Correlation between total nitrite/nitrate concentrations and monoamine oxidase (types A and B) and semicarbazide-sensitive amine oxidase enzymatic activities in human mesenteric arteries from non-diabetic and type 2 diabetic patients

The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: Km (r = 0.612, P = 0.034) and Vmax (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: Km (r = -0.625, P = 0.029) and Vmax (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress.

Clinical features of patients with type 2 diabetes mellitus and hepatitis C infection

The objective of the present cross-sectional study was to assess the prevalence and the clinical and laboratory features of hepatitis C virus (HCV)-positive patients with type 2 diabetes mellitus (DM) attending either an outpatient clinic or hemodialysis units. Serologic-HCV testing was performed in 489 type 2 DM patients (303 outpatients and 186 on dialysis). A structured assessment of clinical, laboratory and DM-related complications was performed and the patients were then compared according to HCV infection status. Mean patient age was 60 years; HCV positivity (HCV+) was observed in 39 of 303 (12.9%) outpatients and in 34 of 186 (18.7%) dialysis patients. Among HCV+ patients, 32 were men (43.8%). HCV+ patients had higher serum levels of aspartate aminotransferase (0.90 ± 0.83 vs 0.35 ± 0.13 µKat/L), alanine aminotransferase (0.88 ± 0.93 vs 0.38 ± 0.19 µKat/L), gamma-glutamyl transferase (1.57 ± 2.52 vs 0.62 ± 0.87 µKat/L; P < 0.001), and serum iron (17.65 ± 6.68 vs 14.96 ± 4.72 µM; P = 0.011), and lower leukocyte and platelet counts (P = 0.010 and P < 0.001, respectively) than HCV-negative (HCV-) patients. HCV+ dialysis patients had higher diastolic blood pressure than HCV- patients (87.5 ± 6.7 vs 81.5 ± 6.0 mmHg; P = 0.005) and a lower prevalence of diabetic retinopathy (75 vs 92.7%; P = 0.007). In conclusion, our study showed that HCV is common among subjects with type 2 DM but is not associated with a higher prevalence of chronic diabetic complications.

In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics

In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones.

Association of rs12255372 in theTCF7L2 gene with type 2 diabetes mellitus: a meta-analysis

Our objective was to evaluate the association of rs12255372 in theTCF7L2 gene with type 2 diabetes mellitus (T2DM) in the world population. We carried out a survey of the literature about the effect of rs12255372 on genetic susceptibility to T2DM by consulting PubMed, the Cochrane Library, and Embase from 2006 to 2012, and then performed a meta-analysis of all the studies in order to evaluate the association between rs12255372 and T2DM. A total of 33 articles including 42 studies (with 34,076 cases and 36,192 controls) were confirmed to be eligible and were included in the final meta-analysis: 6 studies conducted on Europeans, 14 on Caucasians, 17 on Asians, 2 on Africans, and 3 on Americans. Overall, the effect size was as follows: for the variant allele T (OR = 1.387, 95%CI = 1.351-1.424), for the TT genotype (OR = 1.933, 95%CI = 1.815-2.057), for the GT genotype (OR = 1.363, 95%CI = 1.315-1.413), for the dominant model (OR = 1.425, 95%CI = 1.344-1.510), and for the recessive model (OR = 1.659, 95%CI = 1.563-1.761). In summary, by pooling all available qualified data from genetic studies on rs12255372 and T2DM, we have confirmed that rs12255372 is significantly associated with susceptibility to T2DM in the global population.

