ORCID Profile
0000-0003-0252-8039
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biochemistry and Cell Biology | Analytical Spectrometry | Biochemistry And Cell Biology Not Elsewhere Classified | Analytical Biochemistry | Medical Biochemistry: Lipids | Microbiology Not Elsewhere Classified | Ecology And Evolution Not Elsewhere Classified |
ANZSRC Socio-Economic Objective (SEO)
Cardiovascular system and diseases | Endocrine organs and diseases (incl. diabetes) | Biological sciences | Scientific instrumentation | Other
Related Links
Publications
FISH AND THE HEART
Publisher: Elsevier BV
Date: 12-1989
Investigating the impact of a research-based integrated curriculum on self-perceived research experiences of medical students in community placements: A pre- and post-test analysis of three student cohorts
Publisher: Springer Science and Business Media LLC
Date: 05-08-2014
A review and evaluation of study design considerations for omega-3 fatty acid supplementation trials in physically trained participants
Publisher: Cambridge University Press (CUP)
Date: 09-01-2023
DOI: 10.1017/S095442242300001X
Abstract: Long-chain omega-3 polyunsaturated fatty acid (LC n -3 PUFA) supplements, rich in eicosapentaenoic acid and/or docosahexaenoic acid, are increasingly being recommended within athletic institutions. However, the wide range of doses, durations and study designs implemented across trials makes it difficult to provide clear recommendations. The importance of study design characteristics in LC n -3 PUFA trials has been detailed in cardiovascular disease research, and these considerations may guide LC n -3 PUFA study design in healthy cohorts. This systematic review examined the quality of studies and study design considerations used in evaluating the evidence for LC n -3 PUFA improving performance in physically trained adults. SCOPUS, PubMed and Web of Science electronic databases were searched to identify studies that supplemented LC n -3 PUFA in physically trained participants. Forty-six ( n = 46) studies met inclusion. Most studies used a randomised control design. Risk of bias, assessed using the design-appropriate Cochrane Collaboration tool, revealed that studies had a predominant judgment of ‘some concerns’, ‘high risk’ or ‘moderate risk’ in randomised controlled, randomised crossover or non-randomised studies, respectively. A custom five-point quality assessment scale demonstrated that no study satisfied all recommendations for LC n -3 PUFA study design. This review has highlighted that the disparate range of study designs is likely contributing to the inconclusive state of outcomes pertaining to LC n -3 PUFA as a potential ergogenic aid. Further research must adequately account for the specific LC n -3 PUFA study design considerations, underpinned by a clear hypothesis, to achieve evidence-based dose, duration and composition recommendations for physically trained in iduals.
Effect of ischaemia and role of eicosanoids in release of atrial natriuretic factor from rat heart
Publisher: Oxford University Press (OUP)
Date: 09-1993
Abstract: The aim was to investigate (1) the relationship between atrial natriuretic factor (ANF) release and the extent of ischaemia-hypoxia, and (2) the potential role of eicosanoids in ANF release during global ischaemia, particularly the cyclo-oxygenase derivatives (prostaglandins) and the lipoxygenase derivatives (leukotrienes). Using an isolated perfused, spontaneously beating rat heart, global ischaemia was achieved by the reduction of perfusion flow rate relative to basal flow rate. ANF was measured by radioimmunoassay. A decrease in perfusion flow rate by 75-80% to a final value of 2-2.5 ml.min-1.g-1 heart (n = 6) caused a gradual but sustained increase of ANF release which reached a plateau after 12 min, attaining a peak value of 89.9 (SEM 26.6)% over baseline. A decrease in perfusion flow rate by 55-60% (n = 5) also resulted in an increased ANF secretion, with a peak of 125.6(23.2)% over baseline at 14 min. A decrease in perfusion flow rate by 25-30% to a final value of 5-6.75 ml.min-1.g-1 heart (n = 4) showed no change in ANF release. The mean basal value of ANF release was 8.23(2.39) ng.min-1.g-1 heart (n = 26). In a separate series of experiments using a reduction of 55-60% in perfusion flow rate but with the addition to the perfusion medium of the specific cyclo-oxygenase inhibitor meclofenamate 10 microM (n = 5) or the lipoxygenase inhibitor nordihydroguaiaretic acid 10 microM (n = 5), no increase in ANF release occurred during the period of global ischaemia. Neither inhibitor affected ANF release during basal perfusion rates (7-9 ml.min-1.g-1 heart). ANF released in response to global ischaemia is likely to be mediated by prostanoids generated via the cyclo-oxygenase pathway and leukotrienes generated via the lipoxygenase pathway. Both pathways may provide important paracrine/autacoid regulatory roles for the protection of the heart during ischaemia by stimulating ANF release, with the subsequent beneficial effects of the peptide on peripheral tissues, ultimately leading to a reduction in load on the heart.
Dietary fish oil is antihypertrophic but does not enhance postischemic myocardial function in female mice
Publisher: American Physiological Society
Date: 04-2009
DOI: 10.1152/AJPHEART.01151.2008
Abstract: Clinically and experimentally, a case for omega-3 polyunsaturated fatty acid (PUFA) cardioprotection in females has not been clearly established. The goal of this study was to investigate whether dietary omega-3 PUFA supplementation could provide ischemic protection in female mice with an underlying genetic predisposition to cardiac hypertrophy. Mature female transgenic mice (TG) with cardiac-specific overexpression of angiotensinogen that develop normotensive cardiac hypertrophy and littermate wild-type (WT) mice were fed a fish oil-derived diet (FO) or PUFA-matched control diet (CTR) for 4 wk. Myocardial membrane lipids, ex vivo cardiac performance (intraventricular balloon) after global no-flow ischemia and reperfusion (15/30 min), and reperfusion arrhythmia incidence were assessed. FO diet suppressed cardiac growth by 5% and 10% in WT and TG, respectively ( P 0.001). The extent of mechanical recovery [rate-pressure product (RPP) = beats/min × mmHg] of FO-fed WT and TG hearts was similar (50 ± 7% vs. 45 ± 12%, 30 min reperfusion), and this was not significantly different from CTR-fed WT or TG. To evaluate whether systemic estrogen was masking a protective effect of the FO diet, the responses of ovariectomized (OVX) WT and TG mice to FO dietary intervention were assessed. The extent of mechanical recovery of FO-fed OVX WT and TG (RPP, 50 ± 4% vs. 64 ± 8%) was not enhanced compared with CTR-fed mice (RPP, 60 ± 11% vs. 80 ± 8%, P = 0.335). Dietary FO did not suppress the incidence of reperfusion arrhythmias in WT or TG hearts (ovary-intact mice or OVX). Our findings indicate a lack of cardioprotective effect of dietary FO in females, determined by assessment of mechanical and arrhythmic activity postischemia in a murine ex vivo heart model.
Long-term saturated fat supplementation in the rat causes an increase in PGI2 TXB2 ratio of platelet and vessel wall compared to n - 3 and n - 6 dietary fatty acids
Publisher: Elsevier BV
Date: 08-1987
A daily dose of fish oil increased the omega‐3 index in older adults and reduced their heart rate during a walking activity: A pilot study
Publisher: Wiley
Date: 06-2021
DOI: 10.1111/NBU.12497
Abstract: This pilot study sought to determine whether a low, supplemental intake of fish oil would raise the Omega‐3 Index (O3I) and improve physical fitness in healthy older adults. Participants (70 ± 3 years) were randomised to 2 g/day of either sunola oil (control n = 8, 62.5% female) (1700 mg/day oleic acid) or docosahexaenoic acid (DHA)‐rich fish oil (FO n = 9, 55.6% female) [delivering 560 mg/day DHA and 140 mg/day eicosapentaenoic acid (EPA)] for 16 weeks. The O3I, physical fitness, 400 m walking speed and heart rate (HR) parameters were assessed. O3I was increased after FO (mean ± SD, control: pre 6.1 ± 0.8, post 5.9 ± 0.6 FO: pre 6.0 ± 0.6, post 8.3 ± 1.2 p 0.05). Mean lowest overnight HR (control: pre 58 ± 6, post 58 ± 6 FO: pre 55 ± 6, post 52 ± 6 bpm, p 0.05) and mean HR during fast walking (control: pre 120 ± 6, post 124 ± 7 FO: pre 122 ± 6, post 115 ± 6 bpm, p 0.01) were reduced in the FO group without a change in walking speed (control: pre 1.55 ± 0.17, post 1.58 ± 0.20 FO: pre 1.59 ± 0.15, post 1.59 ± 0.18 m/s), HR variability or physical fitness. The changes in lowest resting HR and fast walking HR significantly correlated (inversely) with the changes in O3I. This nutritional approach of providing dietary achievable DHA offers a potential opportunity to reduce cardiovascular strain during physical activity in the older adult.
