Replacement of saturated fatty acids (SFA) with monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids (PUFA) impacts risk of atherosclerosis and cardiovascular disease (CVD). However, although dietary fatty acids (DFA) have been established as an important factor related to CVD, their exact mechanisms of action have not been clearly established. One of the possible mechanisms is that DFA convert to fatty acid ethanolamides (FAEs), such as oleoylethanolamide (OEA), palmitoylethanolamide (PEA) and arachidonoylethanolamide (AEA), which are thought to associate with lipid signalling, fat oxidation and appetite control. Hence, the objectives of this thesis were to identify the impact of diets containing corn oil, canola oil, DHA + canola oil and fish oil on plasma and organ levels of FAEs as well as energy metabolism and lipid profiles in Syrian Golden hamsters. Forty-eight hamsters were provided diets containing 6% treatment oil for 30 d before sacrifice. Across all diets, in proximal small intestine and liver, animals fed canola oil showed higher (p<0.05) levels of OEA than corn oil and fish oil fed groups, but no difference compared to those fed DHA +canola oil. In plasma, fish oil fed animals showed higher (p<0.05) OEA and PEA levels and lower (p<0.05) AEA levels compared to all other groups. Feed intakes (g/d), oxygen consumption (ml/g) and body composition of total fat (%) and mass (g) did not differ across groups. However, energy expenditure associated with fat oxidation (%) was higher (p<0.01) in canola oil and DHA + canola oil fed hamsters compared to those consuming corn oil and fish oil. Also, body composition of fish oil fed animals showed a lower (p<0.01) total lean mass (g) compared to other three groups and a lower (p<0.01) total mass (g) compared to DHA + canola oil diets, but no difference compared to animals fed the canola oil diet. None of the treatments had any effect on triglyceride (TG) or C-reactive protein (CRP) levels. The fish oil group showed a higher (p<0.01) plasma total cholesterol (TC) levels than all other three groups. No differences existed between DHA + canola oil and fish oil groups in HDL or Non-HDL levels, but these levels were different (p<0.01) compared to corn oil group and canola oil groups. To conclude, different DFA affect whole body energetics and plasma lipid profiles. Also DFA produced marked shifts in plasma and organ levels of OEA, PEA and AEA. These dietary induced shifts in FAEs may translate into discernable changes in energy expenditure and lipid levels which in turn influence CVD risk.

Replacement of saturated fatty acids (SFA) with monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids (PUFA) impacts risk of atherosclerosis and cardiovascular disease (CVD). However, although dietary fatty acids (DFA) have been established as an important factor related to CVD, their exact mechanisms of action have not been clearly established. One of the possible mechanisms is that DFA convert to fatty acid ethanolamides (FAEs), such as oleoylethanolamide (OEA), palmitoylethanolamide (PEA) and arachidonoylethanolamide (AEA), which are thought to associate with lipid signalling, fat oxidation and appetite control. Hence, the objectives of this thesis were to identify the impact of diets containing corn oil, canola oil, DHA + canola oil and fish oil on plasma and organ levels of FAEs as well as energy metabolism and lipid profiles in Syrian Golden hamsters. Forty-eight hamsters were provided diets containing 6% treatment oil for 30 d before sacrifice. Across all diets, in proximal small intestine and liver, animals fed canola oil showed higher (p<0.05) levels of OEA than corn oil and fish oil fed groups, but no difference compared to those fed DHA +canola oil. In plasma, fish oil fed animals showed higher (p<0.05) OEA and PEA levels and lower (p<0.05) AEA levels compared to all other groups. Feed intakes (g/d), oxygen consumption (ml/g) and body composition of total fat (%) and mass (g) did not differ across groups. However, energy expenditure associated with fat oxidation (%) was higher (p<0.01) in canola oil and DHA + canola oil fed hamsters compared to those consuming corn oil and fish oil. Also, body composition of fish oil fed animals showed a lower (p<0.01) total lean mass (g) compared to other three groups and a lower (p<0.01) total mass (g) compared to DHA + canola oil diets, but no difference compared to animals fed the canola oil diet. None of the treatments had any effect on triglyceride (TG) or C-reactive protein (CRP) levels. The fish oil group showed a higher (p<0.01) plasma total cholesterol (TC) levels than all other three groups. No differences existed between DHA + canola oil and fish oil groups in HDL or Non-HDL levels, but these levels were different (p<0.01) compared to corn oil group and canola oil groups. To conclude, different DFA affect whole body energetics and plasma lipid profiles. Also DFA produced marked shifts in plasma and organ levels of OEA, PEA and AEA. These dietary induced shifts in FAEs may translate into discernable changes in energy expenditure and lipid levels which in turn influence CVD risk.