Effects of rosiglitazone on serum paraoxonase activity and metabolic parameters in patients with type 2 diabetes mellitus

Human serum paraoxonase contributes to the anti-atherogenic effect of high-density lipoprotein cholesterol (HDL-C) and has been shown to protect both low-density lipoprotein cholesterol (LDL-C) and HDL-C against lipid peroxidation. We investigated the effects of rosiglitazone on paraoxonase activity and metabolic parameters in patients with type 2 diabetes mellitus [50 patients (30 males, 20 females); mean±SD age: 58.7±9.2 years, body mass index: 28.2±4.1'kg/m2], in whom glucose control could not be achieved despite treatment with metformin, sulphonylurea, and/or insulin. The patients were given 4'mg/day rosiglitazone for 3 months in addition to their usual treatment. Serum paraoxonase activity, malondialdehyde, homocysteine, and lipid profile were measured at the time of initiation and at the end of therapy with rosiglitazone. After rosiglitazone therapy, serum levels of HDL-C, apolipoprotein A-1, and paraoxonase activity increased significantly (P<0.05) and malondialdehyde, homocysteine, lipoprotein(a), and glucose levels decreased significantly (P<0.05), but no significant changes in levels of total cholesterol and apolipoprotein B were observed. Triglyceride levels also increased significantly (P<0.05). Rosiglitazone treatment led to an improvement in glycemic control and to an increase in paraoxonase activity and HDL-C levels. Although rosiglitazone showed favorable effects on oxidant/antioxidant balance and lipid profile, further studies are needed to determine the effect of rosiglitazone on cardiovascular risk factors and cardiovascular morbidity and mortality.

Genetic analysis of the ELOVL6 gene polymorphism associated with type 2 diabetes mellitus

Recent animal studies have indicated that overexpression of the elongation of long-chain fatty acids family member 6 (Elovl6) gene can cause insulin resistance and β-cell dysfunction. These are the major factors involved in the development of type 2 diabetes mellitus (T2DM). To identify the relationship between single nucleotide polymorphisms (SNP) ofELOVL6 and T2DM pathogenesis, we conducted a case-control study of 610 Han Chinese individuals (328 newly diagnosed T2DM and 282 healthy subjects). Insulin resistance and islet first-phase secretion function were evaluated by assessment of insulin resistance in a homeostasis model (HOMA-IR) and an arginine stimulation test. Three SNPs of the ELOVL6 gene were genotyped with polymerase chain reaction-restriction fragment length polymorphism, with DNA sequencing used to confirm the results. Only genotypes TT and CT of the ELOVL6 SNP rs12504538 were detected in the samples. Genotype CC was not observed. The T2DM group had a higher frequency of the C allele and the CT genotype than the control group. Subjects with the CT genotype had higher HOMA-IR values than those with the TT genotype. In addition, no statistical significance was observed between the genotype and allele frequencies of the control and T2DM groups for SNPs rs17041272 and rs6824447. The study indicated that the ELOVL6 gene polymorphism rs12504538 is associated with an increased risk of T2DM, because it causes an increase in insulin resistance.

Peroxiredoxin isoforms are associated with cardiovascular risk factors in type 2 diabetes mellitus

The production of oxygen free radicals in type 2 diabetes mellitus contributes to the development of complications, especially the cardiovascular-related ones. Peroxiredoxins (PRDXs) are antioxidant enzymes that combat oxidative stress. The aim of this study was to investigate the associations between the levels of PRDX isoforms (1, 2, 4, and 6) and cardiovascular risk factors in type 2 diabetes mellitus. Fifty-three patients with type 2 diabetes mellitus (28F/25M) and 25 healthy control subjects (7F/18M) were enrolled. We measured the plasma levels of each PRDX isoform and analyzed their correlations with cardiovascular risk factors. The plasma PRDX1, -2, -4, and -6 levels were higher in the diabetic patients than in the healthy control subjects. PRDX2 and -6 levels were negatively correlated with diastolic blood pressure, fasting blood sugar, and hemoglobin A1c. In contrast, PRDX1 levels were positively correlated with low-density lipoprotein and C-reactive protein levels. PRDX4 levels were negatively correlated with triglycerides. In conclusion, PRDX1, -2, -4, and -6 showed differential correlations with a variety of traditional cardiovascular risk factors. These results should encourage further research into the crosstalk between PRDX isoforms and cardiovascular risk factors.

