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Neurobiology of Disease Aug 2024Parkinson's disease is caused by a selective vulnerability and cell loss of dopaminergic neurons of the Substantia Nigra pars compacta and, consequently, striatal...
Parkinson's disease is caused by a selective vulnerability and cell loss of dopaminergic neurons of the Substantia Nigra pars compacta and, consequently, striatal dopamine depletion. In Parkinson's disease therapy, dopamine loss is counteracted by the administration of L-DOPA, which is initially effective in ameliorating motor symptoms, but over time leads to a burdening side effect of uncontrollable jerky movements, termed L-DOPA-induced dyskinesia. To date, no efficient treatment for dyskinesia exists. The dopaminergic and serotonergic systems are intrinsically linked, and in recent years, a role has been established for pre-synaptic 5-HT1a/b receptors in L-DOPA-induced dyskinesia. We hypothesized that post-synaptic serotonin receptors may have a role and investigated the effect of modulation of 5-HT4 receptor on motor symptoms and L-DOPA-induced dyskinesia in the unilateral 6-OHDA mouse model of Parkinson's disease. Administration of RS 67333, a 5-HT4 receptor partial agonist, reduces L-DOPA-induced dyskinesia without altering L-DOPA's pro-kinetic effect. In the dorsolateral striatum, we find 5-HT4 receptor to be predominantly expressed in D2R-containing medium spiny neurons, and its expression is altered by dopamine depletion and L-DOPA treatment. We further show that 5-HT4 receptor agonism not only reduces L-DOPA-induced dyskinesia, but also enhances the activation of the cAMP-PKA pathway in striatopallidal medium spiny neurons. Taken together, our findings suggest that agonism of the post-synaptic serotonin receptor 5-HT4 may be a novel therapeutic approach to reduce L-DOPA-induced dyskinesia.
Topics: Animals; Dyskinesia, Drug-Induced; Levodopa; Oxidopamine; Mice; Male; Mice, Inbred C57BL; Serotonin 5-HT4 Receptor Agonists; Antiparkinson Agents; Corpus Striatum; Receptors, Serotonin, 5-HT4; Parkinsonian Disorders; Pyridines; Neurons; Piperidines; Pyrimidines
PubMed: 38852753
DOI: 10.1016/j.nbd.2024.106559 -
ACS Chemical Neuroscience Aug 2023Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration, resulting in dopamine depletion and motor behavior deficits. Since the discovery of L-DOPA,... (Review)
Review
Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration, resulting in dopamine depletion and motor behavior deficits. Since the discovery of L-DOPA, it has been the most prescribed drug for symptomatic relief in PD, whose prolonged use, however, causes undesirable motor fluctuations like dyskinesia and dystonia. Further, therapeutics targeting the pathological hallmarks of PD including α-synuclein aggregation, oxidative stress, neuroinflammation, and autophagy impairment have also been developed, yet PD treatment is a largely unmet success. The inception of the nanovesicle-based drug delivery approach over the past few decades brings add-on advantages to the therapeutic strategies for PD treatment in which nanovesicles (basically phospholipid-containing artificial structures) are used to load and deliver drugs to the target site of the body. The present review narrates the characteristic features of nanovesicles including their blood-brain barrier permeability and ability to reach dopaminergic neurons of the brain and finally discusses the current status of this technology in the treatment of PD. From the review, it becomes evident that with the assistance of nanovesicle technology, the therapeutic efficacy of anti-PD pharmaceuticals, phyto-compounds, as well as that of nucleic acids targeting α-synuclein aggregation gained a significant increment. Furthermore, owing to the multiple drug-carrying abilities of nanovesicles, combination therapy targeting multiple pathogenic events of PD has also found success in preclinical studies and will plausibly lead to effective treatment strategies in the near future.
Topics: Humans; Parkinson Disease; alpha-Synuclein; Dopamine; Levodopa; Brain; Dopaminergic Neurons
PubMed: 37534999
DOI: 10.1021/acschemneuro.3c00070 -
Heliyon Aug 2023Growth hormone stimulation tests (GHST) remain the cornerstone for diagnosing growth hormone deficiency (GHD), yet they can be lengthy and costly. We aimed to examine...
