Endoplasmic reticulum stress and Nrf2 repression in circulating cells of type 2 diabetic patients without the recommended glycemic goals

Endoplasmic reticulum (ER) stress plays a role in the pathogenesis of type 2 diabetes mellitus (T2DM), with activation of the unfolded protein response (UPR) and ER apoptosis in \u3b2-cells. The aim of the study is investigating the role of the prolonged glycemic, inflammatory, and oxidative impairment as possible UPR and ER apoptosis inductors in triggering the ER stress response and the protective nuclear erythroid-related factor 2 (Nrf2)/antioxidant-related element (ARE) activation in peripheral blood mononuclear cells (PBMC) of T2DM patients without glycemic target. Oxidative stress markers (oxidation product of phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine [oxPAPC], and malondialdehyde [MDA]), the UPR and ER apoptosis, the activation of the pro-inflammatory nuclear factor-kappa B (NF-kB) with its inhibitory protein inhibitor-kB\u3b1, and the expression of the protective Nrf2 and heme oxygenase-1 (HO-1) were evaluated in PBMC of 15 T2DM patients and 15 healthy controls (C). OxPAPC concentrations (in PBMC and plasma), MDA levels (in plasma), the expressions of the glucose-regulated protein 78 kDa (or BiP) as representative of UPR, and of the CCAAT/enhancer-binding protein homologous protein as representative of ER apoptosis were significantly higher (p < 0.01) in T2DM with respect to C. IkB\u3b1 expression was significantly lower (p < 0.01) in T2DM as well as Nrf2 and HO-1. In vitro experiments demonstrated that hyperglycemic conditions, if prolonged, were NF-kB inductors, without a corresponding Nrf2/ARE response. In PBMC of T2DM without glycemic target achievement, there is an activation of the UPR and of the ER apoptosis, which may be related to the chronic exposure to hyperglycemia, to the augmented inflammation, and to the augmented oxidative stress, without a corresponding Nrf2/ARE defense activation

Studio ecocolordoppler della stenosi carotidea. Metodi a confronto

Introduzione. La stenosi aterosclerotica della carotide rappresenta la patologia clinicamente pi\uf9 rilevante nell'ambito dell'insufficienza cerebrovascolare. Essa \ue8 responsabile del 35,80/0 degli ictus ischemici (1). L'ictus rappresenta in Italia la terza causa di morte e la prima causa di invalidit\ue0 (2). Scopo. In questo lavoro si \ue8 voluto testare le capacit\ue0 del Duplex-Scanner di analizzare la placca carotidea; l'end point \ue8 stato duplice. TI primo \ue8 un confronto retrospettivo dell'imaging ecografico (B-Mode con color/power doppler) con i dati dinamici di velocimetria nello studio della stenosi carotidea. TI secondo \ue8 una valutazione prospettica della capacit\ue0 del Duplex di effettuare una corretta caratterizzazione strutturale della placca ateromasica. Materiali e Metodi. Dal primo gennaio 2008 al 28 febbraio 20Il sono stati effettuati presso il nostro ambulatorio 2786 esami ECD, di cui 536 sono stati definiti come patologici (stenosi = 60% e VPS > 120 cm/sec). I pazienti le cui lesioni rispondevano a questi criteri sono stati sottoposti ad un secondo esame duplex eseguito da un operatore esperto: sono stati confermati come patologici 498 pazienti e di questi 78 sono stati indirizzati all'intervento chirurgico. In 17 casi abbiamo ottenuto la valutazione anatomo patologica della placca. Risultati. Nel primo end point abbiamo che per i valori di cut-off di VPS > 120 cml sec la percentuale di concordanza tra dati morfologici e i dati velocimetrici \ue8 stata dell'84,6%. TI 15,4% dei pazienti portatori di stenosi =60% ha quindi una velocimetria non concordante con tale stenosi (cut-off 120 cm/sec). TI secondo end point mostra come delle 17 placche esaminate in laboratorio le lO definite ecograficamente stabili erano in realt\ue0 9 e le 7 descritte all'ECD come instabili sono risultate essere 8

Antioxidants inhibit the expression of intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 induced by oxidized LDL on human umbilical vein endothelial cells.

