epidermal-growth-factor and tricalcium-phosphate

Transplantation of freshly-aspirated autologous bone marrow, together with a scaffold, is a promising clinical alternative to harvest and transplantation of autologous bone for treatment of large defects. However, survival proliferation, and osteogenic differentiation of the marrow-resident stem and progenitor cells with osteogenic potential can be limited in large defects by the inflammatory microenvironment. Previous studies using EGF tethered to synthetic polymer substrates have demonstrated that surface-tethered EGF can protect human bone marrow-derived osteogenic stem and progenitor cells from pro-death inflammatory cues and enhance their proliferation without detriment to subsequent osteogenic differentiation. The objective of this study was to identify a facile means of tethering EGF to clinically-relevant βTCP scaffolds and to demonstrate the bioactivity of EGF tethered to βTCP using stimulation of the proliferative response of human bone-marrow derived mesenchymal stem cells (hBMSC) as a phenotypic metric. We used a phage display library and panned against βTCP and composites of βTCP with a degradable polyester biomaterial, together with orthogonal blocking schemes, to identify a 12-amino acid consensus binding peptide sequence, LLADTTHHRPWT, with high affinity for βTCP. When a single copy of this βTCP-binding peptide sequence was fused to EGF via a flexible peptide tether domain and expressed recombinantly in E. coli together with a maltose-binding domain to aid purification, the resulting fusion protein exhibited modest affinity for βTCP. However, a fusion protein containing a linear concatamer containing 10 repeats of the binding motif the resulting fusion protein showed high affinity stable binding to βTCP, with only 25% of the protein released after 7 days at 37oC. The fusion protein was bioactive, as assessed by its abilities to activate kinase signaling pathways downstream of the EGF receptor when presented in soluble form, and to enhance the proliferation of hBMSC when presented in tethered form on commercial βTCP bone regeneration scaffolds.

Topics: Amino Acid Sequence; Calcium Phosphates; Connective Tissue Cells; Epidermal Growth Factor; Humans; Molecular Sequence Data; Multipotent Stem Cells; Peptides; Protein Binding; Protein Multimerization; Stromal Cells; Tissue Scaffolds

To determine the concentration of naturally available biologic mediators in autologous platelet concentrates and their correlation with periodontal regeneration outcomes.. In 25 patients with two intra-bony defects each, an autologous platelet concentrate (APC) was prepared by a laboratory thrombocyte apheresis technique pre-operatively. Both defects were treated using a bioresorbable guided tissue regeneration-membrane in combination with tricalciumphosphate (TCP). In the test defect, APC was additionally applied. In the APC, platelets were counted and the levels of growth factors and cytokines were determined by ELISA. Correlations between the platelet counts or the growth factor/cytokine levels and the potential clinical and radiographic regeneration outcomes due to APC were calculated after 3, 6, and 12 months.. The APC contained 2.2 x 10(6) platelets/mul, which was 7.9 times more than in the venous blood. Transforming growth factor-beta1 (TGF-beta1), insulin-like growth factor-I (IGF-I), platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) were found in the APC, whereas interleukin-1beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNFalpha), IL-4, and IL-10 were not detectable. The regression analysis showed a weak correlation between the platelet counts or the growth factor levels and the clinical and radiographic regeneration outcomes (r2

Topics: Absorbable Implants; Alveolar Bone Loss; Becaplermin; Biocompatible Materials; Bone Regeneration; Bone Substitutes; Calcium Phosphates; Cytokines; Epidermal Growth Factor; Follow-Up Studies; Guided Tissue Regeneration, Periodontal; Humans; Insulin-Like Growth Factor I; Intercellular Signaling Peptides and Proteins; Membranes, Artificial; Platelet Count; Platelet Transfusion; Platelet-Derived Growth Factor; Plateletpheresis; Proto-Oncogene Proteins c-sis; Transforming Growth Factor beta1; Transplantation, Autologous; Treatment Outcome; Vascular Endothelial Growth Factor A

Benign prostatic hyperplasia (BPH) is a condition that affects a significant population of older males, yet its pathogenesis is not clearly understood. This study was designed to give broader insight into the early development of BPH by looking at changes in growth factor production in the ventral prostate. To accomplish this, Sprague Dawley rats (n = 16, 250-300 g) were randomly divided into four equal groups. Three treatment groups were each implanted with ceramic drug delivery devices that were designed to deliver continuous physiologic doses of testosterone (T), dihydrotestosterone (DHT), and androstenedione (AED) for ninety-day duration. Immuno-histochemical analysis for epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) indicated whether these growth factors were involved in early processes of BPH induced by the delivery of androgens. Histopathological evaluation demonstrated increased positive reactivity for both EGF and bFGF in all steroid treated animals compared to controls. A similar trend was observed in the vascular endothelium. This information could be helpful in developing new methods for early diagnosis of BPH, but more importantly this knowledge provides the literature with clues about the cellular responses encountered at the initiation of the disease process.

Topics: Androgens; Androstenedione; Animals; Calcium Phosphates; Dihydrotestosterone; Drug Implants; Endothelium, Vascular; Epidermal Growth Factor; Fibroblast Growth Factors; Male; Prostate; Prostatic Hyperplasia; Rats; Reference Values; Testosterone