Standard needle versus needleless injection modality: animal study on different fluids for submucosal elevation

Dynamic interaction of injected liquid jet with skin layer interfaces revealed by microsecond imaging of optically cleared ex vivo skin tissue model

BACKGROUND

Needle-free jet injection (NFJI) systems enable a controlled and targeted delivery of drugs into skin tissue. However, a scarce understanding of their underlying mechanisms has been a major deterrent to the development of an efficient system. Primarily, the lack of a suitable visualization technique that could capture the dynamics of the injected fluid-tissue interaction with a microsecond range temporal resolution has emerged as a main limitation. A conventional needle-free injection system may inject the fluids within a few milliseconds and may need a temporal resolution in the microsecond range for obtaining the required images. However, the presently available imaging techniques for skin tissue visualization fail to achieve these required spatial and temporal resolutions. Previous studies on injected fluid-tissue interaction dynamics were conducted using in vitro media with a stiffness similar to that of skin tissue. However, these media are poor substitutes for real skin tissue, and the need for an imaging technique having ex vivo or in vivo imaging capability has been echoed in the previous reports.

METHODS

A near-infrared imaging technique that utilizes the optical absorption and fluorescence emission of indocyanine green dye, coupled with a tissue clearing technique, was developed for visualizing a NFJI in an ex vivo porcine skin tissue.

RESULTS

The optimal imaging conditions obtained by considering the optical properties of the developed system and mechanical properties of the cleared ex vivo samples are presented. Crucial information on the dynamic interaction of the injected liquid jet with the ex vivo skin tissue layers and their interfaces could be obtained.

CONCLUSIONS

The reported technique can be instrumental for understanding the injection mechanism and for the development of an efficient transdermal NFJI system as well.

Expert consensus on the clinical application of high-frequency electrosurgery in digestive endoscopy (2020, Shanghai)

High-frequency electrosurgery has been widely applied in digestive endoscopy with constantly expanding indications. However, high-frequency electrosurgery may cause possible complications such as hemorrhage or perforation during or after the procedure, of which endoscopists must be cautious. Digestive endoscopists must have a firm grasp of the principles of high-frequency electrosurgery as well as its safety issues so as to improve the safety of its clinical application. To this end, experts in gastroenterology and hepatology, digestive endoscopy, surgery, nursing and other related fields were invited to draft a consensus on the clinical application of high-frequency electrosurgery in digestive endoscopy based on relevant domestic and international literatures and their experiences.

Replacing Needle Injection by a Novel Waterjet Technology Grants Improved Muscle Cell Delivery in Target Tissues

Current regimen to treat patients suffering from stress urinary incontinence often seems not to yield satisfactory improvement or may come with severe side effects. To overcome these hurdles, preclinical studies and clinical feasibility studies explored the potential of cell therapies successfully and raised high hopes for better outcome. However, other studies were rather disappointing. We therefore developed a novel cell injection technology to deliver viable cells in the urethral sphincter complex by waterjet instead of using injection needles. We hypothesized that the risk of tissue injury and loss of cells could be reduced by a needle-free injection technology. Muscle-derived cells were obtained from young male piglets and characterized. Upon expansion and fluorescent labeling, cells were injected into cadaveric tissue samples by either waterjet or injection needle. In other experiments, labeled cells were injected by waterjet in the urethra of living pigs and incubated for up to 7 days of follow-up. The analyses documented that the cells injected by waterjet in vitro were viable and proliferated well. Upon injection in live animals, cells appeared undamaged, showed defined cellular somata with distinct nuclei, and contained intact chromosomal DNA. Most importantly, by in vivo waterjet injections, a significantly wider cell distribution was observed when compared with needle injections (P < .05, n ≥ 12 samples). The success rates of waterjet cell application in living animals were significantly higher (≥95%, n = 24) when compared with needle injections, and the injection depth of cells in the urethra could be adapted to the need by adjusting waterjet pressures. We conclude that the novel waterjet technology injects viable muscle cells in tissues at distinct and predetermined depth depending on the injection pressure employed. After waterjet injection, loss of cells by full penetration or injury of the tissue targeted was reduced significantly in comparison with our previous studies employing needle injections.

Fluid cushion protects against thermal damage during argon plasma coagulation

Background

Thermal damage to the muscle layer during mucosal application of argon plasma coagulation (APC) may be avoided by creating a fluid cushion within the submucosal layer, but the minimum injection volume needed or the ideal injection fluid are yet to be established. We conducted a systematic ex vivo study with this aim.

