Liquid chromatography with electrochemical detection (LC-ED) after batch alumina extraction has been the mainstay for assaying levels of catecholamines and related 3,4-dihydroxy compounds (catechols) as part of the clinical laboratory workup of patients with neurogenic orthostatic hypotension, especially in the setting of the autonomic synucleinopathies Parkinson disease with orthostatic hypotension (PD + OH), pure autonomic failure (PAF), and multiple system atrophy (MSA). Liquid chromatography with tandem mass spectrometry (LC-MS/MS) is faster and measures catechols and non-catechol metabolites simultaneously but has not yet been validated sufficiently against LC-ED or used to assess catechol vs. non-catechol neurochemical abnormalities in autonomic synucleinopathies. We measured plasma catechols by LC-MS/MS and LC-ED in patients with PAF, PD + OH, or MSA and healthy controls. Cardiac sympathetic neuroimaging by 18F-dopamine positron emission tomography (PET) was used to indicate myocardial norepinephrine (NE) content in the same subjects. Across 41 participants (12 PAF, 9 PD + OH, 10 MSA, 10 controls) individual values for plasma 3,4-dihydroxyphenylglycol (DHPG), NE, and 3,4-dihydroxyphenylalanine (DOPA) by LC-MS/MS correlated positively with values by LC-ED (r = 0.97, 0.98, and 1.00, p < 0.0001 each). The PAF group had low mean NE, DHPG, normetanephrine, 3-methoxy-4-hydroxyphenylglycol, epinephrine, and metanephrine compared to the PD + OH group, while cardiac PET did not separate the 2 groups. We therefore conclude that LC-MS/MS validly assays plasma catechols. Several catechol and non-catechol biomarkers of generalized catecholamine deficiency separate PAF from PD + OH but not PD + OH from MSA, while 18F-dopamine PET separates PAF and PD + OH from MSA but not PAF from PD + OH. Combining LC-MS/MS with cardiac sympathetic neuroimaging efficiently differentiates among these conditions.

Background:Severe putamen dopamine depletion in Parkinson disease (PD) has been attributed to nigrostriatal denervation; however, there are also functional abnormalities in extant terminals (the "sick-but-not-dead" phenomenon). Rates of intra-neuronal processes of synthesis, storage, and metabolism of dopamine complexly influence releasable dopamine stores but have not yet been systematically estimated. Methods:Post-mortem empirical data were available about putamen tissue contents of 7 reactants, including the autotoxic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL). We constructed kinetic models depicting reactions related to putamen dopamine content, the simplest model consisting of 7 reactions and the most complete model 18 reactions among 10 intra-neuronal reactants. We used the post-mortem data, in vivo results of 18F-DOPA positron emission tomography (PET), and the models to estimate rates of the intra-neuronal processes and rank their contributions to control-PD differences. Results:There was about a 98% decrease in putamen tissue dopamine in PD. The concentration ratio of DOPAL/DA was about 9 times control. Applying the simplest kinetic model, vesicular sequestration was estimated to be decreased by 98.5% (0.073 vs. 4.91 nmol/min). About 3-fold greater in vivo "washout" of putamen 18F-DOPA-derived radioactivity compared to controls also indicated attenuated vesicular storage in PD. According to the complete model, control-PD differences in intra-neuronal reaction rates were, in descending order, vesicular uptake ≈ vesicular leakage > exocytotic release ≈ neuronal reuptake > L-aromatic-amino-acid decarboxylase activity ≈ tyrosine hydroxylase activity > other reactions. Discussion:Empirical post-mortem and in vivo data and application of kinetic models provide convergent quantitative evidence for a substantial vesicular storage defect in residual dopaminergic terminals in PD, a potential target for disease-modifying treatment or prevention strategies. Trial Registration:None.

