Botulinum toxin A and B raise blood flow and increase survival of critically ischemic skin flaps

Effect of botulinum toxin-A injection applied to the mentalis muscle on free gingival graft operation: A retrospective study

OBJECTIVE

The purpose of this retrospective study was to investigate the effects of Botulinum Toxin-A (BTX-A) injection into the mentalis muscle on the free gingival graft (FGG).

MATERIALS AND METHODS

Forty patients with keratinized gingiva insufficiency and Cairo's RT 2 gingival recession (formerly classified as Miller class III) in their mandibular central incisors were randomly divided into two groups: FGG and FGG + BTX. Plaque index (PI), gingival index (GI), probing pocket depth (PPD), keratinized gingiva width (KGW), attached gingiva width (AGW), clinical attachment level (CAL), gingival thickness (GT), gingival recession amount (GRA), gingival recession width (GRW), and root closure percentage (RCP%) parameters were measured at baseline and at first, third, and sixth months after the operation.

RESULTS

There was no difference in PI, GI, and PPD levels in both groups (p > 0.05). While the change in GT and RCP% levels were found to be statistically significantly higher at FGG + BTX group than FGG group, the change in GRW and CAL levels were statistically significantly lower (p < 0.05).

CONCLUSION

The findings of this study indicate that BTX-A injection applied to the mentalis muscle after FGG operation may have positive effects in terms of KGW, AGW, GT, RCP%, GRW, and CAL parameters.

CLINICAL SIGNIFICANCE

As a result of the fact that BTX-A injection into the mentalis muscle contributed to the nutrition and immobility of FGG, positive developments were obtained in terms of clinical periodontal parameters. BTX-A injection into the mentalis muscle may be an alternative method that increases the success rate of Cairo's RT 2 gingival recession.

Botulinum toxin type A in multimodal management of age-related macular degeneration and related diseases

Age related macular degeneration (AMD) is the major cause of visual loss in the aging population in the Western world. In past decade, intra ocular injections of anti-vascular endothelial growth factor (anti-VEGF) pharmaceuticals have revolutionized therapy for exudative (edematous-wet) AMD and become standard practice for the near term. However repeated intra-ocular injections are required for years and long terms results have been limited. The pathogenesis of this condition is multifactorial involving genetic, ischemic, inflammatory factors leading to neovascularization, edema and retinal pigment epithelial scaring resulting in photoreceptor destruction. Based on coincidental observation in reduction in AMD related macular edema on ocular coherence tomography (OCT) in a BoNT A treated patient with facial movement disease, BoNT-A at conventional doses targeting the para orbital area was added to therapeutic regiment in a small number of patients with exudative macular degeneration or related diseases. Measurements of edema and choriocapillaris using Spectral Doman (OCT) and Ocular Coherence Angiography (OCT-A) and Snellen visual acuity were made over the evaluation period. 15 eyes in 14 patients averaged 361 μm central sub foveal edema (CSFT) pre injection and average of 266 μm (CSFT) post injection over an average of 21 months and 5.7 cycles using BoNT A alone at conventional doses (n = 86 post injection measurements, paired t-test p < 0.001 two tailed). Visions at baseline in patients with 20/40 or worse averaged 20/100- pre injection improved to an average of 20/40- in the post injection period (n = 49 measurements p < 0.002 paired t-test). The previous data was added to a group of 12 more severely afflicted patients receiving anti VEGF (aflibercept or bevacizumab) (total 27 patients). With this 27-patient group, patients were followed for an average of 20 months and receiving average of 6 cycles at conventional doses. Improvement in exudative edema and vision were noted with pre injection baseline CSFT average 399.5, post injection average 267, n = 303 post measurement, independent t-test P < 0.0001.). Snellen vision 20/128 baseline average improved to average of 20/60- during post injection period (n = 157 post injection measurements, p < 0.0001 paired t-test to baseline). No substantial adverse effects were noted. Cyclic effects were noted corresponding to duration of action of BoNT-A on a number of patients. The above data is preliminary and is skewed toward early leakage for all conditions. BoNT A may have a role in the treatment of aged related macular degeneration. Controlled studies are needed with careful staging and baseline stratifications for multi-modal management paradigms. The findings are discussed relative to known botulinum toxin type A pharmacology and AMD pathogenesis.

Determination of Flap Survival Isolated From Wound Bed Vasculature Using a Murine Axial Flap Model

Background: Axial pattern flaps are a common reconstructive option following resection of soft tissue malignancies. We determine the early dependence of an axial flap on wound bed vasculature by isolating the underlying wound bed and depriving contact with the overlying flap. Materials and Methods: Mice were divided into 5 groups: No silicone (n = 7), silicone in the proximal 50% of the wound bed (n = 8), silicone in the distal 50% of the wound bed (n = 5), silicone over the full length of the wound bed with pedicle preservation (n = 5), and silicone over the full length of the wound bed with pedicle sacrifice (n = 5). The pedicle was the lateral thoracic artery. Daily photographs were taken, and the percent of viable flap was determined using ImageJ© software (public domain JAVA image processing program, National Institute of Health, Bethesda, MA). Percent flap viability for each group was compared to the no silicone group, which acted as the reference. Results: Mean differences in percent flap necrotic area (with 95% confidence interval) compared to the no silicone group were -0.15% (-15.09 to 14.09), 2.07% (-5.26 to 9.39), 2.98% (-10.98 to 16.94), and 14.21% (0.48 to 27.94) for the full-length silicone with preserved pedicle, proximal silicone, distal silicone, and full-length silicone with sacrificed pedicle groups, respectively. The full-length silicone with sacrificed pedicle group had a significant difference in flap viability (P = .045) compared to the no silicone group. Conclusion: We investigate the role of the wound bed vasculature in a murine axial flap model and demonstrate that the wound bed vasculature is not essential for early distal flap survival.

Botulinum Toxin A and B Improve Perfusion, Increase Flap Survival, Cause Vasodilation, and Prevent Thrombosis: A Systematic Review and Meta-analysis of Controlled Animal Studies

BACKGROUND

A systematic review and meta-analysis of case-control animal model studies will help clarify the vascular effects of botulinum toxin (BTX).

METHODS

Preferred Reporting Items of Systematic reviews and Meta-Analyses guidelines were used to identify all animal case-control studies published before September 13, 2020, evaluating the vascular effects of BTX. Primary parameters included the following: perfusion, flap survival, arterial and venous dilation, and arterial and venous thrombosis.

RESULTS

Thirty-six studies with 1032 animals met the systematic review inclusion criteria. Twenty-nine studies had quantifiable data for statistical analysis. Statistically significant increases in perfusion with BTX over saline were detected within 1 day and sustained up to 8 weeks. The following represent weighted mean data from the meta-analysis. The administration of BTX has a 26% increase in both random pattern and pedicled flap survival area over controls. Botulinum toxin causes vasodilation. Botulinum toxin increases vessel diameter in arteries by 40% and in veins by 46% compared with saline controls. The administration of BTX reduces thrombosis by 85% in arteries and by 79% in veins compared with saline controls. Vascular effects were consistent across both BTX-A and BTX-B serotypes, multiple animal species, and various doses. No clear relationships between vascular effects and BTX pretreatment time were identified.

