Enzyme Therapy Lowers Blood Pressure

Cardiovascular disease researchers working with a mouse model have demonstrated a novel therapy for reducing hypertension.

Current hypertension therapies such as ACE (angiotensin converting enzyme) inhibitors block the formation of angiotensin II, a protein that causes blood vessels to constrict and increases blood pressure. In the current study, investigators at Northwestern University (Chicago, IL, USA) worked with a human recombinant form of angiotensin (Ang)-converting enzyme 2 (ACE2), which breaks down Ang II to form the peptide Ang-(1-7).

They reported in the January 2010 online edition of the journal Hypertension that infusing the recombinant enzyme (rACE2) into mice caused a dose-dependent increase in serum ACE2 activity but had no effect on kidney or cardiac ACE2 activity. The presence of rACE2 in the blood of the mice prevented the rapid hypertensive effect of injected Ang II, and this was associated with both a decrease in Ang II and an increase in Ang-(1-7) in plasma. During Ang II infusion, rACE2 effectively degraded Ang II and, in the process, normalized blood pressure. The mechanism of rACE2 action resulted from an increase in systemic, not tissue, ACE2 activity and the lowering of plasma Ang II rather than the attendant increase in Ang-(1-7).

"This therapeutic approach can also be superior to existing therapies that block the activity of the renin-angiotensin system, but only partially, and therefore, provide a more complete and effective suppression of this system to treat not just hypertension but many other medical conditions where angiotensin II over activity is undesirable," said senior author Dr. Daniel Batlle, professor of medicine at the Northwestern University.

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