Healing Of Full-thickness Excisional Wounds Research Articles

The effect ofcold atmospheric plasma (NO) alone and incombination with NPH insulin onthe full-thickness excisional wound healing inadiabetic rat model.

This study was planned toinvestigate analternative treatment modality indiabetic wound healing. Inthis experimental study, the efficacy ofboth cold atmospheric plasma/nitric oxide (NO) and NPH insulin ointment, recently known tohave beneficial effects onwound healing, was investigated indiabetic wound healing. Twenty-four (24) diabetic rats were divided into four groups DC, DI, DNO and DINO (diabetic control, diabetic insulin, diabetic nitric oxide, diabetic insulin+ nitric oxide groups). Notreatment was applied tothe DC group, NPH insulin was applied tothe DI group, CAP/NO was applied tothe DNO group, and CAP/NO+ NPH insulin was applied tothe DINO group once daily for 14days. The wound area reduction and the wound contraction rate were calculated onthe basis ofthe tissue sections taken, and histopathological and genetic analyses were carried out. Compared tothe control group, exogenous NO gas was found tobe apotent antibacterial agent inthe diabetic wound healing, causing areduction inthe wound area (P=0.034), anincreased contraction rate (P=0.021), epithelialisation (P=0.02), collagen organisation (P=0.006) and areduction inthe number ofinflammatory cells (P=0.002). Asignificant increase inthe expression ofIL-8 mRNA was observed (P=0.026). Itwas concluded that NPH insulin alone contributes towound healing, but itis not necessary touse ittogether with exogenous NO gas.

Polyphenol-driven facile assembly of a nanosized acid fibroblast growth factor-containing coacervate accelerates the healing of diabetic wounds.

Diabetic wounds are challenging to heal due to complex pathogenic abnormalities. Routine treatment with acid fibroblast growth factor (aFGF) is widely used for diabetic wounds but hardly offers a satisfying outcome due to its instability. Despite the emergence of various nanoparticle-based protein delivery approaches, it remains challenging to engineer a versatile delivery system capable of enhancing protein stability without the need for complex preparation. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and Epigallocatechin-3-gallate (EGCG) was constructed and applied in the healing of diabetic wounds. First, the binding patterns of EGCG and aFGF were predicted by molecular docking analysis. Then, the characterizations demonstrated that AE-NPs displayed higher stability in hostile conditions than free aFGF by enhancing the binding activity of aFGF to cell surface receptors. Meanwhile, the AE-NPs also had a powerful ability to scavenge reactive oxygen species (ROS) and promote angiogenesis, which significantly accelerated full-thickness excisional wound healing in diabetic mice. Besides, the AE-NPs suppressed the early scar formation by improving collagen remodeling and the mechanism was associated with the TGF-β/Smad signaling pathway. Conclusively, AE-NPs might be a potential and facile strategy for stabilizing protein drugs and achieving the scar-free healing of diabetic wounds. STATEMENT OF SIGNIFICANCE: Diabetic chronic wound is among the serious complications of diabetes that eventually cause the amputation of limbs. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and EGCG was constructed. The EGCG not only acted as a carrier but also possessed a therapeutic effect of ROS scavenging. The AE-NPs enhanced the binding activity of aFGF to cell surface receptors on the cell surface, which improved the stability of aFGF in hostile conditions. Moreover, AE-NPs significantly accelerated wound healing and improved collagen remodeling by regulating the TGF-β/Smad signaling pathway. Our results bring new insights into the field of polyphenol-containing nanoparticles, showing their potential as drug delivery systems of macromolecules to treat diabetic wounds.

Study on the effect of medicinal leech therapy (Hirudo medicinalis) on full-thickness excisional wound healing in the animal model

The possible impacts of alternative and conventional medicines on wound healing are now of growing interest. This study aimed to evaluate and elucidate the wound healing activity of medicinal leech therapy in wound excision of the rat model. After a round, full-thickness excision was made in the dorsal region of the body, the animals (n = 30) were randomly divided into three equal groups: I) the treatment group (MLT), where the wounds received leech treatment; II) the positive control group (PC), where the wounds received 1% sodium phenytoin treatment; and III) the negative control group (NC), where the wounds did not receive any treatment. On days 6 and 16, wound biopsy specimens were taken, and prepared sections were stained using various methods. The contraction rate differed significantly (P < 0.05) between the NC group and the other groups. The histopathological evaluation revealed that MLT group showed an accelerated healing process and lower inflammatory response compared to other groups. In ML-treated group maturation and remodeling of collagen had occurred, while in 1% sodium phenytoin treated group, proliferation was the prominent feature. Results showed that the fibroblast was significantly lower in the NC group in comparison to other groups. The number of MNC, s, and PMN, s was significantly higher in the NC group compared to other groups (P < 0.0001). In our study, medicinal leech therapy had a higher success rate in healing for the treatment of excisional wounds in animal models.

