Profound cardiac sympathetic denervation occurs in Parkinson disease

Clinical laboratory evaluation of autoimmune autonomic ganglionopathy: Preliminary observations

Several forms of chronic autonomic failure manifest as neurogenic orthostatic hypotension, including autoimmune autonomic ganglionopathy (AAG) and pure autonomic failure (PAF). AAG and PAF are thought to differ in pathogenesis, AAG reflecting decreased ganglionic neurotransmission due to circulating antibodies to the neuronal nicotinic receptor and PAF being a Lewy body disease with prominent loss of sympathetic noradrenergic nerves. AAG therefore would be expected to differ from PAF in terms of clinical laboratory findings indicating post-ganglionic noradrenergic denervation. Both diseases are rare. Here we report preliminary observations about clinical physiologic, neuropharmacologic, neurochemical, and neuroimaging data that seem to fit with the hypothesized pathogenetic difference between AAG and PAF. Patients with either condition have evidence of baroreflex-sympathoneural and baroreflex-cardiovagal failure. Both disorders feature low plasma levels of catecholamines during supine rest, but plasma levels of the other endogenous catechols, dihydroxyphenylalanine (DOPA), dihydroxyphenylacetic acid (DOPAC), and dihydroxyphenylglycol (DHPG), seem to be lower in PAF than in AAG, probably reflecting decreased norepinephrine synthesis and turnover in PAF, due to diffuse sympathetic noradrenergic denervation. PAF entails cardiac sympathetic denervation, whereas cardiac sympathetic neuroimaging by thoracic 6-[(18)F]fluorodopamine scanning indicates intact myocardial sympathetic innervation in AAG.

Biomarkers to detect central dopamine deficiency and distinguish Parkinson disease from multiple system atrophy

OBJECTIVE

Biomarkers are increasingly important to diagnose and test treatments of neurodegenerative diseases such as Parkinson disease (PD). This study compared neuroimaging, neurochemical, and olfactory potential biomarkers to detect central dopamine (DA) deficiency and distinguish PD from multiple system atrophy (MSA).

METHODS

In 77 PD, 57 MSA, and 87 control subjects, radioactivity concentrations in the putamen (PUT), caudate (CAU), occipital cortex (OCC), and substantia nigra (SN) were measured 2h after 6-[18F]fluorodopa injection, septal myocardial radioactivity measured 8min after 6-[18F]fluorodopamine injection, CSF and plasma catechols assayed, or olfaction tested (University of Pennsylvania Smell Identification Test (UPSIT)). Receiver operating characteristic curves were constructed, showing test sensitivities at given specificities.

RESULTS

PUT:OCC, CAU:OCC, and SN:OCC ratios of 6-[18F]fluorodopa-derived radioactivity were similarly low in PD and MSA (p<0.0001, p<0.0001, p=0.003 compared to controls), as were CSF dihydroxyphenylacetic acid (DOPAC) and DOPA concentrations (p<0.0001, each). PUT:SN and PUT:CAU ratios were lower in PD than in MSA (p=0.004; p=0.005). CSF DOPAC correlated positively with PUT:OCC ratios (r=0.61, p<0.0001). Myocardial 6-[18F]fluorodopamine-derived radioactivity distinguished PD from MSA (83% sensitivity at 80% specificity, 100% sensitivity among patients with neurogenic orthostatic hypotension). Only PD patients were anosmic; only MSA patients had normal olfaction (61% sensitivity at 80% specificity).

CONCLUSIONS

PD and MSA feature low PUT:OCC ratios of 6-[18F]fluorodopa-derived radioactivity and low CSF DOPAC and DOPA concentrations, cross-validating the neuroimaging and neurochemical approaches but not distinguishing the diseases. PUT:SN and PUT:CAU ratios of 6-[18F]fluorodopa-derived radioactivity, cardiac 6-[18F]fluorodopamine-derived radioactivity, and olfactory testing separate PD from MSA.

