Using an artificial neural network to predict healing times and risk factors for venous leg ulcers

Risk predictions of surgical wound complications based on a machine learning algorithm: A systematic review

Surgical wounds may arise due to harm inflicted upon soft tissue during surgical intervention, and many complications and injuries may accompany them. These complications can lead to prolonged hospitalization and poorer clinical outcomes. Also, Machine learning (ML) is a Section of artificial intelligence (AI) that has emerged in medical care and is increasingly used for diagnosis, complications, prognosis and recurrence prediction. This study aims to investigate surgical wound risk predictions and management using a ML algorithm by R programming language analysis. The systematic review, following PRISMA guidelines, spanned electronic databases using search terms like 'machine learning', 'surgical' and 'wound'. Inclusion criteria covered experimental studies from 1990 to the present on ML's application in surgical wound evaluation. Exclusion criteria included studies lacking full text, focusing on ML in all surgeries, neglecting wound assessment and duplications. Two authors rigorously assessed titles, abstracts and full texts, excluding reviews and guidelines. Ultimately, relevant articles were then analysed. The present study identified nine articles employing ML for surgical wound management. The analysis encompassed various surgical procedures, including Cardiothoracic, Caesarean total abdominal colectomy, Burn plastic surgery, facial plastic surgery, laparotomy, minimal invasive surgery, hernia repair and unspecified surgeries. ML was skillful in evaluating surgical site infections (SSI) in seven studies, while two extended its use to burn-grade diagnosis and wound classification. Support Vector Machine (SVM) and Convolutional Neural Network (CNN) were the most utilized algorithms. ANN achieved a 96% accuracy in facial plastic surgery wound management. CNN demonstrated commendable accuracies in various surgeries, and SVM exhibited high accuracy in multiple surgeries and burn plastic surgery. In sum, these findings underscore ML's potential for significant improvements in postoperative management and the development of enhanced care techniques, particularly in surgical wound management.

Prognostic models for clinical outcomes in patients with venous leg ulcers: A systematic review

OBJECTIVE

The purpose of this review was to identify prognostic models for clinical application in patients with venous leg ulcers (VLUs).

METHODS

Literature searches were conducted in Embase, Medline, Cochrane, and CINAHL databases from inception to December 22, 2021. Eligible studies reported prognostic models aimed at developing, validating, and adjusting multivariable prognostic models that include multiple prognostic factors combined, and that predicted clinical outcomes. Methodological quality was assessed using the CHARMS checklist and PROBAST short form questionnaire.

RESULTS

Thirteen studies were identified, of which three were validation studies of previously published models, four reported derivation and validation of models, and the remainder reported derivation models only. There was substantial heterogeneity in the model characteristics, including 11 studies focused on wound healing outcomes reporting 91 different predictors. Three studies shared similar predicted outcomes, follow-up timepoint and used a Cox proportional hazards model. However, these models reported different predictor selection methods and different predictors and it was therefore not feasible to summarize performance, such as discriminative ability.

CONCLUSIONS

There are no standout risk prediction models in the literature with promising clinical application for patients with VLUs. Future research should focus on developing and validating high-performing models in wider VLU populations.

Evaluation of factors affecting the healing process of venous ulcers: A 12-week longitudinal study

The process of healing venous ulcers is complex and influenced by many factors. By identifying the risk factors that influence a slower healing process, it is possible to predict impending delays and plan an individualised care plan. We analysed our database of patients with venous ulcers and identified clinical and demographic factors that delay the healing process. The research analysed the medical records of 754 patients with VLUs at Chronic Wound Treatment Unit of the University Hospital treated between 2001 and 2019. In study, the majority (64.3%) were women, the mean age was 65.7 years. The median duration of Chronic Venous Insufficiency was 24 years, 52% patients had had the disease >20 years, and 296 (39.3%) had experienced ulceration >12 months. Most of the patients (85.8%) had comorbidities, 84% were obese. At 12-week follow-up, 432 of the 754 ulcers had healed. Identified independent predictors of slower ulcer healing rates: wound area greater than 8.25 cm2 , location of the ulceration other than the medial ankle area, underlying disease >20 years, the presence of multiple comorbidities, depth of the ulcer, the presence of an unpleasant smell and alert pathogens. The presence of redness resulted in faster healing of VLUc. Many factors influence the healing process of venous ulceration. The results of the study can help in planning patient care and implementing appropriate early strategies to promote healing.

Computer Science meets Vascular Surgery: Keeping a pulse on artificial intelligence

Artificial intelligence (AI)-based technologies have garnered interest across a range of disciplines in the past several years, with an even more recent interest in various health care fields, including Vascular Surgery. AI offers a unique ability to analyze health data more quickly and efficiently than could be done by humans alone and can be used for clinical applications such as diagnosis, risk stratification, and follow-up, as well as patient-used applications to improve both patient and provider experiences, mitigate health care disparities, and individualize treatment. As with all novel technologies, AI is not without its risks and carries with it unique ethical considerations that will need to be addressed before its broad integration into health care systems. AI has the potential to revolutionize the way care is provided to patients, including those requiring vascular care.

How quickly does a wound heal? Bayesian calibration of a mathematical model of venous leg ulcer healing

Chronic wounds, such as venous leg ulcers, are difficult to treat and can reduce the quality of life for patients. Clinical trials have been conducted to identify the most effective venous leg ulcer treatments and the clinical factors that may indicate whether a wound will successfully heal. More recently, mathematical modelling has been used to gain insight into biological factors that may affect treatment success but are difficult to measure clinically, such as the rate of oxygen flow into wounded tissue. In this work, we calibrate an existing mathematical model using a Bayesian approach with clinical data for individual patients to explore which clinical factors may impact the rate of wound healing for individuals. Although the model describes group-level behaviour well, it is not able to capture individual-level responses in all cases. From the individual-level analysis, we propose distributions for coefficients of clinical factors in a linear regression model, but ultimately find that it is difficult to draw conclusions about which factors lead to faster wound healing based on the existing model and data. This work highlights the challenges of using Bayesian methods to calibrate partial differential equation models to individual patient clinical data. However, the methods used in this work may be modified and extended to calibrate spatiotemporal mathematical models to multiple data sets, such as clinical trials with several patients, to extract additional information from the model and answer outstanding biological questions.

Randomized, double-blind clinical trial comparing the healing of stasis ulcers in lower limbs with standard hydrocolloid gel dressings and with dressings with Syzygium cumini extract

Objective

To evaluate the healing of venous ulcers in the lower limbs (VLU) using dressings with hydrocolloid gel associated with Syzygium cumini extract (SHG) compared to standard hydrocolloid gel dressings (HG).

