Antioxidant sol-gel improves cutaneous wound healing in streptozotocin-induced diabetic rats

New Amorphous Hydrogels with Proliferative Properties as Potential Tools in Wound Healing

The study and discovery of bioactive compounds and new formulations as potential tools for promoting the repair of dermoepidermal tissue in wound healing is of continuing interest. We have developed a new formulation of amorphous hydrogel based on sodium alginate (NaAlg); type I collagen, isolated by the authors from silver carp tails (COL); glycerol (Gli); Aloe vera gel powder (AV); and silver nanoparticles obtained by green synthesis with aqueous Cinnamomum verum extract (AgNPs@CIN) and vitamin C, respectively. The gel texture of the amorphous hydrogels was achieved by the addition of Aloe vera, demonstrated by a rheological analysis. The evaluations of the cytotoxicity and cell proliferation capacity of the experimental amorphous hydrogels were performed against human foreskin fibroblast Hs27 cells (CRL-1634-ATCC). The developed gel formulations did not show a cytotoxic effect. The hydrogel variant containing AgNPs@CIN in a concentration of 8 µg Ag/gel formulation and hydrogel variant with vitamin C had proliferative activity. In addition, the antibacterial activity of the hydrogels was evaluated against S. aureus ATCC 6538, Ps. aeruginosa ATCC 27853, and E. coli ATCC 25922. The results demonstrated that the gel variant based on AgNPs@CIN in a concentration of 95 µg Ag/gel formulation and the hydrogel based on vitamin C show antibacterial activity. Therefore, the developed hydrogels with AgNPs@CIN and vitamin C could be promising alternatives in wound healing.

Chronic Inflammation in Non-Healing Skin Wounds and Promising Natural Bioactive Compounds Treatment

Chronic inflammation is one of the hallmarks of chronic wounds and is tightly coupled to immune regulation. The dysregulation of the immune system leads to continuing inflammation and impaired wound healing and, subsequently, to chronic skin wounds. In this review, we discuss the role of the immune system, the involvement of inflammatory mediators and reactive oxygen species, the complication of bacterial infections in chronic wound healing, and the still-underexplored potential of natural bioactive compounds in wound treatment. We focus on natural compounds with antioxidant, anti-inflammatory, and antibacterial activities and their mechanisms of action, as well as on recent wound treatments and therapeutic advancements capitalizing on nanotechnology or new biomaterial platforms.

Diverse nanocomposites as a potential dressing for diabetic wound healing

Wound healing is a programmed process of continuous events which is impaired in the case of diabetic patients. This impaired process of healing in diabetics leads to amputation, longer hospitalisation, immobilisation, low self-esteem, and mortality in some patients. This problem has paved the way for several innovative strategies like the use of nanotechnology for the treatment of wounds in diabetic patients. The use of biomaterials, nanomaterials have advanced approaches in tissue engineering by designing multi-functional nanocomposite scaffolds. Stimuli-responsive scaffolds that interact with the wound microenvironment and controlled release of bioactive molecules have helped in overcoming barriers in healing. The use of different types of nanocomposite scaffolds for faster healing of diabetic wounds is constantly being studied. Nanocomposites have helped in addressing specific issues with respect to healing and improving angiogenesis. Method: A literature search was followed to retrieve the articles on strategies for wound healing in diabetes across several databases like PubMed, EMBASE, Scopus and Cochrane database. The search was performed in May 2022 by two researchers independently. They keywords used were "diabetic wounds, nanotechnology, nanocomposites, nanoparticles, chronic diabetic wounds, diabetic foot ulcer, hydrogel". Exclusion criteria included insulin resistance, burn wound, dressing material.

Alkaline Reduced Water Attenuates Oxidative Stress-Induced Mitochondrial Dysfunction and Innate Immune Response Triggered by Intestinal Epithelial Dysfunction

Redox imbalance in intestinal epithelial cells is critical in the early phases of intestinal injury. Dysfunction of the intestinal barrier can result in immunological imbalance and inflammation, thus leading to intestinal syndromes and associated illnesses. Several antioxidants have been discovered to be beneficial in resolving intestinal barrier dysfunction. Of these antioxidants, the effects of alkaline reduced water (ARW) in oxidative stress of intestinal epithelial cells and its immunokine modulation in vitro is unknown. In this study, we utilized ARW-enriched media to investigate its cytoprotective effect against H2O2-induced oxidative stress in DLD1 cells. We found that ARW rescued DLD1 from oxidative stress by diluting the influence of H2O2 on oxidative stress-activated MAPK signaling and mitochondrial dysfunction. Further, intestinal oxidative stress significantly affects immunokine profiles of Raw 264.7 cells (IL-6, IL-10, MCP, TNF-a, RANTES), which can be reversed by ARW. Collectively, ARW shields intestinal epithelial cells from oxidative stress, reducing the immunological mayhem caused by barrier failure.

