Incorporation of metal-doped silicate microparticles into collagen scaffolds combines chemical and architectural cues for endochondral bone healing.

Regeneration of large bone defects remains a clinical challenge until today. While existing biomaterials are predominantly addressing bone healing via direct, intramembranous ossification (IO), bone tissue formation via a cartilage phase, so-called endochondral ossification (EO) has been shown to be a promising alternative strategy. However, pure biomaterial approaches for EO induction are sparse and the knowledge how material components can have bioactive contribution to the required cartilage formation is limited.

Collagen Fibrils Mechanically Contribute to Tissue Contraction in an In Vitro Wound Healing Scenario.

Wound contraction is an ancient survival mechanism of vertebrates that results from tensile forces supporting wound closure. So far, tissue tension was attributed to cellular forces produced by tissue-resident (myo-)fibroblasts alone. However, difficulties in explaining pathological deviations from a successful healing path motivate the exploration of additional modulatory factors.

A biomaterial with a channel-like pore architecture induces endochondral healing of bone defects.

Biomaterials developed to treat bone defects have classically focused on bone healing via direct, intramembranous ossification. In contrast, most bones in our body develop from a cartilage template via a second pathway called endochondral ossification. The unsolved clinical challenge to regenerate large bone defects has brought endochondral ossification into discussion as an alternative approach for bone healing.

Mesoscale substrate curvature overrules nanoscale contact guidance to direct bone marrow stromal cell migration.

The intrinsic architecture of biological tissues and of implanted biomaterials provides cells with large-scale geometrical cues. To understand how cells are able to sense and respond to complex structural environments, a deeper insight into the cellular response to multi-scale and conflicting geometrical cues is needed. In this study, we subjected human bone marrow stromal cells (hBMSCs) to mesoscale cylindrical surfaces (diameter 250-5000 µm) and nanoscale collagen fibrils (diameter 100-200 nm) that were aligned perpendicular to the cylinder axis.

Surface Curvature Differentially Regulates Stem Cell Migration and Differentiation via Altered Attachment Morphology and Nuclear Deformation.

Signals from the microenvironment around a cell are known to influence cell behavior. Material properties, such as biochemical composition and substrate stiffness, are today accepted as significant regulators of stem cell fate. The knowledge of how cell behavior is influenced by 3D geometric cues is, however, strongly limited despite its potential relevance for the understanding of tissue regenerative processes and the design of biomaterials.

GLP-1 plays a limited role in improved glycemia shortly after Roux-en-Y gastric bypass: a comparison with intensive lifestyle modification.

Rapid glycemic improvements following Roux-en-Y gastric bypass (RYGB) are frequently attributed to the enhanced GLP-1 response, but causality remains unclear. To determine the role of GLP-1 in improved glucose tolerance after surgery, we compared glucose and hormonal responses to a liquid meal test in 20 obese participants with type 2 diabetes mellitus who underwent RYGB or nonsurgical intensive lifestyle modification (ILM) (n = 10 per group) before and after equivalent short-term weight reduction. The GLP-1 receptor antagonist exendin(9-39)-amide (Ex-9) was administered, in random order and in double-blinded fashion, with saline during two separate visits after equivalent weight loss.

Fundamentals of endoscopic surgery: creation and validation of the hands-on test.

Background: The Fundamentals of Endoscopic Surgery™ (FES) program consists of online materials and didactic and skills-based tests. All components were designed to measure the skills and knowledge required to perform safe flexible endoscopy. The purpose of this multicenter study was to evaluate the reliability and validity of the hands-on component of the FES examination, and to establish the pass score.

Crosstalk between immune cells and mesenchymal stromal cells in a 3D bioreactor system.

Introduction: Mesenchymal stromal cells (MSC), known for their high immune modulatory capacity are promising tools for several cell-based therapies. To better mimic the in vivo situation of MSC interactions with immune cells, we applied an artificial lymph node (ALN)-bioreactor culture system combining a miniaturized perfusion bioreactor with a 3D matrix-based cell culture of immune competent cells forming micro-organoids.

Methods: Rat lymph node cells and allogeneic bone marrow-derived MSCs were seeded in a 20:1 ratio within the agarose matrix of the ALN-reactor.

The impact of substrate stiffness and mechanical loading on fibroblast-induced scaffold remodeling.

Fibroblasts as many other cells are known to form, contract, and remodel the extracellular matrix (ECM). The presented study aims to gain an insight into how mechanical boundary conditions affect the production of ECM components, their remodeling, and the feedback of the altered mechanical cell environment on these processes. The influence of cyclic mechanical loading (f=1 Hz, 10% axial compression) and scaffold stiffness (E=1.

Obstructive sleep apnea in patients undergoing bariatric surgery--a tertiary center experience.

Background: The patient population that is evaluated for bariatric surgery is characterized by a very high body mass index (BMI). Since obesity is the most important risk factor for obstructive sleep apnea (OSA), sleep disordered breathing is highly prevalent in this population. If undiagnosed before bariatric surgery, untreated OSA can lead to perioperative and postoperative complications.