Osteopontin

Comparison of supplementation of n-3 fatty acids from fish and flax oil on cytokine gene expression and growth of milk-fed Holstein calves

The ability to reduce incidence of disease in calves and improve early vaccination strategies is of particular interest for dairy producers. The n-3 fatty acids have been reported to reduce inflammatory diseases in humans but limited research has been done in calves. The objective of this study was to compare supplementation of n-3 fatty acids from fish and flax oil on gene expression of whole blood cells and growth of milk-fed Holstein calves. Forty-eight Holstein bull calves from a commercial dairy were randomly assigned to 1 of 3 diets beginning at 4d old: (1) control milk replacer (MR) with all pork fat, (2) MR with 2% flax oil, and (3) MR with 2% fish oil. All MR were 17% fat, 27% crude protein on a dry matter (DM) basis, with all protein from whey sources. Calves were each fed 654g DM of MR daily for the first 25d and then 327g/d for d26, 27, and 28. On d28, calves were challenged with a Pasteurella vaccine and the temperature response to the vaccine was recorded. Milk and feed intake and fecal scores were recorded daily, and body weight and hip width were recorded weekly. Blood was collected from all calves on d25. One tube of collected blood was incubated with endotoxin (lipopolysaccharide; LPS) for 2h and frozen with a second tube of control blood. Quantitative real-time PCR was used to assess the effects of LPS stimulation on cytokine gene expression. During the 28 d, calves supplemented with flax oil had a greater growth rate and feed efficiency than calves fed fish oil (0.52±0.02 vs. 0.48±0.02g of gain:g of feed). Fish oil tended to decrease LPS stimulation of tumor necrosis factor-α expression. Flax oil, but not fish oil, decreased the expression of IL-4 and tended to decrease expression of osteopontin and IL-8. Flax oil tended to reduce the increase in rectal temperature in response to a Pasteurella vaccine. In conclusion, our data support the idea that supplementation with n-3 fatty acids affects cytokine gene expression.

Osteopontin and galectin-3 predict the risk of ventricular tachycardia and fibrillation in heart failure patients with implantable defibrillators

BACKGROUND

Myocardial extracellular matrix remodelling provides electrical heterogeneity entailing ventricular tachycardia/fibrillation (VT/VF) in heart failure (HF) patients. Osteopontin (OPN) and Galectin-3 (Gal-3) are fibrosis markers and may reflect the extension of the arrhythmogenic substrate. We assessed whether plasma OPN and Gal-3 predict the risk of sustained VT/VF in a cohort of HF patients with implantable cardioverter-defibrillator (ICD).

METHODS

A total of 75 HF patients underwent pre-ICD implantation clinical evaluation and assessment of plasma OPN and Gal-3. The primary endpoint was the time to the occurrence of the first sustained VT/VF. Hazard ratios (HR) were derived from Cox proportional-hazards analysis.

RESULTS

Patients with coronary artery disease (CAD) had higher plasma OPN (79.8 ± 44.0 ng/mL vs. 66.0 ± 31.8 ng/mL; P = 0.04). Both Gal-3 (r = -0.38; P = 0.01) and OPN (r = -0.27; p = 0.01) were negatively related to estimated glomerular filtration rate. After 29 ± 17 months, 20 patients (27%) reached the primary endpoint. Patients with VT/VF had higher plasma OPN and Gal-3 (97.4 ± 51.7 ng/mL vs. 65.9 ± 31.3 ng/mL; P = 0.002 and 19.7 ± 8.5 ng/mL vs. 16.2 ± 6.2 ng/mL; P = 0.05). In univariate analysis, OPN (log-OPN, HR: 32.4; 95%CI: 3.9-264.7; P = 0.001) and Gal-3 (HR: 1.05; 95%CI: 1.00-1.11; P = 0.04) predicted sustained VT/VF. In multivariable analysis, both OPN (HR: 41.4; 95%CI: 3.8-441.9; P = 0.002) and Gal-3 (HR: 1.06; 95%CI: 1.00-1.12; P = 0.03) retained their prognostic power after correction for age, sex, history of MI, EF, NYHA class, eGFR, use of ACE-I, and amiodarone.

CONCLUSIONS

Plasma OPN and Gal-3 predict sustained VT/VF in HF patients at high risk for SCD. Larger prospective studies should outline the role of these biomarkers in predicting SCD on top of conventional risk stratification.

Biomarkers of vascular calcification and mortality in patients with ESRD

BACKGROUND

Vascular calcification is common among patients undergoing dialysis and is associated with mortality. Factors such as osteoprotegerin (OPG), osteopontin (OPN), bone morphogenic protein-7 (BMP-7), and fetuin-A are involved in vascular calcification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

OPG, OPN, BMP-7, and fetuin-A were measured in blood samples from 602 incident dialysis patients recruited from United States dialysis centers between 1995 and 1998 as part of the Choices for Healthy Outcomes In Caring for ESRD Study. Their association with all-cause and cardiovascular mortality were assessed using Cox proportional hazards models adjusted for demographic characteristics, comorbidity, serum phosphate, and calcium. An interaction with diabetes was tested because of its known association with vascular calcification. Predictive accuracy of selected biomarkers was explored by C-statistics in nested models with training and validation subcohorts.

RESULTS

Higher OPG and lower fetuin-A levels were associated with higher mortality over up to 13 years of follow-up (median, 3.4 years). The adjusted hazard ratios (HR) for highest versus lowest tertile were 1.49 (95% confidence interval [95% CI], 1.08 to 2.06) for OPG and 0.69 (95% CI, 0.52 to 0.92) for fetuin-A. In stratified models, the highest tertile of OPG was associated with higher mortality among patients without diabetes (HR, 2.42; 95% CI, 1.35 to 4.34), but not patients with diabetes (HR, 1.26; 95% CI, 0.82 to 1.93; P for interaction=0.001). In terms of cardiovascular mortality, higher fetuin-A was associated with lower risk (HR, 0.85 per 0.1 g/L: 95% CI, 0.75 to 0.96). In patients without diabetes, higher OPG was associated with greater risk (HR for highest versus lowest tertile, 2.91; 95% CI, 1.06 to 7.99), but not in patients with diabetes or overall. OPN and BMP-7 were not independently associated with outcomes overall. The addition of OPG and fetuin-A did not significantly improve predictive accuracy of mortality.

CONCLUSIONS

OPG and fetuin-A may be risk factors for all-cause and cardiovascular mortality in patients undergoing dialysis, but do not improve risk prediction.

Bioprosthetic heart valves of the future

Glutaraldehyde-fixed bioprosthetic heart valves (GBHVs), derived from pigs or cows, undergo structural valve deterioration (SVD) over time, with calcification and eventual failure. It is generally accepted that SVD is due to chemical processes between glutaraldehyde and free calcium ions in the blood. Valve companies have made significant progress in decreasing SVD from calcification through various valve chemical treatments. However, there are still groups of patients (e.g., children and young adults) that have accelerated SVD of GBHV. Unfortunately, these patients are not ideal patients for valve replacement with mechanical heart valve prostheses as they are at high long-term risk from complications of the mandatory anticoagulation that is required. Thus, there is no "ideal" heart valve replacement for children and young adults. GBHVs represent a form of xenotransplantation, and there is increasing evidence that SVD seen in these valves is at least in part associated with xenograft rejection. We review the evidence that suggests that xenograft rejection of GBHVs is occurring, and that calcification of the valve may be related to this rejection. Furthermore, we review recent research into the transplantation of live porcine organs in non-human primates that may be applicable to GBHVs and consider the potential use of genetically modified pigs as sources of bioprosthetic heart valves.

