Prolactin Response to Metformin in Cabergoline-Resistant Prolactinomas: A Pilot Study.

INTRODUCTION: Cabergoline is the treatment of choice for prolactinomas. However, 10-20% of prolactinomas are resistant to cabergoline. Metformin, a biguanide widely used in the treatment of diabetes mellitus, has been shown to reduce prolactin secretion in various pituitary tumor-cell lineages both in vitro and in vivo and in human pituitary adenomas in vitro. The aim of this study is to test the effects of metformin addition to cabergoline treatment on prolactin levels in patients with resistant prolactinomas. SUBJECTS AND METHODS: This is a prospective study performed in an outpatient clinic in a reference center. Ten adult patients (26-61 years) with prolactinomas (7 M), persistent hyperprolactinemia (38-386 ng/mL) under cabergoline treatment (2-7 mg/week) for at least 6 months (6-108 months), features of metabolic syndrome, and not taking metformin were included. Metformin (1.0-2.5 g v.o./day) was given according to patients' tolerance. Cabergoline doses were kept unchanged. Serum prolactin levels were measured before and after short- (30-60 days) and long-term (120-180 days) metformin treatment. RESULTS: Mean prolactin levels did not show any significant changes (148 ± 39 vs. 138 ± 42 vs. 133 ± 39 ng/mL, before, at 30-60 days, and at 120-180 days, respectively, p = 0.196) after metformin (mean dose: 1.25 g/day; range: 1.0-2.0 g/day). No patient reached a normal prolactin level during metformin treatment. Two patients were considered partial responders for exhibiting prolactin decreases ≥50% at a single time point during metformin. CONCLUSION: Metformin addition to ongoing high-dose cabergoline treatment in patients with cabergoline-resistant prolactinomas failed to show a consistent inhibitory effect in serum prolactin levels.

Treatment of subcutaneous nodules after infusion of apomorphine; a biopsy-controlled study comparing 4 frequently used therapies.

This study aimed to provide clinical evidence for existing treatments of subcutaneous nodules after subcutaneous infusion of apomorphine, using a biopsy-controlled prospective crossover design of four treatments. We demonstrated that dilution of apomorphine significantly improved patient satisfaction, while subcutaneous hydrocortisone reduced nodule size, however with no differences in the histopathology.

High dose antipsychotic polypharmacy and dopamine partial agonists - time to rethink guidelines?

Guidelines for the treatment of schizophrenia limit the use of antipsychotic agents to clinically-established maximum doses. This acknowledges both the absence of additional efficacy of dopamine D2 receptor antagonists above a receptor occupancy threshold, and the increases in side effects that can occur at higher doses. These limits restrict the dosing of combinations of antipsychotics as they do single agents; drugs sharing the major antipsychotic mechanism of D2 receptor antagonism will act additively in blocking these receptors.Several newer antipsychotic drugs, including aripiprazole and cariprazine, act as partial agonists at the D2 receptor site and avoid action at several other receptors, effects at which are responsible for some non-dopaminergic adverse effects. This pharmacology imparts different characteristics to the drugs resulting often in a more favourable side effect profile. Their partial agonism, along with high affinities for the D2 receptor, also means that these drugs given adjunctively may in part replace, rather than enhance, the D2 antagonism of other antipsychotic agents. This can result in an improvement in certain side effects without loss of antipsychotic efficacy.This article makes the case for distinguishing the D2 partial agonists from antagonists in defining maximum doses of combined treatments, which would increase the options available to the prescriber, emphasising that pharmacological mechanisms need to be understood in identifying optimal treatments for psychotic illness.

Lipopolysaccharide/D-galactosamine-induced acute liver injury could be attenuated by dopamine receptor agonist rotigotine via regulating NF-κB signaling pathway.

