Fibroblast function and wound breaking strength is impaired by acute ethanol intoxication

Smoking, alcohol consumption and risk of Dupuytren's disease: a Mendelian randomization study

BACKGROUND

The correlation between smoking and alcohol consumption and the development of Dupuytren's disease (DD) has been acknowledged. However, the definitive causal relationship between these two factors and DD remains elusive. In order to establish a causal connection, we employed the two-sample Mendelian randomization method to evaluate the relationship between smoking and alcohol consumption and DD.

METHODS

Based on publicly available genome-wide association studies (GWAS), two-sample univariate MR analyses were performed to assess the causal effects of drinks per week, cigarettes per day, smoking initiation, age of initiation, and smoking cessation on DD. We used inverse variance weighted (IVW) to generate the primary results for the MR analysis. Furthermore, we performed sensitivity MR analyses based on various methods to assess the robustness of estimations. Bidirectional MR analyses were used to study the interaction between smoking and alcohol consumption. Multivariate MR analyses were used to obtain independent causal effects of smoking or drinking on DD.

RESULTS

Our two-sample MR, which was predominately based on IVW, revealed a causal relationship between drinks per week and DD (OR = 2.948, 95%CI: 1.746-4.975, P = 5.16E-05). In addition, there is no causal association between cigarettes per day, smoking initiation, age of initiation, smoking cessation and DD. Similar conclusions were reached by other MR methods. The results of the bidirectional MR analyses showed that the causal relationships between age of initiation and drinks per week were robust and significant. Multivariate MR results indicated that the causal effect of alcohol consumption on DD was independent of smoking.

CONCLUSION

Our Mendelian Randomization study indicated that there is a causality between drinking alcohol and DD, but no such causality was found between smoking and DD. This is the first study to prove that drinking alcohol could cause DD. This could help people who are trying to prevent DD from happening in the first place.

Wound healing dynamics, morbidity, and complications of palatal soft-tissue harvesting

Palatal-tissue harvesting is a routinely performed procedure in periodontal and peri-implant plastic surgery. Over the years, several surgical approaches have been attempted with the aim of obtaining autogenous soft-tissue grafts while minimizing patient morbidity, which is considered the most common drawback of palatal harvesting. At the same time, treatment errors during the procedure may increase not only postoperative discomfort or pain but also the risk of developing other complications, such as injury to the greater palatine artery, prolonged bleeding, wound/flap sloughing, necrosis, infection, and inadequate graft size or quality. This chapter described treatment errors and complications of palatal harvesting techniques, together with approaches for reducing patient morbidity and accelerating donor site wound healing. The role of biologic agents, photobiomodulation therapy, local and systemic factors, and genes implicated in palatal wound healing are also discussed.

Microfibril-associated protein 5 and the regulation of skin scar formation

Many factors regulate scar formation, which yields a modified extracellular matrix (ECM). Among ECM components, microfibril-associated proteins have been minimally explored in the context of skin wound repair. Microfibril-associated protein 5 (MFAP5), a small 25 kD serine and threonine rich microfibril-associated protein, influences microfibril function and modulates major extracellular signaling pathways. Though known to be associated with fibrosis and angiogenesis in certain pathologies, MFAP5's role in wound healing is unknown. Using a murine model of skin wound repair, we found that MFAP5 is significantly expressed during the proliferative and remodeling phases of healing. Analysis of existing single-cell RNA-sequencing data from mouse skin wounds identified two fibroblast subpopulations as the main expressors of MFAP5 during wound healing. Furthermore, neutralization of MFAP5 in healing mouse wounds decreased collagen deposition and refined angiogenesis without altering wound closure. In vitro, recombinant MFAP5 significantly enhanced dermal fibroblast migration, collagen contractility, and expression of pro-fibrotic genes. Additionally, TGF-ß1 increased MFAP5 expression and production in dermal fibroblasts. Our findings suggest that MFAP5 regulates fibroblast function and influences scar formation in healing wounds. Our work demonstrates a previously undescribed role for MFAP5 and suggests that microfibril-associated proteins may be significant modulators of wound healing outcomes and scarring.

Ageing decreases the healing of wounds in the skin of alcohol-preferring rats

OBJECTIVE

Alcohol consumption combined with ageing alters the healing process of the skin. We evaluated whether ageing decreases the healing of incisional wounds in the skin of Wistar rats of Universidade de Chile of variety B (UChB).

METHOD

A total of 20 adult rats and 20 older UChB rats, divided into two groups which underwent surgical aggression in the anterior region of the abdomen, were used: G1, adult rats (100 days old, control) with water and 10% ethanol; G2, aged rats (540 days old, experimental) with water and 10% ethanol; evaluated at 4, 7, 14 and 21 days after surgery.

RESULTS

Ageing did not alter the rupture force and collagen elasticity and resistance. There were increases in telomerase with the implementation of cellular senescence, in interleukin 1-alpha (IL-1α) at 14 days of healing, in epidermal growth factor (EGF) at 14 and 21 days of healing with delayed growth and development of keratinocytes, also an increase of IL-β at 4 days, and decrease in tumour necrosis factor (TNFα) at 7 days, associated with chronic scarring. There was an increase in vascular endothelial growth factor (VEGF) at 4 and 7 days, responsible for the early vessels re-establishment. There was a decrease in transforming growth factor 2-beta (TGFβ2) and β3 at 4 and 7 days of healing respectively, and estradiol at 4 days.

