Detecting the developmental toxicity of bFGF in the embryonic stem cell test using differential gene expression of differentiation-related genes.

Basic fibroblast growth factor (bFGF) is a mitogenic cytokine that can stimulate mesoderm-and neuroectoderm-originated cell proliferation. This study was performed to investigate the effects of bFGF on cell differentiation and the expression of specific markers at different embryonic developmental stages. We firstly evaluated the embryotoxic potential of bFGF in vitro using a modified EST protocol. Sequentially, we further investigated how bFGF impact the different tissue-special genes and proteins expressions during the differentiation of murine ES cells in vitro and attempt to reveal the effects of bFGF on differentiation processes. This analysis was focused on key tissue- and stage-specific genes involved in ectodermal, mesodermal, and endodermal differentiation, including ectodermal-specific gene Nestin, Oligo2 and Syn, mesodermal-specific gene MHC and MyoD, and endodermal-specific gene GATA6, TTR and ALB, as well as undifferentiated gene Sox-2 and Oct-4. The results demonstrate that bFGF could promote expression of ectodermal-specific genes and protein, but suppress the expressions of endoderm-specific and some mesoderm-specific gene and protein. A conclusion can be drawn that bFGF exhibits weak embryotoxicity and mainly promotes ES cell differentiation towards the ectodermal lineages but suppress differentiation into endoderm lineages. These opposing effects of bFGF on the embryonic development of the three germ layers may be related to its weak embryotoxic potential. More specifically, inhibition of expression of the endodermal-specific markers transthyretin (TTR), and albumin (ALB) by bFGF may be of more value in detecting the embryotoxic potential of bFGF.

Complement factor 1 inhibitor improves cardiopulmonary function in neonatal cardiopulmonary bypass.

BACKGROUND: The inflammatory insult associated with cardiopulmonary bypass (CPB) continues to result in morbidity for neonates undergoing complex repair of congenital cardiac defects. Complement and contact activation are important mediating processes involved in this injury. Complement factor 1 esterase inhibitor (C1-inh), a natural inhibitor of complement, kallikrein, and coagulation pathways, may be decreased in children undergoing cardiac operations requiring CPB. We tested the hypothesis that C1-inh supplementation will ameliorate the cardiac and pulmonary dysfunction in a model of neonatal CPB. METHODS: Fifty-two neonatal pigs were randomly assigned to receive 0 IU (n = 22), 500 IU (n = 15), 1,000 IU (n = 8), or 1,500 IU (n = 7) of C1-inh. Doses were delivered 5 minutes before starting 90 minutes of normothermic CPB. Pulmonary and cardiovascular measures were taken before and 5, 30, and 60 minutes after CPB. RESULTS: Five animals did not survive CPB. The C1-inh concentration post-CPB increased monotonically with increasing dose (p < 0.001). Weight gain was significantly less in the 1,500 IU group (0.24 +/- 0.10 kg versus 0.38 +/- 0.09 kg, p = 0.001). Dynamic compliance increased with C1-inh dose from 0 to 500 IU by 23% +/- 4% (p < 0.001), but the increase leveled off at the higher doses. Alveolar-arterial O2 gradient decreased with C1-inh dose (p = 0.009). Time derivative of left ventricular pressure (dP/dt(max)) increased significantly with increasing dose (p = 0.016). At the highest dose of C1-inh, the time constant of isovolumic relaxation was increased (p = 0.018). CONCLUSIONS: The C1-inh supplementation results in improved pulmonary and systolic cardiac function in a model of neonatal CPB. The negative effect on diastolic function requires further investigation.

C1-esterase inhibitor and a novel peptide inhibitor improve contractile function in reperfused skeletal muscle.

To determine the role of inhibition of complement activation in the contractile function of skeletal muscle ischemia-reperfusion (I/R) injury, the rat extensor digitorum longus (EDL) muscles underwent 3 h ischemia and received human C1-esterase inhibitor (C1-INH, 100 IU/kg), a synthetic C1q A chain peptide with a similar inhibitory effect on activated C1 (peptide, 5 mg/kg), or human serum albumin control. Results showed a significant overall increase in tetanic contractile forces of the reperfused EDL in both C1-INH and peptide groups compared to controls. Maximum improvement occurred with peptide treatment at 120-Hz stimulation, with an increase in force from 38 +/- 4% of normal in controls to 52 +/- 4% in peptide-treated rats. There were no significant differences between C1-INH and peptide groups. Plasma C3 and C4 activities were significantly increased in both treated groups, suggesting inhibition of complement activation. Our results suggest that complement activation is involved in I/R injury, and inhibition of complement activation may therefore represent a potential therapeutic approach to reducing or preventing I/R injury.