Fatty Acid-binding Protein Activity Research Articles

Diet, Obesity, and Asthma.

Obesity has reached epidemic proportions in many developed countries as Western dietary patterns have been widely adopted. These diets are characterized by excess energy intake as well as regular consumption of processed or "fast" foods and limited consumption of fruit, vegetables, and whole grains. The result is a high intake of saturated fat, refined carbohydrates, and sodium; and a low intake of fiber, vitamins, and other phytochemicals. This type of poor-quality diet has been associated with increased risk of chronic inflammatory diseases, including asthma. Of particular note, high intake of saturated fat stimulates proinflammatory pathways via activation of pattern recognition receptors, endoplasmic reticulum stress, and fatty acid-binding protein activity. Conversely, with a low intake of soluble fiber, beneficial antiinflammatory mechanisms, such as free fatty acid receptor activation and histone deacetylase inhibition, are suppressed. Similarly, with a low intake of antioxidants such as vitamin C, vitamin E, and carotenoids, nuclear factor κ-light-chain-enhancer of activated B cells activity is enhanced, creating a proinflammatory environment. There is evidence derived from human and experimental models of asthma suggesting that these mechanisms contribute to the development of airway inflammation, loss of asthma control, and/or worse lung function. Obese individuals have increased asthma morbidity and reduced quality of life, so strategies for better management of these patients are urgently needed. Evidence suggests that, in addition to reducing the quantity of food consumed, interventions should also target the quality of food consumed to improve both asthma management and the overall health and well being of these patients.

The ontogeny of fatty acid-binding protein in turkey (Meleagridis gallopavo) intestine and yolk sac membrane during embryonic and early posthatch development

Experiments were conducted to confirm the existence and ontogeny of fatty acid binding protein (FABP) in the intestine and yolk sac membrane of turkey poults (Meleagridis gallopavo) during embryonic and early posthatch development. Intestinal (I-) FABP was measured using an immunoblot procedure incorporating anti-chick liver (L-)FABP antisera. FABP activity in both tissues was also confirmed with a ligand-binding assay incorporating 14C-oleic acid. I-FABP did not cross-react with chick L-FABP antisera until hatch, embryonic day 28 (ED 28), after which there was a 39% increase in I-FABP concentration through the first 3 d posthatch (PD 3). FABP concentration calculated on a total intestinal basis (ng/intestine), however, increased 10-fold through PD 6. Specific activity [disintegrations per minute (dpm)/ mg cytosolic protein] was greatest at hatch and decreased slightly thereafter, whereas specific activity of FABP in the yolk sac membrane peaked between ED 16 and ED 19 and then declined. Total yolk sac activity (dpm/yolk sac membrane), however, plateaued at ED 22 before declining to low levels by PD 3, coincident with the period of maximal lipid transfer out of the yolk.

The development of an immunoblotting assay for the quantification of liver fatty acid-binding protein during embryonic and early posthatch development of turkeys (Meleagridis gallopavo)

Turkey (Meleagridis gallopavo) liver cytosolic fatty acid binding protein (FABP) was purified and used as a standard for quantification. An immunoblotting procedure was developed to study the ontogeny of liver cytosolic FABP during embryonic and early posthatch development in turkey poults. Liver FABP activity was also determined indirectly through the use of gel filtration chromatography followed by a ligand-binding assay. The specific activity of liver FABP (ng/mg of cytosolic protein) increased with length of incubation, peaking initially at Day 22, declining between Days 22 and 25, and increasing again from hatch (Day 28) to 6 d posthatch. The specific activity of liver FABP increased 12-fold between Day 13 of incubation and 6 d posthatch compared with total activity, which increased from 946 to 1.01 × 10(6) ng/liver during the same period, a 1,067-fold increase. The results from both analytical procedures were similar, suggesting that the immunoblot method could be used to quantify liver FABP concentrations. The observed increases in FABP activity throughout the embryonic period and first days after hatching paralleled increases in liver lipid concentration. Therefore, liver FABP may be associated with hepatocyte fatty acid transport and metabolism during the latter stages of incubation and early posthatch period.

Dietary clofibric acid increases intestinal fatty acid binding protein activity and apparent lipid digestibility in weanling swine.

