Generation and characterisation of scalable and stable human pluripotent stem cell-derived microvascular-like endothelial cells for cardiac applications.

Coronary microvascular disease (CMD) and its progression towards major adverse coronary events pose a significant health challenge. Accurate in vitro investigation of CMD requires a robust cell model that faithfully represents the cells within the cardiac microvasculature. Human pluripotent stem cell-derived endothelial cells (hPSC-ECs) offer great potential; however, they are traditionally derived via differentiation protocols that are not readily scalable and are not specified towards the microvasculature. Here, we report the development and comprehensive characterisation of a scalable 3D protocol enabling the generation of phenotypically stable cardiac hPSC-microvascular-like ECs (hPSC-CMVECs) and cardiac pericyte-like cells. These were derived by growing vascular organoids within 3D stirred tank bioreactors and subjecting the emerging 3D hPSC-ECs to high-concentration VEGF-A treatment (3DV). Not only did this promote phenotypic stability of the 3DV hPSC-ECs; single cell-RNA sequencing (scRNA-seq) revealed the pronounced expression of cardiac endothelial- and microvascular-associated genes. Further, the generated mural cells attained from the vascular organoid exhibited markers characteristic of cardiac pericytes. Thus, we present a suitable cell model for investigating the cardiac microvasculature as well as the endothelial-dependent and -independent mechanisms of CMD. Moreover, owing to their phenotypic stability, cardiac specificity, and high angiogenic potential, the cells described within would also be well suited for cardiac tissue engineering applications.

International evaluation study of a highly efficient culture assay for detection of residual human pluripotent stem cells in cell therapies.

Aim & methods: The Health and Environmental Sciences Institute Cell Therapy-TRAcking, Circulation & Safety Technical Committee launched an international, multisite study to evaluate the sensitivity and reproducibility of the highly efficient culture (HEC) assay, an in vitro assay to detect residual undifferentiated human pluripotent stem cells (hPSCs) in cell therapy products. Results: All facilities detected colonies of human induced pluripotent stem cells (hiPSCs) when five hiPSCs were spiked into 1 million hiPSC-derived cardiomyocytes. Spiking with a trace amount of hiPSCs revealed that repeatability accounts for the majority of reproducibility while the true positive rate was high. Conclusion: The results indicate that the HEC assay is highly sensitive and robust and can be generally applicable for tumorigenicity evaluation of hPSC-derived cell therapy products.

Regenerative Neurology and Regenerative Cardiology: Shared Hurdles and Achievements.

From the first success in cultivation of cells in vitro, it became clear that developing cell and/or tissue specific cultures would open a myriad of new opportunities for medical research. Expertise in various in vitro models has been developing over decades, so nowadays we benefit from highly specific in vitro systems imitating every organ of the human body. Moreover, obtaining sufficient number of standardized cells allows for cell transplantation approach with the goal of improving the regeneration of injured/disease affected tissue. However, different cell types bring different needs and place various types of hurdles on the path of regenerative neurology and regenerative cardiology. In this review, written by European experts gathered in Cost European action dedicated to neurology and cardiology-Bioneca, we present the experience acquired by working on two rather different organs: the brain and the heart. When taken into account that diseases of these two organs, mostly ischemic in their nature (stroke and heart infarction), bring by far the largest burden of the medical systems around Europe, it is not surprising that in vitro models of nervous and heart muscle tissue were in the focus of biomedical research in the last decades. In this review we describe and discuss hurdles which still impair further progress of regenerative neurology and cardiology and we detect those ones which are common to both fields and some, which are field-specific. With the goal to elucidate strategies which might be shared between regenerative neurology and cardiology we discuss methodological solutions which can help each of the fields to accelerate their development.

Transcriptional co-activators YAP1-TAZ of Hippo signalling in doxorubicin-induced cardiomyopathy.

