An Investigation on the Clinical Features and Neurochemical Changes in Parkinson's Disease With Depression

Behind the Mask: Parkinson's Disease and Depression

Parkinson's disease (PD) is a common, prevalent neurodegenerative disease. It is mainly characterized by motor symptoms such as rigidity, tremors, and bradykinesia, but it can also manifest with non-motor symptoms, of which depression is the most frequent. The latter can impair the quality of life, yet it gets overlooked and goes untreated because of the significant overlap in their clinical features, hence making the diagnosis difficult. Furthermore, there is limited data on the availability of appropriate criteria for making the diagnosis of depression in PD patients, as it can occur with varying expressions throughout the course of PD or it can also precede it. This review article has included a brief discussion on the diagnosis of depression in PD patients and their overlapped clinical manifestations. Understanding the mechanisms underlying the disease processes of PD and depression and the pathways interconnecting them gives better knowledge on devising treatment options for the patients. Only studies from Pubmed were included and all other databases were excluded. Studies from the last 50 years were included. Suitable references included in these studies were also extracted. Thus, depression in PD and PD in depression, along with their pharmacological and non-pharmacological treatment options, have been discussed.

Premature drug reduction after subthalamic nucleus deep brain stimulation leading to worse depression in patients with Parkinson's disease

Background

Reduction of medication in Parkinson's disease (PD) following subthalamic nucleus deep brain stimulation (STN-DBS) has been recognized, but the optimal timing for medication adjustments remains unclear, posing challenges in postoperative patient management.

Objective

This study aimed to provide evidence for the timing of medication reduction post-DBS using propensity score matching (PSM).

Methods

In this study, initial programming and observation sessions were conducted over 1 week for patients 4-6 weeks postoperatively. Patients were subsequently categorized into medication reduction or non-reduction groups based on their dyskinesia evaluation using the 4.2-item score from the MDS-UPDRS-IV. PSM was employed to maintain baseline comparability. Short-term motor and neuropsychiatric symptom assessments for both groups were conducted 3-6 months postoperatively.

Results

A total of 123 PD patients were included. Baseline balance in motor and non-motor scores was achieved between the two groups based on PSM. Short-term efficacy revealed a significant reduction in depression scores within the non-reduction group compared to baseline (P < 0.001) and a significant reduction compared to the reduction group (P = 0.037). No significant differences were observed in UPDRS-III and HAMA scores between the two groups. Within-group analysis showed improvements in motor symptoms, depression, anxiety, and subdomains in the non-reduction group, while the reduction group exhibited improvements only in motor symptoms.

Conclusion

This study provides evidence for the timing of medication reduction following DBS. Our findings suggest that early maintenance of medication stability is more favorable for improving neuropsychiatric symptoms.

Reduced homovanillic acid, SDF-1α and SCGF-β levels in cerebrospinal fluid are related to depressive states in systemic lupus erythematosus

OBJECTIVE

This study aimed to seek a new method of evaluation and surrogate markers for diffuse neuropsychiatric SLE (NPSLE).

METHODS

We enrolled 44 patients with SLE between 2017 and 2020 who fulfilled at least one of three specific inclusion criteria: high disease activity, abnormal findings (cerebrospinal fluid [CSF] examination, brain MRI, or electroencephalography), or history of neuropsychiatric illness. Psychiatric symptom rating scales (PSYRATS) were evaluated retrospectively. The primary end point was the PSYRATS positivity rate in SLE patients who had not been diagnosed with diffuse NPSLE.

RESULTS

Based on the 1999 ACR classifications, 7 out of the 44 patients evaluated using PSYRATS had been diagnosed with diffuse NPSLE. PSYRATS positivity was seen in 13 out of 37 SLE patients (35.1%) who had not been diagnosed with diffuse NPSLE, and all these patients were positive for Montgomery-Åsberg Depression Rating Scale (MADRS), an indicator of depression state in PSYRATS. Additionally, in the 20 SLE patients exhibiting depression symptoms who were MADRS-positive, CSF concentrations of the neuroinflammatory markers homovanillic acid (HVA; P = 0.0400), stromal cell-derived factor-1α (SDF-1α; P = 0.0431) and stem cell growth factor-β (SCGF-1β; P = 0.0061) were significantly reduced compared with the 24 MADRS-negative SLE patients, and the levels of HVA, SDF-1α and SCGF-1β correlated with one another (P < 0.05).