Cytokine profile and lymphocyte subsets in type 2 diabetes

Type 2 diabetes mellitus (T2D) is a metabolic disease with inflammation as an important pathogenic background. However, the pattern of immune cell subsets and the cytokine profile associated with development of T2D are unclear. The objective of this study was to evaluate different components of the immune system in T2D patients' peripheral blood by quantifying the frequency of lymphocyte subsets and intracellular pro- and anti-inflammatory cytokine production by T cells. Clinical data and blood samples were collected from 22 men (51.6±6.3 years old) with T2D and 20 nonsmoking men (49.4±7.6 years old) who were matched for age and sex as control subjects. Glycated hemoglobin, high-sensitivity C-reactive protein concentrations, and the lipid profile were measured by a commercially available automated system. Frequencies of lymphocyte subsets in peripheral blood and intracellular production of interleukin (IL)-4, IL-10, IL-17, tumor necrosis factor-α, and interferon-γ cytokines by CD3+ T cells were assessed by flow cytometry. No differences were observed in the frequency of CD19+ B cells, CD3+CD8+ and CD3+CD4+ T cells, CD16+56+ NK cells, and CD4+CD25+Foxp3+ T regulatory cells in patients with T2D compared with controls. The numbers of IL-10- and IL-17-producing CD3+ T cells were significantly higher in patients with T2D than in controls (P<0.05). The frequency of interferon-γ-producing CD3+ T cells was positively correlated with body mass index (r=0.59; P=0.01). In conclusion, this study shows increased numbers of circulating IL-10- and IL-17-producing CD3+ T cells in patients with T2D, suggesting that these cytokines are involved in the immune pathology of this disease.

The effect of a diet education with six iso-caloric meals on the body weight and blood glucose of diabetes type 2 patients

The treatment of Diabetes should not only be sought through drug administration; diet is also a part of its treatment. The aim of this study was to determine the effect of a diet with six meals having equal calories on the body weight and blood glucose on diabetes type 2 patients. This research is an Experimental study conducted in 2009 on 181 patients with diabetes. The patients visited the IDSF (Iranian Diabetes Society of Fars) weekly and the patients to be studied were randomly divided into two groups of 85 and 96 patients, respectively. The participants were repeatedly requested to consume their calculated calorie in six equal parts. The average age in the Experimental and Control groups were 51.2 ± 13.3 and 53.1 ± 9.4, respectively. The mean body weight and fasting blood glucose at the beginning of the study in Experimental and Control groups were 66.3 ± 9.4 and 69.1 ± 11.1 kg, 198.9 ± 35.1, and 199.8 ± 39.1 mg.dL-1, respectively. At the end of the study, however, the values were 63.5 ± 7.5 and 66.98 ± 9 kg, 139.5 ± 34.6 and 164.2 ± 22.1 mg.dL-1, respectively. Only the mean fasting blood glucose at the end of the study revealed a significant difference (p-value = 0.001). The results show that educating those afflicted with Diabetes Type 2 aiming at changing their diet can greatly help them manage their blood glucose.

