Preoperative Glutamine Supplementation in Gastric Cancer-Thrombocyte Phagocytic Activity and Early Postoperative Outcomes.

BACKGROUND: The aim of this study was to determine the phagocytic activity of thrombocytes in patients with gastric cancer and to assess the effect of oral and parenteral preoperative glutamine-based immunonutrition on nutritional status, thrombocyte phagocytic activity, and early postoperative outcomes. METHODS: Patients suffering from invasive gastric cancer had been treated with preoperative immunonutrition with glutamine, and they were compared to patients without nutritional treatment. Nutritional status, percentage of weight loss, and BMI were assessed. Levels of total protein, albumin, cholesterol, triglycerides, platelets, and their phagocytic ability were measured twice. Postsurgical complications were assessed via the Clavien-Dindo classification. RESULTS: Group I consisted of 20 patients with an oral glutamine-10 g daily. Group II had 38 patients who received intravenous glutamine, 1.5 mL per kg body weight of Dipeptiven. Group III consisted of 25 patients who did not receive preoperative immunonutrition. In total, 47% of patients in Group I, 54% of patients in Group II, and 33% of patients in Group III were malnourished. In Group I, the percentage of phagocytizing platelet (%PhP) was 1.1 preoperatively and 1.2 postoperatively. The phagocytic index (PhI) was 1.0 and 1.1. In Group II, %PhP was 1.1 and 1.2 and PhI was 1.0 and 1.1. In Group III, the %PhP was 1.0 and 1.2 and PhI was 1.0 and 1.1. An increase in triglyceride level was observed in both immunonutrition groups. There was a decline in total protein and albumin level in Group II. In Group III, there was a decline in total protein, albumin, and cholesterol level. The total platelet count and PhI were increased in both immunonutrition groups. There was also a rise in %PhP in Group II. In Group III, there was a rise in blood platelet level, %PhP, and PhI. The complication rates were 53% in Group I, 29% in Group II, and 40% in Group III. CONCLUSIONS: In invasive gastric cancer, laboratory nutritional parameters are significantly reduced, causing malnutrition in 44.7% of patients. Oral glutamine supplementation inhibited the postoperative decline in protein metabolism parameters; however, this did not affect the reduction in the percentage of postoperative complications. Glutamine used preoperatively significantly reduced the percentage of serious surgical complications, regardless of the way it was supplemented. Patients with invasive gastric cancer have a significant decrease in platelet phagocytic activity. The administered preoperative parenteral nutrition and the surgical procedure itself influenced the improvement of the phagocytic activity of blood platelets. Glutamine did not have this effect, regardless of the route of administration.

Peripheral platelet phagocytosis in an extremely low birth weight infant:a case report.

A 768 g female neonate, born at 25 weeks' gestation, developed sepsis due to methicillin-resistant Staphylococcus epidermidis on day 14. Severe thrombocytopenia was observed, and hemophagocytic macrophages were identified in her peripheral blood smear. Cytokine profiles at the time of onset suggested that an inflammatory cytokine storm had activated lymphocytes and macrophages, leading to platelet phagocytosis. After administration of vancomycin for 14 days and immunoglobulin therapy, she improved without any complications. Considering the results of cytokine profiles, early intervention for infection may have prevented progression to hemophagocytic lymphohistiocytosis and reduced the severity of clinical symptoms.

ADAP restraint of STAT1 signaling regulates macrophage phagocytosis in immune thrombocytopenia.

Heightened platelet phagocytosis by macrophages accompanied by an increase in IFN-γ play key roles in the etiology of immune thrombocytopenia (ITP); however, it remains elusive how macrophage-mediated platelet clearance is regulated in ITP. Here, we report that adhesion and degranulation-protein adaptor protein (ADAP) restrains platelet phagocytosis by macrophages in ITP via modulation of signal transducer and activator of transcription 1 (STAT1)-FcγR signaling. We show that ITP was associated with the underexpression of ADAP in splenic macrophages. Furthermore, macrophages from Adap-/- mice exhibited elevated platelet phagocytosis and upregulated proinflammatory signaling, and thrombocytopenia in Adap-/- mice was mitigated by the depletion of macrophages. Mechanistically, ADAP interacted and competed with STAT1 binding to importin α5. ADAP deficiency potentiated STAT1 nuclear entry, leading to a selective enhancement of FcγRI/IV transcription in macrophages. Moreover, pharmacological inhibition of STAT1 or disruption of the STAT1-importin α5 interaction relieved thrombocytopenia in Adap-/- mice. Thus, our findings not only reveal a critical role for ADAP as an intracellular immune checkpoint for shaping macrophage phagocytosis in ITP but also identify the ADAP-STAT1-importin α5 module as a promising therapeutic target in the treatment of ITP.

