Biomedical subjects

Walter Klepetko

Publications and source records attributed to Walter Klepetko.

At least 19 recordsLinked to original sources

PubMed2007

Institutional experience with extracorporeal membrane oxygenation in lung transplantation.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is currently accepted in lung transplantation either to bridge patients to transplantation or to treat postoperatively arising severe primary graft failure. Based on promising initial experiences we have since 2001 implemented ECMO as the standard of intraoperative extracorporeal support in lung transplantation (LuTX) patients with haemodynamic or respiratory instability with the potential to prolong ECMO support into the perioperative period. The aim of this paper is to summarise our total experience with the use of ECMO in LuTX. METHODS: We retrospectively reviewed all 306 patients undergoing primary lung transplantation from 1/2001 to 1/2006 with regard to the different forms of ECMO use. Results of all patients requiring ECMO were compared to those without ECMO during the observation period. RESULTS: ECMO was used in 147 patients in total. Two patients were bridged to transplantation. A total of 130 patients received intraoperative ECMO support. In 51 of these patients ECMO was prolonged into the perioperative period. Five of these patients required ECMO support again in the postoperative period due to graft dysfunction. Contrary cardiopulmonary bypass was used in 27 patients mainly with concomitant cardiac defects. Eleven of these patients needed therapeutic ECMO in the further course. A total of 149 patients without relevant risk factors were transplanted without any intraoperative extracorporeal support. Six of these patients required ECMO support in the postoperative period for treatment of primary graft dysfunction. Overall 3-month, 1-year and 3-year survival rates were 88.6%, 82.1% and 74.63%. The mentioned survival rates were 85.4%, 74.2% and 67.6% in the intraoperative+/-prolonged ECMO group; 93.5%, 91.9% and 86.5% in the no support group and 74.0%, 65.9% and 57.7% in the CPB group. CONCLUSION: ECMO is a valuable tool in lung transplantation providing the potential to bridge patients to transplantation, to replace CPB with at least equal results and to overcome severe postoperative complications. Favourable survival rates can be achieved despite the fact that ECMO is used in the more complex patient population undergoing lung transplantation as well as to overcome already established severe complications.

Adult↗

PubMed2006

Relationship between cytomegalovirus DNA load in epithelial lining fluid and plasma of lung transplant recipients and analysis of coinfection with Epstein-Barr virus and human herpesvirus 6 in the lung compartment.

Cytomegalovirus (CMV) is a significant cause of morbidity and mortality in lung transplant recipients (LTRs). The aim of the present study was to elucidate the relationship between the CMV DNA load in the lung compartment and that in plasma. For CMV load determination, the level of CMV DNA in plasma and bronchoalveolar lavage (BAL) samples was measured in a total of 97 paired BAL and plasma samples obtained from 25 LTRs. The original virus concentration in the epithelial lining fluid (ELF) was calculated from the BAL samples by correcting for dilution using the urea dilution method. In addition, the load of Epstein-Barr virus (EBV) and that of human herpesvirus 6 (HHV-6) DNA also were determined in BAL samples, recalculated for their concentrations in the ELF, and compared with the CMV DNA load. CMV DNA was found more frequently and at significantly higher levels in the lung compartment than in plasma (P<0.001, Wilcoxon test), and the CMV load in the ELF was associated with symptomatic CMV disease. EBV and HHV-6 were detected in 43.6% and 21.7% of the ELF samples, respectively. A statistically significant association was found between the CMV and EBV DNA loads in the ELF (P<0.001; Spearman's rho=0.651). Thus, in LTRs, determination of the CMV DNA load in the lung compartment may be advantageous compared to monitoring only viremia. The significant relationship between EBV and CMV DNA loads in the ELF of LTRs and its clinical impact require further investigation.

Adult↗

PubMed2006

Induction chemotherapy with the TIP regimen (paclitaxel/ifosfamide/cisplatin) in stage III non-small cell lung cancer.