CONCLUSION

Many patients with active SLE have subclinical depression, and MADRS evaluation of neuropsychiatric symptoms is useful for detecting them. Additionally, the decrease in CSF levels of HVA, SDF-1 α and SCGF-1β reflects the same pathology, and these may serve as surrogate markers.

The pharmacological actions of Danzhi-xiaoyao-San on depression involve lysophosphatidic acid and microbiota-gut-brain axis: novel insights from a systems pharmacology analysis of a double-blind, randomized, placebo-controlled clinical trial

Danzhi-xiaoyao-San (DZXYS), a Traditional Chinese Medicine, plays an essential role in the clinical treatment of depression, but its mechanisms in humans remain unclear. To investigate its pharmacological effects and mechanisms as an add-on therapy for depression, we conducted a double-blind, placebo-controlled trial with depressed patients receiving selective serotonin reuptake inhibitors (SSRIs). Serum and fecal samples were collected for metabolomic and microbiome analysis using UHPLC-QTRAP-MS/MS and 16S rRNA gene sequencing technologies, respectively. Depression symptoms were assessed using the 24-item Hamilton Depression Scale. We employed network pharmacology, metabolomics, and molecular docking to identify potential targets associated with DZXYS. We also examined the correlation between gut microbes and metabolites to understand how DZXYS affects the microbiota-gut-brain axis. The results showed that DZXYS combined with SSRIs was more effective than SSRIs alone in improving depression. We identified 39 differential metabolites associated with DZXYS treatment and found seven upregulated metabolic pathways. The active ingredients quercetin and luteolin were docked to targets (AVPR2, EGFR, F2, and CDK6) associated with the enriched pathways 'pancreatic cancer' and 'phospholipase D signaling pathway', which included the metabolite lysophosphatidic acid [LPA(0:0/16:0)]. Additionally, we identified 32 differential gut microbiota species related to DZXYS treatment, with Bacteroides coprophilus and Ruminococcus gnavus showing negative correlations with specific metabolites such as L-2-aminobutyric acid and LPA(0:0/16:0). Our findings indicate that DZXYS's antidepressant mechanisms involve multiple targets, pathways, and the regulation of LPA and the microbiota-gut-brain axis. These insights from our systems pharmacology analysis contribute to a better understanding of DZXYS's potential pharmacological mechanisms in depression treatment.Communicated by Ramaswamy H. Sarma.

Mood disturbances in Parkinson's disease: From prodromal origins to application of animal models

Parkinson's disease (PD) is a complex illness with a constellation of environmental insults and genetic vulnerabilities being implicated. Strikingly, many studies only focus on the cardinal motor symptoms of the disease and fail to appreciate the major non-motor features which typically occur early in the disease process and are debilitating. Common comorbid psychiatric features, notably clinical depression, as well as anxiety and sleep disorders are thought to emerge before the onset of prominent motor deficits. In this review, we will delve into the prodromal stage of PD and how early neuropsychiatric pathology might unfold, followed by later motor disturbances. It is also of interest to discuss how animal models of PD capture the complexity of the illness, including depressive-like characteristics along with motor impairment. It remains to be determined how the underlying PD disease processes contributes to such comorbidity. But some of the environmental toxicants and microbial pathogens implicated in PD might instigate pro-inflammatory effects favoring α-synuclein accumulation and damage to brainstem neurons fueling the evolution of mood disturbances. We posit that comprehensive animal-based research approaches are needed to capture the complexity and time-dependent nature of the primary and co-morbid symptoms. This will allow for the possibility of early intervention with more novel and targeted treatments that fit with not only individual patient variability, but also with changes that occur over time with the evolution of the disease.

