BACKGROUND OF THE INVENTION In the older population at any given time, there are neurons that, though still viable, are vulnerable to a variety of primary insults ranging from mechanical trauma to ischemia to genetic factors which can initiate disease onset. Apparently loss of trophic support and exitotoxin release may account for neuronal damage and eventual cell death by apoptosis.

The spread of this damage is perpetuated by secondary degeneration that allows directly injured neurons to release noxious and degenerative substances into the extracellular milieu.

As an example, also glaucoma is a progressive neurodegenerative disease of the optic nerve morphologically characterized by retinal ganglion cells (RGC) death resulting in functional visual deterioration. At present, treatment of glaucoma continues to be directed at lowering intraocular pressure to decrease the likelihood of disease progression. Interest has been increasing in preventing progression of glaucomatous optic nerve neuropathy using approaches based on the premise that glaucoma is a neurodegenerative disease.

Neuroprotective therapy has the potential to provide resilience to such neurons in an effort to prevent or delay progressive neuronal degeneration. Neuroprotection refers to any intervention, either external to the optic nerve or internally, that will lead to an intracellular change in the balance between survival and death signal in favour of survival.

Several neurotrophic factors have been reported to promote the survival of axotomized and naturally dying retinal neural cells. Among them, NGF and BDNF have been reported to exert a protective action on ocular hypertension and to promote recovery of damaged RGCs from various injuries, including optic nerve transection, ischemia and retinal degeneration.

In addition, NGF has been shown to be therapeutically useful for human corneal ulcer, whose deficit is one of the major cause of visual impairment in ocular surface pathology.

Similarly treatment with NGF in patients suffering from disorders induced by fifth palsy, postviral infections, diabetes, corneal surgery, neurotrophic keratitis and multiple sclerosis has been equally effective for restoring corneal integrity and sensitivity.

The effect of nicergoline on the retinal function in association with beta-blockers and the evaluation of its efficacy on blood flow in glaucoma patients was studied by Parisi et al., Pharmacological Research, Vol. 40, No. 3, 1999, pages 249-255 and by R. Protti et al., Acta Ophtalmol. Scan. Suppl. 76 (277) : 42-45, 1988 respectively. The former article shows that this drug is not a specific treatment of glaucoma and the latter one deals with the ocular region perfusion improvement due to the vaso-active action of nicergoline, which acts as a- 1 antagonist drug.

SUMMARY OF THE INVENTION It has been found that oral treatment with nicergoline or its metabolites MDL and MMDL is effective in restoring the age-related decline of trophic factors NGF and BDNF in optical nerve. Therefore, it is a first object of the present invention the use of nicergoline and its two metabolites MDL and MMDL in the treatment and/or prevention of ocular disorders, including glaucoma and neurodegenerative disease conditions of the retina and the optic nerve, associated with degeneration of the retinal ganglion cell layer and optic nerve due to the decline of trophic factors NGF and BDNF. In a further aspect, this invention provides the use of nicergoline or its metabolites MDL and MMDL in the manifacture of a medicament for the treatment and/or prevention of ocular disorders as defined above.

DETAILED DESCRIPTION OF THE INVENTION The evidence that repeated oral administration of nicergoline specifically stimulates the endogenous production of NGF and BDNF in the optic nerve of aged rodents, suggests the possibility of using similar strategy for preventing and/or treating human optic nerve neuropathies.

The two metabolites of nicergoline (commercially available (8p)-10-methoxy-1, 6- dimethylergoline-8-methanol-5-bromo-3-pyridinecarboxylate, SERMION (g)) are 10- methoxy-dihydrolysergol (MDL) and 1-methyl-10-methoxy-dihydrolysergol (MMDL), described for example in Bani et al., Proceedings of the IVInt. Symposiu771 on Advances in.

Alzheimer Therapy : 1996Apr l0-1d, Nice, 132. The present invention is related to the use of nicergoline, MDL or MMDL in the treatment and/or prevention of neurodegenerative disorders of the retina and the optic nerve associated with degeneration of the retinal ganglion cell layer and optic nerve due to the decline of trophic factors NGF and BDNF.

