Low-intensity Ultrasound Research Articles

Modeling Intracellular Ca<sup>2+</sup> Transient Induced by Low-Intensity Ultrasound

Modeling Intracellular Ca<sup>2+</sup> Transient Induced by Low-Intensity Ultrasound

Effects of Low-Intensity Ultrasound on Oxidative Damage in Retinal Pigment Epithelial Cells in vitro

Oxidative stress in retinal pigment epithelium (RPE) is one of the key causative factors of RPE injury in age-related macular degeneration (AMD). Low-intensity ultrasound (LIUS) less than 1 W/cm2 in intensity has been found to have cytoprotective and anti-inflammatory effects in many cell types and diseases. In this study, we investigated for the first time the feasibility of using LIUS to protect RPE cells from oxidative damage. ARPE-19 cells were treated with H2O2 (an exogenous source of reactive oxygen species) or L-buthionine-(S,R)-sulfoximine (BSO), a glutathione synthase inhibitor, and exposed immediately to LIUS at intensities of 50, 100 and 200 mW/cm2 and a frequency of 1 MHz for 20 min. Both H2O2 and BSO increased the percentage of cells positive for mitochondrial reactive oxygen species at 1 h, but not at 24 h. Co-treatment with LIUS clearly repressed these cells similarly at all intensities by approximately 34%–43% for H2O2 and 24%–25% for BSO (p < 0.05). The percentage of cells with mitochondrial membrane depolarization also increased with H2O2 and BSO treatment, particularly at 1 h, and decreased by approximately 60% with LIUS at 100 mW/cm2 (p < 0.05). The amount of intracellular calcium ion ([Ca2+]i) was elevated only by BSO at 24 h and was also significantly diminished, by approximately 45%, by LIUS at 100 mW/cm2 (p < 0.05). Both H2O2 and BSO significantly hampered cell viability at 24 h, but LIUS at 100 mW/cm2 restored only BSO-induced cell viability by approximately 2.7-fold (p < 0.05). This study illustrated that LIUS has a protective effect on RPE cells against oxidative damage caused by BSO, an endogenous mitochondrial reactive oxygen species generator. We speculate that LIUS has the potential to treat oxidative damage and related pathologic changes in RPE.

Bioeffects of Transient and Low-Intensity Ultrasound on Nanoparticles for a Safe and Efficient DNA Delivery

An important advantage of polymer-based gene delivery systems over viral transfection systems is that transient gene expression without the safety concerns can be achieved. In addition to the polymeric systems to deliver DNA, therapeutic ultrasound is potentially useful because ultrasound energy can be transmitted through the body without damaging tissues and could be applied on a restricted area where the desired DNA is to be expressed. In this study, bioeffects of ultrasound on the transfection efficiency and cytotoxicity of DNA-polymer complexes on mammalian cells (HEK-293 and COS-7 cell lines) were investigated. Polymer-DNA ratios for optimal transfection efficiency and the size of PEI/DNA or PDMAEMA/DNA complexes were found not affected by ultrasound treatment. Also, electrophoresis results indicate that the tertiary DNA structure was not influenced by ultrasound when exposed up to 10 seconds. More importantly, cationic polymer-mediated cell transfection was significantly enhanced and reached a 150% increase by using ultrasound. Cytotoxicity of HEK-293 and COS-7 cell lines was not observed after ultrasound. Therefore, these results indicate that clinical applications of ultrasound could be used as a safe and efficient method for non-viral gene delivery

Enhanced downregulation of transforming growth factor‑β2 in rat retinal pigment epithelium cells by adeno‑associated virus‑mediated ribonucleic acid interference combined with ultrasound or microbubbles.

