Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

Modelling and simulation of flow and agglomeration in deep veins valves using discrete multi physics

The hemodynamics in flexible deep veins valves is modelled by means of discrete multi-physics and an agglomeration algorithm is implemented to account for blood accrual in the flow. Computer simulations of a number of valves typologies are carried out. The results show that the rigidity and the length of the valve leaflets play a crucial role on both mechanical stress and stagnation in the flow. Rigid and short membranes may be inefficient in preventing blood reflux, but reduce the volume of stagnant blood potentially lowering the chances of thrombosis. Additionally, we also show that in venous valves, cell agglomeration is driven by stagnation rather than mechanical stress.

Influenza vaccination is safe and effective in patients suffering from fibromyalgia syndrome

The fibromyalgia syndrome (FMS) is considered to result from the exposure of a genetically susceptible individual to various triggers, such as physical trauma, stress, viral infections etc. A possible role of vaccination in FMS etiology has been suspected. Our objective was to evaluate the efficacy and safety of influenza vaccination in FMS patients. Nineteen FMS patients underwent physical and dolorimetric examinations and answered the fibromyalgia impact questionnaire (FIQ), the widespread pain index (WPI) checklist and the symptoms severity scale (SSS), which are part of the 2010 diagnostic criteria. Thirty-eight healthy subjects were recruited as controls. All participants were vaccinated with the inactivated split virion influenza vaccine. Serum was collected for antibody titration. Six weeks after vaccination, sera were tested by hemagglutination (HI) against A/California (H1N1), A/Perth (H3N2) and B/Brisbane. Humoral response was defined as either a fourfold or greater increase in titer, or an increase from a non-protective baseline level of &lt;1/40 to a level of 1/40. No severe vaccination reactions were observed. No significant change was observed between WPI, SSS and FIQ values before and after vaccination, indicating no worsening of FMS symptoms. Vaccine immunogenicity: Six weeks after vaccination, FMS patients showed a significant increase in geometric mean titers of HI antibody. The rates of sero-protection increased from 22.9% for H1N1 to 89.5% post-vaccination. A significant increase in HI antibody titers was also demonstrated among healthy controls. Influenza vaccination was both safe and effective in FMS patients. In view of these results, FMS patients should be encouraged to undergo influenza vaccination according to the standard WHO recommendations.

Tissue factor expressed by circulating cancer cell-derived microparticles drastically increases the incidence of deep vein thrombosis in mice

BACKGROUND

The risk of thrombotic complications such as deep vein thrombosis (DVT) during tumor development is well known. Tumors release into the circulation procoagulant microparticles (MPs) that can participate in thrombus formation following vessel injury. The importance of this MP tissue factor (TF) in the initiation of cancer-associated DVT remains uncertain.

OBJECTIVE

To investigate how pancreatic cancer MPs promote DVT in vivo.

METHODS

We combined a DVT mouse model in which thrombosis is induced by flow restriction in the inferior vena cava with one of subcutaneous pancreatic cancer in C57BL/6J mice. We infused high-TF and low-TF tumor MPs to determine the importance of TF in experimental cancer-associated DVT.

RESULTS

Both tumor-bearing mice and mice infused with tumor MPs subjected to 3 h of partial flow restriction developed an occlusive thrombus; fewer than one-third of the control mice did. We observed that MPs adhered to neutrophil extracellular traps (NETs), which are functionally important players during DVT, whereas neither P-selectin nor glycoprotein Ib were required for MP recruitment in DVT. The thrombotic phenotype induced by MP infusion was suppressed by hirudin, suggesting the importance of thrombin generation. TF carried by tumor MPs was essential to promote DVT, as mice infused with low-TF tumor MPs had less thrombosis than mice infused with high-TF tumor MPs.

CONCLUSIONS

TF expressed on tumor MPs contributes to the increased incidence of cancer-associated venous thrombosis in mice in vivo. These MPs may adhere to NETs formed at the site of thrombosis.

Neutrophil extracellular traps promote deep vein thrombosis in mice

BACKGROUND

Upon activation, neutrophils can release nuclear material known as neutrophil extracellular traps (NETs), which were initially described as a part of antimicrobial defense. Extracellular chromatin was recently reported to be prothrombotic in vitro and to accumulate in plasma and thrombi of baboons with experimental deep vein thrombosis (DVT).

OBJECTIVE

To explore the source and role of extracellular chromatin in DVT.

METHODS

We used an established murine model of DVT induced by flow restriction (stenosis) in the inferior vena cava (IVC).

RESULTS

We demonstrate that the levels of extracellular DNA increase in plasma after 6 h IVC stenosis, compared with sham-operated mice. Immunohistochemical staining revealed the presence of Gr-1-positive neutrophils in both red (RBC-rich) and white (platelet-rich) parts of thrombi. Citrullinated histone H3 (CitH3), an element of NETs' structure, was present only in the red part of thrombi and was frequently associated with the Gr-1 antigen. Immunofluorescent staining of thrombi showed proximity of extracellular CitH3 and von Willebrand factor (VWF), a platelet adhesion molecule crucial for thrombus development in this model. Infusion of Deoxyribonuclease 1 (DNase 1) protected mice from DVT after 6 h and also 48 h IVC stenosis. Infusion of an unfractionated mixture of calf thymus histones increased plasma VWF and promoted DVT early after stenosis application.

CONCLUSIONS

Extracellular chromatin, likely originating from neutrophils, is a structural part of a venous thrombus and both the DNA scaffold and histones appear to contribute to the pathogenesis of DVT in mice. NETs may provide new targets for DVT drug development.

Serotonin stimulates platelet receptor shedding by tumor necrosis factor-alpha-converting enzyme (ADAM17)

BACKGROUND

Peripheral serotonin (5-hydroxytryptamine, 5-HT) is transported by platelets and released upon stimulation. In the platelet cytoplasm, 5-HT is transamidated to small GTPases, promoting alpha-granule release and primary hemostasis.

OBJECTIVE

We hypothesized that 5-HT could also stimulate platelet receptor shedding after binding to the membrane 5-HT receptor (5-HT2AR).

METHODS

Western blot and flow cytometry were used to determine levels of the adhesion receptor glycoprotein (GP)Ibalpha on platelets or its shed fragment glycocalicin in plasma and serum from wild-type mice, Tph1(-/-) mice lacking peripheral 5-HT, and mice lacking functional tumor necrosis factor-alpha-converting enzyme (TACE, ADAM17). Flow chamber experiments and intravital microscopy were used to examine the adhesive properties of platelets after stimulation of 5-HT2AR.

RESULTS

Glycocalicin was significantly reduced in Tph1(-/-) plasma and serum. In isolated platelets, 5-HT induced shedding of GPIbalpha, which was increased to 60% when 5-HT uptake was inhibited by the selective serotonin reuptake inhibitor fluoxetine. Specific 5-HT2AR agonism and antagonism suggested activation of this receptor. The shedding could not be induced in TACE(DeltaZn/DeltaZn) platelets, suggesting that activated TACE mediated the shedding of GPIbalpha. Intracellular signaling involved phosphorylation of p38 mitogen-activated protein kinase rather than G-protein signaling. 5-HT2AR stimulation decreased platelet adhesion to collagen-bound von Willebrand factor under arterial shear (1500 s(-1)) and incorporation into FeCl3-induced thrombi in mesenteric arterioles.

CONCLUSIONS

Stimulation of 5-HT2AR on platelets induces TACE-mediated shedding of GPIbalpha, the key adhesion molecule under high shear conditions. Our observations demonstrate a new pathway through which 5-HT could modulate cardiovascular disease.

Efficient in vitro expression of the human reverse transcriptase (hTERT) but impaired maturation in dendritic cells of lung cancer patients

13518

An innovative treatment strategy for patients with lung cancer is the targeting of tumor associated antigens with cellular effector cells. The telomerase catalytic subunit (hTERT) is an attractive target for cytotoxic T cells that is highly expressed in both NSCLC and SCLC cells. The aim of the study was the expression of hTERT in dendritic cells (DC) that are the most powerful antigen presenting cells for the induction of cellular immune responses. We used electrotransfection of DC with hTERT mRNA that enables an HLA independent whole antigen approach potentially targeting a wide range of hTERT epitopes. Immature DC were prepared from peripheral blood monocytes in serum-free growth medium, GM-CSF and IL-4. Subsequently the DC were electroporated with mRNA and matured in a cytokine cocktail consisting of IL-1 beta, IL-6, TNF-alpha and PGE2. Verification of hTERT mRNA transfection efficiency was performed by analyzing the induction of telomerase activity with the TRAP assay, the efficiency of GFP electrotransfection was determined by FACS. To optimize mRNA electrotransfection conditions the DCs of 3 healthy individuals were transfected with green fluorescent protein (GFP) mRNA. The percentage of electrotransfected DC was in between 18–89% (mean 46%). Subsequently we electrotransfected DCs in 3 lung cancer patients (1 SCLC, 2 NSCLC). In 1 patient GFP mRNA transfection resulted in 62% GFP positive DC. In the 2 other patients the telomerase activity in the DC 24 hrs after hTERT electrotransfection was equivalent to HL60 cells that biologically express high levels of hTERT. Importantly the DC of one patient did not mature after electrotransfection and incubation in the maturation cocktail. The same was true in another patient, in whom an electrotransfection was not done. In both patients the DC were expressing high levels of HLA-DR and no lineage markers, but CD83 as an indicator of maturation was found in only 1% and 9% respectively. Also the costimulatory molecules CD80 and CD86 were expressed at low levels only. These data show that strong hTERT expression can be achieved in DCs of lung cancer patients using mRNA electrotransfection but demontrate the need for other more potent maturation stimuli.

