Traditional and non-traditional risk factors for incident peripheral arterial disease among patients with chronic kidney disease

FGF23 as a Potential Pathophysiological Factor in Peripheral Arterial Disease Associated with Chronic Kidney Disease

Fibroblast growth factor 23 (FGF23) levels are often elevated in chronic kidney disease (CKD). FGF23 and inflammation are common characteristics in CKD, and both are associated with worse disease progression and the occurrence of complications. The existence of an interaction between FGF23 and inflammation has been suggested, each of which influences the expression and activity of the other, leading to a vicious feedback loop with adverse outcomes, including cardiovascular disease and mortality. In this work, we determined circulating FGF23 levels in a group of patients with CKD stages 3 and 4 subjected to elective femoral endarterectomy due to established peripheral artery disease (PAD), a condition resulting from an athero-inflammatory process, and we studied its associations with different inflammatory markers and mediators. We evaluated its association with serum tumor necrosis factor (TNF)α, interleukin (IL) 6, and IL10, as well as with the gene expression levels of these parameters and A disintegrin and metalloproteinase domain-containing protein (ADAM) 17 in femoral vascular tissue and peripheral blood circulating cells (PBCCs). We also analyzed its association with serum concentrations of C-reactive protein (CRP), the systemic immune inflammation index (SII), and the neutrophil-to-lymphocyte ratio (NLR). Finally, we determined the vascular immunoreactivity of protein TNFα in a subgroup of patients. FGF23 concentrations were independently associated with circulating and PBCC mRNA levels of TNFα. Worst kidney function and diabetes were also found to be contributing to FGF23 levels. Patients with higher levels of FGF23 also had greater vascular immunoreactivity for TNFα.

Prevalence, clinical profile, and risk factors of peripheral artery disease in an Iraqi cohort of chronic kidney disease

Peripheral artery disease (PAD) is prevalent in patients with chronic kidney disease (CKD) and is associated with substantial morbidity, mortality, and a lower quality of life. This study aimed to determine the prevalence of PAD, clinical profile, and related risk factors among patients with CKD in Iraq (a low-to middle-income country). A cross sectional study comprised 175 CKD patients, of them 60% were male, their mean age was 56 ± 12.5 years, attending Nephrology unit, Hawler Teaching Hospital, Erbil, Iraq between march 2022 and November 2022. Data on demographic and baseline characteristics were collected. Laboratory tests were performed. All participants underwent a detailed history and clinical examination. Vascular lesions in the lower limbs were assessed using the ankle-brachial index. PAD was diagnosed based on an ankle-brachial index value ˂ 0.9, relevant symptoms, and clinical findings. Forty-nine patients (28%) had PAD, and only 17 (34.7%) were symptomatic. PAD was significantly associated with older age (P = .008), male sex (P = .039), diabetes (P = .012), and hypertension (P = .023). In addition, PAD prevalence was significantly higher in patients with prior coronary artery disease (P < .001), advanced CKD stages (P .032), low estimated glomerular filtration rate (P .03), albuminuria (P .002), elevated glycated hemoglobin (P .04), and high sensitive C-reactive protein (P < .001). No significant association was detected between PAD and body mass index, smoking, CKD duration, cerebrovascular disease, dyslipidemia, albumin, creatinine, hemoglobin, total PTH, and phosphate. Peripheral artery disease was prevalent in patients with CKD in Iraq, and the most affected patients were asymptomatic. Older age, male sex, hypertension, diabetes, prior coronary artery disease, advanced CKD stages, albuminuria, higher glycated hemoglobin level, and increased high-sensitivity C-reactive protein level were identified as risk factors. Early detection of occult PAD might enhance efforts toward proper prevention and treatment.

The Effect of PCSK9 Inhibition on the Stabilization of Atherosclerotic Plaque Determined by Biochemical and Diagnostic Imaging Methods

Atherosclerosis is a multifactorial, progressive, chronic inflammatory disease. Ultrasound and magnetic resonance imaging are the most accurate predictors of atherosclerotic plaque instability (MRI). Cytokines such as osteopontin, osteoprotegerin, and metalloproteinase 9 could be used as the most recent markers to identify and track the efficacy of anti-atherosclerotic therapy. Patients with USG and MRI-verified unstable atherosclerotic plaque were included in the study. Biomarker concentrations were measured and compared before and after PCSK9 inhibitor therapy. Additionally, concentrations prior to treatment were correlated with MRI images of the carotid artery. After treatment with alirocumab, the concentrations of MMP-9 (p < 0.01) and OPN, OPG (p < 0.05) decreased significantly. Furthermore, the results of OPN, OPG, and MMP 9 varied significantly depending on the type of atherosclerotic plaque in the MRI assay. In stable atherosclerotic plaques, the concentrations of OPN and OPG were greater (p < 0.01), whereas the concentration of MMP9 correlated with the instability of the plaque (p < 0.05). We demonstrated, probably for the first time, that alirocumab therapy significantly decreased the serum concentration of atherosclerotic plaque markers. In addition, we demonstrated the relationship between the type of atherosclerotic plaque as determined by carotid MRI and the concentration of these markers.

ADAM10 and ADAM17, Major Regulators of Chronic Kidney Disease Induced Atherosclerosis?

Chronic kidney disease (CKD) is a major health problem, affecting millions of people worldwide, in particular hypertensive and diabetic patients. CKD patients suffer from significantly increased cardiovascular disease (CVD) morbidity and mortality, mainly due to accelerated atherosclerosis development. Indeed, CKD not only affects the kidneys, in which injury and maladaptive repair processes lead to local inflammation and fibrosis, but also causes systemic inflammation and altered mineral bone metabolism leading to vascular dysfunction, calcification, and thus, accelerated atherosclerosis. Although CKD and CVD individually have been extensively studied, relatively little research has studied the link between both diseases. This narrative review focuses on the role of a disintegrin and metalloproteases (ADAM) 10 and ADAM17 in CKD and CVD and will for the first time shed light on their role in CKD-induced CVD. By cleaving cell surface molecules, these enzymes regulate not only cellular sensitivity to their micro-environment (in case of receptor cleavage), but also release soluble ectodomains that can exert agonistic or antagonistic functions, both locally and systemically. Although the cell-specific roles of ADAM10 and ADAM17 in CVD, and to a lesser extent in CKD, have been explored, their impact on CKD-induced CVD is likely, yet remains to be elucidated.

The Role of Neutrophils in Lower Limb Peripheral Artery Disease: State of the Art and Future Perspectives

In recent years, increasing attention has been paid to the role of neutrophils in cardiovascular (CV) disease (CVD) with evidence supporting their role in the initiation, progression, and rupture of atherosclerotic plaque. Although these cells have long been considered as terminally differentiated cells with a relatively limited spectrum of action, recent research has revealed intriguing novel cellular functions, including neutrophil extracellular trap (NET) generation and inflammasome activation, which have been linked to several human diseases, including CVD. While most research to date has focused on the role of neutrophils in coronary artery and cerebrovascular diseases, much less information is available on lower limb peripheral artery disease (PAD). PAD is a widespread condition associated with great morbidity and mortality, though physician and patient awareness of the disease remains low. To date, several studies have produced some evidence on the role of certain biomarkers of neutrophil activation in this clinical setting. However, the etiopathogenetic role of neutrophils, and in particular of some of the newly discovered mechanisms, has yet to be fully elucidated. In the future, complementary assessment of neutrophil activity should improve CV risk stratification and provide personalized treatments to patients with PAD. This review aims to summarize the basic principles and recent advances in the understanding of neutrophil biology, current knowledge about the role of neutrophils in atherosclerosis, as well as available evidence on their role of PAD.