Isolated case of platelet satellitism around white blood cells and phagocytosis by neutrophils and monocytes.

INTRODUCTION: Rarely, platelets can interact with other blood elements, forming platelet aggregates. This paper presents an isolated case of platelet satellitism around neutrophils, lymphocytes and monocytes with platelet phagocytosis by both neutrophils and monocytes. CASE PRESENTATION: The subject was an 89-year-old woman with breast cancer on anti-estrogenic hormone cancer therapy. Whole blood sample collected in a tube with EDTA (Ethylenediaminetetra-acetic acid) anticoagulant was analysed within 4 hours, using an XN haematology analyser (Sysmex). The CBC (complete blood count) presented the following results: WBC (White blood cell) 4.0 x 109/L, RBC (Red blood cell) 3.58 x 1012/L, haemoglobin 116 g/L, haematocrit 34.9%, MCV (Mean corpuscular volume) 97.5 fL, MCH (Mean corpuscular haemoglobin) 32.5 pg, MCHC (Mean corpuscular haemoglobin concentration) 33.2 g /dL, RDW (Red blood cell distribution width) 14.6% and PLT (Platelet) 136. CONCLUSION: This manuscript describes the platelet satellitism around neutrophils, lymphocytes and monocytes and the interesting, very rare and singular phenomenon of platelet phagocytosis by not only neutrophils but also monocytes.

SIRT1-induced deacetylation of Akt expedites platelet phagocytosis and delays HEMEC aging.

Maintaining the health of the endothelium is of critical importance to prevention against cell aging. The current study was performed to clarify the role of sirtuin1 (SIRT1) in platelet phagocytosis in cell aging and identified its downstream molecular mechanism. Platelet phagocytosis by human endometrial microvascular endothelial cells (HEMECs) was characterized by transmission electron and fluorescence microscopy. Functional experiments were conducted to examine platelet phagocytosis and cell aging using the overexpression or knockdown plasmids of SIRT1 and G alpha-interacting, vesicle-associated protein (GIRDIN) as well as Akt inhibitor and activator. It was found that SIRT1 facilitated platelet phagocytosis by HEMECs, contributing to inhibition of cell aging. Akt activation facilitated platelet phagocytosis and repressed cell aging. GIRDIN overexpression accelerated platelet phagocytosis by HEMECs, leading to a delay in cell aging. GIRDIN phosphorylation at Ser1417 was induced by Akt activation, while activation of Akt was induced by SIRT1-mediated deacetylation, consequently augmenting platelet phagocytosis and delaying cell aging. Taken together, SIRT1 delayed aging of HEMECs by deacetylating Akt, phosphorylating GIRDIN, and inducing platelet phagocytosis. The study highlights a possible target for the prevention of HEMEC aging.

Pseudothrombocytopenia: a case of platelet satellitism and phagocytosis by neutrophils.

Thrombocytopenia is a clinically important condition that can lead to several problems when not correctly diagnosed. A decrease of platelet counts due to an in vitro phenomenon, Pseudothrombocytopenia, can be misunderstood and unnecessarily treated. The present case study describes a 57-year-old male with a history of pancreas adenocarcinoma and a current Staphylococcus aureus infection without any signs or symptoms that could explain the low levels of platelets obtained after blood analysis. Blood smear evaluation detected both platelet satellitism and phagocytosis by neutrophils. As this sample was anticoagulated with ethylenediaminetetraacetic acid (EDTA), a new blood sample with citrate was analyzed. Platelet count was normal and no morphological abnormalities were detected. This case emphasizes the need for considering not only laboratory results but also the patient clinical information to guarantee the correct diagnosis and the best treatment possible.

In Vitro Monocyte/Macrophage Phagocytosis Assay for the Prediction of Drug-Induced Thrombocytopenia.

Phagocytosis of platelets by monocytes and macrophages is a primary mechanism of platelet clearance in vivo and has been increasingly implicated in playing an important role in thrombocytopenia mediated by monoclonal antibodies intended for therapeutic purposes. In the present article, we describe an in vitro flow cytometry assay to assess the effect of antibody-mediated platelet phagocytosis by monocytes. Freshly isolated platelets were labeled with a fluorescent probe, 5-chloromethylfluorescein diacetate (CMFDA) and then co-cultured with isolated peripheral blood mononuclear cells (PBMCs) from the same donor in the presence of increasing concentrations of a monoclonal antibody drug. After incubation, an increase in CMFDA fluorescence intensity of CD14 positive monocytes was evaluated by flow cytometry as an assessment for drug-mediated platelet phagocytosis by monocytes. The assay has been evaluated using both human and cynomolgus monkey cells for the prediction of drug-induced thrombocytopenia. © 2019 by John Wiley & Sons, Inc.

