Medium-chain Fatty Acid Diet Research Articles

Different Fatty Acid Supplementation in Low-Protein Diets Regulate Nutrient Utilization and Lipid and Amino Acid Metabolism in Weaned Pigs Model.

This study was conducted to evaluate the effects of a low-protein (LP) diet supplemented with sodium butyrate (SB), medium-chain fatty acids (MCFAs) and n-3 polyunsaturated fatty acids (PUFAs) on nutrient utilization and lipid and amino acid metabolism in weaned pigs. A total of 120 Duroc × Landrace × Yorkshire pigs (initial body weight: 7.93 ± 0.65 kg) were randomly assigned to five dietary treatments, including the control diet (CON), LP diet, LP + 0.2% SB diet (LP + SB), LP + 0.2% MCFA diet (LP + MCFA) and LP + 0.2% n-3 PUFA diet (LP + PUFA). The results show that the LP + MCFA diet increased (p < 0.05) the digestibility of dry matter and total P in pigs compared with the CON and LP diets. In the liver of the pigs, the metabolites involved in sugar metabolism and oxidative phosphorylation significantly changed with the LP diet compared with the CON diet. Compared with the LP diet, the altered metabolites in the liver of the pigs fed with the LP + SB diet were mainly associated with sugar metabolism and pyrimidine metabolism; the altered metabolites in the liver of pigs fed with the LP + MCFA and LP + PUFA diets were mainly associated with lipid metabolism and amino acid metabolism. In addition, the LP + PUFA diet increased (p < 0.05) the concentration of glutamate dehydrogenase in the liver of pigs compared with the LP diet. Furthermore, the LP + MCFA and LP + PUFA diets increased (p < 0.05) the mRNA abundance of sterol regulatory element-binding protein 1 and acetyl-CoA carboxylase in the liver compared with the CON diet. The LP + PUFA diet increased (p < 0.05) mRNA abundances of fatty acid synthase in the liver compared with the CON and LP diets. Collectively, the LP diet supplemented with MCFAs improved nutrient digestibility, and the LP diet supplemented with MCFAs and n-3 PUFAs promoted lipid and amino acid metabolisms.

Familial chylomicronemia syndrome: a case report

BackgroundFamilial chylomicronemia is an extremely rare disease. Lipoprotein lipase deficiency, lipoprotein defect or lipoprotein receptor defect are the main genetic causes of familial chylomicronemia.Case presentationWe report a rare case of hypertriglyceridemia which was diagnosed at 24 days after birth. A newborn south east Asian baby born for G3P2A1 mother was presented with hematuria at 24 days at the hospital. The patient's family history is significant for pink blood in an elder sibling who died within a few months of birth without a proper diagnosis. Physical examination was not significant for any findings. Urinalysis revealed numerous RBC in the urine. Blood draw to perform renal function test revealed a characteristic pink blood. Baby’s blood was normal and red in color at the time of birth. During the present visit, although most of the blood test were not able to be carried out by the regular laboratory instruments, the patient’s lipid profile was alarmingly high with triglyceride levels over 4000 mg/dL. Due to a very high triglyceride level in a neonate and a significant familial history, a genetic cause of hypertriglyceridemia is suspected. Upon diagnosis, baby was discontinued of breast feeding completely and was given a special diet devoid of triglyceride and containing medium chain fatty acid diet and was also started with fenofibrate. After a month and a half, follow up tests were conducted which showed the triglyceride level was reduced to 1300 and a reversal of the blood color from pink to red. Since the imported diet was extremely expensive for the family, the patient was put on skimmed milk with medium-chain triglyceride (MCT) oil. With 6 weeks of treatment, baby’s condition has improved and is thriving well.ConclusionsOur case reports an extremely rare and fatal condition and illustrated the significance of timely diagnosis and intervention for saving the life of the baby.

