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Chen C, Shang C, Xin L, Xiang M, Wang Y, Shen Z, Jiao L, Ding F, Cui X. Beneficial Effects of Psyllium on the Prevention and Treatment of Cardiometabolic Diseases. Food Funct 2022; 13:7473-7486. [PMID: 35781477 DOI: 10.1039/d2fo00560c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cardiometabolic diseases are reaching epidemic proportions worldwide. Nevertheless, current therapeutic strategies are insufficient; thus, studying novel complementary and alternative medicines remains of the upmost importance. Psyllium has been used for...
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Affiliation(s)
- Chen Chen
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Chang Shang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Laiyun Xin
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
- First Clinical Medical School, Shandong University of Chinese Medicine, Shandong, 250355, China
| | - Mi Xiang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Yuling Wang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zihuan Shen
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Linke Jiao
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Fan Ding
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Xiangning Cui
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
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Comparison of polyphenol-rich wine grape seed flour-regulated fecal and blood microRNAs in high-fat, high-fructose diet-induced obese mice. J Funct Foods 2020. [DOI: 10.1016/j.jff.2020.104147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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3
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Momtazi-Borojeni AA, Katsiki N, Pirro M, Banach M, Rasadi KA, Sahebkar A. Dietary natural products as emerging lipoprotein(a)-lowering agents. J Cell Physiol 2019; 234:12581-12594. [PMID: 30637725 DOI: 10.1002/jcp.28134] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/07/2018] [Indexed: 12/13/2022]
Abstract
Elevated plasma lipoprotein(a) (Lp(a)) levels are associated with an increased risk of cardiovascular disease (CVD). Hitherto, niacin has been the drug of choice to reduce elevated Lp(a) levels in hyperlipidemic patients but its efficacy in reducing CVD outcomes has been seriously questioned by recent clinical trials. Additional drugs may reduce to some extent plasma Lp(a) levels but the lack of a specific therapeutic indication for Lp(a)-lowering limits profoundly reduce their use. An attractive therapeutic option is natural products. In several preclinical and clinical studies as well as meta-analyses, natural products, including l-carnitine, coenzyme Q 10 , and xuezhikang were shown to significantly decrease Lp(a) levels in patients with Lp(a) hyperlipoproteinemia. Other natural products, such as pectin, Ginkgo biloba, flaxseed, red wine, resveratrol and curcuminoids can also reduce elevated Lp(a) concentrations but to a lesser degree. In conclusion, aforementioned natural products may represent promising therapeutic agents for Lp(a) lowering.
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Affiliation(s)
- Amir Abbas Momtazi-Borojeni
- Department of Medical Biotechnology, Nanotechnology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Niki Katsiki
- Second Propedeutic Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, Hippocration Hospital, Thessaloniki, Greece
| | - Matteo Pirro
- Unit of Internal Medicine, Angiology and Arteriosclerosis Diseases, Department of Medicine, University of Perugia, Perugia, Italy
| | - Maciej Banach
- Department of Hypertension, WAM University Hospital in Lodz, Medical University of Lodz, Lodz, Poland.,Polish Mother's Memorial Hospital Research Institute, Lodz, Poland
| | - Khalid Al Rasadi
- Department of Clinical Biochemistry, Sultan Qaboos University Hospital, Muscat, Oman
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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Seo KH, Kim DH, Jeong D, Yokoyama W, Kim H. Chardonnay grape seed flour supplemented diets alter intestinal microbiota in diet-induced obese mice. J Food Biochem 2017. [DOI: 10.1111/jfbc.12396] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kun-Ho Seo
- KU Center for Food Safety, College of Veterinary Medicine; Konkuk University, Hwayang-dong; Gwangjin-gu Seoul South Korea
| | - Dong-Hyeon Kim
- KU Center for Food Safety, College of Veterinary Medicine; Konkuk University, Hwayang-dong; Gwangjin-gu Seoul South Korea
| | - Dana Jeong
- KU Center for Food Safety, College of Veterinary Medicine; Konkuk University, Hwayang-dong; Gwangjin-gu Seoul South Korea
| | | | - Hyunsook Kim
- Department of Food and Nutrition; Hanyang University; Seongdong-gu Seoul South Korea
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Chardonnay Grape Seed Flour Ameliorates Hepatic Steatosis and Insulin Resistance via Altered Hepatic Gene Expression for Oxidative Stress, Inflammation, and Lipid and Ceramide Synthesis in Diet-Induced Obese Mice. PLoS One 2016; 11:e0167680. [PMID: 27977712 PMCID: PMC5157984 DOI: 10.1371/journal.pone.0167680] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 11/18/2016] [Indexed: 01/04/2023] Open
Abstract
To identify differentially expressed hepatic genes contributing to the improvement of high-fat (HF) diet-induced hepatic steatosis and insulin resistance following supplementation of partially defatted flavonoid-rich Chardonnay grape seed flour (ChrSd), diet-induced obese (DIO) mice were fed HF diets containing either ChrSd or microcrystalline cellulose (MCC, control) for 5 weeks. The 2-h insulin area under the curve was significantly lowered by ChrSd, indicating that ChrSd improved insulin sensitivity. ChrSd intake also significantly reduced body weight gain, liver and adipose tissue weight, hepatic lipid content, and plasma low-density lipoprotein (LDL)-cholesterol, despite a significant increase in food intake. Exon microarray analysis of hepatic gene expression revealed down-regulation of genes related to triglyceride and ceramide synthesis, immune response, oxidative stress, and inflammation and upregulation of genes related to fatty acid oxidation, cholesterol, and bile acid synthesis. In conclusion, the effects of ChrSd supplementation in a HF diet on weight gain, insulin resistance, and progression of hepatic steatosis in DIO mice were associated with modulation of hepatic genes related to oxidative stress, inflammation, ceramide synthesis, and lipid and cholesterol metabolism.
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Flavonoid-rich Chardonnay grape seed flour supplementation ameliorates diet-induced visceral adiposity, insulin resistance, and glucose intolerance via altered adipose tissue gene expression. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.06.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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Kim H, Kim DH, Seo KH, Chon JW, Nah SY, Bartley GE, Arvik T, Lipson R, Yokoyama W. Modulation of the intestinal microbiota is associated with lower plasma cholesterol and weight gain in hamsters fed chardonnay grape seed flour. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:1460-1467. [PMID: 25598538 DOI: 10.1021/jf5026373] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The relationship between the intestinal microbiota and the hypocholesterolemic and antiobesity effects of whole grape seed flour from white and red winemaking was evaluated. Male Golden Syrian hamsters were fed a high-fat (HF) control diet or a HF diet supplemented with 10% partially defatted grape seed flours from either Chardonnay (ChrSd) or Cabernet Sauvignon (CabSd) grapes for 3 weeks. The numbers of total bacteria and relative abundances of Bifidobacterium spp., Lactobacillus spp., and Firmicutes in feces were significantly lower, while the relative abundance of Bacteroides fragilis was greater than the control from feeding the ChrSd diet. The ratio of Firmicutes/Bacteroidetes (F/B) was lower in the ChrSd diet. There were significantly positive correlations between Lactobacillus spp., ratio of F/B, and plasma total- and LDL-cholesterol and liver weight. The reduction of Lactobacillus spp. by the ChrSd diet was accompanied by inhibition of Farnesoid X receptor (FXR) signaling in the intestine as expression of intestinal fibrablast growth factor (FGF)15, positively regulated by FXR, was decreased. Expression of CYP7A1, negatively regulated by FGF15, was up-regulated in the liver, which indicates that alteration of the intestinal microbiota may regulate bile acid and lipid metabolism. These findings suggest that beneficial health effects of Chardonnay grape seed flour on HF-induced metabolic disease relate in part to modulation of intestinal microbiota and their metabolic processes.
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Affiliation(s)
- Hyunsook Kim
- Department of Nutrition, UC Davis , Davis, California 95616, United States
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Kim H, Bartley GE, Arvik T, Lipson R, Nah SY, Seo K, Yokoyama W. Dietary supplementation of chardonnay grape seed flour reduces plasma cholesterol concentration, hepatic steatosis, and abdominal fat content in high-fat diet-induced obese hamsters. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:1919-1925. [PMID: 24517872 DOI: 10.1021/jf404832s] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The mechanisms for the hypocholesterolemic and antiobesity effects of grape seed flours derived from white and red winemaking processing were investigated using male Golden Syrian hamsters fed high-fat (HF) diets supplemented with 10% partially defatted grape seed flours from Chardonnay (ChrSd), Cabernet Sauvignon (CabSd), or Syrah (SyrSd) pomace as compared to a HF control diet for 3 weeks. Hamsters fed the ChrSd diet had significantly lowered plasma total-, VLDL-, and LDL-cholesterol concentrations compared to the CabSd, SyrSd, and control diets. The improved plasma cholesterol after ChrSd was correlated with the up-regulation of hepatic genes related to cholesterol (CYP51) and bile acid (CYP7A1) synthesis as well as LDL-cholesterol uptake (LDLR). A reduction of hepatic lipid content was associated with altered expression of the genes related to lipid metabolism. However, fecal total lipid content was not changed. Expression of ileal apical sodium bile acid transporter (ASBT) was not affected by ChrSd, indicating unchanged ileal bile acid reabsorption. The antiobesity effect of the ChrSd diet appears to be related to expression of adipogenesis- and inflammation-related genes in adipose tissue. These findings suggest that flavonoid-rich Chardonnay grape seed flour induced cholesterol-lowering, antiobesity, and anti-inflammatory health benefits and attenuation of hepatic steatosis via regulation of gene expression related to cholesterol, bile acid, and lipid metabolism in liver and adipose tissue.