The pathological of lipopolysaccharide (LPS)/D-galactosamine (D-Gal)-induced acute liver injury is similar to what is seen clinically, and be mediated by the release of pro-inflammatory mediators. A growing body of studies have shown that dopamine (DA) and DA receptor agonist are associated with inflammation and immune response. Rotigotine, a non-ergoline dopamine receptor agonist, is a drug for the treatment of Parkinson's disease. Rotigotine-loaded microspheres (RoMS) is an intramuscular extended-release agent, which can steadily release rotigotine for more than 7 days after a single administration. The present study aimed to investigate the effects of rotigotine and RoMS on inflammation and acute liver injury induced by LPS/D-Gal in mice. The LPS/D-Gal-induced liver injury was evidenced by increases of serum aminotransferases activities and liver histological lesions. Pretreatment with rotigotine or RoMS not only ameliorated the liver histologic lesions, but also reduced the activities of serum aminotransferases and the production of TNF-α. It also showed that rotigotine and RoMS increased DA receptor 2 (DRD2) expression in LPS/D-Gal-exposed mice. Rotigotine and RoMS activated ß-arrestin 2, inhibited the phosphorylation of Akt, IκB and the transposition of NF-κB. In line with the above findings, the protective effects of rotigotine and RoMS were abrogated by haloperidol, a DA receptor antagonist. In conclusion, dopamine receptor agonist can regulate NF-κB inflammatory signaling pathway and exert protective effects in LPS/D-Gal-induced liver injury.

First-line surgery in prolactinomas: lessons from a long-term follow-up study in a tertiary referral center.

CONTEXT: Although consensus guidelines recommend dopamine agonists (DAs) as the first-line approach in prolactinomas, some patients may opt instead for upfront surgery, with the goal of minimizing the need for continuation of DAs over the long term. While this approach can be recommended in selected patients with a microprolactinoma, the indication for upfront surgery in macroprolactinomas remains controversial, with limited long-term data in large cohorts. We aimed at elucidating whether first-line surgery is equally safe and effective for patients with micro- or macroprolactinomas not extending beyond the median carotid line (i.e., Knosp grade ≤ 1). METHODOLOGY: Retrospective study of patients with prolactinomas Knosp grade ≤ 1 treated with upfront surgery. The primary endpoint was patients' dependence on DAs at last follow-up. The secondary endpoint was postoperative complications. Independent risk factors for long-term dependence on DAs were analyzed. RESULTS: A microadenoma was noted in 45 patients (52%) and a macroadenoma in 41 (48%), with 17 (20%) harboring a Knosp grade 1 prolactinoma. Median follow-up was 80 months. First-line surgery resulted in long-term remission in 31 patients (72%) with a microprolactinoma and in 18 patients (45%) with a macroprolactinoma (p = 0.02). DA therapy was ultimately required in 11 patients (24%) with microadenomas vs. 20 (49%) with macroadenomas (p = 0.03). As for the latter, DA was required in 13 patients (76%) with Knosp grade 1 macroadenomas vs. 7 patients (29%) with Knosp grade 0 macroadenomas (p = 0.004). There was no mortality, and morbidity was minimal. Knosp grade 1 prolactinomas (OR 7.3, 95% CI 1.4-37.7, p = 0.02) but not adenoma size (i.e., macroprolactinomas) were an independent predictor of long-term dependence on DAs. CONCLUSIONS: First-line surgery in patients with microprolactinomas or macroprolactinomas Knosp grade 0 resulted in a good chance of non-dependency on DA therapy. However, in patients with prolactinomas Knosp grade 1, first-line surgery cannot be recommended, as adjuvant DA therapy after surgery is required in the majority of them over the long term.

Dopamine Prevents Ultraviolet B-induced Development and Progression of Premalignant Cutaneous Lesions through its D2 Receptors.

