Atherosclerosis, diabetes and lipoproteins

Adsorption of Acylhydroperoxy-Derivatives of Phospholipids from Biomembranes by Blood Plasma Lipoproteins

It has been established that acylhydroperoxy derivatives of phospholipids from oxidized rat liver mitochondria are captured predominantly by LDL particles but not by HDL during co-incubation with blood plasma lipoproteins, which refutes the previously suggested hypothesis about the involvement of HDL in the reverse transport of oxidized phospholipids and confirms the possibility of different mechanisms of lipohydroperoxide accumulation in LDL during oxidative stress.

Establishment and validation of a nomogram for progression to diabetic foot ulcers in elderly diabetic patients

Background

Many diabetic patients develop and progress to diabetic foot ulcers, which seriously affect health and quality of life and cause great economic and psychological stress, especially in elderly diabetic patients who often have various underlying diseases, and the consequences of their progression to diabetic foot ulcers are more serious and seriously affect elderly patients in surgery. Therefore, it is particularly important to analyze the influencing factors related to the progression of elderly diabetic patients to diabetic foot, and the column line graph prediction model is drawn based on regression analysis to derive the influencing factors of the progression of elderly diabetic patients to diabetic foot, and the total score derived from the combination of various influencing factors can visually calculate the probability of the progression of elderly diabetic patients to diabetic foot.

Objective

The influencing factors of progression deterioration to diabetic foot in elderly diabetic patients based on LASSO regression analysis and logistics regression analysis, and the column line graph prediction model was established by statistically significant risk factors.

Methods

The clinical data of elderly diabetic patients aged 60 years or older in the orthopedic ward and endocrine ward of the Third Hospital of Shanxi Medical University from 2015-01-01 to 2021-12-31 were retrospectively analyzed and divided into a modeling population (211) and an internal validation population (88) according to the random assignment principle. Firstly, LASSO regression analysis was performed based on the modeling population to screen out the independent influencing factors for progression to diabetic foot in elderly diabetic patients; Logistics univariate and multifactor regressions were performed by the screened influencing factors, and then column line graph prediction models for progression to diabetic foot in elderly diabetic patients were made by these influencing factors, using ROC (subject working characteristic curve) and AUC (their area under the curve), C-index validation, and calibration curve to initially evaluate the model discrimination and calibration. Model validation was performed by the internal validation set, and the ROC curve, C-index and calibration curve were used to further evaluate the column line graph model performance. Finally, using DCA (decision curve analysis), we observed whether the model could be used better in clinical settings.

Results and conclusions

(1) LASSO (Least absolute shrinkage and selection operator) regression analysis yielded a more significant significance on risk factors for progression to diabetic foot in elderly diabetic patients, such as age, presence of peripheral neuropathy, history of smoking, duration of disease, serum lactate dehydrogenase, and high-density cholesterol; (2) Based on the influencing factors and existing theories, a column line graph prediction model for progression to diabetic foot in elderly diabetic patients was constructed. The working characteristic curves of subjects in the training group and their area under the curve (area under the curve = 0.840) were also analyzed simultaneously with the working characteristic curves of subjects in the external validation population and their area under the curve (area under the curve = 0.934), which finally showed that the model was effective in predicting column line graphs; (iii) the C-index in the modeled cohort was 0.840 (95%CI: 0.779-0.901) and the C-index in the validation cohort was 0.934 (95%CI: 0.887-0.981), indicating that the model had good predictive accuracy; the calibration curve fit was good; (iv) the results of the decision curve analysis showed that the model would have good results in clinical use; (v) it indicated that the established predictive model for predicting progression to diabetic foot in elderly diabetic patients had good test efficacy and helped clinically screen the possibility of progression to diabetic foot in elderly diabetic patients and give personalized interventions to different patients in time.

Comparative Susceptibility to Oxidation of Different Classes of Blood Plasma Lipoproteins

The kinetics of free radical peroxidation of different classes of blood plasma lipoproteins (nanoparticles involved in lipid transport in the body) was studied. The susceptibility of atherogenic low-density lipoproteins (LDLs) to the Cu2+-initiated free radical peroxidation in vitro was found to be more than ten times higher than that of antiatherogenic high density lipoproteins (HDLs). The baseline content of acyl hydroperoxy derivatives of phospholipids (primary products of free radical peroxidation) in the outer layer of LDL particles in vivo measured per particle exceeded the baseline content of these compounds in HDL particles by more than an order of magnitude. The susceptibility to oxidation of the HDL₂ subfraction of HDLs was higher than the susceptibility of total HDL fraction and HDL₃ subfraction. The data obtained confirm an important role of free radical peroxidation of LDLs in the molecular mechanisms of vascular wall damage in atherosclerosis.

