The controversy concerning plasma homocysteine in Parkinson disease patients treated with levodopa alone or with entacapone: effects of vitamin status

Levodopa treatment of Parkinson disease results in hyperhomocysteinemia (HHcy) as a consequence of levodopa methylation by catechol-O-methyltransferase (COMT). Although inhibition of COMT should theoretically prevent or reduce levodopa-induced HHcy, results from several prospective studies are conflicting. Our review of these studies suggests that the ability of COMT inhibition to reduce or prevent levodopa-induced HHcy in Parkinson disease patients may be attributed to differences in the vitamin status of the study participants. In patients with low or low-normal folate levels, levodopa administration is associated with a greater increase in homocysteine and concomitant entacapone administration is associated with a greater reduction in homocysteine.     

Elevated plasma homocysteine levels in patients treated with levodopa: association with vascular disease

BACKGROUND: Hyperhomocysteinemia is a risk factor for vascular disease and potentially for dementia and depression. The most common cause of elevated homocysteine levels is deficiency of folate or vitamin B(12). However, patients with Parkinson disease (PD) may have elevated homocysteine levels resulting from methylation of levodopa and dopamine by catechol O-methyltransferase, an enzyme that uses S-adenosylmethionine as a methyl donor and yields S-adenosylhomocysteine. Since S-adenosylhomocysteine is rapidly converted to homocysteine, levodopa therapy may put patients at increased risk for vascular disease by raising homocysteine levels. OBJECTIVES: To determine whether elevations in plasma homocysteine levels caused by levodopa use are associated with increased prevalence of coronary artery disease (CAD), and to determine what role folate and vitamin B(12) have in levodopa-induced hyperhomocysteinemia. DESIGN/METHODS: Subjects included 235 patients with PD followed up in a movement disorders clinic. Of these, 201 had been treated with levodopa, and 34 had not. Blood samples were collected for the measurement of homocysteine, folate, cobalamin, and methylmalonic acid levels. A history of CAD (prior myocardial infarctions, coronary artery bypass grafting, or coronary angioplasty procedures) was prospectively elicited. We analyzed parametric data by means of 1-way analysis of variance or the t test, and categorical data by means of the Fisher exact test or chi(2) test. RESULTS: Mean +/- SD plasma homocysteine levels were significantly higher in patients treated with levodopa (16.1 +/- 6.2 micro mol/L), compared with levodopa-na?ve patients (12.2 +/- 4.2 micro mol/L; P<.001). We found no difference in the plasma concentration of folate, cobalamin, or methylmalonic acid between the 2 groups. Patients whose homocysteine levels were in the higher quartile (>or=17.7 micro mol/L) had increased prevalence of CAD (relative risk, 1.75; 95% confidence interval, 1.08-2.70;P=.04). CONCLUSIONS: Levodopa therapy, rather than PD, is a cause of hyperhomocysteinemia in patients with PD. Deficiency of folate or vitamin B(12) levels does not explain the elevated homocysteine levels in these patients. To our knowledge, this is the first report that levodopa-related hyperhomocysteinemia is associated with increased risk for CAD. These findings have implications for the treatment of PD in patients at risk for vascular disease, and potentially for those at risk for dementia and depression.     

Conversion from sustained release carbidopa/levodopa to carbidopa/levodopa/entacapone (stalevo) in Parkinson disease patients

