Rapid intracerebroventricular delivery of Cu-DOTA-etanercept after peripheral administration demonstrated by PET imaging. BMC Res Notes. 2009;2:28. [PMID: 19284700 PMCID: PMC2651903 DOI: 10.1186/1756-0500-2-28]

Perispinal Etanercept to improve STroke Outcomes (PESTO): Protocol for a multicenter, international, randomized placebo-controlled trial

RATIONALE

A large proportion of stroke survivors will have long-lasting, debilitating neurological impairments, yet few efficacious medical treatment options are available. Etanercept inhibits binding of tumor necrosis factor to its receptor and is used in the treatment of inflammatory conditions. Perispinal subcutaneous injection followed by a supine, head down position may bypass the blood brain barrier. In observational studies and one small randomized controlled trial the majority of patients showed improvement in multiple post stroke impairments.

AIM

Perispinal Etanercept to improve STroke Outcomes (PESTO) investigates whether perispinal subcutaneous injection of etanercept improves quality of life and is safe in patients with chronic, disabling, effects of stroke.

METHODS AND DESIGN

PESTO is a multicenter, international, randomized placebo-controlled trial. Adult participants with a history of stroke between 1 and 15 years before enrollment and a current modified Rankin scale between 2 and 5 who are otherwise eligible for etanercept are randomized 1:1 to single dose injection of etanercept or placebo.

STUDY OUTCOMES

The primary efficacy outcome is quality of life as measured using the Short Form 36 Health Inventory at day 28 after first injection. Safety outcomes include serious adverse events.

SAMPLE SIZE TARGET

A total of 168 participants assuming an improvement of the SF-36 in 11% of participants in the control arm and in 30% of participants in the intervention arm, 80% power and 5% alpha.

DISCUSSION

PESTO aims to provide level 1 evidence on the safety and efficacy of perispinal etanercept in patients with long-term disabling effects of stroke.

Translational molecular imaging and drug development in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that primarily affects elderly people and constitutes a major source of disability worldwide. Notably, the neuropathological hallmarks of PD include nigrostriatal loss and the formation of intracellular inclusion bodies containing misfolded α-synuclein protein aggregates. Cardinal motor symptoms, which include tremor, rigidity and bradykinesia, can effectively be managed with dopaminergic therapy for years following symptom onset. Nonetheless, patients ultimately develop symptoms that no longer fully respond to dopaminergic treatment. Attempts to discover disease-modifying agents have increasingly been supported by translational molecular imaging concepts, targeting the most prominent pathological hallmark of PD, α-synuclein accumulation, as well as other molecular pathways that contribute to the pathophysiology of PD. Indeed, molecular imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can be leveraged to study parkinsonism not only in animal models but also in living patients. For instance, mitochondrial dysfunction can be assessed with probes that target the mitochondrial complex I (MC-I), while nigrostriatal degeneration is typically evaluated with probes designed to non-invasively quantify dopaminergic nerve loss. In addition to dopaminergic imaging, serotonin transporter and N-methyl-D-aspartate (NMDA) receptor probes are increasingly used as research tools to better understand the complexity of neurotransmitter dysregulation in PD. Non-invasive quantification of neuroinflammatory processes is mainly conducted by targeting the translocator protein 18 kDa (TSPO) on activated microglia using established imaging agents. Despite the overwhelming involvement of the brain and brainstem, the pathophysiology of PD is not restricted to the central nervous system (CNS). In fact, PD also affects various peripheral organs such as the heart and gastrointestinal tract - primarily via autonomic dysfunction. As such, research into peripheral biomarkers has taken advantage of cardiac autonomic denervation in PD, allowing the differential diagnosis between PD and multiple system atrophy with probes that visualize sympathetic nerve terminals in the myocardium. Further, α-synuclein has recently gained attention as a potential peripheral biomarker in PD. This review discusses breakthrough discoveries that have led to the contemporary molecular concepts of PD pathophysiology and how they can be harnessed to develop effective imaging probes and therapeutic agents. Further, we will shed light on potential future trends, thereby focusing on potential novel diagnostic tracers and disease-modifying therapeutic interventions.