Pseudomonas aeruginosa virulence proteins pseudolysin and protease IV impede cutaneous wound healing

The intricate biological process of cutaneous wound healing is achieved through precise and highly programmed events. Dermal fibroblasts and keratinocytes play a significant role in the process of reepithelialization during wound healing. Pathogenic bacteria such as Pseudomonas aeruginosa (P. aeruginosa) may delay the proliferative phase of wound repair by secreting their proteins leading to delayed or impaired wound healing. We have analyzed three virulent strains of P. aeruginosa isolated from the wound environment which also differed in their ability to produce biofilms. Mass spectrometric analysis of differentially expressed secreted proteins by three virulent strains of P. aeruginosa revealed peptides from pseudolysin and protease IV expressed from lasB and prpL genes. Pseudolysin and protease IV recombinant proteins were tested for their ability to modulate wound healing in several cell types of wound microenvironment in in vitro and in vivo models. Both pseudolysin and protease IV inhibited migration and survival of fibroblasts, keratinocytes, and endothelial cells. In three dimensional spheroid endothelial models and matrigel assays these proteins impeded sprouting and tube formation. In a mouse model of excision wound, pseudolysin and protease IV treatment showed reduced collagen content, inhibited neovascularization and epithelialization, and delayed wound contraction. Furthermore, pseudolysin and protease IV treatment resulted in a significant increase in plasma IL-6 levels when compared to vehicle control and control, suggesting the induction of a state of prolonged inflammation. Taken together, our data indicate pseudolysin and protease IV secreted from biofilm producing and antibiotic resistant P. aeruginosa in wound microenvironment produce both local and systemic effects that is detrimental to the maintenance of tissue homeostasis. Hence, these proteins may serve as potential therapeutic targets toward better clinical management of wounds.

Diabetes Upregulates Oxidative Stress and Downregulates Cardiac Protection to Exacerbate Myocardial Ischemia/Reperfusion Injury in Rats

Diabetes exacerbates myocardial ischemia/reperfusion (IR) injury by incompletely understood mechanisms. We explored whether diabetes diminished BAG3/Bcl-2/Nrf-2/HO-1-mediated cardioprotection and overproduced oxidative stress contributing to exaggerated IR injury. Streptozotocin-induced diabetes enhanced hyperglycemia, cardiac NADPH oxidase p22/p67 expression, malondialdehyde amount and leukocyte infiltration, altered the mesenteric expression of 4-HNE, CaSR, p-eNOS and BAG3 and impaired microvascular reactivity to the vasoconstrictor/vasodilator by a wire myography. In response to myocardial IR, diabetes further depressed BAG3/Bcl-2/Nrf-2/HO-1 expression, increased cleaved-caspase 3/poly(ADP-ribose) polymerase (PARP)/TUNEL-mediated apoptosis and exacerbated IR-induced left ventricular dysfunction characterized by further depressed microcirculation, heart rate, left ventricular systolic pressure and peak rate of pressure increase/decrease (±dp/dt) and elevated left ventricular end-diastolic pressure (LVEDP) and Evans blue-2,3,5-triphenyltetrazolium chloride-stained infarct size in diabetic hearts. Our results implicated diabetes exacerbated IR-induced myocardial dysfunction through downregulated BAG3/Bcl-2/Nrf-2/HO-1 expression, increased p22/p67/caspase 3/PARP/apoptosis-mediated oxidative injury and impaired microvascular reactivity.

The Effect of Myrtus communis Aqueous Extract-Containing Gel on Wound Healing in Streptozotocin-Induced Diabetic Rats

BACKGROUND

The medicinal plant Myrtus communis L. (Myrtle) has properties, including anti-inflammatory and wound healing in Persian Medicine.

OBJECTIVE

The objective of this study was to explore the wound healing potential of the local application of a gel containing aqueous extract of the plant berry in streptozotocin (STZ)-induced diabetic rats.

METHODS

Seven days after diabetes establishment, full-thickness excision skin wounds were made in normal and diabetic rats where treated groups received topical application of a gel containing 6% aqueous extract of myrtle berries for 3 weeks. The rate of wound healing and the level of epidermal and dermal maturation in the wound tissue were determined.

RESULTS

The results showed that after 3 and 7 days of wound injury, the gel significantly improved wound healing by accelerating epidermal and dermal maturation in diabetic rats with no significant effect in the control group. However, the wounds of all groups almost completely healed after 3 weeks.

CONCLUSION

These results demonstrate that aqueous extract of myrtle possesses a definite wound healing potential in diabetic conditions. The present findings may suggest the use of topical myrtle berries aqueous extract gel 6% to treat and manage intractable diabetic wounds.

Rutin-Loaded Poloxamer 407-Based Hydrogels for In Situ Administration: Stability Profiles and Rheological Properties

Rutin is a flavone glycoside contained in many plants, and exhibits antioxidant, anti-inflammatory, anticancer, and wound-healing properties. The main disadvantage related to the use of this molecule for pharmaceutical application is its poor bioavailability, due to its low solubility in aqueous media. Poloxamer 407-hydrogels show interesting thermo-sensitive properties that make them attractive candidates as pharmaceutical formulations. The hydrophobic domains in the chemical structure of the copolymer, a polymer made up of two or more monomer species, are useful for retaining poorly water-soluble compounds. In this investigation various poloxamer 407-based hydrogels containing rutin were developed and characterized as a function of the drug concentration. In detail, the Turbiscan stability index, the micro- and dynamic rheological profiles and in vitro drug release were investigated and discussed. Rutin (either as a free powder or solubilized in ethanol) did not modify the stability or the rheological properties of these poloxamer 407-based hydrogels. The drug leakage was constant and prolonged for up to 72 h. The formulations described are expected to represent suitable systems for the in situ application of the bioactive as a consequence of their peculiar versatility.

