Gender affects skin wound healing in plasminogen deficient mice

Gas Plasma Exposure Alters Microcirculation and Inflammation during Wound Healing in a Diabetic Mouse Model

Diabetes can disrupt physiological wound healing, caused by decreased levels or impaired activity of angiogenic factors. This can contribute to chronic inflammation, poor formation of new blood vessels, and delayed re-epithelialization. The present study describes the preclinical application of medical gas plasma to treat a dermal, full-thickness ear wound in streptozotocin (STZ)-induced diabetic mice. Gas plasma-mediated effects occurred in both sexes but with gender-specific differences. Hyperspectral imaging demonstrated gas plasma therapy changing microcirculatory parameters, particularly oxygen saturation levels during wound healing, presumably due to the gas plasma's tissue delivery of reactive species and other bioactive components. In addition, gas plasma treatment significantly affected cell adhesion by regulating focal adhesion kinase and vinculin, which is important in maintaining skin barrier function by regulating syndecan expression and increasing re-epithelialization. An anticipated stimulation of blood vessel formation was detected via transcriptional and translational increase of angiogenic factors in gas plasma-exposed wound tissue. Moreover, gas plasma treatment significantly affected inflammation by modulating systemic growth factors and cytokine levels. The presented findings may help explain the mode of action of successful clinical plasma therapy of wounds of diabetic patients.

Sex-dimorphic expression of extracellular matrix genes in mouse bone marrow neutrophils

The mammalian innate immune system is sex-dimorphic. Neutrophils are the most abundant leukocyte in humans and represent innate immunity's first line of defense. We previously found that primary mouse bone marrow neutrophils show widespread sex-dimorphism throughout life, including at the transcriptional level. Extracellular matrix [ECM]-related terms were observed among the top sex-dimorphic genes. Since the ECM is emerging as an important regulator of innate immune responses, we sought to further investigate the transcriptomic profile of primary mouse bone marrow neutrophils at both the bulk and single-cell level to understand how biological sex may influence ECM component expression in neutrophils throughout life. Here, using curated gene lists of ECM components and unbiased weighted gene co-expression network analysis [WGCNA], we find that multiple ECM-related gene sets show widespread female-bias in expression in primary mouse neutrophils. Since many immune-related diseases (e.g., rheumatoid arthritis) are more prevalent in females, our work may provide insights into the pathogenesis of sex-dimorphic inflammatory diseases.

Sex-dimorphic expression of extracellular matrix genes in mouse bone marrow neutrophils

The mammalian innate immune system is sex-dimorphic. Neutrophils are the most abundant leukocyte in humans and represent innate immunity's first line of defense. We previously found that primary mouse bone marrow neutrophils show widespread sex-dimorphism throughout life, including at the transcriptional level. Extracellular matrix [ECM]-related terms were observed among the top sex-dimorphic genes. Since the ECM is emerging as an important regulator of innate immune responses, we sought to further investigate the transcriptomic profile of primary mouse bone marrow neutrophils at both the bulk and single-cell level to understand how biological sex may influence ECM component expression in neutrophils throughout life. Here, using curated gene lists of ECM components and unbiased weighted gene co-expression network analysis [WGCNA], we find that multiple ECM-related gene sets show widespread female-bias in expression in primary mouse neutrophils. Since many immune-related diseases (e.g., rheumatoid arthritis) are more prevalent in females, our work may provide insights into the pathogenesis of sex-dimorphic inflammatory diseases.

Alginate-Based Materials Loaded with Nanoparticles in Wound Healing

Alginate is a naturally derived polysaccharide widely applied in drug delivery, as well as regenerative medicine, tissue engineering and wound care. Due to its excellent biocompatibility, low toxicity, and the ability to absorb a high amount of exudate, it is widely used in modern wound dressings. Numerous studies indicate that alginate applied in wound care can be enhanced with the incorporation of nanoparticles, revealing additional properties beneficial in the healing process. Among the most extensively explored materials, composite dressings with alginate loaded with antimicrobial inorganic nanoparticles can be mentioned. However, other types of nanoparticles with antibiotics, growth factors, and other active ingredients are also investigated. This review article focuses on the most recent findings regarding novel alginate-based materials loaded with nanoparticles and their applicability as wound dressings, with special attention paid to the materials of potential use in the treatment of chronic wounds.

