Cardiac angiogenic imbalance leads to peripartum cardiomyopathy. Nature. 2012;485:333-338. [PMID: 22596155 PMCID: PMC3356917 DOI: 10.1038/nature11040]

Exposure to experimental preeclampsia in mice enhances the vascular response to future injury

Cardiovascular disease (CVD) remains the leading killer of women in developed nations. One sex-specific risk factor is preeclampsia, a syndrome of hypertension and proteinuria that complicates 5% of pregnancies. Although preeclampsia resolves after delivery, exposed women are at increased long-term risk of premature CVD and mortality. Pre-existing CVD risk factors are associated with increased risk of developing preeclampsia but whether preeclampsia merely uncovers risk or contributes directly to future CVD remains a critical unanswered question. A mouse preeclampsia model was used to test the hypothesis that preeclampsia causes an enhanced vascular response to future vessel injury. A preeclampsia-like state was induced in pregnant CD1 mice by overexpressing soluble fms-like tyrosine kinase-1, a circulating antiangiogenic protein that induces hypertension and glomerular disease resembling human preeclampsia. Two months postpartum, soluble fms-like tyrosine kinase-1 levels and blood pressure normalized and cardiac size and function by echocardiography and renal histology were indistinguishable in preeclampsia-exposed compared with control mice. Mice were then challenged with unilateral carotid injury. Preeclampsia-exposed mice had significantly enhanced vascular remodeling with increased vascular smooth muscle cell proliferation (180% increase; P<0.01) and vessel fibrosis (216% increase; P<0.001) compared with control pregnancy. In the contralateral uninjured vessel, there was no difference in remodeling after exposure to preeclampsia. These data support a new model in which vessels exposed to preeclampsia retain a persistently enhanced vascular response to injury despite resolution of preeclampsia after delivery. This new paradigm may contribute to the substantially increased risk of CVD in woman exposed to preeclampsia.

Update on the pathophysiological implications and clinical role of angiogenic factors in pregnancy

Angiogenic markers are now being incorporated into clinical practice for the screening, diagnosing, and monitoring of preeclampsia. Pregnancy requires both vasculogenesis and angiogenesis in the fetal compartment and angiogenesis in the maternal compartment. Abnormal angiogenesis in the placenta determines impaired remodeling of the maternal spiral arteries and placental underperfusion that may ultimately lead to fetal growth restriction and maternal preeclampsia. The dysregulation of angiogenesis in the placenta and maternal-fetal circulation has emerged as one of the main pathophysiological features in the development of placental insufficiency and its clinical consequences. Abnormal angiogenesis has also been related to other obstetric and fetal conditions such as peripartum cardiomyopathy and fetal cardiac defects. This opens up new challenges for our understanding of angiogenic involvement in maternal cardiovascular function and fetal cardiac development, and it offers new clinical opportunities. This review summarizes the current knowledge of the pathophysiological implications and the clinical role of angiogenic factors in pregnancy.

Peripartum cardiomyopathy: current management and future perspectives

Pregnancy is associated with marked physiological changes challenging the cardiovascular system. Among the more severe pregnancy associated cardiovascular complications, peripartum cardiomyopathy (PPCM) is a potentially life-threatening heart disease emerging towards the end of pregnancy or in the first postpartal months in previously healthy women. A major challenge is to distinguish the peripartum discomforts in healthy women (fatigue, shortness of breath, and oedema) from the pathological symptoms of PPCM. Moreover, pregnancy-related pathologies such as preeclampsia, myocarditis, or underlying genetic disease show overlapping symptoms with PPCM. Difficulties in diagnosis and the discrimination from other pathological conditions in pregnancy may explain why PPCM is still underestimated. Additionally, underlying pathophysiologies are poorly understood, biomarkers are scarce and treatment options in general limited. Experience in long-term prognosis and management including subsequent pregnancies is just beginning to emerge. This review focuses on novel aspects of physiological and pathophysiological changes of the maternal cardiovascular system by comparing normal conditions, hypertensive complications, genetic aspects, and infectious disease in PPCM-pregnancies. It also presents clinical and basic science data on the current state of knowledge on PPCM and brings them in context thereby highlighting promising new insights in diagnostic tools and therapeutic approaches and management.

Peripartum cardiomyopathy and dilated cardiomyopathy: different at heart

Peripartum cardiomyopathy (PPCM) is a severe cardiac disease occurring in the last month of pregnancy or in the first 5 months after delivery and shows many similar clinical characteristics as dilated cardiomyopathy (DCM) such as ventricle dilation and systolic dysfunction. While PPCM was believed to be DCM triggered by pregnancy, more and more studies show important differences between these diseases. While it is likely they share part of their pathogenesis such as increased oxidative stress and an impaired microvasculature, discrepancies seen in disease progression and outcome indicate there must be differences in pathogenesis as well. In this review, we compared studies in DCM and PPCM to search for overlapping and deviating disease etiology, pathogenesis and outcome in order to understand why these cardiomyopathies share similar clinical features but have different underlying pathologies.

The future is now: frontiers on display at Yale-NAVBO cardiovascular inflammation and remodeling symposium 2014

Earlier this year, 200 researchers from across the globe gathered at the Omni New Haven Hotel at Yale University in New Haven, Connecticut, for 3 days of talks from 30 of the leading pioneers in modern cardiovascular medicine. From May 8 to 10, 2014, scientists discussed and dissected topics ranging from the clinical treatment of atherosclerosis to the molecular biology of leukocyte-endothelial cell interactions. With other sessions exploring vascular malformation and aneurysm, hypertension, the endothelial-mesenchymal transition (endo-MT), and the role of metabolism in cardiovascular disease, conference participants gained striking insights into rapid advances and ongoing challenges in the field of cardiovascular inflammation and remodeling.

