Cardiovascular risk in chronic kidney disease patients: intima-media thickness predicts the incidence and severity of histologically assessed medial calcification in radial arteries

Correlation between different types of obesity and hypertension in perimenopausal working women

Hypertension (HTN) can lead to a series of target organ damage and is associated with increased cardiovascular disease incidence and mortality. Perimenopause implies an important physiological transition. Previous studies have confirmed that obesity is a risk factor for the development of HTN. Nevertheless, few studies have investigated the prevalence of HTN in perimenopausal women and the relationships between peripheral or abdominal obesity and HTN. Therefore, we analysed the influencing factors of HTN in perimenopausal working women and the correlation between different types of obesity and HTN to provide evidence for the need to prevent HTN in perimenopausal women. Perimenopausal women who underwent physical examination at Shanghai Health and Medical Center from January 2021 to October 2021 were selected as subjects. A multivariate logistic regression model was used to analyse the associations between different types of obesity and HTN in perimenopausal women. Five hundred eighty-two perimenopausal women were included in this study; 124 cases of HTN were detected (incidence rate 21.31%), 23 of which were isolated systolic HTN (18.55% of total HTN cases). Multivariate logistic regression analysis revealed that age and BMI were the influencing factors of HTN in perimenopausal women. Compared with that of perimenopausal women without peripheral obesity, HTN in overweight (OR = 1.84, 95% CI: 1.13-2.98) and peripheral obesity (OR = 4.36, 95% CI: 1.52-12.54) women increased with increasing body weight. Perimenopausal women with abdominal obesity had a greater risk of developing HTN (OR = 2.69, 95% CI: 1.16-6.21) (P < 0.05). Age and BMI are risk factors for the development of HTN in perimenopausal working women. Both abdominal obesity and peripheral obesity are positively associated with HTN in perimenopausal women. The BMI and abdominal circumference of perimenopausal women need to be monitored as early as possible to prevent obesity and reduce the occurrence of HTN.

Elevated Iliac Calcium Score as a Marker of Coronary Calcification and Overall Atherosclerotic Risk

BACKGROUND

The initial assessment of cardiovascular risk in patients undergoing lower limb revascularization surgery is crucial to minimize complications and improve outcomes. This study aims to determine if the iliac calcium score (ICS) serves as a cardiologic risk marker by examining its correlation with the coronary calcium score (CCS) in these patients.

METHODS

This prospective observational single-center study included 248 patients with critical limb ischemia undergoing revascularization procedures from January 2022 to June 2023. Baseline characteristics such as age, gender, smoking status, comorbidities, and clinical status were recorded. CCS and ICS were calculated using preoperative computed tomography angiography. Multiple linear regression identified significant predictors of ICS, including CCS, iliac intima-media thickness (i-IMT), coronary artery disease, diabetes, chronic kidney disease, hypertension, dyslipidemia, and smoking.

RESULTS

The study population had a mean age of 74.4 years, 83.86% male. Significant correlations were found between ICS and CCS (Pearson r = 0.34, P < 0.001) and between ICS and i-IMT (Pearson r = 0.35, P < 0.001). Regression analysis revealed significant predictors for ICS, including CCS (coefficient = 1.808, P < 0.0001), i-IMT (coefficient = 3.11, P < 0.0001), coronary artery disease (coefficient = 11.94, P = 0.042), diabetes (coefficient = 19.59, P = 0.002), chronic kidney disease (coefficient = 11.79, P < 0.0001), and hypertension (coefficient = 22.10, P = 0.001). Dyslipidemia and smoking did not show significant associations with ICS.

CONCLUSIONS

The ICS shows a statistically significant association with the CCS and i-IMT in patients undergoing lower limb revascularization surgery. This correlation suggests that ICS reflects vascular calcification patterns like those observed in coronary arteries. Further studies are needed to explore this relationship in diverse patient populations and under varying clinical conditions.

