Fibroblast growth factor-8 protects cultured rat hippocampal neurons from oxidative insult

Cerebellar Morphology and Behavioral Profiles in Mice Lacking Heparan Sulfate Ndst Gene Function

Disruption of the Heparan sulfate (HS)-biosynthetic gene N-acetylglucosamine N-Deacetylase/N-sulfotransferase 1 (Ndst1) during nervous system development causes malformations that are composites of those caused by mutations of multiple HS binding growth factors and morphogens. However, the role of Ndst function in adult brain physiology is less explored. Therefore, we generated mice bearing a Purkinje-cell-specific deletion in Ndst1 gene function by using Cre/loxP technology under the control of the Purkinje cell protein 2 (Pcp2/L7) promotor, which results in HS undersulfation. We observed that mutant mice did not show overt changes in the density or organization of Purkinje cells in the adult cerebellum, and behavioral tests also demonstrated normal cerebellar function. This suggested that postnatal Purkinje cell development and homeostasis are independent of Ndst1 function, or that impaired HS sulfation upon deletion of Ndst1 function may be compensated for by other Purkinje cell-expressed Ndst isoforms. To test the latter possibility, we additionally deleted the second Purkinje-cell expressed Ndst family member, Ndst2. This selectively abolished reproductive capacity of compound mutant female, but not male, mice, suggesting that ovulation, gestation, or female reproductive behavior specifically depends on Ndst-dependent HS sulfation in cells types that express Cre under Pcp2/L7 promotor control.

Effect of induced hypoglycemia on inflammation and oxidative stress in type 2 diabetes and control subjects

Intensive diabetes control has been associated with increased mortality in type 2 diabetes (T2DM); this has been suggested to be due to increased hypoglycemia. We measured hypoglycemia-induced changes in endothelial parameters, oxidative stress markers and inflammation at baseline and after a 24-hour period in type 2 diabetic (T2DM) subjects versus age-matched controls. Case-control study: 10 T2DM and 8 control subjects. Blood glucose was reduced from 5 (90 mg/dl) to hypoglycemic levels of 2.8 mmol/L (50 mg/dl) for 1 hour by incremental hyperinsulinemic clamps using baseline and 24 hour samples. Measures of endothelial parameters, oxidative stress and inflammation at baseline and at 24-hours post hypoglycemia were performed: proteomic (Somalogic) analysis for inflammatory markers complemented by C-reactive protein (hsCRP) measurement, and proteomic markers and urinary isoprostanes for oxidative measures, together with endothelial function. Between baseline and 24 -hours after hypoglycemia, 15 of 140 inflammatory proteins differed in T2DM whilst only 1 of 140 differed in controls; all returned to baseline at 24-hours. However, elevated hsCRP levels were seen at 24-hours in T2DM (2.4 mg/L (1.2-5.4) vs. 3.9 mg/L (1.8-6.1), Baseline vs 24-hours, P < 0.05). In patients with T2DM, between baseline and 24-hour after hypoglycemia, only one of 15 oxidative stress proteins differed and this was not seen in controls. An increase (P = 0.016) from baseline (73.4 ng/mL) to 24 hours after hypoglycemia (91.7 ng/mL) was seen for urinary isoprostanes. Hypoglycemia resulted in inflammatory and oxidative stress markers being elevated in T2DM subjects but not controls 24-hours after the event.

Macrophage migration inhibitory factor (MIF) modulates trophic signaling through interaction with serine protease HTRA1

Macrophage migration inhibitory factor (MIF), a small conserved protein, is abundant in the immune- and central nervous system (CNS). MIF has several receptors and binding partners that can modulate its action on a cellular level. It is upregulated in neurodegenerative diseases and cancer although its function is far from clear. Here, we report the finding of a new binding partner to MIF, the serine protease HTRA1. This enzyme cleaves several growth factors, extracellular matrix molecules and is implicated in some of the same diseases as MIF. We show that the function of the binding between MIF and HTRA1 is to inhibit the proteolytic activity of HTRA1, modulating the availability of molecules that can change cell growth and differentiation. MIF is therefore the first endogenous inhibitor ever found for HTRA1. It was found that both molecules were present in astrocytes and that the functional binding has the ability to modulate astrocytic activities important in development and disease of the CNS.

