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Paul W M Fedak

Publications and source records attributed to Paul W M Fedak.

At least 19 recordsLinked to original sources
PubMed2006

Integrin-linked kinase expression is elevated in human cardiac hypertrophy and induces hypertrophy in transgenic mice.

BACKGROUND: Although numerous signaling pathways are known to be activated in experimental cardiac hypertrophy, the molecular basis of the hypertrophic response inherent in human heart diseases remains largely unknown. Integrin-linked kinase (ILK) is a multifunctional protein kinase that physically links beta-integrins with the actin cytoskeleton, suggesting a potential mechanoreceptor role. METHODS AND RESULTS: Here, we show a marked increase in ILK protein levels in hypertrophic ventricles of patients with congenital and acquired outflow tract obstruction. This increase in ILK was associated with activation of the Rho family guanine triphosphatases, Rac1 and Cdc42, and known hypertrophic signaling kinases, including extracellular signal-related kinases (ERK1/2) and p70 S6 kinase. Transgenic mice with cardiac-specific expression of a constitutively active ILK (ILK(S343D)) or wild-type ILK (ILK(WT)) exhibited a compensated ventricular hypertrophic phenotype and displayed an activation profile of guanine triphosphatases and downstream protein kinases concordant with that seen in human hypertrophy. In contrast, transgenic mice with cardiomyocyte-restricted expression of a kinase-inactive ILK (ILK(R211A)) were unable to mount a compensatory hypertrophic response to angiotensin II in vivo. CONCLUSIONS: Taken together, these results identify ILK-regulated signaling as a broadly adaptive hypertrophic response mechanism relevant to a wide range of clinical heart disease.

Alanine↗
PubMed2006

C-reactive protein alters antioxidant defenses and promotes apoptosis in endothelial progenitor cells.

OBJECTIVE: C-reactive protein (CRP) has been suggested to participate in the development of atherosclerosis, in part, by promoting endothelial dysfunction and impairing endothelial progenitor cell (EPC) survival and differentiation. In the present study, we evaluated the effects of CRP on antioxidative enzymes, reactive oxygen species production, telomerase activity, and apoptosis in human circulating EPCs. METHODS AND RESULTS: EPCs, isolated from peripheral venous blood, were cultured in the absence or presence of native pentameric azide and lipopolysaccharide (LPS)-free CRP (0, 5, 15, and 20 microg/mL), N-acetylcysteine (NAC), hydrogen peroxide (H2O2) or monoclonal anti-CRP antibodies. Fluorescence-activated cell sorter (FACS) analysis was used for the measurement of intracellular H2O2 and superoxide (O2(-)) by loading cells with 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA). Apoptosis was evaluated with Annexin V immunostaining and cytosolic cytochrome c expression. Western blot analysis was used for the determination of manganese superoxide dismutase (MnSOD) and glutathione peroxidase expression, and polymerase chain reaction enzyme-linked immunosorbent assay was used to assess telomerase activity. Incubation of EPCs with CRP caused a concentration dependent increase in reactive oxygen species (ROS) production and apoptosis, with an effect quantitatively similar to H2O2. This effect was attenuated during coincubation with NAC or anti-CRP antibodies. Furthermore, CRP altered EPC antioxidative enzyme levels, demonstrating a reduced expression of glutathione peroxidase and a significant increase in MnSOD expression. Transfection of EPCs with MnSOD-RNAi resulted in a reduction in CRP-induced ROS production, apoptosis, and telomerase inactivation. CONCLUSIONS: CRP, at concentrations known to predict cardiovascular events, may serve to impair EPC antioxidant defenses, and promote EPC sensitivity toward oxidant-mediated apoptosis and telomerase inactivation. These data further support a direct role of CRP in the development and/or progression of atherothrombosis.

Acetylcysteine↗
PubMed2006

Stem cell factor deficiency is vasculoprotective: unraveling a new therapeutic potential of imatinib mesylate.

