Mechanisms of remodelling: a question of life (stem cell production) and death (myocyte apoptosis)

Utility of dobutamine stress echocardiography in aortic valve regurgitation and reduced left ventricular function

OBJECTIVE

Predictors for post-operative reverse remodeling in patients with severe aortic regurgitation (AR) and reduced left ventricular ejection fraction (LVEF) are unknown. We performed low-dose dobutamine stress echocardiography (DSE) in patients with severe AR and reduced LVEF to evaluate the relationship between contractile reserve (CR) and reverse remodeling after surgery.

METHODS

In 31 patients with chronic severe AR and reduced LVEF (LVEF < 50%), we performed pre-operative DSE, assessed CR, and examined whether changes in preoperative DSE were associated with improvement of post-operative LVEF after aortic valve surgery.

RESULTS

The pre-operative echocardiographic findings were as follows: left ventricular (LV) end-diastolic dimension: 67 ± 10 mm, LV end-systolic dimension: 52 ± 13 mm, and LVEF: 42 ± 8%. All patients underwent aortic valve surgery. Patients with pre-operative LVEF of ≥45% exhibited a significant increase in LVEF; however, patients with pre-operative LVEF of <45% showed no significant change. When we examined the results of DSE performed in patients with pre-operative LVEF of <45%, ΔLVEF of ≥6% (with CR) during DSE was related to an improvement in post-operative LVEF; ΔLVEF of ≥6% during DSE predicted an improvement in post-operative LVEF, with sensitivity 100%; specificity 78%; and area under curve (AUC) .92.

CONCLUSIONS

DSE might be a helpful tool for predicting post-operative reverse remodeling in patients with severe AR and moderately reduced LVEF.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

Current views on anthracycline cardiotoxicity

Anthracyclines are well established and effective anticancer agents used to treat a variety of adult and pediatric cancers. Unfortunately, these drugs are also among the commonest chemotherapeutic agents that have been recognized to cause cardiotoxicity. In the last years, several experimental and clinical investigations provided new information and perspectives on anthracycline-related cardiotoxicity. In particular, molecular mechanisms of cardiotoxicity have been better elucidated, early diagnosis has improved through the use of advanced noninvasive cardiac imaging techniques, and emerging data indicate a genetic predisposition to develop anthracycline-related cardiotoxicity. In this article, we review established and new knowledge about anthracycline cardiotoxicity, with special focus on recent advances in cardiotoxicity diagnosis and genetic profiling.

The exon junction complex senses energetic stress and regulates contractility and cell architecture in cardiac myocytes

The exon junction complex (EJC) is the main mechanism by which cells select specific mRNAs for translation into protein. We hypothesized that the EJC is involved in the regulation of gene expression during the stress response in cardiac myocytes, with implications for the failing heart. In cultured rat neonatal myocytes, we examined the cellular distribution of two EJC components eukaryotic translation initiation factor 4A isoform 3 (eIF4A3) and mago nashi homologue (Mago) in response to metabolic stress. There was significant relocalization of eIF4A3 and Mago from the nucleus to cytoplasm following 18 h of hypoxia. Treating myocytes with 50 mM NaN₃ for 4 h to mimic the metabolic stress induced by hypoxia also resulted in significant relocalization of eIF4A3 and Mago to the cytoplasm. To examine whether the effects of metabolic stress on the EJC proteins were dependent on the metabolic sensor AMP kinase (AMPK), we treated myocytes with 1 μM dorsomorphin (DM) in combination with NaN₃ DM augmented the translocation of Mago and eIF4A3 from the nucleus to the cytoplasm. Knockdown of eIF4A3 resulted in cessation of cell contractility 96 h post-treatment and a significant reduction in the number of intact sarcomeres. Cell area was significantly reduced by both hypoxia and eIF4A3 knockdown, whilst eIF4A3 knockdown also significantly reduced nuclear size. The reduction in nuclear size is unlikely to be related to apoptosis as it was reversed in combination with hypoxia. These data suggest for the first time that eIF4A3 and potentially other EJC members play an important role in the myocyte stress response, cell contractility and morphology.

