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Schwarzschild MA, Ascherio A, Beal MF, Cudkowicz ME, Curhan GC, Hare JM, Hooper DC, Kieburtz KD, Macklin EA, Oakes D, Rudolph A, Shoulson I, Tennis MK, Espay AJ, Gartner M, Hung A, Bwala G, Lenehan R, Encarnacion E, Ainslie M, Castillo R, Togasaki D, Barles G, Friedman JH, Niles L, Carter JH, Murray M, Goetz CG, Jaglin J, Ahmed A, Russell DS, Cotto C, Goudreau JL, Russell D, Parashos SA, Ede P, Saint-Hilaire MH, Thomas CA, James R, Stacy MA, Johnson J, Gauger L, Antonelle de Marcaida J, Thurlow S, Isaacson SH, Carvajal L, Rao J, Cook M, Hope-Porche C, McClurg L, Grasso DL, Logan R, Orme C, Ross T, Brocht AFD, Constantinescu R, Sharma S, Venuto C, Weber J, Eaton K. Inosine to increase serum and cerebrospinal fluid urate in Parkinson disease: a randomized clinical trial. JAMA Neurol 2014; 71:141-50. [PMID: 24366103 DOI: 10.1001/jamaneurol.2013.5528] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
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.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - David Oakes
- University of Rochester, Rochester, New York
| | | | | | | | | | | | - Albert Hung
- Massachusetts General Hospital, Boston, Massachusetts
| | - Grace Bwala
- Massachusetts General Hospital, Boston, Massachusetts
| | - Richard Lenehan
- Scott & White Memorial Hospital/Texas A&M University, Temple
| | | | - Melissa Ainslie
- Scott & White Memorial Hospital/Texas A&M University, Temple
| | | | | | - Gina Barles
- University of Southern California, Los Angeles
| | | | - Lisa Niles
- Butler Hospital, Providence, Rhode Island
| | | | | | | | - Jeana Jaglin
- Rush University Medical Center, Chicago, Illinois
| | | | - David S Russell
- Institute of Neurodegenerative Disorders, New Haven, Connecticut
| | - Candace Cotto
- Institute of Neurodegenerative Disorders, New Haven, Connecticut
| | | | | | | | - Patricia Ede
- Struthers Parkinson's Center, Golden Valley, Minnesota
| | | | | | | | | | | | | | | | | | - Stuart H Isaacson
- Parkinson's Disease & Movement Disorder Center of Boca Raton, Boca Raton, Florida
| | - Lisbeth Carvajal
- Parkinson's Disease & Movement Disorder Center of Boca Raton, Boca Raton, Florida
| | | | - Maureen Cook
- Ochsner Clinic Foundation, New Orleans, Louisiana
| | | | - Lauren McClurg
- Administrative Coordination Center, Massachusetts General Hospital, Boston
| | - Daniela L Grasso
- Administrative Coordination Center, Massachusetts General Hospital, Boston
| | - Robert Logan
- Administrative Coordination Center, Massachusetts General Hospital, Boston
| | - Constance Orme
- Clinical Coordination Center, University of Rochester, Rochester, New York
| | - Tori Ross
- Clinical Coordination Center, University of Rochester, Rochester, New York
| | - Alicia F D Brocht
- Clinical Coordination Center, University of Rochester, Rochester, New York
| | | | - Saloni Sharma
- Clinical Coordination Center, University of Rochester, Rochester, New York
| | - Charles Venuto
- Clinical Coordination Center, University of Rochester, Rochester, New York
| | - Joseph Weber
- Clinical Coordination Center, University of Rochester, Rochester, New York
| | - Ken Eaton
- Clinical Coordination Center, University of Rochester, Rochester, New York
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Abstract
This study investigated the relation of muscle fiber conduction velocity (MFCV) to difference power spectrum mean frequency (MF), their fatigue trends, and differences between their values and their fatigue trends in various neuromuscular disorders. Electromyographic interference pattern was recorded inside the biceps in continuous isometric maximal voluntary contractions. Each subject was encouraged to pull for as long as possible. Fatigue was calculated as percent of time to complete inability to sustain contraction. The MFCV was computed by cross-correlation. The MF was computed by differencing, windowing, FFT, squaring of coefficient, and repeat averaging. There were 33 healthy, 86 polyneuropathic, 28 myasthenic, 13 myotonic, and 32 myopathic patients. Both MFCV and MF changed significantly with fatigue--the MFCV linearly, while the MF in a markedly nonlinear fashion. Both were found to be insensitive to the end stages of muscle fatigue--the MFCV did not change its slope toward complete fatigue, and the MF did not change at all beyond the 40% fatigue point. A statistically sound fatigue regression equation was derived for each, and a nonlinear equation was found to best describe their relationship. Neither MFCV nor its fatigue changes were found to be significantly different across the neuromuscular disorders. The MF, however, was found to be significantly different in some neuromuscular disorders in both its average values and fatigue trends. This study showed, in contrast to the literature, a nonlinear relationship between MFCV and MF. It also shows that neither the MFCV nor the MF had reasonable diagnostic power on its own; however, the MF was very promising to serve as an adjunct to other variables.
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Affiliation(s)
- I Yaar
- Neurology Section, VA Medical Center, Providence, Rhode Island 02908
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