Pooled Subject-Reported Outcomes From 2 Phase 3 Studies of OnabotulinumtoxinA for Simultaneous Treatment of Forehead and Glabellar Lines.

BACKGROUND: Understanding the subjects' perspective is critical for successfully treating upper facial lines. OBJECTIVE: To understand subjects' self-perception and overall satisfaction after onabotulinumtoxinA treatment for forehead and glabellar lines. METHODS: This analysis pooled data from two 12-month, pivotal phase 3 studies in which toxin-naive subjects received onabotulinumtoxinA 40 U or placebo for treatment of upper facial lines. OnabotulinumtoxinA was administered as 0.1-mL injections at 10 prespecified sites (frontalis: 20 U; glabellar complex: 20 U). Each study used 3 reliable and validated patient-reported outcome instruments to evaluate subject satisfaction and appearance-related psychological effects: the Facial Line Satisfaction Questionnaire (FLSQ), the Facial Line Outcomes (FLO-11) Questionnaire, and the Self-Perception of Age (SPA) Questionnaire. In total, data for 865 subjects (608, onabotulinumtoxinA 40 U; 257, placebo) were analyzed. RESULTS: Treatment with onabotulinumtoxinA 40 U resulted in significant and sustained improvements across all pooled FLO-11 items and FLSQ items compared with placebo. SPA results demonstrated that a significant proportion of subjects in the pooled analysis felt they looked younger after treatment than at baseline (all, p < .0001 vs placebo). CONCLUSION: This study demonstrates a high level of treatment satisfaction and significantly improved appearance-related psychological outcomes among toxin-naive subjects after onabotulinumtoxinA 40 U treatment.

Phase 3 Study of OnabotulinumtoxinA Distributed Between Frontalis, Glabellar Complex, and Lateral Canthal Areas for Treatment of Upper Facial Lines.

BACKGROUND: Although commonly practiced, simultaneous onabotulinumtoxinA injections to multiple facial areas have not been investigated in prospective studies. OBJECTIVE: Evaluate safety and efficacy of onabotulinumtoxinA for treatment of forehead lines (FHL) distributed between the frontalis (20 U) and glabellar complex (20 U), with or without simultaneous lateral canthal areas (crow's feet lines [CFL], 24 U) treatment. METHODS: Subjects with moderate to severe FHL were randomized (2:2:1) to onabotulinumtoxinA 40 U, onabotulinumtoxinA 64 U, or placebo. After 180 days, subjects could receive up to 2 additional open-label onabotulinumtoxinA 64 U treatments. RESULTS: The intent-to-treat (ITT) population comprised 787 subjects, and the modified ITT (mITT) population (subjects with psychological impact) comprised 568. After 30 days, onabotulinumtoxinA 40 U and 64 U significantly improved investigator- and subject-assessed FHL severity by at least 2 Facial Wrinkle Scale (FWS) grades in 45.6% and 53.0% of ITT subjects, respectively, versus 0.6% receiving placebo (both, p < .0001). Significantly more mITT subjects receiving onabotulinumtoxinA achieved investigator- and subject-assessed FWS ratings of none/mild versus placebo (p < .0001). OnabotulinumtoxinA was well tolerated. CONCLUSION: OnabotulinumtoxinA distributed between the frontalis and glabellar complex, with or without additional CFL injections, was safe and effective for treatment of moderate to severe FHL.

Forehead Line Treatment With OnabotulinumtoxinA in Subjects With Forehead and Glabellar Facial Rhytids: A Phase 3 Study.

