Ole Henning Skjønsberg

Local activation of the coagulation and fibrinolysis systems in lung disease

Extravascular coagulation and fibrinolysis is an integral part of inflammatory reactions. Disordered expression of procoagulant and profibrinolytic factors by mononuclear phagocytes of the lung (i.e. lung alveolar macrophages (LAM) and interstitial macrophages) may have important bearings on inflammatory lung tissue destruction and repair. Based on this hypothesis we have measured the presence of trigger molecules and activation products of the coagulation and fibrinolytic system in cell-free bronchoalveolar lavage fluid and in bronchoalveolar cells. Patient groups with chronic obstructive disease (COLD) (n = 76), idiopathic pulmonary fibrosis (IPF) (n = 29), sarcoidosis (n = 22), lung cancer (n = 36), pneumonia (n = 39), acquired immunodeficiency syndrome (AIDS) (n = 17) and a control group (n = 60) were studied by bronchoalveolar lavage (BAL). In all patient groups tissue thromboplastin (TPL) and fibrinopeptide A (FPA) were significantly increased compared to controls. Plasminogen activator (PA) activity was significantly lower in patients than in normals, and usually associated with high levels of antifibrinolytic activity. The level of PA inhibitor (PAI-2) was not significantly higher in any patient group compared to controls. The sensitivity of the method for fibrin degradation products (FDP) analysis was not high enough to detect FDP in BAL fluid of control individuals, whereas such products could be demonstrated in 25-53% of patients in various categories. We conclude that disordered expression of procoagulant and plasminogen activator activities in bronchoalveolar lavage fluid may reflect a milieu that favours accumulation of fibrin in inflammatory lung tissue and form the basis for the development of pulmonary fibrosis.

Hypoxaemia in chronic obstructive pulmonary disease patients during a commercial flight.

The aim of the study was to investigate hypoxaemia in chronic obstructive pulmonary disease patients during a commercial flight. The effect of a commercial flight, lasting 5 h 40 min, on arterial blood gas levels and symptoms in 18 chronic obstructive pulmonary disease patients with a pre-flight percutaneous oxygen saturation of ≥94% and self-reported ability to walk 50 m without severe dyspnoea was studied. The arterial oxygen tension (Pa,O2) decreased from sea level to cruising altitude (10.3±1.2 versus 8.6±0.8 kPa), but, thereafter, except for one patient, remained stable throughout the flight. During light exercise, however, there was further desaturation (percutaneous oxygen saturation 90±4 versus 87±4%). After 4 h, a decrease in arterial carbon dioxide tension (5.0±0.4 versus 4.8±0.4 kPa) and an increase in cardiac frequency (87±13 versus 95±13 beats·min-1) were observed. A pre-flight Pa,O2 of >9.3 kPa did not secure an acceptable in-flight Pa,O2. Aerobic capacity showed the strongest correlation with in-flight Pa,O2. In conclusion, following an initial decrease in arterial oxygen tension, chronic obstructive pulmonary disease patients in a stable state of their disease seem to maintain a stable arterial oxygen tension throughout a flight of intermediate duration, except when walking along the aisle. However, a decrease in arterial carbon dioxide tension, indicating compensatory hyperventilation, could imply a risk of respiratory fatigue during longer flights.

Relationship between exercise desaturation and pulmonary haemodynamics in COPD patients

