Tissue factor and urokinase-type plasminogen activator system are related to the presence of cardiovascular disease in hemodialysis patients

Periodontal Health and Disease in the Context of Systemic Diseases

During recent years, considerable progress has been made in understanding the etiopathogenesis of periodontitis in its various forms and their interactions with the host. Furthermore, a number of reports have highlighted the importance of oral health and disease in systemic conditions, especially cardiovascular diseases and diabetes. In this regard, research has attempted to explain the role of periodontitis in promoting alteration in distant sites and organs. Recently, DNA sequencing studies have revealed how oral infections can occur in distant sites such as the colon, reproductive tissues, metabolic diseases, and atheromas. The objective of this review is to describe and update the emerging evidence and knowledge regarding the association between periodontitis and systemic disease and to analyse the evidence that has reported periodontitis as a risk factor for the development of various forms of systemic diseases in order to provide a better understanding of the possible shared etiopathogenetic pathways between periodontitis and the different forms of systemic diseases.

Analysis of galectin-3 levels as a source of coronary heart disease risk during periodontitis

BACKGROUND AND OBJECTIVE

Different evidence has shown that Galectins have a key role as modulators of cell surface functions and signaling in a wide range of inflammatory diseases during their preclinical stages. The aim of this study was to analyze the association and impact of periodontitis and coronary heart disease (CHD) on salivary and serum Galectin-3 in patients with periodontitis and CHD.

MATERIALS AND METHODS

For the present study, healthy controls (n = 38), periodontitis (n = 40), CHD (n = 39), and a combination of periodontitis +CHD (n = 38) patients were enrolled and analyzed. In each patient, demographic characteristics and a full-mouth clinical periodontal examination were achieved. Moreover, serum and salivary samples were collected to assess Galectin-3 and Endothelin-1 (ET-1) levels. The Jonckheere-Terpstra p-trend and Spearman's correlation tests as well as uni- and linear regression analyses were used to analyze the study data.

RESULTS

Patients with periodontitis (serum, p = .003; saliva, p < .001) and periodontitis + CHD groups (serum p = .004; saliva, p < .001) had higher median serum and salivary concentrations of Galectin-3 in comparison with CHD and healthy controls. Serum (p = .006) and salivary (p = .009) Galectin-3 levels were significantly correlated with serum ET-1. The multivariate regression analysis highlighted that periodontitis (p = .047) was the significant predictor of serum Galectin-3 levels while ET-1 (p = .028) was the significant predictor of salivary Galectin-3 levels.

CONCLUSION

The results showed that patients with periodontitis and periodontitis + CHD presented significant higher serum and salivary Galectin-3 levels in comparison with CHD patients and healthy subjects. Periodontitis and ET-1 were the significant predictors of serum and salivary Galectin-3 levels, respectively.

Independent impact of periodontitis and cardiovascular disease on elevated soluble urokinase-type plasminogen activator receptor (suPAR) levels

BACKGROUND

Previous studies have demonstrated that a soluble urokinase-type plasminogen activator receptor (suPAR) plays an essential function in leukocytes and endothelial homeostasis and, therefore, in the development of coronary heart disease (CHD) and periodontitis. The aim of this study was to analyze the impact of gingival health, periodontitis, and CHD on suPAR levels in plasma and saliva and to evaluate suPAR as a biomarker of periodontitis and CHD.

METHODS

Healthy controls (n = 33), patients with periodontitis (n = 31), CHD (n = 29), and a combination of periodontitis + CHD (n = 29) were enrolled in the present study. All patients were clinically and periodontally evaluated and regularly assessed for socioeconomic status, serum lipids, high-sensitivity C-reactive protein (hs-CRP), and for plasma and salivary suPAR levels.

RESULTS

Patients with periodontitis (P <.001) and with periodontitis + CHD (P <.001) presented higher median plasma and salivary suPAR levels compared with CHD and healthy controls. Moreover, univariate regression analysis demonstrated that hs-CRP (P <.001) and periodontitis (P <.001) had a significant negative direct effect on both plasma and salivary suPAR levels. The multivariate regression analysis showed that periodontitis was the only significant predictor of plasma suPAR (P = .035) while hs-CRP was the only significant predictor of salivary suPAR (P <.001).

