A new technology for the treatment of premature ovarian insufficiency: Cell sheet.

Premature ovarian insufficiency (POI) is defined as the development of hypergonadotropic hypogonadism before the age of 40 with definitive treatment being absent. In the current study, we aim to compare the efficacy of the cell sheet method with an intravenous (IV) application of adipose-derived mesenchymal stem cells (AdMSCs) to the POI with an animal model. In the current prospective study, 6-to-8-week-old Sprague Dawley rats were generated four groups: (i) a control group in which only PBS was administered; (ii) an only-POI group generated by cyclophosphamide; (iii) a POI group treated by way of IV AdMSCs; and (iv) a POI group treated by way of the cell sheet method. Twenty-eight days after an oophorectomy was performed, intracardiac blood was taken. Follicle count, immunohistochemical examination for GDF9, BMP15, and TUNEL were conducted, gene expressions of GDF9 and BMP15 were examined, and E2 was measured in the serum samples. With hematoxylin-eosin, in the third group, multi oocytes follicles were the most remarkable finding. In the fourth group, most of the follicles presented normal morphology. GDF9 involvement was similar between the first and fourth groups. BMP-15 immunoreactivity, in contrast to fourth group, was weak in all stages in the second and third groups. The current attempt represents a pioneer study in the literature in which a cell sheet method is used for the first time in a POI model. These results suggest that the cell sheet method may be a feasible and efficient method for the stem cell treatment of models with POI and could be a new treatment approach in POI.

Biological nerve conduit model with de-epithelialized human amniotic membrane and adipose-derived mesenchymal stem cell sheet for repair of peripheral nerve defects.

In this study, a biological conduit, consisting of an adipocyte-derived mesenchymal stem cell (AdMSCs) sheet and amniotic membrane (AM), was designed for the reconstruction of peripheral nerve defects. To evaluate the effect of the produced conduit on neural regeneration, a 10-mm sciatic nerve defect was created in rats, and experiments were carried out on six groups, i.e., sham control group (SC), negative control group (NC), nerve autograft group (NG), the biological conduit (AdMSCs + AM) group, the commercial PGA tube conduit (PGA) group, and the conduit only consisting of AM (AM) group. The effects of different nerve repair methods on the peripheral nerve and gastrocnemius muscle were evaluated by functional, histological, and immunohistochemical tests. When the number of myelinated axons was compared between the groups of AdMSCs + AM and PGA, it was higher in the AdMSCs + AM group (p < 0.05). The percentage of gastrocnemius collagen bundle area of AdMSCs + AM group was found to be statistically lower than the PGA group (p < 0.05). The muscle fiber diameter of AdMSCs + AM group was lower than that of the NG group, but significantly higher than that of the PGA group and the AM group (p < 0.001). Muscle weight index was significantly higher in the AdMSCs + AM group compared to the PGA group (p < 0.05). It was observed that nerve regeneration was faster in the AdMSCs + AM group, and there was an earlier improvement in pin-prick score and sciatic functional index compared to the PGA group and the AM group. In conclusion, the biological conduit prepared from the AdMSCs sheet and AM is regarded as a new biological conduit that can be used as an alternative treatment method to nerve autograft in clinical applications.

Effects of radiofrequency exposure on in vitro blood-brain barrier permeability in the presence of magnetic nanoparticles.

The blood-brain barrier (BBB) remains a major obstacle for the delivery of drugs in the treatment of many neurological diseases. In this study, we aimed to investigate the effects of radiofrequency electromagnetic fields (RF-EMFs) on the permeability of an in vitro BBB model under RF exposure alone, or in the presence of nanoparticles (NPs). For this purpose, an in vitro BBB model was established by seeding human umbilical vein endothelial cells (HUVECs) and human glioblastoma cell line (T98G) on the apical and basolateral sides of the transwell membrane, respectively. The integrity of the BBB model was confirmed by measuring transendothelial electrical resistance (TEER), and a fluorescein isothiocyanate (FITC)-dextran permeability assay was performed when the resistance reached 120 Ω cm2. After the RF-field exposure (13.56 MHz, 80 W, 10 min), we found that FITC-dextran transported across the in vitro BBB was increased 10-fold compared to FITC-dextran transported without an RF-field. This notable phenomenon, which can be called the burst permeability RF effect (BP-RF), has been proposed for the first time in the literature. Subsequently, the effect of the RF-field on BBB permeability was also investigated in the presence of superparamagnetic iron oxide nanoparticles (SPIONs) and magnetic poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-b-PEG) nanoparticles (m-PNPs). It was found that the amount of both transported NPs on the basolateral sides increased after exposure to the RF-field. As a result, the RF-field can be applied simultaneously during treatment with clinical agents or nanocarriers, improving the permeability of the BBB, which may contribute to therapeutic efficacy of many drugs that are used in neurological diseases.

