A Feasibility and Safety Study of a Novel Human Decellularized Dermal Matrix to Accelerate Healing of Neuropathic Diabetic Foot Ulcers in People With Type 1 and Type 2 Diabetes.

Objectives: The purpose of this study was to determine the feasibility and safety of a novel decellularized dermal matrix (DDM) for the treatment of chronic diabetic foot ulcers (DFUs).

Methods: An interventional, single-arm, prospective study of DDM for DFU treatment was conducted in 2 Canadian centres from July 1, 2016, to May 30, 2017. Individuals ≥18 years of age with an active DFU of ≥2 weeks and ulcer area ≥1 cm before debridement and who consented to participate were enrolled in this clinical trial.

Angiotensin II Type I Receptor Blockade Is Associated with Decreased Cutaneous Scar Formation in a Rat Model.

Background: Angiotensin II engagement of angiotensin II type 1 receptor (AT1R) is implicated in fibrogenesis, with AT1R blockers used clinically to attenuate cardiac and renal fibrosis. The authors tested the hypothesis that the AT1R blocker losartan could reduce postsurgical cutaneous scarring in rats.

Methods: Human dermal fibroblasts were treated with losartan and assessed for viability, contractile activity, migration, and profibrotic gene transcription by means of calcein, collagen gel, scratch, and quantitative reverse transcriptase polymerase chain reaction assays, respectively.

Precision cell delivery in biphasic polymer systems enhances growth of keratinocytes in culture and promotes their attachment on acellular dermal matrices.

Current approaches for precision deposition of cells are not optimized for moist environments or for substrates with complex surface topographic features, for example, the surface of dermal matrices and other biomaterials. To overcome these challenges, an approach is presented that utilizes cell confinement in phase-separating polymer solutions of polyethylene glycol and dextran to precisely deliver keratinocytes in well-defined colonies. Using this approach, keratinocyte colonies are produced with superior viability, proliferative capacity, and barrier formation compared with the same number of cells dispersedly seeded across substrate surfaces.

Efficient decellularization of rabbit trachea to generate a tissue engineering scaffold biomatrix.

Objectives: Most tracheal decellularization protocols are lengthy and can lead to reduced biomechanical stability. The objectives of this study were: 1) to generate a tracheal extracellular matrix scaffold using an efficient decellularization process and 2) to characterize the decellularized scaffold to assess its suitability for tissue engineering applications.

Methods: Twelve rabbit tracheae underwent a decellularization process that involved enzymatic-detergent treatments.

Development and characterization of decellularized human nasoseptal cartilage matrix for use in tissue engineering.

Objectives/hypothesis: Reconstruction of cartilage defects in the head and neck can require harvesting of autologous cartilage grafts, which can be associated with donor site morbidity. To overcome this limitation, tissue-engineering approaches may be used to generate cartilage grafts. The objective of this study was to decellularize and characterize human nasoseptal cartilage with the aim of generating a biological scaffold for cartilage tissue engineering.

Repair of tympanic membrane perforation using novel adjuvant therapies: a contemporary review of experimental and tissue engineering studies.

Objective: To perform a contemporary review of experimental studies to describe the effects of various novel adjuvant therapies in enhancing tympanic membrane (TM) perforation healing.

Methods: A PubMed search for articles from January 2000 to June 2012 related to TM perforation, along with the references of those articles, was performed. Inclusion and exclusion criteria were applied to all experimental studies assessing adjuvant therapies to TM healing.

Effect of basic fibroblast growth factor on the cellular repopulation of decellularized anterior cruciate ligament allografts.

The use of decellularized anterior cruciate ligament (ACL) allografts in ACL replacement surgery may allow for the native structure of the ligament to be retained, thereby recapturing the function of the ligament post-injury. Our previous work has focused on repopulating decellularized allograft ACL tissue with ACL fibroblasts in order to prevent destructive remodelling of the implanted tissue by extrinsic host cells. In this study, the use of basic fibroblast growth factor (bFGF) to improve the cellular repopulation of decellularized ACL tissue was assessed.

Matrix alteration and not residual sodium dodecyl sulfate cytotoxicity affects the cellular repopulation of a decellularized matrix.

It has been suggested that residual cytotoxic sodium dodecyl sulfate (SDS) is responsible for the low levels of cell in-growth observed in SDS decellularized tissues. To determine whether this is the case, we used 2 washing methods to remove residual SDS and extensive biochemical, mechanical, and structural analyses to determine the effects of SDS-based decellularization on porcine anterior cruciate ligament (ACL) tissue and its propensity for cellular repopulation. The level of residual SDS in decellularized tissue was reduced using 2 different washing techniques (pH = 9 buffer, 75% ethanol).

The effect of chemical modification of amino acid side-chains on collagen degradation by enzymes.

