Adnexal torsion recurrence-is the adnexal twist degree a risk factor? A retrospective cohort study.

OBJECTIVE: To evaluate whether the adnexal twist degree is related to torsion recurrence and whether there is a dose-dependent correlation. DESIGN: A retrospective cohort study. SETTING: Single tertiary medical centre. POPULATION: The study includes non-pregnant patients operated, for the first time, for adnexal torsion, between 2011 and 2018. METHODS: Information regarding the degree of adnexal twist was collected from surgical reports. Recurrence was identified using a computerised database and ascertained via telephone with a response rate of 87.2% (253/290). MAIN OUTCOME MEASURES: Adnexal torsion recurrence rate. RESULTS: A total of 182 women who had undergone laparoscopic detorsion met the inclusion criteria. Twenty-two had torsion recurrence (12.1%). Adnexal twist degree in the primary event was associated with a higher recurrence risk: 4.3% of women with twist degree ≤360 (n = 3/70), 14.5% of women with twist degree of 361-720 (n = 9/62) and 20% of women with twist degree >720 (n = 10/50) (P = 0.03). The median twist degree was 540 (interquartile range [IQR] 360-855) and 720 (IQR 675-1080) degrees in the control and study groups, respectively (P = 0.005). Additional possibly associated factors for recurrence were evaluated. Age emerged as a possible risk factor, with a median age of 19 years in the recurrence group (IQR 14-27 years) versus 28.5 (IQR 19-36 years) in the non-recurrence group (P < 0.01). Logistic regression analysis revealed that together with age, adnexal twist degree remained significantly associated with torsion recurrence (odds ratio [OR] 1.98, 95% CI 1.09-3.61; P = 0.02). CONCLUSION: Adnexal twist degree was found to be positively associated with the risk of torsion recurrence. TWEETABLE ABSTRACT: Adnexal twist degree was found to be positively associated with the risk of torsion recurrence.

Association of serum ghrelin with weight gain during pregnancy in overweight and normal women.

PURPOSE: Despite the fact that the ghrelin hormone plays pivotal role in the process of weight gain, its correlation with weighing during pregnancy has not been elucidated. Hence, the present study was conducted to evaluate the correlation between plasma ghrelin levels and gestational weight gain in overweight and normal women. METHODS: This prospective cohort study was conducted in 27 overweight and 18 normal body mass index (BMI) pregnant women referring to Tehran health care centers. Weight gain during all trimesters of pregnancy was measured and the blood samples were collected at 8-12 (first trimester) and 16-20 weeks (second trimester) of pregnancy. The plasma total ghrelin concentration was measured by ELISA method. RESULTS: The overweight pregnant women exhibited significantly lower weight gain at the second (p = 0.002), third trimesters (p = 0.005) as well as total weighing during pregnancy (p = 0.001) compared to the normal BMI pregnant women. There was no significant difference in plasma ghrelin levels between the groups from the first to the second trimesters of pregnancy (p > 0.05). Moreover, no correlation was found between ghrelin levels and gestational weight gain in the overweight and normal groups. CONCLUSIONS: Our results indicate that the increased level of serum ghrelin could not be considered as a key mediator for weight gain difference during pregnancy of overweight women.

Monocytes enhance neutrophil-induced blister formation in an ex vivo model of bullous pemphigoid.

