Efficacy and Safety of Pramipexole Sustained Release versus Immediate Release Formulation for Nocturnal Symptoms in Chinese Patients with Advanced Parkinson's Disease: A Pilot Study.

OBJECTIVE: To explore the efficacy and safety of pramipexole sustained release (SR) versus pramipexole immediate release (IR) in treating nocturnal symptoms in levodopa-treated Chinese patients with advanced Parkinson's disease (PD) and sleep disturbances. METHOD: SUSTAIN was an open-label, randomised, active-controlled parallel group exploratory pilot study (NCT03521635). A total of 98 patients were randomly allocated (1 : 1) to either pramipexole SR (n = 49) or pramipexole IR (n = 49) groups. The primary endpoint was a change from baseline in PD Sleep Scale 2nd version (PDSS-2) total score at 18 weeks. A reduction in score represents improvement. Secondary endpoints included Nocturnal Hypokinesia Questionnaire, Scales for Outcomes in PD Sleep Scale, Early Morning Off (EMO), Epworth Sleepiness Scale, PD Questionnaire-8, and responder rates as measured by PDSS-2 total score (<18), EMO scores (≥1 point change), Clinical Global Impression Improvement scale, and Patient Global Impression-Improvement scale. Other endpoints included motor complications (MDS-UPDRS part IV) score. Adverse events were evaluated for each group. RESULTS: The mean pramipexole dose for both groups was 1.5 mg/day at week 18, and the mean changes in PDSS-2 total score for pramipexole SR and IR were -13.7 (95% CI -16.0 to -11.4) and -14.4 (-16.8 to -12.0) (difference of 0.7; p=0.688). Change from baseline for both groups achieved the minimal clinical important difference threshold (MCID = -3.44). No significant difference was observed in change from baseline for other measures of sleep-related disturbances or responder rates. For motor complications, a greater improvement in MDS-UPDRS part IV score was observed in pramipexole SR over IR (-3.4 vs -2.3; treatment group difference: -1.1; p=0.036). Both groups had comparable safety profiles. CONCLUSION: In Chinese patients with advanced PD and sleep disturbances, pramipexole SR and IR have similar benefits in the treatment of nocturnal symptoms and safety, and an improvement from baseline in nocturnal symptoms was observed regardless of pramipexole formulation.

Efficacy and safety of rasagiline in Chinese patients with early Parkinson's disease: a randomized, double-blind, parallel, placebo-controlled, fixed-dose study.

BACKGROUND: Rasagiline is a monoamine oxidase-B inhibitor used for Parkinson's disease (PD) treatment, but its effectiveness on Chinese patients is unclear. This study aimed to evaluate the efficacy and safety of rasagiline monotherapy in Chinese patients with early PD. METHODS: A 26-weeks, randomized, double-blind, placebo-controlled study has been performed at 15 sites in China and enrolled outpatients (≥35 years old) with idiopathic PD without a history of using any dopaminergic drugs. Participants were randomized 1:1 to receive rasagiline 1 mg once daily or placebo. The primary endpoint was the change of the Unified Parkinson's Disease Rating Scale (UPDRS) total score from baseline to 26 weeks treatment. Secondary endpoints included changes in UPDRS subscale scores from part I to III. Health status was assessed with the PD Questionnaire (PDQ)-39 and EuroQol-Five-Dimension (EQ-5D) questionnaire. Safety profile was collected until 30 weeks after randomization. RESULTS: A total of 130 patients (n = 65/group) were recruited, and 127 (rasagiline, n = 64; placebo, n = 63) were included in the full analysis set. Baseline characteristics were comparable between the two groups. The decrease in the mean UPDRS total score was greater in the rasagiline group than in the placebo group (- 3.18 ± 0.95 vs. - 0.18 ± 0.98, P = 0.025), and the mean UPDRS part I non-motor symptoms score (- 0.54 ± 0.15 vs. -0.08 ± 0.15, P = 0.003) were significantly decreased in the rasagiline group compared with placebo treated patients. An improvement trend was observed in the active treatment group for the subscales evaluation with parts II and III, while the difference to placebo was not statistically significant. Life quality assessed by the EQ-5D visual analog scale improved in the rasagiline group but worsened in placebo treated patients. The overall incidence of treatment-emergent adverse events (AEs) was slightly lower in the rasagiline group (41.5%) than in the placebo group (46.2%). CONCLUSIONS: Rasagiline is effective, safe, and well tolerated as monotherapy for the treatment of Chinese PD patients. TRIAL REGISTRATION: Clinicaltrials.gov: NCT01556165. Registered 13 Mar 2012.

