Inflammation and Subclinical Infection in Chronic Kidney Disease: A Molecular Approach

The genetic determinants of oral diseases in Africa: The gaps should be filled

Oral diseases are a major health concern and are among the most prevalent diseases globally. This problem is becoming more prominent in the rapidly growing populations of Africa. It is well documented that Africa exhibits the most diverse genetic make-up in the world. However, little work has been conducted to understand the genetic basis of oral diseases in Africans. Oral health is often neglected and receives low prioritisation from funders and governments. The genetic determinants of highly prevalent oral diseases such as dental caries and periodontal disease, and regionally prevalent conditions such as oral cancer and NOMA, are largely under-researched areas despite numerous articles alluding to a high burden of these diseases in African populations. Therefore, this review aims to shed light on the significant gaps in research on the genetic and genomic aspects of oral diseases in African populations and highlights the urgent need for evidence-based dentistry, in tandem with the development of the dentist/scientist workforce.

Systemic Profile of Cytokines in Arteriovenous Fistula Patients and Their Associations with Maturation Failure

Background

Systemic cytokines are elevated in patients with chronic kidney disease (CKD) and on hemodialysis compared with the general population. However, whether cytokine levels interfere with vascular remodeling, increasing the risk of arteriovenous fistula (AVF) failure, remains unknown.

Methods

This is a case-control study of 64 patients who underwent surgery for AVF creation (32 with AVF maturation failure and 32 matching controls with successful maturation). A total of 74 cytokines, including chemokines, interferons, interleukins, and growth factors, were measured in preoperative plasma samples using multiplex assays. Sixty-two patients were included in the statistical analyses. Associations with AVF failure were assessed using paired comparisons and conditional logistic regressions accounting for paired strata.

Results

Seven cytokines were significantly higher in patients with AVF maturation failure than in matching controls (G-CSF, IL-6, MDC, RANTES, SDF-1α/β, TGFα, and TPO). Of these, G-CSF (odds ratio [OR]=1.71; 95% confidence interval [95% CI], 1.05 to 2.79 per 10 pg/ml), MDC (OR=1.60, 95% CI, 1.08 to 2.38 per 100 pg/ml), RANTES (OR=1.55, 95% CI, 1.10 to 2.17 per 100 pg/ml), SDF-1α/β (OR=1.18, 95% CI, 1.04 to 1.33 per 1000 pg/ml), and TGFα (OR=1.39, 95% CI 1.003, 1.92 per 1 pg/ml) showed an incremental association by logistic regression.

Conclusions

This study identified a profile of plasma cytokines associated with adverse maturation outcomes in AVFs. These findings may open the doors for future therapeutics and markers for risk stratification.

Circulating Bacterial Fragments as Cardiovascular Risk Factors in CKD

Cardiovascular disease (CVD) is a major cause of mortality and morbidity in patients with CKD. In the past decade, intestinal dysbiosis and altered gut epithelial barrier function are increasingly recognized in CKD. Uremic patients have slow intestinal transit time, impaired protein assimilation, and decreased consumption of dietary fiber. The use of multiple medications also may contribute to the proliferation of dysbiotic bacteria, which affect the barrier function of intestinal epithelium. In addition, fluid overload and uremic toxins per se directly reduce the gut barrier function. The major consequence of these alterations, the translocation of bacterial fragments from bowel lumen to systemic circulation, can lead to diverse biologic effects and probably represents an important nontraditional CVD risk factor in CKD. Among all bacterial fragments, endotoxin is the most well studied. Plasma endotoxin levels are markedly elevated in both patients with CKD and those on dialysis, and are associated with the systemic inflammatory state, accelerated atherosclerosis, and clinical CVD in patients on dialysis. Optimization of BP control and the use of ultrapure dialysate can reduce plasma endotoxin levels, with probable metabolic and cardiovascular benefits. The benefit of synbiotic therapy is not confirmed, although results from animal studies are impressive. The biologic effects and clinical relevance of other bacterial fragments, such as bacterial DNA fragments, are less well defined. Further studies are needed to delineate the pathogenic relation between circulating bacterial fragments and CVD, and to define the role of the plasma bacterial fragment level as a prognostic indicator of CKD.

