Low, Phillip A.

Abstract Background Therapeutic options for management of diabetic gastroparesis are limited. Failure to maintain upregulation of heme oxygenase ( HO 1) leads to loss of interstitial cells of Cajal and delayed gastric emptying ( GE ) in non‐obese diabetic mice. Our hypothesis was that hemin upregulation of HO 1 would restore normal GE in humans with gastroparesis. Aims To compare effects of hemin and placebo infusions on HO 1 activity and protein, GE , autonomic function, and gastrointestinal symptoms in diabetic gastroparesis. Methods In a single‐center, double‐blind, placebo‐controlled, randomized clinical trial, we compared intravenous hemin, prepared in albumin, or albumin alone (placebo) in 20 patients, aged 41 ± 5 ( SEM ) years with diabetic gastroparesis. After infusions on days 1, 3, and 7, weekly infusions were administered for 7 additional weeks. Assessments included blood tests for HO 1 protein and enzyme activity levels, GE with 13 C‐spirulina breath test, autonomic functions (baseline and end), and gastrointestinal symptoms every 2 weeks. Key Results Nine of 11 patients randomized to hemin completed all study procedures. Compared to placebo, hemin increased HO 1 protein on days 3 ( p = 0.0002) and 7 ( p = 0.008) and HO 1 activity on day 3 ( p = 0.0003) but not after. Gastric emptying, autonomic functions, and symptoms did not differ significantly in the hemin group relative to placebo. Conclusions & Inferences Hemin failed to sustain increased HO 1 levels beyond a week and did not improve GE or symptoms in diabetic gastroparesis. Further studies are necessary to ascertain whether more frequent hemin infusions or other drugs would have a more sustained effect on HO 1 and improve GE .

The objective of the present study was to evaluate the influence of posture on the responses of blood pressure (BP) and heart rate (HR) to the Valsalva manoeuvre (VM). Neurohumoral activation, as well as changes in intravascular and intracardiac volumes and pressures, are well known effects of orthostatic stress. These changes are likely to have significant effects on cardiovascular reflexes, such as the response to the VM. However, the influence of posture on the VM has not been intensively evaluated, except for a few studies involving small sex- and age-selected case series. We therefore investigated the effects of posture on the VM in a larger non-selected group of healthy control subjects. In 19 healthy volunteers (ten female/nine male; age range 20–72 years, mean age 43 years), two reproducible VMs (40 mmHg; 15 s) were performed after 10 min of supine rest, 10 min of sitting and 10 min of standing. HR and BP were monitored continuously. End-diastolic volume, total peripheral resistance and cardiac output were calculated at baseline for each position. We found that assuming an upright position resulted in increases in total peripheral resistance and HR, accompanied by decreases in end-diastolic volume and cardiac output. The fall in BP during early phase II and the BP overshoot during phase IV were clearly more pronounced with increasing orthostatic stress, whereas the rise in BP during late phase II remained unchanged; pulse pressure was more compressed during phase II, but higher during phase IV. The Valsalva ratio was not significantly affected, but baroreflex gain (calculated from early phase II) was significantly decreased in the upright position. While a reduced late phase II was observed on one occasion in each of the lying and sitting positions, three abnormal responses were observed during standing. We conclude that posture has a significant influence on BP responses to the VM, probably resulting from changes in the intrathoracic blood volume. Standing results in a lower rate of ‘flat-top’ responses, but also seems to reduce the specificity of this test. Sympathetic activation in the upright position seems to blunt baroreflexes, leading to similar HR responses in spite of larger changes in BP.

Abstract This retrospective study evaluated the frequencies of symptoms associated with autonomic dysfunction in human immunodeficiency virus (HIV)-infected patients on stable combined antiretroviral therapy. Patients infected with HIV reported higher frequencies of dysautonomia symptoms compared with HIV-negative patients, particularly in the autonomic domains related to urinary, sleep, gastroparesis, secretomotor, pupillomotor, and male sexual dysfunction.