Induction chemotherapy may improve clinical outcome of locally advanced non-small cell lung cancer (NSCLC). To further pursue this, the Austrian Association for the Study of Lung Cancer (AASLC) performed a multi-center phase II trial with TIP induction chemotherapy (Taxol 175 mg/m2 over 3h on day 1, ifosfamide 1000 mg/m2 daily on days 1-3, cisplatin 60 mg/m2 on day 1, and prophylactic filgrastim 5 microg/kg daily on days 4-13). Treatment cycles were repeated every 3 weeks for 3 cycles. Then patients were re-staged and selected for local treatment. Forty-seven patients (33 male, 14 female; median age 58 years, range 36-78; 22 cIIIA, 25 cIIIB; 26 adenocarcinomas, 14 squamous cell carcinomas, 4 large cell carcinomas, 3 undifferentiated carcinomas) were included in this trial. Forty-five patients were evaluable for response and toxicity. An overall response rate of 43% (complete remission 4.5% and partial remission 38%) was achieved. Stable disease and progressive disease were seen in 38 and 15% of the patients, respectively. Down-staging occurred in 36% of the patients. The toxicities of the chemotherapy were mild and, in particular, no severe hematotoxicity was observed. Surgery was performed in 24 (51%) patients and resulted in complete tumor resection in 19 patients. Twenty-four patients received thoracic radiotherapy, 10 patients after surgery. Median survival was 10.3 months for the total population, 13.5 months for patients with cIIIA and 10 months for patients with clinical cIIIB. Survival was longer for patients with down-staging as compared to those without (median not reached versus 10 months, p=0.005) and for patients with complete tumor resection as compared to the remaining patients (27 months versus 10 months, p=0.05). In conclusion, the TIP regimen shows activity and good tolerance as induction chemotherapy in patients with locally advanced NSCLC.

Adult↗

PubMed2006

Impact of TASK-1 in human pulmonary artery smooth muscle cells.

The excitability of pulmonary artery smooth muscle cells (PASMC) is regulated by potassium (K+) conductances. Although studies suggest that background K+ currents carried by 2-pore domain K+ channels are important regulators of resting membrane potential in PASMC, their role in human PASMC is unknown. Our study tested the hypothesis that TASK-1 leak K+ channels contribute to the K+ current and resting membrane potential in human PASMC. We used the whole-cell patch-clamp technique and TASK-1 small interfering RNA (siRNA). Noninactivating K+ current performed by TASK-1 K+ channels were identified by current characteristics and inhibition by anandamide and acidosis (pH 6.3), each resulting in significant membrane depolarization. Moreover, we showed that TASK-1 is blocked by moderate hypoxia and activated by treprostinil at clinically relevant concentrations. This is mediated via protein kinase A (PKA)-dependent phosphorylation of TASK-1. To further confirm the role of TASK-1 channels in regulation of resting membrane potential, we knocked down TASK-1 expression using TASK-1 siRNA. The knockdown of TASK-1 was reflected by a significant depolarization of resting membrane potential. Treatment of human PASMC with TASK-1 siRNA resulted in loss of sensitivity to anandamide, acidosis, alkalosis, hypoxia, and treprostinil. These results suggest that (1) TASK-1 is expressed in human PASMC; (2) TASK-1 is hypoxia-sensitive and controls the resting membrane potential, thus implicating an important role for TASK-1 K+ channels in the regulation of pulmonary vascular tone; and (3) treprostinil activates TASK-1 at clinically relevant concentrations via PKA, which might represent an important mechanism underlying the vasorelaxing properties of prostanoids and their beneficial effect in vivo.

Cells, Cultured↗

PubMed2006

Emergence of multiple cytomegalovirus strains in blood and lung of lung transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) is a major pathogen in lung transplant recipients (LTRs). The emergence of different CMV strains in lung and blood after transplantation has not yet been analyzed. METHODS: In total, 75 serum and 91 broncheoalveolar lavage (BAL) samples obtained from 25 LTRs in the follow-up after transplantation were tested for the presence of different CMV strains. The gB, gN, and gO genes of the CMV isolates were analyzed by subtype-specific PCR, restriction fragment length polymorphism (RFLP), sequencing, and phylogenetic analysis. RESULTS: Mixed CMV-strain populations were detected after cessation of antiviral prophylaxis in up to 80% and 90% of the patients' BAL and serum, respectively, and this was independent of the CMV serostatus of donor and recipient. In five patients, the same single CMV strain was consistently detectable over at least 1 year in lung and blood, although in two of these cases donor and recipient had both been CMV-seropositive. Most CMV strains were distributed in the lung and blood compartment. Symptomatic CMV infection within the first year after transplantation was observed only in patients with mixed CMV-strain populations (P<0.05). CONCLUSION: Most LTRs harbor more than one CMV strain in their lung and blood compartment after cessation of prophylaxis, but the CMV strain distribution within and between the compartments varies between individuals and is not associated with the donor/recipient serostatus. The data further show that compartmentalization of CMV strains in lung versus blood seems to be a rare event and that the presence of mixed CMV-strain infections within the first year after transplantation may be disadvantageous for LTRs.