Frequency and characteristics of extremely low accumulation of 123I-metaiodobenzylguanidine (MIBG) in patients with and without cardiovascular diseases

OBJECTIVE

Very low accumulation of 123I-metaiodobenzylguanidine (LoMIBG) in the human heart has been reported. This study assessed the frequency and characteristics of LoMIBG in the human heart.

METHODS

A total of 2212 patients (male/female ratio 1442/770, mean age 64 +/- 12 years) who underwent MIBG imaging were included. LoMIBG was defined as an initial heart-to-mediastinum (H/M) ratio of less than 1.4.

RESULTS

Of the 114 patients with LoMIBG, 2 patients were excluded because of taking imipramine. Patients with LoMIBG were older than those without LoMIBG (P < 0.0001). The main diagnosis and the number of patients with each disease were as follows: 28 of 410 coronary artery disease patients, 13 of 371 vasospastic angina patients, 3 of 86 various arrhythmias patients, 4 of 23 valvular heart disease patients, 9 of 101 dilated cardiomyopathy patients, 13 of 512 essential hypertension patients, 2 of 20 hypertrophic cardiomyopathy patients, 24 of 511 subjects without any definite disease (control), and 16 of 176 patients with miscellaneous diseases. When compared with patients without LoMIBG in each cardiovascular disease, LoMIBG patients had left ventricular function and frequency similar to critically ill patients. In the control group, the subjects with LoMIBG were significantly older (P < 0.0001) and had significantly higher HF (P < 0.03) and lower LF/HF (P < 0.001) than those without LoMIBG. In addition, the incidence of LoMIBG was significantly elevated in the elderly (P < 0.002).

CONCLUSIONS

LoMIBG occurred in patients both with various diseases and without obvious diseases. Aging may be one of the mechanisms contributing to LoMIBG, especially in patients without obvious diseases.

A critical reappraisal of current staging of Lewy-related pathology in human brain

Sporadic Parkinson disease (sPD) or brainstem-predominant type of Lewy body (LB) disease, and dementia with Lewy bodies (DLB), the two most frequent alpha-synucleinopathies, are progressive multisystem neurodegenerative disorders with widespread occurrence of alpha-synuclein (AS) deposits in the central, peripheral, and autonomic nervous system. For both LB-related disorders, staging/classification systems based on semiquantitative assessment of the distribution and progression pattern of Lewy-related/AS pathology are used that are considered to be linked to clinical dysfunctions. In PD, a six-stage system (Braak) has been suggested to indicate a predictable sequence of lesions with ascending progression from medullary and olfactory nuclei to the cortex, the first two presymptomatic stages being related to incidental LB disease, stages 3 and 4 with motor symptoms, and the last two (cortical) stages may be frequently associated with cognitive impairment. DLB, according to consensus pathologic guidelines, by semiquantitative scoring of AS pathology (LB density and distribution) in specific brain regions, is distinguished into three phenotypes (brainstem, transitional/limbic, and diffuse neocortical), also considering concomitant Alzheimer-related pathology. Retrospective clinico-pathologic studies, although largely confirming the staging system, particularly for younger onset PD with long duration, have shown that between 6.3 and 43% of the cases did not follow the proposed caudo-rostral progression pattern of AS pathology. There was sparing of medullary nuclei in 7-8.3% of clinically manifested PD cases with AS inclusions in midbrain and cortex corresponding to Braak stages 4 and 5, whereas mild parkinsonian symptoms were already observed in stages 2 and 3. There is considerable clinical and pathologic overlap between PD (with or without dementia) and DLB, corresponding to Braak LB stages 5 and 6, both frequently associated with variable Alzheimer-type pathology. Dementia often does not correlate with progressed stages of LB pathology, but may also be related to concomitant Alzheimer lesions or mixed pathologies. There is no relationship between Braak LB stage and the clinical severity of PD, and the predictive validity of this concept is doubtful, since large unselected, retrospective autopsy series in 30-55% of elderly subjects with widespread AS/Lewy-related pathology (Braak stages 5 and 6) reported no definite neuropsychiatric symptoms, suggesting considerable cerebral compensatory mechanisms. Applying the original criteria to large dementia samples, 49% of positive cases were not classifiable. Therefore, modified criteria for the categorization of Lewy-related pathology were proposed for patients with a history of dementia. The causes and molecular basis of the not infrequent deviations from the current staging schemes of AS pathology in PD and DLB, its relation to the onset of classical parkinsonian symptoms and for the lack of definite clinical deficits despite widespread AS pathology in the nervous system remain to be elucidated.

