Osteopontin is an endogenous modulator of the constitutively activated phenotype of pulmonary adventitial fibroblasts in hypoxic pulmonary hypertension

Increased cell proliferation and migration, of several cell types are key components of vascular remodeling observed in pulmonary hypertension (PH). Our previous data demonstrate that adventitial fibroblasts isolated from pulmonary arteries of chronically hypoxic hypertensive calves (termed PH-Fibs) exhibit a "constitutively activated" phenotype characterized by high proliferative and migratory potential. Osteopontin (OPN) has been shown to promote several cellular activities including growth and migration in cancer cells. We thus tested the hypothesis that elevated OPN expression confers the "activated" highly proproliferative and promigratory/invasive phenotype of PH-Fibs. Our results demonstrate that, both in vivo and ex vivo, PH-Fibs exhibited increased expression of OPN, as well as its cognate receptors, α(V)β(3) and CD44, compared with control fibroblasts (CO-Fibs). Augmented OPN expression in PH-Fibs corresponded to their high proliferative, migratory, and invasive properties and constitutive activation of ERK1/2 and AKT signaling. OPN silencing via small interfering RNA or sequestering OPN production by specific antibodies led to decreased proliferation, migration, invasion, and attenuated ERK1/2, AKT phosphorylation in PH-Fibs. Furthermore, increasing OPN levels in CO-Fibs via recombinant OPN resulted in significant increases in their proliferative, migratory, and invasive capabilities to the levels resembling those of PH-Fibs. Thus our data suggest OPN as an essential contributor to the activated (highly proliferative, migratory, and proinvasive) phenotype of pulmonary adventitial fibroblasts in hypoxic PH.

Novel cardiac-specific biomarkers and the cardiovascular continuum

The concept of the cardiovascular continuum, introduced during the early 1990s, created a holistic view of the chain of events connecting cardiovascular-related risk factors with the progressive development of pathological-related tissue remodelling and ultimately, heart failure and death. Understanding of the tissue-specific changes, and new technologies developed over the last 25-30 years, enabled tissue remodelling events to be monitored in vivo and cardiovascular disease to be diagnosed more reliably than before. The tangible product of this evolution was the introduction of a number of biochemical markers such as troponin I and T, which are now commonly used in clinics to measure myocardial damage. However, biomarkers that can detect specific earlier stages of the cardiovascular continuum have yet to be generated and utilised. The majority of the existing markers are useful only in the end stages of the disease where few successful intervention options exist. Since a large number of patients experience a transient underlying developing pathology long before the signs or symptoms of cardiovascular disease become apparent, the requirement for new markers that can describe the early tissue-specific, matrix remodelling process which ultimately leads to disease is evident. This review highlights the importance of relating cardiac biochemical markers with specific time points along the cardiovascular continuum, especially during the early transient phase of pathology progression where none of the existing markers aid diagnosis.

Markers of extracellular matrix turnover and the development of right ventricular failure after ventricular assist device implantation in patients with advanced heart failure

BACKGROUND

Cardiac extracellular matrix (ECM) is a dynamic and metabolically active collagenous network that responds to mechanical strain. The association between ECM turnover and right ventricular failure (RVF) development after left ventricular assist device (LVAD) implantation in patients with advanced heart failure (HF) was investigated.

METHODS

Circulating levels of osteopontin, metalloproteinases (MMP)-2 and MPP-9, and tissue inhibitor of MMP (TIMP)-1 and TIMP-4 were measured in 61 patients at LVAD implantation and explantation and in 10 control subjects. RVF was defined as the need for RVAD, nitric oxide inhalation > 48 hours and/or inotropic support > 14 days.

