@article{WagenbrennerHeinzHorasetal.2020, author = {Wagenbrenner, Mike and Heinz, Tizian and Horas, Konstantin and Jakuscheit, Axel and Arnholdt, Joerg and Mayer-Wagner, Susanne and Rudert, Maximilian and Holzapfel, Boris M. and Weißenberger, Manuel}, title = {Impact of Tranexamic Acid on Chondrocytes and Osteogenically Differentiated Human Mesenchymal Stromal Cells (hMSCs) In Vitro}, series = {Journal of Clinical Medicine}, volume = {9}, journal = {Journal of Clinical Medicine}, number = {12}, issn = {2077-0383}, doi = {10.3390/jcm9123880}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219410}, year = {2020}, abstract = {The topical application of tranexamic acid (TXA) helps to prevent post-operative blood loss in total joint replacements. Despite these findings, the effects on articular and periarticular tissues remain unclear. Therefore, this in vitro study examined the effects of varying exposure times and concentrations of TXA on proliferation rates, gene expression and differentiation capacity of chondrocytes and human mesenchymal stromal cells (hMSCs), which underwent osteogenic differentiation. Chondrocytes and hMSCs were isolated and multiplied in monolayer cell cultures. Osteogenic differentiation of hMSCs was induced for 21 days using a differentiation medium containing specific growth factors. Cell proliferation was analyzed using ATP assays. Effects of TXA on cell morphology were examined via light microscopy and histological staining, while expression levels of tissue-specific genes were measured using semiquantitative RT-PCR. After treatment with 50 mg/mL of TXA, a decrease in cell proliferation rates was observed. Furthermore, treatment with concentrations of 20 mg/mL of TXA for at least 48 h led to a visible detachment of chondrocytes. TXA treatment with 50 mg/mL for at least 24 h led to a decrease in the expression of specific marker genes in chondrocytes and osteogenically differentiated hMSCs. No significant effects were observed for concentrations beyond 20 mg/mL of TXA combined with exposure times of less than 24 h. This might therefore represent a safe limit for topical application in vivo. Further research regarding in vivo conditions and effects on hMSC functionality are necessary to fully determine the effects of TXA on articular and periarticular tissues.}, language = {en} } @article{WagenbrennerHeinzHorasetal.2020, author = {Wagenbrenner, Mike and Heinz, Tizian and Horas, Konstantin and Jakuscheit, Axel and Arnholdt, J{\"o}rg and Hermann, Marietta and Rudert, Maximilian and Holzapfel, Boris M. and Steinert, Andre F. and Weißenberger, Manuel}, title = {The human arthritic hip joint is a source of mesenchymal stromal cells (MSCs) with extensive multipotent differentiation potential}, series = {BMC Musculoskeletal Disorders}, volume = {21}, journal = {BMC Musculoskeletal Disorders}, number = {1}, doi = {10.1186/s12891-020-03340-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229497}, year = {2020}, abstract = {Background While multiple in vitro studies examined mesenchymal stromal cells (MSCs) derived from bone marrow or hyaline cartilage, there is little to no data about the presence of MSCs in the joint capsule or the ligamentum capitis femoris (LCF) of the hip joint. Therefore, this in vitro study examined the presence and differentiation potential of MSCs isolated from the bone marrow, arthritic hyaline cartilage, the LCF and full-thickness samples of the anterior joint capsule of the hip joint. Methods MSCs were isolated and multiplied in adherent monolayer cell cultures. Osteogenesis and adipogenesis were induced in monolayer cell cultures for 21 days using a differentiation medium containing specific growth factors, while chondrogenesis in the presence of TGF-ss1 was performed using pellet-culture for 27 days. Control cultures were maintained for comparison over the same duration of time. The differentiation process was analyzed using histological and immunohistochemical stainings as well as semiquantitative RT-PCR for measuring the mean expression levels of tissue-specific genes. Results This in vitro research showed that the isolated cells from all four donor tissues grew plastic-adherent and showed similar adipogenic and osteogenic differentiation capacity as proven by the histological detection of lipid droplets or deposits of extracellular calcium and collagen type I. After 27 days of chondrogenesis proteoglycans accumulated in the differentiated MSC-pellets from all donor tissues. Immunohistochemical staining revealed vast amounts of collagen type II in all differentiated MSC-pellets, except for those from the LCF. Interestingly, all differentiated MSCs still showed a clear increase in mean expression of adipogenic, osteogenic and chondrogenic marker genes. In addition, the examination of an exemplary selected donor sample revealed that cells from all four donor tissues were clearly positive for the surface markers CD44, CD73, CD90 and CD105 by flow cytometric analysis. Conclusions This study proved the presence of MSC-like cells in all four examined donor tissues of the hip joint. No significant differences were observed during osteogenic or adipogenic differentiation depending on the source of MSCs used. Further research is necessary to fully determine the tripotent differentiation potential of cells isolated from the LCF and capsule tissue of the hip joint.