Respiratory Failure following Abdominal Wall Reconstruction: An Analysis of the Nationwide Inpatient Sample.

BACKGROUND: Patients undergoing abdominal wall reconstruction are at increased risk of postoperative respiratory failure. Understanding the epidemiology of this complication may guide preventive efforts. METHODS: The authors performed a population-based retrospective cohort study of adults undergoing elective abdominal wall reconstruction (ventral hernia repair with component separation) in the United States from 2004 through 2011 using the Nationwide Inpatient Sample. RESULTS: Of 2283 patients undergoing elective abdominal wall reconstruction, 57 percent were women, with a median age of 57 years, median hospital stay of 5 days, and mean total cost of $23,730. Postoperative respiratory failure occurred in 212 patients (9.3 percent), 164 patients (7.2 percent) were discharged to a skilled nursing facility, and 18 patients (0.8 percent) died. On multivariate analysis, age, male sex, congestive heart failure, lung disease, obesity, and obstructive sleep apnea were independently associated with increased risk of respiratory failure. Respiratory failure was associated with significantly increased risk of death and discharge to a skilled nursing facility as well as significantly increased total cost and hospital length of stay. CONCLUSIONS: Respiratory failure is an uncommon but devastating complication of abdominal wall reconstruction. The authors report clinical risk factors that may facilitate perioperative risk-reduction strategies to improve outcomes of elective abdominal wall reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Comparison of Outcomes in Immediate Implant-Based Breast Reconstruction Versus Mastectomy Alone.

OBJECTIVES: Immediate implant-based techniques are common practice in post-mastectomy breast reconstruction. Previous studies have shown an increased complication rate in the setting of immediate versus delayed, MD reconstruction. We aimed to quantify any additional risk in complications when implant-based immediate breast reconstruction (IBR) is performed versus mastectomy alone. MATERIALS AND METHODS: We retrospectively reviewed all IBR cases and all mastectomies without reconstruction from 2007 to 2011. Patient characteristics, operative details, and complication rates were reviewed and analyzed. RESULTS: IBR was performed in 315 consecutive women; mastectomy alone was performed in 401 women. Patients undergoing mastectomy alone were more often older, diabetic, and more frequently underwent neoadjuvant chemotherapy or radiation. Overall complications were higher in the IBR group, most commonly reoperation and delayed wound healing. In a multivariate analysis, IBR, increasing age, body mass index, history of radiation therapy, smoking, and nipple-sparing mastectomy were independently associated with increased risk of complications. However, IBR was only independently associated with increased risk of major complications such as reoperation or readmission for intravenous antibiotics, not minor complications. CONCLUSION: Patients selected for IBR are inherently different than those undergoing mastectomy alone. After adjusting for these differences, the increased risk of complications seen in IBR is moderately increased over the risk of complications in mastectomy alone. The observed increased risk of major complications after IBR is largely due to the aggressive management of complications in the setting of a prosthetic implant. IBR is a safe reconstructive strategy with only a slightly increased risk over mastectomy alone.