AbstractBackgroundHistaminergic neurons of the tuberomammillary nucleus are critical for maintenance of wakefulness and participate in basal ganglia modulation and sympathoexcitation. All of these functions are affected in multiple system atrophy and dementia with Lewy bodies.ObjectivesTo determine the involvement of histaminergic neurons in these synucleinopathies.MethodsImmunocytochemical staining for histidine decarboxylase and stereological cell counts in the posterolateral hypothalamus from six cases with multiple system atrophy, six with dementia with Lewy bodies, and five healthy controls.ResultsCompared with healthy controls, significant reduction of histaminergic neurons was found both in multiple system atrophy (total estimated cell count, 94,677 ± 5,521 vs. 169,579 ± 12,443; P < 0.001) and in dementia with Lewy bodies (91,110 ± 13,021 vs. 169,579 ± 12,443; P < 0.001).ConclusionsLoss of tuberomammillary histaminergic neurons could potentially contribute to motor, sleep, and autonomic manifestations of both multiple system atrophy and dementia with Lewy bodies. © 2015 International Parkinson and Movement Disorder Society

Abstract— We evaluated whether droxidopa, a prodrug converted to norepinephrine, is beneficial in the treatment of symptomatic neurogenic orthostatic hypotension, which results from failure to generate an appropriate norepinephrine response to postural challenge. Patients with symptomatic neurogenic orthostatic hypotension and Parkinson disease, multiple system atrophy, pure autonomic failure, or nondiabetic autonomic neuropathy underwent open-label droxidopa titration (100–600 mg, 3× daily). Responders then received an additional 7-day open-label treatment at their individualized dose. Patients were subsequently randomized to continue with droxidopa or withdraw to placebo for 14 days. We then assessed patient-reported scores on the Orthostatic Hypotension Questionnaire and blood pressure measurements. Mean worsening of Orthostatic Hypotension Questionnaire dizziness/lightheadedness score from randomization to end of study (the primary outcome; N=101) was 1.9±3.2 with placebo and 1.3±2.8 units with droxidopa ( P =0.509). Four of the other 5 Orthostatic Hypotension Questionnaire symptom scores and all 4 symptom-impact scores favored droxidopa, with statistical significance for the patient’s self-reported ability to perform activities requiring standing a short time ( P =0.033) and standing a long time ( P =0.028). Furthermore, a post hoc analysis of a predefined composite score of all symptoms (Orthostatic Hypotension Questionnaire composite) demonstrated a significant benefit for droxidopa ( P =0.013). There was no significant difference between groups for standing systolic blood pressure ( P =0.680). Droxidopa was well tolerated. In summary, this randomized withdrawal droxidopa study failed to meet its primary efficacy end point. Additional clinical trials are needed to confirm that droxidopa is beneficial in symptomatic neurogenic orthostatic hypotension, as suggested by the positive secondary outcomes of this trial. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00633880.

ABSTRACTIntroduction: The aim of this study is to characterize autonomic impairment in motor neuron disease. Methods: Neurological evaluations and autonomic testing were analyzed retrospectively in 132 patients: 86 classic amyotrophic lateral sclerosis (ALS), 36 lower motor neuron (LMN), and 10 upper motor neuron (UMN) predominant disease. Results: One‐third of patients were symptomatic; urinary urgency and constipation were the most frequent symptoms. Increased Composite Autonomic Severity Score (CASS) was present in 75% with mild impairment (CASS 1–3) in 85% and moderate (CASS 4–7) in 15%. The frequencies of testing abnormalities were: sudomotor 46%, cardiovagal 50%, and adrenergic 14%. The UMN group had significantly higher median CASS scores than the classic ALS (P = 0.021) and LMN group (P = 0.018). Conclusions: We found predominantly mild autonomic impairment in ALS patients, with mostly cardiovagal and sudomotor involvement. Moderate autonomic failure occurred in 1 of 7 patients, especially those with an UMN presentation. Patients with selective corticospinal tract involvement may have more impairment of autonomic pathways. Muscle Nerve 51:676–679, 2015