Engineering Bioactive Scaffolds for Skin Regeneration.

Large skin wounds pose a major clinical challenge. Scarcity of donor site and postsurgical scarring contribute to the incomplete or partial loss of function and aesthetic concerns in skin wound patients. Currently, a wide variety of skin grafts are being applied in clinical settings. Scaffolds are used to overcome the issues related to the misaligned architecture of the repaired skin tissues. The current review summarizes the contribution of biomaterials to wound healing and skin regeneration and addresses the existing limitations in skin grafting. Then, the clinically approved biologic and synthetic skin substitutes are extensively reviewed. Next, the techniques for modification of skin grafts aiming for enhanced tissue regeneration are outlined, and a summary of different growth factor delivery systems using biomaterials is presented. Considering the significant progress in biomaterial science and manufacturing technologies, the idea of biomaterial-based skin grafts with the ability for scarless wound healing and reconstructing full skin organ is more achievable than ever.

Aspergillus coinfection among patients with pulmonary tuberculosis in Asia and Africa countries; A systematic review and meta-analysis of cross-sectional studies.

Progress of the disease and prolonged treatment with antibiotics or immunosuppressive agents makes tuberculosis patients susceptible to fungal infections. This study aimed to determine the prevalence of pulmonary Aspergillus coinfection among patients with pulmonary tuberculosis in Asia and Africa. The present review of cross-sectional studies was conducted on the prevalence of pulmonary Aspergillus coinfection among patients with pulmonary tuberculosis according to the PRISMA Protocol. Literatures published online in English from January 2001 to March 2019 via key databases such as Web of Science, MEDLINE, PubMed, Scopus, and Cochrane Library were searched. The used MeSH and non-MeSH keywords were; "pulmonary fungal", "pulmonary coinfection", OR "Pulmonary mycosis", "pulmonary fungal infections/agents", OR "Polymicrobial infection", OR "Secondary infection", OR "Mixed infections", "pulmonary aspergillosis", "fungi coinfection", "Fungal co-colonization", AND "pulmonary tuberculosis", OR "pulmonary TB", AND "Asia" AND "Africa". Finally, data analyzed using Comprehensive Meta-Analysis software (CMA). The combined Aspergillus coinfection among patients with pulmonary tuberculosis was 15.4% (95% CI: 11.4-20.5), Q = 105.8 and Z = 9.57 in Asia and Africa. The most frequency of Aspergillus spp. was related to A. fumigatus with a combined prevalence of 57.6%. Most of the studies included in the present review showed a higher Aspergillus coinfection in the age group of 40 years and higher. Also, the existence of a correlation between increasing age and Aspergillus coinfection was reported (p < 0.05). The present review showed a high combined Aspergillus coinfection among patients with pulmonary tuberculosis in Asia and Africa. Also, amongst the Aspergillus spp., the most frequent was related to A. fumigatus.

The interventional relationship between frequent fish consumption and depression symptoms in aging adults: a randomized controlled trial.

OBJECTIVE: The present investigation was intended to test the hypothesis that the elderly provided with the frequent consumption of fishes marinated in essential oil of Perilla frutescens (EOPF) or not would experience fewer depressive symptoms after 6 months. METHODS: A total of 180 participants were recruited from Sina Hospital, Mashhad, Iran, who were diagnosed with depression based on Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision and Beck Depression Inventory. Participants (n = 180) were randomly assigned in a 1:1:1 ratio to Groups A, B, and C. The last two were provided with an instruction to consume Caspian white fish marinated in the presence or absence of EOPF (434 g each week or four meals per week). Group A served as the control with the common diet. The outcome measures were performed using the Beck Depression Inventory and the General Health Questionnaire. RESULTS: There were no statistically significant differences in depressive symptom scores between groups with frequent fish consumption as compared with the control (p > 0.05). Yet adjustment for covariates showed that there was a significant reduction in depression among them (p < 0.05). Moreover, consumption of fish and EOPF was associated with more considerable improvements than Groups A and B (p < 0.05). CONCLUSIONS: It could be concluded that high intakes of unsaturated fatty acids can afford to diminish likelihood of late-life depression. Copyright © 2017 John Wiley & Sons, Ltd.

