By promoting angiogenesis, it is possible to treat occlusive arterial diseases, arteriosclerosis obliterans and Buerger disease, as well as ischemic heart diseases and cerebral diseases such as angina, myocardial infarction and cerebral infarction (Non-patent documents 1 to 7).
It is estimated that dangerous ischemia of extremities occurs annually in 500 to 1000 persons per million. The majority of these patients cannot be treated by a surgery or transdermal revascularization because arterial occlusion spreads over a broad site. Accordingly, new therapies, such as angiogenesis are expected to become important in treating such patients. A number of proteins are known to promote angiogenesis, including HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor) (Patent document 1 and 2). However, VEGF is disadvantageous in that it easily generates edema. A method of introducing a gene for increasing the level of endogenous VEGF in patients with dangerous ischemia of extremities or myocardial ischemia has been studied. However, VEGF therapy for these patients may cause limb edema as a side-effect of the therapy. Blood-brain barrier leakage in the ischemic brain due to VEGF is also reported. HGF increases the ability of cells to migrate upon administration thereof, but is disadvantageous in that where cancer occurs, there is a risk of inducing the metastasis of the cancer. Accordingly, there is need for a novel polypeptide for the treatment of occlusive arterial diseases, arteriosclerosis obliterans and Buerger disease, as well as ischemic heart diseases and cerebral diseases such as angina, myocardial infarction and cerebral infarction.    Patent document 1: Japanese National Phase PCT Laid-Open Publication No. 10-51071    Patent document 2: Japanese National Phase PCT Laid-Open Publication No. 2001-517075    Non-patent document 1: KEKKAN SHINSEI RYOHO-KISO TO RINSYO—(Angiogenesis Therapy—Fundamental and Clinical-), edited by Yasumi Uchida & Yutaka Kozuka, Medical Book Publication Department in Shinko Trading Co., Ltd., May 25, 1997;    Non-patent document 2: The FASEB J. 17 779-781, 2003    Non-patent document 3: Circulation 97, 1114-1123, 1998    Non-patent document 4: The Lancet, 348, 370-374, 1996    Non-patent document 5: Circulation 105, 1491-96, 2002    Non-patent document 6: Gene Therapy 7, 417-427, 2000    Non-patent document 7: Circulation 109, 424-431, 2004