A basic fibroblast growth factor analog for protection and mitigation against acute radiation syndromes

The effects of fibroblast growth factors and their potential as broad-spectrum agents to treat and mitigate radiation injury have been studied extensively over the past two decades. This report shows that a peptide mimetic of basic fibroblast growth factor (FGF-P) protects and mitigates against acute radiation syndromes. FGF-P attenuates both sepsis and bleeding in a radiation-induced bone marrow syndrome model and reduces the severity of gastrointestinal and cutaneous syndromes; it should also mitigate combined injuries. FGF-2 and FGF-P induce little or no deleterious inflammation or vascular leakage, which distinguishes them from most other growth factors, angiogenic factors, and cytokines. Although recombinant FGFs have proven safe in several ongoing clinical trials, they are expensive to synthesize, can only be produced in limited quantity, and have limited shelf life. FGF-P mimics the advantageous features of FGF-2 without these disadvantages. This paper shows that FGF-P not only has the potential to be a potent yet safe broad-spectrum medical countermeasure that mitigates acute radiotoxicity but also holds promise for thermal burns, ischemic wound healing, tissue engineering, and stem-cell regeneration.

Intrathecal epidermal growth factor and fibroblast growth factor-2 exacerbate meningeal proliferative lesions associated with intrathecal catheters

OBJECTIVE

There is evidence that promoting the proliferation of endogenous neural stem cells in the spinal cord could be an effective strategy in the treatment of spinal cord injury. We studied this proliferation in a minimal injury rat model in the presence of epidermal growth factor and fibroblast growth factor-2.

METHODS

Adult female Sprague Dawley rats were minimally injured at T8 and received the growth factors intrathecally by osmotic pump for either 3, 7, or 14 days beginning immediately after spinal cord injury. The infusions were made through a subarachnoid catheter connected to an osmotic minipump. Beginning at the time of injury, the rats received daily bromodeoxyuridine to label proliferating cells for determination of the labeling index.

RESULTS

Significant differences were found in the labeling index between injured and non-injured rats. We concluded that minimal spinal cord injury from the stab injury and from the catheter itself increased the proliferation of ependymal region stem/progenitor cells. A minority (23.3%) of the rats developed proliferative lesions in association with the catheters alone, but the lesions were significantly larger and occurred in almost all (93.8%) rats receiving the mitogens, resulting in marked spinal cord compression.

CONCLUSION

The large proliferative growths in the epidermal growth factor and fibroblast growth factor-2-treated rats were unexpected and are indicative of the major effects of these mitogens. This suggests that considerable caution is required in devising therapeutic strategies directed toward mitogenic stimulation by growth factors delivered into the subarachnoid space. Further study is required to determine the appropriate and safe dosage of mitogens for potential use in spinal cord repair.

Local application of recombinant human fibroblast growth factor-2 on bone repair: a dose-escalation prospective trial on patients with osteotomy

Based on preclinical evidence in animal models, the present study examined the clinical efficacy and safety of recombinant human fibroblast growth factor-2 (rhFGF-2) to accelerate bone repair in a dose-escalation prospective trial. One of three dosages (200, 400 or 800 microg) of rhFGF-2 in a biodegradable gelatin hydrogel was injected during surgery into the osteotomy site of 59 knee osteoarthritis patients undergoing high tibial osteotomy, and 57 of them were monitored for 16 weeks. The rhFGF-2 dose dependently increased the percentage of patients with radiographic bone union, and decreased the average time needed for such union. The percentages of patients with an absence of pain and full-weight bearing were also greater in the higher dosage groups than in the low dosage group, especially in the clinically critical periods 6, 8, and 10 weeks. Neither blood chemistries nor clinical adverse events were associated with the rhFGF-2 dosages. We therefore conclude that the rhFGF-2 in gelatin hydrogel dose dependently accelerated radiographic bone union of a surgical osteotomy with a safety profile at least at the dosages used, suggesting the clinical efficacy of this agent for bone repair.

Local application of basic fibroblast growth factor increases the risk of local infection after trauma: an in-vitro and in-vivo study in rats

INTRODUCTION

Local application of growth factors to stimulate wound and fracture healing is attracting increasing interest. We studied the effect of local application of a potent angiogenic growth factor, basic fibroblast growth factor (bFGF), on resistance to local infection after soft tissue trauma.