Role of fat amount and type in ameliorating diet‐induced obesity: insights at the level of hypothalamic arcuate nucleus leptin receptor, neuropeptide Y and pro‐opiomelanocortin mRNA expression
Publisher: Wiley
Date: 15-12-2002
DOI: 10.1111/J.1463-1326.2004.00312.X
Abstract: Dietary fatty acid profile, independent of caloric percent of fat, is a major regulator of body adiposity. This study examined the effects of dietary fat amount and types on fat storage and hypothalamic gene expression in the mouse model of chronic diet-induced obesity. The dietary interventions were in twofold: (1) the obesity was induced by a 13-week obesogenic fat diet compared with a low-fat (LF) diet, and (2) the reversibility was tested by using high n-3 polyunsaturated fat (PUFA) and LF diets. Fifty-four C57Bl/6 mice were fed a high-fat (59% in kcal) diet for 13 weeks and then classified as diet-induced obese (DIO) or diet-resistant (DR) mice according to upper and lower tertiles of body weight gain. The DIO mice were then sub ided into three groups for a 6-week secondary dietary intervention. Two of the groups were switched to either a high n-3 PUFA (DIO-n3) or a low-fat (10% in kcal, DIO-LF) diet, whereas the third (controls) and DR mice continued on the initial high-fat diet. Food efficiency was calculated as weekly body weight gain per gram of food intake. After switching the DIO mice to the n-3 PUFA or LF diet, their body weights were reduced to the level of the DR and LF mice. The food efficiencies were, from the highest to lowest, in the order: DIO>LF>DR>DIO-LF>DIO-n3. Using quantitative in situ hybridization, we found that the DIO mice had higher levels of leptin receptor (LR, +290%, p<0.005) and neuropeptide Y (NPY, +25%, p<0.05) mRNA expression in the hypothalamic arcuate nucleus (Arc) than the DR mice, whereas the level of pro-opiomelanocortin (POMC) mRNA expression was significantly reduced (-45%, p<0.01). All effects that were essentially returned to DR levels by the change to the n-3 PUFA diet and, with the exception of a failure to normalize Arc NPY mRNA levels, by the change to LF diet. Taken together, the present results show that both change in level and quality of dietary fat can potently alter hypothalamic neuropeptide expression and result in effective amelioration of diet-induced obesity. Interestingly, the n-3 PUFA diet when fed to already obese mice produced a pattern of hypothalamic gene expression similar to that in obesity resistant (DR) mice. It remains to be determined if the effects of n-3 fatty acids on brain neuropeptide gene expression are direct or indirect.
Myocardial function, ischaemia and n-3 polyunsaturated fatty acids: a membrane basis
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2007
Health Literacy amongst Health Professional University Students: A Study Using the Health Literacy Questionnaire
Publisher: MDPI AG
Date: 16-05-2017
Medical Student Research during a Longitudinal Community-Based Placement Can Provide Opportunities for Learning about Public Health
Publisher: MDPI AG
Date: 23-04-2018
Dietary fish oil preserves cardiac function in the hypertrophied rat heart
Publisher: Cambridge University Press (CUP)
Date: 09-11-2012
DOI: 10.1017/S0007114511005915
Abstract: Regular fish or fish oil intake is associated with a low incidence of heart failure clinically, and fish oil-induced reduction in cardiac remodelling seen in hypertrophy models may contribute. We investigated whether improved cardiac energy efficiency in non-hypertrophied hearts translates into attenuation of cardiac dysfunction in hypertrophied hearts. Male Wistar rats ( n 33) at 8 weeks of age were sham-operated or subjected to abdominal aortic stenosis to produce pressure-overload cardiac hypertrophy. Starting 3 weeks post-operatively to follow initiation of hypertrophy, rats were fed a diet containing 10 % olive oil (control) or 5 % fish oil (ROPUFA® 30 (17 % EPA, 10 % DHA))+5 % olive oil (FO diet). At 15 weeks post-operatively, ventricular haemodynamics and oxygen consumption were evaluated in the blood-perfused, isolated working heart. Resting and maximally stimulated cardiac output and external work were % depressed in hypertrophied control hearts but this was prevented by FO feeding, without attenuating hypertrophy. Cardiac energy efficiency was lower in hypertrophy, but greater in FO hearts for any given cardiac mass. Coronary blood flow, restricted in hypertrophied control hearts, increased with increasing work in hypertrophied FO hearts, revealing a significant coronary vasodilator reserve. Pronounced cardiac dysfunction in hypertrophied hearts across low and high workloads, indicative of heart failure, was attenuated by FO feeding in association with membrane incorporation of n -3 PUFA, principally DHA. Dietary fish oil may offer a new approach to balancing the high oxygen demand and haemodynamic requirements of the failing hypertrophied heart independently of attenuating hypertrophy.
Dietary fish oil delays hypoxic skeletal muscle fatigue and enhances caffeine-stimulated contractile recovery in the rat in vivo hindlimb
Publisher: Canadian Science Publishing
Date: 06-2017
Abstract: Oxygen efficiency influences skeletal muscle contractile function during physiological hypoxia. Dietary fish oil, providing docosahexaenoic acid (DHA), reduces the oxygen cost of muscle contraction. This study used an autologous perfused rat hindlimb model to examine the effects of a fish oil diet on skeletal muscle fatigue during an acute hypoxic challenge. Male Wistar rats were fed a diet rich in saturated fat (SF), long-chain (LC) n-6 polyunsaturated fatty acids (n-6 PUFA), or LC n-3 PUFA DHA from fish oil (FO) (8 weeks). During anaesthetised and ventilated conditions (normoxia 21% O 2 (SaO 2 –98%) and hypoxia 14% O 2 (SaO 2 –89%)) the hindlimb was perfused at a constant flow and the gastrocnemius–plantaris–soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6–12V, 0.05 ms) to established fatigue. Caffeine (2.5, 5, 10 mM) was supplied to the contracting muscle bundle via the arterial cannula to assess force recovery. Hypoxia, independent of diet, attenuated maximal twitch tension (normoxia: 82 ± 8 hypoxia: 41 ± 2 g·g −1 tissue w.w.). However, rats fed FO sustained higher peak twitch tension compared with the SF and n-6 PUFA groups (P 0.05), and the time to decline to 50% of maximum twitch tension was extended (SF: 546 ± 58 n-6 PUFA: 522 ± 58 FO: 792 ± 96 s P 0.05). In addition, caffeine-stimulated skeletal muscle contractile recovery was enhanced in the FO-fed animals (SF: 41 ± 3 n-6 PUFA: 40 ± 4 FO: 52 ± 7% recovery P 0.05). These results support a physiological role of DHA in skeletal muscle membranes when exposed to low-oxygen stress that is consistent with the attenuation of muscle fatigue under physiologically normoxic conditions.
