The cellular composition of chronic subdural hematoma

INTRODUCTION

The pathophysiology of chronic subdural hematoma (CSDH) remains to be fully understood. Basic knowledge of the composition and features of cells in the CSDH fluid may contribute to the understanding of the seemingly complex processes involved in CSDH formation and recurrence. This study is the first to examine the composition of cells and of cellular features in both systemic blood and subdural fluid from CSDH patients. We hypothesized that the cellular composition and features in the hematoma fluid may be; 1) different from that in the systemic blood; 2) different between patients with and without recurrence; 3) and different between the first and second operation in patients with recurrent CSDH.

METHODS

Systemic blood and subdural hematoma fluid were collected from CSDH patients with and without recurrent CSDH at the time of primary and secondary surgery. Analyses of cells and cellular features included total number of white blood cells, erythroblasts, reticulocytes, platelets, neutrophilocytes, lymphocytes, monocytes, eosinophils, basophils, reticulocytes, immature granulocytes, mean corpuscular cell volume (MCV), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, hemoglobin and hematocrit.

RESULTS

Of the 85 included patients, 20 patients were operated for a recurrent CSDH within 90 days follow-up. All cells found in the systemic blood were present in the CSDH fluid, but the composition was different (p < 0.0001). MCV was higher in the hematoma fluid from the primary operation of patients later developing a recurrent CSDH compared to patients not developing recurrence (p = 0.009). Also, the percentage distribution of inflammatory cells in hematoma fluid from patients with recurrent CSDH was different between the first and second operation (p = 0.0017).

CONCLUSION

This study is the first to investigate the cellular composition of CSDH fluid. Compared to systemic blood and to a reference distribution, an increased number of immune cells were present in the hematoma fluid, supporting an inflammatory component of the CSDH pathophysiology. MCV was higher in the subdural fluid at time of the first operation of CSDH patients later developing recurrence.

CLINICAL TRIAL REGISTRATION

The study was approved by the Scientific Ethical Committee of the Capital Region of Denmark (Journal no. H-20051073.

The role of aetiology in cardiac manifestations of chronic kidney disease: the CPH-CKD ECHO study

PURPOSE

We investigated the associations between cardiac parameters and aetiologies of CKD in an exploratory study.

METHODS

The study population consisted of 883 participants, 174 controls and 709 patients with aetiologies of CKD including diabetic nephropathy/renovascular KD in diabetes mellitus, hypertensive/renovascular nephropathy, tubulointerstitial nephritis, glomerulonephritis/vasculitis, polycystic KD (PKD), and CKD of unknown origin. Echocardiographic measures included left ventricular (LV) ejection fraction, global longitudinal, area, and radial strain, E/e' ratio, and LV mass index. These were compared between each aetiological group and controls in unadjusted and adjusted analysis.

RESULTS

In unadjusted analysis, patients with diabetic nephropathy/renovascular KD in diabetes mellitus, had impaired LV ejection fraction (Median [IQR]: 56% [49.9,60.69] vs. 60.8% [57.7,64.1]), global longitudinal (mean ± SD: 13.1 ± 3.5% vs. 15.5 ± 2.6%), area (24.1 ± 5.8% vs. 28.5 ± 4.2%), and radial strain (36.2 ± 11.2% vs. 44.1 ± 9.7%), and increased LV mass index (89.1 g/m2 [71.8,104.9] vs. 69,0 g/m2 [57.9,80.8]) and E/e' ratio (10.6 [8.5,12.6] vs. 7 [5.8,8.3], p < 0.001 for all) compared with controls. Associations were similar for CKD of unknown origin. Patients with hypertensive/renovascular nephropathy had impaired global longitudinal and area strain, and higher E/e' ratio. Patients with glomerulonephritis/vasculitis had higher LV mass index, while patients with PKD had better global longitudinal strain than controls. All findings remained significant in adjusted analysis, except for the impaired global longitudinal strain in hypertensive/renovascular nephropathy.

CONCLUSION

Glomerulonephritis/vasculitis, hypertensive/renovascular nephropathy, CKD of unknown origin, and diabetic nephropathy/renovascular KD in diabetes mellitus were increasingly associated with adverse cardiac findings, while PKD and tubulointerstitial nephritis were not. Aetiology might play a role regarding the cardiac manifestations of CKD.

Discovery of plasma proteins associated with ventricular fibrillation during first ST-elevation myocardial infarction via proteomics

AIMS

The underlying biological mechanisms of ventricular fibrillation (VF) during acute myocardial infarction are largely unknown. To our knowledge, this is the first proteomic study for this trait, with the aim to identify and characterize proteins that are associated with VF during first ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

We included 230 participants from a Danish ongoing case-control study on patients with first STEMI with VF (case, n = 110) and without VF (control, n = 120) before guided catheter insertion for primary percutaneous coronary intervention. The plasma proteome was investigated using mass spectrometry-based proteomics on plasma samples collected within 24 h of symptom onset, and one patient was excluded in quality control. In 229 STEMI patients {72% men, median age 62 years [interquartile range (IQR): 54-70]}, a median of 257 proteins (IQR: 244-281) were quantified per patient. A total of 26 proteins were associated with VF; these proteins were involved in several biological processes including blood coagulation, haemostasis, and immunity. After correcting for multiple testing, two up-regulated proteins remained significantly associated with VF, actin beta-like 2 [ACTBL2, fold change (FC) 2.25, P < 0.001, q = 0.023], and coagulation factor XIII-A (F13A1, FC 1.48, P < 0.001, q = 0.023). None of the proteins were correlated with anterior infarct location.

CONCLUSION

Ventricular fibrillation due to first STEMI was significantly associated with two up-regulated proteins (ACTBL2 and F13A1), suggesting that they may represent novel underlying molecular VF mechanisms. Further research is needed to determine whether these proteins are predictive biomarkers or acute phase response proteins to VF during acute ischaemia.

Blood biomarkers improve the prediction of prevalent and incident severe chronic kidney disease

BACKGROUND

The prevalence of chronic kidney disease (CKD) is high. Identification of cases with CKD or at high risk of developing it is important to tailor early interventions. The objective of this study was to identify blood metabolites associated with prevalent and incident severe CKD, and to quantify the corresponding improvement in CKD detection and prediction.

METHODS

Data from four cohorts were analyzed: Singapore Epidemiology of Eye Diseases (SEED) (n = 8802), Copenhagen Chronic Kidney Disease (CPH) (n = 916), Singapore Diabetic Nephropathy (n = 714), and UK Biobank (UKBB) (n = 103,051). Prevalent CKD (stages 3-5) was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2; incident severe CKD as CKD-related mortality or kidney failure occurring within 10 years. We used multivariable regressions to identify, among 146 blood metabolites, those associated with CKD, and quantify the corresponding increase in performance.

RESULTS

Chronic kidney disease prevalence (stages 3-5) and severe incidence were 11.4% and 2.2% in SEED, and 2.3% and 0.2% in UKBB. Firstly, phenylalanine (Odds Ratio [OR] 1-SD increase = 1.83 [1.73, 1.93]), tyrosine (OR = 0.75 [0.71, 0.79]), docosahexaenoic acid (OR = 0.90 [0.85, 0.95]), citrate (OR = 1.41 [1.34, 1.47]) and triglycerides in medium high density lipoprotein (OR = 1.07 [1.02, 1.13]) were associated with prevalent stages 3-5 CKD. Mendelian randomization analyses suggested causal relationships. Adding these metabolites beyond traditional risk factors increased the area under the curve (AUC) by 3% and the sensitivity by 7%. Secondly, lactate (HR = 1.33 [1.08, 1.64]) and tyrosine (HR = 0.74 [0.58, 0.95]) were associated with incident severe CKD among individuals with eGFR < 90 mL/min/1.73 m2 at baseline. These metabolites increased the c-index by 2% and sensitivity by 5% when added to traditional risk factors.

CONCLUSION

The performance improvements of CKD detection and prediction achieved by adding metabolites to traditional risk factors are modest and further research is necessary to fully understand the clinical implications of these findings.

Kidney derived apolipoprotein M and its role in acute kidney injury

Aim: Apolipoprotein M (apoM) is mainly expressed in liver and in proximal tubular epithelial cells in the kidney. In plasma, apoM associates with HDL particles via a retained signal peptide and carries sphingosine-1-phosphate (S1P), a small bioactive lipid. ApoM is undetectable in urine from healthy individuals but lack of megalin receptors in proximal tubuli cells induces loss of apoM into the urine. Besides this, very little is known about kidney-derived apoM. The aim of this study was to address the role of apoM in kidney biology and in acute kidney injury. Methods: A novel kidney-specific human apoM transgenic mouse model (RPTEC-hapoMTG) was generated and subjected to either cisplatin or ischemia/reperfusion injury. Further, a stable transfection of HK-2 cells overexpressing human apoM (HK-2-hapoMTG) was developed to study the pattern of apoM secretion in proximal tubuli cells. Results: Human apoM was present in plasma from RPTEC-hapoMTG mice (mean 0.18 μM), with a significant increase in plasma S1P levels. In vitro apoM was secreted to both the apical (urine) and basolateral (blood) compartment from proximal tubular epithelial cells. However, no differences in kidney injury score was seen between RPTEC-hapoMTG and wild type (WT) mice upon kidney injury. Further, gene expression of inflammatory markers (i.e., IL6, MCP-1) was similar upon ischemia/reperfusion injury. Conclusion: Our study suggests that kidney-derived apoM is secreted to plasma, supporting a role for apoM in sequestering molecules from excretion in urine. However, overexpression of human apoM in the kidney did not protect against acute kidney injury.