Frequency of early remodeling of left ventricle and its comparison between patients with stroke volume ≥97 Ml versus patients with stroke volume <97 Ml after aortic valve replacement for severe aortic regurgitation

Objectives:

To evaluate the frequency of early remodeling in patients of severe aortic regurgitation after aortic valve replacement and to see the incidence of early remodeling in patients with stroke volume >97 ml versus < 97 ml before aortic valve replacement.

Method:

This was a prospective comparative study conducted from August 2013 to December 2014 in a tertiary care hospital. Fifty seven (57) patients of isolated chronic aortic regurgitation were included in this study. SPSS v23 was used for data analysis. Independent sample t-test was used for analysis of continuous variables and chi-square test for qualitative variables.

Results:

Out of fifty seven patients, early remodeling occurred in 34 (59.64%) patients after surgery. The mean pre-operative stroke volume of patient in whom remodeling occurred was 110.3+9.66 ml while mean pre-operative stroke volume of patients who did not undergo remodeling was 86.65+7.63 ml. There were 28 (82.4%) patients with stroke volume >97 ml in whom Remodeling occurred where as in patients with stroke volume <97 ml remodeling occurred only in 6 (17.6%) patients (p value 0.004). There was no in-hospital mortality.

Conclusion:

There is an association between stroke volume and early LV remodeling after Aortic valve replacement. Stroke volume >97 ml is a good predictor of early LV remodeling.

Sphingosine 1-phosphate elicits RhoA-dependent proliferation and MRTF-A mediated gene induction in CPCs

Although c-kit(+) cardiac progenitor cells (CPCs) are currently used in clinical trials there remain considerable gaps in our understanding of the molecular mechanisms underlying their proliferation and differentiation. G-protein coupled receptors (GPCRs) play an important role in regulating these processes in mammalian cell types thus we assessed GPCR mRNA expression in c-kit(+) cells isolated from adult mouse hearts. Our data provide the first comprehensive overview of the distribution of this fundamental class of cardiac receptors in CPCs and reveal notable distinctions from that of adult cardiomyocytes. We focused on GPCRs that couple to RhoA activation in particular those for sphingosine-1-phosphate (S1P). The S1P2 and S1P3 receptors are the most abundant S1P receptor subtypes in mouse and human CPCs while cardiomyocytes express predominantly S1P1 receptors. Treatment of CPCs with S1P, as with thrombin and serum, increased proliferation through a pathway requiring RhoA signaling, as evidenced by significant attenuation when Rho was inhibited by treatment with C3 toxin. Further analysis demonstrated that both S1P- and serum-induced proliferation are regulated through the S1P2 and S1P3 receptor subtypes which couple to Gα12/13 to elicit RhoA activation. The transcriptional co-activator MRTF-A was activated by S1P as assessed by its nuclear accumulation and induction of a RhoA/MRTF-A luciferase reporter. In addition S1P treatment increased expression of cardiac lineage markers Mef2C and GATA4 and the smooth muscle marker GATA6 through activation of MRTF-A. In conclusion, we delineate an S1P-regulated signaling pathway in CPCs that introduces the possibility of targeting S1P2/3 receptors, Gα12/13 or RhoA to influence the proliferation and commitment of c-kit(+) CPCs and improve the response of the myocardium following injury.

The role of lipotoxicity in smoke cardiomyopathy

Background/Aims

Experimental and clinical studies have shown the direct toxic effects of cigarette smoke (CS) on the myocardium, independent of vascular effects. However, the underlying mechanisms are not well known.

Methods

Wistar rats were allocated to control (C) and cigarette smoke (CS) groups. CS rats were exposed to cigarette smoke for 2 months.