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Affiliation(s)
- Hyunsook Kim
- Department of Nutrition, University of California, Davis, California 95616, United States
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Characterization of Psyllium (Plantago ovata) Polysaccharide and Its Uses. POLYSACCHARIDES 2014. [DOI: 10.1007/978-3-319-03751-6_49-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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11
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Kim H, Bartley GE, Young SA, Seo KH, Yokoyama W. Altered hepatic gene expression profiles associated with improved fatty liver, insulin resistance, and intestinal permeability after hydroxypropyl methylcellulose (HPMC) supplementation in diet-induced obese mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:6404-6411. [PMID: 23742138 DOI: 10.1021/jf400545w] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The effect of hydroxypropyl methylcellulose (HPMC) on hepatic gene expression was analyzed by exon microarray and real-time PCR from livers of diet-induced obese (DIO) mice fed a high-fat (HF) diet supplemented with either 6% HPMC or 6% microcrystalline cellulose (MCC). HPMC-fed mice exhibited significantly reduced body weight gain (55% lower compared to MCC), liver weight (13%), plasma LDL-cholesterol concentration (45%), and HF diet-increased intestinal permeability (48%). HPMC significantly reduced areas under the curve for 2 h insulin and glucose responses, indicating enhanced insulin sensitivity and glucose metabolism. HPMC up-regulated hepatic genes related to fatty acid oxidation, cholesterol and bile acid synthesis, and cellular activation of glucocorticoid (bile acid recycling) and down-regulated genes related to oxidative stress, triglyceride synthesis, and polyunsaturated fatty acid elongation. In conclusion, HPMC consumption ameliorates the effects of a HF diet on intestinal permeability, insulin resistance, hepatic lipid accumulation, glucocorticoid-related bile acid recycling, oxidative stress, and weight gain in DIO mice.
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Affiliation(s)
- Hyunsook Kim
- Department of Nutrition, University of California, Davis, California 95616, USA.
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Hung SC, Yokoyama W, Kim H, Bartley G, Anderson WHK, Albers DR, Langhorst ML, Williams DM, Stott W, Turowski M, Young SA. Effects of cationic hydroxyethyl cellulose on dyslipidemia in hamsters. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:11149-11156. [PMID: 23083223 DOI: 10.1021/jf302095c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Cationic hydroxyethyl cellulose (cHEC) was supplemented in a high-fat diet to determine if this new soluble fiber had an effect on hypercholesterolemia and dyslipidemia associated with cardiovascular disease using Golden Syrian hamster as an animal model. Supplementation of 3-5% cHEC in a high-fat diet for 4 weeks led to significant weight gain reduction in hamsters. In addition, significant decreases in adipose and liver weights, concentrations of plasma total, VLDL, and LDL cholesterol, and hepatic lipids were shown. No significant improvements in glucose and insulin levels were observed with cHEC; however, a significant increase in plasma adiponectin and a decrease in leptin were observed. As compared with controls, 8% cHEC-fed hamsters had greater levels of mRNA for CYP7A1 (cytochrome P450 7A1; 2-fold of control; P < 0.05), CYP51 (lanosterol 14α-demethylase; 6-fold of control; P < 0.05), and LDLR (LDL receptor; 1.5-fold of control) in the liver. These findings suggest the possibility of the use of cHEC for cholesterol reduction and beneficial effects on the cardiovascular risk factors.
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Kim H, Bartley GE, Young SA, Davis PA, Yokoyama W. HPMC supplementation reduces abdominal fat content, intestinal permeability, inflammation, and insulin resistance in diet-induced obese mice. Mol Nutr Food Res 2012; 56:1464-76. [DOI: 10.1002/mnfr.201200082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/20/2012] [Accepted: 05/18/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Hyunsook Kim
- Department of Nutrition; University of California; Davis CA USA
- USDA, ARS; Western Regional Research Center; Albany CA USA
| | | | | | - Paul A. Davis
- Department of Nutrition; University of California; Davis CA USA
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Mandimika T, Paturi G, De Guzman CE, Butts CA, Nones K, Monro JA, Butler RC, Joyce NI, Mishra S, Ansell J. Effects of dietary broccoli fibre and corn oil on serum lipids, faecal bile acid excretion and hepatic gene expression in rats. Food Chem 2012. [DOI: 10.1016/j.foodchem.2011.09.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yasukawa Z, Naito Y, Takagi T, Mizushima K, Tokunaga M, Ishihara N, R Juneja L, Yoshikawa T. Partially hydrolyzed guar gum affects the expression of genes involved in host defense functions and cholesterol absorption in colonic mucosa of db/db male mice. J Clin Biochem Nutr 2011; 51:33-8. [PMID: 22798710 PMCID: PMC3389045 DOI: 10.3164/jcbn.11-104] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 08/15/2011] [Indexed: 12/11/2022] Open
Abstract
Biomedical evidence in the last 20 years has shown that the consumption of partially hydrolyzed guar gum may influence lipid and/or carbohydrate metabolism at many levels. Since intestine represents the first interface to interact with dietary partially hydrolyzed guar gum in vivo, we evaluated gene expression profiles in small intestinal mucosa of db/db mice fed with partially hydrolyzed guar gum in an effort to delineate its effect on the small intestine. DNA microarray and real-time PCR analyses were performed to evaluate the gene expression profiles in mice small intestinal mucosa. Among the 28,853 transcripts represented on the GeneChip® microarray, no more than 20 genes exhibited up- or down-regulation by 1.5-fold or more after four weeks following partially hydrolyzed guar gum consumption. No adverse effects were apparent. We detected up- or down-regulation of some genes known to be involved in host defense functions and cholesterol absorption.
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Affiliation(s)
- Zenta Yasukawa
- Nutrition Division, Taiyo Kagaku Co. Ltd., 1-3 Takaramachi, Yokkaichi 510-0844, Japan
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Abstract
Elevated total and low-density lipoprotein (LDL) cholesterol levels are considered major risk factors for cardiovascular disease. Oat β-glucan, a soluble dietary fiber that is found in the endosperm cell walls of oats, has generated considerable interest due to its cholesterol-lowering properties. The United States Food and Drug Administration (FDA) approved a health claim for β-glucan soluble fiber from oats for reducing plasma cholesterol levels and risk of heart disease in 1997. Similarly, in 2004 the United Kingdom Joint Health Claims Initiative (JHCI) allowed a cholesterol-lowering health claim for oat β-glucan. The present review aims to investigate if results from more recent studies are consistent with the original conclusions reached by the FDA and JHCI. Results of this analysis show that studies conducted during the past 13 years support the suggestion that intake of oat β-glucan at daily doses of at least 3 g may reduce plasma total and low-density lipoprotein (LDL) cholesterol levels by 5-10% in normocholesterolemic or hypercholesterolemic subjects. Studies described herein have shown that, on average, oat consumption is associated with 5% and 7% reductions in total and LDL cholesterol levels, respectively. Significant scientific agreement continues to support a relationship between oat β-glucan and blood cholesterol levels, with newer data being consistent with earlier conclusions made by the FDA and JHCI.
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Affiliation(s)
- Rgia A Othman
- Department of Human Nutritional Sciences and Canadian Centre for Agri-food Research in Health and Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
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Kim H, Turowski M, Anderson WHK, Young SA, Kim Y, Yokoyama W. Supplementation of hydroxypropyl methylcellulose into yeast leavened all-whole grain barley bread potentiates cholesterol-lowering effect. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:7672-7678. [PMID: 21671634 DOI: 10.1021/jf104821b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We investigated in Syrian Golden hamsters the biological impact and its underlying mechanism of single whole grain breads supplemented with 2-3% hydroxypropyl methylcellulose (HPMC), a semisynthetic viscous soluble dietary fiber (SDF) as a substitute for gluten. Hamsters were fed high-fat diets supplemented with 48-65% (w/w) differently ground, freeze-dried single grain breads including whole grain wheat, barley, barley supplemented with HPMC, debranned oat, and oat supplemented with HPMC which were compared to a diet containing microcrystalline cellulose (control). All single grain breads significantly lowered plasma LDL-cholesterol concentrations compared to the control. Enrichment with HPMC further lowered plasma and hepatic cholesterol concentrations. Despite the reduced molecular weight of naturally occurring soluble (1--->3),(1--->4)-β-d-glucan (β-glucan) caused by the bread-making process, whole grain barley breads downregulated hepatic expression of CYP7A1 and HMG-CoAR genes that are responsible for bile acid and cholesterol synthesis, suggesting a possible role of bioactive compounds such as short-chain fatty acids and phenolic compounds from barley bread. Barley bread enriched with HPMC downregulated expression of ABCG5 gene. Taken together, it appears that distinctive modulation of synthesis and excretion of hepatic cholesterol and bile acid contributes to the cholesterol-lowering properties of whole grain barley breads and breads enriched with HPMC. These data suggests that alternative whole grain breads supplemented with HPMC may provide consumers with a staple food that can assist in cholesterol management.
