Progress of Piezoelectric Semiconductor Nanomaterials in Sonodynamic Cancer Therapy.

Sonodynamic therapy is an emerging noninvasive tumor treatment method that utilizes ultrasound to stimulate sonosensitizers to produce a large amount of reactive oxygen species, inducing tumor cell death. Though sonodynamic therapy has very promising prospects in cancer treatment, the application of early organic sonosensitizers has been limited in efficacy due to the high blood clearance-rate, poor water solubility, and low stability. Inorganic sonosensitizers have thus been developed, among which piezoelectric semiconductor materials have received increasing attention in sonodynamic therapy due to their piezoelectric properties and strong stability. In this review, we summarized the designs, principles, modification strategies, and applications of several commonly used piezoelectric materials in sonodynamic therapy and prospected the future clinical applications for piezoelectric semiconductor materials in sonodynamic therapy.

Ultrasound-targeted microbubble destruction promotes PDGF-primed bone mesenchymal stem cell transplantation for myocardial protection in acute Myocardial Infarction in rats.

BACKGROUND: Ultrasound-targeted microbubble destruction (UTMD) has emerged as a promising strategy for the targeted delivery of bone marrow mesenchymal stem cells (MSCs) to the ischemic myocardium. However, the limited migration capacity and poor survival of MSCs remains a major therapeutic barrier. The present study was performed to investigate the synergistic effect of UTMD with platelet-derived growth factor BB (PDGF-BB) on the homing of MSCs for acute myocardial infarction (AMI). METHODS: MSCs from male donor rats were treated with PDGF-BB, and a novel microbubble formulation was prepared using a thin-film hydration method. In vivo, MSCs with or without PDGF-BB pretreatment were transplanted by UTMD after inducing AMI in experimental rats. The therapeutic efficacy of PDGF-BB-primed MSCs on myocardial apoptosis, angiogenesis, cardiac function and scar repair was estimated. The effects and molecular mechanisms of PDGF-BB on MSC migration and survival were explored in vitro. RESULTS: The results showed that the biological effects of UTMD increased the local levels of stromal-derived factor-1 (SDF-1), which promoted the migration of transplanted MSCs to the ischemic region. Compared with UTMD alone, UTMD combined with PDGF-BB pretreatment significantly increased the cardiac homing of MSCs, which subsequently reduced myocardial apoptosis, promoted neovascularization and tissue repair, and increased cardiac function 30 days after MI. The vitro results demonstrated that PDGF-BB enhanced MSC migration and protected these cells from H2O2-induced apoptosis. Mechanistically, PDGF-BB pretreatment promoted MSC migration and inhibited H2O2-induced MSC apoptosis via activation of the phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/Akt) pathway. Furthermore, crosstalk between PDGF-BB and stromal-derived factor-1/chemokine receptor 4 (SDF-1/CXCR4) is involved in the PI3K/AKT signaling pathway. CONCLUSION: The present study demonstrated that UTMD combined with PDGF-BB treatment could enhance the homing ability of MSCs, thus alleviating AMI in rats. Therefore, UTMD combined with PDGF-BB pretreatment may offer exciting therapeutic opportunities for strengthening MSC therapy in ischemic diseases.

Ursolic acid reduces oxidative stress injury to ameliorate experimental autoimmune myocarditis by activating Nrf2/HO-1 signaling pathway.

