Influence of topical application of basic fibroblast growth factor upon inner ear

Tissue engineering and regenerative medicine strategies for the repair of tympanic membrane perforations

Despite the high success rate of autologous grafts in tympanic membrane repair, clinical alternatives are required for the closure of unresponsive chronic perforations that can lead to recurring infection and hearing loss. Tissue engineering and regenerative medicine approaches have emerged as another strategy to repair the eardrum, in addition to negating the need for donor tissue harvest and related surgical iatrogenicities. This review highlights the main approaches using biomaterials, growth factors, and cell therapies towards the healing of complex TM perforations. In addition, we discuss the challenges and advances for the development of reliable animal models, which will allow the optimisation and development of novel techniques. Finally, we indicate technologies that are currently used clinically and others that are closer to the market. The advances here discussed on tissue engineering and regenerative medicine strategies applied to the field of TM perforations will allow otologists, surgeons, and researchers to better bring novel technologies to the bedside as well as to develop new ones.

FGF2 and EGF for the Regeneration of Tympanic Membrane: A Systematic Review

Objective

A systematic review was conducted to compare the effectiveness and safety of fibroblast growth factor-2 (FGF2) and epidermal growth factor (EGF) for regeneration of the tympanic membrane (TM).

Methods

The PubMed database was searched for relevant studies. Experimental and clinical studies reporting acute and chronic TM perforations in relation to two healing outcomes (success rate and closure time) and complications were selected.

Results

A total of 47 studies were included. Five experimental studies showed closure rates of 55%-100% with FGF2 compared with 10%-62.5% in controls for acute perforations. Five experimental studies showed closure rates of 30.3%-100% with EGF and 3.6%-41% in controls for chronic perforations. Two experimental studies showed closure rates of 31.6% or 85.7% with FGF2 and 15.8% or 100% with EGF. Nine clinical studies of acute large perforations showed closure rates of 91.4%-100% with FGF2 or EGF. Two clinical studies showed similar closure rates between groups treated with FGF2 and EGF. Seven clinical studies showed closure rates of 88.9%-100% within 3 months and 58%-66% within 12 months using FGF2 in repair of chronic perforations, but only one study showed a significantly higher closure rate in the saline group compared with the FGF2 group (71.4% vs. 57.5%, respectively, P = 0.547). In addition, three experimental studies showed no ototoxicity associated with FGF2 or EGF. No middle ear cholesteatoma or epithelial pearls were reported, except in one experimental study and one clinical study, respectively.

Conclusions

FGF2 and EGF showed good effects and reliable safety for the regeneration of TM. In addition, EGF was better for the regeneration of acute perforations, while FGF2 combined with biological scaffolds was superior to EGF for chronic perforations, but was associated with high rates of reperforation over time. Further studies are required to determine whether EGF or FGF2 is better for TM regeneration.

The short- and long-term adverse effects of FGF-2 on tympanic membrane perforations

SUMMARY

The objective of this study was to investigate the short- and long-term adverse effects of fibroblast growth factor-2 treatment of tympanic membrane perforations. A total of 134 patients with traumatic tympanic membrane perforations were randomly divided into two groups: an observational group and a fibroblast growth factor-2 treatment group. The closure rate, closure time and principal side-effects were compared between the groups at 6 and 12 months. At 6 months, 131 patients were examined to determine healing outcomes and short-term side-effects. The total closure rate differed significantly between the fibroblast growth factor-2 and observational groups (95.5% vs 73.4, p #x003C; 0.01). The fibroblast growth factor-treated group exhibited a significantly shorter closure time than the observational group (11.9±3.1 days vs 52.6 ± 18.1 days, p = 0.00). Three patients with secondary otitis media with effusion, and three with reperforations, were noted in the fibroblast growth factor-2 group. We additionally performed long-term follow-up on 89.1% of the patients in the observational group and 92.5% of the patients in the fibroblast growth factor-2 group; follow-up was performed 16-42 months after perforation closure. Only a small perforation of the pars flaccida developed in the fibroblast growth factor-2 group. No middle ear cholesteatoma was noted in either group. This study suggests that the topical application of fibroblast growth factor-2 to human traumatic tympanic membranes is safe. Otorrhoea was the most common short-term side-effect; other less common side-effects included otitis media with effusion and reperforation. No serious long-term side-effects were found.

