Diagnosis of Arterial Media Calcification in Chronic Kidney Disease

Serum midkine level and its association with subclinical coronary artery calcification and carotid atherosclerosis in chronic kidney disease

BACKGROUND

There are no studies investigating the role of midkine (MK) in vascular calcification (VC) or vascular disease associated with chronic kidney disease (CKD). This study assessed serum MK level and investigated its relationship with carotid atherosclerosis and coronary artery calcification (CAC) in non-dialysis CKD.

METHODS

The study comprised 80 controls and 185 adult patients with CKD at stages 3-5 who were free of cardiovascular diseases. Acute renal failure, chronic hemodialysis, severe liver disease, inflammatory states, anticoagulation therapy and cancer were excluded. The patients were classified based on presence of CAC score into severe and mild to moderate CAC groups. They were also divided into atherosclerotic and non-atherosclerotic groups based on carotid atherosclerosis. CBC, kidney function tests, lipid profile, intact parathyroid hormone (iPTH), and phosphorus were assessed. Serum levels of MK, tumor necrosis factor- α (TNF- α), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP) were quantitatively tested using ELISA. Cardiac CT scan was done to calculate CAC score. Carotid ultrasonography was used to evaluate carotid intima media thickness (CIMT) and identify plaques.

RESULTS

All CKD categories, including CKD-3, CKD-4, and CKD-5, showed higher rates of carotid plaques (p = 0.007, p < 0.001, and p < 0.001, respectively), higher levels of MK (p < 0.001 for each), and higher CAC scores (p < 0.001 for each) as CKD worsened. Compared to mild to moderate CAC patients, severe CAC patients showed increased CIMT (p < 0.001) and raised serum levels of MK (p < 0.001), TNF-α (p = 0.001), IL-6 (p = 0.002), hs-CRP (p = 0.003), iPTH (p = 0.02), phosphorus (p < 0.001), total cholesterol (TC), and low density lipoprotein-cholesterol (LDL-C). Multivariate linear regression revealed that CAC was reliably predicted by MK (p = 0.008) and serum creatinine (p = 0.001). Carotid atherosclerotic patients had higher serum levels of MK, TNF-α, IL-6, hs-CRP, iPTH, phosphorus, TC, total triglycerides and LDL-C (p < 0.001 for each). Multivariate logistic regression showed that serum MK (p = 0.001), serum creatinine (p = 0.005), age (p < 0.001), iPTH (p = 0.007), and IL-6 (p = 0.024) were significant predictors of carotid atherosclerosis.

CONCLUSIONS

As CKD worsened, MK levels, carotid atherosclerosis and CAC increased. Serum MK was a reliable biomarker for asymptomatic carotid atherosclerosis and CAC in non-dialysis CKD, allowing prompt early diagnosis to avert cardiovascular morbidity and death in the future.

TRIAL REGISTRATION

The trial number was 1138 and its registration was approved by the hospital's Research Ethics Committee in 4/2024.

The Complex Mechanisms and the Potential Effects of Statins on Vascular Calcification: A Narrative Review

Vascular calcification (VC) is a complex process of calcium deposition on the arterial wall and atherosclerotic plaques and involves interaction between vascular smooth muscle cells, inflammatory and VC mediators. The latter are independent predictors of cardiovascular morbidity and mortality and potential targets of pharmaceutical therapy. This paper is a narrative review of the complex mechanisms of VC development and in this context the potential anti-atherosclerotic effects of statins. At the initial stages of atherosclerosis VC correlates with atherosclerosis burden and in the long-term with cardiovascular morbidity and mortality. A plethora of animal and clinical studies have proposed statins as the cornerstone of primary and secondary prevention of atherosclerotic cardiovascular disease. Based on coronary computed tomography data, high doses of statins may have negligible or even positive effects on the progression of coronary artery calcification. Growing data support an increase in atherosclerotic plaque calcification in peripheral arteries (e.g., carotids), after long-term, statin-therapy. Despite the paradox of increasing VC, those effects of statins have been associated with higher plaque stability, reducing the risk of consequent adverse events. Statins seem to promote a "favorable" atherosclerotic calcification, suppressing atherosclerotic lesion expansion and their vulnerability. More studies are required to clarify the underlying mechanisms.

