The role of epidermal growth factor in the healing tympanic membrane following perforation in rats

Effect of Growth Factor-Loaded Acellular Dermal Matrix/MSCs on Regeneration of Chronic Tympanic Membrane Perforations in Rats

The success rate of grafting using acellular dermal matrix (ADM) for chronic tympanic membrane was reported in previous studies to be lower than fascia or perichondrium. Combining mesenchymal stem cells (MSCs) and growth factor-loaded ADM for the regeneration of chronic TMP has not been reported so far. In this study, we hypothesized that combining growth factor-loaded ADM/MSCs could promote the recruitment of MSCs and assist in TMP regeneration. We evaluated the regeneration and compared the performance of four scaffolds in both in vitro and in vivo studies. MTT, qPCR, and immunoblotting were performed with MSCs. In vivo study was conducted in 4 groups (control; ADM only, ADM/MSC, ADM/MSC/bFGF, ADM/MSC/EGF) of rats and inferences were made by otoendoscopy and histological changes. Attachment of MSCs on ADM was observed by confocal microscopy. Proliferation rate increased with time in all treated cells. Regeneration-related gene expression in the treated groups was higher. Also, graft success rate was significantly higher in ADM/MSC/EGF group than other groups. Significant relationships were disclosed in neodrum thickness between each group. The results suggest, in future, combining EGF with ADM/MSCs could possibly be used as an outpatient treatment, without the need for surgery for eardrum regeneration.

Application of mesenchymal stem cell for tympanic membrane regeneration by tissue engineering approach

Regeneration is a biological process of cell renewal that takes place in damaged tissues or organs. It is naturally stimulated by the release of different growth factors, cytokines, surface molecules, and stem cells at the wounded sites. The tympanic membrane (TM) is an essential component of the hearing process in the auditory system, which can amplify and transmit sound vibrations through a chain of mobile ossicles. Middle ear infection, external sound pressure, insertion of sharp objects into the ear, and severe trauma are the main causes of TM perforations (TMPs), which could result in deficient hearing function. So far, otolaryngologists have employed surgical procedures (myringoplasty or tympanoplasty) to close the perforated eardrum. Because of limitations such as side effects, discomfort, and high cost to patients, there is a need for better alternatives to surgical procedures. Tissue engineering is a promising tool that can overcome the operational risk and restore, maintain, and improve the function of the TM using a range of biocompatible scaffolds, commercially available growth factors, and stem cells. Currently, multipotent mesenchymal stem cells (MSCs) are a good therapeutic option for the treatment of TMPs because of their self-renewing, and autocrine and paracrine activities. As there are fewer risks of isolation in the use of MSCs for the treatment of TMPs, they are more advantageous for tissue regeneration. The delivery of either MSCs alone or a combination of MSCs with biomaterials and growth factors (GFs) at the ruptured TM sites may enhance the activation of epithelial stem cell markers and increase the migration and proliferation of keratinocytes resulting in faster closure of TMPs. This review focuses on the current strategies used to treat TMPs and the importance of MSCs in TM regeneration. Particularly, we have discussed the synergistic effect of MSCs and scaffolds or GFs or scaffolds/GFs in TM regeneration. Finally, with the advancement of tissue engineering technologies such as 3D and 4D bioprinting, MSCs can be used to design patient-specific scaffolds, which may contain physical and chemical guidance cues to improve the extent and rate of targeted tissue regeneration.

Dose- and starting time-dependent effect of the application of EGF to the regeneration of traumatic eardrum

Background: Some studies have shown that topical application of epidermal growth factor (EGF) accelerates healing in traumatic tympanic membrane perforations (TMPs), however, the optimal dose and starting time of application have not been established.Objectives: To determine the optimal dose and starting time of application of EGF for the regeneration of TMPs.Methods and materials: Patients with traumatic TMPs were first randomly assigned to low-dose EGF, high-dose EGF, and spontaneous healing groups. Then, the same patients were retrospectively analyzed at 6 months based on the starting time of treatment. The closure times, closure rates, and hearing gain were compared among the groups at 6 months.Results: The mean closure time was 10.20 ± 5.13 days in the low-dosage EGF group, 14.39 ± 6.20 days in the high-dosage EGF group, and 33.17 ± 16.37 days in the spontaneous healing group; the difference was significant (p < .001).Conclusions: Daily application of EGF shortened the closure time of traumatic TMPs compared with those that healed spontaneously. However, high-dose EGF instead prolonged the closure time compared to low-dose EGF.