Results

After that morphometric, functional and biochemical parameters were measured. The echocardiographic study showed enlargement of the left atria, increase in the left ventricular systolic volume and reduced systolic function. Within the cardiac metabolism, exposure to CS decreased beta hydroxy acyl coenzyme A dehydrogenases and citrate synthases and increased lactate dehydrogenases. Peroxisome proliferator-activated receptor alpha (PPARα) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) were expressed similarly in both groups. CS increased serum lipids and myocardial triacylglycerols (TGs). These data suggest that impairment in fatty acid oxidation and the accumulation of cardiac lipids characterize lipotoxicity. CS group exhibited increased oxidative stress and decreased antioxidant defense. Finally, the myocyte cross-sectional area and active Caspase 3 were increased in the CS group.

Conclusion

The cardiac remodeling that was observed in the CS exposure model may be explained by abnormalities in energy metabolism, including lipotoxicity and oxidative stress.

The Notch pathway: a novel target for myocardial remodelling therapy?

Pathological ventricle remodelling, which follows a cardiac insult, causes heart failure. Despite the existence of multiple pharmaceutical approaches, heart failure is one of the leading causes of death worldwide and there is an urgent need to explore new therapeutic avenues. The Notch pathway is an evolutionary conserved fundamental pathway that regulates cell fate during development as well as throughout postnatal life in self-renewing tissues. In the myocardium, Notch signalling is involved in the modulation of cardiomyocytes survival, cardiac stem cells differentiation, and angiogenesis which are factors known to determine the extent of pathological cardiac remodelling. Modulation of the Notch pathway could become a tool to limit ventricle remodelling and the associated inexorable deterioration of cardiac performance.

Xenon and isoflurane reduce left ventricular remodeling after myocardial infarction in the rat

BACKGROUND

Xenon and isoflurane are known to have cardioprotective properties. We tested the hypothesis that these anesthetics positively influence myocardial remodeling 28 days after experimental perioperative myocardial infarction and compared their effects.

METHODS

A total of 60 male Sprague-Dawley rats were subjected to 60 min of coronary artery occlusion and 120 min of reperfusion. Prior to ischemia, the animals were randomized for the different narcotic regimes (0.6 vol% isoflurane, 70 vol% xenon, or intraperitoneal injection of s-ketamine). Acute injury was quantified by echocardiography and troponin I. After 4 weeks, left ventricular function was assessed by conductance catheter to quantify hemodynamic compromise. Cardiac remodeling was characterized by quantification of dilatation, hypertrophy, fibrosis, capillary density, apoptosis, and expression of fetal genes (α/β myosin heavy chains, α-skeletal actin, periostin, and sarco/endoplasmic reticulum Ca2+-ATPase).

RESULTS

Whereas xenon and isoflurane impeded the acute effects of ischemia-reperfusion on hemodynamics and myocardial injury at a comparable level, differences were found after 4 weeks. Xenon in contrast to isoflurane or ketamine anesthetized animals demonstrated a lower remodeling index (0.7 ± 0.1 vs. 0.9 ± 0.3 and 1.0 ± 0.3g/ml), better ejection fraction (62 ± 9 vs. 49 ± 7 and 35 ± 6%), and reduced expression of β-myosin heavy chain and periostin. The effects on hypertrophy, fibrosis, capillary density, and apoptosis were comparable.

CONCLUSIONS

Compared to isoflurane and s-ketamine, xenon limited progressive adverse cardiac remodeling and contractile dysfunction 28 days after perioperative myocardial infarction.

Cardiomyocyte ATP production, metabolic flexibility, and survival require calcium flux through cardiac ryanodine receptors in vivo

Ca(2+) fluxes between adjacent organelles are thought to control many cellular processes, including metabolism and cell survival. In vitro evidence has been presented that constitutive Ca(2+) flux from intracellular stores into mitochondria is required for basal cellular metabolism, but these observations have not been made in vivo. We report that controlled in vivo depletion of cardiac RYR2, using a conditional gene knock-out strategy (cRyr2KO mice), is sufficient to reduce mitochondrial Ca(2+) and oxidative metabolism, and to establish a pseudohypoxic state with increased autophagy. Dramatic metabolic reprogramming was evident at the transcriptional level via Sirt1/Foxo1/Pgc1α, Atf3, and Klf15 gene networks. Ryr2 loss also induced a non-apoptotic form of programmed cell death associated with increased calpain-10 but not caspase-3 activation or endoplasmic reticulum stress. Remarkably, cRyr2KO mice rapidly exhibited many of the structural, metabolic, and molecular characteristics of heart failure at a time when RYR2 protein was reduced 50%, a similar degree to that which has been reported in heart failure. RYR2-mediated Ca(2+) fluxes are therefore proximal controllers of mitochondrial Ca(2+), ATP levels, and a cascade of transcription factors controlling metabolism and survival.

