1
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Semova I, Levenson AE, Krawczyk J, Bullock K, Gearing ME, Ling AV, Williams KA, Miao J, Adamson SS, Shin DJ, Chahar S, Graham MJ, Crooke RM, Hagey LR, Vicent D, de Ferranti SD, Kidambi S, Clish CB, Biddinger SB. Insulin Prevents Hypercholesterolemia by Suppressing 12a-Hydroxylated Bile Acid Production. Circulation 2022; 145:969-982. [PMID: 35193378 PMCID: PMC9365453 DOI: 10.1161/circulationaha.120.045373] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: The risk of cardiovascular disease in type 1 diabetes remains extremely high, despite marked advances in blood glucose control and even the widespread use of cholesterol synthesis inhibitors. Thus, a deeper understanding of insulin regulation of cholesterol metabolism, and its disruption in type 1 diabetes, could reveal better treatment strategies. Methods: To define the mechanisms by which insulin controls plasma cholesterol levels, we knocked down the insulin receptor, FoxO1, and the key bile acid synthesis enzyme, CYP8B1. We measured bile acid composition, cholesterol absorption, and plasma cholesterol. In parallel, we measured markers of cholesterol absorption and synthesis in humans with type 1 diabetes treated with ezetimibe and statins in a double-blind crossover study. Results: Mice with hepatic deletion of the insulin receptor showed marked increases in 12α-hydroxylated bile acids (12HBAs), cholesterol absorption, and plasma cholesterol. This phenotype was entirely reversed by hepatic deletion of FoxO1. FoxO1 is inhibited by insulin, and required for the production of 12HBAs, which promote intestinal cholesterol absorption and suppress hepatic cholesterol synthesis. Knockdown of Cyp8b1 normalized 12HBA levels and completely prevented hypercholesterolemia in mice with hepatic deletion of the insulin receptor (n=5-30) as well as mouse models of type 1 diabetes (n=5-22). In parallel, the cholesterol absorption inhibitor, ezetimibe, normalized cholesterol absorption and LDL-cholesterol in patients with type 1 diabetes as well as, or better than, the cholesterol synthesis inhibitor, simvastatin (n=20). Conclusions: Insulin, by inhibiting FoxO1 in the liver, reduces 12HBAs, cholesterol absorption, and plasma cholesterol levels. Thus, type 1 diabetes leads to a unique set of derangements in cholesterol metabolism, with increased absorption rather than synthesis. These derangements are reversed by ezetimibe, but not statins, which are currently the first line of lipid-lowering treatment in type 1 diabetes. Taken together, these data suggest that a personalized approach to lipid lowering in type 1 diabetes may be more effective and highlight the need for further studies specifically in this group of patients.
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Affiliation(s)
- Ivana Semova
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Amy E Levenson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Joanna Krawczyk
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | - Mary E Gearing
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Alisha V Ling
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Kathryn A Williams
- Biostatistics and Research Design Center, ICCTR, Boston Children's Hospital, Boston, MA
| | - Ji Miao
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Stuart S Adamson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Dong-Ju Shin
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Satyapal Chahar
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | | | - Lee R Hagey
- Department of Medicine, University of California, San Diego, CA
| | - David Vicent
- Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | - Sarah D de Ferranti
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Srividya Kidambi
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI
| | | | - Sudha B Biddinger
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
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Semova I, Levenson AE, Krawczyk J, Bullock K, Williams KA, Wadwa RP, Khoury PR, Kimball TR, Urbina EM, de Ferranti SD, Maahs DM, Dolan LM, Shah AS, Clish CB, Biddinger SB. Markers of cholesterol synthesis are elevated in adolescents and young adults with type 2 diabetes. Pediatr Diabetes 2020; 21:1126-1131. [PMID: 32738021 PMCID: PMC7855867 DOI: 10.1111/pedi.13097] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 07/07/2020] [Accepted: 07/28/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Changes in cholesterol absorption and cholesterol synthesis may promote dyslipidemia and cardiovascular disease in individuals with type 2 diabetes mellitus (T2DM). OBJECTIVE To assess cholesterol synthesis and absorption in lean individuals, obese individuals, and individuals with T2DM. METHODS We measured lathosterol and lanosterol (markers of cholesterol synthesis) as well as campesterol and β-sitosterol (markers of cholesterol absorption) in the serum of 15 to 26 years old individuals with T2DM (n = 95), as well as their lean (n = 98) and obese (n = 92) controls. RESULTS Individuals with T2DM showed a 51% increase in lathosterol and a 65% increase in lanosterol compared to lean controls. Similarly, obese individuals showed a 31% increase in lathosterol compared to lean controls. Lathosterol and lanosterol were positively correlated with body mass index, fasting insulin and glucose, serum triglycerides, and C-reactive protein, and negatively correlated with HDL-cholesterol. In contrast, campesterol and β-sitosterol were not altered in individuals with T2DM. Moreover, campesterol and β-sitosterol were negatively correlated with body mass index, fasting insulin, and C-reactive protein and were positively correlated with HDL-cholesterol. CONCLUSIONS Adolescents and young adults with T2DM show evidence of increased cholesterol synthesis compared to non-diabetic lean controls. These findings suggest that T2DM may promote cardiovascular disease by increasing cholesterol synthesis, and provide additional rationale for the use of cholesterol synthesis inhibitors in this group.
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Affiliation(s)
- Ivana Semova
- Division of Endocrinology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amy E. Levenson
- Division of Endocrinology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Joanna Krawczyk
- Division of Endocrinology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Kevin Bullock
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Kathryn A. Williams
- Division of Endocrinology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts,Biostatistics and Research Design Center, Boston Children’s Hospital, Boston, Massachusetts
| | - R. Paul Wadwa
- Barbara Davis Center for Diabetes, University of Colorado School of Medicine, Aurora, Colorado
| | - Philip R. Khoury
- Division of Cardiology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio
| | - Thomas R. Kimball
- Division of Cardiology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio
| | - Elaine M. Urbina
- Heart Institute, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio
| | - Sarah D. de Ferranti
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - David M. Maahs
- Barbara Davis Center for Diabetes, University of Colorado School of Medicine, Aurora, Colorado
| | - Lawrence M. Dolan
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio
| | - Amy S. Shah
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio
| | - Clary B. Clish
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Sudha B. Biddinger
- Division of Endocrinology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
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3
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Semova I, Levenson AE, Krawczyk J, Bullock K, Williams KA, Wadwa RP, Shah AS, Khoury PR, Kimball TR, Urbina EM, de Ferranti SD, Bishop FK, Maahs DM, Dolan LM, Clish CB, Biddinger SB. Type 1 diabetes is associated with an increase in cholesterol absorption markers but a decrease in cholesterol synthesis markers in a young adult population. J Clin Lipidol 2019; 13:940-946. [PMID: 31706902 PMCID: PMC6980756 DOI: 10.1016/j.jacl.2019.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/04/2019] [Accepted: 09/17/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND To optimize treatment and prevent cardiovascular disease in subjects with type 1 diabetes, it is important to determine how cholesterol metabolism changes with type 1 diabetes. OBJECTIVE The objective of the study was to compare plasma levels of campesterol and β-sitosterol, markers of cholesterol absorption, as well as lathosterol, a marker of cholesterol synthesis, in youth with and without type 1 diabetes. METHODS Serum samples were obtained from adolescent subjects with type 1 diabetes (n = 175, mean age 15.2 years, mean duration of diabetes 8.2 years) and without diabetes (n = 74, mean age 15.4 years). Campesterol, β-sitosterol, and lathosterol, were measured using targeted liquid chromatography tandem mass spectrometry, compared between groups, and correlated with the available cardiometabolic variables. RESULTS Campesterol and β-sitosterol levels were 30% higher in subjects with type 1 diabetes and positively correlated with hemoglobin A1c levels. In contrast, lathosterol levels were 20% lower in subjects with type 1 diabetes and positively correlated with triglycerides, body mass index, and systolic blood pressure. CONCLUSION Plasma markers suggest that cholesterol absorption is increased, whereas cholesterol synthesis is decreased in adolescent subjects with type 1 diabetes. Further studies to address the impact of these changes on the relative efficacy of cholesterol absorption and synthesis inhibitors in subjects with type 1 diabetes are urgently needed.