Adolescent↗

PubMed2006

Human RELMbeta is a mitogenic factor in lung cells and induced in hypoxia.

RELMbeta (resistin-like molecule) represents the most related human homologue of mouse RELMalpha, also known as hypoxic-induced mitogenic factor (HIMF). In this study, we isolated RELMbeta cDNA from human lung tissue and performed regulatory and functional expression studies. RELMbeta mRNA was upregulated in hypoxia in human lung A549 cell line as well as primary cultured adventitial fibroblasts and smooth muscle cells (SMC) of pulmonary arteries. Upon transfection of a RELMbeta encoding expression plasmid into these cells, we observed significant induction of proliferation particularly in SMC and A549 cells, which could be blocked by phosphatidyl-inositol 3-kinase (PI3K) inhibitors LY294002 and wortmannin. The results suggest that human RELMbeta may contribute to hypoxic-induced pulmonary vascular remodeling processes or hypoxia related fibrotic lung disease.

Androstadienes↗

PubMed2006

Antegrade versus retrograde isolated lung perfusion: doxorubicin uptake and distribution in a sarcoma model.

BACKGROUND: Antegrade and retrograde doxorubicin-based isolated lung perfusions were compared in rodents bearing a sarcomatous tumor in the perfused lung. Inasmuch as these tumors derive their vascularization from the bronchial artery system, we hypothesized that retrograde isolated lung perfusion through the pulmonary vein might result in an improved tumor drug uptake. METHODS: Single-pass antegrade (n = 9) and retrograde (n = 9) isolated left lung perfusions were performed with 100 microg of doxorubicin in Fischer rats 10 days after subpleural tumor cell injection. The perfusion, washout, and recirculation times were 20, 10, and 60 minutes, respectively, followed by harvesting of the lung. The doxorubicin concentration and compartmental distribution in the tumor and in normal parenchyma of each perfused lung were measured by high-pressure liquid chromatography (6 animals of each group) and fluorescence microscopy (3 animals of each group). RESULTS: Doxorubicin concentration and pattern of doxorubicin-based fluorescence signaling were comparable for both perfusion techniques in normal lung tissue. Antegrade and retrograde isolated lung perfusion resulted in similar tumor drug uptake, which was lower than in normal lung parenchyma, and in weak and sporadic fluorescence signaling emerging from the tumor periphery and from blood vessels situated within the tumor tissue. CONCLUSIONS: Retrograde isolated lung perfusion did not confer a better doxorubicin uptake in the tumor as compared with antegrade lung perfusion despite the fact that the tumor vascularization in this model is based on the bronchial artery circulation.

Animals↗

PubMed2006

Cytostatic lung perfusion results in heterogeneous spatial regional blood flow and drug distribution: evaluation of different cytostatic lung perfusion techniques in a porcine model.

OBJECTIVES: Comparison of doxorubicin uptake, leakage and spatial regional blood flow, and drug distribution was made for antegrade, retrograde, combined antegrade and retrograde isolated lung perfusion, and pulmonary artery infusion by endovascular inflow occlusion (blood flow occlusion), as opposed to intravenous administration in a porcine model. METHODS: White pigs underwent single-pass lung perfusion with doxorubicin (320 mug/mL), labeled 99mTc-microspheres, and Indian ink. Visual assessment of the ink distribution and perfusion scintigraphy of the perfused lung was performed. 99mTc activity and doxorubicin levels were measured by gamma counting and high-performance liquid chromatography on 15 tissue samples from each perfused lung at predetermined localizations. RESULTS: Overall doxorubicin uptake in the perfused lung was significantly higher (P = .001) and the plasma concentration was significantly lower (P < .0001) after all isolated lung perfusion techniques, compared with intravenous administration, without differences between them. Pulmonary artery infusion (blood flow occlusion) showed an equally high doxorubicin uptake in the perfused lung but a higher systemic leakage than surgical isolated lung perfusion (P < .0001). The geometric coefficients of variation of the doxorubicin lung tissue levels were 175%, 279%, 226%, and 151% for antegrade, retrograde, combined antegrade and retrograde isolated lung perfusion, and pulmonary artery infusion by endovascular inflow occlusion (blood flow occlusion), respectively, compared with 51% for intravenous administration (P = .09). 99mTc activity measurements of the samples paralleled the doxorubicin level measurements, indicating a trend to a more heterogeneous spatial regional blood flow and drug distribution after isolated lung perfusion and blood flow occlusion compared with intravenous administration. CONCLUSIONS: Cytostatic lung perfusion results in a high overall doxorubicin uptake, which is, however, heterogeneously distributed within the perfused lung.