Graduating work-ready professionals: Research competency as a critical curriculum component
Publisher: James Nicholas Publishers
Date: 06-2017
DOI: 10.7459/CT/32.1.03
Intrinsic heart rate recovery after dynamic exercise is improved with an increased omega-3 index in healthy males
Publisher: Cambridge University Press (CUP)
Date: 30-10-2014
DOI: 10.1017/S0007114514003146
Abstract: Dietary fish consumption contributes to a reduced risk of cardiac mortality. In the present study, the effect of low-dose fish oil (FO) supplementation on heart rate (HR) response to intense exercise and recovery was investigated in physically fit males. The subjects ( n 26) were supplemented (double-blind, parallel design) with (2 × 1 g/d) soya bean oil (control) or tuna FO providing the long-chain n -3 PUFA DHA (560 mg) and EPA (140 mg). Erythrocyte omega-3 index (%EPA+DHA), HR, HR variability and HR recovery were analysed during rest, intense exercise and recovery at baseline and after 8 weeks of supplementation. The mean erythrocyte omega-3 index, which did not differ between the groups at baseline (control 4·2 ( sem 0·2), n 13 FO 4·7 ( sem 0·2), n 13), remained unchanged in the control group (3·9 ( sem 0·2)), but increased in the FO group (6·3 ( sem 0·3) P 0·01). The mean HR during supine resting conditions (control 56 ( sem 10) FO 59 ( sem 9)) was not affected by FO supplementation. Poincaré analysis of HR variability at rest exhibited a decreasing trend in parasympathetic activity in the FO group (SD1 (standard deviation of points perpendicular to the axis of line of identity)/SD2 (standard deviation of points along the axis of line of identity): control 0·02 ( sem 0·01) FO − 0·05 ( sem 0·02) P = 0·18). Peak HR was not affected by supplementation. However, during submaximal exercise over 5 min, fewer total heart beats were recorded in the FO group ( − 22 ( sem 6) ( = − 4·5 beats/min)), but not in the control group (+1 ( sem 4)) ( P 0·05). Supine HR recovery (half-time) after cycling was significantly faster after FO supplementation (control − 0·4 ( sem 1·2) s FO − 8·0 ( sem 1·7) s P 0·05). A low intake of FO increased the omega-3 index and reduced the mean exercise HR and improved HR recovery without compromising the peak HR. A direct influence of DHA via reductions in the cardiac intrinsic beat rate was balanced by a reciprocal decrease in vagal tone.
Differential effects of dietary fish oil on myocardial prostaglandin I2 and thromboxane A2 production
Publisher: American Physiological Society
Date: 02-1991
DOI: 10.1152/AJPHEART.1991.260.2.H379
Abstract: Marmoset monkeys (Callithrix jacchus) were maintained for 24 mo on a standard primate diet [reference (Ref) diet] or this diet supplemented (8% wt/wt) with either sheep fat (SF), sunflower seed oil (SSO), or tuna fish oil (TFO). The polyunsaturated fatty acids (PUFA) of myocardial phospholipids demonstrated significant alterations as a result of the dietary (n-3) or (n-6) lipid supplementation. The reduction (P less than 0.05) in prostaglandin (PG) I2 in PUFA diet-fed groups (SSO, 113.8 +/- 7.8 TFO, 87.9 +/- 8.2 compared with Ref, 153.9 +/- 7.4 pg/mg dry wt) seems to be due to the rate limitation of the endogenous substrate, because the addition of exogenous arachidonic acid (AA) has obliterated the dietary difference. However, AA did not increase the basal PGI2 production in the Ref or SF dietary groups, which differed from that for thromboxane (Tx) A2 where 2- to 5-fold stimulation was observed. It is suggested that there exists a preferential channeling mechanism to direct AA derived from phospholipase hydrolysis of membrane phospholipids toward PGI2 synthesis. Conversely, the bulk of the AA for TxA2 biosynthesis appears to be supplied by a cytosolic nonesterified fatty acid pool. The effective replacement of AA of this pool and a specific inhibition of TxA2 synthetase enzyme complex by the (n-3) PUFA of fish oil are offered as likely mechanisms for the greater inhibition of TxA2 compared with PGI2 production observed in the present and previous studies. The present data on myocardial eicosanoids correlate well with the beneficial qualities of (n-3) and (n-6) dietary PUFA on cardiac function that we have reported previously.
DHA-rich Fish Oil Increases the Omega-3 Index and Lowers the Oxygen Cost of Physiologically Stressful Cycling in Trained Individuals
Publisher: Human Kinetics
Date: 08-2017
Abstract: Dietary fish oil, providing docosahexaenoic acid (DHA) modulates oxygen consumption and fatigue in animal models. However, in humans predominately supplemented with high eicosapentaenoic acid (EPA), there is no evidence of endurance performance enhancement. Therefore, this study examined if DHA-rich fish oil could improve repeated bouts of physiologically stressful cycling and a subsequent time trial in a state of fatigue. Twenty-six trained males took part in a double-blind study and were supplemented with either 2 × 1g/day soy oil, Control) or DHA-rich tuna fish oil (Nu-Mega) (FO) (560mg DHA / 140mg eicosapentaenoic acid (EPA), for 8 weeks. Maximal cycling power (3 × 6s), isometric quadriceps strength (MVC), Wingate cycling protocol (6 × 30s) and a 5min cycling time-trial were assessed at baseline and eight weeks. The Omega-3 Index was not different at baseline (Control: 4.2 ± 0.2 FO: 4.7 ± 0.2%) and increased in the FO group after eight weeks (Control: 3.9 ± 0.2 FO: 6.3 ± 0.3%, p .01). There was no effect of DHA-rich fish oil on power output of maximal 6s cycle sprinting (Control: Pre 1100 ± 49 Post 1067 ± 51 FO: Pre 1070 ± 46 Post 1042 ± 46W), during 5min time trail (Control: Pre 267 ± 19 Post 278 ± 20 FO: Pre 253 ± 16 Post 265 ± 16 W) or maximal voluntary contraction force (Control: Pre 273 ± 19 Post 251 ± 19 FO: Pre 287 ± 17 Post 283 ± 16 Nm). Nevertheless, relative oxygen consumption was reduced the FO group during the cycling time trial (Control: -23 ± 26 FO: -154 ± 59ml O2/min/100W p .05) suggesting improved economy of cycling. We conclude that DHA-rich fish oil, successful at elevating the Omega-3 Index, and reflective of skeletal muscle membrane incorporation, can modulate oxygen consumption during intense exercise.
Cardiac arrhythmia in rats in response to dietary n-3 fatty acids from red meat, fish oil and canola oil
Publisher: Elsevier BV
Date: 12-1993
Radionuclide angiographic study of the influence of dietary lipid supplements on cardiac function in the marmoset (Callithrix jacchus)
Publisher: Oxford University Press (OUP)
Date: 05-1987
DOI: 10.1093/CVR/21.5.369
Abstract: Radionuclide angiography was used to examine the influence of dietary fat on cardiac function in the common marmoset monkey (Callithrix jacchus jacchus) under barbiturate anaesthesia. Animals were fed for 6-8 months with a low fat (4.5%) reference diet or the same diet supplemented (12%) with sunflower seed oil or sheep fat. Although there was a tendency towards increased heart rate, left ventricular ejection fraction, peak ejection rate, and peak filling rate in both fat supplemented groups, significant increases in heart rate (+50%), peak ejection rate (+71%), and peak filling rate (+84%) were found with sheep fat supplementation, whereas only the vegetable oil supplement produced a significant improvement in left ventricular ejection fraction (+23%). There were no differences in resting blood pressure, and the main consequence of dietary fat supplementation was a major increase in apparent cardiac oxygen consumption (+58%) with the sheet fat diet, as determined by the pressure-rate index. Infusion of isoprenaline hydrochloride (0.2 microgram.kg-1.min-1) increased all indices of cardiac function towards common maxima. There were no differences in either the depth or duration of anaesthesia between dietary groups. It therefore is unlikely that this contributed to any of the observed dietary induced differences in cardiac function. It is suggested that dietary saturated animal fat increased cardiac work and oxygen consumption at rest to the extent that functional reserve to respond to stress was significantly diminished. Feeding a linoleic acid rich polyunsaturated vegetable oil supplement was, however, accompanied by evidence of some improvement in left ventricular ejection fraction.
