Does the COVID-19 personal protective equipment impair the surgeon's performance?

INTRODUCTION: Despite increasing vaccination rates, new viral variants of SARS-CoV-2 (severe acute respiratory syndrome coronavirus type 2) are advancing the COVID 19 (coronavirus disease 2019) pandemic and continue to challenge the entire world. Surgical care of SARS-CoV-2 positive patients requires special protective measures. We hypothesized that "COVID-19" personal protective equipment (PPE) during surgery of SARS-CoV-2 positive or potentially positive patients would negatively affect the surgeon and thus the surgical outcome. MATERIALS AND METHODS: Ten experienced trauma surgeons participated in the study. Each surgeon performed two simulated surgeries of a distal tibial fracture on a Sawbone® under standardized conditions either wearing regular PPE or special COVID-19 PPE. Baseline values at rest were acquired for heart rate, blood pressure, saturation of peripheral oxygen (SpO2), respiratory rate and capillary blood gas (CBG) analysis including capillary partial pressure of oxygen (pO2) and carbon dioxide (pCO2), followed by four different standardized tests of attentional performance (TAP). Subsequently, the surgeon performed the first surgery according to a randomly determined order, with regular or COVID-19 PPE conditions in an operation theatre. After each surgery vital signs were acquired and CBG and TAP were performed again. RESULTS: In our simulated surgical procedure heart rate, respiratory rate, systolic and diastolic blood pressure did not show relevant differences. Percutaneously measured SpO2 decreased with additional layers of PPE, while CBG parameters were not affected. TAP tests showed a significant impairment of attention if PPEs were compared to the baseline, but both PPEs had similar results and no meaningful differences could be measured. CONCLUSIONS: According to our results, for surgical procedures additional PPE required during COVID-19 pandemic does not relevant affect the surgeon's mental and physical performance. Surgeries under COVID-19 PPE conditions appear safe and do not increase patient risk. LEVEL OF EVIDENCE: Level I.

Efferocytosis fuels malignant pleural effusion through TIMP1.

Malignant pleural effusion (MPE) results from the capacity of several human cancers to metastasize to the pleural cavity. No effective treatments are currently available, reflecting our insufficient understanding of the basic mechanisms leading to MPE progression. Here, we found that efferocytosis through the receptor tyrosine kinases AXL and MERTK led to the production of interleukin-10 (IL-10) by four distinct pleural cavity macrophage (Mφ) subpopulations characterized by different metabolic states and cell chemotaxis properties. In turn, IL-10 acts on dendritic cells (DCs) inducing the production of tissue inhibitor of metalloproteinases 1 (TIMP1). Genetic ablation of Axl and Mertk in Mφs or IL-10 receptor in DCs or Timp1 substantially reduced MPE progression. Our results delineate an inflammatory cascade-from the clearance of apoptotic cells by Mφs, to production of IL-10, to induction of TIMP1 in DCs-that facilitates MPE progression. This inflammatory cascade offers a series of therapeutic targets for MPE.

Inactivation of Adeno-Associated Viral Vectors by Oxidant-Based Disinfectants.

Adeno-associated viral (AAV) vectors are becoming increasingly popular in basic research as well as in clinical gene therapy. Due to its exceptional resistance against physical and chemical stress, however, the increasing use of AAV in laboratories and clinics around the globe raises safety concerns. Proper decontamination of tools and surfaces based on reliable AAV inactivation is crucial to prevent uncontrolled vector dissemination. Although recommended for AAV decontamination, sodium hypochlorite is not compatible with all surfaces found in the laboratory or clinical environment due to its corrosive nature. We, therefore, compared 0.5% sodium hypochlorite to 0.25% peracetic acid (PAA), a second substance declared effective, and to three less aggressive, commonly available alternative disinfectants 70% ethanol, 1.5% hydrogen peroxide, and 0.45% potassium peroxymonosulfate. The impact of all five disinfectants on virus capsid integrity, viral genome integrity, and infectivity upon different exposure times was tested on AAV2 and AAV5, two serotypes with highly different thermostability. While sodium hypochlorite, potassium peroxymonosulfate, and PAA successfully inactivated AAV2 after 1, 5, and 30 min, respectively, ethanol and hydrogen peroxide did not show significant effects on AAV2 even after exposure for 30 min. For AAV5, only sodium hypochlorite and potassium peroxymonosulfate proved efficient capsid and genome denaturation after incubation for 1 and 30 min, respectively. Consequently, ethanol or hydrogen peroxide should not be considered for routine laboratory or clinical use, while 0.45% potassium peroxymonosulfate and 0.5% sodium hypochlorite represent suitable and broadly effective disinfectants for AAV inactivation.