OBJECTIVES: This study was performed to determine if conversion from sustained release carbidopa/levodopa (SR-CL) with or without entacapone to carbidopa/levodopa/entacapone (CLE; Stalevo) improves motor functioning and quality of life in Parkinson disease (PD) patients and to assess patient tolerance and drug preference. METHODS: PD patients reporting suboptimal symptom control with SR-CL were converted to CLE. The basic conversion was 1 SR-CL 25/100 to 1 25/100/200 CLE and 1 SR-CL 50/200 to 1 37.5/150/200 CLE with additional changes as necessary. RESULTS: There were 62 patients with an average age of 68 years and an average disease duration of 11 years. CLE was preferred by 42 patients and SR-CL was preferred by 20 patients. In those that preferred CLE, Unified Parkinson Disease Rating Scale (UPDRS) mentation and motor subscores, Parkinson Disease Questionnaire-39 (PDQ-39) quality-of-life activities of daily living (ADL) and bodily discomfort subscores, and Epworth Sleepiness Scale (ESS) scores were significantly improved. There were no significant changes in any measures in the group that preferred SR-CL. Common adverse effects in the group that preferred CLE included nausea, vomiting, increased dyskinesia or off time, dizziness, and somnolence. The most common adverse events in the group preferring SR-CL were increased off time or dyskinesia, nausea, and vomiting. CONCLUSIONS: A majority of patients suboptimally controlled on SR-CL can be successfully converted to CLE with improvements in motor function, quality of life, and sleepiness. Older patients, with longer disease duration not previously exposed to entacapone, may better tolerate CLE after the addition of entacapone.     

Plasma homocysteine levels in patients treated with levodopa: motor and cognitive associations

OBJECTIVE: The aim of this study was to determine whether hyperhomocysteinemia caused by levodopa used in idiopathic Parkinson's disease (IPD) is associated with cognitive or physical impairments. The role of folate and vitamin B12 levels in this context was also ascertained. METHODS: Thirty-nine patients who had been followed with the diagnosis of IPD in our clinic for > 2 years and 28 healthy control subjects with similar demographic features were included in the study. The homocysteine, folic acid and vitamin B12 levels and the results of the short test of mental status (STMS) and the clock drawing test of IPD patients were compared with those of the controls. Subsequently, the patients with a homocysteine level of >14 micromol/l were compared with those having a homocysteine level of <14 micromol/l by means of detailed neuropsychometric test batteries. RESULTS: Homocysteine levels were significantly higher in the patient group in comparison with the controls. There was a negative correlation between hyperhomocysteinemia and the levels of vitamin B12 and folate. On the other hand, a positive correlation between hyperhomocysteinemia and the levodopa dose was detected. There was a positive correlation between hyperhomocysteinemia and unified Parkinson's disease rating scale (UPDRS) motor section. The critical dose of levodopa was observed to be 300 mg/d. In terms of cognitive and frontal functions, no significant difference was detected between the patients and control group. The subgroup with a homocysteine level of >14 micromol/l had a significantly poorer performance in frontal and memory tests. DISCUSSION: In patients with IPD who are detected to have hyperhomocysteinemia, the assessment of the cognitive performance, folic acid and vitamin B12 levels and the supplementation of folic acid and vitamin B12 to the treatment regimen might be appropriate.     

Elevation of total homocysteine levels in patients with Parkinson's disease treated with duodenal levodopa/carbidopa gel

Levodopa/carbidopa (LD/CD) application elevates total plasma homocysteine (thcys). We determined thcys-, LD- and 3-O-methyldopa (3-OMD) concentrations in 28 patients with Parkinson??s disease (PD) on a LD/CD duodenal gel treatment. We found a distinct thcys increase (29.52?±?28.98???mol/l [median?±?SD]) above the 15???mol/l threshold and a significant (R?=?0.7) correlation between LD and 3-OMD. thcys ascent was observed in relation with the onset of atherosclerosis, non-motor symptoms and polyneuropathy in PD patients in the long term.     

Quality of life in early Parkinson's disease treated with levodopa/carbidopa/entacapone

