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No-cut thoracoscopic lung plication: a new technique for lung volume reduction surgery.

BACKGROUND: Lung volume reduction surgery (LVRS) using a linear cutting stapler or laser ablation via median sternotomy or thoracoscopy is a current therapy for symptomatic emphysema. The primary causes of morbidity and mortality (as high as 20%) are existing comorbidities and prolonged air leaks secondary to visceral pleural division. We report a novel technique using minimally invasive techniques designed to achieve volume reduction while preserving the visceral pleura. A novel lung grasper and a knifeless stapler are used to permanently plicate lung tissue without cutting visceral pleura. STUDY DESIGN: This prospective analysis involves a consecutive series of patients who had LVRS using this method. Between May 1995 and September 1996, 32 patients underwent 50 unilateral, staged bilateral, or bilateral thoracoscopic lung plication procedures. The indications for LVRS were standard; they included severe limiting dyspnea (forced expiratory volume in one second [FEV1] = 0.68 +/- 0.05), hyperinflated lungs with flattened diaphragms on chest x-ray, and diffuse emphysema seen on chest computed tomography scan. Ventilation and perfusion scanning was used to identify potential ventilation and perfusion mismatch target areas of lung for plication. RESULTS: The right lung was plicated first in 25 of 32 patients (78%), and upper lobe plications predominated (77%). A mean of 9.3 +/- 0.8 staple firings were used for each unilateral plication procedure. There were no perioperative deaths. Two patients (4%) required axillary thoracotomies to repair air leaks. Mean chest tube duration was 6.3 +/- 0.5 days. Median hospital stay was 7 days (range 3-15). An Intensive Care Unit stay was required following 8 procedures (17%). Postoperative morbidity occurred in 18 (39%) of 46 procedures, including 5 cases of atrial fibrillation and 4 persistent (> 7 days) air leaks. A minimum 2 month followup was available for 22 patients (32 of 46 procedures), demonstrating a clear chest x-ray with significant improvement in ipsilateral diaphragmatic contour. Twelve patients had unilateral reduction, and 10 patients had bilateral reduction in either a staged (n = 7) or sequential at one operation (n = 3) fashion. Twenty-five (78%) of 32 procedures were associated with improved pulmonary function, with a mean increase in FEV1, in patients in this subgroup of procedures, of 43 +/- 7% for each ipsilateral plication at a mean followup of 3.8 +/- 0.5 months. For the entire group of 32 procedures, the mean improvement in measured FEV1 was 29 +/- 7%. Supplemental oxygen requirement was significantly reduced in 9 of 16 patients following plication. CONCLUSION: These data suggest that minimally invasive surgical techniques coupled with a no-cut lung plication can achieve significant lung volume reduction with favorable postoperative morbidity and mortality. Lung plication appears to hold promise as an alternative technique of LVRS.

Humans↗

Does hyperexpansion of the native lung adversely affect outcome after single lung transplantation for emphysema? Preliminary findings.

RATIONALE AND OBJECTIVES: The authors evaluated the effect of the native emphysematous lung on graft function after single lung transplantation. MATERIALS AND METHODS: Thirty-two patients who underwent single lung transplantation were examined with radiography preoperatively for degree of emphysema and postoperatively for hyperexpansion of the native lung. All patients underwent ventilation-perfusion scanning before transplantation and ventilation scanning after transplantation. Pulmonary function tests and measurement of arterial partial pressure of oxygen were also measured before and after surgery. The postoperative course was graded on a subjective scale. RESULTS: Hyperexpansion of the native lung was seen in 16 of the 32 patients in the postoperative period. On the basis of serial measurements of forced expiratory volume in 1 minute, these patients fared poorly in the postoperative period compared with patients without hyperexpansion. Pulmonary blood flow to the native lung, as measured with perfusion scintigraphy, paradoxically increased in 11 patients after transplantation. Nine of these 11 patients demonstrated hyperinflation of the native lung, suggesting that graft compression adversely affects blood flow to the transplanted lung. CONCLUSION: Hyperexpansion of the native lung after single lung transplantation for emphysema may have a deleterious effect on graft function and possibly on clinical outcome.

Female↗

Lung endothelial dipeptidyl peptidase IV is an adhesion molecule for lung-metastatic rat breast and prostate carcinoma cells.

