Investigation of the safety profile of polymeric nanomedicines in vitro via assessment of macrophage and hepatocyte responses

Nanoparticles (NPs) can be used in clinical applications (e.g. for drug delivery or bioimaging) in order to better treat and diagnose disease. Many nanomedicines are made from polymers, and improvements in polymer NP synthesis methods have made it easier to design and synthesise complex and diverse polymer NPs (PNPs) for clinical use. However, investigation into PNP safety has lagged behind their development, resulting in uncertainties regarding the safety of these PNPs. In vitro studies conducted to date have focused on assessment of cytotoxicity and cytokine production to screen the toxicity of nanomedicines. Micelles are one of the most attractive PNPs for medical use as they have a hydrophobic core that can carry cargo and a hydrophilic shell that interacts with the exterior environment. A panel of micellar PNPs of varying complexity were selected for investigation in this study. In the first instance, a novel polymer was used to generate poly (decamethylene succinate-co-pheylsuccinate) (PDP) NPs to investigate the influence of an adsorbed pluronic acid (PF68) coating on the toxicity of NPs. Next, the impact of polylactic-co-glycolic acid (PLGA) chain length (4K, 15K and 55K) on PNP toxicity was investigated. Finally, the toxicity of redox-reactive (RR)-NPs, composed from PLGA, was compared to NPs which lacked this element (nRR-NP). All NPs tested had a polyethylene glycol (PEG) element in the shell. PNP safety was investigated via assessment of cytotoxicity, cytokine production, cellular uptake, genotoxicity, reactive oxygen species (ROS) production, urea and albumin production and intracellular calcium concentration ([Ca2+]i). The toxicity of the PNP panel to the C3A hepatocyte cell line was assessed in vitro as it is established that NPs administered via various routes (e.g. inhalation, ingestion, intravenous injection) accumulate in the liver. There was little to no cytotoxicity observed for all PNPs. Uptake of the PDP NPs by C3A cells was greatest, but low for 4K, 15K, 55K, RR and nRR NPs. PDP-PF68 PNPs and nRR-NPs induced genotoxicity via an oxidative mechanism, whereas the other NPs did not. Production of the anti-inflammatory cytokine interleukin (IL)-1ra, was elevated. No change in the production of the other cytokines (e.g. IL-8. Tumour necrosis factor (TNF)α, IL-1β) was observed. ROS production was elevated by all PNPs investigated. Liver-specific markers of toxicity (urea and albumin production) were decreased for all PNPs investigated, with the greatest effect observed for nRR-NPs. A slight increase in [Ca2+]i was observed for cells exposed to RR-NPs. The findings obtained allowed the physicochemical properties of the PNPs which conferred toxicity to be identified; this can inform the design of PNPs in the future. More specifically, the addition of a PF-68 shell or a redox-responsive linker increased the safety of the PNPs. However, increasing chain length enhanced PNP toxicity. This study could also aid in developing evidence-based in vitro approaches to screen PNP safety, and therefore contribute to the development of a tiered testing strategy to facilitate assessing the toxicity of future generations of PNPs. By using a battery of tests to screen the toxicity of the PNP panel in this study a comprehensive assessment of PNP safety was performed, and the findings provided insight into their mechanism of action

A review of hepatic nanotoxicology - summation of recent findings and considerations for the next generation of study designs

