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Cardiolipin is a specific mitochondrial phospholipid that has a high affinity for proteins and that stabilizes the assembly of supercomplexes involved in oxidative phosphorylation. We found that sequestration of cardiolipin in protein complexes is critical to protect it from degradation. The turnover of cardiolipin is slower by almost an order of magnitude than the turnover of other phospholipids. However, in Barth syndrome, cardiolipin is rapidly degraded via the intermediate monolyso-cardiolipin. Treatments that induce supercomplex assembly decrease the turnover of cardiolipin and the concentration of monolyso-cardiolipin whereas dissociation of supercomplexes has the opposite effect. Our data suggest that cardiolipin is uniquely protected from normal lipid turnover by its association with proteins, but in Barth syndrome, where this association is compromised, cardiolipin becomes unstable, which causes the accumulation of monolyso-cardiolipin.

When cardiac function and blood flow are first established are fundamental questions in mammalian embryogenesis. The earliest erythroblasts arise in yolk sac blood islands and subsequently enter the embryo proper to initiate circulation. Embryos staged 0 to 30 somites (S) were examined in utero with 40-to 50-MHz ultrasound biomicroscopy (UBM)-Doppler, to determine onset of embryonic heartbeat and blood flow and to characterize basic physiology of the very early mouse embryonic circulation. A heartbeat was first detected at 5 S, and blood vascular flow at 7 S. Heart rate, peak arterial velocity, and velocity-time integral showed progressive increases that indicated a dramatically increasing cardiac output from even the earliest stages. In situ hybridization revealed an onset of the heartbeat coincident with the appearance of yolk sac-derived erythroblasts in the embryo proper at 5 S. Early maturation of the circulation follows a tightly coordinated program.T he heart is the first organ to develop during embryogenesis. However, little is known about the fundamental questions of when cardiac function and blood flow are first established. Data have come largely from invasive methods 1,2 that disrupt the normal physiological milieu, and scant data exist in the mouse, the primary model of mammalian development. 2,3 Functional circulation is composed of the beating heart, vascular bed, and blood cells. The yolk sac is the earliest and only source of hematopoietic progenitors in the gastrulating mouse embryo. 4 Primitive erythroid progenitors originate in the yolk sac beginning at the late primitive streak stage, before the establishment of circulation in the embryo proper. 4,5 These progenitors give rise to maturing primitive erythroblasts within yolk sac blood islands, which then enter the embryo proper to initiate circulation.We hypothesized that the timing of onset of heartbeat and erythroid cell migration are tightly coordinated. We sought therefore to characterize time points and basic physiology of the very early mouse embryonic circulation using ultrasound biomicroscopy (UBM)-Doppler, a high-frequency echocardiography system developed in our laboratory that allows in utero study of the embryonic mouse circulation. 6 -9 Materials and MethodsThe imaging and whole-mount in situ hybridization protocols have been reported elsewhere, with minor modifications to study earlystage embryos. UBM-Doppler imaging was performed using a semi-invasive in utero approach, exteriorizing the uterus but otherwise maintaining all circulatory systems intact, in close-to-physiological conditions (see the online data supplement available at http://www.circresaha.org for an expanded Materials and Methods section). Results UBM-Doppler Imaging of Early-Stage EmbryosDespite the need for maternal anesthesia, our results indicate that semi-invasive UBM-Doppler yields physiologically relevant data and is uniquely suited to study early embryonic cardiovascular function (see the online data supplement for additional Results). Initiation of Early...

Objective The recurrence rate of anti-SSA/Ro associated congenital heart block (CHB) is 17%. Reversal of 3rd degree block has never been achieved. Based on potential reduction of maternal autoantibody titers as well as fetal inflammatory responses, IVIG was evaluated as a preventative therapy for CHB. Methods A multicenter open-label study based on Simon’s 2-stage optimal design was initiated. Enrollment criteria included: maternal anti-SSA/Ro antibody, a previous child with CHB/rash,