METHODS

For in-vitro and in-vivo experiments, we used recombinant human bFGF. The in-vitro investigations were performed by isolation of human leukocyte fractions, cytokine analysis, phagocytosis assay, flow cytometry, and LDH assay. For the in-vivo investigation, a paired comparison of infection rates was carried out on Sprague-Dawley rats after standardized, closed soft tissue trauma and local, percutaneous bacterial inoculation of different concentrations of Staphylococcus aureus (2 x 10(4) to 2 x 10(7) colony-forming units (cfu)). The lower leg was treated with 1, 10 or 100 ng bFGF (16 animals for each concentration) and without bFGF (16 animals).

RESULTS

Cytotoxic reactions due to the concentrations of bFGF used could be excluded in the in-vitro tests since incubations of isolated peripheral blood mononuclear cells (PBMCs) with increasing concentrations of bFGF for 24 h did not lead to an increase in the release of lactate dehydrogenase in the culture supernatants compared to corresponding control incubations without any bFGF added. A significant increase in cytokine release was observed after the co-incubation of PBMCs with 100 or 200 ng of the same bFGF that was used for the animal experiments. Furthermore, the capacity of phagocytes in whole blood to phagocytose bacteria was suppressed in the presence of 100 ng exogenously added bFGF. We found continuously reduced granulocytic phagocytosis in FGF-supplemented blood compared to non-supplemented blood. In the in-vivo investigation, the infection rate for the group without bFGF was 0.25. In the groups with 1, 10 and 100 ng bFGF, the infection rates were 0.5, 0.7 and 0.8, respectively. A dose-dependent increase in infection rate was observed after local application of bFGF, compared to the untreated control group. The difference in infection rates for the groups in which 10 and 100 ng bFGF was used, relative to the group without bFGF, was statistically significant.

INTERPRETATION

If these initial results are confirmed for other potent angiogenic growth factors, then the local use of growth factors for stimulation of wound and bone healing--a main focus of current research in traumatology--will have to be reconsidered and preceded with a strict evaluation of the risks and benefits.

Raman imaging demonstrates FGF2-induced craniosynostosis in mouse calvaria

Craniosynostosis is a severe craniofacial disease where one or more sutures, the fibrous tissue that lies between the cranial bones, fuses prematurely. Some craniosynostosis syndromes are known to be caused by mutations in fibroblast growth factor (FGF) receptors. Mutated FGF receptors are thought to cause constitutive signaling. In this study, heparin acrylic beads released fibroblast growth factor 2 (FGF2) to mimic constitutive signaling by mutated receptors, delivering FGF2 in addition to already existing normal tissue amounts. Fetal day 18.5 mouse sutures were treated with FGF2-soaked beads and cultured in serum free media for 48 h. We have shown previously that this treatment leads to fusion and increased Msx2 expression, but here we use near-infrared Raman imaging to simultaneously examine the mineral components and matrix components of cranial tissue while providing light microscopic spatial information. FGF2-treated mouse sutures show increased v1 phosphate and v1 carbonate bandwidths, indicating a slightly chemically modified mineral being rapidly deposited. In addition, FGF2-treated mouse sutures show a marked increase in mineral-to-matrix ratios compared to control mouse sutures, typical of increased mineralization.

Therapeutic angiogenesis with recombinant fibroblast growth factor-2 for intermittent claudication (the TRAFFIC study): a randomised trial

BACKGROUND

Recombinant fibroblast growth factor-2 (rFGF-2) improves perfusion in models of myocardial and hindlimb ischaemia. We investigated whether one or two doses of intra-arterial rFGF-2 improves exercise capacity in patients with moderate-to-severe intermittent claudication.

METHODS

190 patients with intermittent claudication caused by infra-inguinal atherosclerosis were randomly assigned (1:1:1) bilateral intra-arterial infusions of placebo on days 1 and 30 (n=63); rFGF-2 (30 microg/kg) on day 1 and placebo on day 30 (single-dose, n=66); or rFGF-2 (30 microg/kg) on days 1 and 30 (double-dose, n=61). Primary outcome was 90-day change in peak walking time. Secondary outcomes included ankle-brachial pressure index and safety. The main analysis was per protocol.

