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Neuroscience and Biobehavioral Reviews Jun 2024Dopamine's role in addiction has been extensively studied, revealing disruptions in its functioning throughout all addiction stages. Neuromelanin in the substantia nigra... (Meta-Analysis)
Meta-Analysis Review
Dopamine's role in addiction has been extensively studied, revealing disruptions in its functioning throughout all addiction stages. Neuromelanin in the substantia nigra (SN) may reflect dopamine auto-oxidation, and can be quantified using neuromelaninsensitive magnetic resonance imaging (neuromelanin-MRI) in a non-invasive manner.In this pre-registered systematic review, we assess the current body of evidence related to neuromelanin levels in substance use disorders, using both post-mortem and MRI examinations. The systematic search identified 10 relevant articles, primarily focusing on the substantia nigra. An early-stage meta-analysis (n = 6) revealed varied observations ranging from standardized mean differences of -3.55 to +0.62, with a pooled estimate of -0.44 (95 % CI = -1.52, 0.65), but there was insufficient power to detect differences in neuromelanin content among individuals with substance use disorders. Our gap analysis highlights the lack of sufficient replication studies, with existing studies lacking the power to detect a true difference, and a complete lack of neuromelanin studies on certain substances of clinical interest. We provide recommendations for future studies of dopaminergic neurobiology in addictions and related psychiatric comorbidities.
Topics: Humans; Melanins; Substance-Related Disorders; Substantia Nigra; Magnetic Resonance Imaging
PubMed: 38678736
DOI: 10.1016/j.neubiorev.2024.105690 -
The European Journal of Neuroscience Mar 2024Dopamine, a catecholamine neurotransmitter, has historically been associated with the encoding of reward, whereas its role in aversion has received less attention. Here,...
Dopamine, a catecholamine neurotransmitter, has historically been associated with the encoding of reward, whereas its role in aversion has received less attention. Here, we systematically gathered the vast evidence of the role of dopamine in the simplest forms of aversive learning: classical fear conditioning and extinction. In the past, crude methods were used to augment or inhibit dopamine to study its relationship with fear conditioning and extinction. More advanced techniques such as conditional genetic, chemogenic and optogenetic approaches now provide causal evidence for dopamine's role in these learning processes. Dopamine neurons encode conditioned stimuli during fear conditioning and extinction and convey the signal via activation of D receptor sites particularly in the amygdala, prefrontal cortex and striatum. The coordinated activation of dopamine receptors allows for the continuous formation, consolidation, retrieval and updating of fear and extinction memory in a dynamic and reciprocal manner. Based on the reviewed literature, we conclude that dopamine is crucial for the encoding of classical fear conditioning and extinction and contributes in a way that is comparable to its role in encoding reward.
Topics: Dopamine; Extinction, Psychological; Conditioning, Classical; Fear; Prefrontal Cortex; Avoidance Learning
PubMed: 37848184
DOI: 10.1111/ejn.16157 -
Journal of the ASEAN Federation of... 2024There has been an increasing awareness of the effects of combining bromocriptine-QR with other medications for diabetes mellitus type 2. This study aimed to assess the... (Meta-Analysis)
Meta-Analysis Review
Efficacy and Safety of Bromocriptine-QR as an Adjunctive Therapy on Glycemic Control in Subjects with Uncontrolled Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis.
INTRODUCTION
There has been an increasing awareness of the effects of combining bromocriptine-QR with other medications for diabetes mellitus type 2. This study aimed to assess the efficacy and safety of bromocriptine-QR as an adjunctive therapy for patients with uncontrolled type 2 diabetes mellitus.
METHODOLOGY
This systematic review is registered at the International Prospective Register of Systematic Reviews (CRD42022360326). Literature search was done via MEDLINE, NCBI, Google Scholar, Science Direct, Europe PMC and Cochrane Library databases. We included randomized controlled trials with participants 18 years old and above with uncontrolled type 2 diabetes mellitus. The primary outcome of interest is the efficacy and safety of bromocriptine-QR as an adjunctive therapy for glycemic control. Case reports, case series, reviews and animal studies were excluded. The risk of bias was reviewed using the Cochrane Risk of Bias tool. Meta-analysis was performed using Review Manager 5.4 and presented as a weighted mean difference and 95% confidence interval for changes from the baseline level.
