Felodipine protects human atrial muscle from hypoxia-reoxygenation dysfunction: A force-frequency relationship study in an in vitro model of stunning

Katsunori Iwashiro, Anna Criniti, Riccardo Sinatra, Amos Adeyemo Dawodu, Giulia D'Amati, Francesco Monti, Luigi Pannarale, Paola Bernucci, Gian Luca Brancaccio, Antonella Vetuschi, Eugenio Gaudio, Pietro Gallo, Paolo Emilio Puddu

Research output: Contribution to journalArticle

Abstract

Aims: We aimed at investigating contractile changes after hypoxia- reoxygenation and dobutamine challenge in superfused human atrial pectinate muscle to see whether high versus low stimulation rate during hypoxia might account for outcome differences compatible with the definition of an in vitro model of myocardial stunning and whether pretreatment with the dihydropyridine Ca2+ entry blocker felodipine might afford protection. Methods: Human right atrial trabeculae obtained from adult patients were superfused in an organ bath with oxygenated (O2 content 16 ml/l) and modified (NaHCO3 25.7 mmol/l) Tyrode's solution at 37°(2. Dobutamine (1 nmol/l to 10 μmol/l) was superfused in 10 oxygenated preparations to select the optimal drug concentration to be used in another 22 which were randomized. Group (A) consisted of time-related controls (Tyrodes's solution for 225 min at cycle length (CL) 1600 ms and no dobutamine). There were two test groups, respectively. (B) low (1600 ms CL) and (C) high (400 ms CL) stimulation rate. After 60 min of stabilization, in groups B and C, hypoxic superfusion (O2 content 5 ml/l) lasted 60 min, then reoxygenation (60 min) and dobutamine challenge (1 μmol/l, 15 min) were performed. Analysis of variance for repeated measures with the Greenhouse-Geisser correction, and a repeated measures model with structured covariance (preparation mass, length, width and time-varying time to peak tension) matrices were used whereby grouping (G), time (T) and G T interaction were weighted. Force-frequency relationship and post-pausal potentiation were studied after each phase. Electrophysiology, histomorphometry and electron microscopy were carried out (n = 6). Felodipine (0.1 μmol/l, n = 5) pretreatment (15 min before hypoxia) was given in parallel experiments. Results: Time-related controls showed ≃10% per hour decrease of developed tension and the Paradise test provided ≃80% of control values. In test groups (as compared to baseline values) contractility was decreased ≃65% after hypoxia-reoxygenation and it increased ≃25% after dobutamine (G, 0.00652+-related diastolic processes thus helping index myocardial contractile reserve. Force-frequency relationship was negative at high stimulation rates, concomitant to an abrupt change of shape and duration of action potential with little time for Ca2+- related Ca2+ release and ensuing systolic processes. Felodipine pretreatment enabled an unblunted response to dobutamine. Histomorphometry showed an unexpected 'fibrotic core'. At electron microscopy, subendocardial and deep part of the same pectinate muscles showed identical degrees of degenerative lesions. Superfused samples showed, unexpectedly, less anoxic lesions than preparations fixed within 15 min from surgical explant, although lesions were higher than in samples fixed immediately after explant. Conclusions: This might be a relevant model, whereby pharmacological or physical interventions are tested. Native human atrial trabeculae might be used without dissection and/or preservatives. If high stimulation rate during hypoxia is used the power of hypothesis testing is maximized. Future studies with this material will be easier and comparatively smaller series might be investigated. Felodipine at low concentration was protective in this model.

Original languageEnglish
Pages (from-to)107-132
Number of pages26
JournalInternational Journal of Cardiology
Volume62
Issue number2
DOIs
Publication statusPublished - Nov 20 1997

Fingerprint

Felodipine
Dobutamine
Muscles
Electron Microscopy
Myocardial Stunning
Electrophysiology
Baths
Population Groups
Action Potentials
In Vitro Techniques
Hypoxia
Dissection
Analysis of Variance
Pharmacology
Pharmaceutical Preparations

Keywords

  • Analysis of variance
  • Calcium-entry blockers
  • Developed tension
  • Electron microscopy
  • Felodipine
  • Force-frequency relationship
  • Greenhouse-Geisser correction
  • Histomorphometry
  • Human atrial contractility
  • Human atrial electrophysiology
  • Human atrial trabeculae
  • Hypoxia
  • Myocardial protection
  • Post-pausal potentiation
  • Reoxygenation injury
  • Stunning

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Felodipine protects human atrial muscle from hypoxia-reoxygenation dysfunction : A force-frequency relationship study in an in vitro model of stunning. / Iwashiro, Katsunori; Criniti, Anna; Sinatra, Riccardo; Dawodu, Amos Adeyemo; D'Amati, Giulia; Monti, Francesco; Pannarale, Luigi; Bernucci, Paola; Brancaccio, Gian Luca; Vetuschi, Antonella; Gaudio, Eugenio; Gallo, Pietro; Puddu, Paolo Emilio.