The effect of epidermal growth factor on the pseudo-healing of traumatic tympanic membrane perforations

INTRODUCTION

Traumatic tympanic membrane perforations tend to heal spontaneously. However, in this study, several perforations exhibited abnormal healing, where the morphology of healing tympanic membranes differed from that of non-perforated tympanic membranes. Pseudo-healing of the tympanic membrane was characterized by the accumulation of thickened tissue in the perforated area.

OBJECTIVE

The purpose of this study was to evaluate the utility of epidermal growth factor in cases showing pseudo-healing of traumatic tympanic membrane perforations.

METHODS

A total of 26 traumatic tympanic membrane perforations showing pseudo-healing were included in this study. In all cases, tissue that accumulated in the perforated area was removed, which subsequently caused a new perforation to form. An epidermal growth factor solution was applied to the tympanic membrane once daily to keep the tympanic membrane moist. Closure rates and times were evaluated at 6 months.

RESULTS

During the 6 months follow-up period, two patients were lost. Of the remaining 24 patients, the closure rate was 100% (24/24) and the closure time was 6.1 ± 2.3 days (range: 3-12 days). The morphology of the healed tympanic membrane was not significantly different from that of the remnant tympanic membrane.

CONCLUSIONS

Pseudo-healing of traumatic tympanic membrane perforations affects sound conduction. This can be associated with various symptoms, including tinnitus, aural fullness, and ear discomfort. The excision of excessive epithelial tissue and topical application of epidermal growth factor can correct the pseudo-healing of traumatic tympanic membrane perforations.

Comparative study of epidermal growth factor and observation only on human subacute tympanic membrane perforation

OBJECTIVE

To compare the effects of epidermal growth factor (EGF) and observation only on human subacute tympanic membrane perforation (TMP).

METHODS

A total of 44 patients with traumatic TMPs >2 months after trauma were divided into an observation group (n = 18) and EGF group (n = 26). Patients in the EGF group underwent direct application of EGF without stripping of the perforation edge. All patients were followed up for at least 6 months. The TMP closure rate, closure time, and hearing gain were evaluated.

RESULTS

At 6 months, 25 of 26 (96.2%) perforations achieved complete closure with a mean closure time of 9.1 ± 3.9 days (range, 3-14 days) in the EGF group. However, only 11 of 18 (61.1%) perforations achieved complete closure in the observation group, with a mean closure time of 20.6 ± 10.7 days (range = 9-71 days). The patients in the EGF-treated group had significantly improved closure rates (P = 0.026) and a reduced closure time (P < 0.01) compared to those in the observation group. The difference in mean hearing improvement between the two groups was not statistically significant (P = 0.86).

CONCLUSIONS

Topical application of EGF improved the closure rate and shortened the closure time of human subacute TMPs compared with spontaneous healing, the stripping of the perforation edge was unnecessary. This treatment is simple and convenient and should be recommended pre-myringoplasty.

Pretreatment factors affecting traumatic tympanic membrane regeneration therapy using epidermal growth factor

OBJECTIVE

The use of epidermal growth factor (EGF) to achieve closure of human traumatic tympanic membrane perforations (TMPs) was recently reported. However, pretreatment factors affecting healing outcomes have seldom been discussed. This study was performed to evaluate pretreatment factors contributing to the success or failure of TMP healing using EGF.

DESIGN AND PARTICIPANTS

This was a retrospective cohort study of 95 TMPs who were observed for at least 6 months after EGF treatment. Eleven factors considered likely to affect healing outcome were evaluated by univariate and multivariate logistic regression analyses.

INTERVENTIONS

Each traumatic TMP was treated by daily topical application of EGF. The main outcome measures were complete closure versus failure to close and mean closure time.