Efficacy of natural alternatives to antibiotic on the growth performance, gut microbial population, intestinal morphology, and serum biochemical metabolites of broiler chickens

The present study investigated the effects of different feed additives on growth performance, carcass characteristics, gut microbial population, intestinal morphology, and blood metabolites of broiler chickens. A total of 540, day-old Ross 308 male chicks were randomly distributed into 6 dietary treatments with 6 replicate pens per treatment for 35 days. The birds fed on a basal diet without feed additive (CON) or the basal diet supplemented with 0.25 g/kg antibiotic as growth promoter (AGP), 1 g/kg essential oils (EO), 1.7 g/kg synbiotic (SYN), 3 g/kg medium-chain fatty acids (MCFA), and 1 mL/L essential oils in drinking water (EOW). The additives improved the body weight gain (p = .004) and feed conversion ratio (p = .02) compared to the CON group during the whole trial. The serum concentration of cholesterol was lower in the birds fed the MCFA diet and serum concentration of low-density lipoprotein cholesterol (LDL) decreased in MCFA and SYN groups. The relative weight of spleen was the greatest in MCFA group (p = .01). Feeding birds diets containing different additives decreased the population of coliform (p = .002) and Clostridium perfringens (p = .01) while Lactobacillus population was greater in broilers offered EOW, SYN, and MCFA supplements (p = .02). The jejunal villus height enhanced in the broiler chickens which received AGP and MCFA additives (p = .008). It is concluded that EOW, SYN, MCFA, and EO as alternatives for AGP improved the growth performance and intestinal morphometric indices and reduced the caecal pathogenic bacteria in broiler chickens. Highlights Adding MCFA to diet and EO to the drinking water improved BWG and FCR in broiler chickens. Dietary supplementation of MCFA decreased serum total cholesterol, increased caecal LAB population, and improved intestinal villus height. All supplements as AGP alternatives had beneficial effects on suppressing the pathogenic bacteria.

Feeding Conjugated Linoleic Acid without a Combination of Medium-Chain Fatty Acids during Late Gestation and Lactation Improves Pre-Weaning Survival Rates of Gilt and Sow Progeny.

Simple SummaryA number of feeding strategies have been used in attempts to improve performance of progeny born to primiparous sows, which are born lighter, grow slower, and have higher rates of mortality than progeny born to older sows. The current study examined whether feeding conjugated linoleic acid (CLA) or a commercial medium-chain fatty acid (MCFA) product alone or in combination to primiparous and multiparous sows improved pre-weaning growth and survival of their progeny. Feeding CLA or MCFA failed to improve reproductive performance of primiparous or multiparous sows or the performance of their progeny during lactation, and there was no added benefit of feeding these products for gilt progeny. However, feeding CLA alone improved the survival of gilt and sow progeny. Further examination of the different inclusion levels and the timing of CLA feeding may be required in order for the use of this additive to be more efficacious.Feeding conjugated linoleic acid (CLA) or medium-chain fatty acids (MCFA) to dams has been shown to improve progeny growth and survival, and hence may be particularly advantageous to gilt progeny. Primiparous (n = 129) and multiparous sows (n = 123; parities 3 and 4) were fed one of four diets from day 107 of gestation (107.3 ± 0.1 days) until weaning (day 27.2 ± 0.1 of lactation): (i) control diet; (ii) 0.5% CLA diet; (iii) 0.1% MCFA diet; and (iv) equal parts of (ii) and (iii). Progeny performance data were collected and, from a subset of sows (n = 78) and their piglets (n = 144), a colostrum (day 0), milk (day 21), and piglet serum sample (day 3) were analyzed for immunoglobulin G and several selected metabolites. Liveborn pre-weaning mortality tended to be lowest (p = 0.051) in piglets from sows fed 0.5% CLA. However, sows fed the CLA diet had more (p = 0.005) stillbirths than those on the other diets. There were few effects of diet or the dam parity x diet interaction (p ≥ 0.05) on other parameters. Overall, feeding CLA or MCFA did not improve the performance of primiparous sows, multiparous sows, or their progeny.

