Serum hepatocyte growth factor in patients with peripheral arterial occlusive disease.

Hepatocyte growth factor (HGF) is a multifunctional protein implicated in tissue regeneration, wound healing, and angiogenesis. We measured serum HGF concentrations in 37 patients with peripheral arterial occlusive disease (PAOD). Among them, 36 patients underwent arteriography. Serum HGF concentrations were also measured in 40 control subjects who remained free of vascular, liver, kidney, or lung disease. Patients with PAOD showed elevated serum HGF concentrations compared with control subjects (0.40+/-0.02 vs. 0.19+/-0.01 ng/mL; P<0.001). Serum HGF concentrations were significantly higher in smokers compared with nonsmokers (0.45+/-0.03 vs. 0.35+/-0.02 ng/mL; P = 0.003). The serum HGF concentrations in patients with collaterals tended to be higher than those in patients without collaterals (0.43+/-0.03 vs. 0.35+/-0.02 ng/mL; P = 0.06). Moreover, in patients who underwent bypass surgery or angioplasty, serum HGF concentrations decreased from 0.41+/-0.03 to 0.21+/-0.04 ng/mL after treatment (P<0.001). Serum HGF may be an useful marker for the diagnosis of PAOD. HGF may play an important role in angiogenesis and collateral vessel growth in PAOD.     

Translational research to identify clinical applications of hepatocyte growth factor

Hepatocyte growth factor (HGF), originally purified from the plasma of patients with fulminant hepatic failure, has been shown to carry out various physiological functions. HGF not only stimulates liver regeneration, but also acts as an antiapoptotic factor in in vivo experimental models. Therefore, HGF is a promising therapeutic agent for the treatment of fatal liver diseases, including fulminant hepatic failure. After performing a number of preclinical tests, our group began an investigator-initiated registered phase I/II clinical trial of patients with fulminant hepatic failure to examine the safety and clinical efficacy of recombinant human HGF. In this article, we will discuss the basic research results as well as the translational research that underpins current attempts to use HGF in various clinical settings.     

Antithrombotic therapy in peripheral arterial disease

The management of elderly patients with peripheral arterial disease requires a multidisciplinary and individualized approach, especially for patients requiring intervention and for those on antithrombotic therapy. Communication between the patient's primary physician, consulting medical specialists, and vascular surgeon is essential because all may contribute synergistically to deliver optimal care to the patient. This article reviews the pathophysiology of peripheral arterial disease, and data regarding the use of antiplatelet and anticoagulant agents.     

Cell therapy in peripheral arterial disease

Management of advanced obstructive vascular disease affecting the extremities poses tremendous challenges for physicians and patients. Peripheral arterial disease is often a consequence of obstructive atherosclerosis affecting the ileofemoral circulation but is also rarely a result of nonatherosclerotic conditions such as thromboangiitis obliterans (Buerger's disease). Consequences range from the presence of asymptomatic obstruction to intermittent claudication, development of rest pain, ulceration, gangrene, and amputation. A relatively new and promising approach using cell therapy has recently been developed to treat intractable symptoms related to ischemia in subjects with peripheral arterial disease in whom conventional medical therapy and revascularization modalities have been exhausted.     

Antithrombotic therapy in peripheral arterial disease

The management of elderly patients with peripheral arterial disease requires a multidisciplinary and individualized approach, especially for patients requiring intervention and for those on antithrombotic therapy. Communication between the patient's primary physician, consulting medical specialists, and vascular surgeon is essential because all may contribute synergistically to deliver optimal care to the patient. This article reviews the pathophysiology of peripheral arterial disease and data regarding the use of antiplatelet and anticoagulant agents.     

