The accelerating effect of histamine on the cutaneous wound-healing process through the action of basic fibroblast growth factor

Bioactive nanomaterials kickstart early repair processes and potentiate temporally modulated healing of healthy and diabetic wounds

Slow-healing and chronic wounds represent a major global economic and medical burden, and there is significant unmet need for novel therapies which act to both accelerate wound closure and enhance biomechanical recovery of the skin. Here, we report a new approach in which bioactives that augment early stages of wound healing can kickstart and engender effective wound closure in healthy and diabetic, obese animals, and set the stage for subsequent tissue repair processes. We demonstrate that a nanomaterial dressing made of silk fibroin and gold nanorods (GNR) stimulates a pro-neutrophilic, innate immune, and controlled inflammatory wound transcriptomic response. Further, Silk-GNR, lasered into the wound bed, in combination with exogeneous histamine, accelerates early-stage processes in tissue repair leading to effective wound closure. Silk-GNR and histamine enhanced biomechanical recovery of skin, increased transient neoangiogenesis, myofibroblast activation, epithelial-to-mesenchymal transition (EMT) of keratinocytes and a pro-resolving neutrophilic immune response, which are hitherto unknown activities for these bioactives. Predictive and temporally coordinated delivery of growth factor nanoparticles that modulate later stages of tissue repair further accelerated wound closure in healthy and diabetic, obese animals. Our approach of kickstarting healing by delivering the "right bioactive at the right time" stimulates a multifactorial, pro-reparative response by augmenting endogenous healing and immunoregulatory mechanisms and highlights new targets to promote tissue repair.

A novel multifunctional chitosan-gelatin/carboxymethyl cellulose-alginate bilayer hydrogel containing human placenta extract for accelerating full-thickness wound healing

The replication of skin's dermal and epidermal morphology within a full-thickness wound using a bi-layer hydrogel to cater to their distinct needs is a compelling pursuit. Moreover, human placenta extract (HPE), containing a diverse array of bioactive agents, has proven to be effective in promoting the wound healing process and enhancing epidermal keratinocytes. This study presents a multifunctional bi-layer hydrogel incorporating HPE for accelerating full-thickness wound healing through sustained HPE release, inhibition of bacteria invasion, and promotion of cell proliferation. The upper layer of the scaffold, known as the dressing layer, is composed of carboxymethyl cellulose and sodium alginate, serving as a supportive layer for cell proliferation. The under layer, referred to as the regenerative layer, is composed of chitosan and gelatin, providing an extracellular matrix-like, porous, moist, and antibacterial environment for cell growth. The scaffold was optimized to replicate the morphology of the dermal and epidermal layers, with suitable fibroblast infiltration and a pore size of approximately 283μm. Furthermore, the degradation rate of the samples matched the wound healing rate and persisted throughout this period. The sustained HPE release rate, facilitated by the degradation rate, was optimized to reach ~98% after 28 days, covering the entire healing period. The samples demonstrated robust antibacterial capabilities, with bacterial inhibition zone diameters of and 2.63±0.12cm for S. aureus and E. coli, respectively. The biocompatibility of the samples remained at approximately 68.33±4.5% after 21 days of fibroblast cell culture. The in vivo experiment indicated that the HPE@Bilayer hydrogel promotes the formation of new blood vessels and fibroblasts during the early stages of healing, leading to the appropriate formation of granulation tissue and a wound contraction rate of (79.31±3.1)%. Additionally, it resulted in the formation of a thick epidermal layer (keratinization) that effectively covered all the impaired areas, achieving a wound contraction rate of 95.83±6.3% at the late stage of wound healing. Furthermore, immunohistochemistry staining for CD31 and TGF-β revealed that the HPE@Bilayer group had 22 blood vessels/field and 34%-66% immunoactive cells, respectively, after 14 days of healing. However, by day 21, angiogenesis and TGF-β expression had declined, demonstrating that the wounds had been successfully treated with minimal scarring.

Dasatinib Ointment Promotes Healing of Murine Excisional Skin Wound

Dasatinib, a tyrosine kinase inhibitor, has been shown to produce anti-inflammatory activity and impair vascular integrity in vivo, including during skin wound healing, potentially promoting the repair process. Given that dasatinib is a lipophilic small molecule capable of penetrating skin, topical dasatinib might provide benefits in wound healing. In the present study, we investigated the impact of dasatinib ointments in skin wound healing in mice. A full thickness excisional skin wound (4 mm diameter) was generated on the shaved dorsum of eight-week-old C57BL/6 mice. Dasatinib ointment (0.1 or 0.2% w/w) or ointment base was applied twice daily (every 12 h) for 10 days. Elizabethan collars were used to prevent animal licking. The wound size was monitored daily for 14 days. The results showed that dasatinib ointments, particularly 0.1% dasatinib, promoted a 16-23% reduction in wound size (p < 0.05) during day 2 to day 6 postinjury compared to controls. Immunohistochemistry analyses demonstrated a reduction in wound neutrophils (38% reduction, p = 0.04), macrophages (47% reduction, p = 0.005), and tumor necrosis factor-α levels (73% reduction, p < 0.01), together with an induction of vascular leakage-mediated fibrin(ogen) accumulation (2.5-fold increase, p < 0.01) in the wound during day 3 postinjury (an early phase of repair) in 0.1% dasatinib-treated mice relative to control mice. The anti-inflammatory and vascular hyperpermeability activities of dasatinib were associated with an enhanced healing process, including increased keratinocyte proliferation (1.8-fold increase in Ki67+ cells, p < 0.05) and augmented angiogenesis (1.7-fold increase in CD31+ area, p < 0.05), compared to the ointment base-treated group. Following treatment with 0.2% dasatinib ointment, minor wound bleeding and scab reformation were observed during the late phase, which contributed to delayed healing. In conclusion, our data suggest that dasatinib ointment, mainly at 0.1%, promotes the repair process by reducing inflammation and producing a local and temporal vascular leakage, leading to an increase in fibrin(ogen) deposition, re-epithelialization, and angiogenesis. Therefore, topical dasatinib might be a potential novel candidate to facilitate skin wound healing.