Introduction Parkinson's disease (PD), pure autonomic failure (PAF), and multiple system atrophy (MSA) feature intracellular deposition of alpha-synuclein and catecholamine deficiency in the putamen or heart. This retrospective, cross-sectional, observational study assessed relationships of cerebrospinal fluid alpha-synuclein seed amplification assay (CSF SAA) data with catecholamine deficiency indicated by positron emission tomography (PET). Methods In groups with PD, PAF, parkinsonian MSA (MSA-P), or cerebellar MSA (MSA-C) SAAs were conducted by Rocky Mountain Laboratories (RML) and Amprion, Inc. using different assay conditions. 18F-DOPA PET examined putamen dopaminergic innervation, and 18F-dopamine PET assessed cardiac noradrenergic innervation. Results CSF SAAs by both RML and Amprion separated PD or PAF from MSA. The Amprion assay detected type 1 seeding associated with Lewy body diseases (LBDs) in 22/24 (92%) PD patients and 15/16 (94%) PAF patients and type 2 seeding associated with MSA in 9/10 (90%) MSA-P and 3/4 (75%) MSA-C patients (p < 0.0001). All of 24 PD and all of 9 MSA-P patients had low putamen/occipital cortex ratios of 18F-DOPA-derived radioactivity, while 11/13 (85%) PAF patients and 4/4 (100%) MSA-C patients had normal ratios. Contingency analyses of CSF SAA and brain 18F-DOPA PET efficiently separated the 4 groups (p < 0.0001). Conclusion CSF SAAs and cardiac 18F-dopamine PET distinguish LBDs from MSA but not PAF from PD or MSA-P from MSA-C. 18F-DOPA PET separates PAF from PD and MSA-P from MSA-C. Combining biomarkers differentiates among these synucleinopathies.

Background:Menkes disease is an X-linked recessive disorder of human copper metabolism. Droxidopa is a synthetic amino acid effective in reversing neurogenic orthostatic hypotension and correcting neurochemical abnormalities in congenital absence of dopamine-beta-hydroxylase (DBH), a copper-dependent enzyme that influences autonomic function. Individuals with disorders associated with variants in the copper transport gene ATP7A may manifest symptoms of dysautonomia, due to deficient DBH activity. We aimed to evaluate the safety and efficacy of droxidopa for dysautonomia in adults with Menkes disease or with occipital horn syndrome (an ATP7A allelic variant). Methods:We conducted a phase 1/2a, randomised, double-blind, placebo-controlled, crossover trial at one academic medical centre in Columbus, OH, USA. We compared placebo versus droxidopa treatment in adults with Menkes disease or occipital horn syndrome who manifested symptoms of dysautonomia (including orthostatic hypotension). Participants were recruited by invitation, screened, and randomly assigned to receive droxidopa or placebo for 6 weeks (Arm 1). Following a 7-10 day washout period, participants received the opposite treatment for 6 weeks (Arm 2/Crossover treatment). An open-label dose titration was utilised in advance to determine each participant's maximally tolerated dose (100, 200, or 300 mg) of droxidopa. The primary outcome of this trial was safety and tolerability assessed at 6 weeks, as reflected in the type and incidence of adverse events in the droxidopa treatment versus placebo groups. This trial is registered with ClinicalTrials.gov, NCT04977388. Findings:Between July 12, 2021 and Oct 30, 2023, three male participants were enrolled: two individuals with Menkes disease (19 and 26 years old) and one individual with occipital horn syndrome (age 35). We found significant improvements in norepinephrine levels (P < 0.01) and in a critical parameter of orthostatic hypotension, diastolic blood pressure drop during tilt table testing, while receiving droxidopa (-8.6, 95% CI -15.5 to -1.7; P = 0.018). There was no substantial difference in adverse events between the droxidopa and placebo groups. Interpretation:In this early phase trial, droxidopa was well tolerated in adults with Menkes disease and occipital horn syndrome and was associated with correction of orthostatic hypotension. These preliminary findings suggest that droxidopa at doses adjusted for patient tolerance is likely to be efficacious for treatment of dysautonomia in adults with ATP7A-related disorders. Further research is required, including in younger individuals with these conditions. Funding:The Menkes Disease Foundation UK, Associazione Angeli Per La Vita, and the Abigail Wexner Research Institute at Nationwide Children's Hospital.

