Symptomatic pulmonary allograft Kaposi's sarcoma in two lung transplant recipients.

Kaposi's sarcoma (KS) is associated with solid-organ transplantation, but is extremely rare after lung transplantation. In this report, we describe two unique cases of lung transplant recipients who developed KS in the lung allograft and were treated with sirolimus and liposomal doxorubicin. One patient survived 12 months after the diagnosis of KS; the other survived 3 months after diagnosis and was found to have concomitant EBV-negative, HHV-8-positive B-cell lymphoma. We demonstrate a partial response of pulmonary KS to reduced immunosuppression and the initiation of sirolimus in one patient, as well as an association between increasing HHV-8 viremia and progression of pulmonary KS. Our report highlights the importance of secondary malignancies in patients with transplant-related KS and supports the association between HHV-8 infection and EBV-negative PTLD.

Alemtuzumab in the treatment of refractory acute rejection and bronchiolitis obliterans syndrome after human lung transplantation.

Despite substantial improvements in early survival after lung transplantation, refractory acute rejection (RAR) and bronchiolitis obliterans syndrome (BOS) remain major contributors to transplant-related morbidity and mortality. We have utilized alemtuzumab, a humanized anti-CD52 antibody which results in potent lymphocyte depletion, in consecutive patients with RAR (n = 12) or BOS (n = 10). All patients failed conventional treatment with methylprednisolone and antithymocyte globulin and received strict infection prophylaxis. Alemtuzumab significantly improved histological rejection scores in RAR. Total rejection grade/biopsy was 1.98 +/- 0.25 preceding alemtuzumab versus 0.33 +/- 0.14 posttreatment, p-value <0.0001 (with a similar number of biopsies/patient per respective time interval). Freedom from BOS was observed in 65% of RAR patients 2 years after alemtuzumab treatment. Although there was no statistically significant change in forced expiratory volume in 1 second (FEV1) before and after alemtuzumab treatment in patients with BOS, a stabilization or improvement in BOS grade occurred in 70% of patients. Patient survival 2 years after alemtuzumab for BOS was 69%. Despite a dramatic decline in CD4 counts in alemtuzumab-treated patients, only one patient developed a lethal infection. Thus, we provide the first evidence that alemtuzumab is a potentially useful therapy in lung transplant recipients with RAR or BOS.

Impact of lung transplant operation on bronchiolitis obliterans syndrome in patients with chronic obstructive pulmonary disease.

Previous studies suggest that bilateral (BLT) compared with single lung transplantation (SLT) for patients with chronic obstructive pulmonary disease (COPD) results in improved long-term survival. The effect of transplant operation on bronchiolitis obliterans syndrome (BOS) is unknown. A retrospective study of all lung transplant recipients with pre-transplant diagnoses of COPD at the University of Toronto and at Duke University was performed. Data collected were age, gender, date and type of transplant, acute rejection, survival, presence and time of BOS. 221 (bilateral n = 101, single n = 120) patients met our criteria. Patients with BLT were younger (53.0 vs. 55.3 years; p = 0.034), more likely to be male (56.3% vs. 42.4%; p = 0.039) and more likely to be transplanted at the University of Toronto (79.6% vs. 16.1%; p < 0.001). Freedom from BOS was similar at 1 year post-transplant. However, BLT recipients were more commonly free from BOS 3 years (57.4% vs. 50.7%) and 5 years (44.5% vs. 17.9%) post-transplant (p = 0.024). Survival of BLT was better than SLT recipients at 3 and 5 years post-transplant (BLT vs. SLT: 67.5% vs. 61.1% and 60.7% vs. 34.1%, respectively; p = 0.018). Similar trends on survival were observed after development of BOS. BLT results in lower rates of BOS in patients with COPD that are eligible for both SLT and BLT.

Ontogeny and localization of TGF-beta type I receptor expression during lung development.

