Naoichiro Hattan

Louisiana State University Health Sciences Center New Orleans, Baton Rouge, LA, United States

Are you Naoichiro Hattan?

Claim your profile

Publications (11)36.08 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The metabolic syndrome (MS), a condition characterized by several risk factors for coronary artery disease, including obesity, is associated with endothelial dysfunction and oxidative stress. Because proper endothelial function is essential for signaling of certain growth factors (vascular endothelial growth factor, VEGF) we hypothesized that coronary collateral growth (CCG) is impaired in a model of the MS. To test this hypothesis, we stimulated coronary collateral growth in pre-diabetic Zucker obese fatty rats (OZR) and lean littermates (LZR) by using episodic, repetitive ischemia (RI: 40 s left anterior descending arterial occlusion, 24/d for 14 d). Myocardial blood flow (MBF, radioactive microspheres) was measured in the normal (NZ) and collateral-dependent (ischemic) zones (CZ); CCG was assessed as a ratio of CZ/NZ flow (unity represents complete restoration of CZ flow). In LZR, CZ/NZ ratio increased from 0.18 +/- 0.03 to 0.81 +/- 0.07 after RI (P < 0.05). In contrast, in OZR rats CZ/NZ did not increase after RI (0.15 +/- 0.04 vs 0.18 +/- 0.04). To rectify abrogated collateral growth in OZR, we employed VEGF gene therapy (VEGF-transduced, strained-matched, cultured vascular smooth muscle cells [cVSMCs], delivered intracoronary). VEGF therapy modestly but not significantly increased the CZ/NZ ratio after RI (0.16 +/- 0.05 vs 0.33 +/- 0.06). To facilitate VEGF signaling,we reduced oxidative stress by transducing cVSMCs with both ecSOD and VEGF. This increased the CZ/NZ flow ratio after RI to 0.52 +/- 0.04 (p < 0.05 vs. OZR [(0.19 +/- 0.04]) indicating partial restoration of collateral growth. Our results demonstrate that coronary collateral growth is impaired in a model of the metabolic syndrome and that growth factor gene therapy with VEGF is made far more effective when it is coupled to an intervention that reduces oxidative stress.
    Archiv für Kreislaufforschung 05/2007; 102(3):217-23. · 5.90 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: For therapeutic angiogenesis to achieve clinical relevance, it must be effective, with minimal side effects to other end organ systems. We developed a cardiac-specific gene delivery mechanism by transfecting autologous vascular smooth muscle cells (VSMC) with VEGF and administering these cells via intracoronary injection. We evaluated the efficacy of this protocol by its ability to stimulate angiogenesis in the presence of a subthreshold stimulus for collateralization. A modified canine repetitive coronary occlusion model was utilized in these experiments with left anterior descending coronary artery occlusions for 2 min every 2 h four times per day for 21 days. An intramyocardial catheter in the perfusion territory of the left anterior descending coronary artery measured proteins in the myocardial interstitial fluid. VSMC from jugular vein explants were isolated, amplified in culture for 3 wk, and transfected with a plasmid expressing VEGF-165 and/or enhanced green fluorescent protein. Cells were injected before commencement of occlusions. VEGF levels in myocardial interstitial fluid were significantly higher in VEGF-transfected animals than in sham (repetitive occlusions without cell transplantation) and control (repetitive occlusions with enhanced green fluorescent protein-transfected cells) animals at the onset of occlusions (P < 0.05). In the VEGF group, collateral flow was increased at day 7 and remained higher than in sham and control groups thereafter. We found that intracoronary administration of VEGF-transfected autologous VSMC effectively promotes collateral development. This approach may provide a way to confine delivery of a gene to a specified organ, thus minimizing complications related to gene transfection in nontargeted organ systems.
