New approach of bone marrow-derived mesenchymal stem cells and human amniotic epithelial cells applications in accelerating wound healing of irradiated albino rats

Design and evaluation of a bilayered dermal/hypodermal 3D model using a biomimetic hydrogel formulation

Due to the limitations of the current skin wound treatments, it is highly valuable to have a wound healing formulation that mimics the extracellular matrix (ECM) and mechanical properties of natural skin tissue. Here, a novel biomimetic hydrogel formulation has been developed based on a mixture of Agarose-Collagen Type I (AC) combined with skin ECM-related components: Dermatan sulfate (DS), Hyaluronic acid (HA), and Elastin (EL) for its application in skin tissue engineering (TE). Different formulations were designed by combining AC hydrogels with DS, HA, and EL. Cell viability, hemocompatibility, physicochemical, mechanical, and wound healing properties were investigated. Finally, a bilayered hydrogel loaded with fibroblasts and mesenchymal stromal cells was developed using the Ag-Col I-DS-HA-EL (ACDHE) formulation. The ACDHE hydrogel displayed the best in vitro results and acceptable physicochemical properties. Also, it behaved mechanically close to human native skin and exhibited good cytocompatibility. Environmental scanning electron microscopy (ESEM) analysis revealed a porous microstructure that allows the maintenance of cell growth and ECM-like structure production. These findings demonstrate the potential of the ACDHE hydrogel formulation for applications such as an injectable hydrogel or a bioink to create cell-laden structures for skin TE.

Evaluation of the Number of Follow-up Surgical Procedures and Time Required for Delayed Breast Reconstruction by Clinical Risk Factors, Type of Oncological Therapy, and Reconstruction Approach

BACKGROUND

Breast reconstructive surgery is often a multistage process. The aim was to understand which factors might increase the number of follow-up surgeries and the length of time required to complete the reconstruction process.

METHODS

A cross-sectional analysis was performed. Clinical data of 110 patients who underwent delayed postmastectomy breast reconstruction with a 5-year examination period were reviewed retrospectively. Impact of clinical risk factors, oncological therapy, and reconstruction approach on the number of surgeries and the length of required time was analyzed. Mann-Whitney U test and Kruskal-Wallis rank sum test were used.

RESULTS

In patients undergoing perioperative hormone therapy, an average of 2.9 surgeries and length of 20.2 months were required compared to 2.3 surgeries and 14.0 months in patients without hormone therapy (P = 0.003; P = 0.005). Previous abdominal surgery was associated with an increased number of breast reconstruction stages of 3.1 per patient (P = 0.056) and a longer reconstruction time of 23.0 months (P = 0.050). Patients undergoing nipple reconstruction or implant revision required an increased number of surgeries (P < 0.001; P = 0.012) and a longer reconstruction time (P = 0.002; P < 0.001). Contralateral breast surgery and flap revision were associated only with an increased number of surgeries (P < 0.001; P < 0.001).

CONCLUSION

Perioperative hormone therapy was associated with a significantly higher number of surgeries and duration of time required to complete the reconstruction process. The highest increase in the number of surgeries was in patients with flap revision including anastomosis revision and necrectomy.

LEVEL OF EVIDENCE IV

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Corneal stromal mesenchymal stem cells: reconstructing a bioactive cornea and repairing the corneal limbus and stromal microenvironment

Corneal stroma-derived mesenchymal stem cells (CS-MSCs) are mainly distributed in the anterior part of the corneal stroma near the corneal limbal stem cells (LSCs). CS-MSCs are stem cells with self-renewal and multidirectional differentiation potential. A large amount of data confirmed that CS-MSCs can be induced to differentiate into functional keratocytes in vitro, which is the motive force for maintaining corneal transparency and producing a normal corneal stroma. CS-MSCs are also an important component of the limbal microenvironment. Furthermore, they are of great significance in the reconstruction of ocular surface tissue and tissue engineering for active biocornea construction. In this paper, the localization and biological characteristics of CS-MSCs, the use of CS-MSCs to reconstruct a tissue-engineered active biocornea, and the repair of the limbal and matrix microenvironment by CS-MSCs are reviewed, and their application prospects are discussed.

Therapeutic effect of adipose-derived mesenchymal stem cells (ASCs) on radiation-induced skin damage in rats

Background

Radiation-induced skin injury remains a serious concern, which may limit the duration and dose of radiation treatment. The concept that stem cell injection may reduce tissue injury or assist its recovery after radiation has been recently argued. Herein, we examined the effect of adipose-derived mesenchymal stem cells (ASCs) on radiation-induced skin damage in rats.

Methods

This study is an experimental case control study. ASCs were isolated from peri uterine fat tissue of the rats. Then the rats received a 30 Gy single dose radiation to their buttocks skin using gamma radiation. Next day stem cells were transplanted subcutaneously in 16 rats as the case group. A group of 16 rats was considered as control group with radiation but no transplantation of stem cells. Then rats were examined and observed by macroscopic analysis and phenotypic scores during 4 weeks of follow up.

Results

The wound size in control group was significantly higher than case group in the second, third and fourth weeks of evaluation (P<0.05). There was no significant difference in skin lesion severity, pathological factors, and the onset of recovery signs between two groups (P>0.05).