The effects of supplementation of dietary clofibric acid (.5% wt/wt) on fatty acid binding protein (FABP) activity, apparent lipid digestibility, and serum cholesterol concentrations were evaluated in weanling pigs. Twenty-four barrows were allotted by weight and litter to a randomized complete block design with two treatments (basal vs clofibric acid) in six replicates. Nutrient digestibility measurements were made for a 2-wk period, after which the pigs were killed and tissues were collected. No differences in BW, liver, proximal small intestine, distal small intestine, and proximal and distal intestinal mucosa weights were observed. Apparent lipid digestibility was greater (P < .05) for the overall 2-wk period in clofibric acid-supplemented pigs (81.5 vs 76.6%). This paralleled the increased FABP activity in the distal small intestine (P < .001) of clofibric acid-supplemented pigs. Proximal intestine and liver FABP activities were unaffected by dietary treatment. Serum cholesterol concentrations were markedly lowered by clofibric acid supplementation. During wk 1, pigs fed the basal diet had twofold greater (P < .01) serum cholesterol concentrations, whereas during wk 2, basal-fed pigs had fourfold greater (P < .01) serum cholesterol concentrations (81.5 vs 18.3 mg/dL). These results suggest that elevated intestinal FABP activities may augment fatty acid absorption from the gastrointestinal tract.

Perinatal ontogeny of fatty acid binding protein activity in porcine small intestine

Growth and functional maturation of porcine small intestine was characterized in relation to stage of perinatal development. Fatty acid binding activity of specific low molecular weight, cytosolic proteins (FABPs) was measured in the small intestinal mucosae of young pigs. Intestinal mucosa mass, soluble protein content, DNA content and oleic acid-binding capacity were determined for pigs (n=4) at −4, 2, 4, 7, 14, 22, 28 and 35 days of age. FABP activity of mucosa from the proximal half of intestine displayed a cubic pattern of change (P<.01) with age, increasing from 15.2 nmol oleic acid bound at −4 days to 542.1 nmol bound at 14 days. Oleic acid-binding decreased to 240 nmol at 22 days (day 1 postweaning) but remained elevated above preweaning values at day 28. Distal-region small intestinal FABP activity corresponded to 13.5 nmol oleic acid bound at −4 days, increased to 124.3 nmol bound at day 7, and decreased to 103.0 nmol bound at day 14. Immediately postweaning, distal-region intestinal FABP activity increased three-fold relative to the day 14 values. Proximal intestine FABP activities exceeded distal intestine activities for all days except at day 22. Total FABP activity, adjusted per mg DNA, exhibited a nine-fold increase in the proximal region of the small intestine between −4 days and day 7. The developmental variation in intestinal FABP activity suggests that FABPs may represent markers of neonatal intestinal differentiation and lipid absorptive capacity in the neonate.

Temporal evaluation of fatty acid-binding protein (FABP) activity in association with the development of atherosclerosis in the rabbit

1. 1. The relationship between atherosclerosis development and changes in arterial fatty acid binding protein (FABP) activity was investigated in the aortas of New Zealand rabbits which were fed an atherogenic diet containing 1% cholesterol and 3% peanut oil for 16 weeks. 2. 2. At 4-week intervals, FABP activity, cholesterol and microsomal acylCoA: cholesterol acyltransferase (ACAT) activity were determined in aortic tissue and serum cholesterol was measured; age-matched normal rabbits served as control comparators. 3. 3. Serum cholesterol increased from 35mg/dl in the normal rabbits to 2290 mg/dl in the 16-week cholesterol-fed rabbits. 4. 4. The microsomal fraction isolated from cholesterol-fed rabbit aortas exhibited a progressive elevation in ACAT activity as time on the diet increased. By 12–16 weeks, ACAT activity had increased approximately 10-fold relative to normal activity. 5. 5. Arterial cholesterol content of the cholesterol-fed animals increased from less than 2 mg/g wet weight to greater than 10 mg/g wet weight at 12 and 16 weeks. In contrast, arterial FABP activity gradually decreased with time on the cholesterol diet; a significant decrease ( P < 0.05) was observed at 16 weeks, where palmitoyl CoA binding was decreased from 61.0 to 36.3pmol/mg protein. 6. 6. In the cholesterol-fed rabbits, total arterial cholesterol and ACAT activity showed a significant ( P < 0.05) inverse correlation to FABP activity with correlation coefficients of −0.93 and −0.95, respectively. 7. 7. Additionally, FABP activity increased significantly ( P < 0.05) in the 16-week normal rabbit as compared to the 4-week normal rabbit, suggesting an age-dependent interaction.

