Effects of the nerve growth factor on the survival and wound healing in mice with combined radiation and wound injury

Functional reconstruction of the masseter muscle by microvascular free gracilis muscle transfer: technique and outcome

Microvascular reconstruction of the cheek is most often performed using fasciocutaneous flaps and without functional reconstruction of the masseter muscle. This article reports a technique of masseter muscle resection, dissection of the masseteric nerve, and masseter muscle reconstruction with a functional gracilis muscle flap. The technique was applied in a 38-year-old man with recurrent intramuscular lipoma of the right masseter muscle. The flap was highly stable in form and showed good function. Bite force, electromyography results, and the radiological appearance of the gracilis muscle were similar to those of the contralateral masseter muscle at 12 months after surgery. In conclusion, full rehabilitation of masseter muscle function and good facial aesthetics were achieved by functional gracilis muscle reconstruction of the masseter muscle in a case of total resection.

Therapeutic role of growth factors in treating diabetic wound

Wounds in diabetic patients, especially diabetic foot ulcers, are more difficult to heal compared with normal wounds and can easily deteriorate, leading to amputation. Common treatments cannot heal diabetic wounds or control their many complications. Growth factors are found to play important roles in regulating complex diabetic wound healing. Different growth factors such as transforming growth factor beta 1, insulin-like growth factor, and vascular endothelial growth factor play different roles in diabetic wound healing. This implies that a therapeutic modality modulating different growth factors to suit wound healing can significantly improve the treatment of diabetic wounds. Further, some current treatments have been shown to promote the healing of diabetic wounds by modulating specific growth factors. The purpose of this study was to discuss the role played by each growth factor in therapeutic approaches so as to stimulate further therapeutic thinking.

Correlation of chemokines and growth factors with radiation-induced liver injury after interstitial high dose rate (HDR) brachytherapy of liver metastases

Background

Locoregional therapies, as imaging-guided tumor-directed procedures, are emerging treatment strategies in the management of primary and secondary liver malignancies such as e.g. colorectal cancer liver metastases. As one of those, irradiation-based interstitial high dose rate brachytherapy (iBT) of liver metastases bears a risk of developing focal radiation-induced liver injury (fRILI). Since little is known about biological factors involved in hepatic dysfunction after irradiation, the aim of this study was to identify factors, that may play a role in the underlying mechanism of fRILI, and that potentially may serve as biomarkers for post-therapeutic fRILI to improve specific management and treatment of patients.

Methods

Twenty-two patients with hepatic malignancies (tumor patients, TP) underwent iBT with total ablative doses of radiation to the target volume ranging from e.g. 15 to 25 Gy. Hepatobiliary magnetic resonance imaging (MRI) was performed 6 weeks after iBT to quanitify fRILI. Blood samples were taken before (pre) and 6 weeks after (post) iBT from TP, and from ten healthy volunteers (HV controls) for the analyses of humoral mediators: monocyte chemoattractant protein-1 (MCP-1), chemokine (C-X3-C motif) ligand 1 (CX3CL1), vascular endothelial growth factor (VEGF) and beta-nerve growth factor (beta-NGF) using the Multi-Analyte Flow Assay via flow cytometry. Correlation analyses between the humoral mediators (pre and post iBT) with the tumor volume and fRILI were performed.

Results

While MCP-1 and CX3CL1 tended to decrease in TP vs. HV, VEGF was significantly decreased in TP vs. HV pre and post iBT (p < 0.05). Beta-NGF levels were significantly increased in TP vs. HV pre and post iBT (p < 0.05). Baseline circulating levels of MCP-1, VEGF and beta-NGF have shown significant positive correlations with the hepatic tumor volume (p < 0.05). Circulating levels of humoral mediators before treatment did not correlate with fRILI, while CX3CL1 and VEGF after iBT have shown significant positive correlations with fRILI (p < 0.05).

Conclusion

Tumor volume and threshold dose of irradiation damage correlated positively with MCP-1 and VEGF as well as NGF and CX3CL, respectively. Thus, investigation of biological mediators in blood samples from tumor patients may provide an appropriate tool to predict fRILI after interstitial HDR brachytherapy of liver metastases.

