Beta-Blocker Use during Pregnancy Correlates with Less Aortic Root Dilatation in Patients with Marfan's Syndrome.

BACKGROUND: Pregnant patients with Marfan's syndrome (MFS) are at an increased risk for adverse aortic outcomes. While beta-blockers are used to slow aortic root dilatation in nonpregnant MFS patients, the benefit of such therapy in pregnant MFS patients remains controversial. The purpose of this study was to investigate the effect of beta-blockers on aortic root dilatation during pregnancy in MFS patients. METHODS: This was a longitudinal single-center retrospective cohort study of females with MFS who completed a pregnancy between 2004 and 2020. Clinical, fetal, and echocardiographic data were compared in patients on- versus off-beta-blockers during pregnancy. RESULTS: A total of 20 pregnancies completed by 19 patients were evaluated. Beta-blocker therapy was initiated or continued in 13 (65%) of the 20 pregnancies. Pregnancies on-beta-blocker therapy experienced less aortic growth compared with those off-beta-blockers (0.10 [interquartile range, IQR: 0.10-0.20] vs. 0.30 cm [IQR: 0.25-0.35]; p = 0.03). Using univariate linear regression, maximum systolic blood pressures (SBP), increase in SBP, and absence of beta-blocker use in pregnancy were found to be significantly associated with greater increase in aortic diameter during pregnancy. There were no differences in rates of fetal growth restriction between pregnancies on- versus off-beta-blockers. CONCLUSION: This is the first study that we are aware of to evaluate changes in aortic dimensions in MFS pregnancies stratified by beta-blocker use. Beta-blocker therapy was found to be associated with less aortic root growth during pregnancy in MFS patients.

Murine echocardiography and ultrasound imaging.

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics. Echocardiography provides a powerful, non-invasive tool to serially assess cardiac morphometry and function in a living animal. However, using this technique on mice poses unique challenges owing to the small size and rapid heart rate of these animals. Until recently, few ultrasound systems were capable of performing quality echocardiography on mice, and those generally lacked the image resolution and frame rate necessary to obtain truly quantitative measurements. Newly released systems such as the VisualSonics Vevo2100 provide new tools for researchers to carefully and non-invasively investigate cardiac function in mice. This system generates high resolution images and provides analysis capabilities similar to those used with human patients. Although color Doppler has been available for over 30 years in humans, this valuable technology has only recently been possible in rodent ultrasound. Color Doppler has broad applications for echocardiography, including the ability to quickly assess flow directionality in vessels and through valves, and to rapidly identify valve regurgitation. Strain analysis is a critical advance that is utilized to quantitatively measure regional myocardial function. This technique has the potential to detect changes in pathology, or resolution of pathology, earlier than conventional techniques. Coupled with the addition of three-dimensional image reconstruction, volumetric assessment of whole-organs is possible, including visualization and assessment of cardiac and vascular structures. Murine-compatible contrast imaging can also allow for volumetric measurements and tissue perfusion assessment.

Small molecule disruption of G beta gamma signaling inhibits the progression of heart failure.

RATIONALE: Excess signaling through cardiac Gbetagamma subunits is an important component of heart failure (HF) pathophysiology. They recruit elevated levels of cytosolic G protein-coupled receptor kinase (GRK)2 to agonist-stimulated beta-adrenergic receptors (beta-ARs) in HF, leading to chronic beta-AR desensitization and downregulation; these events are all hallmarks of HF. Previous data suggested that inhibiting Gbetagamma signaling and its interaction with GRK2 could be of therapeutic value in HF. OBJECTIVE: We sought to investigate small molecule Gbetagamma inhibition in HF. METHODS AND RESULTS: We recently described novel small molecule Gbetagamma inhibitors that selectively block Gbetagamma-binding interactions, including M119 and its highly related analog, gallein. These compounds blocked interaction of Gbetagamma and GRK2 in vitro and in HL60 cells. Here, we show they reduced beta-AR-mediated membrane recruitment of GRK2 in isolated adult mouse cardiomyocytes. Furthermore, M119 enhanced both adenylyl cyclase activity and cardiomyocyte contractility in response to beta-AR agonist. To evaluate their cardiac-specific effects in vivo, we initially used an acute pharmacological HF model (30 mg/kg per day isoproterenol, 7 days). Concurrent daily injections prevented HF and partially normalized cardiac morphology and GRK2 expression in this acute HF model. To investigate possible efficacy in halting progression of preexisting HF, calsequestrin cardiac transgenic mice (CSQ) with extant HF received daily injections for 28 days. The compound alone halted HF progression and partially normalized heart size, morphology, and cardiac expression of HF marker genes (GRK2, atrial natriuretic factor, and beta-myosin heavy chain). CONCLUSIONS: These data suggest a promising therapeutic role for small molecule inhibition of pathological Gbetagamma signaling in the treatment of HF.