Toll-like receptors 2 and 4 stress signaling and sodium-glucose cotransporter-2 in kidney disease

Kidney disease is the 6th fastest-growing cause of death and a serious global health concern that urges effective therapeutic options. The inflammatory response is an initial reaction from immune and parenchymal cells in kidney diseases. Toll-like receptors (TLR) 2 and 4 are highly expressed by various kidney cells and respond to 'signaling danger' proteins, such as high mobility group box binding protein 1 (HMGB1) and prompt the progression of kidney disease by releasing inflammatory mediators. Burgeoning reports suggest that both SGLT2 and ER stress elevates TLR2/4 signaling via different axis. Moreover, SGLT2 signaling aggravates inflammation under the disease condition by promoting the NLR family pyrin domain-containing three inflammasomes and ER stress. Intriguingly, TLR2/4 downstream adaptors activate ER stress regulators. The above-discussed interactions imply that TLR2/4 does more than immune response during kidney disease. Here, we discuss in detail evidence of the roles and regulation of TLR2/4 in the context of a relationship between ER stress and SGLT2. Also, we highlighted different preclinical studies of SGLT2 inhibitors against TLR2/4 signaling in various kidney diseases. Moreover, we discuss the observational and interventional evidence about the relation between TLR2/4, ER stress, and SGLT2, which may represent the TLR2/4 as a potential therapeutic target for kidney disease.

Clinical utility of bone turnover markers in patients with chronic kidney disease

PURPOSE OF REVIEW

The burden of fractures is very high in patients with chronic kidney disease (CKD). It is increasingly recognized that knowledge of bone turnover is of paramount importance in guiding mineral metabolism and osteoporosis therapy in CKD. Bone histomorphometry is the gold standard to assess bone turnover, but is seldomly performed in clinical practice. Bone turnover markers (BTMs) may be the long awaited noninvasive diagnostic that may help to close the therapeutic gap in patients with advanced CKD presenting with bone fragility.

RECENT FINDINGS

Mounting evidence indicates that BTMs may be useful in skeletal and nonskeletal risk stratification, in guiding mineral metabolism and osteoporosis therapy, and in monitoring the therapeutic response.

SUMMARY

BTMs provide information that is complementary to other clinical tests. It may be envisioned that in the near future, the assessment of nonkidney cleared BTMs may become part of routine clinical evaluation and monitoring of bone health in CKD patients, integrated with clinical risk factors, imaging data and, eventually, bone histomorphometry. Panels of BTMs will likely be more informative than single markers, and the same might hold true for trends as opposed to single time point data.

Uremic Toxins and Cardiovascular Risk in Chronic Kidney Disease: What Have We Learned Recently beyond the Past Findings?

Patients with chronic kidney disease (CKD) have an elevated prevalence of atheromatous (ATH) and/or non-atheromatous (non-ATH) cardiovascular disease (CVD) due to an array of CKD-related risk factors, such as uremic toxins (UTs). Indeed, UTs have a major role in the emergence of a spectrum of CVDs, which constitute the leading cause of death in patients with end-stage renal disease. The European Uremic Toxin Work Group has identified over 100 UTs, more than 25 of which are dietary or gut-derived. Even though relationships between UTs and CVDs have been described in the literature, there are few reviews on the involvement of the most toxic compounds and the corresponding physiopathologic mechanisms. Here, we review the scientific literature on the dietary and gut-derived UTs with the greatest toxicity in vitro and in vivo. A better understanding of these toxins’ roles in the elevated prevalence of CVDs among CKD patients might facilitate the development of targeted treatments. Hence, we review (i) ATH and non-ATH CVDs and the respective levels of risk in patients with CKD and (ii) the mechanisms that underlie the influence of dietary and gut-derived UTs on CVDs.

Determinants and Outcomes Associated With Urinary Calcium Excretion in Chronic Kidney Disease

CONTEXT

Abnormalities in calcium metabolism are common in chronic kidney disease (CKD). Diminished urinary calcium excretion may promote vascular calcification and increased urinary calcium excretion may lead to nephrolithiasis and nephrocalcinosis, conditions associated with CKD.

OBJECTIVE

To study predictors of urinary calcium excretion and its association with adverse clinical outcomes in CKD.

DESIGN, SETTING AND PATIENTS

This study assessed 3768 nondialysis participants in the Chronic Renal Insufficiency Cohort study from April 2003 to September 2008. Participants were followed up to October 2018.

EXPOSURE

Clinically plausible predictors of urinary calcium excretion and 24-h urinary calcium excretion at baseline.

MAIN OUTCOME MEASURES

Urinary calcium excretion; incident end stage kidney disease (ESKD), CKD progression [50% estimated glomerular filtration rate (eGFR) decline or incident ESKD], all-cause mortality, and atherosclerotic cardiovascular disease events.

RESULTS

eGFR was positive correlated with 24-h urinary calcium excretion. The variables most strongly associated with 24-h urinary calcium excretion in males and females were 24-h urinary sodium (β = 0.19 and 0.28, respectively), serum parathyroid hormone (β = -0.22 and -0.20, respectively), loop diuretics (β = 0.36 and 0.26, respectively), thiazide diuretics (β = -0.49 and -0.53, respectively), and self-identified black race (β = -0.23 and -0.27, respectively). Lower urinary calcium excretion was associated with greater risks of adverse outcomes, but these associations were greatly attenuated or nullified after adjustment for baseline eGFR.

CONCLUSION

Urinary calcium excretion is markedly lower in individuals with CKD compared to the general population. Determinants of urinary calcium excretion differed between sexes and levels of CKD. Associations between urinary calcium excretion and adverse clinical events were substantially confounded by eGFR.

Myeloperoxidase is Independently Associated with Incident Heart Failure in Patients with Coronary Artery Disease and Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is associated with high cardiovascular risk and mortality. Myeloperoxidase (MPO) has been linked to adverse events in patients with mild-moderate CKD. We sought to investigate whether MPO levels are associated with adverse outcomes in patients with CKD METHODS: We studied participants with mild to moderate CKD in the prospective chronic renal insufficiency cohort (CRIC). We followed patients for incident heart failure (HF), death, and composite outcome (myocardial infarction, incident peripheral arterial disease, cerebrovascular accident and death). .

RESULTS

A total of 3872 patients were included (2702 without CVD, 1170 with CVD). After multiple adjustments, doubling of MPO in patients with prior CAD was associated with risk of HF (HR 1.15 [1.01-1.30], P=0.032) and mortality (HR 1.16 [1.05-1.30], P=0.005), and composite outcome of MI, PAD, CVA and death (HR 1.12 [1.01-1.25], p=0.031).