In: International Journal of Cardiology, Vol. 62, No. 2, 20.11.1997, p. 107-132.

Research output: Contribution to journalArticle

Iwashiro, K, Criniti, A, Sinatra, R, Dawodu, AA, D'Amati, G, Monti, F, Pannarale, L, Bernucci, P, Brancaccio, GL, Vetuschi, A, Gaudio, E, Gallo, P & Puddu, PE 1997, 'Felodipine protects human atrial muscle from hypoxia-reoxygenation dysfunction: A force-frequency relationship study in an in vitro model of stunning', International Journal of Cardiology, vol. 62, no. 2, pp. 107-132. https://doi.org/10.1016/S0167-5273(97)00189-7
Iwashiro, Katsunori ; Criniti, Anna ; Sinatra, Riccardo ; Dawodu, Amos Adeyemo ; D'Amati, Giulia ; Monti, Francesco ; Pannarale, Luigi ; Bernucci, Paola ; Brancaccio, Gian Luca ; Vetuschi, Antonella ; Gaudio, Eugenio ; Gallo, Pietro ; Puddu, Paolo Emilio. / Felodipine protects human atrial muscle from hypoxia-reoxygenation dysfunction : A force-frequency relationship study in an in vitro model of stunning. In: International Journal of Cardiology. 1997 ; Vol. 62, No. 2. pp. 107-132.
@article{65177a8c89154f50848ddd3e457d05b0,
title = "Felodipine protects human atrial muscle from hypoxia-reoxygenation dysfunction: A force-frequency relationship study in an in vitro model of stunning",
abstract = "Aims: We aimed at investigating contractile changes after hypoxia- reoxygenation and dobutamine challenge in superfused human atrial pectinate muscle to see whether high versus low stimulation rate during hypoxia might account for outcome differences compatible with the definition of an in vitro model of myocardial stunning and whether pretreatment with the dihydropyridine Ca2+ entry blocker felodipine might afford protection. Methods: Human right atrial trabeculae obtained from adult patients were superfused in an organ bath with oxygenated (O2 content 16 ml/l) and modified (NaHCO3 25.7 mmol/l) Tyrode's solution at 37°(2. Dobutamine (1 nmol/l to 10 μmol/l) was superfused in 10 oxygenated preparations to select the optimal drug concentration to be used in another 22 which were randomized. Group (A) consisted of time-related controls (Tyrodes's solution for 225 min at cycle length (CL) 1600 ms and no dobutamine). There were two test groups, respectively. (B) low (1600 ms CL) and (C) high (400 ms CL) stimulation rate. After 60 min of stabilization, in groups B and C, hypoxic superfusion (O2 content 5 ml/l) lasted 60 min, then reoxygenation (60 min) and dobutamine challenge (1 μmol/l, 15 min) were performed. Analysis of variance for repeated measures with the Greenhouse-Geisser correction, and a repeated measures model with structured covariance (preparation mass, length, width and time-varying time to peak tension) matrices were used whereby grouping (G), time (T) and G T interaction were weighted. Force-frequency relationship and post-pausal potentiation were studied after each phase. Electrophysiology, histomorphometry and electron microscopy were carried out (n = 6). Felodipine (0.1 μmol/l, n = 5) pretreatment (15 min before hypoxia) was given in parallel experiments. Results: Time-related controls showed ≃10{\%} per hour decrease of developed tension and the Paradise test provided ≃80{\%} of control values. In test groups (as compared to baseline values) contractility was decreased ≃65{\%} after hypoxia-reoxygenation and it increased ≃25{\%} after dobutamine (G, 0.00652+-related diastolic processes thus helping index myocardial contractile reserve. Force-frequency relationship was negative at high stimulation rates, concomitant to an abrupt change of shape and duration of action potential with little time for Ca2+- related Ca2+ release and ensuing systolic processes. Felodipine pretreatment enabled an unblunted response to dobutamine. Histomorphometry showed an unexpected 'fibrotic core'. At electron microscopy, subendocardial and deep part of the same pectinate muscles showed identical degrees of degenerative lesions. Superfused samples showed, unexpectedly, less anoxic lesions than preparations fixed within 15 min from surgical explant, although lesions were higher than in samples fixed immediately after explant. Conclusions: This might be a relevant model, whereby pharmacological or physical interventions are tested. Native human atrial trabeculae might be used without dissection and/or preservatives. If high stimulation rate during hypoxia is used the power of hypothesis testing is maximized. Future studies with this material will be easier and comparatively smaller series might be investigated. Felodipine at low concentration was protective in this model.",
keywords = "Analysis of variance, Calcium-entry blockers, Developed tension, Electron microscopy, Felodipine, Force-frequency relationship, Greenhouse-Geisser correction, Histomorphometry, Human atrial contractility, Human atrial electrophysiology, Human atrial trabeculae, Hypoxia, Myocardial protection, Post-pausal potentiation, Reoxygenation injury, Stunning",
author = "Katsunori Iwashiro and Anna Criniti and Riccardo Sinatra and Dawodu, {Amos Adeyemo} and Giulia D'Amati and Francesco Monti and Luigi Pannarale and Paola Bernucci and Brancaccio, {Gian Luca} and Antonella Vetuschi and Eugenio Gaudio and Pietro Gallo and Puddu, {Paolo Emilio}",
year = "1997",
month = "11",
day = "20",
doi = "10.1016/S0167-5273(97)00189-7",
language = "English",
volume = "62",
pages = "107--132",
journal = "International Journal of Cardiology",
issn = "0167-5273",
publisher = "Elsevier Ireland Ltd",
number = "2",