Development of a bovine adenovirus type 2-based gene delivery vector /

ABSTRACT Recombinant adenoviruses are currently under intense investigation as potential gene delivery and gene expression vectors with applications in human and veterinary medicine. As part of our efforts to develop a bovine adenovirus type 2 (BAV2) based vector system, the nucleotide sequence of BAV2 was determined. Sixty-six open reading frames (ORFs) were found with the potential to encode polypeptides that were at least 50 amino acid (aa) residue long. Thirty-one of the BAV2 polypeptide sequences were found to share homology to already identified adenovirus proteins. The arrangement of the genes revealed that the BAV2 genomic organization closely resembles that of well-characterized human adenoviruses. In the course of this study, continuous propagation of BAV2 over many generations in cell culture resulted in the isolation of a BAV2 spontaneous mutant in which the E3 region was deleted. Restriction enzyme, sequencing and PCR analyses produced concordant results that precisely located the deletion and revealed that its size was exactly 1299 bp. The E3-deleted virus was plaque-purified and further propagated in cell culture. It appeared that the replication of such a virus lacking a portion of the E3 region was not affected, at least in cell culture. Attempts to rescue a recombinant BAV2 virus with the bacterial kanamycin resistance gene in the E3 region yielded a candidate as verified with extensive Southern blotting and PCR analyses. Attempts to purify the recombinant virus were not successful, suggesting that such recombinant BAV2 was helper-dependent. Ten clones containing full-length BAV2 genomes in a pWE15 cosmid vector were constructed. The infectivity of these constructs was tested by using different transfection methods. The BAV2 genomic clones did appear to be infectious only after extended incubation period. This may be due to limitations of various transfection methods tested, or biological differences between virus- and E. co//-derived BAV2 DNA.

Locating and sequencing of the E3 and neighbouring regions in bovine advenovirus type 2

Adenoviruses are nonenveloped icosahedral shaped particles. The double stranded DNA viral genome is divided into 5 major early transcription units, designated E1 A, E1 B, and E2 to E4, which are expressed in a regulated manner soon after infection. The gene products of the early region 3 (E3), shown to be nonessential for viral replication in vitro, are believed to be involved in counteracting host immunosurveillance. In order to sequence the E3 region of Bovine adenovirus type 2 (BAV2) it was necessary to determine the restriction map for the plasmid pEA48. A physical restriction endonuclease map for BamHl, Clal, Eco RI, Hindlll, Kpnl, Pstt, Sail, and Xbal was constructed. The DNA insert in pEA48 was determined to be viral in origin using Southern hybridization. A human adenovirus type 5 recombinant plasmid, containing partial DNA fragments of the two transcription units L4 and L5 that lie just outside the E3, was used to localize this region. The recombinant plasmid pEA was subcloned to facilitate sequencing. The DNA sequences between 74.8 and 90.5 map units containing the E3, the hexon associated protein (pVIII), and the fibre gene were determined. Homology comparison revealed that the genes for the hexon associated pV11I and the fibre protein are conserved. The last 70 amino acids of the BAV2 pV11I were the most conserved, showing a similarity of 87 percent with Ad2 pV1I1. A comparison between the predicted amino acid sequences of BAV2 and Ad40, Ad41 , Ad2 and AdS, revealed that they have an identical secondary structure consisting of a tail, a shaft and a knob. The shaft is composed of 22, 15 amino acid motifs, with periodic glycines and hydrophobic residues. The E3 region was found to consist of about 2.3 Kbp and to encode four proteins that were greater than 60 amino acids. However, these four open reading frames did not show significant homology to any other known adenovirus DNA or protein sequence.

