Prognostic biomarker soluble ST2 exhibits diurnal variation in chronic heart failure patients

Aim: Soluble suppression of tumorigenicity-2 (sST2) is a strong prognostic biomarker in heart failure. The emerging understanding of circadian biology in cardiovascular disease may lead to novel applications in prognosis and diagnosis and may provide insight into mechanistic aspects of the disease–biomarker interaction. So far, it is unknown whether sST2 exhibits a diurnal rhythm. Repeated measurements of sST2 may aid in clinical decision making. The goal of this study was to investigate whether sST2 exhibits diurnal variation in patients with heart failure with reduced ejection fraction (HFrEF) and in control subjects, thereby enhancing its diagnostic and prognostic values. Methods and results: The study comprised 32 subjects: 16 HFrEF patients and 16 controls. Blood was collected at seven subsequent time points during a 24 h time period. sST2, N-terminal pro-B-type natriuretic peptide (NT-proBNP), melatonin, and cortisol were measured from serum. Peak values of sST2 clustered at daytime (modal value: 5 p.m.) in 87.6% of all subjects (81.3% of patients, P = 0.021; 93.8% of controls, P = 0.001), and minimum concentrations at night-time (modal value: 5 a.m.) in 84.4% (87.5% of patients, P = 0.004 81.3% of controls, P = 0.021). A cosinor analysis of mean normalized sST2 values revealed significant cosine shaped 24 h oscillations of patients (P = 0.026) and controls (P = 0.037). NT-proBNP in contrast did not show a diurnal rhythm, while melatonin and cortisol patterns were intact in all subjects. Conclusions: sST2 exhibits a diurnal rhythm with lower values in the morning than in the late afternoon. This new insight could lead to refinement of its diagnostic and prognostic values through specified and consistent sampling times with repeated measurements. For example, by measuring sST2 during the afternoon, when levels are at their highest, false negatives on prognosis prediction could be avoided

Inotropic therapy in patients with advanced heart failure: a clinical consensus statement from the Heart Failure Association of the European Society of Cardiology

This clinical consensus statement reviews the use of inotropic support in patients with advanced heart failure. The current guidelines only support use of inotropes in the setting of acute decompensated heart failure with evidence of organ malperfusion or shock. However, inotropic support may be reasonable in other patients with advanced heart failure without acute severe decompensation. The clinical evidence supporting use of inotropes in these situations is reviewed. Particularly, patients with persistent congestion, systemic hypoperfusion, or advanced heart failure with need for palliation, and specific situations relevant to implantation of left ventricular assist devices or heart transplantation are discussed. Traditional and novel drugs with inotropic effects are discussed and use of guideline-directed therapy during inotropic support is reviewed. Finally, home inotropic therapy is described, and palliative care and end-of-life aspects are reviewed in relation to management of ongoing inotropic support (including guidance for maintenance and weaning of chronic inotropic therapy support). Cardiolog

Cardiac recovery by stem and progenitor cells

The adult human heart has a minimal ability to regenerate myocardium. Therefore, loss of viable cardiomyocytes in cardiac disease, such as myocardial infarction (MI), may lead to heart failure. After evaluating the regenerative potential of several stem cell sources of cardiac myocytes and vascular cells (chapter 2), we created a mouse model of MI and cell transplantation which allows long term phenotypical analysis of engrafted human stem and progenitor cells, and used magnetic resonance imaging (MRI) to monitor cardiac function (chapter 3). We thus performed the first long term study of human embryonic stem cell-derived cardiomyocytes (hESC-CM) in uninjured and infarcted mouse hearts, and found that hESC-CM survive, integrate and mature in the host myocardium for at least 12 weeks. HESC-CM transplantation improved heart function post-MI at 4 weeks compared to differentiated hESCs devoid of cardiomyocytes, but this was not sustained at 12 weeks (chapter 4). Comparing the effects of injection of hESC-CM at different dosages with hESC-non-CM derivatives, culture medium or no injection in the same experimental model, we demonstrate that both hESC-CM and hESC-non-CM provide long term functional improvement compared to vehicle- or no injection even though only cardiomyocytes formed persistent grafts. Importantly, increasing numbers of hESC-CM for transplantation resulted in no additional functional benefit. In addition, we confirmed evidence of a paracrine contribution of the transplanted hESC-CM by demonstrating increased vascularization in the infarcted heart associated specifically with transplantation of these cells (chapter 5). Because the grafted cells were usually surrounded by a fibrotic layer, we determined its composition with respect to extracellular matrix type and origin, and found a contribution of both host and donor cells. In addition, we characterized the integrin expression of hESC-CM in vitro and at various time points post-transplantation. Co-transplanted hESC-derived endothelial cells formed a capillary network through the fibrotic layer that communicated with the mouse vasculature, supporting extended graft survival and maturation over a 6 month period (chapter 6). We further specified the role and suitability of vasculogenic cells in cardiac regeneration using mice and human cells with a deficiency of endoglin, an accessory TGFbeta-receptor present on mononuclear cells (MNCs). Defects in mutant mice in vascularization and cardiac function post-MI could be rescued by intravenous injection of healthy donor MNCs, but not MNCs from patients with the gene mutation. This indicates that cardiovascular patients, who often have defects in their MNCs and endothelial progenitor cells, may benefit from transplantation of cells with high endoglin expression, and matched heterologous cells may be preferred (chapter 7). Finally, we show that human heart-derived cardiomyocyte progenitor cells (CMPCs) and CMPC-CM prevented cardiac dilatation and deterioration of cardiac function for at least 12 weeks after MI. In addition, CMPCs differentiated in vivo into cardiomyocytes, smooth muscle cells and endothelial cells (chapter 8). In conclusion, several cell types improve cardiac function but some problems need to be solved, and further investigation into the underlying mechanisms is required for optimization in the choice of cell number and type so that clinical strategies can be properly defined