BACKGROUND: Lesions of bullous pemphigoid (BP), an autoimmune subepidermal blistering disease characterized by the presence of tissue-bound and circulating autoantibodies to hemidesmosomal antigens, harbor a mixed inflammatory cellular infiltrate. In various models, neutrophils, eosinophils, mast cells, monocytes as well as B and T cells have been shown to be involved in the pathogenesis of BP. However, their interactions with and effective role in blister formation remain uncertain. This study was aimed at investigating the effect of monocyte/neutrophil interaction on blister formation in an ex vivo BP model. METHODS: Skin cryosections were incubated with purified human neutrophils and monocytes, in the presence or absence of BP autoantibodies. Production of reactive oxygen species (ROS), degranulation, mediator release (neutrophil elastase [NE], myeloperoxidase [MPO], matrix metalloproteinase-9 [MMP-9]), binding of Fcγ receptor (CD16, CD32, CD64), and cell adhesion (CD18, ICAM-1) was investigated using appropriate inhibitors. Dermal-epidermal separation (DES) was assessed by light microscopy and quantified by Fiji software. RESULTS: Monocytes and neutrophils synergistically interact resulting in a significantly higher DES compared to either monocytes or neutrophils separately (P < .0001). Monocyte/neutrophil-induced DES was associated with increased ROS production and was dependent on adhesion and FcγRIII binding. Upon stimulation by the granule-poor fraction of monocyte supernatants, neutrophils increased their release of MMP-9, thereby also DES at the dermal-epidermal junction of skin cryosections. CONCLUSION: Our observations suggest that the interaction of cells, as shown here for monocytes and neutrophils, enhances mediator release resulting in an increased subepidermal blister formation. Thus, blocking intercellular cross talk promises a new therapeutic approach for blocking tissue damage in BP.

Pentoxifylline mitigates detrimental impact of chronic nonbacterial prostatitis on sperm characteristics, reproductive hormones and histopathology in rats.

The protective role of pentoxifylline (PTX) on sperm characteristics, reproductive hormones and histopathology following carrageenan-induced chronic nonbacterial prostatitis (CNP) was investigated in male Wistar rats. Thirty-six rats were grouped into six rats per group. Group 1 (control) received saline normal. Group 2 received a single intraprostatic dose of 3% carrageenan (50 µl) on day 1 (CNP). Groups 3 and 5 received cernilton (standard drug) and PTX orally at 100 and 50 mg/kg for 14 consecutive days respectively. Groups 4 and 6 received a single dose of 3% carrageenan (50 µl) intraprostatically on day 1 followed by cernilton and PTX orally at 100 and 50 mg/kg on the eighth day for 14 consecutive days respectively. Prostatic index, serum prostatic specific antigen, malondialdehyde, testosterone and luteinising hormone levels were significantly increased (p < .05), whereas serum follicle-stimulating hormone, sperm count, motility and viability were significantly decreased (p < .05) in CNP group. Histopathology of prostate revealed leucocyte infiltration, large involutions and projection into the lumen in CNP group and these aberrations were improved by PTX. According to these findings, we concluded that PTX effectively mitigated detrimental impact of CNP on sperm characteristics, reproductive hormones and histopathology in rats.

Evidence for a role of eosinophils in blister formation in bullous pemphigoid.

BACKGROUND: Bullous pemphigoid (BP) is an autoimmune bullous disease of the skin characterized by subepidermal blister formation due to tissue-bound and circulating autoantibodies to the hemidesmosomal antigens BP180 and BP230. Although eosinophils and their toxic mediators are found abundantly in BP lesions, their role in blister formation has remained unclear. OBJECTIVE: To investigate the role of eosinophils in the pathogenesis of BP with a specific focus on blister formation and to define conditions inducing dermal-epidermal separation (DES). METHODS: In an ex vivo human model of BP, normal human skin cryosections were incubated with purified human peripheral blood eosinophils with or without activation in the presence or absence of BP autoantibodies, brefeldin A, diphenyleneiodonium, DNase or blocking F(ab')2 fragments to CD16, CD18, CD32 and CD64. Dermal-epidermal separation was assessed by light microscopy studies and quantified using Fiji software. RESULTS: Following activation with IL-5 and in the presence of BP autoantibodies, eosinophils induced separation along the dermal-epidermal junction of ex vivo skin. Dermal-epidermal separation was significantly reduced by blocking any of the following: Fcγ receptor binding (P = 0.048), eosinophil adhesion (P = 0.046), reactive oxygen species (ROS) production (P = 0.002), degranulation (P < 0.0001) or eosinophil extracellular trap (EET) formation (P = 0.048). CONCLUSIONS: Our results provide evidence that IL-5-activated eosinophils directly contribute to BP blister formation in the presence of BP autoantibodies. Dermal-epidermal separation by IL-5-activated eosinophils depends on adhesion and Fcγ receptor activation, requires elevated ROS production and degranulation and involves EET formation. Thus, targeting eosinophils may be a promising therapeutic approach for BP.

