1.
Delay of stroke onset by milk proteins in stroke-prone spontaneously hypertensive rats.
Source
Department of Nutritional Science, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8636, Japan. ezaki@nih.go.jp.
Abstract
BACKGROUND AND PURPOSE:
There is an inverse association between dairy food consumption and the incidence of stroke in observational studies. However, it is unknown whether the relationship is causal or, if so, what components in milk are responsible for reducing the incidence of stroke.
METHODS:
Stroke-prone spontaneously hypertensive rats were fed diets comprising amino acids, proteins from different sources (casein, whey, soybean, or egg white), or fats from different sources (butter, beef tallow, or cocoa butter) and the onset of stroke and lifespan were examined.
RESULTS:
Increasing the amount of dietary casein (5% to 55% of caloric intake) markedly delayed the onset of stroke. However, when stroke-prone spontaneously hypertensive rats were fed diets containing 55% of caloric intake as protein, rats fed casein or whey protein, a major component of milk, displayed a delayed onset of stroke compared with rats fed soybean or egg white protein. Rats fed an amino acids diet containing the same amino acids composition as casein did not have a delay in the onset of stroke. Increasing dietary fats, including butter as well as beef tallow and cocoa butter, did not affect the onset of stroke. All diets did not affect blood pressure in the early stage.
CONCLUSIONS:
These data suggest that the inverse association between dairy food consumption and incidence of stroke in epidemiological studies is causal and that peptides in milk protein, but not fat, might be responsible for this effect.
Acute effect of whey peptides upon blood pressure of hypertensive rats, and relationship with their angiotensin-converting enzyme inhibitory activity.
Source
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
Abstract
Scope: The aim of this study was to investigate the antihypertensive effect of a peptide fraction (PepC) obtained from a whey protein concentrate following hydrolysis by Cynara cardunculus, as well as of its fraction with MW below 3 kDa (PepCF). Both these concentrates encompassed peptides that exhibited potent in vitro inhibition of angiotensin-converting enzyme (ACE): two were released from α-lactalbumin - KGYGGVSLPEW and DKVGINYW, and one from β-lactoglobulin - DAQSAPLRVY. Methods and results: Upon oral administration, by gastric intubation, of 400 mg/kg body weight (bw) of those peptide concentrates, or 5 mg/kg bw of the corresponding synthetic peptides, to 12 wk-old spontaneously hypertensive rats (SHR), the systolic and diastolic blood pressures were monitored by the tail-cuff method - before, and 2, 4, 6, 8 and 24 h afterwards. Water and zofenopril (5 mg/kg bw) - a known ACE-inhibitor, were used as negative and positive controls, respectively. Acute administration of PepC, PepCF, KGYGGVSLPEW, DKVGINYW and DAQSAPLRVY caused antihypertensive effects in SHR; the maximum effect occurred by 4 h and 6 h after administration of the peptide concentrates and the synthetic peptides, respectively. PepC and KGYGGVSLPEW also showed ACE-inhibitory activity in vivo: the pressor effect of angiotensin I was significantly lower, and the response to bradykinin increased when the rats were pre-treated with either product. Conclusion: Our results strongly suggest that PepC will be effective as nutraceutical ingredient for the formulation of functional foods aimed at hypertension control.
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Hydrolysis of whey protein isolate using subcritical water.
Source
Authors are with Dept. of Food Science, Univ. of Arkansas, 2650 North Young Ave., Fayetteville, AR 72704, U.S.A. Direct inquiries to author Morawicki (E-mail: rmorawic@uark.edu).
Abstract
Hydrolyzed whey protein isolate (WPI) is used in the food industry for protein enrichment and modification of functional properties. The purpose of the study was to determine the feasibility of subcritical water hydrolysis (SWH) on WPI and to determine the temperature and reaction time effects on the degree of hydrolysis (DH) and the production of peptides and free amino acids (AAs). Effects of temperature (150 to 320 °C) and time (0 to 20 min) were initially studied with a central composite rotatable design followed by a completely randomized factorial design with temperature (250 and 300 °C) and time (0 to 50 min) as factors. SWH was conducted in an electrically heated, 100-mL batch, high pressure vessel. The DH was determined by a spectrophotometric method after derivatization. The peptide molecular weights (MWs) were analyzed by gel electrophoresis and mass spectrometry, and AAs were quantified by high-performance liquid chromotography. An interaction of temperature and time significantly affected the DH and AA concentration. As the DH increased, the accumulation of lower MWpeptides also increased following SWH (and above 10% DH, the majority of peptides were <1000 Da). Hydrolysis at 300 °C for 40 min generated the highest total AA concentration, especially of lysine (8.894 mg/g WPI). Therefore, WPI was successfully hydrolyzed by subcritical water, and with adjustment of treatment parameters there is reasonable control of the end-products.
