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OBJECTIVE AND METHODS: The reeler heterozygous (HZ) mice have provided a model for studying the relationship between reelin (a protein of extracellular matrix) haploinsufficiency and the emergence of neuropsychiatric diseases. In a neurodevelopmental framework, the enduring consequences of early maternal separation (5 h/day during the first postnatal week, or handling controls, H) were studied in reeler HZ and wild type (WT) mice at adulthood. The modulatory effects of a chronic treatment with the atypical antipsychotic olanzapine (OLZ, 1.5 mg/kg for 40 days) were also investigated. RESULTS: Early maternal separation had long-term effects on brain plasticity, with a reduction of brain- and glial- derived neurotrophic factor (BDNF and GDNF) in several brain areas of mice, but such a consequence was less marked in the HZ genotype. On the other hand, treatment with OLZ did not affect at all the GDNF but led to an increase of BDNF levels in maternally separated (SEP) mice, an effect which was far more marked in the HZ genotype. Brain levels of serotonin (5-HT) were markedly increased, striatal dopamine (DA) was increased, whereas metabolites and turnover were decreased, in SEP mice of both genotypes. The spontaneous home-cage activity was generally lower in HZ than WT mice, and OLZ treatment contrasted this hypoactivity profile. Maternal separation also decreased the interest toward an unknown mouse proposed as a social stimulus, but only in WT mice. CONCLUSION: We investigated the interplay between genetic vulnerability (reelin haploinsufficiency), the outcome of early stressful experiences, and the efficacy of the antipsychotic drug therapy. The reeler HZ genotype exhibited a slightly lower sensitivity to the environmental insult as well as an enhanced response to the atypical antipsychotic treatment.

Background Aim of this study was to investigate the retrograde axonal transport from optic nerve (ON) to retinal ganglion cell (RGC) in two animal models: in Royal College of Surgeons (RCS) rats, a rat model for retinal degeneration, and in a rat model for glaucoma induced by elevated intraocular pressure (IOP). Methods To carry out this study, dextran tetramethylrhodamine (DTMR- an hydrophilic neurotracer dye) was injected into the ON; 24 hrs later, the retina was removed and the number of labeled RGCs of the experimental rats was counted and compared. Results The results of these studies showed that the number of fluorescent-labeled RGCs in RCS rats and in rats with elevated IOP was reduced compared to the number of labeled RGCs of their respective controls. Conclusion Our findings suggest that RCS rats are characterized not only by loss of photoreceptor cells but also by functional deficits of RGCs.

The acute involution of the thymus is induced by either exogenous or endogenous factors, including some infections (infection type involution). The present study was focused on both detection and immunocytochemical analysis of NGF immunopositive mast cells in child thymus with acute infection-induced involution. Autopsy thymus specimens from children with infection diseases (Sepsis, Encephalomyelitis, Varicella) were examined at light and electron microscopic level and compared to normal infantile thymuses. We observed a redistribution of NGF immunopositive mast cells in infection-affected child thymus, which lobular architecture was collapsed. A positive correlation between the degree of the involutive changes, increased distribution and enhanced NGF immunoreactivity of mast cells was defined. The possible involvement of NGF immunopositive mast cells in the process of acute thymus involution is discussed.

Nerve growth factor (NGF) is the prototype of the neurotrophin family and promotes the survival of specific populations of neurons, stimulates their morphological differentiation and regulates neuronal gene expression. Since its discovery, NGF attracted clinicians for its potential application in the treatment of neurological disorders. Recent studies demonstrated murine NGF eye drops may be successfully used to treat neurotrophic keratopathy. Neurotrophic keratopathy is a degenerative corneal disease caused by an impairment of the trigeminal nerve, which leads to corneal epithelial defect, ulcer, and perforation. NGF topical application induced complete ulcer healing and a recovery of the corneal sensitivity. The intent of this study is to address the question if murine NGF topical treatment stimulates the production of circulating anti-NGF antibodies. We evaluated patients with neurotrophic keratopathy who underwent topical therapy with NGF eye drops for possible ocular or systemic adverse effects in the course of 16-72 months follow up. None of the patients suffered any adverse reaction, except for mild and transient conjunctival hyperaemia and photophobia. Moreover, none of the treated patients developed circulating antibodies to NGF.