3D Bioprinting of Polythiophene Materials for Promoting Stem Cell Proliferation in a Nutritionally Deficient Environment.

3D printing of stem cells provides a tremendous opportunity to tissue engineering in regenerative medicine. However, developing new bioactive materials to rationally augment stem cell viability is still an enormous challenge owing to the nutritionally deficient environment caused by the limited-penetration distance of nutrition when cells are encapsulated within biomaterials. In this work, a cationic conjugated polythiophene derivative, poly[3-(3'-N,N,N-triethylamino-1'-propyloxy)-4-methyl-2,5-thiophene hydrochloride] (PMNT), is designed and integrated into an anionic gelatin/alginate matrix to develop a new 3D bioprintable conjugated polymer ink Gel/Alg/PMNT, while the electrostatic interaction can assist PMNT to anchor inside ink without severe diffusional loss. In principle, PMNT is confirmed to promote human umbilical cord-derived mesenchymal stem cell (hMSC) proliferation in a serum-free medium by driving cell cycles and up-regulating gene expression in the pathways of biosynthesis and the metabolism. By employing the 3D bioprinting strategy together with hMSCs, the accelerated healing of full-thickness excisional wounds is further realized through the augmented-stem cell therapeutics utilizing Gel/Alg/PMNT ink, in which hMSC proliferation can be effectively promoted upon inductive stimulation of PMNT. The inherent highly bioactive and robust proliferation-promoted nature of the developed conjugated polymer ink Gel/Alg/PMNT significantly overcomes the nutritionally deficient environment, especially in 3D-printed large-scale architectures. The bioactive polythiophene material exhibits a unique capacity to promote stem cell proliferation without the need of serum, providing a new bioink for 3D bioprinting in tissue reconstructions.

Effects of chitosan-collagen dressing on wound healing in vitro and in vivo assays.

The present study was designed to fabricate a new chitosan-collagen sponge (CCS) for potential wound dressing applications. CCS was fabricated by a 3.0% chitosan mixture with a 1.0% type I collagen (7:3(w/w)) through freeze-drying. Then the dressing was prepared to evaluate its properties through a series of tests. The new-made dressing demonstrated its safety toward NIH3T3 cells. Furthermore, the CCS showed the significant surround inhibition zone than empty controls inoculated by E. coli and S. aureus. Moreover, the moisture rates of CCS were increased more rapidly than the collagen and blank sponge groups. The results revealed that the CCS had the characteristics of nontoxicity, biocompatibility, good antibacterial activity, and water retention. We used a full-thickness excisional wound healing model to evaluate the in vivo efficacy of the new dressing. The results showed remarkable healing at 14th day post-operation compared with injuries treated with collagen only as a negative control in addition to chitosan only. Our results suggest that the chitosan-collagen wound dressing were identified as a new promising candidate for further wound application.

Physical and biological properties of blend-electrospun polycaprolactone/chitosan-based wound dressings loaded with N-decyl-N, N-dimethyl-1-decanaminium chloride: An in vitro and in vivo study.

