Patient Outcomes After Stent Failure for the Treatment of Acute Esophageal Perforation.

BACKGROUND: Esophageal stent placement for acute esophageal perforation has become part of the treatment algorithm for many thoracic surgery programs. Despite high success rates, there are patients for which stent placement is not successful. This investigation summarizes the outcomes of a relatively large group of such patients. METHODS: Patients who underwent esophageal stent placement for an acute perforation but required conversion to another form of therapy were identified from a prospectively collected institutional database. Excluded were patients whose perforation was associated with a malignancy. Patient demographics, operative and nonoperative invasive procedures, morbidities, mortality, and 6-month follow-up after discharge were reviewed. RESULTS: Between 2008 and 2015, 26 patients who failed to seal their esophageal leak after stent placement were identified. Eighteen (69%) of these patients required an operative repair with primary closure of the perforation. Four (15%) primary repairs had a persistent leak controlled with subsequent stent placement. Four (15%) patients required an esophagectomy with cervical esophagostomy. Three patients (11%), because of comorbid conditions, were referred for hospice care. One patient (3%) refused operative repair and developed a chronic fistula that resolved with subsequent stent placement. CONCLUSIONS: Esophageal stent placement continues to be a safe and effective treatment for acute esophageal perforation. Patients whose perforation does not seal with initial stent placement can be treated with primary surgical repair or esophagectomy without increasing their morbidity or mortality or compromising their prognosis.

An Assessment of the Frequency of Palliative Procedures in Thoracic Surgery.

OBJECTIVES: Palliative care is a medical specialty focused on improving the quality of life of patients and their families with life threatening illness by preventing or relieving suffering. An assessment of a thoracic surgery service was performed to identify the scope and frequency of care that was considered palliative and any implications the findings might have on the current thoracic surgery residency curriculum. METHODS: A retrospective review of a prospectively collected database of general thoracic surgery procedures performed over a 5-year period at a single institution was performed. Procedures considered palliative were reviewed for demographics, diagnoses, palliative prognosis score, treatment, morbidity, operative mortality, and survival. Excluded were referrals from thoracic surgery to other specialties for palliative procedures. RESULTS: During the study period, 3842 procedures were performed of which 884 (23%) were palliative. Indications included pleural or pericardial effusion or both, dysphagia, hemoptysis, tracheobronchial obstruction, bronchopleural fistula, and tracheoesophageal fistula. The majority was related to a malignancy. Only 127 patients (14%) had a palliative care assessment before thoracic surgery consultation. Mean survival following thoracic surgery intervention was 110 days for patients with malignancy. CONCLUSIONS: This investigation found that thoracic surgeons commonly care for patients when the intention or indication or both is palliation. Most of these patients have an associated malignancy, a poor performance status and a projected significantly decreased survival compared with the general population. Thoracic surgeons should be familiar with the concepts of palliative care and consideration should be given to expanding exposure to the principles of palliative care in the cardiothoracic residency training curriculum.

The Effects of a Multidisciplinary Care Conference on the Quality and Cost of Care for Lung Cancer Patients.

BACKGROUND: A prospective, multidisciplinary care conference (MDC) has been shown to result in measurable benefits for patients with non-small cell lung cancer (NSCLC). However whether a MDC also results in a difference in resource utilization and cost as well as whether these benefits persist across a multiinstitutional system has not been reported. This investigation compared propensity-matched patients with NSCLC whose care was coordinated through a MDC to patients without access to an MDC across a geographically diverse system of hospitals. METHODS: The Premiere database (Premier Inc, Charlotte, NC) for a health system's 70 hospitals was used to identify patients undergoing treatment for NSCLC during a 5-year period. Propensity matching was used to populate an MDC and non-MDC cohort. The two cohorts were compared for the costs of staging and diagnosis as well as the timeliness and quality of care metrics. RESULTS: Between 2008 and 2013, 13,254 patients were propensity matched. Patient demographics and Charlson comorbidity scores were comparable after matching. Significant differences were identified in adherence to national guidelines (p < 0.0001) for staging and treatment (p < 0.0001), timeliness of care (p < 0.0001), and costs (p < 0.0001) between the two groups. CONCLUSIONS: This investigation found that patients with NSCLC realize improved quality and timeliness of care when that care is coordinated through an MDC. The use of an MDC was also associated with a significant reduction in cost. These differences persisted across a geographically diverse set of hospitals, providers, and patients. Prospective MDCs should be considered integral and compulsory for patients with NSCLC.

