Whole Exome Sequencing Uncovers the Genetic Complexity of Bicuspid Aortic Valve in Families with Early Onset Complications

Bicuspid Aortic Valve (BAV) is the most common adult congenital heart lesion with an estimated population prevalence of 1%. We hypothesize that early onset complications of BAV (EBAV) are driven by specific impactful genetic variants. We analyzed whole exome sequences (WES) to identify rare coding variants that contribute to BAV disease in 215 EBAV families. Predicted pathogenic variants of causal genes were present in 111 EBAV families (51% of total), including genes that cause BAV (8%) or heritable thoracic aortic disease (HTAD, 17%). After appropriate filtration, we also identified 93 variants in 26 novel genes that are associated with autosomal dominant congenital heart phenotypes, including recurrent deleterious variation of FBN2, MYH6, channelopathy genes, and type 1 and 5 collagen genes. These findings confirm our hypothesis that unique rare genetic variants contribute to early onset complications of BAV disease.

Transcriptomics Provides Novel Insights into the Regulatory Mechanism of IncRNA HIF1 A-AS1 on Vascular Smooth Muscle Cells

INTRODUCTION

Thoracic aortic aneurysm is a potentially fatal disease with a strong genetic contribution. The dysfunction of vascular smooth muscle cells (VSMCs) contributes to the formation of this aneurysm. Although previous studies suggested that long non-coding ribonucleic acid (RNA) hypoxia inducible factor 1 α-antisense RNA 1 (HIF1A-AS1) exerted a vital role in the progression and pathogenesis of thoracic aortic aneurysm, we managed to find a new regulatory mechanism of HIF1A-AS1 in VSMCs via transcriptomics.

METHODS

Cell viability was detected by the cell counting kit-8 assay. Cell apoptosis was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide double staining. Transwell migration assay and wound healing assay were performed to check the migration ability of HIF1A-AS1 on VSMCs. The NextSeq XTen system (Illumina) was used to collect RNA sequencing data. Lastly, reverse transcription-quantitative polymerase chain reaction confirmed the veracity and reliability of RNA-sequencing results.

RESULTS

We observed that overexpressing HIF1A-AS1 successfully promoted apoptosis, significantly altered cell cycle distribution, and greatly attenuated migration in VSMCs, further highlighting the robust promoting effects of HIF1A-AS1 to thoracic aortic aneurysm. Moreover, transcriptomics was implemented to uncover its underlying mechanism. A total of 175 differently expressed genes were identified, with some of them enriched in apoptosis, migration, and cell cycle-related pathways. Intriguingly, some differently expressed genes were noted in vascular development or coagulation function pathways.

CONCLUSION

We suggest that HIF1A-AS1 mediated the progression of thoracic aortic aneurysm by not only regulating the function of VSMCs, but also altering vascular development or coagulation function.

Chronic Blunt Traumatic Thoracic Aortic Injuries: Report of three cases from Oman

Blunt thoracic aortic injuries are potentially lethal. Those who survive may form an organised haematoma in the periadventitial space resulting in a pseudoaneurysm, which may be identified incidentally decades later. While the role of thoracic endovascular aortic repair (TEVAR) in acute settings has been established, its role in chronic cases is yet to be defined. We report three cases that were diagnosed incidentally six, nine and 18 years after the injury. Two were managed by TEVAR while the third declined intervention and is on annual follow-up. Patients with asymptomatic and stable pseudoaneurysms of the descending thoracic aorta should be offered surveillance versus TEVAR because the risk of rupture is not negligible, whilst taking into account the patient’s level of physical activity. These three cases highlight the importance of early diagnosis of aortic injuries in blunt trauma and its grading.

Mean Platelet Volume-to-Platelet Count Ratio, Mean Platelet Volume-to-Lymphocyte Ratio, and Red Blood Cell Distribution Width-Platelet Count Ratio as Markers of Inflammation in Patients with Ascending Thoracic Aortic Aneurysm

OBJECTIVE

Ascending thoracic aortic aneurysm (ATAA), seen in adults, is an important cause of morbidity and mortality. In this study, we aimed to evaluate the levels of mean platelet volume (MPV), mean platelet volume-to-platelet count ratio (MPVPCR), mean platelet volume-to-lymphocyte ratio (MPVLR), and red cell distribution width platelet count ratio (RDWPCR) in patients with thoracic aortic aneurysm.

