Long Pentraxin 3 as a Broader Biomarker for Multiple Risk Factors in End-Stage Renal Disease: Association with All-Cause Mortality

Biomarkers of chronic kidney disease in older individuals: navigating complexity in diagnosis

Chronic kidney disease (CKD) in older individuals is a matter of growing concern in the field of public health across the globe. Indeed, prevalence of kidney function impairment increases with advancing age and is often exacerbated by age-induced modifications of kidney function, presence of chronic diseases such as diabetes, hypertension, and cardiovascular disorders, and increased burden related to frailty, cognitive impairment and sarcopenia. Accurate assessment of CKD in older individuals is crucial for timely intervention and management and relies heavily on biomarkers for disease diagnosis and monitoring. However, the interpretation of these biomarkers in older patients may be complex due to interplays between CKD, aging, chronic diseases and geriatric syndromes. Biomarkers such as serum creatinine, estimated glomerular filtration rate (eGFR), and albuminuria can be significantly altered by systemic inflammation, metabolic changes, and medication use commonly seen in this population. To overcome the limitations of traditional biomarkers, several innovative proteins have been investigated as potential, in this review we aimed at consolidating the existing data concerning the geriatric aspects of CKD, describing the challenges and considerations in using traditional and innovative biomarkers to assess CKD in older patients, highlighting the need for integration of the clinical context to improve biomarkers' accuracy.

Impact of TNFRSF1B (rs3397, rs1061624 and rs1061622) and IL6 (rs1800796, rs1800797 and rs1554606) Gene Polymorphisms on Inflammatory Response in Patients with End-Stage Kidney Disease Undergoing Dialysis

We aimed to study the impact of polymorphisms in the genes encoding interleukin-6 (IL6) and tumor necrosis factor receptor-2 (TNFR2), reported to be mortality risk predictors, in patients with end-stage kidney disease (ESKD) undergoing dialysis. TNFRSF1B (rs3397, rs1061624, and rs1061622) and IL6 (rs1800796, rs1800797, and rs1554606) polymorphisms were studied in patients with ESKD and controls; the genotype and allele frequencies and the associations with inflammatory and erythropoiesis markers were determined; deaths were recorded throughout the following two years. The genotype and allele frequencies for the TNFRSF1B rs3397 polymorphism were different in these patients compared to those in the controls and the global and European populations, and patients with the C allele were less common. Patients with the CC genotype for TNFRSF1B rs3397 presented higher hemoglobin and erythrocyte counts and lower TNF-α levels, suggesting a more favorable inflammatory response that seems to be associated with erythropoiesis improvement. Patients with the GG genotype for TNFRSF1B rs1061622 showed lower serum ferritin levels. None of the TNFRSF1B (rs3397, rs1061624, and rs1061622) or IL6 (rs1800796, rs1800797, and rs1554606) polymorphisms had a significant impact on the all-cause mortality rate of Portuguese patients with ESKD.

Pentraxin-3 and Outcomes in CKD: A Systematic Review and Meta-analysis

Rationale & Objective

Long pentraxin-3 (PTX-3) serves as a biomarker for prognosticating adverse clinical outcomes in individuals with chronic kidney disease (CKD). The objective of the current meta-analysis was to evaluate the prognostic efficacy of PTX-3 in patients with CKD. In addition, we compared the prognostic effectiveness of PTX-3 and the short pentraxin C-reactive protein (CRP) in the identical cohort of patients with CKD.

Study Design

A systematic review and meta-analysis.

Setting & Participants

Patients with CKD treated with or without dialysis.

Selection Criteria for Studies

A cohort study with a minimum 1-year follow-up.

Data Extraction

Risk measurements, adjusted hazard risk with 95% CI, and modified variables.

Analytical Approach

To aggregate the adjusted effect estimates, a fixed-effects or random-effects model was employed.

Results

Nine studies covering 1,825 patients with CKD were selected in the present review. Six of the 9 studies exclusively included patients receiving hemodialysis. The collected findings indicated that patients with CKD in the highest tertile of PTX-3 demonstrated significantly higher risks of all-cause mortality (HR, 1.92; 95% CI, 1.44-2.56), cardiovascular death (HR, 1.98; 95% CI, 1.28-3.05), infectious death (HR, 5.26; 95% CI, 1.60-17.31), and fatal and nonfatal cardiovascular events (HR, 1.81; 95% CI, 1.35-2.42), as compared with those in the lowest tertile. These significant associations with risk were also observed when effect estimates were presented as per unit change in the PTX-3. Moreover, when comparing the prognostic value of PTX-3 and CRP in the same individuals (5 studies covering 904 patients), PTX-3 proved to be a satisfactory predictor of adverse events in these patients, whereas CRP failed to exhibit such predictive capability, regardless of the type of effect estimate used.

