Lysed Erythrocyte Membranes Promote Vascular Calcification

BACKGROUND

Intraplaque hemorrhage promotes atherosclerosis progression, and erythrocytes may contribute to this process. In this study we examined the effects of red blood cells on smooth muscle cell mineralization and vascular calcification and the possible mechanisms involved.

METHODS

Erythrocytes were isolated from human and murine whole blood. Intact and lysed erythrocytes and their membrane fraction or specific erythrocyte components were examined in vitro using diverse calcification assays, ex vivo by using the murine aortic ring calcification model, and in vivo after murine erythrocyte membrane injection into neointimal lesions of hypercholesterolemic apolipoprotein E-deficient mice. Vascular tissues (aortic valves, atherosclerotic carotid artery specimens, abdominal aortic aneurysms) were obtained from patients undergoing surgery.

RESULTS

The membrane fraction of lysed, but not intact human erythrocytes promoted mineralization of human arterial smooth muscle cells in culture, as shown by Alizarin red and van Kossa stain and increased alkaline phosphatase activity, and by increased expression of osteoblast-specific transcription factors (eg, runt-related transcription factor 2, osterix) and differentiation markers (eg, osteopontin, osteocalcin, and osterix). Erythrocyte membranes dose-dependently enhanced calcification in murine aortic rings, and extravasated CD235a-positive erythrocytes or Perl iron-positive signals colocalized with calcified areas or osteoblast-like cells in human vascular lesions. Mechanistically, the osteoinductive activity of lysed erythrocytes was localized to their membrane fraction, did not involve membrane lipids, heme, or iron, and was enhanced after removal of the nitric oxide (NO) scavenger hemoglobin. Lysed erythrocyte membranes enhanced calcification to a similar extent as the NO donor diethylenetriamine-NO, and their osteoinductive effects could be further augmented by arginase-1 inhibition (indirectly increasing NO bioavailability). However, the osteoinductive effects of erythrocyte membranes were reduced in human arterial smooth muscle cells treated with the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide or following inhibition of NO synthase or the NO receptor soluble guanylate cyclase. Erythrocytes isolated from endothelial NO synthase-deficient mice exhibited a reduced potency to promote calcification in the aortic ring assay and after injection into murine vascular lesions.

CONCLUSIONS

Our findings in cells, genetically modified mice, and human vascular specimens suggest that intraplaque hemorrhage with erythrocyte extravasation and lysis promotes osteoblastic differentiation of smooth muscle cells and vascular lesion calcification, and also support a role for erythrocyte-derived NO.

[Association between low serum magnesium levels and the extent of abdominal aortic calcification in renal transplant recipients]

Introduction: In renal transplant recipients (RTRs) vascular calcifications has been associated with an increased risk of cardiovascular as well as all-cause mortality. Recent experimental and clinical studies showed that magnesium (Mg) deficiency may be related to the progression of vascular calcification. Aim of this study was to determine the hypothetical association between Mg and vascular calcifications in RTRs. Methods: Seventy-one RTRs underwent a lateral X-ray of the lumbar spine to assess the presence of calcification of the abdominal aorta. Abdominal aortic calcium (AAC) content was graded with a score ranging from 0 to 24 points. At the same time were evaluated: carotid artery intima-media thickness (IMT); left ventricular mass index (LVMi); sCa, sPO4, sMg, uMg, PTH, HDL, LDL, blood pressure (BP). Results: AAC was correlated with: age (r=0.601; P<0.001), dialysis vintage (r=0.314; P<0.01), sMg (r=-0.438; P<0.001), PTH (r=0.322; P<0.01), SBP (r=0.539; P<0.001), IMT (r=0.706; P<0.001), LVMi (r=0.326; P<0.01). Serum Mg was correlated with PTH (r= -0.304; P<0.01). IMT was correlated with LVMi and SBP (r=0.330, P<0.01; r=0.494, P <0.0001; respectively). Stepwise multiple regression analysis showed that the final model contained six predictor variables for AAC (IMT, sMg, age, SBP, proteinuria, and dialysis vintage; F5,64=31.7, P<0.001; Adjusted R2 =0.718). Patients in higher AAC thirtile (8-24) were older, with longer dialysis vintage, lower sMg, higher PTH, and higher IMT values. Conclusions: Our results suggest a hypothetical interrelationship between sMg and ACC, and IMT in RTRs.

Aortic Calcification and Arterial Stiffness Burden in a Chronic Kidney Disease Cohort with High Cardiovascular Risk: Baseline Characteristics of the Impact of Phosphate Reduction On Vascular End-Points in Chronic Kidney Disease Trial