CONCLUSION

Ageing decreases the skin healing in incisional wounds in alcohol-preferring rats.

Factors Associated with Shoulder Range of Motion After Arthroscopic Rotator Cuff Repair: A Hospital‐Based Prospective Study

Objective

To assess the factors associated with outcomes of arthroscopic surgical repair of rotator cuff tears (RCTs).

Method

This prospective study recruited patients, at least 18 years old, who underwent arthroscopic rotator cuff repair for full‐thickness RCTs at the First People's Hospital of Hangzhou Xiaoshan between July 2019 and October 2020. Patient demographics, lifestyle habits, and medical histories were collected preoperatively; RCT sizes and affected tendons were determined intraoperatively. Outcomes were assessed by shoulder range of motion (ROM) determinations 1.5 and 3 months postoperatively. The factors associated with ROM were determined using a binary logistic regression analysis, and the results were expressed as adjusted relative risks (RRs) and 95% confidence intervals (CIs).

Results

A total of 132 patients with RCTs underwent arthroscopic surgery. Five were lost to follow‐up, leaving 127 patients (mean age, 59 years; 58.3% women) who were included in the study analysis. The majority of the patients (54.5%) had RCTs that were classified as large or massive, and approximately 20% had tears involving multiple tendons; 80.3% of the patients had tears involving only a single tendon. Moreover, 29.9% of the patients had hypertension and 11.0% had diabetes. Among the patients, 23.0% were smokers and 34.6% drank alcohol. According to the multivariate analysis, none of the assessed factors were associated with shoulder ROM at the 1.5‐month follow‐up. At the 3‐month follow‐up, RCTs involving a single tendon demonstrated 3‐fold better abduction (RR = 4.00; 95% CI, 1.30–12.33; P = 0.016) and 3.15‐fold better internal rotation (RR = 3.15; 95% CI, 1.19–8.36; P = 0.021) than did RCTs involving multiple tendons. Patients who did not drink alcohol demonstrated 6.08‐fold better anteflexion (RR = 7.08; 95% CI, 2.11–23.73; P = 0.002) and nearly 4‐fold better abduction (RR = 4.97; 95% CI, 1.62–15.23; P = 0.005) than patients who drank alcohol.

Conclusion

To improve outcomes, the results indicate that more targeted measures should be directed toward patients with multiple‐tendon RCTs and that preoperative alcohol abstinence education is needed for patients with RCTs.

Mammalian Target of Rapamycin Inhibitors and Wound Healing Complications in Kidney Transplantation: Old Myths and New Realities

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients' profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods.

Alcohol Withdrawal Is Associated With Worse Outcomes in Patients Undergoing Primary Total Knee or Total Hip Arthroplasty

BACKGROUND

Alcohol withdrawal (AW) syndrome is an independent risk factor for postoperative complications. This study aims to evaluate the influence of AW on perioperative outcomes in patients who underwent primary total knee (TKA) or total hip arthroplasty (THA).

METHODS

We used the National Inpatient Sample database to identify patients undergoing TKA/THA from 2003 to 2014. The primary exposure of interest was AW. Multivariable adjusted models were used to evaluate the association of AW with in-hospital medical complications, surgical complications, mortality, cost, and length of stay (LOS) in patients undergoing TKA/THA.

RESULTS

There were 2,971,539 adult hospitalizations for THAs and 6,367,713 hospitalizations for TKAs included in the present study, among which 0.14% of AW for THA patients and 0.10% of AW for TKA patients. Multivariable adjustment analysis suggested that AW was associated with an increased risk of medical complications (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.79-2.42, P < .0001), surgical complications (OR 1.75, 95% CI 1.51-2.03, P < .0001), and had 4.79 times increase of in-hospital mortality, 26% increase of total cost, and 53% increase of LOS in THA procedures. For TKA procedures, AW was also associated with increased risk of medical complications (OR 3.14, 95% CI 2.78-3.56, P < .0001), surgical complications (OR 2.07, 95% CI 1.82-2.34, P < .0001) and 4.24 times increase of in-hospital mortality, 29% increase of total cost, and 58% increase of LOS after multivariable adjustment.

CONCLUSION

AW is associated with increased risk of in-hospital mortality, medical and surgical complications. Proactive surveillance and management of AW may be important in improving outcomes in patients who underwent THA and TKA procedure.

Wound Healing: A Comprehensive Review

Wound healing is an intricate, tightly regulated process that is critical to maintaining the barrier function of skin along with preserving all other skin functions. This process can be influenced by a variety of modifiable and nonmodifiable factors. As wound healing takes place in all parts of the human body, this review focuses on cutaneous wound healing and highlights the classical wound healing phases. Alterations in any of these phases can promote chronic wound development and may impede wound healing.

Targeting the NLRP3 Inflammasome in Glaucoma

Glaucoma is a group of optic neuropathies characterised by the degeneration of retinal ganglion cells, resulting in damage to the optic nerve head (ONH) and loss of vision in one or both eyes. Increased intraocular pressure (IOP) is one of the major aetiological risk factors in glaucoma, and is currently the only modifiable risk factor. However, 30–40% of glaucoma patients do not present with elevated IOP and still proceed to lose vision. The pathophysiology of glaucoma is therefore not completely understood, and there is a need for the development of IOP-independent neuroprotective therapies to preserve vision. Neuroinflammation has been shown to play a key role in glaucoma and, specifically, the NLRP3 inflammasome, a key driver of inflammation, has recently been implicated. The NLRP3 inflammasome is expressed in the eye and its activation is reported in pre-clinical studies of glaucoma. Activation of the NLRP3 inflammasome results in IL-1β processing. This pro inflammatory cytokine is elevated in the blood of glaucoma patients and is believed to drive neurotoxic inflammation, resulting in axon degeneration and the death of retinal ganglion cells (RGCs). This review discusses glaucoma as an inflammatory disease and evaluates targeting the NLRP3 inflammasome as a therapeutic strategy. A hypothetical mechanism for the action of the NLRP3 inflammasome in glaucoma is presented.