Photobiomodulation with polychromatic light (600-1200 nm) improves fat graft survival by increasing adipocyte viability, neovascularization, and reducing inflammation in a rat model.

OBJECTIVES: Unpredictability with the final volume and viability of the graft are the major concerns in fat grafting. An experimental study was conducted to increase graft retention using photobiomodulation (PBM) with polychromatic light in near-infrared region (600-1200 nm) by utilizing its stimulatory effects on angiogenesis, neovascularization, adipocyte viability, and anti-inflammatory properties. METHODS: A total of 24 rats were divided into four groups (n = 6) according to the applied polychromatic light protocol to the recipient site (none, before fat transfer, after fat transfer, and combined). In all groups, inguinal fat pad was excised, measured for volume and weight, and transferred to the dorsum of the rat. At the end of the experiment, fat grafts were harvested from the recipient site for volume and weight measurements, histological, and immunohistochemical evaluation. RESULTS: Intergroup comparison revealed that fat graft retention regarding weight and volume, was significantly superior in Group IV (p = 0.049 and p = 0.043, respectively), which polychromatic light was applied both before and after transfer of the graft. Hematoxylin-eosin and Masson's trichrome stained sections showed absence of necrosis, fibrosis, inflammation, cyst formation, and increased vascularization of both inner and outer zones of the grafts in Group IV. Also, immunohistochemical staining scores for perilipin (indicator for adipocyte viability), CD31 and VEGF (indicators for angiogenesis and neovascularization) were significantly higher (p < 0.001). Ki67 scores were significantly lower in this group because of anti-inflammatory environment (p < 0.001). CONCLUSIONS: Application of PBM to the recipient site before and after fat transfer improved outcomes in rats at 56 day after fat grafting by means of volume retention, increased neovascularization and adipocyte viability and reduced necrosis, fibrosis and inflammation.

Photobiomodulation combined with adipose-derived stem cells encapsulated in methacrylated gelatin hydrogels enhances in vivo bone regeneration.

Reconstruction of bone defects is still a significant challenge. The aim of this study was to evaluate the effect of application of photobiomodulation (PBM) to enhance in vivo bone regeneration and osteogenic differentiation potential of adipose-derived stem cells (ADSCs) encapsulated in methacrylated gelatin (GEL-MA) hydrogels. Thirty-six Sprague-Dawley rats were randomly separated into 3 experimental groups (n = 12 each). The groups were control/blank defect (I), GEL-MA hydrogel (II), and ADSC-loaded GEL-MA (GEL-MA+ADSC) hydrogel (III). Biparietal critical sized bone defects (6 mm in size) are created in each animal. Half of the animals from each group (n = 6 each) were randomly selected for PBM application using polychromatic light in the near infrared region, 600-1200 nm. PBM was administered from 10 cm distance cranially in 48 h interval. The calvaria were harvested at the 20th week, and macroscopic, microtomographic, and histologic evaluation were performed for further analysis. Microtomographic evaluation demonstrated the highest result for mineralized matrix formation (MMF) in group III. PBM receiving samples of group III showed mean MMF of 79.93±3.41%, whereas the non-PBM receiving samples revealed mean MMF of 60.62±6.34 % (p=0.002). In terms of histologic evaluation of bone defect repair, the higher scores were obtained in the groups II and III when compared to the control group (2.0 for both PBM receiving and non-receiving specimens; p<0.001). ADSC-loaded microwave-induced GEL-MA hydrogels and periodic application of photobiomodulation with polychromatic light appear to have beneficial effect on bone regeneration and can stimulate ADSCs for osteogenic differentiation.

Effect of melatonin/BMP-2 co-delivery scaffolds on the osteoclast activity.

