High lithium levels in tobacco may account for reduced incidences of both Parkinson's disease and melanoma in smokers through enhanced ß-catenin-mediated activity.

Parkinson's disease (PD) patients have higher rates of melanoma and vice versa, observations suggesting that the two conditions may share common pathogenic pathways. ß-Catenin is a transcriptional cofactor that, when concentrated in the nucleus, upregulates the expression of canonical Wnt target genes, such as Nurr1, many of which are important for neuronal survival. ß-Catenin-mediated activity is decreased in sporadic PD as well as in leucine-rich repeat kinase 2 (LRRK2) and ß-glucosidase (GBA) mutation cellular models of PD, which is the most common genetic cause of and risk for PD, respectively. In addition, ß-catenin expression is significantly decreased in more aggressive and metastatic melanoma. Multiple observational studies have shown smokers to have significantly lower rates of PD as well as melanoma implying that tobacco may contain one or more elements that protect against both conditions. In support, smoker's brains have significantly reduced levels of α-synuclein, a pathological intracellular protein found in PD brain and melanoma cells. Tobacco contains very high lithium levels compared to other plants. Lithium has a broad array of neuroprotective actions, including enhancing autophagy and reducing intracellular α-synuclein levels, and is effective in both neurotoxin and transgenic preclinical PD models. One of lithium's neuroprotective actions is enhancement of ß-catenin-mediated activity leading to increased Nurr1 expression through its ability to inhibit glycogen synthase kinase-3 ß (GSK-3ß). Lithium also has anti-proliferative effects on melanoma cells and the clinical use of lithium is associated with a reduced incidence of melanoma as well as reduced melanoma-associated mortality. This is the first known report hypothesizing that inhaled lithium from smoking may account for the associated reduced rates of both PD and melanoma and that this protection may be mediated, in part, through lithium-induced GSK-3ß inhibition and consequent enhanced ß-catenin-mediated activity. This hypothesis could be directly tested in clinical trials assessing lithium therapy's ability to affect ß-catenin-mediated activity and slow disease progression in patients with PD or melanoma.

Ventral posterior substantia nigra iron increases over 3 years in Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is characterized in part by the progressive accumulation of iron within the substantia nigra (SN); however, its spatial and temporal dynamics remain relatively poorly understood. OBJECTIVES: The objective of this study was to investigate spatial patterns and temporal evolution of SN iron accumulation in PD. METHODS: A total of 18 PD patients (mean disease duration = 6.2 years) receiving dopaminergic therapy and 16 healthy controls were scanned with 3T MRI at baseline and 3 years later using quantitative susceptibility mapping, an indirect marker of iron content. Iron was assessed separately in the posterior SN and anterior SN at the ventral and dorsal levels of the SN. The results were corrected for the false discovery rate. RESULTS: A significant group effect was found for the ventral posterior SN (P < .001) and anterior SN (P = .042) quantitative susceptibility mapping as well as significant group x time interaction effects (P = .02 and P = .043, respectively). In addition, a significant intragroup change during 3 years of follow-up was found only in the ventral posterior SN of PD (P = .012), but not healthy controls. No significant effects were detected for any dorsal SN measures. No associations were identified with clinical measures. CONCLUSIONS: We found both cross-sectional and longitudinal SN iron changes to be confined to its more ventral location in PD. Because pathology studies also show the ventral SN to degenerate early and to the greatest extent in PD, the assessment of iron levels by quantitative susceptibility mapping in this area may potentially represent a disease progression biomarker in PD. © 2019 International Parkinson and Movement Disorder Society.

Targeting kinases in Parkinson's disease: A mechanism shared by LRRK2, neurotrophins, exenatide, urate, nilotinib and lithium.

Several kinases have been implicated in the pathogenesis of Parkinson's disease (PD), most notably leucine-rich repeat kinase 2 (LRRK2), as LRRK2 mutations are the most common genetic cause of a late-onset parkinsonism that is clinically indistinguishable from sporadic PD. More recently, several other kinases have emerged as promising disease-modifying targets in PD based on both preclinical studies and clinical reports on exenatide, the urate precursor inosine, nilotinib and lithium use in PD patients. These kinases include protein kinase B (Akt), glycogen synthase kinases-3ß and -3α (GSK-3ß and GSK-3α), c-Abelson kinase (c-Abl) and cyclin-dependent kinase 5 (cdk5). Activities of each of these kinases are involved either directly or indirectly in phosphorylating tau or increasing α-synuclein levels, intracellular proteins whose toxic oligomeric forms are strongly implicated in the pathogenesis of PD. GSK-3ß, GSK-3α and cdk5 are the principle kinases involved in phosphorylating tau at sites critical for the formation of tau oligomers. Exenatide analogues, urate, nilotinib and lithium have been shown to affect one or more of the above kinases, actions that can decrease the formation and increase the clearance of intraneuronal phosphorylated tau and α-synuclein. Here we review the current preclinical and clinical evidence supporting kinase-targeting agents as potential disease-modifying therapies for PD patients enriched with these therapeutic targets and incorporate LRRK2 physiology into this novel model.

