Xi Xiang

Targeted gene delivery to the synovial pannus in antigen-induced arthritis by ultrasound-targeted microbubble destruction in vivo

The purpose of this study was to optimize an ultrasound-targeted microbubble destruction (UTMD) technique to improve the in vivo transfection efficiency of the gene encoding enhanced green fluorescent protein (EGFP) in the synovial pannus in an antigen-induced arthritis rabbit model. A mixture of microbubbles and plasmids was locally injected into the knee joints of an antigen-induced arthritis (AIA) rabbits. The plasmid concentrations and ultrasound conditions were varied in the experiments. We also tested local articular and intravenous injections. The rabbits were divided into five groups: (1) ultrasound+microbubbles+plasmid; (2) ultrasound+plasmid; (3) microbubble+plasmid; (4) plasmid only; (5) untreated controls. EGFP expression was observed by fluorescent microscope and immunohistochemical staining in the synovial pannus of each group. The optimal plasmid dosage and ultrasound parameter were determined based on the results of EGFP expression and the present and absent of tissue damage under light microscopy. The irradiation procedure was performed to observe the duration of the EGFP expression in the synovial pannus and other tissues and organs, as well as the damage to the normal cells. The optimal condition was determined to be a 1-MHz ultrasound pulse applied for 5 min with a power output of 2 W/cm(2) and a 20% duty cycle along with 300 μg of plasmid. Under these conditions, the synovial pannus showed significant EGFP expression without significant damage to the surrounding normal tissue. The EGFP expression induced by the local intra-articular injection was significantly more increased than that induced by the intravenous injection. The EGFP expression in the synovial pannus of the ultrasound+microbubbles+plasmid group was significantly higher than that of the other four groups (P<0.05). The expression peaked on day 5, remained detectable on day 40 and disappeared on day 60. No EGFP expression was detected in the other tissues and organs. The UTMD technique can significantly enhance the in vivo gene transfection efficiency without significant tissue damage in the synovial pannus of an AIA model. Thus, this could become a safe and effective non-viral gene transfection procedure for arthritis therapy.

Power Doppler Ultrasound Evaluation of Peripheral Joint, Entheses, Tendon, and Bursa Abnormalities in Psoriatic Patients: A Clinical Study

Objective. To evaluate the prevalence rates of peripheral joint, enthesis, tendon, and bursa abnormalities by power Doppler (PD) ultrasonic examination in patients with psoriatic arthritis (PsA), psoriatic patients without clinical signs of arthritis (non-PsA psoriasis group), and healthy individuals, to detect subclinical PsA. Methods. A total of 253 healthy volunteers, 242 non-PsA psoriatic patients, and 86 patients with PsA were assessed by 2-dimensional and power Doppler (PD) ultrasound. Peripheral joint, enthesis, tendon, and bursa abnormalities were observed, characterizing abnormal PD. The affected patients and sites with abnormalities in various ages were compared among groups; PD signal grades for the abnormalities were also compared. Results. In the PsA group, significantly higher percentages of sites showing joint effusion/synovitis, enthesitis, and tenosynovitis in all age groups, and markedly higher rates of sites with bursitis were found in young and middle age groups, compared with the non-PsA and control groups (all p < 0.01). Meanwhile, the non-PsA group showed significantly higher rates of joint effusion/synovitis and enthesitis sites, and elevated PD signal grades of synovitis, enthesitis, and tenosynovitis in comparison with the control group, both in young and middle age groups (all p < 0.01). Conclusion. Patients with PsA have high percentages and PD signal grades of peripheral joint, tendon, enthesis, and bursa involvement. Young and middle-aged non-PsA patients have high synovitis and enthesitis percentages, and elevated PD signal grades of synovitis, enthesitis, and tenosynovitis.