Transforming growth factor (TGF)-beta is a family of multifunctional cytokines controlling cell growth, differentiation, and extracellular matrix deposition in the lung. The biological effects of TGF-beta are mediated by type I (TbetaR-I) and II (TbetaR-II) receptors. Our previous studies show that the expression of TbetaR-II is highly regulated in a spatial and temporal fashion during lung development. In the present studies, we investigated the temporal-spatial pattern and cellular expression of TbetaR-I during lung development. The expression level of TbetaR-I mRNA in rat lung at different embryonic and postnatal stages was analyzed by Northern blotting. TbetaR-I mRNA was expressed in fetal rat lungs in early development and then decreased as development proceeded. The localization of TbetaR-I in fetal and postnatal rat lung tissues was investigated by using in situ hybridization performed with an antisense RNA probe. TbetaR-I mRNA was present in the mesenchyme and epithelium of gestational day 14 rat lungs. An intense TbetaR-I signal was observed in the epithelial lining of the developing bronchi. In gestational day 16 lungs, the expression of TbetaR-I mRNA was increased in the mesenchymal tissue. The epithelium in both the distal and proximal bronchioles showed a similar level of TbetaR-I expression. In postnatal lungs, TbetaR-I mRNA was detected in parenchymal tissues and blood vessels. We further studied the expression of TbetaR-I in cultured rat lung cells. TbetaR-I was expressed by cultured rat lung fibroblasts, microvascular endothelial cells, and alveolar epithelial cells. These studies demonstrate a differential regulation and localization of TbetaR-I that is different from that of TbetaR-II during lung development. TbetaR-I, TbetaR-II, and TGF-beta isoforms exhibit distinct but overlapping patterns of expression during lung development. This implies a distinct role for TbetaR-I in mediating TGF-beta signal transduction during lung development.

Tracheobronchial amyloidosis. The Boston University experience from 1984 to 1999.

Tracheobronchial amyloidosis (TBA), an idiopathic disorder characterized by deposition of fibrillar proteins in the tracheobronchial tree, occurred in 10 patients referred to the Amyloid Program at Boston University over the past 15 years. Fewer than 100 cases of TBA have been described; only 1 series encompassed more than 3 patients. We analyzed our experience with biopsy-proven TBA to define better its natural history. Follow-up averaged approximately 8 years and was obtained in all cases, making this outcome reporting the largest and most complete to date. Three of these patients were prospectively studied for up to 24 months to examine the utility of bronchoscopy, computerized tomography (CT) imaging, and pulmonary function tests (PFTs) in monitoring disease progression. No patient with TBA developed signs or symptoms of systemic amyloidosis during the period reviewed. Conversely, tracheobronchial disease was not diagnosed in 685 patients with primary systemic (AL) amyloidosis during the 15-year study period at Boston University. Bronchoscopy proved most useful in establishing the diagnosis by biopsy. Narrowing of major airways limited its inspection of the tracheobronchial tree, however. In contrast, CT imaging provided quantitative assessment of airway narrowing and mural thickening--2 major consequences of amyloid infiltration. These CT features, in the presence of mural calcifications sparing the posterior tracheal membrane, have been reported in few disorders other than TBA. The ability of CT to map airway involvement and identify extraluminal manifestations of TBA made it the study of choice for establishing disease extent. Three patterns of disease were evident by CT imaging and bronchoscopic examination: proximal, mid, and distal airways involvement. Those with severe proximal disease had significantly decreased air flows, air trapping, and fixed upper airway obstruction on PFTs. Patients with distal disease had normal airflows. PFTs could not clearly distinguish proximal from severe mid airways disease. Thirty percent of patients died within 7-12 years after diagnosis, all having proximal or severe mid airways disease. Repeated rigid bronchoscopic debridement and laser treatments did not prevent progressive airways narrowing in patients dying from TBA. Most patients with mid airways involvement, and all distal airway cases, had either stagnant disease or slowly increasing amyloid deposits when followed for up to 14 years. In a small subset of patients followed prospectively, serial PFTs were most sensitive to disease progression. CT-derived measures of airway lumen diameter and wall thickness did not change significantly despite marked improvements in airflow after rigid bronchoscopy. Our experience suggests that serial PFTs and CT imaging together offer the best assessment of airway involvement and disease progression in patients with TBA. In the future, radiation therapy may provide more definitive treatment of TBA than debulking procedure have to date.

Phagocyte-generated superoxide reduces Fe3+ to displace it from the surface of asbestos.