CONCLUSIONS

In this cohort of patients with mild to moderate CKD and CAD, MPO levels are independently associated with incident HF, all-cause mortality, and a composite outcome.

Association of plasma neutrophil gelatinase-associated lipocalin with parameters of CKD-MBD in maintenance hemodialysis patients

INTRODUCTION

Neutrophil gelatinase-associated lipocalin (NGAL) is not only a biomarker of kidney injury but also a bone-derived factor involved in metabolism. We aimed to explore relationships between plasma NGAL and chronic kidney disease-mineral bone disorder (CKD-MBD) parameters in maintenance hemodialysis (MHD) patients.

MATERIALS AND METHODS

First, a cross sectional observational study, including 105 MHD patients, was conducted to explore relationships between plasma NGAL levels and CKD-MBD parameters. Second, impact of parathyroidectomy and auto-transplantation (PTX + AT) on plasma NGAL was investigated in 12 MHD patients with severe secondary hyperparathyroidism (SHPT).

RESULTS

According to Spearman correlation analysis, plasma NGAL levels were positively correlated with female (r = 0.243, P = 0.012), vintage (r = 0.290, P = 0.003), Klotho (r = 0.234, P = 0.016), calcium(Ca) (r = 0.332, P = 0.001), alkaline phosphatase (ALP) (r = 0.401, P < 0.001) and intact parathyroid hormone (iPTH) (r = 0.256, P = 0.008); while inversely correlated with albumin(Alb) (r = - 0.201, P = 0.039). After adjusting for age, sex, vintage, Alb and all parameters of CKD-MBD(Ca, P, lg(ALP), lg(iPTH), Klotho and fibroblast growth factor 23(FGF23)), lg(NGAL) were positively correlated with Ca (r = 0.481, P < 0.001), P (r = 0.336, P = 0.037), lg(ALP) (r = 0.646, P < 0.001) in Partial correlation analysis; further multiple linear regression analysis showed same positive associations between lg(NGAL) and Ca (β = 0.330, P = 0.002), P (β = 0.218, P = 0.037), lg(ALP) (β = 0.671, P < 0.001). During the 4-7 days after PTX + AT, plasma NGAL decreased from 715.84 (578.73, 988.14) to 688.42 (660.00, 760.26) ng/mL (P = 0.071), Klotho increased from 496.45 (341.73, 848.30) to 1138.25 (593.87, 2009.27) pg/mL (P = 0.099).

CONCLUSION

Plasma NGAL levels were positively associated with ALP in MHD patients; and downtrends were shown after PTX + AT in patients with severe SHPT. These findings suggest that NGAL is a participant in CKD-MBD under MHD condition.

Pilot study to investigate differences in middle molecules, oxidative stress and markers of peripheral vascular disease in patients treated by high flux haemodialysis and haemodiafiltration

Background

Dialysis patients have an increased risk of mortality. Recently treatment with haemodiafiltration (HDF) has been reported to reduce mortality, particularly cardiovascular mortality, compared to standard high-flux haemodialysis (HD). However, why HDF may offer a survival advantage remains to be determined. So, we conducted a pilot study to explore differences in middle-molecules, inflammation and markers of vascular disease in patients treated by HD and HDF.

Methods

Observational cross-sectional study measuring serum β2-microglobulin (β2M), Advanced Glycosylation End Products (AGEs) by skin autofluorescence (SAF), oxidative stress with ischaemia modified albumin ratio (IMAR) and peripheral vascular disease assessment using Ankle-Brachial Index (ABI), and arterial stiffness using Cardio-Ankle Vascular Index (CAVI).

Results

We studied 196 patients, mean age 69.1 ± 12.4 years, 172 (87.8%) treated by HD and 24 (12.2%) by HDF. Age, body mass index, co-morbidity and dialysis vintage were not different between HD and HDF groups. Middle molecules; β₂M (31±9.9 vs 31.2±10 ug/mL) and SAF (2.99±0.72 vs 3.0±0.84 AU), ABI (1.06±0.05 vs 1.07±0.10) and CAVI (9.34±1.55 vs 9.35±1.23) were not different, but IMAR was higher in the HD patients (38.4±14.8 vs 31.3 ± 17.4, P = 0.035)

Conclusions

In this pilot observational study, we found patients treated by HDF had lower oxidative stress as measured by IMAR, with no differences in middle molecules. Lower oxidative stress would be expected to have diverse protective effects on the cardiovascular system Although we found no differences in ABI and CAVI, future studies are required to determine whether reduced oxidative stress translates into clinically relevant differences over time.

Peripheral Vascular Disease and Kidney Transplant Outcomes: Rethinking an Important Ongoing Complication

Peripheral vascular disease (PVD) is highly prevalent in patients on the waiting list for kidney transplantation (KT) and after transplantation and is associated with impaired transplant outcomes. Multiple traditional and nontraditional risk factors, as well as uremia- and transplant-related factors, affect 2 processes that can coexist, atherosclerosis and arteriosclerosis, leading to PVD. Some pathogenic mechanisms, such as inflammation-related endothelial dysfunction, mineral metabolism disorders, lipid alterations, or diabetic status, may contribute to the development and progression of PVD. Early detection of PVD before and after KT, better understanding of the mechanisms of vascular damage, and application of suitable therapeutic approaches could all minimize the impact of PVD on transplant outcomes. This review focuses on the following issues: (1) definition, epidemiological data, diagnosis, risk factors, and pathogenic mechanisms in KT candidates and recipients; (2) adverse clinical consequences and outcomes; and (3) classical and new therapeutic approaches.

Applying Proteomics and Integrative "Omics" Strategies to Decipher the Chronic Kidney Disease-Related Atherosclerosis

Patients with chronic kidney disease (CKD) are at increased risk of atherosclerosis and premature mortality, mainly due to cardiovascular events. However, well-known risk factors, which promote “classical” atherosclerosis are alone insufficient to explain the high prevalence of atherosclerosis-related to CKD (CKD-A). The complexity of the molecular mechanisms underlying the acceleration of CKD-A is still to be defied. To obtain a holistic picture of these changes, comprehensive proteomic approaches have been developed including global protein profiling followed by functional bioinformatics analyses of dysregulated pathways. Furthermore, proteomics surveys in combination with other “omics” techniques, i.e., transcriptomics and metabolomics as well as physiological assays provide a solid ground for interpretation of observed phenomena in the context of disease pathology. This review discusses the comprehensive application of various “omics” approaches, with emphasis on proteomics, to tackle the molecular mechanisms underlying CKD-A progression. We summarize here the recent findings derived from global proteomic approaches and underline the potential of utilizing integrative systems biology, to gain a deeper insight into the pathogenesis of CKD-A and other disorders.

Management of diabetes mellitus in dialysis patients: Obstacles and challenges

BACKGROUND AND AIMS

Diabetic kidney disease (DKD) is a major health issue that is associated with an increased risk of morbidity and mortality. The treatment of DKD is challenging given changes in blood glucose homeostasis, unclear accuracy of glucose metrics, and altered kinetics of the blood glucose-lowering medications. There is uncertainty surrounding the optimal glycemic target in this population although recent epidemiologic data suggest that HbA1c ranges of 6-8%, as well as 7-9%, are associated with increased survival rates among diabetic dialysis patients. Furthermore, the treatment of diabetes in patients maintained on dialysis is challenging, and many blood glucose-lowering medications are renally metabolized and excreted hence requiring dose adjustment or avoidance in dialysis patients.

