Browsing by study line "Pharmacology"

Amyotrophic lateral sclerosis (ALS) is a rare fatal neurodegenerative disease in which both the upper and lower motor neurons degenerate. Pathological features of the disease include misfolded proteins and accumulations in the central nervous system. The molecular mechanisms of the disease include neuroinflammation, glutamate induced excitotoxicity, and endoplasmic reticulum stress (ER-stress). Numerous genetic defects have been identified in the background of ALS, the most common mutations are in the C9ORF72, SOD1, TDP43 and FUS genes. For each gene mutation, it is important to develop a reliable animal model of ALS for studying pathology and testing new therapies. The most common and most recently found gene mutation, the C9ORF72 repeat expansion mutation, does not yet have an established animal disesase model. The molecular mechanisms of the disease include neuroinflammation, glutamate induced excitotoxicity, and endoplasmic reticulum stress (ER- stress). There is no drug treatment to cure or slow ALS, so the need for new drug therapies that affect the course of the disease is significant. Cerebral dopamine neurotrophic factor (CDNF) protects and restores dopamine neurons and controls ER-stress in preclinical models of Parkinson’s disease. CDNF has also been shown to improve motor coordination as well as protect spinal cord neurons from cell destruction in ALS genetic SOD1- G93A mouse and TDP-43M337 animal models. The purpose of this master's thesis study was to characterize the changes related to neurodegeneration and neuroinflammation in the new C9ORF72-500 disease model and study ER stress of the SOD1-93A disease model and the effect of CDNF on ER stress in SOD1-model and on inflammation in C9-model. In the first sub-study, brain sections from C9ORF72 transgenic and wild-type mice at different time points were subjected to six different immunohistological stainings. The results were compared at each time point (30, 70 and 170) between the wild type and the transgenic group. In another sub-study, spinal cord sections from CDNF snd vehicle treated SOD1- G93A mice were subjected to immunofluorescence staining, after which the intensity of their ER stress marker, GRP78, was analyzed using a confocal microscope. GFAP stained brain sections from CDNF and vehicle treated C9ORF72 mice were analyzed using microscope and imaging analyses. The results of the first sub-study showed neuroinflammation at 24 weeks timepoint in the transgenic group compared to wild-type mice. Pathological features of C9-ALS, various protein accumulations, were observed only in the transgenic group, mainly at 24 weeks. No neuronal loss was observed in this study. The obtained results support the previously published research results and support the reliability of the studied disease model. In the second sub-study ER stress levels were higher in SOD1-mice compared to wild-type mice. Single intracerebroventrical CDNF injection reduced ER stress in SOD1-G93A transgenic mice almost to the same level as ER stress in wild-type mice. CDNF treatment also showed a tendency for reducing inflammation in hippocampus and motor cortex of C9ORF72 mice. The results confirm the pathological role of ER stress in ALS and show that CDNF reduces ER stress when administered as early in the disease as possible, when neuronal damage begins to occur but does not yet lead to neuronal destruction. CDNF appears to be a promising drug candidate for the treatment of ALS and should therefore be further investigated.

Introduction: When people age, the composition of sleep changes and sleep becomes more sensitive to external disturbances, making insomnia also more common. Medication is not the first-line treatment option for insomnia. Benzodiazepines or benzodiazepine receptor agonists for the treatment of insomnia have been in the focus of past studies. The content of the dosing instructions for the supplied medicines has not been studied. The dosing instructions should provide clear instructions on how to dose the medicine prescribed to the patient. The aim of this study was to investigate the content and quality of dosing instructions prescribed for the treatment of insomnia for Finns aged ≥75 years in 2020 based on the prospective reimbursement register data by the Social Insurance Institution of Finland (Kela). Materials and methods: The reimbursed purchases of all medicines by persons aged ≥75 years from 1.1.2020 to 31.12.2020 were selected by ATC code from the medicines data according to the Insomnia: Current Care guidelines. The data was gathered from Kela’s dispensations reimbursed under the National Health Insurance scheme. The dataset consisted of 1,080,843 delivery lines, which were screened, and 328,285 lines were included in the analyses. Dosage instructions were reviewed according to the following predetermined five categories: frequency of use, dose, timing, warnings or remarks, and inappropriate instructions. In addition, 1000 dosing instructions were randomly derived to study the phrasing and appropriateness of the dosing instructions in more detail. Results: In 2020, an average of 3.8 reimbursed hypnotic drug deliveries were made per elderly person. Of the deliveries, 68% were for women. 52% of drug deliveries were partially made later and not by original prescription. In the hypnotic dataset, the three most administered drugs were zopiclone (41%), mirtazapine (34%) and zolpidem (12%). The dosage was prescribed in 98–99% of the dosage instructions. Dosing schedule was reported in 83% of dosing instructions and regularity of use was reported in 57% of them. Only 3-6% of the dosing instructions had comments or warnings. 