Pulmonary vascular reactivity and hemodynamic changes in elastase-induced emphysema in hamsters.
Changes in pulmonary hemodynamics and vascular reactivity in emphysematous hamsters were studied in an isolated lung preparation perfused at constant flow with blood and 3% dextran. Hamsters were treated with intratracheal porcine pancreatic elastase at 70 days of age, and experimental studies were conducted at 1, 3, and 8 mo after treatment. Baseline pulmonary arterial pressure in elastase-treated lungs was increased compared with saline-treated control lungs 1 mo after treatment, but this increase did not progress at 3 and 8 mo. Increases in pulmonary arterial pressure in elastase-treated lungs were temporally correlated with the morphological development of emphysema and right ventricular hypertrophy; both of these were evident at 1 mo after treatment and showed little change thereafter. Pressor responses to hypoxia and angiotensin II were not different between elastase-treated and control lungs at 1 and 3 mo. At 8 mo, however, pressor responses in emphysematous lungs to 0% O2 (but not to angiotensin II) were significantly increased. This was the result of a lack of the normal age-related fall in the hypoxic pressor response. Our results suggest that the right ventricular hypertrophy found in these emphysematous animals results from a chronically increased pulmonary vascular resistance. Furthermore, increases in pulmonary vascular resistance in the early development of emphysema are likely a result of the loss of vascular beds and supporting connective tissue.
Tseng
C M
CM
Department of Environmental Health Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205.
Qian
S
S
Mitzner
W
W
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001835:Body Weight / Q000502:physiology; D006224:Cricetinae; D004646:Emphysema / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D006400:Hematocrit; D006439:Hemodynamics / Q000502:physiology*; D008168:Lung / Q000473:pathology; D008297:Male; D008647:Mesocricetus; D009929:Organ Size / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010196:Pancreatic Elastase; D011652:Pulmonary Circulation / Q000502:physiology*; D014655:Vascular Resistance / Q000502:physiology
D000804:Angiotensin II; D010196:Pancreatic Elastase