Hyaluronidase modulates inflammatory response and accelerates the cutaneous wound healing

All-trans retinoic acid pretreatment of mesenchymal stem cells enhances the therapeutic effect on acute kidney injury

A promising new therapy option for acute kidney injury (AKI) is mesenchymal stem cells (MSCs). However, there are several limitations to the use of MSCs, such as low rates of survival, limited homing capacity, and unclear differentiation. In search of better therapeutic strategies, we explored all-trans retinoic acid (ATRA) pretreatment of MSCs to observe whether it could improve the therapeutic efficacy of AKI. We established a renal ischemia/reperfusion injury model and treated mice with ATRA-pretreated MSCs via tail vein injection. We found that AKI mice treated with ATRA-MSCs significantly improved renal function compared with DMSO-MSCs treatment. RNA sequencing screened that hyaluronic acid (HA) production from MSCs promoted by ATRA. Further validation by chromatin immunoprecipitation experiments verified that retinoic acid receptor RARα/RXRγ was a potential transcription factor for hyaluronic acid synthase 2. Additionally, an in vitro hypoxia/reoxygenation model was established using human proximal tubular epithelial cells (HK-2). After co-culturing HK-2 cells with ATRA-pretreated MSCs, we observed that HA binds to cluster determinant 44 (CD44) and activates the PI3K/AKT pathway, which enhances the anti-inflammatory, anti-apoptotic, and proliferative repair effects of MSCs in AKI. Inhibition of the HA/CD44 axis effectively reverses the renal repair effect of ATRA-pretreated MSCs. Taken together, our study suggests that ATRA pretreatment promotes HA production by MSCs and activates the PI3K/AKT pathway in renal tubular epithelial cells, thereby enhancing the efficacy of MSCs against AKI.

Cancer immunometabolism: advent, challenges, and perspective

For decades, great strides have been made in the field of immunometabolism. A plethora of evidence ranging from basic mechanisms to clinical transformation has gradually embarked on immunometabolism to the center stage of innate and adaptive immunomodulation. Given this, we focus on changes in immunometabolism, a converging series of biochemical events that alters immune cell function, propose the immune roles played by diversified metabolic derivatives and enzymes, emphasize the key metabolism-related checkpoints in distinct immune cell types, and discuss the ongoing and upcoming realities of clinical treatment. It is expected that future research will reduce the current limitations of immunotherapy and provide a positive hand in immune responses to exert a broader therapeutic role.

Multi-System-Level Analysis Reveals Differential Expression of Stress Response-Associated Genes in Inflammatory Solar Lentigo

Although the pathogenesis of solar lentigo (SL) involves chronic ultraviolet (UV) exposure, cellular senescence, and upregulated melanogenesis, underlying molecular-level mechanisms associated with SL remain unclear. The aim of this study was to investigate the gene regulatory mechanisms intimately linked to inflammation in SL. Skin samples from patients with SL with or without histological inflammatory features were obtained. RNA-seq data from the samples were analyzed via multiple analysis approaches, including exploration of core inflammatory gene alterations, identifying functional pathways at both transcription and protein levels, comparison of inflammatory module (gene clusters) activation levels, and analyzing correlations between modules. These analyses disclosed specific core genes implicated in oxidative stress, especially the upregulation of nuclear factor kappa B in the inflammatory SLs, while genes associated with protective mechanisms, such as SLC6A9, were highly expressed in the non-inflammatory SLs. For inflammatory modules, Extracellular Immunity and Mitochondrial Innate Immunity were exclusively upregulated in the inflammatory SL. Analysis of protein-protein interactions revealed the significance of CXCR3 upregulation in the pathogenesis of inflammatory SL. In conclusion, the upregulation of stress response-associated genes and inflammatory pathways in response to UV-induced oxidative stress implies their involvement in the pathogenesis of inflammatory SL.

Assessment of wound healing activity in diabetic mice treated with a novel therapeutic combination of selenium nanoparticles and platelets rich plasma

Diabetic wound healing is sluggish, often ending in amputations. This study tested a novel, two-punch therapy in mice-Selenium nanoparticles (Se NPs) and platelet-rich plasma (PRP)-to boost healing. First, a mouse model of diabetes was created. Then, Se NPs were crafted for their impressive antioxidant and antimicrobial powers. PRP, packed with growth factors, was extracted from the mice's blood. Wound healing was tracked for 28 days through photos, scoring tools, and tissue analysis. Se NPs alone spurred healing, and PRP added extra fuel. Furthermore, when used in combination with PRP, the healing process was accelerated due to the higher concentration of growth factors in PRP. Notably, the combination of Se NPs and PRP exhibited a synergistic effect, significantly enhancing wound healing in diabetic mice. These findings hold promise for the treatment of diabetic wounds and have the potential to reduce the need for lower limb amputations associated with diabetic foot ulcers. The innovative combination therapy using Se NPs and PRP shows great potential in expediting the healing process and addressing the challenges of impaired wound healing in individuals with diabetes. This exciting finding suggests this therapy could change diabetic wound management, potentially saving limbs and improving lives.

Navigating Treatment Dilemmas: Recalcitrant Pemphigus and the Burden of Multiple Comorbidities

Pemphigus vulgaris is a chronic autoimmune disease of the skin caused by the production of autoantibodies targeting desmogleins 1 and 3 usually presenting in individuals with an average age of onset of approximately 40 years. A 35-year-old obese, diabetic woman presented with fluid-filled lesions over her body for three months along with erosions and painful ulcers in her mouth and genital area for two months. Based on clinical and histopathological studies, the patient was diagnosed as a case of pemphigus vulgaris. She was started on conventional treatment with oral corticosteroids followed by pulse therapy and mycophenolate mofetil. Rituximab infusion was scheduled but could not be administered due to elevated D-dimer values. The patient underwent screening for deep vein thrombosis (DVT) and received subcutaneous enoxaparin and oral rivaroxaban. She developed severe sepsis for which she was treated with systemic antibiotics. She subsequently developed acute renal failure and underwent hemodialysis. The patient's clinical condition further deteriorated, which necessitated therapeutic plasma exchange (TPE). Collagen, colloidal silver, and silicone foam dressings were done to hasten wound healing. Two distinct approaches were employed to eliminate the pseudomembrane on the wounds. One portion was treated with hydrogen peroxide (H2O2), while the other was with hyaluronidase. The hyaluronidase treatment resulted in considerable improvement of the lesions. Intravenous immunoglobulin (IVIG) infusion was scheduled. However, the treatment could not be administered as the patient succumbed to death due to pulmonary thromboembolism (PTE) secondary to DVT.

Bacterial cellulose membrane incorporated with silver nanoparticles for wound healing in animal model

The bacterial cellulose membrane (CM) is a promising biomaterial due to its easy applicability and moist environment. Moreover, nanoscale silver compounds (AgNO₃) are synthesized and incorporated into CMs to provide these biomaterials with antimicrobial activity for wound healing. This study aimed to evaluate the cell viability of CM incorporated with nanoscale silver compounds, determine the minimum inhibitory concentration (MIC) for Escherichia coli and Staphylococcus aureus, and its use on in vivo skin lesions. Wistar rats were divided according to treatment: untreated, CM (cellulose membrane), and AgCM (CM incorporated with silver nanoparticles). The euthanasia was performed on the 2nd, 7th, 14th, and 21st days to assess inflammation (myeloperoxidase-neutrophils, N-acetylglucosaminidase-macrophage, IL-1β, IL-10), oxidative stress (NO-nitric oxide, DCF-H₂O₂), oxidative damage (carbonyl: membrane's damage; sulfhydryl: membrane's integrity), antioxidants (superoxide dismutase; glutathione), angiogenesis, tissue formation (collagen, TGF-β1, smooth muscle α-actin, small decorin, and biglycan proteoglycans). The use of AgCM did not show toxicity, but antibacterial effect in vitro. Moreover, in vivo, AgCM provided balanced oxidative action, modulated the inflammatory profile due to the reduction of IL-1β level and increase in IL-10 level, in addition to increased angiogenesis and collagen formation. The results suggest the use of silver nanoparticles (AgCM) enhanced the CM properties by providing antibacterial properties, modulation the inflammatory phase, and consequently promotes the healing of skin lesions, which can be used clinically to treat injuries.