CONCLUSIONS

Perivascular BTX administration intraoperatively or as a chemical delay pretreatment several days before surgery in multiple animal species and models shows multiple changes to the vascular system. Extrapolation of lessons learned from this systematic review and meta-analysis of animal models could expand research and clinical use of BTX in human vascular disease and surgery.

Experimental study of the effects of nitroglycerin, botulinum toxin A, and clopidogrel on bipedicled superficial inferior epigastric artery flap survival

Beneficial effects could be achieved by various agents such as nitroglycerin, botulinum toxin A (BoTA), and clopidogrel to improve skin flap ischaemia and venous congestion injuries. Eighty rats were subjected to either arterial ischaemia or venous congestion and applied to a bipedicled U-shaped superficial inferior epigastric artery (SIEA) flap with the administration of nitroglycerin, BoTA, or clopidogrel treatments. After 7 days, all rats were sacrificed for flap evaluation. Necrotic area percentage was significantly minimized in flaps treated with clopidogrel (24.49%) versus the ischemic flaps (34.78%); while nitroglycerin (19.22%) versus flaps with venous congestion (43.26%). With ischemia, light and electron microscopic assessments revealed that nitroglycerin produced degeneration of keratinocytes and disorganization of collagen fibers. At the same time, with clopidogrel administration, there was an improvement in the integrity of these structures. With venous congestion, nitroglycerin and BoTA treatments mitigated the epidermal and dermal injury; and clopidogrel caused coagulative necrosis. There was a significant increase in tissue gene expression and serum levels of vascular endothelial growth factor (VEGF) in ischemic flaps with BoTA and clopidogrel, nitroglycerin, and BoTA clopidogrel in flaps with venous congestion. With the 3 treatment agents, gene expression levels of tumor necrosis factor-α (TNF-α) were up-regulated in the flaps with ischemia and venous congestion. With all treatment modalities, its serum levels were significantly increased in flaps with venous congestion and significantly decreased in ischemic flaps. Our analyses suggest that the best treatment option for ischemic flaps is clopidogrel, while for flaps with venous congestion are nitroglycerin and BoTA.

Botulinum Toxin Type A for the Treatment of Skin Ulcers: A Review Article

The normal biological wound healing process consists of three precisely and highly programmed phases that require optimal conditions including internal and external factors. Any negative factors that disrupt the sequence or time frame of the healing mechanism can result in a non-healing wound or chronic ulcers. Botulinum neurotoxin A (BoNT-A) which is generally known as anti-contraction of muscles has been reported as a successful treatment in various types of chronic ulcers. The aim of this study is to review the outcome of treatment with BoNT-A for chronic skin ulcers. The results demonstrated some positive effects of BoNT-A on chronic ulcers. Ischemic ulcers secondary to Raynaud’s phenomenon seem to be the most promising type of ulcers that have benefited from BoNT-A. The rationale behind using BoNT-A to fasten the wound healing process is also discussed. Further clinical trial studies should be conducted to affirm the efficacy of wound healing using BoNT-A administration.

Single injection of very mild dose botulinum toxin in the vastus lateralis improves testicular spermatogenesis and sperm motility in ageing experimental mice

Background

Botulinum toxin (BoNT) is a widely used therapeutic agent that blocks the excessive release of acetylcholine at the neuromuscular junction. Previously, repeated intracremasteric injections and slight overdose of BoNT have been reported to induce adverse effects in the testicular parameter of experimental rodents. However, a mild dose of BoNT is highly beneficial against skin ageing, neuromuscular deficits, overactive urinary bladder problems, testicular pain and erectile dysfunctions. Considering the facts, the possible therapeutic benefits of BoNT on the testis might be achieved at a very minimal dosage and via a distal route of action. Therefore, we revisited the effect of BoNT, but with a trace amount injected into the vastus lateralis of the thigh muscle, and analyzed histological parameters of the testis, levels of key antioxidants and sperm parameters in ageing experimental mice.

Results

Experimental animals injected with 1 U/kg bodyweight of BoNT showed enhanced spermatogenesis in association with increased activities of key antioxidants in the testis, leading to enhanced amount of the total sperm count and progressive motility.

Conclusions

This study signifies that a mild intramuscular dose of BoNT can be considered as a potent treatment strategy to manage and prevent male infertility.

Intramuscular Neural Arborization of the Latissimus Dorsi Muscle: Application of Botulinum Neurotoxin Injection in Flap Reconstruction

Postoperative pain after breast reconstruction surgery with the latissimus dorsi flap is a common occurrence. Botulinum neurotoxin (BoNT) injection during surgery is effective in reducing postoperative pain. This study aimed to determine the most appropriate locations for BoNT injection. A modified Sihler’s method was performed on the latissimus dorsi muscles in 16 specimens. Intramuscular nerve arborization was noted under the landmark of the medial side surgical neck of the humerus to the line crossing the spinous process of T5 and the middle of the iliac crest. The latissimus dorsi muscles were divided into medial, middle, and lateral segments with 10 transverse divisions to give 10 sections (each 10%). Intramuscular nerve arborization of the latissimus dorsi muscle was the largest from the medial and lateral part of the muscle ranging from 40 to 60%, middle part from 30 to 60% and medial, middle and lateral part from 70 to 90%. The nerve entry points were at the medial and lateral part with 20–40% regarding the medial side of surgical neck of the humerus to the line crossing spinous process of T5 to the middle of iliac crest. These outcomes propose that an injection of BoNT into the latissimus dorsi muscles should be administered into specific zones.

Effects of Botulinum Toxin A on the Blood Flow in Expanded Rat Skin

Background Poor blood supply can easily lead to expander extrusion and necrosis at the distal expanded flap. Botulinum toxin A (BTX-A) has been previously found to improve pedicled flap blood flow perfusion, but its effects on the blood supply of expanded skin remain unclear. Therefore, this study aimed to evaluate the effects of BTX-A on blood flow perfusion during and after expansion.Methods Eighteen Sprague-Dawley rats were randomly divided into a BTX-A group and a control group. BTX-A or normal saline was injected intradermally into the marked skin on the back immediately. Then expanders were implanted in the rats. One week later, inflation of the expander with normal saline was started and performed twice a week to reach an intracapsular pressure of 8 kPa. The skin blood flow was measured before each injection. After 4 weeks of expansion, the sample was harvested for histological staining to measure the diameter and density of blood vessels; meanwhile, a 2 cm× 8 cm expanded random flap was elevated and sutured in situ. Blood flow perfusion and flap survival were observed.Results Compared with the control group, the BTX-A group had more blood flow, a larger blood vessel diameter, and higher blood vessel density in the expanded skin. Additionally, the flap of the BTX-A group had good blood flow perfusion and a high proportion of flap survival area within 7 days after expanded flap transfer. Data were analyzed using an independent t-test.Conclusion Pre-surgical BTX-A treatment may increase angiogenesis and vasodilatation, with subsequent blood perfusion elevation during and after expansion, and obtain a greater proportion of survival area of the transferred expanded flap.