Bioactive antibacterial silica-based nanocomposites hydrogel scaffolds with high angiogenesis for promoting diabetic wound healing and skin repair

Diabetic wound repair and skin regeneration remains a worldwide challenge due to the impaired functionality of re-vascularization. Methods: This study reports a bioactive self-healing antibacterial injectable dual-network silica-based nanocomposite hydrogel scaffolds that can significantly enhance the diabetic wound healing/skin tissue formation through promoting early angiogenesis without adding any bioactive factors. The nanocomposite scaffold comprises a main network of polyethylene glycol diacrylate (PEGDA) forming scaffolds, with an auxiliary dynamic network formed between bioactive glass nanoparticles containing copper (BGNC) and sodium alginate (ALG) (PABC scaffolds). Results: PABC scaffolds exhibit the biomimetic elastomeric mechanical properties, excellent injectabilities, self-healing behavior, as well as the robust broad-spectrum antibacterial activity. Importantly, PABC hydrogel significantly promoted the viability, proliferation and angiogenic ability of endothelial progenitor cells (EPCs) in vitro. In vivo, PABC hydrogel could efficiently restore blood vessels networks through enhancing HIF-1α/VEGF expression and collagen matrix deposition in the full-thickness diabetic wound, and significantly accelerate wound healing and skin tissue regeneration. Conclusion: The prominent multifunctional properties and angiogenic capacity of PABC hydrogel scaffolds enable their promising applications in angiogenesis-related regenerative medicine.

Preparation and Comparison of Effects of Different Herbal Oil Ointments as Wound-Healing Agents

Wound healing is a complex process and some agents have been reported to accelerate it. The aim of this study was to evaluate the healing effect of Eucerin-based ointments of lemon, sesame and olive oils on infected full-thickness wounds in rats. Wounds were created on the dorsal surface of Male Albino Wistar rats (n = 12). Wounds were treated with an Eucerin-based ointment containing either of lemon, sesame or olive oils (33% w/w) twice a day for 14 days. Histopathology results showed that contraction of wounds treated with lemon and sesame oils was higher than in the olive oil and control groups on days 10 and 14. In the lemon- and sesame-oil treated groups, on day 14, 50% of rat lesions were completely healed. Total number of inflammatory cells in lemon oil treatment group was significantly smaller than that of others on day 14 (p < 0.001). Also, thickness of the epidermal layer and rejuvenation of the hair follicles and other skin appendages was normal in lemon and sesame oil treated groups. The lemon and sesame oil ointments accelerated the healing process of wounds in macroscopic, morphological and morphmetrical analyses. Therefore, lemon and sesame oil ointments could be considered as alternative dressings for infected full-thickness wounds because of improved wound healing characteristics.

lncRNA MALAT1 Accelerates Wound Healing of Diabetic Mice Transfused with Modified Autologous Blood via the HIF-1α Signaling Pathway

Impaired wound healing is a debilitating complication of diabetes. The long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been recognized to be differentially expressed in various diseases. However, its underlying mechanism in diabetes has not been fully understood. Notably, we aim to examine the expression of MALAT1 in diabetic mice and its role in wound healing involving the hypoxia-inducible factor-1α (HIF-1α) signaling pathway with a modified autologous blood preservative solution reported. A mouse model of diabetes was established. MALAT1 was identified to promote the activation of the HIF-1α signaling pathway and to be enriched in autologous blood through modified preservation, which might facilitate the improvement of physiological function of blood cells. Through gain- or loss-of-function approaches, viability of fibroblasts cultured in high glucose, wound healing of mice, and collagen expression in wound areas were enhanced by MALAT1 and HIF-1α. Taken together, the present study demonstrated that the physiological status of mouse blood was effectively improved by modified autologous blood preservation, which exhibited upregulated MALAT1, thereby accelerating the fibroblast activation and wound healing in diabetic mice via the activation of the HIF-1α signaling pathway. The upregulation of MALAT1 activating the HIF-1α signaling pathway provides a novel insight into drug targets against diabetes.

Exogenous hydrogen sulphide supplement accelerates skin wound healing via oxidative stress inhibition and vascular endothelial growth factor enhancement

Hydrogen sulphide (H₂ S) is an important gasotransmitter with several physiological functions. However, the roles and the detailed mechanisms of H₂ S on skin wound healing are not known well. In the present study, 129S1/SvImJ mice were intraperitoneally injected with NaHS (50 μmol/kg/d) for 2 weeks. Then, a round wound of 6 mm diameter with depth into the dermis was made. The skin wound area, blood perfusion, superoxide production, malondialdehyde (MDA) levels, total antioxidant capacity (T-AOC), expression of vascular endothelial growth factor (VEGF), dynamin-related protein 1 (DRP1) and optic atrophy 1 (OPA1) were measured. After NaHS (50 μmol/L) pre-administration for 4 hours, cell migration rate, DRP1, OPA1 and α-smooth muscle actin (α-SMA) expression, superoxide production and mitochondrial membrane potential in primary skin fibroblasts were measured. Tube formation in human umbilical vein endothelial cells (HUVECs) and cell migration in human keratinocytes were also measured. The results showed that NaHS pretreatment significantly accelerated wound healing and improved blood flow in the wound after operation. NaHS increased VEGF expression in the wound and promoted tube formation in HUVECs. Meanwhile, NaHS attenuated reactive oxygen species (ROS) production, suppressed MDA level but restored T-AOC in the wound. NaHS also promoted skin fibroblasts migration and α-SMA expression after scratch. Moreover, NaHS alleviated ROS, increased mitochondrial membrane potential, decreased DRP1 but enhanced OPA1 expression in skin fibroblasts after scratch. NaHS also accelerated human keratinocytes migration after scratch. Taken together, exogenous H₂ S supplementary accelerated the skin wound healing, which might be related to oxidative stress inhibition and VEGF enhancement.

