HA-hybrid matrix composite coating on Ti-Cp for biomedical application.

Calcium phosphate coatings have been applied to titanium metal substrates and their alloys as a synergistic alternative capable of combining the mechanical properties of metals and the excellent bioactive properties provided by ceramic materials. However, the unsatisfactory adhesion of hydroxyapatite coatings on metallic substrates, as well as their limitation when subjected to mechanical stresses have been reported as a limitation. Biofunctional coatings have been proposed as an alternative to single ceramic coatings, aiming at optimizing the long-term clinical success of biomaterials such as Ti. This work aims at evaluating the morphological properties and biological behavior of Ti-cp coated with matrix composite coating hydroxyapatite-containing hybrid. The hybrid matrix was obtained from TEOS and MTES silicon precursors, with dispersed hydroxyapatite suspended by dip coating. For the morphological characterization FTIR, SEM/FEG, AFM and contact angle measurement were used. Biological behavior was evaluated for toxicity, cell viability and the osteogenic differentiation capacity of mesenchymal stem cells. The composite coatings obtained showed regular dispersion of hydroxyapatite particles in the hybrid matrix, with uniform coating adhering to the Ti-Cp substrate. Nevertheless, although they provided similar viability behavior of mesenchymal stem cells to the Ti-Cp substrate, the evaluated coatings did not present osteoinductive properties. This result is probably due to the pronounced hydrophobic behavior caused by the incorporation of HA.

Noninferiority of Simplified Dolutegravir Monotherapy Compared to Continued Combination Antiretroviral Therapy That Was Initiated During Primary Human Immunodeficiency Virus Infection: A Randomized, Controlled, Multisite, Open-label, Noninferiority Trial.

BACKGROUND: Patients who start combination antiretroviral therapy (cART) during primary human immunodeficiency virus type 1 (HIV-1) infection show a smaller HIV-1 latent reservoir, less immune activation, and less viral diversity compared to patients who start cART during chronic infection. We conducted a pilot study to determine whether these properties would allow sustained virological suppression after simplification of cART to dolutegravir monotherapy. METHODS: EARLY-SIMPLIFIED is a randomized, open-label, noninferiority trial. Patients who started cART <180 days after a documented primary HIV-1 infection and had an HIV-1 RNA <50 copies/mL plasma for at least 48 weeks were randomized (2:1) to monotherapy with dolutegravir 50 mg once daily or to continuation of cART. The primary efficacy endpoint was the proportion of patients with <50 HIV-1 RNA copies/mL on or before week 48; noninferiority margin 10%. RESULTS: Of the 101 patients randomized, 68 were assigned to simplification to dolutegravir monotherapy and 33 to continuation of cART. At week 48 in the per-protocol population, 67/67 (100%) had virological response in the dolutegravir monotherapy group vs 32/32 (100%) in the cART group (difference, 0.00%; 95% confidence interval, -100%, 4.76%). This showed noninferiority of the dolutegravir monotherapy at the prespecified level. CONCLUSION: In this pilot study consisting of patients who initiated cART during primary HIV-1 infection and had <50 HIV-1 RNA copies/mL for at least 48 weeks, monotherapy with once-daily dolutegravir was noninferior to cART. Our results suggest that future simplification studies should use a stratification according to time of HIV infection and start of first cART. CLINICAL TRIALS REGISTRATION: NCT02551523.

High Rates of Subsequent Asymptomatic Sexually Transmitted Infections and Risky Sexual Behavior in Patients Initially Presenting With Primary Human Immunodeficiency Virus-1 Infection.

Background: Knowledge of the risk factors of individuals with an asymptomatic sexually transmitted infection (STI) is essential for implementation of targeted STI screening strategies. Methods: Between June 2015 and January 2017, an STI screening was offered to all participants in the Zurich Primary human immunodeficiency virus (HIV)-1 Infection study. Patients were tested for gonorrhea, chlamydia, syphilis, and hepatitis C virus (HCV). Results: Of 214 participants, 174 (81%) were screened at least once. Most patients were men who have sex with men (MSM) (87.4%). Presenting with a primary HIV infection was associated with higher odds for later risky sexual behavior, as compared with presenting in the chronic phase (odds ratio [OR], 5.58; 95% confidence interval [CI], 3.68-8.8). In total, 79 STIs were detected, reflecting a high period prevalence of 33.3% (58 of 174 patients). Sixty-six percent of patients (52 of 79) were asymptomatic. Most common STIs were chlamydia (50.6%; 40 of 79 patients), gonorrhea (25.3%; 20 of 79), and syphilis (19%; 15 of 79). In a multivariable model, engaging in insertive (OR, 6.48; 95% CI, 1.14-36.76) or both insertive and receptive (4.61; 1.01-20.96) anal intercourse, STI symptoms (3.4; 1.68-6.89), and condomless sex (2.06; 1.14-3.74) were positively correlated with a positive screening result. The hazard of an incident STI increased with the presence of STI symptoms (hazard ratio, 3.03; 95% CI, 1.17-7.84) and any recent drug use (2.63; 1-6.9). Conclusions: A trimonthly STI screening including asymptomatic individuals should be considered in this population, particularly in MSM who report sexual risk behavior. Clinical Trial Registration: NCT 00537966.