Active eosinophilic esophagitis is characterized by epithelial barrier defects and eosinophil extracellular trap formation.

BACKGROUND: Eosinophilic esophagitis (EoE) exhibits esophageal dysfunction owing to an eosinophil-predominant inflammation. Activated eosinophils generate eosinophil extracellular traps (EETs) able to kill bacteria. There is evidence of an impaired barrier function in EoE that might allow pathogens to invade the esophagus. This study aimed to investigate the presence and distribution of EETs in esophageal tissues from EoE patients and their association with possible epithelial barrier defects. METHODS: Anonymized tissue samples from 18 patients with active EoE were analyzed. The presence of DNA nets associated with eosinophil granule proteins forming EETs and the expression of filaggrin, the protease inhibitor lympho-epithelial Kazal-type-related inhibitor (LEKTI), antimicrobial peptides, and cytokines were evaluated by confocal microscopy following immune fluorescence staining techniques. RESULTS: Eosinophil extracellular trap formation occurred frequently and was detected in all EoE samples correlating with the numbers of infiltrating eosinophils. While the expression of both filaggrin and LEKTI was reduced, epithelial antimicrobial peptides (human beta-defensin-2, human beta-defensin-3, cathelicidin LL-37, psoriasin) and cytokines (TSLP, IL-25, IL-32, IL-33) were elevated in EoE as compared to normal esophageal tissues. There was a significant correlation between EET formation and TSLP expression (P = 0.02) as well as psoriasin expression (P = 0.016). On the other hand, a significant negative correlation was found between EET formation and LEKTI expression (P = 0.016). CONCLUSION: Active EoE exhibits the presence of EETs. Indications of epithelial barrier defects in association with epithelial cytokines are also present which may have contributed to the activation of eosinophils. The formation of EETs could serve as a firewall against the invasion of pathogens.

Basophils exhibit antibacterial activity through extracellular trap formation.

Basophils are primarily associated with immunomodulatory functions in allergic diseases and parasitic infections. Recently, it has been demonstrated that both activated human and mouse basophils can form extracellular DNA traps (BETs) containing mitochondrial DNA and granule proteins. In this report, we provide evidence that, in spite of an apparent lack of phagocytic activity, basophils can kill bacteria through BET formation.

CFD convective flow simulation of the varying properties of CO2-H2O mixtures in geothermal systems.

Numerical simulation of a geothermal reservoir, modelled as a bottom-heated square box, filled with water-CO2 mixture is presented in this work. Furthermore, results for two limiting cases of a reservoir filled with either pure water or CO2 are presented. Effects of different parameters including CO2 concentration as well as reservoir pressure and temperature on the overall performance of the system are investigated. It has been noted that, with a fixed reservoir pressure and temperature, any increase in CO2 concentration leads to better performance, that is, stronger convection and higher heat transfer rates. With a fixed CO2 concentration, however, the reservoir pressure and temperature can significantly affect the overall heat transfer and flow rate from the reservoir. Details of such variations are documented and discussed in the present paper.

Extracellular DNA traps in allergic, infectious, and autoimmune diseases.

Extracellular DNA traps are part of the innate immune response and are seen with many infectious, allergic, and autoimmune diseases. They can be generated by several different leukocytes, including neutrophils, eosinophils, and monocytes, as well as mast cells. Here, we review the composition of these extracellular DNA-containing structures as well as potential mechanisms for their production and function. In general, extracellular DNA traps have been described as binding to and killing pathogens, particularly bacteria, fungi, but also parasites. On the other hand, it is possible that DNA traps contribute to immunopathology in chronic inflammatory diseases, such as bronchial asthma. In addition, it has been demonstrated that they can initiate and/or potentiate autoimmune diseases. Extracellular DNA traps represent a frequently observed phenomenon in inflammatory diseases, and they appear to participate in the cross-talk between different immune cells. These new insights into the pathogenesis of inflammatory diseases may open new avenues for targeted therapies.

