Metformin Reverses Development of Pulmonary Hypertension via Aromatase Inhibition.
Females are more susceptible to pulmonary arterial hypertension than males, although the reasons remain unclear. The hypoglycemic drug, metformin, is reported to have multiple actions, including the inhibition of aromatase and stimulation of AMP-activated protein kinase. Inhibition of aromatase using anastrazole is protective in experimental pulmonary hypertension but whether metformin attenuates pulmonary hypertension through this mechanism remains unknown. We investigated whether metformin affected aromatase activity and if it could reduce the development of pulmonary hypertension in the sugen 5416/hypoxic rat model. We also investigated its influence on proliferation in human pulmonary arterial smooth muscle cells. Metformin reversed right ventricular systolic pressure, right ventricular hypertrophy, and decreased pulmonary vascular remodeling in the rat. Furthermore, metformin increased rat lung AMP-activated protein kinase signaling, decreased lung and circulating estrogen levels, levels of aromatase, the estrogen metabolizing enzyme; cytochrome P450 1B1 and its transcription factor; the aryl hydrocarbon receptor. In human pulmonary arterial smooth muscle cells, metformin decreased proliferation and decreased estrogen synthesis by decreasing aromatase activity through the PII promoter site of Cyp19a1 Thus, we report for the first time that metformin can reverse pulmonary hypertension through inhibition of aromatase and estrogen synthesis in a manner likely to be mediated by AMP-activated protein kinase.
From the Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Afshan
A
Dean
From the Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom. mandy.maclean@glasgow.ac.uk.
Margaret
M
Nilsen
From the Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Lynn
L
Loughlin
From the Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Ian P
IP
Salt
From the Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Margaret R
MR
MacLean
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D047072:Aromatase Inhibitors / Q000378:metabolism / Q000494:pharmacology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D004967:Estrogens / Q000096:biosynthesis; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008168:Lung / Q000473:pathology; D008687:Metformin / Q000378:metabolism / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D011651:Pulmonary Artery; D051381:Rats; D066253:Vascular Remodeling / Q000187:drug effects*
D047072:Aromatase Inhibitors; D004967:Estrogens; D007004:Hypoglycemic Agents; D008687:Metformin; D001141:Aromatase; D055372:AMP-Activated Protein Kinases
AMP-activated protein kinase; aromatase; estrogen; metformin; pulmonary hypertension