Intranasal deferoxamine improves performance in radial arm water maze, stabilizes HIF-1α, and phosphorylates GSK3ß in P301L tau transgenic mice.

Deferoxamine (DFO), a metal chelator, has been previously reported to slow the loss of spatial memory in a mouse model of amyloid accumulation when delivered intranasally (IN). In this study, we determined whether IN DFO also has beneficial effects in the P301L mouse, which accumulates hyperphosphorylated tau. Mice were intranasally treated three times per week with either 10% DFO (2.4 mg) or saline for 5 months, and a battery of behavioral tests were conducted before tissue collection and biochemical analyses of brain tissue with Western blot and ELISA. Wild-type (WT) mice statistically outperformed transgenic (TG) saline mice in the radial arm water maze, while performance of TG-DFO mice was not different than WT mice, suggesting improved performance in the radial arm water maze. Other behavioral changes were not evident. Beneficial changes in brain biochemistry were evident in DFO-treated mice for several proteins. The TG mice had significantly less pGSK3ß and HIF-1α, with more interleukin-1ß and total protein oxidation than wild-type controls, and for each protein, DFO treatment significantly reduced these differences. There was not a significant decrease in phosphorylated tau in brain tissue of DFO-treated mice at the sites we measured. These data suggest that IN DFO is a potential treatment not only for Alzheimer's disease, but also for other neurodegenerative diseases and psychiatric disorders in which GSK3ß and HIF-1α play a prominent role.

Delivery of interferon-beta to the monkey nervous system following intranasal administration.

We determined the nervous system targeting of interferon-beta1b (IFN-beta1b), a 20 kDa protein used to treat the relapsing-remitting form of multiple sclerosis, following intranasal administration in anesthetized, adult cynomolgus monkeys. Five animals received an intranasal bolus of [(125)I]-labeled IFN-beta1b, applied bilaterally to the upper nasal passages. Serial blood samples were collected for 45 min, after which the animals were euthanized by transcardial perfusion-fixation. High resolution phosphor imaging of tissue sections and gamma counting of microdissected tissue were used to obtain the distribution and concentration profiles of [(125)I]-IFN-beta1b in central and peripheral tissues. Intranasal administration resulted in rapid, widespread targeting of nervous tissue. The olfactory bulbs and trigeminal nerve exhibited [(125)I]-IFN-beta1b levels significantly greater than in peripheral organs and at least one order of magnitude higher than any other nervous tissue area sampled. The basal ganglia exhibited highest [(125)I]-IFN-beta1b levels among CNS regions other than the olfactory bulbs. Preferential IFN-beta1b distribution to the primate basal ganglia is a new finding of possible clinical importance. Our study suggests both IFN-beta and IFN-alpha, which share the same receptor, may be bound with relatively high affinity in these structures, possibly offering new insight into a neurovegetative syndrome induced by IFN-alpha therapy and suspected to involve altered dopamine neurotransmission in the basal ganglia. Most importantly, our results suggest intranasally applied macromolecules may bypass the blood-brain barrier and rapidly enter the primate CNS along olfactory- and trigeminal-associated extracellular pathways, as shown previously in the rat. This is the first study to finely detail the central distribution of a labeled protein after intranasal administration in non-human primates.

Intranasal delivery of insulin and a nitric oxide synthase inhibitor in an experimental model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder in which motor neurons may be targeted by oxidative and nitrergic stress without sufficient compensation by intrinsic support mechanisms. In this work, we addressed two key tenets of this hypothesis for the pathogenesis of ALS. Using superoxide dismutase (SOD) 1G93A mice, we studied the impact of reduction of nitrergic stress within the CNS with the use of a broad spectrum nitric oxide synthase (NOS) inhibitor, NG-nitro-l-arginine methyl ester. A separate cohort of SOD1G93A mice received direct insulin neurotrophic support, ligating receptors expressed upon motor neurons, to attempt protection against neuronal and functional motor dropout. For direct access, we used a novel form of intranasal delivery that provides peak concentration levels in the CNS within 1 h of delivery without systemic side effects at doses which previously rescued retrograde loss of motor axons after axotomy. To identify even minor impacts of these interventions on the outcome, we utilized an intensive program of serial behavioral and electrophysiological testing weekly, combined with endpoint quantitative morphometry and molecular analysis. This intensive evaluation enhanced our knowledge of the time course in SOD1G93A mice and impact of the SOD1G93A mutation upon motor neurons and their function. Neither intervention had even minimal impact upon slowing progression of disease in SOD1G93A mice. Our data argue against significant roles for nitrergic stress in promoting motor neuron loss and the importance of alternative neurotrophic support mechanisms that might support motor neurons and prevent disease progression in SOD1G93A mice.