Hormesis: wound healing and fibroblasts

Hormetic dose responses are reported here to occur commonly in the dermal wound healing process, with the particular focus on cell viability, proliferation, migration and collagen deposition of human and murine fibroblasts with in vitro studies. Hormetic responses were induced by a wide range of substances, including endogenous agents, pharmaceutical preparations, plant-derived extracts including many well-known dietary supplements, as well as physical stressor agents such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings complement and extend a similar comprehensive assessment concerning the occurrence of hormetic dose responses in keratinocytes. These findings demonstrate the generality of the hormetic dose response for key wound healing endpoints, suggesting that the hormesis concept has a fundamental role in wound healing, with respect to guiding strategies for experimental evaluation as well as therapeutic applications.

Inflammatory Microenvironment of Skin Wounds

Wound healing is a dynamic and highly regulated process that can be separated into three overlapping and interdependent phases: inflammation, proliferation, and remodelling. This review focuses on the inflammation stage, as it is the key stage of wound healing and plays a vital role in the local immune response and determines the progression of wound healing. Inflammatory cells, the main effector cells of the inflammatory response, have been widely studied, but little attention has been paid to the immunomodulatory effects of wound healing in non-inflammatory cells and the extracellular matrix. In this review, we attempt to deepen our understanding of the wound-healing microenvironment in the inflammatory stage by focusing on the interactions between cells and the extracellular matrix, as well as their role in regulating the immune response during the inflammatory stage. We hope our findings will provide new ideas for promoting tissue regeneration through immune regulation.

Burn Wound Healing: Clinical Complications, Medical Care, Treatment, and Dressing Types: The Current State of Knowledge for Clinical Practice

According to the World Health Organization (WHO), it is estimated that each year approximately 11 million people suffer from burn wounds, 180,000 of whom die because of such injuries. Regardless of the factors causing burns, these are complicated wounds that are difficult to heal and are associated with high mortality rates. Medical care of a burn patient requires a lot of commitment, experience, and multidirectional management, including surgical activities and widely understood pharmacological approaches. This paper aims to comprehensively review the current literature concerning burn wounds, including classification of burns, complications, medical care, and pharmacological treatment. We also overviewed the dressings (with an emphasis on the newest innovations in this field) that are currently used in medical practice to heal wounds.

Amnion bilayer for dressing and graft replacement for delayed grafting of full-thickness burns; A study in a rat model

Burn is a common case in developing countries, with over half of fire-related deaths reported in Southeast Asia and full-thickness burns as a high mortality risk. Human amnion has been used as a wound dressing for centuries. In this study, a decellularised amnion overlaid with fibrin, “amnion bilayer (AB),” was used as a dressing immediately after burn and as a graft to replace the scar in Sprague-Dawley rats subjected to full-thickness burn model. The aim was to observe whether amnion bilayer can reduce damages in third-grade burn when skin replacement is deemed impossible. The burn was induced using an electrical solder, heated for 5 mins, and contacted on the rat’s bare skin for 20 s. AB was applied as a (i) dressing immediately after induction and graft after eschar removal. Two groups (n = 6) were compared: AB and Sofra-Tulle ^®, the National Hospital of Indonesia (NHI) protocol. Sections were stained with hematoxylin and eosin and Masson trichrome stains. Immunohistochemistry labelling was used to indicate scars (α-smooth muscle actin [α-SMA] and collagen-1) and angiogenesis (von Willebrand factor). Also, the macrophages inflammatory protein-3α (MIP-3α) indicates an early inflammatory process. The post dressing of the AB group demonstrated hair follicle remains and adipose tissue development. The NHI group appeared with a denatured matrix. Complete healing was seen in the AB group after 28 days with skin appendages similar to normal, while the NHI group showed no appendages in the centre of the actively inflamed area. The α-SMA was found in both groups. Collagen-1 was highly expressed in the NHI group, which led to a scar. Angiogenesis was found more in the AB group. The AB group had shown the capacity to accelerate complete healing and recover skin appendages better than the current protocol.

Growth Factors, Reactive Oxygen Species, and Metformin-Promoters of the Wound Healing Process in Burns?

Burns can be caused by various factors and have an increased risk of infection that can seriously delay the wound healing process. Chronic wounds caused by burns represent a major health problem. Wound healing is a complex process, orchestrated by cytokines, growth factors, prostaglandins, free radicals, clotting factors, and nitric oxide. Growth factors released during this process are involved in cell growth, proliferation, migration, and differentiation. Reactive oxygen species are released in acute and chronic burn injuries and play key roles in healing and regeneration. The main aim of this review is to present the roles of growth factors, reactive oxygen species, and metformin in the healing process of burn injuries.

Improvement of Cutaneous Wound Healing via Topical Application of Heat-Killed Lactococcus chungangensis CAU 1447 on Diabetic Mice

Cutaneous wound healing comprises a complex systemic network. Probiotics, naturally extracted substances, medicine, and chemical compounds have been used for wound healing, but the application of postbiotics as therapeutic agents has yet to be explored. Our study shows potential beneficial effects of heat-killed Lactococcus chungangensis CAU 1447 on type 1 diabetic mice. The postbiotic strain significantly decreased the skin wound size. The activity of myeloperoxidase secreted from neutrophils also decreased. The molecular mechanism of wound healing was adjusted by important mediators, growth factors, chemokines, and cytokines. These elements regulated the anti-inflammatory activity and accelerated wound healing. To determine the role of the postbiotic in wound repair, we showed a similar taxonomic pattern as compared to the diabetic mice using skin microbiome analysis. These findings demonstrated that heat-killed Lactococcus chungangensis CAU 1447 had beneficial effects on wound healing and can be utilized as postbiotic therapeutic agents.

Stable Gastric Pentadecapeptide BPC 157 and Wound Healing

Significance: The antiulcer peptide, stable gastric pentadecapeptide BPC 157 (previously employed in ulcerative colitis and multiple sclerosis trials, no reported toxicity (LD1 not achieved)), is reviewed, focusing on the particular skin wound therapy, incisional/excisional wound, deep burns, diabetic ulcers, and alkali burns, which may be generalized to the other tissues healing.

Recent Advances: BPC 157 has practical applicability (given alone, with the same dose range, and same equipotent routes of application, regardless the injury tested).

