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Gumede NM, Lembede BW, Brooksbank RL, Erlwanger KH, Chivandi E. β-Sitosterol Shows Potential to Protect Against the Development of High-Fructose Diet-Induced Metabolic Dysfunction in Female Rats. J Med Food 2020; 23:367-374. [DOI: 10.1089/jmf.2019.0120] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Nontobeko M. Gumede
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Busisani W. Lembede
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Richard L. Brooksbank
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Kennedy H. Erlwanger
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Eliton Chivandi
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Gumede NM, Lembede BW, Nkomozepi P, Brooksbank RL, Erlwanger KH, Chivandi E. β-Sitosterol mitigates the development of high-fructose diet-induced nonalcoholic fatty liver disease in growing male Sprague–Dawley rats. Can J Physiol Pharmacol 2020; 98:44-50. [PMID: 31560861 DOI: 10.1139/cjpp-2019-0295] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fructose contributes to the development of nonalcoholic fatty liver disease (NAFLD). β-Sitosterol (Bst), a naturally occurring phytosterol, has antihyperlipidaemic and hepatoprotective properties. This study interrogated the potential protective effect of β-sitosterol against NAFLD in growing rats fed a high-fructose diet, modelling children fed obesogenic diets. Forty-four 21 day old male rat pups were randomly allocated to and administered the following treatments for 12 weeks: group I, standard rat chow (SRC) + plain drinking water (PW) + plain gelatine cube (PC); group II, SRC + 20% w/v fructose solution (FS) as drinking fluid + PC; group III, SRC + FS + 100 mg/kg fenofibrate in a gelatine cube; group IV, SRC + FS + 20 mg/kg β-sitosterol gelatine cube (Bst); group V, SRC + PW + Bst. Terminally, the livers were dissected out, weighed, total liver lipid content determined, and histological analyses done. Harvested plasma was used to determine the surrogate biomarkers of liver function. The high-fructose diet caused increased (p < 0.05) hepatic lipid (total) accretion (>10% liver mass), micro- and macrovesicular hepatic steatosis, and hepatic inflammation. β-Sitosterol and fenofibrate prevented the high-fructose diet-induced macrovesicular steatosis and prevented the progression of NAFLD to steatohepatitis. β-Sitosterol can prospectively be used to mitigate diet-induced NAFLD.
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Affiliation(s)
- Nontobeko M. Gumede
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, Republic of South Africa
| | - Busisani W. Lembede
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, Republic of South Africa
| | - Pilani Nkomozepi
- Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Doornfontein, Johannesburg, Republic of South Africa
| | - Richard L. Brooksbank
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, Republic of South Africa
| | - Kennedy H. Erlwanger
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, Republic of South Africa
| | - Eliton Chivandi
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, Republic of South Africa
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Raymond AR, Brooksbank RL, Millen AME, Norton GR, Solomon A, Woodiwiss AJ, Tsang L, Dessein PH, Gonzalez-Gay MA. Telomere length, endothelial activation and carotid atherosclerosis in black and white African patients with rheumatoid arthritis. Clin Exp Rheumatol 2016; 34:864-871. [PMID: 27157144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 02/15/2016] [Indexed: 06/05/2023]
Abstract
OBJECTIVES Our objective was to examine associations of traditional and non-traditional cardiovascular risk factors with relative leukocyte telomere length and confounder adjusted relationships of relative telomere length with endothelial activation and carotid atherosclerosis in black and white African patients with rheumatoid arthritis (RA). METHODS Relative telomere length of leukocyte DNA in whole blood was determined using quantitative RT-PCR in 205 (101 black) African patients with RA. RESULTS In demographic characteristic adjusted analysis, relative telomere length tended to be larger in black compared to white patients (median (IQR)=0.54 (0.42-0.54) and 0.48 (0.37-0.60) (p=0.07), respectively). In black patients, waist circumference, systolic, diastolic and mean blood pressure were associated with relative telomere length (β (SE)=-0.00270 (0.00114) (p=0.02), -0.00185 (0.00060) (p=0.003), -0.00243 (0.00112) (p=0.03) and -0.00225 (0.00075) (p=0.003), respectively); in white patients, age, anti-cyclic citrullinated antibody positivity, biologic agent use, a cholesterol-HDL cholesterol ratio of >4 and the number of major traditional risk factors were related to relative telomere length (β (SE) =-0.00242 (0.00113) (p=0.03), 0.06629 (0.03374) (p=0.05), -0.09321 (0.04310) (p=0.03), 0.08225 (0.03420) (p=0.02) and 0.04046 (0.01719) (p=0.02), respectively). One SD increase in relative telomere length was associated with carotid plaque (OR (95% CI)=1.65 (0.99-2.75) (p=0.05)) and vascular cell adhesion molecule-1 concentrations (β (SE)=-0.05031 (0.02480) (p=0.04)) in black and white patients, respectively. CONCLUSIONS This study disclosed paradoxically direct relationships between relative telomere length and cardiovascular risk factors in white and atherosclerosis in black African RA patients. The role of relative telomere length in cardiovascular risk and its stratification in RA requires longitudinal investigation.
