Inhibition of cellular ras prevents smooth muscle cell proliferation after vascular injury in vivo.

Proliferation of smooth muscle cells of the arterial wall in response to local injury is an important aetiologic factor of vascular proliferative disorders such as atherosclerosis and restenosis after angioplasty. Ras proteins are key transducers of mitogenic signals from membrane to nucleus in many cell types. We investigated the role of ras proteins in the vascular response to arterial injury by inactivating cellular ras of rats in which the common carotid artery was subjected to balloon injury. DNA vectors expressing ras transdominant negative mutants, which interfere with ras function, reduced neointimal formation after injury. Our results indicate a key role for ras in smooth muscle cell proliferation and show that the local delivery of transdominant negative mutants of ras in vivo might prevent some of the acute vascular injury caused by balloon injury.

Marrow-derived stromal cells express genes encoding a broad spectrum of arteriogenic cytokines and promote in vitro and in vivo arteriogenesis through paracrine mechanisms.

We recently demonstrated that marrow stromal cells (MSCs) augment collateral remodeling through release of several cytokines such as VEGF and bFGF rather than via cell incorporation into new or remodeling vessels. The present study was designed to characterize the full spectrum of cytokine genes expressed by MSCs and to further examine the role of paracrine mechanisms that underpin their therapeutic potential. Normal human MSCs were cultured under normoxic or hypoxic conditions for 72 hours. The gene expression profile of the cells was determined using Affymetrix GeneChips representing 12 000 genes. A wide array of arteriogenic cytokine genes were expressed at baseline, and several were induced >1.5-fold by hypoxic stress. The gene array data were confirmed using ELISA assays and immunoblotting of the MSC conditioned media (MSC(CM)). MSC(CM) promoted in vitro proliferation and migration of endothelial cells in a dose-dependent manner; anti-VEGF and anti-FGF antibodies only partially attenuated these effects. Similarly, MSC(CM) promoted smooth muscle cell proliferation and migration in a dose-dependent manner. Using a murine hindlimb ischemia model, murine MSC(CM) enhanced collateral flow recovery and remodeling, improved limb function, reduced the incidence of autoamputation, and attenuated muscle atrophy compared with control media. These data indicate that paracrine signaling is an important mediator of bone marrow cell therapy in tissue ischemia, and that cell incorporation into vessels is not a prerequisite for their effects.

Membrane-bound protein kinase A inhibits smooth muscle cell proliferation in vitro and in vivo by amplifying cAMP-protein kinase A signals.

cAMP-dependent protein kinase is anchored to discrete cellular compartments by a family of proteins, the A-kinase anchor proteins (AKAPs). We have investigated in vivo and in vitro the biological effects of the expression of a prototypic member of the family, AKAP75, on smooth muscle cells. In vitro expression of AKAP75 in smooth muscle cells stimulated cAMP-induced transcription, increased the levels of the cyclin-dependent kinase-2 inhibitor p27(kip1), and reduced cell proliferation. In vivo expression of exogenous AKAP75 in common carotid arteries, subjected to balloon injury, significantly increased the levels of p27(kip1) and inhibited neointimal hyperplasia. Both the effects in smooth muscle cells in vitro and in carotid arteries in vivo were specifically dependent on the amplification of cAMP-dependent protein kinase (PKA) signals by membrane-bound PKA, as indicated by selective loss of the AKAP75 biological effects in mutants defective in the PKA anchor domain or by suppression of AKAP effects by the PKA-specific protein kinase inhibitor. These data indicate that AKAP proteins selectively amplify cAMP-PKA signaling in vitro and in vivo and suggest a possible target for the inhibition of the neointimal hyperplasia after vascular injury.

Identification of phenotypes at risk of transition from diastolic hypertension to isolated systolic hypertension.