Critical Issues: By simultaneously curing cutaneous and other tissue wounds (colocutaneous, gastrocutaneous, esophagocutaneous, duodenocutaneous, vesicovaginal, and rectovaginal) in rats, the potency of BPC 157 is evident. Healing of the wounds is accomplished by resolution of vessel constriction, the primary platelet plug, the fibrin mesh which acts to stabilize the platelet plug, and resolution of the clot. Thereby, BPC 157 is effective in wound healing much like it is effective in counteracting bleeding disorders, produced by amputation, and/or anticoagulants application. Likewise, BPC 157 may prevent and/or attenuate or eliminate, thus, counteract both arterial and venous thrombosis. Then, confronted with obstructed vessels, there is circumvention of the occlusion, which may be the particular action of BPC 157 in ischemia/reperfusion.

Future Directions: BPC 157 rapidly increases various genes expression in rat excision skin wound. This would define the healing in the other tissues, that is, gastrointestinal tract, tendon, ligament, muscle, bone, nerve, spinal cord, cornea (maintained transparency), and blood vessels, seen with BPC 157 therapy.

Potassium bromate (KBrO3) modulates oxidative stress and inflammatory biomarkers in sodium hydroxide (NaOH) - induced Crohn's colitis in Wistar rats

Potassium bromate (KBrO₃) present in consumed ozonised water was recently documented to exacerbate experimental gastric ulcer. Information, however, is vague as regards its effects in the colon where water reabsorption occurs. In this study, we observed the possible effects of KBrO₃ on oxidative stress and inflammatory biomarkers in sodium hydroxide (NaOH) - induced Crohn's colitis (CC). Wistar rats (180-200 g) were divided into six groups (n = 10): (i) control; (ii) untreated CC (induced by 1.4% NaOH; intra-rectal administration); and (iii-vi) CC treated with vitamin E, KBrO₃, vitamin E+KBrO₃, and sulphazalazine, respectively, for 7 days. Body weight and stool score were monitored daily. By day 3 and 7, excised colon was evaluated for ulcer scores and biochemical and histological analysis. Blood samples collected on days 3 and 7 were assayed for haematological indices using standard methods. Data were subjected to analysis of variance (ANOVA) and p ≤ 0.05 considered significant. Platelet/lymphocyte ratio, colonic ulcer score, malondialdehyde, and mast cells were significantly decreased while colonic sulfhydryl, and Ca²⁺- and Na⁺/K⁺-ATPase activities were increased following KBrO₃ treatment compared with untreated CC. These findings suggest that KBrO₃ may mitigate against NaOH-induced CC via inhibiting mast cell population and oxidative and inflammatory content but stimulating colonic sulfhydryl and Ca²⁺- and Na⁺/K⁺-ATPase activities.

Optical Coherence Tomography Angiography Monitors Cutaneous Wound Healing under Angiogenesis-Promoting Treatment in Diabetic and Non-Diabetic Mice

During wound healing, the rapid re-establishment of a functional microcirculation in the wounded tissue is of utmost importance. We applied optical coherence tomography (OCT) angiography to evaluate vascular remodeling in an excisional wound model in the pinnae of C57BL/6 and db/db mice receiving different proangiogenic topical treatments. Analysis of the high-resolution OCT angiograms, including the four quantitative parameters vessel density, vessel length, number of bifurcations, and vessel tortuosity, revealed changes of the microvasculature and allowed identification of the overlapping wound healing phases hemostasis, inflammation, proliferation, and remodeling. Angiograms acquired in the inflammatory phase in the first days showed a dilation of vessels and recruitment of pre-existing capillaries. In the proliferative phase, angiogenesis with the sprouting of new capillaries into the wound tissue led to an increase of the OCT angiography parameters vessel density, normalized vessel length, number of bifurcations, and vessel tortuosity by 28–47%, 39–52%, 33–48%, and 3–8% versus baseline, respectively. After the peak observed on study days four to seven, the parameters slowly decreased but remained still elevated 18 days after wounding, indicating a continuing remodeling phase. Our study suggests that OCT angiography has the potential to serve as a valuable preclinical research tool in studies investigating impaired vascular remodeling during wound healing and potential new treatment strategies.

The immunologic changes during different phases of intestinal anastomotic healing

Intestinal anatomosis is a complex and multicellular process that involving three overlapped phases: exudative phase, proliferative phase, and reparative phase. Undisturbed anastomotic healings are crucial for the recovery of patients after operations but unsuccessful healings are linked with a considerable mortality. This time, we concentrate on the immunologic changes during different phases of intestinal anastomotic healing and select several major immune cells and cytokines of each phase to get a better understanding of these immunologic changes in different phases, which will be significant for more precise therapy strategies in anastomoses.

Biliary damage and liver fibrosis are ameliorated in a novel mouse model lacking l-histidine decarboxylase/histamine signaling

Primary sclerosing cholangitis (PSC) is characterized by biliary damage and fibrosis. Multidrug resistance-2 gene knockout (Mdr2^-/-) mice and PSC patients have increased histamine (HA) levels (synthesized by l-histidine decarboxylase, HDC) and HA receptor (HR) expression. Cholestatic HDC^-/- mice display ameliorated biliary damage and hepatic fibrosis. The current study evaluated the effects of knockout of HDC^-/- in Mdr2^-/- mice (DKO) on biliary damage and hepatic fibrosis. WT, Mdr2^-/- mice, and homozygous DKO mice were used. Selected DKO mice were treated with HA. We evaluated liver damage along with HDC expression and HA serum levels. Changes in ductular reaction were evaluated along with liver fibrosis, inflammation and bile acid signaling pathways. The expression of H1HR/PKC-α/TGF-β1 and H2HR/pERK/VEGF-C was determined. In vitro, cholangiocyte lines were treated with HA with/without H1/H2 inhibitors before measuring: H1/H2HR, TGF-β1, and VEGF-C expression. Knockout of HDC ameliorates hepatic damage, ductular reaction, fibrosis, inflammation, bile acid signaling and H1HR/PKC-α/TGF-β1 and H2HR/pERK/VEGF-C signaling. Reactivation of the HDC/HA axis increased these parameters. In vitro, stimulation with HA increased HR expression and PKC-α, TGF-β1, and VEGF-C expression, which was reduced with HR inhibitors. Our data demonstrate the key role for the HDC/HA axis in the management of PSC progression.