Relationship between fatty acid-binding protein activity and marbling scores in bovine longissimus muscle.

Studies were conducted in an attempt to establish a relationship between fatty acid-binding protein (FABP) activity and marbling score in bovine longissimus muscle. Longissimus muscle was obtained from four 20-mo-old Charolais-Hereford crossbred heifers, three 16-mo-old Angus steers, and four 18-mo-old Angus steers. Immediately after slaughter, longissimus muscles were removed for the extraction of FABP. Supernatant (S104) fractions containing 41.3 to 144 mg of protein (depending on animal group) were eluted over Sephadex columns, and elution fractions were analyzed for the binding of radiolabeled palmitoyl-coenzyme A (CoA). Specific activities of FABP were 23, 32, and 101 nmol palmitoyl-CoA bound/mg protein for the Charolais-Hereford, 16-mo-old Angus, and 18-mo-old Angus cattle, respectively. These preliminary results suggested that longissimus muscle FABP activity was positively correlated with marbling score. To test specifically for this possibility, longissimus muscle was obtained at slaughter from each of four Wagyu steers, Angus heifers and Braford heifers. Marbling scores taken at the 12th-13th rib junction were Sm45, Sm43, and SI50 for the Wagyu, Angus, and Braford cattle, respectively. Interfascicular adipose tissue was exhaustively removed from sections of the 5th to 8th thoracic region of the longissimus muscle to eliminate any contribution of adipose tissue to FABP activity. For each animal, 300 mg of the S104 were eluted over Sephadex columns. Specific activities for the Wagyu, Angus, and Braford longissimus muscle FABP were 3.1, 3.8, and 3.9 pmol palmitoyl-CoA bound/mg protein, respectively, and were not different (P greater than .05) among the three animal groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation, characterization, and developmental expression of pig intestinal fatty acid-binding proteins

The goal of this study was to characterize and quantify intestinal fatty acid-binding proteins of the pig. Small intestinal mucosa from 13–19 kg pigs was homogenized and centrifuged to obtain cytosol. Isolation of fatty acid-binding proteins from delipidated cytosol was achieved using molecular sieve, oleic acid affinity, and ion exchange chromatography. Fatty acid-binding protein isolation was monitored using a fatty-acid binding assay in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Antisera to rat liver-fatty acid-binding protein cross reacted with an isolated intestinal fatty acid-binding protein of M r = 13,000, whereas antisera to rat intestine-fatty acid-binding protein was not cross reactive with isolated pig intestinal proteins. These experiments identify a pig intestinal fatty acid-binding protein that exhibits strong immunochemical similarity to rat liver-fatty acid-binding protein. Cytosol prepared from intestinal mucosa of pigs at −4, 2, 4, 7, 15, 22, 28, and 35 d of age was assayed for fatty acid-binding protein activity. Preweaning fatty acid-binding protein activity in cytosol was maximal at 7 days of age when expressed as total jejunal fatty acid binding per kilogram bodyweight, intestinal or mucosal weight or milligram total protein. After weaning (21 d), fatty acid-binding protein activities declined to 28 days, but increased again by 35 days. Total soluble fatty acid-binding protein activity in pig intestine is regulated during postnatal development and this may account in part for the altered intestinal absorption of lipids observed in young pigs at weaning.

Arterial fatty acid-binding protein activity associated with dietarily-induced and spontaneously occurring atherosclerosis in the rabbit ( Oryctolagus cuniculus)

1. 1. Adult WHHL rabbits, or New Zealand rabbits fed either a stock chow diet or a high cholesterol diet were evaluated to assess the relationship between the development of aortic atherosclerosis and arterial FABP activity. 2. 2. Aortic FABP activity was significantly ( P < 0.05) lower in atherosclerotic New Zealand aortas ( 0.039 ± 0.008 nmol palmitoyl CoA bound/mg soluble prot) which had developed macroscopic lesions on 80% of the aortic surface as compared to lesion-free New Zealand aortas ( 0.053 ± 0.002 nmol palmitoyl CoA bound/mg soluble prot). 3. 3. In spontaneously hyperlipidemic rabbit (WHHL) aortas, FABP activity ( 0.023 ± 0.004 nmol palmitoyl CoA bound/mg soluble prot) was significantly lower ( P s ̌ 0.05 ) than in either the normal or atherosclerotic New Zealand aortas. 4. 4. To our knowledge, this study is the first to report a change in arterial FABP with the atherogenic process.

