Yield of human adipose-derived adult stem cells from liposuction aspirates.

BACKGROUND: Primary cultures of isolated human adipose-derived adult stem (ADAS) cells are multipotent and differentiate in vitro along the adipocyte, chondrocyte, neuronal, osteoblast, and skeletal muscle pathways. METHODS: We examined the ADAS cell yield per unit volume of liposuction tissue, and their surface protein phenotype by flow cytometry. Adipogenesis was assessed by Oil Red O staining and ELISA analysis of leptin secretion. RESULTS: The donor population was 87.5% female (n=18) with a mean age (+/-SD) of 44+/-10 years and body mass index (BMI) of 24.9+/-2.7. The mean cell yield was 404 000+/-206 000 cells per milliliter of lipoaspirate (n=18). Linear regression analysis of the cells derived from the female donors demonstrated a significant negative correlation between the number of cells obtained per milliliter of lipoaspirate with the BMI but not the age of the donor. The undifferentiated ADAS cells were homogeneously positive for the cell-surface markers CD10, CD13, CD29, CD44, CD49e, CD59, CD90, and HLA-ABC, and homogeneously negative for the cell surface markers CD11b, CD45, and HLA-DR. The absence of the panhematopoietic marker, CD45, indicates that the ADAS cells do not derive from circulating BM hematopoietic stem cells. Adipocyte differentiation led to a 5.1-fold increase in Oil Red O staining, and a 196-fold increase in leptin secretion levels. Culture of the cells in the presence of antibiotic and fungizone did not alter the undifferentiated ADAS cell immunophenotype based on flow cytometry, or their adipocyte differentiation based on leptin secretion. DISCUSSION: The ability to isolate a consistently homogeneous population of undifferentiated adult stem cells from adipose tissue of multiple donors supports their potential utility in future tissue-engineering applications.

Estimation of available energy of dietary fibres by indirect calorimetry in rats.

BACKGROUND: Knowledge of energetic availability of dietary fibres is important for human nutrition. But up to now results are often different and depend on the methods used. Estimation of metabolisable energy of dietary fibres (mainly by balance technique) is a time-consuming procedure and needs special technical effort. AIM OF THE STUDY: Validation of the experimental design for short-term studies by using indirect calorimetry with feeding below maintenance requirement to evaluate the energetic availability of dietary fibres and their influence on absorption velocity of carbohydrates (CHO). METHODS: Energy expenditure and CHO oxidation (including short-chain fatty acids as fermentation products) were estimated in Wistar rats over 23 h after being fed a basal diet for the first day (300 KJ/kg0.75, 20% protein, 3% fat, 77% CHO) followed by supplementation with either microcrystalline cellulose, the soluble rye fibre arabinoxylan, apple pectin, amylomaize starch (with 48% of resistant starch) or gelatinised wheat starch (200 KJ/kg0.75 each) as control for the following days. Energetic availability was determined by comparing the increase of CHO oxidation after addition of gelatinised wheat starch with that of the dietary fibres tested. RESULTS: In comparison to wheat starch (100%), the following energetic availability of the dietary fibres was found: microcrystalline cellulose 14%, arabinoxylan 33%, pectin 39%, amylomaize starch 62%. The time-course of CHO oxidation indicated that microcrystalline cellulose enhances, whereas the soluble rye fibre slows down the velocity of CHO absorption due to the different consistency of the intestinal contents modified by the kind and properties of the used dietary fibres. After intake of arabinoxylan or pectin, CHO oxidation remained at a higher level during the experimental period elucidating an increased activity of fermentation to short-chain fatty acids. CONCLUSIONS: Short-term experiments in rats using indirect calorimetry are a suitable method for comparative estimation of the energetic availability of dietary fibres. Results are partly in agreement with values estimated by long-term in vivo methods.

Energy expenditure and substrate oxidation rates of obese rats during a 12-day treatment with dexfenfluramine.

Serotoninergic neuronal networks are included in regulation and modification of eating behavior and energy metabolism. Dexfenfluramine (dF), a serotonin releaser and reuptake inhibitor, was used to investigate changes in food intake, body weight development, energy expenditure, respiratory quotient, and substrate oxidation rates for 12 days. Rats which had been made obese by postnatal overfeeding received an energy-controlled mash diet and water ad libitum and were intraperitoneally injected with either saline or 5 or 10 mg dF/kg. As compared with controls, food intake and energy expenditure were significantly decreased in a dose-dependent manner, especially during the first 6 days. Lipid oxidation was increased, while the oxidation of carbohydrates was decreased. The body weight was only slightly reduced after 2 days of dF treatment. After 4 days, dF-treated rats resumed body weight, but as compared with controls both dF groups exhibited lower body weights at the end of the experiment. After 12 days the plasma glucose concentration was unchanged, whereas plasma free fatty acids were significantly decreased. Plasma insulin levels were unchanged after dF, but 10 mg dF/kg led to increased muscle and, especially liver glycogen contents, indicating an improved nonoxidative glucose disposal. Muscle pyruvate kinase was slightly but not significantly increased after dF treatment but that of the liver was significantly decreased, indicating a reduced glycolytic activity of the liver. Whereas the renal N excretion was rather decreased, the plasma concentrations of urea, citrulline, arginine, and ornithine were increased, and the liver contents of glutamine and arginine were decreased. Possibly, there is a shift of ammonia removal from glutamine synthesis to production of urea. The sum of all large neutral amino acids in muscle was significantly decreased after dF treatment, indicating a diminished proteolysis. Pair-feeding experiments over 2 days revealed that this was not solely a result of diminished food intake, but also an additional metabolic effect of dF, different from its anorectic effect. It is concluded that both increased oxidation of endogenous fat and reduced food intake could mediate the body weight reducing effect of dF.