Although the role of dopamine (DA) in malignant tumors has been reported, its function in premalignant lesions is unknown. Herein we report that the stimulation of DA D2 receptors in endothelial cells in ultraviolet B (UVB)-induced cutaneous lesions in mice significantly reduced the tumor number, tumor burden, and malignant squamous cell carcinoma in these animals. DA D2 receptor agonist inhibited VEGFA-dependent proangiogenic genes in vitro and in vivo. However, the mice pretreated with selective DA D2 receptor antagonist inhibited the actions of the agonist, thereby suggesting that the action of DA was through its D2 receptors in the endothelial cells. To our knowledge, this study is the first to report DA-mediated regulation of pathogenesis and progression of UVB-induced premalignant skin lesions. PREVENTION RELEVANCE: This investigation demonstrates the role of dopamine and its D2 receptors in UVB induced premalignant squamous cell skin lesions and how DA through its D2 receptors inhibits the development and progression of these lesions and subsequently prevents squamous cell carcinoma of the skin.

Neonatal programming with sex hormones: Effect on expression of dopamine D1 receptor and neurotransmitters release in nucleus accumbens in adult male and female rats.

Steroid sex hormones produce physiological effects in reproductive and non-reproductive tissues, such as the brain. In the brain, sex hormones receptors are expressed in cortical, limbic and midbrain areas modulating memory, arousal, fear and motivation between other behaviors. One neurotransmitters system regulated by sex hormones is dopamine (DA), where during adulthood, sex hormones promote neurophysiological and behavioral effects on DA systems such as tuberoinfundibular (prolactin secretion), nigrostriatal (motor circuit regulation) and mesocorticolimbic (driving of motivated behavior). However, the long-term effects induced by neonatal exposure to sex hormones on DA release induced by D1 receptor activation and its expression in nucleus accumbens (NAcc) have not been fully studied. To answer this question, neurochemical, cellular and molecular techniques were used. The data show sex differences in NAcc DA extracellular levels induced by D1 receptor activation and protein content of this receptor in male and female control rats. In addition, neonatal programming with a single dose of TP increases the NAcc protein content of D1 receptors of adult male and female rats. Our results show new evidence related with sex differences that could explain the dependence to drug of abuse in males and females, which may be associated with increased reinforcing effects of drugs of abuse.

The effects of a novel inhibitor of tumor necrosis factor (TNF) alpha on prepulse inhibition and microglial activation in two distinct rodent models of schizophrenia.

Increased neuroinflammation has been shown in individuals diagnosed with schizophrenia (SCHZ). This study evaluated a novel immune modulator (PD2024) that targets the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) to alleviate sensorimotor gating deficits and microglial activation employing two different rodent models of SCHZ. In Experiment 1, rats were neonatally treated with saline or the dopamine D2-like agonist quinpirole (NQ; 1 mg/kg) from postnatal day (P) 1-21 which produces increases of dopamine D2 receptor sensitivity throughout the animal's lifetime. In Experiment 2, rats were neonatally treated with saline or the immune system stimulant polyinosinic:polycytidylic acid (Poly I:C) from P5-7. Neonatal Poly I:C treatment mimics immune system activation associated with SCHZ. In both experiments, rats were raised to P30 and administered a control diet or a novel TNFα inhibitor PD2024 (10 mg/kg) in the diet from P30 until P67. At P45-46 and from P60-67, animals were behaviorally tested on auditory sensorimotor gating as measured through prepulse inhibition (PPI). NQ or Poly I:C treatment resulted in PPI deficits, and PD2024 treatment alleviated PPI deficits in both models. Results also revealed that increased hippocampal and prefrontal cortex microglial activation produced by neonatal Poly I:C was significantly reduced to control levels by PD2024. In addition, a separate group of animals neonatally treated with saline or Poly I:C from P5-7 demonstrated increased TNFα protein levels in the hippocampus but not prefrontal cortex, verifying increased TNFα in the brain produced by Poly I:C. Results from this study suggests that that brain TNFα is a viable pharmacological target to treat the neuroinflammation known to be associated with SCHZ.

Outcomes of Transsphenoidal Microsurgery for Prolactinomas - A Contemporary Series of 162 Cases.