Injury after exposure to mineral oxide dusts is considered to be mediated by free radical generation. In vitro production of hydroxyl radical by a fibrous silicate increases with the [Fe3+] complexed to the dust surface. The study hypothesis tested was that extracellular fluids and phagocytic cells can decrease concentrations of iron complexed to the surface of a fibrous silicate by employing host chelators and reductants. Such a depletion of surface [Fe3+] would predict decrements in both oxidant generation and the resultant injury after inhalation and instillation of these mineral oxides. Crocidolite (2.0 mg) which was exposed to either 5.0 ml rat plasma or 10.0 ml rat lavage fluid for 1 h had diminished surface [Fe3+]. Similarly, incubations of crocidolite (2.0 mg) with either 10.0 ml rat alveolar macrophages (1.0 x 10(6) cells/ml) or 10.0 ml rat neutrophils (1.0 x 10(7) cells/ml) decreased concentrations of surface iron. In vivo exposures of asbestos contained in chambers allowing or precluding inflammatory cell entry revealed that the influx of phagocytes was associated with greater decreases in surface [Fe3+]. The body chelators transferrin and lactoferrin were unable to extract the metal from fiber surface in vitro. However, superoxide generated by phagocytes did displace the iron from the crocidolite surface. We conclude that extracellular fluids and phagocytic cells have a capacity to diminish [Fe3+] complexed to the surface of asbestos and therefore decrease the potential for oxidative stress and injury to a living system after exposure to these dusts.(ABSTRACT TRUNCATED AT 250 WORDS)

Type I collagen formation in rat type II alveolar cells immortalised by viral gene products.

BACKGROUND: Alveolar type II (T2) cells synthesise matrix proteins such as type IV collagen and fibronectin. In contrast, a fetal rat T2 cell line has been shown to synthesise type I and III collagen as well as type IV collagen. To study regulation of collagen production in T2 cells, neonatal T2 cells immortalised by adenoviral 12SE1A gene transfer were used. It was previously reported that this immortalised cell line (E1A-T2) retains epithelial features such as tight junctions and cytokeratins but also expresses mesenchymal features such as vimentin. METHODS: Collagen production was examined in E1A-T2 and primary neonatal T2 cells using polyacrylamide gel electrophoresis. Electron microscopy was used to examine collagen deposition in E1A-T2 cell culture. To define the mechanism by which alpha 1(I) type I collagen gene expression was activated in E1A-T2 cells, a deletional analysis of alpha 1(I) promoter constructs linked to the bacterial chloramphenicol acetyltransferase gene was performed. RESULTS: E1A-T2 cells produced large amounts of type I collagen with a predominance of alpha 1(I) homotrimers; alpha 2(I) peptides were detected only in the cell layer. In contrast, primary neonatal rat T2 cell cultures produced a trace amount of type I collagen. Production of alpha 1(I) peptide chains (per microgram DNA) in E1A-T2 cell cultures was 30 times higher than that observed in primary neonatal T2 cell cultures. Electron microscopy showed deposition of type I collagen fibrils in the extracellular matrix of E1A-T2 cell cultures. Transfection studies suggested at least two cis-acting elements which mediate increased alpha 1(I) gene expression in E1A-T2 cells. CONCLUSIONS: These studies indicate that the E1A-T2 cell line may be useful for studying type I collagen gene regulation in alveolar T2 cells. These findings also raise the possibility that viral activation of type I collagen genes in alveolar epithelium may be involved in certain forms of pulmonary fibrosis.

A rat alveolar type II cell line developed by adenovirus 12SE1A gene transfer.

The regulation of pulmonary alveolar type II cell proliferation and differentiation is poorly understood and has been difficult to study, in part due to lack of proliferation, cellular heterogeneity, and phenotypic instability of type II cells in primary culture. To develop a stable population of homogeneous cells capable of proliferation, we transfected type II cells isolated from the lungs of neonatal rats with an immortalizing oncogene, adenovirus 12SE1A, using a retroviral vector. Individual clones were isolated, screened for cytokeratin expression, and further characterized. One of the 12SE1A expressing clones, E1A-T2, has epithelial features such as cytokeratin expression and tight junctions, and coexpresses vimentin. E1A-T2 rapidly proliferate when grown in 10% fetal bovine serum, and slow their growth at confluence. A labeling index of greater than 90% during a 24-h pulse of [3H]thymidine reflects a uniform population of proliferating cells. E1A-T2 can be grown and passed in 0.4% fetal bovine serum, suggesting the production of an autocrine growth factor(s). The type II cell Maclura pomifera agglutinin (MPA)-binding glycoprotein, MPA-gp200, appears to be expressed in an incompletely glycosylated form, whereas other features of differentiated type II cells, such as lamellar bodies, surfactant protein A, and a high percentage of saturated phosphatidylcholine, are absent. Homogeneous, clonally derived type II cell lines, such as E1A-T2 may retain sufficient type II cell features of interest to test new hypotheses relating to cell proliferation and differentiation otherwise not feasible using primary cultures of type II cells.