Bone morphogenetic protein two (BMP-2) has been widely used as an osteoinductive agent in the treatment of bone diseases. However, some side effects, such as osteoclast activation have emerged when it was used at high doses. In this study, by considering the osteoclast-suppressing capability of melatonin (MEL), its effect on osteoclast differentiation induced by BMP-2 was investigated. These two factors, MEL and BMP-2, were embedded into chitosan/hydroxyapatite (HAp) scaffolds that were characterized morphologically by scanning electron microscopy (SEM) and micro-computed tomography (µ-CT). Release profiles of MEL and BMP-2 from scaffolds were determined in vitro and then, the differentiation of RAW 264.7 cells to osteoclasts was investigated on the scaffolds. Results of tartrate-resistant acid phosphatase (TRAP) staining, SEM imaging and expression of cathepsin K gene showed that, in the presence of BMP-2, osteoclast differentiation increased, whereas it decreased in MEL and MEL/BMP-2 embedded scaffolds suggesting that melatonin successfully attenuated osteoclast differentiation induced by BMP-2. Thus, the MEL/BMP-2 loaded chitosan/HAp scaffolds that have dual function in enhancing bone formation and inhibiting osteoclast activity are recommended biomaterials in the field of bone regeneration.

A simple and efficient method for cultivation of limbal explant stem cells with clinically safe potential.

BACKGROUND: Several methods to cultivate limbal epithelial stem cells (LESCs) in vitro with the support of feeder layers and different growth medium formulations have been established for several years. The initial green medium consists of various ingredients that exhibit a non-optimal level of biosafety, therefore, different modifications have been made to suit it to safe clinical applications. However, the question of which formulation is the most appropriate remains to be answered. AIMS: This study evaluated the outgrowth kinetics and stemness of cells cultured from human limbal explants with the aim of preserving LESC characteristics in the human-derived platelet-rich fibrin (HPRF)-conditioned medium with no feeder cell layer or carrier for the first time. The final composition of the cell culture system included only human-derived products without any xenobiotic or chemical substances to minimize the potential risk for human health, which will be useful for clinical purposes. METHODS: To test our hypothesis, limbal explants were incubated with either Dulbecco's Modified Eagle's Medium (DMEM)/F12-10% human serum (HS), human-derived amniotic membrane (HAM)-conditioned DMEM/F12-10% HS or HPRF-conditioned DMEM/F12-10% HS to determine whether outgrowth kinetics and stemness of cells show any differences among groups. RESULTS: The results showed that the HPRF-conditioned medium showed higher concentration levels of growth factors, which may be involved in the promotion of LESC expansion while preserving the stem cell characteristics. HPRF-conditioned medium had significantly superior capacity to enhance the cell growth rate, the stem/progenitor cell phenotype and the expressions of putative stem cell markers. CONCLUSION: This novel xeno-feeder-chemical-free, completely human-derived and biologically safe culture system including HPRF and HS would be of interest to replace conventional cell culture strategies to meet safety requirements mandatory for clinical use in humans.

Photobiomodulation with polychromatic light increases zone 4 survival of transverse rectus abdominis musculocutaneous flap.

OBJECTIVE: The aim of this study was to evaluate the effect of relatively novel approach of application of polychromatic light waves on flap survival of experimental musculocutaneous flap model and to investigate efficacy of this modality as a delay procedure to increase vascularization of zone 4 of transverse rectus abdominis musculocutaneous (TRAM) flap. METHODS: Twenty-one Wistar rats were randomized and divided into 3 experimental groups (n = 7 each). In group 1 (control group), after being raised, the TRAM flap was sutured back to its bed without any further intervention. In group 2 (delay group), photobiomodulation (PBM) was applied for 7 days as a delay procedure, before elevation of the flap. In group 3 (PBM group), the TRAM flap was elevated, and PBM was administered immediately after the flap was sutured back to its bed for therapeutic purpose. PBM was applied in 48 hours interval from 10 cm. distance to the whole abdominal wall both in groups 2 and 3 for one week. After 7 days of postoperative follow-up, as the demarcation of necrosis of the skin paddle was obvious, skin flap survival was further evaluated by macroscopic, histological and microangiographic analysis. RESULTS: The mean percentage of skin flap necrosis was 56.17 ± 23.68 for group 1, 30.92 ± 17.46 for group 2 and 22.73 ± 12.98 for group 3 PBM receiving groups 2 and 3 revealed less necrosis when compared to control group and this difference was statistically significant. Vascularization in zone 4 of PBM applied groups 2 and 3 was higher compared to group 1 (P = 0.001). Acute inflammation in zone 4 of group 1 was significantly higher compared to groups 2 and 3 (P = 0.025). Similarly, evaluation of zone 1 of the flaps reveled more inflammation and less vascularization among the samples of the control group (P = 0.006 and P = 0.007, respectively). Comparison of PBM receiving two groups did not demonstrate further difference in means of vascularization and inflammation density (P = 0.259). CONCLUSION: Application of PBM in polychromatic fashion enhances skin flap survival in experimental TRAM flap model both on preoperative basis as a delay procedure or as a therapeutic approach. Lasers Surg. 51:538-549, 2019. © 2019 Wiley Periodicals, Inc.

