Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The tissue kallikrein-kinin system is present in the heart, and kinin has been shown to have cardioprotective effects. In this study, we investigated the potential role of tissue kallikrein in myocardial ischemia/reperfusion injury through adenovirus-mediated human kallikrein gene delivery. One week after gene delivery, the rats were subjected to a 30-minute coronary occlusion followed by a 2-hour reperfusion. Kallikrein gene delivery caused significant decreases in the ratio of infarct size to ischemic area at risk (from 69.6% to 44.5%, n=10 and 8, P<0.01) and in the incidence of ventricular fibrillation (from 64.3% to 16.7%, n=14 and 24, P<0.01) compared with the group injected with control adenovirus. Kallikrein gene delivery also attenuated programmed cell death in the ischemic area compared with the control area as assessed with the terminal deoxynucleotidyl transferase-mediated nick end labeling assay (n=6, P<0.01). Icatibant, a specific bradykinin B(2) receptor antagonist, abolished these kallikrein-mediated beneficial effects. The expression of human tissue kallikrein mRNA was identified in rat heart, kidney, lung, liver, and adrenal gland. After kallikrein gene delivery, cardiac kinin and cGMP levels were significantly elevated compared with the control (29.6+/-12.7 versus 6.1+/-2.1 pg/mg protein, n=7, P<0.01; 1.30+/-0.06 versus 0.86+/-0.09 pmol/mg protein, n=5, P<0.05). These results indicate that kallikrein gene delivery protects against myocardial infarction, ventricular arrhythmias, and apoptosis in ischemia/reperfusion injury via kinin-cGMP signal pathway. The successful application of this technology may have potential therapeutic value in the treatment of coronary artery diseases.
Hypertension 2000 Jan
PMID:Kallikrein gene delivery attenuates myocardial infarction and apoptosis after myocardial ischemia and reperfusion. 1064 70

We evaluated the effects of the kallikrein-kinin system on the proliferation and migration of primary cultured vascular smooth muscle cells (VSMCs) in vitro and neointima formation in balloon-injured rat carotid arteries in vivo. In cultured rat VSMCs, tissue kallikrein inhibited cell proliferation, and this inhibitory effect was blocked by Sar-Tyr-Aca(epsilon)-Lys [D-betaNal(7), Ile(8)]-des-Arg(9)-bradykinin, a bradykinin B(1) receptor antagonist, and by icatibant, a bradykinin B(2) receptor antagonist. Platelet-derived growth factor significantly increased the expression of the B(1) receptor but not the B(2) receptor in VSMCs. Platelet-derived growth factor-induced cell migration was significantly attenuated by des-Arg(9)-bradykinin and to a lesser degree by bradykinin. Endogenous B(1) receptor mRNA increased in rat carotid arteries after balloon angioplasty. After local delivery of adenovirus carrying the human tissue kallikrein gene into the rat carotid artery, we observed a 54% reduction in the intima/media ratio at the injured site compared with the control ratio (n=7, P:<0.01). Administration of the B(1) receptor antagonist via minipumps blocked the protective effect of kallikrein and partially reversed the intima/media ratio toward the control ratio. Kallikrein gene delivery results in the regeneration of endothelium compared with the control groups, and the B(1) receptor antagonist abolished this effect. Nitrite/nitrate, cGMP, and cAMP levels in balloon-injured arteries significantly increased after kallikrein gene delivery, whereas the B(1) receptor antagonist abolished these increases (n=4 or 5, P:<0.05). These results indicate that the B(1) receptor contributes to the reduction of neointima formation via the promotion of reendothelialization and inhibition of VSMC proliferation and migration through NO-cGMP and cAMP signaling pathways. This study provides significant implications in treating restenosis after revascularization.
Hypertension 2000 Sep
PMID:Bradykinin B(1) receptor mediates inhibition of neointima formation in rat artery after balloon angioplasty. 1098 66

