Complexity of chronic asthma and chronic obstructive pulmonary disease: implications for risk assessment, and disease progression and control

Although assessment of asthma control is important to guide treatment, it is difficult since the temporal pattern and risk of exacerbations are often unpredictable. In this Review, we summarise the classic methods to assess control with unidimensional and multidimensional approaches. Next, we show how ideas from the science of complexity can explain the seemingly unpredictable nature of bronchial asthma and emphysema, with implications for chronic obstructive pulmonary disease. We show that fluctuation analysis, a method used in statistical physics, can be used to gain insight into asthma as a dynamic disease of the respiratory system, viewed as a set of interacting subsystems (eg, inflammatory, immunological, and mechanical). The basis of the fluctuation analysis methods is the quantification of the long-term temporal history of lung function parameters. We summarise how this analysis can be used to assess the risk of future asthma episodes, with implications for asthma severity and control both in children and adults.

Progression of atherosclerosis in ApoE-deficient mice that express distinct molecular forms of TNF-alpha

TNFalpha (TNF) critically regulates inflammation-driven atherosclerosis. Because the transmembrane (tmTNF) and soluble (sTNF) forms of TNF possess distinct immuno-modulatory properties, we hypothesized that they might differentially regulate atherosclerosis progression. Three groups of male ApoE(-/-) mice were studied: one expressing wild-type TNF (WT-TNF); one expressing exclusively a mutated non-cleavable form of TNF (KI-TNF); and one deficient in TNF (KO-TNF). Mice aged 5 weeks were fed the high-fat diet for 5 (T5) and 15 weeks (T15) or a standard chow diet for 15 weeks. At T5, in mice fed the high-fat diet, no significant differences in lesion area were observed among the three groups, either in valves or in aortas. At T15, lesion areas in valves were significantly lower in KO-TNF mice compared with those in WT-TNF mice, whereas in KI-TNF mice, they were intermediate between KO- and WT-TNF mice but not significantly different from these two groups. In aortas, lesions in KI-TNF were comparable to those of KO-TNF, both being significantly lower than those in WT-TNF. Theses differences were not linked to circulating lipids, or to macrophage, actin, and collagen contents of lesions. At T15, in mice fed the chow diet, lesion areas in valves and the aortic arch were not significantly different between the three groups. Levels of IL-6, IFNgamma, IL-10, and Foxp3 mRNAs in spleens and production of IL-6, IL-10, MCP-1, RANTES, and TNFR-2 by peritoneal macrophages at T15 of the high-fat diet showed a decrease in pro-inflammatory status, more marked in KO-TNF than in KI-TNF mice. Apoptosis was reduced only in KO-TNF mice. In conclusion, these data show that TNF effects on atherosclerosis development are detectable at stages succeeding fatty streaks and that wild-type TNF is superior to tmTNF alone in promoting atherosclerosis. TNF-dependent progression of atherosclerosis is probably linked to the differential production of pro-inflammatory mediators whether tmTNF is preponderant or essentially cleaved. Copyright (c) 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley ; Sons, Ltd.

Microfluidic fabrication of advanced microcapsules for use in self-healing materials

The proposed work aims to facilitate the development of a microfluidic platform for the production of advanced microcapsules containing active agents which can be the functional constituents of self-healing composites. The creation of such microcapsules is enabled by the unique flow characteristics within microchannels including precise control over shear and interfacial forces for droplet creation and manipulation as well as the ability to form a solid shell either chemically or via the addition of thermal or irradiative energy. Microchannel design and a study of the fluid dynamics and mechanisms for shell creation are undertaken in order to establish a fabrication approach capable of producing healing-agent-containing microcapsules. An in-depth study of the process parameters has been undertaken in order to elucidate the advantages of this production technique including precise control of size (i.e., monodispersity) and surface morphology of the microcapsules. This project also aims to aid the optimization of the mechanical properties as well as healing performance of self-healing composites by studying the effects of the advantageous properties of the as-produced microcapsules. Scale-up of the microfluidic fabrication using parallel devices on a single chip as well as on-chip microcapsule production and shape control will also be investigated. It will be demonstrated that microfluidic fabrication is a versatile approach for the efficient creation of functional microcapsules allowing for superior design of self-healing composites.