Fibroblast growth factors in the management of spinal cord injury

Spinal cord injury (SCI) possesses a significant health and economic burden worldwide. Traumatic SCI is a devastating condition that evolves through two successive stages. Throughout each of these stages, disturbances in ionic homeostasis, local oedema, ischaemia, focal haemorrhage, free radicals stress and inflammatory response were observed. Although there are no fully restorative cures available for SCI patients, various molecular, cellular and rehabilitative therapies, such as limiting local inflammation, preventing secondary cell death and enhancing the plasticity of local circuits in the spinal cord, were described. Current preclinical studies have showed that fibroblast growth factors (FGFs) alone or combination therapies utilizing cell transplantation and biomaterial scaffolds are proven effective for treating SCI in animal models. More importantly, some studies further demonstrated a paucity of clinical transfer usage to promote functional recovery of numerous patients with SCI. In this review, we focus on the therapeutic capacity and pitfalls of the FGF family and its clinical application for treating SCI, including the signalling component of the FGF pathway and the role in the central nervous system, the pathophysiology of SCI and the targets for FGF treatment. We also discuss the challenges and potential for the clinical translation of FGF-based approaches into treatments for SCI.

Potential role of growth factors in the management of spinal cord injury

OBJECTIVE

To review central nervous system growth factors and their therapeutic potential and clinical translation into spinal cord injury (SCI), as well as the challenges that have been encountered during clinical development.

METHODS

A systemic review of the available current and historical literature regarding central nervous system growth factors and clinical trials regarding their use in spinal cord injury was conducted.

RESULTS

The effectiveness of administering growth factors as a potential therapeutic strategy for SCI has been tested with the use of brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, neurotrophin 3, and neurotrophin-4/5. Delivery of growth factors to injured SC has been tested by numerous methods. Unfortunately, most of clinical trials at this time are uncontrolled and have questionable results because of lack of efficacy and/or unacceptable side effects.

CONCLUSIONS

There is promise in the use of specific growth factors therapeutically for SCI. However, more studies involving neuronal regeneration and functional recovery are needed, as well the development of delivery methods that allow sufficient quantity of growth factors while restricting their distribution to target sites.

Heterozygous mutations in the FGF8, SHH and nodal/transforming growth factor beta pathways do not confer increased dopaminergic neuron vulnerability--a zebrafish study

Fibroblast growth factor 8 (FGF8), sonic hedgehog (SHH) and nodal signalling pathways play key roles in both development and survival of dopaminergic neurons. Both heterozygous mutations in autosomal recessively inherited Parkinson's disease (PD) genes such as parkin or PINK1 and exposure to exogenous toxins are thought to contribute to the pathogenesis of PD. The aim of our study was to investigate whether heterozygote mutations in fgf8, shh or oep lead to a reduced number of ascending dopaminergic neurons in zebrafish (Danio rerio) or confer increased susceptibility to the PD neurotoxin 1-methyl-4-phenyl-pyridinium (MPP⁺). At 3 days post fertilization, heterozygous mutations in fgf8, shh or oep did not affect the number of ascending dopaminergic neurons, nor did heterozygous mutations in fgf8, shh or oep result in increased susceptibility to MPP⁺. Further work is needed to determine whether haploinsufficiency in other neurodevelopmental genes might confer increased susceptibility to PD-related pathomechanisms.

Klotho interferes with a novel FGF-signalling pathway and insulin/Igf-like signalling to improve longevity and stress resistance in Caenorhabditis elegans

Klotho exerts anti-aging properties in mammals in two different ways. While membrane-bound Klotho, which is primarily expressed in the kidney, acts as an obligate co-receptor of FGF23 to regulate phosphate homeostasis, secreted Klotho, resulting from the shedding of the KL1-KL2 ectodomain into the bloodstream, inhibits Insulin/IGF1 signalling. However, the underlying molecular mechanisms are not fully understood. Here, we investigated the biological role of Klotho inCaenorhabditis elegans.

Two redundant homologues of the klotho gene exist in C. elegans and encode predicted proteins homologous to the β glucosidase-like KL1 domain of mammalian Klotho. We have used a genetic approach to investigate the functional activity of Klotho in C. elegans. Here, we report that whereas Klotho requires EGL-15 (FGFR) and EGL-17 to promote longevity and oxidative stress resistance, it is not involved in the regulation of fluid homeostasis, controlled by LET-756. Besides revealing a new post-developmental role for EGL-17, our data suggest that the KL1 form of Klotho is involved in FGF23-independent FGF signalling. We also report a genetic interaction between Klotho and the DAF-2 (Ins/IGF1R)/DAF-16 (FOXO) pathway. While the regulation of longevity requires functional DAF-2/DAF-16 signalling, the control of oxidative stress resistance involves a DAF-2- independent, DAF-16-dependent pathway, suggesting that Klotho may target either DAF-2 or DAF-16, depending of environmental conditions. Thus, the predictive KL1 form of Klotho appears to crosstalk with both FGF and Insulin/IGF1/FOXO pathways to exert anti-aging properties in C. elegans.

