Associations between inflammatory and angiogenic proteomic biomarkers, and cardiovascular events and mortality in relation to kidney function.

Background: The links between chronic kidney disease (CKD) and the high burden of cardiovascular disease remain unclear. We aimed to explore the association between selected inflammatory and angiogenic biomarkers, kidney function and long-term outcome in patients with an acute coronary syndrome (ACS) and to test the hypothesis that CKD status modifies this association. Methods: A total of 1293 ACS patients hospitalized between 2008 and 2015 were followed until 31 December 2017. Plasma was collected on days 1-3 after admission. A total of 13 biomarkers were a priori identified and analysed with two proteomic methods, proximity extension assay or multiple reaction monitoring mass spectrometry. Boxplots and multiple linear regression models were used to study associations between biomarkers and kidney function and adjusted standardized Cox regression with an interaction term for CKD was used to assess whether CKD modified the association between biomarkers and major adverse cardiovascular events and death (MACE+). Results: The concentrations of nine biomarkers-endothelial cell-specific molecule-1 (ESM-1), fibroblast growth factor 23 (FGF-23), fractalkine (CX3CL1), interleukin-1 receptor antagonist (IL-1RA), interleukin-18 (IL-18), monocyte chemotactic protein-1 (MCP-1), placenta growth factor (PlGF), transmembrane immunoglobulin 1 (TIM-1) and vascular endothelial growth factor A (VEGFA)-were inversely associated with kidney function. ESM-1, FGF-23 and TIM-1 showed associations with MACE+. Only FGF23 remained independently associated after adjustment for the other biomarkers (hazard ratio per standard deviation increase 1.34; 95% Bonferroni corrected confidence interval 1.19-1.50). None of the biomarkers showed an interaction with CKD. Conclusions: The concentrations of 9 of the 13 prespecified inflammatory and angiogenic proteomic biomarkers increased when kidney function declined. Only FGF-23 demonstrated an independent association with MACE+, and this association was not modified by CKD status. These findings further support FGF-23 as an independent prognostic marker in ACS patients with and without CKD.

Blood pressure in atrial fibrillation and in sinus rhythm during ambulatory blood pressure monitoring: data from the TEMPLAR project.

The coexistence of hypertension and atrial fibrillation (AF) is common and accounts for a worse prognosis. Uncertainties exist regarding blood pressure (BP) measurements in AF patients by automated oscillometric devices. The Microlife WatchBP 03 AFIB ambulatory BP monitoring (ABPM) device including an AF algorithm with each measurement was used in 430 subjects aged >65 years referred for ABPM and with assumed paroxysmal AF to perform intra-individual comparisons of BP during both AF-indicated and sinus rhythm. Only subjects with >30% of measurements indicating AF and episodes >30 min for assumed AF and for sinus rhythm were included. Mean age was 78 ± 7 years, 43% were male, 77% hypertensive, and 72% were treated. Compared to sinus rhythm, 24-h mean arterial pressure was similar (87.2 ± 9.5 vs 87.5 ± 10.6 mm Hg, p = 0.47), whereas 24-h systolic BP tended to be lower (123.6 ± 13.9 vs 124.7 ± 16.1 mm Hg, p = 0.05) and night-time diastolic BP higher (64.6 ± 10.9 vs 63.3 ± 10.4 mm Hg, p = 0.01) in assumed AF. Diastolic (not systolic) BP variability was higher in AF (p < 0.001). Results were similar with heart rates <90 and ≥90 bpm. In conclusion, this is the first study to use intra-individual comparisons of averaged BP during an ABPM in assumed paroxysmal AF and sinus rhythm. Our results imply that ABPM is feasible and informative also in patients with AF. We also suggest that an AF detection algorithm offers a new approach to evaluate the reliability of averaged BP values in AF compared to SR during an ABPM.

Prognostic importance of biomarkers associated with haemostatic, vascular and endothelial disturbances in acute coronary syndrome patients in relation to kidney function.