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Affiliation(s)
- Ivana Semova
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amy E Levenson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Joanna Krawczyk
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kevin Bullock
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Kathryn A Williams
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Biostatistics and Research Design Center, Boston Children's Hospital, Boston, MA, USA
| | - R Paul Wadwa
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO, USA
| | - Amy S Shah
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH, USA
| | - Philip R Khoury
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH, USA
| | - Thomas R Kimball
- Division of Cardiology, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH, USA
| | - Elaine M Urbina
- Division of Cardiology, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH, USA
| | - Sarah D de Ferranti
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Franziska K Bishop
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO, USA
| | - David M Maahs
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lawrence M Dolan
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, OH, USA
| | - Clary B Clish
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sudha B Biddinger
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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Non-Cholesterol Sterol Concentrations as Biomarkers for Cholesterol Absorption and Synthesis in Different Metabolic Disorders: A Systematic Review. Nutrients 2019; 11:nu11010124. [PMID: 30634478 PMCID: PMC6356200 DOI: 10.3390/nu11010124] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/21/2018] [Accepted: 12/28/2018] [Indexed: 12/27/2022] Open
Abstract
Non-cholesterol sterols are validated biomarkers for intestinal cholesterol absorption and endogenous cholesterol synthesis. However, their use in metabolic disturbances has not been systematically explored. Therefore, we conducted a systematic review to provide an overview of non-cholesterol sterols as markers for cholesterol metabolism in different metabolic disorders. Potentially relevant studies were retrieved by a systematic search of three databases in July 2018 and ninety-four human studies were included. Cholesterol-standardized levels of campesterol, sitosterol and cholestanol were collected to reflect cholesterol absorption and those of lathosterol and desmosterol to reflect cholesterol synthesis. Their use as biomarkers was examined in the following metabolic disorders: overweight/obesity (n = 16), diabetes mellitus (n = 15), metabolic syndrome (n = 5), hyperlipidemia (n = 11), cardiovascular disease (n = 17), and diseases related to intestine (n = 16), liver (n = 22) or kidney (n = 2). In general, markers for cholesterol absorption and synthesis displayed reciprocal patterns, showing that cholesterol metabolism is tightly regulated by the interplay of intestinal absorption and endogenous synthesis. Distinctive patterns for cholesterol absorption or cholesterol synthesis could be identified, suggesting that metabolic disorders can be classified as 'cholesterol absorbers or cholesterol synthesizers'. Future studies should be performed to confirm or refute these findings and to examine whether this information can be used for targeted (dietary) interventions.