Effect of botulinum toxin type A on flap surgery in animal models: a systematic review and meta-analysis

Flaps are common technical choices in aesthetic and reconstructive surgeries. However, the poor flap survival rate remains to be a difficult issue that troubles plastic surgeon. Recent research evidence supports that the use of Botulinum toxin type A (BTXA) can increase the flap survival rate. For verification, the present study was carried out to evaluate the effect of BTXA on flap surgery. Eight databases (PubMed, Cochrane Library, Ovid, Web of Science, Embase, Scopus, CBM, CNKI and WANFANG database) were searched for related published literature up to September 2020. A meta-analysis was then conducted to compare the effect of using BTXA with that of using saline or no treatment in flap surgery. Seventeen studies with a total of 565 animals were finally included in this review after strict exclusion and inclusion. Compared with saline/no treatment + flap group, BTXA + flap group showed a significantly higher flap tissue survival rate (mean difference [MD] 15.55, p < 0.00001), blood flow (standardized mean difference [SMD] 1.97, p < 0.00001) and vascular endothelial growth factor (VEGF) expression (at mRNA level: SMD 6.01, p = 0.02; at protein level: SMD 3.35, p < 0.00001). BTXA combined with flap surgery may have a positive effect on improving the flap tissue survival rate, blood flow of flaps and VEGF expression. Besides, the timing of BTXA injection may be an important factor for exerting its effect on flap surgery.

The Use of Botulinum Toxin to Prevent Anastomotic Thrombosis and Promote Flap Survival: A Bridge to Developing Clinical Studies

BACKGROUND

Despite the possibility of using botulinum toxin to improve perfusion and prevent vasospasm, only a few studies have examined the use of botulinum toxin in the setting of flap surgery and thrombosis, and the mechanisms have not been fully explained.

OBJECTIVE

The primary objective of this study was to provide a comprehensive review of the effectiveness of botulinum toxin in anastomotic thrombosis prevention and surgical flap survival to determine the value of conducting large-scale human trials.

METHODS

Using the SYRCLE and CAMRADES criteria, a systematic review was performed. PubMed, Medline, EmBase, and the Cochrane Library were searched for studies that met our eligibility criteria.

RESULTS

Twenty studies were included in the final selection. A total of 397 subjects were included. Eighteen studies used botulinum toxin type A alone, one used botulinum toxin type B alone, and only one used both botulinum toxin type A and botulinum toxin type B. The most commonly used injection technique was a preoperative intradermal injection. The most common procedure performed was a pedicled flap with random pattern skin flaps (65%). The mean injection dose was 28.17 ± 49.21 IU, whereas the mean reported injection time for studies using animal models was 7.4 ± 6.84 days.

CONCLUSIONS

Similar mechanisms demonstrated in animal models may be replicable in humans, allowing botulinum toxin to be used to prolong flap survival. However, many factors, such as optimal injection techniques, dosages, and long-term outcomes of botulinum use in flap surgery, need to be further assessed before applying this to clinical practice.

The Effect of Botulinum Toxin on Flap Viability of the Posterior Thigh Perforator Flap in Rats

BACKGROUND

The use of perforator propeller flaps in lower limb reconstruction has increased recently. Many pharmacological agents are used to increase flap viability. Botulinum toxin has been used in various types of flaps in the literature. However, there is no study regarding the use of botulinum toxin in the lower limb propeller flaps. This study investigates the effect of botulinum toxin administration on flap survival for lower limb propeller flap in rats.

MATERIALS AND METHODS

The study included 20 male Wistar albino rats, divided into two groups with a flap rotation of 90° in group 1 and 180° in group 2. In both groups, botulinum toxin was administered to the right thigh and a physiological saline solution was applied to the left thigh. Five days later, flaps were elevated over the posterior aspect of the right and left thighs and inset after 90° and 180° rotation was performed. Histopathological, immunohistochemical, and necrosis area analyses were performed.

RESULTS

Necrosis area, edema, polymorphonuclear leukocyte infiltration, and necrosis were found to be higher on the left side of the groups, whereas epidermal thickness, collagen density, vascularization, and hair root density were found to be higher on the right side of the groups. No significant difference was found between the right posterior thighs in either group on any parameter other than vascularization. Histopathologically and immunochemically statistically significant differences were found between the two groups.

CONCLUSIONS

The present study found that botulinum toxin increases flap viability in lower limb perforator-based propeller flaps.

Exenatide improves random-pattern skin flap survival via TFE3 mediated autophagy augment

Random-pattern skin flaps are widely applied to rebuild and restore soft-tissue damage in reconstructive surgery; however, ischemia and subsequent ischemia-reperfusion injury lead to flap necrosis and are major complications. Exenatide, a glucagon-like peptide-1 analog, exerts therapeutic benefits for diabetic wounds, cardiac injury, and nonalcoholic fatty liver disease. Furthermore, Exenatide is a known activator of autophagy, which is a complex process of subcellular degradation that may enhance the viability of random skin flaps. In this study, we explored whether exenatide can improve skin flap survival. Our results showed that exenatide augments autophagy, increases flap viability, enhances angiogenesis, reduces oxidative stress, and alleviates pyroptosis. Coadministration of exenatide with 3-methyladenine and chloroquine, potent inhibitors of autophagy, reversed the beneficial effects, suggesting that the therapeutic benefits of exenatide for skin flaps are due largely to autophagy activation. Mechanistically, we identified that exenatide enhanced activation and nuclear translocation of TFE3, which leads to autophagy activation. Furthermore, we found that exenatide activates the AMPK-SKP2-CARM1 and AMPK-mTOR signaling pathways, which likely lead to exenatide's effects on activating TFE3. Overall, our findings suggest that exenatide may be a potent therapy to prevent flap necrosis, and we also reveal novel mechanistic insight into exenatide's effect on flap survival.

Inhibition of skin fibrosis in systemic sclerosis by botulinum toxin B via the suppression of oxidative stress

Oxidative stress has been reported to play an important role in the pathogenesis of skin fibrosis in systemic sclerosis (SSc). We previously identified that botulinum toxin (BTX) injection suppresses pressure ulcer formation in a cutaneous ischemia-reperfusion injury mouse model by regulation of oxidative stress. However, the therapeutic possibility of BTX administration for preventing skin fibrosis in SSc is unclear. The objective of this study was to investigate the effect of BTX-B on skin fibrosis in a murine model of SSc and determine the underlying mechanism. We found that BTX-B injection significantly reduced dermal thickness and inflammatory cell infiltration in bleomycin-induced skin fibrosis lesion in mice. We also identified that the oxidative stress signal detected through bioluminescence in OKD48 mice after bleomycin injection in the skin was significantly decreased by BTX-B. Additionally, mRNA levels of oxidative stress associated factors (NOX2, HO-1, Trx2) were significantly decreased by BTX-B. Apoptotic cells in the lesional skin of bleomycin-treated mice were significantly reduced by BTX-B. Oxidant-induced intracellular accumulation of reactive oxygen species in SSc fibroblasts was also inhibited by BTX-B. In conclusion, BTX-B might improve bleomycin-induced skin fibrosis via the suppression of oxidative stress and inflammatory cells in the skin. BTX-B injection may have a therapeutic effect on skin fibrosis in SSc.