Chronic kidney disease (CKD) is associated with excess cardiovascular morbidity and mortality compared to the general population. Hyperphosphataemia, associated with vascular calcification and arterial stiffness, may play a key role in the pathogenesis of cardiovascular disease (CVD) associated with CKD, although phosphate reduction strategies have not consistently proven to beneficially affect clinically relevant outcomes. The IMpact of Phosphate Reduction On Vascular End-points in CKD (IMPROVE-CKD) study is an international, multi-centre, randomized, placebo-controlled trial investigating the effect of the phosphate binder lanthanum carbonate on intermediate cardiovascular markers in patients with stage 3b-4 CKD. The primary end-point is change in carotid-femoral pulse wave velocity (PWV, SphygmoCor) after 96 weeks. Secondary outcomes include change in abdominal aortic calcification (AAC, computed tomography), serum phosphate and fibroblast growth factor 23 (FGF-23). In total, 278 participants were recruited and randomized, mean age 63 ± 13 years, 69% male, 45% diabetes, 32% CVD, 33% stage 3b CKD and 67% stage 4 CKD. Mean estimated glomerular filtration rate and serum phosphate were 26.6 ± 8.3 mL/min/1.72 m2 and 1.25 ± 0.20 mmol/L, respectively. Median (interquartile range) intact and c-terminal FGF-23 levels were 133.0 (89.1-202) pg/mL and 221.1 (154.3-334.1) RU/mL, respectively. Mean PWV was 10.8 ± 3.6 m/s and 81% had AAC (median Agatston score 1,535 [63-5,744] Hounsfield units). PWV ≥10 m/s was associated with older age, diabetes, CVD, presence of AAC, higher systolic blood pressure (BP), larger waist circumference and higher alkaline phosphatase. AAC was associated with older age, male sex, diabetes, CVD, higher diastolic BP, dyslipidaemia (and use of statins), smoking, larger waist circumference and increased PWV. In conclusion, IMPROVE-CKD participants had high baseline risk for cardiovascular events, as suggested by high baseline PWV and AAC values.

Association between vertebral fractures and coronary artery calcification in current and former smokers in the ECLIPSE cohort

In smokers and former smokers from the ECLIPSE cohort, there is an association between prevalent vertebral fractures (VFs) and coronary artery calcification (CAC). Chest CT scans provide the opportunity to evaluate VFs and CAC, which are potentially important comorbidities, each of which is amenable to effective interventions.

INTRODUCTION

Prevalence of VFs among smokers and patients with chronic obstructive pulmonary disease (COPD) is high, and an association between CAC and osteoporosis has been described. We investigated the associations between VFs and CAC (expressed in Agatston score) in (former) smokers.

METHODS

Current and former smokers from the ECLIPSE study (designed to determine underlying COPD progression mechanisms) were studied. Baseline Agatston score (zero (0), medium (1-400), or high (> 400)), baseline bone attenuation (BA), and prevalent and incident VFs (vertebrae T₁-L₁) were assessed on CT.

RESULTS

A total of 586 subjects were included (mean age 59.8 ± 8.3; 62.3% men; 70.1% with COPD; 21.0% with prevalent VFs; 196 with zero, 266 with medium, and 124 with high Agatston score). Of these, 23.4% suffered incident VFs within 3 years. In multivariate models, prevalent VFs were associated with medium (1.83 [95% CI 1.01-3.30]) and with high (OR = 3.06 [1.45-6.47]) Agatston score. After adjustment for BA, prevalent VFs were still associated with high (OR = 2.47 [1.13-5.40]), but not significantly with medium Agatston score (OR = 1.57 [0.85-2.88]). Similarly, after adjustment for BA, high (OR = 2.06 [1.02-4.13]) but not medium Agatston score (OR = 1.61 [0.88-2.94]) was associated with prevalent VFs. Agatston score at baseline was not associated with short-term VF incidence.

CONCLUSION

In (former) smokers, there was an association between prevalent VFs and Agatston score. Chest CT scans provide the opportunity to also evaluate for VFs and CAC, which are potentially important comorbidities, each of which is amenable to effective interventions.

Associations of cigarette smoking and burden of thoracic aortic calcification in asymptomatic individuals: A dose-response relationship

Smoking is known as a powerful predictor of pathological coronary atherosclerosis. Thoracic aortic calcification (TAC), an alternative marker for pathological atherosclerosis, has also been shown to be associated unfavorable cardiovascular outcomes. We aimed to investigate the dose-response relationship between cigarette use and calcification burden in subjects free from clinical symptoms. Among 3109 patients enrolled in this analysis, we categorized study participants according to smoking exposure pattern as: non-smokers, ex-smokers and current smokers. Smoking dose (cigarette/day), duration (years) and pack-years were semi-quantified as smoking dose exposure variables. Thoracic aortic calcification burden (including TAC score, plaque volume and plaque density) were determined and related to smoking dose and pattern information. TAC burdens (including TAC score, plaque volume and density) were highest in current smoker compared to non-smoker group, with ex-smoker showing TAC burdens in-between (all ANOVA p<0.05). Linear regression models consistently demonstrated that TAC burdens as continuous variables were independently higher in a dose-dependent manner with smoking exposure, particularly in high-dose (> 10 cigarettes/day) and the long-duration (> 3 years) smokers, even after adjusting for baseline demographic differences (all p<0.05). By logistic regression, subjects who never smoke consistently demonstrated reduced risk of TAC existence (adjusted OR: 0.65 [95% CI: 0.48–0.86], P = 0.003) in contrary to those current smokers (adjusted OR: 1.47 [95% CI: 1.10–1.89], P = 0.009). A dose-response relationship between active cigarette use and TAC burden was observed, with those who never exposed to smoking or quitted demonstrating partial protective effects. Our data provided imaging-based evidence about the potential deleterious biological hazards of long-term and high-dose cigarette consumption.