Dual-pump electrospinning of antibacterial N-decyl-N, N-dimethyl-1-decanaminium-chloride (DDAC)-loaded polycaprolactone (PCL) nanofibers, and chitosan (CS)/polyethylene-oxide (PEO)-based wound dressings with hydrophilic and hydrophobic properties to eliminate and absorb pathogenic bacteria from wound surface besides antibacterial action and to support wound healing and accelerate its process. Physicochemical properties of the prepared nanofibrous mat as well as antibacterial, cytotoxicity, and cell compatibility were studied. The full-thickness excisional wound healing properties up to 3 weeks using hematoxylin and eosin and Masson-trichrome staining were investigated. Addition of DDAC to CS/PEO-PCL mats decreased the diameter of the nanofibers, which is a crucial property for wound healing as large surface area per volume ratio of nanofibers, in addition to proper cell adhesion, increases loading of DDAC in mats and leads to increased cell viability and eliminating Gram-positive bacteria at in vitro studies. In vivo studies showed DDAC-loaded CS/PEO-PCL mats increased epithelialization and angiogenesis and decreased the inflammation according to histological results. We demonstrated that hydrophobic PCL/DDAC mats, besides antibacterial properties of DDAC, absorbed and eliminated the hydrophobic pathological microorganisms, whereas the hydrophilic nanofibers consisted of CS/PEO, increased the cell adhesion and proliferation due to positive charge of CS. Finally, we were able to increase the wound healing quality by using multifunctional wound dressing. CS/PEO-PCL containing 8 wt % of DDAC nanofibrous mats is promising as a wound dressing for wound management due to the favorable interactions between the pathogenic bacteria and PCL/CS-based wound dressing.

Lipin-1 Contributes to IL-4 Mediated Macrophage Polarization.

Macrophage responses contribute to a diverse array of pathologies ranging from infectious disease to sterile inflammation. Polarization of macrophages determines their cellular function within biological processes. Lipin-1 is a phosphatidic acid phosphatase in which its enzymatic activity contributes to macrophage pro-inflammatory responses. Lipin-1 also possesses transcriptional co-regulator activity and whether this activity is required for macrophage polarization is unknown. Using mice that lack only lipin-1 enzymatic activity or both enzymatic and transcriptional coregulator activities from myeloid cells, we investigated the contribution of lipin-1 transcriptional co-regulator function toward macrophage wound healing polarization. Macrophages lacking both lipin-1 activities did not elicit IL-4 mediated gene expression to levels seen in either wild-type or lipin-1 enzymatically deficient macrophages. Furthermore, mice lacking myeloid-associated lipin-1 have impaired full thickness excisional wound healing compared to wild-type mice or mice only lacking lipin-1 enzymatic activity from myeloid cell. Our study provides evidence that lipin-1 transcriptional co-regulatory activity contributes to macrophage polarization and influences wound healing in vivo.

Treatment of Full-Thickness Skin Wounds with Blood-Derived CD34+ Precursor Cells Enhances Healing with Hair Follicle Regeneration.

Objective: Epidermal CD34+ stem cells located in the hair follicle (HF) bulge area are capable of inducing HF neogenesis and enhancing wound healing after transplantation. In this study, we observed CD34+ cells derived from blood directly participate in dermal regeneration during full-thickness excisional wound healing. Approach: We isolated and in vitro expanded a subset of hematopoietic stem cell (HSC)-like precursor cells from the peripheral blood of adult mice with the surface markers: CD34+, leucine rich repeat containing G protein-coupled receptor 5 (LGR5)+, CD44+, c-kit+, lineage negative (lin-), and E-cadherin-. These blood-derived precursor cells (BDPCs), can be further differentiated into epithelial-like cells (eBDPCs) and secret fibroblast growth factor 9 (Fgf9) protein. Result: When transplanted into full-thickness skin wounds, eBDPC treatment produced accelerated healing and enhanced skin structure regeneration with less dermal scar formation. Also, HF neogenesis (HFN) was observed with incorporation of labeled BDPCs in the wound area. Innovation:Nondermal-derived CD34+ cells (BDPCs) from the adult unmobilized peripheral blood are capable of in vitro expansion and differentiation.Successful establishment of an in vitro technical platform for BDPCs expansion and differentiation.The in vitro expanded and differentiated epithelial-like cells (eBDPCs) enhance wound healing and directly contribute to skin regeneration and HFN. Conclusion: BDPCs isolated and expanded from adult peripheral blood may provide a possible new cell-based treatment strategy for HF neogenesis and skin wound regeneration.

Newly Defined ATP-Binding Cassette Subfamily B Member 5 Positive Dermal Mesenchymal Stem Cells Promote Healing of Chronic Iron-Overload Wounds via Secretion of Interleukin-1 Receptor Antagonist.