Cardiovascular Risk in Hemodialysis Patients: A Mechanistic Approach

A new formula is proposed to express the excess burden of cardiovascular risk faced by hemodialysis patients as a function of various inherent, acquired and potentially modifiable factors. The proposed equation CVRHD = CVRB X f(([CKD+HD]/[HDtech+Dr])+X) includes the terms: CVRHD (cardiovascular risk in hemodialysis patients); CVRB (baseline cardiovascular risk); CKD (risk associated with chronic kidney disease); HD (risks associated with the process of hemodialysis); HDtech (benefits of new hemodialysis technologies); Dr (benefits of drug therapies) and X (unknown or putative factors influencing cardiovascular morbidity).

We review the various factors included in this proposed formula, touching upon the epidemiology, pathophysiology and therapeutic implications, including possible strategies to modify risk. As is apparent from the formula, CKD and HD in particular act as risk multipliers in augmenting or amplifying the baseline cardiovascular risk, while new hemodialysis technologies may provide an opportunity for “cardioprotective dialysis.” Drug treatment may serve to mitigate some of the risk unique to this population.

Ultrapure dialysis water obtained with additional ultrafilter may reduce inflammation in patients on hemodialysis

BACKGROUND

Patients on standard dialysis, in particular those on high-flux and high-efficiency dialysis, are exposed to hundreds of liters of dialysis-water per week. The quality of dialysis-water is a factor responsible for inflammation in dialysis patients. Inflammation is a potent trigger of atherosclerosis and a pathogenetic factor in anemia, increasing mortality and morbidity in dialysis patients. Current systems for water treatment do not completely eliminate bacteria and endotoxins. This prospective study tested whether improved dialysis-water purity by an additional ultrafilter can reduce inflammation and ameliorate hemoglobin levels, with a consequent reduction in erythropoietin-stimulating agents (ESA).

METHODS

An ultrafilter, composed of two serially positioned devices with polysulfone membranes of 2.0 and 1.0 m2, respectively, was positioned within the fluid pathway before the dialysis machine. Prevalent dialysis patients were assigned either to continue dialysis with conventional dialysis-water (control phase) or to initiate dialysis sessions with improved dialysis-water purity (study phase). After 6 months, patients were crossed over. Total study duration was 1 year. Routine chemistry, bacterial count, endotoxin levels in dialysis-water as well as blood levels of pro- and anti-inflammatory cytokines, human serum amyloid A, C-reactive protein and fraction 5 of complement were measured.

RESULTS

Thirty-two patients completed the study. Mean bacterial count was lower and endotoxin levels were absent in dialysis-water obtained with the ultrafilter. At the end of the study-phase, C-reactive protein and pro-inflammatory cytokines decreased while anti-inflammatory ones increased. Hemoglobin levels were improved with lower ESA doses.

CONCLUSIONS

An additional ultrafilter improved dialysis-water purity, reduced levels of inflammation markers, ameliorated hemoglobin concentration with reduced ESA doses. These results remain speculative but they may generate studies to assess whether improved dialysis-water quality with an ultrafilter can reduce inflammation and improve survival of dialysis patients.

Indication for Dialysis Initiation and Mortality in Patients With Chronic Kidney Failure: A Retrospective Cohort Study

BACKGROUND

Initiation of maintenance dialysis therapy for patients with chronic kidney failure is a period of high risk for adverse patient outcomes. Whether indications for dialysis therapy initiation are associated with mortality in this population is unknown.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

461 patients who initiated dialysis therapy (hemodialysis, 437; peritoneal dialysis, 24) from January 1, 2004, through December 31, 2012, and were treated in facilities operated by a single dialysis organization. Follow-up for the primary outcome was through December 31, 2013.

PREDICTOR

Clinically documented primary indication for dialysis therapy initiation, as categorized into 4 groups: laboratory evidence of kidney function decline (reference category), uremic symptoms, volume overload or hypertension, and other/unknown.

OUTCOMES

All-cause mortality.

RESULTS

During a median follow-up of 2.4 years, 183 (40%) patients died. Crude mortality rates were 10.0 (95% CI, 6.8-14.7), 12.7 (95% CI, 10.2-15.7), 21.7 (95% CI, 16.4-28.6), and 12.2 (95% CI, 6.8-14.7) deaths/100 patient-years among patients initiating dialysis therapy primarily for laboratory evidence of kidney function decline, uremic symptoms, volume overload or hypertension, and other/unknown reason, respectively. Following adjustment for demographic variables, coexisting illnesses, and estimated glomerular filtration rate, initiation of dialysis therapy for uremic symptoms, volume overload or hypertension, or other/unknown reasons was associated with 1.12 (95% CI, 0.72-1.77), 1.69 (95% CI, 1.02-2.80), and 1.28 (95% CI, 0.73-2.26) times higher risk, respectively, for subsequent mortality compared to initiation for laboratory evidence of kidney function decline.

