Pacing-induced regional differences in adenosine receptors mRNA expression in a swine model of dilated cardiomyopathy

Osteopontin in hepatocellular carcinoma: A possible biomarker for diagnosis and follow-up

Recently osteopontin (OPN), a protein of the extracellular matrix, has generated in hepatocellular carcinoma (HCC) a significant interest as a prognostic factor. Aim of this study was to confirm, in liver tissues of subjects with HCV-positive HCC undergoing liver transplantation (RL, n=10) and of donors (DL, n=14), the increase of OPN plasma and tissue concentration, the OPN splicing isoforms expression profiling together with those of thrombin, and to evaluate a possible association between OPN measurements. Their association with Notch-1, IV-Collagen-7s domain, IL-6 and TNF-α were also evaluated. Real-Time PCR experiments and immunometric assay were performed. mRNA expression resulted higher in RL than in DL for all analyzed genes and several correlations were found between them. The more relevant association were between OPN-a and OPN-b (p<0.0001), between thrombin and OPN-a (p=0.007), between 7s-collagen and OPN isoforms (p<0.05) and between Notch-1 with OPN-c (p=0.004). Both OPN plasma and liver tissue extract concentrations were assessed confirming the trend observed at the mRNA level. An important association was found between OPN plasma and protein (p<0.0001, r=0.96) even splitting patients in DL (p<0.0001, r=0.93) and RL (p<0.0001, r=0.96). A reduction of OPN plasma levels was found at 6months after transplantation. Considering MELD score as liver disease severity, the mRNA expression of our markers as well as of OPN plasma and tissue concentrations resulted increased as a function of clinical severity. Our results might be considered a useful starting point to validate OPN as a prognostic and diagnostic marker of HCC.

New cardiac expression of two adenosine-2A receptor isoforms in dysfunctioning minipigs

PURPOSE

Eight A_2AR variants are reported in humans while no A_2AR isoforms in pigs. The aim of this study was to evaluate potential isoforms presence in cardiac pig tissue to better define possible involvement of A_2AR in the cardiovascular pathophysiology.

MATERIALS AND METHODS

In adult male minipigs (n = 4) left ventricular dysfunction (LVD) was induced by pacing at 200 bpm in the right ventricular (RV) apex. In these animals and in sham operated pigs (C-SHAM, n = 4) cardiac tissue was collected from LV-septal wall (LV-SW)-close to pacing site-and from lateral (opposite) site (LV-OSW). A_2AR specific primers, derived from Sus scrofa AY772412 sequence, were used for Real-Time PCR. The DNA was sequenced using the Sanger method. Histological analysis was also performed.

RESULTS

In LV-SW of LVD minipigs the A_2AR melting curves were characterized by a sharp peak between 87 and 91 °C (short isoform, 1-94 bp) on the right of the principal peak corresponding to a long A_2AR isoform (GenBank: JQ229674.1) 1-213 bp. As for C-SHAM only one peak was observed in LV-OSW region of LVD animals. The short isoform had an alternative promoter region and a specific translated protein. Histology showed in LVD-LV-SW prominent Purkinje cells compared to LV-OSW and C-SHAM. No difference in A_2AR expression was observed between LVD animals and C-SHAM although a slight decrease was observed in LVD-LV-OSW.

CONCLUSIONS

The presence of two different isoforms in the myocardium close to the insertion of pacing is suggestive of a differential state-specific expression of A_2AR in cardiac tissue.

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.

Cardiac purinergic signalling in health and disease

This review is a historical account about purinergic signalling in the heart, for readers to see how ideas and understanding have changed as new experimental results were published. Initially, the focus is on the nervous control of the heart by ATP as a cotransmitter in sympathetic, parasympathetic, and sensory nerves, as well as in intracardiac neurons. Control of the heart by centers in the brain and vagal cardiovascular reflexes involving purines are also discussed. The actions of adenine nucleotides and nucleosides on cardiomyocytes, atrioventricular and sinoatrial nodes, cardiac fibroblasts, and coronary blood vessels are described. Cardiac release and degradation of ATP are also described. Finally, the involvement of purinergic signalling and its therapeutic potential in cardiac pathophysiology is reviewed, including acute and chronic heart failure, ischemia, infarction, arrhythmias, cardiomyopathy, syncope, hypertrophy, coronary artery disease, angina, diabetic cardiomyopathy, as well as heart transplantation and coronary bypass grafts.

