Investigation of predictors for in-hospital death or long-term hospitalization in community-acquired pneumonia with risk factors for aspiration

Background

It is known that the mortality of pneumonia in patients with risk factors for aspiration is worse than that in those without these risk factors. However, it is still unknown which risk factors for aspiration predict prognosis. Therefore, we aimed to determine which risk factors for aspiration are associated with death or prolonged hospitalization.

Methods

We prospectively followed patients with community-acquired pneumonia at a single hospital providing acute to chronic care in Japan until they died or were discharged. Patients at any risk of aspiration were included. The associations between pneumonia severity, individual risk factors for aspiration, and in-hospital death or prolonged hospitalization were investigated. Overall survival was estimated by the Kaplan - Meier method, and the factors associated with in-hospital death or prolonged hospitalization were investigated by multivariate analysis using factors selected by a stepwise method.

Results

In total, 765 patients with pneumonia and risk factors for aspiration were recruited. One hundred and ten patients deceased, and 259 patients were hospitalized over 27 days. In-hospital death increased as the number of risk factors for aspiration increased. In the multivariate analysis, male, impaired consciousness, acidemia, elevated blood urea nitrogen, and bedridden status before the onset of pneumonia were associated with in-hospital death (odds ratio [OR]: 2.5, 2.5, 3.6, 3.1, and 2.6; 95% confidence interval [CI]: 1.6-4.1, 1.4-4.2, 1.6-8.0, 1.9-5.0, and 1.6-4.2 respectively). In the Cox regression analysis, these factors were also associated with in-hospital death. None of the vital signs at admission were associated. Tachycardia, elevated blood urea nitrogen, hyponatremia, and bedridden status were associated with hospitalization for >27 days (OR: 4.1, 2.3, 4.3, and 2.9; 95% CI: 1.3-12.9, 1.5-3.4, 2.0-9.4, and 2.0-4.0, respectively).

Conclusions

Blood sampling findings and bedridden status are useful for predicting in-hospital mortality and long-term hospitalization in patients with pneumonia and any risk factor for aspiration.

Intramuscular injection of mesenchymal stem cells augments basal muscle protein synthesis after bouts of resistance exercise in male mice

Skeletal muscle mass is critical for activities of daily living. Resistance training maintains or increases muscle mass, and various strategies maximize the training adaptation. Mesenchymal stem cells (MSCs) are multipotent cells with differential potency in skeletal muscle cells and the capacity to secrete growth factors. However, little is known regarding the effect of intramuscular injection of MSCs on basal muscle protein synthesis and catabolic systems after resistance training. Here, we measured changes in basal muscle protein synthesis, the ubiquitin-proteasome system, and autophagy-lysosome system-related factors after bouts of resistance exercise by intramuscular injection of MSCs. Mice performed three bouts of resistance exercise (each consisting of 50 maximal isometric contractions elicited by electrical stimulation) on the right gastrocnemius muscle every 48 h, and immediately after the first bout, mice were intramuscularly injected with either MSCs (2.0 × 106 cells) labeled with green fluorescence protein (GFP) or vehicle only placebo. Seventy-two hours after the third exercise bout, GFP was detected only in the muscle injected with MSCs with concomitant elevation of muscle protein synthesis. The injection of MSCs also increased protein ubiquitination. These results suggest that the intramuscular injection of MSCs augmented muscle protein turnover at the basal state after consecutive resistance exercise.

Simultaneous detection of the shuttling motion of liquid metal droplets in channels under alternating pressure and capacitive sensor signals

Implementing a signal-switching mechanism for the selective use of integrated sensors and actuators plays a crucial role in streamlining the functionality of miniaturized devices. Here, a liquid metal droplet (LMD)-based signal-switching mechanism is introduced to achieve such functionality. Pressure modulation with a 100-μm spatial resolution enabled precise control of the position of the LMDs within a channel. After integrating the channel with asymmetrically structured electrodes, the effect of the shuttle-like movement of LMD on the temporal changes in the overall capacitance was investigated. Consequently, analysis of the capacitive peaks revealed the directional movement of the LMDs, enabling estimation of the position of the LMDs without direct observation. In addition, we achieved successful signal extraction from the capacitive sensor that was linked to the activated electrodes, thereby enabling selective data retrieval. The proposed signal-switching mechanism method achieved a detection accuracy of ~0.1 pF. The sensor's ability to simultaneously detect the LMD position and generate a signal underscores its significant potential for multiplexing in multisensing systems, particularly in concealed environments, such as in vivo settings.

Dual-color live imaging unveils stepwise organization of multiple basal body arrays by cytoskeletons

For mucociliary clearance of pathogens, tracheal multiciliated epithelial cells (MCCs) organize coordinated beating of cilia, which originate from basal bodies (BBs) with basal feet (BFs) on one side. To clarify the self-organizing mechanism of coordinated intracellular BB-arrays composed of a well-ordered BB-alignment and unidirectional BB-orientation, determined by the direction of BB to BF, we generated double transgenic mice with GFP-centrin2-labeled BBs and mRuby3-Cep128-labeled BFs for long-term, high-resolution, dual-color live-cell imaging in primary-cultured tracheal MCCs. At early timepoints of MCC differentiation, BB-orientation and BB-local alignment antecedently coordinated in an apical microtubule-dependent manner. Later during MCC differentiation, fluctuations in BB-orientation were restricted, and locally aligned BB-arrays were further coordinated to align across the entire cell (BB-global alignment), mainly in an apical intermediate-sized filament-lattice-dependent manner. Thus, the high coordination of the BB-array was established for efficient mucociliary clearance as the primary defense against pathogen infection, identifying apical cytoskeletons as potential therapeutic targets.

