Risk of coronary stenosis after adjuvant radiotherapy for breast cancer.

PURPOSE: Adjuvant radiotherapy (RT) for breast cancer is associated with an increased risk of ischemic heart disease. We examined the risk of coronary artery stenosis in a large cohort of women with breast cancer receiving adjuvant RT. METHODS: A cohort of women diagnosed with breast cancer between 1992 and 2012 in three Swedish health care regions (n = 57,066) were linked to the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) to identify women receiving RT who subsequently underwent a percutaneous coronary intervention (PCI) due to coronary stenosis. Cox regression analyses were performed to examine risk of a coronary intervention and competing risk analyses were performed to calculate cumulative incidence. RESULTS: A total of 649 women with left-sided breast cancer and 494 women with right-sided breast cancer underwent a PCI. Women who received left-sided RT had a significantly higher risk of a PCI in the left anterior descending artery (LAD) compared to women who received right-sided RT, hazard ratio (HR) 1.44 (95% confidence interval [CI] 1.21-1.77, p < 0.001). For the proximal, mid, and distal LAD, the HRs were 1.60 (95% CI 1.22-2.10), 1.38 (95% CI 1.07-1.78), and 2.43 (95% CI 1.33-4.41), respectively. The cumulative incidence of coronary events at 25 years from breast cancer diagnosis were 7.0% in women receiving left-sided RT and 4.4% in women receiving right-sided RT. CONCLUSION: Implementing and further developing techniques that lower cardiac doses is important in order to reduce the risk of long-term side effects of adjuvant RT for breast cancer.

Health status and health care utilization after discharge from geriatric in-hospital stay - description of a register-based study.

BACKGROUND: This study is the first part of a register-based research program with the overall aim to increase the knowledge of the health status among geriatric patients and to identify risk factors for readmission in this population. The aim of this study was two-fold: 1) to evaluate the validity of the study cohorts in terms of health care utilization in relation to regional cohorts; 2) to describe the study cohorts in terms of health status and health care utilization after discharge. METHODS: The project consist of two cohorts with data from patient records of geriatric in-hospital stays, health care utilization data from Stockholm Regional Healthcare Data Warehouse 6 months after discharge, socioeconomic data from Statistics Sweden. The 2012 cohort include 6710 patients and the 2016 cohort, 8091 patients; 64% are women, mean age is 84 (SD 8). RESULTS: Mean days to first visit in primary care was 12 (23) and 10 (19) in the 2012 and 2016 cohort, respectively. Readmissions to hospital was 38% in 2012 and 39% in 2016. The validity of the study cohorts was evaluated by comparing them with regional cohorts. The study cohorts were comparable in most cases but there were some significant differences between the study cohorts and the regional cohorts, especially regarding amount and type of primary care. CONCLUSION: The study cohorts seem valid in terms of health care utilization compared to the regional cohorts regarding hospital care, but less so regarding primary care. This will be considered in the analyses and when interpreting data in future studies based on these study cohorts. Future studies will explore factors associated with health status and re-admissions in a population with multi-morbidity and disability.

Evaluating the hip-flask defence using analytical data from ethanol and ethyl glucuronide. A comparison of two models.