Role of the lysyl oxidase family in organ development (Review)

Lysyl oxidase proteins (LOXs) are amine oxidases, which are mainly located in smooth muscle cells and fibroblasts and serve an important role in the formation of the extracellular matrix (ECM) in a copper-dependent manner. Owing to the ability of LOX proteins to modulate crosslinking between collagens and to promote the deposition of other fibers, they serve crucially in organogenesis and the subsequent organ development, as well as disease initiation and progression. In addition, ECM formation significantly influences organ morphological formation in both cancer- and non-tumor-related diseases, in addition to cellular epigenetic transformation and migration, under the influence of LOXs. A number of different signaling pathways regulate the LOXs expression and their enzymatic activation. The tissue remodeling and transformation process shares some resemblance between oncogenesis and embryogenesis. Additionally the roles that LOXs serve appeared to be stressed during oncogenesis and tumor metastasis. It has also been indicated LOXs have a noteworthy role in non-tumor diseases. Nonetheless, the role of LOXs in systemic or local organ development and disease control remains unknown. In the present study, the essential roles that LOXs play in embryogenesis were unveiled partially, whereas the role of LOXs in organ or systematic development requires further investigations. The present review aimed to discuss the roles of members of the LOX family in the context of the remodeling of organogenesis and organ development. In addition, the consequences of the malfunction of these proteins related to the development of abnormalities and resulting diseases is discussed.

Improvement of full-thickness rat skin wounds by photobiomodulation therapy (PBMT): A dosimetric study

Basic dosimetric studies are necessary to support the use of photobiomodulation therapy (PBMT), since the great variety of laser parameters that are reported in the literature have created an obstacle to identifying reproducible results. Thus, the present study evaluates the process of tissue repair after the photobiomodulation therapy, taking into consideration the dose, frequency and the mode of energy delivery used. For this, 6 mm diameter wounds were created on dorsal skin of Wistar rats, and the animals were divided in control and irradiated groups, where L1 and L4 (irradiated with 1 point of 10 J/cm2), L2 and L5 (5 points of 10 J/cm2), L3 and L6 (1 point of 50 J/cm2), respectively for one or multiple days of irradiations. A diode laser, λ 660 nm, 40 mW of power and 0.028 cm2 of spot area was used. Our data showed that the group receiving multiple treatments over the first week post wounding, applied at 10 J/cm2 at each of 5 points on and around the wound (group L5) presented the best improvement of wound closure, higher cytokeratin 10, lower macrophage infiltration, and greater tissue resistance to rupture. We conclude that PBMT improves the skin wound healing process, and the outcomes were directly related to the chosen laser parameters and irradiation mode.

Predictors of Wound Healing Following Revascularization for Chronic Limb-Threatening Ischemia

OBJECTIVES

After surgical or endovascular revascularization, some ischemic lesions will not heal, while some others will heal at a variable period of time from the intervention, indicating a multifactorial interaction between local and systematic "wound healing-promoting" factors. Our objective was to identify predictors of wound healing following revascularization for chronic limb-threatening ischemia (CLTI).

METHODS

A literature review was performed to identify published research concerning clinical, biochemical, and noninvasive methods as predictors of wound healing time and wound-free period after surgical and endovascular revascularization for CLTI.

RESULTS

Our review indicated that potential predictors included local wound factors, wound depth, patient's comorbidities, medications, smoking and alcohol abuse, poor vessel runoff, and direct versus indirect revascularization. Among the clinical biomarkers, platelet-derived growth factor, transforming growth factor β, basic fibroblast growth factor, tumor necrosis factor α, interleukin (IL) 1, and IL-6 have been proposed as potential predictors. Furthermore, the potential of noninvasive microcirculation assessment to predict proper wound healing has been the topic of extensive investigation. Among the novel methods, transcutaneous measurement of oxygen partial pressure, skin perfusion pressure, oxygen-to-see method, indocyanine green fluorescence imaging, and multispectral optoacoustic tomography have shown promising results.

CONCLUSIONS

The risk factor profile of an ischemic lesion in the lower extremities with a delayed/failed healing response, following a successful revascularization, is not fully clarified. Although many predictors have been assessed so far, further research needs to be done to identify the optimal clinical and biochemical indices and the noninvasive technique assessing the microcirculation that is associated with complete wound healing.