Attachment of circulating tumor cells to endothelial cell adhesion molecules restricted to select vascular compartments is thought to be responsible for site-specific metastasis. Lung-metastatic rat R3230AC-MET breast and RPC-2 prostate carcinoma cells bound outside-out endothelial cell membrane vesicles, prepared by perfusion of the rat lung vasculature with a low-strength formaldehyde solution, in significantly higher numbers than their nonmetastatic counterparts R3230AC-LR and RPC-LR. In contrast, vesicles derived from the vasculature of a nonmetastasized organ (e.g., hind leg muscle) showed no binding preference for either of the four tumor cell lines. Lung-derived endothelial vesicles were used here to generate mAbs against lung endothelial cell adhesion molecules. The first group of mice were actively immunized against lung endothelial vesicles, whereas the second group was injected with syngeneic mouse antiserum against leg endothelial vesicles before active immunization with lung endothelial vesicles. 17 hybridoma supernatants obtained from the two fusions bound lung vesicles with at least a 10-fold higher affinity than leg vesicles. Seven (four obtained by a passive/active immunization protocol) stained rat capillary endothelia. One mAb, mAb 8.6A3, inhibited specific adhesion of lung-derived vesicles to lung-metastatic breast and prostate carcinoma cells. Purification of the antigen (endothelial cell adhesion molecule) from rat lung extracts revealed a protein with a 110-kD mol wt. NH2-terminal sequencing established identity with dipeptidyl peptidase IV which had been reported to serve as a fibronectin-binding protein. These results indicate that vesicles obtained from in situ perfused organs are a convenient immunogen for the production of antibodies to compartment-specific endothelial cell surface molecules, and reinforce the concept that endothelial cell surface components are selectively recognized by circulating cancer cells during metastasis formation.

Animals↗

Lung lavage with oxygenated perfluorochemical liquid in acute lung injury.

OBJECTIVE: To investigate the effects of lung lavage with oxygenated liquid perfluorochemical on gas exchange, lung mechanics, and cardiac function in animals with acute lung injury. DESIGN: Prospective, randomized, controlled trial. SETTING: Animal laboratory. SUBJECTS: Eight adult cats (2 to 4 kg, random sex). INTERVENTIONS: Two insults were combined to cause lung injury: oleic acid infusion and saline whole-lung wash. Animals were assigned to either the control or treatment group which consisted of a perfluorochemical liquid (Rimar 101) lavage. Perfluorochemical liquid lavage was performed three times at hourly intervals after lung injury. Three other cats with identical injury but no perfluorochemical liquid lavage served as control animals. All cats were ventilated with an FIO2 of 0.95 and positive end-expiratory pressure of 2 cm H2O continuously. MEASUREMENTS AND MAIN RESULTS: Arterial blood gas tensions and pH, dynamic pulmonary compliance were measured at 15-min intervals. Cardiac index was assessed hourly, and lung fluid was collected after each of the three perfluorochemical liquid lavages. Arterial oxygen tension and pulmonary compliance deteriorated abruptly after lung injury in all cats, and improved significantly (p < .001, two-way analysis of variance) 15 mins after perfluorochemical liquid lavage. These parameters gradually returned to their baseline over 60 mins. Arterial blood pressure and cardiac index decreased after injury in all cats, and were not significantly changed after perfluorochemical liquid lavage. Hemorrhagic fluid was recovered from distal airways by perfluorochemical liquid lavage, despite prior suctioning of the airway. CONCLUSIONS: Perfluorochemical liquid lavage removes pulmonary edema fluid and improves gas exchange and the mechanical properties of the lung, after acute severe lung injury.

Animals↗

Effect of lung water content, manipulated by intratracheal furosemide, surfactant, or a mixture of both, on compliance and viscoelastic tissue forces in lung-lavaged newborn piglets.

