Calanus oil and its constituents as a therapeutic approach to target obesity-induced metabolic distortions

Obesity is one of the leading causes for the development of metabolic disorders, such as insulin resistance and type 2 diabetes. Omega-3 fatty acids, found in seafood and marine oils, are shown to reduce obesity, lower blood lipid levels, change the composition of the gut microbiota and reduce the risk for cardiovascular diseases. The increased demand for seafood and marine oils has put pressure on sustainable fisheries, and the marine crustacean Calanus finmarchicus is an alternative and sustainable source of marine lipids. This oil is unique compared to other marine oils, in the sense that more than 85% of the lipids are wax esters, a lipid class where fatty acids are bound to fatty alcohols. The content of EPA and DHA is relatively low, while it is rich in stearidonic acid and monounsaturated fatty acids. In experimental studies, dietary supplementation with Calanus oil was shown to reduce obesity and obesity-related inflammation, improve glycaemic control, and protect the heart after an ischemic event. In this thesis we examined the effect of Calanus oil on obesity-induced alterations of the gut microbiota and, in addition, we wanted to find out whether the wax ester-derived fatty acids were able to protect cardiac H9c2 cells from lipotoxic stress (induced by exposure to palmitic acid). We found that Calanus oil had the tendency to change the microbial composition in the gut towards a healthier phenotype, although the changes were not statistically significant. The Calanus oil wax ester-derived fatty acids effectively, and in a dose-dependent manner, improved cell viability. This effect was associated with increased fatty acid oxidation, which will alleviate the lipotoxic stress in the cells. We conclude that Calanus oil and/or its wax ester-derived fatty acids can be used as a therapeutic approach to target obesity-induced metabolic disorders.Overvekt er en viktig årsak til utvikling av metabolske forstyrrelser som insulinresistens og type 2 diabetes, og man antar at mer enn 4 millioner mennesker dør hvert år som følge av disse tilstandene. Flere behandlingsregimer har blitt utviklet for å behandle overvekt og medfølgende sykdommer, men få har så langt vist seg å være effektive og/eller trygge. Omega-3 fettsyrer, som fins i sjømat og marine oljer, har vist seg å forbygge overvekt, senke nivået av fettstoffer i blodet, forbedre sammensetningen av bakteriefloraen i tarmen og redusere risikoen for hjerte- og karsykdommer. Det anbefales derfor å spise to porsjoner fisk/uke eller 250 mg/dag av EPA og DHA, to omega-3 fettsyrer som det fins mye av i sjømat. Imidlertid har økt etterspørsel etter omega-3 fettsyrer lagt press på bærekraftig fiskeri, og det er derfor behov for alternative kilder til disse marine fettsyrene. Den marine krepsdyrarten Calanus finmarchicus er en slik alternativ kilde, og Calanusoljen er unik sammenlignet med andre marine oljer ved at mer enn 85% av oljen består av voksestere hvor fettsyrene er bundet til fettalkoholer. Innholdet av EPA og DHA er forholdsvis lavt, men til gjengjeld er Calanusoljen rik på stearidonsyre (en annen omega-3 fettsyre) og langkjedede enumettede fettsyrer. Eksperimentelle studier på dyr har vist at kosttilskudd med Calanusolje reduser overvekt og tilhørende lavgrads-inflammasjon, bedrer glykemisk kontroll og beskytter hjertet etter kunstig påført infarkt. Målet med denne avhandlingen var å følge opp de tidligere resultatene for å videre undersøke det terapeutiske potensialet til Calanusoljen og dens bestanddeler (fettsyrer og fettalkoholer) i forbindelse med metabolske komplikasjoner som følge av overvekt. I artikkel 1 gjennomgikk vi tidligere publiserte vitenskapelige artikler (både eksperimentelle og kliniske) om virkningen av fettsyrer og fettalkoholer på overvekts-indusert lavgrads-inflammasjon. I artikkel 2 fant vi at Calanusoljen i bare liten grad endret den mikrobielle sammensetningen i tarmen (mot en sunnere fenotype) hos overvektige mus. Artikkel 3 beskriver en metode (semi-preparativ fastfase ekstraksjon) som vi utviklet for å isolere fettsyrene og fettalkoholene i voksesterne fra Calanusolje. I artikkel 4 fant vi at disse fettsyrene effektivt og på en dose-avhengig måte forbedret overlevelsen til H9c2 hjerteceller som ble eksponert for høye doser av palmitinsyre (mettet fettsyre). Den beskyttende effekten var assosiert med økt fettsyreoksydasjon, som vil redusere såkalt lipotoksisk stress i cellene. Vi konkluderer derfor at inntak av fettsyrene som fins i Calanusoljens voksestere kan brukes som et målrettet terapeutisk prinsipp for å forebygge metabolske forstyrrelser indusert av overvekt

Obesity-induced alterations in the gut microbiome in female mice fed a high-fat diet are antagonized by dietary supplementation with a novel, wax ester–rich, marine oil