AIM: Claimed intake of alcohol after a traffic incident, called the hip-flask defence, can be objectively assessed by different methods. One of them is the use of two consecutive ethanol concentrations in urine and the ratio between ethanol concentrations in urine and blood. Another one is the concentrations of ethyl glucuronide (EtG) and ethyl sulphate (EtS) in blood and their ratio to ethanol. The experimental basis for both these models is from single dose studies only. The aim of this study was therefore to describe the kinetics of ethanol, EtG and EtS after ingestion of two repeated doses of ethanol and to investigate the usefulness of the different models for the assessment of the hip-flask defence. METHODS: Thirty-five subjects ingested a first dose of 0.51 g of ethanol per kilo body weight, and two hours later a second dose (the hip-flask drink) of 0.25, 0.51 or 0.85 g of ethanol per kilo body weight. Ten urine and 17 blood samples were collected and analysed for ethanol, EtG and EtS using fully validated methods. It was investigated if all subjects fulfilled the criteria for recent drinking, according to the two different models, when using the samples collected 180-240 minutes after start of first dose drinking. According to the first model, increase in urinary ethanol concentrations and a ratio UAC/BAC below 1.3 indicated recent drinking. According to the second model, increase in blood EtG concentrations and a ratio ethanol (g/kg)/EtG (mg/L) above 1 indicated recent drinking. RESULTS: All subjects in the high dose group fulfilled all criteria for recent drinking. One subject in the medium dose group and nine subjects in the low dose group failed to show increasing UAC and/or a UAC/BAC ratio below 1.3. One subject in the low dose group failed to show increasing concentrations of blood EtG, but all subjects showed a ratio ethanol/EtG above 1. CONCLUSIONS: The present study showed, by the use of experimental data, that both two models used to investigate the hip-flask defence can be used, but only when the hip-flask dose is sufficiently high.

Hand-held cardiac ultrasound examinations performed in primary care patients by nonexperts to identify reduced ejection fraction.

BACKGROUND: Early identification of patients with reduced left ventricular ejection fraction (LVEF) could facilitate the care of patients with suspected heart failure (HF). We examined if (1) focused cardiac ultrasound (FCU) performed with a hand-held device (Vscan 1.2) could identify patients with LVEF < 50%, and (2) the distribution of HF types among patients with suspected HF seen at primary care clinics. METHODS: FCU performed by general practitioners (GPs)/GP registrars after a training programme comprising 20 supervised FCU examinations were compared with the corresponding results from conventional cardiac ultrasound by specialists. The agreement between groups of estimated LVEF < 50%, after visual assessment of global left ventricular function, was compared. Types of HF were determined according to the outcomes from the reference examinations and serum levels of natriuretic peptides (NT-proBNP). RESULTS: One hundred patients were examined by FCU that was performed by 1-4 independent examiners as well as by the reference method, contributing to 140 examinations (false positive rate, 19.0%; false negative rate, 52.6%; sensitivity, 47.4% [95% confidence interval [CI]: 27.3-68.3]; specificity, 81.0% [95% CI: 73.1-87.0]; Cohen's κ measure for agreement = 0.22 [95% CI: 0.03-0.40]). Among patients with false negative examinations, 1/7 had HF with LVEF < 40%, while the others had HF with LVEF 40-49% or did not meet the full criteria for HF. In patients with NT-proBNP > 125 ng/L and fulfilling the criteria for HF (68/94), HF with preserved LVEF (≥50%) predominated, followed by mid-range (40-49%) or reduced LVEF (< 40%) HF types (53.2, 11.7 and 7.4%, respectively). CONCLUSIONS: There was poor agreement between expert examiners using standard ultrasound equipment and non-experts using a handheld ultrasound device to identify patients with reduced LVEF. Asides from possible shortcomings of the training programme, the poor performance of non-experts could be explained by their limited experience in identifying left ventricular dysfunction because of the low percentage of patients with HF and reduced ejection fraction seen in the primary care setting. TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov (NCT02939157). Registered 19 October 2016.

Meta-analysis of neoadjuvant therapy and its impact in facilitating breast conservation in operable breast cancer.

BACKGROUND: Neoadjuvant therapy (NAT) for operable breast cancer may facilitate more breast-conserving surgery (BCS). It seems, however, that this benefit is not being realized fully. METHODS: A systematic review of the literature was performed. RCTs were included. The criteria for inclusion were: documentation of surgical assessment before and after NAT, surgery performed (BCS or mastectomy), and clinical and pathological responses. RESULTS: A total of 1452 patients from seven RCTs met the inclusion criteria. After NAT, the feasibility of BCS increased from 43·3 to 60·4 per cent (P < 0·001), but BCS was performed in only 51·8 per cent (P = 0·04). Only 31 per cent of patients who became eligible for BCS (assessed on clinical response) underwent BCS (pooled rate ratio 0·31, 95 per cent c.i. 0·22 to 0·44; P < 0·001). Of the mastectomy candidates who achieved a pathological complete response after NAT, only 41 per cent underwent BCS (pooled rate ratio 0·41, 0·23 to 0·74; P = 0·003). The main factors that influenced the decision not to shift to BCS, even though it was feasible, were clinical assessment before NAT, multicentricity and tumour size at presentation. CONCLUSION: Breast surgery performed after NAT does not reflect tumour response, resulting in potentially unnecessary radical surgery, especially mastectomy. The barriers to maximizing the surgical benefits of NAT need to be better understood and explored.