Method

This prospective, double-blind, randomized trial recruited 90 patients with VLU divided into: dressings with SHG ( n = 44) and dressings with HG ( n = 46). Primary endpoint was healing in the 14th visit. Secondary endpoints were healing rate, complete healing during follow-up, and improvement in the pain scale and in quality of life.

Results

There were no significant between-group differences in healing ( p = 0.15). The wound area made healing difficult ( p = 0.008). Age, body mass index, and wound time demonstrated a tendency to worsen the healing. Positive culture for Pseudomonas aeruginosa resulted in 88% reduction in the healing risk ( p < 0.0001).

Conclusion

There was no difference between the dressings evaluated. The presence of Pseudomonas aeruginosa significantly impaired wound healing.

Allogeneic ABCB5+ mesenchymal stem cells for treatment-refractory chronic venous ulcers: a phase I/IIa clinical trial

A significant number of chronic venous ulcers (CVUs) fail to heal despite of guideline-conform standard of care. Skin-derived ABCB5+ mesenchymal stem cells (MSCs) can dampen the sustained IL-1β-driven inflammation present in chronic wounds. Based on their wound healing-facilitating effects in a mouse CVU model and an autologous first-in-human study, ABCB5+ MSCs have emerged as a potential candidate for cell-based advanced therapy of non-healing CVUs. In the present interventional, multicenter, single-arm, phase I/IIa clinical trial, subjects whose CVU had emerged as standard therapy-resistant received one or two topical applications of 1×106 allogeneic ABCB5+ MSCs/cm2 wound area in addition to standard treatment. Out of 83 treatment-emergent adverse events, only three were judged related to the cell product; they were mild or moderate and recovered without sequelae. Wound size markedly decreased from baseline to week 12, resulting in a median wound size reduction of 76% (full analysis set, N=31), 78% (per-protocol set, N=27) and 87% (subset of responders; n=21). In conclusion, the study treatment was well tolerated and safe. The treatment elicited a profound wound size reduction within 12 weeks, identifying ABCB5+ MSCs as a potential candidate for adjunctive therapy of otherwise incurable CVUs. These results justify the conduct of a larger, randomized, controlled trial to confirm clinical efficacy.

Artificial Intelligence Evidence-Based Current Status and Potential for Lower Limb Vascular Management

Consultation prioritization is fundamental in optimal healthcare management and its performance can be helped by artificial intelligence (AI)-dedicated software and by digital medicine in general. The need for remote consultation has been demonstrated not only in the pandemic-induced lock-down but also in rurality conditions for which access to health centers is constantly limited. The term “AI” indicates the use of a computer to simulate human intellectual behavior with minimal human intervention. AI is based on a “machine learning” process or on an artificial neural network. AI provides accurate diagnostic algorithms and personalized treatments in many fields, including oncology, ophthalmology, traumatology, and dermatology. AI can help vascular specialists in diagnostics of peripheral artery disease, cerebrovascular disease, and deep vein thrombosis by analyzing contrast-enhanced magnetic resonance imaging or ultrasound data and in diagnostics of pulmonary embolism on multi-slice computed angiograms. Automatic methods based on AI may be applied to detect the presence and determine the clinical class of chronic venous disease. Nevertheless, data on using AI in this field are still scarce. In this narrative review, the authors discuss available data on AI implementation in arterial and venous disease diagnostics and care.

Application of Artificial Intelligence in Community-Based Primary Health Care: Systematic Scoping Review and Critical Appraisal

BACKGROUND

Research on the integration of artificial intelligence (AI) into community-based primary health care (CBPHC) has highlighted several advantages and disadvantages in practice regarding, for example, facilitating diagnosis and disease management, as well as doubts concerning the unintended harmful effects of this integration. However, there is a lack of evidence about a comprehensive knowledge synthesis that could shed light on AI systems tested or implemented in CBPHC.

OBJECTIVE

We intended to identify and evaluate published studies that have tested or implemented AI in CBPHC settings.

METHODS

We conducted a systematic scoping review informed by an earlier study and the Joanna Briggs Institute (JBI) scoping review framework and reported the findings according to PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analysis-Scoping Reviews) reporting guidelines. An information specialist performed a comprehensive search from the date of inception until February 2020, in seven bibliographic databases: Cochrane Library, MEDLINE, EMBASE, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), ScienceDirect, and IEEE Xplore. The selected studies considered all populations who provide and receive care in CBPHC settings, AI interventions that had been implemented, tested, or both, and assessed outcomes related to patients, health care providers, or CBPHC systems. Risk of bias was assessed using the Prediction Model Risk of Bias Assessment Tool (PROBAST). Two authors independently screened the titles and abstracts of the identified records, read the selected full texts, and extracted data from the included studies using a validated extraction form. Disagreements were resolved by consensus, and if this was not possible, the opinion of a third reviewer was sought. A third reviewer also validated all the extracted data.

RESULTS

We retrieved 22,113 documents. After the removal of duplicates, 16,870 documents were screened, and 90 peer-reviewed publications met our inclusion criteria. Machine learning (ML) (41/90, 45%), natural language processing (NLP) (24/90, 27%), and expert systems (17/90, 19%) were the most commonly studied AI interventions. These were primarily implemented for diagnosis, detection, or surveillance purposes. Neural networks (ie, convolutional neural networks and abductive networks) demonstrated the highest accuracy, considering the given database for the given clinical task. The risk of bias in diagnosis or prognosis studies was the lowest in the participant category (4/49, 4%) and the highest in the outcome category (22/49, 45%).

CONCLUSIONS

We observed variabilities in reporting the participants, types of AI methods, analyses, and outcomes, and highlighted the large gap in the effective development and implementation of AI in CBPHC. Further studies are needed to efficiently guide the development and implementation of AI interventions in CBPHC settings.

Histopathology and immunohistochemical analysis of 5-fluorouracil and triamcinolone treated keloids in double-blinded randomized controlled trial

Keloids are a major complication related to surgical wound healing and very challenging condition to treat. Many treatment options are available, but the efficacy of the treatment is poor in most of cases and some keloids do not respond to the treatment at all. We compared the efficacy of intralesional 5-fluorouracil (5-FU) and triamcinolone (TAC) injections in a double-blind randomized controlled trial (RCT). Forty-three patients with 50 keloid scars were treated with either intralesional TAC or 5-FU-injections over 6 months. We wanted to find out whether biological features (cell density, cell proliferation rate, vascular density, myofibroblast numbers, steroid hormone receptor expression) in keloids could be used to predict the response to therapy and define the biological changes that take place in patients receiving a response. As there was no statistically significant difference in the remission rate between TAC and 5-FU treatments, all patients were combined and analyzed as responders and nonresponders. Although responders have slightly more myofibroblasts than the nonresponders in their keloids in the pretreatment biopsy samples, we could not identify a single predictive factor that could identify those patients that respond to drug injections. The good clinical response to therapy is associated with the simultaneous reduction of myofibroblasts in the keloid. This study demonstrates that myofibroblasts are reduced in number in those keloids that were responsive to therapy, and that both 5-FU and TAC injections are useful for keloid treatment.