Angiographic evaluation of coronary artery disease in diabetic patients with and without end-stage kidney disease

The objective of the present investigation was to compare the coronary angiography results in diabetic patients with and without end-stage kidney disease (ESKD). We included prolonged diabetic patients with ESKD (93 patients) and without ESKD (control group, 126 patients). Angiography of the coronary arteries was performed on all patients. Our results revealed that the ESKD patients tended to have a higher degree of coronary artery stenosis in all parts of LAD (p = 0.001, 0.024, and 0.005), proximal and distal RCA (p = 0.013, and 0.008), and proximal and distal LCX artery (p = 0.001, 0.008) than non-ESKD patients. Furthermore, we found that the ESKD group had higher significant coronary artery stenosis in the LAD artery (60.5% vs. 39.5%, p < 0.001), RCA (60.3% vs. 39.7%, p < 0.001), LCX artery (79.5% vs. 20.5%, p < 0.001), and LMCA (84.6% vs 15.4%, p = 0.002) compared to control group. There was a greater prevalence of multiple vessels coronary artery disease (≥ two) among ESKD patients (29%), compared with the non-ESKD group (16.8%, p < 0.001). Significant coronary artery stenosis was meaningfully higher in asymptomatic diabetic ESKD patients on hemodialysis than non-ESKD diabetic patients. Coronary angiography may be beneficial in diabetic patients with ESKD regardless of whether they have ischemic symptoms with low complication rate through radial access.

Targeting a Silent Disease: Vascular Calcification in Chronic Kidney Disease

Chronic kidney disease (CKD) patients have a higher risk of developing early cardiovascular disease (CVD). Although vascular calcification (VC) is one of the strongest predictors of CVD risk, its diagnosis among the CKD population remains a serious clinical challenge. This is mainly due to the complexity of VC, which results from various interconnected pathological mechanisms occurring at early stages and at multiples sites, affecting the medial and intimal layers of the vascular tree. Here, we review the most used and recently developed imaging techniques, here referred to as imaging biomarkers, for VC detection and monitoring, while discussing their strengths and limitations considering the specificities of VC in a CKD context. Although imaging biomarkers have a crucial role in the diagnosis of VC, with important insights into CVD risk, circulating biomarkers represent an added value by reflecting the molecular dynamics and mechanisms involved in VC pathophysiological pathways, opening new avenues into the early detection and targeted interventions. We propose that a combined strategy using imaging and circulating biomarkers with a role in multiple VC molecular mechanisms, such as Fetuin-A, Matrix Gla protein, Gla-rich protein and calciprotein particles, should represent high prognostic value for management of CVD risk in the CKD population.

Oxidative stress: An essential factor in the process of arteriovenous fistula failure

For more than half a century, arteriovenous fistula (AVFs) has been recognized as a lifeline for patients requiring hemodialysis (HD). With its higher long-term patency rate and lower probability of complications, AVF is strongly recommended by guidelines in different areas as the first choice for vascular access for HD patients, and its proportion of application is gradually increasing. Despite technological improvements and advances in the standards of postoperative care, many deficiencies are still encountered in the use of AVF related to its high incidence of failure due to unsuccessful maturation to adequately support HD and the development of neointimal hyperplasia (NIH), which narrows the AVF lumen. AVF failure is linked to the activation and migration of vascular cells and the remodeling of the extracellular matrix, where complex interactions between cytokines, adhesion molecules, and inflammatory mediators lead to poor adaptive remodeling. Oxidative stress also plays a vital role in AVF failure, and a growing amount of data suggest a link between AVF failure and oxidative stress. In this review, we summarize the present understanding of the pathophysiology of AVF failure. Furthermore, we focus on the relation between oxidative stress and AVF dysfunction. Finally, we discuss potential therapies for addressing AVF failure based on targeting oxidative stress.