Background: Cardiovascular disease (CVD) is the leading global cause of death. CVD risk factors are considered intermediaries for the association between dietary fatty acids and CVD. Raised plasma total cholesterol, low density lipoprotein (LDL) cholesterol, raised triglycerides and decreased levels of high density lipoprotein (HDL) cholesterol, as well as reduced fibrinolytic potential (measured as increased clot lysis time) are known risk factors for CVD. Plasminogen activator inhibitor-1 (PAI-1) is a major inhibitor of the fibrinolytic process and an elevated PAI-1 level is therefore considered to be a potential risk factor for CVD. The growing number of controversies around the role that fat intake (more specifically the type of dietary fat) plays in CVD risk, is making it increasingly difficult for consumers and practitioners alike to form conclusions, and make recommendations and decisions regarding fat intake. Knowledge of the intake of individual fatty acids, fatty acid status (as opposed to subgroups of fat such as polyunsaturated fatty acids) and their associations with blood lipids, PAI-1act and fibrinolytic potential is lacking in black South Africans and other populations. Therefore we aimed to investigate dietary fatty acid intake, as well as plasma phospholipid fatty acid status and their associations with blood lipids, PAI-1act and clot lysis time, as a marker for fibrinolytic potential. Methods: Cross-sectional data analysis within the Prospective Rural Urban Epidemiology (PURE) baseline study of apparently healthy black South African men and women (n=1950, 35– 70 years) from rural and urban areas in the North West Province, from whom dietary data were collected. Blood lipid analyses, as well as laboratory analyses of fibrinolysis markers such as PAI-1act and clot lysis time were also performed. Plasma phospholipid fatty acid extraction and isolation were performed on a random subsample (n = 716). Results: The intake of individual fatty acids was significantly higher in urban than rural dwellers. However, the intake of omega-3 polyunsaturated fatty acids was below recommendations in all groups (rural and urban males, and rural and urban females). Total cholesterol and LDL cholesterol were higher in females than in males, with no rural‒urban differences. Intake of alpha-linolenic acid was positively associated with total cholesterol (β=0.143) and triglycerides (β=0.256) in males. The risk of having elevated LDL cholesterol also increased with increased intake of alpha-linolenic acid (OR 1.49, 95% CI 1.04, 2.14). In females, dietary arachidonic acid and eicosapentaenoic acid (EPA) were positively associated with total cholesterol and LDL cholesterol, whereas docosahexaenoic acid (DHA) was negatively associated with total cholesterol and LDL cholesterol. Dietary alpha-linolenic acid was positively correlated with plasma EPA (males r = 0.19, p = 0.002, females r = 0.25, p < 0.001) and DHA (males r = 0.33, p < 0.001, females r = 0.30, p < 0.001). Plasma DHA was positively associated with triglycerides in males (β = 0.410, p< 0.001) and in females (β = 0.379, p< 0.001). PAI-1act was positively associated with clot lysis time, and plasma myristic acid and DHA were positively associated with PAI-1act in females. However, these fatty acids were not associated with clot lysis time. Different types of plasma fatty acids were associated with PAI-1act than with clot lysis time. Plasma alpha-linolenic acid (β = 0.123, P = 0.037), mead acid (β = 0.176, P = 0.019), arachidonic acid (β = 0.253, 0.025) and omega-3 docosapentaenoic acid (omega-3 DPA) (β = 0.224, P = 0.002) were positively associated with clot lysis time, while both myristic acid (β = - 0.130, P = 0.016) and EPA (β = -0.131, P = 0.021) were negatively associated with clot lysis time in male subjects. Plasma oleic acid (C18:1n9) (β = -0.411, P = 0.001) and omega-6 DPA (C22:5n6) (β = -0.285, P = 0.001) were negatively associated with clot lysis time, while dihomogamma- liolenic acid (DGLA) (C20:3n6) were positively associated (β = 0.178, P = 0.001) with clot lysis time in females. Conclusions: These results suggest that specific individual dietary fatty acids might be associated with blood lipids in males differently than in females, irrespective of rural or urban dwelling. It is not known however, if associations would still be present under conditions of greater intake of alpha-linolenic acid. Our results further suggest that a higher percentage of alpha-linolenic acid might be converted to DHA in this population with low intake of essential and long-chain polyunsaturated fatty acids compared to populations with a high intake of these fatty acids. These results suggest that plasma phospholipid fatty acids should not be used in isolation as biomarkers for intake of fat, without taking dietary intake data into consideration also. Associations between fatty acids and clot lysis time might be independent from PAI-1act. The association between mead acid and clot lysis time indicates that clot lysis time might increase with an essential fatty acid deficiency. This may be of particular concern in this population with a documented lower fat intake. Because the study design of this study is crosssectional, it is not able to determine cause-and-effect, and results should therefore be verified with a randomised controlled trial. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2015