Stain-free LED scanning lifetime imaging system for diabetes modified tissue matrices

In contrast to labor intensive and destructive histological techniques, intrinsic autofluorescence lifetimes of extra cellular matrix proteins can provide label-free imaging of tissue modifications in diseases, including the diabetic ulcers. However, decoupling the complex mixture of tissue fluorophores requires costly and complicated fluorescent lifetime instrumentation. Furthermore, a list of autofluorescent and fluorogenic proteins must be characterized to profile their changes during disease progression. Towards these goals, an imaging system based on frequency domain light-emitting diode (LED) modulation was designed and demonstrated, using off-the-shelf components in a low complexity design. The system was operated by coupling and imaging fluorescence intensities using a pair of objectives. The system's scanning and signal acquisition performances were optimized with respect to etendues. To study fluorescent proteins in diabetic ulcers, lifetimes from purified and pentosidine modified collagen I, collagen III, and elastin were measured. Pentosidine measurements showed a decrease in autofluorescent lifetimes while elevated collagen III in diabetic ulcers showed increased lifetimes. These lifetimes, plus future protein measurements enabled by our system, can serve as standards for developing a biophotonic model of diabetic ulcers. As a proof-of-concept, a 3 cm × 3 cm diabetic foot ulcer was imaged using the developed system. Phasor analysis was applied to aid the interpretation of lifetime images. As a result, a compact biophotonic imaging system targeting diabetic tissue was achieved, towards making the technique accessible for clinical histology.

Pigment Epithelium-Derived Factor (PEDF) as a Regulator of Wound Angiogenesis

Although the inflammatory and proliferative phases of wound healing have been well described, much less is known about how healing resolves. During the resolution phase, pruning of the capillary bed and maturation of capillaries occurs and influences the final strength and fidelity of the wound. PEDF, an endogenous anti-angiogenic factor, is produced in wounds and may contribute to the removal of capillaries during wound resolution. This study utilized PEDF-/- mice to examine how PEDF influences wound angiogenesis, particularly capillary density and permeability. The absence of PEDF led to transient changes in dermal wound closure and collagen content, but caused substantial changes in wound angiogenesis. Compared to wild type (WT) mice, wounds from PEDF-/- mice exhibited a significant increase in capillaries during the proangiogenic phase of repair, and a delay in capillary pruning. Conversely, the addition of rPEDF caused a reduction in capillary density within skin wounds in WT mice. In vitro studies showed that PEDF inhibited migration and tube formation by dermal microvascular endothelial cells, and caused a decrease in the expression of VEGFR2, VCAM-1, and other surface receptors. The results demonstrate that loss of PEDF causes a distinctive wound healing phenotype that is characterized by increased angiogenesis and delayed resolution. The findings suggest that PEDF most likely acts through multiple mechanisms to regulate proper capillary refinement in wounds.

High-Fat Diet and Alcohol Intake Promotes Inflammation and Impairs Skin Wound Healing in Wistar Rats

The wound-healing process is complex and remains a challenging process under the influence of several factors, including eating habits. As improper diets may lead to disorders such as dyslipidemia, insulin resistance, and chronic inflammation, potentially affecting the tissue ability to heal, we decided to investigate the effect of a high-fat diet and alcohol intake on the inflammatory process and skin wound healing in Wistar rats. Male rats (n = 30) were individually housed in cages with food and water ad libitum (registration number 213/2014). After anesthesia, at day 40, three circular wounds (12 mm diameter) were made on the back of each animal, which were then randomly assorted into five treatment groups: C1 (control 1)-water via gavage and standard chow diet; C2 (control 2)-water (no gavage) and standard chow diet; AL (alcohol)-water (no gavage) and alcohol (40%) via gavage and standard chow diet; HF (high fat)-water (no gavage) and high-fat diet (50%); and HF + AL (alcohol/high fat)-water (no gavage), alcohol (40%) via gavage, and high-fat diet. Animals were treated for 61 days. Every seven days, the area and the rate of wound contraction were evaluated. Tissue samples were removed for histopathological analysis and biochemical analyses. Our results showed that wound contraction was not complete in the HF + AL rats. Two specific indices of wound-healing impairment (total cell number and levels of the inflammatory cytokine TGF-β) were increased in the HF + AL rats. We also observed decreased type I and III collagen fibers in the HF, AL, and HF + AL groups and increased oxidative stress markers in the same groups. We suggest that a high-fat diet combined with alcohol intake contributed to delayed skin wound healing through increase of the inflammatory phase and promoting oxidative stress, which may have led to morphological alterations and impaired matrix remodeling.

From Inflammation to Current and Alternative Therapies Involved in Wound Healing

Wound healing is a complex event that develops in three overlapping phases: inflammatory, proliferative, and remodeling. These phases are distinct in function and histological characteristics. However, they depend on the interaction of cytokines, growth factors, chemokines, and chemical mediators from cells to perform regulatory events. In this article, we will review the pathway in the skin healing cascade, relating the major chemical inflammatory mediators, cellular and molecular, as well as demonstrating the local and systemic factors that interfere in healing and disorders associated with tissue repair deficiency. Finally, we will discuss the current therapeutic interventions in the wounds treatment, and the alternative therapies used as promising results in the development of new products with healing potential.

Effect of a high-fat diet and alcohol on cutaneous repair: A systematic review of murine experimental models

BACKGROUND AND PURPOSE

Chronic alcohol intake associated with an inappropriate diet can cause lesions in multiple organs and tissues and complicate the tissue repair process. In a systematic review, we analyzed the relevance of alcohol and high fat consumption to cutaneous and repair, compared the main methodologies used and the most important parameters tested. Preclinical investigations with murine models were assessed to analyze whether the current evidence support clinical trials.

METHODS

The studies were selected from MEDLINE/PubMed and Scopus databases, according to Fig 1. All 15 identified articles had their data extracted. The reporting bias was investigated according to the ARRIVE (Animal Research: Reporting of in Vivo Experiments) strategy.

RESULTS

In general, animals offered a high-fat diet and alcohol showed decreased cutaneous wound closure, delayed skin contraction, chronic inflammation and incomplete re-epithelialization.

