{"id":6447,"date":"2026-10-19T09:48:55","date_gmt":"2026-10-19T09:48:55","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-heilbrigdisvisindum-birna-gudrun-asbjornsdottir\/"},"modified":"2026-10-19T09:48:55","modified_gmt":"2026-10-19T09:48:55","slug":"doktorsvorn-i-heilbrigdisvisindum-birna-gudrun-asbjornsdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-heilbrigdisvisindum-birna-gudrun-asbjornsdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed heilbrig\u00f0isv\u00edsindum – Birna Gu\u00f0r\u00fan \u00c1sbj\u00f6rnsd\u00f3ttir"},"content":{"rendered":"
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F\u00f6studaginn 26. jan\u00faar 2024 ver Birna Gu\u00f0r\u00fan \u00c1sbj\u00f6rnsd\u00f3ttir doktorsritger\u00f0 s\u00edna \u00ed heilbrig\u00f0isv\u00edsindum vi\u00f0 Matv\u00e6la- og n\u00e6ringarfr\u00e6\u00f0ideild og L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0 Gegndr\u00e6pi \u00fearma, \u00f6rveru-\u00fearma-heila \u00e1s, atferli, og ge\u00f0raskanir barna og unglinga. Ytri og e\u00f0lisl\u00e6g st\u00fdring \u00fearmat\u00e1lmastarfsemi. Intestinal Permeability, Microbiota-Gut-Brain Axis, Behavior, and Mental Disorders in Children and Adolescents. Extrinsic and intrinsic regulation of intestinal barrier function.<\/p>\n

Andm\u00e6lendur eru dr. Dennis Sandris Nielsen, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed Kaupmannah\u00f6fn, og dr. Timothy Dinan, pr\u00f3fessor emeritus vi\u00f0 University College Cork, \u00cdrlandi.<\/p>\n

Umsj\u00f3narkennari og lei\u00f0beinandi var Brynd\u00eds Eva Birgisd\u00f3ttir, pr\u00f3fessor, me\u00f0lei\u00f0beinandi var Bertrand Lauth, d\u00f3sent. A\u00f0rir \u00ed doktorsnefnd voru Magn\u00fas Gottfre\u00f0sson, pr\u00f3fessor, L\u00e1rus Stein\u00fe\u00f3r Gu\u00f0mundsson, d\u00f3sent og Alessio Fasano, pr\u00f3fessor.<\/p>\n

\u00d3l\u00f6f Gu\u00f0n\u00fd Geirsd\u00f3ttir, pr\u00f3fessor og deildarforseti Matv\u00e6la- og n\u00e6ringarfr\u00e6\u00f0ideildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 9.00.<\/p>\n

\u00c1grip<\/strong><\/p>\n

Ge\u00f0raskanir eru fl\u00f3knar fj\u00f6l\u00fe\u00e6ttar raskanir \u00e1 ge\u00f0heilbrig\u00f0i sem rekja m\u00e1 til erf\u00f0a-, umhverfis- og l\u00edfsst\u00edls\u00fe\u00e1tta. \u00de\u00e6r hafa veruleg \u00e1hrif \u00e1 l\u00edfsg\u00e6\u00f0i og framt\u00ed\u00f0arhorfur hj\u00e1 allt a\u00f0 fimmtungi barna og unglinga og eru ein helsta ors\u00f6k langvinns heilsuleysis og \u00f6rorku me\u00f0al ungmenna um allan heim. N\u00fdlegar ranns\u00f3knir hafa beint sj\u00f3num a\u00f0 \u00fearmat\u00e1lma, innsta lagi meltingarvegar sem gegnir tveimur andst\u00e6\u00f0um lykilhlutverkum; a\u00f0 vi\u00f0halda s\u00e9rt\u00e6ku gegndr\u00e6pi nau\u00f0synlegra n\u00e6ringarefna fr\u00e1 \u00fe\u00f6rmum yfir \u00ed bl\u00f3\u00f0r\u00e1s og \u00e1 sama t\u00edma a\u00f0 koma \u00ed veg fyrir innstreymi ska\u00f0legra \u00fe\u00e1tta fr\u00e1 meltingarvegi me\u00f0 st\u00fdr\u00f0u gegndr\u00e6pi. \u00dearmat\u00e1lmastarfsemi hefur \u00e1hrif \u00e1 \u00f6rveru-\u00fearma-heila \u00e1s, samskiptanet sem tengir \u00fearmafl\u00f3ru, meltingarveg, taugakerfi og heila. N\u00fdlegar ranns\u00f3knir benda til a\u00f0 ri\u00f0lun \u00ed \u00feessu samskiptaneti geti tengst ge\u00f0r\u00f6skunum.<\/p>\n