Background: Oxidative stress is crucial in experimental autoimmune myocarditis (EAM)-induced inflammatory myocardial injury. Ursolic acid (UA) is an antioxidant-enriched traditional Chinese medicine formula. The present study aimed to investigate whether UA could alleviate inflammatory cardiac injury and determine the underlying mechanisms. Methods: Six-week-old male BALB/c mice were randomly assigned to one of the three groups: Sham, EAM group, or UA intervention group (UA group) by gavage for 2 weeks. An EAM model was developed by subcutaneous injection of α-myosin heavy chain derived polypeptide (α-MyHC peptide) into lymph nodes on days 0 and 7. Echocardiography was used to assess cardiac function on day 21. The inflammation level in the myocardial tissue of each group was compared using hematoxylin and eosin staining (HE) of heart sections and Interleukin-6 (IL-6) immunohistochemical staining. Masson staining revealed the degree of cardiac fibrosis. Furthermore, Dihydroethidium staining, Western blot, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were used to determine the mechanism of cardioprotective effects of UA on EAM-induced cardiac injury, and the level of IL-6, Nrf2, and HO-1. Results: In EAM mice, UA intervention significantly reduced the degree of inflammatory infiltration and myocardial fibrosis while improving cardiac function. Mechanistically, UA reduced myocardial injury by inhibiting oxidative stress (as demonstrated by a decrease of superoxide and normalization of pro- and antioxidant enzyme levels). Interestingly, UA intervention upregulated the expression of antioxidant factors such as Nrf2 and HO-1. In vitro experiments, specific Nrf2 inhibitors reversed the antioxidant and antiapoptotic effects of ursolic acid, which further suggested that the amelioration of EAM by UA was in a Nrf2/HO-1 pathway-dependent manner. Conclusion: These findings indicate that UA is a cardioprotective traditional Chinese medicine formula that reduces EAM-induced cardiac injury by up-regulating Nrf2/HO-1 expression and suppressing oxidative stress, making it a promising therapeutic strategy for the treatment of EAM.

Ultrasound-Responsive Biomimetic Superhydrophobic Drug-Loaded Mesoporous Silica Nanoparticles for Treating Prostate Tumor.

Interfacial nanobubbles on a superhydrophobic surface can serve as ultrasound cavitation nuclei for continuously promoting sonodynamic therapy, but their poor dispersibility in blood has limited their biomedical application. In this study, we proposed ultrasound-responsive biomimetic superhydrophobic mesoporous silica nanoparticles, modified with red blood cell membrane and loaded with doxorubicin (DOX) (F-MSN-DOX@RBC), for RM-1 tumor sonodynamic therapy. Their mean size and zeta potentials were 232 ± 78.8 nm and -35.57 ± 0.74 mV, respectively. The F-MSN-DOX@RBC accumulation in a tumor was significantly higher than in the control group, and the spleen uptake of F-MSN-DOX@RBC was significantly reduced in comparison to that of the F-MSN-DOX group. Moreover, the cavitation caused by a single dose of F-MSN-DOX@RBC combined with multiple ultrasounds provided continuous sonodynamic therapy. The tumor inhibition rates in the experimental group were 71.5 8 ± 9.54%, which is significantly better than the control group. DHE and CD31 fluorescence staining was used to assess the reactive oxygen species (ROS) generated and the broken tumor vascular system induced by ultrasound. Finally, we can conclude that the combination of anti-vascular therapy, sonodynamic therapy by ROS, and chemotherapy promoted tumor treatment efficacy. The use of red blood cell membrane-modified superhydrophobic silica nanoparticles is a promising strategy in designing ultrasound-responsive nanoparticles to promote drug-release.

Granzyme B-responsive fluorescent probe for non-invasive early diagnosis of transplant rejection.

Allograft rejection has always been a major obstacle in organ transplantation. The current clinical diagnostic gold standard for allograft rejection is an invasive biopsy. However, biopsy has some limitations, such as sampling errors, risk of serious complications, and high cost. In this study, we have rationally developed an activatable fluorescent probe CYGB for imaging of granzyme B, which is a biomarker released by CD8+T cells attacking the graft. Moreover, the ability of CYGB to detect rejection early in mouse heart and skin transplantation models was evaluated. The probe CYGB consists of a caged hemicyanine-based fluorophore and a GzmB-specifically cleaved peptide substrate linked via a self-immolating spacer, p-aminobenzyl alcohol. Endogenous GzmB in CD8+ T cells specifically activated the near-infrared fluorescence (NIRF) signal of CYGB. In vivo imaging in mice skin and heart graft models, showed that CYGB preferentially accumulates in grafts, enabling early diagnosis of rejection. Moreover, CYGB enables non-invasive assessment of the level of immunosuppression in allogeneic mice treated with FK506. This study provides an alternative method for monitoring the status of allografts without biopsy.

