Omental coating attenuates implant-induced foreign body reaction in rats.

The objective of this study is to clarify whether the omental coating can effectively attenuate foreign body reaction (FBR) induced by implanted materials. Male Sprague-Dawley rats were injected with polydextran particle slurry intraperitoneally to activate the omentum. 7 days later, polyether polyurethane sponge discs were implanted subcutaneously on each side of the rat's back as the foreign implants to induce FBR. The next day, omental transposition were performed. The disc on the left side of each rat's back was wrapped with omental flap (omental group); the disc on the right side was untreated (control group). All discs were removed 21 days after implantation and assessed by determining the components of the fibrovascular tissue (angiogenesis, inflammation, foreign body giant cells (FBGCs) aggregation and fibrogenesis). In implants in omental group, micro vessel density (MVD), Hemoglobin (Hb) content and VEGF levels (pro-angiogenic cytokine) were increased when compared with implants from control group. Inflammatory parameters (IL-1ß; macrophage accumulation-NAG activity; neutrophil accumulation- MPO levels) were decreased in implants after omental coating. Also, collagen deposition, fibrous capsule thickness, and FBGCs decreased in implants from omental group. However, intra-implant levels of TNF-α and TGF-ß1 were not different after omental coating. Our findings showed for the first time that the omental coating around the implants attenuate the adverse FBR, it may be critical in developing new strategies to control FBR and improve the function and performance of the implanted materials.

The burden of skin and subcutaneous diseases: findings from the global burden of disease study 2019.

Background: The small number of existing integrative studies on the global distribution and burden of all types of skin and subcutaneous diseases hinders relevant comparisons. Objective: This study aimed to determine the latest distribution, epidemiological differences, and factors potentially influencing each skin and subcutaneous disease and the policy implications. Methods: Data on the skin and subcutaneous diseases were obtained from the Global Burden of Disease Study 2019. The incidence, disability-adjusted life years (DALYs), and deaths due to skin and subcutaneous diseases in 204 countries and regions from 1990 to 2019 were analyzed and stratified by sex, age, geographical location, and sociodemographic index (SDI). The annual age-standardized rate of change in the incidence was obtained to evaluate temporal trends. Results: Of 4,859,267,654 (95% uncertainty interval [UI], 4,680,693,440-5,060,498,767) new skin and subcutaneous disease cases that were identified, most were fungal (34.0%) and bacterial (23.0%) skin diseases, which accounted for 98,522 (95% UI 75,116-123,949) deaths. The burden of skin and subcutaneous diseases measured in DALYs was 42,883,695.48 (95%UI, 28,626,691.71-63,438,210.22) in 2019, 5.26% of which were years of life lost, and 94.74% of which were years lived with disability. The highest number of new cases and deaths from skin and subcutaneous diseases was in South Asia. Globally, most new cases were in the 0-4-year age group, with skin and subcutaneous disease incidence slightly higher in men than in women. Conclusion: Fungal infections are major contributors to skin and subcutaneous diseases worldwide. Low-middle SDI states had the highest burden of skin and subcutaneous diseases, and this burden has increased globally. Targeted and effective management strategies based on the distribution characteristics of each country are, thus, required to reduce the burden of skin and subcutaneous diseases.

Single-cell analysis reveals melanocytes may promote inflammation in chronic wounds through cathepsin G.

During acute wound (AW) healing, a series of proper communications will occur between different epidermal cells at precise temporal stages to restore the integrity of the skin. However, it is still unclear what variation happened in epidermal cell interaction in the chronic wound environment. To provide new insights into chronic wound healing, we reconstructed the variations in the epidermal cell-cell communication network that occur in chronic wound healing via single-cell RNA-seq (scRNA-seq) data analysis. We found that the intricate cellular and molecular interactions increased in pressure ulcer (PU) compared to AW, especially the PARs signaling pathways were significantly upregulated. It shows that the PARs signaling pathways' main source was melanocytes and the CTSG-F2RL1 ligand-receptor pairs were its main contributor. Cathepsin G (CatG or CTSG) is a serine protease mainly with trypsin- and chymotrypsin-like specificity. It is synthesized and secreted by some immune or non-immune cells. Whereas, it has not been reported that melanocytes can synthesize and secrete the CTSG. F2R Like Trypsin Receptor 1 (F2RL1) is a member of proteinase-activated receptors (PARs) that are irreversibly activated by proteolytic cleavage and its stimulation can promote inflammation and inflammatory cell infiltration. In this study, we found that melanocytes increased in pressure ulcers, melanocytes can synthesize and secrete the CTSG and may promote inflammation in chronic wounds through CTSG-F2RL1 pairs, which may be a novel potential target and a therapeutic strategy in the treatment of chronic wounds.

