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1.
The lipid raft markers stomatin, prohibitin, flotillin, and HflK/C (SPFH)-domain proteins form an operon with NfeD proteins and function with apolar polyisoprenoid lipids.
Yokoyama, H, Matsui, I
Critical reviews in microbiology. 2020;(1):38-48
Abstract
SPFH-domain proteins are found in almost all organisms across three domains: archaea, bacteria, and eukaryotes. In eukaryotic organelles, their subfamilies exhibit overlapping distribution and functions; thus, the rationality of annotation to discriminate these subfamilies remains unclear. In this review, the binding ability of prokaryotic SPFH-domain proteins towards nonpolar polyisoprenoides such as squalene and lycopene, rather than cholesterol, is discussed. The hydrophobic region at the C-terminus of SPFH-domain proteins constitutes the main region that binds apolar polyisoprenoid lipids as well as cholesterol and substantively contributes towards lipid raft formation as these regions are self-assembled together with specific lipids. Because the scaffolding proteins caveolins show common topological properties with SPFH-domain proteins such as stomatin and flotillin, the α-helical segments of stomatin proteins can flexibly move along with the membrane surface, with such movement potentially leading to membrane bending via lipid raft clustering through the formation of high order homo-oligomeric complexes of SPFH-domain proteins. We also discuss the functional significance and ancient origin of SPFH-domain proteins and the NfeD protein (STOPP) operon, which can be traced back to the ancient living cells that diverged and evolved to archaea and bacteria. Based on the molecular mechanism whereby the STOPP-protease degrades the C-terminal hydrophobic clusters of SPFH-domain proteins, it is conceivable that STOPP-protease might control the physicochemical properties of lipid rafts.
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2.
The influence of dietary fatty acids on liver fat content and metabolism.
Hodson, L, Rosqvist, F, Parry, SA
The Proceedings of the Nutrition Society. 2020;(1):30-41
Abstract
Non-alcoholic fatty liver disease encompasses a spectrum of conditions from hepatic steatosis through to cirrhosis; obesity is a known risk factor. The liver plays a major role in regulating fatty acid metabolism and perturbations in intrahepatic processes have potential to impact on metabolic health. It remains unclear why intra-hepatocellular fat starts to accumulate, but it likely involves an imbalance between fatty acid delivery to the liver, fatty acid synthesis and oxidation within the liver and TAG export from the liver. As man spends the majority of the day in a postprandial rather than postabsorptive state, dietary fatty acid intake should be taken into consideration when investigating why intra-hepatic fat starts to accumulate. This review will discuss the impact of the quantity and quality of dietary fatty acids on liver fat accumulation and metabolism, along with some of the potential mechanisms involved. Studies investigating the role of dietary fat in liver fat accumulation, although surprisingly limited, have clearly demonstrated that it is total energy intake, rather than fat intake per se, that is a key mediator of liver fat content; hyperenergetic diets increase liver fat whilst hypoenergetic diets decrease liver fat content irrespective of total fat content. Moreover, there is now, albeit limited evidence emerging to suggest the composition of dietary fat may also play a role in liver fat accumulation, with diets enriched in saturated fat appearing to increase liver fat content to a greater extent when compared with diets enriched in unsaturated fats.
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3.
Effects of Statins on Lipid Profile of Kidney Transplant Recipients: A Meta-Analysis of Randomized Controlled Trials.
Huang, X, Jia, Y, Zhu, X, Zhang, Y, Jiang, L, Wei, X, Zhao, D, Zhao, X, Du, Y
BioMed research international. 2020;:9094543
Abstract
OBJECTIVE To assess the benefits of statins on lipid profile in kidney transplant recipients via a meta-analysis. METHODS We systematically identified peer-reviewed clinical trials, review articles, and treatment guidelines from PubMed, Embase, the Cochrane Library, Wanfang, Chinese National Knowledge Infrastructure (CNKI), SinoMed (CBM), and Chongqing VIP databases from inception to April 2019. In the analysis, only randomized controlled clinical trials performed in human were included. RESULTS Eight articles were included in the analysis, involving 335 kidney transplant recipients who received statins and 350 kidney transplant patients as the control group. Results revealed that statins improved the lipid profile of kidney transplant recipients. Specifically, statin therapy significantly reduced total cholesterol and low-density lipoprotein cholesterol. However, it had no effects on high-density lipoprotein cholesterol and triglyceride levels. CONCLUSIONS The present study provides valuable knowledge on the potential benefits of statins in kidney transplant recipients. This meta-analysis shows that statin therapy modifies the lipid profile in this patient population.
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4.
Dipeptidyl peptidase-4 inhibitor anagliptin reduces fasting apolipoprotein B-48 levels in patients with type 2 diabetes: A randomized controlled trial.