FINDINGS

Before 90 days, six patients had undergone peripheral revascularisation and were excluded, and ten withdrew or had missing data. 174 were therefore assessed for primary outcome. Peak walking time at 90 days was increased by 0.60 min with placebo, by 1.77 min with single-dose, and by 1.54 min with double-dose. By ANOVA, the difference between groups was p=0.075. In a secondary intention-to-treat analysis, in which all 190 patients were included, the difference was p=0.034. Pairwise comparison showed a significant difference between placebo and single-dose (p=0.026) but placebo and double-dose did not differ by much (p=0.45). Serious adverse events were similar in all groups.

INTERPRETATION

Intra-arterial rFGF-2 resulted in a significant increase in peak walking time at 90 days; repeat infusion at 30 days was no better than one infusion. The findings of TRAFFIC provide evidence of clinical therapeutic angiogenesis by intra-arterial infusion of an angiogenic protein.

Pharmacological treatment of coronary artery disease with recombinant fibroblast growth factor-2: double-blind, randomized, controlled clinical trial

BACKGROUND

Single-bolus intracoronary administration of fibroblast growth factor-2 (FGF2) improved symptoms and myocardial function in a phase I, open-label trial in patients with coronary artery disease. We conducted the FGF Initiating RevaScularization Trial (FIRST) to evaluate further the efficacy and safety of recombinant FGF2 (rFGF2).

METHODS AND RESULTS

FIRST is a multicenter, randomized, double-blind, placebo-controlled trial of a single intracoronary infusion of rFGF2 at 0, 0.3, 3, or 30 microg/kg (n=337 patients). Efficacy was evaluated at 90 and 180 days by exercise tolerance test, myocardial nuclear perfusion imaging, Seattle Angina Questionnaire, and Short-Form 36 questionnaire. Exercise tolerance was increased at 90 days in all groups and was not significantly different between placebo and FGF-treated groups. rFGF2 reduced angina symptoms as measured by the angina frequency score of the Seattle Angina Questionnaire (overall P=0.035) and the physical component summary scale of the Short-Form 36 (pairwise P=0.033, all FGF groups versus placebo). These differences were more pronounced in highly symptomatic patients (baseline angina frequency score < or =40 or Canadian Cardiovascular Society score of III or IV). None of the differences were significant at 180 days because of continued improvement in the placebo group. Adverse events were similar across all groups, except for hypotension, which occurred with higher frequency in the 30-microg/kg rFGF2 group.

CONCLUSIONS

A single intracoronary infusion of rFGF2 does not improve exercise tolerance or myocardial perfusion but does show trends toward symptomatic improvement at 90 (but not 180) days.

Pharmacokinetics and pharmacodynamics of recombinant FGF-2 in a phase I trial in coronary artery disease

Fibroblast growth factor-2 (FGF-2) is a heparin-binding protein capable of inducing angiogenesis in multiple animal models of chronic ischemia. The pharmacokinetics and pharmacodynamics of a single dose of recombinant FGF-2 (rFGF-2) administered by intracoronary or intravenous infusion were evaluated in a Phase I trial in 66 patients with severe coronary artery disease. rFGF-2 displayed biphasic elimination with a mean studywide distribution t1/2 of 21 minutes and a mean apparent terminal elimination t1/2 of 7.6 hours. Systemic exposure to rFGF-2 was comparable following intracoronary or intravenous administration. Peak plasma concentration and area under the concentration-time curve increased proportionally with dose, indicating linear pharmacokinetics over the dose range examined (0.33 to 48.0 micrograms/kg). Greater systemic exposure was observed when heparin was administered closer to rFGF-2 infusion, consistent with slower clearance of heparin/rFGF-2 complexes. Infusion of rFGF-2 was associated with changes in acute hemodynamics. While a clear PK/PD dose-response relationship was not established, a trend toward hypotension and tachycardia with higher rFGF-2 doses was observed.