Targeting Differential Roles of Tumor Necrosis Factor Receptors as a Therapeutic Strategy for Glaucoma

Glaucoma is an irreversible sight-threatening disorder primarily due to elevated intraocular pressure (IOP), leading to retinal ganglion cell (RGC) death by apoptosis with subsequent loss of optic nerve fibers. A considerable amount of empirical evidence has shown the significant association between tumor necrosis factor cytokine (TNF; TNFα) and glaucoma; however, the exact role of TNF in glaucoma progression remains unclear. Total inhibition of TNF against its receptors can cause side effects, although this is not the case when using selective inhibitors. In addition, TNF exerts its antithetic roles via stimulation of two receptors, TNF receptor I (TNFR1) and TNF receptor II (TNFR2). The pro-inflammatory responses and proapoptotic signaling pathways predominantly mediated through TNFR1, while neuroprotective and anti-apoptotic signals induced by TNFR2. In this review, we attempt to discuss the involvement of TNF receptors (TNFRs) and their signaling pathway in ocular tissues with focus on RGC and glial cells in glaucoma. This review also outlines the potential application TNFRs agonist and/or antagonists as neuroprotective strategy from a therapeutic standpoint. Taken together, a better understanding of the function of TNFRs may lead to the development of a treatment for glaucoma.

Chronic cerebral aspects of long COVID, post-stroke syndromes and similar states share their pathogenesis and perispinal etanercept treatment logic

The chronic neurological aspects of traumatic brain injury, post‐stroke syndromes, long COVID‐19, persistent Lyme disease, and influenza encephalopathy having close pathophysiological parallels that warrant being investigated in an integrated manner. A mechanism, common to all, for this persistence of the range of symptoms common to these conditions is described. While TNF maintains cerebral homeostasis, its excessive production through either pathogen‐associated molecular patterns or damage‐associated molecular patterns activity associates with the persistence of the symptoms common across both infectious and non‐infectious conditions. The case is made that this shared chronicity arises from a positive feedback loop causing the persistence of the activation of microglia by the TNF that these cells generate. Lowering this excess TNF is the logical way to reducing this persistent, TNF‐maintained, microglial activation. While too large to negotiate the blood‐brain barrier effectively, the specific anti‐TNF biological, etanercept, shows promise when administered by the perispinal route, which allows it to bypass this obstruction.

Randomized controlled trial validating the use of perispinal etanercept to reduce post-stroke disability has wide-ranging implications

Developing effective drug treatments for neurodegenerative disorders has always been hamstrung by the accepted inability of large molecules (roughly those with a molecular weight greater than 600 Daltons) to cross the blood-brain barrier (BBB) in therapeutic quantities when administered systemically. The dogma has been that a simple, noninvasive way to accomplish this goal is not possible with many agents, including biologicals, because they are too large. Various novel technologies to breach the BBB have been attempted, but with little success. A randomized double-blind, placebo-controlled clinical trial (RCT) administering a widely used anti-tumor necrosis factor (TNF) biological, etanercept, given via perispinal injection, which bypasses the BBB, turns this dogma on its head. This new trial holds much promise for stroke survivors, as well as having implications for developing treatments based on other large molecules for this and other brain disorders.

Antibody-Based Tracers for PET/SPECT Imaging of Chronic Inflammatory Diseases

Chronic inflammatory diseases are often progressive, resulting not only in physical damage to patients but also social and economic burdens, making early diagnosis of them critical. Nuclear medicine techniques can enhance the detection of inflammation by providing functional as well as anatomical information when combined with other modalities such as magnetic resonance imaging, computed tomography or ultrasonography. Although small molecules and peptides were mainly used for the treatment and imaging of chronic inflammatory diseases in the past, antibodies and their fragments have also been emerging for chronic inflammatory diseases as they show high specificity to their targets and can have various biological half-lives depending on how they are engineered. In addition, imaging with antibodies or their fragments can visualize the in vivo biodistribution of the probes or help monitor therapeutic responses, thereby providing physicians with a greater understanding of drug behavior in vivo and another means of monitoring their patients. In this review, we introduce various targets and radiolabeled antibody-based probes for the molecular imaging of chronic inflammatory diseases in preclinical and clinical studies. Targets can be classified into three different categories: 1) cell-adhesion molecules, 2) surface markers on immune cells, and 3) cytokines or enzymes. The limitations and future directions of using radiolabeled antibodies for imaging inflammatory diseases are also discussed.