Onoue, T, Goto, M, Wada, E, Furukawa, M, Okuji, T, Okada, N, Kobayashi, T, Iwama, S, Sugiyama, M, Tsunekawa, T, et al
PloS one. 2020;(1):e0228004
Abstract
Type 2 diabetes and dyslipidemia are diseases that collectively increase the risk of patients developing cardiovascular complications. Several incretin-based drugs are reported to improve lipid metabolism, and one of these medications, anagliptin, is a dipeptidyl peptidase-4 (DPP-4) inhibitor that has been shown to decrease serum triglyceride and low-density lipoproteins cholesterol. This study aimed to conduct an investigation into the effects of anagliptin on serum lipid profiles. This multicenter, open-label, randomized (1:1), parallel group study was designed to evaluate the effects of anagliptin on serum lipid profiles (triglycerides, lipoproteins, apolipoproteins, and cholesterol fractions). The study involved 24 patients with type 2 diabetes at two participating hospitals for a period of 24 weeks. Patients were randomly assigned to the anagliptin (n = 12) or control (n = 12) groups. Patients in the anagliptin group were treated with 200 mg of the drug twice daily. Patients in the control group did not receive anagliptin, but continued with their previous treatment schedules. Lipid metabolism was examined under fasting conditions at baseline and 24 weeks. Patients treated with anagliptin for 24 weeks exhibited significantly reduced levels of serum apolipoprotein B-48, a marker for lipid transport from the intestine, compared with the control group patients (P < 0.05). After 24 weeks of treatment, serum adiponectin levels were significantly raised, whereas glycated hemoglobin (HbA1c) levels were significantly lower compared with the baseline in the anagliptin group (P < 0.05), but not in the control group. This study showed that the DPP-4 inhibitor anagliptin reduces fasting apolipoprotein B-48 levels, suggesting that this drug may have beneficial effects on lipid metabolism possibly mediated by the inhibition of intestinal lipid transport.
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5.
Obesity, Bioactive Lipids, and Adipose Tissue Inflammation in Insulin Resistance.
Kojta, I, Chacińska, M, Błachnio-Zabielska, A
Nutrients. 2020;(5)
Abstract
Obesity is a major risk factor for the development of insulin resistance and type 2 diabetes. The exact mechanism by which adipose tissue induces insulin resistance is still unclear. It has been demonstrated that obesity is associated with the adipocyte dysfunction, macrophage infiltration, and low-grade inflammation, which probably contributes to the induction of insulin resistance. Adipose tissue synthesizes and secretes numerous bioactive molecules, namely adipokines and cytokines, which affect the metabolism of both lipids and glucose. Disorders in the synthesis of adipokines and cytokines that occur in obesity lead to changes in lipid and carbohydrates metabolism and, as a consequence, may lead to insulin resistance and type 2 diabetes. Obesity is also associated with the accumulation of lipids. A special group of lipids that are able to regulate the activity of intracellular enzymes are biologically active lipids: long-chain acyl-CoAs, ceramides, and diacylglycerols. According to the latest data, the accumulation of these lipids in adipocytes is probably related to the development of insulin resistance. Recent studies indicate that the accumulation of biologically active lipids in adipose tissue may regulate the synthesis/secretion of adipokines and proinflammatory cytokines. Although studies have revealed that inflammation caused by excessive fat accumulation and abnormalities in lipid metabolism can contribute to the development of obesity-related insulin resistance, further research is needed to determine the exact mechanism by which obesity-related insulin resistance is induced.
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6.
Investigating the effect of antiretroviral switch to tenofovir alafenamide on lipid profiles in people living with HIV.
Lacey, A, Savinelli, S, Barco, EA, Macken, A, Cotter, AG, Sheehan, G, Lambert, JS, Muldoon, E, Feeney, E, Mallon, PW, et al
AIDS (London, England). 2020;(8):1161-1170
Abstract
BACKGROUND Whilst reporting improved renal and bone safety profiles, studies have noted changes in lipid profiles among people living with HIV (PLWH) receiving antiretroviral therapy (ART) switching away from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF). We aimed to characterize changes in lipids observed after switching to TAF-containing ART in a real-world setting. METHODS A prospective study on PLWH enrolled in the UCD-ID Cohort study who switched to TAF-containing ART. Routine laboratory data [including lipids (total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglycerides], ART history and use of lipid-lowering therapy (LLT) were analysed preswitch and postswitch to TAF. Dyslipidaemia was classified according to the National Cholesterol Education Program-Adult Panel III (NCEP-ATP III). Change in lipid parameters and change in the proportion of individuals with dyslipidaemia postswitch was assessed using the paired t-test and the Stuart--Maxwell test, respectively. RESULTS Of 775 PLWH enrolled in the cohort, 238 switched to TAF containing ART, of whom 194 had both preswitch and postswitch lipids measured a median (IQR) 24 (14-41) weeks postswitch to TAF. TC, LDL, HDL, triglycerides and TC : HDL ratio significantly increased postswitch [mean change (SE) mmol/l; +0.37 (0.06), P < 0.001; +0.25 (0.06), P < 0.001; +0.05 (0.02), P = 0.003, +0.13 (0.07), P = 0.02, and +0.16 (0.08), P = 0.013) respectively]. There were significant increases in the proportions of PLWH with more severe dyslipidaemia postswitch across TC and LDL (both P < 0.001). CONCLUSION These data suggest clinically relevant, worsening lipid profiles postswitch to TAF, with a larger proportion of PLWH exceeding recommended lipid thresholds postswitch. How these changes will impact on cardiovascular risk or need for LLT remains to be determined.
