Browsing by Title

Since the discovery of ketamine’s antidepressant response, numerous of studies have been observed it to alleviate depressive symptoms rapidly and effectively within hours. This is a significant advantage compared to traditional antidepressants, which take weeks to show treatment efficacy. Ketamine is a N- methyl-D-aspartate receptor (NMDA) antagonist and its underlying mechanism of is proposed to be in its ability to increase synaptic plasticity and this is ultimately believed to improve mood. On a molecular level, the antidepressant effects have been observed to be dependent on the activation of tropomyosin receptor kinase B (TrkB) signalling pathway. However, the antidepressant mechanism of ketamine remains still poorly understood as no new NMDA-antagonist or other rapid-acting antidepressants have been successfully developed for clinical use despite many years of effort. Therefore, some have proposed that the missing pieces of understanding its antidepressant effects might be linked to ketamine’s ability to modify sleep patterns and circadian-related molecules. Ketamine has especially been demonstrated to increase slow-wave activity during the following night of treatment and these changes have been shown to predict the clinical outcome in patients with major depressive disorder (MDD). Slow-wave activity is a low-frequency and high-amplitude wave seen in electroencephalography, which is highly expressed during the deepest stage of sleep, and this has been prominently found to be reduced in MDD patients. Even more intriguing, there are indications that ketamine might increase slow-wave activity also immediately after its administration. During this time, TrkB signalling is observed to became active. Following these molecular findings, we sought to investigate the link between the TrkB signalling pathway and two prominent processes occurring during slow-wave sleep. During slow-wave sleep processes such as (1) reduction of brain’s energy expenditure and (2) the activation of glymphatic system is known to occur. The glymphatic system is as lymphatic-perivascular network, which is responsible for clearing the brain from the metabolic waste. Thus, in this study, our objective was to investigate whether by causing an acute decline in adenosine-triphosphate (ATP) production or by stimulating the glymphatic network, we could activate the same plasticity-related pathways as ketamine is capable of activating in mice prefrontal cortex. The results of this study suggest that acute metabolic reduction can trigger pathways regarding synaptic plasticity. The metabolic inhibitor, 2-deoxy-D-glucose and mercaptoacetate (2DG+MA), was found to phosphorylate the TrkB receptor and its downstream signalling molecules GSK3β and p70S6K, while MAPK was dephosphorylated. These results correlate with the previous findings of ketamine’s effect after its administration. We also found a plasticity-related marker, MAP2, to be heavily phosphorylated by 2DG+MA, indicating 2DG+MA having a surprising role on neuroplasticity. These results are promising indication of understanding the rapid effects of ketamine and might even give important insight to developing novel antidepressants. However, these findings are only preliminary, and more research is needed to directly link antidepressant effects and energy metabolic inhibition together, as our study did not directly investigate antidepressants and depression-like behaviour in mice.

Tablet manufacturing requires both high-quality equipment and powder blend with high flowability and compactability and low segregation tendency. The process is complex and tablet formation process still remains not fully understood. Adequate powder flow is a necessity for the pharmaceutical manufacturing process, i.e., powder flowability and flow properties play a great role when designing manufacturing processes for solid dosage forms. As such, the powder characteristics need to be investigated. However, one property is seldom enough to predict the flowability of a powder in specific processes and different test methods need to be used to fully understand the tableting performance of a particular powder. It is crucial to know how the assessed properties reflect the manufacturing conditions. The need for test batches and the use of empirical testing still exists despite the numerous powder characterization tests available. The main aim of the study was to understand the influence of material properties, flow properties and segregation tendencies on both the processability of a formulation during tablet compression and the critical quality attributes, such as mass, tensile strength and dose uniformity of the final drug product. Additionally, testing of an in-line NIR method to observe the homogeneity of the powder inside the force feeder right before the compression step and transmission Raman as an at-line method for tablet content were also evaluated. A number of powder characterization tests were employed in order to fully understand the impact of the formulation on the process performance. Three formulations with different particle size of the active substance and mannitol were used throughout the study. Both the sifting segregation and fluidization segregation tests’ results predicted the formulations’ tabletability particularly well. Fluidization segregation test predicted the changing composition of the formulation throughout tableting whereas sifting segregation results showed the constantly fluctuating API concentration in the manufactured tablets. Moreover, the Raman results confirmed the tablets of variable content despite the offset caused by the different particle size of the raw materials used. The functionality of the NIR in the force feeder was tested successfully. The residence time distribution could be determined at a sufficient level to point out tablets of a bad quality from the batch on grounds of the NIR data. Results from the powder flow property tests were rather conflicting. Angle of repose, Carr’s index and volume flow rate gave the best characterizing results, whereas the mass flow rate, shear test with higher normal stress in pre-shear gave the worst results, considering the experienced flow character of the formulations. As stated above, different flow property tests may give conflicting result, and hence, it is crucial to know which results are the most relevant ones. Furthermore, the right settings for the test should be known to gain applicable results, best exemplified by the shear cell test.