Agents used for chemoprevention of prostate cancer may influence PSA secretion independently of cell growth in the LNCaP model of human prostate cancer progression

BACKGROUND: The aim of this study was to evaluate the inhibitory growth effects of different potential chemopreventive agents in vitro and to determine their influence on PSA mRNA and protein expression with an established screening platform. METHODS: LNCaP and C4-2 cells were incubated with genistein, seleno-L-methionine, lycopene, DL-alpha-tocopherol, and trans-beta-carotene at three different concentrations and cell growth was determined by the MTT assay. PSA mRNA expression was assessed by quantitative real-time RT-PCR and secreted PSA protein levels were quantified by the microparticle enzyme immunoassay. RESULTS: Genistein, seleno-l-methionine and lycopene inhibited LNCaP cell growth, and the proliferation of C4-2 cells was suppressed by seleno-L-methionine and lycopene. PSA mRNA expression was downregulated by genistein in LNCaP but not C4-2 cells. No other compound tested altered PSA mRNA expression. PSA protein expression was downregulated by genistein, seleno-L-methionine, DL-alpha-tocopherol in LNCaP cells. In C4-2 cells only genistein significantly reduced the secretion of PSA protein. CONCLUSIONS: In the LNCaP progression model PSA expression depends on the compound, its concentration and on the hormonal dependence of the cell line used and does not necessarily reflect cell growth or death. Before potential substances are evaluated in clinical trials using PSA as a surrogate end point marker, their effect on PSA mRNA and protein expression has to be considered to correctly assess treatment response by PSA.

Bluetooth Enabled Ad-hoc Networks: Performance Evaluation of a Self-healing Scatternet Formation Protocol

Bluetooth wireless technology is a robust short-range communications system designed for low power (10 meter range) and low cost. It operates in the 2.4 GHz Industrial Scientific Medical (ISM) band and it employs two techniques for minimizing interference: a frequency hopping scheme which nominally splits the 2.400 - 2.485 GHz band in 79 frequency channels and a time division duplex (TDD) scheme which is used to switch to a new frequency channel on 625 μs boundaries. During normal operation a Bluetooth device will be active on a different frequency channel every 625 μs, thus minimizing the chances of continuous interference impacting the performance of the system. The smallest unit of a Bluetooth network is called a piconet, and can have a maximum of eight nodes. Bluetooth devices must assume one of two roles within a piconet, master or slave, where the master governs quality of service and the frequency hopping schedule within the piconet and the slave follows the master’s schedule. A piconet must have a single master and up to 7 active slaves. By allowing devices to have roles in multiple piconets through time multiplexing, i.e. slave/slave or master/slave, the Bluetooth technology allows for interconnecting multiple piconets into larger networks called scatternets. The Bluetooth technology is explored in the context of enabling ad-hoc networks. The Bluetooth specification provides flexibility in the scatternet formation protocol, outlining only the mechanisms necessary for future protocol implementations. A new protocol for scatternet formation and maintenance - mscat - is presented and its performance is evaluated using a Bluetooth simulator. The free variables manipulated in this study include device activity and the probabilities of devices performing discovery procedures. The relationship between the role a device has in the scatternet and it’s probability of performing discovery was examined and related to the scatternet topology formed. The results show that mscat creates dense network topologies for networks of 30, 50 and 70 nodes. The mscat protocol results in approximately a 33% increase in slaves/piconet and a reduction of approximately 12.5% of average roles/node. For 50 node scenarios the set of parameters which creates the best determined outcome is unconnected node inquiry probability (UP) = 10%, master node inquiry probability (MP) = 80% and slave inquiry probability (SP) = 40%. The mscat protocol extends the Bluetooth specification for formation and maintenance of scatternets in an ad-hoc network.

