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Signal Transduction and Targeted Therapy Feb 2021The phenylalanine-tyrosine-dopa-dopamine pathway provides dopamine to the brain. In this process, tyrosine hydroxylase (TH) is the rate-limiting enzyme that hydroxylates...
The phenylalanine-tyrosine-dopa-dopamine pathway provides dopamine to the brain. In this process, tyrosine hydroxylase (TH) is the rate-limiting enzyme that hydroxylates tyrosine and generates levodopa (L-dopa) with tetrahydrobiopterin (BH) as a coenzyme. Here, we show that oral berberine (BBR) might supply H through dihydroberberine (reduced BBR produced by bacterial nitroreductase) and promote the production of BH from dihydrobiopterin; the increased BH enhances TH activity, which accelerates the production of L-dopa by the gut bacteria. Oral BBR acts in a way similar to vitamins. The L-dopa produced by the intestinal bacteria enters the brain through the circulation and is transformed to dopamine. To verify the gut-brain dialog activated by BBR's effect, Enterococcus faecalis or Enterococcus faecium was transplanted into Parkinson's disease (PD) mice. The bacteria significantly increased brain dopamine and ameliorated PD manifestation in mice; additionally, combination of BBR with bacteria showed better therapeutic effect than that with bacteria alone. Moreover, 2,4,6-trimethyl-pyranylium tetrafluoroborate (TMP-TFB)-derivatized matrix-assisted laser desorption mass spectrometry (MALDI-MS) imaging of dopamine identified elevated striatal dopamine levels in mouse brains with oral Enterococcus, and BBR strengthened the imaging intensity of brain dopamine. These results demonstrated that BBR was an agonist of TH in Enterococcus and could lead to the production of L-dopa in the gut. Furthermore, a study of 28 patients with hyperlipidemia confirmed that oral BBR increased blood/fecal L-dopa by the intestinal bacteria. Hence, BBR might improve the brain function by upregulating the biosynthesis of L-dopa in the gut microbiota through a vitamin-like effect.
Topics: Animals; Berberine; Corpus Striatum; Dihydroxyphenylalanine; Dopamine; Enterococcus faecalis; Enterococcus faecium; Gastrointestinal Microbiome; Humans; Levodopa; Mice; Parkinson Disease; Tyrosine 3-Monooxygenase
PubMed: 33623004
DOI: 10.1038/s41392-020-00456-5 -
Annals of Neurology Jul 2021The aim was to demonstrate that continuous s.c. infusion of a soluble levodopa (LD)/carbidopa (CD) phosphate prodrug combination effectively delivers stable LD exposure...
OBJECTIVE
The aim was to demonstrate that continuous s.c. infusion of a soluble levodopa (LD)/carbidopa (CD) phosphate prodrug combination effectively delivers stable LD exposure via a minimally invasive and convenient mode and has the potential to treat Parkinson's disease (PD) patients who are not well controlled on oral medication.
METHODS
Foslevodopa and foscarbidopa were prepared and the equilibrium solubility and chemical stability examined in aqueous media with different values of pH. Solutions of foslevodopa/foscarbidopa (ratios ranging from 4:1 to 20:1) were prepared by dissolving pH-adjusted lyophilized materials in water and infused s.c. in healthy volunteers for ≤72 hours. Frequent blood samples were collected to measure LD and CD exposure, and safety was monitored throughout the study.
RESULTS
Foslevodopa/foscarbidopa (ABBV-951) demonstrates high water solubility and excellent chemical stability near physiological pH, enabling continuous s.c. infusion therapy. After s.c. infusion, a stable LD pharmacokinetic (PK) profile was maintained for ≤72 hours, and the infusion was well tolerated.
INTERPRETATION
Preparation of foslevodopa and foscarbidopa enables preclinical and clinical PK, safety, and tolerability studies in support of their advancement for the treatment of PD. In phase 1 clinical trials, foslevodopa/foscarbidopa demonstrates consistent and stable LD plasma exposure, supporting further studies of this treatment as a potentially transformational option for those suffering from PD. ANN NEUROL 2021;90:52-61.