Citric-acid dialysate improves the calcification propensity of hemodialysis patients: A multicenter prospective randomized cross-over trial

Introduction

The concentration of dialysate calcium (dCa) has been suggested to affect vascular calcification, but evidence is scarce. Calcification propensity reflects the intrinsic capacity of serum to prevent calcium and phosphate to precipitate.

The use of citric-acid dialysate may have a beneficial effect on the calcification propensity due to the chelating effect on calcium and magnesium. The aim of this study was to compare the intradialytic and short-term effects of haemodialysis with either standard acetic-acid dialysate with dCa1.50 (A1.5) or dCa1.25 (A1.25), as well as citric-acid dialysate with dCa1.50 (C1.5) in bicarbonate dialysis on the calcification propensity of serum.

Methods

Chronic stable hemodialysis patients were included. This multicenter randomized cross-over study consisted out of a baseline week (A1.5), followed by the randomized sequence of A1.25 or C1.5 for one week after which the alternate treatment was provided after a washout week with A1.5. Calcification propensity of serum was assessed by time-resolved nephelometry where the T₅₀ reflects the transition time between formation of primary and secondary calciprotein particles.

Results

Eighteen patients (median age 70 years) completed the study. Intradialytic change in T₅₀ was increased with C1.5 (121 [90–152]min) compared to A1.25 (83 [43–108]min, p<0.001) and A1.5 (66 [18–102]min, p<0.001). During the treatment week, predialysis T₅₀ increased significantly from the first to the third session with C1.5 (271 [234–291] to 280 [262–339]min, p = 0.002) and with A1.25 (274 [213–308] to 307 [256–337]min, p<0.001), but not with A1.5 (284 [235–346] to 300 [247–335]min, p = 0.33).

Conclusion

Calcification propensity, as measured by the change in T₅₀, improved significantly during treatment in C1.5 compared to A1.25 and A1.5. Long-term studies are needed to investigate the effects of different dialysate compositions concentrations on vascular calcification and bone mineral disorders.

Parathyroidectomy Influences Coronary Artery Calcium Score in Asymptomatic Hemodialysis Patients with Secondary Hyperparathyroidism

BACKGROUND

Successful parathyroidectomy (PTX) with stable postoperative parathyroid hormone (PTH) levels is associated with the stabilization of coronary artery calcification score (CACS) in patients with severe secondary hyperparathyroidism (SHPT) undergoing hemodialysis. To use computed tomography (CT) to evaluate the influence of PTX on CACS in asymptomatic patients.

METHODS

This study was performed with institutional review board approval. Written consent was obtained from each patient. Forty-eight patients (mean age ± SD 54.50 ± 13.14 years; range 33-77 years) undergoing maintenance hemodialysis who underwent PTX and 56 patients (mean age 55.28 ± 12.32 years; range 35-76 years) who did not undergo PTX received prospective follow-up for 2 years. CACS was quantitatively performed using the Agatston method after CT scan. The differences between baseline and end-of-study PTX parameters were analyzed with the paired Student t test.

RESULTS

For patients who underwent PTX, mean square root of CACS did not increase from 23.16 ± 18.58 to 23.68 ± 18.16 (t = 1.846, p = 0.072) from baseline to follow-up. In patients who did not undergo PTX, mean square root of CACS increased from 20.21 ± 16.47 to 28.72 ± 20.95 (t = 10.110, p < 0.001) from baseline to follow-up. In addition, the median annual progression rate of CACS was lower among PTX patients (4.89%), compared with the marked annual progression rate of CACS in non-PTX patients (52.81%; t = 11.264, p < 0.001).

CONCLUSION

Dysregulation of calcium and phosphate metabolism caused by SHPT may result in significant CAC progression in asymptomatic hemodialysis patients. Low PTH state after PTX may stabilize CAC progression in hemodialysis patients.

The relationship between aortic calcification and anastomotic leak following gastrointestinal resection: A systematic review

BACKGROUND

Anastomotic leak (AL) is a significant complication of gastrointestinal (GI) surgery. Impaired perfusion of the anastomosis is thought to play an important role. The degree of aortic calcification (AC) visible on preoperative CT imaging may be associated with an increased risk of AL following GI resection. This review assessed the relationship between AC and AL in patients undergoing GI resection.

MATERIALS AND METHODS

MEDLINE, EMBASE and the Cochrane library were systematically searched between 1946 and 2019. Relevant keywords were grouped to form a sensitive search strategy: surgical procedure (e.g. digestive system surgical procedure), calcification (e.g. vascular calcification, calcium score) and outcome (e.g. anastomotic leak). Studies assessing the degree of AC on preoperative imaging in relation to AL in adult patients requiring resection and anastomosis were included. The quality of each study was assessed using the Newcastle-Ottawa scale. Bias was assessed using the RevMan risk of bias tool.

RESULTS

Nine observational studies were included: four in patients undergoing oesophageal resection (n = 1446) and five in patients undergoing colorectal resection (n = 556). AL occurred in 20% of patients following oesophagectomy and 14% of patients following colorectal resection. Adjustment for relevant confounders was limited in most studies. Two studies reported a relationship between the degree of AC and AL in patients undergoing oesophagectomy, independent of age and comorbidity. One study reported an association between AC and AL following colorectal resection, while three studies reported higher calcium scores in the iliac arteries of patients who developed colorectal AL. Overall study quality was moderate to good using the Newcastle-Ottawa scale. Detection and reporting bias was evident in the studies examining AL following colorectal resection.

