Heritable thoracic aortic aneurysms and dissections (TAAD), including Marfan syndrome (MFS), currently lack a cure, and causative mutations have been identified for only a fraction of affected families. Here we identify the metalloproteinase ADAMTS1 and inducible nitric oxide synthase (NOS2) as therapeutic targets in individuals with TAAD. We show that Adamts1 is a major mediator of vascular homeostasis, given that genetic haploinsufficiency of Adamts1 in mice causes TAAD similar to MFS. Aortic nitric oxide and Nos2 levels were higher in Adamts1-deficient mice and in a mouse model of MFS (hereafter referred to as MFS mice), and Nos2 inactivation protected both types of mice from aortic pathology. Pharmacological inhibition of Nos2 rapidly reversed aortic dilation and medial degeneration in young Adamts1-deficient mice and in young or old MFS mice. Patients with MFS showed elevated NOS2 and decreased ADAMTS1 protein levels in the aorta. These findings uncover a possible causative role for the ADAMTS1-NOS2 axis in human TAAD and warrant evaluation of NOS2 inhibitors for therapy.

Our results support the role of miR-21 as a regulator of the fibrotic process that occurs in response to pressure overload in AS patients and underscore the value of circulating miR-21 as a biomarker for myocardial fibrosis.

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Sirtuin 3 (SIRT3) is a deacetylase that modulates proteins that control metabolism and protects against oxidative stress. Modulation of SIRT3 activity has been proposed as a promising therapeutic target for ameliorating metabolic diseases and associated cardiac disturbances. In this study, we investigated the role of SIRT3 in inflammation and fibrosis in the heart using male mice with constitutive and systemic deletion of SIRT3 and human cardiac AC16 cells. SIRT3 knockout mice showed cardiac fibrosis and inflammation that was characterized by augmented transcriptional activity of AP-1. Consistent with this, SIRT3 overexpression in human and neonatal rat cardiomyocytes partially prevented the inflammatory and profibrotic response induced by TNF-α. Notably, these effects were associated with a decrease in the mRNA and protein levels of FOS and the DNA-binding activity of AP-1. Finally, we demonstrated that SIRT3 inhibits FOS transcription through specific histone H3 lysine K27 deacetylation at its promoter. These findings highlight an important function of SIRT3 in mediating the often intricate profibrotic and proinflammatory responses of cardiac cells through the modulation of the FOS/AP-1 pathway. Since fibrosis and inflammation are crucial in the progression of cardiac hypertrophy, heart failure, and diabetic cardiomyopathy, our results point to SIRT3 as a potential target for treating these diseases.

Mitral annular area and shape did not change during the cardiac cycle after ring annuloplasty, regardless of ring type. Thus mitral annular area reduction, independent of intrinsic ring flexibility, is the chief mechanism responsible for the salutary effects of mitral ring annuloplasty.

Heart transplantation from controlled donation after the circulatory determination of death (cDCDD) may help to increase the availability of hearts for transplantation. During 2020, four heart transplants were performed at three different Spanish hospitals based on the use of thoraco‐abdominal normothermic regional perfusion (TA‐NRP) followed by cold storage (CS). All donors were young adults <45 years. The functional warms ischemic time ranged from 8 to 16 minutes. In all cases, the heart recovered sinus rhythm within 1 minute of TA‐NRP. TA‐NRP was weaned off or decreased <1L within 25 minutes. No recipient required mechanical support after transplantation and all were immediately extubated and discharged home (median hospital stay: 21 days) with an excellent outcome. Four livers, eight kidneys, and two pancreata were also recovered and transplanted. All abdominal grafts recipients experienced an excellent outcome. The use of TA‐NRP makes heart transplantation feasible and allows assessing heart function before organ procurement without any negative impact on the preservation of abdominal organs. The use of TA‐NRP in cDCDD heart donors in conjunction with cold storage following retrieval can eliminate the need to use ex situ machine perfusion devices, making cDCDD heart transplantation economically possible in other countries.