Osteopontin

Effects of oral paricalcitol therapy on arterial stiffness and osteopontin in hypertensive patients with chronic kidney disease and secondary hyperparathyroidism

BACKGROUND

Arterial stiffness is linked to the progression of atherosclerosis, while activation of vitamin D receptor exerts favorable cardiovascular effects in patients with renal insufficiency. In this study, we investigated the effects of oral treatment with paricalcitol, a potent vitamin D receptor activator, on arterial stiffness and osteopontin, a marker of atherosclerosis, in hypertensive patients with chronic kidney disease (CKD) and secondary hyperparathyroidism.

METHODS

We followed up 29 treated hypertensive patients (mean age: 74.1 years, 19 men, office blood pressure = 132/85 mmHg) with CKD stages 3-5 (mean glomerular filtration rate [GFR] = 19.4 ml/min/1.73 m²) who were on therapy with oral paricalcitol for 1 year. The control group consisted of 10 age-, sex-, and GFR-matched hypertensive patients with secondary hyperparathyroidism.

RESULTS

After 1 year of treatment with paricalcitol compared to baseline, there was no statistical difference in levels of GFR, office blood pressure, and osteopontin (p = NS for all), while carotid-femoral PWV was reduced from 11.8 ± 2.6 m/s to 11.2 ± 2.4 m/s (p < 0.05). The control group exhibited no significant changes in carotid-femoral PWV (p = NS).

CONCLUSIONS

Treatment with oral paricalcitol in hypertensive subjects suffering from CKD stages 3-5 and secondary hyperparathyroidism is accompanied by amelioration of arterial stiffness as reflected by the reduction of carotid-femoral PWV.

A novel role for osteopontin in macrophage-mediated amyloid-β clearance in Alzheimer's models

Osteopontin (OPN), a matricellular immunomodulatory cytokine highly expressed by myelomonocytic cells, is known to regulate immune cell migration, communication, and response to brain injury. Enhanced cerebral recruitment of monocytes achieved through glatiramer acetate (GA) immunization or peripheral blood enrichment with bone marrow (BM)-derived CD115⁺ monocytes (Mo^BM) curbs amyloid β-protein (Aβ) neuropathology and preserves cognitive function in murine models of Alzheimer's disease (ADtg mice). To elucidate the beneficial mechanisms of these immunomodulatory approaches in AD, we focused on the potential role of OPN in macrophage-mediated Aβ clearance. Here, we found extensive OPN upregulation along with reduction of vascular and parenchymal Aβ burden in cortices and hippocampi of GA-immunized ADtg mice. Treatment combining GA with blood-grafted Mo^BM further increased OPN levels surrounding residual Aβ plaques. In brains from AD patients and ADtg mice, OPN was also elevated and predominantly expressed by infiltrating GFP⁺- or Iba1⁺-CD45^high monocyte-derived macrophages engulfing Aβ plaques. Following GA immunization, we detected a significant increase in a subpopulation of inflammatory blood monocytes (CD115⁺CD11b⁺Ly6C^high) expressing OPN, and subsequently, an elevated population of OPN-expressing CD11b⁺Ly6C⁺CD45^high monocyte/macrophages in the brains of these ADtg mice. Correlogram analyses indicate a strong linear correlation between cerebral OPN levels and macrophage infiltration, as well as a tight inverse relation between OPN and Aβ-plaque burden. In vitro studies corroborate in vivo findings by showing that GA directly upregulates OPN expression in BM-derived macrophages (MФ^BM). Further, OPN promotes a phenotypic shift that is highly phagocytic (increased uptake of Aβ fibrils and surface scavenger receptors) and anti-inflammatory (altered cell morphology, reduced iNOS, and elevated IL-10 and Aβ-degrading enzyme MMP-9). Inhibition of OPN expression in MФ^BM, either by siRNA, knockout (KO^OPN), or minocycline, impairs uptake of Aβ fibrils and hinders GA's neuroprotective effects on macrophage immunological profile. Addition of human recombinant OPN reverses the impaired Aβ phagocytosis in KO^OPN-MФ^BM. This study demonstrates that OPN has an essential role in modulating macrophage immunological profile and their ability to resist pathogenic forms of Aβ.

Association between decreased osteopontin and acute mountain sickness upon rapid ascent to 3500 m among young Chinese men

BACKGROUND

Hypoxia causes oxidative stress and a decrease in osteopontin (OPN) in rats; however, little is known about the change in OPN in lowlander humans during hypobaric hypoxia. We explore the role of the predicted decrease in plasma OPN levels in humans upon high-altitude exposure and its relationship with acute mountain sickness (AMS), as well as superoxide dismutase (SOD) and malondialdehyde (MDA).

METHODS

Before and during acute altitude exposure, 261 men's plasma OPN, SOD, MDA, heart rate and pulse oximeter saturation (SpO2) were measured. AMS as assessed using the Lake Louise score (LLS) was defined as headache with a total LLS ≥3. Subjects were divided into AMS-0 (non-AMS subjects), mild AMS (headache with total LLS = 3 or 4) and severe AMS groups (headache with total LLS ≥5).

RESULTS

At 600 m, no difference in plasma OPN, SOD and MDA was observed between groups. At 3500 m, plasma OPN in severe AMS group was significantly decreased as compared with 600 m. Plasma SOD showed a tendency to decrease during altitude exposure. The opposite trend was observed for plasma MDA. Correlation analysis showed that total LLS was significantly correlated with OPN (ρ = -0.247, P < 0.001) and SOD (ρ = -0.224, P < 0.001). OPN showed significant correlation with SOD (r = 0.235, P < 0.001). Multivariate logistic regression analysis showed that higher plasma OPN was a protective factor for AMS [adjusted odds ratio (OR) 0.924, 95% confidence interval (CI) 0.884-0.966, P < 0.01].

CONCLUSION

Our results suggest that decreased plasma OPN is correlated with AMS, and oxidative stress may be implicated in this phenomenon. Decreased plasma SOD is also correlated with AMS.

Osteopontin, Cardiovascular Risk Factors and Carotid Intima-Media Thickness in Chronic Kidney Disease

The pleiotropic cytokine osteopontin (OPN) is found to be involved in the pathogenesis of both kidney and cardiovascular disease (CVD). We evaluated the relationship between OPN, other cardiovascular risk factors and carotid intima-media thickness (CIMT) in chronic kidney disease (CKD) (predialysis) patients. This is a 2-year cross-sectional prospective study involving 75 patients with CKD from stage 1 to stage 5 attending the nephrology outpatient department and 25 healthy controls. Routine biochemical parameters were analyzed on clinical chemistry Autoanalyzer Beckman Coulter DXC 600 Synchron, USA. OPN was estimated by ELISA method. Carotid intima-media wall thickness was estimated by Doppler of carotid vessels. Serum OPN and other nontraditional cardiovascular risk factors such as CIMT, lipoprotein (a) Lp(a), fibrinogen, and homocysteine were significantly increased in patients of CKD compared to controls. OPN, Lp(a), fibrinogen, CIMT, parathyroid hormone, and homocysteine progressively increased from early stages of CKD and increased further with progression of the disease, but nitric oxide (NO) level progressively decreased with progression of CKD. OPN showed a positive correlation with CIMT, Lp(a), fibrinogen, and homocysteine and negative correlation with estimated glomerular filtration rate and NO. There was a close direct association between circulating levels of OPN and the presence of atherosclerotic plaques in carotid arteries of patients with CKD. Osteopontin and nontraditional CVD risk factors are altered in early stages of CKD and might predict adverse outcomes in these patients.