Matrix remodeling associated 7 proteins promote cutaneous wound healing through vimentin in coordinating fibroblast functions

Wound healing depends largely on the remodeling of the extracellular matrix around and reorganization of tissue-resident cells. Matrix remodeling associated 7 (MXRA7) is a member of the matrix remodeling-associated gene family and is involved in matrix remodeling-associated processes, such as inflammatory neovascularization, liver injury, and autoimmune skin disease. To investigate whether and how MXRA7 participate in cutaneous wound healing, an ear-punching model was utilized in wild-type (WT) and MXRA7-deficient mice, and the dermal fibroblasts from these mice were further studied in vitro. Results showed that the MXRA7 deficiency impaired the wound healing process in mice. Quantitative PCR indicated that lack of MXRA7 impaired the expression of several extracellular matrix genes (e.g., MMP-2) and inhibited signaling pathways (e.g., STAT3) in healing ear tissues. In in vitro culture system, migration, contraction, or proliferation of fibroblasts was impaired upon MXRA7 deficiency. Pull-down and mass spectrum assay revealed that vimentin was among the proteins that bound MXRA7 proteins in cells, and further investigations indicate MXRA7 was an autocrine factor in fibroblasts that involved vimentin in certain ways, such as JNK and STAT3/STAT5 signaling pathways in our study. In conclusion, MXRA7 proteins promote wound healing through vimentin in coordinating fibroblast functions.

Sex Hormones, Growth Hormone, and the Cornea

The growth and maintenance of nearly every tissue in the body is influenced by systemic hormones during embryonic development through puberty and into adulthood. Of the ~130 different hormones expressed in the human body, steroid hormones and peptide hormones are highly abundant in circulation and are known to regulate anabolic processes and wound healing in a tissue-dependent manner. Of interest, differential levels of sex hormones have been associated with ocular pathologies, including dry eye disease and keratoconus. In this review, we discuss key studies that have revealed a role for androgens and estrogens in the cornea with focus on ocular surface homeostasis, wound healing, and stromal thickness. We also review studies of human growth hormone and insulin growth factor-1 in influencing ocular growth and epithelial regeneration. While it is unclear if endogenous hormones contribute to differential corneal wound healing in common animal models, the abundance of evidence suggests that systemic hormone levels, as a function of age, should be considered as an experimental variable in studies of corneal health and disease.

Klebsiella pneumoniae enolase-like membrane protein interacts with human plasminogen

Many models assessing the risk of sepsis utilize the knowledge of the constituents of the plasminogen system, as it is proven that some species of bacteria can activate plasminogen, as a result of interactions with bacterial outer membrane proteins. However, much is yet to be discovered about this interaction since there is little information regarding some bacterial species. This study is aimed to check if Klebsiella pneumoniae, one of the major factors of nosocomial pneumonia and a factor for severe sepsis, has the ability to bind to human plasminogen. The strain used in this study, PCM 2713, acted as a typical representative of the species. With use of various methods, including: electron microscopy, 2-dimensional electrophoresis, immunoblotting and peptide fragmentation fingerprinting, it is shown that Klebsiella pneumoniae binds to human plasminogen, among others, due to plasminogen-bacterial enolase-like protein interaction, occurring on the outer membrane of the bacterium. Moreover, the study reveals, that other proteins, such as: phosphoglucomutase, and phosphoenolpyruvate carboxykinase act as putative plasminogen-binding factors. These information may virtually act as a foundation for future studies investigating: the: pathogenicity of Klebsiella pneumoniae and means for prevention from the outcomes of Klebsiella-derived sepsis.

