Encouraging results of blood conservation in neonatal open-heart surgery.

OBJECTIVE: To report early outcomes of blood conservation in neonatal open-heart surgery. METHODS: Ninety-nine patients undergoing neonatal open-heart surgery during the implementation of a blood conservation program between May 2021 and February 2023 were reviewed. Patients either received traditional blood management (blood prime, n = 43) or received blood conservation strategies (clear prime, n = 56). Baseline characteristics and outcomes were compared between groups. RESULTS: There was no difference in body weight (median, 3.2 kg vs 3.3 kg; P = .83), age at surgery (median, 5 days vs 5 days; P = .37), distribution of The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery Mortality Categories categories or duration of cardiopulmonary bypass. Patients in the clear prime group had higher preoperative hematocrit (median, 41% vs 38%; P < .01), shorter postoperative mechanical ventilation time (median, 48 hours vs 92 hours; P = .02) and postoperative intensive care unit length of stay (median, 6 days vs 9 days; P < .01) than patients in the blood prime group. Fourteen patients (25%) in the clear prime group, including 1 Norwood patient, were discharged without any transfusion. Among patients within the clear prime group, hospitalizations without blood exposure were associated with higher preoperative hematocrit (median, 43% vs 40%; P = .02), shorter postoperative mechanical ventilation times (median, 22 hours vs 66 hours; P = .01) and shorter postoperative hospital stays (median, 10 days vs 15 days; P = .02). CONCLUSIONS: Bloodless surgery is possible in a significant proportion of neonates undergoing open-heart surgery, including the Norwood operation, even in the early stages of experience. Early clinical results are favorable but long-term follow-up and continued efforts are warranted to prove safety and reproducibility.

Dissemination and implementation analysis of the Ross procedure in adults: time to update the guidelines?

Background: The science of dissemination and implementation (D&I) aims to improve the quality and effectiveness of care by addressing the challenges of incorporating research and evidence-based practice into routine clinical practice. This lens of D&I has challenged the interpretation and incorporation of data, noting that failure of a given therapy may not reflect lack of efficacy, but instead reflect an imperfect implementation. The aim of this manuscript is to review the influence of the Ross procedure's historical context on its D&I. Methods: A contextual baseline of the Ross procedure was defined from the procedure's original description in the literature to major publications since the 2017 valvular heart disease guidelines. D&I evaluation was conducted using the Consolidated Framework for Implementation Research (CFIR), using constructs from each of the five respective domains to define the main determinants. Results: Each of the five CFIR domains appears to be correlated with a factor influencing the Ross procedure's varied history of enthusiasm and acceptance. The complex nature of Ross required adaptation for optimization, with a strong correlation of center volume on outcomes that were not considered in non-contemporary studies. Outcomes later published from those studies influenced social and cultural contexts within the aortic surgery community, and led to further organizational uncertainty, resulting in slow guideline incorporation. Conclusions: The D&I of the Ross procedure was a result of inadequate appreciation of technical complexity, effect of patient selection, and complex aortic surgery experience, resulting in dismissal of an efficacious procedure due to a misunderstanding of effectiveness.

The Genetically Engineered Heart as a Bridge to Allotransplantation in Infants Just Around the Corner?

BACKGROUND: Mortality for infants on the heart transplant waitlist remains unacceptably high, and available mechanical circulatory support is suboptimal. Our goal is to demonstrate the feasibility of utilizing genetically engineered pig (GEP) heart as a bridge to allotransplantation by transplantation of a GEP heart in a baboon. METHODS: Four baboons underwent orthotopic cardiac transplantation from GEP donors. All donor pigs had galactosyl-1,3-galactose knocked out. Two donor pigs had human complement regulatory CD55 transgene and the other 2 had human complement regulatory CD46 and thrombomodulin. Induction immunosuppression included thymoglobulin, and anti-CD20. Maintenance immunosuppression was rapamycin, anti-CD-40, and methylprednisolone. One donor heart was preserved with University of Wisconsin solution and the other three with del Nido solution. RESULTS: All baboons weaned from cardiopulmonary bypass. B217 received a donor heart preserved with University of Wisconsin solution. Ventricular arrhythmias and depressed cardiac function resulted in early death. All recipients of del Nido preserved hearts easily weaned from cardiopulmonary bypass with minimal inotropic support. B15416 and B1917 survived for 90 days and 241 days, respectively. Histopathology in B15416 revealed no significant myocardial rejection but cellular infiltrate around Purkinje fibers. Histopathology in B1917 was consistent with severe rejection. B37367 had uneventful transplant but developed significant respiratory distress with cardiac arrest. CONCLUSIONS: Survival of B15416 and B1917 demonstrates the feasibility of pursuing additional research to document the ability to bridge an infant to cardiac allotransplant with a GEP heart.

