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dc.contributor.advisorLarsen, Terje S.
dc.contributor.authorSalma, Wahida
dc.date.accessioned2015-01-21T14:23:10Z
dc.date.available2015-01-21T14:23:10Z
dc.date.issued2015-03-04
dc.description.abstractIn this doctoral project we have examined the biological effects of Calanus oil in a mouse model of obesity. Calanus oil is extracted from the marine copepod Calanus finmarchicus and is one of the richest sources of poly-unsaturated fatty acids in nature. C57BL/6J mice were given a high-fat diet (HFD) over a 27 wk period in order to induce obesity, which was reflected in deposition of considerable amounts of fat in the abdominal cavity and liver. In mice receiving HFD supplemented with a small amount of Calanus oil (1.5%) fat accumulation was significantly less, despite no difference in food intake between the groups. Obesity was also associated with increased expression of genes (mRNA level) coding for pro-inflammatory molecules, as well as macrophage infiltration in adipose tissue, indicative of a local (low-grade) inflammation. Moreover, insulin sensitivity was impaired as documented by reduction in glucose tolerance. These obesity-induced alterations were clearly antagonized by dietary Calanus oil, irrespective of whether it was given from the onset of the feeding period or after obesity was established. Another important finding was that wax ester from Calanus oil (i.e. the pure lipid component of the oil, devoid of antioxidants and other bioactive substances) was as effective as crude Calanus oil for obtaining these beneficial effects, and the efficacy of wax ester in producing the anti-obesity effect was even stronger than that of the clinically used ethyl esters of purified EPA and DHA. Finally, the increase in blood pressure which occurred when obese C57BL/6J mice were challenged by angiotensin II infusion was virtually abolished in mice that had been pre-treated with dietary Calanus oil. Dietary Calanus oil also antagonized the reduction in body and organ weights associated with angiotensin II infusion.en
dc.description.doctoraltypedr.philos.en
dc.description.popularabstractIn this doctoral project we have examined the biological effects of Calanus oil in a mouse model of obesity. Calanus oil is extracted from the marine copepod Calanus finmarchicus and is one of the richest sources of poly-unsaturated fatty acids in nature. C57BL/6J mice were given a high-fat diet (HFD) over a 27 wk period in order to induce obesity, which was reflected in deposition of considerable amounts of fat in the abdominal cavity and liver. In mice receiving HFD supplemented with a small amount of Calanus oil (1.5%) fat accumulation was significantly less, despite no difference in food intake between the groups. Obesity was also associated with increased expression of genes (mRNA level) coding for pro-inflammatory molecules, as well as macrophage infiltration in adipose tissue, indicative of a local (low-grade) inflammation. Moreover, insulin sensitivity was impaired as documented by reduction in glucose tolerance. These obesity-induced alterations were clearly antagonized by dietary Calanus oil, irrespective of whether it was given from the onset of the feeding period or after obesity was established. Another important finding was that wax ester from Calanus oil (i.e. the pure lipid component of the oil, devoid of antioxidants and other bioactive substances) was as effective as crude Calanus oil for obtaining these beneficial effects, and the efficacy of wax ester in producing the anti-obesity effect was even stronger than that of the clinically used ethyl esters of purified EPA and DHA. Finally, the increase in blood pressure which occurred when obese C57BL/6J mice were challenged by angiotensin II infusion was virtually abolished in mice that had been pre-treated with dietary Calanus oil. Dietary Calanus oil also antagonized the reduction in body and organ weights associated with angiotensin II infusion. Collectively, these findings support the notion that low-grade inflammation in adipose tissue is the link between obesity and insulin resistance, and that reduction of visceral and ectopic fat mass by Calanus oil supplementation is an obvious strategy for targeting the inflammatory network. The capacity of dietary Calanus oil to antagonize angiotensin II-induced hypertension should also be ascribed to the anti-inflammatory action of the oil, both in the adipose tissue and vasculature.  en
dc.description.sponsorshipNorwegian Heart Foundation as well as partially from Calanus AS, Norwayen
dc.descriptionThe papers of this thesis are not available in Munin:<br> I. Höper, Anje Christina; Salma, Wahida; Khalid, Ahmed Murtaz; Hafstad, Anne Dragøy; Sollie, Selene Julie; Raa, Jan; Larsen, Terje; Aasum, Ellen. Oil from the marine zooplankton Calanus finmarchicus improves the cardiometabolic phenotype of diet-induced obese mice. British Journal of Nutrition 2013; Volum 110. s. 1145 2186 - 2193. Available at <a href=http://dx.doi.org/10.1017/S0007114513001839>http://dx.doi.org/10.1017/S0007114513001839</a><br> II. Höper, Anje Christina; Salma, Wahida; Sollie, Selene Julie; Hafstad, Anne Dragøy; Lund, Jim; Khalid, Ahmed Murtaz; Raa, Jan; Aasum, Ellen; Larsen, Terje. Wax esters from the marine copepod calanus finmarchicus reduce diet-induced obesity and obesity-related metabolic disorders in mice. Journal of Nutrition 2014; Volum 144 (2), s.164 – 169. Available at <a href=http://dx.doi.org/10.3945/jn.113.182501>http://dx.doi.org/10.3945/jn.113.182501</a><br> III. Salma W, Franekova V, Lund T, Höper AC, Ludvigsen S, Lund J, Aasum E, Ytrehus K, Belke DD, Larsen TS. Dietary Calanus oil antagonizes angiotensin II-induced hypertension and tissue wasting in obese mice. Manuscript submitted in American journal of Physiology. (Manuscript).en
dc.identifier.urihttps://hdl.handle.net/10037/7040
dc.identifier.urnURN:NBN:no-uit_munin_6623
dc.language.isoengen
dc.publisherUiT The Arctic University of Norwayen
dc.publisherUiT Norges arktiske universiteten
dc.rights.accessRightsopenAccess
dc.rights.holderCopyright 2015 The Author(s)
dc.subject.courseIDDOKTOR-003en
dc.subjectAbdominal obesity, inflammation, n-3 PUFA, Insulin resistanceen
dc.subjectHypertension, calanus oilen
dc.titleAnti-Obesity and Anti-Hypertensive Action of Calanus Oilen
dc.typeDoctoral thesisen
dc.typeDoktorgradsavhandlingen


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