RESULTS

All ECM markers were elevated in patients with HF compared with controls (all p < 0.05). RVF developed in 23 patients (37.7%) on LVAD support. All ECM markers decreased on LVAD support in patients without RVF (all p < 0.05), but serum MMP-2, TIMP-1, TIMP-4, and osteopontin remained elevated in RVF patients. Multivariate analysis identified that right ventricular stroke work index (RVSWI), circulating B-type natriuretic peptide, and osteopontin were associated with RVF (all p < 0.05). Osteopontin correlated inversely with RVSWI (r = -0.44, p < 0.001). Osteopontin levels > 260 ng/ml discriminate patients who develop RVF from those without RVF (sensitivity, 83%; specificity, 82%).

CONCLUSIONS

Marked elevation of osteopontin levels before LVAD placement is associated with RVF development. Persistent elevation of circulating ECM markers after LVAD implantation characterizes patients who develop RVF. These novel biomarkers would have a potential role in the prediction of RVF development in patients undergoing LVAD implantation.

Prognosis of ampullary cancer based on immunohistochemical type and expression of osteopontin

Background

Ampullary cancer (AC) was classified as pancreatobiliary, intestinal, or other subtype based on the expression of cytokeratin 7 (CK7) and cytokeratin 20 (CK20). We aimed to explore the association of AC subtype with patient prognosis.

Methods

The relationship of AC subtype and expression of Osteopontin (OPN) with the prognosis of 120 AC patients after pancreaticoduodenectomy was investigated.

Results

The patients had pancreatobiliary (CK7⁺/CK20^-, n = 24, 20%), intestinal (CK7^-/CK20⁺, n = 29, 24.2%) or other (CK7⁺/CK20⁺ or CK7^-/CK20^-, n = 67, 55.8%) subtypes of AC, and their median survival times were 23 ± 4.2, 38 ± 2.8 and 64 ± 16.8 months, respectively. The survival times of 64 OPN^- patients (53.3%) and 56 OPN⁺ patients (46.7%) were 69 ± 18.4 and 36 ± 1.3 months, respectively. There was no significant effect of AC subtype on survival of OPN^- patients. For OPN⁺ patients, those with pancreatobiliary AC had a shorter survival time (22 ± 6.6 months) than those with intestinal AC (37 ± 1.4 months, p = 0.041), and other AC subtype (36 ± 0.9 months, p = 0.010); intestinal and other AC subtypes had similar survival times.

Conclusions

The prognosis of AC patients can be estimated based on immunohistochemical classification and OPN status.

Soluble guanylate cyclase stimulation prevents fibrotic tissue remodeling and improves survival in salt-sensitive Dahl rats

BACKGROUND

A direct pharmacological stimulation of soluble guanylate cyclase (sGC) is an emerging therapeutic approach to the management of various cardiovascular disorders associated with endothelial dysfunction. Novel sGC stimulators, including riociguat (BAY 63-2521), have a dual mode of action: They sensitize sGC to endogenously produced nitric oxide (NO) and also directly stimulate sGC independently of NO. Little is known about their effects on tissue remodeling and degeneration and survival in experimental malignant hypertension.

METHODS AND RESULTS

Mortality, hemodynamics and biomarkers of tissue remodeling and degeneration were assessed in Dahl salt-sensitive rats maintained on a high salt diet and treated with riociguat (3 or 10 mg/kg/d) for 14 weeks. Riociguat markedly attenuated systemic hypertension, improved systolic heart function and increased survival from 33% to 85%. Histological examination of the heart and kidneys revealed that riociguat significantly ameliorated fibrotic tissue remodeling and degeneration. Correspondingly, mRNA expression of the pro-fibrotic biomarkers osteopontin (OPN), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and plasminogen activator inhibitor-1 (PAI-1) in the myocardium and the renal cortex was attenuated by riociguat. In addition, riociguat reduced plasma and urinary levels of OPN, TIMP-1, and PAI-1.

CONCLUSIONS

Stimulation of sGC by riociguat markedly improves survival and attenuates systemic hypertension and systolic dysfunction, as well as fibrotic tissue remodeling in the myocardium and the renal cortex in a rodent model of pressure and volume overload. These findings suggest a therapeutic potential of sGC stimulators in diseases associated with impaired cardiovascular and renal functions.