An Assessment of the Optimal Time for Removal of Esophageal Stents Used in the Treatment of an Esophageal Anastomotic Leak or Perforation.

BACKGROUND: Esophageal stent for the treatment of a perforation or anastomotic leak has been shown to be effective and safe. However, the optimal timing for stent removal is in question. This purpose of this investigation was to identify a time for stent removal in patients treated for an acute perforation or anastomotic leak that resulted in sealing of the leak while minimizing the incidence of stent-related complications. METHODS: Patients undergoing esophageal stent placement for the treatment of an acute perforation or intrathoracic anastomotic leak were identified from a single institution's prospectively collected database. Patient outcomes were recorded and analyzed. Complications were segregated by stent dwell time. RESULTS: During the study period, 162 patients underwent esophageal stent placement for an acute perforation (n = 117) or anastomotic leak (n = 45). Patients whose stent was removed in less than 28 days after placement for an acute perforation realized a stent complication rate that was independently reduced by 39% (odds ratio, 0.61; 95% confidence interval, 0.54 to 0.78; p < 0.01), whereas patients whose stent was removed in less than 14 days after placement for an acute perforation realized a stent complication rate that was independently reduced by 56% (odds ratio, 0.44; 95% confidence interval, 0.38 to 0.69; p < 0.001). CONCLUSIONS: Endoluminal esophageal stent placement is a safe and effective treatment for patients with an acute esophageal perforation or intrathoracic anastomotic leak after esophagectomy. Removal of stents at 2 weeks for anastomotic leak or 4 weeks for perforation has the potential to significantly decrease the incidence of complications associated with stent use.

A propensity-matched comparison of cost and outcomes after esophageal stent placement or primary surgical repair for iatrogenic esophageal perforation.

OBJECTIVES: Esophageal stent placement has been shown to be a safe and effective treatment for acute esophageal perforation in selected patients. However, a comparison between surgical repair and stent placement has not been reported. This investigation compares the outcomes and costs of the 2 treatment modalities. METHODS: The Premiere database for a single health system's hospitals was used to identify patients undergoing treatment for an acute intrathoracic esophageal perforation over a 4-year period. Patient cohorts for stent placement or surgical repair were formed using propensity matching. The 2 cohorts were compared for length of stay, morbidity, mortality, and costs. RESULTS: Between 2009 and 2012, 60 patients undergoing esophageal stent placement or surgical repair were propensity matched. Mean patient age and Charlson comorbidity scores did not differ significantly (P = .4 and P = .4, respectively). Significant differences in morbidity (4% vs 43%; P = .02), mean length of stay (6 vs 11 days; P = .0007), time to oral intake (3 vs 8 days; P = .0004), and cost ($91,000 vs $142,000; P < .0001) were identified in the esophageal stent cohort when compared with patients receiving surgical repair. Operative mortality did not differ significantly. CONCLUSIONS: Esophageal stent placement for the treatment of an acute esophageal perforation seems to be as effective as surgical repair when compared between propensity-matched patients. However, stent placement resulted in a shorter length of stay, lower rates of morbidity, and lower costs when compared with traditional surgical repair.

A propensity-matched comparison of pleurodesis or tunneled pleural catheter for heart failure patients with recurrent pleural effusion.