Antiobesity and Antidiabetic Effects of Portulaca oleracea Powder Intake in High-Fat Diet-Induced Obese C57BL/6 Mice

This study investigated the hypothesis that Portulaca oleracea L. exerts antiobesity and antidiabetic effects by evaluating blood lipid profiles, blood glucose control factors, protein expression of lipid metabolism, and insulin sensitivity improvement. Three groups of high-fat diet (HFD) induced obese C57BL/6 mice (n = 8) received treatment with low (5%; HFD + PO5%) or high (10%; HFD + PO10%) concentrations of P. oleracea powder for 12 weeks or no treatment (HFD) and were compared with each other and a fourth control group. Weight gain was reduced by 34% in the HFD + PO10% group compared to the HFD group. Moreover, the perirenal and epididymal fat contents in the HFD + PO10% group were 6.3-fold and 1.5-fold, respectively, lower than those in the HFD group. The atherogenic index (AI) and cardiac risk factor (CRF) results in the P. oleracea-treated groups were significantly lower than those in the HFD group. The homeostasis model assessment of insulin resistance (HOMA-IR) levels was lower in the HFD + PO10% group than in the HFD group. The protein expression levels of the proliferator-activated receptor (PPAR)-α, glucose transporter (GLUT) 4 and PPAR-γ were upregulated in the HFD + PO10% group compared to the HFD group. However, the protein expression levels of tumor necrosis factor (TNF)-α were lower in the P. oleracea-treated groups than in the HFD group. Our results demonstrate that P. oleracea powder could be effectively used to treat and prevent obesity and diabetes-associated diseases through suppression of weight gain and reduction in body fat and blood glucose levels.

Rice Bran Fermented with Kimchi-Derived Lactic Acid Bacteria Prevents Metabolic Complications in Mice on a High-Fat and -Cholesterol Diet

This aim of this study was to investigate the potential beneficial effects of rice bran powder, fermented by Weissella koreensis DB1 isolated from kimchi, to protect against obesity and dyslipidemia induced by a high-fat and high-cholesterol diet, in a mouse model. Male mice were fed a modified AIN-93M diet containing high fat/high-cholesterol (HFCD), or same diet supplemented with non-fermented rice bran powder (HFCD-RB) or fermented rice bran powder (HFCD-FRB) for 10 weeks. In the HFCD-FRB group, body weight, liver and white fat pads weights, triglyceride (TG), total cholesterol (TC), non-high-density lipopreotein cholesterol (non-HDL-C), insulin, glucose and leptine levels in serum, TG levels and the ratio of fat droplets in the liver, TG levels and fat cell size in adipose tissue were decreased, and (high-density lipopreotein cholesterol) HDL-C and adiponectin levels in serum were increased, compared with the HFCD group. The HFCD-FRB group had significantly lower CCAAT-enhancer-binding potein α (C/EBPα), sterol regulatory element-binding transcription protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl CoA carboxylase (ACC) gene expression when compared to the HFCD group. The anti-obesity and hypolipidemic effects were marginally greater in the HFCD-FRB group than in the HFCD-RB group. These results suggest that fermented rice bran powder by Weissella koreensis DB1 may have potential beneficial effects on the obesity-related abnormalities and the dysfunction of lipid metabolism.

Comparison of Antiobesity Effects Between Gochujangs Produced Using Different Koji Products and Tabasco Hot Sauce in Rats Fed a High-Fat Diet