Characterization of the AD7C-NTP cDNA expression in Alzheimer's disease and measurement of a 41-kD protein in cerebrospinal fluid.

We have isolated a novel Alu sequence-containing cDNA, designated AD7c-NTP, that is expressed in neurons, and overexpressed in brains with Alzheimer's disease (AD). The 1,442-nucleotide AD7c-NTP cDNA encodes an approximately 41-kD protein. Expression of AD7c-NTP was confirmed by nucleic acid sequencing of reverse transcriptase PCR products isolated from brain. AD7c-NTP cDNA probes hybridized with 1. 4 kB mRNA transcripts by Northern blot analysis, and monoclonal antibodies generated with the recombinant protein were immunoreactive with approximately 41-45-kD and approximately 18-21-kD molecules by Western blot analysis. In situ hybridization and immunostaining studies localized AD7c-NTP gene expression in neurons. Using a quantitative enzyme-linked sandwich immunoassay (Ghanbari, K., I. Beheshti, and H. Ghanbari, manuscript submitted for publication) constructed with antibodies to the recombinant protein, AD7c-NTP levels were measured under code in 323 clinical and postmortem cerebrospinal fluid (CSF) samples from AD, age-matched control, Parkinson's disease, and neurological disease control patients. The molecular mass of the AD7c-NTP detected in CSF was approximately 41 kD. In postmortem CSF, the mean concentration of AD7c-NTP in cases of definite AD (9.2+/-8.2 ng/ml) was higher than in the aged control group (1.6+/-0.9; P < 0.0001). In CSF samples from individuals with early possible or probable AD, the mean concentration of AD7c-NTP (4.6+/-3.4) was also elevated relative to the levels in CSF from age-matched (1.2+/-0.7) and neurological disease (1.0+/-0.9) controls, and ambulatory patients with Parkinson's disease (1.8+/-1.1) (all P < 0.001). CSF levels of AD7c-NTP were correlated with Blessed dementia scale scores (r = 0. 66; P = 0.0001) rather than age (r = -0.06; P > 0.1). In vitro studies demonstrated that overexpression of AD7c-NTP in transfected neuronal cells promotes neuritic sprouting and cell death, the two principal neuroanatomical lesions correlated with dementia in AD. The results suggest that abnormal AD7c-NTP expression is associated with AD neurodegeneration, and during the early stages of disease, CSF levels correlate with the severity of dementia.

Intranasal deferoxamine affects memory loss, oxidation, and the insulin pathway in the streptozotocin rat model of Alzheimer's disease.

Accumulation of metal and the accompanying increase in oxidative stress and inflammation plays an important role in neurodegenerative disease. Deferoxamine (DFO) is a metal chelator found to be beneficial in several animal models of neurodegenerative disease and insult including Alzheimer's disease, Parkinson's disease, stroke, and subarachnoid hemorrhage. In this study, we determine whether intranasally (IN) administered DFO is beneficial in the intracerebroventricular streptozotocin (ICV STZ) rat model of sporadic Alzheimer's disease, which is different from previous models in that it exhibits dysregulation of insulin metabolism as well as oxidative stress and inflammation. Surgical induction of the model included ICV injections of either STZ or citrate buffer (sham in rats), which were treated IN with either saline or DFO (n=10-15/group). Treatment started either before or after injection of STZ to induce the model, and continued throughout the study. IN treatment continued three times per week for three weeks before behavior tests started followed by eventual euthanasia with tissue collection. Spatial memory tests with the Morris water maze showed that STZ rats treated with IN DFO both before and after model induction had significantly shorter escape latencies. Pre-treatment with IN DFO also significantly decreased footslips on the tapered balance beam test. Brain tissue analyses showed DFO treatment decreased oxidation as measured by oxyblot and increased insulin receptor expression. These results further support the potential of IN DFO for use as a treatment for Alzheimer's disease, and show benefit in a non-amyloid/tau rodent model.

