The Role of Advanced Glycation End Products on Dyslipidemia.

Disorders of lipoprotein metabolism and glucose homeostasis are common consequences of insulin resistance and usually co-segregate in patients with metabolic syndrome and type 2 diabetes mellitus (DM). Insulin-resistant subjects are characterized by atherogenic dyslipidemia, a specific lipid pattern which includes hypertriglyceridemia, reduced high-density lipoprotein cholesterol level, and increased proportion of small, dense low-density lipoprotein (LDL). Chronic hyperglycemia favors the processes of non-enzymatic glycation, leading to the increased production of advanced glycation end products (AGEs). Apart from direct harmful effects, AGEs are also potent inducers of oxidative stress and inflammation. In addition, increased AGEs' production may induce further qualitative modifications of small, dense LDL particles, converting them to glycated LDLs. These particles are even more atherogenic and may confer an increased cardiovascular risk. In this narrative review, we summarize the available evidence of the pathophysiological role and clinical importance of circulating AGEs and glycated LDLs in patients with dyslipidemia, particularly those with DM and related complications. In addition, we discuss recent advances and the issues that should be improved regarding laboratory assessment of AGEs and glycated LDLs, as well as the possibilities for their therapeutic modulation.

Downregulation of mapk/mak/mrk overlapping kinase 1 in peripheral blood mononuclear cells of pediatric patients with type 1 diabetes mellitus.

Background: Type 1 diabetes mellitus (T1DM) is one of the most common endocrine diseases in children. T-cell autoreactivity toward b-cells is controlled by significant changes in metabolism of T cells. Mammalian target of rapamycin (mTOR) is an important intracellular regulator of metabolism and cell growth. MAPK/MAK/MRK overlapping kinase 1 (MOK1) is one of the less known regulators of mTOR. We sought to investigate if MOK1 and mTOR mRNA levels in peripheral blood mononuclear cells (PBMCs) of T1DM pediatric patients are different compared to healthy subjects. Methods: This study included 172 adolescents with T1DM and 36 healthy adolescent volunteers designated for control group (CG). MOK1 and mTOR mRNA levels were determined in PBMCs by qPCR. Results: T1DM patients have significant downregulation of MOK1 mRNA levels in PBMCs compared CG (P=0.018), while there was no significant difference in mTOR mRNA levels (P=0.891). Furthermore, in T1DM patients, MOK1 significantly correlated with age, triglycerides and mTOR, while mTOR correlated significantly with BMI and systolic blood pressure. Overweight T1DM subjects had significantly lower MOK1 (P=0.034) and mTOR (P=0.017) mRNA levels, together with significantly higher levels of systolic blood pressure (P<0.001), total cholesterol (P=0.001), LDL-cholesterol (P=0.001) and CRP (P<0.001). Multi - variate analysis showed that MOK1 was independently negatively associated with T1DM when adjusted for sex, age, HDL-C and CRP (OR=0.417 (95%CI: 0.175-0.997), p=0.049). Conclusions: Our study demonstrated for the first time that T1DM is associated with MOK1 downregulation. In addition, downregulation of both mTOR and MOK1 gene expressions was associated with cardiovascular risk factors in overweight T1DM patients.

Transforming Growth Factor-ß1 and Receptor for Advanced Glycation End Products Gene Expression and Protein Levels in Adolescents with Type 1 iabetes Mellitus

