Thoracoabdominal aortic aneurysm in connective tissue disorder patients

Connective tissue disorders (CTDs) are a group of genetically triggered diseases in which the primary defect involves collagen and elastin protein assembly with potential vascular degenerations such as thoracoabdominal aortic aneurysm (TAAA) and dissection. These most commonly include Marfan syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome, and familial thoracic aortic aneurysm and dissection. Open surgical repair represents the standard approach in this specific group of patients. Extensive aortic replacements are generally performed in order to reduce long-term complications caused by the progressive dilatation of the remnant aortic segments. In the last decades, endovascular interventions have emerged as a valid alternative in patients affected by degenerative TAAA. However, in patients with CTD, this approach presents higher rates of reinterventions and postoperative complications with a disputable long-term durability, and it is nowadays performed for very selective indications such as severe comorbidities and urgent/emergent settings. Despite a deeper knowledge of the pathophysiological mechanisms involved in CTD, improvements in medical therapy, and a multidisciplinary approach fully involved in the management of these usually frailer patients, this specific group still represents a challenge. Further dedicated studies addressing mid-term and long-term outcomes in this selected population are needed.

An Overview of Investigational and Experimental Drug Treatment Strategies for Marfan Syndrome

Marfan syndrome (MFS) is a heritable connective tissue disorder caused by pathogenic variants in the gene coding for the extracellular matrix protein fibrillin-1. While the disease affects multiple organ systems, the most life-threatening manifestations are aortic aneurysms leading to dissection and rupture. Other cardiovascular complications, including mitral valve prolapse, primary cardiomyopathy, and arrhythmia, also occur more frequently in patients with MFS. The standard medical care relies on cardiovascular imaging at regular intervals, along with pharmacological treatment with β-adrenergic receptor blockers aimed at reducing the aortic growth rate. When aortic dilatation reaches a threshold associated with increased risk of dissection, prophylactic surgical aortic replacement is performed. Although current clinical management has significantly improved the life expectancy of patients with MFS, no cure is available and fatal complications still occur, underscoring the need for new treatment options. In recent years, preclinical studies have identified a number of potentially promising therapeutic targets. Nevertheless, the translation of these results into clinical practice has remained challenging. In this review, we present an overview of the currently available knowledge regarding the underlying pathophysiological processes associated with MFS cardiovascular pathology. We then summarize the treatment options that have been developed based on this knowledge and are currently in different stages of preclinical or clinical development, provide a critical review of the limitations of current studies and highlight potential opportunities for future research.

Insights on the Pathogenesis of Aneurysm through the Study of Hereditary Aortopathies

Thoracic aortic aneurysms (TAA) are permanent and localized dilations of the aorta that predispose patients to a life-threatening risk of aortic dissection or rupture. The identification of pathogenic variants that cause hereditary forms of TAA has delineated fundamental molecular processes required to maintain aortic homeostasis. Vascular smooth muscle cells (VSMCs) elaborate and remodel the extracellular matrix (ECM) in response to mechanical and biochemical cues from their environment. Causal variants for hereditary forms of aneurysm compromise the function of gene products involved in the transmission or interpretation of these signals, initiating processes that eventually lead to degeneration and mechanical failure of the vessel. These include mutations that interfere with transduction of stimuli from the matrix to the actin-myosin cytoskeleton through integrins, and those that impair signaling pathways activated by transforming growth factor-β (TGF-β). In this review, we summarize the features of the healthy aortic wall, the major pathways involved in the modulation of VSMC phenotypes, and the basic molecular functions impaired by TAA-associated mutations. We also discuss how the heterogeneity and balance of adaptive and maladaptive responses to the initial genetic insult might contribute to disease.