Regulation of cell cycle and DNA repair in post-mitotic GABA neurons in psychotic disorders

Disturbances of cell cycle regulation and DNA repair in post-mitotic neurons have been implicated in degenerative and malignant diseases of the human brain. Recent work is now suggesting that abnormal regulation of these functions in GABA cells of the adult hippocampus may also play a role in two neuropsychiatric disorders. In schizophrenia and bipolar disorder, a network of genes involved in the regulation of GAD₆₇, a marker for the functional differentiation of GABA cells, show pronounced changes in expression and include kainate receptor subunits, TGFβ and Wnt signaling pathways, epigenetic factors and transcription factors. One of these genes, cyclin D2, is involved in the regulation of cell cycle and DNA repair and appears to be a pivotal element in linking GAD₆₇ expression with these functional clusters of genes. Dysfunction of post-mitotic GABAergic neurons in the adult hippocampus of patients with psychotic disorders is associated with changes in the expression of genes that are involved in the maintenance of functional and genomic integrity of GABA cells. The nature of these changes is quite different in schizophrenia and bipolar disorder, suggesting that a common cell phenotype (in this case, decreased GAD₆₇ expression) may involve two fundamentally different molecular endophenotypes and reflect unique susceptibility genes involved in the respective disorders. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'.

Fibroblast growth factors in schizophrenia

A large association study by O'Donovan et al recently suggested that genetic variation in fibroblast growth factor receptor (FGFR) 2 increases the risk for developing schizophrenia. Fibroblast growth factors (FGFs) are part of the family of glial growth factors; they control the growth and patterning of specific brain structures and regulate the maintenance and repair of neuronal tissues. In addition, a direct interaction was recently found between FGFRs and adenosine A(2A) receptors, leading to corticostriatal plasticity and antagonizing the signaling pathway of dopamine D(2) receptors. These findings make FGFs plausible candidate genes for schizophrenia. Here, we review the role of FGFs in schizophrenia and combine evidence from studies on variations in FGF genes, RNA expression, protein levels, and FGF administration, as well as the effects of medication and environmental risk factors for schizophrenia. These data suggest that changes in the FGF system contribute to schizophrenia and possibly to a wider range of psychiatric disorders. The role of FGFs in schizophrenia and related disorders needs to be studied in more detail.

Upregulation of neurotrophic factor-related gene expression in retina with experimental autoimmune uveoretinitis by intravitreal injection of tacrolimus (FK506)

AIM

The current study was designed to determine whether intravitreal injection of tacrolimus (FK506) modulates the gene expression of neurotrophic factor-related molecules in the retina from eyes with induced experimental autoimmune uveoretinitis (EAU) in rats.

METHODS

Rats were immunised with interphotoreceptor retinoid binding protein peptide (R14) and given intravitreal injection of tacrolimus on day 12 after immunisation. As control, immunised rats received intravitreal injection of vehicle. On day 15 after immunisation, changes in the genetic programme associated with neuroprotection and inflammatory responses in the retinas from both groups were determined by DNA microarray analyses and confirmed by real-time PCR analyses.

RESULTS

The gene expression of inflammatory responses was markedly reduced in tacrolimus-treated eyes. Genes for molecules associated with neuroprotection (oestrogen receptor, erythropoietin receptor, gamma-aminobutyric acid receptor, protein kinase C, glial cell line-derived neurotrophic factor receptor, fibroblast growth factor and neuropeptide Y receptor) were upregulated in the retinas from tacrolimus-treated eyes.

CONCLUSIONS

Intravitreal injection of tacrolimus modulated the genes related to neuroprotection in the retina during the ongoing process of EAU. This treatment may be useful for the neuroprotection of retina with severe uveitis as well as for immunosuppression in the uveitic eyes.

