Kidney Disease and Cardiovascular Risk

Echocardiographic manifestations in end-stage renal disease

End-stage renal disease (ESRD) is a common but profound clinical condition, and it is associated with extremely increased morbidity and mortality. ESRD can represent four major echocardiographic findings-myocardial hypertrophy, heart failure, valvular calcification, and pericardial effusion. Multiple factors interplay leading to these abnormalities, including pressure/volume overload, oxidative stress, and neurohormonal imbalances. Uremic cardiomyopathy is characterized by left ventricular (LV) hypertrophy and marked diastolic dysfunction. In ESRD patients on hemodialysis, LV geometry is changeable bidirectionally between concentric and eccentric hypertrophy, depending upon changes in corporal fluid volume and arterial pressure, which eventually results in a characteristic of LV systolic dysfunction. Speckle tracking echocardiography enabling to detect subclinical disease might help prevent future advancement to heart failure. Heart valve calcification also is common in ESRD, keeping in mind which progresses faster than expected. In a modern era, pericardial effusion observed in ESRD patients tends to result from volume overload, rather than pericarditis. In this review, we introduce and discuss those four echocardiography-assessed findings of ESRD, with which known and conceivable pathophysiologies for each are incorporated.

Demystifying the connection between periodontal disease and chronic kidney disease - An umbrella review

Chronic kidney disease (CKD) and poor oral health are inter-related and their significant impact on each other is well established in the literature. Many systematic reviews and meta-analyses have demonstrated a strong relationship between CKD and periodontitis, where periodontal treatment has shown potential in improving CKD outcomes. However, the quality of the studies and heterogeneity of the results show variation. The aim of this umbrella review was to review the quality of the current systematic reviews on the relationship between CKD and oral health with an emphasis on periodontal disease and to generate clinically relevant guidelines to maintain periodontal health in patients with CKD. This umbrella review was conducted and reported in alignment with the Joanna Briggs Institute and the PRISMA 2020 guidelines. The review protocol was established prior to commencing the review and registered on JBI and PROSPERO (CRD42022335209). Search strings were established for PubMed, Embase, Web of Science, Cochrane Database of Systematic Reviews, and Dentistry & Oral Science Source up to April 2022. All systematic reviews and meta-analyses that considered the relationship between CKD and periodontitis or periodontal treatment were included. Of 371 studies identified through the systematic search, 18 systematic reviews met the inclusion criteria. Ten studies assessed the relationship between oral health status and CKD with a focus on periodontitis and CKD, five reviewed the impact of periodontal treatment on CKD outcomes, two included both relationship and effectiveness of periodontal treatment and one qualitatively reviewed oral health-related quality of life in patients with kidney failure. Findings indicate there is a bidirectional relationship between CKD and periodontal disease. In view of the heterogeneity of the existing literature on CKD and periodontal disease, specific recommendations for the management of periodontitis among patients with CKD are proposed for medical professionals, dental professionals, and aged care workers based on the evidence collated in this review.

Sex-specific interactive effect of melamine and DEHP on a marker of early kidney damage in Taiwanese adults: A national population-based study from the Taiwan Biobank

Taiwan had the high incidence of chronic kidney disease (CKD) worldwide. Our objective was to examine associations between daily exposure of phthalates and melamine, two common nephrotoxins, and kidney damage risk in a well-established nationwide cohort. Study subjects were from Taiwan Biobank (TWB) with existing data of questionnaire and biochemical examinations. Average daily intake (ADI) levels of melamine and seven parental phthalates, including DEHP (di-2-ethylhexylphthalate), DiBP (Dibutyl phthalate), DnBP (Di-n-butyl phthalate), BBzP (Butyl benzyl phthalate), DEP (Diethyl phthalate), and DMP (Dimethyl phthalate) were estimated using a creatinine excretion-based model from urine melamine and 10 phthalate metabolites. Urine microalbumin to creatinine ratio (ACR) was used to represent for the outcome of kidney damage. Two statistical strategies were used: First, a weighted quantile sum (WQS) regression model to select the most important exposure variables of ADI levels of phthalates and melamine associated with ACR; Second, to examine effects of those most important exposure variables on ACR in multivariable linear regression models. In total, 1153 eligible adults were left for analyses. Of them, 591 (51.3%) and 562 (48.7%) were men and women, respectively, with a median age of 49 years old. By WQS, a significant and positive association was found between ADI of melamine and phthalates and ACR (β = 0.14, p = 0.002). ADI levels of melamine had the highest weight (0.57), followed by DEHP (0.13). Next, examining the two most important exposures in association with ACR, we found that the higher the melamine and DEHP intakes, the higher the ACR levels were found. An interaction effect was also found between melamine and DEHP intakes on urine ACR (p = 0.015). This result was more prominent in men (p = 0.008) than in women (p = 0.651). Environmental co-exposure of melamine and DEHP can potentially affect ACR in the community-dwelling Taiwanese adult population.

Pericardial Tamponade and Berger's Disease: An Unusual Association

Cardiac tamponade is considered a medical emergency because a patient can deteriorate easily and die of cardiac arrest if the fluid is not drained immediately. The most common etiologies are the same as pericarditis as fluid accumulates due to pericardial inflammation, including infection, malignancy, trauma, iatrogenic, autoimmune, post-myocardial infarction, radiation, and renal failure. Although the treatment is pericardiocentesis or pericardial window, finding the etiology responsible for the development of pericardial effusion is important. Here, we describe the case of a 40-year-old female who presented to the emergency department with a chief complaint of severe epigastric pain of a two-day duration that was associated with multiple episodes of nausea, vomiting, dysphagia, and severe shortness of breath (New York Heart Association III). The patient was eventually diagnosed with cardiac tamponade as a cause of her dyspnea, as a two-dimensional cardiac echocardiogram detected a large pericardial effusion (>2 cm) with echocardiographic indications for cardiac tamponade with severe pulmonary hypertension. The patient underwent a therapeutic pericardial window with drainage of 250 mL of pericardial fluid. Ultrasound of the abdomen focusing on the kidneys showed an atrophic and echogenic right kidney with a bidirectional flow in the hepatic veins, suggestive of right heart failure. Subsequently, she underwent a kidney biopsy that showed diffuse mesangial proliferative glomerulonephritis with segmental sclerosing features consistent with IgA nephropathy, associated with tubular atrophy, interstitial fibrosis, interstitial inflammation, and moderate arteriosclerosis. The patient was diagnosed with stage V chronic kidney disease secondary to IgA nephropathy. IgA nephropathy is usually common in Caucasian or Asian males in their teens and late 30s, with hematuria as a usual presentation. This case is unique as cardiac tamponade with renal failure is rarely the presenting symptom of IgA nephropathy.

Vascular calcification in CKD: New insights into its mechanisms

Vascular calcification (VC) is a common complication of chronic kidney disease (CKD) and contributes to an increased risk of cardiovascular morbidity and mortality. However, effective therapies are still unavailable at present. It has been well established that VC associated with CKD is not a passive process of calcium phosphate deposition, but an actively regulated and cell-mediated process that shares many similarities with bone formation. Additionally, numerous studies have suggested that CKD patients have specific risk factors and contributors to the development of VC, such as hyperphosphatemia, uremic toxins, oxidative stress and inflammation. Although research efforts in the past decade have greatly improved our knowledge of the multiple factors and mechanisms involved in CKD-related VC, many questions remain unanswered. Moreover, studies from the past decade have demonstrated that epigenetic modifications abnormalities, such as DNA methylation, histone modifications and noncoding RNAs, play an important role in the regulation of VC. This review seeks to provide an overview of the pathophysiological and molecular mechanisms of VC associated with CKD, mainly focusing on the involvement of epigenetic modifications in the initiation and progression of uremic VC, with the aim to develop promising therapies for CKD-related cardiovascular events in the future.

Systematic Review and Meta-Analyses of the Effects of Phosphate-Lowering Agents in Nondialysis CKD

BACKGROUND

Benefits of phosphate-lowering interventions on clinical outcomes in patients with CKD are unclear; systematic reviews have predominantly involved patients on dialysis. This study aimed to summarize evidence from randomized controlled trials (RCTs) concerning benefits and risks of noncalcium-based phosphate-lowering treatment in nondialysis CKD.