Serum osteopontin: a biomarker of disease activity and predictor of relapsing course in patients with giant cell arteritis. Potential clinical usefulness in tocilizumab-treated patients

Background

Osteopontin (OPN) is a glycoprotein involved in Th1 and Th17 differentiation, tissue inflammation and remodelling. We explored the role of serum OPN (sOPN) as a biomarker in patients with giant cell arteritis (GCA).

Methods

sOPN was measured by immunoassay in 76 treatment-naïve patients with GCA and 25 age-matched and sex-matched controls. In 36 patients, a second measurement was performed after 1 year of glucocorticoid treatment. Baseline clinical and laboratory findings, as well as relapses and glucocorticoid requirements during follow-up, were prospectively recorded. sOPN and C reactive protein (CRP) were measured in 32 additional patients in remission treated with glucocorticoids or tocilizumab (interleukin 6 (IL-6) receptor antagonist). In cultured temporal arteries exposed and unexposed to tocilizumab, OPN mRNA expression and protein production were measured by reverse transcription polymerase chain reaction (RT-PCR) and immunoassay, respectively.

Results

sOPN concentration (ng/mL; mean±SD) was significantly elevated in patients with active disease (116.75±65.61) compared with controls (41.10±22.65; p<0.001). A significant decline in sOPN was observed in paired samples as patients entered disease remission (active disease 102.45±57.72, remission 46.47±23.49; p<0.001). sOPN correlated with serum IL-6 (r=0.55; p<0.001). Baseline sOPN concentrations were significantly higher in relapsing versus non-relapsing patients (relapsers 129.08±74.24, non-relapsers 90.63±41.02; p=0.03). OPN mRNA expression and protein production in cultured arteries were not significantly modified by tocilizumab. In tocilizumab-treated patients, CRP became undetectable, whereas sOPN was similar in patients in tocilizumab-maintained (51.91±36.25) or glucocorticoid-maintained remission (50.65±23.59; p=0.49).

Conclusions

sOPN is a marker of disease activity and a predictor of relapse in GCA. Since OPN is not exclusively IL-6-dependent, sOPN might be a suitable disease activity biomarker in tocilizumab-treated patients.

Role of Perivascular Adipose Tissue in Health and Disease

Perivascular adipose tissue (PVAT) is cushion of fat tissue surrounding blood vessels, which is phenotypically different from other adipose tissue depots. PVAT is composed of adipocytes and stromal vascular fraction, constituted by different populations of immune cells, endothelial cells, and adipose-derived stromal cells. It expresses and releases an important number of vasoactive factors with paracrine effects on vascular structure and function. In healthy individuals, these factors elicit a net anticontractile and anti-inflammatory paracrine effect aimed at meeting hemodynamic and metabolic demands of specific organs and regions of the body. Pathophysiological situations, such as obesity, diabetes or hypertension, induce changes in its amount and in the expression pattern of vasoactive factors leading to a PVAT dysfunction in which the beneficial paracrine influence of PVAT is shifted to a pro-oxidant, proinflammatory, contractile, and trophic environment leading to functional and structural cardiovascular alterations and cardiovascular disease. Many different PVATs surrounding a variety of blood vessels have been described and exhibit regional differences. Both protective and deleterious influence of PVAT differs regionally depending on the specific vascular bed contributing to variations in the susceptibility of arteries and veins to vascular disease. PVAT therefore, might represent a novel target for pharmacological intervention in cardiovascular disease. © 2018 American Physiological Society. Compr Physiol 8:23-59, 2018.

Bisphosphonates, atherosclerosis and vascular calcification: update and systematic review of clinical studies

Background

Epidemiologic and clinical data have suggested the existence of a biologic linkage between the bone system and the vascular system. Bisphosphonates (BPs) are effective inhibitors of bone resorption and are currently considered the drugs of choice for the prevention and treatment of osteoporosis and related fractures. Data from several publications have suggested that BPs may also be effective in reducing the atherosclerotic process and vascular calcification, but the results of these studies are contrasting. This review aimed to allow a better understanding of the relationships between BPs and atherosclerosis in humans.

Materials and methods

Electronic databases of Pubmed-Medline, Cochrane Library and SCOPUS from inception to June 30, 2016 were searched. The full texts of the articles potentially eligible were carefully assessed and reviewed. Finally, 20 studies were found to be eligible and were included in the systematic review. All included studies were published between 2000 and 2014.

Results

In several studies, etidronate limited the progression of aortic and coronary calcification in hemodialysis patients, whereas the nitrogen-containing-BPs given orally did not significantly reduce vascular calcifications in patients with chronic kidney disease, kidney trasplant or in those with osteoporosis. Nitrogen-containing-BPs present favorable effects both on vessel wall thickness and on arterial elasticity due to both a reduction in serum lipids and the interaction of BPs with the bone tissue, with the consequent release of bone turnover markers and cytokines into the bloodstream.

Conclusion

To sum up, the BPs seem to have the potential of influencing atherosclerosis and calcium homeostasis at the level of vascular walls with several possible mechanisms which may differ according to the type, potency, dosage and administration route of BPs. Additional studies are needed to specifically address the mechanism by which BP use could influence cardiovascular morbidity and mortality.

Hypoxia and Redox Signaling on Extracellular Matrix Remodeling: From Mechanisms to Pathological Implications

SIGNIFICANCE

The extracellular matrix (ECM) is an essential modulator of cell behavior that influences tissue organization. It has a strong relevance in homeostasis and translational implications for human disease. In addition to ECM structural proteins, matricellular proteins are important regulators of the ECM that are involved in a myriad of different pathologies. Recent Advances: Biochemical studies, animal models, and study of human diseases have contributed to the knowledge of molecular mechanisms involved in remodeling of the ECM, both in homeostasis and disease. Some of them might help in the development of new therapeutic strategies. This review aims to review what is known about some of the most studied matricellular proteins and their regulation by hypoxia and redox signaling, as well as the pathological implications of such regulation.

CRITICAL ISSUES

Matricellular proteins have complex regulatory functions and are modulated by hypoxia and redox signaling through diverse mechanisms, in some cases with controversial effects that can be cell or tissue specific and context dependent. Therefore, a better understanding of these regulatory processes would be of great benefit and will open new avenues of considerable therapeutic potential.