Photobiomodulation at 660 nm Stimulates In Vitro Diabetic Wound Healing via the Ras/MAPK Pathway

Diabetic foot ulcers (DFUs) are open chronic wounds that affect diabetic patients due to hyperglycaemia. DFUs are known for their poor response to treatment and frequently require amputation, which may result in premature death. The present study evaluated the effect of photobiomodulation (PBM) at 660 nm on wound healing via activation of Ras/MAPK signalling in diabetic wounded cells in vitro. This study used four human skin fibroblast cell (WS1) models, namely normal (N), wounded (W), diabetic (D), and diabetic wounded (DW). Cells were irradiated at 660 nm with 5 J/cm2. Non-irradiated cells (0 J/cm2) served as controls. Cells were incubated for 24 and 48 h post-irradiation, and the effect of PBM on cellular morphology and migration rate, viability, and proliferation was assessed. Basic fibroblast growth factor (bFGF), its phosphorylated (activated) receptor FGFR, and phosphorylated target proteins (Ras, MEK1/2 and MAPK) were determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting; nuclear translocation of p-MAPK was determined by immunofluorescence. PBM resulted in an increase in bFGF and a subsequent increase in FGFR activation. There was also an increase in downstream proteins, p-Ras, p-MEK1/2 and p-MAPK. PBM at 660 nm led to increased viability, proliferation, and migration as a result of increased bFGF and subsequent activation of the Ras/MAPK signalling pathway. Therefore, this study can conclude that PBM at 660 nm stimulates in vitro diabetic wound healing via the bFGF-activated Ras/MAPK pathway.

The use of occlusive dressings: influence on excisional wound healing in animal model

PURPOSE

To analyze the influence of occlusive dressing on the healing of excisional skin wounds in mice.

METHODS

Pre-clinical, comparative, and translational study. Mice were divided into three experimental groups: wounds occluded with hydrocolloid (HD) dressings, transparent polyurethane film (TF) dressings, and without occlusion (WO), monitored at three, six and 14 days, with eight animals each. Closure rate, infiltration of neutrophils and macrophages, measurement of tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) and, histologically, angiogenesis were evaluated.

RESULTS

Wound closure was accelerated in the occlusive groups. There was a decrease in TNF-α levels in the HD group when compared to the WO and TF groups. Neutrophils accumulation decreased in the HD group. Increased dosages of macrophages were evidenced in the HD group, compared to the WO and TF groups. Levels of VEGF were increased in the TF and HD groups.

CONCLUSIONS

It is suggested that the occlusion of wounds modulates the inflammatory response.

Efficacy of submucosal injection of hyaluronidase after mandibular third molar surgery: a randomized controlled trial

Objectives

This study aimed to investigate the efficacy of postoperative submucosal injection of hyaluronidase (HUD) for reducing sequelae and quality of life (QOL) after mandibular third molar (M3M) surgery.

Materials and Methods

Participants with bilateral impacted M3M underwent surgical extraction with a split-mouth randomized controlled study design. M3M were removed by the same surgeon in 2 sessions, one a control and the other experimental. Submucosal injection of HUD was performed in the experimental session and submucosal injection of saline in the control session. Mouth opening, facial swelling, and pain intensity were measured before surgery, and then 2 and 7 days after surgery. The QOL of participants following surgery was evaluated by means of a patient-centered outcome questionnaire (PCOQ).

Results

A total of 36 patients was included in the final data analysis. There was a significant reduction in the maximal mouth opening and postoperative pain in the experimental side at the 2 and 7 days after surgery (P<0.05), and a remarkable difference in facial swelling was reported on the experimental side 7 days after surgery (P<0.05). The PCOQ demonstrated that participants reported less pain and swelling on the experimental side.

Conclusion

The present study provides clinical evidence that submucosal administration of HUD immediately after M3M surgery reduced postoperative discomfort and improved patients' QOL.

Redox Properties, Bioactivity and Health Effects of Indicaxanthin, a Bioavailable Phytochemical from Opuntia ficus indica, L.: A Critical Review of Accumulated Evidence and Perspectives

Phytochemicals from plant foods are considered essential to human health. Known for their role in the adaptation of plants to their environment, these compounds can induce adaptive responses in cells, many of which are directed at maintaining the redox tone. Indicaxanthin is a long-known betalain pigment found in the genus Opuntia of cactus pear and highly concentrated in the edible fruits of O. ficus indica, L. whose bioactivity has been overlooked until recently. This review summarizes studies conducted so far in vitro and in vivo, most of which have been performed in our laboratory. The chemical and physicochemical characteristics of Indicaxanthin are reflected in the molecule's reducing properties and antioxidant effects and help explain its ability to interact with membranes, modulate redox-regulated cellular pathways, and possibly bind to protein molecules. Measurement of bioavailability in volunteers has been key to exploring its bioactivity; amounts consistent with dietary intake, or plasma concentration after dietary consumption of cactus pear fruit, have been used in experimental setups mimicking physiological or pathophysiological conditions, in cells and in animals, finally suggesting pharmacological potential and relevance of Indicaxanthin as a nutraceutical. In reporting experimental results, this review also aimed to raise questions and seek insights for further basic research and health promotion applications.

Towards the Preparation of a Hydrogel from Lyophilisates of the Aloe arborescens Aqueous Extract

Aloe gel is a medicinal raw material with proven pharmacological activity. The health-promoting properties of other species of Aloe upon topical application prompted us to develop a formulation for the topical application of A. arborescence species. As a result of the gel preparation from the aqueous lyophilized extracts of three-year-old leaves of A. arborescence, no changes in the composition of the content of aloins A and aloenin A were found. The potential to neutralize free radicals was tested using DPPH and CUPRAC techniques, which confirmed the anti-radical activity of the lyophilisate. Screening of the inhibition of enzymes, the hyperactivity of which is associated with adverse changes in the skin of a pro-inflammatory nature, was performed. Importantly, using the PAMPA SKIN model, the possibility of the penetration of selected extract compounds (aloin A and aloenin A) through the skin was proven. Then, two formulations were prepared based on sodium alginate and hydroxypropyl methylcellulose (HPMC) and the hydrogels were characterized (rheological analysis, drug release profiles, permeability, and stability studies). HPMC-based hydrogel was the one with a targeted release of active substances and greater stability. Aloe arborescens hydrogel matrices seem to be a promising treatment strategy for inflammatory surface damage based on “green technology” at the stage of extract preparation and development of the drug form for topical application.