Vascular Calcification in Chronic Kidney Disease: An Update and Perspective

Chronic kidney disease is a devastating condition resulting from irreversible loss of nephron numbers and function and leading to end-stage renal disease and mineral disorders. Vascular calcification, an ectopic deposition of calcium-phosphate salts in blood vessel walls and heart valves, is an independent risk factor of cardiovascular morbidity and mortality in chronic kidney disease. Moreover, aging and related metabolic disorders are essential risk factors for chronic kidney disease and vascular calcification. Marked progress has been recently made in understanding and treating vascular calcification in chronic kidney disease. However, there is a paucity of systematic reviews summarizing this progress, and investigating unresolved issues is warranted. In this systematic review, we aimed to overview the underlying mechanisms of vascular calcification in chronic kidney diseases and discuss the impact of chronic kidney disease on the pathophysiology of vascular calcification. Additionally, we summarized potential clinical diagnostic biomarkers and therapeutic applications for vascular calcification with chronic kidney disease. This review may offer new insights into the pathogenesis, diagnosis, and therapeutic intervention of vascular calcification.

Histopathological assessment of radial artery calcification in patients with end-stage kidney disease

Background

A comprehensive understanding of vascular calcification pathology is significant for the development of cardiovascular disease therapy in high-risk populations. This cross-sectional study aimed to evaluate the prevalence and characteristics of radial artery calcification (RAC) and to identify the factors that are associated with RAC in end-stage kidney disease (ESKD).

Methods

Detailed medical histories of 180 patients with ESKD were recorded. Fragments of the radial artery obtained during the creation of arteriovenous fistula for hemodialysis access were stained with alizarin red S.

Results

Calcification was localized in the arterial media layer. The prevalence of positive calcification staining in the radial arteries was 21.1% (n = 38). Patients with RAC had a higher glycated hemoglobin level (p < 0.01), higher prevalence of dialysis duration >5 years (p = 0.022), and diabetes mellitus (p < 0.01) than those without RAC. Multiple logistic regression models showed dialysis duration >5 years (odds ratio [OR], 9.864; 95% confidence interval [CI], 2.666–36.502; p < 0.01) and diabetes mellitus (OR, 12.689; 95% CI, 2.796–34.597; p < 0.01) were independent risk factors for RAC in patients with ESKD. Patients with dialysis duration >5 years had a higher prevalence of RAC (p = 0.012) than those with dialysis duration ≤5 years. Patients with diabetes mellitus had a higher prevalence of RAC (p < 0.01) than those without diabetes mellitus. Patients with diabetes mellitus ≥15 years had a higher prevalence of RAC (p = 0.042) than those with diabetes mellitus <15 years. Radial artery calcification level showed a significantly positive correlation with dialysis duration (p < 0.05), diabetes mellitus duration (p < 0.01), HbA1c level (p < 0.01) and Calcium level (p < 0.01).

Conclusions

In patients with ESKD, dialysis duration >5 years and diabetes predict RAC. Thus, the combination of prolonged dialysis and hyperglycemic conditions exerts a synergistic effect on RAC.

Phenotypic features of vascular calcification in chronic kidney disease

BACKGROUND

Patients with chronic kidney disease stage 5 (CKD5) are predisposed to vascular calcification (VC), but the combined effect of factors associated with VC was sparsely investigated. We applied the relaxed linear separability (RLS) feature selection model to identify features that concomitantly associate with VC in CKD5 patients.

METHODS

Epigastric arteries collected during surgery from living donor kidney transplant recipients were examined to score the histological extent of medial VC. Sixty-two phenotypic features in 152 patients were entered into RLS model to differentiate between no-minimal VC (n = 93; score 0-1) and moderate-extensive VC (n = 59; score 2-3). The subset of features associated with VC was selected on the basis of cross-validation procedure. The strength of association of the selected features with VC was expressed by the absolute value of 'RLS factor'.

RESULTS

Among 62 features, a subset of 17 features provided optimal prediction of VC with 89% of patients correctly classified into their groups. The 17 features included traditional risk factors (diabetes, age, cholesterol, BMI and male sex) and markers of bone metabolism, endothelial function, metabolites, serum antibodies and mitochondrial-derived peptide. Positive RLS factors range from 1.26 to 4.05 indicating features associated with increased risk of VC, and negative RLS factors range from -0.95 to -1.83 indicating features associated with reduced risk of VC.