Adjunct rasagiline to treat Parkinson's disease with motor fluctuations: a randomized, double-blind study in China.

BACKGROUND: The use of adjunct rasagiline in levodopa-treated patients with Parkinson's disease and motor fluctuations is supported by findings from large-scale clinical studies. This study is to investigate the efficacy and safety of adjunct rasagiline in Chinese patients with Parkinson's disease, as a product registration study. METHODS: This 16-week, randomized, double-blind, parallel-group, multicenter, placebo-controlled study of rasagiline 1 mg/day included levodopa-treated patients with Parkinson's disease and motor fluctuations. The primary efficacy endpoint was mean change from baseline in total daily OFF time over 16 weeks. Secondary endpoints were Clinical Global Impressions - Improvement (CGI-I), and change in Unified Parkinson's Disease Rating Scale (UPDRS) Activities of daily living (ADL) and Motor scores. Patient well-being (EQ-5D), and the frequency of adverse events were also assessed. RESULTS: In total, 324 levodopa-treated patients were randomized to rasagiline 1 mg/day (n = 165) or placebo (n = 159). Over 16 weeks, rasagiline statistically significantly reduced the mean [95% confidence interval] total daily OFF time versus placebo (- 0.5 h [- 0.92, - 0.07]; p = 0.023). There were also statistically significant improvements versus placebo in CGI-I (- 0.4 points [- 0.61, - 0.22]; p < 0.001), UPDRS-ADL OFF (- 1.0 points [- 1.75, - 0.27]; p = 0.008), and UPDRS-Motor ON (- 1.6 points [- 3.05, - 0.14]; p = 0.032) scores, as well as the EQ-5D utility index (p < 0.05). Rasagiline was safe and well tolerated. CONCLUSIONS: In levodopa-treated Chinese patients with Parkinson's disease and motor fluctuations, adjunct rasagiline 1 mg/day statistically significantly reduced OFF time, and improved daily function and overall well-being, versus placebo. Consistent with findings in other countries, adjunct rasagiline was proven efficacious and well tolerated in Chinese patients. TRIAL REGISTRATION NUMBER: NCT01479530. Registered 22 November 2011.

Analysis of pramipexole dose-response relationships in Parkinson's disease.

BACKGROUND: Pramipexole (PPX), a non-ergot dopamine receptor agonist, is a first-line treatment for Parkinson's disease (PD). A critical dose level above which a better benefit-to-harm ratio exists has not been examined. METHODS: Chinese PD patients (n=464) were retrospectively analyzed by PPX maintenance dose, PD stage, combined levodopa dose, and baseline tremor contribution. The sum score of Baseline Activities of Daily Living (part II) and Motor Examination (III) of the Unified Parkinson's Disease Rating Scale (UPDRS II+III) was used as a covariate for final score adjustment. RESULTS: Sustained-release (SR) and immediate-release (IR) PPX showed similar efficacy based on score changes at 18 weeks, with comparable tolerability. Approximately two-third of patients received PPX at ≥1.5 mg/d, and one fourth of patients had ≥20% tremor contribution to UPDRS II+III. After treatment, patients receiving PPX ≥1.5 mg/d showed better improvement in UPDRS II+III scores (P=0.0025), with similar trends with the IR and SR formulations. Patients with ≥20% tremor contribution showed better improvement in UPDRS II+III scores (P=0.0017). No differences were seen based on PD stage or combined levodopa dose. The overall proportions of adverse events (AEs) were similar. More patients discontinued because of intolerable side effects, and more investigator-defined drug-related AEs were recorded in the <1.5 mg/d subgroup. CONCLUSION: UPDRS II+III improvement was better with PPX ≥1.5 than with <1.5 mg/d in Chinese PD patients after 18 weeks of treatment, with similar trends seen with IR and SR formulations. The frequency of AEs in PPX ≥1.5 and <1.5 mg/d subgroups was similar.