}, language = {en} } @article{ArnholdtKamawalHorasetal.2020, author = {Arnholdt, J{\"o}rg and Kamawal, Yama and Horas, Konstantin and Holzapfel, Boris M. and Gilbert, Fabian and Ripp, Axel and Rudert, Maximilian and Steinert, Andre F.}, title = {Accurate implant fit and leg alignment after cruciate-retaining patient-specific total knee arthroplasty}, series = {BMC Musculoskeletal Disorders}, volume = {21}, journal = {BMC Musculoskeletal Disorders}, doi = {10.1186/s12891-020-03707-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230012}, year = {2020}, abstract = {Background For improved outcomes in total knee arthroplasty (TKA) correct implant fitting and positioning are crucial. In order to facilitate a best possible implant fitting and positioning patient-specific systems have been developed. However, whether or not these systems allow for better implant fitting and positioning has yet to be elucidated. For this reason, the aim was to analyse the novel patient-specific cruciate retaining knee replacement system iTotal (TM) CR G2 that utilizes custom-made implants and instruments for its ability to facilitate accurate implant fitting and positioning including correction of the hip-knee-ankle angle (HKA). Methods We assessed radiographic results of 106 patients who were treated with the second generation of a patient-specific cruciate retaining knee arthroplasty using iTotal\(^{TM}\) CR G2 (ConforMIS Inc.) for tricompartmental knee osteoarthritis (OA) using custom-made implants and instruments. The implant fit and positioning as well as the correction of the mechanical axis (hip-knee-ankle angle, HKA) and restoration of the joint line were determined using pre- and postoperative radiographic analyses. Results On average, HKA was corrected from 174.4 degrees +/- 4.6 degrees preoperatively to 178.8 degrees +/- 2.2 degrees postoperatively and the coronal femoro-tibial angle was adjusted on average 4.4 degrees. The measured preoperative tibial slope was 5.3 degrees +/- 2.2 degrees (mean +/- SD) and the average postoperative tibial slope was 4.7 degrees +/- 1.1 degrees on lateral views. The joint line was well preserved with an average modified Insall-Salvati index of 1.66 +/- 0.16 pre- and 1.67 +/- 0.16 postoperatively. The overall accuracy of fit of implant components was decent with a measured medial overhang of more than 1 mm (1.33 mm +/- 0.32 mm) in 4 cases only. Further, a lateral overhang of more than 1 mm (1.8 mm +/- 0.63) (measured in the anterior-posterior radiographs) was observed in 11 cases, with none of the 106 patients showing femoral notching. Conclusion The patient-specific iTotal\(^{TM}\) CR G2 total knee replacement system facilitated a proper fitting and positioning of the implant components. Moreover, a good restoration of the leg axis towards neutral alignment was achieved as planned. Nonetheless, further clinical follow-up studies are necessary to validate our findings and to determine the long-term impact of using this patient- specific system.}, language = {en} } @article{JakubietzSchmidtHolzapfeletal.2020, author = {Jakubietz, Rafael G. and Schmidt, Karsten and Holzapfel, Boris M. and Meffert, Rainer H. and Jakubietz, Michael G.}, title = {Pedicled perforator flaps for mid-tibial soft tissue reconstruction in medically compromised patients}, series = {JPRAS Open}, volume = {24}, journal = {JPRAS Open}, doi = {10.1016/j.jpra.2020.02.002}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229473}, pages = {47-55}, year = {2020}, abstract = {Background: The soft tissue of the central pretibial area is difficult to reconstruct often requiring free tissue transfer. Especially medi- cally compromised patients are not ideal candidates for free tissue transfer and may benefit from expeditiously harvested local flaps with limited donor site morbidity. As muscle flaps are rare, pedi- cled flaps based on lateral perforators represent an alternative as the arc of rotation can often be limited to 90 °. Material and Methods: A retrospective analysis of patient data was conducted to identify patients over the age of 60 years with comor- bidities that underwent pretibial soft tissue reconstruction with a single-pedicle perforator flap. Patient demographics, size and cause of the defect, flap dimension, arc of rotation and complications were recorded. Results: Five patients with an average age of 71.4 years were in- cluded. The arc of rotation was 69 °, all flaps healed. There were two recurrences of osteomyelitis. Conclusion: Lateral perforators originating from the anterior tib- ial artery or peroneal artery are adequate source vessels for single pedicled perforator flaps even in medically compromised patients. A perforator located proximal to the defect allows limiting the arcof rotation to less than 90 °, which increases the safety of the flap. Patients benefit from a simple procedure without a microvascular anastomosis and a donor site confined to one extremity}, language = {en} } @article{WeissenbergerWeissenbergerWagenbrenneretal.2020, author = {Weissenberger, Manuel and Weissenberger, Manuela H. and Wagenbrenner, Mike and Heinz, Tizian and Reboredo, Jenny and Holzapfel, Boris M. and Rudert, Maximilian and Groll, J{\"u}rgen and Evans, Christopher H. and Steinert, Andre F.