INTRODUCTION
Growth hormone stimulation tests (GHST) remain the cornerstone for diagnosing growth hormone deficiency (GHD), yet they can be lengthy and costly. We aimed to examine whether the combined clonidine and glucagon stimulation test (CGST) and l-dopa and glucagon stimulation test (LDGST) can be shortened without compromising the test's specificity.
MATERIAL AND METHODS
We retrospectively analyzed the baseline characteristics, auxological and laboratory data of children with short stature who had undergone a CGST and an LDGST for GHD. We compared the diagnostic accuracy for the standard test and shortened test, eliminating time points of 0 and 210 min.
RESULTS
We reviewed 830 charts (8.17 ± 2.92 years old; 56.27% males), with 431 (57.0%) children in the CGST group, and 38 (51.35%) in the LDGST group who tested negative for GHD. The peak and maximum GH levels occurred at the 60-min time point for both the CGST and LDGST. Eliminating the 0-min time point was the only time that did not affect the specificity of the CGST, with a false-positive rate of 2 (2.99%), specificity of 0.99 (0.99-0.99), and p value of 0.25. Eliminating the 0- and 210-min time points did not affect the specificity of the LDGST, with a false-positive rate of 2 (5.26%), specificity of 0.95 (0.95-0.95), and p value of 0.24.
CONCLUSIONS
We concluded that 0-min time point could be eliminated without compromising the combined GHST diagnostic value, thus resulting in cost reduction. Larger studies are needed for the combined LDGST to explore whether the 30- and 210-min time points could be eliminated, thus resulting in cost and time savings.
PubMed: 37560690
DOI: 10.1016/j.heliyon.2023.e18713 -
CNS Neuroscience & Therapeutics Feb 2024Tyrosine decarboxylase (TDC) presented in the gut-associated strain Enterococcus faecalis can convert levodopa (L-dopa) into dopamine (DA), and its increased abundance...
AIM
Tyrosine decarboxylase (TDC) presented in the gut-associated strain Enterococcus faecalis can convert levodopa (L-dopa) into dopamine (DA), and its increased abundance would potentially minimize the availability and efficacy of L-dopa. However, the known human decarboxylase inhibitors are ineffective in this bacteria-mediated conversion. This study aims to investigate the inhibition of piperine (PIP) on L-dopa bacterial metabolism and evaluates the synergistic effect of PIP combined with L-dopa on Parkinson's disease (PD).
METHODS
Metagenomics sequencing was adopted to determine the regulation of PIP on rat intestinal microbiota structure, especially on the relative abundance of E. faecalis. Then, the inhibitory effects of PIP on L-dopa conversion and TDC expression of E. faecalis were tested in vitro. We examined the synergetic effect of the combination of L-dopa and PIP on 6-hydroxydopamine (6-OHDA)-lesioned rats and tested the regulations of L-dopa bioavailability and brain DA level by pharmacokinetics study and MALDI-MS imaging. Finally, we evaluated the microbiota-dependent improvement effect of PIP on L-dopa availability using pseudo-germ-free and E. faecalis-transplanted rats.
RESULTS
We found that PIP combined with L-dopa could better ameliorate the move disorders of 6-OHDA-lesioned rats by remarkably improving L-dopa availability and brain DA level than L-dopa alone, which was associated with the effect of PIP on suppressing the bacterial decarboxylation of L-dopa via effectively downregulating the abnormal high abundances of E. faecalis and TDC in 6-OHDA-lesioned rats.
CONCLUSION
Oral administration of L-dopa combined with PIP can improve L-dopa availability and brain DA level in 6-OHDA-lesioned rats by suppressing intestinal bacterial TDC.
