Induction of mast cell degranulation in skin by ultrasound

Ultrasound in paediatric surgery: A meta-analysis review of its influence on postoperative wound healing and infection rates

Ultrasound (US) has traditionally been recognised for its imaging capabilities, but its emerging role as a therapeutic modality in postoperative wound management, especially in paediatric care, has garnered significant attention. This meta-analysis aimed to evaluate the influence of US on postoperative wound healing and infection rates in paediatric patients. From an initial pool of 1236 articles, seven were deemed suitable for inclusion. Postoperative wound healing was assessed using the Redness, Edema, Ecchymosis, Discharge, and Approximation (REEDA) scale. Notably, there was a significant difference in wound healing patterns between the US-treated and control groups (I2  = 94%, standardized mean difference [SMD]: -4.60, 95% confidence intervals [CIs]: -6.32 to -2.88, p < 0.01), as illustrated in Figure 4. Additionally, a marked difference in wound infection rates was observed between the groups (I2  = 93%, SMD: -5.86, 95% CIs: -9.04 to -2.68, p < 0.01), as portrayed in Figure 5. The findings underscore the potential benefits of US in enhancing postoperative wound healing and reducing infection rates in paediatric surgical settings. However, the application of US should be judicious, considering the nuances of individual patient needs and clinical contexts.

Mast cell stabilization: new mechanism underlying the therapeutic effect of intense pulsed light on rosacea

BACKGROUND

Rosacea, a chronic inflammatory disorder of the facial skin, is effectively treated by intense pulsed light (IPL).

OBJECTIVE

To explore the potential molecular mechanism underlying the photobiomodulation effect of IPL for rosacea treatment.

METHODS

Skin samples from patients with rosacea were subjected to histological and immunohistological staining. Ten patients were followed up after IPL treatment using the VISIA^® skin analysis system, and the severity was assessed. In vivo, skin changes in mice with rosacea-like inflammation induced by intradermal injection of 320 μM LL-37 with or without IPL treatment were evaluated using L*a*b colorimetry as well as histological and immunological staining. In vitro, LL-37-stimulated mast cells (MCs) with or without IPL treatment were evaluated for protein expression of matrix metalloproteinase (MMP)-9, kallikrein-related peptidase 5 (KLK5), and cathelicidin using western blotting and qRT-PCR.

RESULTS

Profound infiltration of inflammatory cells and evident MC degranulation were found in rosacea skin lesions. The expression of rosacea-related biomarkers and inflammatory cytokines was higher in lesional areas than in non-lesional areas, as demonstrated via immunochemical staining. In all patients, rosacea severity reduced after IPL therapy. In vivo, IPL alleviated inflammation in mice with rosacea-like inflammation, as demonstrated by the significantly decreased MMP-9, KLK5, and cathelicidin expression and reduced percentage of degranulating MCs. In vitro, IPL decreased MMP-9, KLK5, and cathelicidin expression in P815 cells, reducing the release of inflammatory cytokines and inhibiting rosacea-like inflammatory reactions.

CONCLUSION

The photobiomodulation effect of IPL for rosacea treatment may inhibit MC degranulation and alleviate inflammatory reactions.

Time- and Dose-Dependent Effects of Pulsed Ultrasound on Dermal Repair in Diabetic Mice

Chronic wounds, including diabetic, leg and pressure ulcers, impose a significant health care burden worldwide. Some evidence indicates that ultrasound can enhance soft tissue repair. However, therapeutic responses vary among individuals, thereby limiting clinical translation. Here, effects of pulsed ultrasound on dermal wound healing were assessed using a murine model of chronic, diabetic wounds. An ultrasound exposure system was developed to provide daily ultrasound exposures to full-thickness, excisional wounds in genetically diabetic mice. Wounds were exposed to 1 MHz ultrasound (2 ms pulse, 100 Hz pulse repetition frequency, 0-0.4 MPa) for 2 or 3 wk. Granulation tissue thickness and wound re-epithelialization increased as a function of increasing ultrasound pressure amplitude. At 2 wk after injury, significant increases in granulation tissue thickness and epithelial ingrowth were observed in response to 1 MHz pulsed ultrasound at 0.4 MPa. Wounds exposed to 0.4 MPa ultrasound for 3 wk were characterized by collagen-dense, revascularized granulation tissue with a fully restored, mature epithelium. Of note, only half of wounds exposed to 0.4 MPa ultrasound showed significant granulation tissue deposition after 2 wk of treatment. Thus, the db⁺/db⁺ mouse model may help to identify biological variables that influence individual responses to pulsed ultrasound and accelerate clinical translation.

