High frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice.

We tested the hypothesis that high frequency ventilation affects respiratory system mechanical functions in C57BL/6J and BALB/c mice. We measured respiratory mechanics by the forced oscillation technique over 1h in anesthetized, intubated, ventilated BALB/c and C57BL/6J male mice. We did not detect any change in airway resistance, Rn, tissue damping, G, tissue elastance, H and hysteresivity, eta in BALB/c mice during 1h of ventilation at 150 or at 450 breaths/min; nor did we find a difference between BALB/c mice ventilated at 150 breaths/min compared with 450 breaths/min. Among C57BL/6J mice, except for H, all parameters remained unchanged over 1h of ventilation in mice ventilated at 150 breaths/min. However, after 10 and 30 min of ventilation at 450 breaths/min, Rn, and respiratory system compliance were lower, and eta was higher, than their starting value. We conclude that high frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice.

Circadian disruption alters mouse lung clock gene expression and lung mechanics.

Most aspects of human physiology and behavior exhibit 24-h rhythms driven by a master circadian clock in the brain, which synchronizes peripheral clocks. Lung function and ventilation are subject to circadian regulation and exhibit circadian oscillations. Sleep disruption, which causes circadian disruption, is common in those with chronic lung disease, and in the general population; however, little is known about the effect on the lung of circadian disruption. We tested the hypothesis circadian disruption alters expression of clock genes in the lung and that this is associated with altered lung mechanics. Female and male mice were maintained on a 12:12-h light/dark cycle (control) or exposed for 4 wk to a shifting light regimen mimicking chronic jet lag (CJL). Airway resistance (Rn), tissue damping (G), and tissue elastance (H) did not differ between control and CJL females. Rn at positive end-expiratory pressure (PEEP) of 2 and 3 cmH(2)O was lower in CJL males compared with controls. G, H, and G/H did not differ between CJL and control males. Among CJL females, expression of clock genes, Bmal1 and Rev-erb alpha, was decreased; expression of their repressors, Per2 and Cry 2, was increased. Among CJL males, expression of Clock was decreased; Per 2 and Rev-erb alpha expression was increased. We conclude circadian disruption alters lung mechanics and clock gene expression and does so in a sexually dimorphic manner.

Hyperechoic congenital lung lesions in a non-selected population: from prenatal detection till perinatal management.

OBJECTIVE: To present longitudinal observations of hyperechoic lung lesions (HLL) in a non-selected population from the time of prenatal diagnosis by ultrasound (US) until postnatal surgery. METHODS: We conducted a retrospective study of all fetuses diagnosed with an HLL between 1990 and 2005 in our Fetal Medicine Unit. RESULTS: We observed 21 cases of HLL. Among the 17 fetuses with unilateral lesion, two cyst punctures were attempted on fetuses with signs of fetal compromise. Termination of pregnancy (TOP) was performed on seven fetuses. Fourteen fetuses were followed till birth. First Chest X-ray was abnormal in ten cases, while delayed CT scans revealed a lung lesion in 12 cases. Two neonates required emergency surgery and died post operatively. Surgery was successfully performed in all other cases (n = 10). Pathological examination revealed congenital high airway obstruction syndrome, CHAOS (n = 4), lower airway stenosis (n = 2), bronchogenic cyst (n = 1), congenital lobar emphysema (n = 1), and congenital cystic adenomatoid malformation, CCAM (n = 11) including two cases associated with a sequestration. CONCLUSION: HLL cover a wide spectrum of lung abnormalities of various severities. Post natal management should always include an early chest X-ray and CT scan to allow appropriate selection for surgery.

Invasive aspergillosis in a paediatric haematology department: a 15-year review.

Invasive aspergillosis (IA) is an increasingly common and often fatal fungal infection in children with haematological disorders. To describe the epidemiology, diagnosis, treatment and outcome of IA in children, retrospective review of the medical records of proven and probable IA between January 1986 and December 2000 was used. Twenty-four patients with IA were identified (10 proven and 14 probable) with a median age of 8.5 years. The incidence of IA was particularly high in acute myeloblastic leukaemia (5.35%) and leukaemia relapse (4%). Twenty-two patients presented with lung involvement. Broncho-alveolar lavage led to a diagnosis in 11 cases, but diagnosis was difficult and repeated invasive explorations were required. Antifungal therapy mainly consisted of amphotericin B. Eight patients underwent open-thorax surgery without any complication. Nine patients (37.5%) were cured of IA and three are still alive. The mortality was 87.5%. Three patients died of massive haemoptysis, including two before neutropenia recovery. Four patients presented with IA recurrence and three were cured again. Despite significant progress having been made in the treatment and diagnosis of IA, it is still a devastating complication in children with haematological disorders. New antifungal therapies and strategies are promising, but objective data are still lacking.

Congenital diaphragmatic hernia: a retinoid-signaling pathway disruption during lung development?