Effect of dietary supplementation with medium chain fatty acids on growth performance, intestinal histomorphology, lipid profile and intestinal microflora of broiler chickens

The aim of the present study was to assess the effects of medium-chain fatty acid (MCFA) diet supplementation on growth performance, intestinal histomorphology, serum biochemistry and intestinal microflora of broiler chickens. The study was performed on 180 one-day-old broilers of the same origin (Cobb 500 hybrid), over a 42-day period. They were fed diets supplemented with three treatments: control group (basal diet without supplementation); group with MCFA supplementation; and group with MCFA and coccidiostat supplementation. Broiler chickens fed diets supplemented with MCFAs had a significantly greater final bodyweight. The weights of carcass cuts (breast, drumsticks with thighs and wings) were greater in broilers receiving MCFAs than in control broilers. The addition of MCFAs to broiler diet significantly increased villus length and crypt depth in the duodenum and caecum, and significantly decreased villus width in the duodenum and ileum. Additionally, serum HDL-cholesterol and triglyceride concentrations were increased significantly in broilers with MCFA dietary supplementation. The results indicated that the MCFA diet supplementation had a beneficial effect on the performance of broiler chickens, their intestinal histomorphology and microflora.Keywords: Carcass characteristics, coccidiostat supplementation, nutrition, poultry, serum biochemistry

Chylothorax as a Post-Operative Complication of Orthotopic Heart Transplantation

Objectives Recognize chylothorax as a complication of OHT, and LVAD implantation and explantation. Introduction Chylothorax is a rare complication of thoracic surgery with a reported incidence of 0.24% - 0.5%, however there have been only two previous reports of chylothorax after orthotopic heart transplantation (OHT). We report the first instance of chylothorax complicating OHT at the time of ventricular assist device (VAD) explantation. Case report A 47 y.o. man with ischemic cardiomyopathy who required TandemHeart, and subsequent HeartMate 2 VAD placement with closure of ASD. He underwent a HeartMate 2 exchange four months later, and OHT 14 months later. After OHT, on post-operative day (POD) 8, he had milky fluid from a mediastinal Blakemore tube. Fluid triglyceride level was 1477 mg/dl. The patient was placed on a very low fat diet and the drainage decreased from 235mL/24hrs to 90mL/24hrs. When challenged with a high fat diet, he had a recurrent chylous effusion. On POD 28 he reported Discussion The appearance of this complication after VAD explantation may be of particular importance as continued developments and improvements in VAD technology lead to an increase in patient survival, VAD implantation, and exchange. As this occurs, awareness of this rare complication becomes more important. Chylothorax provides a particular challenge in the management of the transplant patient, as indwelling chest tubes, effects on nutritional status and the immune system are noteworthy. The primary treatment for chylothorax is low fat or medium-chain fatty acid diet. If this fails, nil per os status with total parenteral status is the second line therapy. In a patient post OHT, who is immunosuppressed, maintaining adequate nutrition is of paramount importance. Additionally, loss of chyle has potential implications in the management of post-transplant immunosuppression. Cyclosporine is secreted in chyle. The loss of chyle into the pleural cavity decreases the circulating levels of cyclosporine, which render achieving a therapeutic level difficult. Furthermore, cyclosporine has been demonstrated to increase chyle formation, which makes resolution of chylothorax more difficult in patients who require cyclosporine therapy. Lastly, chyle contains numerous lymphocytes, with a typical cell count revealing >50% lymphocytes. Loss of chyle, then, leads to a rapid and abnormal loss of lymphocytes. This may complicate administration and monitoring of lymphocyte-reducing anti-rejection therapies which are paramount to graft health in the early post-operative period. Conclusion Post-OHT chylothorax is an uncommon, but noteworthy complication. Management is similar to non-transplant patients, requires close follow-up and may adversely affect outcomes, due to effects on nutritional status and immunological risk.

Effect of GPR84 deletion on obesity and diabetes development in mice fed long chain or medium chain fatty acid rich diets.