CONCLUSION

In further studies, standardized experimental design is needed to establish comparable study groups and advance the overall knowledge background, facilitating data translatability from animal models to human clinical conditions.

Does history of substance use disorder predict acute traumatic brain injury rehabilitation outcomes?

BACKGROUND/OBJECTIVE

The study explored whether premorbid substance use disorder (SUD) predicts acute traumatic brain injury (TBI) outcomes.

METHODS

143 participants with moderate (34.2%) and severe (65.8%) TBI were enrolled at two Level 1 trauma center inpatient brain injury rehabilitation units. Acute outcomes were measured with the Disability Rating Scale (DRS), the FIMTM; self and informant ratings of the Patient Competency Rating Scale (PCRS); self and family rating of the Frontal Systems Behavioral Scale (FrSBe), and the Neurobehavioral Rating Scale-Revised (NRS-R).

RESULTS

Hierarchical linear modeling revealed that SUD history significantly predicted trajectories of PCRS clinician ratings, PCRS self-family and PCRS self-clinician discrepancy scores, and more negative FrSBE family ratings. These findings indicate comparatively greater post-injury executive functions (EF) impairments, particularly self-awareness (SA) of injury-related deficits, for those with SUD history. No significant SUD*time interaction effect was found for FIM or NRS-R scores.

CONCLUSIONS

SUD history and TBI are associated with impaired SA and EF but their co-occurrence is not a consistent predictor of acute post-injury functional outcomes. Pre-morbid patient characteristics and rater expectations and biases may moderate associations between SA and recovery after TBI.

Wound healing in Mac-1 deficient mice

Mac-1 (CD11b/CD18) is a macrophage receptor that plays several critical roles in macrophage recruitment and activation. Because macrophages are essential for proper wound healing, the impact of Mac-1 deficiency on wound healing is of significant interest. Prior studies have shown that Mac-1^-/- mice exhibit deficits in healing, including delayed wound closure in scalp and ear wounds. This study examined whether Mac-1 deficiency influences wound healing in small excisional and incisional skin wounds. Three millimeter diameter full thickness excisional wounds and incisional wounds were prepared on the dorsal skin of Mac-1 deficient (Mac-1^-/- ) and wild type (WT) mice, and wound healing outcomes were examined. Mac-1 deficient mice exhibited a normal rate of wound closure, generally normal levels of total collagen, and nearly normal synthesis and distribution of collagens I and III. In incisional wounds, wound breaking strength was similar for Mac-1^-/- and WT mice. Wounds of Mac-1 deficient mice displayed normal total macrophage content, although macrophage phenotype markers were skewed as compared to WT. Interestingly, amounts of TGF-β1 and its downstream signaling molecules, SMAD2 and SMAD3, were significantly decreased in the wounds of Mac-1 deficient mice compared to WT. The results suggest that Mac-1 deficiency has little impact on the healing of small excisional and incisional wounds. Moreover, the findings demonstrate that the effect of single genetic deficiencies on wound healing may markedly differ among wound models. These conclusions have implications for the interpretation of the many prior studies that utilize a single model system to examine wound healing outcomes in genetically deficient mice.

Protective influence of hyaluronic acid on focal adhesion kinase activity in human skin fibroblasts exposed to ethanol

Aim

The aim of this study was to evaluate the effect of ethanol and hyaluronic acid (HA) on cell survival and apoptosis in cultured human skin fibroblasts. Regarding the mechanism of ethanol action on human skin fibroblasts, we investigated cell viability and apoptosis, expression of focal adhesion kinase (FAK), and the influence of HA on those processes.

Materials and methods

Studies were conducted in confluent human skin fibroblast cultures that were treated with 25 mM, 50 mM, and 100 mM ethanol or with ethanol and 500 µg/mL HA. Cell viability was examined using methyl thiazolyl tetrazolium (MTT) assay and NC-300 Nucleo-Counter. Imaging of the cells using a fluorescence microscope Pathway 855 was performed to measure FAK expression.

Results

Depending on the dosage, ethanol decreased cell viability and activated the process of apoptosis in human skin fibroblasts. HA prevented the negative influence of ethanol on cell viability and prevented apoptosis. The analysis of fluorescence imaging using BD Pathway 855 High-Content Bioimager showed the inhibition of FAK migration to the cell nucleus, depending on the increasing concentration of ethanol.

Conclusion

This study proves that downregulation of signaling pathway of FAK is involved in ethanol-induced apoptosis in human skin fibroblasts. The work also indicates a protective influence of HA on FAK activity in human skin fibroblasts exposed to ethanol.

The Role of the Lysyl Oxidases in Tissue Repair and Remodeling: A Concise Review

Tissue injury provokes a series of events containing inflammation, new tissue formation and tissue remodeling which are regulated by the spatially and temporally coordinated organization. It is an evolutionarily conserved, multi-cellular, multi-molecular process via complex signalling network. Tissue injury disorders present grievous clinical problems and are likely to increase since they are generally associated with the prevailing diseases such as diabetes, hypertension and obesity. Although these dynamic responses vary not only for the different types of trauma but also for the different organs, a balancing act between the tissue degradation and tissue synthesis is the same. In this process, the degradation of old extracellular matrix (ECM) elements and new ones' synthesis and deposition play an essential role, especially collagens. Lysyl oxidase (LOX) and four lysyl oxidase-like proteins are a group of enzymes capable of catalyzing cross-linking reaction of collagen and elastin, thus initiating the formation of covalent cross-links that insolubilize ECM proteins. In this way, LOX facilitates ECM stabilization through ECM formation, development, maturation and remodeling. This ability determines its potential role in tissue repair and regeneration. In this review, based on the current in vitro, animal and human in vivo studies which have shown the significant role of the LOXs in tissue repair, e.g., tendon regeneration, ligament healing, cutaneous wound healing, and cartilage remodeling, we focused on the role of the LOXs in inflammation phase, proliferation phase, and tissue remodeling phase of the repair process. By summarizing its healing role, we hope to shed light on the understanding of its potential in tissue repair and provide up to date therapeutic strategies towards related injuries.