Little is known about the potential progression of hypertensive patients towards isolated systolic hypertension (ISH) and about the phenotypes associated with the development of this condition. Aim of this study was to detect predictors of evolution towards ISH in patients with initial systolic-diastolic hypertension. We selected 7801 hypertensive patients free of prevalent cardiovascular (CV) diseases or severe chronic kidney disease and with at least 6-month follow-up from the Campania Salute Network. During 55±44 months of follow-up, incidence of ISH was 21%. Patients with ISH at the follow-up were significantly older (P<0.0001), had longer duration of hypertension, higher prevalence of diabetes and were more likely to be women (all P<0.0001). They exhibited higher baseline left ventricular mass index (LVMi), arterial stiffness (pulse pressure/stroke index), relative wall thickness (RWT) and carotid intima-media thickness (IMT; all P<0.001). Independent predictors of incident ISH were older age (odds ratio (OR)=1.14/5 years), female gender (OR=1.30), higher baseline systolic blood pressure (OR=1.03/5 mm Hg), lower diastolic blood pressure (OR=0.89/5 mm Hg), longer duration of hypertension (OR=1.08/5 months), higher LVMi (OR=1.02/5 g m(-2.7)), arterial stiffness (OR=2.01), RWT (OR=1.02), IMT (OR=1.19 mm(-1); all P<0.0001), independently of antihypertensive treatment, obesity, diabetes and fasting glucose (P>0.05). Our findings suggest that ISH is a sign of aggravation of the atherosclerotic disease already evident by the target organ damage. Great efforts should be paid to prevent this evolution and prompt aggressive therapy for arterial hypertension should be issued before the onset of target organ damage, to reduce global CV risk.

Local delivery of marrow-derived stromal cells augments collateral perfusion through paracrine mechanisms.

BACKGROUND: Bone marrow cell therapy is reported to contribute to collateral formation through cell incorporation into new or remodeling vessels. However, the possible role of a paracrine contribution to this effect is less well characterized. METHODS AND RESULTS: Murine marrow-derived stromal cells (MSCs) were purified by magnetic bead separation of cultured bone marrow. The release of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and monocyte chemoattractant protein-1 (MCP-1) was demonstrated by analysis of MSC conditioned media (MSC-CM). MSC-CM enhanced proliferation of endothelial cells and smooth muscle cells in a dose-dependent manner; anti-VEGF and anti-FGF antibodies only partly attenuated these effects. Balb/C mice (n=10) underwent distal femoral artery ligation, followed by adductor muscle injection of 1x10(6) MSCs 24 hours later. Compared with controls injected with media (n=10) or mature endothelial cells (n=8), distal limb perfusion improved, and mid-thigh conductance vessels increased in number and total cross-sectional area. MSC injection improved limb function and appearance, reduced the incidence of auto-amputation, and attenuated muscle atrophy and fibrosis. After injection, labeled MSCs were seen dispersed between muscle fibers but were not seen incorporated into mature collaterals. Injection of MSCs increased adductor muscle levels of bFGF and VEGF protein compared with controls. Finally, colocalization of VEGF and transplanted MSCs within adductor tissue was demonstrated. CONCLUSIONS: MSCs secrete a wide array of arteriogenic cytokines. MSCs can contribute to collateral remodeling through paracrine mechanisms.

Effects of balloon injury on neointimal hyperplasia in streptozotocin-induced diabetes and in hyperinsulinemic nondiabetic pancreatic islet-transplanted rats.

BACKGROUND: The mechanisms of increased neointimal hyperplasia after coronary interventions in diabetic patients are still unknown. METHODS AND RESULTS: Glucose and insulin effects on in vitro vascular smooth muscle cell (VSMC) proliferation and migration were assessed. The effect of balloon injury on neointimal hyperplasia was studied in streptozotocin-induced diabetic rats with or without adjunct insulin therapy. To study the effect of balloon injury in nondiabetic rats with hyperinsulinemia, pancreatic islets were transplanted under the kidney capsule in normal rats. Glucose did not increase VSMC proliferation and migration in vitro. In contrast, insulin induced a significant increase in VSMC proliferation and migration in cell cultures. Furthermore, in VSMC culture, insulin increased MAPK activation. A reduction in neointimal hyperplasia was consistently documented after vascular injury in hyperglycemic streptozotocin-induced diabetic rats. Insulin therapy significantly increased neointimal hyperplasia in these rats. This effect of hyperinsulinemia was totally abolished by transfection on the arterial wall of the N17H-ras-negative mutant gene. Finally, after experimental balloon angioplasty in hyperinsulinemic nondiabetic islet-transplanted rats, a significant increase in neointimal hyperplasia was observed. CONCLUSIONS: In rats with streptozotocin-induced diabetes, balloon injury was not associated with an increase in neointimal formation. Exogenous insulin administration in diabetic rats and islet transplantation in nondiabetic rats increased both blood insulin levels and neointimal hyperplasia after balloon injury. Hyperinsulinemia through activation of the ras/MAPK pathway, rather than hyperglycemia per se, seems to be of crucial importance in determining the exaggerated neointimal hyperplasia after balloon angioplasty in diabetic animals.