OBJECTIVE: To study the impact of lung water content and its reduction by a topically applied diuretic on respiratory and lung tissue mechanics in comparison with surfactant administration in surfactant-deficient newborn piglets with lavage-induced lung injury. DESIGN: Controlled, randomized study. SETTING: Animal research facility. SUBJECTS: Newborn piglets. TREATMENT Piglets were surfactant depleted by lung lavage and, after a pretreatment period, randomly treated with intratracheal furosemide, furosemide and surfactant, or with surfactant alone. MEASUREMENTS AND MAIN RESULTS: Dynamic compliance (C(DYN)), static compliance (C(ST)), stress-adaptation pressures (P(DIFF)) and post mortem lung water content were determined. Static compliance in the furosemide-surfactant group was not significantly higher than in the surfactant group. At the end of the study, C(ST) did not differ between the three groups because C(ST) in the furosemide group had increased to values similar to those of the surfactant-containing treatment groups: C(ST) F+S: 0.73 +/- 0.2 mL/cm H2O/kg body weight (BW); C(ST) S: 0.61 +/- 0.11 mL/cm H2O/kg BW; and C(ST) F: 0.60 +/- 0.19 mL/cm H2O/kg BW). Compliance was inversely and P(DIFF) was directly correlated to lung water (LW) content (C(ST) vs. LW: r2 = .59, p = .001; C(DYN) vs. LW: r2 = .49, p = .006; P(DIFF) vs. LW: r2 = .37, p = .059), independent of the type of treatment. Changes in C(ST) and C(DYN) were inversely related to changes in P(DIFF). Intrapulmonary furosemide was more rapidly absorbed when administered to the surfactant-depleted lung alone compared with the mixture with surfactant, and intrapulmonary furosemide had a rapid systemic effect. CONCLUSION: Although the combination of surfactant with a diuretic failed to increase respiratory compliance to a significantly larger extent than surfactant alone, furosemide at the end of the study increased respiratory compliance to a level similar to surfactant-containing treatments. Lung water content and, to a lesser extent, the absence or presence of surfactant appeared to determine lung mechanics, and its impact on lung mechanics was similar to surfactant administration.

Animals↗

Technetium-fibrinogen lung scanning in canine lung contusion.

To detect experimentally induced acute lung contusion in anesthetized dogs, serial radionuclide images of the lung were recorded following intravenous infusion of 99mTc-labelled human fibrinogen (Tc-HF). The accumulation of Tc-HF in canine lungs was serially quantitated for up to 20 hours after lung contusion. A contusion (#1) was produced in one lung, Tc-HF was injected IV after 15 minutes, and 75 minutes later a contralateral lung contusion (#2) was produced in a series of 14 dogs. At autopsy the excised lungs were scanned, sectioned, and counted for radioactivity. Radiolabelled fibrinogen accumulated within 2-4 minutes of contusion #2 and remained stable over the next 20 hours in 14 dogs; contusion #1 was barely visible in four dogs. Lung Tc-HF activity in the central region of contusion #2 remained sixfold higher than in normal lung tissue. These data suggest that following lung contusion, fibrinogen deposition occurs rapidly and remains stable over a 20-hour interval of observation.

Animals↗

Similarity of pulmonary rejection patterns among heart-lung and double-lung transplant recipients.

The transbronchial biopsy and clinical courses of 9 double-lung and 1 single-lung recipients surviving greater than 10 days were analyzed and compared to those of 15 heart-lung transplants performed during the same time period. Of these, 8 isolated lung (LT) and 11 heart-lung transplant (HLT) recipients survived greater than 50 days and were at risk of developing obliterative bronchiolitis believed to be a form of chronic rejection. Cyclosporine-based immunosuppression, in combination with azathioprine and steroids, was used for 22 of 25 patients. Two double-lung recipients and 1 heart-lung patient received FK506 as the sole immunosuppressive agent; 90% and 62% of LT, and 67% and 54% of HLT recipients developed acute and chronic rejection, respectively (P = NS). The average time to first episode of acute (30.2 days [LT] versus 21.5 days [HLT]) and chronic rejection (146 days [LT] versus 193.7 days [HLT]) was not different between groups (P = NS). Age (34.2 [LT] versus 29.1 [HLT]) and sex (M:F, 5:5 [LT] versus 5:10 [HLT]) were also not found to be discriminators. The histologic diagnosis of chronic rejection was associated with significant declines in FEV1.0 and FEF25-75 (P less than 0.02). There was only one instance of cardiac rejection among the heart-lung transplant recipients. Heart-lung and isolated lung transplant patients appear to be at similar risk for developing acute or chronic pulmonary rejection.

Adult↗

A novel model of selective lung ventilation to investigate the long-term effects of ventilation-induced lung injury.

