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Nishikawa M, Ohara N, Naito Y, Saito Y, Amma C, Tatematsu K, Baoyindugurong J, Miyazawa D, Hashimoto Y, Okuyama H. Rapeseed (canola) oil aggravates metabolic syndrome-like conditions in male but not in female stroke-prone spontaneously hypertensive rats (SHRSP). Toxicol Rep 2022; 9:256-268. [PMID: 35242585 PMCID: PMC8866840 DOI: 10.1016/j.toxrep.2022.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 11/30/2021] [Accepted: 01/25/2022] [Indexed: 11/18/2022] Open
Abstract
Canola oil shortens life of male SHRSP. Testis is the target of canola oil toxicity. Inhibition of negative regulation by testosterone of aldosterone production may be a trigger of canola oil toxicity. Facilitation of hypertension by aldosterone may lead to life-shortening. Increased plasma lipids by canola oil have no relevance to life-shortening.
This study was conducted to investigate whether or not there are sex differences in canola oil (CAN)-induced adverse events in the rat and to understand the involvement and the role of testosterone in those events, including life-shortening. Stroke-prone spontaneously hypertensive rats (SHRSP) of both sexes were fed a diet containing 10 wt/wt% soybean oil (SOY, control) or CAN as the sole dietary fat. The survival of the males fed the CAN diet was significantly shorter than that of those fed the SOY diet. In contrast, the survival of the females was not affected by CAN. The males fed the CAN diet showed elevated blood pressure, thrombopenia and insulin-tolerance, which are major symptoms of metabolic syndrome, whereas such changes by the CAN diet were not found in the females. Plasma testosterone was significantly lower in animals of both sexes fed the CAN diet than in those fed the SOY diet, but interestingly, the lowered testosterone was accompanied by a marked increase in plasma aldosterone only in the males. These results demonstrate significant sex differences in CAN-toxicity and suggest that those sex differences may be attributable to the increased aldosterone level, which triggers aggravation of the genetic diseases specific to SHRSP, that is, metabolic syndrome-like conditions, but only in the males. The present results also suggest that testosterone may negatively regulate aldosterone production in the physiology of the males, and the inhibition of that negative regulation caused by the CAN diet is one of the possible causes of the adverse events.
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Affiliation(s)
- Mai Nishikawa
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
| | - Naoki Ohara
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
- Corresponding author.
| | - Yukiko Naito
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Yoshiaki Saito
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Chihiro Amma
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
| | - Kenjiro Tatematsu
- Gifu Pharmaceutical University, 5-6-1 Mitabora, Gifu, Gifu 502-8585, Japan
| | - Jinhua Baoyindugurong
- Inner Mongolia Agricultural University, College of Food Science and Engineering, Zhaowuda Rd. 306, Hohhot, Inner Mongolia 010018, PR China
| | - Daisuke Miyazawa
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
| | - Yoko Hashimoto
- School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
| | - Harumi Okuyama
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
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Fully hydrogenated canola oil extends lifespan in stroke-prone spontaneously hypertensive rats. Lipids Health Dis 2021; 20:102. [PMID: 34511125 PMCID: PMC8436556 DOI: 10.1186/s12944-021-01540-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/31/2021] [Indexed: 11/10/2022] Open
Abstract
Background Canola oil (Can) and several vegetable oils shorten the lifespan of stroke-prone spontaneously hypertensive rats (SHRSP). Although similar lifespan shortening has been reported for partially hydrogenated Can, the efficacy of fully hydrogenated oils on the lifespan remains unknown. The present study aimed to investigate the lifespan of SHRSP fed diets containing 10 % (w/w) of fully hydrogenated Can (FHCO) or other oils. Methods Survival test: Upon weaning, male SHRSP were fed a basal diet for rodents mixed with one of the test oils —i.e., FHCO, Can, lard (Lrd), and palm oil (Plm) throughout the experiment. The animals could freely access the diet and drinking water (water containing 1 % NaCl), and their body weight, food intake, and lifespan were recorded. Biochemical analysis test: Male SHRSP were fed a test diet with either FHCO, Can, or soybean oil (Soy) under the same condition, except to emphasize effects of fat, that no NaCl loading was applied. Soy was used as a fat source in the basal diet and was set the control group. Blood pressures was checked every 2 weeks, and serum fat levels and histological analyses of the brain and kidney were examined after 7 or 12 weeks of feeding. Results During the survival study period, the food consumption of FHCO-fed rats significantly increased (15–20 % w/w) compared with that of rats fed any other oil. However, the body weight gain in the FHCO group was significantly less (10–12 %) than that in the control group at 9–11 weeks old. The FHCO (> 180 days) intervention had the greatest effect on lifespan, followed by the Lrd (115 ± 6 days), Plm (101 ± 2 days), and Can (94 ± 3 days) diets. FHCO remarkably decreased the serum cholesterol level compared with Can and the systolic blood pressure from 12 to 16 weeks of age. In addition, while some rats in the Can group exhibited brain hemorrhaging and renal dysfunction at 16 weeks old, no symptoms were observed in the FHCO group. Conclusion This current study suggests that complete hydrogenation decreases the toxicity of Can and even prolongs the lifespan in SHRSP. Supplementary Information The online version contains supplementary material available at 10.1186/s12944-021-01540-7.