Increased plasma osteopontin in frequent exacerbator and acute exacerbation of COPD

INTRODUCTION

Osteopontin (OPN) is a phosphorylated glycoprotein expressed by diverse tissues including bone, brain, kidney, liver and lung. Limited data exist regarding OPN in chronic obstructive pulmonary disease (COPD) and the exacerbation of this condition.

OBJECTIVES

The aim of this study was to evaluate plasma OPN levels and investigate the clinical usefulness of plasma OPN measurement in patients with COPD.

METHODS

Plasma OPN levels were measured and compared in patients with COPD exacerbation (n = 64), patients with stable COPD (n = 68) and healthy controls (n = 30). In patients with COPD exacerbation, plasma OPN levels were measured repeatedly in convalescence. Patients with stable COPD were categorized into frequent and infrequent exacerbators according to their frequency of exacerbation, and plasma OPN levels were compared between these two groups. Plasma OPN levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Patients with COPD exacerbation had increased plasma OPN levels compared with those with stable COPD and healthy controls (32.6 ± 29.6, 17.6 ± 11.1, 8.4 ± 6.1 ng/mL, respectively; P < 0.001). In patients with COPD exacerbation, plasma OPN levels were significantly decreased in convalescence (44.8 ± 43.5 vs 24.6 ± 13.6 ng/mL; P = 0.034). Frequent exacerbators had higher plasma OPN levels compared with infrequent exacerbators (22.5 ± 12.0 vs 15.0 ± 9.8 ng/mL; P = 0.008).

CONCLUSIONS

Plasma OPN levels were increased in patients with COPD exacerbation and frequent exacerbators, which suggests a possible role for OPN as a biomarker of COPD exacerbation.

Age-associated (cardio)metabolic diseases and cross-talk between adipose tissue and skeleton: endocrine aspects

Aged individuals continue to increase in number, and it is important to understand the pathophysiological mechanisms of age-related changes in order to develop interventions that could contribute to “successful aging”. Metabolic and hormonal factors, age-related changes in body composition, and a decline in physical activity are all involved in the tendency to lose muscle mass, to gain fat mass, and, also, to experience bone loss. Obesity, sarcopenia, and osteoporosis are important widespread health problems that lead to high prevalence of both mortality and morbidity. Indeed, during the last decades, obesity and osteoporosis have become a major health threat around the world. Aging increases the risk of developing obesity, sarcopenia, osteoporosis, and, also, cardiovascular diseases. A reduction of both bone and muscle mass with a corresponding increase of fat mass and inflammation and hormonal imbalance in the elderly lead to and may synergistically increase cardiovascular diseases. This review will focus on the relationship among these different medical situations, trying to clarify the cellular and molecular mechanisms.

Pharmacogenomics in the development and characterization of atheroprotective drugs

Atherosclerosis is the main cause of cardiovascular disease (CVD) and can lead to stroke, myocardial infarction, and death. The clinically available atheroprotective drugs aim mainly at reducing the levels of circulating low-density lipoprotein (LDL), increasing high-density lipoprotein (HDL), and attenuating inflammation. However, the cardiovascular risk remains high, along with morbidity, mortality, and incidence of adverse drug events. Pharmacogenomics is increasingly contributing towards the characterization of existing atheroprotective drugs, the evaluation of novel ones, and the identification of promising, unexplored therapeutic targets, at the global molecular pathway level. This chapter presents highlights of pharmacogenomics investigations and discoveries that have contributed towards the elucidation of pharmacological atheroprotection, while opening the way to new therapeutic approaches.

Serum osteopontin, but not OPN gene polymorphism, is associated with LVH in essential hypertensive patients

This study aims to investigate the role of osteopontin (OPN) genetic polymorphisms in the occurrence of left ventricular hypertrophy (LVH) in Chinese patients with essential hypertension (EH). A total of 1,092 patients diagnosed with EH were recruited. Three single nucleotide polymorphisms (SNP) on the promoter region of the OPN gene, including -66T/G, -156G/GG, and -443C/T were genotyped. The serum thrombin-cleaved OPN levels were studied. Patients were divided into LVH+ (n = 443) and the LVH- (n = 649) groups. We found that none of the studied SNPs in the OPN gene was associated with the risk and severity of LVH. The SNPs in the OPN gene did not correlate with the serum OPN levels. However, the serum thrombin-cleaved OPN levels were found to be an independent risk factor for LVH in the EH patients. Multivariate logistic regression analysis showed that serum thrombin-cleaved OPN levels were independently associated with the development of LVH (adjusted OR = 2.47, 95 % CI 1.56-4.01, adjusted P < 0.001). In vitro studies showed that the thrombin-cleaved OPN treatment increased the protein content per cell, the cardiomyocyte surface size, and the expression level of atrial natriuretic peptide protein in a dose-dependent manner. The thrombin-cleaved OPN serum level, but not OPN gene polymorphism, is associated with the development of LVH in EH patients.

KEY MESSAGES

Serum OPN is related to LVH incidence in essential hypertension subjects. OPN stimulates cardiomyocyte hypertrophy in vitro. OPN SNPs are not related to LVH incidence.

Genetics of the type I interferon pathway in systemic lupus erythematosus

Genetic studies of systemic lupus erythematosus (SLE) have been successful, identifying numerous risk factors for human disease. While the list is not yet complete, it is clear that important immune system pathways are represented, one of which being type I interferon (IFN). Circulating type I IFN levels are high in SLE patients and this IFN pathway activation is heritable in families with SLE. We summarize our current understanding of the genetics of the type I IFN pathway in SLE, with an emphasis on studies that demonstrate an impact of the SLE-risk alleles upon type I IFN pathway activation in SLE patients. These studies illustrate that variations in type I IFN pathway genes represent a common genetic feature of SLE. By understanding the genetic regulation of type I IFN, we may be able to intervene in a more personalized fashion, based upon the molecular dysregulation present in a given individual.

Danger signals in the initiation of the inflammatory response after myocardial infarction

During myocardial infarction, sterile inflammation occurs. The danger model is a solid theoretic framework that explains this inflammation as danger associated molecular patterns activate the immune system. The innate immune system can sense danger signals through different pathogen recognition receptors (PRR) such as toll-like receptors, nod-like receptors and receptors for advanced glycation endproducts. Activation of a PRR results in the production of cytokines and the recruitment of leukocytes to the site of injury. Due to tissue damage and necrosis of cardiac cells, danger signals such as extracellular matrix (ECM) breakdown products, mitochondrial DNA, heat shock proteins and high mobility box 1 are released. Matricellular proteins are non-structural proteins expressed in the ECM and are upregulated upon injury. Some members of the matricellular protein family (like tenascin-C, osteopontin, CCN1 and the galectins) have been implicated in the inflammatory and reparative responses following myocardial infarction and may function as danger signals. In a clinical setting, danger signals can function as prognostic and/or diagnostic biomarkers and for drug targeting. In this review we will provide an overview of the established knowledge on the role of danger signals in myocardial infarction and we will discuss areas of interest for future research.

