HerzSupplement - Pentalong von Actavis
HerzSupplement - Pentalong von Actavis
HerzSupplement - Pentalong von Actavis
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L-012-Chemilumineszenz [min]<br />
1,2 × 10 5<br />
0,8 × 10 5<br />
0,4 × 10 5<br />
0 × 10 5<br />
WT = Wildtyp<br />
B6 WT<br />
schiedliche Wirkung <strong>von</strong> GTN und PETN<br />
ist jedoch hochinteressant und wird vermutlich<br />
demnächst durch Mayer und Mitarbeiter<br />
aufgeklärt, die eine Konformationsänderung<br />
im Enzym für das unterschiedliche<br />
Verhalten <strong>von</strong> GTN und PETN<br />
hinsichtlich der Inaktivierung und RONS<br />
Bildung verantwortlich machen. n<br />
Summary<br />
The hemodynamic and antiischemic effects<br />
of nitroglycerin (GTN) are blunted due to<br />
the rapid development of a nitrate tolerance.<br />
Recent studies could identify new tolerance<br />
mechanisms such as the inhibition of the<br />
nitratebioactivating enzyme, the mitochondrial<br />
aldehyde dehydrogenase (AL<br />
DH2) as well as the formation of mitochondrial<br />
reactive oxygen and nitrogen species<br />
(RONS) leading to inhibition of GTN<br />
bioactivation. Based on these findings there<br />
is a direct link between nitrateinduced oxidative<br />
stress and the concept of desensitization<br />
(inhibition) of the nitrate bioactivation<br />
at the level of ALDH2. Recent animal studies<br />
suggest that reduced lipoic acid prevents<br />
oxidative inactivation of ALDH2 and that<br />
pentaerithrityl tetranitrate (<strong>Pentalong</strong> ® ,<br />
PETN) is devoid of nitrate tolerance induction<br />
due to intrinsic antioxidant properties<br />
(e.g. induction of heme oxygenase1 and ferritin).<br />
The fact that PETN prevents ALDH2<br />
inhibition is even more important since besides<br />
GTN also PETN and its trinitrate metabolite<br />
PETriN is bioactivated by ALDH2.<br />
A just completed study from our laboratory<br />
showed that PETN, in comparison with<br />
Herz 35 · 2010 · Supplement II © Urban & Vogel<br />
*<br />
GTN – ALDH -/- GTN<br />
Abb. 11: Messung der mitochondrialen RONS�Bildung in isolierten Mitochondrien <strong>von</strong> Wildtyp� und<br />
ALDH�2�knockout�Mäusen nach GTN�Inkubation mittels L�012�Chemilumineszenz.<br />
GTN, also acts qualitatively different with<br />
the purified human ALDH2. Interestingly,<br />
GTN caused a severe concentrationdependent<br />
inactivation of the ALDH2 activity<br />
and an increase in RONS formation (directly<br />
formed by ALDH2), whereas PETN only<br />
showed a moderate effect on these parameters.<br />
Detailed studies revealed that the reactive<br />
species formed by ALDH2 in the presence<br />
of GTN is most probably identical to<br />
peroxynitrite, which is responsible for uncoupling<br />
of endothelial NO synthase and<br />
subsequent endothelial dysfunction.<br />
Keywords: organic nitrates – bioactivation;<br />
superoxide – peroxynitrite – mitochondrial<br />
aldehyde dehydrogenase – mitochondrial<br />
oxidative stress – vascular function<br />
Danksagung<br />
Wir danken der Johannes Gutenberg<br />
Universität für die finanzielle Unterstützung<br />
durch MAIFOR und Förderfonds<br />
Beihilfen (A.D.) und der <strong>Actavis</strong> Deutschland<br />
GmbH für ihre fortwährende Unterstützung<br />
(A.D.).<br />
Literatur<br />
1. Abrams J. The role of nitrates in coronary heart dis�<br />
ease. Arch Intern Med 1995;155(4):357–364<br />
2. Stewart DD. Remarkable tolerance to nitroglycerin.<br />
Philadelphia Polyclinic 1888;6:43<br />
3. Elkayam U. Tolerance to organic nitrates: evidence,<br />
mechanisms, clinical relevance, and strategies for<br />
prevention. Ann Intern Med 1991;114:667–677<br />
4. Abrams J. A reappraisal of nitrate therapy. J Am Med<br />
Assoc 1988;259:396–401<br />
*<br />
Aus Schuhmacher et al. [40].<br />
Organische Nitrate<br />
33