Mast cell-dependent IL-33/ST2 signaling is protective against the development of airway hyperresponsiveness in a house dust mite mouse model of asthma.

Interleukin-33 (IL-33) and its receptor ST2 have been influentially associated with the pathophysiology of asthma. Due to the divergent roles of IL-33 in regulating mast cell functions, there is a need to further characterize IL-33/ST2-dependent mast cell responses and their significance in the context of asthma. This study aimed to investigate how IL-33/ST2-dependent mast cell responses contribute to the development of airway hyperresponsiveness (AHR) and airway inflammation in a mouse model of house dust mite (HDM)-induced asthma. Mast cell-deficient C57BL/6-KitW-sh (Wsh) mice engrafted with either wild-type (Wsh + MC-WT) or ST2-deficient bone marrow-derived mast cells (Wsh + MC-ST2KO) were exposed to HDM delivered intranasally. An exacerbated development of AHR in response to HDM was seen in Wsh + MC-ST2KO compared with Wsh + MC-WT mice. The contribution of this IL-33/ST2-dependent mast cell response to AHR seems to reside within the smaller airways in the peripheral parts of the lung, as suggested by the isolated yet marked effect on tissue resistance. Considering the absence of a parallel increase in cellular inflammation in bronchoalveolar lavage fluid (BALF) and lung, the aggravated AHR in Wsh + MC-ST2KO mice seems to be independent of cellular inflammation. We observed an association between the elevated AHR and reduced PGE2 levels in BALF. Due to the protective properties of PGE2 in airway responses, it is conceivable that IL-33/ST2-dependent mast cell induction of PGE2 could be responsible for the dampening effect on AHR. In conclusion, we reveal that IL-33/ST2-dependent mast cell responses can have a protective, rather than causative role, in the development of AHR.

Interleukin 33 exacerbates antigen driven airway hyperresponsiveness, inflammation and remodeling in a mouse model of asthma.

Interleukin 33 (IL-33) represents a potential link between the airway epithelium and induction of Th2-type inflammatory responses associated with the development of asthma. This study investigated the potential of IL-33 to exacerbate antigen driven asthma responses. An ovalbumin (OVA) asthma model was used in which sensitized C57BL/6 mice were exposed to IL-33 before each OVA challenge. IL-33 given to sensitized mice acted synergistically with antigen and aggravated airway inflammation, hyperresponsiveness and remodeling compared with mice that were only OVA sensitized and challenged and mice that were only exposed to IL-33. Elevated levels of local and systemic mast cell protease mMCP-1, as well as antigen-specific IgE production, were observed following IL-33 administration to sensitized mice. Similarly, exposing OVA-sensitized mice to IL-33 increased the Th2 cytokine levels, including IL-4, IL-5 and IL-13. Furthermore, IL-33 and OVA administration to OVA-sensitized mice increased ILC2s in the lung, suggesting a role for ILC2s in IL-33-mediated exacerbation of OVA-induced airway responses. Collectively, these findings show that IL-33 aggravates important features of antigen-driven asthma, which may have implications for asthma exacerbations.

Assessment of in vivo mast cell reactivity in patients with systemic mastocytosis.