Therapeutic interventions for enhancing collateral development by administration of growth factors: basic principles, early results and potential hazards

The importance of spontaneously developing collateral vessels to supplement perfusion of tissue rendered ischemic by vascular obstruction was recognized many years ago. However, it was not until potent angiogenesis factors were identified, purified, and produced in sufficient quantities, that the field began its rapid development. In the early 1990s it was first shown that basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) proteins could actually stimulate collateral flow. However, additional studies also demonstrated that the duration of exposure of the vessels to angiogenesis factors was critical, and that the administration of proteins, with their relatively brief half-lives, may pose important practical limitations. The demonstration that gene therapy can improve collateral function presents one of the solutions to the conundrum, since gene therapy can be considered a sophisticated form of a sustained delivery system. The results of several clinical trials have been reported. All involve administration of single angiogenesis agents, and most are Phase I trials. The two studies rising to Phase II status demonstrated no treatment effect on the primary end-point. It may therefore be relevant to consider that the molecular mechanisms responsible for angiogenesis are extraordinarily complex, and an optimal angiogenesis intervention may require a 'multiple factor' strategy. It is important to note that no serious side-effects ascribable to an angiogenesis agent were recognized in these trials. However, angiogenesis agents are potent molecules with multiple activities. It is therefore possible that they might occasionally cause side-effects, some serious. Among these, based on their biologic activities, are neovascularization of non-targeted tissues, expansion and induction of instability of atherogenic plaque, and growth of tumors. In summary, there is ample experimental evidence justifying an optimistic outlook relating to our eventually being successful in enhancing collateral flow to ischemic tissue in a clinical setting. However, we are not there yet, and identification of the optimal angiogenesis strategy is still unclear. Additional experimental work, in parallel with large, carefully controlled clinical trials are needed to continue the exciting advances of the last decade, and to achieve the goal of providing patients with alternative potent therapies to improve collateral flow, and thereby to alleviate their symptoms and perhaps to prolong their lives.

Simultaneous elevation in the serum concentrations of the angiogenic growth factors VEGF and bFGF is an independent predictor of poor prognosis in non-Hodgkin lymphoma: a single-institution study of 200 patients

High serum concentrations of vascular endothelial growth factor (S-VEGF) and basic fibroblast growth factor (S-bFGF) are associated with unfavorable clinical characteristics in cancer. The combined effect of S-VEGF and S-bFGF on the survival of 200 patients with non-Hodgkin lymphoma (NHL) was studied. High S-VEGF and S-bFGF at diagnosis were associated with poor survival with the medians, the highest tertiles, or the highest quartiles as the cutoff values. The highest prognostic power was obtained when S-VEGF and S-bFGF were examined as a combination. Patients who had both S-VEGF and S-bFGF within the highest quartiles had only a 21% 5-year survival rate in contrast to a 64% 5-year survival rate among patients with both factors within the 3 lowest quartiles (P <.0001). Simultaneous elevation of S-VEGF and S-bFGF was associated with poor survival in different grades of lymphomas and in the largest histologic subgroup, the large-cell diffuse and immunoblastic lymphomas. S-VEGF (relative risk [RR], 1.83; P =.019) and S-bFGF (RR, 2.02; P =.0049) had independent influences on survival in multivariate models when tested together with the components of the International Prognostic Index (IPI). Patients with both S-VEGF and S-bFGF within the highest quartiles had nearly 3 times higher risk for death (RR, 2.90; 95% confidence interval [CI], 1.56-5.40; P =.0008) than the rest of the patients. This RR was higher than the relative risks associated with any of the components of the IPI in the same model. The authors conclude that the combination of S-VEGF and S-bFGF is a powerful prognostic variable in NHL. (Blood. 2000;96:3712-3718)

Clinical trials in coronary angiogenesis: issues, problems, consensus: An expert panel summary

The rapid development of angiogenic growth factor therapy for patients with advanced ischemic heart disease over the last 5 years offers hope of a new treatment strategy based on generation of new blood supply in the diseased heart. However, as the field of therapeutic coronary angiogenesis is maturing from basic and preclinical investigations to clinical trials, many new and presently unresolved issues are coming into focus. These include in-depth understanding of the biology of angiogenesis, selection of appropriate patient populations for clinical trials, choice of therapeutic end points and means of their assessment, choice of therapeutic strategy (gene versus protein delivery), route of administration, and the side effect profile. The present article presents a summary statement of a panel of experts actively working in the field, convened by the Angiogenesis Foundation and the Angiogenesis Research Center during the 72nd meeting of the American Heart Association to define and achieve a consensus on the challenges facing development of therapeutic angiogenesis for coronary disease.

