Browsing by Subject "Lipids"
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- ItemOpen Access9β Polymorphism of the Glucocorticoid Receptor Gene Appears to Have Limited Impact in Patients with Addison’s Disease(Public Library of Science, 2014) Ross, Ian Louis; Dandara, Collet; Swart, Marelize; Lacerda, Miguel; Schatz, Desmond; Blom, Dirk JacobusBACKGROUND: Addison’s disease (AD) has been associated with an increased risk of cardiovascular disease. Glucocorticoid receptor polymorphisms that alter glucocorticoid sensitivity may influence metabolic and cardiovascular risk factors in patients with AD. The 9β polymorphism of the glucocorticoid receptor gene is associated with relative glucocorticoid resistance and has been reported to increase the risk of myocardial infarction in the elderly. We explored the impact of this polymorphism in patients with AD. Materials and METHODS: 147 patients with AD and 147 age, gender and ethnicity matched healthy controls were recruited. Blood was taken in a non-fasted state for plasma lipid determination, measurement of cardiovascular risk factors and DNA extraction. RESULTS: Genotype data for the 9β polymorphism was available for 139 patients and 146 controls. AD patients had a more atherogenic lipid profile characterized by an increase in the prevalence of small dense LDL (p = 0.003), increased triglycerides (p = 0.002), reduced HDLC (p<0.001) an elevated highly sensitive C-reactive protein (p = 0.01), compared with controls. The 9β polymorphism (at least one G allele) was found in 28% of patients and controls respectively. After adjusting for age, gender, ethnicity, BMI and hydrocortisone dose per metre square of body surface area in patients, there were no significant metabolic associations with this polymorphism and hydrocortisone doses were not higher in patients with the polymorphism. CONCLUSIONS: This study did not identify any associations between the 9β polymorphism and cardiovascular risk factors or hydrocortisone dose and determination of this polymorphism is therefore unlikely to be of clinical benefit in the management of patients with AD.
- ItemOpen AccessAnti-retroviral therapy increases the prevalence of dyslipidemia in South African HIV-infected patients(Public Library of Science, 2016) Dave, Joel A; Levitt, Naomi S; Ross, Ian L; Lacerda, Miguel; Maartens, Gary; Blom, DirkPurpose Data on the prevalence of dyslipidaemia and associated risk factors in HIV-infected patients from sub-Saharan Africa is sparse. We performed a cross-sectional analysis in a cohort of HIV-infected South African adults. METHODS: We studied HIV-infected patients who were either antiretroviral therapy (ART)-naive or receiving non-nucleoside reverse transcriptase inhibitor (NNRTI)-based or protease inhibitor (PI)-based ART. Evaluation included fasting lipograms, oral glucose tolerance tests and clinical anthropometry. Dyslipidemia was defined using the NCEP ATPIII guidelines. RESULTS: The median age of the participants was 34 years (range 19-68 years) and 78% were women. The prevalence of dyslipidemia in 406 ART-naive and 551 participants on ART was 90.0% and 85%, respectively. Low HDL-cholesterol (HDLC) was the most common abnormality [290/406 (71%) ART-naïve and 237/551 (43%) ART- participants]. Participants on ART had higher triglycerides (TG), total cholesterol (TC), LDL-cholesterol (LDLC) and HDLC than the ART-naïve group. Severe dyslipidaemia, (LDLC> 4.9 mmol/L or TG >5.0 mmol/L) was present in <5% of participants. In multivariate analyses there were complex associations between age, gender, type and duration of ART and body composition and LDLC, HDLC and TG, which differed between ART-naïve and ART-participants. CONCLUSION: Participants on ART had higher TG, TC, LDLC and HDLC than those who were ART-naïve but severe lipid abnormalities requiring evaluation and treatment were uncommon.