Energy metabolism and metabolite patterns of rats after application of dexfenfluramine.

Serotoninergic neuronal networks are important for food intake and body weight regulation. However, the mechanisms by which some metabolic pathways are influenced are rather unclear. Dexfenfluramine (DF), a serotonin releaser and re-uptake inhibitor, was used to investigate changes in food intake, body weight development, energy expenditure, respiratory quotient and substrate oxidation rates for 12 days. Normal rats, receiving an energy-controlled mash diet and water ad libitum were intraperitoneally injected daily with either saline, 1, 2.5, 5 or 10 mg DF/kg. Compared to controls, food intake, body weight development and energy expenditure were decreased in a dose-dependent manner, especially during the first six days. Lipid oxidation was increased while oxidation of carbohydrates was decreased. Pair-feeding experiments over three days revealed that this was a clear pharmacological effect and not simply a result of diminished food intake. At the end of these experiments, plasma glucose and liver and muscle glycogen were unchanged after DF, but isoleucine, leucine and lysine were significantly decreased in plasma and liver. Therefore, the plasma tryptophan/large neutral amino acids ratio was slightly increased. Protein oxidation was unchanged after DF. It is concluded that a prompt decline in energy expenditure with increased fat oxidation rates could mediate the body weight reducing effect of DF.

Postprandial thermogenesis of rats with glutamate induced obesity in relation to energy intake.

Postprandial thermogenesis was estimated in 4-month-old male rats with glutamate induced obesity after being fed with 300, 450 and 600 kJ/kg0.75 of a pellet diet, respectively by indirect calorimetry in computer-controlled open circuit metabolic cages over 8 h. After an intake of 600 kJ/kg0.75 (above the maintenance energy requirement) postprandial thermogenesis was significantly reduced in the obese animals to about 40% of control rats (12.0 versus 31.5 kJ/kg0.75 x 8h). It is concluded that the glutamate obese rat can be accepted as an animal model with impaired facultative thermogenesis, mainly caused by a reduction of sympathetic adrenergic activity.

Evaluation of calcium magnesium acetate and road salt for contact hypersensitivity potential and dermal irritancy in humans.

Calcium magnesium acetate (CMA) and road salt are both de-icing agents to which workers may be dermally exposed. A commercial formulation of CMA (Chevron Ice-B-Gon Deicer) and road salt were tested in a human repeat insult patch test to evaluate the contact hypersensitivity potential of these materials and to evaluate irritation following single or multiple applications. 72 of the initial 82 panelists completed the study. CMA and road salt (each at 10% and 30% w/w in distilled water; 0.3 ml) were administered under occlusive patches on the forearm for 14 h 3 x per week for 3 weeks. The panelists were challenged 2 weeks later; 2 panelists who had mild reactions were subsequently rechallenged 6 weeks later. Neither CMA nor road salt produced contact hypersensitivity in any panelists. Following the first application, moderate acute irritation was observed only at 1 skin site exposed to 30% road salt. Repeated exposure to CMA or road salt produced mild to moderate irritation. The highest incidence of moderate irritation was observed with 30% road salt. Thus, neither material is expected to cause significant dermal effects in exposed workers. CMA is expected to cause dermal irritation equivalent to or less than that caused by road salt.

Influence of early postnatal overnutrition of rats on fatty acid composition of membrane lipids.

The influence of early postnatal overnutrition on fatty acid composition of erythrocyte, thrombocyte and liver mitochondria membrane lipids was studied in male rats (3, 6 and 11 months old) reared in small nests (2 pups per dam) in comparison to normally bred rats (12 pups per dam). Independent of age elevated proportions of palmitic and stearic acid at the expense of linoleic and arachidonic acid were found in all membrane lipids investigated in the postnatally overfed animals. These changes are discussed in relation to the enhanced lipogenesis with increased body fat accumulation in this animal model of a dietary induced obesity.

Objective measurement of surfactant irritation by fiber optic spectroscopy.