BACKGROUND: Patients with systemic mastocytosis (SM) have clinical signs of mast cell (MC) activation and increased levels of MC mediators. It is unclear whether the increased mediator levels are caused by increased numbers of tissue MCs, or whether these cells in affected individuals have a hyperactive phenotype. OBJECTIVE: To determine reactivity of the skin and the airways to directly acting mediators and indirectly acting mast cell secretagogues in subjects with SM. METHODS: Skin reactivity to morphine and histamine, and airway responsiveness to mannitol and methacholine, was assessed in 15 patients with SM, 11 patients with allergic asthma (A) and 13 healthy controls (HC). Serum tryptase and urinary metabolites of the MC mediators histamine and prostaglandin D2 were measured, as well as ex vivo basophil histamine release. RESULTS: Mast cell mediators in the blood and urine were significantly higher in patients with SM than in HC and A controls. Responsiveness to local activation of skin MCs (by morphine) and airway MCs (by mannitol) was similar in SM and HC groups. Likewise, end-organ responsiveness in the skin to histamine, and in the airways to methacholine, was similar in all three subject groups. There was no evidence of increased basophil reactivity in SM patients. CONCLUSIONS AND CLINICAL RELEVANCE: Mast cells in the skin and airways of subjects with SM do not exhibit hyper-reactivity towards the MC-activating stimuli morphine and mannitol, respectively. Therefore, the highly elevated baseline levels of MC mediators in SM are most likely due to increased MC numbers, rather than altered MC responsiveness. The underlying mechanisms could involve leakage of MC mediators, or dysfunctions in mediator synthesis, storage and release. One clinical implication of our study is that there is no contraindication to perform skin tests using morphine in subjects with mastocytosis.

Abstracts of the 24th international isotope society (UK group) symposium: synthesis and applications of labelled compounds 2015.

The 24th annual symposium of the International Isotope Society's United Kingdom Group took place at the Møller Centre, Churchill College, Cambridge, UK on Friday 6th November 2015. The meeting was attended by 77 delegates from academia and industry, the life sciences, chemical, radiochemical and scientific instrument suppliers. Delegates were welcomed by Dr Ken Lawrie (GlaxoSmithKline, UK, chair of the IIS UK group). The subsequent scientific programme consisted of oral presentations, short 'flash' presentations in association with particular posters and poster presentations. The scientific areas covered included isotopic synthesis, regulatory issues, applications of labelled compounds in imaging, isotopic separation and novel chemistry with potential implications for isotopic synthesis. Both short-lived and long-lived isotopes were represented, as were stable isotopes. The symposium was divided into a morning session chaired by Dr Rebekka Hueting (University of Oxford, UK) and afternoon sessions chaired by Dr Sofia Pascu (University of Bath, UK) and by Dr Alan Dowling (Syngenta, UK). The UK meeting concluded with remarks from Dr Ken Lawrie (GlaxoSmithKline, UK).

Tetraspanin CD151 and integrin α6ß1 mediate platelet-enhanced endothelial colony forming cell angiogenesis.

UNLABELLED: ESSENTIALS: Platelet releasates (PRs) enhance endothelial colony forming cell (ECFC) angiogenesis. The impact of platelet membrane components on ECFC angiogenesis was studied by a tube formation assay. Platelets enhanced ECFC angiogenesis more potently than PR, via tetraspanin CD151 and integrin α6ß1. Optimal enhancement of ECFC angiogenesis by platelets requires both membrane proteins and PR. BACKGROUND: Platelets promote angiogenesis of endothelial colony forming cells (ECFCs), with the underlying mechanisms not being fully understood. OBJECTIVE: To investigate if platelets regulate the angiogenic property of ECFCs via mechanisms beyond platelet-released angiogenic regulators. METHODS AND RESULTS: Endothelial colony forming cells were generated by ECFC-directed cell culture of peripheral blood mononuclear cells. Capillary-like tube formation of ECFCs was assessed using a Matrigel assay. Platelets promoted ECFC tube formation in both basic and complete ECFC medium. Importantly, the ECFC angiogenic responses induced by platelets were stronger than those induced by platelet releasates. Thus, the branching points of ECFC tube formation (30.5 ± 9.0/field, ECFC alone) were increased by platelet releasates (58.2 ± 8.3/field) and even more profoundly by platelets (95.5 ± 17.6/field), indicating that platelet membrane components also promoted ECFC tube formation. The latter was further supported by evidence that fixed platelets did enhance ECFC tube formation. Subsequent experiments revealed that the promotion was dependent on platelet-surface glycoproteins, as removal of sialic acid from platelet glycoproteins by neuraminidase abolished the enhancement. Furthermore, platelet-expressed, but not ECFC-expressed, CD151 was important for the enhancement, as pretreatment of platelets, but not ECFCs, with a CD151-blocking antibody attenuated the effect. Integrin α6ß1 on both ECFCs and platelets also participated in platelet-promoted tube formation, as integrin α6 or ß1 blockade of either cell type markedly or totally inhibited the phenomenon. Moreover, platelets exerted the enhancement via the Src-PI3K signaling pathway of ECFCs. CONCLUSION: Platelet-enhanced ECFC angiogenesis requires platelet tetraspanin CD151 and α6ß1 integrin, as well as ECFC α6ß1 integrin and Src-PI3K signaling.