The Impact of Hyaluronan on Tumor Progression in Cutaneous Melanoma

The incidence of cutaneous melanoma is rapidly increasing worldwide. Cutaneous melanoma is an aggressive type of skin cancer, which originates from malignant transformation of pigment producing melanocytes. The main risk factor for melanoma is ultraviolet (UV) radiation, and thus it often arises from highly sun-exposed skin areas and is characterized by a high mutational burden. In addition to melanoma-associated mutations such as BRAF, NRAS, PTEN and cell cycle regulators, the expansion of melanoma is affected by the extracellular matrix surrounding the tumor together with immune cells. In the early phases of the disease, hyaluronan is the major matrix component in cutaneous melanoma microenvironment. It is a high-molecular weight polysaccharide involved in several physiological and pathological processes. Hyaluronan is involved in the inflammatory reactions associated with UV radiation but its role in melanomagenesis is still unclear. Although abundant hyaluronan surrounds epidermal and dermal cells in normal skin and benign nevi, its content is further elevated in dysplastic lesions and local tumors. At this stage hyaluronan matrix may act as a protective barrier against melanoma progression, or alternatively against immune cell attack. While in advanced melanoma, the content of hyaluronan decreases due to altered synthesis and degradation, and this correlates with poor prognosis. This review focuses on hyaluronan matrix in cutaneous melanoma and how the changes in hyaluronan metabolism affect the progression of melanoma.

Neomenthol prevents the proliferation of skin cancer cells by restraining tubulin polymerization and hyaluronidase activity

Introduction

Neomenthol, a cyclic monoterpenoid, is a stereoisomer of menthol present in the essential oil of Mentha spp. It is used in food as a flavoring agent, in cosmetics and medicines because of its cooling effects. However, neomenthol has not been much explored for its anticancer potential. Additionally, targeting hyaluronidase, Cathepsin-D, and ODC by phytochemicals is amongst the efficient approach for cancer prevention and/or treatment.

Objectives

To investigate the molecular and cell target-based antiproliferative potential of neomenthol on human cancer (A431, PC-3, K562, A549, FaDu, MDA-MB-231, COLO-205, MCF-7, and WRL-68) and normal (HEK-293) cell lines.

Methods

The potency of neomenthol was evaluated on human cancer and normal cell line using SRB, NRU and MTT assays. The molecular target based study of neomenthol was carried out in cell-free and cell-based test systems. Further, the potency of neomenthol was confirmed by quantitative real-time PCR analysis and molecular docking studies. The in vivo anticancer potential of neomenthol was performed on mice EAC model and the toxicity examination was accomplished through in silico, ex vivo and in vivo approaches.

Results

Neomenthol exhibits a promising activity (IC₅₀ 17.3 ± 6.49 μM) against human epidermoid carcinoma (A431) cells by arresting the G2/M phase and increasing the number of sub-diploid cells. It significantly inhibits hyaluronidase activity (IC₅₀ 12.81 ± 0.01 μM) and affects the tubulin polymerization. The expression analysis and molecular docking studies support the in vitro molecular and cell target based results. Neomenthol prevents EAC tumor formation by 58.84% and inhibits hyaluronidase activity up to 10% at 75 mg/kg bw, i.p. dose. The oral dose of 1000 mg/kg bw was found safe in acute oral toxicity studies.

Conclusion

Neomenthol delayed the growth of skin carcinoma cells by inhibiting the tubulin polymerization and hyaluronidase activity, which are responsible for tumor growth, metastasis, and angiogenesis.

Angiogenic potential and wound healing efficacy of chitosan derived hydrogels at varied concentrations of APTES in chick and mouse models

Chitosan (Cs) based biomaterials seem to be indispensable for neovasculogenesis and angiogenesis that ensure accelerated wound healing. Cs/poly (vinyl alcohol) (PVA) bio-constructs were cross-linked and investigated with varying concentrations of aminopropyltriethoxysilane (APTES). This study comprised of three phases: fabrication of hydrogels, characterization, assessment of angiogenic potential along with toxico-pathological effects, wound healing efficacy in chick and mice, respectively. The hydrogels were characterized by FTIR, SEM and TGA and the swelling response was examined in different solvents. The hydrogels swelling ratio was decreased with increasing amount of APTES, showed the highest swelling at acidic and basic pH while low swelling at neutral pH. Chorioallantoic membranes (CAM) assay was performed to study in-vivo angiogenesis, toxicological, morphological, biochemical and histological analyses in developing chicks. The results showed remarkably improved angiogenesis with little deviations in morphological, histological features and liver enzymes of chick embryos at higher concentrations of APTES. Besides, full thickness wounds were excised on mice dorsolateral skin to assess the wound healing. The rate of wound size reduction was significantly higher after topical application of hydrogels with elevated levels of crosslinker. Hence, the hydrogels showed enhanced angiogenesis, accelerated wound healing with little or no observable in-vivo toxicity.

Hyaluronan Functions in Wound Repair That Are Captured to Fuel Breast Cancer Progression

Signaling from an actively remodeling extracellular matrix (ECM) has emerged as a critical factor in regulating both the repair of tissue injuries and the progression of diseases such as metastatic cancer. Hyaluronan (HA) is a major component of the ECM that normally functions in tissue injury to sequentially promote then suppress inflammation and fibrosis, a duality in which is featured, and regulated in, wound repair. These essential response-to-injury functions of HA in the microenvironment are hijacked by tumor cells for invasion and avoidance of immune detection. In this review, we first discuss the numerous size-dependent functions of HA and emphasize the multifunctional nature of two of its receptors (CD44 and RHAMM) in regulating the signaling duality of HA in excisional wound healing. This is followed by a discussion of how HA metabolism is de-regulated in malignant progression and how targeting HA might be used to better manage breast cancer progression.

Use of hyaluronidase in plastic surgery: A review

Hyaluronidase is a family of enzymes that degrade hyaluronic acid (HA). It is found to increase vascular permeability and temporarily disrupt the extracellular matrix, promoting diffusion of substances through tissues. Alongside its applications in ophthalmology, obstetrics and gynaecology, musculoskeletal medicine, radiology and drug and fluid administration, hyaluronidase has a number of roles in the field of plastic surgery. The popularity of HA fillers in recent years has led to an increase in the usage of hyaluronidase in the treatment of filler-related complications. The purpose of this article is to review the current and future uses of hyaluronidase within the field of plastic surgery. Hyaluronidase is used as an adjunct to local anaesthetics in skin infiltration, skin graft harvesting, tumescent analgesia, managing complications of dermal fillers, treatment of extravasation injury, prevention and management of oedema, treatment of ganglion and management of scars. However, it has some limitations. Hyaluronidase is known to interact with a number of common medications. Several case reports also highlight the risk of allergic reaction to the substance. Although rare and usually mild, hyaluronidase has the potential to cause anaphylaxis. Other adverse effects include bruising and swelling. Overall, hyaluronidase appears to be a very safe, cheap and effective medication for a variety of uses in the field of plastic surgery and beyond.

In vitro and in vivo anti-inflammatory activity and chemical composition of Renealmia petasites Gagnep

The study aimed to investigate the chemical composition and the anti-inflammatory activity of the hydroethanolic rhizomes, stems, and leaf extracts of Renealmia petasites using in vitro and in vivo assays. The chemical composition of the extracts was characterized in a linear iron trap mass spectrometer. Total phenolic, flavonoid, and tannin content were determined by spectrophotometry analyses. In vitro anti-inflammatory activity was investigated in lipopolysaccharide-stimulated macrophages evaluating the influence on the production of superoxide anion (O₂^-), nitric oxide (NO), and the pro-inflammatory cytokines tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). In vivo effects were determined using the air pouch model in which were inoculated carrageenan and thereafter treated with 50 mg/kg of the hydroethanolic extracts of R. petasites. After 4 and 24 h, the cellular influx, protein exudation, cytokines, and nitric oxide were evaluated. Eight compounds were tentatively identified in the R. petasites extracts, suggesting five diarylheptanoids, one flavonoid, and two fatty alcohols. The in vitro results showed that the extracts were capable of blocking free radicals and/or inhibiting their intracellular actions by inhibiting the production of important mediators of the inflammatory process, such as NO, O₂^-, TNF-α, and IL-6. In vivo, R. petasites significantly decrease the influx of leukocytes, mainly neutrophils, protein exudation, NO, TNF-α, and IL-6 concentration in the air pouch model. The results evidenced that R. petasites can be considered a promising alternative therapy for the treatment and management of osteoarthritis and other inflammatory diseases.