Animals↗

PubMed2006

Sleeve pneumonectomy.

Throughout the last year significant advances in the operative technique and management of patients undergoing sleeve pneumonectomy, as well as better understanding of patient selection requirements, have led to improved perioperative and long-term results. Patients with N2 disease resistant to preoperative chemotherapy or chemo-/radiotherapy should be excluded from the procedure. Airway resection should be limited to a maximum length of 4 cm. In general sleeve pneumonectomy has become an established procedure for treatment of lung cancer involving the carina and should be performed for carefully selected patients in experienced centers only.

Anastomosis, Surgical↗

PubMed2006

Current and future management of chronic thromboembolic pulmonary hypertension: from diagnosis to treatment responses.

Although pulmonary endarterectomy (PEA) has been proven a very effective treatment for chronic thromboembolic pulmonary hypertension, it cannot be performed in a substantial proportion of patients. Here, we outline a proposed treatment algorithm, outlining therapeutic alternatives: (1) PEA should be considered as the first treatment option, where possible; (2) medical intervention is a possible option in inoperable patients and those with significant arteriopathy, although only chronic anticoagulation has been widely used to date (advanced medical treatment options could include prostanoids, endothelin receptor antagonists, or phosphodiesterase-5 inhibitors, but randomized clinical trials are required); (3) pulmonary hypertension is likely to persist after PEA in patients with significant small-vessel arteriopathy, resulting in poor clinical outcome and increased perioperative mortality (medical therapy could also be applied here); (4) anticoagulation therapy and, possibly, advanced medical treatment with careful monitoring may provide benefits in patients with mild or asymptomatic disease; (5) if medical therapy begins to fail, PEA should be offered without delay to avoid progression to severe, secondary arteriopathy; (6) in the absence of severe comorbidity, lung transplantation may be undertaken where PEA has failed, in nonresponders to medical therapy, and in patients with progressive arteriopathy; (7) in patients not eligible for PEA due to collateral and/or surgically inaccessible lesions, balloon angioplasty may be a possible alternative at some centers, but is experimental and requires further assessment. Continued research and clinical trials investigating possible applications of new medical treatments are required.

Algorithms↗

PubMed2006

Techniques and outcomes of pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension.

Cardiopulmonary function in patients with chronic thromboembolic pulmonary hypertension can almost be normalized by pulmonary endarterectomy. The procedure involves the removal of organized and incorporated fibrous obstructive tissue from the pulmonary arteries during circulatory arrest under deep hypothermia. Mortality rates reported for patients who have undergone pulmonary endarterectomy range from 4 to 24%. The operation is not an embolectomy but a true endarterectomy. After proximal intrapericardial pulmonary artery incision, the correct endarterectomy plane is established and circumferentially followed down to the lobar, segmental, and sometimes subsegmental pulmonary artery branches in each lobe. Completion of the endarterectomy procedure in one lung is usually possible within a 15-min period of circulatory arrest. This is followed by reperfusion and another period of circulatory arrest for the endarterectomy on the contralateral side. Additional cardiac procedures can be performed after arteriotomy closure, during the rewarming period, if necessary. The outcomes with regard to functional status, quality of life, hemodynamics, right-ventricular function, and gas exchange are very favorable. After surgery, significant and persistent decreases of pulmonary artery pressures and pulmonary vascular resistance are observed in a large majority of patients. Cardiac output is increased and right-heart function is persistently improved. Postoperative management of patients undergoing pulmonary endarterectomy can be challenging. Important complications are persistent pulmonary arterial hypertension due to inadequate endarterectomy or significant secondary vasculopathy, and reperfusion edema in the endarterectomized parts of the lung. Adequate postoperative care is therefore essential. Preoperative hemodynamic severity and the site of anatomic obstruction are believed to be key predictors of postoperative outcome.