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Antunes MM, Godoy G, Fernandes IDL, Manin LP, Zappielo C, Masi LN, de Oliveira VAB, Visentainer JV, Curi R, Bazotte RB. The Dietary Replacement of Soybean Oil by Canola Oil Does Not Prevent Liver Fatty Acid Accumulation and Liver Inflammation in Mice. Nutrients 2020; 12:E3667. [PMID: 33260679 PMCID: PMC7760057 DOI: 10.3390/nu12123667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/16/2020] [Accepted: 11/22/2020] [Indexed: 12/24/2022] Open
Abstract
A high-carbohydrate diet (HCD) is a well-established experimental model of accelerated liver fatty acid (FA) deposition and inflammation. In this study, we evaluated whether canola oil can prevent these physiopathological changes. We evaluated hepatic FA accumulation and inflammation in mice fed with a HCD (72.1% carbohydrates) and either canola oil (C group) or soybean oil (S group) as a lipid source for 0, 7, 14, 28, or 56 days. Liver FA compositions were analyzed by gas chromatography. The mRNA expression of acetyl-CoA carboxylase 1 (ACC1) was measured as an indicator of lipogenesis. The mRNA expression of F4/80, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10, as mediators of liver inflammation, were also measured. The C group stored less n-6 polyunsaturated FAs (n-6 PUFAs) and had more intense lipid deposition of monounsaturated FAs (MUFAs), n-3 PUFAs, and total FAs. The C group also showed higher ACC1 expression. Moreover, on day 56, the C group showed higher expressions of the inflammatory genes F4/80, TNF-α, IL-1β, and IL-6, as well as the anti-inflammatory IL-10. In conclusion, a diet containing canola oil as a lipid source does not prevent the fatty acid accumulation and inflammation induced by a HCD.
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Affiliation(s)
- Marina Masetto Antunes
- Department of Pharmacology and Therapeutics, State University of Maringá, Maringá 87020-900, Brazil; (M.M.A.); (G.G.)
| | - Guilherme Godoy
- Department of Pharmacology and Therapeutics, State University of Maringá, Maringá 87020-900, Brazil; (M.M.A.); (G.G.)
| | - Ingrid de Lima Fernandes
- Department of Chemistry, State University of Maringá, Maringá 87020-900, Brazil; (I.d.L.F.); (L.P.M.); (C.Z.); (J.V.V.)
| | - Luciana Pelissari Manin
- Department of Chemistry, State University of Maringá, Maringá 87020-900, Brazil; (I.d.L.F.); (L.P.M.); (C.Z.); (J.V.V.)
| | - Caroline Zappielo
- Department of Chemistry, State University of Maringá, Maringá 87020-900, Brazil; (I.d.L.F.); (L.P.M.); (C.Z.); (J.V.V.)
| | - Laureane Nunes Masi
- Interdisciplinary Post-Graduate Program in Health Sciences, Cruzeiro do Sul University, São Paulo 03342-000, Brazil; (L.N.M.); (V.A.B.d.O.); (R.C.)
| | - Vivian Araújo Barbosa de Oliveira
- Interdisciplinary Post-Graduate Program in Health Sciences, Cruzeiro do Sul University, São Paulo 03342-000, Brazil; (L.N.M.); (V.A.B.d.O.); (R.C.)
| | - Jesuí Vergílio Visentainer
- Department of Chemistry, State University of Maringá, Maringá 87020-900, Brazil; (I.d.L.F.); (L.P.M.); (C.Z.); (J.V.V.)
| | - Rui Curi
- Interdisciplinary Post-Graduate Program in Health Sciences, Cruzeiro do Sul University, São Paulo 03342-000, Brazil; (L.N.M.); (V.A.B.d.O.); (R.C.)
| | - Roberto Barbosa Bazotte
- Department of Pharmacology and Therapeutics, State University of Maringá, Maringá 87020-900, Brazil; (M.M.A.); (G.G.)
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Miyazawa D, Ohara N, Yamada K, Yasui Y, Kitamori K, Saito Y, Usumi K, Nagata T, Nonogaki T, Hashimoto Y, Miyashiro Y, Homma S, Okuyama H. Dietary soybean oil, canola oil and partially-hydrogenated soybean oil affect testicular tissue and steroid hormone levels differently in the miniature pig. Food Chem Toxicol 2020; 135:110927. [DOI: 10.1016/j.fct.2019.110927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 11/28/2022]
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Ganesan K, Sukalingam K, Xu B. Impact of consumption and cooking manners of vegetable oils on cardiovascular diseases- A critical review. Trends Food Sci Technol 2018. [DOI: 10.1016/j.tifs.2017.11.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Othman RA, Myrie SB, Mymin D, Merkens LS, Roullet JB, Steiner RD, Jones PJ. Ezetimibe reduces plant sterol accumulation and favorably increases platelet count in sitosterolemia. J Pediatr 2015; 166:125-31. [PMID: 25444527 PMCID: PMC4274192 DOI: 10.1016/j.jpeds.2014.08.069] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 08/04/2014] [Accepted: 08/28/2014] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To assess if ezetimibe (EZE), a sterol-absorption inhibitor, improves platelet (PLT) count and size relative to its effect on plasma plant sterol (PS) in patients with sitosterolemia (STSL). STUDY DESIGN Patients with STSL (5 males, 3 females, 16-56 years of age) receiving EZE intervention as part of their routine care participated in this study. EZE was discontinued for 14 weeks (off) and then resumed for another 14 weeks (on). Hematology variables along with plasma and red blood cells (RBC) PS and total cholesterol (TC) levels were measured at the end of each phase. RESULTS EZE increased PLT count (23% ± 9%) and decreased mean PLT volume (MPV; 10% ± 3%, all P < .05). In patients off EZE, PLT counts inversely correlated (r = -0.96 and r = -0.91, all P < .01) with plasma and RBC PS to TC ratio (PS/TC), and MPV positively correlated (r = 0.91, P = .03 and r = 0.93, P = .02) with plasma and RBC PS/TC. EZE reduced plasma and RBC sitosterol (-35% ± 4% and -28% ± 3%), total PS (-37% ± 4% and -28% ± 3%, all P < .0001) levels, and PS/TC (-27% ± 4% and -28% ± 4%, P < .01). CONCLUSIONS EZE reduces plasma and RBC PS levels, while increasing PLT count and decreasing MPV, and thereby may reduce the risk for bleeding in STSL. Plasma PS levels and ABCG5/ABCG8 genes should be analyzed in patients with unexplained hematologic abnormalities.