FUTURE DIRECTIONS

Characterizing the specific molecular mechanisms that modulate matricellular proteins in pathological processes that involve hypoxia and redox signaling warrants additional consideration to harness the potential therapeutic value of these regulatory proteins. Antioxid. Redox Signal. 27, 802-822.

Identification of serum proteins and multivariate models for diagnosis and therapeutic monitoring of lung cancer

Lung cancer is one of the most prevalent cancers and has very poor treatment outcome. Biomarkers useful for screening and assessing early therapeutic response may significantly improve the therapeutic outcome but are still lacking. In this study, serum samples from 218 non-small cell lung cancer (NSCLC) patients, 34 small cell lung cancer (SCLC) patients and 171 matched healthy controls from China were analyzed for 11 proteins using the Luminex multiplex assay. Eight of the 11 proteins (OPN, SAA, CRP, CYFRA21.1, CEA, NSE, AGP and HGF) are significantly elevated in NSCLC and SCLC (p = 10⁻⁵−10⁻⁵⁹). At the individual protein level, OPN has the best diagnostic value for NSCLC (AUC = 0.92), two acute phase proteins (SAA and CRP) have AUC near 0.83, while CEA and CYFRA21.1 also possess good AUC (0.81 and 0.77, respectively). More importantly, several three-protein combinations that contain OPN and CEA plus one of four proteins (CRP, SAA, CYFRA21.1 or NSE) have excellent diagnostic potential for NSCLC (AUC = 0.96). Four proteins (CYFRA21.1, CRP, SAA and NSE) are severely reduced and three proteins (OPN, MIF and NSE) are moderately decreased after platinum-based chemotherapy. Therapeutic response index (TRI) computed with 3–5 proteins suggests that approximately 25% of the NSCLC patients respond well to the therapy and TRI is significantly correlated with pre-treatment protein levels. Our data suggest that therapeutic response in NSCLC patients can be effectively measured but personalized biomarkers may be needed to monitor different subsets of patients.

Plasma level of Osteopontin does not respond to total replacement Surgery in patients with severe Primary knee/Hip Osteoarthritis

OBJECTIVE

To test the response of Osteopontin levels in patients with knee/hip Osteoarthritis undergoing a replacement surgery.

METHOD

Plasma samples of 30 (16 with knee Osteoarthritis and 14 with hip Osteoarthritis) patients have been collected before and 3 month after a knee/hip replacement in order to investigate the above stated aim of this study.

RESULT

Osteopontin levels did not decrease after 3 months of the surgery.

CONCLUSION

Osteopontin levels showed no significant reduction and therefore do not respond to replacement treatment.

Electrochemical aptasensor for human osteopontin detection using a DNA aptamer selected by SELEX

A DNA aptamer with affinity and specificity for human osteopontin (OPN), a potential breast cancer biomarker, was selected using the SELEX process, considering its homology rate and the stability of its secondary structures. This aptamer exhibited a satisfactory affinity towards OPN, showing dissociation constants lower than 2.5 nM. It was further used to develop a simple, label-free electrochemical aptasensor against OPN. The aptasensor showed good sensitivity towards OPN in standard solutions, being the square wave voltammetry (SWV), compared to the cyclic voltammetry, the most sensitive technique with detection and quantification limits of 1.4 ± 0.4 nM and 4.2 ± 1.1 nM, respectively. It showed good reproducibility and acceptable selectivity, exhibiting low signal interferences from other proteins, as thrombin, with 2.6-10 times lower current signals-off than for OPN. The aptasensor also successfully detected OPN in spiked synthetic human plasma. Using SWV, detection and quantification limits (1.3 ± 0.1 and 3.9 ± 0.4 nM) within the OPN plasma levels reported for patients with breast cancer (0.4-4.5 nM) or with metastatic or recurrent breast cancer (0.9-8.4 nM) were found. Moreover, preliminary assays, using a sample of human plasma, showed that the aptasensor and the standard ELISA method quantified similar OPN levels (2.2 ± 0.7 and 1.7 ± 0.1 nM, respectively). Thus, our aptasensor coupled with SWV represents a promising alternative for the detection of relevant breast cancer biomarkers.

Osteopontin is linked with AKT, FoxO1, and myostatin in skeletal muscle cells

Introduction: Osteopontin (OPN) polymorphisms are associated with muscle size and modify disease progression in Duchenne muscular dystrophy (DMD). We hypothesized that OPN may share a molecular network with myostatin (MSTN). Methods: Studies were conducted in the golden retriever (GRMD) and mdx mouse models of DMD. Follow‐up in‐vitro studies were employed in myogenic cells and the mdx mouse treated with recombinant mouse (rm) or human (Hu) OPN protein. Results: OPN was increased and MSTN was decreased and levels correlated inversely in GRMD hypertrophied muscle. RM‐OPN treatment led to induced AKT1 and FoxO1 phosphorylation, microRNA‐486 modulation, and decreased MSTN. An AKT1 inhibitor blocked these effects, whereas an RGD‐mutant OPN protein and an RGDS blocking peptide showed similar effects to the AKT inhibitor. RMOPN induced myotube hypertrophy and minimal Feret diameter in mdx muscle. Discussion: OPN may interact with AKT1/MSTN/FoxO1 to modify normal and dystrophic muscle. Muscle Nerve56: 1119–1127, 2017

Osteopontin is associated with disease severity and antiphospholipid syndrome in well characterised Swedish cases of SLE

Objective

The variety of disease phenotypes among patients with SLE challenges the identification of new biomarkers reflecting disease activity and/or organ damage. Osteopontin (OPN) is an extracellular matrix protein with immunomodulating properties. Although raised levels have been reported, the pathogenic implications and clinical utility of OPN as a biomarker in SLE are far from clear. Thus, the aim of this study was to characterise OPN in SLE.

Methods

Sera from 240 well-characterised adult SLE cases classified according to the American College of Rheumatology (ACR) and/or the Systemic Lupus International Collaborating Clinics (SLICC) criteria, and 240 population-based controls were immunoassayed for OPN. The SLE Disease Activity Index 2000 (SLEDAI-2K) was used to evaluate disease activity and the SLICC/ACR Damage Index (SDI) to detect damage accrual.

Results

Serum OPN levels were in average raised fourfold in SLE cases compared with the controls (p<0.0001). OPN correlated with SLEDAI-2K, especially in patients with a disease duration of <12 months (r=0.666, p=0.028). OPN was highly associated with SDI (p<0.0001), especially in the renal (p<0.0001), cardiovascular (p<0.0001) and malignancy (p=0.012) domains. Finally, OPN associated with coherent antiphospholipid syndrome (APS; p=0.009), and both clinical and laboratory criteria of APS had significant positive impact on OPN levels.

Conclusions

In this cross-sectional study, circulating OPN correlates with disease activity in recent-onset SLE, reflects global organ damage and associates with APS. Longitudinal studies to dissect whether serum OPN also precedes and predicts future organ damage are most warranted.

