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L Giardino

Publications and source records attributed to L Giardino.

At least 19 recordsLinked to original sources
PubMed2006

Endogenous stem and precursor cells for demyelinating diseases: an alternative for transplantation?

Remyelination can be very effective in human. However, this process ultimately fails in multiple sclerosis (MS). In this paper, we discuss the possibility of stimulating endogenous oligodendrocyte precursors to participate in remyelination in experimental models (rat and primate Callithrix jacchus) of MS through thyroid hormone (TH) administration. TH is in fact known to be a key signal in brain development, oligodendrocyte development and myelin protein gene expression regulation.

Animals↗
PubMed2005

Role of c-Fos protein on glutamate toxicity in primary neural hippocampal cells.

The hippocampus is extremely sensitive to microenvironmental signals and toxic events, including massive glutamate release. Despite the extensive literature related to the cascade of molecular events triggered in postsynaptic neurons, the distinction between proapoptotic and survival pathways is still being discussed. In this study, we have investigated the role of c-Fos in glutamate-induced toxicity in primary cultures of hippocampal neurons by using antisense oligonucleotide (ASO) technology. Exposure of cells (5 days in vitro; DIV) to glutamate 0.5 mM for 24 hr caused massive nuclear alteration. An increase in the number of caspase-3-positive cells was also observed 24 hr after glutamate treatment. The expression of c-fos and c-jun immediate-early genes was increased 30 min after glutamate exposure. The study of c-Fos and c-Jun protein expression revealed an increase in the number of cells positive for both antibodies. To investigate whether the expression of c-Fos protein after glutamate treatment was related to cell death activation or cell survival pathways, cells were exposed to 5 microM of c-fos ASO at 4 DIV, 24 hr before glutamate treatment. The presence of the ASO in the medium significantly decreased the number of altered nuclei, and this was associated with a significant reduction in the number of c-Fos-positive cells after glutamate treatment. Exposure of cells to the c-fos ASO under the conditions described above decreased caspase-3 immunostaining induced by glutamate. These results suggest that the synthesis of c-Fos protein after glutamate exposure favors cell death pathway activation in which caspase-3 is also involved.

Analysis of Variance↗
PubMed2005

Behavioral and neurochemical studies on brain aging in galanin overexpressing mice.

To study possible involvement of galanin in brain aging quality, we have investigated behavioral, neurochemical and morphological parameters in aged mice overexpressing galanin under the platelet-derived growth factor B promoter (GalOE mice) compared to wild-type littermates (WT mice). The behavioral analysis in the forced swim test showed that old GalOE animals spent more time in immobility compared to WT. In the activity cage test, galanin overexpression counteracted the age-induced decrease in exploratory behavior. The neurochemical analysis showed a 30% decrease in noradrenaline overflow in the cerebral cortex of WT old mice that was not present in age-matched GalOE mice. Our results indicate that overexpression of galanin can influence several behavioral and neurochemical parameters in old mice.

Aging↗
PubMed2004

p75(NTR)-immunoreactivity in the subventricular zone of adult male rats: expression by cycling cells.

While the study of in vitro regulation of neural stem cell lineage from both embryonic and adult neurospheres is greatly advanced, much less is known about factors acting in situ for neural stem cell lineage in adult brain. We reported that neurotrophin low affinity receptor p75(NTR) is present in the subventricular zone (SVZ) in adult male rats. We then characterized co-distribution of markers associated with precursor cells (nestin and PSA-NCAM) with growth factor receptors (p75(NTR), trkA, EGFr) and proliferation-associated antigens (Ki67 and BrDU-uptake) in adult male rat by immunocytochemistry and confocal laser scan microscopy. Distribution of p75(NTR)-immunoreactivity (IR) was investigated using different mono- and polyclonal antisera. p75(NTR-) is not co-distributed with glial fibrillary acid protein. It was found to be co-distributed with a small number of nestin-IR cells, whereas no coexistence with PSA-NCAM-IR was observed. Conversely, p75(NTR)-IR was present in numerous dividing cells (Ki-67-positive) and co-distributed with EGFr. In order to verify the possible association between p75(NTR) and cell death, we investigated co-distribution of p75(NTR)-IR with nuclear condensation images as visualized by Hoechst 33258 staining. While few images indicating nuclear condensation were observed in the SVZ, no coexistence with p75(NTR) was found. TrkA- and trkB-IR was not found in the SVZ. We also investigated p75(NTR) immunostaining on post-natal day 1 and day 16, because of the dramatic reduction of proliferating cells in SVZ over this time-interval. p75(NTR)-IR was not increased in the early post-natal phase. Thus, p75(NTR) seems to be associated with cell cycle regulation in SVZ in adult rat brain.