© 2011 Institute of Food Technologists®
A newly designed enteral formula containing whey peptides and fermented milk product protects mice against concanavalin A-induced hepatitis by suppressing overproduction of inflammatory cytokines.
Source
Nutrition Research Dept., Food Science Research Labs, Meiji Co. Ltd., 540 Naruda, Odawara, Kanagawa 250-0862, Japan.
Abstract
BACKGROUND & AIMS:
We previously reported that whey protein derived from cow milk suppressed inflammation in a variety of animal models. We developed a newly designed enteral formula using peptidesprepared from whey protein and fermented milk product and investigated its ability to suppress inflammation in concanavalin A-induced hepatitis in mice.
METHODS:
C57BL/6 mice were fed a standard formula, AIN-93M, or enteral formula for 14 days, and then were intravenously administered concanavalin A. Inflammatory cytokines in plasma, liver, and spleen and markers of hepatic function in plasma were assessed at various time points. Livers were assessed for necrosis and apoptosis.
RESULTS:
After concanavalin A treatment, plasma aspartate aminotransaminase, alanine aminotransferase, TNF-α, IL-6, and IFN-γ levels were significantly lower in mice fed enteral formula than in those fed standard formula or AIN-93M. Liver TNF-α and IFN-γ, and spleen IL-6 and IFN-γ levels were lower in enteral formula-fed mice than in standard formula-fed mice 2 h after concanavalin A treatment. Necrosis and apoptosis were suppressed in the livers of enteral formula-fed mice.
CONCLUSIONS:
The new enteral formula is a potent novel immune-modulating diet that prevents aggravation of local inflammation by modulating systemic cytokine levels.
Copyright © 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
The impact of photo-induced molecular changes of dairy proteins on their ACE-inhibitory peptides and activity.
Source
NutriFOODchem unit (partner in Food2Know), Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
Abstract
Among all dietary proteins, dairy proteins are the most important source of bio-active peptides which can, however, be affected by modifications upon processing and storage. Since it is still unknown to which extent the biological activity of dairy proteins is altered by chemical reactions, this study focuses on the effect of photo-induced molecular changes on the angiotensin I converting enzyme (ACE) inhibitory activity. Milk proteins were dissolved in phosphate buffer containing riboflavin and stored under light at 4°C for one month during which the molecular changes and the ACE-inhibitory activity were analysed. An increase in the total protein carbonyls and the N-formylkynurenine content was observed, besides a decrease in the free thiol, tryptophan, tyrosine and histidine content. These changes were more severe in caseins compared with whey proteins and resulted moreover in the aggregation of caseins. Due to these photo-induced molecular changes, a significant loss of the ACE-inhibitory activity was observed for casein peptides. A peptide analysis moreover illustrated that the decreased activity was not attributed to a reduced digestibility but to losses of specific ACE-inhibitory peptides. The observed molecular changes, more specifically the degradation of specific amino acids and the casein aggregation, could be assigned as the cause of the altered peptide pattern and as such of the loss in ACE-inhibitory activity.
[Hydrolysis method for whey protein and the hypoglycemic activity of itspeptides in diabetic KKAy mice].
Source
Department of Nutrition, General Hospital of Chinese PLA, Beijing 100853, China. aqing_930@163.com
Abstract
OBJECTIVE:
To explore the hydrolysis method for whey protein with alkaline proteinase, and to investigate the hypoglycemic activity of the peptides in diabetic KKAy mice.
METHODS:
Whey protein was hydrolyzed with alkaline proteinase, and the degree of hydrolysis, nitrogen and amino acid content, mass spectrographic analysis of the peptides were determined. Changes of fasting blood glucose, random blood glucose, glucose tolerance and insulin levels in diabetic KKAy mice were measured after the peptides were given by gavage.