INTRODUCTION: Renewed interest in transsphenoidal surgery (TSS) as a therapeutic option for prolactinomas has emerged. This study is aimed at defining the current role of pituitary surgery in the management of prolactinomas. MATERIALS AND METHODS: In this retrospective, consecutive single-center study, 162 patients who underwent primary microscopic TSS for prolactinomas between 2006 and 2019 were analyzed regarding surgical indication, previous dopamine-agonist (DA) treatment, early remission rates (3 months postoperatively), surgical complications and pituitary function. RESULTS: Seventy-four microprolactinomas and 88 macroprolactinomas were operated by TSS. 62.3% of the patients had received prior DA treatment. For microprolactinomas, the predominant indication for surgery was patient's wish (41.9%), while indications for macroprolactinomas varied. For enclosed microprolactinomas, the initial remission rate was 92.1%, while for macroprolactinomas, the rate was 70.4%. No significant difference of remission rates was found between DA-pretreated (65.3%) and non-pretreated (72.1%) patients (p=0.373).None of the patients suffered a significant complication. Re-operation for a postoperative cerebrospinal fluid leak was required in one patient (0.6%). Permanent postoperative deterioration of pituitary function was only observed in one of 158 patients with surgery for a prolactinoma (0.6%). Improvement of pituitary function was observed in 8 of 25 patients (32%) with preoperative deficits. CONCLUSION: Transsphenoidal microsurgery is safe and efficient for treatment of prolactinomas. It is particularly suitable for enclosed prolactinomas. The patient should be well informed of the pros and cons of the treatment options, which include DA medication and TSS, and the patient's preference should be taken into account during decision-making.

Intermittent dietary supplementation with fish oil prevents high fat diet-induced enhanced sensitivity to dopaminergic drugs.

Eating a high fat diet can lead to obesity, type 2 diabetes, and dopamine system dysfunction. For example, rats eating high fat chow are more sensitive than rats eating standard chow to the behavioral effects (e.g., locomotion and yawning) of dopaminergic drugs (e.g., quinpirole and cocaine). Daily dietary supplementation with 20% (w/w) fish oil prevents high fat diet-induced enhanced sensitivity to quinpirole-induced yawning and cocaine-induced locomotion; however, doctors recommend that patients take fish oil just two to three times a week. To test the hypothesis that intermittent (i.e., 2 days per week) dietary supplementation with fish oil prevents high fat diet-induced enhanced sensitivity to quinpirole and cocaine, rats eating standard chow (17% kcal from fat), high fat chow (60% kcal from fat), and rats eating standard or high fat chow with 20% (w/w) intermittent (e.g., 2 days per week) dietary fish oil supplementation were tested once weekly with quinpirole [0.0032-0.32 mg/kg, intraperitoneally (i.p.)] or cocaine (1.0-17.8 mg/kg, i.p.) using a cumulative dosing procedure. Consistent with previous reports, eating high fat chow enhanced sensitivity of rats to the behavioral effects of quinpirole and cocaine. Intermittent dietary supplementation of fish oil prevented high fat chow-induced enhanced sensitivity to dopaminergic drugs in male and female rats. Future experiments will focus on understanding the mechanism(s) by which fish oil produces these beneficial effects.

Increased prevalence of impulse control disorder symptoms in endocrine diseases treated with dopamine agonists: a cross-sectional study.

INTRODUCTION: Impulse control disorders (ICDs) have been described as a side effect of dopamine agonists (DAs) in neurological as well as endocrine conditions. Few studies have evaluated the neuropsychological effect of DAs in hyperprolactinemic patients, and these have reported a relationship between DAs and ICDs. Our objective was to screen for ICD symptoms in individuals with DA-treated endocrine conditions. MATERIALS AND METHODS: A cross-sectional analysis was conducted on 132 patients with pituitary disorders treated with DAs (DA exposed), as well as 58 patients with pituitary disorders and no history of DA exposure (non-DA exposed). Participants responded to the full version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's disease (QUIP). RESULTS: Compared with the non-DA-exposed group, a higher prevalence of DA-exposed patients tested positive for symptoms of any ICD or related behavior (52% vs. 31%, p < 0.01), any ICD (46% vs. 24%, p < 0.01), any related behavior (31% vs. 17%, p < 0.05), compulsive sexual behavior (27% vs. 14%, p < 0.04), and punding (20% vs. 7%, p < 0.02) by QUIP. On univariate analysis, DA treatment was associated with a two- to threefold increased risk of any ICD or related behavior [odds ratio (OR) 2.43] and any ICD (OR 2.70). In a multivariate analysis, independent risk factors for any ICD or related behavior were DA use (adjusted OR 2.22) and age (adjusted OR 6.76). Male gender was predictive of the risk of hypersexuality (adjusted OR 3.82). DISCUSSION: Despite the QUIP limitations, a clear sign of increased risk of ICDs emerges in individuals with DA-treated pituitary disorders. Our data contribute to the growing evidence of DA-induced ICDs in endocrine conditions.

