The Preparation of Acellular Dermal Matrices by Freeze-Thawing and Ultrasonication Process and the Evaluation of Its Antigenicity

Regenerative effect of microcarrier form of acellular dermal matrix versus bone matrix bio-scaffolds loaded with adipose stem cells on rat bone defect

BACKGROUND

Bone defects lead to dramatic changes in the quality of life. Acellular dermal matrix (ADM) and decellularized bone matrix (DBM) are natural scaffolds for tissue regeneration. The microcarrier scaffolds enable better vascularization and cell proliferation. This study compared the effect of microcarrier forms of DBM and ADM-loaded with adipose stem cells (ASCs) in the repair of compact bone defect in-vivo.

METHODS

Fifty-four male rats were divided into 4 groups; (i) Group (Gp) I: sham control; (ii) GpII: underwent femur bone defect induction and left to heal spontaneously; (iii) GpIII (ADM-Gp): included 2 subgroups; IIIa and IIIb: the bone defects were filled with non-loaded ADM and ADM-loaded with ASCs, respectively; (iv) GpIV (DBM-Gp): included 2 subgroups; IVa and IVb: the bone defects were filled with non-loaded DBM and DBM-loaded with ASCs, respectively. Animals were euthanized after 1, 2 and 3 months and their femur sections were stained with H&E, Masson's trichrome and immunohistochemistry for CD31, osteopontin and osteocalcin.

RESULTS

Histological analysis illustrated limited bone regeneration in the cortical defect of GpII after 3 months. The histomorphometric analysis showed significant delayed mature collagen deposition as well as CD31, osteopontin and osteocalcin expression. Superior capacity of new bone regeneration was detected with bio-scaffold micro-carriers; loaded or non-loaded with ASCs. However, DBM-loaded with ASCs displayed enhanced regeneration properties confirmed by the apparently normal architecture of the new bone and accelerated expression of CD31, osteopontin and osteocalcin in the regenerated bone after 3 months.

CONCLUSIONS

We concluded that decellularized scaffolds significantly improved compact bone regeneration with superiority of ASCs seeded-bone scaffolds.

Biomedical Application of Decellularized Scaffolds

Tissue loss and end-stage organ failure are serious health problems across the world. Natural and synthetic polymer scaffold material based artificial organs play an important role in the field of tissue engineering and organ regeneration, but they are not from the body and may cause side effects such as rejection. In recent years, the biomimetic decellularized scaffold based materials have drawn great attention in the tissue engineering field for their good biocompatibility, easy modification, and excellent organism adaptability. Therefore, in this review, we comprehensively summarize the application of decellularized scaffolds in tissue engineering and biomedicine in recent years. The preparation methods, modification strategies, construction of artificial tissues, and application in biomedical applications are discussed. We hope that this review will provide a useful reference for research on decellularized scaffolds and promote their application tissue engineering.

Decellularized scaffold and its elicited immune response towards the host: the underlying mechanism and means of immunomodulatory modification

The immune response of the host towards a decellularized scaffold is complex. Not only can a number of immune cells influence this process, but also the characteristics, preparation and modification of the decellularized scaffold can significantly impact this reaction. Such factors can, together or alone, trigger immune cells to polarize towards either a pro-healing or pro-inflammatory direction. In this article, we have comprehensively reviewed factors which may influence the immune response of the host towards a decellularized scaffold, including the source of the biomaterial, biophysical properties or modifications of the scaffolds with bioactive peptides, drugs and cytokines. Furthermore, the underlying mechanism has also been recapitulated.

Decellularized xenografts in regenerative medicine: From processing to clinical application

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.

Comparative Study on Acellular Dermal Graft Versus Propylene Mesh Both Either Loaded or Unloaded with BM-MSCs in Healing of Skull Bone Defect in Rats: Histological and Immunohistochemical Study

Bone defect occurs as a consequence of many conditions. Diseased bones don’t heal properly and defects in face area need proper bone reconstruction to avoid psychological and social problems. Tissue engineering is an emerging new modality of treatment. We thought to study different methods to fill skull bone defect in rats in order to find the most safe and effective method. So, this study was designed to evaluate the efficacy of acellular dermal graft (ADM) versus propylene mesh both either loaded or unloaded with bone marrow derived mesenchymal stem cells (BM-MSCs) in healing of skull bone defect of a 5 mm diameter. The study included 36 adult male Wistar albino rats that were divided into three groups according to the way of filling skull bone defect. Group I: Ia (sham control), Ib (negative control). Group II: IIa (unseeded propylene), IIb (seeded propylene) and Group III: IIIa (unseeded ADM), IIIb (seeded ADM). The trephine operation was done on the left parietal bone. Specimens were collected four weeks postoperative and processed for H&E, osteopontin immunohistochemistry and scanning electron microscope. Morphometric and statistical analysis were also performed. After studying the results of the experiment, we found that propylene mesh and ADM were suitable scaffolds that could support new bone formation in clavarial bone defect. Healing of skull bone defect was better in rats that received seeded scaffolds more than rats with unseeded scaffolds. The seeded ADM showed significant increase in bone forming activity as confirmed by histomorphometric and statistical results.

Comparing the Outcome of Different Biologically Derived Acellular Dermal Matrices in Implant-based Immediate Breast Reconstruction: A Meta-analysis of the Literatures

Background:

Acellular dermal matrices (ADMs) have been used extensively in implant-based breast reconstruction. It was reported that due to the different sources and processing methods, the outcomes of ADMs in implant-based breast reconstructions are expected to differ. We designed this study to statistically analyze and discuss the outcome of 3 commonly used ADMs, Alloderm, Strattice, and Surgimend in implant-based breast reconstruction.

Methods:

Comprehensive review of the literatures searched on electronic databases was done to identify studies published between 2006 and 2017 comparing the outcome of ADMs. Pooled random effect estimates for each complication and 95% confidence interval (CI) were calculated. One-way analysis of variance and Bonferroni test were used to compare statistical significance between and within groups, respectively. Multiple linear regression was done to include confounding factors and R statistic program for forest plot.

Results:

Twenty-one studies met the inclusion with a total of 1,659, 999, and 912 breasts reconstructions in Alloderm, Strattice, and Surgimend, respectively. Seven complications extracted including major and minor infection, seroma, implant loss, hematoma, capsular contracture, and localized erythema. Pooled total complication rates were 23.82% (95% CI, 21.18–26.47%) in Strattice, 17.98% (95% CI, 15.49–20.47%) in Surgimend, 16.21% (95% CI, 14.44–17.99%) in Alloderm. Seroma rate was the highest in Strattice group (8.61%; 95% CI, 6.87–10.35%). There was no statistical significance between and within groups.

Conclusion:

Although Strattice exhibited a higher overall pooled complication rate compared with Alloderm and Surgimend, the incidence of individual complication varies between studies. A cost analysis of different ADMs may aid in choosing the type of ADMs to be used.

Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime

There are recent reports of hybrid tissue-fabric materials with good performance-high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue-fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat's body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone.