Inosine to increase serum and cerebrospinal fluid urate in Parkinson disease: a randomized clinical trial.

IMPORTANCE: Convergent biological, epidemiological, and clinical data identified urate elevation as a candidate strategy for slowing disability progression in Parkinson disease (PD). OBJECTIVE: To determine the safety, tolerability, and urate-elevating capability of the urate precursor inosine in early PD and to assess its suitability and potential design features for a disease-modification trial. DESIGN, SETTING, AND PARTICIPANTS: The Safety of Urate Elevation in PD (SURE-PD) study, a randomized, double-blind, placebo-controlled, dose-ranging trial of inosine, enrolled participants from 2009 to 2011 and followed them for up to 25 months at outpatient visits to 17 credentialed clinical study sites of the Parkinson Study Group across the United States. Seventy-five consenting adults (mean age, 62 years; 55% women) with early PD not yet requiring symptomatic treatment and a serum urate concentration less than 6 mg/dL (the approximate population median) were enrolled. INTERVENTIONS: Participants were randomized to 1 of 3 treatment arms: placebo or inosine titrated to produce mild (6.1-7.0 mg/dL) or moderate (7.1-8.0 mg/dL) serum urate elevation using 500-mg capsules taken orally up to 2 capsules 3 times per day. They were followed for up to 24 months (median, 18 months) while receiving the study drug plus 1 washout month. MAIN OUTCOMES AND MEASURES: The prespecified primary outcomes were absence of unacceptable serious adverse events (safety), continued treatment without adverse event requiring dose reduction (tolerability), and elevation of urate assessed serially in serum and once (at 3 months) in cerebrospinal fluid. RESULTS Serious adverse events (17), including infrequent cardiovascular events, occurred at the same or lower rates in the inosine groups relative to placebo. No participant developed gout and 3 receiving inosine developed symptomatic urolithiasis. Treatment was tolerated by 95% of participants at 6 months, and no participant withdrew because of an adverse event. Serum urate rose by 2.3 and 3.0 mg/dL in the 2 inosine groups (P < .001 for each) vs placebo, and cerebrospinal fluid urate level was greater in both inosine groups (P = .006 and <.001, respectively). Secondary analyses demonstrated nonfutility of inosine treatment for slowing disability. CONCLUSIONS AND RELEVANCE: Inosine was generally safe, tolerable, and effective in raising serum and cerebrospinal fluid urate levels in early PD. The findings support advancing to more definitive development of inosine as a potential disease-modifying therapy for PD. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00833690.

Caffeine consumption and risk of dyskinesia in CALM-PD.

BACKGROUND: Adenosine A2A receptor antagonists reduce or prevent the development of dyskinesia in animal models of levodopa-induced dyskinesia. METHODS: We examined the association between self-reported intake of the A2A receptor antagonist caffeine and time to dyskinesia in the Comparison of the Agonist Pramipexole with Levodopa on Motor Complications of Parkinson's Disease (CALM-PD) and CALM Cohort extension studies, using a Cox proportional hazards model adjusting for age, baseline Parkinson's severity, site, and initial treatment with pramipexole or levodopa. RESULTS: For subjects who consumed >12 ounces of coffee/day, the adjusted hazard ratio for the development of dyskinesia was 0.61 (95% CI, 0.37-1.01) compared with subjects who consumed <4 ounces/day. For subjects who consumed between 4 and 12 ounces/day, the adjusted hazard ratio was 0.73 (95% CI, 0.46-1.15; test for trend, P = .05). CONCLUSIONS: These results support the possibility that caffeine may reduce the likelihood of developing dyskinesia.

Effects of simvastatin on cholesterol metabolism and Alzheimer disease biomarkers.

Preclinical and epidemiologic studies suggest a protective effect of statins on Alzheimer disease (AD). Experimental evidence indicates that some statins can cross the blood-brain barrier, alter brain cholesterol metabolism, and may ultimately decrease the production of amyloid-beta (Abeta) peptide. Despite these promising leads, clinical trials have yielded inconsistent results regarding the benefits of statin treatment in AD. Seeking to detect a biological signal of statins effect on AD, we conducted a 12-week open-label trial with simvastatin 40 mg/d and then 80 mg/d in 12 patients with AD or amnestic mild cognitive impairment and hypercholesterolemia. We quantified cholesterol precursors and metabolites and AD biomarkers of Abeta and tau in both plasma and cerebrospinal fluid at baseline and after the 12-week treatment period. We found a modest but significant inhibition of brain cholesterol biosynthesis after simvastatin treatment, as indexed by a decrease of cerebrospinal fluid lathosterol and plasma 24S-hydroxycholesterol. Despite this effect, there were no changes in AD biomarkers. Our findings indicate that simvastatin treatment can affect brain cholesterol metabolism within 12 weeks, but did not alter molecular indices of AD pathology during this short-term treatment.