Although there is good evidence showing that diets rich in medium chain fatty acids (MCFAs) have less marked obesogenic and diabetogenic effects than diets rich in long chain fatty acids (LCFAs), the role of the pro-inflammatory, medium chain fatty acid receptor (GPR84) in the aetiology of obesity and glucose intolerance is not well characterised. We set out to determine whether GPR84 expression influences obesity and glucose intolerance susceptibility in MCFA and LCFA rich diet fed mice. Wild type (WT) and GPR84 knockout (KO) mice were fed a control, MCFA or LCFA diet, and body mass, heart, liver and epididymal fat mass was assessed, as well as glucose tolerance and adipocyte size. LCFA diets increased body mass and decreased glucose tolerance in both WT and GPR84 KO animals while MCFA diets had no effect on these parameters. There were no differences in body weight when comparing WT and GPR84 KO mice on the respective diets. Glucose tolerance was also similar in WT and GPR84 KO mice irrespective of diet. Liver mass was increased following LCFA feeding in WT but not GPR84 KO mice. Hepatic triglyceride content was increased in GPR84 KO animals fed MCFA, and myocardial triglyceride content was increased in GPR84 KO animals fed LCFA. GPR84 deletion had no effects on body weight or glucose tolerance in mice fed either a high MCFA or LCFA diet. GPR84 may influence lipid metabolism, as GPR84 KO mice had smaller livers and increased myocardial triglyceride accumulation when fed LCFA diets, and increased liver triglyceride accumulation in responses to increased dietary MCFAs.

Effects of different fatty acid chain lengths on fatty acid oxidation-related protein expression levels in rat skeletal muscles.

Skeletal muscles can adapt to dietary interventions that affect energy metabolism. Dietary intake of medium-chain fatty acids (MCFAs) enhances mitochondrial oxidation of fatty acids (FAO) in type IIa skeletal muscle fibers. However, the effect of MCFAs diet on mitochondrial or cytoplasmic FAO-related protein expression levels in different types of muscle fibers remains unclear. This study aims to examine the effects of a high-fat diet, containing MCFAs, on mitochondrial enzyme activities and heart-type fatty acid-binding protein (H-FABP) levels in different types of skeletal muscle fibers. Five-week-old male Wistar rats were assigned to one of the following three dietary conditions: standard chow (SC, 12% of calories from fat), high-fat MCFA, or high-fat long-chain fatty acids (LCFAs) diet (60% of calories from fat for both). The animals were provided food and water ad libitum for 4 weeks, following which citrate synthase (CS) activity and H-FABP concentration were analyzed. The epididymal fat pads (EFP) were significantly smaller in the MCFA group than in the LCFA group (p < 0.05). MCFA-fed group displayed an increase in CS activity compared with that observed in SC-fed controls in all types of skeletal muscle fibers (triceps, surface portion of gastrocnemius (gasS), deep portion of gastrocnemius (gasD), and soleus; p < 0.05,). H-FABP concentration was significantly higher in the LCFA group than in both the SC-fed and MCFA-fed groups (triceps, gasS, gasD, and soleus; p < 0.05,). However, no significant difference was observed in the H-FABP concentrations between the SC-fed and MCFA-fed groups. The results of this study showed that the MCFA diet can increase the expression of the mitochondrial enzyme CS, but not that of H-FABP, in both fast- and slow-twitch muscle fibers, suggesting that H-FABP expression is dependent on the chain length of fatty acids in the cytoplasm of skeletal muscles cells.

Fatal pulmonary embolism complicating a postoperative chylothorax despite adequate thromboprophylaxis

