Deep brain stimulation improves central nervous system inflammation in Parkinson's disease: Evidence and perspectives

Unlocking the brain's code: The crucial role of post-translational modifications in neurodevelopment and neurological function

Post-translational modifications (PTMs) represent a crucial regulatory mechanism in the brain, influencing various processes, including neurodevelopment and neurological function. This review discusses the effects of PTMs, such as phosphorylation, ubiquitination, acetylation, and glycosylation, on neurodevelopment and central nervous system functionality. Although neurodevelopmental processes linked to PTMs are complex, proteins frequently converge within shared pathways. These pathways encompass neurodevelopmental processes, signaling mechanisms, neuronal migration, and synaptic connection formation, where PTMs act as dynamic regulators, ensuring the precise execution of brain functions. A detailed investigation of the fundamental mechanisms governing these pathways will contribute to a deeper understanding of nervous system functions and facilitate the identification of potential therapeutic targets. A thorough examination of the PTM landscape holds significant potential, not only in advancing knowledge but also in developing treatments for various neurological disorders.

Immunomodulatory effects of invasive and non-invasive brain stimulation in Parkinson's disease

Accumulating evidence points to a critical role of the immune system in the neurodegenerative process in Parkinson's disease (PD). This late knowledge has revolutionised our understanding of the pathogenetic mechanisms underlying PD and has opened new avenues toward disease-modifying rather than dopamine-replacement therapeutic approaches. When pharmacological treatments fail to adequately alleviate clinical symptoms, brain stimulation techniques are taken into consideration. Deep brain stimulation (DBS) constitutes the most common method for invasive brain stimulation, while the non-invasive brain stimulation paradigms comprise among others repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS). How each brain stimulation paradigm interferes with disease pathogenesis still remains elusive. In light of recent evidence supporting the involvement of the immune system in PD, a question that arises is whether brain stimulation techniques have an immunomodulatory potential. Here, we summarize the existing knowledge and provide mechanistic insights that should foster future research. Overall, it appears that DBS and rTMS can modulate both the central and the peripheral component of the immune system and can lead to clinical improvement through immunosuppressive/anti-inflammatory mechanisms. The paucity of evidence for tDCS and tACS precludes any conclusions and highlights the necessity of more mechanistic studies focusing on their immunomodulatory potential, if any. Any pre-clinical findings warrant further clinical validation using human in vivo markers and post-mortem human brain tissue. Unravelling the mechanisms that underpin the beneficial therapeutic effects of brain stimulation in PD patients can contribute substantially to the fine-tuning of the current stimulation protocols and pave the way for more efficient and clinically meaningful neuromodulation paradigms.

Progress on Direct Regulation of Systemic Immunity by the Central Nervous System

This article reviews the research progress on the direct regulation of the immune system by the central nervous system (CNS). The traditional "neuro-endocrine-immune" network model has confirmed the close connection between the CNS and the immune system. However, due to the complex mediating role of the endocrine system, its application in clinical treatment is limited. In recent years, the direct regulation of the peripheral immune system through the CNS has provided new methods for the clinical treatment of neuroimmune-related diseases. This article analyzes the changes in the peripheral immune system after CNS injury and summarizes the effects of various stimulation methods, including transcranial magnetic stimulation, transcranial electrical stimulation, deep brain stimulation, spinal cord stimulation, and vagus nerve stimulation, on the peripheral immune system. Additionally, it explores the clinical research progress and future development directions of these stimulation methods. It is proposed that these neural regulation techniques exhibit positive effects in reducing peripheral inflammation, protecting immune cells and organ functions, and improving immunosuppressive states, providing new perspectives and therapeutic potential for the treatment of immune-related diseases.