Clinical Imaging of Choroid Plexus in Health and in Brain Disorders: A Mini-Review

The choroid plexuses (ChPs) perform indispensable functions for the development, maintenance and functioning of the brain. Although they have gained considerable interest in the last years, their involvement in brain disorders is still largely unknown, notably because their deep location inside the brain hampers non-invasive investigations. Imaging tools have become instrumental to the diagnosis and pathophysiological study of neurological and neuropsychiatric diseases. This review summarizes the knowledge that has been gathered from the clinical imaging of ChPs in health and brain disorders not related to ChP pathologies. Results are discussed in the light of pre-clinical imaging studies. As seen in this review, to date, most clinical imaging studies of ChPs have used disease-free human subjects to demonstrate the value of different imaging biomarkers (ChP size, perfusion/permeability, glucose metabolism, inflammation), sometimes combined with the study of normal aging. Although very few studies have actually tested the value of ChP imaging biomarkers in patients with brain disorders, these pioneer studies identified ChP changes that are promising data for a better understanding and follow-up of diseases such as schizophrenia, epilepsy and Alzheimer’s disease. Imaging of immune cell trafficking at the ChPs has remained limited to pre-clinical studies so far but has the potential to be translated in patients for example using MRI coupled with the injection of iron oxide nanoparticles. Future investigations should aim at confirming and extending these findings and at developing translational molecular imaging tools for bridging the gap between basic molecular and cellular neuroscience and clinical research.

Targeting TNFR2 as a Novel Therapeutic Strategy for Alzheimer's Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Accumulating experimental evidence shows the important linkage between tumor necrosis factor-α (TNF) and AD, but the exact role of TNF in AD is still not completely understood. Although TNF-inhibitors are successfully used for treating several diseases, total inhibition of TNF can cause side effects, particularly in neurological diseases. This is attributed to the opposing roles of the two TNF receptors. TNF receptor 1 (TNFR1) predominantly mediates inflammatory and pro-apoptotic signaling pathways, whereas TNF receptor 2 (TNFR2) is neuroprotective and promotes tissue regeneration. Therefore, the specific activation of TNFR2 signaling, either by directly targeting TNFR2 via TNFR2 agonists or by blocking TNFR1 signaling with TNFR1-selective antagonists, seems a promising strategy for AD therapy. This mini-review discusses the involvement of TNFR2 and its signaling pathway in AD and outlines its potential application as therapeutic target. A better understanding of the function of TNFR2 may lead to the development of a treatment for AD.

Targeting tumor necrosis factor in the brain relieves neuropathic pain

Neuropathic pain is a chronic syndrome caused by direct damage to or disease of the somatosensory nervous system. The lack of safe, adequate and sustained pain relief offered by present analgesic treatments is most alarming. While many treatment options are available to manage chronic pain, such as antidepressants, non-steroidal anti-inflammatory agents, opioids, and anticonvulsants, chronic neuropathic pain remains largely unmanaged. Compounding the dilemma of ineffective chronic pain treatments is the need to provide relief from suffering and yet not contribute to the scourge of drug abuse. A recent epidemic of addiction and accidental drug prescription overdoses parallel the increased use of opioid treatment, even though opioids are rarely an effective treatment of relieving chronic pain. To make matters worse, opioids may contribute to exacerbating pain, and side-effects such as cognitive impairment, nausea, constipation, development of tolerance, as well as their potential for addiction and overdose deaths exist. Clearly, there is an urgent need for alternative, non-opiate treatment of chronic pain. Innovative discoveries of pertinent brain mechanisms and functions are key to developing effective, safe treatments. Pioneering work has revealed the essential effects of the pleiotropic mediator tumor necrosis factor (TNF) on brain functioning. These studies establish that TNF inhibits norepinephrine release from hippocampal neurons, and show that excess TNF production within the hippocampus occurs during neuropathic pain, which mobilizes additional mechanisms that further inhibit norepinephrine release. Significantly, it has been verified that elevated levels of TNF in the brain are actually required for neuropathic pain development. Since TNF decreases norepinephrine release in the brain, enhanced TNF levels would prevent engagement of the norepinephrine descending inhibitory neuronal pain pathways. Increased levels of TNF in the brain are therefore critical to the development of neuropathic pain. Therefore, strategies that decrease this enhanced TNF expression in the brain will have superior analgesic efficacy. We propose this novel approach of targeting the pathologically high levels of brain TNF as an effective strategy in the treatment of the devastating syndrome of chronic pain.