Cooling-promoted myogenic differentiation of murine bone marrow mesenchymal stem cells through TRPM8 activation in vitro

TRPM8 agonist has been reported to promote osteogenic differentiation of mesenchymal stem cells (MSCs), therefore we evaluated whether cooling-induced activation of TRPM8 promotes myogenic differentiation of MSCs. We used 5-azacytidine as a myogenic differentiation inducer in murine bone marrow-derived MSCs. Addition of menthol, a TRPM8 agonist, to the differentiation induction medium significantly, increased the percentage of MyoD-positive cells, a specific marker of myogenic differentiation. We performed intracellular Ca2+ imaging experiments using fura-2 to confirm TRPM8 activation by cooling stimulation. The results confirmed that intracellular Ca2+ concentration ([Ca2+ ]i) increases due to TRPM8 activation, and TRPM8 antagonist inhibits increase in [Ca2+ ]i at medium temperatures below 19°C. We also examined the effect of cooling exposure time on myogenic differentiation of MSCs using an external cooling stimulus set at 17°C. The results showed that 60 min of cooling had an acceleratory effect on differentiation (2.18 ± 0.27 times). We observed that the TRPM8 antagonist counteracted the differentiation-promoting effect of the cooling. These results suggest that TRPM8 might modulate the multiple differentiation pathways of MSCs, and that cooling is an effective way of activating TRPM8, which regulates MSCs differentiation in vitro.

Transitional cell states sculpt tissue topology during lung regeneration

Organ regeneration requires dynamic cell interactions to reestablish cell numbers and tissue architecture. While we know the identity of progenitor cells that replace lost tissue, the transient states they give rise to and their role in repair remain elusive. Here, using multiple injury models, we find that alveolar fibroblasts acquire distinct states marked by Sfrp1 and Runx1 that influence tissue remodeling and reorganization. Unexpectedly, ablation of alveolar epithelial type-1 (AT1) cells alone is sufficient to induce tissue remodeling and transitional states. Integrated scRNA-seq followed by genetic interrogation reveals RUNX1 is a key driver of fibroblast states. Importantly, the ectopic induction or accumulation of epithelial transitional states induce rapid formation of transient alveolar fibroblasts, leading to organ-wide fibrosis. Conversely, the elimination of epithelial or fibroblast transitional states or RUNX1 loss, leads to tissue simplification resembling emphysema. This work uncovered a key role for transitional states in orchestrating tissue topologies during regeneration.

Efficient Adeno-associated Virus-mediated Transgenesis in Alveolar Stem Cells and Associated Niches

Targeted delivery of transgenes to tissue-resident stem cells and related niches offers avenues for interrogating pathways and editing endogenous alleles for therapeutic interventions. Here, we survey multiple adeno-associated virus (AAV) serotypes, administered via intranasal and retroorbital routes in mice, to target lung alveolar stem cell niches. We found that AAV5, AAV4, and AAV8 efficiently and preferentially transduce alveolar type-2 stem cells (AT2s), endothelial cells, and PDGFRA+ fibroblasts, respectively. Notably, some AAVs show different cell tropisms depending on the route of administration. Proof-of-concept experiments reveal the versatility of AAV5-mediated transgenesis for AT2-lineage labeling, clonal cell tracing after cell ablation, and conditional gene inactivation in both postnatal and adult mouse lungs in vivo. AAV6, but not AAV5, efficiently transduces both mouse and human AT2s in alveolar organoid cultures. Furthermore, AAV5 and AAV6 can be used to deliver guide RNAs and transgene cassettes for homologous recombination in vivo and ex vivo, respectively. Using this system coupled with clonal derivation of AT2 organoids, we demonstrate efficient and simultaneous editing of multiple loci, including targeted insertion of a payload cassette in AT2s. Taken together, our studies highlight the powerful utility of AAVs for interrogating alveolar stem cells and other specific cell types both in vivo and ex vivo.

Openable artificial intestinal tract device integrated with a permeable filter for evaluating drug permeation through cells

Organs-on-chips using cultured cells have been developed and applied for evaluating in vitro biological phenomena. We previously reported an openable artificial intestinal tract system, as an in vitro model of the small intestine, for in vitro drug screening. The intestinal tract device could be transformed using an integrated artificial muscle actuator. An initial flat state was suitable for cell culture, and the transformed tubular structure was used as a fluidic channel for perfusion tests. The previously developed intestinal tract system could be used to evaluate drug absorption by cells through perfusion testing. This study presents an improved artificial intestinal tract system for analysis of drug permeation, in addition to absorption. Permeable filters were integrated into the intestinal tract device. Integration of additional filters into the design of the existing artificial muscle actuator was accomplished by considering device performance and available filter locations. Filter permeability was evaluated by perfusion testing. MDCK-II cells were cultured on the device and visually and electrically evaluated. The openable device, equipped with new functions for further pharmacokinetic analysis, could perform and evaluate drug disposition using cultured cells. We anticipate that the improved, openable organ-on-a-chip device system will contribute to advances in in vitro drug screening technology.