Carious deciduous teeth are a potential source for dental pulp stem cells.

OBJECTIVE: The objectives of this study are to isolate, cultivate, and characterize stem cells from the pulp of carious deciduous teeth (SCCD) and compare them to those retrieved from sound deciduous teeth (SHED--stem cells from human exfoliated deciduous teeth). MATERIAL AND METHODS: Cells were obtained of dental pulp collected from sound (n = 10) and carious (n = 10) deciduous human teeth. Rate of isolation, proliferation assay (0, 1, 3, 5, and 7 days), STRO-1, mesenchymal (CD29, CD73, and CD90) and hematopoietic surface marker expression (CD14, CD34, CD45, HLA-DR), and differentiation capacity were evaluated. RESULTS: Isolation success rates were 70 and 80 % from the carious and sound groups, respectively. SCCD and SHED presented similar proliferation rate. There were no statistical differences between the groups for the tested surface markers. The cells from sound and carious deciduous teeth were positive for CD29, CD73, and CD90 and negative for CD14, CD34, CD45, and HLA-DR and were capable of differentiating into osteogenic, chondrogenic, and adipogenic lineages. CONCLUSION: SCCD demonstrated a similar pattern of proliferation, immunophenotypical characteristics, and differentiation ability as those obtained from sound deciduous teeth. These SCCD represent a feasible source of stem cells. CLINICAL RELEVANCE: Decayed deciduous teeth have been usually discarded once the pulp tissue could be damaged and the activity of stem cells compromised. These findings show that stem cells from carious deciduous teeth can be applicable source for cell-based therapies in tissue regeneration.

Biological applications of nanobiotechnology.

Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices derived from engineering, physics, chemistry, and biology. Nanotechnology has opened up by rapid advances in science and technology, creating new opportunities for advances in the fields of medicine, electronics, foods, and the environment. Nanoscale structures and materials (nanoparticles, nanowires, nanofibers, nanotubes) have been explored in many biological applications (biosensing, biological separation, molecular imaging, anticancer therapy) because their novel properties and functions differ drastically from their bulk counterparts. Their high volume/surface ratio, improved solubility, and multifunctionality open many new possibilities. The objective of this review is to describe the potential benefits and impacts of the nanobiotechnology in different areas.

Update on the main use of biomaterials and techniques associated with tissue engineering.

Regenerative medicine involves the study of cells, signaling cues and biomatrices to restore normal function of tissues and organs. To develop the matrices for use in tissue engineering there are three main groups of biomaterials: (i) naturally derived materials; (ii) synthetic polymers; and (iii) decellularized organ or tissue scaffolds. These biomaterials, in various forms such as hydrogels, nanofibers and 3D scaffolds, among others, have been employed for different tissue regeneration purposes, with several techniques involved in their production, including rapid prototyping, tissue decellularization and electrospinning. In this review, the main topics of hydrogels, 3D printing and electrospun scaffolds, other biomaterials and decellularization and recellularization will be discussed.

Treatment of a burn animal model with functionalized tridimensional electrospun biomaterials.

Laminin-functionalized poly-d,l-lactic acid scaffolds were produced. Following this, mesenchymal stem cells and keratinocytes were seeded on biomaterials for the in vivo experiments, where the biomaterials with or without cells were implanted. The analysis is comprised of the visual aspect and mean size of the lesion plus the histology and gene expression. The results showed that the cells occupied all the structure of the scaffolds in all the groups. After nine days of in vivo experiments, the defect size did not show statistical difference among the groups, although the groups with the poly-d,l-lactic acid/Lam biomaterial had the lowest lesion size and presented the best visual aspect of the wound. Gene expression analysis showed considerable increase of tumor growth factor beta 1 expression, increased vascular endothelial growth factor and balance of the BAX/Bcl-2 ratio when compared to the lesion group. Histological analysis showed well-formed tissue in the groups where the biomaterials and biomaterials plus cells were used. In some animals, in which biomaterials and cells were used, the epidermis was formed throughout the length of the wound. In conclusion, these biomaterials were found to be capable of providing support for the growth of cells and stimulated the healing of the skin, which was improved by the use of cells.