Plasma activin A rises with declining kidney function and is independently associated with mortality in patients with chronic kidney disease

Background

Plasma (p-)activin A is elevated in chronic kidney disease-mineral and bone disorder (CKD-MBD). Activin A inhibition ameliorates CKD-MBD complications (vascular calcification and bone disease) in rodent CKD models. We examined whether p-activin A was associated with major adverse cardiovascular events (MACE), all-cause mortality and CKD-MBD complications in CKD patients.

Methods

The study included 916 participants (741 patients and 175 controls) from the prospective Copenhagen CKD cohort. Comparisons of p-activin A with estimated glomerular filtration rate (eGFR), coronary and thoracic aorta Agatston scores, and bone mineral density (BMD) were evaluated by univariable linear regression using Spearman's rank correlation, analysis of covariance and ordinal logistic regression with adjustments. Association of p-activin A with rates of MACE and all-cause mortality was evaluated by the Aalen-Johansen or Kaplan-Meier estimator, with subsequent multiple Cox regression analyses.

Results

P-activin A was increased by CKD stage 3 (124-225 pg/mL, P < .001) and correlated inversely with eGFR (r = -0.53, P < 0.01). P-activin A was associated with all-cause mortality [97 events, hazard ratio 1.55 (95% confidence interval 1.04; 2.32), P < 0.05] after adjusting for age, sex, diabetes mellitus (DM) and eGFR. Median follow-up was 4.36 (interquartile range 3.64-4.75) years. The association with MACE was not significant after eGFR adjustment. Agatston scores and BMD were not associated with p-activin A.

Conclusion

P-activin A increased with declining kidney function and was associated with all-cause mortality independently of age, sex, DM and eGFR. No association with MACE, vascular calcification or BMD was demonstrated.

Super-Resolution Ultrasound Imaging of Renal Vascular Alterations in Zucker Diabetic Fatty Rats during the Development of Diabetic Kidney Disease

Individuals with diabetes at risk of developing diabetic kidney disease (DKD) are challenging to identify using currently available clinical methods. Prognostic accuracy and initiation of treatment could be improved by a quantification of the renal microvascular rarefaction and the increased vascular tortuosity during the development of DKD. Super-resolution ultrasound (SRUS) imaging is an in vivo technique capable of visualizing blood vessels at sizes below 75 µm. This preclinical study aimed to investigate the alterations in renal blood vessels' density and tortuosity in a type 2 diabetes rat model, Zucker diabetic fatty (ZDF) rats, as a prediction of DKD. Lean age-matched Zucker rats were used as controls. A total of 36 rats were studied, subdivided into ages of 12, 22, and 40 weeks. Measured albuminuria indicated the early stage of DKD, and the SRUS was compared with the ex vivo micro-computed tomography (µCT) of the same kidneys. Assessed using the SRUS imaging, a significantly decreased cortical vascular density was detected in the ZDF rats from 22 weeks of age compared to the healthy controls, concomitant with a significantly increased albuminuria. Already by week 12, a trend towards a decreased cortical vascular density was found prior to the increased albuminuria. The quantified vascular density in µCT corresponded with the in vivo SRUS imaging, presenting a consistently lower vascular density in the ZDF rats. Regarding vessel tortuosity, an overall trend towards an increased tortuosity was present in the ZDF rats. SRUS shows promise for becoming an additional tool for monitoring and prognosing DKD. In the future, large-scale animal studies and human trials are needed for confirmation.

Identification of Glomerular and Plasma Apolipoprotein M as Novel Biomarkers in Glomerular Disease

Introduction

Dysregulation of sphingolipid and cholesterol metabolism contributes to the pathogenesis of glomerular diseases (GDs). Apolipoprotein M (ApoM) promotes cholesterol efflux and modulates the bioactive sphingolipid sphingosine-1-phosphate (S1P). Glomerular ApoM expression is decreased in patients with focal segmental glomerulosclerosis (FSGS). We hypothesized that glomerular ApoM deficiency occurs in GD and that ApoM expression and plasma ApoM correlate with outcomes.

Methods

Patients with GD from the Nephrotic Syndrome Study Network (NEPTUNE) were studied. We compared glomerular mRNA expression of ApoM (gApoM), sphingosine kinase 1 (SPHK1), and S1P receptors 1 to 5 (S1PR1-5) in patients (n = 84) and controls (n = 6). We used correlation analyses to determine associations between gApoM, baseline plasma ApoM (pApoM), and urine ApoM (uApoM/Cr). We used linear regression to determine whether gApoM, pApoM, and uApoM/Cr were associated with baseline estimated glomerular filtration rate (eGFR) and proteinuria. Using Cox models, we determined whether gApoM, pApoM, and uApoM/Cr were associated with complete remission (CR) and the composite of end-stage kidney disease (ESKD) or ≥40% eGFR decline.

Results

gApoM was reduced (P < 0.01) and SPHK1 and S1PR1 to 5 expression was increased (P < 0.05) in patients versus controls, consistent with ApoM/S1P pathway modulation. gApoM positively correlated with pApoM in the overall cohort (r = 0.34, P < 0.01) and in the FSGS (r = 0.48, P < 0.05) and minimal change disease (MCD) (r = 0.75, P < 0.05) subgroups. Every unit decrease in gApoM and pApoM (log2) was associated with a 9.77 ml/min per 1.73 m2 (95% confidence interval [CI]: 3.96-15.57) and 13.26 ml/min per 1.73 m2 (95% CI: 3.57-22.96) lower baseline eGFR, respectively (P < 0.01). From Cox models adjusted for age, sex, or race, pApoM was a significant predictor of CR (hazard ratio [HR]: 1.85; 95% CI: 1.06-3.23).

Conclusions

pApoM is a potential noninvasive biomarker of gApoM deficiency and strongly associates with clinical outcomes in GD.

Apolipoprotein M Attenuates Anthracycline Cardiotoxicity and Lysosomal Injury

Apolipoprotein M (ApoM) binds sphingosine-1-phosphate (S1P) and is inversely associated with mortality in human heart failure (HF). Here, we show that anthracyclines such as doxorubicin (Dox) reduce circulating ApoM in mice and humans, that ApoM is inversely associated with mortality in patients with anthracycline-induced heart failure, and ApoM heterozygosity in mice increases Dox-induced mortality. In the setting of Dox stress, our studies suggest ApoM can help sustain myocardial autophagic flux in a post-transcriptional manner, attenuate Dox cardiotoxicity, and prevent lysosomal injury.

Gestational Hypertension and High-Density Lipoprotein Function: An Explorative Study in Overweight/Obese Women of the DALI Cohort

Gestational hypertension (GHTN) is associated with an increased cardiovascular risk for mothers and their offspring later in life. High-density lipoproteins (HDL) are anti-atherogenic by promoting efflux of cholesterol from macrophages and suppression of endothelial cell activation. Functional impairment of HDL in GHTN-complicated pregnancies may affect long-term health of both mothers and offspring. We studied functional parameters of maternal and neonatal HDL in 192 obese women (pre-pregnancy BMI ≥ 29), who were at high risk for GHTN. Maternal blood samples were collected longitudinally at <20 weeks, at 24−28 and 35−37 weeks of gestation. Venous cord blood was collected immediately after birth. Maternal and cord blood were used to determine functional parameters of HDL, such as HDL cholesterol efflux capacity, activity of the vaso-protective HDL-associated enzyme paraoxonase-1, and levels of the HDL-associated anti-inflammatory apolipoprotein (apo)M. In addition, we determined serum anti-oxidative capacity. Thirteen percent of the women were diagnosed with GHTN. While we found no changes in measures of HDL function in mothers with GHTN, we observed impaired HDL cholesterol efflux capacity and paraoxonase-1 activity in cord blood, while serum antioxidant capacity was increased. Of particular interest, increased maternal paraoxonase-1 activity and apoM levels in early pregnancy were associated with the risk of developing GHTN. GHTN significantly impairs HDL cholesterol efflux capacity as well as HDL PON1 activity in cord blood and could affect vascular health in offspring. Maternal paraoxonase-1 activity and apoM levels in early pregnancy associate with the risk of developing GHTN.

Glucagon receptor antagonism impairs and glucagon receptor agonism enhances triglycerides metabolism in mice

OBJECTIVE

Treatment with glucagon receptor antagonists (GRAs) reduces blood glucose but causes dyslipidemia and accumulation of fat in the liver. We investigated the acute and chronic effects of glucagon on lipid metabolism in mice.

METHODS

Chronic effects of glucagon receptor signaling on lipid metabolism were studied using oral lipid tolerance tests (OLTTs) in overnight fasted glucagon receptor knockout (Gcgr^-/-) mice, and in C57Bl/6JRj mice treated with a glucagon receptor antibody (GCGR Ab) or a long-acting glucagon analogue (GCGA) for eight weeks. Following treatment, liver tissue was harvested for RNA-sequencing and triglyceride measurements. Acute effects were studied in C57Bl/6JRj mice treated with a GRA or GCGA 1 h or immediately before OLTTs, respectively. Direct effects of glucagon on hepatic lipolysis were studied using isolated perfused mouse liver preparations. To investigate potential effects of GCGA and GRA on gastric emptying, paracetamol was, in separate experiments, administered immediately before OLTTs.