The recommendations of Chinese Parkinson's disease and movement disorder society consensus on therapeutic management of Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is a chronic, progressive and debilitating disease, which affects over 2.5 million people in China. PD is characterized clinically by resting tremor, muscular rigidity, bradykinesia and postural instability. As the disease progresses, additional complications can arise such as non-motor and neurobehavioral symptoms. Pharmacological treatment and surgical intervention for PD have been implemented in China. Until 10 years ago, there was lack of standardization for the management of PD in different regions and among different physicians, leading to different treatment levels in different regions and different physicians. Since then, the Chinese Parkinson's Disease and Movement Disorder Society have published three versions of guidelines for the management of PD in China, in 2006, 2009 and 2014, respectively. Correspondingly, the overall level of treatment for PD in China improved. OBJECTIVES: To update the treatment guidelines based on current foreign and domestic practice guidelines and clinical evidence, and to improve the treatment options available to physicians in the management of PD. SUMMARY: A variety of treatment recommendations in the treatment guidelines have been proposed, including physical activity and disease-modifying medication, which should be initiated at the early-stage of the disease. The principles of dosage titration should be followed to avoid acute adverse reactions to the drugs, to achieve a satisfactory clinical effect with a low dose and to reduce the incidence of long-term motor complications. Moreover, different treatment strategies should be considered at different stages of the disease. Importantly, treatment guidelines and personalized treatments should be valued equally. A set of treatment recommendations has been developed to assist physicians to improve and optimize clinical outcomes for patients with PD in China.

Down regulation of lncSCIR1 after spinal cord contusion injury in rat.

Extensive changes occur at transcriptional level after traumatic spinal cord injury (SCI). In this study, we performed a large scale screening of expression changes of long (>200 nt) RNA transcripts including both coding and non-coding RNA species in a rat contusion SCI model. We validated significant down-regulation of one long non-coding RNA (lncSCIR1) at 1, 4, and 7 days postinjury. lncSCIR1 knockdown promoted astrocyte proliferation and migration in vitro. We further validated the strong association between lncSCIR1 knock down and the expression changes of four mRNAs after injury. Our data indicated that lncSCIR1 down-regulation might play a detrimental role in the pathophysiology of traumatic SCI and thereby provided new insights into the studies of potential therapeutic targets for traumatic central nervous system (CNS) injuries.

Rotigotine in the treatment of primary restless legs syndrome: A meta-analysis of randomized placebo-controlled trials.

The aim of this study was to summarize the efficacy and tolerability of rotigotine in the treatment of primary restless legs syndrome (RLS). PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for English-language randomized controlled trials (RCTs) that assessed the effectiveness of rotigotine for RLS. The pooled mean change from baseline in International RLS (IRLS) Study Group Rating Scalescore and relative risk (RR) of response based on the Clinical Global Impression-Improvement (CGI-I) scale score were applied to evaluate the outcomes. The pooled proportions of adverse events (AEs) were also estimated. Six RCTs were included. The meta-analysis showed a favorable effectiveness of rotigotine versus placebo on RLS [mean change on IRLS score: mean difference (MD)=-4.80; 95% confidence interval (CI): -5.90 to -3.70; P<0.00001 and RR of response on CGI-I was 2.19; 95% CI: 1.86 to 2.58, P<0.00001]. The most common AEs were application site reactions, nausea, headache and fatigue. In general, rotigotine was well-tolerated in patients with primary RLS. Based on the findings from the meta-analysis, rotigotine was more significantly efficacious in the treatment of RLS than placebo. Nevertheless, long-term studies and more evidence of comparisons of rotigotine with other dopamine agonists are needed.