Mechanical ventilation (MV) with large tidal volumes (V(T)) causes ventilator induced lung injury. Whereas immediate effects of short-term injurious ventilation are well studied, little is known about its long-term effects. We aimed to establish an animal model of selective injurious MV, permitting assessment of the long-term course of ventilation-induced lung injury. In anesthetized and instrumented rats (n = 26), laryngoscopy was performed, and one cannula for MV was placed in the left main bronchus and a second one in the trachea. Two ventilators were used to ventilate the left lung with high (20 mL/kg) and the right lung with low (4 mL/kg) V(T). In control animals, both lungs received low V(T). After 2 h of MV, animals were extubated and observed for 24 h and then killed. Left and right lungs were excised and sampled for further investigations. Survival in animals ventilated with the high V(T) was 90%. Twenty-four hours after MV, alveolar levels of humoral (tumor necrosis factor alpha, interleukin 6) and cellular (polymorphonuclear leukocytes) inflammatory markers were increased, and histological alterations were present in lungs ventilated with high V(T). A delayed decrease in PaO2 was noted 24 h after MV, with high V(T) delivered to one lung as compared with low V(T) delivered to both lungs. This animal model permits assessment of the long-term course of ventilation-induced lung injury and shows that pulmonary inflammation and histological alterations are present 24 h after unilateral injurious ventilation.

Animals↗

Efficacy of video assisted thoracoscopic lung biopsy: an historical comparison with open lung biopsy.

BACKGROUND: Video assisted thoracoscopic lung biopsies were compared with historical controls undergoing open lung biopsy to determine the diagnostic accuracy, effect on length of postoperative stay, and cost effectiveness of the new thoracoscopic technique. METHODS: The first 25 video assisted thoracoscopic lung biopsies performed in the Edinburgh Thoracic Unit were compared with 25 historical controls for complications, diagnostic accuracy, and length of postoperative stay. RESULTS: Statistical comparison showed equal diagnostic accuracy in both groups (96% v 92%), but mean (SD) inpatient stay was reduced in the video assisted thoracoscopic group (1.4 (0.7) days) compared with those undergoing open lung biopsy (3.1 (1.8) days). No postoperative complications were reported in the group which underwent video assisted thoracoscopic lung biopsies but three patients had postoperative complications in the open lung biopsy group. CONCLUSIONS: Video assisted thoracoscopic lung biopsy is as effective in providing histological diagnosis as is open lung biopsy. All postoperative complications were related to post thoracotomy pain and occurred only in patients undergoing open lung biopsy. Reduced postoperative disability in the video assisted thoracoscopic group decreased hospital stay, offsetting the increased cost in disposables. The overall cost of video assisted thoracoscopic and open lung biopsy was 712 pounds and 1114 pounds, respectively.

Adult↗

Evaluation of lung injury after three-dimensional conformal stereotactic radiation therapy for solitary lung tumors: CT appearance.

PURPOSE: To evaluate the computed tomographic (CT) appearance of tumors and lung injury in patients who have undergone stereotactic radiation therapy (SRT) for solitary lung tumors. MATERIALS AND METHODS: Twenty-seven patients with primary lung cancer and four with metastatic lung cancer who underwent SRT for solitary lung tumors were enrolled for evaluation. SRT was delivered by using a three-dimensional conformal technique with a stereotactic body frame. A total dose of 48 Gy was administered in four fractions during a period of 2 weeks. After SRT, follow-up CT images were obtained every 2-3 months. Radiation-induced pulmonary injuries were classified into four patterns on CT images. The minimal lung dose to areas demonstrating pulmonary injury at CT was evaluated, and the correlation between the dose and the percentage volume of the whole lung irradiated by more than 20 Gy in total (V20) was assessed by using Spearman rank correlation. RESULTS: Tumor shrinkage continued for 2-15 months after SRT. Asymptomatic changes in the irradiated lung were noted at CT in all patients within 2-6 months (median, 4 months) after SRT. As the pattern at pulmonary CT changed, patchy consolidation was more predominantly seen as an acute change than were slight homogeneous increase in opacity, discrete consolidation, or solid consolidation; solid consolidation was the more predominantly seen late change. The minimal lung dose to the area demonstrating pulmonary injury in each patient ranged between 16 and 36 Gy (median, 24 Gy). The dose was significantly (P <.001) inversely correlated with the V20 in each patient. CONCLUSION: The reaction to SRT of the lungs seems similar to the reaction to conventional radiation therapy.

Follow-Up Studies↗

Lung transplant edema: chest radiography after lung transplantation--the first 10 days.