Chitosan-based double-faced barrier membrane coated with functional nanostructures and loaded with BMP-6.

In the present study, a chitosan-based, multifunctional and double-faced barrier membrane was developed for the periodontitis therapy. The porous surface of the membrane was coated with bone-like hydroxyapatite (HA) produced by microwave-assisted biomimetic method and enriched with bone morphogenetic factor 6 (BMP-6) to enhance the bioactivity of chitosan. This surface of the membrane was designed to be in contact with the hard tissue that was damaged due to periodontitis. Otherwise the nonporous surface of membrane, which is in contact with the inflammatory soft tissue, was coated with electrospun polycaprolactone (PCL) fibers to prevent the migration of epithelial cells to the defect area. PrestoBlue, Scanning Electron Microscope (SEM) and real-time PCR results demonstrated that while porous surface of the membrane was enhancing the proliferation and differentiation of MC3T3-E1 preosteoblasts, nonporous surface of membrane did not allow migration of epithelial Madine Darby Bovine Kidney (MDBK) cells. The barrier membrane developed here is biodegradable and can be easily manipulated, has osteogenic activity and inactivity for epithelial cells. Thus, by implanting this membrane to the damaged periodontal tissue, bone regeneration will take place and integrity of periodontal tissues will be preserved.

A completely human-derived biomaterial mimicking limbal niche: Platelet-rich fibrin gel.

Platelet-rich fibrin (PRF) is a natural biomaterial and has excellent biochemical and physical properties with a history of proven biocompatibility in the field of tissue engineering and regenerative medicine. Recent reports of fibrin-based matrices have offered new opportunities to apply PRF as a supplement for in vitro cell culture. Here, custom-modified human-derived PRF (HPRF) was produced via different centrifugation protocols, then, characterized by morphologically and chemically and utilized as a substrate and as a conditioned medium for limbal explant culture for the first time. It was found that the HPRF released significantly higher levels of growth factors which are essential for epithelial cell growth. The enhanced physicochemical properties of the HPRF were also proven in the limbal explant cultures in terms of cell growth, migration, viability, and stemness in comparison with the conventional limbal explant culture on human-derived amniotic membrane. Consequently, HPRF hydrogels are appealing natural biomaterials for the purpose of mimicking limbal niche and the discovery elucidates this new, xeno-chemical-free, completely human-derived biomaterial can be utilized as a supplement to promote epithelial cell behaviour in vitro.

Photostimulation of osteogenic differentiation on silk scaffolds by plasma arc light source.

Low-level laser therapy (LLLT) has been used for more than 30 years to heal wounds. In recent years, LLLT or photostimulation has been indicated as an effective tool for regenerative and dental medicine by using monochromatic light. The aim of this study is to indicate the usability of plasma arc light source for bone regeneration. This is why we used polychromatic light source providing effective wavelengths in the range of 590-1500 nm for cellular response and investigated photostimulation effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) seeded on 3D silk scaffolds. Cellular responses were examined by using cell culture methods in terms of proliferation, differentiation, and morphological analyses. The results showed that photostimulation with a polychromatic light source (applied for 5 min from the 3rd day after seeding up to the 28th day in 2-day intervals with 92-mW/cm2 power from 10-cm distance to the cells) enhanced osteogenic differentiation of hMSCs according to higher alkaline phosphatase (ALP) activity, collagen and calcium content, osteogenic gene expressions, and matrix mineralization. In conclusion, we suggest that the plasma arc light source that was used here has a great potential for bone regeneration.