Accelerated heart function recovery after therapeutic plasma exchange in patient treated with biventricular mechanical circulatory support for severe peripartum cardiomyopathy

We describe a case of severe peripartum cardiomyopathy treated with biventricular mechanical circulatory support, where rapid haemodynamic recovery was observed after therapeutic plasma exchange, used as an adjunct to the inhibition of prolactin release. The patient recovered and after 2 months was discharged from the hospital without clinical symptoms of heart disease.

Peripartum cardiomyopathy: current state of knowledge, new developments and future directions

Peripartum cardiomyopathy (PPCM) is a form of idiopathic dilated cardiomyopathy affecting women in late pregnancy or early puerperium. Although initially described in the late 1800s, it has only recently been recognized as a distinct cardiac condition. The reported incidence and prognosis varies according to geography. The clinical course varies between complete recovery to rapid progression to chronic heart failure, heart transplantation or death. In spite of significant improvements in understanding the pathophysiology and management of the PPCM many features of this unique disease are poorly understood, including incidence, etiology, epidemiology, pathophysiology, predictors of prognosis and optimal therapy. The present article revisits these concepts and recent advances in PPCM.

Discoveries in peripartum cardiomyopathy

The past decade has seen remarkable gains for outcomes in peripartum cardiomyopathy (PPCM), one of the leading causes of maternal mortality and morbidity in the USA and many other countries, including the high-incidence areas of Haiti and South Africa. This review article emphasizes the importance of continuing the process of increasing awareness of PPCM and presents details of this evolving picture, including important discoveries that point the way to full recovery for almost all PPCM subjects. In addition, new interventions will be highlighted, which may facilitate recovery. Numerous studies have demonstrated that when the diagnosis of PPCM is made with LVEF > 0.30, the probability is that recovery to LVEF ≥ 0.50 will occur in the overwhelming majority of subjects. PPCM patients diagnosed with severely depressed systolic function (LVEF < 0.30) and a remodeled left ventricle with greater dilatation (LVEDd ≥ 60mm) are least likely to reach the outcome recovery goals. These are the patients with the greatest need for newer interventional strategies.

VEGF-C and aortic cardiomyocytes guide coronary artery stem development

Coronary arteries (CAs) stem from the aorta at 2 highly stereotyped locations, deviations from which can cause myocardial ischemia and death. CA stems form during embryogenesis when peritruncal blood vessels encircle the cardiac outflow tract and invade the aorta, but the underlying patterning mechanisms are poorly understood. Here, using murine models, we demonstrated that VEGF-C-deficient hearts have severely hypoplastic peritruncal vessels, resulting in delayed and abnormally positioned CA stems. We observed that VEGF-C is widely expressed in the outflow tract, while cardiomyocytes develop specifically within the aorta at stem sites where they surround maturing CAs in both mouse and human hearts. Mice heterozygous for islet 1 (Isl1) exhibited decreased aortic cardiomyocytes and abnormally low CA stems. In hearts with outflow tract rotation defects, misplaced stems were associated with shifted aortic cardiomyocytes, and myocardium induced ectopic connections with the pulmonary artery in culture. These data support a model in which CA stem development first requires VEGF-C to stimulate vessel growth around the outflow tract. Then, aortic cardiomyocytes facilitate interactions between peritruncal vessels and the aorta. Derangement of either step can lead to mispatterned CA stems. Studying this niche for cardiomyocyte development, and its relationship with CAs, has the potential to identify methods for stimulating vascular regrowth as a treatment for cardiovascular disease.

Sirtuin 1 ablation in endothelial cells is associated with impaired angiogenesis and diastolic dysfunction

Discordant myocardial growth and angiogenesis can explain left ventricular (LV) hypertrophy progressing toward heart failure with aging. Sirtuin 1 expression declines with age; therefore we explored the role played by angiogenesis and Sirtuin 1 in the development of cardiomyopathy. We compared the cardiac function of 10- to 15-wk-old (wo), 30-40 wo, and 61-70 wo endothelial Sirtuin 1-deleted (Sirt1(endo-/-)) mice and their corresponding knockout controls (Sirt1(Flox/Flox)). After 30-40 wk, Sirt1(endo-/-) animals exhibited diastolic dysfunction (DD), decreased mRNA expression of Serca2a in the LV, and decreased capillary density compared with control animals despite a similar VEGFa mRNA expression. However, LV fibrosis and hypoxia-inducible factor (HIF)1α expression were not different. The creation of a transverse aortic constriction (TAC) provoked more severe DD and LV fibrosis in Sirt1(endo-/-) compared with control TAC animals. Although the VEGFa mRNA expression was not different and the protein expression of HIF1α was higher in the Sirt1(endo-/-) TAC animals, capillary density remained reduced. In cultured endothelial cells administration of Sirtuin 1 inhibitor decreased mRNA expression of VEGF receptors FLT 1 and FLK 1. Ex vivo capillary sprouting from aortic explants showed impaired angiogenic response to VEGF in the Sirt1(endo-/-) mice. In conclusion, the data demonstrate 1) a defect in angiogenesis preceding development of DD; 2) dispensability of endothelial Sirtuin 1 under unstressed conditions and during normal aging; and 3) impaired angiogenic adaptation and aggravated DD in Sirt1(endo-/-) mice challenged with LV overload.