Markmi\u00f0 \u00feessa doktorsverkefnis var a\u00f0 auka \u00feekkingu \u00e1 meinal\u00edfe\u00f0lisfr\u00e6\u00f0ilegum \u00fe\u00e1ttum tengdum ge\u00f0r\u00f6skunum \u00fat fr\u00e1 \u00e1hrifum \u00fearmat\u00e1lmastarfsemi \u00e1 \u00f6rveru-\u00fearma-heila \u00e1s, me\u00f0al annars me\u00f0 f\u00e6\u00f0utengdu \u00e1reiti, og leitast vi\u00f0 a\u00f0 sk\u00fdra m\u00f6guleg orsakatengsl og samverkun undirliggjandi kerfa og ferla. Yfirmarkmi\u00f0i\u00f0 var a\u00f0 rannsaka samspil milli gegndr\u00e6pis \u00fearma og ge\u00f0raskana. S\u00e9rt\u00e6k markmi\u00f0 voru; (I) a\u00f0 taka saman \u00e1 kerfisbundinn h\u00e1tt ni\u00f0urst\u00f6\u00f0ur athugunarranns\u00f3kna \u00e1 gegndr\u00e6pi \u00ed \u00fe\u00f6rmum \u00fat fr\u00e1 magni vi\u00f0eigandi l\u00edfmarka (e. biomarkers) og\/e\u00f0a \u00e1reiti inneiturs (e. endotoxin) hj\u00e1 b\u00f6rnum og unglingum greindum me\u00f0 ge\u00f0raskanir og bera saman vi\u00f0 vi\u00f0mi\u00f0unarh\u00f3pa; (II) rannsaka \u00e1hrif broddmj\u00f3lkur \u00e1 umritunarmengi \u00ed zonulin v\u00edxlgena m\u00fasum (Ztm), \u00e1samt \u00fev\u00ed a\u00f0 rannsaka genatj\u00e1ningu \u00fe\u00e9ttitengja \u00ed \u00feekjuvef eftir \u00edhlutun me\u00f0 broddmj\u00f3lk; (III) rannsaka m\u00f3tandi \u00e1hrif broddmj\u00f3lkur \u00e1 \u00f6rverufl\u00f3ru \u00ed \u00fe\u00f6rmum og atferli villiger\u00f0a (WT) og Ztm m\u00fasa; (IV) hanna, skrifa og gefa \u00fat ritr\u00fdnda ranns\u00f3knar\u00e1\u00e6tlun fyrir l\u00fd\u00f0grunda\u00f0a langt\u00edma tilfella-vi\u00f0mi\u00f0a ranns\u00f3kn \u00fear sem matar\u00e6\u00f0i, \u00fearmafl\u00f3ra, gegndr\u00e6pi \u00fearma og a\u00f0rir tengdir efnaskipta\u00fe\u00e6ttir hj\u00e1 b\u00f6rnum og unglingum greind me\u00f0 ge\u00f0raskanir eru sko\u00f0a\u00f0ir \u00ed samanbur\u00f0i vi\u00f0 vi\u00f0mi\u00f0unarh\u00f3pa. Ni\u00f0urst\u00f6\u00f0ur \u00feessa doktorsverkefnis varpa lj\u00f3si \u00e1 fl\u00f3ki\u00f0 samspil milli ofleka \u00fearma (e. hyperpermeability) og tauga\u00feroskaraskana \u00ed b\u00f6rnum.<\/p>\n

Ni\u00f0urst\u00f6\u00f0ur kerfisbundnu yfirlitsranns\u00f3knarinnar og greinasafnagreiningar, \u00e1samt d\u00fdratilraunum, draga fram mikilv\u00e6gi heilleika \u00fearmat\u00e1lmastarfsemi \u00e1samt starfsemi \u00f6rveru-\u00fearma-heila \u00e1ss var\u00f0andi ge\u00f0heilsu. \u00deessar ranns\u00f3knir \u00e1 \u00fearmat\u00e1lma og \u00f6rveru-\u00fearma-heila \u00e1s benda til m\u00f6gulegra n\u00fdst\u00e1rlegra me\u00f0fer\u00f0ar\u00farr\u00e6\u00f0a er tengjast matar\u00e6\u00f0i og l\u00edfsst\u00edl og undirstrika mikilv\u00e6gi frekari ranns\u00f3kna sem geta leitt til einstaklingsmi\u00f0a\u00f0ri me\u00f0fer\u00f0ar\u00edhlutunar \u00ed ge\u00f0l\u00e6kningum. \u00a0\u00a0<\/p>\n