OBJECTIFS: Les techniques de reconstruction mammaire immédiate par implant sont courantes après une mastectomie. Des études antérieures ont démontré un taux de complication plus élevé après une reconstruction immédiate qu'après une reconstruction tardive. Les auteurs ont cherché à quantifier le risque supplémentaire de complications après une reconstruction mammaire immédiate (RMI) par rapport à une mastectomie effectuée seule. MATÉRIEL ET MÉTHODOLOGIE: Les auteurs ont procédé à une analyse rétrospective de toutes les RMI et de toutes les mastectomies sans reconstruction effectuées entre 2007 et 2011. Ils ont étudié et analysé les caractéristiques de patientes, les détails des opérations et le taux de complications. RÉSULTATS: Selon l'analyse, 315 femmes consécutives ont subi une RMI et 401 femmes, une mastectomie seule. Les patientes qui avaient subi une mastectomie seule étaient souvent plus âgées, diabétiques et soumises à une chimiothérapie néoadjuvante ou à une radiothérapie. Les complications globales étaient plus élevées dans le groupe ayant subi une RMI, surtout à cause d'une réopération et d'une guérison plus lente des plaies. D'après une analyse multivariée, la RMI, le vieillissement, l'indice de masse corporelle, des antécédents de radiothérapiele tabagisme et une mastectomie épargnant le mamelon présentaient une corrélation indépendante avec un risque accru de complications. La RMI présentait seulement une corrélation indépendante avec un risque accru de complications majeures comme une réopération ou une réhospitalisation visant à administrer des antibiotiques par voie intraveineuse, et non de complications mineures. CONCLUSION: Les patientes sélectionnées pour la RMI sont foncièrement différentes de celles qui subissent une mastectomie seule. Après rajustement pour tenir compte de ces différences, le risque de complications observé après une RMI est légèrement plus élevé que celui qui s'associe à une mastectomie seule. Le risque accru de complications majeures observé après une RMI est largement attribuable à la prise en charge énergique des complications après un implant prothétique. La RMI est une stratégie de reconstruction sécuritaire dont le risque est seulement un peu plus élevé que la mastectomie seule.

Wound Morbidity in Minimally Invasive Anterior Component Separation Compared to Transversus Abdominis Release.

BACKGROUND: Transversus abdominis release is a novel approach for myofascial advancement in ventral hernia repair and has been hypothesized to have lower rates of wound complication than anterior component separation. METHODS: Patients who had a ventral hernia repair with either transversus abdominis release or minimally invasive anterior component separation from January of 2010 to January of 2016 were enrolled in this retrospective cohort study. Patient characteristics were collected through chart review. Primary outcomes were operative time and wound complications. Multiple linear/Poisson regression and Fisher's exact test were used to determine statistical significance. RESULTS: Of 142 patients analyzed, 75 subjects underwent Butler minimally invasive anterior component separation and 67 underwent transversus abdominis release. There were no differences in baseline characteristics between groups, except that the anterior component separation group had more immunosuppressed patients (35 percent versus 19 percent). Median operative time for anterior component separation was 6.3 hours versus 6.1 hours for transversus abdominis release (p = 0.6). Overall wound complications did not differ between the groups (p = 0.5). Compared with anterior component separation, transversus abdominis release had a similar incidence of seroma/hematoma (relative risk, 0.9; 95 percent CI, 0.5 to 1.7), wound infection (relative risk, 1.1; 95 percent CI, 0.5 to 2.2), and mesh infection (relative risk, 0.7; 95 percent CI, 0.2 to 3.4). Hernia recurrence was 12 percent for anterior component separation and 6 percent for transversus abdominis release (relative risk, 0.6; 95 percent CI, 0.2 to 1.7). Reoperation was required in 19 percent of anterior component separation and 12 percent of transversus abdominis release subjects (relative risk, 0.5; 95 percent CI, 0.2 to 1.2). CONCLUSIONS: Transversus abdominis release patients had similar operative times, wound complications, reoperations, and hernia recurrences compared with Butler minimally invasive anterior component separation patients. This contemporary comparison helps inform operative decisions for reconstructive surgeons. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Management of the Repeatedly Failed Cranioplasty Following Large Postdecompressive Craniectomy: Establishing the Efficacy of Staged Free Latissimus Dorsi Transfer/Tissue Expansion/Custom Polyetheretherketone Implant Reconstruction.

