Extensive tissue and organ defects caused by major trauma and burns are common problems in clinical practice. Recombinant human collagen biomaterials, with advantages including impeccable biocompatibility, customization, stable amino acid sequence, low immunogenicity, and inherent biodegradation, have been widely used in the field of tissue engineering and have broad clinical application prospects. This paper briefly summarizes the design and preparation methods, processing techniques of recombinant human collagen biomaterials and their application in the field of tissue engineering, as well as the latest research advances.

Extensive tissue and organ defects caused by major trauma and burns are common problems in clinical practice. Recombinant human collagen biomaterials, with advantages including impeccable biocompatibility, customization, stable amino acid sequence, low immunogenicity, and inherent biodegradation, have been widely used in the field of tissue engineering and have broad clinical application prospects. This paper briefly summarizes the design and preparation methods, processing techniques of recombinant human collagen biomaterials and their application in the field of tissue engineering, as well as the latest research advances.

Wound microenvironment is directly related to the speed and quality of wound healing, and it is composed of various physical, chemical, and biological factors, and these factors are in a dynamic balance under normal conditions. In order to understand the effects of various physical, chemical, and biological factors on wound healing and to create microenvironment that can promote wound healing, this paper reviewed several wound external microenvironment factors including temperature, humidity, pH values, oxygen, microorganism, and biomechanics.

Objective:To explore the changes in resting energy expenditure (REE) values in patients with severe burns under different metabolic stages and the selection of the optimal calculation formula.Methods:This study was a retrospective and observational study. From April 2020 to December 2023, 40 patients (32 males and 8 females, aged (54±17) years) with severe burns meeting inclusion criteria were treated in the Second Affiliated Hospital of Zhejiang University School of Medicine. After admission, the patients were given routine clinical treatments such as sedation and analgesia, debridement, and skin grafting. At 3, 5, 7, 9, 11, 14 days after injury and every 7 days thereafter, the REE values (i.e., REE measured values) were measured by indirect calorimetry in patients with severe burns who met the measurement conditions till the patients recovered or died. On the day the patient's REE was measured, Milner, Hangang, the Third Military Medical University, Carlson, and Peng Xi team's linear formula were used respectively to calculate the REE value (i.e., REE formula values). The post-injury time to measure REE in patients was calculated, and the clinical characteristics of patients in acute inhibition, hypermetabolic, metabolic balance, and metabolic remodeling phases were compared. The REE measured values and the difference between the REE formula values and the REE measured values of patients under the 4 different metabolic phases were calculated.Compared with the REE measured values, the 10% accuracy rate and 20% accuracy rate were calculated to evaluate the accuracy of the REE formula values. The absolute percentage error (APE) of the REE formula values were calculated to evaluate the deviation. The metabolic formula (i.e., the optimal calculation formula) that was closest to the measured REE values was screened out, and further exploration was conducted to identify the key factors that affected the accuracy of the optimal calculation formula under different metabolic phases.Results:The post-injury time to measure REE in patients with severe burns was (40±19) days. Comparisons showed that under the 4 different metabolic phases, patients in the metabolic remodeling phase had the highest age, height, weight, body mass index, total body surface area. Age in the metabolic remodeling phase was significantly higher than that in the acute inhibition and hypermetabolic phases (with t values of -3.02 and -4.20, respectively, with all P values <0.05), weight was significantly higher than that in the hypermetabolic and metabolic balance phases (with t values of -1.97 and -2.61, respectively, with all P values <0.05), body mass index was significantly higher than that in the hypermetabolic phase ( t=-2.90, P<0.05), and total body surface area was significantly larger than that in the hypermetabolic and metabolic balance phases (with t values of -2.02 and -2.27, respectively, with all P values <0.05). There was no significant change in patients' REE measured values under the 4 different metabolic stages ( P>0.05). Except for the Peng Xi team's linear formula ( P>0.05), the difference between REE measured values and REE formula values calculated by using Milner, Hangang, the Third Military Medical University, and Carlson formulas respectively was statistically significant under different metabolic stages (with H values of 14.50, 27.15, and 37.26, respectively, F=11.80, P<0.05). Comprehensive analysis of 10% accuracy, 20% accuracy, and APE showed that in the acute inhibition phase, the REE formula values calculated by Peng Xi team's linear formula was closest to REE measured values, and the APE of the REE formula values calculated by Peng Xi team's linear formula was significantly lower than those calculated by Milner formula, Hangang formula, the Third Military Medical University formula, and Carlson formula (with t values of 9.00, -2.10, 5.95, and 6.68, respectively, with all P values <0.05). In the hypermetabolic phase, the REE formula values calculated by Hangang formula were closest to REE measured values, with significantly lower APE of the REE formula values calculated by Hangang formula than those calculated by using Milner formula, the Third Military Medical University formula, Carlson formula, and Peng Xi team's linear formula (with t values of 10.20, 10.33, 10.65, and 5.87, respectively, with all P values <0.05). In the metabolic balance phase, the REE formula values calculated by Hangang formula were again closest to REE measured values, with significantly lower APE of the REE formula values calculated by Hangang formula than those calculated by Milner formula, the Third Military Medical University formula, and Carlson formula (with t values of 7.11, 8.52, and 8.60, respectively, with all P values <0.05). In the metabolic remodeling phase, the REE formula values calculated by the Third Military Medical University were closest to REE measured values, with significantly lower APE of the REE formula values calculated by the Third Military Medical University formula than those calculated by Milner formula, Hangang formula, and Carlson formula (with t values of 5.12, 2.45, and 6.26, respectively, with all P values <0.05). No significant key factors affected the accuracy of the Peng Xi team's linear formula in the acute inhibition phase ( P>0.05). In the hypermetabolic phase, total burn area was a key factor affecting the accuracy of Hangang formula (with odds ratio of 1.00, with 95% confidence interval of 1.00-1.10, P<0.05). In the metabolic balance phase, post-injury days was a key factor affecting the accuracy of Hangang formula (with odds ratio of 1.30, with 95% confidence interval of 1.10-1.40, P<0.05). In the metabolic remodeling phase, no significant key factors affected the accuracy of the Third Military Medical University formula ( P>0.05). Conclusions:When calculating REE values in patients with severe burns, it is recommended to use the Peng Xi team's linear formula during the acute inhibition phase, the Hangang formula during the hypermetabolic and metabolic balance phases, and the Third Military Medical University formula during the metabolic remodeling phase. Additionally, it is crucial to ensure the accuracy of key factors affecting the optimal calculation formula in the hypermetabolic and metabolic balance phases.