CONCLUSION

The RLS model identified 17 features including novel biomarkers and traditional risk factors that together concomitantly associated with medial VC. These results may inform further investigations of factors promoting VC in CKD5 patients.

Serum fetuin-A levels and association with hematological parameters in chronic kidney disease and hemodialysis patients

Aim

The objective of the current study is to examine the association between serum fetuin-A concentrations and some other inflammation markers neutrophil to lymphocyte ratio (NLR), mean platelet volume (MPV) and C reactive protein (CRP) in patients with chronic kidney disease (CKD) and hemodialysis.

Methods

The study subjects are composed of healthy volunteers (n = 47) and two patient groups; CKD patients (n = 26) and hemodialysis patients (n = 33). We measured serum glucose, urea, creatinine, total protein, albumin, sodium, potassium, calcium, phosphorus, iron, alkaline phosphatase, parathyroid hormone, ferritin and CRP levels by auto-analyzer and fetuin-A levels by ELISA method. Also, complete blood count parameters were analyzed and NLR was calculated.

Results

There were significant differences in serum fetuin-A concentrations, NLR and MPV values among three groups (p < 0.001, p < 0.001, p < 0.001). The correlation analyses revealed that fetuin-A negatively correlated with urea, creatinine, ferritin, and CRP concentrations (r: 0.349, 0.367, 0.399, 0.550, respectively, p < 0.05).

Conclusion

Fetuin-A is lower in CKD and hemodialysis patients than the control group; supporting as a negative acute phase reactant. Determination of serum fetuin-A, NLR and MPV might be useful to assess inflammation in CKD and hemodialysis patients.

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.

Maternal obesity and gestational diabetes: Impact on arterial wall layer thickness and stiffness in early childhood - RADIEL study six-year follow-up

BACKGROUND AND AIMS

Gestational diabetes (GDM) and maternal obesity are linked to weight gain in childhood and an increased risk of cardiovascular disease later in life. We assessed the effects of GDM and maternal obesity on arterial function and morphology in relation to body anthropometrics and composition in early childhood.

METHODS

We assessed body size and composition, blood pressure (BP), arterial morphology and stiffness in 201 pairs of obese mothers (pre-pregnancy BMI 30.7 ± 5.6 kg/m², 96 with GDM) and their children at 6.1 years (SD 0.5).

RESULTS

Child BMI (z-score 0.45 ± 0.92; p < 0.001) and common carotid intima-media thickness (IMT, z-score 0.15 ± 0.75, p = 0.003) were increased compared with a healthy Finnish reference population. No associations with maternal GDM was found. Carotid IMT and pulse wave velocity were unrelated to child sex, anthropometrics, body composition, BP, as well as maternal anthropometrics and body composition. Carotid stiffness was independently predicted by second trimester fasting glucose. Child lean body mass was the strongest independent predictor for radial (RA), and brachial artery (BA) lumen diameter (LD) and BA IMT (LD: RA: r² = 0.068, p < 0.001; BA: r² = 0.108, p < 0.001; IMT: BA: r² = 0.161, p < 0.001) and carotid LD (r² = 0.066, p < 0.001).

CONCLUSIONS

Children of obese mothers have increased BMI, blood pressure and carotid IMT suggesting a transgenerational effect of maternal obesity and clustering of cardiovascular risk factors in the population. Arterial dimensions were mainly predicted by child LBM, and not associated with maternal or child adiposity, or GDM. There was a weak association with maternal gestational fasting glucose and increased carotid artery stiffness.

Factors associated with carotid intima-media thickness in patients on maintenance hemodialysis

PURPOSE

The aim of this study was to analyze the association of the carotid intima-media thickness (CIMT) with various parameters in patients on maintenance hemodialysis (mHD).

METHODS

A cross-sectional study was conducted, enrolling 68 subjects (41 men, 27 women) on mHD in the Hemodialysis Unit, Sanglah Hospital, Denpasar, Indonesia. CIMT was measured with B-mode ultrasonography using a USG Sonoace 8000 and a 7.5 MHz linear transducer.