RESULTS:
The degree of hydrolysis of whey protein was 14.8%, the nitrogen in the peptides was 68.2%, and the molecular weight of the peptides was 900 - 1900 Dal, mostly was 1800 - 1900 Dal. Blood glucose of KKAy mice was decreased at 0.5 and 1 h after oral injection of the peptides, and insulin level was increased at 0.5 h after ingestion of the peptides.
CONCLUSION:
Fasting blood glucose and random blood glucose levels of type 2 diabetic KKAy mice could be significantly decreased, and the glucose tolerance and insulin secretion of mice could be improved by wheyprotein peptides.
- PMID:
- 22043716
- [PubMed - in process]
Differential effects of dietary protein sources on postprandial low-grade inflammation after a single high fat meal in obese non-diabetic subjects.
Source
Department of Endocrinology and Metabolism MEA, Aarhus University Hospital, Aarhus, Denmark. holmer-jensen@ki.au.dk
Abstract
BACKGROUND:
Obesity is a state of chronic low-grade inflammation. Chronic low-grade inflammation is associated with the pathophysiology of both type-2 diabetes and atherosclerosis. Prevention or reduction of chronic low-grade inflammation may be advantageous in relation to obesity related co-morbidity. In this study we investigated the acute effect of dietary protein sources on postprandial low-grade inflammatory markers after a high-fat meal in obese non-diabetic subjects.
METHODS:
We conducted a randomized, acute clinical intervention study in a crossover design. We supplemented a fat rich mixed meal with one of four dietary proteins - cod protein, whey isolate, gluten or casein. 11 obese non-diabetic subjects (age: 40-68, BMI: 30.3-42.0 kg/m2) participated and blood samples were drawn in the 4 h postprandial period. Adiponectin was estimated by ELISA methods and cytokines were analyzed by multiplex assay.
RESULTS:
MCP-1 and CCL5/RANTES displayed significant postprandial dynamics. CCL5/RANTES initially increased after all meals, but overall CCL5/RANTES incremental area under the curve (iAUC) was significantly lower after the whey meal compared with the cod and casein meals (P = 0.0053). MCP-1 was initially suppressed after all protein meals. However, the iAUC was significantly higher after whey meal compared to the cod and gluten meals (P = 0.04).
CONCLUSION:
We have demonstrated acute differential effects on postprandial low grade inflammation of four dietary proteins in obese non-diabetic subjects. CCL5/RANTES initially increased after all meals but the smallest overall postprandial increase was observed after the whey meal. MCP-1 was initially suppressed after all 4 protein meals and the whey meal caused the smallest overall postprandial suppression.
TRIAL REGISTRATION:
ClinicalTrials.gov ID: NCT00863564.
Therapeutic potential of human elafin.
Source
Proteo Biotech AG, Am-Kiel-Kanal 44, 24106 Kiel, Germany.
Abstract
Elafin is an endogenous human protein composed of an N-terminal transglutaminase substrate motif and a C-terminal WAP (whey acidic protein)-domain with antiproteolytic properties. Elafin is expressed predominantly in epithelial tissue and potently inhibits the neutrophil-derived serine proteases elastase and proteinase-3 by a competitive tight-binding mechanism. Furthermore, it inhibits EVE (endogenous vascular elastase). Studies on several animal models show that antiprotease augmentation with human elafin is an effective strategy in the treatment of inflammatory vascular, systemic and pulmonary diseases and of inflammation triggered by reperfusion injury. This raises the possibility that elafin might be effective in the treatment of a variety of human inflammatory diseases. In a Phase I clinical trial, elafin was well tolerated. Phase II trials are underway to investigate the therapeutic effects of elafin on post-operative inflammation and the clinical consequences of major surgery. Of particular interest is the reduction of post-operative morbidity after oesophagus cancer surgery, coronary artery bypass surgery and kidney transplantation.
Functional studies of eppin.