Response to flecainide infusion predicts long-term success of hybrid pharmacologic and ablation therapy in patients with atrial fibrillation.

OBJECTIVES: We tested the hypothesis that the response to flecainide infusion can identify patients with atrial fibrillation (AF) in whom the hybrid pharmacologic and ablation therapy reduces the recurrences of AF. BACKGROUND: Infusion of class IC anti-arrhythmic drugs may promote transformation of AF into atrial flutter. Catheter ablation of atrial flutter has been demonstrated to be highly effective in preventing recurrences of atrial flutter. METHODS: Seventy-one consecutive patients with paroxysmal or chronic AF, in whom flecainide infusion (2 mg/kg body weight, intravenously) determined the transformation of AF into common atrial flutter (positive response), were randomized to receive one of the following treatments: oral pharmacologic treatment with flecainide (group A, n = 23); the hybrid treatment (catheter ablation of the inferior vena cava-tricuspid annulus isthmus, plus oral flecainide) (group B, n = 24); or catheter ablation of the isthmus only (group C, n = 24). Thirty-seven patients with a negative response to flecainide, who chose to be submitted to the hybrid treatment, were selected as the control group (group D). RESULTS: During a mean follow-up period of 24 +/- 7.2 months, the recurrences of AF and atrial flutter in group B (42%) were significantly lower than those in group A (78%, p < 0.001), group C (92%, p < 0.001) and group D (92%, p < 0.001). CONCLUSIONS: The creation of a complete bi-directional conduction block at the inferior vena cava-tricuspid annulus isthmus, plus flecainide administration, reduces the recurrences of both AF and atrial flutter in patients with class IC atrial flutter. Moreover, the early response to flecainide is safe and reliable in identifying patients who may benefit from this therapy.

Effects of hydroxymethylglutaryl coenzyme A reductase inhibitor simvastatin on smooth muscle cell proliferation in vitro and neointimal formation in vivo after vascular injury.

OBJECTIVES: We sought to evaluate the effects of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on vascular smooth muscle cell (VSMC) proliferation in vitro and neointimal formation in vivo after vascular injury. BACKGROUND: Neointimal hyperplasia after vascular injury is responsible for restenosis after arterial stenting, whereas arterial remodeling and neointimal formation are the causes of restenosis after percutaneous transluminal coronary angioplasty. METHODS: We assessed the effect of simvastatin on in vitro VSMC proliferation. To study the effects of simvastatin in vivo, balloon injury and stent deployment were performed in the common carotid artery of rats. Neointimal area was measured two weeks later in the balloon injury model and three weeks after stent deployment. RESULTS: Simvastatin markedly inhibits VSMC proliferation in vitro. In vivo, simvastatin reduced, in a dose-dependent manner, the neointimal area and the neointima-media ratio after balloon injury from 0.266 +/- 0.015 mm2 to 0.080 +/- 0.026 mm2 and from 1.271 +/- 0.074 to 0.436 +/- 0.158 (p < 0.001 vs. control rats) at the highest dose. Simvastatin also significantly reduced the neointimal formation and the neointima-media ratio after stenting from 0.508 +/- 0.035 mm2 to 0.362 +/- 0.047 mm2 (p < 0.05 vs. control rats) and from 2.000 +/- 0.136 to 1.374 +/- 0.180 (p < 0.05 vs. control rats). The vessel thrombosis rate after stent deployment was 30% in the control group and 11.1% in the treated group (p = NS). Moreover, the systemic administration of simvastatin did not affect hepatic and renal functions, blood pressure or heart rate. CONCLUSIONS: Simvastatin potently inhibits VSMC proliferation in vitro and reduces neointimal formation in a rat model of vascular injury.