Evaluating Similarity Measures for Brain Image Registration.

Evaluation of similarity measures for image registration is a challenging problem due to its complex interaction with the underlying optimization, regularization, image type and modality. We propose a single performance metric, named robustness, as part of a new evaluation method which quantifies the effectiveness of similarity measures for brain image registration while eliminating the effects of the other parts of the registration process. We show empirically that similarity measures with higher robustness are more effective in registering degraded images and are also more successful in performing intermodal image registration. Further, we introduce a new similarity measure, called normalized spatial mutual information, for 3D brain image registration whose robustness is shown to be much higher than the existing ones. Consequently, it tolerates greater image degradation and provides more consistent outcomes for intermodal brain image registration.

Thymic stromal lymphopoietin stimulates the formation of eosinophil extracellular traps.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) that is released by epithelial cells upon certain environmental triggers activates cells of the innate and adaptive immune system resulting in a preferential T helper 2 immune response. By releasing eosinophil extracellular traps (EETs), eosinophils achieve an efficient extracellular bacterial killing. Eosinophil extracellular traps release, however, has been observed in both infectious and noninfectious eosinophilic diseases. Here, we aim to investigate whether eosinophils generate functional EETs as a direct response to TSLP, and further to study the extra- and intracellular mechanisms involved in this process as well as TSLP receptor (TSLPR) expression by eosinophils in vitro and in vivo. METHODS: Thymic stromal lymphopoietin receptor expression on blood and tissue eosinophils was assessed by immunoblotting, flow cytometry, and immunofluorescence staining. Purified eosinophils were stimulated with recombinant human TSLP. The release of extracellular DNA in association with eosinophilic cationic protein (ECP) was detected by fluorescence staining techniques and confocal microscopy. In addition, cell survival, cell adhesion, production of reactive oxygen species (ROS), and the inhibition of bacterial growth by TSLP-stimulated eosinophils were measured. RESULTS: Thymic stromal lymphopoietin receptor was observed on peripheral blood eosinophils as well as on tissue infiltrating eosinophils in skin diseases. TSLP did not affect eosinophil survival, but induced the formation of EETs consisting of mitochondrial DNA in association with ECP in a concentration- and time-dependent manner. Eosinophil extracellular trap release could be inhibited by blocking either cell adhesion or ROS production. While eosinophils prevented the growth of both Staphylococcus aureus and Staphylococcus epidermidis, the latter were unable to elicit EET formation and eosinophils required additional TSLP stimulation to achieve this antibacterial activity. CONCLUSIONS: thymic stromal lymphopoietin directly stimulates eosinophils to produce EETs. Our observations link epithelial TSLP expression triggered by environmental factors with pathogen defense mechanisms involving eosinophils.

[Aneurysms of the deep femoral artery: a systematic review of literature]. / Aneurysma der A. profunda femoris - Eine systematische Literaturanalyse.

INTRODUCTION: True aneurysms of the deep femoral artery (APFA) are rare and are usually presented as case reports. Recommendations for diagnostics and therapy of APFAs are based on low-level evidence only. The purpose of this paper was to summarise the existing world experience with APFA. MATERIAL/METHODS: On the occasion of our own case a systematic review of the literature was performed for diagnostics and therapy for true APFA. Publications retrieved from PubMed, EMBASE, and the Cochrane Collaboration as well as by hand search from their references were reviewed. RESULTS: From 2002 onwards 25 papers on true APFAs were published in the English and German literature. Apart from two retrospective studies over a longer period of time these were exclusively case reports. A total of 55 true APFAs were reported in 47 patients with a mean age of 63 years. Therapeutic intervention was due to a rupture in 10 cases (18 %). The mean maximal diameter of APFA at presentation was 5.4 cm (2-18 cm). APFAs that were not ruptured presented frequently as a painful pulsatile mass in the groin and thigh. Therapeutic options for APFA included, apart from surgical resection with or without reconstruction of the deep femoral artery, the endovascular repair. DISCUSSION: Symptoms of swelling and pain in the presence of a mass at the proximal thigh should raise the suspicion of an APFA. Surgical therapy should be performed electively in APFAs with a diameter of more than 2 cm or in cases of rapid progression as well as in all symptomatic or ruptured cases. The endovascular approach should be considered as an alternative option in all cases.

