Transplantation of human induced pluripotent stem cell derived keratinocytes accelerates deep second-degree burn wound healing

BACKGROUND Current evidence shows that human induced pluripotent stem cells(hiPSCs)can effectively differentiate into keratinocytes(KCs),but its effect on skin burn healing has not been reported.AIM To observe the effects of hiPSCs-derived KCs transplantation on skin burn healing in mice and to preliminarily reveal the underlying mechanisms.METHODS An analysis of differentially expressed genes in burn wounds based on GEO datasets GSE140926,and GSE27186 was established.A differentiation medium containing retinoic acid and bone morphogenetic protein 4 was applied to induce hiPSCs to differentiate into KCs.The expression of KCs marker proteins was detected using immunofluorescence staining.A model of a C57BL/6 mouse with deep cutaneous second-degree burn was created,and then phosphate buffered saline(PBS),hiPSCs-KCs,or hiPSCs-KCs with knockdown of COL7A1 were injected around the wound surface.The wound healing,re-epithelialization,engraftment of hiPSCs-KCs into wounds,proinflammatory factor level,and the NF-κB pathway proteins were assessed by hematoxylin-eosin staining,carboxifluorescein diacetate succinimidyl ester(CFSE)fluorescence staining,enzyme linked immunosorbent assay,and Western blotting on days 3,7,and 14 after the injection,respectively.Moreover,the effects of COL7A1 knockdown on the proliferation and migration of hiPSCs-KCs were confirmed by immunohistochemistry,EdU,Transwell,and damage repair assays.RESULTS HiPSCs-KCs could express the hallmark proteins of KCs.COL7A1 was down-regulated in burn wound tissues and highly expressed in hiPSCs-KCs.Transplantation of hiPSCs-KCs into mice with burn wounds resulted in a significant decrease in wound area,an increase in wound re-epithelialization,a decrease in proinflammatory factors content,and an inhibition of NF-κB pathway activation compared to the PBS group.The in vitro assay showed that COL7A1 knockdown could rescue the inhibition of hiPSCs-KCs proliferation and migration,providing further evidence that COL7A1 speeds up burn wound healing by limiting cell proliferation and migration.CONCLUSION In deep,second-degree burn wounds,COL7A1 can promote KC proliferation and migration while also suppressing the inflammatory response.

Antimicrobial hydrogel with multiple pH-responsiveness for infected burn wound healing

Burns are a common medical problem globally,and wound infection is one of the major causes of inducing related complications.Although antibiotics effectively prevent wound infections,the misuse of antibiotics has created a new problem of superbugs.Herein,we propose a new strategy to obtain pH-responsive antimicrobial P-ZIF(ZIF:zeolitic imidazolate framework)by loading polyhexamethylenebiguanide(PHMB)into the framework of ZIF-8 nanoparticles.This will enable PHMB to be released in the weak acid environment of an infected wound.To address burn infections,P-ZIF nanoparticles were loaded into a hydrogel system made of sodium alginate(SA)and 3-aminophenylboronic acid modified human-like collagen(H-A)through borate ester bonds.The resulting H-A/SA/P-ZIF(HASPZ)hydrogel dressing not only possesses antibacterial and wound healing properties but also has dual pH responsiveness to prevent the overuse of medication while effectively treat deep second-degree burns.Therefore,P-ZIF nanoparticles and the corresponding HASPZ hydrogel dressing are considered of significant importance in antimicrobial,drug delivery,and wound repair.

Macrophage metabolism reprogramming EGCG-Cu coordination capsules delivered in polyzwitterionic hydrogel for burn wound healing and regeneration

Excessive reactive oxygen species(ROS)at severe burn injury sites may promote metabolic reprogramming of macrophages to induce a deteriorative and uncontrolled inflammation cycle,leading to delayed wound healing and regeneration.Here,a novel bioactive,anti-fouling,flexible polyzwitterionic hydrogel encapsulated with epigallocatechin gallate(EGCG)-copper(Cu)capsules(termed as EGCG-Cu@CBgel)is engineered for burn wound management,which is dedicated to synergistically exerting ROS-scavenging,immune metabolic regulation and pro-angiogenic effects.EGCG-Cu@CBgel can scavenge ROS to normalize intracellular redox homeostasis,effectively relieving oxidative damages and blocking proinflammatory signal transduction.Importantly,EGCG-Cu can inhibit the activity of hexokinase and phosphofructokinase,alleviate accumulation of pyruvate and convert it to acetyl coenzyme A(CoA),whereby inhibits glycolysis and normalizes tricarboxylic acid(TCA)cycle.Additionally,metabolic reprogramming of macrophages by EGCG-Cu downregulates M1-type polarization and the expression of proinflammatory cytokines both in vitro and in vivo.Meanwhile,copper ions(Cu^(2+))released from the hydrogel facilitate angiogenesis.EGCG-Cu@CBgel significantly accelerates the healing of severe burn wound via promoting wound closure,weakening tissue-damaging inflammatory responses and enhancing the remodeling of pathological structure.Overall,this study demonstrates the great potential of bioactive hydrogel dressing in treating burn wounds without unnecessary secondary damage to newly formed skin,and highlights the importance of immunometabolism modulation in tissue repair and regeneration.