Dose- and time-dependent effects of hyaluronidase on structural cells and the extracellular matrix of the skin

Introduction

Hyaluronic acid (hyaluronan; HA) is an essential component of the extracellular matrix (ECM) of the skin. The HA-degrading enzyme hyaluronidase (HYAL) is critically involved in the HA-metabolism. Yet, only little information is available regarding the skin’s HA–HYAL interactions on the molecular and cellular levels.

Objective

To analyze the dose- and time-dependent molecular and cellular effects of HYAL on structural cells and the HA-metabolism in the skin.

Materials and methods

Chip-based, genome-wide expression analyses (Affymetrix® GeneChip PrimeView™ Human Gene Expression Array), quantitative real-time PCR analyses, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (DAB), and in vitro wound healing assays were performed to assess dose-dependent and time-kinetic effects of HA and HYAL (bovine hyaluronidase, Hylase “Dessau”) on normal human dermal fibroblasts (NHDF), primary human keratinocytes in vitro and human skin samples ex vivo.

Results

Genome-wide expression analyses revealed an upregulation of HA synthases (HAS) up to 1.8-fold change in HA- and HYAL-treated NHDF. HA and HYAL significantly accelerated wound closure in an in vitro model for cutaneous wound healing. HYAL induced HAS1 and HAS2 mRNA gene expression in NHDF. Interestingly, low concentrations of HYAL (0.015 U/ml) resulted in a significantly higher induction of HAS compared to moderate (0.15 and 1.5 U/ml) and high concentrations (15 U/ml) of HYAL. This observation corresponded to increased concentrations of HA measured by ELISA in conditioned supernatants of HYAL-treated NHDF with the highest concentrations observed for 0.015 U/ml of HYAL. Finally, immunohistochemical analysis of human skin samples incubated with HYAL for up to 48 h ex vivo demonstrated that low concentrations of HYAL (0.015 U/ml) led to a pronounced accumulation of HA, whereas high concentrations of HYAL (15 U/ml) reduced dermal HA-levels.

Conclusion

HYAL is a bioactive enzyme that exerts multiple effects on the HA-metabolism as well as on the structural cells of the skin. Our results indicate that HYAL promotes wound healing and exerts a dose-dependent induction of HA-synthesis in structural cells of the skin. Herein, interestingly the most significant induction of HAS and HA were observed for the lowest concentration of HYAL.

Hyaluronan: Metabolism and Function

As a major polysaccharide component of the extracellular matrix, hyaluronan plays essential roles in the organization of tissue architecture and the regulation of cellular functions, such as cell proliferation and migration, through interactions with cell-surface receptors and binding molecules. Metabolic pathways for biosynthesis and degradation tightly control the turnover rate, concentration, and molecular size of hyaluronan in tissues. Despite the relatively simple chemical composition of this polysaccharide, its wide range of molecular weights mediate diverse functions that depend on molecular size and tissue concentration. Genetic engineering and pharmacological approaches have demonstrated close associations between hyaluronan metabolism and functions in many physiological and pathological events, including morphogenesis, wound healing, and inflammation. Moreover, emerging evidence has suggested that the accumulation of hyaluronan extracellular matrix and fragments due to the altered expression of hyaluronan synthases and hyaluronidases potentiates cancer development and progression by remodeling the tumor microenvironment. In addition to the well-known functions exerted by extracellular hyaluronan, recent metabolomic approaches have also revealed that its synthesis can regulate cellular functions via the reprogramming of cellular metabolism. This review highlights the current advances in knowledge on the biosynthesis and catabolism of hyaluronan and describes the diverse functions associated with hyaluronan metabolism.

Croton urucurana Baillon stem bark ointment accelerates the closure of cutaneous wounds in knockout IL-10 mice

ETHNOPHARMACOLOGICAL RELEVANCE

Croton urucurana Baill. (Euphorbiaceae) is a plant used in Brazilian popular medicine for the treatment of wound healing, inflammatory diseases, gastritis, infections, and hemorrhoids.

AIM

The present study aimed to evaluate the in vivo wound healing activity of an ointment based on ethanolic extract of C. urucurana stem bark, at concentrations of 5% and 10%, and to relate it with compounds that could be associated with this activity.

MATERIALS AND METHODS

Analyses by FIA-ESI-IT-MSⁿ were carried out to investigate the chemical composition of C. urucurana. Knockout IL-10 (n = 60) mice and wild type C57 (n = 12) mice were separated into 6 groups to evaluate the wound healing activity. Knockout IL-10 mice: SAL (0.9% saline); BAS (ointment base); SS (1% silver sulfadiazine); CR1 (ointment with extract of C. urucurana 5%); CR2 (ointment with extract of C. urucurana 10%); and wild mice C57: SALC57 (Saline 0.9%). A circular wound with 10 mm in diameter was generated on the dorsal of the animals. Tissue specimen of the wounds were removed on days 7 and 14 of the treatment for histopathological, oxidative status and analyses of pro-and anti-inflammatory cytokines in scar tissue.

RESULTS

In the phytochemical profile, twelve proanthocyanidins were identified (in the form of monomers, dimers, trimers, and tetramers), based on (epi)catechin and (epi)gallocatechin. Furthermore, two quercetin derivatives and two alkaloids were detected. The groups treated with CR1 and CR2 ointments presented higher rate of wound closure, increased total number of cells, mast cells, blood vessels and higher deposition of type III and I collagen. In addition, they showed increased amount of pro-inflammatory cytokines (IL- 2 and IFN-γ), and anti-inflmatory cytokines (IL-4), on the 7th day of treatment.

CONCLUSION

The results presented support the popular use of preparations based on the bark of C. urucurana as a healing compound.

Mechanisms of ivermectin-induced wound healing

BACKGROUND

Wounds cause structural and functional discontinuity of an organ. Wound healing, therefore, seeks to re-establish the normal morphology and functionality through intertwined stages of hemostasis, inflammation, proliferation, and tissue remodelling. Ivermectin, a macrolide, has been used as an endectoparasiticide in human and veterinary medicine practice for decades. Here, we show that ivermectin exhibits wounding healing activity by mechanisms independent of its well-known antiparasitic activity. This study aimed to evaluate the wound healing property of ivermectin cream using histochemistry and enzyme-linked immunosorbent assay techniques.

RESULTS

Non-irritant dose of ivermectin cream (0.03-1%) decreased wound macroscopic indices such as exudation, edge edema, hyperemia, and granulation tissue deposition by day 9 compared to day 13 for the vehicle-treated group. This corresponded with a statistically significant wound contraction rate, hydroxyproline deposition, and a decreased time to heal rate. The levels of growth factors TGF-β1 and VEGF were significantly elevated on day 7 but decreased on day 21. This corresponded with changes in cytokines (IL-1α, IL-4, IL-10, and TNF-α) and eicosanoids (LTB4, PGE2, and PGD2) levels on days 7 and 21.. Interestingly, low doses of ivermectin cream (0.03-0.1%) induced wound healing with minimal scarring compared to higher doses of the cream and the positive control, Silver Sulfadiazine.

CONCLUSION

Ivermectin promotes wound healing partly through modulation of the inflammatory process and the levels of Transforming Growth Factor-Beta 1 and Vascular Endothelial Growth Factor. Low doses of ivermectin cream have the potential to be used in treating wounds with minimal scar tissue formation.