Heart failure is a major public health problem and a leading cause of mortality worldwide. The most common cause of heart failure is myocardial infarction. Following a myocardial infarction, a large number of cardiomyocytes die and cardiac muscle is replaced by fibrotic scar tissue. Since the adult heart has inadequate endogenous regenerative capacity, loss of muscle tissue often causes a progressive decrease in cardiac function eventually leading to heart failure. At the moment heart transplantation is the only curative treatment for heart failure, but the low number of donor hearts is limiting the use of this treatment option. As current drugs only slow down the progression of the disease, there is a great need for new regenerative treatments. Direct cardiac reprogramming is a new approach for generating cardiomyocytes for cardiac regeneration. Unlike pluripotent stem cell-based strategies, direct reprogramming enables conversion of a terminally differentiated cell type directly into another cell type without first producing a pluripotent intermediate. Due to their abundancy and role in the repair of myocardial injury, fibroblasts represent an attractive starting cell type for direct cardiac reprogramming. Fibroblasts have been directly reprogrammed to induced cardiomyocytes (iCMs) by overexpression of key cardiac transcription factors, microRNAs (miRNA) or by modulating specific signal transduction pathways with small-molecule compounds. Despite successful reports of direct reprogramming both in vitro and in vivo, the efficiency of direct reprogramming remains, however, too low for potential clinical applications. The aim of this M.Sc. thesis work was to establish direct reprogramming of mouse embryonic fibroblasts (MEFs) to iCMs by viral overexpression of cardiac transcription factors Hand2 (H), Nkx2.5 (N) Gata4 (G), Mef2c (M) and Tbx5 (T) and a small-molecule compound screening platform for identifying small-molecule compounds that could enhance the reprogramming efficiency and potentially replace cardiac transcription factors in direct cardiac reprogramming. In accordance with previous publications MEFs were successfully directly reprogrammed to iCMs using both HGMT and HNGMT cardiac transcription factor combinations. The screening platform was tested using the TGF-β inhibitor SB431542, which has recently been reported to increase the cardiac reprogramming efficiency. In line with previous publications, the reprogramming efficiency was significantly increased by treatment with SB431542. Initial tests with other small-molecule compounds did not have a positive effect on the reprogramming efficiency. The results of this M.Sc. thesis work verify previous publications and demonstrate a method for in vitro small-molecule compound screening, which can be used to identify compounds that increase the reprogramming efficiency in direct cardiac reprogramming. However, the results shown here are only preliminary and more replicates are needed in order to confirm the current results. Nonetheless, the results of this thesis work set a foundation for finding small-molecule compounds that in the future might be used to target direct cardiac reprogramming as a regenerative therapy for myocardial infarction and heart failure.