Limitations

A relatively small sample size and some heterogeneity.

Conclusions

Pentraxin 3 is associated with adverse events in individuals with CKD and may be a more reliable predictor of adverse clinical events than CRP in this population.

Nonlinear associations between computed tomography-measures of adiposity and long pentraxin-3 in the Multi-Ethnic Study of Atherosclerosis

Objective

Long pentraxin-3 (PTX-3) is an acute phase protein associated with cardiovascular disease, lung injury, and mortality. We evaluated the association between computed tomography (CT)-measurements of adipose tissue and plasma levels of PTX-3.

Methods

We performed a cross-sectional analysis of community-dwelling adults enrolled in the multi-center Multiethnic Study of Atherosclerosis who underwent cardiac or abdominal CT and had available PTX-3 measurements.

Results

There was a U-shaped association between pericardial adipose tissue volume (PAT), abdominal visceral adipose tissue area (VAT), hepatic attenuation, and PTX-3 levels, with extremes of adiposity associated with greater PTX-3 levels. Using multivariable-adjusted piecewise regression models, among participants with low PAT, every 1% increase in PAT volume was associated with a 13.8% decrease in PTX-3 (95% confidence interval [CI] -21.6 to -6.0); among participants with high PAT, every 1% increase in PAT volume was associated with a 6.0% increase in PTX-3 (95% CI -0.4 to 12.5). Results were similar for abdominal VAT and hepatic attenuation.

Conclusions

In a cohort of community-dwelling adults, we demonstrated a "U-shaped" association between pericardial, abdominal visceral, and hepatic adiposity with PTX3 levels, suggesting that extreme adiposity is associated with greater circulating levels of PTX3. Further work is required to identify the mechanisms linking adiposity and PTX-3.

Animal protein intake is directly associated with serum level of pentraxin 3 in hemodialysis patients

Inflammation plays an important role in Cardiovascular disease (CVD) pathogenesis as the main cause of mortality in hemodialysis (HD) patients. Despite the relevance of nutrition and dietary intakes for inflammation status, the role of dietary protein sources remains unclear. The aim of this study was to evaluate the association between the different types of dietary protein and pentraxin 3 (PTX3) levels in HD patients. In this multi-center cross-sectional study, 227 adult patients undergoing HD for a minimum 90 days were recruited. A validated 168-item food frequency questionnaire was used to assess dietary intakes. Also, 5 ml blood samples were collected from each patient to measure the concentration of serum PTX3. Overall, 227 patients, including 63 women and 164 men, with a mean age of 58 years, participated in this study. There was a greater intake of animal protein per kilogram dry weight among patients with higher levels of PTX3 (0.46 vs. 0.54 g/kg; P = 0.035). In contrast, consumption of total protein and plant protein per kilogram dry weight was not different across PTX3 levels. Moreover, the chance of increased PTX3 concentration was directly associated with a one-unit increase in animal protein intake per kilogram dry weight, after adjusting for confounders. We did not observe any association between one-unit increases in plant protein intake per kilogram dry weight and chance of increased PTX3. In conclusion, animal protein intake was directly associated with circulating PTX3.

Pentraxin 3 plays a key role in tubular cell senescence and renal fibrosis through inducing β-catenin signaling

Renal fibrosis is the common pathological feature of various chronic kidney diseases (CKD). Tubular cell senescence plays a key role in the progression of renal fibrosis. However, the underlying mechanisms are still in mystery. In this study, we identified, Pentraxin 3 (PTX3), belonging to the Pentraxin family, is a new fibrogenic factor. PTX3 was increased in various CKD models. PTX3 was primarily localized in tubular epithelial cells and upregulated, accompanied by mitochondrial dysfunction and cellular senescence. Overexpression of PTX3 aggravated mitochondrial damage and accelerated cell senescence in tubular cells, leading to more severe fibrogenesis in kidneys. However, knockout of PTX3 significantly preserved mitochondrial homeostasis, and blocked cellular senescence in primary cultured tubular cells. Furthermore, KYA1797K, a destabilizer of β-catenin, greatly inhibited PTX3-induced mitochondrial homeostasis, tubular cell senescence, and renal fibrosis. Overexpression of PTX3 triggered nuclear translocation of β-catenin, an activating form of β-catenin. PTX3-induced mitochondrial dysfunction and tubular cell senescence were also significantly inhibited by knockdown of p16^INK4A, a senescence-related protein. In a clinical cohort, we found PTX3 was increased in urine and serum in clinical patients with CKD. Urinary PTX3 negatively correlated with the decline of eGFR. PTX3 also increased gradually following the severity of diseases, triggering the fibrogenesis. Taken together, our results provide strong evidences that PTX3 is a new fibrogenic factor in the development of renal fibrosis through β-catenin-induced mitochondrial dysfunction and cell senescence. This study further suggests PTX3 is a new diagnostic factor to renal fibrosis and provides a new therapeutic target against renal fibrosis.

Pentraxin 3 mediates early inflammatory response and EMT process in human tubule epithelial cells induced by PM2.5

Pentraxin 3 (PTX3) is a multifunctional molecule that mainly expressed in response to proinflammatory stimuli under physiological and pathological conditions. It is produced in tubule epithelial cells that is involved in the innate immune response and inflammatory reactions in the kidney. However, its role in fine particulate matter (PM2.5)-induced renal injury associated with inflammation remains to be investigated. As a result of PM2.5 exposure, the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α levels were increased in HK-2 cells. Notably, the mesenchymal phenotypes with migratory abilities of HK-2 cells were found following PM2.5 exposure. The elevated expressions of PTX3 mRNA and protein in response to PM2.5 were tested by RT-PCR and Western blotting respectively. Further determinate the role of PTX3 by siRNA showed lack of PTX3 could increase IL-6 production and promote epithelial-mesenchymal transition (EMT) process, as evidenced by decreased expressions of E-cadherin, and increased expressions of N-cadherin and α-SMA in HK-2 cells following PM2.5 exposure. Our study indicates that PTX3 mediates early inflammatory response and EMT in PM2.5-exposed HK-2 cells, suggesting a counter-regulatory role of PTX3 in the early course of tubule cell injury induced by PM2.5.

Inflammatory biomarkers in staging of chronic kidney disease: elevated TNFR2 levels accompanies renal function decline

BACKGROUND

Inflammation is a common feature in the pathogenesis of chronic kidney disease (CKD), regardless of the disease cause. Our aim was to evaluate the potential of several inflammatory biomarkers in CKD diagnosis and staging.

METHODS

A total of 24 healthy controls and 92 pre-dialysis CKD patients with diverse etiologies, were enrolled in this study and grouped according to their CKD stage. We analysed the circulating levels of inflammatory molecules, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 2 (TNFR2), pentraxin 3 (PTX3) and leptin, as well as the hemogram. We studied their association with parameters of kidney function and kidney injury, to evaluate their potential as early markers of the disease and/or of its worsening, as well as their interplay.

RESULTS

Compared to controls, patients in CKD stages 1-2 presented significantly higher IL-6 and TNFR2 levels, and higher neutrophil-to-lymphocyte ratio. All inflammatory cytokines and acute-phase proteins showed a trend to increase up to stage 3, stabilizing or declining thereafter, save for TNFR2, which steadily increased from stage to stage. All inflammatory molecules, apart from PTX3, were negatively and significantly correlated with eGFR, with a remarkable value for TNFR2 (r = - 0.732, p < 0.001).

CONCLUSION

TNFR2 might be useful for an early detection of CKD, as well as for disease staging/worsening. Still, the potential value of this biomarker in disease progression warrants further investigation.

The Signaling Pathway of TNF Receptors: Linking Animal Models of Renal Disease to Human CKD

Chronic kidney disease (CKD) has been recognized as a global public health problem. Despite the current advances in medicine, CKD-associated morbidity and mortality remain unacceptably high. Several studies have highlighted the contribution of inflammation and inflammatory mediators to the development and/or progression of CKD, such as tumor necrosis factor (TNF)-related biomarkers. The inflammation pathway driven by TNF-α, through TNF receptors 1 (TNFR1) and 2 (TNFR2), involves important mediators in the pathogenesis of CKD. Circulating levels of TNFRs were associated with changes in other biomarkers of kidney function and injury, and were described as predictors of disease progression, cardiovascular morbidity, and mortality in several cohorts of patients. Experimental studies describe the possible downstream signaling pathways induced upon TNFR activation and the resulting biological responses. This review will focus on the available data on TNFR1 and TNFR2, and illustrates their contributions to the pathophysiology of kidney diseases, their cellular and molecular roles, as well as their potential as CKD biomarkers. The emerging evidence shows that TNF receptors could act as biomarkers of renal damage and as mediators of the disease. Furthermore, it has been suggested that these biomarkers could significantly improve the discrimination of clinical CKD prognostic models.