Role of NGF and its receptors in wound healing (Review)

Wound healing is an important and complicated process that includes four highly integrated and overlapping phases, haemostasis, inflammation, proliferation and tissue remodelling. Nerve growth factor (NGF) was the first member of a family of neurotrophic factors to be discovered, and is an essential neurotrophic factor for the development and maintenance of the central and peripheral nervous systems. Several studies have proposed that NGF and its receptors, tropomyosin-related kinase receptor 1 and NGF receptor, are involved in the wound healing process, and are important components of the healing of several wounds both in vivo and in vitro. Topical application of NGF significantly promotes the healing of different types of wounds, including diabetic foot ulcers, pressure ulcers and corneal wounds. The present review summarizes the status of NGF and its receptors in current literature, and discusses data obtained in the last few years on the healing action of NGF in cutaneous, corneal and oral wounds.

Hair keratin promotes wound healing in rats with combined radiation-wound injury

Keratins derived from human hair have been suggested to be particularly effective in general surgical wound healing. However, the healing of a combined radiation-wound injury is a multifaceted regenerative process. Here, hydrogels fabricated with human hair keratins were used to test the wound healing effects on rats suffering from combined radiation-wound injuries. Briefly, the keratin extracts were verified by dodecyl sulfate polyacrylamide gel electrophoresis analysis and amino acid analysis, and the keratin hydrogels were then characterized by morphological observation, Fourier transform infrared spectroscopy analysis and rheology analyses. The results of the cell viability assay indicated that the keratin hydrogels could enhance cell growth after radiation exposure. Furthermore, keratin hydrogels could accelerate wound repair and improve the survival rate in vivo. The results demonstrate that keratin hydrogels possess a strong ability to accelerate the repair of a combined radiation-wound injury, which opens up new tissue regeneration applications for keratins.

Trophic Factors in Inflammation and Regeneration: The Role of MANF and CDNF

Regeneration is an important process in multicellular organisms, responsible for homeostatic renewal and repair of different organs after injury. Immune cell activation is observed at early stages of the regenerative response and its regulation is essential for regenerative success. Thus, immune regulators play central roles in optimizing regenerative responses. Neurotrophic factors (NTFs) are secreted molecules, defined by their ability to support neuronal cell types. However, emerging evidence suggests that they can also play important functions in the regulation of immune cell activation and tissue repair. Here we discuss the literature supporting a role of NTFs in the regulation of inflammation and regeneration. We will focus, in particular, in the emerging roles of mesencephalic astrocyte-derived neurotrophic factor (MANF) and cerebral dopamine neurotrophic factor (CDNF) in the regulation of immune cell function and in the central role that immune modulation plays in their biological activity in vivo. Finally, we will discuss the potential use of these factors to optimize regenerative success in vivo, both within and beyond the nervous system.

Human umbilical cord blood-derived mesenchymal stromal cells and small intestinal submucosa hydrogel composite promotes combined radiation-wound healing of mice

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs) are a promising agent for treating impaired wound healing, and their therapeutic potential may be enhanced by employing extracellular matrix scaffolds as cell culture scaffolds or transplant cell carriers. Here, we evaluated the effect of human umbilical cord blood-derived (hUCB)-MSCs and a porcine small intestinal submucosa (SIS)-derived extracellular matrix scaffold in a combined radiation-wound mouse model of impaired wound healing.

METHODS

hUCB-MSCs and SIS hydrogel composite was applied to the excisional wound of whole-body irradiated mice. Assessment of wound closing and histological evaluation were performed in vivo. We also cultured hUCB-MSCs on SIS gel and examined the angiogenic effect of conditioned medium on irradiated human umbilical vein endothelial cells (HUVECs) in vitro.

RESULTS

hUCB-MSCs and SIS hydrogel composite treatment enhanced wound healing and angiogenesis in the wound site of mice. Conditioned medium from hUCB-MSCs cultured on SIS hydrogel promoted the chemotaxis of irradiated HUVECs more than their proliferation. The secretion of angiogenic growth factors hepatocyte growth factor, vascular endothelial growth factor-A and angiopoietin-1 from hUCB-MSCs was significantly increased by SIS hydrogel, with HGF being the predominant angiogenic factor of irradiated HUVECs.