Peripartum cardiomyopathy: Euro Observational Research Program

Peripartum cardiomyopathy is a rare but potentially life-threatening form of heart failure affecting women late in pregnancy or in the first months after delivery. Peripartum cardiomyopathy is difficult to diagnose and its onset and progression are variable between individuals. The pathophysiology remains poorly understood, hence treatment options are limited and possibly harmful to the foetus. Furthermore, geographical incidence varies greatly and little is known about the incidence in Western countries. To gain further understanding of the pathophysiology and incidence of peripartum cardiomyopathy, the European Society of Cardiology initiated a study group to implement a registry. This review provides an overview of current insights into peripartum cardiomyopathy, highlights the need for such a registry and provides information about this Euro Observational Research Program.

Promoting PGC-1α-driven mitochondrial biogenesis is detrimental in pressure-overloaded mouse hearts

Mitochondrial dysfunction in animal models of heart failure is associated with downregulation of the peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α pathway. To test whether PGC-1α is an appropriate therapeutic target for increasing mitochondrial biogenesis and improving function in heart failure, we used a transgenic (TG) mouse model of moderate overexpression of PGC-1α (∼3-fold) in the heart. TG mice had small increases in citrate synthase activity and mitochondria size in the heart without alterations in myocardial energetics or cardiac function at baseline. In vivo dobutamine stress increased fractional shortening in wild-type mice, but this increase was attenuated in TG mice, whereas ex vivo isolated perfused TG hearts demonstrated normal functional and energetic response to high workload challenge. When subjected to pressure overload by transverse aortic constriction (TAC), TG mice displayed a significantly greater acute mortality for both male and female mice; however, long-term survival up to 8 wk was similar between the two groups. TG mice also showed a greater decrease in fractional shortening and a greater increase in left ventricular chamber dimension in response to TAC. Mitochondrial gene expression and citrate synthase activity were mildly increased in TG mice compared with wild-type mice, and this difference was also maintained after TAC. Our data suggest that a moderate level of PGC-1α overexpression in the heart compromises acute survival and does not improve cardiac function during chronic pressure overload in mice.

Leukocyte driven-decidual angiogenesis in early pregnancy

Successful pregnancy and long-term, post-natal maternal and offspring cardiac, vascular and metabolic health require key maternal cardiovascular adaptations over gestation. Within the pregnant decidualizing uterus, coordinated vascular, immunological and stromal cell changes occur. Considerable attention has been given to the roles of uterine natural killer (uNK) cells in initiating decidual spiral arterial remodeling, a process normally completed by mid-gestation in mice and in humans. However, leukocyte roles in much earlier, region specific, decidual vascular remodeling are now being defined. Interest in immune cell-promoted vascular remodeling is driven by vascular aberrations that are reported in human gestational complications such as infertility, recurrent spontaneous abortion, preeclampsia (PE) and fetal growth restriction. Appropriate maternal cardiovascular responses during pregnancy protect mothers and their children from later cardiovascular disease risk elevation. One of the earliest uterine responses to pregnancy in species with hemochorial placentation is stromal cell decidualization, which creates unique niches for angiogenesis and leukocyte recruitment. In early decidua basalis, the aspect of the implantation site that will cradle the developing placenta and provide the major blood vessels to support mature placental functions, leukocytes are greatly enriched and display specialized properties. UNK cells, the most abundant leukocyte subset in early decidua basalis, have angiogenic abilities and are essential for normal early decidual angiogenesis. The regulation of uNK cells and their roles in determining maternal and progeny cardiovascular health over pregnancy and postpartum are discussed.

Earlier detection can help avoid many serious complications of peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) has a remarkable potential for recovery. It may be within our capability to help almost all women with PPCM not only to survive, but also to completely recover heart function. Time-of-diagnosis left ventricular ejection fraction (LVEF) ≥0.35 is associated with better survival rates and higher full recovery rates. Increased mortality, chronic cardiomyopathy, thromboembolic complications and serious ventricular tachyarrhythmias are associated with diagnostic LVEF <0.30. Delays in diagnosis may result in lower LVEF at diagnosis and subsequent lower recovery rates. Greater awareness of the possibility of heart failure developing in previously healthy young women, with no history of heart disease, will contribute to earlier diagnosis, with potentially better preserved heart function. Women of African descent may be at higher risk for poorer outcomes. Recent investigations suggest newer biomarkers may help with earlier detection of PPCM.

Vascular Endothelial Growth Factor-B in Physiology and Disease

Vascular endothelial growth factor-B (VEGF-B), discovered over 15 years ago, has long been seen as one of the more ambiguous members of the VEGF family. VEGF-B is produced as two isoforms: one that binds strongly to heparan sulfate in the pericellular matrix and a soluble form that can acquire binding via proteolytic processing. Both forms of VEGF-B bind to VEGF-receptor 1 (VEGFR-1) and the neuropilin-1 (NRP-1) coreceptor, which are expressed mainly in blood vascular endothelial cells. VEGF-B-deficient mice and rats are viable without any overt phenotype, and the ability of VEGF-B to induce angiogenesis in most tissues is weak. This has been a puzzle, as the related placenta growth factor (PlGF) binds to the same receptors and induces angiogenesis and arteriogenesis in a variety of tissues. However, it seems that VEGF-B is a vascular growth factor that is more tissue specific and can have trophic and metabolic effects, and its binding to VEGFR-1 shows subtle but important differences compared with that of PlGF. VEGF-B has the potential to induce coronary vessel growth and cardiac hypertrophy, which can protect the heart from ischemic damage as well as heart failure. In addition, VEGF-B is abundantly expressed in tissues with highly active energy metabolism, where it could support significant metabolic functions. VEGF-B also has a role in neuroprotection, but unlike other members of the VEGF family, it does not have a clear role in tumor progression. Here we review what is hitherto known about the functions of this growth factor in physiology and disease.