The present study was designed to determine the efficiency and safety of ultrasound (US) and/or US contrast agent microbubbles (MBs) in the delivery of type 2 recombinant adeno-associated virus‑delivered transforming growth factor‑β2 short hairpin ribonucleic acid encoding the enhanced green fluorescent protein gene (rAAV2‑TGFβ2 shRNA‑EGFP) and the downregulation of TGFβ2 in rat retinal pigment epithelium (RPE‑J) cells. The effects of US and/or MBs on the delivery of rAAV2‑EGFP and rAAV2‑TGFβ2 shRNA‑EGFP were evaluated by fluorescence microscopy and flow cytometry. The potential toxicity of cell viability under various US or MB conditions was assessed by CellTiter 96® AQueous One solution cell proliferation assay. The level of TGFβ2 mRNA in RPE‑J cells under various conditions was estimated by reverse transcription‑quantitative polymerase chain reaction analysis. The results obtained demonstrated that low-intensity US (0.5 W/cm2 and 30 sec) or SonoVue (MB:cell ratio, 40:1) increased the delivery efficiency of rAAV2‑EGFP and rAAV2‑TGFβ2 shRNA‑EGFP to RPE‑J cells, whereas the combination of US with MBs did not further increase but instead decreased rAAV transfection. Under the optimal conditions of rAAV delivery, enhanced TGFβ2 gene silencing with a combination of US or SonoVue with rAAV2‑TGFβ2 shRNA resulted in a significant decrease in mRNA levels compared with rAAV2‑TGFβ2 shRNA alone. US or SonoVue was used safely to enhance the delivery of rAAV2‑TGFβ2 shRNA to RPE‑J cells. A combination of the biological (rAAV2‑TGFβ2 shRNA) and physical (US or SonoVue) approaches downregulated the mRNA level of TGFβ2 more effectively.

Differentiation of Neural Stem/Progenitor Cells Using Low-Intensity Ultrasound

Herein, we report the evaluation of apoptosis, cell differentiation, neurite outgrowth and differentiation of neural stem/progenitor cells (NSPCs) in response to low-intensity ultrasound (LIUS) exposure. NSPCs were cultured under different conditions, with and without LIUS exposure, to evaluate the single and complex effects of LIUS. A lactic dehydrogenase assay revealed that the cell viability of NSPCs was maintained with LIUS exposure at an intensity range from 100 to 500 mW/cm2. Additionally, in comparison with no LIUS exposure, the cell survival rate was improved with the combination of medium supplemented with nerve growth factor and LIUS exposure. Our results indicate that LIUS exposure promoted NSPC attachment and differentiation on a glass substrate. Neurite outgrowth assays revealed the generation of longer, thicker neurites after LIUS exposure. Furthermore, LIUS stimulation substantially increased the percentage of differentiating neural cells in NSPCs treated with nerve growth factor in comparison with the unstimulated group. The high percentage of differentiated neural cells indicated that LIUS induced neuronal networks denser than those observed in the unstimulated groups. Furthermore, the release of nitric oxide, an important small-molecule neurotransmitter, was significantly upregulated after LIUS exposure. It is therefore reasonable to suggest that LIUS promotes the differentiation of NSPCs into neural cells, induces neurite outgrowth and regulates nitric oxide production; thus, LIUS may be a potential candidate for NSPC induction and neural cell therapy.

Study on SBR Enhanced by Low Intensity Ultrasound for Treatment of Chemical Production Wastewater

In this paper, activated sludge process enhanced by ultrasound was applied to treat the chemical production wastewater containing nitroaromatic compound after ultrasonic pretreatment. The factors influence to treatment effect such as ultrasound power and frequency, irradiation time were investigated by experiment. The mechanism of ultrasound enhanced activated sludge process was analyzed. The experimental results show that ultrasonic irradiation with appropriate parameters can effectively enhance sludge activity, improve the treatment efficiency. The optimal treatment conditions are as follows: ultrasound power 10W, frequency 25kHz, irradiation time 15min.

Effects of low-intensity ultrasound on gramicidin D-induced erythrocyte edema.