Antioxidant-antibacterial containing bi-layer scaffolds as potential candidates for management of oxidative stress and infections in wound healing

Tissue engineering techniques are continuously evolving towards providing better microenvironment along with therapeutic potential to address the skin tissue defects. Factors such as microbial infections, presence of excessive free radicals and depletion in antioxidant based scavenging systems pose serious challenges by prolonging inflammation and delaying the repair process. Incorporation of bioactive molecules in polymer based biomimetic scaffolds may present new vistas for handling chronic wounds. In this study, chitosan/collagen scaffolds incorporating 0.5, 1 and 2% (w/w) silymarin (CS-CO-SM) were synthesized and studied for their biocompatibility, in vitro release kinetics and anti-oxidant activity. The release kinetics of silymarin from the CS-CO-SM scaffold showed an initial burst followed by sustained release. The scaffolds were biocompatible and supported the recovery of COS-7 cells from UV induced oxidative stress. Further the CS-CO-SM₍₂₎ scaffolds were used to fabricate a bi-layer scaffold by layer upon layer arrangement with CS-Ag3 (3% Ag, w/w). The Ag was incorporated to impart antimicrobial property to the scaffold. The in vivo studies on bi-layer scaffolds were carried out in Wistar rat models at 3, 7 and 10 days post injury and the skin excisions were studied for wound contraction, histology (H&E staining), and lipid peroxidation. The bi-layer scaffold accelerated the process of wound healing with no inflammatory cells, proliferation of fibroblast, neovascularization and collagen deposition. By day 10 post transplantation of the scaffold, the skin had a structure similar to normal skin with complete re-epithelization. This bi-layer scaffold with antioxidant and antimicrobial properties promotes wound healing and is proposed as a potential tissue engineering material for managing chronic wounds.

Potentiation effect on accelerating diabetic wound healing using 2-N,6-O-sulfated chitosan-doped PLGA scaffold

Accelerating the wound healing of diabetes-impaired cutaneous tissue is still a challenge due to the aberrant cellular behavior, poor angiogenesis, and pathological micro-environment. Activation with growth factors and modulation of the redox micro-environment of the diabetic wound are considered to be effective strategies. Herein, we have described a highly sulfated heparin-like polysaccharide 2-N, 6-O-sulfated chitosan (26SCS)-doped poly(lactic-co-glycolic acid) scaffold (S-PLGA), which can achieve controlled and sustained release of heparin-binding epidermal growth factor (HB-EGF) owing to its affinity for heparin-binding growth factors. Interestingly, the antioxidant effect of 26SCS was confirmed and it was shown to have a strong scavenging activity towards superoxide radicals, a moderate scavenging activity towards hydroxyl radicals and a lower scavenging activity towards hydrogen peroxide. It also exhibited stronger protective effects in a human keratinocyte cell line (Ha-cat) against H₂O₂-induced oxidative damage. The Ha-cat cells cultured in the presence of the S-PLGA scaffold were significantly protected against oxidative stress during proliferation. In a full thickness excisional wound model of a diabetic rat, the wound treated with the HB-EGF-loaded S-PLGA scaffold was basically healed after 28 days. Conversely, the wounds in the other diabetic groups were not closed. The migration effect of the keratinocytes was enhanced by the 26SCS-induced sustainable release of HB-EGF and the scavenging of ROS which led to rapid re-epithelialization. Furthermore, histopathological evaluation demonstrated the positive effects on wound contraction, epithelial regeneration, and collagen deposition when treated with the HB-EGF loaded S-PLGA scaffold. These findings highlight that 26SCS may serve as a promising coagent for both controlled release of growth factors and alleviation of excessive ROS production, thus leading to increased regeneration of the diabetic wounds.

WOUND HEALING ACTIVITY OF SHEEP’S BLADDER EXTRACELLULAR MATRIX IN DIABETIC RATS

Diabetic ulcers (DUs) are a chronic, non-healing diabetes complication that leads to high hospital expenses and, in extreme cases, to amputation. Peripheral vascular diseases, diabetic neuropathy, abnormal cellular and cytokine activity are among the major factors that hinder diabetic wound healing. DUs represent an important challenge in the development of new and efficient wound dressings. The extracellular matrix (ECM) has been effectively used as a scaffold for constructive remodeling of multiple tissues in animal and human. Sheep’s urinary bladder matrix was evaluated for its wound healing activity in streptozotocin-induced diabetic rats using excision model. In this experiment, 48 male Sprague dawley rats weighing 220–250[Formula: see text]g were divided into four equal groups of control, vaseline, diabetics + (10[Formula: see text]mg/wound) and [Formula: see text] (50[Formula: see text]mg/wound). Diabetes was induced by intraperitoneal injection of streptozotocin (45[Formula: see text]mg/kg B.W) solved in 0.05[Formula: see text]M citrate buffer. Seven days after confirming diabetes statue, skin wounds were created on the back of each rat. Rate of wound healing and histological assay using hematoxylin and Eosin staining (H&E) were used for evaluation of the wound healing in different groups. ECM treated animals exhibited significant improvement in both wound area and rate of wound healing when compared to controls ([Formula: see text]). The ECM treated wounds were found to epithelize faster as compared to controls. The sheep’s ECM promotes significant wound healing in male diabetic rats and further studies on this activity in animal models and humans are suggested.