[Effect of deep dermal tissue dislocation injury on skin fibrosis in pig].

Objective: To explore the effect of deep dermal tissue dislocation injury on skin fibrosis in pig, in order to provide some theoretical basis for burn scar treatment. Methods: The experimental research method was applied. Six 2-month-old female Duroc pigs were taken. Fifteen operative areas on the right dorsum of pigs on which medium-thick skin grafts and deep dermal tissue slices were cut and re-implanted were included into dermal in situ reimplantation group, and fifteen operative areas on the left dorsum of pigs on which medium-thick skin grafts and deep dermal tissue slices were cut and the deep dermal tissue slice was placed under the fat layer were included into the dermal dislocation group. The hair growth in the operative areas on post-injury day (PID) 7, 14, and 21 and the cross-sectional structure on PID 14 were observed in the two groups. On PID 7, 14, and 21, the skin thickness (the distance from the epidermis to the upper edge of the fat), the dermal thickness (the distance from the lower edge of the epidermis to the upper edge of the fat, excluding the fibrotic tissue thickness between the dermis and the fat), and the fibrosis tissue thickness of the dermis-fat interface (from the lower edge of the deep dermis to the upper edge of the fat in dermal in situ reimplantation group and from the lower edge of the superficial dermis to the upper edge of the fat in dermal dislocation group) in the operative areas were measured and compared between the two groups; the fibrotic tissue thickness at the dermal cutting interface (from the lower edge of the superficial dermis to the upper edge of the deep dermis) in the operative areas in dermal in situ reimplantation group was measured and compared with the fibrotic tissue thickness at the dermal-fat interface. Sirius red staining was performed to observe and compare the type Ⅰ and Ⅲ collagen content in the dermal-fat interface in the operative areas between the 2 groups and between the dermal cutting interface and dermal-fat interface in the operative areas in dermal in situ reimplantation group. Immunohistochemical staining was performed to observe the positive expressions of proliferating cell nuclear antigen (PCNA), transforming growth factor ß1 (TGF-ß1), fibroblast growth factor 2 (FGF-2), and hepatocyte growth factor (HGF) in the operative areas in the two groups. The sample number was 6. Data were statistically analyzed with independent sample t test. Results: On PID 7, 14, and 21, the hairs in the operative areas in dermal in situ reimplantation group were denser than those in dermal dislocation group. On PID 14, the skin cross section in the operative areas in dermal dislocation group showed a "sandwich"-like structure, while the skin cross section in the operative areas in dermal in situ reimplantation group had normal structure. On PID 7, 14, and 21, the skin thickness in the operative areas in dermal dislocation group was (4 234±186), (4 688±360), and (4 548±360) µm, respectively, which was close to (4 425±156), (4 714±141), and (4 310±473) µm in dermal in situ reimplantation group (P>0.05); the dermal thickness in the operative areas in dermal dislocation group was significantly thinner than that in dermal in situ reimplantation group (with t values of -9.73, -15.85, and -15.41, respectively, P<0.01); the fibrotic tissue thickness at the dermal-fat interface in the operative areas in dermal dislocation group was significantly thicker than that in dermal in situ reimplantation group (with t values of 14.48, 20.58, and 15.67, respectively, P<0.01); there was no statistically significant difference between the fibrotic tissue thickness at the dermal-fat interface and the dermal cutting interface in the operative areas in dermal in situ reimplantation group (P>0.05). On PID 7, 14, 21, the type Ⅲ collagen content in the dermal-fat interface in the operative areas in dermal dislocation group was increased significantly compared with that in dermal in situ replantation group (with t values of 2.65, 0.61, and 7.39, respectively, P<0.05 or P<0.01), whereas there were no statistically significant differences in the type Ⅰ collagen content at the dermal-fat interface in the operative areas between the 2 groups (P>0.05) and the type Ⅰ and Ⅲ collagen content between the dermal-fat interface and the dermal cutting interface in the operative areas in dermal in situ reimplantation group (P>0.05). On PID 7, 14, and 21, PCNA, TGF-ß1, FGF-2, and HGF were positively expressed in the superficial dermis and adipose tissue in the operative areas in dermal dislocation group, while PCNA, TGF-ß1, FGF-2, and HGF were positively expressed in the superficial dermis, deep dermis, and adipose tissue in the operative areas in dermal in situ reimplantation group. Conclusions: Inadequate intrinsic thickness of dermal tissue is the key factor causing fibrosis, and the biological purpose of fibrosis is to "compensate" the intrinsic thickness of the skin. Besides, adipose tissue may also be an important component of fibrotic skin repair.