Scalable Collaborative Infrastructure for a Learning Healthcare System (SCILHS): architecture

We describe the architecture of the Patient Centered Outcomes Research Institute (PCORI) funded Scalable Collaborative Infrastructure for a Learning Healthcare System (SCILHS, http://www.SCILHS.org) clinical data research network, which leverages the $48 billion dollar federal investment in health information technology (IT) to enable a queryable semantic data model across 10 health systems covering more than 8 million patients, plugging universally into the point of care, generating evidence and discovery, and thereby enabling clinician and patient participation in research during the patient encounter. Central to the success of SCILHS is development of innovative 'apps' to improve PCOR research methods and capacitate point of care functions such as consent, enrollment, randomization, and outreach for patient-reported outcomes. SCILHS adapts and extends an existing national research network formed on an advanced IT infrastructure built with open source, free, modular components.

Biomarker predictors of cardiac hospitalization in chronic heart failure: a recurrent event analysis

BACKGROUND

Identification of heart failure (HF) patients at risk for hospitalization may improve care and reduce costs. We evaluated 9 biomarkers as predictors of cardiac hospitalization in chronic HF.

METHODS AND RESULTS

In a multicenter cohort of 1,512 chronic HF outpatients, we assessed the association between 9 biomarkers and cardiac hospitalization with the use of a recurrent events approach. Over a median follow-up of 4 years, 843 participants experienced ≥ 1 hospitalizations (total 2,178 hospitalizations). B-type natriuretic peptide (BNP) and troponin I (TnI) exhibited the strongest associations with risk of hospitalization (hazard ratio [HR] 3.8 [95% confidence interval (CI) 2.9-4.9] and HR 3.3 [95% CI 2.8-3.9]; 3rd vs 1st tertiles). Soluble Fms-like tyrosine kinase receptor 1 (sFlt-1) exhibited the next strongest association (HR 2.8 [95% CI 2.4-3.4]), followed by soluble Toll-like receptor 2 (HR 2.3 [95% CI 2.0-2.8]) and creatinine (HR 1.9 [95% CI 1.6-2.4]). Within ischemic/nonischemic subgroups, BNP and TnI remained most strongly associated. Except for creatinine, HRs for all biomarkers studied were smaller within the ischemic subgroup, suggesting greater importance of cardiorenal interactions in decompensation of ischemic HF.

CONCLUSION

Although BNP and TnI exhibited the strongest associations with hospitalization, etiology-dependent associations for the remaining biomarkers suggest etiology-specific mechanisms for HF exacerbation. sFlt-1 exhibited a strong association with cardiac hospitalization, highlighting its potential role as a biomarker of HF morbidity.

An update on treatments and outcomes in peripartum cardiomyopathy

ABSTRACT: 

Peripartum cardiomyopathy (PPCM) is a well-established complication of pregnancy. Criteria include heart failure that presents with reduced left ventricular function, signs and symptoms of heart failure either late in pregnancy or early in the postpartum period. The incidence varies widely depending geography and ethnicity. The pathophysiology of PPCM is still an area of active investigation, but includes immune and inflammatory mechanisms, which are the subject of several investigations. Therapies for chronic heart failure from PPCM are similar to those patients with nonischemic cardiomyopathy from different etiologies, however novel therapies may include bromocriptine, pentoxifylline or other potential therapies influencing the immune system. The need for implantable defibrillators, left ventricular assist devices and cardiac transplant in women with PPCM is rare, and prognosis is better than other forms of nonischemic cardiomyopathy. Despite this, further information about the epidemiology, prognosis and potential therapies are required to better manage and diagnose PPCM in women with signs and symptoms of heart failure.

Maintaining PGC-1α expression following pressure overload-induced cardiac hypertrophy preserves angiogenesis but not contractile or mitochondrial function

During pathological hypertrophy, peroxisome proliferator-activated receptor coactivator 1α (PGC-1α) is repressed in concert with reduced mitochondrial oxidative capacity and fatty acid oxidation (FAO). We therefore sought to determine if maintaining or increasing PGC-1α levels in the context of pressure overload hypertrophy (POH) would preserve mitochondrial function and prevent contractile dysfunction. Pathological cardiac hypertrophy was induced using 4 wk of transverse aortic constriction (TAC) in mice overexpressing the human PGC-1α genomic locus via a bacterial artificial chromosome (TG) and nontransgenic controls (Cont). PGC-1α levels were increased by 40% in TG mice and were sustained following TAC. Although TAC-induced repression of FAO genes and oxidative phosphorylation (oxphos) genes was prevented in TG mice, mitochondrial function and ATP synthesis were equivalently impaired in Cont and TG mice after TAC. Contractile function was also equally impaired in Cont and TG mice following TAC, as demonstrated by decreased +dP/dt and ejection fraction and increased left ventricular developed pressure and end diastolic pressure. Conversely, capillary density was preserved, in concert with increased VEGF expression, while apoptosis and fibrosis were reduced in TG relative to Cont mice after TAC. Hence, sustaining physiological levels of PGC-1α expression following POH, while preserving myocardial vascularity, does not prevent mitochondrial and contractile dysfunction.