Changes during gestation have been shown to induce brain maldevelopment associated with changes in neurotrophins as nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neuropsychiatric disorders in humans. A rat model of altered prenatal brain development resembling the onset of schizophrenia has been obtained by administering in fetus methylazoxymethanol (MAM) at gestational day 12 which impairs the growth of limbic pathways between the entorhinal cortex and the hippocampus. Using the MAM model we studied in young rats the brain levels of both NGF/BDNF and their main receptors, TrkA/TrkB, to investigate whether or not changes in neurotrophins could affect the presence of brain BrdU positive cells. We found increased NGF and BDNF protein levels, associated with elevated TrkA and TrkB expression, in the hippocampus, entorhinal cortex, olfactory lobes and subventricular zone (SVZ), brain areas playing a key role in the production and migration of new dividing cells. We also found higher levels of BrdU positive cells in the SVZ and hippocampus but not a significant potentiation in the entorhinal cortex and olfactory lobes. All together the findings indicate that prenatal MAM exposure in young rats may elicit both neurotrophins' elevation and cell proliferation in limbic brain areas.

Our acute awareness of the cosmetic, psychosocial and sexual importance of subcutaneous adipose tissue contrasts dramatically with how poorly we have understood the biology of this massive, enigmatic, often ignored and much-abused skin compartment. Therefore, it is timely to recall the exciting, steadily growing, yet underappreciated body of evidence that subcutaneous adipocytes are so much more than just 'fat guys', hanging around passively to conspire, at most, against your desperate attempts to maintain ideal weight. Although the subcutis, quantitatively, tends to represent the dominant architectural component of human skin, conventional wisdom confines its biological key functions to those of energy storage, physical buffer, thermoregulation and thermoinsulation. However, already the distribution of human superficial adipose tissue, by itself, questions how justified the popular belief is that 'skin fat' (which actually may be more diverse than often assumed) serves primarily thermoinsulatory purposes. And although the metabolic complications of obesity are well appreciated, our understanding of how exactly subcutaneous adipocytes contribute to extracutaneous disease - and even influence important immune and brain functions! - is far from complete. The increasing insights recently won into subcutaneous adipose tissue as a cytokine depot that regulates innate immunity and cell growth exemplarily serve to illustrate the vast open research expanses that remain to be fully explored in the subcutis. The following public debate carries you from the evolutionary origins and the key functional purposes of adipose tissue, via adipose-derived stem cells and adipokines straight to the neuroendocrine, immunomodulatory and central nervous effects of signals that originate in the subcutis - perhaps, the most underestimated tissue of the human body. The editors are confident that, at the end, you shall agree: No basic scientist and no doctor with a serious interest in skin, and hardly anyone else in the life sciences, can afford to ignore the subcutaneous adipocyte - beyond its ample impact on beauty, benessence and body mass.

Early life experiences, such as early handling, can influence neural development of rodents leading to changes in physiological and behavioural reactivity to stress. These effects are likely to be mediated by changes in maternal behaviour. This study analyzed the effects of different manipulations of the rearing environment on maternal behaviour and the behavioural and physiological response to mild challenges in CD-1 mouse pups early during development. Litters underwent either 15 min of neonatal handling (H) or were exposed briefly to an unfamiliar male intruder from postnatal (PND) days 2 to 14 (MI). Both groups were compared with litters which were not manipulated (NH). Compared to NH subjects, licking behaviour in the MI group was increased only on the first day of introduction of the male intruder, while the H group showed an increase in maternal behaviour on PND 10. On PND 8, pups ultrasonic vocalizations were recorded upon treatment with an anxiolytic drug (chlordiazepoxide 0, 2, or 7.5mg/kg). Results indicate that, although there were no differences among the groups when mice were injected with vehicle, handled subjects did not reduce their calling rate following drug administration, in contrast to the NH and MI groups. Following maternal separation and novelty exposure on PND 9, levels of hippocampal NGF increased significantly only in the H group. These data suggest that active pup manipulations in the form of handling favour behavioural and neural plasticity resulting in the maintenance of a high level of arousal and in increased neurotrophin levels in response to an acute manipulation. Changes in hippocampal levels of NGF might be involved in the appraisal of subtle changes in the early social environment.