Pulmonary hypertension (PH) in patients with chronic obstructive pulmonary disease (COPD) has traditionally been explained as an effect of hypoxaemia. Recently, other mechanisms, such as arterial remodelling caused by inflammation, have been suggested. The aim of this study was to investigate whether exercise-induced PH (EIPH) could occur without concurrent hypoxaemia, and whether exercise-induced hypoxaemia (EIH) was regularly accompanied by increased pulmonary artery pressure or pulmonary vascular resistance index (PVRI). Pulmonary haemodynamics in 17 patients with COPD of varying severity, but with no or mild hypoxaemia at rest, were examined during exercise equivalent to the activities of daily living (ADL) and exhaustion. EIPH occurred in 65% of the patients during ADL exercise. Pulmonary arterial pressure during exercise was negatively correlated with arterial oxygen tension, but EIPH was not invariably accompanied by hypoxaemia. Conversely, EIPH was not found in all patients with EIH. The resting PVRI was negatively correlated with arterial oxygen tension during ADL exercise, but an elevated PVRI without EIH occurred in 35% of the patients. In conclusion, exercise-induced pulmonary hypertension occurred during exercise equivalent to the activities of daily living in chronic obstructive pulmonary disease patients with no or mild hypoxaemia at rest. Although pulmonary artery pressure and arterial oxygen tension were negatively correlated during exercise, a consistent relationship between hypoxaemia and pulmonary hypertension could not be demonstrated. This may indicate that mechanisms other than hypoxaemia contribute significantly in the development of pulmonary hypertension in these patients.

High-intensity training following lung cancer surgery: a randomised controlled trial

Background Many patients with lung cancer are deconditioned with poor physical fitness. Lung resection reduces physical fitness further, impairing the patients ability to function in daily life. Methods We conducted a single-blind randomised controlled trial of high-intensity endurance and strength training (60 min, three times a week, 20 weeks), starting 5–7 weeks after surgery. The control group received standard postoperative care. The primary outcome was the change in peak oxygen uptake measured directly during walking until exhaustion. Other outcomes included changes in pulmonary function, muscular strength by one-repetition maximum (1RM), total muscle mass measured by dual energy X-ray absorptiometry, daily physical functioning and quality of life (QoL). Results The intention-to-treat analysis of the 61 randomised patients showed that the exercise group had a greater increase in peak oxygen uptake (3.4 mL/kg/min between-group difference, p=0.002), carbon monoxide transfer factor (Tlco) (5.2% predicted, p=0.007), 1RM leg press (29.5 kg, p<0.001), chair stand (2.1 times p<0.001), stair run (4.3 steps, p=0.002) and total muscle mass (1.36 kg, p=0.012) compared with the controls. The mean±SD QoL (SF-36) physical component summary score was 51.8±5.5 and 43.3±11.3 (p=0.006), and the mental component summary score was 55.5±5.3 and 46.6±14.0 (p=0.015) in the exercise and control groups, respectively. Conclusions In patients recently operated for lung cancer, high-intensity endurance and strength training was well tolerated and induced clinically significant improvements in peak oxygen uptake, Tlco, muscular strength, total muscle mass, functional fitness and QoL. This study may provide a basis for exercise therapy after lung cancer surgery. Trial registration number NCT01748981.

Thrombin generation during collection and storage of blood.

Abstract. Thrombin generation, as evidenced by radioimmunologic fibrinopeptide A (FPA) determination, was studied upon drawing and storage of blood. Blood from 5 healthy subjects was drawn into Fenwal bap (PL 146, 16‐gauge needle, 92‐cm collecting tube), and blood samples for FPA analysis were taken from the proximal and distal part of the collecting tubes. The FPA concentrations were considerably higher in the distal part of the tubes both at zero time and after 5 and 10 min, implying substantial thrombin generation to have occurred upon blood passing through the tubes. In 20 healthy blood donors (age 19–52 years) subjected to a standard collection procedure (Fenwal bags PL 146, CPDA formula‐1 anticoagulant solution, 450 ml blood), higher FPA values were observed in the bags immediately upon collection, as compared to control venipuncture values (p<0.02). Furthermore, in 6 women using oral contraceptives, even larger increases were observed, indicating thrombin generation to be more pronounced in such donors (p<0.01). No statistically significant increase in FPA concentrations was found upon storage of CPDA‐blood at 4°C for 24 h. There was no correlation between FPA and beta‐thromboglobulin (BTG) concentrations after blood collection, indicating alpha‐granule release from platelets to be non‐thrombin‐mediated.

