Liver complications of haemoglobin H disease in adults.

Haemoglobin H (HbH) disease is a type of non-transfusion-dependent thalassaemia. This cross-sectional study aimed at determining the prevalence and severity of liver iron overload and liver fibrosis in patients with HbH disease. Risk factors for advanced liver fibrosis were also identified. A total of 80 patients were evaluated [median (range) age 53 (24-79) years, male 34%, non-deletional HbH disease 24%]. Patients underwent 'observed' T2-weighted magnetic resonance imaging examination for liver iron concentration (LIC) quantification, and transient elastography for liver stiffness measurement (LSM) and fibrosis staging. In all, 25 patients (31%) had moderate-to-severe liver iron overload (LIC ≥7 mg/g dry weight). The median LIC was higher in non-deletional than in deletional HbH disease (7·8 vs. 2.9 mg/g dry weight, P = 0·002). In all, 16 patients (20%) had advanced liver fibrosis (LSM >7.9 kPa) and seven (9%) out of them had probable cirrhosis (LSM >11.9 kPa). LSM positively correlated with age (R = 0·24, P = 0·03), serum ferritin (R = 0·36, P = 0·001) and LIC (R = 0·28, P = 0·01). In multivariable regression, age ≥65 years [odds ratio (OR) 4·97, 95% confidence interval (CI) 1·52-17·50; P = 0·047] and moderate-to-severe liver iron overload (OR 3·47, 95% CI 1·01-12·14; P = 0·01) were independently associated with advanced liver fibrosis. The findings suggest that regular screening for liver complications should be considered in the management of HbH disease.

Three-year experience of using venovenous extracorporeal membrane oxygenation for patients with severe respiratory failure.

OBJECTIVE: To present the 3-year experience of using venovenous extracorporeal membrane oxygenation for patients with severe respiratory failure in a single centre in Hong Kong. DESIGN: Case series. SETTING: A 19-bed Intensive Care Unit of a tertiary hospital in Hong Kong. PATIENTS: All patients who were managed with venovenous extracorporeal membrane oxygenation from 1 July 2010 to 30 June 2013 in the Intensive Care Unit. RESULTS: Overall, 31 patients (mean age, 42.2 years, standard deviation, 14.1 years; 21 males) received venovenous extracorporeal membrane oxygenation for the treatment of severe respiratory failure. Of these, 90.3% (28 patients) presented with pneumonia as the cause of the respiratory failure, and 22 of them had identifiable causes. A total of nine (29.0%) patients were diagnosed to have H1N1 infection. The median Murray score was 3.5 (interquartile range, 3.0-3.5); the median duration of venovenous extracorporeal membrane oxygenation support was 5.0 (2.8-8.6) days; and the median duration of mechanical ventilator support was 18.2 (7.8-27.9) days. The overall intensive care unit mortality was 19.4% (n=6). The overall in-hospital mortality and the 28-day mortality were both 22.6% (n=7). Among the 22 patients who had identifiable infective causes, those suffering from viral infection had lower intensive care unit and hospital mortality than those who had bacterial infection (8.3% vs 20.0%). All the H1N1 patients survived. Complications related to extracorporeal membrane oxygenation included severe bleeding (n=2; 6.5%) and mechanical complications of the circuits (n=3; 9.7%). CONCLUSIONS: Venovenous extracorporeal membrane oxygenation is an effective adjunctive therapy and can be used as a life-saving procedure for carefully selected patients with severe acute respiratory distress syndrome when the limits of standard therapy have been reached.

Shed syndecan-1 restricts neutrophil elastase from alpha1-antitrypsin in neutrophilic airway inflammation.

Persistent proteolytic imbalance in chronic inflammatory diseases has been ascribed to neutrophil elastase (NE)/antielastase imbalance in wound fluids. In sputum sols of patients with bronchiectasis, we found unopposed NE activity, despite overwhelming excess of the physiological antielastase, alpha(1)-antitrypsin (alpha(1)-AT). Western blot analysis found NE in a supramolecular complex with shed ectodomains of syndecan (Syn)-1 in sputum sol samples and, as such, inhibition of NE activity was incomplete, even with addition of exogenous alpha(1)-AT. To confirm that NE binding to heparan sulfate (HS) components of Syn-1 limits the antielastase effect, recombinant human Syn-1 was recovered from stable Syn-1 transfectants of a human B-lymphoid cell line (ARH-77). Western ligand blot confirmed that NE bound to HS moieties and alpha(1)-AT to the core protein of the recombinant product. Inhibition of NE activity by standard additions of alpha(1)-AT was incomplete unless Syn-1 had been deglycanated by heparitinase treatment. Surface plasmon resonance analysis revealed that NE binding to HS (equilibrium dissociation constant, approximately 14 nM) could be outcompeted by heparin variants. We conclude that the HS moiety of shed Syn-1 binds and restricts NE from inhibition by alpha(1)-AT.

Upregulation of ICAM-1 expression in bronchial epithelial cells by airway secretions in bronchiectasis.