Targeted microRNA delivery by lipid nanoparticles and gas vesicle-assisted ultrasound cavitation to treat heart transplant rejection.

Despite exquisite immune response modulation, the extensive application of microRNA therapy in treating heart transplant rejection is still impeded by poor stability and low target efficiency. Here we have developed a low-intensity pulsed ultrasound (LIPUS) cavitation-assisted genetic therapy after executing the heart transplantation (LIGHT) strategy, facilitating microRNA delivery to target tissues through the LIPUS cavitation of gas vesicles (GVs), a class of air-filled protein nanostructures. We prepared antagomir-155 encapsulated liposome nanoparticles to enhance the stability. Then the murine heterotopic transplantation model was established, and antagomir-155 was delivered to murine allografted hearts via the cavitation of GVs agitated by LIPUS, which reinforced the target efficiency while guaranteeing safety owing to the specific acoustic property of GVs. This LIGHT strategy significantly depleted miR-155, upregulating the suppressors of cytokine signaling 1 (SOCS1), leading to reparative polarization of macrophages, decrease of T lymphocytes and reduction of inflammatory factors. Thereby, rejection was attenuated and the allografted heart survival was markedly prolonged. The LIGHT strategy achieves targeted delivery of microRNA with minimal invasiveness and great efficiency, paving the way towards novel ultrasound cavitation-assisted strategies of targeted genetic therapy for heart transplantation rejection.

Apoptotic tumor cell-derived microparticles loading Napabucasin inhibit CSCs and synergistic immune therapy.

BACKGROUND: Cancer stem cells (CSCs) are crucial for the growth, metastasis, drug resistance, recurrence, and spread of tumors. Napabucasin (NAP) could effectively inhibit CSC, but its mechanism has not been fully explained. Additionally, NAP also has the drawbacks of poor water solubility and low utilization. Therefore, this study not only elaborated the new mechanism of NAP inhibiting CSCs, but also built NAP-loaded nanoprobes using apoptotic tumor-derived microparticles (TMPs) as carriers to combine diagnose and treat of colon cancer and lessen the adverse effects of NAP. RESULTS: The study discovered a new mechanism for NAP inhibiting tumors. NAP, in addition to inhibiting STAT3, may also inhibit STAT1, thereby inhibiting the expression of CD44, and the stemness of colon cancer. N3-TMPs@NAP was successfully synthesized, and it possessed a lipid bilayer with a particle size of 220.13 ± 4.52 nm, as well as strong tumor binding ability and anti-tumor effect in vitro. In static PET/CT imaging studies, the tumor was clearly visible and showed higher uptake after N3-TMPs@NAP injection than after oral administration. The average tumor volume and weight of the N3-TMPs@NAP group on day 14 of the treatment studies were computed to be 270.55 ± 107.59 mm3 and 0.30 ± 0.12 g, respectively. These values were significantly lower than those of the other groups. Additionally, N3-TMPs@NAP might prevent colon cancer from spreading to the liver. Furthermore, due to TMPs' stimulation of innate immunity, N3-TMPs@NAP might stimulate anti-tumor. CONCLUSIONS: As a combined diagnostic and therapeutic nanoprobe, N3-TMPs@NAP could successfully conduct PET/CT imaging, suppress CSCs, and synergistically stimulate anticancer immune responses. Additionally, this nanoprobe might someday be employed in clinical situations because TMPs for it can be produced from human tissue and NAP has FDA approval.

Low-intensity pulsed ultrasound (LIPUS) enhances the anti-inflammatory effects of bone marrow mesenchymal stem cells (BMSCs)-derived extracellular vesicles.