Molecular cloning restriction enzyme analysis, bovine adenovirus type 2 genome

Adenoviruses are non-enveloped icosahedral-shaped particles which possess a double-stranded DNA genome. Currently, nearly 100 serotypes of adenoviruses have been identified, 48 of which are of human origin. Bovine adenoviruses (BAVs), causing both mild respiratory and/or enteral diseases in cattle, have been reported in many countries all over the world. Currently, nine serotypes of SAVs have been isolated which have been placed into two subgroups based on a number of characteristics which include complement fixation tests as well as the ability to replicate in various cell lines. Bovine adenovirus type 2 (BAV2), belonging to subgroup I, is able to cause pneumonia as well as pneumonic-like symptoms in calves. In this study, the genome of BAV2 (strain No. 19) was subcloned into the plasmid vector pUC19. In total, 16 plasmids were constructed; three carry internal San fragments (spanning 3.1 to 65.2% ), and 10 carry internal Pstl fragments (spanning 4.9 to 97.4%), of the viral genome. Each of these plasmids was analyzed using twelve restriction endonucleases; BamHI, CiaI, EcoRl, HiOOlll, Kpnl, Noll, NS(N, Ps~, Pvul, Saj, Xbal, and Xhol. Terminal end fragments were also cloned and analyzed, sUbsequent to the removal of the 5' terminal protein, in the form of 2 BamHI B fragments, cloned in opposite orientations (spanning 0 to 18.1°k), and one Pstll fragment (spanning 97.4 to 1000/0). These cloned fragments, along with two other plasmids previously constructed carrying internal EcoRI fragments (spanning 20.6 to 90.5%), were then used to construct a detailed physical restriction map using the twelve restriction endonucleases, as well as to estimate the size of the genome for BAV2(32.5 Kbp). The DNA sequences of the early region 1 (E1) and hexon-associated gene (protein IX) have also been determined. The amino acid sequences of four open reading frames (ORFs) have been compared to those of the E1 proteins and protein IX from other Ads.

Permissivity of human HeLa cells to bovine adenovirus type 2 (BaV2 infection

Infection of hUlnan cells by bovine adenovirlls type 2 (BAV2) is abortive. To obtain a better understanding of this pllenomel1011, and in particular to identify Wllich steps in the viral replicative cycles are altered dllring this virlls-host cells interaction, we have llndertaken a detailed study of BAV2 infections of the nonpennissive hUlnan IIeLa cells. Using autoradiography and 3H-thymidine-labeled vvhole virus particles for infection of HeLa cells, vve determined that viral attachluent appears normal. Furthermore, Southern analysis revealed that internalization and transport to the nuclells occurs in BAV2 infected HeLa cells. To investigate viral DNi\ synthesis, infectivity assays involving hydroxyllrea, a viral DN-A synthesis inhibitor, were carried out. The results revealed that Bft:LV2 DNA synthesis does not occur in HeLa cells. Fllrtller investigations into viral early gene expression by northern blotting analyses indicated that HeLa cells fail to support expression of EIA. This suggested that abortive infection by BAV2 could be attributed to faiiure of EIA to express. To test the possibility that the failure to express ElA was due to the inability of the host cell to recognize the E lA prOlTIoter, ,ve carried out transient expression transfection experiments using plaslnids \vith the bacterial lacZ linder the control of either BAV2 or i\d5 EIA promoter. X-gal histochelIlical assays sho\ved expression of lacZ from the Ad5 ElA prOlnoter but no expression of lacZ [rOln the BAV2 EIA prOlTIoter. This further suggests that the abortive infection b:y BAV2 could be attributed to failure of EIA to express dlle to a nonfllnctional prOlTIoter in hlunan cells. Thus we speClllated that abortive infection of HeLa cells by adenoviruses may be averted by providing EtA functions in trans. To demonstrate this, we coinfected HeLa cells with Ad5 and BAV2, reasoning that Ad5 could cOlnpensate for EIA deficiency in BAV2. OUf results showed that BAV2 DNA synthesis was indeed Sllpported in HeLa cells coinfected with Ad5dlE3 as revealed by Southern analysis. In contrast, coinfection of HeLa cells \vith BAV2 and Ad5dlElE3 mutallt did not support BLt\V2 DNA synthesis. Interestingly, BAV2 failed to replicate in 293 cells which are constitlltively expressing the El genes. This could ilnply that El is necessary but not sufficient to avert the failllre ofBAV2 to undergo productive infection ofhulnan cells.