The p53-family consists of three transcription factors, p53, p73 and p63. The family members have similar but also individual functions connected to cell cycle regulation, development and tumorigenesis. p53 and p73 act mainly as tumor suppressors. During DNA damage caused by anticancer drugs or irradiation, p53 and p73 levels are upregulated in cancer cells leading to apoptosis and cell cycle arrest. p53 is mutated in almost 50 per cent of the cancers, causing the cancer cells unable to undergo cell death. Instead, p73 is rarely mutated in cancer cells and because of that could be more viable target for anticancer therapy. The network surrounding the regulation of p73 is extensive and has several potential targets for cancer therapy. One of the most studied is Itch ligase, the negative regulator of p73 levels. Gene therapy directed towards knockdown of Itch ligase is a potential approach but in need for more in vivo proof. p73 has two isoforms, transactivating TA-forms and dominant-negative ΔN-forms. The specific regulation of these isoforms could also offer a possible way for more effective cancer treatment. The literature work includes information of structures, isoforms, functions and possible therapeutic targets of p73. Also the main therapeutic approaches to date are introduced. The experimental part is based on transfection and cytotoxicity studies done e.g. in pancreatic cancer cells (Mia PaCa-2, PANC1, BxPc-3 and HPAC). The aim of the experimental work was to optimize the conditions for effective transfection with DAB16 dendrimer nanoparticles and to measure the cytotoxicity of plain dendrimers and DAB16-pDNA complexes. Also the protein levels of p73 and Itch ligase were measured by Western blotting. The work was done as a part of a bigger project, which was aiming to down regulate Itch ligase (negative regulator of p73) by siRNA/shRNA. Tranfection results were promising, showing good transfection efficacy with DAB16 N/P30 in pancreatic cancer cells (except in BxPc-3). Pancreatic cancer cells showed recovery in 3 days after they were exposed to plain dendrimer solution or to DAB16-pDNA. Measurement of protein levels by Western blotting was not optimal and the proposals for the improvement regarding e.g. the gels and the extracted protein amounts have been done.

Functional in vitro cultured human hepatocytes are needed in different applications in biomedical research. Treatment for liver diseases is usually liver transplantation, but due to the lack of healthy donors, cell therapy using hepatocytes is considered as a better option. Drug industry will also need representative liver models to test metabolic profiles of drug molecules. Primary human hepatocytes are studied in cell therapy and disease modelling, but they have also drawbacks. In vitro they do not proliferate efficiently, and they are short-lived. In vitro differentiated human pluripotent stem cells (hPSCs) to hepatic fate are an alternative for the primary human hepatocytes. Especially human induced pluripotent stem cells (hiPSCs) are widely studied because they are easily available, and they even make personalized therapy possible without problems with ethical issues related to the human embryonic stem cells (hESCs). Differentiation to hepatic fate includes several steps before mature functional hepatocyte-like cells are formed. Hepatocytes are derived from the definitive endoderm (DE) which is one of the germ layers formed in the gastrulation process. Efficient induction of hPSCs into DE lineage would be a good starting point for generating mature hepatocyte-like cells in further hepatic differentiation. Different protocols to differentiate hPSCs in vitro into DE have been published. In vitro cell culture systems should well represent the environment of the target tissue because signals from the environment guide the differentiation. Three-dimensional (3D) cell culture systems are widely studied, because they better mimic the in vivo microenvironment of cells than two-dimensional (2D) cell culture. The aim of the thesis was to study the efficacy of the 3D differentiation of hiPSCs into DE. Before starting the 3D differentiation, differentiation protocol was optimized and the effect of ROCK inhibitor Y-27632 was investigated. Differentiation medium was supplemented with Y-27632 during the whole 6 days differentiation, because survival of the cells and formation of the spheroids were improved, and gene expression studies of pluripotency markers and several DE markers did not show evident effect of Y-27632 on the gene expression of hiPSCs. The main objective in the studies was also to investigate possible differences between different 3D culture conditions on hiPSCs differentiation into DE. Also, the effect of the spheroid size on differentiation was examined. Two different hydrogels were used as a matrix material in the experiments: basement membrane extract (BME) and nanofibrillar cellulose (NFC) hydrogels. Suspension culture was used as a biomaterial-free 3D culture system. Experiments were performed with three spheroid sizes: 200 cells/spheroid, 500 cells/spheroid and 1000 cells/spheroid. Efficacy of differentiation to DE lineage was estimated by studying protein and mRNA expression of some of the DE markers (HNF3B, SOX17, CXCR4, CER1), pluripotency marker OCT4, mesendoderm marker Brachyury and hepatoblast marker HNF4A in the cells. Spheroids differentiated in suspension and NFC were analysed by flow cytometry to get the number of DE positive live cells and dead cells using CXCR4 and 7-AAD double staining. Besides flow cytometry, protein expression of some of the key markers were studied by immunofluorescent staining and further confocal imaging. Viability of the spheroids in BME hydrogel culture were investigated using live/dead staining followed by confocal imaging. BME hydrogel culture was left out from the further experiments due to the morphology of the spheroids and results from viability and protein expression studies. Spheroids in suspension started DE differentiation faster compared to NFC culture. Suspension and NFC cultures yielded high number of double positive cells in flow cytometry and bright fluorescence of other DE markers was seen in the confocal images. NFC hydrogel proved to be a promising 3D culture system by supporting the differentiation of hiPSCs. Flow cytometry results and gene expression studies propose that four days long 3D differentiation would be efficient to produce sufficient number of DE cells. Smaller spheroids showed higher number of DE positive cells than bigger spheroids on day 2 but gene expression studies showed difference in DE marker expression between size conditions rather in later days in differentiation and it was the opposite. Experiments showed signs of more efficient differentiation of the smaller sized spheroids in the beginning of differentiation. But further studies are needed to verify the obtained results and both draw conclusions about the possible differences between different 3D culture systems and explore the best size of the spheroid for hepatic differentiation. However, results obtained from the studies are useful for designing further experiments.