Functional MRI Investigation of Ultrasound Stimulation at ST 36

Background

Clinical and experimental data suggest that ultrasound stimulation (US) at acupoints can produce similar effective treatment compared to manual acupuncture (MA). Although the brain activation to MA at acupoints is investigated by numerous studies, the brain activation to US at acupoints remains unclear.

Methods

In the present work, we employed task state functional magnetic resonance imaging (fMRI) to explore the human brain's activation to US and MA at ST 36 (Zusanli) which is one of the most commonly used acupoints in acupuncture-related studies. 16 healthy subjects underwent US and MA procedures in an interval of more than one week. On-off block design stimulation was used for the recording of fMRI-related brain patterns.

Results

Both US and MA at ST 36 produced activations in somatosensory and limbic/paralimbic regions (postcentral gyrus, insula, middle prefrontal cortex, and anterior cingulate cortex). Only US at ST 36 produced a significant signal increase in the inferior parietal lobule and decrease in the posterior cingulate cortex, whereas MA at ST 36 produced a significant signal increase in the lentiform nucleus and cerebellum.

Conclusions

Our results indicate that US may be a possible noninvasive alternative method to MA due to its similar activation patterns.

Botulinum toxin blocks mast cells and prevents rosacea like inflammation

BACKGROUND

Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.

OBJECTIVES

To investigate the molecular mechanism by which botulinum toxin improves rosacea lesions.

METHODS

Primary human and murine mast cells were pretreated with onabotulinum toxin A or B or control. Mast cell degranulation was evaluated by β-hexosaminidase activity. Expression of botulinum toxin receptor Sv2 was measured by qPCR. The presence of SNAP-25 and VAMP2 was established by immunofluorescence. In vivo rosacea model was established by intradermally injecting LL-37 with or without onabotulinum toxin A pretreatment. Mast cell degranulation was assessed in vivo by histologic counts. Rosacea biomarkers were analyzed by qPCR of mouse skin sections.

RESULTS

Onabotulinum toxin A and B inhibited compound 48/80-induced degranulation of both human and murine mast cells. Expression of Sv2 was established in mouse mast cells. Onabotulinum toxin A and B increased cleaved SNAP-25 and decreased VAMP2 staining in mast cells respectively. In mice, injection of onabotulinum toxin A significantly reduced LL-37-induced skin erythema, mast cell degranulation, and mRNA expression of rosacea biomarkers.

CONCLUSIONS

These findings suggest that onabotulinum toxin reduces rosacea-associated skin inflammation by directly inhibiting mast cell degranulation. Periodic applications of onabotulinum toxin may be an effective therapy for refractory rosacea and deserves further study.

The effect of 22.5 kHz low-frequency contact ultrasound debridement (LFCUD) on lower extremity wound healing for a vascular surgery population: A randomised controlled trial

The aim of this study was to compare changes in wound size and appearance and health complication rates in patients with vasculopathy and lower-extremity wounds treated with or without low-frequency contact ultrasound debridement (LFCUD) This study was a randomised controlled trial. The study was conducted in a vascular surgery service, including outpatient wound clinic and inpatient ward, in a tertiary care academic centre. In total, 70 patients with vasculopathy and lower-extremity wounds of mixed aetiology were enrolled in the trial; 68 completed the study. Patients were randomised to receive LFCUD plus usual care (n = 33) or usual care (n = 37) at 4 weekly visits, and were followed thereafter for up to 12 wk. The main outcome measures included closed wounds, change in wound surface area (WSA), and wound appearance by the revised Photographic Wound Assessment Tool (revPWAT). After 4 weekly LFCUD treatments, patients in the LFCUD group had significantly better wound appearance (total revPWAT score) compared with the control group treated only with usual care (P = <0.05). LFCUD-treated wounds also had a significant reduction in WSA over 4 wk that was not found in the UC group. LFCUD treatment was also associated with a greater number of healed wounds, odds ratio 5.00 (95% CI 1.24-20.25), and fewer instances of wound deterioration. Weekly LFCUD applications to patients with significant vasculopathy resulted in superior healing outcomes when compared with current usual wound care practice.