METHODS

We conducted a systematic review and meta-analyses of RCTs involving noncalcium-based phosphate-lowering therapy compared with placebo, calcium-based binders, or no study medication, in adults with CKD not on dialysis or post-transplant. RCTs had ≥3 months follow-up and outcomes included biomarkers of mineral metabolism, cardiovascular parameters, and adverse events. Outcomes were meta-analyzed using the Sidik-Jonkman method for random effects. Unstandardized mean differences were used as effect sizes for continuous outcomes with common measurement units and Hedge's g standardized mean differences (SMD) otherwise. Odds ratios were used for binary outcomes. Cochrane risk of bias and GRADE assessment determined the certainty of evidence.

RESULTS

In total, 20 trials involving 2498 participants (median sample size 120, median follow-up 9 months) were eligible for inclusion. Overall, risk of bias was low. Compared with placebo, noncalcium-based phosphate binders reduced serum phosphate (12 trials, weighted mean difference -0.37; 95% CI, -0.58 to -0.15 mg/dl, low certainty evidence) and urinary phosphate excretion (eight trials, SMD -0.61; 95% CI, -0.90 to -0.31, low certainty evidence), but resulted in increased constipation (nine trials, log odds ratio [OR] 0.93; 95% CI, 0.02 to 1.83, low certainty evidence) and greater vascular calcification score (three trials, SMD, 0.47; 95% CI, 0.17 to 0.77, very low certainty evidence). Data for effects of phosphate-lowering therapy on cardiovascular events (log OR, 0.51; 95% CI, -0.51 to 1.17) and death were scant.

CONCLUSIONS

Noncalcium-based phosphate-lowering therapy reduced serum phosphate and urinary phosphate excretion, but there was an unclear effect on clinical outcomes and intermediate cardiovascular end points. Adequately powered RCTs are required to evaluate benefits and risks of phosphate-lowering therapy on patient-centered outcomes.

Framing Cause-Effect Relationship of Acute Coronary Syndrome in Patients with Chronic Kidney Disease

The main causes of death in patients with chronic kidney disease (CKD) are of cardiovascular nature. The interaction between traditional cardiovascular risk factors (CVRF) and non-traditional risk factors (RF) triggers various complex pathophysiological mechanisms that will lead to accelerated atherosclerosis in the context of decreased renal function. In terms of mortality, CKD should be considered equivalent to ischemic coronary artery disease (CAD) and properly monitored. Vascular calcification, endothelial dysfunction, oxidative stress, anemia, and inflammatory syndrome represents the main uremic RF triggered by accumulation of the uremic toxins in CKD subjects. Proteinuria that appears due to kidney function decline may initiate an inflammatory status and alteration of the coagulation—fibrinolysis systems, favorizing acute coronary syndromes (ACS) occurrence. All these factors represent potential targets for future therapy that may improve CKD patient’s survival and prevention of CV events. Once installed, the CAD in CKD population is associated with negative outcome and increased mortality rate, that is the reason why discovering the complex pathophysiological connections between the two conditions and a proper control of the uremic RF are crucial and may represent the solutions for influencing the prognostic. Exclusion of CKD subjects from the important trials dealing with ACS and improper use of the therapeutical options because of the declined kidney functioned are issues that need to be surpassed. New ongoing trials with CKD subjects and platelets reactivity studies offers new perspectives for a better clinical approach and the expected results will clarify many aspects.

Kv1.3 Channel Inhibition Limits Uremia-Induced Calcification in Mouse and Human Vascular Smooth Muscle

Chronic kidney disease (CKD) significantly increases cardiovascular risk. In advanced CKD stages, accumulation of toxic circulating metabolites and mineral metabolism alterations triggers vascular calcification, characterized by vascular smooth muscle cell (VSMC) transdifferentiation and loss of the contractile phenotype. Phenotypic modulation of VSMC occurs with significant changes in gene expression. Even though ion channels are an integral component of VSMC function, the effects of uremia on ion channel remodeling has not been explored. We used an in vitro model of uremia-induced calcification of human aorta smooth muscle cells (HASMCs) to study the expression of 92 ion channel subunit genes. Uremic serum-induced extensive remodeling of ion channel expression consistent with loss of excitability but different from the one previously associated with transition from contractile to proliferative phenotypes. Among the ion channels tested, we found increased abundance and activity of voltage-dependent K+ channel Kv1.3. Enhanced Kv1.3 expression was also detected in aorta from a mouse model of CKD. Pharmacological inhibition or genetic ablation of Kv1.3 decreased the amount of calcium phosphate deposition induced by uremia, supporting an important role for this channel on uremia-induced VSMC calcification.

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.

Relations of advanced glycation endproducts and dicarbonyls with endothelial dysfunction and low-grade inflammation in individuals with end-stage renal disease in the transition to renal replacement therapy: A cross-sectional observational study

Background

Cardiovascular disease (CVD) related mortality and morbidity are high in end-stage renal disease (ESRD). The pathophysiology of CVD in ESRD may involve non-traditional CVD risk factors, such as accumulation of advanced glycation endproducts (AGEs), dicarbonyls, endothelial dysfunction (ED) and low-grade inflammation (LGI). However, detailed data on the relation of AGEs and dicarbonyls with ED and LGI in ESRD are limited.

Methods

We examined cross-sectional Spearman’s rank correlations of AGEs and dicarbonyls with serum biomarkers of ED and LGI in 43 individuals with chronic kidney disease (CKD) stage 5 not on dialysis (CKD5-ND). Free and protein-bound serum AGEs (N^∈-(carboxymethyl)lysine (CML), N^∈-(carboxyethyl)lysine (CEL), N_δ-(5-hydro-5-methyl-4-imidazolon-2-yl)ornithine (MG-H1)) and serum dicarbonyls (glyoxal, methylglyoxal, 3-deoxyglucosone) were analyzed with tandem mass spectrometry, and tissue AGE accumulation was estimated by skin autofluorescence (SAF). Further, serum biomarkers of ED and LGI included sVCAM-1, sE-selectin, sP-selectin, sThrombomodulin, sICAM-1, sICAM-3, hs-CRP, SAA, IL-6, IL-8 and TNF-α.

Results

After adjustment for age, sex and diabetes status, protein-bound CML was positively correlated with sVCAM-1; free CEL with sVCAM-1 and sThrombomodulin; glyoxal with sThrombomodulin; and methylglyoxal with sVCAM-1 (correlation coefficients ranged from 0.36 to 0.44). In addition, free CML was positively correlated with SAA; protein-bound CML with IL-6; free CEL with hs-CRP, SAA and IL-6; free MG-H1 with SAA; protein-bound MG-H1 with IL-6; and MGO with hs-CRP and IL-6 (correlation coefficients ranged from 0.33 to 0.38). Additional adjustment for eGFR attenuated partial correlations of serum AGEs and serum dicarbonyls with biomarkers of ED and LGI.

Conclusions

In individuals with CKD5-ND, higher levels of serum AGEs and serum dicarbonyls were related to biomarkers of ED and LGI after adjustment for age, sex and diabetes mellitus. Correlations were attenuated by eGFR, suggesting that eGFR confounds and/or mediates the relation of serum AGEs and dicarbonyls with ED and LGI.

An update on possible pathogenic mechanisms of periodontal pathogens on renal dysfunction

Periodontitis is a potential source of permanent systemic inflammation that initiates renal dysfunction and contributes to the development of chronic kidney diseases (CKDs). Although numerous studies have confirmed the bidirectional role of periodontal infection and renal inflammation, no literature has yet highlighted the sophisticated pathogenic mechanisms by which periodontal pathogens, particularly Porphynomonas Gingivalis, induce renal dysfunction and contributed in the development of CKDs. The present review aims to critically analyze and highlight the novel pathogenesis of periodontitis induced CKDs.

Amount and pattern of physical activity and sedentary behavior are associated with kidney function and kidney damage: The Maastricht Study

Background

Chronic kidney disease, which is defined as having a reduced kidney function (estimated glomerular filtration rate (eGFR)) and/or signs of kidney damage (albuminuria), is highly prevalent in Western society and is associated with adverse health outcomes, such as cardiovascular disease. This warrants a search for risk factors of lower eGFR and higher albuminuria. Physical activity and sedentary behavior may be such risk factors.

