An association between microvascular endothelial dysfunction, transcardiac nitric oxide production and pro-inflammatory cytokines after heart transplantation in humans.
Endothelial dysfunction anticipates the development of transplant coronary artery disease (TxCAD) observed more than 1 year after transplantation (HTx). We investigated whether in patients early after HTx myocardial inducible and constitutive nitric oxide synthases (iNOS; cNOS) are expressed and cardiac nitric oxide production occurs. Moreover, a possible relationship to alterations in endothelium dependent and independent vasomotor function was assessed. Forty-two transplant recipients were studied 37 +/- 5 days after HTx. Microvascular coronary flow velocity reserve (CFVR) was tested endothelium dependent (acetylcholine; 30 microg/min x 5 min/i.c.) and independent (adenosine; 160 microg/min x 5 min/i.c.) by Doppler flow wire. Flow velocity increase by a factor greater than 2 was considered normal. Quantitative coronary angiography was used to assess epicardial vasomotor function in response to the same stimuli. Myocardial iNOS and cNOS gene expression were detected by semiquantitative reversed transcriptase polymerase chain reaction. Plasma nitrite levels (microM) were measured by spectrophotometry. Cytokines (TNF-alpha, IL-6; pg/ml) were measured by enzyme linked immunosorbent assay. In 26.1% of patients (n = 11; group A) an impaired endothelium dependent CFVR (1.65 +/- 0.23 increase) was observed; in 73.9% (n = 31, group B) a normal endothelium dependent CFVR (3.0 +/- 0.7 increase; P = 0.003) was observed. Myocardial iNOS and cNOS gene expression did not differ between the two groups. Transcardiac cytokine production was noted in 58.8% of patients for IL-6 and in 53.3% for TNF-alpha. Coronary sinus (CS) levels of TNF-alpha, IL-6 and nitrite were higher in group A. A significant increase in nitrite production was found only in patients with impaired endothelium dependent CFVR (aorta: 43.9 +/- 3.7 vs CS: 52.8 +/- 5.6, P = 0.05), suggesting transcardiac nitric oxide production. In addition, CS nitrite levels correlated with CS TNF-alpha levels in patients with impaired CFVR (r = 0.44, P = 0.003). Microvascular endothelium dependent CFVR is impaired in 26% of patients early after HTx. Activation of cytokines and the NO pathway seem to be involved in this vasomotor dysfunction The association between cardiac nitric oxide production and TNF-alpha in this group indicates a chronic high immunologic process, which may represent an early and important target for therapy and prevention of TxCAD.
Wildhirt
S M
SM
Department of Cardiac Surgery, Grosshadern Hospital, Ludwig-Maximilians University, Munich, Germany. wildhirt@hch.med.uni-muenchen.de
Weis
M
M
Schulze
C
C
Conrad
N
N
Rieder
G
G
Enders
G
G
Hoepp
C
C
von Scheidt
W
W
Reichart
B
B
D000241:Adenosine; D000328:Adult; D015703:Antigens, CD / Q000097:blood; D001783:Blood Flow Velocity; D003326:Coronary Circulation; D016207:Cytokines / Q000097:blood*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D016027:Heart Transplantation / Q000276:immunology / Q000502:physiology*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008833:Microcirculation / Q000503:physiopathology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000097:blood; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D018608:Ultrasonography, Doppler
D015703:Antigens, CD; D016207:Cytokines; D015850:Interleukin-6; D009573:Nitrites; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D000241:Adenosine