Prevalence and prognosis of hard-to-heal wounds with comorbidities in China.

OBJECTIVE: Regular retrospective analysis is necessary for potential improvement in clinical practice for the treatment of hard-to-heal wounds. Comorbidities and outcomes have demonstrated spatial and temporal diversity, emphasising the importance of updates in epidemiology. The complexity of healing hard-to-heal wounds has long been known, and so we sought evidence-based improvement on the current principles of treatment. METHOD: Demographic and clinical information of patients from the WoundCareLog database was collected. Patients who met the inclusion criteria and completed follow-up after treatment were included. Comorbidities were diagnosed and classified into eight categories based on ICD-10. We compared the demographic and aetiological characteristics between patients with and without comorbidities by t-test and Chi-squared test. The impact of comorbidities on wound healing were evaluated with a multivariate Cox model. RESULTS: A total of 2163 patients met the inclusion criteria and were enrolled, of whom 37.0% were aged 61-80 years, 36.0% were aged 41-60 years and 60.8% were male. The lower extremities and buttocks were the most commonly affected areas with hard-to-heal wounds. Non-traumatic wounds accounted for 66.6% of cases, and infection, pressure and diabetes were the most common causes. Paralysis and diabetes were the most important factors which led to a prolonged healing process and inferior clinical outcomes. CONCLUSION: Comorbidities of hard-to-heal wounds were treated as separate contributors and their weighted effect on outcome was calculated through correlation analysis. Paralysis and diabetes were the most unfavourable comorbidities affecting the treatment of non-traumatic hard-to-heal wounds. Our study highlighted the priority of comorbidity treatment through data-driven approaches. It provides potential value in developing better public health strategies and preventive medicine.

The epidemiological characteristic and trends of burns globally.

BACKGROUND: Burns is a type of injury, caused by unintentional exposure to substances of high temperature, including hot liquid, solid, and objects radiating heat energy, placing a high burden not only on patients' families but also on national healthcare systems globally. It is difficult for policymakers and clinicians to formulate targeted management strategies for burns because data on current epidemiological patterns worldwide are lacking. METHODS: Data on burns were obtained from the Global Burden of Disease (GBD) 2019 Study. The incidence, disability-adjusted life years (DALYs), and deaths of burns in 204 countries and regions from 1990 to 2019 were calculated and stratified by sex, age, geographical location, and sociodemographic index (SDI). The estimated annual percentage change (EAPC) of incidence, DALYs, and deaths was calculated to evaluate the temporal trends. All analyses were performed using R software, version 4.1.1, with 2-sided P-values < .05 indicating a statistically significant difference. RESULTS: A total of 8,378,122 new cases (95% UI, 6,531,887-10,363,109cases) of burns were identified globally in 2019, which is almost evenly split between men and women, and most of the new cases were concentrated in the 10-19-year age group. Besides, burns account for 111,292 deaths (95% UI, 132,392-88,188) globally in 2019, most of which were concentrated in those aged 1-4 years. The burden of burns measured in DALYs was 7,460,448.65 (95% UI, 5,794,505.89-9,478,717.81) in 2019, of which 67% and 33% could be attributed to YLLs and YLDs, respectively. The EAPC of incidence, DALYs, and deaths were negative, the age-standardized rate (ASR) of incidence, DALYs, and deaths were considered to be decreasing in most of the regions, and the EAPCs were negatively correlated with SDI levels, universal health coverage (UHC), and gross domestic product (GDP). CONCLUSION: Globally, the age-standardized rates of burn incidence, DALYs, and mortality, as well as the number of burn DALYs and death cases will continuously decrease, but the number of new burn cases has an increasing tendency globally. In addition, the EAPCs of burns in incidence, DALYs, and deaths indicated that the burden of burns was considered to be decreasing in most of the regions. And from the relationship of EAPCs with SDI, UHC index, and GDP, indicate that prevention burns not only depend on health spending per capita but also depend on the education level per capita and healthcare system performance, but it does not mean higher health spending corresponds to higher UHC index, which needs high efficiency of translating health spending into individuals health gains.