OATP2B1 is a transmembrane transport protein expressed widely in the human body and transports both endogenous compounds and several drugs from outside the cell into the cytoplasm. The abundant expression of OATP2B1 in pharmacokinetically important tissues such as in the intestine, liver, and kidney suggests an important role in the drug absorption and elimination process, although research data on the clinical significance of OATP2B1 is still limited. Several drugs inhibit the function of OATP2B1, creating a risk for drug-drug interactions. OATP inhibition by some inhibitors is time-dependent, which may lead to more potent in vivo effects than expected. In this study, the time dependence of OATP2B1 inhibition by five different drugs was evaluated using OATP2B1-overexpressing HEK293 cells. IC50 values of inhibitors for OATP2B1-mediated uptake of DBF and E1S were determined with and without preincubation for 20 minutes. In addition, the in vivo interaction potential of the inhibitors in the intestine, liver, and other tissues was evaluated by utilizing the FDA and EMA guidelines. All five drugs showed effective and concentration-dependent OATP2B1 inhibition with IC50 values of 0.12– 8.82 µM. Furthermore, the inhibition of OATP2B1-mediated DBF uptake by ticagrelor and atorvastatin was time-dependent, while the effect of pre-incubation remains below the limit for the other inhibitors. The inhibitory effect of ticagrelor continued even after the inhibitor was removed from the inhibition buffer. All five inhibitors showed the potential to cause in vivo OATP2B1 inhibition in the intestine, which could result in decreased absorption of the co-administered substrate drug. About erlotinib, the risk of interaction also appeared in the liver, which could reduce the transfer of the substrate drug to the liver and thus lower its elimination rate. In this study, pre-incubation did not affect the in vivo interaction potential of the inhibitor drugs. The results indicate that drug-induced inhibition of OATP2B1 may be time-dependent and therefore can lead to interactions at lower concentrations than expected. For this reason, evaluating the time dependence would be appropriate when assessing transport protein-mediated interaction risk. The results of this study can be utilized in designing clinical interaction studies and in understanding the results.

