Biomedical subjects

Tiziana Amendola

Publications and source records attributed to Tiziana Amendola.

8 recordsLinked to original sources

PubMed2005

Fighting in the aged male mouse increases the expression of TrkA and TrkB in the subventricular zone and in the hippocampus.

In the present study, we investigate the effect of aggressive behavior and release of nerve growth factor (NGF) on brain progenitor cells. We found that the condition of subordination enhances the level of NGF in the subventricular zone and hippocampus whereas dominance elevates brain derived neurotrophic factor (BDNF). It was also found that mRNA-TrkA is over-expressed in the subventricular zone and hippocampus of dominant and subordinate mice, whereas mRNA-TrkB is increased in the subventricular zone of both dominants and subordinates and in the hippocampus of dominant mice. Fighting was also associated with increased presence of proliferating cells in the hippocampus stained with the nuclear marker bromodeoxyuridine (BrdU). Moreover, the brain of subordinate mice displayed tyrosine hydroxylase (TH) immunoreactivity in the wall of the periventricular region of the third ventricles and a marked neuropeptide Y (NPY) presence in the hippocampus co-expressed with BrdU. These results provide additional evidence that agonistic behavior in the aged mouse alters neurotrophin levels and increases brain progenitor cells number. The functional significance of these findings is discussed.

Aggression↗

PubMed2005

Effect of exogenous administration of nerve growth factor in the retina of rats with inherited retinitis pigmentosa.

NGF is implicated in retinal damage regression. To study whether this is a direct effect or an effect mediated by NGF on other endogenous biological mediators, we investigated the effect of exogenous administration of NGF in RCS rats affected by retinitis pigmentosa. We found that NGF administration exerts a rescue effect on photoreceptors in this animal model. NGF injection enhances brain-derived neurotrophic factor, beta-fibroblast growth factor, transforming growth factor-beta, vascular endothelial factor and neuropeptide-Y. This suggests that NGF has an effect on RCS rat retina, probably also through the stimulation of other biological mediators produced and released in the retina.

Animals↗

PubMed2003

Postnatal changes in nerve growth factor and brain derived neurotrophic factor levels in the retina, visual cortex, and geniculate nucleus in rats with retinitis pigmentosa.

Royal College of Surgeons (RCS) rats are a well established animal model of inherited retinitis pigmentosa (RP). Using RCS rats we examined the distribution of nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) in the visual cortex, geniculate nucleus and retina at three different postnatal ages. It was found that the retina of rats with RP expresses low amounts of NGF and BDNF in young and adult life. Altered levels of these factors were found in the visual cortex and in the geniculate nucleus. Our findings indicate that NGF and BDNF are differentially affected in the visual system of developing and adult RCS rats, suggesting that neurotrophins may be implicated in the pathogenesis of inherited RP.

Age Factors↗

PubMed2003

Correlation between neurotrophic factor expression and outcome of children with severe traumatic brain injury.

OBJECTIVES: We evaluated the neurotrophic factors [nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glia-derived neurotrophic factor (GDNF)] expression and their association with the severity and outcome of children with traumatic brain injury. DESIGN: Prospective observational clinical study. SETTING: Pediatric intensive care unit. PATIENTS: Fourteen children with severe head injury; 12 controls with obstructive hydrocephalus. MEASUREMENT: Cerebrospinal fluid (CSF) and plasma samples were collected 2 h (T1) and 24 h (T2) after head injury. Neurotrophic factor levels were measured using an immuno-enzymatic assay. MAIN RESULTS: In patients, neurotrophic factor mean levels were significantly different in both CSF and plasma, showing high levels of BDNF compared to NGF and GDNF. Considering T1 and T2 expression, in the CSF the level of NGF increased from 3.5+/-0.4 pg/ml to 48.2+/-11.7 pg/ml ( p<0.001); BDNF decreased from 4854.0+/-1303.7 pg/ml to 593.0+/-114.8 pg/ml ( p<0.001), while GDNF did not undergo significant variations. In plasma, no significant changes were observed. Regarding severity and outcome, BDNF levels showed a sharp peak after head injury, but the only significant association was between NGF expression in the CSF and a good outcome versus a poor outcome ( p=0.007). CONCLUSIONS: The variations in neurotrophic factor levels reflect an endogenous attempt at neuroprotection against biochemical and molecular changes after traumatic head injury. BDNF represents an early marker of brain injury, while NGF expression in the CSF was indicative of a good outcome and the role of this neurotrophin in the treatment of children with severe head injury may be hypothesized.

Adolescent↗

PubMed2003

EGF and NGF injected into the brain of old mice enhance BDNF and ChAT in proliferating subventricular zone.