Objective: Type 1 diabetes (T1D) mellitus is one of the most frequent autoimmune diseases in childhood. Chronic complications are the main causes of cardiovascular morbidity and mortality in T1D. Although interactions between advanced glycation end products (AGE) and their receptors (RAGE) and transforming growth factor-ß1 (TGF-ß1) are implicated in development and progression of diabetic microand macro-vascular complications, they also have important roles in immune system regulation. Methods: Blood samples were obtained from 156 adolescents with T1D and 80 apparently healthy controls. T1D patients diagnosed with any other autoimmune disease and receiving any kind of drugs except insulin therapy were excluded from this study. Exclusion criteria for controls were positive family history of T1D and drugs/supplements application. TGF-ß1 and transmembrane full-length RAGE (flRAGE) messenger ribonucleic acid (mRNA) levels in peripheral blood mononuclear cells (PBMC) were obtained by quantitative polymerase chain reaction (qPCR) method. Circulating levels of biochemical markers, TGF-ß1 and soluble RAGE (sRAGE) levels were also determined. Results: TGF-ß1 and flRAGE mRNA levels were significantly higher in controls compared to patients (p<0.001, for both). However, TGF-ß1 and sRAGE levels were higher in patients than controls (p<0.001, for both). There were significant independent associations of all mRNA and protein levels with T1D. TGF-ß1 mRNA was the only marker independently negatively associated with urinary albumin excretion rate in T1D adolescents (p=0.005). Conclusion: Our results indicated gene expression downregulation of TGF-ß1 and flRAGE in PBMC of T1D adolescents. TGF-ß1 mRNA downregulation may be useful for predicting early elevation of urinary albumin excretion rate.

Heparin-binding epidermal growth factor (EGF)-like growth factor in pediatric patients with type 1 diabetes mellitus.

Heparin-binding EGF-like growth factor (HB-EGF) is involved in atherosclerosis progression. We investigated association between plasma HB-EGF levels and lipid, oxidative stress and inflammatory biomarkers in pediatric patients with type 1 diabetes mellitus (T1DM). Levels of HB-EGF, high-sensitive C-reactive protein (hsCRP), prooxidant-antioxidant balance (PAB), total antioxidant status (TAS), oxidized low-density lipoproteins (oxLDL), metabolic control and serum lipid parameters and paraoxonase 1 (PON1) activity were determined in 74 patients and 40 controls. In comparison to controls, patients had significantly higher levels (p < 0.01) of HB-EGF, hsCRP, PAB and oxLDL particles (p < 0.001), but lower levels of TAS and PON1 activity. In T1DM group, HB-EFG levels were positively associated with hsCRP, PAB and oxLDL levels. hsCRP and oxLDL levels were independent predictors of HB-EGF concentration. We demonstrated that oxidative modifications of LDL particles and low-grade inflammation are main determinants of increased plasma HB-EGF levels, which indicates an interactive role of oxidative stress, dyslipidemia and inflammation.

Factors associated with oxidative stress status in pediatric patients with type 1 diabetes mellitus.

Background Oxidative stress is implicated in both, the onset and the progression of type 1 diabetes mellitus (T1DM). There is accumulated evidence of increased biomarkers of oxidative stress in newly diagnosed, T1DM patients without complications, and in those with advanced disease. In this cross-sectional study, we investigated factors affecting oxidative stress status in pediatric patients with T1DM. Methods Advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), total sulfhydryl (SH) groups, and superoxide dismutase (SOD) activity were determined in 170 children and adolescents with T1DM. Principal component analysis was used to investigate clustering of clinical and laboratory variables associated with elevated oxidative stress and reduced antioxidative defense biomarkers. Results Factor analysis extracted five factors, interpreted as (1) "weight status factor" including age, BMI, waist and hip circumferences; (2) "proatherogenic factor" that included LDL-cholesterol, non-HDL-cholesterol, and triglycerides; (3) "metabolic control factor" including glucose and HbA1c; (4) "renal marker factor" with positive loading of urinary albumin excretion rate and negative loading of GFR; and (5) "antiatherogenic factor" that included HDL-cholesterol. High AOPP levels were independently predicted by "proatherogenic" (OR: 2.32; 95% CI: 1.44-3.71; p < 0.001), "metabolic control" (OR: 2.24; 95% CI: 1.35-3.73; p < 0.01), and "renal marker" (OR: 1.65; 95% CI: 1.03-2.65; p < 0.05) factors. "Renal marker factor" was a significant predictor of PAB (OR: 0.52; 95% CI: 0.34-0.81; p < 0.01). Regarding antioxidative defense markers, reduced SH groups were predicted by "proatherogenic factor" (OR: 0.56; 95% CI: 0.34-0.94; p < 0.05), while "weight status factor" predicted lower SOD activity (OR: 1.66; 95% CI: 1.03-2.67; p < 0.05). Conclusions Cardiometabolic risk factors and renal function are associated with oxidative stress in pediatric T1DM patients.