In this study, we compared the antiobesity effects between gochujangs prepared using different koji products and Tabasco hot sauce in rats fed a high-fat diet (HFD). Male Sprague-Dawley rats were fed HFD containing four different types of 10% gochujang powder or 0.25% commercial Tabasco sauce powder for 8 weeks. The body weight gain, liver and epididymal and mesenteric fat pad weights, serum leptin levels, and lipogenesis-related mRNA levels of HFD-gochujang supplementation groups were significantly decreased compared with those of the HFD group. In addition, gochujang supplement significantly reduced adipocyte size; hepatic triglyceride and total cholesterol levels; the occurrence of fatty liver deposits and steatosis by inhibiting lipogenesis through downregulation of fatty acid synthase, acetly-CoA carboxylase, and glucose-6-phosphate-dehydrogenase. These effects were greater in the gochujang-supplemented groups than the Tabasco hot sauce-supplemented group. The gochujang prepared by nutritious giant embryo rice koji and soybean koji was most effective in terms of antiobesity effects, compared with the other tested gochujangs. In gochujangs, the antiobesity effects are mediated by high levels of secondary metabolites such as isoflavone, soyasaponin, capsaicin, and lysophosphatidylcholine. The current results indicated that the gochujang products have the potential to reduce fat accumulation and obesity.

Investigational therapies for hypercholesterolemia

INTRODUCTION

Cardiovascular morbidity and mortality are of increasing concern, not only to patients but also to the health care profession and service providers. The preventative benefit of treatment of dyslipidaemia is unquestioned but there is a large, so far unmet need to improve clinical outcome. There are exciting new discoveries of targets that may translate into improved clinical outcome. Areas covered: This review highlights some new pathways in cholesterol and triglyceride metabolism and examines new targets, new drugs and new molecules. The review includes the results of recent trials of relatively new drugs that have shown benefit in cardiovascular endpoint outcomes, drugs that have been licenced without endpoint trials yet available and new drugs that have not yet been licenced but have produced exciting results in animal studies and some in early phase 2 human studies. Expert opinion: The new areas that have been discovered as the cause of dyslipidaemia have opened up a host of new targets for new drugs including antisense RNA's, microRNA's and human monoclonal antibodies. The plethora of new targets and new drugs has made it an extraordinarily exciting time in the development of therapeutics to combat atherosclerosis.

Effects of lipids and lipoproteins on diabetic foot in people with type 2 diabetes mellitus: a meta-analysis

BACKGROUND

To conduct a meta-analysis of case-control studies to determine the effects of lipids and lipoproteins on morbidity of diabetic foot in adults with type 2 diabetes.

METHODS

We searched the PubMed and EMBASE to identify eligible studies. The Newcastle-Ottawa Quality Assessment Scale was used to determine the quality of selected studies. We assessed the strength of associations using standardized mean differences with 95% confidence intervals.

RESULTS

A total of 4 articles were found. Decreased HDL-cholesterol had a significant association with diabetic foot susceptibility in fixed-effects model, but no significant associations were found between diabetic foot and LDL-cholesterol, TC or TG levels.

CONCLUSIONS

Our results suggested that decreased HDL-cholesterol was associated with diabetic foot, so possible measures to prevent diabetic foot should include targeting increases in HDL-cholesterol.

High glucose, insulin and free fatty acid concentrations synergistically enhance perilipin 3 expression and lipid accumulation in macrophages

OBJECTIVE

Perilipin (PLIN) 3, an intracellular lipid droplet (LD)-associated protein, is implicated in foam cell formation. Since metabolic derangements found in metabolic syndrome, such as high serum levels of glucose, insulin and free fatty acids (FFAs), are major risk factors promoting atherosclerosis, we investigated whether PLIN3 expression is affected by glucose, insulin and oleic acid (OA) using RAW264.7 cells.

METHODS

Real-time PCR and Western blotting were performed to detect PLIN3 or PLIN2 expression. Oil-red O staining and Lipid Analysis were employed to measure cellular content of triacylglycerides (TAG) and cholesterol.

RESULTS

PLIN3 mRNA was stimulated by high glucose or insulin concentrations individually, but not by OA. A combination of any two factors did not enhance PLIN3 expression any more than that evoked by glucose alone at 24h. Interestingly, however, simultaneous addition of all three factors synergistically enhanced the PLIN3 expression. This synergistic effect was not apparent for PLIN2 mRNA expression. Inhibitors of Src family tyrosine kinase and/or phosphatidylinositol 3-kinase, both of which are activated by insulin and FFA signaling, partially suppressed PLIN3 expression induced by the combination of the three factors. While simultaneous addition of glucose, insulin and OA remarkably increased the cellular content of TAG and cholesterol, knocking-down of PLIN3 predominantly reduced TAG content.

CONCLUSIONS

These results indicate that PLIN3 expression is synergistically stimulated by high glucose, insulin and FFA concentrations, in parallel with TAG accumulation in macrophages. This finding raises new evidence of PLIN3 involvement in conversion of macrophages into foam cells.