CONCLUSIONS

The results of the present study demonstrated that patients with periodontitis and periodontitis + CHD presented higher suPAR levels in both plasma and saliva in comparison with healthy controls and CHD. Moreover, periodontitis and hs-CRP were the only significant predictors of the augmented suPAR levels in plasma and saliva, respectively.

Thrombolome and Its Emerging Role in Chronic Kidney Diseases

Patients with chronic kidney disease (CKD) are at an increased risk of thromboembolic complications, including myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism. These complications lead to increased mortality. Evidence points to the key role of CKD-associated dysbiosis and its effect via the generation of gut microbial metabolites in inducing the prothrombotic phenotype. This phenomenon is known as thrombolome, a panel of intestinal bacteria-derived uremic toxins that enhance thrombosis via increased tissue factor expression, platelet hyperactivity, microparticles release, and endothelial dysfunction. This review discusses the role of uremic toxins derived from gut-microbiota metabolism of dietary tryptophan (indoxyl sulfate (IS), indole-3-acetic acid (IAA), kynurenine (KYN)), phenylalanine/tyrosine (p-cresol sulfate (PCS), p-cresol glucuronide (PCG), phenylacetylglutamine (PAGln)) and choline/phosphatidylcholine (trimethylamine N-oxide (TMAO)) in spontaneously induced thrombosis. The increase in the generation of gut microbial uremic toxins, the activation of aryl hydrocarbon (AhRs) and platelet adrenergic (ARs) receptors, and the nuclear factor kappa B (NF-κB) signaling pathway can serve as potential targets during the prevention of thromboembolic events. They can also help create a new therapeutic approach in the CKD population.

The effects of citrate dialysate in hemodialysis on polymorphonuclear elastase interaction with tissue factor and its inhibitor

BACKGROUND

This study aimed to investigate whether hemodialysis (HD) affects tissue factor (TF), tissue factor pathway inhibitor (TFPI), and polymorphonuclear elastase (PMNE) in endstage renal disease (ESRD) patients when eliminating the effects of heparin. Also, to explore the interaction of TF, TFPI, and PMNE throughout a single HD session.

METHODS

We enrolled 57 ESRD patients who had undergone hemodialysis for >3 months as an experimental group. Plasma levels of TF, TFPI and PMNE were measured by ELISA in 24 ERSD patients on intermittent HD using low-molecular-weight heparin (LMWH) as anticoagulation (LMWH group) and 33 ESRD patients using citrate as anticoagulation (citrate group) at the start and at 1, 2 and 5 h of the HD session. Meanwhile,28 ESRD patients not on dialysis were enrolled as a control group and fasting venous blood samples were taken in the morning.

RESULTS

Compared with the control group, the plasma TFPI levels of the LMWH group and the citrate group were significantly higher (P=0.000, P=0.002, respectively) under baseline conditions as well as the plasma PMNE levels (P=0.001, P=0.02, respectively), whereas TF showed no difference (P=0.186). During HD with citrate, plasma TFPI decreased slightly (P=0.012) and PMNE increased significantly (P=0.008) at 1 h. The plasma TFPI levels of the citrate group correlate with PMNE at 2 and 5 h (P=0.001, P=0.008, respectively).

CONCLUSIONS

ESRD patients on HD have significantly higher TFPI and PMNE levels compared to patients not on HD under baseline conditions, while TF levels were similar between the three groups. TFPI and PMNE are differently regulated, but the plasma levels correlated during HD in the citrate group. It might be possible that PMNE plays a role in anticoagulative activity through TFPI.

Vascular Structure and Inflammation in a South African Population: The SABPA Study

Background and Objective

Inflammation plays a role in the early onset of cardiovascular disease. However, longitudinal studies on this topic, especially in South African populations, are scant. We explored whether early changes in vascular structure are associated with changes in inflammation.