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Affiliation(s)
- Andrew R Raymond
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Richard L Brooksbank
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Aletta M E Millen
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gavin R Norton
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Ahmed Solomon
- Department of Rheumatology, Charlotte Maxeke Johannesburg Academic Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Angela J Woodiwiss
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Linda Tsang
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick H Dessein
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, Univ.of the Witwatersrand, Johannesburg, South Africa; and Rheumatology Division, Universitair Ziekenhuis & Vrije Universiteit, Brussels, Belgium
| | - Miguel A Gonzalez-Gay
- Cardiovascular Pathophysiol. & Genomics Res. Unit, Univ.of the Witwatersrand, Johannesburg, South Africa; & Epidemiol., Genetics & Atherosclerosis Res., Systemic Inflammatory Dis, Rheumatol.Div., Hosp.Univ. Marques de Valdecilla, IDIVAL, Santander, Spain
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Raymond AR, Becker J, Woodiwiss AJ, Booysen HL, Norton GR, Brooksbank RL. Ethanol-Associated Cardiomyocyte Apoptosis and Left Ventricular Dilation Are Unrelated to Changes in Myocardial Telomere Length in Rats. J Card Fail 2016; 22:294-302. [DOI: 10.1016/j.cardfail.2015.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/07/2015] [Accepted: 06/15/2015] [Indexed: 12/26/2022]
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Raymond AR, Norton GR, Woodiwiss AJ, Brooksbank RL. Impact of gender and menopausal status on relationships between biological aging, as indexed by telomere length, and aortic stiffness. Am J Hypertens 2015; 28:623-30. [PMID: 25413841 DOI: 10.1093/ajh/hpu212] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/06/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Telomere length predicts cardiovascular disease (CVD) possibly through an impact of telomere attrition on aortic stiffness. Whether reduced biological aging and a lack of telomere length-aortic stiffness relationships in women contribute to the lower prevalence of CVD in women, prior to menopause, is uncertain. METHODS We evaluated the relationship between telomere length and carotid-femoral (aortic) pulse wave velocity (PWV) in 580 randomly recruited participants of Black African descent (age = 44 ± 19 years; women: n = 361; premenopausal: n = 195). PWV was determined using carotid and femoral applanation tonometry (SphygmoCor). Relative leukocyte telomere length (T/S) was measured using quantitative real-time polymerase chain reaction assays. RESULTS Men and women had similar T/S. T/S was inversely correlated with age (r = -0.14, P < 0.001) and this association was similar in all (r = -0.14, P < 0.01) and premenopausal (r = -0.17, P < 0.05) women as in men (r = -0.14, P < 0.05). An inverse relationship between T/S and PWV was noted both before (r = -0.20, P < 0.0001) and after (partial r = -0.14, P < 0.001) adjustments for confounders. No interaction between T/S and either sex or menopausal status was independently associated with PWV, and T/S was independently correlated with PWV in all (partial r = -0.14, P < 0.01) and premenopausal (partial r = -0.18, P < 0.05) women and in men (partial r = -0.15, P < 0.05). CONCLUSIONS Gender and premenopausal status do not affect age-related decreases in T/S and associations between T/S and PWV. In participants of African descent in whom telomere length did not differ by gender, the impact of gender prior to menopause on CVD is unlikely to be attributed to differences in the effect of biological aging on aortic stiffness.
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Affiliation(s)
- Andrew R Raymond
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gavin R Norton
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Angela J Woodiwiss
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Richard L Brooksbank
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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Raymond AR, Hodson B, Woodiwiss AJ, Norton GR, Brooksbank RL. Telomere length and adrenergic-induced left ventricular dilatation and systolic chamber dysfunction in rats. Eur J Appl Physiol 2013; 113:2803-11. [DOI: 10.1007/s00421-013-2722-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 08/30/2013] [Indexed: 12/15/2022]
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Raymond AR, Norton GR, Sareli P, Woodiwiss AJ, Brooksbank RL. Relationship between average leucocyte telomere length and the presence or severity of idiopathic dilated cardiomyopathy in black Africans. Eur J Heart Fail 2012; 15:54-60. [PMID: 23035035 DOI: 10.1093/eurjhf/hfs147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS A reduced average leucocyte telomere length is associated with ischaemic heart failure. Whether this relationship represents a cause or consequence of heart failure or is attributed to associated risk factors and coronary artery disease is uncertain. We evaluated if average leucocyte telomere length is associated with idiopathic dilated cardiomyopathy (IDC) or its severity. METHODS AND RESULTS We compared average leucocyte telomere length in 223 patients with heart failure due to IDC and 227 healthy controls of black African ancestry. We also evaluated the relationship between average leucocyte telomere length and left ventricular ejection fraction (LVEF). LVEF was determined using echocardiography and radionuclide multiple-gated acquisition (MUGA) scan in patients with IDC. Relative leucocyte telomere length (T/S) was measured using a quantitative real-time polymerase chain reaction assay. Log T/S was negatively correlated with age in patients with IDC (P = 0.0007) and in controls (P = 0.030), and with alcohol consumption (P = 0.032) and regular smoking (P = 0.021) in patients with IDC. Log T/S did not differ between IDC and control groups either before (P = 0.11) or after (IDC = 0.071 ± 0.187, control = 0.071 ± 0.187, P = 0.99) adjustments for confounders. Log T/S was not associated with echocardiographic (P = 0.47) or MUGA (P = 0.99) LVEF or LV end-diastolic diameter (LVEDD) (P = 0.34) in patients with IDC. With adjustments for age, sex, alcohol consumption, and smoking, log T/S was similarly not associated with echocardiographic (P = 0.60) or MUGA (P = 0.91) LVEF or LVEDD (P = 0.53) in patients with IDC. CONCLUSIONS Average relative leucocyte telomere length is not associated with IDC or its severity in groups of black African ancestry.