BACKGROUND: Postdecompressive craniotomy defect management following failed prior cranioplastyis challenging. The authors describe a staged technique utilizing free muscle transfer, tissue expansion, and custom polyetheretherketone (PEEK) implants for the management of previously failed cranioplasty sites in patients with complicating local factors. METHODS: Consecutive patients with previously failed cranioplasties following large decompressive craniectomies underwent reconstruction of skull and soft tissue defects with staged free latissimus muscle transfer, tissue expansion, and placement of custom computer-aided design and modeling PEEK implants with a 'temporalis-plus' modification to minimize temporal hollowing. Implants were placed in a vascularized pocket at the third stage by elevating a plane between the previously transferred latissimus superficial fascia (left on the skin) and muscle (left on the dura/bone). Patients were evaluated postoperatively for cranioplasty durability, aesthetic outcome, and complications. RESULTS: Six patients with an average of 1.6 previously failed cranioplasties underwent this staged technique. Average age was 33 years. Average defect size was 139 cm. Average time to procedure series completion was 14.9 months. There were no flap failures. One patient had early postoperative incisional dehiscence following PEEK implant placement that was managed by immediate scalp flap readvancement. At 21.9 month average follow-up, there were no cranioplasty failures. Three patients (50%) underwent 4 subsequent refining outpatient procedures. All patients achieved complete coverage of their craniectomy defect site with hear-bearing skin, acceptable head shape, and normalized head contour. CONCLUSIONS: The described technique resulted in aesthetic, durable craniectomy defect reconstruction with retention of native hear-bearing scalp skin in a challenging patient population.

Comparison of Synthetic and Biologic Mesh in Ventral Hernia Repair Using Components Separation Technique.

Ventral hernia repair (VHR) for large abdominal wall defects is challenging. Prior research established that the use of mesh is superior to suture closure alone and that component separation is an effective technique to combat loss of abdominal domain. Studies comparing component separation technique (CST) outcomes utilizing synthetic versus biologic mesh are limited. A retrospective review was conducted of 72 consecutive patients who underwent VHR with CST between 2006 and 2010 at our institution. Surgeon preference and the presence of contamination guided whether synthetic mesh (27 patients) or biologic mesh (45 patients) was used. Mean follow-up interval for all comers was 13.9 months and similar in both groups (P > 0.05). Degree of contamination and severity of premorbid medical conditions were significantly higher in the biologic mesh group, as reflected in the higher Ventral Hernia Working Group (VHWG) score (2.04 versus 2.86). Clinical outcomes, as measured by both minor and major complication rates and recurrence rates, were not significantly different. Minor complication rates were 26% in the synthetic group and 37% in the biologic group and major complication rates 15% in the synthetic group and 22% in the biologic group. There was 1 recurrence (4%) in the synthetic mesh group versus 5 (11%) in the biologic mesh group. Multivariable analysis for major complications revealed no significant difference for either synthetic or biologic mesh while controlling for other variables. Subset analysis of uncontaminated cases revealed recurrence rates of 4% in the synthetic mesh group and 6% in the biologic mesh group. VHR using CST and either synthetic mesh or biologic mesh resulted in low recurrence rates with similar overall complication profiles, despite the higher average VHWG grading score in the biologic mesh group. Our results support the VHWG recommendation for biologic mesh utilization in higher VHWG grade patients. In VHWG grade 2 patients, our clinical outcomes were similar, supporting the use of either type of mesh.

Robotic total pelvic exenteration with laparoscopic rectus flap: initial experience.

Total pelvic exenteration is a highly morbid procedure performed for locally advanced pelvic malignancies. We describe our experience with three patients who underwent robotic total pelvic exenteration with laparoscopic rectus flap and compare perioperative characteristics to our open experience. Demographic, tumor, operative, and perioperative factors were examined with descriptive statistics reported. Mean operative times were similar between the two groups. When compared to open total pelvic exenteration cases (n = 9), median estimated blood loss, ICU stay, and hospital stay were all decreased. These data show robotic pelvic exenteration with laparoscopic rectus flap is technically feasible. The surgery was well tolerated with low blood loss and comparable operative times to the open surgery. Further study is needed to confirm the oncologic efficacy and the suggested improvement in surgical morbidity.

Comparison of vertical and oblique rectus abdominis myocutaneous flaps for pelvic, perineal, and groin reconstruction.