Dietary supplementation with calanus oil, a novel wax ester–rich marine oil, has been shown to reduce adiposity in high-fat diet (HFD)–induced obese mice. Current evidence suggests that obesity and its comorbidities are intrinsically linked with unfavorable changes in the intestinal microbiome. Thus, in line with its antiobesity effect, we hypothesized that dietary supplementation with calanus oil should counteract the obesity-related deleterious changes in the gut microbiota. Seven-week-old female C57bl/6J mice received an HFD for 12 weeks to induce obesity followed by 8-week supplementation with 2% calanus oil. For comparative reasons, another group of mice was treated with exenatide, an antiobesogenic glucagon-like peptide-1 receptor agonist. Mice fed normal chow diet or nonsupplemented HFD for 20 weeks served as lean and obese controls, respectively. 16S rRNA gene sequencing was performed on fecal samples from the colon. HFD increased the abundance of the Lactococcus and Leuconostoc genera relative to normal chow diet, whereas abundances of Allobaculum and Oscillospira were decreased. Supplementation with calanus oil led to an apparent overrepresentation of Lactobacillus and Streptococcus and underrepresentation of Bilophila. Exenatide prevented the HFD-induced increase in Lactococcus and caused a decrease in the abundance of Streptococcus compared to the HFD group. Thus, HFD altered the gut microbiota composition in an unhealthy direction by increasing the abundance of proinflammatory genera while reducing those considered health-promoting. These obesity-induced changes were antagonized by both calanus oil and exenatide

Impact of GLP-1 receptor agonist versus omega-3 fatty acids supplement on obesity-induced alterations of mitochondrial respiration

ObjectiveTo compare administration of the glucagon-like peptide-1 (GLP-1) analogue, exenatide, versus dietary supplementation with the omega-3 fatty acid-rich Calanus oil on obesity-induced alterations in mitochondrial respiration. MethodsSix-week-old female C57BL/6JOlaHSD mice were given high fat diet (HFD, 45% energy from fat) for 12 weeks to induce obesity. Thereafter, they were divided in three groups where one received exenatide (10 mu g/kg/day) via subcutaneously implanted mini-osmotic pumps, a second group received 2% Calanus oil as dietary supplement, while the third group received HFD without any treatment. Animals were sacrificed after 8 weeks of treatment and tissues (skeletal muscle, liver, and white adipose tissue) were collected for measurement of mitochondrial respiratory activity by high-resolution respirometry, using an Oroboros Oxygraph-2k (Oroboros instruments, Innsbruck, Austria). ResultsIt was found that high-fat feeding led to a marked reduction of mitochondrial respiration in adipose tissue during all three states investigated - LEAK, OXPHOS and ETS. This response was to some extent attenuated by exenatide treatment, but not with Calanus oil treatment. High-fat feeding had no major effect on hepatic mitochondrial respiration, but exenatide treatment resulted in a significant increase in the various respiratory states in liver. Mitochondrial respiration in skeletal muscle was not significantly influenced by high-fat diet or any of the treatments. The precise evaluation of mitochondrial respiration considering absolute oxygen flux and ratios to assess flux control efficiency avoided misinterpretation of the results. ConclusionsExenatide increased hepatic mitochondrial respiration in high-fat fed mice, but no clear beneficial effect was observed in skeletal muscle or fat tissue. Calanus oil did not negatively affect respiratory activity in these tissues, which maintains its potential as a dietary supplement, due to its previously reported benefits on cardiac functio

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Seasonal changes in background levels of deuterium and oxygen- 18 prove water drinking by harp seals, which affects the use of the doubly labelled water method

The aim of this study was to monitor seasonal changes in stable isotopes of pool freshwater and harp seal (Phoca groenlandica) body water, and to study whether these potential seasonal changes might bias results obtained using the doubly labelled water (DLW) method when measuring energy expenditure in animals with access to freshwater. Seasonal changes in the background levels of deuterium and oxygen-18 in the body water of four captive harp seals and in the freshwater pool in which they were kept were measured over a time period of 1 year. The seals were offered daily amounts of capelin and kept under a seasonal photoperiod of 69°N. Large seasonal variations of deuterium and oxygen-18 in the pool water were measured, and the isotope abundance in the body water showed similar seasonal changes to the pool water. This shows that the seals were continuously equilibrating with the surrounding water as a result of significant daily water drinking. Variations in background levels of deuterium and oxygen-18 in freshwater sources may be due to seasonal changes in physical processes such as precipitation and evaporation that cause fractionation of isotopes. Rapid and abrupt changes in the background levels of deuterium and oxygen-18 may complicate calculation of energy expenditure by use of the DLW method. It is therefore strongly recommended that analysis of seasonal changes in background levels of isotopes is performed before the DLW method is applied on (free-ranging) animals, and to use a control group in order to correct for changes in background levels

Possible Health Effects of a Wax Ester Rich Marine Oil

The consumption of seafood and the use of fish oil for the production of nutraceuticals and fish feed have increased over the past decades due the high content of long-chain polyunsaturated omega-3 fatty acids. This increase has put pressure on the sustainability of fisheries. One way to overcome the limited supply of fish oil is to harvest lower in the marine food web. Calanus finmarchicus, feeding on phytoplankton, is a small copepod constituting a considerable biomass in the North Atlantic and is a novel source of omega-3 fatty acids. The oil is, however, different from other commercial marine oils in terms of chemistry and, possibly, bioactivity since it contains wax esters. Wax esters are fatty acids that are esterified with alcohols. In addition to the long-chain polyunsaturated omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the oil is also rich in stearidonic acid (SDA), long-chain monounsaturated fatty acids, and the long-chain fatty alcohols eicosenol and docosenol. Recent animal studies have indicated anti-inflammatory and anti-obesogenic actions of this copepod oil beyond that provided by EPA and DHA. This review will discuss potential mechanisms behind these beneficial effects of the oil, focusing on the impact of the various components of the oil. The health effects of EPA and DHA are well recognized, whereas long-chain monounsaturated fatty acids and long-chain fatty alcohols have to a large degree been overlooked in relation to human health. Recently, however the fatty alcohols have received interest as potential targets for improved health via conversion to their corresponding fatty acids. Together, the different lipid components of the oil from C. finmarchicus may have potential as nutraceuticals for reducing obesity and obesity-related metabolic disorders