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Dekker PM, Boeren S, Saccenti E, Hettinga KA. Network analysis of the proteome and peptidome sheds light on human milk as a biological system. Sci Rep 2024; 14:7569. [PMID: 38555284 PMCID: PMC10981717 DOI: 10.1038/s41598-024-58127-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 03/26/2024] [Indexed: 04/02/2024] Open
Abstract
Proteins and peptides found in human milk have bioactive potential to benefit the newborn and support healthy development. Research has been carried out on the health benefits of proteins and peptides, but many questions still need to be answered about the nature of these components, how they are formed, and how they end up in the milk. This study explored and elucidated the complexity of the human milk proteome and peptidome. Proteins and peptides were analyzed with non-targeted nanoLC-Orbitrap-MS/MS in a selection of 297 milk samples from the CHILD Cohort Study. Protein and peptide abundances were determined, and a network was inferred using Gaussian graphical modeling (GGM), allowing an investigation of direct associations. This study showed that signatures of (1) specific mechanisms of transport of different groups of proteins, (2) proteolytic degradation by proteases and aminopeptidases, and (3) coagulation and complement activation are present in human milk. These results show the value of an integrated approach in evaluating large-scale omics data sets and provide valuable information for studies that aim to associate protein or peptide profiles from biofluids such as milk with specific physiological characteristics.
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Affiliation(s)
- Pieter M Dekker
- Food Quality and Design Group, Wageningen University and Research, Wageningen, 6708 WE, The Netherlands
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, 6708 WE, The Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, 6708 WE, The Netherlands
| | - Edoardo Saccenti
- Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, 6708 WE, The Netherlands
| | - Kasper A Hettinga
- Food Quality and Design Group, Wageningen University and Research, Wageningen, 6708 WE, The Netherlands.
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2
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Relationship between Plasma Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Level and Proteome Profile of Cows. Animals (Basel) 2022; 12:ani12121559. [PMID: 35739894 PMCID: PMC9219453 DOI: 10.3390/ani12121559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/02/2022] [Accepted: 06/14/2022] [Indexed: 11/16/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic and multifunctional neuropeptide; it takes part in the regulation of various physiological processes, such as feeding, reproduction, catecholamine synthesis, thermoregulation, motor activity, brain development and neuronal survival. Since PACAP plays important regulatory roles, we hypothesized that the level of PACAP in blood is associated with expression of other proteins, which are involved in different metabolic pathways. The objective of the present study was to compare plasma protein profiles of cows with high and low plasma PACAP levels. Differential proteome analyses were performed by two-dimensional gel electrophoresis (2D-PAGE) followed by tryptic digestion and protein identification by liquid chromatography−mass spectrometry (LC-MS). A total of 210 protein spots were detected, and 16 protein spots showed statistically significant differences (p < 0.05) in the expression levels between groups. Ten spots showed a higher intensity in the high-PACAP-concentration group, while six spots were more abundant in the low-PACAP-concentration group. The functions of the differentially expressed proteins indicate that the PACAP level of plasma is related to the lipid metabolism and immune status of cattle.
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3
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Cheng AA, Li W, Walker TM, Silvers C, Arendt LM, Hernandez LL. Investigating the complex interplay between genotype and high-fat-diet feeding in the lactating mammary gland using the Tph1 and Ldlr knockout models. Am J Physiol Endocrinol Metab 2021; 320:E438-E452. [PMID: 33427054 PMCID: PMC7988787 DOI: 10.1152/ajpendo.00456.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 12/12/2022]
Abstract
Obesity is a prevailing problem across the globe. Women who are obese have difficulty initiating and sustaining lactation. However, the impact of genetics and diet on breastfeeding outcomes is understudied. Here we explore the effect of diet and genotype on lactation. We utilized the low-density lipoprotein receptor (Ldlr-KO) transgenic mouse model as an obesity and hypercholesterolemia model. Additionally, we used the tryptophan hydroxylase 1 (Tph1-KO) mouse, recently identified as a potential anti-obesogenic model, to investigate if addition of Tph1-KO could ameliorate negative effects of obesity in Ldlr-KO mice. We created a novel transgenic mouse line by combining the Ldlr and Tph1 [double knockout (DKO)] mice to study the interaction between the two genotypes. Female mice were fed a low-fat diet (LFD; 10% fat) or high-fat diet (HFD; 60% fat) from 3 wk of age through early [lactation day 3 (L3)] or peak lactation [lactation day 11 (L11)]. After 4 wk of consuming either LFD or HFD, female mice were bred. On L2 and L10, dams were milked to investigate the effect of diet and genotype on milk composition. Dams were euthanized on L3 or L11. There was no impact of diet or genotype on milk protein or triglycerides (TGs) on L2; however, by L10, Ldlr-KO and DKO dams had increased TG levels in milk. RNA-sequencing of L11 mammary glands demonstrated Ldlr-KO dams fed HFD displayed enrichment of genes involved in immune system pathways. Interestingly, the DKO may alter vesicle budding and biogenesis during lactation. We also quantified macrophages by immunostaining for F4/80+ cells at L3 and L11. Diet played a significant role on L3 (P = 0.013), but genotype played a role at L11 (P < 0.0001) on numbers of F4/80+ cells. Thus the impact of diet and genotype on lactation differs depending on stage of lactation, illustrating complexities of understanding the intersection of these parameters.NEW & NOTEWORTHY We have created a novel mouse model that is focused on understanding the intersection of diet and genotype on mammary gland function during lactation.