Chylothorax is a recognized complication of intrathoracic surgery, but its occurrence after coronary artery bypass grafting (CABG) is very rare. We report a case of a fatal pulmonary embolism as a complication of chylothorax following CABG. The patient was an 82-year-old woman who presented with increasing chest pain 2 weeks after discharge after an uncomplicated CABG. A computerized tomography (CT) scan with contrast angiogram showed a left-sided pleural effusion and no concurrent pulmonary embolus. Analysis of the pleural effusion revealed a chylothorax, which was treated with chest tube drainage and total parenteral nutrition followed by an oral medium-chain fatty acid diet. The patient improved steadily but, on day 6, she developed acute hypoxemic respiratory failure and shock. A CT angiogram revealed a massive pulmonary embolus and, despite thrombolysis, the patient died. Autopsy confirmed an acute saddle embolus in the pulmonary trunk. The patient had received appropriate venous thromboembolism prophylaxis with subcutaneous unfractionated heparin during her hospital course. This is the first reported case of a fatal pulmonary embolism that occurred in the setting of a post-CABG chylothorax in adults. The occurrence of this complication despite unfractionated heparin thromboprophylaxis may suggest a role for other, more effective medications, such as low molecular weight heparin or fondaparinux in patients with chylothorax.

Changes in food intake, metabolic parameters and insulin resistance are induced by an isoenergetic, medium-chain fatty acid diet and are associated with modifications in insulin signalling in isolated rat pancreatic islets

Long-chain fatty acids are capable of inducing alterations in the homoeostasis of glucose-stimulated insulin secretion (GSIS), but the effect of medium-chain fatty acids (MCFA) is poorly elucidated. In the present study, we fed a normoenergetic MCFA diet to male rats from the age of 1 month to the age of 4 months in order to analyse the effect of MCFA on body growth, insulin sensitivity and GSIS. The 45% MCFA substitution of whole fatty acids in the normoenergetic diet impaired whole body growth and resulted in increased body adiposity and hyperinsulinaemia, and reduced insulin-mediated glucose uptake in skeletal muscle. In addition, the isolated pancreatic islets from the MCFA-fed rats showed impaired GSIS and reduced protein kinase Ba (AKT1) protein expression and extracellular signal-related kinase isoforms 1 and 2 (ERK(1/2)) phosphorylation, which were accompanied by increased cellular death. Furthermore, there was a mildly increased cholinergic sensitivity to GSIS. We discuss these findings in further detail, and advocate that they might have a role in the mechanistic pathway leading to the compensatory hyperinsulinaemic status found in this animal model.

High dietary intake of medium-chain fatty acids during pregnancy in rats prevents later-life obesity in their offspring

We investigated the effects of dietary fatty acids of different chain lengths during pregnancy in the rat on the susceptibility of offspring to later-life obesity and the underlying mechanisms. Pregnant rats were fed three different diets: standard (STD), high medium-chain fatty acids (MCFA); and high long-chain fatty acids (LCFA). The male offspring were assigned to three groups: STD control, MCFA and LCFA according to the maternal diets and suckled by dams fed with STD during pregnancy and lactation. After weaning, the offspring were fed with STD from 3 to 8 weeks of age. At the age of 8 weeks, rats in three groups: high-fat diet (HFD) control, MCFA and LCFA were fed with HFD until 14 weeks of age in an attempt to induce obesity, and rats in the HFD control group were selected randomly from the STD control group. Body weight and body fat content were decreased in the MCFA group accompanied by down-regulated mRNA expression of fatty acid synthase and acetyl-coA carboxylase 1, and increased mRNA and protein expression of adenosine monophosphate (AMP)-activated protein kinase (AMPK), carnitine palmitoyltransferase 1 and uncoupling protein 3 compared with the corresponding controls at 3, 8 and 14 weeks of age. The results suggested that the MCFA diet during pregnancy prevented later-life obesity in the offspring when they were exposed to HFD in later life, which might be related to programming of the expression of genes involved in fatty acid metabolism.

