compared to healthy controls (SMD 1.34, 95% CI 0.20 to 2.48, p-value<0.01). This higher endocan level was also observed in the subgroup of studies that measured plasma endocan while this was not the case for the subgroup of studies assessing serum endocan. Meta-analysis was also performed for comparison of CKD patients without other comorbidities and healthy controls, which resulted in the same conclusion of higher endocan levels in patients with CKD (SMD 0.74, 95% CI 0.52 to 0.95, p-value<0.01). Moreover, endocan was associated with cardiovascular diseases in CKD.

CONCLUSION

Our study demonstrated that endocan is significantly increased in patients with CKD. This can have clinical implications as well as highlight the need for future research investigating the diagnostic and prognostic role of endocan in CKD.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

The effect of isovitexin on lipopolysaccharide-induced renal injury and inflammation by induction of protective autophagy

Chronic kidney disease (CKD) is a systemic inflammatory syndrome that includes tubulointerstitial inflammation. Lipopolysaccharide (LPS), the outer membrane of Gram-negative bacteria, can increase reactive oxygen species production (ROS) that triggers cell inflammation. Isovitexin (IV) is a flavone that has the potential for anticancer, antioxidant, and anti-inflammatory. This study aimed to hypothesize that IV inhibited LPS-induced renal injury in vitro and in vivo. In vitro study, IV prevented LPS-induced ROS production and increased cell viability on SV40-MES-13 cells. Additionally, IV ameliorated mitochondrial membrane potential, downregulated inflammation and pyroptosis factors on LPS treatment. We found that LPS treatment reduced the expression of autophagy, however, this effect was reversed by IV. In vivo study, the renal injury model in C57BL/6 mice cotreatment with IV was examined. In addition, IV decreased LPS-induced glomerular atrophy and reduced inflammation-related cytokines releases. Further showed that IV could significantly reduce LPS-induced inflammation and pyroptosis factors in mice. Under the immunostaining, increased fluorescence of LC3 autophagy-related protein was recovered by IV. In summary, IV ameliorated renal injury, inflammation and increased protected autophagy by anti-ROS production, anti-inflammation, and anti-pyroptosis. In the future, the safety of isovitexin as a novel perspective for CKD patients should be evaluated in further clinical studies.

Mineralocorticoid receptor antagonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease

Diabetic kidney disease (DKD) develops in ∼40% of patients with diabetes and is the most common cause of chronic kidney disease (CKD) worldwide. Patients with CKD, especially those with diabetes mellitus, are at high risk of both developing kidney failure and cardiovascular (CV) death. The use of renin-angiotensin system (RAS) blockers to reduce the incidence of kidney failure in patients with DKD dates back to studies that are now ≥20 years old. During the last few years, sodium-glucose co-transporter-2 inhibitors (SGLT2is) have shown beneficial renal effects in randomized trials. However, even in response to combined treatment with RAS blockers and SGLT2is, the renal residual risk remains high with kidney failure only deferred, but not avoided. The risk of CV death also remains high even with optimal current treatment. Steroidal mineralocorticoid receptor antagonists (MRAs) reduce albuminuria and surrogate markers of CV disease in patients already on optimal therapy. However, their use has been curtailed by the significant risk of hyperkalaemia. In the FInerenone in reducing kiDnEy faiLure and dIsease prOgression in DKD (FIDELIO-DKD) study comparing the actions of the non-steroidal MRA finerenone with placebo, finerenone reduced the progression of DKD and the incidence of CV events, with a relatively safe adverse event profile. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of MRAs, analyses the potential mechanisms involved and discusses their potential future place in the treatment of patients with diabetic CKD.

Hypertension in kidney transplant recipients

Kidney transplantation is considered the treatment of choice for end-stage kidney disease patients. However, the residual cardiovascular risk remains significantly higher in kidney transplant recipients (KTRs) than in the general population. Hypertension is highly prevalent in KTRs and represents a major modifiable risk factor associated with adverse cardiovascular outcomes and reduced patient and graft survival. Proper definition of hypertension and recognition of special phenotypes and abnormal diurnal blood pressure (BP) patterns is crucial for adequate BP control. Misclassification by office BP is commonly encountered in these patients, and a high proportion of masked and uncontrolled hypertension, as well as of white-coat hypertension, has been revealed in these patients with the use of ambulatory BP monitoring. The pathophysiology of hypertension in KTRs is multifactorial, involving traditional risk factors, factors related to chronic kidney disease and factors related to the transplantation procedure. In the absence of evidence from large-scale randomized controlled trials in this population, BP targets for hypertension management in KTR have been extrapolated from chronic kidney disease populations. The most recent Kidney Disease Improving Global Outcomes 2021 guidelines recommend lowering BP to less than 130/80 mmHg using standardized BP office measurements. Dihydropyridine calcium channel blockers and angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers have been established as the preferred first-line agents, on the basis of emphasis placed on their favorable outcomes on graft survival. The aim of this review is to provide previous and recent evidence on prevalence, accurate diagnosis, pathophysiology and treatment of hypertension in KTRs.

Insulin Resistance Is Cheerfully Hitched with Hypertension

Cardiovascular diseases and type 2 diabetes mellitus (T2DM) have risen steadily worldwide, particularly in low-income and developing countries. In the last hundred years, deaths caused by cardiovascular diseases increased rapidly to 35–40%, becoming the most common cause of mortality worldwide. Cardiovascular disease is the leading cause of morbidity and mortality in type 2 diabetes mellitus (T2DM), which is aggravated by hypertension. Hypertension and diabetes are closely interlinked since they have similar risk factors such as endothelial dysfunction, vascular inflammation, arterial remodeling, atherosclerosis, dyslipidemia, and obesity. Patients with high blood pressure often show insulin resistance and have a higher risk of developing diabetes than normotensive individuals. It has been observed that over the last 30 years, the prevalence of insulin resistance (IR) has increased significantly. Accordingly, hypertension and insulin resistance are strongly related to an increased risk of impaired glucose tolerance, diabetes, cardiovascular diseases (CVD), and endocrine disorders. Common mechanisms, for instance, upregulation of the renin–angiotensin–aldosterone system, oxidative stress, inflammation, and activation of the immune system, possibly have a role in the association between diabetes and hypertension. Altogether these abnormalities significantly increase the risk of developing type 2 diabetes.

Combination of High-Density Lipoprotein Cholesterol and Lipoprotein(a) as a Predictor of Collateral Circulation in Patients With Severe Unilateral Internal Carotid Artery Stenosis or Occlusion

BACKGROUND AND PURPOSE

Collateral circulation is considered an important factor affecting the risk of stroke, but the factors that affect collateral circulation remain unclear. This study was performed to identify the factors associated with collateral circulation, especially blood lipids.

METHODS

The study involved patients who had undergone digital subtraction angiography and were confirmed as having severe unilateral stenosis or occlusion of the internal carotid artery (ICA). We classified the collateral circulation status of each patient as good (Grade 3 or 4) or poor (Grade 0, 1, or 2) according to the grading system of the American Society of Interventional and Therapeutic Neuroradiology/American Society of Interventional Radiology. We collected data on patients' characteristics and identified the factors that affect collateral circulation.

RESULTS

This study included 212 patients. The multivariate logistic regression analysis showed that the high-density lipoprotein cholesterol (HDL-C) concentration and a complete anterior half of the circle of Willis were independent protective factors for good collateral circulation, whereas elevated lipoprotein(a) [Lp(a)] and serum creatinine concentrations were independent risk factors for good collateral circulation. The area under the receiver operating characteristics curve (AUC) was 0.68 (95% confidence interval [CI], 0.61-0.76) for HDL-C and 0.69 (95% CI, 0.62-0.76) for Lp(a). A binary logistic regression model analysis of the joint factor of HDL-C and Lp(a) yielded an AUC of 0.77 (95% CI, 0.71-0.84).

CONCLUSIONS

In patients with severe unilateral ICA stenosis or occlusion, the combination of HDL-C and Lp(a) is a useful predictor of collateral circulation.