CONCLUSIONS

Our results suggest that the wound healing effect of hUCB-MSCs is enhanced by SIS hydrogel via a paracrine factor-mediated recruitment of vascular endothelial cells in a combined radiation-wound mouse model.

Role of neuropeptides, neurotrophins, and neurohormones in skin wound healing

Due to the close interactions between the skin and peripheral nervous system, there is increasing evidence that the cutaneous innervation is an important modulator of the normal wound healing process. The communication between sensory neurons and skin cells involves a variety of molecules (neuropeptides, neurohormones, and neurotrophins) and their specific receptors expressed by both neuronal and nonneuronal skin cells. It is well established that neurotransmitters and nerve growth factors released in skin have immunoregulatory roles and can exert mitogenic actions; they could also influence the functions of the different skin cell types during the wound healing process.

Collagen scaffolds loaded with collagen-binding NGF-beta accelerate ulcer healing

Studies have shown that exogenous nerve growth factor (NGF) accelerates ulcer healing, but the inefficient growth factor delivery system limits its clinical application. In this report, we found that the native human NGF-beta fused with a collagen-binding domain (CBD) could form a collagen-based NGF targeting delivery system, and the CBD-fused NGF-beta could bind to collagen membranes efficiently. Using the rabbit dermal ischemic ulcer model, we have found that this targeting delivery system maintains a higher concentration and stronger bioactivity of NGF-beta on the collagen membranes by promoting peripheral nerve growth. Furthermore, it enhances the rate of ulcer healing through accelerating the re-epithelialization of dermal ulcer wounds and the formation of capillary lumens within the newly formed tissue area. Thus, collagen membranes loaded with collagen-targeting human NGF-beta accelerate ulcer healing efficiently.

Ghrelin as a novel therapy for radiation combined injury

The threat of nuclear terrorism has led to growing worldwide concern about exposure to radiation. Acute radiation syndrome, or radiation sickness, develops after whole-body or a partial-body irradiation with a high dose of radiation. In the terrorist radiation exposure scenario, however, radiation victims likely suffer from additional injuries such as trauma, burns, wounds or sepsis. Thus, high-dose radiation injuries and appropriate therapeutic interventions must be studied. Despite advances in our understanding of the pathophysiology of radiation injury, very little information is available on the therapeutic approaches to radiation combined injury. In this review, we describe briefly the pathological consequences of ionizing radiation and provide an overview of the animal models of radiation combined injury. We highlight the combined radiation and sepsis model we recently established and suggest the use of ghrelin, a novel gastrointestinal hormone, as a potential therapy for radiation combined injury.

Pharmacological modulation of wound healing in experimental burns

Factors involved in wound healing and their interdependence are not yet fully understood; nevertheless, new prospects for therapy to favor speedy and optimal healing are emerging. Reports about wound healing modulation by local application of simple and natural agents abound even in the recent literature, however, most are anecdotal and lack solid scientific evidence. We describe the effect of silver sulfadiazine and moist exposed burn ointment (MEBO), a recently described burn ointment of herbal origin, on mast cells and several wound healing cytokines (bFGF, IL-1, TGF-beta, and NGF) in the rabbit experimental burn model. The results demonstrate that various inflammatory cells, growth factors and cytokines present in the wound bed may be modulated by application of local agents with drastic effects on their expression dynamics with characteristic temporal and spatial regulation and changes in the expression pattern. Such data are likely to be important for the development of novel strategies for wound healing since they shed some light on the potential formulations of temporally and combinatory optimized therapeutic regimens.

Are Neurotrophins Important in Ulcerative Colitis?

Neurotrophins are known to have growth, survival-promoting, and healing effects. The importance of neurotrophins in ulcerative colitis (UC) is, however, unclear. Recent studies in our group revealed that an occurrence of marked changes in neurotrophin expression patterns was related to a worsening of the disease process. There was thus an upregulation for the lamina propria cells but a downregulation in nerve structures concerning neurotrophin expressions in severe UC. The observations show that changes in the neurotrophin system are a part of the disease process in UC and are of interest as treatments interfering with neurotrophin effects in other situations have been found to have trophic and healing effects.