Regulation of the GABA cell phenotype in hippocampus of schizophrenics and bipolars

GABAergic dysfunction is present in the hippocampus in schizophrenia (SZ) and bipolar disorder (BD). The trisynaptic pathway was "deconstructed" into various layers of sectors CA3/2 and CA1 and gene expression profiling performed. Network association analysis was used to uncover genes that may be related to regulation of glutamate decarboxylase 67 (GAD(67)), a marker for this system that has been found by many studies to show decreased expression in SZs and BDs. The most striking change was a down-regulation of GAD(67) in the stratum oriens (SO) of CA2/3 in both groups; CA1 only showed changes in the SO of schizophrenics. The network generated for GAD(67) contained 25 genes involved in the regulation of kainate receptors, TGF-beta and Wnt signaling, as well as transcription factors involved in cell growth and differentiation. In SZs, IL-1beta, (GRIK2/3), TGF-beta2, TGF-betaR1, histone deacetylase 1 (HDAC1), death associated protein (DAXX), and cyclin D2 (CCND2) were all significantly up-regulated, whereas in BDs, PAX5, Runx2, LEF1, TLE1, and CCND2 were significantly down-regulated. In the SO of CA1 of BDs, where GAD67 showed no expression change, TGF-beta and Wnt signaling genes were all up-regulated, but other transcription factors showed no change in expression. In other layers/sectors, BDs showed no expression changes in these GAD(67) network genes. Overall, these results are consistent with the hypothesis that decreased expression of GAD(67) may be associated with an epigenetic mechanism in SZ. In BD, however, a suppression of transcription factors involved in cell differentiation may contribute to GABA dysfunction.

The fibroblast growth factor system and mood disorders

Recent evidence now suggests the involvement of the fibroblast growth factor (FGF) system in mood disorders. Specifically, several members of the FGF family have been shown to be dysregulated in individuals with major depression. In this review, we will introduce the FGF system in terms of structure and function during development, in adulthood, and in various regions and cell types. We will also review the FGF system as a mediator of neural plasticity. Furthermore, this review will summarize animal as well as human studies. The majority of animal studies have focused on stress, environmental enrichment, pharmacological manipulations, and the hippocampus. By contrast, human studies have focused on volumetric measurements, antidepressant literature, and, most recently, post-mortem microarray experiments. In summary, a reduced tone in the FGF system might alter brain development or remodeling and result in a predisposition or vulnerability to mood disorders, including major depression.

Actions of neurotrophic factors and their signaling pathways in neuronal survival and axonal regeneration

Adult axons in the mammalian central nervous system do not elicit spontaneous regeneration after injury, although many affected neurons have survived the neurotrauma. However, axonal regeneration does occur under certain conditions. These conditions include: (a) modification of regrowth environment, such as supply of peripheral nerve bridges and transplantation of Schwann cells or olfactory ensheathing glia to the injury site; (b) application of neurotrophic factors at the cell soma and axon tips; (c) blockade of growth-inhibitory molecules such as Nogo-A, myelin-associated glycoprotein, and oligodendrocyte-myelin glycoprotein; (d) prevention of chondroitin-sulfate-proteoglycans-related scar tissue formation at the injury site using chondroitinase ABC; and (e) elevation of intrinsic growth potential of injured neurons via increasing intracellular cyclic adenosine monophosphate level. A large body of evidence suggests that these conditions achieve enhanced neuronal survival and axonal regeneration through sometimes overlapping and sometimes distinct signal transduction mechanisms, depending on the targeted neuronal populations and intervention circumstances. This article reviews the available information on signal transduction pathways underlying neurotrophic-factor-mediated neuronal survival and neurite outgrowth/axonal regeneration. Better understanding of signaling transduction is important in helping us develop practical therapeutic approaches for encouraging neuronal survival and axonal regeneration after traumatic injury in clinical context.

Motoneuronal death during spinal cord development is mediated by oxidative stress

The involvement of reactive oxygen species (ROS) in neuronal death has been determined in culture, and in association with several neurodegenerative disorders. We examined whether ROS participate in the cell death observed during spinal cord development. We found that the general pattern of high ROS levels, gene expression for some antioxidant enzymes, and motoneuron death correlated positively along spinal cord development. ROS were reduced in spinal cords cultured in the presence of a synthetic superoxide dismutase and catalase mimetic, with a concomitant reduction in cell death and an increase in the number of motoneurons. The number of motoneurons was higher in spinal cords treated with the antioxidant than in those treated with caspase inhibitors. In general, the increase in motoneuron survival did not correlate with the reduction in cells undergoing DNA degradation in the motoneuronal region. These results suggest that ROS are signaling molecules controlling caspase-dependent and caspase-independent programmed motoneuron death, and support the hypothesis that this mechanism is abnormally turned on in some neurodegenerative disorders and aging.