CONCLUSION

The current evidence suggests that the degree of AC may be associated with the development of AL, in particular in patients undergoing oesophagectomy. Further prospective data with adequate adjustment for confounders are required.

PROSPERO REGISTRATION NUMBER

CRD42018081128.

The Value of Imaging of the Parathyroid Glands in Secondary Hyperparathyroidism

It is estimated that up to 90% of patients with chronic kidney disease develop secondary hyperparathyroidism (sHPT). Although the disease has multiple manifestations, the most important pathological feature, from the point of view of increased mortality, is represented by the ectopic arterial, myocardial and cardiac valvular calcifications. The calcifications are progressive and lead to high blood pressure, left ventricular hypertrophy, atrio-ventricular blocks, angina and myocardial infarction. Therefore the risk of cardio-vascular events is increased. Failure of drug therapy to control disease progression is an indication for parathyroidectomy. In sHPT all parathyroid glands are affected, hence the need to detect 4 glands intraoperatively, by bilateral cervical exploration. However, considering the possibility of ectopic localization of these glands as well as the possibility of some supernumerary glands, it is desirable to have an imagistic map as accurate as possible, thus avoiding the risk of postoperative recurrence. The available imaging investigations are represented by the ultrasound of the cervical region, the parathyroid scintigraphy and those of the second line - CT or MRI examination. If in primary hyperparathyroidism, where there is only one parathyroid adenoma (or two), the preoperative imaging results are satisfactory, in sHPT there are many cases in which the imaging does not reveal all four parathyroid glands.

FGF23 and Phosphate-Cardiovascular Toxins in CKD

Elevated levels of fibroblast growth factor 23 (FGF23) and phosphate are highly associated with increased cardiovascular disease and mortality in patients suffering from chronic kidney disease (CKD). As the kidney function declines, serum phosphate levels rise and subsequently induce the secretion of the phosphaturic hormone FGF23. In early stages of CKD, FGF23 prevents the increase of serum phosphate levels and thereby attenuates phosphate-induced vascular calcification, whereas in end-stage kidney disease, FGF23 fails to maintain phosphate homeostasis. Both hyperphosphatemia and elevated FGF23 levels promote the development of hypertension, vascular calcification, and left ventricular hypertrophy by distinct mechanisms. Therefore, FGF23 and phosphate are considered promising therapeutic targets to improve the cardiovascular outcome in CKD patients. Previous therapeutic strategies are based on dietary and pharmacological reduction of serum phosphate, and consequently FGF23 levels. However, clinical trials proving the effects on the cardiovascular outcome are lacking. Recent publications provide evidence for new promising therapeutic interventions, such as magnesium supplementation and direct targeting of phosphate and FGF receptors to prevent toxicity of FGF23 and hyperphosphatemia in CKD patients.

The effect of vitamin K2 supplementation on vascular calcification in haemodialysis patients: a 1-year follow-up randomized trial

PURPOSE

Vascular calcification (VC) is an independent risk factor for cardiovascular disease in hemodialysis patients while Matrix GLA protein (MGP) is one of the most potent inhibitors of VC and its activation is vitamin K dependent. The aim of this study is to investigate the role of oral vitamin K2 supplementation in the prevention of VC progression in haemodialysis patients.

METHODS

We conducted a prospective randomized interventional study in patients on hemodialysis. Patients were randomly assigned to either receiving orally 200 μgr of vitamin K2 (vitamin K2/MK-7, Solgar) every day for 1 year or no treatment. Uncarboxylated MGP (uc-MGP) concentrations were quantified using ELISA at randomization, at 3 and at 12 months. Aortic calcification was evaluated using Agatston score after an abdominal computed tomography scan that was performed at the beginning and at 12 months of follow-up.

RESULTS

There were 102 patients that were randomized. After 1 year of follow-up, 22 patients from the vitamin K2 group and 30 patients from the control group were included in the analysis. After 3 months of treatment, uc-MGP values remained unchanged in the vitK2 group but after 1 year were reduced by 47% (p = 0.005). Furthermore, uc-MGP at 1 year was increased by 12% in the control group. At 1 year, vitK2 group had significantly lower values of uc-MGP in comparison to controls (p = 0.03). Agatston score was increased significantly both in vitamin K2 and control group at 1 year with no difference between groups.

CONCLUSIONS

Oral administration of vitamin K2 in patients on haemodialysis reduced serum uc-MGP levels but did not have an effect in the progression of aortic calcification.

Mechanisms of Vascular Calcification in Kidney Disease

The increase in prevalence and severity of vascular calcification in chronic kidney disease is a result of complex interactions between changes in the vascular bed, mineral metabolites, and other uremic factors. Vascular calcification can occur in the intima and the media of arterial wall. Under permissive conditions, vascular smooth muscle cells (VSMCs) can transform to osteoblast-like phenotype. The membrane-bound vesicles released from transformed VSMCs and the apoptotic bodies derived from dying VSMCs serve as nucleating structures for calcium crystal formation. Alterations in the quality and the quantity of endogenous calcification inhibitors also give rise to an environment that potentiates calcification.