The efficacy and safety of pramipexole ER versus IR in Chinese patients with Parkinson's disease: a randomized, double-blind, double-dummy, parallel-group study.

OBJECTIVE: To evaluate the non-inferiority of pramipexole extended-release (ER) versus immediate-release (IR) in Chinese patients with Parkinson's disease (PD) in a double-blind, randomized, parallel-group study. METHODS: Subjects were Chinese patients with idiopathic PD with diagnosis ≥ 2 years prior to trial, age ≥ 30 years old at diagnosis, and Modified Hoehn and Yahr score 2-4 during 'on'-time. Subjects received treatment with pramipexole ER (n=234) or IR (n=239). Non-inferiority was based on the primary endpoint, the change from baseline to end of maintenance (week 18) in the UPDRS (Parts II + III) total score. RESULTS: For the primary endpoint, the adjusted mean changes (standard error) of UPDRS Parts II + III at week 18 were -13.81 (0.655) and -13.05 (0.643) for ER and IR formulations, respectively, using ANCOVA adjusted for treatment and centre (fixed effect) and baseline (covariate). The adjusted mean between group difference was 0.8 for the 2-sided 95% CI (-1.047, 2.566). Since the lower limit of the 2-sided 95% CI (-1.047) for treatment difference was higher than the non-inferiority margin of -4, non-inferiority between pramipexole ER and IR was demonstrated. The incidence of adverse events (AEs) was 68.8% in the ER arm and 73.6% in the IR arm with few severe AEs (ER: 2.1%; IR: 3.8%). CONCLUSION: Based on the UPDRS II + III score, pramipexole ER was non-inferior to pramipexole IR. The safety profiles of pramipexole ER and IR were similar. These results were based on comparable mean daily doses and durations of treatment for both formulations.

Changes of c-fos, malondialdehyde and lactate in brain tissue after global cerebral ischemia under different brain temperatures.

Under global cerebral ischemia, the effect of different brain temperature on cerebral ischemic injury was studied. Male Sprague-Dawley rats were divided into normothermic (37-38°C) ischemia, mild hypothermic (31-32°C) ischemia, hyperthermic (41-42°C) ischemia and sham-operated groups. Global cerebral ischemia was established using the Pulsinelli four-vessel occlusion model and brain temperature was maintained at defined level for 60 min after 20-min ischemia. The expression of c-fos protein and the levels of malondialdehyde (MDA) and lactate in brain regions were detected by immunochemistry and spectrophotometrical methods, respectively. C-fos positive neurons were found in the hippocampus and cerebral cortex after cerebral ischemia reperfusion. Mild hypothermia increased the expression of c-fos protein in both areas, whereas hyperthermia decreased the expression of c-fos protein in the hippocampus at 24 h reperfusion, and the cerebral cortex at 48 h reperfusion when compared to normothermic conditions. In normothermic, mild hypothermic and hyperthermic ischemia groups, the levels of MDA and lactate in brain tissue were increased at 24, 48 and 72 h reperfusion following 20-min ischemia as compared with the sham-operated group (P<0.01). The levels of MDA and lactate in mild hypothermic group were significantly lower than those in normothermic group (P<0.01). It is suggested that brain temperature influences the translation of the immunoreactive protein product of c-fos after global cerebral ischemia, and MDA and lactate are also affected by hypothermia and hyperthermia.

Sphingosine kinase-1 protects differentiated N2a cells against beta-amyloid25-35-induced neurotoxicity via the mitochondrial pathway.