BACKGROUND: Wound complications after perineal and groin obliterative procedures are a significant cause of morbidity, particularly following chemoradiation therapy. Vertical and, increasingly, oblique rectus abdominis myocutaneous flaps have been used to fill potential dead space and bring healthy, vascularized tissue into the defect. The authors compared the complications and outcomes of patients undergoing perineal or groin reconstruction with vertical or oblique rectus abdominis myocutaneous flaps. They hypothesized that the oblique flap offers outcomes similar to those of the vertical flap, without an increased risk of complications. METHODS: All patients who underwent immediate reconstruction of perineal, pelvic, or groin defects using vertical (n=49) or oblique rectus abdominis myocutaneous (n=22) flaps over the past 10 years at the University of Washington Medical Center were reviewed retrospectively. Patient, disease, and obliterative procedure characteristics and donor- and recipient-site complications were compared. Statistical analysis was performed using the t test for continuous variables and Fisher's exact test for categorical variables. RESULTS: There were no statistically significant differences in major or minor donor- or recipient-site complication rates, need for augmented fascial closure, need for additional flaps, flap loss, readmission, or reoperation rate between the two groups. CONCLUSIONS: Immediate reconstruction of perineal or groin defects with oblique rectus abdominis myocutaneous flaps results in complication rates similar to those with reconstruction using with vertical flaps. Oblique flap reconstruction is a reasonable and safe alternative, providing several distinct advantages over the vertical flap, including greater arc of rotation, thinner skin paddle, less bulk, and limited fascial harvest. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Implantable Cook-Swartz Doppler probe versus Synovis Flow Coupler for the post-operative monitoring of free flap breast reconstruction.

BACKGROUND: The Cook-Swartz Doppler has long been a trusted tool for close monitoring of blood flow after microvascular reconstruction; however, device implantation requires additional operating time. Synovis Life Technologies, Inc. received FDA approval in 2010 for the Flow Coupler, which combines an end-to-end anastomotic coupler with a removable 20 MHz Doppler, allowing both procedures to be performed simultaneously. However, its short history of widespread use necessitates further evaluation in the clinical setting. The authors studied the Synovis Flow Coupler in comparison to the more well-established Cook-Swartz Doppler for effectiveness and reliability in detection of vascular compromise. METHODS: The authors reviewed 220 free flap breast reconstructions in 150 patients over a three-year period in which either the Cook-Swartz Doppler or the Synovis Flow Coupler was implanted to monitor blood flow. Outcomes measured include false-positive or false-negative rates (FPR, FNR); rates of OR take-back and salvage; and flap survival. RESULTS: FPR was 1.0% for the Cook-Swartz Doppler and 1.9% for the Synovis Flow Coupler (p>0.05). FNR was 0.0% for both groups. Take-back rates were 10.1% for the Cook-Swartz, and 4.5% for Synovis (p>0.05). Flap failure rates were 1.8% and 0.9% for the Cook-Swartz and Synovis devices, respectively (p>0.05). CONCLUSIONS: Our study reveals no statistically significant differences in outcomes for free flap breast reconstruction where either the Cook-Swartz Doppler or the Synovis Flow Coupler was used to monitor blood flow to the perforator flap. LEVEL OF EVIDENCE: III.

Comparison of outcomes using AlloDerm versus FlexHD for implant-based breast reconstruction.

BACKGROUND: Prosthetic reconstruction using human acellular dermis (ADM) is a common practice in breast reconstruction. AlloDerm and FlexHD are two different forms of ADM, each with unique characteristics. No studies have directly compared the postoperative complications of these 2 products. METHODS: The outcomes of 547 consecutive implant-based breast reconstructions were reviewed. RESULTS: Reconstruction was performed in 382 consecutive women (547 total breasts), employing mostly immediate reconstruction (81%). Mean follow-up was 6.4 months. Among immediate reconstructions, 165 used AlloDerm and 97 used FlexHD. Complications were similar by univariate analysis. In multivariate analysis, smoking and higher initial implant fill were risk factors for delayed healing. The use of FlexHD, single-stage reconstruction, and smoking were independent risk factors for implant loss. CONCLUSIONS: There is no significant difference in the complication rates between AlloDerm and FlexHD in immediate breast reconstruction. Multivariate analysis suggests that FlexHD may be a risk factor for implant loss.