RESULTS

CIMT was higher in subjects with cardiovascular disease (CVD) compared with those without CVD (0.6494 vs 0.7288 mm; P=0.026), and in men compared with women (0.7056 vs 0.6141 mm; P=0.003). CIMT was correlated with age (R=0.607; P<0.001), plasma albumin (R=-0.291, P=0.016), serum phosphate (R=-0.294, P=0.015), calcium-phosphate product (R=-0.284, P=0.011), and plasma high-sensitivity C-reactive protein (R=0.279, P=0.030). However, after multiple linear regression testing, only age consistently had a role in determining the CIMT value (β=0.452, P<0.001).

CONCLUSION

Subjects with CVD have higher CIMT than those without CVD and men had higher CIMT than women. In addition, older age, higher high-sensitivity C-reactive protein, and lower albumin, phosphate, and calcium-phosphate product levels were correlated with higher CIMT. Age was the most important marker for CIMT in subjects on mHD.

Serum alkaline phosphatase relates to cardiovascular risk markers in children with high calcium-phosphorus product

Although alkaline phosphatase (ALP) correlates with cardiovascular risk in adults, there are no studies in children. We evaluated the association between serum ALP levels, calcium-phosphorus product (Ca*P) and cardiovascular risk markers in healthy children. Children aged 7.9 ± 1.4 (n = 379) were recruited in this cross-sectional study. The main outcome measures were systolic and diastolic blood pressure (SBP and DBP) and carotid intima-media thickness (cIMT). Additional assessments were body-mass index (BMI), waist circumference, homeostatic model assessment of insulin resistance (HOMA-IR) and fasting lipids, ALP, serum calcium, phosphorus and Ca*P. ALP was directly correlated with BMI (p < 0.0001), waist circumference (p < 0.0001), SBP (p < 0.0001), cIMT (p = 0.005), HOMA-IR (p < 0.0001), and fasting triglycerides (p = 0.0001). Among them, in children with Ca*P values above the median the associations were BMI (r = 0.231; p = 0.001), waist (r = 0.252; p < 0.0001), SBP (r = 0.324; p < 0.0001), cIMT (r = 0.248; p = 0.001) and HOMA-IR (r = 0.291; p < 0.0001)]. ALP independently associated with SBP (β = 0.290, p < 0.001) and cIMT (β = 0.179, p = 0.013) in children with higher Ca*P, after adjusting for confounding variables. Circulating ALP is associated with a more adverse cardiovascular profile in children with higher Ca*P. We suggest that serum ALP and Ca*P levels could contribute to the assessment of risk for cardiovascular disease in children.

Serum pentraxin-3 levels and flow-mediated dilation in dipper and non-dipper hypertension

BACKGROUND

Endothelial dysfunction is one of the main pathological processes of hypertension. The association of serum pentraxin-3 (PTX3) levels and endothelial dysfunction becomes a more interesting scientific research issue due to high potential of PTX3 as a diagnostic and prognostic biomarker. We aimed to investigate the relationship between serum PTX3 levels and flow-mediated dilation results in patients with dipper and non-dipper hypertension.

METHODS

This study included 90 hypertensive patients were divided into two groups based on 24 hours ambulatory blood pressure monitoring (ABPM): 38 patients with a dipper pattern and 52 patients with non-dipper pattern. Noninvasive evaluation of the endothelial functions was performed using flow-mediated dilation (FMD) method.

RESULTS

Serum pentraxin-3 levels were higher in patients with non-dipper HT compared to dipper hypertension (P = 0.028). In addition, we found negative correlation between serum PTX3 and FMD basal/FMD hyperemia ratio (r = -0.297, P = 0.05 for FMD basal/FMD hyperemia ratio, respectively).

CONCLUSIONS

Serum PTX3 levels are closely related with the measures of indirect noninvasive evaluation methods (FMD) in both DH and NDH patients.