METHOD

ology: PubMed, Google Scholar, and Medline were searched for all literature discussing the management of diabetes in dialysis patients.

RESULTS

The literature was discussed under many subheadings providing the latest evidence in the treatment of diabetes in dialysis patients.

CONCLUSION

The management of diabetes in dialysis is very complex requiring a multi-disciplinary team involving endocrinologists and nephrologists to achieve targets and reduce morbidity and mortality.

Targeting Uremic Toxins to Prevent Peripheral Vascular Complications in Chronic Kidney Disease

Chronic kidney disease (CKD) exhibits progressive kidney dysfunction and leads to disturbed homeostasis, including accumulation of uremic toxins, activated renin-angiotensin system, and increased oxidative stress and proinflammatory cytokines. Patients with CKD are prone to developing the peripheral vascular disease (PVD), leading to poorer outcomes than those without CKD. Cumulative evidence has showed that the synergy of uremic milieu and PVD could exaggerate vascular complications such as limb ischemia, amputation, stenosis, or thrombosis of a dialysis vascular access, and increase mortality risk. The role of uremic toxins in the pathogenesis of vascular dysfunction in CKD has been investigated. Moreover, growing evidence has shown the promising role of uremic toxins as a therapeutic target for PVD in CKD. This review focused on uremic toxins in the pathophysiology, in vitro and animal models, and current novel clinical approaches in reducing the uremic toxin to prevent peripheral vascular complications in CKD patients.

Association between nontraditional lipid profiles and peripheral arterial disease in Chinese adults with hypertension

BACKGROUND

Data on the relationship between nontraditional lipid profiles [total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio, triglyceride (TG)/HDL-C ratio, low-density lipoprotein cholesterol (LDL-C)/HDL-C ratio, non-high-density lipoprotein cholesterol (non-HDL-C)] and the risk of peripheral artery disease (PAD) are limited. The present study investigated the relationship of nontraditional lipid indices with PAD in hypertensive patients.

METHODS

This cross-sectional study was performed among 10,900 adults with hypertension. Participants were diagnosed with PAD when their ankle-brachial index (ABI) was < 0.9. The association between nontraditional lipid profiles and PAD was examined using multivariate logistic regression analysis and the restricted cubic spline.

RESULTS

All nontraditional lipid indices were independently and positively associated with PAD in a dose-response fashion. After multivariable adjustment, the per SD increments of the TC/HDL-C, TG/HDL-C, LDL-C/HDL-C ratios and non-HDL-C were all significantly associated with 37, 14, 40, and 24% higher risk for PAD, respectively. The adjusted ORs (95% CI) for PAD were 1.77 (1.31, 2.40), 1.71 (1.25, 2.34), 2.03 (1.50, 2.74), and 1.70 (1.25, 2.31) when comparing the highest tertile to the lowest tertile of the TC/HDL-C, TG/HDL-C, LDL-C/HDL-C ratios and non-HDL-C, respectively.

CONCLUSIONS

Among Chinese hypertensive adults, all nontraditional lipid indices were positively associated with PAD, and the LDL-C/HDL-C and TC/HDL-C ratios were better than the other nontraditional lipid indices for predicting PAD. These findings may improve the risk stratification of cardiovascular disease and dyslipidemia management.

TRIAL REGISTRATION

CHiCTR, ChiCTR1800017274 . Registered 20 July 2018.

Indoxyl Sulfate and Incident Peripheral Artery Disease in Hemodialysis Patients

Peripheral artery disease (PAD) is highly prevalent among patients with chronic kidney disease (CKD) and portends a very poor prognosis. Indoxyl sulfate has been shown to induce atherothrombosis and impaired neovascularization in uremic mice. However, there is no clinical evidence regarding the role of indoxyl sulfate in PAD associated with CKD. We examined associations between indoxyl sulfate and incident symptomatic lower extremity PAD events as well as major adverse cardiovascular events (MACE) and all-cause mortality using Cox proportional hazards models in a prospective cohort of 200 hemodialysis patients free of PAD at baseline. Patients were considered as having PAD if they developed PAD symptoms confirmed by an ankle-brachial index with waveforms, duplex ultrasound or angiography, and/or major adverse limb events including revascularization and amputation. During a median follow-up of 6.5 years, 37 patients (18.5%) experienced incident symptomatic PAD. MACE occurred in 52 patients, and a total of 85 patients died. After adjusting for traditional risk factors for PAD, including age, current smoking, diabetes, and cardiovascular disease, indoxyl sulfate was significantly associated with the risk of PAD (hazard ratio (HR), 1.19 for every 10-μg/mL increase in indoxyl sulfate; 95% confidence interval (CI), 1.05–1.35). However, indoxyl sulfate was not associated with risk of MACE (HR, 1.00; 95% CI, 0.90–1.12) or death from any cause (HR, 0.98; 95% CI, 0.90–1.07). Indoxyl sulfate was associated with incident symptomatic PAD but not with MACE or all-cause mortality, suggesting that indoxyl sulfate toxicity may be unique to PAD among hemodialysis patients.

Investigation of the relationship between sensorineural hearing loss and associated comorbidities in patients with chronic kidney disease: A nationwide, population-based cohort study

Hearing impairment was observed in patients with chronic kidney disease (CKD). Our purpose was to investigate the relationship between sensorineural hearing loss (SNHL) and associated comorbidities in the CKD population. We conducted a retrospective, population-based study to examine the risk of developing SNHL in patients with CKD. Population-based data from 2000–2010 from the Longitudinal Health Insurance Database of the Taiwan National Health Insurance Research Database was used in this study. The population sample comprised 185,430 patients who were diagnosed with CKD, and 556,290 without CKD to determine SNHL risk factors. Cox proportional hazard regression analysis demonstrated the CKD group had a significantly increased risk of SNHL compared with the non-CKD group [adjusted hazard ratio (HR), 3.42; 95% confidence interval (CI), 3.01–3.90, p < 0.001]. In the CKD group, the risk of SNHL (adjusted HR, 5.92) was higher among patients undergoing hemodialysis than among those not undergoing hemodialysis (adjusted HR, 1.40). Furthermore, subgroup analysis revealed an increased risk of SNHL in patients with CKD and comorbidities, including heart failure (adjusted HR, 7.48), liver cirrhosis (adjusted HR, 4.12), type 2 diabetes mellitus (adjusted HR, 3.98), hypertension (adjusted HR, 3.67), and chronic obstructive pulmonary disease (adjusted HR, 3.45). CKD is an independent risk of developing SNHL. Additionally, hemodialysis for uremia can increase the risk of SNHL. Cardiovascular, lung, liver, and metabolic comorbidities in CKD patients may further aggravate the risk of SNHL by inter-organ crosstalk. We should pay attention to SNHL in this high-risk population.