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Affiliation(s)
- Rgia A. Othman
- Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5,Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5
| | - Semone B. Myrie
- Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5,Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5
| | - David Mymin
- Internal Medicine, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5
| | - Louise S. Merkens
- Pediatrics, Institute on Development and Disability/Doernbecher Children’s Hospital, Oregon Health & Science University, 3181 SW Jackson Park Road, Portland, OR 97239
| | - Jean-Baptiste Roullet
- Pediatrics, Institute on Development and Disability/Doernbecher Children’s Hospital, Oregon Health & Science University, 3181 SW Jackson Park Road, Portland, OR 97239
| | - Robert D. Steiner
- Pediatrics, Institute on Development and Disability/Doernbecher Children’s Hospital, Oregon Health & Science University, 3181 SW Jackson Park Road, Portland, OR 97239,Molecular and Medical Genetics, Institute on Development and Disability/Doernbecher Children’s Hospital, Oregon Health & Science University, 3181 SW Jackson Park Road, Portland, OR 97239,Marshfield Clinic Research Foundation, Marshfield, WI and the University of Wisconsin, Madison, WI
| | - Peter J.H. Jones
- Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5,Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, Canada, R3T 6C5
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Cai J, Jang JY, Kim J, Shin K, Kim KS, Park D, Kim TS, Lee SP, Ahn B, Choi EK, Lee J, Kim YB. Comparative effects of plant oils on the cerebral hemorrhage in stroke-prone spontaneously hypertensive rats. Nutr Neurosci 2014; 19:318-26. [PMID: 24856006 DOI: 10.1179/1476830514y.0000000132] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Since oils and fats can induce metabolic syndrome, leading to cardiovascular and cerebrovascular diseases, the present study was performed to find out whether the plant oils affect the cerebral hemorrhage in stroke-prone spontaneously hypertensive (SHR-SP) rats. METHODS From 47 days of age, male SHR-SP rats were given drinking water containing 1% NaCl to induce hypertension, and simultaneously fed semi-purified diets containing 10% perilla oil, canola oil, or shortening. The onset time of convulsion following cerebral hemorrhage was recorded, and the areas of hemorrhage and infarction were analyzed in the stroke brains. RESULTS In comparison with 58-day survival of SHR-SP rats during feeding NaCl alone, perilla oil extended the survival time to 68.5 days, whereas canola oil shortened it to 45.7 days. Feeding perilla oil greatly reduced the total volume of cerebral hemorrhage from 17.27% in the control group to 4.53%, while shortening increased the lesions to 21.23%. In a microscopic analysis, perilla oil also markedly decreased the hemorrhagic and infarction lesions to 1/10 of those in control rats, in contrast to an exacerbating effect of shortening. In blood analyses, perilla oil reduced blood total cholesterol and low-density lipoproteins which were increased in SHR-SP, but canola oil further increased them and markedly lowered platelet counts. DISCUSSION Perilla oil delayed and attenuated cerebral hemorrhage by improving hyperlipidemia in hypertensive stroke animals, in contrast to the aggravating potential of canola oil and shortening. It is suggested that perilla oil should be the first choice oil for improving metabolic syndrome in hypertensive persons at risk of hemorrhagic stroke.
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Affiliation(s)
- Jingmei Cai
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Ja-Young Jang
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Jihyun Kim
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Kyungha Shin
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Kwang Sei Kim
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Dongsun Park
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | | | | | - Byeongwoo Ahn
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Ehn-Kyoung Choi
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
| | - Junsoo Lee
- c Department of Food Science and Technology , Chungbuk National University , Cheongju , Korea
| | - Yun-Bae Kim
- a College of Veterinary Medicine, Chungbuk National University , Cheongju , Korea
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Papazzo A, Conlan XA, Lexis L, Charchar FJ, Lewandowski PA. Salt loading in canola oil fed SHRSP rats induces endothelial dysfunction. PLoS One 2013; 8:e66655. [PMID: 23762494 PMCID: PMC3676377 DOI: 10.1371/journal.pone.0066655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 05/13/2013] [Indexed: 01/17/2023] Open
Abstract
This study aimed to determine if 50 days of canola oil intake in the absence or presence of salt
loading affects: (1) antioxidant and oxidative stress markers, (2) aortic mRNA of NADPH oxidase (NOX) subunits and superoxide dismutase (SOD) isoforms and (3) endothelial function in SHRSP rats. SHRSP rats were fed a diet containing 10 wt/wt% soybean oil or 10 wt/wt% canola oil, and given tap water or water containing 1% NaCl for 50 days. Without salt, canola oil significantly increased RBC SOD, plasma cholesterol and triglycerides, aortic p22phox, NOX2 and CuZn-SOD mRNA, and decreased RBC glutathione peroxidase activity. With salt, canola oil reduced RBC SOD and catalase activity, LDL-C, and p22phox mRNA compared with canola oil alone, whereas plasma malondialdehyde (MDA) was reduced and RBC MDA and LDL-C were higher. With salt, the canola oil group had significantly reduced endothelium-dependent vasodilating responses to ACh and contractile responses to norepinephrine compared with the canola oil group without salt and to the WKY rats. These results indicate that ingestion of canola oil increases O2− generation, and that canola oil ingestion in combination with salt leads to endothelial dysfunction in the SHRSP model.
