Calciprotein Particles Link Disturbed Mineral Homeostasis with Cardiovascular Disease by Causing Endothelial Dysfunction and Vascular Inflammation

An association between high serum calcium/phosphate and cardiovascular events or death is well-established. However, a mechanistic explanation of this correlation is lacking. Here, we examined the role of calciprotein particles (CPPs), nanoscale bodies forming in the human blood upon its supersaturation with calcium and phosphate, in cardiovascular disease. The serum of patients with coronary artery disease or cerebrovascular disease displayed an increased propensity to form CPPs in combination with elevated ionised calcium as well as reduced albumin levels, altogether indicative of reduced Ca2+-binding capacity. Intravenous administration of CPPs to normolipidemic and normotensive Wistar rats provoked intimal hyperplasia and adventitial/perivascular inflammation in both balloon-injured and intact aortas in the absence of other cardiovascular risk factors. Upon the addition to primary human arterial endothelial cells, CPPs induced lysosome-dependent cell death, promoted the release of pro-inflammatory cytokines, stimulated leukocyte adhesion, and triggered endothelial-to-mesenchymal transition. We concluded that CPPs, which are formed in the blood as a result of altered mineral homeostasis, cause endothelial dysfunction and vascular inflammation, thereby contributing to the development of cardiovascular disease.

PSVIII-22 Maternal vitamin and mineral supplementation affect fetal hepatic expression of genes underlying mineral homeostasis and lipid metabolism in early pregnancy

Vitamins and minerals play critical roles in functions such as hormone production, DNA synthesis, regulation of gene expression, and lipid metabolism. However, the impact of vitamin and mineral supplementation on fetal programming and the interplay with gene expression of fetal organs remains unclear. We used a differential gene expression analysis to determine effects of maternal vitamin and mineral supplementation (from pre-breeding to d 83 post-breeding) on fetal hepatic gene expression and the pathways underlying liver function and metabolism at 83 d of gestation. Crossbred Angus beef heifers were supplemented (VTM, n = 7) or not (CON, n = 8) with 113 g•heifer-1•d-1 of mineral premix (Purina® Wind & Rain Storm All-Season 7.5 Complete) from a minimum d 71 before breeding through d 83 of gestation. After breeding, heifers were fed to gain 0.79 kg/d. All heifers were surgically ovariohysterectomized on d 83 and fetal liver collected. Total RNA was isolated from the fetal liver (n = 15) and gene expression measured with RNA-Seq. After library quality control and read mapping, differential expression was performed using edgeR. We identified 53 genes upregulated and 37 downregulated in the VTM group (adj.Pval < 0.1). Genes involved with mineral homeostasis, such as MT1A, MT1E, and MT2A, were among those differentially expressed underlying the mineral absorption pathway. ABCA1 and ABCA6, which are involved in cholesterol and metal ion transport across the plasma membrane, and PPARG and SDR16C5, that act on lipoprotein transport and metabolism, were upregulated in the VTM group. Also upregulated in the VTM group, the CUBN gene plays a role in vitamin and iron metabolism. In summary, maternal vitamin and mineral supplementation from pre-breeding to d 83 of gestation leads to upregulation of fetal hepatic genes acting on mineral homeostasis, lipid transport, and metabolism.

Regularities of plaque stabilization in various scenarios of neointimal calcification and vascularization

Aim. To study the relationships between phenotypes of extracranial arteries' plaques (stable/unstable), their calcification and its causes, in particular, vascularization.Material and methods. The study included 88 patients: patients (n=44) with ischemic stroke and those (n=44) with chronic brain ischemia. In all subjects, the parameters of systemic mineral homeostasis were assessed (total and ionized calcium, phosphate, total protein, albumin, and calcification propensity). Atherosclerotic plaques have been obtained during carotid endarterectomy, fixed in formalin, postfixed in 1% osmium tetroxide, stained in 2% osmium tetroxide, dehydrated in ascending ethanol series and acetone, stained with 2% alcoholic uranyl acetate and embedded into epoxy resin with its further polymerization. Epoxy resin blocks were grinded, polished, counterstained with Reynolds' lead citrate and sputter coated with carbon. Sample visualization was performed employing backscattered scanning electron microscopy. Number and area of calcium deposits and neointimal vessels were quantified using ImageJ. Statistical analysis was carried out using Mann-Whitney U-test and Spearman's rank correlation coefficient.Results. It was found that area of neointimal calcification, but not number of calcium deposits, was associated with the stable plaque phenotype. The stabilizing effect of calcification was manifested in retarding stenosis associated with plaque rupture and stroke. Calcification extent directly correlated with total and local plaque vascularization, which have been associated with unstable and stable plaque phenotype, respectively. In addition, plaque calcification negatively correlated with total protein and albumin, thereby reflecting the impaired systemic mineral homeostasis.Conclusion. Atherosclerotic plaque calcification and active local vascularization reduce stenosis extent and stabilize plaque. In contrast, total plaque calcification contributes to the atherosclerosis progression and promotes major acute cardiovascular events.