METHODS

105 patients admitted to the emergency department were diagnosed with thoracic aortic aneurysm between January and December 2014, and 100 healthy individuals were involved in this retrospective study. MPV, MPVLR, MPVPCR and RDWPCRs were calculated at the time of admission.

RESULTS

Platelet and lymphocyte levels were found to be significantly lower in the patient group when compared to the healthy group (P<0.001, P<0.001, respectively), while MPV, MPVPCR, MPVLR and RDWPCR were found to be significantly higher (P<0.001, P<0.001, P<0.001, and P=0.013, respectively). In the patient group, the high-sensitivity C-reactive protein was significantly higher (P<0.001), and the neutrophil (P=0.062) was also higher. In ROC analysis, MPVPCR had the highest sensitivity (80%) and RDWPCR had the highest specificity (72%).

CONCLUSION

The results for MPV, MPVPCR, MPVLR and RDWPCR can be evaluated as useful parameters in the emergency clinical approach in the evaluation of inflammatory activity in ATAA patients. More extensive studies are required to address the role of these parameters in determining the severity of the disease.

Could Cerebrospinal Fluid Biomarkers Offer Better Predictive Value for Spinal Cord Ischaemia Than Current Neuromonitoring Techniques During Thoracoabdominal Aortic Aneurysm Repair - A Systematic Review

Objective

Cerebrospinal fluid (CSF) drainage is a technique that has significantly reduced the incidence of spinal cord ischaemia (SCI). We present results of a systematic review to assess the literature on this topic in relation to thoracoabdominal aortic aneurysm repair (TAAR).

Methods

Major medical databases were searched to identify papers related to CSF biomarkers measured during TAAAR.

Results

Fifteen papers reported measurements of CSF biomarkers with 265 patients in total. CSF biomarkers measured included S-100ß, neuron-specific endolase (NSE), lactate, glial fibrillary acidic protein A (GFPa), Tau, heat shock protein 70 and 27 (HSP70, HSP27), and proinflammatory cytokines. Lactate and S-100ß were reported the most, but did not correlate with SCI, which was also the case with NSE and TAU. GFPa showed significant CSF level rises, both intra and postoperative in patients who suffered SCI and warrants further investigation, similar results were seen with HSP70, HSP27 and IL-8.

Conclusions

Although there is significant interest in this topic, there still remains a significant lack of high-quality studies investigating CSF biomarkers during TAAR to detect SCI. A large and multicentre study is required to identify the significant role of each biomarker.

An L-Shaped Incision for an Extensive Thoracic Aortic Aneurysm and Coronary Artery Bypass Using the Left Internal Thoracic Artery

An L-shaped incision combining an upper half mid-sternotomy and a left antero-lateral thoracotomy at the fourth intercostal space has been proposed by several authors for extensive aneurysms involving the aortic arch and the proximal thoracic descending aorta. This approach usually requires the division of the left internal thoracic artery at its mid position, thus making it unusable for coronary artery bypass. We herein report a modified surgical approach for simultaneous extensive arch and proximal thoracic descending aorta replacement and coronary artery bypass using the left internal thoracic artery combining a left antero-lateral thoracotomy at the sixth intercostal space and upper mid-sternotomy. The visualization of the whole diseased aorta down to the level below the hilum of the left lung was good, and the integrity of the left internal thoracic artery graft was preserved by early heparin administration before sternotomy.

Pathophysiology of thoracic aortic aneurysm (TAA): is it not one uniform aorta? Role of embryologic origin

Thoracic aortic aneurysm (TAA) is a clinically silent and potentially fatal disease whose pathophysiology is poorly understood. Application of data derived from animal models and human tissue analysis of abdominal aortic aneurysms may prove misleading given current evidence of structural and biochemical aortic heterogeneity above and below the diaphragm. Genetic predisposition is more common in TAA and includes multi-faceted syndromes such as Marfan, Loeys-Dietz, and type IV Ehlers-Danlos as well as autosomal-dominant familial patterns of inheritance. Investigation into the consequences of these known mutations has provided insight into the cell signaling cascades leading to degenerative remodeling of the aortic medial extracellular matrix (ECM) with TGF-β playing a major role. Targeted research into modifying the upstream regulation or downstream effects of the TGF-β1 pathway may provide opportunities for intervention to attenuate TAA progression.