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Affiliation(s)
| | - Xavier A. Conlan
- Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Victoria, Australia
| | - Louise Lexis
- Department of Human Biosciences, La Trobe University, Victoria, Australia
| | - Fadi J. Charchar
- School of Health Sciences, University of Ballarat, Ballarat, Australia
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Hoekstra J, Fransen HP, van Eijkeren JC, Verkaik-Kloosterman J, de Jong N, Owen H, Kennedy M, Verhagen H, Hart A. Benefit–risk assessment of plant sterols in margarine: A QALIBRA case study. Food Chem Toxicol 2013; 54:35-42. [DOI: 10.1016/j.fct.2012.08.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 08/06/2012] [Accepted: 08/07/2012] [Indexed: 11/17/2022]
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Papazzo A, Conlan X, Lexis L, Lewandowski P. The effect of short-term canola oil ingestion on oxidative stress in the vasculature of stroke-prone spontaneously hypertensive rats. Lipids Health Dis 2011; 10:180. [PMID: 21999921 PMCID: PMC3215974 DOI: 10.1186/1476-511x-10-180] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 10/17/2011] [Indexed: 02/07/2023] Open
Abstract
Background This study aimed to determine if 25 days of canola oil intake in the absence of excess dietary salt or together with salt loading affects antioxidant and oxidative stress markers in the circulation. A further aim was to determine the mRNA expression of NADPH oxidase subunits and superoxide dismutase (SOD) isoforms in the aorta of stroke-prone spontaneously hypertensive (SHRSP) rats. Methods Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given tap water or water containing 1% NaCl. Blood was collected at the end of study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8-isoprostane and plasma lipids. The aorta was removed and the mRNA expression of NOX2, p22phox, CuZn-SOD, Mn-SOD and EC-SOD were determined. Results In the absence of salt, canola oil reduced RBC SOD and glutathione peroxidase, and increased total cholesterol and LDL cholesterol compared with soybean oil. RBC glutathione peroxidase activity was significantly lower in both the salt loaded groups compared to the soybean oil only group. In addition, RBC MDA and plasma HDL cholesterol were significantly higher in both the salt loaded groups compared to the no salt groups. Plasma MDA concentration was higher and LDL cholesterol concentration lower in the canola oil group loaded with salt compared to the canola oil group without salt. The mRNA expression of NADPH oxidase subunits and SOD isoforms were significantly reduced in the canola oil group with salt compared to canola oil group without salt. Conclusion In conclusion, these results indicate that canola oil reduces antioxidant status and increases plasma lipids, which are risk factors for cardiovascular disease. However, canola oil in combination with salt intake increased MDA, a marker of lipid peroxidation and decreased NAPDH oxidase subunits and aortic SOD gene expression.
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Papazzo A, Conlan XA, Lexis L, Lewandowski PA. Differential effects of dietary canola and soybean oil intake on oxidative stress in stroke-prone spontaneously hypertensive rats. Lipids Health Dis 2011; 10:98. [PMID: 21669000 PMCID: PMC3126710 DOI: 10.1186/1476-511x-10-98] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 06/13/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Canola oil shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats compared with rats fed soybean oil when given as the sole dietary lipid source. One possible mechanism leading to the damage and deterioration of organs due to canola oil ingestion is oxidative stress. This study investigated the effect of canola oil intake on oxidative stress in this animal model. METHOD Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given water containing 1% NaCl. Blood pressure was measured weekly. Blood was collected prior to beginning the diets and at the end of completion of the study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8-isoprostane and plasma lipids. RESULTS Canola oil ingestion significantly decreased the life span of SHRSP rats compared with soybean oil, 85.8 ± 1.1 and 98.3 ± 3.4 days, respectively. Systolic blood pressure increased over time with a significant difference between the diets at the 6th week of feeding. Canola oil ingestion significantly reduced RBC superoxide dismutase, glutathione peroxidase and catalase activities, total cholesterol and low-density lipoprotein cholesterol compared with soybean oil. There were no significant differences in RBC MDA concentration between canola oil fed and soybean oil fed rats. In contrast, plasma MDA and 8-isoprostane concentration was significantly lower in the canola oil group compared to the soybean oil group. CONCLUSION In conclusion, canola oil ingestion shortens the life span of SHRSP rats and leads to changes in oxidative status, despite an improvement in the plasma lipids.
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Phytosterol supplementation reduces metabolic activity and slows cell growth in cultured rat cardiomyocytes. Br J Nutr 2011; 106:540-8. [PMID: 21554812 DOI: 10.1017/s0007114511000626] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Besides being cholesterol-lowering agents, phytosterols (PS) can inhibit the growth and development of tumours. The anti-neoplastic activity is accounted for by PS incorporation into cell membranes, resulting in the interference of membrane functionality. The similarity between the PS cholesterol-lowering and anti-neoplastic effective doses deserves attention on the possible adverse effects even in non-neoplastic cells. To date, few studies have addressed the clarification of this important issue. In the present study, we supplemented primary, non-neoplastic neonatal rat cardiomyocytes with two different PS concentrations (3 or 6 μg/ml), both within the range of human plasma concentration. Cardiac cells were chosen as an experimental model since the heart has been reported as the target organ for subchronic toxicity of PS. Following supplementation, a dose-dependent incorporation of PS and a decrease in cholesterol content were clearly evidenced. PS did not induce apoptosis but caused a reduction in metabolic activity (measured as 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) conversion) and a slowing down of cell growth. The lower MTT conversion and the similar lactate dehydrogenase release could suggest that PS more efficiently target mitochondria than plasma membrane integrity. The replacement of cholesterol by PS could also have caused the observed slowing down of cell growth and the reduction in metabolic activity, which could rely on the PS increase, cholesterol decrease, or both. The present study is the first report on the effect of PS in cardiac cells, and although it is difficult to translate the obtained results to the health of heart tissue, it raises concerns about the safety of long-term exposure to physiologically relevant PS concentrations.
