Hepatocyte growth factor production may be related to the inflammatory response in patients with acute myocardial infarction

A phase I clinical study of naked DNA expressing two isoforms of hepatocyte growth factor to treat patients with critical limb ischemia

BACKGROUND

The purpose of the present phase I clinical trial was to evaluate the safety, tolerability, and preliminary efficacy of naked DNA therapy expressing two isoforms of hepatocyte growth factor (pCK-HGF-X7) in critical limb ischemia (CLI) patients.

MATERIALS AND METHODS

Twenty-one patients with CLI were consecutively assigned to receive increasing doses (cohort I: 4  mg; cohort II: 8  mg; cohort III: 12  mg; and cohort IV: 16  mg) of pCK-HGF-X7, which was administered into the ischemic calf and/or thigh muscle at days 1 and 15. A safety and tolerability evaluation and measurement of pain severity score using a visual analog scale (VAS), ulcer status, transcutaneous oxygen (TcPO(2) ) and ankle-brachial index (ABI) were performed throughout a 3-month follow-up period.

RESULTS

No serious adverse events were observed in any of the 21 patients for the 3-month follow-up period. A significant reduction in pain was observed in the treated patients, with the mean VAS decreasing from 5.95-1.64 (p  <  0.001). The mean ABI value increased from 0.49-0.63 (p  =  0.026) at 3-month follow-up. The mean TcPO(2) value on the dorsum of the foot, the anterior calf and posterior calf significantly increased from 28.25-39.28  mmHg (p  =  0.012), from 22.00-30.63  mmHg (p  =  0.046) and 32.05-47.19  mmHg (p  =  0.001) at 3-month follow-up, respectively. Wound healing improvement was observed in the six of nine patients that had an ulcer at baseline.

CONCLUSIONS

These results support the performance of a phase II randomized controlled trial with pCK-HGF-X7.

Monocyte activation state regulates monocyte-induced endothelial proliferation through Met signaling

Direct interaction of unactivated primary monocytes with endothelial cells induces a mitogenic effect in subconfluent, injured endothelial monolayers through activation of endothelial Met. We now report that monocytes' contact-dependent mitogenicity is controlled by activation-mediated regulation of hepatocyte growth factor. Direct interaction of unactivated monocytes with subconfluent endothelial cells for 12 hours resulted in 9- and 120-fold increase in monocyte tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1beta) mRNA levels and bitemporal spike in hepatocyte growth factor that closely correlates with endothelial Met and extracellular signal-related kinase (ERK) phosphorylation. Once activated, monocytes cannot induce a second wave of endothelial cell proliferation and endothelial Met phosphorylation and soluble hepatocyte growth factor levels fall off. Monocyte-induced proliferation is dose dependent and limited to the induction of a single cell cycle. Monocytes retain their ability to activate other endothelial cells for up to 8 hours after initial interaction, after which they are committed to the specific cell. There is therefore a profoundly sophisticated mode of vascular repair. Confluent endothelial cells ensure vascular quiescence, whereas subconfluence promotes vessel activation. Simultaneously, circulating monocytes stimulate endothelial cell proliferation, but lose this potential once activated. Such a system provides for the fine balance that can restore vascular and endothelial homeostasis with minimal overcompensation.

Vascular endothelial growth factors in cardiovascular medicine

The discovery of vascular endothelial growth factors (VEGFs) and their receptors has considerably improved the understanding of the development and function of endothelial cells. Each member of the VEGF family appears to have a specific function: VEGF-A induces angiogenesis (i.e. growth of new blood vessels from preexisting ones), placental growth factor mediates both angiogenesis and arteriogenesis (i.e. the formation of collateral arteries from preexisting arterioles), VEGF-C and VEGF-D act mainly as lymphangiogenic factors. The study of the biology of these endothelial growth factors has allowed a major progress in the comprehension of the genesis of the vascular system and its abnormalities observed in various pathologic conditions (atherosclerosis and coronary artery disease). The role of VEGF in the atherogenic process is still unclear, but actual evidence suggests both detrimental (development of a neoangiogenetic process within the atherosclerotic plaque) and beneficial (promotion of collateral vessel formation) effects. VEGF and other angiogenic growth factors (fibroblast growth factor), although initially promising in experimental studies and in initial phase I/II clinical trials in patients with ischemic heart disease or peripheral arterial occlusive disease, have subsequently failed to show significant therapeutic improvements in controlled clinical studies. Challenges still remain about the type or the combination of angiogenic factors to be administered, the form (protein vs. gene), the route, and the duration of administration.

