Heritable diseases of the blood vessels

Genetic profile in patients with complicated acute aortic syndrome: the GEN-AOR study

INTRODUCTION AND OBJECTIVES

Genetic testing is becoming increasingly important for diagnosis and personalized treatments in aortopathies. Here, we aimed to genetically diagnose a group of acute aortic syndrome (AAS) patients consecutively admitted to an intensive care unit and to explore the clinical usefulness of AAS-associated variants during treatment decision-making and family traceability.

METHODS

We applied targeted next-generation sequencing, covering 42 aortic diseases genes in AAS patients with no signs consistent with syndromic conditions. Detected variants were segregated by Sanger sequencing in available family members. Demographic features, risk factors and clinical symptoms were statistically analyzed by Fisher or Fisher-Freeman-Halton Exact tests, to assess their relationship with genetic results.

RESULTS

Analysis of next-generation sequencing data in 73 AAS patients led to the detection of 34 heterozygous candidate variants in 14 different genes in 32 patients. Family screening was performed in 31 relatives belonging to 9 families. We found 13 relatives harboring the family variant, of which 10 showed a genotype compatible with the occurrence of AAS. Statistical tests revealed that the factors associated with a positive genetic diagnosis were the absence of hypertension, lower age, family history of AAS and absence of pain.

CONCLUSIONS

Our findings broaden the spectrum of the genetic background for AAS. In addition, both index patients and studied relatives benefited from the results obtained, establishing the most appropriate level of surveillance for each group. Finally, this strategy could be reinforced by the use of stastistically significant clinical features as a predictive tool for the hereditary character of AAS.

CLINICALTRIALS

gov (Identifier: NCT04751058).

Thoracic Aortic Aneurysm and Dissection: Review and Recommendations for Evaluation

ABSTRACT

Aortic dissection and rupture (collectively termed "sudden aortic death") are commonly encountered by forensic pathologists, with an estimated incidence at autopsy between 0.6% and 7.7%. Despite this, there is no standard of practice for the evaluation of sudden aortic death at autopsy.Recent studies have shown 20% of patients with thoracic aortic aneurysm or dissection (TAAD) have an identifiable genetic syndrome, and 19% will have an affected first-degree relative. The past 2 decades have seen identification of new culprit genes and syndromes, which can have subtle or nonexistent external phenotypes. A high index of suspicion is warranted to identify possible hereditary TAAD (H-TAAD), allowing family members to obtain screening to avoid catastrophic vascular events. Forensic pathologists need broad knowledge of the spectrum of H-TAAD and awareness of the relative significance of hypertension, pregnancy, substance use, and microscopic changes of aortic architecture.This article reviews the common subtypes of H-TAAD, including Marfan syndrome, vascular Ehlers-Danlos, Loeys-Dietz, and familial thoracic aortic aneurysm and dissection. Recommendations for the evaluation of sudden aortic death at autopsy are presented, including (1) performance of a complete autopsy, (2) documentation of aortic circumference and valve morphology, (3) notifying family of the need for screening, and (4) preservation of a sample for potential genetic testing.

Col-F, a fluorescent probe for ex vivo confocal imaging of collagen and elastin in animal tissues

A new low-molecular-weight fluorescent probe, Col-F, that exhibits affinity to collagen and elastin, was used successfully in imaging of extracellular matrix in freshly excised animal tissues. Col-F readily penetrates between live cells into tissues and binds to fibers of collagen and elastin by a noncovalent mechanism. Fibers of collagen and elastin have been stained in a variety of tissues, including tendon, skeletal muscle, connective tissue, and arteries. Cells migrating in a Col-F-stained collagenous biomaterial were also imaged. No phototoxic effects were detected when live keratocytes were imaged in the in vitro culture in the presence of Col-F. In conclusion, Col-F provides a simple and convenient tool for fluorescence three-dimensional imaging of intricate collagenous and elastic structures in live and fixed animal tissues, as well as in collagen-containing biomaterials.

Chronic treatment with a broad-spectrum metalloproteinase inhibitor, doxycycline, prevents the development of spontaneous aortic lesions in a mouse model of vascular Ehlers-Danlos syndrome

There is no proven therapy or prevention for vascular Ehlers-Danlos syndrome (vEDS), a genetic disorder associated with the mutation of procollagen type III and characterized by increased fragility of vascular and hollow organ walls. Heterozygous COL3A1-deficient (HT) mice recapitulate a mild presentation of one of the variants of vEDS: haploinsufficiency for collagen III. Adult HT mice are characterized by increased metalloproteinase (MMP) activity, reduced collagen content in the arterial walls, and spontaneous development of various severity lesions in aorta. We hypothesized that chronic treatment with a MMP inhibitor would increase collagen content and prevent the development of spontaneous aortic lesions. HT mice were treated since weaning with the broad-spectrum MMP inhibitor doxycycline added to food. At the age of 9 months MMP-9 expression was twice as high in the tunica media of aorta in untreated HT mice, whereas total collagen content was 30% lower (p < 0.01) and the cumulative score of aortic lesions was eight times higher than in wild-type (WT) mice (p < 0.01). After 9 months of doxycycline treatment, MMP-9 activity, collagen content, and lesions in the aortas of HT mice were at the level of those of WT mice (p > 0.05). In the mouse model of collagen III haploinsufficiency treatment with broad-spectrum MMP inhibitor that was started early in life normalized increased MMP activity, reduced aortic collagen content in adults, and prevented the development of spontaneous aortic lesions. Our findings provide experimental justification for the clinical evaluation of the benefit of doxycycline at least in the haploinsufficient variety of vEDS.