RESULTS

Plasma triglyceride concentrations increased 2-fold in Gcgr^-/- mice compared to their wild-type littermates during the OLTT (P = 0.001). Chronic treatment with GCGR Ab increased, whereas GCGA treatment decreased, plasma triglyceride concentrations during OLTTs (P < 0.05). Genes involved in lipid metabolism were upregulated upon GCGR Ab treatment while GCGA treatment had opposite effects. Acute GRA and GCGA treatment, respectively, increased (P = 0.02) and decreased (P = 0.003) plasma triglyceride concentrations during OLTTs. Glucagon stimulated hepatic lipolysis, evident by an increase in free fatty acid concentrations in the effluent from perfused mouse livers. In line with this, GCGR Ab treatment increased, while GCGA treatment decreased, liver triglyceride concentrations. The effects of glucagon appeared independent of changes in gastric emptying of paracetamol.

CONCLUSIONS

Glucagon receptor signaling regulates triglyceride metabolism, both chronically and acutely, in mice. These data expand glucagon´s biological role and implicate that intact glucagon signaling is important for lipid metabolism. Glucagon agonism may have beneficial effects on hepatic and peripheral triglyceride metabolism.

Early diastolic strain rate and its associations with estimated glomerular filtration rate and albuminuria

Background

The ratio of early diastolic inflow to early diastolic strain rate, E/e'sr, is a novel echocardiographic measure, which has been shown to correlate better with left ventricular (LV) filling pressures than the conventionally used measure, E/e' (1). Additionally, E/e'sr has demonstrated prognostic value in various patient populations (2). Patients with chronic kidney disease (CKD) suffer frequently of diastolic dysfunction and elevated filling pressures (3). We wanted to investigate, how E/e'sr associates with two central measures of kidney function: estimated glomerular filtration rate, eGFR, and urine albumin creatinine ratio, UACR.

Methods

We enrolled a cohort of 825 ambulatory patients with CKD at the Departments of Nephrology of two university hospitals. Participants were examined with echocardiography including tissue doppler imaging. Two-dimensional speckle strain analysis was performed in all three apical standard projections. LV mass index (LVMI), E/e' and global longitudinal strain (GLS) were determined according to guidelines (4,5). Global early diastolic strain rate, e'sr, was calculated as the average of all 18 segments and indexed to early transmittal inflow velocity in order to calculate E/e'sr. Multivariable linear regression models were used to investigate associations between e'sr, E/e'sr, E/e' and kidney parameters. Models were adjusted for eGFR, UACR, LV ejection fraction (LVEF), age, sex, ever smoker, diabetes, hypertension, systolic and diastolic blood pressure (BP), heart rate and body mass index (BMI). We performed sensitivity analysis by excluding patients with known coronary artery disease (CAD) and heart failure (HF).

Results

Seventy-six patients had no measures of E/e'sr available leaving 749 for analysis. Excluding patients with CAD and/or HF (n=88) left 661 patients. For clinical and echocardiographic variables, see table. Patients with lower e'sr were older, had higher blood pressure and lower LVEF and GLS. E'sr was independently associated with eGFR and decreased 0.014 s–1 (95% CI 0.006 to 0.022, p=0.002) pr. 10 mL/min/1.73 m2 decrement of eGFR. Similarly, E/e'sr increased 1.1% (95% CI 0.2% to 19.2%) pr. 10 mL/min/1.73 m2 decrement of eGFR indicating rise in LV filling pressures. Contrary, E/e' was not independently associated with eGFR (p=0.5). Sensitivity analysis did not change the results significantly. None of the three measures were independently associated with UACR. Cubic restricted splines of e'sr, E/e'sr, E/e' over eGFR (figure) showed a non-linear relationship between E/e'sr and eGFR with accelerated increase at eGFR below 40 ml/min/1.73 m2.

Conclusion and perspectives

In patients with CKD, deformation-based e'sr and E/e'sr are independently associated with eGFR, but not with UACR. Repeated measurements and longitudinal follow-up of the cohort will provide information on the prognostic performance of these novel measures compared with conventional measures of LV filling pressure.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): The Capital Region of Denmark

Associations between Albuminuria, Estimated GFR and Cardiac Phenotype in a Cohort with Chronic Kidney Disease - The CPH-CKD ECHO Study

OBJECTIVE

Echocardiographic findings in chronic kidney disease (CKD) vary. We sought to estimate the prevalence of abnormal cardiac structure and function in patients with CKD and their association to estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (UACR).

METHODS

We prospectively enrolled 825 outpatients with non-dialysis-dependent CKD, mean age 58± 13 yrs, and 175 matched healthy controls, mean age 60±12 yrs. Echocardiography included assessment of left ventricular (LV) hypertrophy, LV ejection fraction (LVEF), global longitudinal strain (GLS) and diastolic dysfunction according to ASE/EACVI guidelines.

RESULTS

LV hypertrophy was found in 9% of patients vs. 1.7% of controls (p=0.005) was independently associated with UACR (p=0.002). Median LVEF was 59.4% (IQR 55.2, 62.8) in patients vs. 60.8% (57.7, 64.1) in controls (p=0.002). GLS was decreased in patients with eGFR <60ml/min/1.73m² (-17.6%±3.1%) vs. patients with higher eGFR (19.0%±2.2%, p<0.001), who were similar to controls. . Diastolic dysfunction was detected in 55% of patients and in 34% of controls.

LIMITATIONS

Non-random sampling, cross-sectional analysis.

CONCLUSIONS

We report lower prevalence of hypertrophy than previous studies, but similar measurements of systolic and diastolic function. Cardiac remodeling in CKD may be influenced by treatment modalities, demographics, comorbidities and renal pathology.

Coronary and extra-coronary artery calcium scores as predictors of cardiovascular events and mortality in chronic kidney disease stages 1-5: a prospective cohort study

BACKGROUND

Vascular calcification is a known risk factor for cardiovascular events and mortality in patients with chronic kidney disease (CKD). However, since there is a lack of studies examining several arterial regions at a time, we aimed to evaluate the risk of major adverse cardiovascular events (MACE) and all-cause mortality according to calcium scores in five major arterial sites.

METHODS

This was a prospective study of 580 patients from the Copenhagen CKD Cohort. Multidetector computed tomography of the coronary and carotid arteries, the thoracic aorta, the abdominal aorta, and the iliac arteries was used to determine vascular calcification at baseline. Calcium scores were divided into categories: 0, 1-100, 101-400, and > 400.

RESULTS

During the follow-up period of 4.1 years a total of 59 cardiovascular events and 64 all-cause deaths occurred. In Cox proportional hazards models adjusted for age, sex, eGFR, hypertension, diabetes mellitus, hypercholesterolemia, and smoking, only the coronary and carotid arteries, and the thoracic aorta were independent predictors of the designated endpoints. When examining the potential of calcification in the five arterial sites for predicting MACE, the difference in C-statistic was also most pronounced in these three sites, 0.21 (95% CI 0.16%-0.26%, P < 0.001), 0.26 (95% CI 0.22%-0.3%, P < 0.001), and 0.20 (95% CI 0.16%-0.24%, P < 0.001), respectively. This trend also applied to all-cause mortality.

CONCLUSIONS

The overall results, including data on specificity, suggest that calcium scores of the coronary and carotid arteries have the most potential for identifying patients with CKD at high cardiovascular risk and for evaluating new therapies.

Super-Resolution Ultrasound Imaging Provides Quantification of the Renal Cortical and Medullary Vasculature in Obese Zucker Rats: A Pilot Study

Obesity is a risk factor of chronic kidney disease (CKD), leading to alterations in the renal vascular structure. This study tested if renal vascular density and tortuosity was quantifiable in vivo in obese rats using microbubble-based super-resolution ultrasound imaging. The kidneys of two 11-week-old and two 20-week-old male obese Zucker rats were compared with age-matched male lean Zucker rats. The super-resolution ultrasound images were manually divided into inner medulla, outer medulla, and cortex, and each area was subdivided into arteries and veins. We quantified vascular density and tortuosity, number of detected microbubbles, and generated tracks. For comparison, we assessed glomerular filtration rate, albumin/creatinine ratio, and renal histology to evaluate CKD. The number of detected microbubbles and generated tracks varied between animals and significantly affected quantification of vessel density. In areas with a comparable number of tracks, density increased in the obese animals, concomitant with a decrease in glomerular filtration rate and an increase in albumin/creatinine ratio, but without any pathology in the histological staining. The results indicate that super-resolution ultrasound imaging can be used to quantify structural alterations in the renal vasculature. Techniques to generate more comparable number of microbubble tracks and confirmation of the findings in larger-scale studies are needed.

Association between plasma apolipoprotein M and cardiac autonomic neuropathy in type 1 diabetes

AIM

Diabetes may lead to severe complications e.g. cardiac autonomic neuropathy (CAN) characterized by an increased risk of cardiovascular mortality. CAN is diagnosed by a decreased heart rate viability (HRV). Sphingosine-1-Phosphate (S1P) carried by the HDL-associated apolipoprotein M (apoM) is linked to a reduction in the heart rate, and treatment with an S1P-agonist increases HRV. The present study aimed to investigate if plasma apoM was associated with an increased risk of CAN.

METHODS

The study includes 278 individuals with Type 1 Diabetes recruited from Steno Diabetes Center in Copenhagen from 2010 to 2012.