RESULTS

A total of 95 patients were included in the analyses. The total closure rate was 92.6% at 6 months, and the mean closure time was 10.5 ± 4.8 days. The closure rate was not significantly different according to the duration of perforation ≤3 days and >3 days (P = 0.816). However, the mean closure time was significantly different according to the duration of perforation (P < 0.001). The perforation size did not affect the closure rate (P = 0.442). The mean closure time in the low-dose EGF group was significantly shorter than that in the high-dose EGF group (P = 0.001). Logistic regression analyses showed that perforations with preexisting myringosclerosis were more likely to fail to close compared to those without preexisting myringosclerosis (P = 0.001). Multivariate logistic regression analyses showed that the duration of perforation (P = 0.011), size of perforation (P < 0.001), and involvement of the malleus in perforation (P = 0.005) were factors independently correlated with closure time.

CONCLUSIONS

Daily application of EGF can be used to treat all traumatic TMPs. The size of the perforation and inverted edges did not affect the closure rate, and the most beneficial dosage was sufficient to keep the eardrum moist. Multivariate logistic regression analyses revealed a significant correlation between preexisting myringosclerosis and failure to heal. Nevertheless, the size of perforation, starting time of application, and malleus injury were independent prognostic factors for prolonged healing time.

Efficacy of EGF and Gelatin Sponge for Traumatic Tympanic Membrane Perforations: A Randomized Controlled Study

OBJECTIVE

To compare the outcomes of epidermal growth factor (EGF) and gelatin sponge patch treatments for traumatic tympanic membrane perforations.

STUDY DESIGN

Prospective, randomized, controlled.

SETTING

University-affiliated teaching hospital.

SUBJECTS AND METHODS

In total, 141 perforations encompassing >50% of the eardrum were randomly divided into 3 groups: EGF (n = 47), gelatin sponge patch (n = 47), and observation (n = 47). The edges of the perforations were not approximated. The closure rate, mean closure time, and infection rate were evaluated at 6 months and the related factors analyzed.

RESULTS

A total of 135 perforations were analyzed. At 6 months, the closure rates were 97.8%, 86.7%, and 82.2% in the EGF, gelatin sponge patch, and spontaneous healing groups, respectively (P = .054). The mean ± SD closure time was 11.12 ± 4.60, 13.67 ± 5.37, and 25.65 ± 13.32 days in the EGF, gelatin sponge patch, and spontaneous healing groups, respectively (P < .001). In addition, the presence of infection was not significantly associated with rate of closure in any group.

CONCLUSIONS

As compared with spontaneous healing, daily application of EGF and gelatin sponge patching reduced the closure time of traumatic tympanic membrane perforations. EGF treatment had a higher closure rate and shorter closure time but resulted in otorrhea. By contrast, gelatin sponge patches did not improve the closure rate or cause otorrhea but required repeated patch removal and reapplication. Thus, the appropriate treatment should be selected according to patient need.

A comparative study to evaluate the efficacy of EGF, FGF-2, and 0.3% (w/v) ofloxacin drops on eardrum regeneration

BACKGROUND

Traumatic tympanic membrane perforations (TMPs) tend to spontaneous healing, however, large TMPs usually fail to healing. Clinical and experimental studies had demonstrated that growth factors accelerated the healing of large TMPs. The aim of this study was to compare the effects of growth factors and 0.3% (w/v) ofloxacin drops n the healing of human large TMPs.

METHODS

A total of 184 human large traumatic TMPs were randomly assigned to receive epidermal growth factor (EGF) treatment, fibroblast growth factor-2 (FGF-2) treatment, 0.3% (w/v) ofloxacin drops treatment, and conservative observation (only).

RESULTS

A total of 180 patients were analyzed in this study at the 6-month follow-up. The closure rates of the perforations in the EGF, FGF-2, 0.3% (w/v) ofloxacin drops, and conservative observation groups were 91.11%, 93.18%, 95.65%, and 82.22%, respectively, the closure rates did not significantly differ among the groups (P = .165). Similarly, pairwise comparisons did not reveal any significant between-group differences (P > .0083). However, the difference of the mean closure time was significant among the 4 groups (P < .001), pairwise comparisons showed that closure time was significantly longer in the observational group than in the other 3 groups (P < .001). Nevertheless, no significant difference in mean closure time was evident between any 2 treated groups (P > .0083). The mean hearing gain after 6 months was 11.49 ± 5.88 dB for the EGF group, 10.89 ± 5.16 dB for the FGF-2 group, 10.54 ± 5.56 dB for the ofloxacin group, and 9.29 ± 5.36 dB for the observation group. Differences in hearing improvement rates among the 4 groups were not statistically significant (P = .283).