Chyluria after Partial Nephrectomy: Case Report and Review of the Literature

We report a case of 61-year-old male who presented with chyluria after partial nephrectomy. During workup for appendicitis, an incidental exophytic renal mass was revealed on CT scan. The patient ultimately underwent uncomplicated open partial nephrectomy. Postoperatively, his JP drain output turned milky white with urine remaining clear. JP fluid analysis was consistent with lymph. At 3 weeks postsurgery, his drain output decreased, but his urine turned milky white. Urinalysis confirmed fat in the urine. CT imaging revealed chyloma/urinoma with extravasation. The patient was initially treated conservatively, with a medium-chain fatty acid diet and then ureteral stenting. His stent was eventually removed and his chlyuria resolved 14 weeks later.In nonendemic countries, nonparasitic chyluria is exceedingly rare and postsurgical chyluria even more so. We review the sequelae of untreated disease and surgical options for intractable chyluria not responsive to conservative management.In non-endemic countries, non-parasitic chyluria is exceedingly rare, and post surgical chyluria even more so. We review the sequelae of untreated disease and surgical options for intractable chyluria not responsive to conservative management.

CARNITINE PALMITOYL TRANSFERASE‐I INHIBITION IS NOT ASSOCIATED WITH CARDIAC HYPERTROPHY IN RATS FED A HIGH‐FAT DIET

1. Cardiac lipotoxicity is characterized by hypertrophy and contractile dysfunction and can be triggered by impaired mitochondrial fatty acid oxidation and lipid accumulation. The present study investigated the effect of dietary fatty acid intake alone and in combination with inhibition of mitochondrial fatty acid uptake with the carnitine palmitoyl transferase (CPT)-I inhibitor oxfenicine. Long-chain fatty acids activate peroxisome proliferator-activated receptors (PPAR), thus mRNA levels of PPAR target genes were measured. 2. Rats were untreated or given the CPT-I inhibitor oxfenicine (150 mg/kg per day) and were fed for 8 weeks with either: (i) standard low-fat chow (10% of energy from fat); (ii) a long-chain saturated fatty acid diet; (iii) a long-chain unsaturated fatty acid diet; or (iv) a medium-chain fatty acid diet (which bypasses CPT-I). High-fat diets contained 60% of energy from fat. 3. Cardiac triglyceride content was increased in the absence of oxfenicine in the saturated fat group compared with other diets. Oxfenicine treatment further increased cardiac triglyceride stores in the saturated fat group and caused a significant increase in the unsaturated fat group. Despite elevations in triglyceride stores, left ventricular mass, end diastolic volume and systolic function were unaffected. 4. The mRNA levels of PPAR-regulated genes were increased by the high saturated and unsaturated fat diets compared with standard chow or the medium chain fatty acid chow. Oxfenicine did not further upregulate PPARalpha target genes within each dietary treatment group. 5. Taken together, the data suggest that consuming a high-fat diet or inhibiting CPT-I do not result in cardiac hypertrophy or cardiac dysfunction in normal rats.

Acute Heart Failure—Basic Pathomechanism and New Drug Targets

In view of the high incidence of heart failure and sudden cardiac death, efforts in the development of compounds which target-specific mechanisms such as a reduced expression of SERCA2, the Ca2+ pump of sarcoplasmic reticulum, of hypertrophied cardiomyocytes of pressure-overloaded or infarcted hearts should be strengthened. Lead compounds for correcting a dysregulated gene expression are the carnitine palmitoyltransferase-1 (CPT-1) inhibitors etomoxir and oxfenicine. Since bypassing the CPT-1 inhibition by a medium-chain fatty acid diet had a lesser effect on myosin V1 proportion than on lipid droplet number, one has to infer also other mechanisms such as PPARalpha activation (FOXIB/PPARalpha). In view of the intricate interrelationship between depressed pump function and malignant arrhythmias, stimulation of endogenous antiarrhythmogenic mechanisms linked to an enhanced production of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) could potentially provide alternatives to the administration of 1 g EPA and DHA ethyl esters (minimum 84% EPA + DHA) for secondary prevention of myocardial infarction. The apparently greater efficacy of omega-3 fatty acids in post-myocardial infarction patients (GISSI-Prevention study) compared with ICD patients (SOFA study) can be attributed to the greater ischemia-induced release of membrane-bound EPA and DHA and a better compliance (one vs. four capsules daily).