Surgical Management of Heterotaxy Syndrome: Current Challenges and Opportunities.

INTRODUCTION: Heterotaxy syndrome presents a unique challenge in surgical management, even in the current era. We hypothesized that certain anatomic subsets merit novel strategies. METHODS: We analyzed morphologic details, surgeries, comorbidities, subsequent admissions, and survival using Kaplan-Meier methods and multivariable risk models from a single-institution experience of 103 consecutive patients with heterotaxy who underwent cardiac surgery between January 1, 1990, and May 31, 2016. RESULTS: Of the 103 patients (50 males and 53 females), 31 had left atrial isomerism, 64 had right atrial isomerism (RAI), and 8 patients' isomerism was indeterminate (IND), with first cardiac operation at a mean 1.0 year (standard deviation ±3.0 years) of age. Kaplan-Meier overall survival estimate was 83.1% at six months, 77.8% at one year, 65.9% at five years, and 52.1% at ten years. Survival was particularly low among RAI following repair of total anomalous pulmonary venous connection (TAPVC) at first operation, with one- and five-year survival of 57% and 46%, respectively. By multivariable analysis, the only risk factor for death during the early phase (hazard model) was repair of TAPVC at the first cardiac operation (hazard ratio [HR]: 4.4, P = .01), and risk factors during the longer term constant phase were atrioventricular valve (AVV) regurgitation (HR: 4.2, P < .01), male gender (HR: 3.7, P < .01), and two-ventricle repair (HR: 3.0, P = .02). Patients with heterotaxy undergoing the Fontan procedure had excellent subsequent survival (85% at ten years). CONCLUSIONS: This analysis of over 100 patients with heterotaxy identified TAPVC requiring initial repair as the major risk factor for early death and important AVV regurgitation as the major risk factor in the longer term. Survival with RAI and early repair of TAPVC were poor, with one-year mortality exceeding 40%. Patients with single ventricle completing the Fontan operation enjoyed outstanding ten-year survival (85%). Initial management of RAI requiring early repair of TAPVC remains challenging. For this high-risk subset, alternative strategies such as early referral for cardiac transplantation evaluation warrant consideration.

Repair of Rare Vascular Ring: Circumflex Aortic Arch with Associated Hypoplasia and Coarctation.

We describe a neonate with an unusual vascular ring formed by a right-sided aortic arch with associated coarctation and distal hypoplasia in the presence of an aberrant left subclavian artery. The descending aorta traveled behind the esophagus to descend on the left side of the spine. A left ductus arteriosus connected to the descending aorta completing the vascular ring, with notable esophageal compression. Surgical correction was accomplished through median sternotomy, resection of the hypoplastic circumflex arch, aortic arch advancement, and end-to-side anastomosis.

Anti-Pig Antibody in Infants: Can a Genetically Engineered Pig Heart Bridge to Allotransplantation?

BACKGROUND: Patients with congenital heart disease have high heart transplant waitlist mortality, and mechanical support is suboptimal. To evaluate feasibility of cardiac grafts from a genetically engineered triple-knockout pig as a bridge to allotransplantation, preformed anti-pig antibodies were measured in pediatric and adult patients. METHODS: Flow cytometry measured serum immunoglobulin M (IgM) or IgG binding to wild-type and triple-knockout red blood cells (RBCs), with binding to human O-negative RBCs as a negative control. Group 1 comprise 84 pediatric patients and 64 healthy adults' sera with no previous cardiac surgery. Group 2 comprised 25 infant's sera postcardiac surgery, including 10 after palliation for hypoplastic left heart syndrome. RESULTS: In group 1, IgM binding to wild-type RBCs occurred in 80% of sera and IgG binding occurred in in 91% of sera. Only 3% of sera showed IgM binding to triple-knockout RBCs, and 1 (<1%) was weakly positive for IgG binding. In group 2, all 25 infants demonstrated increased IgM and IgG binding to wild-type RBCs. One patient showed minimal IgM and another showed low IgG binding to triple-knockout RBCs. No infant after stage 1 Norwood demonstrated any IgG or IgM binding. CONCLUSIONS: Preformed anti-pig antibodies may not be a barrier to heart xenotransplantation in infants, even after cardiac surgery. With adequate immunosuppressive therapy, a triple-knockout pig heart transplant might function successfully as a bridge to allotransplantation.