The Wound Healing Index for Predicting Venous Leg Ulcer Outcome

Objective: To develop a venous leg ulcer (VLU) risk stratification system for use in research and clinical practice. Approach: U.S. Wound Registry data were examined retrospectively and assigned an outcome. Bivariate analysis identified significant variables (p < 0.05) that were used to create a multivariable logistic regression model. Ulcers with data for wound area at the first visit before debridement were included in regression analysis, which was based on a 90% development sample. The model was validated on a hold-out 10% data sample. Results: The original dataset included 26,713 VLUs, of which 11,773 ulcers were eligible for preliminary analysis and 10,942 ulcers were eligible for regression analysis. The 90% development model included 9,898 ulcers, of which 7,498 healed (75.8%). The 10% validation sample included 1,044 ulcers, of which 809 healed (77.5%). The following variables significantly predicted healing: number of concurrent wounds of any etiology, wound size, wound age (in days), evidence of bioburden/infection, being nonambulatory, and hospitalization for any reason. Innovation: The VLU Wound Healing Index (WHI) is a comprehensive, validated risk stratification model for predicting VLU healing that incorporates patient- and wound-specific variables. Conclusions: The WHI can identify which VLUs most likely require adjunctive therapies to heal, prioritize referral to venous experts, risk-stratify ulcers to create more generalizable clinical trials and understand the impact of clinical interventions. The Centers for Medicare and Medicaid Services accepts this method for reporting VLU outcome under the Quality Payment Program.

Wound Closure Outcomes Suggest Clinical Equivalency Between Lyopreserved and Cryopreserved Placental Membranes Containing Viable Cells

Objective: To evaluate the clinical outcomes of lyopreserved placental membrane containing viable cells (vLPM) in the treatment of nonhealing wounds of various etiologies, and to compare them to those previously reported for cryopreserved placental membrane containing viable cells (vCPM).

Approach: Patients with nonhealing wounds who qualified to receive advanced wound therapies were consecutively enrolled and treated weekly with vLPM plus standard of care (SOC) at five centers. Data were de-identified and retrospectively analyzed. Outcomes included closure, time to closure, number of vLPM applications, and adverse events (AEs).

Results: Seventy-eight patients with 98 wounds (41 diabetic foot ulcers [DFUs], 19 venous leg ulcers [VLUs], 10 surgical, and 28 others) with an average size of 13.3 cm² and 8.7 months duration were treated. Fifty-eight of the 98 wounds (59.2%) achieved complete closure with median time to closure of 63 days and 6 vLPM applications. The closure by wound etiology was 63% for DFUs, 47% for VLUs, 70% for surgical wounds, and 57% for other types of wounds. Similar closure rates have been previously demonstrated for vCPM. Wound duration was the main predictor of closure: 65.8% versus 30.0% (p = 0.004) closure was achieved for wounds of ≤12 and >12 months duration, respectively. There were no AEs related to vLPM application.

Innovation: This is the first multicenter case series evaluating the clinical outcomes of vLPM in a real-world setting.

Conclusion: These results support clinical equivalency between the two placental membrane formulations with the added convenience of room-temperature storage for vLPM, allowing it to be used in any wound-care setting.

Potential prognostic factors for delayed healing of common, non-traumatic skin ulcers: A scoping review

Healing of non-traumatic skin ulcers is often suboptimal. Prognostic tools that identify people at high risk of delayed healing within the context of routine ulcer assessments may improve this, but robust evidence on which factors to include is lacking. Therefore, we scoped the literature to identify which potentially prognostic factors may warrant future systematic reviews and meta-analyses. We conducted electronic searches in MEDLINE and Embase to identify studies in English published between 1997 and 2017 that tested the association between healing of the three most common non-traumatic skin ulcers encountered by health care professionals (venous leg, diabetic foot, and pressure ulcers) and patient characteristics, ulcer characteristics, and results from clinical investigations. We included 42 studies that investigated factors which may be associated with the healing of venous leg ulcers (n = 17), diabetic foot ulcers (n = 15), and pressure ulcers (n = 10). Across ulcer types, ulcer characteristics were most commonly reported as potential prognostic factors for healing (n = 37), including the size of the ulcer area (n = 29) and ulcer duration at first assessment (n = 16). A total of 35 studies investigated the prognostic value of patient characteristics (n = 35), including age (n = 31), gender (n = 30), diabetes (n = 22), smoking status (n = 15), and history of deep vein thrombosis (DVT) (n = 13). Of these studies, 23 reported results from clinical investigations as potential prognostic factors, with the majority regarding vessel quality. Age, gender, diabetes, smoking status, history of DVT, ulcer area, and ulcer duration at time of first assessment warrant a systematic review and meta-analysis to quantify their prognostic value for delayed ulcer healing.

Scarless wound healing: From development to senescence

An essential element of tissue homeostasis is the response to injuries, cutaneous wound healing being the most studied example. In the adults, wound healing aims at quickly restoring the barrier function of the skin, leading however to scar, a dysfunctional fibrotic tissue. On the other hand, in fetuses a scarless tissue regeneration takes place. During ageing, the wound healing capacity declines; however, in the absence of comorbidities a higher quality in tissue repair is observed. Senescent cells have been found to accumulate in chronic unhealed wounds, but more recent reports indicate that their transient presence may be beneficial for tissue repair. In this review data on skin wound healing and scarring are presented, covering the whole spectrum from early embryonic development to adulthood, and furthermore until ageing of the organism.

Functional characterization of collaterals in the human gingiva by laser speckle contrast imaging

OBJECTIVE

The rate of blood flow between the various areas of the gingiva in resting position and under challenge is unknown. In this study, the LSCI method was used to map spatial and temporal changes in gingival blood flow after transient compression.

METHODS

Horizontal, vertical, and papilla base compressions were applied on the attached gingiva in 21 healthy patients (13 women, 8 men). LSCI was used to determine dynamic changes in regional blood flow during a five-second occlusion interval and subsequent reperfusion for twenty minutes.

RESULTS

Resting blood flow in the attached gingiva apical to the papillae was higher as compared to that in the midbuccal area of the teeth. During short-term horizontal compression, ischemia was greater coronal than apical to the occlusion line. Postocclusive hyperemia was observed not only in the regions affected by ischemia but encompassed a wider area. Hyperemic response was more pronounced and prolonged in male than in female patients.