Mastocytosis: the puzzling clinical spectrum and challenging diagnostic aspects of an enigmatic disease.

Mastocytosis is a complex disorder characterized by the accumulation of abnormal mast cells (MC) in the skin, bone marrow and/or other visceral organs. The clinical manifestations result from MC-derived mediators and, less frequently, from destructive infiltration of MCs. Patients suffer from a variety of symptoms including pruritus, flushing and life-threatening anaphylaxis. Whilst mastocytosis is likely to be suspected in a patient with typical skin lesions [i.e. urticaria pigmentosa (UP)], the absence of cutaneous signs does not rule out the diagnosis of this disease. Mastocytosis should be suspected in cases of recurrent, unexplained or severe insect-induced anaphylaxis or symptoms of MC degranulation without true allergy. In rare cases, unexplained osteoporosis or unexplained haematological abnormalities can be underlying feature of mastocytosis, particularly when these conditions are associated with elevated baseline serum tryptase levels. The diagnosis is based on the World Health Organization criteria, in which the tryptase level, histopathological and immunophenotypic evaluation of MCs and molecular analysis are crucial. A somatic KIT mutation, the most common of which is D816V, is usually detectable in MCs and their progenitors. Once a diagnosis of systemic mastocytosis (SM) is made, it is mandatory to assess the burden of the disease, its activity, subtype and prognosis, and the appropriate therapy. Mastocytosis comprises seven different categories that range from indolent forms, such as cutaneous and indolent SM, to progressive forms, such as aggressive SM and MC leukaemia. Although prognosis is good in patients with indolent forms of the disease, patients with advanced categories have a poor prognosis.

The interleukin-33 receptor ST2 is important for the development of peripheral airway hyperresponsiveness and inflammation in a house dust mite mouse model of asthma.

BACKGROUND: Several clinical and experimental studies have implicated IL-33 and its receptor ST2 in the development of asthma. However, the effect of IL-33/ST2 signalling on airway responses and inflammation in allergic asthma is not well established. OBJECTIVE: To investigate the role of IL-33/ST2 signalling in promoting allergen-induced airway hyperresponsiveness (AHR), airway inflammation, antigen-specific IgE production and mast cell activity in a mouse model of asthma. METHODS: ST2-deficient (ST2(-/-)) mice and control BALB/c mice were given house dust mite (HDM) extract over a 6-week period. Forty-eight hours after the final HDM administration, lung function and airway inflammation were evaluated. Airway responsiveness was determined in the central airways and peripheral lung. Cellular infiltration and mast cell protease mMCP-1 levels were quantified in bronchoalveolar lavage fluid (BALF). Recruitment of inflammatory cells and inflammatory cytokine profiles were assessed in pulmonary tissue, and HDM-specific IgE was measured in serum. RESULTS: ST2 deficiency diminished HDM-induced AHR in the peripheral lung, while AHR in the central airways was unaffected. Inflammatory responses to HDM were also reduced in ST2(-/-) mice as reflected by the lower induction of HDM-specific serum IgE, inhibition of HDM-induced eosinophilia and reduced macrophage count in BALF, and a diminished influx of inflammatory cells and reduced goblet cell hyperplasia around the peripheral airways. Furthermore, the levels of the inflammatory cytokines IL-1ß, IL-5, IL-13, IL-33, GM-CSF, thymic stromal lymphopoietin and mast cell protease mMCP-1 were reduced in HDM-treated ST2(-/-) mice compared with wild-type controls. CONCLUSIONS: In addition to promoting Th2 inflammation, we now suggest a role for the IL-33/ST2 pathway for the induction of peripheral inflammation and mucus production that causes AHR in the peripheral lung. This mechanism for inducing AHR at distal parts of the lung may be of specific importance as asthma is considered as a small airway disease.