CT-Angiography-Based Outcome Prediction on Diabetic Foot Ulcer Patients: A Statistical Learning Approach.

The purpose of our study is to predict the occurrence and prognosis of diabetic foot ulcers (DFUs) by clinical and lower extremity computed tomography angiography (CTA) data of patients using the artificial neural networks (ANN) model. DFU is a common complication of diabetes that severely affects the quality of life of patients, leading to amputation and even death. There are a lack of valid predictive techniques for the prognosis of DFU. In clinical practice, the use of scales alone has a large subjective component, leading to significant bias and heterogeneity. Currently, there is a lack of evidence-based support for patients to develop clinical strategies before reaching end-stage outcomes. The present study provides a novel technical tool for predicting the prognosis of DFU. After screening the data, 203 patients with diabetic foot ulcers (DFUs) were analyzed and divided into two subgroups based on their Wagner Score (138 patients in the low Wagner Score group and 65 patients in the high Wagner Score group). Based on clinical and lower extremity CTA data, 10 predictive factors were selected for inclusion in the model. The total dataset was randomly divided into the training sample, testing sample and holdout sample in ratio of 3:1:1. After the training sample and testing sample developing the ANN model, the holdout sample was utilized to assess the accuracy of the model. ANN model analysis shows that the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC) of the overall ANN model were 92.3%, 93.5%, 87.0%, 94.2% and 0.955, respectively. We observed that the proposed model performed superbly on the prediction of DFU with a 91.6% accuracy. Evaluated with the holdout sample, the model accuracy, sensitivity, specificity, PPV and NPV were 88.9%, 90.0%, 88.5%, 75.0% and 95.8%, respectively. By contrast, the logistic regression model was inferior to the ANN model. The ANN model can accurately and reliably predict the occurrence and prognosis of a DFU according to clinical and lower extremity CTA data. We provided clinicians with a novel technical tool to develop clinical strategies before end-stage outcomes.

Global, Regional, and National Levels and Trends in the Burden of Pressure Ulcer from 1990 to 2019: A Systematic Analysis for the Global Burden of Disease 2019.

Pressure ulcer (PU) is a type of chronic ulcer, placing a high burden not only on patients' families but also on national healthcare systems globally. To determine the level, trends, and burden of PU worldwide and to provide an essential foundation for building targeted public policies on PUs at the national, regional, and global levels, data on PU were obtained from the Global Burden of Disease (GBD) 2019 Study. The incidence, disability-adjusted life years (DALYs), and deaths of PUs in 204 countries and regions from 1990 to 2019 were calculated and stratified by sex, age, geographical location, and sociodemographic index (SDI). The estimated annual percentage change (EAPC) of incidence, DALYs, and deaths was calculated to evaluate the temporal trends. A total of 3,170,796 new cases (95% uncertainty interval (UI), 3,499,729-2,875,433 cases) of PU were identified globally in 2019, more than 55% of which were among male individuals, and most of the new cases were concentrated in those 75-90 years of age. The burden of PU measured in DALYs was 481 423 (95% UI, 583 429-374 334) in 2019, 73% and 27% of which could be attributed to years of life lost (YLLs) and years lived with disability (YLDs), respectively. The burden increased gradually from 1990 to 2019 (from 267 846 [360 562-211 024] to 481 423 [95% UI, 583 429-374 334]). A total of 24 389 deaths were attributed to PU (95% UI, 31 260.82-17 299). The EAPC of incidence, DALYs, and deaths were negative in most regions, the age-standardized rate (ASR) of incidence, DALYs, and deaths were considered to be decreasing in most of the regions, and the EAPCs were negatively correlated with the SDI levels, universal health coverage (UHC), and gross domestic product (GDP), which shows that the ASRs of PU decreased as the economy developed and countries' healthcare system performances improved.

Dermal fibroblast from superficial layers of pig skin exhibits more proliferative capacity than that from deep layers.