Epidermal growth factor receptor inhibition prevents vascular calcifying extracellular vesicle biogenesis

Chronic kidney disease (CKD) increases the risk of cardiovascular disease, including vascular calcification, leading to higher mortality. The release of calcifying extracellular vesicles (EVs) by vascular smooth muscle cells (VSMCs) promotes ectopic mineralization of vessel walls. Caveolin-1 (CAV1), a structural protein in the plasma membrane, plays a major role in calcifying EV biogenesis in VSMCs. Epidermal growth factor receptor (EGFR) colocalizes with and influences the intracellular trafficking of CAV1. Using a diet-induced mouse model of CKD followed by a high-phosphate diet to promote vascular calcification, we assessed the potential of EGFR inhibition to prevent vascular calcification. Furthermore, we computationally analyzed 7,651 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) and Framingham cohorts to assess potential correlations between coronary artery calcium and single-nucleotide polymorphisms (SNPs) associated with elevated serum levels of EGFR. Mice with CKD developed widespread vascular calcification, associated with increased serum levels of EGFR. In both the CKD mice and human VSMC culture, EGFR inhibition significantly reduced vascular calcification by mitigating the release of CAV1-positive calcifying EVs. EGFR inhibition also increased bone mineral density in CKD mice. Individuals in the MESA and Framingham cohorts with SNPs associated with increased serum EGFR exhibit elevated coronary artery calcium. Given that EGFR inhibitors exhibit clinical safety and efficacy in other pathologies, the current data suggest that EGFR may represent an ideal target to prevent pathological vascular calcification in CKD.NEW & NOTEWORTHY Here, we investigate the potential of epidermal growth factor receptor (EGFR) inhibition to prevent vascular calcification, a leading indicator of and contributor to cardiovascular morbidity and mortality. EGFR interacts and affects the trafficking of the plasma membrane scaffolding protein caveolin-1. Previous studies reported a key role for caveolin-1 in the development of specialized extracellular vesicles that mediate vascular calcification; however, no role of EGFR has been reported. We demonstrated that EGFR inhibition modulates caveolin-1 trafficking and hinders calcifying extracellular vesicle formation, which prevents vascular calcification. Given that EGFR inhibitors are clinically approved for other indications, this may represent a novel therapeutic strategy for vascular calcification.

Serum and Urinary Soluble α-Klotho as Markers of Kidney and Vascular Impairment

This study was designed to investigate the controversy on the potential role of sKlotho as an early biomarker in Chronic Kidney Disease–Mineral Bone Disorder (CKD-MBD), to assess whether sKlotho is a reliable marker of kidney α-Klotho, to deepen the effects of sKlotho on vascular smooth muscle cells (VSMCs) osteogenic differentiation and to evaluate the role of autophagy in this process. Experimental studies were conducted in CKD mice fed a normal phosphorus (CKD+NP) or high phosphorus (CKD+HP) diet for 14 weeks. The patients’ study was performed in CKD stages 2–5 and in vitro studies which used VSMCs exposed to non-calcifying medium or calcifying medium with or without sKlotho. The CKD experimental model showed that the CKD+HP group reached the highest serum PTH, P and FGF23 levels, but the lowest serum and urinary sKlotho levels. In addition, a positive correlation between serum sKlotho and kidney α-Klotho was found. CKD mice showed aortic osteogenic differentiation, together with increased autophagy. The human CKD study showed that the decline in serum sKlotho is previous to the rise in FGF23. In addition, both serum sKlotho and FGF23 levels correlated with kidney function. Finally, in VSMCs, the addition of sKlotho prevented osteogenic differentiation and induced autophagy. It can be concluded that serum sKlotho was the earliest CKD-MBD biomarker, a reliable indicator of kidney α-Klotho and that might protect against osteogenic differentiation by increasing autophagy. Nevertheless, further studies are needed to investigate the mechanisms of this possible protective effect.