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7.
Role of dyslipidemia in accelerating inflammation, autoimmunity, and atherosclerosis in systemic lupus erythematosus and other autoimmune diseases.
Wang, Y, Yu, H, He, J
Discovery medicine. 2020;(159):49-56
Abstract
Dyslipidemia refers to the abnormality of lipid metabolism. The aberrant lipid profiles are usually characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC), triglycerides (TGs), apoprotein B (ApoB), and decreased level of high-density lipoprotein cholesterol (HDL-c). Dyslipidemia occurs frequently in autoimmune diseases (ADs), such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), type-1 diabetes mellitus (T1DM), psoriasis, and inflammatory bowel disease (IBD), and many other diseases. An imbalance in lipid metabolism contributes to accelerated inflammatory responses in addition to promoting the formation of atherosclerosis. Although there have been many studies and reports on the relationship between abnormal lipid metabolism and ADs, it remains uncertain as to whether dyslipidemia has a unique role in promoting the occurrence and development of ADs. Here, we discuss the mechanisms of how dyslipidemia accelerates inflammatory response, autoimmunity, and atherosclerosis at epidemiological, molecular, and cellular levels, and the discussion is mainly conducted with SLE as an example.
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8.
Effect of Acute Caffeine Intake on the Fat Oxidation Rate during Exercise: A Systematic Review and Meta-Analysis.
Collado-Mateo, D, Lavín-Pérez, AM, Merellano-Navarro, E, Coso, JD
Nutrients. 2020;(12)
Abstract
A number of previous investigations have been designed to determine the effect of acute caffeine intake on the rate of fat oxidation during exercise. However, these investigations have shown contradictory results due to the differences in the exercise protocols used or the co-ingestion of caffeine with other substances. Hence, to date, there is no consensus about the effect of caffeine on fat oxidation during exercise. The purpose of this study was to conduct a systematic review followed by a meta-analysis to establish the effect of acute intake of caffeine (ranging from 2 to 7 mg/kg of body mass) on the rate of fat oxidation during exercise. A total of 19 studies published between 1978 and 2020 were included, all of which employed crossover experimental designs in which the ingestion of caffeine was compared to a placebo. Studies were selected if the exercise intensity was consistent in the caffeine and placebo trials and if these were preceded by a fasting protocol. A subsequent meta-analysis was performed using the random effects model to calculate the standardized mean difference (SMD). The meta-analysis revealed that caffeine significantly (p = 0.008) increased the fat oxidation rate (SMD = 0.73; 95% CI = 0.19 to 1.27). This increment was consistent with a significant (p = 0.04) reduction of the respiratory exchange ratio (SMD = -0.33; 95% CI = -0.65 to -0.01) and a significant (p = 0.049) increase in the oxygen uptake (SMD = 0.23; 95% CI = 0.01 to 0.44). The results also showed that there was a dose-response effect of caffeine on the fat oxidation rate, indicating that more than 3.0 mg/kg is necessary to obtain a statistically significant effect of this stimulant on fat oxidation during exercise. Additionally, the ability of caffeine to enhance fat oxidation during exercise was higher in sedentary or untrained individuals than in trained and recreational athletes. In conclusion, pre-exercise intake of a moderate dose of caffeine may effectively increase fat utilization during aerobic exercise of submaximal intensity performed after a fasting period. However, the fitness level of the participant may modulate the magnitude of the effect of caffeine on fat oxidation during exercise.
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9.
Comparative effects of 18 antipsychotics on metabolic function in patients with schizophrenia, predictors of metabolic dysregulation, and association with psychopathology: a systematic review and network meta-analysis.
