Elevated osteopontin levels in patients with peripheral arterial disease

Association of serum Spp1 levels with disease progression in ALS and SBMA

OBJECTIVE

In comparison with amyotrophic lateral sclerosis (ALS), the contribution of neuroinflammation in spinobulbar muscular atrophy (SBMA) has been less explored. We investigated the role of neuroinflammation in the pathogenesis of ALS and SBMA by analyzing systemic inflammatory markers and osteopontin (Spp1).

METHODS

This study involved 105 ALS, 77 SBMA, and 55 healthy controls. We measured their systemic inflammatory markers, serum Spp1, and cytokine levels (interferon-γ, interleukin [IL]-1β, IL-6, IL-8, IL-10, tumor necrosis factor-α, and IL-17A), investigated correlations between Spp1 levels and clinical features, and evaluated ALS survival rates according to Spp1 levels.

RESULTS

In the ALS group, systemic inflammatory markers were significantly higher than in the control and SBMA groups. Spp1 levels were observed to be higher in ALS patients, but the difference was not statistically significant among the study groups. Cytokine profiles were comparable. In ALS, higher Spp1 levels were correlated with lower ALS Functional Rating Scale-Revised (ALSFRS-R) scores (r = -0.25, p = 0.02) and faster disease progression rate (r = 0.37, p < 0.001). After adjusting for other prognostic indicators, high Spp1 levels were independently associated with shorter survival in ALS patients (hazard ratio 13.65, 95% confidence interval 2.57-72.53, p < 0.01).

INTERPRETATION

Neuroinflammation does not appear to be a primary contributor to the pathogenesis of SBMA. Serum Spp1 levels may serve as a reliable biomarker for disease progression and prognosis in ALS. These findings expand our understanding of these two distinct motor neuron disorders and offer a potential biomarker for future studies.

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

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

Microglia-Derived Spp1 Promotes Pathological Retinal Neovascularization via Activating Endothelial Kit/Akt/mTOR Signaling

Pathological retinal neovascularization (RNV) is the main character of ischemic ocular diseases, which causes severe visual impairments. Though retinal microglia are well acknowledged to play important roles in both physiological and pathological angiogenesis, the molecular mechanisms by which microglia communicates with endothelial cells (EC) remain unknown. In this study, using single-cell RNA sequencing, we revealed that the pro-inflammatory secreted protein Spp1 was the most upregulated gene in microglia in the mouse model of oxygen-induced retinopathy (OIR). Bioinformatic analysis showed that the expression of Spp1 in microglia was respectively regulated via nuclear factor-kappa B (NF-κB) and hypoxia-inducible factor 1α (HIF-1α) pathways, which was further confirmed through in vitro assays using BV2 microglia cell line. To mimic microglia-EC communication, the bEnd.3 endothelial cell line was cultured with conditional medium (CM) from BV2. We found that adding recombinant Spp1 to bEnd.3 as well as treating with hypoxic BV2 CM significantly enhanced EC proliferation and migration, while Spp1 neutralizing blocked those CM-induced effects. Moreover, RNA sequencing of BV2 CM-treated bEnd.3 revealed a significant downregulation of Kit, one of the type III tyrosine kinase receptors that plays a critical role in cell growth and activation. We further revealed that Spp1 increased phosphorylation and expression level of Akt/mTOR signaling cascade, which might account for its pro-angiogenic effects. Finally, we showed that intravitreal injection of Spp1 neutralizing antibody attenuated pathological RNV and improved visual function. Taken together, our work suggests that Spp1 mediates microglia-EC communication in RNV via activating endothelial Kit/Akt/mTOR signaling and is a potential target to treat ischemic ocular diseases.

Association of serum levels of osteopontin and osteoprotegerin with adverse outcomes after endovascular revascularisation in peripheral artery disease

Background

Osteoprotegerin (OPG) and osteopontin (OPN) are vascular calcification inhibitors with a known role in the atherosclerotic and inflammatory process. We investigated their relationship with adverse outcomes (restenosis/adverse cardiovascular events) after endovascular revascularisation of patients with peripheral arterial disease (PAD).