Pre-existing arterial pathologic changes affecting arteriovenous fistula patency and cardiovascular mortality in hemodialysis patients

The radiocephalic arteriovenous fistula (AVF) provides optimal vascular access for hemodialysis; it has a higher long-term patency rate and fewer complications than other vascular access methods. However, the AVF has a high primary failure rate. The presence of small-diameter vessels at anastomosis sites is an important risk factor for AVF failure. However, in a recent study, despite selecting an adequate artery and vein for creating an AVF by routine preoperative vascular mapping, AVF maturation and primary failure occurred. Thus, pre-existing arteriosclerosis at AVF anastomosis sites likely contributes to AVF failure. In this review, we discuss the relationship between pathologic changes and AVF patency in hemodialysis patients. Because arteriosclerosis of the major arteries such as the coronary and carotid arteries is associated with cardiovascular mortality, we also review the impact of arteriosclerosis of upper arm arteries at AVF anastomosis sites on cardiovascular mortality in hemodialysis patients.

Multifaceted interaction of bone, muscle, lifestyle interventions and metabolic and cardiovascular disease: role of osteocalcin

Undercarboxylated osteocalcin (ucOC) may play a role in glucose homeostasis and cardiometabolic health. This review examines the epidemiological and interventional evidence associating osteocalcin (OC) and ucOC with metabolic risk and cardiovascular disease. The complexity in assessing such correlations, due to the observational nature of human studies, is discussed. Several studies have reported that higher levels of ucOC and OC are correlated with lower fat mass and HbA1c. In addition, improved measures of glycaemic control via pharmacological and non-pharmacological (e.g. exercise or diet) interventions are often associated with increased circulating levels of OC and/or ucOC. There is also a relationship between lower circulating OC and ucOC and increased measures of vascular calcification and cardiovascular disease. However, not all studies have reported such relationship, some with contradictory findings. Equivocal findings may arise because of the observational nature of the studies and the inability to directly assess the relationship between OC and ucOC on glycaemic control and cardiovascular health in humans. Studying OC and ucOC in humans is further complicated due to numerous confounding factors such as sex differences, menopausal status, vitamin K status, physical activity level, body mass index, insulin sensitivity (normal/insulin resistance/T2DM), tissue-specific effects and renal function among others. Current observational and indirect interventional evidence appears to support a relationship between ucOC with metabolic and cardiovascular disease. There is also emerging evidence to suggest a direct role of ucOC in human metabolism. Further mechanistic studies are required to (a) clarify causality, (b) explore mechanisms involved and

The relation between hemoglobin variability and carotid intima-media thickness in chronic hemodialysis patients

PURPOSE

Hemoglobin variability is a common problem among hemodialysis patients. We have previously demonstrated an association between Hb variability and left ventricular mass index. In this study, we investigated a possible relation between Hb variability and carotid intima-media thickness (CIMT).

METHODS

Twelve-month hemoglobin (Hb) values of 135 patients on maintenance hemodialysis were examined retrospectively. The range of 11-12 gr/dl was accepted as normal according to the KDOQI guidelines. Hemoglobin levels were classified as: Hb < 11 gr/dl:Low, Hb = 11-12 gr/dl:Normal and Hb > 12 gr/dl:High. According to 12-month Hb trajectory, the patients were divided into three groups: low-normal (LN), normal-high (NH) and low-high (LH). The CIMT measurements were taken on common carotid arteries bilaterally, and the average of these measurements were taken. The groups were compared in terms of CIMT measurements, demographic and laboratory features.

RESULTS

The LN, NH and LH groups were similar in terms of age, gender, incidence of diabetes mellitus, hypertension and cardiovascular diseases. Duration of hemodialysis, hemodialysis adequacy, serum lipids and CaxP products were also similar among the groups. The mean CIMT value was 0.601 ± 0.107, 0.744 ± 0.139 and 0.604 ± 0.134 mm in the LN, LH and NH groups, respectively (p < 0.001). CIMT was significantly higher in LH than in the other two groups.