Neurobiology of depression in Parkinson's disease: Insights into epidemiology, molecular mechanisms and treatment strategies

Parkinson's disease (PD) is characterized mainly by motor dysfunctions due to the progressive loss of dopaminergic neurons. However, PD patients experience a multitude of debilitating non-motor symptoms, including depression, which may have deleteriously detrimental effects on life. Depression is multifactorial and exhibits a bimodal progression in PD, but its underlying molecular mechanisms are poorly understood. Studies demonstrating the pathophysiology of depression in PD and the specific treatment strategies for depression-like symptoms in PD patients are largely lacking, often underrated, under-recognized and, consequently, inadequately/under-treated. Nevertheless, reports suggest that the incidence of depression is approximately 20-30% of PD patients and may precede the onset of motor symptoms. Diagnosing depression in PD becomes difficult due to the clinical overlap in symptomatology between the two diseases, and the nigrostriatal dysfunction alone is insufficient to explain depressive symptoms in PD. Therefore, the current study provides an overview of the molecular mechanisms underlying the development of depression in PD and new insights into developing current antidepressant strategies to treat depression in PD. This review will identify and understand the molecular pathological mechanisms of depression in PD that will fundamentally help tailoring therapeutic interventions for depressive symptoms in PD.

Fenofibrate promotes neuroprotection in a model of rotenone-induced Parkinson's disease

Parkinson's disease is a neurodegenerative disease, the etiology of which remains unknown, but some likely causes include oxidative stress, mitochondrial dysfunction and neuroinflammation. Peroxisome-proliferator-activated receptor (PPAR) agonists have been studied in animal models of Parkinson's disease and have shown neuroprotective effects. In this study, we aimed to (1) confirm the neuroprotective effects of PPAR-alpha agonist fenofibrate. To this end, male rats received fenofibrate (100 mg/kg) orally for 15 days, 5 days before the intraperitoneal injections of rotenone (2.5 mg/kg for 10 days). After finishing the treatment with rotenone and fenofibrate, animals were subjected to the open field, the forced swim test and the two-way active avoidance task. Subsequently, rats were euthanized for measurement of dopamine and metabolites levels in the striatum and quantification of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra pars compacta (SNpc). In addition, we aimed to (2) evaluate the neuroprotective effects of fenofibrate on the accumulation of α-synuclein aggregates. Here, rats were treated for 5 days with fenofibrate continuing for over 28 days with rotenone. Then, animals were perfused for immunohistochemistry analysis of α-synuclein. The results showed that fenofibrate reduced depressive-like behavior and memory impairment induced by rotenone. Moreover, fenofibrate diminished the depletion of striatal dopamine and protected against dopaminergic neuronal death in the SNpc. Likewise, the administration of fenofibrate attenuated the aggregation of α-synuclein in the SNpc and striatum in the rotenone-lesioned rats. Our study confirmed that fenofibrate exerted neuroprotective effects because parkinsonian rats exhibited reduced behavioral, neurochemical and immunohistochemical changes, and importantly, a lower number of α-synuclein aggregates.

Effects of Subthalamic Nucleus Deep Brain Stimulation on Depression in Patients with Parkinson's Disease

Objective: In this study, we aimed to investigate the effects of STN-DBS on PD patients with different levels of depression and to identify predictors of the effects of STN-DBS on PD depression. Methods: We retrospectively collected data for 118 patients with PD depression who underwent STN-DBS at Beijing Tiantan Hospital. Neuropsychological, motor, and quality of life assessments were applied preoperatively and postoperatively. All patients were divided into two groups according to their HAM-D24 total scores (group I: mild depression; group Ⅱ: moderate depression). A mixed repeated-measure analysis of variance (ANOVA) was performed to investigate whether there were differences in depression scores before and after STN-DBS between the two groups. The changes in depression scores were also compared between groups using ANCOVA, adjusting for gender and preoperative HAMA scores. Logistic regression was performed to identify predictors of STN-DBS’s effects on PD depression. Results: Both groups showed significant improvement in depression symptoms after STN-DBS. Compared with patients in group I, patients in group Ⅱ showed greater reductions in their HAM-D24 total scores (p = 0.002) and in HAM-D24 subitems including cognitive disturbances (p = 0.026) and hopelessness symptoms (p = 0.018). Logistic regression indicated that gender (female) (p = 0.014) and preoperative moderate depression (p < 0.001) patients had greater improvements in depression after STN-DBS. Conclusions: Patients with moderate depression showed better improvement than patients with mild depression. Gender (female) and preoperative HAMA scores are predictors of STN-DBS’s effects on PD depression.