1–2% of the dosing instructions were vague. The duration or regularity of use was clearly indicated in 5% of the dosing instructions. Only 0.1% of dosage instructions contained instructions for discontinuation or reduction. Discussion: The dose and timing of administration were well reported, but the frequency of use was reported in only about half of the dosing instructions. Only few dosing instructions contained remarks or warnings even though hypnotics are at risk for the elderly. Among the three most administered drugs for the treatment of insomnia were two benzodiazepine receptor agonists, zopiclone and zolpidem. However, they may not be suitable for the elderly according to Beers criteria and their use should be avoided. During 2020, an average of four drug deliveries were made per elderly person for the treatment of insomnia, which may indicate prolonged hypnotics use. In addition, more than half of the deliveries were partially made later and not by original prescription. Thus, several drug packages are prescribed for prescriptions, although the drug-based treatment of insomnia should only be short-lived. Conclusions: There are significant deficiencies in the contents and quality in the dosing instructions for drugs delivered to the elderly for insomnia. Minimum information on dose, timing and duration of use was not found in all dosing instructions in this study. Understandable dosing instructions and the reduction in the amount of medication in the prescription could have a further effect on reducing the long-term use of hypnotics, also increasing the safety of medicine use in the elderly.

Binge eating disorder (BED) is the most common eating disorder characterized by compulsive recurrent binge eating episodes with the sense of a lack of control. During a binge eating episode, one eats a larger amount of food, typically high in fat and/or sugar, than would normally be eaten in a discrete period of time. After the episode, negative emotions, such as shame and self-disgust, are present. However, BED does not include compensatory behavior, such as vomiting or excessive exercise. Due to compulsive and uncontrollable eating behavior, it has been suggested that BED represents a food addiction. Eating energy-dense food activates the dopamine, opioid, and endocannabinoid systems in the brain. This elicits the activation of the reward process. Some drugs and medications affect the same neurotransmitter systems, which may produce neuronal alterations in the reward process, leading to an addiction. Several studies have found that cannabidiol (CBD) reduces the self- administration of cocaine, morphine, alcohol, and sucrose in rodents, suggesting an effect on the reward-response. Some of these effects have been shown to be mediated by cannabinoid receptor 2 and TRPV1 receptor. However, the effects of CBD on bingeing behavior have not been studied up to date. The aim of the study was to investigate the effect of CBD on homeostatic feeding and binge eating behavior in C57BL/6 mice. Five separate experiments were conducted. The first experiment investigated the effect of CBD (15, 50, and 150 mg/kg, i.p.) on locomotor activity in a modified open field test over a 2-hour period. In the second test, the effect of CBD (15, 50, and 150 mg/kg, i.p.) on homeostatic feeding was monitored in non-bingeing mice. Next, a limited intermittent access binge eating model without food deprivation or stressors was inducted. Mice had access to laboratory chow ad libitum, but a high energy diet (high in fat, HED) was presented in 24-hour periods every 5-8 days. Then the effect of CBD (15, 50, and 150 mg/kg, i.p.) on HED and chow intake in bingeing mice was investigated. In the fourth experiment, seven days following the administration, the after effect of CBD was studied by monitoring food intake without CBD treatment. Finally, it was investigated whether the effect of CBD can be inhibited by TRPV1 receptor antagonist AMG9810 (1 mg/kg, i.p). In each test, the food intake was monitored at the time point 0,5, 2,5, and 24 h after CBD treatment. Also, water consumption was measured in each experiment. The results revealed that CBD does not affect locomotor activity or homeostatic feeding at a dose of 15, 50, or 150 mg/kg (i.p). However, the results showed that CBD reduces the intake of HED in a dose-dependent manner (15, 50, or 150 mg/kg; i.p.) and, possibly, increases chow intake. No after effect was observed seven days following the administration. Most likely, TRPV1 does not mediate the effect of CBD on HED intake. Furthermore, no significant effects on water intake were observed. In this study, the core aims were to evaluate whether CBD affects homeostatic feeding or binge eating behavior in mice. The results provided a novel insight into the effects of CBD. The findings indicate that the acute systemic administration of CBD reduces HED intake, and possibly, simultaneously increases chow intake, suggesting a balancing effect on feeding in bingeing mice. However, the role of TRPV1 in this effect remains unclear, and further studies are needed.