BACKGROUND: Patients with kidney failure have a high risk for cardiovascular events. We aimed to evaluate the prognostic importance of selected biomarkers related to haemostasis, endothelial function, and vascular regulation in patients with acute coronary syndrome (ACS), and to study whether this association differed in patients with renal dysfunction. METHODS: Plasma was collected in 1370 ACS patients included between 2008 and 2015. Biomarkers were analysed using a Proximity Extension Assay and a Multiple Reaction Monitoring mass spectrometry assay. To reduce multiplicity, biomarkers correlating with eGFR were selected a priori among 36 plasma biomarkers reflecting endothelial and vascular function, and haemostasis. Adjusted Cox regression were used to study their association with the composite outcome of myocardial infarction, ischemic stroke, heart failure or death. Interaction with eGFR strata above or below 60 ml/min/1.73 m2 was tested. RESULTS: Tissue factor, proteinase-activated receptor, soluble urokinase plasminogen activator surface receptor (suPAR), thrombomodulin, adrenomedullin, renin, and angiotensinogen correlated inversely with eGFR and were selected for the Cox regression. Mean follow-up was 5.2 years during which 428 events occurred. Adrenomedullin, suPAR, and renin were independently associated with the composite outcome. Adrenomedullin showed interaction with eGFR strata (p = 0.010) and was associated with increased risk (HR 1.88; CI 1.44-2.45) only in patients with eGFR ≥60 ml/min/ 1.73 m2. CONCLUSIONS: Adrenomedullin, suPAR, and renin were associated with the composite outcome in all. Adrenomedullin, involved in endothelial protection, showed a significant interaction with renal function and outcome, and was associated with the composite outcome only in patients with preserved kidney function.

24-hour ambulatory blood pressure telemonitoring in patients at risk of atrial fibrillation: results from the TEMPLAR project.

Hypertension is the most common risk factor for atrial fibrillation (AF). The ability to screen for potential AF during blood pressure (BP) measurement may be a valuable tool for early AF detection. This study evaluated the frequency of irregular pulse rates suggestive of AF in subjects undergoing ambulatory BP monitoring (ABPM) and compared the characteristics of patients at low risk of presumed AF vs. those at high risk. ABPM recordings were obtained in 4419 subjects aged ≥65 years visiting 304 community pharmacies, with clinically validated automated monitors equipped with an algorithm for detecting possible AF episodes during BP measurement. Subjects with <30% of the readings suggestive of AF were categorized as having a low risk of AF, and those with ≥30% of readings were classified as high risk. A total of 531 subjects (12.0%) were categorized as having a high risk of AF, with the risk increasing with advancing age. Subjects at high risk of AF had lower average systolic BP, higher average diastolic BP and pulse rate (PR), increased BP and PR variabilities, and blunted sleep-associated reductions in BP and PR. In repeated recordings, the reliability of the AF detection algorithm per se was good (kappa 0.476, p = 0.0001; intraclass correlation coefficient 0.56, p = 0.0001). Simultaneous BP measurement and screening for potential AF by ABPM in elderly people in clinical practice may help improve BP control and the detection of subjects at high risk of AF. However, a finding of presumed AF must always be confirmed by an electrocardiogram (ECG).

Aortic stiffness and aortic-brachial stiffness mismatch as markers of renal dysfunction in hypertension.

PURPOSE: The dismal combination of hypertension and chronic kidney disease potentiates both cardiovascular disease and loss of renal function. Research points to the importance of arterial and left ventricular stiffening in this process but few studies have compared aspects of central and peripheral hemodynamics in relation to renal function in hypertension. MATERIALS AND METHODS: We investigated 107 hypertensive individuals with renal function ranging from normal to severe dysfunction with pulse wave analysis to obtain central blood pressures (BP), augmentation index, carotid-femoral and carotid-radial pulse wave velocity (cfPWV, crPWV), aortic-to-brachial stiffness mismatch (cfPWV/crPWV), endothelial function by forearm flow-mediated vasodilation and myocardial microvascular function by subendocardial viability ratio, and indices of left ventricular structure (left ventricular mass index and relative wall thickness, RWT) and diastolic function (left atrial volume index, E/A, and E/é). RESULTS: Mean age was 58 years, BP 149/87 mm Hg, 9% had cardiovascular disease, and 31% were on antihypertensive treatment. Mean estimated glomerular filtration rate (eGFR) was 74 (range 130-21) ml/min × 1.73 m2. Whereas cfPWV and cfPWV/crPWV were independently related to eGFR (r = -0.20, p = 0.002, r = -0.16, p = 0.01), central diastolic BP (r = 0.21, p = 0.04), RWT (r = -0.34, p = 0.001), E/é (r = -0.39, p < 0.001) and E/A (r = 0.27, p = 0.01) were related to eGFR in bivariate correlations, but these findings were not retained in multivariate analyses. Remaining markers of hypertensive heart disease and measures of microvascular function were not related to eGFR. CONCLUSION: Increased aortic stiffness and aortic-to-brachial stiffness mismatch are independently related to reduced eGFR in hypertensive patients, suggesting an important role for aortic stiffness in the evolution of hypertension-mediated renal dysfunction. Aortic stiffness and aortic-brachial stiffness mismatch may be useful early markers to find hypertensive patients at risk for decline in renal function.