Elevated plasma levels of oxidized low-density lipoprotein relate to the presence of angiographically detected complex and thrombotic coronary artery lesion morphology in patients with unstable angina

BACKGROUND

Increased levels of oxidized low-density lipoprotein (ox-LDL) are related to plaque instability, so the aim of the present study was to investigate whether there is a relationship between angiographic coronary plaque morphology in patients with unstable angina pectoris (UAP) and the level of ox-LDL.

METHODS AND RESULTS

Plasma ox-LDL levels were measured in 149 patients with UAP and in 88 control subjects, using a highly sensitive enzyme-linked immunosorbent assay method. Angiographic morphology of the culprit lesion was classified as either simple or complex based on the Ambrose classification. Plasma ox-LDL levels in patients with Braunwald class III were significantly higher than in patients with class I (p<0.0001) or in control subjects (p<0.0001). In each of the 3 Braunwald classes, plasma ox-LDL levels in patients with a complex lesion were significantly higher than in patients with a simple lesion. Multivariate logistic regression analysis revealed that ox-LDL level and Braunwald class III were independent factors associated with angiographically detected complex lesions.

CONCLUSION

In each Braunwald class of UAP, elevated plasma levels of ox-LDL closely relate to the presence of angiographically detected complex and thrombotic lesion morphology.

Hepatocyte growth factor and cardiovascular thrombosis in patients admitted to the intensive care unit

BACKGROUND

Hepatocyte growth factor (HGF) has been reported as a marker of atherosclerosis and of thrombi synthesis, but the relationship between HGF and proven coronary thrombi has not been described. The aim of this study was to investigate this relationship in patients with chest pain.

METHODS AND RESULTS

The study group comprised 107 patients with chest pain (61 acute myocardial infarction (AMI), 18 unstable angina, 15 stable angina, and 13 others; 65 males, 42 females; 66+/-11 years old). The presence of thrombi was evaluated by angiography, intravascular ultrasonography, angioscopy, and computed tomography. Serum HGF concentrations were measured using a new enzyme-linked immunosorbent assay. Serum HGF was significantly higher in the patients with AMI (335.0 +/-197.5 pg/ml), unstable angina (269.1+/-152.7 pg/ml), acute aortic dissection (320.3+/-116.5 pg/ml), and pulmonary thromboembolism (292.5+/-101.9 pg/ml), than in those with stable angina (171.2+/-56.1 pg/ml). Serum HGF concentration was also higher in those patients with proven thrombi than in those patients without (326.7+/-189.7 pg/ml vs 226.9+/-110.8 pg/ml).

CONCLUSION

Increased serum HGF concentrations correlate with the presence of thrombi in patients with acute coronary syndrome, acute aortic dissection, and pulmonary thromboembolism.

Office Cardiologists Cooperative Study on Whole Blood Rapid Panel Tests in Patients With Suspicious Acute Myocardial Infarction

BACKGROUND

The whole blood rapid troponin T test, used to determine the early diagnosis of acute myocardial infarction (AMI), is effective only for 3-4 h after onset.