Preventive effects of royal jelly against anaphylactic response in a murine model of cow's milk allergy

CONTEXT

Royal jelly (RJ) has long been used to promote human health.

OBJECTIVE

The current study investigated the preventive effects of RJ against the development of a systemic and intestinal immune response in mice allergic to cow's milk proteins.

MATERIALS AND METHODS

Balb/c mice treated orally for seven days with RJ at doses of 0.5, 1 and 1.5 g/kg were sensitized intraperitoneally with β-lactoglobulin (β-Lg). Serum IgG and IgE anti-β-Lg were determined by an enzyme-linked immunosorbent assay (ELISA). Plasma histamine levels, symptom scores and body temperature were determined after in vivo challenge to β-Lg. Jejunums were used for assessment of local anaphylactic responses by an ex vivo study in Ussing chambers and morphologic changes by histological analysis.

RESULTS

RJ significantly decreased serum IgG (31.15-43.78%) and IgE (64.28-66.6%) anti-β-Lg and effectively reduced plasma histamine level (66.62-67.36%) (p < 0.001) at all the doses tested. Additionally, no clinical symptoms or body temperature drops were observed in RJ-pretreated mice. Interestingly, RJ significantly reduced (p < 0.001) intestinal dysfunction by abolishing the secretory response (70.73-72.23%) induced by sensitization and prevented length aberrations of jejunal villi by 44.32-59.01% (p < 0.001).

DISCUSSION AND CONCLUSIONS

We speculate that using RJ may help prevent systemic and anaphylactic response in allergic mice. These effects may be related to its inhibitory effects on the degranulation of mast cells.

Redox Signaling in Diabetic Wound Healing Regulates Extracellular Matrix Deposition

SIGNIFICANCE

Impaired wound healing is a major complication of diabetes, and can lead to development of chronic foot ulcers in a significant number of patients. Despite the danger posed by poor healing, very few specific therapies exist, leaving patients at risk of hospitalization, amputation, and further decline in overall health. Recent Advances: Redox signaling is a key regulator of wound healing, especially through its influence on the extracellular matrix (ECM). Normal redox signaling is disrupted in diabetes leading to several pathological mechanisms that alter the balance between reactive oxygen species (ROS) generation and scavenging. Importantly, pathological oxidative stress can alter ECM structure and function.

CRITICAL ISSUES

There is limited understanding of the specific role of altered redox signaling in the diabetic wound, although there is evidence that ROS are involved in the underlying pathology.

FUTURE DIRECTIONS

Preclinical studies of antioxidant-based therapies for diabetic wound healing have yielded promising results. Redox-based therapeutics constitute a novel approach for the treatment of wounds in diabetes patients that deserve further investigation. Antioxid. Redox Signal. 27, 823-838.

Boron promotes streptozotocin-induced diabetic wound healing: roles in cell proliferation and migration, growth factor expression, and inflammation

Acute wounds do not generally require professional treatment modalities and heal in a predictable fashion, but chronic wounds are mainly accompanied with infection and prolonged inflammation, leading to healing impairments and continuous tissue degradation. Although a vast amount of products have been introduced in the market, claiming to provide a better optimization of local and systemic conditions of patients, they do not meet the expectations due to being expensive and not easily accessible, requiring wound care facilities, having patient-specific response, low efficiency, and severe side-effects. In this sense, developing new, safe, self-applicable, effective, and cheap wound care products with broad-range antimicrobial activity is still an attractive area of international research. In the present work, boron derivatives [boric acid and sodium pentaborate pentahydrate (NaB)] were evaluated for their antimicrobial activity, proliferation, migratory, angiogenesis, gene, and growth factor expression promoting effects on dermal cells in vitro. In addition, boron-containing hydrogel formulation was examined for its wound healing promoting potential using full-thickness wound model in streptozotocin-induced diabetic rats. The results revealed that while both boron compounds significantly increased proliferation, migration, vital growth factor, and gene expression levels of dermal cells along with displaying remarkable antimicrobial effects against bacteria, yeast, and fungi, NaB displayed greater antimicrobial properties as well as gene and growth factor expression inductive effects. Animal studies proved that NaB-containing gel formulation enhanced wound healing rate of diabetic animals and histopathological scores. Overall data suggest a potential promising therapeutic option for the management of chronic wounds but further studies are highly warranted to determine signaling pathways and target metabolisms in which boron is involved to elucidate the limitations and extend its use in clinics.