The human immune system plays a key role in maintaining tissue homeostasis and disease progression. The development of biomaterials that can regulate the innate immune system and adapt to the immune system has great application prospects in the field of tissue engineering. This paper discusses how to design the surface interface topographies or the physicochemical properties of biomaterials, to regulate the fate of macrophages, such as activation, polarization, adhesion, migration, proliferation, and secretion. At the same time, the application of these biomaterials with immunoregulation function in the field of wound healing is discussed. In addition, this paper also put forward the limitations of biomaterials in immunoregulation applications and prospected the future development directions.

Objective:To explore forecast indicators for the prognosis of sepsis in adult extremely severe burn patients.Methods:Case data of adults with extremely severe burns combined with sepsis admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2017 to December 2021 were retrospectively collected. According to the prognosis, all patients were divided into a death group and a survival group. The general conditions of the two groups were compared. The clinical symptoms, vital signs, platelet count (PLT), white blood cell count (WBC), neutrophil ratio, procalcitonin (PCT), blood sodium, blood glucose, hemoglobin and albumin levels at diagnosis of sepsis were also compared between the two groups. The independent sample t test, Mann?Whitney U test, or Fisher's exact probability test was used for group comparison. Variables with statistical significance in univariate analysis were included in the Cox regression model for multivariate analysis to assess the effect of each index on the outcome of extremely severe burn patients with sepsis. The predictive value of each index for sepsis outcome was analyzed by the receiver operating characteristic curve (ROC). Results:A total of 60 patients with particularly severe burn sepsis were selected, including 41 males and 19 females aged 18 to 84 years. The diagnosis time of sepsis was 14 (7, 24) days after injury. There were 29 patients in the death group and 31 patients in the survival group, and the mortality rate was 48.3%. Compared with the survival group, PLT and hemoglobin levels in the death group decreased significantly (both P<0.05), and PCT and blood sodium levels increased significantly (both P<0.05), while the other indicators did not change significantly (all P>0.05). The results of multivariate Cox regression analysis showed that hemoglobin ( HR=0.936, 95% CI: 0.935-0.991) and serum sodium levels ( HR=1.031, 95% CI: 1.010-1.052) at the time of sepsis diagnosis were independent risk factors affecting the prognosis of sepsis in extra-severe burn patients (both P<0.05). ROC curve analysis showed that the AUCs of hemoglobin, blood sodium and PCT for predicting the prognosis of extremely severe burn patients with sepsis were 0.747, 0.811 and 0.690, respectively (all P<0.05). The cut-off value of hemoglobin for predicting prognosis was 77 g/L, with a sensitivity of 69.0% and specificity of 74.2%. The cut-off value of blood sodium for predicting prognosis was 138 mmol/L, with a sensitivity of 89.7% and specificity of 61.3%. The cut-off value of PCT was 3.51 μg/L, with a sensitivity of 65.5% and specificity of 74.2%. Conclusions:Hemoglobin, blood sodium and PCT may be predictors of outcome in extremely severe burn patients with sepsis.