BACKGROUND: Nerve growth factor (NGF) has been indicated to be critical to normal renal development in rodents. However, little is known about the expression of NGF and the high-affinity NGF receptors in human kidneys which is essential for promoting the biological and functional activities of NGF. The present study examined the presence of NGF, low-affinity (p75) and high-affinity tyrosine kinase A (TrkA) NGF receptor (NGFR) immunoreactivity in diseased human kidneys. METHODS: Renal biopsies were performed in 24 patients (11 females and 13 males, ranging from 12 to 78 years of age), with various renal diseases. Kidney biopsy samples were fixed in Bouin fluid for 24 hours, washed, dehydrated, embedded in paraplast sections (3-micron thick) and immunostained for NGF, TrkA and p75 localization. Immunostained sections were evaluated under a Nikon Eclipse E600 microscope equipped with a x20 objective and a Nikon DMX 1200 digital camera connected to a PC computer, with the aid of a computerized image analysis system. RESULTS: The results demonstrate the existence of NGF and TrkA in tubular and glomerular cells and of p75-positivity in the interstitial and mesangial cells. It also shows colocalization of TrkA and NGF, but not TrkA and p75 in tubular and glomerular cells, implying that the synthesis and utilization of NGF might be autocrinally regulated. CONCLUSIONS: These findings suggest that NGF signaling may be important in human kidney and glomerular response to injury, though to understand the precise functional significance of these NGF elements in the human kidney, further studies need to be done.

We investigated immunoreactivity for p75 neurotrophin receptor (NTR)in the spinal cord white matter and septum of rats made cobalamin-deficient (Cbl-D) by means of total gastrectomy or a Cbl-D diet. Cbl deficiency down-regulates p75NTR-immunoreactive cell levels in spinal cord white matter and septum with different time courses. On the whole, the spinal cord white matter seems to be more affected in terms of p75NTR-immunoreactive cells, most of which are astrocytes. The p75NTR-immunoreactive cell levels in the spinal cord white matter and septum normalized in rats treated with Cbl (scheme b) and killed 4 months after total gastrectomy. However, Western blot analysis of p75NTR in the spinal cords of Cbl-D rats shows increased p75NTR protein levels, which are resistant to Cbl replacement. These findings demonstrate that a neurotrophic vitamin (Cbl) positively regulates the levels of a neurotrophic receptor (p75NTR) (at least in terms of immunohistochemistry) in rat central nervous system, although the underlying mechanism(s) are still unknown.

Nerve growth factor (NGF) serum levels were measured in 49 patients with asthma and/or rhinoconjunctivitis and/or urticaria-angioedema. Clinical and biochemical parameters, such as bronchial reactivity, total and specific serum IgE levels, and circulating eosinophil cationic protein levels, were evaluated in relation to NGF values in asthma patients. NGF was significantly increased in the 42 allergic (skin-test- or radioallergosorbent-test-positive) subjects (49.7 +/- 28.8 pg/ml) versus the 18 matched controls (3.8 +/- 1.7 pg/ml; P < 0.001). NGF levels in allergic patients with asthma, rhinoconjunctivitis, and urticaria-angioedema were 132.1 +/- 90.8, 17.6 +/- 6.1, and 7.6 +/- 1.8 pg/ml (P < 0.001, P < 0.002, and P < 0.05 versus controls), respectively. Patients with more than one allergic disease had higher NGF serum values than those with a single disease. When asthma patients were considered as a group, NGF serum values (87.6 +/- 59.8 pg/ml) were still significantly higher than those of control groups (P < 0.001), but allergic asthma patients had elevated NGF serum levels compared with nonallergic asthma patients (132.1 +/- 90.8 versus 4.9 +/- 2.9 pg/ml; P < 0.001). NGF serum levels correlate to total IgE serum values (rho = 0.43; P < 0.02). The highest NGF values were found in patients with severe allergic asthma, a high degree of bronchial hyperreactivity, and high total IgE and eosinophil cationic protein serum levels. This study represents the first observation (that we know of) that NGF is increased in human allergic inflammatory diseases and asthma.