10-years experience with the Athero-Express study

From cross-sectional studies we have learned that composition of atherosclerotic plaques differs, and that thrombosis on top of an inflammatory lipid rich plaque is a frequently observed pathological substrate of a cerebral or coronary event. Atherosclerosis develops over decades which hampers human studies on the natural history of the diseases. Therefore, the predictive value of atherosclerotic plaque composition for development of an adverse cardiovascular event is not clear. The elucidation of markers for atherosclerotic disease progression is essential to identify patients at high risk for vascular events, to refine treatment allocation and to serve as surrogate endpoints in pharmaceutical studies. The Athero-Express study is a large scale vascular biobank that collects vascular specimens including a clinical follow-up. This study design allows the prospective study of the local atherosclerotic plaque in relation to future local and systemic vascular outcome. The readout of the study can be assessed in terms of histology as well as RNA or protein level. This paper aims to give an overview of the results of the Athero-Express biobank since its initiation in 2002. We will also discuss the clinical implications and future directions in biobanking research.

The effects of MyD88 deficiency on disease phenotype in dysferlin-deficient A/J mice: role of endogenous TLR ligands

An absence of dysferlin leads to activation of innate immune receptors such as Toll-like receptors (TLRs) and skeletal muscle inflammation. Myeloid differentiation primary response gene 88 (MyD88) is a key mediator of TLR-dependent innate immune signalling. We hypothesized that endogenous TLR ligands released from the leaking dysferlin-deficient muscle fibres engage TLRs on muscle and immune cells and contribute to disease progression. To test this hypothesis, we generated and characterized dysferlin and MyD88 double-deficient mice. Double-deficient mice exhibited improved body weight, grip strength, and maximum muscle contractile force at 6-8 months of age when compared to MyD88-sufficient, dysferlin-deficient A/J mice. Double-deficient mice also showed a decrease in total fibre number, which contributed to the observed increase in the number of central nuclei/fibres. These results indicate that there was less regeneration in the double-deficient mice. We next tested the hypothesis that endogenous ligands, such as single-stranded ribonucleic acids (ssRNAs), released from damaged muscle cells bind to TLR-7/8 and perpetuate the disease progression. We found that injection of ssRNA into the skeletal muscle of pre-symptomatic mice (2 months old) resulted in a significant increase in degenerative fibres, inflammation, and regenerating fibres in A/J mice. In contrast, characteristic histological features were significantly decreased in double-deficient mice. These data point to a clear role for the TLR pathway in the pathogenesis of dysferlin deficiency and suggest that TLR-7/8 antagonists may have therapeutic value in this disease.

Role of miR-181 family in regulating vascular inflammation and immunity

The microRNA family, miR-181, plays diverse roles in regulating key aspects of cellular growth, development, and activation. Accumulating evidence supports a central role for the miR-181 family in vascular inflammation by controlling critical signaling pathways, such as downstream NF-κB signaling, and targets relevant to endothelial cell activation and immune cell homeostasis. This review examines the current knowledge of the miR-181 family's role in key cell types that critically control cardiovascular inflammation under pathological and physiological stimuli.

Molecular biology of atherosclerosis

At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.

Bone metabolism regulators and arterial stiffness in postmenopausal women

BACKGROUND

Osteoprotegerin (OPG), osteopontin (OPN) and matrix Gla protein (MGP) are markers of bone metabolism but they are also involved in vascular calcification. However, their precise role is not completely understood. Arterial stiffness is considered an independent predictor of cardiovascular events and it may be one of the causes of the increased cardiovascular risk associated with postmenopausal status. Medial and intimal calcification may increase arterial stiffness. The aim of our study was to assess the relationship of OPG, OPN and MGP with aortic pulse wave velocity (aPWV) as a marker of arterial stiffness in postmenopausal women.

MATERIALS AND METHODS

Circulating OPG, OPN and serum total MGP were measured in 144 postmenopausal women using the enzyme-linked immunosorbent assay method. Aortic PWV was determined by an oscillometric method.

RESULTS

Osteoprotegerin correlated with age (p<0.001, r=0.27), aPWV (p<0.001, r=0.32) and hypersensitive C reactive protein (hsCRP) (p<0.001, r=0.37), OPN correlated directly with hsCRP (p<0.001, r=0.39) and inversely with high density lipoprotein cholesterol (p=0.02, r=-0.02). No significant association was found between total MGP and clinical, biochemical and vascular parameters. The correlation between OPG and aPWV persisted even after the adjustment for various potential confounders (p=0.02, r=0.19). In multiple regression analysis in the whole study population the most important predictors of aPWV were OPG (β=0.230, p=0.006), hsCRP (β=0.212, p=0.01) and systolic blood pressure (β=0.163, p=0.04). After exclusion of patients treated with statins the independent predictors were hsCRP (β=0.275, p=0.005) and OPG (β=0.199, p=0.04).

CONCLUSION

Circulating OPG, but not OPN and total MGP, is associated with aPWV and may be a marker of the increased arterial stiffness and cardiovascular risk in postmenopausal women.

High serum osteopontin levels are associated with low bone mineral density in postmenopausal women

Osteopontin (OPN) is an acidic, noncollagenous matrix protein produced by the bone and kidneys. It is reportedly involved in bone resorption and formation. We examined the association between serum OPN levels and bone mineral density in postmenopausal women. Premenopausal women (n=32) and postmenopausal women (n=409) participated in the study. We measured serum osteopontin levels and their relationships with bone mineral density and previous total fragility fractures. The postmenopausal women had higher mean serum OPN levels compared to the premenopausal women (43.6±25.9 vs 26.3±18.6 ng/mL; P<0.001). In the postmenopausal women, high serum OPN levels were negatively correlated with mean lumbar bone mineral density (BMD) (r=-0.113, P=0.023). In a stepwise multiple linear regression model, serum OPN levels were associated with BMD of the spine, femoral neck, and total hip after adjustment for age, body mass index, smoking, and physical activity in postmenopausal women. However, serum OPN levels did not differ between postmenopausal women with and without fractures. Postmenopausal women exhibit higher serum OPN levels than premenopausal women and higher serum OPN levels were associated with low BMD in postmenopausal women.

Identification of an adipogenic niche for adipose tissue remodeling and restoration

The regulatory events guiding progenitor activation and differentiation in adult white adipose tissue are largely unknown. We report that induction of brown adipogenesis by β3-adrenergic receptor (ADRB3) activation involves the death of white adipocytes and their removal by M2-polarized macrophages. Recruited macrophages express high levels of osteopontin (OPN), which attracts a subpopulation of PDGFRα+ progenitors expressing CD44, a receptor for OPN. Preadipocyte proliferation is highly targeted to sites of adipocyte clearance and occurs almost exclusively in the PDGFRα+ CD44+ subpopulation. Knockout of OPN prevents formation of crown-like structures by ADRB3 activation and the recruitment, proliferation, and differentiation of preadipocytes. The recruitment and differentiation of PDGFRα+ progenitors are also observed following physical injury, during matrix-induced neogenesis, and in response to high-fat feeding. Each of these conditions recruits macrophages having a unique polarization signature, which may explain the timing of progenitor activation and the fate of these cells in vivo.

Serum level of osteopontin as an inflammatory marker does not indicate disease activity or responsiveness to therapeutic treatments in patients with rheumatoid arthritis

Osteopontin (OPN) is known to be significantly involved in the pathogenesis of rheumatoid arthritis (RA). This study aimed to evaluate if the serum concentration of OPN in patients with RA before and after therapeutic treatments was correlated to disease activity and response to therapy. Blood samples from 40 patients with RA were collected at baseline and six months after starting treatment with disease-modifying antirheumatic drugs (DMARDs) and/or tumor necrosis factor (TNF)-α blockers. Serum levels of OPN were measured by ELISA. At baseline, the serum OPN level in RA patients was significantly higher than that of the healthy group. The OPN level at baseline in RA patients with severe disease activity as evaluated by DAS28 was slightly higher than that of those with moderate disease activity. The serum OPN level in RA patients was not significantly correlated with the DAS28 level. The serum OPN level in both responders and non-responders after therapy was significantly decreased regardless of responsiveness to therapy. Also, the OPN level at baseline did not affect the responsiveness to therapeutic treatments. In conclusion, serum OPN level was not correlated with disease activity or responsiveness of RA patients to therapeutic treatments.

