3-nitrotyrosine and Dilatation--Pathologic

In abdominal aortic aneurysm (AAA), pathophysiology deterioration of the medial aortic layer plays a critical role. Key players in vessel wall degeneration are reactive oxygen species (ROS), smooth muscle cell apoptosis, and extracellular matrix degeneration by matrix metalloproteinase-9 (MMP-9). Lipocalin-2, also neutrophil gelatinase-associated lipocalin (NGAL), is suggested to be involved in these degenerative processes in other cardiovascular diseases. We aimed to further investigate the role of NGAL in AAA development and rupture.. In this observational study, aneurysm tissue and blood of ruptured (n = 13) AAA patients were investigated versus nonruptured (n = 26) patients. Nondilated aortas (n = 5) from deceased patients and venous blood from healthy volunteers (n = 10) served as controls. NGAL concentrations in tissue and blood were measured by enzyme-linked immunosorbent assay and immunofluorescence microscopy. Nitrotyrosine (marker of ROS), MMP-9, and caspase-3 (marker of apoptosis) in aneurysm tissue were measured by immunofluorescence microscopy. AAA expansion rates were calculated retrospectively.. NGAL (in μg/mL) blood concentration in ruptured AAA was 46 (range 22-122) vs. 26 (range 6-55) in nonruptured AAA (P < 0.01) and 14 (range 12-22) in controls (P < 0.01). In the aneurysm wall of ruptured AAA, NGAL concentration was 4.7 (range 1.4-25) vs. 4.4 (range 0.2-14) in nonruptured AAA (not significant) and 1.8 (range 1.2-2.7) in nondilated aortas (P = 0.04). In the medial layer, NGAL correlated positively with nitrotyrosine (Rs = 0.80, P < 0.01), MMP-9 (Rs = 0.56, P = 0.02), and caspase-3 (Rs = 0.75, P = 0.01). NGAL did not correlate to AAA expansion rate in blood or tissue (P = 0.34 and P = 0.95, respectively).. This study demonstrates that NGAL blood concentration is higher in ruptured AAA patients than in nonruptured AAA. NGAL expression in the AAA wall is also higher than in nondilated aorta. Furthermore, its expression is associated with factors of vessel wall deterioration. Based on our study results, we could not determine NGAL as a biomarker for AAA growth or rupture. However, our findings do support a potential role of NGAL in the development of AAA.

Topics: Adult; Aged; Aged, 80 and over; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Aortic Rupture; Apoptosis; Biomarkers; Caspase 3; Dilatation, Pathologic; Disease Progression; Female; Humans; Lipocalin-2; Male; Matrix Metalloproteinase 9; Middle Aged; Oxidative Stress; Retrospective Studies; Tyrosine; Up-Regulation; Vascular Remodeling

Our aim was to determine whether the repeated, binge administration of 3,4-methylenedioxymethamphetamine (ecstasy; MDMA) produces structural and/or functional changes in the myocardium that are associated with oxidative stress.. Echocardiography and pressure-volume conductance catheters were used to assess left ventricular (LV) structure and function in rats subjected to four ecstasy binges (9 mg/kg i.v. for 4 days, separated by a 10 day drug-free period). Hearts from treated and control rats were used for either biochemical and proteomic analysis or the isolation of adult LV myocytes. After the fourth binge, treated hearts showed eccentric LV dilation and diastolic dysfunction. Systolic function was not altered in vivo; however, the magnitude of the contractile responses to electrical stimulation was significantly smaller in myocytes from rats treated in vivo with ecstasy compared with myocytes from control rats. The magnitude of the peak increase in intracellular calcium (measured by Fura-2) was also significantly smaller in myocytes from ecstasy-treated vs. control rats. The relaxation kinetics of the intracellular calcium transients were significantly longer in myocytes from ecstasy-treated rats. Ecstasy significantly increased nitrotyrosine content in the left ventricle. Proteomic analysis revealed increased nitration of contractile proteins (troponin-T, tropomyosin alpha-1 chain, myosin light polypeptide, and myosin regulatory light chain), mitochondrial proteins (Ub-cytochrome-c reductase and ATP synthase), and sarcoplasmic reticulum calcium ATPase.. The repeated binge administration of ecstasy produces eccentric LV dilation and dysfunction that is accompanied by oxidative stress. These functional responses may result from the redox modification of proteins involved in excitation-contraction coupling and/or mitochondrial energy production. Together, these results indicate that ecstasy has the potential to produce serious cardiac toxicity and ventricular dysfunction.