Distinct efficacy of pre-differentiated versus intact fetal mesencephalon-derived human neural progenitor cells in alleviating rat model of Parkinson's disease

Neural progenitor cells have shown the effectiveness in the treatment of Parkinson's disease, but the therapeutic efficacy remains variable. One of important factors that determine the efficacy is the necessity of pre-differentiation of progenitor cells into dopaminergic neurons before transplantation. This study therefore investigated the therapeutic efficacy of mesencephalon-derived human neural progenitor cells with or without the pre-differentiation in alleviating a rat model of Parkinson's disease. We found that a combination of 50 ng/ml fibroblast growth factor 8, 10 ng/ml glial cell line-derived neurotrophic factor and 10 microM forskolin facilitated the differentiation of human fetal mesencephalic progenitor cells into dopaminergic neurons in vitro. More importantly, after transplanted into the striatum of parkinsonian rats, only pre-differentiated grafts resulted in an elevated production of dopamine in the transplanted site and the amelioration of behavioral impairments of the parkinsonian rats. Unlike pre-differentiated progenitors, grafted intact progenitors rarely differentiated into dopaminergic neurons in vivo and emigrated actively away from the transplanted site. These data demonstrates the importance of pre-differentiation of human progenitor cells before transplantation in enhancing therapeutic potency for Parkinson's disease.

Forskolin cooperating with growth factor on generation of dopaminergic neurons from human fetal mesencephalic neural progenitor cells

Forskolin was tested for its co-activating ability to enhance the function of fibroblast growth factor (FGF) 8 on dopaminergic (DAergic) differentiation from human fetal mesencephalic neural progenitor cells (NPCs). When NPCs were treated with FGF8 alone, the DAergic phenotype was expressed lightly. The addition of 10 microM forskolin increased the number of DAergic neurons, cooperating with 50 ng/ml FGF8. These cells produced neurotransmitter DA, which was measured by high-performance liquid chromatography. Reverse transcriptase-polymerase chain reaction analysis demonstrated that differentiated cells expressed DAergic development-relative genes tyrosine hydroxylase (TH), nuclear receptor-related factor 1 (Nurr1) and D2 receptor (D2R), indicating that matured DAergic neurons could be obtained under these present conditions. The results suggest that forskolin plus FGF8 may contribute to more efficient production of DAergic neurons from human-derived NPCs for therapy of neurodegenerative diseases.

Fibroblast growth factors and neuroprotection

Several members of the FGF family, in particular FGF2, are intimately involved in neuronal protection and repair after ischemic, metabolic or traumatic brain injury. Expression of Fgf2 mRNA and protein is strongly upregulated after neuronal damage, with glial cells as the predominant source. Given its survival-promoting effects on cultured neurons, exogenous FGF2 was tested in several animal models of stroke and excitotoxic damage, in which it consistently proved protective against neuronal loss. FGF2 affords neuroprotection by interfering with a number of signaling pathways, including expression and gating of NMDA receptors, maintenance of Ca2+ homeostasis and regulation of ROS detoxifying enzymes. FGF2 prevents apoptosis by strengthening anti-apoptotic pathways and promotes neurogenesis in adult hippocampus after injury. The protective action of FGF2 has been linked to its augmenting effect on the lesion-induced upregulation of activin A, a member of the TGF-beta superfamily. Despite the well-documented benefits of FGF2 in animal models of stroke, there is currently no clinical development in stroke, after a phase II/III trial with FGF2 in acute stroke patients was discontinued because of an unfavorable risk-to-benefit ratio. As the molecular targets of FGF2 are going to be unraveled over the next years, new therapeutic strategies will hopefully emerge that enable us to influence the various protective mechanisms of FGF2 in a more specific fashion.