Differences between in vivo and in vitro production of eicosanoids following long-term dietary fish oil supplementation in the rat
Publisher: Elsevier BV
Date: 03-1991
Cardiac contractile dysfunction, during and following ischaemia, is attenuated by low-dose dietary fish oil in rats
Publisher: Springer Science and Business Media LLC
Date: 13-06-2021
Cardiac Membrane Fatty Acid Composition Modulates Myocardial Oxygen Consumption and Postischemic Recovery of Contractile Function
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 14-05-2002
DOI: 10.1161/01.CIR.0000015604.88808.74
Abstract: Background — Regular fish consumption is associated with low cardiovascular disease morbidity and mortality. Fish oils modify cardiac membrane phospholipid fatty acid composition with potent antiarrhythmic effects. We tested the effects of dietary fish oil on ventricular hemodynamics and myocardial oxygen consumption (MVO 2 ). Methods and Results — Male Wistar rats were fed for 16 weeks on a reference diet rich in n -6 polyunsaturated fatty acids (PUFA), a diet rich in saturated animal fat (SAT), or a diet rich in n -3 PUFA from fish oil. Isolated working hearts were perfused with porcine erythrocytes (40% hematocrit) at 75 mm Hg afterload with variable preload (5 to 20 mm Hg) or with low coronary flow ischemia with maintained afterload, preload, and heart rate, then reperfused. MVO 2 was low and coronary perfusion reserve high in n -3 PUFA hearts, and cardiac output increased with workload. The n -3 PUFA reduced ischemic markers—acidosis, K + , lactate, and creatine kinase—and increased contractile recovery during reperfusion. SAT hearts had high MVO 2 , low coronary perfusion reserve, and poor contractile function and recovery. Dietary differences in MVO 2 were abolished by KCl arrest (basal metabolism) or ruthenium red (3.4 μmol/L) but not by ryanodine (1 nmol/L). Fish oil or ryanodine, but not ruthenium red, prevented ventricular fibrillation in reperfusion. Conclusions — Dietary fish oil directly influenced heart function and improved cardiac responses to ischemia and reperfusion. The n -3 PUFA reduced oxygen consumption at any given work output and increased postischemic recovery. Thus, direct effects on myocardial function may contribute to the altered cardiovascular disease profile associated with fish consumption.
Dietary omega-6 fatty acid replacement selectively impairs cardiac functional recovery after ischemia in female (but not male) rats.
Publisher: American Physiological Society
Date: 09-2016
DOI: 10.1152/AJPHEART.00690.2015
Abstract: A definitive understanding of the role of dietary lipids in determining cardioprotection (or cardiodetriment) has been elusive. Randomized trial findings have been variable and sex specificity of dietary interventions has not been determined. In this investigation the sex-selective cardiac functional effects of three diets enriched by omega-3 or omega-6 polyunsaturated fatty acids (PUFA) or enriched to an equivalent extent in saturated fatty acid components were examined in rats after an 8-wk treatment period. In females the myocardial membrane omega-6:omega-3 PUFA ratio was twofold higher than males in the omega-6 diet replacement group. In diets specified to be high in omega-3 PUFA or in saturated fat, this sex difference was not apparent. Isolated cardiomyocyte and heart Langendorff perfusion experiments were performed, and molecular measures of cell viability were assessed. Under basal conditions the contractile performance of omega-6 fed female cardiomyocytes and hearts was reduced compared with males. Omega-6 fed females exhibited impaired systolic resilience after ischemic insult. This response was associated with increased postischemia necrotic cell damage evaluated by coronary lactate dehydrogenase during reperfusion in omega-6 fed females. Cardiac and myocyte functional parameters were not different between omega-3 and saturated fat dietary groups and within these groups there were no discernible sex differences. Our data provide evidence at both the cardiac and cardiomyocyte levels that dietary saturated fatty acid intake replacement with an omega-6 (but not omega-3) enriched diet has selective adverse cardiac effect in females. This finding has potential relevance in relation to women, cardiac risk, and dietary management.
Long-chain n-3 DHA reduces the extent of skeletal muscle fatigue in the rat in vivo hindlimb model
Publisher: Cambridge University Press (CUP)
Date: 11-11-2013
DOI: 10.1017/S0007114513003449
Abstract: Dietary fish oil modifies skeletal muscle membrane fatty acid composition and oxygen efficiency similar to changes in the myocardium. Oxygen efficiency is a key determinant of sustained force in mammalian skeletal muscle. Therefore, in the present study, we tested the effects of a fish-oil diet on skeletal muscle fatigue under the stress of contraction using the rat in vivo autologous perfused hindlimb model. For 8 weeks, male Wistar rats were fed a diet rich in saturated fat (SF), a diet rich in n -6 PUFA or a diet rich in long-chain (LC) n -3 PUFA DHA derived from fish oil. In anaesthetised, mechanically ventilated rats, with their hindlimbs perfused with arterial blood at a constant flow, the gastrocnemius–plantaris–soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6–12 V, 0·05 ms) to contract repetitively for 30 min. Rats fed the n -3 PUFA diet developed higher maximum twitch tension than those fed the SF and n -6 PUFA diets ( P 0·05) and sustained twitch tension through more repetitions before the tension declined to 50 % of the maximum twitch tension ( P 0·05). The n -3 PUFA group used less oxygen for tension developed and produced higher venous lactate concentrations with no difference in glycogen utilisation compared with the SF and n -6 PUFA groups. These results further support that incorporation of DHA into skeletal muscle membranes increases the efficiency of oxygen use over a range of contractile force and this is expressed as a higher sustained force and prolonged time to fatigue.
The cardiovascular protective role of docosahexaenoic acid
Publisher: Elsevier BV
Date: 04-1996
DOI: 10.1016/0014-2999(95)00861-6
Abstract: Dietary fish oils rich in n-3 polyunsaturated fatty acids can modulate a erse range of factors contributing to cardiovascular disease. This study examined the relative roles of eicosapentaenoic acid (20:5 n-3 EPA) and docosahexaenoic acid (22:6 n-3 DHA) which are the principal n-3 polyunsaturated fatty acids regarded as candidates for cardioprotective actions. At low dietary intakes (0.4-1.1% of energy (%en)), docosahexaenoic acid but not eicosapentaenoic acid inhibited ischaemia-induced cardiac arrhythmias. At intakes of 3.9-10.0%en, docosahexaenoic acid was more effective than eicosapentaenoic acid at retarding hypertension development in spontaneously hypertensive rats (SHR) and inhibiting thromboxane-like vasoconstrictor responses in aortas from SHR. In stroke-prone SHR with established hypertension, docosahexaenoic acid (3.9-10.0%en) retarded the development of salt-loading induced proteinuria but eicosapentaenoic acid alone was ineffective. The results demonstrate that purified n-3 polyunsaturated fatty acids mimic the cardiovascular actions of fish oils and imply that docosahexaenoic acid may be the principal active component conferring cardiovascular protection.
A Small Cohort Omega-3 PUFA Supplement Study: Implications of Stratifying According to Lipid Membrane Incorporation in Cardiac Surgical Patients
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.HLC.2016.12.007
Abstract: Epidemiological studies and randomised clinical trials (RCTs) report disparate findings in relation to omega-3 polyunsaturated fatty acids (n-3 PUFA) benefit for cardiac patients. With RCTs interpretation is potentially confounded by background n-3 PUFA intake. The goal of this pilot, small cohort, pre-surgical supplementation study was to evaluate postoperative atrial fibrillation (AF) and cardiac molecular expression profiles employing two data analysis approaches - by treatment randomisation and by stratification using measured n-3 PUFA. Patients (n=20) received 3g/day of fish or placebo oil (FO vs PO) in a double blind randomised protocol prior to elective coronary artery graft and valve surgery. Groups were matched for age, gender, and mean treatment duration (∼20 days). Resected atrial myocardium was s led for assay of viability metabolic markers, and blood obtained for erythrocyte membrane lipid measurement. There was substantial overlap of cell membrane n-3 PUFA content across PO and FO groups, and no group treatment effects on AF incidence or myocardial molecular marker levels were detected. In contrast, data stratification using membrane n-3 PUFA content (at 8% total membrane lipid) achieved significant separation of patients (by n-6:n-3 PUFA ratio), a significant differential cardiac expression of the marker peroxisomal proliferator-activated receptor, but no difference in AF incidence. This small n-3 PUFA case study demonstrates that the same cohort may yield differing findings when evaluated using randomisation or stratification approaches based on direct molecular measures in cell membranes.