CONCLUSIONS

In our study, when the three groups with similar risk factors for atherosclerosis were examined, we found that the LH group with the highest hemoglobin variability has the highest CIMT. This study is the first study to demonstrate that Hb variability is associated with an increase in CIMT in HD patients.

Does the OPG/RANKL system contribute to the bone-vascular axis in chronic kidney disease? A systematic review

Vascular calcification (VC) is highly prevalent in patients with chronic kidney disease (CKD) and is strongly associated with cardiovascular mortality and morbidity. Accumulating evidence over the past decade has challenged the hypothesis of close interaction between bone and VC what raises the possibility of a common underlying pathophysiological mechanism. Lately, bone regulatory proteins such as: osteoprotegerin (OPG) and Receptor Activator for Nuclear Factor κB Ligand (RANKL) has attracted attention of researchers as a possible key mediators of bone-vascular calcification imbalance. The literature search was carried out using the MEDLINE/PubMed database and a combination of keywords and MeSH terms, and only papers published since January 2005 to July 2016 were selected. The search resulted in 562 potential articles. After selection according to the eligibility criteria, 107 studies fulfilled were included (102 full texts and 5 was case reports). OPG and RANKL plays essential role in the regulation of bone metabolism and may be regarded as a possible link between VC, bone and mineral metabolism in CKD patients. Further studies are required to determine the diagnostic significance of these proteins in evaluation of progression and severity of VC process in CKD patients. Finally, the efficacy and safety, especially in regard to VC, of anti-RANKL therapy in CKD patients requires well-designed prospective, randomized trials.

Calcification of Human Saphenous Vein Associated with Endothelial Dysfunction: A Pilot Histopathophysiological and Demographical Study

While the pathophysiology and clinical significance of arterial calcifications have been studied extensively, minimal focus has been placed on venous calcification deposition. In this study, we evaluated the association between calcium deposition in human saphenous vein (HSV), endothelial function, and patient demographic risk factors. Fifty-four HSV segments were collected at the time of coronary artery bypass graft (CABG) surgery. The presence or absence of calcium deposits was visualized using the Von Kossa staining method. Endothelial function was determined by measuring muscle tissue contraction with phenylephrine and relaxation with carbachol in a muscle bath. Additional segments of vein underwent histologic evaluation for preexisting intimal thickness and extracellular matrix (ECM) deposition. Patient demographics data were obtained through our institution’s electronic medical record, with patient consent. Calcium was present in 16 of 54 samples (29.6%). Veins with calcium deposits had significantly greater intimal-to-medial thickness ratios (p = 0.0058) and increased extracellular collagen deposition (p = 0.0077). Endothelial relaxation was significantly compromised in calcified veins vs. those without calcium (p = 0.0011). Significant patient risk factors included age (p = 0.001) and preoperative serum creatinine (p = 0.017). Calcified veins can be characterized as having endothelial dysfunction with increased basal intimal thickness and increased ECM deposition. Patient risk factors for calcium deposits in veins were similar to those for arteries, namely, advanced age and kidney disease. Further studies are needed to determine the effect of preexisting vein calcification on short- and long-term graft patency.

The molecular mechanisms of hemodialysis vascular access failure

The arteriovenous fistula has been used for more than 50 years to provide vascular access for patients undergoing hemodialysis. More than 1.5 million patients worldwide have end stage renal disease and this population will continue to grow. The arteriovenous fistula is the preferred vascular access for patients, but its patency rate at 1 year is only 60%. The majority of arteriovenous fistulas fail because of intimal hyperplasia. In recent years, there have been many studies investigating the molecular mechanisms responsible for intimal hyperplasia and subsequent thrombosis. These studies have identified common pathways including inflammation, uremia, hypoxia, sheer stress, and increased thrombogenicity. These cellular mechanisms lead to increased proliferation, migration, and eventually stenosis. These pathways work synergistically through shared molecular messengers. In this review, we will examine the literature concerning the molecular basis of hemodialysis vascular access malfunction.