METHODS AND RESULTS

The present office cardiologists cooperative study compared the diagnostic efficacy of a newly developed whole blood rapid panel test for heart-type fatty acid-binding protein (H-FABP) with that of the rapid troponin T test in 129 consecutive patients with suspicious AMI according to certain time-frames from onset to presentation. Thirty-one patients (24.0%) had a final diagnosis of AMI. The respective sensitivities of the rapid H-FABP and troponin T tests were 100% vs 50% (p<0.05) for patients presenting within 3 h of onset; 75% vs 0% for those between 3 and 6 h; 100% vs 60% for those between 6 and 12 h; and 100% vs 100% for those presenting later than 12 h. The respective specificities were 63% vs 96.3% (p<0.05); 93.8% vs 93.8%; 72.7% vs 100%; and 75.0% vs 87.5%. Negative predictive value was 100% vs 86.7%; 93.8% vs 78.9%; 100% vs 84.6%; and 100% vs 100%, respectively. Patients with non-AMI myocardial damage associated with unstable angina or severe heart failure showed positive H-FABP test results and blunted the specificity.

CONCLUSIONS

When using the novel rapid H-FABP test, cardiac emergency triage to exclude non-AMI patients should be effectively organized within 3 h of onset.

Increases in Interleukin-6 and Matrix Metalloproteinase-9 in the Infarct-Related Coronary Artery of Acute Myocardial Infarction

BACKGROUND

To elucidate the involvement of inflammation in coronary artery occlusion, the regional changes in cytokines and matrix metalloproteinases (MMPs) in the infarct-related coronary artery were determined in patients with acute myocardial infarction.

METHODS AND RESULTS

Cardiac catheterization was carried out within 24 h of the onset of infarction in 36 patients. Blood samples were collected from the infarct-related coronary artery, the ascending aorta and the peripheral vein. Plasma interleukin (IL)-6 concentrations were elevated in all 3 samples. Particularly, the plasma IL-6 concentrations were 14.4 pg/ml in the infarct-related coronary artery, a value significantly greater than the respective 8.0 pg/ml and 6.5 pg/ml in the ascending aorta and peripheral vein. Plasma IL-6 concentrations in the infarct-related coronary artery had positive correlation with all of the following references measured by intravascular ultrasound: external elastic membrane cross-sectional area (EEM-CSA) (r=0.47, p<0.01), lesion EEM-CSA (r=0.51, p<0.01) and plaque area (r=0.48, p<0.01). MMP-9 was increased regionally in the infarct-related coronary artery, at 11.8 ng/ml vs 8.2 ng/ml in the ascending aorta (p<0.001).

CONCLUSIONS

The present findings suggest that IL-6 at least is released from the ruptured vulnerable atherosclerotic plaque and that regional activation of macrophages is involved in the occlusive process of coronary artery in acute myocardial infarction.

Exercise-Induced Hepatocyte Growth Factor Production in Patients After Acute Myocardial Infarction-Its Relationship to Exercise Capacity and Brain Natriuretic Peptide Levels-

BACKGROUND

The hepatocyte growth factor (HGF) is a multifunctional cytokine with cardioprotective properties and potent myogenic activity for vascular endothelium. In patients after acute myocardial infarction, exercise training has the beneficial effects on cardiovascular adaptations. We hypothesized that exercise induces HGF production in those patients. If this hypothesis is correct, HGF production may be associated with clinical parameters of cardiovascular function.

METHODS AND RESULTS

In 20 patients after acute myocardial infarction, HGF levels in the pulmonary artery (HGF(PA)) and aorta (HGF(Ao)) were determined at rest and during supine submaximal exercise, with cardiac output (CO) measured by catheterization. Exercise-induced HGF production was calculated by using the following equation: [(HGF(PA)-HGF(Ao))xCO during exercise]-[(HGF(PA)-HGF(Ao))xCO at rest]. On a separate day, peak oxygen uptake (VO2) was determined during a symptom-limited upright cardiopulmonary exercise test. Exercise increased HGF production (from 1.6 +/- 3.0 to 9.0 +/- 6.3 microg/ml, p<0.001). Exercise-induced HGF production was inversely related to peak VO2 (r=-0.664, p<0.01) and positively related to levels of brain natriuretic peptide (BNP), a biochemical marker for post-infarction ventricular remodeling (r=0.686, p<0.01).

CONCLUSIONS

Exercise significantly increases HGF production. This phenomenon may play an important role in post-infarction patients, particularly with reduced exercise tolerance and elevated BNP levels.