Enhancement of solute diffusion in microdroplets using microrotors under rotational magnetic field

In vertical contact control (VCC), a microdroplet array selectively contacts with an opposite microdroplet array. Generally, VCC is useful for the dispenser mechanism based on solute diffusion between microdroplet pairs. However, sedimentation due to gravity can cause an inhomogeneous distribution of solutes in microdroplets. Therefore, it is necessary to enhance solute diffusion to achieve the accurate dispensing of a large quantity of solute in the direction opposite to that of gravity. Herein, we applied a rotational magnetic field to the microrotors in microdroplets to enhance the solute diffusion in microdroplets. Driven by microrotors, the rotational flow can generate a homogeneous distribution of solutes in microdroplets. We analyzed the diffusion dynamics of solutes using a phenomenological model, and the results showed that the rotation of microrotors can increase the diffusion constant of solutes.

Threshold magnetic field as a universal criterion for the selective transport of magnetized particles in microdroplets

Transportation of magnetized particles (MPs) against gravity is possible by applying a magnetic field to the particles. This transport phenomenon of MPs in microdroplets can be quantitatively assessed by determining the contribution of individual forces acting on the MPs. We studied the selective transportation of MPs in microdroplets. MPs in microdroplets were transported in the opposite direction to gravity when we applied an external magnetic field larger than a threshold value. We modulated the intensity of the external magnetic field and selectively manipulated the MPs. As a result, MPs were separated into different microdroplets based on their magnetic properties. Our quantitative investigation of transport dynamics shows that the threshold magnetic field depends only on the magnetic susceptibility and the density of MPs. This is a universal criterion for the selective transport of magnetized targets such as magnetized cells in microdroplets.

Design improvement of the conversion mechanism from balloon inflation to bending motion for inflatable film actuators

Various soft actuators have been investigated to overcome the drawbacks of conventional solid machines and explore the applications of soft robotics. In particular, and because they are expected to be applicable in minimally invasive medicine because of their safety, soft inflatable microactuators using an actuation conversion mechanism from balloon inflation to bending motion have been proposed for high-output bending motion. These microactuators could be applied to create an operation space by safely moving organs and tissues; however, the conversion efficiency could be further improved. This study aimed to improve conversion efficiency by investigating the design of the conversion mechanism. The contact conditions between the inflated balloon and conversion film were examined to improve the contact area for force transmission, with the contact area dependent on the length of the contact arc between the balloon and force conversion mechanism and on the amount of balloon deformation. In addition, surface contact friction between the balloon and film, which affects actuator performance, was also investigated. The generated force of the improved device is 1.21 N at 80 kPa when it bends 10 mm, which is 2.2 times the generated force of the previous design. This improved soft inflatable microactuator is expected to assist in performing operations in a limited space, such as in endoscopic or laparoscopic operations.

Multi-apical polarity of alveolar stem cells and their dynamics during lung development and regeneration

Epithelial cells of diverse tissues are characterized by the presence of a single apical domain. In the lung, electron microscopy studies have suggested that alveolar type-2 epithelial cells (AT2s) en face multiple alveolar sacs. However, apical and basolateral organization of the AT2s and their establishment during development and remodeling after injury repair remain unknown. Thick tissue imaging and electron microscopy revealed that a single AT2 can have multiple apical domains that enface multiple alveoli. AT2s gradually establish multi-apical domains post-natally, and they are maintained throughout life. Lineage tracing, live imaging, and selective cell ablation revealed that AT2s dynamically reorganize multi-apical domains during injury repair. Single-cell transcriptome signatures of residual AT2s revealed changes in cytoskeleton and cell migration. Significantly, cigarette smoke and oncogene activation lead to dysregulation of multi-apical domains. We propose that the multi-apical domains of AT2s enable them to be poised to support the regeneration of a large array of alveolar sacs.

Protein C activity as a potential prognostic factor for nursing home-acquired pneumonia

Introduction

Despite the poor prognosis for nursing home acquired pneumonia (NHAP), a useful prognostic factor is lacking. We evaluated protein C (PC) activity as a predictor of in-hospital death in patients with NHAP and community-acquired pneumonia (CAP).

Methods

This prospective, observational study included all patients hospitalized with pneumonia between July 2007 and December 2012 in a single hospital. We measured PC activity at admission and investigated whether it was different between survivors and non-survivors. We also examined whether PC activity < 55% was a predictor for in-hospital death of pneumonia by logistic regression analysis with CURB-65 items (confusion, blood urea >20 mg/dL, respiratory rate >30/min, and blood pressure <90/60 mmHg, age >65). When it was a useful prognostic factor for pneumonia, we combined PC activity with the existing prognostic scores, the pneumonia severity index (PSI) and CURB-65, and analyzed its additional effect by comparing the areas under the receiver operating characteristic curves (AUCs) of the modified and original scores.