Interleukin 6 (rs1800795) and pentraxin 3 (rs2305619) polymorphisms-association with inflammation and all-cause mortality in end-stage-renal disease patients on dialysis

Chronic inflammation plays an important role in the progression and outcome of chronic kidney disease (CKD). The circulating levels of the inflammatory biomarkers interleukin 6 (IL6) and pentraxin 3 (PTX3) are enhanced in CKD patients, and are associated with the progression of the disease and with higher risk for cardiovascular events, the major cause of death in CKD patients. Our aim was to study how specific polymorphisms of IL6 and PTX3 encoding genes affect the inflammatory response and outcome of end-stage renal disease (ESRD) patients on dialysis. Methodology included the analysis of two single nucleotide polymorphisms (SNP), namely the IL6 (rs1800795) polymorphism in the promoter region (-174G > C), and the PTX3 (rs2305619) polymorphism in the intron 1 (+ 281A > G), which were analyzed in ESRD patients on dialysis and in a group of heathy individuals. The allelic frequencies, genotype distribution and their association with circulating levels of the inflammatory markers C-reactive protein (CRP), IL6, growth differentiation factor 15 (GDF15) and PTX3, were determined in ESRD patients. Events of death were recorded along one year, to assess the association of the studied SNPs with all-cause mortality and the inflammatory biomarkers, in ESRD patients. Results showed that the allelic frequencies and genotype distribution for IL6 and PTX3 SNPs in the control group and ESRD patients were similar and in agreement with other European reports. For the IL6 polymorphism, we found a trend towards higher levels of high-sensitivity (hs) CRP, IL6 and PTX3 in the homozygous genotypes; the CC genotype also showed the highest levels of GDF15. The mortality rate after the 1-year follow-up was 10.4%. The CC genotype (IL6 SNP) was associated to a higher risk of mortality and deceased patients carrying this genotype also showed the highest levels of hsCRP. Regarding the studied PTX3 SNP, the AA genotype was linked to an enhanced inflammatory response, showing the highest values of hsCRP and IL6. Nevertheless, this genotype had no significant impact on the mortality rate. In conclusion, both studied SNPs seem to modulate the inflammatory response in ESRD and may, therefore, be determinant on disease progression and patients' outcome. Our data also highlights the importance of research on genetic variants that, although less frequent, may have significant biological value.

Periodontitis Exacerbates and Promotes the Progression of Chronic Kidney Disease Through Oral Flora, Cytokines, and Oxidative Stress

Periodontitis is a type of systemic immune inflammation that is caused by the complex infection of a variety of microorganisms in the subgingival plaque and the imbalance of the microbial ecological environment in the mouth. Periodontitis and chronic kidney disease (CKD) share many risk factors, such as obesity, smoking, and age. A growing body of data supports a strong correlation between periodontitis and kidney disease. Evidence supports the role of periodontal inflammation and elevated serum inflammatory mediators in renal atherosclerosis, renal deterioration, and end-stage renal disease (ESRD) development. Periodontitis is a risk factor for kidney disease. However, to our knowledge, there are few studies detailing the possible link between periodontitis and CKD. This review summarizes the possible mechanisms underlying periodontitis and CKD. More importantly, it highlights novel and potential pathogenic factors for CKD, including bacteria, pro-inflammatory mediators and oxidative stress. However, most research on the relationship between periodontitis and systemic disease has not determined causality, and these diseases are largely linked by bidirectional associations. Future research will focus on exploring these links to contribute to new treatments for CKD.

New Potential Biomarkers for Chronic Kidney Disease Management-A Review of the Literature

The prevalence of chronic kidney disease (CKD) is increasing worldwide, and the mortality rate continues to be unacceptably high. The biomarkers currently used in clinical practice are considered relevant when there is already significant renal impairment compromising the early use of potentially successful therapeutic interventions. More sensitive and specific biomarkers to detect CKD earlier on and improve patients' prognoses are an important unmet medical need. The aim of this review is to summarize the recent literature on new promising early CKD biomarkers of renal function, tubular lesions, endothelial dysfunction and inflammation, and on the auspicious findings from metabolomic studies in this field. Most of the studied biomarkers require further validation in large studies and in a broad range of populations in order to be implemented into routine CKD management. A panel of biomarkers, including earlier biomarkers of renal damage, seems to be a reasonable approach to be applied in clinical practice to allow earlier diagnosis and better disease characterization based on the underlying etiologic process.