Tissue kallikrein is a serine protease thought to be involved in the generation of bioactive peptide kinins in many organs like the kidneys, colon, salivary glands, pancreas, and blood vessels. Low renal synthesis and urinary excretion of tissue kallikrein have been repeatedly linked to hypertension in animals and humans, but the exact role of the protease in cardiovascular function has not been established largely because of the lack of specific inhibitors. This study demonstrates that mice lacking tissue kallikrein are unable to generate significant levels of kinins in most tissues and develop cardiovascular abnormalities early in adulthood despite normal blood pressure. The heart exhibits septum and posterior wall thinning and a tendency to dilatation resulting in reduced left ventricular mass. Cardiac function estimated in vivo and in vitro is decreased both under basal conditions and in response to beta-adrenergic stimulation. Furthermore, flow-induced vasodilatation is impaired in isolated perfused carotid arteries, which express, like the heart, low levels of the protease. These data show that tissue kallikrein is the main kinin-generating enzyme in vivo and that a functional kallikrein-kinin system is necessary for normal cardiac and arterial function in the mouse. They suggest that the kallikrein-kinin system could be involved in the development or progression of cardiovascular diseases.
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PMID:Cardiovascular abnormalities with normal blood pressure in tissue kallikrein-deficient mice. 1122 91

Angiogenesis represents a compensatory response targeted to preserve the integrity of tissues subjected to ischemia. The aim of the present study was to examine whether reparative angiogenesis is impaired in spontaneously hypertensive rats (SHR), as a function of progression of hypertension. In addition, the potential of gene therapy with human tissue kallikrein (HK) in revascularization was challenged in SHR and normotensive Wistar-Kyoto rats (WKY) that underwent excision of the left femoral artery. Expression of vascular endothelial growth factor and HK was upregulated in ischemic hindlimb of WKY but not of SHR. Capillary density was increased in ischemic adductor muscle of WKY (from 266+/-20 to 633+/-73 capillaries/mm(2) at 28 days, P<0.001), whereas it remained unchanged in SHR (from 276+/-20 to 354+/-48 capillaries/mm(2), P=NS), thus compromising perfusion recovery as indicated by reduced plantar blood flow ratio (0.61+/-0.08 versus 0.92+/-0.07 in WKY at 28 days, P<0.05). In separate experiments, saline or 5x10(9) pfu adenovirus containing the HK gene (Ad.CMV-cHK) or the beta-galactosidase gene (Ad.CMV-LacZ) was injected intramuscularly at 7 days after the induction of ischemia. Ad.CMV-cHK augmented capillary density and accelerated hemodynamic recovery in both strains, but these effects were more pronounced in SHR (P<0.01). Our results indicate that native angiogenic response to ischemia is impaired in SHR, possibly as a result of defective modulation of endothelial cell mitogens. Supplementation with kallikrein, one of the growth factors found to be deficient in SHR, restores physiological angiogenic response utilitarian for tissue healing. Our discoveries may have important implications in vascular medicine for therapeutic benefit.
Hypertension 2001 Jul
PMID:Rescue of impaired angiogenesis in spontaneously hypertensive rats by intramuscular human tissue kallikrein gene transfer. 1146 74

A transgenic rat line harboring the human tissue kallikrein gene was investigated for expression and activity of tonin and kallikrein in different regions of the brain. The introduction of the transgene into the rat genome produced a significant augmentation of the expression levels and activity of rat tissue kallikrein. The possibility that human kallikrein does not hydrolyze the rat substrate is probably responsible for the augmented expression of the rat enzyme. On the other hand, although expression of tonin was significantly reduced, tonin activity was not altered in most brain structures, except for cerebellum and neurohypophysis.
Hypertension 2002 Feb
PMID:Tonin and kallikrein in the brain of transgenic rat line expressing human tissue kallikrein. 1184 89