Background and Objectives The arterial baroreflex has sympathoneural and cardiovagal efferent limbs. Whether quantitative measures represent interchangeable indicators of a single physiological construct has been unclear. Moreover, the extent to which results agree in the synucleinopathies pure autonomic failure (PAF), Parkinson disease with or without orthostatic hypotension (PD + OH, PD No OH), and multiple system atrophy (MSA) remains incompletely understood. In a retrospective observational study we comprehensively assessed physiological and neurochemical biomarkers of arterial baroreflex function in these disorders. Methods Data for 10 baroreflex-sympathoneural and 6 baroreflex-cardiovagal indices were compared among 38 patients with PAF, 63 with PD + OH, 63 with PD No OH, and 72 with MSA, along with 44 controls with complete datasets. Results Indices of baroreflex-sympathoneural and baroreflex-cardiovagal function were only weakly correlated. Within the two domains, correlations across subjects were much stronger. Among sympathoneural measures, pressure recovery time after the Valsalva maneuver, the logarithm of the total baroreflex area, and the fractional orthostatic increment in plasma norepinephrine best distinguished patients with autonomic synucleinopathies from controls. Among cardiovagal measures, the Baroslope derived from Phase II of the Valsalva maneuver and the logarithms of low- and high-frequency heart rate variability during supine rest were the most informative. No baroreflex measure separated PAF from PD + OH or MSA. Conclusions Indices derived from blood pressure and interbeat interval responses during the Valsalva maneuver capture much of the physiologically meaningful variation in arterial baroreflex function and provide efficient assessment of the sympathoneural and cardiovagal limbs in autonomic synucleinopathies.

In the central Lewy body diseases (LBDs) Parkinson's disease and dementia with Lewy bodies (DLB), by the time parkinsonism or cognitive dysfunction manifests, substantial central neurodegeneration has already occurred. Biomarkers of preclinical disease are needed to test strategies that might delay the onset of symptomatic central LBDs and extend healthspan. The prospective, longitudinal PDRisk study asked whether cardiac sympathetic neuroimaging, cerebrospinal fluid catecholamine metabolites, cardiovascular physiological biomarkers, and alpha-synuclein seeding activity predict central LBDs in at-risk individuals. This review highlights and builds on several findings from this unique study. Some concepts induced from the present and previous data are: 1) Central LBDs can begin outside the brain ("body-first"), with early involvement of cardiac sympathetic nerves as evidenced by ¹⁸F-dopamine positron emission tomography (PET) and normal initial putamen dopaminergic innervation by ¹⁸F-DOPA PET. 2) DLB can follow a similar body-first progression pattern. 3) Body-first LBDs entail tri-phasic temporal sequences, corresponding conceptually to homeostasis, dyshomeostasis, and symptomatic disease, noted in the heart years before the striatum. 4) LBDs feature a vesicular storage defect in extant catecholaminergic terminals, exemplifying the "sick-but-not-dead" phenomenon. 5) There are multiple other functional abnormalities in residual catecholaminergic terminals in LBDs. 6) Based on computational modeling, disease-modifying treatments begun in the dyshomeostatic phase might delay the onset of symptomatic LBDs, compressing morbidity.

Fatigue, brain fog and post-exertional malaise are major features of post-infectious myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of severe acute respiratory syndrome coronavirus 2. To date, no specific neurotransmitter abnormalities have been found in either condition. We examined the possibility of central catecholaminergic involvement and clinical correlates in post-infectious myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of severe acute respiratory syndrome coronavirus 2 groups compared to healthy volunteers and, as positive controls, Parkinson's disease patients. In an observational, cross-sectional cohort study conducted at the National Institutes of Health Clinical Center we measured CSF levels of catecholamines and metabolites in the four groups and assessed correlations with neurobehavioral measures. CSF indices of the central Norepinephrine Pathway (norepinephrine + 3,4-dihydroxyphenylglycol + 3-methoxy-4-hydroxyphenylglycol) and Dopamine Pathway (dopamine + 3,4-dihydroxyphenylacetic acid + homovanillic acid) were measured and related to patient-recorded outcomes and physiological assessments. Mean values for Norepinephrine Pathway activity (in pmol/mL) were lower in the post-infectious myalgic encephalomyelitis/chronic fatigue syndrome, post-acute sequelae of severe acute respiratory syndrome coronavirus 2, and Parkinson's disease groups compared to the healthy volunteer cohort (post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (-15.9, 95% confidence interval [-26.1, -5.7], P = 0.0006); post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (-9.62, [-17.9, -1.4], P = 0.015); Parkinson's disease (-19.4, [-27.5, -11.3], P < 0.0001)). Post-acute sequelae of severe acute respiratory syndrome coronavirus 2 participants with post-exertional malaise had evidence of central noradrenergic deficiency compared to healthy volunteers (-18.3 [-31.3, -5.3], P = 0.0018). The post-infectious myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of severe acute respiratory syndrome coronavirus 2 groups did not differ from the healthy group in values for the Dopamine Pathway index. Across all participants, Norepinephrine Pathway activity correlated positively with handgrip duration and general health and negatively with fatigue. We conclude that post-infectious myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of severe acute respiratory syndrome coronavirus 2 feature a specific central neurotransmitter pattern involving noradrenergic but not dopaminergic deficiency. The noradrenergic abnormality is associated with major symptoms such as post-exertional malaise.

Depletion of putamen dopamine (DA) characterizes Parkinson's disease (PD) and precedes the onset of motor symptoms by years. Increasing evidence implicates impaired vesicular sequestration and attenuated detoxification of the toxic catecholaldehyde 3,4-dihydroxyphenylacetaldehyde (DOPAL) in disease pathogenesis. We applied a mechanistic kinetic model to examine how perturbations in dopamine handling from DOPAL-induced autotoxicity affect the timing and trajectory of symptomatic PD. Using an icon-based application we constructed a model of intraneuronal dopamine synthesis, vesicular storage, leakage, metabolism, aldehyde detoxification, delayed toxicity, and α-synuclein modification. Model behavior was evaluated by internal consistency and concordance with empirical cellular, animal, imaging, and postmortem neurochemical data. We examined predicted effects of genetic variants, acquired factors (e.g., stress, environmental exposures), and treatments on vesicular dopamine content across the lifespan. Without imposing a predefined disease curve, the model generated a triphasic trajectory of vesicular dopamine loss-homeostasis, dyshomeostasis, and symptomatic decline-from delayed DOPAL-mediated toxicity, with progressive impairment of vesicular sequestration and other intraneuronal processes. The model predicted that genetic decreases in vesicular uptake or aldehyde detoxification and increases in dopamine biosynthesis would shorten the time to the onset of symptomatic disease, whereas monoamine oxidase inhibition, levodopa, and antioxidant treatment applied early and in combination would be protective. Preclinical, multitarget interventions would delay or prevent crossing a symptomatic threshold within the modeled lifespan. Systems modeling across the lifespan predicts a triphasic decline in putamen dopamine stores in PD. The timing and combination of interventions may be decisive for delaying or preventing symptomatic disease.NEW & NOTEWORTHY We used kinetic modeling to predict the temporal course of putamen dopamine depletion across the lifespan in Parkinson's disease and predict effects of autotoxicity, genetics, environmental exposures, and possible treatments on the timing of the onset of symptomatic disease.

