Encapsulated Cell Biodelivery Research Articles

Prosaposin maintains lipid homeostasis in dopamine neurons and counteracts experimental parkinsonism in rodents

Prosaposin (PSAP) modulates glycosphingolipid metabolism and variants have been linked to Parkinson’s disease (PD). Here, we find altered PSAP levels in the plasma, CSF and post-mortem brain of PD patients. Altered plasma and CSF PSAP levels correlate with PD-related motor impairments. Dopaminergic PSAP-deficient (cPSAPDAT) mice display hypolocomotion and depression/anxiety-like symptoms with mildly impaired dopaminergic neurotransmission, while serotonergic PSAP-deficient (cPSAPSERT) mice behave normally. Spatial lipidomics revealed an accumulation of highly unsaturated and shortened lipids and reduction of sphingolipids throughout the brains of cPSAPDAT mice. The overexpression of α-synuclein via AAV lead to more severe dopaminergic degeneration and higher p-Ser129 α-synuclein levels in cPSAPDAT mice compared to WT mice. Overexpression of PSAP via AAV and encapsulated cell biodelivery protected against 6-OHDA and α-synuclein toxicity in wild-type rodents. Thus, these findings suggest PSAP may maintain dopaminergic lipid homeostasis, which is dysregulated in PD, and counteract experimental parkinsonism.

Feasibility and therapeutical potential of local intracerebral encapsulated cell biodelivery of BDNF to AppNL-G-F knock-in Alzheimer mice.

Alzheimer's disease (AD) is an age-related disease characterized by altered cognition, neuroinflammation, and neurodegeneration against which there is presently no effective cure. Brain-derived neurotrophic factor (BDNF) is a key neurotrophin involved in the learning and memory process, with a crucial role in synaptic plasticity and neuronal survival. Several findings support that a reduced BDNF expression in the human brain is associated with AD pathogenesis. BDNF has been proposed as a potential therapy for AD, but BDNF has low brain penetration. In this study, we used an innovative encapsulated cell biodelivery (ECB) device, containing genetically modified cells capable of releasing BDNF and characterized its feasibility and therapeutic effects in the novel App knock-in AD mouse model (AppNL-G-F). ECB's containing human ARPE-19 cells genetically modified to release BDNF (ECB-BDNF devices) were stereotactically implanted bilaterally into hippocampus of 3-month-old AppNL-G-F mice. The stability of BDNF release and its effect on AD pathology were evaluated after 1, 2-, and 4-months post-implantation by immunohistochemical and biochemical analyses. Exploratory and memory performance using elevated plus maze (EPM) and Y-maze test were performed in the 4-months treatment group. Immunological reaction towards ECB-BDNF devices were studied under ex vivo and in vivo settings. The surgery and the ECB-BDNF implants were well tolerated without any signs of unwanted side effects or weight loss. ECB-BDNF devices did not induce host-mediated immune response under ex vivo set-up but showed reduced immune cell attachment when explanted 4-months post-implantation. Elevated BDNF staining around ECB-BDNF device proximity was detected after 1, 2, and 4months treatment, but the retrieved devices showed variable BDNF release. A reduction of amyloid-β (Aβ) plaque deposition was observed around ECB-BDNF device proximity after 2-months of BDNF delivery. The result of this study supports the use of ECB device as a promising drug-delivery approach to locally administer BBB-impermeable factors for treating neurodegenerative conditions like AD. Optimization of the mouse-sized devices to reduce variability of BDNF release is needed to employ the ECB platform in future pre-clinical research and therapy development studies.

