Explore the vast range of titles available.

The development of biocompatible and precisely printable bioink addresses the growing demand for three-dimensional (3D) bioprinting applications in the field of tissue engineering. We developed a methacrylated photocurable silk fibroin (SF) bioink for digital light processing 3D bioprinting to generate structures with high mechanical stability and biocompatibility for tissue engineering applications. Procedure 1 describes the synthesis of photocurable methacrylated SF bioink, which takes 2 weeks to complete. Digital light processing is used to fabricate 3D hydrogels using the bioink (1.5 h), which are characterized in terms of methacrylation, printability, mechanical and rheological properties, and biocompatibility. The physicochemical properties of the bioink can be modulated by varying photopolymerization conditions such as the degree of methacrylation, light intensity, and concentration of the photoinitiator and bioink. The versatile bioink can be used broadly in a range of applications, including nerve tissue engineering through co-polymerization of the bioink with graphene oxide, and for wound healing as a sealant. Procedure 2 outlines how to apply 3D-printed SF hydrogels embedded with chondrocytes and turbinate-derived mesenchymal stem cells in one specific in vivo application, trachea tissue engineering, which takes 2–9 weeks. Park and colleagues describe the synthesis of methacrylated photocurable silk fibroin bioink for digital light processing 3D bioprinting as well as fabrication of biocompatible organ-mimicking hydrogel structures for trachea tissue engineering.

The present study compared changes in cuff pressure by head and neck position between high-volume low-pressure (HVLP) and taper-shaped (taper) cuffs in a prospective randomized clinical trial. Methods. Forty patients were intubated using tracheal tubes with either HVLP ( n = 20 ; HVLP group) or taper-shaped ( n = 20 ; Taper group) cuffs. Initial cuff pressure was adjusted to 15, 20, or 25 cmH2O in the neutral position. Cuff pressure was evaluated after changing the head and neck positions to flexion, extension, and rotation. Results. Cuff pressure significantly increased with flexion in both HVLP and Taper groups at all initial cuff pressures. It significantly increased with extension in the HVLP group, but not in the Taper group. Cuff pressure did not significantly differ with rotation in either group and was significantly smaller in the Taper group during flexion and extension than in the HVLP group, regardless of initial cuff pressure. Conclusion. Cuff pressure changes with head and neck flexion and extension were smaller in the Taper group than in the HVLP group. Our results highlight the potential for taper cuffs to prevent excessive cuff pressure increases with positional changes in the head and neck. This trial is registered with UMIN000016119.

Key Points A lumen arising de novo creates a space between or within cells where no space existed before. De novo lumen formation has been studied in several model systems. Despite apparent differences, there are many cell biological commonalities that now justify a unifying overview. A major mechanism of de novo lumen formation is the delivery of membrane material to the apical plasma membrane of the lumen-forming cell, which must be incorporated in a spatially structured manner. Lumen formation can be subdivided into three steps: determining the site of lumen initiation, enlarging the apical domain, and the maturation and stabilization of the lumen. The major cellular machineries needed for tube construction are cell polarity determinants, vesicle-trafficking systems and the cytoskeleton. Although there is currently a good understanding of how material is delivered to the apical membrane during the creation of tubes, an important open question is how the membrane is given its spatial structure. Recent studies suggest that mechanisms of de novo lumen formation in different systems — such as the zebrafish vasculature, C. elegans excretory cells, the D. melanogaster trachea and three-dimensional cultures of endothelial and MDCK cells — share some common features. They all involve expansion of the apical plasma membrane, vesicle transport and regulation of the microtubule and actin cytoskeletons. Many organs contain networks of epithelial tubes that transport gases or fluids. A lumen can be generated by tissue that enwraps a pre-existing extracellular space or it can arise de novo either between cells or within a single cell in a position where there was no space previously. Apparently distinct mechanisms of de novo lumen formation observed in vitro — in three-dimensional cultures of endothelial and Madin–Darby canine kidney (MDCK) cells — and in vivo — in zebrafish vasculature, Caenorhabditis elegans excretory cells and the Drosophila melanogaster trachea — in fact share many common features. In all systems, lumen formation involves the structured expansion of the apical plasma membrane through general mechanisms of vesicle transport and of microtubule and actin cytoskeleton regulation.