Role of hypertension in kidney transplant recipients

Cardiovascular events are one of the leading causes of mortality in kidney transplant recipients. Hypertension is the most common comorbidity accompanying chronic kidney disease, with prevalence remaining as high as 90% even after kidney transplantation. It is often poorly controlled. Abnormal blood pressure profiles, such as masked or white-coat hypertension, are also extremely common in these patients. The pathophysiology of blood pressure elevation in kidney transplant recipients is complex and includes transplantation-specific risk factors, which are added to the traditional or chronic kidney disease-related factors. Despite these observations, hypertension management has been an under-researched area in kidney transplantation. Thus, relevant evidence derives either from studies in the general population or from small trials in kidney transplant recipients. Based on the relevant guidelines in the general population, lifestyle modifications should probably be applied as the first step of hypertension management in kidney transplant recipients. The optimal pharmacological management of hypertension in kidney transplant recipients is also not clear. Dihydropyridine calcium channel blockers are commonly used as first line agents because of their lack of adverse effects on the kidney, while other antihypertensive drug classes are under-utilised due to fear of the possible haemodynamic consequences on renal function. This review summarizes the existing data on the pathophysiology, diagnosis, prognostic significance and management of hypertension in kidney transplantation.

Association of kidney functions with a cascade of care for diabetes and hypertension in two geographically distinct Indian cohorts

AIM

Type 2 diabetes (T2DM) and hypertension (HTN) are the main modifiable risk factors of chronic kidney disease (CKD), among the known traditional and non-traditional risk factors.

METHODS

We determined the prevalence and care-cascade of these modifiable CKD-risk factors and their association with socioeconomic status in adjoining Lucknow and Puducherry cities of India.

RESULTS

439 participants reported no CKD were recruited. Serum analysis revealed an Estimated Glomerular Filtration Rate (eGFR) ≥ 90 ml/min/1.73 m² in 60.36% of the population. Of them, 55.85% had HTN and/or T2DM as CKD-risk factors; however, less than half of this population was unaware of their CKD-risk status. Awareness and treatment were significantly higher in Puducherry and were associated with literacy, occupation, and residence place. Although the CKD-risk population was about two times higher in Puducherry than Lucknow, the populations with mild-low eGFR were comparable in the two regions. Moreover, in Lucknow, mild-low eGFR and low awareness were more prevalent among the younger participants (<30 years), relative to Puducherry.

CONCLUSIONS

Despite a higher prevalence of CKD-risk factors in Puducherry, populations with mild-low eGFR were comparable to Lucknow. More heightened awareness and better care cascade for CKD-risk factors in Puducherry may prevent or delay eGFR reduction.

Trimethylamine N-oxide mediated Y-box binding protein-1 nuclear translocation promotes cell cycle progression by directly downregulating Gadd45a expression in a cellular model of chronic kidney disease

AIMS

Cell cycle arrest plays critical roles in preventing renal tubular epithelial cell (RTEC) injury and maladaptation after the onset of chronic kidney disease (CKD), but the underlying mechanism governing this arrest has not been fully elucidated. This study was designed to determine the underlying role of YB-1 in promoting cell cycle progression and nuclear translocation in HK-2 cells induced by trimethylamine N-oxide (TMAO).

MAIN METHODS

YB-1 primarily accumulated in the cytoplasm in HK-2 cells after they were treated with TMAO for 30 min and 6 h. Gene expression was analysed using RNA sequencing in HK-2 cells treated with TMAO. Cell cycle progression was analysed via flow cytometry. Luciferase assay and ChIP-PCR were performed to determine the relationship between transcription factor YB-1 and Gadd45a promoter region. Additionally, mice were fed with TMAO to test renal dysfunction and measure the expression of YB-1, GADD45a and CCNA2 in the kidney sections through immunohistochemistry.

KEY FINDINGS

YB-1 primarily accumulated in the cytoplasm in HK-2 cells after they were treated with TMAO for 30 min and 6 h. RNA sequencing analysis showed that the cell cycle checkpoint genes growth arrest and DNA damage (Gadd)45a, Gadd45g, cyclin (Ccn)a2, Ccnb1, Ccne1 and Ccnf were differentially expressed in HK-2 cells after treated with 400 μM TMAO for 30 min. Flow cytometry results demonstrated that cell cycle progression was blocked at the G2/M checkpoint. In animal models, elevated dietary TMAO directly led to progressive renal tubulointerstitial dysfunction and inhibited the expression of YB-1 in kidney. Moreover, YB-1 was determined to regulate Gadd45a expression by directly binding to its promoter region. YB-1 expression was negatively correlated with the expression of Gadd45a and Gadd45g but positively correlated with Ccna2, Ccnb1, Ccne1 and Ccnf in CKD.

SIGNIFICANCE

YB-1 may be a reliable molecular target and an effective prognostic biomarker for CKD.

Regulation of miRNAs by Natural Antioxidants in Cardiovascular Diseases: Focus on SIRT1 and eNOS

Cardiovascular diseases (CVDs) are the most common cause of morbidity and mortality worldwide. The potential benefits of natural antioxidants derived from supplemental nutrients against CVDs are well known. Remarkably, natural antioxidants exert cardioprotective effects by reducing oxidative stress, increasing vasodilation, and normalizing endothelial dysfunction. Recently, considerable evidence has highlighted an important role played by the synergistic interaction between endothelial nitric oxide synthase (eNOS) and sirtuin 1 (SIRT1) in the maintenance of endothelial function. To provide a new perspective on the role of natural antioxidants against CVDs, we focused on microRNAs (miRNAs), which are important posttranscriptional modulators in human diseases. Several miRNAs are regulated via the consumption of natural antioxidants and are related to the regulation of oxidative stress by targeting eNOS and/or SIRT1. In this review, we have discussed the specific molecular regulation of eNOS/SIRT1-related endothelial dysfunction and its contribution to CVD pathologies; furthermore, we selected nine different miRNAs that target the expression of eNOS and SIRT1 in CVDs. Additionally, we have summarized the alteration of miRNA expression and regulation of activities of miRNA through natural antioxidant consumption.

Improved Detection of Potentially Pleiotropic Genes in Coronary Artery Disease and Chronic Kidney Disease Using GWAS Summary Statistics

The coexistence of coronary artery disease (CAD) and chronic kidney disease (CKD) implies overlapped genetic foundation. However, the common genetic determination between the two diseases remains largely unknown. Relying on summary statistics publicly available from large scale genome-wide association studies (n = 184,305 for CAD and n = 567,460 for CKD), we observed significant positive genetic correlation between CAD and CKD (r_g = 0.173, p = 0.024) via the linkage disequilibrium score regression. Next, we implemented gene-based association analysis for each disease through MAGMA (Multi-marker Analysis of GenoMic Annotation) and detected 763 and 827 genes associated with CAD or CKD (FDR < 0.05). Among those 72 genes were shared between the two diseases. Furthermore, by integrating the overlapped genetic information between CAD and CKD, we implemented two pleiotropy-informed informatics approaches including cFDR (conditional false discovery rate) and GPA (Genetic analysis incorporating Pleiotropy and Annotation), and identified 169 and 504 shared genes (FDR < 0.05), of which 121 genes were simultaneously discovered by cFDR and GPA. Importantly, we found 11 potentially new pleiotropic genes related to both CAD and CKD (i.e., ARHGEF19, RSG1, NDST2, CAMK2G, VCL, LRP10, RBM23, USP10, WNT9B, GOSR2, and RPRML). Five of the newly identified pleiotropic genes were further repeated via an additional dataset CAD available from UK Biobank. Our functional enrichment analysis showed that those pleiotropic genes were enriched in diverse relevant pathway processes including quaternary ammonium group transmembrane transporter, dopamine transport. Overall, this study identifies common genetic architectures overlapped between CAD and CKD and will help to advance understanding of the molecular mechanisms underlying the comorbidity of the two diseases.

Finerenone and Cardiovascular Outcomes in Patients With Chronic Kidney Disease and Type 2 Diabetes

Supplemental Digital Content is available in the text.

Background:

The FIDELIO-DKD trial (Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease) evaluated the effect of the nonsteroidal, selective mineralocorticoid receptor antagonist finerenone on kidney and cardiovascular outcomes in patients with chronic kidney disease and type 2 diabetes with optimized renin–angiotensin system blockade. Compared with placebo, finerenone reduced the composite kidney and cardiovascular outcomes. We report the effect of finerenone on individual cardiovascular outcomes and in patients with and without history of atherosclerotic cardiovascular disease (CVD).

Methods:

This randomized, double-blind, placebo-controlled trial included patients with type 2 diabetes and urine albumin-to-creatinine ratio 30 to 5000 mg/g and an estimated glomerular filtration rate ≥25 to <75 mL per min per 1.73 m², treated with optimized renin–angiotensin system blockade. Patients with a history of heart failure with reduced ejection fraction were excluded. Patients were randomized 1:1 to receive finerenone or placebo. The composite cardiovascular outcome included time to cardiovascular death, myocardial infarction, stroke, or hospitalization for heart failure. Prespecified cardiovascular analyses included analyses of the components of this composite and outcomes according to CVD history at baseline.

Results:

Between September 2015 and June 2018, 13 911 patients were screened and 5674 were randomized; 45.9% of patients had CVD at baseline. Over a median follow-up of 2.6 years (interquartile range, 2.0–3.4 years), finerenone reduced the risk of the composite cardiovascular outcome compared with placebo (hazard ratio, 0.86 [95% CI, 0.75–0.99]; P=0.034), with no significant interaction between patients with and without CVD (hazard ratio, 0.85 [95% CI, 0.71–1.01] in patients with a history of CVD; hazard ratio, 0.86 [95% CI, 0.68–1.08] in patients without a history of CVD; P value for interaction, 0.85). The incidence of treatment-emergent adverse events was similar between treatment arms, with a low incidence of hyperkalemia-related permanent treatment discontinuation (2.3% with finerenone versus 0.8% with placebo in patients with CVD and 2.2% with finerenone versus 1.0% with placebo in patients without CVD).

Conclusions:

Among patients with chronic kidney disease and type 2 diabetes, finerenone reduced incidence of the composite cardiovascular outcome, with no evidence of differences in treatment effect based on preexisting CVD status.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02540993.

Arginine and Endothelial Function

Arginine (L-arginine), is an amino acid involved in a number of biological processes, including the biosynthesis of proteins, host immune response, urea cycle, and nitric oxide production. In this systematic review, we focus on the functional role of arginine in the regulation of endothelial function and vascular tone. Both clinical and preclinical studies are examined, analyzing the effects of arginine supplementation in hypertension, ischemic heart disease, aging, peripheral artery disease, and diabetes mellitus.

Albuminuria as a Predictor of Cardiovascular Outcomes in Patients With Acute Myocardial Infarction

Background In patients with myocardial infarction ( MI ), reduced kidney function is recognized as an important predictor of poor prognosis, but the impact of albuminuria, a representative measure of kidney damage, has not been extensively evaluated. Methods and Results In the SCREAM (Stockholm Creatinine Measurements) project (2006-2012), we identified 2469 patients with incident MI with dipstick proteinuria measured within a year before MI (427 patients also had urine albumin to creatinine ratio [ ACR ] measured concurrently) and obtained estimates for ACR with multiple imputation in participants with data solely on dipstick proteinuria. We quantified the association of ACR with the post- MI composite and individual outcomes of all-cause mortality, cardiovascular mortality, recurrent MI , ischemic stroke, or heart failure using Cox models and then evaluated the improvement in C statistic. During a median follow-up of 1.0 year after MI , 1607 participants (65.1%) developed the post- MI composite outcome. Higher ACR levels were independently associated with all outcomes except for ischemic stroke. Per 8-fold higher ACR (eg, 40 versus 5 mg/g), the hazard ratio of composite outcome was 1.21 (95% CI , 1.08-1.35). The addition of the ACR improved the C statistic of the post- MI composite by 0.040 (95% CI, 0.030-0.051). Largely similar results were obtained regardless of diabetic status and when ACR or dipstick was separately analyzed without imputation. Conclusions In patients with MI , albuminuria was a potent predictor of subsequent outcomes, suggesting the importance of paying attention to the information on albuminuria, in addition to kidney function, in this high-risk population.

Sympathetic Overactivity in CKD Disrupts Buffering of Neurotransmission by Endothelium-Derived Hyperpolarizing Factor and Enhances Vasoconstriction

BACKGROUND

Hypertension commonly complicates CKD. Vascular smooth muscle cells (VSMCs) of resistance arteries receive signals from the sympathetic nervous system that induce an endothelial cell (EC)-dependent anticontractile response that moderates vasoconstriction. However, the specific role of this pathway in the enhanced vasoconstriction in CKD is unknown.

METHODS

A mouse model of CKD hypertension generated with 5/6-nephrectomy (5/6Nx) was used to investigate the hypothesis that an impaired anticontractile mechanism enhances sympathetic vasoconstriction. In vivo, ex vivo (isolated mesenteric resistance arteries), and in vitro (VSMC and EC coculture) models demonstrated neurovascular transmission and its contribution to vascular resistance.

RESULTS

By 4 weeks, 5/6Nx mice (versus sham) had augmented increases in mesenteric vascular resistance and mean arterial pressure with carotid artery occlusion, accompanied by decreased connexin 43 (Cx43) expression at myoendothelial junctions (MEJs), impaired gap junction function, decreased EC-dependent hyperpolarization (EDH), and enhanced contractions. Exposure of VSMCs to NE for 24 hours in a vascular cell coculture decreased MEJ Cx43 expression and MEJ gap junction function. These changes preceded vascular structural changes evident only at week 8. Inhibition of central sympathetic outflow or transfection of Cx43 normalized neurovascular transmission and vasoconstriction in 5/6Nx mice.

CONCLUSIONS

5/6Nx mice have enhanced neurovascular transmission and vasoconstriction from an impaired EDH anticontractile component before vascular structural changes. These neurovascular changes depend on an enhanced sympathetic discharge that impairs the expression of Cx43 in gap junctions at MEJs, thereby interrupting EDH responses that normally moderate vascular tone. Dysregulation of neurovascular transmission may contribute to the development of hypertension in CKD.

Comparison of aortic pressures and aortic elastic properties between patients with end-stage renal disease and healthy controls

Background

Current evidence indicates that vascular calcification plays an essential role in the development of cardiovascular diseases in end-stage renal disease (ESRD) patients. Arterial stiffness is a marker of increased cardiovascular risk in various populations. The aim of this study is to evaluate the elastic properties of ascending aorta in patients with ESRD.

Methods

This single-center study enrolled 96 patients (45 females, age: 57.2 ± 12.8 years) with ESRD and 96 healthy controls (52 females, age: 55.3 ± 10.1 years). Aortic pressures and aortic elastic parameters including aortic strain, aortic distensibility, aortic stiffness index, and aortic compliance were calculated using accepted formulae.

Results

The hemodynamic parameters including aortic pulse pressure, aortic mean pressure, aortic fractional pulse pressure, and aortic pulsatility index were significantly higher in patients with ESRD. Systolic and diastolic aortic diameters were similar between the groups. However, pulsatile aortic diameter change, aortic strain, aortic distensibility, and aortic compliance were significantly lower, whereas aortic stiffness index was significantly higher in ESRD group.

Conclusions

The results demonstrated that a significant difference was present in terms of aortic blood pressures between patients with ESRD and controls. In addition, the elastic properties of ascending aorta were decreased in patients with ESRD.

Correlation between kidney and peripheral nerve functions in Type 2 diabetes

BACKGROUND

Although greater impairments in nerve functions parameters are most likely to occur with a lower kidney function, there is a paucity of information on the relationship between the kidney and peripheral nerve functions parameters in Type 2 diabetes.

AIM

To address the impact of peripheral nerve functions in Type 2 diabetes patients in different stages of chronic kidney diseases (CKD).

DESIGN

This prospective study enrolled 238 patients with Type 2 diabetes at a tertiary medical center.

METHOD

We designed composite amplitude scores of nerve conductions (CAS) as a measure of severity of peripheral neuropathy (PN), and used estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (UACR) parameters to stage CKD in Type 2 diabetes patients. The intrapersonal mean, standard deviation and coefficient of variation of eGFR for 238 patients were obtained in the 3 years prior to the study.