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Affiliation(s)
- Hyunsook Kim
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA.
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Lucas EA, Mahajan SS, Soung DY, Lightfoot SA, Smith BJ, Arjmandi BH. Flaxseed but Not Flaxseed Oil Prevented the Rise in Serum Cholesterol Due to Ovariectomy in the Golden Syrian Hamsters. J Med Food 2011; 14:261-7. [DOI: 10.1089/jmf.2009.0192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Edralin A. Lucas
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Sachin S. Mahajan
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Do Y. Soung
- Department of Orthopaedic Surgery, New England Musculoskeletal Institute, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Stanley A. Lightfoot
- Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Brenda J. Smith
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Bahram H. Arjmandi
- Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, Florida, USA
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Bartley GE, Yokoyama W, Young SA, Anderson WHK, Hung SC, Albers DR, Langhorst ML, Kim H. Hypocholesterolemic effects of hydroxypropyl methylcellulose are mediated by altered gene expression in hepatic bile and cholesterol pathways of male hamsters. J Nutr 2010; 140:1255-60. [PMID: 20444951 DOI: 10.3945/jn.109.118349] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Hydroxypropyl methylcellulose (HPMC), a semisynthetic, nonfermentable soluble dietary fiber, is not absorbed by the body, but its presence in the intestinal lumen increases fecal fat, sterol, and bile acid excretions and decreases intestinal cholesterol absorption, all of which may indirectly affect hepatic lipid metabolism. We measured the expression of hepatic genes involved in cholesterol, bile acid, and fatty acid metabolism in hamsters fed diets containing 39% of energy as fat and 5% of weight as HPMC or microcrystalline cellulose (control) for 4 wk. HPMC-fed hamsters gained significantly less body weight than the control group but did not differ in food intake. They had significantly lower plasma triglyceride and total-, VLDL-, HDL-, and LDL-cholesterol concentrations and hepatic total lipid, total and free cholesterol and triglyceride concentrations than controls. Compared with controls, HPMC-fed hamsters had greater levels of mRNA for CYP7A1 (cytochrome P450 7A1; 8-fold of control; P < 0.05), CYP51 (lanosterol 14alpha-demethylase; 5.3-fold of control; P < 0.05), and HMG-CoAR (3-hydroxy-3-methylglutaryl CoA reductase; 1.8-fold of control; P < 0.05). The plasma total cholesterol concentrations from both the control and HPMC groups were inversely correlated with expression of hepatic CYP7A1 (r = -0.54; P < 0.05), CYP51 (r = -0.79; P < 0.005), and HMG-CoAR (r = -0.75; P < 0.005) genes. This suggests that HPMC supplementation affected both cholesterol and bile acid synthesis. Our data confirm that altered hepatic expression of lipid metabolism-related genes, possibly due to modulation of fecal bile acid excretion and intestinal cholesterol absorption, contributes to the lipid-lowering effects of HPMC.
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Affiliation(s)
- Glenn E Bartley
- Processed Foods Research, Western Regional Research Center, USDA, Agricultural Research Service, Albany, CA 94710, USA
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Kim H, Bartley GE, Rimando AM, Yokoyama W. Hepatic gene expression related to lower plasma cholesterol in hamsters fed high-fat diets supplemented with blueberry peels and peel extract. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:3984-3991. [PMID: 20143813 DOI: 10.1021/jf903230s] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study analyzed plasma lipid profiles, genes related to cholesterol and bile acid metabolism, and inflammation in liver as well as adipose tissue from Syrian Golden hamsters fed high-fat diets supplemented with blueberry (BB) pomace byproducts including 8% dried whole blueberry peels (BBPWHL), 2% dried extract of peels (BBPX; 95% ethanol extract), and 6% residue from extracted peel (BBPEXT) compared to a diet containing 5% (w/w) microcrystalline cellulose (control). All BB diets significantly lowered plasma very low density lipoprotein cholesterol and total cholesterol concentrations. Interestingly, BB diets increased fecal lipid excretion. Hepatic CYP7A1 expression was up-regulated by all BB diets, and the expression of CYP51 was up-regulated by BBPX and BBPEXT diets, suggesting that both bile acid and cholesterol synthesis were increased. No significant changes in adipocyte gene expression related to inflammatory markers were observed with any BB diet. These data suggest that hepatic modulation of bile acid and cholesterol synthesis primarily contributes to the cholesterol-lowering effect of BB pomace byproducts.
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Affiliation(s)
- Hyunsook Kim
- Processed Foods Research, Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, Calfifornia 94710, USA.
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Papathanasopoulos A, Camilleri M. Dietary fiber supplements: effects in obesity and metabolic syndrome and relationship to gastrointestinal functions. Gastroenterology 2010; 138:65-72.e1-2. [PMID: 19931537 PMCID: PMC2903728 DOI: 10.1053/j.gastro.2009.11.045] [Citation(s) in RCA: 205] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Dietary fiber is a term that reflects a heterogeneous group of natural food sources, processed grains, and commercial supplements. Several forms of dietary fiber have been used as complementary or alternative agents in the management of manifestations of the metabolic syndrome, including obesity. Not surprisingly, there is a great variation in the biological efficacy of dietary fiber in the metabolic syndrome and body weight control. Diverse factors and mechanisms have been reported as mediators of the effects of dietary fiber on the metabolic syndrome and obesity. Among this array of mechanisms, the modulation of gastric sensorimotor influences appears to be crucial for the effects of dietary fiber but also quite variable. This report focuses on the role, mechanism of action, and benefits of different forms of fiber and supplements on obesity and the metabolic syndrome, glycemia, dyslipidemia, and cardiovascular risk and explores the effects of dietary fiber on gastric sensorimotor function and satiety in mediating these actions of dietary fiber.
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Rideout TC, Harding SV, Jones PJ, Fan MZ. Guar gum and similar soluble fibers in the regulation of cholesterol metabolism: current understandings and future research priorities. Vasc Health Risk Manag 2009; 4:1023-33. [PMID: 19183750 PMCID: PMC2605338 DOI: 10.2147/vhrm.s3512] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The hypocholesterolemic effects associated with soluble fiber consumption are clear from animal model and human clinical investigations. Moreover, the modulation of whole-body cholesterol metabolism in response to dietary fiber consumption, including intestinal cholesterol absorption and fecal sterol and bile acid loss, has been the subject of many published reports. However, our understanding of how dietary fibers regulate molecular events at the gene/protein level and alter cellular cholesterol metabolism is limited. The modern emphasis on molecular nutrition and rapid progress in 'high-dimensional' biological techniques will permit further explorations of the role of genetic polymorphisms in determining the variable interindividual responses to soluble fibers. Furthermore, with traditional molecular biology tools and the application of 'omic' technology, specific insight into how fibers modulate the expression of genes and proteins that regulate intestinal cholesterol absorption and alter hepatic sterol balance will be gained. Detailed knowledge of the molecular mechanisms by which soluble fibers reduce plasma cholesterol concentrations is paramount to developing novel fiber-based "cocktails" that target specific metabolic pathways to gain maximal cholesterol reductions.
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Affiliation(s)
- Todd C Rideout
- Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Manitoba, Canada.
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Hughes SA, Shewry PR, Gibson GR, McCleary BV, Rastall RA. In vitro fermentation of oat and barley derived beta-glucans by human faecal microbiota. FEMS Microbiol Ecol 2008; 64:482-93. [PMID: 18430007 DOI: 10.1111/j.1574-6941.2008.00478.x] [Citation(s) in RCA: 200] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Fermentation of beta-glucan fractions from barley [average molecular mass (MM), of 243, 172, and 137 kDa] and oats (average MM of 230 and 150 kDa) by the human faecal microbiota was investigated. Fractions were supplemented to pH-controlled anaerobic batch culture fermenters inoculated with human faecal samples from three donors, in triplicate, for each substrate. Microbiota changes were monitored by fluorescent in situ hybridization; groups enumerated were: Bifidobacterium genus, Bacteroides and Prevotella group, Clostridium histolyticum subgroup, Ruminococcus-Eubacterium-Clostridium (REC) cluster, Lactobacillus-Enterococcus group, Atopobium cluster, and clostridial cluster IX. Short-chain fatty acids and lactic acid were measured by HPLC. The C. histolyticum subgroup increased significantly in all vessels and clostridial cluster IX maintained high populations with all fractions. The Bacteroides-Prevotella group increased with all but the 243-kDa barley and 230-kDa oat substrates. In general beta-glucans displayed no apparent prebiotic potential. The SCFA profile (51 : 32 : 17; acetate : propionate : butyrate) was considered propionate-rich. In a further study a beta-glucan oligosaccharide fraction was produced with a degree of polymerization of 3-4. This fraction was supplemented to small-scale faecal batch cultures and gave significant increases in the Lactobacillus-Enterococcus group; however, the prebiotic potential of this fraction was marginal compared with that of inulin.