In this study, we report the beneficial effects of a newly identified dermal cell subpopulation expressing the ATP-binding cassette subfamily B member 5 (ABCB5) for the therapy of nonhealing wounds. Local administration of dermal ABCB5+ -derived mesenchymal stem cells (MSCs) attenuated macrophage-dominated inflammation and thereby accelerated healing of full-thickness excisional wounds in the iron-overload mouse model mimicking the nonhealing state of human venous leg ulcers. The observed beneficial effects were due to interleukin-1 receptor antagonist (IL-1RA) secreted by ABCB5+ -derived MSCs, which dampened inflammation and shifted the prevalence of unrestrained proinflammatory M1 macrophages toward repair promoting anti-inflammatory M2 macrophages at the wound site. The beneficial anti-inflammatory effect of IL-1RA released from ABCB5+ -derived MSCs on human wound macrophages was conserved in humanized NOD-scid IL2rγ null mice. In conclusion, human dermal ABCB5+ cells represent a novel, easily accessible, and marker-enriched source of MSCs, which holds substantial promise to successfully treat chronic nonhealing wounds in humans. Stem Cells 2019;37:1057-1074.

Polyvinylpyrrolidone/hyaluronic acid-based bilayer constructs for sequential delivery of cutaneous antiseptic and antibiotic

After a skin injury, many complex metabolic events are triggered to ensure proper wound healing. Particularly for chronic, non-healing wounds or burns several risk factors such as persistent bacterial infections and fast dehydration can counteract the healing process. Intelligent wound dressings should help accelerate the healing process, while maintaining the wound bed clean and disinfected for several days at a time. Ideally, they should be self-adherent to both moist and dry skin surfaces and be transparent enough to allow prolonged wound inspection. These requirements pose challenges both in terms of materials science and pharmaceutics. Herein, we describe fabrication of a transparent bilayer construct for the sequential release and delivery of a cutaneous antiseptic and a widely used antibiotic, potentially suitable for wound dressing applications. The fabrication is a scalable waterborne and ecofriendly solution casting process. The first layer (for direct wound contact) is polyvinylpyrrolidone (PVP) containing a commercial antiseptic, Neomercurocromo® (Neo), while the second layer is a blend of hyaluronic acid (HA) and PVP containing ciprofloxacin. We show that the bilayer films have satisfactory self-adhering strength to human skin and that PVP and HA can interact via hydrogen bonds causing sustained release of the antibiotic over a period of 5 days. Biocompatibility was demonstrated on human foreskin fibroblast HFF-1 cells. Antibacterial activity was evaluated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa while the wound resorption behavior was assessed through an in vivo full-thickness excisional wound healing mice model. These observations indicate that such bilayer constructs can be potentially implemented as wound care products for diverse range of skin wounds, including large area skin infections.

Evaluation of Application of Chitosan/Nano Selenium Biodegradable Film on Full Thickness Excisional Wound Healing in Rats

Objective- This study aimed at evaluation of histopathological findings of application of chitosan- nano selenium biodegradable film on full thickness excisional wound healing in rats.Design- Experimental Study Animals- Seventy-two male Wistar rats Procedures- Animals were randomized into six groups of 12 animals each. Group I: Animals with created wounds and no further treatment. Group II: Animals with wounds were dressed with chitosan film only. Group III: Animals with wounds were treated with sodium selenite. Group IV: Animals with wounds were treated with sodium selenium nanoparticles. Group V: Animals with wounds were dressed with chitosan/ sodium selenite film. Group VI: Animals with wounds were dressed with chitosan/nano selenium film.Results- There were significant differences in comparisons of group VI and other groups, particularly in terms of cellular infiltration and neovascularization. During the study period, scores for neovascularization was significantly higher in group VI rats than other groups (P <0.05). Polymorphonuclear (PMN) and mononuclear (MNC) cell count and fibroblast cell proliferation in group VI were significantly higher than those of other experimental groups (P <0.05) Conclusion and Clinical Relevance- Chitosan/nano selenium biodegradable film resulted in significant improvement in histopathological indices in full-thickness wound healing. Thus, from this study it could be concluded that chitosan/nano selenium biodegradable film have a reproducible wound healing potential and hereby justifies its use in practice.