The autonomic synucleinopathy multiple system atrophy (MSA) can be difficult to distinguish clinically from Parkinson disease with orthostatic hypotension (PD+OH). 18F-Dopamine positron emission tomography separates these conditions based on cardiac noradrenergic deficiency in PD+OH and not in MSA but is available only at the NIH Clinical Center. 3,4-Dihydroxyphenylglycol (DHPG) is the main neuronal metabolite of norepinephrine. This retrospective observational study examined whether DHPG levels in cerebrospinal fluid (CSF) or plasma differentiate MSA from PD+OH. We reviewed CSF and plasma neurochemical data from all patients referred for evaluation at the NIH Clinical Center between 1995 and 2024 for chronic autonomic failure or parkinsonism. A concurrently studied comparison group included healthy volunteers or patients with orthostatic intolerance. CSF DHPG was decreased in MSA (N = 67, p < 0.0001) compared to the controls but also tended to be decreased in PD+OH (N = 31, p = 0.0776). Antecubital venous plasma DHPG was decreased in PD+OH (N = 47, p = 0.0064) but not in MSA. CSF/plasma concentration ratios of DHPG were lower in MSA than in PD+OH (p = 0.0005). Cardiac arteriovenous increments in plasma DHPG and cardiac norepinephrine spillovers were strikingly decreased in PD+OH (N = 6) and were lower than in MSA (N = 20, p < 0.0001 each). Combining cardiac arteriovenous increments in plasma DHPG with norepinephrine spillovers completely separated PD+OH from MSA. CSF/plasma ratios of DHPG, cardiac arteriovenous increments in plasma DHPG, and cardiac norepinephrine spillovers separate MSA from PD+OH. On the basis of our results we propose that biomarker combinations involving DHPG in biofluids may enable a clinical laboratory distinction of MSA from PD+OH.

Lewy body diseases (LBDs) feature profound myocardial depletion of the sympathetic neurotransmitter norepinephrine. In addition to sympathetic neuronal loss, the norepinephrine deficiency may reflect decreased vesicular sequestration of cytoplasmic catecholamines in dysfunctional but living nerve terminals. To evaluate intraneuronal vesicular storage in patients with LBDs, we retrospectively analyzed multitracer PET data using 18F-6-fluorodopamine (18F-DA, a sympathetic neuroimaging agent) and 11C-methylreboxetine (11C-MRB, a ligand for the cell membrane norepinephrine transporter). If there were a vesicular storage defect, then the decrease in 18F-DA-derived radioactivity would be greater than the decrease in 11C-MRB-derived radioactivity. Methods: Twenty-three patients with Parkinson disease or the Lewy body form of pure autonomic failure and 15 controls underwent 18F-DA dynamic scanning (9 frames; last frame, 10-min duration with midpoint at 25 min) and on a separate day underwent 11C-MRB PET for 45 min (dynamic for 30 min, then a static 15-min frame with midpoint at 38 min). Results: All patients in the LBD group had interventricular septal 18F-DA-derived radioactivity below the range of values in the control group (mean decrease, 75%; P < 0.0001). The LBD group also had a mean decrease of 37% in 11C-MRB-derived radioactivity from the control group in the static frame with midpoint at 38 min (P < 0.0001). At all time points after tracer administration, septal myocardial 18F-DA/11C-MRB ratios were lower in the LBD group (by 68% at 25 min; P < 0.0001). Conclusion: LBDs entail substantially decreased vesicular storage in cardiac sympathetic nerves. This abnormality has direct implications for disease-modifying treatment and prevention strategies, since extant but dysfunctional ("sick-but-not-dead") neurons may be salvageable.