Effects of a single intracoronary injection of basic fibroblast growth factor in stable angina pectoris

We sought to evaluate safety, tolerability, pharmacokinetics, and pharmacodynamics of basic fibroblast growth factor (bFGF), administered as a single intracoronary injection, to subjects with stable angina pectoris secondary to coronary artery disease. bFGF, an angiogenic growth factor, has been shown to enhance collateral development in animal models of progressive coronary occlusion. To our knowledge, this study represents the initial introduction of parenteral bFGF into humans. This was a phase 1, randomized, dose-escalation trial of bFGF in 25 subjects with coronary artery disease and stable angina. Subjects were randomized 2:1 to a single dose of bFGF or placebo, injected into the left main coronary artery. bFGF doses ranged from 3 to 100 microg/kg, increasing in half-log increments. bFGF was generally well tolerated at doses of 3 to 30 microg/kg. Plasma clearance was 20 +/- 2 ml/kg/min, with an elimination half-life of 85 +/- 11 minutes. bFGF caused acute hypotension ( approximately 10%) that did not appear to be dose-related through the dose range studied. Of the 9 subjects who received 30 to 100 microg/kg bFGF, 2 had sustained hypotension, mild to moderate in severity, lasting 1 to 3 days, and 3 subjects developed bradycardia hours to days after bFGF administration. bFGF dilated epicardial coronary arteries (7.4 +/- 2.5% mean diameter increase, p <0.02). Transient mild thrombocytopenia and proteinuria were observed in some subjects in the 30-microg/kg cohort. No subject had signs suggesting systemic angiogenesis. Thus, intracoronary bFGF, at doses of 3 to 30 microg/kg, was generally well tolerated in subjects with stable angina.

Delivery strategies to achieve therapeutic myocardial angiogenesis

The use of recombinant genes or growth factors to enhance myocardial collateral blood vessel function may represent a new approach to the treatment of cardiovascular disease. Proof of concept has been demonstrated in animal models of myocardial ischemia, and clinical trials are underway. Currently, it is unknown which is the safest and most effective delivery strategy to induce clinically important therapeutic angiogenic responses in ischemic myocardium. Most strategies for transcatheter delivery of angiogenic factors have used an intracoronary route, which may have limitations because of imprecise localization of genes or proteins and systemic delivery to noncardiac tissue. The effect of direct intraoperative intramyocardial injection of angiogenic factors on collateral function has been reported in experimental models, and angiogenesis is being studied after direct intramyocardial injection of angiogenic peptides or plasmid vectors during open heart surgery in patients. Catheter-based transendocardial injection of angiogenic factors may provide equivalent benefit without the need for surgery. Intrapericardial delivery of angiogenic factors may offer a theoretical advantage of prolonged exposure of either coronary or myocardial tissue to the administered drug as result of a reservoir function of the pericardium. In this article, we review the different modes of administration for therapeutic myocardial angiogenesis therapy.

Teratogenic effects of implanting fibroblast growth factor-2-soaked beads in the cardiac region of the stage 24 chick embryo

The identification of fibroblast growth factor-2 (FGF-2), and other family members, in a variety of embryonic tissue extracts has implicated these growth factors as participants in many embryonic events, including cardiogenesis. The present study was conducted in an attempt to characterize the effects of exogenous FGF-2 on the development of the avian heart. Heparin acrylic beads, each soaked in 100 micrograms/ml FGF-2, were applied to the Hamburger and Hamilton [(1951) J. Morphol. 88:49-92] stage 24 (day 4 of incubation) chick heart, near the primitive ventricle. The embryos were allowed to develop until stage 41 (day 15), at which time they were observed for the presence of gross external and internal anomalies. Crown rump length (CRL), wet weight (WW), and various heart measurements were obtained and compared. The survival rate of the control group was significantly higher (P < 0.05) than that for the experimental group and the anomaly rate for the control group was significantly lower (P < 0.01) than that for the experimental group. The experimental group exhibited a wide range of anomalies, most of which were cardiac in nature; however, anomalies of the ventral thoracoabdominal wall were also noted. Our data suggest that application of exogenous FGF-2 has teratogenic effects on cardiac development as well as on the development of the ventral body wall of the avian embryo.