The cholinergic blockade of both thermally and non-thermally induced human eccrine sweating
Publisher: Wiley
Date: 18-05-2012
DOI: 10.1113/EXPPHYSIOL.2012.065037
Abstract: Thermally induced eccrine sweating is cholinergically mediated, but other neurotransmitters have been postulated for psychological (emotional) sweating. However, we hypothesized that such sweating is not noradrenergically driven in passively heated, resting humans. To test this, nine supine subjects were exposed to non-thermal stimuli (palmar pain, mental arithmetic and static exercise) known to evoke sweating. Trials consisted of the following four sequential phases: thermoneutral rest passive heating to elevate (by ~1.0°C) and cl mean body temperature and steady-state sweating (perfusion garment and footbath) an atropine sulphate infusion (0.04 mg kg(-1)) with thermal cl ing sustained and following cl removal. Sudomotor responses from glabrous (hairless) and non-glabrous skin surfaces were measured simultaneously (precursor and discharged sweating). When thermoneutral, these non-thermal stimuli elicited significant sweating only from the palm (P < 0.05). Passive heating induced steady-state sweating ranging from 0.20 ± 0.04 (volar hand) to 1.40 ± 0.14 mg cm(-2) min(-1) (forehead), with each non-thermal stimulus provoking greater secretion (P 0.05). However, when the thermal cl was removed, core and skin temperatures became further elevated and sweating was restored (P < 0.05), indicating that the blockade had been overcome, presumably through elevated receptor competition. These observations establish the dependence of both thermal and non-thermal eccrine sweating from glabrous and non-glabrous surfaces on acetylcholine release, and challenge theories concerning the psychological modulation of sweating. Furthermore, no evidence existed for the significant participation of non-cholinergic neurotransmitters during any of these stimulations.
The influence of a basic military training diet on whole blood fatty acid profile and the Omega-3 Index of Australian Army recruits
Publisher: Canadian Science Publishing
Date: 02-2022
Abstract: This study described the whole blood fatty acid profile and Omega-3 Index (O3I) of Australian Army recruits at the commencement and completion of basic military training (BMT). Eighty males (17–34 y, 77.4 ± 13.0 kg, 43.5 ± 4.3 mL/kg/min) and 37 females (17–45 y, 64.3 ± 8.8 kg, 39.3 ± 2.7 mL/kg/min) volunteered to participate (N = 117). Whole blood s les of each recruit were collected using a finger prick in weeks 1 and 11 (n = 82) and analysed via gas chromatography for the relative proportions of each fatty acid (mean [95% confidence interval]). The macronutrient characteristics of the diet offerings was also determined. At commencement there was a low omega-3 status (sum of omega-3 4.95% [4.82–5.07]) and O3I (5.03% [4.90–5.16]) and no recruit recorded an O3I % (desirable). The omega-6/omega-3 (7.04 [6.85–7.23]) and arachidonic acid/eicosapentaenoic acid (AA/EPA) (18.70 [17.86–19.53]) ratios for the cohort were also undesirable. The BMT mess menu provided a maximum of 190 mg/day of EPA and 260 mg/day of docosahexaenoic acid (DHA). The O3I of the recruits was lower by week 11 (4.62% [4.51–4.78], p 0.05), the omega-6/omega-3 increased (7.27 [7.07–7.47], p 0.05) and the AA/EPA remained elevated (17.85 [16.89–18.81]). In conclusion, Australian Army recruits’ omega-3 status remained undesirable during BMT and deserves nutritional attention. Novelty: Australian Army recruits’ Omega-3 Index, at the commencement of BMT, was reflective of the Western-style diet. The BMT diet offered minimum opportunity for daily EPA and DHA consumption. Every recruit experienced a further reduction of their Omega-3 Index during BMT.
Eccentric cycling ergometer to address skeletal muscle dysfunction in hospitalised patients: ergometer design, construction and demonstration
Publisher: BMJ
Date: 08-10-2020
DOI: 10.1136/BMJINNOV-2019-000403
Abstract: Continuous eccentric cycling has demonstrated metabolic efficiency when compared with equivalent concentric workloads. The profile of continuous eccentric cycling is well suited to hospitalised patients, however, its application has been restricted to outpatient settings as ergometers appropriate for the acute setting are currently unavailable. The aim of this study was to construct an eccentric cycle ergometer specifically for use in an acute care hospital ward and demonstrate its performance in healthy subjects. An eccentric cycle ergometer (asynchronous 125 W motor) was constructed with strain gauge technology (SRM PowerMetre) to allow instantaneous biofeedback to the user. Ten healthy participants (20–64 years) were used to test the capacity of the ergometer to maintain consistent force production (repeated 5 min duration) with appropriate physiology responses (heart rate, minute ventilation, arterial saturation, electromyography and muscle tissue oxygen saturation) for low to moderate eccentric workloads. Eccentric power output was consistently achieved without mechanical or ergonomic issues for two workloads (31.1±5.7 W and 56.6±8.8 W, respectively). Participant heart rate (rest: 68±13 bpm) and minute ventilation (rest: 12.4±3.5 L/min) increased incrementally with workload 1 (HR: 83±16 bpm V E : 21.76±6.5 L.min-1, p .001 vs rest) and workload 2 (HR: 94±14 bpm V E : 26.5±8.9 L/min, p .001 vs rest) while local muscle oxygen saturation remained unchanged for both workloads. This study describes the successful construction of an eccentric cycle ergometer and demonstrated the efficacy of the ergometer to deliver constant eccentric workloads in healthy adults. Eccentric cycling could be potentially provided to hospitalised patients using this ergometer.
Dietary lipid modulation of myocardial (β-adrenergic mechanisms, Ca2+-dependent automaticity, and arrhythmogenesis in the marmoset
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-1987
Muscle fatigue resistance in the rat hindlimbin vivofrom low dietary intakes of tuna fish oil that selectively increase phospholipidn-3 docosahexaenoic acid according to muscle fibre typ
Publisher: Cambridge University Press (CUP)
Date: 12-08-2015
DOI: 10.1017/S0007114515002512
Abstract: Dietary fish oil (FO) modulates muscle O 2 consumption and contractile function, predictive of effects on muscle fatigue. High doses unattainable through human diet and muscle stimulation parameters used engender uncertainty in their physiological relevance. We tested the hypothesis that nutritionally relevant FO doses can modulate membrane fatty acid composition and muscle fatigue. Male Sprague–Dawley rats were randomised to control (10 % olive oil (OO) by weight) or low or moderate FO diet (LowFO and ModFO) (HiDHA tuna fish oil) for 15 weeks (LowFO: 0·3 % FO, 9·7 % OO, 0·25 % energy as EPA+DHA ModFO: 1·25 % FO, 8·75 % OO, 1·0 % energy as EPA+DHA). Hindlimb muscle function was assessed under anaesthesia in vivo using repetitive 5 s burst sciatic nerve stimulation (0·05 ms, 7–12 V, 5 Hz, 10 s duty cycle, 300 s). There were no dietary differences in maximum developed muscle force. Repetitive peak developed force fell to 50 % within 62 ( sem 10) s in controls and took longer to decline in FO-fed rats (LowFO 110 ( sem 15) s ModFO 117 ( sem 14) s) ( P ·05). Force within bursts was better sustained with FO and maximum rates of force development and relaxation declined more slowly. The FO-fed rats incorporated higher muscle phospholipid DHA-relative percentages than controls ( P ·001). Incorporation of DHA was greater in the fast-twitch gastrocnemius (Control 9·3 ( sem 0·8) %, LowFO 19·9 ( sem 0·4), ModFO 24·3 ( sem 1·0)) than in the slow-twitch soleus muscle (Control 5·1 ( sem 0·2), LowFO 14·3 ( sem 0·7), ModFO 18·0 ( sem 1·4)) ( P ·001), which was comparable with the myocardium, in line with muscle fibre characteristics. The LowFO and ModFO diets, emulating human dietary and therapeutic supplement intake, respectively, both elicited muscle membrane DHA enrichment and fatigue resistance, providing a foundation for translating these physiological effects to humans.