PPARγ-p53-Mediated Vasculoregenerative Program to Reverse Pulmonary Hypertension.

RATIONALE: In pulmonary arterial hypertension (PAH), endothelial dysfunction and obliterative vascular disease are associated with DNA damage and impaired signaling of BMPR2 (bone morphogenetic protein type 2 receptor) via two downstream transcription factors, PPARγ (peroxisome proliferator-activated receptor gamma), and p53. OBJECTIVE: We investigated the vasculoprotective and regenerative potential of a newly identified PPARγ-p53 transcription factor complex in the pulmonary endothelium. METHODS AND RESULTS: In this study, we identified a pharmacologically inducible vasculoprotective mechanism in pulmonary arterial and lung MV (microvascular) endothelial cells in response to DNA damage and oxidant stress regulated in part by a BMPR2 dependent transcription factor complex between PPARγ and p53. Chromatin immunoprecipitation sequencing and RNA-sequencing established an inducible PPARγ-p53 mediated regenerative program regulating 19 genes involved in lung endothelial cell survival, angiogenesis and DNA repair including, EPHA2 (ephrin type-A receptor 2), FHL2 (four and a half LIM domains protein 2), JAG1 (jagged 1), SULF2 (extracellular sulfatase Sulf-2), and TIGAR (TP53-inducible glycolysis and apoptosis regulator). Expression of these genes was partially impaired when the PPARγ-p53 complex was pharmacologically disrupted or when BMPR2 was reduced in pulmonary artery endothelial cells (PAECs) subjected to oxidative stress. In endothelial cell-specific Bmpr2-knockout mice unable to stabilize p53 in endothelial cells under oxidative stress, Nutlin-3 rescued endothelial p53 and PPARγ-p53 complex formation and induced target genes, such as APLN (apelin) and JAG1, to regenerate pulmonary microvessels and reverse pulmonary hypertension. In PAECs from BMPR2 mutant PAH patients, pharmacological induction of p53 and PPARγ-p53 genes repaired damaged DNA utilizing genes from the nucleotide excision repair pathway without provoking PAEC apoptosis. CONCLUSIONS: We identified a novel therapeutic strategy that activates a vasculoprotective gene regulation program in PAECs downstream of dysfunctional BMPR2 to rehabilitate PAH PAECs, regenerate pulmonary microvessels, and reverse disease. Our studies pave the way for p53-based vasculoregenerative therapies for PAH by extending the therapeutic focus to PAEC dysfunction and to DNA damage associated with PAH progression.

Subcellular Compartmentalization of Survivin is Associated with Biological Aggressiveness and Prognosis in Prostate Cancer.

The role of subcellular survivin compartmentalization in the biology and prognosis of prostate cancer is unclear. We therefore investigated subcellular localization of survivin in more than 3000 prostate cancer patients by quantitative immunohistochemistry and performed transcriptomics of 250 prostate cancer patients and healthy donors using publicly available datasets. Survivin (BIRC5) gene expression was increased in primary prostate cancers and metastases, but did not differ in recurrent vs non-recurrent prostate cancers. Survivin immunohistochemistry (IHC) staining was limited exclusively to the nucleus in 900 prostate cancers (40.0%), and accompanied by various levels of cytoplasmic positivity in 1338 tumors (59.4%). 0.5% of prostate cancers did not express survivin. Nuclear and cytoplasmic survivin staining intensities were strongly associated with each other, pT category, and higher Gleason scores. Cytoplasmic but not nuclear survivin staining correlated with high tumor cell proliferation in prostate cancers. Strong cytoplasmic survivin staining, but not nuclear staining predicted an unfavorable outcome in univariate analyses. Multivariate Cox regression analysis showed that survivin is not an independent prognostic marker. In conclusion, we provide evidence that survivin expression is increased in prostate cancers, especially in metastatic disease, resulting in higher aggressiveness and tumor progression. In addition, subcellular compartmentalization is an important aspect of survivin cancer biology, as only cytoplasmic, but not nuclear survivin accumulation is linked to biological aggressiveness and prognosis of prostate cancers.