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Affiliation(s)
- Adrienne A Cheng
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin
| | - Wenli Li
- US Department of Agriculture-Dairy Forage, Madison, Wisconsin
| | - Teresa M Walker
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin
| | - Caylee Silvers
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
| | - Lisa M Arendt
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
| | - Laura L Hernandez
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin
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4
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de Sousa Rebouças A, Costa Lemos da Silva AG, Freitas de Oliveira A, Thalia Pereira da Silva L, de Freitas Felgueiras V, Cruz MS, Silbiger VN, da Silva Ribeiro KD, Dimenstein R. Factors Associated with Increased Alpha-Tocopherol Content in Milk in Response to Maternal Supplementation with 800 IU of Vitamin E. Nutrients 2019; 11:nu11040900. [PMID: 31013594 PMCID: PMC6520676 DOI: 10.3390/nu11040900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 11/16/2022] Open
Abstract
Background: Vitamin E supplementation might represent an efficient strategy to increase the vitamin E content in milk. The present study aimed to evaluate the impact of supplementation with 800 IU RRR-alpha-tocopherol on the alpha-tocopherol content of milk and the factors associated with the increase in vitamin E. Methods: Randomized clinical trial with 79 lactating women from Brazil, who were assigned to the control group, or to the supplemented group (800 IU of RRR-alpha-tocopherol). Milk and serum were collected between 30 and 90 days after delivery (collection 1), and on the next day (collection 2). Alpha-tocopherol was analyzed using high-performance liquid chromatography. Results: In the supplemented group, the alpha-tocopherol content in serum and milk increased after supplementation (p < 0.001). In the multivariate analysis, only alpha-tocopherol in milk (collection 1) was associated with the level of this vitamin in milk after supplementation (β = 0.927, p < 0.001), and binary logistic regression showed that the dietary intake was the only determinant for the greater effect of supplementation in milk. Conclusion: The pre-existing vitamin level in milk and diet are determinants for the efficacy of supplementation in milk, suggesting that in populations with vitamin E deficiency, high-dose supplementation can be used to restore its level in milk.
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Affiliation(s)
- Amanda de Sousa Rebouças
- Department of Biochemistry, Federal University of Rio Grande do Norte, 59078-970 Natal-RN, Brazil.
| | | | | | | | | | - Marina Sampaio Cruz
- Department of Pharmacy, Federal University of Rio Grande do Norte, 59012-570 Natal-RN, Brazil.
| | | | | | - Roberto Dimenstein
- Department of Biochemistry, Federal University of Rio Grande do Norte, 59078-970 Natal-RN, Brazil.
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5
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Mather IH, Masedunskas A, Chen Y, Weigert R. Symposium review: Intravital imaging of the lactating mammary gland in live mice reveals novel aspects of milk-lipid secretion. J Dairy Sci 2019; 102:2760-2782. [PMID: 30471915 PMCID: PMC7094374 DOI: 10.3168/jds.2018-15459] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/21/2018] [Indexed: 12/22/2022]
Abstract
Milk fat comprises membrane-coated droplets of neutral lipid, which constitute the predominant source of lipids for survival of the suckling neonate. From the perspective of the dairy industry, they are the basis for the manufacture of butter and essential ingredients in the production of cheese, yogurt, and specialty dairy produce. To provide mechanistic insight into the assembly and secretion of lipid droplets during lactation, we developed novel intravital imaging techniques using transgenic mice, which express fluorescently tagged marker proteins. The number 4 mammary glands were surgically prepared under a deep plane of anesthesia and the exposed glands positioned as a skin flap with intact vascular supply on the stage of a laser-scanning confocal microscope. Lipid droplets were stained by prior exposure of the glands to hydrophobic fluorescent BODIPY (boron-dipyrromethene) dyes and their formation and secretion monitored by time-lapse subcellular microscopy over periods of 1 to 2 h. Droplets were transported to the cell apex by directed (superdiffusive) motion at relatively slow and intermittent rates (0-2 µm/min). Regardless of size, droplets grew by numerous fusion events during transport and as they were budding from the cell enveloped by apical membranes. Surprisingly, droplet secretion was not constitutive but required an injection of oxytocin to induce contraction of the myoepithelium with subsequent release of droplets into luminal spaces. These novel results are discussed in the context of the current paradigm for milk fat synthesis and secretion and as a template for future innovations in the dairy industry.