Magnetic resonance evaluation of peripheral arterial disease

This article provides the reader with a clinically relevant practical approach to obtaining high-quality magnetic resonance angiograms of the lower extremities. The physics underlying this imaging are discussed as they relate to practical matters such as contrast timing schemes. Model protocols for various scanners are presented, and the rationale for the choices. In addition to the standard core protocol, alternative protocols are presented, so that the reader will have a sense of the full palette of options available, and be readily able to appreciate the relative advantages and disadvantages of each. Applications of these protocols in imaging various disorders then are discussed, with clinical exams presented. Pearls and pitfalls regarding imaging techniques and various tricks of the trade also are discussed.     

Meta-analysis of randomized, controlled clinical trials in angiogenesis: gene and cell therapy in peripheral arterial disease

We aim to determine the efficacy and safety of gene and cell angiogenic therapies in the treatment of peripheral arterial disease (PAD) and evaluate them for the first time by a meta-analysis. We include in the formal meta-analysis only the randomized placebo-controlled phase 2 studies with any angiogenic gene or cell therapy modality to treat patients with PAD (intermittent claudication, ulcer or critical ischemia) identified by electronic search in MEDLINE and EMBASE databases (1980 to date). Altogether, 543 patients are analyzed from six randomized, controlled trials that are comparable with regard to patient selection, study design, and endpoints. We perform the meta-analysis regarding clinical improvement (improvement of peak walk time, relief in rest pain, ulcer healing or limb salvage) and rate of adverse events. At the end of treatment, therapeutic angiogenesis shows a significantly clinical improvement as compared to placebo in patients with PAD (odds ratio [OR] = 1.437; 95% confidence interval [CI] = 1.03?2.00; P = 0.033). The response rate (improvement of peak walk time) of the pooled groups according to clinical severity does not significantly differ for gene therapy as compared with placebo in the treatment of claudicating patients (OR = 1.304; 95% CI = 0.90?1.89; P = 0.16). Otherwise, we find significant efficacy of the treatment in critical ischemia (OR = 2.20; 95% CI = 1.01?4.79; P = 0.046). The adverse events rates show a slightly significantly higher risk of potential nonserious adverse events (edema, hypotension, proteinuria) in the treated group (OR = 1.81; 95% CI = 1.01?3.38; P = 0.045). We find no differences in mortality from any cause, malignancy, or retinopathy. The patients with PAD, and particularly those with critical ischemia, improve their symptoms when treated with angiogenic gene and cell therapy with acceptable tolerability.     

Masterclass series in peripheral arterial disease. Antiplatelet therapy for peripheral arterial disease and claudication

Peripheral arterial disease (PAD) of the lower extremities is a common and potentially life-threatening manifestation of systemic atherosclerosis. Significant PAD is identified by an ankle brachial index (ABI) < 0.90; its presence is strongly associated with the major modifiable cardiac risk factors. Early detection and treatment of asymptomatic PAD is a current focus of numerous cardiovascular guideline organizations as less than a third of patients report typical claudication symptoms. This has created an ever-increasing treatment gap, whereby millions of eligible patients are inadequately treated. Risk factor management including exercise, smoking cessation, and aggressive treatment of lipids and blood pressure are essential in PAD patients. However, life-long antiplatelet therapy provides additional reductions in vascular events beyond aggressive risk factor management. The use of aspirin as well as more potent antiplatelet therapies such as thienopyridines holds promise for reducing atherothrombosis in this very high-risk population.     

Circulating hepatocyte growth factor level but not basic fibroblast growth factor level is elevated in angiography-proven symptomatic peripheral artery disease