BACKGROUND: Effacement of horizontal forehead lines (FHL) with onabotulinumtoxinA has not been investigated in prospective Phase 3 studies. OBJECTIVE: To evaluate safety and efficacy of onabotulinumtoxinA treatment of FHL together with glabellar lines (GL). MATERIALS AND METHODS: A 12-month, Phase 3 study randomized subjects with moderate-to-severe FHL and GL to onabotulinumtoxinA 40 U or placebo, distributed between the frontalis (20 U) and glabellar complex (20 U). After Day 180, subjects could receive up to 2 additional open-label onabotulinumtoxinA treatments. Efficacy was assessed using the Facial Wrinkle Scale (FWS) and Facial Line Outcomes questionnaire. RESULTS: The intent-to-treat (ITT) population included 391 subjects, and the modified ITT (mITT) population (subjects with psychological impact) included 254 subjects. After 30 days, onabotulinumtoxinA significantly improved the investigator- and subject-assessed appearance of FHL severity by at least 2 FWS grades in 61.4% of ITT subjects versus 0% of placebo subjects (p < .0001). In the mITT population, 94.8% of onabotulinumtoxinA subjects and 1.7% of placebo subjects achieved investigator- and subject-assessed FWS ratings of none/mild (p = .0003). Patient-reported outcomes were consistent with FWS ratings. OnabotulinumtoxinA was well tolerated. CONCLUSION: OnabotulinumtoxinA 40 U distributed between the frontalis and glabellar complex was safe and effective for treatment of moderate-to-severe FHL.

Changes in neuronal dopamine homeostasis following 1-methyl-4-phenylpyridinium (MPP+) exposure.

1-Methyl-4-phenylpyridinium (MPP(+)), the active metabolite of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, selectively kills dopaminergic neurons in vivo and in vitro via a variety of toxic mechanisms, including mitochondrial dysfunction, generation of peroxynitrite, induction of apoptosis, and oxidative stress due to disruption of vesicular dopamine (DA) storage. To investigate the effects of acute MPP(+) exposure on neuronal DA homeostasis, we measured stimulation-dependent DA release and non-exocytotic DA efflux from mouse striatal slices and extracellular, intracellular, and cytosolic DA (DAcyt) levels in cultured mouse ventral midbrain neurons. In acute striatal slices, MPP(+) exposure gradually decreased stimulation-dependent DA release, followed by massive DA efflux that was dependent on MPP(+) concentration, temperature, and DA uptake transporter activity. Similarly, in mouse midbrain neuronal cultures, MPP(+) depleted vesicular DA storage accompanied by an elevation of cytosolic and extracellular DA levels. In neuronal cell bodies, increased DAcyt was not due to transmitter leakage from synaptic vesicles but rather to competitive MPP(+)-dependent inhibition of monoamine oxidase activity. Accordingly, monoamine oxidase blockers pargyline and l-deprenyl had no effect on DAcyt levels in MPP(+)-treated cells and produced only a moderate effect on the survival of dopaminergic neurons treated with the toxin. In contrast, depletion of intracellular DA by blocking neurotransmitter synthesis resulted in ∼30% reduction of MPP(+)-mediated toxicity, whereas overexpression of VMAT2 completely rescued dopaminergic neurons. These results demonstrate the utility of comprehensive analysis of DA metabolism using various electrochemical methods and reveal the complexity of the effects of MPP(+) on neuronal DA homeostasis and neurotoxicity.

Alpha-synuclein overexpression in PC12 and chromaffin cells impairs catecholamine release by interfering with a late step in exocytosis.

Alpha-synuclein (alpha-syn), a protein implicated in Parkinson's disease pathogenesis, is a presynaptic protein suggested to regulate transmitter release. We explored how alpha-syn overexpression in PC12 and chromaffin cells, which exhibit low endogenous alpha-syn levels relative to neurons, affects catecholamine release. Overexpression of wild-type or A30P mutant alpha-syn in PC12 cell lines inhibited evoked catecholamine release without altering calcium threshold or cooperativity of release. Electron micrographs revealed that vesicular pools were not reduced but that, on the contrary, a marked accumulation of morphologically "docked" vesicles was apparent in the alpha-syn-overexpressing lines. We used amperometric recordings from chromaffin cells derived from mice that overexpress A30P or wild-type (WT) alpha-syn, as well as chromaffin cells from control and alpha-syn null mice, to determine whether the filling of vesicles with the transmitter was altered. The quantal size and shape characteristics of amperometric events were identical for all mouse lines, suggesting that overexpression of WT or mutant alpha-syn did not affect vesicular transmitter accumulation or the kinetics of vesicle fusion. The frequency and number of exocytotic events per stimulus, however, was lower for both WT and A30P alpha-syn-overexpressing cells. The alpha-syn-overexpressing cells exhibited reduced depression of evoked release in response to repeated stimuli, consistent with a smaller population of readily releasable vesicles. We conclude that alpha-syn overexpression inhibits a vesicle "priming" step, after secretory vesicle trafficking to "docking" sites but before calcium-dependent vesicle membrane fusion.