Naturalistic Study of Depression Associated with Parkinson’s Disease in a National Public Neurological Referral Center in Mexico

Major depressive disorder (MDD) is a major health problem in Parkinson’s disease (PD) patients. We described the clinical and sociodemographic factors of MDD among patients with PD at a national neurological referral center in Mexico. One hundred patients with PD + MDD were included in the study. All the patients were evaluated during the “ON” treatment phase of PD. Clinical scales for cognition (MMSE and MoCA) and MDD (MADRS) were applied. The mean age was 58.49 ± 11.02 years, and 57% of the sample was male. The most frequent symptom of PD was tremor (67%), and onset was more frequent on the right side (57%). Additionally, 49% of the patients with PD had moderate to severe (M/S) MDD. Selective serotonin reuptake inhibitors were the most frequent antidepressant treatment (69%). The scores of the scales were MADRS 21.33 ± 5.49, MoCA 21.06 ± 4.65, and MMSE 26.67 ± 1.20. The females had lower MMSE scores compared to the males (p = 0.043). The patients with M/S MDD had more rigidity at the beginning of PD (p = 0.005), fewer march alterations (p = 0.023), and a greater prevalence of left-side initial disease (p = 0.037). Rigidity was associated with M/S MDD (OR 3.75 p = 0.013). MDD was slightly more frequent in the males than in the females. The MDD symptoms and cognitive impairment were worse in the female population.

Effect of onset age on the levodopa threshold dosage for dyskinesia in Parkinson's disease

INTRODUCTION

With the levodopa threshold effect for dyskinesia observed, threshold dosage of levodopa was identified in the general Parkinson's disease (PD) population. While early-onset PD (EOPD) and late-onset PD (LOPD) differ in the pathogenesis and clinical manifestations, threshold dosage of levodopa for individualized treatment remains unestablished. The objective of this study was to propose threshold dosage of levodopa in EOPD and LOPD patients, respectively.

METHODS

Data on demographic and clinical and treatment measures were collected in 539 PD patients. Patients were divided into different onset groups using 50 as the cut-off age. We used univariable and multivariable analysis to screen for risk factors for dyskinesia. Receiver operating characteristic curve was used to determine the levodopa threshold dosages for dyskinesia.

RESULTS

The prevalence of dyskinesia was 47.7% (53/111) in the EOPD group and 24.1% (103/428) in the LOPD group. Risk factors identified for dyskinesia include high levodopa daily dose and levodopa responsiveness for EOPD patients and high levodopa daily dose, long levodopa treatment duration, low body weight, use of entacapone, and high Hoehn-Yahr stage in off state for LOPD patients. The daily levodopa threshold dosages were 400 mg or 5.9 mg/kg for EOPD and 450 mg or 7.2 mg/kg for LOPD.

CONCLUSION

EOPD patients had lower levodopa threshold dosage comparing with LOPD patients. Treatment of EOPD requires stricter levodopa dose control to delay the onset of dyskinesia.

Phencynonate hydrochloride exerts antidepressant effects by regulating the dendritic spine density and altering glutamate receptor expression

Phencynonate hydrochloride (PCH) is a drug that crosses the blood-brain barrier. Cellular experiments confirmed that PCH protects against glutamate toxicity and causes only weak central inhibition and limited side effects. As shown in our previous studies, PCH alleviates depression-like behaviours induced by chronic unpredictable mild stress (CUMS). Here we administered PCH at three different doses (4, 8 and 16 mg/kg) to male rats for two continuous days after CUMS and conducted behavioural tests to assess the dose-dependent antidepressant effects of PCH and its effects on the neuroplasticity in the hippocampus and medial prefrontal cortex (mPFC). Meanwhile, we measured the spine density and expression of related proteins to illustrate the mechanism of PCH. PCH treatment (8 mg/kg) significantly alleviated depression-like behaviours induced by CUMS. All doses of PCH treatment reversed the spine loss in prelimbic and CA3 regions induced by CUMS. Kalirin-7 expression was decreased in the hippocampus and mPFC of the CUMS group. The expression of the NR1 and NR2B subunits in the hippocampus, and NR2B in mPFC are increased by CUMS. PCH treatment (8 and 16 mg/kg) reversed all of these changes of Kalirin-7 in PFC and hippocampus, as well as NR1 and NR2B expression in the hippocampus. PCH is expected to be developed as a new type of rapid antidepressant. Its antidepressant effect may be closely related to the modulation of dendritic spine density in the prelimbic and CA3 regions and the regulation of Kalilin-7 and N-methyl-D-aspartic acid receptor levels in the hippocampus.