Effects of Plantago lanceolata L. extract on full-thickness excisional wound healing in a mouse model

Wound healing requires cells that increase both collagen production as a result of inflammatory events and regeneration of epithelial tissue. The Plantago species of herbs have been used in traditional treatment of skin disorders and infectious diseases, and digestive, respiratory, reproductive and circulatory conditions. We investigated the efficacy of different concentrations of Plantago lanceolata L. extract (PLE) for wound healing owing to its anti-inflammatory, anti-bacterial, anti-fungal, anti-oxidant, anti-ulcerative, analgesic and immunomodulatory properties. We used 72 mice in four groups of 18. An excisional 1 cm wound was created in the skin on the back of the mice in all groups. An ointment containing 10% PLE was applied to the wound in group 1, an ointment containing 20% PLE was applied in group 2 and vaseline was applied in group 3. In group 4, no treatment was applied to the wound. On days 7, 14, and 21 of the experiment, six animals in each group were sacrificed after the wounds were photographed and specimens from the wound sites were examined. On day 14, epithelialization was more prominent in group 2, while vascularization and collagen deposition was more advanced in groups 1 and 2 compared to the other groups. Immunohistochemical examination revealed that TGF-β1 expression was elevated on day 14 in all groups; however, this elevation was more limited in groups 1 and 2 than in groups 3 and 4. Although ANGPT-2 expression increased in groups 1 and 4 on day 14, it decreased significantly in groups 2 and 3. We found that different concentrations of PLE exhibited positive effects on wound healing. Application of 10% PLE ointment may be a useful strategy for wound healing.

Oleoyl-Chitosan-Based Nanofiber Mats Impregnated with Amniotic Membrane Derived Stem Cells for Accelerated Full-Thickness Excisional Wound Healing.

Wound healing management is a major challenge for critical full-thickness skin wounds. Development of nanofibrous scaffolds with tunable wettability, degradation, and biocompatibility are highly desirable. Herein, we demonstrated synthesis of oleoyl chitosan (OC) by grafting monounsaturated fatty acid residue, C18 oleoyl chain, to the backbone of chitosan molecule and blending with gelatin to form the nanofiber mats. The physicochemical properties of the nanofiber mats revealed mechanical strength, moderate surface wettability, and suitable degradation rate. The nanofibrous mats showed excellent in vitro cytocompatibility with human amniotic membrane-derived stem cells (HAMSCs) in terms of enhanced adhesion and proliferation owing to biomimetic nanoarchitecture and chemical cues. Furthermore, the fabricated nanofiber was implanted with and without preseeded HAMSCs in the full-thickness wound to evaluate the skin wound healing efficacy in a rat model. Histological and immunohistochemical studies were conducted to evaluate the plausible changes of tissue architecture and expression of molecular markers involved in wound healing process. Both acellular and HAMSCs incorporated cellular nanofibers promoted wound contraction remarkably with superior skin tissue regeneration in terms of enhanced collagen synthesis, re-epithelialization and initiation of epithelial cells stratification compared to control group.

ERBB3 is required for tumor promotion in a mouse model of skin carcinogenesis

The epidermal growth factor receptor (EGFR) plays a key role in skin inflammation, wound healing, and carcinogenesis. Less is known about the functions of the structurally related receptor ERBB3 (HER3) in the skin. We assessed the requirement of ERBB3 for skin homeostasis, wound healing, and tumorigenesis by crossing mice carrying a conditional Erbb3 allele with animals expressing cre under the control of the keratin 5 promoter. Erbb3del mice, lacking ERBB3 specifically in keratinocytes, showed no obvious abnormalities. The EGFR was upregulated in Erbb3del skin, possibly compensating the loss of ERBB3. Nonetheless, healing of full-thickness excisional wounds was negatively affected by ERBB3 deficiency. To analyze the function of ERBB3 during tumorigenesis, we employed the established DMBA/TPA multi-stage chemical carcinogenesis protocol. Erbb3del mice remained free of papillomas for a longer time and had significantly reduced tumor burden compared to control littermates. Tumor cell proliferation was considerably reduced in Erbb3del mice, and loss of ERBB3 also impaired keratinocyte proliferation after a single application of TPA. In human skin tumor samples, upregulated ERBB3 expression was observed in squamous cell carcinoma, condyloma, and malignant melanoma. Thus, we conclude that ERBB3, while dispensable for the development and the homeostasis of the epidermis and its appendages, is required for proper wound healing and for the progression of skin tumors during multi-stage chemical carcinogenesis in mice. ERBB3 may also be important for human skin cancer progression. The latter effects most probably reflect a key role for ERBB3 in increasing cell proliferation after stimuli as wounding or carcinogenesis.