Peripartum cardiomyopathy: update 2012

PURPOSE OF REVIEW

Peripartum cardiomyopathy (PPCM) is a disorder in which initial left ventricular systolic dysfunction and symptoms of heart failure occur between the late stages of pregnancy and the early postpartum period. Incidences vary geographically; it is common in some countries and rare in others. The acute form of PPCM is a clinical syndrome with reduced cardiac output, tissue hypoperfusion, and increase in the pulmonary capillary wedge pressure. Monitoring of the patient with the acute form of PPCM should be initiated as soon as possible. The syndrome carries a high morbidity and mortality and diagnosis is often delayed. This review focuses on new data and aspects in terms of diagnosis, causes of disease, pharmacological therapy, and management of delivery in patients with PPCM.

RECENT FINDINGS

New investigations reveal that PPCM is likely due to multiple factors. It develops based on oxidative stress leading to cleavage of deleterious 16-kDa prolactin, which can be blocked with bromocriptine. New data show furthermore that it is partly a two-hit vascular disease due to imbalances in angiogenic signaling worsening the severity of the disease.

SUMMARY

Different mechanisms have been investigated and give rise to promising therapeutic approach, which will be developed based on the new findings.

The many roles of PGC-1α in muscle--recent developments

Skeletal muscle is the largest organ in the body and contributes to innumerable aspects of organismal biology. Muscle dysfunction engenders numerous diseases, including diabetes, cachexia, and sarcopenia. At the same time, skeletal muscle is also the main engine of exercise, one of the most efficacious interventions for prevention and treatment of a wide variety of diseases. The transcriptional coactivator PGC-1α has emerged as a key driver of metabolic programming in skeletal muscle, both in health and in disease. We review here the many aspects of PGC-1α function in skeletal muscle, with a focus on recent developments.

Peripartum cardiomyopathy: A puzzle closer to solution

Peripartum cardiomyopathy (PPCM) represents new heart failure in a previously heart-healthy peripartum patient. It is necessary to rule out all other known causes of heart failure before accepting a diagnosis of PPCM. The modern era for PPCM in the United States and beyond began with the report of the National Institutes of Health PPCM Workshop in 2000, clarifying all then-currently known aspects of the disease. Since then, hundreds of publications have appeared, an indication of how devastating this disease can be to young mothers and their families and the urgent desire to find solutions for its cause and better treatment. The purpose of this review is to highlight the important advances that have brought us nearer to the solution of this puzzle, focusing on what we have learned about PPCM since 2000; and what still remains unanswered. Despite many improvements in outcome, we still do not know the actual triggers that initiate the pathological process; but realize that cardiac angiogenic imbalances resulting from complex pregnancy-related immune system and hormonal changes play a key role.

Pregnancy as a cardiac stress model

Cardiac hypertrophy occurs during pregnancy as a consequence of both volume overload and hormonal changes. Both pregnancy- and exercise-induced cardiac hypertrophy are generally thought to be similar and physiological. Despite the fact that there are shared transcriptional responses in both forms of cardiac adaptation, pregnancy results in a distinct signature of gene expression in the heart. In some cases, however, pregnancy can induce adverse cardiac events in previously healthy women without any known cardiovascular disease. Peripartum cardiomyopathy is the leading cause of non-obstetric mortality during pregnancy. To understand how pregnancy can cause heart disease, it is first important to understand cardiac adaptation during normal pregnancy. This review provides an overview of the cardiac consequences of pregnancy, including haemodynamic, functional, structural, and morphological adaptations, as well as molecular phenotypes. In addition, this review describes the signalling pathways responsible for pregnancy-induced cardiac hypertrophy and angiogenesis. We also compare and contrast cardiac adaptation in response to disease, exercise, and pregnancy. The comparisons of these settings of cardiac hypertrophy provide insight into pregnancy-associated cardiac adaptation.

Management of cardiovascular diseases during pregnancy

The prevalence of cardiovascular diseases (CVDs) in women of childbearing age is rising. The successes in medical and surgical treatment of congenital heart disease have led to an increasing number of women at childbearing age presenting with problems of treated congenital heart disease. Furthermore, in developing countries and in immigrants from these countries, rheumatic valvular heart disease still plays a significant role in young women. Increasing age of pregnant women and increasing prevalence of atherosclerotic risk factors have led to an increase in women with coronary artery disease at pregnancy. Successful management of pregnancy in women with CVDs requires early diagnosis, a thorough risk stratification, and appropriate management by a multidisciplinary team of obstetricians, cardiologists, anesthesiologists, and primary care physicians. The following review is based on the recent European guidelines on the management of CVDs during pregnancy, which aim at providing concise and simple recommendations for these challenging problems.

