The Topical Effect of rhGDF-5 Embedded in a Collagen–Gelatin Scaffold for Accelerated Wound Healing

The application of exogenous growth factors such as the recombinant human growth and differentiation factor 5 (rhGDF-5) represents a major research topic with great potential for the treatment of complex wounds. In a randomized, controlled minipig study, the topical effect of rhGDF-5 on full-thickness skin defects was evaluated. A total of 60 deep dermal wounds were either treated with rhGDF-5 embedded in an innovative collagen scaffold or another commonly used collagen matrix or left untreated. Wound healing was analyzed by planimetric analysis to determine wound closure over time. After 21 days, the areas of the initial wounds were excised, and the newly formed tissue was examined histologically. In comparison to untreated wounds, all examined matrices accelerated dermal wound healing. The largest acceleration of wound healing was seen with the high-dose rhGDF-5-treated wounds, which, compared to the untreated wounds, accelerated wound healing by 2.58 days, improved the neoepidermal thickness by 32.40 µm, and increased the epidermal cell density by 44.88 cells. The innovative collagen scaffold delivered rhGDF-5 adequately, served as a template to guide proliferating and restructuring cells, and accelerated wound healing. Thus, this composite product offers a novel tool for developing effective wound dressings in regenerative medicine.

Human Sensory Neuron-like Cells and Glycated Collagen Matrix as a Model for the Screening of Analgesic Compounds

Increased collagen-derived advanced glycation end-products (AGEs) are consistently related to painful diseases, including osteoarthritis, diabetic neuropathy, and neurodegenerative disorders. We have recently developed a model combining a two-dimensional glycated extracellular matrix (ECM-GC) and primary dorsal root ganglion (DRG) that mimicked a pro-nociceptive microenvironment. However, culturing primary cells is still a challenge for large-scale screening studies. Here, we characterized a new model using ECM-GC as a stimulus for human sensory-like neurons differentiated from SH-SY5Y cell lines to screen for analgesic compounds. First, we confirmed that the differentiation process induces the expression of neuron markers (MAP2, RBFOX3 (NeuN), and TUBB3 (β-III tubulin), as well as sensory neuron markers critical for pain sensation (TRPV1, SCN9A (Nav1.7), SCN10A (Nav1.8), and SCN11A (Nav1.9). Next, we showed that ECM-GC increased c-Fos expression in human sensory-like neurons, which is suggestive of neuronal activation. In addition, ECM-GC upregulated the expression of critical genes involved in pain, including SCN9A and TACR1. Of interest, ECM-GC induced substance P release, a neuropeptide widely involved in neuroinflammation and pain. Finally, morphine, the prototype opiate, decreased ECM-GC-induced substance P release. Together, our results suggest that we established a functional model that can be useful as a platform for screening candidates for the management of painful conditions.

Root resorption in relation to a modified piezocision technique

ABSTRACT Objectives To evaluate root resorption of lower incisors and canines quantitatively in a group of patients who underwent orthodontic treatment with piezocision and/or a collagen reinforcement technique with a fully resorbable three-dimensional (3D) collagen xenograft matrix compared with a control group. Materials and Methods The study sample of this secondary analysis consisted of 32 periodontally healthy patients with angle Class I malocclusion or mild Class II or III malocclusion and moderate irregularity index scores who underwent orthodontic treatment and had before (T0) and after treatment (T1) cone-beam computed tomography scans. Root resorption of lower incisors and canines was assessed quantitatively in the following four groups: the control group received orthodontic treatment without piezocision, experimental group 1 received orthodontic treatment with piezocision, experimental group 2 received orthodontic treatment with piezocision and a 3D collagen matrix, and experimental group 3 received orthodontic treatment with a 3D collagen matrix. Results An overall statistically significant decrease in root length from T0 to T1 for all groups was observed (P < .05). However, there was no significant difference among the groups in the amount of root length decrease from T0 to T1. Conclusions Orthodontic treatment combined with piezocision does not increase the risk of root resorption of lower incisors and canines when compared with orthodontic treatment without acceleration techniques. More studies with larger samples should be undertaken to confirm these results.

Development of New Collagen/Clay Composite Biomaterials

The fabrication of collagen-based biomaterials for skin regeneration offers various challenges for tissue engineers. The purpose of this study was to obtain a novel series of composite biomaterials based on collagen and several types of clays. In order to investigate the influence of clay type on drug release behavior, the obtained collagen-based composite materials were further loaded with gentamicin. Physiochemical and biological analyses were performed to analyze the obtained nanocomposite materials after nanoclay embedding. Infrared spectra confirmed the inclusion of clay in the collagen polymeric matrix without any denaturation of triple helical conformation. All the composite samples revealed a slight change in the 2-theta values pointing toward a homogenous distribution of clay layers inside the collagen matrix with the obtaining of mainly intercalated collagen-clay structures, according X-ray diffraction analyses. The porosity of collagen/clay composite biomaterials varied depending on clay nanoparticles sort. Thermo-mechanical analyses indicated enhanced thermal and mechanical features for collagen composites as compared with neat type II collagen matrix. Biodegradation findings were supported by swelling studies, which indicated a more crosslinked structure due additional H bonding brought on by nanoclays. The biology tests demonstrated the influence of clay type on cellular viability but also on the antimicrobial behavior of composite scaffolds. All nanocomposite samples presented a delayed gentamicin release when compared with the collagen-gentamicin sample. The obtained results highlighted the importance of clay type selection as this affects the performances of the collagen-based composites as promising biomaterials for future applications in the biomedical field.