Vascularization of cutaneous wounds by stem cells.

Differentiated skin cells have limited self-renewal capacity; thus, the application of stem/progenitor cells, adult or induced stem cells, has attracted much attention for wound healing applications. Upon skin injury, vascularization, known as a highly dynamic process, occurs with the contribution of cells, the extracellular matrix, and relevant growth factors. Considering the importance of this process in tissue regeneration, several strategies have been proposed to enhance angiogenesis and accelerate wound healing. Previous studies report the effectiveness of stem/progenitor cells in skin wound healing by facilitating the vascularization process. This chapter reviews and highlights some of the key and recent investigations on application of stem/progenitor cells to induce skin revascularization after trauma.

Convergence of Biofabrication Technologies and Cell Therapies for Wound Healing.

BACKGROUND: Cell therapy holds great promise for cutaneous wound treatment but presents practical and clinical challenges, mainly related to the lack of a supportive and inductive microenvironment for cells after transplantation. Main: This review delineates the challenges and opportunities in cell therapies for acute and chronic wounds and highlights the contribution of biofabricated matrices to skin reconstruction. The complexity of the wound healing process necessitates the development of matrices with properties comparable to the extracellular matrix in the skin for their structure and composition. Over recent years, emerging biofabrication technologies have shown a capacity for creating complex matrices. In cell therapy, multifunctional material-based matrices have benefits in enhancing cell retention and survival, reducing healing time, and preventing infection and cell transplant rejection. Additionally, they can improve the efficacy of cell therapy, owing to their potential to modulate cell behaviors and regulate spatiotemporal patterns of wound healing. CONCLUSION: The ongoing development of biofabrication technologies promises to deliver material-based matrices that are rich in supportive, phenotype patterning cell niches and are robust enough to provide physical protection for the cells during implantation.

Biofabrication of Human Skin with Its Appendages.

Much effort has been made to generate human skin organ in the laboratory. Yet, the current models are limited due to the lack of many critical biological and structural features of the skin. Importantly, these in vitro models lack appendages and fail to recapitulate the whole human skin construction. Thus, engineering a human skin with the capacity to generate all components, including appendages, is a major challenge. This review intends to provide an update on the recent efforts underway to regenerate appendage-bearing skin organs based on scaffold-free and scaffold-based bioengineering approaches. Although the mouse skin equivalents containing hair follicles, sebaceous glands, and sweat glands have been established in vitro, there has been limited success in humans. A combination of biofabricated matrices and cell aggregates, such as organoids, can pave the way for generating skin substitutes with human-like biological, structural, and physical features. Accordingly, the formation of human skin organoids and reconstruction of vascularized skin equipped with immune cells prompt calls for more scientific research. The generation of appendage-bearing skin substitutes can be applied in practice for wound healing, hair restoration, and scar treatment.

Strategies to Induce Blood Vessel Ingrowth into Skin Grafts and Tissue-Engineered Substitutes.

Skin is a multilayer organ consisting of several tissues and appendages residing in a complex niche. Adequate and physiologically regulated vascularization is an absolute requirement for skin homeostasis, regeneration, and wound healing. The lack of vascular networks and ischemia results in delayed wound closure. In addition, vascularization is critical for the prolonged function and survival of skin grafts and tissue-engineered skin substitutes. This study highlights the clinical challenges associated with the limited vascularization in the cutaneous wounds. Then, we highlight the novel approaches for the development of vascular networks in the skin autografts, allografts, and artificial substitutes. Also, the future directions to overcome the existing vascularization complications in skin grafting and synthetic skin substitutes are presented. Statement of Significance Delayed closure of large dermal wounds, such as burn injuries, results from the lack of vascular networks and ischemia. The amount of blood supply in the skin graft is the primary factor determining the quality of the transplanted grafts. The current skin grafts and their fabrication methods lack the appropriate features that contribute to the vascularization and integration of the wound bed and graft and adherence to the skin layers. Therefore, the new generation of skin grafts should consider advanced technologies to induce vascularization and overcome current challenges.

Skin biomechanics: a potential therapeutic intervention target to reduce scarring.