Application of Botulinum Neurotoxin Injections in TRAM Flap for Breast Reconstruction: Intramuscular Neural Arborization of the Rectus Abdominis Muscle

Breast reconstruction after mastectomy is commonly performed using transverse rectus abdominis myocutaneous (TRAM) flap. Previous studies have demonstrated that botulinum neurotoxin injections in TRAM flap surgeries lower the risk of necrosis and allow further expansion of arterial cross-sectional diameters. The study was designed to determine the ideal injection points for botulinum neurotoxin injection by exploring the arborization patterns of the intramuscular nerves of the rectus abdominis muscle. A modified Sihler's method was performed on 16 rectus abdominis muscle specimens. Arborization of the intramuscular nerves was determined based on the most prominent point of the xyphoid process to the pubic crest. All 16 rectus abdominis muscle specimens were divided into four muscle bellies by the tendinous portion. The arborized portions of the muscles were located on the 5-15%, 25-35%, 45-55%, and 70-80% sections of the 1st, 2nd, 3rd, and 4th muscle bellies, respectively. The tendinous portion was located at the 15-20%, 35-40%, 55-60%, and 90-100% sections. These results suggest that botulinum neurotoxin injections into the rectus abdominis muscles should be performed in specific sections.

Chemically Modified SDF-1α mRNA Promotes Random Flap Survival by Activating the SDF-1α/CXCR4 Axis in Rats

Random skin flaps are frequently applied in plastic and reconstructive surgery for patients suffering from soft tissue defects caused by congenital deformities, trauma and tumor resection. However, ischemia and necrosis in distal parts of random skin flaps remains a common challenge that limits the clinical application of this procedure. Recently, chemically modified mRNA (modRNA) was found to have great therapeutic potential. Here, we explored the potential of fibroblasts engineered to express modified mRNAs encoding the stromal cell-derived factor-1α (SDF-1α) to improve vascularization and survival of therapeutic random skin flaps. Our study showed that fibroblasts pre-treated with SDF-1α modRNA have the potential to salvage ischemic skin flaps. Through a detailed analysis, we revealed that a fibroblast SDF-1α modRNA combinatorial treatment dramatically reduced tissue necrosis and significantly promoted neovascularization in random skin flaps compared to that in the control and vehicle groups. Moreover, SDF-1α modRNA transcription in fibroblasts promoted activation of the SDF-1α/CXCR4 pathway, with concomitant inactivation of the MEK/ERK, PI3K/AKT, and JAK2/STAT3 signaling pathways, indicating a possible correlation with cell proliferation and migration. Therefore, fibroblast-mediated SDF-1α modRNA expression represents a promising strategy for random skin flap regeneration.

Suppression of neuropeptide by botulinum toxin improves imiquimod-induced psoriasis-like dermatitis via the regulation of neuroimmune system

BACKGROUND

Psoriasis is a multifactorial disease arises from a complex interaction of genetics, immune system, and environmental aspects. IL-23/Th17 immune axis has been considered as a primary modulator in psoriasis. In addition, several findings imply that nervous system may take a part in the pathogenesis of psoriasis, suggesting that nervous system, through its neuropeptide, may interact with immune system and lead to the formation of psoriasis.

OBJECTIVE

We aimed to ascertain the role of neuropeptides secreted from neurons in the pathogenesis of psoriasis in vivo.

METHODS

The release of neuropeptide was inhibited by injecting Botulinum toxin B (BTX-B) on Imiquimod (IMQ)-induced psoriasis-like dermatitis mice model. Quantification of skin dermatitis, infiltrating inflammatory cells, and the production of cytokines at the lesional skin area were performed by PSI score, immunostaining, and real-time PCR. We also tested the effect of selective CGRP antagonist (CGRP_8-37) on psoriasis-like dermatitis in IMQ-treated mice.

RESULTS

BTX-B injection significantly suppressed PSI score and reduced the number of CD4⁺ T cells, CD11c⁺ dendritic cells, and the production of IL-17A/F in the lesional skin. The expressions of PGP9.5⁺ nerve fibers and neuropeptides (SP, CGRP) were also significantly reduced following BTX-B injection. Additionally, CGRP antagonist also suppressed the development of IMQ-induced psoriasis-like dermatitis in mice.

CONCLUSION

The suppression of neuropeptide secretion in the skin by BTX injection might inhibit nerve elongation, the infiltration of immune cells, as well as IL-17 production, resulting in the improvement of psoriasis. Neuropeptide inhibitor could also be applied to the treatment of psoriasis.

Preconditioning with Foam-mediated External Suction on Flap Microvasculature and Perfusion in a Rodent Model

Foam-mediated external suction (FMES) has previously shown to improve tissue microcirculation. We hypothesized that preconditioning fasciocutaneous perforator flaps with FMES would augment perfusion and demonstrate greater capillary recruitment.

Perspectives for the use of therapeutic Botulinum toxin as a multifaceted candidate drug to attenuate COVID-19

The recent outbreak of coronavirus disease (COVID-19) resulting from a distinctive severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to evolve in many countries and pose life-threatening clinical issues to global public health. While the lungs are the primary target for the SARS-CoV-2-mediated pathological consequence, the virus appears to invade the brain and cause unpredicted neurological deficits. In the later stage, COVID-19 can progress to pneumonia, acute respiratory failure, neurodegeneration and multi-organ dysfunctions leading to death. Though a significant portion of individuals with COVID-19 has been recovering from clinical symptoms, the pathological impact of the SARS-CoV-2 infection on the structural and functional properties of the lungs, heart, brain and other organs at the post-recovery state remains unknown. Presently, there is an urgent need for a remedial measure to combat this devastating COVID-19. Botulinum toxins (BoNTs) are potent neurotoxins that can induce paralysis of muscle and acute respiratory arrest in humans. However, a mild dose of the purified form of BoNT has been known to attenuate chronic cough, dyspnoea, pneumonia, acute respiratory failure, abnormal circulation, cardiac defects and various neurological deficits that have been recognised as the prominent clinical symptoms of COVID-19. Considering the fact, this review article provides 1) an overview of the SARS-CoV-2 mediated pathological impact on the lungs, heart and brain, 2) signifies the therapeutic uses of BoNTs against pulmonary failure, cardiac arrest and neurological deficits, and 3) emphasize the rationality for the possible use of BoNT to prevent SARS-CoV-2 infection and manage COVID-19.

Effect of Botulinum Toxin-A Injected to Muscle Tissue on Perfusion and Survival of Fasciocutaneous Single Perforator-pedicled Propeller Flap in Rats

Background:

In plastic surgery practice, fasciocutaneous single-perforator-pedicled propeller flap is a preferred procedure; however, its survival rate is below than expected, especially in flaps with a big rotation arc. When botulinum toxin-A is injected into the muscle tissue that the perforator pedicle is arisen, the tonus of pertinent muscle can reduce and the blood flow of its perforator pedicle can increase. Therefore this procedure can improve the survival rate of single-perforator-pedicled propeller flap.

