Intranasal self-administration of high-pressure physiological saline isotonic solution ameliorates dry eye symptoms and tear film composition: a pilot study.

OBJECTIVE: High-pressure physiological saline isotonic solution (HPpSIS) delivery into the nasal cavity was found to modulate the local expression of immune cells, increase NGF protein, and enhance the NGF receptors' expression. Since the nasal cavity directly communicates with the eye and as NGF was previously found to ameliorate the symptoms of dry eye when topically delivered, the aim of this study was to establish whether the HPpSIS might ameliorate ocular dryness and tear film composition. SUBJECTS AND METHODS: This is an observational self-controlled case study carried out on 16 patients with dry-eye diagnosis, concerning 3-month self-administration of HPpSIS and two serial assessments of the ocular surface and tear film. OSDI questionnaire was used for ocular symptoms of dryness. BUT and Schirmer tests were used for qualitative and quantitative tear film analysis. The lipid composition was also examined. R-studio was employed for the detection of the difference between the pre- and post-analysis. RESULTS: On the basis of the OSDI questionnaire, the study population was divided into severe (61.1%), moderate (5.5%), and mild (16.6%) dry-eye symptoms. OSDI score was significantly reduced after HPpSIS (p<0.05). BUT and TMH values also ameliorated after HPpSIS (p>0.05), although not significantly. The lipid layer improved statistically (p<0.05) and correlated positively with OSDI grading. The variability of presentation in the numerical distribution before and after therapy suggests poor test sensitivity. CONCLUSIONS: HPpSIS showed a positive effect in reducing OSDI scores and ameliorating tear film quality. The possibility of an endogenous HPpSIS-induced NGF should be taken into account in dry-eye therapy.

Antiviral effect of high-pressure nasal stimulation.

OBJECTIVE: In a previous study, we reported an increase of nasal nerve growth factor (NGF) in patients treated with high-pressure administration of sterile saline isotonic solution (HPpSIS). Herein we characterized the nasal mucosa in terms of innate immune response and cytokine signature, including antiviral properties. Potential NGF and antiviral benefits of HPpSIS were also discussed. PATIENTS AND METHODS: Twenty (20) patients (11 males, 9 females; age range 30-75 years old) underwent HPpSIS and nasal samples were collected before and after treatment. Nasal scraping was used for morphological (smears and Quick May-Grunwald Giemsa staining, MGG), biochemical (Histamine, Serotonin; ELISA) and molecular (messenger RNA, mRNA) analyses. Amplification of transcripts specific for Toll-like receptor (TLR) 3 (TLR3), TLR7, TLR9, Interleukin-(IL) 18 (IL18), IL13, IL12, eosinophil-derived neurotoxin (EDN), Eosinophil Cationic Protein (ECP), γ Interferon (γIFN), tryptase and serotonin was performed using the 2-step real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR). Clinical and laboratory data were analyzed and compared. RESULTS: The clinical evaluation showed a protective effect of our therapy. Smears showed the presence of leucocytes, eosinophils (EOs) and mast cells (MCs), and increased immunoreactivity for ECP/RNase3 and EDN after HPpSIS. ELISA showed increased levels of Serotonin and EDN associated with unchanged levels of substance P(SP) and histamine. Increased eosinophil-derived neurotoxin eosinophil-derived neurotoxin (EDN) levels were confirmed by in situ fluorescent analysis. HPpSIS induced the upregulation of TLR3, TLR7 and TLR9 transcripts, while no changes were observed for Intercellular Adhesion Molecule 1 (ICAM1), IL18, Interleukin-15 (IL15) and IL12 transcripts nor for Interleukin-6 (IL6) and IL13. No changes were also observed for γIFN and EDN/RNase2 transcripts, while ECP/RNase3 transcripts were significantly upregulated after HPpSIS. Finally, tryptase transcripts were unchanged while serotonin transcripts were significantly increased after HPpSIS. CONCLUSIONS: The clinical and biomolecular changes observed at the nasal mucosa due to HpSS treatment suggest the activation of an innate surveillance, by means of TLR transcription, and a possible anti-viral response due to EDN upregulation. It remains to be verified if NGF, known to be released locally upon HpSIS treatment, might in part be responsible for this local activation.