Inhibition of integrin alphavbeta6 on cholangiocytes blocks transforming growth factor-beta activation and retards biliary fibrosis progression

BACKGROUND ; AIMS: Integrin alphavbeta6 is highly expressed on certain activated epithelia, where it mediates attachment to fibronectin and serves as coreceptor for the activation of latent transforming growth factor (TGF)-beta1. Because its role in liver fibrosis is unknown, we studied alphavbeta6 function in vitro and explored the antifibrotic potential of the specific alphavbeta6 antagonist EMD527040. METHODS: Experimental liver fibrosis was studied in rats after bile duct ligation (BDL) and in Mdr2(abcb4)(-/-) mice. Different doses of EMD527040 were given to rats from week 2 to 6 after BDL and to Mdr2(-/-) mice from week 4 to 8. Liver collagen was quantified, and expression of alphavbeta6 and fibrosis-related transcripts was determined by quantitative reverse-transcription polymerase chain reaction. alphavbeta6-expressing cells, bile duct proliferation, and apoptosis were assessed histologically. The effect of EMD527040 on cholangiocyte adhesion, proliferation, apoptosis, and TGF-beta1 activation was studied in vitro. RESULTS: alphavbeta6 was highly expressed on proliferating bile duct epithelia in fibrosis, with 100-fold increased transcript levels in advanced fibrosis. EMD527040 attenuated bile ductular proliferation and peribiliary collagen deposition by 40%-50%, induced down-regulation of fibrogenic and up-regulation of fibrolytic genes, and improved liver architecture and function. In vitro alphavbeta6 inhibition reduced activated cholangiocyte proliferation, their adhesion to fibronectin, and endogenous activation of TGF-beta1 by 50% but did not affect bile duct apoptosis. CONCLUSIONS: Integrin alphavbeta6 is strongly up-regulated in proliferating bile duct epithelia and drives fibrogenesis via adhesion to fibronectin and auto/paracrine TGF-beta1 activation. Pharmacologic inhibition of alphavbeta6 potently inhibits the progression of primary and secondary biliary fibrosis.

Integrin alphavbeta6 is a marker of the progression of biliary and portal liver fibrosis and a novel target for antifibrotic therapies

BACKGROUND/AIMS: The integrin alphavbeta6 promotes proliferation of specialized epithelia and acts as a receptor for the activation of latent TGFbeta1. We studied alphavbeta6 expression in experimental and human liver fibrosis and the potential of its pharmacological inhibition for treatment of hepatic fibrosis. METHODS: alphavbeta6 expression was studied by quantitative PCR and immunohistochemistry in rats with cirrhosis due to bile duct ligation (BDL), administration of thioacetamide (TAA), in Mdr2(Abcb4)(-/-) mice with spontaneous biliary fibrosis, and in livers of patients with chronic hepatitis C (n=79) and end-stage liver disease due to various etiologies (n=18). The effect of a selective alphavbeta6 inhibitor was evaluated in Mdr2(Abcb4)(-/-) mice with ongoing fibrogenesis. RESULTS: Integrin beta6 mRNA increased with fibrosis stage in hepatitis C and was upregulated between 25- and 100-fold in TAA- and BDL-induced cirrhosis, in Mdr2(Abcb4)(-/-) mice and in human end-stage liver disease. alphavbeta6 protein was absent in normal livers and expressed de novo on (activated) bile duct epithelia and transitional hepatocytes. A single dose of the alphavbeta6 inhibitor injected into Mdr2(Abcb4)(-/-) mice significantly induced profibrolytic matrix metalloproteinases (MMP)-8 and -9 after 3 h, with a corresponding increase in extracellular matrix-degrading activities. In parallel profibrogenic transcripts (procollagen alpha1(I), TGFbeta2, and MMP-2) showed a trend of downregulation. CONCLUSIONS: (1) Integrin alphavbeta6 is induced de novo in rodent and human liver fibrosis, where it is expressed on activated bile duct epithelia and (transitional) hepatocytes during fibrosis progression. (2) In vivo a single dose of a small molecule alphavbeta6 inhibitor induced antifibrogenic and profibrolytic genes and activities, suggesting alphavbeta6 is a unique target for treatment of liver fibrosis.