Fibrosis and Inflammatory Markers and Long-Term Risk of Peripheral Artery Disease: The ARIC Study

OBJECTIVE

Inflammatory markers, such as hs-CRP (high-sensitivity C-reactive protein), have been reported to be related to peripheral artery disease (PAD). Galectin-3, a biomarker of fibrosis, has been linked to vascular remodeling and atherogenesis. However, its prospective association with incident PAD is unknown; as is the influence of inflammation on the association between galectin-3 and PAD. Approach and Results: In 9851 Atherosclerosis Risk in Communities Study participants free of PAD at baseline (1996-1998), we quantified the association of galactin-3 and hs-CRP with incident PAD (hospitalizations with PAD diagnosis [International Classification of Diseases-Ninth Revision: 440.2-440.4] or leg revascularization [eg, International Classification of Diseases-Ninth Revision: 38.18]) as well as its severe form, critical limb ischemia (PAD cases with resting pain, ulcer, gangrene, or leg amputation) using Cox models. Over a median follow-up of 17.4 years, there were 316 cases of PAD including 119 critical limb ischemia cases. Log-transformed galectin-3 was associated with incident PAD (adjusted hazard ratio, 1.17 [1.05-1.31] per 1 SD increment) and critical limb ischemia (1.25 [1.05-1.49] per 1 SD increment). The association was slightly attenuated after further adjusting for hs-CRP (1.14 [1.02-1.27] and 1.22 [1.02-1.45], respectively). Log-transformed hs-CRP demonstrated robust associations with PAD and critical limb ischemia even after adjusting for galectin-3 (adjusted hazard ratio per 1 SD increment 1.34 [1.18-1.52] and 1.34 [1.09-1.65], respectively). The addition of galectin-3 and hs-CRP to traditional atherosclerotic predictors (C statistic of the base model 0.843 [0.815-0.871]) improved the risk prediction of PAD (ΔC statistics, 0.011 [0.002-0.020]).

CONCLUSIONS

Galectin-3 and hs-CRP were independently associated with incident PAD in the general population, supporting the involvement of fibrosis and inflammation in the pathophysiology of PAD.

Systematic review and meta-analysis of outcomes of lower extremity peripheral arterial interventions in patients with and without chronic kidney disease or end-stage renal disease

OBJECTIVE

Patients with chronic kidney disease (CKD) have a greater risk of peripheral arterial disease (PAD). Although individual studies have documented an association between CKD and/or end-stage renal disease (ESRD) and adverse outcomes in patients undergoing PAD interventions in an era of technological advances in peripheral revascularization, the magnitude of the effect size is unknown. Therefore, we performed a meta-analysis to compare the outcomes of PAD interventions for patients with CKD/ESRD with those patients with normal renal function, stratified by intervention type (endovascular vs surgical), reflecting contemporary practice.

METHODS

Five databases were analyzed from January 2000 to June 2019 for studies that had compared the outcomes of lower extremity PAD interventions for patients with CKD/ESRD vs normal renal function. We included both endovascular and open interventions, with an indication of either claudication or critical limb ischemia. We analyzed the pooled odds ratios (ORs) across studies with 95% confidence intervals (CIs) using a random effects model. Funnel plot and exclusion sensitivity analyses were used for bias assessment.

RESULTS

Seventeen observational studies with 13,140 patients were included. All included studies, except for two, had accounted for unmeasured confounding using either multivariable regression analysis or case-control matching. The maximum follow-up period was 114 months (range, 0.5-114 months). The incidence of target lesion revascularization (TLR) was greater in those with CKD/ESRD than in those with normal renal function (OR, 1.68; 95% CI, 1.25-2.27; P = .001). The incidence of major amputations (OR, 1.97; 95% CI, 1.37-2.83; P < .001) and long-term mortality (OR, 2.28; 95% CI, 1.45-3.58; P < .001) was greater in those with CKD/ESRD. The greater TLR rates with CKD/ESRD vs normal renal function were only seen with endovascular interventions, with no differences for surgical interventions. The differences in rates of major amputations and long-term mortality between the CKD/ESRD and normal renal function groups were statistically significant, regardless of the intervention type.

CONCLUSIONS

Patients with CKD/ESRD who have undergone lower extremity PAD interventions had worse outcomes than those of patients with normal renal function. When stratifying our results by intervention (endovascular vs open surgery), greater rates of TLR for CKD/ESRD were only seen with endovascular and not with open surgical approaches. Major amputations and all-cause mortality were greater in the CKD/ESRD group, irrespective of the indication. Evidence-based strategies to manage this at-risk population who require PAD interventions are essential.

American Indian chronic Renal insufficiency cohort study (AI-CRIC study)

Background

Chronic kidney disease (CKD) is an increasing epidemic globally that is associated with adverse health outcomes including end stage kidney disease (ESKD), cardiovascular disease (CVD), and death. American Indians (AIs) have a higher prevalence of CKD than most other racial/ethnic groups, due in part to a high prevalence of type 2 diabetes. Other genetic and environmental factors not yet identified may also contribute to the disproportionate burden of CKD in AIs.

Method

We will establish 3 clinical centers to recruit AIs from the Southwest United States (US) to expand the Chronic Renal Insufficiency Cohort (CRIC) study. We will follow the current CRIC protocol for kidney and cardiovascular measures and outcomes, which include ambulatory monitoring of kidney function and the use of mobile health technologies for CVD sub-phenotyping, and compare the outcomes in AIs with those in other racial/ethnic groups in CRIC.

Discussion

AI-CRIC will identify the role of various risk factors for rapid loss of kidney function among AIs of the Southwest US. In addition, to better understand the natural history of CKD and CVD in this high-risk population, we will identify unique risk factors for CKD and CVD progression in AIs. We will also compare event rates and risk factors for kidney and cardiovascular events in AIs with the other populations represented in CRIC.

Impact of Kidney Disease on Peripheral Arterial Interventions: A Systematic Review and Meta-Analysis

BACKGROUND

There are limited data on outcomes of patients undergoing peripheral arterial disease (PAD) interventions who have comorbid CKD/ESRD versus those who do not have such comorbid condition. We performed a systematic review and meta-analysis to analyze outcomes in this patient population.

METHODS

Five databases were searched for studies comparing outcomes of lower extremity PAD interventions for claudication and critical limb ischemia (CLI) in patients with CKD/ESRD versus non-CKD/non-ESRD from January 2000 to June 2019.

RESULTS

Our study included 16 observational studies with 44,138 patients. Mean follow-up was 48.9 ± 27.4 months. Major amputation was higher with CKD/ESRD compared with non-CKD/non-ESRD (odds ratio [OR 1.97] [95% confidence interval [CI] 1.39-2.80], p = 0.001). Higher major amputations with CKD/ESRD versus non-CKD/non-ESRD were only observed when indication for procedure was CLI (OR 2.27 [95% CI 1.53-3.36], p < 0.0001) but were similar for claudication (OR 1.15 [95% CI 0.53-2.49], p = 0.72). The risk of early mortality was high with CKD/ESRD patients undergoing PAD interventions compared with non-CKD/non-ESRD (OR 2.55 [95% CI 1.65-3.96], p < 0.0001), which when stratified based on indication, remained higher with CLI (OR 3.14 [95% CI 1.80-5.48], p < 0.0001) but was similar with claudication (OR 1.83 [95% CI 0.90-3.72], p = 0.1). Funnel plot of included studies showed moderate bias.