Evidence suggests that bone marrow (BM) cells may give rise to a significant proportion of smooth muscle cells (SMCs) that contribute to intimal hyperplasia after vascular injury; however, the molecular pathways involved and the timeline of these events remain poorly characterized. We hypothesized that the stem cell factor (SCF)/c-Kit tyrosine kinase signaling pathway is critical to neointimal formation by BM-derived progenitors. Wire-induced femoral artery injury in mice reconstituted with wild-type BM cells expressing yellow fluorescent protein was performed, which revealed that 66+/-12% of the SMCs (alpha-smooth muscle actin-positive [alphaSMA(+)] cells) in the neointima were from BM. To characterize the role of the SCF/c-Kit pathway, we used c-Kit deficient W/W(v) and SCF-deficient Steel-Dickie mice. Strikingly, vascular injury in these mice resulted in almost a complete inhibition of neointimal formation, whereas wild-type BM reconstitution of c-Kit mutant mice led to neointimal formation in a similar fashion as wild-type animals, as did chronic administration of SCF in matrix metalloproteinase-9-deficient mice, a model of soluble SCF deficiency. Pharmacological antagonism of the SCF/c-Kit pathway with imatinib mesylate (Gleevec) or ACK2 (c-Kit antibody) also resulted in a marked reduction in intimal hyperplasia. Vascular injury resulted in the local upregulation of SCF expression. c-Kit(+) progenitor cells (PCs) homed to the injured vascular wall and differentiated into alphaSMA(+) cells. Vascular injury also caused an increase in circulating SCF levels which promoted CD34(+) PC mobilization, a response that was blunted in mutant and imatinib mesylate-treated mice. In vitro, SCF promoted adhesion of BM PCs to fibronectin. Additionally, anti-SCF antibodies inhibited adhesion of BM PCs to activated SMCs and diminished SMC differentiation. These data indicate that SCF/c-Kit signaling plays a pivotal role in the development of neointima by BM-derived PCs and that the inhibition of this pathway may serve as a novel therapeutic target to limit aberrant vascular remodeling.

Animals↗
PubMed2006

C-Reactive protein upregulates receptor for advanced glycation end products expression in human endothelial cells.

The receptor for advanced glycation end products (RAGE) may play an important role in inflammatory processes and endothelial activation, likely to accelerate the processes of coronary atherosclerotic development, especially in diabetic patients. The factors that regulate arterial expression of RAGE are not completely clear. C-reactive protein (CRP) is identified as a key proinflammatory cytokine in patients with atherosclerosis. Therefore, we tested the hypothesis that RAGE expression in endothelial cells can be upregulated by CRP. Human saphenous vein endothelial cells were incubated with human recombinant CRP, free of sodium azide and endotoxin. RAGE protein expression was measured by flow-cytometric analysis and Western blotting. CRP caused a significant increase in RAGE protein expression at a dose as low as 5 mug/mL, with expression peaking at 24 to 48 hours after CRP incubation. The effects of modified monomeric CRP on RAGE protein expression were comparable with that of native pentameric CRP. At the mRNA level, CRP not only increased RAGE gene expression but also attenuated the degradation of RAGE mRNA. Furthermore, RNA interference of RAGE gene expression significantly decreased the level of macrophage chemoattractant protein 1, a key downstream mediator of CRP activity. Therefore, CRP at concentrations known to predict future vascular events upregulates RAGE expression in human endothelial cells at both the protein and mRNA level. Silencing of the RAGE gene prevents CRP-induced macrophage chemoattractant protein 1 activation. These data reinforce the mechanistic links among inflammation, endothelial dysfunction, and atherothrombosis.

C-Reactive Protein↗
PubMed2006

Altered expression of disintegrin metalloproteinases and their inhibitor in human dilated cardiomyopathy.