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Differences in hepatic expression of genes involved in lipid homeostasis between hereditary hypertriglyceridemic rats and healthy Wistar rats and in their response to dietary cholesterol. Food Chem Toxicol 2009; 47:2624-30. [DOI: 10.1016/j.fct.2009.07.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 07/15/2009] [Accepted: 07/21/2009] [Indexed: 11/22/2022]
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Shay CM, Evans RW, Orchard TJ. Do plant sterol concentrations correlate with coronary artery disease in type 1 diabetes? A report from the Pittsburgh Epidemiology of Diabetes Complications Study. J Diabetes 2009; 1:112-7. [PMID: 20827426 PMCID: PMC2933944 DOI: 10.1111/j.1753-0407.2009.00012.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND It has been suggested that plant sterol absorption is increased in type 1 diabetes mellitus (T1DM) and that this may relate to the increased cardiovascular risk seen in T1DM. The cardiovascular benefit of lowering low-density lipoprotein-cholesterol with statin medication has also been shown to be influenced by plant sterol absorption. METHODS The relationship between sterol concentrations, coronary artery disease (CAD), and the use of statin medications in T1DM was compared between participants with CAD (Minnesota codes 1.1, 1.2, 1.3, 4.1-4.3, 5.1-5.3, and 7.1; n = 82), from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study, and those without (n = 213). Serum sterol concentrations reflecting cholesterol absorption (β-sitosterol and campesterol) and synthesis (desmosterol and lathosterol) were assayed and analyzed by gas chromatography and were expressed as a ratio of total cholesterol (×10(3)). RESULTS No differences were observed in markers of cholesterol absorption between individuals with and without CAD. In patients with CAD, significantly lower levels were observed for both sterol markers reflecting cholesterol synthesis compared with individuals without CAD [desmosterol: 0.34 vs 0.42, respectively (P = 0.003); lathosterol 0.47 vs 0.54, respectively (P = 0.019)]. Further stratification by statin medication use revealed significantly lower levels of synthesis-reflecting sterols in individuals taking statin medication, particularly those with CAD. CONCLUSIONS Although previous reports suggest that higher levels of cholesterol absorption in T1DM potentially increase cardiovascular risk in this population, the present data suggest no differences in cholesterol absorption between T1DM individuals with and without CAD.
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Affiliation(s)
- Christina Marie Shay
- Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA.
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7
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Hallikainen M, Lyyra-Laitinen T, Laitinen T, Moilanen L, Miettinen TA, Gylling H. Effects of plant stanol esters on serum cholesterol concentrations, relative markers of cholesterol metabolism and endothelial function in type 1 diabetes. Atherosclerosis 2007; 199:432-9. [PMID: 18062976 DOI: 10.1016/j.atherosclerosis.2007.10.033] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 10/29/2007] [Accepted: 10/29/2007] [Indexed: 11/19/2022]
Abstract
We investigated the effect of plant stanol esters (STAEST) on serum total and LDL cholesterol concentrations and endothelial function in subjects with type 1 diabetes (T1D). In addition, the changes in the relative serum markers of cholesterol metabolism were recorded. In a parallel, randomized, double-blind study the intervention group (n = 11) consumed STAEST spread (2g/day stanols) and the control group (n=8) the same spread containing no added stanols for 12 weeks. At baseline, brachial artery diameter was negatively correlated with serum HDL cholesterol concentration (r = -0.476, P < 0.05), but not with total or LDL cholesterol concentrations or serum non-cholesterol sterol ratios to cholesterol. Flow-mediated dilatation was positively associated with serum absorption marker ratios to cholesterol, significantly so with the sitosterol ratio (r = 0.467, P < 0.05). During the intervention, serum total and LDL cholesterol concentrations were reduced by 4.9 and 6.9% from baseline in the STAEST group, and by 10.8 and 16.1% from controls, respectively (P < 0.05 for all). No significant changes in HDL cholesterol and serum triglyceride concentrations were found. The STAEST consumption reduced serum campesterol and sitosterol ratios by 17-21% (P<0.05) from baseline, but the relative serum synthesis markers were not changed. Brachial artery diameter and flow-mediated dilatation did not change during the investigation. In conclusion, STAEST significantly reduced serum total and LDL cholesterol concentrations and serum plant sterol ratios without affecting HDL and triglyceride concentrations in subjects with T1D. STAEST had no effect on endothelial function.
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Affiliation(s)
- Maarit Hallikainen
- Department of Clinical Nutrition, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland.