Investigating Epidermal Interactions Through an In Vivo Cutaneous Wound-Healing Assay

Cutaneous wound healing is an intricate and multifaceted process. Despite these complexities, the distinct phases of wound healing provide a unique opportunity to evaluate the roles of different targets in these coordinated responses. This protocol details an in vivo wound healing assay to study the intersection of cellular, molecular, and systemic effector pathways. The role of certain proteins in the wound healing process can be efficiently explored in vivo through the generation of tissue-specific deficient mice. This approach, although optimized for use with animal models displaying epithelial deficiencies, can be used for other tissue-specific deficiencies, and utilizes simple and cost-effective methods, allowing investigators to precisely devise their experimental design. The coordination of immunological, epithelial, vascular, and microenvironmental factors in wound healing makes this technique a valuable tool for investigators across fields.

Biomimetic and estrogenic fibers promote tissue repair in mice and human skin via estrogen receptor β

The dynamic changes in estrogen levels throughout aging and during the menstrual cycle influence wound healing. Elevated estrogen levels during the pre-ovulation phase accelerate tissue repair, whereas reduced estrogen levels in post-menopausal women lead to slow healing. Although previous reports have shown that estrogen may potentiate healing by triggering the estrogen receptor (ER)-β signaling pathway, its binding to ER-α has been associated with severe collateral effects and has therefore limited its use as a therapeutic agent. To this end, soy phytoestrogens, which preferentially bind to the ER-β, are currently being explored as a safer therapeutic alternative to estrogen. However, the development and evaluation of phytoestrogen-based materials as local ER-β modulators remains largely unexplored. Here, we engineered biomimetic and estrogenic nanofiber wound dressings built from soy protein isolate (SPI) and hyaluronic acid (HA) using immersion rotary jet spinning. These engineered scaffolds were shown to successfully recapitulate the native dermal architecture, while delivering an ER-β-triggering phytoestrogen (genistein). When tested in ovariectomized mouse and ex vivo human skin tissues, HA/SPI scaffolds outperformed controls (no treatment or HA only scaffolds) towards promoting cutaneous tissue repair. These improved healing outcomes were prevented when the ER-β pathway was genetically or chemically inhibited. Our findings suggest that estrogenic fibrous scaffolds facilitate skin repair by ER-β activation.

Advantages in Wound Healing Process in Female Mice Require Upregulation A2A-Mediated Angiogenesis under the Stimulation of 17β-Estradiol

Estrogenic steroids and adenosine A_2A receptors promote the wound healing and angiogenesis processes. However, so far, it is unclear whether estrogen may regulate the expression and pro-angiogenic activity of A_2A receptors. Using in vivo analyses, we showed that female wild type (WT) mice have a more rapid wound healing process than female or male A_2A-deficient mice (A_2AKO) mice. We also found that pulmonary endothelial cells (mPEC) isolated from female WT mice showed higher expression of A_2A receptor than mPEC from male WT mice. mPEC from female WT mice were more sensitive to A_2A-mediated pro-angiogenic response, suggesting an ER and A_2A crosstalk, which was confirmed using cells isolated from A_2AKO. In those female cells, 17β-estradiol potentiated A_2A-mediated cell proliferation, an effect that was inhibited by selective antagonists of estrogen receptors (ER), ERα, and ERβ. Therefore, estrogen regulates the expression and/or pro-angiogenic activity of A_2A adenosine receptors, likely involving activation of ERα and ERβ receptors. Sexual dimorphism in wound healing observed in the A_2AKO mice process reinforces the functional crosstalk between ER and A_2A receptors.

Copper-Eluting Fibers for Enhanced Tissue Sealing and Repair

Copper ions play an important role in several physiological processes, including angiogenesis, growth factor induction and extracellular matrix remodeling, that modulate wound healing and tissue repair. In this work, copper-loaded alginate fibers were generated and used as surgical sutures for repair of incisional wounds in live mice. Approximately 95% of initially loaded copper ions were released from the sutures within the first 24 h following an initial burst release. This localized delivery of copper at the incision site resulted in significantly higher recovery in tissue biomechanical strengths compared to conventional nylon and calcium alginate sutures at early times following surgery. Irradiation of copper alginate sutures with near-infrared light resulted in a robust photothermal response and led to efficacies similar to those seen with nonirradiated sutures. Histopathology and immunohistological analyses indicated significantly reduced epithelial gap and higher number of CD31⁺ cells, which is indicative of increased angiogenesis around the incision site. Delivery of copper ions did not result in toxicity under the conditions employed. Our findings demonstrate that delivery of ionic copper from sutures resulted in efficacious approximation and healing of incisional wounds, and copper-eluting fibers may have translational potential for accelerating repair in surgical and trauma wounds.