BACKGROUND: Disintegrin metalloproteinases (ADAMs) may contribute to structural cardiac remodeling by altering cell-surface matrix receptors (integrins) and activating potent biomolecules. We compared expression of ADAMs, their endogenous inhibitor tissue inhibitor of metalloproteinases (TIMP)-3, and integrins in human heart tissue with varied patterns of structural remodeling. METHODS AND RESULTS: Myocardium was obtained from patients with dilated cardiomyopathy (n=20), hypertrophic obstructive cardiomyopathy (n=5), and nonfailing donor hearts (n=7). Paired samples (n=10) were obtained before left ventricular assist device insertion and at transplantation. The expressions of ADAM10, ADAM12, ADAM15, and ADAM17, TIMP-3, and integrin receptors beta1D and beta3 were determined by quantitative immunoblotting. Integrin shedding was assessed by the ratio of integrin cleavage products to intact protein abundance. Confocal microscopy was performed. Dilated cardiomyopathy was characterized by increased ADAM10 and ADAM15 expression and reduced TIMP-3 expression. The integrin beta1D cleavage ratio was elevated, indicating receptor shedding. ADAM10 and ADAM15 expressions correlated with the cleavage ratio. ADAM10 colocalized with integrin beta1D by confocal microscopy. ADAM10 expression correlated with clinical indices of chamber dilatation and systolic dysfunction. Hemodynamic unloading reduced ADAM10 and ADAM12 expressions and increased integrin beta1D expression. ADAM12 and integrin beta1D expressions were increased in HOCM. ADAM17 was increased in both dilated cardiomyopathy and hypertrophic obstructive cardiomyopathy. CONCLUSIONS: Disintegrin metalloproteinases are differentially expressed in human myocardium, reflecting the underlying pattern of structural remodeling. ADAM10 and ADAM15 may contribute to cardiac dilatation by reducing cell-matrix interactions via integrin shedding. Targeting disintegrin metalloproteinases, perhaps by restoring deficient TIMP-3 levels with gene or cell-based therapies, may prevent progressive chamber dilatation in human dilated cardiomyopathy.

ADAM Proteins↗
PubMed2005

Cell transplantation preserves matrix homeostasis: a novel paracrine mechanism.

OBJECTIVES: Cell transplantation prevents chamber dilatation, but the underlying molecular mechanisms remain undefined. Structural cardiac remodeling involves matrix degradation from an imbalance of matrix metalloproteinases (MMP) relative to endogenous tissue inhibitors of metalloproteinases (TIMP). We aimed to determine the capacity of cell transplantation to alter extracellular matrix in the failing heart and, in so doing, identify novel paracrine molecular mediators underlying the beneficial effects of cell transplantation on chamber dilatation. METHODS: Smooth muscle cells were transplanted to the dilating left ventricle of cardiomyopathic hamsters (CTX, n = 15) compared with age-matched media-injected cardiomyopathic (CON, n = 15) and normal hamsters (n = 7). After 5 weeks, left ventricular volume was measured by computerized planimetry. Fibrillar collagen was examined by confocal microscopy. Matrix homeostasis was quantified by measuring MMP/TIMP expression/activity relative to myocardial collagen synthesis (14C-proline uptake). RESULTS: Left ventricular dilatation was attenuated in CTX hearts (P = .02). CTX restored perimysial collagen fiber content and architecture to normal levels. TIMP-2 and TIMP-3 expression were enhanced in CTX (TIMP-2, 195% +/- 42% of CON, P = .02; TIMP-3, 118% +/- 3% of CON, P = .002), and correspondingly, gelatinase MMP-2 activity was reduced (P < .05). The TIMP:MMP ratio was increased in CTX hearts (TIMP-2 to MMP-2, 410% +/- 134% of CON, P = .04, and TIMP-3 to MMP-9, 205% +/- 47% of CON, P = .03), reflecting a reduced capacity for matrix degradation. Collagen synthesis was equivalent (CTX vs CON), suggesting that restored matrix architecture was a function of attenuated matrix degradation. CONCLUSIONS: These data provide the first evidence that cell transplantation limits ventricular dilatation in the failing heart through a paracrine-mediated mechanism that preserves extracellular matrix homeostasis.

Animals↗
PubMed2005

Cell transplantation preserves cardiac function after infarction by infarct stabilization: augmentation by stem cell factor.

