Good performance of the criteria of American College of Medical Genetics and Genomics/Association for Molecular Pathology in prediction of pathogenicity of genetic variants causing thoracic aortic aneurysms and dissections

Molecular characterization and clinical investigation of patients with heritable thoracic aortic aneurysm and dissection

OBJECTIVES

Thoracic aortic aneurysm and dissection has a genetic predisposition and a variety of clinical manifestations. This study aimed to investigate the clinical and molecular characterizations of patients with thoracic aortic aneurysm and dissection and further explore the relationship between the genotype and phenotype, as well as their postoperative outcomes.

METHODS

A total of 1095 individuals with thoracic aortic aneurysm and dissection admitted to our hospital between 2013 and 2022 were included. Next-generation sequencing and multiplex ligation-dependent probe amplification were performed, and mosaicism analysis was additionally implemented to identify the genetic causes.

RESULTS

A total of 376 causative variants were identified in 83.5% of patients with syndromic thoracic aortic aneurysm and dissection and 18.7% of patients with nonsyndromic thoracic aortic aneurysm and dissection, including 8 copy number variations and 2 mosaic variants. Patients in the "pathogenic" and "variant of uncertain significance" groups had younger ages of aortic events and higher aortic reintervention risks compared with genetically negative cases. In addition, patients with FBN1 haploinsufficiency variants had shorter reintervention-free survival than those with FBN1 dominant negative variants.

CONCLUSIONS

Our data expanded the genetic spectrum of heritable thoracic aortic aneurysm and dissection and indicated that copy number variations and mosaic variants contributed to a small proportion of the disease-causing alterations. Moreover, positive genetic results might have a possible predictive value for aortic event severity and postoperative risk stratification.

The epithelial transcriptome and mucosal microbiota are altered for goats fed with a low-protein diet

Introduction

Feeding low protein (LP) diet to animals impose severe challenge to animals' immune homeostasis. However, limited knowledge about the underlying adaption mechanism of host and ruminal microbiota responding to LP diet were well understood. Herein, this study was performed to examine the changes in relative abundance of ruminal microbiota and host ruminal mucosal transcriptome profiles in response to a LP diet.

Methods

A total of twenty-four female Xiangdong balck goats with similar weight (20.64 ± 2.40 kg) and age (8 ± 0.3 months) were randomly assigned into two groups, LP (5.52% crude protein containing diet) and CON (10.77% crude protein containing diet) groups. Upon completion of the trial, all goats were slaughtered after a 16-hour fasting period in LiuYang city (N 28°15', E 113°63') in China. HE staining, free amino acids measurement, transcriptome analysis and microbiome analysis were applied to detect the morphology alterations, free amino acids profile alterations and the shift in host ruminal mucosal transcriptome and ruminal microbiota communities.

Results

Firstly, the results showed that feeding LP diet to goats decreased the rumen papilla width (P = 0.043), surface area (P = 0.013) and total ruminal free amino acids concentration (P = 0.016). Secondly, microbiome analysis indicated that 9 microbial genera, including Eubacterium and Prevotella, were enriched in LP group while 11 microbial genera, including Butyrivibrio and Ruminococcus, were enriched in CON group. Finally, in terms of immune-related genes, the expression levels of genes involved in tight junction categories (e.g., MYH11, PPP2R2C, and MYL9) and acquired immunity (e.g., PCP4 and CXCL13) were observed to be upregulated in the LP group when compared to the CON group.

Conclusion

Under the LP diet, the rumen exhibited increased relative abundance of pathogenic microbiota and VFA-degrading microbiota, leading to disruptions in immune homeostasis within the host's ruminal mucosa. These findings indicate that the ruminal microbiota interacts with host results in the disruption in animals' immune homeostasis under LP diet challenge.

Tracking an Elusive Killer: State of the Art of Molecular-Genetic Knowledge and Laboratory Role in Diagnosis and Risk Stratification of Thoracic Aortic Aneurysm and Dissection

The main challenge in diagnosing and managing thoracic aortic aneurysm and dissection (TAA/D) is represented by the early detection of a disease that is both deadly and “elusive”, as it generally grows asymptomatically prior to rupture, leading to death in the majority of cases. Gender differences exist in aortic dissection in terms of incidence and treatment options. Efforts have been made to identify biomarkers that may help in early diagnosis and in detecting those patients at a higher risk of developing life-threatening complications. As soon as the hereditability of the TAA/D was demonstrated, several genetic factors were found to be associated with both the syndromic and non-syndromic forms of the disease, and they currently play a role in patient diagnosis/prognosis and management-guidance purposes. Likewise, circulating biomarker could represent a valuable resource in assisting the diagnosis, and several studies have attempted to identify specific molecules that may help with risk stratification outside the emergency department. Even if promising, those data lack specificity/sensitivity, and, in most cases, they need more testing before entering the “clinical arena”. This review summarizes the state of the art of the laboratory in TAA/D diagnostics, with particular reference to the current and future role of molecular-genetic testing.