Circulating osteopontin as a marker of early coronary vascular calcification in type two diabetes mellitus patients with known asymptomatic coronary artery disease

The Role of Osteopontin in Atherosclerosis and Its Clinical Manifestations (Atherosclerotic Cardiovascular Diseases)-A Narrative Review

Atherosclerotic cardiovascular diseases (ASCVDs) are the most common and severe public health problem nowadays. Osteopontin (OPN) is a multifunctional glycoprotein highly expressed at atherosclerotic plaque, which has emerged as a potential biomarker of ASCVDs. OPN may act as an inflammatory mediator and/or a vascular calcification (VC) mediator, contributing to atherosclerosis progression and eventual plaque destabilization. In this article, we discuss the complex role of OPN in ASCVD pathophysiology, since many in vitro and in vivo experimental data indicate that OPN contributes to macrophage activation and differentiation, monocyte infiltration, vascular smooth muscle cell (VSMC) migration and proliferation and lipid core formation within atherosclerotic plaques. Most but not all studies reported that OPN may inhibit atherosclerotic plaque calcification, making it "vulnerable". Regarding clinical evidence, serum OPN levels may become a biomarker of coronary artery disease (CAD) presence and severity. Significantly higher OPN levels have been found in patients with acute coronary syndromes than those with stable CAD. In limited studies of patients with peripheral artery disease, circulating OPN concentrations may be predictive of future major adverse cardiovascular events. Overall, the current literature search suggests the contribution of OPN to atherosclerosis development and progression, but more robust evidence is required.

Cationic proteins from eosinophils bind bone morphogenetic protein receptors promoting vascular calcification and atherogenesis

AIMS

Blood eosinophil count and eosinophil cationic protein (ECP) concentration are risk factors of cardiovascular diseases. This study tested whether and how eosinophils and ECP contribute to vascular calcification and atherogenesis.

METHODS AND RESULTS

Immunostaining revealed eosinophil accumulation in human and mouse atherosclerotic lesions. Eosinophil deficiency in ΔdblGATA mice slowed atherogenesis with increased lesion smooth muscle cell (SMC) content and reduced calcification. This protection in ΔdblGATA mice was muted when mice received donor eosinophils from wild-type (WT), Il4-/-, and Il13-/- mice or mouse eosinophil-associated-ribonuclease-1 (mEar1), a murine homologue of ECP. Eosinophils or mEar1 but not interleukin (IL) 4 or IL13 increased the calcification of SMC from WT mice but not those from Runt-related transcription factor-2 (Runx2) knockout mice. Immunoblot analyses showed that eosinophils and mEar1 activated Smad-1/5/8 but did not affect Smad-2/3 activation or expression of bone morphogenetic protein receptors (BMPR-1A/1B/2) or transforming growth factor (TGF)-β receptors (TGFBR1/2) in SMC from WT and Runx2 knockout mice. Immunoprecipitation showed that mEar1 formed immune complexes with BMPR-1A/1B but not TGFBR1/2. Immunofluorescence double-staining, ligand binding, and Scatchard plot analysis demonstrated that mEar1 bound to BMPR-1A and BMPR-1B with similar affinity. Likewise, human ECP and eosinophil-derived neurotoxin (EDN) also bound to BMPR-1A/1B on human vascular SMC and promoted SMC osteogenic differentiation. In a cohort of 5864 men from the Danish Cardiovascular Screening trial and its subpopulation of 394 participants, blood eosinophil counts and ECP levels correlated with the calcification scores of different arterial segments from coronary arteries to iliac arteries.

CONCLUSION

Eosinophils release cationic proteins that can promote SMC calcification and atherogenesis using the BMPR-1A/1B-Smad-1/5/8-Runx2 signalling pathway.

A New Perspective on Metabolic Syndrome with Osteopontin: A Comprehensive Review

Metabolic syndrome (MetS) imposes a substantial burden on the healthcare systems and economies of countries and is a major public health concern worldwide. MetS is mainly caused by an imbalance between calorie intake and energy expenditure; however, it is recognized that additional variables, such as chronic inflammation, may have the same predictive potential as insulin resistance or MetS components in the genesis of type 2 diabetes and cardiovascular events. More importantly, the early diagnosis or treatment of MetS may significantly reduce the burden on the health systems of the disease with any prevention or biomarker and should not be underestimated. Osteopontin (OPN), also called secreted phosphoprotein 1, is a soluble protein found mostly in body fluids. Studies suggest that serum OPN levels may be an early and new biomarker to predict metabolic and cardiovascular complications significantly associated with some diseases. This review aims to provide specific insight into the new biomarker OPN in MetS. With this purpose, it is examined the link between the MetS cornerstones and OPN. In addition, the interaction between the microbiota and MetS is predicted to be bidirectional, and the microbiota may act as a bridge in this interaction process. Increased OPN levels may have unfavourable consequences for cardiovascular diseases, diabetes, and obesity, all of which are components of MetS. Further studies are required to evaluate the use of OPN levels as a clinical biomarker risk of MetS.

Biomarkers of Atrial Fibrillation Recurrence in Patients with Paroxysmal or Persistent Atrial Fibrillation Following External Direct Current Electrical Cardioversion

Atrial fibrillation (AF) is associated with atrial remodeling, cardiac dysfunction, and poor clinical outcomes. External direct current electrical cardioversion is a well-developed urgent treatment strategy for patients presenting with recent-onset AF. However, there is a lack of accurate predictive serum biomarkers to identify the risks of AF relapse after electrical cardioversion. We reviewed the currently available data and interpreted the findings of several studies revealing biomarkers for crucial elements in the pathogenesis of AF and affecting cardiac remodeling, fibrosis, inflammation, endothelial dysfunction, oxidative stress, adipose tissue dysfunction, myopathy, and mitochondrial dysfunction. Although there is ample strong evidence that elevated levels of numerous biomarkers (such as natriuretic peptides, C-reactive protein, galectin-3, soluble suppressor tumorigenicity-2, fibroblast growth factor-23, turn-over collagen biomarkers, growth differential factor-15) are associated with AF occurrence, the data obtained in clinical studies seem to be controversial in terms of their predictive ability for post-cardioversion outcomes. Novel circulating biomarkers are needed to elucidate the modality of this approach compared with conventional predictive tools. Conclusions: Biomarker-based strategies for predicting events after AF treatment require extensive investigation in the future, especially in the presence of different gender and variable comorbidity profiles. Perhaps, a multiple biomarker approach exerts more utilization for patients with different forms of AF than single biomarker use.

Prognostic role of osteoprotegerin and risk of coronary artery calcification: a systematic review and meta-analysis

Aim: Coronary artery calcification (CAC) is a predictor of atherosclerosis. However, the association of osteoprotegerin (OPG) with CAC is still controversial. Methods: Prospective cohort studies that provided odds ratios with 95% CIs were included from PubMed, Embase, Web of Science and Scopus through July 2022. Results: Out of 14 studies included in the systematic review, three studies with 7642 participants were included in the meta-analysis. The pooled odds ratio indicated a significant association between higher OPG levels and accelerated risk of CAC (1.15; 95% CI: 1.03-1.30; p < 0.001) with relatively no heterogeneity between studies (I² = 0%; p = 0.43). Conclusion: The results indicated that increased concentrations of OPG are positively associated with a 15% elevated odds of CAC after adjustment of major covariates.

The clinical significance of osteopontin on the cardiovascular outcomes in patients with stable coronary artery disease

BACKGROUND

Osteopontin (OPN) is a noncollagenous matricellular protein which is mainly present in bone matrix. A high OPN level has been associated with heart failure and acute coronary syndrome, however data on patients with chronic coronary syndrome (CCS) are lacking. The present study aimed to evaluate the association between OPN and the prognosis of Taiwanese patients with CCS.

METHODS

We enrolled participants from the Biosignature Registry, a nationwide prospective cohort study conducted at nine different medical centers throughout Taiwan. The inclusion criteria were participants who had received successful percutaneous coronary intervention at least once previously, and stable under medical therapy for at least 1 month before enrollment. They were followed for at least 72 months. Logistic regression and Cox proportional hazard model were used to investigate the association between OPN and clinical outcomes. The outcomes of this study were the first occurrence of hard cardiovascular events and composite cardiovascular outcomes including cardiovascular mortality, revascularization, hospitalization for acute myocardial infarction (AMI) or heart failure.

RESULTS

A total of 666 patients with both hs-CRP and osteopontin measurements were enrolled and followed for 72 months. OPN was correlated positively with AMI-related hospitalization, where the highest tertile (Tertile 3) of baseline OPN had the highest risk of AMI-related hospitalization, which remained significant after multivariate adjustments (HR 3.20, p = 0.017). In contrast, combining OPN and hs-CRP did not improve the prediction of CV outcomes.

