Objective: To detect early subclinical signs of autonomic dysfunction in the cardiovascular system and explore the mechanism of orthostatic hypotension (OH) in patients with multiple system atrophy (MSA). Methods: Eighteen male patients with possible MSA and 10 healthy men were recruited. The hemodynamic responses to head-up tilt and tilt-reversal were studied by an electrically-powered tilt table and a non-invasive cardiac output measurement (NICOM) system. Results: At supine, there was no signifi cant difference in blood pressure, heart rate (HR), stroke volume, cardiac output and total peripheral resistance between MSA patients and healthy controls. During tilting upright, OH developed in 5 MSA patients, with a 23.7±4.8 mmHg drop in systolic blood pressure. Patients with OH were older and exhibited higher scores in unifi ed Multiple System Atrophy Rating Scale part I than patients without OH. The stroke volume, cardiac output and total peripheral resistance did not differ between groups. The controls had the most signifi cant HR elevation (6.5±2.5 bpm) during tiltup, followed by patients without OH (2.8±1.6 bpm) and those with OH (-0.2±2.2 bpm). A similar trend of HR decrease was observed during return to supine posture. The process of tilt-reversal altered HR more signifi cantly than head-up tilt in controls (8.0±2.9 vs 6.5±2.5 bpm; P=0.031) and patients without OH (4.2±2.1 vs 2.8±1.6 bpm; P=0.032), but not in patients with OH (1.2±1.5 vs -0.2±2.2 bpm; P=0.380). Conclusions: The HR change during postural challenge showed signifi cant difference between MSA patients and healthy controls. Impaired HR responsiveness contributed to OH in MSA. Monitoring HR during the tilt table test may be a practical and useful method to detect early autonomic dysfunction in patients with MSA.

BACKGROUND AND PURPOSE: It is essential to develop a reliable predictive serum biomarker for Parkinson's disease (PD). The accumulation of alpha-synuclein (αSyn) and up-regulated expression of Rab35 participate in the etiology of PD. The purpose of this investigation was to determine whether the combined assessment of serum αSyn and Rab35 is a useful predictive biomarker for PD. METHODS: Serum levels of αSyn or Rab35 were determined in serum samples from 59 sporadic PD patients, 19 progressive supranuclear palsy (PSP) patients, 20 multiple system atrophy (MSA) patients, and 60 normal controls (NC). Receiver operating characteristics (ROC) curves were calculated to determine the diagnostic accuracy of αSyn or/and Rab35 in discriminating PD patients from NC or atypical parkinsonian patients. RESULTS: The levels of αSyn and Rab35 were increased in PD patients. The serum level of Rab35 was positively correlated with that of αSyn in PD patients. Compared to analyzing αSyn or Rab35 alone, the combined analysis of αSyn and Rab35 produced a larger area under the ROC curve and performed better in discriminating PD patients from NC, MSA patients, or PSP patients. When age was dichotomized at 55, 60, 65, or 70 years, the combined assessment of αSyn and Rab35 for classifying PD was better in the group below the cutoff age than in the group above the cutoff age. CONCLUSIONS: Combined assessment of serum αSyn and Rab35 is a better biomarker for discriminating PD patients from NC or atypical parkinsonian patients, and is a useful predictive biomarker for younger sporadic PD patients.
alpha-Synuclein ; Humans ; Multiple System Atrophy ; Parkinson Disease ; ROC Curve ; Supranuclear Palsy, Progressive