Design of a biofluid-absorbing bioactive sandwich-structured Zn-Si bioceramic composite wound dressing for hair follicle regeneration and skin burn wound healing

The deep burn skin injures usually severely damage the dermis with the loss of hair follicle loss,which are difficult to regenerate.Furthermore,severe burns often accompanied with large amount of wound exudates making the wound moist,easily infected,and difficult to heal.Therefore,it is of great clinical significance to develop wound dressings to remove wound exudates and promote hair follicle regeneration.In this study,a sandwich-structured wound dressing(SWD)with Janus membrane property was fabricated by hot compression molding using hydrophilic zinc silicate bioceramics(Hardystonite,ZnCS)and hydrophobic polylactic acid(PLA).This unique organic/inorganic Janus membrane structure revealed excellent exudate absorption property and effectively created a dry wound environment.Meanwhile,the incorporation of ZnCS bioceramic particles endowed the dressing with the bioactivity to promote hair follicle regeneration and wound healing through the release of Zn^(2+)and SiO^(2-)_(3)ions,and this bioactivity of the wound dressing is mainly attributed to the synergistic effect of Zn^(2+)and SiO^(2-)_(3)to promote the recruitment,viability,and differentiation of hair follicle cells.Our study demonstrates that the utilization of the Janus membrane and synergistic effect of different type bioactive ions are effective approaches for the design of wound dressings for burn wound healing.

Obstruction of the formation of granulation tissue leads to delayed wound healing after scald burn injury in mice

Background:Delayed wound healing remains a common but challenging problem in patients with acute or chronic wound following accidental scald burn injury.However,the systematic and detailed evaluation of the scald burn injury,including second-degree deep scald(SDDS)and thirddegree scald(TDS),is still unclear.The present study aims to analyze the wound-healing speed,the formation of granulation tissue,and the healing quality after cutaneous damage.Methods:In order to assess SDDS and TDS,the models of SDDS and TDS were established using a scald instrument in C57BL/6 mice.Furthermore,an excisional wound was administered on the dorsal surface in mice(Cut group).The wound-healing rate was first analyzed at days 0,3,5,7,15 and 27,with the Cut group as a control.Then,on the full-thickness wounds,hematoxylin and eosin(H&E)staining,Masson staining,Sirius red staining,Victoria blue staining and immunohistochemistry were performed to examine re-epithelialization,the formation of granulation tissue,vascularization,inflammatory infiltration and the healing quality at different time points in the Cut,SDDS and TDS groups.Results:The presented data revealed that the wound-healing rate was higher in the Cut group,when compared with the SDDS and TDS groups.H&E staining showed that re-epithelialization,formation of granulation tissue and inflammatory infiltration were greater in the Cut group,when compared with the SDDS and TDS groups.Immunohistochemistry revealed that the number of CD31,vascular endothelial growth factor A,transforming growth factor-βandα-smooth muscle actin reached preferential peak in the Cut group,when compared with other groups.In addition,Masson staining,Sirius red staining,Victoria blue staining,Gordon-Sweets staining and stress analysis indicated that the ratio of collagen I to III,reticular fibers,failure stress,Young’s modulus and failure length in the SDDS group were similar to those in the normal group,suggesting that healing quality was better in the SDDS group,when compared with the Cut and TDS groups.Conclusion:Overall,the investigators first administered a comprehensive analysis in the Cut,SDDS and TDS groups through in vivo experiments,which further proved that the obstacle of the formation of granulation tissue leads to delayed wound healing after scald burn injury in mice.

Doseeffect of dietary Larginine supplementation on burn woundhealing in rats

Objective To investigate the dose effect of dietary L arginine supplementation on burn wound healing in rats Methods 218 Sprague Dawley rats (weighing 200-250?g) were subjected to 10% deep partial thickness scald burns and were randomized into six groups Groups A, B, C, D, E and F received 800, 400, 200, 100, 50 and 0?mg·kg -1 ·d -1 L arginine in the form of L arginine solution, and 0, 727, 1090, 1272, 1364, and 1454?mg·kg -1 ·d 1 glycine, respectively Each solution was isonitrogenous The times of completing re epithelization were recorded The contents of hydroxyproline (OHP) in burn wound area (index of reparative collagen synthesis) and the ratios of type Ⅰ and type Ⅲ collagen were examined in all groups Results The times of completing re epithelization (day) in groups A, B, C, D, E, and F were 24 9±1 95, 22 5±2 0, 20 2±2 4, 23 5±2 6, 23 8±3 5, and 24 7±2 3, respectively The contents of hydroxyproline in groups B, C and D were higher than in groups A, E and F on PBD 7, 10 and 14 The ratios of typeⅠ and type Ⅲ collagen in groups B, C and D were lower than in groups A, E and F Conclusion Oral dietary L arginine supplementation from 100?mg·kg -1 ·d -1 to 400?mg·kg -1 ·d -1 shortened the times of re epithelization, increased amounts of hydroxyproline, and accelerated the synthesis of reparative collagen in burn rats