Osteopontin -- a promising biomarker for cancer therapy

Osteopontin (OPN), a multifunctional protein, has emerged as a potentially valuable biomarker for diagnosing and treating cancers. Recent research focuses on its involvement in tumor biology including the cell proliferation, survival, angiogenesis, invasion, and metastasis. Understanding the molecular mechanisms and pharmacological effects of OPN in cancer development could lead to new targets for improving cancer diagnosis and treatment. This review explains how the structurally conserved domains of OPN are associated with OPN signaling mediators and CD44, and how the conserved OPN domains determine biological functions. The authors have reviewed representative works of OPN expression in breast cancer and colorectal cancer to elucidate the relationship between OPN and cancer/tumor biology. It has also been shown that the prognostic sensitivity in non-small cell lung cancer, hepatocellular carcinoma, gastric cancer, and ovarian cancer improved compared to the individual marker when OPN was analyzed in conjunction with other markers. The therapeutic approaches based on OPN inhibitors are discussed to illustrate recent research progress. Previous clinical data has indicated that OPN has played a unique role in cancer development, but further investigation is required to understand the underlying mechanism. More clinical trials are also required to examine the applicability and efficacy of OPN inhibitors in cancer therapy.

The embryonic type of SPP1 transcriptional regulation is re-activated in glioblastoma

Osteopontin (SPP1, a secreted phosphoprotein 1) is primarily involved in immune responses, tissue remodelling and biomineralization. However, it is also overexpressed in many cancers and regulates tumour progression by increasing migration, invasion and cancer stem cell self-renewal. Mechanisms of SPP1 overexpression in gliomas are poorly understood. We demonstrate overexpression of two out of five SPP1 isoforms in glioblastoma (GBM) and differential isoform expression in glioma cell lines. Up-regulated SPP1 expression is associated with binding of the GLI1 transcription factor to the promoter and OCT4 (octamer-binding transcription factor 4) to the first SPP1 intron of the SPP1 gene in human glioma cells but not in non-transformed astrocytes. GLI1 knockdown reduced SPP1 mRNA and protein levels in glioma cells. GLI1 and OCT4 are known regulators of stem cell pluripotency. GBMs contain rare cells that express stem cell markers and display ability to self-renew. We reveal that SPP1 is overexpressed in glioma initiating cells defined by high rhodamine 123 efflux, sphere forming capacity and stemness marker expression. Forced differentiation of human glioma spheres reduced SPP1 expression. Knockdown of SPP1, GLI1 or CD44 with siRNAs diminished sphere formation. C6 glioma cells stably depleted of Spp1 displayed reduced sphere forming capacity and downregulated stemness marker expression. Overexpression of the wild type Spp1, but not Spp1 lacking a Cd44 binding domain, rescued cell ability to form spheres. Our findings show re-activation of the embryonic-type transcriptional regulation of SPP1 in malignant gliomas and point to the importance of SPP1-CD44 interactions in self-renewal and pluripotency glioma initiating cells.

Human osteopontin: Potential clinical applications in cancer (Review)

Human osteopontin (OPN) is a glycosylated phosphoprotein which is expressed in a variety of tissues in the body. In recent years, accumulating evidence has indicated that the aberrant expression of OPN is closely associated with tumourigensis, progression and most prominently with metastasis in several tumour types. In this review, we present the current knowledge on the expression profiles of OPN and its main splice variants in human cancers, as well as the potential implications in patient outcome. We also discuss its putative clinical application as a cancer biomarker and as a therapeutic target.

Osteopontin: its potential role in cancer of children and young adults

Objective: Osteopontin (OPN) is aglyco-phosphoprotein, involved in tissue remodeling, inflammation and boneresorption. In various adult neoplasms OPN was shown to correlate with cancer progression, invasiveness and metastasis. Aim: to define the role of OPN in malignancies of children and young adults. Material and methods: a structured PubMed and Google Scholar literature analysis based on reports published in English between I'1995 and XII'2015. Results: 14 studies (four on hematological malignancies, four on bone tumors, three on CNS tumors, two on dendritic proliferative diseases and one on renal tumors) were identified. Higher levels of serum and cerebro-spinal fluid OPN protein, and high expressions of OPN mRNA and SPP1 gene were present in more aggressive and advanced childhood malignancies. In children with acute lymphoblastic leukemia with CNS involvement and with atypical teratoid/rhabdoid tumor (AT/RT) and medulloblastoma, the serum and CSF OPN levels reflected tumor bulk and response to therapy, while in children with AT/RT and multisystem Langerhans cell histiocytosis with high-risk organs involvement, high OPN serum levels correlated with poorer survival. To the contrary, in osteosarcoma, high OPN mRNA and SPP1 gene expressions correlated with better survival and good response to chemotherapy. Conclusions: The literature review suggests that OPN may play important roles in the development and progression of selected cancers of children and young adults, including acute lymphoblastic leukemia, malignant gliomas, AT/RT and Langerhans cell histiocytosis. However, limited number of published studies prevents from definite concluding on the clinical utility of OPN as a marker of diagnosis, prognosis and treatment monitoring in these pediatric cancers. Further studies performed in more numerous groups of patients with particular types of cancers of children and young adults are warranted.

Spatiotemporal expression of osteopontin in the striatum of rats subjected to the mitochondrial toxin 3-nitropropionic acid correlates with microcalcification

Our aim was to elucidate whether osteopontin (OPN) is involved in the onset of mineralisation and progression of extracellular calcification in striatal lesions due to mitochondrial toxin 3-nitropropionic acid exposure. OPN expression had two different patterns when observed using light microscopy. It was either localised to the Golgi complex in brain macrophages or had a small granular pattern scattered in the affected striatum. OPN labelling tended to increase in number and size over a 2-week period following the lesion. Ultrastructural investigations revealed that OPN is initially localised to degenerating mitochondria within distal dendrites, which were then progressively surrounded by profuse OPN on days 7–14. Electron probe microanalysis of OPN-positive and calcium-fixated neurites indicated that OPN accumulates selectively on the surfaces of degenerating calcifying dendrites, possibly via interactions between OPN and calcium. In addition, 3-dimensional reconstruction of OPN-positive neurites revealed that they are in direct contact with larger OPN-negative degenerating dendrites rather than with fragmented cell debris. Our overall results indicate that OPN expression is likely to correlate with the spatiotemporal progression of calcification in the affected striatum, and raise the possibility that OPN may play an important role in the initiation and progression of microcalcification in response to brain insults.