Evaluation of Cardiothoracic Surgery Residency and Fellowship Program Websites.

BACKGROUND: The internet is a valuable resource for residency and fellowship applicants when deciding where to apply or interview, yet program websites have shown critical deficiencies in accessibility and content. No analysis of cardiothoracic surgery program websites has been performed. METHODS: Online databases and Google were used to identify integrated, 4 + 3, and traditional cardiothoracic surgery residency and fellowship programs. The accessibility of websites from each of these sources was assessed and the presence or absence of content that may be relevant to applicants was evaluated by two reviewers. RESULTS: Eighty-nine active programs were identified and 86 had functional websites. Website content and accessibility were overall suboptimal in all 86 of these programs. Google was the most reliable means of accessing a program's website. Fifty percent of integrated program websites and 60% of traditional fellowship websites contained less than half of the content assessed. Information on 4 + 3 programs was extremely limited. CONCLUSIONS: Despite the value that a program's website could provide to applicants when making decisions during the application process, cardiothoracic surgery residency and fellowship websites remain difficult to access and are not uniformly providing information that may be important. Improving cardiothoracic website accessibility and content may have implications for attracting the most competitive applicants while limiting the financial and scheduling demands associated with the interview process. Creation of a current database containing standardized information relevant to applicants may improve applicants' ability to form an impression of a program before scheduling an interview.

Left ventricular myxoma: A contractile mass causing intracavitary obstruction and severe pulmonary hypertension.

Cardiac myxomas can be fatal and left ventricular (LV) myxomas with papillary muscle and mitral valve (MV) involvement are rare. The following case is that of a 55-year-old woman who developed signs and symptoms of pulmonary hypertension. Imaging revealed a contractile mass in the LV that was in continuum with the papillary muscles and affected MV function. Her clinical course, radiologic, and hemodynamic findings are discussed. Finally, her surgical extraction technique is described in addition to potential complications encountered.

Congenitally Corrected Transposition Presenting in the First Year of Life: Survival and Fate of the Systemic Right Ventricle.

INTRODUCTION: Knowledge gaps exist in the life expectancy and functional outcome of patients with congenitally corrected transposition (ccTGA) presenting early in life, which is relevant in the evaluation of early anatomic repair. METHODS: In a single-center analysis, 91 patients with ccTGA were identified over 25 years, of which 31 presented with biventricular anatomy in the first year of life and formed the study cohort. End points for analysis included survival, moderate or worse tricuspid valve regurgitation, and systemic right ventricle (RV) dysfunction. Median follow-up was 4.9 years (range: 7 days to 20 years). RESULTS: Among 31 patients presenting in the first year of life, 9 (29%) never received cardiac surgery, while 22 (71%) underwent 36 cardiac operations. Overall freedom from moderate or severe systemic RV dysfunction was 75% at 10 years. Overall survival was 82% at 10 years. Surgical mortality was 5.6% (2/36). Among survivors with a systemic RV, 23 (100%) of 23 were Ross or NYHA class I or II at last follow-up. CONCLUSIONS: Congenitally corrected transposition presenting in the first year of life and maintaining a systemic RV can expect (1) long-term survival of more than 80% at 10 years, (2) low expected surgical mortality (overall 6%), and (3) 75% late freedom from major RV dysfunction at 10 years. Pending multi-institutional analyses, this experience with a systemic RV in ccTGA provides an initial benchmark for comparison when considering early elective anatomic correction.

Transplantation in the Fontan patient.

The failing Fontan circulation presents difficult treatment challenges. When Fontan revision and or intervention for treatable arrhythmias is not feasible, heart transplantation is the only therapeutic option. Particular challenges presented by these patients include limited ability to assess hemodynamics, complex anatomy, multiple prior procedures, and unique underlying pathologic states. These issues complicate the decision-making process for further surgical intervention verses transplantation. The pre-transplant evaluation, transplant operation, and post-operative management are more problematic for these patients compared with most patients undergoing transplantation. Consequently, failing Fontan patients constitute one of the highest risk heart transplant subsets.

