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TNF alpha is required for hypoxia-mediated right ventricular hypertrophy.
R M Smith1, J McCarthy, M N Sack
1Hatter Institute for Cardiology Research, University of Cape Town, Medical School, South Africa.
Molecular and Cellular Biochemistry
|May 17, 2001
Summary
Tumor necrosis factor-alpha (TNFα) plays a key role in chronic hypoxia-induced right ventricular hypertrophy. Mice lacking TNFα showed reduced pulmonary hypertension and cardiac remodeling during simulated high altitude.
Area of Science:
- Pulmonary Medicine
- Cardiovascular Physiology
- Immunology
Background:
- Hypoxia activates tumor necrosis factor-alpha (TNFα) in the lungs, inducing pulmonary vasoconstriction.
- The specific role of TNFα in chronic hypoxia-induced cardiopulmonary remodeling remains unclear.
Purpose of the Study:
- To investigate the role of TNFα in the development of right ventricular hypertrophy and pulmonary hypertension during chronic hypoxia.
- To evaluate the impact of TNFα deficiency on hypoxia-mediated cardiopulmonary responses.
Main Methods:
- Exposure of TNFα-null and wild-type mice to three weeks of hypobaric hypoxia (10% O2).
- Measurement of erythrocytosis, right ventricular systolic pressure, right ventricular hypertrophy, and lung wet weight.
Main Results:
- Both mouse strains developed similar erythrocytosis.
- Wild-type mice exhibited significant increases in right ventricular systolic pressure and hypertrophy, while TNFα-null mice did not.
- Lung wet weights increased similarly in both groups, suggesting TNFα's specific role in vascular and cardiac remodeling.
Conclusions:
- TNFα is integral to chronic hypoxia-induced right ventricular hypertrophy.
- TNFα signaling is a critical regulator of pulmonary hypertension and cardiac remodeling in response to sustained hypoxia.