Fibroblast growth factor 2, heparin and suramin reduce epithelial ulcer development in experimental HSV-1 keratitis

BACKGROUND

We have previously shown that basic fibroblast growth factor (FGF-2) enhances corneal epithelial healing in different experimental models in vivo. In order to study the healing effect of this growth factor in pathological conditions of the cornea, we investigated whether topical application of FGF-2 could affect herpes keratitis in rabbits. Since HSV-1 infection is prevented in vitro by incubation with heparin, we also topically applied heparin and suramin, considering the similar interaction of herpes simplex virus and FGF-2 with cell membrane-anchored heparan sulfate.

METHODS

After virus inoculation with a human BEY.2 strain, rabbits were treated with either FGF-2 (200 ng to 2 micrograms/application), heparin (250 micrograms/application) or suramin (250 micrograms/application) 4 times daily until day 14. Acyclovir and placebo administrations served as controls (n = 48 rabbits). Computerized ulcer surface analysis, clinical observations and virus recovery assays were performed.

RESULTS

Topical FGF-2, heparin and suramin treatment revealed a significant reduction in peak ulcer sizes, and complete epithelial healing was achieved earlier than in placebo-treated corneas. However, no significant antiviral effect of FGF-2, heparin and suramin was detectable in plaque assays from conjunctival swabs.

CONCLUSIONS

These experiments demonstrate that FGF-2 is effective in promoting herpetic epithelial ulcer healing, either due to its proliferative effects on epithelial cells or indirectly by occupying the sites on cell surface heparan sulfate necessary for the attachment of the virion. The latter mechanism of action is presumably the reason for the similar effect of heparin and suramin.

Recombinant mitotoxin basic fibroblast growth factor-saporin reduces venous anastomotic intimal hyperplasia in the arteriovenous graft

BACKGROUND

The plant cytotoxin saporin (SAP) is a potent ribosome-inactivating protein. When conjugated to basic fibroblast growth factor (FGF2), it selectively kills proliferating cells that have upregulated FGF receptors. In this study, we evaluated the effect of the recombinant chimeric mitotoxin rFGF2-SAP on venous anastomotic intimal hyperplasia, a major cause of failure of arteriovenous (AV) grafts.

METHODS AND RESULTS

Recently designed expanded polytet-rafluoroethylene-based local infusion devices were implanted bilaterally as femoral AV conduits in six dogs. The venous anastomoses were the sites of continuous delivery of rFGF2-SAP (2.7 micrograms.kg-1.d-1) to one side and vehicle (4.6 microL.kg-1.d-1) as control to the contralateral side for 14 days. All animals survived, and all grafts were patent. Liver enzyme levels and histological analyses of liver, kidneys, and brain were normal, indicating the absence of systemic toxicity. Morphometric measurements and measurements of cell proliferation by bromodeoxyuridine index analysis were performed at both arterial and venous anastomoses. There were no significant differences between the treated grafts and the control grafts in intimal hyperplasia and intimal cell proliferation at the arterial anastomoses. In contrast, rFGF2-SAP reduced intimal thickness by 32%, intimal area by 40%, and cell proliferation index by 33% at the treated venous anastomoses compared with the control venous anastomoses (P < .05).

CONCLUSIONS

These data demonstrate that local infusion of rFGF2-SAP significantly reduces venous anastomotic intimal hyperplasia and cell proliferation without systemic toxicity. This study suggests a new strategy for reducing intimal hyperplasia by the selective killing of proliferating smooth muscle cells with a potent chimeric mitotoxin through a novel local infusion device.

Intraventricular infusion of basic fibroblast growth factor (bFGF) in the MPTP-treated common marmoset

