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The influence of autologous and heterologous extract of antimicrobial peptides on leukocytes isolated during titanium implant insertion in rabbit and ovine model

Zdziennicka Joanna, Szponder Tomasz, Latalski Michał, Żylińska Beata, Sobczyńska-Rak Aleksandra, Wessely-Szponder Joanna

Engineering of Biomaterials

2021

Vol. 24, no. 159

24--30

This study evaluated the in vitro leukocyte response to titanium implants in the presence of autologous or heterologous antimicrobial peptides extracts. Antimicrobial peptides (AMPs) appeared to be a new approach both against microorganisms and for regulation of inflammatory and repair processes. To evaluate their potential usefulness in regenerative medicine, we prepared different extracts of neutrophil-derived AMPs from rabbit, ovine or porcine blood which contained AMPs of different compositions, mainly defensins, cathelicidins and fragments thereof. Then, we assessed in vitro the influence of different AMPs extracts on the neutrophils and monocyte-derived macrophages (MDM) activity. For this purpose, these cells were obtained from experimental animals, rabbits, or sheep submitted to insertion of a titanium implant into the tibial defect. The cultured cells stimulation was autologous or heterologous, dependently on the AMPs extract origin and the experimental animal species. The neutrophil activity was assessed on the basis of the enzymes release from azurophilic and secondary granules and the free radicals generation. The MDM functional assessment was based on the NO and superoxide generation and arginase activity. Additionally, morphological changes were evaluated in the cell cultures. Our results indicated that the origin of AMPs extract is crucial for its activity. The autologous extracts stimulated anti-inflammatory responses, whereas the heterologous extracts displayed pro-inflammatory effect on neutrophils and macrophages. These results might be considered during the introduction of new preparations in regenerative medicine.

Preparation and preliminary in vivo studies of resorbable polymer modified with allogenic bone chips for guided bone regeneration and orthopedic implants

Szaraniec Barbara, Szponder Tomasz, Gryń Karol, Ambroziak Maciej, Gut Grzegorz, Koperski Łukasz, Chłopek Jan

Engineering of Biomaterials

2021

Vol. 24, no. 162

13--19

Composites made of resorbable polylactide modified with bone powder are part of the current search for implantable materials endowed with advantageous biomechanical functions, which make them suitable for orthopedics and traumatology applications. The bone additive containing active bone morphogenetic proteins (BMPs) and calcium phosphates introduced into the polymer matrix is to grant the implant with a biological activity. Subsequently, the resorbable matrix should get replaced with bone tissue. In order to avoid losing the osteoinductive properties of the designed material, it should be processed at low temperatures via physicochemical methods. This paper is devoted to the preparation and optimization of the composite production method suitable for biodegradable polymers and morphogenetic proteins along with the assessment of biocompatibility and biological properties of obtained materials. The tape-casting method was successfully applied. Resorbable polymer (medical poly-L-lactide, Purasorb PL38 by Purac) with 15 wt% of human bone powder (from tissue bank) were used to fabricate PLA-CP/BMPs composite implants. They were tested in in vivo studies that were performed in rabbit bone tissues. The results show a high biocompatibility of the material and good osteointegration with bone tissue.

Impact of a pulsed magnetic field on selected polymer implant materials

Szponder Tomasz, Stodolak-Zych Ewa, Polkowska Izabela, Sobczyńska-Rak Aleksandra

Acta of Bioengineering and Biomechanics

2019

Vol. 21, no. 1

87--96

Physiotherapy with the use of pulsed magnetic fields is one of the methods of activating the processes of bone healing and regeneration. Exposing materials serving as membranes in guided bone regeneration (GBR) or guided tissue regeneration (GTR) to magnetic fields is an effective model that allows to monitor changes in the material under the influence of the magnetic field. Methods: Materials engineering methods were used to verify the extent of material degradation resulting from magnetic field exposure in an aqueous environment. Changes in surface morphology were observed under an optical microscope and a scanning electron microscope (SEM). Changes in surface wettability were analysed in relation to the direct contact angle. Chemical structural changes were verified with the use of infrared spectroscopy (FTIR-ATR). Results: The PCL-based membrane materials underwent relatively moderate surface degradation (altered contact angle, changes in surface morphology), but the absence of observable FTIR-ATR spectral shifts evidenced material stability under the influence of magnetic field. More extensive degradation processes were observed in the case of PLDLA-based materials, whose surface character changed from hydrophilic to hydrophobic. The spectra revealed enhanced intensity of the chain terminal groups, provided that modifiers (nanometric SiO2 and TCP (water reservoir)) were present in the polymer matrix. Conclusions: The extent degradation in the polymer membrane was primarily dependent on the presence of aqueous environment, while the influence of the magnetic field on the analysed membrane materials was negligible. Therefore, GBR/GTR membrane implants can be considered to remain stable during rehabilitation with the use of alternating magnetic field.