To determine whether low-intensity ultrasound (US) can reduce red blood cell (RBC) edema and, if so, whether the US activity is associated with aquaporin 1 (AQP-1), a water channel in the cell membrane. Red blood cell edema was induced by gramicidin D treatment at 40 ng/mL for 20 minutes and evaluated by a hematocrit assay. Low-intensity continuous wave US at 1 MHz was applied to RBCs for the last 10 minutes of gramicidin D treatment. To determine whether US activity was associated with AQP-1, RBCs were treated with 40 μM mercuric chloride (HgCl(2)), an AQP-1 inhibitor, for 20 minutes at the time of gramicidin D treatment. Posttreatment morphologic changes in RBCs were observed by actin staining with phalloidin. Red blood cell edema increased significantly with gramicidin D at 20 (1.8%), 40 (6.7%), 60 (16.7%), and 80 (11.3%) ng/mL, reaching a peak at 60 ng/mL, compared to the control group (20 ng/mL, P = .019; 40, 60, and 80 ng/mL, P < .001). No significant RBC hemolysis was observed in any group. Edema induced by gramicidin D at 40 ng/mL was significantly reduced by US at 30 (3.4%; P = .003), 70 (4.4%; P = .001), and 100 (2.9%; P = .001) mW/cm(2). Subsequent experiments showed that edema reduction by US ranged from 7% to 10%. Cotreatment with HgCl(2) partially reversed the US effect and showed a significantly different level of edema compared to gramicidin D-alone and US-cotreated groups (P = .001). These results were confirmed by microscopic observation of RBC morphologic changes. Low-intensity US could reduce gramicidin D-induced RBC edema, and its effect appeared to at least partly involve regulation of AQP-1 activity. These results suggest that low-intensity US can be used as an alternative treatment to control edema and related disorders.

Enhancement of the cytotoxicity and selectivity of doxorubicin to hepatoma cells by synergistic combination of galactose-decorated γ-poly(glutamic acid) nanoparticles and low-intensity ultrasound.

Specific drug delivery to solid tumors remains one of the challenges in cancer therapy. The aim of this study was to combine three drug-targeting strategies, polymer-drug conjugate, ligand presentation and ultrasound treatment, to enhance the efficacy and selectivity of doxorubicin (DXR) to hepatoma cells. The conjugation of DXR to γ-poly(glutamic acids) (γ-PGA) decreased the cytotoxicity of DXR, while the conjugation of galactosamine (Gal) to the γ-PGA-DXR conjugate restored the cytotoxic efficacy of DXR on hepatoma cells due to increased uptake of DXR. Furthermore, low-intensity ultrasound treatment increased the cell-killing ability of γ-PGA-DXR conjugates by 20%. The in vitro results showed the potential of the γ-PGA-DXR-Gal conjugate for future clinical applications.

Increase of Proliferation and Colonization in Mouse Spermatogonial Stem Cell by Low Intensity Ultrasound

Background Spermatogonial stem cells (SSCs) are the foundation of spermatogenesis. Sound wave especially low intensity ultrasound (LIUS) can be effective on increasing the number of cells. In this study we investigated the effect of LIUS stimulation on mouse SSCs proliferation and colonization. Methods: Isolated SSCs from neonate mice cultured in DMEM culture medium with 10% Fetal Bovine Serum. In the first phase of study, temperature controlled and in the second phase, SSCs stimulated by LIUS with 3 different Intensity dose (100, 200 and 300 mW/cm2) for 5 day and SSCs proliferation and colonization assessed at 7th day. Results: The LIUS treatment of mouse SSCs increased the proliferation rate and colonization of SSCs in experimental groups compared to the control group. Average of proliferation rate in 100, 200, 300 mW/cm2 and control group were 1.96 ± 0.03, 2.26 ± 0.03, 1.73 ± 0.03 and 1.66 ± 0.03, respectively. Average number of colonies in 100, 200,300 mW/cm2 and control group were 45 ± 1.2, 53 ± 2.4, 28 ± 1.2 and 20 ± 0.8, respectively. Average diameters of colonies in 100, 200, 300 mW/cm2 and control group were 235.3 ± 6.8 µm, 204.6 ± 12.3 µm, 203.6 ± 5.6 and 214.3 ± 9.1 µm, respectively. Our results showed that there was significant increase in proliferation rate and number of colonies in experimental groups compared to control group (P<0.05), whereas there were not significant differences between groups regarding to diameter of colonies. Conclusion: These results suggested that LIUS treatment can be an efficient and cost-effective method to improve proliferation and colonization of SSCs during in vitro culture. Key words: colonization, proliferation, mouse, Stem Cell, Ultrasound.