Specific effects of fibrinogen and the γA and γ'-chain fibrinogen variants on angiogenesis and wound healing.

In a newly formed wound, the natural fibrin network provides the first temporary matrix for tissue repair. Topical application of fibrin to a new wound may improve wound healing. A matrix of the common natural γ' fibrin variant may further improve wound healing because it is expected to have a different architecture and this will influence angiogenesis, because it possesses increased thrombin and factor XIII binding and decreased platelet binding, when compared with the common γA fibrin matrix. Our objective was to determine the effect of fibrinogen and its γA and γ' variants on angiogenesis and wound healing. We used in vitro angiogenesis models and an in vivo rat full-thickness excisional wound healing model. When comparing γA and γ' fibrin in vitro, more tube-like structures were formed on day 7 in γA fibrin than in γ' fibrin (13.83±6.12 AU vs. 6.1±1.46 AU). Wounds treated with fibrin demonstrated improved healing in vivo with more perfusion (47%±3% vs. 26%±4%, p<0.01 in placebo) and higher CD34 density score (2.0±0.4 vs. 2.8±0.1, p<0.01) on day 21 with fibrin matrices when compared with placebo-treated wounds. Increased perfusion was observed in γA fibrin-treated wounds on day 21 (53%±10% vs. 41%±7% for γ' fibrin). The other parameters showed slightly improved (not significant) wound healing with γA fibrin compared with γ' fibrin matrices. In conclusion, the use of fibrin and fibrin variant matrices offers an interesting methodology to stimulate the wound healing process.

A novel small compound accelerates dermal wound healing by modifying infiltration, proliferation and migration of distinct cellular components in mice

BackgroundImpaired wound healing in skin ulcer is one of the major medical issues in the aged society. Wound healing is a complex process orchestrated by a number of humoral factors and cellular components. TGF-β is known to stimulate collagen production in dermal fibroblasts while inhibiting proliferation of epidermal keratinocyte. A screening of small compounds that suppress type I collagen production in fibroblasts has identified HSc025 that antagonizes the TGF-β/Smad signal. ObjectiveWe examined the effects of HSc025 on dermal wound healing and elucidated the underlying mechanisms. MethodsEffects of HSc025 on the wound closure process were evaluated in a murine full-thickness excisional wound healing model. Cell proliferation and migration were estimated using primary cultures of human keratinocytes and fibroblasts. Comprehensive analyses of gene expression profiles were performed using untreated and HSc025-treated fibroblasts. ResultsOral HSc025 administration suppressed macrophage infiltration and accelerated wound closure as early as at day 2 after the dermal excision. Treatment of cultured keratinocytes with HSc025 counteracted the inhibitory effects of TGF-β on cell proliferation and migration. On the other hand, HSc025 stimulated migration, but not proliferation, of dermal fibroblasts independently of TGF-β. Experiments using an artificial dermis graft revealed that HSc025 stimulated migration of collagen-producing cells into the graft tissue. A cDNA microarray analysis of untreated and HSc025-treated fibroblasts identified pirin as a critical mediator accelerating fibroblast migration. ConclusionHSc025 accelerates wound healing by modifying infiltration, proliferation and migration of distinct cellular components, which provides a novel insight into the therapy for intractable skin ulcer.

Combined effect of PLGA and curcumin on wound healing activity

Wound healing is a complex process involving many interdependent and overlapping sequences of physiological actions. The application of exogenous lactate released from poly (lactic-co-glycolic acid) (PLGA) polymer accelerated angiogenesis and wound healing processes. Curcumin is a well-known topical wound healing agent for both normal and diabetic-impaired wounds. Hence, we hypothesized that the PLGA nanoparticles encapsulating curcumin could much potentially accelerate the wound healing. In a full thickness excisional wound healing mouse model, PLGA–curcumin nanoparticles showed a twofold higher wound healing activity compared to that of PLGA or curcumin. Histology and RT-PCR studies confirmed that PLGA–curcumin nanoparticles exhibited higher re-epithelialization, granulation tissue formation and anti-inflammatory potential. PLGA nanoparticles offered various benefits for the encapsulated curcumin like protection from light degradation, enhanced water solubility and showed a sustained release of curcumin over a period of 8days. In conclusion, we demonstrated the additive effect of lactic acid from PLGA and encapsulated curcumin for the active healing of wounds.

