Phenolated alginate hydrogel induced osteogenic properties of mesenchymal stem cells via Wnt signaling pathway.

Osteogenic properties of phenolated alginate (1.2 %) hydrogel containing collagen (0.5 %)/nano-hydroxyapatite (1 %) were studied on human mesenchymal stem cells in vitro. The phenolation rate and physical properties of the hydrogel were assessed using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), swelling ratio, gelation time, mechanical assay, and degradation rate. The viability of encapsulated cells was monitored on days 7, 14, and 21 using an MTT assay. Osteoblast differentiation was studied using western blotting, and real-time PCR. Using PCR array analysis, the role of the Wnt signaling pathway was also investigated. Data showed that the combination of alginate/collagen/nanohydroxyapatite yielded proper mechanical features. The addition of nanohydroxyapatite, and collagen reduced degradation, swelling rate coincided with increased stiffness. Elasticity and pore size were also diminished. NMR and FTIR revealed suitable incorporation of collagen and nanohydroxyapatite in the structure of alginate. Real-time PCR analysis and western blotting indicated the expression of osteoblast-related genes such as Runx2 and osteocalcin. PCR array revealed the induction of numerous genes related to Wnt signaling pathways during the maturation of human stem cells toward osteoblast-like cells. In vivo data indicated that transplantation of phenolated alginate/collagen/nanohydroxyapatite hydrogel led to enhanced de novo bone formation in rats with critical-sized calvarial defects. Phenolated alginate hydrogel can promote the osteogenic capacity of human amniotic membrane mesenchymal stem cells in the presence of nanohydroxyapatite and collagen via engaging the Wnt signaling pathway.

mTOR signalling pathway in stem cell bioactivities and angiogenesis potential.

The mammalian target of rapamycin (mTOR) is a protein kinase that responds to different stimuli such as stresses, starvation and hypoxic conditions. The modulation of this effector can lead to the alteration of cell dynamic growth, proliferation, basal metabolism and other bioactivities. Considering this fact, the mTOR pathway is believed to regulate the diverse functions in several cell lineages. Due to the pleiotropic effects of the mTOR, we here, hypothesize that this effector can also regulate the bioactivity of stem cells in response to external stimuli pathways under physiological and pathological conditions. As a correlation, we aimed to highlight the close relationship between the mTOR signalling axis and the regenerative potential of stem cells in a different milieu. The relevant publications were included in this study using electronic searches of the PubMed database from inception to February 2023. We noted that the mTOR signalling cascade can affect different stem cell bioactivities, especially angiogenesis under physiological and pathological conditions. Modulation of mTOR signalling pathways is thought of as an effective strategy to modulate the angiogenic properties of stem cells.

Review of ovarian tissue cryopreservation techniques for fertility preservation.

Ovarian failure and ovarian malfunction are among major fertility problems in women of reproductive age (18-35 years). It is known that various diseases, such as ovarian cancer and premature ovarian failure, besides certain treatments, such as radiotherapy and chemotherapy of other organs, can affect the normal process of folliculogenesis and cause infertility. In recent years, various procedures have been proposed for the treatment of infertility. One of the newest methods is the use of cryopreservation ovarian fragments after cancer treatment. According to some studies, this method yields very satisfactory results. Although ovarian tissue cryopreservation (OTC) is an accepted technique of fertility preservation, the relative efficacy of cryopreservation protocols remains controversial. Considering the controversies about these methods and their results, in this study, we aimed to compare different techniques of ovarian cryopreservation and investigate their advantages and disadvantages. Reviewing the published articles may be possible to identify appropriate strategies and improve infertility treatment in these patients.

Tissue Engineering Strategies to Increase Osteochondral Regeneration of Stem Cells; a Close Look at Different Modalities.