Aims:

To evaluate the effect of botulinum toxin-A injected with ultrasonographic guidance into the muscle tissue that the perforator pedicle is arisen from one month ago on the perfusion of flap scintigraphically and the survival rate of single-perforator-pedicled propeller flap in a rat model.

Study Design:

Animal experiment.

Methods:

Three study groups were receiving botulinum toxin-A (16 IU-0.4 mL), normal saline (0.4 mL), and no study drug one month ago before flap surgery. Injections were performed under ultrasonography guidance. Flaps were elevated fasciocutaneously over the right 2nd perforator pedicle, under the corneous, with a surgical loupe and microsurgery tool and were rotated clockwise 180°. Then the scintigraphic measurements were obtained after flap elevations in the study groups, including the whole-body and flap perfusions in the study rats. The involvement rate presents the ratio of flap perfusion to whole-body perfusion. Flaps were sutured back to the abdominal wall at the latest twisting angles. With standard photographs taken in all the groups on day 8 after the operation, whole and necrotic flap areas were calculated.

Results:

Scintigraphically the involvement rate (the ratio of flap perfusion to whole-body perfusion) of the flaps in the botulinum toxin-A group were found significantly higher than those in the other groups (p<0.05). The area of a flap in the botulinum toxin-A group on day 8 post flap suturing was found to be significantly higher than those in the other groups (p<0.05). The area of a necrosis and the percentage of necrosis on day 8 post flap suturing in the botulinum toxin-A group was found significantly lower than those of the sham and null groups (p<0.05).

Conclusion:

In a rat model, if with the ultrasonographic guidance, botulinum toxin-A is injected to the muscle which perforator of the prospective single-perforator-pedicled propeller flap originated and flap surgery is performed one month later after this injection, the perfusion of single-perforator-pedicled propeller flap increases scintigraphically and this improves flap survival and reduces its necrosis.

Improving the Retention Rate of Fat Grafts in Recipient Areas via Botulinum Toxin A Treatment

BACKGROUND

Improving the retention rate of transplanted fat is, currently, of great concern. Partial immobilization, angiogenesis, and adipose tissue-derived stem cells, all proven to be influenced by botulinum toxin A (BTX-A), are significant in fat graft retention.

OBJECTIVES

The authors sought to determine the impact of BTX-A on fat grafts.

METHODS

Our study included 12 Sprague Dawley rats and each rat's hind limbs were randomly designated as the BTX-A side and control side. We injected 0.2 mL of BTX-A-treated fat into the quadriceps femoris and subcutaneous space of the BTX-A sides. This was also done for the control sides but with untreated fat. We performed electroneuromyography of recipient muscles at 1 week post-operation. The rats were euthanized at 12 weeks post-operation and we observed the fat retention rate, the fat's histologic characteristics, and the density of vessels and mature adipocytes.

RESULTS

The amplitudes of electroneuromyography were smaller for the BTX-A sides than the control sides. For intramuscularly injected fat, the BTX-A sides had better retention rates and histologic characteristics and a higher density of vessels and mature adipocytes than the control sides. For subcutaneously injected fat, the BTX-A sides had better histologic characteristics and a higher density of vessels and mature adipocytes than the control sides, but the retention rates were not significantly different between the 2 sides.

CONCLUSIONS

Injecting BTX-A-treated fat grafts can immobilize the surrounding muscles. BTX-A can improve the density of vessels and mature adipocytes, histologic characteristics of fat grafts, and retention rate of fat grafts transplanted into muscles.

Botulinum Toxin Type A Attenuates Apoptosis in Human Dermal Microvascular Endothelial Cells Exposed to an In Vitro Model of Ischemia/Reperfusion Injury

BACKGROUND

Botulinum toxin type A (BTXA) has been reported to increase survival of critically ischemic skin flaps; however, the effect of BTXA in human dermal microvascular endothelial cells (HDMECs) remains to be investigated. This study aimed to investigate the protective effect of BTXA in HDMECs exposed to an in vitro model of ischemia/reperfusion injury.

METHODS

HDMECs were isolated from human upper eyelid tissue and were randomly divided into 3 groups: 1.

CONTROL GROUP

culture under normoxic conditions (95% air and 5% CO₂); 2. hypoxia/reoxygenation (H/R) group: culture in a hypoxic incubator (94% N₂ + 5% CO₂ + 5% O₂) for 8 hours, followed by culture in saturated aerobic culture medium for 24 hours; and 3. BTXA group: treatment with BTXA for 12 hours before exposure to hypoxic conditions. Flow cytometry was used to analyze the apoptosis of HDMECs, and western blotting was used to detect the expression of apoptosis-related proteins.

RESULTS

H/R leads to severe injury in HDMECs, as evidenced by an increase in the percentage of apoptosis and an increase in expression of apoptosis-related proteins (Bax, cleaved-caspase-3, and cytochrome C). Moreover, H/R results in a decrease in expression of anti-apoptotic protein (Bcl-2), which can be significantly attenuated with BTXA treatment.

CONCLUSION

BTXA protects against apoptosis in HDMECs exposed to an in vitro model of H/R-induced injury.

Effect of Perivascular Injection of Botulinum Toxin Type A versus Lidocaine in Survival of Random Pattern Flaps in a Rat Model

BACKGROUND

Botulinum toxin type A has gained popularity in many clinical fields, for a variety of aesthetic and therapeutic purposes. In addition, there have been reports regarding the positive effect of botulinum toxin type A on flap survival by various mechanisms. This study examines the role of botulinum toxin type A and lidocaine in augmentation of flap survival and decreasing the rate of necrosis in random pattern cutaneous flaps.

METHODS

In 45 male Sprague-Dawley rats, random pattern skin flaps with different width-to-length ratios were elevated. Botulinum toxin type A, lidocaine, or saline was administered to the base and whole length of the flap. Flap survival was evaluated on day 10 after surgery. The area of flap survival was determined grossly on the basis of its appearance, color, and texture.

RESULTS

The botulinum toxin type A group had a greater survival area (p < 0.05) compared with the lidocaine or saline group in flaps with width-to-length ratios of 1:2 and 1:3; however, compared with a width-to-length ratio of 1:1, the flap survival rate shows no statistically significant variations.

CONCLUSION

Injection of botulinum toxin type A in random pattern skin flaps improves tissue perfusion and increases the rate of flap survival more than lidocaine in flaps with width-to-length ratios of 1:2 and 1:3.

The Use of Botulinum Toxin in Flap Surgery: A Review of the Literature

Botulinum neurotoxin-A and botulinum neurotoxin-B have been shown to play a potential role in improving flap survival in animal models. The aim of this study is to review indications as well as to study injection timing, technique, and doses of botulinum neurotoxin-A and botulinum neurotoxin-B in animal models. Seventeen articles describe a total of 266 animals that underwent botulinum toxin injections before or during flap harvesting or vascular anastomosis procedure. All the studies demonstrated a beneficial effect of botulinum toxin administration in flap surgery or vascular anastomosis. Botulinum neurotoxin-A injection was shown to be a reliable approach in reducing vascular complications rate and increasing survival of flaps in animal models. The main conclusions drawn from the study include the following: perivascular injections targeting each vascular pedicle are preferred in cases of free flaps or axial flaps; subdermal injections are favorable in cases of random pattern skin flaps; and injections should be performed 7 days before flap elevation.