3D-printed PCL scaffolds for the cultivation of mesenchymal stem cells.

INTRODUCTION: Tissue engineering is a field which is currently under a great deal of investigation for the development and/or restoration of tissue and organs, through the combination of cell therapy with biomaterials. Rapid prototyping or additive manufacturing is a versatile technology which makes possible the fabrication of three dimensional (3D) structures from a wide range of materials with complex geometry and accuracy, such as scaffolds. AIM: The aim of this study has been to investigate the interaction between mesenchymal stem cells with poly (ε-caprolactone) (PCL) biomaterials used for obtaining scaffolds through additive manufacturing. MATERIALS AND METHODS: Scanning electron microscopy, confocal microscopy and biological assays were performed to analyse the successful interaction between the cells and the biomaterials. RESULTS: As a result, the number of viable cells attached to the scaffolds was lower when compared to the control group; however, it was possible to observe cells in the scaffolds since day 1 of analysis, with regions of confluence after 21 days of seeding. CONCLUSIONS: To conclude, these biomaterials are interesting if used as medical artifacts, principally in tissue with prolonged regeneration time and which requires 3D supports with good mechanical properties.

Neural Differentiation of Mesenchymal Stem Cells on Scaffolds for Nerve Tissue Engineering Applications.

Scaffolds produced by electrospinning act as supports for cell proliferation and differentiation, improved through the release of neurotrophic factors. The objective of this study was to develop aligned and random nanofiber scaffolds with and without nerve growth factor to evaluate the potential of mesenchymal stem cells (MSCs) for neural differentiation. Nanofiber morphology, diameter, degradability, cell morphology, adhesion, proliferation, viability, cytotoxicity, and neural differentiation were performed to characterize the scaffolds. The expression for nestin, ß-III tubulin, and neuron-specific enolase was also evaluated. The scaffolds demonstrated a satisfactory environment for MSC growth, being nontoxic. The MSCs cultivated on the scaffolds were able to adhere and proliferate. The evaluation of neural differentiation indicated that in all groups of scaffolds the MSCs were able to upregulate neural gene expression.

Development of a biomaterial associated with mesenchymal stem cells and keratinocytes for use as a skin substitute.

AIM: The present study has aimed to produce a cutaneous substitute, bringing together stem cells (mesenchymal stem cells) and keratinocytes, and an electrospun biomaterial. MATERIALS & METHODS: Three groups of scaffolds were studied: group 1, poly-dl-lactic acid (PDLLA); group 2, hydrolyzed PDLLA (PDLLA/NaOH) and group 3, PDLLA/Lam - a PDLLA/NaOH scaffold linked to laminin protein. They were characterized by physicochemical and biological parameters. RESULTS: As a result, the scaffolds presented well-formed and randomly distributed fibers. Group 3 showed the greatest hydrophilic characteristics. Group 1 showed a greater degradation rate after 14 days. Groups 2 and 3 presented molecular weight of about 40-50 Da. In general, group 3 showed the best results concerning cell adhesion and viability. CONCLUSION: This study associated two revolutionary fields, stem cells and nanotechnology, for use in regenerative medicine.

Electrospinning for regenerative medicine: a review of the main topics.

Electrospun fibers are promising tissue engineering scaffolds that offer the cells an environment that mimics the native extracellular matrix. Fibers with different characteristics can be produced by the electrospinning technique according to the needs of the tissue to be repaired. In this review, the process of electrospinning was examined, providing a description of the common techniques used for the physicochemical and biological characterization of electrospun fibers. The review also discusses the potential applications of electrospun scaffolds for tissue engineering, based on scientific literature.

Effects of cryopreservation on the characteristics of dental pulp stem cells of intact deciduous teeth.

OBJECTIVES: The aim of this study was to isolate and cultivate cells from the pulp of 7-day-cryopreserved intact deciduous human teeth and evaluate the effect of cryopreservation on dental pulp stem cell (DPSC) characteristics. DESIGN: Twenty-six deciduous teeth were collected and allocated in two groups: immediate cell isolation (non-cryopreserved group) and intact cryopreserved (cryopreserved group). The teeth were cryopreserved in dimethylsulfoxide solution and recovered after 7 days. The success rate of isolation, proliferation, surface markers (CD14, CD29, CD34, CD45, CD73, CD90, and HLA-DR), differentiation capacity, and morphology were evaluated. RESULTS: Isolation success rate was 61% and 30% for the non-cryopreserved and cryopreserved groups, respectively. There were no statistical differences between the groups for the tested surface markers. The cells in both groups were capable of differentiating into three mesenchymal lineages. No statistical differences between the groups were observed through the time course proliferation assay (0, 1, 3, 5, and 7 days); however, the mean time between isolation and the fifth passage was shorter for the non-cryopreserved group (p=0.035). The morphology of the cells was considered altered in the cryopreserved group. CONCLUSION: DPSCs were obtained from cryopreserved intact deciduous teeth without changes in the immunophenotypical characteristics and differentiation ability; however, lower culture rates, proliferation potential, and morphological alterations were observed in relation to the control group.