Results

Participants comprised 75 NHAP and 315 CAP patients. PC activity was lower among non-survivors than among survivors in NHAP and all-pneumonia (CAP+NHAP). PC activity <55% was a useful prognostic predictor for NHAP (Odds ratio 7.39 (95% CI; 1.59–34.38), and when PSI or CURB-65 was combined with PC activity, the AUC improved (from 0.712 to 0.820 for PSI, and 0.657 to 0.734 for CURB-65).

Conclusions

PC activity was useful for predicting in-hospital death of pneumonia, especially in NHAP, and became more useful when combined with the PSI or CURB-65.

Active tactile sensing of small insect force by a soft microfinger toward microfinger-insect interactions

Human-robot interaction technology has contributed to improving sociality for humanoid robots. At scales far from human scales, a microrobot can interact with an environment in a small world. Microsensors have been applied to measurement of forces by flying or walking insects. Meanwhile, most previous works focused on the measurement of the behavior of insects. Here, we propose microrobot-insect interactions by soft microfingers integrated with artificial muscle actuators and tactile sensors, which has been developed for a haptic teleoperation robot system. A soft pneumatic balloon actuator acts as the artificial muscle, and a flexible strain sensor using a liquid metal provides tactile sensing. Force interaction between a pill bug and the microfinger could be accomplished. The microfinger (12 mm × 3 mm × 490 μm) can move and touch an insect, and it can detect reaction force from an insect. The measured reaction force from the legs of a pill bug as a representative insect was less than 10 mN. This paper presents a microfinger as an end effector for the active sensing of reaction force from a small insect. We anticipate that our results will lead to further evaluation of small living things as well as technology development for human-environment interaction.

Quality evaluation of cell spheroids for transplantation by monitoring oxygen consumption using an on-chip electrochemical device

Three-dimensional cell spheroids are superior cell-administration form for cell-based therapy which generally exhibit superior functionality and long-term survival after transplantation. Here, we nondestructively measured the oxygen consumption rate of cell spheroids using an on-chip electrochemical device (OECD) and examined whether this rate can be used as a marker to estimate the quality of cell spheroids. Cell spheroids containing NanoLuc luciferase-expressing mouse mesenchymal stem cell line C3H10T1/2 (C3H10T1/2/Nluc) were prepared. Spheroids of high or low quality were prepared by altering the medium change frequency. After transplantation into mice, the high-quality C3H10T1/2/Nluc spheroids exhibited a higher survival rate than the low-quality ones. The oxygen consumption rate of the high-quality C3H10T1/2/Nluc spheroids was maintained at high levels, whereas that of the low-quality spheroids decreased with time. These results indicate that OECD-based measurement of the oxygen consumption rate can be used to estimate the quality of cell spheroids without destructive analysis of the spheroids.

Temperature gradient sensing mechanism using liquid crystal droplets with 0.1-mK-level detection accuracy and high spatial resolution

We proposed the detection mechanism of the micro-levels of temperature gradient in a micro-electromechanical system using the unidirectional rotation of cholesteric-liquid crystal (Ch-LC) droplets. Ch-LC droplets in the presence of an isotropic phase subjected to a heat flux rotate with a speed proportional to the magnitude of the temperature gradient. We further quantified the temperature gradient-to-torque conversion efficiency to apply the thermomechanical cross-correlation to the detection of temperature gradient. Then, we observed the rotational behavior of Ch-LC droplets after introducing them onto model devices containing patterned Au thin-film electrodes. Direct electric current applied to these Au electrodes results in unidirectional rotation of the Ch-LC droplets in response to heat flux generated from the Au electrodes. By evaluating the possible temperature gradient detection resolution using Ch-LC droplet rotation, we show that Ch-LC droplets can achieve both high spatial resolution (~ 10 µm) and high detection accuracy (~ 0.1 mK/µm).

Mesenchymal Stem Cells Promote IL-6 Secretion and Suppress the Gene Expression of Proinflammatory Cytokines in Contractile C2C12 Myotubes

Sarcopenia is not only a major cause of disability but also a risk factor for obesity and diabetes in elderly persons. Exercise is an effective method for improving the sarcopenic condition by inducing the secretion of interleukin (IL)-6, which has the capacities to both promote muscle hypertrophy and regulate lipid metabolism and glucose homeostasis, by skeletal muscle. We previously showed that mesenchymal stem cells (MSCs) promote IL-6 secretion by lipopolysaccharide-stimulated C2C12 mouse skeletal muscle myotubes via paracrine mechanisms. Therefore, in this study, we investigated the effect of paracrine actions of MSCs on IL-6 and proinflammatory cytokine expression in contractile C2C12 myotubes by applying electrical stimulation. IL-6 secretion by C2C12 myotubes was increased by electrical stimulation, and a more significant increase in IL-6 secretion was observed in electrically stimulated C2C12 myotubes cultured in conditioned medium from MSCs. The activation of nuclear factor-κB in C2C12 myotubes was also promoted by the combination of conditioned medium from MSCs and electrical stimulation. Moreover, the increases in tumor necrosis factor-α and IL-1β mRNA expression in C2C12 myotubes induced by electrical stimulation were suppressed by culture in conditioned medium from MSCs. The present findings suggest that MSCs transplantation or injection of their extracellular vesicles improve the therapeutic effect of exercise against sarcopenia without exacerbating inflammation.