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Affiliation(s)
- Ian H Mather
- Department of Animal and Avian Sciences, University of Maryland, College Park 20742; National Cancer Institute and National Institute of Craniofacial and Dental Research, National Institutes of Health, Bethesda, MD 20892.
| | - Andrius Masedunskas
- National Cancer Institute and National Institute of Craniofacial and Dental Research, National Institutes of Health, Bethesda, MD 20892
| | - Yun Chen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21205
| | - Roberto Weigert
- National Cancer Institute and National Institute of Craniofacial and Dental Research, National Institutes of Health, Bethesda, MD 20892
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6
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Plat J, Baumgartner S, Vanmierlo T, Lütjohann D, Calkins KL, Burrin DG, Guthrie G, Thijs C, Te Velde AA, Vreugdenhil ACE, Sverdlov R, Garssen J, Wouters K, Trautwein EA, Wolfs TG, van Gorp C, Mulder MT, Riksen NP, Groen AK, Mensink RP. Plant-based sterols and stanols in health & disease: "Consequences of human development in a plant-based environment?". Prog Lipid Res 2019; 74:87-102. [PMID: 30822462 DOI: 10.1016/j.plipres.2019.02.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 02/13/2019] [Accepted: 02/25/2019] [Indexed: 01/27/2023]
Abstract
Dietary plant sterols and stanols as present in our diet and in functional foods are well-known for their inhibitory effects on intestinal cholesterol absorption, which translates into lower low-density lipoprotein cholesterol concentrations. However, emerging evidence suggests that plant sterols and stanols have numerous additional health effects, which are largely unnoticed in the current scientific literature. Therefore, in this review we pose the intriguing question "What would have occurred if plant sterols and stanols had been discovered and embraced by disciplines such as immunology, hepatology, pulmonology or gastroenterology before being positioned as cholesterol-lowering molecules?" What would then have been the main benefits and fields of application of plant sterols and stanols today? We here discuss potential effects ranging from its presence and function intrauterine and in breast milk towards a potential role in the development of non-alcoholic steatohepatitis (NASH), cardiovascular disease (CVD), inflammatory bowel diseases (IBD) and allergic asthma. Interestingly, effects clearly depend on the route of entrance as observed in intestinal-failure associated liver disease (IFALD) during parenteral nutrition regimens. It is only until recently that effects beyond lowering of cholesterol concentrations are being explored systematically. Thus, there is a clear need to understand the full health effects of plant sterols and stanols.
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Affiliation(s)
- J Plat
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands.
| | - S Baumgartner
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands
| | - T Vanmierlo
- Department of Immunology and Biochemistry, Biomedical Research Institute (Biomed) Hasselt University, Hasselt, Belgium; Division of Translational Neuroscience, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, the Netherlands
| | - D Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - K L Calkins
- David Geffen School of Medicine, University of California Los Angeles, Mattel Children's Hospital at UCLA, Los Angeles, CA; Department of Pediatrics, Division of Neonatology and Developmental Biology, Neonatal Research Center, USA
| | - D G Burrin
- Department of Pediatrics, USDA Children's Nutrition Research Center, Baylor College of Medicine, Houston, USA
| | - G Guthrie
- Department of Pediatrics, USDA Children's Nutrition Research Center, Baylor College of Medicine, Houston, USA
| | - C Thijs
- Department of Epidemiology, Care and Public Health Research Institute (CAPHRI), Maastricht University, Maastricht, the Netherlands
| | - A A Te Velde
- Tytgat Institute for Liver and Intestinal Research, Amsterdam Medical Center, the Netherlands
| | - A C E Vreugdenhil
- Department of Pediatrics, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands
| | - R Sverdlov
- Department of Molecular Genetics, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands
| | - J Garssen
- Utrecht University, Division Pharmacology, Utrecht Institute for Pharmaceutical Sciences, the Netherlands
| | - K Wouters
- Department of Internal Medicine, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| | | | - T G Wolfs
- Department of Pediatrics, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands
| | - C van Gorp
- Department of Pediatrics, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands
| | - M T Mulder
- Department of Internal Medicine, Rotterdam University, Rotterdam, the Netherlands
| | - N P Riksen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - A K Groen
- Amsterdam Diabetes Center and Department of Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | - R P Mensink
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands
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7
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Dimova LG, Lohuis MAM, Bloks VW, Tietge UJF, Verkade HJ. Milk cholesterol concentration in mice is not affected by high cholesterol diet- or genetically-induced hypercholesterolaemia. Sci Rep 2018; 8:8824. [PMID: 29891894 PMCID: PMC5995842 DOI: 10.1038/s41598-018-27115-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/15/2018] [Indexed: 12/02/2022] Open
Abstract