The effect of sterilization methods on electronspun poly(lactide-co-glycolide) and subsequent adhesion efficiency of mesenchymal stem cells.

The sterilization of scaffolds is an essential step for tissue engineering in vitro and, mainly, clinical biomaterial use. However, this process can cause changes in the structure and surface of the scaffolds. Therefore, the objective of this study was to investigate the effect of sterilization by ethanol, ultraviolet radiation (UVR) or antimicrobial solution (AMS) on poly(lactide-co-glycolide) (PLGA) scaffolds produced by the electrospinning technique. The properties of nanofibers and the cellular adhesion of mesenchymal stem cells to the scaffolds were analyzed after the treatments. All methods generated sterile scaffolds but showed some kind of damage to the scaffolds. Ethanol and AMS caused changes in the morphology and scaffold dimensions, which were not observed when using the UVR method. However, UVR caused a greater reduction in polymeric molecular weight, which increased proportionally with exposure time of treatment. Nanofibers sterilized with AMS for 1 h and 2 h showed greater cellular adhesion than the other methods, demonstrating their potential as a method for sterilizing PLGA nanofibers.

Mesenchymal stem cells and nanofibers as scaffolds for the regeneration of thyroid cartilage.

OBJECTIVES/HYPOTHESIS: The aim of this study has been to establish an alternative approach in the form of regeneration of the thyroid cartilage. STUDY DESIGN: Four 1-month old pigs (Sus scrofa) were used (divided into 3 groups) and submitted to general anesthetic to perform cervictomy with exposure of the thyroid cartilage in a total of 12 (twelve) samples. METHOD: A resection of 4.0 cm(2) of cartilage was carried out in the right upper region and in the left upper and lower left region of the cartilage, where a scaffold with or without stem cells was implanted. In the left lower region, no biomaterial was implanted and the defect was left open (lesion control [L]). RESULTS: The average extension of the cartilaginous neoformation of L group was 136.3 µm (± 9.6) and 387.7 µm (± 43.2) in the scaffold (SCA) group, presenting a significant statistical difference (P < 0.01). The analysis carried out on the lesion site sections of the cartilage of the larynx of the animals from the SCA group + mesenchymal stem cells (SCA+MSC) showed an average of the extension of neocartilage of 825.4 µm (± 122.1), showing a more extensive area of neocartilage when compared to the other groups. These results demonstrated a high significantly statistical difference (P < 0.001) when compared with the L and SCA groups. CONCLUSION: In 100% of the cases for which SCA+MSCs were used, a significant success in the cartilage growth and closing of the lesion in the thyroid cartilage was obtained compared to the other two groups for which MSCs were not used. LEVEL OF EVIDENCE: N/A.

Development of a new nanofiber scaffold for use with stem cells in a third degree burn animal model.

The combination of mesenchymal stem cells (MSCs) and nanotechnology to promote tissue engineering presents a strategy for the creation of new substitutes for tissues. Aiming at the utilization of the scaffolds of poly-d,l-lactic acid (PDLLA) associated or not with Spirulina biomass (PDLLA/Sp) in skin wounds, MSCs were seeded onto nanofibers produced by electrospinning. These matrices were evaluated for morphology and fiber diameter by scanning electron microscopy and their interaction with the MSCs by confocal microscopy analysis. The biomaterials were implanted in mice with burn imitating skin defects for up to 7 days and five groups were studied for healing characteristics. The scaffolds demonstrated fibrous and porous structures and, when implanted in the animals, they tolerated mechanical stress for up to two weeks. Seven days after the induction of lesions, a similar presence of ulceration, inflammation and fibrosis among all the treatments was observed. No group showed signs of re-epithelization, keratinization or presence of hair follicles on the lesion site. In conclusion, although there was no microscopical difference among all the groups, it is possible that more prolonged analysis would show different results. Moreover, the macroscopic analysis of the groups with the scaffolds showed better cicatrization in comparison with the control group.