AIMS: Hippo signalling is an evolutionarily conserved pathway that controls organ size by regulating apoptosis, cell proliferation, and stem cell self-renewal. Recently, the pathway has been shown to exert powerful growth regulatory activity in cardiomyocytes. However, the functional role of this stress-related and cell death-related pathway in the human heart and cardiomyocytes is not known. In this study, we investigated the role of the transcriptional co-activators of Hippo signalling, YAP and TAZ, in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in response to cardiotoxic agents and investigated the effects of modulating the pathway on cardiomyocyte function and survival. METHODS AND RESULTS: RNA-sequencing analysis of human heart samples with doxorubicin-induced end-stage heart failure and healthy controls showed that YAP and ERBB2 (HER2) as upstream regulators of differentially expressed genes correlated with doxorubicin treatment. Thus, we tested the effects of doxorubicin on hiPSC-CMs in vitro. Using an automated high-content screen of 96 clinically relevant antineoplastic and cardiotherapeutic drugs, we showed that doxorubicin induced the highest activation of YAP/TAZ nuclear translocation in both hiPSC-CMs and control MCF7 breast cancer cells. The overexpression of YAP rescued doxorubicin-induced cell loss in hiPSC-CMs by inhibiting apoptosis and inducing proliferation. In contrast, silencing of YAP and TAZ by siRNAs resulted in elevated mitochondrial membrane potential loss in response to doxorubicin. hiPSC-CM calcium transients did not change in response to YAP/TAZ silencing. CONCLUSIONS: Our results suggest that Hippo signalling is involved in clinical anthracycline-induced cardiomyopathy. Modelling with hiPSC-CMs in vitro showed similar responses to doxorubicin as adult cardiomyocytes and revealed a potential cardioprotective effect of YAP in doxorubicin-induced cardiotoxicity.

Anti-cancer drugs-induced arterial injury: risk stratification, prevention, and treatment.

Vascular side effects of standard chemotherapeutic drugs and novel anti-tumor agents complicate treatment cycles, increase non-cancer-related mortality rates, and decrease the quality of life in cancer survivors. Arterial thromboembolic events (ATEE) are associated with most anti-cancer medications. Previous articles have reported a variety of vascular events including ST-segment elevation myocardial infarction as one of the most severe acute arterial attacks. Cardiologists should play an early role in identifying those at high risk for vascular complications and tailor anti-thrombotic therapies in keeping with thromboembolic and bleeding risks. Early preventive steps and individualized chemotherapy may decrease anti-tumor treatment-related vascular events. Here, we aim to provide an extensive review of anti-tumor drug-induced vascular injury (DIVI), pathomechanisms, and risk stratification underlining arterial events. We give a summary of clinical manifestations, treatment options, and possible preventive measures of DIVI. Additionally, the treatment of modifiable risk factors and tailored choice of chemotherapy must be considered in all oncology patients to prevent DIVI. We propose a complex tool for ATEE risk stratification which is warranted for early prediction leading to less frequent complications in cancer patients.

New artery of knowledge: 3D models of angiogenesis.

Angiogenesis and vasculogenesis are complex processes by which new blood vessels are formed and expanded. They play a pivotal role not only in physiological development and growth and tissue and organ repair, but also in a range of pathological conditions, from tumour formation to chronic inflammation and atherosclerosis. Understanding the multistep cell-differentiation programmes and identifying the key molecular players of physiological angiogenesis/vasculogenesis are critical to tackle pathological mechanisms. While many questions are yet to be answered, increasingly sophisticated in vitro, in vivo and ex vivo models of angiogenesis/vasculogenesis, together with cutting-edge imaging techniques, allowed for recent major advances in the field. This review aims to summarise the three-dimensional models available to study vascular network formation and to discuss advantages and limitations of the current systems.

Stem cell death and survival in heart regeneration and repair.

Cardiovascular diseases are major causes of mortality and morbidity. Cardiomyocyte apoptosis disrupts cardiac function and leads to cardiac decompensation and terminal heart failure. Delineating the regulatory signaling pathways that orchestrate cell survival in the heart has significant therapeutic implications. Cardiac tissue has limited capacity to regenerate and repair. Stem cell therapy is a successful approach for repairing and regenerating ischemic cardiac tissue; however, transplanted cells display very high death percentage, a problem that affects success of tissue regeneration. Stem cells display multipotency or pluripotency and undergo self-renewal, however these events are negatively influenced by upregulation of cell death machinery that induces the significant decrease in survival and differentiation signals upon cardiovascular injury. While efforts to identify cell types and molecular pathways that promote cardiac tissue regeneration have been productive, studies that focus on blocking the extensive cell death after transplantation are limited. The control of cell death includes multiple networks rather than one crucial pathway, which underlies the challenge of identifying the interaction between various cellular and biochemical components. This review is aimed at exploiting the molecular mechanisms by which stem cells resist death signals to develop into mature and healthy cardiac cells. Specifically, we focus on a number of factors that control death and survival of stem cells upon transplantation and ultimately affect cardiac regeneration. We also discuss potential survival enhancing strategies and how they could be meaningful in the design of targeted therapies that improve cardiac function.