Clinical utility of CT angiography in DIEP breast reconstruction.

BACKGROUND: CT angiography has become the gold-standard imaging modality prior to DIEP flap breast reconstructions. Recent studies show excellent correlation between CTA and operative perforator location, but not their clinical significance. This study seeks to specifically evaluate the clinical utility of CTA in DIEP free flaps. METHODS: Preoperative CT angiography of the deep inferior epigastric system was obtained in 52 sequential DIEP free flaps involving 37 patients with dominant perforators marked by radiologist. Planned and used perforators were documented by the surgeon before and after the operation. RESULTS: A total of 62 out of 76 planned perforators were ultimately used (82%). Of those not used, 71% were abandoned due to inadequacy of preoperative CT. An additional 38 perforators were used that were not part of the initial preoperative plan, 60% of which were added due to inadequacy of the preoperative CT for planning. In total 23/52 flaps (44%) involved intraoperative changes due to features not appreciated on preoperative CT. CONCLUSION: CTA mapping of perforators prior to DIEP flap surgery increases surgeon confidence and reduces operative time; however, there are still a significant number of changes made based on clinical judgment. This study highlights the importance of surgeon review of CTA images. Caution is warranted in reliance on CTA mapping, and significant perforators should not be sacrificed until the anticipated perforator(s) have been exposed and evaluated. LEVEL OF EVIDENCE: Level 3.

Duration of antibiotics after microsurgical breast reconstruction does not change surgical infection rate.

BACKGROUND: Infection rates for breast surgery are 3 to 15 percent, higher than average for a clean surgical procedure. Preoperative and postoperative antibiotics have lowered infection rates in other surgical groups, yet there is no consensus on postoperative prophylactic antibiotic use in microsurgical breast reconstruction. METHODS: A retrospective review of consecutive patients who underwent autologous breast reconstruction between 2006 and 2009 was performed. Specific risk factors for autologous reconstruction were reviewed, including medical comorbidities, irradiation, and chemotherapy history. Data were collected on type and duration of prophylactic antibiotics. A prospective cohort of patients who received only 24 hours of postoperative antibiotics was identified. The incidence of surgical-site infections was measured using Centers for Disease Control and Prevention criteria. RESULTS: A total of 256 patients with 360 microvascular breast reconstructions who received both preoperative and postoperative prophylactic antibiotics were analyzed. The overall surgical-site infection rate was 17.2 percent (44 of 256 patients). Surgical-site infection was correlated with increased age, tobacco use, and prior radiation. Duration of postoperative antibiotic use did not differ in those patients who developed surgical-site infections (6.2 versus 7.7 days; p = 0.19). Eighty-two patients (32 percent) received only 24 hours of postoperative antibiotics, while 174 (68 percent) received more than 24 hours of antibiotics for a median duration of 10 days. There was no difference in the overall surgical-site infection rate in those who received more than 24 hours of antibiotics (19.5 versus 15.5 percent; p = 0.47). CONCLUSION: There was no reduction in the overall surgical-site infection rate among autologous breast reconstruction patients who received postoperative antibiotic prophylaxis for more than 24 hours. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Reconstruction of total laryngopharyngectomy defects with deep inferior epigastric perforator flaps.