CONCLUSION

OPN may be a potentially valuable biomarker in predicting CV outcomes. During 6 years of follow-up period, an OPN level >4810 pg/ml was associated with a significantly higher incidence of AMI-related hospitalization in CCS patients who received successful PCI before the enrollment.

Serum biomarkers for arterial calcification in humans: A systematic review

Aim

To clarify the role of mediators of ectopic mineralization as biomarkers for arterial calcifications.

Methods

MEDLINE and Embase were searched for relevant literature, until January 4th 2022. The investigated biomarkers were: calcium, phosphate, parathyroid hormone, vitamin D, pyrophosphate, osteoprotegerin, receptor activator of nuclear factor-kappa B ligand (RANKL), fibroblast growth factor-23 (FGF-23), Klotho, osteopontin, osteocalcin, Matrix Gla protein (MGP) and its inactive forms and vitamin K. Studies solely performed in patients with kidney insufficiency or diabetes mellitus were excluded.

Results

After screening of 8985 articles, a total of 129 articles were included in this systematic review. For all biomarkers included in this review, the results were variable and more than half of the studies for each specific biomarker had a non-significant result. Also, the overall quality of the included studies was low, partly as a result of the mostly cross-sectional study designs. The largest body of evidence is available for phosphate, osteopontin and FGF-23, as a little over half of the studies showed a significant, positive association. Firm statements for these biomarkers cannot be drawn, as the number of studies was limited and hampered by residual confounding or had non-significant results. The associations of the other mediators of ectopic mineralization with arterial calcifications were not clear.

Conclusion

Associations between biomarkers of ectopic mineralization and arterial calcification are variable in the published literature. Future longitudinal studies differentiating medial and intimal calcification could add to the knowledge of biomarkers and mechanisms of arterial calcifications.

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We researched the association between biomarkers and arterial calcifications.

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This review focused on biomarkers of bone metabolism and Matrix Gla protein.

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Associations between biomarkers and arterial calcification are variable.

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Future studies should differentiate between medial and intimal calcifications.

Osteopontin accumulates in basal deposits of human eyes with age-related macular degeneration and may serve as a biomarker of aging

A common clinical phenotype of several neurodegenerative and systemic disorders including Alzheimer's disease and atherosclerosis is the abnormal accumulation of extracellular material, which interferes with routine cellular functions. Similarly, patients with age-related macular degeneration (AMD), the leading cause of vision loss among the aged population, present with extracellular lipid- and protein-filled basal deposits in the back of the eye. While the exact mechanism of growth and formation of these deposits is poorly understood, much has been learned from investigating their composition, providing critical insights into AMD pathogenesis, prevention, and therapeutics. We identified human osteopontin (OPN), a phosphoprotein expressed in a variety of tissues in the body, as a newly discovered component of basal deposits in AMD patients, with a distinctive punctate staining pattern. OPN expression within these lesions, which are associated with AMD disease progression, were found to co-localize with abnormal calcium deposition. Additionally, OPN puncta colocalized with an AMD risk-associated complement pathway protein, but not with apolipoprotein E or vitronectin, two other well-established basal deposit components. Mechanistically, we found that retinal pigment epithelial cells, cells vulnerable in AMD, will secrete OPN into the extracellular space, under oxidative stress conditions, supporting OPN biosynthesis locally within the outer retina. Finally, we report that OPN levels in plasma of aged (non-AMD) human donors were significantly higher than levels in young (non-AMD) donors, but were not significantly different from donors with the different clinical subtypes of AMD. Collectively, our study defines the expression pattern of OPN in the posterior pole as a function of disease, and its local expression as a potential histopathologic biomarker of AMD.

Osteopontin Gene Polymorphisms Are Associated with Cardiovascular Risk Factors in Patients with Premature Coronary Artery Disease

Osteopontin (OPN) is considered a clinical predictor of cardiovascular disease. We aimed to evaluate the association of the OPN gene polymorphisms rs2728127 and rs11730582 with the development of premature coronary artery disease (pCAD), cardiovascular risk factors, and cardiometabolic parameters. We evaluated 1142 patients with pCAD and 1073 controls. Both polymorphisms were determined by Taqman assays. Similar allele and genotype frequencies were observed in both groups; additionally, an association of these polymorphisms with CAD and cardiometabolic parameters was observed in both groups. In patients with pCAD, the rs11730582 was associated with a high risk of hypoadiponectinemia (OR = 1.300, P _additive = 0.003), low risk of hypertension (OR = 0.709, P _{codominant 1} = 0.030), and low risk of having high non-HDL cholesterol (OR = 0.637, P _additive = 0.038). In the control group, the rs2728127 was associated with a low risk of fatty liver (OR = 0.766, P _additive = 0.038); while the rs11730582 was associated with a low risk of hypoadiponectinemia (OR = 0.728, P _dominant = 0.022), and risk of having elevated apolipoprotein B (OR = 1.400, P _dominant = 0.031). Our results suggest that in Mexican individuals, the rs11730582 and rs2728127 OPN gene polymorphisms are associated with some abnormal metabolic variables in patients with pCAD and controls.

Multiplex protein screening of biomarkers associated with major bleeding in patients with atrial fibrillation treated with oral anticoagulation

BACKGROUND

Oral anticoagulants (OAC) in patients with atrial fibrillation (AF) prevent thromboembolic events, but are associated with significant risk of bleeding.

OBJECTIVES

To explore associations between a wide range of biomarkers and bleeding risk in patients with AF on OAC.

METHOD

Biomarkers were analyzed in a random sample of 4200 patients, 204 cases with major bleedings, from ARISTOTLE. The replication cohort included 344 cases with major bleeding and 1024 random controls from RE-LY. Plasma samples obtained at randomization were analyzed by the Olink Proximity Extension Assay cardiovascular and inflammation panels and conventional immunoassays. The associations between biomarker levels and major bleeding over 1 to 3 years of follow-up were evaluated by random survival forest/Boruta analyses and Cox regression analyses to assess linear associations and hazard ratios for identified biomarkers.

RESULTS

Out of 268 proteins, nine biomarkers were independently associated with bleeding in both cohorts. In the replication cohort the linear hazard ratios (95% confidence intervals) per interquartile range were for these biomarkers: TNF-R1 1.748 (1.456, 2.098), GDF-15 1.653 (1.377, 1.985), EphB4 1.575 (1.320, 1.880), suPAR 1.548 (1.294, 1.851), OPN 1.476 (1.240, 1.757), OPG 1.397 (1.156, 1.688), TNF-R2 1.360 (1.144,1.616), cTnT-hs 1.232 (1.067, 1.423), and TRAIL-R2 1.202 (1.069, 1.351).

CONCLUSIONS

In patients with AF on OAC, GDF-15, cTnT-hs, and seven novel biomarkers were independently associated with major bleedings and reflect pathophysiologic processes of inflammation, apoptosis, oxidative stress, vascular calcification, coagulation, and fibrinolysis. Investigations of the utility of these markers to refine risk stratification and guide the management of patients at high risk of bleeding are warranted.

Osteocalcin, Osteopontin and RUNX2 Expression in Patients' Leucocytes with Arteriosclerosis

Introduction: Calcification is a highly relevant process in terms of development of cardiovascular diseases, and its prevention may be the key to prevent disease progression in patients. In this study we investigated the expression of osteocalcin (OC), osteopontin (OPN) and RUNX2 in patients’ leukocytes and their possible role as diagnostic markers for cardiovascular diseases. Materials and Methods: Leucocytes from 38 patients were collected in the Department of Surgery of Martin-Luther-University Halle, including 8 patients without arteriosclerotic disease (PAD−) and 30 patients with symptomatic arteriosclerotic disease (PAD+). Patients’ leucocytes, in vitro calcified human umbilical vein endothelial cells (HUVEC) and vascular smooth muscle cells (VSMC) were subjected to qPCR analyses with TaqMan probes, which are specific for OC, OPN and RUNX2. Additionally, the interaction between monocytes and calcified HUVEC and VSMC was investigated in adhesion assays. Results: The leucocytes obtained from patients with symptomatic arteriosclerotic disease (PAD+) demonstrated decreased mRNA level expression of Osteocalcin, while OPN and RUNX2 were significantly upregulated in comparison to asymptomatic patients. The induction of calcification in HUVEC and VSMC cells led to an increased expression of OC, OPN and RUNX2. Immunocytochemistry of calcified HUVEC and VSMC revealed stronger expression of OC, OPN and RUNX2 in calcified cells. Conclusion: To conclude, these data demonstrate that symptomatic arteriosclerotic disease has a correlation with OC, OPN and RUNX2. The biological rationale of OC, OPN and RUNX-2 remains not yet entirely understood for atherosclerotic disease, which means it needs further investigation.