Enhanced presence of serotonin in nasal cavity after autologous stimulation.

OBJECTIVE: Serotonin, which is a vasoactive amine, is an important neurotransmitter and is involved in many behavioral and psychological phenomena, such as pain, appetite, mood, and sleep. The primary purpose of our study was to investigate the effect of high-pressure administration of sterile physiological saline isotonic solution (HpPSIS) into nasal cavity and to determine the expression of the serotonin. PATIENTS AND METHODS: The study was made in two branches, the previous with 14 volunteers, the subsequent study with 40 patients with mild anxiety disorder. The middle third of the inferior turbinate epithelial cells on the right nostril was scraped using a sterile curette and indicated as (pre), then, a spray of sterilized isotonic solution at high pressure on the left nostril was delivered, and 5 minutes later a similar stimulation was delivered on the same nostril. The stimulation was made with a specific spray dispenser. The middle third of the inferior turbinate epithelial cells on the left nostril was scraped using a sterile curette and indicated as (post). Then, based on the first part of our study, we started the second part and gave a treatment on forty new patients with anxiety disorder. RESULTS: The results of these studies highlight the possibility of endogenous enhancement of serotonin by stimulation of mast cells. In the first part of the study, Serotonin significantly increased in protein extracts after treatment (64.35±5.33 vs. 10.97±2.17; unpaired two tailed t-test, t=9.8, df=24, p≤0.0001; F=6.035; DFn=12; DFd=12). In the second part of the study, in patients treated with HpPSIS, we observed improvement of mood, after one, two and three months, with a statistically significant reduction of DASS-21, while no reduction was observed in control patients, treated with normal pressure commercial spray. CONCLUSIONS: This pilot study showed that the topical treatment of HpPHIS increases serotonin levels in nasal cavity. The observation reported in this study opens the way to a new valid strategy to enhance the level of endogenous serotonin. We observed a significant improvement of ASI on patients during HpPHIS therapy.

Keratoconus: the possible involvement of inflammatory cytokines in its pathogenesis. An experimental study and review of the literature.

OBJECTIVE: Keratoconus (KC) is generally described as a non-inflammatory disease, characterized by thinning in the central region of the cornea with consequent tissue degradation producing impaired visual acuity. MATERIALS AND METHODS: In our experimental study, we analyzed the presence and implications of several inflammatory cytokines in the corneal tissues of patients suffering from keratoconus by immunohistochemical analysis. RESULTS: The analysis showed increased levels of inflammatory factors in the pathological tissues compared to controls, confirming that KC cannot be considered an entirely non-inflammatory pathology and that its etiopathogenesis includes several chronic inflammatory events. CONCLUSIONS: In the light of these results, the classification of KC as an inflammatory pathology or as a pathology related to inflammation might be useful in directing future research aimed at developing effective anti-inflammatory therapies to pharmacologically target the inflammatory mediators which contribute to the development and progression of the disease.

The potential role of trans-resveratrol/carboxymethylated (1.3/1.6)-ß-d-glucan minimizing symptoms and improve healing after functional endoscopic sinus surgery.

