Carrier-free mRNA vaccine induces robust immunity against SARS-CoV-2 in mice and non-human primates without systemic reactogenicity

Carrier-free naked mRNA vaccines may reduce the reactogenicity associated with delivery carriers; however, their effectiveness against infectious diseases has been suboptimal. To boost efficacy, we targeted the skin layer rich in antigen-presenting cells (APCs) and utilized a jet injector. The jet injection efficiently introduced naked mRNA into skin cells, including APCs in mice. Further analyses indicated that APCs, after taking up antigen mRNA in the skin, migrated to the lymph nodes (LNs) for antigen presentation. Additionally, the jet injection provoked localized lymphocyte infiltration in the skin, serving as a physical adjuvant for vaccination. Without a delivery carrier, our approach confined mRNA distribution to the injection site, preventing systemic mRNA leakage and associated systemic proinflammatory reactions. In mouse vaccination, the naked mRNA jet injection elicited robust antigen-specific antibody production over 6 months, along with germinal center formation in LNs and the induction of both CD4- and CD8-positive T cells. By targeting the SARS-CoV-2 spike protein, this approach provided protection against viral challenge. Furthermore, our approach generated neutralizing antibodies against SARS-CoV-2 in non-human primates at levels comparable to those observed in mice. In conclusion, our approach offers a safe and effective option for mRNA vaccines targeting infectious diseases.

Needle-free electronically-controlled jet injector treatment with bleomycin and lidocaine is effective and well-tolerated in patients with recalcitrant keloids

OBJECTIVES

The treatment of recalcitrant keloids is challenging. Although intralesional bleomycin using conventional needle injectors (CNI) is effective, it has important drawbacks, such as the need for repetitive and painful injections. Therefore, we aimed to evaluate the effectiveness, tolerability and patient satisfaction of intralesional bleomycin with lidocaine administered with a needle-free electronically-controlled pneumatic jet-injector (EPI) in recalcitrant keloids.

METHODS

This retrospective study included patients with recalcitrant keloids who had received three intralesional EPI-assisted treatments with bleomycin and lidocaine. Effectiveness was assessed using the Patient and Observer Scar Assessment Scale (POSAS) at baseline and four to six weeks after the third treatment. Additionally, treatment related pain scores numeric rating scale, adverse effects, patient satisfaction and Global Aesthetic Improvement Scale (GAIS) were assessed.

RESULTS

Fifteen patients with a total of >148 recalcitrant keloids were included. The median total POSAS physician- and patient-scores were respectively 40 and 41 at baseline, and reduced with respectively 7 and 6-points at follow-up ( p < 0.001; p < 0.001). The median pain scores during EPI-assisted injections were significantly lower compared to CNI-assistant injections, (2.5 vs. 7.0, respectively ( p < 0.001)). Adverse effects were mild. Overall, patients were "satisfied" or "very satisfied" with the treatments (14/15, 93.3%). The GAIS was "very improved" in one patient, "improved" in nine patients and "unaltered" in four patients.

CONCLUSIONS

EPI-assisted treatment with bleomycin and lidocaine is an effective, well tolerated, patient-friendly alternative for CNI in patients with recalcitrant keloid scars. Randomized controlled trials are warranted to confirm our findings and improve the clinical management of recalcitrant keloids.

Investigating the use of local nerve blocks and general anaesthesia in reducing pain during and after disbudding procedure in goat kids

The aim of this study was to compare the pain responses (as measured by noise and movement) during administration of local anaesthetic and during and after disbudding in goat kids. Eighty, seven- to ten-day-old, Saanen goat kids from one farm were enrolled and randomly assigned to one of four different methods of pain relief. Twenty kids had local anaesthetic (LA) applied at two sites per horn bud (LA group), 20 kids had LA applied to the two locations using a jet injector (JI group) and 20 kids were given a general anaesthetic (GA) using a combination of 0.02 mg/kg medetomidine and 2 mg/kg ketamine followed by a horn bud block applied as per the LA group (GA group). The remaining 20 kids had no treatment other than meloxicam (control group). Although responses between goat kids and at different time periods were variable, in comparison to the control group, GA eliminated the responses associated with injection of lignocaine and the responses during the period of disbudding, and provided a reduction in head scratches and shakes across multiple time periods.

Enhancement of polyethylene glycol-cell fusion efficiency by novel application of transient pressure using a jet injector

Cell-cell fusion involves the fusion of somatic cells into a single hybrid cell. It is not only a physiological process but also an important cell engineering technology which can be applied to various fields, such as regenerative medicine, antibody engineering, genetic engineering, and cancer therapy. There are three major methods of cell fusion: electrical cell fusion, polyethylene glycol (PEG) cell fusion, and virus-mediated cell fusion. Although PEG cell fusion is the most economical approach and does not require expensive instrumentation, it has a poor fusion rate and induces a high rate of cell cytotoxicity. To improve the fusion rate of the PEG method, we combined it with the pyro-drive jet injector (PJI). PJI provides instant pressure instead of cell agitation to increase the probability of cell-to-cell contact and shorten the distance between cells in the process of cell fusion. Here, we report that this improved fusion method not only decreased cell cytotoxicity during the fusion process, but also increased fusion rate compared with the conventional PEG method. Furthermore, we tested the functionality of cells fused using the PJI-PEG method and found them to be comparable to those fused using the conventional PEG method in terms of their application for dendritic cell (DC)-tumor cell fusion vaccine production; in addition, the PJI-PEG method demonstrated excellent performance in hybridoma cell preparation. Taken together, our data indicate that this method improves cell fusion efficiency as compared to the PEG method and thus has the potential for use in various applications that require cell fusion technology.