Caspase-3 activation and increased procollagen type I in irradiated hearts

The caspase-3-cleaved presence was evaluated in this study in the heart of irradiated rats, during the decline of ventricular function. Female Wistar rats were irradiated with a single dose of radiation (15 Gy) delivered directly to the heart and the molecular, histological and physiological evaluations were performed at thirteen months post-irradiation. The expressions of procollagen type I, TGF-ß1 and caspase-3-cleaved were analyzed using Western blotting. Cardiac structural and functional alterations were investigated by echocardiography and electron microscopy. In the irradiated group, the levels of procollagen type I, TGF-ß1 and caspase-3-cleaved are increased. Significant histological changes (degeneration of heart tissue and collagen deposition) and functional (reduced ejection fraction) were observed. Data suggest that the cardiac function decline after exposure to ionizing radiation is related, in part, to increased collagen and increased caspase-3-cleaved.

Treatment of Reperfused Ischemia with Adipose-Derived Stem Cells in a Preclinical Swine Model of Myocardial Infarction

The aim of the study was to determine the long-term effect of transplantation of adipose-derived stromal cells (ADSCs) in a preclinical model of ischemia/reperfusion (I/R). I/R was induced in 28 Goettingen minipigs by 120 min of coronary artery occlusion followed by reperfusion. Nine days later, surviving animals were allocated to receive transendocardial injection of a mean of 213.6 ± 41.78 million green fluorescent protein (GFP)-expressing ADSCs ( n = 7) or culture medium as control ( n = 9). Heart function, cell engraftment, and histological analysis were performed 3 months after transplantation. Transplantation of ADSCs induced a statistically significant long-lasting (3 months) improvement in cardiac function and geometry in comparison with control animals. Functional improvement was associated with an increase in angiogenesis and vasculogenesis and a positive effect on heart remodeling with a decrease in fibrosis and cardiac hypertrophy in animals treated with ADSCs. Despite the lack of cell engraftment after 3 months, ADSC transplantation induced changes in the ratio between MMP/TIMP. Our results indicate that transplantation of ADSCs, despite the lack of long-term significant cell engraftment, increases vessel density and prevents adverse remodeling in a clinically relevant model of myocardial infarction, strongly suggesting a paracrine-mediated effect. ADSCs thus constitute an attractive candidate for the treatment of myocardial infarction.

Association of pre-operative interleukin-6 levels with Interagency Registry for Mechanically Assisted Circulatory Support profiles and intensive care unit stay in left ventricular assist device patients

BACKGROUND

Inflammatory mechanisms are associated with worse prognosis in end-stage heart failure (ESHF) patients who require left ventricular assist device (LVAD) support. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles describe patient condition at pre-implant and outcome. This study assessed the relationship among inflammation patterns and INTERMACS profiles in LVAD recipients.

METHOD

Thirty ESHF patients undergoing LVAD implantation as bridge to transplant were enrolled. Blood and urine samples were collected pre-operatively and serially up to 2 weeks post-operatively for assessment of inflammatory markers (plasma levels of interleukin [IL]-6, IL-8, IL-10, and osteopontin, a cardiac inflammatory-remodeling marker; and the urine neopterin/creatinine ratio, a monocyte activation marker). Multiorgan function was evaluated by the total sequential organ failure assessment (tSOFA) score. Outcomes of interest were early survival, post-LVAD tSOFA score, and intensive care unit (ICU) length of stay.

