Development and validation of risk prediction models for multiple cardiovascular diseases and Type 2 diabetes.

Accurate risk assessment of an individuals' propensity to develop cardiovascular diseases (CVDs) is crucial for the prevention of these conditions. Numerous published risk prediction models used for CVD risk assessment are based on conventional risk factors and include only a limited number of biomarkers. The addition of novel biomarkers can boost the discriminative ability of risk prediction models for CVDs with different pathogenesis. The present study reports the development of risk prediction models for a range of heterogeneous CVDs, including coronary artery disease (CAD), stroke, deep vein thrombosis (DVT), and abdominal aortic aneurysm (AAA), as well as for Type 2 diabetes mellitus (DM2), a major CVD risk factor. In addition to conventional risk factors, the models incorporate various blood biomarkers and comorbidities to improve both individual and population stratification. An automatic variable selection approach was developed to generate the best set of explanatory variables for each model from the initial panel of risk factors. In total, up to 254,220 UK Biobank participants (ranging from 215,269 to 254,220 for different CVDs and DM2) were included in the analyses. The derived prediction models utilizing Cox proportional hazards regression achieved consistent discrimination performance (C-index) for all diseases: CAD, 0.794 (95% CI, 0.787-0.801); DM2, 0.909 (95% CI, 0.903-0.916); stroke, 0.778 (95% CI, 0.756-0.801); DVT, 0.743 (95% CI, 0.737-0.749); and AAA, 0.893 (95% CI, 0.874-0.912). When validated on various subpopulations, they demonstrated higher discrimination in healthier and middle-age individuals. In general, calibration of a five-year risk of developing the CVDs and DM2 demonstrated incremental overestimation of disease-related conditions amongst the highest decile of risk probabilities. In summary, the risk prediction models described were validated with high discrimination and good calibration for several CVDs and DM2. These models incorporate multiple shared predictor variables and may be integrated into a single platform to enhance clinical stratification to impact health outcomes.

Impaired perfusion after myocardial infarction is due to reperfusion-induced deltaPKC-mediated myocardial damage.

OBJECTIVE: To improve myocardial flow during reperfusion after acute myocardial infarction and to elucidate the molecular and cellular basis that impedes it. According to the AHA/ACC recommendation, an ideal reperfusion treatment in patients with acute myocardial infarction (AMI) should not only focus on restoring flow in the occluded artery, but should aim to reduce microvascular damage to improve blood flow in the infarcted myocardium. METHODS: Transgenic mouse hearts expressing the deltaPKC (protein kinase C) inhibitor, deltaV1-1, in their myocytes only were treated with or without the deltaPKC inhibitor after ischemia in an ex vivo AMI model. deltaV1-1 or vehicle was also delivered at reperfusion in an in vivo porcine model of AMI. Microvascular dysfunction was assessed by physiological and histological measurements. RESULTS: deltaPKC inhibition in the endothelial cells improved myocardial perfusion in the transgenic mice. In the porcine in vivo AMI model, coronary flow reserve (CFR), which is impaired for 6 days following infarction, was improved immediately following a one-minute treatment at the end of the ischemic period with the deltaPKC-selective inhibitor, deltaV1-1 ( approximately 250 ng/kg), and was completely corrected by 24 h. Myocardial contrast echocardiography, electron microscopy studies, and TUNEL staining demonstrated deltaPKC-mediated microvascular damage. epsilonPKC-induced preconditioning, which also reduces infarct size by >60%, did not improve microvascular function. CONCLUSIONS: These data suggest that deltaPKC activation in the microvasculature impairs blood flow in the infarcted tissue after restoring flow in the occluded artery and that AMI patients with no-reflow may therefore benefit from treatment with a deltaPKC inhibitor given in conjunction with removal of the coronary occlusion.

Arteriotomy closure device application following percutaneous coronary intervention may prevent bleeding complications in patients with acute myocardial infarction.

The current study was performed to determine whether application of arteriotomy closure devices (ACDs) affect bleeding complications as compared to manual compression in patients with ST-elevated acute myocardial infarction (STEMI) who undergo primary or rescue percutaneous intervention (PCI). 314 consecutive cases of STEMI treated with PCI were retrospectively evaluated. Overall, 82.8% of patients received ACDs with total bleeding rate of 4.2% vs. 11.1% in patients who had manual compression, p=0.042. This difference in bleeding rates did not correlate with any clinical characteristic or utilization of GPIIb/IIIa inhibitors. Accordingly, ACDs can improve the acute results of PCI in STEMI patients.