Serum osteoprotegerin and osteopontin levels are associated with arterial stiffness and the presence and severity of coronary artery disease

BACKGROUND

Osteopontin (OPN) and osteoprotegerin (OPG) have recently emerged as key factors in both vascular remodeling and development of atherosclerosis. Arterial stiffness has an independent predictive value for cardiovascular events. We evaluate the relationship between OPG, OPN serum levels and vascular function in coronary artery disease (CAD) patients.

METHODS

The study population was consisted of 409 subjects (280 with CAD and 129 without CAD). Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness. OPG and OPN levels were measured, as markers of vascular remodeling and calcification, by ELISA. Gensini score was used to evaluate the extent of CAD.

RESULTS

CAD patients, compared to those without CAD, had higher OPG (3.91 ± 1.87 pmol/l vs. 2.88 ± 1.32 pmol/l, p<0.001) and logOPN levels (1.81 ± 0.18 ng/ml vs. 1.71 ± 0.24 ng/ml, p<0.001) and impaired PWV (8.94 ± 2.21 m/s vs. 8.28 ± 1.91 m/s, p=0.006). Furthermore, PWV was associated with serum OPG levels (r=0.19, p<0.001) and with serum logOPN levels (r=0.10, p=0.049). Multivariate linear regression analysis revealed that increased OPG (p=0.013) and logOPN (p=0.006) levels are associated with 3-vessel CAD and Gensini score (p=0.04 for OPG and p=0.09 for OPN), independently of other known cardiovascular risk factors.

CONCLUSION

The present study revealed that serum OPG and OPN levels are positively associated with arterial stiffness, and with the extent of CAD. These preliminary results suggest that OPG and OPN levels are significantly correlated with vascular function contributing to the pathogenesis of atherosclerosis in CAD. Further studies are needed to explore the mechanisms of action of OPG and OPN in CAD.

Dissection of the human multipotent adult progenitor cell secretome by proteomic analysis

Multipotent adult progenitor cells (MAPCs) are adult adherent stromal stem cells currently being assessed in acute graft versus host disease clinical trials with demonstrated immunomodulatory capabilities and the potential to ameliorate detrimental autoimmune and inflammation-related processes. Our previous studies documented that MAPCs secrete factors that play a role in regulating T-cell activity. Here we expand our studies using a proteomics approach to characterize and quantify MAPC secretome components secreted over 72 hours in vitro under steady-state conditions and in the presence of the inflammatory triggers interferon-γ and lipopolysaccharide, or a tolerogenic CD74 ligand, RTL1000. MAPCs differentially responded to each of the tested stimuli, secreting molecules that regulate the biological activity of the extracellular matrix (ECM), including proteins that make up the ECM itself, proteins that regulate its construction/deconstruction, and proteins that serve to attach and detach growth factors from ECM components for redistribution upon appropriate stimulation. MAPCs secreted a wide array of proteases, some detectable in their zymogen forms. MAPCs also secreted protease inhibitors that would regulate protease activity. MAPCs secreted chemokines and cytokines that could provide molecular guidance cues to various cell types, including neutrophils, macrophages, and T cells. In addition, MAPCs secreted factors involved in maintenance of a homeostatic environment, regulating such diverse programs as innate immunity, angiogenesis/angiostasis, targeted delivery of growth factors, and the matrix-metalloprotease cascade.

Diagnostic and prognostic value of osteopontin in patients with acute congestive heart failure

AIMS

To evaluate the diagnostic and prognostic value of osteopontin in patients with acute dyspnoea and/or peripheral oedema suspected of having acute congestive heart failure (aCHF).

METHODS AND RESULTS

A total of 401 patients presenting with acute dyspnoea and/or peripheral oedema to the emergency department were prospectively enrolled and followed up for up to 5 years. Blood samples for biomarker measurements were collected on admission to the emergency department. Osteopontin combined with NT-proBNP vs. NT-proBNP alone for diagnosis of aCHF was tested. Additionally, osteopontin vs. NT-proBNP for prognostic outcomes (i.e. all-cause mortality, aCHF-related rehospitalization, and both in combination) was tested. The diagnostic and prognostic capacity of osteopontin was tested by C-statistics, reclassification indices, and multivariable Cox prediction models. Osteopontin plus NT-proBNP improved the diagnostic capacity for aCHF diagnosis [accuracy 76%, 95% confidence interval (CI) 72-80%; specificity 74%, 95% CI 69-79%, net reclassification improvement (NRI) +0.10] compared with NT-proBNP alone in the emergency department (P = 0.0001). Osteopontin independently predicted all-cause mortality and aCHF-related rehospitalization after 1 and 5 years. Compared with NT-proBNP, osteopontin was of superior prognostic value, specifically in aCHF patients and for the prognostic outcome of aCHF-related rehospitalization.

CONCLUSION

Osteopontin improves aCHF diagnosis when combined with NT-proBNP. Osteopontin identifies aCHF patients with high 1- and 5-year mortality and rehospitalization risk, and adds prognostic value to NT-proBNP. Trial registration NCT00143793.

More than a simple storage organ: adipose tissue as a source of adipokines involved in cardiovascular disease

Overweight and obesity in many countries have developed into a serious health problem by themselves and by their impact on other pathologies such as insulin resistance, type 2 diabetes, hypertension, heart disease and cancer. The modulation of these diseases by adipose tissue-derived biomolecules, so-called adipokines, could be the key to differentiate between metabolically healthy and unhealthy obesity. This review will discuss the pathophysiological role of selected adipokines, primarily focusing on cardiovascular diseases. Furthermore, we will highlight possible therapeutic approaches, which target these biomolecules.

Osteopontin in bone mineral density of very old Brazilians

Recent evidence suggests that changes in plasma levels of osteopontin (OPN) may be a promising marker for early diagnosis of bone disorders. We hypothesized that a frequent OPN gene polymorphism may be useful for identifying very old individuals with alterations in plasma OPN levels and consequently at risk of abnormal bone density scores. Men and women (80 years or older) living in the Brazilian Federal District underwent assessments with dual energy X-ray absorptiometry for bone mineral density (BMD) of the femoral neck, femoral head and lumbosacral (L1 to S5) regions. Clinical inspection was performed to assess other physical traits and to exclude co-morbidities (cardiovascular, autoimmunity, infections or neoplastic diseases). Serum concentrations of OPN were determined with an enzyme-linked immunosorbent assay, whereas the A7385G polymorphism (rs1126772) was determined by direct sequencing of a polymerase chain reaction product. Among the two hundred and ten subjects enrolled, no differential scores for bone mineral density could be observed across genotypes, but a greater content of circulating OPN was found among carriers of the A allele (P ≤ 0.05) even after adjustments. Serum OPN levels were negatively correlated with femoral neck density (P = 0.050 for BMD; P = 0.032 for T scores) but not with scores of the other regions investigated. Analyses with the sample dichotomized to age and body mass revealed that this inverse relationship was noticeable only among those aged within the highest and weighing within the lowest intervals. Our findings indicate elevated circulating osteopontin levels in patients with decreased bone mineral density, consistent with a modest contribution of an OPN allelic variation to its expression. Assessing the clinical relevance of our findings demands forthcoming studies.