Lipid Synthesis and Adipocyte Growth in Adipose Tissue from Sheep Chronically Fed a Beta-Adrenergic Agent

The effects of the chronic ingestion of the beta-adrenergic agonist clenbuterol on ovine sc adipose tissue were investigated. Three groups of 10 wether lambs with an average initial weight of 22.7 kg were used as experimental animals. After culling 2 to 3 animals per group, one group of eight sheep was slaughtered (initial). The remaining two groups of sheep (control, n = 7 and clenbuterol-fed, n = 8) were fed either a control, high-energy diet or one containing 2 ppm clenbuterol for 40 to 44 d. At slaughter, sc adipose tissue was obtained from all animals for assays in vitro. Subcutaneous fat accretion observed over time in the control sheep was due primarily to an increase in the number of lipid-filled adipocytes. This phenomenon was not observed in the clenbuterol-fed sheep. The incorporation of acetate into lipid increased in the clenbuterol-fed group relative to the initial group and was numerically greater than the rate observed for the control group. Similar results were observed for lipogenic enzyme activities and fatty acid-binding protein activity. Palmitate esterification in vitro tended to be elevated in the clenbuterol-fed group, relative to the control group, suggesting increased triacylglycerol turnover. The in vitro data indicate that clenbuterol did not decrease sc fat accretion in sheep by inhibiting lipogenesis.

Adipose tissue, longissimus muscle and anterior pituitary growth and function in clenbuterol-fed heifers.

The present study was conducted to determine the effects of feeding clenbuterol on adipose tissue and longissimus muscle growth in heifers. For 50 d, 14 heifers were fed either a sucrose-based, clenbuterol supplement or a placebo in which the clenbuterol had been omitted. The heifers were slaughtered in two groups, based on initial weight. Adipose tissue from several anatomical sites and longissimus muscle (depending on slaughter group) were obtained fresh at slaughter. Changes in carcass characteristics elicited by clenbuterol were similar to those reported by others for steers and sheep. Subcutaneous (sc) and intramuscular (im), but not perirenal, adipocytes were smaller and there were more cells per g tissue in the adipose tissue depots of the clenbuterol-fed heifers. Clenbuterol decreased lipogenic enzyme activities, fatty acid-binding protein activity, basal lipolysis and acetate incorporation into glyceride-fatty acids (P less than .05) in sc adipose tissue, but had no effect (P greater than .05) on lipogenesis or lipolysis in im adipose tissue. Clenbuterol elicited a 20% increase in type II myofiber diameters (P less than .05) but had no effect on type I myofiber diameters. In vitro growth hormone release by perifused anterior pituitaries was not affected significantly by long-term in vivo exposure to clenbuterol. These data indicate that a depression in lipogenesis is the mechanism by which clenbuterol decreases subcutaneous fat accretion in cattle.

Fatty Acid-Binding Protein Activity in Tissues from Pigs Fed Diets Containing 0 and 20% High Oleate Oil

Eight pigs (four sets of littermates) were allotted to either a control sorghum-soybean meal diet or a test diet containing 20% canola oil. The pigs were slaughtered at approximately 100 kg live weight. Subcutaneous adipose tissue, longissimus dorsi muscle and liver samples were collected immediately after slaughter. Fatty acid-binding protein (FABP) was measured in 104,000 × g supernatant fractions. Characterization of the FABP assay with liver supernatants indicated that FABP exhibited sigmoidal kinetics, with an apparent Kd of 0.75 µm. Doubling the protein amount in the assay did not affect the FABP activity. FABP was demonstrated in liver, with an activity of 3448 pmol bound/g liver, and in adipose tissue, with an activity of 276 pmol bound/g adipose tissue. No activity was observed in the muscle tissue. FABP activity of liver and adipose tissue from swine fed 20% canola oil was higher on a per gram tissue basis than that in tissues from pigs fed the control diet.