Topics: Antiparkinson Agents; Carbidopa; Drug Combinations; Humans; Levodopa; Parkinson Disease
PubMed: 33772855
DOI: 10.1002/ana.26073 -
Journal of Parkinson's Disease 2021ND0612 is a continuous, subcutaneous levodopa/carbidopa delivery system in development for patients with Parkinson's disease (PD) experiencing motor... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
ND0612 is a continuous, subcutaneous levodopa/carbidopa delivery system in development for patients with Parkinson's disease (PD) experiencing motor fluctuationsObjective:Evaluate the efficacy and safety of two ND0612 dosing regimens in patients with PD.
METHODS
This was a 28-day open-label study (NCT02577523) in PD patients with ≥2.5 hours/day of OFF time despite optimized treatment. Patients were randomized to treatment with either a 24-hour infusion (levodopa/carbidopa dose of 720/90 mg) or a 14-hour 'waking-day' infusion (levodopa/carbidopa dose of 538/68 mg plus a morning oral dose of 150/15 mg). Supplemental oral doses of levodopa were permitted for patients in both groups if required. In-clinic assessments of OFF time (primary endpoint) and ON time with or without dyskinesia were determined by a blinded rater over 8 hours (normalized to 16 hours).
RESULTS
A total of 38 patients were randomized and 33 (87%) completed the study. Compared to baseline, OFF time for the overall population was reduced by a least squares (LS) mean[95% CI] of 2.0[- 3.3, - 0.7] hours (p = 0.003). ON time with no/mild dyskinesia (no troublesome dyskinesia) was increased from baseline by a LS mean of 3.3[2.0, 4.6] hours (p < 0.0001), and ON time with moderate/severe dyskinesia was reduced by a LS mean of 1.2[- 1.8, - 0.5] hours (p≤0.001). Reduction in OFF time was larger in the 24-hour group (- 2.8[- 4.6, - 0.9] hours; p = 0.004) than in the 14-hour group (- 1.3[- 3.1, 0.5] hours; p = 0.16). Complete resolution of OFF time was observed in 42% (n = 8) of patients in the 24-hour group. Infusion site reactions were the most common adverse event.
CONCLUSION
This study demonstrates the feasibility and safety of continuous subcutaneous delivery of levodopa as a treatment for PD and provides preliminary evidence of efficacy.
Topics: Aged; Antiparkinson Agents; Carbidopa; Drug Combinations; Dyskinesia, Drug-Induced; Feasibility Studies; Female; Humans; Infusions, Parenteral; Levodopa; Male; Middle Aged; Outcome Assessment, Health Care; Parkinson Disease; Severity of Illness Index; Single-Blind Method
PubMed: 33164945
DOI: 10.3233/JPD-202285 -
Molecular Psychiatry Oct 2022Increased inflammation in major depressive disorder (MDD) has been associated with low functional connectivity (FC) in corticostriatal reward circuits and symptoms of... (Randomized Controlled Trial)
Randomized Controlled Trial
Functional connectivity in reward circuitry and symptoms of anhedonia as therapeutic targets in depression with high inflammation: evidence from a dopamine challenge study.
Increased inflammation in major depressive disorder (MDD) has been associated with low functional connectivity (FC) in corticostriatal reward circuits and symptoms of anhedonia, relationships which may involve the impact of inflammation on synthesis and release of dopamine. To test this hypothesis while establishing a platform to examine target engagement of potential therapies in patients with increased inflammation, medically stable unmedicated adult MDD outpatients enrolled to have a range of inflammation (as indexed by plasma C-reactive protein [CRP] levels) were studied at two visits involving acute challenge with the dopamine precursor levodopa (L-DOPA; 250 mg) and placebo (double-blind, randomized order ~1-week apart). The primary outcome of resting-state (rs)FC in a classic ventral striatum to ventromedial prefrontal cortex reward circuit was calculated using a targeted, a priori approach. Data available both pre- and post-challenge (n = 31/40) established stability of rsFC across visits and determined CRP > 2 mg/L as a cut-point for patients exhibiting positive FC responses (post minus pre) to L-DOPA versus placebo (p < 0.01). Higher post-L-DOPA FC in patients with CRP > 2 mg/L was confirmed in all patients (n = 40) where rsFC data were available post-challenge (B = 0.15, p = 0.006), and in those with task-based (tb)FC during reward anticipation (B = 0.15, p = 0.013). While effort-based motivation outside the scanner positively correlated with rsFC independent of treatment or CRP, change in anhedonia scores negatively correlated with rsFC after L-DOPA only in patients with CRP > 2 mg/L (r = -0.56, p = 0.012). FC in reward circuitry should be further validated in larger samples as a biomarker of target engagement for potential treatments including dopaminergic agents in MDD patients with increased inflammation.