Role of botulinum neurotoxin-A in cerebral revascularization graft vasospasm prevention: current state of knowledge

Graft stenosis and occlusion remain formidable complications in cerebral revascularization procedures, which can lead to significant morbidity and mortality. Graft vasospasm can result in early postoperative graft stenosis and occlusion and is believed to be at least partially mediated through adrenergic pathways. Despite various published treatment protocols, there is no single effective spasmolytic agent. Multiple factors, including anatomical and physiological variability in revascularization conduits, patient age, and comorbidities, have been associated with graft vasospasm pathogenesis and response to spasmolytics. The ideal spasmolytic agent thus likely needs to target multiple pathways to exert a generalizable therapeutic effect. Botulinum toxin (BTX)-A is a powerful neurotoxin widely used in clinical practice for the treatment of a variety of spastic conditions. Although its commonly described paradigm of cholinergic neural transmission blockade has been widely accepted, evidence for other mechanisms of action including inhibition of adrenergic transmission have been described in animal studies. Recently, the first pilot study demonstrating clinical use of BTX-A for cerebral revascularization graft spasm prevention has been reported. In this review, the mechanistic basis and potential future clinical role of BTX-A in graft vasospasm prevention is discussed.

Relaxation matters: comparison of in-vitro vasodilatory role of botulinum toxin-A and papaverine in human radial artery grafts

Background

Radial artery (RA) is widely used in coronary artery bypass (CABG) surgery and the prevention of spasm is crucial for graft patency. Botulinum toxin A (BTX-A) and B are commonly used for aesthetic reasons and neuromuscular disorders. They are proven to raise blood flow and increase survival of ischemic skin flaps. In this study we evaluated and compared the vasodilator effects of BTX-A and papaverine on human RA grafts.

Methods

After resting 60 min in isolated organ baths, human RA grafts were examined. Contraction responses for different doses of serotonin (5-HT) and endothelin-1 (ET-1) were evaluated as a percent of maximum contraction response elicited by 80 mM potassium chloride (KCl). The inhibitory effects of BTX-A and papaverine on contraction responses taken at the 0th hour were compared with the 1st and 2nd hour responses. Inhibitory effects of BTX-A and papaverine against the contractile agent were evaluated by comparing the results of the first and last (0th and 2nd hour) application.

Results

In low concentrations, when we compared the effects of BTX-A (10^− 8 M) and papaverine (10^− 6 M) on 5-HT, papaverine was found to be more effective at both the 0th and 2nd hour (p < 0.05). Both BTX-A and papaverine inhibited the maximum contractile effect of ET-1 to the same extent at the 0th hour; but, the inhibitory effect of BTX-A was significantly stronger at the 2nd hour (p < 0.05).

In high concentrations, when we compared the effects of BTX-A (10^− 6 M) and papaverine (10^− 4 M) on 5-HT, papaverine showed stronger inhibition (p < 0.05), whereas both agents had similar action of inhibition on ET-1 mediated maximum contraction responses.

Conclusion

BTX-A inhibits both ET-1 and 5-HT induced contractions and its effectiveness does not decrease over time as observed with papaverine. This study is the first in the literature using human RA for prevention of vasospasm by BTX-A.

Botulinum toxin type A induces protective autophagy in human dermal microvascular endothelial cells exposed to an in vitro model of ischemia/reperfusion injury

Botulinum toxin type A (BTXA) has been reported to increase the survival of ischemic skin flaps; however, the exact mechanism underlying this effect remains unclear and needs to be further established. The present study aimed to elucidate whether autophagy caused by BTXA functions as a protection mechanism and to identify the mechanisms of its regulation by BTXA in human dermal microvascular endothelial cells (HDMECs) subjected to hypoxia/reoxygenation (H/R)-induced injury. HDMECs were harvested from the upper eyelid tissues of female blepharoplasty patients. HDMECs were exposed to BTXA treatment for 12 h and then subjected to hypoxia for 8 h, followed by reoxygenation for 24 h. Chloroquine diphosphate salt (CQ) was used as an autophagy inhibitor. H/R led to extreme injury to the HDMECs as indicated by the rise in the apoptosis rate, which was significantly attenuated by BTXA pretreatment. The outcomes demonstrated that H/R caused autophagy, as evidenced by a higher type II/type I ratio of light chain 3 (LC3), increased expression of Beclin-1 and increased autophagosome formation. BTXA enhanced autophagy and attenuated apoptosis in a dose-dependent manner, whereas CQ attenuated the BTXA antiapoptotic effects and inhibited the formation of autophagolysosomes, which caused clustering of the LC3-II in cells. In conclusion, autophagy promoted by BTXA serves as a potential protective effect on ischemia/reperfusion injury.

Botulinum toxin B suppresses the pressure ulcer formation in cutaneous ischemia-reperfusion injury mouse model: Possible regulation of oxidative and endoplasmic reticulum stress

BACKGROUND

We previously identified that botulinum toxin A (BTX-A) suppressed pressure ulcer (PU) formation after cutaneous ischemia-reperfusion (I/R) injury; however, regulation of cutaneous I/R-induced oxidative and endoplasmic reticulum (ER) stress by BTX-B was not investigated. Additionally, the efficacy of BTX-B injection has never been examined.

OBJECTIVE

Objective was to assess the effects of BTX-B on the formation of PU by cutaneous I/R injury, and the regulation of oxidative and ER stress in I/R injury by BTX-B.

METHODS

BTX-B was subcutaneously injected into I/R area, and wound size, vascular damage, hypoxic area, and apoptotic cells in I/R area were analyzed. We evaluated the extent of oxidative and ER stress in I/R area by using OKD48 mice and ERAI mice, respectively, which enabled evaluating oxidative and ER stress through bioluminescence detection.

RESULTS

BTX-B injection significantly suppressed the formation of PU by cutaneous I/R injury. Cutaneous I/R-induced vascular damage, hypoxic area, and number of oxidative-damaged cells and apoptotic cells were suppressed by BTX-B injection. BTX-B administration significantly inhibited I/R-induced oxidative stress signal in OKD48 mice. BTX-B reduced the I/R-induced oxidative stress-associated factors. BTX-B significantly inhibited the oxidant-induced reactive oxygen species and apoptosis of endothelial cells and fibroblasts. BTX-B significantly inhibited I/R-induced ER stress signal in ERAI mice. Cutaneous I/R injury-induced ER stress-response factors and GRP78/BiP and CHOP-positive cells in I/R area were significantly decreased by BTX-B injection.

CONCLUSION

BTX-B injection might have protective effects against PU formation after cutaneous I/R injury by reducing vascular damage, hypoxia-induced oxidative and ER stress, and apoptosis.