Effects of intranasal insulin on cognition in memory-impaired older adults: modulation by APOE genotype.

Raising insulin acutely in the periphery and in brain improves verbal memory. Intranasal insulin administration, which raises insulin acutely in the CNS without raising plasma insulin levels, provides an opportunity to determine whether these effects are mediated by central insulin or peripheral processes. Based on prior research with intravenous insulin, we predicted that the treatment response would differ between subjects with (epsilon4+) and without (epsilon4-) the APOE-epsilon4 allele. On separate mornings, 26 memory-impaired subjects (13 with early Alzheimer's disease and 13 with amnestic mild cognitive impairment) and 35 normal controls each underwent three intranasal treatment conditions consisting of saline (placebo) or insulin (20 or 40 IU). Cognition was tested 15 min post-treatment, and blood was acquired at baseline and 45 min after treatment. Intranasal insulin treatment did not change plasma insulin or glucose levels. Insulin treatment facilitated recall on two measures of verbal memory in memory-impaired epsilon4- adults. These effects were stronger for memory-impaired epsilon4- subjects than for memory-impaired epsilon4+ subjects and normal adults. Unexpectedly, memory-impaired epsilon4+ subjects showed poorer recall following insulin administration on one test of memory. These findings suggest that intranasal insulin administration may have therapeutic benefit without the risk of peripheral hypoglycemia and provide further evidence for apolipoprotein E (APOE) related differences in insulin metabolism.

Stimulation of guanylate cyclase by EDTA and other chelating agents.

The partially purified soluble guanylate cyclase (GTP pyrophosphatelyase(cyclizing), EC 4.6.1.2) from human caudate nucleus is stimulated from 2 to 4-fold by metal chelating agents. EDTA (K 1/2 - 4.8 microM) is more potent than CDTA (K 1/2 = 13.2 microM) or EGTA (K 1/2 = 21.8 microM) at stimulating activity. Stimulation by chelating agents is apparently not due to removal of inhibitory divalent cations which contaminate the enzyme or reaction mixture. EDTA increases guanylate cyclase activity in part by increasing the affinity of the enzyme for the substrate (MgGTP) 10-fold. Dopamine inhibits partially purified guanylate cyclase in the presence or absence of EDTA. Dopamine increases the Ka of guanylate cyclase for the activator, free Mn2+, more than 50-fold, from 3 to 150 microM.

A comparison of peripheral and central human muscarinic cholinergic receptor affinities for psychotropic drugs.

A peripheral model offers a valuable research tool for the investigation of central cholinopathic disorders. The in vitro affinities of several psychotropic drugs for the muscarinic cholinergic binding sites of human caudate and erythrocyte were compared in competition with a tritiated antagonist (quinuclidinyl benzilate). The relative affinities of the drugs for both tissues were strikingly similar. Thus, the erythrocyte muscarinic receptor may represent an accessible in vitro assay for the characterization of central cholinopathic states.

GM-1 treatment of Alzheimer's disease. A pilot study of safety and efficacy.

A double-blind, placebo-controlled pilot study was conducted to evaluate the safety and efficacy of treatment of patients with Alzheimer's disease using monosialoganglioside GM-1, a neurotrophic factor. Of 46 patients enrolled, 42 completed all study requirements. Nineteen patients received 100 mg of GM-1 by daily intramuscular injection for 12 weeks. Twenty-three patients received placebo. Case evaluations were done at baseline, week 12, and week 24 and included both cognitive and psychosocial scales. Study results suggested that the treatment was safe, yet offered no overall symptomatic benefit to patients with mild-to-moderate Alzheimer's disease. Whether or not GM-1 therapy may offer protective benefit by slowing or arresting the progression of the disease remains unclear, since the results of the cognitive evaluations suggested that neither the GM-1 group nor the placebo group declined significantly during the 24-week study.

Ganglioside monoclonal antibody (A2B5) labels Alzheimer's neurofibrillary tangles.

