Reduced number of subcutaneous adipocytes and metabolic disorders in patients with pulmonary emphysema

Abstract

Rationale: Wasting of the subcutaneous adipose tissue (SAT) is one of the clinical characteristics of patients with pulmonary emphysema, although visceral fat accumulation has been also reported. The capacity of SAT to store the surplus lipid would determine the overflow of lipid, resulting metabolic disorders like visceral fat accumulation. The aim of this study is to explore subcutaneous and vesceral adipocytes in patients with pulmonary emphysema. Methods: We evaluated formalin-fixed, paraffin-embedded human subcutaneous and visceral adipose tissue samples obtained from smokers with pulmonary emphysema and from healthy smokers. The adipocyte size w determined on hematoxylin & eosin-stained paraffin sections by quantifying the actual area of discrete adipocytes. The subcutaneous and visceral fat area were assessed using cross-sectional CT scans at the umbilicus level. Results: The areas of SAT were significantly decreased in smokers with pulmonary emphysema as compared to healthy smokers, even though the average adipocyte sizes were similar, suggesting reduced number of subcutaneous adipocytes in smokers with pulmonary emphysema. The areas of visceral adipose tissue were similar between smokers with pulmonary emphysema and healthy smokers, even though the average viseceral adipocyte sizes in smokers with emphysema tended to be increased as compared to healthy smokers, suggesting reduced number and subsequent hypertrophy of viseceral adipocytes in smokers with emphysema. Conclusion: This study showed the reduced number of subcutaneous adipocytes and hypertrophy of visceral adipocytes due to impaired capacity of SAT to store the surplus lipid in patients with pulmonary emphysema.