Background-Ebstein anomaly and tricuspid valve dysplasia are rare congenital tricuspid valve malformations associated with high perinatal mortality. The literature consists of small, single-center case series spanning several decades. We performed a multicenter study to assess the outcomes and factors associated with mortality after fetal diagnosis in the current era. Methods and Results-Fetuses diagnosed with Ebstein anomaly and tricuspid valve dysplasia from 2005 to 2011 wereincluded from 23 centers. The primary outcome was perinatal mortality, defined as fetal demise or death before neonatal discharge. Of 243 fetuses diagnosed at a mean gestational age of 27±6 weeks, there were 11 lost to follow-up (5%), 15 terminations (6%), and 41 demises (17%). In the live-born cohort of 176 live-born patients, 56 (32%) died before discharge, yielding an overall perinatal mortality of 45%. Independent predictors of mortality at the time of diagnosis were gestational age <32 weeks (odds ratio, 8.6; 95% confidence interval, 3.5-21.0; P<0.001), tricuspid valve annulus diameter z-score (odds ratio, 1.3; 95% confidence interval, 1.1-1.5; P<0.001), pulmonary regurgitation (odds ratio, 2.9; 95% confidence interval, 1.4-6.2; P<0.001), and a pericardial effusion (odds ratio, 2.5; 95% confidence interval, 1.1-6.0;© 2015 American Heart Association, Inc.Circulation characterized by apical displacement of the valve or leaflet deformation, respectively. 3 In severe cases of dysplasia, the tricuspid valve orifice may become unguarded. 4,5 Although there is a broad morphologic spectrum, these malformations lead to the same hemodynamic burden, namely, tricuspid regurgitation (TR) and its pathophysiological sequelae. Although older children and adults with EA/TVD may be asymptomatic for years, the diagnosis of EA/TVD in the perinatal period carries a poor prognosis. In the fetus, severe TR may lead to cardiomegaly, hydrops, and arrhythmia, with demise rates as high as 48%.6 Among prenatally diagnosed patients who survive to live birth, hemodynamic instability, cyanosis, and respiratory compromise are common. Although neonatal mortality approached 80 to 85% in early series, 7,8 various single-center series have reported reduced mortality in the past 2 decades, ranging from 17% to 56%. 9-12 Clinical Perspective on p 489Fetal risk factors for perinatal mortality have been identified, including lack of antegrade flow across the pulmonary valve and retrograde duct flow 9-12 and fetal distress. 12However, studies were limited by small sample sizes, with Yu et al 12 reporting the largest series to date with 46 prenatally diagnosed patients. The prognostic value of indices of cardiomegaly, such as the cardiothoracic area (CTA) ratio and the right atrial area index, has been mixed. [9][10][11][12][13] Importantly, hemodynamic factors with potentially important influences on perinatal mortality, such as right ventricular pressure and the presence of pulmonary regurgitation (PR), have not been investigated.Since our understanding of fetuses diagnose...

Background-Anti-SSA/Ro-associated third-degree congenital heart block is irreversible, prompting a search for early markers and effective therapy. Methods and Results-One hundred twenty-seven pregnant women with anti-SSA/Ro antibodies were enrolled; 95 completed an evaluable course in 98 pregnancies. The protocol included fetal echocardiograms performed weekly from 16 to 26 weeks' gestation and biweekly from 26 to 34 weeks. PR intervals Ͼ150 ms were considered prolonged, consistent with first-degree block. Ninety-two fetuses had normal PR intervals. Neonatal lupus developed in 10 cases; 4 were neonatal lupus rash only. Three fetuses had third-degree block; none had a preceding abnormal PR interval, although in 2 fetuses Ͼ1 week elapsed between echocardiographic evaluations. Tricuspid regurgitation preceded third-degree block in 1 fetus, and an atrial echodensity preceded block in a second. Two fetuses had PR intervals Ͼ150 ms. Both were detected at or before 22 weeks, and each reversed within 1 week with 4 mg dexamethasone. The ECG of 1 additional newborn revealed a prolonged PR interval persistent at 3 years despite normal intervals throughout gestation. No first-degree block developed after a normal ECG at birth. Heart block occurred in 3 of 16 pregnancies (19%) in mothers with a previous child with congenital heart block and in 3 of 74 pregnancies (4%) in mothers without a previous child with congenital heart block or rash (Pϭ0.067). Conclusions-Prolongation of the PR interval was uncommon and did not precede more advanced block. There was a trend toward more congenital heart block in fetuses of women with previously affected offspring than those without previously affected offspring. Advanced block and cardiomyopathy can occur within 1 week of a normal echocardiogram without initial first-degree block. Echodensities and moderate/severe tricuspid regurgitation merit attention as early signs of injury. (Circulation. 2008;117:485-493.)

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