Interactions Between the Serotonergic and Other Neurotransmitter Systems in the Basal Ganglia: Role in Parkinson's Disease and Adverse Effects of L-DOPA

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. However, other non-dopaminergic neuronal systems such as the serotonergic system are also involved. Serotonergic dysfunction is associated with non-motor symptoms and complications, including anxiety, depression, dementia, and sleep disturbances. This pathology reduces patient quality of life. Interaction between the serotonergic and other neurotransmitters systems such as dopamine, noradrenaline, glutamate, and GABA controls the activity of striatal neurons and are particularly interesting for understanding the pathophysiology of PD. Moreover, serotonergic dysfunction also causes motor symptoms. Interestingly, serotonergic neurons play an important role in the effects of L-DOPA in advanced PD stages. Serotonergic terminals can convert L-DOPA to dopamine, which mediates dopamine release as a "false" transmitter. The lack of any autoregulatory feedback control in serotonergic neurons to regulate L-DOPA-derived dopamine release contributes to the appearance of L-DOPA-induced dyskinesia (LID). This mechanism may also be involved in the development of graft-induced dyskinesias (GID), possibly due to the inclusion of serotonin neurons in the grafted tissue. Consistent with this, the administration of serotonergic agonists suppressed LID. In this review article, we summarize the interactions between the serotonergic and other systems. We also discuss the role of the serotonergic system in LID and if therapeutic approaches specifically targeting this system may constitute an effective strategy in PD

Sustained Stable Disease with Capecitabine plus Bevacizumab in Metastatic Appendiceal Adenocarcinoma: A Case Report.

In a patient who had been diagnosed in 2006 with appendiceal adenocarcinoma with peritoneal metastases after an incomplete surgery, palliative chemotherapy was administered. First-line treatment with 5-fluorouracil, leucovorin and oxaliplatin (FOLFOX) and second-line treatment including 5-fluorouracil, leucovorin and irinotecan (FOLFIRI) plus panitumumab showed inefficiency in controlling disease progression. Third-line chemotherapy combining capecitabine plus bevacizumab was started, achieving good control of the tumour growth and a minor response in the second computed tomography scan. We decided to maintain the treatment, although forced bevacizumab "breaks" were necessary due to unexpected adverse events, with the patient suffering disease progression every time bevacizumab was stopped and reaching minor response again once the antiangiogenic treatment was reintroduced. During more than 10 years after starting third-line treatment, the patient maintained good performance status and disease stability with this "up and down" management until January 2019, when a neurological adverse event during bevacizumab infusion drove us to abandon it definitely

Dramatic Response of Leptomeningeal Carcinomatosis to Nivolumab in PD-L1 Highly Expressive Non-small Cell Lung Cancer: A Case Report

In a patient who had been diagnosed of located squamous cell lung carcinoma, pneumonectomy, and adjuvant chemotherapy were performed. Brain recurrence and subsequent lung metastatic disease were uncontrolled by neurosurgery, holocranial radiotherapy, and first-line chemotherapy. In August 2015, appearance of leptomeningeal carcinomatosis triggered severe clinical deterioration and threatened the patient's life. Anti-PD1 immune checkpoint inhibitor Nivolumab was initiated in an attempt to stop tumor growth, achieving a spectacular brain and pulmonary complete response and clinical improvement, without serious adverse effects. High expression PD-L1 level (100%) was found in the pathological tissue sample. Nivolumab was maintained for more than 2 years and stopped in December 2017 after 28 months of treatment, with no disease evidence. More than 3 years after its onset, the patient maintains an outstanding PS with complete tumor response and no evidence of disease in last surveillance CT scan and brain MRI

Safinamide Improves Non-Motor Symptoms Burden in Parkinson’s Disease: An Open-Label Prospective Study

Some studies observed a benefit of Parkinson’s disease (PD) patients after treatment with safinamide in some non-motor symptoms (NMSs). The aim of this study was to analyze the effectiveness of safinamide on NMS burden in PD. SAFINONMOTOR (an open-label study of the effectiveness of safinamide on non-motor symptoms in Parkinson’s disease patients) is a prospective open-label single-arm study conducted in five centers from Spain. The primary efficacy outcome was the change from baseline (V1) to the end of the observational period (6 months) (V4) in the non-motor symptoms scale (NMSS) total score. Between May/2019 and February/2020 50 patients were included (age 68.5 ± 9.12 years; 58% females; 6.4 ± 5.1 years from diagnosis). At 6 months, 44 patients completed the follow-up (88%). The NMSS total score was reduced by 38.5% (from 97.5 ± 43.7 in V1 to 59.9 ± 35.5 in V4; p p = 0.002), mood/apathy (−57.9%; p p = 0.026), gastrointestinal symptoms (−33%; p = 0.010), urinary symptoms (−28.3%; p = 0.003), and pain/miscellaneous (−43%; p p < 0.0001). A total of 21 adverse events in 16 patients (32%) were reported, 5 of which were severe (not related to safinamide). Dyskinesias and nausea were the most frequent (6%). Safinamide is well tolerated and improves NMS burden and QoL in PD patients with severe or very severe NMS burden at 6 months