CONCLUSIONS

Blood flow in the attached gingiva shows spatial differences. Our findings corroborate the apicocoronal orientation of blood circulation. Periodontal and papillary collaterals may have little role in the blood supply of the adjacent attached gingiva under physiological conditions.

The effect of estrogen on diabetic wound healing is mediated through increasing the function of various bone marrow-derived progenitor cells

OBJECTIVE

Endothelial progenitor cells (EPCs) are the key cells of postnatal neovascularization, and mesenchymal stem cells (MSCs) possess pluripotent differentiation capacity and contribute to tissue regeneration and wound healing. Both EPCs and MSCs are critical to the wound repair process, which is hindered in diabetes mellitus. Diabetes has been shown to decrease the function of these progenitor cells, whereas estrogen has beneficial wound healing effects. However, the role of estrogen in modulating EPC and MSC biology in diabetes is unknown. We investigated the effect of estrogen on improving bone marrow (BM)-derived EPC and MSC function using a murine diabetic wound healing model.

METHODS

Female diabetic db⁺/db⁺ and nondiabetic control mice were wounded cutaneously and treated with topical estrogen or placebo cream. On day 5 after wounding, BM cells were harvested to quantify EPC number and colony-forming units of EPCs and MSCs. Wound healing rate was concurrently studied. Vessel density and scar density were then quantified using whole body perfusion and laser confocal microscopy. EPC recruitment was documented by immunohistochemistry to identify CD34- and vascular endothelial growth factor receptor 2-positive cells in the vessel wall. Data were analyzed by analysis of variance.

RESULTS

Topical estrogen significantly increased colony-forming units of both EPCs and MSCs compared with placebo treatment, indicating improved viability and proliferative ability of these cells. Consistently, increased recruitment of EPCs to diabetic wounds and higher vessel density were observed in estrogen-treated compared with placebo-treated mice. Consequently, topical estrogen significantly accelerated wound healing as early as day 6 after wounding. In addition, scar density resulting from collagen deposition was increased in the estrogen-treated group, reflecting increased MSC activity and differentiation.

CONCLUSIONS

Estrogen treatment increases wound healing and wound neovascularization in diabetic mice. Our data implicate that these beneficial effects may be mediated through improving the function of BM-derived EPCs and MSCs.

Predicting delayed healing: The diagnostic accuracy of a venous leg ulcer risk assessment tool

The aim of this study was to validate a newly developed tool that can predict the risk of failure to heal of a venous leg ulcer in 24 weeks. The risk assessment tool was validated, and performance of the tool was assessed using Area Under the Receiver Operating Characteristic Curve (AUC) analysis. Retrospective and prospective validation was conducted through multi-site, longitudinal studies. In the retrospective study (n = 318), 30% of ulcers did not heal within 24 weeks, with the tool demonstrating an AUC of 0.80 (95% CI, 0.68-0.93, P < .001) for the total score. In the prospective study across 10 clinical sites (n = 225), 31% (n = 68) of ulcers did not heal within 24 weeks. Participants were classified with the RAT at enrolment as being at low risk (27%), moderate risk (53%) or high risk (20%) of delayed healing; the proportion of wounds unhealed at 24 weeks was 6%, 29% and 59%, respectively. Validation results of the total score indicated good discrimination and goodness of fit with an AUC of 0.78 (95% CI, 0.71-0.85, P < .001). Validation of this risk assessment tool offers assurance that realistic outcomes can be predicted for patients, and scores can guide early decisions on interventions to address specific risk factors for failing to heal, thus promoting timely healing.

Testosterone Prevents Cutaneous Ischemia and Necrosis in Males Through Complementary Estrogenic and Androgenic Actions

OBJECTIVE

Chronic nonhealing wounds are a substantial medical concern and are associated with morbidity and mortality; thus, new treatment strategies are required. The first step toward personalized/precision medicine in this field is probably in taking sex differences into account. Impaired wound healing is augmented by ischemia, and we previously demonstrated that 17β-estradiol exerts a major preventive effect against ischemia-induced skin flap necrosis in female mice. However, the equivalent effects of testosterone in male mice have not yet been reported. We then investigated the role of steroid hormones in male mice using a skin flap ischemia model.

APPROACH AND RESULTS

Castrated male mice developed skin necrosis after ischemia, whereas intact or castrated males treated with testosterone were equally protected. Testosterone can (1) activate the estrogen receptor after its aromatization into 17β-estradiol or (2) be reduced into dihydrotestosterone, a nonaromatizable androgen that activates the androgen receptor. We found that dihydrotestosterone protected castrated wild-type mice by promoting skin revascularization, probably through a direct action on resistance arteries, as evidenced using a complementary model of flow-mediated outward remodeling. 17β-estradiol treatment of castrated male mice also strongly protected them from ischemic necrosis through the activation of estrogen receptor-α by increasing skin revascularization and skin survival. Remarkably, 17β-estradiol improved skin survival with a greater efficiency than dihydrotestosterone.

CONCLUSIONS

Testosterone provides males with a strong protection against cutaneous necrosis and acts through both its estrogenic and androgenic derivatives, which have complementary effects on skin survival and revascularization.

Ulcer area reduction at 2 weeks predicts failure to heal by 24 weeks in the venous leg ulcers of patients living alone

OBJECTIVE

Chronic wounds are costly and affect approximately 1-2% of the population. Venous disease is responsible for about 60% of all chronic leg ulcers and these ulcers can be debilitating, with evidence of a decreased quality of life. Unfortunately, up to 30% of venous leg ulcers (VLUs) fail to heal, despite best practice treatment. This study aimed to identify risk factors associated with delayed healing in participants with VLUs and in particular, whether psychosocial factors play a part in this process.

METHOD

A secondary analysis was conducted of a large data set of clinical, wound healing, health, social, economic and psychological data collected in previous prospective studies of participants with VLUs. Generalised linear mixed modelling was used to identify independent predictors of failure to heal after 24 weeks.

RESULTS

We recruited 247 participants with 318 VLUs from hospital and community settings. Findings revealed that four early predictors were independently significantly associated with failure to heal by 24 weeks. These were: participants who lived alone (OR 2.3, 95%CI [1.13-4.61], p=0.03); had less than 25% reduction in ulcer area within two weeks of treatment (OR 10.07, 95%CI [4.60-22.19], p<0.001); had higher ulcer severity scores (OR 5.1, 95%CI [2.33-11.88], p=0.001); and participants who were not treated with high level compression therapy (i.e.>30 mmHg) at the time of assessment (OR 4.18, 95% CI [1.95-8.97], p=0.002).

CONCLUSION

Identified risk factors offer an opportunity for clinicians to determine realistic outcomes for their patients and to guide decisions on early referral and implementation of tailored adjunctive interventions. Additionally, findings from this study suggest health professionals need to assess and address not only clinical risk factors but also social risk factors, when planning interventions to promote healing.