RESULTS

The patients who had lower eGFR and higher UACR were older, with longer diabetes duration, a greater percentage of retinopathy and PN and higher CAS. Multiple linear regression analysis revealed that diabetes duration and eGFR were independently associated with CAS, and a cut-off value of eGFR in the presence of PN was 65.3 ml/min/1.73 m2.

CONCLUSION

We observed a close relationship between the severity of kidney and peripheral nerve function in patients with diabetes. If a patient's eGFR value is below 65.3 ml/min/1.73 m2 or the UACR value is above 98.6 mg/dl, caution is needed with the presence of PN even in diabetic patients who are asymptomatic.

Progression of endothelial dysfunction, atherosclerosis, and arterial stiffness in stable kidney transplant patients: a pilot study

Background

Kidney transplant patients suffer from vascular abnormalities and high cardiovascular event rates, despite initial improvements post-transplantation. The nature of the progression of vascular abnormalities in the longer term is unknown. This pilot study investigated changes in vascular abnormalities over time in stable kidney transplant patients long after transplantation.

Methods

Brachial artery flow-mediated dilation (FMD), nitroglycerin-mediated dilation, carotid-femoral pulse wave velocity (cf-PWV), ankle-brachial pressure index, and common carotid artery intima-media thickness (CCA-IMT) were assessed in 18 kidney transplant patients and 17 controls at baseline and 3–6 months after.

Results

There was no difference in age (51 ± 13 vs. 46 ± 11; P = 0.19), body mass index (26 ± 5 vs. 25 ± 3; P = 0.49), serum cholesterol (4.54 ± 0.96 vs. 5.14 ± 1.13; P = 0.10), systolic blood pressure (BP) (132 ± 12 vs. 126 ± 12; P = 0.13), diastolic BP (82 ± 9 vs. 77 ± 8; P = 0.10), or diabetes status (3 vs. 0; P = 0.08) between transplant patients and controls. No difference existed in vascular markers between patients and controls at baseline. In transplant patients, FMD decreased (− 1.52 ± 2.74; P = 0.03), cf-PWV increased (0.62 ± 1.06; P = 0.03), and CCA-IMT increased (0.35 ± 0.53; P = 0.02). No changes were observed in controls.

Conclusion

Markers of vascular structure and function worsen in the post-transplant period on long-term follow-up, which may explain the continued high cardiovascular event rates in this population.

The Influence of Vasoconstritor Use in Local Anesthesia in Individuals with Chronic Renal Failure

AbstractIndividuals with chronic renal failure (CRD) undergo hemodialysis to compensate for systemic-based disease and often develop systemic arterial hypertension (SAH). Such individuals, when needing dental treatment, carry with them the consideration of which type of anesthetic to be used in clinical and surgical interventions. The objective of this study was to evaluate the action of anesthetics with vasoconstrictor (AwV) and without vasoconstrictor (AoV) in individuals with chronic renal failure. Research subjects needed dental treatment, with dental restorations, on the right and left lower dental arch in premolars and / or molars, thus receiving the model of a split-mouth clinical study. In a randomized study, each side of the mandible was subjected to an anesthetic infiltration with only one 1.8 mL tube in two different moments with a minimum interval of 7 days (for one moment with AwV and another AoV moment). The parameters of oxygen saturation (SaO2), heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured 5 minutes before anesthesia, 5, 15 and 30 minutes after anesthesia. The results found in this study showed statistical difference only in SaO2 in the time of 5 minutes after the anesthesia in comparison of the AwV and AoV group, this same result was obtained when only those individuals who, besides nephropathies, had a diagnosis of SAH, were evaluated. The findings of this study highlight the safety of the use of anesthetics, with or without vasoconstrictors since in small amounts, in individuals with CRF with or without associated SAH.Keywords: Renal Insufficiency. Hypertension. Anesthetics, Local.ResumoIndivíduos com insuficiência renal crônica (IRC) em geral são submetidos à hemodiálise para compensação da doença de base sistêmica e frequentemente desenvolvem a hipertensão arterial sistêmica (HAS). Tais indivíduos, ao necessitarem de tratamento odontológico, levam consigo a ponderação de qual tipo de anestésico a ser utilizado em intervenções clínicas e cirúrgicas. O objetivo deste estudo foi avaliar a ação de anestésicos com vasoconstritor (ACV) e sem vasoconstritor (ASV) em indivíduos com insuficiência renal crônica. Os indivíduos da pesquisa tinham necessidade de tratamento odontológico, com restaurações dentárias, no arco dentário inferior direito e esquerdo em pré-molares e/ou molares, recebendo assim o modelo de estudo clínico de boca dividida. De forma aleatória, os hemiarcos inferiores foram submetidos, em dois diferentes momentos com intervalo mínimo de 7 dias, a infiltração anestésica com apenas um tubete de 1,8 mL (para um momento com ACV e outro momento ASV). Foi feita aferição dos parâmetros de saturação de oxigênio (SaO2), frequência cardíaca  (FC), pressão arterial sistólica (PAS) e diastólicas (PAD), 5 minutos antes da anestesia, 5, 15 e 30 minutos após a anestesia. Os resultados encontrados neste estudo demonstraram diferença estatística apenas na SaO2 no tempo de 5 minutos após a anestesia em comparação do grupo ACV e ASV, esse mesmo resultado foi obtido quando avaliados apenas os indivíduos que, além de nefropatas, apresentavam diagnóstico de HAS. Os achados deste estudo ressaltam a segurança do uso de anestésicos, com ou sem vasoconstritores desde que em pequenas quantidades, em indivíduos com IRC com ou sem HAS associada.Palavras-chave: Insuficiência Renal. Hipertensão. Anestésicos Locais.

Endothelial dysfunction and low-grade inflammation in the transition to renal replacement therapy

Introduction

End-stage renal disease (ESRD) strongly associates with cardiovascular disease (CVD) risk. This risk is not completely mitigated by renal replacement therapy. Endothelial dysfunction (ED) and low-grade inflammation (LGI) may contribute to the increased CVD risk. However, data on serum biomarkers of ED and LGI during the transition to renal replacement therapy (dialysis and kidney transplantation) are scarce.

Methods

We compared serum biomarkers of ED and LGI between 36 controls, 43 participants with chronic kidney disease (CKD) stage 5 non-dialysis (CKD5-ND), 20 participants with CKD stage 5 hemodialysis (CKD5-HD) and 14 participants with CKD stage 5 peritoneal dialysis (CKD5-PD). Further, in 34 and 15 participants repeated measurements were available during the first six months following dialysis initiation and kidney transplantation, respectively. Serum biomarkers of ED (sVCAM-1, E-selectin, P-selectin, thrombomodulin, sICAM-1, sICAM-3) and LGI (hs-CRP, SAA, IL-6, IL-8, TNF-α) were measured with a single- or multiplex array detection system based on electro-chemiluminescence technology.

Results

In linear regression analyses adjusted for potential confounders, participants with ESRD had higher levels of most serum biomarkers of ED and LGI than controls. In addition, in CKD5-HD levels of serum biomarkers of ED and LGI were largely similar to those in CKD5-ND. In contrast, in CKD5-PD levels of biomarkers of ED were higher than in CKD5-ND and CKD5-HD. Similarly, in linear mixed model analyses sVCAM-1, thrombomodulin, sICAM-1 and sICAM-3 increased after PD initiation. In contrast, incident HD patients showed an increase in sVCAM-1, P-selectin and TNF-α, but a decline of hs-CRP, SAA and IL-6. Further, following kidney transplantation sVCAM-1, thrombomodulin, sICAM-3 and TNF-α were lower at three months post-transplantation and remained stable in the three months thereafter.

Conclusions

Levels of serum biomarkers of ED and LGI were higher in ESRD as compared with controls. In addition, PD initiation and, less convincingly, HD initiation may increase levels of selected serum biomarkers of ED and LGI on top of uremia per se. In contrast to dialysis, several serum biomarkers of ED and LGI markedly declined following kidney transplantation.