In this study, the effects of specific chemical modifications of amino acid side-chains on the in vitro enzyme degradation of type I collagen was studied. Two monofunctional epoxides of different size and chemistry were used to modify lysine and methylglyoxal was used to modify arginine. Lysine residues were modified using glycidol, a small hydrophilic reagent or n-butylglycidylether, a larger hydrophobic reagent.

Effect of extraction protocols and epidermal growth factor on the cellular repopulation of decellularized anterior cruciate ligament allografts.

We are developing a decellularized bone-anterior cruciate ligament (ACL)-bone allograft for treatment of ACL disruption in young or active patients. This study demonstrates the feasibility of seeding decellularized ACL tissue with primary ligament fibroblasts. Porcine ACLs were decellularized by one of three protocols, each differing only by the detergent/solvent used during the second wash (SDS, Triton-X, or TnBP).

Effectiveness of three extraction techniques in the development of a decellularized bone-anterior cruciate ligament-bone graft.

In this study, porcine bone-anterior cruciate ligament-bone (B-ACL-B) grafts were decellularized using one of three protocols incorporating surfactants lauryl sulfate (SDS), Triton X-100, and/or an organic solvent (tributyl phosphate (TnBP)). The effectiveness of Triton-SDS, Triton-Triton or Triton-TnBP treatments in removing cellular materials was determined and possible changes in biochemical composition and mechanical properties due to each treatment were investigated. Treatment with Triton-SDS was most effective at removing cell nuclei and intracellular protein (vimentin) from the ACL but affected both the collagen and glycosaminoglycan (GAG) components of the extracellular matrix while increasing the tensile stiffness of the ligament.

Modulation of collagen proteolysis by chemical modification of amino acid side-chains in acellularized arteries.

In this study, we have examined the effects of specific chemical modifications of amino acid side-chains on the in vitro degradation of "native" collagen obtained from acellular matrix (ACM)-processed arteries. Two monofunctional epoxides of different size and chemistry were used to modify lysine, with or without methylglyoxal modification of arginine. Biochemical, thermomechanical, tensile mechanical, and multi-enzymatic (collagenase, cathepsin B, acetyltrypsin, and trypsin) degradation analyses were used to determine the effects of modifications.

Control of pH alters the type of cross-linking produced by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) treatment of acellular matrix vascular grafts.

Carbodiimide cross-linking of bioprosthetic materials has been shown to provide tissue stabilization equivalent to that of glutaraldehyde cross-linking, but without the risk of the release of unreacted or depolymerized cytotoxic reagent after implantation. In this study, the effects of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) treatment on acellularized ovine carotid arteries were studied under two different pH conditions: (i) pH controlled at an optimal value of 5.5; and (ii) a simpler, but industrially significant, uncontrolled pH system.

Altered mechanical properties in aortic elastic tissue using glutaraldehyde/solvent solutions of various dielectric constant.

The extent to which elastic tissue can be crosslinked in aldehydes and the mechanism of such action is unresolved in the literature. We have used glutaraldehyde/solvent solutions of decreasing dielectric constant (phosphate buffer, methanol, 95% ethanol, n-propanol, n-butanol) to alter the mechanical properties of aortic elastic tissue obtained from autoclaved and CNBr-purified bovine aortae. Treated and untreated hoop samples were examined for stress-strain and stress relaxation behavior and for residual stress using opening angle experiments as per Fung.

Effect of applied uniaxial stress on rate and mechanical effects of cross-linking in tissue-derived biomaterials.

Conformational changes in collagen fibrils, and indeed the triple helix, can be produced by application of mechanical stress or strain. We have demonstrated that the rate of cross-linking in glutaraldehyde and epoxide homobifunctional reagents can be modulated by uniaxial stress (strain). Two poly(glycidyl ether) epoxides were used: Denacol EX-810 (a small bifunctional reagent), and Denacol EX-512 (a large polyfunctional reagent).

Solvent environment modulates effects of glutaraldehyde crosslinking on tissue-derived biomaterials.

Bioprosthetic materials utilized in the construction of heart valves and vascular grafts possess limited performance and viability in vivo. This is due (in part) to the failure of these materials to mimic the mechanical properties of the host tissue they replace. If bioprosthetic materials could be engineered to meet the mechanical performance required in vivo, the functional lifetime of implants would be increased.

[Electric dental care in the child with multiple disability (author's transl)].

Considering the benefits of toothbrushing in dental health, the superiority of the electric toothbrush over conventional toothbrushes is described. The various special effects of electric toothbrushing for the cerebral palsied and the epileptic child are set forth, as are the procedures to be observed in initial use. In the treatment of dysarthria, the electric toothbrush may moreover be helpful for desensitizing the mouth area.