Methods

203 consecutive patients were enrolled in the PAD group (PADG) and 78 age and sex-matched subjects with less than two cardiovascular risk factors served as control group (COG). PADG underwent standard medical assessment at baseline and 12 months after the procedure. During follow up major adverse cardiovascular events (MACEs) including arterial restenosis with need for reintervention were documented and the PADG was divided accordingly into two subgroups.

Results

During 12-month follow-up, 82 MACE were recorded (MACE subgroup). The rest of 124 PAD patients remained free of MACE (non-MACE subgroup). At baseline, OPG (9.89 ± 2.85 ng/ml vs 3.47 ± 1.95 ng/ml, p < 0.001) and OPN (79.99 ± 38.29 ng/ml vs 35.21 ± 14.84 ng/ml, p < 0.001) levels were significantly higher in PADG compared to COG, as well as in MACE subgroup compared to non-MACE subgroup (13.29 ± 3.23 ng/ml vs 10.86 ± 3 ng/ml and 96.45 ± 40.12 ng/ml vs 78.1 ± 38.29 ng/ml, respectively). An independent association of PAD with OPG and OPN was found in the whole patient cohort. Although OPG and OPN were significantly related to MACE incidence in the univariate analysis, multiple logistic regression analysis failed to detect any independent predictor of MACE within the PADG.

Conclusion

Baseline high OPG and OPN levels were independently associated with PAD presence. Even higher levels of those biomarkers were detected among PAD patients with MACE, however, their prognostic role should be further clarified.

Ustekinumab reduces serum protein levels associated with cardiovascular risk in psoriasis vulgaris

Psoriasis increases the risk of cardiovascular disease (CVD). Biomarkers for cardiovascular (CV) risk stratification in psoriasis are lacking, and the effects of psoriasis biologics on CV risk reduction remain unclear. The goal of this study was to identify biomarkers of CV risk in psoriasis blood that are reduced by ustekinumab. We quantified 276 inflammatory and CV-related serum proteins with Olink's multiplex assay in 10 psoriasis patients (vs. 18 healthy controls) and after 12 weeks of ustekinumab treatment. For each protein down-regulated after treatment, the literature was reviewed for studies assessing the protein's association with CVD. Data were collected from each study to calculate CV risk thresholds for each protein, which were compared with protein levels in psoriasis patients before and after treatment. Our results showed that 43 out of 276 proteins were down-regulated after treatment, 25 of which were initially up-regulated at baseline (vs. controls, all p-values ≤0.1). 8 down-regulated proteins were initially elevated above thresholds associated with enhanced CV risk in the literature (myeloperoxidase, C-X-C motif chemokine 10, E-selectin, interleukin-6, cystatin B, von Willebrand factor, tumor necrosis factor receptor 1 and N-terminal prohormone brain natriuretic peptide). Treatment lowered these proteins to below their risk thresholds, except for IL-6, which was lowered but remained at its risk threshold despite successful psoriasis skin treatment. In summary, 12 weeks of ustekinumab treatment reduced serum proteins present at levels associated with CV risk in psoriasis patients. Further studies can evaluate these proteins as potential ustekinumab-modulated biomarkers of CV risk in psoriasis and the impact of ustekinumab on CV risk reduction.

p38 MAPK priming boosts VSMC proliferation and arteriogenesis by promoting PGC1α-dependent mitochondrial dynamics

Vascular smooth muscle cell (VSMC) proliferation is essential for arteriogenesis to restore blood flow after artery occlusion, but the mechanisms underlying this response remain unclear. Based on our previous findings showing increased VSMC proliferation in the neonatal aorta of mice lacking the protease MT4-MMP, we aimed at discovering new players in this process. We demonstrate that MT4-MMP absence boosted VSMC proliferation in vitro in response to PDGF-BB in a cell-autonomous manner through enhanced p38 MAPK activity. Increased phospho-p38 in basal MT4-MMP-null VSMCs augmented the rate of mitochondrial degradation by promoting mitochondrial morphological changes through the co-activator PGC1α as demonstrated in PGC1α^−/− VSMCs. We tested the in vivo implications of this pathway in a novel conditional mouse line for selective MT4-MMP deletion in VSMCs and in mice pre-treated with the p38 MAPK activator anisomycin. Priming of p38 MAPK activity in vivo by the absence of the protease MT4-MMP or by anisomycin treatment led to enhanced arteriogenesis and improved flow recovery after femoral artery occlusion. These findings may open new therapeutic opportunities for peripheral vascular diseases.