Elevated levels of activin A in clinical and experimental pulmonary hypertension.

Activin A, a member of the transforming growth factor (TGF)-beta superfamily, is involved in regulation of tissue remodeling and inflammation. Herein, we wanted to explore a role for activin A in pulmonary hypertension (PH). Circulating levels of activin A and its binding protein follistatin were measured in patients with PH (n = 47) and control subjects (n = 14). To investigate synthesis and localization of pulmonary activin A, we utilized an experimental model of hypoxia-induced PH. In mouse lungs, we also explored signaling pathways that can be activated by activin A, such as phosphorylation of Smads, which are mediators of TGF-beta signaling. Possible pathophysiological mechanisms initiated by activin A were explored by exposing pulmonary arterial smooth muscle cells in culture to this cytokine. Elevated levels of activin A and follistatin were found in patients with PH, and activin A levels were significantly related to mortality. Immunohistochemistry of lung autopsies from PH patients and lungs with experimental PH localized activin A primarily to alveolar macrophages and bronchial epithelial cells. Mice with PH exhibited increased pulmonary levels of mRNA for activin A and follistatin in the lungs, and also elevated pulmonary levels of phosphorylated Smad2. Finally, we found that activin A increased proliferation and induced gene expression of endothelin-1 and plasminogen activator inhibitor-1 in pulmonary artery smooth muscle cells, mediators that could contribute to vascular remodeling. Our findings in both clinical and experimental studies suggest a role for activin A in the development of various types of PH.

Production of oxidants in alveolar macrophages and blood leukocytes

Increased production of oxidants subsequent to phagocyte stimulation has been associated with tissue damage in lung inflammatory disorders. The overall oxidative burden of the lung may vary with inflammatory cell composition. Flow cytometry using three different dyes, dihydroethidium (DHE), dichlorofluorescein diacetate (DCFH-DA) and dihydrorhodamine 123 (DHR), all compounds that by interaction with oxidants are transformed to fluorescent products, was used to examine the production of intracellular oxidants in alveolar macrophages (AMs), including size-defined subpopulations, monocytes (Ms) and polymorphonuclear neutrophils (PMNs) during in vitro incubation in the presence or absence of phorbol myristate acetate (PMA). PMA stimulation led to slightly increased (two-fold) (p<0.05) DHE-induced fluorescence in AMs, whereas it was greatly increased in Ms and PMNs (13-fold and 113-fold, respectively). The levels of DCFH-DA- and DHR-induced fluorescence were significantly (p<0.05) increased (four-fold and 110-fold, respectively) by PMA stimulation of PMNs, but not of AMs and Ms. Significant differences (p<0.05) in the levels of DHE- and DCFH-DA-induced fluorescence in small and large AMs were also demonstrated. The results show that the potential to increase the generation of various oxidants upon stimulation was: PMNs> Ms>AMs, suggesting that the total oxidative burden of the lungs is dependent on the type of inflammatory cells present, as well as on their state of activation.

Diastolic dysfunction in alveolar hypoxia: a role for interleukin-18-mediated increase in protein phosphatase 2A