RESULTS

A change of 0.1 µM plasma apoM was associated with the diagnosis of CAN (Odds ratio: 1.11 (1.02; 1.21), p = 0.013). ApoM plasma levels were also positively associated with CAN when adjusted for age and gender (Odds ratio: 1.11 (1.02; 1.21), p = 0.013) as well as lipids, beta-blockers, blood pressure, and alcohol (Odds ratio: 1.14 (1.04; 1.26), p = 0.005) and Hbga1c and time with diabetes (Odds ratio: 1.13 (1.02; 1.25), p = 0.01). Plasma apoM was also associated with a significantly lower SDNN as well as high frequency power in all adjusted models.

CONCLUSION

Increased plasma apoM was associated with an increased risk of CAN as well as a significant reduction in HRV indices. This could represent changes in parasympathetic activity, but, further studies are needed to also explore additional molecular alterations behind such observations.

The metabolic signature of cardiovascular disease and arterial calcification in patients with chronic kidney disease

BACKGROUND AND AIMS

The relationship between chronic kidney disease (CKD) and cardiovascular events is well-established. Clinically recognised risk factors of cardiovascular disease cannot fully explain this association. The objective of the present cross-sectional study was to investigate associations between serum metabolites and prevalent cardiovascular disease, as well as subclinical cardiovascular disease measured as coronary artery calcium score (CACS) in patients with CKD.

METHODS

More than 200 preselected metabolites were quantified using nuclear magnetic resonance spectroscopy in 725 patients and 174 controls from the Copenhagen CKD Cohort. CACS was determined by computed tomography.

RESULTS

Mean age of patients was 57.8 years, and 444 (61.3%) were men. Most of patients had hypercholesterolemia, and 133 (18.3%) had type 2 diabetes. Overall, 85 metabolites were significantly associated with prevalent cardiovascular disease in a model adjusted for eGFR, age, and sex, as well as Bonferroni correction for multiple testing (p < 0.001). After further adjusting for diabetes, BMI, smoking, and cholesterol-lowering medication, the significance was lost for all but six metabolites (concentration of ApoA-1, cholesterol in total HDL and HDL2, total lipids and phospholipids in large HDL particles, and the ratio of phospholipids to total lipids in smaller VLDL particles). Of the 85 metabolites associated with prevalent cardiovascular disease, 71 were also associated with CACS in a similar pattern. Yet, in the model adjusted for all seven cardiovascular risk factors, only serum glucose levels and the ratio of triglycerides to total lipids in larger LDL particles remained significant.

CONCLUSIONS

In patients with CKD, associations with prevalent cardiovascular disease were mainly found for HDL-related metabolites, while CACS was associated with glucose levels and increased triglycerides to total lipids ratio in LDL particles.

The Arg82Cys polymorphism of the protein nepmucin implies a role in HDL metabolism

Context

Blood lipid levels are linked to the risk of cardiovascular disease and regulated by genetic factors. A low-frequency polymorphism Arg82Cys (rs72836561) in the membrane protein nepmucin, encoded by CD300LG, is associated with lower fasting concentration of high-density lipoprotein cholesterol (HDLc) and higher fasting triglycerides. However, whether the variant is linked to postprandial lipids and glycemic status remains elusive.

Objective

Here, we augment the genetic effect of Arg82Cys on fasting plasma concentrations of HDL subclasses, postprandial lipemia after a standardized high-fat meal, and glycemic status to further untangle its role in HDL metabolism.

Methods

We elucidated fasting associations with HDL subclasses in a population-based cohort study (Oxford BioBank, OBB), including 4522 healthy men and women. We investigated fasting and postprandial consequences on HDL metabolism in recall-by-genotype (RbG) studies (fasting: 20 carrier/20 noncarrier; postprandial: 7 carrier/17 noncarrier), and shed light on the synergistic interaction with glycemic status.

Results

A lower fasting plasma concentration of cholesterol in large HDL particles was found in healthy male carriers of the Cys82 polymorphism compared to noncarriers, both in the OBB (P = .004) and RbG studies (P = .005). In addition, the Cys82 polymorphism was associated with low fasting plasma concentrations of ApoA1 (P = .008) in the OBB cohort. On the contrary, we did not find differences in postprandial lipemia or 2-hour plasma glucose levels.

Conclusion

Taken together, our results indicate an association between the Arg82Cys variant and a lower concentration of HDL particles and HDLc, especially in larger HDL subclasses, suggesting a link between nepmucin and HDLc metabolism or maturation.

Endothelial-Specific Loss of Sphingosine-1-Phosphate Receptor 1 Increases Vascular Permeability and Exacerbates Bleomycin-induced Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease which leads to significant morbidity and mortality from respiratory failure. The two drugs currently approved for clinical use slow the rate of decline in lung function but have not been shown to halt disease progression or reverse established fibrosis. Thus, new therapeutic targets are needed. Endothelial injury and the resultant vascular permeability are critical components in the response to tissue injury and are present in patients with IPF. However, it remains unclear how vascular permeability affects lung repair and fibrosis following injury. Lipid mediators such as sphingosine-1-phosphate (S1P) are known to regulate multiple homeostatic processes in the lung including vascular permeability. We demonstrate that endothelial cell-(EC) specific deletion of the S1P receptor 1 (S1PR1) in mice (EC-S1pr1-/-) results in increased lung vascular permeability at baseline. Following a low-dose intratracheal bleomycin challenge, EC-S1pr1-/- mice had increased and persistent vascular permeability compared with wild-type mice, which was strongly correlated with the amount and localization of resulting pulmonary fibrosis. EC-S1pr1-/- mice also had increased immune cell infiltration and activation of the coagulation cascade within the lung. However, increased circulating S1P ligand in ApoM-overexpressing mice was insufficient to protect against bleomycin-induced pulmonary fibrosis. Overall, these data demonstrate that endothelial cell S1PR1 controls vascular permeability in the lung, is associated with changes in immune cell infiltration and extravascular coagulation, and modulates the fibrotic response to lung injury.

Left ventricular structure and function in patients with chronic kidney disease assessed by 3D echocardiography: the CPH-CKD ECHO study

Cardiovascular disease is the leading cause of mortality amongst patients with chronic kidney disease (CKD). This is the first study using 3-dimensional echocardiography (3DE) to investigate associations between adverse changes of the left ventricle, and different stages of CKD. Participants were recruited from the Copenhagen CKD cohort study and the Herlev-Gentofte CKD cohort study. Patients were stratified according to GFR category (G1 + 2: eGFR ≥ 60 mL/min/1.73 m2, G3: eGFR = 30-59 mL/min/1.73 m2, and G4 + 5: eGFR ≤ 29 mL/min/1.73 m2), and according to albuminuria (A1: UACR < 30 mg/g, A2: 30-300 mg/g, A3: > 300 mg/g). Echocardiograms were analysed for left ventricular (LV) mass index (LVMi), LV ejection fraction (LVEF), and global strain measures. In adjusted analysis, eGFR groups were adjusted for confounders and albuminuria category, while albuminuria groups were adjusted for confounders and GFR category. The study population consisted of 662 outpatients with CKD and 169 controls. Mean age was 57 ± 13 years, and 61% were males. Mean LVEF and global longitudinal strain (GLS) were increasingly impaired across eGFR groups: LVEF = 60.1%, 58.4%, and 57.8% (p = 0.013), GLS =  - 16.1%, - 14.8%, and - 14.6% (p < 0.0001) for G1 + 2, G3, and G4 + 5. LVMi and prevalence of LV hypertrophy increased with albuminuria severity: mean LVMi = 87.9 g/m2, 88.1 g/m2, and 92.1 g/m2 (p = 0.007) from A1-3. Adjusted analysis confirmed reduced LVEF in G3 compared with G1 + 2, and increased LVMi in A3 compared with A1. Increasingly impaired eGFR was associated with adverse changes in LV systolic function, while albuminuria was associated with adverse changes in LV mass assessed by 3DE. Their associations were independent of each other.

Carotid plaque thickness is increased in chronic kidney disease and associated with carotid and coronary calcification

BACKGROUND

Chronic kidney disease accelerates both atherosclerosis and arterial calcification. The aim of the present study was to explore whether maximal carotid plaque thickness (cPTmax) was increased in patients with chronic kidney disease compared to controls and associated with cardiovascular disease and severity of calcification in the carotid and coronary arteries.

METHODS

The study group consisted of 200 patients with chronic kidney disease stage 3 from the Copenhagen Chronic Kidney Disease Cohort and 121 age- and sex-matched controls. cPTmax was assessed by ultrasound and arterial calcification by computed tomography scanning.

RESULTS

Carotid plaques were present in 58% of patients (n = 115) compared with 40% of controls (n = 48), p = 0.002. Among participants with plaques, cPTmax (median, interquartile range) was significantly higher in patients compared with controls (1.9 (1.4-2.3) versus 1.5 (1.2-1.8) mm), p = 0.001. Cardiovascular disease was present in 9% of patients without plaques (n = 85), 23% of patients with cPTmax 1.0-1.9 mm (n = 69) and 35% of patients with cPTmax >1.9 mm (n = 46), p = 0.001. Carotid and coronary calcium scores >400 were present in 0% and 4%, respectively, of patients with no carotid plaques, in 19% and 24% of patients with cPTmax 1.0-1.9 mm, and in 48% and 53% of patients with cPTmax >1.9 mm, p<0.001.