Nephrologists' perspectives on ambulatory care of patients with non-dialysis chronic kidney disease - A qualitative study

Little is known on the perspectives of nephrologists on managing non-dialysis patients with chronic kidney disease (CKD). The purpose of this qualitative study was to explore the experiences and perspectives of nephrologists regarding the interface with general practitioners (GP) and GPs' management of patients with non-dialysis CKD, so that barriers to cooperation and need for improved management can be identified. Twenty semi-structured interviews were conducted for this qualitative study. The interviews were audio-recorded and coded to be analysed. The concept of knowledge systems served as a sensitising concept. Optimising underlying diseases, medication adaptation and patient awareness of CKD were regarded as the most important treatment measures in CKD management. Differing views exist on who should be responsible for lifestyle interventions, patient education and timing of referral. Nephrologists generally preferred the referral of patients with high progression risk and co-treatment models in which daily care was performed by GP, but some preferred referral of all patients with early CKD and some nephrologists stated that patient care should be in the hands of nephrologists entirely in case of CKD. Doctor-patient communication predominantly remained within the medical-scientific knowledge system whereas patients' everyday knowledge systems were rarely considered. While stressing optimisation of laboratory values, diabetes and hypertension, patients' perspectives and shared decision-making to identify and prioritise patients' individual health goals were rarely considered by nephrologists. Instead, most nephrologists regarded educating patients and GPs as an important part of their professional role. Defining the interface between GPs and nephrologists, with specific recommendations on when to refer and which tasks each professional group should perform can lead to standardisation and improved interdisciplinary management of CKD patients. Addressing patients' everyday knowledge systems can be valuable in formulating and prioritising health goals with patients.

Short period of high-intensity inspiratory muscle training improves inspiratory muscle strength in patients with chronic kidney disease on hemodialysis: a randomized controlled trial

BACKGROUND

Chronic kidney disease is a complex disease that impacts multiple organs and systems (including musculoskeletal and cardiorespiratory) leading to reduction of functional capacity.

OBJECTIVE

The aim of this study was to investigate the effect of a short period of high intensity inspiratory muscle training on maximum inspiratory pressure, functional capacity and endothelial function of chronic kidney disease patients on hemodialysis.

METHODS

This randomized controlled trial enrolled 25 patients who were allocated into two groups: intervention (IMTG=14) and control (CG=11) groups. Intervention patients received the exercise protocol over a period of 5 weeks, 6 times per week, with each session consisting of 5 sets of 10 repetitions with an initial load of 50% progressing to 70% of maximum inspiratory pressure , measured weekly. The primary outcome was inspiratory muscle strength and the secondary outcomes were functional capacity and endothelial function evaluated before and after the training protocol.

RESULTS

The inspiratory muscle training induced a marked improvement in maximum inspiratory pressure which was evident after the training period (mean difference 19.0cmH₂O - 95%CI 0.4-37.5; IMTG: 102±25.7cmH₂O vs CG: 83±19.2; p=0.046). The magnitude of maximum inspiratory pressure improvement was 33.5% at the end of the protocol for the IMTG. Functional capacity and endothelial function did not vary between or within groups.

CONCLUSION

A short period of high-intensity inspiratory muscle training for five weeks was able to improve inspiratory muscle strength of chronic kidney disease patients on hemodialysis (ClinicalTrials.gov registration NCT03082404).

Serum Amyloid A Stimulates Vascular and Renal Dysfunction in Apolipoprotein E-Deficient Mice Fed a Normal Chow Diet

Elevated serum amyloid A (SAA) levels may promote endothelial dysfunction, which is linked to cardiovascular and renal pathologies. We investigated the effect of SAA on vascular and renal function in apolipoprotein E-deficient (ApoE^−/−) mice. Male ApoE^−/− mice received vehicle (control), low-level lipopolysaccharide (LPS), or recombinant human SAA by i.p. injection every third day for 2 weeks. Heart, aorta and kidney were harvested between 3 days and 18 weeks after treatment. SAA administration increased vascular cell adhesion molecule (VCAM)-1 expression and circulating monocyte chemotactic protein (MCP)-1 and decreased aortic cyclic guanosine monophosphate (cGMP), consistent with SAA inhibiting nitric oxide bioactivity. In addition, binding of labeled leukocytes to excised aorta increased as monitored using an ex vivo leukocyte adhesion assay. Renal injury was evident 4 weeks after commencement of SAA treatment, manifesting as increased plasma urea, urinary protein, oxidized lipids, urinary kidney injury molecule (KIM)-1 and multiple cytokines and chemokines in kidney tissue, relative to controls. Phosphorylation of nuclear-factor-kappa-beta (NFκB-p-P65), tissue factor (TF), and macrophage recruitment increased in kidneys from ApoE^−/− mice 4 weeks after SAA treatment, confirming that SAA elicited a pro-inflammatory and pro-thrombotic phenotype. These data indicate that SAA impairs endothelial and renal function in ApoE^−/− mice in the absence of a high-fat diet.

PAŞAOĞLU Ö, KESKİN Ç, ARINSOY T, B. DERİCİ Ü. Relationship between plasma YKL-40 levels and endothelial dysfunction in chronic kidney disease

Background/aim

We aimed to evaluate the relationship between YKL-40 and endothelial dysfunction in chronic kidney disease.

Materials and methods

Twenty-nine hemodialysis patients, 101 patients with nondialytic (stage 2, 3, 4, and 5 ND) chronic kidney disease (CKD), and 38 healthy individuals as a control group were included. YKL-40 levels were measured by ELISA. Endothelial dysfunction was indirectly measured by flow-mediated dilatation percentage (FMD) in the brachial artery.

Results

YKL-40 levels were higher in CKD patients than controls and highest in HD patients (P = 0.001). FMD values were lower in nondialytic CKD patients and lowest in HD patients (P = 0.001). YKL-40 negatively correlated with eGFR and FMD values (r = –0.674 and r = –0.471, respectively).

Conclusion

This study shows that YKL-40 increases with CKD stage and is negatively correlated with FMD measurements.

The association between renal function and neurological diseases in type 2 diabetes: a multicenter nationwide cross-sectional study

BACKGROUND

The evidence for an association between renal function and neurological diseases among type 2 diabetes mellitus (T2DM) patients, particularly in the Asian population, is limited. This study aimed to assess the association between glomerular filtration rate (GFR) and various neurological diseases among T2DM patients in Thailand using a nationwide patient sample.

METHODS

We conducted a nationwide cross-sectional study based on the DM/HT study of the Medical Research Network of the Consortium of Thai Medical Schools. This study evaluated adult T2DM patients receiving care at public Thailand hospitals in the year 2014. GFR was categorized into ≥60, 30-59, and < 30 mL/min/1.73 m². Neurological diseases studied included ischemic stroke/transient ischemic attack (TIA), hemorrhagic stroke, dementia, all cerebrovascular disease, and peripheral neuropathy. Multivariate logistic regression was performed to assess the association between GFR and neurological diseases.

RESULTS

A total of 30,423 T2DM patients with available GFR data were included in the analysis. The mean GFR was 68.18 ± 26.45 mL/min/1.73 m². The prevalence of ischemic stroke/TIA, hemorrhagic stroke, dementia, any cerebrovascular diseases and peripheral neuropathy were 2.9%, 0.3%, 0.1%, 3.2%, and 3.1%, respectively. Patients with GFR of 30-59 and <30 mL/min/1.73 m² were significantly associated with increased rates of ischemic stroke/TIA, any cerebrovascular diseases, and peripheral neuropathy when compared with patients with GFR of ≥60 mL/min/1.73 m². This association remained significant after adjustment for potential confounders.

CONCLUSION

Decreased GFR was associated with increased ischemic stroke/TIA, all cerebrovascular diseases, and peripheral neuropathy. GFR should be monitored in diabetic patients for neurological disease awareness and prevention.

Clinical Usefulness of the Cardio-Ankle Vascular Index as a Predictor of Primary Cardiovascular Events in Patients With Chronic Kidney Disease

Background

The cardio-ankle vascular index (CAVI) is a physiologic marker reflecting arterial function. There have been no prospective studies investigating the relationship between CAVI and cardiovascular events in patients with chronic kidney disease (CKD). The aim of this prospective study was to assess the clinical usefulness of CAVI as a predictor of primary cardiovascular events in patients with CKD.