Ganglioside monoclonal antibody (A2B5) labels Alzheimer's neurofibrillary tangles both in isolated neurofibrillary tangle-bearing nerve cells and in partially purified preparations of tangle fibers. Antibody staining was preabsorbed by preincubation of antibody with neuronal ganglioside preparations. These results suggest that Alzheimer's neurofibrillary tangles have a ganglioside associated with them.

Pick's disease versus Alzheimer's disease: a comparison of clinical characteristics.

The clinical recognition of Pick's disease depends on its differentiation from Alzheimer's disease (AD). To identify distinguishing clinical features, we reviewed the clinical records of 21 patients with pathologically confirmed Pick's disease and matched them by sex, age of onset, and duration of dementia with 42 patients having pathologically confirmed AD. In the absence of temporal or frontal lobar atrophy on CTs, all the Pick patients and none of the AD patients had three of five clinical features: presenile onset (before age 65), an initial personality change, hyperorality, disinhibition, and roaming behavior. In addition, the Pick patients had a tendency toward reiterative and other speech disturbances. These findings suggest that Pick patients are potentially distinguishable from AD patients on the basis of clinical manifestations.

Pure hippocampal sclerosis: a rare cause of dementia mimicking Alzheimer's disease.

OBJECTIVES: To identify patients with pure hippocampal sclerosis (HS) as a cause of dementia, to determine whether they have had histories of hypotension or hypoxia, and to compare the clinical features of patients with pure HS with a control group of AD patients without HS. METHODS: In a retrospective study, the authors reviewed all 1771 cases received in their dementia brain bank from 1978 through 1996 to identify those patients with pure HS, defined as severe degeneration and gliosis of the CA1 sector and subiculum of the hippocampal formation in the absence of other significant dementing disease such as Alzheimer's changes. The control group included all patients received during the same period with severe AD without HS, infarcts, or other dementing disease. RESULTS: Seven pure HS cases (0.4%) were identified. None had any episodes of syncope, hypotension, or hypoxia reported in association with dementia onset. Six had memory loss as the primary presenting symptom, and all became progressively demented. Forty-five AD patients without HS were identified for the control group. There were no clear clinical differences between the two groups with regard to sex, age at onset, risk factors for vascular disease, symptoms of cerebrovascular disease, treatment with tranquilizing medications, treatment for depression, or nursing home placement. There was a tendency for heart disease to be more prevalent and the duration of illness to be shorter in the patients with pure HS. CONCLUSIONS: Pure hippocampal sclerosis (HS) occurred in only 0.4% of our dementia patients. Clinically, the seven patients with pure HS were similar to our AD control group. Further research is needed to determine the causes of HS and why HS appears to mimic AD.

Dementia lacking distinctive histologic features: a common non-Alzheimer degenerative dementia.

From a series of 460 dementia patients referred to a regional brain bank, 14 (3%) patients had a pathologic diagnosis of primary degeneration of the brain involving multiple sites (frontoparietal cortex, striatum, medial thalamus, substantia nigra, and hypoglossal nucleus), with cell loss and astrocytosis. There were no neuronal inclusions and essentially no senile plaques. This entity, which we have termed "dementia lacking distinctive histology" (DLDH), presented with memory loss and personality changes, and led to death, usually within 2 to 7 years. Dysarthria and dysphagia were prominent in the later phases of the illness in most patients. The psychometric findings of some of the patients were consistent with a "frontal" lobe dementia. A few patients had prominent caudate atrophy on CT as well as neuropathologically. Eight of our patients had positive family histories for neurologic disease, mainly dementia. DLDH, in addition to Pick's disease, is a major member of the frontal-lobe dementia group. In patients under age 70 years, the frontal lobe dementias represent an important diagnostic consideration.

Risk factors in Alzheimer's disease: a clinicopathologic study.

We investigated potential risk factors for Alzheimer's disease (AD) in a clinicopathologic study of 407 patients with definite AD, 100 non-Alzheimer dementia patients, and 50 normal subjects. The AD patients had more first-degree relatives with dementia than the non-AD dementia group (odds ratio of 1.85, 95% confidence interval of 1.07-3.20) or the normal elderly (odds ratio of 3.60, 95% confidence interval of 1.50-8.64) but did not have significantly more head injuries, medical and psychiatric illnesses, or relatives with Down's syndrome. The AD patients with a family history of dementia had their dementia at a later age than those without an affected relative. These findings indicate a familial risk for AD that is greater than for other dementing illnesses and has age-related penetrance. This study does not support other putative risk factors for AD such as head trauma and familial Down's syndrome.