OBJECTIVE: We hypothesized that implantation of adult mesenchymal stem cells after acute myocardial infarction mobilizes bone marrow precursor cells by activating the stem cell factor pathway, and that overdriving this pathway would enhance the beneficial effects of cell transplantation. METHODS: After coronary ligation, medium, mesenchymal stem cells, or stem cell factor-overproducing mesenchymal stem cells were injected into the anterior left ventricle. Cells from beta-galactosidase transgenic mice enabled tracking of injected cells. The global and local impact of the cells was evaluated by measuring cytokine levels, endothelial progenitor cells, and myocardial angiogenesis, and by addressing cardiomyogenesis with confocal microscopy. The impact on cardiac function was evaluated by pressure-volume loops. Ventricular morphometrics were measured after in situ perfusion-fixation of the hearts at physiologic pressures. RESULTS: Implantation of mesenchymal stem cells increased myocardial stem cell factor levels 2.0-fold, endothelial progenitor cell mobilization 2.7-fold, and myocardial angiogenesis 2.3-fold (P < .05), but did not induce mitogenesis in host cardiomyocytes or give rise to beta-galactosidase-expressing cardiomyocytes. Cell-transplanted groups had improved indices of cardiac function, including preload recruitable stroke work and end-systolic elastance (P < .001). Cell transplantation resulted in 2.0-fold smaller ventricular volumes (P = .001) and 2.0-fold reduced infarct scar area (P = .056), but had no effect on the volume of spared myocardium. Stem cell factor overproduction imparted greater functional benefit without inducing detectable histologic cardiomyocyte regeneration. CONCLUSION: Mesenchymal stem cell implantation after myocardial infarction facilitates functional cardiac regeneration without myocyte regeneration through augmentation of endogenous infarct repair, which is enhanced by stem cell factor.

Animals↗
PubMed2005

Tetrahydrobiopterin deficiency exaggerates intimal hyperplasia after vascular injury.

Decreased levels of tetrahydrobiopterin (BH4), an absolute cofactor for nitric oxide synthase (NOS), lead to uncoupling of NOS into a superoxide v. nitric oxide producing enzyme, and it is this uncoupling that links it to the development of vascular disease. However, the effects of in vivo deficiency of BH4 on neointimal formation after vascular injury have not been previously investigated. Hph-1 mice, which display 90% deficiency in guanine triphosphate cyclohydrolase I, the rate limiting enzyme in BH4 synthesis, were used. Hph-1 and wild-type mice, treated with either vehicle or BH4 (n = 15 per group), were subjected to wire-induced femoral artery injury, and NOS expression and activity, inflammation, cell proliferation, superoxide production, and neointimal formation were assessed. The major form of NOS expressed over vessel wall after vascular injury was endothelial NOS. Hph-1 mice exhibited lower NOS activity (2.8 +/- 0.3 vs. 4.5 +/- 0.4 pmol/min/mg protein, P < 0.01), and higher aortic superoxide content (5.2 +/- 2.0 x 10(5) cpm vs. 1.6 +/- 0.7 x 10(5) cpm, P < 0.01) compared with wild-type controls, indicating uncoupling of NOS. Treatment of hph-1 mice with BH4 significantly increased NOS activity (from 2.8 +/- 0.3 to 4.1 +/- 0.4 pmol.min(-1).mg protein(-1), P < 0.05), and attenuated superoxide production (from 5.2 +/- 2.0 x 10(5) cpm to 0.8 +/- 0.7 x 10(5) cpm, P < 0.05). Hph-1 mice also had higher inflammatory reactions and more cell proliferation after vascular injury. Furthermore, hph-1 mice responded by a marked increase in neointimal formation at 4 wk after vascular injury, compared with wild-type controls (intima:media ratio: 4.5 +/- 0.5 vs. wild-type 0.7 +/- 0.1, P < 0.001). Treatment of hph-1 mice with BH4 prevented vascular injury-induced increase in neointimal formation (intima:media ratio: 1.4 +/- 0.1 vs. hph-1, P < 0.001). Treatment had no effect on wild-type controls. In summary, we describe, for the first time, that in vivo BH4 deficiency facilitates neointimal formation after vascular injury. Modulation of BH4 bioavailability is an important therapeutic target for restenosis.

Animals↗
PubMed2005

Combined endothelial and myocardial protection by endothelin antagonism enhances transplant allograft preservation.