CONCLUSIONS

Patients undergoing lower extremity PAD interventions for CLI who also have comorbid CKD/ESRD have an increased risk of experiencing major amputations and early mortality. Randomized trials to understand outcomes of PAD interventions in this at-risk population are essential.

The role of cigarette smoking on new-onset of chronic kidney disease in a Japanese population without prior chronic kidney disease: Iki epidemiological study of atherosclerosis and chronic kidney disease (ISSA-CKD)

BACKGROUND

Studies regarding harmful effects of smoking on the new-onset of chronic kidney disease (CKD) have been limited. Thus, we collected and retrospectively studied 8 years of data from the annual health check-ups of the residents in Iki City (Nagasaki Prefecture, Japan).

METHODS

From 2008 to 2016, 4540 adults were enrolled in the study. Information on smoking habits was obtained via a self-reported questionnaire. New-onset CKD was defined as a reduction of the estimated globular filtration rate (eGFR) to less than 60 mL/min/1.73 m² and/or new-onset proteinuria during the follow-up examinations.

RESULTS

During an average follow-up of 4.6 years, proteinuria developed in 218 people (10.4 per 1000 person-years) and eGFR decline to less than 60 mL/min/1.73 m² was confirmed in 594 people (28.3 per 1000 person-years) including 53 who showed both proteinuria and eGFR reduction (2.8 per 1000 person-years). In terms of proteinuria, current smokers showed a higher incidence than non-smokers (14.1 and 9.17 per 1000 person-years, respectively, p = 0.001), and a significantly high hazard ratio (HR) of 1.39 with a 95% CI of 1.01-1.92 in multivariable Cox's proportional-hazard analyses. The tendency was more drastic among younger participants (p = 0.015 for trend): current smokers who were < 50 years old had a significantly higher HR of 2.55 with a 95% CI of 1.01-6.45 (p = 0.004) than non-smokers.

CONCLUSIONS

Smoking significantly increased the risk for new-onset of CKD based on proteinuria development in a Japanese population without CKD, and the association was more predominant in the younger population.

Prognostic value of soluble ST2 and soluble LR11 on mortality and cardiovascular events in peritoneal dialysis patients

Background

Although the soluble form of suppression of tumorigenicity 2 (sST2) and soluble low-density lipoprotein receptor relative with 11 ligand-binding repeats (sLR11) have emerged as novel cardiovascular biomarkers in patients with cardiovascular disease, their prognostic value has not been fully investigated in peritoneal dialysis (PD) patients.

Methods

We included 74 prevalent PD patients from a prospective cohort and measured serum sST2 and sLR11 concentrations by an enzyme-linked immunosorbent assay. The association of these biomarkers and all-cause mortality and major adverse cardiac and cerebrovascular events (MACCEs) was evaluated.

Results

During a follow-up of 38.5 months, all-cause deaths and MACCEs were observed in 13 (17.6%) patients and 23 (31.3%) patients. Multivariable Cox analyses demonstrated that greater sST2 was independently associated with higher risk of all-cause mortality (≥75.8 ng/mL; hazard ratio [HR] = 5.551; 95% confidence interval [CI] = 1.360–22.660) and MACCEs (≥72.5 ng/mL; HR = 4.609; 95% CI = 1.608–13.208). Furthermore, sST2 showed additive predictive value for mortality to the base model including traditional risk factors (net reclassification index = 0.598, P = 0.04). sLR11 was not significantly associated with all-cause mortality or MACCE.

Conclusions

sST2, but not sLR11, indicated a significant prognostic value for all-cause mortality and cardiovascular events in PD patients. Further research is needed to validate emerging biomarkers in these populations.

High Sensitivity Troponin and Risk of Incident Peripheral Arterial Disease in Chronic Kidney Disease (from the Chronic Renal Insufficiency Cohort [CRIC] Study)

Patients with chronic kidney disease (CKD) are at increased risk for peripheral arterial disease (PAD). A novel biomarker to accurately and reliably predict new onset PAD in high risk patients is needed. High sensitivity troponin (HsTP) is a new assay which allows detection of very low troponin levels with high precision. We sought to explore the association between HsTP and risk of PAD in CKD. The Chronic Renal Insufficiency Cohort (CRIC) is a prospective cohort of 3,939 individuals with mild to moderate CKD using age related criteria for glomerular filtration rate. High sensitivity troponin T was measured at study enrollment. Patients with previous history of PAD or coronary artery disease were excluded. Patients were followed for new-onset adjudicated PAD, and the association between HsTP and incident PAD was examined. A total of 2,909 participants free of PAD and coronary artery disease at enrollment were included in this analysis. Over a mean follow up 7.4 years [interquartile ranges 5.8 to 8.5] years, 79 (2.7%) patients developed PAD. The 3-, 6-, and 9-year incidence of PAD was 1.00%, 2.03%, and 2.72%, respectively. At 9 years, the cumulative rates of PAD increased with HsTP (Quartile 1: 0.3%, Quartile 2: 2.4%, Quartile 3: 3.7%, Quartile 4: 10.7%; p <0.001). After adjusting for clinical risk factors of PAD, patients in the third quartile (Hazards ratio 5.89, 95% confidence interval: 1.31 to 26.47, p = 0.021) and fourth quartile of HsTP (Hazards ratio 10.24, 95% confidence interval 2.23 to 47.08, p = 0.003) had higher risk of PAD compared with lowest quartile of HsTP. HsTP had good discrimination of PAD at 3 years (area under the curve [AUC] 0.76), 6 years (AUC 0.79) and 9 years (AUC 0.80). Addition of HsTP to Framingham risk score improved model discrimination of PAD. In conclusion, in patients with mild-moderate CKD, HsTP levels are associated with and predictive of risk of incident PAD. This association remains significant despite adjustment for traditional PAD risk factors and chronic kidney disease.

Apabetalone lowers serum alkaline phosphatase and improves cardiovascular risk in patients with cardiovascular disease

BACKGROUND AND AIMS

In patients with cardiovascular disease, considerable residual risk remains despite evidence-based secondary prevention measures. Alkaline phosphatase (ALP) has been suggested as a modifiable cardiovascular risk factor. We sought to determine whether cardiovascular risk reduction by the bromodomain and extra-terminal (BET) protein inhibitor apabetalone is associated with the concomitant lowering of serum ALP.

METHODS

In a post-hoc analysis of 795 patients with established coronary heart disease and statin treatment, who participated in phase 2 placebo-controlled trials of apabetalone, we determined the effect of assigned treatment for up to 24 weeks on the incidence of major adverse cardiovascular events (MACE) and serum ALP.