Topics: Humans; Rats; Animals; Levodopa; Parkinson Disease; Oxidopamine; Tyrosine Decarboxylase; Gastrointestinal Microbiome; Dopamine; Bacteria; Antiparkinson Agents; Disease Models, Animal; Alkaloids; Piperidines; Benzodioxoles; Polyunsaturated Alkamides
PubMed: 37528534
DOI: 10.1111/cns.14383 -
European Journal of Pharmacology Sep 2023Compared with levodopa, dopamine agonists (DAs) as initial treatment are associated with lower incidences of motor complications in early Parkinson's disease (PD). There... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Compared with levodopa, dopamine agonists (DAs) as initial treatment are associated with lower incidences of motor complications in early Parkinson's disease (PD). There is no strong evidence that a given DA is more potent in lower incidences of motor complications than another.
OBJECTIVE
We performed a network meta-analysis of levodopa versus DAs as monotherapy in early PD to access the risk of motor complications.
METHODS
Databases were searched up to June 2022 for eligible RCTs. Levodopa and four DAs (pramipexole, ropinirole, bromocriptine and pergolide) were investigated. The incidences of motor complications and efficacy, tolerability and safety outcomes were analyzed.
RESULTS
Nine RCTs (2112 patients) were included in the current study. The surface under the cumulative ranking curve (SUCRA) indicated that levodopa ranked first in the incidence of dyskinesia (0.988), followed by pergolide, pramipexole, ropinirole, and bromocriptine (0.704, 0.408, 0.240, 0.160). Pramipexole was least prone to wearing-off (0.109) and on-off fluctuation (0.041). Levodopa performed best in improvements of UPDRS-II, UPDRS-III, and UPDRS-II + III (0.925, 0.952, 0.934). Bromocriptine ranked first in total withdrawals and withdrawals due to adverse events (0.736, 0.751). Four DAs showed different adverse events profiles.
CONCLUSION
In the two non-ergot DAs, ropinirole is associated with a lower risk of dyskinesia while pramipexole is associated with lower risks of wearing-off and on-off fluctuations. Our research may facilitate head-to-head research, larger sample sizes, long following-up time RCTs to confirm the findings of this network meta-analysis.
Topics: Humans; Levodopa; Dopamine Agonists; Bromocriptine; Antiparkinson Agents; Parkinson Disease; Pramipexole; Pergolide; Network Meta-Analysis; Dyskinesias
PubMed: 37385577
DOI: 10.1016/j.ejphar.2023.175884 -
CNS Neuroscience & Therapeutics Oct 2023Levodopa (L-DOPA) is considered the most reliable drug for treating Parkinson's disease (PD) clinical symptoms. Regrettably, long-term L-DOPA therapy results in the...
BACKGROUND
Levodopa (L-DOPA) is considered the most reliable drug for treating Parkinson's disease (PD) clinical symptoms. Regrettably, long-term L-DOPA therapy results in the emergence of drug-induced abnormal involuntary movements (AIMs) in most PD patients. The mechanisms underlying motor fluctuations and dyskinesia induced by L-DOPA (LID) are still perplexing.
METHODS
Here, we first performed the analysis on the microarray data set (GSE55096) from the gene expression omnibus (GEO) repository and identified the differentially expressed genes (DEGs) using linear models for microarray analysis (Limma) R packages from the Bioconductor project. 12 genes (Nr4a2, Areg, Tinf2, Ptgs2, Pdlim1, Tes, Irf6, Tgfb1, Serpinb2, Lipg, Creb3l1, Lypd1) were found to be upregulated. Six genes were validated on quantitative polymerase chain reaction and subsequently, Amphiregulin (Areg) was selected (based on log2 fold change) for further experiments to unravel its involvement in LID. Areg LV_shRNA was used to knock down Areg to explore its therapeutic role in the LID model.
RESULTS
Western blotting and immunofluorescence results show that AREG is significantly expressed in the LID group relative to the control. Dyskinetic movements in LID mice were alleviated by Areg knockdown, and the protein expression of delta FOSB, the commonly attributable protein in LID, was decreased. Moreover, Areg knockdown reduced the protein expression of P-ERK. In order to ascertain whether the inhibition of the ERK pathway (a common pathway known to mediate levodopa-induced dyskinesia) could also impede Areg, the animals were injected with an ERK inhibitor (PD98059). Afterward, the AIMs, AREG, and ERK protein expression were measured relative to the control group. A group treated with ERK inhibitor had a significant decrease of AREG and phosphorylated ERK protein expression relative to the control group.