Differential Expression and Function of Bicellular Tight Junctions in Skin and Oral Wound Healing

Bicellular tight junctions are multiprotein complexes that are required for maintenance of barrier function and fence function in epithelial tissues. Wound healing in the oral cavity leads to minimal scar formation compared to the skin, and the precise mechanisms for this regenerative response remain to be elucidated. We hypothesized that oral and skin tissues express a different tight junction repertoire both at baseline and during the wound healing response, and that these molecules may be critical to the differential repair between the two tissues. We re-analyzed a mouse skin and palate epithelium microarray dataset to identify the tight junction repertoire of these tissue types. We then re-analyzed a skin and tongue wound healing microarray dataset to see how expression levels of tight junction genes change over time in response to injury. We performed in vitro scratch assays on human oral and skin keratinocyte cell lines to assay for tight junction expression over time, tight junction expression in response to lipopolysaccharide and histamine treatment, and the effects of siRNA knockdown of claudin 1 or occludin on migration and proliferation. Our data showed that oral and skin epithelium expressed different tight junction genes at baseline and during the wound healing response. Knockdown of claudin 1 or occludin led to changes in proliferation and migration in human skin keratinocytes but not oral keratinocytes. Furthermore, we also showed that skin keratinocytes were more permeable than oral keratinocytes upon histamine treatment. In conclusion, this study highlights a specific subset of functional tight junction genes that are differentially expressed between the oral and skin tissues, which may contribute to the mechanisms leading to distinct healing phenotypes in response to injury in the two tissues.

Myeloid cell-specific sirtuin 6 deficiency delays wound healing in mice by modulating inflammation and macrophage phenotypes

We recently reported that myeloid cell-expressed sirtuin 6 (Sirt6) plays a crucial role in M1 macrophage polarization and chemotaxis. Given the prominent role of macrophages during wound repair and macrophage heterogeneity, we hypothesized that a Sirt6 deficiency in myeloid cells would delay skin wound closure by affecting the phenotypes of macrophages in wounds. To address this question, a full-thickness excisional lesion was made in the dorsal skin of myeloid cell-specific Sirt6 knockout (KO) and wild-type mice. Wound closure was delayed in the KO mice, which exhibited less collagen deposition, suppressed angiogenesis, and reduced expression of wound healing-related genes compared to the wild-type mice. Using immunohistochemical, flow cytometric, and gene-expression analyses of macrophage subpopulations from wound tissue, we identified increased infiltration of M1 macrophages with a concomitant decrease in M2 macrophage numbers in the KO mice compared to the wild-type mice. Consistent with the in vivo wound closure defects observed in the KO mice, keratinocytes and fibroblasts treated with KO macrophage-derived conditioned medium migrated slower than those treated with wild-type macrophage-derived conditioned medium. An analysis of downstream signaling pathways indicated that impaired Akt signaling underlies the decreased M2 phenotypic switching in KO mice. These results suggest that a macrophage phenotypic switch induced by Sirt6 deficiency contributes to impaired wound healing in mice.

Platelet glycoprotein VI and C-type lectin-like receptor 2 deficiency accelerates wound healing by impairing vascular integrity in mice

Platelets promote wound healing by forming a vascular plug and by secreting growth factors and cytokines. Glycoprotein (GP)VI and C-type lectin-like receptor (CLEC)-2 signal through a (hem)-immunoreceptor tyrosine-based activation motif, which induces platelet activation. GPVI and CLEC-2 support vascular integrity during inflammation in the skin through regulation of leukocyte migration and function, and by sealing sites of vascular damage. In this study, we investigated the role of impaired vascular integrity due to GPVI and/or CLEC-2 deficiency in wound repair using a full-thickness excisional skin wound model in mice. Transgenic mice deficient in both GPVI and CLEC-2 exhibited accelerated skin wound healing, despite a marked impairment in vascular integrity. The local and temporal bleeding in the skin led to greater plasma protein entry, including fibrinogen and clotting factors, was associated with increased fibrin generation, reduction in wound neutrophils and M1 macrophages, decreased level of tumor necrosis factor (TNF)-α, and enhanced angiogenesis at day 3 after injury. Accelerated wound healing was not due to developmental defects in CLEC-2 and GPVI double-deficient mice as similar results were observed in GPVI-deficient mice treated with a podoplanin-blocking antibody. The rate of wound healing was not altered in mice deficient in either GPVI or CLEC-2. Our results show that, contrary to defects in coagulation, bleeding following a loss of vascular integrity caused by platelet CLEC-2 and GPVI deficiency facilitates wound repair by increasing fibrin(ogen) deposition, reducing inflammation, and promoting angiogenesis.

Fibroblast growth factors: key players in regeneration and tissue repair

Tissue injury initiates a complex repair process, which in some organisms can lead to the complete regeneration of a tissue. In mammals, however, the repair of most organs is imperfect and results in scar formation. Both regeneration and repair are orchestrated by a highly coordinated interplay of different growth factors and cytokines. Among the key players are the fibroblast growth factors (FGFs), which control the migration, proliferation, differentiation and survival of different cell types. In addition, FGFs influence the expression of other factors involved in the regenerative response. Here, we summarize current knowledge on the roles of endogenous FGFs in regeneration and repair in different organisms and in different tissues and organs. Gaining a better understanding of these FGF activities is important for appropriate modulation of FGF signaling after injury to prevent impaired healing and to promote organ regeneration in humans.

The Regulatory Function of Eosinophils

Eosinophils are a minority circulating granulocyte classically viewed as being involved in host defense against parasites and promoting allergic reactions. However, a series of new regulatory functions for these cells have been identified in the past decade. During homeostasis, eosinophils develop in the bone marrow and migrate from the blood into target tissues following an eotaxin gradient, with interleukin-5 being a key cytokine for eosinophil proliferation, survival, and priming. In multiple target tissues, eosinophils actively regulate a variety of immune functions through their vast arsenal of granule products and cytokines, as well as direct cellular interaction with cells in proximity. The immunologic regulation of eosinophils extends from innate immunity to adaptive immunity and also involves non-immune cells. Herein, we summarize recent findings regarding novel roles of murine and human eosinophils, focusing on interactions with other hematopoietic cells. We also review new experimental tools available and remaining questions to uncover a greater understanding of this enigmatic cell.