The Actin Binding Protein Plastin-3 Is Involved in the Pathogenesis of Acute Myeloid Leukemia.

Leukemia-initiating cells reside within the bone marrow in specialized niches where they undergo complex interactions with their surrounding stromal cells. We have identified the actin-binding protein Plastin-3 (PLS3) as potential player within the leukemic bone marrow niche and investigated its functional role in acute myeloid leukemia. High expression of PLS3 was associated with a poor overall and event-free survival for AML patients. These findings were supported by functional in vitro and in vivo experiments. AML cells with a PLS3 knockdown showed significantly reduced colony numbers in vitro while the PLS3 overexpression variants resulted in significantly enhanced colony numbers compared to their respective controls. Furthermore, the survival of NSG mice transplanted with the PLS3 knockdown cells showed a significantly prolonged survival in comparison to mice transplanted with the control AML cells. Further studies should focus on the underlying leukemia-promoting mechanisms and investigate PLS3 as therapeutic target.

Upregulation of Human Endogenous Retrovirus-K Is Linked to Immunity and Inflammation in Pulmonary Arterial Hypertension.

BACKGROUND: Immune dysregulation has been linked to occlusive vascular remodeling in pulmonary arterial hypertension (PAH) that is hereditary, idiopathic, or associated with other conditions. Circulating autoantibodies, lung perivascular lymphoid tissue, and elevated cytokines have been related to PAH pathogenesis but without a clear understanding of how these abnormalities are initiated, perpetuated, and connected in the progression of disease. We therefore set out to identify specific target antigens in PAH lung immune complexes as a starting point toward resolving these issues to better inform future application of immunomodulatory therapies. METHODS: Lung immune complexes were isolated and PAH target antigens were identified by liquid chromatography tandem mass spectrometry, confirmed by enzyme-linked immunosorbent assay, and localized by confocal microscopy. One PAH antigen linked to immunity and inflammation was pursued and a link to PAH pathophysiology was investigated by next-generation sequencing, functional studies in cultured monocytes and endothelial cells, and hemodynamic and lung studies in a rat. RESULTS: SAM domain and HD domain-containing protein 1 (SAMHD1), an innate immune factor that suppresses HIV replication, was identified and confirmed as highly expressed in immune complexes from 16 hereditary and idiopathic PAH versus 12 control lungs. Elevated SAMHD1 was localized to endothelial cells, perivascular dendritic cells, and macrophages, and SAMHD1 antibodies were prevalent in tertiary lymphoid tissue. An unbiased screen using metagenomic sequencing related SAMHD1 to increased expression of human endogenous retrovirus K (HERV-K) in PAH versus control lungs (n=4). HERV-K envelope and deoxyuridine triphosphate nucleotidohydrolase mRNAs were elevated in PAH versus control lungs (n=10), and proteins were localized to macrophages. HERV-K deoxyuridine triphosphate nucleotidohydrolase induced SAMHD1 and proinflammatory cytokines (eg, interleukin 6, interleukin 1ß, and tumor necrosis factor α) in circulating monocytes, pulmonary arterial endothelial cells, and also activated B cells. Vulnerability of pulmonary arterial endothelial cells (PAEC) to apoptosis was increased by HERV-K deoxyuridine triphosphate nucleotidohydrolase in an interleukin 6-independent manner. Furthermore, 3 weekly injections of HERV-K deoxyuridine triphosphate nucleotidohydrolase induced hemodynamic and vascular changes of pulmonary hypertension in rats (n=8) and elevated interleukin 6. CONCLUSIONS: Our study reveals that upregulation of the endogenous retrovirus HERV-K could both initiate and sustain activation of the immune system and cause vascular changes associated with PAH.

