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Lack of C4d deposition may reveal susceptibility for ascending aortic dissection
Eetu Niinimaki1, Timo Paavonen, Timo Valo
1Heart Center, Tampere University Hospital, Tampere, Finland.
Insights
Lack of C4d deposits in the aortic wall may signal active remodeling and dissection. Complement activation, indicated by C4d, is linked to stable, non-dissecting aortas, suggesting diagnostic potential for aortic instability.
Area of Science:
- Immunology
- Vascular Biology
- Pathology
Background:
- Complement activation, indicated by C4d deposition, signifies immunological tissue reactivity.
- Understanding vascular reactivity in the aortic wall is crucial for diagnosing aortic conditions.
Purpose of the Study:
- To investigate the vascular reactivity of the aortic wall by characterizing C4d deposits.
- To determine the association between C4d deposition and aortic wall stability or dissection.
Main Methods:
- Histology and immunohistochemistry for C4d and various cellular markers were performed on 91 ascending aorta surgical samples.
- Samples were grouped based on the presence or absence of C4d deposits.
- Receiver operating characteristic (ROC) curve analysis was used to assess diagnostic accuracy.
Main Results:
- C4d deposits were found in 53 of 91 patients, primarily in the adventitia.
- Patients without C4d deposits showed increased intimal thickness, cellularity, and plasma cell inflammation.
- ROC analysis indicated C4d is associated with stable, non-dissecting ascending aorta (AUC 0.792) but not aortitis.
Conclusions:
- Absence of C4d may indicate aortic wall remodeling, potentially leading to aortic dissection.
- Immunologic complement factors, like C4d, could be valuable in diagnosing aortic instability post-surgery.
Objectives:
Complement activation as evidenced by C4d deposition indicates immunological tissue reactivity. We sought to study the vascular reactivity of the aortic wall by characterizing C4d deposits.
Design:
Aortic wall histology and immunohistochemistry for C4d, leukocytes, T- and B-lymphocytes, plasma cells, macrophages, endothelial cells, smooth muscle cells, cell proliferation, elastase, and Van-Gieson-staining were performed to 91 consecutive patients that underwent surgery for ascending aorta, and the samples were grouped according to presence of C4d deposits.
Results:
Fifty-three out of 91 patients had C4d deposits mainly within the adventitia (C4d +), whereas 38 patients lacked C4d deposits (C4d-) including decreased staining of intra-aortic vessels (p < 0.005). Intimal thickness and cellularity, together with inflammation consisting of plasma cells were increased in C4d- as compared with C4d + (p < 0.05). Receiver operating characteristic curve (ROC) analysis showed that C4d was associated with stabile nondissecting ascending aorta (AUC 0.792; SE 0.053; p = 0.000; 95% CI 0.688-0.895), but not with presence of aortitis per se (AUC 0.523; SE 0.069; p = 0.752; 95 % CI 0.388-0.658).
Conclusions:
Lack of C4d may indicate active remodeling of the aortic wall leading to aortic dissection (AD). Immunologic complement factors may be amenable to diagnosis of instability after aortic surgery.
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