Hepatitis C virus disease is transmitted through blood. Chronic hepatitis C causes liver damages such as liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. It is estimated that there are approximately 20 000 - 30 000 patients infected with hepatitis C virus in Finland. For many years pegylated interferon and ribavirin has been standard of care. However standard of care causes side effects and an adequate treatment response can't be achieved with it. There have been effective direct-acting antivirals available on market which are directed against structural proteins and enzymes of the virus from 2014 onward. These second generation direct-acting antivirals are effective, safe and well tolerated. The only disadvantage is the high price of these medicines which restricts them for severe liver damage patients. More information about cost-effectiveness of second generation direct-acting antivirals is needed to support the decision making. The aim of this master thesis is to describe current care, guidelines, and costs of hepatitis C in Finland. Thesis also describes the principles of economic evaluation and systematic literature review. The purpose of the thesis is to assess cost-effectiveness of second generation direct-acting antivirals versus standard of care in treating of hepatitis C by means of systematic literature review and evaluate the quality of cost-effectiveness analyses. Previously published studies were used to analyze the cost-effectiveness of second generation direct-acting antivirals. In total of 435 references were found through systematic literature search. In addition, two studies were found from the bibliographies of already included studies. Altogether 26 studies were included in the systematic review of which 25 were original studies and one was previously published systematic literature review. The most relevant data of the studies was gathered and analyzed. The quality of the studies was assessed by using three checklists. It is difficult to make conclusions about cost-effectiveness of second generation direct-acting antivirals based on previously published reviews because only one review was found through systematic literature search. The incremental cost-effectiveness ratio (ICER) of second generation direct-acting antivirals varied between dominance and 1 135 655 € /QALY compared to standard of care. When compared to another second generation direct-acting antiviral, ICER of second generation direct-acting antivirals varied between dominance and 65 281 € /QALY. It was also analyzed how stage of liver damage affects the incremental costeffectiveness of second generation direct-acting antivirals. The ICER of second generation direct-acting antivirals was between 299 € - 85 195 € /QALY when treating patients with cirrhosis. When treating non-cirrhotic patients, the ICER of second generation direct-acting antivirals was between 2182 € - 177 679 € /QALY.The connection between funder of the study and the ICER of second generation direct-acting antivirals was also analyzed. The ICER was 1717 € - 86 056 € /QALY in studies funded by pharmaceutical company. The ICER was 299 € - 1 135 655 € /QALY in studies funded by other party. Based on the results of the thesis second generation direct-acting antivirals might be cost-effective compared to current standard of care in treating hepatitis C. The cost-effectiveness ratio of second generation direct-acting antivirals is lower in cirrhotic patients than in non-cirrhotic patients. The incremental cost-effectiveness ratio is lower when pharmaceutical company funds a study. The quality of the cost-effectiveness analyses included in the thesis varied greatly which makes it difficult to draw conclusions and interpretate the results. This study has several strengths. First, literature search was conducted systematically and transparently. Second, quality of the reviewed studies included was assessed by care. Finally, reporting of the results is transparent and repeatable. The study has also some limitations. Selection of the reviewed studies, data extraction and quality assessment of the studies was conducted by one person which may increase the possibility of human error.

Tramadol products for cats are not commercially available. Problems may occur when dividing a tablet registered for humans due to uneven distribution of active ingredient within a tablet and bitter taste of tramadol. Minitablets have multiple benefits, including small size, better uniformity of content, coatability and fast administration, in comparison to a divided conventional tablet. The purpose of this study was to develop minitablets which are possible to coat with a taste masking coating. Physical and chemical properties of tramadol hydrochloride, such as water solubility, temperature behavior and hygroscopicity were studied. Additionally, compatibility of tramadol hydrochloride with excipients was studied by a 3-month stability exam. The pre-tests of granulation were carried out by using lactose or ascorbic acid as an active ingredient to model tramadol hydrochloride. The granulation was performed with high shear granulator and tableting with a rotary tablet press. The only variable factor between the granulation batches was the amount of granulation fluid. The impact of the amount of granulation fluid to the tableting properties was examined by determining particle size distribution, Carr index and Hausner ratio. Uniformity of mass, uniformity of content, hardness, disintegration time and dissolution were examined. The study revealed that tramadol hydrochloride did not have incompatibilities with the examined excipients. Tramadol hydrochloride was not hygroscopic even though it was found out to be freely soluble in water. Tablets with adequate hardness were successfully compressed of both granulated masses and the direct compression mass. However, the direct compression mass had more undesirable properties regarding the processes. Most batches fulfilled the requirements set for uniformity of mass and uniformity of content. Although the purpose of this study was to develop a tablet for veterinary medicine, the results in this study may be utilized in developing a formulation for pediatric medicine.