Relationship of matrix Gla protein and vitamin K with vascular calcification in hemodialysis patients

Objective: This study evaluated associations of serum matrix Gla protein (MGP), plasma vitamin K1, and plasma vitamin K2 with coronary artery calcium score (CACS) and cardiovascular disease (CVD) in maintenance hemodialysis (MHD) patients. Methods: Subjects comprised 112 MHD patients aged 30-60 years and 40 age-matched healthy subjects. Total MGP, vitamin K1, vitamin K2, and lipid profile were examined in all subjects; other clinical data, medication use, and CACS were assessed only in MHD patients. Determinants of MGP in all subjects were identified by regression analysis. Factors associated with CACS and CVD in MHD patients were identified by regression analysis and logistic analysis, respectively. Results: Lower plasma levels of vitamin K1 corrected for triglycerides [0.39 (0.24-0.70) vs. 0.77 (0.48-1.34) ng/mg, p < 0.001], higher frequency of plasma vitamin K2 ≤ 0.05 ng/ml (p = 0.23), and higher serum total MGP (288.4 ± 44.2 vs. 159.7 ± 40.6 ng/ml, p < 0.0001) were observed in MHD patients than in healthy controls. Total MGP level was significantly associated with levels of vitamin K1 corrected for triglycerides (p <0 .001) and vitamin K2 ≤ 0.05 ng/ml (p < 0.05) in all subjects. Total MGP level was significantly associated with presence of CVD (p <0 .05), but not CACS, in MHD patients. Conclusion: The end-stage renal disease on hemodialysis is a deficiency state of vitamin K. Total MGP was significantly higher in MHD patients compared to healthy subjects and total MGP was associated with the presence of CVD, but not CACS, in MHD patients.

Risk factors associated with coronary artery calcification in midlife women: a population-based study

The aim of this study was to investigate the association between individual risk factors and coronary artery calcification (CAC), as a marker of subclinical cardiovascular disease, in a population-based nested cross-sectional study of midlife women. Anthropometric and metabolic data from 295 women from the South of Brazil were analyzed. Habitual physical activity was assessed by pedometer. CAC was assessed by a multi-detector computed tomography system. Average Agatston score was used to stratify participants as CAC > 0 and CAC = 0. Women with CAC > 0 (34.7%) were older (58.7 ± 5.4 vs. 56.3 ± 5.2 years, p < .001) and had higher prevalence of central adiposity (71 vs. 59%, p = .04) and hypertension (71 vs. 52%, p = .002) than women in the CAC = 0 group. Hormone therapy (HT) was more prevalent in the group with CAC = 0 (19.7 vs. 9.8%, p = .029). The prevalence ratios for CAC > 0 were 0.545 (95%CI:0.309-0.962, p = .036) for HT and 1.752 (95%CI:1.207-2.541, p = .003) for hypertension, after adjustment for age, educational level, smoking, alcohol intake, and physical activity. The present data in a population-based sample of midlife women indicate that hypertension and age were positively associated with higher risk for CAC > 0 and HT was related with CAC = 0.

The association between progression of coronary artery calcium and colorectal adenoma: A retrospective follow-up study of asymptomatic Koreans

The potential relationship between coronary artery calcium (CAC) and colorectal adenoma has been widely indicated. This study aimed to investigate the relationship between the risk of colorectal adenoma and CAC progression in asymptomatic Korean adults who underwent serial assessments by colonoscopy and CAC scan.A total of 754 asymptomatic participants, who had undergone serial CAC scans and colonoscopies for screening, were enrolled. Changes in CAC were assessed according to the absolute change between baseline and follow-up results. CAC progression was defined using Multi-Ethnic Study of Atherosclerosis method. Risk for adenoma at follow-up colonoscopy was determined using hazard ratio (HR) by Cox regression. The area under the receiver operating characteristic (ROC) curve was measured.The mean follow-up duration was 3.4 ± 2.5 years. CAC progression was found in 215 participants (28.5%). Participants with adenoma at index colonoscopy showed a higher rate of CAC progression than those without (38.8% vs 23.6%, P < .01). In participants with adenoma at index colonoscopy, CAC progression significantly increased the cumulative risk for adenoma at follow-up colonoscopy (HR = 1.48, 95% confidence interval [CI] 1.06-2.06, log-rank P = .021). In multivariate analysis, male sex (HR = 2.57, 95% CI 1.22-5.42, P = .013), ≥3 adenomas at index colonoscopy (HR = 2.60, 95% CI 1.16-5.85, P = .021), and CAC progression (HR = 2.74, 95% CI 1.48-5.08, P = .001) increased the risk of adenoma at follow-up colonoscopy. In participants without adenoma at index colonoscopy, neither baseline CAC presence nor CAC progression increased the risk of adenoma at follow-up colonoscopy. The interaction between CAC progression and adenoma at index colonoscopy was significant in multivariable model (P = .005). In the ROC analysis, AUC of CAC progression for adenoma at follow-up colonoscopy was 0.625 (95% CI 0.567-0.684, P < .001) in participants with adenoma at index colonoscopy.Participants with CAC progression, who are at high risk of coronary atherosclerosis, may need to be considered for follow-up evaluation of colorectal adenoma, especially those with adenoma at index colonoscopy.