Erythema caused by occlusion of 3 concentrations of surfactant was quantified in vivo using a modified spectrophotometer. Standard chamber irritation test sites were evaluated objectively using the spectrophotometer and subjectively by trained observers. There was a good relationship between the instrumental and visual evaluations. The spectrum was analyzed and a region was chosen to optimize the sensitivity of the method.

[The metabolism of various acaloric compounds with fatlike properties in rats]. / Orientierende Untersuchungen zum Stoffwechsel verschiedenartiger akalorischer Verbindungen mit fettähnlichen Eigenschaften bei der Ratte.

Pseudofats as total substituted long-chain esters and ethers of polyhydroxyl compounds (sucrose, triglycerol, and polyethyleneglycol) are more or less indifferent against gastrointestinal enzymes, but display specific metabolic effects on lipid metabolism especially on cholesterol synthesis in liver, plasma lipid level, and fecal cholesterol excretion. Among the different tested compounds there exist similarities as well as differences, which are to consider as an indication for a specific relationship between structure and effect. These relations are more closely investigated and critically discussed.

Studies on the postprandial thermogenic action of proteins and protein mixtures in rats.

The postprandial thermogenic action of different proteins and their mixtures dependent on their biological value was estimated in rats by indirect calorimetry with special reference to the reproducibility of the evaluation of the postprandial metabolic rate. The absolute thermogenic action (related to the food energy intake) of casein, white-egg protein and gelatine, fed in combination with wheat starch (1:1), amounted to 11.4%, 14.5% and 17.8%, respectively. Mixtures of casein with gelatine (ratio 1:1 and 1:2) as well as the mixture of casein with glycine (in such amount as in the casein-gelatine mixture of 1:1) lead to a postprandial thermogenic action of 16.1%, 19.2% and 14.5%, respectively. If proteins of distinctly different biological value are compared an inverse correlation to their postprandial thermogenic action can be demonstrated which reflects partly theoretical approaches to the ATP yielding capacity, calculated from the amino-acid pattern of the proteins and their mixtures.

The influence of early postnatal overnutrition on peripheric thyroxine metabolism in rats.

The influence of postnatal overnutrition on thyroid metabolism in later life was studied in male rats reared in small nests (2 pups per dam). At an age of 3 months postnatally overfed rats differ from normally bred rats (12 pups per dam) by a significant higher thyroxine and lower triiodothyronine concentration in plasma. Kinetic data of thyroxine metabolism point out a lower fractional turnover rate and a lower metabolic clearance rate per 100 g body mass corresponding with a reduced 131I-uptake by the thyroid gland. A lower energy intake per metabolic mass unit and a lower energy need for maintenance in postnatally overfed rats calculated from intake and body mass development are discussed in respect of correlations between changes of thyroid hormone metabolism and efficiency of energy utilization.

In vivo incorporation of C14-1-acetate into liver and plasma lipids of postnatally overfed rats.

Postnatal overnutrition due to breeding of rats in small nests (4 pups per dam) leads to distinct metabolic changes in later life stages even in conditions of ad libitum feeding. At an age of 5 months rats from small nests differ from those of large nests (14 pups per dam) in a significant higher level of liver triglycerides and cholesterol esters, whereas changes in plasma lipids concern only the increased cholesterol ester fraction. The relative distribution of in vivo incorporated C14-1-acetate into liver lipids shows a higher moiety in the triglyceride fraction of animals from small nests but no changes of the relative distribution of activity among lipid fractions of plasma. These changes of lipid metabolism are discussed in relation to the development of an obese state of postnatally overfed animals.

[Effect of long-time supply of medium-chain triglycerides on postprandial lipid metabolism and fatty acid pattern of membrane lipids in rats]. / Die Wirkung einer langfristigen Zufuhr mittelkettiger Triglyceride auf den postprandialen Lipidstoffwechsel und das Fettsäurespektrum von Membranlipiden bei der Ratte.

To characterize the effect of long-term supply medium-chain triglycerides on the lipid metabolism, the authors determined under postprandial conditions the ratio between the ketone body concentrations in the blood and the liver, the in vitro fatty-acid synthesis in the liver and the adipose tissue, the plasma and liver lipids and the fatty-acid and phospholipid spectra of the plasma and the erythrocytic, thrombocytic and liver mitochondrial membranes, in rats after 9 weeks on an isoenergetic diet containing 12% of medium-chain triglycerides or lard. The long-term supply of medium-chain triglycerides induced a 3-fold increase of the fatty-acid synthesis in the liver and the fatty tissue. In contrast to this, no differences in the concentrations of acetacetate and beta-hydroxybutyrate were detected in the liver and the adipose tissue. The triglyceride and cholesterol contents in the liver were significantly reduced. In spite of the increase of palmitic acid proportion as the end product of the de novo fatty-acid synthesis in the plasma lipids and the erythrocytic membrane, the proportion of essential fatty acids in the membrane lipids under study was not affected; the simultaneous supply of 3% of sunflower oil meets the requirements for essential fatty acids.