Objective

To examine associations of physical activity (total, high, low), sedentary time and sedentary behavior patterns (breaks, prolonged bouts, average bout duration) with eGFR and albuminuria.

Methods

We examined these associations in 2,258 participants of the Maastricht Study (average age 60.1±8.1 years; 51.3% men), who wore an accelerometer 24h/day on 7 consecutive days. Associations with continuous eGFR and categories of urinary albumin excretion (UAE; <15 [reference category], 15-<30, ≥30 mg/24h) were evaluated with linear regression analyses and multinomial logistic regression analyses, respectively.

Results

After adjustment for potential confounders, each extra hour of total physical activity was associated with a more favorable kidney function (beta_eGFR = 2.30 (95%CI = 1.46; 3.14)), whereas each extra hour of sedentary behavior was associated with a more adverse kidney function (beta_eGFR = -0.71 (-1.08; -0.35)). Also, compared to individuals with the lowest levels of total physical activity, individuals with the highest levels had less kidney damage (OR_15-<30mg/24h = 0.63 (0.41; 0.96), OR_≥30mg/24h = 0.84 (0.53; 1.35). An extra hour of sedentary behavior was associated with more kidney damage (OR_{15-<30 mg/24h} = 1.11 (1.01; 1.22), OR_{≥30 mg/24h} = 1.10 (0.99; 1.22)). Further, a highly sedentary pattern was associated with a more adverse kidney function, but no association was seen with kidney damage.

Conclusions

Physical activity and sedentary behavior were associated with kidney function and kidney damage. Additionally, sedentary behavior patterns were associated with kidney function. Causal studies are required to examine whether this indeed implicates that prevention strategies should focus not only on increasing physical activity, but on reducing sedentary behavior as well.

Deleterious effects of phosphate on vascular and endothelial function via disruption to the nitric oxide pathway

Background

Hyperphosphataemia is an independent risk factor for accelerated cardiovascular disease in chronic kidney disease (CKD), although the mechanism for this is poorly understood. We investigated the effects of sustained exposure to a high-phosphate environment on endothelial function in cellular and preclinical models, as well as in human subjects.

Methods

Resistance vessels from rats and humans (± CKD) were incubated in a normal (1.18 mM) or high (2.5 mM) phosphate concentration solution and cells were cultured in normal- (0.5 mM) or high-phosphate (3 mM) concentration media. A single-blind crossover study was performed in healthy volunteers, receiving phosphate supplements or a phosphate binder (lanthanum), and endothelial function measured was by flow-mediated dilatation.

Results

Endothelium-dependent vasodilatation was impaired when resistance vessels were exposed to high phosphate; this could be reversed in the presence of a phosphodiesterase-5-inhibitor. Vessels from patients with CKD relaxed normally when incubated in normal-phosphate conditions, suggesting that the detrimental effects of phosphate may be reversible. Exposure to high-phosphate disrupted the whole nitric oxide pathway with reduced nitric oxide and cyclic guanosine monophosphate production and total and phospho endothelial nitric oxide synthase expression. In humans, endothelial function was reduced by chronic phosphate loading independent of serum phosphate, but was associated with higher urinary phosphate excretion and serum fibroblast growth factor 23.

Conclusions

These directly detrimental effects of phosphate, independent of other factors in the uraemic environment, may explain the increased cardiovascular risk associated with phosphate in CKD.

Phenotypic Modulation of Cultured Primary Human Aortic Vascular Smooth Muscle Cells by Uremic Serum

Patients with chronic kidney disease (CKD) have a markedly increased incidence of cardiovascular disease (CVD). The high concentration of circulating uremic toxins and alterations in mineral metabolism and hormone levels produce vascular wall remodeling and significant vascular damage. Medial calcification is an early vascular event in CKD patients and is associated to apoptosis or necrosis and trans-differentiation of vascular smooth muscle cells (VSMC) to an osteogenic phenotype. VSMC obtained from bovine or rat aorta and cultured in the presence of increased inorganic phosphate (Pi) have been extensively used to study these processes. In this study we used human aortic VSMC primary cultures to compare the effects of increased Pi to treatment with serum obtained from uremic patients. Uremic serum induced calcification, trans-differentiation and phenotypic remodeling even with normal Pi levels. In spite of similar calcification kinetics, there were fundamental differences in osteochondrogenic marker expression and alkaline phosphatase induction between Pi and uremic serum-treated cells. Moreover, high Pi induced a dramatic decrease in cell viability, while uremic serum preserved it. In summary, our data suggests that primary cultures of human VSMC treated with serum from uremic patients provides a more informative model for the study of vascular calcification secondary to CKD.

Uremic pericarditis, pericardial effusion, and constrictive pericarditis in end-stage renal disease: Insights and pathophysiology

A rising prevalence of end-stage renal disease (ESRD) has led to a rise in ESRD-related pericardial syndromes, calling for a better understanding of its pathophysiology, diagnoses, and management. Uremic pericarditis, the most common manifestation of uremic pericardial disease, is a contemporary problem that calls for intensive hemodialysis, anti-inflammatories, and often, drainage of large inflammatory pericardial effusions. Likewise, asymptomatic pericardial effusions can become large and impact the hemodynamics of patients on chronic hemodialysis. Constrictive pericarditis is also well documented in this population, ultimately resulting in pericardiectomy for definitive treatment. The management of pericardial diseases in ESRD patients involves internists, cardiologists, and nephrologists. Current guidelines lack clarity with respect to the management of pericardial processes in the ESRD population. Our review aims to describe the etiology, classification, clinical manifestations, diagnostic imaging tools, and treatment options of pericardial diseases in this population.

Kidney and innate immunity

Innate immune system is an important modulator of the inflammatory response during infection and tissue injury/repair. The kidney as a vital organ with high energy demand plays a key role in regulating the disease related metabolic process. Increasing research interest has focused on the immune pathogenesis of many kidney diseases. However, innate immune cells such as dendritic cells, macrophages, NK cells and a few innate lymphocytes, as well as the complement system are essential for renal immune homeostasis and ensure a coordinated balance between tissue injury and regeneration. The innate immune response provides the first line of host defense initiated by several classes of pattern recognition receptors (PRRs), such as membrane-bound Toll-like receptors (TLRs) and nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs), together with inflammasomes responsible for early innate immune response. Although the innate immune system is well studied, the research on the detailed relationship between innate immunity and kidney is still very limited. In this review, we will focus on the innate immune sensing system in renal immune homeostasis, as well as the corresponding pathogenesis of many kidney diseases. The pivotal roles of innate immunity in renal injury and regeneration with special emphasis on kidney disease related immunoregulatory mechanism are also discussed.

Electrolyte and Acid-Base Disorders in Chronic Kidney Disease and End-Stage Kidney Failure

The kidneys play a pivotal role in the regulation of electrolyte and acid-base balance. With progressive loss of kidney function, derangements in electrolytes and acid-base inevitably occur and contribute to poor patient outcomes. As chronic kidney disease (CKD) has become a worldwide epidemic, medical providers are increasingly confronted with such problems. Adequate diagnosis and treatment will minimize complications and can potentially be lifesaving. In this review, we discuss the current understanding of the disease process, clinical presentation, diagnosis and treatment strategies, integrating up-to-date knowledge in the field. Although electrolyte and acid-base derangements are significant causes of morbidity and mortality in CKD and end-stage renal disease patients, they can be effectively managed through a timely institution of combined preventive measures and pharmacological therapy. Exciting advances and several upcoming outcome trials will provide further information to guide treatment and improve patient outcomes.

Endothelial maintenance in health and disease: Importance of sex differences

The vascular endothelium has emerged as more than just an inert monolayer of cells lining the vascular bed. It represents the interface between the blood stream and vessel wall, and has a strategic role in regulating vascular homeostasis by the release of vasoactive substances. Endothelial dysfunction contributes to the development and progression of cardiovascular disease. Recognition of sex-specific factors implicated in endothelial cell biology is important for the identification of clinically relevant preventive and/or therapeutic strategies. This review aims to give an overview of the recent advances in understanding the importance of sex specific observations in endothelial maintenance, both in healthy and diseased conditions. The female endothelium is highlighted in the context of polycystic ovary syndrome and pre-eclampsia. Furthermore, sex differences are explored in chronic kidney disease, which is currently appreciated as one of public health priorities. Overall, this review endorses integration of sex analysis in experimental and patient-oriented research in the exciting field of vascular biology.

