Investigating tissue factor pathway inhibitor and other protease and protease inhibitors and their association with major adverse aortic events in patients with abdominal aortic aneurysm

Background

Abdominal aortic aneurysm (AAA) is characterized by the proteolytic breakdown of the extracellular matrix, leading to dilatation of the aorta and increased risk of rupture. Biomarkers that can predict major adverse aortic events (MAAEs) are needed to risk stratify patients for more rigorous medical treatment and potential earlier surgical intervention.

Objectives

The primary objective was to identify the association between baseline levels of these biomarkers and MAAEs over a period of 5 years.

Methods

Baseline levels of 3 proteases (matrix metalloproteinases 7, 8, and 10) and 3 protease inhibitors (tissue factor pathway inhibitor [TFPI], SerpinA12, SerpinB3) were investigated. Plasma levels of these biomarkers were quantified in 134 patients with AAA and 134 matched controls. Patients were followed for a 5-year period during which MAAEs were documented. The association between these markers and MAAEs was evaluated using Cox regression and Kaplan-Meier survival curves.

Results

TFPI was significantly elevated in patients with AAA and significantly associated with MAAE during the 5-year period (hazard ratio, 1.52; 95% CI, 1.15-2.01; P = .003) after adjusting for covariates. Kaplan-Meier survival analyses demonstrated that patients in the high TFPI group (defined as plasma levels >25.961 ng/mL) had significantly reduced freedom from the need for aortic repair and MAAEs.

Conclusion

These findings suggest that TFPI may serve as a valuable prognostic marker for the risk of MAAEs within 5 years in patients with AAA, potentially offering new tools for the medical management of patients with AAA.

Circulating miRNAs as biomarkers for diagnosis, surveillance and post-operative follow-up of abdominal aortic aneurysms

OBJECTIVE

To provide a summary of the current state of research in English medical literature on circulating miRNAs, as biomarkers for AAA. Additionally, for the most commonly mentioned circulating miRNAs in the literature, to attempt a documentation of the biological mechanisms underlying their role in AAA development.

METHODS

A literature search was undertaken in the MEDLINE database. Only reports that involved peripheral blood samples (whole blood, plasma, serum) were included. The following terms were used in combination: microrna, mirna, abdominal aortic aneurysm, human, circulating, plasma, serum, endovascular and EVAR.

RESULTS

A total of 25 reports, published from 2012 to 2022 were included with a total of 1259 patients with AAA, predominantly men (N= 1040, 90%). Six of these reports recruited healthy donors who underwent ultrasound screening for AAA as control samples. The majority of studies were undertaken in plasma samples and the most preferred microRNA profiling method was Real - Time quantitative polymerase chain reaction (qRT-PCR). The following nine miRNAs (out of a total of 76) were studied in more than two references: miR-145, miR-24, miR-33, miR-125, let-7, miR-15, miR-191, miR-29 and miR-133.

CONCLUSION

The nine miRNAs described in this study, are implicated in known pathogenetic mechanisms of AAA such as atherosclerosis, vascular smooth muscle cell phenotype switch and apoptosis, vascular inflammation, extracellular matrix degradation and lipid metabolism. Identifying disease-specific miRNAs, in combination with other clinical parameters, as indicators of AAA, is crucial for early diagnosis as well as follow-up of AAAs. For future research on miRNAs as AAA biomarkers, strict case and control group definitions, sample acquisition protocols, and miRNA expression profiling techniques are warranted.

Biomarkers in EndoVascular Aneurysm Repair (EVAR) and Abdominal Aortic Aneurysm: Pathophysiology and Clinical Implications

Circulating biomarkers have been recently investigated among patients undergoing endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Considering the plethora of small descriptive studies reporting potential associations between biomarkers and clinical outcomes, this review aims to summarize the current literature considering both the treated disease (post EVAR) and the untreated disease (AAA before EVAR). All studies describing outcomes of tissue biomarkers in patients undergoing EVAR and in patients with AAA were included, and references were checked for additional sources. In the EVAR scenario, circulating interleukin-6 (IL-6) is a marker of inflammatory reaction which might predict postoperative morbidity; cystatin C is a promising early marker of post-procedural acute kidney injury; plasma matrix metalloproteinase-9 (MMP-9) concentration after 3 months from EVAR might help in detecting post-procedural endoleak. This review also summarizes the current gaps in knowledge and future direction of this field of research. Among markers used in patients with AAA, galectin and granzyme appear to be promising and should be carefully investigated even in the EVAR setting. Larger prospective trials are required to establish and evaluate prognostic models with highest values with these markers.

Ascending Aneurysms in Heart Transplant Patients: A Rare Opportunity to Assess Heredity Versus Biological Environment

Three patients developed severe ascending aortic aneurysm requiring surgical resection after heart transplantation. In all 3 cases, the donor aorta of the transplant remained normal in caliber, despite the development of a large aneurysm in the native upper ascending aorta. The aneurysmal disease did not cross the suture line. (Level of Difficulty: Advanced.)

Systemic biomarkers currently implicated in the formation of abdominal wall hernia: A systematic review of the literature

BACKGROUND

Surgery to the abdominal wall is ubiquitous worldwide and hernia treatment is challenging and expensive, posing a critical need to tailor treatment to individual patient risk-factors. In this systematic review, we consider specific systemic factors with potential as biomarkers of hernia formation.

METHODS

A healthcare database-assisted search, following PRISMA guidelines, identified journal articles for inclusion and analysis.

RESULTS

14 biomarker studies were selected, comparing hernia patients and hernia-free controls, focusing on markers of extracellular matrix (ECM) remodelling and collagen turnover. Matrix metalloproteinase-2 was increased in patients with inguinal hernia. Markers of type IV collagen synthesis were increased in patients with abdominal wall hernia; while markers of fibrillar collagen synthesis were reduced. Additional other ECM signalling proteins differ significantly within published studies.

CONCLUSION

We identify a lack of high-quality evidence of systemic biomarkers in tailoring treatment strategies relative to patient-specific risks, but recognise the potential held within biomarker-based diagnostic studies to improve management of hernia pathogeneses.