Influence of Age on Utilization of Supplemental Fats by Young Turkeys

Male poults were fed diets containing 0, 4, 8, or 12% tallow or 4, 8, or 12% animal-vegetable fat blend (A-V Fat) from 1 day to 8 weeks of age. Supplemental fat improved 8-week body weight and feed efficiency, irrespective of fat source. Fat retention (fat consumed-fat excreted) was not affected by fat level or by fat source after 2 weeks of age. At 2 weeks, fat retention by poults fed tallow was less than that of poults fed A-V Fat. Fat retention increased with age, irrespective of fat source or level. Fat retentions ranged from 66.4 to 83.7 at 2 weeks and from 90.8 to 96.5 at 8 weeks of age. Changes in metabolizable energy (ME) values of the fats with age paralleled those of fat retention, whether ME were estimated by multiplying fat retention percentages times gross energy of the fats or by regression analysis of changes in diet ME associated with increments of fats. On the basis of changes in diet ME, the ME of tallow was 6808 kcal/kg at 2 weeks and 8551 kcal/kg at 8 weeks. Analagous values for A-V Fat were 7114 and 8924 kcal/kg, respectively. Fatty acid analysis of dietary and excreta fat indicated that, as turkeys aged, improvements in retention were greatest for palmitic and stearic acids, especially in the instance of tallow. Fatty acid binding protein (FABP) assay of intestines from poults fed no added fat, 12% tallow, or 12% A-V Fat showed that fat level did not significantly affect FABP activity. There was, however, a marked increase in intestinal FABP in 6- and 8-week-old poults as compared with 2- or 4-week-old poults.

Fatty Acid-Binding Protein Activities in Bovine Muscle, Liver and Adipose Tissue

Subcutaneous adipose tissue, sternomandibularis muscle and liver were obtained from steers immediately postmortem. Muscle strips and adipose tissue snips were incubated with 0.75 mM [1-14C]palmitate and 5 mM glucose. Muscle strips esterified palmitate at the rate of 2.5 nmol/min per gram tissue, which was 30% of the rate observed for adipose tissue. Fatty acid-binding protein activity was measured in 104,000 × g supernatant fractions of liver, muscle and adipose tissue homogenates. Muscle and adipose tissue fractions bound 840 and 140 pmol [1-14C]palmitoyl-CoA per gram tissue, respectively. Fatty acid-binding protein activity was greater in adipose tissue than in muscle when data were expressed per milligram protein (35 vs. 13 pmol palmitoyl-CoA bound per milligram of soluble protein, respectively). Fatty acid binding-protein activity was correlated with the rate of palmitate esterification within each tissue. Liver contained the highest fatty acid-binding protein activity (13,000 pmol palmitoyl-CoA bound per gram tissue and 215 pmol palmitoyl-CoA bound per milligrams soluble protein).

Digestion and Absorption of Lipids in Poultry

Ingested lipids undergo intestinal emulsification, digestion, micellar solubilization, cell membrane permeation, intracellular esterification and incorporation into lipoproteins before release to the interstitial fluid. Bile salts secretion, essential to both emulsification and micelle formation in the intestine, has been found to be influenced by quantity and quality of dietary lipids and by other emulsifiers. Modifications of dietary lipid contents cause changes in pancreatic lipase content and secretion. Colipase secretion by the pancreas seems dependent on both lipid and protein intakes. Intracellular processes essential for lipid absorption increases in rate as lipid intake increases. Bile salts seem to play important roles as moderators of these processes. The ability to digest lipids is not fully developed in the newly hatched poultry. Addition of bile salts, lipase or phospholipids to chick diets improves the digestibility of animal fats, demonstrating that lipid digestive processes are not fully functional in the very young. Physiological studies support these indications. Lipase concentration in pancreatic tissue and intestinal contents of poultry increases severalfold during the first few weeks after hatch. Similar changes with age have been observed in bile salt secretion. The development in enterocytes of fatty acid-binding protein activity seems to parallel the development in lipase activity and bile salt secretion in poultry.