Thrombus in the non-aneurysmal, non-atherosclerotic descending thoracic aorta--an unusual source of arterial embolism.

INTRODUCTION: Mural thrombus of the thoracic aorta is a rare clinical finding in the absence of aneurysm or atherosclerosis. METHODS: The medical records of all patients diagnosed with a thrombus of a non-aneurysmatic and non-atherosclerotic descending thoracic aorta (NAADTA) and treated by the senior author between 04/1997 and 04/2010 were reviewed. RESULTS: Eight patients with mural thrombus of the NAADTA were identified. Arterial embolism was the main clinical finding in all cases and involved the lower extremities (n = 6), mesenteric (n = 3) or renal arteries (n = 2). Hypercoagulable disorders were present in 3 cases and a concurrent malignancy in another 3. Two patients underwent open surgery while 4 patients were treated conservatively with anticoagulation. Of the remaining 2 patients, one was treated with a thoracic stent-graft and aorto-biiliac bypass and the other one with transfemoral thrombectomy. Technical success was achieved in all surgical cases and thrombus resolution or stable disease in the conservative management group. No thrombus recurrence was observed during a mean follow-up of 49 months. CONCLUSION: The management of mural thrombus in NAADTA represents a challenge, especially in case of malignant disease or hypercoagulable disorder as a potential underlying pathology and should be individualized. Although no consensus exists in the literature, therapeutic anticoagulation is proposed as first-line therapy. The indication for surgical intervention results from contraindication to anticoagulation, mobile thrombus or recurrent embolism. Whenever possible, endovascular therapy should be preferred.

Patterns of referral for fractured nose during major sporting events: a 10-year follow up.

INTRODUCTION: Nasal fracture is a common form of ear, nose and throat (ENT) trauma with prompt referral required for assessment and potentially manipulation of nasal bones. The aetiology of nasal fracture is multifactorial, and injury occurs across all ages. Previous study has suggested a temporal relationship between nasal injury and major sporting events. METHODS: A total of 1966 adult patients with nasal injuries referred to emergency clinics across three London ENT centres between September 2016 and August 2019 were analysed. RESULTS: The majority of those referred were male (66.58%). Mean age at referral was 36.29±18.38 in males and 49.14±21.43 in females; 10.27% were 75 years and over. Incidence was highest during April-September 2018 (p=0.02). Mean incidence was higher in this period in the male 16-35 subgroup (p=0.039), with 53.1% of their injuries concentrated between Friday and Sunday. CONCLUSIONS: Most nasal injuries occurred in young males. Mean age at referral was higher in females, and there was slightly increased incidence in over-75s, predominantly females. This incidence could be due to increased longevity or greater tendency to injury in females of this age. The injury patterns across the week also differed, with males injured proportionately more at the weekend. Nasal injury referrals of young men increased around the 2018 summer period, coinciding with the 2018 FIFA World Cup. This lends support to the association between major sporting events and the incidence of nasal injury, particularly in young males.

A systematic review of colorectal multidisciplinary team meetings: an international comparison.

BACKGROUND: Colorectal multidisciplinary teams (CR MDTs) were introduced to enhance the cancer care pathway and allow for early investigation and treatment of cancer. However, there are no 'gold standards' set for this process. The aim of this study was to review the literature systematically and provide a qualitative analysis on the principles, organization, structure and output of CR MDTs internationally. METHODS: Literature on the role of CR MDTs published between January 1999 and March 2020 in the UK, USA and continental Europe was evaluated. Historical background, structure, core members, education, frequency, patient-selection criteria, quality assurance, clinical output and outcomes were extracted from data from the UK, USA and continental Europe. RESULTS: Forty-eight studies were identified that specifically met the inclusion criteria. The majority of hospitals held CR MDTs at least fortnightly in the UK and Europe by 2002 and 2005 respectively. In the USA, monthly MDTs became a mandatory element of cancer programmes by 2013. In the UK, USA and in several European countries, the lead of the MDT meeting is a surgeon and core members include the oncologist, specialist nurse, histopathologist, radiologist and gastroenterologist. There were differences observed in patient-selection criteria, in the use of information technology, MDT databases and quality assurance internationally. CONCLUSION: CR MDTs are essential in improving the patient care pathway and should express clear recommendations for each patient. However, a form of quality assurance should be implemented across all MDTs.