8-chloro-cAMP inhibits smooth muscle cell proliferation in vitro and neointima formation induced by balloon injury in vivo.

OBJECTIVES: The aims of the present study were to assess 1) the effect of 8-C1-cAMP (cyclic-3'-5'-adenosine monophosphate) on vascular smooth muscle cell (VSMC) proliferation in vitro and 2) the efficacy of systemic administration of 8-C1-cAMP on neointimal formation after balloon injury in vivo. BACKGROUND: Neointimal formation after vascular injury is responsible for restenosis after arterial stenting. Recently, 8-C1-cAMP, a cAMP analogue that induces growth arrest, has been safely administered in phase I studies in humans. METHODS: The effect of 8-C1-cAMP on cell proliferation was first assessed on SMCs in vitro. To study the effects of cAMP in vivo, balloon injury was performed in 67 rats using a 2F Fogarty balloon catheter. RESULTS: The 8-C1-cAMP markedly inhibited VSMC proliferation in vitro, reduced protein kinase A (PKA) RIalpha subunit expression, and induced PKA RIIbeta subunit expression. In addition, 8-C1-cAMP reduced, in a dose-dependent manner, neointimal area and neointima/media ratio after balloon injury. The proliferative activity, assessed by proliferating nuclear cell antigen immunostaining, revealed a reduction of proliferative activity of VSMCs in vivo in the 8-C1-cAMP group. Moreover, the systemic administration of 8-C1-cAMP did not affect renal function, blood pressure and heart rate. CONCLUSIONS: We conclude that 8-C1-cAMP potently inhibits VSMC proliferation in vitro and reduces neointima formation by balloon injury in vivo after systemic administration. These data may have a clinical relevance in designing future strategies to prevent restenosis after arterial stenting and perhaps after percutaneous transluminal coronary angioplasty.

L-arginine administration reduces neointima formation after stent injury in rats by a nitric oxide-mediated mechanism.

The clinical outcome of vascular stenting is limited by in-stent stenosis. Increased nitric oxide (NO)/cGMP signaling by L-arginine (L-Arg) supplementation, the substrate for NO synthase (NOS), or NOS gene transfer may reduce in-stent neointima formation. After stenting, vascular cell proliferation in rat carotid arteries, as measured by 5'-bromodeoxyuridine (5'-BrdU) incorporation, indicated 15+/-8%, 28+/-5%, and 33+/-7% 5'-BrdU-positive vascular cells at 4, 7, and 14 days, respectively. Reporter beta-galactosidase gene transfer efficacy was evidenced by 30% beta-galactosidase-expressing medial smooth muscle cells at 14 days. The intima-to-media ratio (I/M) progressively increased to 2.32+/-0.24 at 14 days. To target in-stent neointima formation, animals were infected with adenoviral vectors (4x10(10) plaque-forming units per mL) expressing NOS2 (AdNOS2) or no transgene (AdRR5), or they received daily doses of L-Arg (500 mg. kg(-1). (d-1) IP). The neointima at 14 days was smaller in L-Arg-treated than in untreated rats (I/M 1.25+/-0.35 vs 2.32+/-0.24, P<0.05, n=7 each) or in AdRR5- and AdNOS2-infected rats (I/M 2.57+/-0.43, n=7 and 1.82+/-0.75, n=8, respectively; P<0.05 for both). The effect of L-Arg was abolished by simultaneous administration of N(G)-nitro L-arginine methyl ester, an NOS inhibitor (2.03+/-0.39, P<0.05, vs L-Arg). Inflammation was markedly less in L-Arg- and AdNOS2-treated than in AdRR5-infected rats. Supplemental L-Arg reduces neointima formation after stenting by way of an NOS-dependent mechanism and may be a valuable strategy to target in-stent stenosis.