OBJECTIVE: To further examine the feasibility of using pigs as an animal model for the study of dermal fibroblast heterogeneity and to explore the proliferative capacity of dermal fibroblasts from different layers of pig skin in vitro and in vivo. MATERIAL AND METHODS: Cultured superficial and deep dermal fibroblasts were subjected to cell growth assay, cell cycle analysis, immunocytochemical staining and western blotting for proliferating cell nuclear antigens. Moreover, skin samples autografted with superficial/deep dermal fibroblasts were subjected to immunohistochemical staining and western blotting for proliferating cell nuclear antigen. RESULTS: The cell growth assay showed that the growth curve of the superficial dermal fibroblast was progressively higher than that of the deep layer. The cell cycle analysis showed that the (G2+S) percentage of the superficial dermal fibroblasts was significantly higher than that of the deep layer fibroblasts. The immunocytochemical staining and western blotting showed that the expression of proliferating cell nuclear antigen in the cultured superficial dermal fibroblast was significantly higher than that of the deep layer cells. The immunohistochemical staining showed that the positive rate of proliferating cell nuclear antigen in the skin samples autografted with the superficial dermal fibroblast was significantly higher than that of the deep layer. CONCLUSIONS: This study has demonstrated that similar to human dermal fibroblasts, dermal fibroblasts from different layers of pig skin exhibit distinct proliferative capacity, which increases the feasibility of using pigs as an animal model for future studies on the heterogeneity of dermal fibroblasts.

Efficacy and safety of CO2 laser in the treatment of chronic wounds: A Retrospective Matched Cohort Trial.

OBJECTIVES: Treating chronic cutaneous wounds is challenging, and debridement is a central concept in treating them. Studies have shown that CO2 laser debridement can control local infection and promote the wound healing process. The present study aimed to investigate the efficacy and safety of fully ablative CO2 laser debridement compared to routine surgical debridement in the treatment of chronic wounds. METHODS: The retrospective cohort study was conducted on patients with chronic (>1 month) cutaneous wounds (≥1 cm2 ) between December 1, 2017, and December 1, 2020, in the Wound Healing Center at Shanghai Ruijin Hospital, China. Patients treated with CO2 laser debridement with a DEKA SmartXide2 C80 (DEKA) (the CO2 laser group) were compared with matched control patients with similar baseline characteristics who had undergone routine surgical debridement (the routine group). The primary outcome was time-to-heal (days) for chronic wounds in two groups, and secondary outcomes included the wound area and BWAT (Bates-Jensen wound assessment tool) score before treatment, and at 1, 2, 3, and 4 weeks after treatment. RESULTS: The study included 164 patients (82 in the CO2 laser group and 82 matched in the routine group). The time-to-heal for patients in the CO2 laser group (41.30 ± 17.11) was significantly shorter than that of the patients in the routine group (48.51 ± 24.32) (p = 0.015). At 3 and 4 weeks after treatment, the absolute wound area of the CO2 laser group was significantly smaller than that of the routine group. Also, the CO2 laser group exhibited a significantly lower relative area at 2, 3, and 4 weeks after treatment. The CO2 laser group yielded significantly lower BWAT scores at 2, 3, and 4 weeks after treatment. Additionally, the relative BWAT score was significantly lower in the CO2 laser group than the relative scores in the routine group at 2, 3, and 4 weeks after treatment. No adverse events related to the treatments were observed in either group during the study period. CONCLUSIONS: The present study has shown that fully ablative CO2 laser debridement has several advantages over routine sharp surgical debridement. It is superior at ameliorating wound status and reducing wound area, and it also significantly reduces the time-to-heal for chronic wounds, without causing any adverse events.

CO2 Laser Debridement and Negative Pressure Wound Therapy With Endoscopic Support for Treatment of Sinus Wound at the Ischial Tuberosity: Case Report.

The sinus tract of the ischial tuberosity is often caused by pressure injury. It has the characteristics of difficult treatment and high cost, which increases the anxiety of patients and reduces the quality of life of patients. This case report is to describe an effective method to treat sinus wound at the ischial tuberosity. A 53-year-old male suffered pressure ulcer with sinus wound at the left ischial tuberosity due to inadequate walking and sedentary activity. On the basis of pressure relief and immobilization, the patient was treated with CO2 laser debridement and negative pressure wound therapy under endoscope support 3 times, the deep of the sinus wound was completely closed, and then the residual superficial wound was treated by skin grafting. Follow-up of 1 year after healing showed no recurrence of wound.

Application of Compound Polymyxin B Ointment in the Treatment of Chronic Refractory Wounds.