Investigation of type 1 diabetes in NOD mice knockout for the osteopontin gene

OBJECTIVE

Type 1 diabetes onset is preceded by a pre-inflammatory stage leading to insulitis and followed by targeted destruction of the insulin-producing beta cells of the pancreas. Osteopontin (OPN) is a secreted phosphoprotein with cytokine properties, implicated in many physiological and pathological processes, including infection and autoimmunity. We have previously identified up-regulated osteopontin transcripts in the pancreatic lymph nodes of the NOD (Non-Obese Diabetic) mouse at the pre-diabetic stages. Investigating the underlined disease initiating mechanisms may well contribute to the development of novel preventive therapies. Our aim was to construct opn null mice in a NOD autoimmune-prone genetic background and address the pathogenic or protective role of the osteopontin molecule in the early stages of type 1 diabetes.

METHODS

We generated opn null mutant mice in a NOD genetic background by serial backcrossing to the existing C57BL/6 opn knockout strain. The presence of opn wild type or null alleles in the congenic lines was evaluated by PCR amplification. We used NOD opn-null mice to assess the phenotypic evolution of type 1 diabetes. The presence of OPN in the serum was evaluated by ELISA and by immunostaining on the mouse tissues. The primary gene structure of the NOD opn encoding gene and protein sequences were compared to the known alleles of other mouse strains. Evaluation of Single Nucleotide Polymorphisms (SNPs) variation between opn alleles of the opn gene is reported.

RESULTS

In the absence of OPN, type 1 diabetes is accelerated, suggesting a protective role of this cytokine on the insulin-producing cells of the pancreatic islets. Conversely, in the presence of the opn gene, an increase of the OPN protein in the serum of young NOD mice indicates that this molecule might be involved in the immune regulatory events taking place at early stages, prior to disease onset. Our data support that OPN acts as a positive regulator of the early islet autoimmune damage, possibly by a shift of the steady-state of T1D pathogenesis. We report that the OPN protein structure of the NOD/ShiLtJ strain corresponds to the a-type allele of the osteopontin gene. Comparative analysis of the single nucleotide polymorphisms between the a-type and b-type alleles indicates that the majority of variations are within the non-coding regions of the gene.

CONCLUSIONS

The construction of opn null mice in an autoimmune genetic background (NOD.B6.Cg-spp1^-/-) provides important tools for the study of the implication of the OPN in type 1 diabetes, offering the possibility to address the significance of this molecule as an early marker of the disease and as a therapeutic agent in preclinical studies.

Osteopontin: The Molecular Bridge between Fat and Cardiac-Renal Disorders

Osteopontin (OPN) is a multifaceted matricellular protein, with well-recognized roles in both the physiological and pathological processes in the body. OPN is expressed in the main organs and cell types, in which it induces different biological actions. During physiological conditioning, OPN acts as both an intracellular protein and soluble excreted cytokine, regulating tissue remodeling and immune-infiltrate in adipose tissue the heart and the kidney. In contrast, the increased expression of OPN has been correlated with the severity of the cardiovascular and renal outcomes associated with obesity. Indeed, OPN expression is at the “cross roads” of visceral fat extension, cardiovascular diseases (CVDs) and renal disorders, in which OPN orchestrates the molecular interactions, leading to chronic low-grade inflammation. The common factor associated with OPN overexpression in adipose, cardiac and renal tissues seems attributable to the concomitant increase in visceral fat size and the increase in infiltrated OPN⁺ macrophages. This review underlines the current knowledge on the molecular interactions between obesity and the cardiac–renal disorders ruled by OPN.

Osteopontin as novel biomarker for reversibility of pressure overload induced left ventricular hypertrophy

Aim: The aim of this study was to evaluate the prognostic value of osteopontin (OPN) as a marker for left ventricular (LV) hypertrophy and its reversibility after surgical aortic valve replacement (SAVR). Patients & methods: Echocardiographic data and OPN plasma levels of 149 consecutive patients undergoing SAVR were obtained preoperatively and 3 months postoperatively. OPN was measured by Quantikine Human OPN immunoassay. Results: There was a significant correlation between higher OPN plasma levels and lower LV-mass regression. In patients receiving SAVR combined with coronary artery bypass grafting, high OPN plasma levels were also an indicator for eccentric hypertrophy phenotype. Conclusion: OPN may be a useful indicator for LV hypertrophy phenotype and could have a prognostic value to estimate LV-mass regression after SAVR.

Serum tenascin-C is independently associated with increased major adverse cardiovascular events and death in individuals with type 2 diabetes: a French prospective cohort

AIMS/HYPOTHESIS

Tenascin-C (TN-C) is an extracellular matrix glycoprotein highly expressed in inflammatory and cardiovascular (CV) diseases. Serum TN-C has not yet been specifically studied in individuals with type 2 diabetes, a condition associated with chronic low-grade inflammation and increased CV disease risk. In this study, we hypothesised that elevated serum TN-C at enrolment in participants with type 2 diabetes would be associated with increased risk of death and major adverse CV events (MACE) during follow-up.

METHODS

We used a prospective, monocentric cohort of consecutive type 2 diabetes participants (the SURDIAGENE [SUivi Rénal, DIAbète de type 2 et GENEtique] cohort) with all-cause death as a primary endpoint and MACE (CV death, non-fatal myocardial infarction or stroke) as a secondary endpoint. We used a proportional hazard model after adjustment for traditional risk factors and the relative integrated discrimination improvement (rIDI) to assess the incremental predictive value of TN-C for these risk factors.

RESULTS

We monitored 1321 individuals (58% men, mean age 64 ± 11 years) for a median of 89 months. During follow-up, 442 individuals died and 497 had MACE. Multivariate Cox analysis showed that serum TN-C concentrations were associated with an increased risk of death (HR per 1 SD: 1.27 [95% CI 1.17, 1.38]; p < 0.0001) and MACE (HR per 1 SD: 1.23 [95% CI 1.13, 1.34]; p < 0.0001). Using TN-C concentrations on top of traditional risk factors, prediction of the risk of all-cause death (rIDI: 8.2%; p = 0.0006) and MACE (rIDI: 6.7%; p = 0.0014) improved significantly, but modestly.

CONCLUSIONS/INTERPRETATION

In individuals with type 2 diabetes, increased serum TN-C concentrations were independently associated with death and MACE. Therefore, including TN-C as a prognostic biomarker could improve risk stratification in these individuals.

Biomarkers of vascular calcification in serum

Over the last decades, the association between vascular calcification (VC) and all-cause/cardiovascular mortality, especially in patients with high atherogenic status, such as those with diabetes and/or chronic kidney disease, has been repeatedly highlighted. For over a century, VC has been noted as a passive, degenerative, aging process without any treatment options. However, during the past decades, studies confirmed that mineralization of the arteries is an active, complex process, similar to bone genesis and formation. The main purpose of this review is to provide an update of the existing biomarkers of VC in serum and develop the various pathogenetic mechanisms underlying the calcification process, including the pivotal roles of matrix Gla protein, osteoprotegerin, bone morphogenetic proteins, fetuin-a, fibroblast growth-factor-23, osteocalcin, osteopontin, osteonectin, sclerostin, pyrophosphate, Smads, fibrillin-1 and carbonic anhydrase II.

Pathophysiological and Genetic Aspects of Vascular Calcification

Recent evidence suggests that vascular calcification is an independent cardiovascular risk factor (CRF) of morbidity and mortality. New studies point out the existence of a complex physiopathological mechanism that involves inflammation, oxidation, the release of chemical mediators, and genetic factors that promote the osteochondrogenic differentiation of vascular smooth muscle cells (VSMC). This review will evaluate the main mechanisms involved in the pathophysiology and genetics modulation of the process of vascular calcification. Objective. A systematic review of the pathophysiology factors involved in vascular calcification and its genetic influence was performed. Methods. A systematic review was conducted in the Medline and PubMed databases and were searched for studies concerning vascular calcification using the keywords and studies published until 2020/01 in English. Inclusion Criteria. Studies in vitro, animal models, and humans. These include cohort (both retrospective and prospective cohort studies), case-control, cross-sectional, and systematic reviews. Exclusion Criteria. Studies before 2003 of the existing literature.