Topics: Adult; Humans; Anhedonia; Dopamine; Depressive Disorder, Major; Neural Pathways; Depression; Levodopa; Magnetic Resonance Imaging; Reward; Inflammation
PubMed: 35927580
DOI: 10.1038/s41380-022-01715-3 -
Journal of Controlled Release :... Aug 2023Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) resulting in... (Review)
Review
Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) resulting in dopamine (DA) deficiency, which manifests itself in motor symptoms including tremors, rigidity and bradykinesia. Current PD treatments aim at symptom reduction through oral delivery of levodopa (L-DOPA), a precursor of DA. However, L-DOPA delivery to the brain is inefficient and increased dosages are required as the disease progresses, resulting in serious side effects like dyskinesias. To improve PD treatment efficacy and to reduce side effects, recent research focuses on the encapsulation of L-DOPA into polymeric- and lipid-based nanoparticles (NPs). These formulations can protect L-DOPA from systemic decarboxylation into DA and improve L-DOPA delivery to the central nervous system. Additionally, NPs can be modified with proteins, peptides and antibodies specifically targeting the blood-brain barrier (BBB), thereby reducing required dosages and free systemic DA. Alternative delivery approaches for NP-encapsulated L-DOPA include intravenous (IV) administration, transdermal delivery using adhesive patches and direct intranasal administration, facilitating increased therapeutic DA concentrations in the brain. This review provides an overview of the recent advances for NP-mediated L-DOPA delivery to the brain, and debates challenges and future perspectives on the field.
Topics: Humans; Levodopa; Parkinson Disease; Dopamine; Brain; Nanoparticles
PubMed: 37343725
DOI: 10.1016/j.jconrel.2023.06.026 -
Neurobiology of Disease Jun 2022Glutamatergic hyperactivity in the nucleus striatum, the main basal ganglia input, has been involved in the progression of Parkinson's disease (PD) and the onset of... (Review)
Review
Glutamatergic hyperactivity in the nucleus striatum, the main basal ganglia input, has been involved in the progression of Parkinson's disease (PD) and the onset of L-Dopa-induced dyskinesias (LIDs). Abnormalities in the spiny projection neurons excitability and firing, and in the overactivity of glutamate transmission found in animal models of PD, pointed to the synaptic dysfunctions as a primary target to counteract alterations before overt neurodegeneration, conferring a key role to striatal glutamatergic transmission in the early phases of the disease. The present paper provides an overview of the evidence that glutamatergic overactivity is a critical mechanism underlying different PD-associated striatal alterations in early and advanced symptomatic stages of the disease. These aberrant changes, under L-Dopa therapy, lead to a more complex synaptopathy that involves other neurotransmitter systems and persistent modifications to generate LIDs. The review discusses the main changes in glutamatergic functions found in PD preclinical models and clinical studies and an update of the current pharmacological strategies to modulate the glutamatergic systems at the pre- and postsynaptic levels will be provided.