Insulin-like growth factor I improves aspects of mycophenolate mofetil-impaired anastomotic healing in an experimental model

BACKGROUND: Patients taking immunosuppressants after transplantation may require intestinal surgery. Mycophenolate mofetil (MMF) has been found to impair the healing of colonic anastomoses in rats. This study examined whether insulin-like growth factor (IGF) I prevents MMF impairment of anastomotic healing. METHODS: Sixty-three rats were divided into three groups (MMF, MMF/IGF and control). Animals underwent a sigmoid colon anastomosis with a 6/0 suture, and were killed on days 2, 4 and 6 after surgery. Investigations included bursting pressure measurement, morphometric analysis, and assessment of mucosal proliferation by 5-bromo-2'-deoxyuridine and Ki67 immunohistochemistry of the anastomoses. RESULTS: The leak rate was three of 21, one of 20 and two of 20 in the MMF, MMF/IGF-I and control groups respectively. Anastomotic bursting pressures were significantly lower in the MMF group than in the control group on days 2 and 4, but there was no significant difference by day 6. Values in the MMF/IGF-I and control groups were similar. Colonic crypt depth was significantly reduced in MMF-treated animals on days 2 and 4, but this impairment was attenuated by IGF-I on day 4. Similarly, IGF-I reduced the negative impact of MMF on mucosal proliferation on days 2 and 6. CONCLUSION: Exogenous IGF-I improves some aspects of MMF-impaired anastomotic healing.

Genotype 3 is associated with accelerated fibrosis progression in chronic hepatitis C

BACKGROUND/AIMS: While several risk factors for the histological progression of chronic hepatitis C have been identified, the contribution of HCV genotypes to liver fibrosis evolution remains controversial. The aim of this study was to assess independent predictors for fibrosis progression. METHODS: We identified 1189 patients from the Swiss Hepatitis C Cohort database with at least one biopsy prior to antiviral treatment and assessable date of infection. Stage-constant fibrosis progression rate was assessed using the ratio of fibrosis Metavir score to duration of infection. Stage-specific fibrosis progression rates were obtained using a Markov model. Risk factors were assessed by univariate and multivariate regression models. RESULTS: Independent risk factors for accelerated stage-constant fibrosis progression (>0.083 fibrosis units/year) included male sex (OR=1.60, [95% CI 1.21-2.12], P<0.001), age at infection (OR=1.08, [1.06-1.09], P<0.001), histological activity (OR=2.03, [1.54-2.68], P<0.001) and genotype 3 (OR=1.89, [1.37-2.61], P<0.001). Slower progression rates were observed in patients infected by blood transfusion (P=0.02) and invasive procedures or needle stick (P=0.03), compared to those infected by intravenous drug use. Maximum likelihood estimates (95% CI) of stage-specific progression rates (fibrosis units/year) for genotype 3 versus the other genotypes were: F0-->F1: 0.126 (0.106-0.145) versus 0.091 (0.083-0.100), F1-->F2: 0.099 (0.080-0.117) versus 0.065 (0.058-0.073), F2-->F3: 0.077 (0.058-0.096) versus 0.068 (0.057-0.080) and F3-->F4: 0.171 (0.106-0.236) versus 0.112 (0.083-0.142, overall P<0.001). CONCLUSIONS: This study shows a significant association of genotype 3 with accelerated fibrosis using both stage-constant and stage-specific estimates of fibrosis progression rates. This observation may have important consequences for the management of patients infected with this genotype.