BACKGROUND: Bone marrow-derived mesenchymal stem cells (BMSCs)-derived extracellular vesicles (EVs) have shown potent anti-inflammatory function in various pathological conditions, such as osteoarthritis and neurodegenerative diseases. Since the number of EVs naturally secreted by cells is finite and they usually bear specific repertoires of bioactive molecules to perform manifold cell-cell communication, but not one particular therapeutic function as expected, their practical application is still limited. Strategies are needed to increase the production of EVs and enhance their therapeutic function. Recent studies have suggested that low-intensity pulsed ultrasound (LIPUS) is a promising non-invasive method to increase the secretion of EVs and promote their anti-inflammatory effects. However, the effect of LIPUS stimulation of BMSCs on EVs derived from the cells remains unclear. The objective of this study was to investigate whether LIPUS stimulation on BMSCs could increase the secretion of EVs and enhance their anti-inflammatory effects. METHODS: BMSCs were exposed to LIPUS (300 mW/cm2) for 15 min and EVs were isolated by ultracentrifugation. Anti-inflammatory effects of EVs were investigated on RAW264.7 cells in vitro and in the allogeneic skin transplantation model. Small RNA-seq was utilized to identify components difference in EVs with/without LIPUS irradiation. RESULTS: In this study, we found that LIPUS stimulation could lead to a 3.66-fold increase in the EVs release from BMSCs. Moreover, both in vitro and in vivo experimental results suggested that EVs secreted from LIPUS-treated BMSCs (LIPUS-EVs) possessed stronger anti-inflammatory function than EVs secreted from BMSCs without LIPUS stimulation (C-EVs). RNA-seq analysis revealed that miR-328-5p and miR-487b-3p were significantly up-regulated in LIPUS-EVs compare with C-EVs. The suppression of MAPK signaling pathway by these two up-regulated miRNAs could be the potential mechanism of strengthened anti-inflammatory effects of LIPUS-EVs. CONCLUSION: LIPUS stimulation on BMSCs could significantly increase the secretion of EVs. Moreover, EVs generated from LIPUS-treated BMSCs possessed much stronger anti-inflammatory function than C-EVs. Therefore, LIPUS could be a promising non-invasive strategy to promote the production of EVs from BMSCs and augment their anti-inflammatory effects.

Enhancing Doxorubicin Delivery in Solid Tumor by Superhydrophobic Amorphous Calcium Carbonate-Doxorubicin Silica Nanoparticles with Focused Ultrasound.

The current approach of delivering chemotherapy via pH-sensitive amorphous calcium carbonate-doxorubicin silica nanoparticles (ADS NPs) faces the challenge of insufficient drug dose due to drug instability within the bloodstream and poor tumor penetration. To overcome these long-standing obstacles, we proposed a superhydrophobic coating on the surface of the ADS NPs that could be easily modified via fluorination (ADSF NPs). The surface of fluorinated ADS NPs was further modified with a phospholipid layer to reduce aggregation and improve biocompatibility (ADSFL NPs). The contact angle and mean size of ADSFL NPs were 30.2 ± 4.4° and 353.1 ± 54.2 nm, respectively. The superhydrophobic layer generated interfacial nanobubbles on the outer shell of the NPs that reduced water-induced leakage of doxorubicin (DOX) sevenfold compared with the uncoated group and induced a cavitation effect upon ultrasound (US) sonication. Moreover, release of DOX from the ADSFL NPs could be triggered by US, and this release was further improved 1.6-fold in acidic aqueous conditions, indicating that the ADSFL NPs retained pH responsiveness. Enhanced sonography contrast and histological examination demonstrated that US could trigger cavitation activities from ADSFL NPs in vivo to induce vessel disruption and enhance the fluorescence intensity of DOX within the tumor region threefold under US imaging guidance compared with the ADSFL NPs-only group.

Biogenic Gas Vesicles for Ultrasound Imaging and Targeted Therapeutics.