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder caused by degeneration of motor neurons in brain and spinal cord. The degeneration of motor neurons leads to muscle atrophy and paralysis. Currently there is no cure for ALS. Available drugs for ALS can lengthen the survival time by a couple of months. Several factors involve the pathophysiology of ALS, such as endoplasmic reticulum stress and neuroinflammation. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a protein which has shown neuroprotective effects on animal models of Parkinson disease and brain ischemia. C-terminal fragment of MANF can cross the blood-brain barrier, allowing it to be administered subcutaneously instead of injected directly into the brain. The experimental part consists of two parts. The aim of the first part was to study the pharmacokinetic properties of next generation MANF (C-MANF). The aim of the second part was to elucidate the effect of twice a week administered subcutaneous injection of C-MANF in genetic SOD1-G93A mouse model and its neuroprotective effects by assessing protection of lumbar motor neurons. Pharmacokinetic properties of C-MANF were determined in wild type mice after a single subcutaneous injection of C-MANF at different time points by using indirect ELISA assay. The effects of C-MANF in SOD1-G93A mouse model were assessed by subcutaneous injection of either C-MANF or PBS twice a week and by monitoring clinical score and motor behavior of mice from 10 weeks of age to clinical endpoint. Hematoxylin eosin staining was used to study neuroprotective effects of C-MANF. C-MANF administered subcutaneously is absorbed into the blood circulation and the highest serum concentration of C-MANF is after 60 minutes of dosing. Subcutaneously injected C-MANF also crosses the blood-brain barrier and reach the brain in 120 minutes. C-MANF did not preserve motor function or ameliorated ALS symptoms in SOD1-G93A mouse model. In this study C-MANF did not increase the survival of SOD1-G93A mice. C-MANF did not significantly protect motor neurons from degeneration even though there was a slight trend between the groups. No beneficial effects were observed with C-MANF in SOD1-G93A mouse model and therefore the dose and frequency of administration of C-MANF were not optimal. Subcutaneously injected C-MANF provides a safer dosing option for neurodegenerative disorders.

The most typical symptoms of dementia include impairment of cognitive brain functions, such as memory and thinking. Most common forms of dementia include Alzheimer's disease, vascular dementia, Lewy body dementia, and frontotemporal dementia, which is caused by degeneration of the frontotemporal lobe. Alzheimer's disease is the most common form of dementia, covering about 75% of all the cases. The pathophysiology of Alzheimer's disease includes beta-amyloid plaques and tau proteins, which accumulate in the brain, and which have been linked to damage to nerve pathways and the appearance of the typical symptoms of the disease. The disorder is progressive, but the exact cause remains unknown. However, old age (>65 years), the APOE-4 gene, lifestyle, and some comorbidities, such as cardiovascular diseases, are considered risk factors. Even though extensive research has been conducted, there is currently no curative treatment for Alzheimer's disease. Sleep disorders can be both a symptom of Alzheimer's disease and a risk factor for the onset of the disorder. Therefore, the mechanisms of sleep and circadian rhythm are connected to the pathophysiology of Alzheimer's disease, for example through the glymphatic system that cleans the brain mainly during deep sleep. Many drugs for Alzheimer's disease have a recommended time of administration. The dosing time can be very important issue in terms of the effectiveness of the drug. According to a recent study, sleep and circadian rhythm have not been considered in most studies on new rapid-acting antidepressants. Therefore, we carried out an analogous systematic literature review for Alzheimer's disease and dementia. The aim of this study was to find out whether sleep and circadian rhythm have been considered in the most cited preclinical and clinical drug research articles for Alzheimer's disease and dementia during the last decade (2010–2020). In addition, it was examined which drug groups the studied compounds belonged to, and what was the sex distribution of the test subjects in the studies. The number of subjects was also determined from clinical studies, and the animal species from preclinical studies. The research articles analysed in the study were collected with a systematic literature review of Scopus database. The study found that most studies did not include any consideration of sleep or circadian rhythm. Most of the investigated compounds were small molecules, followed by supplements and herbs, and rest classified as biological drugs. Most of the clinical trials were relatively small studies with less than a hundred subjects or hundreds of subjects. Among the 100 most cited clinical research articles, there were 14 reanalyses and observational studies that were not included in this analysis of subject numbers. In clinical studies, most of the test subjects were usually female, while preclinical studies used commonly male animals. To conduct more open and reliable science in the future, drug research should pay more attention to the subjects’ sleep patterns, the time of drug administration, and reporting on these issues in the articles, which is usually part of the requirements of scientific journals. This could potentially narrow the translational gap between preclinical and clinical research.