Monoamine Levels and Parkinson's Disease Progression: Evidence From a High-Performance Liquid Chromatography Study

Parkinson’s disease (PD) is associated with dysfunction of monoamine neurotransmitter systems. We investigated changes in the levels of monoamine and their metabolites in PD patients, together with their association to clinical profiles. PD patients and age-matched control subjects (n = 40 per group) were enrolled. Using high-performance liquid chromatography (HPLC) with an electrochemical detector, levels of monoamines (dopamine, DA; norepinephrine, NE; epinephrine, EPI; and serotonin, 5-HT) were measured in plasma, while the metabolites (homovanillic acid, HVA; vanillylmandelic acid, VMA; and 5-hydroxyindoleacetic acid, 5-HIAA) were measured in urine. Plasma DA level was not significantly different between PD and control groups. PD patients had significantly higher plasma NE but lower EPI and 5-HT levels. PD patients had a significantly higher HVA/DA ratio and lower VMA/NE ratio than control subjects, while the 5-HIAA/5-HT ratio was not different between the groups. Regarding the association between monoamine levels and clinical profiles, the DA level had a negative relationship with disease duration and the 5-HT level had a negative relationship with severity of motor impairment. These findings emphasized the involvements of several neurotransmission systems and their association with clinical profiles in PD patients, demonstrated by quantification of monoamine levels in peripheral body fluids. This could benefit appropriate pharmacological treatment planning in respect of monoamine changes and might also help predict subsequent clinical symptoms.

Antidepressant-Like Properties of Intrastriatal Botulinum Neurotoxin-A Injection in a Unilateral 6-OHDA Rat Model of Parkinson's Disease

Parkinson’s patients often suffer from depression and anxiety, for which there are no optimal treatments. Hemiparkinsonian (hemi-PD) rats were used to test whether intrastriatal Botulinum neurotoxin-A (BoNT-A) application could also have antidepressant-like properties in addition to the known improvement of motor performance. To quantify depression- and anxiety-like behavior, the forced swim test, tail suspension test, open field test, and elevated plus maze test were applied to hemi-PD rats injected with BoNT-A or vehicle. Furthermore, we correlated the results in the forced swim test, open field test, and elevated plus maze test with the rotational behavior induced by apomorphine and amphetamine. Hemi-PD rats did not show significant anxiety-like behavior as compared with Sham 6-OHDA- + Sham BoNT-A-injected as well as with non-injected rats. However, hemi-PD rats demonstrated increased depression-like behaviors compared with Sham- or non-injected rats; this was seen by increased struggling frequency and increased immobility frequency. Hemi-PD rats intrastriatally injected with BoNT-A exhibited reduced depression-like behavior compared with the respective vehicle-receiving hemi-PD animals. The significant effects of intrastriatally applied BoNT-A seen in the forced swim test are reminiscent of those found after various antidepressant drug therapies. Our data correspond with the efficacy of BoNT-A treatment of glabellar frown lines in treating patients with major depression and suggest that also intrastriatal injected BoNT-A may have some antidepressant-like effect on hemi-PD.

Recent advances in the pathology of prodromal non-motor symptoms olfactory deficit and depression in Parkinson's disease: clues to early diagnosis and effective treatment

Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by movement dysfunction due to selective degeneration of dopaminergic neurons in the substantia nigra pars compacta. Non-motor symptoms of PD (e.g., sensory dysfunction, sleep disturbance, constipation, neuropsychiatric symptoms) precede motor symptoms, appear at all stages, and impact the quality of life, but they frequently go unrecognized and remain untreated. Even when identified, traditional dopamine replacement therapies have little effect. We discuss here the pathology of two PD-associated non-motor symptoms: olfactory dysfunction and depression. Olfactory dysfunction is one of the earliest non-motor symptoms in PD and predates the onset of motor symptoms. It is accompanied by early deposition of Lewy pathology and neurotransmitter alterations. Because of the correlation between olfactory dysfunction and an increased risk of progression to PD, olfactory testing can potentially be a specific diagnostic marker of PD in the prodromal stage. Depression is a prevalent PD-associated symptom and is often associated with reduced quality of life. Although the pathophysiology of depression in PD is unclear, studies suggest a causal relationship with abnormal neurotransmission and abnormal adult neurogenesis. Here, we summarize recent progress in the pathology of the non-motor symptoms of PD, aiming to provide better guidance for its effective management.