RESULTS

Baseline ALP (median 72 U/L) predicted MACE (death, non-fatal myocardial infarction, coronary revascularization, or hospitalization for cardiovascular causes), independent of high-sensitivity C-reactive protein (hsCRP), sex, age, race, study, cardiovascular risk factors, chronic kidney disease (CKD), liver function markers and treatment allocation (hazard ratio [HR] per standard deviation [SD] 1.6, 95% CI 1.19-2.16, p = 0.002). Mean placebo-corrected decreases in ALP from baseline were 9.2% (p < 0.001) after 12-14 weeks and 7.7% (p < 0.001) after 24-26 weeks of apabetalone treatment. In the apabetalone group, a 1-SD reduction in ALP was associated with a HR for MACE of 0.64 (95% CI 0.46-0.90, p = 0.009).

CONCLUSIONS

Serum ALP predicts residual cardiovascular risk, independent of hsCRP, established cardiovascular risk factors and CKD, in patients with cardiovascular disease on statin treatment. Apabetalone lowers serum ALP, which was associated with a lower risk of cardiovascular events. Whether the beneficial cardiovascular effects of apabetalone are causally related to ALP reduction remains undetermined.

Positive Association of Serum Adipocyte Fatty Acid Binding Protein Level With Peripheral Artery Disease in Hemodialysis Patients

Adipocyte fatty acid binding protein is positively associated with atherosclerosis. Peripheral arterial disease is associated with an increased mortality in hemodialysis patients. This study aimed to evaluate the relationship between serum adipocyte fatty acid binding protein levels and peripheral arterial disease by ankle-brachial index in hemodialysis patients. Among the 90 chronic hemodialysis recipients, 20 patients (22.2%) were in the low ankle-brachial index group who had a higher prevalence of diabetes, hyperlipidemia, statin use, older age, higher body fat mass, higher serum adipocyte fatty acid binding protein level, and lower serum creatinine level compared with patients in the control group. After statistical analysis, body fat mass (P = 0.006) and creatinine level (P = 0.018) were shown to be the independent predictors of adipocyte fatty acid binding protein level. Serum adipocyte fatty acid binding protein (P = 0.021) was found to be positively associated with peripheral arterial disease in hemodialysis patients.

Atherosclerosis in Chronic Kidney Disease: More, Less, or Just Different?

Patients with chronic kidney disease (CKD) are at an increased risk of premature mortality, mainly from cardiovascular causes. The association between CKD on hemodialysis and accelerated atherosclerosis was described >40 years ago. However, more recently, it has been suggested that the increase in atherosclerosis risk is actually observed in early CKD stages, remaining stable thereafter. In this regard, interventions targeting the pathogenesis of atherosclerosis, such as statins, successful in the general population, have failed to benefit patients with very advanced CKD. This raises the issue of the relative contribution of atherosclerosis versus other forms of cardiovascular injury such as arteriosclerosis or myocardial injury to the increased cardiovascular risk in CKD. In this review, the pathophysiogical contributors to atherosclerosis in CKD that are shared with the general population, or specific to CKD, are discussed. The NEFRONA study (Observatorio Nacional de Atherosclerosis en NEFrologia) prospectively assessed the prevalence and progression of subclinical atherosclerosis (plaque in vascular ultrasound), confirming an increased prevalence of atherosclerosis in patients with moderate CKD. However, the adjusted odds ratio for subclinical atherosclerosis increased with CKD stage, suggesting a contribution of CKD itself to subclinical atherosclerosis. Progression of atherosclerosis was closely related to CKD progression as well as to the baseline presence of atheroma plaque, and to higher phosphate, uric acid, and ferritin and lower 25(OH) vitamin D levels. These insights may help design future clinical trials of stratified personalized medicine targeting atherosclerosis in patients with CKD. Future primary prevention trials should enroll patients with evidence of subclinical atherosclerosis and should provide a comprehensive control of all known risk factors in addition to testing any additional intervention or placebo.

Prevalence, clinical characteristics, and predictors of peripheral arterial disease in hemodialysis patients: a cross-sectional study

Background

Peripheral arterial disease (PAD) is common in patients with end-stage renal disease on hemodialysis, but is frequently underdiagnosed. The risk factors for PAD are well known within the general population, but they differ somewhat in hemodialysis patients. This study aimed to determine the prevalence of PAD and its risk factors in patients on hemodialysis.

Methods

This cross-sectional study included 156 hemodialysis patients. Comorbidities and laboratory parameters were analyzed. Following clinical examinations, the ankle-brachial index was measured in all patients. PAD was diagnosed based on the clinical findings, ankle-brachial index < 0.9, and PAD symptoms.

Results

PAD was present in 55 of 156 (35.3%; 95% CI, 27.7–42.8%) patients. The patients with PAD were significantly older (67 ± 10 years vs. 62 ± 11 years, p = 0.014), more likely to have diabetes mellitus (p = 0.022), and anemia (p = 0.042), and had significantly lower serum albumin (p = 0.005), total cholesterol (p = 0.024), and iron (p = 0.004) levels, higher glucose (p = 0.002) and C-reactive protein (p < 0.001) levels, and lower dialysis adequacies (p = 0.040) than the patients without PAD. Multivariate analysis showed higher C-reactive protein level (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.00–1.06; p = 0.030), vascular access by Hickman catheter (OR, 4.66; 95% CI, 1.03–21.0; p = 0.045), and symptoms of PAD (OR, 5.20; 95% CI, 2.60–10.4; p < 0.001) as independent factors associated with PAD in hemodialysis patients.

Conclusion

The prevalence of PAD was high among patients with end-stage renal disease on hemodialysis. Symptoms of PAD, higher C-reactive protein levels, and Hickman vascular access were independent predictors of PAD in patients on hemodialysis.

Unique aspects of peripheral artery disease in patients with chronic kidney disease

Peripheral artery disease (PAD) represents a major health care burden. Despite the advent of screening and interventional procedures, the long-term clinical outcomes remain suboptimal, especially in patients with chronic kidney disease (CKD). While CKD and PAD share common predisposing factors, emerging studies indicate that their co-existence is not merely an association; instead, CKD represents a strong, independent risk factor for PAD. These findings implicate CKD-specific mediators of PAD that remain incompletely understood. Moreover, there is a need to understand the mechanisms underlying poor outcomes after interventions for PAD in CKD. This review discusses unique clinical aspects of PAD in patients with CKD, including high prevalence and worse outcomes after vascular interventions and the influence of renal allograft transplantation. In doing so, it also highlights underappreciated aspects of PAD in patients with CKD, such as disparities in revascularization and higher peri-procedural mortality. While previous reviews have discussed general mechanisms of PAD pathogenesis, focusing on PAD in CKD, this review underscores a need to probe for CKD-specific pathogenic pathways that may unravel novel biomarkers and therapeutic targets in PAD and ultimately improve the risk stratification and management of patients with CKD and PAD.

