Browsing by Subject "lipolysis"

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  • Qin, Nanbing; Bayat, Ali-Reza; Trevisi, Erminio; Minuti, Andrea; Kairenius, Piia; Viitala, Sirja; Mutikainen, Mervi; Leskinen, Heidi; Elo, Kari Tapani; Kokkonen, Tuomo Juhani; Vilkki, Johanna (2018)
    To investigate the metabolic (.11, ! in the adipose tissue (AT) of dairy cows under milk fat depression (MFD), 30 cows were randomly allocated to a control diet, a conjugated linoleic acid (CLA)-supplemented diet, or a high-starch diet supplemented with a mixture of sunflower and fish oil (2:1; as HSO diet) from 1 to 112 d in milk. Performance of animals, milk yield, milk composition, energy balance, and blood metabolites were measured during lactation. Quantitative PCR analyses were conducted on the AT samples collected at wk 3 and 15 of lactation. The CLA and HSO diets considerably depressed milk fat yield and milk fat content at both wk 3 and 15 in the absence of significant changes in milk protein and lactose contents. In addition, the HSO diet lowered milk yield at wk 15 and decreased dry matter intake of cows from wk 3 to 15. Compared with the control, both CLA and HSO groups showed reduced body weight loss, improved energy balance, and decreased plasma concentrations of nonesterified fatty acids and beta-hydroxybutyrate at early lactation. The gene expression analyses reflected suppressed lipolysis in AT of the CLA and HSO groups compared with the control at wk 3, as suggested by the downregulation of hormone-sensitive lipase and fatty acid binding protein 4 and the upregulation of perilipin 2. In addition, the HSO diet promoted lipogenesis in AT at wk 15 through the upregulation of 1-acylglycerol-3-phosphate O-acyltransferase 2, mitochondria' glycerol-3-phosphate acyltransferase, perilipin 2, and peroxisome proliferator-activated receptor gamma. The CLA diet likely regulated insulin sensitivity in AT as it upregulated the transcription of various genes involved in insulin signaling, inflammatory responses, and ceramide metabolism, including protein kinase B2, nuclear factor kappa B1, toll-like receptor 4, caveolin 1, serine palmitoyltransferase long chain base subunit 1, and N-acylsphingosine amidohydrolase 1. In contrast, the HSO diet resulted in little or no change in the pathways relevant to insulin sensitivity. In conclusion, the CLA and HSO diets induced a shift in energy partitioning toward AT instead of mammary gland during lactation through the regulation of different pathways.
  • Sekhar, Deepa (Helsingfors universitet, 2012)
    Metabolic disorders are known to predispose dairy cows to periparturient diseases. Main components of metabolic disorder are insulin resistance and severe negative energy balance which are responsible for the reduced fertility in addition of increased risk of disease in dairy cows. The mobilization of adipose tissue in response to energy deficiency is associated with metabolic and endocrine changes during early lactation. Reduced insulin sensitivity in peripheral tissues could potentially change the relative rates of lipolysis and lipogenesis. This study focused on expression of lipogenesis and lipolysis associated genes around parturition. Samples and data sets for this study were obtained from the feeding experiments conducted from September 2010 to April 2011 in Viikki Experimental Farm at the University of Helsinki. Sixteen multiparous Ayrshire cows were divided into two groups based on energy level and fibre content of their feed: (1) grass silage group (control) and (2) silage-roughage mixture group (experiment). During experimental period average energy intake (MJ/day) in silage group was 35% higher than in silage-roughage mixture group. Subcutaneous adipose tissue samples were collected a week before, one day and a week after parturition from cows. Total RNA was extracted from tissue samples quality and quantity of total RNA was analysed using electrophoresis and spectrophotometer. Complementary DNA (cDNA) was prepared from the total RNA for quantitative PCR (qPCR). QPCR was conducted to quantitate expression of the following genes: adiponectin (ADIPOQ), leptin (LEP), peroksisome proliferator activated receptor gamma (PPAR-?), adiponectin receptor-1 (AR1), adiponectin receptor-2 (AR2), lipoprotein lipase (LPL), stearoyl-CoA desaturase (SCD) and hormone-sensitive lipase (HSL). Two genes, AR2 and LEP, were downregulated in group 1. Reduced expression of AR2 in group 1 may relate to an increased insulin resistance. The glucose metabolism was reduced further leading to reduced insulin sensitivity. Lower expression of LEP after parturition indicates usage of energy for milk production. The upregulation of SCD in group 1 before and after calving as well as after calving in group 2 may be a result of the uptake of fatty acids by the mammary tissues. The expression of ADIPOQ, AR1, LPL, PPAR, and HSL did not show any significant changes.