Long-term histopathologic and IVUS evaluations of a novel coiled sheet stent in porcine carotid arteries.

Carotid angioplasty with stent placement has been proposed as an alternative method for revascularization of carotid artery stenosis. A novel stent with a laser-cut, rolled sheet of Nitinol (EndoTex Interventional Systems, Inc., Cupertino, CA) has been developed to customize treatment of stenotic lesions in carotid arteries utilizing a single stent, designed to adapt to multiple diameters and to tapered or nontapered configurations. The purpose of this study is to evaluate the conformability and vascular response to a novel stent in a chronic porcine carotid model using serial three-dimensional intravascular ultrasound (IVUS) analysis as well as histological examination. Ten Yucatan pigs underwent stent implantation in both normal carotid arteries with adjunctive balloon angioplasty. Three-dimensional IVUS analysis was performed before stent implantation, after adjunctive balloon angioplasty, and at follow-up [1 month (n = 6), 3 months (n = 6), or 6 months (n = 8)]. Histological examination (injury score, percent plaque obstruction, and qualitative analysis) was also performed. All stents were successfully deployed and well apposed in different sized vessels (lumen area range: 19-30 mm(2)). Volumetric IVUS analysis showed no significant difference between the lumen areas before stent implantation and after adjunctive balloon angioplasty and no stent area change at each follow-up point compared to immediately postprocedure. Histological examination revealed minimal injury and neointimal hyperplasia at each follow-up point. In the chronic porcine carotid model, the novel stent system demonstrated good conformability, resulting in minimal vessel injury and neointimal formation.

Augmentation of tissue perfusion by a novel compression device increases neurologically intact survival in a porcine model of prolonged cardiac arrest.

OBJECTIVE: This study was performed to determine the potential efficacy of an automated device with a load-distributing band (AutoPulse, Revivant Corporation), in improving neurologically intact survival after cardiac arrest. DESIGN: Randomized, controlled trial. SETTING: University animal laboratory. SUBJECTS: Forty-four swine (18-23 kg). INTERVENTIONS: Eight minutes after induction of untreated ventricular fibrillation, pigs were randomized to AutoPulse-CPR (A-CPR, n = 22), conventional cardiopulmonary resuscitation (CPR) with 20% anterior-posterior chest displacement (C-CPR20, n = 10) or 30% chest displacement (C-CPR30, n = 12), followed by resuscitation protocol with ventilation, defibrillation and intravenous epinephrine (adrenaline). MEASUREMENTS AND MAIN RESULTS: Aortic and right atrium blood pressure was measured with micromanometers. Regional blood flows were measured with microspheres. Coronary perfusion pressure during A-CPR was significantly higher as compared to C-CPR without epinephrine (A-CPR versus C-CPR20 versus C-CPR30; 16 +/- 1 mmHg versus 7 +/- 2 mmHg versus 11 +/- 2 mmHg, p < 0.05). A-CPR improved both myocardial flow without epinephrine (A-CPR versus C-CPR20 versus C-CPR30; 23% versus 0% versus 4%; percent of baseline, p < 0.05) and cerebral blood flow (40% versus 4% versus 19%, percent of baseline, p < 0.05). Sixteen of 22 animals receiving A-CPR regained spontaneous circulation and survived; 14/22 had normal cerebral performance (CPC 1). Four of 12 animals receiving C-CPR30 regained spontaneous circulation and survived, but only one animal had normal neurological function (14/22 versus 1/12, p < 0.0001). No animal receiving C-CPR20 achieved spontaneous circulation. At necropsy, 67% of C-CPR30 had rib fracture and 33% showed lung injury, while A-CPR and C-CPR20 resulted in no detectable injuries. CONCLUSIONS: Improved hemodynamics with AutoPulse performed CPR results in improved neurologically intact survival without subsequent thoracic or pulmonary injuries in this porcine model of prolonged cardiac arrest.

The conversion in application of percutaneous coronary intervention following the introduction of drug eluting stents.

In order to determine the changes in the pattern of techniques applied during elective coronary intervention, data from 688 patients prior to Sirolimus. Drug-Eluting Stents (DES) approval was compared to 438 patients who underwent coronary intervention after DES approval. There was increased intervention to higher risk lesions, including smaller vessels and re-stenotic lesions after DES approval. Total number of stents per patient significantly decreased, despite longer stent length per patient or per lesion after DES approval. No significant difference was found in multivessel interventions.