BACKGROUND: Endothelin is a potent inflammatory peptide associated with myocardial dysfunction, coronary vasculopathy, and reduced survival after cardiac transplantation. We hypothesized that endothelin antagonism during cardiac allograft storage would limit early endothelial dysfunction and improve myocardial performance after transplantation. METHODS: Porcine orthotopic transplantations (n = 16) were performed after 6 hours of ischemic storage. Intermittent donor blood perfusion (control, n = 8) was compared with donor blood perfusion enhanced with 100 micromol/L of an endothelin receptor blocker (n = 8). Left ventricular performance was assessed after caval occlusion with a Millar micromanometer and conductance catheter. Coronary endothelial function was assessed in vitro with a macrovascular tissue bath apparatus. Myocardial endothelin, tumor necrosis factor alpha, and transforming growth factor beta protein expression were determined. Oxidative stress was inferred on the basis of 8-isoprostane levels, and myocardial metabolism was inferred on the basis of the extraction or production of oxygen, acid, and lactate by the heart. RESULTS: Endothelial function was diminished 48 hours after transplantation but not earlier. Endothelin receptor blocker treatment during preservation limited coronary endothelial dysfunction 48 hours after reperfusion ( P = .001). Weaning from cardiopulmonary bypass and left ventricular performance after transplantation was improved in endothelin receptor blocker-treated hearts (P = .02). Myocardial endothelin expression was equivalent in both groups and increased during reperfusion after transplantation (P = .001). Tumor necrosis factor alpha levels decreased with endothelin receptor blocker treatment (P = .02), whereas transforming growth factor beta levels did not change (P = .86). 8-Isoprostane, oxygen, acid, and lactate levels were similar, suggesting that oxidative stress and metabolism were not important mechanisms of benefit. CONCLUSIONS: Endothelin accumulates during allograft storage and contributes to endothelial and myocardial dysfunction after transplantation. Endothelin blockade during allograft preservation limits endothelial injury and enhances ventricular recovery after transplantation.

Animals↗
PubMed2005

Bicuspid aortic valve disease: recent insights in pathophysiology and treatment.

Bicuspid aortic valve is a common congenital cardiac malformation with a broad spectrum of clinical outcomes. Bicuspid aortic valve may go undetected throughout an individual's lifetime or, alternatively, they may have devastating clinical consequences, resulting in death. Both clinicians and medical scientists have taken a renewed interest in the development, pathophysiology and treatment options for this subtle but often substantial clinical entity. Evidence is mounting to suggest that an underlying disease of the aorta is inherited with bicuspid aortic valve, although considerable controversy surrounds this theory. Novel molecular mechanisms underlying the valve and vascular pathologies, as well as new surgical therapies for these patients have been proposed in the past 10 years.

Aortic Valve↗
PubMed2004

Enhanced IGF-1 expression improves smooth muscle cell engraftment after cell transplantation.

The functional benefit of cell transplantation after a myocardial infarction is diminished by early cell losses. IGF-1 enhances cell proliferation and survival. We hypothesized that IGF-1-transfected smooth muscle cells (SMCs) would enhance cell survival and improve engraftment after cell transplantation. The IGF-1 gene was transfected into male SMCs and compared with SMCs transfected with a plasmid vector (vector control) and nontransfected SMCs (cell control). IGF-1 mRNA (n=10/group) and protein levels (n=6/group) were higher (P <0.05 for all groups) at 3, 7, and 14 days compared with controls. VEGF was also increased in parallel to enhanced IGF-1 expression. IGF-1-transfected cells demonstrated greater cell proliferation, stimulated angiogenesis, and decreased caspase-3 activity after simulated ischemia and reperfusion (P <0.05 for all groups compared with vector or cell controls). A uniform left ventricular injury was produced in female rats using a cryoprobe. Three weeks later, 2 x 10(6) cells from three groups were implanted into the scar. One week later, IGF-1-transfected SMCs had increased myocardial IGF-1 and VEGF levels, increased Bcl2 expression, limited cell apoptosis, and enhanced vessel formation in the myocardial scar compared with the two control groups (P <0.05 for all groups). The proportion of SMCs surviving in the implanted region was greater (P <0.05) in the IGF-1-transfected group than in the vector or cell controls. Gene enhancement with IGF-1 improved donor cell proliferation, survival, and engraftment after cell transplantation, perhaps mediated by enhanced angiogenesis and reduced apoptosis.

Animals↗
PubMed2004

TIMP-3 deficiency leads to dilated cardiomyopathy.