CONCLUSION

Epidermal growth factor, FGF-2, and 0.3% (w/v) ofloxacin drops accelerated the closure of large TMPs compared with conservative treatment. Surprisingly, neither the closure rate nor closure time differed significantly among the 3 treated groups. Further experimental studies to demonstrate whether 0.3% (w/v) ofloxacin per se accelerates the healing of TMPs will be interesting in the future.

Functional Outcomes of Heparin-Binding Epidermal Growth Factor-Like Growth Factor for Regeneration of Chronic Tympanic Membrane Perforations in Mice

We aim to demonstrate that regeneration of chronic tympanic perforations with heparin-binding epidermal growth factor-like growth factor (HB-EGF) delivered by an injectable hydrogel restored hearing to levels similar to that of nonperforated tympanic membranes. Chronic tympanic membrane perforation is currently managed as an outpatient surgery with tympanoplasty. Due to the costs of this procedure in the developed world and a lack of accessibility and resources in developing countries, there is a great need for a new treatment that does not require surgery. In this study, we show in a mouse model through measurement of auditory brainstem response and distortion product otoacoustic emissions that tympanic perforations lead to hearing loss and this can be predominantly recovered with HB-EGF treatment (5 μg/mL). Our animal model suggests a return to function between 2 and 6 months after treatment. Auditory brainstem response thresholds had returned to the control levels at 2 months, but the distortion product otoacoustic emissions returned between 2 and 6 months. We also show how the vibration characteristics of the regenerated tympanic membrane, as measured by laser Doppler vibrometry, can be similar to that of an unperforated tympanic membrane. Using the best available methods for preclinical evaluation in animal models, it is likely that HB-EGF-like growth factor treatment leads to regeneration of chronic tympanic membrane perforations and restoration of the tympanic membrane to normal function, suggesting a potential route for nonsurgical treatment.

A retrospective study of EGF and ofloxacin drops in the healing of human large traumatic eardrum perforation

OBJECTIVE

We evaluated the effects of epidermal growth factor (EGF) and ofloxacin otic drops on the healing of large human traumatic tympanic membrane perforations (TMPs).

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary university hospital.

METHODS

Retrospective case review of patients with traumatic TMP larger than 25% of the TM seen between February 2007 and December 2008. Patients were stratified into EGF drops, ofloxacin drops, and observation groups. The closure rate, closure time, and hearing level were compared among the three groups at 6months.

RESULTS

In total, 120 patients met the inclusion criteria. The total closure rate was 89.2% (107/120) and the total mean closure time was 22.6±7.4days. The closure rates of perforation in the EGF, ofloxacin otic drops, and observation groups were 93.5%, 92.0%, and 82.2%, respectively. The closure rates among the three groups were not statistically different (p=0.19). The mean perforation closure times were 12.6±6.9, 12.9±5.1, and 35.7±9.2days for the EGF, ofloxacin otic drops, and observation groups, respectively. The average closure time in the observation group was significantly longer (p=0.01) than that in the EGF and ofloxacin otic drops groups. However, the closure times in the EGF and ofloxacin otic drops groups were not significantly different (p=0.84).

CONCLUSIONS

The study surprisingly found that both topical application of EGF and ofloxacin otic drops result in more rapid closure compared with spontaneous healing for human large traumatic TMPs. The benefit would be great as a shorter recovery time may reduce health care costs. Therefore, ofloxacin otic drops should be considered in clinics.

No systemic exposure of transtympanic heparin-binding epidermal growth factor like growth factor

CONTEXT

Heparin-binding epidermal growth factor like growth factor (HB-EGF) is an emerging therapeutic for the regeneration of the tympanic membrane (TM).