Transendocardial and transepicardial intramyocardial fibroblast growth factor-2 administration: myocardial and tissue distribution.

Effective local delivery to the heart remains an obstacle to successful therapeutic application of a number of drugs and biological agents. This study was designed to study and optimize the delivery characteristics of transendocardial intramyocardial (IM) administration, determine myocardial deposition and retention over time, and compare it to transepicardial IM injection. Thirty-nine pigs were used for the study (15 for catheter optimization, 15 for transendocardial IM delivery, and 9 for transepicardial IM delivery). (125)I-Fibroblast growth factor-2 (FGF2) (25 microCi) was used as the prototype molecule. Tissue and myocardial distribution was determined at 1 and 24 h and 7 days. Using 1-h (125)I-FGF2 myocardial deposition as a parameter for delivery efficiency, the optimal needle length and delivery volume for transendocardial based delivery were determined to be 6 mm and 0.1 ml, respectively. Using these parameters for endocardial delivery, (125)I-FGF2 cardiac activity was 18.01 +/- 3.84% of delivered activity at 1 h, 11.65 +/- 5.17% at 24 h, and 2.32 +/- 0.87% at 7 days in ischemic animals. Studies in nonischemic animals produced similar results. For transepicardial delivery, (125)I-FGF2 cardiac-specific activity was 23.14 +/- 12.67% for the 6-mm needle, declining to 12.32 +/- 8.50% at 24 h, and did not significantly differ from values obtained following transendocardial delivery. Thus, optimized transendocardial intramyocardial delivery using Biosense guidance results in efficient delivery of FGF2 to the target myocardium that is comparable with transepicardial delivery, both providing markedly higher myocardial deposition and retention and lower systemic recirculation of FGF2 than intracoronary, intrapericardial, or intravenous delivery. However, myocardial distribution is limited to injection sites.

Risk factors for the development of retroperitoneal hematoma after percutaneous coronary intervention in the era of glycoprotein IIb/IIIa inhibitors and vascular closure devices.

OBJECTIVES: We sought to determine the incidence, clinical features, and risk factors for retroperitoneal hematoma (RPH) after percutaneous coronary intervention (PCI). BACKGROUND: Little is known about the clinical features, outcomes, and determinants of this serious complication in the contemporary era of PCI. METHODS: A retrospective analysis yielded 26 cases of RPH out of 3,508 consecutive patients undergoing PCI between January 2000 and January 2004. Cases were compared with a randomly selected sample of 50 control subjects without RPH. RESULTS: The incidence of RPH was 0.74%. Features of RPH included abdominal pain (42%), groin pain (46%), back pain (23%), diaphoresis (58%), bradycardia (31%), and hypotension (92%). The mean systolic blood pressure nadir was 75 mm Hg. The hematocrit dropped by 11.5 +/- 5.1 points from baseline in RPH patients, as compared with 2.3 +/- 3.3 points in controls (p < 0.0001). The mean hospital stay was longer in RPH patients (2.9 +/- 3.8 days vs. 1.7 +/- 1.5 days, p = 0.06). The following variables were found to be independent predictors of RPH: female gender (odds ratio [OR] 5.4, p = 0.005), low body surface area (BSA <1.73 m(2); OR 7.1, p = 0.008), and higher femoral artery puncture (OR 5.3, p = 0.013). There was no association between RPH and arterial sheath size, use of glycoprotein IIb/IIIa inhibitors, or deployment of a vascular closure device. CONCLUSIONS: Female gender, low BSA, and higher femoral artery puncture are significant risk factors for RPH. Awareness of the determinants and clinical features of RPH may aid in prevention, early recognition, and prompt treatment.

Novel percutaneous adventitial drug delivery system for regional vascular treatment.

A novel intracoronary microsyringe system (MicroSyringe) was developed for regulated drug injection into the adventitial space. In this report, the feasibility, safety, and distribution pattern of vascular treatment with this modality were tested in 17 swine by delivering Oregon green-labeled paclitaxel (OGP) and tacrolimus. Coronaries were harvested 0.5-96 hr postinjection and analyzed for drug by fluorescence histochemistry (OGP) and liquid chromatography-mass spectrometry (tacrolimus). Histopathological analysis was subsequently performed. The microsyringe deliveries were performed safely in all cases. In the OGP-injected group, within 2 hr postprocedure there was intense staining of the adventitia, media, and endothelium around the injection site, and by 23 hr staining extended distally by 27.5 mm. With tacrolimus, similar longitudinal drug distribution was seen; furthermore, by 48 hr there was detectable drug over 40 mm proximal and distal to the injection site. Significant levels of tacrolimus were detectable in coronaries at 96 hr. Percutaneous adventitial delivery is safe, feasible, and provides consistent dosing for complete treatment of a vascular territory.