Defined conditions for long-term expansion of murine and human alveolar epithelial stem cells in three-dimensional cultures

Alveolar type 2 cells (AT2s) serve as stem cells of the alveoli and restore cell numbers after injury. Here, we describe a detailed protocol for the isolation, purification, and culture of murine and human AT2s. We have developed chemically defined and stroma-free culture conditions that enable expansion and maintenance of AT2s. The culture conditions are scalable and compatible with high-throughput chemical and genetic screenings and can potentially be used to generate large AT2 numbers for cell-based therapies. For complete details on the use and execution of this protocol, please refer to Katsura et al. (2020).

Investigation of Brain Function-Related Myokine Secretion by Using Contractile 3D-Engineered Muscle

Brain function-related myokines, such as lactate, irisin, and cathepsin B (CTSB), are upstream factors that control brain-derived neurotrophic factor (BDNF) expression and are secreted from skeletal muscle by exercise. However, whether irisin and CTSB are secreted by muscle contraction remains controversial. Three-dimensional (3D)-engineered muscle (3D-EM) may help determine whether skeletal muscle contraction leads to the secretion of irisin and CTSB, which has never been identified with the addition of drugs in conventional 2D muscle cell cultures. We aimed to investigate the effects of electrical pulse stimulation (EPS)-evoked muscle contraction on irisin and CTSB secretion in 3D-EM. The 3D-EM, which consisted of C2C12 myoblasts and type-1 collagen gel, was allowed to differentiate for 2 weeks and divided into the control and EPS groups. EPS was applied at 13 V, 66 Hz, and 2 msec for 3 h (on: 5 s/off: 5 s). Irisin and CTSB secretion into the culture medium was measured by Western blotting. Irisin secretion was significantly increased following EPS (p < 0.05). However, there was no significant difference in CTSB secretion between the two groups. The present study suggests that irisin may be a contractile muscle-derived myokine, but CTSB is not secreted by EPS-evoked muscle contractile stimulation in 3D-EM.

Liquid metal droplet shuttling in a microchannel toward a single line multiplexer with multiple sensors

Multiple sensors and actuators integrated in a small space, especially an elongated thin structure, require equivalent number of signal lines between microdevices, but there is limited space for signal wires. Thus, we propose a mechanism using a single microchannel where a liquid metal droplet moves and shuttles. A shuttling droplet switches multiple terminals of signal lines along a microchannel based on a traditional switching mechanism using a liquid metal droplet. Electrically conductive gallium alloy liquid metals (Galinstan) can flow in a microchannel due to their fluidity. The terminals consist of opposing electrode pairs in a microchannel. A change in a variable impedance connected to a terminal as a pseudo sensor can be read when a droplet flows in and connects electrode pairs. This paper presents switching and addressing objective terminals of chromium electrodes by a shuttling conductive droplet (500 µm in diameter and 10 mm long) in a microchannel (500 µm in diameter and 100 mm long). A demonstrated simple mechanism enables communication between multiple microdevices along a microchannel. We anticipate wide application of proposed mechanism toward a multiplexer, especially in microfluidic devices because of the advantages of utilizing microchannels as common microstructures for both microdevices and signal lines.

Development of Myeloperoxidase Anti-neutrophil Cytoplasmic Antibody-positive Necrotizing Crescentic Glomerulonephritis in an Elderly Patient with Immunological Kidney Disease

A 78-year-old man presented with hypercalcemia and renal disease with high serum IgG4 and positive myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA), exhibiting sarcoidosis-like chest findings. A renal biopsy revealed tubulointerstitial nephritis, membranous nephropathy (MN), and sub-capsular lymphoid aggregates without fulfilling the diagnostic criteria of IgG4-related disease or sarcoidosis. Steroid therapy ameliorated the serological and renal abnormalities. After 5 years, following gradual increases in the neutrophil count and upper respiratory infection (URI), necrotizing crescentic glomerulonephritis (NCGN) developed with an increased serum MPO-ANCA level. These results suggest that in the presence of MPO-ANCA in immune senescence, the persistent neutrophil increase with URI may lead to the development of NCGN.