RhEGF-loaded PLGA-Alginate microspheres enhance the healing of full-thickness excisional wounds in diabetised Wistar rats

Diabetic foot ulcers (DFUs) represent a major clinical challenge in the ageing population. To address this problem, rhEGF-loaded Poly-Lactic-co-Glycolic-Acid (PLGA)-Alginate microspheres (MS) were prepared by a modified w/o/w-double-emulsion/solvent evaporation method. Different formulations were evaluated with the aim of optimising MSs properties by adding NaCl to the surfactant solution and/or the solvent removal phase and adding alginate as a second polymer. The characterisation of the developed MS showed that alginate incorporation increased the encapsulation efficiency (EE) and NaCl besides increasing the EE also became the particle surface smooth and regular. Once the MS were optimised, the target loading of rhEGF was increased to 1% (PLGA-Alginate MS), and particles were sterilised by gamma radiation to provide the correct dosage for in vivo studies. In vitro cell culture assays demonstrated that neither the microencapsulation nor the sterilisation process affected rhEGF bioactivity or rhEGF wound contraction. Finally, the MS were evaluated in vivo for treatment of the full-thickness wound model in diabetised Wistar rats. rhEGF MS treated animals showed a statistically significant decrease of the wound area by days 7 and 11, a complete re-epithelisation by day 11 and an earlier resolution of the inflammatory process. Overall, these findings demonstrate the promising potential of rhEGF-loaded MS (PLGA-Alginate MS) to promote faster and more effective wound healing, and suggest its possible application in DFU treatment.

Exogenous calreticulin improves diabetic wound healing

A serious consequence of diabetes mellitus is impaired wound healing, which largely resists treatment. We previously reported that topical application of calreticulin (CRT), an endoplasmic reticulum chaperone protein, markedly enhanced the rate and quality of wound healing in an experimental porcine model of cutaneous repair. Consistent with these in vivo effects, in vitro CRT induced the migration and proliferation of normal human cells critical to the wound healing process. These functions are particularly deficient in poor healing diabetic wounds. Using a genetically engineered diabetic mouse (db/db) in a full-thickness excisional wound healing model, we now show that topical application of CRT induces a statistically significant decrease in the time to complete wound closure compared with untreated wounds by 5.6 days (17.6 vs. 23.2). Quantitative analysis of the wounds shows that CRT increases the rate of reepithelialization at days 7 and 10 and increases the amount of granulation tissue at day 7 persisting to day 14. Furthermore, CRT treatment induces the regrowth of pigmented hair follicles observed on day 28. In vitro, fibroblasts isolated from diabetic compared with wild-type mouse skin and human fibroblasts cultured under hyperglycemic compared with normal glucose conditions proliferate and strongly migrate in response to CRT compared with untreated controls. The in vitro effects of CRT on these functions are consistent with CRT's potent effects on wound healing in the diabetic mouse. These studies implicate CRT as a potential powerful topical therapeutic agent for the treatment of diabetic and other chronic wounds.

Cultured Keratinocytes on Urinary Bladder Matrix Scaffolds Increase Angiogenesis and Help in Rapid Healing of Wounds

Urinary Bladder Matrix (UBM) is an extracellular matrix (ECM) scaffold. It is now used in wound care management of partial and full-thickness wounds where conventional methods for wound care usually fail to give satisfactory results. In this study, the authors are comparing the healing of full-thickness excisional wounds in New Zealand rabbits using either UBM scaffolds alone or in combination with cultured keratinocytes. The wounds were compared grossly and histologically. It is a comparative controlled study including 40 full-thickness wounds in 2 groups. Group (A) wounds: treated with UBM scaffolds, Group (B) wounds: treated with UBM scaffolds with cultured keratinocytes. The wounds were examined grossly after 1, 2, and 3 weeks, and were examined histologically at the end of the 3rd week using ordinary hematoxylin-eosin staining techniques. All the wounds healed completely by the end of the 3rd week. Early wound contraction was significantly less in group B. More angiogenic response was evident in all specimens of group B. This study shows that adding cultured keratinocytes to the rough surface of the UBM scaffold may be beneficial in reducing early wound contraction and improving wound vascularity in treatment of full-thickness wounds.