Nerve growth factor (NGF) is an endogenously produced growth factor regulating survival not only of nerve cells, but also of cutaneous tissues. We have recently reported that NGF can promote healing of human corneal ulcer, and cutaneous diabetic and pressure ulcers. In this study, we present a case report showing that NGF can induce recovery of a chronic cutaneous ulcer that failed to respond to all available therapies, including autologous skin transplantation. The result showed that topical application of NGF for 3 consecutive months induced skin ulcer healing and reduced the local inflammation. This finding supports and extents previous studies suggesting the cutaneous healing action and the potential therapeutic role of NGF.

Since NGF is an essential factor regulating survival and differentiation of neuronal progenitors in the peripheral and central nervous system, the aim of our study was to investigate whether NGF and its receptors are involved in the differentiation of human neural stem cells in vitro. Human neural stem/ progenitor cells derived from foetal cortex were cultured as neurospheres in defined conditions with mitogens and induced to differentiate by plating without mitogens on adherent surfaces with or without NGF. The differentiation stages and cell phenotypes were identified by the expression of neural markers such as Pax6, nestin, vimentin and GFAP for neuroepithelial and radial glial cells, and betaIII-tubulin, MAP2 and ChAT for neuronal cells. These cell populations were analyzed for the expression of the NGF specific receptor TrkA and the pan-neurotrophin receptor p75. The data obtained using RT-PCR and Real-Time PCR, double and triple immunofluorescence analyzed by confocal microscopy and flow-cytometry indicated that the expression of TrkA and p75 was not homogeneous in human stem/progenitor cells and their temporal expression was correlated with the differentiation stage and cell phenotype. TrkA and p75 were both expressed in neurospheres, in nestin positive cells, but after their plating, while p75 was not expressed, TrkA was highly up-regulated in the radial glial cells co-expressing vimentin and GFAP. This temporal expression of NGF receptors indicates a different NGF dependence of human progenitor cells and suggests that NGF can regulate differentiation of human neural stem and progenitor cells towards specific neuronal populations. Dr Nat is a recipient of a CNR-NATO fellowship. published in FENS Forum Abstracts, vol. 3, 2006. Ref.: FENS Abstr., vol.3, A124.12, 2006

Rationale: Nerve growth factor and its receptors are upregulated in the lungs of weanling rats with lower respiratory tract infection caused by the respiratory syncytial virus (RSV), and this is a major mechanism of the inflammatory response against the virus. However, no information is available in humans. Objectives: We sought to determine whether the expression of neurotrophic factors and receptors is increased in human infants infected with RSV. Methods: We used a highly sensitive immunoassay to measure the concentrations of nerve growth factor and brain-derived neurotrophic factor proteins in serum samples and in the supernatants and cell fractions of nonbronchoscopic bronchoalveolar lavage fluid. We also used immunofluorescence to detect expression in airway cells of the tyrosine kinase receptor TrkA, which binds nerve growth factor with high affinity. Samples were obtained at 24 and 48 hours postintubation from 31 mechanically ventilated infants: 15 patients with RSV infection, 5 patients with respiratory infection negative for RSV, and 11 postsurgical patients without respiratory infection. Main Results: Data show significantly higher concentrations of both neurotrophins in the cell fractions of bronchoalveolar lavage samples obtained from infants with RSV infection compared with control infants, whereas no significant difference was found in supernatants or serum samples. We also detected tyrosine kinase receptor immunoreactivity only in cells from airways infected with RSV. Conclusions: We conclude that neurotrophic factors and receptors are overexpressed in human airways infected by RSV, and may contribute to airway inflammation and hyperreactivity.