Medical Therapy of Acromegaly in Germany 2019 - Data from the German Acromegaly Registry.

CONTEXT: Acromegaly is a rare disease caused by excessive growth hormone (GH) secretion from pituitary adenomas in most cases. If neurosurgical therapy is contraindicated or not sufficient, medical therapy is the second line therapy. OBJECTIVE: To describe current medical therapy in acromegaly. DESIGN & METHODS: Retrospective data analysis from 2732 patients treated in 69 centers of the German Acromegaly Registry. 749 patients were seen within the recent 18 months, of which 420 were on medical therapy (56.1%). RESULTS: 73% of medically treated acromegalic patients had normal/low IGF-1 levels. 57% of patients with non-normalized IGF-1 levels had an IGF-1 value between 1- and 1.25-fold above the upper limit of normal. Most patients (55%) received somatostatin analogs as monotherapy, 12% GH receptor monotherapy, and 9% dopamine agonist therapy. Doses of each medical therapy varied widely, with 120 mg lanreotide LAR every 4 weeks, 30 mg octreotide LAR every 4 weeks, 140 mg pegvisomant per week and 1mg cabergoline per week being the most frequent used regimens. A combination of different medical regimens was used in almost 25% of the patients. CONCLUSION: The majority of German acromegalic patients receiving medical therapy are controlled according to normal IGF-1 levels.

Effectiveness of Cabergoline Treatment in Patients with Acromegaly Uncontrolled with SSAs: Experience of a Single Tertiary Center.

PURPOSE: To evaluate the effectiveness of cabergoline and the parameters affecting cabergoline response as add-on treatment to somatostatin analaogues (SSA) in patients with acromegaly uncontrolled with SSAs. MATERIAL AND METHOD: One hundred and twenty-nine acromegalic patients uncontrolled with SSA who had cabergoline added to their treatment were included in this retrospective study. Patients were divided into the SSAs + cabergoline-responsive (group 1) and non-responsive groups (group 2), and biochemical, pathologic, and radiologic parameters were assessed. RESULTS: IGF-1 normalization was achieved in 75 of 129 patients (58%) when cabergoline was added to the SSA treatment. Female patients were significantly higher in group 1 compared to group 2 (p=0.006). Group 1 had significantly smaller pre- and post-cabergoline tumor size (p=0.011, p=0.007 respectively), lower levels of IGF-1 in pre-and post-operative period (p=0.040, p=0.001), and lower levels of IGF-1 in pre- and post-cabergoline treatment (p<0.001). Cavernous invasion on sellar magnetic resonance imaging, dural invasion in pathologic examination were not significantly different between the groups. Sellar invasion in pathologic examination was significantly higher in group 1 (p=0.011). No significant difference was found in proliferation indices between two groups. The presence of fibrous bodies was significantly lower in group 1 (p=0.010). CONCLUSION: Cabergoline can be added to the treatment of acromegalic patients uncontrolled with SSAs due to its ease of use and low economic cost, especially in patients with acromegaly who have small adenomas and no fibrous bodies.

A 12-month, dose-level blinded safety and efficacy study of levodopa inhalation powder (CVT-301, Inbrija) in patients with Parkinson's disease.