Osteopontin-metallothionein I/II interactions in experimental autoimmune encephalomyelitis

Osteopontin (OPN), an extracellular matrix (ECM) glyco-phosphoprotein, plays an important role in autoimmune-mediated demyelinating diseases, including multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). As an integrin and CD44 binding protein it participates in bidirectional communication between the ECM and target cells and affects transduction pathways that maintain neuronal and immune cell homeostasis. Its biological activity is also heavily influenced by microenvironment, which stimulates the cleavage of OPN and changes its functions. In this study we estimated the expression profile of OPN in neural tissues of DA rats during the first relapse of chronic relapsing EAE and investigated the relationship of OPN to metallothionein I+II (MTs), which play pivotal role in zinc-related cell homeostasis and in protection of CNS against cytokine-induced injury. The data showed that in EAE rats OPN mRNA and protein levels increased concurrently with the transcription of MTs and that within the spinal cord (SC) lysates EAE-afflicted rats had a higher content of OPN fragments of low molecular weight than untreated and CFA-treated rats. The expression of OPN and MTs was upregulated on ependymal, lymphoid and astroglial cells and on multiple αvβ3+ neurons in SC and in the brain (cortex, white matter, hippocampus, and cerebellum). Besides, multiple cells co-expressed OPN and MTs. Granular OPN signals were detected in secretory vesicles of Golgy (αvβ3 neurons) and in patches adjacent to the plasma membrane (subventricular zone). The findings imply that in demyelinating lesions are generated proteolytic OPN fragments and that OPN/MT interactions contribute to tissue remodeling during an autoimmune attack.

Molecular Imaging of Vulnerable Atherosclerotic Plaques in Vivo with Osteopontin-Specific Upconversion Nanoprobes

Owing to the high mortality rate of cardiovascular diseases, developing novel noninvasive diagnostic methods becomes urgent and mandatory. It is well-known that the rupture of vulnerable plaques directly leads to deadly consequences. However, differentiating vulnerable plaques from stable plaques remains challenging in the clinic. In the current study, osteopontin (OPN), a secreted biomarker associated with macrophages and foamy macrophages, was selected as a target for identifying the vulnerable plaques. A dual modality imaging probe was constructed by covalently attaching an OPN antibody to NaGdF₄:Yb,Er@NaGdF₄ upconversion nanoparticles. Upon intravenous injection of the resulting probes, upconversion optical imaging was performed to visualize the plaques induced by altering the shear stress in carotid arteries of a mouse model. The imaging studies revealed that the signals of vulnerable and stable plagues induced by lowered shear stress and oscillatory shear stress, respectively, presented significantly different signal intensities, implying that the current probe and imaging strategy are potentially useful for a precise diagnosis of atherosclerosis plaques.

Elucidation of mechanism of blood-brain barrier damage for prevention and treatment of vascular dementia

It is well-known that the blood-brain barrier (BBB) plays significant roles in transporting intravascular substances into the brain. The BBB in cerebral capillaries essentially impedes the influx of intravascular compounds from the blood to the brain, while nutritive substances, such as glucose, can be selectively transported through several types of influx transporters in endothelial cells. In the choroid plexus, intravascular substances can invade the parenchyma as fenestrations exist in endothelial cells of capillaries. However, the substances cannot invade the ventricles easily as there are tight junctions between epithelial cells in the choroid plexus. This restricted movement of the substances across the cytoplasm of the epithelial cells constitutes a blood-cerebrospinal fluid barrier (BCSFB). In the brain, there are circumventricular organs, in which the barrier function is imperfect in capillaries. Accordingly, it is reasonable to consider that intravascular substances can move in and around the parenchyma of the organs. Actually, it was reported in mice that intravascular substances moved in the corpus callosum, medial portions of the hippocampus, and periventricular areas via the subfornical organs or the choroid plexus. Regarding pathways of intracerebral interstitial and cerebrospinal fluids to the outside of the brain, two representative drainage pathways, or perivascular drainage and glymphatic pathways, are being established. The first is the pathway in a retrograde direction to the blood flow through the basement membrane in walls of cerebral capillaries, the tunica media of arteries, and the vessels walls of the internal carotid artery. The second is in an anterograde direction to blood flow through the para-arterial routes, aquaporin 4-dependent transport through the astroglial cytoplasm, and para-venous routes, and then the fluids drain into the subarachnoid CSF. These fluids are finally considered to drain into the cervical lymph nodes or veins. These clearance pathways may play a role in maintenance of the barrier in the entire brain. Obstruction of the passage of fluids through the perivascular drainage and glymphatic pathways as well as damage of the BBB and BCSFB may induce several kinds of brain disorders, such as vascular dementia. In this review, we focus on the relationship between damage of the barriers and the pathogenesis of vascular dementia and introduce recent findings including our experimental data using animal models.

Age-Related Loss in Bone Mineral Density of Rats Fed Lifelong on a Fish Oil-Based Diet Is Avoided by Coenzyme Q10 Addition

During aging, bone mass declines increasing osteoporosis and fracture risks. Oxidative stress has been related to this bone loss, making dietary compounds with antioxidant properties a promising weapon. Male Wistar rats were maintained for 6 or 24 months on diets with fish oil as unique fat source, supplemented or not with coenzyme Q10 (CoQ10), to evaluate the potential of adding this molecule to the n-3 polyunsaturated fatty acid (n-3 PUFA)-based diet for bone mineral density (BMD) preservation. BMD was evaluated in the femur. Serum osteocalcin, osteopontin, receptor activator of nuclear factor-κB ligand, ostroprotegerin, parathyroid hormone, urinary F₂-isoprostanes, and lymphocytes DNA strand breaks were also measured. BMD was lower in aged rats fed a diet without CoQ10 respect than their younger counterparts, whereas older animals receiving CoQ10 showed the highest BMD. F₂-isoprostanes and DNA strand breaks showed that oxidative stress was higher during aging. Supplementation with CoQ10 prevented oxidative damage to lipid and DNA, in young and old animals, respectively. Reduced oxidative stress associated to CoQ10 supplementation of this n-3 PUFA-rich diet might explain the higher BMD found in aged rats in this group of animals.

Embracing the complexity of matricellular proteins: the functional and clinical significance of splice variation

Matricellular proteins influence wide-ranging fundamental cellular processes including cell adhesion, migration, growth and differentiation. They achieve this both through interactions with cell surface receptors and regulation of the matrix environment. Many matricellular proteins are also associated with diverse clinical disorders including cancer and diabetes. Alternative splicing is a precisely regulated process that can produce multiple isoforms with variable functions from a single gene. To date, the expression of alternate transcripts for the matricellular family has been reported for only a handful of genes. Here we analyse the evidence for alternative splicing across the matricellular family including the secreted protein acidic and rich in cysteine (SPARC), thrombospondin, tenascin and CCN families. We find that matricellular proteins have double the average number of splice variants per gene, and discuss the types of domain affected by splicing in matricellular proteins. We also review the clinical significance of alternative splicing for three specific matricellular proteins that have been relatively well characterised: osteopontin (OPN), tenascin-C (TNC) and periostin. Embracing the complexity of matricellular splice variants will be important for understanding the sometimes contradictory function of these powerful regulatory proteins, and for their effective clinical application as biomarkers and therapeutic targets.