Adamts1 mediates ethanol-induced alterations in collagen and elastin via a FoxO1-sestrin3-AMPK signaling cascade in myocytes

A variety of stressors including alcohol (EtOH) are known to induce collagen production and fibrotic diseases. Matrix metalloproteinases (MMP) play an important role in regulating fibrosis, but little is known regarding the relationship between EtOH and MMPs. In addition, the signaling cascades involved in this process have not been elucidated. We have identified the MMP Adamts1 as a target of EtOH regulation. To characterize the function of Adamts1, we examined EtOH-induced alterations in collagen I and elastin protein levels in C2C12 myocytes. Incubation of myocytes with 100 mM EtOH decreased elastin and increased collagen content, respectively, and these changes were associated with increased O-GLcNAc modification of Adamts1. Conversely, silencing of Adamts1 by siRNA blocked the adverse effects of EtOH on collagen and elastin levels. Similar results were obtained after treatment with a pharmacological inhibitor of MMP. Changes in collagen were due, at least in part, to a decreased interaction of Adamts1 with its endogenous inhibitor TIMP3. The AMPK inhibitor compound C blocked the EtOH-induced stimulation of collagen and O-GLcNAc Adamts1 protein. Changes in AMPK appear linked to FoxO1, since inhibition of FoxO1 blocked the effects of EtOH on AMPK phosphorylation and O-GLcNAc levels. These FoxO-dependent modifications were associated with an upregulation of the FoxO1 transcription target sestrin 3, as well as increased binding of sestrin 3 with AMPK. Collectively, these data indicate that EtOH regulates the collagen I and elastin content in an Adamts1-dependent manner in myocytes. Furthermore, Adamts1 appears to be controlled by the FoxO1-sestrin 3-AMPK signaling cascade.

Aberrant Wound Healing in an Epidermal Interleukin-4 Transgenic Mouse Model of Atopic Dermatitis

Wound healing in a pre-existing Th2-dominated skin milieu was assessed by using an epidermal specific interleukin-4 (IL-4) transgenic (Tg) mouse model, which develops a pruritic inflammatory skin condition resembling human atopic dermatitis. Our results demonstrated that IL-4 Tg mice had delayed wound closure and re-epithelialization even though these mice exhibited higher degrees of epithelial cell proliferation. Wounds in IL-4 Tg mice also showed a marked enhancement in expression of inflammatory cytokines/chemokines, elevated infiltration of inflammatory cells including neutrophils, macrophages, CD3+ lymphocytes, and epidermal dendritic T lymphocytes. In addition, these mice exhibited a significantly higher level of angiogenesis as compared to wild type mice. Furthermore, wounds in IL-4 Tg mice presented with larger amounts of granulation tissue, but had less expression and deposition of collagen. Taken together, an inflamed skin condition induced by IL-4 has a pronounced negative influence on the healing process. Understanding more about the pathogenesis of wound healing in a Th2- dominated environment may help investigators explore new potential therapeutic strategies.

Hyaluronic acid abrogates ethanol-dependent inhibition of collagen biosynthesis in cultured human fibroblasts

Introduction

The aim of the study was to evaluate the effect of ethanol on collagen biosynthesis in cultured human skin fibroblasts, and the role of hyaluronic acid (HA) in this process. Regarding the mechanism of ethanol action on human skin fibroblasts we investigated: expression of β₁ integrin and insulin-like growth factor 1 receptor (IGF-IR), signaling pathway protein expression: mitogen-activated protein kinases (MAPKs), protein kinase B (Akt), nuclear factor kappa B (NF-κB) transcription factor, cytotoxicity assay and apoptosis, metalloproteinase activity, as well as the influence of HA on these processes.

Materials and methods

Collagen biosynthesis, activity of prolidase, DNA biosynthesis, and cytotoxicity were measured in confluent human skin fibroblast cultures that have been treated with 25, 50, and 100 mM ethanol and with ethanol and 500 µg/mL HA. Western blot analysis and zymography were performed to evaluate expression of collagen type I, β₁ integrin receptor, IGF-IR, NF-κB protein, phospho-Akt protein, kinase MAPK, caspase 9 activity, and matrix metalloproteinases (MMP-9 and MMP-2).

Results

Ethanol in a dose-dependent manner lead to the impairment of collagen biosynthesis in fibroblast cultures through decreasing prolidase activity and expression of β₁ integrin and IGF-IR. This was accompanied by an increased cytotoxicity, apoptosis and lowered expression of the signaling pathway proteins induced by β₁ integrin and IGF-IR, that is, MAPK (ERK_1/2) kinases. The lowered amount of synthesized collagen and prolidase activity disturbance may also be due to the activation of NF-κB transcription factor, which inhibits collagen gene expression. It suggests that the decrease in fibroblast collagen production may be caused by the disturbance in its biosynthesis but not degradation. The application of HA has a protective effect on disturbances caused by the examined substances. It seems that regulatory mechanism of ethanol-induced collagen aberration take place at the level of collagen biosynthesis, since no effect of ethanol and HA was found on process of collagen degradation by MMP-2 and MMP-9.