Bafilomycin A1 Accelerates Chronic Refractory Wound Healing in db/db Mice

Numerous studies have reported that autophagy plays an important role in chronic wound healing, and enhancement of autophagic activity impairs cutaneous wound healing. The autophagy inhibitor Bafilomycin A1 (Baf A1) inhibits autophagy by preventing the formation of autophagosomes. This study aimed at elucidating the effect of Bafilomycin A1 on chronic refractory wound healing in diabetic mice. A total of 40 diabetic (db/db) mice and 20 nondiabetic (db/m) mice were used in this study. Full-thickness skin defects were generated in the db/db mice models, which were then divided into the following two groups: the nontreated (db/db group) and Baf A1-treated groups (Baf A1 group). The same skin defects were generated in db/m mice (db/m group) to serve as a control. We demonstrated that Baf A1 treatment significantly accelerated wound healing in db/db mice and exerted good healing effects. Moreover, Baf A1 inhibited autophagy in the newly generated epidermis and had minor effects on metabolism in db/db mice. PCNA expression, as detected by immunohistochemistry, and collagen thickness, as detected by Masson's trichrome staining on the 14th day, were higher in the db/m and Baf A1 groups than in the db/db group. In addition, the expression of the proinflammatory cytokine TNF-α in the db/m and Baf A1 groups increased significantly on day 6, and the expression of the anti-inflammatory cytokine IL-10 also increased significantly on day 9. However, there were no significant changes in the expression levels of TNF-α and IL-10 in the db/db group. Therefore, Baf A1 may accelerate diabetic chronic refractory wound healing by promoting cell proliferation, collagen production, and regulating the inflammatory balance.

Intrastromal Injection of Hyaluronidase Alters the Structural and Biomechanical Properties of the Corneal Stroma

Purpose

Glycosaminoglycans (GAGs) are important components of the corneal stroma, and their spatiotemporal arrangement regulates the organization of collagen fibrils and maintains corneal transparency. This study was undertaken to determine the consequences of hyaluronidase (HAse) injected into the corneal stroma on stromal stiffness and ultrastructure.

Methods

Equal volumes of HAse or balanced salt solution (vehicle) were injected intrastromally into the corneas of New Zealand white rabbits. Ophthalmic examination and multimodal imaging techniques, including Fourier-domain optical coherence tomography and in vivo confocal microscopy (IVCM), were performed at multiple time points to evaluate the impact of HAse treatment in vivo. Atomic force microscopy and transmission electron microscopy (TEM) were used to measure corneal stiffness and collagen's interfibrillar spacing, respectively.

Results

Central corneal thickness progressively decreased after HAse injection, reaching its lowest value at day 7, and then returned to normal by day 42. The HAse did not impact the corneal endothelium but transiently altered keratocyte morphology at days 1 and 7, as measured by IVCM. HAse-injected corneas became stiffer by day 1 postinjection, were stiffest at day 7, and returned to preinjection values by day 90. Changes in stromal stiffness correlated with decreased interfibrillar spacing as measured by TEM.

Conclusions

Degradation of GAGs by HAse decreases the corneal thickness and increases stromal stiffness through increased packing of the collagen fibrils in a time-dependent manner.

Translational Relevance

Intrastromal HAse injection appears relatively safe in the normal cornea, but its impact on corneal biomechanics and structure under pathologic conditions requires further study.

Experimental models and methods for cutaneous wound healing assessment

Wound healing studies are intricate, mainly because of the multifaceted nature of the wound environment and the complexity of the healing process, which integrates a variety of cells and repair phases, including inflammation, proliferation, reepithelialization and remodelling. There are a variety of possible preclinical models, such as in mice, rabbits and pigs, which can be used to mimic acute or impaired for example, diabetic and nutrition-related wounds. These can be induced by many different techniques, with excision or incision being the most common. After determining a suitable model for a study, investigators need to select appropriate and reproducible methods that will allow the monitoring of the wound progression over time. The assessment can be performed by non-invasive protocols such as wound tracing, photographic documentation (including image analysis), biophysical techniques and/or by invasive protocols that will require wound biopsies. In this article, we provide an overview of some of the most often needed and used: (a) preclinical/animal models including incisional, excisional, burn and impaired wounds; (b) methods to evaluate the healing progression such as wound healing rate, wound analysis by image, biophysical assessment, histopathological, immunological and biochemical assays. The aim is to help researchers during the design and execution of their wound healing studies.

Late hyaluronidase injection in local anesthesia: Morphofunctional evaluation in rat sciatic nerve block

Introduction

Despite the enhancing effects of hyaluronidase (HYAL) over duration of anesthesia, this enzyme could cause adverse effects when injected concomitantly with local anesthetics in dental blocks.

Objective

This study aimed to assess the tissue alterations caused by a local anesthetic protocol consisting of a late HYAL injection and confirm its functional effectiveness.

Materials and Methods

The protocol efficacy was proved by evaluating sensory and motor functions in rats. The sciatic nerve was blocked with 2% lidocaine (LID) with epinephrine (n = 25). Thirty minutes later, 75 TRU/ml HYAL was injected into the same site (experimental group, LID/HYAL). One week later, this protocol was repeated in the contralateral hindlimb, injecting only HYAL's vehicle (control group, LID/vehicle [LID/V]). To observe the integrity of the local tissues, histological specimens were obtained 1, 24, 48, and 72 h after treatment with LID/HYAL or LID/V (n = 16 each) and stained with hematoxylin/eosin and picrosirius red.

Results

Local inflammation was similar in both groups. The integrity of the nerve fibers was preserved, in spite of some inflammation-associated injuries in the surrounding tissues. The reversible tissue disorganization caused by HYAL, probably facilitated the diffusion of the residual anesthetic to the nerve, resulting in a prolonged anesthetic effect (P < 0.05).

Conclusions

No irreversible morphological alterations are caused by the administration of HYAL prior the end of the LID-induced block. Moreover, this protocol prolongs LID's anesthetic effect.

Clinical Applications of Hyaluronidase

Hyaluronidases are enzymes that degrade hyaluronic acid, which constitutes an essential part of the extracellular matrix. Initially discovered in bacteria, hyaluronidases are known to be widely distributed in nature and have been found in many classes including insects, snakes, fish and mammals. In the human, six different hyaluronidases, HYAL1-4, HYAL-P1 and PH-20, have been identified. PH-20 exerts the strongest biologic activity, is found in high concentrations in the testicles and can be localized on the head and the acrosome of human spermatozoa. Today, animal-derived bovine or ovine testicular hyaluronidases as well as synthetic hyaluronidases are clinically applied as adjuncts to increase the bioavailability of drugs, for the therapy of extravasations, or for the management of complications associated with the aesthetic injection of hyaluronic acid-based fillers. Further applications in the fields of surgery, aesthetic medicine, immunology, oncology, and many others can be expected for years to come. Here, we give an overview over the molecular and cellular mode of action of hyaluronidase and the hyaluronic acid metabolism, as well as over current and potential future clinical applications of hyaluronidase.

Development, characterization and pre-clinical trials of an innovative wound healing dressing based on propolis (EPP-AF®)-containing self-microemulsifying formulation incorporated in biocellulose membranes

The considerable role of pristine bacterial cellulose membranes (BC) as ideal dressings have been widely demonstrated to treat wounds and burns. Nevertheless, drawbacks regarding antimicrobial spectrum and frequent dressing replacement are still present. Based on this, the present work proposes an innovative dressing by incorporating a technological self-microemulsifying formulation (SMEF) encapsulating propolis (BC/PP). BC/PP was fully chemically and biologically characterized employing in vitro and in vivo models. Antimicrobial studies demonstrated BC/PP high efficiency against both gran-negative and gran-positive bacteria. Release studies evidenced propolis markers sustained release for up to 7 days. In vivo wound healing activity was assessed by wound healing rate, anti-inflammatory and tissue formation events and the results evidenced the pro-inflammatory activity of BC/PP, which could promote improved healing results. To conclude, BC/PP presented an outstanding antibacterial activity in vitro with weekly replacement and promotion of healing, offering, for the first time, a broad-spectrum biomembrane potential to treat infected wounds.