The biology of vascular calcification

Vascular calcification (VC), characterized by different mineral deposits (i.e., carbonate apatite, whitlockite and hydroxyapatite) accumulating in blood vessels and valves, represents a relevant pathological process for the aging population and a life-threatening complication in acquired and in genetic diseases. Similarly to bone remodeling, VC is an actively regulated process in which many cells and molecules play a pivotal role. This review aims at: (i) describing the role of resident and circulating cells, of the extracellular environment and of positive and negative factors in driving the mineralization process; (ii) detailing the types of VC (i.e., intimal, medial and cardiac valve calcification); (iii) analyzing rare genetic diseases underlining the importance of altered pyrophosphate-dependent regulatory mechanisms; (iv) providing therapeutic options and perspectives.

Association of Circulating Osteopontin Levels With Lower Extremity Arterial Disease in Subjects With Type 2 Diabetes Mellitus: A Cross-Sectional Observational Study

Osteopontin (OPN) is involved in the atherosclerotic and inflammatory process. In this article, we examined the relationship between circulating OPN levels with lower extremity arterial disease (LEAD) in individuals with type 2 diabetes mellitus (T2DM). Seventy individuals with T2DM and 66 individuals without T2DM were recruited. Diagnosis of LEAD was based on the absence of triphasic waveform on the pedal arteries. Plasma OPN levels were determined by Luminex Multiplex immunoassay. LEAD was present in 34 (48.6%) patients with T2DM. In the diabetes cohort, individuals with LEAD had higher plasma OPN concentrations than those without LEAD (geometric mean [95% confidence intervals]; 43.4 [37.5-50.4] vs 26.1 [22.9-29.8] ng/mL, respectively, P < .001). Multivariable analysis showed that presence of LEAD independently associated with higher OPN levels in subjects with T2DM, with marginal statistical significance ( P = .049). In both cohorts, plasma OPN concentrations were negatively associated with ankle-brachial index values ( P < .05). In the total sample, there was a gradual increase of OPN levels across subgroups with triphasic, biphasic, and monophasic/blunted waveforms ( P < .001). In conclusion, plasma OPN levels are associated with the presence and severity of LEAD in subjects with T2DM. Further studies are needed to investigate the role of OPN in the pathogenesis and progression of LEAD.

Osteopontin in Vascular Disease

Inflammatory cytokines are necessary for an acute response to injury and the progressive healing process. However, when this acute response does not resolve and becomes chronic, the same proteins that once promoted healing then contribute to chronic inflammatory pathologies, such as atherosclerosis. OPN (Osteopontin) is a secreted matricellular cytokine that signals through integrin and CD44 receptors, is highly upregulated in acute and chronic inflammatory settings, and has been implicated in physiological and pathophysiologic processes. Evidence from the literature suggests that OPN may fit within the Goldilocks paradigm with respect to cardiovascular disease, where acute increases are protective, attenuate vascular calcification, and promote postischemic neovascularization. In contrast, chronic increases in OPN are clinically associated with an increased risk for a major adverse cardiovascular event, and OPN expression is a strong predictor of cardiovascular disease independent of traditional risk factors. With the recent finding that humans express multiple OPN isoforms as the result of alternative splicing and that these isoforms have distinct biologic functions, future studies are required to determine what OPN isoform(s) are expressed in the setting of vascular disease and what role each of these isoforms plays in vascular disease progression. This review aims to discuss our current understanding of the role(s) of OPN in vascular disease pathologies using evidence from in vitro, animal, and clinical studies. Where possible, we discuss what is known about OPN isoform expression and our understanding of OPN isoform contributions to cardiovascular disease pathologies.

Osteopontin for Early Detection of Microvascular and Macrovascular Type 1 Diabetic Complication

AIM

To evaluate the relationship between osteopontin and diabetes complication in type 1 diabetic patient.

PATIENTS AND METHODS

Seventy types 1 diabetic and 60 healthy volunteers were studied. Full history, examination, laboratory tests of glycosylated haemoglobin (HbA1c), serum lipids {cholesterol, triglyceride (Tg), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein - cholesterol (LDL-c)}, oxidised low-density lipoprotein (OxLDL), Osteopontin and urinary microalbuminuria (albumin/creatinine ratio) were done. Image study in the form of a carotid intimal medial thickness (cIMT) and aortic intimal medial thickness (aIMT), renal doppler for resistivity index was also done for all participant included in the study.

RESULTS

Urinary albumin/creatinine ratio, lipid profile, osteopontin, cIMT and aIMT were higher in people with diabetes. Osteopontin was higher in people with diabetes with positive microalbuminuria and cIMT. Systolic blood pressure, microalbuminuria and cIMT had a positive correlation with osteopontin in people with diabetes. Stepwise multiple regression analysis showed that osteopontin had a significant correlation with cIMT. Receiver operating characteristic (ROC) curve showed that the cut off value of Osteopontin for detection of cIMT was > 60 with a specificity of 100% and sensitivity 80.5%, while that of albumin/creatinine ratio was > 64 with a specificity of 66.7 and sensitivity of 92.3.

CONCLUSION

Osteopontin is higher in type 1 diabetics and is useful for early detection of diabetic microvascular and macrovascular complication.

Calcification biomarkers and vascular dysfunction in obesity and type 2 diabetes: influence of oral hypoglycemic agents

Vascular aging in obesity and type 2 diabetes (T2D) is associated with progressive vascular calcification, an independent predictor of morbidity and mortality. Pathways for vascular calcification modulate bone matrix deposition, thus regulating calcium deposits. We investigated the association between biomarkers of vascular calcification and vasodilator function in obesity or T2D, and whether antidiabetic therapies favorably impact those markers. Circulating levels of proteins involved in vascular calcification, such as osteopontin (OPN), osteoprotegerin (OPG), regulated on activation, normal T cell expressed and secreted (RANTES), and fetuin-A were measured in lean subjects, individuals with metabolically healthy obesity (MHO), and patients with metabolically unhealthy obesity (MUO) or T2D. Vasodilator function was assessed by infusion of ACh and sodium nitroprusside (SNP). Circulating levels of OPN were higher in the MUO/T2D group than in lean subjects (P < 0.05); OPG and RANTES were higher in MUO/T2D group than in the other groups (both P < 0.001); fetuin-A was not different between groups (P > 0.05); vasodilator responses to either ACh or SNP were impaired in both MUO/T2D and MHO compared with lean subjects (all P < 0.001). In patients with T2D who were enrolled in the intervention trial, antidiabetic treatment with glyburide, metformin, or pioglitazone resulted in a significant reduction of circulating OPG (P = 0.001), without changes in the other biomarkers and vasodilator responses (all P > 0.05). In conclusion, obese patients with MUO/T2D have elevated circulating OPN, OPG, and RANTES; in these patients, antidiabetic treatment reduces only circulating OPG. Further study is needed to better understand the mechanisms of vascular calcifications in obesity and diabetes.

Correlation of plasma osteopontin and osteocalcin with lower renal function in dental patients with carotid artery calcification and tooth loss

OBJECTIVES

To investigate plasma osteopontin (OPN) and osteocalcin (OCN) levels in dental patients with carotid artery calcification (CAC) and determine the correlations between these proteins and renal function and tooth loss.

METHODS

The health parameters and number of teeth of 99 participants were recorded. Panoramic radiographs were taken for CAC evaluation, and OPN and OCN levels were measured.

RESULTS

None of the participants had overt kidney disease, and 14 (14.14%) had CAC. The age, sex, and health profiles of patients with CAC were not different from those without CAC. The OPN and OCN levels in participants with CAC were higher than in those without (p = 0.026 and p = 0.025, respectively). The OPN levels were correlated with the estimated glomerular filtration rate (eGFR) (p = 0.021) and tooth loss (p = 0.027). The OCN levels were correlated with the eGFR (p = 0.002), tooth loss (p = 0.023), blood urea nitrogen (p = 0.040), and creatinine levels (p = 0.031). The median tooth loss in individuals with an eGFR <60 mL/min/1.73 m² was higher than that of individuals with an eGFR ≥60 mL/min/1.73 m² (p = 0.033). In individuals with CAC, tooth loss correlated more strongly with the eGFR, and the correlation between OPN and OCN levels was more apparent.

CONCLUSION

Dental patients with CAC and increased tooth loss have a greater tendency for decreased renal function, which may be associated with OPN and OCN; thus, these patients should be referred for investigation.