Deep brain stimulation halts Parkinson's disease-related immune dysregulation in the brain and peripheral blood

Immune dysregulation in the brain and periphery is thought to contribute to the detrimental neurodegeneration that occurs in Parkinson's disease (PD). Identifying mechanisms to reverse this dysregulation is key to developing disease-altering therapeutics for this currently incurable disease. Here we utilized the longitudinal data from the Parkinson's Progression Marker Initiative to demonstrate that circulating lymphocytes progressively decline in PD and can be used to predict future motor symptom progression. Deep brain stimulation (DBS), which is used as a symptomatic treatment, could halt this progressive decline. By analyzing specific immune populations from a second cohort of patients, we could show that DBS causes a shift from the pro-inflammatory CD4+ T helper 17 cells driving neurodegeneration to anti-inflammatory CD4+ regulatory T cells. RNA-sequencing and immunohistochemistry in the brain of the A53T alpha-synuclein rat model of PD revealed that DBS also decreases neuroinflammation. These data suggest a potential disease-altering role for DBS by halting inflammatory processes.

Multiomics approach discloses lipids and metabolites profiles associated to Parkinson's disease stages and applied therapies

Profiling circulating lipids and metabolites in Parkinson's disease (PD) patients could be useful not only to highlight new pathways affected in PD condition but also to identify sensitive and effective biomarkers for early disease detection and potentially effective therapeutic interventions. In this study we adopted an untargeted omics approach in three groups of patients (No L-Dopa, L-Dopa and DBS) to disclose whether long-term levodopa treatment with or without deep brain stimulation (DBS) could reflect a characteristic lipidomic and metabolomic signature at circulating level. Our findings disclosed a wide up regulation of the majority of differentially regulated lipid species that increase with disease progression and severity. We found a relevant modulation of triacylglycerols and acyl-carnitines, together with an altered profile in adiponectin and leptin, that can differentiate the DBS treated group from the others PD patients. We found a highly significant increase of exosyl ceramides (Hex2Cer) and sphingoid bases (SPB) in PD patients mainly in DBS group (p < 0.0001), which also resulted in a highly accurate diagnostic performance. At metabolomic level, we found a wide dysregulation of pathways involved in the biosynthesis and metabolism of several amino acids. The most interesting finding was the identification of a specific modulation of L-glutamic acid in the three groups of patients. L-glutamate levels increased slightly in No L-Dopa and highly in L-Dopa patients while decreased in DBS, suggesting that DBS therapy might have a beneficial effect on the glutamatergic cascade. All together, these data provide novel insights into the molecular and metabolic alterations underlying PD therapy and might be relevant for PD prediction, diagnosis and treatment.

CCR5 and inflammatory storm

Chemokines and their corresponding receptors play crucial roles in orchestrating inflammatory and immune responses, particularly in the context of pathological conditions disrupting the internal environment. Among these receptors, CCR5 has garnered considerable attention due to its significant involvement in the inflammatory cascade, serving as a pivotal mediator of neuroinflammation and other inflammatory pathways associated with various diseases. However, a notable gap persists in comprehending the intricate mechanisms governing the interplay between CCR5 and its ligands across diverse and intricate inflammatory pathologies. Further exploration is warranted, especially concerning the inflammatory cascade instigated by immune cell infiltration and the precise binding sites within signaling pathways. This study aims to illuminate the regulatory axes modulating signaling pathways in inflammatory cells by providing a comprehensive overview of the pathogenic processes associated with CCR5 and its ligands across various disorders. The primary focus lies on investigating the pathomechanisms associated with CCR5 in disorders related to neuroinflammation, alongside the potential impact of aging on these processes and therapeutic interventions. The discourse culminates in addressing current challenges and envisaging potential future applications, advocating for innovative research endeavors to advance our comprehension of this realm.

The severity assessment of Parkinson's disease based on plasma inflammatory factors and third ventricle width by transcranial sonography

BACKGROUND

Predicting Parkinson's disease (PD) can provide patients with targeted therapies. However, disease severity can be roughly evaluated in clinical practice based on the patient's symptoms and signs.

OBJECTIVE

The current study attempted to explore the factors linked with PD severity and construct a predictive model.