LIMITATIONS

Possibility of residual confounding by unmeasured variables; reliance on clinical documentation to ascertain exposure.

CONCLUSIONS

Patients initiating dialysis therapy due to volume overload may have increased risk for mortality compared with patients initiating dialysis due to laboratory evidence of kidney function decline. Further studies are needed to identify and test interventions that might reduce this risk.

Relationships between plasma pentraxin 3 levels and inflammation markers patients with tunneled permanent catheter in hemodialysis

PURPOSE

Vascular access (VA) devices may contribute to chronic inflammation in hemodialysis (HD). Pentraxin 3 (PTX3) is a recently discovered acute phase protein that responds more rapidly than other inflammatory markers. This study compared PTX3 and other markers between HD patients and healthy controls.

METHODS

The study population included 30 patients with tunneled permanent catheter (TPC), 30 patients with arteriovenous fistula (AVF) and 30 healthy controls. Hemogram, biochemical assays, ferritin, high sensitive C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α) and PTX3 were evaluated in all groups.

RESULTS

PTX levels were highest in HD patients with TPC, intermediated in HD patients with AVF and lowest in healthy controls (5.2 + 2.4 vs. 3.1 + 1.3 vs. 1.8 + 0.7, p<0.001 for all comparisons). PTX3 levels correlated strongly to hs-CRP (r = 0.857) and moderately to TNF-α, NLR, ferritin and total neutrophil count. PTX3 and albumin levels had a negative correlation. PTX3 levels were higher in patients with 8 months of TPC than those with 7 months or less.

CONCLUSIONS

PTX3 levels are significantly elevated in all patients on HD, but presence and extended duration of TPC are associated with incrementally higher levels of PTX3 and other inflammatory markers. PTX3 and NLR may be useful in assessing chronic inflammatory states in HD.

Microbiology and epidemiology of Halomonas species

Halomonas has been organized as a genus since 1980, and comprises halophilic and/or halotolerant Gram-negative aerobic bacteria, typically found in saline environments. The genus is enlarging: at present, 76 species are taxonomically recognized, with more to be added. Increasing industrial uses have been found, largely in bioremediation and the production of desirable compounds. Originally seen as environmental contaminants, pathogenicity was initially not recognized; however, disease in algae, animals and humans has now been described. As the biotechnological use of these species increases, and the ability to isolate and recognize them improves, one might expect further pathogenic encounters with humans to be described.

Halomonas johnsoniae: review of a medically underappreciated genus of growing human importance

The growing genus Halomonas includes bacteria favoring or tolerating high-saline/halide and high-pH environments. Infections are rarely reported. A patient developed Halomonas johnsoniae (previously reported only as dialysis unit environmental contaminants) bacteremia. The medical community is alerted to the pathogenic potential of the genus, particularly in a dialysis setting.

Periodontitis and chronic kidney disease: a systematic review of the association of diseases and the effect of periodontal treatment on estimated glomerular filtration rate

AIM

The aim of this systematic review (SR) was to evaluate the association between periodontitis and chronic kidney disease (CKD) and the effect of periodontal treatment (PT) on the estimated glomerular filtration rate (eGFR).

METHODS

MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched up to and including September 30, 2012 to observational (S1) and interventional (S2) studies on the association of periodontitis with CKD. Studies were considered eligible for inclusion if they reported the eGFR. Search was conducted by two independent reviewers. The methodological quality of the observational studies was assessed using the Newcastle-Ottawa Scale (NOS) adapted for this review, and the Cochrane's Collaboration risk of bias assessment tool. A random-effects odds-ratio meta-analysis was conducted to estimate the degree of association between periodontitis and CKD.

RESULTS

Search strategy identified 2456 potentially eligible articles, of which four cross-sectional, one retrospective, and three interventional studies were included. Four S1, 80.0% reported some degree of association between periodontitis and CKD. Similarly, such an outcome was supported by pooled estimates (OR: 1.65, 95% Confidence Interval: 1.35, 2.01, p < 0.00001, χ(2)  = 1.70, I(2 ) = 0%). All interventional studies found positive outcomes related to treatment.

CONCLUSION

There is quite consistent evidence to support the positive association between periodontitis and CKD, as well as the positive effect of PT on eGFR.