No significant financial relationships to disclose.

Induction of mast cell interactions with blood vessel wall components by direct contact with intact T cells or T cell membranes in vitro

BACKGROUND

Mast cells exert profound pleiotropic effects on immune cell reactions at inflammatory sites, where they are most likely influenced not only by the extracellular matrix (ECM) and inflammatory mediators but also by the proximity of activated T lymphocytes. We recently reported that activated T cells induce mast cell degranulation with the release of TNF-alpha, and that this activation pathway is mediated by lymphocyte function-associated antigen-1 (LFA-1)/intercellular adhesion molecule-1 (ICAM-1) binding.

OBJECTIVE

To determine how this contact between the two cell types can modulate mast cell behaviour in an inflammatory milieu by examining the adhesion of mast cells to endothelial cells and ECM ligands in an integrin-dependent manner.

METHODS

Human mast cells (HMC-1) were co-cultured with resting or activated T cells followed by testing their adhesion to endothelial cell and ECM ligands, stromal derived factor-1alpha (SDF-1alpha)-induced migration, and western blotting.

RESULTS

Co-culturing HMC-1 with activated, but not with resting T cells resulted in marked stimulation of mast cell adhesion to vascular cell adhesion molecule-1 and ICAM-1 in a very late antigen-4- and LFA-1-dependent fashion. In addition, activated T cells or T cell membranes promoted HMC-1 adhesion to fibronectin (FN) and laminin. This effect was accompanied by the phosphorylation of extracellular regulated kinase and p38, but not of c-Jun N-terminal kinase. Importantly, the adhesive property of mast cells depended exclusively on the direct contact between the two cell types, since neither supernatants from activated T cells nor separation of the two cell populations with a porous membrane affected mast cell adhesion to FN. Furthermore, similar results were obtained when mast cells were incubated with purified membranes from activated T cells. These results suggest that, in addition to stimulating mast cell degranulation, the proximity of activated T lymphocytes to mast cells can mediate the adhesion of mast cell precursors to the endothelial ligands and ECM. Activated T cells also stimulated SDF-1alpha-induced mast cell migration.

CONCLUSION

This symbiotic relationship between the two types of immune cells may serve to direct mast cells to specific sites of inflammation where their effector functions are required.

Differential response of platelets to chemokines: RANTES non-competitively inhibits stimulatory effect of SDF-1 alpha

BACKGROUND

Among the chemokines related to CXC and CC receptor groups and released from platelets, leukocytes and endothelial cells, SDF-1, TARC and MDC have been found to be platelet agonists. Platelets do not contain SDF-1 alpha. In contrast, RANTES is constitutively present in platelet alpha-granules and released upon platelet activation.

OBJECTIVES

To study a possible role of RANTES as a modulator of SDF-1 alpha effect on platelets, in relation to CXCR4 and various CC receptors.

METHODS

CXCR-4 (CXCL12) receptor expression and platelet activation were evaluated by flow cytometry, platelet deposition was studied by cone and plate(let) analyzer, and platelet aggregation by turbidometric aggregometry.

RESULTS

Flow cytometry studies revealed similar expression of CXCR-4, the specific receptor of SDF-1 alpha on intact, inactivated, and activated platelets. Preincubation of platelets with RANTES affected neither CXCR-4 expression, nor SDF-1 alpha binding to the platelet membrane. In the presence of fibrinogen, SDF-1 alpha activated gel-filtered platelets. RANTES did not activate platelets, but substantially (by 70%) inhibited SDF-1 alpha-induced fibrinogen binding. Similarly, RANTES abrogated the promoting effect of SDF-1 alpha on whole blood platelet adhesion to endothelial cell monolayer under venous flow conditions. In platelet-rich plasma, RANTES moderately inhibited SDF-1 alpha-induced platelet aggregation, while it did not affect aggregation induced by thrombin-receptor activation peptide, adenosine diphosphate, or phorbol 12-myristate 13-acetate. A synergistic inhibitory effect of RANTES and prostaglandin E1 used at subthreshold concentrations, on SDF-1 alpha-induced aggregation and SDF-1 alpha-induced fibrinogen binding to platelets was observed, which may suggest involvement of RANTES in a cAMP-dependent signal transduction pathway.

