Application of hyperdry amniotic membrane patches without fibrin glue over the bony surface of mastoid cavities in canal wall down tympanoplasty

Effect of hyperdry amniotic membrane in preventing tendon adhesion in a rabbit model

BACKGROUND

No anti-adhesive materials are currently in clinical use for orthopaedic surgery. We developed a hyperdry amniotic membrane (HD-AM) for easy storage and transplantation as amniotic membrane. The purpose of this study was to examine the application of HD-AM to reduce peritendinous adhesions without impairing tendon healing.

METHODS

We randomly divided 3 digits (2nd, 3rd, and 4th digits) from each rabbit into three groups: a tendon repair group; a tendon repair with HD-AM group (HD-AM group); and a control group (cast only). The effects of HD-AM on peritendinous adhesions and tendon healing were examined using microscopic, histological, and mechanical analyses in a rabbit flexor digitorum profundus tendon model.

RESULTS

Adhesions on macroscopic evaluation of the tendon repair site were significantly smaller in the HD-AM group than in the tendon repair group. Little adhesion formation or foreign body reactions were seen by on histologic evaluation in the HD-AM group. Range of motion following tendon repair was significantly better in the HD-AM group than in the tendon repair group. Maximal tensile strength required to pull the tendon from the site of adhesion was significantly smaller in the HD-AM group than in the tendon repair group. As for tendon repair site, no significant difference was seen between the tendon repair and HD-AM groups.

CONCLUSIONS

HD-AM prevented peritendinous adhesion macroscopically, pathologically, and mechanically without impairing the sutured tendon. HD-AM has already been clinically applied in neurosurgery, ophthalmology, and otolaryngology, and clinical application as an anti-adhesive materials may be achieved in the future.

Epithelial defect repair in the auricle and auditory meatus by grafting with cultured adipose-derived mesenchymal stem cell aggregate-extracellular matrix

Background:

Several patients experience persistent otorrhea after a flawless surgical procedure because of insufficient epithelial healing. Several efforts, such as autologous tissue allograft and xenograft, have been made to halt otorrhea. However, a stable technology to induce temporal epithelial repair is yet to be established. Therefore, this study aims to investigate whether implantation of seeding adipose-derived mesenchymal stem cell (ADMSC) aggregates on extracellular matrix (ECM; herein, ADMSC aggregate-ECM) into damaged skin wound promotes skin regeneration.

Methods:

ADMSC aggregate-ECM was prepared using a previously described procedure that isolated ADMSCs from rabbits and applied to the auricle and auditory meatus wound beds of New Zealand white rabbits. Wound healing was assessed by general observation and hematoxylin and eosin (H&E) staining. Secretion of growth factor of the tissue was evaluated by western blotting. Two other groups, namely, ECM and control, were used. Comparisons of three groups were conducted by one-way analysis of variance analysis.

Results:

ADMSCs adhered tightly to the ECM and quickly formed cell sheets. At 2 weeks, general observation and H&E staining indicated that the wound healing rates in the ADMSC aggregate-ECM (69.02 ± 6.36%) and ECM (59.32 ± 4.10%) groups were higher than that in the control group (43.74 ± 12.15%; P = 0.005, P < 0.001, respectively) in ear auricle excisional wounds. At 7 weeks, The scar elevation index was evidently reduced in the ADMSC aggregate-ECM (2.08 ± 0.87) and ECM (2.31 ± 0.33) groups compared with the control group (4.06 ± 0.45; P < 0.001, P < 0.001, respectively). In addition, the scar elevation index of the ADMSC aggregate-ECM group reached the lowest rate 4 weeks in advance. In auditory meatus excisional wounds, the ADMSC aggregate-ECM group had the largest range of normal skin-like structure at 4 weeks. The ADMSC aggregate–ECM and ECM groups secreted increased amounts of growth factors that contributed to skin regeneration at weeks 1 and 2, respectively.

Conclusions:

ADMSC aggregate-ECM and ECM are effective repair materials for wound healing, especially ADMSC aggregate-ECM. This approach will provide a meaningful experimental basis for mastoid epithelium repair in subsequent clinical trials.

Human Amniotic Membrane: A Versatile Scaffold for Tissue Engineering

The human amniotic membrane (hAM) is a collagen-based extracellular matrix derived from the human placenta. It is a readily available, inexpensive, and naturally biocompatible material. Over the past decade, the development of tissue engineering and regenerative medicine, along with new decellularization protocols, has recast this simple biomaterial as a tunable matrix for cellularized tissue engineered constructs. Thanks to its biocompatibility, decellularized hAM is now commonly used in a broad range of medical fields. New preparation techniques and composite scaffold strategies have also emerged as ways to tune the properties of this scaffold. The current state of understanding about the hAM as a biomaterial is summarized in this review. We examine the processing techniques available for the hAM, addressing their effect on the mechanical properties, biodegradation, and cellular response of processed scaffolds. The latest in vitro applications, in vivo studies, clinical trials, and commercially available products based on the hAM are reported, organized by medical field. We also look at the possible alterations to the hAM to tune its properties, either through composite materials incorporating decellularized hAM, chemical cross-linking, or innovative layering and tissue preparation strategies. Overall, this review compiles the current literature about the myriad capabilities of the human amniotic membrane, providing a much-needed update on this biomaterial.