Transition from inflammation to proliferation: a critical step during wound healing

The ability to rapidly restore the integrity of a broken skin barrier is critical and is the ultimate goal of therapies for hard-to-heal-ulcers. Unfortunately effective treatments to enhance healing and reduce scarring are still lacking. A deeper understanding of the physiology of normal repair and of the pathology of delayed healing is a prerequisite for the development of more effective therapeutic interventions. Transition from the inflammatory to the proliferative phase is a key step during healing and accumulating evidence associates a compromised transition with wound healing disorders. Thus, targeting factors that impact this phase transition may offer a rationale for therapeutic development. This review summarizes mechanisms regulating the inflammation-proliferation transition at cellular and molecular levels. We propose that identification of such mechanisms will reveal promising targets for development of more effective therapies.

Meta-analytic approaches to determine gender differences for delayed healing in venous leg ulcers

Objective The aim of this analysis was to perform a meta-analysis evaluating gender difference of delayed healing risk in patients with venous leg ulcers. Methods We searched the PubMed and Web of Knowledge from their inception to 4 July 2015. The meta-analysis of pooled odds ratio and 95% confidence interval for venous leg ulcers healing risk were calculated. Results Twelve studies with 4453 patients were included in the meta-analysis. The pooled odds ratio for healing rate stratified by gender was 1.055 (95% CI 0.955-1.165; Z = 1.05, p = 0.292) by fix-effects model. The Begg's test (z = 2.67, p = 0.007), the Egger's test (t = 4.00, p = 0.003), and asymmetric funnel plot suggested there was significant publication bias. Subgroup analysis showed the pooled odds ratios were 1.048 (95% CI 0.945-1.162; Z = 0.88, p = 0.376) in prospective studies and 1.439 (95% CI 0.757-2.736; Z = 1.11, p = 0.266) in retrospective studies. Sensitivity analyses by only pooled adjusted odds ratios showed the pooled odds ratio was 1.049 (95% CI 0.946-1.163; Z = 0.91, p = 0.365), which indicated the results of meta-analysis were robust. Meta-regression analysis showed the healing rate odds ratio stratified by gender was not related with healing rate (t = 0.73, p = 0.484). Conclusion Our meta-analysis indicates that no gender difference existed for delayed healing in venous leg ulcers. Our results may be also useful in developing a risk score for failure of venous leg ulcers to heal.

Risk factors for delayed healing in venous leg ulcers: a review of the literature

BACKGROUND

Chronic leg ulcers, remaining unhealed after 4-6 weeks, affect 1-3% of the population, with treatment costly and health service resource intensive. Venous disease contributes to approximately 70% of all chronic leg ulcers and these ulcers are often associated with pain, reduced mobility and a decreased quality of life. Despite evidence-based care, 30% of these ulcers are unlikely to heal within a 24-week period and therefore the recognition and identification of risk factors for delayed healing of venous leg ulcers would be beneficial.

AIM

To review the available evidence on risk factors for delayed healing of venous leg ulcers.

METHODS

A review of the literature in regard to risk factors for delayed healing in venous leg ulcers was conducted from January 2000 to December 2013. Evidence was sourced through searches of relevant databases and websites for resources addressing risk factors for delayed healing in venous leg ulcers specifically.

RESULTS

Twenty-seven studies, of mostly low-level evidence (Level III and IV), identified risk factors associated with delayed healing. Risk factors that were consistently identified included: larger ulcer area, longer ulcer duration, a previous history of ulceration, venous abnormalities and lack of high compression. Additional potential predictors with inconsistent or varying evidence to support their influence on delayed healing of venous leg ulcers included: decreased mobility and/or ankle range of movement, poor nutrition and increased age.

DISCUSSION

Findings from this review indicate that a number of physiological risk factors are associated with delayed healing in venous leg ulcers and that social and/or psychological risk factors should also be considered and examined further.

CONCLUSION

The findings from this review can assist health professionals to identify prognostic indicators or risk factors significantly associated with delayed healing in venous leg ulcers. This will facilitate realistic outcome planning and inform implementation of appropriate early strategies to promote healing.

Delayed cutaneous wound healing in aged rats compared to younger ones

Delayed wound healing in elderly males is a complex process in which the factors responsible are not fully understood. This study investigated the hormonal, oxidative and angiogenic factors affecting wound healing in aged rats. Two groups consisting of eight healthy male Wistar Albino rats [young (30 ± 7 days) and aged (360 ± 30 days)], and a cutaneous incision wound healing model were used. Scar tissue samples from wounds on the 7th, 14th and 21st days of healing were evaluated for hydroxyproline and vascular endothelial growth factor content. Macrophage, lymphocyte, fibroblast and polymorphonuclear cell infiltration; collagen formation and vascularization were assessed by light and electron microscopy. The free oxygen radical content of the wounds was measured by a chemiluminescence method. Blood sample analysis showed that the hydroxyproline and total testosterone levels were significantly higher, and the oxygen radical content was significantly lower in young rats. Histopathological, immunohistochemical and ultrastructural evaluations revealed higher amounts of fibroblasts and collagen fibers, and more vascularization in young rats. These results are indicative of the delayed wound healing in aged rats. A combination of multiple factors including hormonal regulation, free oxygen radicals and impaired angiogenesis appears to be the cause of delayed cutaneous healing.

Relationships between preventive activities, psychosocial factors and recurrence of venous leg ulcers: a prospective study

AIM

The aim of this study was to identify relationships between preventive activities, psychosocial factors and leg ulcer recurrence in patients with chronic venous leg ulcers.

BACKGROUND

Chronic venous leg ulcers are slow to heal and frequently recur, resulting in years of suffering and intensive use of healthcare resources.

METHODS

A prospective longitudinal study was undertaken with a sample of 80 patients with a venous leg ulcer recruited when their ulcer healed. Data were collected from 2006 to 2009 from medical records on demographics, medical history and ulcer history; and from self-report questionnaires on physical activity, nutrition, preventive activities and psychosocial measures. Follow-up data were collected via questionnaires every 3 months for 12 months after healing. Median time to recurrence was calculated using the Kaplan-Meier method. A Cox proportional-hazards regression model was used to adjust for potential confounders and determine effects of preventive strategies and psychosocial factors on recurrence.

RESULTS

There were 35 recurrences in a sample of 80 participants. Median time to recurrence was 27 weeks. After adjustment for potential confounders, a Cox proportional hazards regression model found that at least an hour/day of leg elevation, 6 or more days/week in Class 2 (20-25 mmHg) or 3 (30-40 mmHg) compression hosiery, higher social support scale scores and higher General Self-Efficacy scores remained significantly associated (P < 0·05) with a lower risk of recurrence, while male gender and a history of deep vein thrombosis remained statistically significant risk factors for recurrence.