Osteopontin regulates macrophage activation and osteoclast formation in hypertensive patients with vascular calcification

Vascular calcification (VC) is a highly regulated ectopic mineral deposition process involving immune cell infiltration in the vasculatures, which has been recognized to be promoted by hypertension. The matricellular glycoprotein osteopontin (OPN) is strongly induced in myeloid cells as a potential inflammatory mediator of vascular injury. This study aims to examine whether OPN is involved in the regulation of macrophage activation and osteoclast formation in hypertensive subjects with VC. We firstly found an increased proportion of CD11c+CD163- pro-inflammatory peripheral monocytes in hypertensive subjects with VC compared to those without VC by flow cytometric analysis. Primary cultured macrophages from hypertensive subjects with VC also showed altered expression profile of inflammatory factors and higher serum OPN level. Exogenous OPN promoted the differentiation of peripheral monocytes into an alternative, anti-inflammatory phenotype, and inhibited macrophage-to-osteoclast differentiation from these VC patients. In addition, calcified vessels showed increased osteoclasts accumulation accompanied with decreased macrophages infiltration in the of hypertensive subjects. Taken together, these demonstrated that OPN exerts an important role in the monocytes/macrophage phenotypic differentiation from hypertensive patients with VC, which includes reducing inflammatory factor expression and attenuating osteoclast formation.

Elevated 20-HETE impairs coronary collateral growth in metabolic syndrome via endothelial dysfunction

Coronary collateral growth (CCG) is impaired in metabolic syndrome (MetS). microRNA-145 (miR-145-Adv) delivery to our rat model of MetS (JCR) completely restored and neutrophil depletion significantly improved CCG. We determined whether low endogenous levels of miR-145 in MetS allowed for elevated production of 20-hydroxyeicosatetraenoic acid (20-HETE), which, in turn, resulted in excessive neutrophil accumulation and endothelial dysfunction leading to impaired CCG. Rats underwent 0-9 days of repetitive ischemia (RI). RI-induced cardiac CYP4F (neutrophil-specific 20-HETE synthase) expression and 20-HETE levels were increased (4-fold) in JCR vs. normal rats. miR-145-Adv and 20-HETE antagonists abolished and neutrophil depletion (blocking antibodies) reduced (~60%) RI-induced increases in CYP4F expression and 20-HETE production in JCR rats. Impaired CCG in JCR rats (collateral-dependent blood flow using microspheres) was completely restored by 20-HETE antagonists [collateral-dependent zone (CZ)/normal zone (NZ) flow ratio was 0.76 ± 0.07 in JCR + 20-SOLA, 0.84 ± 0.05 in JCR + 20-HEDGE vs. 0.11 ± 0.02 in JCR vs. 0.84 ± 0.03 in normal rats]. In JCR rats, elevated 20-HETE was associated with excessive expression of endothelial adhesion molecules and neutrophil infiltration, which were reversed by miR-145-Adv. Endothelium-dependent vasodilation of coronary arteries, endothelial nitric oxide synthase (eNOS) Ser1179 phosphorylation, eNOS-dependent NO^·- production and endothelial cell survival were compromised in JCR rats. These parameters of endothelial dysfunction were completely reversed by 20-HETE antagonism or miR-145-Adv delivery, whereas neutrophil depletion resulted in partial reversal (~70%). We conclude that low miR-145 in MetS allows for increased 20-HETE, mainly from neutrophils, which compromises endothelial cell survival and function leading to impaired CCG. 20-HETE antagonists could provide viable therapy for restoration of CCG in MetS.NEW & NOTEWORTHY Elevated 20-hydroxyeicosatetraenoic acid (20-HETE) impairs coronary collateral growth (CCG) in metabolic syndrome by eliciting endothelial dysfunction and apoptosis via excessive neutrophil infiltration. 20-HETE antagonists completely restore coronary collateral growth in metabolic syndrome. microRNA-145 (miR-145) is an upstream regulator of 20-HETE production in metabolic syndrome; low expression of miR-145 in metabolic syndrome promotes elevated production of 20-HETE.

A humanized osteopontin mouse model and its application in immunometabolic obesity studies

Osteopontin (OPN) is a multifunctional protein involved in several inflammatory processes and pathogeneses including obesity-related disorders and cancer. OPN binds to a variety of integrin receptors and CD44 resulting in a proinflammatory stimulus. Therefore, OPN constitutes a novel interesting target to develop new therapeutic strategies, which counteract OPN's proinflammatory properties. We established a humanized SPP1 (hSPP1) mouse model and evaluated its suitability as a model for obesity and insulin resistance. Unchallenged hSPP1 animals did not significantly differ in body weight and gross behavioral properties compared to wild-type (WT) animals. High-fat diet-challenged hSPP1 similarly developed obesity and inflammation, whereas insulin resistance was markedly changed. However, OPN expression profile in tissues was significantly altered in hSPP1 compared to WT depending on the diet. In conclusion, we developed a versatile humanized model to study the action of OPN in vivo and to develop strategies that target human OPN in a variety of pathologies.

Update on Inflammatory Biomarkers and Treatments in Ischemic Stroke

After an acute ischemic stroke (AIS), inflammatory processes are able to concomitantly induce both beneficial and detrimental effects. In this narrative review, we updated evidence on the inflammatory pathways and mediators that are investigated as promising therapeutic targets. We searched for papers on PubMed and MEDLINE up to August 2016. The terms searched alone or in combination were: ischemic stroke, inflammation, oxidative stress, ischemia reperfusion, innate immunity, adaptive immunity, autoimmunity. Inflammation in AIS is characterized by a storm of cytokines, chemokines, and Damage-Associated Molecular Patterns (DAMPs) released by several cells contributing to exacerbate the tissue injury both in the acute and reparative phases. Interestingly, many biomarkers have been studied, but none of these reflected the complexity of systemic immune response. Reperfusion therapies showed a good efficacy in the recovery after an AIS. New therapies appear promising both in pre-clinical and clinical studies, but still need more detailed studies to be translated in the ordinary clinical practice. In spite of clinical progresses, no beneficial long-term interventions targeting inflammation are currently available. Our knowledge about cells, biomarkers, and inflammatory markers is growing and is hoped to better evaluate the impact of new treatments, such as monoclonal antibodies and cell-based therapies.

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.

MRI/optical dual-modality imaging of vulnerable atherosclerotic plaque with an osteopontin-targeted probe based on Fe3O4 nanoparticles

Rupture of vulnerable atherosclerotic plaque is the major pathological cause of luminal thrombosis in acute coronary syndromes. Since foamy macrophages have been identified as a prominent component in vulnerable atherosclerotic lesions and osteopontin (OPN) is reported to be highly expressed in foamy macrophages, OPN could be a potential target for vulnerable atherosclerotic plaque imaging. The current study designed an OPN-specific MRI/optical dual-modality probe to detect vulnerable plaques. Fluorescence imaging revealed that 24 h after injection of the Cy5.5-OPN-DMSA-MNPs (COD-MNPs), the atherosclerotic plaques in carotid artery exhibited significant higher signals in high fat diet (HFD) fed mice in comparison to the group injected with Cy5.5-IgG-DMSA-MNPs (CID-MNPs) or normal diet fed group injected with COD-MNPs (1.87 ± 0.19 × 10¹⁰ vs. 0.74 ± 0.04 × 10¹⁰, 0.73 ± 0.03 × 10¹⁰ p/sec/cm²/sr, P < 0.05). Meanwhile, MRI displayed stronger T₂ contrast enhancement 24 h post-injection at the area of atherosclerotic plaques in the carotid of HFD fed group injected with COD-MNPs than group injected with CID-MNPs or normal diet fed group injected with COD-MNPs (post/pre signal ratio: 0.64 ± 0.04 vs. 0.95 ± 0.02, 0.98 ± 0.01, P < 0.05). As a dual-modality molecular probe, the resulting COD-MNPs conjugates exhibit promising potentials for noninvasive detection of vulnerable atherosclerotic plaque in vivo.