Human embryonic stem cell-derived cardiomyocytes and cardiac repair in rodents.

Cell transplantation may restore heart function in disease associated with loss or dysfunction of cardiomyocytes. Recently, Laflamme et al reported an improvement in cardiac function in immunodeficient rats 4 weeks after coronary artery ligation and injection of human embryonic stem cell-derived cardiomyocytes (hESC-CMs). We have recently carried out a comparable study transplanting hESC-CMs to the hearts of mice with myocardial infarction. Our findings were similar up to the 4-week time point, with significant improvements in cardiac function. However, our follow-up was longer, and, at 3 months, the difference between mice receiving cardiomyocytes and those receiving other cells was no longer significant. Hypothesizing that the improvement observed by Laflamme et al may have been more likely to be sustained long term because the grafts in their study appeared larger, we injected 3 times as many cells. Although this resulted in a significantly increased graft size, we again observed a functional improvement at 1 month but not at 3 months. Our results show that midterm data in these kinds of experiments must be interpreted with caution and longer-term follow-up is essential to draw conclusions on the efficacy of cardiac cell transplantation. Furthermore, our findings demonstrate the unlikely success of merely generating and injecting more cells of the same type to increase functional improvement

Usefulness and applicability of femorofemoral crossover bypass grafting.

We examined the usefulness of femorofemoral crossover bypass grafting ( FFC) and factors influencing its outcome by retrospectively analyzing all FFCs performed in our hospital over a 5-year period, focusing on both patency rates and clinical efficacy. For 95 patients Kaplan- Meier patency rates were calculated ( follow- up 40.4 +/- 3.0 months). Clinical outcome was defined according to Rutherford's standardized categories. The influence of cardiovascular risk factors and technical characteristics on outcome was determined. Clinical status of the limb remained improved in 89%. One- and 5- year primary, primary assisted, and secondary patency rates were 88.2% and 57.3%, 90.6% and 62.4%, and 92.6% and 68.1%, respectively. Clinical outcome of the limb was better in patients with <50% stenosis in the femoral arteries preoperatively (p = 0.033). No predictors for patency rates were identified. FFCs are effective in the medium long term for patients in all age categories independently of cardiovascular risk factors. The best predictor of clinical outcome is the preoperative degree of stenosis, with a better outcome for patients affected by <50% stenosis. Success of FFC cannot be reliably measured by graft patency alone but should be assessed by combining patency rates and clinical outcome according to standardized categories

Embryonic template-based generation and purification of pluripotent stem cell-derived cardiomyocytes for heart repair

Cardiovascular disease remains a leading cause of death in Western countries. Many types of cardiovascular diseases are due to a loss of functional cardiomyocytes, which can result in irreversible cardiac failure. Since the adult human heart has limited regenerative potential, cardiac transplantation is still the only effective therapy to address this cardiomyocyte loss. However, drawbacks, such as immune rejection and insufficient donor availability, are limiting this last-resort solution. Recent developments in the stem cell biology field have improved the potential of cardiac regeneration. Improvements in reprogramming strategies of differentiated adult cells into induced pluripotent stem cells, together with increased efficiency of directed differentiation of pluripotent stem cells toward cardiac myocytes, have brought cell-based heart muscle regeneration a few steps closer to the clinic. In this review, we outline the status of research on cardiac regeneration with a focus on directed differentiation of pluripotent stem cells toward the cardiac lineage