Source
Department of Cell and Developmental Biology and Laboratories for Reproductive Biology, University of North Carolina at Chapel Hill, NC 27599, USA. morand@unc.edu
Abstract
Our laboratory has characterized EPPIN [epididymal protease inhibitor; SPINLW1] as a novel gene on human chromosome 20q12-13.2, which encodes a cysteine-rich protein of 133 amino acids with a calculated molecular mass of 15.283 kDa, containing both Kunitz-type and WAP (whey acidic protein)-type four-disulfide core consensus sequences. Eppin is secreted by Sertoli cells in the testis and epididymal epithelial cells; it is predominantly a dimer, although multimers often exist, and in its native form eppin is found on the human sperm surface complexed with LTF (lactotransferrin) and clusterin. During ejaculation SEMG (semenogelin) from the seminal vesicles binds to the eppin protein complex, initiating a series of events that define eppin's function. Eppin's functions include (i) modulating PSA (prostate-specific antigen) enzyme activity, (ii) providing antimicrobial protection and (iii) binding SEMG thereby inhibiting sperm motility. As PSA hydrolyses SEMG in the ejaculate coagulum, spermatozoa gain progressive motility. We have demonstrated that eppin is essential for fertility because immunization of male monkeys with recombinant eppin results in complete, but reversible, contraception. To exploit our understanding of eppin's function, we are developing compounds that inhibit eppin-SEMG interaction and mimic anti-eppin, inhibiting sperm motility. These compounds should have potential as a male contraceptive.
SLPI and elafin: multifunctional antiproteases of the WFDC family.
Source
Centre for Infection and Immunity, Health Sciences Building, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
Abstract
SLPI (secretory leucoprotease inhibitor) and elafin represent the archetypal members of the WFDC [WAP (wheyacidic protein) four disulfide core] family of proteins, and were originally characterized as protease inhibitors but have since been shown to possess a wider repertoire of activities. These functions include antimicrobial and immunomodulatory properties, suggesting that these proteins may play key roles in the innate immune response, and indicate the potential to develop some of these proteins as novel therapeutics. Susceptibility to host and bacterial protease cleavage may, however, limit the efficacy of recombinant protein therapies in diseases with a high protease burden such as CF (cystic fibrosis) lung disease. To overcome this problem, further refinement of the native proteins will be required to provide effective treatment strategies.
War and peace between WAP and HIV: role of SLPI, trappin-2, elafin and ps20 in susceptibility to HIV infection.
Source
Michael G DeGroote Institute for Infectious Disease Research, Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4KI.
Abstract
Despite tremendous advances in our understanding of HIV/AIDS since the first cases were reported 30 years ago, we are still a long way from understanding critical steps of HIV acquisition, pathogenesis and correlates of protection. Our new understanding of the importance of the mucosa as a target for HIV infection, as well as our recent observations showing that altered expression and responses of innate pattern recognition receptors are significantly associated with pathogenesis and resistance to HIV infection, indicate that correlates of immunity to HIV are more likely to be associated with mucosal and innate responses. Most of the heterosexual encounters do not result in productive HIV infection, suggesting that the female genital tract is protected against HIV by innate defence molecules, such as antiproteases, secreted mucosally. The present review highlights the role and significance of the serine protease inhibitors SLPI (secretory leucocyte protease inhibitor), trappin-2, elafin and ps20 (prostate stromal protein 20 kDa) in HIV susceptibility and infection. Interestingly, in contrast with SLPI, trappin-2 and elafin, ps20 has been shown to enhance HIV infectivity. Thus understanding the balance and interaction of these factors in mucosal fluids may significantly influence HIV infection.
WAP domain proteins as modulators of mucosal immunity.
Source
Institute of Life Science, Microbiology and Infection, Floor 5, School of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, UK.
Abstract
WAP (whey acidic protein) is an important whey protein present in milk of mammals. This protein has characteristic domains, rich in cysteine residues, called 4-DSC (four-disulfide core domain). Other proteins, mainly present at mucosal surfaces, have been shown to also possess these characteristic WAP-4-DSC domains. The present review will focus on two WAP-4-DSC containing proteins, namely SLPI (secretory leucocyte protease inhibitor) and trappin-2/elafin. Although first described as antiproteases able to inhibit in particular host neutrophil proteases [NE (neutrophil elastase), cathepsin-G and proteinase-3] and as such, able to limit maladaptive tissue damage during inflammation, it has become apparent that these molecules have a variety of other functions (direct antimicrobial activity, bacterial opsonization, induction of adaptive immune responses, promotion of tissue repair, etc.). After providing information about the 'classical' antiproteasic role of these molecules, we will discuss the evidence pertaining to their pleiotropic functions in inflammation and immunity.