Acute decrease of cerebral oxygen saturation during rapid ventricular and supraventricular rhythm: a pilot study

BACKGROUND

Monitoring of cerebral tissue oxygen saturation (SctO2 ) reflects cerebral microcirculation. We sought to characterize the decrease in SctO2 during supraventricular tachycardia (SVT) and ventricular tachycardia (VT) in adults.

METHODS

Twenty patients (mean age: 46.3 ± 18.1 years, 40% men) were included. Rapid atrial and ventricular pacing (200/min) was used as a model for VT and SVT. Near-infrared spectroscopy (NIRS) was used to measure SctO2 .

RESULTS

Atrial stimulation decreased right (P = 0.014) and left (P = 0.019) hemispheric SctO2 compared to baseline. Ventricular stimulation also decreased right (P < 0.001) and left (P < 0.001) hemispheric SctO2 . A negative correlation between age and minimal value under stimulation was found for atrial (right SctO2 r = -0.641, P = 0.034; left SctO2 r = -0.694, P = 0.018) and ventricular pacing (right SctO2 r = -0.564, P = 0.01; left SctO2 r = -0.604, P = 0.005). A positive correlation was found between left ventricular ejection fraction (LVEF) and minimal value under ventricular stimulation (right SctO2 r = 0.567, P = 0.009; left SctO2 r = 0.471, P = 0.036).

CONCLUSION

Cerebral perfusion decreased during simulated SVT and VT and is influenced by age and LVEF. Clinicians can consider NIRS monitoring in patients during ablation procedures and in critical care. NIRS may especially be appropriate for the elderly and for patients with impaired LVEF.

The role of the adenosinergic system in lung fibrosis

Adenosine (ADO) is a retaliatory metabolite that is expressed in conditions of injury or stress. During these conditions ATP is released at the extracellular level and is metabolized to adenosine. For this reason, adenosine is defined as a "danger signal" for cells and organs, in addition to its important role as homeostatic regulator. Its physiological functions are mediated through interaction with four specific transmembrane receptors called ADORA1, ADORA2A, ADORA2B and ADORA3. In the lungs of mice and humans all four adenosine receptors are expressed with different roles, having pro- and anti-inflammatory roles, determining bronchoconstriction and regulating lung inflammation and airway remodeling. Adenosine receptors can also promote differentiation of lung fibroblasts into myofibroblasts, typical of the fibrotic event. This last function suggests a potential involvement of adenosine in the fibrotic lung disease processes, which are characterized by different degrees of inflammation and fibrosis. Idiopathic pulmonary fibrosis (IPF) is the pathology with the highest degree of fibrosis and is of unknown etiology and burdened by lack of effective treatments in humans.

Transcriptomic profiling of the four adenosine receptors in human leukocytes of heart failure patients

In this study the transcriptomic profiling of adenosine receptors (ARs) in human leukocytes of heart failure (HF) patients as a function of clinical severity, assessing the possible changes with respect to healthy subjects (C), was evaluated. Total RNA was extracted from leukocytes of C (n = 8) and of HF patients (NYHA I-II n = 9; NYHA III-IV n = 14) with a PAXgene Blood RNA Kit. An increase as a function of clinical severity was observed in each AR (A₁R: C = 0.02 ± 0.009, NYHA I-II = 0.21 ± 0.09, NYHA III-IV = 3.6 ± 1.3, P = 0.03  C versus NYHA III-IV, P = 0.02 NYHA I-II versus NYHA III-IV; A_2aR: C = 0.2 ± 0.05, NYHA I-II = 0.19 ± 0.04, NYHA III-IV = 1.32 ± 0.33, P = 0.005  C versus NYHA III-IV, P = 0.003 NYHA I-II versus NYHA III-IV; A_2bR: C = 1.78 ± 0.36, NYHA I-II = 1.35 ± 0.29, NYHA III-IV = 4.07 ± 1.21, P = 0.03: NYHA I-II versus NYHA III-IV; A₃R: C = 0.76 ± 0.21, NYHA I-II = 0.94 ± 0.19, NYHA III-IV = 3.14 ± 0.77, P = 0.01  C versus NYHA III-IV and NYHA I-II versus NYHA III-IV, resp.). The mRNA expression of the ectonucleoside triphosphate diphosphohydrolase (CD39) and the ecto-5′-nucleotidase (CD73) were also evaluated. They resulted up-regulated. These findings show that components of adenosine metabolism and signalling are altered to promote adenosine production and signalling in HF patients. Thus, HF may benefit from adenosine-based drug therapy after confirmation by clinical trials.