Hemostatic effects of microbubble-enhanced low-intensity ultrasound in a liver avulsion injury model.

ObjectivesMicrobubble-enhanced therapeutic ultrasound (MEUS) can block the blood flow in the organs. The aim of this study was to evaluate the hemostatic effect of microbubble-enhanced pulsed, low-intensity ultrasound in a New Zealand White rabbit model of avulsion trauma of the liver. The therapeutic ultrasound (TUS) transducer was operated with the frequency of 1.2 MHz and an acoustic pressure of 3.4 MPa. Microbubble-(MB) enhanced ultrasound (MEUS) (n = 6) was delivered to the distal part of the liver where the avulsion was created. Livers were treated by TUS only (n = 4) or MB only (n = 4) which served as controls. Bleeding rates were measured and contrast enhanced ultrasound (CEUS) was performed to assess the hemostatic effect, and liver hemoperfusion before and after treatment. Generally, bleeding rates decreased more than 10-fold after the treatment with MEUS compared with those of the control group (P<0.05). CEUS showed significant declines in perfusion. The peak intensity value and the area under the curve also decreased after insonation compared with those of the control group (P<0.05). Histological examination showed cloudy and swollen hepatocytes, dilated hepatic sinusoids, perisinusoidal spaces with erythrocyte accumulation in small blood vessels, obvious hemorrhage around portal areas and scattered necrosis in liver tissues within the insonation area of MEUS Group. In addition, necrosis was found in liver tissue 48 h after insonation. We conclude that MEUS might provide an effective hemostatic therapy for serious organ trauma such as liver avulsion injury.

Inhibitory effects of subcutaneous tumors in nude mice mediated by low-frequency ultrasound and microbubbles.

The aim of the present study was to investigate the sonication effects of 21-kHz ultrasound (US) with microbubbles (MBs) on the subcutaneous prostate tumors of nude mice. In total, 15 tumor-bearing nude mice were divided into three groups: The control group, the low-frequency US group and the US+MB group. The MBs used were from US contrast agent SonoVue. The parameters of the US were as follows: 21 kHz, 26 mW/cm2 and a 40% duty cycle (2 sec on, 3 sec off) for 3 min, once every other day for 2 weeks. Color Doppler flow imaging, hematoxylin and eosin (HE) staining, immunoblotting and transmission electron microscopy (TEM) were used to evaluate the results. Following 2 weeks of treatment, the blood flow signal disappeared in the US+MB group only, and the tumor size was smaller when compared with the control and US groups. For the immunoblotting, the intensity of cyclooxygenase-2 and vascular endothelial growth factor in the US+MB group was lower compared with the other two groups. Tumor necrosis was present and the nucleus disappeared upon HE staining in the US+MB group. Upon TEM analysis, increased cytoplasmic vacuolation and dilatation of the perinuclear cisternae of the tumor cells were found in the US+MB group. In the control and US groups, the tumors had intact vascular endothelia and vessel lumens. However, lumen occlusion of the vessels was observed in the US+MB group. In conclusion, 21-kHz low-intensity US with MBs may result in vessel occlusion and growth inhibitory effects in the subcutaneous tumors of nude mice.

Enhancement of Adenovirus Delivery after Ultrasound-Stimulated Therapy in a Cancer Model