Progression of steroid-associated osteoporosis after heart transplantation

BACKGROUND: Osteoporosis has been recognized as an important side effect of long-term and of pulsed steroid application after heart transplantation. METHODS: In June 1989 a prospective clinical trial was started to study bone demineralization by quantitative computed tomographic scan. All patients received vitamin D and calcium. In group I (n = 30) synthetic calcitonin (40 Medical Research Council Standard Units subcutaneously per day was administered in 14-day cycles, whereas group II patients (n = 31) received a placebo preparation. Repeat trabecular and cortical quantitative computed tomographic scans of the thoracic (T12) and lumbar spine (L1, L2, L3) were obtained within 48 weeks after heart transplantation. RESULTS: Expressed as the means of T12, L1, L2, and L3, trabecular bone density decreased significantly from 100+/-24 to 79+/-29 mg/mL within 3 weeks after heart transplantation, followed by a further reduction to 67+/-29 mg/mL after 3 months in the calcitonin group. The values for cortical bone density decreased significantly from 229+/-37 to 202+/-40 mg/mL (calcitonin) 3 weeks after heart transplantation. Comparable results were obtained in the placebo group. In both groups bone density remained stable thereafter. Intergroup differences were not of statistical significance. CONCLUSIONS: In heart transplant recipients progressive trabecular bone demineralization is limited to the first 3 postoperative months. Thereafter, bone density remained stable. A positive effect of synthetic calcitonin in addition to prophylactic calcium and vitamin D application could not be proved by repeat quantitative computed tomography.

Comparative in vivo study on the healing qualities of four different presealed vascular prostheses

PURPOSE: The purpose of this article is to assess the healing qualities of presealed knitted polyester prostheses. METHODS: Thoracic aortic replacement was performed with grafts with four different coating materials-collagen (CP), albumin (AP), and two with gelatin (GP1/GP2)-in four groups of 15 pigs each. Two weeks, 6 weeks, and 6 months after operation, five pigs of each group were killed. Healing quality was assessed by morphometric analysis of the remaining coating, the extent of tissue ingrowth, and the thickness of the inner layer. RESULTS: The sealant was rapidly absorbed in all prostheses except for the AP (remaining coating at 2 weeks: GP1 22.1%, GP2 34.7%, and CP 68.0% vs AP 97.1% [p < 0.05]), remaining coating at 6 weeks: GP1/GP2 0% and CP 2.5% vs AP 76.7% (p < .01). At 6 months, remaining coating was only detectable in AP (21.5%). At 2 weeks the extent of tissue ingrowth ranged from 65.7% in GP1 and 75.3% in CP to 80% in GP2 versus 8.9% in AP (p < 0.05). There was a slow increase of tissue ingrowth until the sixth postoperative week (GP1 74.4%, GP2 85.0%, and CP 91.3% versus AP 19.6% [p < 0.01]). Thickness of the internal layer varied from 0.11 to 0.21 mm at 2 weeks in all grafts studied and from 1.02 mm (AP) and 1.28 mm (GP2) to 1.39 mm (GP1), versus 0.41 mm in the CP (p < 0.01) after 6 months of implantation. CONCLUSIONS: The type of coating significantly influences the healing properties of knitted polyester prostheses. When used for thoracic aortic replacement in pigs, AP coating clearly results in inferior healing compared with GP1/GP2 or CP impregnation, with digestion of the coating material and tissue ingrowth used as parameters. The thinnest internal layer was found in the CP prostheses, reflecting superior healing properties of this coating in the model studied.