Amphetamines promote mitochondrial dysfunction and DNA damage in pulmonary hypertension.

Amphetamine (AMPH) or methamphetamine (METH) abuse can cause oxidative damage and is a risk factor for diseases including pulmonary arterial hypertension (PAH). Pulmonary artery endothelial cells (PAECs) from AMPH-associated-PAH patients show DNA damage as judged by γH2AX foci and DNA comet tails. We therefore hypothesized that AMPH induces DNA damage and vascular pathology by interfering with normal adaptation to an environmental perturbation causing oxidative stress. Consistent with this, we found that AMPH alone does not cause DNA damage in normoxic PAECs, but greatly amplifies DNA damage in hypoxic PAECs. The mechanism involves AMPH activation of protein phosphatase 2A, which potentiates inhibition of Akt. This increases sirtuin 1, causing deacetylation and degradation of HIF1α, thereby impairing its transcriptional activity, resulting in a reduction in pyruvate dehydrogenase kinase 1 and impaired cytochrome c oxidase 4 isoform switch. Mitochondrial oxidative phosphorylation is inappropriately enhanced and, as a result of impaired electron transport and mitochondrial ROS increase, caspase-3 is activated and DNA damage is induced. In mice given binge doses of METH followed by hypoxia, HIF1α is suppressed and pulmonary artery DNA damage foci are associated with worse pulmonary vascular remodeling. Thus, chronic AMPH/METH can induce DNA damage associated with vascular disease by subverting the adaptive responses to oxidative stress.

Acute effects of exercise on the inflammatory state in patients with idiopathic pulmonary arterial hypertension.

BACKGROUND: Exercise training positively influences exercise tolerance and functional capacity of patients with idiopathic pulmonary arterial hypertension (IPAH). However, the underlying mechanisms are unclear. We hypothesized that exercise modulates the activated inflammatory state found in IPAH patients. METHODS: Single cardiopulmonary exercise testing was performed in 16 IPAH patients and 10 healthy subjects. Phenotypic characterization of peripheral blood mononuclear cells and circulating cytokines were assessed before, directly after and 1 h after exercise. RESULTS: Before exercise testing, IPAH patients showed elevated Th2 lymphocytes, regulatory T lymphocytes, IL-6, and TNF-alpha, whilst Th1/Th17 lymphocytes and IL-4 were reduced. In IPAH patients but not in healthy subject, exercise caused an immediate relative decrease of Th17 lymphocytes and a sustained reduction of IL-1-beta and IL-6. The higher the decrease of IL-6 the higher was the peak oxygen consumption of IPAH patients. CONCLUSIONS: Exercise seems to be safe from an immune and inflammatory point of view in IPAH patients. Our results demonstrate that exercise does not aggravate the inflammatory state and seems to elicit an immune-modulating effect in IPAH patients.

In Pulmonary Arterial Hypertension, Reduced BMPR2 Promotes Endothelial-to-Mesenchymal Transition via HMGA1 and Its Target Slug.