Circulating vasogenic factors may be up-regulated in response to ischemia to promote angiogenesis in patients with peripheral artery disease (PAD). Studies on this are limited in number and size, and results are inconsistent, especially regarding basic fibroblast growth factor (bFGF) level. From March 1999 to April 2004, all consecutive patients with lower limb PAD having serum samples at the time of intervention were recruited. The diameter of the primary PAD lesion had to be at least 70% stenotic at the lower limb artery. Control subjects, who underwent angiography, were free of PAD, coronary disease, and other major medical diseases. Serum samples were analyzed for circulating hepatocyte growth factor (HGF) and bFGF levels. Patients with PAD (n = 60) had higher circulating HGF levels (mean +/- SEM, 1,544 +/- 238 vs 970 +/- 129 pg/mL; P = .04) but similar bFGF distribution tertiles (P = .55) compared with control subjects (n = 30). Thirty-six patients with summed PAD lesion lengths exceeding 5 cm demonstrated a significantly higher circulating HGF level compared with control subjects (mean +/- SEM, 1,701 +/- 335 vs 970 +/- 129 pg/mL; P = .048). Patients with concurrent coronary artery disease tend to have a higher circulating HGF level (mean +/- SEM, 1,606 +/- 365 vs 970 +/- 129 pg/mL; P = .06) but not a higher bFGF level compared with control subjects. Circulating HGF level, but not bFGF level, is significantly elevated in patients with symptomatic angiographically documented PAD, especially in those with more extensive involvement.     

Increase in peripheral blood flow by intravenous administration of prostaglandin E1 in patients with peripheral arterial disease, accompanied by up-regulation of hepatocyte growth factor.

Since endothelial damage is a trigger for the progression of atherosclerosis, we evaluated the clinical utility of prostaglandin E1 (PGE1) in relation to peripheral blood flow and regulation of hepatocyte growth factor (HGF), an angiogenic growth factor, in patients with peripheral arterial disease (PAD). Fourteen male patients with PAD who showed the characteristic symptoms of arteriosclerosis obliterans (Fontaine I: n=2; Fontaine II: n=4; Fontaine III: n=2; Fontaine IV: n=6), confirmed by angiography, were enrolled in this study. Patients were administrated synthetic PGE1 at a dose of 120 microg per day for 14 consecutive days. Measurement of peripheral blood flow and serum HGF concentration was performed before PGE1 treatment and after 14 days of administration. Interestingly, intravenous administration of PGE1 for 2 weeks significantly increased the blood flow as assessed by a laser Doppler imager (p<0.01). In patients with Fontaine III and IV, serum HGF concentration was significantly higher than that in patients with Fontaine I or II and normal subjects. Of importance, administration of PGE1 further increased serum HGF concentration as compared to that before treatment (p<0.01). The increase in circulating HGF might work as a compensatory mechanism to decrease local HGF expression in patients with PAD, since HGF acts as an angiogenic growth factor with anti-apoptotic actions on endothelial cells. Moreover, to confirm the stimulatory effect of PGE1 on HGF in vessels, we employed an in vitro culture system. PGE1 increased HGF production and the growth of human cultured vascular endothelial cells. The stimulatory effect of PGE1 on HGF production might be due to an increase in cAMP, since forskolin and 8-bromo-cAMP induced HGF production. In conclusion, we demonstrated that administration of PGE1 stimulated peripheral blood flow, accompanied by an increase in systemic HGF concentration. Also, our in vitro data suggested that PGE1 augmented not only the systemic HGF level, but also local HGF production, probably through cAMP accumulation, resulting in improvement of endothelial function and blood flow.     

Serum concentrations of vascular endothelial growth factor and monocyte-colony stimulating factor in peripheral arterial disease.

Vascular endothelial growth factor (VEGF) strongly promotes angiogenesis, and monocyte-colony stimulating factor (M-CSF) regulates the differentiation, proliferation, and survival of monocytes. Both VEGF and M-CSF are expressed in atherosclerotic lesions. The present study was performed to clarify the role of VEGF and M-CSF in the development of peripheral artery disease (PAD). The serum VEGF and M-CSF concentrations were determined in patients with arteriosclerosis obliterans (ASO) and thromboangitis obliterans (TAO). In both patient groups the serum VEGF concentrations were significantly higher than those in the control subjects. In contrast, the serum M-CSF concentrations in the ASO patients were significantly higher than those in both the TAO patients and control subjects, but there were no differences in the M-CSF concentrations between the TAO patients and control subjects. There was no correlation between the serum concentrations of VEGF and M-CSF. In conclusion, the serum VEGF concentration was increased in ASO and TAO patients, but increased concentration of M-CSF was seen only in ASO patients. These results may reflect a difference between ASO and TAO in disease pathogenesis.     