Basic fibroblast growth factor (bFGF) prevents damage to the nigrostriatal system in rodents. We now report the effects of bFGF administered by intraventricular infusion to adult common marmosets (Callithrix jacchus) previously rendered parkinsonian by the administration of 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Infusion commenced 10 weeks after MPTP treatment and the animals received bFGF in low (1.8 micrograms/l), medium (18 micrograms/l), or high (180 micrograms/l) doses over a 28-day period. At weekly intervals, automated activity measurements, behavioral disability scoring, and videotape analyses were made. There was no improvement in the motor deficits exhibited by MPTP-treated common marmosets receiving bFGF infusion compared to vehicle-treated controls. Three of five high dose animals showed neurological impairment prior to the end of the study. No significant differences were found between control and bFGF-infused MPTP-treated common marmosets with respect to nigral tyrosine hydroxylase immunoreactive cell counts and striatal [3H]mazindol binding. All high dose animals showed hydrocephalus which was also observed in four other animals receiving bFGF. Histological examination revealed proliferation of the choroid plexus and ependyma which was most marked in the high dose animals. Adverse effects, in the form of hydrocephalus and neurological deterioration, were presumably secondary to an ependymal and choroid plexus reaction induced by bFGF.

Investigation of calmodulin and basic fibroblast growth factor (bFGF) in idiopathic myelofibrosis: evidence for a role of extracellular calmodulin in fibroblast proliferation

The urinary concentration of calmodulin and basic fibroblast growth factor (bFGF) was determined in a total of 53 patients with various chronic myeloproliferative disorders (CMPD), including 22 patients with idiopathic myelofibrosis (IMF). Calmodulin excretion was significantly elevated in IMF (0.29 +/- 0.04 microgram/mmol creatinine) (P < 0.001), when compared to polycythaemia vera (PV) (0.14 +/- 0.02), essential thrombocythaemia (ET) (0.13 +/- 0.04), chronic myeloid leukaemia (CML) (0.16 +/- 0.02), unclassified myeloproliferative disorders (UMPD) (0.11 +/- 0.02) and age-matched controls (0.1 +/- 0.02) (P < 0.001). In contrast, bFGF was slightly elevated in all CMPD conditions when compared to age-matched controls. A neutralizing antibody to calmodulin was demonstrated to significantly influence the in vitro proliferation of normal human fibroblasts, an effect dependent on both cell density and the presence of fetal calf serum (FCS). Essentially, the antibody reduced FCS-induced proliferation of low-density fibroblasts but had little or no inhibitory effect on high-density fibroblasts in the absence of FCS. In addition, extracellular calmodulin was shown not to interact with known fibroblast mitogens, namely, IFG-1, EGF, bDGF and PDGF. We conclude that extracellular calmodulin should be considered, in addition to PDGF, TFG-beta and EGF, as a potential mitogen involved in the stromal reaction of idiopathic myelofibrosis.

The safety and effect of topically applied recombinant basic fibroblast growth factor on the healing of chronic pressure sores

The first randomized, blinded, placebo-controlled human trials of recombinant basic fibroblast growth factor (bFGF) for pressure sore treatment were performed. Three different concentrations of bFGF in five dosing schedules were tested for safety using hematology, serum chemistries, urinalysis, absorption, antibody formation, and signs of toxicity. Efficacy was evaluated by wound volumes, histology, and photography. No toxicity, significant serum absorption, or antibody formation occurred. In six of eight subgroups, there was a trend toward efficacy with bFGF treatment. When all subgroups were combined, comparison of the slopes of the regression curves of volume decrease over initial pressure sore volume demonstrated a greater healing effect for the bFGF-treated patients (p < 0.05). Histologically, bFGF-treated wound sections demonstrated increased fibroblasts and capillaries. More patients treated with bFGF achieved > 70% wound closure (p < 0.05). Blinded observers were able to distinguish differences in visual wound improvement between bFGF and placebo groups. These data suggest that bFGF may be effective in the treatment of chronic wounds.

Antitumor activity of basic fibroblast growth factor-saporin mitotoxin in vitro and in vivo

Many cancer cell lines express basic fibroblast growth factor (FGF) receptors, making them potential targets for the delivery of FGF-based cytotoxic compounds. To this end, we have investigated the antitumor activity of a novel mitotoxin, Fibroblast Growth Factor-saporin (FGF-SAP), a conjugate of FGF and the ribosome-inactivating protein, saporin. In vitro, FGF-SAP is cytotoxic for human melanoma, teratocarcinoma, and neuroblastoma cells expressing FGF-receptors. Mice treated with FGF-SAP i.v., on a variety of schedules, showed dramatic tumor growth inhibition with minimal toxicity. Thus, FGF-SAP appears to be a well-tolerated and potent antitumor agent. The potential of FGF-targeted cytotoxicity is discussed.