Perivascular Adipose Tissue Inflammation and Coronary Artery Disease: An Autopsy Study Protocol

Daniela Souza Farias-Itao; Carlos Augusto Pasqualucci; Aline Nishizawa; Luiz Fernando Ferraz Silva; Fernanda Marinho Campos; Karen Cristina Souza da Silva; Renata Elaine Paraizo Leite; Lea Tenenholz Grinberg; Renata Eloah Lucena Ferretti-Rebustini; Wilson Jacob Filho; Claudia Kimie Suemoto

doi:10.2196/resprot.6340

Perivascular Adipose Tissue Inflammation and Coronary Artery Disease: An Autopsy Study Protocol

JMIR Res Protoc. 2016 Nov 18;5(4):e211. doi: 10.2196/resprot.6340.

Authors

Daniela Souza Farias-Itao^{1

2}, Carlos Augusto Pasqualucci^{1

2}, Aline Nishizawa^{1

2}, Luiz Fernando Ferraz Silva³, Fernanda Marinho Campos¹, Karen Cristina Souza da Silva^{1

2}, Renata Elaine Paraizo Leite^{2

4}, Lea Tenenholz Grinberg^{2

5}, Renata Eloah Lucena Ferretti-Rebustini^{2

6}, Wilson Jacob Filho^{2

4}, Claudia Kimie Suemoto^{1

2

4}

Affiliations

¹ Laboratory of Cardiovascular Pathology, Department of Pathology - LIM22, University of Sao Paulo Medical School, Sao Paulo, Brazil.
² Physiopathology in Aging Lab/Brazilian Aging Brain Study Group - LIM22, University of Sao Paulo Medical School, Sao Paulo, Brazil.
³ Department of Pathology, University of Sao Paulo Medical School, Sao Paulo, Brazil.
⁴ Discipline of Geriatrics, University of Sao Paulo Medical School, Sao Paulo, Brazil.
⁵ Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, United States.
⁶ Medical-Surgical Nursing Department, University of Sao Paulo School of Nursing, Sao Paulo, Brazil.

Abstract

Background: Perivascular adipose tissue (PAT) inflammation may have a role in coronary artery disease (CAD) pathophysiology. However, most evidence has come from samples obtained during surgical procedures that may imply in some limitations. Moreover, the role of B lymphocytes and inflammation in PAT that is adjacent to unstable atheroma plaques has not been investigated in humans using morphometric measurements.

Objective: The objective of this study is to investigate the inflammation in PAT, subcutaneous, and perirenal adipose tissues (SAT and PrAT) among chronic CAD, acute CAD, and control groups in an autopsy study.

Methods: Heart, SAT, and PrAT samples are collected from autopsied subjects in a general autopsy service, with the written informed consent of the next-of-kin (NOK). Sociodemographic and clinical data are obtained from a semistructure interview with the NOK. Coronary arteries are dissected and PAT are removed. Sections with the greatest arterial obstruction or unstable plaques, and the local with absence of atherosclerosis in all coronary arteries are sampled. PAT are represented adjacent to these fragments. Adipose tissues are fixed in 4% buffered paraformaldehyde solution and analyzed immunohistochemically for macrophages (CD68), macrophage polarization (CD11c for proinflammatory and CD206 for anti-inflammatory), B lymphocytes (CD20), and T lymphocytes (CD3). Slides will be scanned, and inflammatory cells will be quantified in 20 random fields. Participants will be categorized in CAD groups, after morphometric measurement of arterial obstruction and plaque composition analysis in accordance with American Heart Association classification. Three study groups will be investigated: acute CAD (at least one unstable plaque); chronic CAD (≥50% arterial obstruction); and controls (<50% arterial obstruction). Inflammatory cells in PAT, SAT, and PrAT will be counted and compared between groups using multivariate linear regression, adjusted for age, body mass index, hypertension, diabetes, alcohol use, and smoking.

Results: We present the methods of our study that was developed from 2 pilots. Currently, data collection and tissue processing are ongoing. Data collection, histology and immunochemistry procedures, and quantification of all inflammatory cells are expected to be concluded within 1 year.

Conclusions: This study will contribute for the understanding of the mechanisms of CAD pathophysiology because it will help to clarify the role of inflammation both in chronic and acute CAD.

Keywords: B lymphocytes; T lymphocytes; adipose tissue; atherosclerosis; coronary artery disease; inflammation; macrophages.

©Daniela Souza Farias-Itao, Carlos Augusto Pasqualucci, Aline Nishizawa, Luiz Fernando Ferraz Silva, Fernanda Marinho Campos, Karen Cristina Da Souza Silva, Renata Elaine Paraizo Leite, Lea Tenenholz Grinberg, Renata Eloah Lucena Ferretti-Rebustini, Wilson Jacob Filho, Claudia Kimie Suemoto. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 18.11.2016.