Conclusions

It seems that using ASCs alone has not profound effects on reducing radiation-induced cutaneous complications, while combination of these cells with growth factors may produce more promising results.

Treatment of Full-Thickness Skin Wounds with Blood-Derived CD34+ Precursor Cells Enhances Healing with Hair Follicle Regeneration

Objective: Epidermal CD34⁺ stem cells located in the hair follicle (HF) bulge area are capable of inducing HF neogenesis and enhancing wound healing after transplantation. In this study, we observed CD34⁺ cells derived from blood directly participate in dermal regeneration during full-thickness excisional wound healing. Approach: We isolated and in vitro expanded a subset of hematopoietic stem cell (HSC)-like precursor cells from the peripheral blood of adult mice with the surface markers: CD34⁺, leucine rich repeat containing G protein-coupled receptor 5 (LGR5)⁺, CD44⁺, c-kit⁺, lineage negative (lin^-), and E-cadherin^-. These blood-derived precursor cells (BDPCs), can be further differentiated into epithelial-like cells (eBDPCs) and secret fibroblast growth factor 9 (Fgf9) protein. Result: When transplanted into full-thickness skin wounds, eBDPC treatment produced accelerated healing and enhanced skin structure regeneration with less dermal scar formation. Also, HF neogenesis (HFN) was observed with incorporation of labeled BDPCs in the wound area. Innovation:Nondermal-derived CD34⁺ cells (BDPCs) from the adult unmobilized peripheral blood are capable of in vitro expansion and differentiation.Successful establishment of an in vitro technical platform for BDPCs expansion and differentiation.The in vitro expanded and differentiated epithelial-like cells (eBDPCs) enhance wound healing and directly contribute to skin regeneration and HFN. Conclusion: BDPCs isolated and expanded from adult peripheral blood may provide a possible new cell-based treatment strategy for HF neogenesis and skin wound regeneration.

3D bioprinting and in vitro study of bilayered membranous construct with human cells-laden alginate/gelatin composite hydrogels

Extrusion-based 3D bioprinting of cell-laden hydrogels is a potential technology for regenerative medicine, which enables the fabrication of constructs with spatially defined cell distribution. However, the limited assessment of rheological behaviors of hydrogel before printing is still a major issue for the advancement of 3D bioprinting. In this work, we systematically investigated the rheological behaviors (i.e. viscosity, storage modulus (G'), and loss modulus (G")) of alginate/gelatin composite hydrogels first for 3D printing complex constructs. The rheological studies revealed that viscosity of alginate/gelatin hydrogels is temperature-dependent and shear thinning. Sol-gel transition (intersection of G' and G") study provided indication for printing temperature, which are in the range of 18.8 °C (H2/7.5) to 24.5 °C (H2/24.5). The alginate (2 wt%) /gelatin (15 wt%) composite hydrogel sample was chosen to print the constructs and subsequent bioprinting. Complex constructs (i.e. nose and ear) were obtained with high printing resolution (151 ± 13.04 μm) in a low temperature (4 °C) chamber and crosslinking with 2 wt% CaCl₂ subsequently without extra supports. Human amniotic epithelial cells (AECs) showed superior potential to differentiate into epithelial cells, while Wharton's jelly derived mesenchymal stem cells (WJMSCs) showed a superior angiogenic potential and fibroblastic phenotype. For the in vitro study, AECs and WJMSCs as seed cells, encapsulated in alginate/gelatin composite hydrogels, were bioprinted to form biomimetic bilayered membranous construct. High cell viability (> 95%) were observed up to 6 days after printing. The presented 3D bioprinting of human AECs and WJMSCs-laden alginate/gelatin composite hydrogels provides promising potentials for future skin tissue engineering.

ENA-78 Is a Novel Predictor of Wound Healing in Patients with Diabetic Foot Ulcers

OBJECTIVES

Chronic foot ulceration is a severe complication of diabetes, driving morbidity and mortality. The aim of our study was to identify novel biomarkers of impaired wound healing in diabetic foot ulcers.

METHODS

109 patients with neuropathic diabetic foot ulcers and 30 burn victims otherwise healthy participated. Antibody-coated glass slide arrays were used to determine the levels of 80 human cytokines in pooled plasma or pooled wound exudate of diabetic foot ulcers with rapidly healing (RH, n = 12) and matched nonhealing (NH, n = 12) patients. Potential biomarkers were confirmed in an independent cohort by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Protein array profiling identified 27 proteins or 15 proteins significantly altered in protein profiling of pooled plasma or pooled wound exudate of 12 RH patients compared with 12 matched NH patients, respectively. In an independent cohort, quantitative ELISA validation confirmed a decrease in MCP-2 and ENA-78 levels in NH patients versus RH patients or burn victims. After adjusting for the traditional risk factors (sex, age, body mass index, fasting plasma glucose, ulcer area, HbA1C, diabetes duration, hyperlipidemia, and antibiotic therapy), only wound exudate level of ENA-78 remained having a significant association with an increased odds ratio (OR) for wound healing by binary logistic regression analysis (P < 0.05).

CONCLUSION

Decreased wound exudate ENA-78 was independently associated with wound healing of patients with diabetic foot. Exudate ENA-78 level is implicated as a novel predictor of wound healing in patients with diabetic foot ulcers.