Pentraxins in nephrology: C-reactive protein, serum amyloid P and pentraxin-3

Every clinician uses C-reactive protein (CRP) levels as a biomarker for systemic inflammation in acute disorders. Nephrologists also consider CRP levels as a predictor for overall mortality in patients with chronic kidney disease or end-stage renal disease. But what is the biological function of CRP? CRP is a member of the family of pentraxins, which are small pentameric innate immunity effector proteins. Pentraxins are absent or weakly expressed during homeostasis. However, the pro-inflammatory cytokines interleukin (IL)-1, IL-6 and tumour necrosis factor induce CRP and serum amyloid P (SAP) in hepatocytes, whereas the long pentraxins, such as pentraxin (PTX)-3, are produced in peripheral tissues and monocytic phagocytes. Pentraxins opsonize pathogens or other particles such as dead cells, for their phagocytic clearance or induce pathogen killing in extracellular compartments. In this review, we discuss the immunoregulatory properties of the different members of the pentraxin family. We discuss the evolving evidence demonstrating their roles in acute and chronic forms of kidney disease and the significance of SAP and PTX3 as additional biomarkers of innate immune activation and systemic inflammation.

Screening for bacteremia in sepsis and renal failure using hemofilters for renal replacement therapy

BACKGROUND

In patients with sepsis and renal failure, extracorporeal blood flow during renal replacement therapy may lead to the deposition of bacteria on artificial membranous surfaces, which might be suitable for the detection of pathogens. We studied whether discarded dialysis hemofilters can be used for the detection of bacteremia in patients with sepsis and renal failure.

METHODS

Hemofilters of 16 ICU patients with sepsis were sampled. The hemofilters were incubated with soy broth and dehisced under sterile conditions. Samples were plated on blood agar and analyzed. Patient's characteristics were assessed.

RESULTS

Despite the use of antibiotics in 87.5 % (14/16), a true positive detection rate of 31.3 % (5/16) for bacteremia was found by using cultures from hemofilters. The overall true positive rate of blood cultures was significantly lower (10.7 %, 8/75, p = 0.048). Bacteria detected in hemofilters were similar to those found in blood cultures or by cultures from other sources of infection in 80 % (4/5).

CONCLUSIONS

Cultures from used hemofilters of patients with sepsis and renal failure provide the opportunity to identify pathogenic microorganisms as an add-on approach. Further studies should investigate whether this method is applicable in clinical practice to enhance the sensitivity of microbiological diagnostics.

DNA hypermethylation and inflammatory markers in incident Japanese dialysis patients

Background/Aims

Inflammation is an established mortality risk factor in chronic kidney disease (CKD) patients. Although a previous report showed that uremic Caucasian patients with inflammation had signs of global DNA hypermethylation, it is still unknown whether DNA hypermethylation is linked to inflammatory markers including a marker of bacterial infections in Japanese CKD patients.

Methods

In 44 consecutive incident dialysis patients (26 males, mean age 59 ± 12 years) without clinical signs of infection, global DNA methylation was evaluated in peripheral blood DNA using the HpaII/MspI ratio by the luminometric methylation assay method. A lower ratio of HpaII/MspI indicates global DNA hypermethylation. Procalcitonin (PCT), a marker of inflammation due to bacterial infections, was measured using an immunochromatographic assay.

Results

The patients were divided into hyper- and hypomethylation groups based on the median value of the HpaII/MspI ratio 0.31 (range 0.29–0.37). Whereas patients in the hypermethylation group had higher ferritin levels [133.0 (51.5–247.3) vs. 59.5 (40.0–119.0) ng/ml; p = 0.046], there were no significant differences in age, gender, diabetes, smoking, anemia or serum albumin levels. However, the HpaII/MspI ratio showed significant negative correlations with PCT (ρ = −0.32, p = 0.035) and ferritin (ρ = −0.33, p = 0.027) in Spearman's rank test. In a multiple linear regression analysis, PCT and ferritin were associated with a lower HpaII/MspI ratio (R² = 0.24, p = 0.013).

Conclusion

In this study, global DNA hypermethylation was associated with ferritin and, most likely, PCT, suggesting that inflammation induced by subclinical bacterial infection promoted DNA methylation.

Urinary tract infections caused by staphylococcus aureus DNA in comparison to the candida albicans DNA

Background:

Bacterial DNA released upon bacterial autolysis or killed by antibiotics, hence, many inflammatogenic reactions will be established leading to serious tissue damage.

Aim:

the present work aimed to elucidate the histopathological changes caused by prokaryotic (bacterial) DNA and eukaryotic (candidal) DNA.