    AJP Heart and Circulatory Physiology 08/2004; 287(2):H488-93. · 3.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ischemic injury to the kidney results in blood vessel loss and predisposition to chronic renal disease. Angiostatin is a proteolytic cleavage product of plasminogen that inhibits angiogenesis, promotes apoptosis of endothelial cells, and disrupts capillary integrity. A combination of lysine-Sepharose enrichment followed by Western blotting was used to study the expression of angiostatin in response to the induction of ischemic renal injury. No angiostatin products were readily detectable in kidneys of sham-operated control rats. In contrast, both 38- and 50-kDa forms of angiostatin were dramatically enhanced in the first 3 days following 45-min ischemia-reperfusion injury. Renal angiostatin levels declined but remained detectable at late time points postrecovery (8-35 days postischemia). Angiostatin-like immunoreactivity was also elevated in the plasma and in urine for up to 35 days following injury. Lysine-Sepharose extracts of either kidney or urine inhibited vascular endothelial cell growth factor-induced proliferation of human aortic endothelial cells in vitro; an effect that was blocked by coincubation with an angiostatin antibody. RT-PCR verified that mRNA of the parent protein plasminogen was produced in the liver, but it was not present in either sham-operated or postischemic kidney. Matrix metalloproteinase (MMP)-2 and MMP-9, which may mediate angiostatin generation, were enhanced in postischemic kidney tissue and were localized to the renal tubules, interstitial cells, and the tubulo-interstitial space. These data indicate the possible local synthesis of angiostatin following acute renal failure (ARF) and suggest a possible role for MMPs in this activity. Renal angiostatin generation following ARF may modulate renal capillary density postischemia and thereby influence chronic renal function.
    American journal of physiology. Renal physiology 06/2004; 286(5):F893-902. · 3.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiovascular disease (CVD) is the number one cause of mortality in the United States. However, little progress has been made in the development of effective gene therapy treatments for cardiovascular pathologies. Recently, lentiviral vectors based on HIV-1 have been developed and optimized, and have ideal characteristics for gene therapy applications to treat CVD, particularly in myocardium and vascular smooth muscle. To achieve our goal of efficient gene transfer in vivo, in vitro systems needed to be developed to assay modified lentiviral vector transduction into isolated primary rat cardiomyocytes and vascular smooth muscle cells (VSMCs). In our initial studies, lentiviral vector transduction efficiency was examined using vectors pseudotyped with the vesicular stomatitis virus G protein (VSV-G) and containing the bacterial lacZ gene driven by a number of different viral and cellular promoters, including phosphoglycerokinase (PGK), cytomegalovirus (CMV), ubiquitin (Ub) and elongation factor 1a (EF1a), CMV-EF1a hybrid (CEF) and cardiac-specific promoter α-myosin heavy chain (αMHC). All of the promoters were found to function in the cardiovascular cells, even at MOI's below 1. The promoter with the highest transduction efficiency was CEF (3.37 × 105 T.U./ng p24; n=5 preparations in triplicate) as determined by end-point dilution and p24 Gag ELISA, whereas the PGK promoter resulted in the lowest lentiviral vector titer (7.14 × 102 T.U./ng p24; n=5 preparations in triplicate). The CEF promoter was then used to determine lentiviral vector transduction efficiency in isolated rat primary VSMCs from the jugular vein and thoracic aorta. The VSMCs were difficult to infect, with multiple infections (MOI=10/infection) being necessary to achieve high infectivity (i.e., greater than 85% of the VSMCs). Interestingly, the cells from the aorta were slightly more transducible than those from the jugular vein. The relatively low infectivity in the VSMCs may be one reason that VSV-G pseudotyped lentivectors have been unable to effectively transduce these cells in vivo. We have analyzed each of the promoters to assess their ability to drive gene expression in primary rat cardiomyocytes. Following the infection of the cardiomyocytes at a MOI of 1, we determined the β-gal transgene expression for each of the promoters, and found that the PGK promoter produced the highest level of β-gal protein (1497 ± 129 pg β-gal/mg total protein; n=5 preparations in triplicate) and no β-gal expression was observed in the mock treated cells. No significant differences were observed in lentiviral vector transduction and/or gene expression using lentiviral vectors that either contained or were devoid of the accessory proteins, specifically vif, vpr, vpu and nef. Current studies are being performed with these lentivectors to determine if the in vitro experiments in the primary cardiomyocytes correlate with in vivo transduction using different routes of administration into the heart. These studies should help to better illuminate lentiviral vectors as a gene therapy tool for use in cardiovascular disease in basic and clinical research. Funded by NHLBI 18766–01.