Although the etiology of Alzheimer's disease (AD) is not fully understood, multiple lines of evidence suggests the importance of amyloid-ß (Aß) in the initiation/progression of the disease. Aß has been shown to induce neuronal apoptosis via the sphingomyelin/ceramide pathway. This study was designed to elucidate whether the sphingosine kinase-1 (SPK1), a critical regulator of the ceramide/sphingosine 1-phosphate rheostat, plays a pivotal role in the regulation of death and survival of differentiated neuro-2a cells in response to beta-amyloid peptide fragment 25-35 (Aß25-35). These results show that the expression of SPK1 was markedly decreased in Aß25-35-induced neurotoxicity, as evidenced by the decreased cell viability and the increased apoptotic rate. Overexpression of SPK1 significantly attenuated Aß25-35-induced neurotoxicity, whereas silencing the expression of SPK1 exacerbated it. Moreover, overexpression of SPK1 can significantly attenuate Aß25-35-induced upregulation of Bax and rehabilitate the level of Bcl-2; concomitantly, it can ameliorate mitochondrial ultrastructure. These studies demonstrate that overexpression of SPK1 may moderate Aß25-35-induced neurotoxicity by regulating the Bcl-2/Bax ratio and improving mitochondrial ultrastructure. Based on these findings, SPK1 is a potential therapeutic target for AD.

Chinese culture permeation in the treatment of Parkinson disease: a cross-sectional study in four regions of China.

BACKGROUND: Little is known about the clinical features and treatment of Chinese patients with Parkinson disease (PD). METHODS: A large cross-sectional survey of clinical features, medication use, and motor complications was conducted in 901 consecutive PD patients, from 42 randomly selected university-affiliated hospitals in four urban economic regions of China, between December 2006 and May 2007. RESULTS: The 901 PD patients had age range 30 to 88, and median disease duration 50 months. Most (737, 81.8%) used L-dopa (median 375 mg/day), and often added low doses of other antiparkinsonian agents. Among L-dopa-treated patients, the prevalence of motor complications was low (dyskinesias: 8.5%; motor fluctuations: 18.6%), even among patients with disease duration ≥11 years (dyskinesias: 18.1%; motor fluctuations: 42.2%). Higher L-dopa use was associated with higher occurrence of dyskinesias (OR 2.44; 95% CI 1.20-5.13) and motor fluctuations (OR 2.48; 95% CI 1.49-4.14). Initiating PD treatment with L-dopa alone (OR 0.46; 95% CI 0.22-0.95) or in combination with other medications (OR 0.41; 95% CI 0.19-0.87) was associated with less dyskinesia than treatment initiated with non-L-dopa medication. CONCLUSIONS: Many Chinese PD patients are treated with low-dose L-dopa and added low-dose antiparkinsonian agents, with a low prevalence of motor complications, which might be influenced by Chinese culture.

Comparative efficacy and acceptability of antidepressants in Parkinson's disease: a network meta-analysis.

BACKGROUND: Depression is a common non-motor symptom in patients with Parkinson's disease (PD). There are many kinds of antidepressants being used, such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and Dopamine agonists which are suggested as alternative antidepressants for the treatment of depression in PD. Which one should we choose first? Literatures have shown inconsistent results. METHODS: We conducted a network meta-analysis of randomized controlled trials to compare the efficacy and acceptability of therapeutic methods for the treatment of depression in Parkinson's disease. RESULTS: We used the odds ratios (OR) as effect size firstly and the results indicated no statistical significance between each compared intervention. Then we used the logarithm of the individual odds ratios as effect size. With efficacy of TCAs as the standard of comparison, the degree of incoherence (a measure of how closely the entire network fits together) was small (ω =  4.824827e-05). The logor were: SSRIs -0.69 (95% CI -1.28- -0.10); Pramipexole -0.73 (-1.71- -0.26); Pergolide -1.97 (-3.67- 0.27); SNRIs -0.86 (-1.86- 0.15); Placebo -1.24 (-1.99- -0.50). With Placebo as the standard of comparison, the logor were: TCAs 1.24 (0.50- 1.99); SSRIs 0.55 (-0.03- 1.13); Pramipexole 0.51 (-0.12- 1.15); Pergolide -0.73 (-2.25- 0.80); SNRIs 0.38 (-0.42- 1.19); TCAs, pramipexole, pergolide and SNRIs showed better profile of acceptability, leading to significant fewer discontinuations than that of SSRIs. CONCLUSIONS: There is insufficient evidence to support antidepressant efficacy for SSRIs, pramipexole, pergolide and SNRIs. TCAs might be the best choice when starting antidepressant treatment in patients of Parkinson's disease because it has the most favorable balance between benefits and acceptability, followed by pramipexole and SNRIs, SSRIs might be the last choice.