Analysis of differentially expressed genes and signaling pathways involved in atherosclerosis and chronic obstructive pulmonary disease

Atherosclerosis is an important medical and social problem, and the keys to solving this problem are still largely unknown. A common situation in real clinical practice is the comorbid course of atherosclerosis with chronic obstructive pulmonary disease (COPD). Diseases share some common risk factors and may be closely linked pathogenetically.

METHODS

Bioinformatics analysis of datasets from Gene Expression Omnibus (GEO) was performed to examine the gene ontology (GO) of common differentially expressed genes (DEGs) in COPD and peripheral arterial atherosclerosis. DEGs were identified using the limma R package with the settings p < 0.05, corrected using the Benjamini & Hochberg algorithm and ǀlog 2FCǀ > 1.0. The GO, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and the protein-protein interaction (PPI) network analysis were performed with the detected DEGs.

RESULTS

The biological processes and signaling pathways involving common DEGs from airway epithelial datasets in COPD and tissue in peripheral atherosclerosis were identified. A total of 15 DEGs were identified, comprising 12 upregulated and 3 downregulated DEGs. The GO enrichment analysis demonstrated that the upregulated hub genes were mainly involved in the inflammatory response, reactive oxygen species metabolic process, cell adhesion, lipid metabolic process, regulation of angiogenesis, icosanoid biosynthetic process, and cellular response to a chemical stimulus. The KEGG pathway enrichment analysis demonstrated that the common pathways were Toll-like receptor signaling pathway, NF-kappa B signaling pathway, lipid and atherosclerosis, and cytokine-cytokine receptor interaction.

CONCLUSIONS

Biological processes and signaling pathways associated with the immune response may link the development and progression of COPD and atherosclerosis.

Plasma osteopontin levels and adverse clinical outcomes after ischemic stroke

BACKGROUND AND AIMS

Osteopontin is implicated in atherosclerosis, and its expression is upregulated in response to brain injury. The aim of this study was to prospectively investigate the associations between plasma osteopontin levels and adverse clinical outcomes in ischemic stroke patients.

METHODS

We measured baseline plasma osteopontin levels in 3545 ischemic stroke patients from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS). The primary outcome was the composite outcome of death and major disability (modified Rankin scale score ≥3) at 1 year after ischemic stroke, and secondary outcomes included major disability, death, and the composite outcome of death and vascular events.

RESULTS

During 1 year of follow-up, patients in the fourth quartile of plasma osteopontin had the highest risks of primary outcome, major disability, death, and the composite outcome of death and vascular events. After multivariate adjustment, the odds ratios or hazard ratios (95 % confidence intervals) associated with each standard deviation increase in log-transformed osteopontin were 1.20 (1.09-1.33) for primary outcome, 1.11 (1.00-1.23) for major disability, 1.29 (1.10-1.52) for death, and 1.15 (1.01-1.30) for the composite outcome of death and vascular events. The addition of plasma osteopontin to conventional risk factors significantly improved the risk reclassification for the primary outcome (net reclassification improvement: 16.91%, p < 0.001; integrated discrimination improvement: 0.43%, p = 0.002).

CONCLUSIONS

Elevated plasma osteopontin levels at baseline were associated with increased risks of adverse clinical outcomes at 1 year after ischemic stroke, suggesting that osteopontin is a promising prognostic biomarker for ischemic stroke.