Incidence and Risk of Cardiac Events in Patients With Previously Treated Multiple Myeloma Versus Matched Patients Without Multiple Myeloma: An Observational, Retrospective, Cohort Study

BACKGROUND

Multiple myeloma (MM) patients have age-, disease-, and treatment-related risk factors for cardiac events.

MATERIALS AND METHODS

We analyzed the 2006 to 2011 MarketScan database to determine whether the risk of cardiac events is greater in MM patients than in non-MM patients. Included were 1723 MM patients treated with corticosteroids and ≥ 3 drugs (bortezomib, immunomodulatory derivatives, and alkylating agents or anthracyclines). The index date (ID) was the date on which the 3-drug exposure criterion was met. Also included were 8615 age- and gender-matched non-MM patients (5:1). The distribution of non-MM patients' IDs matched that of the MM patients' IDs. Baseline was 6 months before the ID. The follow-up duration was from the ID to study end (ie, 2011 or end of enrollment or prescription drug coverage). Hazard ratios (HRs) and 95% confidence intervals (CIs) were adjusted for baseline variables when the univariate analyses showed a 10% difference.

RESULTS

The median duration of observation was 9 months (range, 0-60 months) for MM patients and 19 months (range, 0-66 months) for non-MM patients. The risk of any cardiac event (HR, 2.2; 95% CI, 1.9-2.5), dysrhythmia (HR, 4.1; 95% CI, 3.5-4.8), congestive heart failure (HR, 2.9; 95% CI, 2.2-3.7), cardiomyopathy (HR, 2.6; 95% CI, 1.8-3.8), and conduction disorders (HR, 1.7; 95% CI, 1.2-2.5) was significantly greater for MM than for non-MM patients. The incidence of hypertensive or arterial events and ischemic heart disease was similar between the 2 groups.

CONCLUSION

The present study provides the first known comparison of cardiac event risk in patients with MM versus age- and gender-matched patients without MM. The cardiac event risk was greater in MM patients with ≥ 3 previous drugs for any cardiac event, dysrhythmias, congestive heart failure, cardiomyopathy, and conduction disorders compared with patients without MM.

Effect of mineralocorticoid receptor antagonists on proteinuria and progression of chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Hypertension and proteinuria are critically involved in the progression of chronic kidney disease. Despite treatment with renin angiotensin system inhibition, kidney function declines in many patients. Aldosterone excess is a risk factor for progression of kidney disease. Hyperkalaemia is a concern with the use of mineralocorticoid receptor antagonists. We aimed to determine whether the renal protective benefits of mineralocorticoid antagonists outweigh the risk of hyperkalaemia associated with this treatment in patients with chronic kidney disease.

METHODS

We conducted a meta-analysis investigating renoprotective effects and risk of hyperkalaemia in trials of mineralocorticoid receptor antagonists in chronic kidney disease. Trials were identified from MEDLINE (1966-2014), EMBASE (1947-2014) and the Cochrane Clinical Trials Database. Unpublished summary data were obtained from investigators. We included randomised controlled trials, and the first period of randomised cross over trials lasting ≥4 weeks in adults.

RESULTS

Nineteen trials (21 study groups, 1 646 patients) were included. In random effects meta-analysis, addition of mineralocorticoid receptor antagonists to renin angiotensin system inhibition resulted in a reduction from baseline in systolic blood pressure (-5.7 [-9.0, -2.3] mmHg), diastolic blood pressure (-1.7 [-3.4, -0.1] mmHg) and glomerular filtration rate (-3.2 [-5.4, -1.0] mL/min/1.73 m(2)). Mineralocorticoid receptor antagonism reduced weighted mean protein/albumin excretion by 38.7 % but with a threefold higher relative risk of withdrawing from the trial due to hyperkalaemia (3.21, [1.19, 8.71]). Death, cardiovascular events and hard renal end points were not reported in sufficient numbers to analyse.

CONCLUSIONS

Mineralocorticoid receptor antagonism reduces blood pressure and urinary protein/albumin excretion with a quantifiable risk of hyperkalaemia above predefined study upper limit.

Reduction of potassium content of green bean pods and chard by culinary processing. Tools for chronic kidney disease

INTRODUCTION

In order to prevent a possible hyperkalemia, chronic renal patients, especially in advanced stages, must follow a low potassium diet. So dietary guidelines for chronic kidney disease recommend limiting the consumption of many vegetables, as well as to apply laborious culinary techniques to maximize the reduction of potassium.

OBJECTIVE

The aim of this work is to analyze potassium content from several vegetable, fresh products, frozen and preserved, as well as check and compare the effectiveness in potassium reduction of different culinary processes, some of them recommended in dietary guidelines such as soaking or double cooking.

METHODS

Sample potassium content was analyzed by triplicate using flamephotometry.

RESULTS

The results showed significant reductions in potassium content in all culinary processes studied. The degree of loss varied depending on the type of vegetable and processing applied. Frozen products achieved greater reductions than the fresh ones, obtaining in some cases losses greater than 90%. In addition, it was observed how in many cases the single application of a normal cooking reached potassium reductions to acceptable levels for its inclusion in renal patient diet.

CONCLUSION

The results shown in this study are very positive because they provide tools for professionals who deal with this kind of patients. They allow them to adapt more easily to the needs and preferences of their patients and increase dietary variety.

Klotho Prevents Translocation of NFκB

Klotho protein is a β-glucuronidase capable of hydrolyzing steroid β-glucuronides. Two molecules are produced by the Klotho gene, a membrane bound form and a circulating form. This protein is recognized as an antiaging gene with pleiotropic functions. The activation of cellular systems is associated with the pathogenesis of several chronic and degenerative diseases associated with an inflammatory state. Inflammation is characterized by an activation of NFκB. Klotho suppresses nuclear factor NFκB activation and the subsequent transcription of proinflammatory genes. This review focuses on the current understanding of Klotho protein function and its relationship with NFκB regulation, emphasizing its potential involvement in the pathophysiologic process.

Managing older patients with hemophilia

With access to safe factor products, the life expectancy of persons with hemophilia (PWHs) has increased almost 10-fold over the past 7 decades. Unfortunately, hand in hand with this success comes the burden of aging. As PWHs age, they are subject to develop many of the same risk factors as the general population, including increasing rates of hypertension, obesity, and diabetes. Such comorbidities predispose them to chronic diseases, such as cardiovascular disease and chronic kidney disease, although how their coagulopathy affects the expression of these conditions remains unclear. The older hemophilia population faces additional challenges, such as chronic joint arthropathy, which provokes falls and fractures, and complications related to HIV and hepatitis C infections, which greatly affect the incidence of cancer and liver disease. In light of the paucity of evidence-based guidelines to direct therapy, a new challenge has arisen for hematologists to optimally manage these complex age-related issues. In general, elderly PWHs should be treated similarly to their peers without hemophilia, with the addition of factor replacement therapy as appropriate. Primary prevention of risk factors should be emphasized, and close coordination between specialties is essential. This review will focus on common complications affecting the older hemophilia population, including cardiovascular disease, malignancy, liver disease, renal insufficiency, and joint disease.

Prevalence and management of chronic kidney disease in primary care patients in the UK

BACKGROUND

This study aimed to estimate the prevalence of chronic kidney disease (CKD) in the UK in 2010 and to assess prevalence, comorbidities and comedications associated with the disease over time, following inclusion of CKD in the Quality and Outcomes Framework (QOF).

METHODS

This was a retrospective, longitudinal study assessing individuals with prevalent or incident CKD (identified using estimated glomerular filtration rate readings and/or Read codes) in the General Practice Research Database (GPRD) in 2010. Individuals were assessed at two time points: in 2010 and at the date of their first classification of CKD in the GPRD.

RESULTS

The prevalence of stage 3-5 CKD in 2010 was 5.9%. In patients with stage 3-5 CKD at first classification, their disease remained stable, progressed or improved by 2010 in approximately 50%, 10-15% and 25-30% of patients, respectively. Diagnoses of cardiovascular-related comorbidities (hypertension, hypercholesterolaemia, diabetes and cardiovascular disease), and treatment with antihypertensives and lipid-modifying therapy (LMT), increased with worsening disease severity. When patients were stratified by diagnosis date, the proportion of patients with stage 3-5 CKD and cardiovascular-related comorbidities decreased with time, and the relative use of LMT and antihypertensives among patients with hypercholesterolaemia and hypertension increased with time.