Hidradenitis suppurative is a chronic, refractory and recurrent dermatological disease. The disease should be managed by targeted surgical intervention on the basis of medical treatment. Currently, the surgical treatment methods include local treatments like incision and drainage, unroofing, laser therapy, intense pulsed light therapy, photodynamic therapy, as well as complete lesion resection such as skin-tissue saving excision with electrosurgical peeling and extended excision. The clearance range, therapeutic effect, postoperative complications, and recurrence risk vary among the different treatment methods. Local treatments cause less damage, but have high recurrence rates, and are mainly for mild to moderate hidradenitis suppurative patients. Complete lesion resections have relatively low recurrence rates, but may bring more surgical injuries, and postoperative reconstructions are needed, which are mainly for moderate to severe hidradenitis suppurative patients. In this article, the surgical treatment principles and various surgical treatment methods of hidradenitis suppurative are reviewed, to provide a reference for the diagnosis and treatment of this disease in clinical practice.
Humans ; Hidradenitis Suppurativa/complications* ; Hidradenitis/complications* ; Drainage ; Postoperative Complications ; Skin

Foreign body reactions induced by macrophages often cause delay or failure of wound healing in the application of tissue engineering scaffolds. This study explores the application of nanosilver (NAg) to reduce foreign body reactions during scaffold transplantation. An NAg hybrid collagen-chitosan scaffold (NAg-CCS) was prepared using the freeze-drying method. The NAg-CCS was implanted on the back of rats to evaluate the effects on foreign body reactions. Skin tissue samples were collected for histological and immunological evaluation at variable intervals. Miniature pigs were used to assess the effects of NAg on skin wound healing. The wounds were photographed, and tissue samples were collected for molecular biological analysis at different time points post-transplantation. NAg-CCS has a porous structure and the results showed that it could release NAg constantly for two weeks. The NAg-CCS group rarely developed a foreign body reaction, while the blank-CCS group showed granulomas or necrosis in the subcutaneous grafting experiment. Both matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were reduced significantly in the NAg-CCS group. The NAg-CCS group had higher interleukin (IL)-10 and lower IL-6 than the blank CCS group. In the wound healing study, M1 macrophage activation and inflammatory-related proteins (inducible nitric oxide synthase (iNOS), IL-6, and interferon-‍γ (IFN-‍γ)) were inhibited by NAg. In contrast, M2 macrophage activation and proinflammatory proteins (arginase-1, major histocompatibility complex-II (MHC-II), and found in inflammatory zone-1 (FIZZ-1)) were promoted, and this was responsible for suppressing the foreign body responses and accelerating wound healing. In conclusion, dermal scaffolds containing NAg suppressed the foreign body reaction by regulating macrophages and the expression of inflammatory cytokines, thereby promoting wound healing.
Animals ; Rats ; Swine ; Interleukin-6 ; Macrophage Activation ; Tissue Inhibitor of Metalloproteinase-1 ; Wound Healing ; Foreign-Body Reaction ; Foreign Bodies ; Chitosan

Although the treatment of patients with burns combined with inhalation injury has achieved great success, from the perspective of epidemiology, inhalation injury is still the most common cause of death in mass burns. Such patients often suffered burns of large total body surface area, which is difficult to treat, with airway management as one of the core links. Physical airway clearance technique (ACT) acts on a patient's respiratory system by physical means, to discharge secretions and foreign bodies in the airway, achieve airway clearance, and improve gas exchange. In addition, the technique can prevent or alleviate many complications, thereby improving the clinical outcome of patients with inhalation injury. This article reviews the application of physical ACT in the field of inhalation injury, and to provide decision-making basis for clinical medical staff to choose physical ACT corresponding to the patient's condition.