The airway epithelium participates in chronic airway inflammation by expressing adhesion molecules that mediate the transmigration of neutrophils into the inflamed airways. We hypothesize that, in patients with bronchiectasis, cytokines in their bronchial secretions enhance the expression of intercellular cell adhesion molecule (ICAM-1) in the bronchial epithelium and thus contribute to sustained recruitment of neutrophils into the inflamed airways. In the present study, we investigated the effect of bronchial secretions on the regulation of ICAM-1 in bronchial epithelial cells, and its modulation by pharmacologic agents. The expression of ICAM-1 mRNA and protein in human bronchial epithelial cells upon exposure to sputum sol from subjects with bronchiectasis were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and ELISA, respectively. Modulating effects of dexamethasone, ibuprofen, MK-663 or triptolide on ICAM-1 regulation were investigated in vitro. We demonstrated that changes in ICAM-1 expression correlated with levels of TNF-alpha in the sputum sol, and treatment of sol samples with TNF-alpha antibodies attenuated both the increase in ICAM-1 mRNA and protein. The role of TNF-alpha was further demonstrated when TNF-alpha elicited dose dependent increase in ICAM-1 expression. The sputum effect could also be suppressed dose-dependently by pre-incubation of bronchial epithelial cells with dexamethasone, ibuprofen, MK-663 or triptolide. Evidence is thus provided for the upregulation of bronchial epithelial ICAM-1 expression by airway secretions in bronchiectasis and a specific role for TNF-alpha in the secretions. The success of drug attenuation of this upregulation provides insight into possible therapeutic paradigms in the management of the disease.

S-maltoheptaose targets syndecan-bound effectors to reduce smoking-related neutrophilic inflammation.

Cigarette smoke induces injury and neutrophilic inflammation in the airways of smokers. The stability and activity of inflammatory effectors, IL8 and neutrophil elastase (NE), can be prolonged by binding to airway heparan sulfate (HS)/syndecan-1, posing risk for developing chronic obstructive pulmonary disease(COPD). We hypothesize that antagonizing HS/syndecan-1 binding of the inflammatory effectors could reduce smoking-related neutrophil-mediated airway inflammation. Analysis of bronchoalveolar lavage fluid(BALF) of COPD patients found both total and unopposed NE levels to be significantly higher among smokers with COPD than non-COPD subjects. Similar NE burden was observed in smoke-exposed rats compared to sham air controls. We chose sulfated-maltoheptaose(SM), a heparin-mimetic, to antagonize HS/sydecan-1 binding of the inflammatory mediators in airway fluids and lung tissues of the smoke-exposed rat model. Airway treatment with SM resulted in displacement of CINC-1 and NE from complexation with bronchio-epithelial HS/syndecan-1, dissipating the chemokine gradient for neutrophil flux across to the bronchial lumen. Following SM displacement of NE from shed HS/syndecan-1 in bronchial fluids, NE became accessible to inhibition by α1-antitrypsin endogenous in test samples. The antagonistic actions of SM against syndecan-1 binding of NE and CINC-1 in smoke-exposed airways suggest new therapeutic opportunities for modulating airway inflammation in smokers with SM delivery.

Correlation between compositional and mechanical properties of human mesenchymal stem cell-collagen microspheres during chondrogenic differentiation.

Mesenchymal stem cell (MSC)-based engineering is promising for cartilage repair. However, the compositional mechanical relationship of the engineered structures has not been extensively studied, given the importance of such relationship in native cartilage tissues. In this study, a novel human MSC-collagen microsphere system was used to study the compositional mechanical relationship during in vitro chondrogenic differentiation using histological and biochemical methods and a microplate compression assay. The mechanical property was found positively correlating with newly deposited cartilage-relevant matrices, glycosaminoglycan, and type II collagen, and with the collagen crosslinker density, in agreement with the presence of thick collagen bundles upon structural characterization. On the other hand, the mechanical property negatively correlates with type I collagen and total collagen, suggesting that the initial collagen matrix scaffold of the microsphere system was being remodeled by the differentiating human MSCs. This study also demonstrated the application of a simple, sensitive, and nondestructive tool for monitoring the progression of chondrogenic differentiation of MSCs in tissue-engineered constructs and therefore contributes to future development of novel cartilage repair strategies.

Sputum sol neutrophil elastase activity in bronchiectasis: differential modulation by syndecan-1.

The persistently dominant activity of neutrophil elastase in bronchial secretions replete with antielastases is crucial to the pathogenesis of bronchiectasis. We hypothesize that components in the bronchial secretions bind neutrophil elastase and compromise the inhibitory efficiency of prevailing antielastases. Zymographic analysis of sputum sols from patients with bronchiectasis found elastase activity in a polydisperse, alcian blue-stained zone of high molecular mass. This suggested that neutrophil elastase was complexed with polyanionic partners. Western blot analysis found not only the polyanionic partner, heparan sulfate/syndecan-1, but also the physiological antielastases, secretory leukoproteinase inhibitor and alpha1-antitrypsin, in the complex. Both dissociative density gradient ultracentrifugation and heparin displacement revealed that elastase dissociated from heparan sulfate/syndecan-1 was fully inhibited by the endogenous antielastases. This contrasts with the effects of exogenous antielastases on sputum neutrophil elastase activity-that of alpha1-antitrypsin was limited, but that of secretory leukoproteinase inhibitor was facilitated. Similarly, complexed elastase on blots of sputum sol zymographs was bound and inhibited by exogenous secretory leukoproteinase inhibitor but not by exogenous alpha1-antitrypsin. Taken together, the results bring a new focus to heparan sulfate/syndecan-1 complexed with neutrophil elastase in inflamed bronchial secretions as a target for modulating elastase susceptibility to physiological antielastases.