CONCLUSIONS

Chronic kidney disease is generally stable or progressive, although more patients improve disease stage than previously assumed. Data suggest that the introduction of CKD into the QOF has increased awareness of CKD among physicians in the UK, allowing for earlier intervention and better control of CKD progression.

The Relationship between Soluble Tumor Necrosis Factor-like Weak Inducer of Apoptosis Levels and Cardiac Functions in Peritoneal Dialysis Patients

Tumor necrosis factor (TNF)-like weak inducer of apoptosis (sTWEAK) levels has been reported to be decreased in patients on hemodialysis (HD) and patients with heart failure. We aimed to study the relationship between sTWEAK levels and cardiac functions in peritoneal dialysis (PD) patients. This cross-sectional study was carried out on patients on chronic PD programs for more than three months. Patients aged under 18 or over 80 years, patients with overt cardiac disease, overt hypervolemia, active systemic infection, malignancy, peritonitis within the last month were excluded. The patient group was compared with the control group including healthy adults aged 24–61 years. Fifty-two PD patients were included in the study (mean age: 52.7±15.4 years; female/male ratio: 30/22). The corresponding data of the control group were 41.3±10.7 years and 17/14. There was no statistically significant difference between demographic parameters of the groups except age. The mean sTWEAK level of the patient and the control groups were similar (564±17 pcg/ml vs 535±126 pcg/ml, p=0.419). No correlation was detected between any of the demographic variables and sTWEAK levels. Among the echocardiographic parameters, only ejection fraction was found to be correlated negatively with sTWEAK levels. Patients with ischemic heart disease (IHD) and heart failure had significantly higher sTWEAK levels compared with the patients without these diseases. With linear regression analysis, only age and the presence of heart failure were found to be the independent determinants of sTWEAK levels. Level of sTWEAK is significantly high in PD patients with heart failure and IHD. sTWEAK may be a marker of cardiac functions in PD patients.

Impact of mild to moderate reductions of glomerular filtration rate on coronary artery disease severity

BACKGROUND & AIMS

The bases of the link between reduced glomerular filtration rate (GFR) and coronary artery disease (CAD) are complex and to some extent still unclear. We performed this observational, single referral center, cohort study to evaluate whether mild to moderate GFR reduction is associated with more severe CAD and/or with a worse cardiac prognosis independently of proteinuria, diabetes and traditional risk factors.

METHODS AND RESULTS

In 1752 consecutive non-diabetic patients without proteinuria or moderate/severe kidney disease undergoing a clinically driven coronary angiography, coronary arteries lesions, myocardial function and hypertrophy and 10-yrs incidence of cardiac events and death were evaluated in relation to classes of estimated GFR defined according the lowest eGFR value (105+, 90+, 75+, 60+, 45+). A reduced eGFR was independently associated with hypertension, myocardial hypertrophy and stress induced ischemia, while the excess coronary lesions and the worse myocardial systolic function were both largely explained by age and cardiovascular risk factors. When compared to subjects 75+, both the risk of cardiac death (1.67[1.10-2.57] and 3.06[1.85-5.10]) and non-fatal myocardial infarction (2.58[1.12-6.49] and 2.73[1.31-6.41]) adjusted for age and comorbidities were higher in eGFR 60+ and 45+ patients.

CONCLUSIONS

A mild-moderate reduction of eGFR is closely associated to higher rates of stress-induced ischemia, myocardial hypertrophy and higher risk of fatal and non-fatal cardiac events. The associations of reduced eGFR with coronary atherosclerosis and myocardial systolic dysfunction are both largely explained by age and traditional risk factors.

The periodontal health component of the Renal Impairment In Secondary Care (RIISC) cohort study: a description of the rationale, methodology and initial baseline results

INTRODUCTION

Chronic kidney disease (CKD) is associated with significant morbidity and mortality. There is a need to identify novel and modifiable risk factors in such patients. The periodontal component of the Renal Impairment In Secondary Care (RIISC) study aims to evaluate the association between chronic periodontitis and CKD progression.

METHODS

The RIISC study is a prospective, observational cohort study of patients with CKD from a renal clinic at a hospital in the West Midlands region of the UK. Patients undergo a periodontal examination and plaque and saliva sampling. To benchmark the oral health status of the RIISC cohort, we compared it to the Adult Dental Health Survey 2009 (ADHS), a representative survey of the oral health of community dwelling adults in the UK.

RESULTS

Of the first 500 patients recruited into the RIISC study, 469 patients underwent a dental examination and 80 (17%) were edentulous. Among dentate subjects, patients within RIISC were significantly more likely to have any (OR 4.0 95% CI 2.7-5.9) or severe (OR 3.8 95% CI 2.5-5.6) periodontitis compared to the ADHS sample.

CONCLUSION

The prevalence and severity of chronic periodontitis in this cohort of CKD patients is markedly higher than a geographically matched control population.

Periodontal disease: a covert source of inflammation in chronic kidney disease patients

The prevalence of atherosclerotic complications (myocardial infarction, stroke, and sudden death) is increased in end-stage renal disease (ESRD) patients, especially in haemodialysis patients. Increasing evidence suggests that both in general population and in dialysis patients, systemic inflammation plays a dominant role in the pathogenesis of atherosclerotic complications. In general population, also, evidence shows that moderate to severe periodontitis can contribute to inflammatory burden by increasing serum CRP levels and may increase the prevalence of atherosclerotic events. Moreover, the results of some new interventional studies reveal that effective phase I periodontal therapy may decrease serum CRP levels, the most important acute phase protein, monitored as a systemic marker of inflammation and endothelial dysfunction as well, used as an initial predictor of atherosclerotic events. Considering that moderate to severe periodontal diseases have a higher prevalence in CKD and in dialysis population and that periodontal examination is not part of the standard medical assessment, destructive periodontitis might be an ignored source of systemic inflammation in end-stage renal disease patients and may add to the chronic inflammatory status in CKD.

The natural history of, and risk factors for, progressive chronic kidney disease (CKD): the Renal Impairment in Secondary care (RIISC) study; rationale and protocol

BACKGROUND

Chronic kidney disease (CKD) affects up to 16% of the adult population and is associated with significant morbidity and mortality. People at highest risk from progressive CKD are defined by a sustained decline in estimated glomerular filtration rate (eGFR) and/or the presence of significant albuminuria/proteinuria and/or more advanced CKD. Accurate mapping of the bio-clinical determinants of this group will enable improved risk stratification and direct the development of better targeted management for people with CKD.

METHODS/DESIGN

The Renal Impairment In Secondary Care study is a prospective, observational cohort study, patients with CKD 4 and 5 or CKD 3 and either accelerated progression and/or proteinuria who are managed in secondary care are eligible to participate. Participants undergo a detailed bio-clinical assessment that includes measures of vascular health, periodontal health, quality of life and socio-economic status, clinical assessment and collection of samples for biomarker analysis. The assessments take place at baseline, and at six, 18, 36, 60 and 120 months; the outcomes of interest include cardiovascular events, progression to end stage kidney disease and death.

DISCUSSION

The determinants of progression of chronic kidney disease are not fully understood though there are a number of proposed risk factors for progression (both traditional and novel). This study will provide a detailed bio-clinical phenotype of patients with high-risk chronic kidney disease (high risk of both progression and cardiovascular events) and will repeatedly assess them over a prolonged follow up period. Recruitment commenced in Autumn 2010 and will provide many outputs that will add to the evidence base for progressive chronic kidney disease.

Impact of hepatitis C on survival in dialysis patients: a link with cardiovascular mortality?