Methods

We investigated 303 South African teachers aged 20-65 years at two intervals, three years apart. Standardised methods were used to determine carotid intima-media thickness (IMT) and cross-sectional wall area (CSWA) as measures of vascular structure, as well as the inflammatory markers soluble urokinase plasminogen activator receptor (suPAR), C-reactive protein (CRP) and interleukin-6 (IL-6) at baseline and follow-up.

Results

IMT and CSWA were higher, while CRP was lower at follow-up than at baseline. After adjusting for confounding factors, percent change in IMT was inversely associated with percent change in suPAR (β = -0.12, p = 0.036; adjusted R² = 0.16) only, and only in the highest tertile of percent change in suPAR (r = -0.31; p = 0.002).

Conclusion

The early structural changes observed are not related to higher inflammatory levels in this South African population. Future studies are needed to investigate the possible protective effect of suPAR on early changes in vascular structure, especially with the focus on cardiovascular disease prevention.

Elevation of Platelet and Monocyte Activity Markers of Atherosclerosis in Haemodialysis Patients Compared to Peritoneal Dialysis Patients

Purpose

The predominant cause of mortality in dialysis patients are cardiovascular events. Platelet and monocyte activity markers play an important role in cardiovascular mortality and were assessed and related to dialysis quality criteria in haemodialysis (HD) and peritoneal dialysis (PD) patients.

Methods

For this prospective comparative study, HD patients (n = 41) and PD patients (n = 10) were included. In whole blood samples, surface expression of CD62P and CD40L on platelets, tissue factor binding on monocytes, and platelet-monocyte aggregates were measured by flow cytometry. Plasma levels of MCP-1, IL-6, TNFα, and soluble CD40L were analysed by enzyme-linked immunosorbent assay.

Results

Haemodialysis patients showed a significantly higher CD62P expression on platelets (p = 0.017), significantly higher amount of platelet-monocyte aggregates (p < 0.0001), and significantly more tissue factor binding on monocytes (p < 0.0001) compared to PD patients. In PD patients, a significant correlation between Kt/V and platelet CD40L expression (r = 0.867; 0.001) and between Kt/V and platelet CD62P expression (r = 0.686; p = 0.028) was observed, while there was no significant correlation between Kt/V and tissue factor binding on monocytes and platelet-monocyte aggregates, respectively.

Conclusion

Platelet and monocyte activity markers are higher in HD patients in comparison with those in PD patients, possibly suggesting a higher risk of cardiovascular morbidity and mortality.

Indoxyl sulfate - the uremic toxin linking hemostatic system disturbances with the prevalence of cardiovascular disease in patients with chronic kidney disease

Background

During chronic kidney disease progression, kidney-specific risk factors for cardiovascular disease come into play. The present study investigated the impact of indoxyl sulfate, dietary tryptophan-derived uremic toxin, accumulated in the blood of patients with chronic kidney disease on hemostatic parameters, markers of inflammation, oxidative stress and monocyte to macrophage transition.

Methods

Fifty-one CKD patients not undergoing hemodialysis were enrolled in the study. Coagulation factors, fibrinolytic parameters, adhesion molecules, endothelial dysfunction markers, oxidative stress as well as inflammation markers were examined using immune-enzymatic method. Indoxyl sulfate levels were assessed using high-performance liquid chromatography. Biochemical parameters were determined by routine laboratory techniques using an automated analyzers. All assessed parameters were compared with controls and subjected to cross-sectional statistical analysis.