Methods

The study enrolled 460 outpatients with CKD but no history of cardiovascular disease (152 men and 308 women; mean ± standard deviation age, 74 ± 12 years). Patients were assigned to one of three groups: low (L, CAVI < 9; n = 100), medium (M, CAVI 9 - 10; n = 199), or high (H, CAVI > 10; n = 161). The utility of the CAVI as a predictor of primary cardiovascular events was evaluated.

Results

During the follow-up period (median 60.1 months), major adverse cardiovascular events (MACE) occurred in 91 cases (L, 8 (8.0%); M, 31 (15.6%); H, 52 (32.3%); P < 0.001, log-rank test). On multivariate Cox regression analysis, the risk for a MACE was significantly higher in group H than in non-group H (hazard ratio, 2.04; 95% confidence interval, 1.31 - 3.02; P < 0.01). A CAVI cut-off of 9.7 yielded the largest area under the curve, 0.701 (95% confidence interval: 0.657 - 0.743, P < 0.001), indicating a sensitivity of 74.0% and a specificity of 59.6% for discriminating between those who did and did not experience a MACE during follow-up.

Conclusions

The results of this study showed that a high CAVI is a predictor of primary cardiovascular events in patients with CKD.

Vitamin D Attenuates Endothelial Dysfunction in Uremic Rats and Maintains Human Endothelial Stability

Background Dysfunctional endothelium may contribute to the development of cardiovascular complications in chronic kidney disease ( CKD ). Supplementation with active vitamin D has been proposed to have vasoprotective potential in CKD , not only by direct effects on the endothelium but also by an increment of α-Klotho. Here, we explored the capacity of the active vitamin D analogue paricalcitol to protect against uremia-induced endothelial damage and the extent to which this was dependent on increased α-Klotho concentrations. Methods and Results In a combined rat model of CKD with vitamin D deficiency, renal failure induced vascular permeability and endothelial-gap formation in thoracic aorta irrespective of baseline vitamin D, and this was attenuated by paricalcitol. Downregulation of renal and serum α-Klotho was found in the CKD model, which was not restored by paricalcitol. By measuring the real-time changes of the human endothelial barrier function, we found that paricalcitol effectively improved the recovery of endothelial integrity following the addition of the pro-permeability factor thrombin and the induction of a wound. Furthermore, immunofluorescence staining revealed that paricalcitol promoted vascular endothelial-cadherin-based cell-cell junctions and diminished F-actin stress fiber organization, preventing the formation of endothelial intracellular gaps. Conclusions Our results demonstrate that paricalcitol attenuates the CKD -induced endothelial damage in the thoracic aorta and directly mediates endothelial stability in vitro by enforcing cell-cell interactions.

County-level air quality and the prevalence of diagnosed chronic kidney disease in the US Medicare population

BACKGROUND

Considerable geographic variation exists in the prevalence of chronic kidney disease across the United States. While some of this variability can be explained by differences in patient-level risk factors, substantial variability still exists. We hypothesize this may be due to understudied environmental exposures such as air pollution.

METHODS

Using data on 1.1 million persons from the 2010 5% Medicare sample and Environmental Protection Agency air-quality measures, we examined the association between county-level particulate matter ≤2.5 μm (PM2.5) and the prevalence of diagnosed CKD, based on claims. Modified Poisson regression was used to estimate associations (prevalence ratios [PR]) between county PM2.5 concentration and individual-level diagnosis of CKD, adjusting for age, sex, race/ethnicity, hypertension, diabetes, and urban/rural status.

RESULTS

Prevalence of diagnosed CKD ranged from 0% to 60% by county (median = 16%). As a continuous variable, PM2.5 concentration shows adjusted PR of diagnosed CKD = 1.03 (95% CI: 1.02-1.05; p<0.001) for an increase of 4 μg/m3 in PM2.5. Investigation by quartiles shows an elevated prevalence of diagnosed CKD for mean PM2.5 levels ≥14 μg/m3 (highest quartile: PR = 1.05, 95% CI: 1.03-1.07), which is consistent with current ambient air quality standard of 12 μg/m3, but much lower than the level typically considered healthy for sensitive groups (~40 μg/m3).

CONCLUSION

A positive association was observed between county-level PM2.5 concentration and diagnosed CKD. The reliance on CKD diagnostic codes likely identified associations with the most severe CKD cases. These results can be strengthened by exploring laboratory-based diagnosis of CKD, individual measures of exposure to multiple pollutants, and more control of confounding.

Diet-induced hyperhomocysteinemia impairs vasodilation in 5/6-nephrectomized rats

Plasma homocysteine is elevated in patients with impaired renal function, and markedly so at end-stage renal disease. As chronic kidney disease and hyperhomocysteinemia are also independent risk factors for cardiovascular disease, the latter is hypothesized to accelerate vascular abnormalities following renal failure. This study aimed to investigate the combined effect of impaired renal function and hyperhomocysteinemia on vascular function. We show that in 5/6-nephrectomized rats, a model of chronic kidney disease, a methionine-rich diet for 8 weeks induces moderate hyperhomocysteinemia, exacerbates hypertension, and attenuates the vascular response to acetylcholine, sodium nitroprusside, 8-bromo-cGMP, and isoprenaline. However, plasma nitrate/nitrite and total NOS activity in the thoracic aorta were not affected. Collectively, the data imply that hyperhomocysteinemia and end-stage renal disease synergistically impair endothelium-dependent and endothelium-independent vasodilatation by blocking the cGMP/protein kinase G and/or cAMP/protein kinase A pathways. 5/6-Nephrectomized rat with hyperhomocysteinemia induced by a methionine-rich diet would be a useful model for elucidating the pathogenesis of vascular impairment in patients with end-stage renal disease.

Serum Endocan Levels are Associated With Paraoxonase 1 Concentration in Patients With Chronic Kidney Disease

Endocan is a soluble proteoglycan released by the vascular endothelium. The increase of its serum levels is associated with inflammation, endothelial dysfunction and cardiovascular events in patients with chronic kidney disease (CKD). We studied the association of serum endocan with the lipid profile of 105 CKD patients with dyslipidemia, divided in two groups, non-dialyzed (CKD, N = 57) and hemodialysis (HD, N = 48) in comparison with 30 normal controls (NC). We also analyzed endocan in relation with the concentration of two serum HDL-linked members of the paraoxonase (PON) family, PON1 and PON3, which have been previously found to have antiatherogenic properties. The results showed that endocan levels were significantly higher in HD patients than in CKD patients (P < 0.001) and NC (P < 0.001). PON1 was significantly decreased only in HD patients compared to NC (P < 0.001), whereas PON3 was significantly increased in both patient groups (P < 0.001). Endocan levels were significantly and positively correlated with total cholesterol and LDL-C in CKD and additionally were negatively correlated with HDL-C in HD group. PON1 levels were significantly correlated with endocan in both groups, while no correlation was observed for PON3 in either group. Multiple regression analysis between endocan and the above lipid parameters in the total of patients revealed that endocan was independently associated only with PON1 (β = -0.513, P = 0.002). It is concluded that the increase of serum endocan levels in patients with CKD may be associated with the decrease of PON1 concentration, irrespective of lipid alterations produced by atherosclerosis development.

Relationships of kidney injury molecule-1 with renal function and cardiovascular risk factors in the general population

BACKGROUND

Kidney injury molecule-1 (KIM-1) has been associated with kidney damage in patients with preexisting renal disease. However, little is known about the relationships of KIM-1 with renal function and cardiovascular risk factors in healthy individuals from the general population.

METHODS

Healthy individuals aged 25-41years were enrolled in a population-based study. Main exclusion criteria were a BMI >35kg/m², preexisting kidney disease or established cardiovascular disease. KIM-1 was measured from frozen plasma samples using a high-sensitivity assay. Multivariable linear regression models were constructed to assess the relationships of KIM-1 with renal function and various cardiovascular risk factors.

