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

Preliminary evidence for the presence of programmed cell death in pressure injuries

Pressure injuries (PIs) are a common healthcare problem worldwide and are considered to be the most expensive chronic wounds after arterial ulcers. Although the gross factors including ischemia-reperfusion (I/R) have been identified in the etiology of PIs, the precise cellular and molecular mechanisms contributing to PIs development remain unclear. Various forms of programmed cell death including apoptosis, autophagy, pyroptosis, necroptosis and ferroptosis have been identified in PIs. In this paper, we present a detailed overview on various forms of cell death; discuss the recent advances in the roles of cell death in the occurrence and development of PIs and found much of the evidence is novel and based on animal experiments. Herein, we also state critical evaluation of the existing data and future perspective in the field. A better understanding of the programmed cell death mechanism in PIs may have important implications in driving the development of new preventive and therapeutic strategies.

Keratinocyte-Specific SOX2 Overexpression Suppressed Pressure Ulcer Formation after Cutaneous Ischemia-Reperfusion Injury via Enhancement of Amphiregulin Production

Ischemia-reperfusion (I/R) injury is a key player in the pathogeneses of pressure ulcer formation. Our previous work demonstrated that inducing the transcription factor SOX2 promotes cutaneous wound healing through EGFR signaling pathway enhancement. However, its protective effect on cutaneous I/R injury was not well-characterized. We aimed to assess the role of SOX2 in cutaneous I/R injury and the tissue-protective effect of SOX2 induction in keratinocytes (KCs) in cutaneous I/R injury. SOX2 was transiently expressed in KCs after cutaneous I/R injury. Ulcer formation was significantly suppressed in KC-specific SOX2-overexpressing mice. SOX2 in skin KCs significantly suppressed the infiltrating inflammatory cells, apoptotic cells, vascular damage, and hypoxic areas in cutaneous I/R injury. Oxidative stress-induced mRNA levels of inflammatory cytokine expression were suppressed, and antioxidant stress factors and amphiregulin were elevated by SOX2 induction in skin KCs. Recombinant amphiregulin administration suppressed pressure ulcer development after cutaneous I/R injury in mice and suppressed oxidative stress-induced ROS production and apoptosis in vitro. These findings support that SOX2 in KCs might regulate cutaneous I/R injury through amphiregulin production, resulting in oxidative stress suppression. Recombinant amphiregulin can be a potential therapeutic agent for cutaneous I/R injury.

Botulinum toxin type A activates protective autophagy by modulating endoplasmic reticulum stress in hypoxia/reoxygenation-treated endothelial cells

Botulinum toxin type A (BTXA) previously protected endothelial cells in free skin flaps from ischemia/reperfusion injury by inducing autophagy. Endoplasmic reticulum (ER) stress-autophagy activation may have a role in BTXA-antagonized ischemia/reperfusion damage in human dermal microvascular endothelial cells (HDMECs), however, this has yet to be proven. HDMECs were pretreated with BTXA at various concentrations for 12 h before being subjected to hypoxia and reoxygenation (H/R). Cell Count Kit 8 (CCK8) and Western blot (WB) data showed that H/R treatment significantly increased the expression of ER stress (GRP78, CHOP) and autophagy (LC3II/I, Beclin-1) proteins. The optimal BTXA pretreatment concentration was 1.6 U/mL, which resulted in the highest levels of cell survival and expression of ER stress and autophagy. Following pretreatment with 1.6 U/mL BTXA and the addition of the ER stress inducer Thapsigargin (Tg), the ER stress inhibitor 4-phenylbutyrate (4-PBA), and the inhibitor of autophagy Bafilomycin A1 (Baf A1), respectively, HDMECs were then subjected to H/R treatment. Cell survival and the percentage of ethynyldeoxyuridine-labeled cells in the BTXA pretreatment groups were reduced by the addition of Tg, 4-PBA, and Baf A1. While the expression of GRP78, CHOP, and LC3 was upregulated by Tg and Baf A1, it was downregulated by 4-PBA. The findings showed that ER stress produced by BTXA pretreatment triggers protective autophagy and protects HDMECs from H/R damage. There were no cytoprotective effects from either excessive activation or reduction of ER stress. Our results are consistent with the notion that autophagy and moderate ER stress are critical for cellular longevity and, consequently, functional integrity and may represent a potential therapeutic target.