Temperature control can abolish anesthesia-induced tau hyperphosphorylation and partly reverse anesthesia-induced cognitive impairment in old mice.

AIMS: Anesthesia is related to cognitive impairment and the risk for Alzheimer's disease. Hypothermia during anesthesia can lead to abnormal hyperphosphorylation of tau, which has been speculated to be involved in anesthesia-induced cognitive impairment. The aim of this study was to investigate whether maintenance of the tau phosphorylation level by body temperature control during anesthesia could reverse the cognitive dysfunction in C57BL/6 mice. METHODS: Eighteen-month-old mice were repeatedly anesthetized during a 2-week period with or without maintenance of body temperature, control mice were treated with normal saline instead of anesthetics. Tau phosphorylation level in mice brain was detected on western blot, and cognitive performance was measured using the Morris water maze (MWM). RESULTS: After anesthesia-induced hypothermia in old mice, tau was hyperphosphorylated and the cognitive performance, measured on MWM, was impaired. When body temperature was controlled during anesthesia, however, the tau hyperphosphorylation was completely avoided, and there was partial recovery in cognitive impairment measured on the MWM. CONCLUSION: Hyperphosphorylation of tau in the brain after anesthesia is an important event, and it might be, although not solely, responsible for postoperative cognitive decline.

Role of ciliary neurotrophic factor in the proliferation and differentiation of neural stem cells.

Ciliary neurotrophic factor (CNTF) is a pleiotropic cytokine that has been fully studied for its structure, receptor, and signaling pathways and its multiplex effects on neural system, skeletal muscle, and weight control. Recent research demonstrates that CNTF also plays an important role in neurogenesis and the differentiation of neural stem cells. In this article, we summarize the general characteristics of CNTF and its function on neural stem cells, which could be a valuable therapeutic strategy in treating neurological disorders.

Aspirin inhibits human telomerase activation in unstable carotid plaques.

The activation of telomerase in unstable plaques is an important factor in atherosclerosis, and may be predictive of the risk of cerebrovascular diseases. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activation. The aim of the present study was to investigate whether aspirin inhibits the activation of telomerase and hTERT in unstable carotid plaques. Polymorphonuclear neutrophils (PMNs) derived from carotid plaques were isolated from the washing medium of angioplasty balloons, while circulating PMNs, isolated from arterial blood, served as the controls. A polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) enzyme-linked immunosorbent assay (ELISA) was used to measure the telomerase activity in the cells following treatment with aspirin. The mRNA and protein expression of hTERT were detected by a reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis, respectively. The results revealed that the atherosclerotic plaques were positive for telomerase activity, and that aspirin inhibited the telomerase activity of the PMNs derived from the plaques. In addition, aspirin was demonstrated to inhibit the mRNA and protein expression of hTERT through the suppression of hTERT transcriptional activity; however, it had no inhibitory effect on the telomerase activity of the circulating PMNs. Thus, the activation of telomerase in resident PMNs is critical in the instability of carotid plaques. The upregulation of telomerase and hTERT during the progression of atherosclerosis may indicate a role for telomerase in the vascular remodeling that occurs during atherogenesis. Aspirin was demonstrated to inhibit the activation of telomerase via an hTERT-dependent manner in the PMN cells of unstable carotid plaques, and thus hTERT may be considered as a target in the treatment of cerebrovascular diseases.