BACKGROUND: Patients with severe heart failure often have recurrent pleural effusions that produce dyspnea and shortness of breath. It is unclear whether chemical pleurodesis or the placement of a tunneled pleural catheter that can be used for intermittent pleural drainage produces superior palliation, a shorter hospital stay, and less morbidity. This investigation compares these two treatments. METHODS: Patients with a recurrent, symptomatic, pleural effusion secondary to advanced heart failure who had undergone at least two unilateral thoracenteses were identified. Two patient groups were formed by propensity matching patients who received either talc pleurodesis or a tunneled pleural catheter. Patient demographics, length of stay, need for further intervention for the pleural effusion, and procedural morbidity and mortality were collected and compared. Patients who had undergone ventricular assist device placement or cardiac transplant were excluded. RESULTS: Over a 5-year period, 80 patients undergoing treatment were identified and propensity matched. All 80 patients were classified as having class III or IV heart failure. No significant differences in palliation from their effusion were identified. However, the group treated with a tunneled pleural catheter realized a significantly shorter hospital stay as well as a lower rate of operative morbidity and readmissions than patients undergoing talc pleurodesis. CONCLUSIONS: This investigation found that a tunneled pleural catheter provided palliation of patients' pleural effusions and freedom from reintervention equal to that of talc pleurodesis using thoracoscopy while resulting in a shorter mean length of hospital stay. Lower rates of operative morbidity and readmission related to the pleural effusion were also seen in the tunneled catheter treatment group. This method of palliation of recurrent pleural effusion should be considered for symptomatic patients with advanced heart failure.

An analysis of esophageal stent placement for persistent leak after the operative repair of intrathoracic esophageal perforations.

BACKGROUND: Surgical repair of esophageal perforation has been the mainstay of therapy for patients without associated esophageal malignancy or diffuse mediastinal necrosis. However, the leak rate after primary surgical repair is reported to range between 15% and 20% and increases to 45% and 70% in patients whose repair is delayed beyond 24 hours. This analysis reviews patients who experienced a leak after the operative repair of an esophageal perforation treated with esophageal stent placement. METHODS: Patients undergoing esophageal stent placement for the treatment of a leak after the operative repair of an intrathoracic esophageal perforation were identified from a single institution's database, which included patients initially treated at other facilities. Patient outcomes were recorded and analyzed. RESULTS: During a 7-year period, 32 esophageal stents were placed in 29 patients who experienced an esophageal leak after operative repair. Associated surgical procedures were simultaneously performed in 7 (24%) patients. Leak occlusion occurred in 27 patients (93%). Two patients required a reoperative repair. Twenty-five patients (86%) were able to initiate oral nutrition within 72 hours of stent placement. Stent migration in 5 patients (19%) required repositioning (n=2) or replacement (n=3). Stents were removed at a mean of 22±16 days after placement. Mean hospital length of stay was 8±11 days. CONCLUSIONS: Endoluminal esophageal stent placement is a safe and effective treatment for the majority of leaks after the operative repair of an intrathoracic esophageal perforation. Stent placement resulted in rapid leak occlusion and provided the opportunity for early oral nutrition while eliminating the need for reoperative repair or esophageal exclusion in the majority of patients.

A comparison of length of stay, readmission rate, and facility reimbursement after lobectomy of the lung.

BACKGROUND: Readmission to the hospital has become a focus for payers with the threat of nonpayment for preventable readmissions and a global penalty for excessive readmissions rates. This study compares readmission rates with lengths of stay (LOS) for patients undergoing lobectomy of the lung and the potential impact on reimbursement. METHODS: The Premier database for a single health system's hospitals was used to identify patients undergoing lobectomy for non-small cell lung cancer by cardiothoracic surgeons over a 5-year period. Charlson comorbidity scores were also calculated. Regression analysis was used to study the relationship between length of stay and readmission rates. A comparison of the effects of LOS and readmission on reimbursement was also performed. RESULTS: During the study period, 4,296 lobectomies were performed in 61 hospitals within the healthcare system that met the study's inclusion criteria. A readmission was recorded for 289 patients (7%). Factors associated with readmission were length of stay less than 5 days or more than 16 days and age more than 78 years (p = 0.001). An analysis of the effects of LOS and readmission on reimbursement found an extension of LOS was more cost effective than a readmission. CONCLUSIONS: This review found that mean LOS after lobectomy is negatively associated with readmission rates, with the maximal effect being before postoperative day 5. Furthermore, facility reimbursement was optimized when LOS was extended to minimize the risk of readmission.

A propensity-matched comparison of pleurodesis or tunneled pleural catheter in patients undergoing diagnostic thoracoscopy for malignancy.