Pathological scarring imposes a major clinical and social burden worldwide. Human cutaneous wounds are responsive to mechanical forces and convert mechanical cues to biochemical signals that eventually promote scarring. To understand the mechanotransduction pathways in cutaneous scarring and develop new mechanotherapy approaches to achieve optimal scarring, the current study highlights the mechanical behavior of unwounded and scarred skin as well as intra- and extracellular mechanisms behind keloid and hypertrophic scars. Additionally, the therapeutic interventions that promote optimal scar healing by mechanical means at the molecular, cellular or tissue level are extensively reviewed. The current literature highlights the significant role of fibroblasts in wound contraction and scar formation via differentiation into myofibroblasts. Thus, understanding myofibroblasts and their responses to mechanical loading allows the development of new scar therapeutics. A review of the current clinical and preclinical studies suggests that existing treatment strategies only reduce scarring on a small scale after wound closure and result in poor functional and aesthetic outcomes. Therefore, the perspective of mechanotherapies needs to consider the application of both mechanical forces and biochemical cues to achieve optimal scarring. Moreover, early intervention is critical in wound management; thus, mechanoregulation should be conducted during the healing process to avoid scar maturation. Future studies should either consider combining mechanical loading (pressure) therapies with tension offloading approaches for scar management or developing more effective early therapies based on contraction-blocking biomaterials for the prevention of pathological scarring.

Biological Properties of Yeast-based Mannoprotein for Prospective Biomedical Applications.

BACKGROUND: Natural products constitute more than half of all biomolecules lately being used in clinical settings. Mannoprotein derived from the yeast cell wall has found full biotechnological applications. OBJECTIVE: This study was intended to investigate the antioxidant, anticancer, and toxicological properties of Kluyveromyces marxianus mannoprotein (KM). METHODS: The KM extract was obtained through a sequence of operations, including centrifugation for cell isolation, precipitation with potassium citrate/sodium metabisulfite, and recovery and purification. Its antioxidant, growth inhibition, macrophage mitogenic, and toxic activities were evaluated for its future use in the biomedical field. RESULTS: Significant inhibitory effects of KM were obtained on reactive species. It showed antiproliferative activity against HeLa (human cervical adenocarcinoma) and MCF-7 (human breast cancer) cell lines with no toxic effects on HUVECs (human umbilical vein endothelial cells). The in vitro model of CHO-K1 (Chinese hamster ovary) cell lines did not show the cytotoxic and genotoxic of KM. Moreover, it enhanced macrophage activity in terms of nitric oxide (NO) production and viability. No sign of acute toxicity was found in BALB/c mice, and body weight remained unchanged in guinea pigs over three months. CONCLUSION: Comprehensive biological evaluations in this study are expected to expand the potential of KM as a natural material.

Cerium Oxide Nanoparticles: Recent Advances in Tissue Engineering.

Submicron biomaterials have recently been found with a wide range of applications for biomedical purposes, mostly due to a considerable decrement in size and an increment in surface area. There have been several attempts to use innovative nanoscale biomaterials for tissue repair and tissue regeneration. One of the most significant metal oxide nanoparticles (NPs), with numerous potential uses in future medicine, is engineered cerium oxide (CeO2) nanoparticles (CeONPs), also known as nanoceria. Although many advancements have been reported so far, nanotoxicological studies suggest that the nanomaterial's characteristics lie behind its potential toxicity. Particularly, physicochemical properties can explain the positive and negative interactions between CeONPs and biosystems at molecular levels. This review represents recent advances of CeONPs in biomedical engineering, with a special focus on tissue engineering and regenerative medicine. In addition, a summary report of the toxicity evidence on CeONPs with a view toward their biomedical applications and physicochemical properties is presented. Considering the critical role of nanoengineering in the manipulation and optimization of CeONPs, it is expected that this class of nanoengineered biomaterials plays a promising role in the future of tissue engineering and regenerative medicine.

Sol-Gel Synthesis, Physico-Chemical and Biological Characterization of Cerium Oxide/Polyallylamine Nanoparticles.