Genes encoding WFDC- and Kunitz-type protease inhibitor domains: are they related?
Source
Department of Laboratory Medicine, Skåne University Hospital, Lund University, SE-205 02 Malmö, Sweden. ake.lundwall@med.lu.se
Abstract
We have previously demonstrated that the genes of SCPs (semen coagulum proteins) and the WFDC (wheyacidic protein four-disulfide core)-type protease inhibitor elafin are homologous in spite of lacking similarity between their protein products. This led to the discovery of a locus on human chromosome 20, encompassing genes of the SCPs, SEMG1 (semenogelin I) and SEMG2, and 14 genes containing the sequence motif that is characteristic of WFDC-type protease inhibitors. We have now identified additional genes at the locus that are similarly organized, but which give rise to proteins containing the motif of Kunitz-type protease inhibitors. Here, we discuss the evolution of genes encoding SCPs and describe mechanisms by which they and genes with Kunitz motifs might have evolved from genes with WFDC motifs. We can also demonstrate an expansion of the WFDC locus with 0.6 Mb in the cow. The region, which seems to be specific to ruminants, contains several genes and pseudogenes with Kunitz motifs, one of which is the much-studied BPTI (bovine pancreatic trypsin inhibitor).
Review: Production and functionality of active peptides from milk.
Source
Department of Chemical Engineering and Investigation, Instituto Tecnológico de Toluca. Av. Tecnológico s/n Ex-Rancho la Virgen, Toluca, C.P. 52140, México. cmuro@ittolca.edu.mx
Abstract
In recent years, research on the production of active peptides obtained from milk and their potential functionality has grown, to a great extent. Bioactive peptides have been defined as specific protein fragments that have a positive impact on body functions or conditions, and they may ultimately have an influence on health. Individual proteins of casein or milk-derived products such as cheese and yogurt have been used as a protein source to study the isolation and activity of peptides with several applications. Currently, the milk whey waste obtained in the production of cheese also represents a protein source from which active peptides could be isolated with potential industrial applications. The active properties of milk peptides and the results found with regard to their physiological effects have led to the classification of peptides as belonging to the group of ingredients of protein nature, appropriate for use in functional foods or pharmaceutical formulations. In this study, the main peptidesobtained from milk protein and the past research studies about its production and biological activities will be explained. Second, an analysis will be made on the methods to determinate the biological activities, the separation of bioactive peptides and its structure identification. All of these form the base required to obtain synthetic peptides. Finally, we explain the experimental animal and human trials done in the past years. Nevertheless, more research is required on the design and implementation of equipment for the industrial production and separation of peptides. In addition, different authors suggest that more emphasis should therefore be given to preclinical studies, proving that results are consistent and that effects are demonstrated repeatedly by several research human groups.
- PMID:
- 21917640
- [PubMed - indexed for MEDLINE]
A comparative study of antimicrobial properties of crustinPm1 and crustinPm7 from the black tiger shrimp Penaeus monodon.
Source
Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. Kuakarun.K@chula.ac.th
Abstract
Several isoforms of crustin have been identified in the black tiger shrimp Penaeus monodon. These cationic cysteine-rich antimicrobial peptides contain a single whey acidic protein (WAP) domain at the C-terminus and exhibit antimicrobial activity against both Gram-positive and Gram-negative bacteria. In this paper, we investigate the binding properties and antimicrobial actions of crustinPm1 and crustinPm7, the two most abundant crustin isoforms found in the haemocyte of P. monodon. Previously, crustinPm1 showed strong inhibition against Gram-positive bacteria, whilst crustinPm7 acted against both Gram-positive and Gram-negative bacteria. A binding study showed that both crustins can bind to Gram-positive and Gram-negative bacterial cells. Enzyme-linked immunosorbent (ELISA) assay suggested that crustins bind to the cell wall components, lipoteichoic acid (LTA) and lipopolysaccharide (LPS) with positive cooperativity of Hill slope (H)>2. This indicates that at least two molecules of crustins interact with one LTA or LPS molecule. In addition, both crustins can induce bacterial agglutination and cause inner membrane permeabilization in Escherichia coli. Scanning Electron Microscopy (SEM) revealed the remarkable change on the cell surface of Staphylococcus aureus, Vibrio harveyi and E. coli after the bacteria were treated with the recombinant crustinPm7. Meanwhile, crustinPm1 can cause a visible change on the cell surface of S. aureus and E. coli only. This is in agreement with the fact that crustinPm1 has shown no antimicrobial activity against V. harveyi. It is likely that the antimicrobial activity of crustins mainly relies on their ability to agglutinate bacterial cells and to disrupt the physiochemical properties of bacterial surface.