Long noncoding RNA MEG3 prevents vascular endothelial cell senescence by impairing miR-128-dependent Girdin downregulation.

Long noncoding RNAs (lncRNAs) are commonly associated with various biological functions, in which the function of lncRNA maternally expressed gene 3 (MEG3) has been identified in various cancers. Strikingly, an association between MEG3 with microRNAs (miRNAs), mRNAs, and proteins has been reported. This study investigates the role of MEG3 in vascular endothelial cell (VEC) senescence. Expression of Girdin and miR-128 was monitored in the blood vessel samples of young and old mice/healthy volunteers, along with the measurement of human umbilical vein endothelial cells (HUVECs). The relationship between MEG3/Girdin and miR-128 was determined and verified. Loss- and gain-of-function approaches were applied to analyze the regulatory effects of MEG3 on platelet phagocytosis and lipoprotein oxidation of HUVEC membrane. In addition, the effect of MEG3 on HUVEC senescence was evaluated by detection of the reactive oxygen species, telomerase activity, and telomere length. To further analyze the MEG3-mediated regulatory mechanism, miR-128 upregulation and inhibition were introduced into the HUVECs. Downregulated Girdin and upregulated miR-128 were found in the blood vessels of old individuals and old mice, as well as in senescent HUVECs. MEG3 downregulation was found to be capable of inhibiting Girdin but enhancing miR-128 expression. It was also indicated to inhibit platelet phagocytosis and reduce telomerase activity and telomere length, while enhancing lipoprotein oxidation and reactive oxygen species production, which ultimately contributed in preventing and protecting HUEVCs from senescence. These findings provide evidence supporting that MEG3 leads to miR-128 downregulation and Girdin upregulation, which promotes platelet phagocytosis, thus protecting VECs from senescence.

Anti-dengue virus nonstructural protein 1 antibodies contribute to platelet phagocytosis by macrophages.

Thrombocytopenia is an important clinical manifestation of dengue disease. The hypotheses concerning the pathogenesis of thrombocytopenia include decreased production and increased destruction or consumption of platelets. We previously suggested a mechanism of molecular mimicry in which antibodies (Abs) directed against dengue virus (DENV) nonstructural protein 1 (NS1) cross-react with platelets. Furthermore, several lines of evidence show activation of endothelial cells (ECs) and macrophages are related to dengue disease severity. Previous studies also suggested that Ab-opsonised platelets facilitate the engulfment of platelets by macrophages. Here we show that TNF-α-activated ECs upregulate adhesion molecule expression to enhance the binding of platelets and macrophages and lead to anti-DENV NS1 Ab-mediated platelet phagocytosis. We further demonstrate that the interaction between macrophages and TNF-α-activated ECs requires binding of FcγR with the Fc region of platelet-bound anti-DENV NS1 Abs. Importantly, the binding of anti-DENV NS1 Abs to platelets did not interfere with platelet adhesion to ECs. The adhesion molecules ICAM-1 and ß3 integrin expressed on ECs as well as the FcγR expressed on macrophages were critical in anti-DENV NS1 Ab-mediated platelet phagocytosis on activated ECs. Moreover, anti-DENV NS1 Abs dramatically enhanced platelet engulfment by macrophages in a murine model of DENV infection. Our study provides evidence for a novel role for anti-DENV NS1 Abs in the pathogenesis of thrombocytopenia in dengue disease by enhancing platelet phagocytosis by macrophages.

Satelitismo plaquetario: primeros dos casos reportados en Costa Rica / Plaquetary satellitism: first two cases reported in Costa Rica

Menos de 100 casos de Satelitismo Plaquetario se han descrito desde que en 1963, Field y MacLeod describieron por primera vez este fenómeno. Estos son los dos primeros casos del fenómeno descritos en la literatura Costarricense. El satelitismo plaquetario se observo en muestras sanguíneas con EDTA como anticoaguante y alrededor de los polimorfonucleares. A diferencia de otros casos descritos en la literatura la fagocitosis plaquetaria era evidente y no se observó pseudotrombocitopenia.

Field and MacLeod first reported the platelet satellitosis or satellitism in 1963 and to date is has been observed in no more than 100 cases. These are the first two cases reported in Costa Rica. This phenomenon occurred only in blood anticoagulated by EDTA and around polymorphonuclears. Pseudotrombocytopenia was not observed but platelet phagocytosis was evident.