The oxidative modification of low density lipoprotein (LDL) and the endothelial expression of adhesion molecules are key events in the pathogenesis of atherosclerosis. In this study we evaluated the effect of oxidized LDL on the expression of intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM- 1), and E-selectin on human umbilical vein endothelial cells (HUVECs). The hypothesis that oxidized LDL functions as a prooxidant signal was also evaluated, by studying the effect of different radical-scavenging antioxidants on expression of adhesion molecules. LDL was oxidized by using Cu-2+, HUVECs or phospholipase A-2 (PLA-2)/soybean lipoxygenase (SLO), the degree of oxidation being measured as thiobarbituric acid-reactive substances (TBARS) and conjugated dienes (CD). Exposure of 200 mu-g/ml of native LDL to 1 mu Cu-2+ HUVECs and to PLA-2/ SLO resulted in four- to fivefold higher levels of TBARS and CD than in native LDL. Cu-2+- (1 mu-M), HUVEC-, and PLA-2/SLO-oxidized LDL caused a dose-dependent, significant increase of ICAM-1 and VCAM-1 (p lt .01). The expression of E-selectin did not change. LDL oxidized with a 2.5 and 5 mu-M Cu-2+ did not increase ICAM-1 and VCAM-1 significantly. Both the CU-2+- and HUVEC-oxidized LDL, subjected to dialysis and ultrafiltration, induced ICAM-1 and VCAM-1 expression. After incubation with the ultrafiltrate, the expression of ICAM-1 and VCAM-1 was not significantly different from that obtained with native LDL. LDL pretreated with different antioxidants (vitamin E and probucol) and subjected to oxidation by Cu-2+ and HUVECs induced a significantly lower expression of ICAM-1 and VCAM-1 than nonloaded LDL (p lt .01). The pretreatment of HUVECs with vitamin E and probucol significantly reduced the expression of VCAM-1 on HUVECs induced by oxidized LDL (p lt .01); the effect on ICAM-1 was much less evident. In conclusion, oxidized LDL can induce the expression of different adhesion molecules on HUVECs; this induction can be prevented by pretreating either the LDL or the cells with radical-scavenging antioxidant

Oxidized low-density lipoprotein increases the production of intracellular reactive oxygen species in endothelial cells: inhibitory effect of lacidipine.

OBJECTIVE: The mechanisms by which oxidized low-density lipoprotein (ox-LDL) induces the expression of adhesion molecules on endothelial cells (HUVECs) are still not clear. The signal transduction pathways for these binding molecules include the translocation of the transcription factor NF-kB and the intracellular reactive oxygen species (ROS) are said to play a key role in this process. Aim of this study was (1) to evaluate the effect of ox-LDL on intracellular production of ROS in culture of HUVECs; (2) to evaluate if the intracellular increase of ROS induced by ox-LDL is mediated by the binding to a specific endothelial receptor; (3) to ascertain if lacidipine can decrease ox-LDL-induced ROS production in HUVECs. METHODS: Five microM Cu2+ ox-LDL were incubated with HUVECs for 5 min. 2',7'-Dichlorofluorescein (DCF) as an expression of intracellular ROS production, was measured by flow cytometry. RESULTS: ox-LDL induced a significant dose-dependent increase in DCF production (P < 0.001) through the binding to a specific receptor. The preincubation of HUVECs with radical scavengers compounds and lacidipine significantly reduced (P < 0.001) the ox-LDL-induced DCF production. CONCLUSIONS: ox-LDL increased the intracellular formation of ROS through the ligation to a specific endothelial receptor. Preincubation of HUVECs with lacidipine, a calcium antagonist with antioxidant properties, significantly reduced the intracellular ROS formation induced by ox-LDL. We propose that the effect of lacidipine on adhesion molecule expression and on NF-kB activation can be explained by its effect on intracellular ROS formation

E-Selectin plasma concentration is influenced by glycaemic control in NIDDM patients: Possible role of oxidative stress

