Effect of Ultrasound on Thrombus debris during Sonothrombolysis in a Microfluidic device.

Microbubble-mediated sonothrombolysis has been proven to be a non-invasive and efficient method for thrombolysis. Nevertheless, there is a potential risk that the thrombus debris generated during the dissolution of the original thrombus are too large and can lead to hazardous emboli. Using a sonothrombolysis microfluidic platform, we investigated the effects of ultrasound power, thrombolytic agent and microbubble concentration on the size of thrombus debris with the example of microbubble-mediated sonothrombolysis of arterial thrombus. Additionally, we studied the effects of ultrasound power on the size and shape of thrombus debris produced by acute and chronic arterial sonothrombolysis. In acute arterial sonothrombolysis, ultrasound power has significant effect on the size of thrombus debris and steadily increases with the increase of ultrasound power. Conversely, in chronic arterial sonothrombolysis, the size of thrombus debris is minimally affected by ultrasound power. Using the sonothrombolysis microfluidic platform, the relationship between ultrasound power and the safety of sonothrombolysis has been illustrated, and the sonothrombolysis microfluidic platform is demonstrated to be a promising tool for further studies on the process of sonothrombolysis.

Interventional Removal of Travelling Microthrombi Using Targeted Magnetic Microbubble.

Microthrombus is one of the major causes of the sequelae of Corona Virus Disease 2019 (COVID-19 and leads to subsequent embolism and necrosis. Due to their small size and irregular movements, the early detection and efficient removal of microthrombi in vivo remain a great challenge. In this work, an interventional method is developed to identify and remove the traveling microthrombi using targeted-magnetic-microbubbles (TMMBs) and an interventional magnetic catheter. The thrombus-targeted drugs are coated on the TMMBs and magnetic nanoparticles are shelled inside, which allow not only targeted adhesion onto the traveling microthrombi, but also the effective capture by the magnetic catheter in the vessel. In the proof-of-concept experiments in the rat models, the concentration of microthrombus is reduced by more than 60% in 3 min, without damaging the organs. It is a promising method for treating microthrombus issues.

Dual-Frequency Ultrasound Assisted Thrombolysis in Interventional Therapy of Deep Vein Thrombosis.

Deep vein thrombosis (DVT) is one of the main causes of disability and death worldwide. Currently, the treatment of DVT still needs a long time and faces a high risk of major bleeding. It is necessary to find a rapid and safe method for the therapy of DVT. Here, a dual-frequency ultrasound assisted thrombolysis (DF-UAT) is reported for the interventional treatment of DVT. A series of piezoelectric elements are placed in an interventional catheter to emit ultrasound waves with two independent frequencies in turn. The low-frequency ultrasound drives the drug-loaded droplets into the thrombus, while the high-frequency ultrasound causes the cavitation of the droplets in the thrombus. With the joint effect of the enhanced drug diffusion and the cavitation under the dual-frequency ultrasound, the thrombolytic efficacy can be improved. In a proof-of-concept experiment performed with living sheep, the recanalization of the iliac vein is realized in 15 min using the DF-UAT technology. Therefore, the DF-UAT can be one of the most promising methods in the interventional treatment of DVT.

The exact phenomenon and early signaling events of the endothelial cytoskeleton response to ultrasound.

Low-intensity ultrasound can be applied for medical imaging and disease treatment in clinical and experimental studies. However, the biological effects of ultrasound on blood vessels, especially endothelial cells (ECs) are still unclear. In this study, the laws of endothelial cytoskeleton changes under ultrasound induction are investigated. ECs are exposed to low-intensity ultrasound, and the cytoskeletal morphology is analyzed by a filamentous (F)-actin staining technique. We further analyze the characteristics of cytoskeleton rupture using indirect immunofluorescence techniques and cytoskeleton electron microscopy. Finally, the biological effects induced by ultrasound at the tissue level are investigated in an ex vivo blood-vessel model. Significant changes in cytoskeletal structure are detected when induced by ultrasound, including cytoskeletal rupture, blebbing and apoptosis. Moreover, a temporal threshold of ECs injury under different ultrasonic intensities is established. This study illustrates a pattern of significant changes in the cytoskeletal structure of ECs induced by ultrasound. The finding serves as a guide for selecting a safe threshold for clinical ultrasound applications.