Osteopontin (OPN/SPP1) isoforms collectively enhance tumor cell invasion and dissemination in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) is often diagnosed at an advanced stage, thus understanding the molecular basis for EAC invasion and metastasis is critical. Here we report that SPP1/OPN was highly overexpressed in primary EACs and intracellularly localized to tumor cells. We further demonstrate that all known OPN isoforms (OPNa, b, c, 4 and 5) were frequently co-overexpressed in primary EACs. Distinct pro-invasion and dissemination phenotypes of isoform-specific OPNb and OPNc stable transfectants were observed. Expression of OPNb significantly enhanced cell migration and adhesion to laminin. In contrast, OPNc cells showed significantly decreased cell migration yet increased cell detachment. Enhanced invasion, both in vitro and in vivo, was observed for OPNb- but not OPNc-expressing cells. Inhibition of RGD integrins, one family of OPN receptors, attenuated OPNb cell migration, abrogated OPNb cell adhesion and significantly reduced OPNb cell clonogenic survival but did not affect OPNc phenotypes, indicating that OPNb but not OPNc acts through integrin-dependent signaling. Differential expression of vimentin, E-cadherin and β-catenin in OPN stable cells may account for the variation in cell adhesion and detachment between these isoforms. We conclude that while all OPN isoforms are frequently co-overexpressed in primary EACs, isoforms OPNb and OPNc enhance invasion and dissemination through collective yet distinct mechanisms.

Plasma thrombin-cleaved osteopontin as a potential biomarker of acute atherothrombotic ischemic stroke

We investigated whether thrombin-cleaved osteopontin N-terminal is useful as a blood biomarker of acute atherothrombotic ischemic stroke. Acute ischemic stroke patients were prospectively evaluated with brain magnetic resonance imaging and cardiac evaluations for etiological diagnosis according to the Trial of Org 10172 in Acute Stroke Treatment classification. They were divided into the atherothrombotic and non-atherothrombotic groups. Thrombin-cleaved osteopontin N-terminal, osteopontin, matrix metalloproteinase-9, S100B, C-reactive protein and D-dimer levels were measured from blood samples collected at admission. After excluding patients who met the exclusion criteria or had stroke of other/undetermined etiology, 60 of the 100 patients initially enrolled were included in the final analysis. The ischemic stroke subtypes were atherothrombotic (n=28, 46.7%), cardioembolic (n=19, 31.7%) and lacunar (n=13, 21.7%). Thrombin-cleaved osteopontin N-terminal and matrix metalloproteinase-9 levels were significantly higher in the atherothrombotic than in the non-atherothrombotic group (median (interquartile range): 5.83  (0.0-8.6 ) vs. 0.0  (0.0-3.3) pmol l^-1, P=0.03 and 544   (322-749 ) vs. 343   (254-485) ng ml^-1, P=0.01, respectively). After adjustment for the prevalence of hypertension, diabetes and dyslipidemia, thrombin-cleaved osteopontin N-terminal levels of >5.47 pmol l^-1 (odds ratio, 16.81; 95% confidence interval, 3.53-80.10) and matrix metalloproteinase-9 levels of >605.5 ng ml^-1 (6.59; 1.77-24.60) were identified as independent predictors of atherothrombosis. Within 3 h from stroke onset, only thrombin-cleaved osteopontin N-terminal independently predicted atherothrombosis and thus may add valuable, time-sensitive diagnostic information in the early evaluation of ischemic stroke, especially the atherothrombotic subtype.

Myocardial Expression Analysis of Osteopontin and Its Splice Variants in Patients Affected by End-Stage Idiopathic or Ischemic Dilated Cardiomyopathy

Osteopontin (OPN) is a phosphoglycoprotein of cardiac extracellular matrix and it is still poorly defined whether its expression changes in failing heart of different origin. The full-length OPN-a and its isoforms (OPN-b, OPN-c) transcriptomic profile were evaluated in myocardium of patients with dilated or ischemic cardiomyopathy (DCM n = 8; LVEF% = 17.5±3; ICM n = 8; LVEF% = 19.5±5.2) and in auricle of valvular patients (VLP n = 5; LVEF%≥50), by Real-time PCR analysis. OPN-a and thrombin mRNA levels resulted significantly higher in DCM compared to ICM patients (DCM:31.3±7.4, ICM:2.7±1.1, p = 0.0002; DCM:19.1±4.9, ICM:5.4±2.2, p = 0.007, respectively). Although both genes’ mRNA levels increased in patients with LVEF<50% (DCM+ICM) with respect to VLP with LVEF>50%, a significant increase in OPN (p = 0.0004) and thrombin (p = 0.001) expression was observed only in DCM. In addition, a correlation between OPN-a and thrombin was found in patients with LVEF<50% (r = 0.6; p = 0.003). The mRNA pattern was confirmed by OPN-a cardiac protein concentration (VLP:1.127±0.26; DCM:1.29±0.22; ICM:1.00±0.077 ng/ml). The OPN splice variants expression were detectable only in ICM (OPN-b: 0.357±0.273; OPN-c: 0.091±0.033) and not in DCM patients. A significant correlation was observed between collagen type I, evaluated by immunohistochemistry analysis, and both OPN-a mRNA expression (r = 0.87, p = 0.002) and OPN protein concentrations (r = 0.77, p = 0.016). Concluding, OPN-a and thrombin mRNA resulted dependent on the origin of heart failure while OPN-b and OPN-c highlighted a different expression for DCM and ICM patients, suggesting their correlation with different clinical-pathophysiological setting.