Derivation of human peripheral blood derived endothelial progenitor cells and the role of osteopontin surface modification and eNOS transfection

Endothelial coverage of blood-contacting biomaterial surfaces has been difficult to achieve. A readily available autologous source of endothelium combined with an appropriate attachment substrate would improve the chances of developing functional surfaces. Here we describe methods to derive high quantities of human endothelial progenitor cells (EPCs) from peripheral blood monocytes (PBMCs) obtained by leukapheresis. These cells are morphologically and phenotypically similar to human umbilical vein endothelial cells (HUVECs); however, their expression of the key vascular factor - endothelial nitric oxide synthase (eNOS) - is markedly lower than that observed in HUVECs. We demonstrate that eNOS levels can be restored with plasmid-based transfection. To promote EPC adherence we examined substrate enhancement with a matricellular protein associated with vascular repair, osteopontin (OPN). We observed dose- and time-dependent responses of OPN in EPC adhesion, spreading, and haptotactic migration of EPCs in Boyden chamber assays. In addition, the combination of the OPN coating and enhanced eNOS expression in EPCs maximally enhanced cell adhesion (39.6 ± 1.7 and 49.4 ± 2.4 cells/field for 0 and 1 nM OPN) and spreading (84.7 ± 3.5% and 92.1 ± 3.9% for 0 nM and 1 nM OPN). These data highlight the direct effects of OPN on peripheral blood derived EPCs, suggesting that OPN works by mediating progenitor cell adhesion during vascular injury. The combination of autologous EPCs and OPN coatings could be a promising method of developing functional endothelialized surfaces.

Lack of Cyp1b1 promotes the proliferative and migratory phenotype of perivascular supporting cells

Perivascular supporting cells, including pericytes and smooth muscle cells (PC/SMC), have an integral role during angiogenesis and control vascular remodeling, maturation, and stabilization of neoteric vessels. We recently showed that a Cyp1B1 deficiency in mice results in the attenuation of angiogenesis in vivo and the pro-angiogenic activity of endothelial cells in vitro. However, the contribution of PC/SMC, and more specifically the cell autonomous effects of Cyp1B1 in these processes, needs further investigation. Here we demonstrate that PC constitutively expressed Cyp1B1, and that a deficiency in Cyp1B1 was associated with enhanced proliferation, and decreased apoptosis. Mechanistically, the lack of Cyp1B1 was associated with increased oxidative stress and sustained NF-κB activation, which was reversed by the antioxidant N-acetylcysteine. These changes were also concomitant with alterations in PC migration, adhesion, and expression of various extracellular matrix proteins, including thrombospondin-2. Cyp1B1-deficient PC also expressed decreased levels of vascular endothelial growth factor. Together, our results suggest an important role for Cyp1B1 expression in the regulation of PC proliferation, migration, and survival through modulation of the intracellular oxidative state and NF-κB expression and/or activity. Thus, a lack of Cyp1B1 in PC may have a significant role in vascular dysfunction and integrity, contributing to the attenuation of angiogenesis.

Peripheral signalling involved in energy homeostasis control

The alarming prevalence of obesity has led to a better understanding of the molecular mechanisms controlling energy homeostasis. Regulation of energy intake and expenditure is more complex than previously thought, being influenced by signals from many peripheral tissues. In this sense, a wide variety of peripheral signals derived from different organs contributes to the regulation of body weight and energy expenditure. Besides the well-known role of insulin and adipokines, such as leptin and adiponectin, in the regulation of energy homeostasis, signals from other tissues not previously thought to play a role in body weight regulation have emerged in recent years. The role of fibroblast growth factor 21 (FGF21), insulin-like growth factor 1 (IGF-I), and sex hormone-binding globulin (SHBG) produced by the liver in the regulation of body weight and insulin sensitivity has been recently described. Moreover, molecules expressed by skeletal muscle such as myostatin have also been involved in adipose tissue regulation. Better known is the involvement of ghrelin, cholecystokinin, glucagon-like peptide 1 (GLP-1) and PYY(3-36), produced by the gut, in energy homeostasis. Even the kidney, through the production of renin, appears to regulate body weight, with mice lacking this hormone exhibiting resistance to diet-induced obesity. In addition, the skeleton has recently emerged as an endocrine organ, with effects on body weight control and glucose homeostasis through the actions of bone-derived factors such as osteocalcin and osteopontin. The comprehension of these signals will help in a better understanding of the aetiopathology of obesity, contributing to the potential development of new therapeutic targets aimed at tackling excess body fat accumulation.

Chronic hypoxia reprograms human immature dendritic cells by inducing a proinflammatory phenotype and TREM-1 expression

DCs are powerful antigen-presenting cells central in the orchestration of innate and acquired immunity. DC development, migration, and activities are intrinsically linked to the microenvironment. DCs migrate through pathologic tissues before reaching their final destination in the lymph nodes. Hypoxia, a condition of low partial oxygen pressure, is a common feature of many pathologic situations, capable of modifying DC phenotype and functional behavior. We studied human monocyte-derived immature DCs generated under chronic hypoxic conditions (H-iDCs). We demonstrate by gene expression profiling the upregulation of a cluster of genes coding for antigen-presentation, immunoregulatory, and pattern recognition receptors, suggesting a stimulatory role for hypoxia on iDC immunoregulatory functions. In particular, we show that H-iDCs express triggering receptor expressed on myeloid cells(TREM-1), a member of the Ig superfamily of immunoreceptors and an amplifier of inflammation. This effect is reversible because H-iDC reoxygenation results in TREM-1 down-modulation. TREM-1 engagement promotes upregulation of T-cell costimulatory molecules and homing chemokine receptors, typical of mature DCs, and increases the production of proinflammatory, Th1/Th17-priming cytokines/chemokines, resulting in increased T-cell responses. These results suggest that TREM-1 induction by the hypoxic microenvironment represents a mechanism of regulation of Th1-cell trafficking and activation by iDCs differentiated at pathologic sites.

Proteolytic processing of osteopontin by PHEX and accumulation of osteopontin fragments in Hyp mouse bone, the murine model of X-linked hypophosphatemia

X-linked hypophosphatemia (XLH/HYP)-with renal phosphate wasting, hypophosphatemia, osteomalacia, and tooth abscesses-is caused by mutations in the zinc-metallopeptidase PHEX gene (phosphate-regulating gene with homologies to endopeptidase on the X chromosome). PHEX is highly expressed by mineralized tissue cells. Inactivating mutations in PHEX lead to distal renal effects (implying accumulation of a secreted, circulating phosphaturic factor) and accumulation in bone and teeth of mineralization-inhibiting, acidic serine- and aspartate-rich motif (ASARM)-containing peptides, which are proteolytically derived from the mineral-binding matrix proteins of the SIBLING family (small, integrin-binding ligand N-linked glycoproteins). Although the latter observation suggests a local, direct matrix effect for PHEX, its physiologically relevant substrate protein(s) have not been identified. Here, we investigated two SIBLING proteins containing the ASARM motif-osteopontin (OPN) and bone sialoprotein (BSP)-as potential substrates for PHEX. Using cleavage assays, gel electrophoresis, and mass spectrometry, we report that OPN is a full-length protein substrate for PHEX. Degradation of OPN was essentially complete, including hydrolysis of the ASARM motif, resulting in only very small residual fragments. Western blotting of Hyp (the murine homolog of human XLH) mouse bone extracts having no PHEX activity clearly showed accumulation of an ∼35 kDa OPN fragment that was not present in wild-type mouse bone. Immunohistochemistry and immunogold labeling (electron microscopy) for OPN in Hyp bone likewise showed an accumulation of OPN and/or its fragments compared with normal wild-type bone. Incubation of Hyp mouse bone extracts with PHEX resulted in the complete degradation of these fragments. In conclusion, these results identify full-length OPN and its fragments as novel, physiologically relevant substrates for PHEX, suggesting that accumulation of mineralization-inhibiting OPN fragments may contribute to the mineralization defect seen in the osteomalacic bone characteristic of XLH/HYP.

