Osteostatin-loaded bioceramics stimulate osteoblastic growth and differentiation

Parathyroid hormone-related protein (107-111) improves the bone regeneration potential of gelatin–glutaraldehyde biopolymer-coated hydroxyapatite

“…By using this method, the mean uptake of PTHrP (107-111) by these scaffolds after 24 h of loading was 60%, equivalent to 0.7 ng of peptide per mg of scaffold. Meanwhile, 80% of this amount was released to the surrounding medium within 1 h, and virtually 100% at 48 h. It was previously shown that minor amounts of this peptide (in the sub-nanomolar range) still sustained biological activity [18,23,25,26].…”

“…Four hours later, 1 ml samples of the cell-conditioned medium were added to a 24-well plate and the fluorescence intensity was measured using excitation and emission wavelengths of 540 and 620 nm, respectively. Following incubation with the tested materials for 4 days, the cells were washed with PBS and the alkaline phosphatase (ALP) activity was measured in cell extracts obtained with 0.1% Triton X-100 using p-nitrophenylphosphate as the substrate, as described previously [26,34]. The ALP activity was normalized to cell protein content, determined by the bicinchoninic acid (Thermo Scientific, Rockford, IL, USA) method with bovine serum albumin as standard.…”

“…Cell culture experiments were performed using the well-characterized mouse osteoblastic cell line MC3T3-E1 (subclone 4, CRL-2593; ATCC, Mannassas, VA), which responds to C-terminal PTHrP peptides [25,26,33,34]. The tested scaffolds were placed into each well of 6-or 24-well plates before cell seeding.…”

“…HA Glu scaffolds were loaded with synthetic PTHrP (107-111) (Bachem, Bubendorf, Switzerland) by soaking them in a solution of the peptide (at 100 nM) in 1 ml of phosphate-buffered saline (PBS) solution (pH 7.4) with constant shaking at 4°C for 24 h. Peptide release from the loaded material was assessed by including a radiotracer together with the cold peptide during PTHrP (107-111) loading, as described elsewhere [26]. The radioactivity released into the incubation medium was sequentially monitored by counting in a c-spectrometer.…”

“…In addition, the C-terminal 107-111 domain (also known as osteostatin) of PTHrP also exhibits osteogenic features in vitro, and stimulates bone accrual in vivo [17][18][19][20][21][22][23][24][25]. Of note, we recently showed that loading non-degradable Si-based ceramics with the latter pentapeptide gives them osteogenic and angiogenic features both in vitro and in vivo as implants in a cavitary defect in the rabbit femur [26][27][28][29]. These effects of osteostatin were thought to be due to its release into the local environment, because this type of ceramic elicits the formation of a fibrous capsule that hampers close contact between the implant and the surrounding tissue [27,29].…”