The pathophysiology and management of vascular calcification in chronic kidney disease patients

INTRODUCTION

Vascular calcification (VC) which is the pathological mineral deposition in the vascular system, predominantly at the intimal and medial layer of the vessel wall, is an important comorbidity in patients with chronic kidney disease (CKD) leading to significant morbidity and mortality while necessitating appropriate treatment. Our review aims to provide an in-depth analysis of the current understanding of VC.

AREAS COVERED

In this review, we first discuss the pathophysiology of VC in CKD patients, then we explain the methods to predict and assess VC. Afterwards, we provide the currently available as well as the potential therapeutic approaches of VC. We finally discuss our understanding regarding the current situation surrounding VC in our expert opinion section.

EXPERT OPINION

Predicting, assessing and treating VC is crucial and the future advances in the field of research surrounding VC will potentially occur in one or more of these three areas of clinical management. There is a current lack of evidence and consensus regarding specific therapeutic options for alleviating VC and this situation may not necessitate VC to be determined, detected, and documented before the available options are implemented. Regardless, the prediction and assessment of VC is still important and requires further improvement together with the developments in therapeutic alternatives. The future has the potential to bring better research which would guide and improve the management of this patient group. A more specialized approach consisting of targeted therapies and more tailored management plans for patients with CKD and VC is on the horizon.

Analysis of Extracellular Vesicle-Mediated Vascular Calcification Using In Vitro and In Vivo Models

Cardiovascular disease is the leading cause of death in the world, and vascular calcification is the most significant predictor of cardiovascular events; however, there are currently no treatment or therapeutic options for vascular calcification. Calcification begins within specialized extracellular vesicles (EVs), which serve as nucleating foci by aggregating calcium and phosphate ions. This protocol describes methods for obtaining and assessing calcification in murine aortas and analyzing the associated extracted EVs. First, gross dissection of the mouse is performed to collect any relevant organs, such as the kidneys, liver, and lungs. Then, the murine aorta is isolated and excised from the aortic root to the femoral artery. Two to three aortas are then pooled and incubated in a digestive solution before undergoing ultracentrifugation to isolate the EVs of interest. Next, the mineralization potential of the EVs is determined through incubation in a high-phosphate solution and measuring the light absorbance at a wavelength of 340 nm. Finally, collagen hydrogels are used to observe the calcified mineral formation and maturation produced by the EVs in vitro.

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.

Vascular Calcification in Chronic Kidney Disease: Distinct Features of Pathogenesis and Clinical Implication

Chronic kidney disease (CKD) is associated with a higher prevalence of vascular calcification (VC) and cardiovascular disease. VC in CKD patients showed different pathophysiological features from those of the general population. The pathogenesis of VC in CKD is a highly organized process, and prior studies have suggested that patients with CKD have their own specific contributors to the phenotypic change of vascular smooth muscle cells (VSMCs), including uremic toxins, CKD-mineral and bone disease (CKD-MBD), inflammation, and oxidative stress. For the diagnosis and monitoring of VC in CKD, several imaging modalities, including plain radiography, ultrasound, and computed tomography have been utilized. VC in CKD patients has distinct clinical features and implications. CKD patients revealed a more intense and more prevalent calcification on the intimal and medial layers, whereas intimal calcification is predominantly observed in the general population. While a higher VC score is clearly associated with a higher risk of all-cause mortality and cardiovascular events, a greater VC score in CKD patients does not fully reflect the burden of atherosclerosis, because they have more calcification at equal volumes of atheromatous plaques. The primary goal of VC treatment in CKD is the prevention of VC progression, and the main management is to control the biochemical components of CKD-MBD. Cinacalcet and non-calcium-containing phosphate binders are the mainstay of VC prevention in CKD-MBD management. VC in patients with CKD is an ongoing area of research and is expected to advance soon.