The microglial challenge to encapsulated cell mediated drug delivery in brain tissue

AbstractBackgroundDementia disorders affect millions of people worldwide, among which Alzheimer’s disease (AD) accounts for 60% cases. Treatment of these disorders are constrained due to inefficient brain availability of peripherally administered drugs. Conversely, direct intracerebroventricular injections are counterintuitive due to unspecific side‐effects. Recently, Aducanumab has shown potential to clear amyloid plaques from AD brain, but its efficacy to revive clinical symptoms are under debate. In this regard, direct delivery of regenerative biological drugs utilizing encapsulated cell biodelivery (ECB) has gained much attention. Conversely, how the pathological microenvironment of the AD brain affects these encapsulated drug‐delivering cells are scarcely understood. The ECB approach nullifies immune reaction from host tissue by protecting drug‐delivering cells from direct physical contact with the host tissue. Thus, in this study we probe the effect of factors released from activated human microglial cells (HMC3 cell line) on ECB devices harboring nerve growth factor (NGF) releasing cells (NGC0211; modified human ARPE‐19 cells).MethodECB devices harboring NGC0211 cells were manufactured and maintained in DMEM/F12 culture medium containing 10% serum until used. HMC3 cells were activated using AD related molecules including 1µM amyloid beta (Aβ40 and Aβ42) peptides and 10ng/mL inflammatory cytokines (interferon‐γ, IFN‐γ; interleukin‐1β, IL‐1β; or both) for 24hrs, and a cell free microglia conditioned medium (MCM) was obtained. ECB devices were then exposed to various MCMs, and NGF release was followed for several weeks assessed by ELISA (DY256, R&D systems). Similarly, non‐encapsulated NGC0211 cells grown in multi‐well slides were exposed to MCMs and cellular proliferation (Ki67 expression) along with senescence parameters (SA‐β‐galactosidase) were evaluated.ResultWe found that factors released from activated microglia hampered NGF release from ECB devices. Simultaneously, MCMs reduced Ki67 expression and elevated SA‐β‐galactosidase activity in NGC0211 cells.ConclusionActivated microglia, a common feature of all neurodegenerative conditions, impair NGF release, cellular proliferation and induce senescence in NGC0211 cells. Similar impact of microglia on other types of drug‐delivering cells (stem cells or genetically modified) needs to be studied. Our study highlights one of the probable underlying causes for impaired long‐term cell mediated drug delivery in neurodegenerative diseases and helps guide improvements in the technologies.

Hippocampal BDNF encapsulated cell bio‐delivery improves spontaneous behavioral alternations in the Y‐maze test in AppNL‐G‐F mice.

AbstractBackgroundAlzheimer’s disease (AD) is an age‐related disease characterized by synaptic dysfunction, brain inflammation, and neurodegeneration against which there is no effective cure available. Brain‐Derived Neurotrophic Factor (BDNF) is a key molecule involved in the learning and memory process, with a crucial role in synaptic plasticity and neuronal survival. Several findings support that a reduced BDNF expression in the human brain is associated with AD pathogenesis. BDNF has been proposed as a potential therapy for AD, but BDNF has low brain permeability. In this study, we used an innovative encapsulated cell biodelivery (ECB) device containing cells capable of locally delivering BDNF to characterize its neuroprotective effects in the novel AD APP‐knock‐in mouse model AppNL‐G‐F.MethodECB devices with human ARPE‐19 cells modified to release BDNF were surgically bilaterally implanted in the hippocampus of 3‐month‐old AppNL‐G‐F mice. BDNF effects on AD pathology were evaluated after 1, 2, and 3 months of treatment by immunohistochemical and biochemical analysis. In the 3‐month‐treated groups, exploratory and memory performances were also evaluated using Elevated Plus Maze (EPM) and Y‐maze tests.ResultThe ECB implants were well tolerated with no signs of unwanted side effects or weight loss. A high BDNF staining was detected in most of the brains in the area surrounding the devices at 1‐3 months, but retrieved devices showed variability of BDNF release. Interestingly, three months of BDNF treatment significantly improved AppNL‐G‐F mice´s anxiety behavior in EPM and improved the spontaneous behavioral alternations in the Y‐maze test.ConclusionThe results of this study are encouraging and support the BDNF device as a promising approach for treating cognitive AD decline. Optimization of the mouse‐sized devices to reduce the variability of BDNF release is needed for future experiments and translated to larger devices for clinical translation.