The purpose of this study was to investigate the clinical efficacy of compound polymyxin B ointment for treating chronic refractory wounds. A retrospective analysis was performed on 111 patients who underwent chronic refractory wound treatment. Patients were divided into 2 groups, with 45 patients included in the experimental group (compound polymyxin B group) and 66 patients included in the control group (silver sulfadiazine group). After thorough debridement in both groups, either compound polymyxin B ointment or silver sulfadiazine cream was evenly applied to the patient's wound and covered with sterile gauze. In both groups, dressing changes were dependent on the wound's condition and secretions. Using the Bates-Jensen Wound Assessment Tool (BWAT), patients in both groups were scored, after which wound healing, infection, and healing time were compared. There was no significant difference in BWAT scores between the 2 groups on the 7th or 14th day; however, on the 21st day, the BWAT score in the experimental group was significantly lower than that of the control group. The difference was statistically significant (P < .05). There was no significant difference in the BWAT-I scores between the 2 groups on the seventh day. The healing time in the experimental group was significantly shorter than that of the control group, and the difference was statistically significant (P < .05). For the treatment of chronic refractory wounds, thorough debridement followed by compound polymyxin B ointment topical application can reduce and control wound infection effectively and accelerate the process of wound repair.

Pyridoxamine ameliorates methylglyoxal-induced macrophage dysfunction to facilitate tissue repair in diabetic wounds.

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound formed during hyperglycaemia. MGO combines with proteins to form advanced glycation end products (AGEs), leading to cellular dysfunction and organ damage. In type 2 diabetes mellitus (T2DM), the higher the plasma MGO concentration, the higher the lower extremity amputation rate. Here, we aimed to identify the mechanisms of MGO-induced dysfunction. We observed that the accumulation of MGO-derived AGEs in human diabetic wounds increased, whereas the expression of glyoxalase 1 (GLO1), a key metabolic enzyme of MGO, decreased. We show for the first time that topical application of pyridoxamine (PM), a natural vitamin B6 analogue, reduced the accumulation of MGO-derived AGEs in the wound tissue of type-2 diabetic mice, promoted the influx of macrophages in the early stage of tissue repair, improved the dysfunctional inflammatory response, and accelerated wound healing. In vitro, MGO damaged the phagocytic functions of M1-like macrophages induced by lipopolysaccharide (LPS), but not those of M0-like macrophages induced by PMA or of M2-like macrophages induced by interleukins 4 (IL-4) and 13 (IL-13); the impaired phagocytosis of M1-like macrophages was rescued by PM administration. These findings suggest that the increase in MGO metabolism in vivo might contribute to macrophage dysfunction, thereby affecting wound healing. Our results indicate that PM may be a novel therapeutic approach for treating diabetic wounds. MGO forms protein adducts that cause macrophage dysfunction. These adducts cause cell and organ dysfunction that is common in diabetes. Pyridoxamine scavenges MGO to ameliorate this dysfunction, promoting wound healing. Pyridoxamine could be used therapeutically to treat non-healing diabetic wounds.

Fractal analysis of rat dermal tissue in the different injury states.

Scar formation and chronic ulcers can develop following a skin injury. They are the result of the over- or underproduction of collagen. It is very important to evaluate the quality and quantity of the collagen that is produced during wound healing, especially with respect to its structure, as these factors are very important to a complicated outcome. However, there is no standard way to quantitatively analyse dermal collagen. As prior work characterised some potentially fractal properties of collagen, it was hypothesised that collagen structure could be evaluated with fractal dimension analysis. Small-angle X-ray scattering technology (SAXS) was used to evaluate the dermis of rats exposed to graft harvest, burn, and diabetic pathologic states. It was found that almost all collagen structures could be quantitatively measured with fractal dimension analysis. Further, there were significant differences in the three-dimensional (3-D) structure of normal collagen versus that measured in pathologic tissues. There was a significant difference in the 3-D structure of collagen at different stages of healing. The findings of this work suggest that fractal analysis is a good tool for wound healing analysis, and that quantitative collagen analysis is very useful for assessing the structure of dermal collagen.

Successful Postoperative Nephrocutaneous Fistula Treatment With Omental Flap Grafting: A Case Report.

Nephrocutaneous fistula (NCF) is a rare and severe complication of renal disease and surgical procedures. Treatments for NCF are based on the renal function, and can include nephrectomy, heminephrectomy, nephroureterectomy, endourological maneuvers or antibiotic therapy alone. Here we report a case of a chronic NCF which occurred 5 years after partial nephrectomy. In this report, we describe a new surgical approach for the management of a patient with postoperative NCF. In the present case, in addition to removing the fistulous tract, we also performed an omental flap grafting to tightly cover the kidney. In addition to limiting and controlling the local inflammation, the omental flap prevents contact between the kidney and the flank muscle on its posterior rim. No recurrence or complications occurred throughout 10 months of follow-up. The NCF was successfully treated with completely removal of the sinus tract and omental flap grafting, without nephrectomy. This case adds new aspects to the treatment of NCF.