Recent evidence has been accumulated showing that anti-HCV-positive serologic status is significantly associated with lower survival in dialysis populations, but the mechanisms underlying this negative relationship are still unclear. The aim of this study was to conduct a systematic review of the published medical literature concerning the impact of hepatitis C virus (HCV) infection on all-cause and disease-specific mortality of patients on regular dialysis. The relative risk of all-cause, cardiovascular and liver disease-related mortality was regarded as the most reliable outcome end-point. Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random effect pooled estimates for mortality with HCV across the published studies. We identified fourteen observational studies involving 145 608 unique patients on long-term dialysis. Pooling of study results demonstrated that anti-HCV antibody was an independent and significant risk factor for death in patients on maintenance dialysis. The summary estimate for adjusted relative risk (all-cause mortality) was 1.35 with a 95% confidence interval (CI) of 1.25-1.47. Stratified analysis showed that the adjusted RR for liver disease-related death was 3.82 (95% CI, 1.92; 7.61); heterogeneity statistics, R(i) = 0.58 (P-value by Q-test = 0.087). The adjusted RR for cardiovascular mortality was 1.26 (95% CI, 1.10; 1.45); no heterogeneity was found (NS). This meta-analysis of observational studies indicates that anti-HCV-positive patients on dialysis have an increased risk of either liver or cardiovascular disease-related mortality compared with anti-HCV-negative patients. Further studies are in progress to understand better the link between HCV and cardiovascular risk among patients on maintenance dialysis.

Urinary corticosteroid excretion predicts left ventricular mass and proteinuria in chronic kidney disease

Blockade of the MR (mineralocorticoid receptor) in CKD (chronic kidney disease) reduces LVMI [LV (left ventricular) mass index] and proteinuria. The MR can be activated by aldosterone, cortisol and DOC (deoxycorticosterone). The aim of the present study was to explore the influence of mineralocorticoids on LVMI and proteinuria in patients with CKD. A total of 70 patients with CKD and 30 patients with EH (essential hypertension) were recruited. Patients underwent clinical phenotyping; biochemical assessment and 24 h urinary collection for THAldo (tetrahydroaldosterone), THDOC (tetrahydrodeoxycorticosterone), cortisol metabolites (measured using GC–MS), and urinary electrolytes and protein [QP (proteinuira quantification)]. LVMI was measured using CMRI (cardiac magnetic resonance imaging). Factors that correlated significantly with LVMI and proteinuria were entered into linear regression models. In patients with CKD, significant predictors of LVMI were male gender, SBP (systolic blood pressure), QP, and THAldo and THDOC excretion. Significant independent predictors on multivariate analysis were THDOC excretion, SBP and male gender. In EH, no association was seen between THAldo or THDOC and LVMI; plasma aldosterone concentration was the only significant independent predictor. Significant univariate determinants of proteinuria in patients with CKD were THAldo, THDOC, USod (urinary sodium) and SBP. Only THAldo excretion and SBP were significant multivariate determinants. Using CMRI to determine LVMI we have demonstrated that THDOC is a novel independent predictor of LVMI in patients with CKD, differing from patients with EH. Twenty-four hour THAldo excretion is an independent determinant of proteinuria in patients with CKD. These findings emphasize the importance of MR activation in the pathogenesis of the adverse clinical phenotype in CKD.

Aldosterone blockade and the mineralocorticoid receptor in the management of chronic kidney disease: current concepts and emerging treatment paradigms

The past two decades have witnessed a striking paradigm shift with respect to our understanding of the widespread effects of aldosterone. There is substantive evidence that mineralocorticoid receptor (MR) activation promotes myriad 'off target' effects on the heart, the vasculature, and importantly the kidney. In the present review, we summarize the expanding role of MR activation in promoting both vascular and renal injury. We review the recent clinical studies that investigated the efficacy of MR antagonism (MRA) in reducing proteinuria and attenuating progressive renal disease. We also review in-depth both the utility and safety of MRA in the end-stage renal disease (ESRD) patient undergoing dialysis. Because the feasibility of add-on MRA is critically dependent on our ability to minimize or avoid hyperkalemia, and because controversy centers on the incidence of hyperkalemia, we critically review the risk of hyperkalemia with add-on MRA. Our present analysis suggests that hyperkalemia supervening in MRA-treated patients is overstated. Furthermore, recent studies demonstrating the efficacy of new non-absorbed, orally administered, potassium [K+]-binding polymers suggest that a multi-pronged approach encompassing adequate surveillance, moderate or low-dose MRA, and K-binding polymers may adequately control serum K in both chronic kidney disease and ESRD patients.

Serum amyloid A in uremic HDL promotes inflammation

Uremia impairs the atheroprotective properties of HDL, but the mechanisms underlying why this occurs are unknown. Here, we observed that HDL isolated from healthy individuals inhibited the production of inflammatory cytokines by peripheral monocytes stimulated with a Toll-like receptor 2 agonist. In contrast, HDL isolated from the majority of patients with ESRD did not show this anti-inflammatory property; many HDL samples even promoted the production of inflammatory cytokines. To investigate this difference, we used shotgun proteomics to identify 49 HDL-associated proteins in a uremia-specific pattern. Proteins enriched in HDL from patients with ESRD (ESRD-HDL) included surfactant protein B (SP-B), apolipoprotein C-II, serum amyloid A (SAA), and α-1-microglobulin/bikunin precursor. In addition, we detected some ESRD-enriched proteins in earlier stages of CKD. We did not detect a difference in oxidation status between HDL isolated from uremic and healthy patients. Regarding function of these uremia-specific proteins, only SAA mimicked ESRD-HDL by promoting inflammatory cytokine production. Furthermore, SAA levels in ESRD-HDL inversely correlated with its anti-inflammatory potency. In conclusion, HDL has anti-inflammatory activities that are defective in uremic patients as a result of specific changes in its molecular composition. These data suggest a potential link between the high levels of inflammation and cardiovascular mortality in uremia.

Chronic kidney disease

Chronic kidney disease is a general term for heterogeneous disorders affecting kidney structure and function. The 2002 guidelines for definition and classification of this disease represented an important shift towards its recognition as a worldwide public health problem that should be managed in its early stages by general internists. Disease and management are classified according to stages of disease severity, which are assessed from glomerular filtration rate (GFR) and albuminuria, and clinical diagnosis (cause and pathology). Chronic kidney disease can be detected with routine laboratory tests, and some treatments can prevent development and slow disease progression, reduce complications of decreased GFR and risk of cardiovascular disease, and improve survival and quality of life. In this Seminar we discuss disease burden, recommendations for assessment and management, and future challenges. We emphasise clinical practice guidelines, clinical trials, and areas of uncertainty.

Proteinuria: an ignored marker of inflammation and cardiovascular disease in chronic hemodialysis

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in hemodialysis (HD) patients, the main etiologies being diabetes and hypertension. Cardiac and inflammatory biomarkers are usually employed to assess risk or damage, or during follow-up. Proteinuria is considered a strong predictor of morbidity, a cause of inflammation, oxidative stress, hemodynamic alteration, and progression of chronic kidney disease. However, proteinuria is rarely considered in the clinical assessment of HD patients.

METHODS

This was a concurrent, cohort-observational, cross-sectional study in which 52 chronic HD subjects were divided into three groups according to the degree of proteinuria: Group (G) A: <1 g/day, n = 25; GB: 1-3 g/day, n = 13; GC: >3 g/day, n = 14. Baseline hemoglobin, albuminemia, cholesterol, body mass index, Malnutrition-Inflammatory Score, pro-B-type natriuretic peptide, troponin T, C-reactive protein (CRP), and ultrafiltration rates were analyzed.

RESULTS

There was no difference between groups in terms of baseline age, gender, hypertension, cause of renal failure, hemoglobin, cholesterol, albumin, CRP levels, cardiac biomarkers, adiponectin, body mass index, or Malnutrition-Inflammatory Score. Time on HD: GA, 34.56 ± 23.3 (range [r]: 6-88); GB, 25.15 ± 19.40 (r: 6-58); GC, 18.21 ± 9.58 (r: 6-74) months; P = 0.048. Proteinuria: GA, 0.33 ± 0.30 (r: 0.0-0.88); GB, 1.66 ± 0.54 (r: 1.03-2.75); GC, 7.18 ± 2.80 (r: 3.04-21.5) g/day; P < 0.001. Mean ultrafiltration rates were significantly different: GA, 2.80 ± 0.73; GB: 1.85 ± 0.96 liters/session; P = 0.003. Fourteen diabetic patients were identified (27%): GA, 3 (12%); GB, 3 (23%); GC, 8 (57%); P = 0.009. A positive and significant correlation was observed between diabetes and proteinuria >3 g/day: rho 0.438, P = 0.027. Although troponin T, pro-B-type natriuretic peptide, adiponectin, and CRP were not different among groups, the positive correlation between troponin T and CRP elevated significantly as proteinuria increased: GA, rho 377, P = 0.063; GB, rho 663, P = 0.013; GC, rho 687, P = 0.007.