Changes in microparticle profiles by vitamin D receptor activation in chronic kidney disease - a randomized trial.

BACKGROUND: Microparticles (MPs) are biomarkers and mediators of disease through their expression of surface receptors, reflecting activation or stress in their parent cells. Endothelial markers, ICAM-1 and VCAM-1, are implicated in atherosclerosis and associated with cardiovascular risk. Chronic kidney disease (CKD) patients have endothelial dysfunction and high levels of endothelial derived MPs. Vitamin D treatment has been reported to ameliorate endothelial function in CKD patients. We aimed to examine cell specific MP profiles and concentrations of MPs expressing the atherosclerotic markers ICAM-1 and VCAM-1 after treatment with paricalcitol in patients with CKD stage 3-4. METHODS: Sub-study of the previously reported SOLID trial where 36 patients were randomly assigned to placebo, 1 or 2 µg paricalcitol, for 12 weeks. MPs were measured by flow cytometry after labelling with antibodies against endothelial (CD62E), platelet (CD62P, CD41, CD154) leukocyte (CD45) and vascular (CD54, CD106) markers. RESULTS: Patients had a mean age of 65 years with a mean eGFR of 40 mL/min/1.73m2. Concentrations of ICAM-1 positive MPs were significantly reduced by treatment (repeated measures ANOVA p = 0.04). Repeated measures MANOVA of concentrations of endothelial, platelet and leukocyte MPs showed sustained levels in the 2 µg treatment group (p = 0.85) but a decline in the 1 µg (p = 0.04) and placebo groups (p = 0.005). CONCLUSIONS: Treatment with paricalcitol reduces concentrations of ICAM-1 positive MPs. This is accompanied by sustained concentrations of all cell specific MPs in the 2 µg group, and decreasing concentrations in the other groups, possibly due to a more healthy and reactive endothelium with paricalcitol treatment.

Increased concentrations of platelet- and endothelial-derived microparticles in patients with myocardial infarction and reduced renal function- a descriptive study.

BACKGROUND: Patients with chronic kidney disease (CKD) have a high risk of recurring thrombotic events following acute myocardial infarction (AMI). Microparticles (MPs) are circulating small vesicles shed from various cells. Platelet microparticles (PMPs) reflect platelet activation and endothelial microparticles (EMPs) reflect endothelial activation or dysfunction. Both increase following AMI, and may mediate important biological effects. We hypothesized that AMI patients with CKD have further elevated PMPs and EMPs compared with non-CKD patients, despite concurrent antithrombotic treatment. METHODS: We performed a descriptive study of patients with AMI. Fasting blood samples were acquired from 47 patients on dual antiplatelet treatment. Patients were stratified by renal function: normal (H; n = 19) mean eGFR 88; moderate CKD (CKD3; n = 15) mean eGFR 47, and severe CKD (CKD4-5; n = 13) mean eGFR 20 mL/min/1.73 m2. MPs were measured by flow-cytometry and phenotyped according to size (< 1.0 µm) and expression of CD41 (GPIIb; PMPs) and CD62E (E-selectin; EMPs). In addition, expression of platelet activation markers P-selectin (CD62P) and CD40ligand (CD154) were also investigated. RESULTS: PMPs expressing CD40 ligand were higher in CKD4-5: 210 /µl (174-237); median and interquartile range; vs. group H; 101 /µl (71-134; p < 0.0001) and CKD 3: 142 /µl (125-187; p = 0.006). PMPs expressing P-selectin were higher in CKD4-5 compared with H, but not in CKD3. EMPs were higher in CKD4-5; 245 /µl (189-308) compared with H; 83 /µl (53-140; p < 0.0001) and CKD3; 197 /µl (120-245; p < 0.002). CONCLUSIONS: In AMI patients, PMPs and EMPs from activated platelets and endothelial cell are further elevated in CKD patients. This indicate impaired endothelial function and higher platelet activation in CKD patients, despite concurrent antiplatelet treatment.

Treating endothelial dysfunction with vitamin D in chronic kidney disease: a meta-analysis.