Induced histamine regulates Ni elution from an implanted Ni wire in mice by downregulating neutrophil migration

Histamine regulates various inflammatory reactions. We have reported that the expression of histidine decarboxylase (HDC) was induced by subcutaneous implantation of nickel (Ni) wire. However, the source and functions of histamine in Ni elution and Ni wire-induced inflammation have not been completely studied. We aimed to elucidate the effects of de novo synthesized histamine on leucocyte infiltration and Ni elution. Implantation of Ni wire induced an increase in the Ni ion content of the surrounding tissues and serum and in the mRNA levels of HDC, a histamine-producing enzyme, macrophage inflammatory protein-2 (MIP-2), a chemoattractant for neutrophils, and monocyte chemoattractant protein-1 (MCP-1), a chemoattractant for monocytes. The Ni wire induced HDC expression even in mast cell-deficient WBB6F1-W/W^V mice. In HDC knockout (HDC KO) mice, the Ni wire-induced increase in MIP-2 mRNA expression was significantly higher than that in wild-type mice but not MCP-1. MIP-2 expression was enhanced in histamine H2 receptor knockout (H2R KO) mice but not in WBB6F1-W/W^V mice. Histamine inhibited NiCl₂ -induced MIP-2 mRNA expression in mouse bone marrow-derived macrophages (BMDMs) obtained from wild-type mice; this inhibition was not observed in BMDMs from H2R KO mice. Ni elution increased in HDC KO mice, in which leucocyte infiltration also increased, and was suppressed in mice treated with neutrophil-specific antibody. These results suggest that the Ni wire induced HDC expression in non-mast cells and that, in the chronic phase of inflammation, endogenous histamine reduced Ni elution, probably through regulation of MIP-2 expression and neutrophil migration.

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.

Stimulatory effects of histamine on migration of nasal fibroblasts

BACKGROUND

Fibroblast migration is crucial for normal wound repair after sinonasal surgery. Histamine is known to be involved in wound healing by its effects on cell proliferation and migration. This study aimed to determine whether histamine affects the migration of nasal fibroblasts and to investigate the mechanism of action of histamine on nasal fibroblasts.

METHODS

Primary cultures of nasal fibroblasts were established from inferior turbinate samples. Fibroblast migration was evaluated with scratch assays. Cells were treated with histamine and/or histamine receptor-selective antagonists. U-73122 and pertussis toxin, which are selective inhibitors of the lower signaling pathway of H1R and H4R, were used to confirm the modulation of nasal fibroblast migration by histamine. Fibroblast cytoskeletal structures were visualized with immunocytochemistry.

RESULTS

Histamine significantly stimulated the migration of nasal fibroblasts. Antagonists selective for HR1 and HR4 significantly reduced nasal fibroblast migration. In immunocytochemical staining, histamine treatment increased membrane ruffling and pyrilamine, diphenhydramine, fexofenadine, and JNJ7777120 decreased histamine-induced membrane ruffling. U-73122 and pertussis toxin also decreased histamine-induced migration of fibroblasts. Histamine maintains its stimulatory effects on fibroblast migration in the presence of mitomycin C, which blocks proliferation of cells.

CONCLUSION

We showed that histamine stimulates fibroblast migration in nasal fibroblasts. This effect appeared to be mediated by HR1 and HR4. However, because fibroblast migration also can be involved in scaring and fibrosis, more research is necessary to determine the effects of antihistamine on wound healing after sinus surgery.

Multivariate inference of pathway activity in host immunity and response to therapeutics

Developing a quantitative view of how biological pathways are regulated in response to environmental factors is central for understanding of disease phenotypes. We present a computational framework, named Multivariate Inference of Pathway Activity (MIPA), which quantifies degree of activity induced in a biological pathway by computing five distinct measures from transcriptomic profiles of its member genes. Statistical significance of inferred activity is examined using multiple independent self-contained tests followed by a competitive analysis. The method incorporates a new algorithm to identify a subset of genes that may regulate the extent of activity induced in a pathway. We present an in-depth evaluation of specificity, robustness, and reproducibility of our method. We benchmarked MIPA's false positive rate at less than 1%. Using transcriptomic profiles representing distinct physiological and disease states, we illustrate applicability of our method in (i) identifying gene–gene interactions in autophagy-dependent response to Salmonella infection, (ii) uncovering gene–environment interactions in host response to bacterial and viral pathogens and (iii) identifying driver genes and processes that contribute to wound healing and response to anti-TNFα therapy. We provide relevant experimental validation that corroborates the accuracy and advantage of our method.

Physiology and pathophysiology of carnosine

Carnosine (β-alanyl-l-histidine) was discovered in 1900 as an abundant non-protein nitrogen-containing compound of meat. The dipeptide is not only found in skeletal muscle, but also in other excitable tissues. Most animals, except humans, also possess a methylated variant of carnosine, either anserine or ophidine/balenine, collectively called the histidine-containing dipeptides. This review aims to decipher the physiological roles of carnosine, based on its biochemical properties. The latter include pH-buffering, metal-ion chelation, and antioxidant capacity as well as the capacity to protect against formation of advanced glycation and lipoxidation end-products. For these reasons, the therapeutic potential of carnosine supplementation has been tested in numerous diseases in which ischemic or oxidative stress are involved. For several pathologies, such as diabetes and its complications, ocular disease, aging, and neurological disorders, promising preclinical and clinical results have been obtained. Also the pathophysiological relevance of serum carnosinase, the enzyme actively degrading carnosine into l-histidine and β-alanine, is discussed. The carnosine system has evolved as a pluripotent solution to a number of homeostatic challenges. l-Histidine, and more specifically its imidazole moiety, appears to be the prime bioactive component, whereas β-alanine is mainly regulating the synthesis of the dipeptide. This paper summarizes a century of scientific exploration on the (patho)physiological role of carnosine and related compounds. However, far more experiments in the fields of physiology and related disciplines (biology, pharmacology, genetics, molecular biology, etc.) are required to gain a full understanding of the function and applications of this intriguing molecule.

