Plasminogen activators in ischemic stroke: introduction

Involvement of urokinase-type plasminogen activator system in cancer: an overview

Currently, there are several studies supporting the role of urokinase-type plasminogen activator (uPA) system in cancer. The association of uPA to its receptor triggers the conversion of plasminogen into plasmin. This process is regulated by the uPA inhibitors (PAI-1 and PAI-2). Plasmin promotes degradation of basement membrane and extracellular matrix (ECM) components as well as activation of ECM latent matrix metalloproteases. Degradation and remodeling of the surrounding tissues is crucial in the early steps of tumor progression by facilitating expansion of the tumor mass, release of tumor growth factors, activation of cytokines as well as induction of tumor cell proliferation, migration, and invasion. Hence, many tumors showed a correlation between uPA system component levels and tumor aggressiveness and survival. Therefore, this review summarizes the structure of the uPA system, its contribution to cancer progression, and the clinical relevance of uPA family members in cancer diagnosis. In addition, the review evaluates the significance of uPA system in the development of cancer-targeted therapies.

Sickle cell pain: a critical reappraisal

Sickle cell pain includes 3 types: acute recurrent painful crises, chronic pain syndromes, and neuropathic pain. The acute painful crisis is the hallmark of the disease and the most common cause of hospitalization and treatment in the emergency department. It evolves through 4 phases: prodromal, initial, established, and resolving. Each acute painful episode is associated with inflammation that worsens with recurrent episodes, often culminating in serious complications and organ damage, such as acute chest syndrome, multiorgan failure, and sudden death. Three pathophysiologic events operate in unison during the prodromal phase of the crisis: vaso-occlusion, inflammation, and nociception. Aborting the acute painful episode at the prodromal phase could potentially prevent or minimize tissue damage. Our hypothesis is that managing these events with hydration, anti-inflammatory drugs, aggressive analgesia, and possibly vasodilators could abort the crisis and prevent or minimize further damage. Chronic pain syndromes are associated with or accompany avascular necrosis and leg ulcers. Neuropathic pain is not well studied in patients with sickle cell disease but has been modeled in the transgenic sickle mouse. Management of sickle cell pain should be based on its own pathophysiologic mechanisms rather than borrowing guidelines from other nonsickle pain syndromes.