Association between proprotein convertase subtilisin/kexin 9 (PCSK9) and lipoprotein subclasses in children with type 1 diabetes mellitus: Effects of glycemic control.

BACKGROUND AND AIMS: Dyslipidemia in type 1 diabetes mellitus (T1DM) is characterised by altered distributions of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subclasses. Recent studies suggested that proprotein convertase subtilisin/kexin 9 (PCSK9) may contribute to the development of dyslipidemia in T1DM. In this cross-sectional study, we investigated the association between PCSK9 and lipoprotein subclasses in young T1DM patients, with respect to glycemic control. METHODS: Plasma PCSK9 and lipoprotein subclasses were determined in 207 patients with T1DM (106 boys and 101 girls), aged 13.9 ±â€¯3.0 years and treated by intensive insulin therapy. RESULTS: Plasma PCSK9 levels significantly increased with worsening of glycemic control (p < 0.001). T1DM patients with poor glucoregulation had the highest proportion of small, dense LDL (sdLDL) and smaller HDL particles, as well. PCSK9 was positively associated with markers of glucose homeostasis and serum lipid parameters only in patients with suboptimal/poor glucoregulation. In well-controlled T1DM, plasma PCSK9 level was inversely associated with a relative proportion of sdLDL particles (p < 0.01) and this association remained significant in multivariate analysis. In T1DM patients with suboptimal/poor glycemic control, PCSK9 was positively associated with the proportion of the smallest HDL3c particles (p < 0.001), but negatively with HDL size (p < 0.05). CONCLUSIONS: The extent of achieved metabolic control modifies the association between PCSK9 and lipoprotein subclasses in T1DM. Further investigations are needed to reveal whether the observed effects of glycemic control on PCSK9 and sdLDL levels have causal consequences on CVD risk in young patients with T1DM.

The association of hs-CRP and fibrinogen with anthropometric and lipid parameters in non-obese adolescent girls with polycystic ovary syndrome.

Background The aim of the study was to evaluate high-sensitivity C-reactive protein (hs-CRP) and fibrinogen in non-obese normoinsulinemic adolescent girls with polycystic ovary syndrome (PCOS) and their relationship with anthropometric and lipid parameters. Methods The study comprised a total of 26 adolescent girls newly diagnosed with PCOS and 12 healthy controls with regular ovulatory menstrual cycles. The concentration of hs-CRP, fibrinogen, anthropometric measurements, and biochemical and hormonal testing were assessed. Results PCOS adolescent girls had significantly higher levels of hs-CRP and fibrinogen compared to healthy controls. In univariate regression analysis, statistically significant associations of hs-CRP and fibrinogen levels of PCOS patients have been shown with body mass index (BMI), waist circumference (WC), hip circumference (HC) and low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio, while hs-CRP levels were also associated with cholesterol and LDL. In the multivariate regression model, we found that hs-CRP levels were predicted by BMI (ß=0.541, p<0.001) and LDL (ß=0.507, p=0.014), while fibrinogen levels were predicted by BMI (ß=0.449, p=0.004). Conclusions We have shown an association of proinflammatory indices hs-CRP and fibrinogen with anthropometric and lipid parameters of adolescent women with PCOS. The inflammatory markers might be useful in monitoring normal-weight adolescent women with PCOS in an effort to timely prevent unfavorable changes in body mass and lipid profile.

Effects of co-existing autoimmune diseases on serum lipids and lipoprotein subclasses profile in paediatric patients with type 1 diabetes mellitus.