AIMS Chronic obstructive pulmonary disease with alveolar hypoxia is associated with diastolic dysfunction in the right and left ventricle (LV). LV diastolic dysfunction is not caused by increased afterload, and we recently showed that reduced phosphorylation of phospholamban at serine (Ser) 16 may explain the reduced relaxation of the myocardium. Here, we study the mechanisms leading to the hypoxia-induced reduction in phosphorylation of phospholamban at Ser16. METHODS AND RESULTS In C57Bl/6j mice exposed to 10% oxygen, signalling molecules were measured in cardiac tissue, sarcoplasmic reticulum (SR)-enriched membrane preparations, and serum. Cardiomyocytes isolated from neonatal mice were exposed to interleukin (IL)-18 for 24 h. The beta-adrenergic pathway in the myocardium was not altered by alveolar hypoxia, as assessed by measurements of beta-adrenergic receptor levels, adenylyl cyclase activity, and subunits of cyclic AMP-dependent protein kinase. However, alveolar hypoxia led to a significantly higher amount (124%) and activity (234%) of protein phosphatase (PP) 2A in SR-enriched membrane preparations from LV compared with control. Serum levels of an array of cytokines were assayed, and a pronounced increase in IL-18 was observed. In isolated cardiomyocytes, treatment with IL-18 increased the amount and activity of PP2A, and reduced phosphorylation of phospholamban at Ser16 to 54% of control. CONCLUSION Our results indicate that the diastolic dysfunction observed in alveolar hypoxia might be caused by increased circulating IL-18, thereby inducing an increase in PP2A and a reduction in phosphorylation of phospholamban at Ser16.

Pulse oximetry in the preflight evaluation of patients with chronic obstructive pulmonary disease.

INTRODUCTION In a British Thoracic Society (BTS) statement on preflight evaluation of patients with respiratory disease, sea level pulse oximetry (Spo2sl) is recommended as an initial assessment. The present study aimed to evaluate if the BTS algorithm can be used to identify chronic obstructive pulmonary disease (COPD) patients in need of supplemental oxygen during air travel, i.e. patients with an in-flight PaO2 < 6.6 kPa (50 mmHg). METHODS There were 100 COPD patients allocated to groups according to the BTS algorithm: Spo2sl > 95%, Spo2sl 92-95% without additional risk factors; Spo2sl 92-95% with additional risk factors; Spo2sl < 92%; and patients using domiciliary oxygen. Pulse oximetry, arterial blood gases, and an hypoxia-altitude simulation test (HAST) to simulate a cabin altitude of 2438 m (8000 ft), were performed. RESULTS The percentage of patients in the various groups dropping below 6.6 kPa during HAST were: Spo2sl > 95%: 30%; Spo2sl 92-95% without additional risk factors: 67%; Spo2sl 92-95% with additional risk factors: 70%; Spo2sl < 92%: 83%; and patients using domiciliary oxygen: 81%. In patients dropping below P(a)o(2) 6.6 kPa, supplemental oxygen of median 1 L x min(-1) was needed to exceed this limit. DISCUSSION If in-flight P(a)o(2) > or = 6.6 kPa is regarded as a strict requirement, the use of pulse oximetry as an initial assessment in the preflight evaluation of COPD patients, as suggested by the BTS, might not discriminate adequately between patients who fulfill the indications for supplemental oxygen during air travel, and patients who can travel without such treatment.

Does Lp(a) lipoprotein inhibit the fibrinolytic system

Lp(a) lipoprotein contains a unique apolipoprotein, apolipoprotein (a), that has a striking homology with plasminogen. This homology has brought forward speculations as to an inhibitory effect of Lp(a) lipoproteins on fibrinolysis. The present investigation was undertaken to study the influence of Lp(a) lipoprotein on the fibrinolytic system. In an in vitro model, we have studied the influence of purified Lp(a) lipoprotein on plasminogen activation by tissue plasminogen activator (t-PA) in the presence of soluble fibrin. Increasing concentrations of Lp(a) lipoprotein (0-32 mg/dl) did not inhibit plasminogen activation by t-PA in the presence of thrombin or bathroxobin digested fibrinogen. When purified Lp(a) lipoprotein was added to whole blood, the degree of fibrin degradation obtained following standardized coagulation, as evaluated by the generation of D-dimer, was not reduced. D-dimer levels in plasma and in serum after standardized coagulation, as well as conventional parameters for evaluation of the fibrinolytic system, were determined in 10 individuals with high and 10 individuals with low levels of Lp(a) lipoprotein. No differences in the fibrinolytic parameters were observed between the groups. Thus, we found no evidence that Lp(a) lipoprotein interferes with the fibrinolytic process in the present experiments.