A Biomimetic Alternative to Synthetic Hydroxyapatite: "Boron-Containing Bone-Like Hydroxyapatite" Precipitated From Simulated Body Fluid.

BACKGROUND: Biological hydroxyapatite (HA), has several mechanical and physical advantages over the commercially available synthetic apatite (CAP-HA). The aim of this in vivo study was to investigate the effect of osteoinductive "bone-like hydroxyapatite" obtained from simulated body fluid (SBF) combined with osteoinductive "boron" (B) on bone healing. MATERIALS: Bone like nanohydroxyapatite (SBF-HA) was precipitated from 10× simulated body fluid (10×SBF). Thirty Sprague-Dawley rats were randomly divided into 5 experimental groups (n = 6 each). The groups were involving blank defect, chitosan, SBF-HA, SBF-HA/B, and CAP-HA. Two biparietal round critical sized bone defect was created using a dental burr. The rats were sacrificed respectively at the end of second and fourth months after surgery and their calvarium were harvested for further macroscopic, microtomographic, and histologic evaluation. RESULTS: The SBF-HA/B group demonstrated the highest mineralized matrix formation rates (30.69 ± 3.73 for the second month, 62.68 ± 7.03 for the fourth month) and was significantly higher than SBF-HA and the CAP-HA groups. The SBF-HA/B group demonstrated the highest mineralized matrix formation rates (30.69 ± 3.73 for the second month, 62.68 ± 7.03 for the fourth month) and was significantly higher than SBF-HA and the CAP-HA groups. In means of bone defect repair histologically, the highest result was observed in the SBF-HA/B group (P < 0.001). CONCLUSIONS: The "bone-like hydroxapatite" obtained from simulated body fluid is worth attention when both its beneficial effects on bone healing and its biological behavior is taken in consideration for further bone tissue engineering studies. It appears to be a potential alternative to the commercially available hydroxyapatite samples.

Combined delivery of PDGF-BB and BMP-6 for enhanced osteoblastic differentiation.

Natural microenvironment during bone tissue regeneration involves integration of multiple biological growth factors which regulate mitogenic activities and differentiation to induce bone repair. Among them platelet derived growth factor (PDGF-BB) and bone morphogenic protein-6 (BMP-6) are known to play a prominent role. The aim of this study was to investigate the benefits of combined delivery of PDGF-BB and BMP-6 on proliferation and osteoblastic differentiation of MC3T3-E1 preosteoblastic cells. PDGF-BB and BMP-6 were loaded in gelatin and poly (3-hydroxybutyric acid-co-3-hydroxyvaleric acid) particles, respectively. The carrier particles were then loaded into 3D chitosan matrix fabricated by freeze drying. The fast release of PDGF-BB during 7 days was accompanied by slower and prolonged release of BMP-6. The premising release of mitogenic factor PDGF-BB resulted in an increased MC3T3-E1 cell population seeded on chitosan scaffolds. Osteogenic markers of RunX2, Col 1, OPN were higher on chitosan scaffolds loaded with growth factors either individually or in combination. However, OCN expression and bone mineral formation were prominent on chitosan scaffolds incorporating PDGF-BB and BMP-6 as a combination.

Polychromatic light-induced osteogenic activity in 2D and 3D cultures.

Photobiomodulation (PBM) has been applied to manipulate cellular responses by using monochromatic light in different wavelengths from ultraviolet (UV) to infrared (IR) region. Until now, an effective wavelength has not been revealed to induce proliferation and/or differentiation of cells. Therefore, in the presented study, we decided to use a specially designed plasma arc light source providing wavelengths between 590 and 1500 nm in order to investigate its biomodulatory effects on chitosan scaffold-supported three-dimensional (3D) cell cultures. For comparison, two-dimensional (2D) cell cultures were also carried out in tissue-culture polystyrene dishes (TCPS). The results showed that light-induced temperature rise did not affect cells when the distance between the light source and the cells was 10 cm and the frequency of administration was daily. Moreover, light was applied for 5 and 10 min to the cells in TCPS and in chitosan scaffold groups, respectively. Cell culture studies under static conditions indicated that polychromatic light significantly stimulated bone nodule formation via the prolonged cell survival and stimulated differentiation of MC3T3-E1 preosteoblastic cells in both TCPS and chitosan scaffold groups. In conclusion, specially designed plasma arc light source used in this study induces formation of bone tissue and so, this light source is proposed as an appropriate system for in vitro bone tissue engineering applications. Statistical analyses were performed with one-way ANOVA by using GraphPad Instat software and standard deviations were calculated by using data of three parallel samples for each group.