Targeting Tumor Necrosis Factor Alpha for Alzheimer's Disease

Alzheimer's disease (AD) affects an estimated 44 million individuals worldwide, yet no therapeutic intervention is available to stop the progression of the dementia. Neuropathological hallmarks of AD are extracellular deposits of amyloid beta (Aβ) peptides assembled in plaques, intraneuronal accumulation of hyperphosphorylated tau protein forming tangles, and chronic inflammation. A pivotal molecule in inflammation is the pro-inflammatory cytokine TNF-α. Several lines of evidence using genetic and pharmacological manipulations indicate that TNF-α signaling exacerbates both Aβ and tau pathologies in vivo. Interestingly, preventive and intervention anti-inflammatory strategies demonstrated a reduction in brain pathology and an amelioration of cognitive function in rodent models of AD. Phase I and IIa clinical trials suggest that TNF-α inhibitors might slow down cognitive decline and improve daily activities in AD patients. In the present review, we summarize the evidence pointing towards a beneficial role of anti-TNF-α therapies to prevent or slow the progression of AD. We also present possible physical and pharmacological interventions to modulate TNF-α signaling in AD subjects along with their limitations.

Perispinal Delivery of CNS Drugs

Perispinal injection is a novel emerging method of drug delivery to the central nervous system (CNS). Physiological barriers prevent macromolecules from efficiently penetrating into the CNS after systemic administration. Perispinal injection is designed to use the cerebrospinal venous system (CSVS) to enhance delivery of drugs to the CNS. It delivers a substance into the anatomic area posterior to the ligamentum flavum, an anatomic region drained by the external vertebral venous plexus (EVVP), a division of the CSVS. Blood within the EVVP communicates with the deeper venous plexuses of the CSVS. The anatomical basis for this method originates in the detailed studies of the CSVS published in 1819 by the French anatomist Gilbert Breschet. By the turn of the century, Breschet's findings were nearly forgotten, until rediscovered by American anatomist Oscar Batson in 1940. Batson confirmed the unique, linear, bidirectional and retrograde flow of blood between the spinal and cerebral divisions of the CSVS, made possible by the absence of venous valves. Recently, additional supporting evidence was discovered in the publications of American neurologist Corning. Analysis suggests that Corning's famous first use of cocaine for spinal anesthesia in 1885 was in fact based on Breschet's anatomical findings, and accomplished by perispinal injection. The therapeutic potential of perispinal injection for CNS disorders is highlighted by the rapid neurological improvement in patients with otherwise intractable neuroinflammatory disorders that may ensue following perispinal etanercept administration. Perispinal delivery merits intense investigation as a new method of enhanced delivery of macromolecules to the CNS and related structures.

Alzheimer's Disease: Exploring the Role of Inflammation and Implications for Treatment

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by both structural abnormalities and inflammation in the brain. While recent research has chiefly focused on the structural changes involved in AD, understanding the pathophysiology and associated inflammation of the AD brain helps to elucidate potential therapeutic and preventative options. By exploring the data supporting an inflammatory etiology of AD, we present a case for the use of existing evidence-based treatments addressing inflammation as promising options for treating and preventing AD. We present data demonstrating tumor necrosis factor alpha association with the inflammation of AD. We also discuss data supporting TNF alpha associated inflammation in traumatic brain injury, stroke, and spinal disc associated radiculopathy. We augment this previously unarticulated concept of a unifying pathophysiology of central nervous system disease, with reports of benefits of TNF alpha inhibition in many hundreds of patients with those diseases, including AD. We also assess the pathophysiologic and clinical trial evidence supporting the role of other inflammation resolving treatments in AD. In aggregate, the data from the several potentially effective therapeutic and preventative options contained within this report presents a clearer picture of next steps needed in research of treatment alternatives.

Central delivery of iodine-125-labeled cetuximab, etanercept and anakinra after perispinal injection in rats: possible implications for treating Alzheimer's disease

Introduction

Alzheimer’s disease is a debilitating condition, and the search for an effective treatment is ongoing. Inflammation, in reaction to amyloid deposition, is thought to accelerate cognitive decline. With tumor necrosis factor α being an important proinflammatory cytokine, a recent trial investigated the effect of the tumor necrosis factor α inhibitor etanercept after peripheral administration in patients with Alzheimer’s disease. Although there was no significant effect, others have claimed spectacular effects of etanercept after perispinal injection. In the present study, the central delivery of drugs with a large molecular weight was evaluated after injection in the cervical perispinal region in rats. If successful, this strategy might increase therapeutic options for patients with Alzheimer’s disease.