OBJECTIVE: This study aims to evaluate the effect of trans-resveratrol/carboxymethylated (1.3/1.6)-ß-d-glucan administered via nasal, after FESS, assessing nasal respiratory distress and nasal mucosa healing. PATIENTS AND METHODS: We enrolled 70 patients, from March 2019 to February 2020, with chronic nasal obstruction not responding to medical therapy and candidates to endoscopic nasal surgery. Patients were divided in two non-randomized groups: group A treated with trans-resveratrol/carboxymethylated (1.3/1.6)-ß-d-glucan administered via nasal, and group B treated with 0.9% nasal irrigation saline. Patients were clinically evaluated, in post-operative period, at 7 (T0), 15 (T1), and 30 days (T2) with fibroendoscopy. The CRS (chronic rhinosinusitis) questionnaire (Snot 20) was administrated at T0, T1, and T2. The findings were scored with respect to middle turbinate edema. In both Groups, the inferior turbinate's medial aspect was scraped using a sterile disposable Rhino-probe mucosal curette (Arlington Scientific, Inc., Springville, UT, USA) at T0, T1, and T2. RESULTS: Group A showed an improvement in Snot 20 in T1 and T2 both. The reduction of the mucosal edema and nasal secretion has been statistically significant in the Group A. A slight cell reduction was observed at T2 with respect to T1. This decreased pattern is more evident in nasal scraping from Group A. The appearance of epithelial cells at T2 of Group A is consistent with the reduction of inflammatory cells. CONCLUSIONS: We can assert that in Group A it appears less evident the presence of edema, nasal congestion and crusts, resulting in a quick recover.

The role of inflammation in diabetic retinopathy: a review.

OBJECTIVE: Diabetic retinopathy and diabetes represent serious health conditions, being considered among the main causes of blindness. In recent years, anti-VEGF therapies have been of great help in the treatment of retinal pathology and, until now, they represent the primary choice therapy for diabetic retinopathy. Nevertheless, many patients do not experience significant benefits of vision after an anti-VEGF monotherapy. For this reason, several researchers recently focused their attention on the mechanisms that play a central role in the development and progression of diabetic retinopathy. RESULTS: Available scientific evidence confirms that diabetic retinopathy requires other molecules capable of modifying the mechanisms that, together with angiogenesis, contribute to the development of the condition, such as vascular and neuroinflammation. CONCLUSIONS: This review summarizes the current knowledge of the pathological changes that occur in diabetic retinopathy and that might contribute to identify possible new strategies for the treatment of this condition.

Particle-in-cell Simulations of the Whistler Heat-flux Instability in Solar Wind Conditions.

In collision-poor plasmas from space, e.g., solar wind or stellar outflows, the heat flux carried by the strahl or beaming electrons is expected to be regulated by the self-generated instabilities. Recently, simultaneous field and particle observations have indeed revealed enhanced whistler-like fluctuations in the presence of counter-beaming populations of electrons, connecting these fluctuations to the whistler heat-flux instability (WHFI). This instability is predicted only for limited conditions of electron beam-plasmas, and has not yet been captured in numerical simulations. In this Letter we report the first simulations of WHFI in particle-in-cell setups, realistic for the solar wind conditions, and without temperature gradients or anisotropies to trigger the instability in the initiation phase. The velocity distributions have a complex reaction to the enhanced whistler fluctuations conditioning the instability saturation by a decrease of the relative drifts combined with induced (effective) temperature anisotropies (heating the core electrons and pitch-angle and energy scattering the strahl). These results are in good agreement with a recent quasilinear approach, and support therefore a largely accepted belief that WHFI saturates at moderate amplitudes. In the anti-sunward direction the strahl becomes skewed with a pitch-angle distribution decreasing in width as electron energy increases, which seems to be characteristic of self-generated whistlers and not to small-scale turbulence.

Age-related ultrastructural and monoamine oxidase changes in the rat optic nerve.

The aim of this paper is to study the morphology and the distribution of the monoamine oxidase enzymatic system in the optic nerve of 4 month-old Wistar (young) and 28 month-old Wistar (old) rats. The optic nerve was harvested from 20 young and old rats. The segment of optic nerve was divided longitudinally into two pieces, each 0.1 mm in length. The first piece was used for transmission electron microscopy. The second piece was stained with histochemical reaction for monoamine oxidase. The agerelated changes in the optic nerve of rats include micro-anatomical details, ultrastructure and monoamine oxidase histochemical staining. A strong decrease of the thin nerve fibers and a swelling of the thick ones can be observed in optic nerve fibers of old rats. Increased monoamine oxidase histochemical staining of the optic nerve of aged rats is well demonstrated. The increase of meningeal shealth and the decrease of thin nerve fibers of the optic nerve in old rats are well documented. Morphological, ultrastructural and histochemical changes observed in optic nerve fibers of the old rats show a close relation with aging.