Reduced striatal tyrosine hydroxylase in incidental Lewy body disease

Incidental Lewy body disease (ILBD) is the term used when Lewy bodies are found in the nervous system of subjects without clinically documented parkinsonism or dementia. The prevalence of ILBD in the elderly population has been estimated at between 3.8 and 30%, depending on subject age and anatomical site of sampling. It has been speculated that ILBD represents the preclinical stage of Parkinson's disease (PD) and/or dementia with Lewy bodies (DLB). Studies of ILBD could potentially identify early diagnostic signs of these disorders. At present, however, it is impossible to know whether ILBD is a precursor to PD or DLB or is just a benign finding of normal aging. We hypothesized that, if ILBD represents an early stage of PD or DLB, it should be associated with depletion of striatal dopaminergic markers. Eleven subjects with ILBD and 27 control subjects were studied. The ILBD subjects ranged in age from 74 to 96 years (mean 86.5) while the control subjects' age ranged from 75 to 102 years (mean 86.7). Controls and subjects did not differ in terms of age, postmortem interval, gender distribution, medical history conditions, brain weight, neuritic plaque density or Braak neurofibrillary stage. Quantitative ELISA measurement of striatal tyrosine hydroxylase (TH), the principal enzyme for dopamine synthesis, showed a 49.8% (P = 0.01) reduction in ILBD cases, as compared with control cases. The finding suggests that ILBD is not a benign condition but is likely a precursor to PD and/or DLB.

Variability in the clinical expression of Parkinson's disease

Parkinsonism is a clinical syndrome characterized by bradykinesia, hypo-/akinesia, muscular rigidity, and resting tremor, mainly caused by Parkinson's disease (PD). Symptoms of PD are due to a progressive loss of nigral neurons causing striatal dopaminergic denervation. However, nigral degeneration is only a part of the underlying synucleinopathy, and clinical symptoms go far beyond motor parkinsonism. Olfactory disturbances, fatigue, pain, autonomic dysfunction, sleep fragmentation, depression, and dementia with or without psychosis are frequently seen. The variability in the expression of these signs and symptoms, as discussed in this paper, might be explained by the specific topographical sequence of the pathology, depending on the extent and progression of the degenerative process at defined sites. Better insight in the clinicopathological correlations of this disease may help to further develop early diagnosis and adequate therapeutic strategies.

[Clinical and pathological study on early diagnosis of Parkinson's disease and dementia with Lewy bodies]