}

TY - JOUR

T1 - Felodipine protects human atrial muscle from hypoxia-reoxygenation dysfunction

T2 - A force-frequency relationship study in an in vitro model of stunning

AU - Iwashiro, Katsunori

AU - Criniti, Anna

AU - Sinatra, Riccardo

AU - Dawodu, Amos Adeyemo

AU - D'Amati, Giulia

AU - Monti, Francesco

AU - Pannarale, Luigi

AU - Bernucci, Paola

AU - Brancaccio, Gian Luca

AU - Vetuschi, Antonella

AU - Gaudio, Eugenio

AU - Gallo, Pietro

AU - Puddu, Paolo Emilio

PY - 1997/11/20

Y1 - 1997/11/20

N2 - Aims: We aimed at investigating contractile changes after hypoxia- reoxygenation and dobutamine challenge in superfused human atrial pectinate muscle to see whether high versus low stimulation rate during hypoxia might account for outcome differences compatible with the definition of an in vitro model of myocardial stunning and whether pretreatment with the dihydropyridine Ca2+ entry blocker felodipine might afford protection. Methods: Human right atrial trabeculae obtained from adult patients were superfused in an organ bath with oxygenated (O2 content 16 ml/l) and modified (NaHCO3 25.7 mmol/l) Tyrode's solution at 37°(2. Dobutamine (1 nmol/l to 10 μmol/l) was superfused in 10 oxygenated preparations to select the optimal drug concentration to be used in another 22 which were randomized. Group (A) consisted of time-related controls (Tyrodes's solution for 225 min at cycle length (CL) 1600 ms and no dobutamine). There were two test groups, respectively. (B) low (1600 ms CL) and (C) high (400 ms CL) stimulation rate. After 60 min of stabilization, in groups B and C, hypoxic superfusion (O2 content 5 ml/l) lasted 60 min, then reoxygenation (60 min) and dobutamine challenge (1 μmol/l, 15 min) were performed. Analysis of variance for repeated measures with the Greenhouse-Geisser correction, and a repeated measures model with structured covariance (preparation mass, length, width and time-varying time to peak tension) matrices were used whereby grouping (G), time (T) and G T interaction were weighted. Force-frequency relationship and post-pausal potentiation were studied after each phase. Electrophysiology, histomorphometry and electron microscopy were carried out (n = 6). Felodipine (0.1 μmol/l, n = 5) pretreatment (15 min before hypoxia) was given in parallel experiments. Results: Time-related controls showed ≃10% per hour decrease of developed tension and the Paradise test provided ≃80% of control values. In test groups (as compared to baseline values) contractility was decreased ≃65% after hypoxia-reoxygenation and it increased ≃25% after dobutamine (G, 0.00652+-related diastolic processes thus helping index myocardial contractile reserve. Force-frequency relationship was negative at high stimulation rates, concomitant to an abrupt change of shape and duration of action potential with little time for Ca2+- related Ca2+ release and ensuing systolic processes. Felodipine pretreatment enabled an unblunted response to dobutamine. Histomorphometry showed an unexpected 'fibrotic core'. At electron microscopy, subendocardial and deep part of the same pectinate muscles showed identical degrees of degenerative lesions. Superfused samples showed, unexpectedly, less anoxic lesions than preparations fixed within 15 min from surgical explant, although lesions were higher than in samples fixed immediately after explant. Conclusions: This might be a relevant model, whereby pharmacological or physical interventions are tested. Native human atrial trabeculae might be used without dissection and/or preservatives. If high stimulation rate during hypoxia is used the power of hypothesis testing is maximized. Future studies with this material will be easier and comparatively smaller series might be investigated. Felodipine at low concentration was protective in this model.