Cutaneous wound healing in aged, high fat diet-induced obese female or male C57BL/6 mice

Since there are limited studies analyzing the impact of age, sex and obesity on cutaneous repair, the current study evaluated excisional skin wound healing as a function of age, sex and diet in C57BL/6 mice subjected to either low (LFD) or high (HFD) fat diet. Older mice accumulated increased body fat relative to younger mice under HFD. Skin wound healing at particular stages was affected by age in the aspect of Tgfβ-1, MCP-1, Mmp-9 and Mmp-13 expression. The most profound, cumulative effect was observed for the combination of two parameters: age and sex. While skin of younger males displayed extremely high collagen 1 and collagen 3 expression, younger females showed exceptionally high Mmp-13 expression at day 3 and 7 after injury. Diet as a single variable modified the thickness of dermis due to increased dermal White Adipose Tissue (dWAT) accumulation in mice fed HFD. The combination of age and diet affected the re-epithelialization and inflammatory response of injured skin. Overall, our data indicate that age has the most fundamental impact although all components (age, sex and diet) contribute to skin repair.

Sex-specific metabolic and functional differences in human umbilical vein endothelial cells from twin pairs

BACKGROUND AND AIMS

Gonadal hormones are mainly thought to account for sex and gender differences in the incidence, clinical manifestation and therapy of many cardiovascular diseases. However, intrinsic sex differences at the cellular level are mostly overlooked. Here, we assessed sex-specific metabolic and functional differences between male and female human umbilical vein endothelial cells (HUVECs).

METHODS

Cellular metabolism was investigated by bioenergetic studies (Seahorse Analyser) and a metabolomic approach. Protein levels were determined by Western blots and proteome analysis. Vascular endothelial growth factor (VEGF)-stimulated cellular migration was assessed by gap closure. HUVECs from dizygotic twin pairs were used for most experiments.

RESULTS

No sex differences were observed in untreated cells. However, sexual dimorphisms appeared after stressing the cells by serum starvation and treatment with VEGF. Under both conditions, female cells had higher intracellular ATP and metabolite levels. A significant decline in ATP levels was observed in male cells after serum starvation. After VEGF, the ratio of glycolysis/mitochondrial respiration was higher in female cells and migration was more pronounced.

CONCLUSIONS

These results point to an increased stress tolerance of female cells. We therefore propose that female cells have an energetic advantage over male cells under conditions of diminished nutrient supply. A more favourable energy balance of female HUVECs after serum starvation and VEGF could potentially explain their stronger migratory capacity.

Nrf2 signaling and inflammation are key events in physical plasma-spurred wound healing

Wound healing is strongly associated with the presence of a balanced content of reactive species in which oxygen-dependent, redox-sensitive signaling represents an essential step in the healing cascade. Numerous studies have demonstrated that cold physical plasma supports wound healing due to its ability to deliver a beneficial mixture of reactive species directly to the cells.

Methods: We described a preclinical proof-of-principle-concept of cold plasma use in a dermal, full-thickness wound model in immunocompetent SKH1 mice. Quantitative PCR, Western blot analysis, immunohistochemistry and immunofluorescence were perfomed to evaluate the expression and cellular translocation of essential targets of Nrf2 and p53 signaling as well as immunomodulatory and angiogenetic factors. Apoptosis and proliferation were detected using TUNEL assay and Ki67 staining, respectively. Cytokine levels in serum were measured using bead-based multiplex cytokine analysis. Epidermal keratinocytes and dermal fibroblasts were isolated from mouse skin to perform functional knockdown experiments. Intravital fluorescence analysis was used to illustrate and quantified microvascular features.