O003 / #714 COGNITIVE RESTORATION IN ALZHEIMER’S PATIENTS BY LOCAL INTRACEREBRAL CELL-MEDIATED NERVE GROWTH FACTOR DELIVERY: CLINICAL EFFICACY AND FURTHER METHOD OPTIMIZATION: ORAL POSTER PRESENTATIONS FIVE BEST ABSTRACTS

Local neuromodulation of brain functions can be accomplished in many ways: electrical stimulation, local micro-infusion of drugs, implantations of viruses or engineered cells, etc. We have studied targeted encapsulated cell implants delivering active substances locally in Alzheimer patients (AD). AD is associated with early loss of basal forebrain cholinergic neurons (BFCNs) and cognitive dysfunction. BFCNs are dependent on nerve growth factor (NGF). Previously, we have developed an encapsulated cell biodelivery (ECB) platform and utilized it to stimulate BFCNs in two cholinergic target sites (Ch4 [nucl.

Microglia Impairs Proliferation and Induces Senescence In-Vitro in NGF Releasing Cells Used in Encapsulated Cell Biodelivery for Alzheimer's Disease Therapy.

There is no cure yet available for Alzheimer’s disease (AD). We recently optimized encapsulated cell biodelivery (ECB) devices releasing human mature nerve growth factor (hmNGF), termed ECB-NGF, to the basal forebrain of AD patients. The ECB-NGF delivery resulted in increased CSF cholinergic markers, improved glucose metabolism, and positive effects on cognition in AD patients. However, some ECB-NGF implants showed altered hmNGF release post-explantation. To optimize the ECB-NGF platform for future therapeutic purposes, we initiated in-vitro optimization studies by exposing ECB-NGF devices to physiological factors present within the AD brain. We report here that microglia cells can impair hmNGF release from ECB-NGF devices in-vitro, which can be reversed by transferring the devices to fresh culture medium. Further, we exposed the hmNGF secreting human ARPE-19 cell line (NGC0211) to microglia (HMC3) conditioned medium (MCM; untreated or treated with IL-1β/IFNγ/Aβ40/Aβ42), and evaluated biochemical stress markers (ROS, GSH, ΔΨm, and Alamar Blue assay), cell death indicators (Annexin-V/PI), cell proliferation (CFSE retention and Ki67) and senescence markers (SA-β-gal) in NGC0211 cells. MCMs from activated microglia reduced cell proliferation and induced cell senescence in NGC0211 cells, which otherwise resist biochemical alterations and cell death. These data indicate a critical but reversible impact of activated microglia on NGC0211 cells.

Gene and Cell Therapy for Epilepsy: A Mini Review.

Epilepsy is a chronic non-infectious disease of the brain, characterized primarily by recurrent unprovoked seizures, defined as an episode of disturbance of motor, sensory, autonomic, or mental functions resulting from excessive neuronal discharge. Despite the advances in the treatment achieved with the use of antiepileptic drugs and other non-pharmacological therapies, about 30% of patients suffer from uncontrolled seizures. This review summarizes the currently available methods of gene and cell therapy for epilepsy and discusses the development of these approaches. Currently, gene therapy for epilepsy is predominantly adeno-associated virus (AAV)-mediated delivery of genes encoding neuro-modulatory peptides, neurotrophic factors, enzymes, and potassium channels. Cell therapy for epilepsy is represented by the transplantation of several types of cells such as mesenchymal stem cells (MSCs), bone marrow mononuclear cells, neural stem cells, and MSC-derived exosomes. Another approach is encapsulated cell biodelivery, which is the transplantation of genetically modified cells placed in capsules and secreting various therapeutic agents. The use of gene and cell therapy approaches can significantly improve the condition of patient with epilepsy. Therefore, preclinical, and clinical studies have been actively conducted in recent years to prove the benefits and safety of these strategies.

Fast Alpha Activity in EEG of Patients With Alzheimer's Disease Is Paralleled by Changes in Cognition and Cholinergic Markers During Encapsulated Cell Biodelivery of Nerve Growth Factor.