The application value of computed tomography and magnetic resonance imaging sinography/fistulography in evaluating chronic wounds: a prospective study.

BACKGROUND: Chronic wounds are a worldwide health problem, with traditional imaging techniques failing in their accurate evaluation. Therefore, an effective imaging evaluation method is needed for the diagnosis and treatment or chronic wounds. This study is to investigate the application value of computed tomography (CT) and magnetic resonance imaging (MRI) sinography/fistulography in assessing the morphology and deep features of chronic wounds. METHODS: We prospectively enrolled 43 chronic wounds patients who received both CT and MRI sinography/fistulography. The morphology and deep features of chronic wound on CT and MRI images were independently evaluated by 2 experienced radiologists. Kappa value and intraclass correlation coefficient (ICC) were calculated to evaluate the interobserver agreement and the consistency between CT and MRI sinography/fistulography in assessing the shape, number of branches, and involvement of body cavity and bones of chronic wounds. RESULTS: There were substantial to almost perfect interobserver agreements for both CT and MRI sinography/fistulography in evaluating the morphology and deep features of chronic wounds. The consistency between CT and MRI was almost perfect for the 2 readers in evaluating the shape (reader 1, kappa value =1.000; reader 2, kappa value =0.932) and the number of branches [reader 1, ICC =0.951 (95% confidence interval: 0.909-0.973, P<0.001); reader 2, ICC =0.874 (95% confidence interval: 0.768-0.932, P<0.001)], and substantial to almost perfect when evaluating the involvement of body cavity (reader 1, kappa value =0.728; reader 2, kappa value =0.775) and bones (reader 1, kappa value =0.659; reader 2, kappa value =0.860). CONCLUSIONS: There was good interobserver agreement and consistency between CT and MRI sinography/fistulography in evaluating the morphology and deep features of chronic wounds.

Can fractal dimension analysis be used in quantitating collagen structure?

It is well known that collagen tissue, especially the collagen structure, plays an important role in wound healing. However, most research on collagen has been qualitative and morphological, based on sections, and cannot be used for real-time monitoring and clinical prediction. There are no standardized methods of quantitative analysis based on the whole skin sample in three dimensions (3-D). In order to explore a 3-D quantitative analysis, we developed a method that was derived from that of material science and physics, combined with our previous technique, X-ray scattering (SAXS). We hypothesized that the dermis might be analysed by fractal dimensions. To test this hypothesis, we performed the analysis in different pathological conditions, such as scar tissue, different time points after wounding, skin in different degrees of burns and skin in diabetes. The results showed that fractal dimension analysis could detect differences in different locations of the scar tissue, at different time points after wounding, and at a different extent of the severity of skin in diabetes. The research demonstrated that fractal dimension analysis can describe the 3-D structure of the collagen tissue of the skin, which will be beneficial for studying wound healing and finding new clinical treatments.

Distribution and Antibiotic Resistance Patterns of Pathogenic Bacteria in Patients With Chronic Cutaneous Wounds in China.