Initial experience with the novel 6 Fr-compatible system for debulking de novo coronary arterial lesions.

The purpose of this study was to determine the efficacy of a novel system for debulking of de novo native coronary arterial lesions. The Helixciser De Novo system is a novel 6 Fr-compatible catheter with a cutter encased in a slotted-orifice housing to excise atheromatous plaque. The cutter rotates at 15,000 rpm, debulking the plaque as it tracks through the lesion over a straight wire or a self-expanding nitinol helical-shaped wire. The tissue is aspirated via an Archimedes screw pump to vacuum collection chamber. The device was evaluated in a porcine toxic coronary stent model of chronic occlusion and in five patients with focal de novo native coronary arterial lesions. Procedural variables along with outcomes were reviewed. Quantitative angiography (QCA) and volumetric intravascular ultrasound (IVUS) analysis were performed. In a porcine model of chronic occlusion, QCA demonstrated pretreatment minimal lumen diameter (MLD) increased from 0.77 +/- 0.59 to 1.88 +/- 0.25 mm postdebulking. IVUS analysis demonstrated pretreatment lumen volume (LV) increased from 15.8 +/- 22.2 to 46.4 +/- 28.9 mm(3) postdebulking. In human clinical feasibility cases, QCA demonstrated pretreatment MLD increased from 0.96 +/- 0.40 to 2.04 +/- 0.19 mm postdebulking. IVUS analysis demonstrated pretreatment LV increased from 38.40 +/- 12.78 to 52.05 +/- 15.68 mm(3) postdebulking. Preliminary results document the feasibility of Helixcision De Novo for treatment of focal de novo native coronary arterial lesions. Quantitative angiographic and IVUS analysis indicate that this system can effectively debulk plaque from selected noncalcified atherosclerotic lesions and thus may represent an alternative treatment strategy for coronary artery disease.

Stent implantation for coronary aneurysm with edge stenosis: angiographic and intravascular analysis.

The incidence of coronary artery aneurysms is about 1 to 2%, with clinical course dependent on the size of the aneurysm. A case of moderate-size aneurysm in the proximal left anterior descending coronary artery with stenosis at both edges is presented. This was interrogated with intravascular ultrasound (IVUS), and based on the patient's presentation, a single stent, size-matched 1:1 to the proximal reference, was placed across the aneurysm and both lesions. Post-implantation IVUS demonstrated residual stenosis and minimal change in the neck size of the aneurysm. At 4 months, there was no thrombosis or in-stent restenosis, and the aneurysm was almost completely resolved.

Evaluation of high-pressure retrograde coronary venous delivery of FGF-2 protein.

Delivery of angiogenic factors to ischemic myocardium remains a practical challenge. We evaluated the efficiency and efficacy of delivery of fibroblast growth factor-2 (FGF-2) protein via high-pressure retrograde injection into the anterior interventricular vein (AIV) in a porcine model of chronic myocardial ischemia. Labeled FGF-2 protein was delivered to the myocardium of three pigs via the AIV and the left anterior descending (LAD) coronary artery in three others. At 1 hr, the amount of protein in the left ventricle and the LAD region was quantified. Copper stents were implanted in the LAD of 25 pigs, resulting in chronic myocardial ischemia. At 4 weeks, microsphere-derived myocardial blood flow was assessed at rest and during pacing. In eight pigs (AIV FGF), FGF-2 protein (6 microg/kg) was delivered via high-pressure retrograde injection into the AIV. Six pigs (intracoronary FGF) received the same amount of FGF-2 by intracoronary delivery. Five pigs (AIV saline) received a placebo injection into the AIV and six pigs (control) served as controls. Four weeks later, myocardial blood flow was reassessed. At 1 hr, significantly more FGF remained in the left ventricle (1.3 vs. 0.82 microg; P < 0.04) and in the LAD region (1.2 vs. 0.64 microg; P = 0.03) after AIV compared to intracoronary delivery. Four weeks after treatment, resting LAD blood flow (normalized to right ventricular flow) improved slightly in the AIV FGF and intracoronary FGF arms (1.32-1.37 for both; P = 0.11), while it decreased significantly in the AIV saline (1.32-1.23; P = 0.02) and the control arms (1.32-1.19; P = 0.0004). Pacing LAD blood flow decreased significantly in the control arm (1.30-1.23; P < 0.05), but did not change significantly in the other three arms. High-pressure retrograde injection into the AIV may represent an efficient and effective means for delivering angiogenic factors to ischemic myocardium.

