Diana Reimers

Peripheral nerve regeneration by bone marrow stromal cells

Abstract Adult bone marrow contains stem cells that have attracted interest through their possible use for cell therapy in neurological diseases. Bone marrow stromal cells (MSCs) were harvested from donor adult rats, cultured and pre-labeled with bromodeoxyuridine (BrdU) previously to be injected in the distal stump of transected sciatic nerve of the rats. Distal nerve stump of control rats received culture medium solution. MSCs-treated rats exhibit significant improvement on walking track test at days 18 and 33 compared to controls. Dual immunofluorescence labeling shows that BrdU reactive cells survive in the injected area of transected sciatic nerve at least 33 days after implantation, and almost 5% of BrdU cells express Schwann cell-like phenotype (S100 immunoreactivity). Because MSCs injected in a lesioned peripheral nerve can survive, migrate, differentiate in Schwann cells, and promote functional recovery, they may be an important source for cellular therapy in several neurological diseases.

Pericyte endothelial gap junctions in human cerebral capillaries.

SummaryHuman cerebral tissue has been ultrastructurally studied and gap junctions have been visualized between endothelial cells and pericytes that permit ion exchange. We propose that the functional interrelationship between endothelium and pericytes may play a role in the alteration of capillary diameter for the control of local cerebral blood flow.

Cellular Characterization of Epidermal Growth Factor-expanded Free-floating Neurospheres

Neural stem cells proliferate in liquid culture as cell clusters (neurospheres). This study was undertaken to characterize the epidermal growth factor (EGF)-expanded free-floating neurospheres derived from rat fetal striatum. We examined the ultrastructural and antigenic characteristics of these spheres. They consisted of two cell types, electron-dense and electron-lucent cells. Lucent cells were immunopositive to actin, vimentin, and nestin, whereas dense cells were immunopositive to actin, weakly positive to vimentin, and nestin-negative. Neurospheres contained healthy, apoptotic, and necrotic cells. Healthy cells were attached to each other by adherens junctions. They showed many pseudopodia and occasionally a single cilium. Sphere cells showed phagocytic capability because healthy cells phagocytosed the cell debris derived from dead cells in a particular process that involves the engulfment of dying cells by cell processes from healthy cells. Sphere cells showed a cytoplasmic and a nuclear pool of fibroblast growth factor (FGF) receptors. They expressed E- and N-cadherin, α- and β-catenin, EGF receptor, and a specific subset of FGF receptors. Because sphere cells expressed this factor in the absence of exogenous FGF-2, we propose that they are able to synthesize FGF-2.

Developmental expression of fibroblast growth factor (FGF) receptors in neural stem cell progeny. Modulation of neuronal and glial lineages by basic FGF treatment

Abstract Neural stem cells (NSCs) are self-renewable, multipotential cells capable of differentiating into the three major neural cell types, but the mechanisms which regulate their development are not fully understood. Both basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) promote the proliferation of NSCs. However, studies on the role of FGFs in the differentiation of EGF-expanded NSCs are still incomplete. We have studied the expression of distinct FGF receptors (FGFRs) in the progeny of EGFexpanded NSCs isolated from E15 rat striatum. In situ hybridization analysis and immunocytochemistry showed a developmentally related expression pattern and a cell lineage-specific distribution of these receptors. FGFR1 and FGFR2 were identified in many early precursors and in the oligodendrocyte lineage. The latter receptor was also present in a subpopulation of astrocytes. FGFR3 was detected in a restricted population of early precursors, in oligodendroglial progenitors, and in neurons and protoplasmic astrocytes of late-term cultures. Basic FGF treatment of the progeny of NSCs increased the proliferative rate of precursors and the number of oligodendrocytes generated, whereas the number of differentiating neurons was significantly reduced. Together these data provide evidence that FGFs modulate the development of EGF-expanded NSCs, and that this is at least partly determined by a cell lineage-specific expression of multiple FGFRs. [Neurol Res 2001; 23: 612-621]

Intrastriatal infusion of liver growth factor stimulates dopamine terminal sprouting and partially restores motor function in 6-hydroxydopamine-lesioned rats.