Lipopolysaccharide responsiveness is an independent predictor of death in patients with chronic heart failure.

BACKGROUND: The origin of pro-inflammatory activation in chronic heart failure (HF) remains a matter of debate. Lipopolysaccharide (LPS) may enter the blood stream through the morphologically altered and leaky gut barrier. We hypothesized that lower LPS reactivity would be associated with worse survival as compared to normal or higher LPS reactivity. METHODS: LPS responsiveness was studied in 122 patients with chronic HF (mean±SD: age 67.3±10.3 years, 24 female, New York Heart Association class [NYHA] class: 2.5±0.8, left ventricular ejection fraction [LVEF]: 33.5±12.5%) and 27 control subjects of similar age (63.7±7.7 years, p>0.05). Reference LPS was added at increasing doses to ex vivo whole blood samples and necrosis factor-α (TNFα) was measured. Patients were subgrouped into good- and poor-responder status according to their potential to react to increasing doses of LPS (delta TNFα secretion). The optimal cut-off value was calculated by receiver-operator characteristic curve (ROC) analysis. RESULTS: A total of 56 patients with chronic HF died from any cause during follow-up. At 24 months, cumulative mortality was 16.4% (95% confidence interval 16.0-16.7%). The delta TNFα value representing the optimal cut-off for the prediction of mortality was 1522 pg/mL (24 months) with a sensitivity of 49.3% (95% confidence interval 37.2-61.4%) and specificity of 81.5% (95% confidence interval 61.9-93.6%). LPS responder status remained an independent predictor of death after multivariable adjustment (hazard ratio 0.09 for good- vs. poor-responders, 95% confidence interval 0.01-0.67, p<0.05). CONCLUSIONS: LPS responsiveness in patients with chronic HF is an independent predictor of death.

Three Huntington's Disease Specific Mutation-Carrying Human Embryonic Stem Cell Lines Have Stable Number of CAG Repeats upon In Vitro Differentiation into Cardiomyocytes.

Huntington disease (HD; OMIM 143100), a progressive neurodegenerative disorder, is caused by an expanded trinucleotide CAG (polyQ) motif in the HTT gene. Cardiovascular symptoms, often present in early stage HD patients, are, in general, ascribed to dysautonomia. However, cardio-specific expression of polyQ peptides caused pathological response in murine models, suggesting the presence of a nervous system-independent heart phenotype in HD patients. A positive correlation between the CAG repeat size and severity of symptoms observed in HD patients has also been observed in in vitro HD cellular models. Here, we test the suitability of human embryonic stem cell (hESC) lines carrying HD-specific mutation as in vitro models for understanding molecular mechanisms of cardiac pathology seen in HD patients. We have differentiated three HD-hESC lines into cardiomyocytes and investigated CAG stability up to 60 days after starting differentiation. To assess CAG stability in other tissues, the lines were also subjected to in vivo differentiation into teratomas for 10 weeks. Neither directed differentiation into cardiomyocytes in vitro nor in vivo differentiation into teratomas, rich in immature neuronal tissue, led to an increase in the number of CAG repeats. Although the CAG stability might be cell line-dependent, induced pluripotent stem cells generated from patients with larger numbers of CAG repeats could have an advantage as a research tool for understanding cardiac symptoms of HD patients.

Signaling via PI3K/FOXO1A pathway modulates formation and survival of human embryonic stem cell-derived endothelial cells.