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8
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Sittiwet C, Gylling H, Hallikainen M, Pihlajamäki J, Moilanen L, Laaksonen DE, Niskanen L, Agren JJ, Laakso M, Miettinen TA. Cholesterol metabolism and non-cholesterol sterol distribution in lipoproteins of type 1 diabetes: The effect of improved glycemic control. Atherosclerosis 2007; 194:465-72. [PMID: 16996519 DOI: 10.1016/j.atherosclerosis.2006.08.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 08/15/2006] [Accepted: 08/23/2006] [Indexed: 11/22/2022]
Abstract
In type 1 diabetes, the ratios to cholesterol of serum absorption markers, e.g., cholestanol, are elevated and those of synthesis markers, e.g., lathosterol, are reduced suggesting perturbed cholesterol metabolism. We studied 17 subjects with type 1 diabetes in poor glycemic control at baseline to assess whether improvement of glycemic control affects lathosterol and cholestanol ratios to cholesterol and their distribution in lipoproteins. Cholesterol and the non-cholesterol sterols were assayed directly from serum, and free and ester fractions after thin-layer chromatographic separation of lipoprotein sterols with gas-liquid chromatography. After the 2-6 months follow-up, the mean value of HbA1(c) decreased from 10.8% to 8.6% (p=0.001). Even though the concentrations of serum and lipoprotein cholesterol remained unchanged, the serum lathosterol to cholesterol ratio increased by 28% (p<0.05) and the lathosterol/cholestanol proportion by 23% (p<0.05). The ratios of total and esterified lathosterol to cholesterol in serum, chylomicrons and LDL, and free lathosterol to cholesterol in serum and IDL, were negatively associated with HbA1(c) at baseline and after follow-up, suggesting that the better glycemic control, the higher was cholesterol synthesis. The absorption markers were less consistently associated with HbA1(c). About half of the serum lathosterol and cholestanol was carried in LDL and one-fourth to one-fifth in HDL, but the lathosterol ratios were roughly similar in all lipoproteins. In contrast, cholestanol accumulated in chylomicrons and HDL. Glycemic control did not affect the distributions of lathosterol and cholestanol. In conclusion, improvement in glycemic control increased cholesterol synthesis, but had no effect on cholesterol absorption as measured by the serum or lipoprotein cholestanol to cholesterol ratio. From a clinical point of view, the better the glycemic control, the more antiatherogenic cholesterol metabolism may be in type 1 diabetes.
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Affiliation(s)
- Chaiyasit Sittiwet
- Department of Medicine, Division of Internal Medicine, University of Helsinki, Helsinki, Finland
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9
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Järvisalo M, Raitakari O, Gylling H, Miettinen TA. Cholesterol absorption and synthesis in children with type 1 diabetes. Diabetes Care 2006; 29:2300-4. [PMID: 17003310 DOI: 10.2337/dc05-2235] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The levels of the surrogate markers of cholesterol absorption (cholestanol and plant sterols) and synthesis (cholesterol precursors) in serum have suggested that in adult type 1 diabetes, cholesterol absorption is high and synthesis is low compared with type 2 diabetic or control subjects. Accordingly, these findings were further studied in children with type 1 diabetes. RESEARCH DESIGN AND METHODS Forty-eight children with diabetes were compared with 79 age- and sex-matched control subjects. The serum ratios of cholesterol absorption and synthesis markers were measured with gas-liquid chromatography. The study population was divided into triads (combining the two lowest triads) by serum cholestanol ratios of the control subjects indicating low to high cholesterol absorption efficiency. RESULTS The ratios of the absorption and synthesis markers were similar in case and control subjects, and they were negatively related to each other in control subjects, being less consistent in diabetic patients. Thus, high cholesterol absorption was associated with low synthesis. Plant sterol ratios increased significantly with increasing cholestanol triads in both groups, but the values in the lowest triads were higher in case versus control subjects. CONCLUSIONS Homeostasis between cholesterol absorption and synthesis is maintained in control children and somewhat less consistently in those with diabetes. The higher plant sterol ratios in diabetic versus control subjects in the lowest cholestanol triads suggest that cholesterol absorption is higher in children with diabetes versus control subjects but only within the range of low cholesterol absorption.