Breast milk cholesterol content may imply to affect short- and long-term cholesterol homeostasis in the offspring. However, mechanisms of regulating milk cholesterol concentration are only partly understood. We used different mouse models to assess the impact of high cholesterol diet (HC)- or genetically-induced hypercholesterolaemia on milk cholesterol content. At day 14 postpartum we determined milk, plasma and tissue lipids in wild type (WT), LDL receptor knockout (Ldlr−/−), and ATP-binding cassette transporter G8 knockout (Abcg8−/−) mice fed either low- or 0.5% HC diet. In chow-fed mice, plasma cholesterol was higher in Ldlr−/− dams compared to WT. HC-feeding increased plasma cholesterol in all three models compared to chow diet. Despite the up to 5-fold change in plasma cholesterol concentration, the genetic and dietary conditions did not affect milk cholesterol levels. To detect possible compensatory changes, we quantified de novo cholesterol synthesis in mammary gland and liver, which was strongly reduced in the various hypercholesterolaemic conditions. Together, these data suggest that milk cholesterol concentration in mice is not affected by conditions of maternal hypercholesterolaemia and is maintained at stable levels via ABCG8- and LDLR-independent mechanisms. The robustness of milk cholesterol levels might indicate an important physiological function of cholesterol supply to the offspring.
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Affiliation(s)
- Lidiya G Dimova
- Department of Pediatrics, Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Mirjam A M Lohuis
- Department of Pediatrics, Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Vincent W Bloks
- Department of Pediatrics, Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Uwe J F Tietge
- Department of Pediatrics, Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Henkjan J Verkade
- Department of Pediatrics, Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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8
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Transcellular route as the most probable explanation for the presence of plasminogen in mammal׳s milk. J Theor Biol 2016; 395:221-226. [DOI: 10.1016/j.jtbi.2016.01.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 12/06/2015] [Accepted: 01/15/2016] [Indexed: 01/24/2023]
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9
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McManaman JL. Lipid transport in the lactating mammary gland. J Mammary Gland Biol Neoplasia 2014; 19:35-42. [PMID: 24567110 PMCID: PMC4413448 DOI: 10.1007/s10911-014-9318-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/04/2014] [Indexed: 12/11/2022] Open
Abstract
Mammalian cells depend on phospholipid (PL) and fatty acid (FA) transport to maintain membrane structure and organization, and to fuel and regulate cellular functions. In mammary glands of lactating animals, copious milk secretion, including large quantities of lipid in some species, requires adaptation and integration of PL and FA synthesis and transport processes to meet secretion demands. At present few details exist about how these processes are regulated within the mammary gland. However, recent advances in our understanding of the structural and molecular biology of membrane systems and cellular lipid trafficking provide insights into the mechanisms underlying the regulation and integration of PL and FA transport processes the lactating mammary gland. This review discusses the PL and FA transport processes required to maintain the structural integrity and organization of the mammary gland and support its secretory functions within the context of current molecular and cellular models of their regulation.
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Affiliation(s)
- James L McManaman
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Mail Stop 8613, 12700 E. 19th Ave., Aurora, CO, 80045, USA,
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10
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Ontsouka EC, Albrecht C. Cholesterol transport and regulation in the mammary gland. J Mammary Gland Biol Neoplasia 2014; 19:43-58. [PMID: 24510467 DOI: 10.1007/s10911-014-9316-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 01/22/2014] [Indexed: 01/28/2023] Open
Abstract
The milk-producing alveolar epithelial cells secrete milk that remains after birth the principal source of nutrients for neonates. Milk secretion and composition are highly regulated processes via integrated actions of hormones and local factors which involve specific receptors and downstream signal transduction pathways. Overall milk composition is similar among mammalian species, although the content of individual constituents such as lipids may significantly differ from one species to another. The milk lipid fraction is essentially composed of triglycerides, which represent more than 95 % of the total lipids in human and commercialized bovine milk. Though sterols, including cholesterol, which is the major milk sterol, represent less than 0.5 % of the total milk lipid fraction, they are of key importance for several biological processes. Cholesterol is required for the formation of biological membranes especially in rapidly growing organisms, and for the synthesis of sterol-based compounds. Cholesterol found in milk originates predominantly from blood uptake and, to a certain extent, from local synthesis in the mammary tissue. The present review summarizes current knowledge on cellular mechanisms and regulatory processes determining intra- and transcellular cholesterol transport in the mammary gland. Cholesterol exchanges between the blood, the mammary alveolar cells and the milk, and the likely role of active cholesterol transporters in these processes are discussed. In this context, the hormonal regulation and signal transduction pathways promoting active cholesterol transport as well as potential regulatory crosstalks are highlighted.