A study of the link between bone turnover markers and bone mineral density with inflammation and body mass in postmenopausal women with active rheumatoid arthritis

In this study, the levels of bone turnover markers (BTMs) and bone mineral density (BMD) were studied in relation to body mass and several inflammatory markers, in postmenopausal patients with rheumatoid arthritis (RA). Fifty-nine postmenopausal women with active RA (lean, overweight, obese) were studied. The femoral BMD and serum levels of BTMs: osteocalcin (OC) and collagen type I cross-linked C-telopeptide fragments (CTX), and osteopontin (OPN), resistin, high sensitivity C-reactive protein, interleukin-6, tumor necrosis factor (TNF)-α in these patients were measured. It has been noticed that obese women had significantly higher total femoral BMD and total T-score compared to the lean subjects (p ≤ 0.01). The significant associations of BMD measures and CTX levels with body mass parameters (p ≤ 0.01 and p < 0.05, respectively) were found. Values of neck BMD adjusted for BMI were inversely associated with concentrations of TNF-α (p < 0.05). Osteocalcin levels inversely correlated with resistin (p ≤ 0.01) and CTX levels positively correlated with OPN (p ≤ 0.01). There were found no associations between BTMs and BMD with other inflammatory indices. Inverse correlations between OPN levels and body mass (p < 0.05), waist circumference (p < 0.05), and duration of postmenopausal period (p ≤ 0.01) were observed. Findings of the present study suggest that body mass and inflammatory markers, most of all OPN, resistin and TNF-α, play an important role in bone metabolism in postmenopausal women with active RA.

Osteopontin deficiency dampens the pro-atherogenic effect of uraemia

AIMS

Uraemia is a strong risk factor for cardiovascular disease. Osteopontin (OPN) is highly expressed in aortas of uraemic apolipoprotein E knockout (E KO) mice. OPN affects key atherogenic processes, i.e. inflammation and phenotypic modulation of smooth muscle cells (SMCs). We explored the role of OPN on vascular pathology in uraemic mice.

METHODS AND RESULTS

Uraemia was induced by 5/6 nephrectomy in E KO and in OPN and E double KO mice (E/OPN KO). In E KO mice, uraemia increased the relative surface plaque area in the aortic arch (from 28 ± 2% [n = 15], to 37 ± 3% [n = 20] of the aortic arch area, P < 0.05). A positive correlation was observed between plasma OPN and aortic atherosclerosis in uraemic E KO mice (r(2) = 0.48, P = 0.001). In contrast, aortic atherosclerosis was not increased by uraemia in E/OPN KO mice. OPN deficiency in haematopoietic cells (including macrophages) did not affect development of uraemic atherosclerosis, even though OPN-deficient foam cells had decreased inflammatory capacity. Gene expression analyses indicated that uraemia de-differentiates SMCs in the arterial wall. This effect was dampened in whole-body OPN-deficient mice.

CONCLUSION

The data suggest that OPN promotes development of uraemic atherosclerosis possibly by changing the phenotype of vascular smooth muscle cells.

N-terminal rather than full-length osteopontin or its C-terminal fragment is associated with carotid-plaque inflammation in hypertensive patients

BACKGROUND

Hypertensive patients develop carotid atherosclerotic plaques with enhanced inflammation. Full-length osteopontin (OPN-FL), a multifunctional protein whose levels are elevated in association with atherosclerosis, is cleaved by thrombin and matrix metalloproteinases to form a C-terminal and a putatively biologically active N-terminal fragment (OPN-C, OPN-N, respectively). We conducted a study to examine whether plaque inflammation in hypertensive patients corresponds to the expression of OPN or of its cleaved forms or both.

METHODS

We collected 42 carotid plaques from 41 consecutive hypertensive patients during carotid endarterectomy. Plaque tissue was used to measure matrix metalloproteinase-12 (MMP-12) and OPN proteins, and for the classification of plaques as showing low- or high-degree inflammation through histological and immunohistochemical evaluation.

RESULTS

Fifteen highly inflamed plaques and 27 plaques with characteristics of low-grade inflammation were collected. Moderate to heavy staining for OPN characterized 87% of the plaques with high-degree inflammation but only 44% of those with low-degree inflammation, corresponding to the percentages of plaques that were heavily stained for the macrophage marker CD68 (93% versus 26%, respectively, P < 0.01). Western blot analysis showed that the abundance of OPN-FL and OPN-C was comparable in the two groups. However, the abundance of OPN-N was significantly greater in the highly inflamed plaques (median, 3.8 (range, 0.8-7.3) vs. median, 0.9 (range, 0.2-1.5); P = 0.017, respectively). The abundance of MMP-12 was significantly greater in the high- than in the low-degree plaque inflammation group (4.8 (range 1.9-8.8) vs. 1.1 (range 0.3-1.4), respectively; P = 0.03).

CONCLUSIONS

The N-terminal fragment of osteopontin, rather than OPN-FL or OPN-C, is associated with carotid plaque inflammation in hypertensive patients. Future studies should assess whether targeting OPN cleavage could present a new approach to preventing high-risk carotid plaques.

Expression of osteopontin in patients with thyroid dysfunction

Thyroid dysfunctions are common endocrine problems. They are often misdiagnosed, misunderstood, and frequently overlooked. These disorders affect almost every aspect of health. Most of them remain undetected because the clinical assessment alone lacks both sensitivity and specificity. As it is not sufficient enough we require the biochemical tests to confirm the diagnosis. As a consequence there is still great interest in new biomarkers that complement existing diagnostic tools. Osteopontin, a glycoprotein that can be detected in plasma, was found to be upregulated in several patients with hyperthyroidism and downregulated in hypothyroid patients so it may represent a new biomarker. 100 patients with thyroid dysfunctions (50 hyperthyroid, 50 hypothyroid) and 100 normal subjects were included in the study. Osteopontin and other clinical parameters for diagnosis of thyroid disorders were measured. Osteopontin is positively correlated with T3 and T4 (r = 0.62 and r = 0.75 respectively) while it is negatively correlated with thyroid stimulating hormone (r = -0.52) showing a significant correlation (p-value <0.001). Our findings suggest that osteopontin might be useful as a novel prognostic biomarker in patients with impaired thyroid function.

Bariatric surgery, bone loss, obesity and possible mechanisms

Bariatric surgery remains the most effective treatment for severely obese patients. However, the potential long-term effects of bariatric surgical procedures on health, including bone health, are only partially understood. The goal of this review was to present data on the impact of bariatric surgery on bone metabolism and to analyse possible reasons for the loss of bone mass that frequently occurs after bariatric surgery. Such factors include nutritional deficiencies, rapid weight loss per se, effects of fat-derived adipokines and gut-derived appetite-regulatory hormones. However, the relative roles of these factors in skeletal regulation and the mechanisms by which they work are not yet fully defined. Our review was focussed on the complex relationship between body weight, fat mass and bone mass, as well as peripheral and central mediators potentially involved in the dual regulation of both energy and bone homeostasis. We also review the data on the inverse relationship between central obesity, bone marrow fat and osteoporosis. As the number of bariatric operations increases, it is imperative to recognize mechanisms responsible for bariatric surgery-induced bone loss, with careful monitoring of bone health including long-term fracture incidence in patients undergoing these procedures.

