bioRxiv Science⌕ Search

Biology subjects

Buttgereit, F.

Publications and source records attributed to Buttgereit, F..

5 recordsLinked to original sources

Multi-Lab Testing of Early Preclinical Discoveries Identifies Promising Treatments

A fundamental challenge in drug development is the frequent failure of early laboratory research to translate into clinical benefit. One promising solution is to confirm findings from exploratory single-laboratory studies across multiple laboratories before clinical testing. We investigated this approach following the conduct of preclinical multi-laboratory studies across different fields of medicine. For this, we evaluated effect sizes, experimental rigor, and a set of criteria to identify determinants of confirmation success. When tested under increased rigor, only a fraction of multi-laboratory studies confirmed the initial results. The underlying effect size reduction was associated with outcome-relevant experimental differences between exploratory and confirmatory stages. In summary, multi-laboratory studies proved highly informative and served as an effective filter for promising treatments.

scientific communication and education↗

A Buprenorphine depot formulation provides effective sustained post-surgical analgesia for 72h in mouse femoral fracture models

Adequate pain management is essential for ethical and scientific reasons in animal experiments and should completely cover the period of expected pain without the need for frequent re-application. However, current depot formulations of Buprenorphine are only available in the USA and have limited duration of action. Recently, a new microparticulate Buprenorphine formulation (BUP-Depot) for sustained release has been developed as an alternative product within Europe. Pharmacokinetics indicate a potential effectiveness for about 72h. Here, we investigated whether the administration of the BUP-Depot ensures continuous and sufficient analgesia in two mouse femoral fracture models and could therefore serve as a potent alternative to the application of Tramadol via drinking water. Both protocols were examined for analgesic effectiveness, side effects on experimental readout, and effects on fracture healing outcomes in male and female C57BL/6N mice. The BUP-Depot provided effective analgesia for 72h, comparable to the effectiveness of Tramadol in drinking water. Fracture healing outcome was not different between analgesic regimes. The availability of a Buprenorphine depot formulation for laboratory animals in Europe would be a beneficial addition for extended pain relief in mice, thereby increasing animal welfare.

animal behavior and cognition↗

HIF-stabilization prevents delayed fracture healing

The initial phase of fracture healing decides on success of bone regeneration and is characterized by an inflammatory milieu and low oxygen tension (hypoxia). Negative interference with or prolongation of this fine-tuned initiation phase will ultimately lead to a delayed or incomplete healing such as non-unions which then requires an effective and gentle therapeutic intervention. Common reasons include a dysregulated immune response, immunosuppression or a failure in cellular adaptation to the inflammatory hypoxic milieu of the fracture gap and a reduction in vascularizing capacity by environmental noxious agents (e.g. rheumatoid arthritis, smoking). The hypoxia-inducible factor (HIF)-1α is responsible for the cellular adaptation to hypoxia, activating angiogenesis and supporting cell attraction and migration to the fracture gap. Here, we hypothesized that stabilizing HIF-1α could be a cost-effective and low-risk prevention strategy of fracture healing disorders. Therefore, we combined a well-known HIF-stabilizer – deferoxamine (DFO) – and a less known HIF-enhancer – macrophage migration inhibitory factor (MIF) – to synergistically induce improved fracture healing. Stabilization of HIF-1α enhanced calcification and osteogenic differentiation of MSCs in vitro. In vivo, the application of DFO with or without MIF during the initial healing phase accelerated callus mineralization and vessel formation in a clinically relevant mouse-osteotomy-model in a compromised healing setting. Our findings provide support for a promising preventive strategy towards bone healing disorders in patients with a higher risk due to e.g. delayed neovascularization by accelerating fracture healing using DFO and MIF to stabilize HIF-1α.Competing Interest StatementThe authors have declared no competing interest.View Full Text

bioengineering↗

An in vitro human-based fracture gap model - Mimicking the crosstalk between bone and immune cells

The interaction between the bone and immune cells plays a crucial role in bone pathologies such as disturbed fracture healing. After a trauma, the initially formed fracture hematoma in the fracture gap contains all important components (immune/stem cells, mediators) to directly induce bone regeneration and is therefore of great importance but most susceptible to negative influences. Thus, reliable in vitro models are needed to study the underlying mechanisms and to predict the efficiency of novel therapeutic approaches. Since common bioengineering approaches exclude the immune component, we introduce an in vitro 3D fracture gap model which combines scaffold-free bone-like constructs with a fracture hematoma model consisting of human peripheral blood (immune cells) and bone marrow-derived mesenchymal stromal cells. Our in vitro 3D fracture gap model provides all osteogenic cues to induce the initial bone healing processes, which were further promoted by applying the osteoinductive deferoxamine (DFO). Thus, we were able to distinctly mimic processes of the initial fracture phase and demonstrated the importance of including the crosstalk between bone and immune cells.

bioengineering↗

In vitro and in silico modeling of cellular and matrix-related changes during the early phase of osteoarthritis

ObjectiveUnderstanding the pathophysiological processes of osteoarthritis (OA) require adequate model systems. Although different in vitro or in vivo models have been described, further comprehensive approaches are needed to study specific parts of the disease. This study aimed to combine in vitro and in silico modeling to describe cellular and matrix-related changes during the early phase of OA. We developed an in vitro OA model based on scaffold-free cartilage-like constructs (SFCCs), which was mathematically modeled using a partial differential equation (PDE) system to resemble the processes during the onset of OA.\n\nDesignSFCCs were produced from mesenchymal stromal cells and analyzed weekly by histology and qPCR to characterize the cellular and matrix-related composition. To simulate the early phase of OA, SFCCs were treated with interleukin-1{beta} (IL-1{beta}), tumor necrosis factor (TNF) and examined after 3 weeks or cultivated another 3 weeks without inflammatory cytokines to validate the regeneration potential. Mathematical modeling was performed in parallel to the in vitro experiments.\n\nResultsSFCCs expressed cartilage-specific markers, and after stimulation an increased expression of inflammatory markers, matrix degrading enzymes, a loss of collagen II (Col-2) and a reduced cell density was observed which could be partially reversed by retraction of stimulation. Based on the PDEs, the distribution processes within the SFCCs, including those of IL-1{beta}, Col-2 degradation and cell number reduction was simulated.\n\nConclusionsBy combining in vitro and in silico methods, we aimed to develop a valid, efficient alternative approach to examine and predict disease progression and new therapeutic strategies.

bioengineering↗