Imaging Mass Spectrometry Reveals a Unique Distribution of Triglycerides in the Abdominal Aortic Aneurysmal Wall.
The pathophysiology underlying abdominal aortic aneurysms (AAAs) remains unknown. In this study, we applied imaging mass spectrometry (IMS) to analyze the pathophysiology of the aneurysmal wall. Comparisons were performed between the tissue samples from the neck and the sac of the AAA, at a single time point, in 30 patients who underwent elective surgery of their AAAs. The localization of each lipid molecule in the aortic wall was assessed by IMS. Histopathological examination and IMS revealed a characteristic distribution of triglycerides (TGs) specifically in the aneurismal adventitia of the sac. This characteristic TG distribution was derived from an ectopic appearance of adipocytes in the adventitia. Furthermore, ectopic adipocyte accumulation in the aortic wall leads to the loss of the collagen fiber network subsequent to the wall rupture. The underlying mechanism of adipocyte accumulation involves the presence of adipose-derived stem cells (ADSCs) in the aneurismal adventitia and the expression of peroxisome proliferator-activated receptor gamma 2, a master regulator of adipocyte differentiation by some ADSCs. This study reveals new, previously overlooked aspects of AAA pathology.
Division of Vascular Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Hiroki
H
Tanaka
Nobuhiro
N
Zaima
Takeshi
T
Sasaki
Naoto
N
Yamamoto
Kazunori
K
Inuzuka
Masaki
M
Sano
Takaaki
T
Saito
Takahiro
T
Hayasaka
Naoko
N
Goto-Inoue
Kohji
K
Sato
Hirona
H
Kugo
Tatsuya
T
Moriyama
Hiroyuki
H
Konno
Mitsutoshi
M
Setou
Naoki
N
Unno
D017667:Adipocytes / Q000737:chemistry / Q000473:pathology; D063194:Adventitia / Q000737:chemistry / Q000473:pathology; D000368:Aged; D001012:Aorta, Abdominal / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D017544:Aortic Aneurysm, Abdominal / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D003094:Collagen / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D047495:PPAR gamma / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013234:Stem Cells / Q000737:chemistry / Q000473:pathology; D014280:Triglycerides / Q000032:analysis*
D047495:PPAR gamma; D014280:Triglycerides; D003094:Collagen