CONCLUSIONS

This is the first study showing that cPTmax is increased in patients with chronic kidney disease stage 3 compared to controls and closely associated with prevalent cardiovascular disease and severity of calcification in both the carotid and coronary arteries.

The apoM/S1P Complex-A Mediator in Kidney Biology and Disease?

Kidney disease affects more than 10% of the population, can be both acute and chronic, and is linked to other diseases such as cardiovascular disease, diabetes, and sepsis. Despite the detrimental consequences for patients, no good treatment options directly targeting the kidney are available. Thus, a better understanding of the pathology and new treatment modalities are required. Accumulating evidence suggests that the apolipoprotein M/sphingosine-1-phosphate (apoM/S1P) axis is a likely drug target, but significant gaps in our knowledge remain. In this review, we present what has so far been elucidated about the role of apoM in normal kidney biology and describe how changes in the apoM/S1P axis are thought to affect the development of kidney disease. ApoM is primarily produced in the liver and kidneys. From the liver, apoM is secreted into circulation, where it is attached to lipoproteins (primarily HDL). Importantly, apoM is a carrier of the bioactive lipid S1P. S1P acts by binding to five different receptors. Together, apoM/S1P plays a role in several biological mechanisms, such as inflammation, endothelial cell permeability, and lipid turnover. In the kidney, apoM is primarily expressed in the proximal tubular cells. S1P can be produced locally in the kidney, and several of the five S1P receptors are present in the kidney. The functional role of kidney-derived apoM as well as plasma-derived apoM is far from elucidated and will be discussed based on both experimental and clinical studies. In summary, the current studies provide evidence that support a role for the apoM/S1P axis in kidney disease; however, additional pre-clinical and clinical studies are needed to reveal the mechanisms and target potential in the treatment of patients.

Apolipoprotein M and Sphingosine-1-Phosphate Receptor 1 Promote the Transendothelial Transport of High-Density Lipoprotein

Objective: ApoM enriches S1P (sphingosine-1-phosphate) within HDL (high-density lipoproteins) and facilitates the activation of the S1P1 (S1P receptor type 1) by S1P, thereby preserving endothelial barrier function. Many protective functions exerted by HDL in extravascular tissues raise the question of how S1P regulates transendothelial HDL transport. Approach and Results: HDL were isolated from plasma of wild-type mice, Apom knockout mice, human apoM transgenic mice or humans and radioiodinated to trace its binding, association, and transport by bovine or human aortic endothelial cells. We also compared the transport of fluorescently-labeled HDL or Evans Blue, which labels albumin, from the tail vein into the peritoneal cavity of apoE-haploinsufficient mice with (apoE-haploinsufficient mice with endothelium-specific knockin of S1P1) or without (control mice, ie, apoE-haploinsufficient mice without endothelium-specific knockin of S1P1) endothelium-specific knockin of S1P1. The binding, association, and transport of HDL from Apom knockout mice and human apoM-depleted HDL by bovine aortic endothelial cells was significantly lower than that of HDL from wild-type mice and human apoM-containing HDL, respectively. The binding, uptake, and transport of 125I-HDL by human aortic endothelial cells was increased by an S1P1 agonist but decreased by an S1P1 inhibitor. Silencing of SR-BI (scavenger receptor BI) abrogated the stimulation of 125I-HDL transport by the S1P1 agonist. Compared with control mice, that is, apoE-haploinsufficient mice without endothelium-specific knockin of S1P1, apoE-haploinsufficient mice with endothelium-specific knockin of S1P1 showed decreased transport of Evans Blue but increased transport of HDL from blood into the peritoneal cavity and SR-BI expression in the aortal endothelium. Conclusions: ApoM and S1P1 promote transendothelial HDL transport. Their opposite effect on transendothelial transport of albumin and HDL indicates that HDL passes endothelial barriers by specific mechanisms rather than passive filtration.

Apolipoprotein M and its impact on endothelial dysfunction and inflammation in the cardiovascular system

Apolipoprotein M (apoM) is a member of the lipocalin superfamily and is predominantly associated with high-density lipoprotein (HDL). It was found that apoM is the chaperon to the bioactive sphingolipid, sphingosine-1-phosphate (S1P). Several studies have since contributed to expand the knowledge on apoM, S1P, and the apoM/S1P-complex in cardiovascular diseases. For instance, the HDL-bound apoM/S1P complex serves as a bridge between HDL and endothelial cells, maintaining a healthy endothelial barrier. Evidence indicates, however, that the apoM/S1P complex may has both protective and harmful effects on the cardiovascular system, which suggests the need for more research to understand the interplay between these molecules. This review aims to shed light on the most recent findings on apoM/S1P-signaling and its impact on endothelial dysfunction, inflammation, and cardiovascular diseases. Finally, it will be discussed whether drugs that target apoM and/or S1P-signaling may be beneficial to patients with cardiovascular and inflammatory diseases.

Study protocol: long-term effect of the New Nordic Renal Diet on phosphorus and lipid homeostasis in patients with chronic kidney disease, stages 3 and 4: a randomised controlled trial

INTRODUCTION

Chronic kidney disease (CKD) causes severe disturbances in phosphate metabolism. New Nordic Renal Diet (NNRD) is a new dietary concept designed by the present research group that aims to offer patients with moderate CKD a whole food approach with a markedly reduction in dietary phosphorus intake, corresponding to 850 mg/day. The present protocol describes a randomised controlled trial aiming to test the long-term effects of dietary intervention with NNRD versus a non-restricted habitual diet on important parameters of phosphorus and lipid homeostasis.

METHODS AND ANALYSIS

This trial will be executed at the Department of Nephrology, Rigshospitalet, University of Copenhagen, Denmark. Sixty patients aged >18 years with CKD stages 3 and 4 (estimated glomerular filtration rate between 15 and 45 mL/min) will be recruited and randomly assigned to the intervention or control group. The other inclusion criterion includes a medically stable condition for at least 2 months prior to the start of the study. Exclusion criteria are treatment with phosphate binders, metabolic disorders that require specific dietary regulation, pregnancy and breast feeding, any types of food allergies or those who are vegans. The observation period is 26 weeks including seven study visits at the outpatient clinic combined with a weekly telephone consultation in both groups. A follow-up visit 3 months after study completion finalises the intervention. The primary outcome is the difference in the change in 24-hour urine phosphorus excretion from baseline to week 26 between the two study groups. Secondary outcomes include changes in phosphate-related and lipid metabolism-related blood and urine biochemistry, blood pressure and body composition. Moreover, we wish to explore adherence to the diet as well as quality of life.

ETHICS AND DISSEMINATION

The study has been approved by the Scientific Ethical Committee of the Capital Region of Denmark and the Danish Data Protection Agency. The results of the studies will be presented at national and international scientific meetings, and publications will be submitted to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (wwwclinicaltrialsgov) Registry (NCT04579315).

PROTOCOL VERSION

The protocol, version 2, has been approved by the Ethical Committee Denmark on 18 September 2020. The protocol has also been approved by Data Protection Regulation and Data Protection Law on 15 September 2020. This study protocol is in accordance with the Standard Protocol Items: Recommendations for International Trials.

MO339KIDNEY DERIVED APOM AND ITS ROLE IN ACUTE KIDNEY INJURY

Background and Aims

Acute kidney injury is a severe disease with detrimental outcomes. The underlying ethiology is still elusive and besides dialysis, treatment options are poor.

Apolipoprotein M (apoM) is mainly expressed in liver and in proximal tubular epithelial cells in the kidney. In plasma, apoM associates with HDL particles via a retained signal peptide. ApoM is a carrier of sphingosine-1-phosphate (S1P), a small bioactive lipid involved in e.g. angiogenesis, lymphocyte trafficking, and vascular barrier function. Recently, it was shown that apoM/S1P protects against development of liver and lung fibrosis. In urine, apoM is normally undetectable in both wild type mice and healthy humans. However, lack of megalin receptors in proximal tubuli induces loss of apoM into the urine. The biological function of kidney-derived apoM is unknown, but it has been hypothesized that apoM might be secreted to the pre-urine to sequester molecules, such as S1P, from secretion.

The aim of this study was to unravel the role of apoM in kidney biology and in acute kidney injury.

Method

A novel kidney specific human apoM transgenic mouse (RPTEC-hapoMTG), was generated by expressing human apoM under the control of the proximal tubular epithelial cell specific Sglt2 promoter. The effect of kidney specific apoM overexpression on acute kidney injury was accessed by inducing either cisplatin or ischemia/reperfusion injury. Further, a stable cell line of HK-2 cells overexpressing hapoM (HK-2hapoM-TG) was generated and the cells were cultured on transwells to assess the secretion of apoM to respectively the apical and basolateral site.

Results

hapoM was present in plasma from RPTEC-hapoMTG mice (mean 0.18 μM), indicating that kidney-derived apoM can be secreted to plasma. When assessing the secretion of hapoM from proximal tubular epithelial cells in vitro, studies support that apoM can be secreted to both the apical (urine) and basolateral (blood) compartment. No differences in kidney injury markers (plasma urea and creatinine) between RPTEC-hapoMTG and wild type (WT) mice subjected to cisplatin injections, or in kidney injury score determined by histological evaluation was found. Similar, we could not detect any histological difference between RPTEC-hapoMTG and WT mice after ischemia/reperfusion injury, and overexpression of hapoM did not affect kidney gene expression of inflammatory markers (i.e. IL6, MCP-1) compared to WT mice.