Radiotherapy and wound healing

Radiotherapy is an invaluable weapon when treating cancer. However, the deleterious effects of radiation, both immediate and long-term, may have a significant effect on local tissues. Problematic wound healing in radiation-damaged tissue constitutes a major problem that is frequently overlooked during the management of patients who require radiotherapy, or have had radiotherapy in the past. Poor wound healing may lead to chronic ulceration, pain, secondary infection and psychological distress and compromise the outcome of general or reconstructive surgery. We discuss the pathophysiology of poor wound healing following radiotherapy, specific problems for radiation-damaged tissue and potential treatments to improve wound healing of irradiated tissues.

A study on the activity of fibroblast cells in connection with tissue recovery in the wounds of skin injury after whole-body irradiation

The 6 Gy of whole-body irradiation (WBI) with gamma rays results in an impairment of injured skin tissue recovery and renders a delay in the healing process. For an understanding of whether WBI has damaging effects on fibroblasts in wounds, fibroblasts in wounds combined with WBI and those of simple incision were isolated and cultivated, and abilities connected with tissue repair, including proliferation, attachment, adhesion, and apoptosis, were determined by direct cell count, immunohistochemical staining for proliferation cell nuclear antigen (PCNA), and TUNEL assay. The results showed that the abilities of proliferation and the attachment and adhesion of fibroblasts from wounds combined with WBI significantly decreased in comparison with those having simple incisions on the 3rd and 5th days of posttrauma, whereas the apoptotic ratio of fibroblasts from wounds combined with WBI significantly increased. These data suggest that WBI may exert damaging effects on fibroblasts in wounds, which might be one of the dominant reasons for the impaired healing of wounds combined with WBI.

Transplantation of dermal multipotent cells promotes the hematopoietic recovery in sublethally irradiated rats

Our previous study indicated that dermal multipotent cells with the differentiation capacity to form cells with the phenotypic properties of osteocytes, adipocytes, chondrocytes, and neurons in specific inducing media could be isolated from the enzymatically dissociated dermal cells of newborn rats by their adherence to culture dish plastic. We have also observed that the systemic transplantation of dermal multipotent cells could not repopulate the hematopoietic system in lethally irradiated rats. In this paper, we found that a transplantation of plastic-adherent dermal multipotent cells into sublethally irradiated rats led to a significant increase of white blood cells in peripheral blood, nucleated cells, CFU-GM, and CFU-F colonies in bone marrow. FISH analysis, using a Y-chromosome specific probe, showed that dermal multipotent cells could engraft into bone marrow in recipients. Flow cytometry (FACS) analysis also showed that the proportion of CD2 and CD25 positive lymphocytes in peripheral blood did not change significantly in two weeks after transplantation. By these results, we infer that dermal multipotent cells may represent an alternative origin of mesenchymal stem cells to restore marrow microenvironment and promote the survival, engraftment, and proliferation of hematopoietic cells.

Nerve growth factor and substance P regulation in nasal sensory neurons after toluene diisocyanate exposure

Toluene diisocyanate (TDI) exposure produces rhinitis and nasal irritation, and increases the synthesis and release of substance P (SP) from airway sensory nerves. The mechanism leading to enhanced SP production following irritant inhalation remains unclear, but may involve actions of nerve growth factor (NGF). NGF binds trkA receptors located on sensory nerve terminals. Activation of trkA receptors initiates kinase-signaling cascades, which ultimately may increase SP. However, the effects of inhaled irritants on NGF release are not known. In this study, NGF levels in nasal lavages were examined following instillation of 10% TDI into both nasal cavities. NGF was significantly increased 2, 6, 12, and 24 h after TDI exposure compared with controls. The increase in NGF preceded the neuronal and mucosal increases in SP. Pretreatment with K252a, a nonselective tyrosine-kinase inhibitor, prevented the increase in SP-immunoreactivity in TG neurons and epithelial nerve fibers and the inflammatory response to TDI exposure. Because NGF binds to trkA tyrosine-kinase receptors, the NGF released during TDI exposure may mediate SP upregulation in airway sensory neurons, innervating the nasal cavity.