SV40T-immortalized lung alveolar epithelial cells display post-transcriptional regulation of proliferation-related genes.

To study the regulation of proliferation of lung alveolar epithelial type 2 cells, we have established a cell line derived from neonatal type 2 cells by transfection with the SV40 large T antigen gene. We find that this cell line, designated SV40-T2, displays the same post-transcriptional control of expression of proliferation-related genes, including c-myc, ornithine decarboxylase, thymidine kinase, and histone, that we have previously described in primary isolates of type 2 cells (Clement et al., Proc. Natl. Acad. Sci. USA 87, 318-322, 1990). Both proliferating and nonproliferating SV40-T2 cells express these genes at high levels, but their translation products are only detected in proliferating cells. Using the histone gene as an example, we have found that regulation of expression occurs at the level of transcription and of mRNA turnover, as previously described in other mammalian systems. However, in addition, regulation of expression also occurs at the level of translation of the histone mRNA, because its protein product is not detectable in nonproliferating SV40-T2 cells. We have analyzed the steps which are potentially involved in this translational regulation of histone gene expression in SV40-T2 cells. In both proliferating and nonproliferating cells, histone mRNA was found to be efficiently transported from the nucleus to the cytoplasm and to associate with the translationally active heavy polysomal fractions. These results indicate that control of histone gene expression (and perhaps that of other proliferation-related genes) in lung epithelial cells may involve either rapid and selective degradation of histone protein or binding factor(s) which modulate translational efficiency of histone mRNA.

Mechanisms of mastoparan-stimulated surfactant secretion from isolated pulmonary alveolar type 2 cells.

Mastoparan, a tetradecapeptide component of wasp venom, is a potent activator of secretion in a variety of cell types, and has been shown to activate purified G-proteins reconstituted into phospholipid vesicles with a preferential activation of Gi over Gs (Higashijima, T., Uzu, S., Nakajima, T., and Ross, E. R. (1988) J. Biol. Chem. 263, 6491-6494). To identify the biochemical activities of mastoparan in a cellular system, we characterized the effects of mastoparan on signal transduction pathways in rat pulmonary alveolar type 2 epithelial cells, which synthesize and secrete pulmonary surfactant. Mastoparan inhibited adenylylcyclase activity in a manner that was dose-dependent (IC50 = 30 microM), but sensitive to neither guanine nucleotide nor pertussis toxin (PT). Mastoparan induced a PT-sensitive increase in cellular inositol trisphosphate and a rapid rise in cytosolic calcium released from intracellular stores; the time to onset of the calcium rise, but neither the rate nor the amplitude of the rise, were PT-sensitive. Mastoparan also caused a dose- (EC50 = 16 microM) and time-dependent activation of arachidonic acid release that was completely insensitive to pretreatment with PT. Secretion of pulmonary surfactant was increased by mastoparan approximately 8-fold over constitutive levels at 1 h with an EC50 = 20 microM, and mastoparan-stimulated secretion was partially sensitive to PT at late time points and to inhibitors of arachidonic acid metabolism, but not to the protein kinase C inhibitor H7. These findings are consistent with the activation of Gi proteins in type 2 cells by mastoparan, although the lack of predicted triphosphoguanine nucleotide and PT sensitivity for some activities indicates that mastoparan does not act in a manner strictly analogous to liganded receptors or that some activities are not mediated by activation of Gi. While mastoparan is a potent secretagogue in several cell types, its secretory activity appears to have only a limited dependence on the activation of Gi proteins in type 2 cells.