BackgroundBasal forebrain cholinergic neurons are dependent on nerve growth factor (NGF) for growth and survival and these cells are among the first to degenerate in Alzheimer’s disease (AD). Targeted delivery of NGF has been suggested as a potential therapy for AD. This hypothesis was tested in a clinical trial with encapsulated cell biodelivery of NGF (NGF-ECB) in AD patients. Three of six patients showed improved biomarkers for cognition by the end of the study. Here, we report on the effects of targeted delivery of NGF on human resting EEG.Materials and methodsNGF-ECB implants were implanted bilaterally in the basal forebrain of six AD patients for 12 months. EEG recordings and quantitative analysis were performed at baseline, 3 and 12 months of NGF delivery, and analyzed for correlation with changes in Mini-mental state examination (MMSE) and levels of the cholinergic marker choline acetyltransferase (ChAT) in cerebrospinal fluid (CSF).ResultsWe found significant correlations between the topographic variance of EEG spectral power at the three study points (baseline, 3 and 12 months) and changes in MMSE and CSF ChAT. This possible effect of NGF was identified in a narrow window of alpha frequency 10–11.5 Hz, where a stabilization in MMSE score during treatment was related to an increase in EEG alpha power. A similar relation was observed between the alpha power and ChAT. More theta power at 6.5 Hz was on the contrary associated with a decrease in CSF ChAT during the trial period.ConclusionIn this exploratory study, there was a positive correlative pattern between physiological high-frequency alpha activity and stabilization in MMSE and increase in CSF ChAT in AD patients receiving targeted delivery of NGF to the cholinergic basal forebrain.

Considerations for drug delivery utilizing encapsulated cells: Factors for optimal cell behavior

AbstractBackgroundDrug delivery is an important aspect for clinical therapies, but drug delivery to the brain tissue may be restricted by the blood‐brain barrier (BBB), which limits the passage of many molecules when administered peripherally. To achieve direct brain delivery of biological drugs, various techniques have been developed, including encapsulation of live cells within membranes to limit immune mediated host‐rejection (1,2), forming the basis for cell replacement therapies (3,4). Interestingly, the dynamics of cells within the encapsulated membrane (limited space) have been less understood and determinants (prolonged cell proliferation, contact inhibition, cell death, re‐population, debris clearance) which can affect cellular health and its long‐term biological function need more attention. Studying cells (NGC0211) previously used in encapsulated cell‐biodelivery (ECB) devices to treat Alzheimer’s disease (AD) patients (5), the population dynamics of cells when cultured in limited space were investigated.MethodHuman retinal epithelial cells obtained from the ARPE‐19 cell line and genetically modified to release NGF (termed NGC0211) were cultured in 35mm dishes in different conditions (serum containing or serum free) and monitored overtime using light microscope. Cells were cultured for prolonged periods (3‐4 weeks) continuously without splitting to induce space constraints and monitored under the microscope. Simultaneously, medium was changed at different intervals (weekly or every 2 days) to observe effects of nutrient deprivation. To check debris clearance, dying cells were labelled with CFSE and plated on healthy cells stained with CellMask™ Deep Red plasma membrane stain or dye. To check the impact of inflammation, NGC0211 cells were exposed to inflammatory cytokines for various time points.ResultCellular dynamics and morphology of NGC0211 cells changed overtime with repeated cycles of cell death and simultaneous re‐population, indicating the prime role of phasic cell proliferation to maintain a constant population. Inflammatory cytokines affected NGC0211 cell proliferation, indicating the negative impact of inflammation on cellular re‐population.ConclusionLong‐term stability and clinical therapy using encapsulated cells can be affected by the internal dynamics of the cells itself. Inflammation may reduce clinical efficacy by affecting cellular re‐population, thereby reducing the number of viable cells within the encapsulated device overtime.