Osteopontin in Cardiovascular Diseases

Unprecedented advances in secondary prevention have greatly improved the prognosis of cardiovascular diseases (CVDs); however, CVDs remain a leading cause of death globally. These findings suggest the need to reconsider cardiovascular risk and optimal medical therapy. Numerous studies have shown that inflammation, pro-thrombotic factors, and gene mutations are focused not only on cardiovascular residual risk but also as the next therapeutic target for CVDs. Furthermore, recent clinical trials, such as the Canakinumab Anti-inflammatory Thrombosis Outcomes Study trial, showed the possibility of anti-inflammatory therapy for patients with CVDs. Osteopontin (OPN) is a matricellular protein that mediates diverse biological functions and is involved in a number of pathological states in CVDs. OPN has a two-faced phenotype that is dependent on the pathological state. Acute increases in OPN have protective roles, including wound healing, neovascularization, and amelioration of vascular calcification. By contrast, chronic increases in OPN predict poor prognosis of a major adverse cardiovascular event independent of conventional cardiovascular risk factors. Thus, OPN can be a therapeutic target for CVDs but is not clinically available. In this review, we discuss the role of OPN in the development of CVDs and its potential as a therapeutic target.

Histopathological study of JNK in venous wall of patients with chronic venous insufficiency related to osteogenesis process

Chronic venous insufficiency (CVI) is one of the most common vascular pathologies worldwide. One of the risk factors for the development of CVI is aging, which is why it is related to senile changes. The main trigger of the changes that occur in the venous walls in CVI is blood flow reflux, which produces increased hydrostatic pressure, leading to valve incompetence. The cellular response is one of the fundamental processes in vascular diseases, causing the activation of cell signalling pathways such as c-Jun N-terminal kinase (JNK). Metabolic changes and calcifications occur in vascular pathology as a result of pathophysiological processes. The aim of this study was to determine the expression of JNK in venous disease and its relationship with the role played by the molecules involved in the osteogenic processes in venous tissue calcification. This was a cross-sectional study that analyzed the greater saphenous vein wall in 110 patients with (R) and without venous reflux (NR), classified according to age. Histopathological techniques were used and protein expression was analysed using immunohistochemistry techniques for JNK and markers of osteogenesis (RUNX2, osteocalcin (OCN), osteopontin (OPN)). Significantly increased JNK, RUNX2, OCN, OPN and pigment epithelium-derived factor (PEDF) protein expression and the presence of osseous metaplasia and amorphous calcification were observed in younger patients (<50 years) with venous reflux. This study shows for the first time the existence of an osteogenesis process related to the expression of JNK in the venous wall.

Glucose-Dependent Insulinotropic Peptide in the High-Normal Range Is Associated With Increased Carotid Intima-Media Thickness

OBJECTIVE

While existing evidence supports beneficial cardiovascular effects of glucagon-like peptide 1 (GLP-1), emerging studies suggest that glucose-dependent insulinotropic peptide (GIP) and/or signaling via the GIP receptor may have untoward cardiovascular effects. Indeed, recent studies show that fasting physiological GIP levels are associated with total mortality and cardiovascular mortality, and it was suggested that GIP plays a role in pathogenesis of coronary artery disease. We investigated the associations between fasting and postchallenge GIP and GLP-1 concentrations and subclinical atherosclerosis as measured by mean intima-media thickness in the common carotid artery (IMT_meanCCA) and maximal intima-media thickness in the carotid bifurcation (IMT_maxBulb).

RESEARCH DESIGN AND METHODS

Participants at reexamination within the Malmö Diet and Cancer-Cardiovascular Cohort study (n = 3,734, mean age 72.5 years, 59.3% women, 10.8% subjects with diabetes, fasting GIP available for 3,342 subjects, fasting GLP-1 available for 3,299 subjects) underwent oral glucose tolerance testing and carotid ultrasound.

RESULTS

In linear regression analyses, each 1-SD increment of fasting GIP was associated with increased (per mm) IMT_meanCCA (β = 0.010, P = 0.010) and IMT_maxBulb (β = 0.014; P = 0.040) in models adjusted for known risk factors and glucose metabolism. In contrast, each 1-SD increment of fasting GLP-1 was associated with decreased IMT_maxBulb (per mm, β = -0.016, P = 0.014). These associations remained significant when subjects with diabetes were excluded from analyses.

CONCLUSIONS

In a Swedish elderly population, physiologically elevated levels of fasting GIP are associated with increased IMT_meanCCA, while GLP-1 is associated with decreased IMT_maxBulb, further emphasizing diverging cardiovascular effects of these two incretin hormones.

