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Neuroendocrinology 2022Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of... (Review)
Review
Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of cabergoline-treated individuals exhibit resistance to DAs. In addition, the mechanism underlying this phenomenon remains elusive. In this study, we summarize the major findings regarding the role of microRNAs (miRNAs) in the pathogenesis of DA-resistant prolactinoma (DARP). Currently available evidence suggests that miRNAs are usually dysregulated in DARP and that, although controversial, the dysregulated miRNAs target the transforming growth factor (TGF)-β, dopamine 2 receptor (D2R), or estradiol (E2)/estrogen receptor (ER) signaling pathways to mediate the therapeutic effect of DAs. These findings provide new incentives for research on innovative strategies for predicting patients' responsiveness to dopamine therapies and for developing treatment approaches. Unfortunately, recent studies tended to focus exclusively on the differential miRNA expression profiles between DARP and dopamine-sensitive prolactinoma, and no definitive consensus has been reached regarding the role of these miRNAs in the modulation mechanism. Therefore, current and future efforts should be directed toward the exploration of the mechanism underlying the dysregulation of miRNAs as well as of the target proteins that are affected by the dysregulated miRNAs. Furthermore, the modulation of the expression of dysregulated miRNAs, which target the D2R, TGF-β, or E2/ER signaling pathways, might be a promising alternative to treat patients with DARP and improve their prognosis.
Topics: Dopamine; Dopamine Agonists; Drug Resistance, Neoplasm; Humans; MicroRNAs; Pituitary Neoplasms; Prolactinoma
PubMed: 34034260
DOI: 10.1159/000517356 -
Cell Reports. Medicine Oct 2023Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat...
Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat Parkinson's disease (L-DOPA-induced dyskinesia [LID]) or dopamine antagonists to treat schizophrenia (tardive dyskinesia [TD]). However, it remains unknown why distinct types of medications for distinct neuropsychiatric disorders induce similar involuntary movements. Here, we search for a shared structural footprint using magnetic resonance imaging-based macroscopic screening and super-resolution microscopy-based microscopic identification. We identify the enlarged axon terminals of striatal medium spiny neurons in LID and TD model mice. Striatal overexpression of the vesicular gamma-aminobutyric acid transporter (VGAT) is necessary and sufficient for modeling these structural changes; VGAT levels gate the functional and behavioral alterations in dyskinesia models. Our findings indicate that lowered type 2 dopamine receptor signaling with repetitive dopamine fluctuations is a common cause of VGAT overexpression and late-onset dyskinesia formation and that reducing dopamine fluctuation rescues dyskinesia pathology via VGAT downregulation.
Topics: Mice; Animals; Dopamine Agonists; Levodopa; Dopamine; Antiparkinson Agents; Parkinsonian Disorders; Dyskinesia, Drug-Induced; Oxidopamine; gamma-Aminobutyric Acid
PubMed: 37774703
DOI: 10.1016/j.xcrm.2023.101208 -
Medicine Dec 2022Restless leg syndrome (Restless legs syndrome, RLS) is a common neurological disorder. The pathogenesis of RLS remains unknown, and recent pathophysiological... (Review)
Review
Restless leg syndrome (Restless legs syndrome, RLS) is a common neurological disorder. The pathogenesis of RLS remains unknown, and recent pathophysiological developments have shown the contribution of various genetic markers, neurotransmitter dysfunction, and iron deficiency to the disease, as well as other unidentified contributing mechanisms, particularly chronic renal dysfunction. RLS enhancement syndrome is frequently observed in patients with RLS who have received long-term dopamine agonist therapy, manifesting as a worsening of RLS symptoms, usually associated with an increase in the dose of dopamine agonist. Some patients with RLS can adequately control their symptoms with non-pharmacological measures such as massage and warm baths. First-line treatment options include iron supplementation for those with evidence of reduced iron stores, or gabapentin or pregabalin, as well as dopamine agonists, such as pramipexole. Second-line therapies include opioids such as tramadol. RLS seriously affects the quality of life of patients, and because its pathogenesis is unclear, more biological evidence and treatment methods need to be explored.