Methods

Nine male Sprague–Dawley rats were given injections of iodine-125–labeled cetuximab (146 kDa), etanercept (51 kDa), and anakinra (17 kDa). Each radioiodinated drug was injected in the perispinal region in two rats and into the dorsal tail vein in one rat. Directly after injection, the rats were placed in a head-down position for 3 minutes to direct blood flow into the valveless vertebral venous system. A single-positron emission computed tomography scan was acquired starting 5 minutes after injection, subsequently the rats were euthanized and bio-distribution was determined.  

Results

Intracranial delivery of the radiolabeled drugs could not be visualized in all but one of the rats. Injected drugs accumulated locally in the perispinal region.

Conclusions

In this study, no evidence could be found for the delivery of drugs to the central nervous system after perispinal injection. Additional research is needed before this treatment can be used in patients with Alzheimer’s disease.

Insulin resistance, neuroinflammation, and Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia. Pathologically, it is characterized by degeneration of neurons and synapses, the deposition of extracellular plaques consisting of aggregated amyloid-β (Aβ) peptides, and intracellular neurofibrillary tangles made up of hyperphosphorylated tau protein. Recently, the spotlights have been centered on two characteristics of AD, neuroinflammation and insulin resistance. Because both of these pathways play roles in synaptic dysfunction and neurodegeneration, they become potential targets for therapeutic intervention that could impede the progression of the disease. Here, we present an overview of the traditional amyloid hypothesis, as well as emerging data on both inflammatory and impaired insulin signaling pathways in AD. It becomes evident that more than one concurrent treatment can be synergistic and various combinations should be discussed as a potential therapeutic strategy to correct the anomalies in AD. Insulin resistance, Aβ/tau pathologies, neuroinflammation, and dysregulation of central nervous system homeostasis are intertwined processes that together create the complex pathology of AD and should be considered as a whole picture.

Etanercept in Alzheimer disease: A randomized, placebo-controlled, double-blind, phase 2 trial

OBJECTIVES

To determine whether the tumor necrosis factor α inhibitor etanercept is well tolerated and obtain preliminary data on its safety in Alzheimer disease dementia.

METHODS

In a double-blind study, patients with mild to moderate Alzheimer disease dementia were randomized (1:1) to subcutaneous etanercept (50 mg) once weekly or identical placebo over a 24-week period. Tolerability and safety of this medication was recorded including secondary outcomes of cognition, global function, behavior, and systemic cytokine levels at baseline, 12 weeks, 24 weeks, and following a 4-week washout period. This trial is registered with EudraCT (2009-013400-31) and ClinicalTrials.gov (NCT01068353).

RESULTS

Forty-one participants (mean age 72.4 years; 61% men) were randomized to etanercept (n = 20) or placebo (n = 21). Etanercept was well tolerated; 90% of participants (18/20) completed the study compared with 71% (15/21) in the placebo group. Although infections were more common in the etanercept group, there were no serious adverse events or new safety concerns. While there were some interesting trends that favored etanercept, there were no statistically significant changes in cognition, behavior, or global function.

CONCLUSIONS

This study showed that subcutaneous etanercept (50 mg/wk) was well tolerated in this small group of patients with Alzheimer disease dementia, but a larger more heterogeneous group needs to be tested before recommending its use for broader groups of patients.

CLASSIFICATION OF EVIDENCE

This study shows Class I evidence that weekly subcutaneous etanercept is well tolerated in Alzheimer disease dementia.

Perispinal etanercept for post-stroke neurological and cognitive dysfunction: scientific rationale and current evidence

There is increasing recognition of the involvement of the immune signaling molecule, tumor necrosis factor (TNF), in the pathophysiology of stroke and chronic brain dysfunction. TNF plays an important role both in modulating synaptic function and in the pathogenesis of neuropathic pain. Etanercept is a recombinant therapeutic that neutralizes pathologic levels of TNF. Brain imaging has demonstrated chronic intracerebral microglial activation and neuroinflammation following stroke and other forms of acute brain injury. Activated microglia release TNF, which mediates neurotoxicity in the stroke penumbra. Recent observational studies have reported rapid and sustained improvement in chronic post-stroke neurological and cognitive dysfunction following perispinal administration of etanercept. The biological plausibility of these results is supported by independent evidence demonstrating reduction in cognitive dysfunction, neuropathic pain, and microglial activation following the use of etanercept, as well as multiple studies reporting improvement in stroke outcome and cognitive impairment following therapeutic strategies designed to inhibit TNF. The causal association between etanercept treatment and reduction in post-stroke disability satisfy all of the Bradford Hill Criteria: strength of the association; consistency; specificity; temporality; biological gradient; biological plausibility; coherence; experimental evidence; and analogy. Recognition that chronic microglial activation and pathologic TNF concentration are targets that may be therapeutically addressed for years following stroke and other forms of acute brain injury provides an exciting new direction for research and treatment.