BACKGROUND: We previously reported high-throughput RNA sequencing analyses that identified heightened expression of the chromatin architectural factor High Mobility Group AT-hook 1 (HMGA1) in pulmonary arterial endothelial cells (PAECs) from patients who had idiopathic pulmonary arterial hypertension (PAH) in comparison with controls. Because HMGA1 promotes epithelial-to-mesenchymal transition in cancer, we hypothesized that increased HMGA1 could induce transition of PAECs to a smooth muscle (SM)-like mesenchymal phenotype (endothelial-to-mesenchymal transition), explaining both dysregulation of PAEC function and possible cellular contribution to the occlusive remodeling that characterizes advanced idiopathic PAH. METHODS AND RESULTS: We documented increased HMGA1 in PAECs cultured from idiopathic PAH versus donor control lungs. Confocal microscopy of lung explants localized the increase in HMGA1 consistently to pulmonary arterial endothelium, and identified many cells double-positive for HMGA1 and SM22α in occlusive and plexogenic lesions. Because decreased expression and function of bone morphogenetic protein receptor 2 (BMPR2) is observed in PAH, we reduced BMPR2 by small interfering RNA in control PAECs and documented an increase in HMGA1 protein. Consistent with transition of PAECs by HMGA1, we detected reduced platelet endothelial cell adhesion molecule 1 (CD31) and increased endothelial-to-mesenchymal transition markers, αSM actin, SM22α, calponin, phospho-vimentin, and Slug. The transition was associated with spindle SM-like morphology, and the increase in αSM actin was largely reversed by joint knockdown of BMPR2 and HMGA1 or Slug. Pulmonary endothelial cells from mice with endothelial cell-specific loss of Bmpr2 showed similar gene and protein changes. CONCLUSIONS: Increased HMGA1 in PAECs resulting from dysfunctional BMPR2 signaling can transition endothelium to SM-like cells associated with PAH.

Transcription Factor Runx2 Promotes Aortic Fibrosis and Stiffness in Type 2 Diabetes Mellitus.

RATIONALE: Accelerated arterial stiffening is a major complication of diabetes mellitus with no specific therapy available to date. OBJECTIVE: The present study investigates the role of the osteogenic transcription factor runt-related transcription factor 2 (Runx2) as a potential mediator and therapeutic target of aortic fibrosis and aortic stiffening in diabetes mellitus. METHODS AND RESULTS: Using a murine model of type 2 diabetes mellitus (db/db mice), we identify progressive structural aortic stiffening that precedes the onset of arterial hypertension. At the same time, Runx2 is aberrantly upregulated in the medial layer of db/db aortae, as well as in thoracic aortic samples from patients with type 2 diabetes mellitus. Vascular smooth muscle cell-specific overexpression of Runx2 in transgenic mice increases expression of its target genes, Col1a1 and Col1a2, leading to medial fibrosis and aortic stiffening. Interestingly, increased Runx2 expression per se is not sufficient to induce aortic calcification. Using in vivo and in vitro approaches, we further demonstrate that expression of Runx2 in diabetes mellitus is regulated via a redox-sensitive pathway that involves a direct interaction of NF-κB with the Runx2 promoter. CONCLUSIONS: In conclusion, this study highlights Runx2 as a previously unrecognized inducer of vascular fibrosis in the setting of diabetes mellitus, promoting arterial stiffness irrespective of calcification.

Loss of somatostatin receptor subtype 2 in prostate cancer is linked to an aggressive cancer phenotype, high tumor cell proliferation and predicts early metastatic and biochemical relapse.

Somatostatin receptor subtype 2 (SSTR2) is the most frequently expressed SSTR subtype in normal human tissues. SSTR2 expression is differentially regulated in various tumor types and therapeutic somatostatin analogs binding to SSTR2 are in clinical use. In prostate cancers highly contradictory results in terms of SSTR2 expression and its consequences have been published over the past years. The aim of this study was to clarify prevalence and clinical significance of SSTR2 expression in prostate cancer. Therefore, quantitative immunohistochemistry (IHC) using a tissue microarray containing samples from 3,261 prostate cancer patients with extensive clinical and molecular cancer characteristics and oncological follow-up data was performed. IHC data was compared to publicly available Gene Expression Omnibus datasets of human prostate cancer gene expression arrays. While membranous SSTR2 staining was always seen in normal prostate epithelium, SSTR2 staining was absent in more than half (56.1%) of 2,195 interpretable prostate cancer samples. About 13% of all analyzed prostate cancers showed moderate to strong cytoplasmic and membranous SSTR2 staining. Staining intensities were inversely correlated with high Gleason grade, advanced pT category, high tumor cell proliferation (p<0.0001 each), high pre-operative PSA levels, (p = 0.0011) and positive surgical margins (p = 0.006). In silico analysis confirmed lower SSTR2 gene expression in prostate cancers vs. normal adjacent tissue (p = 0.0424), prostate cancer metastases vs. primary cancers (p = 0.0011) and recurrent vs. non-recurrent prostate cancers (p = 0.0438). PSA-free survival gradually declined with SSTR2 staining intensity (p<0.0001). SSTR2-negative cancers were more likely to develop metastases over time (p<0.05). In conclusion, most prostate cancers are indeed SSTR2-negative and loss of SSTR2 strongly predicts an unfavorable tumor phenotype and poor prognosis. Therefore, SSTR2 expression seems an important factor in the pathogenesis of prostate cancer and re-introduction of the receptor in SSTR2-negative prostate cancers may feature a promising target for novel gene therapy approaches.