CONCLUSION

Results indicate that leg elevation, compression hosiery, high levels of self-efficacy and strong social support will help prevent recurrence.

Neural network adapted to wound cell analysis in surgical patients

Assessment of the real state of wound healing of closed surgical wounds is uncertain both clinically and from conventional laboratory tests. Therefore, a novel approach based on early analysis of exactly timed wound cells, computerized further with an artificial neural network, was developed. At the end of routine surgery performed on 481 children under 18 years of age, a specific wound drain Cellstick™ was inserted subcutaneously between the wound edges to harvest wound cells. The Cellsticks™ were removed from 1 to 50 hours, mainly at hour 3 or 24 postsurgery. Immediately, the cellular contents were washed out using a pump constructed for the purpose. After cytocentrifugation, the cells were stained and counted differentially. Based on their relative proportions at selected time intervals, an artificial self-organizing neural map was developed. This was further transformed to a unidirectional linear graph where each node represents one set of relative cell quantities. As early as 3 hours, but more precisely 24 hours after surgery, the location of the nodes on this graph showed individually the patients' initial speed of wound inflammatory cell response. Similarly, timed Cellstick™ specimens from new surgical patients could be analyzed, computerized, and compared with these node values to assess their initial speed in wound inflammatory cell response. Location of the node on the graph does not express the time lapse after surgery but the speed of wound inflammatory cell response in relation to that of other patients.

Monocyte/macrophage androgen receptor suppresses cutaneous wound healing in mice by enhancing local TNF-alpha expression

Cutaneous wounds heal more slowly in elderly males than in elderly females, suggesting a role for sex hormones in the healing process. Indeed, androgen/androgen receptor (AR) signaling has been shown to inhibit cutaneous wound healing. AR is expressed in several cell types in healing skin, including keratinocytes, dermal fibroblasts, and infiltrating macrophages, but the exact role of androgen/AR signaling in these different cell types remains unclear. To address this question, we generated and studied cutaneous wound healing in cell-specific AR knockout (ARKO) mice. General and myeloid-specific ARKO mice exhibited accelerated wound healing compared with WT mice, whereas keratinocyte- and fibroblast-specific ARKO mice did not. Importantly, the rate of wound healing in the general ARKO mice was dependent on AR and not serum androgen levels. Interestingly, although dispensable for wound closure, keratinocyte AR promoted re-epithelialization, while fibroblast AR suppressed it. Further analysis indicated that AR suppressed wound healing by enhancing the inflammatory response through a localized increase in TNF-alpha expression. Furthermore, AR enhanced local TNF-alpha expression via multiple mechanisms, including increasing the inflammatory monocyte population, enhancing monocyte chemotaxis by upregulating CCR2 expression, and enhancing TNF-alpha expression in macrophages. Finally, targeting AR by topical application of a compound (ASC-J9) that degrades AR protein resulted in accelerated healing, suggesting a potential new therapeutic approach that may lead to better treatment of wound healing.

Delayed wound healing in elderly people

Our ability to heal wounds deteriorates with age, leading in many cases to a complete lack of repair and development of a chronic wound. Moreover, as the elderly population continues to grow the prevalence of non-healing chronic wounds is escalating. Cutaneous wound repair occurs through a combination of overlapping phases, including an initial inflammatory response, a proliferative phase and a final remodelling phase. In elderly subjects the inflammatory response is delayed, macrophage and fibroblast function compromised, angiogenesis reduced and re-epithelialization inhibited. Whilst a large body of historic research describes the defective processes that lead to delayed healing, only recently have the molecular mechanisms by which these defects arise begun to be elucidated. Current therapies available for treatment of chronic wounds in elderly people are surprisingly limited and generally ineffective. Thus there is an urgent need to develop new therapeutic strategies based on these recent molecular and cellular insights.

Unique and synergistic roles for 17beta-estradiol and macrophage migration inhibitory factor during cutaneous wound closure are cell type specific

The cutaneous wound healing response is complex, comprising numerous overlapping events including inflammation, fibroblast migration, reepithelialization, and wound contraction. With increased age and resultant reduced systemic estrogens, these processes are disrupted and delayed healing ensues. We have demonstrated previously that the proinflammatory cytokine macrophage migration inhibitory factor (MIF) acts as a global regulator of wound healing mediating the majority of estrogen's healing promoting activity. MIF is expressed by numerous wound cell types yet the interaction between estrogens and MIF at the cellular level is still poorly understood. In this study we demonstrate novel accelerated healing in MIF null mice using an excisional wound model. Moreover, we show cell-type-specific differences in the effects of 17beta-estradiol and/or MIF on the cellular function of a range of wound cell types in vitro. Intriguingly, 17beta-estradiol is able to promote the migration of all cell types studied indicating a clear role for cell migration in accelerated wound healing.

Androgens and ageing of the skin

PURPOSE OF REVIEW

This study reviews current advances in our understanding of the role of androgens in the initiation of skin ageing.

RECENT FINDINGS

Skin and its appendages being a steroidogenic tissue itself can be affected to a large extent by sex steroids. Amongst them, androgens display a distinguished role. They modulate epidermal and dermal thickness as proven in a variety of studies measuring gender-specific differences. With advanced age, changes in the circulating androgen levels may alter not only the morphology but also key functions of the skin such as epidermal barrier homeostasis and wound healing, sebaceous gland growth and differentiation and hair growth.

SUMMARY

Consequently, skin becomes susceptible to infections and several disease states. Androgen treatment has been proposed to be an effective way to reverse the age-associated deterioration of skin; however, further research is needed to translate current findings to clinically significant diagnostic and therapeutic applications.

5alpha-dihydrotestosterone (DHT) retards wound closure by inhibiting re-epithelialization

The ongoing search for explanations as to why elderly males heal acute skin wounds more slowly than do their female counterparts (and are more strongly disposed to conditions of chronic ulceration) has identified endogenous oestrogens and androgens as being respectively enhancers and inhibitors of repair. We previously demonstrated that blocking the conversion of testosterone to 5alpha-dihydrotestosterone (DHT) limits its ability to impair healing, suggesting that DHT is a more potent inhibitor of repair than is testosterone. The present study aimed to delineate the central mechanisms by which androgens delay repair. Whilst the contractile properties of neither rat wounds in vivo nor fibroblast-impregnated collagenous discs in vitro appeared to be influenced by androgen manipulations, the global blockade of DHT biosynthesis markedly accelerated re-epithelialization of incisional and excisional wounds and reduced local expression of beta-catenin, a key inhibitor of repair. Moreover, DHT retarded the in vitro migration of epidermal keratinocytes following scratch wounding. By contrast, it failed to influence the migratory and proliferative properties of dermal fibroblasts, suggesting that its primary inhibitory effect is upon re-epithelialization. These novel findings may be of particular significance in the context of chronic ulceration, for which being male is a key risk factor.