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Affiliation(s)
- Simon A Hughes
- Department of Food Biosciences, The University of Reading, Berkshire, UK
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Galisteo M, Duarte J, Zarzuelo A. Effects of dietary fibers on disturbances clustered in the metabolic syndrome. J Nutr Biochem 2008; 19:71-84. [PMID: 17618108 DOI: 10.1016/j.jnutbio.2007.02.009] [Citation(s) in RCA: 291] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 02/14/2007] [Indexed: 12/19/2022]
Abstract
Because of its growing prevalence in Western countries, the metabolic syndrome, a common metabolic disorder that clusters a constellation of abnormalities, including central obesity, hypertension, dyslipidemia and insulin resistance, is emerging as one of the most important public health problems in the world, taking into account that it is a major risk factor mainly for type 2 diabetes and cardiovascular diseases, and also for many types of cancer. Although the pathogenesis of this syndrome is complex and not fully understood, obesity and insulin resistance, accompanied by an altered profile of number of hormones and cytokines produced by the adipose tissue, seem to be the main causative agents. A prime therapeutic approach to the prevention and treatment of this syndrome involves lifestyle changes. Among dietary modifications, dietary fiber intake could play an interesting role in the management of metabolic syndrome through different mechanisms related to its dietary sources, specific chemical structure and physical properties, or fermentability in the gut. According to all of these variables, the different types of dietary fibers have been reported to take part in the control of body weight, glucose and lipid homeostasis, insulin sensitivity and in the regulation of many inflammation markers involved in the pathogenesis of metabolic syndrome, and which are also considered to be among its features.
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Affiliation(s)
- Milagros Galisteo
- Department of Pharmacology, CIBEREHD, School of Pharmacy, University of Granada, 18071 Granada, Spain.
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Yao L, Horn PS, Heubi JE, Woollett LA. The liver plays a key role in whole body sterol accretion of the neonatal Golden Syrian hamster. BIOCHIMICA ET BIOPHYSICA ACTA 2007; 1771:550-7. [PMID: 17363324 PMCID: PMC1905147 DOI: 10.1016/j.bbalip.2007.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 01/25/2007] [Accepted: 01/31/2007] [Indexed: 10/23/2022]
Abstract
Neonates have a significant requirement for cholesterol. From -1 to 25 days of age, the liver accrues 6.9 mg cholesterol and the extra-hepatic tissues accrue 107.7 mg cholesterol in the hamster. It is currently unknown if each of these body compartments synthesizes their own cholesterol or if they have alternative source(s) of sterol. Using (3)H(2)O, in vivo hepatic sterol synthesis rates (per g liver per animal) increased between -1 and 5 days of age, decreased by 10 days of age, and increased again by 15 days of age. HMG-CoA reductase (HMGR) expression levels paralleled in vivo synthesis rates. Extra-hepatic sterol synthesis rates followed the same pattern as sterol synthesis rates in the liver. When sterol synthesis rates were converted to the mass of sterol synthesized per day, the liver synthesized 38.9 and the extra-hepatic tissues synthesized 63.9 mg cholesterol in the 26-day neonatal period. Comparing the amount of cholesterol accrued to that synthesized, one can conclude that the liver is a major source of sterol for the whole body during the neonatal period of the hamster. These results may help elucidate the cause(s) of reduced growth rates in neonates with liver disease or in neonates with compromised sterol synthesis rates.
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Affiliation(s)
- Lihang Yao
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH
| | - Paul S. Horn
- Department of Mathematics, University of Cincinnati, Cincinnati, OH
| | - James E. Heubi
- Division of Pediatric Gastroenterology/Hepatology and Nutrition, Department of Pediatrics, General Clinical Research Center, Children's Hospital Medical Center, Cincinnati, OH
| | - Laura A. Woollett
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH
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Dietary rhubarb (Rheum rhaponticum) stalk fibre stimulates cholesterol 7α-hydroxylase gene expression and bile acid excretion in cholesterol-fed C57BL/6J mice. Br J Nutr 2007. [DOI: 10.1017/s0007114599000161] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Both experimental and clinical studies have indicated that a novel source of dietary fibre, produced from rhubarb (Rheum rhaponticum) stalks, is potentially hypolipidaemic. The present study, using C57BL/6J mice, was undertaken to examine if this fibre source affects cholesterol degradation. Mice were maintained on semi-purified diets containing 50 g rhubarb fibre or cellulose/kg with or without 5 g cholesterol/kg for 4 weeks. In cholesterol-supplemented mice, rhubarb fibre caused significant lowering of plasma cholesterol (-13 %) and the hepatic concentrations of total cholesterol (-34 %) and cholesteryl esters (-34 %). In parallel to the reduction of hepatic cholesteryl ester content, animals fed on rhubarb fibre had significantly lower activity of acyl CoA: cholesterol acyltransferase (EC 2.3.1.26) than the mice maintained on a diet containing cellulose and cholesterol. Rhubarb-fibre feeding accelerated the faecal bile-acid loss and diminished the gall-bladder bile-acid pool in both the normal and the cholesterol-fed mice. The increase in the bile-acid excretion was positively correlated with an increased activity as well as mRNA abundance of cholesterol 7α-hydroxylase (EC 1.14.13.17). The increased excretion of bile acids and induction of cholesterol 7α-hydroxylase activity may account for the hypocholesterolaemic effect of rhubarb fibre.
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Rideout TC, Yuan Z, Bakovic M, Liu Q, Li RK, Mine Y, Fan MZ. Guar gum consumption increases hepatic nuclear SREBP2 and LDL receptor expression in pigs fed an atherogenic diet. J Nutr 2007; 137:568-72. [PMID: 17311941 DOI: 10.1093/jn/137.3.568] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
To gain insight into the regulation of hepatic sterol-responsive genes that are thought to mediate the hypocholesterolemic effects of guar gum (GG) consumption, the mRNA and protein expression of sterol regulatory element binding protein 2 (SREBP2), LDL receptor (LDLr), and scavenger receptor class B, type 1 (SR-B1) were examined in pigs consuming an atherogenic control diet or the control diet supplemented with 10% GG. Compared with the control group, GG consumption reduced (P < 0.05) plasma total cholesterol and LDL cholesterol concentrations by 27 and 37%, respectively. Furthermore, hepatic free cholesterol concentration was lower (P < 0.05) in the GG-fed pigs in comparison with the control group. GG consumption increased hepatic LDLr mRNA (1.5-fold of the control, P = 0.09) and protein (2-fold of the control, P < 0.05) expression in comparison with the control group. However, GG consumption reduced hepatic SR-B1 mRNA to 36% of the control (P < 0.05) expression but did not affect (P = 0.19) SR-B1 protein abundance in comparison with the control group. Although SREBP2 mRNA expression was similar (P = 0.89) in the 2 groups, GG consumption increased (P < 0.05) the expression of the cytoplasmic precursor (3-fold of the control) and nuclear active forms (1.5-fold of the control) of SREBP2. We conclude that the hypocholesterolemic effects of GG consumption are related to a reduction in hepatic free cholesterol concentration and associated increases in nuclear active SREBP2 expression and hepatic LDLr abundance.
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Affiliation(s)
- Todd C Rideout
- Centre for Nutrition Modelling, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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Pellizzon MA, Billheimer JT, Bloedon LT, Szapary PO, Rader DJ. Flaxseed Reduces Plasma Cholesterol Levels in Hypercholesterolemic Mouse Models. J Am Coll Nutr 2007; 26:66-75. [PMID: 17353585 DOI: 10.1080/07315724.2007.10719587] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE We examined the effects of whole ground flaxseed added to a Western diet on plasma and hepatic lipids and hepatic gene expression in male and female human apolipoprotein B-100 transgenic (hApoBtg) mice which have a plasma lipid profile more closely resembling man than wild type mice and in mice lacking the low density lipoprotein receptor (LDLr) and apolipoprotein B mRNA editing enzyme complex 1 (LDLr(-/-)/apobec(-/-)). METHODS The Westernized control diet containing 0.1% cholesterol and 30% kcal as fat was fed for 10 days to hApoBtg mice and for 14 days to LDLr(-/-)/apobec(-/-) mice. Animals from each genetic background were then divided into 2 groups based on gender and mean plasma total cholesterol (TC). The hApoBtg and LDLr(-/-)/apobec(-/-) mice either continued on the control diet for a total of 31 and 35 days, respectively or were fed 20% w/w whole ground flaxseed (flax) with comparable caloric, macronutrient and fiber content for 21 days. Blood was obtained after a 4 hour fast from all mice prior to feeding both control and flax diets, after 10 days on the flax diet, and after 21 days on the flax at which time all mice were exsanguinated. RESULTS The control diet increased TC by >100 mg/dl in the hApoBtg with a greater increase observed in males and by 800 mg/dl in mice lacking the LDLr. After 3 weeks, the flax diet significantly reduced plasma TC by 19% and 22% in hApoBtg and LDLr(-/-)/apobec(-/-), respectively and non-high density lipoprotein cholesterol (non-HDL-C) by 24% in both models (p for all <0.05). Flax significantly reduced hepatic cholesterol in hApoBtg by 32% and 47% in males and females, respectively and LDLr(-/-)/apobec(-/-) mice by 66%. Flax had no effect on the expression of the following hepatic genes: LDLr, 3-hydroxy-3-methylglutaryl (HMG) CoA reductase, phospholipid transfer protein, cholesterol 7alpha hydroxylase, fatty acid synthase, and acyl CoA oxidase in either mouse model. CONCLUSIONS Flaxseed reduces plasma and hepatic cholesterol in hApoBtg mice, but had no effect on hepatic lipogenic genes and was equally effective in mice lacking LDLr. The combined data suggest that the lipid lowering effect of flax is not hepatic mediated and may be at the level of cholesterol absorption and/or bile acid reabsorption.