Objective:To explore the epidemiological characteristics and risk factors of sepsis development and death in patients with extremely severe burns.Methods:A retrospective case series study was conducted. From January 2017 to December 2021, 135 patients with extremely severe burns who met the inclusion criteria were admitted to the Department of Burn and Wound Repair of the Second Affiliated Hospital of Zhejiang University School of Medicine, including 100 males and 35 females, aged 18-84 years. The incidence and diagnosis time of sepsis, the rate of positive microbial culture of blood samples (hereinafter referred to as positive blood culture), and the mortality rate of all patients, as well as the incidence of sepsis and the pathogen of infection in patients with positive blood culture were recorded (statistically analyzed with chi-square test or Fisher's exact probability test). According to the occurrence of sepsis, all patients were divided into sepsis group (58 cases) and non-sepsis group (77 cases), and the gender, age, body mass index, history of hypertension, history of diabetes, combination of inhalation injury, burn site, burn type, total burn area, and combined injury of patients were compared between the two groups. According to the outcome, all patients were divided into death group (37 cases) and survival group (98 cases), and the aforementioned data grouped according to sepsis as well as the stability of shock period and the combination of sepsis of patients were compared between the two groups. The aforementioned data between two groups were statistically analyzed with univariate analysis of independent sample t test, Wilcoxon rank-sum test, Mann-Whitney U test, chi-square test, or Fisher's exact probability test. Factors with P<0.1 were selected for multivariate logistic regression analysis to screen independent risk factors of sepsis and death in patients with extremely severe burns. Results:Among all patients, the incidence of sepsis was 42.96% (58/135), the diagnosis time of sepsis was 14 (7, 24) d after injury, the positive blood culture rate was 62.22% (84/135), and the mortality rate was 27.41% (37/135). The incidence of sepsis of patients with positive blood culture was 69.05% (58/84). The top 5 pathogenic bacteria in the detection rate of septic patients with positive blood culture were Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterobacter cloacae, ranking from high to low, and the proportion of Acinetobacter baumannii infected was significantly higher than that of non-septic patients with positive blood culture ( χ2=7.49, P<0.05). Compared with those in non-sepsis group, the proportion of combination of inhalation injury, the proportion of perineal burns, and the total burn area of patients in sepsis group increased significantly (with χ2 values of 11.08 and 17.47, respectively, Z=5.68, P<0.05), while the other indicators did not change significantly ( P>0.05). Multivariate logistic regression analysis showed that combination of inhalation injury, total burn area ≥80% total body surface area (TBSA), and perineal burns were independent risk factors for patients with extremely severe burns developing sepsis (with odds ratios of 3.15, 7.24, and 3.24, respectively, with 95% confidence intervals of 1.07 to 9.29, 1.79 to 29.34, and 1.21 to 8.68, respectively, P<0.05). Compared with those in survival group, the proportion of combination of inhalation injury, the proportion of perineal burns, and the proportion of combination of sepsis (with χ2 values of 6.55, 11.64, and 22.26, respectively, P values all <0.05), total burn area ( Z=4.25, P<0.05), and proportion of instability of shock period ( P<0.05) of patients in death group all increased significantly, while the other indicators did not change significantly ( P>0.05). Multivariate logistic regression analysis showed that the instability of shock period and combination of sepsis were independent risk factors for death of patients with extremely severe burns (with odds ratios of 4.87 and 3.45, respectively, with 95% confidence intervals of 1.21 to 19.57 and 1.28 to 9.33, respectively, P<0.05). Conclusions:Patients with extremely severe burns have a high incidence of sepsis and a high mortality rate. The peak period of sepsis onset is 2 weeks after injury, with Acinetobacter baumannii as the most prominent infectious pathogen. Combination of inhalation injury, total burn area ≥80% TBSA, and perineal burns are independent risk factors for extremely severe burn patients complicated with sepsis, and combination of sepsis and instability of shock period are independent risk factors for death of patients with extremely severe burns.