Up-Regulation of Mitochondrial Antioxidant Superoxide Dismutase Underpins Persistent Cardiac Nutritional-Preconditioning by Long Chain n-3 Polyunsaturated Fatty Acids in the Rat
Publisher: MDPI AG
Date: 04-03-2016
DOI: 10.3390/JCM5030032
Dietary lipid modulation of ventricular fibrillation threshold in the marmoset monkey
Publisher: Elsevier BV
Date: 06-1992
DOI: 10.1016/0002-8703(92)90809-A
Abstract: Programmed electrical stimulation was used to examine the ability of long-term dietary lipid modulation to influence myocardial vulnerability to the induction of ventricular fibrillation in adult marmoset monkeys (Callithrix jacchus). Marmosets fed diets supplemented (to a total of 28.5% of the energy as fat) with polyunsaturated fatty acid (PUFA)-rich tuna fish oil or sunflower seed oil had significantly elevated mean ventricular fibrillation threshold compared with those fed a saturated animal fat supplemented diet or a reference diet not supplemented with fat (11.2% of the energy as fat). Fibrillation threshold was reduced during acute myocardial ischemia induced by coronary artery occlusion but still remained higher in the PUFA-fed animals than either the control or the ischemic threshold in reference or saturated fat supplemented animals. Dietary tuna fish oil was associated with a low incidence of sustained fibrillation episodes and no fatalities. These results indicate that myocardial substrate vulnerability to arrhythmic stimuli is increased during ischemia in a nonhuman primate model but dietary PUFA can reduce vulnerability under both normal and ischemic conditions. Reduced dietary fat intake alone was without effect.
Fish Oil Reduces Heart Rate and Oxygen Consumption During Exercise
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2008
Prescribing More Stringent Design of Randomized Clinical Trials of Omega-3 Polyunsaturated Fatty Acids
Publisher: Elsevier BV
Date: 06-2017
Studies on the cardiovascular depressor actions of St 91 - an analogue of clonidine
Publisher: Elsevier BV
Date: 12-1978
Weighing Up Fish and Omega-3 PUFA Advice with Accurate, Balanced Scales: Stringent Controls and Measures Required for Clinical Trials
Publisher: Elsevier BV
Date: 08-2015
THE INFLUENCE OF AGE AND DIETARY FAT IN AN ANIMAL MODEL OF SUDDEN CARDIAC DEATH
Publisher: Wiley
Date: 02-1989
Absence of coronary or aortic atherosclerosis in rats having dietary lipid modified vulnerability to cardiac arrhythmias
Publisher: Elsevier BV
Date: 05-1990
Dietary fish oil dose- and time-response effects on cardiac phospholipid fatty acid composition
Publisher: Wiley
Date: 10-2004
DOI: 10.1007/S11745-004-1317-0
Abstract: Fish consumption is associated with reduced cardiovascular mortality, and elevated myocardial long-chain n-3 polyunsaturated FA (PUFA) content is implicated in this cardioprotection. This study examined the dose and time responses for incorporation of n-3 PUFA into cellular membranes in rats fed fish oil (FO)-containing diets. For the time course study, rats were fed a 10% FO diet for periods ranging from 0 to 42 d, after which myocardial and erythrocyte membrane fatty acid composition was determined. For the dose response study, rats (n = 3) were fed 0, 1.25, 2.5, 5, or 10% FO for 4 wk, with myocardial, erythrocyte, and skeletal muscle membrane FA determined. Myocardial DHA (22:6n-3) levels doubled in 2 d, stabilizing at levels approximately 200% higher than control after 28 d feeding with 10% FO. By comparison, DHA levels doubled after 4 wk of 1.25% FO feeding. In myocardium and skeletal muscle, EPA (20:5n-3) levels remained low, but in erythrocytes EPA levels reached 50% of DHA levels. The n-3 PUFA were incorporated at the expense of n-6 PUFA in myocardium and skeletal muscle, whereas erythrocytes maintained arachidonic acid levels, and total n-3 PUFA incorporation was lower. This study shows that low doses of FO produce marked changes in myocardial DHA levels maximal incorporation takes up to 28 d to occur and while erythrocytes are a good indicator of tissue n-3 incorporation in stable diets, they vary greatly in their time course and pattern of incorporation.
Building research capacity through community-based projects
Publisher: Wiley
Date: 05-2010
Emergency department care-related causal factors of in-patient deterioration
Publisher: CSIRO Publishing
Date: 24-12-2021
DOI: 10.1071/AH21190
Abstract: Objective The aim of this study was to determine factors related to emergency department (ED) care causing in-patient deterioration. Methods This retrospective cohort study examined in-patient records using the human factors classification framework for patient safety in a regional health service in New South Wales, Australia, between March 2016 and February 2017. Deterioration was defined as either the initiation of a medical emergency team call, cardiac arrest or unplanned admission to the intensive care unit. Results Of the 1074 patients who deteriorated within 72 hours of admission via the ED, the care received in the ED was a contributing factor for 101 patients (9%). The most common human causal factors were poor communication between staff, medical management errors, delayed treatment, medical documentation errors, nursing management errors and unclear policies or guidelines. Communication issues occurred the most when patients had more comorbidities (P = 0.039) and were more likely to occur in the presence of a medical documentation error (odds ratio 4.4 95% confidence interval 1.7–11.3). Unclear policies or guidelines as a factor was most frequent with a surgical diagnosis (34.5% vs 15.7% for surgical vs medical, respectively P = 0.038) and in patients ≥80 years of age (30.0% vs 21.8% for age ≥80 vs years, respectively P = 0.027). Conclusion Quality monitoring and interventions that consider human factors are required to address preventable in-patient deterioration. What is known about the topic? The ED represents the hospital’s point of contact for potentially life-threatening conditions. Adverse event rates for emergency admissions are more than double those of non-emergency admissions. Patients are at particular risk of deterioration on discharge from the ED to the ward in the first 72 hours. Predicting which patients will deteriorate following transfer to the ward remains challenging, with care in the ED hypothesised to play a role. What does this paper add? This paper reveals that in-patient deterioration relating to ED care could be reduced through the routine identification of causal factors within a human factors framework in any patient deterioration event and subsequent evidence-informed interventions to address these factors. It is also extrapolated that the implementation of any intervention should be informed by behaviour-change principles. What are the implications for practitioners? It is implied that there is a need for the clarification and revision of policies and guidelines pertaining to the management of elderly patients, education regarding the critical importance of the often clinically masked vital sign deviations in younger patients and improved communication between staff, especially regarding patients with more comorbidities. Reviews of adverse events, such as patient deterioration, should incorporate a human factors analysis. Regular collation of data following adverse events should occur, with interventions considering all aspects of the factors that led to the event.
Telemedicine in remote Australia: The Royal Flying Doctor Service (RFDS) Medical Chest Program as a marker of remote health
Publisher: Rural and Remote Health
Date: 06-10-2018
DOI: 10.22605/RRH4502
Academic Guidance in Medical Student Research: How Well Do Supervisors and Students Understand the Ethics of Human Research?