INTRODUCTION: CVT-301 (Inbrija®) is a levodopa inhalation powder for on-demand treatment of OFF episodes in Parkinson's disease patients treated with carbidopa/levodopa. Safety and efficacy results of a 12-month, dose-level blinded extension study of a phase 3 trial (SPAN℠-PD) of CVT-301 are presented. METHODS: Patients were receiving oral carbidopa/levodopa and adjunctive CVT-301 treatment, blinded to dose (60 mg or 84 mg, N = 325). Study visits occurred every 3 months. Pulmonary function was assessed by spirometry. Other safety assessments included dyskinesia and adverse events (AEs). Secondary objectives of the study included maintenance of improvement assessments for occurrence of an ON state during the 60-min post-dose period, change in total daily OFF time, and Patient Global Impression of Change (PGIC). RESULTS: Most frequent AEs (≥5%) were cough (15.4%), fall (13.1%), upper respiratory tract infection (7.1%), and dyskinesia (5.1%). Severe AEs (>1 event) were cough (1.9%) and dyskinesia (0.6%). Twelve-month mean changes from baseline for FEV1, FVC, and DLCO were -0.092 L, -0.097 L, and -0.922 mL/min/mmHg, respectively. At 12 months, 73.0% of patients on 84 mg achieved an ON state within 60 min. Total daily OFF time was reduced by 0.55 h (month 1) and 0.88 h (month 12) for the 84 mg dose. Percentage of patients self-reported as improved by PGIC was 65.5-91.9% over 12 months. CONCLUSION: CVT-301 was generally well-tolerated. Twelve-month decline in pulmonary function was consistent with a prior PD control group. Exploratory efficacy results showed CVT-301 maintained improvement at achieving ON states in patients experiencing OFF episodes, decreasing daily OFF time, and maintaining improvement in PGIC.

Post-ischemic administration of dopamine D2 receptor agonist reduces cell death by activating mitochondrial pathway following ischemic stroke.

AIMS: Cerebral ischemic stroke leads to mitochondrial alterations which are key factors for initiation of various cascades resulting in neuronal damage. Dopamine D2 receptor (D2R) agonist, Sumanirole (SUM) has been reported to possess anti-inflammatory, anti-oxidant, and anti-apoptotic properties. However, the role of SUM in ischemic stroke (IS) has not been studied yet. The aim of the present study was to investigate the neuroprotective efficiency of SUM against ischemic injury and its possible effect on mitochondrial restorative mechanisms. MATERIALS AND METHODS: Transient middle cerebral artery occlusion (tMCAO) was performed in Wistar rats for 90 min occlusion and 22.5 h reperfusion to mimic ischemic stroke. Post- treatment with Sumanirole (0.1 mg/kg and 1 mg/kg; s.c.) was done at 1 h, 6 h, 12 hand 18 h after surgery. In addition, neurobehavioral analysis, mitochondrial reactive oxygen species and mitochondrial membrane potential by flow cytometric analysis, mitochondrial complexes analysis, infarct size evaluation and histological analysis were performed. KEY FINDINGS: Sumanirole restored behavioural alterations as measured by rotarod performance, grip strength, adhesive tape removal analysis and neurological deficits. In addition, it also refurbished mitochondrial dysfunction by decreasing mitochondrial reactive oxygen species production, elevating mitochondrial membrane potential and by protecting the activity of mitochondrial complexes along with histological alterations. As a result, infarct sizes were markedly reduced in tMCAO surgery animals. SIGNIFICANCE: Findings from the study provide evidence that SUM promotes neuronal survival in in vivo model of IS through mitochondria mediated neuroprotective features.

Dopamine agonists and antipsychotics.