CONCLUSION
Taken together, our results indicate unequivocal involvement of Areg in levodopa-induced dyskinesia, thus a target for therapy development.
Topics: Mice; Animals; Levodopa; Parkinson Disease; Oxidopamine; Antiparkinson Agents; Amphiregulin; Dyskinesia, Drug-Induced; Disease Models, Animal
PubMed: 37101388
DOI: 10.1111/cns.14229 -
Pregnancy Hypertension Dec 2023Consensus on the relative efficacy of available antihypertensive agents used in pregnancy is lacking. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Consensus on the relative efficacy of available antihypertensive agents used in pregnancy is lacking.
OBJECTIVE
To compare treatment success with antihypertensives and categorize by route of administration.
SEARCH STRATEGY
MEDLINE, Embase, PubMed, Web of Science, Scopus, CINAHL, and clinicaltrials.gov were searched without date restriction.
DATA COLLECTION
Peer-reviewed randomized controlled trials (RCTs) comparing pharmacologic agents used to treat hypertension in parturients were included. Evaluated treatment groups included IV-labetalol (BBIV), IV-hydralazine (DIV), oral-nifedipine (CCBPO), sublingual nifedipine (CCBSL), IV-calcium channel blocker (nonspecific)(CCBIV), IV-nitroglycerine (NTG), epoprostenol infusion (PRO), IV-ketanserin (5HT2B), IV-diazoxide (BZO), oral-nifedipine + methyldopa (CCBAG), oral-methyl-dopa (AAG), and oral prazosin (ABPO).
ANALYSIS
Seventy-four studies (8324 patients) were eligible post PRISMA guidelines screening. Results were pooled using a Bayesian-approach for success of treatment (study defined target blood pressure), time to achieve target pressure, and neonatal intensive-care admissions.
RESULTS
Treatment success (primary outcome, 55 trials with 5518 patients) was analyzed. Surface under the cumulative ranking curve (SUCRA) was categorized for 13 drugs, CCBPO (0.84) followed by CCBSL (0.78) were most likely to be effective in achieving target blood pressure. After sub-grouping by presence/absence of preeclampsia, CCB-PO ranked highest for both [(0.82) vs. (0.77), respectively]. Serotonin antagonists (0.99) and nitroglycerin (0.88) ranked highest for time to target pressure. NICU admissions were lowest for alpha-2 agonists (0.89), followed by BB PO (0.82) and hydralazine IV (0.49).
CONCLUSION
Oral calcium-channel blockers ranked highest for treatment success. Ketanserin achieved target blood pressure fastest, warranting additional research. The results should be interpreted with caution as SUCRA values may not indicate whether the differences between interventions have clinically meaningful effect sizes.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Antihypertensive Agents; Calcium Channel Blockers; Hydralazine; Hypertension; Ketanserin; Methyldopa; Network Meta-Analysis; Nifedipine; Pre-Eclampsia; Randomized Controlled Trials as Topic
PubMed: 37857042
DOI: 10.1016/j.preghy.2023.10.005 -
Journal of Neural Transmission (Vienna,... Nov 2023Continuous drug delivery (CDD) has emerged as a feasible and pragmatic therapeutic option for dopamine replacement therapy in advanced Parkinson's disease (PD). CDD aims... (Review)
Review
Continuous drug delivery (CDD) has emerged as a feasible and pragmatic therapeutic option for dopamine replacement therapy in advanced Parkinson's disease (PD). CDD aims to mimic the physiological tonic dopamine release from striatal dopaminergic neurons and thus reduces the severity and duration of motor and non-motor fluctuations partly related to pulsatile levodopa stimulation. Non-motor symptoms and fluctuations are ubiquitous in PD and include sleep dysfunction, a problem that occurs in over 90% of PD patients across all stages, from prodromal to palliative. In this review, we discuss the currently available and in development non-oral dopaminergic CDD strategies with a focus on their efficacy in the treatment of the burdensome sleep dysfunction in PD.
