Ultrasound microbubble technology plays a significant role in stem cell therapy for cardiovascular diseases. This technology demonstrates unique advantages in stem cell tracking，regulating the stem cell growth environment，and achieving precise gene delivery. These advantages not only help improve the survival rate and functionality of stem cells，reduce cell death，but also effectively promote stem cell proliferation and differentiation，while enhancing gene transfection efficiency. This article will provide an in-depth review of the application prospects of ultrasound microbubble technology in the field of stem cell therapy for cardiovascular diseases.

Objective:To prepare novel targeted lipid nanobubbles（MEB-NBs）that can be loaded with exosomes（Exo），and test the property and explore the specific invitro target-seeking ability of MEB-NBs. Methods:The core lipid nanobubbles（NBs）were prepared using mechanical oscillation methods，and Exo was connected to the NBs through membrane fusion. The target antibody MYH6 was linked to the NBs using a phospholipid coupling covalent method，resulting in the preparation of targeted lipid nanobubbles MEB-NBs loaded with Exo. The morphology，particle size，and surface potential of the prepared lipid nanobubbles MEB-NBs were observed，and the co-loading of Exo and NBs was verified using laser confocal and fluorescence resonance energy transfer techniques. The in vitro imaging capability and biosafety of MEB-NBs were evaluated，and the loading rate and drug content of Exo carried by MEB-NBs were measured. The ability of MEB-NBs to specifically target hiPSC-CMs cells was observed using flow cytometry，small animal in vivo imaging systems，and laser confocal microscopy. Results:The average particle size of the prepared MEB-NBs was（597.10 ± 47.70）nm，the surface potential was（-11.70 ± 0.21）mV，and the concentration was（2.43 ± 0.06）×10 7/ml. Laser confocal microscopy and FRET results confirmed that the Exo was effectively connected with the NBs；When the Exo concentration was 250 μg/ml，the Exo loading rate and drug loading of MEB-NBs were both 73.8%，and the results of laser confocal microscopy showed that MEB-NBs could be effectively targeted to hiPSC-CMs cells. MEB-NBs were well developed in vitro and had good biological safety. Conclusions:This study constructs novel Exo-loaded targeted lipid nanobubbles（MEB-NBs）that demonstrate stable physicochemical properties and ultrasound imaging capabilities. The developed MEB-NBs precisely target hiPSC-CMs cells，providing an innovative drug delivery system with enhanced therapeutic efficacy for Exo-based therapies.

Purpose To construct an ultrasound molecular probe carrying miRNA-452/Let-7i and analyze its targeting effect on human induced pluripotent stem cell derived cardiomyocytes(hiPSCs-CMs)in vitro.Materials and Methods The biotinylated core lipid microbubbles(NBs),lipid microbubbles carrying adenovirus overexpressing miRNA-452/Let-7i(Ad-miR-452/Let-7i)and ultrasound molecular probes carrying adenovirus overexpressing miRNA-452/Let-7i and targeting protein MYH6(Ad-miR-452/Let7i-MYH6)were synthesized,and the expression rates of fluorescent proteins to verify their binding were compared.The physical and chemical properties,stability,and in vitro imaging of those abovementioned parameters were measured,respectively,and theirs biological safety was evaluated.hiPSCs-CMs was divided into Ad-miR-452/Let-7i group and Ad-miR-452/Let7i-MYH6 group,then theirs cell binding status were compared.Results The constructed NBs,Ad-miR-452/Let-7i and Ad-miR-452/Let7i-MYH6 had regular morphology and good stability.Detection data showed that theirs concentrations were(1.62±0.40)×108 particles/ml,(1.83±0.20)×108 particles/ml and(1.35±0.33)×108 particles/ml,respectively.The average particle sizes were(605.94±17.46)nm,(726.53±14.95)nm and(729.31±16.62)nm,respectively.The zeta potentials were(2.61±0.30)mV,(-11.21±0.71)mV and(-12.28±0.52)mV,respectively.The polydispersity indices were 0.24±0.07,0.26±0.14 and 0.25±0.13,respectively.With a concentration of 107 particles/ml,the imaging strengths of the three samples were 99.24±5.04,102.18±3.61 and 99.07±3.87,respectively.The miRNA-loaded ultrasound molecular probes exhibited no significant toxicity to the cells,with in vitro imaging lasting over 15 minutes,and they could specifically bind to hiPSC-CMs.Conclusion The constructed ultrasound molecular probe has stability and in vitro targeting,effectively improving virus transfection efficiency.