Publisher: Springer Science and Business Media LLC
Date: 19-11-2015
Effects of variable linoleate intake on aortic pgl2-like activity and fatty acid composition: difference between rat and marmoset (Callithrix Jacchus)
Publisher: Elsevier BV
Date: 12-1986
DHA-Rich Fish Oil Increases the Omega-3 Index in Healthy Adults and Slows Resting Heart Rate without Altering Cardiac Autonomic Reflex Modulation
Publisher: Informa UK Limited
Date: 11-08-2021
DOI: 10.1080/07315724.2021.1953417
Abstract: Regular fish consumption, a rich source of long-chain omega-3 (ω-3) docosahexaenoic acid (DHA), modifies cardiac electrophysiology. However, human studies investigating fish oil and cardiac electrophysiology have predominantly supplemented therapeutic (high) doses of fish oil (often ω-3 eicosapentaenoic acid (EPA) rich sources). This study examined whether non-therapeutic doses of DHA-rich fish oil modulate cardiac electrophysiology at rest and during cardiovascular reflex challenges to the same extent, if at all, in young healthy adults. Participants (N = 20) were supplemented (double-blinded) with (2x1g.day The baseline O3I (Control: 5.1 ± 1.0 FO: 5.4 ± 0.9 In young healthy adults, dietary achievable doses of ω-3 DHA-rich fish oil exerted a direct slowing effect on resting HR, without compromising the HR response to either dominant sympathetic or parasympathetic modulation.
An open-loop model for investigating mammalian thermosensitivity
Publisher: Elsevier BV
Date: 10-2004
Dietary fish oil reduces skeletal muscle oxygen consumption, provides fatigue resistance and improves contractile recovery in the rat in vivo hindlimb
Publisher: Cambridge University Press (CUP)
Date: 09-08-2010
DOI: 10.1017/S0007114510002928
Abstract: Dietary fish oil modulates skeletal muscle membrane fatty acid composition. Similar changes in heart membrane composition modulate myocardial oxygen consumption and enhance mechanical performance. The rat in vivo autologous perfused hindlimb was used to investigate the influence of membrane composition on skeletal muscle function. Male Wistar rats were fed either saturated fat (SF), n -6 PUFA (linoleic acid rich) or n -3 PUFA (fish oil) diets for 8 weeks. Hindlimb skeletal muscle perfused using the animal's own blood was stimulated via the sciatic nerve (1 Hz, 6-12 V, 0·05 ms) to contract in repeated 10 min bouts. The n -3 PUFA diet markedly increased 22 : 6 n -3 DHA, total n -3 PUFA and decreased the n -6: n -3 PUFA ratio ( P 0·05) in red and white skeletal muscle membranes. There was no difference in initial twitch tension but the n -3 PUFA group maintained greater twitch tension within all contraction bouts and recovered better during rest to produce greater twitch tension throughout the final contraction bout ( P 0·05). Hindlimb oxygen consumption during contraction was significantly lower in the n -3 PUFA group compared with the SF group, producing a significantly higher O 2 efficiency index compared with both SF and n -6 PUFA groups ( P 0·05). Resting oxygen consumption was increased in recovery in the SF group ( P 0·05) but did not change in the n -3 PUFA group. Membrane incorporation of n -3 PUFA DHA following fish oil feeding was associated with increased efficiency of muscle O 2 consumption and promoted resistance to muscle fatigue.
Substitution of Fish for Red Meat or Poultry and Risk of Ischemic Stroke
Publisher: MDPI AG
Date: 03-11-2018
DOI: 10.3390/NU10111648
Abstract: We investigated the risk of ischemic stroke and its subtypes when red meat or poultry was substituted with fish. A total of 57,053 participants aged 50–65 years at baseline were included in the Danish Diet, Cancer and Health study. All participants filled in a food-frequency questionnaire at recruitment. Potential ischemic stroke cases were identified by linkage to the Danish National Patient Register, and all cases were validated and subclassified. Substitutions were investigated as 150 g/week of fish for 150 g/week of red meat or of poultry using multivariable Cox proportional hazard regression models. During 13.5 years of follow-up, 1879 participants developed an ischemic stroke. Replacing red meat or poultry with fish was not associated with the rate of total ischemic stroke, but there was a statistically significant lower rate of large artery atherosclerosis when fish replaced processed (hazard ratio (HR): 0.78 95% confidence interval (CI): 0.67 0.90) and unprocessed (HR: 0.87 95% CI: 0.75 0.99) red meat. A statistically significant higher rate of cardioembolism was found when poultry was replaced by total fish (HR: 1.42 95% CI: 1.04 1.93). When fatty fish replaced unprocessed red meat, a statistically significant lower rate of small-vessel occlusion was found (HR: 0.88 95% CI: 0.77 0.99). In conclusion, replacing red meat with fish was not associated with risk of total ischemic stroke but was associated with a lower risk of subtypes of ischemic stroke.
Cardiac Arrhythmia Prevention in Ischemia and Reperfusion by Low-Dose Dietary Fish Oil Supplementation in Rats
Publisher: Elsevier BV
Date: 12-2020
DOI: 10.1093/JN/NXAA256
Cardiac physiology and clinical efficacy of dietary fish oil clarified through cellular mechanisms of omega-3 polyunsaturated fatty acids
Publisher: Springer Science and Business Media LLC
Date: 04-04-2014
DOI: 10.1007/S00421-014-2876-Z
Abstract: Reduced cardiac mortality and morbidity have long been observed in association with omega-3 long chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish consumption, without clear physiological explanation. This review seeks to identify mechanisms of action based on evidence: of physiological effects, active components and effective intakes. Fish oil pleiotropic effects reveal actions that are either intrinsic: effects on cardiac function dependent upon membrane incorporation or extrinsic: indirect cardiac effects through vascular disease. Extrinsic actions require EPA + DHA doses >3 g/day. Intrinsic effects derive from usual dietary intakes, <1 g/day and include improved myocardial oxygen efficiency, heart rate, nutritional preconditioning against ischaemic injury, arrhythmias and heart failure. Myocardial Na(+) and K(+) currents are non-selectively modulated by omega-3 and omega-6 PUFA to stabilise cells in vitro, but not by fish oil-induced membrane change. In contrast, cellular Ca(2+) overload involved in ischaemic injury, arrhythmia and spontaneous pacemaker activity are modulated by both dietary fish oil and in vitro omega-3 LC-PUFA. A potential linking role of bioactive epoxy and hydroxy PUFA derivatives requires investigation. Omega-3 DHA predominates over EPA in population intake, is preferentially incorporated into myocardium and is selectively active in heart rate and arrhythmia modulation, but EPA predominates in clinical trials. Myocardial selectivity for DHA and independent intrinsic and extrinsic physiological mechanisms underpinning erse clinical endpoints can explain some contradictory outcomes of clinical trials. Intrinsic modulation of intracellular Ca(2+) handling provides a unifying physiologically plausible basis for intrinsic fish oil actions and insight to nutritional optimisation of cardiac function.
Membrane Basis for Fish Oil Effects on the Heart: Linking Natural Hibernators to Prevention of Human Sudden Cardiac Death
Publisher: Springer Science and Business Media LLC
Date: 07-2005
DOI: 10.1007/S00232-005-0787-Y
Abstract: The concept that diet-induced changes in membrane lipids could modify heart function partly arose from observations that membrane composition and physical properties were closely associated with the capacity of the heart to respond appropriately to torpor and hibernation. Observations of natural hibernators further revealed that behavior of key membrane-bound enzymes could be influenced through the lipid composition of the cell membrane, either by changing the surrounding fatty acids through reconstitution into a foreign lipid milieu of different composition, or by alteration through diet. Myocardial responsiveness to beta-adrenoceptor stimulation, including initiation of spontaneous dysrhythmic contractions, was altered by both hibernation and dietary modulation of membrane fatty acids, suggesting modified vulnerability to cardiac arrhythmia. Subsequent studies using whole-animal models recognized that vulnerability to ventricular fibrillation decreased as the polyunsaturated: saturated fat (P:S) ratio of the diet increased. However, dietary fish oils, which typically contain at least 30% saturated fatty acids and only 30% long-chain n-3 (omega-3) polyunsaturated fatty acids (PUFA), exhibit antiarrhythmic effects that exceed the predicted influence of the P:S ratio, suggesting properties unique to the long-chain n-3 PUFA. Large-scale clinical trials and epidemiology have confirmed the arrhythmia prevention observed in vitro in myocytes, papillary muscles, and isolated hearts and in whole-animal models of sudden cardiac death. Some progress has been made towards a biologically plausible mechanism. These developments highlight nature's ability to provide guidance for the most unexpected applications.