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Affiliation(s)
- Andrew R Raymond
- Cardiovasular Pathophysiology and Genomics Research Unit, School of Physiology, University of the Witwatersrand Medical School, Parktown, Johannesburg, South Africa.
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Brooksbank RL, Badenhorst ME, Isaacs H, Savage N. Treatment of normal skeletal muscle with FK506 or rapamycin results in halothane-induced muscle contracture. Anesthesiology 1998; 89:693-8. [PMID: 9743407 DOI: 10.1097/00000542-199809000-00020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND FKBP12 is a protein that is closely associated with the ryanodine receptor type 1 of skeletal muscle and modulates Ca2+ release by the channel. The immunosuppressants FK506 and rapamycin both bind to FKBP12 and in turn dissociate the protein from the ryanodine receptor. By treating healthy human skeletal muscle strips with FK506 or rapamycin and then subjecting the strips to the caffeine-halothane contracture test, this study determined that FK506 and rapamycin alter the sensitivity of the muscle strip to halothane, caffeine, or both. METHODS Skeletal muscle strips from 10 healthy persons were incubated in Krebs medium equilibrated with a 95% oxygen and 5% carbon dioxide mixture, which contained either 12 microM FK506 (n = 8) or 12 microM rapamycin (n = 6), for 15 min at 37 degrees C. The strips were subjected to the caffeine-halothane contracture test for malignant hyperthermia according to the European Malignant Hyperthermia Group protocol. RESULTS Treatment of normal skeletal muscle strips with FK506 and rapamycin resulted in halothane-induced contractures of 0.44+/-0.16 g and 0.6+/-0.49 g, respectively, at 2% halothane. CONCLUSIONS The results obtained show that pre-exposure of healthy skeletal muscle strips to either FK506 or rapamycin is sufficient to give rise to halothane-induced contractures. This is most likely caused by destabilization of Ca2+ release by the ryanodine receptor as a result of the dissociation of FKBP12. This finding suggests that a mutation in FKBP12 or changes in its capacity to bind to the ryanodine receptor could alter the halothane sensitivity of the skeletal muscle ryanodine receptor and thereby predispose the person to malignant hyperthermia.
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Affiliation(s)
- R L Brooksbank
- Department of Physiology, University of the Witwatersrand Medical School, Parktown, Johannesburg, South Africa.
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Mizrahi V, Brooksbank RL, Nkabinde NC. Mutagenesis of the conserved aspartic acid 443, glutamic acid 478, asparagine 494, and aspartic acid 498 residues in the ribonuclease H domain of p66/p51 human immunodeficiency virus type I reverse transcriptase. Expression and biochemical analysis. J Biol Chem 1994; 269:19245-9. [PMID: 7518454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The effects of point mutations of the conserved Asp443, Glu478, Asn494, and Asp498 residues in the RNase H domain of human immunodeficiency virus type I (HIV-1) reverse transcriptase (RT) have been analyzed. The mutants fell into two classes: (i) functional RT, but not detectable ribonuclease H activity, and (ii) uncharacterizable phenotype due to protein instability in the context of the RT/protease Escherichia coli co-expression system (Mizrahi, V., Lazarus, G. M., Miles, L. M., Meyers, C. A., and Debouck, C. (1989) Arch. Biochem. Biophys. 273, 347-358). The only mutation in the former class was D443A, whereas those in the latter included D443E, E478D, E478Q, D498E, D443A/D498N, D443E/D498N, D443Q/D498N, N494A, N494D, and N494Q. The results were interpreted in terms of the x-ray crystal structure of the HIV-1 RNase H domain (Davies, J. F., II, Hostomaska, Z., Hostomsky, Z., Jordan, S. R., and Matthews, D. A. (1991) Science 252, 88-95) and a general acid-general base hydrolysis mechanism (Katayanagi, K., Okumura, M., and Morikawa, K. (1993) Proteins Struct. Funct. Genet. 17, 337-346). The data suggested that structural perturbations within the RNase H domain interfered with maturation of the pol precursor by HIV-1 protease. Analysis of selected D443/D498 double mutants suggested that the destabilization caused by the D498N mutation could be suppressed by the formation of a new hydrogen bond between Asn498 and Asn443.
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Affiliation(s)
- V Mizrahi
- Molecular Biology Unit, South African Institute for Medical Research, Johannesburg
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