Impaired bone matrix glycoprotein pattern is associated with increased cardio-metabolic risk profile in patients with type 2 diabetes mellitus

PURPOSE

Osteopontin (OPN), osteoprotegerin (OPG) and osteocalcin (OC) are matrix glycoproteins which mediate bone mineralization; moreover, their effects on glucose/insulin homeostasis have recently been demonstrated. Higher circulating OPN and OPG levels have been associated with the presence of insulin resistance, atherosclerosis and coronary heart disease. No data are available on contextual changes of these markers in type 2 diabetes mellitus (T2DM). Therefore, aims of this study were to evaluate serum OPN, OPG and OC levels in T2DM patients and their clinical correlates.

METHODS

We recruited 83 consecutive T2DM patients referring to our diabetes outpatient clinics at Sapienza, University of Rome, and 71 non-diabetic sex and age-comparable subjects as a control group. Study population underwent metabolic characterization and carotid ultrasound for intima-media thickness measurement. Plasma OPN, OPG and OC were measured by MILLIPLEX Multiplex Assays Luminex.

RESULTS

T2DM patients had significantly higher circulating OPN and OPG levels than controls (14.3 ± 13.6 vs 10.6 ± 13.7 ng/ml p < 0.001, 0.70 ± 0.60 vs 0.54 ± 4.1 ng/ml, p = 0.02) while OC levels were similar in the two cohorts (6.35 ± 5.8 vs 7.80 ± 7.0 ng/ml, p = n.s). OPN and OPG positively correlated with greater systolic blood pressure (SBP) values, HOMA-IR and HOMA-β, and with the presence of dyslipidemia and carotid atherosclerosis. The association between greater OPN and OPG levels and SBP was independent from possible confounders (both p = 0.01).

CONCLUSIONS

Circulating OPN and OPG levels are increased in T2DM patients and identify a particularly unfavourable metabolic profile, mostly expressed by higher SBP. Bone peptides may represent novel markers of vascular stress and accelerated atherosclerosis in diabetes, constituting a possible tool for cardiovascular risk stratification in diabetes.

High serum osteopontin levels are associated with prevalent fractures and worse lipid profile in post-menopausal women with type 2 diabetes

PURPOSE

Patients with type 2 diabetes (T2DM) have increased fracture risk. Osteopontin (OPN) is a protein involved in bone remodeling and inflammation. The aim of this study was to evaluate the association of OPN with fracture prevalence and with metabolic parameters in post-menopausal women with T2DM.

METHODS

Sixty-four post-menopausal women with T2DM (age 67.0 ± 7.8 years, diabetes duration 8.9 ± 6.7 years), enrolled in a previous study, were followed up (3.6 ± 0.9 years). Previous fragility fractures were recorded. The FRAX score (without BMD) was calculated and biochemical parameters (plasma glucose, HbA1c, lipid profile and renal function) were assessed. Serum 25OH-vitamin D, calcium, PTH and OPN were evaluated at baseline. The association between OPN and fracture prevalence at baseline was evaluated by a logistic model.

RESULTS

OPN levels were higher in patients with previous fractures (n.25) than in patients without previous fractures at baseline (n.39) (p = 0.006). The odds of having fractures at baseline increased by 6.7 (1.9-31.4, 95% CI, p = 0.007) for each increase of 1 ng/ml in OPN levels, after adjustment for vitamin D and HbA1c levels. Fracture incidence was 4.7%. Higher OPN associated with a decrease in HDL-cholesterol (p = 0.048), after adjustment for age, basal HDL-cholesterol, basal and follow-up HbA1c and follow-up duration. 25OH-vitamin D associated with an increase in FRAX-estimated probability of hip fracture at follow-up (p = 0.029), after adjustment for age, 25OH-vitamin D and time.

CONCLUSIONS

In post-menopausal women with T2DM, OPN might be a useful marker of fracture and worse lipid profile.

Cell-Matrix Interactions and Matricrine Signaling in the Pathogenesis of Vascular Calcification

Vascular calcification is a complex pathological process occurring in patients with atherosclerosis, type 2 diabetes, and chronic kidney disease. The extracellular matrix, via matricrine-receptor signaling plays important roles in the pathogenesis of calcification. Calcification is mediated by osteochondrocytic-like cells that arise from transdifferentiating vascular smooth muscle cells. Recent advances in our understanding of the plasticity of vascular smooth muscle cell and other cells of mesenchymal origin have furthered our understanding of how these cells transdifferentiate into osteochondrocytic-like cells in response to environmental cues. In the present review, we examine the role of the extracellular matrix in the regulation of cell behavior and differentiation in the context of vascular calcification. In pathological calcification, the extracellular matrix not only provides a scaffold for mineral deposition, but also acts as an active signaling entity. In recent years, extracellular matrix components have been shown to influence cellular signaling through matrix receptors such as the discoidin domain receptor family, integrins, and elastin receptors, all of which can modulate osteochondrocytic differentiation and calcification. Changes in extracellular matrix stiffness and composition are detected by these receptors which in turn modulate downstream signaling pathways and cytoskeletal dynamics, which are critical to osteogenic differentiation. This review will focus on recent literature that highlights the role of cell-matrix interactions and how they influence cellular behavior, and osteochondrocytic transdifferentiation in the pathogenesis of cardiovascular calcification.

Association between bone metabolism regulators and arterial stiffness in type 2 diabetes patients

BACKGROUND AND AIM

Osteopontin (OPN), osteonectin (ON) and osteocalcin (OC) play an important role in the development of vascular calcifications, but it is unclear whether these bone metabolism regulators contribute to the development of arterial stiffness in type 2 diabetes patients. We therefore aim to determine the relationship between plasma concentrations of OPN, ON, OC and arterial stiffness in type 2 diabetes patients.

METHODS

Cross-sectional study of 1003 type 2 diabetes patients included in the Second Manifestations of ARTerial disease (SMART)-cohort. Generalized linear models were used to evaluate the relation between plasma levels of OPN, ON and OC and arterial stiffness as measured by pulse pressure (PP), ankle-brachial index (ABI) (≥0.9), carotid artery distension and an arterial stiffness summary score. Analyses were adjusted for age, sex, kidney function, diabetes duration and diastolic blood pressure. Higher OPN plasma levels were significantly related to a lower ABI (β-0.013; 95%CI -0.024 to -0.002) and a higher arterial stiffness summary score (OR1.24; 95%CI 1.03-1.49). OPN levels were not related to PP (β 0.59; 95%CI -0.63-1.81) or absolute carotid artery distention (β -7.03; 95%CI -20.00-5.93). ON and OC plasma levels were not related to any of the arterial stiffness measures.

CONCLUSION

Only elevated plasma levels of OPN are associated with increased arterial stiffness in patients with type 2 diabetes as measured by the ankle-brachial index and arterial stiffness summary score. These findings indicate that OPN may be involved in the pathophysiology of arterial stiffness and call for further clinical investigation.

The multiple functions and mechanisms of osteopontin

Osteopontin (OPN) is a highly phosphorylated glycophosphoprotein having acidic characteristics and rich in aspartic acid. OPN, a multifunctional protein, has important functions on cardiovascular diseases, cancer, diabetes and kidney stone diseases and in the process of inflammation, biomineralization, cell viability and wound healing. Osteopontin acts on organisms by playing a key role in secretion levels of interleukin-10 (IL-10), interleukin-12 (IL-12), interleukin-3 (IL-3), interferon-γ (IFN-γ), integrin αvB3, nuclear factor kappa B (NF-kB), macrophage and T cells, regulating the osteoclast function and affecting CD44 receptors. The aim of the present review is to address majority of different functions of OPN protein which are known, suspected or suggested through the data obtained about this protein yet.

Osteopontin as a marker of vasculopathy in pediatric patients with type 1 diabetes mellitus: Relation to vascular structure

BACKGROUND

Type 1 diabetes mellitus (T1DM) is associated with serious micro-vascular and macro-vascular complications. Osteopontin (OPN) has emerged as a strong predictor of incipient diabetic nephropathy and a first-ever cardiovascular event in adults with T1DM. OPN is linked to coronary atherosclerosis in type 2 diabetes. The aim of the study was to test the hypothesis that OPN could be a potential marker for micro-vascular complications in children and adolescents with T1DM and we assessed its relation to carotid and aortic intima media thickness (CIMT and AIMT) as non-invasive index for subclinical atherosclerosis.

METHODS

Eighty patients with T1DM ≤18 years were divided into 2 groups according to the presence of micro-vascular complications and compared with 40 age- and sex-matched healthy controls. Fasting blood glucose, high sensitivity C-reactive protein (hs-CRP), HbA1c, urinary albumin creatinine ratio (UACR), OPN, CIMT, and AIMT were assessed.