This essay examines, in an evolutionary perspective, body systems outside the brain that use the catecholamines dopamine (DA), norepinephrine (NE), and epinephrine (EPI) as chemical messengers. Peripheral catecholamine systems represent three mechanisms by which the brain regulates the functions of body organs. DA serves as an autocrine-paracrine factor in the kidneys and splanchnic organs, NE is the neurotransmitter of the sympathetic noradrenergic system (SNS), and EPI is the main hormone secreted by adrenomedullary chromaffin cells. Comparative physiological data suggest that the DA autocrine-paracrine system emerged first, followed by noradrenergic nerve networks culminating in the SNS, with the hormonal sympathetic adrenergic system (SAS) appearing most recently. Examples are presented of the diverse ways these catecholamines have been used during evolution, although the ecological niches that conferred selective advantages remain uncertain. The discussion addresses catecholamine receptors, cotransmission, and interactions between catecholaminergic, neuroendocrine, and immune systems. In humans, the transition to bipedalism likely promoted SNS adaptations for orthostatic regulation of brain blood flow as well as for sodium homeostasis and temperature control. The roles of the SAS in organism-wide stress responses, distress, and sympathoadrenal imbalance in fainting are also considered. Concepts such as antagonistic pleiotropy, allostatic load, and autotoxicity are discussed in relation to aging-associated diseases that feature catecholaminergic neurodegeneration. Understanding the phylogeny of peripheral catecholamine systems may provide a foundation for Darwinian medicine.

Lewy body diseases (LBDs) such as Parkinson disease (PD) feature increased deposition of α-synuclein (α-syn) in cutaneous sympathetic noradrenergic nerves. The pathophysiologic significance of sympathetic intraneuronal α-syn is unclear. We reviewed data about immunoreactive α-syn, tyrosine hydroxylase (TH, a marker of catecholaminergic fibers), and the sympathetic neurotransmitter norepinephrine (NE) in skin biopsies from control participants and patients with PD, the related LBD pure autonomic failure (PAF), the non-LBD synucleinopathy multiple system atrophy (MSA), or neurologic postacute sequelae of severe acute respiratory syndrome coronavirus 2 (neuro-PASC). In a retrospective observational study, we reviewed data about α-syn-TH colocalization indexes and immunoreactive α-syn and TH signal intensities in arrector pili muscles, blood vessels, and sweat glands from neck skin biopsies and NE concentrations in simultaneously obtained thigh skin biopsies from participants studied at the NIH Clinical Center. LBD, MSA, and control group data were assessed by analyses of variance with the Tukey post hoc test for multiple comparisons. Similar analyses were performed for patients with PD or neuro-PASC vs control. Dermal α-syn-TH colocalization indexes and α-syn signal intensities from neck skin biopsies were examined in 18 controls (mean age 58 years, 50% female) and 53 LBD (66, 34%), 15 MSA (61, 33%), and 11 neuro-PASC (52, 82%) patients. The LBD group had higher α-syn-TH colocalization indexes than the controls (mean difference = 1.495, 95% CI 1.081-1.909, p < 0.0001) and increased α-syn signal intensities in all 3 skin constituents (arrector pili: mean difference = 2.743, 95% CI 1.608-3.879, p < 0.0001; blood vessels: mean difference = 2.157, 95% CI 1.095-3.219, p < 0.0001; sweat glands: mean difference = 4.136, 95% CI 1.704-6.567, p < 0.0001). The groups did not differ in either immunoreactive TH or NE. The neuro-PASC and PD groups had elevated α-syn-TH colocalization indexes compared with the controls, also with no group differences in immunoreactive TH or NE contents. LBDs and neuro-PASC entail increased α-syn-TH colocalization indexes in skin biopsies, without evidence of local denervation or noradrenergic deficiency. The results fail to support toxicity of intraneuronal α-syn in cutaneous sympathetic noradrenergic nerves in either LBDs or neuro-PASC. The neuro-PASC data raise the possibility of sympathetic intraneuronal α-syn deposition as part of postinfectious immune or inflammatory processes.