Nesfatin-1 improves oxidative skin injury in normoglycemic or hyperglycemic rats

Hyperglycemia is one of the major causes of suppressed angiogenesis and impaired wound healing leading to chronic wounds. Nesfatin-1 a novel peptide was reported to have antioxidant and anti-apoptotic properties. This study is aimed to investigate the potential healing-promoting effects of nesfatin-1 in non-diabetic or diabetic rats with surgical wounds. In male Sprague-Dawley rats, hyperglycemia was induced by intraperitoneal (ip) injection of streptozotocin (55 mg/kg). Under anesthesia, dorsum skin tissues of normoglycemic (n=16) and hyperglycemic rats were excised (2 × 2 cm, full-thickness), while control rats (n=16) had neither hyperglycemia nor wounds. Half of the rats in each group were treated ip with saline, while the others were treated with nesfatin-1 (2 μg/kg/day) for 3 days until they were decapitated. Plasma interleukin-1-beta (IL-1β), transforming growth factor-beta (TGF-β-1), IL-6 levels, and dermal tissue malondialdehyde (MDA), glutathione (GSH) levels, myeloperoxidase (MPO) and caspase-3 activity were measured. For histological examination, paraffin sections were stained with hematoxylin-eosin or Masson's trichrome and immunohistochemistry for vascular endothelial growth factor (VEGF) was applied. ANOVA and Student's t-tests were used for statistical analysis. Compared to control rats, skin MPO activity, MDA and caspase-3 levels were increased similarly in saline-treated normo- and hyperglycemic rats. Nesfatin-1 depressed MDA, caspase-3, MPO activity and IL-1β with concomitant elevations in dermal GSH and plasma TGF-β-1 levels. Histopathological examination revealed regeneration of epidermis, regular arrangement of collagen fibers in the dermis and a decrease in VEGF immunoreactivity in the epidermal keratinocytes of nesfatin-1-treated groups. Nesfatin-1 improved surgical wound healing in both normo- and hyperglycemic rats via the suppression of neutrophil recruitment, apoptosis and VEGF activation.

Combined effects of low-level laser therapy and human bone marrow mesenchymal stem cell conditioned medium on viability of human dermal fibroblasts cultured in a high-glucose medium

Low-level laser therapy (LLLT) exhibited biostimulatory effects on fibroblasts viability. Secretomes can be administered to culture mediums by using bone marrow mesenchymal stem cells conditioned medium (BM-MSCs CM). This study investigated the combined effects of LLLT and human bone marrow mesenchymal stem cell conditioned medium (hBM-MSCs CM) on the cellular viability of human dermal fibroblasts (HDFs), which was cultured in a high-glucose (HG) concentration medium. The HDFs were cultured either in a concentration of physiologic (normal) glucose (NG; 5.5 mM/l) or in HG media (15 mM/l) for 4 days. LLLT was performed with a continuous-wave helium-neon laser (632.8 nm, power density of 0.00185 W/cm(2) and energy densities of 0.5, 1, and 2 J/cm(2)). About 10% of hBM-MSCs CM was added to the HG HDF culture medium. The viability of HDFs was evaluated using dimethylthiazol-diphenyltetrazolium bromide (MTT) assay. A significantly higher cell viability was observed when laser of either 0.5 or 1 J/cm(2) was used to treat HG HDFs, compared to the control groups. The cellular viability of HG-treated HDFs was significantly lower compared to the LLLT + HG HDFs, hBM-MSCs CM-treated HG HDFs, and LLLT + hBM-MSCs CM-treated HG HDFs. In conclusion, hBM-MSCs CM or LLLT alone increased the survival of HG HDFs cells. However, the combination of hBM-MSCs CM and LLLT improved these results in comparison to the conditioned medium.

Sirtuin-6 deficiency exacerbates diabetes-induced impairment of wound healing

Delayed wound healing is one of the major complications in diabetes and is characterized by chronic proinflammatory response, and abnormalities in angiogenesis and collagen deposition. Sirtuin family proteins regulate numerous pathophysiological processes, including those involved in promotion of longevity, DNA repair, glycolysis and inflammation. However, the role of sirtuin 6 (SIRT6), a NAD+-dependent nuclear deacetylase, in wound healing specifically under diabetic condition remains unclear. To analyse the role of SIRT6 in cutaneous wound healing, paired 6-mm stented wound was created in diabetic db/db mice and injected siRNA against SIRT6 in the wound margins (transfection agent alone and nonsense siRNA served as controls). Wound time to closure was assessed by digital planimetry, and wounds were harvested for histology, immunohistochemistry and Western blotting. SIRT6-siRNA-treated diabetic wound showed impaired healing, which was associated with reduced capillary density (CD31-staining vessels) when compared to control treatment. Interestingly, SIRT6 deficiency decreased vascular endothelial growth factor expression and proliferation markers in the wounds. Furthermore, SIRT6 ablation in diabetic wound promotes nuclear factor-κB (NF-κB) activation resulting in increased expression of proinflammatory markers (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, tumor necrosis factor-α and interleukin-1β) and increased oxidative stress. Collectively, our findings demonstrate that loss of SIRT6 in cutaneous wound aggravates proinflammatory response by increasing NF-κB activation, oxidative stress and decrease in angiogenesis in the diabetic mice. Based on these findings, we speculate that the activation of SIRT6 signalling might be a potential therapeutic approach for promoting wound healing in diabetics.

Effects of paroxetine on cutaneous wound healing in healthy and diabetic rats

OBJECTIVE

The aim of this study was to evaluate the histologic effects of acute paroxetine administration on wound healing in healthy and streptozotocin-induced diabetic rats.