Anxiety and depression among out-of-hospital cardiac arrest survivors.

AIM: Survivors of out-of-hospital cardiac arrest (OHCA) may experience psychological distress but the actual prevalence is unknown. The aim of this study was to investigate anxiety and depression within a large cohort of OHCA-survivors. METHODS: OHCA-survivors randomized to targeted temperature of 33 °C or 36 °C within the Target Temperature Management trial (TTM-trial) attended a follow-up after 6 months that included the questionnaire Hospital Anxiety and Depression Scale (HADS). A control group with ST-elevation myocardial infarction (STEMI) completed the same follow-up. Correlations to variables assumed to be associated with anxiety and depression in OHCA-survivors were tested. RESULTS: At follow-up 278 OHCA-survivors and 119 STEMI-controls completed the HADS where 24% of OHCA-survivors (28% in 33 °C group/22% in 36 °C group, p=0.83) and 19% of the STEMI-controls reported symptoms of anxiety (OR 1.32; 95% CI (0.78-2.25), p=0.30). Depressive symptoms were reported by 13% of OHCA-survivors (equal in both intervention groups, p=0.96) and 8% of STEMI-controls (OR 1.76; 95% CI (0.82-3.79), p=0.15). Anxiety and depression among OHCA-survivors correlated to Health-Related Quality-of-Life, and subjectively reported cognitive deterioration by patient or observer. In addition, depression was associated with a poor neurological outcome. CONCLUSION: One fourth of OHCA-survivors reported symptoms of anxiety and/or depression at 6 months which was similar to STEMI-controls and previous normative data. Subjective cognitive problems were associated with an increased risk for psychological distress. Since psychological distress affects long-term prognosis of cardiac patients in general it should be addressed during follow-up of survivors with OHCA due to a cardiac cause. ClinicalTrials.gov NCT01020916/NCT01946932.

Intermittent pneumatic compression reduces the risk of deep vein thrombosis during post-operative lower limb immobilisation: a prospective randomised trial of acute ruptures of the Achilles tendon.

Deep vein thrombosis is a common complication of immobilising the lower limb after surgery. We hypothesised that intermittent pneumatic compression (IPC) therapy in outpatients who had undergone surgical repair of acute ruptures of the Achilles tendon could reduce the incidence of this problem. A total of 150 patients who had undergone surgical repair of the Achilles tendon were randomised to either treatment with IPC for six hours per day (n = 74) under an orthosis or treatment as usual (n = 74) in a plaster cast without IPC. At two weeks post-operatively, the incidence of deep vein thrombosis was assessed using blinded, double-reported compression duplex ultrasound. At this point, IPC was discontinued and all patients were immobilised in an orthosis for a further four weeks. At six weeks post-operatively, a second compression duplex ultrasound scan was performed. At two weeks, the incidence of deep vein thrombosis was 21% in the treated group and 37% in the control group (p = 0.042). Age over 39 years was found to be a strong risk factor for deep vein thrombosis (odds ratio (OR) = 4.84, 95% confidence interval (CI) 2.14 to 10.96). Treatment with IPC, corrected for age differences between groups, reduced the risk of deep vein thrombosis at the two-week point (OR = 2.60; 95% CI 1.15 to 5.91; p =0.022). At six weeks, the incidence of deep vein thrombosis was 52% in the treated group and 48% in the control group (OR 0.94, 95% CI 0.49 to 1.83). IPC appears to be an effective method of reducing the risk of deep vein thrombosis in the early stages of post-operative immobilisation of outpatients. Further research is necessary to elucidate whether it can confer similar benefits over longer periods of immobilisation and in a more heterogeneous group of patients.