Conclusion

Our study suggests that apoM can be secreted to both the apical and basolateral compartment, supporting a role for apoM in sequestering molecules from secretion in urine.

Transgenic overexpression of apoM in proximal tubular epithelial cells of mice did not protect against acute kidney injury.

MO145CAROTID PLAQUE THICKNESS COMPARED WITH SEVERITY OF CAROTID AND CORONARY ARTERY CALCIFICATION IN PATIENTS WITH CHRONIC KIDNEY DISEASE STAGE 3

Background and Aims

Chronic kidney disease (CKD) accelerates both atherosclerosis and arterial calcification. The aim of the present study was to explore whether maximal carotid plaque thickness (cPT max) was increased in patients with CKD stage 3 compared to controls and associated with cardiovascular disease and severity of calcification in the carotid and coronary arteries.

Method

The study group consisted of 200 patients with CKD stage 3 from the Copenhagen CKD Cohort and 121 age- and sex-matched controls. cPT max was assessed by ultrasound and arterial calcification by computed tomography scanning.

Results

Carotid plaques were present in 58% of patients (n=115) compared with 40% of controls (n=48), P=0.002. Among participants with plaques, cPT max (median, interquartile range) was significantly higher in patients compared with controls (1.9 (1.4-2.3) versus 1.5 (1.2-1.8) mm, P=0.001. Cardiovascular disease was present in 9.4% of patients without plaques (n=85), 23.2% of patients with cPT max 1.0-1.9 mm (n=69) and 34.8% of patients with cPT max &gt;1.9 mm (n=46), P=0.001.

Carotid and coronary calcium scores &gt;400 were present in 0.0% and 4.0%, respectively, of patients with no carotid plaques, in 19.1% and 24.2% of patients with cPT max 1.0-1.9 mm, and in 47.5% and 52.6% of patients with cPT max &gt;1.9 mm, P&lt;0.001.

Conclusion

This is the first study showing that cPT max is increased in patients with CKD stage 3 compared to controls and closely associated with prevalent cardiovascular disease and severity of calcification in both the carotid and coronary arteries.

FC 060METABOLIC PROFILING AS A MARKER OF CARDIOVASCULAR DISEASE AND ARTERIAL CALCIFICATION IN THE COPENHAGEN CHRONIC KIDNEY DISEASE COHORT

Background and Aims

The relation between chronic kidney disease and adverse cardiovascular events is well-established. It is also known that traditional risk factors of cardiovascular disease such as smoking, low-density lipoprotein (LDL) cholesterol and increased blood pressure, cannot fully explain the increased cardiovascular burden observed in patients with chronic kidney disease. In addition, patients with chronic kidney disease do not demonstrate typical clinical symptoms of cardiovascular disease. Thus, good biomarkers for identifying patients at risk and a better understanding of the pathophysiology leading to cardiovascular disease in patients with chronic kidney disease are needed. The objective of the present study was to investigate associations between plasma metabolites and prevalent cardiovascular disease, as well as subclinical cardiovascular disease measured as coronary artery calcification score (CACS), in patients with chronic kidney disease.

Method

More than 200 metabolic biomarkers, including subclasses of lipoproteins as well as the lipid composition of these, were quantified using nuclear magnetic resonance spectroscopy in 725 patients and 174 controls from the Copenhagen Chronic Kidney Disease Cohort, a single-centre prospective, observational study of non-dialysis patients with stage 1-5 chronic kidney disease. Associations between metabolites and prevalent cardiovascular disease and between metabolites and CACS were determined using multivariable logistic regression and linear regression, respectively. The statistical models were adjusted for traditional cardiovascular risk factors and multiple testing. CACS was determined by CT-scannning and calcium scores were subsequently divided into categories of 0 (no calcification), 1-100, 101-400 and &gt; 400.

Results

When comparing metabolite concentrations in patients with controls, patients presented with the expected pattern of dyslipidaemia in CKD. We found that they had increased plasma triglyceride concentrations, mainly due to an increase in the triglyceride concentration in very low-density lipoprotein (VLDL) particles, while the concentration of cholesterol in high-density lipoprotein (HDL) particles was decreased.

Overall, 85 metabolites were significantly associated with prevalent cardiovascular disease in a model adjusted for eGFR, age and sex (p &lt; 0.001). After further adjusting for diabetes, body mass index, smoking and cholesterol-lowering medication, the significance was lost for all but six metabolites (p &lt; 0.001). The consistent inverse associations with metabolites were primarily involved in HDL metabolism (e.g. ApoA-1, HDL-C and HDL-2). This also applied to the concentration of total lipids in large HDL particles, the concentration of phospholipids in large HDL particles and the the ratio of phospholipids to total lipids in very small VLDL particles. Of the 84 metabolites associated with prevalent cardiovascular disease, 71 were also associated with CACS in a similar pattern. Yet, in the model adjusted for all seven cardiovascular risk factors, only plasma glucose levels as well as the triglyceride content of larger LDL particles remained significant.

Conclusion

In this study we identified metabolites associated with prevalent cardiovascular disease and subclinical cardiovascular disease (CACS) in patients with CKD. For prevalent cardiovascular disease associations were mainly found for HDL associated metabolites, while CACS was associated with an increase in the triglyceride content of LDL particles and glucose. Further work needs to be done to establish whether these associations are merely a consequence of the cardiovascular burden or whether there is a causal relation.

Increased plasma apoM levels impair triglyceride turnover in mice

OBJECTIVE

Apolipoprotein M (apoM) is an essential transporter of plasma Sphingosine-1-Phosphate (S1P), typically attached to all lipoprotein classes, but with a majority bound to high density lipoproteins (HDL). ApoM-deficient mice display an increased activity in brown adipose tissue and a concomitant fast turnover of triglycerides. In what manner apoM/S1P affect the triglyceride metabolism is however still unknown and explored in the present study.

METHODS

Triglyceride turnover and potentially associated metabolic pathways were studied in the female human apoM transgenic mouse model (apoM-Tg) with increased plasma apoM and S1P levels. The model was compared with wild type (WT) mice.

RESULTS

ApoM-Tg mice had a reduced plasma triglyceride turnover rate and a lower free fatty acid uptake in subcutaneous adipocytes compared to WT mice. Screening for potential molecular mechanisms furthermore revealed a reduction in plasma lipase activity in apoM-Tg animals. Overexpression of apoM also reduced the plasma levels of fibroblast growth factor 21 (FGF21).

CONCLUSIONS

The study features the significant role of the apoM/S1P axis in maintaining a balanced triglyceride metabolism. Further, it also highlights the risk of inducing dyslipidaemia in patients receiving S1P-analouges and additionlly emphasizes the apoM/S1P axis as a potential therapeutic target in treatment of hypertriglyceridemia.

Apolipoprotein M-A Marker or an Active Player in Type II Diabetes?

Apolipoprotein M (apoM) is a member of the lipocalin superfamily and an important carrier of the small bioactive lipid sphingosine-1-phosphate (S1P). The apoM/S1P complex is attached to all lipoproteins, but exhibits a significant preference for high-density lipoproteins. Although apoM, S1P, and the apoM/S1P complex have been discovered more than a decade earlier, the overall function of the apoM/S1P complex remains controversial. Evidence suggests that the complex plays a role in inflammation and cholesterol metabolism and is important for maintaining a healthy endothelial barrier, regulating the turnover of triglycerides from lipoproteins, and reducing cholesterol accumulation in vessel walls. Recent studies have also addressed the role of apoM and S1P in the development of diabetes and obesity. However, limited evidence is available, and the data published so far deviates. This review discusses the specific elements indicative of the protective or harmful effects of apoM, S1P, and the apoM/S1P complex on type 2 diabetes development. Since drugs targeting the S1P system and its receptors are available and could be potentially used for treating diabetes, this research topic is a pertinent one.

Regional distribution and severity of arterial calcification in patients with chronic kidney disease stages 1-5: a cross-sectional study of the Copenhagen chronic kidney disease cohort

BACKGROUND

Patients with chronic kidney disease (CKD) and arterial calcification are considered at increased risk of adverse cardiovascular outcomes. However, the optimal site for measurement of arterial calcification has not been determined. The primary aim of this study was to examine the pattern of arterial calcification in different stages of CKD.

METHODS

This was an observational, cross-sectional study that included 580 individuals with CKD stages 1-5 (no dialysis) from the Copenhagen CKD Cohort. Calcification of the carotid, coronary and iliac arteries, thoracic and abdominal aorta was assessed using non-contrast multidetector computed tomography scans and quantified according to the Agatston method. Based on the distribution of Agatston scores in the selected arterial region, the subjects were divided into calcium score categories of 0 (no calcification), 1-100, 101-400 and > 400.

RESULTS

Participants with CKD stages 3-5 had the highest prevalence of calcification and the highest frequency of calcium scores > 400 in all arterial sites. Calcification in at least one arterial site was present in > 90% of patients with CKD stage 3. In all five CKD stages prevalence of calcification was greatest in both the thoracic and abdominal aorta, and in the iliac arteries. These arterial sites also showed the highest calcium scores. High calcium scores (> 400) in all five arterial regions were independently associated with prevalent cardiovascular disease. In multivariable analyses, after adjusting for cardiovascular risk factors, declining creatinine clearance was associated with increasing calcification of the coronary arteries (p = 0.012) and the thoracic aorta (p = 0.037) only.