Current progress of Reelin in development, inflammation and tissue remodeling: from nervous to visual systems.

Reelin is a matrix glycoprotein that plays a pivotal role for the positioning of neurons throughout brain development. In the early developing cortex Reelin regulates radial migration of cortical neurons while later in development, Reelin promotes maturation of dendrites and dendritic spines. Low Reelin levels characterize healthy adult brain while increased Reelin levels have been associated with cellular events underlying response to injury. Reelin has been detected in structural and immune cells outside brain (liver, gut/colon tracts, kidney, testis, ovary, lung, retina and cornea). In the Visual system, Reelin was first described in the retina and thereafter in the cornea. Increased Reelin levels were observed during retinogenesis, low levels were found in adulthood and a significant increase was detected upon injury. Insult-driven Reelin changes occur after upregulation of adhesion molecules, cytokines, neurotrophins, growth factors, neuropeptides and other mediators as well as their receptors. These soluble factors contribute to the development of nervous and visual system and promote survival/recovery of neurons/accessory cells populating the injured visual system. Likewise, Reelin might modulate these factors by driving different multiple effects on homeostasis/plasticity, inflammation, healing and remodeling at different physiopathological levels. Very low-density lipoprotein receptor, apolipoprotein E receptor 2, integrins and the adaptor molecule Disabled 1 trigger Reelin. Recent advances highlight some Reelin activities during inflammation and tissue remodeling and point out to a crucial Reelin activity in the visual system. A better understanding of Reelin function in retinal development might open to new attractive perspective for counteracting retina degeneration.

Corneal ulcer as an atypical presentation of ocular cicatricial pemphigoid.

PURPOSE: To describe three patients, each presenting noninfective corneal epithelial damage as first manifestation of ocular cicatricial pemphigoid (OCP). METHODS: Case report. RESULTS: Patients 1 and 2 were referred to the authors' clinic for corneal ulcer while Patient 3 for relapsed epithelial defects. All patients had negative history for systemic diseases and microbiological tests were negative. Topical steroid treatment induced the complete resolution of corneal damage. During the follow-up period, the onset of mild conjunctival fibrosis in the lower fornix allowed the authors to suspect OCP, confirmed by conjunctival biopsy. CONCLUSIONS: In the three patients corneal damage was an early sign of OCP, in the absence of typical signs of conjunctival fibrosis. The authors thus suggest considering conjunctival biopsy as a useful additional test in the management of idiopathic corneal ulcers.

Upregulation of ICAM-1 expression in the conjunctiva of patients with chronic graft-versus-host disease.

PURPOSE: To correlate conjunctival intercellular adhesion molecule 1 (ICAM-1) expression with cytologic and clinical findings of chronic graft-versus-host disease (GVHD). METHODS: Seven patients with chronic GVHD-related keratoconjunctivitis and five age-matched normal controls were recruited for the study. Clinical examination included medical history, visual acuity, evaluation of ocular signs and symptoms (scored from 0 to 3), corneal fluorescein staining (scored from 0 to 5 on the basis of the number of corneal sectors involved), Schirmer test type I, and break-up time (BUT). Impression cytology samples were collected from the nasal and inferior bulbar conjunctiva of patients and controls. Goblet cells were counted in three randomly selected fields and averaged. Immunofluorescent staining for ICAM-1 was carried out and the percentage of cells expressing the marker was evaluated. RESULTS: All patients showed signs and symptoms of keratoconjunctivitis sicca. Schirmer test type I and BUT were reduced (4.8+/-6.7 mm/5 min and 3.9+/-2.7 seconds, respectively). Goblet cells were significantly reduced in GVHD eyes with respect to normal eyes (65+/-30.5 and 192+/-16.9 cells/field respectively; p<0.001). Goblet cell number was directly related to Schirmer test values (p<0.01, rho=0.817) and inversely related to total sign score (p<0.01, rho=-0.939). ICAM-1 expression was increased in GVHD eyes with respect to normal controls, in which no staining was observed. ICAM-1 expression showed an inverse relation to goblet cell number (p<0.01, rho=-0.852) and Schirmer test values (p<0.01, rho=-0.926), and was directly correlated to total sign score (p<0.01, rho=0.982). CONCLUSIONS: Conjunctival ICAM-1 expression is increased in GVHD patients. The severity of the disease is associated with tear parameters, goblet cell decrease, and inflammatory markers, such as ICAM-1.