The endothelial ADMA/NO pathway in hypoxia-related chronic respiratory diseases.

Since its discovery, many adhere to the view that asymmetric dimethylarginine (ADMA), as an inhibitor of the synthesis of nitric oxide (NO), contributes to the pathogenesis of various diseases. Particularly, this is evident in disease of the cardiovascular system, in which endothelial dysfunction results in an imbalance between vasoconstriction and vasodilatation. Even if increased ADMA concentrations are closely related to an endothelial dysfunction, several studies pointed to a potential beneficial effect of ADMA, mainly in the context of angioproliferative disease such as cancer and fibrosis. Antiproliferative properties of ADMA independent of NO have been identified in this context. In particular, the regulation of ADMA by its degrading enzyme dimethylarginine dimethylaminohydrolase (DDAH) is the object of many studies. DDAH is discussed as a promising therapeutic target for the indirect regulation of NO. In hypoxia-related chronic respiratory diseases, this controversy discussion of ADMA and DDAH is particularly evident and is therefore subject of this review.

Fiber optic bronchoscopy in patients with acute hypoxemic respiratory failure requiring noninvasive ventilation--a feasibility study.

INTRODUCTION: Noninvasive ventilation (NIV) is a standard procedure in selected patients with acute respiratory failure. Previous studies have used noninvasive ventilation to ensure adequate gas exchange during fiberoptic bronchoscopy in spontaneously breathing hypoxemic patients, thus avoiding endotracheal intubation. However, it is unknown whether bronchoscopy can be performed safely in patients with acute hypoxemic respiratory failure already in need of NIV prior to the decision for bronchoscopy. METHODS: We prospectively investigated 40 consecutive, critically ill, adult patients with acute hypoxemic respiratory failure (14 women, 26 men, age 61 ± 15 years, partial pressure for oxygen/fraction of inspired oxygen (PaO2/FiO2) < 300 under noninvasive ventilation, Simplified Acute Physiology scores (SAPS II) 47 ± 9.9 points). All patients required noninvasive ventilation prior to the decision to perform bronchoscopy (median 10.5 h; range 2.2 to 114). Blood gases, heart rate, blood pressure and ventilation were monitored before, during and up to 120 minutes after bronchoscopy. RESULTS: Bronchoscopy could be completed in all patients without subsequent complications. Oxygen saturation fell to < 90% in two patients (5%), and the lowest value during the procedure was 84%. The mean PaO2/FiO2 ratio improved from 176 ± 54 at baseline to 240 ± 130 (P < 0.001) at the end of bronchoscopy and 210 ± 79 after 120 minutes. The transient mean partial pressure of carbon dioxide in the arterial blood (PaCO2) increase was 9.4 ± 8.1 mm Hg. Four patients (10%) required endotracheal intubation during the first eight hours after the procedure. Bronchoalveolar lavage yielded diagnostic information in 26 of 38 (68%) patients. CONCLUSIONS: In critically ill patients with acute hypoxemic respiratory failure requiring noninvasive ventilation, bronchoscopy can be performed with an acceptable risk. Since these patients per se have a high likelihood of subsequent endotracheal intubation due to failure of NIV, bronchoscopy should only be performed by experienced clinicians.

Molecular basis of P2-receptor-mediated calcium signaling in activated pancreatic stellate cells.