METHOD

The PD patients and healthy controls were recruited from our study center while recording their basic demographic information. The serum inflammatory markers levels, such as Cystatin C (Cys C), C-reactive protein (CRP), RANTES (regulated on activation, normal T cell expressed and secreted), Interleukin-10 (IL-10), and Interleukin-6 (IL-6) were determined for all the participants. PD patients were categorized into early and mid-advanced groups based on the Hoehn and Yahr (H-Y) scale and evaluated using PD-related scales. LASSO logistic regression analysis (Model C) helped select variables based on clinical scale evaluations, serum inflammatory factor levels, and transcranial sonography measurements. The optimal harmonious model coefficient λ was determined via 10-fold cross-validation. Moreover, Model C was compared with multivariate (Model A) and stepwise (Model B) logistic regression. The area under the curve (AUC) of a receiver operator characteristic (ROC), brier score, calibration curve, and decision curve analysis (DCA) helped determine the discrimination and calibration of the predictive model, followed by configuring a forest plot and column chart.

RESULTS

The study included 113 healthy individuals and 102 PD patients, with 26 early and 76 mid-advanced patients. Univariate analysis of variance screened out statistically significant differences among inflammatory markers Cys C and RANTES. The average Cys C level in the mid-advanced stage was significantly higher than in the early stage (p < 0.001) but not for RANTES (p = 0.740). The LASSO logistic regression model (λ.1se = 0.061) associated with UPDRS-I, UPDRS-II, UPDRS-III, HAMA, PDQ-39, and Cys C as the included independent variables revealed that the Model C discrimination and calibration (AUC = 0.968, Brier = 0.049) were superior to Model A (AUC = 0.926, Brier = 0.079) and Model B (AUC = 0.929, Brier = 0.071) models.

CONCLUSION

The study results show multiple factors are linked with PD assessment. Moreover, the inflammatory marker Cys C and transcranial sonography measurement could objectively predict PD symptom severity, helping doctors monitor PD evolution in patients while targeting interventions.

Cytokine activity in Parkinson's disease

The contribution of the immune system to the pathophysiology of neurodegenerative Parkinson's disease (PD) is increasingly being recognised, with alterations in the innate and adaptive arms of the immune system underlying central and peripheral inflammation in PD. As chief modulators of the immune response, cytokines have been intensely studied in the field of PD both in terms of trying to understand their contribution to disease pathogenesis, and if they may comprise much needed therapeutic targets for a disease with no current modifying therapy. This review summarises current knowledge on key cytokines implicated in PD (TNFα, IL-6, IL-1β, IL-10, IL-4 and IL-1RA) that can modulate both pro-inflammatory and anti-inflammatory effects. Cytokine activity in PD is clearly a complicated process mediated by substantial cross-talk of signalling pathways and the need to balance pro- and anti-inflammatory effects. However, understanding cytokine activity may hold promise for unlocking new insight into PD and how it may be halted.

Neuromodulation for Brain Tumors: Myth or Reality? A Narrative Review

In recent years, research on brain cancers has turned towards the study of the interplay between the tumor and its host, the normal brain. Starting from the establishment of a parallelism between neurogenesis and gliomagenesis, the influence of neuronal activity on the development of brain tumors, particularly gliomas, has been partially unveiled. Notably, direct electrochemical synapses between neurons and glioma cells have been identified, paving the way for new approaches for the cure of brain cancers. Since this novel field of study has been defined "cancer neuroscience", anticancer therapeutic approaches exploiting these discoveries can be referred to as "cancer neuromodulation". In the present review, we provide an up-to-date description of the novel findings and of the therapeutic neuromodulation perspectives in cancer neuroscience. We focus both on more traditional oncologic approaches, aimed at modulating the major pathways involved in cancer neuroscience through drugs or genetic engineering techniques, and on electric stimulation proposals; the latter is at the cutting-edge of neuro-oncology.