OBJECTIVE

Our aim was to determine whether the doses of HB-EGF delivered in a sustained release hydrogel into a middle ear mouse model, would be measurable in the systemic circulation. We also aimed to observe, in the scenario that the intended dose was absorbed directly into the circulation, whether these levels could be measured above the background levels of HB-EGF in the circulation.

METHODS

A total of 12 mice had transtympanic injections of 5 μg/ml of HB-EGF contained within a previously described novel hydrogel vehicle, while another 12 mice had intravenous delivery of 10 μg/kg of HB-EGF. Intravenous blood samples were collected at 0-, 3-, 24-, 168-, 288- and 720-h post-injection. A double-antibody sandwich one-step process enzyme-linked immunosorbent assay (ELISA) was used to determine the level of HB-EGF in the serum.

RESULTS

No mice in the transtympanic administration group and no mice in the intravenous administration group were found to have blood level measured above that in the controls.

DISCUSSION

The inability of the positive control to measure levels above background, suggest the total dose used in our studies, even if 100% absorbed into the system circulation is insignificant.

CONCLUSIONS

HB-EGF at the doses and delivery method proposed for treatment of chronic TM perforation in a mouse model are likely to have no measurable systemic effect.

Heparin Binding Epidermal Growth Factor-Like Growth Factor Heals Chronic Tympanic Membrane Perforations With Advantage Over Fibroblast Growth Factor 2 and Epidermal Growth Factor in an Animal Model

HYPOTHESIS

That heparin binding epidermal growth factor-like growth factor (HB-EGF) heals chronic tympanic membrane (TM) perforations at higher rates than fibroblast growth factor 2 (FGF2) and epidermal growth factor (EGF) in an animal model.

BACKGROUND

A nonsurgical treatment for chronic TM perforation would benefit those unable to access surgery or those unable to have surgery, as well as reducing the cost of tympanoplasty. Growth factor (GF) treatments have been reported in the literature with variable success with the lack of a suitable animal providing a major obstacle.

METHODS

The GFs were tested in a validated mouse model of chronic TM perforation. A bioabsorbable hydrogel polymer was used to deliver the GF at a steady concentration as it dissolved over 4 weeks. A control (polymer only, n = 18) was compared to polymer loaded with HB-EGF (5 μg/ml, n = 18), FGF2 (100 μg/ml, n = 19), and EGF (250 μg/ml, n = 19). Perforations were inspected at 4 weeks.

RESULTS

The healing rates, as defined as 100% perforation closure, were control (5/18, 27.8%), HB-EGF (15/18, 83.3%), FGF2 (6/19, 31.6%), and EGF (3/19, 15.8%). There were no differences between FGF2 (p = 0.80) and EGF (p = 0.31) with control healing rates. HB-EGF (p = 0.000001) showed a significant difference for healing. The HB-EGF healed TMs showed layers similar to a normal TM, whereas the other groups showed a lack of epithelial migration.

CONCLUSION

This study confirms the advantage of HB-EGF over two other commonly used growth factors and is a promising nonsurgical treatment of chronic TM perforations.

Topical application of epidermal growth factor with no scaffold material on the healing of human traumatic tympanic membrane perforations

OBJECTIVE

We evaluated the effects of conservative treatment and topical application of epidermal growth factor (EGF) with no scaffold material on the healing of human traumatic tympanic membrane perforations (TMPs).

STUDY DESIGN

Prospective, randomised clinical trial.

METHODS

A prospective analysis was performed between January 2015 and March 2015 for the treatment of human traumatic TMPs. The closure rate, closure time, hearing gain and rate of purulent otorrhoea were compared between the topical application of EGF and conservative treatment.

RESULT

In total, 97 patients were analysed. The total closure rates did not significantly differ between the observation and EGF groups (83.0% versus 92.0%, P = 0.182). The total average closure time in the observation group was significantly longer than in the EGF group (25.1 ± 10.5 versus 11.7 ± 5.2 days, P = 0.001). When the closure rate was evaluated according to perforation size, no significant difference was seen for medium or large perforations (P = 0.18 and 0.21, respectively). When closure time was evaluated according to perforation size, a significant difference was seen for medium and large perforations (P = 0.001).