CONCLUSIONS

RANTES non-competitively inhibits activation of platelets by SDF-1 alpha, and thus may play a regulatory role in platelet response to inflammation.

Clinical signs of West Nile virus encephalomyelitis in horses during the outbreak in Israel in 2000

Between August and October 2000, 76 horses were reported by veterinary practitioners as having signs of a neurological disorder, varying from an involvement of the spinal cord alone to the entire central nervous system; 15 of the horses died or were euthanased as a result of their grave prognosis or secondary complications. At the same time, an outbreak of West Nile virus infection affected people and birds, principally domestic geese. West Nile virus was isolated from four of the horses with encephalomyelitis and five other horses seroconverted, indicating that the virus was the probable cause of the outbreak in horses. Three of the cases from which the virus was isolated are described briefly and one case is described in detail. This horse behaved abnormally and had general proprioceptive deficits in all four limbs. Its neurological condition deteriorated after two days and severe inspiratory dyspnoea due to a failure to abduct the arytenoids necessitated a tracheostomy. It died on the fourth day and histological lesions were observed in the brain stem and grey matter of the spinal cord.

Augmentation of RANTES-induced extracellular signal-regulated kinase mediated signaling and T cell adhesion by elastase-treated fibronectin

T cells migrating across extracellular matrix (ECM) barriers toward their target, the inflammatory site, should respond to chemoattractant cytokines and to the degradation of ECM by specific enzymes. In this study, we examined the effects of RANTES and ECM proteins treated with human leukocyte elastase on T cell activation and adhesion to the ECM. We found that human peripheral blood T cells briefly suspended with RANTES (0.1-100 ng/ml) had increased phosphorylation of their intracellular extracellular signal-regulated kinase (ERK), a mitogen-activated protein kinase involved in the activation of several intracellular downstream effector molecules implicated in cell adhesion and migration. Consequently, a small portion (12-20%) of the responding cells adhered to fibronectin (FN). However, when the T cells were exposed to RANTES in the presence of native immobilized FN, laminin, or collagen type I, ERK phosphorylation was partially inhibited, suggesting that this form of the ECM proteins can down-regulate RANTES-induced intracellular signaling. In contrast, when the T cells were exposed to RANTES in the presence of elastase-treated immobilized FN, but not to elastase-treated laminin, ERK phosphorylation was markedly increased. Furthermore, a large percentage (30%) of RANTES-activated T cells adhered to the enzymatically treated FN in a beta1 integrin-dependent fashion. Thus, while migrating along chemotactic gradients within the ECM, T cells can adapt their adhesive performance according to the level of cleavage induced by enzymes to the matrix.

Combinatorial signals by inflammatory cytokines and chemokines mediate leukocyte interactions with extracellular matrix

On their extravasation from the vascular system into inflamed tissues, leukocytes must maneuver through a complex insoluble network of molecules termed the extracellular matrix (ECM). Leukocytes navigate toward their target sites by adhering to ECM glycoproteins and secreting degradative enzymes, while constantly orienting themselves in response to specific signals in their surroundings. Cytokines and chemokines are key biological mediators that provide such signals for cell navigation. Although the individual effects of various cytokines have been well characterized, it is becoming increasingly evident that the mixture of cytokines encountered in the ECM provides important combinatorial signals that influence cell behavior. Herein, we present an overview of previous and ongoing studies that have examined how leukocytes integrate signals from different combinations of cytokines that they encounter either simultaneously or sequentially within the ECM, to dynamically alter their navigational activities. For example, we describe our findings that tumor necrosis factor (TNF)-alpha acts as an adhesion-strengthening and stop signal for T cells migrating toward stromal cell-derived factor-1alpha, while transforming growth factor-beta down-regulates TNF-alpha-induced matrix metalloproteinase-9 secretion by monocytes. These findings indicate the importance of how one cytokine, such as TNF-alpha, can transmit diverse signals to different subsets of leukocytes, depending on its combination with other cytokines, its concentration, and its time and sequence of exposure. The combinatorial effects of multiple cytokines thus affect leukocytes in a step-by-step manner, whereby cells react to cytokine signals in their immediate vicinity by altering their adhesiveness, directional movement, and remodeling of the ECM.