BACKGROUND: Estradiol valerate (EV)-induced polycystic ovaries (PCO) in rats is associated with an increase in ovarian sympathetic outflow. Low-frequency (2 Hz) electro-acupuncture (EA) has been shown to modulate sympathetic markers as well as ovarian blood flow as a reflex response via the ovarian sympathetic nerves, in rats with EV-induced PCO. METHODS: In the present study, we further tested the hypothesis that repeated 2 Hz EA treatments modulate ovarian sympathetic outflow in rats with PCO, induced by a single i.m. injection of EV, by investigating the mRNA expression, the amount and distribution of proteins of alpha1a-, alpha1b-, alpha1d-, and beta2-adrenoceptors (ARs), as well as the low-affinity neurotrophin receptor (p75NTR). RESULTS: It was found that EV injection results in significantly higher mRNA expression of ovarian alpha1b- and alpha1d-AR in PCO rats compared to control rats. The p75NTR and beta2-ARs mRNA expression were unchanged in the PCO ovary. Low-frequency EA resulted in a significantly lower expression of beta2-ARs mRNA expression in PCO rats. The p75NTR mRNA was unaffected in both PCO and control rats. PCO ovaries displayed significantly higher amount of protein of alpha1a-, alpha1b- and alpha1d-ARs, and of p75NTR, compared to control rats, that were all counteracted by repeated low-frequency EA treatments, except for alpha1b-AR. CONCLUSION: The present study shows that EA normalizes most of the EV-induced changes in ovarian ARs. Furthermore, EA was able to prevent the EV-induced up regulation of p75NTR, probably by normalizing the sympathetic ovarian response to NGF action. Our data indicate a possible role of EA in the regulation of ovarian responsiveness to sympathetic inputs and depict a possible complementary therapeutic approach to overcoming sympathetic-related anovulation in women with PCOS.

In the present study, we aim to show that non-adherent bone marrow cells (BMCs) express TrkA, the nerve growth factor (NGF) receptor, and that addition of NGF promotes the survival and neuronal commitment of BMC transplanted into the experimentally injured brain of littermates mice. Immunohistochemical analysis revealed that transplanted BMCs express tyrosine hydroxylase (TH) in proximity of the damaged dopaminergic tissues and choline acetyltransferase (ChAT) in the lesioned cholinergic regions. These results suggest that NGF supports the survival and differentiation of uncommitted BMCs and concurs with other local environmental signals to promote the expression of neuronal markers in these cells. The possible functional significance of these observations will be discussed.

A growing number of studies on inflammatory diseases have demonstrated that the inflammatory state is characterised by up-regulation of Nerve Growth Factor (NGF) synthesis. In addition, purified immune cells involved in innate and acquired immunity show a basal expression of NGF, whose synthesis is enhanced after stimulation with specific antigens and cytokines. In spite of the large number of studies, it is still not clear why NGF is produced in vivo during the inflammation process and how its local synthesis, often in an autocrine fashion, can influence the ongoing immune response. We recently showed that the autocrine NGF synthesis in B-lymphocytes directly regulates the expression and release in these cells of calcitonin gene-related peptide (CGRP), a neuropeptide able to inhibit immune response, suggesting a possible NGF anti-inflammatory action. To test this hypothesis we investigated whether endogenous NGF can regulate the synthesis of CGRP in monocytes and how the autocrine synthesis of either NGF or CGRP can influence monocyte functions. For this study we used human monocytes purified from buffy-coats by Percoll gradients and immunomagnetic negative selection and cultured in the presence or absence of 100ng/ml LPS, with or without the addition of 100ng/mlNGF or 10?g/ml neutralizing anti-NGF antibodies or isotypic IgG or CGRP8-37. CGRP expression was analyzed by RT-PCR, immunofluorescence and flow cytometry analysis. Our results showed that monocytes synthesise basal levels of CGRP and after LPS stimulation, CGRP expression is up-regulated. Endogenous NGF production, induced in monocytes by LPS stimulation, regulates CGRP synthesis. Using neutralizing anti-NGF antibodies, the expression of CGRP decreases in resting cells and the up-regulation of CGRP induced by LPS is prevented. The neutralization of endogenous NGF significantly enhances CD86 and HLA-DR expression while reducing IL-10 synthesis, and functionally affects antigen presentation as observed in the allogeneic mixed leukocyte reaction. Similar but not identical effects were observed when endogenous CGRP action was blocked by using CGRP8-37, the CGRP receptor I antagonist. Taken together our results show that the endogenous synthesis of NGF in monocytes has a functional role and by reducing the antigen presenting capacity and co-stimulatory function of monocytes NGF can dampen the immune response.