Such disorders include, but are not limited to atrophic macular degeneration, glaucoma, iatrogenic retinopathy, diabetic retinopathy, retinitis pigmentosa, and other optic neuropathies. Nicergoline, MDL or MMDL can be administered in effective dose with or without other therapeutic and adjuvant agents commonly used to treat, prevent or manage such disorders.

In a further aspect, this invention provides the use of nicergoline, MDL or MMDL with or without other therapeutic and adjuvant agents in the preparation of a medicament for the treatment and/or prevention of neurodegenerative disorders of the retina and the optic nerve associated with degeneration of the retinal ganglion cell layer and optic nerve due to the decline of trophic factors NGF and BDNF. A further aspect of the present invention is a method of treating ocular neuropaties characterized by ocular hypertension, corneal innervation damages and neurodegenerative disease conditions of the retina and the optic nerve due to the decline of trophic factors NGF and BDNF, which method comprises repeated administration of nicergoline, MDL or MMDL with or without other therapeutic and adjuvant agents to an individual in need of such treatment. The term repeated administration refers preferably to a daily administration once to several times.

Nicergoline, MDL or MMDL are preferably formulated into a variety of pharmaceutical compositions, including all forms of systemic and local delivery to the eye, such as orally; parenteral; subconjunctival injection or implants; intravitreal injection or implants.

Therefore, the medicament of the present invention include oral pharmaceutical composition, subconjunctival injection or implants ; intravitreal injection or implants.

According to the present invention, Nicergoline, MDL or MMDL is preferably prepared in a suitable pharmaceutically composition and formulated according to conventional technology and would include one or more excipients. For example, topically administrable compositions may contain tonically-adjusting agents, such as chlorobutanol, benzalkonium chloride, or chlorhexidine; buffering agents; and thickening agents.

Accordingly, the present invention provides the use of nicergoline, MMDL and MDL in the suitable pharmaceutical vehicles or dosage forms for injectable compositions, implants and systemic oral and parenteral compositions.

A preferred mode of administering compounds is the topical ocular administration and can be formulated into a variety of topically administrable ophthalmic compositions, such as solutions, suspensions, gels or ointments.

Doses intended for administration to human beings will typically contain Nicergoline, MDL or MMDL in an amount of from 60 to 120 mg, in particular in an amount of from 10 to 30 mg b. i. d. or t. i. d. for oral preparation, and from 0.5 to 5 mg/die for injections. In general, for topical administration an amount of Nicergoline, MDL or MMDL between about 0.001 and about 10.0 % by weight (wt %) is used in the compositions of the present invention. It is preferred that between about 0.01 and about 3.0 wt % is used, and it is especially preferred to use an amount between about 0.1 and about 2.0 wt %, with 1-2 drops once to several times a day.

Additional therapeutic agents may be added to supplement the compounds.

EXAMPLE 1 Male Sprague-Dawley albino rats 3, and 18 months old were obtained from Charles River Italia, Italy. The animals were housed under standard light/dark conditions (light on 7: 00, off 19: 00) with food pellets and water ad libitum. Animals were housed three/cage, as homogenous as possible in term of body weight. six rats from each age/treatment group were used for NGF and BDNF assay. Animal experiments were carried out according to the European Community Council Directives of 24 November 1986 (86/609/EEC) and approved by the Ethical Committee for Animal Experiment of Bologna University.

18 month old (aged) rats were studied in comparison with 3 month old (adult). Nicergoline was administered in aged rats in food pellets at the dosage of (lOmg/kg/day) for 120 days before killing.

