Caffeine Prevents Protection in Two Human Models of Ischemic Preconditioning
Niels P. Riksen, MD*, ,*,
Zhigang Zhou, MD*,
Wim J.G. Oyen, MD, PhD ,
Rogier Jaspers, MD ,
Bart P. Ramakers, MSc*,
Rene M.H.J. Brouwer, MD, PhD,
Otto C. Boerman, PhD,
Neil Steinmetz, MD, PhD||,
Paul Smits, MD, PhD*, and
Gerard A. Rongen, MD, PhD*,
* Pharmacology-Toxicology
Internal Medicine
Nuclear Medicine
Cardiothoracic Surgery, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
|| North American Scientific, Theseus Imaging Division, Boston, Massachusetts
View larger version (8K):
[in a new window]
|
Figure 1 Schematic representation of the experimental protocol of the 2 randomized double-blinded in vivo studies. "IP" (ischemic preconditioning) indicates the 10-min period of ischemia (without concomitant exercise); "Isch Ex" (ischemic exercise) indicates the 10-min period of ischemia with isometric handgripping.
|
|
View larger version (14K):
[in a new window]
|
Figure 2 Annexin A5 targeting in the thenar muscle at 1 (open bars) and 4 (solid bars) h after reperfusion in the different groups (expressed as percent difference between experimental and control hand). The p values indicate differences between groups as assessed by repeated measures analysis of covariance with time (t = 1 and t = 4 h after reperfusion) as within-subject factor, group (as indicated on the x-axis) as between-subject factor, and workload as covariate. IP = ischemic preconditioning; Isch Ex = ischemic exercise.
|
|
View larger version (123K):
[in a new window]
|
Figure 3 Representative scintigraphic images of the experimental and control hands at 1 and 4 h after reperfusion in preconditioned subjects pre-treated with caffeine (A) and saline (B). Annexin targeting was 2% and 3% after saline administration (saline-ischemic preconditioning-ischemic exercise) and 19% and 27% after caffeine administration (caffeine-ischemic preconditioning-ischemic exercise) at 1 and 4 h, respectively.
|
|
View larger version (13K):
[in a new window]
|
Figure 4 The course of contractile force (expressed as percentage of baseline force) in time in control trabeculae (n = 17) with (open squares) and without (open circles) preconditioning and in caffeine pre-treated trabeculae (n = 13) with (filled squares) and without (filled circles) preconditioning. *p = 0.008 for the effect of preconditioning on post-ischemic recovery of contractile force in the saline group. For the sake of clarity, the symbols representing the non-preconditioned groups are slight shifted to the right. IP = ischemic preconditioning.
|
|
|