Myeloperoxidase - A bridge linking inflammation and oxidative stress with cardiovascular disease

Myeloperoxidase (MPO) is a member of the superfamily of heme peroxidases that is mainly expressed in neutrophils and monocytes. MPO-derived reactive species play a key role in neutrophil antimicrobial activity and human defense against various pathogens primarily by participating in phagocytosis. Elevated MPO levels in circulation are associated with inflammation and increased oxidative stress. Multiple lines of evidence suggest an association between MPO and cardiovascular disease (CVD) including coronary artery disease, congestive heart failure, arterial hypertension, pulmonary arterial hypertension, peripheral arterial disease, myocardial ischemia/reperfusion-related injury, stroke, cardiac arrhythmia and venous thrombosis. Elevated MPO levels are associated with a poor prognosis including increased risk for overall and CVD-related mortality. Elevated MPO may signify an increased risk for CVD for at least 2 reasons. First, low-grade inflammation and increased oxidative stress coexist with many metabolic abnormalities and comorbidities and consequently an elevated MPO level may represent an increased cardiometabolic risk in general. Second, MPO produces a large number of highly reactive species which can attack, destroy or modify the function of every known cellular component. The most common MPO actions relevant to CVD are generation of dysfunctional lipoproteins with an increased atherogenicity potential, reduced NO availability, endothelial dysfunction, impaired vasoreactivity and atherosclerotic plaque instability. These actions strongly suggest that MPO is directly involved in the pathophysiology of CVD. In this regard MPO may be seen as a mediator or an instrument through which inflammation promotes CVD at molecular and cellular level. Clinical value of MPO therapeutic inhibition remains to be tested.

Apabetalone downregulates factors and pathways associated with vascular calcification

BACKGROUND AND AIMS

Apabetalone is an inhibitor of bromodomain and extraterminal (BET) proteins. In clinical trials, apabetalone reduced the incidence of major adverse cardiac events (MACE) in patients with cardiovascular disease and reduced circulating factors that promote vascular calcification (VC). Because VC contributes to MACE, effects of apabetalone on pro-calcific processes were examined.

METHODS AND RESULTS

Apabetalone inhibited extracellular calcium deposition and opposed induction of transdifferentiation markers in human coronary artery vascular smooth muscle cells (VSMCs) under osteogenic culture conditions. Tissue-nonspecific alkaline phosphatase (TNAP) is a key contributor to VC, and apabetalone suppressed osteogenic induction of the mRNA, protein and enzyme activity. The liver is a major source of circulating TNAP, and apabetalone also downregulated TNAP expression in primary human hepatocytes. BRD4, a transcriptional regulator and target of apabetalone, has been linked to calcification. Osteogenic transdifferentiation of VSMCs resulted in disassembly of 100 BRD4-rich enhancers, with concomitant enlargement of remaining enhancers. Apabetalone reduced the size of BRD4-rich enhancers, consistent with disrupting BRD4 association with chromatin. 38 genes were uniquely associated with BRD4-rich enhancers in osteogenic conditions; 11 were previously associated with calcification. Apabetalone reduced levels of BRD4 on many of these enhancers, which correlated with decreased expression of the associated gene. Bioinformatics revealed BRD4 may cooperate with 7 specific transcription factors to promote transdifferentiation and calcification.

CONCLUSIONS

Apabetalone counters transdifferentiation and calcification of VSMCs via an epigenetic mechanism involving specific transcription factors. The mechanistic findings, combined with evidence from clinical trials, support further development of apabetalone as a therapeutic for VC.

Association between albumin and C-reactive protein and ankle-brachial index in haemodialysis

AIM

Peripheral artery occlusive disease (PAOD) is associated with increased rates of cardiovascular mortality, morbidity and hospitalization in patients undergoing dialysis. An ankle-brachial index (ABI) less than 0.9 has been used to diagnose PAOD. The aim of this study was to evaluate associations among inflammation, malnutrition and their interactions on the risk of PAOD.

METHODS

Two hundred and twenty-two haemodialysis patients (mean age 61.0 ± 11.7 years, 56.8% men) were enrolled and stratified into four groups according to median values of albumin (3.87 g/dL) and logarithm of C-reactive protein (CRP) (0.48 mg/L). Associations between the study groups and an ABI less than 0.9 were assessed using multiple logistic regression analysis. Receiver operating characteristic curves were constructed to predict an ABI less than 0.9.

RESULTS

A lower level of albumin and higher level of CRP were significantly associated with an ABI less than 0.9 in multivariate analysis (odds ratio, 5.688; 95% confidence interval, 1.369-23.626; P = 0.017) after adjusting for demographic, clinical, biochemical and medication data. The interaction between albumin and CRP in relation to an ABI less than 0.9 was significant in multivariate analysis (odds ratio, 1.797; 95% confidence interval, 1.258-2.568; P = 0.001). The areas under the curve for albumin, CRP and albumin + CRP for the prediction of ABI less than 0.9 were 0.311, 0.654 and 0.733, respectively.

CONCLUSION

Patients undergoing haemodialysis with a lower albumin level and higher CRP level have an increased risk of PAOD. A combination of malnutrition and inflammation may be associated with PAOD in haemodialysis patients.

Alkaline Phosphatases in the Complex Chronic Kidney Disease-Mineral and Bone Disorders

Alkaline phosphatases (APs) remove the phosphate (dephosphorylation) needed in multiple metabolic processes (from many molecules such as proteins, nucleotides, or pyrophosphate). Therefore, APs are important for bone mineralization but paradoxically they can also be deleterious for other processes, such as vascular calcification and the increasingly known cross-talk between bone and vessels. A proper balance between beneficial and harmful activities is further complicated in the context of chronic kidney disease (CKD). In this narrative review, we will briefly update the complexity of the enzyme, including its different isoforms such as the bone-specific alkaline phosphatase or the most recently discovered B1x. We will also analyze the correlations and potential discrepancies with parathyroid hormone and bone turnover and, most importantly, the valuable recent associations of AP's with cardiovascular disease and/or vascular calcification, and survival. Finally, a basic knowledge of the synthetic and degradation pathways of APs promises to open new therapeutic strategies for the treatment of the CKD-Mineral and Bone Disorder (CKD-MBD) in the near future, as well as for other processes such as sepsis, acute kidney injury, inflammation, endothelial dysfunction, metabolic syndrome or, in diabetes, cardiovascular complications. However, no studies have been done using APs as a primary therapeutic target for clinical outcomes, and therefore, AP's levels cannot yet be used alone as an isolated primary target in the treatment of CKD-MBD. Nonetheless, its diagnostic and prognostic potential should be underlined.

Assessment of Renal Function and Risk Factors for Chronic Kidney Disease in Patients With Peripheral Arterial Disease

Chronic kidney disease (CKD) and peripheral arterial disease (PAD) share common risk factors. We assessed renal function and the prevalence of CKD in patients with PAD and investigated the characteristics of the risk factors for CKD in this population. Renal function of 421 patients with PAD was evaluated. Among the participants, 194 (46.1%) patients had decreased estimated glomerular filtration rate (eGFR). The prevalence of CKD was much higher among patients with PAD. Hypertension (odds ratios [ORs] 2.156, 95% confidence interval [CI] 1.413-3.289, P < .001), serum uric acid (OR 3.794, 95% CI 2.220-6.450, P < .001), and dyslipidemia (OR 1.755, 95% CI 1.123-2.745, P = .014) were significantly associated with CKD and the independent risk factors for CKD in patients with PAD. CKD is common and has a high prevalence in a population with PAD. Patients with PAD may be considered as a high-risk population for CKD. Recognition and modification of risk factors for CKD might beneficially decrease CKD incidence and improve prognosis in patients with PAD.