Chronic Disease↗

PubMed2006

Immunosuppressive therapy does not prevent the occurrence of immunoglobulin E-mediated allergies in children and adolescents with organ transplants.

BACKGROUND: Allogeneic organ transplantation has become a common procedure in acute and chronic organ failure. The major limitation, rejection of the allograft by the host's immune system, can be limited by various immunosuppressive drugs that target the adaptive T-cell response. Most of these drugs are used in the treatment of allergic diseases as well, suggesting that transplant recipients under long-term immunosuppressive therapy should not develop any sensitizations or at least not show any clinical signs of allergy. Surprisingly, organ-transplanted children and adults do report symptoms of type 1 allergies, such as allergic rhinoconjunctivitis, bronchial asthma, and food allergies. Thus far, mainly case reports and series on the occurrence of allergy after orthotopic liver transplantation exist. OBJECTIVE: Our purpose with this study was to evaluate in a cross-sectional design the prevalence of immunoglobulin E-mediated sensitizations and type 1 allergies in solid organ-transplanted children and adolescents and to identify risk factors. METHODS: Seventy-eight organ-transplanted subjects (50 kidney, 9 lung, 19 liver; mean age: 14.06 +/- 5.94 years; range 1.42 to 24.25 years) were studied by standardized interviews (modified International Study of Asthma and Allergies in Childhood [ISAAC] criteria), skin-prick tests, and measurement of specific and total serum immunoglobulin E. RESULTS: Nineteen patients (24.4%) were found to be sensitized to > or = 1 common inhalant or food allergens, as reflected by elevated specific immunoglobulin E levels and/or positive skin-prick test results, and 8 subjects (10.3%) additionally reported a corresponding present history of atopic diseases. No severe anaphylactic reactions were reported. No statistically significant associations with gender, kind of transplanted organ, distinct immunosuppressive therapies, and age at time of transplantation or age at investigation were found (chi2 test, Fisher's exact test, and Wilcoxon rank-sum test, respectively). Multiple logistic-regression analysis did not identify any independent risk factor either. CONCLUSION: This study demonstrates that therapeutic immunosuppression does not control sensitizations and clinical manifestation of type 1 allergies in organ-transplanted children and adolescents.

Adolescent↗

PubMed2005

Impact of HIF-1alpha and HIF-2alpha on proliferation and migration of human pulmonary artery fibroblasts in hypoxia.

Proliferation of adventitial fibroblasts of small intrapulmonary arteries (FBPA) has been disclosed as an early event in the development of pulmonary hypertension and cor pulmonale in response to hypoxia. We investigated the role of hypoxia-inducible transcription factors (HIF) in human FBPA exposed to hypoxia. Primary cultures of FBPA displayed a strong mitogenic response to 24 h hypoxia, whereas the rate of apoptosis was significantly suppressed. In addition, the migration of FBPA was strongly increased under hypoxic conditions but not the expression of alpha-smooth muscle actin. Hypoxia induced a marked up-regulation (protein level) of both HIF-1alpha and HIF-2alpha, alongside with nuclear translocation of these transcription factors. Specific inhibition of either HIF-1alpha or HIF-2alpha was achieved by RNA interference technology, as proven by HIF-1alpha and HIF-2alpha mRNA and protein analysis and expression analysis of HIF downstream target genes. With the use of this approach, the hypoxia-induced proliferative response of the FBPA was found to be solely HIF-2alpha dependent, whereas the migratory response was significantly reduced by both HIF-1alpha and HIF-2alpha interference. In conclusion, HIF up-regulation is essential for hypoxic cellular responses in human pulmonary artery adventitial fibroblasts such as proliferation and migration, mimicking the pulmonary hypertensive phenotype in vivo. Differential HIF subtype dependency was noted, with HIF-2alpha playing a predominant role, which may offer future intervention strategies.

Actins↗

PubMed2005

Donor total lung capacity predicts recipient total lung capacity after size-reduced lung transplantation.