Substance P signaling controls mast cell activation, degranulation, and nociceptive sensitization in a rat fracture model of complex regional pain syndrome

BACKGROUND

Patients with complex regional pain syndrome have increased tryptase in the skin of the affected extremity indicating mast cell (MC) accumulation and degranulation, processes known to be mediated by substance P (SP). The dysregulation of SP release from primary afferent neurons is characteristic of complex regional pain syndrome. The authors hypothesized that SP acting through the neurokinin-1 receptor results in mast cell accumulation, degranulation, and nociceptive sensitization in a rat model of complex regional pain syndrome.

METHODS

Groups of 6-10 rats underwent tibia fracture and hind limb casting for 4 weeks, and the hind paw skin was harvested for histologic and immunohistochemical analysis. The effects of a selective neurokinin-1 receptor antagonist (LY303870) and of direct SP intraplantar injection were measured. Dermal MC degranulation induced by sciatic nerve stimulation and the effects of LY303870 on this process were investigated. Finally, the antinociceptive effects of acute and chronic treatment with a MC degranulator (48/80) were tested.

RESULTS

The authors observed that fracture caused MC accumulation, activation, and degranulation, which were inhibited by LY303870; the percentage of MCs in close proximity to peptidergic nerve fibers increased after fracture; electrical stimulation caused MC activation and degranulation, which was blocked by LY303870; intraplantar SP-induced MC degranulation and acute administration of 48/80 caused MC degranulation and enhanced postfracture nociception, but MC-depleted animals showed less sensitization.

CONCLUSIONS

These results indicate that facilitated peptidergic neuron-MC signaling after fracture can cause MC accumulation, activation, and degranulation in the injured limb, resulting in nociceptive sensitization.

Effect of low-level treatment with an 80-Hz pulsed infrared diode laser on mast-cell numbers and degranulation in a rat model of third-degree burn

BACKGROUND DATA

Low-level laser therapy (LLLT) has been reported to be capable of changing mast cell numbers and degranulation in experimental burns in rats.

OBJECTIVE

We conducted a study of the influence of LLLT on mast cells in a rat model of third-degree burn.

METHODS

In this study we divided 48 rats equally into two groups of 24 rats each. Third-degree burns were inflicted at three different locations on each rat in each group. The first burn site on rats in group I was treated with 890-nm pulsed laser, 75W peak, 80 Hz, 180 ns, average power 1mW, illuminated area 1 cm(2), 1 mW/cm(2), 856 sec, 0.924 J/cm(2). The second burn site on both groups of rats was treated with 0.2% nitrofurazone cream. Mast cell numbers and degranulation at each burn site on each group of rats were then assessed at 4, 8, 13, and 20 days after the infliction of burns.

RESULTS

Analysis of variance on day 4 showed that the total numbers of mast cells were significantly lower at the laser-treated burn sites than at other burn sites on both groups of rats. On day 8 the total numbers of mast cells were again significantly lower at the laser-treated burn sites than at other burn sites, and on day 13, the numbers of both types 1 and 2 mast cells were significantly lower at the laser-treated burn sites than at other burn sites.

CONCLUSIONS

We conclude that LLLT can significantly decrease total numbers of mast cells during the proliferation and remodeling phases of healing in a rat model of third-degree burn.

Indirect low-intensity ultrasonic stimulation for tissue engineering

Low-intensity ultrasound (LIUS) treatment has been shown to increase mass transport, which could benefit tissue grafts during the immediate postimplant period, when blood supply to the implanted tissue is suboptimal. In this in vitro study, we investigated effects of LIUS stimulation on dye diffusion, proliferation, metabolism, and tropomyosin expression of muscle cells (C2C12) and on tissue viability and gene expression of human adipose tissue organoids. We found that LIUS increased dye diffusion within adjacent tissue culture wells and caused anisotropic diffusion patterns. This effect was confirmed by a hydrophone measurement resulting in acoustic pressure 150–341 Pa in wells. Cellular studies showed that LIUS significantly increased proliferation, metabolic activity, and expression of tropomyosin. Adipose tissue treated with LIUS showed significantly increased metabolic activity and the cells had similar morphology to normal unilocular adipocytes. Gene analysis showed that tumor necrosis factor-alpha expression (a marker for tissue damage) was significantly lower for stimulated organoids than for control groups. Our data suggests that LIUS could be a useful modality for improving graft survival in vivo.