Results

Elevated concentrations of indoxyl sulfate, the vast majority of parameters affecting hemostasis, and markers of renal insufficiency conditions were observed. Part of hemostatic factors, namely tissue factor, von Willebrand factor, thrombomodulin, soluble urokinase-type plasminogen activator receptor, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion protein were correlated with the fraction of indoxyl sulfate. A significant quantity of assessed parameters showed strong correlations with superoxide-dismutase, renal insufficiency rate, C-reactive protein, and neopterin. Levels of indoxyl sulfate were independently associated with markers of impaired endothelial function (thrombomodulin, adhesion molecules), oxidative stress (superoxide-dismutase) and monocytes activation determinant (neopterin), which indicate unconventional links between these systems and the role of indoxyl sulfate. Furthermore, parameters that correlated with the levels of indoxyl sulfate (von Willebrand factor, soluble urokinase-type plasminogen activator receptor, soluble intercellular adhesion molecule-1) were positively associated with the prevalence of cardiovascular disease in a CKD patients.

Conclusions

The study demonstrated that in conditions of chronic exposure to uremic toxins, indoxyl sulfate seems to be one of the “missing links” between impaired renal function and prevalence of cardiovascular events, especially hemostatic disorders. The main functions of the action appear to be altered monocytes activation, intensified inflammatory process, and augmented oxidative stress by this uremic toxin.

Haemodiafiltration elicits less platelet activation compared to haemodialysis

Background

Mortality in patients with end-stage renal disorders is often a consequence of cardiovascular complications. Renal replacement therapies may contribute to this morbidity by promoting cellular activation. In renal failure patients peripheral blood samples were investigated for platelet and endothelial cell activation markers to compare the effects of haemodiafiltration (HDF) and haemodialysis (HD).

Methods

Overall 28 patients were included in the study. Platelet P-selectin and leukocyte - platelet heterotypic aggregates were studied by flow cytometry. Soluble P- and E-selectin values were determined by ELISA, while von Willebrand factor (vWF) antigen levels were measured by immunoturbidimetry. Statistical analysis was done by the SPSS v22 software.

Results

Platelet surface P-selectin was below 3.0 % in healthy controls, but it was higher during the dialysis after 4 h, 8 % and 14.3 % in HDF and HD, respectively. Monocyte-platelet heterotypic aggregates were significantly elevated after 4 h in both treatments, up to 69.2 % in HDF and to 82.9 % in HD. Soluble P-selectin levels were also significantly elevated by the end of both treatment procedures (p < 0.001), vWF antigen values, however, showed elevation only during HD treatment.

Conclusions

The attenuated platelet activating effects of HDF compared to HD may contribute to a less unfavourable vascular effect in this treatment modality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0364-x) contains supplementary material, which is available to authorized users.

Urine but not serum soluble urokinase receptor (suPAR) may identify cases of recurrent FSGS in kidney transplant candidates

BACKGROUND

Recently, serum soluble urokinase receptor (suPAR) has been proposed as a cause of two thirds of cases of focal segmental glomerulosclerosis (FSGS). It was noted to be uniquely elevated in cases of primary FSGS, with higher levels noted in cases that recurred after transplantation. It is also suggested as a possible target and marker of therapy.

METHODS

We studied serum and urine suPAR from pretransplantation banked samples from 86 well-characterized kidney transplant recipients and 10 healthy controls to determine its prognostic utility. Causes of native kidney disease were primary FSGS, diabetic nephropathy, membranous nephropathy, immunoglobulin A nephropathy, and autosomal dominant polycystic kidney disease. suPAR was measured using a commercially available enzyme-linked immunosorbent assay kit. Urinary suPAR was indexed to creatinine.

RESULTS

Both serum and urine suPAR correlated with proteinuria and albuminuria. Serum suPAR was found to be elevated in all transplant candidates with advanced renal disease compared with healthy controls and could not differentiate disease diagnosis. Urine suPAR was elevated in cases of recurrent FSGS compared with all other causes of end-stage renal disease. Recurrent FSGS cases had substantially higher proteinuria compared with all other cases. However, elevated urinary suPAR showed a trend in providing additional prognostic information beyond proteinuria in the small cohort of recurrent FSGS cases.

CONCLUSION

In advanced renal disease, elevated serum suPAR is not unique to FSGS cases. Urinary suPAR appears to be higher in cases of FSGS destined for recurrence and merits further evaluation.