Effect of bone marrow derived mesenchymal stem cells on healing of induced full-thickness skin wounds in albino rat

BACKGROUND AND OBJECTIVES

Mesenchymal stem cells have delivered new approaches to the management of wound healing in severe skin injuries. This work was planned to evaluate the effect of bone marrow-derived mesenchymal stem cells (BMSCs) on healing of induced full thickness skin wounds in albino rats using topical & systemic injections.

METHODS AND RESULTS

Forty adult male albino rats were classified into 2 groups after induction of full thickness skin wound; untreated group and stem cell-treated group. The latter was further subdivided into topically and systemically treated ones. BMSCs were isolated & labeled by PKH26 before injection. Healing of wounds was evaluated grossly. Skin biopsies were obtained one & three weeks after wound induction. Sections were stained with Hematoxylin & Eosin, Masson's trichrome and immunohistochemichal stain for vascular endothelial growth factor (VEGF). Epidermal thicknesses and mean area percent of both collagen fibers & VEGF immunopositive cells were measured using image analyzer & results were subjected to statistical analysis. PKH26 fluorescent-labeled cells were found in the regenerated epidermis, hair follicles and dermis in BMSCs-treated groups. By the end of the third week, the wounds of BMSCs-treated groups showed full regeneration of epidermis, re-organization of collagen and decrease in VEGF immunopositive cells. Delayed wound healing was seen in 20% of systemically treated rats. Significant increase in the mean area percent of collagen fibers was detected in topically treated group.

CONCLUSIONS

Both methods of BMSCs injection were effective in healing of full thickness skin wound but topical method was more effective.

Full-thickness skin wound healing using human placenta-derived extracellular matrix containing bioactive molecules

The human placenta, a complex organ, which facilitates exchange between the fetus and the mother, contains abundant extracellular matrix (ECM) components and well-preserved endogenous growth factors. In this study, we designed a new dermal substitute from human placentas for full-thickness wound healing. Highly porous, decellularized ECM sheets were fabricated from human placentas via homogenization, centrifugation, chemical and enzymatic treatments, molding, and freeze-drying. The physical structure and biological composition of human placenta-derived ECM sheets dramatically supported the regeneration of full-thickness wound in vivo. At the early stage, the ECM sheet efficiently absorbed wound exudates and tightly attached to the wound surface. Four weeks after implantation, the wound was completely closed, epidermic cells were well arranged and the bilayer structure of the epidermis and dermis was restored. Moreover, hair follicles and microvessels were newly formed in the ECM sheet-implanted wounds. Overall, the ECM sheet produced a dermal substitute with similar cellular organization to that of normal skin. These results suggest that human placenta-derived ECM sheets provide a microenvironment favorable to the growth and differentiation of cells, and positive modulate the healing of full-thickness wounds.

Postexercise hypotension and sustained postexercise vasodilatation: what happens after we exercise?

A single bout of aerobic exercise produces a postexercise hypotension associated with a sustained postexercise vasodilatation of the previously exercised muscle. Work over the last few years has determined key pathways for the obligatory components of postexercise hypotension and sustained postexercise vasodilatation and points the way to possible benefits that may result from these robust responses. During the exercise recovery period, the combination of centrally mediated decreases in sympathetic nerve activity with a reduced signal transduction from sympathetic nerve activation into vasoconstriction, as well as local vasodilator mechanisms, contributes to the fall in arterial blood pressure seen after exercise. Important findings from recent studies include the recognition that skeletal muscle afferents may play a primary role in postexercise resetting of the baroreflex via discrete receptor changes within the nucleus tractus solitarii and that sustained postexercise vasodilatation of the previously active skeletal muscle is primarily the result of histamine H(1) and H(2) receptor activation. Future research directions include further exploration of the potential benefits of these changes in the longer term adaptations associated with exercise training, as well as investigation of how the recovery from exercise may provide windows of opportunity for targeted interventions in patients with hypertension and diabetes.

Role of cytokines in lavage or drainage fluid after hemithyroidectomy in wound healing: involvement of histamine in the acceleration and delay of wound healing

Wound healing is a sophisticated biologic process. In the case of hemithyroidectomy, the operation time is relatively short with small tissue damage and without skin excision, and bacterial contamination before, during, and after the operation is uncommon. Here, we explored which cytokine(s) affected the rates of healing of skin wounds after hemithyroidectomy of 29 patients. We assessed the amounts of cytokines (e.g., interleukin-6, platelet-derived growth factor, basic fibroblast growth factor, vascular endothelial growth factor, and tumor necrosis factor-α) in either the preoperative or postoperative lavage fluids, or in the drainage fluids on postoperative days (PODs) 1-8. All of these cytokines showed a similar pattern; after reaching a peak on POD1, the production fell sharply on POD2-8, revealing that wound healing commenced on POD1. The rates of wound healing were inversely related to the levels of histamine in six patients (i.e., those with the three largest and those with the three smallest total volumes of drainage fluid on POD1): high (or low) levels of histamine in the postoperative lavage fluids with low (or high) levels in the drainage fluids on POD1 caused earlier (or the delay of) wound healing, suggesting involvement of histamine in the acceleration and delay of wound healing.

Effects of ginsenoside Rb₁ on skin changes

Ginseng roots (Panax ginseng CA Meyer) have been used traditionally for the treatment, especially prevention, of various diseases in China, Korea, and Japan. Both experimental and clinical studies suggest ginseng roots to have pharmacological effects in patients with life-style-related diseases such as non-insulin-dependent diabetic mellitus, atherosclerosis, hyperlipidemia, and hypertension. The topical use of ginseng roots to treat skin complaints including atopic suppurative dermatitis, wounds, and inflammation is also described in ancient Chinese texts; however, there have been relatively few studies in this area. In the present paper, we describe introduce the biological and pharmacological effects of ginsenoside Rb₁ isolated from Red ginseng roots on skin damage caused by burn-wounds using male Balb/c mice (in vivo) and by ultraviolet B irradiation using male C57BL/6J and albino hairless (HR-1) mice (in vivo). Furthermore, to clarify the mechanisms behind these pharmacological actions, human primary keratinocytes and the human keratinocyte cell line HaCaT were used in experiments in vitro.