Bone mass density and bone metabolism marker are associated with progression of carotid and cardiac calcified plaque in Chinese elderly population

Osteoporosis and cardiovascular diseases often coexist in the same elderly individuals. Does this suggest some potential correlation between the two diseases? Low bone mass and change of bone biomarker are associated with a higher risk of carotid and cardiac calcification plaques.

INTRODUCTION

Bone mineral density (BMD) and bone metabolism marker may contribute to the progression of carotid and cardiac arterial calcifications. The aim of this study was to investigate whether low bone mass and the change of bone biomarker are associated with the prevalence of calcified atherosclerotic plaque in elderly Chinese.

METHODS

We conducted a five-year prospective study. BMD was measured by dual-energy X-ray absorptiometry scanning. Carotid and cardiac computed tomography angiography (CTA) was conducted using a 64-multidetector row scanner to assess carotid and cardiac arterial plaque at baseline and during follow-up.

RESULTS

Of 1571 community residents over 60 years of age, 184 (11.7%) subjects developed carotid calcified plaque, 510 (32.5%) subjects developed cardiac calcified plaque and 97 (6.2%) subjects developed co-existence calcified plaques in carotid and cardiac arteries. After adjustment for age and all relevant confounders, Q1, Q2 quartile of BMD, and osteoprotegerin (OPG), osteocalcin (OC), and C-terminal cross-linked telopeptide of type I collagen (CTX) were associated with increased risk of calcified plaques.

CONCLUSION

This study suggested that lower BMD and change of bone metabolism biomarker were associated with a higher risk of carotid and cardiac calcified plaque development.

The Role of Osteoprotegerin in Vascular Calcification and Bone Metabolism: The Basis for Developing New Therapeutics

Osteoporosis (OP) and cardiovascular diseases (CVD) are both important causes of mortality and morbidity in aging patients. There are common mechanisms underlying the regulation of bone remodeling and the development of smooth muscle calcification; a temporal relationship exists between osteoporosis and the imbalance of mineral metabolism in the vessels. Vascular calcification appears regulated by mechanisms that include both inductive and inhibitory processes. Multiple factors are implicated in both bone and vascular metabolism. Among these factors, the superfamily of tumor necrosis factor (TNF) receptors including osteoprotegerin (OPG) and its ligands has been established. OPG is a soluble decoy receptor for receptor activator of nuclear factor-kB ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL). OPG binds to RANKL and TRAIL, and inhibits the association with their receptors, which have been labeled as the receptor activator of NF-kB (RANK). Sustained release of OPG from vascular endothelial cells (ECs) has been demonstrated in response to inflammatory proteins and cytokines, suggesting that OPG/RANKL/RANK system plays a modulatory role in vascular injury and inflammation. For the development of potential therapeutic strategies targeting vascular calcification, critical consideration of the implications for bone metabolism must be taken into account to prevent potentially detrimental effects to bone metabolism.

Impact of C-reactive protein on osteo-/chondrogenic transdifferentiation and calcification of vascular smooth muscle cells

Medial vascular calcification occurs during the aging process and is strongly accelerated by chronic kidney disease (CKD). Elevated C-reactive protein (CRP) levels are associated with vascular calcification, cardiovascular events and mortality in CKD patients. CRP is an important promoter of vascular inflammation. Inflammatory processes are critically involved in initiation and progression of vascular calcification. Thus, the present study explored a possible impact of CRP on vascular calcification. We found that CRP promoted osteo-/chondrogenic transdifferentiation and aggravated phosphate-induced osteo-/chondrogenic transdifferentiation and calcification of primary human aortic smooth muscle cells (HAoSMCs). These effects were paralleled by increased cellular oxidative stress and corresponding pro-calcific downstream-signaling. Antioxidants or p38 MAPK inhibition suppressed CRP-induced osteo-/chondrogenic signaling and mineralization. Furthermore, silencing of Fc fragment of IgG receptor IIa (FCGR2A) blunted the pro-calcific effects of CRP. Vascular CRP expression was increased in the klotho-hypomorphic mouse model of aging as well as in HAoSMCs during calcifying conditions. In conclusion, CRP augments osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells through mechanisms involving FCGR2A-dependent induction of oxidative stress. Thus, systemic inflammation may actively contribute to the progression of vascular calcification.

Circulating microRNAs and vascular calcification in hemodialysis patients

Objective

Vascular calcification is common in chronic dialysis patients and is associated with increased morbidity and mortality. However, the role of circulating microRNAs (miRs) in vascular calcification has rarely been investigated. We aimed to determine circulating levels of miRs in hemodialysis patients, and analyzed their relationship with vascular calcification.

Methods

Sixty-one stable hemodialysis patients were enrolled, including 31 with vascular calcification and 30 without. Demographic and biochemical data were collected and reviewed. The presence and severity of vascular calcification were determined by lumber spine X-ray. Blood levels of miR29a/b, miR223, miR9, and miR21 were determined.

Results

Patients with vascular calcification were older (65.6 ± 9.0 vs. 59.1 ± 7.1 years) with a higher proportion of vascular disease (55% vs. 23%) than those without vascular calcification. Additionally, high-sensitivity C-reactive protein (3.90 vs 2.09 mg/dL) and fibroblast growth factor 23 (17311 vs. 6306 pg/mL) were significantly higher. Patients with vascular calcification also had higher levels of miR29a/b and miR223. Regression analysis indicated that age and miR29a were significant associates of the calcification score.