Parkinson’s disease (PD) is a neurodegenerative disease in which dopaminergic neurons that form the nigrostriatal pathway gradually die. This causes the main motor symptoms of Parkinson’s disease: tremor, rigidity and bradykinesia. While PD affects 1-2% of total population, all currently used medicines are symptomatic, and there is no disease modifying therapy available at present. Although several different animal models for Parkinson’s disease exist, the lack of adequate animal models is often cited as a major obstacle for predicting the clinical success of potential drug candidates. Lewy bodies (LBs) are abnormal aggregates that develop and spread inside nerve cells of human PD patients, their main structural component being α-synuclein. Because α-synuclein is thought to play a major role in the pathology of PD, much research has been focused on it. Different α-synuclein-based animal models of PD exist today, of which the most recent are based on using direct injections of preformed α-synuclein fibrils (PFFs). These new α-synuclein based disease models have helped to understand the disease process in PD better, but cell death in these models takes longer to achieve and is often less pronounced compared to traditional neurotoxin based animal models of PD. The aim of this study was to participate in the development and characterization of a novel mouse model of PD. This new model combines PFF-injections with the commonly used neurotoxin 6-OHDA, which should result in more robust dopamine pathway degeneration than what is seen with the current PFF-based models. The main hypothesis of this study was that the combination of intrastriatal injections of PFFs and a low dose of 6-OHDA would cause gradual spreading of the α-synuclein aggregation pathology in the nigrostriatal dopamine pathway and progressive dopamine neuron loss leading to motor deficits. C57BL/6 mice were stereotactically injected unilaterally with both PFF and 6-OHDA, and their performance was assessed every other week with different behavioral tests until week 12. At the end, brains were collected and optical density of tyrosine hydroxylase (TH) and dopamine transporter (DAT) was measured from striatal sections, and TH and DAT positive cells in the substantia nigra were counted. The amount of Lewy bodies present in the brain slices was also counted from the cortex and substantia nigra areas of the brain. In the histological assays, statistically significant reductions of both TH and DAT were found in the brain sections of the PFF + 6-OHDA combination group and the amount of TH and DAT positive cells were lower in this group compared to the group receiving vehicle treatment only. However, the results of behavioral tests were non-significant, although a non-statistical positive trend in the amphethamine-induced rotations test was observed where mice receiving PFF + 6-OHDA rotated the most. Taken together, combination model that utilizes both PFF and 6-OHDA injections seems like a promising candidate in modelling PD in mice, but much more research and further development of the model is required before this combination model is ready and robust for use in drug development.