CD44-dependent inflammation, fibrogenesis, and collagenolysis regulates extracellular matrix remodeling and tensile strength during cutaneous wound healing

Cutaneous wound healing consists of three main phases: inflammation, re-epithelialization, and tissue remodeling. During normal wound healing, these processes are tightly regulated to allow restoration of skin function and biomechanics. In many instances, healing leads to an excess accumulation of fibrillar collagen (the principal protein found in the extracellular matrix - ECM), and the formation of scar tissue, which has compromised biomechanics, tested using ramp to failure tests, compared to normal skin (Corr and Hart, 2013 [1]). Alterations in collagen accumulation and architecture have been attributed to the reduced tensile strength found in scar tissue (Brenda et al., 1999; Eleswarapu et al., 2011). Defining mechanisms that govern cellular functionality and ECM remodeling are vital to understanding normal versus pathological healing and developing approaches to prevent scarring. CD44 is a cell surface adhesion receptor expressed on nearly all cell types present in dermis. Although CD44 has been implicated in an array of inflammatory and fibrotic processes such as leukocyte recruitment, T-cell extravasation, and hyaluronic acid (the principal glycosaminoglycan found in the ECM) metabolism, the role of CD44 in cutaneous wound healing and scarring remains unknown. We demonstrate that in an excisional biopsy punch wound healing model, CD44-null mice have increased inflammatory and reduced fibrogenic responses during early phases of wound healing. At wound closure, CD44-null mice exhibit reduced collagen degradation leading to increased accumulation of fibrillar collagen, which persists after wound closure leading to reduced tensile strength resulting in a more severe scarring phenotype compared to WT mice. These data indicate that CD44 plays a previously unknown role in fibrillar collagen accumulation and wound healing during the injury response.

Ointment vehicles regulate the wound-healing process by modifying the hyaluronan-rich matrix

Topical ointment consists of an active ingredient and vehicle, and the vehicle largely comprises the volume of the ointment. During the treatment of chronic wounds, such as pressure ulcers, the vehicle has been considered inactive, only serving as a carrier of the main pharmaceutical. However, recent reports have indicated that the vehicle has distinct clinical effects that depend on its physicochemical properties. Therefore, an understanding of the action mechanism of the ointment vehicle in wound tissue is necessary. In this study, we established a mouse model to analyze tissue reactions induced by the following ointment vehicles, an oil-in-water emulsion (EM) vehicle; a macrogol ointment (MO), which is a water-soluble, hydrophilic vehicle; and a MOs containing sucrose (MS). EM-treated wounds exhibited an inflammatory reaction characterized by tissue edema and thick granulation tissue; however, MO- and MS-treated wounds did not exhibit this reaction. Moreover, EM-treated wounds exhibited infiltration of inflammatory cells unlike MO-treated wounds. In contrast, the formation of collagenous tissue was dominantly observed in MO-treated wounds. Because the vehicle regulates the water environment of the wound, the water-holding extracellular matrix molecules, including hyaluronan (HA) and proteoglycan, were examined using immunohistochemical and biochemical methods. The versican G1 fragment, serum-derived HA-associated protein (SHAP) and HA (the VG1F-SHAP-HA) complex characteristically found in inflammatory conditions of pressure ulcers was found in EM-treated wounds. To histologically analyze the mechanism of action of the vehicle, we evaluated the ointment vehicle-wound tissue interface in an en bloc manner. Formation of the HA-containing complex was observed locally between the vehicle and wound surface. On the basis of these data, ointment vehicles regulate the wound-healing process through the formation of HA-rich extracellular matrices at the ointment-wound interface. This study provides a better understanding of the treatment of deep-pressure ulcers with focus on ointment vehicles.

Tannic Acid Cross-linked Polysaccharide-Based Multifunctional Hemostatic Microparticles for the Regulation of Rapid Wound Healing

Hemostatic microparticles (HMs) have been widely used in surgery. To improve the comprehensive performance of HMs, multifunctional HMs named HM₁₅ and HM₁₅ ' are prepared from starch, carboxymethyl chitosan, hyaluronic acid, and tannic acid. Herein, tannic acid is used as an effective cross-linker. A 3D network structure for cell growth and wound repair can be formed by secondary cross-linking. Through synergistic effect of these natural materials, the process of wound healing can be regulated controllably. HM₁₅ and HM₁₅ ' have the ability of rapid hemostasis. Moreover, HM₁₅ ' shows excellent properties in antibacteria and wound healing acceleration. Blood clotting time treated with different HMs is shortened obviously from 436.8 s to 126 s. Compared with Celox, HM₁₅ and HM₁₅ ' exhibited better broad spectrum antibacterial activity against both Escherichia coli and Staphylococcus aureus. Notably, the wound can be repaired rapidly by HM₁₅ ' in 14 days. These multifunctional HMs might have an important prospect in clinical application.

Treatment of limb wounds of horses with orf virus IL-10 and VEGF-E accelerates resolution of exuberant granulation tissue, but does not prevent its development

Bandaging of limb wounds in horses leads to formation of exuberant granulation tissue (EGT) that retards healing due to protracted inflammation, aberrant vascularisation and delayed epithelialisation. EGT is not observed if wounds are left undressed or when wounds are on the body. A previous study showed that short-term administration of proteins derived from orf virus dampened inflammation and promoted epithelialisation of open wounds in horses. Here, we investigated the impact of orf virus interleukin-10 and vascular endothelial growth factor-E on the development and resolution of EGT. Excisional wounds were created on the forelimb of four horses, and bandages were maintained until full healing to induce EGT formation. Matching body wounds were created to ensure EGT was limited to the limb, and to differentiate the effects of the viral proteins on normal healing and on EGT formation. Viral proteins or the hydrogel vehicle control were administered topically to site-matched wounds at day 1, with repeat administration at day 8. Wound healing and EGT formation were monitored macroscopically. Wound margin samples were harvested at 2, 7 and 14 days, and at full healing, with histology used to observe epithelialisation, immunofluorescence used to detect inflammatory cells, angiogenesis and cell death, and qPCR to measure expression of genes regulating inflammation and angiogenesis. Limb wounds developed EGT, and exhibited slower healing than body wounds. Viral protein treatment did not accelerate healing at either location nor limit EGT formation in limb wounds. Treatment of limb wounds did however increase epithelialisation and angiogenesis, without dampening inflammatory cell infiltration or gene expression. The healed wounds also had less occlusion and death of blood vessels and fewer epidermal rete ridges following viral protein treatment. These findings indicate that the viral protein treatment does not suppress wound inflammation or EGT formation, but does promote vascular and epidermal repair and EGT resolution.