Sex dimorphism in wound healing: the roles of sex steroids and macrophage migration inhibitory factor

That endogenous sex steroid hormones profoundly influence the response to cutaneous injury is well established. How they and other factors combine to direct repair in male and female animals is much less well understood. Using a murine incisional wound-healing model, we investigated the roles of circulating sex steroids, macrophage migration inhibitory factor (MIF) (the mediator of delayed healing in ovariectomized animals), and hormone- and MIF-independent factors in controlling repair. We report that d 3 wounds, of comparable size in intact male and female mice, are significantly larger in ovariectomized female animals than in castrated males, suggesting that native sex hormones mask inherent underlying differences in the ways in which males and females respond to wounding. Wound MIF levels were comparable in intact male and female mice but greater in ovariectomized females than castrated males. Furthermore, wound levels of Jun activation domain-binding protein 1 (JAB1), a key factor by which MIF activates intracellular responses, were increased through ovariectomy and greater in ovariectomized females than castrated males. This difference in wound JAB1 levels may underscore the marked sex difference we observed in the responses of MIF knockout mice to the local application of MIF: healing was impaired in ovariectomized females but not castrated males. Separately, systemic treatment with androgens and estrogens yielded contrasting effects on repair in male and female animals. Collectively, the presented data indicate sex divergence in wound healing to be multifaceted, being strongly influenced by MIF and seemingly limited by the combined actions of gonadal steroids.

Estrogen, not intrinsic aging, is the major regulator of delayed human wound healing in the elderly

Analysis of gene expression in male elderly and young human wounds suggests that estrogen has a more profound influence on aging than previously thought.

Background

Multiple processes have been implicated in age-related delayed healing, including altered gene expression, intrinsic cellular changes, and changes in extracellular milieu (including hormones). To date, little attempt has been made to assess the relative contribution of each of these processes to a human aging phenomenon. The objective of this study is to determine the contribution of estrogen versus aging in age-associated delayed human wound healing.

Results

Using an Affymetrix microarray-based approach we show that the differences in gene expression between male elderly and young human wounds are almost exclusively estrogen regulated. Expression of 78 probe sets was significantly decreased and 10 probe sets increased in wounds from elderly subjects (with a fold change greater than 7). A total of 83% of down-regulated probe sets and 80% of up-regulated probe sets were estrogen-regulated. Differentially regulated genes were validated at the level of gene and protein expression, with genes identified as estrogen-regulated in human confirmed as estrogen-dependent in young estrogen depleted mice in vivo. Moreover, direct estrogen regulation is demonstrated for three array-identified genes, Sele, Lypd3 and Arg1, in mouse cells in vitro.

Conclusion

These findings have clear implications for our understanding of age-associated cellular changes in the context of wound healing, the latter acting as a paradigm for other age-related repair and maintenance processes, and suggest estrogen has a more profound influence on aging than previously thought.

Transcriptional control of wound repair

Injury to the skin initiates a complex process of events involving inflammation as well as the formation and remodeling of new tissue. These processes result in at least partial reconstitution of the injured skin. However, wounds in adult mammals heal with a scar, which is accompanied by functional and aesthetic impairments. In addition to this problem, a large number of patients, in particular in the aged population, suffer from chronic, nonhealing ulcers. Therefore, there is a strong need to improve the wound healing process. This requires a thorough understanding of the underlying molecular and cellular mechanisms. During the past several years, important regulators of the wound healing process have been identified. In particular, the growth factors and matrix proteins, which orchestrate skin repair, have been characterized in detail. By contrast, much less is known about the transcription factors, which regulate gene expression at the wound site. This review summarizes recent data on the expression of transcription factors in skin wounds and their functions in the repair process.

Sex steroids and cutaneous wound healing: the contrasting influences of estrogens and androgens

The increased prevalence in the elderly of chronic wound-healing conditions, such as venous and diabetic ulceration, is firmly established. This same population additionally suffers from impaired healing of acute wounds, which are characterized by delayed closure, increased local inflammation, and excessive proteolytic activity. In females, this decline in the effectiveness of skin repair mechanisms follows the menopause, and a series of clinical studies has identified estrogens as being endogenous enhancers of healing processes. The administration of 17beta-estradiol, either systemically or topically, has been shown to reverse the fundamental repair defects observed in postmenopausal women. By contrast, androgenic species retard repair and interfere with the accumulation of the structural proteins that reconstitute the damaged dermis. Since estrogen-based hormone replacement therapy produces wide-ranging effects, not all of which are considered to be desirable, more recent studies have sought to identify downstream mediators of estrogenic effects in order to formulate better targeted strategies for improving skin repair in the elderly.

Androgens influence expression of matrix proteins and proteolytic factors during cutaneous wound healing

Excessive proteolytic activity is a feature of chronic wounds such as venous ulcers, in which resolution of the inflammatory response fails and restorative matrix accumulation is delayed as a consequence. The inflammatory actions of native androgens during the healing of acute skin wounds have lately been characterized. We have now investigated the hypothesis that such activities may impact upon the balance between anabolic and catabolic processes during wound healing. We report that wound deposition of both type I collagen and fibronectin is increased in castrated rats compared with control animals. This response is accompanied by early increases and later decreases in overall wound levels of the key collagenolytic enzymes, matrix metalloproteinase (MMP)-1 and MMP-13. Moreover, the activities of MMP-2 and MMP-9, two further enzymes that contribute to collagen digestion during venous ulceration, were significantly decreased in the wounds of castrated rats. Additional analyses provide evidence that androgens directly stimulate dermal fibroblast collagen production, which supports the suggestion that increased wound collagen deposition in androgen-deprived rats results from reduced matrix degradation (as opposed to enhanced matrix protein biosynthesis). Androgen-mediated dysregulation of the parallel processes of collagen deposition and turnover may underscore the delayed healing of cutaneous wounds in elderly male patients and further contribute to the increased incidence of non-healing wounds in this population.

The hormonal regulation of cutaneous wound healing

Conditions of impaired wound healing in the elderly are associated with substantial morbidity and mortality and impose a significant financial burden upon the world's health services. The findings of a series of recent studies have served to highlight the contrasting contributions made by sex steroid hormones to the regulation of cutaneous repair processes. Although estrogens accelerate healing, the actions of the "male" sex hormones 5alpha-dihydrotestosterone and testosterone are primarily deleterious. The shift that occurs in the balance between serum estrogen and androgen levels as a normal feature of human aging may therefore have important consequences for fundamental tissue repair processes.