Advance in topical biomaterials and mechanisms for the intervention of pressure injury

Pressure injuries (PIs) are localized tissue damage resulting from prolonged compression or shear forces on the skin or underlying tissue, or both. Different stages of PIs share common features include intense oxidative stress, abnormal inflammatory response, cell death, and subdued tissue remodeling. Despite various clinical interventions, stage 1 or stage 2 PIs are hard to monitor for the changes of skin or identify from other disease, whereas stage 3 or stage 4 PIs are challenging to heal, painful, expensive to manage, and have a negative impact on quality of life. Here, we review the underlying pathogenesis and the current advances of biochemicals in PIs. We first discuss the crucial events involved in the pathogenesis of PIs and key biochemical pathways lead to wound delay. Then, we examine the recent progress of biomaterials-assisted wound prevention and healing and their prospects.

Effect of Heat Shock Preconditioning on Pressure Injury Prevention via Hsp27 Upregulation in Rat Models

Pressure injury (PI) prevention is a huge industry and involves various interventions. Temperature and moisture are important factors for wound healing; however, the active mechanism by which “moist heat” affects PI prevention has not yet been clarified. Thus, we explored the protective and therapeutic effects of hydrotherapy on PI based on the preconditioning (PC) principle, which might be useful for clinical practice. This study aimed to investigate the preventive mechanisms of heat shock preconditioning on PIs in rat models. The experiment was performed in the basic medical laboratory of Nagano College of Nursing in Japan. Ten rats were divided into two groups, with five rats in each group. Rats in the control group were not bathed. Rats in the preconditioning group (PC group) were bathed with hot tap-water. Bathing was conducted thrice a week. After bathing for 4 weeks, the PI model was constructed on the rats’ dorsal skin. The skin temperature, skin moisture, and area of ulcers were compared between the two groups. In vitro, we investigated the expression of heat shock protein 27 (Hsp27) in 6, 12, and 24 h after the PI model was constructed through Western blot analysis. Ulcers occurred in the control group 24 h after the PI model constructed, wheras the PC group exhibited ulcers after 36 h. The ulcer area was larger in the control group than that in the PC group after 24 h (all p < 0.05). The temperatures of PI wounds in the control group decreased and were lower than those in the PC group after 1, 6, 12, 36, and 48 h (all p < 0.05). However, the skin moisture levels of PI wounds increased in the control group and were higher than those in the PC group at the same time (all p < 0.05). Using Western blot analysis, hydrotherapy preconditioning showed the potential to increase Hsp27 expression after pressure was released (p < 0.05). We determine that heat shock preconditioning had a preventive effect on PIs in rat models, a result that may be associated with their actions in the upregulation of Hsp27.

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.

Prevention Effects of Chain Management on Pressure Ulcers of Hospitalized Patients

The study focused on the preventive effects of the chain management model on pressure ulcers in the operating room. Sqoop big data collection module is used to collect patient information from various hospital information systems in a distributed manner. The data were from the clinical data center of the Zhongshan Hospital Xiamen University General Hospital, and 268 patients were selected as the research subjects. A chain management model is constructed, concerning the preventive measures, the management of each link, the perioperative pressure ulcer management, and the reporting of pressure ulcers. Then, the two groups were compared for the SAS and SDS scores before and after nursing, the pressure ulcer sites, pressure ulcer reporting rate, pressure ulcer staging, and nursing satisfaction. The results show that it is not that more collection modules will lead to better cluster performance and that the execution delay is caused by MapReduce requiring the JAVA virtual machine, and after reaching a certain point, the increase in the number of tasks will slow down the process, and as data size increases, DataNote has an expanded capability to analyze data. After nursing treatment, the SAS and SDS scores of the two groups of patients were significantly lower than before treatment (P < 0.05). The pressure ulcers were mainly distributed in the forehead, mandible, cheeks, front chest, and knees in the two groups, and the difference between the two groups was statistically significant (P < 0.05). The total satisfaction of the observation group was 93.28%, and the total satisfaction of the control group was 92.54%. The patients' satisfaction with the chain management model was higher than that of conventional nursing.

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.

Autologous scalp skin grafting to treat toxic epidermal necrolysis in a patient with a large skin injury: A case report

BACKGROUND

Toxic epidermal necrolysis (TEN) is often associated with skin wounds affecting large areas. Healing of this type of wound is difficult because of pressure, infection and other factors. It can increase the length of hospital stay and result in wound sepsis and even death.

