Rumoured Media Hype Of FRAX597
0008), with the patients with uveitis exhibiting significantly higher levels of TPO than the control group (Figure 1). Figure 1 Thrombopoietin (TPO) levels in the Isoxsuprine aqueous humors of 16 patients with uveitis and 16 controls. Discussion The observation of higher levels of TPO in patients with noninfectious acute anterior uveitis raises questions relating to the cause and possible consequences of this condition. Although TPO plays an important multifunctional regulatory role in hematopoiesis and vasculogenesis that is closely related to VEGF29 there are many data that also relate it to inflammatory conditions. TPO is activated through the release of various proinflammatory cytokines, such as IL-1, IL-3, IL-6 and IL-11. These proinflammatory cytokines play a critical role in the triggering and development of multiple autoimmune conditions caused by dysregulation of the autoimmune response. All these cytokines interfere actively with cell immune and biochemical mediators at many levels. The regulation of this proinflammatory activity appears to be mediated by anti-inflammatory and immunosuppressive cytokines, such as IL-4, IL-10 or transforming growth factor (TGF)-��.30 There are several reports of a significant increase in the expression of the TPO gene under inflammatory conditions, which suggests that it acts as an acute-phase protein.31 It is also established that the synthesis of TPO in the liver can be induced by IL-6, while IL-6 stimulates thrombopoiesis through the action of TPO, and that the reactive thrombocytosis associated with some inflammatory conditions is mediated by IL-6 through the action of TPO.32�C34 A significant correlation between IL-6 and TPO is evident in the fact that the administration of IL-6 in patients with cancer produces an increase in TPO serum levels.35 Positive correlations have been found between TPO and C-reactive protein (CRP), but do not appear to affect platelet count. TPO acts as an acute-phase protein, and appears to be closely related to the action of IL-6 in inflammatory conditions.36,37 In some inflammatory diseases, such as Sch?nlein�CHenoch disease, an increase in TPO has also been described along with IL-6, which is thought to be an acute-phase reactant; in fact, a secondary increase in the production of TPO has been reported in this condition.38 TPO increases related to IL-6 have also been reported in the coronary disease inflammatory condition.39 The regulatory function of TPO has also been described in the differentiation of mast cells and its increase in patients with allergic asthma, which points to its involvement in immunoallergic conditions.21,22,40,41 The importance of platelets as major agents in the defense against infection and the induction of tissue inflammation and repair has been confirmed.42 Increases of IL-6 and TPO in the plasma of patients with inflammatory bowel disease and in sufferers of rheumatoid arthritis have also been documented.