Intramuscular injection of mesenchymal stem cells activates anabolic and catabolic systems in mouse skeletal muscle

Skeletal muscle mass is critical for good quality of life. Mesenchymal stem cells (MSCs) are multipotent stem cells distributed across various tissues. They are characterized by the capacity to secrete growth factors and differentiate into skeletal muscle cells. These capabilities suggest that MSCs might be beneficial for muscle growth. Nevertheless, little is known regarding the effects on muscle protein anabolic and catabolic systems of intramuscular injection of MSCs into skeletal muscle. Therefore, in the present study, we measured changes in mechanistic target of rapamycin complex 1 (mTORC1) signaling, the ubiquitin–proteasome system, and autophagy-lysosome system-related factors after a single intramuscular injection of MSCs with green fluorescence protein (GFP) into mouse muscles. The intramuscularly-injected MSCs were retained in the gastrocnemius muscle for 7 days after the injection, indicated by detection of GFP and expression of platelet-derived growth factor receptor-alpha. The injection of MSCs increased the expression of satellite cell-related genes, activated mTORC1 signaling and muscle protein synthesis, and increased protein ubiquitination and autophagosome formation (indicated by the expression of microtubule-associated protein 1 light chain 3-II). These results suggest that the intramuscular injection of MSCs activated muscle anabolic and catabolic systems and accelerated muscle protein turnover.

Calcium Peroxide-Containing Polydimethylsiloxane-Based Microwells for Inhibiting Cell Death in Spheroids through Improved Oxygen Supply

Multicellular spheroids are expected to be used for in vivo-like tissue models and cell transplantation. Microwell devices are useful for the fabrication of multicellular spheroids to improve productivity and regulate their size. However, the high cell density in microwell devices leads to accelerated cell death. In this study, we developed O₂-generating microwells by incorporating calcium peroxide (CaO₂) into polydimethylsiloxane (PDMS)-based microwells. The CaO₂-containing PDMS was shown to generate O₂ for 3 d. Then, CaO₂-containing PDMS was used to fabricate O₂-generating microwells using a micro-molding technique. When human hepatocellular carcinoma (HepG2) spheroids were prepared using the conventional microwells, the O₂ concentration in the culture medium reduced to approx. 67% of the cell-free level. In contrast, the O₂-generating microwells maintained O₂ at constant levels. The HepG2 spheroids prepared using the O₂-generating microwells had a larger number of live cells than those prepared using the conventional microwells. In addition, the O₂-generating microwells rescued hypoxia in the HepG2 spheroids and increased cell viability. Lastly, the O₂-generating microwells were also useful for the preparation of multicellular spheroids of other cell types (i.e., MIN6, B16-BL6, and adipose-derived stem cells) with high cell viability. These results showed that the O₂-generating microwells are useful for preparing multicellular spheroids with high cell viability.

Intravenous injection of mesenchymal stem cell spheroids improves the pulmonary delivery and prolongs in vivo survival

BACKGROUND

Because of the excellent therapeutic potential, mesenchymal stem cells (MSCs) have been used as cell therapeutics for various diseases. However, the survival rate and duration of MSCs after transplantation are extremely low and short, respectively. To solve these problems, in this study, we prepared multicellular spheroids of MSCs and investigated their survival and function after intravenous injection in mice.

METHODS AND RESULTS

The murine adipose-derived MSC line m17.ASC was cultured in agarose-based microwell plates to obtain size-controlled m17.ASC spheroids of an average diameter and cell number of approximately 170 μm and 1100 cells/spheroid, respectively. The intravenously injected m17.ASC spheroids mainly accumulated in the lung and showed a higher survival rate than suspended m17.ASC cells during the experimental period of 7 days. m17.ASC spheroids efficiently reduced the lipopolysaccharide-induced increase in plasma concentrations of interleukin-6 and tumor necrosis factor-α.

CONCLUSIONS

These results indicate that spheroid formation improved the pulmonary delivery and survival of MSCs, as well as their therapeutic potential against inflammatory pulmonary diseases.

Multicellular modeling of ciliopathy by combining iPS cells and microfluidic airway-on-a-chip technology

Mucociliary clearance is an essential lung function that facilitates the removal of inhaled pathogens and foreign matter unidirectionally from the airway tract and is innately achieved by coordinated ciliary beating of multiciliated cells. Should ciliary function become disturbed, mucus can accumulate in the airway causing subsequent obstruction and potentially recurrent pneumonia. However, it has been difficult to recapitulate unidirectional mucociliary flow using human-derived induced pluripotent stem cells (iPSCs) in vitro and the mechanism governing the flow has not yet been elucidated, hampering the proper humanized airway disease modeling. Here, we combine human iPSCs and airway-on-a-chip technology, to demonstrate the effectiveness of fluid shear stress (FSS) for regulating the global axis of multicellular planar cell polarity (PCP), as well as inducing ciliogenesis, thereby contributing to quantifiable unidirectional mucociliary flow. Furthermore, we applied the findings to disease modeling of primary ciliary dyskinesia (PCD), a genetic disease characterized by impaired mucociliary clearance. The application of an airway cell sheet derived from patient-derived iPSCs and their gene-edited counterparts, as well as genetic knockout iPSCs of PCD causative genes, made it possible to recapitulate the abnormal ciliary functions in organized PCP using the airway-on-a-chip. These findings suggest that the disease model of PCD developed here is a potential platform for making diagnoses and identifying therapeutic targets and that airway reconstruction therapy using mechanical stress to regulate PCP might have therapeutic value.