In recent years, animals have been recognized as promising next-generation protein production systems. Animal transgenesis has been achieved primarily in insect cells infected by recombinant baculoviruses. Baculovirus Expression Vector Systems (BEVS) transform the DH10Bac strain of Escherichia coli with the shuttle vector to produce recombinant baculovirus carrying the cargo of interest. The cargo includes at least one promoter driving the expression of at least one protein. PGK is a strong promoter that is naturally active in almost all species where it has been tested, including invertebrates like Drosophila. The PiggyBac transposon-based system is a known strategy for genome integration of foreign genes to create transgenic animals. Nevertheless, nobody has used baculoviruses to deliver genes and produce proteins in earthworms nor to create transgenic earthworms. There is also no information on the sequence of any endogenous E. fetida (earthworm) promoter yet. This project aimed to pilot a novel gene delivery method by creating baculoviruses through the BEVS, carrying the PGK promoter and the GFP reporter gene, and to assess the promoter activity in both Sf9 insect cells and E. fetida through evaluation of GFP fluorescence. Another target was to test the fluorescence after the addition to the baculovirus of the PiggyBac-based inverted terminal repeats (ITRs), flanking the PGK-GFP transcriptional unit. The secondary objective was to develop a non-lethal method for live worm imaging. Conventional restriction enzyme cloning was used to create the shuttle vectors, and restriction digest and Sanger Sequencing were used to identify the positive clones. The Bac-to-Bac BEVS was followed to create baculovirus particles carrying the cargo (PGK-GFP and PGK-GFP-ITR), infect Sf9 insect cells and monitor the PGK activity. Prior to in vitro transfection, the bacmid DNA was confirmed by PCR. These baculoviruses were also used to infect E. fetida and monitor the PGK activity in vivo. E. fetida autofluorescence was assessed before infection. PGK resulted in being much weaker in Sf9 than expected. The flanking of the transcriptional unit of GFP with the ITRs improved the GFP expression. 16% ethanol was shown to anaesthetize E. fetida for 10 to 15 minutes safely. Wild-type and starved E. fetida were shown to have very mild autofluorescence in their digestive system and setae. The coelomic fluid was shown to have strong autofluorescence. Thus, its excretion is crucial before imaging GFP. Likely, all the in vivo fluorescence after infection was due to the worm’s autofluorescence. Therefore, PGK and GFP were unlucky choices for E. fetida.

A notable amount of the R&D resources of the proprietary drug firms seems to be directed towards the improvement of existing drugs. Hypothetically, this may lead to interesting formulation development strategies. The purpose of the study was to find out, whether any trends in pharmaceutical product development could be detected from data on granted marketing authorisations. Also the lifecycle management approaches the major pharmaceutical companies use to protect their blockbuster products from generic competition and to ensure their market share were in the interest of this study. The emphasis of the study was on oral solid dosage forms. A combination of qualitative and quantitative methods was employed to obtain a wide view on the subject of the study. Qualitative interviews with the Finnish regulatory authorities were used to collect background information for the quantitative part, which consisted of the marketing authorisation databases covering all MA procedures in Finland, the centralised procedure in the EU, and world's ten major pharmaceutical companies in the US. Based on the study results, there was a remarkable rise in the proportion of generic products of all MAAs authorised in Finland and through the centralised procedure within the European Union during 2000-2010. This change may be at least partly amounted to the legislative changes creating incentives for the use and the manufacture of generic drug products, such as the generic substitution and the reference pricing systems. The US data showed the inclination of the big pharma towards lifecycle management: the majority of the new MAs granted to the world's ten major pharmaceutical companies in 2005-2010 were for this purpose. The ratio of lifecycle management to new molecular entities was almost 4:1. Solid oral dosage form is undeniably the most popular method of drug administration, which was confirmed by the expert interviews and the marketing authorisation data as well. The role of oral solids was even more pronounced within the generic MAs. When innovation was measured by the proportion of non-conventional dosage forms, the US data on solid oral dosage forms indicated strong innovation compared to the Finnish or EU data. This may reflect the innovative product portfolio of the major pharmaceutical companies. The proportion of non-conventional oral solid dosage forms was remarkably smaller in generic than in reference products across all regions. In lifecycle management, the most commonly used strategies were new formulation, new strength or new combination of an existing product. Within the solid oral dosage forms, two-thirds of the new LCM formulations were modified-release preparations. Lifecycle management is an essential part of the major pharmaceutical companies' business strategy, the importance of which was illustrated by the case study of Coreg tablets.