Early experience with a novel plaque excision system for the treatment of complex coronary lesions.

The use of directional coronary atherectomy (DCA) in current practice has been limited. The SilverHawk System is a newly developed plaque excision device that aims to overcome the drawbacks of prior DCA platforms. The device was evaluated in a porcine coronary model and in a series of patients. Procedural variables along with outcomes were reviewed. Quantitative angiography (QCA) was performed and excised tissue fragments were weighed and examined histologically. In porcine cases, pretreatment MLD increased from 0.51 +/- 0.26 to 2.36 +/- 0.59 mm postdebulking and 19.9 +/- 7.6 mg of tissue was retrieved. In human cases, pretreatment MLD increased from 0.8 +/- 0.4 to 2.2 +/- 0.5 mm postdebulking and 15.2 +/- 7.8 mg of tissue was retrieved without complications. These data show that the SilverHawk System may offer significant utility in treating a wide variety of complex coronary lesions.

Inhibition of delta-protein kinase C protects against reperfusion injury of the ischemic heart in vivo.

BACKGROUND: Current treatment for acute myocardial infarction (AMI) focuses on reestablishing blood flow (reperfusion). Paradoxically, reperfusion itself may cause additional injury to the heart. We previously found that delta-protein kinase C (deltaPKC) inhibition during simulated ischemia/reperfusion in isolated rat hearts is cardioprotective. We focus here on the role for deltaPKC during reperfusion only, using an in vivo porcine model of AMI. METHODS AND RESULTS: An intracoronary application of a selective deltaPKC inhibitor to the heart at the time of reperfusion reduced infarct size, improved cardiac function, inhibited troponin T release, and reduced apoptosis. Using 31P NMR in isolated perfused mouse hearts, we found a faster recovery of ATP levels in hearts treated with the deltaPKC inhibitor during reperfusion only. CONCLUSIONS: Reperfusion injury after cardiac ischemia is mediated, at least in part, by deltaPKC activation. This study suggests that including a deltaPKC inhibitor at reperfusion may improve the outcome for patients with AMI.

Simultaneous assessment of fractional and coronary flow reserves in cardiac transplant recipients: Physiologic Investigation for Transplant Arteriopathy (PITA Study).

BACKGROUND: The utility of measuring fractional flow reserve (FFR) to assess cardiac transplant arteriopathy has not been evaluated. Measuring coronary flow reserve (CFR) as well as FFR could add information about the microcirculation, but until recently, this has required two coronary wires. We evaluated a new method for simultaneously measuring FFR and CFR with a single wire to investigate transplant arteriopathy. METHODS AND RESULTS: In 53 cases of asymptomatic cardiac transplant recipients without angiographically significant coronary disease, FFR and thermodilution-derived CFR (CFRthermo) were measured simultaneously with the same coronary pressure wire in the left anterior descending artery and compared with volumetric intravascular ultrasound (IVUS) imaging. The average FFR was 0.88+/-0.07; in 75% of cases, the FFR was less than the normal threshold of 0.94; and in 15% of cases, the FFR was < or =0.80, the upper boundary of the gray zone of the ischemic threshold. There was a significant inverse correlation between FFR and IVUS-derived measures of plaque burden, including percent plaque volume (r=0.55, P<0.0001). The average CFRthermo was 2.5+/-1.2; in 47% of cases, CFRthermo was < or =2.0. In 14%, the FFR was normal (> or =0.94) and the CFR was abnormal (<2.0), suggesting predominant microcirculatory dysfunction. CONCLUSIONS: FFR correlates with IVUS findings and is abnormal in a significant proportion of asymptomatic cardiac transplant patients with normal angiograms. Simultaneous measurement of CFR with the same pressure wire, with the use of a novel coronary thermodilution technique, is feasible and adds information to the physiological evaluation of these patients.

Adjunctive platelet glycoprotein IIb/IIIa receptor inhibition with tirofiban before primary angioplasty improves angiographic outcomes: results of the TIrofiban Given in the Emergency Room before Primary Angioplasty (TIGER-PA) pilot trial.