Laryngopharyngectomy reconstruction with microvascular free flaps remains challenging. Current methods of reconstruction include anterolateral thigh, radial forearm, and jejunal flaps, all of which have substantial donor site morbidity. We present a novel approach for total laryngopharyngectomy reconstruction using deep inferior epigastric perforator (DIEP) flaps. A retrospective review of head and neck reconstruction cases performed at Harbor-UCLA from 2006 to 2007 was performed. Those undergoing DIEP flaps were identified; management and postoperative course were analyzed. Two patients underwent successful reconstruction of total laryngopharyngectomy defects using DIEP flaps. Flaps up to 10 x 30 cm were harvested. Average donor vessel diameters were 2.5 cm and 3.0 cm for the artery and vein, respectively. The abdominal wounds were closed primarily. Flap survival was 100% with no emergent reexplorations. There were no postoperative bulges or hernias, and no leaks were detected on postoperative swallow evaluation. The DIEP flap is a useful addition to the armamentarium for reconstruction of total laryngopharyngectomy defects. Pedicle length is abundant, and donor vessel caliber is excellent. Large surface-area flaps can be harvested; excess flap can be deepithelialized or utilized for external skin. Primary closure of the donor site can be routinely achieved, negating the need for skin grafts.

Intraoperative Sensorcaine significantly improves postoperative pain management in outpatient reduction mammaplasty.

BACKGROUND: Breast reduction is one of the most frequently performed plastic surgical procedures in the United States; more than 160,500 patients underwent the procedure in 2005. Many outpatient reduction mammaplasty patients report the greatest postoperative discomfort in the first 48 hours. The authors' investigated the effect of intraoperative topical application of the long-acting local anesthetic agent bupivacaine (Sensorcaine or Marcaine) on postoperative pain, time to postanesthesia care unit discharge, and postoperative use of narcotic medication. METHODS: In a prospective, randomized, single-blind trial, intraoperative use of Sensorcaine versus placebo (normal saline) was compared. Postoperative pain was quantified using the visual analogue scale, and time to discharge from the postanesthesia care unit was recorded. Patients documented their outpatient pain medication usage. RESULTS: Of the 37 patients enrolled in the study, 20 were treated with intraoperative topical Sensorcaine and 17 received placebo. Patients treated with Sensorcaine were discharged home significantly faster (2.9 hours versus 3.8 hours, p = 0.002). The control arm consistently had higher pain scores in the postanesthesia care unit (although not statistically significant) than the Sensorcaine group using the visual analogue scale system. Furthermore, patients receiving Sensorcaine required significantly less narcotic medication while recovering at home (mean, 3.5 tablets of Vicodin) than the control group (mean, 6.4 tablets; p = 0.001). There were no complications resulting from Sensorcaine usage. CONCLUSIONS: This prospective, randomized, single-blind study demonstrates that a single dose of intraoperative Sensorcaine provides a safe, inexpensive, and efficacious way to significantly shorten the length of postanesthesia care unit stay and significantly decrease postoperative opioid analgesic use in patients undergoing ambulatory reduction mammaplasty.

Type I collagen synergistically enhances PDGF-induced smooth muscle cell proliferation through pp60src-dependent crosstalk between the alpha2beta1 integrin and PDGFbeta receptor.

Smooth muscle cells (SMCs) are exposed to both platelet-derived growth factor (PDGF) and type I collagen (CNI) at the time of arterial injury. In these studies we explore the individual and combined effects of these agonists on human saphenous vein SMC proliferation. PDGF-BB produced a 5.5-fold increase in SMC DNA synthesis whereas CNI stimulated DNA synthesis to a much lesser extent (1.6-fold increase). Alternatively, we observed an 8.3-fold increase in DNA synthesis when SMCs were co-incubated with CNI and PDGF-BB. Furthermore, stimulation of SMCs with PDGF-BB produced a significant increase in ERK-2 activity whereas CNI alone had no effect. Co-incubation of SMCs with PDGF-BB and CNI resulted in ERK-2 activity that was markedly greater than that produced by PDGF-BB alone. In a similar fashion, PDGF-BB induced phosphorylation of the PDGF receptor beta (PDGFRbeta) and CNI did not, whereas concurrent agonist stimulation produced a synergistic increase in receptor activity. Blocking antibodies to the alpha2 and beta1 subunits eliminated this synergistic interaction, implicating the alpha2beta1 integrin as the mediator of this effect. Immunoprecipitation of the alpha2beta1 integrin in unstimulated SMCs followed by immunoblotting for the PDGFRbeta as well as Src family members, pp60(src), Fyn, Lyn, and Yes demonstrated coassociation of alpha2beta1 and the PDGFRbeta as well as pp60(src). Incubation of cells with CNI and/or PDGF-BB did not change the degree of association. Finally, inhibition of Src activity with SU6656 eliminated the synergistic effect of CNI on PDGF-induced PDGFRbeta phosphorylation suggesting an important role for pp60(src) in the observed receptor crosstalk. Together, these data demonstrate that CNI synergistically enhances PDGF-induced SMC proliferation through Src-dependent crosstalk between the alpha2beta1 integrin and the PDGFRbeta.