Administration of Nerve Growth Factor (NGF) in EAE models delays the onset and prevents the full development of EAE lesions. In line with the newly found anti-inflammatory activity of NGF are our recent results on the autocrine NGF synthesis in B lymphocytes, which directly regulate in these cells the expression of calciotonin gene-related peptide (CGRP), a neuropeptide which is a potent inhibitor of T cell proliferation and antigen presentation by macrophages and monocytes. Using cultures of human monocytes we investigated by RT-PCR, immunofluorescence and flow cytometry analysis whether NGF can regulate the expression of CGRP also in these cells and influence the expression of B7.1 and B7.2 and IL-10. Our data indicate that monocytes synthesise basal levels of NGF but, after LPS stimulation, up-regulate NGF expression in dose-dependent fashion. When the cultures are deprived of endogenous NGF, CGRP expression in resting cells decreases and the up-regulation of CGRP induced by LPS is prevented. In addition we observed that endogenous NGF reduction affects co-stimulatory molecule expression and IL-10 synthesis, and these effects can be partially mimicked by using CGRP receptor I antagonist. Our findings indicate that endogenous synthesis of NGF in monocytes has a functional role and, by influencing B7.2 expression and IL-10 production, contributes to the down-regulation of the immune response and strongly support the newly found anti-inflammatory activity of NGF.

The development of atherosclerotic cardiovascular disease is a common comorbidity in patients with the metabolic syndrome, a concurrence of cardiovascular risk factors in one individual. While multiple growth factors and adipokines are identified in atherosclerotic lesions, as well as neurotrophins implicated in both cardiac ischemia and lipid and glucose metabolism, the potential role of neurotrophins in human coronary atherosclerosis and in the metabolic syndrome still remains to be elucidated. Here we describe and discuss our results that represent a novel attempt to study the cardiovascular and metabolic biology of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and mast cells (MC). The local amount of NGF, the immunolocalization of p75 neurotrophin receptor (p75NTR) and the number of MC were correlatively examined in coronary vascular wall and in the surrounding subepicardial adipose tissue, obtained from autopsy cases in humans with advanced coronary atherosclerosis. We also analyzed the plasma levels of NGF, BDNF and leptin and the number of MC in biopsies from abdominal subcutaneous adipose tissue in patients with a severe form of the metabolic syndrome. The results demonstrate that NGF levels are decreased in atherosclerotic coronary vascular tissue but increased in the subepicardial adipose tissue, whereas both tissues express a greater number of MC and a stronger p75NTR immunoreactivity, compared to controls. Metabolic syndrome patients display a significant hyponeurotrophinemia and an increased number of adipose MC; the later correlates with elevated plasma leptin levels. In effect, we provide the first evidence for (i) an altered presence of NGF, p75NTR and MC in both coronary vascular and subepicardial adipose tissue in human coronary atherosclerosis, and (ii) a significant decrease in plasma NGF and BDNF levels and an elevated amount of plasma leptin and adipose MC in metabolic syndrome patients. Together our findings suggest that neuroimmune mediators such as NGF, BDNF, leptin and MC may be involved in the development of cardiovascular disease and related disorders.

The effects of MSG treatment on NGF and NPY levels were analysed in the hypothalamus, pituitary, adrenal, thyroid and testis of adult rats. Daily i.v. injections of MSG (1 g kg-1 for 1 week) induced an increase of NGF in the hypothalamus (control (C) = 378 +/- 54; saline (S) = 369 +/- 36; MSG = 479 +/- 35 pg g-1 tissue; p < 0.001) and pituitary (C = 310 +/- 34; S = 376 +/- 114; MSG = 576 +/- 98 pg g-1 tissue; p < 0.01). Hypothalamic and pituitary NPY concentrations were also altered in the MSG-treated rats. Compared with saline-treated rats, the NPY concentration increased by 43% in the hypothalamus and 37.5% in the pituitary of MSG-treated rats. No significant changes in NGF and NPY content were found in the adrenal or thyroid of treated animals. These results suggest that hypothalamic and pituitary NGF and NPY levels may be involved in the control of neuroendocrine functions that are affected by MSG treatment.