Improving the efficiency of adenovirus (Ad) delivery to target tissues has the potential to advance the translation of cancer gene therapy. Ultrasound (US)-stimulated therapy uses microbubbles (MBs) exposed to low-intensity US energy to improve localized delivery. We hypothesize that US-stimulated gene therapy can improve Ad infection in a primary prostate tumor through enhanced tumor uptake and retention of the Ad vector. In vitro studies were performed to analyze the degree of Ad infectivity after application of US-stimulated gene therapy. A luciferase-based Ad on a ubiquitous cytomegalovirus (CMV) promoter (Ad5/3-CMV-Luc) was used in an animal model of prostate cancer (bilateral tumor growth) to evaluate Ad transduction efficiency after US-stimulated therapy. Bioluminescence imaging was employed for in vivo analysis to quantify Ad infection within the tumor. In vitro studies revealed no difference in Ad transduction between groups receiving US-stimulated therapy using high, low or sham US intensity exposures at various multiplicities of infection (MOIs) (p = 0.80). In vivo results indicated that tumors receiving US-stimulated therapy after intra-tumoral injection of Ad5/3-CMV-Luc (1 × 10(6) plaque-forming units) exhibited a 95.1% enhancement in tumor delivery compared with control tumors receiving sham US (p = 0.03). US-stimulated therapy has significant potential to immediately affect Ad-based cancer gene therapy by improving virus bioavailability in target tissues.

Biohydrogen Production by Co-Fermentation of Starch Wastewater and Sludge under Thermophilic Condition

In this paper, the possibility and potential of biohydrogen production by co-fermentation of starch wastewater (SW) and WAS under thermophilic temperature was studied in batch fermentation tests. WAS was first pretreated by thermophilic enzyme together with low intensity ultrasound (LIU) to improve the biochemical degradability. Then After 8 h pretreatment, all soluble substances were much higher than raw sludge without pretreatment. In addition, the SCOD, carbohydrate and protein of the tests which were accelerated by low-frequency ultrasound were 11.5% 18.4%, 17.8% higher than the control, respectively. Results from the co-fermentation further demonstrated that the sludge had high pH buffering capacity. A mixing ratio of 1:1 was found to be the best among of all co-fermentation tests. Moreover it was proved in this study that hydrogen production by co-fermentation of starch wastewater and sludge was a promising technology to recovery energy from the waste.

Low Intensity Ultrasound Promotes the Sensitivity of Rat Brain Glioma to Doxorubicin by Down-Regulating the Expressions of P-Glucoprotein and Multidrug Resistance Protein 1 In Vitro and In Vivo

The overall prognosis for malignant glioma is extremely poor, and treatment options are limited in part because of multidrug resistant proteins. Our previous findings suggest low intensity ultrasound (LIUS) can induce apoptosis of glioma cells. Given this finding, we were interested in determining if LIUS could help treat glioma by inhibiting multidrug resistant proteins, and if so, which pathways are involved. In this study, the toxicity sensitivity and multidrug resistance proteins of glioma induced by LIUS were investigated using CCK-8, immunohistochemistry, immunofluorency, and RT-PCR in tissue samples and cultured cells. LIUS inhibited increase of C6 cells in an intensity- and time-dependent manner. The toxicity sensitivity of C6 cells increased significantly after LIUS sonication (intensity of 142.0 mW/cm2) or Doxorubicin (DOX) at different concentration, particularly by the combination of LIUS sonication and DOX. The expressions of P-gp and MRP1 decreased significantly post-sonication at intensity of 142.0 mW/cm2 both in vitro and in vivo. The expressions of p110 delta (PI3K), NF-κB-p65, Akt/PKB, and p-Akt/PKB were downregulated by LIUS sonication and DOX treatment separately or in combination at the same parameters in rat glioma. These results indicate that LIUS could increase the toxicity sensitivity of glioma by down-regulating the expressions of P-gp and MRP1, which might be mediated by the PI3K/Akt/NF-κB pathway.

Elucidating the effects of low-intensity ultrasound on mesenchymal stem cell proliferation and viability

