While heparin has been used almost exclusively as a blood anticoagulant, important literature demonstrates that it also has broad anti-inflammatory activity. Herein, using low anti-coagulant 2-O,3-O-desulfated heparin (ODSH), we demonstrate that most of the anti-inflammatory pharmacology of heparin is unrelated to anticoagulant activity. ODSH has low affinity for anti-thrombin III, low anti-Xa, and anti-IIa anticoagulant activities and does not activate Hageman factor (factor XII). Unlike heparin, ODSH does not interact with heparin-platelet factor-4 antibodies present in patients with heparin-induced thrombocytopenia and even suppresses platelet activation in the presence of activating concentrations of heparin. Like heparin, ODSH inhibits complement activation, binding to the leukocyte adhesion molecule P-selectin, and the leukocyte cationic granular proteins azurocidin, human leukocyte elastase, and cathepsin G. In addition, ODSH and heparin disrupt Mac-1 (CD11b/CD18)-mediated leukocyte adhesion to the receptor for advanced glycation end products (RAGE) and inhibit ligation of RAGE by its many proinflammatory ligands, including the advanced glycation end-product carboxymethyl lysine-bovine serum albumin, the nuclear protein high mobility group box protein-1 (HMGB-1), and S100 calgranulins. In mice, ODSH is more effective than heparin in reducing selectin-mediated lung metastasis from melanoma and inhibits RAGE-mediated airway inflammation from intratracheal HMGB-1. In humans, 50% inhibitory concentrations of ODSH for these anti-inflammatory activities can be achieved in the blood without anticoagulation. These results demonstrate that the anticoagulant activity of heparin is distinct from its anti-inflammatory actions and indicate that 2-O and 3-O sulfate groups can be removed to reduce anticoagulant activity of heparin without impairing its anti-inflammatory pharmacology.

Freshly excised human head and neck cancers (219 primary cancers; 64 metastatic lymph node cancers) were analyzed for the immune inhibitory mediators released from the cancer tissues and the immune infiltrate within the tumor. Significant levels of the immune inhibitory mediators transforming growth factor-beta (TGF-beta), prostaglandin E2 (PGE2) and interleukin-10 (IL-10) were released from these cancers. Also released was granulocyte-macrophage colony-stimulating factor (GM-CSF), whose secretion was associated with an intratumoral presence of CD34+ cells. We have previously shown that CD34+ cells within human head and neck cancers are immune inhibitory granulocyte-macrophage progenitor cells. The presence of TGF-beta, PGE2 and IL-10 was associated with a reduced content of CD8+ T-cells within the cancers. The CD4+ cell content appeared to be less affected by these immune inhibitory mediators. Instead, parameters indicative of CD4+ cell function (p55 IL-2 receptor expression, release of IL-2 and IFN-gamma) were diminished in cancers that released higher levels of TGF-beta, IL-10 and GM-CSF and had a higher CD34+ cell content. Furthermore, metastatic cancers released higher levels of the soluble immune inhibitory mediators and lower levels of IFN-gamma and IL-2 than did primary cancers, although CD34+ cells were similarly present in both primary and metastatic cancers. Our results show that human head and neck cancers have a multiplicity of non-mutually exclusive mechanisms of immune suppression that are most prominently associated with reduced CD8+ cell influx and reduced influx and altered function of intratumoral CD4+ cells.

Human head and neck squamous cell carcinomas (HNSCC) that produce high levels of granulocyte-macrophage colonystimulating factor (GM-CSF) have been shown to contain CD34 1 natural suppressor cells that inhibit the activity of intratumoral T-cells. The present study evaluated whether GM-CSF production and the presence of CD34 1 cells within primary HNSCC would translate into increased recurrence, metastasis or cancer-related death during the 2 years following surgical excision. Freshly excised primary HNSCC of 20 patients that subsequently developed disease, and of 17 patients that remained with no evidence of disease were analyzed for production of GM-CSF and for CD34 1 cell content. The cancers of patients that subsequently developed recurrences or metastatic disease produced almost 4-fold the levels of GM-CSF and had approximately 2.5-fold the number of CD34 1 cells as did cancers of patients that remained disease-free. In a second method of analysis, the prognostic significance of high vs. low GM-CSF and CD34 1 cell values was evaluated. These analyses showed that patients whose cancers produced high GM-CSF levels or had a high CD34 1 cell content had a disproportionately high incidence of recurrence or metastatic disease (94% and 100%, respectively), while the majority of patients whose primary cancers produced low levels of GM-CSF or had a low CD34 1 cell content remained disease-free (16% and 19%, respectively). Our results indicate that the presence of CD34 1 cells in GM-CSFproducing HNSCC is associated with a poorer prognosis for the cancer patients and suggest the utility of these parameters as prognostic indicators of outcome. Mechanistically, our results suggest that the presence of immune suppressive CD34 1 cells in GM-CSF-producing HNSCC leads to increased tumor recurrence or metastasis. Int. J. Cancer 74:69-74.r 1997 Wiley-Liss, Inc.Head and neck cancers, most of which are squamous cell carcinomas (HNSCC), are vulnerable to immune effector cells such as macrophages, natural killer cells and cytotoxic T-lymphocytes (Chikamatsu et al., 1995;Rabinowich et al., 1992). However, patients with HNSCC cancers are particularly prone to have defects in their immune defenses (Gooding et al., 1995;Hadden et al., 1994). Part of this immune suppression has been shown to be directly induced by soluble immune suppressive factors produced by the cancer (O'Mahony et al., 1993). However, cancers can also mediate immune suppression indirectly by stimulating immune suppressor cell activity. The immune suppressor cells that may be induced by human HNSCC have not been extensively studied or described, but have been well documented in many other cancer types of both humans and animals. Some human cancers induce suppressive T-cells that are inhibitory to immune functions, including anti-tumor T-cell reactivities (Chakraborty et al., 1991). Suppression of T-cell function in patients with HNSCC as well as with other cancers can also be due to monocytes or macrophages secreting the immune suppressive mediator prostaglandin E 2...

SummaryRivaroxaban is an oral, direct activated Factor Xa (FXa) inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. Currently available anticoagulants include unfractionated heparin (UFH) and low molecular weight heparins (LMWHs); however, their use can be restricted by heparin-induced thrombocytopenia (HIT). HIT is usually caused by the production of antibodies to a complex of heparin and platelet factor-4 (PF4). This study was performed to evaluate, in vitro, the potential of rivaroxaban as an anticoagulant for the management of patients with HIT. UFH, the LMWH enoxaparin, fondaparinux and the direct thrombin inhibitor argatroban were tested to enable comparative analyses. Rivaroxaban did not cause platelet activation or aggregation in the presence of HIT antibodies, unlike UFH and enoxaparin, suggesting that rivaroxaban does not cross-react with HIT antibodies. Furthermore, rivaroxaban did not cause the release of PF4 from platelets and did not interact with PF4, unlike UFH and enoxaparin. These findings suggest that rivaroxaban may be a suitable anticoagulant for the management of patients with HIT.

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