RESULTS

Fifteen patients had INTERMACS profiles 1 or 2 (Group A), and 15 had profiles 3 or 4 (Group B). At pre-implant, only IL-6 levels and the IL-6/IL-10 ratio were higher in Group A vs B. After LVAD implantation, neopterin/creatinine ratio and IL-8 levels increased more in Group A vs B. Osteopontin levels increased significantly only in Group B. The tSOFA score at 2 weeks post-LVAD and ICU duration were related with pre-implant IL-6 levels.

CONCLUSIONS

The INTERMACS profiles reflect the severity of the pre-operative inflammatory activation and the post-implant inflammatory response, affecting post-operative tSOFA score and ICU stay. Therefore, inflammation may contribute to poor outcome in patients with severe INTERMACS profile.

Left-ventricular shape determines intramyocardial mechanical heterogeneity

Left-ventricular remodeling is considered to be an important mechanism of disease progression leading to mechanical dysfunction of the heart. However, the interaction between the physiological changes in the remodeling process and the associated mechanical dysfunction is still poorly understood. Clinically, it has been observed that the left ventricle often undergoes large shape changes, but the importance of left-ventricular shape as a contributing factor to alterations in mechanical function has not been clearly determined. Therefore, the interaction between left-ventricular shape and systolic mechanical function was examined in a computational finite-element study. Hereto, finite-element models were constructed with varying shapes, ranging from an elongated ellipsoid to a sphere. A realistic transmural gradient in fiber orientation was considered. The passive myocardium was described by an incompressible hyperelastic material law with transverse isotropic symmetry. Activation was governed by the eikonal-diffusion equation. Contraction was incorporated using a Hill model. For each shape, simulations were performed in which passive filling was followed by isovolumic contraction and ejection. It was found that the intramyocardial distributions of fiber stress, strain, and stroke work density were shape dependent. Ejection performance was reduced with increasing sphericity, which was regionally related to a reduction in the active fiber stress development, fiber shortening, and stroke work in the midwall and subepicardial region at the midheight level in the left-ventricular wall. Based on these results, we conclude that a significant interaction exists between left-ventricular shape and regional myofiber mechanics, but the importance for left-ventricular remodeling requires further investigation.

Myocardial remodeling: cellular and extracellular events and targets

The focus of this review is on translational studies utilizing large-animal models and clinical studies that provide fundamental insight into cellular and extracellular pathways contributing to post-myocardial infarction (MI) left ventricle (LV) remodeling. Specifically, both large-animal and clinical studies have examined the potential role of endogenous and exogenous stem cells to alter the course of LV remodeling. Interestingly, there have been alterations in LV remodeling with stem cell treatment despite a lack of long-term cell engraftment. The translation of the full potential of stem cell treatments to clinical studies has yet to be realized. The modulation of proteolytic pathways that contribute to the post-MI remodeling process has also been examined. On the basis of recent large-animal studies, there appears to be a relationship between stem cell treatment post-MI and the modification of proteolytic pathways, generating the hypothesis that stem cells leave an echo effect that moderates LV remodeling.

Adipose tissue-derived stem cells display a proangiogenic phenotype on 3D scaffolds

Ischemic heart disease is the leading cause of death worldwide. Recent studies suggest that adipose tissue-derived stem cells (ASCs) can be used as a potential source for cardiovascular tissue engineering due to their ability to differentiate along the cardiovascular lineage and to adopt a proangiogenic phenotype. To understand better ASCs' biology, we used a novel 3D culture device. ASCs' and b.END-3 endothelial cell proliferation, migration, and vessel morphogenesis were significantly enhanced compared to 2D culturing techniques. ASCs were isolated from inguinal fat pads of 6-week-old GFP+/BLI+ mice. Early passage ASCs cells (P3-P4), PKH26-labeled murine b.END-3 cells or a co-culture of ASCs and b.END-3 cells were seeded at a density of 1 × 10(5) on three different surface configurations: (a) a 2D surface of tissue culture plastic, (b) Matrigel, and (c) a highly porous 3D scaffold fabricated from inert polystyrene. VEGF expression, cell proliferation, and tubulization, were assessed using optical microscopy, fluorescence microscopy, 3D confocal microscopy, and SEM imaging (n = 6). Increased VEGF levels were seen in conditioned media harvested from co-cultures of ASCs and b.END-3 on either Matrigel or a 3D matrix. Fluorescence, confocal, SEM, bioluminescence revealed improved cell, proliferation, and tubule formation for cells seeded on the 3D polystyrene matrix. Collectively, these data demonstrate that co-culturing ASCs with endothelial cells in a 3D matrix environment enable us to generate prevascularized tissue-engineered constructs. This can potentially help us to surpass the tissue thickness limitations faced by the tissue engineering community today.