Analysis of the Prevalence and Severity of Dysregulated Bone Mineral Homeostasis in Nondialyzed Chronic Kidney Disease Patients

Background Progressive loss of kidney function in chronic kidney disease (CKD) leads to altered mineral homeostasis, reflected by the imbalance in calcium and phosphorus, and has been associated with progression of renal failure. Aims The aim of this study was to investigate CKD-mineral bone disorder (CKD-MBD)-associated candidate variables and its relationship with parathyroid hormone (PTH), as well as to quantify the prevalence of CKD-associated mineral disturbances in nondialyzed CKD patients. Study Design, Materials, and Methods This cross-sectional analytical study included 124 CKD patients and 157 control participants. Blood samples were analyzed for serum total calcium, phosphorus, PTH, electrolytes, and other hematological/hemodynamic parameters by standard methods. Suitable descriptive statistics was used for different variables. Results The 124 patients had a mean age of 50.2 ± 7.8 years with male to female ratio of 1.58; majority of patients had stage 3 CKD (40.32%), and the most common comorbid conditions were diabetes mellitus ( n = 78 [62.9%]) and hypertension ( n = 63 [50.8%]). A high prevalence of mineral metabolite abnormalities was observed in a patient cohort; overall prevalence of hyperparathyroidism was found in 57.25% patients, hypocalcemia in 61.29%, and hyperphosphatemia in 82.25% patients. Prevalence of abnormal homeostasis (with regard to total calcium, phosphate, and PTH) increased progressively with the severity of disease (analysis of variance; p < 0.05). Significant differences in the mean values of total calcium, phosphorus, alkaline phosphatase, and PTH were seen compared with healthy participants ( p < 0.0001). Furthermore, there was a significant positive correlation between serum PTH with serum phosphorous ( R 2: 0.33; p < 0.0001), serum creatinine ( R 2: 0.084; p < 0.0259), serum potassium ( R 2: 0.068; p < 0.0467), and a significant negative correlation with serum total calcium ( R 2: 0.37; p < 0.0001). Conclusions CKD patients are at risk of or may already have developed secondary hyperparathyroidism apparent from PTH-linked derangements in mineral metabolism in predialysis CKD patients. These abnormalities start in early stages of CKD and worsen with disease progression. This accentuates the significance of early recognition of mineral bone disorder, understanding its pathophysiological consequences and scheduling necessary interventions/management strategies to protect the CKD patients from a plethora of complications.

Pathophysiological and clinical significance of mineral homeostasis disorders in the development of cardiovascular disease

A growing incidence, prevalence, morbidity and mortality from cardiovascular disease dictate an urgent need in identification of its risk factors and their pathogenetic links with coronary artery disease and stroke. Aging of the population is inevitably associated with an increasing prevalence of comorbid conditions. Among them are disorders of mineral homeostasis which, often being neglected, are clearly associated with major adverse cardiovascular events and cardiovascular death. Maintenance of mineral homeostasis in the human body is largely dependent on the formation of calciprotein particles (CPPs) which arise in the blood upon the binding of a mineral chaperone fetuin-A to nascent calcium phosphate crystals, thereby aggregating excessive calcium (Ca2+) and phosphate (PO4 3-), removing them from the bloodstream and preventing extraskeletal calcification. During the circulation, CPPs are internalised by arterial endothelial cells and provoke endothelial dysfunction through endothelial activation, endothelialto-mesenchymal transition and impairment of endothelial mechanotransduction. Animal studies demonstrated that regular intravenous injections of CPPs lead to intimal hyperplasia and adventitial/perivascular inflammation in the absence of any other cardiovascular risk factors, indicating pathophysiological importance of CPPs for cardiovascular disease. Further, a number of clinical studies suggested an association of an augmented serum calcification propensity or elevated CPP count with arterial hypertension, myocardial infarction, chronic brain ischemia, ischemic stroke and cardiovascular death in patients with chronic kidney disease (including those with end-stage renal disease as well as kidney transplant recipients) and individuals with a preserved renal function. Here, we critically discuss the pathophysiological consequences of CPP formation, mechanisms of their pathogenic effects, and potential therapeutic interventions.