Silica-ELISA method improves detection and quantitation of minor glycolipid components in lipid mixtures and of other antigens.

This paper describes a new type of ELISA plate in which the reaction wells have been coated with silica gel. ELISA using these prototype silica-ELISA plates is markedly more sensitive for glycolipid antigens in lipid mixtures than ELISA using polystyrene plates without silica. Silica-ELISA plates also improve the analysis of certain protein and carbohydrate antigens. This technology may be of considerable benefit in the analysis of minor lipids and other antigens from human brain, cerebrospinal fluid or blood.

Two cases of acute anti-GM1 antibody elevations in response to exogenous GM1 without neurological symptoms.

During a study evaluating GM1 ganglioside as a possible treatment for Alzheimer's disease, two patients suffered immune responses that appeared to be limited to localized inflammation at the sites of the intramuscular GM1 injections. We determined that one patient's anti-GM1 IgM antibody titer rose from 1:400 to 1:3200 and her anti-GM1 IgG titer from < 1:50 to 1:400,000 during the immune response. The second patient's titer rose from < 1:50 to 1:3200 IgM and from 1:3200 to 1:400,000 IgG. These findings document that patients may experience acute rises in their anti-GM1 antibody levels in response to GM1 and that such rises may not necessarily cause significant acute clinical neuronal injury.

Intranasal administration of interferon beta bypasses the blood-brain barrier to target the central nervous system and cervical lymph nodes: a non-invasive treatment strategy for multiple sclerosis.

Intranasal (i.n.) administration of IFN beta-1b was examined as a route for targeted delivery to the rat central nervous system (CNS). Intranasal administration resulted in significant delivery throughout the CNS and cervical lymph nodes with low delivery to peripheral organs. At similar blood levels, intravenous (i.v.) administration of IFN beta-1b yielded 88-98% lower CNS levels and 100-1650% greater peripheral organ levels compared to intranasal. Autoradiography confirmed much greater delivery to the CNS with intranasal administration. Intranasally administered IFN beta-1b reached the brain intact and produced tyrosine phosphorylation of IFN receptor in the CNS. Intranasal administration offers a non-invasive method of drug delivery for multiple sclerosis (MS) that bypasses the blood-brain barrier (BBB) and directly targets the CNS and lymph nodes.

Delivery of insulin-like growth factor-I to the rat brain and spinal cord along olfactory and trigeminal pathways following intranasal administration.

We investigated the CNS delivery of insulin-like growth factor-I (IGF-I), a 7.65 kDa protein neurotrophic factor, following intranasal administration and the possible pathways and mechanisms underlying transport from the nasal passages to the CNS. Anesthetized adult male Sprague-Dawley rats were given [125I]-IGF-I intranasally or intravenously and then killed by perfusion-fixation within 30 min. Other animals were killed following cisternal puncture and withdrawal of cerebrospinal fluid (CSF) or intranasal administration of unlabeled IGF-I or vehicle. Both gamma counting of microdissected tissue and high resolution phosphor imaging of tissue sections showed that the tissue concentrations and distribution following intranasal administration were consistent with two routes of rapid entry into the CNS: one associated with the peripheral olfactory system connecting the nasal passages with the olfactory bulbs and rostral brain regions (e.g. anterior olfactory nucleus and frontal cortex) and the other associated with the peripheral trigeminal system connecting the nasal passages with brainstem and spinal cord regions. Intranasal administration of [125I]-IGF-I also targeted the deep cervical lymph nodes, consistent with their possible role in lymphatic drainage of both the nasal passages and the CNS. Cisternal CSF did not contain [125I]-IGF-I following intranasal administration. Intravenous [125I]-IGF-I resulted in blood and peripheral tissue exposure similar to that seen following intranasal administration but CNS concentrations were significantly lower. Finally, delivery of IGF-I into the CNS activated IGF-I signaling pathways, confirming some portion of the IGF-I that reached CNS target sites was functionally intact. The results suggest intranasally delivered IGF-I can bypass the blood-brain barrier via olfactory- and trigeminal-associated extracellular pathways to rapidly elicit biological effects at multiple sites within the brain and spinal cord.