Topics: Animals; Calcium Signaling; Cells, Cultured; Diastole; Dilatation, Pathologic; Electric Stimulation; Hallucinogens; Heart Ventricles; Injections, Intravenous; Kinetics; Male; Muscle Proteins; Myocardial Contraction; Myocytes, Cardiac; N-Methyl-3,4-methylenedioxyamphetamine; Oxidative Stress; Rats; Rats, Sprague-Dawley; Systole; Tyrosine; Ultrasonography; Ventricular Dysfunction, Left

The redox pathophysiology of vascular repair is incompletely understood. We assessed the role of vascular superoxide dismutase (SOD) activity in oxidative/nitrative stress and caliber loss postinjury (PI).. Rabbits submitted to iliac artery balloon overdistension were followed for 14 days PI. Significant decrease in vascular SOD activity occurred at 7 and 14 days PI (by 45% and 34%, respectively, versus control, 96+/-1 U/mg, P<0.05). Separation in concanavalin-A column showed that both extracellular SOD (ecSOD) and CuZn SOD activities were reduced, whereas Western analysis showed normal or augmented protein expression. Immunoreactivity to nitrotyrosine, neuronal NO synthase (NOS), and inducible NOS (iNOS) increased in media and neointima PI; iNOS mRNA also augmented. Administration of ecSOD from days 7 to 14 PI corrected the SOD activity decrease and minimized caliber loss by 59% (P=0.007) despite unaltered neointima. Nitrate levels markedly increased with ecSOD in injured artery homogenates (26+/-5 versus 4+/-0.3 micromol/L per mg, P=0.001). Such increase was 70% inhibited by specific iNOS antagonist 1400w. Nitrotyrosine and neuronal NOS expression decreased after ecSOD.. Sustained low vascular SOD activity has a key role in constrictive remodeling after injury, promoting oxidative/nitrative stress and impairment of iNOS-derived NO bioavailability. SOD function may critically determine whether iNOS induction is beneficial or deleterious in vivo.

Topics: Animals; Catheterization; Constriction, Pathologic; Dilatation, Pathologic; Down-Regulation; Iliac Artery; Neovascularization, Pathologic; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Oxidative Stress; Rabbits; Superoxide Dismutase; Tunica Intima; Tunica Media; Tyrosine

To determine if nitric oxide synthase (NOS) contributes to the pathophysiology of abdominal aortic aneurysms (AAAs), C57BL/6J mice underwent transient aortic injury to induce a chronic inflammatory response. Wild-type mice developed a significant increase in aortic diameter within 14 days of elastase perfusion (115+/-16%, 40% incidence of AAAs), along with intense and widespread staining for nitrotyrosine, mononuclear inflammation, and delayed destruction of the elastic lamellae. Expression of both endothelial and neuronal forms of NOS was substantially decreased within AAAs, whereas inducible NOS (iNOS) mRNA was increased 360%, and the enzyme was localized to infiltrating inflammatory cells. By using mice with targeted deletion of iNOS to evaluate the functional importance of this enzyme, male iNOS(-/-) mice developed the same extent of aneurysmal dilatation as congenic controls (121+/-22%, 40% incidence of AAAs) and exhibited similar structural features except for diminished nitrotyrosine staining. Aneurysmal dilatation was actually enhanced in female iNOS(-/-) mice (141+/-16%, 80% incidence of AAAs; P<0.05), but this effect was reversed by previous oophorectomy. Although extensive protein nitration and increased expression of iNOS accompany the development of elastase-induced experimental AAAs, iNOS is not required in this process and its absence may be deleterious.

Topics: Animals; Aortic Aneurysm, Abdominal; Dilatation, Pathologic; Female; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Ovariectomy; Pancreatic Elastase; RNA, Messenger; Tyrosine