[123I] Meta-iodobenzylguanidine (MIBG) myocardial scintigraphy has been used to evaluate postganglionic cardiac sympathetic innervation in heart diseases and some neurological disorders. To see clinical usefulness of MIBG myocardial scintigraphy to differentiate Parkinson's disease (PD) and dementia with Lewy bodies (DLB) from related movement disorders and Alzheimer disease (AD), we performed MIBG myocardial scintigraphy in patients with these disorders. Cardiac uptake of MIBG is specifically reduced in PD and DLB, and this imaging approach is a sensitive diagnostic tool that possibly differentiates PD and DLB from related movement disorders and AD. To see pathological basis of the reduced cardiac uptake of MIBG in Lewy body disease, we immunohistochemically examined cardiac tissues from patients with PD, DLB, related movement disorders and AD using antibodies against tyrosine hydroxylase (TH) and phosphorylated neurofilament (NF). Not only TH- but also NF-immunoreactive (ir) axons in the epicardial nerve fascicles were markedly decreased in Lewy body disease, namely cardiac sympathetic denervation, which accounts for the reduced cardiac uptake of MIBG in Lewy body disease. Patients with PD and DLB have Lewy bodies (LBs) in the nervous system, whereas patients with multiple system atrophy (MSA), progressive supranuclear palsy, corticobasal degeneration, parkin-associated PD and AD have no LBs in the nervous system. Even in patients with MSA, cardiac sympathetic denervation was associated with the presence of LBs. Therefore, cardiac sympathetic denervation is closely related to the presence of LBs in a wide range of neurodegenerative processes. Taken together, we conclude that the reduced cardiac uptake of MIBG is a potential biomarker for the presence of LBs. Because alpha-synuclein is one of the key molecules in the pathogenesis of PD, we further investigate how alpha-synuclein aggregates are involved in degeneration of the cardiac sympathetic nerve in PD. We immunohistochemically examined cardiac tissues from patients with incidental Lewy body disease (ILBD) and PD using antibodies against TH and phosphorylated alpha-synuclein. We found that (1) alpha-synuclein aggregates in the epicardial nerve fascicles, namely the distal axons of the cardiac sympathetic nerve, were much more abundant in ILBD with preserved TH-ir axons than in ILBD with decreased TH-ir axons and PD; (2) alpha-synuclein aggregates in the epicardial nerve fascicles were closely related to the disappearance of TH-ir axons; (3) in ILBD with preserved TH-ir axons, alpha-synuclein aggregates were consistently more abundant in the epicardial nerve fascicles than in the paravertebral sympathetic ganglia (pSG); and (4) this distal-dominant accumulation of alpha-synuclein aggregates was reversed in ILBD with decreased TH-ir axons and PD, which both showed decreased or depleted TH-ir axons but more abundant alpha-synuclein aggregates in the pSG. These findings indicate that accumulation of alpha-synuclein aggregates in the distal axons of the cardiac sympathetic nervous system precedes that of neuronal somata or neurites in the pSG and that heralds centripetal degeneration of the cardiac sympathetic nerve in PD. This chronological and dynamic relationship between alpha-synuclein aggregates and distal-dominant degeneration of the cardiac sympathetic nervous system may represent the pathological mechanism underlying a common degenerative process in PD.

Myocardial nerve fibers are preserved in MPTP-treated mice, despite cardiac sympathetic dysfunction

Recently, we reported a profound depletion of cardiac sympathetic nerve fibers in Parkinson's disease (PD). This cardiac sympathetic denervation is a characteristic hallmark of PD. Cardiac sympathetic dysfunction was also observed in 1-methyl-4-phenyl-1,2,3,6-tetrahydroxypyridine (MPTP)-treated mice, a model of PD. Although binding assay showed a decreased density of norepinephrine transporter (NET) in the hearts of the mice, their histopathological alterations have not been demonstrated. In this study, we investigated hearts of MPTP-treated mice with immunohistochemical method and Western blot analyses. MPTP-treated mice showed significant decreases in the contents of cardiac noradrenaline and dopamine, suggesting the sympathetic dysfunction. Synaptophysin-, tyrosine hydroxylase- or NET-immunoreactive nerve fibers were abundant in the hearts of control mice and MPTP-treated mice, without apparent differences between the two groups. Western blot analyses also showed no difference in the amounts of these proteins. Myocardial nerve fibers were well preserved in MPTP-treated mice, despite apparent cardiac sympathetic dysfunction.