Fibroblast growth factor 2 is a key determinant of vascular sprouting during bovine luteal angiogenesis

Fibroblast growth factor (FGF) 2 and vascular endothelial growth factor (VEGF) A are thought to be key controllers of luteal angiogenesis; however, their precise roles in the regulation and coordination of this complex process remain unknown. Thus, the temporal and spatial patterns of endothelial network formation were determined by culturing mixed cell types from early bovine corpora lutea on fibronectin in the presence of FGF2 and VEGFA (6 h to 9 days). Endothelial cells, as determined by von Willebrand factor immunohistochemistry, initially grew in cell islands (days 0–3), before undergoing a period of vascular sprouting to display a more tubule-like appearance (days 3–6), and after 9 days in culture had formed extensive intricate networks. Mixed populations of luteal cells were treated with SU1498 (VEGF receptor 2 inhibitor) or SU5402 (FGF receptor 1 inhibitor) or control on days 0–3, 3–6 or 6–9 to determine the role of FGF2 and VEGFA during these specific windows. The total area of endothelial cells was unaffected by SU1498 treatment during any window. In contrast, SU5402 treatment caused maximal reduction in the total area of endothelial cell networks on days 3–6 vs controls (mean reduction 81%;P<0.001) during the period of tubule initiation. Moreover, SU5402 treatment on days 3–6 dramatically reduced the total number of branch points (P<0.001) and degree of branching per endothelial cell island (P<0.05) in the absence of changes in mean island area. This suggests that FGF2 is a key determinant of vascular sprouting and hence critical to luteal development.

Ação da terapia com laser de baixa potência nas fases iniciais do reparo tecidual: princípios básicos

O objetivo do estudo foi revisar a literatura a respeito da terapia com laser de baixa potência e sua relação com as fases iniciais de reparo. Foram analisados 22 artigos, observando-se a utilização de diferentes doses e comprimentos de ondas (632,8 a 904 nm). Nos estudos in vitro, foram utilizadas doses entre 2,2 e 16 J/cm². A dose de 5 J/cm² tem sido apontada como responsável por mudanças significativas in vitro; porém, a dose de 16 J/cm² promove efeito inibitório sobre o crescimento celular em culturas. Em estudos in vivo, envolvendo animais, foram utilizadas doses entre 0,04 a 21 J/cm². Para estudos em humanos, foram utilizadas doses entre 1,8 a 16 J/cm². Conclui-se que a terapia com laser de baixa potência exerce efeitos anti-inflamatórios importantes nos processos iniciais da cicatrização: redução de mediadores químicos, de citocinas, do edema, diminuição da migração de células inflamatórias e incremento de fatores de crescimento, contribuindo diretamente para o processo de reabilitação tecidual. Porém, a falta de padronização dificulta a escolha de parâmetros ideais.

Histamine synthesis and lessons learned from histidine decarboxylase deficient mice

This chapter summarizes the information about the transcriptional regulation of histidine decarboxylase (HDC), which is the catabolic enzyme of histamine synthesis, and the activity of histamine in vivo as clarified using HDC gene deficient mice (HDC-KO). The research of the regulatory mechanism of histamine synthesis has been focused on transcriptional and posttranslational aspects. The generation ofHDC-KO mice clarified several new pathophysiological functions of histamine. It is now recognized that the activity of histamine is not limited to allergic, peptic and neurological functions as in the old paradigm, but extends to other fields such as cardiology, immunology and infectious diseases. Therefore, this chapter will focus on these newly revealed functions of histamine. For example, histamine was known to be involved in the effector phase of allergic responses, but a role has now been shown in the sensitization phases and in innate immunity. In the allergic bronchial asthma model using HDC-KO mice it was found that histamine positively controls eosinophilia, but not bronchial hypersensitivity. The effect on eosinophils was afterwards shown to be mediated through the activity of the histamine H4 receptor. The recent advances in the understanding of histamine synthesis and the activity of HDC have dramatically expanded our understanding of the scope of histamine function.

Increased synthesis of vascular endothelial growth factor in allergic airway inflammation in histidine decarboxylase knockout (HDC(-/-)) mice

Histamine and vascular endothelial growth factor (VEGF) have been implicated in the pathogenesis of allergic asthma; they enhance inflammation, vascular permeability, and mucus secretion. Histamine was suggested to alter the level of VEGF via the H2 receptors. Here the authors have applied histidine decarboxylase gene-targeted (HDC(-/-)) mice, lacking histamine, to investigate the effect of histamine deficiency on VEGF expression in an animal model of asthma. HDC(-/-) and wild-type (WT) mice were sensitized and challenged with ovalbumin (OVA). VEGF mRNA expression and protein level were determined in the lung. Number of VEGF-positive immune cells of bronchoalveolar lavage (BAL) and their intracellular VEGF content were measured by flow cytometry. VEGF protein level in the lung and in the BAL cells was increased in OVA treated (HDC(-/-)(ova) as well as in WT(ova)) animals compared to their controls. However, there was no difference in the VEGF levels between HDC(-/-) or WT animals, either in the lung or in the BAL cells. In conclusion, increased VEGF production of the lung or BAL immune cells can be induced by allergen provocation independently from the genetic background of the animals. These data suggest that VEGF-mediated allergic processes can persist in the absence of histamine.

Emedastine difumarate: a review of its potential ameliorating effect for tissue remodeling in allergic diseases

BACKGROUND

Emedastine difumarate, a selective histamine-H1 receptor antagonist and effective antiallergic agent, inhibits various clinical symptoms of allergic rhinitis, allergic conjunctivitis, urticaria, allergic dermatitis, pruritus cutaneous, and prurigo. In addition to greater efficacy than other antihistamines, emedastine difumarate produces no adverse cardiovascular effects and exhibits minimal anticholinergic activity. Moreover, a recent study revealed that the effect of emedastine difumarate on inhibition of histamine-induced collagen synthesis in vitro was greater in dermal fibroblasts than in nasal mucosa fibroblasts. This result indicates that there are tissue-specific effects of emedastine difumarate and that it may be more effective for treating fibrosis in skin than in nasal mucosa. However, the mechanism and role of tissue remodeling is less well established for allergic skin diseases and allergic conjunctivitis, in comparison to respiratory allergic diseases.