Organs have a distinctive yet often overlooked spatial arrangement in the body 1 – 5 . We propose that there is a logic to the shape of an organ and its proximity to its neighbours. Here, by using volumetric scans of many Drosophila melanogaster flies, we develop methods to quantify three-dimensional features of organ shape, position and interindividual variability. We find that both the shapes of organs and their relative arrangement are consistent yet differ between the sexes, and identify unexpected interorgan adjacencies and left–right organ asymmetries. Focusing on the intestine, which traverses the entire body, we investigate how sex differences in three-dimensional organ geometry arise. The configuration of the adult intestine is only partially determined by physical constraints imposed by adjacent organs; its sex-specific shape is actively maintained by mechanochemical crosstalk between gut muscles and vascular-like trachea. Indeed, sex-biased expression of a muscle-derived fibroblast growth factor-like ligand renders trachea sexually dimorphic. In turn, tracheal branches hold gut loops together into a male or female shape, with physiological consequences. Interorgan geometry represents a previously unrecognized level of biological complexity which might enable or confine communication across organs and could help explain sex or species differences in organ function. In fruit flies, three-dimensional organ arrangement is stereotypical, sexually dimorphic and actively maintained by muscle-vessel mechanochemical crosstalk.

Mucociliary clearance is a vital defense mechanism of the human airways, protecting against harmful particles and infections. When this process fails, it contributes to respiratory diseases like chronic obstructive pulmonary disease (COPD) and asthma. While advances in single-cell transcriptomics have revealed the complexity of airway composition, much of what we know about how airway structure impacts clearance relies on animal studies. This limits our ability to create accurate human-based models of airway diseases. Here we show that the airways in female rats and in humans exhibit species-specific differences in the distribution of ciliated and secretory cells as well as in ciliary beat, resulting in significantly higher clearance effectiveness in humans. We further reveal that standard lab-grown cultures exhibit lower clearance effectiveness compared to human airways, and we identify the underlying structural differences. By combining diverse experiments and physics-based modeling, we establish universal benchmarks to assess human airway function, interpret preclinical models, and better understand disease-specific impairments in mucociliary clearance. Mucociliary clearance is crucial for airway defense but its structure-function relationships in humans are not fully understood. Here, the authors show how airway epithelial structure impacts clearance by mapping cilia distribution, comparing human and rat airways, and developing quantitative models to assess function.

Aim The aim of this work is to analyze, by means of noninvasive monitoring, the clinical effects of high intraperitoneal pressure for enough time to insert the first trocar. Methods Sixty-seven patients without significant lung problems were randomly divided into groups P12 ( n  = 30, maximum intraperitoneal pressure 12 mmHg) and P20 ( n  = 37, maximum intraperitoneal pressure 20 mmHg). A Veress needle was inserted into the left hypochondrium for creation of pneumoperitoneum. The parameters evaluated were heart rate (HR, in bpm), arterial oxygen saturation (SaO 2 , expressed as percentage of hemoglobin saturated with oxygen), end-tidal CO 2 (ETCO 2 , in mmHg), mean arterial pressure (MAP, in mmHg), and intratracheal pressure (ITP, in cmH 2 O). Clinical parameters were evaluated in both groups at time point 0 (TP0, before CO 2 insufflation), time point 1 (TP1, when intraperitoneal pressure of 12 mmHg was reached in both groups), time point 2 (TP2, 5 min after reaching intraperitoneal pressure of 12 mmHg in group P12 and of 20 mmHg in group P20), and time point 3 (TP3, 10 min after reaching intraperitoneal pressure of 12 mmHg in group P12 and 10 min after TP1 in group P20, when intraperitoneal pressure decreased from 20 to 12 mmHg). Values outside of the normal range or occurrence of atypical phenomena suggestive of organic disease indicated clinical changes. Results Statistically significant differences were observed between the two groups regarding HR, MAP, ETCO 2 , and ITP. No significant clinical changes were observed. Conclusions Transitory, high intraperitoneal pressure (20 mmHg for 5 min) for insertion of the first trocar resulted in changes in HR, MAP, ETCO 2 , and ITP that were within the normal range, and no adverse clinical effects were observed. Therefore, the use of transitory, high intraperitoneal pressure is recommended to prevent iatrogenic injury during blind insertion of the first trocar. Nevertheless, it is not clear that this method would be safe in patients with moderate to severe chronic obstructive pulmonary disease.