Spread spectrum SERS allows label-free detection of attomolar neurotransmitters

The quantitative label-free detection of neurotransmitters provides critical clues in understanding neurological functions or disorders. However, the identification of neurotransmitters remains challenging for surface-enhanced Raman spectroscopy (SERS) due to the presence of noise. Here, we report spread spectrum SERS (ss-SERS) detection for the rapid quantification of neurotransmitters at the attomolar level by encoding excited light and decoding SERS signals with peak autocorrelation and near-zero cross-correlation. Compared to conventional SERS measurements, the experimental result of ss-SERS shows an exceptional improvement in the signal-to-noise ratio of more than three orders of magnitude, thus achieving a high temporal resolution of over one hundred times. The ss-SERS measurement further allows the attomolar SERS detection of dopamine, serotonin, acetylcholine, γ-aminobutyric acid, and glutamate without Raman reporters. This approach opens up opportunities not only for investigating the early diagnostics of neurological disorders or highly sensitive biomedical SERS applications but also for developing low-cost spectroscopic biosensing applications.

Identification of neurotransmitters remains challenging for surface enhanced Raman spectroscopy (SERS) due to presence of noise. Here, the authors present spread spectrum SERS, which by encoding excited light and decoding SERS signals enables detection of unlabelled neurotransmitters at attomolar concentrations.

Association Between Somatization and Nonmotor Symptoms Severity in People With Parkinson Disease

OBJECTIVE

To assess the frequency of somatization and its association with motor, nonmotor symptoms, and quality of life in persons with Parkinson disease (PD).

METHODS

A cross-sectional case-control study was carried out. Assessments included the List of 90 Symptoms somatic factor (SCL-90-R SOM), Movement Disorder Society Unified Parkinson's Ratings Scale (MDS-UPDRS), Non-Motor Symptom Scale (NMSS), Montreal Cognitive Assessment (MoCA), and Parkinson Questionnaire-8 (PDQ-8).

RESULTS

A total 93 persons with PD and 93 controls were included. Somatization within the PD group was 2 times more frequent compared to the control group (43% vs 21.5%, P = .003). Persons with PD had higher NMSS total scores (48.6 ± 42.6 vs 28.3 ± 30.4, P = .001). Patients with PD with somatization had worst MDS-UPDRS, NMSS, MoCA, and PDQ-8 (all P < .05).

CONCLUSION

Somatization is more frequent in persons with PD compared to healthy controls. Somatization in PD is associated with nonmotor symptoms and worst quality of life.

Parkinson's Disease With Depression: The Correlations Between Neuroinflammatory Factors and Neurotransmitters in Cerebrospinal Fluid

Background: To explore the changes of neuroinflammatory factors in cerebrospinal fluid (CSF) and their correlation with monoamine neurotransmitters in Parkinson’s disease (PD) with depression (PD-D) patients.

Methods: Neuroinflammatory factors and neurotransmitters in CSF were measured and compared between PD with no depression (PD-ND) and PD-D groups. The relationship between PD-D and neuroinflammatory factors was studied by binary logistic regression equation, and the related factors of PD-D were adjusted. The correlations of the levels of neuroinflammatory factors and neurotransmitters in PD-D group were analyzed.

Results: The levels of tumor necrosis factor (TNF)-α in CSF from PD-D group were significantly higher and there were no significant differences in the levels of interleukin-1β, prostaglandin (PG) E₂, hydrogen peroxide (H₂O₂), and nitric oxide (NO). The 24-item Hamilton Depression Scale (HAMD-24) score was positively correlated with the level of TNF-α in CSF. Binary logistic regression showed that the OR of CSF TNF-α level was 1.035 (95% CI 1.002–1.069). The level of dopamine (DA) in CSF of PD-D group was significantly lower than that in PD-ND group. TNF-α level was negatively correlated with DA level in CSF from PD patients (r = −0.320, P = 0.003).