Background: Cardiovascular disease (CVD) is the leading global cause of death. CVD risk factors are considered intermediaries for the association between dietary fatty acids and CVD. Raised plasma total cholesterol, low density lipoprotein (LDL) cholesterol, raised triglycerides and decreased levels of high density lipoprotein (HDL) cholesterol, as well as reduced fibrinolytic potential (measured as increased clot lysis time) are known risk factors for CVD. Plasminogen activator inhibitor-1 (PAI-1) is a major inhibitor of the fibrinolytic process and an elevated PAI-1 level is therefore considered to be a potential risk factor for CVD. The growing number of controversies around the role that fat intake (more specifically the type of dietary fat) plays in CVD risk, is making it increasingly difficult for consumers and practitioners alike to form conclusions, and make recommendations and decisions regarding fat intake. Knowledge of the intake of individual fatty acids, fatty acid status (as opposed to subgroups of fat such as polyunsaturated fatty acids) and their associations with blood lipids, PAI-1act and fibrinolytic potential is lacking in black South Africans and other populations. Therefore we aimed to investigate dietary fatty acid intake, as well as plasma phospholipid fatty acid status and their associations with blood lipids, PAI-1act and clot lysis time, as a marker for fibrinolytic potential. Methods: Cross-sectional data analysis within the Prospective Rural Urban Epidemiology (PURE) baseline study of apparently healthy black South African men and women (n=1950, 35– 70 years) from rural and urban areas in the North West Province, from whom dietary data were collected. Blood lipid analyses, as well as laboratory analyses of fibrinolysis markers such as PAI-1act and clot lysis time were also performed. Plasma phospholipid fatty acid extraction and isolation were performed on a random subsample (n = 716). Results: The intake of individual fatty acids was significantly higher in urban than rural dwellers. However, the intake of omega-3 polyunsaturated fatty acids was below recommendations in all groups (rural and urban males, and rural and urban females). Total cholesterol and LDL cholesterol were higher in females than in males, with no rural‒urban differences. Intake of alpha-linolenic acid was positively associated with total cholesterol (β=0.143) and triglycerides (β=0.256) in males. The risk of having elevated LDL cholesterol also increased with increased intake of alpha-linolenic acid (OR 1.49, 95% CI 1.04, 2.14). In females, dietary arachidonic acid and eicosapentaenoic acid (EPA) were positively associated with total cholesterol and LDL cholesterol, whereas docosahexaenoic acid (DHA) was negatively associated with total cholesterol and LDL cholesterol. Dietary alpha-linolenic acid was positively correlated with plasma EPA (males r = 0.19, p = 0.002, females r = 0.25, p < 0.001) and DHA (males r = 0.33, p < 0.001, females r = 0.30, p < 0.001). Plasma DHA was positively associated with triglycerides in males (β = 0.410, p< 0.001) and in females (β = 0.379, p< 0.001). PAI-1act was positively associated with clot lysis time, and plasma myristic acid and DHA were positively associated with PAI-1act in females. However, these fatty acids were not associated with clot lysis time. Different types of plasma fatty acids were associated with PAI-1act than with clot lysis time. Plasma alpha-linolenic acid (β = 0.123, P = 0.037), mead acid (β = 0.176, P = 0.019), arachidonic acid (β = 0.253, 0.025) and omega-3 docosapentaenoic acid (omega-3 DPA) (β = 0.224, P = 0.002) were positively associated with clot lysis time, while both myristic acid (β = - 0.130, P = 0.016) and EPA (β = -0.131, P = 0.021) were negatively associated with clot lysis time in male subjects. Plasma oleic acid (C18:1n9) (β = -0.411, P = 0.001) and omega-6 DPA (C22:5n6) (β = -0.285, P = 0.001) were negatively associated with clot lysis time, while dihomogamma- liolenic acid (DGLA) (C20:3n6) were positively associated (β = 0.178, P = 0.001) with clot lysis time in females. Conclusions: These results suggest that specific individual dietary fatty acids might be associated with blood lipids in males differently than in females, irrespective of rural or urban dwelling. It is not known however, if associations would still be present under conditions of greater intake of alpha-linolenic acid. Our results further suggest that a higher percentage of alpha-linolenic acid might be converted to DHA in this population with low intake of essential and long-chain polyunsaturated fatty acids compared to populations with a high intake of these fatty acids. These results suggest that plasma phospholipid fatty acids should not be used in isolation as biomarkers for intake of fat, without taking dietary intake data into consideration also. Associations between fatty acids and clot lysis time might be independent from PAI-1act. The association between mead acid and clot lysis time indicates that clot lysis time might increase with an essential fatty acid deficiency. This may be of particular concern in this population with a documented lower fat intake. Because the study design of this study is crosssectional, it is not able to determine cause-and-effect, and results should therefore be verified with a randomised controlled trial. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2015