Vascular derivatives of human embryonic stem cells (hESC) are being developed as sources of tissue-specific cells for organ regeneration. However, identity of developmental pathways that modulate the specification of endothelial cells is not known yet. We studied phosphatidylinositol 3-kinase (PI3K)-Forkhead box O transcription factor 1A (FOXO1A) pathways during differentiation of hESC toward endothelial lineage and on proliferation, maturation, and cell death of hESC-derived endothelial cells (hESC-EC). During differentiation of hESC, expression of FOXO1A transcription factor was linked to the expression of a cluster of angiogenesis- and vascular remodeling-related genes. PI3K inhibitor LY294002 activated FOXO1A and induced formation of CD31(+) hESC-EC. In contrast, differentiating hESC with silenced FOXO1A by small interfering RNA (siRNA) showed lower mRNA levels of CD31 and angiopoietin2. LY294002 decreased proliferative activity of purified hESC-EC, while FOXO1A siRNA increased their proliferation. LY294002 inhibits migration and tube formation of hESC-EC; in contrast, FOXO1A siRNA increased in vitro tube formation activity of hESC-EC. After in vivo conditioning of cells in athymic nude rats, cells retain their low FOXO1A expression levels. PI3K/FOXO1A pathway is important for function and survival of hESC-EC and in the regulation of endothelial cell fate. Understanding these properties of hESC-EC may help in future applications for treatment of injured organs.

Pathogen sensing pathways in human embryonic stem cell derived-endothelial cells: role of NOD1 receptors.

Human embryonic stem cell-derived endothelial cells (hESC-EC), as well as other stem cell derived endothelial cells, have a range of applications in cardiovascular research and disease treatment. Endothelial cells sense Gram-negative bacteria via the pattern recognition receptors (PRR) Toll-like receptor (TLR)-4 and nucleotide-binding oligomerisation domain-containing protein (NOD)-1. These pathways are important in terms of sensing infection, but TLR4 is also associated with vascular inflammation and atherosclerosis. Here, we have compared TLR4 and NOD1 responses in hESC-EC with those of endothelial cells derived from other stem cells and with human umbilical vein endothelial cells (HUVEC). HUVEC, endothelial cells derived from blood progenitors (blood outgrowth endothelial cells; BOEC), and from induced pluripotent stem cells all displayed both a TLR4 and NOD1 response. However, hESC-EC had no TLR4 function, but did have functional NOD1 receptors. In vivo conditioning in nude rats did not confer TLR4 expression in hESC-EC. Despite having no TLR4 function, hESC-EC sensed Gram-negative bacteria, a response that was found to be mediated by NOD1 and the associated RIP2 signalling pathways. Thus, hESC-EC are TLR4 deficient but respond to bacteria via NOD1. This data suggests that hESC-EC may be protected from unwanted TLR4-mediated vascular inflammation, thus offering a potential therapeutic advantage.

Immunosuppressive agents modulate function, growth, and survival of cardiomyocytes and endothelial cells derived from human embryonic stem cells.

Cardiac cell replacement therapy by using human embryonic stem cell (hESC) derivatives remains a potential approach to regenerate myocardium. The major hurdles to clinical application of this technology are immunogenicity and post-transplantation cell death. Here we examined the effects of calcineurin-targeting immunosuppressants cyclosporine A (CsA) and FK506, as well as rapamycin and a selective inhibitor of calcineurin-binding downstream nuclear factor of activated T-cell (NFAT) transcription factor VIVIT on the proliferative activity, function, and survival of hESC-derived cardiomyocytes (hESC-CM) and endothelial cells (hESC-EC) in culture. As shown by automated microscopy, treatments with CsA, FK506, and rapamycin all decreased proliferation, reducing the percentage of hESC-CM and hESC-EC with the mitotic marker Ki67(+) by as much as 60% and 74%, respectively. Administration of the cell permeable analogue 11R-VIVIT protein did not modulate their proliferative activity. All immunosuppressants reversed the proapoptotic effect of chelerythrine in hESC-CM demonstrating an inhibitory role of calcineurin/NFAT and mammalian target of rapamycin (mTOR) pathways in hESC-CM survival (using apoptotic marker caspase-3), whereas the protection was less obvious in hESC-EC exposed to H2O2. Immunosuppressants did not affect cell viability in hESC-EC. Our results show that immunosuppressants reduce proliferation, while offsetting cell loss to a smaller extent by reduction in apoptosis of hESC-CM. Immunosuppressant therapy would be compatible with stem cell transplantation, but the resulting reduction in graft expansion capabilities would potentially necessitate implantation of increased cell numbers when immunosuppressants are given. The effects of NFAT-binding immunosuppressant molecules, which do not affect hESC-CM proliferation, may point the way forward for new classes of compounds better suited to cell implantation.