Results: Plasma exerted significant effects on wound healing in mice, including the promotion of granulation and reepithelialization as a consequence of the migration of skin cells, the balance of antioxidant and inflammatory response, and the early induction of macrophage and neutrophil recruitment to the wound sites. Moreover, through an early and local plasma-induced p53 inhibition with a concomitant stimulation of proliferation, the upregulation of angiogenetic factors, and an increased outgrowth of new vessels, our findings explain why dermal skin repair is accelerated. The cellular redox homeostasis was maintained and cells were defended from damage by a strong modulation of the nuclear E2-related factor (Nrf2) pathway and redox-sensitive p53 signaling.

Conclusions: Although acute wound healing is non-problematic, the pathways highlighted that mainly the activation of Nrf2 signaling is a promising strategy for the clinical use of cold plasma in chronic wound healing.

Patient Risk Factors for Mechanical Wound Complications and Postoperative Infections after Elective Open Intestinal Resection

BACKGROUND

Few studies focused on the construction of preoperative patient surgical risk profile using only patients' personal, social history, and comorbidity profiles.

OBJECTIVE

To identify risk factors for mechanical wound complications and postoperative infections in patients' preoperative profiles.

DESIGN

Quantitative retrospective cohort study using 2009-2011 Health Care Utilization Project (HCUP) Nationwide Inpatient Sample (NIS) databases.

PATIENTS

56,853 patients who underwent elective open intestinal resection.

MEASUREMENTS

Predictors of mechanical wound complications and postoperative infections in patients' personal, social history, and comorbidity profiles.

RESULTS

Patients age 18-39 were more likely to suffer mechanical wound complications compared to patients age 65-79 (OR = 1.9, 95% CI [1.5, 2.4], p < .01) and to patients age 80 and over (OR = 2.9, 95% CI [2.2, 3.8], p < .01). Patients age 18-39 were also more likely to suffer postoperative infections compared to patients age 65-79 (OR = 1.4, 95% CI [1.1, 1.6], p < .01) and to patients age 80 and over (OR = 2.0, 95% CI [1.6, 2.6], p < .01). Other most significant predictors included male gender, fluid and electrolyte disorders, pulmonary circulation disorders, and weight loss, as well as patients with comorbidities. All statistically significant predictors with positive estimates for postoperative infections were also statistically significant predictors of mechanical wound complications.

CONCLUSIONS

Individual patient risk profile can be constructed using preoperative patient profiles for improving perioperative care coordination and patient care quality. Postoperative infections were associated with mechanical wound complications in patients undergoing elective open intestinal resection.

C4.4A gene ablation is compatible with normal epidermal development and causes modest overt phenotypes

C4.4A is a modular glycolipid-anchored Ly6/uPAR/α-neurotoxin multidomain protein that exhibits a prominent membrane-associated expression in stratified squamous epithelia. C4.4A is also expressed in various solid cancer lesions, where high expression levels often are correlated to poor prognosis. Circumstantial evidence suggests a role for C4.4A in cell adhesion, migration, and invasion, but a well-defined biological function is currently unknown. In the present study, we have generated and characterized the first C4.4A-deficient mouse line to gain insight into the functional significance of C4.4A in normal physiology and cancer progression. The unchallenged C4.4A-deficient mice were viable, fertile, born in a normal Mendelian distribution and, surprisingly, displayed normal development of squamous epithelia. The C4.4A-deficient mice were, nonetheless, significantly lighter than littermate controls predominantly due to differences in fat mass. Congenital C4.4A deficiency delayed migration of keratinocytes enclosing incisional skin wounds in male mice. In chemically induced bladder carcinomas, C4.4A deficiency attenuated the incidence of invasive lesions despite having no effect on total tumour burden. This new C4.4A-deficient mouse line provides a useful platform for future studies on functional aspects of C4.4A in tumour cell invasion in vivo.

