Basic fibroblast growth factor: serum levels in the female

Postischemic revascularization: from cellular and molecular mechanisms to clinical applications

After the onset of ischemia, cardiac or skeletal muscle undergoes a continuum of molecular, cellular, and extracellular responses that determine the function and the remodeling of the ischemic tissue. Hypoxia-related pathways, immunoinflammatory balance, circulating or local vascular progenitor cells, as well as changes in hemodynamical forces within vascular wall trigger all the processes regulating vascular homeostasis, including vasculogenesis, angiogenesis, arteriogenesis, and collateral growth, which act in concert to establish a functional vascular network in ischemic zones. In patients with ischemic diseases, most of the cellular (mainly those involving bone marrow-derived cells and local stem/progenitor cells) and molecular mechanisms involved in the activation of vessel growth and vascular remodeling are markedly impaired by the deleterious microenvironment characterized by fibrosis, inflammation, hypoperfusion, and inhibition of endogenous angiogenic and regenerative programs. Furthermore, cardiovascular risk factors, including diabetes, hypercholesterolemia, hypertension, diabetes, and aging, constitute a deleterious macroenvironment that participates to the abrogation of postischemic revascularization and tissue regeneration observed in these patient populations. Thus stimulation of vessel growth and/or remodeling has emerged as a new therapeutic option in patients with ischemic diseases. Many strategies of therapeutic revascularization, based on the administration of growth factors or stem/progenitor cells from diverse sources, have been proposed and are currently tested in patients with peripheral arterial disease or cardiac diseases. This review provides an overview from our current knowledge regarding molecular and cellular mechanisms involved in postischemic revascularization, as well as advances in the clinical application of such strategies of therapeutic revascularization.

Serum levels of fibroblast growth factor 2 in children with orthopedic diseases: potential role in predicting bone healing

Fibroblast growth factor 2 (FGF-2) plays an important role in the early phases of bone healing. In this study, we measured FGF-2 serum levels in 88 children undergoing surgical treatment for congenital (n = 49) or acquired (n = 39) orthopedic conditions, which were associated (n = 35) or not (n = 53) with bone lesions, to assess whether serum levels of FGF-2 varied according to the underlying disease and may predict clinical outcomes. FGF-2 serum levels were significantly lower in patients who did not heal after surgery (p = 0.008). Diagnostic accuracy was validated statistically, and the ROC curve provided a threshold value useful in discriminating good versus poor outcomes. The relationship between FGF-2 and bone healing was supported by in vitro experiments. A mineralization assay was performed on bone marrow stromal cells from three patients with congenital pseudarthrosis, who had low serum levels of FGF-2 and a poor clinical outcome after surgical treatment. Autologous serum alone was not sufficient to induce in vitro mineralization, but it did occur when cells were cultured with different sources of exogenous growth factors (GFs), including recombinant FGF-2 and homologous serum collected from children with fractures, high FGF-2 levels, and a good clinical outcome. In conclusion, our findings suggest that osteoinductive GFs are essential for bone repair, and that the amount of circulating FGF-2 may predict bone healing.

Fibroblast growth factor 2 induced proliferation in osteoblasts and bone marrow stromal cells: a whole cell model

Fibroblast growth factor 2 (FGF2) can enhance the proliferative capacity of bone and bone marrow stromal cells; however, the mechanisms behind this effect are not well described. We present a whole-cell kinetic model relating receptor-mediated binding, internalization, and processing of FGF2 to osteoblastic proliferative response. Focusing on one of the potential signaling complex stoichiometries, we utilized experimentally measured and modeled estimated rate constants to predict in vitro proliferation and distinguish between potential binding orders. We found that piecewise assemblage of a ternary signaling complex may occur in several ways depending on the local binding environment. Using experimental data of endocytosed FGF2 as a constraint, we have also shown evidence of potential multistep processes involved in heparan-sulfate proteoglycans-bound FGF2 release, internalization, and fragment formation in conjunction with the normal metabolism of the proteoglycan.

Modulation of distraction osteogenesis in the aged rat by fibroblast growth factor

This study explores a series of hypotheses related to modulation of bone formation using the distraction model. The tibial lengthening model was scaled down from dog to rat to use immunohistochemistry, in situ hybridization, and reverse transcription-polymerase chain reaction to evaluate cellular events during in vivo bone formation. Different delivery systems such as oral, intragastric, intravenous, subcutaneous, and local diffusion by either extraperiosteal or intramedullary routes, were developed and standardized. Systemic modulators, including diet (total enteral nutrition, calcium, phosphate, soy, whey, casein, lead, and alcohol) and hormones (estrogen, testosterone, growth hormone, and gonadectomy), were tested. To investigate the effects of aging on bone formation, rats of different age groups had tibial lengthening. The aging effect could be distinguished by a reproducible deficiency of endosteal bone formation, consistent with similar deficits in older adult patients having distraction osteogenesis or in patients with senile osteoporosis. Expression of endogenous fibroblast growth factor-2 at the cellular level during the coupled osteogenesis and angiogenesis in young rats was dramatically diminished in old rats. Exogenous fibroblast growth factor-2 reversed the endosteal deficits found in old rats having distraction osteogenesis.