CONCLUSION

In chronic HD, nephrotic-range proteinuria was significantly higher in diabetic nephropathy patients versus other causes. This was associated with inflammation and cardiac stress and was independent of fluid removal. Proteinuria >3 g/day was associated with shorter time on HD. Whether severe proteinuria is associated with shorter survival in HD, independent of diabetes, is to be determined. Proteinuria should be considered in the assessment of cardiovascular and inflammatory states in HD patients.

Vascular proteomics and the discovery process of clinical biomarkers: The case of TWEAK

In the last years, big efforts are devoted to the search of novel biomarkers. Proteomic approaches in healthy and pathological samples may help us to discern differential protein expression patterns. These identified proteins include potential culprits in pathological pathways and/or clinical biomarkers to identify individuals at risk. However, extensively validation must be carried out before their implementation into the clinical practice. Biomarkers need to discriminate between health and disease, detect preclinical disease stages, have impact on survival prediction, and add predictive value beyond traditional risk factors and global risk algorithms. Now, we summarize the data of soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK), a new cardiovascular biomarker identified by proteomic analysis. Decreased sTWEAK concentrations have been shown in patients with carotid atherosclerosis, coronary artery disease, congestive heart failure, peripheral artery disease, or chronic kidney disease (CKD). sTWEAK predicted adverse outcomes in patients with heart failure, myocardial infarction, and CKD. Finally, different drug regimens were able to modify sTWEAK plasma levels in patients with CKD. Although sTWEAK seems so far to fulfill the requisites in the development of a new biomarker, more large-scale studies are warranted to consolidate its usefulness.

Fetal, developmental, and parental influences on cystatin C in childhood: the Uppsala Family Study

BACKGROUND

The aim was to identify determinants (biomedical and social characteristics of children and their parents) of cystatin C levels in healthy children drawn from a population sample.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

425 pairs of consecutive full siblings born 1987-1995 in Uppsala were identified using the Swedish Medical Birth Registry and invited with their parents for examination in 2000-2001.

OUTCOME

Serum cystatin C level was log-transformed and analyzed using random-effects models.

MEASUREMENTS

The examination in parents and children consisted of a nonfasting blood sample, anthropometry, and questionnaires about lifestyle and socioeconomic position. Tanner stage was used for assessment of pubertal status.

RESULTS

In age-, height-, and body mass index-adjusted analyses, cystatin C level increased by 2.6% (95% CI, 0.3%-4.8%) higher in Tanner stage 2 vs 1 girls, and 1.6% (95%CI, 0.2%-3.1%) lower in boys than girls. For every 10% increase in maternal cystatin C level, offspring cystatin C level increased by 3.0% (95% CI, 2.2%-3.8%); the equivalent effect for paternal cystatin C level was 2.1% (95% CI, 1.3%-2.9%). Lower maternal education was associated with a 2.4% (95% CI, 0.3%-4.6%) higher cystatin C level in their offspring.

LIMITATIONS

Cross-sectional study design, missing cystatin C values for subset of parents, lack of urinary measurements, no gold-standard measurement of glomerular filtration rate.

CONCLUSIONS

There are intergenerational associations of cystatin C level in families in line with previous reports of heritability of kidney disease. Lower maternal education is associated with higher cystatin C levels in their children. Further studies of healthy children are needed to explore the biological mechanisms for these findings. If cystatin C is measured, these studies will need to record pubertal stages.

Cardiovascular and renal outcomes with telmisartan, ramipril, or both in people at high renal risk: results from the ONTARGET and TRANSCEND studies

BACKGROUND

In the Ongoing Telmisartan Alone and in Combination With Ramipril Global End Point Trial (ONTARGET), dual therapy did not reduce cardiovascular or renal outcomes compared with either angiotensin-converting enzyme inhibitors or angiotensin receptor blockers alone. Previous controlled trials with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers have demonstrated greater cardiovascular and renal benefit in people with renal risk. We hypothesized that dual therapy would be more effective than monotherapy in patients with low glomerular filtration rate and elevated albuminuria.

METHODS AND RESULTS

Post hoc analysis was performed of renal subgroups of dual therapy versus monotherapy for the ONTARGET study and angiotensin receptor blocker versus placebo for the Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease (TRANSCEND). The studies featured hazard ratios by subgroups and Cox regression models with factors for treatment, subgroup, and interactions. The main cardiovascular outcome was the composite of cardiovascular death, myocardial infarction, stroke, or hospitalization for heart failure, and the main renal outcome was the composite of chronic dialysis or doubling of creatinine. In ONTARGET, there was no cardiovascular or renal benefit from dual over monotherapy in any subgroup, even with low glomerular filtration rate and/or elevated albuminuria. In TRANSCEND, in the comparison of angiotensin receptor blocker with placebo, there was a significant interaction for the main renal outcome (P = 0.01) in the direction of harm for patients with normoalbuminuria (0.37 versus 0.16 events per 100 patient-years; hazard ratio, 2.35; confidence interval, 1.33 to 4.15) but a trend to benefit with microalbuminuria (0.52 versus 0.89 events per 100 patient-years; hazard ratio, 0.60; confidence interval, 0.25 to 1.46) and macroalbuminuria (1.57 versus 2.60 events per 100 patient-years; hazard ratio, 0.71; confidence interval, 0.21 to 2.44).

CONCLUSIONS

This post hoc analysis does not support dual therapy over monotherapy in high-vascular risk patients with low glomerular filtration rate or albuminuria. This observation is a post hoc comparison and should be interpreted appropriately.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov Identifier: NCT00153101.

Periodontal disease as a risk marker in coronary heart disease and chronic kidney disease

PURPOSE OF REVIEW

More than half a million Americans die each year from coronary heart disease (CHD), 26 million suffer from chronic kidney disease (CKD), and a large proportion have periodontal disease, a chronic infection of the tissues surrounding teeth. Chronic inflammation contributes to CHD and CKD occurrence and progression, and periodontal disease contributes to the cumulated chronic systemic inflammatory burden. This review examines recent evidence regarding the role of periodontal disease in CHD and CKD.

RECENT FINDINGS

Periodontal pathogens cause both local infection and bacteremia, eliciting local and systemic inflammatory responses. Periodontal disease is associated with the systemic inflammatory reactant C-reactive protein (CRP), a major risk factor for both CHD and CKD. Nonsurgical periodontal disease treatment is shown to improve periodontal health, endothelial function, levels of CRP, and other inflammatory markers. Evidence for the association of periodontal disease with CKD consists of a small body of literature represented mainly by cross-sectional studies. No definitive randomized controlled trials exist with either CHD or CKD as primary endpoints.

SUMMARY

Recent evidence links periodontal disease with CHD and CKD. Adding oral health self-care and referral for professional periodontal assessment and therapy to the repertoire of medical care recommendations is prudent to improve patients' oral health and possibly reduce CHD and CKD risk.

Bidirectional relationship between chronic kidney and periodontal disease: a study using structural equation modeling

Periodontal disease is associated with diabetes, heart disease, and chronic kidney disease (CKD), relationships postulated to be due in part to vascular inflammation. A bidirectional relationship between CKD and periodontal disease is plausible, though this relationship has not been previously reported. In this study, we assessed the potential for connections between CKD and periodontal disease, and mediators of these relationships using structural equation models of data from 11,211 adults ≥ 18 years of age who participated in the Third National Health and Nutrition Examination Survey. Multivariable logistic regression models were used to test the hypothesis that periodontal disease was independently associated with CKD. Given the potential that the periodontal disease and CKD relationship may be bidirectional, a two-step analytic approach was used that involved tests for mediation and structural equation models to examine more complex direct and indirect effects of periodontal disease on CKD, and vice versa. In two separate models, periodontal disease (adjusted odds ratio of 1.62), edentulism (adjusted odds ratio of 1.83), and the periodontal disease score were associated with CKD when simultaneously adjusting for 14 other factors. Altogether, three of four structural equation models support the hypothesized relationship. Thus, our analyses support a bidirectional relationship between CKD and periodontal disease, mediated by hypertension and the duration of diabetes.