J.N. Langley coined the term "autonomic nervous system" (ANS) about a century ago, referring to the sympathetic, parasympathetic, and enteric nervous systems. Discoveries since then about neuroendocrine and neuroimmune systems and the coordinating role of the brain justify expansion of the ANS concept. This review conveys the integrative physiological perspective that a hierarchical brain network—the "central autonomic network" (CAN)—regulates the ANS, neuroendocrine, and neuroimmune systems. Embedded within the CAN are components of the Chrousos/Gold "stress system." Neuroendocrine facets of the extended autonomic system (EAS) include the sympathetic adrenergic system, in which epinephrine is the key effector, the hypothalamic-pituitary-adrenocortical axis, and the renin-angiotensin-aldosterone system. Immune/inflammatory systems include the cholinergic anti-inflammatory and catecholamine-related inflammasomal systems. Reciprocal influences among the four components of the EAS (6 combinations of interactions) set the stage for feedback loops that maintain homeostasis and for feed-forward alterations in input-output curves that underlie allostasis. The EAS concept provides a framework for generating testable hypotheses related to the pathophysiology and pathophysiology-based treatment of a wide variety of complex, multi-system disorders of regulation.

BACKGROUND:Cerebrospinal fluid (CSF) α-synuclein seeding activity (SSA) via a seed amplification assay might predict central Lewy body diseases (LBD) in at-risk individuals. OBJECTIVE:The aim was to assess CSF SSA in a prospective, longitudinal study. METHODS:Participants self-reported risk factors were genetics, olfactory dysfunction, dream enactment behavior, orthostatic intolerance, or hypotension; individuals who had ≥3 confirmed risk factors underwent CSF sampling and were followed for up to 7.5 years. Participants who developed a central LBD (LBD+) were compared to those who did not. Quadruplicate SSA areas under the curve (AUC) were averaged. RESULTS:Of 11 subjects with average AUCs above 500,000 units, 7 (64%) developed a central LBD compared to 1 of 20 (5%), with AUCs below the cutoff value (P = 0.0011 by log-rank test). Conversely, 7 of 8 (88%) LBD+ participants had elevated initial AUCs. CONCLUSIONS:Increased CSF SSA predicts central LBDs. Individuals who develop a central LBD have elevated initial SSA AUCs.

BACKGROUND AND OBJECTIVES:Lewy body diseases (LBDs) such as Parkinson disease (PD) feature increased deposition of α-synuclein (α-syn) in cutaneous sympathetic noradrenergic nerves. The pathophysiologic significance of sympathetic intraneuronal α-syn is unclear. We reviewed data about immunoreactive α-syn, tyrosine hydroxylase (TH, a marker of catecholaminergic fibers), and the sympathetic neurotransmitter norepinephrine (NE) in skin biopsies from control participants and patients with PD, the related LBD pure autonomic failure (PAF), the non-LBD synucleinopathy multiple system atrophy (MSA), or neurologic postacute sequelae of severe acute respiratory syndrome coronavirus 2 (neuro-PASC). METHODS:In a retrospective observational study, we reviewed data about α-syn-TH colocalization indexes and immunoreactive α-syn and TH signal intensities in arrector pili muscles, blood vessels, and sweat glands from neck skin biopsies and NE concentrations in simultaneously obtained thigh skin biopsies from participants studied at the NIH Clinical Center. LBD, MSA, and control group data were assessed by analyses of variance with the Tukey post hoc test for multiple comparisons. Similar analyses were performed for patients with PD or neuro-PASC vs control. RESULTS:Dermal α-syn-TH colocalization indexes and α-syn signal intensities from neck skin biopsies were examined in 18 controls (mean age 58 years, 50% female) and 53 LBD (66, 34%), 15 MSA (61, 33%), and 11 neuro-PASC (52, 82%) patients. The LBD group had higher α-syn-TH colocalization indexes than the controls (mean difference = 1.495, 95% CI 1.081-1.909, p < 0.0001) and increased α-syn signal intensities in all 3 skin constituents (arrector pili: mean difference = 2.743, 95% CI 1.608-3.879, p < 0.0001; blood vessels: mean difference = 2.157, 95% CI 1.095-3.219, p < 0.0001; sweat glands: mean difference = 4.136, 95% CI 1.704-6.567, p < 0.0001). The groups did not differ in either immunoreactive TH or NE. The neuro-PASC and PD groups had elevated α-syn-TH colocalization indexes compared with the controls, also with no group differences in immunoreactive TH or NE contents. DISCUSSION:LBDs and neuro-PASC entail increased α-syn-TH colocalization indexes in skin biopsies, without evidence of local denervation or noradrenergic deficiency. The results fail to support toxicity of intraneuronal α-syn in cutaneous sympathetic noradrenergic nerves in either LBDs or neuro-PASC. The neuro-PASC data raise the possibility of sympathetic intraneuronal α-syn deposition as part of postinfectious immune or inflammatory processes.