Nighttime awakenings responding to gabapentin therapy in late premenopausal women: a case series.

Insomnia related to nighttime awakenings is known to be more prevalent in women than men. Three cases are presented here of late premenopausal women experiencing frequent nighttime awakenings that responded well to bedtime treatment with gabapentin. In one case, what started as isolated nighttime awakenings slowly progressed to awakenings accompanied by typical menopausal night sweats. This led to the theory that the initial isolated nighttime awakenings in this patient may have been secondary to a menopausal etiology related to low serum estradiol levels. In the subsequent 2 cases, early follicular phase serum estradiol was confirmed to be low. It is theorized that isolated nighttime awakenings in some premenopausal women may be caused by low serum estradiol, triggering events physiologically related to menopausal night sweats. Further research is needed to determine if low early follicular phase serum estradiol is associated with nighttime awakenings in premenopausal women not experiencing night sweats.

Minimum trial duration to reasonably assess long-term efficacy of nonhormonal hot flash therapies.

BACKGROUND: Because hot flashes usually persist for years after menopause, a clinically meaningful hot flash therapy needs to have long-term efficacy; however, it is unclear for how long a therapy needs to be compared with a placebo before long-term efficacy can be reasonably deduced. The Food and Drug Administration (FDA) requires a 12-week treatment period for industry-initiated hot flash trials, whereas most academic-initiated trials have ranged from 4 to 12 weeks. We have focused on reviewing nonhormonal hot flash trials to identify inadequate trial durations as a guide toward deducing adequate trial duration to reasonably assess for long-term efficacy. METHODS: An electronic database search of MEDLINE, Web of Science, and PsycINFO was performed from 1966 to May 2009 to identify target studies showing a nonhormonal hot flash therapy to be effective at early time points only to become ineffective at later time points (i.e., showing short-term but not long-term efficacy) in a randomized controlled trial (RCT). The longest early time point of efficacy from the target studies plus 1 additional week would be considered the minimum treatment duration necessary to assess for long-term efficacy. RESULTS: Of 2518 citations, 54 RCTs met our inclusion criteria, from which 3 target studies were identified. These 3 target studies evaluated Bellergal Retard (Sandoz, East Hanover, NJ), soy, and venlafaxine and showed times of 2, 6, and 7 weeks, respectively, when the nonhormonal compound last demonstrated efficacy before subsequently losing efficacy in a single RCT. CONCLUSIONS: This analysis supports a hot flash RCT duration of at least 8 weeks to reasonably assess a nonhormonal compound's long-term efficacy.

Newer antidepressants and gabapentin for hot flashes: an individual patient pooled analysis.

PURPOSE: Nonhormonal treatment options have been investigated as treatments for hot flashes, a major clinical problem in many women. Starting in 2000, a series of 10 individual double-blind placebo-controlled studies has evaluated newer antidepressants and gabapentin for treating hot flashes. This current project was developed to conduct an individual patient pooled analysis of the data from these published clinical trials. PATIENTS AND METHODS: Individual patient data were collected from the various study investigators who published their study results between 2000 and 2007. Between-study heterogeneity for study characteristics and patient populations was tested via chi2 tests before a pooled analysis. The primary end point, the change in hot flash activity from baseline to week 4, for each agent was calculated via both weighted and unweighted approaches, using the size of the study as the weight. Basic summary statistics were produced for hot flash score and frequency using the following three statistics: raw change, percent reduction, and whether or not a 50% reduction was achieved. RESULTS: This study included seven trials of newer antidepressants and three trials of gabapentin. The optimal doses (defined by individual study results) of the newer antidepressants paroxetine, venlafaxine, fluoxetine, and sertraline decreased hot flash scores by 41%, 33%, 13%, and 3% to 18% compared with the corresponding placebo arms, respectively. The three gabapentin trials decreased hot flashes by 35% to 38% compared with the corresponding placebo arms. CONCLUSION: Some newer antidepressants and gabapentin, within 4 weeks of therapy initiation, decrease hot flashes more than placebo.

Gabapentin, estrogen, and placebo for treating hot flushes: a randomized controlled trial.