In adult tissues, stem cells (SCs) reside in specialized niches, where they remain relatively stationary state until activated by injury. While migration is essential for regeneration, mechanisms guiding SCs towards injury sites remain poorly understood due to challenges in tracking them in vivo. Here, we present an experimental framework to monitor intestinal SC (ISC) movement in real time during early gut regeneration. We identify the Drosophila PDGF-VEGF-related receptor, Pvr, as a critical regulator of this process, with ISC-specific Pvr depletion strongly impairing migration and regeneration. The ligand, Pvf1, produced by gut-associated trachea after damage, serves as a guidance cue directing ISCs towards injury sites. Our work highlights a critical role of gut-trachea crosstalk in guiding ISC migration during regeneration. As neovascularization of injury sites is a key feature of tissue repair in both flies and mammals, these findings could have broader implications for regenerative processes across diverse adult tissues. Adult stem cells often reside in specialized niches that they exit upon injury. Here they show that in Drosophila, after damage the gut-associated trachea produces the PDGF-VEGF-related ligand Pvf1, which acts as a guidance cue directing ISC migration toward injury sites.

Organ functionalization is inherently complex and dynamic, involving multilayered tissue structures and continuous cellular remodeling. To address the clinical need for long-segment tracheal reconstruction, we propose a dynamic tissue engineering (DTE) strategy using a bio-adaptive physical hydrogel (BP-Gel) to emulate native tracheal development and enable dynamic regeneration of key tissue components. Here we show that chondrocytes cultured within BP-Gel form cartilage rings through an embryo-like chondrification process, during which the gel’s percolation network adapts to cell migration and aggregation. The resulting cartilage exhibits a native-like multilayered morphology that enhances mechanical stability and resists degradation. Before transplantation, BP-Gel loaded with anti-inflammatory cytokines (IL-Gel) is introduced into inter-ring spaces to suppress inflammation and promote vascularization and epithelial maturation. In a rabbit tracheal defect model, this strategy reconstructs a functional trachea mimicking native structure and physiology, offering a promising, clinically relevant route to tracheal reconstruction. Tracheal defects lack effective long-segment repair solutions. Here, authors develop a bio-adaptive hydrogel strategy that guides cartilage, vascular, and epithelial regeneration to reconstruct a functional, long-segment trachea.

Motile cilia can beat with distinct patterns, but how motility variations are regulated remain obscure. Here, we have studied the role of the coiled-coil protein CFAP53 in the motility of different cilia-types in the mouse. While node (9+0) cilia of Cfap53 mutants were immotile, tracheal and ependymal (9+2) cilia retained motility, albeit with an altered beat pattern. In node cilia, CFAP53 mainly localized at the base (centriolar satellites), whereas it was also present along the entire axoneme in tracheal cilia. CFAP53 associated tightly with microtubules and interacted with axonemal dyneins and TTC25, a dynein docking complex component. TTC25 and outer dynein arms (ODAs) were lost from node cilia, but were largely maintained in tracheal cilia of Cfap53 -/- mice. Thus, CFAP53 at the base of node cilia facilitates axonemal transport of TTC25 and dyneins, while axonemal CFAP53 in 9+2 cilia stabilizes dynein binding to microtubules. Our study establishes how differential localization and function of CFAP53 contributes to the unique motion patterns of two important mammalian cilia-types.