Beneficial effect of botulinum toxin A on secondary ischaemic injury of skin flaps in rats

Botulinum toxin A (BTX-A) protects against primary ischaemia of skin flaps, but its effect on secondary ischaemia is unknown. We induced secondary arterial or venous ischaemia in skin flaps of 32 Wistar rats, and tested the effectiveness of BTX injected subcutaneously 12hours before the flap was raised. The animals were divided into two groups of 16 (arterial or venous). Eight animals in each group were then treated with saline 1ml (control), and eight with BTX-A 5 IU (treatment). Ischaemia and necrosis were assessed after five days. There was no significant difference in necrosis between the two treatments in either group, but the amount of ischaemia did differ significantly (p=0.031 in the artetial ishcemia and p=0.015 in the venous ischemia group). BTX helped to salvage poor reperfusion in secondary ischaemia of skin flaps.

Microcirculatory Effects of Botulinum Toxin A in the Rat: Acute and Chronic Vasodilation

BACKGROUND

Botulinum toxin-A (BTX) has numerous cosmetic and therapeutic applications. Our previous studies have found that BTX augments pedicled flap survival through both vasodilatory effects and attenuation of the inflammatory response to ischemia in the rat. This study examines the effect of chronic BTX on microcirculatory vascular tone and its response to acute topical vasodilators in muscle flaps.

METHODS

The spinotrapezius muscle of Sprague-Dawley rats underwent a single 2-week pretreatment of 0.2 mL saline either with (n = 5) or without (n = 5) 2u BTX. After surgical elevation, an arcade arteriole was observed using a video caliper device. Vessel diameter was measured at 30-second intervals after sequential superfusion of nitroglycerin (100 and 200 μg/mL), multiple concentrations of lidocaine, and a combination of adenosine (10 μM) and nitroprusside (10 μM) to induce maximum dilation.

RESULTS

Baseline and dilation diameters were expressed as ratios of pharmacologically induced maximum dilation, whereas percent dilation was defined as the change in diameter over baseline diameter. We found a significant increase in resting diameter with BTX pretreatment (P = 0.0028). Compared with the control group, mean baseline diameter was 15% greater, and percent dilation was 25% less in BTX-pretreated flaps. There was no significant relationship between BTX pretreatment and dilation diameter (P = 0.2895) after adjusting for the effect of acute vasodilators.

CONCLUSIONS

Pretreatment with BTX may induce the arteriolar resting diameter to be closer to their maximum potential diameter. Additionally, BTX does not display a synergistic effect with topical vasodilators on vasodilation.

Botulinum Toxin A Upregulates Rac1, Cdc42, and RhoA Gene Expression in a Dose-Dependent Manner: In Vivo and in Vitro Study

Angiogenesis is the development of new capillaries from existing blood vessels and is a prerequisite for the wound-healing process. Many lines of scientific evidences have shown that complicated roles of small guanosine triphosphatases (GTPases) (ras-related C3 botulinum toxin substrate 1 [Rac1], cell division control protein 42 [Cdc42], and ras homolog gene family, member A [RhoA]) in regulation of signal transduction pathways exist to transmit distinct cellular effects on the modulation of actin cytoskeleton remodeling such as cell cycle progression, cell survival, and cell motility. In addition, these small GTPases activate mitogen-activated protein kinase kinase kinases (MAP3Ks) leading to activated mitogen-activated protein kinase kinases (MAPKK), mitogen-activated protein kinase (MAPK), and various transcription factors such as vascular endothelial growth factor with involvement of MAPK signaling pathways.In this study, the authors hypothesized that botulinum toxin A increases angiogenesis via the expression of small GTPases in vivo and in vitro studies.In vivo experiment, 24 Sprague-Dawley rats were randomly divided into 2 groups: a control group and a botulinum toxin A group. Five days prior to superiorly based transverse rectus abdominis myocutaneous flap elevation, the botulinum toxin A (BoTA) group was pretreated with BoTA, while the control group was pretreated with normal saline. quantitative real-time polymerase chain reaction was performed to evaluate the expression of Rac1, RhoA, and Cdc42.The angiogenic effects of botulinum toxin A on human dermal fibroblasts were measured in vitro experiment. To understand the mechanism of botulinum toxin A on small GTPases production of fibroblasts, Rac1, Cdc42, and RhoA were measured using qRT-PCR.The relative messenger ribonucleic acid expression of Rac1, RhoA, and Cdc42 was significantly higher in the BoTA group than in the control group, in every zone and pedicle muscle, on postoperative days 1, 3, and 5. Levels of these molecules increased significantly in human dermal fibroblasts grown in the presence of BoTA compared with control group over 5 IU.Our in vivo and in vitro studies suggest that administration of BoTA upregulates the expression of RhoA, Rac1, and Cdc42 in a dose-dependent manner. MAPK signaling pathway might be involved in BoTA-induced angiogenesis mechanism.

LEVEL OF EVIDENCE

N/A.

Impact of botulinum toxin A injection on esophageal anastomosis in a rabbit model

PURPOSE

The management of esophageal atresia is established, but the rate of postoperative complications remains high. We focused on a new, recently reported method of esophageal elongation using botulinum toxin type A (BTX-A) and evaluated the efficacy of BTX-A injection around esophageal anastomoses with tension in a rabbit model.

METHODS

Twenty rabbits aged 8-10 weeks and weighing 1.27-1.72 kg underwent resections of the esophagus measuring 1.5 cm long using an anterior cervical approach. Esophagoesophagostomies were performed after intramural administration of Xeomin™ (3 U/body) in the BTX-A group and saline in the control group. Morphological and histological evaluations were examined on postoperative day 14.

RESULTS

Six rabbits in each group survived. The BTX-A group showed significantly less postoperative anastomotic stricture and less fibrosis than the control group. Changes in wall thickness on both sides of the anastomotic areas were equivalent between the two groups, and no muscle fracturing was observed.

CONCLUSION

Local administration of BTX-A for esophagoesophagostomy significantly reduced postoperative anastomotic stricture with less fibrosis than that observed in the control group. Reduced anastomotic tension with BTX-A presumably contributed to better anastomotic healing. Determining the optimum dose of BTX-A is necessary for clinical application.

Effect of botulinum toxin A and nitroglycerin on random skin flap survival in rats

BACKGROUND

A suitable pharmacological substitute for the well-established surgical delay technique for random skin flaps to increase viability has been elusive.

OBJECTIVE

To evaluate the effects of nitroglycerin and botulinum toxin type A on random flap survival in a rat model.

METHODS

The present controlled experimental study was performed in the four groups of rats. One week after intervention in each group, the flap was raised and kept in situ, and flap necrosis was evaluated through follow-up. Group 1 received intradermal botulinum toxin type A (BTX-A) and topical nitroglycerin 2%; group 2 received BTX-A and topical Vaseline (Unilever, USA); group 3 received topical nitroglycerin and intradermal normal saline; and group 4 received topical Vaseline and intradermal normal saline.

RESULTS

BTX-A reduced the area of necrosis compared with control (24% versus 56% respectively; P<0.001). Nitroglycerin application was associated with a trend toward improved flap viability (42% versus 56%; P=0.059). The combination of topical nitroglycerin and BTX-A, compared with Vaseline and BTX-A, was associated with decreased flap necrosis (16.1% versus 24%, respectively), although it was not statistically significant (P=0.45).