BACKGROUND: Patients with a suspected malignant pleural effusion occasionally require thoracoscopy to achieve a diagnosis. It is unclear whether chemical pleurodesis or the placement of a tunneled pleural catheter (TPC) that can be used for intermittent pleural drainage produces superior palliation, a shorter hospital stay, and less morbidity. This investigation compares these 2 treatment groups. METHODS: Patients with a recurrent, symptomatic, pleural effusion suspected of having a malignant etiology who underwent a thoracoscopic exploration after at least 2 nondiagnostic thoracenteses were identified. Two patient groups were formed, comprised of patients who received either talc pleurodesis or a TPC at the conclusion of the procedure, using propensity matching. Patient demographics, length of stay, interval until the initiation of systemic therapy, need for further intervention for the pleural effusion, and procedural morbidity and mortality were collected and compared. RESULTS: Over a 6-year period, 60 patients undergoing treatment were identified and propensity matched. No significant differences in mean age or palliation from their effusion were identified. However, the group treated with TPC realized a significantly shorter hospital stay and interval to systemic therapy for their malignancy as well as a lower rate of operative morbidity than patients undergoing talc pleurodesis. CONCLUSIONS: This investigation found that a TPC provided palliation of patients' malignant pleural effusions and freedom from reintervention equal to that of talc pleurodesis after thoracoscopy while resulting in a shorter mean length of hospital stay and interval to the initiation of systemic therapy. Lower rates of operative morbidity were also seen in the TPC treatment group. This method of palliation of a malignant pleural effusion should be considered when diagnostic thoracoscopy reveals a malignant pleural effusion.

A comparison of quality and cost indicators by surgical specialty for lobectomy of the lung.

OBJECTIVES: This investigation compared patients undergoing lobectomy for non-small cell lung cancer by either a general surgeon or a cardiothoracic surgeon across a geographically diverse system of hospitals to see whether a significant difference in quality or cost was present. METHODS: The Premiere administrative database and tumor registry data of a single health system's hospitals was used to compare adherence to national treatment guidelines, patient outcomes, and charges for patients undergoing lobectomy for non-small cell lung cancer in a 5-year period. Surgeons performing lobectomy were designated as a general surgeon or cardiothoracic surgeon according to their national provider number and board certification status. Excluded from analysis were centers that performed fewer than 50 lobectomies during the study period. RESULTS: During the study period, 2823 lobectomies were performed by 46 general surgeons and 3653 lobectomies were performed by 29 cardiothoracic surgeons in 54 hospitals in a single health care system. Significant differences were found between general and cardiothoracic surgeons with respect to adherence to national guidelines in staging and treatment, mean length of stay, significant morbidity, and operative mortality. Mean charges for lobectomy of the lung were also found to differ significantly between general and cardiothoracic surgeons. CONCLUSIONS: This review found that currently measurable indicators for quality of care were significantly superior and overall charges were significantly reduced when a lobectomy for non-small cell lung cancer was performed by a cardiothoracic surgeon rather than by a general surgeon.

Palliative therapy for patients with unresectable esophageal carcinoma.

Most patients diagnosed with carcinoma of the esophagus do not undergo therapy with curative intent. The focus of treatment for these patients is to maximize their progression-free survival and palliate the most common sequelae of their disease: dysphagia, malnutrition, pain, and intraluminal tumor bleeding. This article discusses the available treatment options for palliation of patients with unresectable esophageal cancer.

Analysis of unsuccessful esophageal stent placements for esophageal perforation, fistula, or anastomotic leak.