Materials and Methods:

twenty one Staphylococcus aureus and 36 Candida albicans isolates were isolated from UTI patients. Viable cells and DNA of the highest antibiotic sensitive isolates were injected, intraurethraly, in mice. Results were evaluated via histopathological examination.

Results:

Mildest reactions were obtained from mice challenged with viable C. albicans compared with those challenged with viable S. aureus. Dose-dependent histological changes were observed for both eukaryotic and prokaryotic DNA. However, the eukaryotic C. albicans DNA developed less intense histological changes than S. aureus DNA.

Conclusion:

microbial DNA has the ability to cause damage in murine renal system. Nevertheless, bacterial DNA caused more intense damage than candidal DNA.

Risk factors for chronic kidney diseases may include periodontal diseases, as estimated by the correlations of plasma pentraxin-3 levels: a case-control study

BACKGROUND

Pentraxins are classical mediators of inflammation and markers of acute-phase reactions. Pentraxin-3 (PTX3) is believed to be a true independent indicator of disease activity. It has been associated with clinical outcomes in incident chronic kidney disease (CKD) and periodontal diseases. Periodontitis is lately being considered as a risk factor for CKD. However, no data are available on elevated PTX3 in patients with CKD associated with periodontitis.

METHOD

Sixty subjects were divided into three groups (n = 20) based on glomerular filtration rate (GFR) and periodontal parameters: healthy (group-1), CKD (group-2), and CKD with periodontitis (group-3). Plasma samples obtained from each patient were quantified for PTX3 using Enzyme-linked Immunosorbent Assay (ELISA).

RESULTS

Both patient groups with CKD had higher plasma PTX3 concentrations than control subjects. However, there was no significant difference between the two groups (groups 2 and 3). In all groups, plasma PTX3 correlated positively with periodontal parameters. Group 3 patients had higher concentrations of PTX3 (6.338 ng/ml) than group 2 (5.41 ng/ml) and group 1 (1.835 ng/ml).

CONCLUSIONS

Within the limits of the present study, the difference in plasma PTX3 levels between groups 2 and 3 was not found to be statistically significant (P > 0.05). However, as PTX3 values correlated positively with periodontal parameters, this model could contribute to identifying individuals with periodontitis at high risk of CKD. Thus, periodontal disease could serve as a risk factor for developing CKD. Further large-scale studies nullifying the confounders for CKD are warranted to confirm positive results.

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.

Halomonas, a newly recognized human pathogen causing infections and contamination in a dialysis center: three new species

Our Renal Care Center (RCC) is a separate building, performing almost 2500 outpatient dialysis runs per month. In May 2007, 2 patients developed, days apart, bacteremia with an apparently identical nonfermentative Gram-negative rod. Because of difficulty identifying the organism, testing in the Biolog system identified them as a Halomonas species. Sequencing of approximately 1500 bases of the 16S rRNA gene in both organisms in 3 reference laboratories confirmed, searching against 3 databases, that the organisms were identical and were Halomonas species. There were 54 recognized species of this genus, associated with marine or saline sites. Initial attempts at environmental isolation as primary cultures, including a 4% salt agar plate, or initial incubation in 6.5% salt broth enrichment culture with subculture to agar, to exploit the halophilicity of Halomonas, were successful in demonstrating the colonies seen in the blood cultures, only from sites not contaminated with other organisms, because of competing growth. A more selective method was developed for use on samples suspected to be heavily contaminated with other organisms, using the strategy of increased salt concentration in a broth enrichment culture to further exploit Halomonas halotolerance, and thereby inhibit other organisms. A 16.5% salt concentration in brain-heart infusion broth, incubated at 35 degrees C for 48-72 hours, then subcultured to agar plates incubated in room air at 35 degrees C, proved optimal for selection and secondary isolation. With a combination of these techniques, 14/15 cultures of dialysates and 10/38 from the outflow pathways of the machines were Halomonas positive, compared to 0/31 cultures from the inflow side of the machines (including water supplies and storing, mixing, and preparation tanks). The exception was sites associated with or downstream of bicarbonate influx, 12/54 of which were positive. Two other local hospitals' dialysis centers, and our own inpatient dialysis facility, were cultured at sites that yielded Halomonas from our RCC, and Halomonas was not isolated. Further study by 16S rRNA gene sequencing and DNA-DNA hybridization revealed the cultures represented 3 novel species: 1 (H. stevensii sp. nov.) in the patients and environment and 2 (H. hamiltonii sp. nov., H. johnsoniae sp. nov.) in the environment, most closely related to H. magadiensis. Of 35 speciated isolates, 22 were H. stevensii, 10 H. johnsoniae, and 3 H. hamiltonii. We hypothesize that the RCC became contaminated with these halophilic organisms from bicarbonate used to prepare dialysis fluid, and they persist despite cleaning and flushing procedures because of biofilm in machines and bicarbonate fluid inflow sites. Our experience, together with the review of the literature presented here, indicates the genus Halomonas has pathogenic potential.