MINERAL HOMEOSTASIS OF THE ORAL FLUID IN CHILDREN AND ADOLESCENTS WHO HAVE UNDERGONE TREATMENT OF MALIGNANT NEOPLASMS

Annotation. The authors' study highlights the urgent problem of the development of toxic damage to the dentition under the influence of anticancer therapy in children and adolescents. The aim of the study was to study the violation of the homeostasis of the oral fluid and the severity of the carious process. Materials and methods. As part of a pilot study at the Russian Field Treatment and Rehabilitation Center, 63 children were studied the severity of mineral homeostasis disorders and damage to the dentoalveolar system. Results. In 67% of patients in the main group, there was an increased tendency to form carious cavities. 54.5% of them have complicated caries. One third of patients had more than five carious teeth. In the control group, carious lesions of the teeth in only three patients (20%), with the involvement of 1-3 teeth in the pathological process. Violation of enamel formation was diagnosed in 36% of children of the main group. There is a tendency for the accumulation of the studied microelements in the oral fluid, while in the blood serum there is a normal or insignificant decrease in their content. According to the literature, this may indicate destruction in the oral cavity. Deviations in the homeostasis of chemical elements in children who completed the treatment of malignant neoplasms and children in the control group were revealed. An increased content of osteotrophic microelements was found to correlate with the destructive processes of the teeth. Conclusion. It seems appropriate to study the severity of morphological changes in hard tissues of teeth and the electrolyte composition of mixed saliva in children and adolescents who have been cured of malignant neoplasms. The results of studies of gastric cancer, as an indicator of metabolic disorders, will make it possible not only to reveal the imbalance of macro- and microelements, but also to establish the effectiveness of adaptation mechanisms aimed at normalizing the elemental composition of the oral fluid.

Transcriptional responses in jejunum of two layer chicken strains following variations in dietary calcium and phosphorus levels

Background Calcium (Ca) and phosphorus (P) are essential nutrients that are linked to a large array of biological processes. Disturbances in Ca and P homeostasis in chickens are associated with a decline in growth and egg laying performance and environmental burden due to excessive P excretion rates. Improved utilization of minerals in particular of P sources contributes to healthy growth while preserving the finite resource of mineral P and mitigating environmental pollution. In the current study, high performance Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) hens at peak laying performance were examined to approximate the consequences of variable dietary Ca and P supply. The experimental design comprised four dietary groups with standard or reduced levels of either Ca or P or both (n = 10 birds per treatment group and strain) in order to stimulate intrinsic mechanisms to maintain homeostasis. Jejunal transcriptome profiles and the systemic endocrine regulation of mineral homeostasis were assessed (n = 80). Results Endogenous mechanisms to maintain mineral homeostasis in response to variations in the supply of Ca and P were effective in both laying hen strains. However, the LSL and LB appeared to adopt different molecular pathways, as shown by circulating vitamin D levels and strain-specific transcriptome patterns. Responses in LSL indicated altered proliferation rates of intestinal cells as well as adaptive responses at the level of paracellular transport and immunocompetence. Endogenous mechanisms in LB appeared to involve a restructuring of the epithelium, which may allow adaptation of absorption capacity via improved micro-anatomical characteristics. Conclusions The results suggest that LSL and LB hens may exhibit different Ca, P, and vitamin D requirements, which have so far been neglected in the supply recommendations. There is a demand for trial data showing the mechanisms of endogenous factors of Ca and P homeostasis, such as vitamin D, at local and systemic levels in laying hens.