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Hypertension induced by omega-3 polyunsaturated fatty acid deficiency is alleviated by alpha-linolenic acid regardless of dietary source. Hypertens Res 2010; 33:808-13. [PMID: 20520615 DOI: 10.1038/hr.2010.84] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Omega-3 polyunsaturated fatty acid deficiency, particularly during the prenatal period, can cause hypertension in later life. This study examined the effect of different sources of alpha-linolenic acid (canola oil or flaxseed oil) in the prevention of hypertension and other metabolic symptoms induced by an omega-3 fatty acid-deficient diet. Dams were provided one of three experimental diets from 1 week before mating. Diets were either deficient (10% safflower oil-DEF) or sufficient (7% safflower oil+3% flaxseed oil-SUF-F; or 10% canola oil-SUF-C) in omega-3 fatty acids. The male offspring were continued on the maternal diet from weaning for the duration of the study. Body weight, ingestive behaviors, blood pressure, body composition, metabolic rate, plasma leptin and brain fatty acids were all assessed. The DEF animals were hypertensive at 24 weeks of age compared with SUF-F or SUF-C animals; this was not evident at 12 weeks. These results suggest that different sources of ALA are effective in preventing hypertension related to omega-3 fatty acid deficiency. However, there were other marked differences between the DEF and, in particular, the SUF-C phenotype including lowered body weight, adiposity, leptin and food intake in SUF-C animals. SUF-F animals also had lower, but less marked reductions in adiposity and leptin compared with DEF animals. The differences observed between DEF, SUF-F and SUF-C phenotypes indicate that body fat and leptin may be involved in omega-3 fatty acid deficiency hypertension.
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Chen Q, Gruber H, Swist E, Coville K, Pakenham C, Ratnayake WM, Scoggan KA. Dietary phytosterols and phytostanols decrease cholesterol levels but increase blood pressure in WKY inbred rats in the absence of salt-loading. Nutr Metab (Lond) 2010; 7:11. [PMID: 20637058 PMCID: PMC2843689 DOI: 10.1186/1743-7075-7-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/12/2010] [Indexed: 12/04/2022] Open
Abstract
Background There are safety concerns regarding widespread consumption of phytosterol and phytostanol supplemented food products. The aim of this study was to determine, in the absence of excess dietary salt, the individual effects of excess accumulation of dietary phytosterols and phytostanols on blood pressure in Wistar Kyoto (WKY) inbred rats that have a mutation in the Abcg5 gene and thus over absorb phytosterols and phytostanols. Methods Thirty 35-day old male WKY inbred rats (10/group) were fed a control diet or a diet containing phytosterols or phytostanols (2.0 g/kg diet) for 5 weeks. The sterol composition of the diets, plasma and tissues were analysed by gas chromatography. Blood pressure was measured by the tail cuff method. mRNA levels of several renal blood pressure regulatory genes were measured by real-time quantitative PCR. Results Compared to the control diet, the phytosterol diet resulted in 3- to 4-fold increases in the levels of phytosterols in plasma, red blood cells, liver, aorta and kidney of WKY inbred rats (P < 0.05). The phytostanol diet dramatically increased (> 9-fold) the levels of phytostanols in plasma, red blood cells, liver, aorta and kidney of these rats (P < 0.05). The phytosterol diet decreased cholesterol levels by 40%, 31%, and 19% in liver, aorta and kidney, respectively (P < 0.05). The phytostanol diet decreased cholesterol levels by 15%, 16%, 20% and 14% in plasma, liver, aorta and kidney, respectively (P < 0.05). The phytostanol diet also decreased phytosterol levels by 29% to 54% in plasma and tissues (P < 0.05). Both the phytosterol and phytostanol diets produced significant decreases in the ratios of cholesterol to phytosterols and phytostanols in plasma, red blood cells, liver, aorta and kidney. Rats that consumed the phytosterol or phytostanol diets displayed significant increases in systolic and diastolic blood pressure compared to rats that consumed the control diet (P < 0.05). The phytosterol diet increased renal angiotensinogen mRNA levels of these rats. Conclusion These data suggest that excessive accumulation of dietary phytosterols and phytostanols in plasma and tissues may contribute to the increased blood pressure in WKY inbred rats in the absence of excess dietary salt. Therefore, even though phytosterols and phytostanols lower cholesterol levels, prospective clinical studies testing the net beneficial effects of dietary phytosterols and phytostanols on cardiovascular events for subgroups of individuals that have an increased incorporation of these substances are needed.
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Affiliation(s)
- Qixuan Chen
- Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Banting Research Centre, Ottawa, Ontario K1A 0K9, Canada.