Dose of nicergoline used and length of administration was chosen on the basis of previous studies by McArthur et al. (1997). In order to minimize variability of drug dosing regiment due to oral route in food pellets, the following precautions were taken. Animals were chosen homogeneous as body weight in each age groups. Food intake was measured in preliminary experiments in group of 3, and 18-months old rats (N=8 in each group) and in a small group (N=5) of 21-months old animals. According to literature, and according to Charles River reports, daily pellet intake is 25-30gr/animal. This was not modified in old rats, even in the presence of body weight gain.

Biochemical measurements For NGF and BDNF measurement rats were sacrificed by decapitation. Brains were dissected out according to standard techniques, optic nerves isolated and quickly frozen.

NGF levels were measured using a two site immunoenzymatic assay (EIA): polystyrene 96- well microtitle immunoplates were coated with affinity-purified polyclonal goat anti-NGF antibody. Parallel wells were coated with pre-immune goat IgG for evaluation of non- specific signal. After 5 hr at 20°C the plates were washed (as in subsequent steps) with PBS/0.05% Tween 20 and then incubated for 2hr at 20°C with PBS/0. 05% Tween 20 + 1% fetal calf serum to block non specific binding sites. After washing, NGF standard solutions, that ranged 0 to 1 ng/ml, were distributed into each plate. The samples were ultrasonicated at 4°C in the sample buffer and centrifuged at 9500g for 30 min. 100 ul of supernatant was added to each well and the plates were incubated overnight at 4°C. The plates were then washed and 1 00Al of monoclonal antibody against NGF, diluted 1: 100 in PBS, was added to each well. After incubation for 4hr at 20°C, the plates were washed and incubated with biotinylated rat immunoglobulins (1: 800, Zymed, South San Francisco, USA). The subsequent incubation with peroxidase-conjugated streptavidin (Zymed) and addition of o- phenyldiamine resulted in a colourimetric reaction whose optical density was measured at 490nm using a Dynatech ME5000 microplate reader. Specificity for NGF was also assessed by using recombinant human BDNF (Genentech, USA). The procedure is described per <BR> <BR> extenso elsewhere (Bracci-Laudiero et al. , 1992). The concentrations of BDNF were measured using an enzyme-linked immunosorbent assay kit"BDNF Emaxtm ImmunoAssay System number G6891"by Promega (Madison, WI, USA) following the instructions suggested by the manufacturer.

Statistical analysis In the descriptive analysis data were expressed as mean+SEM. Statistical analysis was carried out using the one way analysis of variance (ANOVA) and Dunnett's test to compare the different experimental groups; Student's t test (GraphPad PRISM software package Macintosh, San Diego, CA, USA) was also used when appropriate Probability was set at 5% level (2-tailed).

RESULTS Aging effects in the optic nerve are generally manifested as a severe decline in neurotrophins content. Table I shows the effect of aging and nicergoline treatment on NGF and BDNF content in the rat optic nerve. Levels of NGF and BDNF were decreased by 66% and 52% respectively in the optic nerve of aged (18 months) rats compared with adults (3 months). Long term treatment with nicergoline (10 mg/kg, p. o. for 3 months) significantly counteracted the age-related decrease of NGF and BDNF content in the rat optic nerve suggesting that nicergoline and its two metabolites MMDL and MDL are able to increase the endogenous production of neurotrophins. In particular nicergoline was effective not only in preventing NGF and BDNF decline observed in aged rats, but also in fully restoring BDNF levels to the value of young animals.

Table I-NGF AND BDNF CONTENT IN RAT OPTIC NERVE: EFFECT OF AGING AND NICERGOLINE TREATMENT. Neurotrophin (pg/ml) Adult (3 months, Aged (18 months, Aged (18 months, untreated) untreated) treated) NGF 213. 8 34. 2 73. 2 18. 7 ** 148. 5 53. 5 BDNF 1396. 6 293. 6 671. 0 179. 1 ** 1668. 0 346. 0 # Values are means A standard error for 5 or 6 rats.

Statistical analysis; : ANOVA and Dunnet test for age effect, Student's"t"test for treatment effect in aged-matching groups.

** P < 0.01 vs. adult; # P < 0.05 vs. aged untreated.