RESULTS

We included 2060 individuals (47% men, median (interquartile range) age: 37 (31-40) years) in this analysis. Median KIM-1 levels were 82.5 (IQR 59.4-112.7) pg/ml. We found no significant relationship of KIM-1 with creatinine (adjusted β-coefficient (95% confidence interval) 0.0005 (-0.002; 0.003), p=0.61) and cystatin C (-0.02 (-0.21; 0.17), p=0.84). There were significant linear relationships of log-transformed KIM-1 with systolic blood pressure (adjusted β-coefficient (95% confidence interval) 0.07 (0.04; 0.09), p<0.0001), diastolic blood pressure (0.04 (0.02; 0.07), p=0.001), low-density lipoprotein cholesterol (0.09 (0.06; 0.11), p<0.0001), high-density lipoprotein cholesterol (0.07 (0.05; 0.1), p<0.0001), high-sensitivity C-reactive protein (0.05 (0.03; 0.07), p<0.0001), age (0.09 (0.07; 0.11), p<0.0001), BMI (0.04 (0.01; 0.06), p=0.005) and current smoking (0.12 (0.07; 0.17), p<0.0001).

CONCLUSION

Among healthy adults from the general population, plasma levels of KIM-1 were not associated with renal function but were independently related to multiple cardiovascular risk factors.

Increased circulating trimethylamine N-oxide contributes to endothelial dysfunction in a rat model of chronic kidney disease

Chronic kidney disease (CKD) is strongly associated with increased cardiovascular risk. Impaired endothelial function, a key initiating step in the pathogenesis of cardiovascular disease, has been reported in patients with CKD, but the mechanisms responsible for endothelial dysfunction in CKD remain elusive. Emerging evidence reveals that trimethylamine-N-oxide (TMAO), a gut microbiota-generated metabolite, is involved in the pathogenesis of many cardiovascular diseases. Circulating TMAO is elevated in CKD. Here we tested the hypothesis that elevated TMAO plays a contributory role in the pathogenesis of endothelial dysfunction in CKD. Rats underwent 5/6 nephrectomy to induce CKD or sham operation, and were treated with 1.0% 3,3-Dimethyl-1-butanol (DMB, an inhibitor of trimethylamine formation) or vehicle. Eight weeks after nephrectomy and DMB treatment, circulating TMAO levels were markedly elevated in CKD-vehicle rats compared with sham-vehicle rats, but were reduced in CKD-DMB rats. Acetylcholine-induced endothelium-dependent vasodilation was impaired in CKD-vehicle rats compared with sham-vehicle rats as indicated by reduced maximal relaxation (E_max) and decreased area under the curve (AUC). E_max and AUC were both normalized in CKD-DMB rats. No difference in sodium nitroprusside-induced endothelial-independent vasodilation was observed across groups. Molecular studies revealed that endothelial nitric-oxide synthase activity was decreased, while superoxide production and proinflammatory cytokine expression were increased in the aorta of CKD-vehicle rats compared with sham-vehicle rats. Of note, the abnormalities in above molecular parameters were completely restored in CKD-DMB rats. These results suggest that CKD elevates circulating TMAO levels, which may reduce eNOS-derived NO production by increasing vascular oxidative stress and inflammation, contributing to CKD-associated endothelial dysfunction and cardiovascular disease.

Role of mitochondria-derived reactive oxygen species in microvascular dysfunction in chronic kidney disease

Cardiovascular disease is the leading cause of mortality in chronic kidney disease (CKD). Mitochondrial dysfunction secondary to CKD is a potential source of oxidative stress that may impair vascular function. This study sought to determine if mitochondria-derived reactive oxygen species contribute to microvascular dysfunction in stage 3-5 CKD. Cutaneous vasodilation in response to local heating was assessed in 20 CKD patients [60 ± 13 yr; estimated glomerular filtration rate (eGFR) 46 ± 13 ml·kg^-1·1.73 m^-2] and 11 matched healthy participants (58 ± 2 yr; eGFR >90 ml·kg^-1·1.73 m^-2). Participants were instrumented with two microdialysis fibers for the delivery of 1) Ringer solution, and 2) the mitochondria- specific superoxide scavenger MitoTempo. Skin blood flow was measured via laser Doppler flowmetry during standardized local heating (42°C). Cutaneous vascular conductance (CVC) was calculated as a percentage of the maximum conductance achieved with sodium nitroprusside infusion at 43°C. Urinary isofuran/F₂-isoprostane ratios were assessed by gas-chromatography mass spectroscopy. Isofuran-to-F₂-isoprostane ratios were increased in CKD patients (3.08 ± 0.32 vs. 1.69 ± 0.12 arbitrary units; P < 0.01) indicative of mitochondria-derived oxidative stress. Cutaneous vasodilation was impaired in CKD compared with healthy controls (87 ± 1 vs. 92 ± 1%CVC_max; P < 0.01). Infusion of MitoTempo significantly increased the plateau phase CVC in CKD patients (CKD Ringer vs. CKD MitoTempo: 87 ± 1 vs. 93 ± 1%CVC_max; P < 0.01) to similar levels observed in healthy controls ( P = 0.9). These data provide in vivo evidence that mitochondria-derived reactive oxygen species contribute to microvascular dysfunction in CKD and suggest that mitochondrial dysfunction may be a potential therapeutic target to improve CKD-related vascular dysfunction.

Inflammation and Arterial Stiffness in Chronic Kidney Disease: Findings From the CRIC Study

BACKGROUND

Chronic kidney disease (CKD) and arterial stiffness are associated with increased cardiovascular morbidity and mortality. Inflammation is proposed to have a role in the development of arterial stiffness, and CKD is recognized as a proinflammatory state. Arterial stiffness is increased in CKD, and cross-sectional data has suggested a link between increased inflammatory markers in CKD and higher measures of arterial stiffness. However, no large scale investigations have examined the impact of inflammation on the progression of arterial stiffness in CKD.

METHODS

We performed baseline assessments of 5 inflammatory markers in 3,939 participants from the chronic renal insufficiency cohort (CRIC), along with serial measurements of arterial stiffness at 0, 2, and 4 years of follow-up.

RESULTS

A total of 2,933 participants completed each of the follow-up stiffness measures. In cross-sectional analysis at enrollment, significant associations with at least 2 measures of stiffness were observed for fibrinogen, interleukin-6, high-sensitivity C-reactive protein, proteinuria, and composite inflammation score after adjustment for confounders. In longitudinal analyses, there were few meaningful correlations between baseline levels of inflammation and changes in metrics of arterial stiffness over time.

CONCLUSION

In a large cohort of CKD participants, we observed multiple significant correlations between initial markers of inflammation and metrics of arterial stiffness, but baseline inflammation did not predict changes in arterial stiffness over time. While well-described biologic mechanisms provide the basis for our understanding of the cross-sectional results, continued efforts to design longitudinal studies are necessary to fully elucidate the relationship between chronic inflammation and arterial stiffening.

Is chronic kidney disease-mineral and bone disorder associated with the presence of endothelial progenitor cells with a calcifying phenotype?

Background: Chronic kidney disease-mineral and bone disorder (CKD-MBD) has been implicated in vascular calcification pathogenesis. CKD-MBD results in alterations in the number and function of circulating endothelial progenitor cells (EPCs), physiological regulators of angiogenesis and vessel repair, commonly defined as proangiogenic progenitor cells (PACs) by the antigen pattern CD34+CD133+KDR+CD45– and putative EPCs by the pattern CD34+CD133−KDR+CD45–. These cells might acquire a calcifying phenotype in CKD-MBD, expressing mineralization biomarkers. We investigated the expression of vitamin D receptor (VDR) and osteocalcin (OC) on EPCs of healthy individuals and haemodialysis patients, and their possible associations with circulating biomarkers of inflammation and vascular calcification.

Methods: We compared EPC counts, expressing VDR or OC, in 23 healthy subjects versus 53 haemodialysis patients, 17 of them without vitamin D receptor agonist (VDRA) therapy and 35 treated with calcitriol (n  =  17) or paricalcitol (n  =  18). The correlations with serum levels of inflammatory and calcification indexes were also analysed.