The pro-fibrogenic effect of nerve growth factor on conjunctival fibroblasts is mediated by transforming growth factor-beta.

BACKGROUND: Nerve growth factor (NGF) and nerve growth factor receptor (NGFR) expressions have been found to be increased in sub-conjunctival scarring. OBJECTIVE: The aim of this study was to investigate the in vitro effects of NGF on some pro-fibrogenic properties of human conjunctival fibroblasts. METHODS: Expression of NGF, trkA(NGFR) and p75NTR on human fibroblasts grown from conjunctival biopsies and incubated for 2 or 6 days with NGF were evaluated by immunofluorescence, RT-PCR, flow cytometry and ELISA. The fibrogenic effect of NGF on conjunctival fibroblasts was investigated by evaluating their migration (wound model), proliferation ([3H]-thymidine incorporation), collagen production (3H]-proline incorporation), expression of alpha-smooth muscle actin (alpha-SMA) (cell surface ELISA) and contraction of 3D collagen gels. RESULTS: NGF induced the expression of p75NTR in the fibroblasts that constitutively expressed only trkA(NGF) and increased the migration of wounded fibroblasts, but not their proliferation and collagen production. NGF induced the conversion of fibroblasts into myofibroblasts expressing alpha-SMA, and enhanced their contraction of a collagen matrix. Interestingly, chronic NGF treatment induced transforming growth factor-beta1 (TGF-beta1) production by fibroblasts, and following specific TGF-beta neutralization, all the NGF-induced effects were completely abrogated. CONCLUSION: Our findings indicate that NGF, via TGF-beta induction, is likely to be involved in the healing or fibrotic processes occurring in conjunctiva during some pathological conditions.

Nerve growth factor and asthma.

An increasing body of evidence shows that nerve growth factor (NGF) exerts biological activity not only on the central and peripheral nervous system, but also on the immune system thereby influencing allergic diseases and asthma. (1) NGF circulating levels are increased in patients with allergic diseases and asthma, and are related to the severity of the inflammatory process and disease. In vernal keratoconjunctivitis, NGF plasma levels correlate with the number of mast cells infiltrating the conjunctiva, and NGF mRNA is increased in nasal mucosal scrapings of patients with allergic rhinitis who have high levels of NGF in serum and nasal fluids; NGF is further increased in nasal fluids after specific allergen challenge. (2) NGF is produced and released by several modulatory and effector cells of allergic inflammation and asthma, for example T-helper 2 lymphocytes, mast cells and eosinophils. (3) NGF receptors are expressed on the conjunctival epithelium of patients with allergic conjunctivitis and the number of NGF-receptor positive cells is increased in the conjunctiva of these patients. Indeed, local administration of NGF induces fibroblast activation and healing processes of human corneal ulcers, which suggests that NGF plays a role in tissue remodelling processes occurring in asthma. (4) NGF increases airway hyperreactivity to histamine in an animal model of asthma, while anti-NGF treatment reduces airway hyperreactivity induced by ovalbumin topical challenge in the sensitized mouse.

The upregulation of nerve growth factor receptors in reactive astrocytes of rat spinal cord during experimental autoimmune encephalomyelitis.