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Affiliation(s)
- Michael A Pellizzon
- M.D., Center for Experimental Therapeutics, University of Pennsylvania School of Medicine, 421 Curie Blvd., BRB II/III, Philadelphia, PA 19104-6160, USA
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29
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Liu YC, Liu SY, Lin MH. Effects of Psyllium on Plasma Total and Lipoprotein Cholesterol and Hepatic Cholesterol in Hamsters Fed n–3 PUFA or n–6 PUFA with High Cholesterol Levels. ANNALS OF NUTRITION AND METABOLISM 2004; 48:374-80. [PMID: 15564767 DOI: 10.1159/000082250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Accepted: 09/22/2004] [Indexed: 11/19/2022]
Abstract
This study was conducted to determine whether psyllium is known to alter cholesterol metabolism modulate the hypercholesterolemic effect of a high cholesterol, n-3 polyunsaturated fatty acids (PUFA) diet in hamsters. Concentrations of plasma, hepatic total cholesterol and lipoprotein cholesterol were measured in male hamsters fed an n-3 PUFA plus psyllium (8%, wt/wt) diet combined with variable levels of cholesterol (0, 0.05, 0.1%, wt/wt) or a cholesterol-enriched (0.2%, wt/wt) n-3 PUFA or n-6 PUFA diet that contained either 8% methyl cellulose or psyllium for 4 weeks. In the n-3 PUFA-fed hamsters, we have found that psyllium was able to reduce plasma total cholesterol and low density lipoprotein (LDL)-cholesterol significantly when 0.1% cholesterol was added to the diet. In contrast, the effects of psyllium were not seen in the n-3 PUFA-fed hamsters without dietary cholesterol or with 0.05% dietary cholesterol. However, no matter in the presence of psyllium or not, the increase of plasma total cholesterol, very-low-density lipoprotein (VLDL)-cholesterol, LDL-cholesterol and high-density lipoprotein (HDL)-cholesterol levels was depend on the content of dietary cholesterol. Although the cholesterol diet increased the liver total cholesterol level, 80 g psyllium/kg diet resulted in a significantly lower concentration of liver total cholesterol in the cholesterol-fed hamsters. In the second experiment, we have also found that psyllium feeding lowered significantly plasma total cholesterol and VLDL-cholesterol concentrations in hamsters fed n-3 PUFA but not in those fed n-6 PUFA. However, the levels of plasma total cholesterol, VLDL-cholesterol and LDL-cholesterol levels of the (n-6) PUFA-fed hamsters were significantly lower than those in the (n-3) PUFA-fed hamsters in the absence or presence of dietary psyllium. Our data also showed that hamsters fed both high-cholesterol n-3 PUFA and n-6 PUFA diets had a significant decrease in hepatic cholesterol with intake of psyllium. Liver total cholesterol concentrations were significantly lower in n-3 PUFA-fed hamsters compared with the n-6 PUFA-fed groups. Therefore, these data may contribute to understanding the interactive effect of psyllium and cholesterol or the type of fat on plasma and liver cholesterol in hamsters.
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MESH Headings
- Animals
- Cathartics/administration & dosage
- Cathartics/pharmacology
- Cholesterol/blood
- Cholesterol/metabolism
- Cholesterol, Dietary/administration & dosage
- Cholesterol, HDL/blood
- Cholesterol, HDL/metabolism
- Cholesterol, LDL/blood
- Cholesterol, LDL/metabolism
- Cholesterol, VLDL/blood
- Cholesterol, VLDL/metabolism
- Cricetinae
- Dose-Response Relationship, Drug
- Fatty Acids, Omega-3/administration & dosage
- Fatty Acids, Omega-3/metabolism
- Fatty Acids, Omega-6/administration & dosage
- Fatty Acids, Omega-6/metabolism
- Lipoproteins/blood
- Lipoproteins/metabolism
- Liver/metabolism
- Male
- Mesocricetus
- Psyllium/administration & dosage
- Psyllium/pharmacology
- Random Allocation
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Affiliation(s)
- Young-Chau Liu
- College of Liberal Education, Shu-Te University, Kaohsiung County, Tainan, Taiwan, ROC
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30
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Yao L, Dawson PA, Woollett LA. Increases in biliary cholesterol-to-bile acid ratio in pregnant hamsters fed low and high levels of cholesterol. Am J Physiol Gastrointest Liver Physiol 2003; 284:G263-8. [PMID: 12529268 DOI: 10.1152/ajpgi.00332.2002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gallstones develop when the secretion of cholesterol is elevated compared with the secretion of bile acids into bile. One of the risk factors for the formation of gallstones is pregnancy. Because the pregnancy-induced increase in hepatic cholesterol synthesis rates could play a critical role in the development of cholesterol stones, the aim of the present study was to determine whether stone formation, as assessed by the ratio of cholesterol to bile acids in bile, could be ablated by blocking the pregnancy-induced increase in hepatic sterol synthesis rates. Golden Syrian hamsters were fed either ground chow or chow supplemented with 0.5% cholesterol for 3 wk and studied in the nonpregnant state or in late gestation. In chow-fed animals, a 1.6-fold increase in the ratio of cholesterol to bile acids occurred simultaneously with a sevenfold increase in hepatic sterol synthesis rate and a ninefold increase in the amount of newly synthesized cholesterol secreted into the bile in late gestation. In the cholesterol-fed dams, an increase in the ratio of cholesterol to bile acids occurred even with the lack of induction of hepatic sterol synthesis rates during pregnancy. Thus it appears that the marked induction of hepatic sterol synthesis rates during gestation is not essential for the pregnancy-induced cholesterol saturation of bile when cholesterol is fed to animals.
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Affiliation(s)
- Lihang Yao
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45267-0529, USA
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García-Mediavilla V, Villares C, Culebras JM, Báyon JE, González-Gallego J. Effects of dietary beta-cyclodextrin in hypercholesterolaemic rats. PHARMACOLOGY & TOXICOLOGY 2003; 92:94-9. [PMID: 12747579 DOI: 10.1034/j.1600-0773.2003.920206.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Beta-cyclodextrin is a compound that forms inclusion complexes with a variety of molecules, specially bile acids and sterols. This study examines the effects of beta-cyclodextrin on cholesterol and bile acid metabolism in hypercholesterolaemic rats. Male Wistar rats were divided into 4 groups that received during 7 weeks: control diet, 2% cholesterol diet (A), A+2.5% beta-cyclodextrin (B) and A+5% beta-cyclodextrin (C). The cholesterol-rich diet induced hepatomegaly and fatty liver and significantly reduced cholesterol, bile acid and phospholipid secretion. Addition of beta-cyclodextrin normalised biliary lipid secretion. Moreover, when compared to A, beta-cyclodextrin significantly lowered plasma phospholipid concentration (B: -21%; C: -29%) and the liver free/total cholesterol molar ratio (B: -40%; C: -38%), increased bile acid faecal output (B: +17%; C: +62%) and enhanced cholesterol 7alpha-hydroxylase activity (B:+50%; C : +100%)and mRNA levels (B: + 14%; C: +29%). 5% beta-cyclodextrin also reduced plasma triglycerides concentration (-38%). However, ALT and AST activities were significantly increased (B: +140% and +280%; C: +72% and +135%) and there was a high incidence of cell necrosis with portal inflammatory cell infiltration. Addition of beta-cyclodextrin to a cholesterol-rich diet results in a triglyceride-lowering action, enhancement of bile acid synthesis and excretion, and normalization of biliary lipid secretion, but produces a marked hepatotoxic effect.
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Cheema SK, Goel V, Basu TK, Agellon LB. Dietary rhubarb (Rheum rhaponticum) stalk fibre does not lower plasma cholesterol levels in diabetic rats. Br J Nutr 2003; 89:201-6. [PMID: 12575904 DOI: 10.1079/bjn2002768] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rhubarb (Rheum rhapontiam) stalk fibre was previously shown to be hypolipidaemic under clinical and experimental conditions. The present study was undertaken to investigate whether rhubarb stalk fibre has a hypolipidaemic effect under diabetic conditions. Two models of diabetic rats were used: streptozotocin-induced diabetic rats, and diabetes-prone BB (BBdp) rats. The plasma cholesterol and triacylglycerol concentrations were elevated after the onset of diabetes in BBdp rats, but not in sterptozotocin-induced diabetic rats. The rhubarb-fibre diet had no effect on the plasma cholesterol or triacylglycerol concentrations of diabetic rats. The hypolipidaemic effect of rhubarb stalk fibre has been suggested to be due to the bile-acid-binding capacity of rhubarb fibre, which in turn up regulates cholesterol 7alpha-hydroxylase (cyp7a) activity. cyp7a is the first and the rate-limiting enzyme in the breakdown of cholesterol to bile acids. We measured the cyp7a activity and mRNA levels in control and diabetic rats fed rhubarb- and cellulose-fibre diets. The cyp7a activity and mRNA abundance were increased in both diabetic rat models, indicating that bile acid synthesis is enhanced in diabetes. Feeding a diet enriched with rhubarb fibre caused a slight but significant increase (P<0.05) in cyp7a enzyme activity in BBdp rats, but no change in cyp7a mRNA abundance was detected. These results suggest that although a rhubarb-fibre-enriched diet increased cyp7a activity in BBdp rats, there was no apparent therapeutic benefit in terms of lowering plasma cholesterol concentrations.