Cell-free DNA as a marker for the outcome of end-stage renal disease patients on haemodialysis

Background

DNA damage and inflammation are common in end-stage renal disease (ESRD). Our aim was to evaluate the levels of circulating cell-free DNA (cfDNA) and the relationship with inflammation, anaemia, oxidative stress and haemostatic disturbances in ESRD patients on dialysis. By performing a 1-year follow-up study, we also aimed to evaluate the predictive value of cfDNA for the outcome of ESRD patients.

Methods

A total of 289 ESRD patients on dialysis were enrolled in the study: we evaluated cfDNA, haemogram, serum iron, hepcidin, inflammatory and oxidative stress markers, and haemostasis. Events and causes of deaths were recorded throughout the follow-up period.

Results

ESRD patients, as compared with controls, presented significantly higher levels of cfDNA, hepcidin, and inflammatory and oxidative stress markers, and significantly lower values of iron and anaemia-related haemogram parameters. The all-cause mortality rate was 9.7%; compared with alive patients, deceased patients (n = 28) were older and presented significantly higher values of inflammatory markers and of cfDNA, which was almost 2-fold higher. Furthermore, cfDNA was the best predictor of all-cause mortality and cardiovascular mortality in ESRD patients, in both unadjusted and adjusted models for basic confounding factors in dialysis.

Conclusions

Our data show cfDNA to be a valuable predictive marker of prognosis in ESRD patients on dialysis treatment; high levels of cfDNA were associated with a poor outcome.

Pentraxin-3 is not related to disease severity in cirrhosis and hepatocellular carcinoma patients

The acute-phase protein pentraxin-3 (PTX3) is a component of the innate immune system. Inflammation and tissue injury increased PTX3 in the injured liver, and accordingly, circulating PTX3 was induced in patients with chronic liver diseases. In the present study, PTX3 protein was determined in systemic, hepatic, and portal vein plasma of patients with liver cirrhosis to assess a possible association between hepatic PTX3 release and extent of liver injury. However, PTX3 levels were not related to disease severity. Of note, portal PTX3 levels were higher than concentrations in the hepatic vein. PTX3 in the hepatic and portal veins was negatively correlated with factor V, antithrombin 3, and prothrombin time. PTX3 did neither correlate with C-reactive protein nor galectin-3 or resistin, whereby the latter two proteins are associated with hepatic injury. PTX3 levels were not changed in cirrhosis patients with ascites or varices and did not correlate with the hepatic venous pressure gradient. Likewise, serum PTX3 was not correlated with histological steatosis, inflammation, or fibrosis stage in patients with hepatocellular carcinoma (HCC). Moreover, PTX3 was not associated with tumor node metastasis classification in HCC. Above all, PTX3 increased in hepatic, portal, and systemic blood immediately after transjugular intrahepatic portosystemic shunt (TIPS). Higher PTX3 in portal than hepatic vein plasma and further increase after TIPS suggests that the liver eliminates PTX3 from the circulation. In summary, PTX3 is not of diagnostic value in cirrhosis and HCC patients.

Markers of Atherosclerosis in Hypertensive Patients with Less Advanced Chronic Kidney Disease

Objective: Our study aimed to validate the neutrophil-to-lymphocyte ratio (NLR) as a marker for aortic arch calcification in hypertensive patients with less advanced chronic kidney disease (CKD).

Methods: A number of forty-four hypertensive patients with chronic kidney disease (categories G3a and G3b – 2012 KDIGO nomenclature) were included in the study. Considering the presence of aortic arch calcification (AAC) on chest X-ray, the study population was divided into two groups: 27 patients AAC present and seventeen without aortic arch calcification. Laboratory data were collected for each patient and NLR was computed. Comorbidities were also recorded: stable coronary artery disease, lower extremity arterial disease and hypertensive heart disease.

Results: A positive correlation between neutrophil-to-lymphocyte ratio and aortic arch calcification in hypertensive CKD patients was identified. Furthermore, advanced age, increased alkaline phosphatase and increased erythrocyte sedimentation rate had a positive association with aortic arch calcification. We found no statistical correlation between neutrophil-to-lymphocyte ratio and other laboratory features in both groups of patients.

Conclusions: Neutrophil-to-lymphocyte ratio may be viewed as a potential risk factor for vascular calcification in patients with moderate chronic kidney disease; nevertheless, future extensive studies are necessary. In the management of hypertensive patients, general medicine might particularly benefit of this simple, readily available inflammatory marker.