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Abstract Background Parkinson’s disease is characterized by a continuous loss of neurons within the substantia nigra (SN) leading to a depletion of dopamine. Within the adult SN as a non-neurogenic region, cells with mainly oligodendrocytic precursor characteristics, expressing the neuro-glial antigen-2 (NG2) are continuously generated. Proliferation of these cells is altered in animal models of Parkinson’s disease (PD). Exercise and environmental enrichment re-increase proliferation of NG2+ cells in PD models, however, a possible mechanistic role of dopamine for this increase is not completely understood. NG2+ cells can differentiate into oligodendrocytes but also into microglia and neurons as observed in vitro suggesting a possible hint for endogenous regenerative capacity of the SN. We investigated the role of dopamine in NG2-generation and differentiation in the adult SN stimulated by physical activity and environmental enrichment. Results We used the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-model for dopamine depletion and analysed newborn cells in the SN at different maturation stages and time points depending on voluntary physical activity, enriched environment and levodopa-treatment. We describe an activity- induced increase of new NG2-positive cells and also mature oligodendrocytes in the SN of healthy mice. Running and enriched environment refused to stimulate NG2-generation and oligodendrogenesis in MPTP-mice, an effect which could be reversed by pharmacological levodopa-induced rescue. Conclusion We suggest dopamine being a key regulator for activity-induced generation of NG2-cells and oliogodendrocytes in the SN as a potentially relevant mechanism in endogenous nigral cellular plasticity.

Background Neurotoxicity is a frequent side effect of cytotoxic chemotherapy and affects a large number of patients. Despite the high medical need, few research efforts have addressed the impact of cytotoxic agents on cognition (ie, postchemotherapy cognitive impairment; PCCI). One unsolved question is whether individual cytotoxic drugs have differential effects on cognition. We thus examine the current state of research regarding PCCI. Neurological symptoms after targeted therapies and immunotherapies are not part of this review. Methods A literature search was conducted in the PubMed database, and 1215 articles were reviewed for predefined inclusion and exclusion criteria. Thirty articles were included in the systematic review. Results Twenty-five of the included studies report significant cognitive impairment. Of these, 21 studies investigated patients with breast cancer. Patients mainly received combinations of 5-fluorouracil, epirubicin, cyclophosphamide, doxorubicin, and taxanes (FEC/FEC-T). Five studies found no significant cognitive impairment in chemotherapy patients. Of these, 2 studies investigated patients with colon cancer receiving 5-fluorouracil and oxaliplatin (FOLFOX). Independent risk factors for PCCI were patient age, mood alterations, cognitive reserve, and the presence of apolipoprotein E e4 alleles. Conclusions There is evidence that certain chemotherapy regimens cause PCCI more frequently than others as evidenced by 21 out of 23 studies in breast cancer patients (mainly FEC-T), whereas 2 out of 3 studies with colon cancer patients (FOLFOX) did not observe significant changes. Further studies are needed defining patient cohorts by treatment protocol in addition to cancer type to elucidate the effects of individual cytotoxic drugs on cognitive functions. [ABSTRACT FROM AUTHOR]

Neurologic immune-related adverse events (nirAEs) represent rare, yet severe side effects associated with immune checkpoint inhibitor (ICI) therapy. Given the absence of established diagnostic biomarkers for nirAEs, we aimed to evaluate the diagnostic utility of serum Neurofilament Light Chain (NfL) and Glial Fibrillary Acidic Protein (GFAP). Fifty-three patients were included at three comprehensive cancer centers, of these 20 patients with manifest nirAEs and 11 patients with irHypophysitis. Controls included patients without any irAE (n = 8) and other irAEs (n = 14). Using a single-molecule enzyme-linked immunosorbent assay (Simoa), serum levels were measured prior to, during and after the manifestation of (n)irAEs in 80 samples. Symptom severity of the (n)irAEs was graded according to the Common Criteria for Adverse Events (CTCAE) version 5.0. Serum NfL levels were significantly higher in the nirAE group (n = 20) compared to irHypophysitis (n = 11; p = .0025) and controls (n = 22; p = .0384). Subgroup analysis demonstrated a significant elevation of NfL in nirAEs of the peripheral nerves (PNirAE) in contrast to neuromuscular syndromes (NMirAE) (p = .0260). GFAP levels were highest in patients with nirAE affecting the central nervous system (CNSirAE) compared to PNirAE and NMirAE (p = .0064). Symptom severity of nirAEs was associated with increased levels of NfL and GFAP (p = .0069, .0092). Individuals with elevated NfL levels exhibited less favorable outcomes of the (n)irAEs (p = .0199). Measurement of NfL and GFAP may be helpful for the differentiation of the broad spectrum of nirAEs and may serve as an indicator of symptom severity. Further investigation is needed to evaluate their potential as diagnostic and prognostic biomarkers., (© 2025 The Author(s). International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

Background: Chemotherapy-induced cognitive impairment (CICI) is a well-recognized side effect of breast cancer treatment. However, prospective long-term evaluations of CICI using standardized neuropsychological tests are scarce., Patients and Methods: This prospective longitudinal cohort study investigated cognitive dysfunction and its impact on quality of life and everyday functioning in patients with breast cancer receiving first-line chemotherapy compared to patients with breast cancer without chemotherapy. Assessment occurred prior to chemotherapy, postchemotherapy (median 6 months), and 2-3 years later. We used standardized neuropsychological tests, questionnaires, and scales to assess patients' quality of life and functioning. Additionally, serum analysis for neurodegenerative markers and autoantibodies was conducted., Results: We included n = 53 patients. Overall cognitive function declined statistically significantly (P = .046) postchemotherapy compared to control patients, mostly driven by a reduced figural memory (P = .011). Patients who received chemotherapy showed a greater reduction in quality of life (increased fatigue symptoms, P = .023; reduced Karnofsky index, P < .001); however, without a statistically significant effect on cognitive decline. The neurodegenerative markers Neurofilament light chain (NfL) and phosphorylated Neurofilament heavy chain (pNfH) increased statistically significantly (P < .001) postchemotherapy and pNfH correlated with overall cognitive function. After 2-3 years, both cognitive performance and quality of life were comparable between chemotherapy-treated and control patients., Conclusion: Our findings suggest that chemotherapy statistically significantly contributes to overall cognitive dysfunction in patients with breast cancer, which disappears after 2-3 years, indicating a recovery in both objectively measurable cognitive function and subjective quality of life. Future research should examine larger sample sizes and explore screening indicators, particularly pNfH., (© The Author(s) 2024. Published by Oxford University Press.)