Methods

All experiments were performed in an ex vivo porcine gastrointestinal tract model. Five different fluids (saline, Glyceol, Gelafundin, Voluven, and Eleview) of different volumes were injected into the submucosa of different parts of the gastrointestinal tract. APC was applied to the mucosa at different power settings. Immediately after APC treatment, the temperature was measured through a thermocouple placed inside the fluid cushion, just on top of the muscle layer. The minimum volume of fluid needed to protect the muscle layer from thermal damage was determined.

Results

There was no difference in the temperature measured among the different injection fluids at the surface of the muscle, in all the locations, at equal injection volumes and power settings. The minimum amounts of fluid needed to protect the muscle layer were 2 and 3 mL for power settings of 30-90 W and 90-120 W, respectively.

Conclusions

Normal saline and 4 commercially available submucosal injection fluids possess similar thermal protective effects. To reduce the likelihood of thermal damage to deeper layers when APC is applied, a minimum injection volume of 3 mL is recommended if less than 90 W power will be utilized over 3 sec.

Dispersion profile of a needle-free jet injection depends on the interfacial property of the medium

Injections into or through the skin are common drug or vaccine administration routes, which can be achieved with conventional needles, microneedles, or needle-free jet injections (NFJI). Understanding the transport mechanism of these injected fluids is critical for the development of effective drug administration devices. NFJI devices are distinct from traditional injection techniques by their route and time scale, which relies on a propelled microjet with sufficient energy to penetrate the skin surface and deliver the drug into the targeted region. The injected fluid interacts with multiple skin tissue layers and interfaces, which implies that the corresponding injection profile is dependent on their mechanical properties. In this study, we address the lack of fundamental knowledge on the impact of these interfaces on the injection profiles of NFJI devices.

Novel Techniques to Improve Precise Cell Injection

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n > 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted.

Rapid and precise delivery of cells in the urethral sphincter complex by a novel needle-free waterjet technology

OBJECTIVES

To investigate the therapy of stress urinary incontinence in a preclinical setting cells were injected into the urethrae of minipigs; however, cells injected by William's needle were frequently misplaced or lost; thus, we investigated if needle-free cell injections using a novel waterjet technology facilitates precise injections in the urethral sphincter complex.

MATERIALS AND METHODS

Porcine adipose tissue-derived stromal cells (pADSCs) were isolated from boars, expanded, labelled, and injected in the sphincter of female pigs by waterjet employing two different protocols. After incubation for 15 min or 3 days, the urethrae of the pigs were examined. Injected cells were visualised by imaging and fluorescence microscopy of tissue sections. DNA of injected male cells was verified by polymerase chain reaction (PCR) of the sex-determining region (SRY) gene. Cell injections by William's needle served as controls.

RESULTS

The new waterjet technology delivered pADSCs faster and with better on-site precision than the needle injections. Bleeding during or after waterjet injection or other adverse effects, such as swelling or urinary retention, were not observed. Morphologically intact pADSCs were detected in the urethrae of all pigs treated by waterjet. SRY-PCR of chromosomal DNA and detection of recombinant green fluorescent protein verified the injection of viable cells. In contrast, three of four pigs injected by William's needle displayed no or misplaced cells.

CONCLUSION

Transurethral injection of viable pADSCs by waterjet is a simple, fast, precise, and yet gentle new technology. This is the first proof-of-principle concept study providing evidence that a waterjet injects intact cells exactly in the tissue targeted in a preclinical in vivo situation. To further explore the clinical potential of the waterjet technology longer follow-up, as well as incontinence models have to be studied.

A novel submucosal injection solution for endoscopic resection of large colorectal lesions: a randomized, double-blind trial

BACKGROUND AND AIMS

SIC-8000 (Eleview) is a new U.S. Food and Drug Administration (FDA)-approved solution for submucosal injection developed to provide a long-lasting cushion to facilitate endoscopic resection maneuvers. Our aim was to compare the efficacy and safety of SIC-8000 with those of saline solution, when performing EMR of large colorectal lesions.

METHODS

In a randomized double-blind trial, patients undergoing EMR for colorectal non-pedunculated lesions ≥20 mm were randomized in a 1:1 ratio between SIC-8000 and saline solution as control solution in 5 tertiary centers. Endoscopists and patients were blinded to the type of submucosal solution used. Total volume to complete EMR and per lesion size and time of resection were primary endpoints; the Sydney Resection Quotient (SRQ), as well as other EMR outcomes, and the rate of adverse events were secondary endpoints. A 30-day telephone follow-up was performed. An alpha level <0.05 was considered as statistically significant.