Regulatory circuits controlling vascular cell calcification

Vascular calcification is a common feature of chronic kidney disease, cardiovascular disease, and aging. Such abnormal calcium deposition occurs in medial and/or intimal layers of blood vessels as well as in cardiac valves. Once considered a passive and inconsequential finding, the presence of calcium deposits in the vasculature is widely accepted as a predictor of increased morbidity and mortality. Recognition of the importance of vascular calcification in health is driving research into mechanisms that govern its development, progression, and regression. Diverse, but highly interconnected factors, have been implicated, including disturbances in lipid metabolism, oxidative stress, inflammatory cytokines, and mineral and hormonal balances, which can lead to formation of osteoblast-like cells in the artery wall. A tight balance of procalcific and anticalcific regulators dictates the extent of disease. In this review, we focus on the main regulatory circuits modulating vascular cell calcification.

Biomolecular mechanism of urinary stone formation involving osteopontin

Urinary stones consist of two phases-an inorganic (mineral) phase and an organic (matrix) phase. Studies on the organic components of kidney stones have been undertaken later than those on the inorganic components. After osteopontin was identified as one of the matrix components, the biomolecular mechanism of urinary stone formation became clearer. It also triggered the development of new preventive treatments. Osteopontin expression is sporadically observed in normal distal tubular cells and is markedly increased in stone-forming kidneys. Calcium oxalate crystals adhering to renal tubular cells are incorporated into cells by the involvement of osteopontin. Stimulation of crystal-cell adhesion impairs the opening of mitochondrial permeability transition pores (mPTP) in tubular cells and produces oxidative stress, apoptosis, and osteopontin expression. Macrophages phagocytose and digest a small amount of crystals, but many crystals aggregate into a mass containing osteopontin and epithelial cell debris and are excreted into the renal tubular lumen, becoming nuclei of urinary stones. This biomolecular mechanism is similar to atherosclerotic calcification. Based on these findings, new preventive treatments have been developed. Dietary control such as low-cholesterol intake and the ingestion of antioxidative foods and vegetables have successfully reduced the 5-year recurrence rate. Osteopontin antibodies and cyclosporine A, which blocks the opening of mPTP, have markedly inhibited the expression of osteopontin and urinary stone formation in animal models.

Soluble levels of osteopontin in patients with Behcet's disease: association with disease activity and vascular involvement

AIM

Osteopontin (OPN) is a multifunctional molecule highly expressed in chronic inflammatory and autoimmune diseases. We aimed to assess the plasma OPN levels in Behcet's disease (BD) patients and identify potential associations between these levels with disease activity, severity and clinical manifestations with special emphasis on vascular affection.

METHODS

We studied 55 BD patients and 31 age- and gender-matched healthy controls. Demographic, clinical and serological data were prospectively assessed. Activity and severity of BD were assessed using clinical scores and laboratory parameters. Plasma OPN levels were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Plasma OPN levels were significantly higher in patients with BD compared to healthy controls (p < 0.000). The means for plasma OPN levels in active and inactive BD patients were significantly higher than that for the normal controls (with p < 0.000 and p = 0.002 respectively). The mean OPN levels significantly associated with the BD clinical severity score from mild to severe (p = 0.011). BD patients with vascular involvement had significant elevation of plasma OPN levels than those without (P = 0.03). OPN levels positively correlated with severity score, IL6, hsCRP, ESR, leucocytes count and neutrophil count.

CONCLUSION

Plasma OPN levels were higher in BD patients than in healthy controls and were found to be associated with disease activity, severity and vascular involvement. To confirm our results we propose that larger scale, multicentre studies with longer evaluation periods are needed.

Macrophages modulate cardiac function in lipotoxic cardiomyopathy

Diabetes is associated with myocardial lipid accumulation and an increased risk of heart failure. Although cardiac myocyte lipid overload is thought to contribute to the pathogenesis of cardiomyopathy in the setting of diabetes, the mechanism(s) through which this occurs is not well understood. Increasingly, inflammation has been recognized as a key pathogenic feature of lipid excess and diabetes. In this study, we sought to investigate the role of inflammatory activation in the pathogenesis of lipotoxic cardiomyopathy using the α-myosin heavy chain promoter-driven long-chain acylCoA synthetase 1 (MHC-ACS) transgenic mouse model. We found that several inflammatory cytokines were upregulated in the myocardium of MHC-ACS mice before the onset of cardiac dysfunction, and this was accompanied by macrophage infiltration. Depletion of macrophages with liposomal clodrolip reduced the cardiac inflammatory response and improved cardiac function. Thus, in this model of lipotoxic cardiac injury, early induction of inflammation and macrophage recruitment contribute to adverse cardiac remodeling. These findings have implications for our understanding of heart failure in the setting of obesity and diabetes.

In vitro and clinical studies examining the expression of osteopontin in cigarette smoke-exposed endothelial cells and cigarette smokers

Background

Cigarette smoking is a leading cause of mortality and morbidity and is associated with cardiovascular disease via contributory processes such as endothelial dysfunction, inflammation and thrombosis. Cigarette smoke both contains and stimulates the production of cellular oxidants and it may also promote vascular inflammation. Osteopontin is a non-collagenous matrix protein first identified in bone and there is increasing evidence for its role in inflammation and cardiovascular disease via its action as a soluble cytokine.

Methods

In this study we have examined the mechanisms underlying the expression of osteopontin in human vascular endothelial cells in vitro following exposure to cigarette smoke particulate matter (PM), using PCR, electrochemiluminescence, immunostaining and Western blotting. We further determined if serum osteopontin levels changed in humans who quit smoking.

Results

Non-cytotoxic concentrations of PM increased osteopontin levels in cultured human endothelial cells and this effect was reduced in the presence of ascorbate, suggesting a role for oxidants in the response to PM. However, oxidant production played no role in the PM-evoked induction MMP-3, an enzyme which cleaves osteopontin. In smokers who quit smoking for 5 days, serum osteopontin levels were significantly lowered compared to those measured prior to smoking cessation.

Conclusions

In vitro cigarette smoke extract exposure induced osteopontin expression in human endothelial cells in an oxidative stress-dependent manner, which may involve MMP-3 cleavage. In humans, serum osteopontin was decreased with short-term smoking cessation. Endothelial-derived osteopontin may contribute to inflammation in smokers, and may also contribute to atherosclerosis and cardiovascular disease-related processes.

Arterial calcification and bone physiology: role of the bone-vascular axis

Bone never forms without vascular interactions. This simple statement of fact does not adequately reflect the physiological and pharmacological implications of the relationship. The vasculature is the conduit for nutrient exchange between bone and the rest of the body. The vasculature provides the sustentacular niche for development of osteoblast progenitors and is the conduit for egress of bone marrow cell products arising, in turn, from the osteoblast-dependent haematopoietic niche. Importantly, the second most calcified structure in humans after the skeleton is the vasculature. Once considered a passive process of dead and dying cells, vascular calcification has emerged as an actively regulated form of tissue biomineralization. Skeletal morphogens and osteochondrogenic transcription factors are expressed by cells within the vessel wall, which regulates the deposition of vascular calcium. Osteotropic hormones, including parathyroid hormone, regulate both vascular and skeletal mineralization. Cellular, endocrine and metabolic signals that flow bidirectionally between the vasculature and bone are necessary for both bone health and vascular health. Dysmetabolic states including diabetes mellitus, uraemia and hyperlipidaemia perturb the bone-vascular axis, giving rise to devastating vascular and skeletal disease. A detailed understanding of bone-vascular interactions is necessary to address the unmet clinical needs of an increasingly aged and dysmetabolic population.