Conclusions

Hemodialysis patients with vascular calcification had higher levels of miR 29a/b and miR223 than those without vascular calcification, and circulating miR29a was associated with calcification severity.

Metabolism, Obesity, and Diabetes Mellitus

Obesity and diabetes remain leading causes of reduced health span and life span throughout the world. Hence, it is not surprising that these areas are at the center of highly active areas of research. The identification of novel mechanisms underlying these metabolic disorders sets the stage for uncovering new potential therapeutic strategies. In this issue of Highlights in Arteriosclerosis, Thrombosis and Vascular Biology, we review recently published papers in the journal that add to our understanding of causes and consequences of obesity and diabetes and how these disorders impact metabolic function. Collectively, these studies in cultured cells to in vivo animal models to human subjects add to the growing body of evidence that both cell-intrinsic and cell-cell communication mechanisms collaborate in metabolic disorders to cause obesity, insulin resistance and diabetes and its complications.

Volumes of coronary plaque disease in relation to body mass index, waist circumference, truncal fat mass and epicardial adipose tissue in patients with type 2 diabetes mellitus and controls

OBJECTIVES

Coronary atherosclerosis in patients with type 2 diabetes mellitus may be promoted by regional fat distribution. We investigated the association between anthropometric measures of obesity, truncal fat mass, epicardial adipose tissue and coronary atherosclerosis in asymptomatic patients and matched controls.

METHODS

We examined 44 patients and 59 controls [mean (standard deviation) age 64.4 ± 9.9 vs 61.8 ± 9.7, male 50% vs 47%, diabetes duration mean (standard deviation) 7.7 ± 1.5] with coronary computed tomography angiography. Coronary plaques were quantified as total, calcified, non-calcified and low-density non-calcified plaque volumes (mm³). Regional fat distribution was assessed by dual-energy X-ray absorptiometry, body mass index (kg/m²), waist circumference (cm) and epicardial fat volume (mm³). Endothelial function and systemic inflammation were evaluated by peripheral arterial tonometry (log transformed Reactive Hyperemia Index) and C-reactive protein (mg/L).

RESULTS

Body mass index and waist circumference (p < 0.02) were associated with coronary plaque volumes. Body mass index was associated with low-density non-calcified plaque volume after adjustment for age, sex and diabetes status (p < 0.01). Truncal fat mass (p > 0.51), waist circumference (p > 0.06) and epicardial adipose tissue (p > 0.17) were not associated with coronary plaque volumes in adjusted analyses.

CONCLUSION

Body mass index is associated with coronary plaque volumes in diabetic as well as non-diabetic individuals.

Association of Estimated Long-term Exposure to Air Pollution and Traffic Proximity With a Marker for Coronary Atherosclerosis in a Nationwide Study in China

IMPORTANCE

Epidemiologic evidence of the mechanisms of the association between long-term exposure to air pollution and coronary heart disease (CHD) is limited and relies heavily on studies performed in Europe and the United States, where air pollution levels are relatively low. In particular, the association between air pollution and CHD in patients with underlying risks for CHD is understudied.

OBJECTIVE

To determine whether air pollution and proximity to traffic are associated with the coronary artery calcium (CAC) score, a key atherosclerotic marker.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective, population-based cross-sectional study in a large-scale setting in China, 8867 consecutive patients aged 25 to 92 years with suspected CHD were recruited between November 17, 2015, and September 13, 2017. Participants were excluded if they had previous myocardial infarction, stenting, or coronary artery bypass grafting or incomplete risk factors and exposure data. Each participant underwent assessment of CAC and CHD risk factors at baseline. Data were analyzed from December 2017 to November 2018.

EXPOSURES

Annual means of fine particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) were estimated at the participants' residences using a validated geostatistical prediction model. Exposure to a nearby roadway was also estimated.

MAIN OUTCOMES AND MEASURES

Computed tomography measurement of CAC score.

RESULTS

The mean (SD) age of the 8867 participants was 56.9 (10.4) years; 4378 (53.6%) were men. Annual mean (SD) PM2.5, NO2, and O3 measurements were 70.1 (20.0), 41.4 (14.7), and 93.9 (10.5) μg/m3, respectively. The mean (SD) CAC score was 91.4 (322.2) Agatston units. Exposure to PM2.5 and NO2, adjusting for CHD risk factors and multiple pollutants, were independently associated with increases in CAC scores of 27.2% (95% CI, 10.8% to 46.1%) per 30 μg/m3 PM2.5 and 24.5% (95% CI, 3.6% to 49.7%) per 20 μg/m3 NO2. For PM2.5, odds of both detectable CAC (Agatston score >0; odds ratio, 1.28; 95% CI, 1.13 to 1.45) and severe CAC (Agatston score >400; odds ratio, 1.59; 95% CI, 1.20 to 2.12) were increased. Associations of CAC with PM2.5 and NO2 were greater among male participants (PM2.5: 42.2%; 95% CI, 24.3% to 62.7%; NO2: 45.7%; 95% CI, 25.3% to 69.5%) and elderly participants (PM2.5: 50.1%; 95% CI, 28.8% to 75.0%; NO2: 55.5%; 95% CI, 31.8% to 83.6%) and those with diabetes (PM2.5: 62.2%; 95% CI, 30.9% to 101.0%; NO2: 31.2%; 95% CI, 13.9% to 51.0%). Independent association with CAC score was 9.0% (95% CI, -1.4% to 20.4%) for O3 per 15 μg/m3 and 2.4% (95% CI, -0.6% to 5.4%) for distance near roadway per 50% decrease.

