The pleiotropic molecule NGF regulates the in vitro properties of fibroblasts, keratinocytes, and endothelial cells: implications for wound healing

Nerve growth factor (NGF) is recognized as a pleiotropic molecule, exerting a variety of biological effects on different cell types and pathophysiological conditions, and its role in tissue wound healing has been recently highlighted. However, the preferential cellular target of NGF is still elusive in the complex cellular and molecular cross talk that accompanies wound healing. Thus, to explore possible NGF cellular targets in skin wound healing, we investigated the in vitro NGF responsiveness of keratinocytes (cell line HEKa), fibroblasts (cell line BJ), and endothelial cells (cell line HUVEC), also in the presence of adverse microenvironmental conditions, e.g., hyperglycemia. The main results are summarized as follows: 1) NGF stimulates keratinocyte proliferation and HUVEC proliferation and angiogenesis in a dose-dependent manner although it has no effect on fibroblast proliferation; 2) NGF stimulates keratinocyte but not fibroblast migration in the wound healing assay; and 3) NGF completely reverts the proliferation impairment of keratinocytes and the angiogenesis impairment of HUVECs induced by high d-glucose concentration in the culture medium. These results contribute to better understanding possible targets for the therapeutic use of NGF in skin repair.

Endogenous nerve growth factor stimulation: effects on auditory pathway neural cells in a mouse model

OBJECTIVE

In the present study, we investigated whether high-pressure hypotonic saline solution (Hphss) affects the basal level of Nerve Growth Factor (NGF) and expression of receptors in the cochlea, bark earing, retina, and visual cortex.

MATERIALS AND METHODS

For this study, we used three weeks old female Sprague Dawley (SD) rats (n = 12). Rats were housed in polypropylene cages and were kept under standard conditions (12 h light:12 h dark cycle) with free access to water and food (Purina chow food). A specific dispenser was employed to deliver sterile hypotonic saline at high pressure (pressing emission level (PEL): 7 g/s; emission time (ET): 0.5 s). Rats were divided into two groups: untreated (n = 6) and treated with Hphss (n = 6), three times per day, for 10 consecutive days. Treatment was performed in both nostrils with 50 µl of Hphss using a microsyringe equipped with a plastic tip.

RESULTS

We observed a significant enhancement in the level of NGF in the cochlea and bark earing, but not in the retina and visual cortex. This is likely because the nasolacrimal duct pathway does not appear to have an effect on the retina, and the visual cortex appears to be too far from the cribriform plate to be reached by nasal NGF.

CONCLUSIONS

This treatment can significantly protect and/or delay degeneration of cochlear auditory NGF-target cells. It is free from side effects and can be used in chronic diseases for as long as needed. It remains to be investigated whether the effects of short-term therapy are long-lasting, or if the treatment must be repeated.

Nasal HPpSIS administration enhances NGF and tumor suppressor protein, p73 in human brain cancer tissues: preliminary data

OBJECTIVE

Nerve Growth Factor (NGF) is a neurotrophic factor known to play a critical role in growth, survival, differentiation and neuroprotection of peripheral sensory and sympathetic neurons, as well as brain neurons. We have recently reported that nasal administration of high-pressure isotonic physiological saline solution (HPpSIS) enhances the level of NGF and the expression of NGF receptors in neurons of the olfactory bulbs and forebrain cholinergic neurons of laboratory animals. In the present study, we sought to determine whether the same treatment affects the levels of NGF within the brain tumor tissue.

PATIENTS AND METHODS

This study was conducted on eight adult patients, 4 males and 4 females with malignant anterior cranial fossa tumor. Before surgery, four subjects, two males and two females received nasal administration of HPpSIS for ten consecutive days.

RESULTS

The levels of NGF in surgical removed peripheral tumor brain samples of patients treated with nasal HPpSIS administration are more elevated compared to the levels of NGF in peripheral brain tissues of HPpSIS untreated patients.

CONCLUSIONS

We observed that nasal administration of HPpSIS enhances not only the basal brain NGF levels and the expression of NGF receptors but also the tumor suppressor protein p73. The possible functional significance of these observations will be described and discussed.

High-pressure physiological saline isotonic solution administration enhances brain NGF and NGF-receptors expression

OBJECTIVE

Nerve growth factor (NGF) is a neurotrophin which promotes and regulates the survival of neurons in the peripheral nervous system. The aim of this study was to investigate the effect of high-pressure administration of sterile physiological saline isotonic solution (HpPSIS) into nasal cavity of laboratory animals on NGF levels and NGF-receptor expression in the olfactory bulbs and brain.

