The impact of serotonin on mental health in dogs with focus on aggression and anxiety

Behavioural problems in dogs might affect the welfare of both humans and dogs negatively. Today, psychological diseases such as depression, are common in humans. In contrast, in dogs, behavioural problems associated with separation and anxiety are commonly reported. Serotonin has appeared to be important for development of depression in humans, and it can therefore be interesting to study if changes in serotonin levels are correlated to behavioural problems in dogs as well. This literature study aims to investigate if there are associations between serotonin and behaviour in dogs and if breed, gender, feed and exercise can affect the serotonin concentration. Since the literature mainly reports studies on aggression and anxiety in dogs this literature study focuses on these issues. Serotonin is a biogenic amine, synthesized from tryptophan, and can be classified as neurotransmitter, a hormone or a mitogen. It has several functions and operates for example in the central nervous system, the gastrointestinal tract and the cardiovascular system. There are seven subtypes of serotonin receptors which are called 5-HT1-7. The serotonin concentration has been reported to be lower in aggressive and anxious dogs. The concentration may be affected by breed, and possibly by gender and age. A larger amount of tryptophan in the food can have an impact on the concentration, as well as exercise. However, further research is required since many of the studies show contradictory results.Beteendeproblem hos hund kan påverka både människors och hundars välfärd negativt. Psykisk ohälsa, som depression, är idag mycket vanligt hos människor. Hos hundar rapporteras istället ofta orosrelaterade beteendeproblem såsom separationsångest och rädslor. Hos människa har serotonin visat sig ha betydelse för utvecklandet av depression, och det kan därför vara av intresse att undersöka om det finns motsvarande samband hos hund. Syftet med denna litteraturstudie är att undersöka hur sinnesstämningen hos hund påverkas av serotonin, samt om ras, kön, ålder, foder och motion har någon inverkan. Då merparten av litteraturen behandlar aggressivitet och oro hos hund har denna litteratursammanställning fokuserat på detta. Serotonin syntetiseras från tryptofan och är en biogen amin som kan fungera som neurotransmittor, hormon eller mitogen. Serotonin har flera olika funktioner, bland annat verkar substansen i det centrala nervsystemet, magtarmkanalen och i hjärt-kärlsystemet. För närvarande finns sju huvudgrupper av serotoninreceptorer som kallas för 5-HT1-7. Det tycks finnas vissa samband mellan serotonin och sinnesstämning hos hund och serotoninkoncentrationen tycks ofta kunna vara lägre hos aggressiva och oroliga hundar. Koncentrationen har rapporterats kunna påverkas av hundens ras, och möjligtvis kön och ålder. En högre andel tryptofan i fodret kan eventuellt ha en inverkan på koncentrationen och även hundens motion kan möjligtvis påverka serotoninnivåerna. Flera studier visar dock motsägelsefulla resultat och ytterligare forskning inom området behövs