BACKGROUND: Previous work has suggested that platelet glycoprotein IIb/IIIa receptor blockade may confer benefit in the treatment of acute myocardial infarction. The TIGER-PA pilot trial was a single-center randomized study to evaluate the safety, feasibility, and utility of early tirofiban administration before planned primary angioplasty in patients presenting with acute myocardial infarction. METHODS AND RESULTS: A total of 100 patients presenting with acute myocardial infarction were randomized to either early administration of tirofiban in the emergency room or later administration in the catheterization laboratory. The primary outcome measures were initial TIMI grade flow, corrected TIMI frame counts, and TIMI grade myocardial perfusion ("blush"). Thirty-day major adverse cardiac events were also assessed. Angiographic outcomes demonstrate a significant improvement in initial TIMI grade flow, corrected TIMI frame counts, and TIMI grade myocardial perfusion when patients are given tirofiban in the emergency room before primary angioplasty. The rate of 30-day major adverse cardiac events suggests that early administration may be beneficial. CONCLUSIONS: This pilot study suggests that early administration of tirofiban improves angiographic outcomes and is safe and feasible in patients undergoing primary angioplasty for acute myocardial infarction.

Intrapericardial administration of basic fibroblast growth factor: myocardial and tissue distribution and comparison with intracoronary and intravenous administration.

Growth factor-induced angiogenesis is being investigated in ischemic heart disease. Intracoronary and intravenous delivery are the most practical, but are limited by low myocardial uptake and significant systemic recirculation. The pericardial space may act as a drug delivery reservoir with increased myocardial uptake and reduced systemic toxicities. This study was designed to investigate the myocardial and tissue deposition and retention of basic fibroblast growth factor (FGF-2) after intrapericardial administration in normal and chronically ischemic animals. Twelve Yorkshire pigs were used for the study [six normal and six animals with chronic myocardial ischemia (ameroid constrictor on LCx)] with bolus intrapericardial administration of (125)I-FGF-2 (25 micro Ci) with 30 micro g of cold FGF-2 and 3 mg of heparin. Tissue and myocardial distribution was determined at 1 and 24 hr by measuring (125)I-bFGF-specific activity. In addition, regional myocardial deposition was determined using (125)I-bFGF activity and organ level autoradiography. The heart (pericardium and myocardium) accounted for the majority of (125)I-bFGF activity in ischemic animals (30.9% at 1 hr and 23.9% at 24 hr). Left anterior descending artery territory activity/gm of tissue for nonischemic and ischemic animals was 0.01% and 0.01% at 1 hr and 0.0009% and 0.12% at 24 hr, respectively. LCx territory activity for nonischemic and ischemic animals was 0.006% and 0.008% at 1 hr and 0.03% and 0.05% at 24 hr, respectively. Endocardial activity was low at all time points. Liver uptake was 0.47% (nonischemic) and 0.34% (ischemic) at 1 hr and 0.23% (nonischemic) and 0.54% (ischemic) at 24 hr. Intrapericardial delivery of FGF-2 provides markedly higher myocardial deposition and retention and lower systemic recirculation than intracoronary or intravenous delivery at the expense of poor subendocardial penetration. This limitation, however, did not affect its efficacy.

Del1 mediates VSMC adhesion, migration, and proliferation through interaction with integrin alpha(v)beta(3).

Del1 is a matrix protein transiently expressed by embryonic endothelial cells. It was recently demonstrated that vascular endothelial cells adhere and interact with Del1 through alpha(v)beta(3)- integrins, providing an autocrine angiogenic signaling pathway in this cell type. To determine whether Del1 might signal to other cell types in the vessel wall in a paracrine fashion, studies were conducted with vascular smooth muscle cells (VSMC). Del1 promoted adhesion and migration of VSMC in a dose-dependent fashion. These functions were mediated through alpha(v)beta(3)-integrins, as the vitronectin receptor inhibitory peptide containing penacillamine (PCN) arginine-glycine-aspartic acid (PCN-RGD) and an antibody specific for the alpha(v)beta(3)-integrin specifically blocked both adhesion and migration. Adhesion of VSMC to Del1 was associated with organization of actin filaments and formation of focal contacts enriched in vinculin and alpha(v)beta(3). Furthermore, Del1 supported VSMC proliferation at least in part by inhibiting these cells from undergoing apoptosis. These data, in conjunction with evidence that Del1 expression is reactivated in vascular injury, suggest that Del1 may have a paracrine role in vessel wall development and remodeling.