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Affiliation(s)
- Mikko Järvisalo
- Centre for Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland
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10
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Tsujinaka K, Nakamura T, Maegawa H, Fujimiya M, Nishio Y, Kudo M, Kashiwagi A. Diet high in lipid hydroperoxide by vitamin E deficiency induces insulin resistance and impaired insulin secretion in normal rats. Diabetes Res Clin Pract 2005; 67:99-109. [PMID: 15649568 DOI: 10.1016/j.diabres.2004.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Revised: 03/26/2004] [Accepted: 06/09/2004] [Indexed: 10/26/2022]
Abstract
To clarify the effect of dietary lipid hydroperoxide (LPO) on development of glucose intolerance, we fed Sprague-Dawley rats on a diet containing elevated LPO level for 10 weeks and measured both insulin sensitivity and insulin secretion. The contents of LPO in both plasma and skeletal muscle in the LPO-fed rats were significantly higher than those in the controls. Both insulin resistance evaluated by steady-state blood glucose (SSBG) methods and impaired insulin secretion evaluated by oral glucose tolerance test (OGTT) were found in the LPO-fed rats as compared with control rats. Furthermore, the levels of insulin receptor substrate (IRS)-1 protein in the skeletal muscle were significantly lower in the LPO-fed rats. Those impairments were not reversed in LPO-fed rats with supernormal levels of plasma vitamin E following vitamin E supplementation for 5 weeks. Moreover, the immunohistochemical study revealed that NF-kappaB-p50 protein was found in the nucleus of pancreatic beta-cells of the LPO-fed rats, whereas it was not observed in the nucleus of the islets in the control rats. These findings indicate that NF-kappaB is activated in response to oxidative stress in pancreatic islet cells in LPO-fed rats. In conclusion, our studies reveal that diet high in LPO by vitamin E deficiency accelerates glucose intolerance through impairments of both sensitivity and secretion of insulin.
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Affiliation(s)
- Katsumasa Tsujinaka
- The Division of Endocrinology and Metabolism, Department of Medicine, Seta, Otsu, Shiga 520-2192, Japan
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11
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Abstract
Little information is available on cholesterol absorption and synthesis in human type 1 diabetes. We studied these variables using serum cholesterol precursor sterol ratios to cholesterol as surrogate markers of cholesterol synthesis and those of cholestanol and plant sterols to reflect cholesterol absorption in seven type 1 diabetic subjects and in five age- and body weight-matched control subjects. Total and lipoprotein cholesterol levels were similar, but triglycerides in intermediate-density lipoprotein (IDL) and LDL were higher in type 1 diabetic than in control subjects. Most of the marker sterols were transported by LDL and HDL in both groups. The percentage of esterified cholesterol was lower in triglyceride-rich lipoproteins in diabetic patients than in control subjects. The ratios of the absorption marker sterols in serum were higher, and those of the synthesis markers were lower in type 1 diabetic than in control subjects. The increased cholestanol ratios were seen in all lipoproteins, and those of free and total plant sterols were mainly in LDL, whereas the decreased free and total synthesis markers were mainly in all lipoproteins. In conclusion, high absorption and low synthesis marker sterols seem to characterize human type 1 diabetes. These findings could be related to low expression of ABC G/5 G/8 genes, resulting in high absorption of cholesterol and sterols in general and low synthesis of cholesterol compared with type 2 diabetes.
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Affiliation(s)
- Helena Gylling
- Department of Clinical Nutrition, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland.
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12
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Miettinen TA, Gylling H, Tuominen J, Simonen P, Koivisto V. Low synthesis and high absorption of cholesterol characterize type 1 diabetes. Diabetes Care 2004; 27:53-8. [PMID: 14693966 DOI: 10.2337/diacare.27.1.53] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Streptozotocin-induced type 1 diabetes in experimental animals inhibits cholesterol synthesis and increases cholesterol absorption. In contrast to human type 2 diabetes, virtually no information is available on cholesterol synthesis and absorption in type 1 diabetes. RESEARCH DESIGN AND METHODS We studied the variables of cholesterol metabolism in 27 patients with type 1 diabetes and in 10 patients with type 2 diabetes matched for body weight, using cholesterol precursor sterol ratios to cholesterol as surrogate markers of synthesis, and those of cholestanol and plant sterols of cholesterol absorption. Glucose control was good in all subjects. RESULTS Total and HDL cholesterol and LDL triglycerides were higher in type 2 than in type 1 diabetes. Serum sterols, measured also in VLDL, intermediate-density lipoprotein (IDL), LDL, and HDL, were transported up to >90% by LDL and HDL in type 1 diabetes. The ratios of all absorption sterols in serum and in each lipoprotein were higher, and those of the synthesis markers, especially cholestenol and lathosterol, were lower in type 1 than in type 2 diabetes. CONCLUSIONS In contrast to type 2 diabetes, the findings in type 1 diabetes could be related to low expression of ABC G/5 G/8 genes, resulting in high absorption of cholesterol and sterols in general and low synthesis of cholesterol.