CONCLUSIONS

Arterial calcification is highly prevalent throughout all five CKD stages and is most prominent in both the thoracic and abdominal aorta, and in the iliac arteries. Follow-up studies are needed to explore the potential of extracardiac calcification sites in prediction of cardiovascular events in the CKD population.

Vascular function in adults with cyanotic congenital heart disease

BACKGROUND

Patients with cyanotic congenital heart disease (CCHD) may have a low burden of atherosclerosis. Endothelial dysfunction is an early stage of atherosclerosis and endothelial function is previously studied in smaller CCHD groups with different techniques and variable results. We aimed to examine endothelial function and carotid atherosclerosis in a larger group of CCHD patients.

METHODS

This multicentre study assessed endothelial function in adults with CCHD and controls by measuring the dilatory response of the brachial artery to post-ischemic hyperaemia (endothelium-dependent flow-mediated-vasodilatation (FMD)), and to nitroglycerin (endothelium-independent nitroglycerin-induced dilatation (NID)). Flow was measured at baseline and after ischaemia (reactive hyperaemia). Carotid-intima-media-thickness (CIMT), prevalence of carotid plaque and plaque thickness (cPT-max) were evaluated ultrasonographically. Lipoproteins, inflammatory and vascular markers, including sphingosine-1-phosphate (S1P) were measured.

RESULTS

Forty-five patients with CCHD (median age 50 years) and 45 matched controls (median age 52 years) were included. The patients presented with lower reactive hyperaemia (409 ± 114% vs. 611 ± 248%, p < 0.0001), however preserved FMD response compared to controls (106.5 ± 8.3% vs. 106.4 ± 6.1%, p = 0.95). In contrast, NID was lower in the patients (110.5 ± 6.1% vs. 115.1 ± 7.4%, p = 0.053). There was no difference in CIMT, carotid plaque or cPT-max. The patients presented with lower high-density-lipoprotein cholesterol, and higher level of inflammatory markers and S1P.

CONCLUSION

Adults with CCHD had preserved FMD in the brachial artery, but impaired NID response and lower reactive hyperaemia than controls. The preserved FMD and the comparable prevalence of carotid atherosclerosis indicate that CCHD patients have the same risk of atherosclerosis as controls.

Apolipoprotein M and Risk of Type 2 Diabetes

CONTEXT

Recent studies have discovered a role of apolipoprotein M (apoM) in energy metabolism, and observational analyses in humans suggest an association with type 2 diabetes. The causal relationship remains however elusive.

OBJECTIVE

To investigate whether reduced plasma apoM concentrations are causally linked to increased risk of type 2 diabetes.

DESIGN

Prospective study design analyzed by Mendelian randomization.

SETTING AND PARTICIPANTS

Two cohorts reflecting the Danish general population: the Copenhagen City Heart Study (CCHS, n = 8589) and the Copenhagen General Population Study (CGPS; n = 93 857). Observational analyses included a subset of participants from the CCHS with available plasma apoM (n = 725). Genetic analyses included the complete cohorts (n = 102 446). During a median follow-up of 16 years (CCHS) and 8 years (CGPS), 563 and 2132 participants developed type 2 diabetes.

MAIN OUTCOME MEASURES

Plasma apoM concentration, genetic variants in APOM, and type 2 diabetes.

RESULTS

First, we identified an inverse correlation between plasma apoM and risk of type 2 diabetes in a subset of participants from the CCHS (hazard ratio between highest vs lowest quartile (reference) = 0.32; 95% confidence interval = 0.1-1.01; P for trend = .02). Second, genotyping of specific single nucleotide polymorphisms in APOM further revealed a 10.8% (P = 6.2 × 10-5) reduced plasma apoM concentration in participants with variant rs1266078. Third, a meta-analysis including data from 599 451 individuals showed no association between rs1266078 and risk of type 2 diabetes.

CONCLUSIONS

The present study does not appear to support a causal association between plasma apoM and risk of type 2 diabetes.

Effect of insulin on natriuretic peptide gene expression in porcine heart

Gut hormones affect cardiac function and contractility. In this study, we examined whether insulin affects the cardiac atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) gene expression and release of proANP-derived peptides in pigs. Anaesthetized pigs were included in an experimental study comparing the effect of hyperinsulinemia in 15 pigs submitted to two different protocols versus 11 control pigs receiving saline infusion. Phosphorylation of Akt on Thr308 was determined by western blotting with a pAkt-Thr308 antibody. The mRNA contents of ANP and BNP were determined with real-time PCR; plasma and cardiac tissue proANP was measured with an immunoluminometric assay targeted against the mid-region of the propeptide and a processing-independent assay. Insulin stimulation increased phosphorylation of Akt Thr308 in both left atrium and left ventricle of porcine hearts (p < 0.005). No change was observed in ANP and BNP mRNA contents in the right or left atrium. BNP mRNA contents in the left ventricle, however, decreased 3-fold (p = 0.02) compared to control animals, whereas the BNP mRNA content in the right ventricle as well as ANP mRNA content in the right and left ventricle did not change following hyperinsulinemia. Moreover, the peptide contents did not change in the four cardiac chambers. Finally, proANP concentrations in plasma did not change during the insulin infusion compared to the control animals. These results suggest that insulin does not have direct effect on atrial natriuretic peptide expression but may have a role in the left ventricle.

Aging Suppresses Sphingosine-1-Phosphate Chaperone ApoM in Circulation Resulting in Maladaptive Organ Repair

Here, we show that the liver-derived apolipoprotein M (ApoM) protects the lung and kidney from pro-fibrotic insults and that this circulating factor is attenuated in aged mice. Aged mouse hepatocytes exhibit transcriptional suppression of ApoM. This leads to reduced sphingosine-1-phosphate (S1P) signaling via the S1P receptor 1 (S1PR1) in the vascular endothelial cells of lung and kidney. Suboptimal S1PR1 angiocrine signaling causes reduced resistance to injury-induced vascular leak and leads to organ fibrosis. Plasma transfusion from Apom transgenic mice but not Apom knockout mice blocked fibrosis in the lung. Similarly, infusion of recombinant therapeutics, ApoM-Fc fusion protein enhanced kidney and lung regeneration and attenuated fibrosis in aged mouse after injury. Furthermore, we identified that aging alters Sirtuin-1-hepatic nuclear factor 4α circuit in hepatocytes to downregulate ApoM. These data reveal an integrative organ adaptation that involves circulating S1P chaperone ApoM⁺ high density lipoprotein (HDL), which signals via endothelial niche S1PR1 to spur regeneration over fibrosis.

Cardiovascular prognostic value of echocardiography and N terminal pro B-type natriuretic peptide in type 1 diabetes: the Thousand & 1 Study

AIMS

Patients with type 1 diabetes have a high risk of cardiovascular disease. Yet, the importance of routine assessment of myocardial function in patients with type 1 diabetes is not known. Thus, we examined the prognostic importance of NT-proBNP and E/e', an echocardiographic measure of diastolic function, in type 1 diabetes patients with preserved left ventricular ejection fraction (LVEF) and without known heart disease.

METHODS AND RESULTS

Type 1 diabetes patients without known heart disease and LVEF ≥45% enrolled in the Thousand and 1 study were included and followed through nationwide registries. The risk of major cardiovascular events (MACE) and death associated with levels of NT-proBNP and E/e' was examined. Of 960 patients, median follow-up of 6.3 years (Q1-Q3: 5.7-7.0), 121 (12%) experienced MACE and 51 (5%) died. Increased levels of both NT-proBNP and E/e' were associated with worse outcomes (adjusted hazard ratios for MACE = 1.56 (1.23-1.98) and 4.29 (2.25-8.16) per Loge increase for NT-proBNP and E/e', respectively). NT-proBNP and E/e' combined significantly improved the discrimination power of the Steno T1D risk engine (MACE, C-index: 0.813 (0.779-0.847) vs 0.779 (0.742-0.816); P = 0.0001; All-cause mortality, C-index 0.855 (0.806-0.903) vs 0.828 (0.776-0.880); P = 0.03).

CONCLUSION

In patients with type 1 diabetes, preserved ejection fraction, and no known heart disease, NT-proBNP and E/e' were associated with increased risk of MACE and all-cause mortality. The risks associated with NT-proBNP and E/e' combined identified patients at remarkably high risk.

Neonatal HDL Counteracts Placental Vascular Inflammation via S1P-S1PR1 Axis

Placental inflammation and dysfunction during pregnancy are associated with short- and long-term adverse outcomes for the offspring. However, the mechanisms of vascular protection at the feto-placental interface are still poorly investigated. The high-density lipoprotein (HDL) associated sphingosine-1-phosphate (S1P) has been described as a powerful anti-inflammatory complex. This study aimed to elucidate the role of cord blood-derived HDL (nHDL) in feto-placental endothelial dysfunction. Here, we report that the exposure of primary fetal placental arterial endothelial cell (fPAEC) to healthy nHDL-S1P attenuated the ability of TNFα to activate NF-κB signaling and increase the expression of pro-inflammatory markers. Moreover, the angiotensin II (AngII)-induced reactive oxygen species (ROS) production was blunted in the presence of nHDL, whereas it was preserved when the cells were preincubated with S1P receptor antagonists, suggesting that S1P accounts for the vascular protective function of nHDL at the feto-placental unit. These results highlight the importance of HDL and S1P metabolism and signaling in pregnancy pathophysiology.