Human cardiomyocyte progenitor cell transplantation preserves long-term function of the infarcted mouse myocardium

AIMS: Recent clinical studies revealed that positive results of cell transplantation on cardiac function are limited to the short- and mid-term restoration phase following myocardial infarction (MI), emphasizing the need for long-term follow-up. These transient effects may depend on the transplanted cell-type or its differentiation state. We have identified a population of cardiomyocyte progenitor cells (CMPCs) capable of differentiating efficiently into beating cardiomyocytes, endothelial cells, and smooth muscle cells in vitro. We investigated whether CMPCs or pre-differentiated CMPC-derived cardiomyocytes (CMPC-CM) are able to restore the injured myocardium after MI in mice. METHODS AND RESULTS: MI was induced in immunodeficient mice and was followed by intra-myocardial injection of CMPCs, CMPC-CM, or vehicle. Cardiac function was measured longitudinally up to 3 months post-MI using 9.4 Tesla magnetic resonance imaging. The fate of the human cells was determined by immunohistochemistry. Transplantation of CMPCs or CMPC-CM resulted in a higher ejection fraction and reduced the extent of left ventricular remodelling up to 3 months after MI when compared with vehicle-injected animals. CMPCs and CMPC-CM generated new cardiac tissue consisting of human cardiomyocytes and blood vessels. Fusion of human nuclei with murine nuclei was not observed. CONCLUSION: CMPCs differentiated into the same cell types in situ as can be obtained in vitro. This excludes the need for in vitro pre-differentiation, making CMPCs a promising source for (autologous) cell-based therapy.

Human embryonic stem cell-derived cardiomyocytes improve cardiac function after myocardial infarction: paracrine effects outweigh the contribution of active contractile force

Stem cells & developmental biolog

Extracellular matrix formation after transplantation of human embryonic stem cell-derived cardiomyocytes

Transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CM) for cardiac regeneration is hampered by the formation of fibrotic tissue around the grafts, preventing electrophysiological coupling. Investigating this process, we found that: (1) beating hESC-CM in vitro are embedded in collagens, laminin and fibronectin, which they bind via appropriate integrins; (2) after transplantation into the mouse heart, hESC-CM continue to secrete collagen IV, XVIII and fibronectin; (3) integrin expression on hESC-CM largely matches the matrix type they encounter or secrete in vivo; (4) co-transplantation of hESC-derived endothelial cells and/or cardiac progenitors with hESC-CM results in the formation of functional capillaries; and (5) transplanted hESC-CM survive and mature in vivo for at least 24 weeks. These results form the basis of future developments aiming to reduce the adverse fibrotic reaction that currently complicates cell-based therapies for cardiac disease, and to provide an additional clue towards successful engraftment of cardiomyocytes by co-transplanting endothelial cells

Prognostic biomarker soluble ST2 exhibits diurnal variation in chronic heart failure patients

AIM: Soluble suppression of tumorigenicity-2 (sST2) is a strong prognostic biomarker in heart failure. The emerging understanding of circadian biology in cardiovascular disease may lead to novel applications in prognosis and diagnosis and may provide insight into mechanistic aspects of the disease-biomarker interaction. So far, it is unknown whether sST2 exhibits a diurnal rhythm. Repeated measurements of sST2 may aid in clinical decision making. The goal of this study was to investigate whether sST2 exhibits diurnal variation in patients with heart failure with reduced ejection fraction (HFrEF) and in control subjects, thereby enhancing its diagnostic and prognostic values. METHODS AND RESULTS: The study comprised 32 subjects: 16 HFrEF patients and 16 controls. Blood was collected at seven subsequent time points during a 24 h time period. sST2, N-terminal pro-B-type natriuretic peptide (NT-proBNP), melatonin, and cortisol were measured from serum. Peak values of sST2 clustered at daytime (modal value: 5 p.m.) in 87.6% of all subjects (81.3% of patients, P = 0.021; 93.8% of controls, P = 0.001), and minimum concentrations at night-time (modal value: 5 a.m.) in 84.4% (87.5% of patients, P = 0.004 81.3% of controls, P = 0.021). A cosinor analysis of mean normalized sST2 values revealed significant cosine shaped 24 h oscillations of patients (P = 0.026) and controls (P = 0.037). NT-proBNP in contrast did not show a diurnal rhythm, while melatonin and cortisol patterns were intact in all subjects. CONCLUSIONS: sST2 exhibits a diurnal rhythm with lower values in the morning than in the late afternoon. This new insight could lead to refinement of its diagnostic and prognostic values through specified and consistent sampling times with repeated measurements. For example, by measuring sST2 during the afternoon, when levels are at their highest, false negatives on prognosis prediction could be avoided