CONCLUSIONS AND RELEVANCE

In this large Chinese study, long-term exposures to PM2.5 and NO2 were independently associated with severity of CAC. This finding may provide support for the pathophysiological role of coronary atherosclerosis through which air pollution exposure may be associated with CHD.

Malnutrition, inflammation, progression of vascular calcification and survival: Inter-relationships in hemodialysis patients

Background and aims

Malnutrition and inflammation are closely linked to vascular calcification (VC), the severity of which correlate with adverse outcome. However, there were few studies on the interplay between malnutrition, inflammation and VC progression, rather than VC presence per se. We aimed to determine the relationship of malnutrition, inflammation, abdominal aortic calcification (AAC) progression with survival in hemodialysis (HD) patients.

Methods

Malnutrition and inflammation were defined as low serum albumin (< 40 g/L) and high hs-CRP (≥ 28.57 nmol/L), respectively. We defined AAC progression as an increase in AAC score using lateral lumbar radiography at both baseline and one year later. Patients were followed up to investigate the impact of AAC progression on all-cause and cardiovascular mortality.

Results

AAC progressed in 54.6% of 97 patients (mean age 58.2±11.7 years, 41.2% men) at 1-year follow-up. Hypoalbuminemia (Odds ratio 3.296; 95% confidence interval 1.178–9.222), hs-CRP (1.561; 1.038–2.348), low LDL-cholesterol (0.976; 0.955–0.996), and the presence of baseline AAC (10.136; 3.173–32.386) were significant risk factors for AAC progression. During the mean follow-up period of 5.9 years, 38(39.2%) patients died and 27(71.0%) of them died of cardiovascular disease. Multivariate Cox regression analysis adjusted for old age, diabetes, cardiovascular history, and hypoalbuminemia determined that AAC progression was an independent predictor of all-cause mortality (2.294; 1.054–4.994).

Conclusions

Malnutrition and inflammation were significantly associated with AAC progression. AAC progression is more informative than AAC presence at a given time-point as a predictor of all-cause mortality in patients on maintenance HD.

Supplementary nutrients for prevention of vascular calcification in patients with chronic kidney disease

Vascular calcification (VC) and malnutrition associated with cardiovascular disease are common in patients with chronic kidney disease (CKD) treated with dialysis. VC, which reflects vascular aging, and malnutrition are also encountered in the non-CKD elderly population. This similarity of clinical findings suggests that the progression of CKD is related to aging and the existence of a causal relationship between VC and malnutrition. To retard renal progression, a low- or very-low-protein diet is usually recommended for CKD patients. Dietary education may induce malnutrition and deficiency of important nutrients, such as vitamins K and D. Menaquinone-7, a type of vitamin K2, is under investigation for inhibiting VC in elderly patients without CKD, as well as for prevention of VC in patients with CKD. Nutritional vitamin D, such as cholecalciferol, may be considered to decrease the required dose of active vitamin D, which increases the risk of VC due to increased calcium and phosphate loads. Omega-3 fatty acids are important nutrients and their ability to inhibit VC needs to be evaluated in clinical trials. This review focuses on the ability of supplementary nutrients to prevent VC in patients with CKD, in whom dietary restriction is essential.

The importance of fetuin-A in vascular calcification in children with chronic kidney disease

BACKGROUND

The status of the cardiovascular (CV) system in children with chronic kidney disease (CKD) is significantly influenced by increasing stiffness of the arterial wall. This largely depends on the shortage of local and systemic inhibitors of soft tissue calcification.

OBJECTIVES

The aim of the study was to evaluate the role of fetuin-A in conjunction with other factors in the progressive hardening of the vascular wall in these children. We examined serum fetuin-A concentrations in relation to renal function, dialysis modality, and other clinical and biochemical markers promoting vascular calcification.

MATERIAL AND METHODS

Twenty children on peritoneal dialysis (PD), 20 on hemodialysis (HD), 36 treated conservatively, and 26 healthy subjects were enrolled into a cross-sectional study. In all children, fetuin-A and numerous clinical and biochemical parameters were measured.

RESULTS

The fetuin-A concentration was significantly lower in children on hemodialysis (HD) vs children on peritoneal dialysis (PD), conservatively treated subjects, and the control group. In sick children, fetuinA concentration negatively correlated with dialysis vintage, PWV/ht, phosphate concentration, calcium phosphate product (CaxP), cumulative doses of calcium, and vitamin D3. In the whole study population, fetuin-A negatively correlated with blood pressure (BP), pulse wave velocity indexed to height (PWV/ht), intact parathyroid hormone (iPTH), high sensitivity C-reactive protein (hsCRP), and cholesterol concentrations.

CONCLUSIONS

In children with CKD, the decreased concentration of fetuin-A is related to other vascular calcification risk factors. Serum fetuin-A concentration may play a role in the identification of vascular disease risk factors in this population.