A viral antigen-bearing cell line derived from culture of Paget's bone cells.

This study documents the characteristics of a viral antigen-bearing cell line derived from co-culture of the bone from a 71-year-old woman with Paget's disease of bone and HEp-2 cells. The cell line has survived in continuous culture for 3 1/2 years and 185 subcultures. The cells are epithelioid in appearance, produce alkaline and acid phosphatase, increase alkaline phosphatase activity in response to 1,25-(OH)2-D3 and contain receptors for 1,25-(OH)2-D3. Immunofluorescent studies utilizing antisera to respiratory syncytial virus and measles virus reveal antigens of both viruses in the cells. These cells do not produce bone in culture and the adenylate cyclase activity found in their plasma membrane does not increase significantly in response to parathyroid hormone or calcitonin. The cells are not contact inhibited and form spherical colonies in agarose. They are aneuploid and have a modal number of 62-74 as well as HeLa markers. When injected into athymic mice, osteosarcomas are produced. These tumors continue to bear viral antigens. The availability of this cell line should aid in further studies of the viral antigens associated with Paget's disease of bone.

Prognostic value of cardiac troponin I re-elevation following percutaneous coronary intervention in high-risk patients with acute coronary syndromes.

Troponin I is a predictive marker of short- and intermediate-term adverse cardiac events in patients with acute coronary syndromes (ACS). These high-risk patients may benefit from early percutaneous coronary intervention. However, whether additional myocardial injury, defined as postprocedural troponin I elevation, may be associated with adverse short- and intermediate-term outcomes has not been fully explored. Accordingly, we studied 132 consecutive patients with non-ST-elevation ACS (62% with non-Q-wave myocardial infarction) and elevated troponin I levels at admission (>0.15 ng/ml) who underwent percutaneous coronary intervention > or =48 hours after admission. Troponin I levels were routinely measured at 6 and 18 to 24 hours after intervention and patients were stratified according to the presence or absence of troponin I re-elevation, defined as postprocedural troponin I levels >1 times the admission levels. In-hospital and cumulative 6-month clinical outcomes were compared between groups. Patients with troponin I re-elevation (n = 51) were older (68 +/- 13 vs 64 +/- 12 years, p = 0.05) and had experienced prior myocardial infarction more frequently (92.5 vs 82.1, p = 0.09), but otherwise had similar baseline clinical characteristics. Patients with troponin I re-elevation had significantly higher in-hospital mortality (9.8% vs 0%, p = 0.016) and a higher 6-month cumulative death rate (24% vs 3.7%, p = 0.001). There was a trend for an increased 6-month myocardial infarction rate in patients with troponin I re-elevation (13.7% vs 3.7%, p = 0.11) and target vessel revascularization was similar between groups (16.7% vs 17.4%, p = 0.92). By multivariate analysis, troponin I re-elevation (odds ratio [OR] 6.2, p = 0.011) and diabetes mellitus (OR 5.7, p = 0.014) were the strongest independent predictors for increased 6-month cumulative mortality, whereas creatine kinase MB-fraction re-elevation had no prognostic value. We conclude that troponin I re-elevation after percutaneous coronary intervention in high-risk patients with ACS is associated with a substantial increase in mortality and reduced event-free survival at 6-month follow-up.

Troponin in acute coronary syndrome patients. The interventional cardiologist perspective.

Troponin measurement has now become an integral part of the assessment of patients with acute coronary syndromes (ACS). Obtaining troponin levels have been used effectively as a diagnostic tool with superior sensitivity and specificity compared to creatine kinase MB fraction in identifying high-risk ACS patients. The adverse prognosis of these high-risk patients can be modified by more aggressive treatment strategy including antiplatelet and antithrombotic therapy accompanied, if feasible, by early percutaneous intervention. The current review summarizes available data on troponin measurement as a clinical tool for tailoring therapeutic strategy in non-ST elevation ACS patients. In addition, the data on the potential predictive value of postintervention troponin levels is discussed.

Management of in-stent restenosis in peripheral arteries: are DEBs sufficient as stand-alone treatment for femoro-popliteal in-stent restenosis?