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Ohara N, Naito Y, Kasama K, Shindo T, Yoshida H, Nagata T, Okuyama H. Similar changes in clinical and pathological parameters in Wistar Kyoto rats after a 13-week dietary intake of canola oil or a fatty acid composition-based interesterified canola oil mimic. Food Chem Toxicol 2009; 47:157-62. [DOI: 10.1016/j.fct.2008.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 09/27/2008] [Accepted: 10/26/2008] [Indexed: 11/26/2022]
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16
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Influence of dietary phytosterols and phytostanols on diastolic blood pressure and the expression of blood pressure regulatory genes in SHRSP and WKY inbred rats. Br J Nutr 2008; 102:93-101. [DOI: 10.1017/s0007114508137904] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The aim of the present study was to determine the impact of increased consumption of phytosterols or phytostanols on blood pressure and renal blood pressure regulatory gene expression in stroke-prone spontaneously hypertensive (SHRSP) and normotensive Wistar–Kyoto (WKY) inbred rats. SHRSP and WKY inbred rats (10/group) were fed a control diet or a diet supplemented with phytosterols or phytostanols (2·0 g/kg diet). After 5 weeks, SHRSP rats demonstrated higher systolic and diastolic blood pressures than WKY inbred rats. SHRSP rats that consumed the phytosterol or phytostanol supplemental diets displayed a 2- or 3-fold respective increase in the diastolic blood pressure than those that consumed the control diet. Angiotensinogen (Agt), angiotensin I-converting enzyme 1 (Ace1), nitric oxide synthase (Nos) 1,Nos3, cyclooxygenase 2 (Cox2) and THUMP domain containing 1 were expressed at higher levels in SHRSP compared with WKY inbred rats.Reninand angiotensin II receptor type 1a were expressed at lower levels in SHRSP than WKY inbred rats. Phytostanol supplementation up-regulated the expression ofAce1andNos3in SHRSP rats. Phytosterol supplementation increased the mRNA levels ofNos1and spondin 1 (Spon1) in SHRSP and WKY inbred rats.Cox2mRNA levels were elevated in both phytosterol- and phytostanol-supplemented SHRSP and WKY inbred rats. Therefore, the increased blood pressure in SHRSP rats may be partly due to altered renal expression of blood pressure regulatory genes. Specifically, up-regulation ofAce1,Nos1,Nos3,Cox2andSpon1were associated with the increased diastolic blood pressure observed in phytosterol- or phytostanol-supplemented SHRSP rats.
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de Jong N, Ros MM, Ocké MC, Verhagen H. A general postlaunch monitoring framework for functional foods tested with the phytosterol/-stanol case. Trends Food Sci Technol 2008. [DOI: 10.1016/j.tifs.2008.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ohara N, Kasama K, Naito Y, Nagata T, Saito Y, Kuwagata M, Okuyama H. Different effects of 26-week dietary intake of rapeseed oil and soybean oil on plasma lipid levels, glucose-6-phosphate dehydrogenase activity and cyclooxygenase-2 expression in spontaneously hypertensive rats. Food Chem Toxicol 2008; 46:2573-9. [PMID: 18508177 DOI: 10.1016/j.fct.2008.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 04/02/2008] [Accepted: 04/11/2008] [Indexed: 10/22/2022]
Abstract
We intended to determine whether or not dietary canola oil (CO) elevates plasma lipids and oxidative stress, since both of these are, possibly, related to the CO-induced life shortening through exacerbation of hypertension-associated vascular lesions found in stroke-prone spontaneously hypertensive rats (SHRSP). Spontaneously hypertensive rats (SHR) were used in this study to avoid a potential bias in the results due to the irregular death by stroke seen in SHRSP. SHR were fed for 26 weeks on a chow containing either, 10 wt/wt% of CO or soybean oil (SO), i.e., the control. Elevated plasma lipids and glucose-6-phosphate dehydrogenase (G6PD) activation in the liver and erythrocyte were found in SHR fed CO compared to that fed SO, while anti-oxidative enzymes other than G6PD were not activated. The CO diet brought about significant vascular lesions in the kidney, in which abundant cyclooxygenase-2 (COX-2) positive foci were immunochemically located in the juxtaglomerular apparatus. These results suggest that dietary CO induces a hyperlipidemic condition, in which G6PD may serve as an NADPH provider, and aggravates genetic diseases in SHR (also, probably, in SHRSP). The increased COX-2 expression indicates a role of renin-angiotensin-aldosterone system activation in the increased vascular lesions, whereas the effects of oxidative stress remain unclear.
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Affiliation(s)
- Naoki Ohara
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center, Ochiai 729-5, Hadano, Kanagawa 257-8523, Japan.
