Zusammenfassung
Fragestellung
Das stabile Prostazyklin–Analogon Iloprost hat während der Rechtsherzkatheteruntersuchung von Patienten, die für eine Transplantation evaluiert wurden, eine klinisch nachweisbare Zunahme des linksventrikulären Herzindex gezeigt. Ausgehend von diesen Ergebnissen formulierten wir die Arbeitshypothese, dass Iloprost einen direkt positiv inotropen Effekt ausübt.
Methodik
Stellvertretend für linksventrikuläres Myokard wurde von 22 Patienten rechtsatriales Myokard des Vorhofohres im Rahmen elektiv durchgeführter kardiochirurgischer Operationen (Bypass, Aortenklappenersatz, Kombination) entnommen. Aus den gewonnenen Präparaten wurden vier Trabekel präpariert und je zwei Trabekel der Kontroll– und Verumgruppe zugeordnet. Als Kontrollgruppe wurde diejenige Trabekelpopulation bezeichnet, die nur mit Iloprost–Trägerlösung (ohne Wirkstoff) stimuliert wurde. Die Verumgruppe enthielt alle Trabekel, die mit Iloprost in einer Konzentrationsreihe von 1 pg/ml bis 100 ng/ml stimuliert wurden. Die Versuche wurden im Organbad durchgeführt, so dass alle Präparate mit gepufferter Tyrodelösung gespült und elektrisch mit 1 Hertz (Hz) stimuliert worden sind. Die Ermittlung der Kontraktionskräfte erfolgte mit einem Kraftaufnehmer. Die maximal mögliche Kontraktionskraft wurde durch Stimulation mit 10–7 M Isoprenalin ermittelt.
Ergebnisse
Iloprost in den getesteten Konzentrationen übt weder einen positiv noch negativ inotropen Effekt auf rechtsatriales Myokardgewebe aus. Die ermittelten Kontraktionskräfte waren weder abhängig von der Masse der präparierten Trabekel, noch von einer medikamentösen Vorbehandlung mit Betablockern.
Schlussfolgerung
Die Arbeitshypothese konnte durch den gewählten Versuchsaufbau nicht bestätigt werden. Ob Iloprost direkt positiv inotrop auf linksventrikuläres Myokard wirkt, muss in einem anderen experimentellen Ansatz, z.B. in einem Tiermodell, überprüft werden.
Summary
Purpose
An increased pulmonary arterial pressure or transpulmonary gradient of the recipient is one of the most significant predictors of postoperative graft failure and increased mortality in patients undergoing orthotopic heart transplantation. For that reason heart transplant candidates should be evaluated preoperatively concerning their responsiveness of the pulmonary vasculature. During our right heart catheter examinations of transplant candidates the stable prostacyclin analogue iloprost was successfully introduced into the treatment of secondary pulmonary hypertension. Inhaled aerosolized iloprost effectively reduced mean pulmonary arterial pressure and was accompanied by an increase in cardiac index and stroke index. From these results we hypothesized that iloprost may cause a positive inotropic effect on myocardium.
Methods
Representative for left ventricular myocardium, right atrium appendages of 22 patients undergoing elective surgery (bypass grafting, aortic valve replacement and combination) were removed during installation of cardiopulmonary bypass. Immediately after excision, the specimens were transferred into Tyrode’s solution. Right atrial appendages were dissected to yield trabecular strips without endocardial damage and with fibers running parallel to the length. Preparations were mounted in an organ bath setting. Always two trabecular strips were referred to the control and iloprost group. Arterial strips were stimulated with iloprost (1 pg/ml to 100 ng/ml) and electrically stimulated at a frequency of 1 Hz. The developed tension of the preparation was recorded via a strain gauge on a special recorder. The maximum of contractility was ascertained by use of 10–7 isoprenaline.
Results
Iloprost did not influence the contractility of right atrial myocardium. The developed tension of the trabecula was not dependent on their mass or the preoperative treatment with betablockers.
Conclusion
With right atrial trabecular strips in the described experimental setting we were not able to confirm our hypothesis of a possible positive inotropic effect of iloprost.