CONCLUSIONS

This study suggests that topical application of EGF with no scaffold material may significantly shorten the closure time of human traumatic TMPs. Such a shorter recovery time may lead to reduced healthcare costs. This alternative technique to a classic myringoplasty is particularly beneficial and suitable for the closure of large human traumatic TMPs.

Enhanced expression of hepatocyte growth factor in the healing of experimental acute tympanic membrane perforation

OBJECTIVES

The present study was performed to investigate the expression of hepatocyte (HGF), epidermal (EGF) and vascular endothelial (VEGF) growth factors in the course of healing of experimental tympanic membrane (TM) perforations in rats. The goal was to explain the role of these growth factors in the healing process of TM and to assess the possibility of their future application as healing promoters.

METHODS

Seventy rats were used, of which 10 served as controls and the others had their TM perforated. The experimental animals were divided into six subgroups on the basis of time points (01, 03, 05, 07, 09, 15 day after injury). Videootoscopy and histology were employed to assess the morphology of the healing process. The expressions of HGF, EGF and VEGF were evaluated using Western blot analysis. Tissue localization of HGF was determined by the immunofluorescence method.

RESULTS

HGF was hardly detectable in normal TM; however, a significant increase was noted in its expression starting from the third day after injury throughout the follow-up period, with the highest level on day 05. The analysis of HGF tissue localization with immunofluorescence revealed diffuse staining in the cytoplasm of proliferating epithelial cells. The expression of EGF was elevated on the first day after injury, not reaching statistical significance, and then returned to the level observed in the control TM. No significant differences were noted in the expression of VEGF.

CONCLUSION

High expression of HGF during the healing process of acute TM perforations makes it a promising candidate for further studies oriented towards its possible use in augmentation of TM healing.

A new theory on the pathogenesis of acquired cholesteatoma: Mucosal traction

OBJECTIVES/HYPOTHESIS

Although the migration of its squamous outer surface of the tympanic membrane has been well characterized, there is a paucity of data available concerning the migratory behavior of its medial mucosal surface. Existing theories of primary acquired cholesteatoma pathogenesis do not adequately explain the observed characteristics of the disease. We propose a new hypothesis, based upon a conjecture that mucosal membrane interactions are the driving force in cholesteatoma.

STUDY DESIGN

A retrospective chart review and a prospective observational cohort study in rats.

METHODS

After developing the new theory, it was tested through both clinical and experimental observations. To evaluate whether impairment of middle ear mucociliary migration would influence cholesteatoma formation, a retrospective chart review evaluating cholesteatoma occurrence in a sizable population of patients with either primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) was performed. To study mucosal migration on the medial aspect of the tympanic membrane, ink tattoos were monitored over time in a rat model.

RESULTS

No cholesteatomas were identified in either PCD patients (470) or in CF patients (1,910). In the rat model, mucosa of the posterior pars tensa migrated toward the posterior superior quadrant, whereas the mucosa of the anterior pars tensa migrated radially toward the annulus.

CONCLUSION

Mucosal coupling with traction generated by interaction of migrating opposing surfaces provides the first comprehensive theory that explains the observed characteristics of primary acquired cholesteatoma. The somewhat counterintuitive hypothesis that cholesteatoma is fundamentally a mucosal disease has numerous therapeutic implications.

The utility of human fallopian tube mucosa as a novel source of multipotent stem cells for the treatment of autologous reproductive tract injury

INTRODUCTION

Fallopian tube, which is normally discarded in surgical procedures, has proven to be a source of mesenchymal stem cells (MSCs) with increasing evidence. However, fallopian tube mucosa, which can be acquired via non-invasive procedures, is a previously unknown source of MSCs. In the present study, we explored the existence of MSCs in the human fallopian tube mucosa and also compared multipotent stem cells derived from fallopian tubes and fallopian tube mucosa according to their biological characteristics and therapeutic potential for treatment of autologous reproductive tract injury.

