Table 1.

Observed concentrations of the blood levels of inflammatory cytokines, adipokines and hormones in patients with chronic obstructive pulmonary disease (COPD).

Cytokines, Adipokines and Hormones	Primary Source	Functions	Changes in Blood Levels in COPD Patients	References
Adiponectin	Adipocytes	Insulin sensitizer, suppress inflammation	↑ compared to healthy smokers and nonsmkers; correlated with the residual volume, blood TNF-α levels and mortality; inversely correlated with the predicted %FEV1; ↑ during acute exacerbations	[30,31,32,33,34]
Leptin	Adipocytes, bronchial epithelial cells, alveolar type II pneumocytes, lung macrophages	Appetite control, promote inflammation; regulate hematopoiesis, angiogenesis, wound healing	↓ in COPD patients with low BMI compared to COPD patients with normal and high BMI and healthy control; ↑ and correlated with TNF-α during acute exacerbation; not correlated with TNF-α in stable COPD patients; plasma and sputum leptin levels are inversely correlated	[23,24,25,29]
Resistin	Peripheral blood mononuclear cells, adipocytes	Promote insulin resistance and inflammation through IL-6 and TNF-α production	Inversely correlated with FEV1% predicted	[35]
TNF-α	Stromal vascular fraction cells, adipocytes, monocytes	Promote inflammation; antagonize insulin signaling	↑ compared to healthy control; ↑ production from the peripheral blood monocytes in lean COPD patients	[13,14,15]
IL-6	Adipocytes, atromal vascular fraction cells, liver, muscle	Promote inflammation; appetite loss	↑ compared to healthy control	[14]
Ghrelin	X/A-like cells	Stimulate appetite and GH release	↑ in underweight patients compared with normal weight patients and healthy control subjects; positively correlated with residual lung volume; inversely correlated with FEV1% predicted	[36]

Abbreviations: ↑, increase; ↓, decrease.