The fittest person in the morgue?

The cardiovascular benefits of regular physical activity are well established (J. Sci. Med. Sport,7, 2004, 6). James Fixx wrote the best-selling book on running entitled The Complete Book of Running (1977), which led to an increase in popularity. However, when Fixx collapsed and died suddenly while running in 1984, people began to consider the adverse effects of sport on cardiac conditions. Going back in time, in 490 bc Phidippides, a young Greek messenger, ran 26.2 miles from Marathon to Athens delivering the news of the Greek victory over the Persians, and immediately collapsed and died. This is probably the first recorded incident of sudden death of an athlete running a marathon. According to Noakes (Med. Sci. Sports Exerc.,19, 1987, 187), one of the earliest reports on the association between running and cardiac risk was published in 1909, which claimed that school cross-country races over one mile for boys below the age of 19 years were totally inappropriate, and that the associated stress will cause damage in the heart and other organs. Death in athletes is highly publicized and has a substantial emotional impact on the community at large, given that athletes are perceived as the healthiest segment of society.

The haploinsufficient Col3a1 mouse as a model for vascular Ehlers-Danlos syndrome

Vascular Ehlers-Danlos syndrome is a rare genetic disorder resulting from mutations in the α-1 chain of type III collagen (COL3A1) and manifesting as tissue fragility with spontaneous rupture of the bowel, gravid uterus, or large or medium arteries. The heterozygous Col3a1 knockout mouse was investigated as a model for this disease. The collagen content in the abdominal aorta of heterozygotes was reduced, and functional testing revealed diminishing wall strength of the aorta in these mice. Colons were grossly and histologically normal, but reduced strength and increased compliance of the wall were found in heterozygotes via pressure testing. Although mice demonstrated no life-threatening clinical signs or gross lesions of vascular subtype Ehlers-Danlos syndrome type IV, thorough histological examination of the aorta of heterozygous mice revealed the presence of a spectrum of lesions similar to those observed in human patients. Lesions increased in number and severity with age (0/5 [0%] in 2-month-old males vs 9/9 [100%] in 14-month-old males, P < .05) and were more common in male than female mice (23/26 [88.5%] vs 14/30 [46.7%] in 9- to 21-month-old animals, P < .05). Haploinsufficiency for Col3a1 in mice recapitulates features of vascular Ehlers-Danlos syndrome in humans and can be used as an experimental model.

Screening for intracranial aneurysms in patients with bicuspid aortic valve

Objective: Bicuspid aortic valve (BAV) is a common congenital heart defect affecting half to 2% of the population. A generalized connective tissue disorder also involving the intracranial arteries has been suspected in this patient population. We therefore screened a group of patients with BAV for the presence of intracranial aneurysms.

Methods: Magnetic resonance angiography or CT angiography of the brain was used in 61 patients with BAV (age, 29–70 years [mean 48 years]) and in 291 controls (28–78 years [mean 56 years]).

Results: Intracranial aneurysms were detected in 6 of 61 patients with BAV (9.8%; 95% confidence interval [CI] 2.4%–17.3%). This was significantly higher than in the control population (3/291 [1.1%; 95% CI 0%–2.2%]) (p = 0.0012). Female sex (p = 0.02) and advanced age (p = 0.003), risk factors for intracranial aneurysm development, were more common in the control population than among the patients with a BAV. No significant differences were detected in age, sex, smoking, arterial hypertension, alcohol use, aortic diameter, or frequency of aortic coarctation between BAV patients with and without intracranial aneurysms.

Conclusion: In this case-control study, the frequency of intracranial aneurysms among our bicuspid aortic valve patient population was significantly higher than in the control population.

Histopathology of an iliac aneurysm in a case of Menkes disease

In Menkes disease, arterial tortuosity is frequent, whereas true aneurysms are rare. Here, we report aneurysmal pathology occurring in an infant with Menkes disease. An iliac aneurysm was diagnosed in a 2-month-old boy and attributed to Menkes syndrome on the basis of plasma copper deficiency. Samples of the aneurysmal wall were taken during surgery for histopathological analysis. As in other forms of aneurysm, the arterial wall was characterized by smooth muscle cell (SMC) disappearance, linked to SMC apoptosis and oxidative stress, areas of mucoid degeneration, and extracellular matrix breakdown, including disappearance of elastic fibers and presence of abnormal collagen.