Cysteine Pathogenic Variants of PMM2 Are Sensitive to Environmental Stress with Loss of Structural Stability.

Congenital disorders of glycosylation (CDG) are severe metabolic disorders caused by an imbalance in the glycosylation pathway. Phosphomannomutase2 (PMM2-CDG), the most prevalent CDG, is mainly due to the disorder of PMM2. Pathogenic variants in cysteine have been found in various diseases, and cysteine residues have a potential as therapeutic targets. PMM2 harbor six cysteines; the variants Cys9Tyr (C9Y) and Cys241Ser (C241S) of PMM2 have been identified to associate with CDG, but the underlying molecular mechanisms remain uncharacterized. Here, we purified PMM2 wild type (WT), C9Y, and C241S to investigate their structural characteristics and biophysical properties by spectroscopic experiments under physiological temperature and environmental stress. Notably, the variants led to drastic changes in the protein properties and were prone to aggregate at physiological temperature. Meanwhile, PMM2 was sensitive to oxidative stress, and the cysteine pathogenic variants led to obvious aggregate formation and a higher cellular apoptosis ratio under oxidative stress. Molecular dynamic simulations indicated that the pathogenic variants changed the core domain of homomeric PMM2 and subunit binding free energy. Moreover, we tested the potential drug targeting PMM2-celastrol in cell level and explained the result by molecular docking simulation. In this study, we delineated the pathological mechanism of the cysteine substitution in PMM2, which addressed the vital role of cysteine in PMM2 and provided novel insights into prevention and treatment strategies for PMM2-CDG.

Nanodroplet-Coated Microbubbles Used in Sonothrombolysis with Two-Step Cavitation Strategy.

Thrombosis is a major cause of morbidity and mortality and sonothrombolysis is a promising method for its treatment. However, the slow diffusion of the thrombolytic agents into the thrombus results in slow recanalization. Here, nanodroplet-coated microbubbles (NCMBs) are designed and fabricated and a two-step cavitation strategy is used to accelerate the thrombolysis. The first cavitation of the NCMBs, cavitation and collapse of the microbubbles induced by low frequency ultrasound, drives the nanodroplets on the shell into the thrombus, while the second cavitation, the phase-change and volume expansion of drug-loaded nanodroplets triggered by high frequency ultrasound, loosens the thrombus by the sono-porosity effect. This two-step cavitation of the NCMBs is verified using a fibrin agarose model, where a rapid diffusion of the thrombolytic agents is observed. Furthermore, the NCMBs reach much higher thrombolysis efficiency in both in vitro and proof-of-concept experiments performed with living mice. The nanodroplet-coated microbubbles are a promising diffusion medicines carrier for efficient drug delivery.

Fatigue of red blood cells under periodic squeezes in ECMO.

Hemolysis usually happens instantly when red blood cells (RBCs) rupture under a high shear stress. However, it is also found to happen gradually in the extracorporeal membrane oxygenation (ECMO) under low but periodic squeezes. In particular, the gradual hemolysis is accompanied by a progressive change in morphology of RBCs. In this work, the gradual hemolysis is studied in a microfluidic device with arrays of narrow gaps the same as the constructions in ECMO. RBCs are seen to deform periodically when they flow through the narrow gaps, which causes the release of adenosine-triphosphate (ATP) from RBCs. The reduced ATP level in the cells leads to the fatigue of RBCs with the progressive changes in morphology and the gradual loss of deformability. An empirical model for the fatigue of RBCs is established under the periodic squeezes with controlled deformation, and it reveals a different way of the hemolysis that is dominated by the squeeze frequency. This finding brings a new insight into the mechanism of hemolysis, and it helps to improve the design of circulatory support devices.

Enhanced thrombolysis by endovascular low-frequency ultrasound with bifunctional microbubbles in venous thrombosis: in vitro and in vivo study.