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Affiliation(s)
- Edgar C Ontsouka
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland
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11
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Abstract
Lactation physiology is a process that is only partly understood. Proteomics techniques have shown to be useful to help advance the knowledge on lactation physiology in human and rodent species but have not been used as major tools for dairy cows, except for mastitis. In this paper, advanced non-targeted proteomics techniques (Filter aided sample preparation and NanoLC-Orbitrap-MS/MS) were applied to study the milk fat globule membrane and milk serum fraction, resulting in the identification of 246 proteins. Of these, 23 transporters and enzymes were related to lipid synthesis and secretion in mammary gland and their functions are discussed in detail. The identification of these intracellular transporters and enzymes in milk provides a possibility of using milk itself to study lipid synthesis and secretion pathways. This full-scale scan of milk proteins by using non-targeted proteomic analysis helps to reveal the important proteins involved in lipid synthesis and secretion for further examination in targeted studies.
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12
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Mani O, Körner M, Sorensen MT, Sejrsen K, Wotzkow C, Ontsouka CE, Friis RR, Bruckmaier RM, Albrecht C. Expression, localization, and functional model of cholesterol transporters in lactating and nonlactating mammary tissues of murine, bovine, and human origin. Am J Physiol Regul Integr Comp Physiol 2010; 299:R642-54. [DOI: 10.1152/ajpregu.00723.2009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Members of the ATP-binding cassette (ABC) transporters play a pivotal role in cellular lipid efflux. To identify candidate cholesterol transporters implicated in lipid homeostasis and mammary gland (MG) physiology, we compared expression and localization of ABCA1, ABCG1, and ABCA7 and their regulatory genes in mammary tissues of different species during the pregnancy-lactation cycle. Murine and bovine mammary glands (MGs) were investigated during different functional stages. The abundance of mRNAs was determined by quantitative RT-PCR. Furthermore, transporter proteins were localized in murine, bovine, and human MGs by immunohistochemistry. In the murine MG, ABCA1 mRNA abundance was elevated during nonlactating compared with lactating stages, whereas ABCA7 and ABCA1 mRNA profiles were not altered. In the bovine MG, ABCA1, ABCG1, and ABCA7 mRNAs abundances were increased during nonlactating stages compared with lactation. Furthermore, associations between mRNA levels of transporters and their regulatory genes LXRα, PPARγ, and SREBPs were found. ABCA1, ABCG1, and ABCA7 proteins were localized in glandular MG epithelial cells (MEC) during lactation, whereas during nonlactating stages, depending on species, the proteins showed distinct localization patterns in MEC and adipocytes. Our results demonstrate that ABCA1, ABCG1, and ABCA7 are differentially expressed between lactation and nonlactating stages and in association with regulatory genes. Combined expression and localization data suggest that the selected cholesterol transporters are universal MG transporters involved in transport and storage of cholesterol and in lipid homeostasis of MEC. Because of the species-specific expression patterns of transporters in mammary tissue, mechanisms of cholesterol homeostasis seem to be differentially regulated between species.