Amyloid-Beta Peptides and Activated Astroglia Impairs Proliferation of Nerve Growth Factor Releasing Cells In Vitro: Implication for Encapsulated Cell Biodelivery-Mediated AD Therapy

Alzheimer’s disease (AD) treatment is constrained due to the inability of peripherally administered therapeutic molecules to cross the blood–brain barrier. Encapsulated cell biodelivery (ECB) devices, a tissue-targeted approach for local drug release, was previously optimized for human mature nerve growth factor (hmNGF) delivery in AD patients but was found to have reduced hmNGF release over time. To understand the reason behind reduced ECB efficacy, we exposed hmNGF-releasing cells (NGC0211) in vitro to human cerebrospinal fluid (CSF) obtained from Subjective Cognitive Impairment (SCI), Lewy Body Dementia (LBD), and AD patients. Subsequently, we exposed NGC0211 cells directly to AD-related factors like amyloid-β peptides (Aβ40/42) or activated astrocyte-conditioned medium (Aβ40/42/IL-1β/TNFα-treated) and evaluated biochemical stress markers, cell death indicators, cell proliferation marker (Ki67), and hmNGF release. We found that all patients’ CSF significantly reduced hmNGF release from NGC0211 cells in vitro. Aβ40/42, inflammatory molecules, and activated astrocytes significantly affected NGC0211 cell proliferation without altering hmNGF release or other parameters important for essential functions of the NGC0211 cells. Long-term constant cell proliferation within the ECB device is critically important to maintain a steady cell population needed for stable mNGF release. These data show hampered proliferation of NGC0211 cells, which may lead to a decline of the NGC0211 cell population in ECBs, thereby reducing hmNGF release. Our study highlights the need for future studies to strengthen ECB-mediated long-term drug delivery approaches.

Encapsulated cell biodelivery of NGF (ECB‐NGF) for AD therapy has implications from astroglial activation and amyloid‐beta toxicity

AbstractBackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disorder characterised by loss of cholinergic neurons in the basal forebrain (BFCN). Mature Nerve growth factor (mNGF) is required for the survival of BFCN’s, but since it cannot cross blood‐brain barrier (BBB), its tissue targeted delivery via encapsulated cell biodelivery (ECB‐NGF) device has been envisaged as a potential therapeutic strategy. In our previous first‐in‐human studies, we observed some inter‐capsule differences in mNGF release among ECB‐NGF devices, when implanted in human AD patients. To address this issue, we pursued whether amyloid‐beta (Ab40/42) peptides directly or indirectly (by activating astroglial cells) can affect the NGF‐delivering (NGC‐0211) cells.MethodWe tested direct or astrocyte‐mediated (indirect) effect of Ab40 and Ab42 on the NGC‐0211 cells in‐vitro. To study the astrocyte‐mediated effects of Ab peptides, human primary astrocytes were first incubated with Ab peptides and the conditioned medium was further transferred on NGC‐0211 cells. Effects on cell survival (flowcytometry), stress markers (spectrophotometric measurements), cell proliferation (immunocytochemistry) and NGF release (ELISA) were monitored.ResultWe report that Ab‐peptides induced marginal effects on cell survival and NGF release upon direct and indirect stimulation. Astrocyte conditioned media partially modulated biochemical parameters. In both cases of stimulation method, cell proliferative ability of NGC0211 cells was significantly hampered.ConclusionOur data suggests that the survival of the NGC‐0211 cells is not affected by Ab peptides, whereas their proliferation was significantly hampered, directly as well as through astroglial activation. Overall, NGF release was not affected negatively under the conditions and time points tested in this study. This study lays the foundation for further optimization of ECB‐NGF devices for future AD therapy.

The cholinergic system in subtypes of Alzheimer\u2019s disease: an in vivo longitudinal MRI study

