Heart Vessels. 2016 May;31(5):713-21. 

Safety and efficacy of sustained release of basic fibroblast growth factor using gelatin hydrogel in patients with critical limb ischemia.  

Kumagai M1, Marui A2,3, Tabata Y4, Takeda T1,3, Yamamoto M4, Yonezawa A5, Tanaka S6,7, Yanagi S8, Ito-Ihara T9, Ikeda T3, Murayama T9, Teramukai S10, Katsura T5, Matsubara K5, Kawakami K6,7, Yokode M9, Shimizu A3, Sakata R1.


1Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.

2Division of Cardiovascular Surgery, Tenri Hospital, Nara, Japan.

3Department of Experimental Therapeutics, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan.

4Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.

5Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.

6Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan.

7Department of Data Science, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan.

8Department of Cardiovascular Surgery, Kumamoto Central Hospital, Kumamoto, Japan.

9Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan.

10Department of Biostatistics, Kyoto Prefectural University of Medicine, Kyoto, Japan.



As a form of therapeutic angiogenesis, we sought to investigate the safety and efficacy of a sustained-release system of basic fibroblast growth factor (bFGF) using biodegradable gelatin hydrogel in patients with critical limb ischemia (CLI). We conducted a phase I-IIa study that analyzed 10 CLI patients following a 200-μg intramuscular injection of bFGF-incorporated gelatin hydrogel microspheres into the ischemic limb. Primary endpoints were safety and transcutaneous oxygen pressure (TcO2) at 4 and 24 weeks after treatment. During the follow-up, there was no death or serious procedure-related adverse event. After 24 weeks, TcO2 (28.4 ± 8.4 vs. 46.2 ± 13.0 mmHg for pretreatment vs after 24 weeks, p < 0.01) showed significant improvement. Regarding secondary endpoints, the distance walked in 6 min (255 ± 105 vs. 318 ± 127 m, p = 0.02), the Rutherford classification (4.4 ± 0.5 vs. 3.1 ± 1.4, p = 0.02), the rest pain scale (1.7 ± 1.0 vs. 1.2 ± 1.3, p = 0.03), and the cyanotic scale (2.0 ± 1.1 vs. 0.9 ± 0.9, p < 0.01) also showed improvement. The blood levels of bFGF were within the normal range in all patients. A subanalysis of patients with arteriosclerosis obliterans (n = 7) or thromboangiitis obliterans (Buerger’s disease) (n = 3) revealed that TcO2 had significantly improved in both subgroups. TcO2 did not differ between patients with or without chronic kidney disease. The sustained release of bFGF from biodegradable gelatin hydrogel may offer a safe and effective form of angiogenesis for patients with CLI.

PMID: 25861983



Peripheral arterial disease (PAD), such as atherosclerosis obliterans (ASO) or thromboangiitis obliterans (TAO) (Buerger’s disease), is characterized by reduced blood flow to the limbs which induces critical limb ischemia (CLI) in severe cases. It is reported that approximately 40 % of patients with CLI eventually lose their legs within 6 months, and the mortality rate is up to 20 % [1]. For CLI patients resistant to conventional therapies, therapeutic angiogenesis (i.e., the administration of growth factors, gene therapy or cell transplantation) is thought to be a new therapeutic strategy aimed to improve the blood perfusion to the ischemic vascular beds that helps to reduce the tissue damage and necrosis.



Figure 1. Schematic diagram of the study



Basic fibroblast growth factor (bFGF) is known to promote proliferation of mesenchymal cells and potently induce neovascularization which holds potential for the therapeutic angiogenesis. However, short biological half-life of bFGF in the body hampers the clinical application. To overcome the problem, we have developed a new drug delivery system (DDS) using a biodegradable acidic gelatin hydrogel [2]. Gelatin is a water-soluble biopolymer originating from collagen and has been clinically used in various applications because of its non-toxic nature. bFGF-incorporated gelatin hydrogel gradually releases bFGF in the body after administration which serves as a novel DDS which enables long-lasting local release of bFGF at the injected site. We have previously demonstrated the effectiveness of bFGF-incorporated gelatin hydrogel in various animal models [3]. In the present open-labeled clinical study, we validated the safety and effectiveness of the bFGF-incorporated gelatin hydrogel in CLI patients (Figure 1).


Figure 2. Changes of TcO2. **p<0.01.

A total of 10 patients were enrolled in this study (66.9 ± 12.2 years old, seven males). Among them, seven patients were diagnosed as ASO and the others as TAO. The bFGF-incorporated gelatin hydrogel microspheres (200 µg of bFGF) were injected into the gastrocnemius muscle of the unilateral ischemic limb and the patients were followed for 24 weeks. There was no death or procedure-related adverse events attributable to topical use of the sustained-release bFGF. The treatment did not induce focal inflammation or edema at the injection site. The blood concentration of bFGF after treatment was undetectable or within the normal value in all patients. There were two serious adverse events requiring hospitalization that occurred in the same patient (cellulitis; 18 weeks after treatment, intracranial hemorrhage; 24 weeks after treatment). Neither of these adverse events was thought to be related to the bFGF treatment. Although there were transient elevations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), C-reactive protein, creatine phosphokinase, or creatinine in 4 patients, these values returned to the normal range without further treatment. TcO2 (tissue oxygen pressure; 28.4 ± 8.4 mmHg at pretreatment) showed a significant improvement at both 4 weeks (42.8 ± 10.3 mmHg, p < 0.01) and 24 weeks (46.2 ± 13.0 mmHg, p < 0.01) after treatment (Figure 2). The distance walked in 6 min significantly increased at both 4 weeks (p < 0.01) and 24 weeks (p = 0.02) compared to pretreatment values. Rutherford classification improved in 6 patients, and no patient worsened at 4 and 24 weeks after treatment. The skin ulcer disappeared in 1 out of 4 patients who exhibited intractable ulcer before treatment, and ischemic rest pain disappeared in 4 out of 10 patients at 24 weeks after treatment.

There are 500 to 1000/million/year new cases of CLI in Europe and North American countries, and the incidence of major amputations is reported to be 120 to 500/million/year [1]. Among CLI patients, approximately 20 % are not indicated for percutaneous transluminal angioplasty or surgical revascularization because of the severity or diffuse arteriosclerotic lesion [4]. In the present study, we have indicated the safety and therapeutic potential of bFGF-incorporated gelatin hydrogel in clinical settings which may provide an additional therapeutic option for the patients with severe CLI. Further clinical investigations are required for the broad application of this therapeutic modality.



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  2. Tabata Y, Hijikata S, Ikada Y (1994) Enhanced vascularization and tissue granulation by basic fibroblast growth factor impregnated in gelatin hydrogels. J Control Release 31:189–199.
  3. Doi K, Ikeda T, Marui A, Kushibiki T, Arai Y, Hirose K, Soga Y, Iwakura A, Ueyama K, Yamahara K, Itoh H, Nishimura K, Tabata Y, Komeda M (2007) Enhanced angiogenesis by gelatin hydrogels incorporating basic fibroblast growth factor in rabbit model of hind limb ischemia. Heart Vessels 22:104–108.
  4. Marston WA, Davies SW, Armstrong B, Farber MA, Mendes RC, Fulton JJ, Keagy BA (2006) Natural history of limbs with arterial insufficiency and chronic ulceration treated without revascularization. J Vasc Surg 44:108–11.


Acknowledgements: This work was supported by Health Labour Sciences Research Grant, Japan (No. 851110600024).



Hidetoshi Masumoto, M.D., Ph.D.

Director of Research Division

Assistant Professor

Department of Cardiovascular Surgery, Kyoto University

54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan





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