Tumor-associated macrophages induce capillary morphogenesis of lymphatic endothelial cells derived from human gastric cancer

Tumor lymphangiogenesis is a major prognostic indicator of gastric cancer. Tumor‐induced inflammation has been shown to attract tumor‐associated macrophages that affect lymphangiogenesis. However, detailed mechanisms of macrophage‐induced lymphangiogenesis have not been elucidated. Here, we evaluated the interaction between tumor‐associated macrophages and lymphatic endothelial cells (LECs) derived from lymph nodes (LNs) of human gastric cancer. Lymphatic endothelial cells were directly or indirectly cocultured with macrophages from healthy human blood, with or without the supernatant of the gastric cancer cell line, OCUM‐12. We analyzed the effect of cancer pretreated macrophages and of macrophages from metastatic LNs of gastric cancer on LECs. We observed morphological changes of LECs in coculture and assessed the gene expression of possible lymphangiogenic molecules of macrophages and LECs after contact coculture, and of cancer pretreated macrophages, by quantitative RT‐PCR. Specimens of metastatic LN of gastric cancer were immunofluorescently stained. We found that tubulogenesis of LECs was observed only in the contact coculture model. OCUM‐12 cells promoted macrophage‐induced tubulogenesis of LECs. Relative gene expression of MMP and adhesion molecules was significantly upregulated in both capillary‐forming LECs and cocultured macrophages. Cancer pretreated macrophages upregulated lymphangiogenic factors including inflammatory cytokines, MMPs, adhesion molecules, and vascular endothelial growth factor‐C. Blocking of intercellular adhesion molecule‐1 and macrophage activation suppressed tubulogenesis of LECs. Immunohistochemistry showed macrophages localized around lymphatic vessels. Our results suggested that interaction between LECs and macrophages may be an important initial step of tumor lymphangiogenesis developing LN metastasis. Understanding of its mechanisms could be useful for future therapeutics of gastric cancer.

Genetic variations in the osteopontin promoters T-443C and G-156GG increase carotid intima-media thickness

Carotid intima-media thickness (CIMT) is a clear predictor of atherosclerosis. The increase of CIMT is affected by mutations in the osteopontin (OPN) promoters. The purpose of this study was to examine genetic variations in OPN promoters T-443C and G-156GG, identified in Javanese children with ischemic stroke parents, and to investigate their relationship with the increase of CIMT. A case-control analytic study was performed on 20 case and 12 control samples. Case samples were Javanese children aged between 10 to 21 years with ischemic stroke parents. Control samples were children with healthy parents. Mutations of T-443C and G-156GG were determined by employing polymerase chain reaction. Results of sequencing were analyzed using CLC Main Workbench 6.0. CIMT was defined using ultrasound. Genetic variations of T-443C were identified in six samples. Likewise, genetic variations of G-156GG were identified in six samples. Genetic variations in the OPN promoters T-443C and G-156GG were not potential risk factors in an increase of CIMT (P=0.654 and P=0.654). This study proves that genetic variations could be identified at the points of T-443C and G-156GG in children with ischemic stroke parents. Although statistically insignificant, the tendency to increase CIMT occurs in children with genetic variations. Children with ischemic stroke parents have thicker CIMT than children of healthy parents.

Distribution of alkaline phosphatase, osteopontin, RANK ligand and osteoprotegerin in calcified human carotid atheroma

Ectopic vascular calcification is a significant component of atherosclerotic disease. Osteopontin (OPN), Osteoprotegerin (OPG), Receptor Activator of NFκB Ligand (RANKL), and alkaline phosphatase (ALP) are each thought to play central roles in the calcification or demineralization of atherosclerotic lesions. Abnormalities in the balance of these proteins may lead to perturbations in bone remodeling and arterial calcification. The purpose of this study was to measure the distribution of these proteins in human carotid lesions and to elucidate possible mechanism(s) whereby they control the deposition or depletion of arterial calcification. Thirty-three patients who had undergone carotid endarterectomy (CEA) within the previous 18 months and 11 control patients were enrolled. CEA specimens were analyzed by EBCT for calcification content in terms of Agatston (AGAT) and Volume scores. CEA specimens were then cut into 5 mm segments which were homogenized and extracted. Extracts were analyzed for tissue levels of calcium, phosphorus, ALP, OPN, RANKL, and OPG. Fasting blood samples were analyzed for the same components. In CEA tissue segments, the calcification levels (CHA AGAT) were inversely associated with the levels of OPG (r = -0.432/-0.579, p < 0.05) and positively associated with the levels of RANKL (r = 0.332/0.415, p < 0.05). In turn, the tissue levels of OPG were associated with homologous serum levels of OPG (r = 0.820/0.389, p < 0.001), and the tissue levels of RANKL were associated with the serum levels of homologous RANKL (r = 0.739/0.666, p < 0.0001). This study suggests that serum levels of OPG and RANKL may be useful biomarkers for estimating the degree of calcification in carotid atherosclerotic lesions.

In Vitro Cytokine Expression and In Vivo Healing and Inflammatory Response to a Collagen-Coated Synthetic Bone Filler

The goal of the present work was to investigate the relationship between in vivo healing and inflammatory response and in vitro cytokine expression by macrophages of a synthetic bone filler (25% hydroxylapatite-75% β-tricalcium phosphate) bearing a surface nanolayer of collagen. A clinically accepted, state-of-the-art xenograft material was used as a “negative control,” that is, as a material that provides the correct clinical response for the intended use. In vitro data show that both materials exert a very low stimulation of proinflammatory cytokines by macrophages, and this was confirmed by the very mild inflammatory response detected in in vivo tests of local response in a rabbit model. Also, in vitro findings suggest a different mechanism of healing for the test and the control material, with a higher regenerative activity for the synthetic, resorbable filler, as confirmed by in vivo observation and literature reports. Thus, the simple in vitro model adopted provides a reasonable forecast of in vivo results, suggesting that new product development can be guided by in vitro tuning of cell-materials interactions.

Polycystic ovary syndrome is associated with increased osteopontin levels

OBJECTIVE

Osteopontin (OPN) is a multi-functional secreted glycoprotein that plays a crucial role in glucose metabolism and inflammatory process. Growing evidence suggests that there is a link between OPN and ovarian function. However, no such link has yet been found for OPN in polycystic ovary syndrome (PCOS). Our aim was to ascertain whether circulating OPN levels are altered in women with PCOS and to determine whether OPN levels differ between the follicular phase and mid-cycle of the menstrual cycle in eumenorrheic women.

DESIGN AND METHODS

In total, 150 women with PCOS and 150 age- and BMI-matched controls without PCOS were recruited for this prospective observational study. OPN levels were measured using ELISA. Metabolic parameters were also determined.

RESULTS

Circulating OPN levels were significantly elevated in PCOS women compared with controls (69.12±31.59  ng/ml vs 42.66±21.28  ng/ml; P<0.001). OPN levels were significantly higher at mid-cycle than in the follicular phase in eumenorrheic women. OPN was positively correlated with BMI, homeostasis model assessment of insulin resistance (HOMA-IR), free testosterone, and high sensitivity C-reactive protein (hs-CRP). Multivariate logistic regression analyses revealed that the odds ratio (OR) for PCOS was 3.64 for patients in the highest quartile of OPN compared with those in the lowest quartile (OR=3.64; 95% CI=2.42-5.57; P=0.011). Our findings indicate that BMI, HOMA-IR, hs-CRP, and free testosterone are independent factors influencing serum OPN levels and that OPN is an independent predictor for HOMA-IR.

CONCLUSION

PCOS is associated with increased OPN levels.