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Affiliation(s)
- Orlando Mani
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Meike Körner
- Institute of Pathology, University of Bern, Switzerland
| | - Martin T. Sorensen
- Department of Animal Health, Welfare and Nutrition, Aarhus University, Tjele, Denmark
| | - Kristen Sejrsen
- Department of Animal Health, Welfare and Nutrition, Aarhus University, Tjele, Denmark
| | - Carlos Wotzkow
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Corneille E. Ontsouka
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Robert R. Friis
- Department of Clinical Research, University of Bern, Bern, Switzerland; and
| | | | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
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13
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Mani O, Sorensen M, Sejrsen K, Bruckmaier R, Albrecht C. Differential expression and localization of lipid transporters in the bovine mammary gland during the pregnancy-lactation cycle. J Dairy Sci 2009; 92:3744-56. [DOI: 10.3168/jds.2009-2063] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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14
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Viturro E, Koenning M, Kroemer A, Schlamberger G, Wiedemann S, Kaske M, Meyer HHD. Cholesterol synthesis in the lactating cow: Induced expression of candidate genes. J Steroid Biochem Mol Biol 2009; 115:62-7. [PMID: 19429461 DOI: 10.1016/j.jsbmb.2009.02.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 02/18/2009] [Indexed: 11/21/2022]
Abstract
Despite the extensive knowledge for other species, cholesterol metabolism in ruminants is nowadays still not clear. Huge differences in milk cholesterol concentration are observed between breeds, managing strategies, individuals and moment of the lactating cycle, but the genetic actors working in the process of cholesterol secretion into milk have not been identified. As ruminant diet contains no cholesterol, understanding the mechanisms and regulation of synthesis, transport and secretion into milk is crucial when trying to reduce the amount of this metabolite in dairy products. The present work aims to study the expression of candidate genes for these processes in the liver of Bos taurus during the lactating cycle. Liver biopsies were obtained from 16 adult brown Swiss cows at different time points (2 weeks pre-partum and 0, 2, 4 and 8 weeks post-partum). After RNA extraction and reverse transcription, gene expression of candidate genes was studied using quantitative RT-PCR. Key enzymes of the cholesterol synthesis (3-hydroxy-methyglutaryl-coenzyme-A (HMG-CoA) synthase, HMG-CoA reductase and farnesyldiphosphat-farnesyltransferase (FDFT)) and gene expression feed-back regulators involved in lipid metabolism (sterol regulatory element binding proteins (SREBP1and 2) SREBP-cleavage activating protein (Scap) were selected as candidate genes. HMG-CoA-reductase and FDFT showed a huge expression increase until week 2 post-partum (p<0.01), most probably in response to the new requirements in the mammary gland. As well, and as a possible explanation for such modifications, an increase in the expression of the regulators SREBP1 and Scap was observed (p<0.01 and p<0.05 respectively). Most important, the whole synthesis machinery showed a coordinated regulation, as highly significant positive correlations were found between the expression levels of the above mentioned enzymes (p<0.01). The increase of milk and blood cholesterol levels in B. taurus after parturition might be the result of a coordinated induction in the expression of key liver enzymes and their regulating factors.
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Affiliation(s)
- Enrique Viturro
- Physiology Weihenstephan, Technische Universitaet Muenchen, Weihenstephaner Berg, Freising, Germany.
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Abstract
Abstract Vitamin D has emerged from obscurity, and its effects on various organ systems throughout the body down to the cellular level are being discovered. What was once thought to be a simple hormone affecting only bone and calcium metabolism has shifted. We no longer see vitamin D as a "vitamin" important only in childhood, but as a complex hormone that is involved not only in calcium homeostasis but also in the integrity of the innate immune system. Vitamin D deficiency is linked to inflammatory and long-latency diseases such as multiple sclerosis, rheumatoid arthritis, tuberculosis, diabetes, and various cancers, to name a few. In this review, we trace how we came to view vitamin D and how that view led to one of the largest epidemics of nutrient deficiency beginning in the late 20(th) century. We then discuss the needs of vitamin D in the context of the breastfeeding mother and her infant and child, why breastfed infants are particularly at risk, and what to do about it.
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Affiliation(s)
- Carol L Wagner
- Department of Pediatrics, Pediatric Nutritional Research Center, Darby Children's Research Institute, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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16
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Abstract
Vitamin E is a fat-soluble nutrient that is extremely important during the early stages of life, from the time of conception to the postnatal development of the infant. The mechanisms involved in its placental and mammary uptake appear to be allowed by the presence of lipoprotein receptors (LDL-receptor, VLDL-receptor, scavenger receptor class B type I) together with lipoprotein lipase at the placental and mammary barriers. In addition, alpha-tocopherol transfer protein has been described as playing an essential role in the selective transfer of RRR-alpha-tocopherol across the placenta. Lower alpha-tocopherol concentrations are found in cord blood as compared to maternal circulation. The ingestion of colostrum which contains very high levels of vitamin E is therefore of utmost importance to supply the newborn with an essential defense against oxygen toxicity. Pregnancy is sometimes associated with complications that may lead to a premature delivery of the baby. Preterm infants are usually facing an oxidative stress that is among others related to a deficiency in alpha-tocopherol, as it accumulates mainly during the third trimester of pregnancy. Despite vitamin E supplementation, preterm infants usually require significantly longer to replenish their serum alpha-tocopherol levels than full-term infants. The use of vitamin E as a therapeutic agent in preeclampsia, which induces high maternal and fetal morbidity and mortality, has been discussed in numerous papers. This disorder is indeed associated with an important oxidative stress in the placenta and maternal circulation. However, the most recent studies did not show a beneficial effect of vitamin E administration in this pathology.