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

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

Osteopontin in Vascular Disease

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

Osteoprotegerin and osteopontin levels, but not gene polymorphisms, predict mortality in cardiovascular diseases

Aim: This study aims to investigate whether osteoprotegerin (OPG) or osteopontin (OPN) single nucleotide polymorphisms (SNPs) will predict survival. Materials & methods: This study enrolled 617 participants undergoing health examination, 536 coronary artery disease (CAD) patients and 86 peripheral artery disease (PAD) patients. Genotypes of OPG SNP rs2073618 and OPN SNP rs11730582 were determined. OPG and OPN levels were measured. Results: In both CAD and PAD populations, high OPG and OPN levels were strong predictors of all-cause death. The OPG rs2073618 CC genotype and the OPN rs11730582 TT genotype did not predict mortality. Conclusion: High OPG and high OPN levels, but not OPG rs2073618 CC genotype or OPN rs11730582 TT genotype, were strong predictors of mortality in both CAD and PAD patients.

Osteopontin isoforms differentially promote arteriogenesis in response to ischemia via macrophage accumulation and survival

Osteopontin (OPN) is critical for ischemia-induced neovascularization. Unlike rodents, humans express three OPN isoforms (a, b, and c); however, the roles of these isoforms in post-ischemic neovascularization and cell migration remain undefined. Our objective was to determine if OPN isoforms differentially affect post-ischemic neovascularization and to elucidate the mechanisms underlying these differences. To investigate if human OPN isoforms exert divergent effects on post-ischemic neovascularization, we utilized OPN^-/- mice and a loss-of-function/gain-of-function approach in vivo and in vitro. In this study OPN^-/- mice underwent hindlimb ischemia surgery and 1.5 × 10⁶ lentivirus particles were administered intramuscularly to overexpress OPNa, OPNb, or OPNc. OPNa and OPNc significantly improved limb perfusion 30.4% ± 0.8 and 70.9% ± 6.3, respectively, and this translated to improved functional limb use, as measured by voluntary running wheel utilization. OPNa- and OPNc-treated animals exhibited significant increases in arteriogenesis, defined here as the remodeling of existing arterioles into larger conductance arteries. Macrophages play a prominent role in the arteriogenesis process and OPNa- and OPNc-treated animals showed significant increases in macrophage accumulation in vivo. In vitro, OPN isoforms did not affect macrophage polarization, whereas all three isoforms increased macrophage survival and decreased macrophage apoptosis. However, OPN isoforms exert differential effects on macrophage migration, where OPNa and OPNc significantly increased macrophage migration, with OPNc serving as the most potent isoform. In conclusion, human OPN isoforms exert divergent effects on neovascularization through differential effects on arteriogenesis and macrophage accumulation in vivo and on macrophage migration and survival, but not polarization, in vitro. Altogether, these data support that human OPN isoforms may represent novel therapeutic targets to improve neovascualrization and preserve tissue function in patients with obstructive artery diseases.

Serum high mobility group box-1 and osteoprotegerin levels are associated with peripheral arterial disease and critical limb ischemia in type 2 diabetic subjects

BACKGROUND

High mobility group box-1 (HMGB-1) is a nuclear protein also acting as inflammatory mediator, whilst osteoprotegerin (OPG), member of tumor necrosis factor receptor superfamily, is indicated as marker of vascular calcification. Peripheral artery disease (PAD) and type 2 diabetes (T2D) are clinical conditions characterized by elevated serum inflammatory markers and vascular calcification enhancement. The aim of this study was to investigate the potential role of HMGB-1, OPG and several inflammatory mediators such as C-reactive protein (HsCRP), tumor necrosis factor-alpha and interleukin-6 (IL-6) on the presence and severity of peripheral artery disease in patients with T2D.

METHODS

In this retrospective observational study, we have analyzed HMGB-1, OPG and inflammatory cytokines serum levels in 1393 type 2 diabetic patients with PAD and without PAD (WPAD).