Shengfu Oil Enhances the Healing of Full-Thickness Scalded Skin Accompanying the Differential Regulation of β-Catenin, Dlk1, and COX-2

Shengfu oil is a traditional Chinese medicine formula containing 16 ingredients, including Scutellariae radix, Olibanum, and Rehmanniae radix. In this study, we aimed to enhance the wound healing of rabbit full-thickness scalded skin by Shengfu oil and to elucidate its regulatory effects on β-catenin, Dlk1, and COX-2. We found that Shengfu oil exhibited significant anti-inflammatory, analgesic, and antimicrobial activities. The structure of wound tissues in Shengfu oil group was intact, including regenerated cutaneous appendages, indicating better healing capability of Shengfu oil compared to the controls. The protein expression of β-catenin, Dlk1, and COX-2 in wound tissues were investigated by immunohistochemistry staining and were further quantitated with the use of multispectral imaging analysis. The protein expression of β-catenin and Dlk1 in the Shengfu oil group was higher than that in the sesame oil group in early wound repair, accompanied by the lower expression of COX-2; the protein expression of β-catenin decreased in the middle of wound healing; the protein expression of β-catenin and Dlk1 increased at the end of wound healing. These results strongly suggest that Shengfu oil can enhance wound healing by regulating the expression of β-catenin, Dlk1, and COX-2 due to its excellent anti-inflammatory, analgesic, and antimicrobial activities.

Treatment of a burn animal model with functionalized tridimensional electrospun biomaterials

Laminin-functionalized poly-d,l-lactic acid scaffolds were produced. Following this, mesenchymal stem cells and keratinocytes were seeded on biomaterials for the in vivo experiments, where the biomaterials with or without cells were implanted. The analysis is comprised of the visual aspect and mean size of the lesion plus the histology and gene expression. The results showed that the cells occupied all the structure of the scaffolds in all the groups. After nine days of in vivo experiments, the defect size did not show statistical difference among the groups, although the groups with the poly-d,l-lactic acid/Lam biomaterial had the lowest lesion size and presented the best visual aspect of the wound. Gene expression analysis showed considerable increase of tumor growth factor beta 1 expression, increased vascular endothelial growth factor and balance of the BAX/Bcl-2 ratio when compared to the lesion group. Histological analysis showed well-formed tissue in the groups where the biomaterials and biomaterials plus cells were used. In some animals, in which biomaterials and cells were used, the epidermis was formed throughout the length of the wound. In conclusion, these biomaterials were found to be capable of providing support for the growth of cells and stimulated the healing of the skin, which was improved by the use of cells.

Lipoxin A4 encapsulated in PLGA microparticles accelerates wound healing of skin ulcers

Lipoxin A₄ (LXA₄) is involved in the resolution of inflammation and wound healing; however, it is extremely unstable. Thus, to preserve its biological activities and confer stability, we encapsulated LXA₄ in poly-lactic-co-glycolic acid (PLGA) microparticles (LXA₄-MS) and assessed its application in treating dorsal rat skin lesions. Ulcers were sealed with fibrin adhesive and treated with either LXA₄-MS, unloaded microparticles (Un-MS), soluble LXA₄, or PBS/glue (vehicle). All groups were compared at 0, 2, 7, and 14 days post-lesions. Our results revealed that LXA₄-MS accelerated wound healing from day 7 and reduced initial ulcer diameters by 80%. Soluble LXA₄, Un-MS, or PBS closed wounds by 60%, 45%, and 39%, respectively. LXA₄-MS reduced IL-1β and TNF-α, but increased TGF-β, collagen deposition, and the number of blood vessels. Compared to other treatments, LXA₄-MS reduced inflammatory cell numbers, myeloperoxidase (MPO) concentration, and metalloproteinase-8 (MMP8) mRNA in scar tissue, indicating decreased neutrophil chemotaxis. In addition, LXA₄-MS treatment increased macrophages and IL-4, suggesting a positive impact on wound healing. Finally, we demonstrated that WRW4, a selective LXA₄ receptor (ALX) antagonist, reversed healing by 50%, indicating that LXA₄ must interact with ALX to induce wound healing. Our results show that LXA₄-MS could be used as a pharmaceutical formulation for the treatment of skin ulcers.

The role of histamine in the regulation of the viability, proliferation and transforming growth factor β1 secretion of rat wound fibroblasts

BACKGROUND

Inflammation mediators play a regulatory role in repair processes. The study will examine the influence of histamine on wound fibroblast metabolic activity, viability, proliferation, and TGFβ1 secretion. The study also will identify the histamine receptor involved in regulation of the tested repair processes.

METHODS

Fibroblasts were obtained from the granulation tissue of wounds or intact dermis of rats. The MTT and BrdU assays were used to examine the effect of histamine (10^-8M-10^-4M) on the viability and metabolic activity of fibroblasts, and on their proliferative capacity. The influence of histamine receptor antagonists (i.e., ketotifen, ranitidine, ciproxifan and JNJ7777120) and agonists (2-pyridylethlamine dihydrochloride, amthamine dihydrobromide) was also investigated. The TGFβ1 and histamine receptors H1 were evaluated by enzyme-linked immunosorbent assay.

RESULTS

Histamine significantly increased granulation tissue fibroblast viability and metabolic activity at 10^-8 and 10^-6M but did not change their proliferative activity. Only the blockade of the H1 receptor removed this effect of histamine. H1 receptor agonist (2-pyridylethlamine dihydrochloride) increased cell viability, thereby mimicking histamine action. Both Histamine (10^-4M) and 2-pyridylethlamine dihydrochloride increased TGFβ1 concentration in cell culture medium. However, ketotifen blocked histamine-induced augmentation of TGFβ1. H1 receptor expression on wound fibroblasts was confirmed.

CONCLUSION

The regulatory influence of histamine on wound fibroblast function (viability/metabolic activity or secretion of TGFβ1) is dependent on H1 receptor stimulation. Contrary to wound fibroblasts, these cells express a very low level of H1 receptors when isolated from intact dermis and histamine is unable to modify their metabolic activity.

Comparison of collagen content in skin wounds evaluated by biochemical assay and by computer-aided histomorphometric analysis

CONTEXT

The quantification of total collagen is of major importance in a wide range of research areas, including the study of cutaneous wound healing and new drugs trials.

OBJECTIVE

The total collagen content in skin biopsies was compared by biochemical hydroxyproline assay and by two computer-aided histomorphometric analyses of histological sections.

MATERIALS AND METHODS

Two methods were used to evaluate collagen formation: the hydroxyproline assay, as the gold standard and histomorphometric image analysis of the filled areas by corresponding stained collagen fibres, using picrosirius and Gomori's trichrome staining. The image analyses were determined by digital densitometry recognition using computer-aided ImageJ software. One-way ANOVA, simple linear regression and ANCOVA were applied for the statistical analysis and correlation.

RESULTS

In a simple linear regression analysis carried out on the 14th day period after the induction of skin injury, three techniques, picrosirius red (F = 33.57, p = 0.00), Gomori's trichrome (F = 81.61, p = 0.00) and hydroxyproline content (F = 16.85, p = 0.00) were able to detect collagen production. After scale adjustment, there were no significant differences among either the slopes (F = 1.17, p = 0.32) or the intercepts (F = 0.69, p = 0.51) of the estimated regression lines. It seems that a highly significant correlation exists between the histomorphometrical analysis and hydroxyproline assay.

DISCUSSION AND CONCLUSION

The morphometric analysis proved to be adequate and can be used as a simple, rapid, low-cost technology for evaluating total collagen in cutaneous wound specimens, compared with the gold standard hydroxyproline assay.

Viability of randomized skin flaps-an experimental study in rats

BACKGROUND

Randomized skin flaps are extensively used in plastic surgery, but the possibility of necrosis has challenged their use. Several studies have been conducted aiming to find ways to reduce the occurrence of necrosis. We evaluated the effects of pentoxifylline (PTX) and hyaluronidase (HLD), each alone or combined, on randomized rat skin flaps.