RESULTS

Of the 327 patients screened, 226 (mean age, 66 ± 10 years; males, 56%) were enrolled in the study and randomized between the 2 submucosal agents. Of these, 211 patients (mean size of the lesions 33 ± 13 mm; Paris class Is, 36%; proximal colon, 74%) were entered in the final analysis (SIC-8000, 102; saline solution, 109). EMR was complete in all cases. The total volume needed for EMR was significantly less in the SIC-8000 arm compared with saline group (16.1 ± 9.8 mL vs 31.6 ± 32.0 mL; P < .001). This corresponded to an average volume per lesion size of 0.5 ± 0.3 mL/mm and 0.9 ± 0.6 mL/mm with SIC-8000 and saline solution, respectively (P < .001). The mean time to completely resect the lesion tended to be lower with SIC-8000 than with saline solution (19.1 ± 16.8 minutes vs 29.7 ± 68.9 minutes; P = .1). The SRQ was significantly higher with SIC-8000 compared with saline solution (10.3 ± 8.1 vs 8.0 ± 5.7; P = .04) with a trend for a lower number of resected pieces (5.7 ± 6.0 vs 6.5 ± 5.04; P = .052) and a higher rate of en bloc resections (19/102, 18.6% vs 12/111, 11.0%; P = .1). The rate of adverse events was similar between the 2 arms (SIC-8000, 18.6%; saline solution, 17%), and none of the serious adverse events (SIC-8000, 8.8%; saline solution, 10.7%) were related to the study treatment.

CONCLUSIONS

In a double-blind, randomized clinical trial, a new FDA-approved agent for sub-mucosal injection appeared to be a more effective and equally safe submucosal agent for EMR injection than saline solution. (Clinical trial registration number: NCT02654418.).

Efficacy and safety of SIC-8000 (Eleview®) for submucosal injection for endoscopic mucosal resection and endoscopic submucosal dissection in an in vivo porcine model

BACKGROUND

Submucosal injection is generally required for both endoscopic-mucosal resection (EMR) and submucosal dissection (ESD). SIC-8000 (Eleview™) is a new FDA 510(k) cleared and CE marked liquid composition for submucosal injection, containing a biocompatible polymer as a cushioning agent.

AIMS

The aim of this randomized study was to compare Eleview with saline solution when performing upper- and lower-GI EMR/ESD in a porcine model.

METHODS

EMR/ESD procedures were performed in a total of 10 white domestic pigs comparing Eleview vs. NaCl 0.9% containing methylene blue at 0.001% (control solution) as submucosal solution to be injected. Animals were randomized between EMR (22 procedures) and ESD (22 procedures) and between upper- (8 animals) and lower-(2 animals) GI procedures. All procedures were performed aiming for a resection size of 1 cm × 1 cm for EMR and 2 cm × 2 cm for ESD. Volume of injected fluid, number of injections, time of resection, technical success, en-bloc resection, and adverse events were collected. Endoscopic surveillance was conducted each week for 4 weeks after the EMR/ESD, including biopsies on the margins of resection sites at week-1 of follow-up. After four weeks, pigs were sacrificed and necropsy performed.

RESULTS

Overall, 22 EMR and 22 ESD were performed in 10 live pigs. The average total volume needed for EMR and ESD was statistically significantly lower with Eleview as compared with control solution for both of the techniques (EMR: 5.6 ± 3.4 ml vs. 11.5 ± 6.7 ml; p = 0.02; ESD: 19.0 ± 10.0 ml vs. 36.3 ± 16.9 ml; p = 0.02). The rate of adverse events was statistically significantly lower in the Eleview than in the control group (2/26, 7.7% vs. 6/18, 33.3%; p = 0.03), but most of them were minor. No difference between Eleview and control solution was found in the rate of technical success (EMR: 11/13, 84.6% vs. 7/9, 77.8%; p = 0.7; ESD: 13/13, 100% vs. 9/9, 100%; p = 1), en-bloc resection (EMR: 6/13, 46.2% vs. NaCl: 5/9, 55.6%; p = 0.06; ESD: 12/13, 92.3% vs. 8/9, 88.9%; p = 0.8), and time of resection (EMR: 9.1 ± 7.75 min vs. 9.4 ± 9.6 min; p = NS; ESD: 38.4 ± 17.2 min vs. 40.2 ± 19.1 min; p = NS). At endoscopic follow up and necropsy, no difference in the process of healing of post-endoscopic ulcer and in the histological inflammation at the site of resection was shown between the two groups.

CONCLUSIONS

The new submucosal injection composition Eleview appeared to be an effective alternative to saline solution for submucosal injection for EMR/ESD, resulting in a substantial reduction of the volume administered to achieve an adequate lifting. No signs of adverse local or distant tissue reaction to Eleview were found at long-term follow up.