Delivery of neurotrophic factors to the central nervous system: pharmacokinetic considerations.

Neurotrophic factors are proteins with considerable potential in the treatment of central nervous system (CNS) diseases and traumatic injuries. However, a significant challenge to their clinical use is the difficulty associated with delivering these proteins to the CNS. Neurotrophic factors are hydrophilic, typically basic, monomeric or dimeric proteins, mostly in the size range of 5 to 30 kDa. Neurotrophic factors potently support the development, growth and survival of neurons, eliciting biological effects at concentrations in the nanomolar to femtomolar range. They are not orally bioavailable and the blood-brain and blood-cerebrospinal fluid barriers severely limit their ability to enter into and act on sites in the CNS following parenteral systemic routes of administration. Most neurotrophic factors have short in vivo half-lives and poor pharmacokinetic profiles. Their access to the CNS is restricted by rapid enzymatic inactivation, multiple clearance processes, potential immunogenicity and sequestration by binding proteins and other components of the blood and peripheral tissues. The development of targeted drug delivery strategies for neurotrophic factors will probably determine their clinical effectiveness for CNS conditions. Achieving significant CNS target site concentrations while limiting systemic exposure and distribution to peripheral sites of action will lessen unwanted pleiotropic effects and toxicity. Local introduction of neurotrophic factors into the CNS intraparenchymally by direct injection/infusion or by implantation of delivery vectors such as polymer matrices or genetically modified cells yields the highest degree of targeting, but is limited by diffusion restrictions and invasiveness. Delivery of neurotrophic factors into the cerebrospinal fluid (CSF) following intracerebroventricular or intrathecal administration is less invasive and allows access to a much wider area of the CNS through CSF circulation pathways. However, diffusional and cellular barriers to penetration into surrounding CNS tissue and significant clearance of CSF into the venous and lymphatic circulation are also limiting. Unconventional delivery strategies such as intranasal administration may offer some degree of CNS targeting with minimal invasiveness. This review presents a summary of the neurotrophic factors and their indications for CNS disorders, their physicochemical characteristics and the different approaches that have been attempted or suggested for their delivery to the CNS. Future directions for further research such as the potential for CNS disease treatment utilising combinations of neurotrophic factors, displacement strategies, small molecule mimetics, chimaeric molecules and gene therapy are also discussed.

Anandamides inhibit binding to the muscarinic acetylcholine receptor.

Loss of memory and cholinergic transmission are associated with both Alzheimer's disease (AD) and marijuana use. The human brain muscarinic acetylcholine receptor (mAChR), which is involved in memory function and is inhibited by arachidonic acid, is also inhibited by anandamides. Two agonists of the cannabinoid receptor derived from arachidonic acid, anandamide (AEA) and R-methanandamide, inhibit ligand binding to the mAChR. Binding of the mAChR antagonist [3H]quinuclidinyl benzilate ([3H]QNB) is inhibited up to 89% by AEA (half-maximal inhibition at 50 microM). Binding of the more polar antagonist [N-methyl-3H]scopolamine ([3H]NMS) is inhibited by AEA up to 76% (half-maximal inhibition at 44 microM). R-methanandamide inhibits more than 90% of both [3H]QNB binding (I50 = 34 microM) and [3H]NMS binding (I50 = 15 microM) to the mAChR. Both AEA and R-methanandamide stimulate mAChR binding of the agonist [3H]oxotremorine-M at low concentrations (25-75 microM), but significantly inhibit agonist binding at higher concentrations (I50 = 150 microM). The cannabinoid antagonist SR141716A did not alter AEA or R-methanandamide inhibition of [3H]NMS binding to the mAChR, even at concentrations as high as 1 microM. Further, the cannabinoid agonist WIN 55212-2 does not alter antagonist binding to the mAChR. This demonstrates that mAChR inhibition by the anandamides is not mediated by the cannabinoid receptor. Since AEA and R-methanandamide are structurally similar to arachidonic acid, they may interact with the mAChR in a similar manner to inhibit receptor function.