Current estimate of costs of lung cancer screening in the United States.

The United States Preventive Services Task Force recently endorsed the use of low-dose computed tomography for lung cancer screening in high-risk patients because of the potential to reduce deaths. Before implementation on a national level, it will be important to ensure that a safe, high-quality, and accessible service can be adequately provided. It will also be important to make sure that screening is cost-effective. This article summarizes the published analyses of lung cancer screening cost, provides a contemporary estimation of the annual cost of screening in the United States, and identifies areas for improvement in the future.

Cancer stem cell phenotype is supported by secretory phospholipase A2 in human lung cancer cells.

BACKGROUND: Lung cancer stem cells (CSCs) are a subpopulation of cells that drive growth, invasiveness, and resistance to therapy. Inflammatory eicosanoids are critical to maintain this malignant subpopulation. Secretory phospholipase A2 group IIa (sPLA2) is an important mediator of the growth and invasive potential of human lung cancer cells and regulates eicosanoid production. We hypothesized that sPLA2 plays a role in the maintenance of lung CSCs. METHODS: Cancer stem cells from lung adenocarcinoma cell lines H125 and A549 were isolated using aldehyde dehydrogenase activity and flow cytometry. Protein and mRNA levels for sPLA2 were compared between sorted cells using Western blotting and quantitative reverse transcriptase-polymerase chain reaction techniques. Chemical inhibition of sPLA2 and short-hairpin RNA knockdown of sPLA2 were used to evaluate effects on tumorsphere formation. RESULTS: Lung CSCs were isolated in 8.9%±4.1% (mean±SD) and 4.1%±1.6% of H125 and A549 cells respectively. Both sPLA2 protein and mRNA expression were significantly elevated in the CSC subpopulation of H125 (p=0.002) and A549 (p=0.005; n=4). Knockdown of sPLA2 significantly reduced tumorsphere formation in H125 (p=0.026) and A549 (p=0.001; n=3). Chemical inhibition of sPLA2 resulted in dose-dependent reduction in tumorsphere formation in H125 (p=0.003) and A549 (p=0.076; n=3). CONCLUSIONS: Lung CSCs express higher levels of sPLA2 than the non-stem cell population. Our findings that viral knockdown and chemical inhibition of sPLA2 reduce tumorsphere formation in lung cancer cells demonstrate for the first time that sPLA2 plays an important role in CSCs. These findings suggest that sPLA2 may be an important therapeutic target for human lung cancer.

Knockdown of secretory phospholipase A2 IIa reduces lung cancer growth in vitro and in vivo.

OBJECTIVE: Group IIa secretory phospholipase A2 (sPLA2 IIa) plays a role in the malignant potential of several epithelial cancers. Nuclear factor kappa B (NF-κB) regulates cancer cell growth and is modulated by phospholipase activity in many cancer cells. We hypothesized that knockdown of sPLA2 in lung cancer cells would reduce cell proliferation and NF-κB activity in vitro and attenuate tumor growth in vivo. METHODS: Two human non-small cell lung cancer cell lines (A549 and H358) were transduced with short hairpin RNA targeting sPLA2 group IIa. Quantitative reverse transcriptase-polymerase chain reaction and immunoblotting confirmed knockdown of sPLA2 IIa messenger RNA and protein, respectively. Cell proliferation was evaluated by the 5-bromo-2'-deoxyuridine DNA labeling assay. NF-κB phosphorylation was assayed by western blot. 1 × 10(6) of A549 or A549 sPLA2 knockdown cells were injected into the left flanks of nude mice (aged 6 to 8 weeks). Tumors were followed for 23 days, then removed and stained with hematoxylin and eosin, stained with Ki-67, and analyzed for sPLA2 IIa messenger RNA expression. RESULTS: sPLA2 knockdown reduced NF-κB phosphorylation and tumor growth in vivo. A549 wild-type tumors grew twice as fast as knockdown tumors. Ki-67 staining was more prominent throughout the wild-type tumors compared with knockdown tumors. Explanted knockdown tumors maintained lower sPLA2 levels compared with wild-type, confirmed by reverse transcriptase-polymerase chain reaction. CONCLUSIONS: Knockdown of sPLA2 IIa suppresses lung cancer growth in part by attenuating NF-κB activity. These findings justify further investigation into the cellular mechanisms of sPLA2 in lung cancer and its potential role as a therapeutic target.