There is a need to improve the efficacy and safety of endovascular techniques in venous thrombotic diseases, and microbubble enhanced sonothrombolysis is a promising approach. However, whether endovascular low-frequency ultrasound (LFUS) can be utilized in microbubble enhanced sonothrombolysis is unclear. Here, we present a catheter-based thrombolytic system that combines unfocused low-frequency low-intensity ultrasound with novel fibrin-targeted drug-loaded bifunctional microbubbles. We develop an in vitro flow model and an in vivo rabbit inferior vena cava (IVC) thrombosis model to evaluate the safety and efficacy of the thrombolytic system. The results indicate that microbubble enhanced sonothrombolysis with endovascular LFUS treatment for 30 min is equally effective compared to pure pharmacologic treatment. Furthermore, the thrombolytic efficacy of this system is safely and substantially improved by the introduction of a fibrin-targeted drug-loaded bifunctional microbubble with a reduction of the fibrinolytic agent dosage by 60%. The microbubble enhanced endovascular LFUS sonothrombolysis system with excellent thrombolytic efficacy may serve as a new therapeutic approach for venous thrombotic diseases.

Interventional Microbubble Enhanced Sonothrombolysis on Left Ventricular Assist Devices.

The left ventricular assist device (LVAD) is often used in the treatment of heart failure. However, 4% to 9% implanted LVAD will have thrombosis problem in one year, which is fatal to the patient's life. In this work, an interventional sonothrombolysis (IST) method is developed to realize the thrombolysis on LVAD. A pair of ultrasound transducer rings is installed on the shell of LVAD, and drug-loaded microbubbles are injected into the LVAD through the interventional method. The microbubbles are adhere on the thrombus with the coated thrombus-targeted drugs, and the thrombolytic drugs carried by the bubbles are brought into the thrombus by the cavitation of bubbles under the ultrasound. In a proof-of-concept experiment in a live sheep model, the thrombus on LVAD is dissolved in 30 min, without damages on LVADs and organs. This IST exhibits to be more efficient and safer compared with other thrombolysis methods on LVAD.

Role of glucose in the repair of cell membrane damage during squeeze distortion of erythrocytes in microfluidic capillaries.

The rapid development of portable precision detection methods and the crisis of insufficient blood supply worldwide has led scientists to study mechanical visualization features beyond the biochemical properties of erythrocytes. Combined evaluation of currently known biochemical biomarkers and mechanical morphological biomarkers will become the mainstream of single-cell detection in the future. To explore the mechanical morphology of erythrocytes, a microfluidic capillary system was constructed in vitro, with flow velocity and glucose concentration as the main variables, and the morphology and ability of erythrocytes to recover from deformation as the main objects of analysis. We showed the mechanical distortion of erythrocytes under various experimental conditions. Our results showed that glucose plays important roles in improving the ability of erythrocytes to recover from deformation and in repairing the damage caused to the cell membrane during the repeated squeeze process. These protective effects were also confirmed in in vivo experiments. Our results provide visual detection markers for single-cell chips and may be useful for future studies in cell aging.

Arsenicitalea aurantiaca gen. nov., sp. nov., a new member of the family Hyphomicrobiaceae, isolated from high-arsenic sediment.

A novel arsenic-resistant bacterium, designated 42-50T, was isolated from the high-arsenic sediment of Jianghan Plain, Hubei Province, China. Phylogenetic and biochemical analysis indicated that this bacterium represents the first species of a novel genus belonging to the family Hyphomicrobiaceae. The 16S rRNA gene of strain 42-50T shares 96.3-94.2, 96.3, 96.2 and 94.9-93.8 % sequence identities to those of species from the genera Devosia, Youhaiella, Paradevosia and Pelagibacterium, respectively. The major cellular fatty acids are C16 : 0, C18 : 0, C18 : 1ω7c 11-methyl and summed feature 8 (comprising C18 : 1ω7c and C18 : 1ω6c). The predominant polar lipids are diphosphatidylglycerol, phosphatidylglycerol and two unidentified glycolipids. The predominant respiratory quinone is ubiquinone-10 (Q-10). The DNA G+C content of strain 42-50T is 73.7 mol%. The distinct phylogenetic lineage and unique cellular fatty acids suggest that strain 42-50T represents a novel species of a new genus affiliated with the family Hyphomicrobiaceae, for which the name Arsenicitalea aurantiaca gen. nov., sp. nov. is proposed. The type strain is 42-50T (=CCTCC AB 2014325T=KCTC 42825T).