RESULTS

Both CIMT and AIMT were significantly higher in patients with and without micro-vascular complications compared with healthy controls (P < .001). OPN concentrations were significantly elevated in all diabetic patients compared with controls (P = .002). OPN was also significantly higher in patients with micro-vascular complications than patients without (P < .001) but levels were comparable among those without complications and controls (P = .322). Receiver operating characteristic curve analysis revealed that OPN cut-off value 90 ng/mL could differentiate patients with and without micro-vascular complications with 81.7% sensitivity and 95.8% specificity. Significant positive correlations were found between OPN and HbA1c, UACR, CIMT, and AIMT.

CONCLUSIONS

OPN could be considered a marker of vasculopathy and subclinical atherosclerosis in pediatric T1DM.

Bone markers and cardiovascular risk in type 2 diabetes patients

Background

Vascular calcifications are associated with a three- to fourfold increased risk of cardiovascular disease (CVD) and are highly prevalent in type 2 diabetes patients. Emerging evidence indicates that vascular calcification is a process of active bone formation regulated by stimulators and inhibitors of calcification. Therefore, this study aimed to evaluate whether six bone markers are associated with CVD risk in patients with type 2 diabetes.

Methods

We used data of a case-cohort study, nested in the EPIC-NL cohort, comprising 134 CVD cases and a random subcohort of 218 participants, all with type 2 diabetes at baseline. Six bone markers (osteocalcin, osteopontin, osteonectin, osteoprotegerin, alkaline phosphatase and sclerostin) were measured in baseline plasma samples with multiplex assays and information on CVD events was obtained. The association of bone makers with CVD risk was evaluated using Cox proportional hazard analyses.

Results

Higher concentrations of plasma osteopontin were associated (p_trend < 0.01) with an increased CVD risk with a hazard ratio of 2.00 (95%-CI 1.20–3.35) for the highest versus the lowest quartile in a multivariable adjusted model. The other bone markers were not associated with CVD risk.

Conclusions

Higher osteopontin concentrations were associated with an increased CVD risk in type 2 diabetes patients. No consistent associations were found for the other five bone markers and risk of CVD in type 2 diabetes patients.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0691-2) contains supplementary material, which is available to authorized users.

The potential role of the osteopontin-osteocalcin-osteoprotegerin triad in the pathogenesis of prediabetes in humans

AIMS

To examine the relationship between hormones involved in bone remodeling and glucose metabolism alterations in prediabetes.

METHODS

Individuals (n = 43) with NGT (BMI = 31.1 ± 1.1 kg/m²) and individuals (n = 79) with impaired glucose regulation (IGR) (BMI = 31.9 ± 1.2 kg/m²) including subjects with IFG, IGT, and IFG-IGT underwent OGTT and DXA. Osteopontin (OPN), osteocalcin (OCN), osteoprotegerin (OPG), and PTH levels were measured at fasting. Beta-cell function was calculated using C-peptide deconvolution. Dynamic indexes of insulin sensitivity were calculated from OGTT. A subgroup underwent to a euglycemic hyperinsulinemic clamp with 3-³H-glucose to estimate the endogenous glucose production (EGP) and insulin-mediated body glucose disposal (TGD/SSPI).

RESULTS

OPN was higher in IGR compared to NGT (5.3 ± 0.5 vs. 3.3 ± 0.2 μg/mL; p = 0.008) and in isolated IGT compared to IFG and IFG-IGT (6.3 ± 0.5 vs. 4.5 ± 0.3 and 5.4 ± 0.5 μg/mL; p = 0.02). OCN was similar in IFG and NGT but lower in IGT and IFG-IGT compared to NGT (7.2 ± 0.3 and 5.4 ± 0.2 vs. 8.3 ± 0.3 ng/mL; p < 0.01). OPN was positively correlated with HbA1c, fasting and 2 h plasma glucose and PTH. OCN was negatively correlated with body fat, 2 h plasma glucose, insulin and positively correlated with Stumvoll index. OPG correlated with TGD/SSPI (r = - 0.29; p < 0.05), EGP, and hepatic insulin resistance index in IGR (r = 0.51, r = 0.43; p < 0.01). There was no correlation between PTH and insulin sensitivity or Beta-cell function parameters.

CONCLUSIONS

In prediabetes, hormones known to be involved in bone remodeling may affect glucose metabolism before overt T2DM occurs with tissue-specific mechanisms.

Plasma osteopontin concentration is elevated in patients with coronary bare metal stent restenosis

OBJECTIVE

Osteopontin is a component of atherosclerotic lesions, secreted by monocytes, macrophages and endothelial and vascular smooth muscle cells, which together are responsible for neointimal proliferation. We examined whether elevated plasma osteopontin concentration was associated with in-stent restenosis in patients with coronary artery disease.

SUBJECTS AND METHODS

We enrolled 91 patients who underwent coronary artery stenting, and 60 control patients with normal findings on coronary angiography, between June 2012 and September 2013. For patients with stents, we measured plasma osteopontin concentration at the first follow-up coronary angiogram. For controls, plasma osteopontin concentration was measured at the time of angiography.

RESULTS

Of the 91 patients who had undergone coronary artery stenting, 31 (34.1%) had developed in-stent restenosis and the mean time passed to control coronary angiography was 36.7 months (±SD 35.1 months). Mean plasma osteopontin concentration in this group was 2721.4 ± 1787.8 pg/ml, significantly higher than the 60 patients (65.9%) with no in-stent restenosis (1770.4 ± 1208.2 pg/ml, p = .011) and the 60 patients with a normal coronary angiogram (1572.4 ± 904.8 pg/ml, p = .002). There was no significant difference in mean osteopontin concentration between the patients with no in-stent restenosis and the control group (p = .312).

CONCLUSIONS

Elevated plasma osteopontin concentration is associated with in-stent stenosis in patients with coronary artery disease. Further studies will be needed to establish whether osteopontin can predict in-stent restenosis and guide clinical management strategies.

Pregnancy history, coronary artery calcification and bone mineral density in menopausal women

OBJECTIVE

This study examined relationships, by pregnancy histories, between bone mineral density (BMD) and coronary artery calcification (CAC) in postmenopausal women.

METHODS

Forty women identified from their medical record as having pre-eclampsia (PE) were age/parity-matched with 40 women having a normotensive pregnancy (NP). Vertebral (T4-9) BMD and CAC were assessed by quantitative computed tomography in 73 (37 with PE and 36 with NP) of the 80 women. Analyses included linear regression using generalized estimating equations.

RESULTS

Women averaged 59 years of age and 35 years from the index pregnancy. There were no significant differences in cortical, trabecular or central BMD between groups. CAC was significantly greater in the PE group (p = 0.026). In multivariable analysis, CAC was positively associated with cortical BMD (p = 0.001) and negatively associated with central BMD (p = 0.036). There was a borderline difference in the association between CAC and central BMD by pregnancy history (interaction, p = 0.057).

CONCLUSIONS

Although CAC was greater in women with a history of PE, vertebral BMD did not differ between groups. However, both cortical and central BMD were associated with CAC. The central BMD association was marginally different by pregnancy history, suggesting perhaps differences in underlying mechanisms of soft tissue calcification.

Mechanism of genistein regulating the differentiation of vascular smooth muscle cells into osteoblasts via the OPG/RANKL pathway

Objective

The present study aimed to investigate the mechanism of genistein, a tyrosine kinase inhibitor, regulating the differentiation of vascular smooth muscle cells (VSMCs) into osteoblasts via the OPG/RANKL (Osteoprotegerin/Receptor Activator of Nuclear Factor-κB Ligand) pathway.

Methods

The mouse VSMCs were isolated, purified and cultured. We constructed the LV5-Tnfrsf11b overexpression lentiviral vector and LV3-OPG-309 interference lentiviral vector. The OPG overexpression was induced and the growth of VSMCs infected with the lentiviral vector was observed. The VSMC calcification and control group were treated with different doses of genistein. The mRNA and protein expression levels of OPG, α-SM-actin (smooth muscle actin), ALP (alkaline phosphatase) and OPN (osteopontin) were detected in VSMCs after treatment using RT-PCR and Western Blot.

Result

We induced OPG overexpression and performed lentiviral vector infection of the VSMCs to suppress OPG expression, respectively, which was followed by treatment with genistein. The results showed that the relative expression of OPG was the highest in the VSMC calcification +genistein +OPG overexpression-inducing treatment group. It was the lowest in the VSMC calcification +OPG expression-suppressing treatment group. The relative expression of ALP was the highest in the VSMC calcification +OPG expression-suppressing treatment group, and the lowest in the VSMCs+genistein treatment group.