The treatment of in-stent restenosis (ISR) in the femoro-popliteal artery (FPA) is one of the major challenges of endovascular therapy, occurring in up to 40% of femoro-popliteal lesions treated with bare-metal stents within 1 year of treatment. Drug-eluting technologies, involving local delivery of paclitaxel, are providing a new paradigm for the treatment of ISR. Preliminary experience shows promising results compared to other techniques such as cutting balloon angioplasty and debulking strategies. Based on available data, drug-eluting balloons (DEBs) seem sufficient as stand-alone treatment of FPA-ISR. However, larger evidence from randomized studies is warranted to identify the clinical and/or anatomical setting in which they could fail.

Proximal endovascular occlusion for carotid artery stenting.

Carotid artery stenting (CAS) is considered to be an acceptable alternative to carotid endarterectomy (CEA), particularly in patients at increased risk for CEA. The safety of CAS has improved significantly over the past decade. Adjunctive use of embolic protection devices (EPDs), is thought to be partially responsible for the improved outcomes. Among these, proximal EPDs are based on the surgical principle of stopping or reversing flow by clamping the carotid arteries, much in the same way carotid endarterectomy accomplishes neuroprotection. This is achieved through external and common carotid clamping. A recent meta-analysis demonstrates that the use of proximal EPDs for neuroprotection in patients undergoing CAS is associated with a very low incidence of any strokes and composite MACCE at 30 days. This study also demonstrates that the excellent outcomes achieved using proximal EPDs are independent of patient gender, symptomatic status, and other baseline clinical characteristics including the presence of a contralateral carotid occlusion.

Does optical coherence tomography identify arterial healing after stenting? An in vivo comparison with histology, in a rabbit carotid model.

OBJECTIVE: To verify whether optical coherence tomography (OCT) can accurately monitor the occurrence of arterial healing after stenting. SETTING: Delayed stent endothelialisation may predispose to stent thrombosis. OCT is a high-resolution intravascular imaging technique that accurately identifies stent struts and arterial tissues. DESIGN AND INTERVENTIONS: Eight New Zealand white rabbits underwent the implantation of single bare metal stents (diameter 2-2.5 mm, length 8-13 mm) in the right common carotid artery through the external carotid artery. After a median of 11 days (range 2-28), the stented arteries were visualised by OCT, with images acquired at a pull-back speed of 0.5 mm/sec. The rabbits were then euthanised, vessels were formalin-fixed and finally processed for histopathology. RESULTS: We analysed 32 cross-sections from eight stented carotid arteries, for a total of 384 stent struts. OCT detected all of the stent struts in 30 of 32 cross-sections (93.7%), and correctly identified the presence/absence of tissue for every strut. Histological and OCT measurements of mean neointima thickness (0.135 (SD 0.079) mm and 0.145 (SD 0.085) mm, respectively, p = NS) were similar and closely related (r = 0.85, p<0.001). Neointima area progressively increased with longer time intervals from stent deployment to sacrifice; histological and OCT measurements were similar for each time interval. The intra-observer and interobserver reproducibility of OCT neointima measurements were excellent (R2 = 0.90 and 0.88, respectively). CONCLUSIONS: OCT is a promising means for monitoring stent strut coverage and vessel wall healing in vivo, the relevance of which will become even more significant with the increasing use of drug-eluting stents.

Excimer laser in acute myocardial infarction: single centre experience on 66 patients.