Effects of small interfering RNA targeting sphingosine kinase-1 gene on the animal model of Alzheimer's disease.

Alzheimer's disease (AD) is an age-related, progressive neurodegenerative disorder that occurs gradually and results in memory, behavior, and personality changes. Abnormal sphingolipid metabolism was reported in AD previously. This study aimed to investigate whether sphK1 could exacerbate the accumulation of amyloid protein (Aß) and sharpen the learning and memory ability of the animal model of AD using siRNA interference. An adenovirus vector expressing small interfering RNA (siRNA) against the sphK1 gene (sphK1-siRNA) was designed, and the effects of sphK1-siRNA on the APP/PS1 mouse four weeks after treatment with sphK1-siRNA hippocampal injection were examined. SphK1 protein expression was confirmed by using Western blotting and ceramide content coupled with S1P secretion was evaluated by enzyme-linked immunosorbent assay (ELISA). Aß load was detected by immunohistochemical staining and ELISA. Morris water maze was adopted to test the learning and memory ability of the APP/PS1 mice. A significant difference in the expression of sphK1 protein and mRNA was observed between the siRNA group and the control group. Aß load in transfected mice was accelerated in vivo, with significant aggravation of the learning and memory ability. The sphK1 gene modulation in the Aß load and the learning and memory ability in the animal model of AD may be important for the treatment of AD.

Rapamycin decreases tau phosphorylation at Ser214 through regulation of cAMP-dependent kinase.

Preventing or reducing tau hyperphosphorylation is considered to be a therapeutic strategy in the treatment of Alzheimer's disease (AD). Rapamycin may be a potential therapeutic agent for AD, because the rapamycin-induced autophagy may enhance the clearance of the hyperphosphorylated tau. However, recent rodent studies show that the protective effect of rapamycin may not be limited in the autophagic clearance of the hyperphosphorylated tau. Because some tau-related kinases are targets of the mammalian target of rapamycin (mTOR), we assume that rapamycin may regulate tau phosphorylation by regulating these kinases. Our results showed that in human neuroblastoma SH-SY5Y cells, treatment with rapamycin induced phosphorylation of the type IIα regulatory (RIIα) subunit of cAMP-dependent kinase (PKA). Rapamycin also induced nuclear translocation of the catalytic subunits (Cat) of PKA and decreases in tau phosphorylation at Ser214 (pS214). The above effects of rapamycin were prevented by pretreatment with the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126. In addition, these effects of rapamycin might not depend on the level of tau expression, because similar results were obtained in both the non-tau-expressing wild type human embryonic kidney 293 (HEK293) cells and HEK293 cells stably transfected with the longest isoform of recombinant human tau (tau441; HEK293/tau441). These findings suggest that rapamycin decreases pS214 via regulation of PKA. Because tau phosphorylation at Ser214 may prime tau for further phosphorylation by other kinases, our findings provide a novel possible mechanism by which rapamycin reduces or prevents tau hyperphosphorylation.

Pretreatment of PC12 cells with 17ß-estradiol prevents Aß-induced down-regulation of CREB phosphorylation and prolongs inhibition of GSK-3ß.