Ultrasound is not only the most widely used medical imaging mode for diagnostics owing to its real-time, non-radiation, portable and low-cost merits, but also a promising targeted drug/gene delivery technique by producing a series of powerful bioeffects. The development of micron-sized or nanometer-sized ultrasound agents or delivery carriers further makes ultrasound a distinctive modality in accurate diagnosis and effective treatment. In this review, we introduce one kind of unique biogenic gas-filled protein nanostructures called gas vesicles, which present some unique characteristics beyond the conventional microbubbles. Gas vesicles can not only serve as ultrasound contrast agent with innovative imaging methods such as cross-amplitude modulation harmonic imaging, but also can further be adjusted and optimized via genetic engineered techniques. Moreover, they could not only serve as acoustic gene reporters, acoustic biosensors to monitor the cell metabolism, but also serve as cavitation nuclei and drug carrier for therapeutic purpose. We focus on the latest development and applications in the area of ultrasound imaging and targeted therapeutics, and also give a brief introduction to the corresponding mechanisms. In summary, these biogenic gas vesicles show some advantages over conventional MBs that deserve making more efforts to promote their development.

First aggregation-induced emission-active probe for species-specific detection of ß-galactosidase.

Sensitive detection of ß-galactosidase (ß-gal) is of great significance for early diagnosis of ovarian cancer. Fluorescent probes for detecting ß-gal have received great interest due to the non-invasiveness, excellent sensitivity, high temporal, and superior spatial resolution. However, most reported fluorescent sensors for ß-gal suffer from aggregation caused quenching effect when accumulated, and cannot discriminate ß-gal from other species, especially, Escherichia coliß-gal. Herein, we report the first aggregation-induced emission (AIE)-active fluorescent probe HBTTPAG, which achieves species-selective detection of ß-gal. Probe HBTTPAG can discriminate Aspergillus oryzae ß-gal from Escherichia coliß-gal, with high sensitivity (detection limit of 3.7 × 10-3 UmL-1), superior selectivity and low cytotoxicity. Furthermore, HBTTPAG is utilized to visualize endogenous ß-gal in lysosomes of SKOV-3 cells, as well as to detect ß-gal activity in ovarian cancer tissues. Notably, owing to the AIE-active, HBTTPAG realizes long-term (12 h) tracking ß-gal in ovarian cancer cells. This work provides a promising method for species-selective detection of ß-gal in preclinical.

Biomimetic Glucan Particles with Aggregation-Induced Emission Characteristics for Noninvasive Monitoring of Transplant Immune Response.

Real-time monitoring of post-transplant immune response is critical to prolong the survival of grafts. The current gold standard for assessing the immune response to graft is biopsy. However, such a method is invasive and prone to false negative results due to limited tissue size available and the heterogeneity of the rejection site. Herein, we report biomimetic glucan particles with aggregation-induced emission (AIE) characteristics (HBTTPEP/GPs) for real-time noninvasive monitoring of post-transplant immune response. We have found that the positively charged near-infrared AIEgens can effectively aggregate in the confined space of glucan particles (GPs), thereby turning on the fluorescence emission. HBTTPEP/GPs can track macrophages for 7 days without hampering the bioactivity. Oral administration of HBTTPEP/GPs can specially target macrophages by mimicking yeast, which then migrate to the transplant rejection site. The fluorescence emitted from HBTTPEP/GPs correlated well with the infiltration of macrophages and the degree of allograft rejection. Furthermore, a single oral HBTTPEP/GPs dose can dynamically evaluate the therapeutic response to immunosuppressive therapy. Consequently, the biomimetic AIE-active glucan particles can be developed as a promising probe for immune-monitoring in solid organ transplantation.

Noninvasive Radionuclide Molecular Imaging of the CD4-Positive T Lymphocytes in Acute Cardiac Rejection.