Animals↗
PubMed2004

Spinal motoneurone distress during experimental allergic encephalomyelitis.

The main pathophysiological feature characterizing multiple sclerosis (MS) is demyelination. However, the possibility of neural damage has recently been proposed as a mechanism in chronic disease. Experimental allergic encephalomyelitis (EAE) is the most widely used experimental model for MS. We investigated occurrences of microglial activation and astrocytosis in the spinal cord, choline acetyl-transferase (ChAT) and calcitonin gene-related peptide (CGRP) mRNA regulation in spinal motoneurones during EAE. EAE was induced in female Lewis rats by injecting guinea pig spinal cord tissue in complete Freund's adjuvant (CFA) to which heat-inactivated Mycobacterium had been added. Rats injected with CFA and uninjected rats were used as controls. ChAT and CGRP mRNAs were studied by in situ hybridization in the lumbar spinal cord and a computerized grain counting procedure was used for quantification. No differences in ChAT mRNA level were found between control and CFA-injected rats. ChAT mRNA level was strongly reduced in EAE 14 days after immunization and then recovered (29 days after immunization). CGRP mRNA increased 14 days after immunization, and then recovered to control level. Extensive long-lasting gliosis developed in the spinal cord and around motoneurones and a transient expression of p75LNGFR in motoneurones was also found. These data suggest that during EAE, gliosis induces distress in spinal cord neurones involving the synthesis enzyme for the main transmitter.

Animals↗
PubMed2004

Thyroid hormone participates in the regulation of neural stem cells and oligodendrocyte precursor cells in the central nervous system of adult rat.

Oligodendrocyte development and myelination are under thyroid hormone control. In this study we analysed the effects of chronic manipulation of thyroid status on the expression of a wide spectrum of oligodendrocyte precursor cells (OPCs) markers and myelin basic protein (MBP) in the subventricular zone (SVZ), olfactory bulb and optic nerve, and on neural stem cell (NSC) lineage in adult rats. Hypo- and hyperthyroidism were induced in male rats, by propyl-thio-uracil (PTU) and L-thyroxin (T4) treatment, respectively. Hypothyroidism increased and hyperthyroidism downregulated proliferation in the SVZ and olfactory bulb (Ki67 immunohistochemistry and Western blotting, bromodeoxyuridine uptake). Platelet-derived growth factor receptor alpha (PDGFalpha-R) and MBP mRNA levels decreased in the optic nerve of hypothyroid rats; the same also occurred at the level of MBP protein. Hyperthyroidism slightly upregulates selected markers such as NG2 in the olfactory bulb. The lineage of cells derived from primary cultures of NSC prepared from the forebrain of adult hypo- and hyperthyroid also differs from those derived from control animals. Although no difference of in vitro proliferation of NSCs was observed in the presence of epidermal growth factor, maturation of oligodendrocytes (defined by process number and length) was enhanced in hyperthyroidism, suggesting a more mature state than in control animals. This difference was even greater when compared with the hypothyroid group, the morphology of which suggested a delay in differentiation. These results indicate that thyroid hormone affects NSC and OPC proliferation and maturation also in adulthood.

Animals↗
PubMed2004

Very low level laser therapy attenuates edema and pain in experimental models.

In this study, we tested a new square wave microprocessor-controlled red laser with an extremely low peak power output (<3 mW; very low level laser therapy [vLLLT]) in experimental pain in the rat. Acute inflammation was induced by intraplantar injection of carrageenan, chronic inflammation was induced by complete Freund's adjuvant (CFA) and neuropathic pain was produced by sciatic nerve chronic constriction injury (CCI). In our study vLLLT was effective in reducing edema and hyperalgesia in acute and chronic inflammation if administered at the points usually selected for acupuncture. Moreover, spontaneous pain and thermal hyperalgesia were reduced in CCI rats treated with vLLLT In conclusion, vLLLT reduced edema and induced analgesia in experimental plantar pain in rats. We interpret this to mean that enkephalin mRNA level was strongly upregulated in the external layers of the dorsal horn of the spinal cord in CFA and CCI animals, and that vLLLT further increased the mRNA level in single neurons.

Animals↗
PubMed2002

Neurotensin enhances glutamate excitotoxicity in mesencephalic neurons in primary culture.