    Molecular Therapy 01/2004; 9. · 7.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The control of coronary blood flow has been studied for decades, but despite our extensive efforts, the critical regulators of flow are largely unknown. One purpose of this review is to summarize some recent concepts about the control of coronary flow and also point out areas where additional knowledge must be acquired. A second purpose of this review is to highlight the need for additional noninvasive measurements of flow that undoubtedly will require further evolution of contemporary technologies, and also application of specific methods toward noninvasive measurements of coronary blood flow. Only after the development of such measurements will the scientific community begin to understand the intricacies of the regulation of coronary flow in human beings.
    Journal of Nuclear Cardiology 08/2001; 8(5):599-605. · 2.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hemoperfusion with a column of polymyxin B immobilized on fibers (PMX) has been used to adsorb endotoxin in-patients with septic shock. PMX hemoperfusion (PMX-H) increases blood pressure (BP) too rapidly for the effect to be attributable to endotoxin removal. Since inducible NO synthase (iNOS) is known to be involved in the profound hypotension, we hypothesized that a decrease of tetrahydrobiopterin (BH(4)), an essential cofactor of iNOS, might account for the rapid effect of PMX-H on BP, if plasma BH(4) is increased concomitantly with NO in septic shock patients and if PMX can decrease BH(4). BH(4) was evaluated by measuring total biopterin, which can include derivatives of BH(4) by using high-performance liquid chromatography (HPLC). We confirmed that PMX fabric time dependently decreased total biopterin concentration in vitro. The plasma level of total biopterin in shock patients was indeed markedly elevated compared with that in volunteers (131.1+/-33.4 vs. 10.4+/-1.1 nM, n=5, P<0.01). Level of NO metabolites (NOx) were 173.9+/-104.7 versus 28.7+/-11.6 µM (P<0.01). In beagles, plasma total biopterin was 44.7+/-6.9 nM at baseline, reached 118+/-28.6 nM after lipopolysaccharide (LPS) injection, and fell to 70.2+/-15.8 nM after PMX-H. Plasma NOx concentration was increased from 15.2+/-4.2 to 41.0+/-7.5 µM by LPS treatment. BP was 130+/-11.3 mmHg at baseline, 82.2+/-8.3 mmHg at 14 h after LPS, and 115.2+/-16.0 mmHg after PMX-H. In rats, plasma total biopterin was 88.8+/-1.5 nM at baseline, 383.7+/-144.2 nM after LPS and 177.0+/-14.2 nM after PMX-H. Plasma NOx was also increased after LPS (from 34.6+/-4.4 to 1445.6+/-376.0 nM). The marked increase in total biopterin concomitantly with NOx in septic shock patients and its reduction by PMX-H in animal models of septic shock are consistent with our hypothesis, and appear to justify further research on BH(4) removal as a potential therapeutic target.
    Pathophysiology 04/2001; 7(4):275-281.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Restoration of coronary blood flow by angiogenesis may offer a new approach to intractable ischemic heart disease. In the present study, we investigated the angiogenic effects of gene transfer of vascular endothelial growth factor 165 on microvascular myocardial ischemia. A rabbit model of microvascular myocardial ischemia was created by plugging coronary microvessels with microspheres (15 microm in diameter, 2.8 x 10(5)/kg, n = 29). Gene transfer was performed by semi-selective intracoronary injection of recombinant adenovirus expressing vascular endothelial growth factor 165 forty minutes after microsphere injection (n = 9). Microsphere injection reduced myocardial perfusion (78% +/- 9% of baseline tissue flow) and diminished myocardial contraction (61% +/- 12% of the baseline ejection fraction) and cardiac performance (elevated left ventricular end-diastolic pressure and decreased systemic flow) in the acute phase. At 17 +/- 3 days, gene transfer of vascular endothelial growth factor 165 had had the following effects: (1) promoted coronary angiogenesis as evidenced by myocardial flow above the baseline (121% +/- 24%), (2) increased vascular density revealed by synchrotron radiation microangiography and histologic analysis, (3) ameliorated the degree of myocardial ischemia as evidenced by myocardial lactate content and the extent of histologic necrosis, and (4) restored heart function as evidenced by increased ejection fraction (95% +/- 10%), reduced left ventricular end-diastolic pressure, and restored body weight. In vivo vascular endothelial growth factor 165 gene transfer promoted angiogenesis and was an effective approach to treating microvascular myocardial ischemia.