Conclusion

This study provides evidence that ethanol impairs collagen metabolism in human skin fibroblasts, leading to a significant decrease in the amount of produced protein. This mechanism probably is due to downregulation of prolidase activity, expression of β₁ integrin and IGF-IR receptors, and the signaling pathway proteins induced by these receptors.

Secreted biofilm factors adversely affect cellular wound healing responses in vitro

Although most chronic wounds possess an underlying pathology, infectious agents also contribute. In many instances, pathogens exist as biofilms forming clusters surrounded by a secreted extracellular substance. We hypothesized that compounds secreted by biofilm bacteria may inhibit normal wound healing events including cell proliferation and migration. Conditioned media from two common bacterial species associated with chronic skin wounds and chronic tympanic membrane perforations, Staphylococcus aureus and Pseudomonas aeruginosa, were evaluated for their capacity to affect keratinocyte proliferation and migration. Additionally, proteomic analysis was performed to identify proteins within the biofilm conditioned media that may contribute to these observed effects. Biofilm conditioned media from both species inhibited proliferation in human tympanic membrane derived keratinocytes, whereas only biofilm conditioned media from S. aureus inhibited migration. Human epidermal keratinocytes were found to be more sensitive to the effects of the conditioned media resulting in high levels of cell death. Heat treatment and microfiltration suggested that S. aureus activity was due to a protein, while P. aeruginosa activity was more likely due to a small molecule. Proteomic analysis identified several proteins with putative links to delayed wound healing. These include alpha hemolysin, alcohol dehydrogenase, fructose-bisphosphate aldolase, lactate dehydrogenase and epidermal cell differentiation inhibitor.

Alcohol Use As a Risk Factor in Infections and Healing: A Clinician's Perspective

Physicians have recognized for more than a century that alcohol use is associated with infections and that alcoholics are especially at risk for pneumonia. Clear evidence now indicates that alcohol has a systemic effect on every organ. This review first presents a clinical case to describe a patient with immunity issues complicated by alcohol use-a setting familiar to many clinicians. This is followed by a description of the molecular mechanisms that explain the secondary immune deficiency produced by alcohol in the host, focusing mostly on the gut and lower respiratory mucosal immunity. The goal of this review is to increase awareness of the new mechanisms being investigated to understand how alcohol affects the human immune system and the development of new strategies to attenuate adverse outcomes in the affected population.

Hip fractures and chronic alcohol excess: a series of 7,023 cases

We aim to compare trends in characteristics and outcomes for 131 patients with evidence of excess alcohol intake at the time of admission with a hip fracture against 6,892 hip fracture patients with no evidence of alcohol excess. Alcohol excess was determined by a finding of abnormal liver function tests in association with a history of excessive alcohol consumption. Patients who consumed excess alcohol were younger (64 versus 80 years mean age), more likely to be male (47% versus 22%), smoke cigarettes (54% versus 11%), be more mobile and less likely to use a walking aid (28% versus 46%). They were also more likely to sustain an extracapsular fracture (53% versus 39%) and to be living in their own homes at the time of injury (85% versus 66%). Hypertension and cardiac disease were less common in those with alcohol excess. Postoperatively those with alcohol abuse had a shorter hospital stay (mean nine days versus 16 days) but were at a greater risk of developing deep wound infections (2.3% versus 0.6%). For those patients who sustained intracapsular fractures treated by internal fixation there was an increased risk of fracture non-union occurring (29% versus 16%) but there were no other differences in operative complications.

Absence of CD4 or CD8 lymphocytes changes infiltration of inflammatory cells and profiles of cytokine expression in skin wounds, but does not impair healing

The involvement of lymphocytes in skin wound healing has not been studied extensively. This study shows that CD4 and CD8 cells are present in significant numbers in skin wounds with peak levels at days 5-10 and 7-10, respectively. Both subsets expressed inflammatory and/or regulatory cytokines. To examine the function of CD4 and CD8 lymphocytes in tissue repair, wound healing was examined in mice deficient for either CD4 or CD8 cells. Wounds in CD4 deficient mice exhibited an initial delayed infiltration of CD8 cells followed by a relative increase in CD8 cells at day 10 and thereafter. Wounds in CD4 deficient mice also displayed up-regulated expression of IL1β, IL-6, IL-17, IFN-γ, CXCL-1 and down-regulated expression of IL-4 as compared to wild-type mice. In contrast, wounds in CD8 deficient mice showed significantly decreased infiltration of CD4+ cells, neutrophils, and macrophages along with down-regulated expression of IL1β, IL-6, TNF-α, CXCL-1, CCL-2 and up-regulated expression of IL-4 as compared to wild-type mice. Despite these significant changes in cytokine expression and inflammatory cell infiltrate, the rate of wound closure, wound breaking strength, collagen content and angiogenesis in either CD4 or CD8 deficiency showed no significant difference from that of wild-type mice. The results suggest that, despite being present and involved in wound inflammation, neither CD4+ nor CD8+ cells play critical roles in the healing process of skin wounds. Further studies are needed to investigate whether these cells might play critical roles in wounds that experience stress such as ischemia or infection.