Gender-Specific Differences in Surgical Site Infections: An Analysis of 438,050 Surgical Procedures from the German National Nosocomial Infections Surveillance System

Background

Surgical site infections (SSI) are among the most frequent healthcare-associated infections. They impose a substantial burden with increased morbidity and exceeding healthcare costs. Risk factors such as age, diabetes, and smoking status are commonly accounted for in the literature, but few studies address gender differences.

Methods

Data from the German Nosocomial Infections Surveillance System (Krankenhaus-Infektions-Surveillance-System (KISS)) from 2005 to 2010 were analysed for cardiac, vascular, visceral, and orthopaedic surgery, with a total of 438,050 surgical procedures and 8,639 SSI. Rates of SSI and isolated pathogens were analysed for gender.

Results

Women had a lower rate of SSI (SSI/100 procedures) in abdominal surgery than men (2.92 vs. 4.37; p < 0.001). No gender-specific differences were found in orthopaedic and vascular surgery, while women had a higher risk for SSI in cardiac surgery (5.50 vs. 3.02; p < 0.001). Isolated pathogens showed differences for sensitive Staphylococcus aureus and Pseudomonas aeruginosa, which were more frequent in women (both p = 0.007), while coagulase-negative staphylococci occurred more often in men (18.8 vs. 14.0%; p < 0.001).

Conclusion

Gender differences in SSI exist and are procedure-specific. The underlying mechanisms need to be further elucidated so that targeted measures for the prevention of SSI can be developed.

Recent advances on plasmin inhibitors for the treatment of fibrinolysis-related disorders

Growing evidence suggests that plasmin is involved in a number of physiological processes in addition to its key role in fibrin cleavage. Plasmin inhibition is critical in preventing adverse consequences arising from plasmin overactivity, e.g., blood loss that may follow cardiac surgery. Aprotinin was widely used as an antifibrinolytic drug before its discontinuation in 2008. Tranexamic acid and ε-aminocaproic acid, two small molecule plasmin inhibitors, are currently used in the clinic. Several molecules have been designed utilizing covalent, but reversible, chemistry relying on reactive cyclohexanones, nitrile warheads, and reactive aldehyde peptidomimetics. Other major classes of plasmin inhibitors include the cyclic peptidomimetics and polypeptides of the Kunitz and Kazal-type. Allosteric inhibitors of plasmin have also been designed including small molecule lysine analogs that bind to plasmin's kringle domain(s) and sulfated glycosaminoglycan mimetics that bind to plasmin's catalytic domain. Plasmin inhibitors have also been explored for resolving other disease states including cell metastasis, cell proliferation, angiogenesis, and embryo implantation. This review highlights functional and structural aspects of plasmin inhibitors with the goal of advancing their design.

The Impact of Lipoproteins on Wound Healing: Topical HDL Therapy Corrects Delayed Wound Healing in Apolipoprotein E Deficient Mice

Chronic non-healing wounds lead to considerable morbidity and mortality. Pleiotropic effects of high density lipoproteins (HDL) may beneficially affect wound healing. The objectives of this murine study were: (1) to investigate the hypothesis that hypercholesterolemia induces impaired wound healing and (2) to study the effect of topical HDL administration in a model of delayed wound healing. A circular full thickness wound was created on the back of each mouse. A silicone splint was used to counteract wound contraction. Coverage of the wound by granulation tissue and by epithelium was quantified every 2 days. Re-epithelialization from day 0 till day 10 was unexpectedly increased by 21.3% (p < 0.05) in C57BL/6 low density lipoprotein (LDLr) deficient mice with severe hypercholesterolemia (489 ± 14 mg/dL) compared to C57BL/6 mice and this effect was entirely abrogated following cholesterol lowering adenoviral LDLr gene transfer. In contrast, re-epithelialization in hypercholesterolemic (434 ± 16 mg/dL) C57BL/6 apolipoprotein (apo) E^−/− mice was 22.6% (p < 0.0001) lower than in C57BL/6 mice. Topical HDL gel administered every 2 days increased re-epithelialization by 25.7% (p < 0.01) in apo E^−/− mice. In conclusion, topical HDL application is an innovative therapeutic strategy that corrects impaired wound healing in apo E^−/− mice.