BackgroundThe heterogeneity within Alzheimer’s disease (AD) seriously challenges the development of disease-modifying treatments. We investigated volume of the basal forebrain, hippocampus, and precuneus in atrophy subtypes of AD and explored the relevance of subtype stratification in a small clinical trial on encapsulated cell biodelivery (ECB) of nerve growth factor (NGF) to the basal forebrain.MethodsStructural MRI data was collected for 90 amyloid-positive patients and 69 amyloid-negative healthy controls at baseline, 6-, 12-, and 24-month follow-up. The effect of the NGF treatment was investigated in 10 biopsy-verified AD patients with structural MRI data at baseline and at 6- or 12-month follow-up. Patients were classified as typical, limbic-predominant, hippocampal-sparing, or minimal atrophy AD, using a validated visual assessment method. Volumetric analyses were performed using a region-of-interest approach.ResultsAll AD subtypes showed reduced basal forebrain volume as compared with the healthy controls. The limbic-predominant subtype showed the fastest basal forebrain atrophy rate, whereas the minimal atrophy subtype did not show any significant volume decline over time. Atrophy rates of the hippocampus and precuneus also differed across subtypes. Our preliminary data from the small NGF cohort suggest that the NGF treatment seemed to slow the rate of atrophy in the precuneus and hippocampus in some hippocampal-sparing AD patients and in one typical AD patient.ConclusionsThe cholinergic system is differentially affected in distinct atrophy subtypes of AD. Larger studies in the future should confirm that this differential involvement of the cholinergic system may contribute to subtype-specific response to cholinergic treatment. Our preliminary findings suggest that future clinical trials should target specific subtypes of AD, or at least report treatment effects stratified by subtype.Trial registrationClinicalTrials.gov identifier: NCT01163825. Registered 14 July 2010.

Innovative Therapy for Alzheimer's Disease-With Focus on Biodelivery of NGF.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with abnormal protein modification, inflammation and memory impairment. Aggregated amyloid beta (Aβ) and phosphorylated tau proteins are medical diagnostic features. Loss of memory in AD has been associated with central cholinergic dysfunction in basal forebrain, from where the cholinergic circuitry projects to cerebral cortex and hippocampus. Various reports link AD progression with declining activity of cholinergic neurons in basal forebrain. The neurotrophic molecule, nerve growth factor (NGF), plays a major role in the maintenance of cholinergic neurons integrity and function, both during development and adulthood. Numerous studies have also shown that NGF contributes to the survival and regeneration of neurons during aging and in age-related diseases such as AD. Changes in neurotrophic signaling pathways are involved in the aging process and contribute to cholinergic and cognitive decline as observed in AD. Further, gradual dysregulation of neurotrophic factors like NGF and brain derived neurotrophic factor (BDNF) have been reported during AD development thus intensifying further research in targeting these factors as disease modifying therapies against AD. Today, there is no cure available for AD and the effects of the symptomatic treatment like cholinesterase inhibitors (ChEIs) and memantine are transient and moderate. Although many AD treatment studies are being carried out, there has not been any breakthrough and new therapies are thus highly needed. Long-term effective therapy for alleviating cognitive impairment is a major unmet need. Discussion and summarizing the new advancements of using NGF as a potential therapeutic implication in AD are important. In summary, the intent of this review is describing available experimental and clinical data related to AD therapy, priming to gain additional facts associated with the importance of NGF for AD treatment, and encapsulated cell biodelivery (ECB) as an efficient tool for NGF delivery.

Unilateral ex vivo gene therapy by GDNF in epileptic rats.

Temporal lobe epilepsy (TLE) is the most common type of epilepsy in adults. This neurological disorder is characterized by focal seizures originating in the temporal lobe, often with secondary generalization. A variety of pharmacological treatments exist for patients suffering from focal seizures, but systemically administered drugs offer only symptomatic relief and frequently cause unwanted side effects. Moreover, available drugs are ineffective in one third of theepilepsy patients. Thus, developing more targeted and effective treatment strategies for focal seizures, originating from, e.g., the temporal lobe, is highly warranted. In order to deliver potential anti-epileptic agents directly into the seizure focus we used encapsulated cell biodelivery (ECB), a specific type of ex vivo gene therapy. Specifically, we asked whether unilateral delivery of glial cell line-derived neurotrophic factor (GDNF), exclusively into the epileptic focus, would suppress already established spontaneous recurrent seizures (SRS) in rats. Our results show that GDNF delivered by ECB devices unilaterally into the seizure focus in the hippocampus effectively decreases the number of SRS in epileptic rats. Thus, our study demonstrates that focal unilateral delivery of neurotrophic factors, such as GDNF, using ex vivo gene therapy based on ECB devices could be an effective anti-epileptic strategy providing a bases for the development of a novel, alternative, treatment for focal epilepsies.