Early development of hyponatremia implicates short- and long-term outcomes in ST-elevation acute myocardial infarction

BACKGROUND

Clinical importance of hyponatremia in ST-elevation acute myocardial infarction (STEMI) in the era of primary intervention has not been fully understood. The aim of this study was to investigate the impact of hyponatremia on outcomes in patients with STEMI and secondarily to investigate the contribution of arginine vasopressin (AVP) to hyponatremia in STEMI.

METHODS AND RESULTS

Hyponatremia was defined as a sodium concentration <136 mmol/L at 72h after hospitalization. First, the short-term (in-hospital mortality or congestive heart failure (CHF)) and long-term prognosis (cardiac death, re-admission for CHF) in STEMI patients was conducted. Second, the relationship between serum sodium level and plasma AVP was investigated. In hyponatremic patients the incidence of in-hospital heart failure was significantly greater (P=0.0018), long-term cardiac death was a higher trend (17.2% vs. 6.3%, P=0.19) and re-admission due to CHF was significantly more frequent (20.7% vs. 4.5%, P=0.0024). Plasma AVP level was higher in the hyponatremia group (4.5 vs. 2.7 pg/ml, P=0.003), and it had a negative correlation with serum sodium level (r=-0.28, P=0.02).

CONCLUSIONS

Hyponatremia was frequently found in the early phase of STEMI, and associated with heart failure in both short- and long-term outcomes. Non-osmotic secretion of AVP could be involved in hyponatremia in STEMI patients.

Osteo-progenitors in vascular calcification: a circulating cell theory

Vascular calcification has been associated with the incidence of cardiovascular events and thus there has been interest in better understanding its pathogenesis. Early theories considered vascular calcification to be a passive process which occurred as a non-specific response to tissue injury or necrosis. More recent theories propose vascular calcification results from loss of molecular inhibitors or via an active cell mediated process. The origin of the cells responsible for vascular calcification is controversial and may vary in different sites and patients. Calcification has been reported as result of apoptosis or death of vascular smooth muscle cells for example. One novel source of cells controlling vascular calcification is from the bone marrow. A circulating immature bone marrow derived population has been identified and a small subset of this bone marrow population has been reported to possess bone forming properties in vitro and hence termed osteo-progenitors. This article reviews evidence supporting the contribution of these naive bone marrow derived circulating osteo-progenitor cells in vascular calcification.

Circulating concentrations of stem-cell-mobilizing cytokines are associated with levels of osteoprogenitor cells and aortic calcification severity

BACKGROUND

To investigate the association between aortic calcification, concentrations of stem-cell-mobilizing cytokines and osteocalcin-positive mononuclear cells in a mouse model and patients with peripheral artery disease.

METHODS AND RESULTS

We estimated the concentration of the stem-cell-mobilizing cytokines stromal cell-derived factor α (SDF-1α), granulocyte colony stimulating factor and stem cell factor in a mouse model of aortic calcification developed in osteoprotegerin-deficient (OPG(-/-)) mice, as well as in patient plasma samples. Calcification was estimated by a colorimetric assay of extracts of harvested mice aortas and by computed tomographic angiogram images in patients. The cytokine concentrations were assessed for association with the severity of calcification and the percentage of osteocalcin-positive mononuclear cells (OCN(+) MNC) using non-parametric analysis. The serum concentration of stromal SDF-1α and granulocyte-colony stimulating factor (G-CSF) were significantly greater in OPG(-/-) compared to control mice. The percentage of circulating OCN(+) MNC was correlated to the concentration of SDF-1α in OPG(-/-) mice. These cytokines also correlated with the severity of calcification in OPG(-/-) mice. Patients with more severe calcification had a higher plasma concentration of the cytokines than those with less marked aortic calcification. The concentrations also correlated with circulating OCN(+) MNC and aortic calcification volumes.