STAT3, a key regulator of cell-to-cell communication in the heart

The signal transducer and activator of transcription 3 (STAT3) is fundamental for physiological homeostasis and stress-induced remodelling of the heart as deregulated STAT3 circuits are sufficient to induce dilated and peripartum cardiomyopathy and adverse remodelling after myocardial infarction. STAT3 activity depends on multiple post-translational modifications (phosphorylation, acetylation, and dimerization). It is regulated by multiple receptor systems, which are coupled to positive and negative feedback loops to ensure physiological and beneficial action. Its intracellular functions are diverse as it acts as a signalling protein, a transcription factor but also participates in mitochondria energy production and protection. STAT3 modulates proliferation, differentiation, survival, oxidative stress, and/or metabolism in cardiomyocytes, fibroblasts, endothelial cells, progenitor cells, and various inflammatory cells. By regulating the secretome of these cardiac cells, STAT3 influences a broad range of intercellular communication systems. It thereby impacts on the communication between cardiomyocytes, the plasticity of the cardiac microenvironment, the vasculature, the extracellular matrix, and the inflammation in response to physiological and pathophysiological stress. Here, we sum up current knowledge on STAT3-mediated intra- and intercellular communication within the heterogeneous cellular network of the myocardium to co-ordinate complex biological processes and discuss STAT3-dependent targets as novel therapeutic concepts to treat various forms of heart disease.

Hypoxic induction of vascular endothelial growth factor (VEGF) and angiogenesis in muscle by truncated peroxisome proliferator-activated receptor γ coactivator (PGC)-1α

The transcriptional coactivator peroxisome proliferator-activator receptor γ coactivator (PGC)-1α is required for full hypoxic induction of vascular endothelial growth factor (VEGF) in skeletal muscle cells. Under normoxic conditions, PGC-1α also strongly induces mitochondrial biogenesis, but PGC-1α does not activate this program under hypoxic conditions. How this specificity is achieved is not known. We show here that hypoxia specifically induces alternatively spliced species encoding for truncated forms of PGC-1α: NT-PGC-1α and PGC-1α4. NT-PGC-1α strongly induces VEGF expression, whereas having little effect on mitochondrial genes. Conditioned medium from cells expressing NT-PGC-1α robustly induces endothelial migration and tube formation, hallmarks of angiogenesis. Transgenic expression of PGC-1α4 in skeletal muscle in mice induces angiogenesis in vivo. Finally, knockdown of these PGC-1α isoforms and hypoxia-inducible factor-1α (HIF-1α) abrogates the induction of VEGF in response to hypoxia. NT-PGC-1α and/or PGC-1α4 thus confer angiogenic specificity to the PGC-1α-mediated hypoxic response in skeletal muscle cells.

Endothelial PGC-1α mediates vascular dysfunction in diabetes

Endothelial dysfunction is a central hallmark of diabetes. The transcriptional coactivator PGC-1α is a powerful regulator of metabolism, but its role in endothelial cells remains poorly understood. We show here that endothelial PGC-1α expression is high in diabetic rodents and humans and that PGC-1α powerfully blocks endothelial migration in cell culture and vasculogenesis in vivo. Mechanistically, PGC-1α induces Notch signaling, blunts activation of Rac/Akt/eNOS signaling, and renders endothelial cells unresponsive to established angiogenic factors. Transgenic overexpression of PGC-1α in the endothelium mimics multiple diabetic phenotypes, including aberrant re-endothelialization after carotid injury, blunted wound healing, and reduced blood flow recovery after hindlimb ischemia. Conversely, deletion of endothelial PGC-1α rescues the blunted wound healing and recovery from hindlimb ischemia seen in type 1 and type 2 diabetes. Endothelial PGC-1α thus potently inhibits endothelial function and angiogenesis, and induction of endothelial PGC-1α contributes to multiple aspects of vascular dysfunction in diabetes.

Glutaredoxin-1 up-regulation induces soluble vascular endothelial growth factor receptor 1, attenuating post-ischemia limb revascularization

Glutaredoxin-1 (Glrx) is a cytosolic enzyme that regulates diverse cellular function by removal of GSH adducts from S-glutathionylated proteins including signaling molecules and transcription factors. Glrx is up-regulated during inflammation and diabetes, and Glrx overexpression inhibits VEGF-induced EC migration. The aim was to investigate the role of up-regulated Glrx in EC angiogenic capacities and in vivo revascularization in the setting of hind limb ischemia. Glrx-overexpressing EC from Glrx transgenic (TG) mice showed impaired migration and network formation and secreted higher levels of soluble VEGF receptor 1 (sFlt), an antagonizing factor to VEGF. After hind limb ischemia surgery Glrx TG mice demonstrated impaired blood flow recovery, associated with lower capillary density and poorer limb motor function compared with wild type littermates. There were also higher levels of anti-angiogenic sFlt expression in the muscle and plasma of Glrx TG mice after surgery. Noncanonical Wnt5a is known to induce sFlt. Wnt5a was highly expressed in ischemic muscles and EC from Glrx TG mice, and exogenous Wnt5a induced sFlt expression and inhibited network formation in human microvascular EC. Adenoviral Glrx-induced sFlt in EC was inhibited by a competitive Wnt5a inhibitor. Furthermore, Glrx overexpression removed GSH adducts on p65 in ischemic muscle and EC and enhanced NF-κB activity, which was responsible for Wnt5a-sFlt induction. Taken together, up-regulated Glrx induces sFlt in EC via NF-κB-dependent Wnt5a, resulting in attenuated revascularization in hind limb ischemia. The Glrx-induced sFlt explains part of the mechanism of redox-regulated VEGF signaling.