Cerebrospinal fluid from Alzheimer patients affects cell-mediated nerve growth factor production and cell survival in vitro

Alzheimer's disease (AD) is characterized by early degeneration of cholinergic neurons and decreased levels of nerve growth factor (NGF). Thus, increasing the NGF levels by for instance encapsulated cell bio-delivery (ECB) is a potential treatment strategy. The results from our previous first-in-human studies on ECB of NGF to the basal forebrain cholinergic neurons were promising, but indicated some variability of long-term viability of the encapsulated cells and associated reduced NGF-release. Here we studied the effect of amyloid beta-peptides (Aβ), interleukin 1-beta (IL-1β), and CSF from AD, Lewy body dementia (LBD) or subjective cognitive impairment (SCI) patients on the NGF overproducing cell line NGC-0295. At physiological concentrations, neither Aβ40 nor Aβ42 had any major impact on cell viability or NGF-production. In contrast, IL-1β dose-dependently affected NGF-production over time. Exposure of NGF-producing cells to CSF from AD patients showed significantly reduced NGF-release as compared to CSF from LBD or SCI patients. By mass spectrometry we found 3 proteins involved in inflammatory pathways to have an altered expression in AD CSF compared to LBD and SCI. Cell survival and NGF-release were not affected by Aβ. NGF-release was affected by IL-1β, suggesting that inflammation has a negative effect on ECB cells.

New Tools for Epilepsy Therapy.

One third of the epilepsies are refractory to conventional antiepileptic drugs (AEDs) and, therefore, identification of new therapies is highly needed. Here, we briefly describe two approaches, direct cell grafting and gene therapy, that may represent alternatives to conventional drugs for the treatment of focal epilepsies. In addition, we discuss more in detail some new tools, cell based-biodelivery systems (encapsulated cell biodelivery (ECB) devices) and new generation gene therapy vectors, which may help in the progress toward clinical translation. The field is advancing rapidly, and there is optimism that cell and/or gene therapy strategies will soon be ready for testing in drug-resistant epileptic patients.

Seizure-Suppressant and Neuroprotective Effects of Encapsulated BDNF-Producing Cells in a Rat Model of Temporal Lobe Epilepsy

Brain-derived neurotrophic factor (BDNF) may represent a therapeutic for chronic epilepsy, but evaluating its potential is complicated by difficulties in its delivery to the brain. Here, we describe the effects on epileptic seizures of encapsulated cell biodelivery (ECB) devices filled with genetically modified human cells engineered to release BDNF. These devices, implanted into the hippocampus of pilocarpine-treated rats, highly decreased the frequency of spontaneous seizures by more than 80%. These benefits were associated with improved cognitive performance, as epileptic rats treated with BDNF performed significantly better on a novel object recognition test. Importantly, long-term BDNF delivery did not alter normal behaviors such as general activity or sleep/wake patterns. Detailed immunohistochemical analyses revealed that the neurological benefits of BDNF were associated with several anatomical changes, including reduction in degenerating cells and normalization of hippocampal volume, neuronal counts (including parvalbumin-positive interneurons), and neurogenesis. In conclusion, the present data suggest that BDNF, when continuously released in the epileptic hippocampus, reduces the frequency of generalized seizures, improves cognitive performance, and reverts many histological alterations associated with chronic epilepsy. Thus, ECB device-mediated long-term supplementation of BDNF in the epileptic tissue may represent a valid therapeutic strategy against epilepsy and some of its co-morbidities.

Alzheimer's disease: The role for neurosurgery.

Dementia, most commonly caused by Alzheimer's disease (AD), affects approximately 35 million people worldwide, with the incidence expected to increase as the population ages. After decades of investigation, AD is now understood to be a complex disease that affects behavior and cognition through several mechanisms: Disrupted neuronal communication, abnormal regional tissue metabolism, and impaired cellular repair. Existing therapies have demonstrated limited efficacy, which has spurred the search for specific disease markers and predictors as well as innovative therapeutic options. Deep brain stimulation (DBS) of the memory circuits is one such option, with early studies suggesting that modulation of neural activity in these networks may improve cognitive function. Encapsulated cell biodelivery (ECB) is a device that delivers nerve growth factor to the cholinergic basal forebrain to potentially improve cognitive decline in AD patients. This review discusses the pathogenesis of AD, novel neuroimaging and biochemical markers, and the emerging role for neurosurgical applications such as DBS and ECB.