Copyright © 2011 Elsevier Ltd. All rights reserved.
Structure modification of a milk protein-based model food affects postprandial intestinal peptide release and fullness in healthy young men.
Source
Department of Clinical Nutrition, Institute of Public Health and Clinical Nutrition, Food and Health Research Centre, University of Eastern Finland, 70211 Kuopio, Finland.
Abstract
Physico-chemical and textural properties of foods in addition to their chemical composition modify postprandial metabolism and signals from the gastrointestinal tract. Enzymatic cross-linking of protein is a tool to modify food texture and structure without changing nutritional composition. We investigated the effects of structure modification of a milk protein-based model food and the type of milk protein used on postprandial hormonal, metabolic and appetitive responses. Healthy males (n 8) consumed an isoenergetic and isovolumic test product containing either whey protein (Wh, low-viscous liquid), casein (Cas, high-viscous liquid) or Cas protein cross-linked with transglutaminase (Cas-TG, rigid gel) in a randomised order. Blood samples were drawn for plasma glucose, insulin, cholecystokinin (CCK), glucagon-like peptide 1 and peptide YY analysis for 4 h. Appetite was assessed at concomitant time points. Cas and Wh were more potent in lowering postprandial glucose than Cas-TG during the first hour. Insulin concentrations peaked at 30 min, but the peaks were more pronounced for Cas and Wh than for Cas-TG. The increase in CCK was similar for Cas and Wh in the first 15 min, whereas for Cas-TG, the CCK release was significantly lower, but more sustained. The feeling of fullness was stronger after the consumption of Cas-TG than after the consumption of Cas and Wh. The present results suggest that food structure is more effective in modulating the postprandial responses than the type of dairy protein used. Modification of protein-based food structure could thus offer a possible tool for lowering postprandial glucose and insulin concentrations and enhancing postprandial fullness.
Immunodetection of added glycomacropeptide in milk formulas and milk powders.
Source
Lucian Blaga University of Sibiu, Department of Biochemistry and Toxicology, Faculty of Agricultural Sciences, Food Industry and Environmental Protection, 7-9 Ion Ratiu Street, 550012 Sibiu, Romania. simona.oancea@ulbsibiu.ro
Abstract
The present study aimed the detection of fraudulent manipulation of milk powder with a low cost component--wheypowder, by applying the immunochromatographic assay to identify glycomacropeptide. Five commercial milk powder samples of various brands from the national market were analyzed: lactose enriched milk powder type 26, two whole milk powders, vitamin enriched milk powder and full cream milk powder. Our results showed additionalwhey (1-2%) in 60% of the selected samples after casein removal by precipitation with 20% trichloracetic acid. Another investigated sample--the enriched UHT milk for children aged 4-12 years--proved addition of whey. Other two commercial toddler formula milk powder samples of different brands were used for comparison for the presence of glycomacropeptide. The first sample which was regularly labeled as containing whey protein concentrate was found positive for glycomacropeptide in accordance with the label information, while the second one not containing whey proteins as specified by the product label, was found negative for glycomacropeptide, these two samples being in accordance with the actual legislation.
- PMID:
- 21717808
- [PubMed - indexed for MEDLINE]
Beneficial effects of resistance exercise on glycemic control are not further improved by protein ingestion.
Source
School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.
Abstract
PURPOSE:
To investigate the mechanisms underpinning modifications in glucose homeostasis and insulin sensitivity 24 h after a bout of resistance exercise (RE) with or without protein ingestion.