Soluble TWEAK plasma levels as a novel biomarker of endothelial function in patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Recently, we showed that soluble TNF-like weak inducer of apoptosis (sTWEAK) plasma levels are diminished in hemodialysis patients and had additive effects with IL-6 on survival. Because sTWEAK plasma level has been associated with the presence of chronic kidney disease (CKD) and cardiovascular disease, we hypothesized that in patients with CKD, sTWEAK levels may relate to the increased prevalence of endothelial dysfunction that usually accompanies the decline of estimated GFR (eGFR).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 295 patients with different stages of nondiabetic CKD (52% male; age 47 +/- 12 yr), testing the association between sTWEAK plasma levels and CKD stage and the relationship between flow-mediated dilation (FMD) and sTWEAK concentrations. Fifty-five healthy volunteers (51% male; age 47 +/- 11 yr) served as matched control subjects.

RESULTS

A gradual decrease in FMD was observed as eGFR decreased. Compared with healthy control subjects, sTWEAK plasma levels were diminished in all stages of CKD and correlated strongly with eGFR. FMD levels were associated with sTWEAK concentrations in univariate analysis. This association persisted after multivariate adjustment for eGFR levels, high-sensitivity C-reactive protein, diastolic BP, and sTWEAK, all of which were found to be significant and independent contributors to FMD.

CONCLUSIONS

A decline in eGFR is accompanied by gradual reductions in sTWEAK plasma levels. Because sTWEAK strongly and independently correlated with FMD, our study suggests novel links between sTWEAK and endothelial dysfunction in patients with CKD.

Additive effects of soluble TWEAK and inflammation on mortality in hemodialysis patients

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is characterized by an exceptionally high mortality rate, primarily due to cardiovascular disease. Reduced soluble TNF-like weak inducer of apoptosis (sTWEAK) plasma levels have been reported both in patients with subclinical atherosclerosis and CKD.

DESIGN, PARTICIPANTS, & MEASUREMENTS

A cross-sectional study was conducted in 218 prevalent patients (121 men; 63 +/- 14 yr) undergoing hemodialysis (HD). sTWEAK levels in relation with the patients' outcome were studied.

RESULTS

sTWEAK plasma levels were 208 [(165 to 272) pg/ml, median interquartile range], significantly lower than healthy controls (P < 0.0001). sTWEAK was negatively associated with inflammatory markers, such as C-reactive protein and IL-6. Overall mortality was assessed after an average follow-up of 31 mo, during which 81 patients died. After controlling for potential confounding variables, patients in the upper tertile of sTWEAK plasma levels had an increased risk of cardiovascular and all-cause mortality. A significant interaction effect between sTWEAK and IL-6 levels was found [synergy index: 2.19 (0.80, 5.93)]. Thus, the association of sTWEAK with mortality was strongest in patients with inflammation (defined as IL-6 > 7.0 pg/ml), in whom high sTWEAK strongly predicted cardiovascular and all-cause mortality. These results were confirmed in a second cohort of HD patients.

CONCLUSIONS

The concurrent presence of elevated sTWEAK plasma concentrations and an inflammatory environment have additive effects on mortality in HD patients. Further studies on the potential different role of sTWEAK in health and disease are warranted.

The association between kidney function, coronary artery disease, and clinical outcome in patients undergoing coronary angiography

To characterize the association between chronic kidney disease (CKD), mortality, severity of coronary artery disease (CAD), treatment modality of CAD, and type of coronary stents among patients undergoing coronary angiography (CAG), we retrospectively reviewed the electronic medical records of the patients who underwent CAG at Seoul National University Bundang Hospital in Korea between May 2003 and January 2006. CKD was staged using an estimated glomerular filtration rate (eGFR) from the creatinine value prior to CAG. There were 3,637 patients included. The presence of CAD was 48% in CKD stage 1, 61% in stage 2, 73% in stage 3, 87% in stage 4, and 81% in stage 5. Survival rate gradually diminished for patients with decreasing renal function. No significant differences in all-cause and cardiac mortality were observed by medical treatment, PCI or CABG, in CKD patients with an eGFR less than 60 mL/min/1.73 m(2). CKD patients with drug-eluting stents showed significantly lower all-cause mortality (5.4% vs. 13.3%) and incidence of myocardial infarction (1.7% vs. 10%) than those with bare metal stents. In conclusion, an eGFR is a strong independent prognostic marker among patients undergoing CAG and the severity of CAD increases progressively with worsening renal function.

Clinical and serologic markers of periodontal infection and chronic kidney disease

BACKGROUND

Chronic kidney disease and its concomitant sequelae represent a major public health problem. Recent data suggest periodontal infection contributes to chronic kidney disease.

METHODS

This United States population-based study of 4,053 adults > or =40 years of age investigated the association between chronic kidney disease and clinical measures and serologic markers of periodontal infection. Chronic kidney disease was defined as moderate-to-severe reduction of kidney function with glomerular filtration rate of 15 to 59 ml/minute/1.73 m(2) based on stages 3 and 4 of the Kidney Disease Outcome Quality Initiative. Chronic oral inflammatory burden was measured as 1) clinical periodontal infection categorized as no periodontal disease, periodontal disease (at least one tooth with > or =4 mm loss of attachment and bleeding on probing as an indicator of inflammation), or edentulism and 2) serum immunoglobulin G antibody response to Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) and Porphyromonas gingivalis. Multiple logistic regression modeling quantified the association between chronic kidney disease and chronic inflammatory burden and other risk factors.

RESULTS

Nine percent of the study population had chronic kidney disease, 22% had high A. actinomycetemcomitans antibody titer, 24% had high P. gingivalis antibody titer, 9% had periodontal disease, and 17% were edentulous. After simultaneously adjusting for recognized risk factors, adults with a high A. actinomycetemcomitans titer were less likely to have chronic kidney disease (adjusted odds ratio [OR(Adj)] = 0.67; 95% confidence interval [CI]: 0.46 to 0.98), and adults with edentulism were more likely to have chronic kidney disease (OR(Adj) = 1.64; 95% CI: 1.11 to 2.44).

CONCLUSION

These results support considering edentulism and low serum titer to A. actinomycetemcomitans as risk indicators for chronic kidney disease.

Cardiovascular events and all-cause mortality by albuminuria and decreased glomerular filtration rate in patients with vascular disease

OBJECTIVES

Albuminuria and decreased estimated glomerular filtration rate (eGFR) are associated with increased cardiovascular risk, but do not necessarily coexist and have different pathophysiological mechanisms. This study aims to evaluate separate and combined effects of decreased eGFR and albuminuria on the occurrence of vascular diseases and mortality in patients with vascular disease.

DESIGN

Prospective cohort study.

SETTING

University Medical Center Utrecht, the Netherlands.

SUBJECTS AND MAIN OUTCOME MEASURES

2600 patients with vascular disease were followed for vascular events, vascular and all-cause mortality. Cox regression analysis was used to calculate hazard ratios (HRs) according to eGFR (MDRD) and albuminuria (albumin-to-creatinine ratio >3 mg mmol(-1)).

RESULTS

In this population, 14.0% had albuminuria, 15.6% had eGFR <60 ml min(-1) 1.73 m(-2) and 5.2% had both. Nonalbuminuric decreased eGFR and albuminuria with normal eGFR generated moderately increased risks on all outcomes. eGFR <60 ml min(-1) 1.73 m(-2) without albuminuria mainly influenced the risk of vascular events (HR 1.50; 1.05-2.15) whilst albuminuria with eGFR >or=60 ml min(-1) 1.73 m(-2) principally affected all-cause mortality (HR 1.53; 1.04-2.26). The combination of eGFR <60 ml min(-1) 1.73 m(-2) and albuminuria was associated with an increased risk for vascular events (HR 2.27; 1.54-3.34), vascular mortality (HR 2.22; 1.40-3.52) and all-cause mortality (HR 1.84; 1.25-2.69). Comparable results were found in additional analyses amongst 759 diabetic patients.

CONCLUSIONS

The combination of decreased eGFR with albuminuria is associated with the highest risks of vascular events, vascular and all-cause mortality in patients with vascular diseases. To adequately estimate vascular risk associated with impaired renal function, both eGFR and urinary albumin should be considered.