MATERIALS AND METHODS

Fifty male Wistar rats were divided into five groups of 10 animals each: control I, control II, PTX, HLD, PTX-HLD. Substances were administered from the first to the 14th postoperative day. The necrotic area was measured on the seventh and 14th postoperative day; the animals were killed on the 14th day, when samples were collected for histologic and immunohistochemical examination.

RESULTS

On the seventh day, percentage of the necrotic area was significantly reduced in PTX, HLD, and PTX-HLD animals compared with control groups. On 14th day, percentage of the necrotic area in PTX, HDL, and PTX-HLD groups was also significantly reduced compared with control groups. PTX and PTX-HLD showed a significant reduction in dermis cellularity, V_V of macrophages, and myofibroblasts compared with control groups; PTX showed a significant enhancement of L_V of blood vessels compared with all other groups.

CONCLUSIONS

The use of each substance alone or combined increased flap viability compared with control groups. On the seventh day, PTX exhibited lower viability than HLD, whereas on the 14th day there was no difference between treated groups. PTX alone enhanced the L_V of blood vessels, whereas PTX-HLD did not. However, PTX-HLD was more effective in decreasing the dermis cellularity and macrophage V_V than HLD alone.

Struthanthus vulgaris ointment prevents an over expression of inflammatory response and accelerates the cutaneous wound healing

ETHNOPHARMACOLOGICAL RELEVANCE

Struthanthus vulgaris (Vell.) Mart. (Loranthaceae) has been largely used in traditional folk medicine in Brazil as an anti-inflammatory agent and to treat various skin disorders, including wounds.

AIMS OF THE STUDY

To investigated the influence of 5% Struthanthus vulgaris ointment during cutaneous wound healing in rats.

MATERIALS AND METHODS

Twenty Wistar rats were used in each group according the daily treatment, S. vulgaris 5% ointment (SV 5%) and vehicle control groups. Four full thicknesses wounds were punched in back side skin of each animal, and five animals were sacrificed after 2, 7, 14 and 21 days after surgery for histological, immunological and biochemical analysis.

RESULTS

A significant wound closured area in the S. vulgaris 5% group of about 38% and 35% as compared to 19% and 21% in the control group was observed after 2 and 5 days, respectively. Histological and biochemical analysis of the skin biopsies showed that S. vulgaris treated wounds exhibited increased granulation tissue and regulated the inflammatory response by modulating the release of pro and anti-inflammatory cytokines like IL-1α, TNF-α and IL-10, nitric oxide and, growth factors like TGF-β. Moreover, S. vulgaris showed a marked and robust increase in the deposition and organization of collagen fibers in the wounds, and improve the quality of the scar tissue.

CONCLUSIONS

Altogether these data revealed that S. vulgaris seems to prevent an over expression of inflammation and accelerates wound epithelialization and might be beneficial for treating healing disorders.

Arthropod venom Hyaluronidases: biochemical properties and potential applications in medicine and biotechnology

Hyaluronidases are enzymes that mainly degrade hyaluronan, the major glycosaminoglycan of the interstitial matrix. They are involved in several pathological and physiological activities including fertilization, wound healing, embryogenesis, angiogenesis, diffusion of toxins and drugs, metastasis, pneumonia, sepsis, bacteremia, meningitis, inflammation and allergy, among others. Hyaluronidases are widely distributed in nature and the enzymes from mammalian spermatozoa, lysosomes and animal venoms belong to the subclass EC 3.2.1.35. To date, only five three-dimensional structures for arthropod venom hyaluronidases (Apis mellifera and Vespula vulgaris) were determined. Additionally, there are four molecular models for hyaluronidases from Mesobuthus martensii, Polybia paulista and Tityus serrulatus venoms. These enzymes are employed as adjuvants to increase the absorption and dispersion of other drugs and have been used in various off-label clinical conditions to reduce tissue edema. Moreover, a PEGylated form of a recombinant human hyaluronidase is currently under clinical trials for the treatment of metastatic pancreatic cancer. This review focuses on the arthropod venom hyaluronidases and provides an overview of their biochemical properties, role in the envenoming, structure/activity relationship, and potential medical and biotechnological applications.

Alginate-hyaluronan composite hydrogels accelerate wound healing process

In this paper we propose polysaccharide hydrogels combining alginate (ALG) and hyaluronan (HA) as biofunctional platform for dermal wound repair. Hydrogels produced by internal gelation were homogeneous and easy to handle. Rheological evaluation of gelation kinetics of ALG/HA mixtures at different ratios allowed understanding the HA effect on ALG cross-linking process. Disk-shaped hydrogels, at different ALG/HA ratio, were characterized for morphology, homogeneity and mechanical properties. Results suggest that, although the presence of HA does significantly slow down gelation kinetics, the concentration of cross-links reached at the end of gelation is scarcely affected. The in vitro activity of ALG/HA dressings was tested on adipose derived multipotent adult stem cells (Ad-MSC) and an immortalized keratinocyte cell line (HaCaT). Hydrogels did not interfere with cell viability in both cells lines, but significantly promoted gap closure in a scratch assay at early (1 day) and late (5 days) stages as compared to hydrogels made of ALG alone (p<0.01 and 0.001 for Ad-MSC and HaCaT, respectively). In vivo wound healing studies, conducted on a rat model of excised wound indicated that after 5 days ALG/HA hydrogels significantly promoted wound closure as compared to ALG ones (p<0.001). Overall results demonstrate that the integration of HA in a physically cross-linked ALG hydrogel can be a versatile strategy to promote wound healing that can be easily translated in a clinical setting.

The Choice of Enzyme for Human Pancreas Digestion is a Critical Factor for Increasing the Success of Islet Isolation

BACKGROUND

We evaluated three commercially available enzymes for pancreatic digestion by comparing key parameters during the islet isolation process, as well as islet quality post-isolation.

METHODS

Retrospectively compared and analyzed islet isolations from pancreata using three different enzyme groups: Liberase HI (n=63), Collagenase NB1/Neutral Protease (NP) (n=43), and Liberase Mammalian Tissue Free Collagenase/Thermolysin (MTF C/T) (n=115). A standardized islet isolation and purification method was used. Islet quality assessment was carried out using islet count, viability, in vitro glucose-stimulated insulin secretion (GSIS), glucose-stimulated oxygen consumption rate (ΔOCR), and in vivo transplantation model in mice.

RESULTS

Donor characteristics were not significantly different among the three enzyme groups used in terms of age, sex, hospital stay duration, cause of death, body mass index (BMI), hemoglobin A1c (HbA1c), cold ischemia time (CIT), and pancreas weight. Digestion efficacy (percentage of digested tissue by weight) was significantly higher in the Liberase MTF C/T group (73.5 ± 1.5 %) when compared to the Liberase HI group (63.6 ± 2.3 %) (p<0.001) and the Collagenase NB1/NP group (61.7 ± 2.9%) (p<0.001). The stimulation index for GSIS was significantly higher in the Liberase MTF C/T group (5.3 ± 0.5) as compared to the Liberase HI (2.9 ± 0.2) (p<0.0001) and the Collagenase NB1/NP (3.6 ± 2.9) (p=0.012) groups. Furthermore, the Liberase MTF C/T enzymes showed the highest success rate of transplantation in diabetic NOD Scid mice (65%), which was significantly higher than the Liberase HI (42%, p=0.001) and the Collagenase NB1/NP enzymes (41%, p<0.001).

CONCLUSIONS

Liberase MTF C/T is superior to Liberase HI and Collagenase NB1/NP in terms of digestion efficacy and glucose-stimulated insulin secretion in vitro. Moreover, Liberase MTF C/T had a significantly higher success rate of transplantation in diabetic NOD Scid mice compared to Liberase HI and Collagenase NB1/NP enzymes.