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Affiliation(s)
- Cathy Debier
- Institut des Sciences de la Vie, Unité de Biochimie de la Nutrition, Université Catholique de Louvain, Croix du Sud 2/8, B-1348 Louvain-la-Neuve, Belgium
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Lietz G, Mulokozi G, Henry JCK, Tomkins AM. Xanthophyll and hydrocarbon carotenoid patterns differ in plasma and breast milk of women supplemented with red palm oil during pregnancy and lactation. J Nutr 2006; 136:1821-7. [PMID: 16772443 DOI: 10.1093/jn/136.7.1821] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Currently limited information exists on how maternal supplementation with provitamin A carotenoids might influence the carotenoid pattern in breast milk during lactation. This study was designed to investigate the effect of maternal red palm oil supplementation ( approximately 12 g/d) throughout the 3rd trimester of pregnancy and the first 3 mo postpartum on carotenoid pattern in both plasma and breast milk. Plasma and breast milk alpha- and beta-carotene concentrations increased in response to red palm oil supplementation and were different (P < 0.001) from the control group at both 1 and 3 mo postpartum. Plasma lutein and zeaxanthin concentrations were reduced (P < 0.001) from pregnancy to 1 mo postpartum and remained stable until 3 mo postpartum. However, breast milk lutein concentrations, expressed per gram of milk fat, increased (P < 0.05) in both groups from 1 to 3 mo postpartum. The results of this study show that there are proportionally more hydrocarbon carotenoids such as alpha- and beta-carotene in plasma than in breast milk, whereas xanthophylls, such as lutein and zeaxanthin, are proportionally more prevalent in breast milk. More importantly, red palm oil supplementation increases the milk concentrations of provitamin A carotenes without decreasing the milk concentrations of xanthophylls. In summary, this study demonstrates that a regulated uptake of polar carotenoids into breast milk exists and that supplementation with alpha- and beta-carotene does not negatively affect this transfer. The mechanisms behind this transport are not fully understood and merit further study.
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Affiliation(s)
- Georg Lietz
- Centre for International Child Health (CICH), Institute of Child Health, London WC1N 1EH, UK.
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18
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Nieland TJF, Ehrlich M, Krieger M, Kirchhausen T. Endocytosis is not required for the selective lipid uptake mediated by murine SR-BI. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1734:44-51. [PMID: 15866482 DOI: 10.1016/j.bbalip.2005.02.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Revised: 02/01/2005] [Accepted: 02/03/2005] [Indexed: 10/25/2022]
Abstract
The scavenger receptor class B, type I (SR-BI) mediates the cellular selective uptake of cholesteryl esters and other lipids from high-density lipoproteins (HDL) and low-density lipoproteins (LDL). This process, unlike classical receptor-mediated endocytosis, does not result in lipoprotein degradation. Instead, the lipid depleted particles are released into the medium. Here we show that selective lipid uptake mediated by murine SR-BI can be uncoupled from the endocytosis of HDL or LDL particles. We found that blocking selective lipid uptake by incubating cells with the small chemical inhibitors BLT-1 or BLT-4 did not affect endocytosis of HDL. Similarly, blocking endocytosis by hyperosmotic sucrose or K+ depletion did not prevent selective lipid uptake from HDL or LDL. These findings suggest that mSR-BI-mediated selective uptake occurs at the cell surface upon the association of lipoproteins with mSR-BI and does not require endocytosis of HDL or LDL particles.
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Affiliation(s)
- Thomas J F Nieland
- Department of Cell Biology, Harvard Medical School and The CBR Institute for Biomedical Research, 200 Longwood Avenue, Room 134, Boston, MA 02115, USA
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Monks J, Neville MC. Albumin transcytosis across the epithelium of the lactating mouse mammary gland. J Physiol 2004; 560:267-80. [PMID: 15297572 PMCID: PMC1665199 DOI: 10.1113/jphysiol.2004.068403] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2004] [Accepted: 07/29/2004] [Indexed: 12/20/2022] Open
Abstract
Murine milk contains 18 mg ml(-1) serum albumin, a concentration equal to that in the serum of the lactating mouse. We examined cellular transport using in vivo methods in the mouse. At steady state the specific activity of (125)I-albumin injected into the blood stream was equal in plasma and whey, confirming that milk albumin is extra-mammary in origin. Fluorescent albumin crossed the gland from basolateral surface to lumen via cytoplasmic vesicles, but was not transported in the apical to basal direction. Albumin was segregated from transferrin at the basal surface of the epithelial cells and did not colocalize with either caveolin-1 or -2. Vesicular transport was not disrupted by filipin providing additional evidence that, unlike the vascular endothelium, caveoli are not involved. Cytoplasmic albumin was localized to vesicles containing IgA and transport was disrupted by agents that interfere with clathrin-mediated endocytosis. Together, these findings provide evidence that albumin is transported across the mammary epithelium by the same pathway as immunoglobulin. The possibility that the massive transfer of albumin into mouse milk is mediated by fluid phase transport is considered.