Recent evidence indicates that some thymic cells of developing and adult laboratory animals express the neurotrophin NGF and its low-affinity p75NTR and high-affinity TrkA receptor. Less is known as to whether the thymus of adult and aged humans express these markers. We hypothesize that the presence and distribution of immunopositive cells for NGF and NGF receptors undergo some alterations during the involution of human thymus. Specimens from normal thymuses of old individuals were obtained from autopsy and surgery cases, and examined immunocytochemically at the light and transmission electron microscopic level. The immunoreactivity of NGF, p75NTR, TrkA and cytokeratin was found in the epithelial thymocyte microenvironment. Our results provide the first ultrastructural evidence for NGF/receptor immunocytochemical localization in human thymus. They suggest a possible immunotrophic/immunoregulatory role of the NGF-p75NTR-TrkA system for T-cell development in human thymus during senile involution.

Previous studies on the effect of repeated electro-acupuncture (EA) treatments in rats with steriod-induced polycystic ovaries (PCO), EA has been shown to modulate nerve growth factor (NGF) concentration in the ovaries as well as corticotropin releasing factor (CRF) in the median eminence (ME). In the present study we tested the hypothesis that repeated EA treatments modulates sympathetic nerve activity in rats with PCO. This was done by analysing endothelin-1 (ET-1), a potent vasoconstrictor involved in ovarian functions, as well as NGF and NGF mRNA expression involved in the pathophysiological process underlying steroid-induced PCO. The main result in the present study was that concentrations of ET-1 in the ovaries were significantly lower in the PCO group receiving EA compared with the healthy control group (p < 0.05). In the hypothalamus, however, ET-1 concentrations were found to be significantly higher in the PCO group receiving EA than in the healthy control group (p < 0.05). Concentrations of ovarian NGF protein were significantly higher in the PCO control group compared with the healthy control group (p < 0.001), and these concentrations decreased significantly after repeated EA treatments compared with those in the PCO control group (p < 0.05) and were found to be the same as those in the healthy control group. In conclusion, these results indicate that EA modulates the neuroendocrinological state of the ovaries, most likely by modulating the sympathetic nerve activity in the ovaries, which may be a factor in the maintenance of steroid-induced PCO.

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.

In addition to their stimulatory action on neuronal differentiation and survival, the neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) improve glucose and lipid metabolism and control energy balance and feeding behavior. These latter activities are referred to here as the metabotrophic potential of neurotrophins. We recently reported that circulating NGF and BDNF levels are reduced in the metabolic syndrome and in acute coronary syndromes, and that the tissue content of NGF is reduced in atherosclerotic coronary arteries. Thus we hypothesize that a metabotrophic deficit due to reduction of neurotrophin availability may be implicated in the pathogenesis of obesity and related metabolic diseases, such as metabolic syndrome, type 2 diabetes, and atherosclerosis. The metabotrophic deficit hypothesis also considers metabolism-related beneficial effects exerted by other neurotrophic factors, particularly ciliary neurotrophic factor, leukemia inhibitory factor, and bone morphogenetic proteins.

Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are proteins involved in neuronal survival and plasticity of dopaminergic, cholinergic and serotonergic neurons in the central nervous system (CNS). Moreover, it has been hypothesized that these molecules play a role in the pathophysiology as well as treatment of depression. Using an animal model of depression, the Flinders Sensitive Line (FSL) rats and their controls, the Flinders Resistant Line (FRL), we investigated the effects of electroconvulsive stimuli (ECS) on brain NGF and BDNF. ECS or SHAM ECS were administered eight times, with a 48-h interval between each treatment. NGF and BDNF were measured with enzyme-linked immunosorbent assay (ELISA). In the hippocampus ECS increased NGF concentration in FSL but not FRL rats. ECS decreased NGF concentration in the frontal cortex of FSL rats. In both FSL and FRL rats ECS increased NGF levels in the striatum. In contrast, ECS did not change BDNF concentration in hippocampus, frontal cortex and striatum of FSL and FRL rats. Our data support the notion that neurotrophin concentrations may be altered by ECS.