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Affiliation(s)
- Sukhinder Kaur Cheema
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
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Roy S, Freake HC, Fernandez ML. Gender and hormonal status affect the regulation of hepatic cholesterol 7alpha-hydroxylase activity and mRNA abundance by dietary soluble fiber in the guinea pig. Atherosclerosis 2002; 163:29-37. [PMID: 12048119 DOI: 10.1016/s0021-9150(01)00749-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Dietary soluble fiber (SF) consistently lowers plasma LDL cholesterol (LDL-C) concentrations, however, secondary mechanisms governing this reduction are not completely defined. Moreover, these mechanisms appear to differ with gender. Male, female and ovariectomized (to mimic menopause) guinea pigs were used to assess effects of gender, hormonal status and SF on activity and expression of hepatic cholesterol 7alpha-hydroxylase (CYP7). Diets were identical except for fiber source (control 10% cellulose, SF 5% psyllium/5% pectin). SF intake resulted in 44% lower plasma total cholesterol, 51% lower plasma LDL-C and 22% lower plasma triacylglycerol (TAG) concentrations. However, ovariectomized guinea pigs fed either the control or SF diets, had the highest plasma LDL-C and TAG levels (P<0.01). SF altered hepatic cholesterol metabolism by effectively reducing hepatic free cholesterol, TAG and microsomal free cholesterol, while activity of CYP7, the rate-limiting enzyme of cholesterol catabolism, was up-regulated. Hepatic CYP7 mRNA abundance paralleled the increase in enzyme activity. Ovariectomized guinea pigs had lowest activity and expression of hepatic CYP7 even after intervention with SF. These results suggest that induction of hepatic CYP7 activity may account, in large part, for the hypocholesterolemic effect of SF. Gender and hormonal status influence metabolic responses to dietary SF with estrogen deprivation leading to the most detrimental lipid profile.
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Affiliation(s)
- Suheeta Roy
- Department of Nutritional Sciences, University of Connecticut, 3624 Horsebarn Road Extension, U-17, Storrs, CT 06269, USA
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McCarty MF. Glucomannan minimizes the postprandial insulin surge: a potential adjuvant for hepatothermic therapy. Med Hypotheses 2002; 58:487-90. [PMID: 12323114 DOI: 10.1054/mehy.2001.1457] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Glucomannan (GM) is differentiated from other soluble fibers by the extraordinarily high viscosity of GM solutions. Administration of 4-5g of GM with meals, blended into fluid or mixed with food, can slow carbohydrate absorption and dampen the postprandial insulin response by up to 50%. Controlled clinical studies document that GM can promote satiety and weight loss, lower LDL cholesterol, improve diabetic control, and correct constipation, with minimal if any side-effects. Rodent studies suggest that GM may have potential for decreasing cancer risk and possibly even slowing the ageing process. Hepatothermic therapy, a technique for achieving rapid loss of body fat by optimizing the liver's capacity for fat oxidation, can only achieve its optimal efficacy if diurnal insulin levels are kept low; ingestion of GM with meals will evidently be of benefit in this regard by moderating postprandial insulin surges.
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Romero AL, West KL, Zern T, Fernandez ML. The seeds from Plantago ovata lower plasma lipids by altering hepatic and bile acid metabolism in guinea pigs. J Nutr 2002; 132:1194-8. [PMID: 12042433 DOI: 10.1093/jn/132.6.1194] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Psyllium, the husks from Plantago ovata (PO), is recognized as a potent agent in lowering plasma cholesterol. In this study, we tested the potential hypolipidemic effects of the seeds from PO and the mechanisms associated with the lowering of plasma lipids. Male Hartley guinea pigs (n = 30; 10 per group) were fed either a control diet or diets containing 7.5 or 10 g/100 g PO for 4 wk. Diets were identical in composition except for the fiber source. The control diet contained 10 g/100 g cellulose and 2.5 g/100 g guar gum, whereas the PO diets were adjusted to a total of 12.5 g/100 g fiber with cellulose. Although a dose response was not observed, plasma triglycerides and LDL cholesterol were 34 and 23% lower in the PO groups compared with the control (P < 0.01). Lecithin cholesterol acyltransferase (LCAT) and cholesterol ester transfer protein (CETP) activities were significantly affected by the PO diets. The control group had 100 and 36% higher LCAT and CETP (P < 0.01) activities, respectively, compared with the PO groups. Hepatic total and free cholesterol concentrations were not affected by PO, but cholesteryl ester concentrations were 50% (P < 0.01) lower in the PO groups compared with the control. The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme of cholesterol synthesis was up-regulated in the PO groups by 37%. Similarly, the activity of cholesterol 7alpha-hydroxylase, the regulatory enzyme of cholesterol catabolism to bile acids was 33% higher in the PO groups (P < 0.02). Fecal bile acids were 3 times higher in the PO groups than in the control group. These results suggest that PO exerts its hypolipidemic effect by affecting bile acid absorption and altering hepatic cholesterol metabolism.
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Affiliation(s)
- Ana Lourdes Romero
- Department of Food Science, University of Sonora, Hermosillo, Sonora State, Mexico
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Piyachaturawat P, Srivoraphan P, Chuncharunee A, Komaratat P, Suksamrarn A. Cholesterol lowering effects of a choleretic phloracetophenone in hypercholesterolemic hamsters. Eur J Pharmacol 2002; 439:141-7. [PMID: 11937104 DOI: 10.1016/s0014-2999(02)01453-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The plasma cholesterol-lowering effect and mechanism thereof of a choleretic phloracetophenone or 2,4,6-trihydroxyacetophenone (THA) were investigated in hypercholesterolemic male hamsters. Intragastric administration of THA (300-600 micromol/kg) twice a day for 7 days to these animals caused a dose- and time-dependent decrease in both plasma cholesterol and triglyceride levels. THA at a dose of 400 micromol/kg reduced the cholesterol and triglyceride levels in plasma to 52% and 25% of the level in corresponding cholesterol-fed controls, respectively, with decreases in both plasma very low density lipoprotein and low density lipoprotein cholesterol but not in high density lipoprotein cholesterol. THA did not significantly alter total hepatic cholesterol content but significantly increased the excretion of both bile acids and cholesterol into the intestinal lumen for elimination. Corresponding to the increase in bile acid excretion, THA caused a seven-fold increase in hepatic cholesterol 7alpha-hydroxylase activity. These results suggest that THA exerts its cholesterol lowering effect by increasing hepatic cholesterol 7alpha-hydroxylase activity which increases hepatic conversion of cholesterol to bile acid for disposal via biliary secretion. This compound may have a potential for future development as a therapeutic agent for lowering lipids in hypercholesterolemic patients.
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Affiliation(s)
- Pawinee Piyachaturawat
- Department of Physiology, Faculty of Science, Mahidol University, Rama 6 Road, Rachatewee, Bangkok, 10400, Thailand. scppy @mahidol.ac.th
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Ramjiganesh T, Roy S, Freake HC, McIntyre JC, Fernandez ML. Corn fiber oil lowers plasma cholesterol by altering hepatic cholesterol metabolism and up-regulating LDL receptors in guinea pigs. J Nutr 2002; 132:335-40. [PMID: 11880551 DOI: 10.1093/jn/132.3.335] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To evaluate some of the mechanisms involved in the hypocholesterolemic effects of corn fiber oil (CFO), male Hartley guinea pigs were fed diets containing increasing doses of CFO [0 (control), 5, 10 or 15 g/100 g]. Total fat was adjusted to 15 g/100 g in all diets with regular corn oil. Diets contained 0.25 g/100 g cholesterol. A positive control group (LC) with low dietary cholesterol (0.04 g/100 g) was also included. Plasma LDL cholesterol concentrations were 32, 55 and 57% (P < 0.0005) lower with increasing doses of CFO. Compared with controls, intake of CFO resulted in 27-32% lower hepatic microsomal cholesterol (P < 0.0001), the regulatory pool of LDL receptor (LDL-R) expression. CFO intake resulted in favorable plasma and hepatic cholesterol concentrations, similar to those in guinea pigs fed the LC diet. Hepatic cholesterol 7alpha-hydroxylase (CYP7) activity was approximately 88% higher in guinea pigs fed the two higher dosages of CFO (P < 0.05). In parallel, CYP7 mRNA abundance was approximately 88% higher in guinea pigs fed all three CFO diets. CFO treatment also induced hepatic LDLR mRNA by 66-150% with significant differences at the highest CFO dose. These results suggest that CFO, as a result of decreased bile acid absorption, increased mRNA abundance and activity of CYP7. Because hepatic cholesterol is the substrate for CYP7, a lowering of cholesterol concentrations in the total and microsomal pools was observed. As a response to the depleted microsomal free cholesterol pool, the LDL receptor was up-regulated, drawing more cholesterol from plasma, thus leading to the observed decrease in plasma LDL cholesterol concentrations.