Melatonin releasing PLGA micro/nanoparticles and their effect on osteosarcoma cells.

Melatonin loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles and microparticles in the diameter of ∼200 nm and 3.5 µm, respectively, were prepared by emulsion-diffusion-evaporation method. Melatonin entrapment into the particles was significantly improved with the addition of 0.2% (w/v) melatonin into the aqueous phase and encapsulation efficiencies were found as 14 and 27% for nanoparticles and microparticles, respectively. At the end of 40 days, ∼70% of melatonin was released from both of particles, with high burst release. Both blank and melatonin loaded PLGA nanoparticles caused toxic effect on the MG-63 cells due to their uptake by the cells. However, when 0.05 mg microparticle that is carrying ∼1.7 µg melatonin was added to the cm(2) of culture, inhibitory effect of melatonin on the cells were obviously observed. The results would provide an expectation about the usage of melatonin as an adjunct to the routine chemotherapy of osteosarcoma by encapsulating it into a polymeric carrier system.

Sustained release of 17ß-estradiol stimulates osteogenic differentiation of adipose tissue-derived mesenchymal stem cells on chitosan-hydroxyapatite scaffolds.

The aim of this study was to develop a 17ß-estradiol (E2)-releasing scaffold-nanoparticle system in order to promote osteogenic differentiation of rat adipose tissue-derived mesenchymal stem cells (AdMSCs) for bone tissue regeneration. E2-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles with a diameter of ∼240 nm were produced via an emulsion-diffusion-evaporation method. Because of its higher encapsulation efficiency (54%), PLGA, which has a 65:35 composition, was chosen for the preparation of nanoparticles. Chitosan-hydroxyapatite (HA) scaffolds in macroporous structures with interconnected pores were prepared by combining microwave irradiation and gas-foaming techniques. PLGA nanoparticles were loaded onto scaffolds in 2 ways: via embedding after scaffold fabrication and during fabrication. While 100% of the loaded E2 was released during 55 days from scaffolds loaded by embedding, a controlled release behavior of E2 was observed over 135 days in scaffolds loaded during manufacture. The results of cell culture studies indicated that the controlled delivery of E2 from PLGA nanoparticles loaded on chitosan-HA scaffolds had a significant effect on the osteogenic differentiation of AdMSCs.

Double-effective chitosan scaffold-PLGA nanoparticle system for brain tumour therapy: in vitro study.

The chitosan scaffold, which has both of anticancer and antivascularization effects, was developed for using in local therapy of brain tumours. This is why, poly-lactic-co-glycolic acid (50:50) nanoparticles (~200 nm) including an anticancer drug, 5-fluorouracil (5-FU), were prepared by emulsion-solvent evaporation method. Then, these nanoparticles and antivascularization agent, bevacizumab, were loaded into the scaffold during manufacturing by freeze-drying and embedding after freeze-drying, respectively. The idea behind this system is to destroy tumour tissue by releasing 5-FU and to prevent the proliferation of tumour cells by releasing bevacizumab. In addition, 3D scaffold can support healthy tissue formation in the tumourigenic region. In vitro effectiveness of this system was investigated on T98G human glioblastoma cell line and human umbilical vein endothelial cells. The results show that the chitosan scaffold containing 100 µg 5-FU and 100 µg bevacizumab has a potential to prevent the tumour formation in vitro conditions.

Polymer-clay nanofibrous wound dressing materials containing different boron compounds.