Alpha-synuclein overexpression increases cytosolic catecholamine concentration.

Dysregulation of dopamine homeostasis and elevation of the cytosolic level of the transmitter have been suggested to underlie the vulnerability of catecholaminergic neurons in Parkinson's disease. Because several known mutations in alpha-synuclein or overexpression of the wild-type (WT) protein causes familial forms of Parkinson's disease, we investigated possible links between alpha-synuclein pathogenesis and dopamine homeostasis. Chromaffin cells isolated from transgenic mice that overexpress A30P alpha-synuclein displayed significantly increased cytosolic catecholamine levels as measured by intracellular patch electrochemistry, whereas cells overexpressing the WT protein and those from knock-out animals were not different from controls. Likewise, catechol concentrations were higher in L-DOPA-treated PC12 cells overexpressing A30P or A53T compared with those expressing WT alpha-synuclein, although the ability of cells to maintain a low cytosolic dopamine level after L-DOPA challenge was markedly inhibited by either protein. We also found that incubation with low-micromolar concentrations of WT, A30P, or A53T alpha-synuclein inhibited ATP-dependent maintenance of pH gradients in isolated chromaffin vesicles and that the WT protein was significantly less potent in inducing the proton leakage. In summary, we demonstrate that overexpression of different types of alpha-synuclein disrupts vesicular pH and leads to a marked increase in the levels of cytosolic catechol species, an effect that may in turn trigger cellular oxyradical damage. Although multiple molecular mechanisms may be responsible for the perturbation of cytosolic catecholamine homeostasis, this study provides critical evidence about how alpha-synuclein might exert its cytotoxicity and selectively damage catecholaminergic cells.

A glial cell line-derived neurotrophic factor (GDNF):tetanus toxin fragment C protein conjugate improves delivery of GDNF to spinal cord motor neurons in mice.

Glial cell line-derived neurotrophic factor (GDNF) has shown robust neuroprotective and neuroreparative activities in various animal models of Parkinson's Disease or amyotrophic lateral sclerosis (ALS). The successful use of GDNF as a therapeutic in humans, however, appears to have been hindered by its poor bioavailability to target neurons in the central nervous system (CNS). To improve delivery of exogenous GDNF protein to CNS motor neurons, we employed chemical conjugation techniques to link recombinant human GDNF to the neuronal binding fragment of tetanus toxin (tetanus toxin fragment C, or TTC). The predominant species present in the purified conjugate sample, GDNF:TTC, had a molecular weight of approximately 80 kDa as determined by non-reducing SDS-PAGE. Like GDNF, addition of GDNF:TTC to culture media of neuroblastoma cells expressing GFRalpha-1/c-RET produced a dose-dependent increase in cellular phospho-c-RET levels. Treatment of cultured midbrain dopaminergic neurons with either GDNF or the conjugate similarly promoted both DA neuron survival and neurite outgrowth. However, in contrast to mice treated with GDNF by intramuscular injection, mice receiving GDNF:TTC revealed intense GDNF immunostaining associated with spinal cord motor neurons in fixed tissue sections. That GDNF:TTC provided neuroprotection of axotomized motor neurons in neonatal rats further revealed that the conjugate retained its GDNF activity in vivo. These results indicate that TTC can serve as a non-viral vehicle to substantially improve the delivery of functionally active growth factors to motor neurons in the mammalian CNS.

Methamphetamine-induced degeneration of dopaminergic neurons involves autophagy and upregulation of dopamine synthesis.