Conclusions: Neuroinflammatory factors, especially TNF-α, may play an important role in PD-D. It may cause damage to DA neurons and lead to the depletion of DA, which is related to the occurrence and development of PD-D.

Lower CSF homovanillic acid relates to higher burden of neuroinflammation and depression in people with HIV disease

BACKGROUND

HIV-related neuroinflammation has been proposed as a catalyst for dopaminergic dysregulation in mesocortical pathways, which may contribute to the pathogenesis of depression. Abnormalities in dopaminergic neurotransmission and depression are common in people with HIV (PWH), however the link between dopamine (DA) and depression in PWH is poorly characterized. This study investigated CSF dopaminergic biomarkers, specifically DA and its metabolite, homovanillic acid (HVA), and examined their relationship with depressive symptoms and CSF neuroinflammatory markers in PWH and HIV-seronegative (HIV-) individuals.

METHODS

Participants were 102 HIV- individuals and 123 PWH (mean age = 42) who underwent neuropsychiatric evaluations and lumbar puncture. Current depression severity was classified using the Beck Depression Inventory-II (BDI-II). CSF was assayed for DA and HVA using high performance liquid chromatography and neuroinflammatory markers using immunoassays. Linear regressions modelled BDI-II scores as a function of HIV, dopaminergic biomarker z-scores, and their interaction, controlling for psychosocial factors. Correlational analyses examined dopaminergic and neuroinflammatory relationships.

RESULTS

PWH had significantly higher BDI-II scores than HIV- participants. DA and HVA were not associated with HIV status but both significantly moderated the effect of HIV on BDI-II scores, such that PWH exhibited higher depressive symptoms than HIV- participants only at lower concentrations of HVA (z ≤ 0.06) and DA (z ≤ 0.11). In PWH only, lower HVA significantly correlated with higher BDI-II scores and higher neuroinflammation, including higher MCP-1 and IP-10.

CONCLUSIONS

Results suggest that the pathophysiology of depression in PWH differs from that in HIV- individuals. Specifically, lower central dopaminergic activity was selectively associated with greater depressive symptoms and neuroinflammation in PWH. With the rise in consideration of DA agonists for the treatment of depression, these results suggest that PWH may show a greater response to these agents than their HIV- peers.

White matter hyperintensities: a marker for apathy in Parkinson's disease without dementia?

OBJECTIVE

The objective of this study was to assess the relationship between white matter hyperintensities (WMH) and the occurrence and progression of apathy in Parkinson's disease (PD).

METHODS

We recruited patients with PD who underwent baseline evaluation, which included apathy assessment and magnetic resonance imaging (MRI) head scans. After 2.5 years of follow-up, we re-evaluated patient apathy symptoms. The severity and location of WMH were assessed with fluid-attenuated inversion recovery (FLAIR) sequences using the Fazekas visual rating scale. Logistic regression and linear regression analyses of baseline WMH characteristics were conducted to explore the potential association between apathy and WMH.

RESULTS

A total of 141 PD patients were recruited. The apathy group had a higher proportion of male patients, advanced disease, and depression, which was coupled with a lower quality of life. Morever, higher WMH severity was significantly associated with apathy. Logistic regression analyses demonstrated that WMH severity was a risk factor for apathy. In addition, linear regression analysis also suggests that apathy severity is positively correlated with baseline WMH Fazekas scales (ϐ = 0.959, P < 0.001). Baseline WMH severity was also a risk factor for apathy progression.

INTERPRETATION

WMH is associated with apathy and could be a promising marker to predict apathy progression in PD.

