Feasibility and Safety of Bridging Antiplatelet Therapy with Cangrelor in Neuro-Oncology: A Preliminary Experience.

Antiplatelet therapy is mandatory for prevention of thrombotic events in patients with a recent history of acute coronary syndromes and/or percutaneous coronary interventions. However, if an urgent surgery is required during antiplatelet therapy, a compromise between the ischemic/thrombotic and hemorrhagic risk has to be reached. Different bridging schemes are reported in the literature, but there is no clear consensus on the optimal treatment strategy in terms of efficacy and safety. Although some indications about the perioperative management of antiplatelet therapy regarding specific surgical specializations are available, balancing the thrombotic and hemorrhagic risk on an individual basis, no evidence referring to neurosurgical or neuro-oncologic procedures is reported. Herein, we present our preliminary experience in the perioperative management of a patient who underwent a neurosurgical procedure for the resection of a primary malignant brain tumor using an intravenous P2Y12 inhibitor (cangrelor) as bridging therapy after a recent acute myocardial infarction treated with primary percutaneous coronary intervention and stenting. The oral P2Y12 inhibitor (clopidogrel) was withdrawn 5 days prior to the surgical procedure and continuous infusion of cangrelor was started 3 days before the surgery at a dose of 0.75 µg/kg/min. Cangrelor was discontinued 2 hours before surgery and resumed 72 hours after tumor resection for further 60 hours. Neither cangrelor-related bleeding nor cardiac ischemic events were observed in the perioperative period and the following 90 days, supporting data regarding the feasibility and safety of this bridging scheme. Further studies are needed to confirm our promising results.

The Surgical Optimal Mobility Score predicts mortality and length of stay in an Italian population of medical, surgical, and neurologic intensive care unit patients.

PURPOSE: We validated the Italian version of Surgical Optimal Mobility Score (SOMS) and evaluated its ability to predict intensive care unit (ICU) and hospital length of stay (LOS), and hospital mortality in a mixed population of ICU patients. MATERIALS AND METHODS: We applied the Italian version of SOMS in a consecutive series of prospectively enrolled, adult ICU patients. Surgical Optimal Mobility Score level was assessed twice a day by ICU nurses and twice a week by an expert mobility team. Zero-truncated Poisson regression was used to identify predictors for ICU and hospital LOS, and logistic regression for hospital mortality. All models were adjusted for potential confounders. RESULTS: Of 98 patients recruited, 19 (19.4%) died in hospital, of whom 17 without and 2 with improved mobility level achieved during the ICU stay. SOMS improvement was independently associated with lower hospital mortality (odds ratio, 0.07; 95% confidence interval [CI], 0.01-0.42) but increased hospital LOS (odds ratio, 1.21; 95% CI: 1.10-1.33). A higher first-morning SOMS on ICU admission, indicating better mobility, was associated with lower ICU and hospital LOS (rate ratios, 0.89 [95% CI, 0.80-0.99] and 0.84 [95% CI, 0.79-0.89], respectively). CONCLUSIONS: The first-morning SOMS on ICU admission predicted ICU and hospital LOS in a mixed population of ICU patients. SOMS improvement was associated with reduced hospital mortality but increased hospital LOS, suggesting the need of optimizing hospital trajectories after ICU discharge.

CD8+ NK cells are predominant in chimpanzees, characterized by high NCR expression and cytokine production, and preserved in chronic HIV-1 infection.

HIV-1 infection in humans results in an early and progressive NK cell dysfunction and an accumulation of an "anergic" CD56- CD16+ NK subset, which is characterised by low natural cytotoxicity receptor expression and low cytokine producing capacity. In contrast to humans, chimpanzee NK cells do not display a distinguishable CD56(bright) and CD56(dim) subset but, as shown here, could be subdivided into functionally different CD8+ and CD8- subsets. The CD8+ NK cells expressed significantly higher levels of triggering receptors including NKp46 and, upon in vitro activation, produced more IFN-gamma, TNF-alpha and CD107 than their CD8- counterparts. In addition, chimpanzee CD8- NK cells had relatively high levels of HLA-DR expression, suggestive of an activated state. Killing inhibitory receptors were expressed only at low levels; however, upon in vitro stimulation, they were up-regulated in CD8+ but not in CD8- NK cells and were functionally capable of inhibiting NKp30-triggered killing. In contrast to HIV-1-infected humans, infected chimpanzees maintained their dominant CD8+ NK cell population, with high expression of natural cytotoxicity receptors.

NKp44 expression, phylogenesis and function in non-human primate NK cells.

Molecular and functional characterization of the natural cytotoxicity receptor (NCR) NKp44 in species other than Homo sapiens has been elusive, so far. Here, we provide complete phenotypic, molecular and functional characterization for NKp44 triggering receptor on Pan troglodytes NK cells, the closest human relative, and the analysis of NKp44-genomic locus and transcription in Macaca fascicularis. Similar to H. sapiens, NKp44 expression is detectable on chimpanzee NK cells only upon activation. However, basal NKp44 transcription is 5-fold higher in chimpanzees with lower differential increases upon cell activation compared with humans. Upon activation, an overall 12-fold lower NKp44 gene expression is observed in P. troglodytes compared with H. sapiens NK cells with only a slight reduction in NKp44 surface expression. Functional analysis of 'in vitro' activated purified NK cells confirms the NKp44 triggering potential compared with other major NCRs. These findings suggest the presence of a post-transcriptional regulation that evolved differently in H. sapiens. Analysis of cynomolgus NKp44-genomic sequence and transcription pattern showed very low levels of transcription with occurrence of out-of-frame transcripts and no surface expression. The present comparative analysis suggests that NKp44-genomic organization appears during macaque speciation, with considerable evolution of its transcriptional and post-transcriptional tuning. Thus, NKp44 may represent an NCR being only recently emerged during speciation, acquiring functional relevance only in non-human primates closest to H. sapiens.