Results: All subsets expressing VDR or OC were significantly higher in haemodialysis patients compared with healthy controls, but PACs were increased only in VDRA treatment subgroup, while putative EPCs showed a similar rise also in untreated patients. In VDRA-untreated patients, OC+  PACs correlated positively with calcium levels, while in VDRA-treated patients, VDR+ PACs correlated positively with interleukin 6 levels, and OC+  PACs correlated positively 25-hydroxyvitamin D levels.

Conclusions: Our data suggest that in CKD-MBD, EPCs undergo an endothelial-to-procalcific shift, representing a risk factor for vascular calcification. A link between mineral disorders and vitamin D replacement therapy emerged, with potential adverse effects for CKD patients.

Cardiovascular impact in patients undergoing maintenance hemodialysis: Clinical management considerations

Patients undergoing maintenance hemodialysis develop both structural and functional cardiovascular abnormalities. Despite improvement of dialysis technology, cardiovascular mortality of this population remains high. The pathophysiological mechanisms of these changes are complex and not well understood. It has been postulated that several non-traditional, uremic-related risk factors, especially the long-term uremic state, which may affect the cardiovascular system. There are many cardiovascular changes that occur in chronic kidney disease including left ventricular hypertrophy, myocardial fibrosis, microvascular disease, accelerated atherosclerosis and arteriosclerosis. These structural and functional changes in patients receiving chronic dialysis make them more susceptible to myocardial ischemia. Hemodialysis itself may adversely affect the cardiovascular system due to non-physiologic fluid removal, leading to hemodynamic instability and initiation of systemic inflammation. In the past decade there has been growing awareness that pathophysiological mechanisms cause cardiovascular dysfunction in patients on chronic dialysis, and there are now pharmacological and non-pharmacological therapies that may improve the poor quality of life and high mortality rate that these patients experience.

Endothelial Function Assessed by Automatic Measurement of Enclosed Zone Flow-Mediated Vasodilation Using an Oscillometric Method Is an Independent Predictor of Cardiovascular Events

BACKGROUND

A new device for automatic measurement of flow-mediated vasodilation (FMD) using an oscillometric method has been developed to solve technical problems of conventional FMD measurement. This device measures enclosed zone FMD (ezFMD). The purpose of this study was to evaluate the prognostic value of endothelial function assessed by ezFMD for future cardiovascular events.

METHODS AND RESULTS

We measured ezFMD in 272 participants who underwent health-screening examinations. First, we investigated cross-sectional associations between ezFMD and cardiovascular risk factors, and then we assessed the associations between ezFMD and first major cardiovascular events (death from cardiovascular causes, stroke, and coronary revascularization). Univariate regression analysis revealed that ezFMD was significantly correlated with age, triglycerides, glucose, smoking pack-years, estimated glomerular filtration rate, high-sensitivity C-reactive protein, and Framingham risk score. During a median follow-up period of 36.1 months (interquartile range 18.8-40.1 months), 12 participants died (6 from cardiovascular causes), 3 had stroke, 8 had coronary revascularization, and 10 were hospitalized for heart failure. There was no episode of acute coronary syndrome during the study period. Participants were divided into tertiles (low, intermediate, and high) based on ezFMD. Kaplan-Meier curves for first major cardiovascular events among the 3 groups were significantly different (P=0.004). After adjustment for cardiovascular risk factors, the low group was significantly associated with an increased risk of first major cardiovascular events compared with the high group (hazard ratio 6.47; 95% CI 1.09-125.55; P=0.038).

CONCLUSIONS

These findings suggest that endothelial function assessed by ezFMD may be useful as a surrogate marker of future cardiovascular events.

CLINICAL TRIAL REGISTRATION

URL: https://upload.umin.ac.jp. Unique identifier: UMIN000004902.

Serum Osteoprotegerin Levels Related With Cardiovascular Risk Factors in Chronic Kidney Disease

BACKGROUND

To evaluate osteoprotegerin (OPG) levels in relation to cardiovascular (CV) risk factors in patients with chronic kidney disease (CKD) on different regimens of renal replacement therapy.

METHODS

A total of 143 patients with CKD and 30 healthy controls were included in this study and divided into five categories, including predialysis patients with chronic renal failure (preD; n = 36), chronic peritoneal dialysis patients (PD; n = 36), hemodialysis patients (HD; n = 35), renal transplant patients (RT; n = 36), and controls (n = 30). Data on demographics, concomitant diseases and CV risk factors, serum OPG levels, and correlates of serum OPG levels were determined.

RESULTS

Serum OPG (pmol/l) levels were significantly higher in HD (P <0.001 for each), PD (P <0.001 for each), and preD (P <0.01 vs. control, P <0.05 vs. RT) groups than RT and control groups. Diabetics than nondiabetics in HD (P = 0.008), PD (P = 0.024), and RT (P = 0.004) groups and males than females in PD group (P = 0.021) had higher OPG levels. Serum OPG levels were associated positively with age in HD (P <0.001), PD (P = 0.001), and in overall population (P <0.001).

CONCLUSION

Our findings revealed increased serum levels of OPG in dialysis and preD patients compared to RT and controls. In the patient groups receiving two dialysis treatment, the levels were worse, indicating a more pronounced vascular injury. Age, C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C), and cystatin C (CysC) in CKD patients, CRP and PTH in the control subjects, and age and BMI in the overall population were the significant correlates of serum OPG levels.

Albuminuria and cardiovascular events in patients with acute coronary syndromes: Results from the TRACER trial

BACKGROUND

Albuminuria is associated with cardiovascular (CV) outcomes. We evaluated albuminuria, alone and in combination with estimated glomerular filtration rate (eGFR), as a predictor of mortality and CV morbidity in 12,944 patients with non-ST-segment elevation acute coronary syndromes.

METHODS

Baseline serum creatinine and urinary dipsticks were obtained, with albuminuria stratified into no/trace albuminuria, microalbuminuria (≥30 but <300 mg/dL), or macroalbuminuria (≥300 mg/dL). Kaplan-Meier rates and proportional Cox hazards models of CV death, overall mortality, CV death or myocardial infarction (MI), and bleeding were calculated. Incidence of acute kidney injury, identified by adverse event reporting and creatinine increase (absolute ≥0.3 mg/dL or relative ≥50%), was descriptively reported.

RESULTS

Both dipstick albuminuria and creatinine values were available in 9473 patients (73.2%). More patients with macroalbuminuria, versus no/trace albuminuria, had diabetes (66% vs 27%) or hypertension (86% vs 68%). Rates for CV death and overall mortality per strata were 3.1% and 4.8% (no/trace albuminuria); 5.8% and 9.0% (microalbuminuria); and 7.7% and 12.6% (macroalbuminuria) at 2 years of follow-up. Corresponding rates for CV death or MI were 12.2%, 16.9%, and 23.5%, respectively. Observed acute kidney injury rates were 0.6%, 1.2%, and 2.9% (n = 79), respectively. Adjusted HRs for macroalbuminuria on CV mortality were 1.65 (95% CI 1.15-2.37), and after adjustment with eGFR, 1.37 (95% CI 0.93-2.01). Corresponding HRs for overall mortality were 1.82 (95% CI 1.37-2.42) and 1.47 (95% CI 1.08-1.98).

CONCLUSIONS

High-risk patients with non-ST-segment elevation acute coronary syndromes and albuminuria have increased morbidity and increased overall mortality independent of eGFR.

Subfractions of high-density lipoprotein (HDL) and dysfunctional HDL in chronic kidney disease patients

A number of studies have shown that chronic kidney disease (CKD) is associated with increased risk for cardiovascular disease (CVD). Chronic kidney disease is characterized by significant disturbances in lipoprotein metabolism, including differences in quantitative and qualitative content of high-density lipoprotein (HDL) particles. Recent studies have revealed that serum HDL cholesterol levels do not predict CVD in CKD patients; thus CKD-induced modifications in high-density lipoprotein (HDL) may be responsible for the increase in CV risk in CKD patients. Various methods are available to separate several subclasses of HDL and confirm their atheroprotective properties. However, under pathological conditions associated with inflammation and oxidation, HDL can progressively lose normal biological activities and be converted into dysfunctional HDL. In this review, we highlight the current state of knowledge on subfractions of HDL and HDL dysfunction in CKD.