Pillinger, T, McCutcheon, RA, Vano, L, Mizuno, Y, Arumuham, A, Hindley, G, Beck, K, Natesan, S, Efthimiou, O, Cipriani, A, et al
The lancet. Psychiatry. 2020;(1):64-77
Abstract
BACKGROUND Antipsychotic treatment is associated with metabolic disturbance. However, the degree to which metabolic alterations occur in treatment with different antipsychotics is unclear. Predictors of metabolic dysregulation are poorly understood and the association between metabolic change and change in psychopathology is uncertain. We aimed to compare and rank antipsychotics on the basis of their metabolic side-effects, identify physiological and demographic predictors of antipsychotic-induced metabolic dysregulation, and investigate the relationship between change in psychotic symptoms and change in metabolic parameters with antipsychotic treatment. METHODS We searched MEDLINE, EMBASE, and PsycINFO from inception until June 30, 2019. We included blinded, randomised controlled trials comparing 18 antipsychotics and placebo in acute treatment of schizophrenia. We did frequentist random-effects network meta-analyses to investigate treatment-induced changes in body weight, BMI, total cholesterol, LDL cholesterol, HDL cholesterol, triglyceride, and glucose concentrations. We did meta-regressions to examine relationships between metabolic change and age, sex, ethnicity, baseline weight, and baseline metabolic parameter level. We examined the association between metabolic change and psychopathology change by estimating the correlation between symptom severity change and metabolic parameter change. FINDINGS Of 6532 citations, we included 100 randomised controlled trials, including 25 952 patients. Median treatment duration was 6 weeks (IQR 6-8). Mean differences for weight gain compared with placebo ranged from -0·23 kg (95% CI -0·83 to 0·36) for haloperidol to 3·01 kg (1·78 to 4·24) for clozapine; for BMI from -0·25 kg/m2 (-0·68 to 0·17) for haloperidol to 1·07 kg/m2 (0·90 to 1·25) for olanzapine; for total-cholesterol from -0·09 mmol/L (-0·24 to 0·07) for cariprazine to 0·56 mmol/L (0·26-0·86) for clozapine; for LDL cholesterol from -0·13 mmol/L (-0.21 to -0·05) for cariprazine to 0·20 mmol/L (0·14 to 0·26) for olanzapine; for HDL cholesterol from 0·05 mmol/L (0·00 to 0·10) for brexpiprazole to -0·10 mmol/L (-0·33 to 0·14) for amisulpride; for triglycerides from -0·01 mmol/L (-0·10 to 0·08) for brexpiprazole to 0·98 mmol/L (0·48 to 1·49) for clozapine; for glucose from -0·29 mmol/L (-0·55 to -0·03) for lurasidone to 1·05 mmol/L (0·41 to 1·70) for clozapine. Greater increases in glucose were predicted by higher baseline weight (p=0·0015) and male sex (p=0·0082). Non-white ethnicity was associated with greater increases in total cholesterol (p=0·040) compared with white ethnicity. Improvements in symptom severity were associated with increases in weight (r=0·36, p=0·0021), BMI (r=0·84, p<0·0001), total-cholesterol (r=0·31, p=0·047), and LDL cholesterol (r=0·42, p=0·013), and decreases in HDL cholesterol (r=-0·35, p=0·035). INTERPRETATION Marked differences exist between antipsychotics in terms of metabolic side-effects, with olanzapine and clozapine exhibiting the worst profiles and aripiprazole, brexpiprazole, cariprazine, lurasidone, and ziprasidone the most benign profiles. Increased baseline weight, male sex, and non-white ethnicity are predictors of susceptibility to antipsychotic-induced metabolic change, and improvements in psychopathology are associated with metabolic disturbance. Treatment guidelines should be updated to reflect our findings. However, the choice of antipsychotic should be made on an individual basis, considering the clinical circumstances and preferences of patients, carers, and clinicians. FUNDING UK Medical Research Council, Wellcome Trust, National Institute for Health Research Oxford Health Biomedical Research Centre.
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10.
Lipid composition of the cancer cell membrane.
Szlasa, W, Zendran, I, Zalesińska, A, Tarek, M, Kulbacka, J
Journal of bioenergetics and biomembranes. 2020;(5):321-342
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Abstract
Cancer cell possesses numerous adaptations to resist the immune system response and chemotherapy. One of the most significant properties of the neoplastic cells is the altered lipid metabolism, and consequently, the abnormal cell membrane composition. Like in the case of phosphatidylcholine, these changes result in the modulation of certain enzymes and accumulation of energetic material, which could be used for a higher proliferation rate. The changes are so prominent, that some lipids, such as phosphatidylserines, could even be considered as the cancer biomarkers. Additionally, some changes of biophysical properties of cell membranes lead to the higher resistance to chemotherapy, and finally to the disturbances in signalling pathways. Namely, the increased levels of certain lipids, like for instance phosphatidylserine, lead to the attenuation of the immune system response. Also, changes in lipid saturation prevent the cells from demanding conditions of the microenvironment. Particularly interesting is the significance of cell membrane cholesterol content in the modulation of metastasis. This review paper discusses the roles of each lipid type in cancer physiology. The review combined theoretical data with clinical studies to show novel therapeutic options concerning the modulation of cell membranes in oncology.