Chylous ascites following retroperitoneal lymphadenectomy for testes cancer

A 31-year-old man underwent a radical orchiectomy for a stage I mixed germ-cell tumor with angiolymphatic invasion. A subsequent laparoscopic retroperitoneal lymphadenectomy was complicated by a laceration to the aorta at the ostia of the more inferior of two right renal arteries. This was repaired following conversion to an open laparotomy. The patient presented 14 days later with genital swelling and increasing abdominal girth. Physical examination, abdominal and pelvic CT, laboratory albumin testing, lymphoscintogram and lymphangiogram. Chylous ascites with tracking of lymphatic fluid into the left groin through a defect in the internal inguinal ring. Conservative management with salt restriction, a medium-chain fatty-acid diet and diuretics; exploratory laparoscopy, during which a small left inguinal hernia was repaired and chylous fluid was drained. Following further leakage, the patient was placed on total parenteral nutrition, followed by image-guided sclerotherapy with doxycycline.

Effects of medium chain fatty acids (MCFA), myristic acid, and oleic acid on serum lipoproteins in healthy subjects

In this study we investigated the effects on lipoproteins of medium chain fatty acids (MCFA) and myristic acid relative to those of oleic acid. Thirty-seven women and 23 men consumed a 3-wk run-in diet enriched in oleic acid followed by a 6-wk test diet rich in MCFA (n = 21), myristic (n = 20), or oleic acid (n = 19). Experimental fats were incorporated into solid foods. Total fat intake was 40 En% fat. The dietary compositions were the same except for 10 En%, which was provided by MCFA, myristic, or oleic acids, respectively. With the myristic acid diet, low density lipoprotein (LDL) cholesterol was 0.37 mmol/L higher compared with the oleic acid diet (P = 0.0064 for difference in changes). The MCFA diet increased LDL cholesterol, though not significantly, with 0.23 mmol/L relative to the oleic acid diet (P = 0.0752). Compared with the oleic acid diet, HDL cholesterol concentrations increased with the myristic acid diet by 0.10 mmol/L (P = 0.0273) but not with the MCFA diet. The MCFA diet slightly elevated triacylglycerol concentrations, but responses did not significantly differ between the diets. The MCFA diet significantly decreased the apoA-I to apoB ratio compared with both other diets (P < 0.02). We conclude that MCFA raise LDL cholesterol concentrations slightly and affect the apoA-I to apoB ratio unfavorably compared with oleic acid. Myristic acid is hypercholesterolemic, although less than predicted earlier, and raises both LDL and HDL cholesterol concentrations compared with oleic acid.

Dietary medium-chain triglycerides can prevent changes in myosin and SR due to CPT-1 inhibition by etomoxir

To define determinants of subcellular structures of heart, Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were treated for 5 wk with 15 mg.kg-1.day-1 etomoxir [reduces mitochondrial carnitine palmitoyltransferase-1 (CPT-1) activity and fatty acid synthesis]. To bypass CPT-1 inhibition, etomoxir-treated rats were fed a medium-chain fatty acid (MCFA) diet. Etomoxir induced a proportionate growth of heart, which could partially (WKY, P < 0.05) or completely (SHR, P < 0.05) be prevented by the MCFA diet. Also the etomoxir-induced increase in myosin V1 was partially prevented (P < 0.05). Etomoxir increased (P < 0.05) rate of sarcoplasmic reticulum (SR) Ca2+ uptake of WKY and SHR ventricular homogenates in the presence or absence of the SR Ca2+ release inhibitor ruthenium red. The MCFA diet resulted in SR Ca2+ uptake rates that were in between those of etomoxir-treated and untreated rats. The in vitro 32P incorporation into phospholamban and troponin I did not differ significantly in WKY. Etomoxir induced, however, an increase (P < 0.05) in the phosphorylated intermediate of the Ca2+ adenosinetriphosphatase in WKY that was prevented by the MCFA diet. In SHR, etomoxir increased the in vitro phospholamban phosphorylation, which was reduced compared with WKY. The data show that myosin and SR are affected by a chronically altered substrate utilization of heart.