Topics: Humans; Parkinson Disease; Antiparkinson Agents; Dopamine; Levodopa; Sleep Wake Disorders; Sleep
PubMed: 37126118
DOI: 10.1007/s00702-023-02640-7 -
The Analyst Jul 2023Melanin nanoparticles (NPs) have important biological functions including photoprotection and colouration, and artificial melanin-like NPs are relevant for catalysis,...
Melanin nanoparticles (NPs) have important biological functions including photoprotection and colouration, and artificial melanin-like NPs are relevant for catalysis, drug delivery, diagnosis and therapy. Despite their importance, the optical properties of single melanin NPs have not been measured. We combine quantitative differential interference contrast (qDIC) and extinction microscopy to characterise the optical properties of single NPs, both naturally sourced from cuttlefish ink, as well as synthetic NPs using polydopamine (PDA) and L-3,4-dihydroxyphenylalanine (L-DOPA). Combining qDIC with extinction, we determine the absorption index of individual NPs. We find that on average the natural melanin NPs have a higher absorption index than the artificial melanin NPs. From the analysis of the polarisation-dependent NP extinction, the NP aspect ratio is determined, with mean values at 405 nm wavelength in agreement with transmission electron microscopy. At longer wavelengths, we observe an additional optical anisotropy which is attributed to dichroism by structural ordering of the melanin. Our quantitative analysis yields a dichroism of 2-10% of the absorption index, increasing with wavelength from 455 nm to 660 nm for L-DOPA and PDA. Such an in-depth quantification of the optical properties of single melanin NPs is important for the design and future application of these ubiquitous bionanomaterials.
Topics: Melanins; Levodopa; Nanoparticles
PubMed: 37382583
DOI: 10.1039/d3an00654a -
Brain Research Jul 2023L-DOPA is the standard treatment for Parkinson's disease (PD), but chronic treatment typically leads to L-DOPA-induced dyskinesia (LID). LID involves a complex...
L-DOPA is the standard treatment for Parkinson's disease (PD), but chronic treatment typically leads to L-DOPA-induced dyskinesia (LID). LID involves a complex interaction between the remaining dopamine (DA) system and the semi-homologous serotonin (5-HT) system. Since serotonin transporters (SERT) have some affinity for DA uptake, they may serve as a functional compensatory mechanism when DA transporters (DAT) are scant. DAT and SERT's functional contributions in the dyskinetic brain have not been well delineated. The current investigation sought to determine how DA depletion and L-DOPA treatment affect DAT and SERT transcriptional processes, translational processes, and functional DA uptake in the 6-hydroxydopamine-lesioned hemi-parkinsonian rat. Rats were counterbalanced for motor impairment into equally lesioned treatment groups then given daily L-DOPA (0 or 6 mg/kg) for 2 weeks. At the end of treatment, the substantia nigra was processed for tyrosine hydroxylase (TH) and DAT gene expression and dorsal raphe was processed for SERT gene expression. The striatum was processed for synaptosomal DAT and SERT protein expression and ex vivo DA uptake. Nigrostriatal DA loss severely reduced DAT mRNA and protein expression in the striatum with minimal changes in SERT. L-DOPA treatment, while not significantly affecting DAT or SERT alone, did increase striatal SERT:DAT protein ratios. Using ex vivo microdialysis, L-DOPA treatment increased DA uptake via SERT when DAT was depleted. Overall, these results suggest that DA loss and L-DOPA treatment uniquely alter DAT and SERT, revealing implications for monoamine transporters as potential biomarkers and therapeutic targets in the hemi-parkinsonian model and dyskinetic PD patients.
Topics: Rats; Animals; Levodopa; Serotonin Plasma Membrane Transport Proteins; Serotonin; Gain of Function Mutation; Rats, Sprague-Dawley; Dopamine; Corpus Striatum; Parkinson Disease; Oxidopamine
PubMed: 37127174
DOI: 10.1016/j.brainres.2023.148381