Evaluation of the relationship between blood cell parameters and vascular calcification in dialysis-dependent end-stage renal disease patients

Coronary artery calcification is an acceptable tool for cardiovascular risk assessment in end-stage renal disease (ESRD) population. We aimed to identify the association and predictive value of components of blood cell parameters with coronary and thoracic aorta vascular calcification (VC) in ESRD population on dialysis. All ESRD patients receiving hemodialysis or peritoneal dialysis aged between 18 and 60 years were included in the study. Exclusion criteria comprised patients with active infection or inflammatory disease, autoimmune disease, congestive heart failure, angina pectoris and/or documented coronary artery disease, thyroid disease, and hepatic dysfunction. Agatston scoring was used for the evaluation of coronary aorta calcification (CAC) score (CACS) and thoracic aorta calcification (TAC) score (TACS). Compared to participants with no VC, those who had VC were statistically significantly older (P <0.001) and had higher neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) (P = 0.02 and <0.001, respectively). On multivariate logistic regression analysis, increasing age (P = 0.00) and higher PLR (P = 0.04) were associated with an increased likelihood of exhibiting VC (CAC or TAC). There was a positive correlation between CACS and age (rs = 0.495, P = 0.00). A statistically significant positive correlation existed between TACS and age (rs = 0.516, P = 0.00). Similarly, a positive correlation was found between NLR, PLR, and TACS (rs = 0.334, P = 0.001, and rs = 0.438, P = 0.00, respectively). On multivariate linear regression analysis, increased age and red cell distribution width were found to be significant predictors of log(n) TACS. PLR of 135 gave a sensitivity of 80% and a specificity of 50% for predicting VC. Being a cost-effective and easily available investigation, the utilization of the correlation of NLR and PLR with CAC and TAC appears promising, particularly in the age group of 30-60 years.

Routine mammography: an opportunity for the diagnosis of chronic degenerative diseases? A cross-sectional study

Objective

The aim of this study was to evaluate breast arterial calcification (BAC) detected on routine mammography, analyzing its association with chronic degenerative disease.

Materials and Methods

This was a cross-sectional study involving women treated at a specialized outpatient clinic for high-risk hypertension, diabetes, or chronic kidney disease, as well as volunteers who participated in a study to validate a method of screening for occult renal disease. A total of 312 patients between 40 and 69 years of age, with no history of breast cancer, all of whom had undergone routine mammography in the last two years, were included. The mammograms were analyzed by researchers who were unaware of the risk factors for BAC in each case.

Results

The mean age was 55.9 ± 7.4 years, and 64.3% of the patients were white. The mean glomerular filtration rate was 41.87 ± 6.23 mL/min/1.73 m². Seventy-one patients (22.8%) had BAC. We found that BAC was associated with advanced age, hypertension, diabetes, chronic kidney disease, and low glomerular filtration rate. In the multivariate analysis, advanced age and diabetes continued to be associated with BAC. The odds ratio for BAC was higher for all chronic diseases.

Conclusion

The association of BAC with advanced age, hypertension, diabetes, chronic kidney disease, and low glomerular filtration rate should call the attention of radiologists. Therefore, the presence of BAC should be reported, and patients with BAC should be screened for those diseases.

Non-traumatic calcifications/ossifications of the bone surface and soft tissues of the wrist, hand and fingers: a diagnostic approach

In the absence of obvious trauma, the calcifications/ossifications of the bone surface and soft tissues of the wrist, hand and fingers can be challenging and may not be noticed or lead to unnecessary examinations and monitoring. Although these are usually benign conditions and despite a favorable spontaneous outcome, surgical resection may be required and recurrence may occur. In practice, only paraneoplastic syndromes such as secondary hypertrophic osteoarthropathy (Pierre Marie-Bamberger syndrome) may reveal a malignant tumor, most often pulmonary. We suggest a diagnostic approach based on the initial clinical presentation (acute pain, chronic pain, growth±pain) and the radiological features.