Methamphetamine (METH) selectively injures the neurites of dopamine (DA) neurons, generally without inducing cell death. It has been proposed that METH-induced redistribution of DA from the vesicular storage pool to the cytoplasm, where DA can oxidize to produce quinones and additional reactive oxygen species, may account for this selective neurotoxicity. To test this hypothesis, we used mice heterozygous (+/-) or homozygous (-/-) for the brain vesicular monoamine uptake transporter VMAT2, which mediates the accumulation of cytosolic DA into synaptic vesicles. In postnatal ventral midbrain neuronal cultures derived from these mice, METH-induced degeneration of DA neurites and accumulation of oxyradicals, including metabolites of oxidized DA, varied inversely with VMAT2 expression. METH administration also promoted the synthesis of DA via upregulation of tyrosine hydroxylase activity, resulting in an elevation of cytosolic DA even in the absence of vesicular sequestration. Electron microscopy and fluorescent labeling confirmed that METH promoted the formation of autophagic granules, particularly in neuronal varicosities and, ultimately, within cell bodies of dopaminergic neurons. Therefore, we propose that METH neurotoxicity results from the induction of a specific cellular pathway that is activated when DA cannot be effectively sequestered in synaptic vesicles, thereby producing oxyradical stress, autophagy, and neurite degeneration.

Multiple sclerosis in US minority populations: Clinical practice insights.

The heterogeneity of multiple sclerosis (MS) characteristics among various ethnic minority populations is a topic of recent interest. However, these populations are consistently underrepresented in clinical trials, leading to limited data on the effectiveness of treatments in these groups of patients and lack of an evidence-based approach to treatment. In order to achieve optimal disease management in the ethnic minority MS populations, a better understanding of the regional, socioeconomic, and cultural influences that result in underrepresentation of these groups in clinical trials is needed. Furthermore, it would be beneficial to identify the genetic factors that influence disease disparity in these minority populations. Suggestions for the identification and implementation of best practices for fostering the trust of ethnic minority patients with MS and enhancing their participation in clinical trials are offered.

Interplay between cytosolic dopamine, calcium, and alpha-synuclein causes selective death of substantia nigra neurons.

The basis for selective death of specific neuronal populations in neurodegenerative diseases remains unclear. Parkinson's disease (PD) is a synucleinopathy characterized by a preferential loss of dopaminergic neurons in the substantia nigra (SN), whereas neurons of the ventral tegmental area (VTA) are spared. Using intracellular patch electrochemistry to directly measure cytosolic dopamine (DA(cyt)) in cultured midbrain neurons, we confirm that elevated DA(cyt) and its metabolites are neurotoxic and that genetic and pharmacological interventions that decrease DA(cyt) provide neuroprotection. L-DOPA increased DA(cyt) in SN neurons to levels 2- to 3-fold higher than in VTA neurons, a response dependent on dihydropyridine-sensitive Ca2+ channels, resulting in greater susceptibility of SN neurons to L-DOPA-induced neurotoxicity. DA(cyt) was not altered by alpha-synuclein deletion, although dopaminergic neurons lacking alpha-synuclein were resistant to L-DOPA-induced cell death. Thus, an interaction between Ca2+, DA(cyt), and alpha-synuclein may underlie the susceptibility of SN neurons in PD, suggesting multiple therapeutic targets.

Resistance of alpha -synuclein null mice to the parkinsonian neurotoxin MPTP.

Parkinson's disease (PD) is most commonly a sporadic illness, and is characterized by degeneration of substantia nigra dopamine (DA) neurons and abnormal cytoplasmic aggregates of alpha-synuclein. Rarely, PD may be caused by missense mutations in alpha-synuclein. MPTP, a neurotoxin that inhibits mitochondrial complex I, is a prototype for an environmental cause of PD because it produces a pattern of DA neurodegeneration that closely resembles the neuropathology of PD. Here we show that alpha-synuclein null mice display striking resistance to MPTP-induced degeneration of DA neurons and DA release, and this resistance appears to result from an inability of the toxin to inhibit complex I. Contrary to predictions from in vitro data, this resistance is not due to abnormalities of the DA transporter, which appears to function normally in alpha-synuclein null mice. Our results suggest that some genetic and environmental factors that increase susceptibility to PD may interact with a common molecular pathway, and represent the first demonstration that normal alpha-synuclein function may be important to DA neuron viability.