Biological Activation of Inert Ceramics: Recent Advances Using Tailored Self-Assembled Monolayers on Implant Ceramic Surfaces

High-strength ceramics as materials for medical implants have a long, research-intensive history. Yet, especially on applications where the ceramic components are in direct contact with the surrounding tissue, an unresolved issue is its inherent property of biological inertness. To combat this, several strategies have been investigated over the last couple of years. One promising approach investigates the technique of Self-Assembled Monolayers (SAM) and subsequent chemical functionalization to create a biologically active tissue-facing surface layer. Implementation of this would have a beneficial impact on several fields in modern implant medicine such as hip and knee arthroplasty, dental applications and related fields. This review aims to give a summarizing overview of the latest advances in this recently emerging field, along with thorough introductions of the underlying mechanism of SAMs and surface cell attachment mechanics on the cell side.     

Histological diversity in cholangiocellular carcinoma reflects the different cholangiocyte phenotypes

Cholangiocellular carcinoma (CC) originates from topographically heterogeneous cholangiocytes. The cylindrical mucin-producing cholangiocytes are located in large bile ducts and the cuboidal non-mucin-producing cholangiocytes are located in ductules containing bipotential hepatic progenitor cells (HPCs). We investigated the clinicopathological and molecular features of 85 resected CCs (14 hilar CCs [so-called Klatskin tumor], 71 intrahepatic CCs [ICCs] including 20 cholangiolocellular carcinomas [CLCs], which are thought to originate from HPCs]) and compared these with the different cholangiocyte phenotypes, including HPCs. Immunohistochemistry was performed with biliary/HPC and hepatocytic markers. Gene expression profiling was performed in different tumors and compared with nonneoplastic different cholangiocyte phenotypes obtained by laser microdissection. Invasion and cell proliferation assay were assessed using different types of CC cell lines: KMC-1, KMCH-1, and KMCH-2. Among 51 ICCs, 31 (60.8%) contained only mucin-producing CC features (muc-ICCs), whereas 39.2% displayed histological diversity: focal hepatocytic differentiation and ductular areas (mixed-ICCs). Clinicopathologically, muc-ICCs and hilar CCs showed a predominantly (peri-)hilar location, smaller tumor size, and more lymphatic and perineural invasion compared with mixed-ICCs and CLCs (predominantly peripheral location, larger tumor size, and less lymphatic and perineural invasion). Immunoreactivity was similar in muc-ICCs and hilar CCs and in mixed-ICCs and CLCs. S100P and MUC1 were significantly up-regulated in hilar CCs and muc-ICCs compared with mixed-ICCs and CLCs, whereas NCAM1 and ALB tended to be up-regulated in mixed-ICCs and CLCs compared with other tumors. KMC-1 showed significantly higher invasiveness than KMCH-1 and KMCH-2. Conclusion: Muc-ICCs had a clinicopathological, immunohistochemical, and molecular profile similar to that of hilar CCs (from mucin-producing cholangiocytes), whereas mixed-ICCs had a profile similar to that of CLCs (thought to be of HPC origin), possibly reflecting their respective cells of origin.     

Functional late outgrowth endothelial progenitors isolated from peripheral blood of burned patients

Background

Bioengineered skin substitutes are increasingly considered as a useful option for the treatment of full thickness burn injury. Their viability following grafting can be enhanced by seeding the skin substitute with late outgrowth endothelial progenitor cells (EPCs). However, it is not known whether autologous EPCs can be obtained from burned patients shortly after injury.

Methods

Late outgrowth EPCs were isolated from peripheral blood sampled obtained from 10 burned patients (extent 19.6 ± 10.3% TBSA) within the first 24 h of hospital admission, and from 7 healthy subjects. Late outgrowth EPCs were phenotyped in vitro.

Results

In comparison with similar cells obtained from healthy subjects, growing colonies from burned patients yielded a higher percentage of EPC clones (46 versus 17%, p = 0.013). Furthermore, EPCs from burned patients secreted more vascular endothelial growth factor (VEGF) into the culture medium than did their counterparts from healthy subjects (85.8 ± 56.2 versus 17.6 ± 14 pg/mg protein, p = 0.018). When injected to athymic nude mice 6 h after unilateral ligation of the femoral artery, EPCs from both groups of subjects greatly accelerated the reperfusion of the ischaemic hindlimb and increased the number of vascular smooth muscle cells.

Conclusions

The present study supports that, in patients with burns of moderate extension, it is feasible to obtain functional autologous late outgrowth EPCs from peripheral blood. These results constitute a strong incentive to pursue approaches based on using autotransplantation of these cells to improve the therapy of full thickness burns.