Effects of diets high in whey, soy, red meat and milk protein on body weight maintenance in diet-induced obesity in mice
Publisher: Wiley
Date: 06-2008
Dietary modulation of lipid metabolism and mechanical performance of the heart
Publisher: Springer Science and Business Media LLC
Date: 10-1992
DOI: 10.1007/BF01270564
Abstract: Partners Health Online is a portal to a broad set of consumer health information. As such, the site allows public access to health and disease information as well as Partners-specific information resources (e.g., departments, physicians, clinical trials, classes, support groups). Partners Health Online licenses its health care articles from Healthwise, Inc. This poster describes patterns of activity at Health Online over a 3-year period. The data were analyzed in terms of traffic patterns, visitor characteristics, and information-seeking behavior.
Autologous Pump-Perfused Rat Hind Limb Preparation for Investigating Muscle Function and MetabolismIn Vivo
Publisher: Wiley
Date: 08-2013
DOI: 10.1111/MICC.12048
Abstract: Oxygen delivery, underpinned by vascular tone, is the principle limiting factor in the study of skeletal muscle physiology, particularly during muscle contraction. The aim of this study was to develop an autologous perfused rat hind limb preparation for the study of skeletal muscle contractile function. Adult Wistar rats were surgically prepared using a by-pass system for pump-controlled arterial blood flow to, and venous return from the hind limb during periods of quiescence and twitch contraction of the gastrocnemius-plantaris-soleus muscle bundle. During rest, hind limb perfusion pressure (102 ± 5 mmHg) was not different to systemic arterial pressure (99 ± 4 mmHg). Hind limb pressure was responsive to vasoconstrictors and vasodilators (±50 mmHg). The arterial PO2 (100 ± 3 mmHg), O2 saturation, and acid-base balance (pH: 7.42 ± 0.01) contributed to resting hind limb (a-v)O2 difference (4.8 ± 0.5 mL/100 mL) and VO2 (0.31 ± 0.03 μmol/g/min wet weight). Repetitive isometric twitch tension (1 Hz, 0.05 ms, 10 minutes) was best maintained at a flow rate of 2 mL/min (VO2 increased fivefold during muscle contraction) and efficiency of oxygen use increased from 0.27 ± 0.08-0.52 ± 0.07 N/μmol/min. The autologous rat hind limb provided resting vascular tone allowing maintenance of perfusion pressure at flows within the physiological range. Oxygen delivery supported repetitive twitch contractions and facilitated measurement of active metabolism.
The effect of different dietary lipid supplements on the nonesterified fatty acid composition of normoxic rat hearts: A link between nutrition and cardiac arrhythmia
Publisher: Elsevier BV
Date: 12-1992
THE INFLUENCE OF PROSTAGLANDINS ON NORADRENALINE-INDUCED VASOCONSTRICTION IN ISOLATED PERFUSED MESENTERIC BLOOD VESSELS OF THE RAT
Publisher: Wiley
Date: 1978
DOI: 10.1111/J.1476-5381.1978.TB07005.X
Abstract: 1 The report of the depression by indomethacin of vasoconstrictor responses to noradrenaline and their partial restoration by prostaglandin E(2) (PGE(2)) and PGE(1) in rat isolated perfused mesenteric blood vessels was investigated. The further suggestion that prostaglandins may be necessary for the combination of noradrenaline with the alpha-adrenoceptor in this tissue was also studied.2 The reported depression by indomethacin was confirmed and was further shown to be in the form of a concentration-dependent flattening of the noradrenaline concentration-effect curve.3 A concentration-dependent restorative effect was observed for all prostaglandins studied. The decreasing order of potency for the restoration towards normal of the indomethacin-depressed responses to noradrenaline was: PGE(2), PGE(1), PGA(1), PGF(2alpha), PGA(2).4 The prostaglandins studied were not uniform in their restorative actions and could be separated into two groups. PGE(2) and PGE(1) restored responses towards the control level whereas PGA(1), PGA(2) and PGF(2alpha) increased responses to an above control level and did so over a smaller concentration range. The possibility of several prostaglandin receptors is discussed.5 At concentrations equi-effective in restoring depressed responses to control levels PGA(1) but not PGE(2), caused a parallel shift of the noradrenaline concentration-effect curve to the left and a small, gradual rise in the basal perfusion pressure.6 The reason for the differing effects remains obscure but does not seem to involve a change in the alpha-adrenoceptor as indicated by the pA(2) of phentolamine. Furthermore, the restorative and potentiating effect of PGA(1) is not mediated by blockade of neuronal uptake of noradrenaline.7 It appears that prostaglandins are required for the vasoconstrictor action of noradrenaline in rat mesenteric blood vessels and that this effect is distal to the drug-receptor interaction. The possible involvement of prostaglandins with intracellular calcium ions is discussed.
Marine n-3 Polyunsaturated Fatty Acids and the Risk of Ischemic Stroke
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2019
DOI: 10.1161/STROKEAHA.118.023384
Abstract: We hypothesized that total marine n-3 polyunsaturated fatty acids (PUFA), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the diet and in adipose tissue (biomarkers of long-term intake and endogenous exposure) were inversely associated with the risk of ischemic stroke and its subtypes. The Diet, Cancer and Health cohort consisted of 57 053 participants aged 50 to 65 years at enrolment. All participants filled in a food frequency questionnaire and had an adipose tissue biopsy taken at baseline. Information on ischemic stroke during follow-up was obtained from The Danish National Patient Register, and all cases were validated. Cases and a random s le of 3203 subjects from the whole cohort had their fatty acid composition of adipose tissue determined by gas chromatography. During 13.5 years of follow-up 1879 participants developed an ischemic stroke. Adipose tissue content of EPA was inversely associated with total ischemic stroke (hazard ratio [HR], 0.74 95% CI, 0.62–0.88) when comparing the highest with the lowest quartile. Also, lower rates of large artery atherosclerosis were seen with higher intakes of total marine n-3 PUFA (HR, 0.69 95% CI, 0.50–0.95), EPA (HR, 0.66 95% CI, 0.48–0.91) and DHA (HR, 0.72 95% CI, 0.53–0.99), and higher adipose tissue content of EPA (HR, 0.52 95% CI, 0.36–0.76). Higher rates of cardioembolism were seen with higher intakes of total marine n-3 PUFA (HR, 2.50 95% CI, 1.38–4.53) and DHA (HR, 2.12 95% CI, 1.21–3.69) as well as with higher adipose tissue content of total marine n-3 PUFA (HR, 2.63 95% CI, 1.33–5.19) and DHA (HR, 2.00 95% CI, 1.04–3.84). The EPA content in adipose tissue was inversely associated with small-vessel occlusion (HR, 0.69 95% CI, 0.55–0.88). EPA was associated with lower risks of most types of ischemic stroke, apart from cardioembolism, while inconsistent findings were observed for total marine n-3 PUFA and DHA.
Low dietary fish-oil threshold for myocardial membrane n-3 PUFA enrichment independent of n-6 PUFA intake in rats
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1194/JLR.M004069
Differences in fatty acid composition of various tissues of the marmoset monkey (Lithrix jacchus after different lipid supplemented diets
Publisher: Elsevier BV
Date: 1992
DOI: 10.1016/0300-9629(92)90551-Z
Abstract: 1. The fatty acid composition of different muscles, organs and blood components of the marmoset monkey were examined after long-term feeding of several well defined lipid supplemented diets. 2. Similarities between the fatty acid composition of cardiac and skeletal muscles which persisted after all diets suggest that biopsy of skeletal muscle may have an important diagnostic value in this and other primate species. 3. The relationship between the dietary intake of in idual fatty acids and their proportions in different tissues is both complex and variable. 4. However, the lipid metabolism of Callithrix jacchus recommends this small non-human primate as a most suitable species for the study of lipid nutrition.
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