Optiminization of regeneration at the stages of soft tissue augmentation using a collagen matrix

Lack of adequate width and thickness of periodontal or peri-implant soft tissues can compromise the aesthetics, function or survival of teeth and dental implants. Biomaterials are widely used in dentistry to overcome the disadvantages of autogenous tissue transplantation. The advantage of using biomaterials is that there is no need for re-surgery and that they are available in large quantities. The most widely used biomaterial for soft tissue augmentation is collagen, as it is believed to best mimic the natural cellular environment of the extracellular matrix, although other biomaterials are also candidates for soft tissue regeneration. Collagen matrices differ in composition, three-dimensional structure, elasticity and mechanical stability. Aim. is to review the literature on the optimization of regeneration at the stages of soft tissue augmentation using a collagen matrix.

Effects of Remineralizing Agents Based on Calcium Phosphate, Sodium Phosphate, or Sodium Fluoride on Eroded Cervical Dentin

SUMMARY Objectives: To evaluate the effect of remineralizing agents on collagen matrix pattern, precipitate formation, and dentinal tubule obliteration in eroded cervical dentin. Methods and Materials: One hundred bovine cervical dentin specimens were previously eroded (0.6% hydrochloric acid, pH 2.3, 5 minutes) and then randomized into five groups (n=20): G1, control (without treatment); G2, Desensibilize Nano P (FGM); G3, MI Paste Plus (Recaldent); G4, Regenerate (NR-5); and G5, Desensibilize KF 2% (FGM). These treatments were applied in four sessions with 7-day intervals. During this period, the samples were subjected to an erosive challenge with orange juice (pH 3.8, 5 minutes). The specimens were analyzed by polarized light microscopy with picrosirius red staining, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Results: The G3 showed a higher concentration of type I collagen than G2 and G5 (p<0.05). The G3 showed greater formation of surface precipitates than that of G1 and G5 (p<0.05). In addition, G4 and G5 showed a greater number of open dentinal tubules than that of G3 (p<0.05). Conclusions: Calcium phosphate-based remineralizing agents have shown to be a promising alternative treatment for preventing deleterious effects on the eroded dentin collagen matrix. In addition, they promoted precipitate formation and dentinal tubule obliteration on the eroded dentin.

Second Generation of Tissue-Engineered Ligament Substitutes for Torn ACL Replacement: Adaptations for Clinical Applications

The anterior cruciate ligament (ACL) of the knee joint is one of the strongest ligaments of the body and is often the target of traumatic injuries. Unfortunately, its healing potential is limited, and the surgical options for its replacement are frequently associated with clinical issues. A bioengineered ACL (bACL) was developed using a collagen matrix, seeded with autologous cells and successfully grafted and integrated into goat knee joints. We hypothesize that, in order to reduce the cost and simplify the model, an acellular bACL can be used as a substitute for a torn ACL, and bone plugs can be replaced by endobuttons to fix the bACL in situ. First, acellular bACLs were successfully grafted in the goat model with 18% recovery of ultimate tensile strength 6 months after implantation (94 N/mm2 vs. 520). Second, a bACL with endobuttons was produced and tested in an exvivo bovine knee model. The natural collagen scaffold of the bACL contributes to supporting host cell migration, growth and differentiation in situ post-implantation. Bone plugs were replaced by endobuttons to design a second generation of bACLs that offer more versatility as biocompatible grafts for torn ACL replacement in humans. A robust collagen bACL will allow solving therapeutic issues currently encountered by orthopedic surgeons such as donor-site morbidity, graft failure and post-traumatic osteoarthritis.

Aesthetic root coverage with acellular dermal matrix allograft: a shield for gingival recession

Awareness about root coverage is increasing in day-to-day clinical practice. Patients are more motivated and concerned about aesthetics nowadays along with the issues of sensitivity of teeth. The conventional flap designs and techniques including lateral sliding flaps, coronally advanced flap, subepithelial connective tissue grafts and free gingival grafts are being adopted for root coverage. The newer material including resorbable and non-resorbable guided tissue regenerative membranes, amniotic membrane, platelet-rich fibrin membrane, enamel matrix derivative protein, xenogenic collagen matrix graft along with the soft tissue substitute like acellular dermal matrix allograft are also being used for recession coverage. The present case report describes a case of 22-year-old female patient with the chief complaint of denudation of gums exposing the root surface over the mandibular left central incisor. The soft tissue substitute acellular dermal matrix allograft was used for root coverage as the patient was not willing to procure an autogenous palatal graft. The results were satisfactory with complete root coverage.