The liver is one of the most important multi-functional organs in the human body. Amongst various crucial functions, it is the main detoxification center and predominantly implicated in the clearance of xenobiotics potentially including particulates that reach this organ. It is now well established that a significant quantity of injected, ingested or inhaled nanomaterials (NMs) translocate from primary exposure sites and accumulate in liver. This review aimed to summarize and discuss the progress made in the field of hepatic nanotoxicology, and crucially highlight knowledge gaps that still exist. Key considerations include In vivo studies clearly demonstrate that low-solubility NMs predominantly accumulate in the liver macrophages the Kupffer cells (KC), rather than hepatocytes. KCs lining the liver sinusoids are the first cell type that comes in contact with NMs in vivo. Further, these macrophages govern overall inflammatory responses in a healthy liver. Therefore, interaction with of NM with KCs in vitro appears to be very important. Many acute in vivo studies demonstrated signs of toxicity induced by a variety of NMs. However, acute studies may not be that meaningful due to liver’s unique and unparalleled ability to regenerate. In almost all investigations where a recovery period was included, the healthy liver was able to recover from NM challenge. This organ’s ability to regenerate cannot be reproduced in vitro. However, recommendations and evidence is offered for the design of more physiologically relevant in vitro models. Models of hepatic disease enhance the NM-induced hepatotoxicity. The review offers a number of important suggestions for the future of hepatic nanotoxicology study design. This is of great significance as its findings are highly relevant due to the development of more advanced in vitro, and in silico models aiming to improve physiologically relevant toxicological testing strategies and bridging the gap between in vitro and in vivo experimentation

Ulkomaalaisten asiakkaiden hotellin valintaan vaikuttavat tekijät. Case Sokos Hotel Ilves

Tamperella on lukuisia hotelleja ja hostelleja, joista asiakas voi valita mieleisensä majoituspaikan saapuessaan kaupunkiin. Mikä saa asiakkaan valitsemaan tietyn hotellin näiden kaikkien vaihtoehtojen joukosta? Tutkimuksen tavoite oli selvittää, miksi ulkomaalaiset asiakkaat ovat valinneet Tampereen hotelleista juuri Sokos Hotel Ilveksen viipymänsä ajaksi. Suomeen saapuvien ulkomaalaisten asiakkaiden määrä on kasvussa ja heidän viipymänsä keston keskiarvo on suurempi kuin suomalaisilla asiakkailla. Siksi heidän ostopäätösprosessinsa tutkimisen merkitys on yhä tärkeämpää. Tutkimuksen teoriaosa käsittelee ostopäätösprosessia, ostohaluun vaikuttavia tekijöitä ja itse ostoprosessia. Tutkimuks toteutettiin kvalitatiisena tutkimuksena ja tiedonkeruumenetelmänä käytettiin kyselylomaketta. Kyselyn vastaajina toimivat Sokos Hotel Ilvekseen saapuvat ulkomaalaiset asiakkaat. Tutkimuksen aineisto käsiteltiin hyödyntämällä SPSS- ohjelmaa sekä Microsoft Exceliä. Kyselylomakkeiden avulla kerätyn datan lisäksi tuloksien analysoinnissa hyödynnettiin myös tekemiäni havaintoja työskennellessäni itse Ilveksen vastaanotossa. Tutkimuksen tulokset osoittavat eroja Sokos Hotel Ilveksen ulkomaalaisten asiakkaiden ostopäätösprosessissa riippuen asiakkaan demograafisesta, sosisaalisesta ja psykologisesta taustasta. Näitä eroja on tarkasteltu vertaamalla mm. työ- ja vapaa-ajan matkustajien vastauksia. Tuloksia voidaan hyödyntää segmentoinnin ja markkinoinnin kehittämisessä.There are many hotels and hostels in Tampere to choose from when a customer arrives in Tampere. What makes the customer choose a certain hotel from the range of choices he/she has? The purpose of the study was to find out why foreign customers who arrive at Tampere choose Sokos Hotel Ilves from all the hotels in the city. The number of foreign customers who come to Finland is growing and their average length of the stay is longer than the Finnish customers'. For that reason it is even more meaningful to research the foreign customers' consumer behaviour more. The theoretical part of my study deals with the buying decision process and factors that affect consumers' needs to buy different things. The study was conducted using qualitative methods. The data was collected by using questionnaires. The respondents were foreign customers who arrived in Sokos Hotel Ilves. The data was analyzed using SPSS software and Microsoft Excel. In addition to analysing the results, I also used the observations I made during the time I was working as a receptionist in Ilves. The results of the study show that there are differences in the buying process depending on the customers' demographical, social and psychological background. The differences between the respondents are compared by dividing them into different groups such as business and leisure travellers. The results of the study can be useful in segmentation and marketing