}, title = {Different types of cartilage neotissue fabricated from collagen hydrogels and mesenchymal stromal cells via SOX9, TGFB1 or BMP2 gene transfer}, series = {PLoS One}, volume = {15}, journal = {PLoS One}, number = {8}, doi = {10.1371/journal.pone.0237479}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230494}, year = {2020}, abstract = {Objective As native cartilage consists of different phenotypical zones, this study aims to fabricate different types of neocartilage constructs from collagen hydrogels and human mesenchymal stromal cells (MSCs) genetically modified to express different chondrogenic factors. Design Human MSCs derived from bone-marrow of osteoarthritis (OA) hips were genetically modified using adenoviral vectors encoding sex-determining region Y-type high-mobility-group-box (SOX)9,transforming growth factor beta (TGFB) 1or bone morphogenetic protein (BMP) 2cDNA, placed in type I collagen hydrogels and maintained in serum-free chondrogenic media for three weeks. Control constructs contained unmodified MSCs or MSCs expressing GFP. The respective constructs were analyzed histologically, immunohistochemically, biochemically, and by qRT-PCR for chondrogenesis and hypertrophy. Results Chondrogenesis in MSCs was consistently and strongly induced in collagen I hydrogels by the transgenesSOX9,TGFB1andBMP2as evidenced by positive staining for proteoglycans, chondroitin-4-sulfate (CS4) and collagen (COL) type II, increased levels of glycosaminoglycan (GAG) synthesis, and expression of mRNAs associated with chondrogenesis. The control groups were entirely non-chondrogenic. The levels of hypertrophy, as judged by expression of alkaline phosphatase (ALP) and COL X on both the protein and mRNA levels revealed different stages of hypertrophy within the chondrogenic groups (BMP2>TGFB1>SOX9). Conclusions Different types of neocartilage with varying levels of hypertrophy could be generated from human MSCs in collagen hydrogels by transfer of genes encoding the chondrogenic factorsSOX9,TGFB1andBMP2. This technology may be harnessed for regeneration of specific zones of native cartilage upon damage.}, language = {en} } @article{HorasvanHerckMaieretal.2020, author = {Horas, Konstantin and van Herck, Ulrike and Maier, Gerrit S. and Maus, Uwe and Harrasser, Norbert and Jakob, Franz and Weissenberger, Manuel and Arnholdt, J{\"o}rg and Holzapfel, Boris M. and Rudert, Maximilian}, title = {Does vitamin D deficiency predict tumour malignancy in patients with bone tumours? Data from a multi-center cohort analysis}, series = {Journal of Bone Oncology}, volume = {25}, journal = {Journal of Bone Oncology}, doi = {10.1016/j.jbo.2020.100329}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230314}, year = {2020}, abstract = {Vitamin D deficiency is a global health concern that is estimated to afflict over one billion people globally. The major role of vitamin D is that of a regulator of calcium and phosphate metabolism, thus, being essential for proper bone mineralisation. Concomitantly, vitamin D is known to exert numerous extra-skeletal actions. For example, it has become evident that vitamin D has direct anti-proliferative, pro-differentiation and pro-apoptotic actions on cancer cells. Hence, vitamin D deficiency has been associated with increased cancer risk and worse prognosis in several malignancies. We have recently demonstrated that vitamin D deficiency promotes secondary cancer growth in bone. These findings were partly attributable to an increase in bone remodelling but also through direct effects of vitamin D on cancer cells. To date, very little is known about vitamin D status of patients with bone tumours in general. Thus, the objective of this study was to assess vitamin D status of patients with diverse bone tumours. Moreover, the aim was to elucidate whether or not there is an association between pre-diagnostic vitamin D status and tumour malignancy in patients with bone tumours. In a multi-center analysis, 25(OH)D, PTH and calcium levels of 225 patients that presented with various bone tumours between 2017 and 2018 were assessed. Collectively, 76\% of all patients had insufficient vitamin D levels with a total mean 25(OH)D level of 21.43 ng/ml (53.58 nmol/L). In particular, 52\% (117/225) of patients were identified as vitamin D deficient and further 24\% of patients (55/225) were vitamin D insufficient. Notably, patients diagnosed with malignant bone tumours had significantly lower 25(OH)D levels than patients diagnosed with benign bone tumours [19.3 vs. 22.75 ng/ml (48.25 vs. 56.86 nmol/L); p = 0.04). In conclusion, we found a widespread and distressing rate of vitamin D deficiency and insufficiency in patients with bone tumours. However, especially for patients with bone tumours sufficient vitamin D levels seem to be of great importance. Thus, we believe that 25(OH)D status should routinely be monitored in these patients. Collectively, there should be an increased awareness for physicians to assess and if necessary correct vitamin D status of patients with bone tumours in general or of those at great risk of developing bone tumours.}, language = {en} }