Increased natural cytotoxicity receptor expression and relevant IL-10 production in NK cells from chronically infected viremic HCV patients.

Hepatitis C virus (HCV) readily establishes high-level lifelong persistent infection in the majority of immunocompetent adults with failure of HCV-specific CD8+ CTL to clear viral replication. Virus-induced conditioning of innate immune responses is a possible mechanism that may contribute to the impairment of virus-specific CD8+ CTL responses. Here, we analyzed whether triggering of NK cell receptor expression and function is affected during chronic viremic HCV infection. Flow cytometric analysis of purified resting peripheral NK cells showed no evidence of NK cell activation, while analysis of natural cytotoxicity receptors (NCR) showed that NK cells from HCV-infected patients had selective increased expression of NKp30 and NKp46. NK cells had corresponding conserved cytotoxic activity against all targets with the exception of HepG2 hepatoma cells. Freshly separated NK cells from HCV patients showed significant production of IL-10 and normal concentrations of IFN-gamma upon cell-mediated triggering. Thus, increased expression of NKp30 during HCV infection with increased IL-10 production could contribute, once NK cells localize in the liver, to a NK-DC crosstalk leading to skewing of subsequent adaptive immune responses and lack of virus control.

Differential NKp30 inducibility in chimpanzee NK cells and conserved NK cell phenotype and function in long-term HIV-1-infected animals.

HIV-1 infection in chimpanzees, the closest human relative, rarely leads to disease progression. NK cells contribute to the shaping of adaptive immune responses in humans and show perturbed phenotype and function during HIV-1 infection. In this study, we provide full phenotypic, molecular, and functional characterization for triggering molecules (NKp46, NKp30 NKp80, and NKG2D) on Pan troglodytes NK cells. We demonstrate that, in this AIDS-resistant species, relevant differences to human NK cells involve NKp80 and particularly NKp30, which is primarily involved in NK-dendritic cell interactions. Resting peripheral chimpanzee NK cells have low or absent NKp30 molecule expression due to posttranscriptional regulation and increase its levels upon in vitro activation. Following long-standing HIV-1 infection, peripheral NK cells in chimpanzees have conserved triggering receptor expression and display moderate phenotypic and functional decreases only once activated and cultured in vitro. These data suggest that one of the keys to successful lentivirus control may reside in part in a different regulation of NK cell-triggering receptor expression.

Identification of immunodominant epitopes in inactivated Tat-vaccinated healthy and HIV-1-infected volunteers.

We analyzed the epitopes and the molecular forms of Tat recognized by the antibodies raised by Tat-toxoid vaccination in both healthy and HIV-infected volunteers. Tat-toxoid-vaccinated healthy volunteer sera reacted predominantly with peptides covering amino acids 1 through 24 and 46 through 60, corresponding to the N-terminus and basic domains of Tat. In contrast, whereas all sera from vaccinated HIV-1-positive patients reacted with the N-terminus and (with a single exception) with the basic domain, most of these sera also recognized peptides encompassing distinct domains of Tat, particularly the C-terminus (79-86). The sera of vaccinated individuals recognized both monomeric and oligomeric forms of Tat 1 through 86 or of Tat 1 through 101 and also blocked the ability of cell-released extracellular Tat to transactivate the HIV-1 LTR promoter. Synthetic Tat preincubated with sera from vaccinated individuals lost its functional activity as well. This is probably because of its inability to enter the cells as a result of immune complex formation with anti-Tat IgG. These data demonstrate that Tat-toxoid vaccination induces an efficient antibody response blocking the functional activity of Tat.

The HLA class II transcriptional activator blocks the function of HIV-1 Tat and inhibits viral replication.

The expression of HLA class II genes is under the control of a transcriptional activator, CIITA, encoded by the AIR-1 locus. Here we show that CIITA inhibits HIV-1 LTR transactivation mediated by Tat. The inhibition occurred when CIITA and Tat were transiently expressed in cells after transfection and, most importantly, when tat cDNA was transfected in cells expressing CIITA in a constitutive fashion and at physiological levels. Furthermore, CIITA inhibited the HIV-1 LTR transactivation mediated by extracellular Tat protein. CIITA inhibition of Tat function could be reversed by overexpression of Cyclin T1, the cellular cofactor used by Tat to facilitate elongation of viral transcripts. CIITA inhibition of Tat function had a dramatic effect on HIV-1 productive infection of human T cells because CIITA(+) T cells supported very poorly, if any, viral replication. These results indicate that sustained expression of CIITA in HIV-1-susceptible targets may down-regulate viral expression both in cells actively replicating the virus and in silently infected cells requiring exogenous Tat to reactivate virus from latency.