Topics: Humans; Dopamine Agonists; Restless Legs Syndrome; Quality of Life; Gabapentin; Iron
PubMed: 36550837
DOI: 10.1097/MD.0000000000032324 -
Neuroendocrinology 2019Dopamine agonists are usually very effective in the treatment of prolactinomas. Nonetheless, a subset of individuals does not respond satisfactorily to these agents, and... (Review)
Review
Dopamine agonists are usually very effective in the treatment of prolactinomas. Nonetheless, a subset of individuals does not respond satisfactorily to these agents, and this resistance is characterized by failure to achieve normoprolactinemia and a 30% or more reduction in maximal tumor diameter (in the case of macroprolactinoma) under maximally tolerated doses. The overall prevalence of dopamine agonist resistance is 20-30% for bromocriptine (BRC) and around 10% for cabergoline (CAB). The 2 main predictive factors are male gender and tumor invasiveness. The management of drug-resistant prolactinomas includes several options. Any BRC-resistant patient should be switched to CAB which will normalize prolactin in 80% of patients. As long as adverse effects do not develop, dose escalation of CAB is reasonable, with the expectation that subsequent dose reduction will be possible. Echocardiographic monitoring is advised in such patients because of the potential association with cardiac valvular fibrosis. Also, maintaining maximal CAB doses at 3.5 mg/week may lead to progressive hormonal control in a significant proportion of patients. Complete resistance to CAB is infrequent. In a study of 122 patients with a macroprolactinoma, only 7 (6%) could not achieve control despite maximal CAB doses for > 12 months. A large resistant prolactinoma is also an indication for transsphenoidal neurosurgery, aiming at a debulking which may improve postoperative medical control. For patients who harbor aggressive prolactinomas, radiotherapy may be considered. However, normal prolactinemia will eventually occur in only one-third of patients after many years. Finally, temozolomide may be a therapeutic option in malignant/aggressive prolactinomas.
Topics: Bromocriptine; Cabergoline; Dopamine Agonists; Drug Resistance; Humans; Pituitary Neoplasms; Prolactinoma
PubMed: 30481756
DOI: 10.1159/000495775 -
Anatolian Journal of Cardiology Jan 2019
Topics: Dopamine Agonists; Heart Failure; Humans
PubMed: 30587711
DOI: No ID Found -
Neuroendocrinology 2016Pierre Marie coined the term 'acromegaly' in 1886 and linked it to a distinct clinical disease with a characteristic clinical picture. However, Pierre Marie was not the... (Review)
Review
Pierre Marie coined the term 'acromegaly' in 1886 and linked it to a distinct clinical disease with a characteristic clinical picture. However, Pierre Marie was not the first physician to give a full record of the clinical picture of acromegaly; others had preceded him, like the Dutch physician Johannes Wier. After Marie, pituitary enlargement was noted in almost all patients with acromegaly. Subsequently it was discovered that pituitary hyperfunction caused by a pituitary tumour was indeed the cause of acromegaly. The cause of acromegaly could be further determined after the discovery of growth hormone (GH) and insulin-like growth factor I (IGF-I) and after demonstrating an association with GH hypersecretion and elevated circulating IGF-I. From the beginning of the 20th century, acromegaly could be treated by pituitary surgery and/or radiotherapy. After 1970, medical therapies were introduced that could control acromegaly. First, dopamine agonists were introduced, followed by somatostatin analogues and GH receptor blockers.
Topics: Acromegaly; Dopamine Agonists; Human Growth Hormone; Humans; Pituitary Gland; Pituitary Neoplasms; Somatostatin
PubMed: 25572320
DOI: 10.1159/000371808 -
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 -
Sleep Medicine May 2016A Task Force was established by the International Restless Legs Syndrome Study Group (IRLSSG) in conjunction with the European Restless Legs Syndrome Study Group...
Guidelines for the first-line treatment of restless legs syndrome/Willis-Ekbom disease, prevention and treatment of dopaminergic augmentation: a combined task force of the IRLSSG, EURLSSG, and the RLS-foundation.