Prognostic utility of pre-operative circulating osteopontin, carbonic anhydrase IX and CRP in renal cell carcinoma

Background:

Objectively measured circulating biomarkers of prognosis complementing existing clinicopathological models are needed in renal cell carcinoma (RCC).

Methods:

Blood samples collected from 216 RCC patients in Leeds before nephrectomy (median follow-up 7 years) were analysed for C-reactive protein (CRP), osteopontin (OPN) and carbonic anhydrase IX (CA9) and prognostic significance determined.

Results:

CA9, OPN and CRP were univariately prognostic for overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS) with CRP and CA9 being independently prognostic for OS/CSS and OS, respectively. Including CA9, OPN and CRP with other conventional prognostic factors gave a superior predictive capacity when compared with a previously published pre-operative clinical nomogram (Karakiewicz et al, 2009). Osteopontin outperformed this nomogram and the post-operative SSIGN score for OS but not for CSS, being significantly predictive for non-cancer deaths. Osteopontin, CRP and CA9 outperformed stage (c-index 76% compared with 70% for stage) and OPN or CA9 identified several subsets of poor prognosis patients including in T1 patients, who may benefit from adjuvant therapy and increased surveillance.

Conclusion:

Circulating CA9, OPN and CRP add value to existing clinicopathological prognostic factors/models and support further studies to investigate their potential use in improving the clinical management of RCC.

Osteoporosis--a risk factor for cardiovascular disease?

Osteoporosis is a serious health problem worldwide that is associated with an increased risk of fractures and mortality. Vascular calcification is a well-defined independent risk factor for cardiovascular disease (CVD) and mortality. Major advances in our understanding of the pathophysiology of osteoporosis and vascular calcification indicate that these two processes share common pathogenetic mechanisms. Multiple factors including proteins (such as bone morphogenetic proteins, receptor activator of nuclear factor κB ligand, osteoprotegerin, matrix Gla protein and cathepsins), parathyroid hormone, phosphate, oxidized lipids and vitamins D and K are implicated in both bone and vascular metabolism, illustrating the interaction of these two, seemingly unrelated, conditions. Many clinical studies have now confirmed the correlation between osteoporosis and vascular calcification as well as the increased risk of CVD in patients with osteoporosis. Here, we explore the proposed mechanistic similarities between osteoporosis and vascular calcification and present an overview of the clinical data that support the interaction between these conditions.

Humanin prevents intra-renal microvascular remodeling and inflammation in hypercholesterolemic ApoE deficient mice

AIMS

Humanin (HN) is an endogenous mitochondrial-derived cytoprotective peptide that has shown protective effects against atherosclerosis and is expressed in human vessels. However, its effects on the progression of kidney disease are unknown. We hypothesized that HN would protect the kidney in the early phase of atherogenesis.

MAIN METHODS

Forty-eight mice were studied in four groups (n=12 each). Twenty-four ApoE deficient mice were fed a 16-week high-cholesterol diet supplemented with saline or HN (4mg/kg/day, intraperitoneal). C57BL/6 mice were fed a normal diet supplemented with saline or HN. Microvascular architecture was assessed with micro-CT and vascular wall remodeling by alpha-SMA staining. The effects of HN on angiogenesis, inflammation, apoptosis and fibrosis were evaluated in the kidney tissue by Western blotting and histology.

KEY FINDINGS

Cortical microvascular spatial density and media/lumen area ratio were significantly increased in high-cholesterol diet fed ApoE deficient mice, but restored by HN. HN up-regulated the renal expressions of anti-angiogenic proteins angiostatin and TSP-1, and inhibited angiopoietin-1. HN attenuated inflammation by down-regulating MCP-1, TNF-alpha and osteopontin. HN also tended to restore pSTAT3 and attenuated Bax expression, suggesting blunted apoptosis. Kidney collagen IV expression was alleviated by HN treatment.

SIGNIFICANCE

HN attenuates renal microvascular remodeling, inflammation and apoptosis in the early stage of kidney disease in hypercholesterolemic ApoE(-/-) mice. HN may serve as a novel therapeutic target to mitigate kidney damage in early atherosclerosis.

Vascular endothelial growth factor-induced osteopontin expression mediates vascular inflammation and neointima formation via Flt-1 in adventitial fibroblasts

OBJECTIVE

Adventitia acts as an active participant in vascular inflammation but the precise mechanism underlying adventitia-mediated vascular inflammation is not fully understood. In this study, we sought to determine whether vascular endothelial growth factor (VEGF) regulates osteopontin (OPN) expression through Flt-1 in adventitial fibroblasts (AFs) to mediate vascular inflammation and neointima formation.

METHODS AND RESULTS

In primary cultured AFs, VEGF increased intracellular and secreted OPN expression in a time- and dose-dependent manner, which was effectively suppressed by a specific anti-Flt-1 hexapeptide. Interestingly, VEGF treatment of AFs enhanced the capability of AF-conditioned medium to stimulate macrophages chemotaxis, and this effect was attenuated after blockade of OPN from AF-conditioned medium. Furthermore, perivascular delivery of anti-Flt-1 peptide preferentially concentrated in the adventitia resulted in a decrease of neointima formation after balloon injury in carotid arteries. The inhibition of neointima formation was preceded by significant reduction of VEGF and OPN expression with concurrent macrophage infiltration into adventitia after injury. Activation of extracellular signal-regulated kinase 1/2 pathway was involved in OPN upregulation and macrophage chemotaxis.

CONCLUSIONS

These results demonstrate that VEGF/Flt-1 signaling plays a significant role in vascular inflammation and neointima formation by regulating OPN expression in AFs and provide insight into Flt-1 as a potential therapeutic target for vascular diseases.

Elastic fiber-mediated enthesis in the human middle ear

Adaptation to constant vibration (acoustic oscillation) is likely to confer a specific morphology at the bone-tendon and bone-ligament interfaces at the ear ossicles, which therefore represent an exciting target of enthesis research. We histologically examined (i) the bone attachments of the tensor tympani and stapedius muscles and (ii) the annular ligament of the incudostapedial joint obtained from seven elderly donated cadavers. Notably, both aldehyde-fuchsin and elastic-Masson staining demonstrated that the major fibrous component of the entheses was not collagen fibers but mature elastic fibers. The positive controls for elastic fiber staining were the arterial wall elastic laminae included in the temporal bone materials. The elastic fibers were inserted deeply into the type II collagen-poor fibrocartilage covering the ear ossicles. The muscle tendons were composed of an outer thin layer of collagen fibers and an inner thick core of elastic fibers near the malleus or stapes. In the unique elastic fiber-mediated entheses, hyaluronan, versican and fibronectin were expressed strongly along the elastic fibers. The hyaluronan seemed to act as a friction-reducing lubricant for the elastic fibers. Aggrecan was labeled strongly in a disk- or plica-like fibrous mass on the inner side of the elastic fiber-rich ligament, possibly due to compression stress from the ligament. Tenascin-c was not evident in the entheses. The elastic fiber-mediated entheses appeared resistant to tissue destruction in an environment exposed to constant vibration. The morphology was unlikely to be the result of age-related degeneration.