Impaired cardiovascular autonomic function in Parkinson's disease with visual hallucinations

We assessed the relations of visual hallucinations (VH) to cardiovascular autonomic dysfunction in patients with Parkinson's disease (PD). The subjects were 37 patients without VH (VH(-)) and 31 with VH (VH(+)). Autonomic function was evaluated on the basis of cardiac 123-radioiodinated metaiodobenzylguanidine (123I-MIBG) uptake and hemodynamic testing with Valsalva maneuver. Systolic blood pressure (SBP) and plasma norepinephrine concentrations (NE) were measured by tilt-table testing. 123I-MIBG uptake was lower in VH(+) than VH(-). Hemodynamic studies showed that VH(-) had only cardiac sympathetic and parasympathetic dysfunction, while VH(+) additionally had reduced vasomotor sympathetic functions. The fall in SBP during tilt-table testing was greater in VH(+) than VH(-). NE and its difference in the supine and upright positions were decreased in VH(+). We conclude that cardiac and vasomotor sympathetic dysfunction is more severe in VH(+) than in VH(-). Severe dysfunction in PD with VH is probably attributed to Lewy-body lesions or neuronal loss in sympathetic ganglia, the central autonomic system, or both.

Lewy body variant of Alzheimer's disease or cerebral type Lewy body disease? Two autopsy cases of presenile onset with minimal involvement of the brainstem

Lewy bodies (LB) usually extend from the brainstem to the cerebrum in patients with Parkinson's disease. However, whether the patterns of progression of LB and neuronal loss in Parkinson's disease are identical to those in other Lewy body diseases (LBD) remains unclear. In addition, pathological data on the autonomic nervous system involvement in LBD are limited. We present here the clinicopathological characteristics of two autopsy cases with both Alzheimer's disease and dementia with Lewy bodies (DLB), possibly diagnosed as having Lewy body variant of Alzheimer's disease (LBV/AD). Our patients presented clinically with dementia without parkinsonism. Histopathologically, phosphorylated alpha-synuclein-positive LB and Lewy neurites were abundant in the limbic system, especially in the amygdala, and to a lesser degree, in the neocortex, including the primary motor cortex. The amygdala was also most severely affected by neuronal loss, and the other limbic areas and neocortex were affected to a lesser degree. Despite the existence of a small number of LB and many Lewy neurites, neurons in the brainstem nuclei were relatively well preserved. The Braak stages of concurrent neurofibrillary changes and senile plaques were stage V and C, respectively, in both cases. Tyrosine hydroxylase-positive nerve fibers were relatively well spared in one case examined compared with Parkinson's disease cases. Furthermore, many Lewy neurites immunopositive for phosphorylated a-synuclein were found in the nerve fascicles of the epicardium in one case examined and in Parkinson's disease cases to a lesser degree. These findings suggest that: (i) in at least some LBV/AD cases, the amygdala develops neuronal loss and Lewy-related pathology prior to the brainstem nuclei; and (ii) the depletion of nerves in the heart tissue of LBV/AD is not necessarily complete despite the development of Lewy-related pathology.

Degeneration of cardiac sympathetic nerve begins in the early disease process of Parkinson's disease

Decreased cardiac uptake of meta-iodobenzylguanidine (MIBG) on [(123)I] MIBG myocardial scintigraphy has been reported in the early stages of Parkinson's disease (PD), which suggests involvement of the cardiac sympathetic nerve in the early disease process of PD. For confirmation, we immunohistochemically examined cardiac tissue, sympathetic ganglia and medulla oblongata of 20 patients with incidental Lewy body disease (ILBD), which is thought to be a presymptomatic stage of PD, and 10 control subjects, using antibodies against tyrosine hydroxylase (TH) and neurofilament (NF). Immunoreactive nerve fibers of fascicles in the epicardium were well preserved in 10 of the 20 patients with ILBD and in the control subjects. In contrast, TH-immunoreactive nerve fibers had nearly disappeared in six subjects and were moderately decreased in four of the 20 patients with ILBD. Neuronal cell loss in the dorsal vagal nucleus and the sympathetic ganglia was not detectable in any of the ILBD patients examined. These findings suggest that degeneration of the cardiac sympathetic nerve begins in the early disease process of PD and that it occurs before neuronal cell loss in the dorsal vagal nucleus.