Requirement of Lyn and Syk tyrosine kinases for the prevention of apoptosis by cytokines in human eosinophils.

In allergic diseases, the cytokines interleukin (IL)5 and granulocyte/macrophage colony-stimulating factor (GM-CSF) are upregulated and have been proposed to cause blood and tissue eosinophilia by inhibition of eosinophil apoptosis. We demonstrate herein, in freshly isolated human eosinophils, that the IL-3/IL-5/GM-CSF receptor beta subunit interacts with cytoplasmic tyrosine kinases to induce phosphorylation of several cellular substrates, including the beta subunit itself. The Lyn and Syk intracellular tyrosine kinases constitutively associate at a low level with the IL-3/IL-5/GM-CSF receptor beta subunit in human eosinophils. Stimulation with GM-CSF or IL-5 results in a rapid and transient increase in the amount of Lyn and Syk associated with the IL-3/IL-5/GM-CSF receptor beta subunit. Lyn is required for optimal tyrosine phosphorylation and activation of Syk. In contrast, Syk is not required for optimal tyrosine phosphorylation and activation of Lyn. These data suggest that Lyn is proximal to Syk in a tyrosine kinase cascade that transduces IL-3, IL-5, or GM-CSF signals. Compatible with this model, both Lyn and Syk are essential for the activation of the antiapoptotic pathway(s) induced through the IL-3/IL-5/GM-CSF receptor beta subunit in human eosinophils.

Platelet-activating factor exerts mitogenic activity and stimulates expression of interleukin 6 and interleukin 8 in human lung fibroblasts via binding to its functional receptor.

Platelet-activating factor (PAF) is a potent proinflammatory phospholipid mediator of the lung. In this study, we demonstrate that PAF receptor mRNA and protein is expressed by human lung fibroblasts. Interaction of PAF with its specific receptor resulted in increases of tyrosine phosphorylation of several intracellular proteins, indicating that the PAF-receptor might be functionally active. PAF-induced transcription of protooncogenes c-fos and c-jun as well as of interleukin (IL)-6 and IL-8 genes in human fibroblasts. Transcription of the interleukins was followed by secretion of the respective proteins. Moreover, PAF enhanced proliferation of fibroblasts in a concentration-dependent manner. Using signaling inhibitors, we demonstrate that PAF-induced transcription of the c-fos, IL-6, and IL-8 genes, as well as proliferation, require activation of pertussis toxin-sensitive G proteins, tyrosine kinases, and protein kinase C (PKC). In contrast, transcription of c-jun was blocked by pertussis toxin, but not by inhibitors for tyrosine kinases or PKC. These data suggest that PAF stimulates distinct signaling pathways in human lung fibroblasts. In addition, the activation of human fibroblasts by PAF leads to enhanced proliferation and to the expression of proinflammatory cytokines, which may contribute to the pathophysiological changes in pulmonary inflammation.

Expansion of cytokine-producing CD4-CD8- T cells associated with abnormal Fas expression and hypereosinophilia.