Therapeutic opportunities in biological responses of ultrasound

The therapeutic benefits of several existing ultrasound-based therapies such as facilitated drug delivery, tumor ablation and thrombolysis derive largely from physical or mechanical effects. In contrast, ultrasound can also trigger various time-dependent biochemical responses in the exposed biological milieu. Several biological responses to ultrasound exposure have been previously described in the literature but only a handful of these provide therapeutic opportunities. These include the use of ultrasound for healing of soft tissues and bones, the use of ultrasound for inducing non-necrotic tumor atrophy as well as for potentiation of chemotherapeutic drugs, activation of the immune system, angiogenesis and suppression of phagocytosis. A review of these therapeutic opportunities is presented with particular emphasis on their mechanisms. Overall, this review presents the increasing importance of ultrasound's role as a biological sensitizer enabling novel therapeutic strategies.

Short-duration-focused ultrasound stimulation of Hsp70 expression in vivo

The development of transgenic reporter mice and advances in in vivo optical imaging have created unique opportunities to assess and analyze biological responses to thermal therapy directly in living tissues. Reporter mice incorporating the regulatory regions from the genes encoding the 70 kDa heat-shock proteins (Hsp70) and firefly luciferase (luc) as reporter genes can be used to non-invasively reveal gene activation in living tissues in response to thermal stress. High-intensity-focused ultrasound (HIFU) can deliver measured doses of acoustic energy to highly localized regions of tissue at intensities that are sufficient to stimulate Hsp70 expression. We report activation of Hsp70-luc expression using 1 s duration HIFU heating to stimulate gene expression in the skin of the transgenic reporter mouse. Hsp70 expression was tracked for 96 h following the application of 1.5 MHz continuous-wave ultrasound with spatial peak intensities ranging from 53 W cm(-2) up to 352 W cm(-2). The results indicated that peak Hsp70 expression is observed 6-48 h post-heating, with significant activity remaining at 96 h. Exposure durations were simulated using a finite-element model, and the predicted temperatures were found to be consistent with the observed Hsp70 expression patterns. Histological evaluation revealed that the thermal damage starts at the stratum corneum and extends deeper with increasing intensity. These results indicated that short-duration HIFU may be useful for inducing heat-shock expression, and that the period between treatments needs to be greater than 96 h due to the protective properties of Hsp70.

A Comparison of Intramuscular Temperatures during 10-Minute 1.0-MHz Ultrasound Treatments at Different Intensities

Context:

Research on therapeutic ultrasound has not focused on the duration needed to cause thermal change with various ultrasound intensities.

Objective:

To analyze triceps surae intramuscular temperature using 4 intensity levels after a 10-min 1-MHz continuous ultrasound treatment at a depth of 4 cm.

Design:

1 × 4 repeated measures. Independent variable: intensity of 4 levels—0.5, 1.0, 1.5, and 2.0 W/cm2. Dependent variable: peak intramuscular temperature.

Setting:

Research laboratory.

Participants:

19 volunteers with no lower leg pathologies.

Intervention:

Treatment order was balanced via Latin square and performed 24 hr apart.

Main Outcome Measures:

Peak intramuscular temperatures.

Results:

The only significant difference detected was that the mean temperature after the 1.0-W/cm2 treatment (37.3 °C) was greater than that at 2.0-W/cm2 intensity (36.1 °C). No treatment reached the desired 4° increase needed for therapeutic efficacy.

Conclusions:

Treatments at 1.0 W/cm2 increased tissue temperatures more than those at 2.0 W/cm2.

Effects of ultrasound delivered through a mist of saline to wounds in mice with diabetes mellitus

OBJECTIVE

To examine the effects of ultrasound administered through a fine mist of saline on surgically placed full-thickness excisional wounds in mice with experimental diabetes mellitus.

METHOD

Fifty male CD-I mice received alloxan monohydrate (100 mg/kg), a drug known to induce diabetes mellitus. The animals received five ultrasound (n = 27) or sham (n = 23) treatments for 1.5 minutes, on alternate days, for 10 days, and were then sacrificed. Following sacrifice, each animal's wound was excised and the tissues prepared for qualitative and quantitative histological analysis.

RESULTS

No difference in wound-surface area was found between the groups after the treatment period. However, blinded assessment of tissue sections revealed significantly increased deposition of collagen and blood vessels in the granulation tissue of animals treated with ultrasound compared with those that received sham therapy.

CONCLUSION

Ultrasound delivered through a fine mist of saline significantly altered the composition of newly formed granulation tissue in animals with experimental diabetes mellitus. Further research needs to be completed to determine other effects of this novel ultrasound therapy and to examine its clinical effectiveness.