Vitellogenin recognizes cell damage through membrane binding and shields living cells from reactive oxygen species

Large lipid transfer proteins are involved in lipid transportation and diverse other molecular processes. These serum proteins include vitellogenins, which are egg yolk precursors and pathogen pattern recognition receptors, and apolipoprotein B, which is an anti-inflammatory cholesterol carrier. In the honey bee, vitellogenin acts as an antioxidant, and elevated vitellogenin titer is linked to prolonged life span in this animal. Here, we show that vitellogenin has cell and membrane binding activity and that it binds preferentially to dead and damaged cells. Vitellogenin binds directly to phosphatidylcholine liposomes and with higher affinity to liposomes containing phosphatidylserine, a lipid of the inner leaflet of cell membranes that is exposed in damaged cells. Vitellogenin binding to live cells, furthermore, improves cell oxidative stress tolerance. This study can shed more light on why large lipid transfer proteins have a well conserved α-helical domain, because we locate the lipid bilayer-binding ability of vitellogenin largely to this region. We suggest that recognition of cell damage and oxidation shield properties are two mechanisms that allow vitellogenin to extend honey bee life span.

PKCβ promotes vascular inflammation and acceleration of atherosclerosis in diabetic ApoE null mice

OBJECTIVE

Subjects with diabetes mellitus are at high risk for developing atherosclerosis through a variety of mechanisms. Because the metabolism of glucose results in production of activators of protein kinase C (PKC)β, it was logical to investigate the role of PKCβ in modulation of atherosclerosis in diabetes mellitus.

APPROACH AND RESULTS

ApoE(-/-) and PKCβ(-/-)/ApoE(-/-) mice were rendered diabetic with streptozotocin. Quantification of atherosclerosis, gene expression profiling, or analysis of signaling molecules was performed on aortic sinus or aortas from diabetic mice. Diabetes mellitus-accelerated atherosclerosis increased the level of phosphorylated extracellular signal-regulated kinase 1/2 and Jun-N-terminus kinase mitogen-activated protein kinases and augmented vascular expression of inflammatory mediators, as well as increased monocyte/macrophage infiltration and CD11c(+) cells accumulation in diabetic ApoE(-/-) mice, processes that were diminished in diabetic PKCβ(-/-)/ApoE(-/-) mice. In addition, pharmacological inhibition of PKCβ reduced atherosclerotic lesion size in diabetic ApoE(-/-) mice. In vitro, the inhibitors of PKCβ and extracellular signal-regulated kinase 1/2, as well as small interfering RNA to Egr-1, significantly decreased high-glucose-induced expression of CD11c (integrin, alpha X 9 complement component 3 receptor 4 subunit]), chemokine (C-C motif) ligand 2, and interleukin-1β in U937 macrophages.

CONCLUSIONS

These data link enhanced activation of PKCβ to accelerated diabetic atherosclerosis via a mechanism that includes modulation of gene transcription and signal transduction in the vascular wall, processes that contribute to acceleration of vascular inflammation and atherosclerosis in diabetes mellitus. Our results uncover a novel role for PKCβ in modulating CD11c expression and inflammatory response of macrophages in the development of diabetic atherosclerosis. These findings support PKCβ activation as a potential therapeutic target for prevention and treatment of diabetic atherosclerosis.

A gene variation (rs12691) in the CCAT/enhancer binding protein α modulates glucose metabolism in metabolic syndrome

BACKGROUND AND AIMS

CCAAT/enhancer-binding protein alpha (CEBPA) is a transcription factor involved in adipogenesis and energy homeostasis. Caloric restriction reduces CEBPA protein expression in patients with metabolic syndrome (MetS). A previous report linked rs12691 SNP in CEBPA to altered concentration of fasting triglycerides. Our objective was to assess the effects of rs12691 in glucose metabolism in Metabolic Syndrome (MetS) patients.

METHODS AND RESULTS

Glucose metabolism was assessed by static (glucose, insulin, adiponectin, leptin and resistin plasma concentrations) and dynamic (disposition index, insulin sensitivity index, HOMA-IR and acute insulin response to glucose) indices, performed at baseline and after 12 weeks of 4 dietary interventions (high saturated fatty acid (SFA), high monounsaturated fatty acid (MUFA), low-fat and low-fat-high-n3 polyunsaturated fatty acid (PUFA)) in 486 subjects with MetS. Carriers of the minor A allele of rs12691 had altered disposition index (p = 0.0003), lower acute insulin response (p = 0.005) and a lower insulin sensitivity index (p = 0.025) indicating a lower insulin sensitivity and a lower insulin secretion, at baseline and at the end of the diets. Furthermore, A allele carriers displayed lower HDL concentration.