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Affiliation(s)
- Tatu A Miettinen
- Division of Internal Medicine, Department of Medicine, University of Helsinki, Helsinki, Finland.
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13
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Bloks VW, Bakker-Van Waarde WM, Verkade HJ, Kema IP, Wolters H, Vink E, Groen AK, Kuipers F. Down-regulation of hepatic and intestinal Abcg5 and Abcg8 expression associated with altered sterol fluxes in rats with streptozotocin-induced diabetes. Diabetologia 2004; 47:104-12. [PMID: 14618236 DOI: 10.1007/s00125-003-1261-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2003] [Revised: 07/28/2003] [Indexed: 12/27/2022]
Abstract
AIM/HYPOTHESIS Type I diabetes is associated with altered hepatic bile formation and increased intestinal cholesterol absorption. The aim of this study was to evaluate whether altered expression of the ATP-Binding Cassette half-transporters Abcg5 and Abcg8, recently implicated in control of both hepatobiliary cholesterol secretion and intestinal cholesterol absorption, contributes to changed cholesterol metabolism in experimental diabetes. METHODS mRNA and protein expression of Abcg5 and Abcg8 were determined in the liver and intestine of rats with streptozotozin-induced diabetes and related to relevant metabolic parameters in plasma, liver and bile. RESULTS Hepatic mRNA expression of both Abcg5 (-76%) and Abcg8 (-71%) was reduced in diabetic rats when compared to control rats. In spite of increased HDL cholesterol, considered a major source of biliary cholesterol, secretion of the sterol into bile relative to that of bile salts was reduced by 65% in diabetic animals. Intestinal mRNA expression of Abcg5 (-47%) and Abcg8 (-43%) as well as Abcg5 protein contents were also reduced in insulin-deficient animals. This was accompanied by a three- to four-fold increase in plasma beta-sitosterol and campesterol concentrations and by a doubling of the calculated apparent cholesterol absorption. These effects partially normalized upon insulin supplementation. CONCLUSION/INTERPRETATION Our data indicate that effects of insulin-deficiency on bile composition and cholesterol absorption in rats are, at least partly, attributable to changes in hepatic and intestinal Abcg5 and Abcg8 expression.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily G, Member 5
- ATP Binding Cassette Transporter, Subfamily G, Member 8
- ATP-Binding Cassette Transporters/genetics
- Animals
- Apolipoprotein A-I/metabolism
- Bile/metabolism
- Cholesterol/analogs & derivatives
- Cholesterol/blood
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Gene Expression Regulation
- Intestinal Mucosa/metabolism
- Lipoproteins/genetics
- Liver/metabolism
- Male
- Phytosterols
- RNA, Messenger/genetics
- Rats
- Rats, Wistar
- Sitosterols/blood
- Transcription, Genetic/genetics
- Triglycerides/metabolism
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Affiliation(s)
- V W Bloks
- Center for Liver, Digestive and Metabolic Diseases, University Hospital Groningen, Groningen, The Netherlands
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Li D, Sinclair AJ. Macronutrient innovations: The role of fats and sterols in human health. Asia Pac J Clin Nutr 2002. [DOI: 10.1046/j.1440-6047.11.s6.4.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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