Variations in predator diets is important in ecology to help us understand their top-down effects on the ecosystem. In predator diets, their fatty acid signatures reflect the proportions of prey consumed. Since fatty acid signatures are compositional and often longer than the sample size, a standard MANOVA test is unsuitable. Here, non-parametric MANOVA techniques are developed to test for differences in fatty acid signatures among locations, years, and seasons which infer differences in diets. Simulations show that the test has good power and appropriate type I error rates. The tests developed were applied to data on Greenland Sharks to test for differences in diets between individuals from Cumberland Sound, Canada, versus those from Svalbard, Norway and whether there is a yearly and/or seasonal effect on the diets. Diet compositions were found to vary between the locations, seasons and years, possibly caused by differing prey species distributions, migrations, and climate change.

No description available.

No description available.

no / Human saphenous vein endothelial cells (HSVECs) derived from primary cultures of adult human veins constitute an excellent in vitro model for studying human endothelial metabolism. In this study we report the14C-labelled prostanoid profile of HSVECs under resting and stimulated conditions and the effect of the n-3 polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid on them. Results indicate that HSVECs while under resting conditions produce mainly prostaglandin F2 ¿(PGF2 ¿). After stimulation with calcium ionophore A23187, the cells were found to synthesise PGI2, PGE2and PGF2¿as major products and thromboxane B2and PGD2as minor products. Production of14C-labelled hydroxyeicosatetraenoic acids was not detected. Eicosapentaenoic acid was found to inhibit basal and stimulated prostanoid production whereas docosahexaenoic acid inhibited basal but strongly increased stimulated prostanoid production. These results may offer the basis for further studies aiming to investigate targets for pharmacological intervention in inflammatory conditions.