Risk factors associated with methicillin-resistant Staphylococcus aureus isolation from serially collected sputum samples of patients hospitalized with pneumonia

INTRODUCTION

Risk factors associated with the new detection of methicillin-resistant Staphylococcus aureus (MRSA) during hospitalization remain unclear. This study aimed to identify risk factors associated with MRSA isolation from the sputum of patients admitted with pneumonia, during their hospitalization.

METHODS

Patients were prospectively enrolled from 2003 to 2012. Sputum samples were collected for bacterial cultures on days 1, 4, 7, 11, and 14 of hospitalization and thereafter. Cases of MRSA first isolated from sputum obtained before day 4 were defined as "carriage on admission." Cases of MRSA first isolated on day 4 and thereafter, were defined as "new detection after admission." Statistical analysis was used to investigate the risk factors associated with MRSA isolation.

RESULTS

MRSA was isolated from 167 of 1,008 patients (carriage: 47; new detection: 120). Multivariate analysis revealed that the risk factors for MRSA carriage were activities of daily living (ADL) disability prior to admission (odds ratio [OR], 2.92; 95% confidence interval [CI], 1.37-6.22) and hospitalization within the previous 90 days (OR, 3.75; 95% CI, 1.90-7.41). ADL disability prior to admission (risk ratio [RR], 1.82; 95% CI, 1.17-2.84) and a high pneumonia severity index score upon admission (RR, 2.20; 95% CI, 1.37-3.65) were risk factors for new detection of MRSA.

CONCLUSIONS

Several risk factors were found to be associated with MRSA carriage and/or its new detection, based on the sputum samples from patients admitted with pneumonia. These factors may be indicators for selective surveillance and the early implementation of infection control measures.

Planar cell polarity induces local microtubule bundling for coordinated ciliary beating

Multiciliated cells (MCCs) in tracheas generate mucociliary clearance through coordinated ciliary beating. Apical microtubules (MTs) play a crucial role in this process by organizing the planar cell polarity (PCP)-dependent orientation of ciliary basal bodies (BBs), for which the underlying molecular basis remains elusive. Herein, we found that the deficiency of Daple, a dishevelled-associating protein, in tracheal MCCs impaired the planar polarized apical MTs without affecting the core PCP proteins, causing significant defects in the BB orientation at the cell level but not the tissue level. Using live-cell imaging and ultra-high voltage electron microscope tomography, we found that the apical MTs accumulated and were stabilized by side-by-side association with one side of the apical junctional complex, to which Daple was localized. In vitro binding and single-molecule imaging revealed that Daple directly bound to, bundled, and stabilized MTs through its dimerization. These features convey a PCP-related molecular basis for the polarization of apical MTs, which coordinate ciliary beating in tracheal MCCs.

Cell and tissue system capable of automated culture, stimulation, and monitor with the aim of feedback control of organs-on-a-chip

This paper presents progress in the automation of cell and tissue systems and attempts toward the in situ feedback control of organs-on-a-chip. Our study aims to achieve feedback control of a cell and tissue system by a personal computer (PC), whereas most studies on organs-on-a-chip focus on the automation of status monitoring. The implemented system is composed of subsystems including automated culture, stimulation, and monitoring. The monitoring function provides imaging as well as sampling and dispensing in combination with an external analyzer. Individual subsystems can be combined accordingly. First, monitoring of skeletal muscle (SM) and adipose tissues using this system was demonstrated. The highlight of this paper is the application of the system to the feedback control of the lipid droplet (LD) size, where biochemical stimulation using insulin and adrenaline is controlled by a PC according to the obtained LD imaging data. In this study, the system demonstrated its function of maintaining the desired size of LDs. Our results expand the possibility of PC-controllable cell and tissue systems by addressing the challenge of feedback control of organs-on-a-chip. The PC-controllable cell and tissue systems will contribute to living systems-on-a-chip based on homeostasis phenomena involving interactions between organs or tissues.

Incorporation of Gelatin Microspheres into HepG2 Human Hepatocyte Spheroids for Functional Improvement through Improved Oxygen Supply to Spheroid Core

The multicellular spheroid three-dimensional cell culture system can be used as a formulation for cell-based therapy. However, the viability and functions of the cells in the core region of the spheroid tend to decrease because of limited oxygen supply. In this study, we incorporated gelatin microspheres (GMS) into HepG2 human hepatocyte spheroids to allow oxygen to reach the spheroid core. GMS with an approximate diameter of 37 µm were fabricated by water-in-oil emulsification followed by freeze drying. GMS-containing HepG2 spheroids (GMS/HepG2 spheroids) were prepared by incubation of the cells with GMS at various mixing ratios in agarose gel-based microwells. Increasing the GMS ratio increased the diameter of the spheroids, and few spheroids formed with excess GMS. HepG2 cells in the GMS/HepG2 spheroids were more oxygenated than those in the GMS-free spheroids. GMS incorporation increased the viability of HepG2 cells in the spheroids and increased the CYP1A1 activity of the cells to metabolize 7-ethoxyresorufin, although mRNA expression of the CYP1A1 gene was hardly affected by GMS incorporation. These results indicate that incorporating GMS into HepG2 spheroids improves the hypoxic microenvironment in the spheroids and increases cell viability and CYP1A1 metabolic activity.