Hemodynamic alterations of left heart valvar diseases may induce varying degrees of myocardial structural and functional remodeling.Two-dimensional speckle-tracking echocardiography can noninvasively assess myocardial strain and strain rate as well as detect subclinical systolic dysfunction,hence providing significant incremental value for evaluating global strain,layer-specific strain and segmental variations in strain among patients with left heart valvar diseases,also for guiding clinical management and improving prognosis.The advances of speckle-tracking echocardiography for assessing myocardial strain in left heart valvar diseases were reviewed in this article.

Purpose To construct an ultrasound molecular probe carrying miRNA-452/Let-7i and analyze its targeting effect on human induced pluripotent stem cell derived cardiomyocytes(hiPSCs-CMs)in vitro.Materials and Methods The biotinylated core lipid microbubbles(NBs),lipid microbubbles carrying adenovirus overexpressing miRNA-452/Let-7i(Ad-miR-452/Let-7i)and ultrasound molecular probes carrying adenovirus overexpressing miRNA-452/Let-7i and targeting protein MYH6(Ad-miR-452/Let7i-MYH6)were synthesized,and the expression rates of fluorescent proteins to verify their binding were compared.The physical and chemical properties,stability,and in vitro imaging of those abovementioned parameters were measured,respectively,and theirs biological safety was evaluated.hiPSCs-CMs was divided into Ad-miR-452/Let-7i group and Ad-miR-452/Let7i-MYH6 group,then theirs cell binding status were compared.Results The constructed NBs,Ad-miR-452/Let-7i and Ad-miR-452/Let7i-MYH6 had regular morphology and good stability.Detection data showed that theirs concentrations were(1.62±0.40)×108 particles/ml,(1.83±0.20)×108 particles/ml and(1.35±0.33)×108 particles/ml,respectively.The average particle sizes were(605.94±17.46)nm,(726.53±14.95)nm and(729.31±16.62)nm,respectively.The zeta potentials were(2.61±0.30)mV,(-11.21±0.71)mV and(-12.28±0.52)mV,respectively.The polydispersity indices were 0.24±0.07,0.26±0.14 and 0.25±0.13,respectively.With a concentration of 107 particles/ml,the imaging strengths of the three samples were 99.24±5.04,102.18±3.61 and 99.07±3.87,respectively.The miRNA-loaded ultrasound molecular probes exhibited no significant toxicity to the cells,with in vitro imaging lasting over 15 minutes,and they could specifically bind to hiPSC-CMs.Conclusion The constructed ultrasound molecular probe has stability and in vitro targeting,effectively improving virus transfection efficiency.

Hemodynamic alterations of left heart valvar diseases may induce varying degrees of myocardial structural and functional remodeling.Two-dimensional speckle-tracking echocardiography can noninvasively assess myocardial strain and strain rate as well as detect subclinical systolic dysfunction,hence providing significant incremental value for evaluating global strain,layer-specific strain and segmental variations in strain among patients with left heart valvar diseases,also for guiding clinical management and improving prognosis.The advances of speckle-tracking echocardiography for assessing myocardial strain in left heart valvar diseases were reviewed in this article.

Ultrasound microbubble technology plays a significant role in stem cell therapy for cardiovascular diseases. This technology demonstrates unique advantages in stem cell tracking，regulating the stem cell growth environment，and achieving precise gene delivery. These advantages not only help improve the survival rate and functionality of stem cells，reduce cell death，but also effectively promote stem cell proliferation and differentiation，while enhancing gene transfection efficiency. This article will provide an in-depth review of the application prospects of ultrasound microbubble technology in the field of stem cell therapy for cardiovascular diseases.

Objective:To prepare novel targeted lipid nanobubbles（MEB-NBs）that can be loaded with exosomes（Exo），and test the property and explore the specific invitro target-seeking ability of MEB-NBs. Methods:The core lipid nanobubbles（NBs）were prepared using mechanical oscillation methods，and Exo was connected to the NBs through membrane fusion. The target antibody MYH6 was linked to the NBs using a phospholipid coupling covalent method，resulting in the preparation of targeted lipid nanobubbles MEB-NBs loaded with Exo. The morphology，particle size，and surface potential of the prepared lipid nanobubbles MEB-NBs were observed，and the co-loading of Exo and NBs was verified using laser confocal and fluorescence resonance energy transfer techniques. The in vitro imaging capability and biosafety of MEB-NBs were evaluated，and the loading rate and drug content of Exo carried by MEB-NBs were measured. The ability of MEB-NBs to specifically target hiPSC-CMs cells was observed using flow cytometry，small animal in vivo imaging systems，and laser confocal microscopy. Results:The average particle size of the prepared MEB-NBs was（597.10 ± 47.70）nm，the surface potential was（-11.70 ± 0.21）mV，and the concentration was（2.43 ± 0.06）×10 7/ml. Laser confocal microscopy and FRET results confirmed that the Exo was effectively connected with the NBs；When the Exo concentration was 250 μg/ml，the Exo loading rate and drug loading of MEB-NBs were both 73.8%，and the results of laser confocal microscopy showed that MEB-NBs could be effectively targeted to hiPSC-CMs cells. MEB-NBs were well developed in vitro and had good biological safety. Conclusions:This study constructs novel Exo-loaded targeted lipid nanobubbles（MEB-NBs）that demonstrate stable physicochemical properties and ultrasound imaging capabilities. The developed MEB-NBs precisely target hiPSC-CMs cells，providing an innovative drug delivery system with enhanced therapeutic efficacy for Exo-based therapies.

