Biphasic bone substitutes (BBS) are nowadays established biomaterials. Through their constant development even natural components like hyaluronic acid (HY) are added to improve both their handling and also their regenerative properties. However, low knowledge exists regarding the consequences of the HY addition for their biocompatibility and the inflammatory tissue reactions. Thus, the present study was conducted aiming to analyze the influence of two different amounts of high molecular weight HY (HMWHY) combined with a BBS on the in vitro biocompatibility and the in vivo tissue reaction. Established in vitro procedures using L929 cells were used for cytocompatibility analyses under the test conditions of DIN EN:ISO 10993-5. For the in vivo study part, calvarial defects were created in 20 Wistar rats and subsequently filled with the BBS and the BBS combined with two different HMWHY amounts, i.e., BBS+HY(L) and BBS+HY(H). As controls empty defects were used. Established histological, immunohistochemical and histomorphometrical methods were applied to analyze the tissue reactions to the three different materials, including the induction of pro- and anti-inflammatory macrophages and multinucleated giant cells (BMGCs). The in vitro results showed that none of the materials or compositions caused biological damages to the L929 cells and can considered to be non-toxic. The in vivo results showed that only the addition of high doses of HY to a biphasic bone substitute significantly decreases the occurrence of proinflammatory macrophages (* p < 0.05) comparable to the numbers found in the control group, while no significant differences within the three study groups for M2-macrophages nor BMGCs were detected. In conclusion, the addition of different amounts of HMWHY does not seem to affect the inflammation response to the BBS while improving the material handling properties.

The Mononuclear Phagocyte System includes monocytes, macrophages, some dendritic cells and multinuclear giant cells. These cell populations display marked heterogeneity depending on their differentiation from embryonic and bone marrow haematopoietic progenitors, tissue location and activation. They contribute to tissue homeostasis by interacting with local and systemic immune and non-immune cells, through trophic, clearance and cytocidal functions. During evolution they contributed to innate host defense before effector mechanisms of specific adaptive immunity emerged. Mouse macrophages appear at midgestation and are distributed throughout the embryo to facilitate organogenesis and clear cells undergoing programmed cell death. Yolk sac-, AGM- and foetal liver-derived tissue resident macrophages persist throughout postnatal and adult life, supplemented by bone marrow-derived blood monocytes, as required after injury and infection. Nobel awards to Elie Metchnikoff and Paul Ehrlich in 1908 drew attention to cellular phagocytic and humoral immunity, respectively. In 2011, prizes were awarded to Jules Hoffmann and Bruce Beutler for contributions to innate immunity and to Ralph Steinman for discovery of Dendritic Cells and their role in antigen presentation to T lymphocytes. We trace milestones in the history of mononuclear phagocyte research from the perspective of Nobel awards bearing directly and indirectly on their role in cellular immunity.

Cancer is a complex and devastating disease that has engaged scientists and researchers for decades. Despite tremendous efforts, previous hypotheses about cancer development have not achieved significant breakthroughs. Evolutionary Cancer Cell Biology (ECCB) is a novel and emerging branch of oncological science that provides an evolutionary perspective on the origin of cancer. It reveals that the cancer genome evolved hundreds of millions of years ago, long before multicellular organisms such as metazoans and humans emerged. ECCB aims to unify all evolutionary insights, hypotheses, and theories into a cohesive framework. It investigates the intricate relationship between cancer genomics and ancient pre-metazoan genes that emerge when normal cells transform into cancer cells. It challenges the conventional wisdom of cancer research by suggesting that cancer could arise through intrinsic cellular mechanisms without genetic alterations and mutations. Furthermore, it postulates that somatic mutations are only secondary, downstream events in the process of oncogenesis.