Regeneration of the tympanic membrane using fibroblast growth factor-2

OBJECTIVE

A systematic review was conducted to investigate the effectiveness of fibroblast growth factor-2 on the regeneration of tympanic membrane perforation.

METHODS

The PubMed database was searched for relevant studies. Experimental studies, human randomised controlled trials, prospective single-arm studies and retrospective studies reporting acute and chronic tympanic membrane perforations in relation to two healing outcomes (success rate and closure time), were selected.

RESULTS

All 11 clinical studies investigating the effect of fibroblast growth factor-2 on traumatic tympanic membrane perforations in humans reported a success rate of 89.3-100 per cent, with a closure time of around 2 weeks. Three studies of fibroblast growth factor-2 combined with Gelfoam showed that the success rate of chronic tympanic membrane perforation was 83-98.1 per cent in the fibroblast growth factor-2 group, but 10 per cent in the gelatine sponge groups.

CONCLUSION

Fibroblast growth factor-2 with or without biological material patching promotes regeneration in cases of acute and chronic tympanic membrane perforation, and is safe and efficient. However, the best dosage, application time and administration pathway of fibroblast growth factor-2 are still to be elucidated.

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.

Evaluation of the optimum time for direct application of fibroblast growth factor to human traumatic tympanic membrane perforations

OBJECTIVE

The aim of this study was to determine the optimum time for direct application of basic fibroblast growth factor (bFGF) on large traumatic tympanic membrane perforations (TMPs).

STUDY DESIGN

Prospective clinical study.

SETTING

Tertiary University Hospital.

METHODS

Ninety-three patients, with traumatic TMPs greater in extent than 25% of the entire tympanic membrane, were randomized into observation and bFGF-treated groups (~0.2-0.25 mL of bFGF solution was applied directly onto the TM once daily and continued until the perforation closed). Initial visit times were subcategorized into perforation durations of ≤3 and >3 days, thereby rendering two subgroups, as follows: A and B in the observation group; and C and D in the bFGF-treated group. The closure rate and mean closure time were evaluated after 6 months.

RESULTS

Eighty-six patients were finally analyzed. After 6 months, the bFGF-treated group exhibited a significantly higher total closure rate (97.8 versus 82.5%, p < 0.05) and a shorter mean closure time (12.5 ± 3.4 versus 34.0 ± 5.9 days, p < 0.05) compared with the spontaneous healing group. In addition, in the observation group, visiting time was not associated with differences in closure rate (p > 0.05) and mean closure time (p > 0.05), between the A and B subgroups. Similarly, in the bFGF-treated group, visiting time was not associated with differences in closure rate (p > 0.05) between the C and D subgroups. However, the D subgroup was characterized by significantly shortened mean closure time compared with the C subgroup (p < 0.05).

CONCLUSIONS

This study shows the beneficial effect of bFGF on human traumatic large TMPs when applied after the 3rd day post-injury had passed (i.e. during the proliferative stage of wound healing). The procedure can not only significantly shorten closure time but can also reduce both the clinical administration duration and occurrence of side-effects associated with bFGF.

Effects of basic fibroblast growth factor dose on traumatic tympanic membrane perforation

OBJECTIVE

To compare the healing outcomes of higher and lower doses of basic fibroblast growth factor (bFGF) on human traumatic tympanic membrane perforation (TMP).

STUDY DESIGN

Prospective clinical study.

METHODS

All patients with traumatic TMP were treated by direct application of bFGF, and were sequentially allocated into one of two groups: lower-dose group (2-3 drops of bFGF solution daily, approximately 0.1-0.15 mL) and higher-dose group (5-6 drops of bFGF solution daily, approximately 0.25-0.3 mL). The results of closure rate, closure time, and rate of otorrhea between the higher- and lower-dose groups were compared at 3 months.