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MESH Headings
- Animals
- Base Sequence
- Cholesterol/blood
- Cholesterol/metabolism
- Cholesterol 7-alpha-Hydroxylase/genetics
- Cholesterol 7-alpha-Hydroxylase/metabolism
- Cholesterol, Dietary/administration & dosage
- Cholesterol, LDL/blood
- Corn Oil/pharmacology
- DNA, Complementary/chemistry
- Dietary Fats, Unsaturated/pharmacology
- Guinea Pigs
- Humans
- Liver/drug effects
- Liver/metabolism
- Microsomes, Liver/drug effects
- Microsomes, Liver/metabolism
- Molecular Sequence Data
- RNA, Messenger/analysis
- Rats
- Receptors, LDL/drug effects
- Receptors, LDL/genetics
- Receptors, LDL/metabolism
- Sequence Homology
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Abstract
The association between elevated plasma LDL-cholesterol concentrations and increased risk for heart disease has made the scientific community aware of dietary sources that might effectively reduce plasma cholesterol levels. Several large-scale cohort studies have documented that dietary fiber lowers the risk for coronary heart disease. In addition, there is substantial evidence from randomized controlled clinical trials that a mean reduction of 9% in LDL-cholesterol can be achieved by intake of different sources of soluble fiber. Incorporating fiber sources into our diet may provide a useful adjunct to a low-saturated fat diet, and may have a further beneficial effect for individuals who have mild-to-moderate hypercholesterolemia. The physicochemical properties of soluble fiber result in important modifications in volume, bulk and viscosity in the intestinal lumen, which will alter metabolic pathways of hepatic cholesterol and lipoprotein metabolism, resulting in lowering of plasma LDL-cholesterol.
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Affiliation(s)
- M L Fernandez
- Department of Nutritional Sciences, The University of Connecticut, Storrs, Connecticut 06269, USA.
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Abstract
Guinea pigs carry the majority of their plasma cholesterol in LDL, making them a unique animal model with which to study hepatic cholesterol and lipoprotein metabolism. In this review, the benefits and advantages of using this particular model are discussed. How dietary factors such as soluble fiber, cholesterol and fatty acids that vary in saturation and chain length affect hepatic cholesterol homeostasis and influence the synthesis, intravascular processing and catabolism of lipoproteins is reviewed. In addition, alterations in hepatic cholesterol metabolism and plasma lipoproteins as affected by treatment with cholestyramine or 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors, exercise, marginal intake of vitamin C, ovariectomy (a model for menopause) and similarities to the human situation are addressed. A review of guinea pigs as models for early atherosclerosis development is also presented.
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Affiliation(s)
- M L Fernandez
- Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut 06269-4017, USA.
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40
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Buhman KK, Furumoto EJ, Donkin SS, Story JA. Dietary psyllium increases expression of ileal apical sodium-dependent bile acid transporter mRNA coordinately with dose-responsive changes in bile acid metabolism in rats. J Nutr 2000; 130:2137-42. [PMID: 10958804 DOI: 10.1093/jn/130.9.2137] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Psyllium (PSY), a type of dietary fiber containing mainly soluble components, has been shown to decrease serum cholesterol concentrations in several species; however, mechanisms involved are not clearly defined. Four groups of 10 rats were fed semipurified diets containing 10% dietary fiber from cellulose and/or PSY for 21 d. Increasing levels of PSY were fed (0,3.33, 6.67 and 10% PSY) with the remaining 10% made up with cellulose. Liver cholesterol, cholesterol 7alpha-hydroxylase (CYP7A) activity and mRNA, 3-hydroxy-3-methylglutaryl CoA reductase (HMGR) mRNA, ileal apical sodium-dependent bile acid transporter (ASBT) mRNA, fecal bile acids and total steroids, and intestinal bile acid content were measured. All variables responded in a dose-dependent manner to PSY in the diet. Total liver cholesterol content was significantly reduced in all groups fed PSY compared to cellulose-fed controls [138(a), 105(b), 105(b) and 93(c) micromol (SEM = 4.2) for 0, 3.33, 6.67 and 10% PSY, respectively]. Activity of CYP7A was significantly greater in all groups fed PSY compared to the cellulose-fed controls [6.36(c), 16.92(b), 15.28(b) and 20.37(a) pmol x min(-1) x mg protein(-1) (SEM = 3.19) for 0, 3.33, 6.67 and 10% PSY, respectively]. These differences in CYP7A activity were similar to differences in CYP7A, HMGR and ASBT mRNA levels. Fecal bile acid and total steroid excretion as well as total intestinal bile acids were significantly greater in rats fed PSY-containing diets compared to 0% PSY-fed rats. These results suggest that the reduction in liver cholesterol involves modulating the size and composition of the bile acid pool via regulation of ileal ASBT, CYP7A and HMGR mRNA levels.
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Affiliation(s)
- K K Buhman
- Departments of. Foods and Nutrition and. Animal Science, Purdue University, West Lafayette, IN 47907, USA
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41
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Anderson JW, Davidson MH, Blonde L, Brown WV, Howard WJ, Ginsberg H, Allgood LD, Weingand KW. Long-term cholesterol-lowering effects of psyllium as an adjunct to diet therapy in the treatment of hypercholesterolemia. Am J Clin Nutr 2000; 71:1433-8. [PMID: 10837282 DOI: 10.1093/ajcn/71.6.1433] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Hypercholesterolemia is a major risk factor for coronary heart disease and nutrition management is the initial therapeutic approach. OBJECTIVE This multicenter study evaluated the long-term effectiveness of psyllium husk fiber as an adjunct to diet in the treatment of persons with primary hypercholesterolemia. DESIGN Men and women with hypercholesterolemia were recruited. After following an American Heart Association Step I diet for 8 wk (dietary adaptation phase), eligible subjects with serum LDL-cholesterol concentrations between 3.36 and 4.91 mmol/L were randomly assigned to receive either 5.1 g psyllium or a cellulose placebo twice daily for 26 wk while continuing diet therapy. RESULTS Serum total and LDL-cholesterol concentrations were 4.7% and 6.7% lower in the psyllium group than in the placebo group after 24-26 wk (P < 0.001). Other outcome measures did not differ significantly between groups. CONCLUSIONS Treatment with 5.1 g psyllium twice daily produces significant net reductions in serum total and LDL-cholesterol concentrations in men and women with primary hypercholesterolemia. Psyllium therapy is an effective adjunct to diet therapy and may provide an alternative to drug therapy for some patients.
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Affiliation(s)
- J W Anderson
- University of Kentucky and the Veterans Affairs Medical Center, Lexington, KY 40511, USA.
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Cordero-MacIntyre ZR, Lohman TG, Rosen J, Peters W, España RC, Dickinson B, Reid PM, Howell WH, Fernandez ML. Weight loss is correlated with an improved lipoprotein profile in obese postmenopausal women. J Am Coll Nutr 2000; 19:275-84. [PMID: 10763910 DOI: 10.1080/07315724.2000.10718927] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight. OBJECTIVE The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity. DESIGN A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30-38 kg/m2) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints. RESULTS Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption. CONCLUSION Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.
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Roy S, Vega-Lopez S, Fernandez ML. Gender and hormonal status affect the hypolipidemic mechanisms of dietary soluble fiber in guinea pigs. J Nutr 2000; 130:600-7. [PMID: 10702591 DOI: 10.1093/jn/130.3.600] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective of this study was to assess the effects of gender on the secondary mechanisms by which dietary soluble fiber lowers plasma LDL cholesterol. For that purpose, male, female and ovariectomized (to mimic menopause) guinea pigs (8-10 per group) were allocated to two dietary treatments. Diets were identical in composition except for the fiber source: the control diet contained 10 g/100 of cellulose and 2.5 g/100 g of guar gum, while the soluble fiber (SF) diet contained 5 g/100 of psyllium, 5 g/100 of pectin and 2.5 g/100 g of guar gum. SF intake resulted in 44% lower plasma LDL cholesterol, 64% lower apo B and 22% lower plasma triacylglycerol (TAG) concentrations (P < 0.01) compared to guinea pigs fed the control diet. However, ovariectomized guinea pigs had higher plasma cholesterol, apo B and TAG concentrations (P < 0.01) compared to males and females, even those fed SF. Plasma HDL-cholesterol was higher in females than in males (P < 0.05). LDL size, as measured by LDL composition and fast protein liquid chromatography, was larger in females than males. Guinea pigs fed SF had smaller LDL than controls. LDL susceptibility to oxidation was 80% lower in male and females fed the SF diet (P < 0.001) than in controls, while there was no effect of diet in ovariectomized guinea pigs. Hepatic free cholesterol and TAG were lower, and activities of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase and cholesterol 7alpha-hydroxylase were higher in guinea pigs fed SF (P < 0.05) than in controls. These results indicate that gender plays an important role in the metabolic responses to dietary soluble fiber and that estrogen deprivation leads to a detrimental lipoprotein profile.