BACKGROUND: Esophageal stent placement for the treatment of a perforation, anastomotic leak, or fistula has been adopted by some thoracic surgeons. Results have been reported for this technique, but little discussion has focused on treatment failures. This analysis reviews patients in whom esophageal stent placement was not successful in an attempt to identify factors that may increase the likelihood of failure of this technique. METHODS: Patients undergoing esophageal stent placement for the treatment of an esophageal perforation, anastomotic leak, or fistula in which the stent failed to adequately seal the esophageal leak were identified from a single institution's database. The anatomic location, chronicity, and cause of the esophageal leak were recorded using a newly developed classification system. Comparison was made to patients in whom stent placement was successful. RESULTS: Over a 7-year period, 187 patients had an esophageal stent placed for esophageal leaks. Fifteen (8%) of these patients required traditional operative repair when the esophageal stent failed to resolve the esophageal leak after an average of 3 days. A comparison of the 2 patient groups found that stent failure was significantly more frequent in patients who had an esophageal leak of the proximal cervical esophagus, 1 that traversed the gastroesophageal junction, an esophageal injury longer than 6 cm, or an anastomotic leak associated with a more distal conduit leak (p<0.05). Malignancy or previous radiation therapy was not associated with treatment failure. CONCLUSIONS: This investigation identified 4 factors that significantly reduce the effectiveness of esophageal stent placement for the treatment of esophageal perforation, fistula, or anastomotic leak. These potential contraindications should be considered when developing a treatment plan for individual patients and may prompt traditional operative repair as initial therapy.

Interferon Regulatory Factor 1 (IRF-1) induces p21(WAF1/CIP1) dependent cell cycle arrest and p21(WAF1/CIP1) independent modulation of survivin in cancer cells.

We have shown that the ectopic expression of Interferon Regulatory Factor 1 (IRF-1) results in human cancer cell death accompanied by the down-regulation of the Inhibitor of Apoptosis Protein (IAP) survivin and the induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1). In this report, we investigated the direct role of p21 in the suppression of survivin. We show that IRF-1 down-regulates cyclin B1, cdc-2, cyclin E, E2F1, Cdk2, Cdk4, and results in p21-mediated G1 cell cycle arrest. Interestingly, while p21 directly mediates G1 cell cycle arrest, IRF-1 or other IRF-1 signaling pathways may directly regulate survivin in human cancer cells.

Increased cytokine response of rhinovirus-infected airway epithelial cells in chronic obstructive pulmonary disease.

RATIONALE: Airway inflammation is a central feature of chronic obstructive pulmonary disease (COPD). COPD exacerbations are often triggered by rhinovirus (RV) infection. OBJECTIVES: We hypothesized that airway epithelial cells from patients with COPD maintain a proinflammatory phenotype compared with control subjects, leading to greater RV responses. METHODS: Cells were isolated from tracheobronchial tissues of 12 patients with COPD and 10 transplant donors. Eight patients with COPD had severe emphysema, three had mild to moderate emphysema, and one had no emphysema. All had moderate to severe airflow obstruction, and six met criteria for chronic bronchitis or had at least one exacerbation the previous year. Cells were grown at air-liquid interface and infected with RV serotype 39. Cytokine and IFN expression was measured by ELISA. Selected genes involved in inflammation, oxidative stress, and proteolysis were assessed by focused gene array and real-time polymerase chain reaction. MEASUREMENTS AND MAIN RESULTS: Compared with control subjects, cells from patients with COPD demonstrated increased mRNA expression of genes involved in oxidative stress and the response to viral infection, including NOX1, DUOXA2, MMP12, ICAM1, DDX58/RIG-I, STAT1, and STAT2. COPD cells showed elevated baseline and RV-stimulated protein levels of IL-6, IL-8/CXCL8, and growth-related oncogene-alpha/CXCL1. COPD cells demonstrated increased viral titer and copy number after RV infection, despite increased IL-29/IFN-lambda1, IL-28A/IFN-lambda2, and IFN-inducible protein-10/CXCL10 protein levels. Finally, RV-infected COPD cultures showed increased mRNA expression of IL28A/IFNlambda2, IL29/IFNlambda1, IFIH1/MDA5, DDX58/RIG-I, DUOX1, DUOX2, IRF7, STAT1, and STAT2. CONCLUSIONS: Airway epithelial cells from patients with COPD show higher baseline levels of cytokine expression and increased susceptibility to RV infection, despite an increased IFN response.

Lung transplantation in older patients?