The cloning and reconstitution of a bovine adenovirus type 2 E3 deletion mutant and the sequencing and analysis of the early 4 region

Recombinant Adenoviruses (Ads) have been shown to have potential applications in three areas: gene therapy, high level protein expression and recombinant vaccines.' At least three different locations within the Ad genome can be deleted and subsequently used for the insertion of foreign sequences. These include the Early 3 (E3), Early 1 (E1) and Early 4 (E4) regions. Viral vectors of this type have been well studied in Human Ads 2 and 5, however one has not yet been constructed for Bovine Adenovirus Type 2 (BAV2). The E3 region is located between 76.6 and 86 m.u. on the r-strand and is transcribed in a rightward direction. The gene products of the Early 3 region (E3) have been shown to be non-essential for viral replication, in vitro, but are required for host immunosurveillance. This study represents the cloning and reconstitution of a BAV2 E3 deletion mutant. A deletion of 1800bp was made within the E3 region of BAV2 and the thymidine kinase gene was subsequently inserted in the deleted area . . The plasmid pdlE3-4tk1 (23.4Kbp) was constructed and used to to facilitate homologous recombination with the wild type BAV2 to produce a mutant. Southern Blotting and Hybridization results suggest the presence of a BAV2 E3 deletion mutant with thymidine kinase sequences present. The E4 region of Human Adenovirus types 2 and 5 is located at the extreme right end of the genome (91.3 map units - 99.1 map units) and is transcribed in a leftward direction giving rise to a complicated set of differentially spliced mRNAs. Essentially there are 7 open reading frames (ORFs) encoding for at least 7 polypeptides. The gene products encoded by the E4 region have been shown to be essential for the expression of late viral genes, host cell shutoff and normal viral growth. We have cloned and sequenced the right end segment between 90.5 map units and 100 map units of the BAV2 genome. The results show several open reading frames which encode polypeptides exhibiting homology to three polypeptides encoded by the E4 region of human adenovirus type 2. These include the 14kDa protein encoded by ORF1, the 34kDa protein encoded by ORF6 and the 13kDa protein encoded by ORF3. The nucleotide sequence, restriction enzyme map, and ORF map of the E4 region could be very useful in future molecular manipulation of this region and could possibly explain the slow growth rate of BAV2 in MDBK cells.

Régulation de la lipoprotéine lipase macrophagique et de LOX-1 par des facteurs métaboliques. Implications dans l’athérosclérose associée au diabète de type 2.