The correlation between peripartum cardiomyopathy and autoantibodies against cardiovascular receptors

Background

Peripartum cardiomyopathy (PPCM) is characterized by left ventricular systolic dysfunction and heart failure. However, its pathogenesis is not clear. Our preliminary study revealed that autoantibodies against β₁-adrenergic receptors (β₁R-AABs) and M₂-muscarinic receptors (M₂R-AABs) participated in heart failure regardless of primary heart disease. Whether β₁R-AABs and M₂R-AABs participate in the pathogenesis of PPCM is still unknown.

Methods

Totally 37 diagnosed PPCM patients and 36 normal pregnant women were enrolled in this study. Clinical assessment and 2-dimensional echocardiographic studies as well as the measurement of β₁R-AABs or M₂R-AABs by enzyme linked immunosorbent assay (ELISA) were performed.

Results

The positive rates for β₁R-AABs and M₂R-AABs were 59.5% (22/37) and 45.9% (17/37) in PPCM patients, and 19.4% (7/36) (P<0.001) and 16.67% (6/36) (P<0.001) in normal pregnant women, respectively. Both β₁R-AABs and M₂R-AABs had a positive correlation with serum expression level of NT-proBNP, left ventricular dimension and NYHA FC (rs: 0.496–0.892, P<0.01). In addition, a negative correlation between the activity of β₁R-AABs and M₂R-AABs and LVEF, LVFS was observed (rs: −0.488–0.568, P<0.01). Moreover, autoantibodies against cardiovascular receptors increased the risk of the onset of PPCM (OR = 18.786, 95% confidence interval 1.926–183.262, P = 0.012).

Conclusions

The β₁R-AABs and M₂R-AABs reveal a significant elevation and are correlated with the increased left ventricular dimension and worse cardiac contraction function. The autoantibodies of cardiovascular receptors are independent risk factors for the onset of PPCM.

Pregnancy, cardiomyopathies, and genetics

Although familial forms of cardiomyopathy such as hypertrophic or dilated cardiomyopathy have been recognized for decades, it is only recently that much of the genetic basis of these inherited cardiomyopathies has been elucidated. This has provided important insights into the pathophysiological mechanisms underlying the disease phenotype. This increased knowledge and the availability of genetic testing has resulted in increasing numbers of mutation carriers who are being monitored, including many who are now of child-bearing age. Pregnancy is generally well tolerated in asymptomatic patients or mutation carriers with inherited cardiomyopathies. However, since pregnancy leads to major physiological changes in the cardiovascular system, in women with genetic cardiomyopathies or who carry a mutation pre-disposing to a genetic cardiomyopathy, pregnancy entails a risk of developing heart failure and/or arrhythmias. This deterioration of cardiac function may occur despite optimal medical treatment. Advanced left ventricular dysfunction, poor functional class (NYHA class III or IV), or prior cardiac events appear to increase the risk of maternal cardiac complications. However, there are no large series of cardiomyopathy patients who are regularly evaluated for cardiac complications during pregnancy and for certain types of inherited cardiomyopathy, only case reports on individual pregnancies are available. Pre-conception cardiologic evaluation and genetic counselling are important for every woman with a cardiomyopathy or a cardiomyopathy-related mutation who is considering having a family. In this article, we give an overview of the basic clinical aspects, genetics, and pregnancy outcome in women with different types of inherited cardiomyopathies. We also discuss the genetic aspects of pregnancy-associated cardiomyopathy, including peripartum cardiomyopathy.

Differences in clinical profile of African-American women with peripartum cardiomyopathy in the United States

BACKGROUND

Peripartum cardiomyopathy (PPCM) is a rare and heterogeneous disease with a higher prevalence in African Americans (AAs) in the USA. The clinical features and prognosis of PPCM in AAs have not been sufficiently characterized.

METHODS

We studied 52 AA patients with PPCM and compared clinical characteristics and outcome with those of 104 white patients.

RESULTS

AA patients were significantly younger (26 ± 7 vs 30 ± 6 years; P < .001), had a higher prevalence of gestational hypertension (61% vs 41%; P = .03), and were diagnosed more commonly postpartum rather then antepartum (83% vs 64%; P = .03). The rate of left ventricular (LV) recovery (LV ejection fraction [LVEF] ≥50%) was significantly lower in AAs (40% vs 61%; P = .02). AA women also had a larger LV end-diastolic diameter (57 ± 10 vs 51 ± 6 mm; P = .004) as well as lower LVEF (40% ± 16.7% vs 46% ± 14%; P = .002) at the last follow-up. Moreover, AA patients had a significantly higher incidence of the combined end points of mortality and cardiac transplantation (P = .03) and showed a strong trend (P = .09) for increased mortality.

CONCLUSIONS

AA patients with PPCM in the USA have a different clinical profile and worse prognosis compared with white patients. Further research to evaluate potentially correctable causes for these differences is warranted.

Opposing roles of Akt and STAT3 in the protection of the maternal heart from peripartum stress

BACKGROUND

Peripartum cardiomyopathy (PPCM) is a pregnancy-associated cardiomyopathy in previously healthy women. Mice with a cardiomyocyte-restricted deletion of signal transducer and activator of transcription-3 (STAT3, CKO) develop PPCM. PI3K-Akt signalling is thought to promote cardiac hypertrophy and protection during pregnancy. We evaluated the role of activated Akt signalling in the maternal heart postpartum.