The mechanisms of sustained overproduction of eosinophils in the idiopathic hypereosinophilic syndrome and in some human immunodeficiency virus (HIV)-1-infected individuals are largely unknown. We hypothesized that T cells may release soluble products that regulate eosinophilia in these patients, as has been previously shown in bronchial asthma. We identified one patient with idiopathic hypereosinophilic syndrome and one HIV-1-infected individual with associated hypereosinophilia who demonstrated high numbers of CD4-CD8- T cells in peripheral blood. CD4-CD8- T cells from both patients, although highly activated, did not express functional Fas receptors. In one case, the lack of functional Fas receptors was associated with failure of Fas mRNA and protein expression, and in another, expression of a soluble form of the Fas molecule that may have antagonized normal signaling of Fas ligand. In contrast to the recently described lymphoproliferative/autoimmune syndrome, which is characterized by accumulation of CD4-CD8- T cells and mutations within the Fas gene, this study suggests somatic variations in Fas expression and function quite late in life. Both genetic and somatic abnormalities in regulation of the Fas gene are therefore associated with failures to undergo T cell apoptosis. Furthermore, the expanded population of CD4-CD8- T cells from both patients elaborated cytokines with antiapoptotic properties for eosinophils, indicating a major role of these T cells in the development of eosinophilia. Thus, this study demonstrates a sequential dysregulation of apoptosis in different cell types.

Neutrophil apoptosis mediated by nicotinic acid receptors (GPR109A).

G protein-coupled receptor (GPR)109A (HM74A) is a G(i) protein-coupled receptor, which is activated by nicotinic acid (NA), a lipid-lowering drug. Here, we demonstrate that mature human neutrophils, but not eosinophils, express functional GPR109A receptors. The induction of the GPR109A gene appears to occur late in the terminal differentiation process of neutrophils, since a mixed population of immature bone marrow neutrophils did not demonstrate evidence for its expression. NA accelerated apoptosis in cultured neutrophils in a concentration-dependent manner, as assessed by phosphatidylserine redistribution, caspase-3 activation, and DNA fragmentation assays. The pro-apoptotic effect of NA was abolished by pertussis toxin, which was used to block G(i) proteins, suggesting a receptor-mediated mechanism. Activation of GPR109A by NA resulted in decreased levels of cyclic adenosine monophosphate (cAMP), most likely due to G(i)-mediated inhibition of adenylyl cyclase activity. NA-induced apoptosis was reversed by the addition of cell-permeable cAMP, pointing to the possibility that reduced cAMP levels promote apoptosis in neutrophils. Distal mechanism involved in this process may include the post-translational modification of members of the Bcl-2 family, such as dephosphorylation of pro-apoptotic Bad and antiapoptotic Mcl-1 proteins. Taken together, following maturation in the bone marrow, neutrophils express functional GPR109A receptors, which might be involved in the regulation of neutrophil numbers. Moreover, this study identified a new cellular target of NA and future drugs activating GPR109A receptors, the mature neutrophil.

A novel FIP1L1-PDGFRA mutant destabilizing the inactive conformation of the kinase domain in chronic eosinophilic leukemia/hypereosinophilic syndrome.

BACKGROUND: The Fip1-like-1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) gene fusion is a common cause of chronic eosinophilic leukemia (CEL)/hypereosinophilic syndrome (HES), and patients suffering from this particular subgroup of CEL/HES respond to low-dose imatinib therapy. However, some patients may develop imatinib resistance because of an acquired T674I mutation, which is believed to prevent drug binding through steric hindrance. METHODS: In an imatinib resistant FIP1L1-PDGFRA positive patient, we analyzed the molecular structure of the fusion gene and analyzed the effect of several kinase inhibitors on FIP1L1-PDGFRA-mediated proliferative responses in vitro. RESULTS: Sequencing of the FIP1L1-PDGFRA fusion gene revealed the occurrence of a S601P mutation, which is located within the nucleotide binding loop. In agreement with the clinical observations, imatinib did not inhibit the proliferation of S601P mutant FIP1L1-PDGFRA-transduced Ba/F3 cells. Moreover, sorafenib, which has been described to inhibit T674I mutant FIP1L1-PDGFRA, failed to block S601P mutant FIP1L1-PDGFRA. Structural modeling revealed that the newly identified S601P mutated form of PDGFRA destabilizes the inactive conformation of the kinase domain that is necessary to bind imatinib as well as sorafenib. CONCLUSIONS: We identified a novel mutation in FIP1L1-PDGFRA resulting in both imatinib and sorafenib resistance. The identification of novel drug-resistant FIP1L1-PDGFRA variants may help to develop the next generation of target-directed compounds for CEL/HES and other leukemias.