Exploring soluble urokinase plasminogen activator receptor and its relationship with arterial stiffness in a bi-ethnic population: the SAfrEIC-study

INTRODUCTION

Elevated soluble urokinase-type plasminogen activator receptor (suPAR) indicates an inflammatory state caused by conditions such as HIV and cancer. Recently suPAR was identified as an indicator of cardiovascular disease (CVD). CVD is highly prevalent in black South Africans, but the potential role of suPAR is unknown. We investigated suPAR as a possible marker of arterial stiffness in Africans and Caucasians.

METHODS

This study involved 207 Africans and 314 Caucasians (aged 20-70 yrs). C-reactive protein (CRP) and suPAR were determined in fasting blood samples. We measured blood pressure, pulse wave velocity (PWV) and Windkessel arterial compliance (Cwk).

RESULTS

Africans displayed higher suPAR, CRP, PWV and lower Cwk (p<0.001) compared to Caucasians. SuPAR was elevated in Africans irrespective of gender and smoking. We found strong relationships between PWV and suPAR (r=0.27; p<0.001) and Cwk and suPAR (r=-0.39; p<0.001) in the whole group, but found no independent relationship of any arterial stiffness measure and suPAR in Africans after adjustment for confounders. Caucasian men indicated a weak significant independent association between Cwk and suPAR (β=-0.09; p=0.028).

CONCLUSION

Africans had higher levels of suPAR and arterial stiffness than Caucasians (p<0.001), but there was no independent relationship between arterial stiffness and suPAR in the Africans. It is speculated that due to the inflammatory role of suPAR, it will have stronger relationships with atherosclerosis, which has not yet manifested in this relatively young population group. SuPAR may therefore not be an ideal early marker of cardiovascular dysfunction, but may rather indicate established CVD.

Soluble urokinase plasminogen activator receptor as a prognostic marker in men participating in prostate cancer screening

BACKGROUND

The urokinase plasminogen activator (uPA) system is involved in tissue remodelling processes and is up-regulated in many types of malignancies. We investigated whether serum levels of different forms of soluble uPA receptor (suPAR) are associated with survival and in particular with prostate cancer and cardiovascular disease mortality.

METHODS

Using time-resolved fluorescence immunoassays, we measured intact suPAR [suPAR(I-III)] and intact plus cleaved suPAR [suPAR(I-III) + suPAR(II-III)] and thus calculated the amount of suPAR(II-III) in serum samples from 375 men participating in a prostate cancer screening trial. A total of 312 men were free of prostate cancer and 63 men had prostate cancer diagnosed at the time of screening. The cohort was followed for 15 years. We assessed survival using Kaplan-Meier estimation and Cox proportional hazards regression.

RESULTS

The mean age at blood sampling was 64 years. In total, 152 men died during follow-up. SuPAR(I-III) and suPAR(II-III) were significantly positively associated with mortality (P = 0.001 and P < 0.0001, respectively). In a Cox regression model adjusting for age and prostate cancer status, an increase in suPAR(I-III) and suPAR(II-III) by 1-unit (ln-scale) was associated with a hazard ratio (HR) of 2.26 [95% confidence interval (CI) 1.17-4.35] and 2.53 (95% CI 1.56-4.10), respectively. There was a trend towards an increased risk of death from prostate cancer in screening-detected prostate cancer patients with increased values of either suPAR form. However, this difference was not significant and the association disappeared after adjusting for age, tumour stage, tumour grade and prostate-specific antigen. Being in the highest quartile of any of the suPAR forms was associated with a highly significant increased risk of cardiovascular death, with HR adjusted for age of 3.27 (95% CI 1.38-7.73) for suPAR(I-III) quartile 4 versus quartile 1. Conclusions.  High concentrations of serum suPAR(I-III) and suPAR(II-III) were associated with poor overall survival. The association was particularly strong for death from cardiovascular disease. No similar association was found for prostate cancer after adjustment for other prognostic factors.