OBJECTIVE: Age 65 years and older is generally considered a contraindication to lung transplantation. Our group has offered lung transplantation to select patients 65 years of age and older who lack other comorbid conditions. We sought to define the short- and medium-term outcome of lung transplantation in patients aged 65 years and older. METHODS: We reviewed the records of our lung transplant recipients from March 2000 to September 2006. During this interval, 50 patients were 65 years or older at the time of transplantation. Fifty patients younger than 65 years were matched to the older cohort by means of propensity analysis. The demographics and perioperative and postoperative characteristics and survival of the 2 groups were compared. RESULTS: Older patients were more likely to receive single-lung transplantation (older group: 76% vs younger group: 16%, P < .05) and nonstandard donor lungs (older group: 46% vs younger group: 28%, P = .06). The composite in-hospital morbidity rate was similar in the older and younger groups. There was no significant difference in the early oxygenation parameters, incidence of acute cellular rejection, or incidence of bronchiolitis obliterans syndrome between the 2 groups. The early survival of the older patients was 95.7% compared with 95.9% in the younger cohort (P = .73). The 1-year survival of the 2 groups was also similar (older group: 79.7% vs younger group: 91.2%, P = .16). The 3-year survival of the older and younger recipients was 73.6% and 74.2%, respectively (P = .64). There were 8 deaths in the older recipient group during the 1-month to 1-year posttransplantation interval, predominantly because of infections. CONCLUSIONS: Lung transplantation can be performed in patients older than 65 years with acceptable clinical outcomes. The "increased" mortality of older patients between 1 month and 1 year after transplantation, predominantly from infectious causes, might be due to immunosenescence of older patients. This finding warrants adjustments in the immunosuppression protocol of older patients undergoing lung transplantation. The effect of offering lung transplantation to older patients on donor lung availability deserves further investigation.

Altered trafficking of Fas and subsequent resistance to Fas-mediated apoptosis occurs by a wild-type p53 independent mechanism in esophageal adenocarcinoma.

BACKGROUND: Decreased cell-surface expression of Fas (CD95) results in resistance to Fas-mediated apoptosis in esophageal adenocarcinoma (EA). Because p53 is known to increase transcription of Fas and also may induce trafficking of the protein to the plasma membrane, we investigated whether the loss of wild-type (wt)-p53 function accounts for our previous findings. MATERIALS AND METHODS: Surgical specimens of Barrett's Esophagus containing areas of dysplasia were immunostained for p53 and Fas protein expression. Three EA cell lines were transfected with a wt-p53 containing adenovirus to examine the effects of p53 overexpression. The p53 status of these EA cell lines was determined by sequence analysis. RESULTS: Regions of dysplasia where p53 protein accumulation was observed corresponded to areas of loss of Fas expression. Sequence analysis of the p53 coding sequence in three EA cell lines (Seg-1, Bic-1, and Flo-1) that retain Fas protein within the cytoplasm, demonstrated that Seg-1 contained wt-p53, but mutations were found in Flo-1 and Bic-1 cell lines. Adenoviral transduction of the cell lines with wt-p53 resulted in cell growth arrest in Seg-1 and Bic-1 and induced cell death in Flo-1, but did not result in an increase in Fas protein expression, cell-surface expression, or restoration of sensitivity to Fas-mediated apoptosis. CONCLUSIONS: These data suggest that decreased cell-surface expression of Fas and resistance to Fas-mediated apoptosis may occur independently of loss of wt p53 expression.

Carbon monoxide inhibits T lymphocyte proliferation via caspase-dependent pathway.