Background: To determine the distribution and antimicrobial susceptibility pattern of pathogenic bacteria in patients with chronic cutaneous wounds on a national scale. Methods: A retrospective study was conducted using the data recorded between January 1, 2018 and January1, 2020 in 195 hospitals across China. After screening the data, 815 patients with chronic wounds were finally analyzed. The data collected included information about the patients' general condition and local cutaneous wound assessments, especially microbial culture and antibiotic susceptibility tests. The analyses were performed using SPSS Version 26. Results: The study included 815 patients (290 [35.6%] females; 63 [50-74] years). The most common causes of chronic cutaneous wounds were diabetes (183, 22.5%), infection (178, 21.8%), and pressure (140, 17.2%). Among these, 521(63.9%) samples tested yielded microbial growth, including 70 (13.4%) polymicrobial infection and 451 (86.6%) monomicrobial infection. The positive rate of microbial culture was highest in wound tissue of ulcers caused by infection (87.6%), followed by pressure (77.1%), diabetes (68.3%), and venous diseases (67.7%). Bates-Jensen wound assessment tool (BWAT) scores >25 and wounds that lasted for more than 3 months had a higher positive rate of microbial culture. BWAT scores >25 and wounds in the rump, perineum, and feet were more likely to exhibit polymicrobial infection. A total of 600 strains were isolated, of which 46.2% (277 strains) were Gram-positive bacteria, 51.3% (308 strains) were Gram-negative bacteria, and 2.5% (15 strains) were fungi. The most common bacterial isolates were Staphylococcus aureus (29.2%), Escherichia coli (11.5%), Pseudomonas aeruginosa (11.0%), Proteus mirabilis (8.0%), and Klebsiella pneumoniae (5.8%). The susceptibility tests showed that 116 cultured bacteria were Multidrug resistant (MDR) strains. The resistance rates of S. aureus were 92.0% (161/175) to penicillin, 58.3% (102/175) to erythromycin, and 50.9% (89/175) to clindamycin. Vancomycin was the most effective antibiotic (0% resistance rate) against all Gram-positive bacteria. Besides, the resistance rates of E. coli were 68.1% (47/69) to ampicillin, 68.1% (47/69) to ciprofloxacin, 60.9% (42/69) to levofloxacin. However, all the isolated Gram-negative bacteria showed low resistance rates to tigecycline (3.9%) and amikacin (3.6%). Conclusions: The distribution of bacteria isolated from chronic cutaneous wounds varies with the BWAT scores, causes, duration, and the location of wounds. Multidrug resistance is a serious health issue, and therefore antibiotics used in chronic wounds must be under strict regulation. Our findings may help clinicians in making informed decisions regarding antibiotic therapy.

Different therapeutic effects between diabetic and non-diabetic adipose stem cells in diabetic wound healing.

OBJECTIVE: This study aimed to investigate how adipose tissue-derived stem cells (ASCs) from diabetic and from non-diabetic rats affect wound healing in different microenvironments. METHOD: The two types of ASC-rich cells were distinguished by characteristic surface antigen detection. The ASC-rich cells were transplanted into the wounds of diabetic and non-diabetic rats. Wound healing rates were compared and the healing process in the wound margin sections was used to determine how ASC-rich cells affect wound healing in different microenvironments. RESULTS: ASC density was decreased in diabetic rats. The generation time of ASC-rich cells from diabetic rats (d-ASC-rich cells) was longer than that of ASC-rich cells from non-diabetic rats. The number of pre-apoptotic cells in the third generation (passage 3) of d-ASC-rich cells was higher than that among the ASC-rich cells from non-diabetic rats. CD31 and CD34 expression was higher in d-ASC-rich cells than in ASC-rich cells from non-diabetic rats, whereas CD44 and CD105 expression was lower than that in ASC-rich cells from non-diabetic rats. Transplantation of ASC-rich cells from non-diabetic rats promoted wound healing in both non-diabetic and diabetic rats. In contrast, d-ASC-rich cells and enriched nuclear cells only promoted wound healing in non-diabetic rats. ASC-rich cell transplantation promoted greater tissue regeneration than d-ASC-rich cell transplantation. CONCLUSION: ASC-rich cells promoted wound healing in diabetic and non-diabetic rats. ASC density was lower in the adipose tissue of diabetic rats compared with non-diabetic rats. d-ASC-rich cells did not promote wound healing in diabetic rats, suggesting that caution is warranted regarding the clinical use of diabetic adipose stem cell transplantation for the treatment of diabetic wounds.

Effects of advanced glycation end products on neutrophil migration and aggregation in diabetic wounds.

Increased accumulation of advanced glycation end products (AGEs) in diabetic skin is closely related to delayed wound healing. Studies have shown that the concentration of AGEs is elevated in the skin tissues and not subcutaneous tissues in refractory diabetic wounds, which suggests there may be a causal relationship between the two. In the present study, in vitro experiments revealed that AGEs activated neutrophils, and the migratory and adhesive functions of neutrophils decreased once AGE levels reached a certain threshold. Different levels of AGE expression differentially affected the function of neutrophils. Messenger RNA (mRNA) sequencing analysis combined with real-time polymerase chain reaction (PCR) showed that poliovirus receptor (PVR/CD155) and CTNND1, which play a role in migration- and adhesion-related signaling pathways, were decreased following AGE stimulation. Consequently, neutrophils cannot effectively stimulate the formation of the inflammatory belt needed to remove necrotic tissues and defend against foreign microorganisms within diabetic chronic wounds. In addition, this phenomenon may be related to the differential accumulation of AGEs in different layers of the skin.