PURPOSE: To determine the imaging spectrum and clinical correlates of lung transplant edema within the first 10 days after lung transplantation. MATERIALS AND METHODS: The study group consisted of 105 consecutive lung transplant recipients. Lung infiltrates on chest radiographs were scored and characterized. Findings that satisfied the accepted description of reperfusion edema were identified. Lung ischemia times and the clinical or biopsy diagnosis of acute rejection were correlated with radiographic findings. RESULTS: Lung infiltrates compatible with reperfusion edema were seen in 97% of transplanted lungs without a demonstrable correlation with lung ischemia times. Lung scores between groups of patients treated and not treated for acute rejection were not statistically significantly different. CONCLUSION: The spectrum of findings attributable to lung transplantation or reperfusion edema is variable and diminishes the use of chest radiography as an early postoperative modality for monitoring acute rejection.

Adult↗

Oxytocin-induced labor augments IL-1beta-stimulated lung fluid absorption in fetal guinea pig lungs.

We tested the hypothesis that oxytocin-induced labor augmented IL-1beta-induced/-stimulated lung fluid absorption in preterm guinea pig fetuses. IL-1beta was administered subcutaneously daily to timed-pregnant guinea pigs for 3 days with and without simultaneous cortisol synthesis inhibition by metyrapone. At day 3, oxytocin was administered, and fetuses were delivered by abdominal hysterotomy at 61 and by oxytocin-induced birth at 68 days gestation. Delivered fetuses were instilled with isosmolar 5% albumin into the lungs, and lung fluid movement was measured over 1 h by mass balance. Lung fluid absorption was induced in 61-day and stimulated in 68-day gestation lungs by IL-1beta. Labor induction by oxytocin augmented IL-1beta-induced/-stimulated lung fluid absorption. Metyrapone pretreatment did not affect oxytocin-induced/-stimulated lung fluid absorption, while completely blocking IL-1beta-induced/-stimulated fluid absorption. Fetal lung fluid absorption, when present, was always propranolol and amiloride sensitive, suggesting that beta-adrenoceptor stimulation and amiloride-sensitive sodium channels were critical for fluid absorption. Epithelial sodium channel and Na-K-ATPase subunit expressions were both increased by IL-1beta, but not further by oxytocin. Our results indicate that IL-1beta release into the maternal blood circulation positively affects lung maturation due to the IL-1beta-induced release of cortisol and thus prepares the lungs for the epinephrine surge associated with labor.

Absorption↗

Lung function reference values in Chinese children and adolescents in Hong Kong. II. Prediction equations for plethysmographic lung volumes.

As part of a comprehensive evaluation of lung function in Hong Kong Chinese children and adolescents, over a thousand healthy subjects aged 7-19 yr from seven schools were recruited for lung function testing that included spirometry and, in many cases, lung subdivision measurements. Lung function tests were performed using SensorMedics Automated Body Plethysmograph according to published standards. Of these, 551 subjects (219 males), aged 8-19 yr, had satisfactory lung subdivision indices recorded. Analysis for the values of lung subdivisions including total lung capacity (TLC), residual volume (RV), and functional residual capacity (FRC) demonstrated that standing height and sitting height were the best predictors of lung volumes. After allowing for standing height or sitting height in the regression models for lung volumes, age at examination was the second best parameter, although its inclusion into the equations contributed to less than 1% of explained variance for boys and 3% for girls. These are the first reported data in international literature on reference values for lung subdivisions in Chinese children and adolescents.

Adolescent↗

Impairment of bronchial mucociliary clearance in long-term survivors of heart/lung and double-lung transplantation. The Paris-Sud Lung Transplant Group.