    Journal of Thoracic and Cardiovascular Surgery 11/2000; 120(4):720-8. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We examined whether transmyocardial revascularization (TMR) relieves myocardial ischemia by increasing regional perfusion via the transmural channels in acute canine experiments. Regional blood flow during transient coronary ligation (2 min) was compared before and 30 min after TMR, and at the third transient ischemia the mid-left ventricle (LV) was cut and immediately frozen along the short axis for the analysis of NADH fluorescence in the regions around the TMR channels. In low-resolution analysis (2-4 g tissue or 2-3 cm(2) area), regional perfusion was not significantly altered after TMR, and NADH fluorescence was observed throughout the ischemic region without significant spatial variation. High-resolution analysis (2.8 mg, 1 mm x 1 mm) revealed that the flow after TMR was lower, and NADH fluorescence was higher in the regions close to the channels (1-2 mm) than in the regions 3-4 mm away from them. Creating TMR channels did not improve the regional perfusion and rather aggravated the local ischemia in the vicinity of the channels in the immediate phase.
    AJP Heart and Circulatory Physiology 10/2000; 279(3):H1392-6. · 3.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We evaluated the vascular volume distribution with fine resolution (0.1-1.3 mg myocardial tissue) in the sagittal plane of the left ventricle by using the microsphere filling method in 21 dogs. The coronary arterial volume density in the sagittal plane did not exhibit normal distribution and was characterized by variability among the outer-to-inner layers and within the layers (+2SD/-2SD > 80 times), and the median values in the layers ranged from 4.7 to 22. 9 nl/mg myocardial tissue. The fractal analysis of vascular volume revealed a self-similar nature with a fractal dimension (D value) similar to that of flow distribution (1.20 +/- 0.05 and 1.24 +/- 0. 09 for vascular volume and flow distribution, respectively) and had a more marked variability than the flow. The correlation of the regional vascular volume between adjacent regions decreased as the distance increased. However, the correlation coefficients in the endocardial-to-epicardial direction were significantly higher than those in the anterior-to-posterior direction (P < 0.05 by paired t-test). In conclusion, we determined intramyocardial vascular volume density in the sagittal plane, and the distribution revealed considerable variability, self-similarity, and asymmetry in the correlation among the adjacent regions. These observations could be related to the characteristics of the intramural coronary vascular network.
    The American journal of physiology 01/2000; 277(6 Pt 2):H2353-62. · 3.28 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To clarify the pathophysiological cascade leading to lipopolysaccharide- (LPS) induced myocardial dysfunction, we measured sarcoplasmic reticulum (SR) function, expression of inducible nitric oxide synthase (iNOS), and left ventricular (LV) function in a rat whole heart model. The LV function was evaluated by peak LV pressure and SR function was evaluated by the mechanical restitution (MR) curve, a physiological parameter of SR function. The mechanical restitution curve was constructed by plotting extrasystolic potentiation of LV dP/dt during extrasystoles (100-700 ms) under fixed pacing. Functions were evaluated using the perfusion apparatus at 6 or 24 h after LPS administration. In the 6 h group, LV pressure was depressed to 62% of the control, the SR function was impaired, and iNOS protein was expressed. In the 24 h group LV pressure and SR function remained at the control levels, iNOS was not detected. In the 6 h group dexamethasone co-administration normalized the LPS effect and iNOS was not expressed. LPS-induced myocardial dysfunction appeared to be caused by impaired SR function and NO expression suggesting that NO may act as a trigger.
    Shock 06/1999; 11(5):362-6. · 2.61 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/1998; 31:285-285.