Circulating cord blood HDL-S1P complex preserves the integrity of the feto-placental vasculature

Perinatal and long-term offspring morbidities are strongly dependent on the preservation of placental vascular homeostasis during pregnancy. In adults, the HDL-apoM-S1P complex protects the endothelium and maintains vascular integrity. However, the metabolism and biology of cord blood-derived HDLs (referred to as neonatal HDL, nHDL) strikingly differ from those in adults. Here, we investigate the role of neonatal HDLs in the regulation of placental vascular function. We show that nHDL is a major carrier of sphingosine-1-phosphate (S1P), which is anchored to the particle through apoM (r^s = 0.90, p < 0.0001) in the fetal circulation. Furthermore, this complex interacts with S1P receptors on the feto-placental endothelium and activates specifically extracellular signal-regulated protein kinases 1 and 2 (ERK) and phospholipase C (PLC) downstream signaling, promotes endothelial cell proliferation and calcium flux. Notably, the nHDL-S1P complex triggers actin filaments reorganization, leading to an enhancement of placental endothelial barrier function. Additionally, nHDL induces vasorelaxation of isolated placental chorionic arteries. Taken together, these results suggest that circulating nHDL exerts vasoprotective effects on the feto-placental endothelial barrier mainly via S1P signaling.

Validity of biopsy-based drug effects in a diet-induced obese mouse model of biopsy-confirmed NASH

Background

Compounds in clinical development for nonalcoholic steatohepatitis (NASH) improve liver histopathology in diet-induced obese mouse models of biopsy-confirmed NASH. Since the biopsy section used for histopathological evaluation represents only < 1% of the whole mouse liver, we evaluated how well biopsy-based quantitative image analyses correlate to stereology-based whole-liver quantitative changes upon drug treatment.

Methods

Male leptin-deficient Lep^ob/Lep^ob mice were fed the Amylin liver NASH (AMLN) diet for 16 weeks before stratification into treatment groups using a biopsy-based evaluation of type I collagen αI (col1a1) levels. Mice were treated for 8 weeks with either vehicle (PO, QD), liraglutide (0.4 mg/kg, SC, QD), elafibranor (30 mg/kg, PO, QD) or INT-767 (10 mg/kg, PO, QD). Terminal quantitative histological assessment of liver lipid (hematoxylin-eosin staining), inflammation (galectin-3 immunohistochemistry (IHC); gal-3), and fibrosis (col1a1 IHC) was performed on terminal liver biopsies and compared with stereologically sampled serial sections spanning the medial, left and right lateral lobe of the liver.

Results

The distribution of liver lipid and fibrosis was markedly consistent across lobes, whereas inflammation showed some variability. While INT-767 and liraglutide significantly reduced total liver weight by 20 and 48%, respectively, elafibranor tended to exacerbate hepatomegaly in Lep^ob/Lep^ob-NASH mice. All three compounds markedly reduced biopsy-based relative liver lipid content. Elafibranor and INT-767 significantly reduced biopsy-based relative gal-3 levels (P < 0.001), whereas INT-767 and liraglutide tended to reduce relative col1a1 levels. When changes in liver weight was accounted for, both INT-767 and liraglutide significantly reduced biopsy-based total col1a1 content. Although minor differences in absolute and relative liver lipid, inflammation and fibrosis levels were observed across lobes, the interpretation of drug-induced effects were consistent with biopsy-based conclusions. Notably, the incorporation of changes in total liver mass revealed that liraglutide’s efficacy reached statistical significances for all analyzed parameters.

Conclusions

In conclusion, in-depth analyses of liver homogeneity demonstrated that drug-induced improvement in liver biopsy-assessed histopathology is representative for overall liver effects assessed using stereology. Importantly, these findings reveal how changes in whole-liver mass should be considered to provide a deeper understanding of apparent drug treatment efficacy in preclinical NASH studies.

Apolipoprotein M-bound sphingosine-1-phosphate regulates blood-brain barrier paracellular permeability and transcytosis

The blood-brain barrier (BBB) is formed by the endothelial cells lining cerebral microvessels, but how blood-borne signaling molecules influence permeability is incompletely understood. We here examined how the apolipoprotein M (apoM)-bound sphingosine 1-phosphate (S1P) signaling pathway affects the BBB in different categories of cerebral microvessels using ApoM deficient mice (Apom-/-). We used two-photon microscopy to monitor BBB permeability of sodium fluorescein (376 Da), Alexa Fluor (643 Da), and fluorescent albumin (45 kDA). We show that BBB permeability to small molecules increases in Apom-/- mice. Vesicle-mediated transfer of albumin in arterioles increased 3 to 10-fold in Apom-/- mice, whereas transcytosis in capillaries and venules remained unchanged. The S1P receptor 1 agonist SEW2871 rapidly normalized paracellular BBB permeability in Apom-/- mice, and inhibited transcytosis in penetrating arterioles, but not in pial arterioles. Thus, apoM-bound S1P maintains low paracellular BBB permeability in all cerebral microvessels and low levels of vesicle-mediated transport in penetrating arterioles.

Long-Acting Neurotensin Synergizes With Liraglutide to Reverse Obesity Through a Melanocortin-Dependent Pathway

Neurotensin (NT), a gut hormone and neuropeptide, increases in circulation after bariatric surgery in rodents and humans and inhibits food intake in mice. However, its potential to treat obesity and the subsequent metabolic dysfunctions have been difficult to assess owing to its short half-life in vivo. Here, we demonstrate that a long-acting, pegylated analog of the NT peptide (P-NT) reduces food intake, body weight, and adiposity in diet-induced obese mice when administered once daily for 6 days. Strikingly, when P-NT was combined with the glucagon-like peptide 1 mimetic liraglutide, the two peptides synergized to reduce food intake and body weight relative to each monotherapy, without inducing a taste aversion. Further, P-NT and liraglutide coadministration improved glycemia and reduced steatohepatitis. Finally, we show that the melanocortin pathway is central for P-NT-induced anorexia and necessary for the full synergistic effect of P-NT and liraglutide combination therapy. Overall, our data suggest that P-NT and liraglutide combination therapy could be an enhanced treatment for obesity with improved tolerability compared with liraglutide monotherapy.

Apolipoprotein M/sphingosine-1-phosphate: novel effects on lipids, inflammation and kidney biology

PURPOSE OF REVIEW

In 2011, the crystal structure of apolipoprotein M (apoM) and its capacity to bind sphingosine-1-phosphate (S1P) was characterized. Since then, a variety of studies has increased our knowledge on apoM biology and functionality. From being an unknown and hardly significant player in overall metabolism, apoM has gained significant interest.

RECENT FINDINGS

Key discoveries in the last 2 years have indicated that the apoM/S1P complex has important roles in lipid metabolism (affecting triglyceride turnover), inflammation (a marker of severe sepsis and potentially providing anti-inflammatory signaling) and kidney biology (potential to protect against immunoglobulin A nephropathy).

SUMMARY

Several studies suggest a potential for apoM/S1P as biomarkers for inflammation, sepsis and nephropathy. Also, a novel chaperone is characterized and could have potential as a drug for treatment in inflammation and nephropathy.

Effect of menopause and exercise training on plasma apolipoprotein M and sphingosine-1-phosphate

The axis of apolipoprotein M (apoM) and sphingosine-1-phosphate (S1P) is of importance to plasma lipid levels, endothelial function, and development of atherosclerosis. Menopause is accompanied by dyslipidemia and an increased risk of atherosclerosis, which can be lowered by exercise training. The aim of this study was to explore if effects of menopause and training are paralleled by changes in the apoM/S1P axis. Healthy, late premenopausal [ n = 38, age 49.2 (SD 2)] and recent postmenopausal [ n = 37, age 53.3 (SD 3)] women from the Copenhagen Women Study participated in a 3-mo, aerobic high-intensity exercise intervention. Before training, plasma apoM was higher in postmenopausal [1.08 µmol/l (SD 0.2)] compared with premenopausal [0.82 µmol/l (SD 0.2)] women ( P < 0.0001). Plasma S1P was similar in the two groups [0.44 µmol/l (SD 0.1) and 0.46 µmol/l (SD 0.1), respectively]. Thus, the pretraining S1P/apoM ratio was 26% lower in postmenopausal than premenopausal women ( P < 0.0001). After the training program, plasma apoM increased from 0.82 µmol/l (SD 0.2) to 0.90 µmol/l (SD 0.3) in premenopausal women and from 1.08 µmol/l (SD 0.2) to 1.16 µmol/l (SD 0.3) in postmenopausal women ( P < 0.05). Plasma S1P increased from 0.44 µmol/l (SD 0.1) to 0.47 µmol/l (SD 0.1) in premenopausal women and from 0.46 µmol/l (SD 0.1) to 0.48 µmol/l (SD 0.1) in postmenopausal women ( P < 0.05). The results suggest that menopause is accompanied by higher plasma apoM but not S1P concentrations and that exercise training increases plasma apoM and S1P in healthy middle-aged women irrespective of menopausal status.

NEW & NOTEWORTHY The apolipoprotein M/sphingosine-1-phosphate (apoM/S1P) complex is involved in maintaining a healthy endothelial barrier function. Our study is the first, to our knowledge, to show how menopause affects the apoM/S1P axis. The results suggest that menopause is accompanied by higher plasma apoM but not S1P concentrations. Second, to our knowledge the study is also the first to show that exercise training increases both apoM/S1P in women irrespective of menopausal status.