The study objective was to investigate bronchial mucociliary clearance after heart/lung and double lung transplantation. Bronchial mucociliary clearance was measured using a noninvasive radioaerosol technique: 99mTc-labeled albumin was aerosolized using a spinning-top generator (mass median aerodynamic diameter, 7.5 mu; geometric standard deviation, 1.5 mu). Radioactivity counts were acquired during 60 min with a gamma camera. A region of interest was drawn over the right lung delineated by a 133Xe lung ventilation image. Bronchial mucociliary clearance was assessed as the percentage of decrease in radioactivity per hour calculated on time-activity curves fitted by a monoexponential model. To exclude patients with acute lung rejection, opportunistic lung infection, and obliterative bronchiolitis, all patients with transplants underwent pulmonary function tests and bronchoscopic examination before clearance measurement. Eight heart/lung and five double-lung nonsmoking transplant patients with normal lung histology were studied 19.3 +/- 4.0 mo after surgery and compared to nine normal nonsmokers. A similar proximal deposition of the aerosol was obtained in patients with transplants and normal subjects; skew values of distribution histograms of aerosol radioactivity counts were 2.1 +/- 0.2 and 1.8 +/- 0.1, respectively, and the ratios between central and peripheral 99mTc radioactivity counts were 2.4 +/- 0.1 and 2.3 +/- 0.2, respectively. No significant difference was observed in bronchial clearance values between patients with heart/lung and double-lung transplants (26.4 +/- 3.0 percent/h vs 35.9 +/- 3.5 percent/h). Conversely, bronchial clearance was significantly lower in transplant recipients (30.0 +/- 2.5 percent/h) than in normal controls (58.7 +/- 6.2 percent/h; p < 0.001). This decreased bronchial clearance can be expected to increase the risk of lung infection in long-term survivors of heart/lung and double-lung transplantation.

Adult↗

Combined operations for lung volume reduction surgery and lung cancer.

Fifty-three lung masses were found in 51 (16%) of 325 patients who underwent lung volume reduction surgery. This included 11 non-small cell lung cancers and 42 benign lung masses. Eleven patients (mean age, 69.4 years) underwent a combined lung volume reduction surgery and resection of clinical stage I lung cancers (lymph node dissection with either lobectomy [3] or wedge resection [8]). There were no deaths or major complications. The average length of stay was 8.7 days. The mean FEV1 was 654 mL (21.7% predicted) preoperatively and 1,079 mL (49% predicted) postoperatively. Patients who are screened for lung volume reduction surgery should be carefully evaluated for possible lung masses. Lung volume reduction surgery allows lung cancer surgery in patients who otherwise would be considered to have physiologically inoperable disease.

Aged↗

Protective effects of ischemic preconditioning on donor lung in canine lung transplantation.

BACKGROUND: Myocardial ischemic preconditioning has been found to protect the myocardium. We hypothesized that lung ischemic preconditioning might enhance canine lung preservation and reduce allograft lung dysfunction after transplantation. METHODS: Ten pairs of adult canines underwent left lung allotransplantation. Five donors were treated with ischemic preconditioning (their left hilus clamped for 10 min and released for 15 min [group IP]), and five donors were not treated with ischemic preconditioning (group C). The donor lungs were flushed with 4 degrees C Euro-Collins solution (ECS) and stored in the same solution for 2 1/2 h, then transplanted to the recipient canines. The animals were observed for 1 to 2 h after transplantation. The lung venous blood of the recipient and donor lung tissue was collected just after thoracotomy and 1 h after reperfusion of the transplanted lung in both groups. RESULTS: The numbers of polymorphonuclear leukocytes (PMNs) in the pulmonary venous blood after reperfusion were significantly higher in group IP than in group C (p<0.05). However, the numbers of PMNs in lung interstitium under microscopy were less in group IP than in group C. The thromboxane B2, malondialdehyde, and mean pulmonary artery pressure contents were significantly lower in group IP than in group C (p<0.05), and the superoxide dismutase and mixed venous oxygen tension values were significantly higher in group IP than in group C (p<0.05). Histologic findings show less damage in group IP than in group C. CONCLUSIONS: The protective effects of ischemic preconditioning in conjunction with ECS flush and storage were superior to using ECS alone. The possible mechanisms were that ischemic preconditioning inhibited the accumulation and activation of PMNs in lung tissue and reduced the production of oxygen-free radicals.

Animals↗

Glucose transporter expression in developing fetal lungs and lung neoplasms.