- ItemOpen AccessAssociation of serum leptin and adiponectin with anthropomorphic indices of obesity, blood lipids and insulin resistance in a Sub-Saharan African population(2016) Ayina, Clarisse Noël A; Noubiap, Jean Jacques N; Etoundi Ngoa, Laurent Serge; Boudou, Philippe; Gautier, Jean François; Mengnjo, Michel Karngong; Mbanya, Jean Claude; Sobngwi, EugèneAbstract Background There is little data on the metabolic effects of adipokines in sub-Saharan African populations. This study aimed to explore the potential relationship of leptin and adiponectin, with obesity, plasma lipids and insulin resistance in a Cameroonian population. Methods We enrolled 167 men and 309 women aged ≥18 years from the general population in Cameroon. Data were collected on waist circumference (WC), body mass index (BMI), waist-to-hip ratio (WHR), body fat (BF%), fasting blood glucose, plasma lipids, adiponectin, leptin, insulin and homeostasis model for assessment of insulin resistance (HOMA-IR). Pearson’s correlation and multiple stepwise linear regression analyses were used to determine correlates of leptin and adiponectin serum levels. Results The prevalence of obesity was higher in women compared to men (p < 0.0001), and Central obesity which is more prevalent particularly in women (WC = 42.4 %, WHR = 42.3 %), is almost for 90 % comparable to %BF (42.7 %). Adiponectin negatively with BMI (r = −0.294, p < 0.0001), WC (r = −0.294, p < 0.0001), %BF (r = −0.122, p = 0.028), WHR (r = −0.143, p = 0.009), triglycerides (r = −0.141, p = 0.011), HOMA-IR (r = −0.145, p = 0.027) and insulin (r = −0.130, p = 0.048). Leptin positively correlated with BMI (r = 0.628), WC (r = 0.530), BF% (r = 0.720), (all p < 0.0001); with DBP (r = 0.112, p = 0.043), total cholesterol (r = 0.324, p < 0.0001), LDL-cholesterol (r = 0.298, p < 0.0001), insulin (r = 0.320, p < 0.001 and HOMA-IR (r = 0.272, p < 0.0001). In multiple stepwise regression analysis, adiponectin was negatively associated with WC (β = −0.38, p = 0.001) and BF% (β = 0.33, p < 0.0001), while leptin was positively associated with BF% (β = 0.60, p < 0.0001), total cholesterol (β = 0.11, p = 0.02) and HOMA-IR (β = 0.11, p = 0.02). When controlled for gender, HOMA-IR was found significantly associated to adiponectin (β = 0.13, p = 0.046), but not BF%, while the association previously found between leptin and HOMA-IR disappeared; BMI and WC were significantly associated with leptin (β = 0.18, p = 0.04 & β = 0.19, p = 0.02 respectively). Conclusion This study, which includes a population who was not receiving potentially confounding medications, confirms the associations previously observed of adiponectin with reduced adiposity especially central adiposity and improved insulin sensitivity. Confirmatory associations were also observed between leptin and obesity, blood lipids and insulin resistance for the first time in an African population. Gender was significant covariate interacting with insulin sensitivity/insulin resistance and obesity indexes associations in this population.