RESULTS
Nine studies were included in the systematic review with a total of 2709 participants. The baseline HbA1c in the bromocriptine-QR group was 7.42% and 7.51% in the control group. The bromocriptine-QR group was favoured, outperforming the control group in terms of reducing hemoglobin A1c(HbA1c), with a statistically significant difference (weighted mean difference -0.6%; 95% CI [-0.83,-0.36]; p<0.00001). The most common side effects were nausea (33.75% vs 6.92%), fatigue (13.11% vs 5.94%), and headache (11.17% vs 6.87%).
CONCLUSION
Administration of bromocriptine-QR at a dose range of 1.6 to 4.8 mg/day as an adjunctive therapy reduced HbA1c and FBG in patients with uncontrolled type 2 diabetes mellitus (T2DM). However, there were also statistically greater odds of the occurrence of adverse events such as nausea, vomiting, and headache compared to controls.
Topics: Humans; Diabetes Mellitus, Type 2; Bromocriptine; Glycemic Control; Hypoglycemic Agents; Blood Glucose; Glycated Hemoglobin; Treatment Outcome; Drug Therapy, Combination; Dopamine Agonists
PubMed: 38863918
DOI: 10.15605/jafes.039.01.19 -
Biomedicines Feb 2024In light of the unsuccessful traditional therapies for Parkinson's disease (PD) overmany years, there is an unmet need for the development of novel therapies to... (Review)
Review
In light of the unsuccessful traditional therapies for Parkinson's disease (PD) overmany years, there is an unmet need for the development of novel therapies to alleviate the symptoms of PD retardation or halt the progression of the disease itself. This systematic review aims to critically update some of the most promising novel treatments including gene therapy, cell-based therapies, targeted drug delivery, and neuroprotective agents, focusing on their challenges, limitations and future directions in PD research. Gene therapy in PD is encouraging, with AAV-based approaches targeting neurotrophic factors, dopamine production, and neuronal circuits in animal and clinical trials. A promising approach to targeted drug delivery for PD involves the use of nanotechnology to create drug delivery vehicles that can traverse the blood-brain barrier and deliver medications specifically to the regions of the brain affected by PD. Neuroprotective agents are compounds that have the ability to protect neurons from degeneration and death, and they hold great promise for the evolution of disease-modifying treatments for PD. Magnetic field therapy is a promising non-invasive method that promotes neural plasticity in PD. The establishment of standardized protocols for animal and human studies, safety, ethical considerations, and cost-effectiveness are the major challenges for the future research of novel PD therapies. The development of novel therapies for PD represents a promising path toward to effective personalized disease-modifying treatments for PD.
PubMed: 38540162
DOI: 10.3390/biomedicines12030549 -
Menopause (New York, N.Y.) Feb 2024Prolactinomas occurring during the reproductive period exhibit a characteristic behavior. There are, however, gaps in the literature regarding the behavior of these...
IMPORTANCE
Prolactinomas occurring during the reproductive period exhibit a characteristic behavior. There are, however, gaps in the literature regarding the behavior of these tumors after menopause.
OBJECTIVE
This study aimed to review and characterize the influence of menopause on prolactinoma behavior.
EVIDENCE REVIEW
A systematic review of observational prospective or retrospective studies and clinical trials on prolactinomas was conducted in two situations: tumors diagnosed in the reproductive period (before menopause), with follow-up in the postmenopausal period, or prolactinomas diagnosed in the postmenopausal period, without language or date restrictions. Data extracted from the articles included patient and tumor characteristics (prolactinoma type, previous treatment, symptoms, and serum prolactin [PRL] levels).
FINDINGS
This study included five studies comprising 180 participants. Prolactinomas diagnosed in women of reproductive age are treated with dopaminergic agonists (DAs), with indications of treatment withdrawal after menopause, exhibited stable tumor behavior and PRL levels. Considering the diagnosis during the postmenopausal period, macroprolactinomas were more prevalent and showed tumor shrinkage when DAs were used. Cabergoline, the most commonly used drug, lowers PRL levels and reduces symptoms associated with adenoma.
CONCLUSIONS AND RELEVANCE
Microadenomas diagnosed before menopause can be followed up without treatment. Prolactinomas diagnosed after menopause are typically macroadenomas. Cabergoline remains the treatment of choice in the presence of clinical or compressive symptoms. We recommend at least one annual follow-up for such patients.