The role of phospholipase C and phosphatidylinositol 3-kinase in vascular smooth muscle cell migration and proliferation.

BACKGROUND: Vascular smooth muscle cell (SMC) proliferation and migration both contribute to the formation of intimal hyperplasia. Phospholipase C (PLC) and phosphatidylinositol 3-kinase (PI3-K) are ubiquitous signaling proteins that mediate multiple cellular events. In this study, we investigate the role of PLC and PI3-K in platelet-derived growth factor (PDGF) and extracellular matrix protein (ECM) induced SMC proliferation and migration. MATERIAL AND METHODS: Proliferation of human saphenous vein SMC was assessed by (3)H-thymidine incorporation. SMC migration was evaluated using a microchemotaxis chamber. U-73122 was used as a general inhibitor for PLC, and D609 and ET-18-OCH3, respectively, were used to block the isotypes of PLC, phosphatidylcholine- (PC-), and phosphatidylinositol- (PI-) specific PLC. PI3-K activity was inhibited using two selective inhibitors, LY-294002 and wortmannin. RESULTS: PDGF and Type 1 collagen (CN-I) stimulated SMC proliferation, whereas PDGF and four distinct extracellular matrix proteins CN-I, Type 4 collagen (CN-IV), fibronectin (FN), and laminin (LN) stimulated SMC migration. Both isotypes of PLC as well as PI3-K were necessary for PDGF- and CN-I-induced proliferation. Signaling for migration, however, was more specific. Of the various signaling proteins studied, only PI-PLC was necessary for PDGF-induced SMC migration. Conversely, PI3-K was the only signaling protein necessary for SMC migration in response to ECM proteins. CONCLUSION: The signaling pathways necessary for PDGF- and CN-I-induced SMC proliferation involve both isotypes of PLC as well as PI3-K. The signaling pathways used by growth factors and ECM to stimulate SMC migration are more selective. Understanding the intracellular signaling pathways required for SMC proliferation and migration may allow the development of tools to selectively block intimal hyperplasia.

TGF-beta stimulates collagen (I) in vascular smooth muscle cells via a short element in the proximal collagen promoter.

BACKGROUND: Accumulation of extracellular matrix contributes to the development of intimal hyperplasia. Transforming growth factor beta (TGF-beta) stimulates the production of several matrix proteins in vascular smooth muscle cells (SMC) including type I collagen, but the underlying mechanisms of TGF-beta's effects are not well understood. MATERIALS AND METHODS: The effect of TGF-beta on type I collagen biosynthesis was determined by a [3H]proline incorporation assay and Northern blotting. The promoter of human alpha2(I) procollagen (COL1A2) gene was analyzed by transient transfection analysis and gel mobility shift assay. RESULTS: Treatment of human vascular SMC with TGF-beta stimulated collagen synthesis and increased the level of alpha2(I) collagen mRNA. A collagen-luciferase reporter gene, constructed by linking the human COL1A2 promoter with the firefly luciferase gene, was transiently expressed in human SMC. Treatment with TGF-beta significantly stimulated the activity of this collagen-luciferase reporter. Using deletion analysis, we identified a 150 bp DNA fragment (-334 to -184) in the human COL1A2 promoter as the site through which TGF-beta mediates collagen gene expression in human SMC. Gel mobility shift assays demonstrated that this 150 bp DNA fragment formed conjugates with multiple nuclear factors derived from SMC, a process that was further enhanced by TGF-beta. CONCLUSIONS: TGF-beta stimulates the human type I collagen gene via a DNA element located in the proximal region of its promoter. Interventions that disrupt interaction between this DNA element and nuclear factors may block the production of collagen in response to TGF-beta and consequently may have a significant effect on the development of intimal hyperplasia.