Conclusion

OPG gene plays an important regulatory role in the growth of VSMCs, by suppressing the calcification of VSMCs. Genistein could regulate the differentiation of VSMCs into osteoblasts via the OPG/RANKL pathway in a dose-dependent manner.

Osteopontin as a discriminating marker for pancreatic cancer and chronic pancreatitis

INTRODUCTION

We analyzed concentrations of osteopontin (OPN) in patients with pancreatic ductal adenocarcinoma (PDAC) in order to determine firstly whether it is useful to distinguish between PDAC patients and those with chronic non-hereditary pancreatitis (CP) and type 2 diabetes mellitus (T2DM), and secondly whether OPN concentrations depend on the PDAC stage.

METHODS

Groups consisting of 64 patients with PDAC, 71 with CP, 67 with T2DM and 48 healthy controls (CON) were enrolled in the study. Controls were compared with regard to levels of OPN, oxidative stress markers, conventional tumor markers and other biochemical parameters.

RESULTS

Levels of OPN were higher in patients with PDAC compared with CP patients (P< 0.001), T2DM (P< 0.001) and CON (P< 0.001). There were increased OPN levels in CP patients in comparison with T2DM (P< 0.001) and CON (P< 0.001). Patients with PDAC in stage IV had higher OPN levels than PDAC patients in stage III (P< 0.01). There was no difference in OPN levels of PDAC patients in stage III compared to patients in stage II.

CONCLUSION

Our pilot study demonstrates the usefulness of estimating OPN levels to differentiate between pancreatic cancer and chronic pancreatitis. Higher OPN levels over 102 ng/ml could be a potential diagnostic biomarker for pancreatic cancer.

The Role of Osteopontin in the Pathogenesis and Complications of Type 1 Diabetes Mellitus in Children

OBJECTIVE

Type 1 diabetes mellitus (T1DM) is the most common chronic metabolic disorder of childhood and adolescence. Osteopontin plays a significant role in the development and progression of several autoimmune diseases. Moreover, osteopontin promotes adipose tissue inflammation, dysfunction, and insulin resistance. To investigate the levels of serum osteopontin in pediatric patients with T1DM and to explore if these levels have a role in the prediction of diabetes complications.

METHODS

This was a case-control study conducted at the Endocrinology unit of the Children's Hospital of Zagazig University in Egypt, from October 2014 to December 2015. Sixty patients with T1DM and 60 healthy subjects were enrolled. A detailed medical history was taken from all patients/parents. A full clinical examination including ophthalmoscopy was performed on all patients. Fasting blood glucose, hemoglobin A1c (HbA1c), urine albumin/creatinine ratio, and serum osteopontin levels were also determined in all subjects.

RESULTS

Patients with T1DM had significantly higher serum osteopontin levels compared with controls (mean ± standard deviation: 13.7±3.4 μg/L vs. 8.9±2.9 μg/L, p<0.001). Also, serum osteopontin concentrations were higher in patients with microalbuminuria than in patients with normal albumin excretion rate and in the control group. Similarly, those who had retinal disease had higher osteopontin concentrations than those without (16.8±2 vs. 12.4±3 mg/L; p=0.005). Serum osteopontin levels correlated with a diagnosis of T1DM, and in diabetic patients, correlated with higher systolic and diastolic blood pressure, body mass index values and with lower high density lipoprotein values, diagnosis of retinopathy, and microalbuminuria. No correlation was found between osteopontin levels and HbA1c, insulin dose, co-medications, and diabetes duration in T1DM patients. The association between high osteopontin levels and T1DM was independent from all confounders.

CONCLUSION

This study shows that increased osteopontin levels are independently associated with T1DM in pediatric patients and supports the hypothesis that osteopontin may have a role in the prediction of microvascular diabetes complications.

AGEs induce ectopic endochondral ossification in intervertebral discs

Ectopic calcifications in intervertebral discs (IVDs) are known characteristics of IVD degeneration that are not commonly reported but may be implicated in structural failure and dysfunctional IVD cell metabolic responses. This study investigated the novel hypothesis that ectopic calcifications in the IVD are associated with advanced glycation end products (AGEs) via hypertrophy and osteogenic differentiation. Histological analyses of human IVDs from several degeneration stages revealed areas of ectopic calcification within the nucleus pulposus and at the cartilage endplate. These ectopic calcifications were associated with cells positive for the AGE methylglyoxal-hydroimidazolone-1 (MG-H1). MG-H1 was also co-localised with Collagen 10 (COL10) and Osteopontin (OPN) suggesting osteogenic differentiation. Bovine nucleus pulposus and cartilaginous endplate cells in cell culture demonstrated that 200 mg/mL AGEs in low-glucose media increased ectopic calcifications after 4 d in culture and significantly increased COL10 and OPN expression. The receptor for AGE (RAGE) was involved in this differentiation process since its inhibition reduced COL10 and OPN expression. We conclude that AGE accumulation is associated with endochondral ossification in IVDs and likely acts via the AGE/RAGE axis to induce hypertrophy and osteogenic differentiation in IVD cells. We postulate that this ectopic calcification may play an important role in accelerated IVD degeneration including the initiation of structural defects. Since orally administered AGE and RAGE inhibitors are available, future investigations on AGE/RAGE and endochondral ossification may be a promising direction for developing non-invasive treatment against progression of IVD degeneration.

ANGPTL2 is associated with an increased risk of cardiovascular events and death in diabetic patients

AIMS/HYPOTHESIS

A high serum angiopoietin-like 2 (ANGPTL2) concentration is an independent risk factor for developing diabetes and is associated with insulin resistance and atherosclerosis. In this work, we have examined the impact of serum ANGPTL2 on improving cardiovascular (CV) risk stratification in patients with type 2 diabetes.

METHODS

A prospective, monocentric cohort of consecutive type 2 diabetes patients (the SURDIAGENE cohort; total of 1353 type 2 diabetes patients; 58% men, mean ± SD age 64 ± 11 years) was followed for a median of 6.0 years for death as primary endpoint and major adverse CV events (MACE; i.e. CV death, myocardial infarction or stroke) as a secondary endpoint. Patients with end-stage renal disease, defined as a requirement for dialysis or a history of kidney transplantation, were excluded. Patients were grouped into quartiles according to ANGPTL2 concentrations at inclusion: <11.2 (Q1), 11.2-14.7 (Q2), 14.8-19.5 (Q3) or >19.5 (Q4) ng/ml.

RESULTS

During follow up, 367 patients (representing 4.5% of the total person-years) died and 290 patients (representing 3.7% of the total person-years) presented with MACE. Both the survival and MACE-free survival rates were significantly different between ANGPTL2 quartiles (logrank 82.12, p < 0.0001 for death; and logrank 65.14, p < 0.0001 for MACE). Patients with ANGPTL2 concentrations higher than 19.5 ng/ml (Q4) had a significantly higher risk of death and MACE than those with ANGPTL2 levels of 19.5 ng/ml or less (Q1-3) (HR for death 2.44 [95% CI 1.98, 3.00], p < 0.0001; HR for MACE 2.43 [95% CI 1.92, 3.06], p < 0.0001) after adjustment for sex, age and established CV risk factors. Using ANGPTL2 concentrations, prediction of the risk of mortality, as assessed by integrated discrimination improvement (IDI), was significantly improved (IDI 0.006 ± 0.002, p = 0.0002).

CONCLUSIONS/INTERPRETATION

In patients with type 2 diabetes, serum ANGPTL2 concentrations were independently associated with death and MACE. Therefore, ANGPTL2 is a promising candidate biomarker for improving risk stratification in type 2 diabetes patients, and may prove to be a valuable therapeutic target.

Bone mineral density is associated with left ventricular diastolic function in women

BACKGROUND

Low bone mineral density (BMD) and left ventricular (LV) diastolic function are associated with heart failure. However, little is known about the association between BMD and LV diastolic function.

HYPOTHESIS

BMD is independently related to LV diastolic function in women.

METHODS

We conducted a cross-sectional study of 432 women. Brachial-ankle pulse wave velocity (baPWV) and BMD measurements were performed. LV diastolic function and structure were assessed by echocardiographic examination.

RESULTS

BaPWV and the percentage of LV diastolic dysfunction increased with progressive bone loss. Moreover, partial correlation analysis demonstrated that BMD at spine L2-4 and at femoral neck were correlated with baPWV and LV diastolic function parameters after adjusting covariates. Multivariate logistic regression analysis revealed that osteoporosis was independently associated with LV diastolic dysfunction in women.

CONCLUSIONS

Osteoporosis is independently associated with LV diastolic dysfunction in women. A prospective study is needed to elucidate the effects of BMD on cardiac function in women.