Heart transplantation (HT) is an effective treatment for end-stage heart disease. However, acute rejection (AR) is still the main cause of death within one year after HT. AR is an acute immune response mediated by T lymphocytes, mainly CD4+ T lymphocytes. This study innovatively develops a radiolabeled probe 99mTc-HYNIC-mAbCD4 for noninvasive visualization of CD4+ T lymphocyte infiltration and detection of AR. The 99mTc-HYNIC-mAbCD4 and its isotype control 99mTc-HYNIC-IgG were successfully prepared and characterized. The specificity and affinity of the probe in vitro were assessed by cell-binding experiments. Binding of 99mTc-HYNIC-mAbCD4 to CD4+ T lymphocytes was higher than that of the macrophages and IgG probe groups, and mAbCD4 was effective in the blockade of the binding reaction. The biodistribution data confirmed the SPECT/CT images, with significantly higher levels of 99mTc-HYNIC-mAbCD4 observed in allografts compared to allograft treatment (10 mg/kg/d Cyclosporin A subcutaneously for 5 consecutive days after surgery), isografts, or in rats which received allografts injected with 99mTc-HYNIC-IgG. Histological examination confirmed more CD4+ T lymphocyte infiltration in the allograft hearts than other groups. In summary, 99mTc-HYNIC-mAbCD4 achieved high affinity and specificity of binding to CD4+ T lymphocytes and accumulation in the transplanted heart. Radionuclide molecular imaging with 99mTc-HYNIC-mAbCD4 may be a potential diagnostic method for acute cardiac rejection.

Myocardium-targeted transplantation of PHD2 shRNA-modified bone mesenchymal stem cells through ultrasound-targeted microbubble destruction protects the heart from acute myocardial infarction.

Ultrasound-targeted microbubble destruction (UTMD) is a promising approach to facilitate the precise delivery of bone marrow stem cells (BMSCs) to the ischemic myocardium. However, stem cell therapy for ischemic myocardium is challenging due to the poor survival of transplanted stem cells under severe ischemic conditions. In this study, we investigated whether myocardium-targeted transplantation of prolyl hydroxylase domain protein 2 (PHD2) shRNA-modified BMSCs by UTMD increases the viability of grafted cells, and enhances their cardioprotective effects in acute myocardial infarction. Methods: BMSCs were transduced with lentiviral PHD2 shRNA, and a novel microbubble formulation was prepared by a thin-film hydration method. In rats, BMSCs with or without PHD2 shRNA modification were transplanted by UTMD after inducing acute myocardium infarction. Effects of PHD2 shRNA on BMSC survival, myocardial apoptosis, angiogenesis, and cardiac function were evaluated. In vitro, anti-apoptotic effects and its mechanisms of PHD2 silencing on BMSC and BMSC-conditioned medium on H9C2 cell were detected. Results: PHD2 shRNA-modified BMSC transplantation by UTMD resulted in increased BMSC survival, reduced myocardial apoptosis, reduced infarct size, increased vascular density, and improved cardiac function compared to the control vector-modified BMSC transplantation by UTMD. PHD2 silencing increased BMSC survival through a HIF-1α-dependent mechanism. The decrease in cardiomyocyte apoptosis by conditioned medium from PHD2 shRNA-treated BMSCs was due to an increase in the expression of insulin-like growth factor (IGF)-1. Conclusions: The delivery of PHD2 shRNA-modified BMSCs by UTMD promoted grafted cell homing and activity, and increased myocardial angiogenesis in the infarcted heart, leading to improved cardiac function. This combination may provide a promising strategy for enhancing the effectiveness of stem cell therapy after acute myocardial infarction.

Superhydrophobic drug-loaded mesoporous silica nanoparticles capped with ß-cyclodextrin for ultrasound image-guided combined antivascular and chemo-sonodynamic therapy.