Prevention of liver cancer cachexia-induced cardiac wasting and heart failure.

AIMS: Symptoms of cancer cachexia (CC) include fatigue, shortness of breath, and impaired exercise capacity, which are also hallmark symptoms of heart failure (HF). Herein, we evaluate the effects of drugs commonly used to treat HF (bisoprolol, imidapril, spironolactone) on development of cardiac wasting, HF, and death in the rat hepatoma CC model (AH-130). METHODS AND RESULTS: Tumour-bearing rats showed a progressive loss of body weight and left-ventricular (LV) mass that was associated with a progressive deterioration in cardiac function. Strikingly, bisoprolol and spironolactone significantly reduced wasting of LV mass, attenuated cardiac dysfunction, and improved survival. In contrast, imidapril had no beneficial effect. Several key anabolic and catabolic pathways were dysregulated in the cachectic hearts and, in addition, we found enhanced fibrosis that was corrected by treatment with spironolactone. Finally, we found cardiac wasting and fibrotic remodelling in patients who died as a result of CC. In living cancer patients, with and without cachexia, serum levels of brain natriuretic peptide and aldosterone were elevated. CONCLUSION: Systemic effects of tumours lead not only to CC but also to cardiac wasting, associated with LV-dysfunction, fibrotic remodelling, and increased mortality. These adverse effects of the tumour on the heart and on survival can be mitigated by treatment with either the ß-blocker bisoprolol or the aldosterone antagonist spironolactone. We suggest that clinical trials employing these agents be considered to attempt to limit this devastating complication of cancer.

Assessment of serum cotinine in patients with chronic heart failure: self-reported versus objective smoking behaviour.

BACKGROUND: Smoking is a major risk factor in the development of coronary artery disease and thus chronic heart failure (HF). The value of self-reported smoking behaviour has not been validated in patients with HF. We sought to assess serum cotinine levels, a marker of recent tobacco exposure, in a cohort of clinically stable patients with chronic HF. METHODS AND RESULTS: We analysed serum cotinine values in 75 patients with chronic HF [mean age ± SD 64 ± 16 years, 85 % male, left ventricular ejection fraction 30 ± 1 %, New York Heart Association class (I/II vs. III/IV) 73 %/27 %, haemoglobin (Hb) 13.4 ± 1.5 g/dL, serum creatinine 1.21 ± 0.51 mg/dL] and 30 control subjects of similar age (63 ± 11 years, 43 % male, Hb 14.1 ± 1.5 g/dL, creatinine 1.12 ± 0.92 mg/dL) using a chemiluminescence immunoassay. Patients were interviewed about their smoking habits, and routine laboratory parameters were analysed. In patients with HF, cotinine values ranged from undetectable to 829 µg/L (mean 110 ± 208 µg/L). Similar findings were evident in healthy subjects with cotinine ranging from undetectable to 860 µg/L (mean 105 ± 208 µg/L). Serum cotinine levels correlated with leukocyte count and haemoglobin concentration (both p < 0.05). Self-reported smoking behaviour did not correspond to serum cotinine level in serum in 16.9 % of the patients with chronic HF. No such finding was evident in control subjects. CONCLUSIONS: Serum cotinine measurement provides an easily applicable means to analyse smoking behaviour in patients with chronic HF. Its assessment may permit analysis of smoking deception in daily clinical routine.

Stem cell-derived endothelial cells for cardiovascular disease: a therapeutic perspective.

Stem cell therapy and organ regeneration are therapeutic approaches that will, we suggest, become mainstream for the treatment of human disease. Endothelial cells, which line the luminal surface of every vessel in the body, are essential components in any organ regeneration programme. There are a number of potentially therapeutic endothelial cell types, including embryonic, adult progenitor and induced pluripotent stem cell-derived endothelial cells, as well as host vascular cells. The features (benefits as well as disadvantages) of each cell type that make them potentially useful in therapy are important to consider. The field of stem cell biology is well developed in terms of protocols for generating endothelium. However, where there is a distinct and urgent unmet need for knowledge concerning how the endothelial cells from these different sources function as endothelium and how susceptible they may be to inflammation and atherosclerosis. Furthermore, where stem cells have been used in clinical trials there is little commonality in protocols for deriving the cells (and thereby the specific phenotype of cells used), administering the cells, dosing the cells and/or in assessing efficacy attributed to the cells themselves. This review discusses these and other issues relating to stem cell-derived endothelial cells in cell therapy for cardiovascular disease.

