Cellular Interaction of Human Skin Cells towards Natural Bioink via 3D-Bioprinting Technologies for Chronic Wound: A Comprehensive Review

Skin substitutes can provide a temporary or permanent treatment option for chronic wounds. The selection of skin substitutes depends on several factors, including the type of wound and its severity. Full-thickness skin grafts (SGs) require a well-vascularised bed and sometimes will lead to contraction and scarring formation. Besides, donor sites for full-thickness skin grafts are very limited if the wound area is big, and it has been proven to have the lowest survival rate compared to thick- and thin-split thickness. Tissue engineering technology has introduced new advanced strategies since the last decades to fabricate the composite scaffold via the 3D-bioprinting approach as a tissue replacement strategy. Considering the current global donor shortage for autologous split-thickness skin graft (ASSG), skin 3D-bioprinting has emerged as a potential alternative to replace the ASSG treatment. The three-dimensional (3D)-bioprinting technique yields scaffold fabrication with the combination of biomaterials and cells to form bioinks. Thus, the essential key factor for success in 3D-bioprinting is selecting and developing suitable bioinks to maintain the mechanisms of cellular activity. This crucial stage is vital to mimic the native extracellular matrix (ECM) for the sustainability of cell viability before tissue regeneration. This comprehensive review outlined the application of the 3D-bioprinting technique to develop skin tissue regeneration. The cell viability of human skin cells, dermal fibroblasts (DFs), and keratinocytes (KCs) during in vitro testing has been further discussed prior to in vivo application. It is essential to ensure the printed tissue/organ constantly allows cellular activities, including cell proliferation rate and migration capacity. Therefore, 3D-bioprinting plays a vital role in developing a complex skin tissue structure for tissue replacement approach in future precision medicine.

Complete chemical and structural characterization of selenium-incorporated hydroxyapatite

Hydroxyapatite (HAp) has long been used as synthetic bone tissue replacement material. Recent advances in this area have led to development of dual-functional bioceramics exhibiting high biocompability/osteoconductivity together with the therapeutic effect. Selenium, in that respect, is an effective therapeutic agent with promising antioxidant activity and anticancer effects. In this study, selenium-incorporated hydroxyapatite (HAp:Se) particles have been synthesized by modified aqueous precipitation method using calcium (Ca(NO3)2·4H2O) and phosphate ((NH4)2HPO4) salts and sodium selenite (Na2SeO3). The effects of selenium incorporation and post-synthesis calcination treatment (900–1100 °C) on physical, chemical properties and crystal structure of resultant HAp powders have been investigated. Complete chemical identification was performed with spectroscopical analyses including Fourier transform infrared and x-ray photoelectron spectroscopy to elucidate the mechanism and chemical nature of selenium incorporation in HAp. Meanwhile, detailed x-ray diffraction studies by Rietveld refinement have conducted to explain changes in the HAp crystal structure upon selenium incorporation.

Anti-Synthetase Syndrome Complicated by Pyogenic Myositis

Background: Anti-synthetase syndrome is a rare autoimmune disorder characterized by autoantibodies against aminoacyl-tRNA-synthetases. Inflammatory myopathy and interstitial lung disease could be present among other manifestations. Anti-Jo-1 is the most common antisynthetase antibody and is the most likely to present with the classic triad (interstitial lung disease, myositis, and arthritis) and have more muscle and joint involvement than patients with other antisynthetase antibodies. Case report: Here, we present a case of a 60-year-old female patient, with a previous diagnosis of myositis, secondary to the anti-synthetase syndrome, with a complication by pyogenic myositis. Conclusion: Diagnosis is made by a multidisciplinary approach, occasionally muscle and/or lung biopsy are needed. Imaging studies, Especially magnetic resonance imaging, based on findings such as muscle and fascial edema, and fatty tissue replacement, allow an optimal approach.

Evaluating Feasibility of Human Tissue Engineered Respiratory Epithelium Construct as a Potential Model for Tracheal Mucosal Reconstruction

The normal function of the airway epithelium is vital for the host’s well-being. Conditions that might compromise the structure and functionality of the airway epithelium include congenital tracheal anomalies, infection, trauma and post-intubation injuries. Recently, the onset of COVID-19 and its complications in managing respiratory failure further intensified the need for tracheal tissue replacement. Thus far, plenty of naturally derived, synthetic or allogeneic materials have been studied for their applicability in tracheal tissue replacement. However, a reliable tracheal replacement material is missing. Therefore, this study used a tissue engineering approach for constructing tracheal tissue. Human respiratory epithelial cells (RECs) were isolated from nasal turbinate, and the cells were incorporated into a calcium chloride-polymerized human blood plasma to form a human tissue respiratory epithelial construct (HTREC). The quality of HTREC in vitro, focusing on the cellular proliferation, differentiation and distribution of the RECs, was examined using histological, gene expression and immunocytochemical analysis. Histological analysis showed a homogenous distribution of RECs within the HTREC, with increased proliferation of the residing RECs within 4 days of investigation. Gene expression analysis revealed a significant increase (p < 0.05) in gene expression level of proliferative and respiratory epithelial-specific markers Ki67 and MUC5B, respectively, within 4 days of investigation. Immunohistochemical analysis also confirmed the expression of Ki67 and MUC5AC markers in residing RECs within the HTREC. The findings show that calcium chloride-polymerized human blood plasma is a suitable material, which supports viability, proliferation and mucin secreting phenotype of RECs, and this suggests that HTREC can be a potential candidate for respiratory epithelial tissue reconstruction.

Standardized Anatomic and Regenerative Facial Fat Grafting: Objective Photometric Evaluation From 1-19 Months After Injectable Tissue Replacement and Regeneration (ITR2)

Background A standardized technique for facial fat grafting, Injectable Tissue Replacement and Regeneration (ITR 2), was developed to address both anatomic volume losses in superficial and deep fat compartments as well as skin aging, incorporating newer regenerative approaches. Objectives The authors sought to track the short and long terms effects of a new standardized technique for facial fat grafting in the midfacial zone across a 19-month time period. Methods Twenty-nine female were analyzed for mid-facial volume changes after autologous fat transfer with ITR 2. Across 19 months, volumes were evaluated using the Vectra XT 3D Imaging System to calculate differences between a predefined, 3-dimensional mid-facial zone measured preoperatively and serially after fat grafting with novel approach using varying fat parcel sizes. Results Patient data was analyzed collectively as well as separately by age (&lt; and &gt; 55 years). Collective analysis revealed a trend of initial volume loss within the first 1-7 months followed by an increase within the 8–19-month range, averaging 56.6% postoperative gain and ending at an average of 52.3% gain in volume by 14-19 months. A similar trend was observed for patients &lt;55 years of age, but to a greater extent, with a 54.1% average postoperative gain and final average of 75.2%. Conversely, patients above 55 years of age revealed a linear decay beginning at 60.6% and steadily declining to 29.5%. Multiple regression analysis revealed no statistically significant influence of weight change during the study duration. Conclusions Preliminary evidence shows a dynamic change in facial volume, with an initial decrease in facial volume followed by a rebound effect that demonstrated improvement of facial volume regardless of patient weight change or amount of fat injected 19 months after treatment. Volume improvement occurred to a greater extent in patients under 55 years old, whereas in patients older than 55 volume gradually decreased. To our knowledge, this study represents the first time that progressive improvement in facial volume has been shown 19 months after treatment with a new standardized technique of fat grafting.