OBJECTIVE: Paediatric patients with type 1 diabetes mellitus (T1DM) frequently develop other autoimmune disorders; most commonly autoimmune thyroiditis (ATD) and celiac disease (CD). In this study we evaluated whether co-existing autoimmune diseases had significant impact on lipid and lipoprotein subclasses, as known cardiovascular risk factors in T1DM. DESIGN AND METHODS: Study included 201 subjects with T1DM (14.1 ±â€¯2.9 years) and 141 age- and gender-matched controls. ATD was presented in 30 and CD in 15 T1DM patients. Serum lipid parameters were determined by routine laboratory methods and plasma low-density (LDL) and high-density lipoprotein (HDL) subclasses by gradient-gel electrophoresis method. RESULTS: Both groups of T1DM patients with concomitant autoimmune disease had significantly lower HDL-C levels (P < 0.05) than the patients with T1DM only, but comparable to control group (P = 0.436). T1DM patients had significantly higher (P < 0.001) proportion of small HDL subclasses than controls. Mean value of atherosclerosis index in patients with T1DM + CD was the highest (1.75 ±â€¯0.86) and it was significantly higher than the index in patients with T1DM only (1.33 ±â€¯0.51; P < 0.05). LDL size did not differ between the groups of T1DM patients and control group (P = 0.619). The size of HDL particles was significantly reduced (P < 0.05) in the groups with associated autoimmune diseases. The patients with co-existing autoimmune diseases had higher risk of low HDL-C level (OR: 2.96; P < 0.05). CONCLUSIONS: The results have shown significant impact of co-existing autoimmune diseases on lipid profile in patients with T1DM. The most prominent changes were found in HDL lipoprotein characteristics in T1DM + CD group.

The usefulness of advanced lipid and oxidative stress testing for diagnosis and management of low HDL-cholesterol phenotype: A case report.

OBJECTIVE: Plasma high-density lipoprotein cholesterol (HDL-C) level is a strong inverse predictor of cardiovascular disease (CVD) development. Tangier disease, a consequence of mutations in the ATP binding cassette transporter 1 (ABCA1) gene, is associated with very low HDL-C levels. Still, the relationship between Tangier disease and CVD is not always evident. The study investigates usefulness of lipoprotein subfractions, oxidative stress and paraoxonase 1 (PON1) status assessment for evaluation and management of patient with low HDL-C phenotype. PATIENT AND METHODS: A 12-year-old boy was hospitalised due to hypertension. Laboratory evaluation revealed low HDL-C level, and subsequent molecular diagnostic confirmed Tangier disease. Lipoprotein subfractions were assessed by gradient-gel electrophoresis. Oxidative stress status was estimated by measuring total antioxidative status, total oxidative status, prooxidative-antioxidative balance, malondialdehyde and advanced oxidation protein products levels. Activity of paraoxonase 1 in serum and its distribution within HDL subclasses was also determined (ten healthy boys aged 13.1±3.4years served as the reference group). RESULTS: Analysis of oxidative stress status biomarkers revealed a state of prolonged prooxidants activity. In turn, serum PON1 activity was substantially reduced. The majority of PON1 activity was present on HDL 2 particles. CONCLUSION: Impaired antioxidative potential of HDL may point toward hidden cardiovascular risk in isolated low HDL-phenotype.

N-terminal pro-brain natriuretic peptide in the assessment of respiratory distress in term neonates.

BACKGROUND: N-terminal pro-brain natriuretic peptide (NT-proBNP) is used as a biomarker to differentiate congestive heart failure from lung disease in adults and children. The clinical significance of its use in term neonates has not yet been extensively studied. METHODS: NT-proBNP level was measured in 62 term neonates admitted for respiratory distress (RD): 38 with congenital heart disease (CHD) and 24 with pulmonary disease. The control group consisted of 28 healthy neonates. Findings of auscultation, chest radiography, Silverman-Anderson score and echocardiography were recorded for each patient. Blood samples for measuring NT-proBNP were collected on admission, when blood sampling was indicated for the clinical management of the newborn. RESULTS: In the control group NT-proBNP was significantly higher during the first week of life compared to the rest of the neonatal period (P < 0.001). The RD group, regardless of etiology, had significantly higher NT-proBNP than the control group (P < 0.001). Neonates with more severe RD had significantly higher NT-proBNP (P = 0.002). No significant difference was found between the RD group with CHD and those with pulmonary disease. Neonates with CHD and myocardial hypocontractility had significantly higher NT-proBNP than those with normal contractility (P = 0.022). CONCLUSION: Term neonates with RD have significantly higher NT-proBNP than healthy neonates. A single measurement of NT-proBNP level cannot be used as the sole biomarker for distinguishing between cardiac and pulmonary cause of RD in term neonates.