Prediction and monitoring the therapeutic response of chronic dermal wounds

A significant proportion of chronic wounds fail to heal in response to treatment of underlying pathologies combined with good wound care practice. Current prognostic tests to identify these wounds rely on the use of algorithms based on clinically measurable parameters such as wound dimensions and wound duration. Venous leg ulcers may be stratified into healing/non healing at 24 weeks of compression therapy and diabetic foot ulcer treatment outcome assessed using a 3-parameter algorithm. Accurate and reproducible measurement of wound area is required for these algorithms to have clinical utility. Whilst a number of attempts have been made to develop computerised wound-assessment techniques, wound tracing by clinicians combined with planimetry remains the standard methodology. Once treatment has been initiated, it is important to continuously monitor the wound to assess efficacy of treatment. This can be achieved by measuring wound area change over the first weeks of treatment to identify whether re-assessment of treatment strategy is required. A number of algorithms for assessing rate of wound area change have been evaluated to determine a surrogate endpoint for healing. Retrospective analysis of large patient groups indicates that approximately 75% correct prediction of healing outcome can be achieved.

Mice with a targeted mutation of patched2 are viable but develop alopecia and epidermal hyperplasia

Hedgehog (Hh) signaling plays pivotal roles in tissue patterning and development in Drosophila melanogaster and vertebrates. The Patched1 (Ptc1) gene, encoding the Hh receptor, is mutated in nevoid basal cell carcinoma syndrome, a human genetic disorder associated with developmental abnormalities and increased incidences of basal cell carcinoma (BCC) and medulloblastoma (MB). Ptc1 mutations also occur in sporadic forms of BCC and MB. Mutational studies with mice have verified that Ptc1 is a tumor suppressor. We previously identified a second mammalian Patched gene, Ptc2, and demonstrated its distinct expression pattern during embryogenesis, suggesting a unique role in development. Most notably, Ptc2 is expressed in an overlapping pattern with Shh in the epidermal compartment of developing hair follicles and is highly expressed in the developing limb bud, cerebellum, and testis. Here, we describe the generation and phenotypic analysis of Ptc2(tm1/tm1) mice. Our molecular analysis suggests that Ptc2(tm1) likely represents a hypomorphic allele. Despite the dynamic expression of Ptc2 during embryogenesis, Ptc2(tm1/tm1) mice are viable, fertile, and apparently normal. Interestingly, adult Ptc2(tm1/tm1) male animals develop skin lesions consisting of alopecia, ulceration, and epidermal hyperplasia. While functional compensation by Ptc1 might account for the lack of a strong mutant phenotype in Ptc2-deficient mice, our results suggest that normal Ptc2 function is required for adult skin homeostasis.

Use of ulcer size and initial responses to treatment to predict the healing time of leg ulcers

OBJECTIVE

To test the following two hypotheses: the initial healing profiles of individual leg ulcers determine the longer-term outcome; healing time can be predicted from an initial ulcer size measurement and a sequence of further measurements recorded after treatment has started.

METHOD

Twenty-three patients with venous leg ulcers were studied (10 male, 13 female). Digital images of the ulcers were taken at weekly intervals; ulcer size was measured electronically and the information stored in an electronic patient record. The healing profile for each ulcer was analysed by linear regression using the correlation coefficient (r) to indicate linearity. For [r] > 0.85 ([r] = modulus of r, [where r is negative], that is good linearity and hence wound healing), the predicted healing time was calculated from the initial size (cm2) and initial healing rate (cm2/week), and was compared with the actual healing time.

RESULTS

The majority of ulcers (17/23) healed with linearity ([r] > 0.85). For these ulcers there was agreement between the predicted healing time and the actual healing time (correlation coefficient 0.95).

CONCLUSION

Venous ulcers that respond to treatment appear to heal at a near constant rate. The initial response to treatment can be used to reliably estimate the healing time.

Androgens modulate the inflammatory response during acute wound healing

Impaired wound healing states in the elderly lead to substantial morbidity and mortality, and a cost to the health services of over 9 billion dollars per annum. In addition to intrinsic ageing processes that per se cause delayed healing, studies have suggested marked differences in wound repair between the sexes. We have previously reported that, castration of male mice results in a striking acceleration of local cutaneous wound healing and dampens the associated inflammatory response. In this study, we report that systemic 5alpha-reductase inhibition, which blocks the conversion of testosterone to its more active metabolite 5alpha-dihydrotestosterone, mimics the effects of castration in a rat model of cutaneous wound healing. The mechanisms underlying the observed effects involve a direct, cell-specific upregulation of pro-inflammatory cytokine expression by macrophages, but not fibroblasts, in response to androgens. Androgens require the transforming growth factor beta signalling intermediate Smad3 to be present in order to influence repair and local pro-inflammatory cytokine levels. That reducing 5alpha-dihydrotestosterone levels through 5alpha-reductase antagonism markedly accelerates healing suggests a specific target for future therapeutic intervention in impaired wound healing states in elderly males.

Influence of physiological androgen levels on wound healing and immune status in men

Aging in men is associated with a progressive decline in the production of several hormones, including androgens. The extent to which an age-dependent decline in androgen levels lead to health problems or can affect quality of life remains under debate. Clinical results on replacement therapy do not yet provide a definitive clue on the benefit/risk balance. A sexual dimorphism of the immune system is well established, and the differences between female and male immune responses under normal, as well as pathological, conditions are generally attributed to the influence of estrogens, progestins, and androgens. The suppressive effects of male sex hormones on immune functions have been observed in a wide variety of disease processes and appear to be testosterone-mediated. Endogenous testosterone inhibits skin wound healing response in males and is associated with an enhanced inflammatory response. Although there are no known gender-related differences in permeability barrier function in adults, estrogens accelerates--whereas testosterone retards--barrier development in fetal skin, and male fetuses demonstrate slower barrier development than female littermates.

Prediction of burn healing time using artificial neural networks and reflectance spectrometer

BACKGROUND

Burn depth assessment is important as early excision and grafting is the treatment of choice for deep dermal burn. Inaccurate assessment causes prolonged hospital stay, increased medical expenses and morbidity. Based on reflected burn spectra, we have developed an artificial neural network to predict the burn healing time.

PURPOSE

Our study is to develop a non-invasive objective method to predict burn-healing time.

METHODS AND MATERIALS

Burns less than 20% TBSA was included. Burn spectra taken on the third postburn day using reflectance spectrometer were analyzed by an artificial neural network system.

RESULTS

Forty-one spectra were collected. With the newly developed method, the predictive accuracy of burns healed in less than 14 days was 96%, and that in more than 14 days was 75%.

CONCLUSIONS

Using reflectance spectrometer, we have developed an artificial neural network to determine the burn healing time with 86% overall predictive accuracy.