The effects of low-intensity ultrasound (LIUS) on the proliferation, viability and extracellular matrix (ECM) production of mesenchymal stem cells (MSCs) were investigated. Continuous-wave ultrasound was applied at 1 MHz and and 350 mW/cm2 to microwells, using a LIUS system assembled in the laboratory. Needle hydrophone mapping showed that pressure amplitudes ranged from 0.015 MPa at the well edge to 0.080 MPa at the center. The LIUS group received US for 10, 20, and 30 min/day for one week. Assays were performed daily. Relative to control, 10 and 20 min LIUS very significantly stimulated MSC proliferation and ECM synthesis, while 30 min LIUS had a significant adverse effect. The phenomenon that LIUS accelerates MSC proliferation, but only for appropriate exposures, has been noted previously in the literature. However, the actual relation between the physical forces generated by the LIUS and this phenomenon remains unknown. The fluid flow pattern created by LIUS was studied by injecting dye in the well and Eckart-streaming-like motions were observed, while thermal effects were negligible. By employing LIUS with appropriate focusing and parameters, it might be possible to exploit MSCs for tissue engineering, independently of biochemical stimuli, and in a highly spatially organized manner.

Potentiation of Scutellarin on Human Tongue Carcinoma Xenograft by Low-Intensity Ultrasound

Scutellarin 7-O-β-d-glucuronide (scutellarin) has shown great potential as a chemotherapeutic agent for cancer treatment, but only at high dosage. Here we investigate the possibility of using low intensity ultrasound to reduce the scutellarin dosage. Ultrasound intensities of 1.0 W/cm2 and 0.05 W/cm2 were used for in vivo and in vitro experiments, respectively, and a very low dosage of scutellarin (15 nM) was used. Tumor-bearing Balb/c mice and SAS human-tongue squamous carcinoma cell suspensions were used for the in vivo and in vitro experiments, respectively. Each kind of subjects was divided into control, ultrasound-alone, scutellarin-alone, and combined ultrasound-scutellarin treatment groups. Only the combined treatment showed strong anticancer effects. In the in vivo case, the combined treatment significantly delayed tumor growth, initiated cellular chromatin changes (including a decrease in the number of cytoplasmic organelles and fragmentation of condensed nuclear chromatin), inhibited tumor angiogenesis and lymphangiogenesis, stopped cancer-cell proliferation, decreased MMP-2 and MMP-9 expression levels and caused cancer-cell apoptosis. In the in vitro case, the combined treatment produced cancer cell-shape irregularity in a manner seriously fractured microvilli, inhibited cancer-cell migratory and invasion activities, and induced cancer-cell apoptosis. Because the combined treatment did not increase intracellular ROS production, scutellarin is not a sonosensitizer so that the anticancer effect is not through sonodynamic therapy. Low-intensity ultrasound is merely increasing the permeability of scutellarin into cancer cells. Based on our results, one may perform localized chemotherapy using much reduced dosage of the drug with the help of low intensity ultrasound, which will greatly minimize side effects.

Mechanical Stimulation by Ultrasound Enhances Chondrogenic Differentiation of Mesenchymal Stem Cells in a Fibrin-Hyaluronic Acid Hydrogel

Chondrogenic differentiation and cartilage tissue formation derived from stem cells are highly dependent on both biological and mechanical factors. This study investigated whether or not fibrin-hyaluronic acid (HA) coupled with low-intensity ultrasound (LIUS), a mechanical stimulation, produces an additive or synergistic effect on the chondrogenesis of rabbit mesenchymal stem cells (MSCs) derived from bone marrow. For the purpose of comparison, rabbit MSCs were first cultured in fibrin-HA or alginate hydrogels, and then subjected to chondrogenic differentiation in chondrogenic-defined medium for 4 weeks in the presence of either transforming growth factor-beta3 (TGF-β3) (10 ng/mL) or LIUS treatment (1.0 MHz and 200 mW/cm(2) ). The resulting samples were evaluated at 1 and 4 weeks by histological observation, chemical assays, and mechanical analysis. The fibrin-HA hydrogel was found to be more efficient than alginate in promoting chondrogenesis of the MSCs by producing a larger amount of sulfated glycosaminoglycans (GAGs) and collagen, and engineered constructs made with the hydrogel demonstrated higher mechanical strength. At 4 weeks of tissue culture, the chondrogenesis of the MSCs in fibrin-HA were shown to be further enhanced by treatment with LIUS, as observed by analyses for the amounts of GAGs and collagen, and mechanical strength testing. In contrast, TGF-β3, a well-known chondrogenic inducer, showed a marginal additive effect in the amount of collagen only. These results revealed that LIUS further enhanced chondrogenesis of the MSCs cultured in fibrin-HA, in vitro, and suggested that the combination of fibrin-HA and LIUS is a useful tool in constructing high-quality cartilage tissues from MSCs.