Abstract<\/strong><\/p>\n

Mental disorders, affecting up to a fifth of the global youth population, represent a significant health challenge, with their multifaceted origins involving genetic, environmental, and lifestyle elements. These conditions significantly impact quality of life and are the principal cause of disability among young people. Recent research has increasingly focused on the gut barrier, the innermost layer of the digestive tract that controls two diametrically opposed functions; to facilitate the selective permeability of essential nutrients from the intestinal lumen into the bloodstream and, conversely, to protect against intrusion of detrimental elements present in the lumen by controlled permeability. Central to the barrier function is zonulin, the only human protein known to reversibly regulate intestinal permeability by modulating intercellular tight junctions. The gut barrier function affects the microbiota-gut-brain axis, a communication network connecting the microbiota, the digestive tract, and the nervous system. Research shows that aberrations in this axis may be linked to mental disorders. This thesis aimed to further elucidate the pathophysiology of mental disorders by studying the influence of gut barrier function on the microbiota-gut-brain axis. It focused on understanding the potential causality and underlying mechanisms and pathways, including the impact of food-related stimuli. The overall aim was to investigate the interplay between intestinal permeability and mental disorders, with the following specific objectives: (I) to collate evidence from observational studies on intestinal permeability, evaluating relevant intrinsic biomarkers and exposure to endotoxins in children diagnosed with mental disorders in comparison to healthy controls; (II) to examine the transcriptomic differences in zonulin transgenic mice (Ztm) and study the expression profiles of tight junction genes after an intervention with oral bovine colostrum (BC); (III) to explore the impact of BC intervention on gut microbiota and behavior in wild-type (WT) and Ztm mice; (IV) to develop, compose, and publish a research protocol for a population-based observational longitudinal case-control study that investigates diet, gut microbiota, gut permeability, and related metabolic factors in children and adolescents diagnosed with mental disorders. The principal discoveries described in this thesis underscore the complex interplay between hyperpermeability and neurodevelopmental disorders. The systematic review and meta-analysis, together with the animal experiments, suggest a pivotal role of gut-barrier integrity and microbiota-gut-brain axis in mental health. Overall, these investigations emphasize the potential for novel therapeutic approaches targeting the microbiota-gut-brain axis and highlight the importance of further research to advance our understanding paving the way for effective interventions for mental disorders. Furthermore, the findings increase knowledge and, therefore, possibilities for targeted and more personalized dietary and lifestyle interventions in subgroups.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Birna G. \u00c1sbj\u00f6rnsd\u00f3ttir er f\u00e6dd \u00e1ri\u00f0 1971 \u00ed Reykjav\u00edk. H\u00fan lauk meistaragr\u00e1\u00f0u \u00ed Nutritional Medicine fr\u00e1 University of Surrey \u00ed Bretlandi \u00e1ri\u00f0 2016 og h\u00f3f \u00fe\u00e1 undirb\u00faning \u00e1 ranns\u00f3kninni Matar\u00e6\u00f0i, \u00fearmafl\u00f3ra og ge\u00f0heilsa barna og unglinga \u00e1 Barna- og unglingage\u00f0deild Landsp\u00edtala. \u00c1ri\u00f0 2018 h\u00f3f Birna doktorsn\u00e1m \u00ed heilbrig\u00f0isv\u00edsindum vi\u00f0 Matv\u00e6la- og n\u00e6ringarfr\u00e6\u00f0ideild \u00e1samt L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. H\u00fan hlaut styrki fr\u00e1 Fulbright-stofnuninni, Erasmus+ og stofnun Leifs Eir\u00edkssonar og vann \u00ed kj\u00f6lfari\u00f0 a\u00f0 ranns\u00f3knum s\u00ednum \u00e1 MIBRC ranns\u00f3knasetrinu vi\u00f0 MassGeneral Hospital, Harvard Medical School \u00ed Boston \u00fear sem h\u00fan er gestarannsakandi \u00ed dag. Me\u00f0fram doktorsn\u00e1mi s\u00ednu hefur Birna starfa\u00f0 sem rannsakandi vi\u00f0 F\u00e9lagsfr\u00e6\u00f0i, mannfr\u00e6\u00f0i- og \u00fej\u00f3\u00f0fr\u00e6\u00f0ideild, sinnt kennslu vi\u00f0 \u00fdmsar deildir h\u00e1sk\u00f3lans og haldi\u00f0 fj\u00f6lda erinda og n\u00e1mskei\u00f0a fyrir almenning og fagf\u00f3lk. Birna hefur einnig sinnt n\u00fdsk\u00f6punarverkefnum tengdum s\u00e9rsvi\u00f0um s\u00ednum s\u00ed\u00f0astli\u00f0in \u00e1r. Samb\u00fdlisma\u00f0ur Birnu er Gu\u00f0mundur \u00c1rmann P\u00e9tursson og eiga \u00feau saman tv\u00f6 b\u00f6rn, Emblu L\u00edf og N\u00f3a S\u00e6.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5836,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2024-01-26T09:00:00+00:00","_phd_date_end":"2024-01-26T12:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Gegndr\u00e6pi \u00fearma, \u00f6rveru-\u00fearma-heila \u00e1s, atferli, og ge\u00f0raskanir barna og unglinga. 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