Pulmonary resection and lung transplantation for bronchiectasis.

The purpose of this article is to update specialists in pulmonary medicine on the role of surgical resection and lung transplantation for bronchiectasis. The focus is on pre-operative workup, the technical details of surgical resection, complications, and outcomes.

Microfilaments facilitate TLR4-mediated ICAM-1 expression in human aortic valve interstitial cells.

BACKGROUND: Inflammation is involved in the pathogenesis of calcific aortic valve stenosis, and aortic valve interstitial cells (AVICs) play an important role in valve disease and remodeling. We have previously shown that human AVICs express functional toll-like receptor 4 (TLR4), and express increased levels of ICAM-1 in response to stimulation with bacterial lipopolysaccharide (LPS). This study examines (1) the role of TLR4 in regulating ICAM-1 expression in human AVICs, (2) the interaction of ICAM-1 with microfilaments, and (3) the influence of microfilament integrity on ICAM-1 expression. MATERIALS AND METHODS: AVICs isolated from explanted human hearts were stimulated with LPS (0.2 µg/mL) to induce ICAM-1 expression, as shown by Western blot. TLR4 activity was influenced with a neutralizing antibody or by gene knockdown with siRNA. Flow cytometry and immunofluorescence were used to characterize membrane localization of ICAM-1. Immunoprecipitation and immunofluorescence were employed to show colocalization of ICAM-1 with microfilaments. Microfilament function was influenced with an actin polymerization inhibitor as well as siRNA. RESULTS: Cellular ICAM-1 levels increased 10-fold after 24 h of LPS stimulation, and this increase was significantly attenuated by prior treatment with TLR4-neutralizing antibody or TLR4 siRNA. ICAM-1 exhibited a filamentous distribution pattern after 4 h LPS stimulation, which was associated with increased total and cell-surface ICAM-1 expression. ICAM-1 colocalized and coprecipitated with the microfilament proteins F-actin and α-actinin 1. Pretreatment with the actin polymerization inhibitor latrunculin B and silencing α-actinin 1 with siRNA reduced LPS-induced total and cell-surface ICAM-1 expression. CONCLUSIONS: This study demonstrates that (1) LPS-stimulated ICAM-1 expression in human AVICs is mediated by TLR4, (2) ICAM-1 interacts with microfilaments soon after LPS stimulation, and (3) microfilament disruption reduces ICAM-1 expression. These results suggest that the interaction between ICAM-1 and microfilaments facilitates LPS-induced ICAM-1 expression in human AVICs.

Heat shock protein 27: induction by gastroduodenal reflux in vivo and augmentation of human esophageal mucosal cell growth in vitro.

OBJECTIVE: Acid exposure to esophageal epithelium leads to hyperplasia and mucosal thickening. This is associated with upregulation of antiapoptotic genes. Recently, heat shock proteins have been implicated in esophageal mucosal response to stress. We sought to determine the influence of gastroduodenal reflux on esophageal mucosal heat shock protein 27 gene (murine analog Hspb1, human HSPB1) expression in vivo and the effect of HSPB1 overexpression on proliferation of esophageal mucosal cells in vitro. METHODS: Balb/c mice underwent either anastomosis of gastroesophageal junction and first portion of duodenum to induce continuous gastroduodenal reflux (n = 14) or sham procedure (n = 12). Quantitative reverse transcriptase polymerase chain reaction was used to determine the influence of gastroduodenal reflux on Hspb1 expression. Immunofluorescent microscopy and immunoblotting were used to quantify changes in heat shock protein 27 protein expression. Lentiviral infection techniques were used to overexpress HSPB1 in human esophageal epithelial cells. Both 3-(4,5-dimethylthiazole-2-yl) 2,5,-diphenyl tetrazolium bromide and 5-bromo-2-deoxyuridine incorporation assays were used to assess cell proliferation. RESULTS: Expressions of Hspb1 and its protein product were increased in esophageal tissue after 12 weeks' reflux relative to sham control group. Expression was located mainly in hyperplastic epithelial cells. Overexpression of HSPB1 in human esophageal epithelial cells resulted in increased proliferation. CONCLUSIONS: Heat shock protein 27 is upregulated in response to gastroduodenal reflux and is a mediator of human esophageal epithelial cell proliferation and growth. This novel finding illustrates the importance of its expression in the development of inflammation and mucosal thickening associated with esophageal reflux.