METHODS

Cells isolated from human fallopian tubes and fallopian tube mucosa were expanded and characterised by flow cytometry. The proliferative capacity of both cell types was measured by performing colony-forming unit-fibroblast and Cell Counting Kit-8 assays. Both cell types underwent in vitro adipogenic, chondrogenic, and osteogenic differentiation. The expression of osteocyte-, adipocyte-, and chondrocyte-related genes in the differentiated cell lineages was assessed by reverse transcription-polymerase chain reaction. The secretion of growth factors and immunomodulatory cytokines by both cell types were measured by enzyme-linked immunosorbent assays.

RESULTS

We found that MSCs existed in the fallopian tube mucosa. The comparison between human fallopian tube MSCs (hFTMSCs) and human fallopian tube mucosa MSCs (hFMMSCs) showed that hFTMSCs had a stronger proliferative capacity and shorter duplication time than hFMMSCs. Both cell types could be differentiated into adipocytes, osteoblasts, or chondrocytes in vitro. Real-time polymerase chain reaction analysis demonstrated that hFTMSCs displayed increased expression of osteogenic-specific genes compared with hFMMSCs, but the two types of cells showed no significant increase in the mRNA expression of adipogenic-specific or chondrogenic-specific genes. hFMMSCs and hFTMSCs robustly produced a variety of growth factors and immunomodulatory cytokines.

CONCLUSIONS

Human fallopian tube mucosa is a novel source of multipotent cells. hFMMSCs demonstrated stronger proliferative capacity and superior secretion of growth factors and immunomodulatory cytokines than hFTMSCs, making the former a better source of stem cells for the treatment of autologous reproductive tract injury. Compared with fallopian tube, fallopian tube mucosa has more wide-ranging applications and can be used to carry out autologous transplantation.

Effect of recombinant human epidermal growth factor impregnated chitosan film on hemostasis and healing of blood vessels

Background

Bleeding can be a problem in wound debridement. In search for an effective hemostatic agent, we experimented with a chitosan film combined with the recombinant human epidermal growth factor (rh-EGF), hypothesizing that it would achieve effective hemostasis and simultaneously enhance arterial healing.

Methods

Forty-eight Sprague-Dawley rats were used, and 96 puncture wounds were made. The wounds were divided into the following four groups: treated with sterile gauze, treated with gelatin sponge, treated with chitosan, and treated with chitosan combined with rh-EGF. Immediate hemostasis was evaluated, and arterial healing was observed histologically.

Results

Groups B, C, and D showed a significant rate of immediate hemostasis as compared to group A (P<0.05), but there were no significant differences among groups B, C, and D. Histologically, only group D showed good continuity of the vessel wall after 1 week. It was the only group to show smooth muscle cell nuclei of the vessel wall.

Conclusions

We observed that chitosan has an effective hemostatic potential and the mix of rh-EGF and chitosan does not interfere with chitosan's hemostatic capabilities. We also identified enhanced healing of vessel walls when rh-EGF was added to chitosan. Further research based on these positive findings is needed to evaluate the potential use of this combination on difficult wounds like chronic diabetic ulcerations.

Analysis of gene expression profiles in tympanic membrane following perforation using PCR Array in rats--preliminary investigation

OBJECTIVES

The goal of this work was to identify genes, known to be involved in the skin wound healing, that express differentially in the healthy and injured tympanic membrane (TM), and designate the molecules potentially beneficial for treatment of TM perforation. The molecular mechanisms controlling the course of TM regeneration are far from being elucidated.

METHODS

Twenty rats had their tympanic membranes perforated, while four served as a control. Animals were sacrificed on either days 1, 2, 3, 5 and 10 post injury, and TMs were immediately dissected and frozen in liquid nitrogen. Total TM RNA was isolated and reversely transcribed. qPCR was performed using Rat Wound Healing RT(2) Profiler PCR Array (QIAGEN) containing primers for 84 genes.

RESULTS

Statistically significant changes in the expression of 42 genes were found in various stages of TM healing. The increased expression of genes taking part in the inflammatory reaction (interleukin 6, granulocyte and macrophage chemotactic proteins) was observed from day 2. The expression of several genes of extracellular matrix components and their remodeling enzymes was also changed. Among growth factor genes: Vegfa, Igf1 and Hbegf showed increased expression at the beginning of the healing process, while Hgf expression was highest on day 3.