Glucose uptake and metabolism are essential for proliferation and survival of cells, and are supposed to be enhanced in actively proliferating cell systems such as embryonic and cancer tissues. Glucose uptake is usually carried out through glucose transporters. In the developing fetal lung, metabolism of glucose is thought to be an important process in cell proliferation, differentiation and maturation. Active glucose uptake could result in accumulation of glycogen in epithelial cells, and utilization of glycogen could be a critical phenomenon for lung epithelial development. In hamsters, although facilitative glucose transporter isoform 1 (GLUT1) and isoform 4 (GLUT4) are not detected in adult lungs, expression of them is detected with immunohistochemical and Western blot analyses in the developing fetal lungs. In human lung carcinomas, GLUT1 expression is seen in most cases of lung carcinoma, and is seen especially frequently in squamous cell carcinoma. GLUT1 expression in adenocarcinoma of the lung is correlated with reduced cell differentiation, larger tumor size and positive lymph node metastasis. A few cases of lung carcinoma show positive staining for GLUT3 and GLUT4. Thus, expression of some facilitative glucose transporter isoforms is detected in developing fetal epithelium and in lung carcinomas. Overexpression of them could enhance uptake of glucose into these cells, and the increased influx of glucose could be involved in active cell proliferation, which is a common character of the developing lung epithelium and carcinoma.

Animals↗

Lung elastic tissue maturation and perturbations during the evolution of chronic lung disease.

BACKGROUND: Infants <30 weeks' gestation have difficulty maintaining adequate functional residual capacity after the first week of life without positive end-expiratory pressure. We hypothesized that this is caused, in part, by increased lung elastic recoil. Our aims were to quantitate parenchymal elastic tissue during normal fetal development and in infants born at 23 to 30 weeks' gestation with prolonged survival at risk for chronic lung disease (CLD). METHODS: The controls were 22 to 42 weeks' gestation (n = 71), received ventilator care, and died within 48 hours of birth, plus 7 term infants who died at 43 to 50 weeks' postconceptional age from nonpulmonary causes. Infants who were 23 to 30 weeks' gestation, at risk for CLD, and who lived 5 to 59 days (n = 44), were separated into groups based on respiratory score (SCORE; The integrated area under the curve of the average daily fraction of inspired oxygen x mean airway pressure (cm H(2)O) over the number of days lived). The SCORE groups, <20, 21 to 69 and 70 to 200, related clinically to mild to severe lung disease. The lungs were tracheally perfused and formalin-fixed and total lung volume (TLV) was measured by water displacement. The paraffin-embedded lung blocks were stained with Miller's elastic stain. The parenchyma and parenchymal elastic tissue were point-counted. The absolute elastic tissue was calculated by multiplying TLV by the parenchymal and elastic fractions. Septal width, alveoli and alveolar duct diameters, and internal surface area (ISA) were also measured. RESULTS: In the controls, the volume density of parenchymal elastic tissue and absolute quantity of elastic tissue increased progressively from 22 to 50 weeks. In infants with CLD and SCORE >/=20, the volume density and absolute quantity of elastic tissue increased significantly. Mean absolute elastic tissue in the 20 to 69 group was 0.76 +/- 0.20 cm(3) greater than in the <20 group (0.46 +/- 0.10 cm(3)) who were similar to the controls, and the 70 to 200 group was 1.32 +/- 0.56 cm(3) greater than the 20 to 69 group. Elastic tissue for infants at risk for CLD, as a percent of predicted for same-age controls, rose linearly with increasing SCORE (r = 0.73; r(2) = 0.55). Control TLV and ISA were linearly related to age. Thirty-nine of the 44 CLD-risk infants had TLVs greater than controls. However, 77% with SCORE 20 to 200 had ISAs less than or equal to the control 95% confidence interval. Control septal width decreased sharply from 23 to 30 weeks, then gradually decreased to term. All infants with SCORE 70 to 200 and 80% of those with SCORE 20 to 69 had widths more than the control 95% confidence interval. Control alveolar and duct diameters doubled from 23 to 50 weeks and were significantly greater in infants with SCORES 20 to 200. DISCUSSION: Lung elastic tissue maturation is tightly controlled during fetal development. With increasing SCORE, elastic tissue increased >200%, accounting, in part, for the positive end-expiratory pressure needed to maintain end-expiratory lung volume in infants at risk for CLD. Saccule and duct diameters more than doubled, and septa thickened significantly in CLD. We propose the following sequence to be operative in CLD: at birth, the preterm infant (</=30 weeks) has inadequate elastic tissue and elastic recoil, but high surface tension recoil. After surfactant treatment, surface tension recoil markedly decreases, permitting the saccules and ducts, with very low elastic recoil, to be overstretched by volutrauma. The damaged lung responds with elastosis, distorted acinar growth, cellular influx, and upregulation of inflammatory and reparative proteins. This hypothesis can be summarized by the following terms: lung immaturity, inflammation, volutrauma, and elastic tissue alterations.

Elastic Tissue↗