Luteimonas arsenica sp. nov., an arsenic-tolerant bacterium isolated from arsenic-contaminated soil.

A Gram-stain-negative, rod-shaped bacterium that formed yellow and viscous colonies was isolated from arsenic-contaminated soil of the Jianghan plain, Hubei Province, China, and it was designated 26-35T. This strain was capable of resisting arsenate and arsenite with MICs of 40 and 20 mM, respectively. The 16S rRNA gene of the novel isolate displayed 96.7-94.2 % sequence similarities to those of other known species of the genus Luteimonas. The respiratory quinone was ubiquinone-8 (Q-8). The DNA G+C content was 71.4 mol%. The predominant cellular fatty acids were iso-C15 : 0, iso-C16 : 0, iso-C17 : 0, iso-C11 : 0, iso-C11 : 0 3-OH and iso-C17 : 1ω9c. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic and physiological analysis indicated that the isolate represents a novel species of the genus Luteimonas, for which the name Luteimonas arsenica sp. nov. is proposed. The type strain is 26-35T (=KCTC 42824T=CCTCC AB 2014326T).

Isolation and characterization of a radiation-resistant bacterium from Taklamakan Desert showing potent ability to accumulate Lead (II) and considerable potential for bioremediation of radioactive wastes.

Radioactive wastes always contain radioactive substances and a lot of Pb compound and other heavy metals, which severely contaminate soils and groundwater. Thus, search for radiation-resistant microorganisms that are capable of sequestering Pb contaminants from the contaminated sites is urgently needed. However, very few such microorganisms have been found so far. In the present study, we discovered a novel Gram-negative bacterium from the arid Taklamakan desert, which can strongly resist both radiation and Pb(2+). Phylogenetic and phenotypic analysis indicated that this bacterial strain is closely affiliated with Microvirga aerilata, and was thus referred to as Microvirga aerilata LM (=CCTCC AB 208311). We found that M. aerilata LM can effectively accumulate Pb and form intracellular precipitations. It also keeps similar ability to remove Pb(2+) under radioactive stress. Our data suggest that M. aerilata LM may offer an effective and eco-friendly in situ approach to remove soluble Pb contaminants from radioactive wastes.

Pontibacter diazotrophicus sp. nov., a novel nitrogen-fixing bacterium of the family Cytophagaceae.

Few diazotrophs have been found to belong to the family Cytophagaceae so far. In the present study, a Gram-negative, rod-shaped bacterium that forms red colonies, was isolated from sands of the Takalamakan desert. It was designated H4XT. Phylogenetic and biochemical analysis indicated that the isolate is a new species of the genus Pontibacter. The 16S rRNA gene of H4XT displays 94.2-96.8% sequence similarities to those of other strains in Pontibacter. The major respiratory quinone is menaquinone-7 (MK-7). The DNA G+C content is 46.6 mol%. The major cellular fatty acids are iso-C15∶0, C16∶1ω5c, summed feature 3 (containing C16∶1ω6c and/or C16∶1ω7c) and summed feature 4 (comprising anteiso-C17∶1B and/or iso-C17∶1I). The major polar lipids are phosphatidylethanolamine (PE), one aminophospholipid (APL) and some unknown phospholipids (PLs). It is interesting to see that this bacterium can grow very well in a nitrogen-free medium. PCR amplification suggested that the bacterium possesses at least one type of nitrogenase gene. Acetylene reduction assay showed that H4XT actually possesses nitrogen-fixing activity. Therefore, it can be concluded that H4XT is a new diazotroph. We thus referred it to as Pontibacter diazotrophicus sp. nov. The type strain is H4XT ( = CCTCC AB 2013049T = NRRL B-59974T).