MATERIALS AND METHODS

For this study we used three weeks old female Sprague Dawley SD rats (n=48). Rats were divided into two groups, the first one treated delivering physiological saline solution with a normal syringe modified at the extremity to fit the rats' nostril (5 ml) (n=24) and the second one treated spray with HpPSIS (n=24 rats). Rats were treated three times a day either for 5 consecutive days (shorth term treatment) or 10 consecutive days (longer treatment) in both nostrils of HpPSIS delivered at high pressure (pression emission level: PEL: 7 g/sec for emission time ET: 0.5 sec) with a specific forced spray erogator. Untreated rats received a similar manipulation three times a day through a syringe in the nostrils, but no HpPSIS administration.

RESULTS

The results of these studies highlight the possibility that endogenous enhancement of NGF by stimulation of NGF-producing cells within the nasal cavities and also in the CNS represent a novel experimental approach to enhance the brain NGF levels with a new therapy. HpPSIS treatment further enhances the presence of NGF in the four brains examined. Indeed, a significant increase of NGF was first observed after 5 days of HpPSIS treatment, compared to HpPSIS untreated rats. The increase was over 25% in the OB, ST, HI and in CX, while 10 days after HpPSIS treatments the levels of NGF were even higher. These differences were statistically significant, p < 0.05.

CONCLUSIONS

It was found that forced administration of HpPSIS enhances the presence of these neurotrophic signals, not only in the olfactory bulbs, but also in forebrain cholinergic neurons, which are known to degenerate as result of memory loss and brain aging, including Alzheimer Disease. These findings for the first time in the literature demonstrate the possibility of enhancing the endogenous NGF to protect NGF-damaged neurons. Since the enhanced expression of NGF was first observed after 5 days of treatment and higher after 10 days of treatment, a reasonable hypothesis is that longer HpPSIS treatment might further enhance the level of NGF in brain and olfactory bulbs.

Enhanced presence of NGF and mast cells number in nasal cavity after autologous stimulation: relation with sensorineural hearing deficit

OBJECTIVE

Nerve growth factor (NGF) is a neurotrophin which promote and regulate the survival of neurons in the peripheral nervous system. We aimed to evaluate the nasal NGF expressions of mast cells in healthy patients after stimulation with sterilized isotonic solution delivered at high pressure.

PATIENTS AND METHODS

The first part of the study was made with 21 voluntary individuals. The middle third of the inferior turbinate epithelial cells on the right nostril was scraped using a sterile curette and indicated as (pre), than a spray of sterilized isotonic solution at high pressure on the left nostril was delivered and 25 minutes later a similar stimulation was delivered on the same nostril. The stimulation was made with a specific spray. The middle third of the inferior turbinate epithelial cells on the left nostril was scraped using a sterile curette and indicated as (post).

RESULTS

Forced nasal stress induced by local delivery of high pressure physiological solution causes an increase in the number of mast cells and enhances level of NGF in the nasal fluid compared to the control subjects. So based on the first part of our study, since NGF is universally known as effective in protection and repairing of neural cells damage, we started the second part and gave a treatment on the same patients, to increase NGF levels with a six months daily therapy and observed the variations in Sensorineural Hearing Loss (SNHL) and tinnitus intensity from the beginning to the end of the therapy. All patients received sterilized isotonic solution at high pressure (pression emission level: PEL): 7 g/sec for 0.5 sec (emission time: ET) in both nostrils. 25 minutes later a similar stimulation was delivered twice a day. The control group (21 pts) received normal therapy with betahistine dihydrochloride 16 mg twice a day.

CONCLUSIONS

Upon acuphenometry, there was a lower intensity of tinnitus and the improvement was signaled by the patients. Patients with SNHL treated with conventional therapy had a slight worsening, while the patients treated with our new therapy which increased NGF levels, showed improvement of hearing. This new therapy represents a new therapy of SNHL, tinnitus and hearing disorders.

Electroacupucture and nerve growth factor: potential clinical applications

The nerve growth factor (NGF) is a neurotrophin regulating the survival and function peripheral sensory and sympathetic neurons and of forebrain cholinergic neurons. Both peripheral neuropathies and brain cholinergic dysfunctions could benefit from NGFbased therapies, but the clinical use of NGF has been so far hampered by the development of important side effects, like hyperalgesia and autonomic dysfunctions. Acupuncture is a therapeutic technique and is a part of traditional Chinese medicine. Western descriptions of the clinical efficacy of acupuncture on pain, inflammation, motor dysfunction, mood disorders, and seizures are based on the stimulation of several classes of sensory afferent fibers and the consequent activation of physiological processes similar to those resulting from physical exercise or deep massage. Recently, it has been shown that peripheral sensory stimulation by electroacupuncture (EA) could improve brain NGF availability and utilization, at the same time counteracting the major sideeffects induced by NGF administration. This review focuses on the emerging links between EA and NGF with special emphasis on the work carried out in the last decade in our laboratory, investigating the role of NGF as a mediator of EA effects in the central nervous system and as a modulator of sensory and autonomic activity.