Using immunocytochemistry, we have examined the effect of experimental autoimmune encephalomyelitis (EAE) upon the expression of nerve growth factor (NGF) and its TrkA and p75 receptors in astroglia cells of the spinal cord of Lewis rats. We have found that, in normal spinal cord, astroglia of white matter expressed both NGF receptors while those in gray matter expressed only TrkA and no astroglia expressed NGF. During EAE, strong upregulation of TrkA in the astroglia of gray and white matter was found, particularly in a population of radially oriented astrocytes. An upregulation of p75 was noted in radial astroglia and, to some extent, also in the stellate astrocytes of white matter. In general, the upregulation of NGF receptor immunoreactivities in astroglia correlated with the strong intensification of glial fibrillary acidic protein immunocytochemistry, a prominent feature of EAE. No NGF immunoreactivity appeared in any astroglia cells during EAE. Our results suggest that, during EAE, astroglia of the spinal cord become particularly receptive to NGF, possibly as part of a mechanism enabling astroglial cells to respond to localized release of neurotrophins. Moreover, our data suggest that spinal cord astroglia cells may be a potential target for pharmacological manipulations in EAE.

Nerve growth factor displays stimulatory effects on human skin and lung fibroblasts, demonstrating a direct role for this factor in tissue repair.

Nerve growth factor (NGF) is a polypeptide which, in addition to its effect on nerve cells, is believed to play a role in inflammatory responses and in tissue repair. Because fibroblasts represent the main target and effector cells in these processes, to investigate whether NGF is involved in lung and skin tissue repair, we studied the effect of NGF on fibroblast migration, proliferation, collagen metabolism, modulation into myofibroblasts, and contraction of collagen gel. Both skin and lung fibroblasts were found to produce NGF and to express tyrosine kinase receptor (trkA) under basal conditions, whereas the low-affinity p75 receptor was expressed only after prolonged NGF exposure. NGF significantly induced skin and lung fibroblast migration in an in vitro model of wounded fibroblast and skin migration in Boyden chambers. Nevertheless NGF did not influence either skin or lung fibroblast proliferation, collagen production, or metalloproteinase production or activation. In contrast, culture of both lung and skin fibroblasts with NGF modulated their phenotype into myofibroblasts. Moreover, addition of NGF to both fibroblast types embedded in collagen gel increased their contraction. Fibrotic human lung or skin tissues displayed immunoreactivity for NGF, trkA, and p75. These data show a direct pro-fibrogenic effect of NGF on skin and lung fibroblasts and therefore indicate a role for NGF in tissue repair and fibrosis.

Nerve growth factor antibody exacerbates neuropathological signs of experimental allergic encephalomyelitis in adult lewis rats.

In this study, experimental allergic encephalomyelitis (EAE) rats and rats exhibiting EAE expressing high circulating anti-nerve growth factor antibody were daily monitored for clinical signs and chronic relapses. Eighty-five days after EAE induction, blood, spinal cord and brain stem were used for histological examination, nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) evaluation. The results showed that NGF-deprived rats display more severe clinical signs of disease. These effects were associated with a significant reduction of NGF in the brain stem and spinal cord but not of BDNF, which decreased only in spinal cord. These observations provide additional support to the hypothesis of a protective NGF role in rats exhibiting EAE.

Nerve growth factor promotes corneal healing: structural, biochemical, and molecular analyses of rat and human corneas.