Mänsklig omvårdnadsstils inverkan på bandet mellan hund-människa

Research about attachment behaviours of dogs as a response to human caregiving behaviour as well as the owner’s view of the relationship, is of relevance for the welfare of the dog and the owner. Dogs have been obser-ved showing similar attachment behaviours toward humans as seen in child-ren toward a parent. There are four different attachment styles defined wit-hin the human psychology; insecure anxious, insecure avoidant, secure and disorganised attachment. A person with one type of adult attachment style usually has a corresponding caregiving style. These caregiving styles have been applied within the anthrozoology through surveys and during studies of dog behaviour during challenging situations. The caregiving styles secure and disorganised and their impact on behaviour in Beagles in chal-lenging situations has been studied at the Swedish University of Agricultural Sciences (SLU) in 2017. In 2019, a similar study was performed with Beag-les at SLU with the two other caregiving styles, insecure avoidant and insecure anxious. The main aim of this master’s thesis was to investigate if there were any correlations between human caregiving styles and the dog’s support seeking behaviour, with focus on the insecure avoidant and insecure anxious caregiving style. This part was performed during a practical study where the behaviour of Beagle dogs was studied during three types of chal-lenging situations; a visual surprise, a sudden noise and during the appro-ach of a strange looking person. These tests were done before and after an interaction period of 15 days. The dogs interacted with an insecure avoidant and an insecure anxious test person during approximately 20 minutes per person and day. Moreover, the adult attachment style (our indirect measure of caregiving) of owners of private dogs and their satisfaction of the relat-ionship with their dog was correlated to the dog’s behaviour during chal-lenging situations. This latter part was performed using volunteer dog owners and their dog’s results from the dog mentality assessment (DMA). The practical study showed that the dogs initiated contact seeking behav-iours toward both persons with an avoidant caregiving style and an anxious caregiving style, suggesting that the dogs’ preferences of caregiving might vary according to their own basic temperament. The survey revealed that owners’ adult attachment style (human caregiving style) correlated with the dog owners’ view of the relationship to their dog, which might have similari-ties with their view of relationship to humans. The response of the dog to the challenging situations measured in the DMA correlated with the quality of the bond between dog and human and might be affected by owner ca-regiving style. Further studies are required to investigate what an impact these relations might have on everyday life for the welfare of dog and hu-man.Forskning om hur anknytningsbeteende hos hund påverkas av mänsklig omvårdnadsstil samt hur hundägare uppfattar relationen till sin hund, är relevant för hundens och ägarens välfärd. Hundar har uppvisat anknyt-ningsbeteenden gentemot sina ägare på ett liknande sätt som observerats hos barn gentemot sina föräldrar. Det finns fyra olika anknytningsstilar de-finierade inom humanpsykologin; osäker-ambivalent, osäker-undvikande, säker samt den desorganiserade/oförutsägbara. En person med en slags vuxen anknytningsstil har vanligtvis motsvarande omvårdnadsstil. Omvård-nadsstilarna har studerats inom antrozoologin genom enkäter och vid stu-dier av hundars beteende under utmanande situationer. Den säkra och des-organiserade/oförutsägbara omvårdnadsstilen och dess påverkan på beag-lar under utmanande situationer har studerats under år 2017 på Sveriges lantbruksuniversitet (SLU). Under år 2019 har en liknande studie genomförts med beaglar på SLU med de två andra omvårdnadsstilarna, osäker-ambivalent samt osäker-undvikande. Det huvudsakliga syftet med examensarbetet var att undersöka om det finns korrelationer mellan mänsklig omvårdnadsstil och hundars kontaktsö-kande/stödsökande beteenden, med fokus på den osäkra-ambivalenta samt osäkra-undvikande omvårdnadsstilen. Detta studerades vid en prak-tiskt studie då beteende hos beaglar observerades under tre utmanande situationer; en visuell överraskning, plötslig ljudöverraskning samt under närmandet av en främmande person. Dessa tester genomfördes före samt efter en interaktionsperiod av 15 dagar. Hundarna fick under denna period interagera med en osäker-ambivalent samt en osäker-undvikande testper-son under ungefär 20 minuter per person och dag. I tillägg korrelerades den vuxna anknytningsstilen (vårt indirekta mått på omvårdnadsstil) för ägare av privata hundar och hur nöjda de var med relationen till sin hund till hundens beteende under utmanande situationer. Detta genomfördes med hjälp av frivilliga hundägare och deras resultat från Mentalbeskrivning Hund (MH). Resultatet av den praktiska studien visade att hundarna initierade kontakt-sökande/stödsökande beteenden gentemot både personer med en osäker-ambivalent omvårdnadsstil samt en osäker-undvikande omvårdnadsstil och att deras preferenser av omvårdnadsstil kan variera, vilket möjligen kan vara relaterat till deras grundtemperament. Enkätresultatet visade att hundägares vuxna anknytningsstil (mänsklig omvårdnadsstil) korrelerade med hundägarnas uppfattning av relationen till sin hund, vilken kan ha lik-heter med deras uppfattning av relationer till andra människor. Hundens beteende under de utmanade situationerna i MH korrelerade med ägarens belåtenhet med relationen till sin hund och påverkas möjligen av ägarens omvårdnadsstil. Fortsatta studier krävs för att undersöka inverkan av dessa samband på vardagslivet för hundens och ägarens välfärd

Zebrafish patient-derived xenograft models predict lymph node involvement and treatment outcome in non-small cell lung cancer

Background Accurate predictions of tumor dissemination risks and medical treatment outcomes are critical to personalize therapy. Patient-derived xenograft (PDX) models in mice have demonstrated high accuracy in predicting therapeutic outcomes, but methods for predicting tumor invasiveness and early stages of vascular/lymphatic dissemination are still lacking. Here we show that a zebrafish tumor xenograft (ZTX) platform based on implantation of PDX tissue fragments recapitulate both treatment outcome and tumor invasiveness/dissemination in patients, within an assay time of only 3 days. Methods Using a panel of 39 non-small cell lung cancer PDX models, we developed a combined mouse-zebrafish PDX platform based on direct implantation of cryopreserved PDX tissue fragments into zebrafish embryos, without the need for pre-culturing or expansion. Clinical proof-of-principle was established by direct implantation of tumor samples from four patients. Results The resulting ZTX models responded to Erlotinib and Paclitaxel, with similar potency as in mouse-PDX models and the patients themselves, and resistant tumors similarly failed to respond to these drugs in the ZTX system. Drug response was coupled to elevated expression of EGFR, Mdm2, Ptch1 and Tsc1 (Erlotinib), or Nras and Ptch1 (Paclitaxel) and reduced expression of Egfr, Erbb2 and Foxa (Paclitaxel). Importantly, ZTX models retained the invasive phenotypes of the tumors and predicted lymph node involvement of the patients with 91% sensitivity and 62% specificity, which was superior to clinically used tests. The biopsies from all four patient tested implanted successfully, and treatment outcome and dissemination were quantified for all patients in only 3 days. Conclusions We conclude that the ZTX platform provide a fast, accurate, and clinically relevant system for evaluation of treatment outcome and invasion/dissemination of PDX models, providing an attractive platform for combined mouse-zebrafish PDX trials and personalized medicine