OBJECTIVE: To compare the efficacy of gabapentin, estrogen, and placebo in the treatment of hot flushes. METHODS: We performed a randomized, double-blind, placebo-controlled trial of 60 postmenopausal women to assess the efficacy of estrogen and gabapentin in the treatment of moderate-to-severe hot flushes. Participants were randomly assigned to receive either 0.625 mg/d of conjugated estrogens (n = 20), placebo (n = 20), or gabapentin titrated to 2,400 mg/d (n = 20) for 12 weeks. Participants recorded frequency and severity of baseline hot flushes on a hot flush diary for 2 weeks before randomization and for 12 weeks after randomization. The primary outcome measure was the weekly hot flush composite score, which takes into account both severity and frequency of hot flushes. Secondary outcome measures were differences in pre- and posttreatment scores pertaining to depression (Zung Depression Scale) and other climacteric symptoms (Greene Climacteric Scale). RESULTS: Intention-to-treat analysis showed that the reduction in the hot flush composite score for both estrogen (72%, P = .016) and gabapentin (71%, P = .004) was greater than the reduction associated with placebo (54%) at the conclusion of the 12th week. The extent of reduction in hot flush composite score, however, was not significantly different between estrogen and gabapentin (P = .63). No differences were seen between groups in the Zung Depression Scale, or in any of the Greene Climacteric subscales except for the Somatic Symptom cluster, which was significantly greater in the gabapentin arm than in the placebo arm. Despite a lack of group differences in adverse events, the Headache, Dizziness, and Disorientation cluster appeared with greater frequency in the gabapentin group. Estimation of the number needed to harm in this cluster suggests that these symptoms may occur with every fourth patient treated with gabapentin. CONCLUSION: Despite the small scale of this study, gabapentin appears to be as effective as estrogen in the treatment of postmenopausal hot flushes. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov, NCT 00276081. LEVEL OF EVIDENCE: I.

Responsiveness of life-threatening refractory emesis to gabapentin-scopolamine therapy following posterior fossa surgery. Case report.

Craniotomy-associated chronic emesis can be refractory to currently approved antiemetic therapy. The authors describe a man who suffered 4 weeks of severe refractory emesis, failure to thrive, and a 40-lb weight loss after he underwent resection of a posterior fossa cholesteatoma. The patient experienced complete resolution of emesis and anorexia in response to combined gabapentin-scopolamine therapy. This case provides anecdotal evidence for the use of gabapentin-scopolamine therapy in patients with chronic, refractory nausea and emesis, particularly following posterior fossa surgery, during which medullary nausea and emesis centers may be affected.

Hot flashes refractory to HRT and SSRI therapy but responsive to gabapentin therapy.

There is a need for alternative therapies for hot flashes, as hormone replacement therapy (HRT) is associated with increased rates of breast cancer and heart disease, and some women fail to respond to HRT. A 32-year-old woman with surgically-induced menopause experienced 20-30 severe hot flashes per day and failed to respond to various formulations of HRT and selective serotonin reuptake inhibitor (SSRI) therapy for 17 years. She markedly responded to gabapentin therapy. Gabapentin, SSRIs, and estrogen may act at different cellular targets in the treatment of hot flashes.

Pilot study using gabapentin for tamoxifen-induced hot flashes in women with breast cancer.

In this pilot study, 22 women with breast cancer on tamoxifen therapy with at least two hot flashes a day took oral gabapentin at 300 mg three times a day for 4 weeks. The 16 women who completed the study had a mean decrease in hot flash duration of 73.6% (P = 0.027), frequency of 44.2% (P < 0.001), and severity of 52.6% (P < 0.001), with a complete response in 8/16 women. Side effects reported by four women who did not complete 4 weeks of the study were nausea (1/4), rash (1/4) and excessive sleepiness (3/4). Two additional patients did not provide complete data. Gabapentin is a promising new agent in the treatment of tamoxifen induced hot flashes, and should be studied further.

Effect of gabapentin on nausea induced by chemotherapy in patients with breast cancer.

In an anecdotal report, complete resolution of chemotherapy-induced nausea was seen in a patient with breast cancer, after she was placed on the anticonvulsant gabapentin. On this basis, we did an open-label study in which oral gabapentin 300 mg thrice daily was given for every other chemotherapy treatment in nine patients with breast cancer. Six of the nine reported at least a three-point improvement in peak delayed nausea (on an eight-point nausea scale), and three patients had complete resolution of nausea when taking gabapentin. This preliminary evidence shows that gabapentin might have a role in treatment of chemotherapy-induced nausea.