CONCLUSIONS

The association between stem cell cytokines, OCN(+) MNC and calcification suggests a possible role of bone-derived osteoprogenitor cells in the pathogenesis of vascular calcification.

Repeated intracoronary infusion of peripheral blood stem cells with G-CSF in patients with refractory ischemic heart failure--a pilot study

BACKGROUND

Recent investigations have suggested the clinical efficacy of granulocyte colony-stimulating factor (G-CSF) infusion alone or in combination with a single dose delivery of peripheral blood stem cells (PBSC) infusion in patients with myocardial infarction (MI) and congestive heart failure (HF). The current study tested the feasibility and effect of repeated intracoronary infusions PBSC and the mobilization of G-CSF in patients with refractory HF after MI.

METHODS AND RESULTS

Patients with recent large MI and a lower left ventricular ejection fraction (LVEF) were enrolled into one of the following 3 groups: Group R (n=15) received repeated intracoronary infusion of PBSC and one-dose of G-CSF; Group S (n=15) received a single infusion of PBSC and a G-CSF dose; and Group C (n=15) received neither PBSC nor a G-CSF dose. Cardiac performance was evaluated by echocardiography and single photon-emission computed tomography (SPECT). All the patients underwent 12-month follow-up. LVEF in Group R (47.00±4.90%) was significantly higher than that in Group S (44.40±3.87%, P<0.01) and Group C (40.80±3.41%, P<0.01). Similarly, the improvement of myocardial perfusion assessed by SPECT in Group R was more than that in Group S (P=0.012) and Group C (P<0.01). Neither death nor new MI occurred.

CONCLUSIONS

Repeated intracoronary infusions of PBSC plus mobilization of G-CSF might be an optional effective strategy for treating patients with refractory HF after recent large MI.

Role of cellular senescence in lifestyle-related disease

Epidemiological studies have shown that age is the chief risk factor for lifestyle-related diseases such as cardiovascular disease and diabetes, but the molecular mechanisms that underlie the increase in the risk of such diseases conferred by aging remain unclear. Recently, genetic analyses using various animal models have identified molecules that are crucial for aging. These include components of the DNA repair system, the tumor suppressor pathway, the telomere maintenance system, the insulin/Akt pathway, and other metabolic pathways. Interestingly, most of the molecules that influence the phenotypic changes of aging also regulate cellular senescence, suggesting a causative link between cellular senescence and aging. This review examines the hypothesis that cellular senescence might contribute to lifestyle-related disease.

Reduced ACTC1 expression might play a role in the onset of congenital heart disease by inducing cardiomyocyte apoptosis

BACKGROUND

The Cardiac α actin 1 gene (ACTC1) has been related to familial atrial septal defects. This study was set to explore a potential role of this gene in the formation of sporadic congenital heart disease (CHD).

METHODS AND RESULTS

Assessment of cardiac tissue samples from 33 patients with sporadic CHD (gestational age (GA) 18 weeks-49 months) with real-time RT-PCR, Western blotting and immunohistochemistry has revealed a markedly decreased ACTC1 expression in the majority of samples (78.8%) compared with autopsied normal heart tissue from aged-matched subjects (GA 17 weeks-36 months). Also, as shown by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay, the proportion of apoptotic cardiomyocytes in samples featuring down-regulated ACTC1 expression (Group 1) was significantly greater than those with normal expression (Group 2) and the controls (P<0.01). The proportion of apoptotic cells strongly correlated with the expression of ACTC1 (r=-0.918, P<0.01). A study of 2 essential genes involved in apoptosis, Caspase-3 and Bcl-2, confirmed that the former has significantly increased expression, whilst the latter has decreased expression in Group 1 than in the other groups (P<0.01). Transfection of a small interfering RNA targeting, Actc1 (Actc1-siRNA), to a cardiomyocyte cell line, H9C2, also detected more apoptotic cells.