Comparison of Three Anaesthetic Options to Reduce Acute Pain Response in Kid Goats

Three options for anesthetizing the skin around the horn bud of dairy goat kids were explored. Forty-five <10-day-old Saanen goat kids from were randomly split into five treatment groups (topical anesthetic cream (TA), vapocoolant spray (VS), local anesthetic applied by jet injector (JI), control - no treatment but painful stimulus applied (C), sham - no treatment and touching sites with a finger. The painful stimulus was multiple needle pricks on the skin around the horn bud. The outcome variables measured were heart rate movement, and vocalization during treatment application and administration of a painful stimulus around the horn bud. Heart rates were greater during application of a VS compared to TA.Neither the TA nor the VS appeared to have any effect on the response to the painful stimulus. Kids in the JI group had a 96% reduced odds of expressing a marked pain response in comparison to TA group and an 83% reduction in the odds of a high movement grade during a painful procedure in comparison to the combined results of the other three treatment groups.

Mechanism and clinical applications of needle-free injectors in dermatology: Literature review

BACKGROUND

Needle-free jet injectors are devices that deliver drugs using a high-speed jet without a needle. Recent studies have significantly increased our understanding of the mechanisms of needle-free jet injectors, and technical advancements have broadened the scope of application of the device.

AIMS

We aimed to provide an up-to-date review of previous literature regarding the mechanism of action and clinical applications of needle-free jet injectors in dermatology field.

METHODS

We conducted a PUBMED search for studies on needle-free jet injectors using the following parameters: "Pneumatic injector" OR "needleless injector" OR "needle-free injector" OR "jet injector." Among 191 results, 72 articles focusing on their mechanisms of action, cutaneous delivery patterns, and clinical applications in dermatology were selected for review.

RESULTS

Significant clinical evidence has been published confirming the potential of needle-free jet injectors in treating various dermatologic conditions. In particular, these devices have the potential to be used in various skin remodeling treatment, especially in skin rejuvenation procedures by injecting various esthetic materials.

CONCLUSION

As proven by accumulated experience, the applications of NFJIs are not restricted to vaccine or insulin delivery in dermatology field. However, this literature review shows that until now, there are no clinical guidelines that standardize the optimal parameters when using NFJIs on various clinical settings. Therefore, further studies should be performed in order to investigate the full potential of these devices in dermatology, to ensure safe and effective outcomes in clinical practice.

Stable Immune Response Induced by Intradermal DNA Vaccination by a Novel Needleless Pyro-Drive Jet Injector

DNA vaccination can be applied to the treatment of various infectious diseases and cancers; however, technical difficulties have hindered the development of an effective delivery method. The efficacy of a DNA vaccine depends on optimal antigen expression by the injected plasmid DNA. The pyro-drive jet injector (PJI) is a novel system that allows for adjustment of injection depth and may, thus, provide a targeted delivery approach for various therapeutic or preventative compounds. Herein, we investigated its potential for use in delivering DNA vaccines. This study evaluated the optimal ignition powder dosage, as well as its delivery effectiveness in both rat and mouse models, while comparing the results of the PJI with that of a needle syringe delivery system. We found that the PJI effectively delivered plasmid DNA to intradermal regions in both rats and mice. Further, it efficiently transfected plasmid DNA directly into the nuclei, resulting in higher protein expression than that achieved via needle syringe injection. Moreover, results from animal ovalbumin (OVA) antigen induction models revealed that animals receiving OVA expression plasmids (pOVA) via PJI exhibited dose-dependent (10 μg, 60 μg, and 120 μg) production of anti-OVA antibodies; while only low titers (< 1/100) of OVA antibodies were detected when 120 μg of pOVA was injected via needle syringe. Thus, PJI is an effective, novel method for delivery of plasmid DNA into epidermal and dermal cells suggesting its promise as a tool for DNA vaccination.

Intravenous versus Subcutaneous Midazolam Using Jet-injector in Pediatric Sedation; a Randomized Clinical Trial

INTRODUCTION

The quality of interventions in children is largely dependent on their control. Hence, this study compared the sedative effects of subcutaneous (SC) and intravenous (IV) Midazolam in pediatric sedation induction.

METHODS

This randomized clinical trial was conducted on children aged 1-6 years presenting to emergency departments of Shahid Sadoughi and Shahid Rahnemoon Hospitals, Yazd, Iran. Participants were randomly assigned to IV or SC midazolam using a jet injector and success rate, degree of sedation, and satisfaction of parents and physician were compared between groups.