Topics: Animals; Basal Ganglia; Corpus Striatum; Levodopa; Neostriatum; Parkinson Disease
PubMed: 35314319
DOI: 10.1016/j.nbd.2022.105697 -
The European Journal of Neuroscience Apr 2021Dopamine replacement therapy with L-DOPA remains the most widely prescribed treatment for Parkinson disease. However, prolonged treatment due to disease progression... (Review)
Review
Dopamine replacement therapy with L-DOPA remains the most widely prescribed treatment for Parkinson disease. However, prolonged treatment due to disease progression frequently causes unwanted motor movements known as levodopa-induced dyskinesias. Previous studies have established that alterations to the efferent circuitry of the striatum, a principal component of the basal ganglia, are in part responsible for the pathological motor consequences of prolonged levodopa treatment. While the role of the striatal direct pathway is widely accepted, the engagement of the striatal indirect pathway in dyskinetic pathophysiology is still under consideration. However, recent investigations have finally shown that the activity of both striatal pathways changes as a consequence of dopamine depletion and dyskinetic behavioural conditions. In addition, it has been reported that drug-induced structural alterations to indirect pathway medium spiny neurons, together with associated changes in synaptic plasticity and firing patterns, could contribute importantly to the development of dyskinesia. These findings, together with recent opto- and chemogenetic studies, suggest that a critical imbalance in the activity between both striatal pathways is sufficient to cause dyskinesia in both rodent and primate models of Parkinson disease. In animal models, and in human patients, dyskinetic behaviours elicited by this efferent pathway imbalance can be achieved even in the absence of dopamine denervation. In this review, we summarize recent and past findings to better understand this complex pathology with the aim of pursuing specific cell-type therapies to re-balance efferent striatal activity.
Topics: Animals; Antiparkinson Agents; Basal Ganglia; Corpus Striatum; Disease Models, Animal; Dopamine; Dyskinesias; Humans; Levodopa
PubMed: 32394612
DOI: 10.1111/ejn.14777 -
Biomolecules May 2023Current pharmacotherapy has limited efficacy and/or intolerable side effects in late-stage Parkinson's disease (LsPD) patients whose daily life depends primarily on... (Randomized Controlled Trial)
Randomized Controlled Trial
Current pharmacotherapy has limited efficacy and/or intolerable side effects in late-stage Parkinson's disease (LsPD) patients whose daily life depends primarily on caregivers and palliative care. Clinical metrics inadequately gauge efficacy in LsPD patients. We explored if a D dopamine agonist would have efficacy in LsPD using a double-blind placebo-controlled crossover phase Ia/b study comparing the D agonist PF-06412562 to levodopa/carbidopa in six LsPD patients. Caregiver assessment was the primary efficacy measure because caregivers were with patients throughout the study, and standard clinical metrics inadequately gauge efficacy in LsPD. Assessments included standard quantitative scales of motor function (MDS-UPDRS-III), alertness (Glasgow Coma and Stanford Sleepiness Scales), and cognition (Severe Impairment and Frontal Assessment Batteries) at baseline (Day 1) and thrice daily during drug testing (Days 2-3). Clinicians and caregivers completed the clinical impression of change questionnaires, and caregivers participated in a qualitative exit interview. Blinded triangulation of quantitative and qualitative data was used to integrate findings. Neither traditional scales nor clinician impression of change detected consistent differences between treatments in the five participants who completed the study. Conversely, the overall caregiver data strongly favored PF-06412562 over levodopa in four of five patients. The most meaningful improvements converged on motor, alertness, and functional engagement. These data suggest for the first time that there can be useful pharmacological intervention in LsPD patients using D agonists and also that caregiver perspectives with mixed method analyses may overcome limitations using methods common in early-stage patients. The results encourage future clinical studies and understanding of the most efficacious signaling properties of a D agonist for this population.