AB - Aims: We aimed at investigating contractile changes after hypoxia- reoxygenation and dobutamine challenge in superfused human atrial pectinate muscle to see whether high versus low stimulation rate during hypoxia might account for outcome differences compatible with the definition of an in vitro model of myocardial stunning and whether pretreatment with the dihydropyridine Ca2+ entry blocker felodipine might afford protection. Methods: Human right atrial trabeculae obtained from adult patients were superfused in an organ bath with oxygenated (O2 content 16 ml/l) and modified (NaHCO3 25.7 mmol/l) Tyrode's solution at 37°(2. Dobutamine (1 nmol/l to 10 μmol/l) was superfused in 10 oxygenated preparations to select the optimal drug concentration to be used in another 22 which were randomized. Group (A) consisted of time-related controls (Tyrodes's solution for 225 min at cycle length (CL) 1600 ms and no dobutamine). There were two test groups, respectively. (B) low (1600 ms CL) and (C) high (400 ms CL) stimulation rate. After 60 min of stabilization, in groups B and C, hypoxic superfusion (O2 content 5 ml/l) lasted 60 min, then reoxygenation (60 min) and dobutamine challenge (1 μmol/l, 15 min) were performed. Analysis of variance for repeated measures with the Greenhouse-Geisser correction, and a repeated measures model with structured covariance (preparation mass, length, width and time-varying time to peak tension) matrices were used whereby grouping (G), time (T) and G T interaction were weighted. Force-frequency relationship and post-pausal potentiation were studied after each phase. Electrophysiology, histomorphometry and electron microscopy were carried out (n = 6). Felodipine (0.1 μmol/l, n = 5) pretreatment (15 min before hypoxia) was given in parallel experiments. Results: Time-related controls showed ≃10% per hour decrease of developed tension and the Paradise test provided ≃80% of control values. In test groups (as compared to baseline values) contractility was decreased ≃65% after hypoxia-reoxygenation and it increased ≃25% after dobutamine (G, 0.00652+-related diastolic processes thus helping index myocardial contractile reserve. Force-frequency relationship was negative at high stimulation rates, concomitant to an abrupt change of shape and duration of action potential with little time for Ca2+- related Ca2+ release and ensuing systolic processes. Felodipine pretreatment enabled an unblunted response to dobutamine. Histomorphometry showed an unexpected 'fibrotic core'. At electron microscopy, subendocardial and deep part of the same pectinate muscles showed identical degrees of degenerative lesions. Superfused samples showed, unexpectedly, less anoxic lesions than preparations fixed within 15 min from surgical explant, although lesions were higher than in samples fixed immediately after explant. Conclusions: This might be a relevant model, whereby pharmacological or physical interventions are tested. Native human atrial trabeculae might be used without dissection and/or preservatives. If high stimulation rate during hypoxia is used the power of hypothesis testing is maximized. Future studies with this material will be easier and comparatively smaller series might be investigated. Felodipine at low concentration was protective in this model.

KW - Analysis of variance

KW - Calcium-entry blockers

KW - Developed tension

KW - Electron microscopy

KW - Felodipine

KW - Force-frequency relationship

KW - Greenhouse-Geisser correction

KW - Histomorphometry

KW - Human atrial contractility

KW - Human atrial electrophysiology

KW - Human atrial trabeculae

KW - Hypoxia

KW - Myocardial protection

KW - Post-pausal potentiation

KW - Reoxygenation injury

KW - Stunning

UR - http://www.scopus.com/inward/record.url?scp=0031442059&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031442059&partnerID=8YFLogxK

U2 - 10.1016/S0167-5273(97)00189-7

DO - 10.1016/S0167-5273(97)00189-7

M3 - Article

C2 - 9431863

AN - SCOPUS:0031442059

VL - 62

SP - 107

EP - 132

JO - International Journal of Cardiology

JF - International Journal of Cardiology

SN - 0167-5273

IS - 2

ER -