A novel signaling pathway: fibroblast nicotinic receptor alpha1 binds urokinase and promotes renal fibrosis

The nicotinic acetylcholine receptor alpha1 (nAChRalpha1) was investigated as a potential fibrogenic molecule in the kidney, given reports that it may be an alternative urokinase (urokinase plasminogen activator; uPA) receptor in addition to the classical receptor uPAR. In a mouse obstructive uropathy model of chronic kidney disease, interstitial fibroblasts were identified as the primary cell type that bears nAChRalpha1 during fibrogenesis. Silencing of the nAChRalpha1 gene led to significantly fewer interstitial alphaSMA(+) myofibroblasts (2.8 times decreased), reduced interstitial cell proliferation (2.6 times decreased), better tubular cell preservation (E-cadherin 14 times increased), and reduced fibrosis severity (24% decrease in total collagen). The myofibroblast-inhibiting effect of nAChRalpha1 silencing in uPA-sufficient mice disappeared in uPA-null mice, suggesting that a uPA-dependent fibroblastic nAChRalpha1 pathway promotes renal fibrosis. To further establish this possible ligand-receptor relationship and to identify downstream signaling pathways, in vitro studies were performed using primary cultures of renal fibroblasts. (35)S-Labeled uPA bound to nAChRalpha1 with a K(d) of 1.6 x 10(-8) m, which was displaced by the specific nAChRalpha1 inhibitor d-tubocurarine in a dose-dependent manner. Pre-exposure of uPA to the fibroblasts inhibited [(3)H]nicotine binding. The uPA binding induced a cellular calcium influx and an inward membrane current that was entirely prevented by d-tubocurarine preincubation or nAChRalpha1 silencing. By mass spectrometry phosphoproteome analyses, uPA stimulation phosphorylated nAChRalpha1 and a complex of signaling proteins, including calcium-binding proteins, cytoskeletal proteins, and a nucleoprotein. This signaling pathway appears to regulate the expression of a group of genes that transform renal fibroblasts into more active myofibroblasts characterized by enhanced proliferation and contractility. This new fibrosis-promoting pathway may also be relevant to disorders that extend beyond chronic kidney disease.

Evaluation of plasma urokinase-type plasminogen activator and urokinase-type plasminogen-activator receptor in patients with acute and chronic hepatitis B

INTRODUCTION

Urokinase-type plasminogen activator (uPA) and urokinase-type plasminogen activator receptor (uPAR) are known to be important factors in the pathogenesis of tumors and certain non-viral inflammatory diseases. However, their role in infectious virus diseases such as hepatitis B has been less well studied. This study aimed to test the hypothesis that the abnormalities of fibrinolysis and degradation of extracellular matrix mediated by uPA and uPAR are directly related to the inflammatory damage to liver cells caused by the hepatitis B virus. We therefore analyzed their role and clinicopathological significance in patients with acute or chronic hepatitis B.

MATERIALS AND METHODS

Eighty patients with acute or chronic hepatitis B, together with 30 healthy controls, were enrolled. uPA and uPAR in plasma were detected by commercial enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

The levels of uPA and uPAR in patients with acute or chronic hepatitis B significantly exceeded those in healthy controls (p<0.05). Patients with severe chronic hepatitis B had significantly higher levels of uPA and uPAR than those with moderate and mild chronic disease (p<0.05) and those with acute hepatitis B (p<0.05). Moreover, the plasma uPA and uPAR markedly increased in the acute stage (p<0.05) and dramatically decreased in the remission stage (p<0.05), but in all stages levels exceeded those in healthy subjects (p<0.05). In addition, the concentration of plasma uPAR was positively correlated with prothrombin (PT) (r=0.605, p<0.01) and total bilirubin (TBIL) (r=0.649, p<0.01).

CONCLUSIONS

It is suggested that the plasma levels of uPA and uPAR are closely related to the degree and period of inflammation in patients with acute or chronic hepatitis B, and that uPA and uPAR might be important indicators for disease progression.