Modulation of human embryonic stem cell-derived cardiomyocyte growth: a testbed for studying human cardiac hypertrophy?

Human embryonic stem cell-derived cardiomyocytes (hESC-CM) are being developed for tissue repair and as a model system for cardiac physiology and pathophysiology. However, the signaling requirements of their growth have not yet been fully characterized. We showed that hESC-CM retain their capacity for increase in size in long-term culture. Exposing hESC-CM to hypertrophic stimuli such as equiaxial cyclic stretch, angiotensin II, and phenylephrine (PE) increased cell size and volume, percentage of hESC-CM with organized sarcomeres, levels of ANF, and cytoskeletal assembly. PE effects on cell size were separable from those on cell cycle. Changes in cell size by PE were completely inhibited by p38-MAPK, calcineurin/FKBP, and mTOR blockers. p38-MAPK and calcineurin were also implicated in basal cell growth. Inhibitors of ERK, JNK, and CaMK II partially reduced PE effects; PKG or GSK3ß inhibitors had no effect. The role of p38-MAPK was confirmed by an additional pharmacological inhibitor and adenoviral infection of hESC-CM with a dominant-inhibitory form of p38-MAPK. Infection of hESC-CM with constitutively active upstream MAP2K3b resulted in an increased cell size, sarcomere and cytoskeletal assembly, elongation of the cells, and induction of ANF mRNA levels. siRNA knockdown of p38-MAPK inhibited PE-induced effects on cell size. These results reveal an important role for active protein kinase signaling in hESC-CM growth and hypertrophy, with potential implications for hESC-CM as a novel in vitro test system. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited".

Cardiomyocytes from embryonic stem cells: towards human therapy.

BACKGROUND: Despite improvements in survival with current therapies, it is now clear that major cardiovascular event rates in patients remain high. Cardiac cell replacement therapy by using human embryonic stem cell-derived cardiomyocytes has emerged as a promising future approach to regenerate functional myocardium. However, there are still many hurdles to be overcome for the clinical application of these cells. OBJECTIVE: This review describes the embryonic stem cell system, their differentiation into cardiomyocytes, and functional characterization of the cardiac lineage derivatives in culture and upon in vivo engraftment in animal models. RESULTS/CONCLUSION: A better understanding of the characteristics of the cardiomyocytes from human embryonic stem cells not only predicts their behaviour after implantation but will also help in the design of future strategies for cardiac regeneration in vivo.

Effect of intravenous iron sucrose on exercise tolerance in anemic and nonanemic patients with symptomatic chronic heart failure and iron deficiency FERRIC-HF: a randomized, controlled, observer-blinded trial.