BACKGROUND: Despite the mounting clinical burden of heart failure, the biomolecules that control myocardial tissue remodeling are poorly understood. TIMP-3 is an endogenous inhibitor of matrix metalloproteinases (MMPs) that has been found to be deficient in failing human myocardium. We hypothesized that TIMP-3 expression prevents maladaptive tissue remodeling in the heart, and accordingly, its deficiency in mice would alone be sufficient to trigger progressive cardiac remodeling and dysfunction similar to human heart failure. METHODS AND RESULTS: Mice with a targeted timp-3 deficiency were evaluated with aging and compared with age-matched wild-type littermates. Loss of timp-3 function triggered spontaneous LV dilatation, cardiomyocyte hypertrophy, and contractile dysfunction at 21 months of age consistent with human dilated cardiomyopathy. Its absence also resulted in interstitial matrix disruption with elevated MMP-9 activity, and activation of the proinflammatory tumor necrosis factor-alpha cytokine system, molecular hallmarks of human myocardial remodeling. CONCLUSIONS: TIMP-3 deficiency disrupts matrix homeostasis and the balance of inflammatory mediators, eliciting the transition to cardiac dilation and dysfunction. Therapeutic restoration of myocardial TIMP-3 may provide a novel approach to limit cardiac remodeling and the progression to failure in patients with dilated cardiomyopathy.

ADAM Proteins↗
PubMed2004

Novel cardioprotective effects of pravastatin in human ventricular cardiomyocytes subjected to hypoxia and reoxygenation: beneficial effects of statins independent of endothelial cells.

Cardioprotective strategies are needed to prevent perioperative myocardial dysfunction in high-risk patients undergoing cardiac surgery. Despite accumulating evidence that statins exert lipid-independent cardioprotective effects, these have been ascribed primarily to improvements in endothelial function and neutrophil-endothelial interaction. The direct effects of statins on cardiomyocytes (independent of endothelial cells) remain unknown. Using a well-characterized model of low-volume hypoxia and reoxygenation, we studied the effects of pravastatin on human ventricular cardiomyocytes. Cardiomyocytes were subjected to 90 min of low-volume hypoxia and 30 min of reoxygenation in the presence and absence of pravastatin (1, 10, and 100 microm) (n = 10 per group). In some experiments, the effects of endothelin (ET) receptor blockade (with bosentan) and nitric oxide synthase (NOS) inhibition (with L-NAME) on pravastatin-mediated cardioprotection were evaluated. Cell survival, NO, and ET-1 production and protein kinase Akt activation were determined. Pravastatin treatment prevented cardiomyocyte cell death following simulated hypoxia and reoxygenation (P < 0.01). This effect was mediated via an increase in NO release, decrease in myocyte ET-1 production/action, and an increase in protein kinase Akt activation. We demonstrate, for the first time, novel protective effects of pravastatin in human ventricular cardiomyocytes independent of endothelial cells or other cell types. Statin therapy may restore ischemic hearts to full functional integrity during cardioplegic arrest through a direct effect on cardiomyocyte survival.

Acyl Coenzyme A↗
PubMed2004

C-reactive protein attenuates endothelial progenitor cell survival, differentiation, and function: further evidence of a mechanistic link between C-reactive protein and cardiovascular disease.

BACKGROUND: Myocardial ischemia provides a potent stimulus to angiogenesis, and the mobilization and differentiation of endothelial progenitor cells (EPCs) has been shown to be important in this process. An elevated level of C-reactive protein (CRP) has emerged as one of the most powerful predictors of cardiovascular disease. However, the impact of CRP on EPC biology is unknown. METHODS AND RESULTS: EPCs were isolated from the peripheral venous blood of healthy male volunteers. Cells were cultured in endothelial cell basal medium-2 in the absence and presence of CRP (5 to 20 microg/mL), rosiglitazone (1 micromol/L), and/or vascular endothelial growth factor. EPC differentiation, survival, and function were assayed. CRP at concentrations > or =15 microg/mL significantly reduced EPC cell number, inhibited the expression of the endothelial cell-specific markers Tie-2, EC-lectin, and VE-cadherin, significantly increased EPC apoptosis, and impaired EPC-induced angiogenesis. EPC-induced angiogenesis was dependent on the presence of nitric oxide, and CRP treatment caused a decrease in endothelial nitric oxide synthase mRNA expression by EPCs. However, all of these detrimental CRP-mediated effects on EPCs were attenuated by pretreatment with rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist. CONCLUSIONS: Human recombinant CRP, at concentrations known to predict adverse vascular outcomes, directly inhibits EPC differentiation, survival, and function, key components of angiogenesis and the response to chronic ischemia. This occurs in part via an effect of CRP to reduce EPC eNOS expression. The PPARgamma agonist rosiglitazone inhibits the negative effects of CRP on EPC biology. The ability of CRP to inhibit EPC differentiation and survival may represent an important mechanism that further links inflammation to cardiovascular disease.