- ItemOpen AccessCardiovascular risk factors in patients with Addison's disease: a comparative study of South African and Swedish patients(Public Library of Science, 2014) Ross, Ian Louis; Bergthorsdottir, Ragnhildur; Levitt, Naomi; Dave, Joel Alex; Schatz, Desmond; Marais, David; Johannsson, GudmundurBACKGROUND: Patients with Addison's disease (AD) in Scandinavia have an increased risk for premature death due to cardiovascular disease (CVD). Serum lipids are important risk factors for CVD and vascular mortality. Replacement doses of hydrocortisone have historically been higher in Sweden than South Africa. The primary aim was to study the lipid profiles in a large group of patients with AD with the hypothesis that the lipid profile in patients in Sweden would be worse than in South Africa. METHODS: In a cross-sectional study, 110 patients with AD (55 from South Africa, 55 from Sweden) matched for age, gender, ethnicity and BMI were studied. Anthropometric measures, blood pressure, lipids, highly sensitive C-reactive protein (hs-CRP) and adiponectin were studied. RESULTS: All patients were Caucasian and the majority were women N = 36 (65.5%). Mean (standard deviation; SD) ages of the Swedish and South African patients were 52.9 (13.0) and 52.6 (14.4) years and BMI 25.3 (3.2) and 25.8 (4.1) kg/m 2 , respectively. The mean total daily hydrocortisone dose was greater in the Swedish patients than the South African patients, [33.0 (8.1) versus 24.3 (8.0) mg; p<0.0001]. South African patients had higher median (interquartilerange; IQR) triglycerides (TG) [1.59 (1.1-2.46) versus 0.96 (0.74-1.6) mmol/l; p<0.001], total cholesterol (TC) [6.02(1.50) versus 5.13 (0.87) mmol/l; p<0.001], LDL-C [4.43 (1.44) versus 2.75 (0.80) mmol/l; p<0.001] and median hs-CRP [2.15 (0.93-5.45) versus 0.99 (0.57-2.10) mg/L; p<0.003] and lower HDL-C [0.80 (0.40) versus 1.86 (0.46) mmol/l; p<0.001] than the Swedish patients. Approximately 20% of the patients in both cohorts had hypertension and diabetes mellitus. CONCLUSIONS: South African patients with AD have worse lipid profiles and higher hs-CRP compared to their matched Swedish patients, despite lower doses of hydrocortisone. It is uncertain at this time whether these are due to genetic or environmental factors.
- ItemOpen AccessConjugated linoleic acid versus high-oleic acid sunflower oil: effects on energy metabolism, glucose tolerance, blood lipids, appetite and body composition in regularly exercising individuals(2007) Lambert, Estelle V; Goedecke, Julia H; Bluett, Kerry; Heggie, Kerry; Claassen, Amanda; Rae, Dale E; West, Sacha; Dugas, Jonathan; Dugas, Lara; Meltzer, Shelly; Charlton, Karen; Mohede, IngeThe aim of this study was to measure the effects of 12 weeks of conjugated linoleic acid (CLA) supplementation on body composition, RER, RMR, blood lipid profiles, insulin sensitivity and appetite in exercising, normal-weight persons. In this double-blind, randomised, controlled trial, sixty-two non-obese subjects (twenty-five men, thirty-seven women) received either 3.9 g/d CLA or 3.9 g high-oleic acid sunflower oil for 12 weeks. Prior to and after 12 weeks of supplementation, oral glucose tolerance, blood lipid concentrations, body composition (dual-energy X-ray absorptiometry and computerised tomography scans), RMR, resting and exercising RER and appetite were measured. There were no significant effects of CLA on body composition or distribution, RMR, RER or appetite. During the oral glucose tolerance tests, mean plasma insulin concentrations (0, 30, 120 min) were significantly lower (P= 0.04) in women who supplemented with CLA (24.3 (SD 9.7) to 20.4 (SD 8.5) microU/ml) compared to high-oleic acid sunflower oil control (23.7 (SD 9.8) to 26.0 (SD 8.8) microU/ml). Serum NEFA levels in response to oral glucose were attenuated in both men and women in the CLA (P=0.001) compared to control group. However, serum total cholesterol and LDL-cholesterol concentrations decreased in both groups and HDL-cholesterol concentrations decreased in women over 12 weeks (P=0.001, P=0.02, P=0.02, respectively). In conclusion, mixed-isomer CLA supplementation had a favourable effect on serum insulin and NEFA response to oral glucose in non-obese, regularly exercising women, but there were no CLA-specific effects on body composition, energy expenditure or appetite.