The tridecapeptide neurotensin has been demonstrated to increase glutamate release in discrete rat brain regions, leading to the hypothesis of a possible involvement of the peptide in neurodegenerative pathologies. The role of neurotensin in modulating glutamate excitotoxicity and the possible neuroprotective action of the neurotensin receptor antagonist SR48692 were investigated in primary cultures of mesencephalic neurons by measuring [(3)H]dopamine uptake and tyrosine hydroxylase immunocytochemistry 24 hr after glutamate treatment. The exposure to glutamate (30 and 100 microM, 10 min) decreased [(3)H]dopamine uptake into mesencephalic neurons. Neurotensin (10 and 100 nM), added before glutamate (30 microM) exposure, significantly enhanced the glutamate-induced reduction of [(3)H]dopamine uptake. In addition, the peptide (10 nM) also significantly enhanced the effect of 100 microM glutamate. The effects of neurotensin were counteracted by the neurotensin receptor antagonist SR48692 (100 nM) and by the protein kinase C inhibitor calphostin C. The exposure to 100 microM, but not 30 microM, glutamate significantly reduced the number of tyrosine hydroxylase-immunoreactive cells, and neurotensin (10 nM) significantly enhanced this effect. SR48692 (100 nM) prevented the neurotensin-induced action. These findings support the view of a possible pathophysiological role of neurotensin in mesencephalic dopamine neuronal function. Furthermore, selective neurotensin antagonists in combination with conventional drug treatments could provide a novel therapeutic approach for the treatment of neurodegenerative disorders, such as Parkinson's disease.

Animals↗
PubMed2002

Neuroprotection and aging of the cholinergic system: a role for the ergoline derivative nicergoline (Sermion).

The aging brain is characterized by selective neurochemical changes involving several neural populations. A deficit in the cholinergic system of the basal forebrain is thought to contribute to the development of cognitive symptoms of dementia. Attempts to prevent age-associated cholinergic vulnerability and deterioration therefore represent a crucial point for pharmacotherapy in the elderly. In this paper we provide evidence for the protective effect of nicergoline (Sermion) on the degeneration of cholinergic neurons induced by nerve growth factor deprivation. Nerve growth factor deprivation was induced by colchicine administration in rats 13 and 18 months old. Colchicine induces a rapid and substantial down-regulation of choline acetyltransferase messenger RNA level in the basal forebrain in untreated adult, middle-aged and old rats. Colchicine failed to cause these effects in old rats treated for 120 days with nicergoline 10 mg/kg/day, orally. Moreover, a concomitant increase of both nerve growth factor and brain-derived neurotrophic factor content was measured in the basal forebrain of old, nicergoline-treated rats. Additionally, the level of messenger RNA for the brain isoform of nitric oxide synthase in neurons of the basal forebrain was also increased in these animals. Based on the present findings, nicergoline proved to be an effective drug for preventing neuronal vulnerability due to experimentally induced nerve growth factor deprivation.

Aging↗
PubMed2001

Nerve growth factor control of neuronal expression of angiogenetic and vasoactive factors.

In postnatal tissues, angiogenesis occurs in nontumoral conditions on appropriate stimuli. In the nervous tissue, hypoxia, neural graft, increased neural function, and synaptic activity are associated with neoangiogenesis. We have investigated the occurrence of neoangiogenesis in the superior cervical ganglia (scg) of newborn rats treated for 8--21 days with 6-hydroxy-dopamine (6-OHDA), nerve growth factor (NGF), or 6-OHDA + NGF. The two latter treatments induced a significant increase in scg size. However, the increase after combined treatment far exceeded that of NGF alone. Similarly, histological and histochemical analysis revealed neuronal hypertrophy and endothelial cell hyperplasia associated with stromal hypertrophy (as described by laminin immunostaining) and increased vascular bed (as revealed by platelet/endothelial cell adhesion molecule-1 immunostaining) in 6-OHDA + NGF-treated pups. NGF, either alone or associated with 6-OHDA, also induced a significant up-regulation of NADPH diaphorase, neuronal nitric oxide synthase, and vascular endothelial growth factor expression in scg neurons. The present investigation suggests that the increase of scg size induced by NGF and 6-OHDA + NGF is associated with neoangiogenesis, and that the induction of vasoactive and angiogenic factors in neurons represents a further and previously undisclosed effect of NGF.

Adrenergic Agents↗
PubMed2000

In vivo regulation of precursor cells in the subventricular zone of adult rat brain by thyroid hormone and retinoids.

The mature central nervous system contains precursor cells in the subventricular zone of the lateral ventricle. In this study we examined the possibility to affect fate of precursor cells through exogenous manipulations. The results indicate that administration of thyroid hormone and retinoic acid increases the expression of Ki67, a nuclear antigen associated with cell proliferation, and of nestin, a marker protein for precursor cells in the subventricular zone of adult male rats. Moreover, retinoic acid increases polysialated-neural cell adhesion molecules (PSA-NCAM)-immunoreactivity. These data suggest that nuclear receptor ligands are potential candidates for fate determination of precursor cells in the subventricular zone also in the adult brain.