  • Heikintalo, Noora (Helsingfors universitet, 2012)
    The aim of this study was to find out what new characteristics are possible in Emmental with a novel pre-treatment routine of milk. Homogenization of the milk and its consequent impact on lipolysis affect cheese properties was examined. Cheeses (H0, H50 and H100) were produced from milks, which were homogenized at different pressures (0, 50 or 100 bar) and the control cheese was prepared from unhomogenized milk. Cheeses were ripened for three months. Homogenization of milk causes redistribution of milk fat globules into smaller ones. Physical changes to the milk fat globule membrane allow indogenous lipoprotein lipase to access and breakdown triglycerides of milk releasing free fatty acids, known as lipolysis. The sensory quality of the cheeses were studied with traditional descriptive analysis and the modern Temporal Dominance of Sensations (TDS) method. The chemical composition of cheeses were also determined (moisture, salt, fat and protein content). In addition the degree of lipolysis in the milk, from which cheese was made of, was measured by the acid degree value (ADV) and a fluorimetric lipase assay. Homogenization of milk at 50 and 100 bar modified cheese properties most and homogenization of milk with 0 bar pressure less, compared to the control cheese. According to sensory results, the changes in the texture of cheeses were most significant. As a results of homogenization of milk the texture of cheese changed from elastic to crumbly, greasy and sticky. The cheese flavor changed due to homogenization of milk and the consequent lipolysis to become stronger, saltier and more sour. There were no significant differences in intensity of odour attributes between the cheeses. Homogenization of milk (50 and 100 bar) increased the moisture and salt content and reduced protein content. The differences in fat content between the cheeses were small. Homogenization of milk at 50 and 100 bar pressures exposed milk fat to lipolysis, which was seen as an increase in acid degree values of milk. On the other hand, homogenization of milk (50 and 100 bar) decreased lipoprotein lipase activity in the milk according to the fluorimetric assay. However the residual activity of lipoprotein lipase in milk was strong enough to almost double the amount of free fatty acids in homogenized milk. It can be possible to change texture characteristics of cheese by using homogenization of milk as a part of cheese manufacture. Different texture attributes can be utilized in the development of new types of cheese.
  • Qadri, Sami; Lallukka-Brück, Susanna; Luukkonen, Panu K.; Zhou, You; Gastaldelli, Amalia; Orho-Melander, Marju; Sammalkorpi, Henna; Juuti, Anne; Penttilä, Anne K.; Perttilä, Julia; Hakkarainen, Antti; Lehtimäki, Tiina E.; Oresic, Matej; Hyötyläinen , Tuulia; Hodson, Leanne; Olkkonen, Vesa M.; Yki-Järvinen, Hannele (2020)
    Background & Aims The I148M variant in PNPLA3 is the major genetic risk factor for non-alcoholic fatty liver disease (NAFLD). The liver is enriched with polyunsaturated triglycerides (PUFA-TGs) in PNPLA3-I148M carriers. Gene expression data indicate that PNPLA3 is liver-specific in humans, but whether it functions in adipose tissue (AT) is unknown. We investigated whether PNPLA3-I148M modifies AT metabolism in human NAFLD. Methods Profiling of the AT lipidome and fasting serum non-esterified fatty acid (NEFA) composition was conducted in 125 volunteers (PNPLA3(148MM/MI), n = 63; PNPLA3(148II), n = 62). AT fatty acid composition was determined in 50 volunteers homozygous for the variant (PNPLA3(148MM), n = 25) or lacking the variant (PNPLA3(148II), n = 25). Whole-body insulin sensitivity of lipolysis was determined using [H-2(5)]glycerol, and PNPLA3 mRNA and protein levels were measured in subcutaneous AT and liver biopsies in a subset of the volunteers. Results PUFA-TGs were significantly increased in AT in carriers versus non-carriers of PNPLA3-I148M. The variant did not alter the rate of lipolysis or the composition of fasting serum NEFAs. PNPLA3 mRNA was 33-fold higher in the liver than in AT (P <.0001). In contrast, PNPLA3 protein levels per tissue protein were three-fold higher in AT than the liver (P <.0001) and nine-fold higher when related to whole-body AT and liver tissue masses (P <.0001). Conclusions Contrary to previous assumptions, PNPLA3 is highly abundant in AT. PNPLA3-I148M locally remodels AT TGs to become polyunsaturated as it does in the liver, without affecting lipolysis or composition of serum NEFAs. Changes in AT metabolism do not contribute to NAFLD in PNPLA3-I148M carriers.