Chronic stress induced depressive-like behaviors in a classical murine model of Parkinson's disease

Depression occurs in around 40 % of patients with Parkinson's disease (PD) and contributes to severe disability and a poor quality of life. The underlying mechanisms and pathophysiology of depression in PD (PDD) remain obscure, due to a lack of stable animal models of PDD. In this study, we established a PDD model by inducing exposure to chronic mild (CMS) and strong stress (CSS) using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in PD mice. We detected changes in motor and non-motor symptoms, brain structure, neurotransmitters, levels of 5-HT related genes and inflammation. CMS exposed PD (PDMS) mice exhibited obviously decreased levels of neuromuscular strength and enhanced levels of inflammation, compared with that of control mice. CSS exposed MPTP (PDSS) mice exhibited the highest level of motor impairment and depression states along with the highest levels of inflammation enhancement and a decrease in the expression levels of 5-hydroxytryptamine (5-HT) related genes in all groups. Our results suggested that CSS can successfully induce stable depression like symptoms in sub-chronic MPTP PD mice and appears to be a valuable tool for investigating PDD. Furthermore, it was found that 5-HT system dysfunction may contribute to depression like symptoms in PD.

Ataxic Severity Is Positively Correlated With Fatigue in Spinocerebellar Ataxia Type 3 Patients

Background: Spinocerebellar ataxia type 3 (SCA3) is an inherited form of ataxia that leads to progressive neurodegeneration. Fatigue is a common non-motor symptom in SCA3 and other neurodegenerative diseases, such as Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Although risk factors to fatigue in these diseases have been thoroughly studied, whether or not fatigue can affect clinical phenotypes has yet to be investigated. Methods: Ninety-one molecularly confirmed SCA3 patients and 85 age- and sex-matched controls were recruited for this study. The level of fatigue was measured using the 14-item Fatigue Scale (FS-14), and the risk factors to fatigue and how fatigue correlates with clinical phenotypes were studied using multivariable linear regression models. Results: We found that the severity was significantly higher in the SCA3 group than in the control group (9.30 ± 3.04% vs. 3.94 ± 2.66, P = 0.000). Daytime somnolence (β = 0.209, P = 0.002), severity of ataxia (β = 0.081, P = 0.006), and poor sleep quality (β = 0.187, P = 0.037) were found to have a positive relationship with fatigue. Although fatigue had no relationship with age at onset or ataxic progression, we found that it did have a positive relationship with the severity of ataxia (β = 7.009, P = 0.014). Conclusions: The high level of fatigue and the impact of fatigue on the clinical manifestation of SCA3 patients suggest that fatigue plays a large role in the pathogenesis of SCA3, thus demonstrating the need for intervention and treatment options in this patient cohort.

Risks of Sulpiride-Induced Parkinsonism in Peptic Ulcer and Gastroesophageal Reflux Disease Patients in Taiwan: A Nationwide Population-Based Study

BACKGROUND

Sulpiride is a highly selective dopamine D2 receptor antagonist and is commonly used in psychiatric disorders, Tourette syndrome, peptic ulcer disease (PUD), and gastroesophageal reflux disease (GERD). However, sulpiride has been recognized as a potential cause of drug-induced parkinsonism (DIP) for a long time. In this study, we aimed to focus on analysis of sulpiride-induced parkinsonism (SIP) in PUD and GERD patients based on a nationwide population.

METHODS

Data were obtained from the Taiwan's National Health Insurance Research Database. The study enrolled 5,275 PUD or GERD patients, of whom were divided into two groups, based on their exposure (1,055 cases) or non-exposure (4,220 cases) to sulpiride.

RESULTS

During the study period (2000-2012), the incidence rate of parkinsonism was 261.5 and 762.2 per 100,000 person-years in the control and sulpiride-treated groups, respectively. For patients with at least 14 days of prescription for sulpiride, the adjusted hazard ratio (aHR) was 2.89, 95% confidence interval (CI): 2.04-4.11. Patients with age more than 65 years (aHR = 4.99, 95% CI = 2.58-9.65), hypertension (aHR = 2.39, 95% CI = 1.49-3.82), depression (aHR = 2.00, 95% CI = 1.38-2.91), and anxiety (aHR = 1.45, 95% CI = 1.01-2.09) had significant higher risk of developing parkinsonism. An average annual cumulative sulpiride dose > 1,103 mg was accompanied by the greatest risk of SIP; sulpiride use for ≥ 9 days is a cut-off point for predicting future SIP.

CONCLUSION

At the population level, sulpiride may be frequently prescribed and apparently effective for PUD and GERD. SIP is associated with older age, hypertension, depression or anxiety comorbidities. Physicians should be aware of the neurogenic adverse effects, even when the drug is only used in low-dose or a short duration.