Liver growth factor (LGF) is a mitogen for liver cells that shows biological activity in extrahepatic sites and may be useful for neuroregenerative therapies. The aim of this work was to investigate the effects of the intrastriatal (IS) infusion of LGF in the 6-hydroxydopamine rat model of Parkinsons disease. Tyrosine hydroxylase-positive innervation was significantly increased in the dopamine-denervated striatum of rats receiving intrastriatal LGF infusions (160 ng/day/rat × 15 days) as compared with a vehicle-infused group. There was no evidence of dopaminergic neurogenesis in the striatum or substantia nigra in any experimental group at the times studied. However, in those animals undergoing IS-LGF infusion for 48 hr, we found a significant increase in both microglial proliferation and in the number of microglial cells that acquired the ameboid morphology. This is characteristic of activated microglia/macrophages that has been reported to play an important role in dopamine terminal sprouting. In summary, our study shows that IS infusion of LGF stimulates the outgrowth of tyrosine hydroxylase-positive terminals in the striatum of 6-hydroxydopamine-treated rats. As apomorphine-induced rotational behavior was also reduced in these animals, we propose LGF as a novel factor that, when delivered to the striatum, may be useful in the treatment of Parkinsons disease.

Mobilization of Neural Stem Cells and Generation of New Neurons in 6-OHDA–lesioned Rats by Intracerebroventricular Infusion of Liver Growth Factor

Neural stem cells with self-renewal and multilineage potential persist in the subventricular zone of the adult mammalian forebrain. These cells remain relatively quiescent but, under certain conditions, can be stimulated, giving rise to new neurons. Liver growth factor (LGF) is a mitogen for liver cells that shows biological activity in extrahepatic sites and is useful for neuroregenerative therapies. The aim of this study was to investigate the potential neurogenic activity of LGF in the 6-hydroxydopamine rat model of Parkinsons disease. Proliferation was significantly increased in the subventricular zone and denervated striatum of rats receiving ICV LGF infusions, and 25% of the proliferating cells were doublecortin-positive neurons. Doublecortin-positive cells with the morphology of migrating neuroblasts were also observed in the dorsal and ventral regions of the striatum of LGF-infused animals. Moreover, some newly generated cells were neuronal nuclei-positive mature neurons. LGF also stimulated microglia and induced astrogliosis, both phenomena associated with generation and migration of new neurons in the adult brain. In summary, our study shows that LGF stimulates neurogenesis when applied intraventricularly in 6-hydroxydopamine–lesioned rats. Considering that this factor also promotes neuronal migration into damaged tissue, we propose LGF as a novel factor useful for neuronal replacement in neurodegenerative diseases. (J Histochem Cytochem 57:491–502, 2009)

Ischemic Reperfusion Injury in Rabbit Spinal Cord: Protective Effect of Superoxide Dismutase on Neurological Recovery and Spinal Infarction

The potential role of superoxide dismutase (SOD), a specific superoxide anion radical scavenger, in treating spinal cord ischemia was investigated in rabbits subjected to aortic occlusion for 20 min. SOD treatment, targeted to the early reperfusion period, reduced both motor dysfunction and incidence of spinal infarcts at 7 days after ischemia. Present results suggest that oxygen-derived free radicals play a role in the pathogenesis of infarcts developing in the spinal cord after ischemia and reperfusion injuries.

Acidic fibroblast growth factor rescues gerbil hippocampal neurons from ischemic apoptotic death.

Neurotrophic factors have been shown to support the survival of injured neurons and promote their recovery. Here, we investigated whether acidic fibroblast growth factor (aFGF) could modify programmed cell death caused by transient forebrain ischemia in the gerbil. The data show that systemic administration of 2.6 microg aFGF after 5 min ischemia followed by 7 days of brain reperfusion significantly (p < 0.05) reduced the occurrence of apoptotic cell death in CA1 neurons. These data suggest that aFGF would contribute to brain protection after acute stroke.

Immunohistochemical localization of basic fibroblast growth factor in choroid plexus of the rat

In the present study, we report that an intense bFGF-immunoreactivity has been detected in the choroid plexus of the brain ventricles of adult rats. These results suggest that epithelial choroid plexus cells may be the source of the cerebrospinal fluid bFGF.

Inhibition of intra-tumoral angiogenesis and glioma growth by the fibroblast growth factor inhibitor 1,3,6-naphthalenetrisulfonate

1,3,6-naphthalenetrisulfonate (NTS) can inhibit the proliferation in vitro of cells of various origin including glioma. We have studied the effects of NTS on intra-tumoral angiogenesis and tumor growth in the rabbit cornea after implantation of C6 rat glioma cells. It was found that neovascularization and glioma growth were abolished by topical administration of NTS. This effect could be mediated by both induction of programmed cell death and inhibition of growth, in endothelium and in tumor cells, most likely as a consequence of the disruption of the autocrine and paracrine effects of FGF released from endothelial and tumor cells. The results suggest that NTS is a promising candidate to lead the development of new angiogenesis inhibitors for the treatment of cancer and other diseases whose progression is dependent upon the development of new blood vessels.