The systemic angiogenic response during bone healing

INTRODUCTION: Angiogenesis is known to be a critical and closely regulated step during bone formation and fracture healing driven by a complex interaction of various cytokines. Delays in bone healing or even nonunion might therefore be associated with altered concentrations of specific angiogenic factors. These alterations might in turn be reflected by changes in serum concentrations. METHOD: To determine physiological time courses of angiogenic cytokines during fracture healing as well as possible changes associated with failed consolidation, we prospectively collected serum samples from patients who had sustained surgical treatment for a long bone fracture. Fifteen patients without fracture healing 4 months after surgery (nonunion group) were matched to a collective of 15 patients with successful healing (union group). Serum concentrations of angiogenin (ANG), angiopoietin 2 (Ang-2), basic fibroblast growth factor (bFGF), platelet derived growth factor AB (PDGF-AB), pleiotrophin (PTN) and vascular endothelial growth factor (VEGF) were measured using enzyme linked immunosorbent assays over a period of 24 weeks. RESULTS: Compared to reference values of healthy uninjured controls serum concentrations of VEGF, bFGF and PDGF were increased in both groups. Peak concentrations of these cytokines were reached during early fracture healing. Serum concentrations of bFGF and PDGF-AB were significantly higher in the union group at 2 and 4 weeks after the injury when compared to the nonunion group. Serum concentrations of ANG and Ang-2 declined steadily from the first measurement in normal healing fractures, while no significant changes over time could be detected for serum concentrations of these factures in nonunion patients. PTN serum levels increased asymptotically over the entire investigation in timely fracture healing while no such increase could be detected during delayed healing. CONCLUSION: We conclude that fracture healing in human subjects is accompanied by distinct changes in systemic levels of specific angiogenic factors. Significant alterations of these physiologic changes in patients developing a fracture nonunion over time could be detected as early as 2 (bFGF) and 4 weeks (PDGF-AB) after initial trauma surgery.

Periodontal disease progression in subjects with orofacial clefts over a 25-year follow-up period

AIMS: To assess rates of periodontal disease progression in subjects with cleft lip, alveolus and palate (CLAP) over a 25-year period without regular maintenance care in a specialist setting and to compare those with those of subjects without alveolar clefts, i.e. cleft lip (CL) or cleft palate (CP). MATERIAL AND METHODS: Ten subjects with CLAP and 10 subjects with CL/CP were examined in 1979, 1987, 1993 and 2004. Probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BoP) and plaque control record (PCR) scores were recorded in all 20 subjects. RESULTS: High plaque and BoP scores were recorded at all examinations in both groups. Over 25 years, a statistically significant loss of mean full-mouth CAL of 1.52 +/- 0.12 mm (SD) and 1.66 +/- 0.15 mm occurred in the CLAP and CL/CP group respectively (p<0.05). A statistically significant increase (p<0.05) in mean full-mouth PPD of 0.35 +/- 0.12 mm was observed in the CL/CP group, whereas only a trend for a mean full-mouth increase in PPD of 0.09 +/- 0.11 mm was observed in the CLAP group. In subjects with CLAP, a statistically significant increase (p<0.05) in PPD of 0.92 +/- 1.13 mm at cleft sites was observed compared with that of 0.17 +/- 0.76 mm at control sites. With respect to CAL, the loss at the corresponding sites amounted to 2.71 +/- 1.46 and to 2.27 +/- 1.62 mm, respectively (p=0.36). CONCLUSIONS: When stringent and well-defined supportive periodontal therapy was not provided, subjects with orofacial clefts were at high risk for periodontal disease progression. Over 25 years, alveolar cleft sites tended to have more periodontal tissue destruction compared with control sites.

Programmed death 1 signaling on chronic myeloid leukemia-specific T cells results in T-cell exhaustion and disease progression

Chronic myeloid leukemia (CML) is a malignant myeloproliferative disease with a characteristic chronic phase (cp) of several years before progression to blast crisis (bc). The immune system may contribute to disease control in CML. We analyzed leukemia-specific immune responses in cpCML and bcCML in a retroviral-induced murine CML model. In the presence of cpCML and bcCML expressing the glycoprotein of lymphocytic choriomeningitis virus as a model leukemia antigen, leukemia-specific cytotoxic T lymphocytes (CTLs) became exhausted. They maintained only limited cytotoxic activity, and did not produce interferon-gamma or tumor necrosis factor-alpha or expand after restimulation. CML-specific CTLs were characterized by high expression of programmed death 1 (PD-1), whereas CML cells expressed PD-ligand 1 (PD-L1). Blocking the PD-1/PD-L1 interaction by generating bcCML in PD-1-deficient mice or by repetitive administration of alphaPD-L1 antibody prolonged survival. In addition, we found that PD-1 is up-regulated on CD8(+) T cells from CML patients. Taken together, our results suggest that blocking the PD-1/PD-L1 interaction may restore the function of CML-specific CTLs and may represent a novel therapeutic approach for CML.