Benefits of exercise therapy in peripheral arterial disease

Peripheral arterial disease (PAD) is a common disorder caused largely by atherosclerosis. Although it is associated with increased morbidity and cardiovascular mortality, PAD remains underdiagnosed. Traditional PAD care has involved cardiovascular risk factor modification, use of antiplatelet agents, and revascularization. For those individuals who are eligible and willing to perform exercise therapy (ET), a significant benefit may be recognized. Despite this, ET faces several challenges to implementation. Notably, the lack of reimbursement by third party payers remains the major challenge to routine use of ET.     

Treating liver cirrhosis in dogs with hepatocyte growth factor gene therapy via the hepatic artery

Background/purpose

Liver cirrhosis, an irreversible result of chronic liver disease, has had no effective therapy except liver transplantation. We previously reported successful therapy of liver cirrhosis in rats using the hepatocyte growth factor gene. We presently performed hepatocyte growth factor gene therapy in dogs with liver cirrhosis to examine the feasibility for clinical use.

Methods

Liver cirrhosis was established in beagles by administrating dimethylnitrosamine. Naked human hepatocyte growth factor gene or naked LacZ gene was injected repeatedly into livers via the hepatic artery using a porter catheter in dogs with cirrhosis.

Results

Human hepatocyte growth factor gene expression was detected in livers by immunohistochemical staining and an enzyme-linked immunosorbent assay. Serum liver function test results improved with hepatocyte growth factor gene therapy, which also inhibited hepatic transforming growth factor-β1expression and reversed fibrosis in cirrhotic liver, improving survival of the dogs.

Conclusion

As naked hepatocyte growth factor gene therapy via the hepatic artery proved simple, safe, and effective in larger animals with cirrhosis, this therapy may be clinically applicable.     

Therapeutic angiogenesis induced by hepatocyte growth factor: potential gene therapy for ischemic diseases.

Recent progress in molecular biology has led to the development of gene therapy as a new strategy to treat a variety of cardiovascular diseases. Targeted diseases range from single gene deficiency diseases to more complex diseases in adults such as restenosis after angioplasty. One obvious major target in the field of gene therapy is ischemic diseases such as myocardial infarction, angina and peripheral arterial diseases (i.e. ASO (arteriosclerosis obliterans)). In a large proportion of such patients, the anatomical extent and the distribution of arterial occlusive disease make the patients unsuitable for operative or percutaneous revascularization. Thus, the disease frequently follows an inexorable downhill course. Of importance, there is no optimal medical therapy for severe ischemic hearts and critical ischemic limbs. Therefore, novel therapies are required to treat these patients. Recently, the efficacy of therapeutic angiogenesis using VEGF (vascular endothelial growth factor) gene transfer has been reported in human patients with critical limb ischemia and myocardial ischemia. Thus, the strategy for therapeutic angiogenesis using angiogenic growth factors should be considered for the treatment of patients with critical limb ischemia or myocardial infarction. The endothelial cell specificity of VEGF has been considered to be an important advantage for therapeutic angiogenesis, as endothelial cells represent the critical cellular element responsible for new vessel formation. Indeed, human gene therapy for ASO and angina has already begun in the USA, with surprising and beneficial effects. We have focused on hepatocyte growth factor (HGF), which is a mesenchyme-derived pleiotropic factor that regulates cell growth, cell motility, and morphogenesis in various types of cells. Recently, HGF is also considered to be a powertul growth tactor for endothelial cells. In this review, we described the potential gene therapy for ischemic diseases using HGF.