OBJECTIVES: There is growing evidence that extracellular nucleotide-induced signaling confers to fibrogenesis in liver and pancreas. Pancreatic stellate cells (PSC) are the most important cell type in pancreatic fibrosis. P2 purine and pyrimidine receptors, again, are pivotal mediators of inflammatory and profibrogenic signals. Our aim was to elucidate the underlying signaling components in activated PSC. METHODS: We performed expression analysis of calcium ion (Ca(2+)) signaling components and monitored real-time intracellular Ca(2+) responses to nucleotides in rat PSC. RESULTS: Adenosine monophosphate, adenosine diphosphate, and adenosine-5'-triphosphate elicited detectable rises in intracellular Ca(2+) concentrations. Stimulation of PSC by ATP led to intracellular Ca signals mediated through both P2X and P2Y receptors. Whereas uridine triphosphate-mediated Ca(2+) signals were generated by activation of P2Y receptors only, uridine diphosphate stimulated P2X receptors as well. Of the phospholipase C (PLC)/inositol-1,4,5-trisphosphate pathway, all PLC-facilitating Gα subunits were present in activated cells as were all 3 inositol-1,4,5-trisphosphate receptor isoforms. In addition, transcripts of PLC-ß and PLC-δ isoforms were also strongly detectable. CONCLUSIONS: Activated PSC feature a plethora of elements from the Ca signaling toolkit and functionally express a subset of P2 nucleotide receptors. Purines and pyrimidines elicit robust intracellular Ca(2+) signals likely contributing to the fibrogenetic potential of these cells.

Multi tyrosine kinase inhibitor dasatinib as novel cause of severe pre-capillary pulmonary hypertension?

BACKGROUND: Pulmonary hypertension (PH) is a life-threatening disease with poor prognosis. Encouraging efforts have been made to target the main vasoproliferative aspects of the disease. Promising emerging therapeutics are tyrosine kinase inhibitors such as imatinib. CASE PRESENTATION: Here, we discuss the relevance of previously published cases and add another well-characterised patient who developed pre-capillary PH under long-term therapy with the multi-tyrosine kinase inhibitor dasatinib approved for therapy of chronic myeloic leukaemia (CML) and Philadelphia chromosome positive acute lymphocytic leukaemia (mean time of all patients on dasatinib: 26 months). Hence, we discuss the possibility of dasatinib itself causing PH after long-term therapy and turn specialist's attention to this possible severe side effect.At present, the true incidence of dasatinib-associated PH remains illusive and systematic data regarding haemodynamics are missing. CONCLUSION: We therefore recommend systematic screening of dasatinib-treated patients for pulmonary hypertension and subsequent collection of haemodynamic data.

Sweet taste receptor interacting protein CIB1 is a general inhibitor of InsP3-dependent Ca2+ release in vivo.

In a search for sweet taste receptor interacting proteins, we have identified the calcium- and integrin-binding protein 1 (CIB1) as specific binding partner of the intracellular carboxyterminal domain of the rat sweet taste receptor subunit Tas1r2. In heterologous human embryonic kidney 293 (HEK293) cells, the G protein chimeras Galpha(16gust44) and Galpha(15i3) link the sweet taste receptor dimer TAS1R2/TAS1R3 to an inositol 1,4,5-trisphosphate (InsP3)-dependent Ca2+ release pathway. To demonstrate the influence of CIB1 on the cytosolic Ca2+ concentration, we used sweet and umami compounds as well as other InsP3-generating ligands in FURA-2-based Ca2+ assays in wild-type HEK293 cells and HEK293 cells expressing functional human sweet and umami taste receptor dimers. Stable and transient depletion of CIB1 by short-hairpin RNA increased the Ca2+ response of HEK293 cells to the InsP3-generating ligands ATP, UTP and carbachol. Over-expression of CIB1 had the opposite effect as shown for the sweet ligand saccharin, the umami receptor ligand monosodium glutamate and UTP. The CIB1 effect was dependent on the thapsigargin-sensitive Ca2+ store of the endoplasmic reticulum (ER) and independent of extracellular Ca2+. The function of CIB1 on InsP3-evoked Ca2+ release from the ER is most likely mediated by its interaction with the InsP3 receptor. Thus, CIB1 seems to be an inhibitor of InsP3-dependent Ca2+ release in vivo.