DESIGN

This study has a randomized controlled experimental design.

SETTING

Healthy (n = 32) and diabetic (n = 32) rats were further divided into 2 groups of saline or paroxetine administration.

PARTICIPANTS

Sixty-four male Sprague-Dawley rats were used in this study.

INTERVENTIONS

Paroxetine was injected intraperitoneally every day. Full-thickness excision wounds were created with a 4-mm dermal punch on the back of all rats. The healing wound area was removed with a 6-mm dermal punch at postwounding days 1, 3, 7, and 14.

MAIN OUTCOME MEASURES

Polymorphonuclear leukocyte, mononuclear inflammatory cell, fibroblast, and blood vessel counts and epithelialization were evaluated under light microscope.

MAIN RESULTS

There was no statistically significant difference observed in the polymorphonuclear leukocyte, mononuclear inflammatory cell, and blood vessel counts in the healthy and diabetic rats with and without paroxetine administration. The number of fibroblasts was significantly higher at postwounding day 14 of the paroxetine-administered healthy rats compared with the saline-administered healthy rats (P = .04). However, the number of fibroblasts did not show any difference by paroxetine administration in the diabetic rats. There was no statistically significant difference in epithelialization regarding all the postwounding days, but complete epithelialization was observed in all rats on postwounding day 14 in the healthy and paroxetine-administered group.

CONCLUSION

Short-term paroxetine administration may enhance cutaneous wound healing by increasing the number of fibroblasts and causing better epithelialization over time in healthy rats but not in diabetic rats.

The effect of topical application of royal jelly on chemoradiotherapy-induced mucositis in head and neck cancer: a preliminary study

Purpose. One of the common side effects experienced by head and neck cancer patients on chemoradiotherapy is mucositis. Severe mucositis may be controllable by limiting cancer therapy, but it has resulted in decreasing the completion rate of chemoradiotherapy. The efficacy of royal jelly (RJ) as prophylaxis against chemoradiotherapy-induced mucositis was evaluated through clinical scoring of oral and pharyngeal mucositis. Methods. In this randomized, single-blind (physician-blind), clinical trial, 13 patients with head and neck cancer requiring chemoradiation were randomly assigned to two groups. Seven patients assigned to the study group received RJ, and 6 patients were assigned to the control group. RJ group patients took RJ three times per day during treatment. The patients in both groups were evaluated twice a week for the development of mucositis using Common Terminology Criteria for Adverse Events version 3.0. Results. A significant reduction in mucositis was seen among RJ-treated patients compared with controls (P < 0.001). Conclusion. This study demonstrated that prophylactic use of RJ was effective in reducing mucositis induced by chemoradiotherapy in head and neck cancer patients. However, further studies are needed because of the small sample size and the absence of double blinding.

The effects of caffeine on wound healing

The purine alkaloid caffeine is a major component of many beverages such as coffee and tea. Caffeine and its metabolites theobromine and xanthine have been shown to have antioxidant properties. Caffeine can also act as adenosine-receptor antagonist. Although it has been shown that adenosine and antioxidants promote wound healing, the effect of caffeine on wound healing is currently unknown. To investigate the effects of caffeine on processes involved in epithelialisation, we used primary human keratinocytes, HaCaT cell line and ex vivo model of human skin. First, we tested the effects of caffeine on cell proliferation, differentiation, adhesion and migration, processes essential for normal wound epithelialisation and closure. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) proliferation assay to test the effects of seven different caffeine doses ranging from 0·1 to 5 mM. We found that caffeine restricted cell proliferation of keratinocytes in a dose-dependent manner. Furthermore, scratch wound assays performed on keratinocyte monolayers indicated dose-dependent delays in cell migration. Interestingly, adhesion and differentiation remained unaffected in monolayer cultures treated with various doses of caffeine. Using a human ex vivo wound healing model, we tested topical application of caffeine and found that it impedes epithelialisation, confirming in vitro data. We conclude that caffeine, which is known to have antioxidant properties, impedes keratinocyte proliferation and migration, suggesting that it may have an inhibitory effect on wound healing and epithelialisation. Therefore, our findings are more in support of a role for caffeine as adenosine-receptor antagonist that would negate the effect of adenosine in promoting wound healing.

Sphingosine kinase 1 improves cutaneous wound healing in diabetic rats

BACKGROUND

Diabetes is one of the most prevalent human metabolic diseases. Wound healing in diabetes is frequently impaired and treatment remains challenging. Sphingolipid metabolites play important roles in the regulation of glucose metabolism. SPK1 is the key enzyme in the sphingolipid metabolic pathway. S1P/SPK plays a pivotal role in the signalling pathways of diverse cellular processes including proliferation, differentiation, migration, apoptosis in diverse cell types.

METHODS

To investigate the role of sphingosine kinase 1 (SPK1) in skin injury, plasmids containing the SPK1 gene (pcDNA3-FLAG-SPK1) were applied to cutaneous wounds on a streptozotocin-induced diabetic rat model over a 21-day period. The wound area and rate of wound healing were determined. The histopathological features of the healed wounds were also observed, and SPK1 expression in the skin was detected by immunohistochemistry.

