Potential Role of Hepatocyte Growth Factor, a Novel Angiogenic Growth Factor, in Peripheral Arterial Disease : Downregulation of HGF in Response to Hypoxia in Vascular Cells

Abstract

Background-Although hepatocyte growth factor (HGF), a novel angiogenic growth factor, plays an important role in angiogenesis, regulation of local HGF production under hypoxia has not yet been clarified in vascular smooth muscle cells (VSMC) and endothelial cells (EC). Thus, we have studied the role of HGF in hypoxia-induced endothelial injury and the regulation of local vascular HGF expression in response to hypoxia. Methods and Results-HGF attenuated hypoxia-induced endothelial cell death. Importantly, hypoxic treatment of EC resulted in a significant decrease in local HGF production according to the severity of hypoxia and increased VEGF. Similarly, hypoxia significantly decreased in mRNA and protein of HGF and increased VEGF production in VSMC. In organ culture system, local HGF production was also significantly decreased by hypoxia (PϽ0.01). Downregulation of HGF by hypoxia is due to a significant decrease in cAMP, as hypoxic treatment decreased cAMP, a stimulator of HGF. Although active TGF-␤, a suppressor of HGF, was increased at 72 hours after hypoxic treatment, treatment of anti-TGF-␤ antibody did not attenuate decreased HGF production. Finally, rHGF was intra-arterially administered into unilateral hind limb ischemia rabbits, to evaluate in vivo angiogenic activity. Of importance, a single intra-arterial administration of rHGF reduced severe necrosis due to ischemia in rabbit muscle, accompanied by a significant increase in angiographic score (PϽ0.01). Conclusions-Overall, these data demonstrated that hypoxic treatment of vascular cells significantly downregulated HGF production due to decreased cAMP, suggesting their potential roles in the pathophysiology of ischemic diseases. Moreover, administration of rHGF induced therapeutic angiogenesis, accompanied by improvement of necrotic changes in the ischemic hind limb model, as cytokine supplement therapy for peripheral arterial disease. (Circulation. 1999;100[suppl II]:II-301-II-308.

Development of safe and efficient novel nonviral gene transfer using ultrasound: enhancement of transfection efficiency of naked plasmid DNA in skeletal muscle

“…12,42,43 Briefly, male New Zealand White rabbits (3.5 to 4.0 kg) (Kitayama Rabes, Kyoto, Japan) were used. Four separate injections of 250 g human HGF vector (total 1 mg) locally (intramuscularly into the pretibial muscle of ischemic limb) were performed approximately 2-4 cm below the skin.…”

“…12,42,43 Briefly, morphometric analysis of collateral vessel development in the ischemic limb was performed in 4-s angiograms recorded after injection of contrast medium into the internal iliac artery. A grid with 20-mm spaces was placed over the angiogram in the region of the medial thigh.…”

“…12,42,43 The film selected for analysis was scanned with a high resolution video camera; the signal produced by the video camera was digitized and displayed on a video monitor (Laser Scan Image Comm, Santa Clara, CA, USA). Center-lines were traced manually for a 10-mm long segment beginning immediately distal to the tip of the Doppler wire.…”

“…The pulse of the posterior tibial artery was identified using a Doppler probe, and the systolic blood pressure in both limbs was determined using standard techniques. 12,42,43 The calf blood pressure ratio for each rabbit was defined as the ratio of systolic pressure of the ischemic limb to that of the normal limb.…”

Effect of nifedipine on endothelial function in normotensive smokers: potential contribution of increase in circulating hepatocyte growth factor

“…27 These data, including the present findings, are consistent with our previous in vitro findings that the downregulation of HGF is caused by downregulated c-AMP and/or upregulated TGF-b in a hypoxic or high glucose condition which promotes atherosclerosis, and addition of HGF could rescue endothelial cells from death. 28,29 Therefore, supplemental HGF would physiologically improve endothelial dysfunction of vessels induced by smoking. Since the serum HGF level was increased approximately two-fold by nifedipine, it is considered to be effective for vascular tissue and endothelial cells.…”