RESULTS

HMGB-1 (7.89 ± 15.23 ng/mL), OPG (6.54 ± 7.76 pmol/L), HsCRP (15.6 ± 14.4 mg/L) and IL-6 (56.1 ± 28.6 pg/mL) serum levels were significantly higher in patients with PAD than in those WPAD (3.02 ± 8.12 ng/mL, P ˂ 0.001; 2.98 ± 2.01 pmol/L, P < 0.001; 7.05 ± 4.4 mg/L, P < 0.001; 37.5 ± 20.2 pg/mL, P < 0.001 respectively). Moreover HMGB-1 (P < 0.001), OPG (P < 0.001), HsCRP (P < 0.001) and IL-6 (P < 0.001) serum levels were positively correlated with clinical severity of PAD. HMGB-1 (adjusted OR 12.32; 95% CI 3.56-23.54, P = 0.023) and OPG (adjusted OR 3.53; 95% CI 1.54-6.15, P = 0.019) resulted independent determinants of PAD in patients with T2D after adjusting for the conventional cardiovascular risk factor and established inflammatory mediators.

CONCLUSIONS

In T2D patients HMGB-1 and OPG serum levels are higher in patients affected by PAD and independently associated with its occurrence and clinical severity.

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 circulating levels correlate with renal involvement in systemic lupus erythematosus and are lower in ACE inhibitor-treated patients

Elevated serum levels of osteopontin have been associated with cardiovascular disease, diabetic nephropathy, and autoimmune disease activity. Aim of the study was to investigate the relationship between osteopontin serum levels and renal damage in a population of patients with systemic lupus erythematosus (SLE). Osteopontin serum levels were analyzed in 101 SLE patients and compared to those of 115 healthy controls. Associations between osteopontin levels and renal involvement, disease activity and damage index, biochemical parameters, and therapy were assessed. Overall osteopontin serum levels were higher in SLE patients (median, 17.93 ng/mL; interquartile range, 8.13-35.07 ng/mL) than in healthy controls (median, 5.62 ng/mL; interquartile range, 2.61-13.83 ng/mL). Univariate logistic analysis among cases showed that high osteopontin levels (higher vs medium-lower tertile) were associated with renal involvement (p = 0.012), renal function (p = 0.007), proteinuria (p = 0.011), anemia (p < 0.001), and SLICC/ACR Damage Index (p < 0.001). Multivariate analysis showed an independent association between high osteopontin serum levels (higher vs medium-lower tertile) and chronic kidney disease (OR = 4.89; 95 % CI, 1.24-19.24; p = 0.008), proteinuria (OR = 4.56; 95 % CI, 1.15-18.04; p = 0.027), anemia (OR = 4.66; 95 % CI, 1.25-17.43; p = 0.008), and use of renin-angiontensin system antagonists (OR = 0.234; 95 % CI, 0.06-0.98; p = 0.047). This study shows that elevated osteopontin serum levels significantly correlate with renal involvement and anemia in SLE. Moreover, it suggests that renin-angiontensin system antagonists decrease osteopontin levels-this effect is consistent with the inhibitory effect of these drugs on osteopontin renal expression, detected in animal models by other authors, and may provide a new rationale for their employment.

Osteoprotegerin as a marker of atherosclerosis: a systematic update

OBJECTIVE

Osteoprotegerin (OPG) may be involved in development of atherosclerosis. To evaluate plasma concentrations of OPG in individuals with stable coronary artery disease (CAD), acute coronary syndrome (ACS), peripheral artery disease (PAD), and cerebrovascular disease (CBVD) a systematic literature review was performed.

DESIGN AND METHODS

Studies investigating OPG concentrations in stable CAD, ACS, PAD, and CBVD were extracted from PubMed and the Cochrane Library, retrieving 280 articles. Nonrelevant articles were excluded and after thorough evaluation, and only 14 studies with clearly defined cohorts qualified for this review.

RESULTS

In 11 studies, OPG concentrations were elevated. Severity of atherosclerosis was significantly associated with higher OPG concentrations compared to healthy controls. No association between PAD and OPG concentrations was observed.

CONCLUSION

OPG concentrations are associated with the presence and severity of stable CAD, ACS, and CBVD. Larger studies are needed to reach conclusions concerning OPG concentrations in PAD. Studies addressing a putative role for OPG in suspected CAD and CBVD are warranted.