Increased Obesity-Associated Circulating Levels of the Extracellular Matrix Proteins Osteopontin, Chitinase-3 Like-1 and Tenascin C Are Associated with Colon Cancer

BACKGROUND

Excess adipose tissue represents a major risk factor for the development of colon cancer with inflammation and extracellular matrix (ECM) remodeling being proposed as plausible mechanisms. The aim of this study was to investigate whether obesity can influence circulating levels of inflammation-related extracellular matrix proteins in patients with colon cancer (CC), promoting a microenvironment favorable for tumor growth.

METHODS

Serum samples obtained from 79 subjects [26 lean (LN) and 53 obese (OB)] were used in the study. Enrolled subjects were further subclassified according to the established diagnostic protocol for CC (44 without CC and 35 with CC). Anthropometric measurements as well as circulating metabolites and hormones were determined. Circulating concentrations of the ECM proteins osteopontin (OPN), chitinase-3-like protein 1 (YKL-40), tenascin C (TNC) and lipocalin-2 (LCN-2) were determined by ELISA.

RESULTS

Significant differences in circulating OPN, YKL-40 and TNC concentrations between the experimental groups were observed, being significantly increased due to obesity (P<0.01) and colon cancer (P<0.05). LCN-2 levels were affected by obesity (P<0.05), but no differences were detected regarding the presence or not of CC. A positive association (P<0.05) with different inflammatory markers was also detected.

CONCLUSIONS

To our knowledge, we herein show for the first time that obese patients with CC exhibit increased circulating levels of OPN, YKL-40 and TNC providing further evidence for the influence of obesity on CC development via ECM proteins, representing promising diagnostic biomarkers or target molecules for therapeutics.

Label-Free Quantitative Proteomics Reveals Differences in Molecular Mechanism of Atherosclerosis Related and Non-Related to Chronic Kidney Disease

The major cause of mortality in patients with chronic kidney disease (CKD) is atherosclerosis related to traditional and non-traditional risk factors. However, the understanding of the molecular specificity that distinguishes the risk factors for classical cardiovascular disease (CVD) and CKD-related atherosclerosis (CKD-A) is far from complete. In this study we investigated the disease-related differences in the proteomes of patients with atherosclerosis related and non-related to CKD. Plasma collected from patients in various stages of CKD, CVD patients without symptoms of kidney dysfunction, and healthy volunteers (HVs), were analyzed by a coupled label-free and mass spectrometry approach. Dysregulated proteins were confirmed by an enzyme-linked immunosorbent assay (ELISA). All proteomic data were correlated with kidney disease development and were subjected to bioinformatics analysis. One hundred sixty-two differentially expressed proteins were identified. By directly comparing the plasma proteomes from HVs, CKD, and CVD patients in one study, we demonstrated that proteins involved in inflammation, blood coagulation, oxidative stress, vascular damage, and calcification process exhibited greater alterations in patients with atherosclerosis related with CKD. These data indicate that the above nontraditional risk factors are strongly specific for CKD-A and appear to be less essential for the development of "classical" CVD.

Increased circulating osteopontin levels in adult patients with type 1 diabetes mellitus and association with dysmetabolic profile

OBJECTIVE

Osteopontin (OPN) is a sialoprotein implicated in different immunity and metabolic pathways. Capable of activating dendritic cells and inducing Th1-Th17-mediated tissue damage, OPN plays a significant role in the development/progression of several autoimmune diseases; interestingly, it was also shown that OPN participates in the acute pancreatic islets response to experimentally induced diabetes in non-obese diabetic (NOD) mice. Furthermore, OPN promotes adipose tissue dysfunction, systemic inflammation and insulin resistance. Our aims of this study were to evaluate circulating OPN levels in adult patients with type 1 diabetes mellitus (T1DM) compared to non-diabetic control participants and to unravel clinical and biochemical correlates of OPN concentration.

DESIGN

Case-control study.

METHODS

We enrolled 54 consecutive T1DM patients referred to our diabetes outpatient clinic at Sapienza University of Rome and 52 healthy sex and age-comparable controls. The study population underwent clinical evaluation, blood sampling for biochemistry and complete screening for diabetes complications. Serum OPN levels were measured by MILLIPLEX Multiplex Assays Luminex.

RESULTS

T1DM patients had significantly higher serum OPN levels than controls (17.2±12.9 vs 10.5±11.6 mg/ml, P=0.009). OPN levels correlated with T1DM, higher blood pressure, BMI, creatinine, γ-GT, ALP and lower HDL; the association between high OPN levels and T1DM was independent from all confounders. No correlation was shown between OPN and HbA1c, C-peptide, insulin requirement, co-medications and diabetes duration.

CONCLUSIONS

This study demonstrates for the first time in a case-control study that adults with T1DM have increased serum OPN levels, and that higher OPN concentrations are associated with an unfavorable metabolic profile in these patients.

The interplay among iron metabolism, endothelium and inflammatory cascade in dysmetabolic disorders

PURPOSE

Metabolic syndrome (MetS) is considered as a proinflammatory and prothrombotic state with atherogenic risk factors including dyslipidemia, obesity and glucose intolerance. Oxidative stress is a unifying basis of several disorders including diabetes mellitus (DM) and MetS. We therefore designed this cross-sectional study to investigate the potential interaction among iron metabolism, inflammation and endothelial plexus in MetS and DM patients.

METHODS

A total of 62 patients [median age 54 (23-76) years; male/female 16/46] and 18 healthy controls [median age 38 (30-64) years; male/female 6/12] were included in the study. Patient population was classified as MetS (n = 30) and DM (n = 32).

RESULTS

Leukocyte count (p = 0.002) and osteopontin (OPN) levels (p = 0.008) were significantly higher, while C-reactive protein (CRP) (p = 0.056) and IL-6 (p = 0.059) represented a relative increase in the patient group. Leptin, endothelin 1 (ET1), hepcidin, nitric oxide synthase (NOS), erythrocyte sedimentation rate (ESR), iron, transferrin saturation (TS) and ferritin levels were not significantly different between the patient and control groups. Endothelin 1 was found to be higher in the DM group compared to MetS group (p = 0.15, p = 0.049). Leukocyte count, leptin, hepcidin, OPN, NOS, IL-6, ESR, CRP, iron, TS and ferritin levels were not different between DM and MetS groups. A positive correlation was demonstrated between leptin and OPN (p = 0.001, r = 0.360), ferritin and hepcidin (p < 0.01, r = 0.633), IL-6 and CRP (p = 0.023, r = 0.319), leptin and NOS (p = 0.005, r = 0.309) and OPN and NOS (p < 0.001, r = 0.803). There was a negative correlation between hepcidin and NOS (p = 0.009, r = -0.289). When the study cohort was divided into two particular groups based on median ferritin and hepcidin levels, hepcidin (p = 0.002), ALT (p = 0.001) and LDL (p = 0.049) levels were higher in the high-ferritin group. Nitric oxide synthase levels (p = 0.033) were lower, whereas ferritin levels (p = 0.004) were higher in the high-hepcidin group.

CONCLUSION

Mechanisms involved in the vicious circle of MetS including inflammation, endothelial vasculature and iron metabolism remain to be elucidated. The role of iron metabolism in this complex interaction should be confirmed with further studies.

Influence of physicochemical properties of silver nanoparticles on mast cell activation and degranulation

Silver nanoparticles (AgNPs) are increasingly being incorporated into products for their antimicrobial properties. This has resulted in increased human exposures and the possibility of adverse health effects. Mast cells orchestrate allergic immune responses through degranulation and release of pre-formed mediators. Little data exists on understanding interactions of AgNPs with mast cells and the properties that influence activation and degranulation. Using bone marrow-derived mast cells and AgNPs of varying physicochemical properties we tested the hypothesis that AgNP physicochemical properties influence mast cell degranulation and osteopontin production. AgNPs evaluated included spherical 20 nm and 110 nm suspended in either polyvinylpyrrolidone (PVP) or citrate, Ag plates suspended in PVP of diameters between 40–60 nm or 100–130 nm, and Ag nanowires suspended in PVP with thicknesses <100 nm and length up to 2 μm. Mast cell responses were found to be dependent on the physicochemical properties of the AgNP. Further, we determined a role for scavenger receptor B1 in AgNP-induced mast cell responses. Mast cell degranulation was not dependent on AgNP dissolution but was prevented by tyrosine kinase inhibitor pretreatment. This study suggests that exposure to AgNPs may elicit adverse mast cell responses that could contribute to the initiation or exacerbation of allergic disease.