We aimed to investigate whether treatment with levodopa/carbidopa/entacapone when compared with levodopa/carbidopa improves quality of life in Parkinson's disease (PD) patients with no or minimal, nondisabling motor fluctuations. This is a multicenter, randomized, double‐blind study. One hundred eighty‐four patients on 3 to 4 equal doses of 100/25 to 200/50 mg levodopa/carbidopa or levodopa/benserazide, 0 to 3 hours of nondisabling OFF time over a 48 hour period and no dyskinesia were randomized to levodopa/carbidopa/entacapone or levodopa/carbidopa treatment for 12 weeks. The primary outcome measure was quality of life as assessed by the PDQ‐8. Secondary outcome measures were the UPDRS parts I–IV, and the Wearing Off Card. Treatment with levodopa/carbidopa/entacapone resulted in significantly greater improvements in PDQ‐8 scores compared to treatment with levodopa/carbidopa (mean difference 1.4 points, P = 0.021). Statistically significant improvements were seen predominantly in nonmotor domains (depression, personal relationships, communication, stigma, all P < 0.05; dressing P = 0.056). Patients who were randomly assigned to levodopa/carbidopa/entacapone also showed significantly greater improvement in UPDRS part II scores (P = 0.032) with UPDRS part III scores showing borderline significance. Differences in UPDRS parts I and IV and Wearing Off Card scores were not significant. Treatment with levodopa/carbidopa/entacapone results in improved quality of life compared with levodopa/carbidopa in PD patients with mild or minimal, nondisabling motor fluctuations. © 2007 Movement Disorder Society     

Plasma homocysteine levels in pergolide-treated Parkinson disease patients

Hyperhomocysteinemia is as a risk factor for increased vascular disease in l-dopa-treated Parkinson disease (PD) patients. This effect of l-dopa is associated with the metabolism of l-dopa by methylation. This study aimed to assess the effect of pergolide on plasma homocysteine levels. Plasma homocysteine levels were compared between PD patients treated with pergolide as monotherapy, with l-dopa as monotherapy, or with an l-dopa and pergolide combination and compared with controls. Plasma homocysteine levels were significantly higher in the l-dopa monotherapy group, and there were no significant differences for the pergolide treatment groups. Pergolide can be beneficial for increased plasma homocysteine levels.     

Levodopa intake increases plasma levels of S-adenosylmethionine in treated patients with Parkinson disease

Metabolism of levodopa via the enzyme catechol-O-methyltransferase requires S-adenosylmethionine (SAM) as a methyl donor. SAM caused Parkinson disease (PD)-like symptoms in rodents. Therefore, SAM could contribute to a decreased efficacy of levodopa in the long term. SAM levels were significantly reduced in levodopa-treated PD patients, but they showed increased enzyme methionine adenosyl transferase (MAT) activity, which induces SAM synthesis from methionine (MET). This may result from a rebound increase of SAM production. The objective of the study was to demonstrate an effect of acute levodopa intake on SAM synthesis in the plasma of treated PD patients. The authors measured SAM, MET, and levodopa plasma concentrations in 13 levodopa-treated PD patients before and after application of 125 mg levodopa/benserazide. Plasma levels of SAM and levodopa significantly increased, but MET concentrations did not significantly decrease. The SAM increase after levodopa intake may exert both a certain antidepressant and cognitive function improving effect. This is often observed in untreated PD patients who receive levodopa for the first time, or in more advanced, fluctuating PD patients, when they turn from the OFF to the ON phase. Because SAM in higher dosages may also counteract the antiparkinsonian efficacy of levodopa according to animal trials, this SAM increase may hypothetically contribute to the onset of wearing-off phenomena and other clinical signs of limited efficacy of levodopa during long-term treatment with levodopa in PD patients.     

丙戊酸单药治疗与癫痫患者血浆同型半胱氨酸水平间关系的Meta分析

目的分析癫痫患者血浆同型半胱氨酸水平变化与丙戊酸单药治疗间的关系。方法选择epileDsv、valproate、homocysteine和epilep。为检索词,计算机检索1990年1月-2013年8月美国国立医学图书馆、科学引文索引数据库、荷兰医学文摘等数据库,获得丙戊酸单药治疗与癫痫患者血浆同型半胱氨酸水平间关系的相关英文文献,均为丙戊酸单药治疗的癫痫患者与正常对照受试者血浆同型半胱氨酸水平比较的病例．对照临床研究。通过Newcastle—Ottawa量表独立进行文献质量评价和数据提取,Stata12．0统计软件行Meta分析。结果共纳入符合条件的英文文献8篇,包括266例行丙戊酸单药治疗的癫痼患者和489例正常对照受试者,所有纳入文献质量评分均〉6分。Meta分析显示,丙戊酸单药治疗组患者血浆同型半胱氨酸水平显著高于正常对照组[标准化均数差（SMD）：0．620,95％CI：0．320-0．920;P=0．000];经异质性检验存在显著异质性（I^2=65．600％,P=0．005）,根据不同地区和受试者年龄差异行进一步亚组分析,结果显示西亚组癫痫患者异质性风险（I^2=47．400％,P=0．107）较整体（I^2=65．600％,P=0．005）降低。采用敏感性分析评价Meta分析之稳定性,当任何一项研究被剔除后,相应的SMD值均不发生变化,表明分析结果稳定性良好。结论丙戊酸单药治疗可显著增加癫痫患者血浆同型半胱氨酸水平,后者是否受种族因素的影响尚待进一步研究。     