There can potentially be a number of clinical interactions that could adversely affect patient outcomes in a patient with a prolactinoma and psychiatric disease that might require antipsychotic and dopamine agonist treatment. Dopamine agonists stimulate the dopamine D2 receptor, resulting in a decrease in prolactin (PRL) levels and in prolactinoma size but action on dopamine receptors in the meso-limbic system may rarely cause psychosis and more commonly cause impulse control disorders. The psychiatric benefits of antipsychotic agents involve blocking the D2 and other dopamine receptors but this blockade often also causes hyperprolactinemia. In patients with macroprolactinomas and psychosis, observation, estrogen/progestin replacement, and surgery can be considered in addition to dopamine agonists. In those who require dopamine agonists for PRL and tumor size control, the introduction of antipsychotics may blunt this effect, so that higher doses of the dopamine agonists may be needed. Alternatively, antipsychotics that have less of a blocking effect at the D2 receptor, such as aripiprazole, can be tried, if appropriate. For patients already on antipsychotic drugs who are found to have a macroprolactinoma for which dopamine agonists are required, dopamine agonists can be initiated at low dose and the dose escalated slowly. However, such patients require careful monitoring of psychiatric status to avoid the rare complication of exacerbation of the underlying psychosis. Again, if appropriate, use of antipsychotics that have less of a blocking effect at the D2 receptor may allow lower doses of dopamine agonists to be used in this situation.

Nose to brain delivery of rotigotine loaded chitosan nanoparticles in human SH-SY5Y neuroblastoma cells and animal model of Parkinson's disease.

Rotigotine, a non-ergoline dopamine agonist, has been shown to be highly effective for the treatment of Parkinson's disease (PD). However, despite its therapeutic potential, its' clinical applications were hindered due to low aqueous solubility, first-pass metabolism and low bioavailability. Therefore, we developed rotigotine-loaded chitosan nanoparticles (RNPs) for nose-to-brain delivery and evaluated its neuronal uptake, antioxidant and neuroprotective effects using cell-based studies. The pharmacological effects of nose-to-brain delivery of the RNPs were also evaluated in an animal model of PD. The average particle size, particle size distribution and entrapment efficiency of the RNPs were found to be satisfactory. Exposure of RNPs for 24 h did not show any cytotoxicity towards SH-SY5Y human neuroblastoma cells. Furthermore, the RNPs caused a decrease in alpha-synuclein (SNCA) and an increase in tyrosine hydroxylase (TH) expression in these cells, suggestion that the exposure alleviated some of the direct neurotoxic effects of 6-OHDA. Behavioral and biochemical testing of RNPs in haloperidol-induced PD rats showed a reversal of catalepsy, akinesia and restoration of swimming ability. A decrease in lactate dehydrogenase (LDH) and an increase in catalase activities were also observed in the brain tissues. The results from the animal model of PD show that intranasally-administered RNPs enhanced brain targeting efficiency and drug bioavailability. Thus, RNPs for nose-to-brain delivery has significant potential to be developed as a treatment approach for PD.

The D2-family receptor agonist bromocriptine but, not nicotine, reverses NMDA receptor antagonist-induced working memory deficits in the radial arm maze in mice.

Hypofunction of the NMDA receptor (NMDAr) may underlie cognitive deficits associated with schizophrenia and other psychiatric conditions including working memory (WM) impairments. Given that these deficits link closely to functional outcome, treatments remediating such deficits require identification. NMDAr hypofunction can be modeled via treatment with the antagonist MK-801. Hence, the present study determined whether cholinergic or dopaminergic agonists attenuate MK-801-induced WM deficits in mice. WM was assessed in male C57BL/6 mice trained on an automated 12-arm radial arm maze (RAM) paradigm, wherein rewards were delivered after the first but, not after subsequent entries into WM arms (8/12) and never delivered for entries into reference memory (RM) arms (4/12). Mice were then treated with MK-801 (vehicle or 0.3 mg/kg) and nicotine (vehicle, 0.03 or 0.30 mg/kg) in a cross-over design. After a 2-week washout, mice were then retested with MK-801 and the dopamine D2-family receptor agonist bromocriptine (vehicle, 3 or 10 mg/kg). In both experiments, MK-801 reduced WM span and increased RM and WM error rates. Nicotine did not attenuate these deficits. In contrast, a bromocriptine/MK-801 interaction was observed on WM error rate, where bromocriptine attenuated MK-801 induced deficits without affecting MK-801-induced RM errors. Additionally, bromocriptine produced the main effect of slowing latency to collect rewards. Hence, while NMDAr hypofunction-induced deficits in WM was unaffected by nicotine, it was remediated by treatment with the dopamine D2-family agonist bromocriptine. Future studies should determine whether selective activation of dopamine D2, D3, or D4 receptors remediate this NMDAr hypofunction-induced WM deficit.

