Fluorescence imaging microscopy of cellular markers in ischemic vs non-ischemic cardiomyopathy after left ventricular unloading.
BACKGROUND
The heart undergoes repair and initiates protective mechanisms via ventricular unloading. We examined the presence of 2 markers in pre-unloaded and post-unloaded human cardiac tissue that are important indicators of cardiac failure, tumor necrosis factor-alpha and inducible nitric oxide synthase. We also measured 2 nuclear transcription factors, NFkappaB50 and NFkappaB65, comparing quantities and localizations to determine if mechanical unloading reduced their presence, as these markers are also thought to be indicators of impending heart failure. Amounts and localizations in patients that had been diagnosed with either ischemic or non-ischemic cardiomyopathy were compared after mechanical unloading with a left ventricular assist device. To establish that unloading had been achieved, levels of atrial natriuretic protein were determined.


METHODS
Core biopsies were harvested at assist device implantation and removal. Fluorescence deconvolution microscopy image reconstructions of fluorescence probes were correlated with data obtained by western Blot and electrobility shift assays.


RESULTS
Statistically significant differences in localization and amounts of tumor necrosis factor and nitric oxide synthase were seen between pre- and post-assist device samples. Amounts of tumor necrosis factor and nitric oxide synthase in ischemic tissue were increased at the time of assist device removal, but decreased in dilated or idiomyopathic samples. Ventricular unloading resulted in reduced levels of natriuretic protein, with the greatest reduction being seen in ischemic tissue. Both NFkappaB50 and NFkappaB65 increased in ischemic tissue, but only NFkappaB50 in non-ischemic samples.


CONCLUSIONS
Changes in localization of the factors and altered levels of cytokine and nitric oxide synthase indicate that the heart switches to a "protective and repair" mode, and mechanical unloading allows this transition to occur. Observed changes were dependent on the etiology of the disease.
Bick
Roger J
RJ
Department of Organ Transplantation Cardiovascular Pathology, Texas Heart Institute and St. Lukes Episcopal Hospital, Houston, Texas, USA. roger.j.bick@uth.tmc.edu
Bagwell
Shannon H
SH
Jones
Chad E
CE
Poindexter
Brian J
BJ
Buja
L Maximilian
LM
Youker
Keith A
KA
Grigore
Alina
A
Clubb
Fred
F
Radovancevic
Branislav
B
Frazier
O Howard
OH
D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000648:ultrastructure*; D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D015153:Blotting, Western; D002311:Cardiomyopathy, Dilated / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D020878:Device Removal; D004586:Electrophoresis; D006352:Heart Ventricles / Q000378:metabolism / Q000648:ultrastructure; D006353:Heart-Assist Devices; D006801:Humans; D008856:Microscopy, Fluorescence; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure*; D019001:Nitric Oxide Synthase / Q000378:metabolism / Q000648:ultrastructure*; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000648:ultrastructure*
D015415:Biomarkers; D014409:Tumor Necrosis Factor-alpha; D009320:Atrial Natriuretic Factor; D019001:Nitric Oxide Synthase