Impact of levodopa on reduced nerve growth factor levels in patients with Parkinson disease

The author s found 6.5-fold reduced nerve growth factor (NGF) levels in the plasma of treated patients with Parkinson disease (PD) compared with healthy control subjects (P = 0.03). A significant positive correlation between levodopa and NGF plasma levels appeared after acute levodopa/benserazide administration. The data suggest that acute levodopa administration may contribute to an increase of NGF plasma concentrations, which are reduced in treated PD patients due to the ongoing disease process itself or chronic antiparkinsonian drug treatment.     

Double‐blind trial of levodopa/carbidopa/entacapone versus levodopa/carbidopa in early Parkinson's disease

We performed a 39‐week, randomized, double‐blind, multicenter study to compare the efficacy, safety, and tolerability of levodopa/carbidopa/entacapone (LCE, Stalevo) with levodopa/carbidopa (LC, Sinemet IR) in patients with early Parkinson's disease (PD). Four hundred twenty‐three patients with early PD warranting levodopa were randomly assigned to treatment with LCE 100/25/200 or LC 100/25 three‐times daily. The adjusted mean difference in total Unified Parkinson's disease Rating Scale (UPDRS) Parts II and III between groups using the analysis of covariance model (prespecified primary outcome measure) was 1.7 (standard error = 0.84) points favoring LCE (P = 0.045). Significantly greater improvement with LCE compared with LC was also observed in UPDRS Part II activities of daily living (ADL) scores (P = 0.025), Schwab and England ADL scores (blinded rater, P = 0.003; subject, P = 0.006) and subject‐reported Clinical Global Impression (CGI) scores (P = 0.047). There was no significant difference in UPDRS Part III or investigator‐rated CGI scores. Wearing‐off was observed in 29 (13.9%) subjects in the LCE group and 43 (20.0%) in the LC group (P = 0.099). Dyskinesia was observed in 11 (5.3%) subjects in the LCE group and 16 (7.4%) in the LC group (P = 0.367). Nausea and diarrhea were reported more frequently in the LCE group. LCE provided greater symptomatic benefit than LC and did not increase motor complications. © 2008 Movement Disorder Society     

美多芭联合恩他卡朋治疗对帕金森病患者血浆同型半胱氨酸水平的影响

目的探讨美多芭联合恩他卡朋治疗对帕金森病(PD)患者血浆同型半胱氨酸(Hcy)水平的影响。方法选取30名健康体检者作为对照组,20例未服用过左旋多巴(LD)制剂的PD患者为未服药组,63例美多芭治疗的PD患者为美多芭组,49例美多芭联合恩他卡朋治疗的PD患者为联合组。检测患者外周血中的LD稳态峰浓度并进行统一PD评分量表Ⅲ(UPDRSⅢ)的评分。检测所有研究对象的血浆Hcy水平。结果联合组患者LD血浆浓度明显高于美多芭组(P0.05)。美多芭组及联合组患者UPDRSⅢ评分均明显低于未服药组(均P0.05)。与对照组比较,未服药组、美多芭组及联合组患者血浆Hcy水平均明显升高(均P0.05);且美多芭组患者血浆Hcy水平明显高于未服药组及联合组(均P0.05)。结论美多芭联合恩他卡朋能显著降低PD患者血浆Hcy水平,对PD治疗有积极意义。