Congenital diaphragmatic hernia (CDH) usually occurs sporadically. The prognosis remains poor, with a 50% perinatal mortality rate. Most deaths result from hypoxemia due to lung hypoplasia and abnormal development of pulmonary vasculature that results in persistent pulmonary hypertension. Our current understanding of the pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. Pulmonary hypoplasia, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Moreover, a nitrofen-induced CDH model shows that lung hypoplasia precedes the diaphragmatic defect, leading to a "dual-hit hypothesis." Recent data reveal the role of a retinoid-signaling pathway disruption in the pathogenesis of CDH. We describe the clinical and epidemiological aspects of human CDH, the metabolic and molecular aspects of the retinoid-signaling pathway, and the implications of retinoids in the development of the diaphragm and the lung. Finally, we highlight the existing links between CDH and disruption of the retinoid-signaling pathway, which may suggest an eventual use of retinoids in the treatment of CDH.

Cytokine pattern in cystic fibrosis patients during antibiotic therapy and gene therapy using adenoviral vector.

Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Despite improvements in treatment, pulmonary disease still remains the primary cause of death among these patients. In order to introduce a normal CFTR gene copy into airway epithelial cells, adenoviral vectors (AV) have been developed. AV are known to induce an inflammatory reaction that limits transgene expression, and can be potentially harmful. No human study has clearly monitored simultaneously, systemic and local inflammatory reaction, during AV administration. We report here the levels of C-reactive protein (CRP), interleukin (IL)-6, IL-8, tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 receptor antagonist (IL-1Ra) in plasma and bronchoalveolar lavage fluid (BALF) from six cystic fibrosis patients receiving AV encoding CFTR (AdCFTR). AdCFTR was administered to three cohorts of two patients into the nose on day 0, at doses ranging from 105 to 4 x 108 plaque-forming units (pfu), followed, on day 1, by aerosolization of 107 to 5.4 x 108 pfu. In order to ensure that patients were in the best clinical condition, and to further attenuate the broncho-pulmonary inflammation secondary to bacterial infection, they received antibiotic therapy, two weeks prior to AdCFTR administration, until 9 to 11 days after. We found that antibiotics markedly decreased CRP, TNF-alpha, IL-6, IL-1Ra levels in blood. In BALF, antibiotics slightly decreased TNF-alpha levels but had no effect on IL-8 and IL-1Ra, while IL-6 levels increased. AdCFTR administration did not induce any systemic or local cytokine release. In both blood and BALF, CRP, IL-8, IL-1Ra, TNF-alpha decreased, while IL-6 levels increased between day -7 and day 3. One patient presented an asymptomatic increase of all parameters in the BALF on day 7. Twenty one days later, he displayed a clinical deterioration suggestive of an exacerbation. In conclusion, this study demonstrates that antibiotic administration tends to attenuate systemic but not local broncho-pulmonary inflammation in CF patients. In the setting of our study, AdCFTR administration did not induce cytokine release. Further studies are necessary to investigate other inflammatory markers and the mechanisms involved during AV-mediated gene transfer for a better understanding of the immune reaction, which continues to hamper the development of gene therapy for CF patients.

Obliterative airway disease progresses in heterotopic airway allografts without persistent alloimmune stimulus.

BACKGROUND: Up to 50% of human lung allografts develop chronic rejection manifested as obliterative bronchiolitis (OB). This complication frequently progresses despite maximal immunosuppression, suggesting that, once initiated, factors other than alloimmunity play a role in its progression. In animals, heterotopically transplanted allograft airways develop obliterative airway disease (OAD), an immunologically mediated lesion that is used as a preclinical model of OB. We sought to determine whether OAD would progress even after removal from the alloimmune environment. METHODS: Tracheas from Lewis rats were transplanted subcutaneously into Brown Norway recipients to create allografts. After 7 or 14 days of alloimmune stimulus, these allografts were removed and retransplanted into an isogeneic environment for an additional 21 days. Histology was assessed at each time point, with quantitation of the airway epithelium and intraluminal fibroproliferation. RESULTS: Allografts exposed to 14 days of alloimmune stimulus had a significant loss of airway epithelium compared with grafts exposed to only 7 days ( <0.001). There was little fibroproliferation seen in either of these groups. After retransplantation, the grafts initially exposed to 7 days of alloimmune stimulus had few abnormalities. In contrast, the group exposed initially to 14 days of alloimmunity and retransplanted had near complete obliteration of the lumen with fibroproliferation (96.9% occlusion, =0.001) and absent airway epithelium. CONCLUSIONS: OAD progresses despite removal of alloimmunity if the initial period of alloimmune injury is sufficient. Airway epithelial loss correlated with progression to fibroproliferation, suggesting that the epithelium plays a significant role in the pathogenesis of OB.

Chronic parvovirus B19 infection in a pediatric lung transplanted patient.

In immunocompromised patients, clinical manifestations of human parvovirus B19 (PVB19) infection are mostly reported as acute or chronic hematological disorders. Recently, PVB19 infection has been associated with nonhematological symptoms. Four years after lung transplantation, a 9-year-old girl developed a severe anemia with reticulocytopenia requiring blood transfusion. PVB19 DNA was found by polymerase chain reaction in blood. Blood marrow aspiration revealed typical features of PVB19 infection. She was successfully treated with high dose of i.v. Ig. Then, she exhibited recurrent nonregenerative anemia requiring another course of i.v. Ig. PVB19 DNA has been persisted in blood with no specific immune response. At the same time, she suffered from several lung infection syndromes with no microorganism found except PVB19 DNA. Recurrent mild renal dysfunction was noticed with no other explanation than PVB19 infection. This report indicates that pediatric transplanted patients are at risk of chronic PVB19 infection, which can be associated with lung and/or renal disorders.