BACKGROUND: Size-reduced lung transplantation has only recently undergone widespread use, especially in highly urgent cases. However, it is still not considered standard procedure at most centers. It has the potential to alleviate the donor organ shortage by allowing the use of oversized grafts for small and pediatric recipients. Limited data exist on pre-operative parameters predicting functional outcome after lung transplantation in general, especially after size-reduced lung transplantation. METHODS: All 98 patients undergoing primary lung transplantation during a 2-year period, including 27 size-reduced lung transplantations, were analyzed retrospectively. Pre-operative functional parameters were-after correction of estimated values according to the amount of size reduction-correlated with post-operative functional assessment. Actual and predicted total lung capacity (TLC) of transplant recipients and predicted TLC of donors was compared with the best post-operative TLC achieved within 12 months after transplantation. RESULTS: Size-reduced lung transplantation was performed in 27 cases. Downsizing was achieved by lobar transplantation (n = 9), split-lung transplantation (n = 2) or peripheral segmental resection (n = 16). There was a statistically highly significant (p < 0.01) correlation between donor TLC and best recipient TLC achieved after transplantation (Pearson's correlation coefficient = 0.675). No statistically significant correlation was seen between pre-operative recipient actual TLC and best post-operative TLC (p = 0.87; Pearson's correlation coefficient = 0.415). In standard lung transplant recipients post-operative TLC was correlated with both donor predicted TLC (p < 0.01; Pearson's correlation coefficient = 0.509) and actual pre-operative recipient TLC (p < 0.01; Pearson's correlation coefficient = 0.667). CONCLUSIONS: Post-operative recipient TLC in size-reduced lung transplantation can be predicted by donor TLC rather than pre-operative recipient TLC.

Adolescent↗

PubMed2005

Increased levels and reduced catabolism of asymmetric and symmetric dimethylarginines in pulmonary hypertension.

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS) and has been implicated in endothelial dysfunction. ADMA is metabolized by the enzyme dimethylarginine dimethylaminohydrolase (DDAH), with DDAH2 representing the predominant endothelial DDAH isoform. Symmetric dimethylarginine (SDMA), also originating from arginine methylation by protein arginine methyltransferases, is an inhibitor of intracellular arginine uptake. In both chronic pulmonary hypertensive rats and patients suffering from idiopathic pulmonary arterial hypertension (IPAH; NYHA class III and IV), a marked increase in plasma ADMA and SDMA levels, as well as tissue levels of asymmetric and symmetric dimethylated proteins, was observed. Moreover, when comparing lung tissue from pulmonary hypertensive rats and IPAH patients to corresponding normal lung tissue, expression of DDAH2 was found to be reduced at both the mRNA and the protein level with no significant changes in DDAH1 expression. These findings were further supported by demonstrating a decrease in DDAH2 function in the experimental pulmonary hypertension model. Immunohistochemistry in human and rat control tissue demonstrated both isoforms of DDAH in the endothelial layer and in the alveolar epithelium. In contrast, in pulmonary hypertensive tissue, the immunoreactivity of DDAH2 in pulmonary endothelium was significantly decreased compared with DDAH1. Therefore, altogether we can conclude that enhanced dimethylarginine levels may contribute to vascular abnormalities in pulmonary arterial hypertension. Suppression of endothelial DDAH2 expression and function represents an important underlying mechanism.

Amidohydrolases↗

PubMed2005

Hypoxia-driven proliferation of human pulmonary artery fibroblasts: cross-talk between HIF-1alpha and an autocrine angiotensin system.

Pulmonary artery adventitial fibroblasts (FBPA) may play a central role in lung vascular remodeling under conditions of hypoxia and inflammation, the result being pulmonary hypertension and cor pulmonale. In cultured human FBPA, both angiotensin II (Ang II) and hypoxia promoted cell cycle progression and cell proliferation and suppressed apoptosis. These effects were further enhanced when both stimuli were applied simultaneously. Hypoxia elevated the expression of hypoxia-inducible factor 1alpha (HIF-1alpha) and increased the expression of genes regulated by the hypoxia-responsive element (HRE). Up-regulation of both angiotensin-converting enzyme (ACE) and Ang II receptor type 1 (AT1) was also observed. Exogenous Ang II further increased HIF/HRE-dependent signaling in FBPA, whereas suppression of the autocrine ACE-Ang II-AT1 loop with inhibitors of ACE, AT1, and phosphatidylinositol 3-kinase (PI3K) reduced the proliferative response to both hypoxia and exogenous Ang II. Overexpression of HIF-1alpha by transient transfection caused the same proliferative effect and up-regulation of AT1 expression that were observed under hypoxic conditions. In contrast, small interfering RNA targeting HIF-1alpha inhibited hypoxia-induced ACE and AT1 expression. Our studies indicate that the ACE-Ang II-AT1 system serves as a positive feedback loop and fosters FBPA proliferation under hypoxic conditions, with the PI3K-HIF-HRE axis as the central effector pathway. This pathway may thus facilitate vascular remodeling under hypoxic conditions.