METHODS AND RESULTS

CKO mice were bred to mice harbouring an Akt transgene, specifically expressed in cardiomyocytes (CAkt(tg)) generating CKO; CAkt(tg), CAkt(tg), CKO, and wild-type sibling mice. CAkt(tg) and CKO;CAkt(tg) female mice developed PPCM with systolic dysfunction. Both genotypes displayed cardiac hypertrophy and lower capillary density, showed increased phosphorylation of p66 Src homology 2 domain containing protein and FoxO3A, and reduced expression of manganese superoxide dismutase as well as increased cathepsin D activity and increased miR-146a levels [indicative for generation of the anti-angiogenic 16 kDa prolactin (PRL)]. Cardiac inflammation and fibrosis was accelerated in CKO;CAkt(tg) and associated with high postpartum mortality. The PRL blocker, bromocriptine (BR), prevented heart failure and the decrease in capillary density in CKO;CAkt(tg) and CAkt(tg) mice. BR attenuated high mortality, up-regulation of CCL2, and cardiac inflammation as well as fibrosis in CKO;CAkt(tg). PRL infusion induced cardiac inflammation in CKO;CAkt(tg) independent of pregnancy. In neonatal rat cardiomyocytes, PRL and interferon γ (IFNγ) induced the expression of CCL2 via activation of Akt.

CONCLUSION

Postpartum Akt activation is detrimental for the peripartum heart as it lowers anti-oxidative defence and in combination with low STAT3 conditions, accelerate cardiac inflammation and fibrosis. PRL and its cleaved 16 kDa form are central for Akt-induced PPCM as indicated by the protection from the disease by PRL blockade.

Maternal cardiac metabolism in pregnancy

Pregnancy causes dramatic physiological changes in the expectant mother. The placenta, mostly foetal in origin, invades maternal uterine tissue early in pregnancy and unleashes a barrage of hormones and other factors. This foetal 'invasion' profoundly reprogrammes maternal physiology, affecting nearly every organ, including the heart and its metabolism. We briefly review here maternal systemic metabolic changes during pregnancy and cardiac metabolism in general. We then discuss changes in cardiac haemodynamic during pregnancy and review what is known about maternal cardiac metabolism during pregnancy. Lastly, we discuss cardiac diseases during pregnancy, including peripartum cardiomyopathy, and the potential contribution of aberrant cardiac metabolism to disease aetiology.

Calcineurin activity is required for cardiac remodelling in pregnancy

AIMS

Calcium fluctuations and cardiac hypertrophy occur during pregnancy, but the role of the well-studied calcium-activated phosphatase, calcineurin, has not been studied in this setting. The purpose of this study was to determine whether calcineurin signalling is required for cardiac remodelling during pregnancy in mice.

METHODS AND RESULTS

We first examined calcineurin expression in the heart of mice during pregnancy. We found both calcineurin levels and activity were significantly increased in early-pregnancy and decreased in late-pregnancy. Since progesterone levels start to rise in early-pregnancy, we investigated whether progesterone alone was sufficient to modulate calcineurin levels in vivo. After implantation of progesterone pellets in non-pregnant female mice, cardiac mass increased, whereas cardiac function was maintained. In addition, calcineurin levels increased, which is also consistent with early-pregnancy. To determine whether these effects were occurring in the cardiac myocytes, we treated neonatal rat ventricular myocytes (NRVMs) with pregnancy-associated sex hormones. We found that progesterone treatment, but not oestradiol, increased calcineurin levels. To obtain a functional read-out of increased calcineurin activity, we measured the activity of the transcription factor NFAT, a downstream target of calcineurin. Progesterone treatment significantly increased NFAT activity in NRVMs, and this was blocked by the calcineurin inhibitor cyclosporine A (CsA), showing that the progesterone-mediated increase in NFAT activity requires calcineurin activity. Importantly, CsA treatment of mice completely blocked pregnancy-induced cardiac hypertrophy.

CONCLUSION

Our results show that calcineurin is required for pregnancy-induced cardiac hypertrophy, and that calcineurin activity in early-pregnancy is due at least in part to increased progesterone.

The relationship between pre-eclampsia and peripartum cardiomyopathy: a systematic review and meta-analysis

OBJECTIVES

The goal of this study was to systematically review the peripartum cardiomyopathy (PPCM) literature and determine the prevalence of pre-eclampsia (PE) in women with PPCM. Secondary analyses included evaluation of the prevalence of hypertensive disorders, multiple gestations, and multiparity.

BACKGROUND

PPCM is a significant cause of maternal and infant morbidity and mortality worldwide, yet its etiology remains unknown. PE is often cited as a risk factor for the development of PPCM and recent research suggests that PE and PPCM share mechanisms that contribute to their pathobiology. No comprehensive evaluation of the relationship between PE and PPCM exists.

METHODS

A systematic predetermined search strategy was performed in multiple databases to identify studies describing ≥3 women with PPCM. Prevalence rates of PE, hypertension, multiple gestations, and multiparity were pooled.

RESULTS

Data from 22 studies (n = 979) were included in this analysis. The pooled prevalence of 22% (95% confidence interval [CI]: 16% to 28%) was more than quadruple the 5% average worldwide background rate of PE in pregnancy (p < 0.001). There were no geographic or racial differences detected in the prevalence of PE in women with PPCM. The rates of hypertension during pregnancy (37% [95% CI: 29% to 45%]) and multiple gestations (9% [95% CI: 7% to 11%]) were also elevated.

CONCLUSIONS

The prevalence of PE, hypertensive disorders, and multiple gestations in women with PPCM is markedly higher than that in the general population. These findings support the concept of a shared pathogenesis between PE and PPCM and highlight the need for awareness of the overlap between these 2 diseases.