Cerium oxide nanoparticles (CeO2-NPs) have great applications in different industries, including nanomedicine. However, some studies report CeO2-NPs-related toxicity issues that limit their usage and efficiency. In this study, the sol-gel method was applied to the synthesis of CeO2-NPs using poly(allylamine) (PAA) as a capping and/or stabilizing agent. The different molecular weights of PAA (15,000, 17,000, and 65,000 g/mol) were used to investigate the physico-chemical and biological properties of the NPs. In order to understand their performance as an anticancer agent, three cell lines (MCF7, HeLa, and erythrocyte) were analyzed by MTT assay and RBC hemolysis assay. The results showed that the CeO2-NPs had anticancer effects on the viability of MCF7 cells with half-maximal inhibitory concentration (IC50) values of 17.44 ± 7.32, 6.17 ± 1.68, and 0.12 ± 0.03 µg/mL for PAA15000, PAA17000, PAA65000, respectively. As for HeLa cells, IC50 values reduced considerably to 8.09 ± 1.55, 2.11 ± 0.33, and 0.20 ± 0.01 µg/mL, in order. A decrease in the viability of cancer cells was associated with the 50% hemolytic concentration (HC50) of 0.022 ± 0.001 mg/mL for PAA15000, 3.74 ± 0.58 mg/mL for PAA17000, and 7.35 ± 1.32 mg/mL for PAA65000. Ultraviolet-Visible (UV-vis) spectroscopy indicated that an increase in the PAA molecular weight led to a blue shift in the bandgap and high amounts of Ce3+ on the surface of the nanoceria. Thus, PAA65000 could be considered as a biocompatible nanoengineered biomaterial for potential applications in cancer nanomedicine.

Correlation Between Biofilm Formation and Antibiotic Resistance in MRSA and MSSA Isolated from Clinical Samples in Iran: A Systematic Review and Meta-Analysis.

Objectives: This study aimed at reviewing the correlation between biofilm formation and antibiotic resistance in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates. Materials and Methods: This review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocols. The literature search was conducted in PubMed, Web of Science (ISI), and Scopus databases. Combinations of Mesh terms such as "biofilms" OR "biofilm formation," AND "Drug Resistance" OR "Antimicrobial Drug Resistance" OR "Antibiotic Resistance" AND "Staphylococcus aureus" OR "Methicillin-resistant Staphylococcus aureus" or "MRSA" AND "Methicillin-sensitive Staphylococcus aureus" OR "MSSA" AND "biofilm-related genes" AND "Prevalence" AND "Iran" were searched. Two reviewers independently searched the databases. Analyses were performed in Comprehensive Meta-Analysis software. The random-effects model was used to obtain the combined prevalence with a 95% confidence interval (CI). Results: The combined prevalence of MRSA retrieved from Iranian clinical samples was 48.3% (95% CI: 40.8-55.9). The pooled rate of biofilm formation in MRSA strains was reported as 80.9% (95% CI: 67.8-89.4). Overall, 52.9%, 45.3%, and 22.5% of MRSA isolates were strong, moderate, and weak biofilm producers, respectively. The highest frequency of biofilm-related genes was observed for icaD gene (67.7%) followed by clfA gene with a frequency of 64.7%. Among seven studies that addressed the relationship between biofilm formation and antibiotic resistance, six reported positive associations. Conclusions: Regarding the MRSA strains, they had a significantly higher ability of biofilm formation than MSSA strains; therefore, preventive measures against infections caused by them are required.

Antiproliferative Effects of Free and Encapsulated Hypericum Perforatum L. Extract and Its Potential Interaction with Doxorubicin for Esophageal Squamous Cell Carcinoma.