Degeneration of cardiac sympathetic nerve can occur in multiple system atrophy

Decreased cardiac uptake of meta-iodobenzylguanidine (MIBG) on [(123)I] MIBG myocardial scintigraphy, a sensitive biological marker for Parkinson's disease (PD), is related to cardiac sympathetic denervation in patients with PD. A slight decrease in cardiac uptake of MIBG has also been reported in some patients with multiple system atrophy (MSA). However, the pathophysiological mechanism accounting for the slight decrease in MIBG uptake in MSA remains to be elucidated. For confirmation, we examined cardiac tissue and sympathetic ganglia from patients with MSA. We immunohistochemically examined each specimen of 15 patients with MSA together with 10 control subjects using antibodies against tyrosine hydroxylase (TH) and neurofilament (NF). The number of TH-immunoreactive nerve fibers in the epicardium was preserved in 8 of 15 patients with MSA as well as in 10 control subjects. The number of TH-immunoreactive, but not of NF-immunoreactive nerve fibers in the epicardium was mildly or moderately decreased in six patients with MSA, of whom four showed a decrease of TH immunoreactivity in the neuronal somata in the sympathetic ganglia. Moreover, TH- and NF-immunoreactive nerve fibers almost entirely disappeared in the heart of one patient with MSA, in whom Lewy body pathology was present in the sympathetic ganglia. These findings suggest that mild degeneration of the cardiac sympathetic nerve can occur in MSA which is closely related to the pathological change of neurons in the sympathetic ganglia, accounting for the slight decrease in cardiac uptake of MIBG. Moreover, concurrent Lewy body pathology in the sympathetic ganglia might accelerate cardiac sympathetic denervation even in MSA.

Cardiovascular aspects of Parkinson disease

This chapter provides an update about cardiovascular aspects of Parkinson disease (PD), with the following topics: (1) Orthostatic hypotension (OH) as an early finding in PD; (2) neurocirculatory abnormalities in PD + OH independent of levodopa treatment; (3) cardiac and extracardiac noradrenergic denervation in PD + OH; (4) progressive loss of cardiac sympathetic innervation in PD without OH.

Clinical catecholamine neurochemistry: a legacy of Julius Axelrod

1. Discoveries, insights, and concepts that Julius Axelrod introduced about the disposition and metabolism of catecholamines provided the scientific basis and spurred the development of clinical catecholamine neurochemistry. 2. Here, we provide examples of this aspect of Axelrod's scientific legacy.

Alpha-synuclein pathology of the spinal and peripheral autonomic nervous system in neurologically unimpaired elderly subjects

Studies on cases with incidental Lewy body disease (ILBD) suggest that alpha-synuclein (alphaSN) pathology of Parkinson's disease (PD) starts in lower brainstem nuclei and in the olfactory bulb. However, medullary structures as the induction site of alphaSN pathology have been questioned as large parts of the nervous system, including the spinal cord and the peripheral autonomic nervous system (PANS), have not been examined in ILBD. Thus, the time course of PD lesions in the spinal cord or PANS in relation to medullary lesions remains unknown. We collected 98 post mortem cases with no reference to PD-associated symptoms on clinical records. alphaSN pathology was found in the central nervous system, including the spinal cord, and in the PANS in 17 (17.3%) cases. alphaSN pathology was encountered in autonomic nuclei of the thoracic spinal cord, brainstem and olfactory nerves in 17/17, in sacral parasympathetic nuclei in 15/16, in the myenteric plexus of oesophagus in 14/17, in sympathetic ganglia in 14/17, and in the vagus nerve in 12/16 cases. In addition to the thoracic lateral horns, a high number of alphaSN lesions was also found in non-autonomic spinal cord nuclei. Considering supraspinal structures our cases corresponded roughly to the recently described sequential order of alphaSN involvement in PD. Our study indicates, however, that the autonomic nuclei of the spinal cord and the PANS belong to the most constantly and earliest affected regions next to medullary structures and the olfactory nerves. A larger cohort of ILBD cases will be needed to pinpoint the precise induction site of alphaSN pathology among these structures.

Coronary vascular resistance in primary chronic autonomic failure

Patient groups with chronic autonomic failure and neuroimaging evidence of intact or absent cardiac sympathetic innervation had similar mean values for myocardial perfusion. Cardiac sympathetic outflow does not seem to contribute to coronary vascular resistance.