Interfacial nanobubbles (INBs) on a superhydrophobic surface has been proposed as a solid cavitation agent for enhancing inertial cavitation dose and ultrasound contrast imaging, but the dispersibility of superhydrophobic particles limits the biomedical application. For this study, we designed superhydrophobic mesoporous silica nanoparticles loaded with the anti-tumor drug Doxorubicin (FMSNs-Dox) for tumor therapy. The ß-cyclodextrin was used to cap the superhydrophobic surface of FMSNs-Dox to reduce aggregation without inhibiting the accumulation of INBs. The mean size and a contact angle of FMSNs-Dox was 217 ± 58 nm and 129 ± 3°, respectively. The INBs cavitation on the surface of FMSNs-Dox during ultrasound sonication disrupted tumor vessels to allow a large amount of drug penetrating and trapping within tumors. The reduced tumor perfusion, histological reactive oxygen species staining, and tumor inhibition demonstrated that FMSNs-Dox sonication combined anti-vascular, sonodynamic and chemical therapies in a simple platform. Moreover, the repeatability of INB cavitation by single-injection FMSNs-Dox with multiple ultrasound sonication provided intratumoral ultrasound contrast-enhanced imaging from day 1-9 (enhancement of 3.84 ± 0.47 dB). Therefore, the characteristics of FMSNs-Dox with slow biodegradation and acoustic-sensitivity presented intratumoral day-scaled lifetime to provide a probability of repeated combination therapy by single-injection.

Bazedoxifene Regulates Th17 Immune Response to Ameliorate Experimental Autoimmune myocarditis via Inhibition of STAT3 Activation.

Myocarditis is a type of inflammatory cardiomyopathy that has no specific treatment. Accumulating evidence suggests that Th17 cells play a prominent role in the pathogenesis of myocarditis. Interleukin-(IL)-6-mediated signal transducer and activation of transcription 3 (STAT3) signaling is essential for Th17 cell differentiation and secretion of inflammatory cytokines. Bazedoxifene inhibits IL-6/STAT3 signaling in cancer cells, but its effect on the Th17 immune response induced by myocarditis remains unknown. Here we explore the effect of Bazedoxifene on Th17 immune response and cardiac inflammation in a mouse model of experimental autoimmune myocarditis, which has been used to mimic human inflammatory heart disease. After eliciting an immune response, we found Bazedoxifene ameliorated cardiac inflammatory injury and dysfunction. Th17 cells and related inflammatory factors in splenic CD4+ T cells at day 14 and in the heart at day 21 were increased, which were reduced by Bazedoxifene. Furthermore, Bazedoxifene could regulate autophagy induction in polarized Th17 cells. In conclusion, Bazedoxifene affected STAT3 signaling and prevented cardiac inflammation deterioration, so may provide a promising therapeutic strategy for the treatment of experimental autoimmune myocarditis (EAM).

Improving acute cardiac transplantation rejection therapy using ultrasound-targeted FK506-loaded microbubbles in rats.

Targeted delivery of immunosuppressants to allografts can increase the concentrations of drugs in pathological tissues, improve therapeutic effects and reduce unfavorable side effects. Therefore, we synthesized FK506-loaded microbubbles (FK506-MBs) for site-specific release of FK506 into transplanted hearts by the ultrasound-targeted microbubble destruction (UTMD) technique. The average particle size of FK506-MBs was 1.65 ± 0.32 µm and they had high drug loading and encapsulation efficiency. The in vivo drug concentration in transplanted hearts that were treated with FK506-MBs plus UTMD was about 1.64-fold higher than that in grafts that received free FK506 at the same dosage. The degree of graft rejection in the FK506-MB plus UTMD group was lower than those of other groups. Both infiltration of T cells and secretion of inflammatory cytokines were significantly reduced in the FK506-MB plus UTMD group. More importantly, the mean survival time of the grafts was significantly longer (16.00 ± 0.89 day) than those of the PBS group (6.66 ± 1.36 day) and the FK506 group (12.83 ± 1.17 day). In addition, we also found that the concentration of FK506 in whole blood was lower in the FK506-MB plus UTMD group than that in the FK506 group, which would be beneficial for reducing the side effects. Hence, our results showed that combining FK506-MBs with UTMD was an effective strategy to deliver FK506 to transplanted hearts, which can increase the local drug concentration and enhance its efficacy on rejection. Ultrasound-targeted drug release is safe and radiation-free, with great potential for clinical transformation, and could also be extended to the treatment of other graft rejection cases, such as liver transplantation, kidney transplantation and so on.