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Affiliation(s)
- Jenifer Monks
- Department of Physiology and Biophysics, Room 2802-2, Box C240, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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20
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Rigotti A, Miettinen HE, Krieger M. The role of the high-density lipoprotein receptor SR-BI in the lipid metabolism of endocrine and other tissues. Endocr Rev 2003; 24:357-87. [PMID: 12788804 DOI: 10.1210/er.2001-0037] [Citation(s) in RCA: 313] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Because cholesterol is a precursor for the synthesis of steroid hormones, steroidogenic tissues have evolved multiple pathways to ensure adequate supplies of cholesterol. These include synthesis, storage as cholesteryl esters, and import from lipoproteins. In addition to endocytosis via members of the low-density lipoprotein receptor superfamily, steroidogenic cells acquire cholesterol from lipoproteins by selective lipid uptake. This pathway, which does not involve lysosomal degradation of the lipoprotein, is mediated by the scavenger receptor class B type I (SR-BI). SR-BI is highly expressed in steroidogenic cells, where its expression is regulated by various trophic hormones, as well as in the liver. Studies of genetically manipulated strains of mice have established that SR-BI plays a key role in regulating lipoprotein metabolism and cholesterol transport to steroidogenic tissues and to the liver for biliary secretion. In addition, analysis of SR-BI-deficient mice has shown that SR-BI expression is important for alpha-tocopherol and nitric oxide metabolism, as well as normal red blood cell maturation and female fertility. These mouse models have also revealed that SR-BI can protect against atherosclerosis. If SR-BI plays similar physiological and pathophysiological roles in humans, it may be an attractive target for therapeutic intervention in cardiovascular and reproductive diseases.
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Affiliation(s)
- Attilio Rigotti
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica, Santiago, Chile
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21
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Abstract
The presence of drugs or other potentially toxic materials in milk is an obvious public health risk, especially to infants and neonates. There is also increasing concern that human breast cancer is principally epigenetic in origin and results from environmentally produced lesions. Little is known about the mechanisms by which toxic substances enter milk or mammary tissue but knowledge of these processes is important to toxicologists and researchers involved in drug design and metabolism. Five general pathways have been described for transport of proteins, lipids, ions, nutrients and water into milk. Four of these pathways are transcellular, involving transport across at least two membrane barriers; the fifth is paracellular and allows direct exchange of interstitial and milk components. Solute transport by these pathways is mediated by a diverse, and complex array of transport and secretory processes that are regulated by hormonal, developmental, and physiological factors. Current research is beginning to define the mechanisms underlying some of these processes, however the regulation and coordination of solute transport mechanisms remains poorly understood. In this article we review our current understanding of the normal solute transport and secretory processes involved in milk production, and discuss potential regulatory mechanisms.
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Affiliation(s)
- James L McManaman
- Department of Physiology, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
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Katoh N. Relevance of apolipoproteins in the development of fatty liver and fatty liver-related peripartum diseases in dairy cows. J Vet Med Sci 2002; 64:293-307. [PMID: 12014573 DOI: 10.1292/jvms.64.293] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Most metabolic diseases in dairy cows occur during the peripartum period and are suggested to be derived from fatty liver initially developed during the nonlactating stage. Fatty liver is induced by hepatic uptake of nonesterified fatty acids that are released in excess by adipose tissues attributable to negative energy balance. The fatty accumulation leads to impairment of lipoprotein metabolism in the liver, and the impairment in turn influences other metabolic pathways in extrahepatic tissues such as the steroid hormone production by the corpus luteum. Detailed understanding of the impaired lipoprotein metabolism is crucial for elucidation of the mechanistic bases of the development of fatty liver and fatty liver-related peripartum diseases. This review summarizes results on evaluation of lipoprotein lipid and protein concentrations and enzyme activity in cows with fatty liver and those with ketosis, left displacement of the abomasum, milk fever, downer syndrome and retained placenta. Obtained data strongly suggest that decreases in serum concentrations of apolipoprotein B-100, apolipoprotein A-I and apolipoprotein C-III, a reduction in activity of lecithin:cholesterol acyltransferase and induction of haptoglobin and serum amyloid A are intimately related to the development of fatty liver and fatty liver-related diseases. Moreover, determination of the apolipoprotein concentrations and enzyme activity during the peripartum period is useful for early diagnoses of these diseases.
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Affiliation(s)
- Norio Katoh
- Hokkaido Research Station, National Institute of Animal Health, Sapporo, Japan
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