Topics: Humans; Female; Prolactinoma; Cabergoline; Postmenopause; Pituitary Neoplasms; Dopamine Agonists; Retrospective Studies; Prospective Studies; Prolactin
PubMed: 38194617
DOI: 10.1097/GME.0000000000002303 -
Cureus Jul 2023Diabetes mellitus (DM), one of the oldest diseases known to mankind has always been difficult to treat even with the availability of a variety of medications. In such a... (Review)
Review
Diabetes mellitus (DM), one of the oldest diseases known to mankind has always been difficult to treat even with the availability of a variety of medications. In such a scenario, the Food and Drug Administration (FDA) has approved a novel therapeutic, bromocriptine, with a different mechanism of action than the traditional medications since 2009 but has not been used as either first-line therapy or add-on therapy. In this systematic review, we searched databases like PubMed, Medline, PubMed Central, Cochrane Library, Clinicaltrials.gov, and Wiley Online Library. The selected articles were screened using inclusion and exclusion criteria and quality appraised; finally, 11 studies including eight clinical trials and three narrative reviews were included. It was found that an increase in dopamine and serotonin levels were hypothesized to convert the insulin-resistant (IR) state to an insulin-sensitive (IS) state. Hence in DM, as there is an IR state, the administration of dopamine was hypothesized to increase insulin sensitivity. In our study based on included studies, it was found that bromocriptine was superior as an add-on therapy to metformin compared to metformin alone, also it was found beneficial in people failing treatment with any one oral hypoglycemic agent. On the contrary, bromocriptine was found inferior to teneligliptin in treating DM. Still, more studies are required to make an accurate and reliable assessment of the efficacy of bromocriptine in treating DM.
PubMed: 37588318
DOI: 10.7759/cureus.41931 -
Psychiatry Research. Neuroimaging Apr 2024Dopamine and norepinephrine are implicated in the pathophysiology of mental disorders, but non-invasive study of their neuronal function remains challenging. Recent... (Review)
Review
Dopamine and norepinephrine are implicated in the pathophysiology of mental disorders, but non-invasive study of their neuronal function remains challenging. Recent research suggests that neuromelanin-sensitive magnetic resonance imaging (NM-MRI) techniques may overcome this limitation by enabling the non-invasive imaging of the substantia nigra (SN)/ ventral tegmental area (VTA) dopaminergic and locus coeruleus (LC) noradrenergic systems. A review of 19 studies that met the criteria for NM-MRI application in mental disorders found that despite the use of heterogeneous sequence parameters and metrics, nearly all studies reported differences in contrast ratio (CNR) of LC or SN/VTA between patients with mental disorders and healthy controls. These findings suggest that NM-MRI is a valuable tool in psychiatry, but the differences in sequence parameters across studies hinder comparability, and a standardized analysis pipeline is needed to improve the reliability of results. Further research using standardized methods is needed to better understand the role of dopamine and norepinephrine in mental disorders.
Topics: Humans; Dopamine; Reproducibility of Results; Magnetic Resonance Imaging; Mental Disorders; Norepinephrine; Melanins
PubMed: 38325165
DOI: 10.1016/j.pscychresns.2024.111785 -
Pituitary Jun 2024Prolactinomas are common tumours that significantly reduce quality-of-life (QOL) due to sellar mass effect, secondary hypogonadism, and the peripheral effects of...
BACKGROUND
Prolactinomas are common tumours that significantly reduce quality-of-life (QOL) due to sellar mass effect, secondary hypogonadism, and the peripheral effects of prolactin. Understanding the factors that influence QOL would provide insights into therapeutic targets to optimise patient outcomes and improve wellbeing in prolactinoma.
METHODS
A systematic review was performed in accordance with the PRISMA statement. Studies that reported patient QoL using validated metrics were included. Bias and methodological rigour were assessed using the MINORS criteria.
RESULTS
A total of 18 studies were identified studies were available for review, comprising 877 patients. Most were small cross-sectional studies at high risk of bias. Prolactinoma exhibit worse QOL than healthy controls, particularly mental and psychosocial wellbeing. QOL is also worse than patients with non-functional adenomas, but better than those with Cushing's disease and acromegaly. QOL correlates with prolactin levels, and approaches population baseline with prolonged biochemical control. Dopamine agonists and surgery both improve overall QOL, however improvements are more rapid with surgery.
CONCLUSION
Poor quality of life in prolactinoma is multifactorial, related to biochemical control, side effects of therapy, and sellar mass effect. Targeting persistent symptoms, reducing healthcare costs, and reducing side-effects of therapy are avenues to improving QOL in patients with prolactinoma.