METHODS:
Twenty-four healthy males were assigned to a control (CON; n = 8), exercise (EX; n = 8) or exercise plus protein condition (EX+PRO; n = 8). Muscle biopsy and blood samples were obtained at rest for all groups and immediately post-RE (75% 1RM, 8×10 repetitions of leg-press and extension exercise) for EX and EX+PRO only. At 24 h post-RE (or post-resting biopsy for CON), a further muscle biopsy was obtained. Participants then consumed an oral glucose load (OGTT) containing 2 g of [U-¹³C] glucose during an infusion of 6, 6-[²H₂] glucose. Blood samples were obtained every 10 min for 2 h to determine glucose kinetics. EX+PRO ingested an additional 25 g of intact whey protein with the OGTT. A final biopsy sample was obtained at the end of the OGTT.
RESULTS:
Fasted plasma glucose and insulin were similar for all groups and were not different immediately post- and 24 h post-RE. Following RE, muscle glycogen was 26±8 and 19±6% lower in EX and EX+PRO, respectively. During OGTT, plasma glucose AUC was lower for EX and EX+PRO (75.1±2.7 and 75.3±2.8 mmol·L⁻¹∶120 min, respectively) compared with CON (90.6±4.1 mmol·L⁻¹∶120 min). Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO. Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON. Basal 24 h post-RE and insulin-stimulated PAS-AS160/TBC1D4 phosphorylation was greater for EX and EX+PRO.
CONCLUSIONS:
Prior RE improves glycemic control and insulin sensitivity through an increase in the rate at which glucose is disposed from the circulation. However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.
A new enteral diet, MHN-02, which contains abundant antioxidants andwhey peptide, protects against carbon tetrachloride-induced hepatitis.
Source
Department of Anesthesiology and Medical Crisis Management, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. ttakayan@live.jp
Abstract
BACKGROUND:
Inflammatory or oxidative stress is related to various diseases, including not only inflammatory diseases, but also diabetes, cancer, and atherosclerosis. The aim of this study was to evaluate the anti-inflammatory effects of a new enteral diet, MHN-02, which contains abundant antioxidants and whey peptide. The study also investigated the ability of MHN-02 to attenuate lethality, liver injury, the production of inflammatory cytokines, and the production of oxidized products using a carbon tetrachloride-induced rat model of severe fulminant hepatitis.
METHODS:
Male Sprague-Dawley rats were fed either a control diet or the MHN-02 diet for 14 days and injected with 2 mL/kg of carbon tetrachloride. Survival of rats was monitored from day 0 to day 3. To evaluate liver injury, inflammation, and oxidative stress, blood and liver samples were collected, and aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, interleukin 6, tumor necrosis factor-α, and superoxide dismutase activity as a free radical scavenger were measured. A portion of the liver was evaluated histologically.
RESULTS:
The survival rates of rats receiving the MHN-02 diet and the control diet were 90% and 55%, respectively. In the MHN-02 diet group, levels of serum liver enzymes and serum cytokines were significantly lower than in the control group. Superoxide dismutase activity in the MHN-02 diet was significantly higher in the MHN-02 group. Pathological lesions were significantly larger in the control group.
CONCLUSION:
Supplementation of enteral diets containing whey peptide and antioxidants may protect against severe hepatitis.
Poppea's bath liquor: the secret proteome of she-donkey's milk.
Source
Department of Chemical Sciences, University of Catania, Catania, Italy. vcunsolo@unict.it
Abstract
Donkey's milk is today categorized among the best mother's milk substitute for allergic newborns, due to its much reduced or absent allergenicity, coupled to excellent palatability and nutritional value. However, up to the present, only a handful of proteins had been characterized, just about the standard eight to ten major ones known in all types of milk. By exploiting the combinatorial peptide ligand library technology, and treating large volumes (up to 300 mL) of defatted, de-caseinized (whey) milk, we have been able to identify 106 unique gene products, by far the largest description so far of this precious nutrient. Due to poor knowledge of the donkey's genetic asset, only 10% of the proteins could be identified by consulting the data base of Equus asinus; the largest proportion (70%) could be identified by homology with the proteins of Equus caballus.
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