@article{ae8aabc7af14427e8624f6a810ad1413,
title = "A culture model to analyze the acute biomaterial-dependent reaction of human primary neutrophils in vitro",
abstract = "Neutrophils play a pivotal role in orchestrating the immune system response to biomaterials, the onset and resolution of chronic inflammation, and macrophage polarization. However, the neutrophil response to biomaterials and the consequent impact on tissue engineering approaches is still scarcely understood. Here, we report an in vitro culture model that comprehensively describes the most important neutrophil functions in the light of tissue repair. We isolated human primary neutrophils from peripheral blood and exposed them to a panel of hard, soft, naturally- and synthetically-derived materials. The overall trend showed increased neutrophil survival on naturally derived constructs, together with higher oxidative burst, decreased myeloperoxidase and neutrophil elastase and decreased cytokine secretion compared to neutrophils on synthetic materials. The culture model is a step to better understand the immune modulation elicited by biomaterials. Further studies are needed to correlate the neutrophil response to tissue healing and to elucidate the mechanism triggering the cell response and their consequences in determining inflammation onset and resolution.",
author = "Wesdorp, {Marinus A.} and Andrea Schwab and Bektas, {Ezgi Irem} and Roberto Narcisi and David Eglin and Stoddart, {Martin J.} and {Van Osch}, {Gerjo J.V.M.} and Matteo D'Este",
note = "Funding Information: The proposed approach analyzing multiple neutrophil functions is of benefit towards understanding the possible consequences of biomaterial properties for tissue repair. Based on our results, metabolic activity of neutrophils was highest in PCL and TCP after 1 and 3 h, in conjunction with elevated levels of LDH release in PCL, TCP and PVA and lower cell viability after 24 h. Serum was not added to cell culture media to prevent possible effects of serum proteins on neutrophil activation, that could mask the specific biomaterials effect. The role of serum in influencing the interaction between neutrophils and biomaterials is a crucial point requiring further investigation. Previous studies investigated the effects of physicochemical properties like size, shape, surface topography, wettability and surface charge on neutrophils, suggesting that these features might play a role in neutrophil survival and activation [14]. The low viability of neutrophils on PCL might be due to low adhesion on the hydrophobic surface because of the serum-free conditions, implying lower levels of protein coating on all substrates. Interestingly, in presence of serum hydrophobic surfaces are prone to marked protein absorption, fostering survival or activation of neutrophils [14,30]. Although TCP is also intrinsically hydrophobic, plates for tissue culture are surface treated to increase hydrophilicity and thereby cell adhesion. Unlike for other cell types, identifying a standard substrate for neutrophil cell culture to study their interaction with materials is not straightforward, because every material will inevitably influence neutrophils activation. Consequently, our experiments and data analysis compared the response on different materials rather than against a chosen standard. After 24 h the survival of neutrophils on a hydrophilic PVA (hydrogel) surface was lower than on hydrogels consisting of naturally derived macromolecules with matched mechanical properties. Therefore, chemical composition of materials also plays a role in neutrophil survival. This difference in response is further supported by the elevated levels of LDH that were found in the supernatant of neutrophils cultured on the aforementioned synthetic materials. After 24 h, LDH levels were significantly increased indicating higher levels of cell membrane damage or cell death for neutrophils cultured on synthetic materials in comparison to naturally derived materials. The high levels of LDH in PCL, PVA and TCP indicate that the prevalent form of cell death is necrosis rather than apoptosis or other types of programmed cell death. In apoptosis the cell-membrane is still intact in contrast with necrosis where a damaged cell-membrane results in the release of LDH [31]. Whether a cell will undergo necrosis, or the more regulated apoptosis depends on what stimulus the neutrophil receives [32,33]. Neutrophil death by necrosis is usually a trigger for inflammation and a major cause of tissue damage [33,34]. This may fuel an unwanted inflammatory response after the implantation of a biomaterial. After 24 h on the natural materials, almost all neutrophils were alive and released little LDH indicating that they might be in an activated but still living state.The authors express thanks to Dr. Milena Sokolowska, Swiss Institute of Allergy and Asthma Research, for valuable input and to introduce us to the Olink{\textregistered} technique, and to Dr. Anja Heider from the same institution for support with the Olink{\textregistered} analysis, and Dr Claire Duchez, INSERM, U1059 SAINBIOSE for valuable feedback. This work received financial support from the AO Foundation through the Osteochondral Defect Collaborative Research Program and through an AO CMF grant. We would like to thank all volunteers who donated their blood. Funding Information: The authors express thanks to Dr. Milena Sokolowska, Swiss Institute of Allergy and Asthma Research, for valuable input and to introduce us to the Olink{\textregistered} technique, and to Dr. Anja Heider from the same institution for support with the Olink{\textregistered} analysis, and Dr Claire Duchez, INSERM, U1059 SAINBIOSE for valuable feedback. This work received financial support from the AO Foundation through the Osteochondral Defect Collaborative Research Program and through an AO CMF grant. We would like to thank all volunteers who donated their blood. Publisher Copyright: {\textcopyright} 2022 The Authors",
year = "2023",
month = feb,
doi = "10.1016/j.bioactmat.2022.05.036",
language = "English",
volume = "20",
pages = "627--637",
journal = "Bioactive Materials",
issn = "2452-199X",
publisher = "KeAi Communications Co",
}