Activated protein C differentially regulates both viability and differentiation of osteoblasts mediated by bisphosphonates

Activated protein C (APC) is a cytoprotective anticoagulant that can promote cutaneous healing. We examined the effect of APC on viability and differentiation of the osteoblastic line, MG63, in the presence and absence of bisphosphonates (BPs). Osteoblasts were cultured and treated for 24 or 48 h with Alendronate (Aln), Zoledronate (Zol) or Pamidronate (Pam) at concentrations ranging from 10-4 to 10-6 M. Cell differentiation was measured using type 1 collagen production, Alizarin red staining and alkaline phosphatase activity, whereas cell viability was assessed using MTT and crystal violet assays. All three BPs induced MG63 cell death in a dose- and time-dependent manner. Pam- and Zol-related cell death was prevented by APC treatment; however, cell death induced by Aln was accelerated by APC. APC induced MG63 cell differentiation that was enhanced by Aln, but inhibited by Pam or Zol. Endothelial protein C receptor (EPCR) was expressed by MG63 cells and mediated the protective effect of APC on Zol-induced viability. In summary, we have demonstrated that (1) APC favorably regulates MG63 viability and differentiation toward bone growth, (2) APC differentially regulates the effects of specific BPs and (3) at least part of the effects of APC is mediated through EPCR. These findings highlight the potential importance of the PC pathway in bone physiology and provide strong evidence that APC may influence bone cells and has potential to be a therapeutic drug for bone regeneration, depending on concurrent BP treatment.

Proteína C recombinante activada en pancreatitis aguda grave sin infección documentada: revisión en relación a un caso clínico / Recombinant human activated protein C in serious acute pancreatitis without documented infection: review in relation to a clinical case

Presentamos el caso de un paciente con pancreatitis aguda grave (PAG) que evolucionó rápidamente con un Síndrome de Respuesta Inflamatoria Sistémica (SIRS) severo manejado con Proteína C humana recombinante (PCHR). Entre 10 a 15 por ciento de las pancreatitis agudas desarrollarán un SIRS, que lleva a un curso fulminante con extensa necrosis y falla multiorgánica. En series internacionales esta condición se asocia a una mortalidad mayor al 25 por ciento, pero existen escasas publicaciones sobre el uso de PCHR en pacientes con PAG. Algunos estudios ya han descrito que en presencia de una respuesta inflamatoria severa documentada con score de APACHE mayor a 25 existe una recuperación sustancial con el uso del PCRH. Comunicamos su cuadro clínico, evolución y resultado.

Expression and characterization of a mutant recombinant blood coagulation factor VIII (rFVIII (m))

In an earlier study, a site directed mutant rFVIII (rFVIII(m), Arg(336) -> Gln(336)) expressed in baculovirus-insect cell (Sf9) system was found to sustain high level activity during incubation at 37 for 24 h while the cofactor activity of normal plasma was declined steadily. In this study, a mutant B-domain deleted rFVIII(m), Arg(336) -> Gln(336) expressed in baculovirus-insect cell (Sf9) system was characterized for its enzymatic and chemical properties. The expressed rFVIII(m) and plasma FVIII (pFVIII) were purified by immunoaffinity column chromatography and identified by Western blot analysis. The partially purified rFVIII(m) exhibited cofactor specific activity of 2.01 X 10(3)units/mg protein. The molecular weight of rFVIII(m) ranged between 40 to 150 kDa with a major band at 150 kDa. Treatment of both rFVIII(m) and pFVIII with thrombin increased their cofactor activity in a similar pattern. Treatment of both the activated rFVIII(m) and native FVIII with APC decreased their cofactor activities, however, the former exhibited a slower decrease than the latter, although no significant difference was present. rFVIII(m) formed a complex with vWF, resulting in a stabilized form, and the lag period of thrombin-mediated activating was extended by vWF association. These results implicated that rFVIII(m) expressed in baculovirus-insect cell system had a comparable capacity as FVIII cofactor activity and might be a good candidate for the FVIII replacement therapy for hemophilia A patients.