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Ohara N, Naito Y, Nagata T, Tachibana S, Okimoto M, Okuyama H. Dietary intake of rapeseed oil as the sole fat nutrient in wistar rats - Lack of increase in plasma lipids and renal lesions -. J Toxicol Sci 2008; 33:641-5. [DOI: 10.2131/jts.33.641] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Naoki Ohara
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center
- Open Research Center for Lipid Nutrition and Gender Specificity, Kinjo Gakuin University
| | - Yukiko Naito
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center
| | - Tomoko Nagata
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center
| | - Shigehiro Tachibana
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center
| | - Mari Okimoto
- Division of Toxicology, Hatano Research Institute, Food and Drug Safety Center
| | - Harumi Okuyama
- Laboratory of Preventive Nutraceutical Sciences, Kinjo Gakuin University College of Pharmacy
- Open Research Center for Lipid Nutrition and Gender Specificity, Kinjo Gakuin University
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Kim BH, Sandock KD, Robertson TP, Lewis SJ, Akoh CC. Dietary Effects of Structured Lipids and Phytosteryl Esters on Cardiovascular Function in Spontaneously Hypertensive Rats. J Cardiovasc Pharmacol 2007; 50:176-86. [PMID: 17703134 DOI: 10.1097/fjc.0b013e31805d8f03] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study examined the dietary effects of sesame oil (SO)-based structured lipids (SL) and phytosteryl esters (PE) on cardiovascular function in conscious spontaneously hypertensive rats (SHR) fed high-fat (HF) diets (20% w/w fat). The dietary groups were as follows: normal diet (4.5% w/w fat), SO, SO fortified with PE (SOP), SL, and SL fortified with PE (SLP). Mean arterial blood pressures were similar in all groups, whereas resting heart rates (HR) were higher in all HF-fed groups. The pressor responses to the alpha1-adrenoceptor agonist, phenylephrine (5 microg/kg), were similar in all groups. However, the pressor responses to phenylephrine (10 microg/kg) were diminished in SO- or SL-fed SHR, whereas they were not diminished in SOP- or SLP-fed SHR. The depressor responses elicited by the nitric oxide (NO) donor, sodium nitroprusside (5 and 10 microg/kg), were not diminished in HF-fed rats. Baroreflex-mediated changes in HR were variously decreased in the HF-fed groups, and this decrease tended to be greater in SOP and SLP than in SO and SL groups. The depressor and tachycardic responses elicited by the beta-adrenoceptor agonist, isoproterenol, were equivalent in all groups. The depressor responses elicited by the endothelium-dependent agonist, acetylcholine (0.1 microg/kg), and the hypertension elicited by the NO synthesis inhibitor, NG-nitro-L-arginine methylester (25 micromol/kg), were similar in all groups. These findings demonstrate that (1) HF diets increase resting HR and impair baroreflex function in SHR, whereas they do not obviously affect endothelium-dependent vasodilation, and (2) fortification with PE may be deleterious to cardiovascular function (eg, baroreflex activity) in SHR.
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Affiliation(s)
- Byung Hee Kim
- Department of Food Science and Technology, University of Georgia, Athens, Georgia 30602-7610, USA
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Alonso A, Ruiz-Gutierrez V, Martínez-González MA. Monounsaturated fatty acids, olive oil and blood pressure: epidemiological, clinical and experimental evidence. Public Health Nutr 2007; 9:251-7. [PMID: 16571180 DOI: 10.1079/phn2005836] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AbstractDiet has an important role in the prevention and treatment of hypertension. In early epidemiological studies, conducted mainly in the USA, monounsaturated fatty acids showed a deleterious association with blood pressure or no relationship at all. However, more recent studies, conducted in Mediterranean countries, have shed new light on this issue. In the present review we summarise the main results of epidemiological studies and feeding trials, and explain the possible mechanisms through which monounsaturated fatty acids, and specifically olive oil as the major dietary source of this type of fat in Mediterranean countries, could exert a favourable effect on blood pressure.
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Affiliation(s)
- Alvaro Alonso
- Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, Irunlarrea 1, ES-31008 Pamplona, Spain
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de Jong A, Plat J, Mensink RP. Plant sterol or stanol consumption does not affect erythrocyte osmotic fragility in patients on statin treatment. Eur J Clin Nutr 2006; 60:985-90. [PMID: 16482072 DOI: 10.1038/sj.ejcn.1602409] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To assess the effects of plant sterol or stanol ester consumption on their incorporation into erythrocytes and their effects on osmotic fragility of red blood cells. DESIGN Double-blind, randomized, placebo-controlled intervention trial. SUBJECTS AND INTERVENTION Forty-one subjects on stable statin treatment - who already have increased serum plant sterol and stanol concentrations - first received for 4 weeks a control margarine. For the next 16 weeks, subjects were randomly assigned to one of three possible interventions. Eleven subjects continued with control margarine, 15 subjects with plant sterol ester enriched and 15 subjects with plant stanol ester-enriched margarine. Daily plant sterol or stanol intake was 2.5 g. Erythrocyte haemolysis was measured spectrophotometrically at five different saline concentrations. RESULTS Despite significant (P = 0.004) increases of, respectively, 42 and 59% in cholesterol-standardized serum sitosterol and campesterol concentrations in the plant sterol group as compared to the control group, campesterol levels in the red blood cells did not change (P = 0.196). Osmotic fragility did not change significantly (P = 0.757) in the plant sterol and plant stanol groups as compared to the control group. CONCLUSION We conclude that plant sterol and stanol ester consumption for 16 weeks does not change osmotic fragility of erythrocytes in statin-treated patients. SPONSORSHIP Netherlands Organisation for Health Research and Development (Program Nutrition: Health, Safety and Sustainability, Grant 014-12-010).
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Affiliation(s)
- A de Jong
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands.