Orthostatic hypotension as an early finding in Parkinson's disease

Patients with Parkinson's disease (PD) commonly have clinically significant orthostatic hypotension (OH). In such patients PD+OH might be confused with multiple system atrophy (MSA), in which OH is a frequent finding, or with pure autonomic failure (PAF), if OH preceded clinical manifestations of the movement disorder. This study addressed whether OH can occur as an early finding in PD+OH. Historical data were analyzed from 35 patients with PD+OH evaluated at the NIH. OH was considered early if the patient had OH before, concurrent with, or starting within 1 year after onset of a symptomatic movement disorder. MSA was excluded by myocardial 6-[(18)F]fluorodopamine-derived radioactivity more than 2 standard deviations below the normal mean. Among the 35 PD+OH patients, 21 (60 %) had documentation of OH as an early finding. In 4 such patients, OH had preceded parkinsonism, and in 4 others, OH had dominated the early clinical picture, even after cessation of levodopa treatment for the movement disorder. In PD, OH can occur early in the disease, occasionally preceding or overshadowing the movement disorder.

Pathology of the sympathetic nervous system corresponding to the decreased cardiac uptake in 123I-metaiodobenzylguanidine (MIBG) scintigraphy in a patient with Parkinson disease

Decreased cardiac uptake in (123)I-metaiodobenzylguanidine (MIBG) scintigraphy has been adopted as one of the most reliable diagnostic tests for Parkinson disease (PD) in Japan. To investigate the morphological basis for this finding, we performed a detailed neuropathological study of the cardiac sympathetic nervous system of a 71-year-old autopsy-proven PD patient, who presented with a marked decrease in cardiac uptake of MIBG, just 1 year prior to death. We carefully examined the intermediolateral column at several levels of the thoracic spinal cord, the sympathetic trunk and ganglia, and the nerve plexus of the anterior wall of the left ventricle and compared the findings with those of five age-matched controls. We found that the cardiac plexus was more heavily involved than the sympathetic ganglia in this patient with PD. Our study may provide further evidence that the markedly decreased cardiac uptake of MIBG observed in PD cases represents preferential involvement of the cardiac sympathetic nerve plexus in this disorder.

Impaired myocardial 123I-metaiodobenzylguanidine uptake in Lewy body disease: Comparison between dementia with Lewy bodies and Parkinson's disease

BACKGROUND

Iodine-123-labeled metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy has been used to evaluate cardiac sympathetic denervation in Lewy body disease (LBD) including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Patients with LBD had marked reductions in cardiac MIBG accumulation, indicative of severe impairment of the cardiac sympathetic nervous systems. However, the differences in scintigraphy between DLB and PD have not been determined.

OBJECTIVE

To compare cardiac sympathetic function in early disease stage measured with 123I-MIBG scintigraphy between DLB and PD.

METHODS

123I-MIBG myocardial scintigraphy was performed in 22 patients with early-stage DLB, 41 patients with early idiopathic PD and 15 normal control subjects who were matched for age and disease duration. The heart-to-mediastinum (H/M) ratio was calculated.

RESULTS

123I-MIBG uptake of the myocardium was significantly lower in patients with early DLB than in controls. The mean value of H/M ratio in patients with DLB was significantly lower than those in patients with PD, independent of the Hoehn and Yahr stage.

CONCLUSIONS

Our findings suggest that cardiac sympathetic function in DLB is severely impaired even in the early disease stage.