CASE SUMMARY

A 49-year-old woman developed a skin lesion covering 80% of the total body surface area after using a kind of Chinese medicinal ointment on a burn wound on her back; she developed life-threatening wound sepsis and septic shock. Methicillin-resistant Staphylococcus aureus, carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Pseudomonas aeruginosa and other bacteria were cultured from wound tissue, deep venous catheter and blood samples. Imipenem cilastatin sodium, tigecycline and teicoplanin were used for anti-infection therapy. Finally, the patient was transferred to the burn department because of severe wound sepsis. In the burn intensive care unit, pain-free dressing changes and autologous scalp skin grafting were performed to heal the wound in addition to reasonable and effective antibacterial treatment according to microbial susceptibility test results. After three operations within 2 wk, the wound healed and sepsis resolved.

CONCLUSION

TEN patients with large areas of skin injury may develop wound infection and life-threatening wound sepsis. Autologous scalp skin grafting may be beneficial for rapid wound healing and reducing the risk of sepsis in TEN patients, and it leaves no scar at the donor site.

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.

Apelin/APJ signaling suppresses the pressure ulcer formation in cutaneous ischemia-reperfusion injury mouse model

Several studies have demonstrated potential roles for apelin/APJ signaling in the regulation of oxidative stress associated with ischemia-reperfusion (I/R) injury in several organs. Objective was to assess the role of apelin/APJ signaling in the development of pressure ulcers (PUs) formation after cutaneous I/R injury in mice. We identified that cutaneous I/R injury increased the expression of apelin in the skin at I/R site. Administration of apelin significantly inhibited the formation of PUs. The reductions of blood vessels, hypoxic area and apoptosis in I/R site were inhibited by apelin injection. Oxidative stress signals in OKD48 mice and the expressions of oxidative stress related genes in the skin were suppressed by apelin injection. H₂O₂-induced intracellular ROS and apoptosis in endothelial cells and fibroblasts were suppressed by apelin in vitro. Furthermore, MM07, biased agonist of APJ, also significantly suppressed the development of PUs after cutaneous I/R, and the inhibitory effect of MM07 on PUs formation was higher than that in apelin. We conclude that apelin/APJ signaling may inhibit cutaneous I/R injury-induced PUs formation by protecting the reduction of vascularity and tissue damage via suppression of oxidative stress. Exogenous application of apelin or MM07 might have therapeutic potentials against the development of PUs.

Zinc deficiency exacerbates pressure ulcers by increasing oxidative stress and ATP in the skin

BACKGROUND

Zinc deficiency is believed to be a predisposing factor for the development and intractable healing of pressure ulcers (PUs); however, the mechanisms of this association have not been elucidated.

OBJECTIVE

Objective was to elucidate the mechanisms of the formation of severe and prolonged PUs under the zinc deficiency condition.

METHODS

We assessed PUs formation after cutaneous ischemia-reperfusion (I/R) injury in mice fed with a zinc-adequate (ZA) or a zinc-deficient (ZD) diet from 2 weeks before I/R injury. Wound size, vascular damage, apoptotic cells, adenosine triphosphate (ATP) amount, and the number of Langerhans cells (LCs) in I/R area were analyzed. We evaluated the extent of oxidative stress in I/R area in OKD48 mice through bioluminescence detection.

RESULTS

We found that dietary zinc deficiency caused the formation of severe and prolonged PUs in mice. Zinc deficiency increased the vascular disorder, oxidative stress, and apoptosis induced by cutaneous I/R injury. I/R injury-induced oxidative stress signals were significantly higher in ZD OKD48 mice than in ZA OKD48 mice. Additionally, zinc deficiency reduced the number of LCs and increased the amount of ATP in cutaneous I/R-injured skin. Oral supplementation of zinc improved zinc deficiency-associated PUs.

CONCLUSION

Zinc deficiency might increase cutaneous I/R injury-induced vascular damages, oxidative stress, and apoptosis, as well as ATP amount in I/R area due to the loss of LCs. These mechanisms might partly account for zinc deficiency-induced formation of severe and prolonged PUs. Oral supplementation of zinc might be a reasonable therapeutic choice for patients with PUs and zinc deficiency.