Sonographic appearance of fluid in peripheral joints and bursae of healthy asymptomatic Chinese population

Background High frequency ultrasound is often used to measure the thickness of fluid in peripheral joints and bursae of healthy asymptomatic populations. Two major steps critical to this procedure are obtaining the detection rates and analyzing the relevant factors. Methods Healthy Chinese adult volunteers with no history of arthritis, past trauma or surgery and joint pain were enrolled in this study. Ultrasonography was performed on the bilateral shoulders, elbows, wrists, metacarpophalangeal joints (MCP) 1-5, proximal interphalangeal joints (PIP) 1-5, distal interphalangeal joints (DIP) 2-5, suprapatellar knees, ankles, metatarsophalangeal joints (MTP) 1-5, subacromial and subdeltoid bursae, deep infrapatellar bursae, retrocalcaneal bursae and long biceps tendons in B mode. Average size of fluid thickness and detection rate were calculated and correlated with demographic parameters. Mean + 1.64 SD was defined as the upper limit of the 95% reference range. Results One hundred and fifty-two volunteers (71 males and 81 females) with mean age of 48.0±14.1 years were enrolled. Both the highest detection rate and the thickest fluid were found in the suprapatellar knee (82.9%, 3.7±1.7 mm). There was no significant difference between the left and right side of the same structure in the detection rate and the fluid thickness. Females had a higher detection rate and fluid thickness than males in most examined structures, especially in the upper-limb joints. The greatest number of examined structures was found to be affected by age, and all of the correlations were positive (r from 0.118 to 0.510, P<0.05). Positive correlations were found in the long biceps tendon and MTP1 between detection rate and body mass index (BMI) (r=0.251 and 0.123, respectively, P<0.05), and in the long biceps tendon between effusion thickness and BMI (r=0.228, P<0.05). The upper limits of the 95% reference range for peripheral joints and bursae were determined. Conclusions Fluid in certain peripheral joints of healthy asymptomatic populations can be associated with gender, age or BMI. This study provided reference values for future comparisons with pathological conditions among Chinese populations.

Determination of Normal Skin Elasticity by Using Real-time Shear Wave Elastography: Normal Skin Elasticity on Real-time Shear Wave Elastography

To define the reference ranges of normal skin elasticity measurements associated with shear wave elastography (SWE) in healthy volunteers and analyze the factors that may affect SWE.

Ultrasound-Targeted Microbubble Destruction Delivery of Insulin-Like Growth Factor 1 cDNA and Transforming Growth Factor Beta Short Hairpin RNA Enhances Tendon Regeneration and Inhibits Scar Formation In Vivo

Ultrasound-targeted microbubble destruction (UTMD), which has been successfully used for the treatment of many diseases, offers a promising noninvasive approach for target-specific gene delivery. This study investigated the UTMD delivery of insulin-like growth factor 1 (IGF-1) cDNA and transforming growth factor beta (TGF-β) short hairpin RNA for Achilles tendon injury in rats. Briefly, 168 rats with an injured Achilles tendon were randomly divided into seven groups: (1) IGF-1 + UTMD, (2) TGF-β + UTMD, (3) IGF-1 + TGF-β + UTMD, (4) control, (5) IGF-1, (6) TGF-β, and (7) IGF-1 + TGF-β. At 2, 4, 8, and 12 weeks post treatment, six rats from each group were euthanized. IGF-1 expression and TGF-β expression were evaluated using an adhesion index score, pathological examination, quantitative real-time reverse transcription polymerase chain reaction, Western blotting, and biomechanical measurement. The lowest adhesion index score, the lightest inflammation, the highest 4,6-diamidino-2-phenylindole nuclear counter signals, the highest IGF-1 expression, and the lowest TGF-β expression were observed in group 3 (p < 0.05). Furthermore, higher expression of IGF-1 mRNA was observed in groups 1 and 3, while lower expression of TGF-β mRNA was observed in groups 2 and 3 (p < 0.05). The UTMD groups showed a higher transfection efficiency than the groups without UTMD. Downregulation of type III collagen and upregulation of type I collagen were observed in groups 1-3. Moreover, during weeks 4, 8, and 12, greater maximum load and tensile stress were observed in group 3 compared to the other groups (p < 0.05), while the highest tendon stiffness was observed in week 12 (p < 0.05). To conclude, the results suggest that UTMD delivery of IGF-1 and TGF-β offers a promising treatment approach for tendon injury in vivo.