Degenerative diseases represent a severe problem because of the very limited repair capability of the nervous system. To test the potential of using stem cells in the adult central nervous system as "brain-marrow" for repair purposes, several issues need to be clarified. We are exploring the possibility of influencing, in vivo, proliferation, migration, and phenotype lineage of stem cells in the brain of adult animals with selective neural lesions by exogenous administration (alone or in combination) of hormones, cytokines, and neurotrophins. Lesion of the cholinergic system in the basal forebrain was induced in rats by the immunotoxin 192IgG-saporin. Alzet osmotic minipumps for chronic release (over a period of 14 days) of mitogens [epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF)] were implanted in animals with behavioral and biochemical cholinergic defect and connected to an intracerebroventricular catheter. After 14 days of delivery, these pumps were replaced by others delivering nerve growth factor (NGF) for an additional 14 days. At the same time, retinoic acid was added to the rats' food pellets for one month. Whereas the lesion decreased proliferative activity, EGF and bFGF both increased the number of proliferating cells in the subventricular zone in lesioned and nonlesioned animals. These results are indicated by the widespread distribution of BrdUrd-positive nuclei in the forebrain, including in the cholinergic area. Performance in the water maze test was improved in these animals and choline acetyltransferase activity in the hippocampus was increased. These results suggest that pharmacological control of endogenous neural stem cells can provide an additional opportunity for brain repair. These studies also offer useful information for improving integration of transplanted cells into the mature brain.

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

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.

Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) are proteins involved in neuronal survival and plasticity of dopaminergic, cholinergic and serotonergic neurons in the central nervous system. Since decreased size and impaired function of some neuronal populations may be relevant in depression it has been hypothesized that these molecules may have a functional role in the pathophysiology as well as treatment of depression. Using an animal model of depression, the Flinders Sensitive Line (FSL) rats and their controls, the Flinders Resistant Line (FRL), we investigated the effects of chronic lithium treatment on brain NGF, BDNF and GDNF. Lithium was administered as food supplementation during 6 wk. NGF, BDNF and GDNF measurements were performed by enzyme-linked immunosorbent assay (ELISA). Lithium altered the brain concentrations of neurotrophic factors in the hippocampus, frontal cortex, occipital cortex and striatum. Moreover, the changes were different in the two rat strains. Our data support the notion that neurotrophic factors play a role in depression and in the mechanism of the action of lithium.

Aim of this study was to investigate the synthesis, release and effects of nerve growth factor (NGF) in human synovial cells isolated from synovial tissue specimen from healthy and osteoarthritis (OA) patients. METHODS: Human synovial fibroblasts cultures were established starting from healthy and osteoarthritis patients. NGF protein levels in the culture medium, NGFmRNA and high-affinity NGF receptor (Tyrosine kinase A: TrkA) expression in the cells were evaluated in basal conditions and after stimulation with pro-inflammatory cytokines or with the neuropeptide cholecystokinin-8 (CCK-8). The effect of NGF supplement to culture medium on cell proliferation, TrkA expression, and tumour necrosis factor-alpha (TNF-alpha) and inducible-nitric oxide synthase (iNOS) production was investigated. RESULTS: Under basal conditions human synovial cells produce and release NGF. Both interleukin-1-beta (IL-1 beta) and TNF-alpha, but not CCK-8 promote NGF synthesis and release from OA cells. TrkA NGF receptors are also expressed in both normal and OA synovial cells. NGF, but not IL-1 beta, TNF-alpha and CCK-8, enhances the expression of TrkA in isolated synovial cells. NGF down-regulates IL-1 beta-induced TNF-alpha and iNOS production by OA synovial fibroblasts. CONCLUSIONS: NGF is produced and released and TrkA receptors are expressed in synovial inflammation. Overexpression of NGF in inflammed joints might be involved in the modulation rather than in the induction of the joint inflammatory response.