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Ohara N, Naito Y, Nagata T, Tatematsu K, Fuma SY, Tachibana S, Okuyama H. Exploration for unknown substances in rapeseed oil that shorten survival time of stroke-prone spontaneously hypertensive rats. Effects of super critical gas extraction fractions. Food Chem Toxicol 2005; 44:952-63. [PMID: 16364530 DOI: 10.1016/j.fct.2005.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Revised: 09/08/2005] [Accepted: 11/04/2005] [Indexed: 11/21/2022]
Abstract
To identify the causative substances for the shortening of survival time by rapeseed (Canola) oil in stroke-prone spontaneously hypertensive rats (SHRSP), SHRSP were fed on a standard chow supplemented with 10 w/w% soybean oil (control), rapeseed oil, one of the fractions of rapeseed oil obtained by super critical gas extraction (SCE) under a pressure of 180-bar or 350-bar, at 40 degrees C, or the residue from the extraction (with 0.5% NaCl in drinking water). In another series of experiment, SHRSP were fed for 8 weeks on the above-mentioned diets without salt loading and autopsied. Fatty acid compositions in these diets were similar, except in the soybean oil diet, and phytosterol contents were: (diet containing) 180-bar fraction>residue>rapeseed oil>350-bar fraction>soybean oil. Survival times in the rapeseed oil, 350-bar fraction and residue groups were shorter than, whereas that in the 180-bar fraction was similar to in the soybean oil group. In the 8-week feeding experiment, chronic nephropathy was found frequently in the groups other than the soybean oil group. The heart weights were higher in the rapeseed oil and residue groups. Cerebral necrosis was found in the residue group. Taken together, the followings are concluded, (1) Neither the fatty acid composition, nor the amount of phytosterols in the diets appeared to be decisive in the shortening of life. (2) SCE appeared to produce a safe (180-bar) fraction, though it failed to separate clearly the causative substances into specific fractions. (3) The factors that facilitate the genetic disease of SHRSP appear to exist in rapeseed oil. However, they might not be identical to those responsible for the life-shortening, since there were no findings common across the rapeseed oil, 350-bar and residue groups, which showed similar life-shortening.
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Affiliation(s)
- Naoki Ohara
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan.
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Tatematsu K, Fuma SY, Nagase T, Ichikawa Y, Fujii Y, Okuyama H. Factors other than phytosterols in some vegetable oils affect the survival of SHRSP rats. Food Chem Toxicol 2004; 42:1443-51. [PMID: 15234074 DOI: 10.1016/j.fct.2004.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Accepted: 04/12/2004] [Indexed: 11/22/2022]
Abstract
Unusual survival-shortening activities of some vegetable oils were detected in stroke-prone spontaneously hypertensive (SHRSP) rats, and phytosterol (PS) in the oils and the tissue tocopherol status have been suggested to be the factors for the activities. Here, we re-evaluated the contribution of PS to the survival-shortening, and examined the hepatic tocopherol status. A basal diet for rodents and a test oil were mixed at a 9:1 ratio, and the diet was given to male SHRSP rats upon weaning. The total and major PS contents of the diets and tissue lipids did not correlate with relative survival time. The free fatty acid fractions obtained by lipase and alkaline hydrolyses of canola oil (Can) and the original Can contained PS in comparable amounts but the free fatty acid fractions did not exhibit survival-shortening activities compared with the soybean oil (Soy) group. The activity was not detected in the ethyl acetate extracts of the aqueous phase after the hydrolysis. When a commercially available PS preparation was added to the Soy diet at an amount 2.8-fold higher than that in the Can diet, the mean survival time was shortened but was still significantly longer than that of the Can group. The hepatic tocopherol level was significantly higher in the Can group than in the hydrogenated Soy group and Soy group, but the former two groups exhibited a survival-shortening activity. These results indicate that factors other than PS, tocopherol status and fatty acid composition in some vegetable oils are critical for the survival-shortening activity observed in SHRSP rats.
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Affiliation(s)
- Kenjiro Tatematsu
- Department of Preventive Nutraceutical Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori, Mizuhoku, Nagoya 467-8603, Japan
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Ratnayake WMN, Plouffe L, L'Abbé MR, Trick K, Mueller R, Hayward S. Comparative health effects of margarines fortified with plant sterols and stanols on a rat model for hemorrhagic stroke. Lipids 2003; 38:1237-47. [PMID: 14870926 DOI: 10.1007/s11745-003-1184-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
There is increased acceptance of fortifying habitual foods with plant sterols and their saturated derivatives, stanols, at levels that are considered safe. These sterols and stanols are recognized as potentially effective dietary components for lowering plasma total and LDL cholesterol. Our previous studies have shown that daily consumption of plant sterols promotes strokes and shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats. These studies question the safety of plant sterol additives. The present study was performed to determine whether a large intake of plant stanols would cause nutritional effects similar to those seen with plant sterols in SHRSP rats. Young SHRSP rats (aged 26-29 d) were fed semipurified diets containing commercial margarines fortified with either plant stanols (1.1 g/100 g diet) or plant sterols (1.4 g/100 g diet). A reference group of SHRSP rats was fed a soybean oil diet (0.02 g plant sterols/100 g diet and no plant stanols). Compared to soybean oil, both plant stanol and plant sterol margarines significantly (P < 0.05) reduced the life span of SHRSP rats. At the initial stages of feeding, there was no difference in the survival rates between the two margarine groups, but after approximately 50 d of feeding, the plant stanol group had a slightly, but significantly (P < 0.05), lower survival rate. Blood and tissue (plasma, red blood cells, liver, and kidney) concentrations of plant sterols in the plant sterol margarine group were three to four times higher than the corresponding tissue concentrations of plant stanols in the plant stanol group. The deformability of red blood cells and the platelet count of SHRSP rats fed the plant sterol margarine were significantly (P < 0.05) lower than those of the plant stanol margarine and soybean oil groups at the end of the study. These parameters did not differ between the soybean oil and plant stanol margarine groups. These results suggest that, at the levels tested in the present study, plant stanols provoke hemorrhagic stroke in SHRSP rats to a slightly greater extent than plant sterols. The results also suggest that the mechanism by which plant stanols shorten the life span of SHRSP rats might differ from that of plant sterols.
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Affiliation(s)
- W M N Ratnayake
- Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada K1A 0L2.
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