Induction of interactions between CD44 and hyaluronic acid by a short exposure of human T cells to diverse pro-inflammatory mediators

Migration of T cells into extravascular sites of inflammation is mediated by cell-cell and cell-matrix adhesion receptors, including the hyaluronan-binding glycoprotein, CD44. The biochemical nature of CD44 variants and the ligand specificity, function and the regulation of activation of CD44 expressed on various cell types have been extensively studied. However, little is still known about the short-term influence of cytokines and chemokines on the activation of CD44 on human T cells. Therefore, we studied the role of inflammatory mediators in regulating the adhesion of T cells from human peripheral blood to immobilized hyaluronan under static or shear stress conditions. We found that the CD44-dependent adhesion, under static and shear stress (i.e. relative gradual resistance to flow of 150 and 1500 s-1) conditions, of T cells to hyaluronan requires a T-cell activation of 2-3 hr and is regulated by the cross-linking of CD3, cytokines (e.g. interleukin-2 and tumour necrosis factor-alpha), and chemokines (e.g. MIP-1beta, interleukin-8, and RANTES). This T-cell adhesion was manifested by polarization, spreading and co-localization of cell surface CD44 with a rearranged actin cytoskeleton in hyaluronan-bound T cells. Thus, cytokines and chemokines present in the vicinities of blood vessel walls or present intravascularly in tissues where immune reactions take place, can rapidly activate the CD44 molecules expressed on T cells.

The role of apoptosis in normal and abnormal embryonic development

Programmed cell death or apoptosis is a widespread biological phenomenon. Apoptosis is characterized by typical cell features such as membrane blebbing, chromatin condensation, and DNA fragmentation. It involves a number of membrane receptors (e.g., Fas, TNFR) and a cascade of signal transduction steps resulting in the activation of a number of cysteine proteases known as caspases. Disordered apoptosis may lead to carcinogenesis and participates in the pathogenesis of Alzheimer disease, Parkinson disease, or AIDS. Programmed cell death plays an important role in the processes of gamete maturation as well as in embryo development, contributing to the appropriate formation of various organs and structures. Apoptosis is one of the mechanisms of action of various cytotoxic agents and teratogens. Teratogen-induced excessive death of embryonic cells is undoubtedly one of the most important events preceding the occurrence of structural abnormalities, regardless of their nature. Therefore understanding the mechanisms involved in physiological as well as in disturbed or dysregulated apoptosis may lead to the development of new methods of preventive treatment of various developmental abnormalities. The present review summarizes data on the mechanisms of programmed cell death and concentrates on apoptosis involved in normal or disturbed gametogenesis and in normal and abnormal embryonic development.

Traumatic hypogastric artery bleeding controlled with bipolar desiccation during operative laparoscopy

During multipuncture operative laparoscopy to excise peritoneal endometriosis involving the pelvic sidewall near the origin of the uterine artery, the lower portion of the hypogastric artery was perforated. The acute hemorrhage was controlled by immediately grasping the lacerated blood vessel with a 5-mm atraumatic grasping forceps. A Kleppinger bipolar forceps set at 25 W desiccated and sealed the artery successfully. As no further bleeding was noted, the procedure was terminated. The patient remained overnight for observation, and was discharged from the hospital the next day. She is doing well 18 months after the injury and repair.

Automatic Contour Detection Using a "Fixed-Point Hachimura-Kuwahara Filter" for SPECT Attenuation Correction

Attenuation correction for single-photon emission computed tomography (SPECT) usually assumes a uniform attenuation distribution within the body surface contour. Previous methods to estimate this contour have used thresholding of a reconstructed section image. This method is often very sensitive to the selection of a threshold value, especially for nonuniform activity distributions within the body. We have proposed the "fixed-point Hachimura-Kuwahara filter" to extract contour primitives from SPECT images. The Hachimura-Kuwahara filter, which preserves edges but smoothes nonedge regions, is applied repeatedly to identify the invariant set-the fixed-point image-which is unchanged by this nonlinear, two-dimensional filtering operation. This image usually becomes a piecewise constant array. In order to detect the contour, the tracing algorithm based on the minimum distance connection criterion is applied to the extracted contour primitives. This procedure does not require choice of a threshold value in determining the contour. SPECT data from a water-filled elliptical phantom containing three sources was obtained and scattered projections were reconstructed. The automatic edge detection procedure was applied to the scattered window reconstruction, resulting in a reasonable outline of the phantom.