Selective TNF inhibition for chronic stroke and traumatic brain injury: an observational study involving 629 consecutive patients treated with perispinal etanercept

BACKGROUND

Brain injury from stroke and traumatic brain injury (TBI) may result in a persistent neuroinflammatory response in the injury penumbra. This response may include microglial activation and excess levels of tumour necrosis factor (TNF). Previous experimental data suggest that etanercept, a selective TNF inhibitor, has the ability to ameliorate microglial activation and modulate the adverse synaptic effects of excess TNF. Perispinal administration may enhance etanercept delivery across the blood-CSF barrier.

OBJECTIVE

The objective of this study was to systematically examine the clinical response following perispinal administration of etanercept in a cohort of patients with chronic neurological dysfunction after stroke and TBI.

METHODS

After approval by an independent external institutional review board (IRB), a chart review of all patients with chronic neurological dysfunction following stroke or TBI who were treated open-label with perispinal etanercept (PSE) from November 1, 2010 to July 14, 2012 at a group medical practice was performed.

RESULTS

The treated cohort included 629 consecutive patients. Charts of 617 patients following stroke and 12 patients following TBI were reviewed. The mean age of the stroke patients was 65.8 years ± 13.15 (range 13-97). The mean interval between treatment with PSE and stroke was 42.0 ± 57.84 months (range 0.5-419); for TBI the mean interval was 115.2 ± 160.22 months (range 4-537). Statistically significant improvements in motor impairment, spasticity, sensory impairment, cognition, psychological/behavioural function, aphasia and pain were noted in the stroke group, with a wide variety of additional clinical improvements noted in individuals, such as reductions in pseudobulbar affect and urinary incontinence. Improvements in multiple domains were typical. Significant improvement was noted irrespective of the length of time before treatment was initiated; there was evidence of a strong treatment effect even in the subgroup of patients treated more than 10 years after stroke and TBI. In the TBI cohort, motor impairment and spasticity were statistically significantly reduced.

DISCUSSION

Irrespective of the methodological limitations, the present results provide clinical evidence that stroke and TBI may lead to a persistent and ongoing neuroinflammatory response in the brain that is amenable to therapeutic intervention by selective inhibition of TNF, even years after the acute injury.

CONCLUSION

Excess TNF contributes to chronic neurological, neuropsychiatric and clinical impairment after stroke and TBI. Perispinal administration of etanercept produces clinical improvement in patients with chronic neurological dysfunction following stroke and TBI. The therapeutic window extends beyond a decade after stroke and TBI. Randomized clinical trials will be necessary to further quantify and characterize the clinical response.

Is TNF a link between aging-related reproductive endocrine dyscrasia and Alzheimer's disease?

This commentary addresses a novel mechanism by which aging-related changes in reproductive hormones could mediate their action in the brain. It presents the evidence that dyotic endocrine signals modulate the expression of tumor necrosis factor (TNF) and related cytokines, and that these cytokines are a functionally important downstream link mediating neurodegeneration and dysfunction. This convergence of dyotic signaling on TNF-mediated degeneration and dysfunction has important implications for understanding the pathophysiology of AD, stroke, and traumatic brain disease, and also for the treatment of these diseases.

Rapid improvement of chronic stroke deficits after perispinal etanercept: three consecutive cases

BACKGROUND

Thrombolytic therapy reduces stroke size and disability by reperfusion and salvage of ischaemic penumbra. Emerging evidence suggests that retrieved penumbra may be the site of ongoing inflammatory pathology that includes extensive microglial activation. Microglial activation may be associated with excessive levels of tumour necrosis factor (TNF) and resultant neurotoxicity. Etanercept, a potent biologic TNF antagonist, reduces microglial activation in experimental models and has been therapeutically effective in models of brain and neuronal injury. Perispinal administration of etanercept, previously reported to be beneficial for the treatment of Alzheimer's disease, may facilitate delivery of etanercept into the brain.