BACKGROUND: Vitamin D deficiency is common in patients with chronic kidney disease (CKD), and is associated with endothelial dysfunction and cardiovascular disease. We performed a meta-analysis to assess the effect of vitamin D treatment on flow mediated vasodilation (FMD) in CKD patients. METHODS: PubMed/Medline, Web of Science, Embase and Cochrane trials and reviews were searched systematically for randomized controlled trials (RCT:s) using any vitamin D compound, at any stage of CKD, with FMD as outcome. Fixed and random effects models were performed using the standardized mean difference effect size post treatment for each trial. Heterogeneity was assessed by I2 statistics. RESULTS: 4 trials were included, comprising 305 patients. One used both 1 and 2 µg for two intervention groups and was therefore split in two during the analysis. Patients in the included trials had a mean age of 44-65 years and were all in CKD 3 to 4. One study used cholecalciferol, the others all used paricalcitol as treatment. Study duration was 12-16 weeks. Intervention with vitamin D was associated with ameliorated FMD (STANDmean ES 0.78, 95% CI 0.55-1.01) in a fixed model. Heterogeneity was substantial (I2 = 84%). Secondary analysis with random model analysis also showed significant results. CONCLUSIONS: Short term intervention with vitamin D is associated with improvements in endothelial function, as measured by FMD. This indicates positive effects of vitamin D on vascular disease in CKD. Limitations of this meta-analysis are the small number of studies performed, and the short duration of intervention.

Vitamin D receptor activation reduces inflammatory cytokines and plasma MicroRNAs in moderate chronic kidney disease - a randomized trial.

BACKGROUND: Chronic kidney disease (CKD) is a major risk factor for cardiovascular disease (CVD), partly due to endothelial dysfunction and chronic inflammation. Vitamin D treatment in end stage renal disease is suggested to modulate the immune system and lead to improved outcomes. We and others have demonstrated that treatment with vitamin D or activated vitamin D analogues protects the endothelial function in less severe renal disease as well. Since the endothelial protection might be mediated by vitamin D effects on inflammation, we assessed levels of pro-inflammatory cytokines and micro RNAs (miRs) in patients with moderate CKD, treated with an active vitamin D analogue (paricalcitol). METHODS: Thirty-six patients with moderate CKD were randomized to 12 weeks treatment with placebo, 1 µg, or 2 µg paricalcitol daily. Cytokines were measured by Milliplex 26-plex. Total RNA was isolated from plasma and miRs were determined by quantitative reverse transcription PCR analysis. RESULTS: Selected pro-inflammatory cytokines decreased significantly following treatment, while no change was observed in the placebo group. The micro RNAs; miR 432-5p, miR 495-3p, and miR 576-5p were significantly downregulated in the active treated groups, compared to the placebo group. CONCLUSION: Paricalcitol treatment for 12 weeks in patients with moderate CKD reduces cytokines and micro RNAs involved in atherosclerosis and inflammation. The potentially protective role of vitamin D receptor activation in the inflammatory processes regarding the long-term outcomes in CKD patients warrants further studies. TRIAL REGISTRATION: SOLID study; NCT01204528 , April 27, 2010.

Paricalcitol, Microvascular and Endothelial Function in Non-Diabetic Chronic Kidney Disease: A Randomized Trial.

BACKGROUND: Vitamin D deficiency, sympathetic activation and endothelial dysfunction are associated with increased cardiovascular risk in patients with chronic kidney disease (CKD). Studies have so far failed to establish the role of vitamin D and vitamin D receptor activator (VDRA) treatment in moderate CKD. This trial was designed to assess whether VDRA treatment can ameliorate sympathetic activation and macro- and microvascular dysfunction in non-diabetic patients with moderate CKD. METHODS: We conducted a randomized controlled double-blind trial using placebo, 1 or 2 µg of paricalcitol, a VDRA, for 3 months. We assessed muscle sympathetic nerve activity (MSNA) by microneurography, pulse wave velocity (PWV) by tonometry, flow mediated vasodilatation (FMD) by brachial ultrasound, skin microcirculation assessed by iontophoresis and capillary blood velocity (CBV) by videophotometric capillaroscopy. RESULTS: Thirty-six patients with a mean age of 65 years and mean estimated glomerular filtration rate of 40 ml/min/1.73 m2 were included. We found a significant decline in endothelial function after 3 months, except in the group receiving 2 µg of paricalcitol. The higher dose (2 µg) seemed to attenuate the decline in microvascular endothelial function, assessed by iontophoresis of acetylcholine (p=0.06 for all groups, p=0.65 for the 2 µg group) and for FMD (p=0.006 for all groups, p=0.54 for the 2 µg group). We found a borderline significance (p=0.05) for improved CBV in the treated groups. We found no significant changes between treatments in MSNA, PWV or albuminuria. CONCLUSIONS: Endothelial function declined significantly over 3 months in patients with moderate CKD, and this decline could be ameliorated by VDRA treatment (NCT01204528).