The use of angiotensin-converting enzyme inhibitors has revolutionized the
treatment of hypertension
and the treatment of patients with renal insufficiency, especially
diabetics. Converting enzyme
inhibitors, however, may not inhibit angiotensin II formation in all
tissues, as there are enzymes
other than ACE present in the heart and elsewhere which can convert
angiotensin I to angiotensin II,
and as there are pathways whereby angiotensin II can be made from
angiotensinogen bypassing
angiotensin II and again not dependent on ACE. A separate issue is the
fact that ACE inhibitor
treatment results in increased generation of bradykinin. Whether increased
bradykinin generation is
a helpful or
deleterious action of ACE inhibitors remains to be determined. The recent
availability of losartan,
as a prototype
drug of an angiotensin II (type 1) receptor blocker may be another
important step forward in
antihypertensive therapy. AII receptor blockers should block the effects
of angiotensin II as well
as, or even better than, ACE inhibitors, but be devoid of effects on
bradykinin. For example, use
of AII receptor blockers is not associated with cough, a common problem
with ACE inhibitors.
Losartan and several of the other available AII blockers are selective
antagonists for the type 1
AII receptor. By blocking the cell growth actions of the type I receptor,
they should have
beneficial effects in reducing AII-mediated damage to the heart,
vasculature, and kidneys. Also,
AII type 1 receptor blockers such as losartan may indirectly stimulate
angiotensin II type 2
receptors, which are present in the failing heart, and which may have
beneficial, antiproliferative
or antihypertrophic effects.
At the 11th meeting of the American Society for Hypertension, at a special
symposium sponsored by
an unrestricted education grant from Merck U.S. Human Health Division, a
panel of experts who are
conducting both basic and clinical research with the AII receptor blockers
presented the state of
knowledge in this very exciting new area. HDCN, in cooperation with the
American Society of
Hypertension, and with the generous consent of the speakers, is making
available the audiotapes of
most of the sessions from this symposium, along with their transcripts.
(J.T. Daugirdas, M.D.,
Editor, HDCN)
Incidentally, if you haven't already, you will need to
register with HDCN to access these talks.
The Faculty
Drs. Reid, Unger, Devereux (not shown), de Zeeuw, and Weber
John Reid, M.D., Professor of Medicine and
Therapeutics, University
of Glasgow, Scotland. Thomas Unger, M.D., Professor of
Phamarcology and Experimental
Hypertension, University of Kiel. Richard B. Devereux, M.D., Professor of
Medicine, Cornell
University Medical College. Dick de Zeeuw, M.D., Professor of Clinical
Pharmacology, University
of Groningen, The Netherlands. Michael A. Weber, M.D. (Chairman).,
Professor of Medicine at the
State University of New York Health Sciences Center, Brooklyn, NY.
Dr. Michael Weber.
Let me start by welcoming all
of you here this morning on behalf of the American Society of
Hypertension. These are our 11th annual meetings. Each year the
meetings have gotten larger, more ambitious, more diverse. I think
those of you who stay for the full program, which I hope is everyone
in this room, will find that it is going to be a very exciting and a
very fulfilling meeting. Today this is the first session of the
meetings. It is a symposium that is being put on by the Society,
supported by an unrestricted educational grant from Merck. I would
like to thank our colleagues at Merck for their support of this
program and for their support of other important activities of the
Society. Today we are going to talk, obviously, about angiotensin II,
as a target for intervention in cardiovascular disease. Naturally we
are going to have some focus on hypertension. But I think as the
program evolves, you will see that the heart, the kidney, the arteries
and all the other critical structures that are important for us are
going to be discussed in depth and detail. I'm delighted that we have
been able to assemble such a distinguished faculty, and I'm looking
forward to a very exciting morning.