Urate as a predictor of the rate of clinical decline in Parkinson disease.

BACKGROUND: The risk of Parkinson disease (PD) and its rate of progression may decline with increasing concentration of blood urate, a major antioxidant. OBJECTIVE: To determine whether serum and cerebrospinal fluid concentrations of urate predict clinical progression in patients with PD. DESIGN, SETTING, AND PARTICIPANTS: Eight hundred subjects with early PD enrolled in the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) trial. The pretreatment urate concentration was measured in serum for 774 subjects and in cerebrospinal fluid for 713 subjects. MAIN OUTCOME MEASURES: Treatment-, age-, and sex-adjusted hazard ratios (HRs) for clinical disability requiring levodopa therapy, the prespecified primary end point of the original DATATOP trial. RESULTS: The HR of progressing to the primary end point decreased with increasing serum urate concentrations (HR for highest vs lowest quintile = 0.64; 95% confidence interval [CI], 0.44-0.94; HR for a 1-SD increase = 0.82; 95% CI, 0.73-0.93). In analyses stratified by alpha-tocopherol treatment (2000 IU/d), a decrease in the HR for the primary end point was seen only among subjects not treated with alpha-tocopherol (HR for a 1-SD increase = 0.75; 95% CI, 0.62-0.89; vs HR for those treated = 0.90; 95% CI, 0.75-1.08). Results were similar for the rate of change in the Unified Parkinson's Disease Rating Scale score. Cerebrospinal fluid urate concentration was also inversely related to both the primary end point (HR for highest vs lowest quintile = 0.65; 95% CI, 0.44-0.96; HR for a 1-SD increase = 0.89; 95% CI, 0.79-1.02) and the rate of change in the Unified Parkinson's Disease Rating Scale score. As with serum urate concentration, these associations were present only among subjects not treated with alpha-tocopherol. CONCLUSIONS: Higher serum and cerebrospinal fluid urate concentrations at baseline were associated with slower rates of clinical decline. The findings strengthen the link between urate concentration and PD and the rationale for considering central nervous system urate concentration elevation as a potential strategy to slow PD progression.

Age but not diagnosis is the main predictor of plasma amyloid beta-protein levels.

BACKGROUND: Plasma amyloid beta-protein Abeta42 levels are increased in patients with familial Alzheimer disease (AD) mutations, and high levels reportedly identify individuals at risk to develop AD. OBJECTIVES: To determine whether there are characteristic changes in plasma Abeta40 and Abeta42 levels in sporadic AD, and to examine the relationship of plasma Abeta measures with clinical, demographic, and genetic variables in a prospectively characterized outpatient clinic population. PATIENTS: A total of 371 outpatients with sporadic AD (n = 146), mild cognitive impairment (n = 37), or Parkinson disease (n = 96) and nondemented control cases (n = 92). METHODS: We collected plasma samples and determined Abeta40 and Abeta42 levels by sandwich enzyme-linked immunosorbent assay with the use of the capture antibody BNT77 (anti-Abeta11-28) and the detector antibodies horseradish peroxidase-linked BA27 (anti-Abeta40) and BC05 (anti-Abeta42). RESULTS: Mean Abeta40 and Abeta42 levels increased significantly with age in each diagnostic group. When covaried for age, mean plasma levels of Abeta40 and Abeta42 did not differ significantly among the 4 diagnostic groups. Within the mild cognitive impairment and AD groups, Abeta40 and Abeta42 levels did not correlate with duration of memory impairment or with cognitive test scores. The Abeta measures were not influenced by family history of AD, apolipoprotein E genotype, or current medication use of cholinesterase inhibitors, vitamin E, statins, nonsteroidal anti-inflammatory drugs, or estrogen. CONCLUSIONS: Plasma Abeta measures increase with age, but, in contrast to reports on familial AD, plasma Abeta measures were neither sensitive nor specific for the clinical diagnosis of mild cognitive impairment or sporadic AD.