Image-Guided Hydrogen Gas Delivery for Protection from Myocardial Ischemia-Reperfusion Injury via Microbubbles.

Cardiomyocyte death induced by ischemia-reperfusion is a major cause of morbidity and mortality worldwide. Hydrogen (H2), as an antioxidant, has been shown to have great potential in preventive and therapeutic applications against lethal injury that occurs from ischemia-reperfusion. However, H2 is sparingly soluble in water, resulting in its poor bioavailability in blood and damaged tissues. Here, we have developed an ultrasound-visible H2 delivery system by loading H2 inside microbubbles (H2-MBs) to prevent myocardial ischemia-reperfusion injury. Using this system, the concentration of H2 in unit volume can be greatly improved under normal temperature and pressure conditions. H2-MBs can be visually tracked with ultrasound imaging systems and can effectively release their therapeutic gas. In vivo systemic delivery of H2-MBs in myocardial ischemic rats at the start of reperfusion resulted in a significant reduction of infarct size and pathological remodeling. Further analysis showed that this approach markedly inhibited cardiomyocyte apoptosis and reduced myocardial inflammation and oxidant damage in myocardial ischemia-reperfusion rats. These results indicate that H2-MBs are a promising visual delivery system for H2-based therapeutic applications.

Reversal of multidrug resistance phenotype in human breast cancer cells using doxorubicin-liposome-microbubble complexes assisted by ultrasound.

The circumvention of multidrug resistance (MDR) plays a critically important role in the success of chemotherapy. The aim of this work is to investigate the effectiveness and possible mechanisms of the reversal of MDR phenotype in human breast cancer cells by using doxorubicin-liposome-microbubble complexes (DLMC) assisted by ultrasound (US). DLMC is fabricated through conjugating doxorubicin (DOX)-liposome (DL) to the surface of microbubbles (MBs) via the biotin-avidin linkage. The resulting drug-loaded complexes are then characterized and incubated with MCF-7/ADR human breast cancer cells and followed by US exposure. Our results show the more rapid cellular uptake, evident enhancement of nuclear accumulation and less drug efflux in the resistant cells treated by DLMC+US than those treated by DL, DL+verapamil under the same US treatment or DLMC without US. The enhanced drug delivery and cellular uptake also associated with the increase of cytotoxicity against MCF-7/ADR cells, lower MCF-7/ADR cell viability and higher apoptotic cells. Mechanism investigations further disclose a significant increase of reactive oxygen species (ROS) level, enhanced DNA damage and obvious reduction of P-glycoprotein expression in the resistant cells treated with DLMC+US compared with the control cases of cells treated by DLMC, DL+US or DL+verapamil+US. In conclusion, our study demonstrates that DLMC in combination with US may provide an effective delivery of drug to sensitize cells to circumvent MDR and to enhance the therapeutic index of the chemotherapy.

A novel microfluidic chip for assessing dynamic adhesion behavior of cell-targeting microbubbles.

The primary aim of this study was to develop a microfluidic chip to study the dynamic adhesion behavior of cell-targeted microbubbles. The microfluidic device is composed of polydimethylsiloxane and is fabricated using the soft lithography technique. Each chamber of the microfluidic chip comprises eight U-shaped microsieves, by which various flow velocity distributions are generated. LyP-1-conjugated microbubbles were prepared by coating the surface of the phospholipid shell of microbubbles with LyP-1 peptides via biotin-avidin linkage. Under static conditions, the resulting targeted microbubbles are able to bind onto the surface of cells on incubation with breast cancer cells. Under dynamic fluid conditions, the cell targeting efficiency of the microbubbles was assessed at various flow velocity distributions in a chamber. Accumulation of targeted microbubbles was strongly influenced by flow velocity. Better retention of targeted microbubbles on cell surfaces was achieved at low mean flow velocities (<0.03 cm/s), in agreement with our computer simulation results. In conclusion, our results indicate that the microfluidic system is a useful platform for studying the microbubble-cell adhesive interaction.