Objective:To prepare dual-targeted lipid ultrasound microbubbles loaded with ANM33 (HA-PANBs) and evaluate its feasibility in targeting foam cells by stages and achieving precise intracellular drug release in vitro. Methods:The dual-targeteded lipid ultrasound microbubbles were designed with nanobubbles (NBs) as the microbubble core, hyaluronic acid (HA) as the first-stage targeting ligand for damaged endothelial cells, aptamer PM1 as the second-stage targeting moiety for foam cells, and ANM33 as the therapeutic factor. Simultaneously with the characterization of the lipid bubbles, the stability and in vitro contrast-enhanced ultrasound imaging capability were detected. Then a co-culture model of damaged human umbilical vein endothelial cells (HUVEC) and macrophages (RAW264.7, MΦ) was established, combined with flow cytometry, oil red O staining and small animal in vivo imaging to evaluate the ability of HA-PANBs in targeting foam cells precisely and releasing ANM33. Results:The HA-PANBs exhibited regular morphology and good structural stability, with a particle size of (1 357.53±140.20)nm and a surface potential of (-5.61±0.73)mV. HA, PM1 and ANM33 were effectively connected. In the damaged HUVEC/MΦ co-culture system, the HA-PANBs group demonstrated the best targeting effect on foam cells, with an effective uptake of (80.65±2.12)%, which was 56.74% higher than that of the NBs group. Oil red O staining revealed that the cholesterol efflux capacity of foam cells in the HA-PANBs group was significantly better than that in the NBs group, the results were statistically different [(629.80±21.99) a.u.vs (1 071.00±55.49)a.u., P<0.05]. Conclusions:The dual-targeted lipid ultrasound microbubbles (HA-PANBs) can precisely target foam cells and significantly enhance their cholesterol efflux, providing a new strategy for the early non-invasive diagnosis and treatment of atherosclerosis.

Background::Carotid intima-media thickness (IMT) and diameter, stiffness, and wave reflections, are independent and important clinical biomarkers and risk predictors for cardiovascular diseases. The purpose of the present study was to establish nationwide reference values of carotid properties for healthy Chinese adults and to explore potential clinical determinants.Methods::A total of 3053 healthy Han Chinese adults (1922 women) aged 18-79 years were enrolled at 28 collaborating tertiary centers throughout China between April 2021 and July 2022. The real-time tracking of common carotid artery walls was achieved by the radio frequency (RF) ultrasound system. The IMT, diameter, compliance coefficient, β stiffness, local pulse wave velocity (PWV), local systolic blood pressure, augmented pressure (AP), and augmentation index (AIx) were then automatically measured and reported. Data were stratified by age groups and sex. The relationships between age and carotid property parameters were analyzed by Jonckheere-Terpstra test and simple linear regressions. The major clinical determinants of carotid properties were identified by Pearson’s correlation, multiple linear regression, and analyses of covariance.Results::All the parameters of carotid properties demonstrated significantly age-related trajectories. Women showed thinner IMT, smaller carotid diameter, larger AP, and AIx than men. The β stiffness and PWV were significantly higher in men than women before forties, but the differences reversed after that. The increase rate of carotid IMT (5.5 &mu;m/year in women and 5.8 &mu;m/year in men) and diameter (0.03 mm/year in both men and women) were similar between men and women. For the stiffness and wave reflections, women showed significantly larger age-related variations than men as demonstrated by steeper regression slopes (all P for age by sex interaction <0.05). The blood pressures, body mass index (BMI), and triglyceride levels were identified as major clinical determinants of carotid properties with adjustment of age and sex. Conclusions::The age- and sex-specific reference values of carotid properties measured by RF ultrasound for healthy Chinese adults were established. The blood pressures, BMI, and triglyceride levels should be considered for clinical application of corresponding reference values.