Pre- and post-treatment with pirlindole and dehydropirlindole protects cultured brain cells against nitric oxide-induced death

We have previously shown that pirlindole and dehydropirlindole, two monoamine oxidase type-A inhibitors, protect cultured brain cells against iron-induced toxicity through a mechanism unrelated to monoamine oxidase type-A inhibition. The current study was performed to test whether the protective effect of pirlindole and dehydropirlindole could be extended to a nitric oxide (NO)-induced insult. A comparison with other monoamine oxidase inhibitors (brofaromine, moclobemide and deprenyl) and with trolox was made. In a first series of experiments, rat hippocampal or cortical cultured cells were exposed to a drug for 3 h, then 5 microM sodium nitroprusside, a NO donor, was added and the incubation was continued for 16 h. Cell survival assessment showed that pirlindole, dehydropirlindole and trolox significantly protected cultures against NO-induced toxicity in a concentration-dependent manner with respective EC(50)'s of 7, 3 and 17 microM. Similarly, pirlindole, dehydropirlindole or trolox, at a concentration of 50 microM, significantly decreased both intracellular peroxide production and lipoperoxidation. Other drugs were ineffective. In a post-hoc treatment protocol (3- or 6-h pre-incubation in the presence of sodium nitroprusside, then addition of one of the above mentioned compounds), only pirlindole and dehydropirlindole significantly improved cell survival in a concentration-dependent manner with respective EC(50)'s of 9 and 4 microM. The maximal protection in terms of cell survival was 90% and 78% after 3 and 6 h, respectively. They also reduced the production of both lipoperoxides and endoperoxides. Our results show that pirlindole and dehydropirlindole protect neurons against NO-induced toxicity at pharmacologically relevant concentrations. Moreover, their protective effect is still apparent when they are applied after the start of the insult. Therefore, our preclinical study suggests a new strategy that may be efficient to reduce NO-induced damage in the central nervous system.

Extensive neuronal localization and neurotrophic function of fibroblast growth factor 8 in the nervous system

Fibroblast growth factor (FGF) 8 has been well established to play a critical role in the early development of the central nervous system (CNS). We report here extensive neuronal localization and neurotrophic function of FGF8 in the nervous system. In sections of mouse embryos at E10.5, FGF8 was immunohistochemically found in neurons at the marginal zones of the CNS and in the dorsal root ganglia (DRG). Neuronal localization of FGF8 was marked at later embryonic stages and in adults, involving most of the central and peripheral neurons, including intermuscular enteric neurons, DRGs, and paraaortic sympathetic ganglia. Functionally, FGF8 promoted neurite outgrowth in human neuroblastoma SK-N-MC cells as well as in rat pheochromocytoma PC12 cells, suggesting that FGF8 acts as a neurotrophic factor. FGF8 also supported neuronal survival and differentiation in cultured human neural progenitor cells. In a cell growth assay, treatment with 50 ng/ml FGF8 on human cultured neuroblastoma SK-N-MC and IMR32 cells attenuated the growth of both. In accordance with these in vitro findings, the immunohistochemical analysis on human neurological diseases showed that FGF8 expression is evident in differentiating histological types of neuroblastoma and ganglioneuroblastoma, and that the levels of FGF8 immunoreactivity in the substantia nigra from Parkinson's disease are significantly lower than those in age-matched controls. Taken together, the present findings strongly suggest that FGF8 acts as a more generalized neurotrophic factor than previously reported.

Keratinocyte growth factor prevents ischemia-induced delayed neuronal death in the hippocampal CA1 field of the gerbil brain

Fibroblast growth factors (FGFs) are polypeptides with various biological activities in vivo and in vitro, and their receptors are expressed in the widespread and specific neuronal populations of the brain. In this study, we asked whether keratinocyte growth factor (KGF), one of the FGF superfamily, would express in the brain, and have neuroprotective against ischemic brain injury. In situ hybridization analysis revealed that intense silver grains for KGF mRNA are observed in the neuronal cells of the cerebral cortex, hippocampus and amygdala in gerbil brain. Continuous cerebroventricular infusion of KGF (20 microg) for a 7 day period to gerbils starting 2 days before temporary right carotid artery occlusion (20 min) resulted in a higher survival rate than seen in vehicle-treated ischemic animals. Subsequent histological examinations showed that KGF effectively prevented delayed neuronal death of the hippocampal CA1 region. In situ detection of DNA fragmentation (TUNEL staining) revealed that ischemic animals infused with KGF contained fewer TUNEL-positive neurons in the hippocampal CA1 field than those infused with vehicle alone at the forth and seventh day after ischemia. KGF-treated brain showed over-expression of KGF mRNA in the neuronal cells of the cerebral cortex, hippocampus only in the right hemisphere, which was the side of carotid artery occlusion, 8-10 h after ischemia. These findings suggest that KGF has a protective effect against ischemic hippocampal neuronal damage in vivo, which may provide a new therapeutic strategy in the survival and reconstruction of neurons in response to cerebral injury.