Menkes disease is an X-linked recessive condition characterized by seizures, failure to thrive, and rapid, progressive neurodegeneration beginning within weeks after birth. Death usually occurs by 3 years of age. The disorder is caused by genetic variants in ATP7A, an evolutionarily conserved copper transporter that is crucial for normal brain development. The mottled-brindled mouse recapitulates salient features of the human illness. Affected male mice typically die by 14 postnatal days. We evaluated a single-dose intravenous adeno-associated virus gene therapy approach to deliver working copies of a codon-optimized version of ATP7A to male mottled-brindled mice. In conjunction with subcutaneous injections of clinical-grade copper histidinate in the first month of life, 95% long-term survival was attained, which was correlated with improvements in serum and brain copper levels, brain neurochemical profiles, somatic growth, and neuromotor function. The notable results support a trial of this treatment combination in affected male newborns with Menkes disease.

Background:Pyridostigmine bromide is a short-acting carbamate acetylcholinesterase inhibitor that has been shown to acutely augment parasympathetic signaling in cardiovascular disease populations. Objective:This study was undertaken to characterize pharmacodynamics, safety, and tolerability of pyridostigmine during repeated dosing in patients with heart failure. Methods:A prospective ascending-dose, forced titration, double-blind Phase II randomized clinical trial was conducted to compare the effects of pyridostigmine bromide (15, 30, and 60 mg TID over 8 weeks) versus matching placebo on red blood cell (RBC) acetylcholinesterase activity, cholinergic side effects, and physiologic measures of parasympathetic heart rate modulation and sympathovagal balance in ambulatory patients with chronic systolic heart failure. Results:Fifty subjects were screened, and 33 eligible subjects were randomly assigned (mean age, 55 years; mean left ventricular ejection fraction, 23%). Pyridostigmine bromide significantly decreased RBC acetylcholinesterase activity (P < 0.02 vs placebo) and increased the frequency of participant-reported cholinergic excess symptoms (P < 0.001 vs placebo). Physiologic measures of parasympathetic heart rate modulation and sympathovagal balance did not differ between treatment groups. In the pyridostigmine bromide group, RBC acetylcholinesterase activity was not significantly associated with postexercise parasympathetic heart modulation. Conclusions:Pyridostigmine bromide administered over 8 weeks was associated with a significant reduction of RBC acetylcholinesterase activity and relatively mild symptoms of cholinergic excess, but changes in parasympathetic signaling in the sinoatrial node previously reported after acute administration were not observed. Further investigations are needed to delineate pharmacodynamic and pathobiological factors contributing to these findings. ClinicalTrials.gov identifier: NCT01415921.

Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and other synucleinopathies are characterized by the accumulation of abnormal, self-propagating aggregates of α-synuclein. RT-QuIC or seed amplification assays are currently showing unprecedented diagnostic sensitivities and specificities for synucleinopathies even in prodromal phases years in advance of the onset of Parkinsonian signs or dementia. However, commonly used α-synuclein seed amplification assays take ≥48 h to perform as applied to patients’ diagnostic biospecimens. Here, we report the development of a faster α-synuclein RT-QuIC assay that is as analytically sensitive as prior assays of this type, but can be completed in ≤12 h for brain, skin, and intestinal mucosa, with positive signals often arising in <5 h. CSF assays took a few hours longer. Our same-day α-synuclein RT-QuIC (sdRT-QuIC) assay should increase the practicality, cost-effectiveness, and throughput of measurements of pathological forms of α-synuclein for fundamental research, clinical diagnosis, and therapeutics development.