RESULTS

60 cases with the mean age of 3.15±1.43 (1-6) years were randomly assigned to the SC (30 cases) or IV (30 cases) groups (56.7% female). SC and IV groups were similar regarding the mean age (p = 0.165) and sex (p = 0.121). Depth of sedation (p=0.900), control of child (p=0.711), in-charge physician's satisfaction (p=0.467), successful sedation and need for rescue dose (p=0.519) were not different between groups. IV midazolam group had a significantly shorter recovery time (about 10 minutes; p=0.040) and SC midazolam group had a significantly higher level of parent satisfaction (p=0.001).

CONCLUSION

The findings indicate no significant difference in depth of sedation, control of child, in-charge physician's satisfaction, successful sedation (reaching stage 1 of sedation or higher), and need for rescue dose of SC and IV midazolam. Parents' satisfaction was significantly greater with SC administration and IV injection had shorter recovery time.

Pharmacokinetic and Pharmacodynamic Variability of Insulin When Administered by Jet Injection

BACKGROUND

Jet injection has been shown to accelerate the absorption and action of rapid-acting insulin. In this study, we compared the variability of absorption characteristics between jet injection and conventional administration of the rapid-acting insulin analogue aspart.

METHODS

A total of 30 healthy volunteers were enrolled in this randomized controlled blinded parallel study. On two test days, they received insulin aspart (0.2 units/kg body weight), either by jet injection or conventional pen, followed by a 6-hour euglycemic glucose clamp. Plasma glucose and insulin levels and glucose infusion rates were measured every 5 to 10 minutes to calculate the variability in pharmacological endpoints.

RESULTS

Jet injection advanced the times until maximal insulin concentration (T-INS_max) and glucose infusion rate (T-GIR_max) by ~40% (both P < .01). The difference between the two test days for these endpoints did not differ between jet injection and conventional administration (T-INS_max: 7.3 ± 1.9 vs 22.3 ± 6.3 min, P = .074; T-GIR_max: 24.0 ± 3.5 vs 27.3 ± 6.6 min, P = .66). The corresponding intraindividual coefficients of variation for injection by jet or conventional pen were 15.3 ± 3.3 and 22.0 ± 4.6% ( P = .25, P_variance = .044) for T-INS_max and 34.5 ± 5.1 and 21.2 ± 4.6% for T-GIR_max ( P = .064, P_variance = .62). The variance in maximal insulin concentration was significantly less after conventional administration ( P = .039). The variance in total glucose-lowering effect and total insulin exposure did not differ ( P = .93 and P = .32) Conclusion: Using a jet injector for insulin administration was associated with slightly altered variability in pharmacokinetic endpoints, but with about similar variability in pharmacodynamic endpoints compared to conventional administration. Variability in these endpoints remains considerable, regardless of the method of insulin administration.

Parents' attitude toward multiple vaccinations at a single visit with alternative delivery methods

Last decades, the number of routine childhood vaccinations has increased considerably, which consequently has led to multiple vaccine injections per consultation. Implementation of additional vaccines will probably lead to more than 2 vaccine injections per consult, which might be a barrier for parents to vaccinate their child. A decrease in vaccination coverage, however, increases the risk of disease outbreaks. Less stressful alternative methods for vaccine delivery might lead to an increased acceptance of multiple childhood vaccinations by parents. The present questionnaire study was set up to explore the maximum number of vaccine injections per visit that is acceptable for parents, as well as to gauge parents’ attitude toward alternative needle-free methods for vaccine delivery. For this purpose, the parents’ opinion toward a jet injector, a patch, a microneedle system, and nasal spray device as methods for vaccine delivery was assessed. The majority of the 1154 participating parents indicated that 3 vaccine injections per visit was perceived as too much. Most participants had a positive attitude with respect to the jet injector and the patch as alternative vaccine delivery method, whereas the microneedle device and an intranasal spray device were not perceived as better than the conventional syringe by the parents. Parents indicated that both the jet injector and the patch might increase their acceptance of giving their children more than 2 vaccinations at the same time. This should encourage vaccine developers and manufacturers to put efforts in developing these delivery methods for their vaccines.

Particle based vaccine formulations for transcutaneous immunization

Vaccine formulations on the basis of nano- (NP) or microparticles (MP) can solve issues with stabilization, controlled release, and poor immunogenicity of antigens. Likewise transcutaneous immunization (TCI) promises superior immunogenicity as well as the advantages of needle-free application compared with conventional intramuscular injections. Thus the combination of both strategies seems to be a very valuable approach. However, until now TCI using particle based vaccine formulations has made no impact on medical practice. One of the main difficulties is that NPs and MPs cannot penetrate the skin to an extent that would allow the application of the required dose of antigen. This is due to the formidable stratum corneum (SC) barrier, the limited amount of antigen in the formulation and often an insufficient immunogenicity. A multitude of strategies are currently under investigation to overcome these issues. We highlight selected methods presenting a spectrum of solutions ranging from transfollicular delivery, to devices disrupting the SC barrier and the combination of particle based vaccines with adjuvants discussing their advantages and shortcomings. Some of these are currently at an experimental state while others are already in clinical testing. All methods have been shown to be capable of transcutaneous antigen delivery.