Les maladies cardiovasculaires (MCV) sont la principale cause de décès dans les pays occidentaux et constituent la principale complication associée au diabète. La lipoprotéine lipase (LPL) est une enzyme clé du métabolisme des lipides et est responsable de l'hydrolyse des lipoprotéines riches en triglycérides (TG). Plusieurs études ont démontré que la LPL sécrétée par les macrophages dans la paroi artérielle est pro-athérogénique. La dysfonction endothéliale caractérise les stades précoces du processus athérosclérotique. Il a été observé qu’un récepteur nouvellement identifié des lipoprotéines de basse densité oxydées (LDLox), le récepteur de type lectine des LDLox (LOX-1), est fortement exprimé dans les lésions athérosclérotiques humaines et dans l’aorte de rats diabétiques, suggérant un rôle clé de LOX-1 dans la pathogénèse de l’athérosclérose diabétique. Au vu du rôle potentiel de la LPL macrophagique et du LOX-1 dans l’athérosclérose associée au diabète de type 2, nous avons évalué la régulation de ces deux molécules pro-athérogéniques par des facteurs métaboliques et inflammatoires augmentés dans le diabète, soit la leptine, l’acide linoléique (LA) et la protéine C-réactive (CRP). Nos résultats démontrent que : 1) Dans les cellules endothéliales aortiques humaines (HAECs), LA augmente l’expression protéique de LOX-1 de façon temps- et dose-dépendante; 2) La pré-incubation de HAECs avec des antioxydants et des inhibiteurs de la NADPH oxydase, de la protéine kinase C (PKC) et du facteur nucléaire-kappa B (NF-kB), inhibe l’effet stimulant de LA sur l’expression protéique de LOX-1; 3) Dans les HAECs traitées avec LA, on observe une augmentation d’expression des isoformes classiques de la PKC; 4) LA augmente de manière significative l’expression génique de LOX-1 ainsi que la liaison des protéines nucléaires extraites des HAECs à la séquence régulatrice NF-kB présente dans le promoteur du gène de LOX-1; 5) LA augmente, via LOX-1, la captation des LDLox par les cellules endothéliales. Pris dans leur ensemble, ces résultats démontrent que LA augmente l’expression endothéliale de LOX-1 in vitro et appuient le rôle clé de LA dans la dysfonction endothéliale associée au diabète. Au vu de nos études antérieures démontrant qu’une expression accrue de LPL macrophagique chez les patients diabétiques de type 2 et que l’augmentation de facteurs métaboliques dans cette maladie, soit l’homocystéine (Hcys), les acides gras et les produits terminaux de glycation (AGE), accroissent l’expression de la LPL macrophagique, nous avons par la suite déterminé l’effet, in vitro, de deux autres facteurs métaboliques et inflammatoires surexprimés dans le diabète, soit la leptine et la CRP, sur l’expression de la LPL macrophagique. Les concentrations plasmatiques de leptine sont élevées chez les patients diabétiques et sont associées à un accroissement des risques cardiovasculaires. Nous avons démontré que : 1) Dans les macrophages humains, la leptine augmente l’expression de la LPL, tant au niveau génique que protéique; 2) L’effet stimulant de la leptine sur la LPL est aboli par la pré-incubation avec un anticorps dirigé contre les récepteurs à la leptine (Ob-R), des inhibiteurs de la PKC et des antioxydants; 3) La leptine augmente l’expression membranaire des isoformes classiques de la PKC et la diminution de l’expression endogène de la PKC, abolit l’effet de la leptine sur l’expression de la LPL macrophagique; 4) Dans les macrophages murins, la leptine augmente le taux de synthèse de la LPL et augmente la liaison de protéines nucléaires à la séquence protéine activée-1 (AP-1) du promoteur du gène de la LPL. Ces observations supportent la possibilité que la leptine puisse représenter un facteur stimulant de la LPL macrophagique dans le diabète. Finalement, nous avons déterminé, in vitro, l’effet de la CRP sur l’expression de la LPL macrophagique. La CRP est une molécule inflammatoire et un puissant prédicteur d’événements cardiovasculaires. Des concentrations élevées de CRP sérique sont documentées chez les patients diabétiques de type 2. Nous avons démontré que : 1) Dans les macrophages humains, la CRP augmente l’expression de la LPL au niveau génique et protéique et la liaison de la CRP aux récepteurs CD32 est nécessaire pour médier ses effets; 2) La pré-incubation de macrophages humains avec des antioxydants, des inhibiteurs de la PKC et de la protéine kinase mitogénique activée (MAPK), prévient l’induction de la LPL par la CRP; 3) La CRP augmente l’activité de la LPL, la génération intracellulaire d’espèces radicalaires oxygénées (ROS), l’expression d’isoformes classiques de la PKC et la phosphorylation des kinases extracellulaires régulées 1/2 (ERK 1/2); 4) Les macrophages murins traités avec la CRP démontrent une augmentation de la liaison des protéines nucléaires à la séquence AP-1 du promoteur du gène de la LPL. Ces données suggèrent que la LPL puisse représenter un nouveau facteur médiant les effets délétères de la CRP dans la vasculopathie diabétique. Dans l’ensemble nos études démontrent le rôle clé de facteurs métaboliques et inflammatoires dans la régulation vasculaire de la LPL et du LOX-1 dans le diabète. Nos données suggèrent que la LPL et le LOX-1 puissent représenter des contributeurs clé de l’athérogénèse accélérée associée au diabète chez l’humain. Mots-clés : athérosclérose, maladies cardiovasculaires, diabète de type 2, macrophage, LPL, cellules endothéliales, LOX-1, stress oxydatif, leptine, LA, CRP.