A Task Force was established by the International Restless Legs Syndrome Study Group (IRLSSG) in conjunction with the European Restless Legs Syndrome Study Group (EURLSSG) and the RLS Foundation (RLS-F) to develop evidence-based and consensus-based recommendations for the prevention and treatment of long-term pharmacologic treatment of dopaminergic-induced augmentation in restless legs syndrome/Willis-Ekbom disease (RLS/WED). The Task Force made the following prevention and treatment recommendations: As a means to prevent augmentation, medications such as α2δ ligands may be considered for initial RLS/WED treatment; these drugs are effective and have little risk of augmentation. Alternatively, if dopaminergic drugs are elected as initial treatment, then the daily dose should be as low as possible and not exceed that recommended for RLS/WED treatment. However, the physician should be aware that even low dose dopaminergics can cause augmentation. Patients with low iron stores should be given appropriate iron supplementation. Daily treatment by either medication should start only when symptoms have a significant impact on quality of life in terms of frequency and severity; intermittent treatment might be considered in intermediate cases. Treatment of existing augmentation should be initiated, where possible, with the elimination/correction of extrinsic exacerbating factors (iron levels, antidepressants, antihistamines, etc.). In cases of mild augmentation, dopamine agonist therapy can be continued by dividing or advancing the dose, or increasing the dose if there are breakthrough night-time symptoms. Alternatively, the patient can be switched to an α2δ ligand or rotigotine. For severe augmentation the patient can be switched either to an α2δ ligand or rotigotine, noting that rotigotine may also produce augmentation at higher doses with long-term use. In more severe cases of augmentation an opioid may be considered, bypassing α2δ ligands and rotigotine.
Topics: Consensus; Dopamine Agonists; Drug Synergism; Evidence-Based Medicine; Humans; Practice Guidelines as Topic; Restless Legs Syndrome
PubMed: 27448465
DOI: 10.1016/j.sleep.2016.01.017 -
Neuroendocrinology 2019The discovery of dopamine inhibitory effects on prolactin secretion has led to an era of successful dopaminergic therapy for prolactinomas. Herein we provide an overview... (Review)
Review
The discovery of dopamine inhibitory effects on prolactin secretion has led to an era of successful dopaminergic therapy for prolactinomas. Herein we provide an overview of the evolution of dopamine agonists and their use in patients with PRL-secreting pituitary tumors, starting from the 1970s up to today, highlighting that normalization of PRL levels, restoration of eugonadism, and reduction of tumor mass can be achieved in the majority of patients by treatment with dopamine agonists.
Topics: Dopamine Agonists; Humans; Pituitary Neoplasms; Prolactinoma
PubMed: 30852578
DOI: 10.1159/000499470 -
Dopamine Agonist Cotreatment Alters Neuroplasticity and Pharmacology of Levodopa-Induced Dyskinesia.Movement Disorders : Official Journal... Mar 2023Current models of levodopa (L-dopa)-induced dyskinesia (LID) are obtained by treating dopamine-depleted animals with L-dopa. However, patients with LID receive...
BACKGROUND
Current models of levodopa (L-dopa)-induced dyskinesia (LID) are obtained by treating dopamine-depleted animals with L-dopa. However, patients with LID receive combination therapies that often include dopamine agonists.
OBJECTIVE
Using 6-hydroxydopamine-lesioned rats as a model, we aimed to establish whether an adjunct treatment with the D2/3 agonist ropinirole impacts on patterns of LID-related neuroplasticity and drug responses.
METHODS
Different regimens of L-dopa monotreatment and L-dopa-ropinirole cotreatment were compared using measures of hypokinesia and dyskinesia. Striatal expression of ∆FosB and angiogenesis markers were studied immunohistochemically. Antidyskinetic effects of different drug categories were investigated in parallel groups of rats receiving either L-dopa monotreatment or L-dopa combined with ropinirole.
RESULTS
We defined chronic regimens of L-dopa monotreatment and L-dopa-ropinirole cotreatment inducing overall similar abnormal involuntary movement scores. Compared with the monotreatment group, animals receiving the L-dopa-ropinirole combination exhibited an overall lower striatal expression of ∆FosB with a distinctive compartmental distribution. The expression of angiogenesis markers and blood-brain barrier hyperpermeability was markedly reduced after L-dopa-ropinirole cotreatment compared with L-dopa monotreatment. Moreover, significant group differences were detected upon examining the response to candidate antidyskinetic drugs. In particular, compounds modulating D1 receptor signaling had a stronger effect in the L-dopa-only group, whereas both amantadine and the selective NMDA antagonist MK801 produced a markedly larger antidyskinetic effect in L-dopa-ropinirole cotreated animals.
CONCLUSIONS
Cotreatment with ropinirole altered LID-related neuroplasticity and pharmacological response profiles. The impact of adjuvant dopamine agonist treatment should be taken into consideration when investigating LID mechanisms and candidate interventions in both clinical and experimental settings. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Topics: Rats; Animals; Levodopa; Dopamine Agonists; Antiparkinson Agents; Rats, Sprague-Dawley; Dyskinesia, Drug-Induced; Oxidopamine; Disease Models, Animal
PubMed: 36656044
DOI: 10.1002/mds.29301