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Affiliation(s)
- S Roy
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
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45
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Abstract
Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.
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Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
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46
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Kuroki S, Naito T, Chijiiwa K, Tanaka M. Effects of cholestyramine on hepatic cholesterol 7alpha-hydroxylase and serum 7alpha-hydroxycholesterol in the hamster. Lipids 1999; 34:817-23. [PMID: 10529092 DOI: 10.1007/s11745-999-0428-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cholestyramine increases activities of hepatic cholesterol 7alpha-hydroxylase and serum levels of 7alpha-hydroxycholesterol. To examine if serum 7alpha-hydroxycholesterol levels parallel with enzyme activity, 0, 0.5, 1, 2, 4, and 10% of cholestyramine was administered to female golden Syrian hamsters for 28 d in the dose-dependent study, and 2% cholestyramine for 0, 1, 3, 7, 14, 21, and 28 d in the time-dependent study. In the dose-dependent study, hepatic and serum cholesterol levels were significantly decreased dose-dependently when more than 0.5% of cholestyramine was fed for 28 d. Cholestyramine increased the cholesterol 7alpha-hydroxylase activity in a dose-dependent manner, while the serum 7alpha-hydroxycholesterol level was essentially unchanged. No correlation was found between the serum level and the hepatic enzyme activity. In the time-dependent study, hepatic and serum cholesterol levels markedly decreased when 2% cholestyramine was fed for longer than 3 d. The serum triglyceride level increased significantly for the first 7 d and then decreased. Cholesterol 7alpha-hydroxylase activity increased significantly as early as day 1, reached maximum activity level on day 7, and then kept the significantly high values until day 28. The serum 7alpha-hydroxycholesterol level significantly increased for the first 7 d and decreased to the pretreatment level thereafter. 7Alpha-hydroxycholesterol levels significantly correlated with serum cholesterol and triglyceride levels. We conclude that the serum 7alpha-hydroxycholesterol level does not always reflect the activity of hepatic cholesterol 7alpha-hydroxylase, when cholesterol metabolism is severely disturbed by cholestyramine.
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Affiliation(s)
- S Kuroki
- Department of Surgery I, Kyushu University Faculty of Medicine, Fukuoka, Japan.
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47
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Spady DK, Kearney DM, Hobbs HH. Polyunsaturated fatty acids up-regulate hepatic scavenger receptor B1 (SR-BI) expression and HDL cholesteryl ester uptake in the hamster. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)33380-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Fernandez ML, Wilson TA, Conde K, Vergara-Jimenez M, Nicolosi RJ. Hamsters and guinea pigs differ in their plasma lipoprotein cholesterol distribution when fed diets varying in animal protein, soluble fiber, or cholesterol content. J Nutr 1999; 129:1323-32. [PMID: 10395594 DOI: 10.1093/jn/129.7.1323] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
There were two objectives to these studies: 1) to compare the lipoprotein cholesterol distribution in two animal models in response to different dietary treatments and 2) to assess whether the hypercholesterolemia induced by high cholesterol intake could be reversed by consumption of vegetable-protein and/or dietary fiber. Guinea pigs, which carry the majority of plasma cholesterol in LDL, and hamsters, with a higher distribution of cholesterol in HDL, were evaluated in three different studies. In Study 1, animals were fed semi-purified diets for 4 wk with proportions of 60:40, 20:80 or 0:100 (w/w) of casein/ soybean protein. Hamsters and guinea pigs that consumed 100% soybean protein had lower plasma total cholesterol (TC) than those fed diets containing casein (P < 0.01). In Study 2, three doses of dietary pectin (2.7, 5.4, or 10.7 g/100g) added in place of cellulose were tested. Intake of 10.7 g/100 g pectin resulted in the lowest plasma TC concentrations for both species (P < 0.01). Although the TC lowering was similar in studies 1 and 2, the lipoprotein cholesterol distribution differed. Whereas the differences in plasma cholesterol were in LDL in guinea pigs, hamsters exhibited differences in both non-HDL and HDL cholesterol. In study 3, animals were fed 100% soybean protein, 10.7 g/100 g pectin, and three doses of dietary cholesterol: 0.04, 0.08, or 0.16 g/100 g, which is equivalent to 300, 600, or 1,200 mg/d in humans. Guinea pigs and hamsters had the highest plasma LDL and hepatic cholesterol concentrations when they consumed 0.16 g/100 g of cholesterol (P < 0.01). However, intake of 0.08 g/100 g of cholesterol resulted in lower plasma LDL cholesterol concentrations than did consuming high animal protein (60:40 casein/ soy) or low soluble fiber (2.7 g/100 g). Relatively high levels of dietary cholesterol combined with vegetable protein and soluble fiber resulted in desirable lipoprotein profiles in animal models that significantly differ in their lipoprotein cholesterol distribution.
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Affiliation(s)
- M L Fernandez
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
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49
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Trautwein EA, Kunath-Rau A, Erbersdobler HF. Increased fecal bile acid excretion and changes in the circulating bile acid pool are involved in the hypocholesterolemic and gallstone-preventive actions of psyllium in hamsters. J Nutr 1999; 129:896-902. [PMID: 10203567 DOI: 10.1093/jn/129.4.896] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The lipid-lowering effect of psyllium (PSY) is well established. Enhanced fecal bile acid excretion and a stimulation of hepatic bile acid synthesis are discussed as primary mechanisms of this action. To further examine the effect of bile acid excretion and specifically of compositional alterations in the bile acid pool on the cholesterol-lowering and gallstone-preventing action of PSY, male golden Syrian hamsters were fed lithogenic diets containing 5 g/100 g fat, 0.4 g/100 g cholesterol and 0 (control), 4 or 6% PSY or 1% cholestyramine (CHY). PSY significantly lowered plasma total cholesterol and triacylglycerol at a magnitude comparable to that induced by CHY. Although hepatic cholesteryl ester accumulation was completely inhibited by CHY, PSY did not prevent the hepatic storage of esterified cholesterol. PSY and CHY caused distinct alterations in the bile acid profile. PSY caused a selective reduction of taurine-conjugated bile acids, especially of taurochenodeoxycholate. As a result, the glycine:taurine conjugation and the cholate:chenodeoxycholate ratios were significantly higher in PSY-fed hamsters. PSY and CHY normalized the lithogenic index and prevented cholesterol gallstone formation compared with controls. Daily fecal bile acid excretion was approximately 400% greater in hamsters fed 6% PSY, whereas CHY caused an 11-fold increase. Daily neutral sterol excretion did not differ in PSY-fed hamsters but was >100% greater in those fed CHY than in controls. These data emphasize the potent lipid-lowering effect of PSY. Increased fecal bile acid excretion and alterations of the circulating bile acid pool by removal of dihydroxy bile acids (e.g., taurochenodeoxycholate) appear to be main modulators of the hypocholesterolemic action of PSY by leading to an up-regulation of hepatic bile acid synthesis.
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Affiliation(s)
- E A Trautwein
- Institute of Human Nutrition and Food Science, University of Kiel, 24105 Kiel, Germany
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50
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Romero AL, Romero JE, Galaviz S, Fernandez ML. Cookies enriched with psyllium or oat bran lower plasma LDL cholesterol in normal and hypercholesterolemic men from Northern Mexico. J Am Coll Nutr 1998; 17:601-8. [PMID: 9853540 DOI: 10.1080/07315724.1998.10718809] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Psyllium and oat bran have been shown to lower plasma LDL cholesterol levels in different populations. Hypercholesterolemia is prevalent in the Northern part of Mexico and might be associated to dietary habits and sedentary lifestyle. METHODS Sedentary normal (cholesterol<200 mg/dL) (n=36) and hypercholesterolemic (cholesterol>220 mg/dL) (n=30) men from the Northern part of Mexico aged 20 to 45 years of age participated in an 8-week study to determine the effects of dietary soluble fiber, either psyllium or oat bran, in lowering plasma LDL cholesterol in this population. Fiber was administered by feeding the subjects an amount of cookies (100 g) equivalent to 1.3 or 2.6 g/day of soluble fiber from psyllium or oat bran, respectively. Subjects were randomly allocated to three groups: a control group consuming cookies with wheat bran, a known source of fiber with no cholesterol lowering effects, psyllium, or oat bran. RESULTS Food frequency questionnaires indicated that subjects from the three groups had similar intakes of foods classified as hypercholesterolemic (p>0.05). Plasma LDL cholesterol concentrations were reduced by an average of 22.6 and 26% in the psyllium and oat bran groups (p<0.001) while a non-significant reduction of 8.4% was observed in the hypercholesterolemic individuals from the control group. No effects on plasma HDL or triglycerides levels were observed among the three dietary treatments except for hypercholesterolemic individuals supplemented with oat bran where a 28% reduction in plasma triglycerides was observed after 8 weeks (p<0.01). CONCLUSION These results indicate that psyllium and oat bran are efficacious in lowering plasma LDL cholesterol in both normal and hypercholesterolemic individuals from this population.
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Affiliation(s)
- A L Romero
- Centro de Investigacion y Postgrado, Universidad de Sonora, Hermosillo, Mexico
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