A Real-Life Search for the Optimal Set of Conversion Factors to Levodopa-Equivalent-Dose in Parkinson's Disease Patients on Polytherapy.

BACKGROUND: A wide variety of conversion factors for a levodopa-equivalent-dose (LED) have been proposed for each Parkinson's disease (PD) medication. The currently-used set of conversion factors is based on studies that relied on subjective experience or theoretical assumptions. This set was never validated in patients receiving polytherapy. OBJECTIVES: To use real-life data to identify an optimal set of conversion factors independent of prior assumptions regarding clinical efficacy of different medications. METHODS: Retrospective analysis of data from 206 cognitively-preserved patients with advanced PD receiving polytherapy before deep brain stimulation (DBS) surgery. A nonlinear automated problem solver was used to find a set of conversion factors that, when applied, minimized the coefficient of variation of LEDs in a relatively homogenous cohort of patients. RESULTS: Independent and model-free evaluation of a wide range of possible sets of conversion factors to LED suggested a set of normalized conversion factors for immediate release levodopa (1.00), controlled release levodopa (0.88), and amantadine (1.23). A minimal clinical benefit of entacapone was observed for patients with motor fluctuations. Our analysis could not detect conversion factors for dopamine agonists and MAO-B inhibitors, possibly because their clinical contribution when added to levodopa is limited. CONCLUSIONS: Independent from previous studies and prior assumptions we show that the currently-used LED conversion factors for immediate release levodopa, controlled release levodopa and amantadine are largely correct and that dopamine agonists, MAO-B inhibitors and entacapone, given in addition to levodopa, have little additional clinical value for PD patients with motor fluctuations.

Quantitative transcranial sonography of the substantia nigra as a predictor of therapeutic response to intravenous iron therapy in restless legs syndrome.

OBJECTIVE: To analyze changes in substantia nigra (SN) iron deposits, assessed by quantitative transcranial sonography (TCS), to obtain and compare substantia nigra echogenicity indices (SNEI) at baseline and after intravenous (IV) iron therapy in patients with restless legs syndrome (RLS)/Willis-Ekbom disease (WED). METHODS: A total of 30 consecutive subjects diagnosed with RLS/WED were recruited and underwent IV iron treatment. The SNEI, total daily dose of dopamine equivalents, and International Restless Legs Syndrome Rating Scale (IRLS) scores were obtained at baseline and following IV iron administration. Comparative statistics were performed by means of nonparametric testing. RESULTS: The sample was stratified into two groups according to the median baseline SNEI and the grade of SN hypoechogenicity: severely hypoechogenic (HE) (n = 13) and moderately HE (n = 17). Following IV iron, the increase in SNEI among severely HE subjects was 19% (0.038 ± 0.046 cm2; P < 0.01), whereas in moderately HE subjects it was 10% (0.021 ± 0.069 cm2; P = 0.28). Among severely HE subjects, the average reduction in IRLS following IV iron was 10 ± 7.12 points (P < 0.01), in contrast to 1.85 ± 9.85 (not significant) among moderately HE subjects. Finally, we quantified the percentage of patients in each group who were able to reduce by ≥30% their total daily dopaminergic requirements (TDR) after IV iron, with a 57.14% reduction in the severely HE group vs 25% in the moderately HE group (P = 0.1). Three of 30 subjects (17%) were able to completely cease all dopaminergic treatment. CONCLUSION: Intravenous iron caused changes in SNEI in both groups of patients, reflecting an increase in brain iron stores. However, the increase in SNEI was greater in patients previously defined as severely HE. Furthermore, RLS/WED symptoms also improved more in severely HE subjects, and there was a greater reduction in TDR. This study highlights the role of TCS in quantifying brain iron deposits and in predicting which patients will likely benefit from IV iron.