Encapsulated galanin‐producing cells attenuate focal epileptic seizures in the hippocampus

Encapsulated cell biodelivery (ECB) is a relatively safe approach, since the devices can be removed in the event of adverse effects. The main objectives of the present study were to evaluate whether ECB could be a viable alternative of cell therapy for epilepsy. We therefore developed a human cell line producing galanin, a neuropeptide that has been shown to exert inhibitory effects on seizures, most likely acting via decreasing glutamate release from excitatory synapses. To explore whether ECB of genetically modified galanin-producing human cell line could provide seizure-suppressant effects, and test possible translational prospect for clinical application, we implanted ECB devices bilaterally into the hippocampus of rats subjected to rapid kindling, a model for recurrent temporal lobe seizures. Two clones from a genetically modified human cell line secreting different levels of galanin were tested. Electroencephalography (EEG) recordings and stimulations were performed by electrodes implanted into the hippocampus at the same surgical session as ECB devices. One week after the surgery, rapid kindling stimulations were initiated. Enzyme-linked immunosorbent assay (ELISA) measurements prior to device implantation showed a release of galanin on average of 8.3 ng/mL/24 h per device for the low-releasing clone and 12.6 ng/mL/24 h per device for the high-releasing clone. High-releasing galanin-producing ECB devices moderately decreased stimulation-induced focal afterdischarge duration, whereas low-releasing ECB devices had no significant effect. Our study shows that galanin-releasing ECB devices moderately suppress focal stimulation-induced recurrent seizures. Despite this moderate effect, the study provides conceptual proof that ECB could be a viable alternative approach to cell therapy in humans, with the advantage that the treatment could be terminated by removing these devices from the brain. Thereby, this strategy provides a higher level of safety for future therapeutic applications, in which genetically modified human cell lines that are optimized to produce and release antiepileptic compounds could be clinically evaluated for their seizure-suppressant effects.

Targeted delivery of nerve growth factor via encapsulated cell biodelivery in Alzheimer disease: a technology platform for restorative neurosurgery

The authors describe the first clinical trial with encapsulated cell biodelivery (ECB) implants that deliver nerve growth factor (NGF) to the cholinergic basal forebrain with the intention of halting the degeneration of cholinergic neurons and the associated cognitive decline in patients with Alzheimer disease (AD). The NsG0202 implant (NsGene A/S) consists of an NGF-producing, genetically engineered human cell line encapsulated behind a semipermeable hollow fiber membrane that allows the influx of nutrients and the efflux of NGF. The centimeter-long capsule is attached to an inert polymer tether that is used to guide the capsule to the target via stereotactic techniques and is anchored to the skull at the bur hole. Six patients with mild to moderate AD were included in this Phase Ib open-label safety study and were divided into 2 dose cohorts. The first cohort of 3 patients received single implants targeting the basal nucleus of Meynert (Ch4 region) bilaterally (2 implants per patient), and after a safety evaluation, a second cohort of 3 patients received bilateral implants (a total of 4 implants per patient) targeting both the Ch4 region and the vertical limb of the diagonal band of Broca (Ch2 region). Stereotactic implantation of the devices was successfully accomplished in all patients. Despite extensive brain atrophy, all targets could be reached without traversing sulci, the insula, or lateral ventricles. Postoperative CT scans allowed visualization of the barium-impregnated tethers, and fusion of the scans with stereotactic MR images scan was used to verify the intended positions of the implants. Follow-up MRI at 3 and 12 months postimplantation showed no evidence of inflammation or device displacement. At 12 months, implants were successfully retrieved, and low but persistent NGF secretion was detected in half of the patients. With refinement, the ECB technology is positioned to become an important therapeutic platform in restorative neurosurgery and, in combination with other therapeutic factors, may be relevant for the treatment of a variety of neurological disorders. Clinical trial registration no.: NCT01163825.