Apoptosis↗
PubMed2004

Rosiglitazone facilitates angiogenic progenitor cell differentiation toward endothelial lineage: a new paradigm in glitazone pleiotropy.

BACKGROUND: Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists inhibit vascular smooth muscle proliferation and migration and improve endothelial function. It is unknown whether PPAR-gamma agonists favorably modulate bone marrow (BM)-derived angiogenic progenitor cells (APCs) to promote endothelial lineage differentiation and early reendothelialization after vascular intervention. METHODS AND RESULTS: C57/BL6 mice, treated with or without rosiglitazone (8 mg/kg per day), a PPAR-gamma agonist, underwent femoral angioplasty. Rosiglitazone treatment attenuated neointimal formation (intima/media ratio: 0.98+/-0.12 [rosiglitazone] versus 3.1+/-0.5 [control]; P<0.001; n=10 per group). Using a BM transplantation model, we identified that 58+/-12% of the cells within the neointima at 4 weeks were derived from the BM. Pure endothelial marker-positive, pure alpha-smooth muscle actin (alphaSMA)-positive, or double-positive APCs could be found both in mouse BM and in human peripheral blood after culture in conditional medium enriched with vascular endothelial growth factor. Rosiglitazone caused a 6-fold (P<0.001) increase in colony formation by human endothelial progenitor cells, promoted the differentiation of APCs toward the endothelial lineage in mouse BM in vivo (0.66+/-0.06% [control] to 0.95+/-0.08% [rosiglitazone]; P<0.05) and in human peripheral blood in vitro (13.2+/-1.5% [control] to 28.4+/-3.3% [rosiglitazone]; P<0.05), and inhibited the differentiation toward the smooth muscle cell lineage. Within the neointima, rosiglitazone also stimulated APCs to differentiate into mature endothelial cells and caused earlier reendothelialization compared with controls (31+/-5 versus 8+/-2 CD31-positive cells per millimeter of neointimal surface on day 14; P<0.01). CONCLUSIONS: Similar to embryonic stem cell-derived progenitors, the adult BM and peripheral blood harbor APCs that are at least bipotential and able to differentiate into endothelial and smooth muscle lineages. The PPAR-gamma agonist rosiglitazone promotes the differentiation of these APCs toward the endothelial lineage and attenuates restenosis after angioplasty.

Angioplasty↗
PubMed2004

C-reactive protein upregulates complement-inhibitory factors in endothelial cells.

BACKGROUND: Because complement-mediated vascular injury participates in atherosclerosis and C-reactive protein (CRP) can activate the complement cascade, we sought to determine whether CRP affects the expression of the protective complement-inhibitory factors on the cell surface of endothelial cells (ECs). METHODS AND RESULTS: Human coronary artery or human saphenous vein ECs were incubated with CRP (0 to 100 microg/mL, 0 to 72 hours), and the expression of the complement-inhibitory proteins decay-accelerating factor (DAF), membrane cofactor protein (CD46), and CD59 were measured by flow cytometry. Incubation with CRP resulted in a significant increase in the expression of all 3 proteins. CRP-induced upregulation of DAF required increased steady-state mRNA and de novo protein synthesis. The increased expression of complement-inhibitory proteins was functionally effective, resulting in significant reduction of complement-mediated lysis of antibody-coated human saphenous vein ECs. CONCLUSIONS: These observations provide evidence for a possible protective role for CRP in atherogenesis.

Antibody-Dependent Cell Cytotoxicity↗