CONCLUSIONS

Several changes in the expression of genes involved in remodeling of extracellular matrix point to important role of connective tissue in TM healing. The molecules accelerating this process, like HbEGF and HGF, seem to be good candidates for further evaluation of their possible use in clinical treatment.

Tissue engineering of the tympanic membrane

Tympanic membrane (TM) perforations are common, with current treatments for chronic perforations involving surgery, using various graft materials, from autologous cartilage or fascia through to paper patch. Recent research developments in this field have begun applying the principles of tissue engineering, with appropriate scaffolds, cells, and bioactive molecules (BMs). This has revolutionized the therapeutic approach due to the availability of a wide range of materials with appropriate compatibility and mechanical properties to regenerate the membrane acoustics and may also represent a paradigm shift in the management of TM perforations in an outpatient setting without surgery. However, many factors need to be considered in the fabrication of a bioengineered TM. This review discusses the issues associated with current treatment and examines TM wound healing relevant to the construction of a bioengineered TM. It also describes the tissue-engineering approach to TM regeneration by summarizing currently used scaffolds, BMs, and cells in TM wound healing. Finally, it considers the design of scaffolds, delivery of BMs, and cell engraftment toward potential clinical application.

Tympanic membrane wound healing in rats assessed by transcriptome profiling

OBJECTIVES/HYPOTHESIS

The aim of this study is to elucidate transcriptional changes that occur in response to tympanic membrane (TM) perforation in rats and to infer key genes and molecular events in the healing process.

STUDY DESIGN

A prospective cohort study of 393 male Sprague-Dawley (Rattus norvegicus) rats.

METHODS

Sprague-Dawley rats were randomly allocated into either control or perforation groups spanning a 7-day time period. Perforation groups consisted of 12-hour, 24-hour, 36-hour, 2-day, 3-day, 4-day, 5-day, six-day, and 7-day time points. The left TMs of all perforation groups were perforated and the RNA extracted at the specified time point postperforation. Subsequent analysis was performed using Agilent's 4 × 44 k whole rat genome arrays (40 in total) to assess wound-healing gene expression over a 7-day time period.

RESULTS

Over a 7-day time course and at nine time points that encompassed the wounding and progression of healing, a total of 3,262 genes were differentially expressed. In this study the transcripts most upregulated occurred at 12 hours. These were Stefin A2 (344-fold), Stefin 2 (143-fold), and Natriuretic peptide precursor type B (222-fold). Those most downregulated also occurred at 12 hours. These were alcohol dehydrogenase 7 (13.1-fold) and gamma-butyrobetaine hydroxylase (10.4-fold). Results were validated by quantitative real-time polymerase chain reaction.

CONCLUSIONS

The findings of this study provide a baseline against which to identify disease-related molecular signatures, biomarkers, and to develop new treatments for TM conditions based on molecular evidence.

Keratinocyte growth factor 1, fibroblast growth factor 2 and 10 in the healing tympanic membrane following perforation in rats

The aim of this study was to provide a transcriptome profile of Keratinocyte Growth Factor (KGF)-1, Fibroblast Growth Factor (FGF) 2 and FGF10 (KGF2) in the healing rat tympanic membrane (TM) over 7 days and an immunohistochemical account over 14 days following perforation. KGF1, FGF2, and FGF10 play important roles in TM wound healing. The tympanic membranes of rats were perforated and sacrificed at time points over a 14-day period following perforation. The normalized signal intensities and immunohistochemical protein expression patterns at each time point for KGF1, FGF2, and FGF10 are presented. The primary role of both KGF1 and FGF2 appeared to be in the proliferation and migration of keratinocytes. Whereas the role of KGF1 appeared to be exclusively concerned with increased proliferation and migration at the perforation site, the continued expression of FGF2, beyond perforation closure, suggested it has an additional role to play. FGF10 (KGF2), whilst possessing the highest sequence homologous to KGF1, has a different role in TM wound healing. The effect of FGF10 on keratinocytes in wound healing appeared to emanate from the connective tissue layer.