Hamet
Programmed cell death in vascular disease and hypertension
16th Scientific Meeting of the International Society of Hypertension
ISH Abstract Book
(Jun) 16: 1996
This was an excellent lecture made by a first class investigator.
Apoptosis, an insidious, physiological type of cell death similar to
leaves, is followed by phagocytosis of neighboring cells. Apoptosis
probably starts with cell volume shrinkage and cytoskeleton
rigidification by g-glutamyl transferase, leading to DNA breakdown via
either Ca2+-dependent or Ca2+-independent H+-activated endonucleases.
The pro- and antiapoptotic gene pathway involves interleukin-1
b-converting enzyme and p53, balancing the survival signals provided
by growth factors such as bcl-2 and v-abl.
Many abnormalities of cell growth have been revealed in
hypertension, several of them in the neonatal stage, including heart
and kidney hyperplasia (Walter SV. Hypertension, 8: 520, 1986).
In vivo, these growth abnormalities are at best exemplified by
rarefaction of capillaries and remodeling of vessels. Since an
understanding of these processes requires the study of apoptosis in
hypertension, Hamet investigated the problem in various animal models
and demonstrated an increase of apoptosis in the heart, kidney and
brain of genetically-hypertensive rats and mice. Affected cells were
myocardiocytes in the heart and in the kidney glomerular mesangial
cells. Apoptosis and growth could be dissociated, as demonstrated by
g-irradiation which inhibits growth while stimulating apoptosis.
Furthermore, apoptotic process could precede hypertrophy. Such a
window of apoptosis has been observed after aortic occlusion with an
immediate short-lived peak preceding cardiac hypertrophy,
specifically in cardiomyocytes.
Comment: This review convincingly shows that the study
of apoptosis may substantially contribute to a better understanding of
remodeling, rarefaction and hyperplasia which occur in cardiovascular
pathology. In addition, investigation of apoptotic pathways will help
in the development of new therapeutic targets in hypertension and
cardiovascular diseases (Carmine Zoccali, M.D, Reggio Calabria,
Italy).
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16th Scientific Meeting of the International Society of Hypertension
H: Pathophysiology :
Vascular pathology
H: Pathophysiology :
Heart in hypertension