Circulating bacterial-derived DNA fragments and markers of inflammation in chronic hemodialysis patients

BACKGROUND AND OBJECTIVES

Bacterial-derived DNA fragments (BDNAs) have been shown to be present in dialysis fluid, to pass through dialyzer membranes, and to induce IL-6 (IL-6) in mononuclear cells. The present study aimed at assessing the eventual presence of BDNAs in the blood of hemodialysis (HD) patients and if this is associated with markers of chronic inflammation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Fifty-eight HD patients and 30 controls were included in the study. A blood sample was collected from a peripheral vein and from the central venous catheter (CVC) or the arteriovenous fistula (AVF) and examined for presence of BDNAs by 16S rRNA gene PCR amplification, bacterial growth, and measurement of C-reactive protein and IL-6. Thirty minutes after the start of HD, a sample of dialysis fluid was collected before the entry into and at the exit of the dialyzer and examined for presence of BDNAs.

RESULTS

Controls had negative blood cultures and absence of blood BDNAs. All HD patients had negative blood cultures, but in 12 (20.7%), BDNAs were present in the whole blood. In five of the latter, BDNAs were also found in the dialysis fluid. C-reactive protein serum levels (mg/L) were significantly higher in patients with than in those without BDNAs. Likewise, IL-6 serum levels (pg/ml) were significantly higher in patients with BDNA than in those without.

CONCLUSIONS

Circulating BDNAs are associated with higher levels of C-reactive protein and IL-6 in HD patients.

Cardiorenal syndrome

The term cardiorenal syndrome (CRS) increasingly has been used without a consistent or well-accepted definition. To include the vast array of interrelated derangements, and to stress the bidirectional nature of heart-kidney interactions, we present a new classification of the CRS with 5 subtypes that reflect the pathophysiology, the time-frame, and the nature of concomitant cardiac and renal dysfunction. CRS can be generally defined as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic dysfunction of 1 organ may induce acute or chronic dysfunction of the other. Type 1 CRS reflects an abrupt worsening of cardiac function (e.g., acute cardiogenic shock or decompensated congestive heart failure) leading to acute kidney injury. Type 2 CRS comprises chronic abnormalities in cardiac function (e.g., chronic congestive heart failure) causing progressive chronic kidney disease. Type 3 CRS consists of an abrupt worsening of renal function (e.g., acute kidney ischemia or glomerulonephritis) causing acute cardiac dysfunction (e.g., heart failure, arrhythmia, ischemia). Type 4 CRS describes a state of chronic kidney disease (e.g., chronic glomerular disease) contributing to decreased cardiac function, cardiac hypertrophy, and/or increased risk of adverse cardiovascular events. Type 5 CRS reflects a systemic condition (e.g., sepsis) causing both cardiac and renal dysfunction. Biomarkers can contribute to an early diagnosis of CRS and to a timely therapeutic intervention. The use of this classification can help physicians characterize groups of patients, provides the rationale for specific management strategies, and allows the design of future clinical trials with more accurate selection and stratification of the population under investigation.

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.

Immune dysfunction in uremia

Kidney dysfunction leads to disturbed renal metabolic activities and to impaired glomerular filtration, resulting in the retention of toxic solutes affecting all organs of the body. Cardiovascular disease (CVD) and infections are the main causes for the increased occurrence of morbidity and mortality among patients with chronic kidney disease (CKD). Both complications are directly or indirectly linked to a compromised immune defense. The specific coordinated roles of polymorphonuclear leukocytes (PMNLs), monocytes/macrophages, lymphocytes and antigen-presenting cells (APCs) in maintaining an efficient immune response are affected. Their normal response can be impaired, giving rise to infectious diseases or pre-activated/primed, leading to inflammation and consequently to CVD. Whereas the coordinated removal via apoptosis of activated immune cells is crucial for the resolution of inflammation, inappropriately high apoptotic rates lead to a diminished immune response. In uremia, the balance between pro- and anti-inflammatory and between pro- and anti-apoptotic factors is disturbed. This review summarizes the interrelated parameters interfering with the immune response in uremia, with a special focus on the non-specific immune response and the role of uremic toxins.