Cytochrome P450 (CYP) enzyme inhibition is one of the most common reasons for adverse drug-drug interactions. An especially harmful form of inhibition is time-dependent inhibition (TDI) in which the inhibition potency increases over time and persists even after discontinuation of the drug. Both direct and time-dependent inhibition can be efficiently screened with the so-called cocktail method containing several CYP-selective probe substrates in a single reaction mixture. This method is practical especially in ADME studies of drug development, as it offers lower costs, consumption of fewer reagents and faster implementation in comparison to conventional methods. In addition, the cocktail method can be used to establish new diagnostic CYP inhibitors in vitro. The aim of this Master’s thesis was to participate in the development and optimization of a new cocktail assay method. The method was developed for screening of major drug-metabolizing CYP enzymes in vitro both in a direct and time-dependent manner using pooled human liver microsomes. Based on preliminary testing, included probe substrates were divided into two cocktails to avoid significant inter-substrate interactions: cocktail I containing tacrine/CYP1A2, bupropion/CYP2B6, amodiaquine/CYP2C8, tolbutamide/CYP2C9 and midazolam/CYP3A4, and cocktail II containing coumarin/CYP2A6, (S)-mephenytoin/CYP2C19, dextromethorphan/CYP2D6 and astemizole/CYP2J2. First, cocktail incubation conditions were optimized, followed by the determination of probe reaction kinetics, kinetic parameters (Km, Vmax) and inter-substrate interactions with single- or dual-substrate incubations. Finally, suitable probe substrate concentrations and the composition of cocktails was evaluated based on the obtained results. As a result of assay optimization, optimal incubation conditions for yet unoptimized cocktail II were established. In optimized incubation conditions, all probe reactions exhibited saturable Michaelis-Menten kinetics except for tacrine 1-hydroxylation (CYP1A2), which exhibited biphasic kinetics instead (Km1: 7.36, Km2: 517). The selected probe substrate concentrations were all below or near their respective Km values except for (S)-mephenytoin 4’-hydroxylation (40 µM vs. Km of 12.5 µM); however, its concentration could not be reduced in order to maintain sufficient metabolite formation for UHPLC-MS/MS-analysis. Dual-substrate incubation assays demonstrated a need for the reduction of bupropion concentration below 100 µM due to its inhibitory effects on CYP2C8 and CYP3A4. In addition, chlorzoxazone/CYP2E1 and testosterone/CYP3A4 were tested as complementary probe substrates for the cocktails; however, they proved to be unsuitable for both cocktails due to significant interactions (>40% inhibition). Prior to the deployment of the method, some adjustments of probe substrate concentrations are still required in addition to consideration of the suitability of less commonly used CYP3A4 and CYP2E1 probe reactions to improve cocktail coverage. Lastly, validation of the method with known time-dependent model inhibitors should also be conducted. Besides to improvement of the cocktails, new information was generated on inter-cocktail probe-probe interactions and enzyme kinetics of probe reactions, especially for the less-studied astemizole O-demethylation (CYP2J2) and tacrine 1-hydroxylation (CYP1A2). Generated information can be used, for example, in the development of new cocktails.

Dilated cardiomyopathy is a non-ischemic cardiac disorder predisposing to heart failure, and the characteristics of dilated cardiomyopathy emerge under normal loading conditions. Dilated cardiomyopathy can be consequence of various conditions e.g. genetic mutations, virus infection or toxin exposures. One of the significant causes of familial dilated cardiomyopathy in Finland is mutation S143P in LMNA-gene, coding for A type lamins. Current drug therapy for dilated cardiomyopathy aims to alleviation of symptoms, prevention of complications and progression of the disease, however, efficacy of current therapy is insufficient, and novel therapy strategies are urgently required. Transcription factors are fundamental regulators of gene expression, and GATA4 is a crucial transcription factor both in embryonic and in adult heart and thus an intriguing target for therapeutic manipulation. Compounds targeting GATA4 have shown anti-hypertrophic and cardioprotective effects. Here, effects of two different hypertrophic stimuli, endothelin-1 and mechanical stretch, on human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were examined with high-content analysis and quantitative reverse transcription PCR (qRT-PCR), respectively. One hiPSC-CM line was used as a healthy control, whereas the other carried the S143P mutation in LMNA-gene (DCM-CMs). Additionally, effects of GATA4-targeting compound C-2021 on cardiomyocytes were investigated. In summary, according to proBNP staining, DCM-CMs are more hypertrophied at baseline. DCM-CMs seemed to be less susceptible to mechanical stretch-induced enhancement in BNP gene expression. In addition, compound C 2021 may have anti-hypertrophic properties suggesting it to be a potential drug candidate in cardiac diseases. Finally, lamin A seemed to mislocalize to nucleoplasm instead of nuclear lamina in DCM-CMs.