OBJECTIVES: We tested the hypothesis that intravenous iron improves exercise tolerance in anemic and nonanemic patients with symptomatic chronic heart failure (CHF) and iron deficiency. BACKGROUND: Anemia is common in heart failure. Iron metabolism is disturbed, and administration of iron might improve both symptoms and exercise tolerance. METHODS: We randomized 35 patients with CHF (age 64 +/- 13 years, peak oxygen consumption [pVO2] 14.0 +/- 2.7 ml/kg/min) to 16 weeks of intravenous iron (200 mg weekly until ferritin >500 ng/ml, 200 mg monthly thereafter) or no treatment in a 2:1 ratio. Ferritin was required to be <100 ng/ml or ferritin 100 to 300 ng/ml with transferrin saturation <20%. Patients were stratified according to hemoglobin levels (<12.5 g/dl [anemic group] vs. 12.5 to 14.5 g/dl [nonanemic group]). The observer-blinded primary end point was the change in absolute pVO2. RESULTS: The difference (95% confidence interval [CI]) in the mean changes from baseline to end of study between the iron and control groups was 273 (151 to 396) ng/ml for ferritin (p < 0.0001), 0.1 (-0.8 to 0.9) g/dl for hemoglobin (p = 0.9), 96 (-12 to 205) ml/min for absolute pVO2 (p = 0.08), 2.2 (0.5 to 4.0) ml/kg/min for pVO2/kg (p = 0.01), 60 (-6 to 126) s for treadmill exercise duration (p = 0.08), -0.6 (-0.9 to -0.2) for New York Heart Association (NYHA) functional class (p = 0.007), and 1.7 (0.7 to 2.6) for patient global assessment (p = 0.002). In anemic patients (n = 18), the difference (95% CI) was 204 (31 to 378) ml/min for absolute pVO2 (p = 0.02), and 3.9 (1.1 to 6.8) ml/kg/min for pVO2/kg (p = 0.01). In nonanemic patients, NYHA functional class improved (p = 0.06). Adverse events were similar. CONCLUSIONS: Intravenous iron loading improved exercise capacity and symptoms in patients with CHF and evidence of abnormal iron metabolism. Benefits were more evident in anemic patients. (Effect of Intravenous Ferrous Sucrose on Exercise Capacity in Chronic Heart Failure; http://www.clinicaltrials.gov/ct/show/NCT00125996; NCT00125996).

Toll-like receptor modulation in cardiovascular disease: a target for intervention?

Toll-like receptors (TLRs) form a family of pattern recognition receptors that have emerged as key mediators of innate immunity. These receptors sense invading microbes and initiate the immune response. TLR-mediated inflammation is an important pathogenic link between innate immunity and a diverse panel of clinical disorders. Among the processes in which TLRs play a role are cardiovascular disorders such as cardiac ischaemia, coronary artery disease, ventricular remodelling, cancer angiogenesis or transplant rejection. From these, many important opportunities for disease modification through TLR signalling manipulation can be imagined. Their role as potential targets for therapeutic intervention is just beginning to be appreciated and this article reviews the current status of these treatment strategies for cardiovascular disease.

Cardiac gene expression of natriuretic substances is altered in streptozotocin-induced diabetes during angiotensin II-induced pressure overload.

OBJECTIVE: To gain insight into the cardiac adaptive mechanisms in diabetes, we studied whether angiotensin II (Ang II) alters expression of the atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP) and adrenomedullin (AM) genes in the left ventricle of the diabetic rat heart. METHODS: Diabetes was induced by streptozotocin (STZ; 60 mg/kg body weight intravenously). During the last 24 h of 2.5 or 7 weeks of treatment of male Wistar rats with STZ or vehicle, Ang II (33 microg/kg per h) was administered via osmotic minipumps. RESULTS: Diabetes was associated with an increased left ventricular weight to body weight (LV/BW) ratio, an index of left ventricular hypertrophy, at week 7 but not at week 2.5, and with increased ANP mRNA content at 2.5 weeks, but not with altered expression of the AM and BNP genes. Mean arterial pressure and LV/BW ratio were increased by Ang II in all groups except in the 7-week diabetic group. Levels of ANP mRNA were increased fourfold (P < 0.001) and threefold (P < 0.05) by Ang II at 2.5 and 7 weeks in control animals, respectively, and 11-fold (P < 0.001) and sevenfold (P < 0.001) at 2.5 and 7 weeks in diabetic animals, respectively. Ang II increased ventricular concentrations of BNP mRNA in control and diabetic animals at 2.5 weeks (1.3-fold, P < 0.001; and 1.6-fold, P < 0.001) and at 7 weeks (1.3-fold, P < 0.05; and 1.8-fold, P < 0.001), respectively. Left ventricular levels of adrenomedullin mRNA were increased by treatment with Ang II for 24 h in 2.5-week diabetic animals. CONCLUSION: Ang II markedly increased the levels of natriuretic peptide mRNAs in the left ventricle of normal and diabetic rat hearts, whereas it increased adrenomedullin mRNA levels only in 2.5-week diabetic rats and failed to cause hypertension in 7-week diabetic rats. Left ventricular levels of ANP and BNP mRNA were increased by Ang II in diabetic animals more than the additive effects of diabetes and Ang II alone, showing that Ang II induced an amplified response with respect to cardiac concentrations of ANP and BNP in diabetes.