T lymphocyte activation and proliferation is involved in many pathological processes. We have recently shown that carbon monoxide (CO), an enzymatic product of heme oxygenase-1 (HO-1), confers potent antiproliferative effects in airway and vascular smooth muscle cells. The purpose of this study was to determine whether CO can inhibit T lymphocyte proliferation and then to determine the mechanism by which CO can modulate T lymphocyte proliferation. In the presence of 250 parts per million CO, CD3-activated T lymphocyte proliferation was, remarkably, inhibited by 80% when compared with controls. We observed that the antiproliferative effect of CO in T lymphocytes was independent of the mitogen-activated protein kinase or cGMP signaling pathways, unlike what we demonstrated previously in smooth muscle cells. We demonstrate that CO inhibited caspase-3 and caspase-8 expression and activity, and caspase inhibition with benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK pan-caspase inhibitor) blocked T lymphocyte proliferation. Furthermore, in caspase-8-deficient lymphocytes, the antiproliferative effect of CO was markedly attenuated, further supporting the involvement of caspase-8 in the antiproliferative effects of CO. CO also increased the protein level of p21(Cip1), and CO-mediated inhibition of caspase activity is partially regulated by p21(Cip1). Taken together, these data suggest that CO confers potent antiproliferative effects in CD3-activated T lymphocytes and that these antiproliferative effects in T lymphocytes are mediated by p21(Cip1)-dependent caspase activity, in particular caspase-8, independent of cGMP and mitogen-activated protein kinase signaling pathways.

Overexpression of mutated IkappaBalpha inhibits vascular smooth muscle cell proliferation and intimal hyperplasia formation.

PURPOSE: Vascular injury and inflammation are associated with elaboration of a number of cytokines that signal through multiple pathways to act as smooth muscle cell (SMC) mitogens. Activation of the nuclear factor-kappa B (NF-kappaB) transcription factor is essential for SMC proliferation in vitro and is activated by vascular injury in vivo. Activation of NF-kappaB is controlled by several upstream regulators, including the inhibitors of kappa B (IkappaB). These proteins bind to and keep NF-kappaB inactivated. The purpose of this study was to determine whether adenoviral gene transfer of a mutated IkappaBalpha super-repressor (AdIkappaBalphaSR) could inhibit development of intimal hyperplasia in vivo and to investigate how over-expression of this construct influences in vitro SMC proliferation and cell cycle regulatory proteins. METHODS: A rat carotid injury model was used to study prevention of intimal hyperplasia. Arteries were assayed 14 days after injury and infection with AdIkappaBalphaSR or adenoviral beta-galactosidase (AdLacZ). Untreated SMC or SMC infected with AdLacZ or AdIkappaBalphaSR were stimulated with 10% fetal bovine serum, interleukin-1beta, or tumor necrosis factor-alpha. Electrophoretic mobility shift assays were used to assay for NF-kappaB activation. Protein levels of IkappaBalpha and cyclin-dependent kinase inhibitors p21(Cip1/Waf1) and p27(Kip1) were determined with Western blot analysis. Proliferation was measured with (3)H-thymidine incorporation assays. RESULTS: AdIkappaBalphaSR inhibited the development of intimal hyperplasia by 49% (P <.05). Infection with AdIkappaBalphaSR significantly suppressed in vitro SMC proliferation when stimulated with serum, interleukin 1, or tumor necrosis factor alpha, and did not result in cell death. Inhibition of proliferation was associated with increased p21(Cip1/Waf1) and p27(Kip1) protein levels. CONCLUSIONS: Gene transfer of IkappaBalpha super-repressor inhibited development of intimal hyperplasia in vivo and SMC proliferation in vitro. The antiproliferative activity may be related to cell cycle arrest through upregulation of the cyclin-dependent kinase inhibitors p21 and p27. Overexpression of IkappaBalpha may be a future therapeutic option in treatment of vascular diseases.

Nitric oxide-mediated inhibition of caspase-dependent T lymphocyte proliferation.

Nitric oxide (NO), a pleiotropic signaling molecule produced at sites of inflammation, is a powerful inhibitor of lymphocyte proliferation. Caspases, central effector proteases in apoptosis, have recently been implicated as critical mediators of T cell activation. We and others have shown that NO can inhibit caspases by S-nitrosylation, which is reversible by the reducing agent dithiothreitol (DTT). The purpose of the present study was to determine whether NO inhibits lymphocyte proliferation by modulating caspase activity. Caspase inhibition with z-VAD-fmk blocked T cell proliferation. NO-dependent inhibition of T cell proliferation was associated with an inhibition of caspase activity and activation, and this effect was reversible by DTT. Previous studies demonstrated inhibition of apoptosis through S-nitrosylation of caspases; the present studies extend this effect to inhibition of caspase-dependent T cell proliferation.