The response of cells localized in the brain subventricular zone (SVZ) to growth factor stimulation has been largely described for development and adult life, whereas no information on their behavior during aging is available. To address the question of whether the cells in the SVZ of old mice respond to the intracerebroventricular administration of epidermal growth factor (EGF) and nerve growth factor (NGF), we studied the distribution of proliferating cells and the effects on ChAT and brain-derived neurotrophic factor (BDNF) synthesis in forebrain and SVZ. It was found that the conjoint administration of EGF + NGF produced a major increase in ChAT expression in both forebrain and SVZ. The ChAT mRNA levels and the number of ChAT positive cells localized in the ventricular border and in the parenchyma of SVZ area were also increased significantly in the mice receiving EGF + NGF. Enhanced numbers of SVZ cells expressing proliferative markers were also discovered in EGF + NGF treated mice and some of these cells expressed cholinergic markers, as demonstrated by double immunostaining. In addition, EGF and NGF treatments significantly upregulate BDNF protein and mRNA levels in this brain region. The present study demonstrates that cells localized in SVZ of aged mouse brain retain the capacity to respond to EGF and NGF and that after stimulation with these two growth factors, the synthesis of ChAT and BDNF also increases. The implication that cells of the SVZ remain a reservoir of cholinergic and BDNF-positive neurons in aged brain opens a new perspective for understanding the role of growth factors during neurodegenerative disorders associated with aging.

Acetylcholine↗

PubMed2003

Agonistic encounters in aged male mouse potentiate the expression of endogenous brain NGF and BDNF: possible implication for brain progenitor cells' activation.

The condition of dominance or submission following agonistic encounters in the adult male mouse is known to differentially affect brain nerve growth factor, a neurotrophin playing a role in brain remodeling, in the fine tuning of behaviour and in the regulation of the basal forebrain cholinergic neurons. During development and adult life nerve growth factor regulates brain expression of neurotransmitters and the stimulation of progenitor cells (stem cells) which, under different external stimuli, may differentiate into neuronal and/or glial cells promoting the recovery of the injured brain. However, little information is available for the aged brain. Thus in the present study we investigated the effect of the social status ('dominance' vs. 'submission') in the aged mouse on the presence of nerve growth factor, brain-derived neurotrophic factor, choline acetyltransferase, neuropeptide Y and progenitor cells of selected brain regions. We found that aged dominant mice showed increased brain-derived neurotrophic factor in the subventricular zone and hippocampus and increased choline acetyltransferase in the septum and basal nuclei, which were associated with increased presence of progenitor cells in the subventricular zone. Conversely, in aged subordinate mice the data showed a marked brain increase in nerve growth factor in the subventricular zone and hippocampus, choline acetyltransferase in the septum and basal nuclei and neuropeptide Y in the hippocampus and parietal cortex. The possible functional implications of these findings are discussed.

Aging↗

PubMed2002

Brain NGF and EGF administration improves passive avoidance response and stimulates brain precursor cells in aged male mice.

Nerve growth factor (NGF) has been shown to improve damage in spatial cognition following aging, whereas epidermal growth factor (EGF) is important in brain cell proliferation. It is also known that the adult mammalian central nervous system contains persistent progenitor cells with characteristics of stem cells. These studies suggest that under appropriate external stimuli progenitor cells may generate neuronal and glial cells promoting recovery of the injured nervous system. However, little is known about the presence and responsiveness of progenitor cells in the aged brain. In the present investigation, we studied the effect of brain intracerebroventricular injections of EGF and/or NGF on progenitor cells of the subventricular area (SVZ) in aged male mice to test learning performances in the passive avoidance apparatus. We found that neither NGF nor EGF improved learning responses. However, combined NGF and EGF administration in the brain improved learning responses of aged mice in the passive avoidance when compared with aged matched nontreated controls. These findings resulted to be associated with increased immunopositivity to progenitor cells in the SVZ. The possible functional implications of these data are discussed.

Aging↗

PubMed2002

Short-term hypergravity influences NGF and BDNF expression, and mast cell distribution in the lungs and heart of adult male mice.

In this study we investigate the effects of short-term hypergravity on lung and heart neurotrophins and mast cell distribution. Our results showed that brain derived-neurotrophic factor (BDNF) protein and mRNA expression are increased in the lungs of mice exposed to hypergravity while in the heart hypergravity causes a marked reduction in BDNF mRNA expression, and a decrease in BDNF protein. Compared to controls, nerve growth factor (NGF) protein was expressed more in the heart of rotated mice. These observations demonstrate that altered hypergravity can affect, though differentially, the local expression of NGF and BDNF proteins and their mRNAs in the lung and heart and indicates that short-term exposure to hypergravity causes a marked increase in BDNF, but not in NGF in the lungs of adult mice. Moreover, mast cells, which are NGF-producing cells and implicated in cardiac and respiratory activity, increased in number in proximity to blood vessels in the heart and in lung airway epithelium of rotated mice. This study indicates that hypergravity influences cardiovascular and respiratory tissue and suggests a neurotrophin involvement in the reaction to this environmental exposure.

Animals↗