The signaling protein Rho is necessary for vascular smooth muscle migration and survival but not for proliferation.

BACKGROUND: The small GTPase Rho has been implicated in a variety of cellular processes. Vascular smooth muscle cell (SMC) migration, proliferation, and apoptosis are important events that contribute to the formation of intimal hyperplasia. To better understand the importance of Rho in intimal hyperplasia, we evaluated the necessity of Rho for these 3 cellular processes. METHODS: We used for these studies a recombinant C3 exoenzyme (C3), which selectively adenosine diphosphate-ribosylates and, thus, functionally inactivates Rho. SMC migration was determined by scratch and modified Boyden chamber assays, proliferation by tritiated-thymidine incorporation, and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling. RESULTS: Pretreatment of human SMC with C3 overnight resulted in adenosine diphosphate-ribosylation and inactivation of Rho. Inactivation of Rho completely eliminated SMC migration in response to platelet-derived growth factor (PDGF)-AB. Furthermore, C3 blocked phosphorylation of focal adhesion kinase, tensin, and paxillin, which are essential for cellular migration. In contrast, C3 did not significantly affect DNA synthesis in response to PDGF-AB or activation of mitogen-activated protein kinase, a signaling mediator of PDGF-stimulated proliferation. However, prolonged inactivation of Rho by C3 induced apoptosis of SMC. CONCLUSIONS: The small GTPase Rho is necessary for vascular SMC migration and cell survival but not for proliferation. Manipulation of Rho might have therapeutic value in modulating intimal hyperplasia.

Prognostic factors in pancreatic endocrine neoplasms: an analysis of 136 cases with a proposal for low-grade and intermediate-grade groups.

PURPOSE: In some organs (eg, the lung), endocrine tumors are classified on the basis of mitotic rate and necrosis. The purpose of this study was to evaluate prognostic factors in pancreatic endocrine neoplasms recently treated at a single institution. PATIENTS AND METHODS: In 136 patients undergoing surgery from 1979 to 1998, the influence on disease-free survival (DFS) and disease-specific survival (DSS) of tumor size, mitotic rate, vascular invasion, necrosis, metastases, and nuclear grade was determined. Cases were further grouped according to an existing proposed classification system and then regrouped on the basis of mitotic rate (< 2 mitoses per 50 high-power fields v higher) and necrosis (present or absent) into low- and intermediate-grade groups. RESULTS: Correlations with DFS and DSS in univariate analysis included < or = 2 mitoses per 50 high-power fields (P =.001, P =.002), vascular invasion (P =.02, P =.04), size < or = 2 cm (P =.01, P =.05), metastases (P =.0002, P =.07), necrosis (P =.002, P =.16), and nuclear grade (P =.04, P =.33), respectively. By multivariate analysis, for DFS, tumor necrosis and presence of metastases retained significance (P =.01, P =.04, respectively). For DSS, only mitotic rate was a prognostic factor (P =.02). Among the 18 macroadenomas, eight borderline tumors, and 48 low-grade carcinomas, there was no significant difference in DSS between any groups (P =.3). However, in evaluating our newly proposed groups, the differences in DFS and DSS between low- and intermediate-grade groups were highly significant (P =.0007, P =.006, respectively). CONCLUSION: Pancreatic endocrine neoplasms exhibit a spectrum of biologic behavior, and the proposed benign (macroadenoma) and borderline groups contain potentially aggressive tumors. An alternative system based on mitotic rate and necrosis correlates strongly with survival without specifically designating any group as benign.