CONCLUSION

The presence of the A allele of rs12691 influences glucose metabolism of MetS patients.

Lipid metabolism after an oral fat test meal is affected by age-associated features of metabolic syndrome, but not by age

OBJECTIVE

Postprandial lipemia influences the development of atherosclerosis. Age has been defined as a regulating factor of the extent of postprandial lipemia, but its independence of other age-associated phenotypic features, such as metabolic syndrome, has not been fully elucidated.

METHODS

To investigate if age is an independent factor influencing postprandial lipemia, we compared the lipemic response to a rich fatty meal (60% fat) of 88 healthy young men (<30 years old) and 97 older participants (77 metabolic syndrome patients aged > 40; and 20 healthy people > 65) (all ApoE3/E3), at fasting state and at 2nd and 4th postprandial hours.

RESULTS

We didn't find differences between the healthy young men and the healthy elderly. The metabolic syndrome patients displayed a higher postprandial TG area below the curve than the other two cohorts p < 0.001. ANOVA for repeated measurements confirmed that these differences were significant at every time-point (fasting, 2 h and 4 h). Concomitant higher responses for Large and Small TRL-carried TG and Chol were found in these metabolic syndrome patients. Interestingly, the most significant differences were found for Small-TRL-carried particles, which suggest that this fact may be mainly due to impaired lipid clearance.

CONCLUSION

Metabolic syndrome may account for the differences in postprandial lipemia that have been attributed to age. In our study, there were no significant differences in postprandial lipemia between a young population (mean age 22.6 years) and a healthy people >65 years one (67.2 years) without metabolic syndrome.

Differential roles of breakfast only (one meal per day) and a bigger breakfast with a small dinner (two meals per day) in mice fed a high-fat diet with regard to induced obesity and lipid metabolism

Background

Recent studies on humans and rodents have suggested that the timing of food intake plays an important role in circadian regulation and metabolic health. Consumption of high-fat foods during the inactive period or at the end of the awake period results in weight gain and metabolic syndrome in rodents. However, the distinct effects of breakfast size and the breakfast/dinner size ratio on metabolic health have not yet been fully examined in mice.

Methods

We examined whether the parameters of metabolic syndrome were differentially affected in mice that consumed a large meal at the beginning of the awake period (breakfast; one meal group) and a relatively smaller meal at end of the awake period (dinner; two meals group). The mice of each group were provided equal food volume per day.

Results

Mice on one meal exhibited an increase in body weight gain, hyperinsulinemia, hyperleptinemia, and a decrease of gene expression associated with β-oxidation in adipose tissue and liver compared with those on two meals. The circadian expression pattern of the Clock gene in mice on one meal was disturbed compared with those on two meals.

Conclusions

In conclusion, a bigger breakfast with a smaller dinner (two meals per day) but not breakfast only (one meal per day) helps control body weight and fat accumulation in mice on a high-fat meals schedule. The findings of this study suggest that dietary recommendations for weight reduction and/or maintenance should include information on the timing and quantity of dietary intake.

Diet, commensals and the intestine as sources of pathogen-associated molecular patterns in atherosclerosis, type 2 diabetes and non-alcoholic fatty liver disease

Stimulation of the innate immune receptors Toll-like receptor (TLR)-2 and TLR4 has been shown to promote the development of a variety of diseases involving dysregulated metabolism, including atherosclerosis, type 2 diabetes and non-alcoholic fatty liver disease. However, the origin and nature of the agents responsible for stimulating TLR2 or TLR4 signalling in these conditions remain to be clearly identified. This review summarises the evidence supporting the proposal that 'pathogen-associated molecular patterns' (PAMPs) derived from dietary and commensal sources may contribute to the chronic inflammatory processes that underpin the development of these diseases via stimulation of TLR2 and TLR4. In particular, insights gained from recent studies employing TLR-transfectant based bioassays to quantify the abundance of PAMPs in foodstuffs and specific commensal compartments are discussed. Finally, the major mechanisms by which TLR-stimulants may gain access to the circulation to promote systemic low-grade inflammation are considered.