Alcohol use disorder (AUD) is a chronic relapsing brain disorder causing a high burden of disease and significant social and economic consequences to both individuals and society. Alcohol addiction, the most severe form of AUD, is characterized by compulsive seeking and use of alcohol, loss of control over limiting alcohol consumption despite negative consequences, emergence of negative emotional states, and long-lasting vulnerability to relapse related to alcohol abstinence. Powerful craving for alcohol and the chronic, relapsing nature of the disease are major problems complicating recovery from alcohol addiction and predicting poor clinical outcome. Relapse to alcohol intake can occur even after an extended period of abstinence in humans, relapse rates being highest during the first three months of alcohol withdrawal. Associative learning is a critical factor in alcohol craving when alcohol consumption is accompanied by conditioned stimulus. Cues associated with alcohol are known to induce craving and alcohol-seeking behavior increasing the risk of relapse, and this craving can be triggered by alcohol itself, alcohol-associated stimulus, or stress. Chronic alcohol exposure has been linked to changes in synaptic plasticity, neurogenesis and cell-signaling. Thus, elucidating the neural mechanisms that underlie alcohol craving and relapse would help to understand the pathology of alcohol addiction and facilitate the development of efficient treatments. In this experiment, the effects of subanesthetic-dose 10 mg/kg ketamine, an NMDAR antagonist and a major inducer of synaptic plasticity, on cue-induced alcohol-seeking behavior after withdrawal were investigated in social context in female mice. Mice were trained to voluntarily drink alcohol, and a novel methodology to study alcohol-seeking behavior after withdrawal allowed to perform the experiment with a minimum of human interference in totally automated social home cage environment. The analyses of behavioral data showed that pairing sweetened alcohol with conditioned stimulus resulted in cue-induced alcohol-seeking behavior, and no differences in alcohol conditioning were observed between treatment groups. However, the behavioral activity in extinction tests after withdrawal showed that alcohol-seeking behavior was not altered by ketamine treatments. In biochemical analyses, the effects of subanesthetic-dose ketamine on ΔFosB and BDNF protein levels in the brain areas important for alcohol addiction were studied. ΔFosB expression levels in the mouse nucleus accumbens were analyzed with western blot and BDNF protein levels in the mouse prefrontal cortex were determined using enzyme-linked immunosorbent assay (ELISA). The results from biochemical analyses showed that levels of ΔFosB and BDNF were unaltered by ketamine treatments. Anyhow, the experiment provided important insights into the interactions of ketamine and alcohol craving and relapse, a topic that has been insufficiently studied in novel preclinical models.

Parkinson’s disease (PD) is a progressive chronic neurodegenerative disorder, which results in the selective loss of dopaminergic neurons in the substantia nigra (SN). The loss of these neurons results in the dysfunction of the nigrostriatal pathway bringing forth the characteristic motor symptoms seen in PD: postural instability, rigidity, slowness of movement and resting tremors. Non-motor symptoms, such as cognitive deficits, depression and impaired olfaction, typically emerge before motor symptoms. Currently available treatments only provide symptomatic relief with diminishing returns over time and no improvements on the overall outcome of the disease. Neurotrophic factors (NTF) have been of particular interest as a possible curative treatment for PD due to their potential for neuroprotection and neurorestoration. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an NTF that has shown promising results in numerous in vitro and in vivo studies of PD. However, therapy with MANF and other NTFs involves surgical intervention for local administration, as NTFs cannot cross the blood-brain barrier (BBB). Therefore, the therapeutic potential of a systemically administered NTF would be tremendous, as it would lead to a significantly more favorable risk-benefit ratio for the patient. The aim of the current investigation is to evaluate the efficacy of a next generation variant of MANF in the 6-hydroxydopamine toxin-induced unilateral lesion rat model of PD. Prior in vivo results suggested that subcutaneously injected MANF variant is able to penetrate the BBB. Amphetamine-induced rotational behavior (AMPH-ROTO) was used to evaluate the severity of the unilateral lesions during the experiment every other week until the end of the experiment at week eight. Animals were divided into treatment groups during week two based on their AMPH-ROTO results. Animals received MANF variant either subcutaneously through an implanted osmotic minipump at two different dosages or as a single dose divided into three separate intrastriatal injections. Tyrosine hydroxylase (TH) immunohistochemical staining was performed on brain sections collected from the striatum and SN for data analysis. In addition to AMPH-ROTO results, the efficacy of treatment was determined via the optical density of TH-positive striatal fibers and the number of TH-positive cells in the SN. Statistically significant differences (defined by p < 0.05 and a non-zero mean difference at a 95 % confidence interval) were observed only in the number of TH-positive cells in the SN favoring intrastriatal MANF variant treatment over both intrastriatal MANF and the vehicle treatment. The main concern regarding the validity of the results was related to the heterogeneous lesion sizes in different treatment groups possibly resulting in unsuccessful randomization due to excessive baseline differences. The inadvertent negative effects of this was further exacerbated by low a priori statistical power, which in the end had likely caused inflated effect sizes. Thus, assessment of the definitions of the used statistical parameters and the limitations of the experimental design suggest that presently, the efficacy of the MANF variant could not be evaluated reliably, in spite of the statistically significant result.