OBJECTIVE

This review outlines the involvement of histamine in the pathogenesis of tissue remodeling in a variety of organs, and presents the evidence for the effect of antihistamines on this process. Furthermore, this review also discusses antihistamines as an intervention strategy in tissue remodeling.

METHODS

The scientific literature, published abstracts, and selected textbooks were reviewed.

RESULTS/CONCLUSION

Although additional evidence is required, emerging evidence suggests that emedastine difumarate may be of value in the prevention of excess tissue remodeling in allergic skin inflammation.

Histamine induces human beta-defensin-3 production in human keratinocytes

BACKGROUND

The antimicrobial peptide human beta-defensin-3 (hBD-3) is produced by epidermal keratinocytes, and promotes cutaneous antimicrobial defense, inflammation, and wound repair. hBD-3 induces histamine release from mast cells. We previously showed that histamine enhanced transcriptional activity of activator protein-1 (AP-1) in human keratinocytes by inducing the expression of AP-1 component c-Fos via the activation of extracellular signal-regulated kinase (ERK) through H1 receptors.

OBJECTIVE

To examine in vitro effects of histamine on hBD-3 production in normal human keratinocytes.

METHODS

The hBD-3 production was examined by enzyme-linked immunosorbent assays and reverse transcription-polymerase chain reaction. The transcriptional activities were analyzed by dual luciferase assays. The phosphorylation of proteins was examined by Western blotting.

RESULTS

Histamine enhanced hBD-3 secretion and mRNA expression in keratinocytes. The histamine-induced hBD-3 production was suppressed by H1 antagonist pyrilamine and antisense oligonucleotides against signal transducer and activator of transcription 3 (STAT3) and AP-1 components c-Jun and c-Fos. Histamine enhanced STAT3 transcriptional activity and induced tyrosine and serine phosphorylation of STAT3. The former was suppressed by Janus kinase 2 (JAK2) inhibitor AG490, while the latter was suppressed by mitogen-activated protein kinase kinase (MEK) inhibitor PD98059; both were suppressed by pyrilamine. AG490 and PD98059 suppressed histamine-induced hBD-3 production and STAT3 activity. Histamine induced tyrosine phosphorylation of JAK2, and pyrilamine suppressed the phosphorylation.

CONCLUSION

It is suggested that histamine induces hBD-3 production in human keratinocytes through H1 receptors by activating STAT3 and AP-1 via JAK2 and MEK/ERK. Histamine may promote cutaneous antimicrobial defense, inflammation, and wound repair through hBD-3.

FGF2 is crucial for the development of bovine luteal endothelial networks in vitro

The development of the corpus luteum requires angiogenesis, and involves the complex interplay between factors such as vascular endothelial growth factor A (VEGFA), fibroblast growth factor 2 (FGF2) and platelet-derived growth factor (PDGF). However, the relative role of these factors remains to be elucidated. This study used a new physiologically relevant mixed luteal cell culture system to test the hypotheses that: a) FGF2 and VEGFA are critical for bovine luteal angiogenesis; and b) local luteal PDGF signalling stimulates the formation of endothelial networks. Cells were treated with receptor tyrosine kinase inhibitors against VEGFA (SU1498), FGF2 (SU5402) or PDGF (AG1295) activity. After 9 days in culture, endothelial cells were immunostained for von Willebrand factor (VWF) and quantified by image analysis. Highly organised intricate endothelial networks were formed in the presence of exogenous VEGFA and FGF2. The inhibition of FGF2 activity reduced the total area of VWF staining versus controls (>95%; P<0.001). Inhibition of VEGF and PDGF activity reduced the endothelial network formation by more than 60 and 75% respectively (P<0.05). Progesterone production increased in all treatments from day 1 to 7 (P<0.001), and was unaffected by FGF2 or PDGF receptor kinase inhibition (P>0.05), but was reduced by the VEGF receptor inhibitor on days 5 and 7 (P<0.001). In conclusion, this study confirmed that VEGF signalling regulates both bovine luteal angiogenesis and progesterone production. However, FGF2 was crucial for luteal endothelial network formation. Also, for the first time, this study showed that local luteal PDGF activity regulates bovine luteal endothelial network formation in vitro.

Clinical study of external application of Qiyu oil gauze for promoting post-operational healing in patients with anal fistula

OBJECTIVE

To observe the effects of the external application of Qiyu oil gauze (QYOG) for promoting post-operational healing in patients with anal fistula and to explore its mechanism of action so as to provide a beneficial scientific basis for its wide use.

METHODS

Sixty patients with anal fistula scheduled to receive simple low anal fistulectomy were equally assigned, according to the sequence of hospitalization, to the tested group and the control group, and their wounds were classified according to longitudinal diameter into three grades (Grade I with a diameter below 2 cm; Grade II, 2-5 cm; and Grade III, over 5 cm). After the operation was completed and the operational wound was sterilized with benzalkonium bromide, the wound substratum was packed with QYOG in the test group and with vaseline gauze in the control group. The packing gauze was changed every day till the wound was healed. The healing time of the patients was observed, and the number of capillaries and positive cell percentages of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF) in wound granulation tissues were counted on the 5th day after the operation.

RESULTS

The wound healing time was 17.80+/-5.46 days in the test group, which was significantly shorter than that in the control group (21.90+/-6.32 days, P<0.01). The number of capillaries and positive cell percentages of VEGF and bFGF in wound granulation tissues on the 5th day in the tested group were higher than those in the control group (P<0.01), though the difference in EGF between the two groups was insignificant (P>0.05).

CONCLUSION

QYOG could shorten the wound healing time after anal fistulectomy, which suggests that it participates in the stimulation of wound granulation tissues to produce VEGF and bFGF, and thus promotes capillary genesis and improves blood circulation in wounds so as to promote wound healing.