Interleukin-33 exacerbates allergic bronchoconstriction in the mice via activation of mast cells.

BACKGROUND: Interleukin-33 (IL-33) is implicated as an epithelium-derived danger signal promoting Th2-dependent responses in asthma. We hypothesized that IL-33 might also have direct effects on mast cell-driven allergic airway obstruction. METHODS: The effects of IL-33 on allergic responses in the airways of sensitized mice were assessed both in vivo and ex vivo, as well as on cultured mast cells in vitro. RESULTS: In vivo, the allergen-induced increase in resistance in the conducting airways was enhanced in mice pretreated with IL-33. Also, in the isolated airways, the allergen-induced contractions were increased in preparations from animals subjected to intranasal IL-33 pretreatment. These effects in vivo and ex vivo were blocked by the 5-HT2A receptor antagonist ketanserin and absent in mice without mast cells. Likewise, the IL-33-induced enhancement of the allergen response was absent in isolated airways from mice lacking the IL-33 receptor. Moreover, exposure to IL-33 increased secretion of serotonin from allergen-challenged isolated airways. In cultured mast cells, IL-33 enhanced the expression of tryptophan hydroxylase 1, serotonin synthesis, and storage, as well as the secretion of serotonin following IgE receptor cross-linking. CONCLUSION: These results demonstrate that IL-33 exacerbates allergic bronchoconstriction by increasing synthesis, storage, and secretion of serotonin from the mast cell. This mechanism has implications for the development of airway obstruction in asthma.

Eotaxin-3 (CCL26) exerts innate host defense activities that are modulated by mast cell proteases.

BACKGROUND: During bacterial infections of the airways, a Th1-profiled inflammation promotes the production of several host defense proteins and peptides with antibacterial activities including ß-defensins, ELR-negative CXC chemokines, and the cathelicidin LL-37. These are downregulated by Th2 cytokines of the allergic response. Instead, the eosinophil-recruiting chemokines eotaxin-1/CCL11, eotaxin-2/CCL24, and eotaxin-3/CCL26 are expressed. This study set out to investigate whether these chemokines could serve as innate host defense molecules during allergic inflammation. METHODS: Antibacterial activities of the eotaxins were investigated using viable count assays, electron microscopy, and methods assessing bacterial permeabilization. Fragments generated by mast cell proteases were characterized, and their potential antibacterial, receptor-activating, and lipopolysaccharide-neutralizing activities were investigated. RESULTS: CCL11, CCL24, and CCL26 all showed potent bactericidal activity, mediated through membrane disruption, against the airway pathogens Streptococcus pneumoniae, Staphylococcus aureus, Nontypeable Haemophilus influenzae, and Pseudomonas aeruginosa. CCL26 retained bactericidal activity in the presence of salt at physiologic concentrations, and the region holding the highest bactericidal activity was the cationic and amphipathic COOH-terminus. Proteolysis of CCL26 by chymase and tryptase, respectively, released distinct fragments of the COOH- and NH2 -terminal regions. The COOH-terminal fragment retained antibacterial activity while the NH2 -terminal had potent LPS-neutralizing properties in the order of CCL26 full-length protein. An identical fragment to NH2 -terminal fragment generated by tryptase was obtained after incubation with supernatants from activated mast cells. None of the fragments activated the CCR3-receptor. CONCLUSIONS: Taken together, the findings show that the eotaxins can contribute to host defense against common airway pathogens and that their activities are modulated by mast cell proteases.

PAR1-stimulated platelet releasate promotes angiogenic activities of endothelial progenitor cells more potently than PAR4-stimulated platelet releasate.