Animals↗
PubMed2000

Exogenous administration of L-arginine protects cholinergic neurons from colchicine neurotoxicity.

The effect of L-arginine administration on susceptibility/resistance of NO-producing neurons was investigated in non-ischemic neurodegenerative conditions. ChAT mRNA level was measured by in situ hybridization in the basal forebrain after i.c.v. colchicine administration. Colchicine induced down-regulation of ChAT mRNA level followed by degeneration of cholinergic neurons. L-Arginine treatment increased ChAT mRNA level and prevented/delayed ChAT mRNA decrease by colchicine. These data suggest that L-arginine treatment may protect cholinergic neurons from colchicine-induced degeneration.

Animals↗
PubMed2000

Further evidence for a role of nitric oxide in experimental allergic encephalomyelitis: aminoguanidine treatment modifies its clinical evolution.

The role of nitric oxide (NO) in inflammatory/demyelinating diseases is undergoing extensive investigation as a potential target for therapeutic intervention. However, interference with NO production has resulted in contrasting effects on the development of experimental allergic encephalomyelitis (EAE), the most widely used experimental model for multiple sclerosis (MS). Purpose of this paper was both the analysis of the individual clinical evolution of EAE induced in Lewis female rats by active immunisation and the evaluation of the effect of treatment with aminoguanidine, a selective inhibitor for the inducible isoform of nitric oxide synthase (iNOS). In our experimental model, relapse occurred in 66% of animals. Aminoguanidine treatment, started 3 days before immunisation, guaranteed a complete recovery from the acute phase and a delayed, milder relapse. Moreover, 79 days after immunisation inflammatory cellular infiltrates in the spinal cord were reduced. These data further support the involvement of NO in EAE evolution.

Acute Disease↗
PubMed1999

Expression analysis and protein localization of the human HPC-1/syntaxin 1A, a gene deleted in Williams syndrome.

The HPC-1/syntaxin 1A (STX1A) gene maps to the Williams syndrome (WS) commonly deleted region on chromosome 7q11.23 and encodes a protein implicated in the docking of synaptic vesicles with the presynaptic plasma membrane. To assess the potential role of STX1A in the WS phenotype, we carried out expression studies at the RNA and protein levels, in fetal and adult human tissues. RNA in situ hybridization on human embryo sections showed strong STX1A expression in spinal cord and ganglia. However, in adulthood, this gene was preferentially expressed in brain, as shown by Northern blot and RT-PCR experiments. Marked expression levels were observed in cerebellum and cerebral cortex. The STX1A protein was prevalently distributed in the molecular layer of the cerebellar cortex. A qualitative and quantitative analysis using a specific anti-STX1A antibody did not disclose any significant difference among frontal, temporal, and occipital poles of the human adult cortex in the two hemispheres. This is the first study focused on STX1A expression in humans. Our results indicate that this gene is strongly expressed in cerebral areas involved in cognitive process, supporting a likely role in the neurological symptoms of WS.

Antigens, Surface↗
PubMed1999

Regulation of CCK mRNA expression in the rat brain by stress and treatment with sertraline, a selective serotonin re-uptake inhibitor.

In this paper, we have investigated the regulation of CCK mRNA expression in the brain after restraint stress with and without long-term treatment with the selective serotonin reuptake inhibitor sertraline. Stress alone increases CCK mRNA levels in the hippocampus, whereas no changes were found in the cerebral cortex, amygdaloid complex and thalamus. CCK mRNA expression decreases in the hippocampus, increases in the thalamus and was not modified in the cerebral cortex and amygdaloid complex after sertraline alone. CCK mRNA content was unchanged in all investigated areas after stress plus sertraline compared to control rats.

Animals↗
PubMed1998

Proliferation and phenotype regulation in the subventricular zone during experimental allergic encephalomyelitis: in vivo evidence of a role for nerve growth factor.

Proliferating cells in the subventricular zone (SVZ) of adult rat brain could provide a source of cells for repair attempts during degenerative diseases. However, very few reports dealt with the spontaneous regulation of this cell population during experimental conditions. In this paper, we describe an increase in the proliferation activity in the SVZ during experimental allergic encephalomyelitis, a demyelinating disease widely used as an experimental model for human multiple sclerosis. Moreover, p75(LNGFR)-immunoreactive elements in the SVZ were larger in experimental allergic encephalomyelitis compared with control groups, and they also showed multiple and branched elongations. Finally, a selective uptake of 125I-nerve growth factor was observed in the SVZ in neonatal rats, and positive elements migrated in the corpus callosum within a few days. These data indicate that cell populations in the SVZ are regulated during inflammatory conditions and degenerative diseases involving oligodendrocytes and neurotrophins, including nerve growth factor, could participate in these phenomena.

Animals↗