BACKGROUND: Montmorillonite (MMT) is a biocompatible nanoclay and its incorporation into polymeric matrix not only improves the polymer's wettability/biodegradability, but also enhances cellular proliferation, and differentiation. On the other hand, the positive effect of boron (B) on the healing cascade and its antibacterial properties have drawn the attention of researchers. MATERIALS & METHODS: In this regard, B compounds in different chemical structures, boron nitride (BN), zinc borate (ZB), and phenylboronic acid (PBA), were adsorbed onto MMT and then, poly (lactic acid) (PLA) based MMT/B including micron/submicron fibers were fabricated by electrospinning. RESULTS: The incorporation of MMT nanoparticles into the PLA demonstrated a porous fiber topography with enhanced thermal properties, water uptake capacity, and antibacterial effect. Furthermore, the composites including BN, ZB, and PBA showed bacteriostatic effects against Gram-negative and Gram-positive pathogenic bacteria (Escherichia coli and Staphylococcus aureus). In-vitro cell culture studies performed with human dermal fibroblasts (HDF) indicated the non-toxic effect of B compounds. The results showed that incorporation of MMT supported cell adhesion and proliferation, and further addition of B compounds especially PBA increased cell viability for 14 days. CONCLUSION: The results illustrated the acceptable characteristics of the B-containing composites and their favorable effect on the cells, demonstrating their potential as a skin tissue engineering product.

Investigation of healing strategies in a rat corneal opacity model with polychromatic light and stem cells injection.

Corneal opacities are a major cause of vision loss worldwide. However, the current therapies are suboptimal to manage the corneal wound healing process. Therefore, there is an obvious need to develop new treatment strategies that are efficient in promoting wound healing in patients with severe corneal disorders. In this study, we investigated and compared the efficacy of adipose-derived mesenchymal stem cells (ADMSCs) and photobiomodulation (PBM) with polychromatic light in the NIR (600-1200 nm) alone and in combination, on corneal opacity, inflammatory response, and tissue architecture in a rat corneal opacity model created by mechanical injury. All animals were divided into four groups randomly following the injury: injury only (no treatment), ADMSCs treatment, PBM treatment and combined (ADMSCs+PBM) treatment (n = 12 eyes per group). At the 10th and 30th day following injury, corneal opacity formation, neovascularization, and corneal thickness were assessed. On the 30th day the harvested corneas were analyzed by transmission electron microscopy (TEM), histological evaluation, immunohistochemical (IHC) staining and real-time polymerase chain reaction (RT-PCR). On day 30, the corneal opacity score, neovascularization grade, and corneal thickness in all treatment groups were significantly lower in comparison with the untreated injured corneas. The TEM imaging and H&E staining together clearly revealed a significant enhancement in corneal regeneration with improved corneal microenvironment and reduced vascularization in the combined administration of PBM and ADMSCs compared to treatment of PBM and ADMSCs alone. In addition, the IHC staining, and RT-PCR analysis supported our hypothesis that combining ADMSCs therapy with PBM alleviated the inflammatory response, and significantly decreased scar formation compared to either ADMSCs or PBM alone during the corneal wound healing.

Organomodified nanoclay with boron compounds is improving structural and antibacterial properties of nanofibrous matrices.

In this study, nanofibrous polymeric matrices were successfully developed with nanoclay, montmorillonite (MMT) and various boron (B) compounds, which were known to have positive effects on the wound healing with elevated antibacterial properties. For this purpose, MMT was modified with quaternary ammonium salt, trimethyl octadecyl ammonium bromide (TMOD), and boron compounds, boron nitride (BN), zinc borate (ZB), or phenylboronic acid (PBA) were adsorbed on organomodified MMT (OMMT). Then, poly (lactic acid) (PLA) based nanofibrous PLA-OMMT/B composites were fabricated via electrospinning. Modification of MMT nanoparticles with TMOD occurred through ion-exchange reaction and led to better homogenous fibrous structures which exhibited dramatic inhibition for gram-positive bacteria. Moreover, composites with ZB and PBA demonstrated both bacteriostatic and bactericidal effects for gram-positive and gram-negative bacteria. The chemical structures of the matrices were evaluated through ATR-FTIR and supported the intercalated composite formation. The thermal and mechanical stabilities of PLA matrices were also enhanced after OMMT and B incorporation. The lowest breaking strain value was recorded for PLA-OMMT/PBA composite compared to other B composites. The 100% and 50% extracts of the PLA-OMMT matrices showed modest cytotoxic effect on the human dermal fibroblasts (NHDF) on the second day culture that probably originated from TMOD. These results demonstrated that PLA-OMMT/B matrices, especially PBA including matrices, can be used as replaceable wound dressings that have limited interaction with cells but exhibit antibacterial activity and support the early stages of wound healing both morphologically and chemically.