- ItemOpen AccessDecreased production of low density lipoprotein by atorvastatin after apheresis in homozygous familial hypercholesterolemia(1997) Marais, A David; Naoumova, R P; Firth, J C; Penny, C; Neuwirth, C K Y; Thompson, G RApheresis only partially controls raised low density lipoprotein cholesterol levels in patients with homozygous familial hypercholesterolemia, who usually respond poorly to lipid-lowering drugs. The efficacy and mechanism of action of a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, atorvastatin, was therefore investigated in seven homozygotes undergoing apheresis. One receptor-negative and six receptor-defective homozygotes undergoing plasma exchange or LDL apheresis every 2 weeks were studied during 2 months each on placebo and on atorvastatin 80 mg daily. Changes in plasma lipids and mevalonic acid, an index of cholesterol synthesis, were measured and the kinetics of the rebound of low density lipoprotein cholesterol and apolipoprotein B after apheresis were analyzed. All subjects had significant improvements on atorvastatin. Mean decreases in low density lipoprotein cholesterol were 31% greater both pre- and post-apheresis on atorvastatin compared with placebo, accompanied by a 63% decrease in mevalonic acid. Percentage changes in low density lipoprotein cholesterol and mevalonic acid were closely correlated (r = 0.89, P = 0.007). The mean production rates of low density lipoprotein cholesterol and apolipoprotein B were 21% and 25% lower, respectively, on atorvastatin than on placebo (P < 0.005 and <0.02) but changes in mean fractional clearance rates were not statistically significant. We conclude that atorvastatin enhances the efficacy of plasma exchange and low density lipoprotein apheresis in patients who lack low density lipoprotein receptors. This effect appears to be due to marked inhibition of cholesterol synthesis which results in a decreased rate of production of low density lipoprotein.
- ItemOpen AccessErratum to: Investigation of the association between the TCF7L2 rs7903146 (C/T) gene polymorphism and obesity in a Cameroonian population: a pilot study(2017) Nguimmo-Metsadjio, Aurelie; Atogho-Tiedeu, Barbara; Noubiap, Jean Jacques; Evehe, Marie-Solange; Djokam-Dadjeu, Rosine; Donfack, Olivier Sontsa; Nanfa, Dieudonne; Mato, Edith Pascale M; Ngwa, Elvis Ndonwi; Guewo-Fokeng, Magellan; Pokam-Fosso, Priscille; Mbacham, Wilfred F; Mbanya, Jean Claude; Sobngwi, EugèneOBJECTIVE: This study aimed at investigating the association between the rs7903146 (C/T) polymorphism of the TCF7L2 gene with obesity in a Cameroonian population. METHOD: This was a case-control pilot study including 61 obese and 61 non-obese Cameroonian adults. Anthropometric indices of obesity, blood pressure, fasting blood glucose, and blood lipids were measured. The rs7903146 (C/T) polymorphism of the TCF7L2 gene was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and genotypes were correlated with clinical and biological parameters. RESULTS: The T allele was predominant in the study population with a frequency of 93%. No statistically significant difference was however observed between the genotypic (p = 0.50) and allelic frequencies (p = 0.58) of obese and non-obese subjects. Comparison of clinical and biochemical parameters of C allele carriers (CX = CC + CT) with those of TT genotype showed that there was no significant difference between the lipid profile of these two groups. CONCLUSION: The rs7903146 (C/T) polymorphism of the TCF7L2 gene might not be associated with obesity in the Cameroonian population.