Angiotensin II↗

PubMed2005

Initial experience with oral valganciclovir for pre-emptive cytomegalovirus therapy after lung transplantation.

BACKGROUND: The most common opportunistic viral pathogen after lung transplantation is cytomegalovirus (CMV). Oral valganciclovir, a prodrug of ganciclovir, has been introduced as a potential drug for prophylaxis and treatment of CMV infection and disease in lung transplantation. The goal of this study was to describe our initial experience with oral valganciclovir for pre-emptive treatment of CMV infections after lung transplantation. METHODS AND PATIENTS: We summarize our experience with 19 patients who underwent lung transplantation and received pre-emptive oral valganciclovir therapy in the situation of positive CMV polymerase chain reaction (PCR) in either plasma or bronchoalveolar lavage. None of the patients presented with manifest CMV disease. Treatment dosage of valganciclovir was 450 mg to 1800 mg daily, depending on renal function and white blood count. Treatment was continued until the CMV PCR became negative, in any case for a period of at least 14 days. RESULTS: Three patients received two courses of pre-emptive oral valganciclovir; 16 patients were treated once. Eleven patients (57.9%) were treated because of a positive plasma CMV PCR; in eight patients (42.1%) the PCR was positive only in bronchoalveolar lavage. Therapy was initiated 896 +/- 1186 days (range, 108-3911) after transplantation with a mean CMV PCR of 45,536 +/- 149,294 copies (range, 426-706,000). In all cases the PCR fell below detectability (<400 copies) after a period of 22 +/- 10 days of treatment (range, 7-50 days). Mild to moderate leucopenia was observed in seven patients (36.8%) during treatment. None of the patients developed new onset of other potentially drug-related disorders such as neutropenia, anemia, deterioration of renal function or gastrointestinal disorder. CONCLUSIONS: Pre-emptive therapy with oral valganciclovir for CMV infections detected by PCR in either plasma or bronchoalveolar lavage after lung transplantation seems to be efficacious and safe. However, regular blood counts should be performed to detect developing leucopenia.

Administration, Oral↗

PubMed2005

Bronchial stump coverage with a pedicled pericardial flap: an effective method for prevention of postpneumonectomy bronchopleural fistula.

BACKGROUND: Bronchopleural fistula is a serious complication after pneumonectomy. The aim of this retrospective study was to investigate the efficacy of bronchial stump reinforcement with a pedicled flap of whole pericardium. METHODS: The bronchial stump of 93 consecutive patients who underwent pneumonectomy between July 1988 and March 2003 was covered with a pedicled pericardial flap. Pneumonectomy was performed for primary lung cancer in 89.2% of patients. The study patients received concomitant extensive mediastinal lymphadenectomy, resection of adjacent structures (aorta, vena cava, thoracic wall), and neoadjuvant or planned adjuvant chemotherapy or radiotherapy, or both. Operative and perioperative complications were recorded, and patients were followed up for a mean of 15 +/- 21.2 months (range, 9 to 126). RESULTS: Perioperative mortality was 4.3% (n = 4; pulmonary embolism, sepsis, cardiac arrest, and sudden death in 1 patient each). Perioperative complications occurred in 2 patients: renal failure and hemiplegia in 1 patient and cardiac tamponade in 1 patient. The latter complication, caused by tight reconstruction of the pericardium, was directly related to the applied method and required reoperation. No evidence of postpneumonectomy bronchopleural fistula was observed perioperatively and during the whole follow-up. One-year and 2-year survival was 65.7% and 44.8%, respectively. CONCLUSIONS: Bronchial stump reinforcement with a pericardial flap is a highly effective method for preventing postpneumonectomy bronchopleural fistula in selected patients.

Aged↗