Related Experiment Videos
Monocyte activation in alcoholic liver disease
Craig J McClain1, Daniell B Hill, Zhenyuan Song
1Department of Medicine, University of Louisville Medical Center and the Veterans Administration, Louisville, KY 40292, USA. craig.mcclain@louisville.edu
Alcohol (Fayetteville, N.Y.)
|June 14, 2002
Summary
Activated monocytes and macrophages contribute to alcoholic liver disease (ALD) pathogenesis by overproducing inflammatory cytokines like tumor necrosis factor (TNF) and interleukin (IL)-8, impacting zinc metabolism and liver injury.
Area of Science:
- Immunology
- Hepatology
- Metabolic Disorders
Background:
- Monocyte and macrophage activation are implicated in alcoholic liver disease (ALD) pathogenesis.
- ALD is associated with altered zinc metabolism and hypozincemia.
- Proinflammatory cytokines, such as TNF and IL-8, are key mediators in ALD.
Purpose of the Study:
- To investigate the role of monocyte activation and cytokine production in ALD.
- To explore the link between monocyte-derived substances, zinc metabolism, and ALD.
- To elucidate mechanisms of enhanced proinflammatory cytokine signaling in ALD.
Main Methods:
- Measurement of neopterin, adhesion molecules, cytokines, and chemokines in monocytes.
- Assessment of zinc metabolism and response to oral zinc supplementation in ALD patients.
- In vitro and in vivo studies on cytokine production, including TNF and IL-8, in response to stimuli like lipopolysaccharide (LPS).
- Evaluation of alterations in LPS-binding protein, CD14, Toll-like receptor 4, and TNF receptor density.
- Analysis of anti-inflammatory cytokine (IL-10) production and adenosine response.
Main Results:
- Monocytes in ALD produce a low-molecular-weight substance causing hypozincemia in rabbits.
- Monocytes in ALD overproduce TNF and IL-8, with TNF production being sensitive to antioxidants.
- Enhanced proinflammatory cytokine signaling involves alterations in LPS-binding protein, CD14, and TLR4.
- Increased TNF receptor density on monocytes and inadequate negative regulation of TNF were observed.
- Decreased IL-10 production and blunted response to adenosine contribute to inflammation.
Conclusions:
- Multiple mechanisms contribute to enhanced proinflammatory cytokine production by monocytes in ALD.
- Activated monocytes and macrophages play a significant role in ALD's metabolic complications and liver injury.
- Targeting monocyte activation and cytokine pathways may offer therapeutic strategies for ALD.