High-output bending motion of a soft inflatable microactuator with an actuation conversion mechanism

The improvement of soft inflatable microactuators using an actuation conversion mechanism is presented in terms of high-output generation; a bending inflatable microactuator with the conversion mechanism is designed to generate high-output bending motion. The designed microactuator consists of a pneumatic balloon on a base film and a conversion film over the balloon and ribs on the backside of the base film. A conversion film converts the inflating motion of a pneumatic balloon into a bending motion. The fabricated microactuator with a pneumatic balloon of 13 mm in diameter is 16 mm × 40 mm × 850 μm. A 25 μm thick polyimide film is used as a conversion film over the pneumatic balloon because polyimide film is both non-stretchable and flexible. An array of Si ribs (15 mm × 40 mm × 400 μm) is integrated on the backside of the base film. Analysis of the microactuators with and without the conversion mechanism indicates that the output performance is improved with the addition of the conversion mechanism, as designed. As a result, the microactuator with the conversion film generates a maximum force of 1.72 N at 80 kPa, whereas the microactuator without the conversion film generates a maximum force of 0.15 N at 40 kPa. The improved microactuator can provide 4.2 mN/mm³ as the force density. In addition to fundamental characterization, the performance characteristics of the actuators are examined by combining the fundamental results.

Comparison of ceftriaxone plus macrolide and ampicillin/sulbactam plus macrolide in treatment for patients with community-acquired pneumonia without risk factors for aspiration: an open-label, quasi-randomized, controlled trial

Background

Ceftriaxone (CTRX) and ampicillin/sulbactam (ABPC/SBT) are recommended by various guidelines as the first-line antibiotics for community-acquired pneumonia (CAP). However, which of these antibiotics is more effective for treating non-aspiration CAP remains unclear.

Methods

This study was a prospective, single-center, open-label, quasi-randomized controlled trial. Patients with adult CAP without risk for aspiration were allocated to either a CTRX or ABPC/SBT group based on the date of hospital admission. Macrolide was added to patients in each group. The primary outcome was the clinical response in the validated per-protocol (VPP) population at end of treatment (EOT). The secondary outcomes were clinical response during treatment and at end of study (EOS) in the VPP population, and mortality rate at day 30 in the modified intention-to-treat (MITT) population.

Results

Of 696 screened patients, 433 patients were excluded and 263 patients were allocated to receive either of the treatments. Males comprised 54% of patients and mean age and PSI were 62.1 ± 19.8 years and 69.3 ± 30.0, respectively, with 124 patients allocated to the CTRX group and 138 patients allocated to the ABPC/SBT group. The clinical effectiveness rate for the VPP population at EOT was 90% in the CTRX and 96% in the ABPC/SBT group (p = 0.072, 95% confidence interval [CI] of risk difference [RD]: − 12.6–0.8%). No significant difference in effectiveness at day 4 was observed between the CTRX and ABPC/SBT groups (p = 0.079, 95%CI of RD: − 12.1–0.4%), but at day 7, ABPC/SBT was significantly more effective than CTRX in the VPP population (p = 0.047, 95%CI of RD: − 13.3–-0.4%). No significant difference in late response at EOS was seen between CTRX and ABPC/SBT groups: cure (89 [86%] and 102 [94%]), relapse (5 [5%] and 1 [1%]) and failure (10 [10%] and 5 [5%]; p = 0.053). Deaths within 30 days in MITT population was higher in CTRX group (4 [3%]) than in ABPC/SBT group (0 [0%]) (p = 0.048, 95%CI of RD: 0.1–6.3%).

Conclusion

No significant difference in effectiveness was found between ABPC/SBT and CTRX at EOT. However, ABPC/SBT might be more effective in the early phase of treatment.

Trial registration

UMIN-CTR, UMIN000037464. Registered 25 July 2019 – Retrospectively registered, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000042262

Flexible Temperature Sensor Integrated with Soft Pneumatic Microactuators for Functional Microfingers

The integration of a flexible temperature sensor with a soft microactuator (a pneumatic balloon actuator) for a functional microfinger is presented herein. A sensor integrated with a microactuator can actively approach a target for contact detection when a distance exists from the target or when the target moves. This paper presents a microfinger with temperature sensing functionality. Moreover, thermocouples, which detect temperature based on the Seebeck effect, are designed for use as flexible temperature sensors. Thermocouples are formed by a pair of dissimilar metals or alloys, such as copper and constantan. Thin-film metals or alloys are patterned and integrated in the microfinger. Two typical thermocouples (K-type and T-type) are designed in this study. A 2.0 mm × 2.0 mm sensing area is designed on the microfinger (3.0 mm × 12 mm × 400 μm). Characterization indicates that the output voltage of the sensor is proportional to temperature, as designed. It is important to guarantee the performance of the sensor against actuation effects. Therefore, in addition to the fundamental characterization of the temperature sensors, the effect of bending deformation on the characteristics of the temperature sensors is examined with a repeated bending test consisting of 1000 cycles.