BACKGROUND: Endothelial progenitor cells (EPCs) are important for endothelial regeneration and angiogenesis. Thrombin protease-activated receptor 1 (PAR1) PAR1 and PAR4 stimulation induces selective release of platelet proangiogenic and antiangiogenic regulators. OBJECTIVE: To investigate if PAR1-stimulated platelet releasate (PAR1-PR) and PAR4-PR regulate angiogenic properties of EPCs in different manners. METHODS AND RESULTS: EPCs were generated from peripheral mononuclear cell culture. Washed platelets (2 × 10(9) mL(-1)) were stimulated by PAR1-activating peptide (PAR1-AP; 10 µmol L(-1)) or PAR4-AP (100 µmol L(-1)) to prepare PAR1-PR and PAR4-PR, respectively. PAR1-PR or PAR4-PR had little influence on EPC proliferation. EPC migration experiments using a modified Boyden chamber showed that both platelet releasates facilitated EPC migration. As for in vitro tube formation on Matrigel, PAR1-PR and PAR4-PR similarly enhanced capillary-like network formation of EPCs in the complete EPC medium containing 10% FBS and a cocktail of growth factors, while PAR1-PR more profoundly increased EPC tube formation in basal culture medium supplemented with only 0.5% FBS than did PAR4-PR. The latter was confirmed in the murine angiogenesis model of subcutaneous Matrigel implantation. Moreover, blockade of vascular endothelial growth factor, stromal cell-derived factor 1α, or matrix metalloproteinases attenuated EPC migration and tube formation, suggesting a cooperation of these factors in the enhancements. CONCLUSIONS: PAR1-PR enhances vasculogenesis more potently than PAR4-PR, and the enhancements require a cooperation of multiple platelet-derived angiogenic regulators.

Analysis of V600E BRAF and D816V KIT mutations in systemic mastocytosis.

Most patients with systemic mastocytosis (SM) carry a D816 V KIT mutation causing a ligand-independent activation of the receptor. Down-stream of KIT is several components known to be mutated in different malignancies. RAF is among the most frequently mutated kinases, where BRAF V600E mutation occurs in most hairy cell leukemias (HCL) and half of malignant melanomas. We investigated BRAF mutations in 36 subjects with different forms of SM, but could not detect BRAF mutation in any of the cases, not even in the mast cell lineage of a patient with V600E BRAF-positive HCL. Thus, although BRAF is commonly mutated it appears not to be present in SM.

The presence of mast cell clonality in patients with unexplained anaphylaxis.

BACKGROUND: The mechanisms by which mast cells in patients with unexplained anaphylaxis (UEA) are triggered remain elusive. Onset of episodes is unpredictable and often recurrent. The substantial overlap between the clinical manifestations of UEA and clonal mast cell disorders (CMD) suggests an association between these rare disorders. The two forms of CMD characterized to date are systemic mastocytosis (SM) and monoclonal mast cell activation syndrome (MMAS). OBJECTIVE: To examine the hypothesis that the pathogenesis of UEA reflects the presence of aberrant subpopulations of mast cells. METHODS: Thirty (14 men, 16 women) patients (≥ 18 years) suffering from UEA and with no signs of cutaneous mastocytosis were recruited. Patients underwent an initial complete allergy work-up to confirm the diagnosis of UEA. Level of baseline serum tryptase (sBT) and total IgE were determined. In addition, a bone marrow examination was performed on all 30 patients to investigate possible underlying CMD. RESULTS: Fourteen (47%) of our cases (nine men, five women) were diagnosed with CMD: 10 with SM and four with MMAS. Four of the 10 patients with SM had mast cell aggregates in their bone marrow. All patients with SM exhibited a sBT level > 11.4 ng/mL, whereas this level was elevated in only two of those with MMAS and four with UAE but not diagnosed with CMD. Total IgE levels were lower in the group of patients with CMD (P < 0.03). CONCLUSION AND CLINICAL RELEVANCE: The pathogenic mechanism underlying UEA could be explained by the presence of immunophenotypically aberrant mast cells with clonal markers in 47% of our subjects, indicating that clonal mast cell disorders are present in a substantial subset of these patients. Thus, the presence of CMD should be considered in patients with UEA if they have an elevated level of sBT (≥ 11.4 ng/mL) and cardiovascular symptoms such as syncope.