Cardiovascular dysautonomia in de novo Parkinson’s disease without orthostatic hypotension

Background: Clinical symptoms of Parkinson’s disease (PD) include not only motor distress, but also autonomic dysfunction. Objective: To study the characteristics of subclinical autonomic nervous dysfunction in de novo PD without orthostatic hypotension (OH). Methods: Autonomic nervous function including cardiac sympathetic gain was evaluated on the basis of cardiac radioiodinated metaiodobenzylguanidine (MIBG) uptake, the response to the Valsalva maneuver, and spectral analyses of the RR interval and blood pressure in 20 patients with de novo PD without OH. Results: Decreased cardiac MIBG uptake was found even in patients with PD without OH. Hemodynamic studies using the Valsalva maneuver revealed that patients with PD without OH had preserved baroreceptor reflex sensitivity in phase II and phase IV. Blood pressures normally responded in early and late phase II, but not in phase IV. Blood pressure recovery time was slightly reduced in patients with PD without OH when compared with the value in controls. The low frequency component of the RR interval and systolic blood pressure and the ratio of RR‐LF to RR‐HF in de novo PD without OH were significantly reduced when compared with the control values, whereas the high frequency component of the RR interval did not differ significantly. Conclusion: These results show that latent cardiac and vasomotor sympathetic dysfunction but not parasympathetic dysfunction is already present in early stage de novo PD, even without orthostatic hypotension.     

123I‐metaiodobenzylguanidine scintigraphy in Parkinson's disease and related disorders

Autonomic dysfunction is common in Lewy body disorders (Parkinson's disease, Dementia with Lewy Bodies, Pure Autonomic Failure, and REM sleep disorder). The loss of post‐ganglionic myocardial sympathetic nerve fibers is a prominent feature of autonomic dysfunction in such disorders. ¹²³I‐metaiodobenzylguanidine (MIBG) scintigraphy that visualizes catecholaminergic terminals in vivo is a biomarker used to detect cardiac sympathetic degeneration. Abnormal MIBG uptake has been consistently reported in Lewy body disorders. Some studies agree in the notion that increasing bradykinesia is related with an incremental cardiac sympathetic denervation, whereas tremor is not closely linked to cardiac denervation. “Atypical” parkinsonian syndromes, including Multiple System Atrophy, Progressive Supranuclear Palsy, and others, show modest reductions of cardial MIBG uptake. MIBG scintigraphy is moderately sensitive and specific in differentiating Parkinson's disease from such syndromes. Conversely, its sensitivity and specificity might be better in cognitively impaired patients, helping differential diagnosis between Dementia with Lewy Bodies, and Alzheimer disease. Confounding factors (comorbidities, comedications) should be carefully controlled before analyzing MIBG scintigraphy. © 2009 Movement Disorder Society     

Abnormality of the left ventricular sympathetic nervous function assessed by I-123 metaiodobenzylguanidine imaging in pediatric patients with neurocardiogenic syncope

The purpose of this study was to assess the left ventricular sympathetic nervous system function in the patients with neurocardiogenic syncope (NCS) using I-123 metaiodobenzylguanidine (MIBG) imaging of the heart, and to compare the plasma noradrenaline (NA) and MIBG results of tilt positive and tilt negative patients following a head-up tilt test (HUT). The study included 30 patients. Their physical and laboratory examinations did not show a pathology that may be the cause of their syncope. HUT test was positive in 13 patients and negative in 17 patients. Plasma NA concentrations were higher in the HUT positive than the HUT negative group at the beginning and at the 10th minute of the test. Specific I-123 MIBG uptake assessed as the cardiac to mediastinal activity ratio in the delayed image was significantly higher in HUT positive group. The higher levels of MIBG uptake and plasma NA observed in HUT positive patients may reflect the greater capacity of NA storage in cardiac adrenergic neuronal tissue in patients with NCS. The results of this study support the critical role of autonomic nervous system in the pathophysiology of NCS and the excessive sympathetic nervous stimulation as the trigger of paradox reflex.     

The vial kit formulation for preparation of no‐carrier‐added 131I‐MIBG

We have developed a new set of lyophilized kits, composed of 3 different kits, for the instant preparation of no‐carrier‐added ¹³¹I‐MIBG in the clinic. We here discussed the formulation of the kits, optimization of radiolabelling, quality control of radiolabeled ¹³¹I‐MIBG, and studies of animal biodistribution. The no‐carrier‐added (nca) ¹³¹I‐MIBG injection could be prepared within 30 minutes in the clinic with the help of the lyophilized kits. The radiochemical purity and specific activity (SA) could achieve above 98% and 6700 MBq/mg, respectively.     

肥厚性心肌病患者201Tl和123I-MIBG心肌SPECT显像

目的：探讨肥厚性心肌病的肥厚心肌与非肥厚心肌交感神经活性。方法选择１８例肥厚性心肌病（ＨＣＭ）患和６例对照（Ｎ组）。根据超声心动图将ＨＣＭ组分为心尖部肥厚性心肌病（ＡＰＭ）５例，非对称性心室间隔肥厚性心肌病（ＡＳＨ）７例，弥漫性肥厚性心肌病（ＤＰＭ）６列。所有患均进行超声心动图（Ｍ型和Ｂ型）检查＾２０１Ｔｌ和＾１２３Ｉ－间碘苄胍（ＭＩＢＧ）显像。结果ＨＣＭ组＾１２３Ｉ－ＭＩＢＧ显像与Ｎ组相