Parkinson's disease: premotor clinico-pathological correlations

Parkinsonism is a clinical syndrome characterized by bradykinesia, hypo-/ akinesia, muscular rigidity, and resting tremor, mainly caused by Parkinson's disease (PD). Progressive loss of nigral neurons with Lewy bodies is considered an essential neuropathological feature. Recent studies, however, indicate that nigral degeneration is only a part of this synucleinopathy, and clinical symptoms go far beyond motor parkinsonism. Olfactory disturbances, autonomic dysfunction, pain, sleep fragmentation, depression, and dementia with or without psychosis are frequently seen. The variability in the expression of these signs and symptoms suggests multiple causes and/or pathogeneses within the present diagnostic disease entity. In this article, a recently proposed staging of PD-related brain pathology will be correlated with the various clinical expressions. It will be argued that the specific topographical sequence of the pathology, depending on the extent and progression of the degenerative process at defined sites, may explain the individually variable expression of this disease.

Hyperhidrosis in Parkinson's disease

We studied the sudomotor skin response (SSR) in patients with Parkinson's disease with and without symptomatic hyperhidrosis. The study was carried out in 13 patients who complained of excessive sweating and in 37 patients who did not have excessive sweating. Patients were matched for age, sex, degree of impairment, duration of the disease, and number and severity of autonomic disturbances. Excessive sweating involved mainly the face, head, and trunk. The SSR was recorded from the palm of the hands to electrical stimulation of the median nerve at the wrist. We analyzed onset latency, peak to peak amplitude, and waveform. Patients with hyperhidrosis had more often absent responses (chi(2) = 5.292; P = 0.021), their responses were of lower mean amplitude (analysis of variance [ANOVA]; F[2,101] = 11.678; P < 0.001), and they had a reduced number of responses with a predominantly negative component (chi(2) = 8.493; P = 0.004) than patients who did not complain of sweating disturbances. Our results indicate that excessive sweating in Parkinson's disease concurs with decreased activation of sweat glands in the palms of the hands and suggests that axial hyperhidrosis could be a compensatory phenomenon for reduced sympathetic function in the extremities.

Cardiac sympathetic denervation precedes neuronal loss in the sympathetic ganglia in Lewy body disease

Decreased cardiac uptake of meta-iodobenzylguanidine (MIBG) on [123I]MIBG myocardial scintigraphy has been reported in Parkinson's disease (PD) and dementia with Lewy bodies (DLB). We hypothesized that cardiac sympathetic denervation might account for the pathomechanism. To elucidate the extent, frequency and pattern of cardiac sympathetic nerve involvement in Lewy body disease and related neurodegenerative disorders, we immunohistochemically examined heart tissues from patients with PD (n=11), DLB (n=7), DLB with Alzheimer's disease (DLB/AD; n=4), multiple system atrophy (MSA; n=8), progressive supranuclear palsy (PSP; n=5), pure AD (n=10) and control subjects (n=5) together with sympathetic ganglia from patients with PD (n=5) and control subjects (n=4), using an antibody against tyrosine hydroxylase (TH). TH-immunoreactive nerve fibers in the hearts had almost entirely disappeared in nearly all the patients with PD, DLB and DLB/AD, whereas they were well preserved in all the patients with PSP and pure AD as well as in all except for one patient with MSA. In PD, neurons in the sympathetic ganglia were preserved in all except for one patient. Decreased cardiac uptake of MIBG in Lewy body disease reflects actual cardiac sympathetic denervation, which precedes the neuronal loss in the sympathetic ganglia.

Preserved cardiac sympathetic nerve accounts for normal cardiac uptake of MIBG in PARK2

We performed [123I] MIBG myocardial scintigraphy in two of three patients with PARK2 from unrelated families and examined the heart tissues from the three patients immunohistochemically using an antibody against tyrosine hydroxylase (TH) to see whether cardiac sympathetic nerve is involved. Cardiac uptake of MIBG was normal except for a slight decrease in the late phase in one of the patients. Postmortem examination revealed that TH-immunoreactive nerve fibers in the epicardium were well preserved in all three patients. The present study confirmed that cardiac sympathetic nerve is well preserved in PARK2 with a homozygous exon deletion, which accounts for normal cardiac uptake of MIBG. Moreover, normal cardiac uptake of MIBG might be of potential diagnostic value to indicate the absence of Lewy body pathology, even in patients with levodopa-responsive Parkinsonism, as in PARK2.