To clarify the role of the kallikrein-kinin system in cardiovascular homeostasis, the systemic and regional hemodynamics of kinin B2 receptor-deficient (B2-/-) and tissue kallikrein-deficient (TK-/-) mice were compared with their wild-type (WT) littermates on a pure C57BL/6 genetic background. B2-/-, TK-/-, and WT adult mice were normotensive and displayed normal hemodynamic (left ventricular [LV] pressure, cardiac output, total peripheral resistance, dP/dt(max)) and echocardiographic (septum and LV posterior wall thickness, LV diameter, LV mass, and LV fractional shortening) parameters. However, heart rate was lower in B2-/- mice compared with TK-/- and WT mice. In addition, B2-/- mice, but not TK-/- mice, exhibited lower coronary and renal blood flows and greater corresponding vascular resistances than did WT mice, indicating a tonic physiological vasodilating effect of bradykinin in these vascular beds. However, maximal coronary vasodilatation capacity, estimated after dipyridamole infusion, was similar in the 3 groups of mice. B2-/- mice were significantly more sensitive than were TK-/- mice to the vasoconstrictor effects of angiotensin II and norepinephrine. Finally, renin mRNA levels were significantly greater in B2-/- mice and smaller in TK-/- mice compared with WT mice. Taken together, these results indicate that under basal conditions, the kinin B2 receptor is not an important determinant of blood pressure in mice but is involved in the control of regional vascular tone in the coronaries and the kidneys. The phenotypic differences observed between TK-/- and B2-/- mice could be underlain by tissue kallikrein kinin-independent effect and/or kinin B1 receptor activation.
Hypertension 2002 Jul
PMID:Cardiovascular phenotypes of kinin B2 receptor- and tissue kallikrein-deficient mice. 1210 44

In this study, we used the somatic gene delivery approach to explore the role of the kallikrein-kinin system (KKS) in cardiac remodeling and apoptosis after myocardial infarction (MI). Rats were subjected to coronary artery ligation to induce MI, and adenovirus carrying the human tissue kallikrein or luciferase gene was injected into the tail vein at 1 week after surgery. Cardiac output gradually decreased from 2 to 6 weeks after MI, whereas delivery of the kallikrein gene prevented this decrease. Cardiac responses to dobutamine-induced stress were improved in rats receiving kallikrein gene as compared with rats receiving control virus at 6 weeks after MI. Kallikrein significantly improved cardiac remodeling by decreasing collagen density, cardiomyocyte size, and left ventricular internal perimeter and increasing capillary density in the heart at 6 weeks after MI. Kallikrein gene transfer attenuated myocardial apoptosis, which was positively correlated with remodeling parameters in the heart at 2 weeks after MI. Endothelial dysfunction, characterized by increased vascular resistance, decreased left ventricular blood flow, and decreased cardiac nitric oxide levels, existed in remodeled hearts at 2 weeks after MI, whereas kallikrein gene transfer improved these parameters. Kallikrein gene delivery improved cell survival parameters as shown by increased phospho-Akt and reduced caspase-3 activation at 2 weeks after MI. This study indicates that the kallikrein-kinin system plays an important role in preventing the progression of heart failure by attenuating cardiac hypertrophy and fibrosis, improving endothelial function, and inhibiting myocardial apoptosis through the Akt-mediated signaling pathway.
Hypertension 2002 Nov
PMID:Kallikrein gene delivery improves cardiac reserve and attenuates remodeling after myocardial infarction. 1241 58

Recently, therapeutic angiogenesis has been proposed as an alternative for the treatment of ischemic diseases unresponsive to conventional therapy. This strategy is based on the concept that a supply-side approach with growth factors would overcome the endogenous deficit and result in more robust collateralization. We have developed a strategy based on local delivery of human tissue kallikrein gene for potentiation of microcirculation and rescue of peripheral ischemia. Following successful application in otherwise healthy animals, the approach resulted to be of therapeutic value in rats with endothelial dysfunction caused by arterial hypertension. In addition, human tissue kallikrein prevents or rescues microvascular rarefaction caused by diabetes mellitus. In this model, human tissue kallikrein was able to stimulate vascular growth and contrast apoptosis. The strategy displays interesting pharmacological features because is devoid of obvious side effects and is effective even at low infecting doses. In addition, the neovascularization promoted by human tissue kallikrein is well organized and durable. It is reasonable to anticipate that the new approach will have a great impact in the treatment of cardiovascular ischemic complications.
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PMID:Human tissue kallikrein: a new bullet for the treatment of ischemia. 1257 Aug 6