Maresin-like lipid mediators are produced by leukocytes and platelets and rescue reparative function of diabetes-impaired macrophages

Nonhealing diabetic wounds are associated with impaired macrophage (Mf) function. Leukocytes and platelets (PLT) play crucial roles in wound healing by poorly understood mechanisms. Here we report the identification and characterization of the maresin-like(L) mediators 14,22-dihydroxy-docosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acids, 14S,22-diHDHA (maresin-L1), and 14R,22-diHDHA (maresin-L2) that are produced by leukocytes and PLT and involved in wound healing. We show that 12-lipoxygenase-initiated 14S-hydroxylation or cytochrome P450 catalyzed 14R-hydroxylation and P450-initiated ω(22)-hydroxylation are required for maresin-L biosynthesis. Maresin-L treatment restores reparative functions of diabetic Mfs, suggesting that maresin-Ls act as autocrine/paracrine factors responsible for, at least in part, the reparative functions of leukocytes and PLT in wounds. Additionally, maresin-L ameliorates Mf inflammatory activation and has the potential to suppress the chronic inflammation in diabetic wounds caused by activation of Mfs. These findings provide initial insights into maresin-L biosynthesis and mechanism of action and potentially offer a therapeutic option for better treatment of diabetic wounds.

The effect of vitamin A and vitamin C on postoperative adhesion formation: A rat model study

BACKGROUND

The aim of this study is to investigate the effect of vitamin A and C, as the agents that improve wound healing, on the adhesion formation process.

MATERIALS AND METHODS

Sixty male Wistar rats were used. They underwent midline laparotomy, for repair of a peritoneal injury, and were then assigned to four groups. Group 1 (Vitamin A) received 2000 units/kg intramuscular injection of vitamin A daily, post surgery, for two weeks; Group 2 (Vitamin C) received 100 mg/kg oral vitamin C daily, after laparotomy, for two weeks; Group 3 (vitamins A and C) received 2000 units/kg intramuscular injection of vitamin A and 100 mg/kg oral vitamin C daily, after laparotomy, for two weeks, and Group four (Sham) rats did not receive any drugs. The adhesion, inflammation, fibrosis scores, and wound integrity were evaluated after two weeks.

RESULTS

Rats in the vitamin C group had the lowest mean adhesion formation score (1 ± 0.27) and the values of p were < 0.0001 for the vitamin A group and vitamin A and C groups and 0.003 for the sham group. Vitamin C also had the lowest fibrosis score (0.50 ± 0.17) among the study groups and the values of p were < 0.0001 for the vitamin A group and vitamin A and C groups and 0.002 for the sham group. The mean inflammation score did not differ significantly among the study groups. The wound disruption strength was the highest in the vitamin C group and the difference was statistically significant in the sham group (1188.69 ± 281.92 vs. 893.04 ± 187.46, p : 0.003).

CONCLUSION

Administration of oral vitamin C reduces adhesion formation and improves wound healing.

Activation of cardiac fibroblasts by ethanol is blocked by TGF-β inhibition

BACKGROUND

Alcohol abuse is the second leading cause of dilated cardiomyopathy, a disorder specifically referred to as alcoholic cardiomyopathy (ACM). Rodent and human studies have revealed cardiac fibrosis to be a consequence of ACM, and prior studies by this laboratory have associated this occurrence with elevated transforming growth factor-beta (TGF-β) and activated fibroblasts (myofibroblasts). To date, there have been no other studies to investigate the direct effect of alcohol on the cardiac fibroblast.

METHODS

Primary rat cardiac fibroblasts were cultured in the presence of ethanol (EtOH) and assayed for fibroblast activation by collagen gel contraction, alpha-smooth muscle actin (α-SMA) expression, migration, proliferation, apoptosis, collagen I and III, and TGF-β expression. The TGF-β receptor type 1 inhibitor compound SB 431542 and a soluble recombinant TGF-βII receptor (RbII) were used to assess the role of TGF-β in the response of cardiac fibroblasts to EtOH.

RESULTS

Treatment for cardiac fibroblasts with EtOH at concentrations of 100 mg/dl or higher resulted in fibroblast activation and fibrogenic activity after 24 hours including an increase in contraction, α-SMA expression, migration, and expression of collagen I and TGF-β. No changes in fibroblast proliferation or apoptosis were observed. Inhibition of TGF-β by SB 431542 and RbII attenuated the EtOH-induced fibroblast activation.

CONCLUSIONS

EtOH treatment directly promotes cardiac fibroblast activation by stimulating TGF-β release from fibroblasts. Inhibiting the action of TGF-β decreases the fibrogenic effect induced by EtOH treatment. The results of this study support TGF-β to be an important component in cardiac fibrosis induced by exposure to EtOH.

Factors That Impair Wound Healing

The body's response to tissue injury in a healthy individual is an intricate, sequential physiologic process that results in timely healing with full re-epithelialization, resolution of drainage, and return of function to the affected tissue. Chronic wounds, however, do not follow this sequence of events and can challenge the most experienced clinician if the underlying factors that are impairing wound healing are not identified. The purpose of this article is to present recent information about factors that impair wound healing with the underlying pathophysiological mechanism that interferes with the response to tissue injury. These factors include co-morbidities (diabetes, obesity, protein energy malnutrition), medications (steroids, non-steroidal anti-inflammatory drugs or NSAIDs, anti-rejection medications), oncology interventions (radiation, chemotherapy), and life style habits (smoking, alcohol abuse). Successful treatment of any chronic wound depends upon identification and management of the factors for each individual.