References
Berti F, Rossoni G, Della Bella D, Villa LM, Buschi A, Trento F, Berti M, Tondo C (1993) Nitric oxide and prostacyclin influence coronary vasomotor tone in perfused rabbit heart and modulate endothelin–1 activity. J Cardiovasc Pharmacol 22:321–326
Bourge RC, Kirklin JK, Naftel DC, White C, Mason DA und Epstein AE (1991) Analysis and predictors of pulmonary vascular resistance after cardiac transplantation. J Thorac Cardiovasc Surg 101:432–444
Bruhn S, Kemming G, Kisch–Wedel H, Meisner F, Koehler C, Flondor M, Kübler W, Meßmer K, Zwissler B (2001) Wirkung von inhaliertem NO und PGI2 auf die linksventrikuläre Kontraktilität in vivo. Anästhsiologie & Intensivmedizin 42:450
Bugiardini R, Galvani M, Ferrini D, Gridelli C, Tollemeto D, Mari L, Puddu P, Lenzi S (1985) Myocardial ischemia induced by prostacyclin and iloprost. Clin Pharmacol Ther 38:101– 108
Cain BS, Meldrum DR, Joo KS, Wang JF, Meng X, Cleveland JC Jr, Banerjee A, Harken AH (1998) Human SERCA2a levels correlate inversely with age in senescent human myocardium. J Am Coll Cardiol 32:458–467
Fassina G, Tessari F, Dorigo P (1983) Positive inotropic effect of a stable analogue of PGI2 and of PGI2 on isolated guinea pig atria. Mechanism of action. Pharmacol Res Commun 15:735–749
Grant SM, Goa KL (1992) Iloprost. A review of its pharmacodynamic properties and therapeutical potential in peripheral vascular disease, myocardial ischemia and extracorporal circulation procedures. Drugs 43:889– 924
Haraldson E, Kieler–Jensen N, Nahthorst–Westfelt U, Bergh CH, Rickstein SE (1998) Comparison of inhaled nitric oxide and inhaled aerosolized prostacyclin in the evaluation of heart transplant candidates with elevated pulmonary vascular resistance. Chest 114:780–786
Kemming G, Kisch–Wedel H, Flondor M, Hofstetter C, Kreyling W, Thein E, Meisner F, Bruhn S, Zwissler B (2005) Improved ventricular function during inhalation of PGI2 aerosol partly relies on enhanced myocardial contractility. Eur Surg Res 37:9–17
Kisch–Wedel H, Kemming G, Meisner F, Flondor M, Kuebler WM, Bruhn S, Koehler C, Zwissler B (2003) The prostaglandins epoprostenol and iloprost increase left ventricular contractility in vivo. Intensive Care Med 29:1574–1583
Montalescot G, Drobinski G, Meurin P, Maclouf J, Sotirov I, Philippe F, Choussat R, Morin E, Thomas D (1998) Effects of prostacyclin on the pulmonary vascular tone and cardiac contractility of patients with pulmonary hypertension secondary to endstage heart failure. Am J Cardiol 82:749–755
Nakagawa O, Sasaki Y, Tanaka I, Usui T, Sando T, Muro S, Mori K, Itoh H, Yoshimasa T, Narumiya S (1995) Gene expression of prostacyclin receptor in the hypertrophied heart of spontaneously hypertensive rats. Clin Exp Pharmacol Physiol (Suppl 22):S270–272
Pavlovic M, Petkovic D, Cvetkovic M, Macut DJ, Zdjelar K, Nesic M, Bosnic O, Radulovic R, Mihajlovic M (1995) The influence of prostacyclin (PGI2) on contractile properties of isolated right ventricle of rat heart. Experientia 51:941–944
Pavlovic M, Petkovic D, Cvetkovic M, Zdjelar K, Starcevic V, Bosnic O (1992) Study of the mechanism of prostacyclin (PGI2) action on myocardial contractility. Agents Actions (Suppl 37):171–175
Rich S, McLaughlin VV (1999) The effects of chronic prostacyclin therapy on cardiac output and symptoms in primary pulmonary hypertension. J Am Coll Cardiol 34:1184–1187
Rybin V, Pak E, Alcott S und Steinberg S (2003) Developmental changes in beta2–adrenergic receptor signaling in ventricular myocytes: the role of Gi proteins and caveolae microdomains. Mol Pharmacol 63:1338–1348
Sablotzki A, Czeslick E, Gruenig E, Friedrich I, Schubert S, Borgermann J, Hentschel T (2003) First experiences with the stable prostacyclin analog iloprost in the evaluation of heart transplant candidates with increased pulmonary vascular resistance. J Thorac Cardiovasc Surg 125:960–962
Sablotzki A, Czeslick E, Schubert S, Friedrich I, Muhling J, Dehne MG, Grond S, Hentschel T (2002) Iloprost improves hemodynamics in patients with severe chronic cardiac failure and secondary pulmonary hypertension. Can J Anaesth 49:1076–1080
Sablotzki A, Hentschel T, Gruenig E, Schubert S, Friedrich I, Muhling J, Dehne MG, Czeslick E (2002) Hemodynamic effects of inhaled aerosolized iloprost and inhaled nitric oxide in heart transplant candidates with elevated pulmonary vascular resistance. Eur J Cardiothorac Surg 22:746–752
Stitham J, Stojanovic A, Hwa J (2002) Impaired receptor binding and activation associated with a human prostacyclin receptor polymorphism. J Biol Chem, p 15439–15444
Tenderich G, Koerner MM, Stuettgen B, Hornik L, Mirow N, Morshuis M, Mannebach H, Minami K, Koerfer R (1998) Does preexisting elevated pulmonary vascular resistance (transpulmonary gradient >15 mmHg or >5 wood) predict early and longterm results after orthotopic heart transplantation? Transplant Proc 30:1130–1131
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Czeslick, E., Rodenbäck, G., Wangemann, T. et al. Experimentelle Untersuchungen zum Einfluss des Prostazyklin–Analogons Iloprost auf die Kontraktilität humaner Vorhofmuskulatur. Z Herz- Thorax- Gefäßchir 19, 173–180 (2005). https://doi.org/10.1007/s00398-005-0502-4
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s00398-005-0502-4