We have examined whether exogenous human tissue kallikrein exerts pharmacological actions via the bradykinin B2 receptor; specifically, whether the protease can bind to, cleave, internalize, and/or activate a fusion protein composed of the rabbit B2 receptor conjugated to the green fluorescent protein (B2R-GFP). The enzyme partially digested the fusion protein at 1 micromol/L, but not 100 nmol/L, and promoted B2R-GFP endocytosis in HEK 293 cells (> or =50 nmol/L). Trypsin and endoproteinase Lys-C, but not plasma kallikrein, also cleaved B2R-GFP. Phospholipase A2 was activated by 50 nmol/L tissue kallikrein in HEK 293 cells expressing B2R-GFP, and this was mediated by the receptor, as shown by the effect of a B2 receptor antagonist and by the lack of response in untransfected cells. However, 500 nmol/L kallikrein elicited a strong receptor-independent activation of phospholipase A2. Tissue kallikrein competed for [3H]bradykinin binding to B2R-GFP only at 1 micromol/L. A simulation involving kallikrein treatment of HEK 293 cells, pretreated or not with human plasma, evidenced the formation of immunoreactive bradykinin. The enzyme (50 nmol/L) contracted the rabbit isolated jugular vein via its endogenous B2 receptors, but the effect was tachyphylactic, and there was no cross-desensitization with bradykinin effects. Aprotinin prevented all pharmacological responses to tissue kallikrein, indicating that the enzyme activity is required for its effect. The local generation of kinins is a plausible mechanism for the pharmacological effects of lower concentrations of tissue kallikrein (50 to 100 nmol/L); higher levels (0.5 to 1 micromol/L) can not only initiate the degradation of rabbit B2 receptors but also exert nonreceptor-mediated effects.
Hypertension 2003 Mar
PMID:Tissue kallikrein actions at the rabbit natural or recombinant kinin B2 receptors. 1283 33

Hypertension that results in left ventricular (LV) hypertrophy and/or fibrosis can lead to cardiac dysfunction. Spontaneously hypertensive rats (SHR) develop high blood pressure and LV hypertrophy at an early age and are a popular model of human essential hypertension. To investigate the role of the tissue kallikrein-kinin system in cardiac remodeling, an adenovirus containing the human tissue kallikrein gene was injected intravenously into adult SHR and normotensive Wistar-Kyoto (WKY) rats. The blood pressure of WKY rats remained unchanged throughout the experiment. Alternatively, kallikrein gene transfer reduced blood pressure in SHR for the first 2 wk, but had no effect from 3 to 5 wk. Five weeks after kallikrein gene delivery, SHR showed significant reductions in LV-to-heart weight ratio, LV long axis, and cardiomyocyte size; however, these parameters were unaffected in WKY rats. Interestingly, cardiac collagen density was decreased in both SHR and WKY rats receiving the kallikrein gene. Kallikrein gene transfer also increased cardiac capillary density in SHR, but not in WKY rats. The morphological changes after kallikrein gene transfer were associated with decreases in JNK activation as well as transforming growth factor (TGF)-beta 1 and plasminogen activator inhibitor-1 levels in the heart. In addition, kallikrein gene delivery elevated LV nitric oxide and cGMP levels in both rat strains. These results indicate that kallikrein-kinin attenuates cardiac hypertrophy and fibrosis and enhances capillary growth in SHR through the suppression of JNK, TGF-beta 1, and plasminogen activator inhibitor-1 via the nitric oxide-cGMP pathway.
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PMID:Kallikrein gene delivery attenuates cardiac remodeling and promotes neovascularization in spontaneously hypertensive rats. 1281 55


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