BACKGROUND: Pulsed-wave ultraviolet excimer laser light at 308 nm can vaporise thrombus, suppress platelet aggregation, and, unlike other thrombectomy devices, ablates the underlying plaque. AIM: To evaluate both safety and efficacy of laser ablation in patients presenting with Acute Myocardial Infarction (AMI) complicated by persistent thrombotic occlusion. METHODS: From May 2003 to October 2006, we enrolled 66 AMI patients (age 59+/-11 years; 57 men) presenting complete thrombotic occlusion of the infarct related vessel. All patients were treated with laser. Primary acute angiographic end-points was corrected TIMI frame count. Secondary echocardiographic end-point was left ventricular remodeling defined as an increase in end-diastolic volume >/=20% 6 months after infarction. Tertiary clinical endpoint was event-free survival at 6 months follow-up. RESULTS: There were no intra-procedural death or coronary perforation. One primary angiographic failure was observed during lasing. Major dissection occurred in 1 (1.5%) and distal embolization in 4 patients (6%). Corrected TIMI frame count was 100 at baseline, 29+/-0.6 after lasing and 22+/-3 after stenting. At 6-months follow-up, left ventricular remodeling occurred in 8% patients. Event-free survival was 95% at 6-months follow-up. CONCLUSION: Laser angioplasty is feasible, safe and effective for the challenging treatment of patients with AMI and thrombus-laden lesions. The acute effects on coronary epicardial and myocardial reperfusion are excellent.

Mechanisms of restenosis after angioplasty and approach to therapy (Review).

Angioplasty is a principal treatment for occlusive vascular disease but 30-50% of patients show a restenosis of the vessel. There is no clinical effective therapy for this disease. It has been demonstrated, in animal models, that various drugs such as NO-donor, plasminogen inhibitor tranexamic acid and MMP (matrix metalloproteinases) reduce the rate of restenosis. Other therapeutic approaches are cytotoxic therapy, and strategies to inhibit cell cycle progression. Systemic administration of conventional pharmacologic agents inhibit cell cycle kinases and vascular lesion formation in animal models. As cell cycle progression is accompanied by fluctuations in the concentration of adenosine 3',5-monophospate (cAMP) and in the activity of the cAMP dependent protein kinase (PKA), local administration of cAMP and phospodiesterase-inhibitor drugs (aminophylline or amrinone) markedly inhibit neointima formation. The successful use of local radiation therapy to inhibit neointima formation after vascular injury may reflect a similar combination of cell-cycle arrest and vascular cell apoptosis. The most effective therapy for occlusive vascular disease will likely combine intravascular stenting with an antiproliferative therapy.

Evidence for both respiratory syncytial virus and measles virus antigens in the osteoclasts of patients with Paget's disease of bone.

Recent ultrastructural and immunohistochemical evidence supports the hypothesis that Paget's disease of bone is a slow viral infection of the Paramyxoviridae family. Conflicting evidence for the presence of respiratory syncytial virus (RSV), a pneumovirus, or measles, a morbillivirus, has been reported. By the indirect fluorescent antibody assay, four RSV antisera were compared with four measles antisera on serial sections of pagetic bone or replicate coverslips of cells from pagetic bone grown in culture from 30 patients. Results produced positive immunofluorescence for RSV in 28 of 29 patients and positive immunofluorescence for measles in 11 of 22 patients. Of the 20 patients from whom comparable samples could be tested for antigens, 11 were found to harbor both antigens. These studies support the hypothesis that Paget's disease of bone is a slow viral infection of the Paramyxoviridae family more closely related to the pneumoviruses than the morbilliviruses.

[Gene therapy for the treatment of restenosis after coronary angioplasty]. / Terapia genica per il trattamento della ristenosi dopo angioplastica coronarica.

Accumulation and proliferation of vascular smooth muscle cells are associated with atherosclerosis and hypertension. Proliferation of smooth muscle cells constitutes a major pathological event responsible for long-term failure of coronary and peripheral arterial bypass graft as well as the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The incidence of restenosis after PTCA has been reported to be as high as 40-45% within 3-6 months. Major advantages in recombinant deoxyribonucleic acid (DNA) technology and eukaryotic gene regulation allow to hypothesize gene therapy as a potential treatment for inherited and acquired diseases. Gene therapy is the introduction of genes into somatic cells to correct an inherited or acquired disorder through the synthesis of missing or defective protein. Although no disease has yet been treated by gene therapy, several gene transfer protocols have recently been undertaken. We have studied the expression of foreign DNA that has been introduced into smooth muscle cells after balloon carotid injury in a rat model of angioplasty. The effects of different degree of balloon injury on neointima formation and c-fos expression was also assessed. Our data demonstrate that site-specific gene expression can be achieved by direct gene transfer in vivo and could be applied to the treatment of restenosis after PTCA.