CONCLUSIONS

BTX-A was effective in reducing distal flap necrosis. The effect of BTX-A was significantly more pronounced than nitroglycerin ointment.

Effect of botulinum toxin a and nitroglycerin on random skin flap survival in rats

Background

A suitable pharmacological substitute for the well-established surgical delay technique for random skin flaps to increase viability has been elusive.

Objective

To evaluate the effects of nitroglycerin and botulinum toxin type A on random flap survival in a rat model.

Methods

The present controlled experimental study was performed in the four groups of rats. One week after intervention in each group, the flap was raised and kept in situ, and flap necrosis was evaluated through follow-up. Group 1 received intradermal botulinum toxin type A (BTX-A) and topical nitroglycerin 2%; group 2 received BTX-A and topical Vaseline (Unilever, USA); group 3 received topical nitroglycerin and intradermal normal saline; and group 4 received topical Vaseline and intradermal normal saline.

Results

BTX-A reduced the area of necrosis compared with control (24% versus 56% respectively; P<0.001). Nitroglycerin application was associated with a trend toward improved flap viability (42% versus 56%; P=0.059). The combination of topical nitroglycerin and BTX-A, compared with Vaseline and BTX-A, was associated with decreased flap necrosis (16.1% versus 24%, respectively), although it was not statistically significant (P=0.45).

Conclusions

BTX-A was effective in reducing distal flap necrosis. The effect of BTX-A was significantly more pronounced than nitroglycerin ointment.

Human Adipose-Derived Mesenchymal Stromal Cells May Promote Breast Cancer Progression and Metastatic Spread

BACKGROUND

Stem cell-enriched fat grafting has been proposed as a potential therapy for reconstructive, restorative, or enhancement-related procedures of the breast. Its role in postoncologic breast reconstruction is still emerging, with concerns about safety. The authors investigated the dose-dependent interaction between human adipose-derived mesenchymal stromal cells (AD-MSCs) and human breast cancer cell (BCC) lines [MDA-MB-231 (MDA) and MCF-7 (MCF)] focusing on tumor microenvironment, tumor growth, and metastatic spread.

METHODS

Adipose-derived mesenchymal stromal cell influence on viability and factor expression [regulated on activation, normal T cell expressed and secreted (RANTES), tumor necrosis factor-α, and eotaxin) of breast cancer cells was studied in vitro using direct and indirect co-culture systems. Groups were formed according to adipose-derived mesenchymal stromal cell-to-cancer cell number ratio [MDA/MCF only, AD-MSC/(MDA/MCF), and AD-MSC/(MDA/MCF)]. A humanized orthotopic murine cancer model was used to evaluate breast cancer progression and metastasis (n = 10/group). Cells were injected into the mammary pad in different ratios and animals were monitored over 42 days. Microdialysis was performed to analyze RANTES levels in the tumor microenvironment (days 21 and 42). Primary and metastatic tumors were weighed and analyzed for oncogene, growth factor, and metastatic marker expression.

RESULTS

MDA cell viability increased from 45.5 percent to 95.5 percent in presence of adipose-derived mesenchymal stromal cells in vitro. In vivo, animals with AD-MSC showed increased mean tumor weight (MDA, p < 0.01; MCF versus controls, p < 0.05) and metastatic occurrence (40 percent in MDA; 30 percent in MCF versus 0 percent in controls). Cytokine analysis revealed switching of MCF tumor phenotype to a more malignant type in the presence of adipose-derived mesenchymal stromal cells.

CONCLUSION

Human adipose-derived mesenchymal stromal cells may promote progression and metastatic spread in breast cancer through a switch to a more malignant phenotype with worse prognosis.

Design and preliminary testing of a novel skin expander for total ear reconstruction in a rabbit model

BACKGROUND

Ear reconstruction is one of the most complicated and challenging techniques in plastic surgery because of the histologic and anatomic properties of the ear. Success depends on fitting the auriform cartilage scaffold into the overlying skin, but current approaches can just give results that are not lifelike and can lead to complications.

MATERIALS AND METHODS

A novel double-capsule, double-valve plastic ear expander was designed and implanted subcutaneously on either side of the dorsum of six New Zealand white rabbits (two expanders per rabbit). The outer capsule was expanded by injecting approximately 120 mL of physiological saline, then withdrawing the liquid on two occasions. Next, the ear-shaped inner capsule was filled with high-hardness plaster, and the external capsule was emptied such that the expanded skin flap and external capsule responded to the negative pressure and closed over the ear-shaped inner capsule. As a result, the skin flap adopted an ear shape. The ear expander was left in place for 4 wk, removed with the help of a mini-incision, and stripped of its fibrous capsule. To simulate human ear reconstruction, the expander was replaced with an auriform silicone prosthesis, and the effects of auricular reconstruction were observed dynamically.

RESULTS

All 12 skin flaps maintained abundant blood supply, created a clear outline of the ear framework, and produced a lifelike result. No complications were observed during the 4-wk observation period.

CONCLUSIONS

The expanded skin flaps described here can mold to the desired contours and appear lifelike, as well as maintain abundant blood supply. This may provide a simpler approach to total ear reconstruction that reduces risk of complications.

Protective effect of botulinum toxin A after cutaneous ischemia-reperfusion injury

Botulinum toxin A (BTX-A) blocks the release of acetylcholine vesicles into the synaptic space, and has been clinically used for aesthetic indications, neuromuscular disorders and hyperhidrosis. Several studies have demonstrated that BTX-A enhanced the blood flow and improved ischemia in animal models. Our objective was to assess the effects of BTX-A on cutaneous ischemia-reperfusion (I/R) injuries, mimicking decubitus ulcers. The administration of BTX-A in I/R areas significantly inhibited the formation of decubitus-like ulcer in cutaneous I/R injury mouse model. The number of CD31(+) vessels and αSMA(+) pericytes or myofibroblasts in wounds were significantly increased in the I/R mice treated with BTX-A. The hypoxic area and the number of oxidative stress-associated DNA-damaged cells and apoptotic cells in the I/R sites were reduced by BTX-A administration. In an in vitro assay, BTX-A significantly prevented the oxidant-induced intracellular accumulation of reactive oxygen species (ROS) in vascular endothelial cells. Furthermore, the administration of BTX-A completely suppressed the ulcer formation in an intermittent short-time cutaneous I/R injury model. These results suggest that BTX-A might have protective effects against ulcer formation after cutaneous I/R injury by enhancing angiogenesis and inhibiting hypoxia-induced cellular damage. Exogenous application of BTX-A might have therapeutic potential for cutaneous I/R injuries.

The role of botulinum toxin in vasospastic disorders of the hand

Raynaud phenomenon may be a primary disorder or associated with a variety of other autoimmune processes. Raynaud phenomenon produces digital vasospasm, which can lead to ischemia and ulceration. The treatment of Raynaud phenomenon has been difficult because multiple medical treatments have not provided uniform resolution of symptoms. Many patients have turned to surgery and sympathectomies for the treatment of unrelenting vasospasm. Botulinum toxin has been shown to be an effective alternative to surgery, with a single treatment being capable of resolving pain and healing ulcer. This article reviews the use of botulinum toxin for the treatment of Raynaud phenomenon.