RESULTS

There was a significant decrease in wound area in diabetic rats treated with 125 and 60μg/wound pcDNA3-FLAG-SPK1 (P<0.001-0.01). The mean sizes of the wounds were 0.67±0.15cm(2), 0.83±0.18cm(2), and 1.09±0.23cm(2) in both treated and diabetic control group at the 7th day post-treatment respectively. In addition, wound healing in diabetic rats of test group was accelerated. At the 7th day, the mean rates of healing were 73.2±5.7% and 66±7.3% in test group of 125 and 60μg/wound respectively, and 55.4±9.9% in diabetic control group (P<0.001-0.01). Histology revealed that tissue sections from the treated diabetic rats contained more granulation tissue and capillaries than that of the control rats. There was high SPK1 expression in the skin of the treated diabetic rats.

CONCLUSIONS

SPK1 gene therapy may represent a novel approach to cutaneous wound healing.

Synergistic effect of bone marrow-derived mesenchymal stem cells and platelet-rich plasma in streptozotocin-induced diabetic rats

Background

Diabetic wounds are a major clinical challenge, because minor skin wounds can lead to chronic, unhealed ulcers and ultimately result in infection, gangrene, or even amputation. Studies on bone marrow derived mesenchymal stem cells (BMSCs) and a series of growth factors have revealed their many benefits for wound healing and regeneration. Platelet-rich plasma (PRP) may improve the environment for BMSC development and differentiation. However, whether combined use of BMSCs and PRP may be more effective for accelerating diabetic ulcer healing remains unclear.

Objective

We investigated the efficacy of BMSCs and PRP for the repair of refractory wound healing in a diabetic rat model.

Methods

Forty-eight rats with diabetes mellitus induced by streptozotocin were divided into four groups: treatment with BMSCs plus PRP, BMSCs alone, PRP alone, phosphate buffered saline. The rate of wound closure was quantified. A histopathological study was conducted regarding wound depth and the skin edge at 7, 14, and 28 days after surgery.

Results

Wound healing rates were significantly higher in the BMSC plus PRP group than in the other groups. The immunohistochemistry results showed that the expression of platelet/endothelial cell adhesion molecule 1, proliferating cell nuclear antigen, and transforming growth factor-β1 increased significantly in the BMSC plus PRP group compared to the other treatment groups. On day 7, CD68 expression increased significantly in the wounds of the BMSC plus PRP group, but decreased markedly at day 14 compared to the controls.

Conclusion

The combination of BMSCs and PRP aids diabetic wound repair and regeneration.

Impact of the controlled release of a connexin 43 peptide on corneal wound closure in an STZ model of type I diabetes

The alpha-carboxy terminus 1 (αCT1) peptide is a synthetically produced mimetic modified from the DDLEI C-terminus sequence of connexin 43 (Cx43). Previous research using various wound healing models have found promising therapeutic effects when applying the drug, resulting in increased wound healing rates and reduced scarring. Previous data suggested a rapid metabolism rate in vitro, creating an interest in long term release. Using a streptozotocin (STZ) type I diabetic rat model with a surgically induced corneal injury, we delivered αCT1 both directly, in a pluronic gel solution, and in a sustained system, using polymeric alginate-poly-l-ornithine (A-PLO) microcapsules (MC). Fluorescent staining of wound area over a 5 day period indicated a significant increase in wound closure rates for both αCT1 and αCT1 MC treated groups, withαCT1 MC groups showing the most rapid wound closure overall. Analysis of inflammatory reaction to the treatment groups indicated significantly lower levels of both Interferon Inducible T-Cell Alpha Chemoattractant (ITAC) and Tumor Necrosis Factor Alpha (TNFα) markers using confocal quantification and ELISA assays. Additional analysis examining genes selected from the EMT pathway using RT-PCR and Western blotting suggested αCT1 modification of Transforming Growth Factor Beta 2 (TGFβ2), Keratin 8 (Krt8), Estrogen Receptor 1 (Esr1), and Glucose Transporter 4 (Glut4) over a 14 day period. Combined, this data indicated a possible suppression of the inflammatory response by αCT1, leading to increased wound healing rates.

Deficient cytokine expression and neutrophil oxidative burst contribute to impaired cutaneous wound healing in diabetic, biofilm-containing chronic wounds

Diabetic patients exhibit dysregulated inflammatory and immune responses that predispose them to chronic wound infections and the threat of limb loss. The molecular underpinnings responsible for this have not been well elucidated, particularly in the setting of wound biofilms. This study evaluates host responses in biofilm-impaired wounds using the TallyHo mouse, a clinically relevant polygenic model of type 2 diabetes. No differences in cytokine or Toll-like receptor (TLR) expression were noted in unwounded skin or noninoculated wounds of diabetic and wild-type mice. However, diabetic biofilm-containing wounds had significantly less TLR 2, TLR 4, interleukin-1β, and tumor necrosis factor-α expression than wild-type wounds with biofilm (all p < 0.001). Both groups had similar bacterial burden and neutrophil infiltration after development of biofilms at 3 days postwounding, but diabetic wounds had significantly less neutrophil oxidative burst activity. This translated into a log-fold greater bacterial burden and significant delay of wound epithelization for biofilm-impaired diabetic wounds at 10 days postwounding. These results suggest that impaired recognition of bacterial infection via the TLR pathway leading to inadequate cytokine stimulation of antimicrobial host responses may represent a potential mechanism underlying diabetic susceptibility to wound infection and ulceration.