CONCLUSIONS

Reduced ACTC1 expression might play a role in the onset of CHD through induction of cardiomyocyte apoptosis.

Cardiovascular side-effects of modern cancer therapy

Recent advances in chemotherapy have substantially improved the prognosis of cancer patients. However, many anticancer drugs, especially newly developed ;molecular-target drugs', such as the anti-HER2 blocking antibody and the anti-vascular endothelial growth factor antibody, have serious cardiovascular side-effects such as heart failure, thromboembolism, severe hypertension and lethal arrhythmia, which interrupt cancer treatment and decrease the patient's quality of life. Despite the increasing clinical significance, cardiologists have not been focusing enough of their attention on this issue. The major cardiovascular complications associated with anticancer drugs, and current diagnosis, treatment and prevention strategies are reviewed. Close collaborations between oncologists and cardiologists is necessary to tackle cardiovascular complications and advance cancer treatment.

Stromal cell biology--a way to understand the evolution of cardiovascular diseases

Stromal cells, composed of fibroblasts, microvascular endothelial cells, immune cells and inflammatory cells, are critical determinants of the mechanical properties and function of the heart and vasculature, and the mechanisms whereby these types of cells are activated are important to understand the progression of cardiovascular diseases. Emerging studies have suggested that the activation of autocrine and paracrine signaling pathways by stromal cell-derived growth factors, cytokines and bioactive molecules contributes to disease progression. Disruption of the stromal network will result in alterations in the geometry and function in these organs. Interventions targeting the stromal cells (eg, myofibroblasts, microvascular endothelial cells, inflammatory cells) by pharmacological agents or direct gene delivery/small interfering RNA would be potential novel therapeutic strategies to prevent/attenuate the progression of cardiovascular disorders.

A bibliometric study of the use of the classification and diagnostic systems in psychiatry over the last 25 years

BACKGROUND

Our purpose was to examine the use of classification and diagnostic systems in the field of psychiatry (CDSP) from a bibliometric perspective, over the period 1980-2005.

METHODS

We selected (in EMBASE and MEDLINE databases) documents that contained, in any of their sections, the descriptors 'psychiatr*', 'DSM*', 'ICD*', or 'diagnostic criteria',as well as other more specific descriptors. As a bibliometric indicator of production we applied Price's law. We also calculated the national participation index (PI) and correlated it with overall PI in biomedical and health sciences, and with PI in the discipline of psychiatry.

RESULTS

We obtained 20,564 original documents; 15,743 referred to the Diagnostic and Statistical Manual of Mental Disorders (DSM) and 3,106 to the International Classification of Diseases (ICD). Our results indicate non-fulfilment of Price's law, since scientific production on CDSP does not undergo exponential growth (correlation coefficient r = 0.9651, vs. r = 0.9927 after linear adjustment). Of the 10 journals with the highest impact factor in the field of psychiatry, the Journal of Clinical Psychiatry has the highest PI in the DSM subgroup (PI = 14.77), and the British Journal of Psychiatry in the ICD subgroup (PI = 1.54). The principal producer country is the United States (PI = 37.9), though in proportion to its production in the psychiatric field the ranking is headed by Finland. Only 10 countries, of the 20 major producers in health sciences, surpass their own PI in the field of psychiatry (Brazil, Italy, Japan, Austria, Spain, Germany, France, India, Switzerland, and China).

CONCLUSIONS

Over recent years, the use of CDSP (basically the DSM or ICD) in the scientific literature has increased. Nevertheless, the abstracts to these studies, included in the principal databases, should always specify the diagnostic criteria employed, with a view to increasing information levels and reliability for the reader.