Topics: Prolactinoma; Humans; Quality of Life; Pituitary Neoplasms; Dopamine Agonists
PubMed: 38656635
DOI: 10.1007/s11102-024-01392-1 -
Nutrition Research (New York, N.Y.) Jan 2024Parkinson disease (PD) is characterized by the loss of dopaminergic neurons because of oxidative stress and neuroinflammation. Polyphenols in vegetables, known for their...
Parkinson disease (PD) is characterized by the loss of dopaminergic neurons because of oxidative stress and neuroinflammation. Polyphenols in vegetables, known for their high antioxidant capacity, may prevent the onset, or delay the progression of the disease; among these, flavonoids are the most abundant class of polyphenols in foods. Clinical and cohort studies have evaluated the effect of polyphenol consumption on the risk of developing PD or of attenuating the symptoms after diagnosis; therefore, it is necessary to integrate the scientific evidence into making dietary recommendations. The objective of this study was to perform a systematic review of randomized controlled trials and cohort studies that have investigated the use of polyphenols in PD. The studies were identified through the PubMed, Science Direct, Scielo, and Web of Science databases. A total of 1100 studies were found; these were analyzed and filtered by 2 independent reviewers. After completion, 5 studies were included (3 randomized controlled trials and 2 cohort studies). The consumption of flavonoids, anthocyanins, or 2-5 servings/week of specific foods (apples, red wine, blueberries, and strawberries) reduces the risk of PD and associated mortality. Treatment with licorice, curcumin, or cocoa, which are rich in flavonoids and other polyphenols, improves motor function in PD patients. No statistically significant differences were found in quality of life, disease progression or nonmotor symptoms such as cognitive ability and mood. Although cohort studies suggest a neuroprotective effect, further clinical studies are urgently needed to evaluate the effect of specific flavonoids and other polyphenols in PD.
Topics: Humans; Anthocyanins; Flavonoids; Parkinson Disease; Polyphenols; Quality of Life
PubMed: 38039600
DOI: 10.1016/j.nutres.2023.10.004 -
BMJ Paediatrics Open May 2024There exists limited agreement on the recommendations for the treatment of transitional circulatory instability (TCI) in preterm neonates OBJECTIVE: To compare the... (Meta-Analysis)
Meta-Analysis Comparative Study
Comparative efficacy of volume expansion, inotropes and vasopressors in preterm neonates with probable transitional circulatory instability in the first week of life: a systematic review and network meta-analysis.
BACKGROUND
There exists limited agreement on the recommendations for the treatment of transitional circulatory instability (TCI) in preterm neonates OBJECTIVE: To compare the efficacy of various interventions used to treat TCI METHODS: Medline and Embase were searched from inception to 21 July 2023. Two authors extracted the data independently. A Bayesian random effects network meta-analysis was used. Recommendations were formulated using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework.
INTERVENTIONS
Dopamine, dobutamine, epinephrine, hydrocortisone, vasopressin, milrinone, volume and placebo.
MAIN OUTCOME MEASURES
Mortality, major brain injury (MBI) (intraventricular haemorrhage > grade 2 or cystic periventricular leukomalacia), necrotising enterocolitis (NEC) ≥stage 2 and treatment response (as defined by the author).
RESULTS
15 Randomized Controlled Trials (RCTs) were included from the 1365 titles and abstracts screened. Clinical benefit or harm could not be ruled out for the critical outcome of mortality. For the outcome of MBI, epinephrine possibly decreased the risk when compared to dobutamine and milrinone (very low certainty). Epinephrine was possibly associated with a lesser risk of NEC when compared with dopamine, dobutamine, hydrocortisone and milrinone (very low certainty). Dopamine was possibly associated with a lesser risk of NEC when compared with dobutamine (very low certainty). Vasopressin possibly decreased the risk of NEC compared with dopamine, dobutamine, hydrocortisone and milrinone (very low certainty). Clinical benefit or harm could not be ruled out for the outcome response to treatment.
CONCLUSIONS
Epinephrine may be used as the first-line drug in preterm neonates with TCI, the evidence certainty being very low. We suggest future trials evaluating the management of TCI with an emphasis on objective criteria to define it.
Topics: Humans; Infant, Newborn; Cardiotonic Agents; Vasoconstrictor Agents; Infant, Premature; Network Meta-Analysis; Infant, Premature, Diseases; Randomized Controlled Trials as Topic; Dobutamine
PubMed: 38769048
DOI: 10.1136/bmjpo-2024-002500