OBJECTIVES: Esophageal squamous cell carcinoma (ESCC) is considered as a deadly medical condition that affects a growing number of people worldwide. Targeted therapy of ESCC has been suggested recently and required extensive research. With cyclin D1 as a therapeutic target, the present study aimed at evaluating the anticancer effects of doxorubicin (Dox) or Hypericum perforatum L. (HP) extract encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles on the ESCC cell line KYSE30. METHODS: Nanoparticles were prepared using double emulsion method. Cytotoxicity assay was carried out to measure the anti-proliferation activity of Dox-loaded (Dox NPs) and HP-loaded nanoparticles (HP NPs) against both cancer and normal cell lines. The mRNA gene expression of cyclin D1 was evaluated to validate the cytotoxicity studies at molecular level. RESULTS: Free drugs and nanoparticles significantly inhibited KYSE30 cells by 55-73% and slightly affected normal cells up to 29%. The IC50 of Dox NPs and HP NPs was ~ 0.04-0.06 mg/mL and ~ 0.6-0.7 mg/mL, respectively. Significant decrease occurred in cyclin D1 expression by Dox NPs and HP NPs (P < 0.05). Exposure of KYSE-30 cells to combined treatments including both Dox and HP extract significantly increased the level of cyclin D1 expression as compared to those with individual treatments (P < 0.05). CONCLUSION: Dox NPs and HP NPs can successfully and specifically target ESCC cells through downregulation of cyclin D1. The simultaneous use of Dox and HP extract should be avoided for the treatment of ESCC.

An In Vitro and In Vivo Cholinesterase Inhibitory Activity of Pistacia khinjuk and Allium sativum Essential Oils.

OBJECTIVES: Alzheimer's disease (AD), an overwhelming neurodegenerative disease, has deleterious effects on the brain that consequently causes memory loss and language impairment. This study was intended to investigate the neuroprotective activity of the two essential oils (EOs) from Iranian Pistacia khinjuk (PK) leaves and Allium sativum (AS) cloves against ß-Amyloid 25-35 (Aß25-35) induced elevation of cholinesterase enzymes in AD. METHODS: The EOs of PK (PKEO) and AS (ASEO) were prepared and analyzed in terms of extraction yield, phenolic content, and cholinergic markers in vitro. Moreover, both were administered orally to adult male Wistar rats at concentrations of 1, 2, and 3%. The inhibitory potential of PKEO and ASEO was compared with Donepezil (0.75 mg/kg) against the high activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. RESULTS: PKEO reached an inhibition rate of 83.6% and 81.4% against AChE and BChE, respectively. ASEO had lower anti-cholinesterase activity (65.4% and 31.5% for the inhibition AChE and BChE). PKEO was found to have more phenolic content than ASEO. A significantly positive correlation was observed between the total phenolics and anti-cholinesterase potential. In rats, both EOs decreased the enzyme activity in a concentration-dependent manner. As compared with Donepezil, the significant difference in the AChE and BChE inhibition occurred as rats were treated with PKEO 3% (p < 0.05). CONCLUSION: It could be concluded that PKEO and ASEO are potent inhibitors of AChE and BChE in rats that hold promise to be used for the treatment of AD.

Antiproliferative Activity of Hypericum perforatum, Achillea millefolium, and Aloe vera in Interaction with the Prostatic Activity of CD82.

BACKGROUND: In recent years, prostate cancer prevails as one of the lead cancers affecting men. Currently, prostate cancer research involves the phytochemical study of plants with anti-tumour effects. This study compares the anti-tumour effects of three plant species indigenous to Iran and their interaction with cluster of differentiation (CD)-82 protein, a therapeutic target found in prostate cancer cells. METHODS: The extracts of Hypericum perforatum, Achillea millefolium, and Aloe vera were prepared and their toxicological, cellular and gene expression responses were evaluated in PC-3 human prostate cancer cells and normal human chondrocyte cell line C28/I2. They were exposed to different concentrations of the plants (10 mg/mL, 5 mg/mL, 1 mg/mL, 100 µg/mL, 10 µg/mL, and 1 µg/mL) at three exposure time points (24, 48, 72 hours) to determine cancer cell cytotoxicity and gene expression profiles. RESULTS: : Half-maximal inhibitory concentration (IC50) in PC-3 cells ranged from 0.6 to 8.5 mg/mL for H. perforatum extract, from 0.4 to 7.5 mg/mL for A. Millefolium extract, and from 0.2 to 8.0 mg/mL for A. vera extract in a time-dependent manner. A. vera extract caused the highest cell death levels in PC-3 cells (94%) and C28/I2 cells (57%) after 48 hours. A 1.97-, 3.00-, and 3.48-fold increase in relative gene expression of CD82 was observed for H. perforatum, A. millefolium, and A. vera extracts, respectively. CONCLUSION: A. vera and A. millefolium extracts are a selective inhibitor of prostate cancer cells and a potent activator of CD82 expression.