PURPOSE: A recent clinical report demonstrated that topical nerve growth factor (NGF) treatment in patients affected by corneal neurotrophic ulcers induced epithelial and stromal healing restoring corneal integrity. Mechanisms(s) undergoing these clinical NGF actions are still unclear. The aim of this study was to investigate the role of NGF in human and rat cornea physiopathology. METHODS: Expression of high-affinity NGF receptors, NGF-mRNA, and NGF protein was evaluated in human and rat normal corneas, in human and rat corneal epithelial cell cultures, in human corneal organ culture, and in the rat cornea after an experimental model of epithelial injury, by means of immunohistochemistry, in situ hybridization reverse transcription-polymerase chain reaction, and enzyme-linked immunosorbent assay. RESULTS: The resultant data demonstrated that NGF is a constitutive molecule present and produced in normal human and rat corneas. In vitro human and rat corneal epithelial cells produce, store, and release NGF and also express high-affinity NGF receptors (TrkA). In human organ culture, epithelium, keratocytes, and endothelium have been shown to bind exogenous radiolabeled NGF, and the epithelial cells' binding was increased after epithelium injury. In vivo, after rat corneal epithelial injury, a transient increase of corneal NGF levels was observed. Inhibition of endogenous NGF activity by neutralizing anti-NGF antibodies delayed the corneal epithelial healing rate, whereas exogenous administration of NGF accelerated healing. CONCLUSIONS: Taken together, the above findings show that NGF plays an important role in corneal physiopathology and suggest that this neurotrophin may exert therapeutic action in wide-spectrum corneal diseases.

Nerve growth factor is an autocrine factor essential for the survival of macrophages infected with HIV.

Nerve growth factor (NGF) is a neurotrophin with the ability to exert specific effects on cells of the immune system. Human monocytes/macrophages (M/M) infected in vitro with HIV type 1 (HIV-1) are able to produce substantial levels of NGF that are associated with enhanced expression of the high-affinity NGF receptor (p140 trkA) on the M/M surface. Treatment of HIV-infected human M/M with anti-NGF Ab blocking the biological activity of NGF leads to a marked decrease of the expression of p140 trkA high-affinity receptor, a concomitant increased expression of p75(NTR) low-affinity receptor for NGF, and the occurrence of apoptotic death of M/M. Taken together, these findings suggest a role for NGF as an autocrine survival factor that rescues human M/M from the cytopathic effect caused by HIV infection.

Learning abilities, NGF and BDNF brain levels in two lines of TNF-alpha transgenic mice, one characterized by neurological disorders, the other phenotypically normal.

In this study we used two lines of transgenic mice overexpressing tumor necrosis factor alpha (TNF-alpha) in the central nervous system (CNS), one characterized by reactive gliosis, inflammatory demyelination and neurological deficits (Tg6074) the other showing no neurological or phenotypical alterations (TgK3) to investigate the effect of TNF-alpha on brain nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) levels and learning abilities. The results showed that the amount of NGF in the brain of Tg6074 and TgK3 transgenic mice is low in the hippocampus and in the spinal cord, increases in the hypothalamus of Tg6074 and showed no significant changes in the cortex. BDNF levels were low in the hippocampus and spinal cord of TgK3. BDNF increased in the hypothalamus of TgK3 and Tg6074 while in the cortex, BDNF increased only in Tg6074 mice. Transgenic mice also had memory impairments as revealed by the Morris Water Maze test. These findings indicate that TNF-alpha significantly influences BDNF and NGF synthesis, most probably in a dose-dependent manner. Learning abilities were also differently affected by overexpression of TNF-alpha, but were not associated with inflammatory activity. The possible functional implications of our findings are discussed.

Altered nerve growth factor level in the optic nerve of patients affected by multiple sclerosis.

In this study we measured with a highly sensitive two-site immunoenzymatic assay the levels of nerve growth factor (NGF) in human optic nerve affected by multiple sclerosis (MS). The result of this study showed an elevated increase of NGF in the MS optic nerves, as compared to the level of NGF found in the optic nerves non-affected by this demyelinating disorder. Moreover, the results showed that the optic nerves also expressed trkA NGF receptor and NGFmRNA, most likely by oligodendrocytes, implying that NGF is locally produced and suggesting that the presence of NGF might be regulated by an autocrine mechanism. These and other ongoing studies on animal models indicate that altered NGF levels are among one of the early symptoms of these demyelinating diseases. The physiopathological role of NGF in the optic nerve during demyelinating disorders remains however to be defined.