- ItemOpen AccessLipoprotein lipase activity is decreased in a large cohort of patients with coronary artery disease and is associated with changes in lipids and lipoproteins(1999) Hockman, Dorit; Henderson,Howard E; Hockman, Dorit; Kastelein, John P; Zwinderman, Aeilko H; Gagné, Eric; Jukema, J Wouter; Reymer, Paul W A; Groenemeyer, Björn E; Hockman, Dorit; Lie, Kong I; Bruschke, Albert V G; Hayden, Michael R; Jansen, HansLipoprotein lipase (LPL) is crucial in the hydrolysis of triglycerides (TG) in TG-rich lipoproteins in the formation of HDL particles. As both these lipoproteins play an important role in the pathogenesis of atherosclerotic vascular disease, we sought to assess the relationship between post-heparin LPL (PH-LPL) activity and lipids and lipoproteins in a large, well-defined cohort of Dutch males with coronary artery disease (CAD). These subjects were drawn from the REGRESS study, totaled 730 in number and were evaluated against 75 healthy, normolipidemic male controls. Fasting mean PH-LPL activity in the CAD subjects was 108 46 mU/ml, compared to 138 44 mU/ml in controls (P < 0.0001). When these patients were divided into activity quartiles, those in the lowest versus the highest quartile had higher levels of TG (P < 0.001), VLDLc and VLDL-TG (P = 0.001). Conversely, levels of TC, LDL, and HDLc were lower in these patients (P = 0.001, P = 0.02, and P = 0.001, respectively). Also, in this cohort PH-LPL relationships with lipids and lipoproteins were not altered by apoE genotypes. The frequency of common mutations in the LPL gene associated with partial LPL deficiency (N291S and D9N carriers) in the lowest quartile for LPL activity was more than double the frequency in the highest quartile (12.0% vs. 5.0%; P = 0.006). By contrast, the frequency of the S447X LPL variant rose from 11.5% in the lowest to 18.3% (P = 0.006) in the highest quartile. This study, in a large cohort of CAD patients, has shown that PH-LPL activity is decreased (22%; P = 0.001) when compared to controls; that the D9N and N291S, and S447X LPL variants are genetic determinants, respectively, in CAD patients of low and high LPL PH-LPL activities; and that PH-LPL activity is strongly associated with changes in lipids and lipoproteins.
- ItemOpen AccessLipoprotein metabolism and its derangements(2003) Marais, DavidThe purpose of this article is to provide the medical practitioner with an understanding of lipids, lipoproteins and their metabolism and disorders. Such an understanding would enhance the assimilation of the sections on clinical assessment and treatment of dyslipoproteinaemia. Lipids may be defined as organic chemicals that are insoluble in water. In the biological context lipids are either carboxylic acids (fatty acids) or sterols, and their derivatives. Lipids are less dense than water and will float spontaneously or under centrifugal force. Cholesterol is the principal sterol in the animal kingdom and promotes the impenetrability of the phospholipid bilayer that constitutes the cell membrane. Additionally cholesterol is found in lipoproteins and in bile and is used to synthesise hormones and bile acids.
- ItemOpen AccessOsteoprotegerin in relation to insulin resistance and blood lipids in sub-Saharan African women with and without abdominal obesity(2015) Ayina Ayina, Clarisse Noël; Sobngwi, Eugène; Essouma, Mickael; Noubiap, Jean Jacques N; Boudou, Philippe; Etoundi Ngoa, Laurent Serge; Gautier, Jean FrançoisBackgroundOsteoprotegerin (OPG), a soluble member of the tumor necrosis factor receptor superfamily that inhibits bone resorption, has been suggested as a potential marker of cardiovascular risk. This study aimed to assess the relationship between insulin resistance, lipid profile and OPG levels in obese and non-obese sub-Saharan African women.MethodsSixty obese (44) and non-obese (16) volunteer women aged 18 to 40years were recruited in this cross-sectional study. Their clinical (age, height, weight, waist circumference, systolic and diastolic blood pressures) and biochemical parameters (fasting blood glucose, total cholesterol, high density lipoprotein-cholesterol (HDL-C)) were measured using standard methods. Insulin levels were measured using an electrochemiluminescence immunoassay, while OPG levels were measured using the ELISA technique. Low density lipoprotein-cholesterol (LDL-C), body mass index (BMI) and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) were calculated using standard methods. Abdominal obesity was defined as a waist circumference ≥ 80cm.ResultsOPG levels were higher in obese than in normal subjects, though the difference was not significant (p = 0.9). BMI, waist circumference, percent body fat and systolic blood pressure were significantly higher in obese than in non-obese subjects (p < 0.05). In these subjects, only age significantly correlated with OPG levels (r = 0.831, p = 0.003), while none of the anthropometric nor metabolic parameter did, even after adjustment for age. In obese subjects, OPG levels fairly correlated with HDL-C (r = 0.298, p = 0.058), and significantly correlated with HOMA-IR (r = −0.438, p = 0.018). After adjustment for age, OPG levels remained negatively correlated to HOMA-IR (r = −0.516, p = 0.020) and LDL-C (r = −0.535, p = 0.015) and positively correlated to HDL-C (r = 0.615, p = 0.004). In multiple linear regression analysis, age was a main determinant of OPG levels in non-obese (β = 0.647, p = 0.006) and obese (β = 0.356, p = 0.044) women. HDL-C was also associated to OPG levels in obese women (β = 0.535, p = 0.009).ConclusionThe positive correlation of OPG with HDL-C and HOMA-IR, and its negative correlation with LDL-C suggest that it may be a marker of insulin sensitivity/resistance and atherogenic risk in obese African women.