The synergistic effects of shear stress and cyclic hydrostatic pressure modulate chondrogenic induction of human mesenchymal stem cells.

PURPOSE: In this study, we examined chondrogenic regulation of 2 types of mesenchymal stem cells seeded on the bioengineered substrate in monolayer cultures under mechanically defined conditions to mimic the in vivo microenvironment of chondrocytes within articular cartilage tissues. METHODS: Human adipose-derived mesenchymal stem cells (ASCs) and bone marrow mesenchymal stem cells (BSCs) were exposed to 0.2 Pa shear stress, 3 MPa cyclic hydrostatic pressure, and combined loading with different sequences on chemically designed medical-grade silicone rubber, while no soluble growth factors were added to the culture medium. The expression levels of chondrogenic-specific genes of SOX9, aggrecan, and type II collagen (Col II) were measured. Results were compared to those of cells treated by biological growth factor. RESULTS: Gene expression patterns were dependent on the loading regime. Moreover, the source of mesenchymal stem cells (adipose or bone marrow) was influential in gene expression. Overall, enhanced expression of chondrogenic markers was found through application of mechanical stimuli. The response was generally found to be significantly promoted when the 2 loading regimes were superimposed. CONCLUSIONS: Differentiation of ASCs was shown by a modest increase in gene expression profiles. In general, BSCs expressed higher levels of chondrogenic gene expression than ASCs after 3 weeks. A greater effect on Col II and SOX9 mRNA expression was observed when combined loadings were applied. Results may be applied in determining the proper loading sequence for obtaining functional target cells in cartilage engineering applications.

Effects of surface viscoelasticity on cellular responses of endothelial cells.

BACKGROUND: One area of nanoscience deals with nanoscopic interactions between nanostructured materials and biological systems. To elucidate the effects of the substrate surface morphology and viscoelasticity on cell proliferation, fractal analysis was performed on endothelial cells cultured on nanocomposite samples based on silicone rubber (SR) and various concentrations of organomodified nanoclay (OC). METHODS: The nanoclay/SR ratio was tailored to enhance cell behavior via changes in sample substrate surface roughness and viscoelasticity. RESULTS: Surface roughness of the cured SR filled with negatively-charged nanosilicate layers had a greater effect than elasticity on cell growth. The surface roughness of SR nanocomposite samples increased with increasing the OC content, leading to enhanced cell growth and extracellular matrix (ECM) remodeling. This was consistent with the decrease in SR segmental motions and damping factor as the primary viscoelastic parameters by the nanosilicate layers with increasing clay concentrations. CONCLUSIONS: The inclusion of clay nanolayers affected the growth and behavior of endothelial cells on microtextured SR.

Anticancer Activity of Nanoparticles Based on PLGA and its Co-polymer: In-vitro Evaluation.

Attempts have been made to prepare nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) and doxorubicin. Biological evaluation and physio-chemical characterizations were performed to elucidate the effects of initial drug loading and polymer composition on nanoparticle properties and its antitumor activity. PLGA nanoparticles were formulated by sonication method. Lactide/glycolide ratio and doxorubicin amounts have been tailored. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were employed to identify the presence of doxorubicin within nanospheres. The in vitro release studies were performed to determine the initial ant net release rates over 24 h and 20 days, respectively. Furthermore, cytotoxicity assay was measured to evaluate therapeutic potency of doxorubicin-loaded nanoparticles. Spectroscopy and thermal results showed that doxorubicin was loaded into the particles successfully. It was observed that lactide/glycolide content of PLGA nanoparticles containing doxorubicin has more prominent role in tuning particle characteristics. Doxorubicin release profiles from PLGA 75 nanospheres demonstrated that the cumulative release rate increased slightly and higher initial burst was detected in comparison to PLGA 50 nanoparticles. MTT data revealed doxorubicin induced antitumor activity was enhanced by encapsulation process, and increasing drug loading and glycolide portion. The results led to the conclusion that by controlling the drug loading and the polymer hydrophilicity, we can adjust the drug targeting and blood clearance, which may play a more prominent role for application in chemotherapy.