Osteocalcin, Vascular Calcification, and Atherosclerosis: A Systematic Review and Meta-analysis

BACKGROUND

Osteocalcin (OC) is an intriguing hormone, concomitantly being the most abundant non-collagenous peptide found in the mineralized matrix of bone, and expanding the endocrine function of the skeleton with far-reaching extra-osseous effects. A new line of enquiry between OC and vascular calcification has emerged in response to observations that the mechanism of vascular calcification resembles that of bone mineralisation. To date, studies have reported mixed results. This systematic review and meta-analysis aimed to identify any association between OC and vascular calcification and atherosclerosis.

METHODS AND RESULTS

Databases were searched for original, peer reviewed human studies. A total of 1,453 articles were retrieved, of which 46 met the eligibility criteria. Overall 26 positive, 17 negative, and 29 neutral relationships were reported for assessments between OC (either concentration in blood, presence of OC-positive cells, or histological staining for OC) and extent of calcification or atherosclerosis. Studies that measured OC-positive cells or histological staining for OC reported positive relationships (11 studies). A higher percentage of Asian studies found a negative relationship (36%) in contrast to European studies (6%). Studies examining carboxylated and undercarboxylated forms of OC in the blood failed to report consistent results. The meta-analysis found no significant difference between OC concentration in the blood between patients with "atherosclerosis" and control (p = 0.13, n = 1,197).

CONCLUSION

No definitive association was determined between OC and vascular calcification or atherosclerosis; however, the presence of OC-positive cells and histological staining had a consistent positive correlation with calcification or atherosclerosis. The review highlighted several themes, which may influence OC within differing populations leading to inconclusive results. Large, longitudinal studies are required to further current understanding of the clinical relevance of OC in vascular calcification and atherosclerosis.

Aortic Arch Calcification Predicts Patency Loss of Arteriovenous Fistula in End-Stage Renal Disease Patients

Aortic arch calcification (AAC) is recognized as an important cardiovascular risk factor in patients with end-stage renal disease (ESRD). The aim of the study was to evaluate the impact of AAC grade on patency rates of arteriovenous fistula (AVF) in this specific population. The data of 286 ESRD patients who had an initial AVF placed were reviewed. The extent of AAC identified on chest radiography was divided into four grades (0–3). The association between AAC grade, other clinical factors, and primary patency of AVF was then analyzed by Cox proportional hazard analysis. The multivariate analysis demonstrated that the presence of AAC grade 2 (hazard ratio (95% confidence interval): 1.80 (1.15–2.84); p = 0.011) and grade 3 (3.03 (1.88–4.91); p < 0.001), and higher level of intact-parathyroid hormone (p = 0.047) were associated with primary patency loss of AVF. In subgroup analysis, which included AVF created by a surgeon assisted with preoperative vascular mapping, only AAC grade 3 (2.41 (1.45–4.00); p = 0.001), and higher intact-parathyroid hormone (p = 0.025) level were correlated with AVF patency loss. In conclusion, higher AAC grade and intact-parathyroid hormone level predicted primary patency loss of AVF in an ESRD population.

The Biology of Hemodialysis Vascular Access Failure

Arteriovenous fistulas (AVFs) are essential for patients and clinicians faced with end-stage renal disease (ESRD). While this method of vascular access for hemodialysis is preferred to others due to its reduced rate of infection and complications, they are plagued by intimal hyperplasia. The pathogenesis of intimal hyperplasia and subsequent thrombosis is brought on by uremia, hypoxia, and shear stress. These forces upregulate inflammatory and proliferative cytokines acting on leukocytes, fibroblasts, smooth muscle cells, and platelets. This activation begins initially with the progression of uremia, which induces platelet dysfunction and primes the body for an inflammatory response. The vasculature subsequently undergoes changes in oxygenation and shear stress during AVF creation. This propagates a strong inflammatory response in the vessel leading to cellular proliferation. This combined response is then further subjected to the stressors of cannulation and dialysis, eventually leading to stenosis and thrombosis. This review aims to help interventional radiologists understand the biological changes and pathogenesis of access failure.