- ItemOpen AccessSensory neuropathy and metabolic risk factors in human immune deficiency virus infected South Africans receiving protease inhibitors(2015) Vermaak, John-Randel; Dave, Joel A; Levitt, Naomi; Heckmann, Jeannine MBackgroundProtease inhibitors (PI)s have been associated with distal sensory polyneuropathy (DSP) and metabolic complications in high-income countries. No data exist in Africans where second-line antiretroviral therapy (ART) often include PIs.MethodWe performed a cross-sectional study to assess the DSP frequency and metabolic risk factors in community-based South Africans taking ritonavir-boosted lopinavir as PI. Examination findings categorized subjects as having DSP (≥1 neuropathic sign) or symptomatic DSP [DSP with symptom(s)]. Fasting-state glucose and lipid profiles were assessed. We compared the ritonavir/lopinavir-group to a nested group on first-line ART [dideoxy-nucleoside reverse transcriptase inhibitors (d-drugs)] selected from a dataset collected at the same time and matched for d-drug exposure.ResultsThe ritonavir/lopinavir-group (n=86) consisted predominantly of women (84%) with a median age of 36years (IQR 32–41). The median current CD4+ count was 489cells/μL (IQR 291–665). The median exposure time to ritonavir/lopinavir was 18months (IQR 10–26) and to d-drugs, 24months (IQR 16–38). DSP was present in 78% and symptomatic DSP in 48%; symptoms were most frequently of moderate intensity. Only age independently associated with DSP and symptomatic DSP (p=0.08 and p=0.04, respectively). None of the metabolic syndrome components showed associations with DSP or symptomatic DSP despite a trend towards hypertriglyceridemia overall. The ritonavir/lopinavir-group had less DSP compared to the d-drug only group (p=0.002) but the frequency of symptomatic DSP was similar (p=0.49).ConclusionRitonavir-boosted lopinavir did not add additional risk to developing DSP in this community-based African cohort after a median of 18months on second-line ART.Electronic supplementary materialThe online version of this article (doi:10.1186/s12981-015-0073-8) contains supplementary material, which is available to authorized users.
- ItemOpen AccessThe composition of certain lipids in man : a comparative study of lipids in total serum, in the serum B-lipoprotein fraction and in arterial atheromatous plaques in certain groups of people(1964) Young, Gerardine Olga; Brock, J FIn recent years biochemical studies have played an important role in research into the pathogenesis of ischaemic heart disease. A large number of these studies have been concerned with the relationship between serum lipids and ischaemic heart disease (I.H.D.), which has been defined by the World Health Organization (1957) as "the cardiac disability, acute and chronic, arising from reduction or arrest of blood supply to the myocardium in association with disease processes in the coronary arterial system".
- ItemOpen AccessUnsaturated glycerophospholipids mediate heme crystallization: biological implications for hemozoin formation in the kissing bug Rhodnius prolixus(Public Library of Science, 2014) Stiebler, Renata; Majerowicz, David; Knudsen, Jens; Gondim, Katia C; Wright, David W; Egan, Timothy J; Oliveira, Marcus FHemozoin (Hz) is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus , Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes (PMVM). Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML) in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient β-hematin formation by means of two kinetically distinct mechanisms: an early and fast component, followed by a late and slow one. The fastest reactions observed were induced by unsaturated forms of phosphatidylethanolamine (uPE) and phosphatidylcholine (uPC), with half-lives of 0.04 and 0.7 minutes, respectively. β-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to β-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9-17.7 minutes) than those induced by uPC and uPE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, β-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus midgut.