It is believed that estrogen protects neurons against various toxicities like that from amyloid ß (Aß) in Alzheimer's disease (AD). In the present study, we investigated the effects of Aß1-42 on the activities of cyclic-AMP response element-binding protein (CREB) and glycogen synthase kinase-3ß (GSK-3ß), two key proteins associated with learning and memory, and the effects of 17ß-estradiol on Aß(1-42)-induced changes of CREB and GSK-3ß in PC12 cells. We found that Aß1-42 induced a decrease in phosphorylation of CREB at Ser133 (CREB pS133) and caused a transient (30 min) up-regulation of the inhibitory GSK-3ß phosphorylation at Ser9 (GSK-3ß pS9), followed by down-regulation of GSK-3ß pS9. Pretreatment of 17ß-estradiol is needed for its protection against Aß1-42-induced changes of CREB. The protective role of 17ß-estradiol against Aß(1-42)-induced down-regulation of CREB pS133 was abolished by the mitogen-activated protein kinase (MAPK) pathway inhibitor U0126. Furthermore, 17ß-estradiol also prolonged the up-regulation of GSK-3ß pS9 for at least 8 h. However, this action of 17ß-estradiol was abrogated by PKA inhibitor H-89, AKT inhibitor LY294002, and MAPK inhibitor U0126. These results suggest that, while the protection of 17ß-estradiol on CREB is MAPK dependent, its effect on GSK-3ß integrates several pathways. These studies provide new insights into the role of estrogen in memory and AD.

A non-transgenic mouse model (icv-STZ mouse) of Alzheimer's disease: similarities to and differences from the transgenic model (3xTg-AD mouse).

Alzheimer's disease (AD) can be divided into sporadic AD (SAD) and familial AD (FAD). Most AD cases are sporadic and result from multiple etiologic factors, including environmental, genetic, and metabolic factors, whereas FAD is caused by mutations in the presenilins or amyloid-ß (Aß) precursor protein (APP) genes. A commonly used animal model for AD is the 3xTg-AD transgenic mouse model, which harbors mutated presenilin 1, APP, and tau genes and thus represents a model of FAD. There is an unmet need in the field to characterize animal models representing different AD mechanisms, so that potential drugs for SAD can be evaluated preclinically in these animal models. A mouse model generated by intracerebroventricular (icv) administration of streptozocin (STZ), the icv-STZ mouse, shows many aspects of SAD. In this study, we compared the non-cognitive and cognitive behaviors as well as biochemical and immunohistochemical alterations between the icv-STZ mouse and the 3xTg-AD mouse. We found that both mouse models showed increased exploratory activity as well as impaired learning and spatial memory. Both models also demonstrated neuroinflammation, altered synaptic proteins and insulin/IGF-1 (insulin-like growth factor-1) signaling, and increased hyperphosphorylated tau in the brain. The most prominent brain abnormality in the icv-STZ mouse was neuroinflammation, and in the 3xTg-AD mouse it was elevation of hyperphosphorylated tau. These observations demonstrate the behavioral and neuropathological similarities and differences between the icv-STZ mouse and the 3xTg-AD mouse models and will help guide future studies using these two mouse models for the development of AD drugs.

Influence of endogenous ciliary neurotrophic factor on neural differentiation of adult rat hippocampal progenitors.

Ciliary neurotrophic factor is the only known neurotrophic factor that can promote differentiation of hippocampal neural progenitor cells to glial cells and neurons in adult rats. This process is similar to spontaneous differentiation. Therefore, ciliary neurotrophic factor may be involved in spontaneous differentiation of neural stem cells. To verify this hypothesis, the present study isolated neural progenitor cells from adult male rats and cultured them in vitro. Results showed that when neural progenitor cells were cultured in the absence of mitogen fibroblast growth factor-2 or epidermal growth factor, they underwent spontaneous differentiation into neurons and glial cells. Western blot and immunocytochemical staining showed that exogenous ciliary neurotrophic factor strongly induced adult hippocampal progenitor cells to differentiate into neurons and glial cells. Moreover, passage 4 adult hippocampal progenitor cells expressed high levels of endogenous ciliary neurotrophic factor, and a neutralizing antibody against ciliary neurotrophic factor prevented the spontaneous neuronal and glial differentiation of adult hippocampal progenitor cells. These results suggest that the spontaneous differentiation of adult hippocampal progenitor cells is mediated partially by endogenous ciliary neurotrophic factor.