Although elevated levels of soluble E-selectin and intercellular cell adhesion molecules-1 (ICAM-1) have been reported in non-insulin-dependent diabetes mellitus (NIDDM), it is not clear by what mechanism this elevation occurs and whether or not it is related to glycaemic control. In this study we analyse: 1) the relation of glycaemic control with the concentrations of E-selectin, vascular cell adhesion molecules-1 (VCAM-1) and ICAM-1 in NIDDM patients; 2) whether metabolic control can affect the oxidative stress (as measured by plasma hydroperoxide concentration and susceptibility of LDL to in vitro oxidation) and hence the adhesion molecule plasma concentrations. Thirty-four (19 males and 15 females) poorly controlled NIDDM patients were studied. All parameters were evaluated at the beginning of the study and after 90 days of dietary and pharmacological treatment. The treatment decreased HbA-1C (p lt 0.001), E-selectin (p lt 0.001), plasma hydroperoxides (p lt 0.003) and the susceptibility of LDL to in vitro oxidation (lag phase) (p lt 0.0001). Before treatment HbA-1C, lag phase and lipid hydroperoxides correlated with E-selectin plasma concentration (r = 0.51, -0.57 and 0.54, respectively, p lt 0.01). There was also a correlation between HbA-1C and lag phase (p lt 0.01) and between HbA-1C and lipid hydroperoxides (p lt 0.01). In addition, the variations of HbA-1C, lag phase and lipid hydroperoxide values correlated with those for E-selectin concentration after 90 days' treatment (r = 0.54, -0.64 and 0.61, respectively, p lt 0.01). In multiple linear correlation analysis, however, the partial correlation coefficients of HbA-1C (basal and variations) with E-selectin concentration (basal and variations) fell to non-significant values (r = 0.12 and 0.25, respectively) when LDL lag phase and plasma hydroperoxides were kept constant. The results indicate that the improvement of metabolic control in NIDDM patients is associated with a decrease of E-selectin plasma levels; they also suggest that glycaemic control per se is not directly implicated in determining E-selectin plasma concentration; glycaemic control could affect E-selectin concentration through its effect on oxidative stress

Modified LDL in the pathogenesis of atherosclerosis: role of nutrition

This book addresses the role of lipids in nutrition. Since modified LDL plays a key role in the pathogenesis of atherosclerosis, in this chapter we explore the effects of nutrition on LDL oxidation

Increased susceptibility of LDL to in vitro oxidation in patients on maintenance hemodialysis: effects of fish oil and vitamin E administration.

Oxidized low-density lipoproteins (LDL) play an important role in the pathogenesis of atherosclerosis. An increased sensitivity of red blood cell membranes to lipid peroxidation has been previously demonstrated in patients with chronic renal failure, suggesting that the antioxidant defence of lipoproteins might be impaired. Fish oil supplementation has been proposed in dialysis patients, but it is still unclear if the positive effects of fish oil depend only on its polyunsaturated fatty acid content or on other factors, such as the usually added antioxidants. Moreover, the increased concentration of highly peroxidable n-3 polyunsaturated fatty acids induced by fish oil in LDL particles could favour LDL oxidation and possibly the development of atherosclerosis. The present study was designed to evaluate the susceptibility of LDL to in vitro oxidation (lag phase) and the rate of lipid peroxidation (propagation phase) by fluorescence development during copper exposure in 14 hemodialysis patients. A further aim was to compare the effects on lipid metabolism and LDL oxidation of fish oil supplementation (20 ml containing vitamin E 20 IU as antioxidant) for 30 days and of vitamin E administration (50 IU) for another 30 days. The length of the lag phase and vitamin E concentration were significantly reduced (p lt 0.01) in hemodialysis patients and increased significantly (p lt 0.01) after administration of both fish oil and vitamin E. Fish oil supplementation also reduced plasma lipids significantly (p lt 0.01) and increased the propagation phase (p lt 0.01). Our results demonstrate that the susceptibility of LDL to oxidation is enhanced in hemodialysis patients, suggesting a possible relationship between excessive LDL peroxidation and accelerated atherosclerosis. The increased susceptibility of LDL to in vitro oxidation can be explained, at least partially, by a reduced LDL vitamin E concentration. Since fish oil increased the lag phase to the same extent as vitamin E supplementation, the positive effect of fish oil could be partly explained by its antioxidant content