Modulation of growth in human esophageal adenocarcinoma cells by group IIa secretory phospholipase A(2).

OBJECTIVE: Esophageal adenocarcinoma is thought to arise from lesions produced by chronic esophageal inflammation. Secretory phospholipase A(2) is an important mediator of mucosal response to gastroesophageal reflux, but its role in the function of mature cancer cells is unclear. We sought to determine the influence of group IIa secretory phospholipase A(2) on proliferation of human esophageal adenocarcinoma cells. METHODS: FLO-1 and OE33 cells derived from human esophageal adenocarcinoma were cultured with standard techniques. Cells were treated with 1-, 5-, 10-, and 20-mumol/L doses of 5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino)pentanoic acid, a specific inhibitor of group IIa secretory phospholipase A(2), for 72 hours. Gene for group IIa secretory phospholipase A(2)(PLA2G2A) was overexpressed and silenced with lentiviral infection techniques. Cell proliferation and viability were measured with standard 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide and bromodeoxyuridine incorporation assays. All assays were performed in triplicate. PLA2G2A expression was measured with quantitative reverse transcriptase polymerase chain reaction; protein levels were detected with immunofluorescence microscopy. Statistical analysis was by analysis of variance with Fisher post hoc analysis. RESULTS: Secretory phospholipase A(2) protein was found in both malignant esophageal adenocarcinoma cell lines. Treatment with specific group IIa secretory phospholipase A(2) inhibitor resulted in dose-dependent reductions in growth and cell number in both cell lines. Overexpression of PLA2G2A resulted in enhanced cancer cell growth, whereas gene knockdown attenuated growth. CONCLUSIONS: Group IIa secretory phospholipase A(2) appears significant in growth and proliferation of human esophageal adenocarcinoma cells. Secretory phospholipase A(2) inhibition should be studied further regarding potential chemopreventive and therapeutic properties in esophageal adenocarcinoma.

Bone morphogenic protein 2 induces Runx2 and osteopontin expression in human aortic valve interstitial cells: role of Smad1 and extracellular signal-regulated kinase 1/2.

OBJECTIVE: Bone morphogenic protein 2 is found in calcified areas of stenotic aortic valves, and prolonged stimulation of aortic valve interstitial cells with bone morphogenic protein 2 results in increased expression of alkaline phosphatase, indicating a mechanistic role for bone morphogenic protein 2 in aortic valve calcification. The purposes of this study were to assess the effect of bone morphogenic protein 2 on the expression of the osteogenic factors Runx2 and osteopontin in human aortic valve interstitial cells and to determine the signaling mechanisms that mediate the expression of these early osteogenic factors. METHODS: Interstitial cells were isolated from normal and stenotic human aortic valve leaflets, and cellular bone morphogenic protein 2 levels were analyzed by means of immunoblotting. Cultured interstitial cells from normal aortic valves were stimulated with bone morphogenic protein 2 to determine its effect on cellular Runx2 and osteopontin levels. RESULTS: Interstitial cells from stenotic aortic valves express greater levels of bone morphogenic protein 2 than cells from normal valves. Stimulation of human aortic valve interstitial cells with bone morphogenic protein 2 induced marked increases in Runx2 and osteopontin levels at 48 hours. The changes in Runx2 and osteopontin levels were preceded by phosphorylation of Smad1 and extracellular signal-regulated kinase 1/2 but not p38 mitogen-activated protein kinase. Silencing Smad1 reduced Runx2 and osteopontin levels, whereas inhibition of extracellular signal-regulated kinase 1/2 reduced osteopontin expression without an influence on Runx2 expression. CONCLUSIONS: Interstitial cells of stenotic human aortic valves are characterized by increased bone morphogenic protein 2 levels. A short period of exposure of human aortic valve interstitial cells to bone morphogenic protein 2 induces the expression of Runx2 and osteopontin. The extracellular signal-regulated kinase 1/2 pathway modulates bone morphogenic protein 2-induced osteopontin expression, and the Smad1 pathway plays a role in regulating the expression of both Runx2 and osteopontin induced by bone morphogenic protein 2.