Topics: Humans; Parkinson Disease; Levodopa; Dopamine Agonists; Antiparkinson Agents; Dopamine
PubMed: 37238699
DOI: 10.3390/biom13050829 -
Neuropsychology Review Dec 2021The usefulness of eye-tracking tasks as potential biomarkers for motor or cognitive disease burden in Parkinson's disease (PD) has been subject of debate for many years.... (Meta-Analysis)
Meta-Analysis Review
The usefulness of eye-tracking tasks as potential biomarkers for motor or cognitive disease burden in Parkinson's disease (PD) has been subject of debate for many years. Several studies suggest that the performance in the antisaccade task may be altered in patients with PD and associated with motor disease severity or executive dysfunction. In this meta-analysis, random effects models were used to synthesize the existing evidence on antisaccade error rates and latency in PD. Furthermore, meta-regressions were performed to assess the role of motor and cognitive disease severity, dopaminergic medication and methodological factors. Additionally, the impact of acute levodopa administration and activation of deep brain stimulation was evaluated in two separate sub-analyses.This meta-analysis confirms that antisaccade latency and error rate are significantly increased in PD. Disease duration, Unified Parkinson's disease rating scale score and Hoehn and Yahr stage mediate the effect of PD on antisaccade latency with higher motor burden being associated with increased antisaccade latency.Acute administration of levodopa had no significant effects on antisaccade performance in a small number of eligible studies. Deep brain stimulation in the subthalamic nucleus, on the other hand, may alter the speed accuracy trade-off supporting an increase of impulsivity following deep brain stimulation in PD.According to the results of the meta-analysis, antisaccade latency may provide a potential marker for disease severity and progression in PD which needs further confirmation in longitudinal studies.
Topics: Cognition Disorders; Deep Brain Stimulation; Humans; Levodopa; Parkinson Disease; Subthalamic Nucleus
PubMed: 33742354
DOI: 10.1007/s11065-021-09489-1 -
Ophthalmology. Retina Sep 2023To determine whether levodopa (L-DOPA) is associated with a reduced likelihood of developing neovascular age-related macular degeneration (AMD). (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To determine whether levodopa (L-DOPA) is associated with a reduced likelihood of developing neovascular age-related macular degeneration (AMD).
DESIGN
Three studies were performed: retrospective analyses in the Vestrum Health Retina Database (#1-2) and case-control analysis in the Merative MarketScan Research Databases (#3).
PARTICIPANTS
Eyes with neovascular AMD and 2 years of follow-up (#1). Eyes with non-neovascular AMD and 1 to 5 years of follow-up (#2). Patients aged ≥ 55 years with newly diagnosed neovascular AMD matched to controls without neovascular AMD (#3).
METHODS
Eyes were divided into 2 groups (#1-2): exposed to L-DOPA before or on the date of neovascular (#1) or nonneovascular (#2) AMD diagnosis, and eyes not exposed to L-DOPA. We extracted AMD risk factors, number of intravitreal injections (#1), and conversion rate to neovascular AMD (#2). We calculated the percentage of newly diagnosed neovascular AMD cases and matched controls exposed to any L-DOPA and determined the cumulative 2-year dose in grams by tertiles (< 100 mg, approximately 100-300 mg, and approximately > 300 mg per day, #3).
MAIN OUTCOME MEASURES
Number of intravitreal injections (#1) and detection of new-onset neovascular AMD (#2-3) after adjusting for AMD risk factors.
RESULTS
In the Vestrum database, eyes with neovascular AMD that were exposed to L-DOPA underwent 1 fewer intravitreal injection over 2 years (N = 84 088 control vs. 530 L-DOPA eyes, P = 0.006). In eyes with nonneovascular AMD (N = 42 081-203 155 control vs. 314-1525 L-DOPA eyes), L-DOPA exposure was associated with a reduced risk of conversion to neovascular AMD by 21% at year 2 (P = 0.029), 35% at years 3 to 4 (P < 0.001), and 28% at year 5 (P = 0.024). In the MarketScan databases (N = 86 900 per group), cumulative 2-year doses of L-DOPA between approximately 100 to 300 mg per day and approximately > 300 mg were associated with decreased odds of developing neovascular AMD by 15% (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.75-0.97) and 23% (OR, 0.77; 95% CI, 0.67-0.87), respectively.
CONCLUSIONS
Levodopa use was associated with reduced detection of new-onset neovascular AMD. A prospective, randomized clinical trial should be considered to investigate whether low-dose L-DOPA reduces neovascular AMD conversion.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Topics: Humans; Levodopa; Macular Degeneration; Retrospective Studies; Prospective Studies; Eye
PubMed: 37146684
DOI: 10.1016/j.oret.2023.04.014