What Has Low-Intensity Ultrasound Informed Us about Wheat Flour Dough Rheology?

The role of rheology in understanding the process behavior of dough and its predictive capacity with respect to breadmaking quality is of long-standing interest to cereal scientists. Over the past 12 years, we have undertaken a comprehensive examination of the rheology of wheat flour doughs using low-intensity ultrasound. Propagating shear waves at ultrasonic frequencies in conjunction with small-strain shear rheometry allowed us to show how a very broad distribution of relaxation times is necessary to define the complex shear modulus of wheat flour dough. When propagating longitudinal ultrasonic waves, three distinct regions are seen in the ultrasonic spectrum arising from the presence of bubbles in the dough. At low frequencies, where the properties of the bubbles–dough matrix “composite” are probed, the rheology of air-mixed doughs contrasts markedly with that of doughs mixed under vacuum. Therefore, all dough rheology is affected by the bubbles within the dough.

Development of a Cancer Treatment with Low-Intensity Ultrasound

Copyright: © 2013 Emoto M. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. In recent years, research on the usage of ultrasound for cancer treatment has developed and while high intensity focused ultrasound (HIFU, FUS) has already been clinically applied to several types of cancers, it is not yet considered as an established treatment. On the other hand, studies using ultrasound energy for cancer treatment have advanced, thus revealing the enhancement of drug effects by employing low-intensity ultrasound. Furthermore, anti-angiogenesis against tumors is now attracting attention as a new cancer treatment. Therefore, our research focused on the biological effects and the enhancement of drug effects brought by this low-intensity ultrasound energy and reported on the efficacy against a uterine sarcoma model, by implementing the basic studies, for the first time, including the concomitant use of low-intensity ultrasound irradiation, as an expected new antiangiogenic therapy for cancer treatment. Furthermore, we have succeeded in simultaneously utilizing low-intensity ultrasound in both diagnosis and treatment, upon real time evaluation of the anti-tumor effects and anti-angiogenesis effects using color Doppler ultrasound imaging [1].

Optimizing a novel method for low intensity ultrasound in chondrogenesis induction

Background:Hyaline cartilage tissue of joints is susceptible to injuries due to avascularity. Mesenchymal stem cells (MSCs) are used for cartilage tissue engineering. Among MSCs, adipose stem cells (ASCs) are attractive because of accessibility, their large number, and rapid growth. Common in vitro protocols successfully induce chondrogenic differentiation by expression of multiple cartilage-specific molecules. However, transforming growth factor β (TGFβ) promotes chondrogenesis to terminal stages. Despite much attention being given to the influences of biochemical factors on chondrogenesis of MSCs, few studies have examined the chondrogenic effect of mechanical factors such as ultrasound as a feasible tool.Materials and Methods:In this study, we focused on inducing chondrogenesis in the early stages of differentiation by using low-intensity ultrasound (LIUS). Four groups of ASC pellets (control, ultrasound, TGFβ, and ultrasound/TGF) were cultured under chondrogenic (10 ng/ml of TGFβ3) and ultrasound conditions (200 mW/cm2, 10 min/day). After 2 weeks, differentiation was evaluated by histology, quantitative gene expression analysis, and immunohistochemistry.Results:Our data demonstrated that ultrasound differentiated pellets showed increased expression of early chondrogenesis marker, Col2A, than those in TGFβ groups (P < 0.001), and Col2B and Col10 expression were more prominent in TGFβ groups. Immunostaining of sections showed Col2 fibrils around lacuna in LIUS and TGFβ treated groups.Conclusion:Using LIUS resulted in early chondrogenesis in comparison with terminally differentiated chondrocytes by TGFβ. Therefore, LIUS might provide an applicable, safe, efficient, and cheap tool for chondrogenic differentiation of ASCs in cartilage tissue engineering.