Pre-exposure effects of 1 and 3 MHz therapeutic ultrasound on ConA activated spleenocytes

This study was performed to evaluate the pre-exposure effects of ultrasound (1 MHz or 3 MHz) on ConA activated spleenocyte proliferation and cytokine production. Cells were treated for 10 min at various intensities, rested for 1h and stimulated with the T cell activator ConA. The cells were then analyzed for the effects of non-thermal ultrasound on cell growth and the presence of IL-2, IL-4 and IFN-g. The data show that pre-exposure of spleenocytes had no significant effects on the proliferation of ConA activated spleenocytes at either 1 or 3 MHz (10 min at 0.1 or 0.5 W/cm(2)). Significant increases in IL-2 were observed in both 1 and 3 MHz pre-treated and ConA activated spleenocytes. Cells pre-treated with 1 MHz and stimulated with ConA showed a significant increase in IL-4 and IFN-g. Conversely, cells pre-treated with 3 MHz and stimulated with ConA show a significant decrease in IL-4 and IFN-g. Interleuken-4 is known to increase the growth of mast cells, inhibit macrophage activation and increases the activity of the T cell subpopulation, T(H2). Interferon-gamma is known to stimulate production of collagen in fibroblasts, enhance debridement activity of macrophage and inhibit activity of the T cell subpopulation, T(H2).

The role of electrotherapy in contemporary physiotherapy practice

Although electrotherapy has a well established role within physiotherapy practice, the current concepts that influence its application vary considerably from those proposed historically. It is argued that there is a place for electrophysical modalities in contemporary practice, and several basic principles are considered together with more specific information regarding two modalities namely, ultrasound and interferential therapy. Electrophysical agents are utilised to bring about physiological effects, and it is these changes which bring about the therapeutic benefit rather than the modality itself. Clinical decision protocols employing the available evidence should enable the most appropriate modality to be employed for a particular patient. Indiscriminate use of electrotherapy is unlikely to yield significant benefit, however used at the right time, it has the potential to achieve beneficial effect. The patient management programme which combines manual therapy, exercise therapy and electrotherapy, based on current evidence, should enable the most efficacious management of a patients' dysfunction. This paper aims to consider some of the current concepts in electrotherapy and to relate this to both general and specific treatments.

Effects of pulsed ultrasound on embryonic development: an in vitro study

Whole-embryo culture was used as the model system to study the effects of pulsed ultrasound on embryonic development. Rat embryos (9.5 days old) were exposed to a wide range of ultrasound levels at ultrasound frequencies between 1-4 MHz for 30 min in vitro. After 48 h in culture, absolute control, sham and treatment embryos were assessed for viability, morphology, growth and development. At an ambient temperature of 37 degrees C, no significant effects were observed for spatial peak temporal average intensities below 4 W/cm2 or peak negative pressures below 1.9 MPa. At higher acoustic levels, there was a significant increase in the number of nonviable embryos and the number of morphological abnormalities in viable embryos increased. Abnormal cephalocaudal flexion and abnormal head development were the most common gross morphological abnormalities. Both thermal and nonthermal bioeffect mechanisms are involved.

Assessment of thermal damage in precooled CO2 laser wounds using biological markers

Precooling of the tissues was investigated as a possible means of reducing the thermal damage during CO2 laser surgery of the oral mucosa. Standard wounds 5 mm long were created with the CO2 laser, with and without precooling, or the scalpel on the dorsum of tongues. Tissue damage was evaluated by studying changes in mast cells and in the activity of lactate (LDH) and succinate (SDH) dehydrogenase. Cooled unoperated tongues acted as controls. The area of thermal damage, indicated by loss of SDH activity, was significantly smaller in precooled tissues (p < 0.001). Although a similar pattern was detected using LDH, the difference was not significant. At both 0 and 6 h normal mast cell numbers were significantly different between groups (p < 0.02). Furthermore, at 0 time, there were significant differences in the numbers of degranulated mast cells between surgical treatment groups (p = 0.001), although not at 6 h. Total numbers of mast cells (normal and degranulated) did not differ between treatment groups or between 0 and 6 h sampling times. Positive significant correlations were observed between the cross-sectional areas and widths of non-reactive succinate and lactate dehydrogenase and the number of degranulated mast cells around the laser wounds. Analysis of the data demonstrated that (i) uncooled laser wounds but not precooled laser wounds were associated significantly with greater levels of immediate mast cell degranulation than scalpel wounds (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)