RESULTS

In total, 126 patients were included in this study. The higher-dose group showed significantly improved purulent otorrhea rate compared with the lower-dose group (p < 0.01) for perforations of the same size, although the closure rate of the middle-sized perforations did not differ significantly between higher- and lower-dose groups (p > 0.05). However, the lower-dose group had a significantly shorter closure time of 5 d compared with the higher-dose group (p < 0.05). In addition, although the lower-dose group showed shorter healing times (about 3 d) compared to the higher-dose group for large-sized perforations, the dosage of bFGF did not significantly affect the large-sized perforation closure rate (p > 0.05) or closure time (p > 0.05). Nine large-sized perforations with secondary purulent otorrhea achieved complete closure, with closure times of 7-25 (14.2 ± 5.8) d.

CONCLUSION

This study suggested that continued daily application of a lower dose of bFGF not only shortens the closure time of human traumatic TMP but also avoids secondary purulent otorrhea.

Healing outcomes of large (>50%) traumatic membrane perforations with inverted edges following no intervention, edge approximation and fibroblast growth factor application; a sequential allocation, three-armed trial

OBJECTIVE

The goal of this study was to evaluate the effects of perforation edge approximation and direct application of basic fibroblast growth factor (bFGF) each alone on the healing of large traumatic tympanic membrane perforations with inverted edges in humans.

STUDY DESIGN

Prospective, sequential allocation, three-armed, controlled clinical study.

SETTING

University-affiliated teaching hospital.

PARTICIPANTS

Fifty-eight patients with large traumatic tympanic membrane perforations (i.e. affecting >50% of the surface area) with inverted edges were recruited. They were sequentially allocated to three groups: no intervention (n = 18), edge approximation alone (n = 20) and direct application of bFGF (n = 20). Otoscopy were performed before the treatment and at follow-up visits.

MAIN OUTCOME MEASURES

The closure rate, closure time and rate of otorrhoea.

RESULTS

Application of bFGF yielded a significantly higher average rate of perforation closure (100%) than edge approximation (60%) and no intervention (56%) (P < 0.05). It also significantly shortened the average closure time (12.4 ± 3.6 days) as compared to edge approximation (46.3 ± 8.7 days) and no intervention control (48.2 ± 5.3 days) (P < 0.05). Purulent otorrhoea was observed in none of the three groups.

CONCLUSION

Edge approximation of inverted edges has little benefit in improving the healing outcome of large traumatic tympanic membrane perforations and thus is not an ideal treatment option for large traumatic tympanic membrane perforations. Application of bFGF materially improves the closure rate of large traumatic tympanic membrane perforations and significantly shortens the closure time.

Healing large traumatic eardrum perforations in humans using fibroblast growth factor applied directly or via gelfoam

OBJECTIVE

The goal of this study was to evaluate the effects of conservative treatment and fibroblast growth factor (FGF) applied directly or via Gelfoam on the healing of large traumatic tympanic membrane perforations (TMPs) in humans.

STUDY DESIGN

Prospective, randomized, controlled trial.

METHODS

A randomized prospective analysis was performed between February 2009 and January 2011 for the treatment of traumatic TMPs in humans that affected greater than 50% of the TM. The closure rate, closure time, hearing gain, and rate of otorrhea were compared among the direct application of FGF, FGF via Gelfoam, and conservative treatment.

RESULTS

A total of 94 patients were analyzed. The closure rates of large perforations in the direct FGF application, FGF via Gelfoam, and observation groups were 100%, 97%, and 55%, respectively. FGF-treated groups had significantly improved closure rates compared with the observation group (p < 0.05). However, the closure rate did not differ significantly between patients who received FGF only and those who received FGF via Gelfoam (p > 0.05). FGF-treated groups showed shorter mean closure times compared with the observation group (p < 0.05). However, the closure time did not differ significantly between FGF-treated groups (p > 0.05).All perforations were closed within 2 weeks, regardless of the presence of curled edges in the FGF-treated groups.