OBJECTIVE

The objective of this report is to document the initial clinical response to perispinal etanercept in the first chronic stroke cohort so treated.

METHODS

Three consecutive patients with stable and persistent chronic neurological deficits due to strokes that had failed to resolve despite previous treatment and rehabilitation were evaluated at an outpatient clinic. They were treated off-label with perispinal etanercept as part of the clinic's practice of medicine.

RESULTS

All three patients had chronic hemiparesis, in addition to other stroke deficits. Their stroke distributions were right middle cerebral artery (MCA), brainstem (medulla) and left MCA. The two patients with MCA strokes had both received acute thrombolytic therapy. Each of the three patients was treated with an initial dose of perispinal etanercept 13, 35 and 36 months following their acute stroke, respectively. Significant clinical improvement following perispinal etanercept administration was observed in all patients. Onset of clinical response was evident within 10 minutes of perispinal injection in all patients. Improvements in hemiparesis, gait, hand function, hemi-sensory deficits, spatial perception, speech, cognition and behaviour were noted among the patients treated. Each patient received a second perispinal etanercept dose at 22-26 days after the first dose that was followed by additional clinical improvement.

CONCLUSIONS

Open-label administration of perispinal etanercept resulted in rapid neurological improvement in three consecutive patients with chronic neurological dysfunction due to strokes occurring 13-36 months earlier. These results suggest that stroke may result in chronic TNF-mediated pathophysiology that may be amenable to therapeutic intervention long after the acute event. Randomized clinical trials of perispinal etanercept for selected patients with chronic neurological dysfunction following stroke are indicated.

Anti-TNF-α reduces amyloid plaques and tau phosphorylation and induces CD11c-positive dendritic-like cell in the APP/PS1 transgenic mouse brains

Inflammation plays an important role in the pathogenesis of Alzheimer's disease (AD). Overexpression of tumor necrosis factor-α (TNF-α) occurs in the AD brain. Recent clinical studies have shown that the anti-TNF-α therapy improves cognition function of AD patients rapidly. However, the underlying mechanism remains elusive. The present study investigates the effects of intracerebroventricular injection of the monoclonal TNF-α antibody, Infliximab, on the pathological features of AD in the APP/PS1 double transgenic mice. We found that Infliximab administration reduced the levels of TNF-α, amyloid plaques, and tau phosphorylation as early as three days after daily injection of 150 μg Infliximab for three days. The number of CD11c-positive dendritic-like cells and the expression of CD11c were found to be increased concurrently after Infliximab injection. These data suggested that the CD11c-positive dendritic-like cells might contribute to the Infliximab-induced reduction of AD-like pathology. Furthermore, our results support the use of anti-TNF-α for the treatment of AD.

Tumour necrosis factor modulation for treatment of Alzheimer's disease: rationale and current evidence

Tumour necrosis factor (TNF), a key regulator of varied physiological mechanisms in multiple organ systems, is an immune signalling molecule produced by glia, neurons, macrophages and other immune cells. In the brain, among other functions, TNF serves as a gliotransmitter, secreted by glial cells that envelope and surround synapses, which regulates synaptic communication between neurons. The role of TNF as a gliotransmitter may help explain the profound synaptic effects of TNF that have been demonstrated in the hippocampus, in the spinal cord and in a variety of experimental models. Excess TNF is present in the CSF of individuals with Alzheimer's disease (AD), and has been implicated as a mediator of the synaptic dysfunction that is hypothesized to play a central role in the pathogenesis of AD. TNF may also play a role in endothelial and microvascular dysfunction in AD, and in amyloidogenesis and amyloid-induced memory dysfunction in AD. Genetic and epidemiological evidence has implicated increased TNF production as a risk factor for AD. Perispinal administration of etanercept, a potent anti-TNF fusion protein, produced sustained clinical improvement in a 6-month, open-label pilot study in patients with AD ranging from mild to severe. Subsequent case studies have documented rapid clinical improvement following perispinal etanercept in both AD and primary progressive aphasia, providing evidence of rapidly reversible, TNF-dependent, pathophysiological mechanisms in AD and related disorders. Perispinal etanercept for AD merits further study in randomized clinical trials.