The homeostasis of osteochondral tissue is tightly controlled by articular cartilage chondrocytes and underlying subchondral bone osteoblasts via different internal and external clues. As a correlate, the osteochondral region is frequently exposed to physical forces and mechanical pressure. On this basis, distinct sets of substrates and physicochemical properties of the surrounding matrix affect the regeneration capacity of chondrocytes and osteoblasts. Stem cells are touted as an alternative cell source for the alleviation of osteochondral diseases. These cells appropriately respond to the physicochemical properties of different biomaterials. This review aimed to address some of the essential factors which participate in the chondrogenic and osteogenic capacity of stem cells. Elements consisted of biomechanical forces, electrical fields, and biochemical and physical properties of the extracellular matrix are the major determinant of stem cell differentiation capacity. It is suggested that an additional certain mechanism related to signal-transduction pathways could also mediate the chondro-osteogenic differentiation of stem cells. The discovery of these clues can enable us to modulate the regeneration capacity of stem cells in osteochondral injuries and lead to the improvement of more operative approaches using tissue engineering modalities.

Superior Synaptogenic Effect of Electrospun PLGA-PEG Nanofibers Versus PLGA Nanofibers on Human Neural SH-SY5Y Cells in a Three-Dimensional Culture System.

Synapses are touted as the main structural and functional components of neural cells within in the nervous system, providing tissue connectivity and integration via the formation of perineuronal nets. In the present study, we evaluated the synaptogenic activity of electrospun PLGA and PLGA-PEG nanofibers on human SH-SY5Y cells after 14 days in vitro. Electrospun PLGA and PLGA-PEG nanofibers were fabricated and physicochemical properties were examined using the HNMR technique. The cells were classified into three random groups, i.e., control (laminin-coated surface), PLGA, and PLGA-PEG. Scaffolds' features, cell morphology, attachment, and alignment were monitored by SEM imaging. We performed MTT assay to measure cell survival rate. To evaluate neurite formation and axonal outgrowth, cells were stained with an antibody against ß-tubulin III using immunofluorescence imaging. Antibodies against synapsin-1 and synaptophysin were used to explore the impact of PLGA and PLGA-PEG scaffolds on synaptogenesis and functional activity of synapses. According to SEM analysis, the PLGA-PEG scaffold had less thick nanofibers compared with the PLGA scaffold. Cell attachment, expansion, neurite outgrowth, and orientation were promoted in the PLGA-PEG group in comparison with the PLGA substrate (p < 0.05). MTT assay revealed that both scaffolds did not exert any neurotoxic effects on cell viability. Notably, PLGA-PEG surface increased cell viability compared to PLGA by time (p < 0.05). Immunofluorescence staining indicated an increased ß-tubulin III level in the PLGA-PEG group days coincided with axonal outgrowth and immature neuron marker after seven compared with the PLGA and control groups (p < 0.05). Based on our data, both synaptogenesis and functional connectivity were induced in cells plated on the PLGA-PEG surface that coincide with the increase of synapsin-1 and synaptophysin in comparsion with the PLGA and control groups (p < 0.05). Taken together, our results imply that the PLGA-PEG nanofibers could provide the desirable microenvironment to develop perineuronal net formation, contributing to efficient synaptogenesis and neuron-to-neuron crosstalk.

The Application of Hydrogels Based on Natural Polymers for Tissue Engineering.

Hydrogels are known as polymer-based networks with the ability to absorb water and other body fluids. Because of this, the hydrogels are used to preserve drugs, proteins, nutrients or cells. Hydrogels possess great biocompatibility, and properties like soft tissue, and networks full of water, which allows oxygen, nutrients, and metabolites to pass. Therefore, hydrogels are extensively employed as scaffolds in tissue engineering. Specifically, hydrogels made of natural polymers are efficient structures for tissue regeneration, because they mimic natural environment which improves the expression of cellular behavior. Producing natural polymer-based hydrogels from collagen, hyaluronic acid (HA), fibrin, alginate, and chitosan is a significant tactic for tissue engineering because it is useful to recognize the interaction between scaffold with a tissue or cell, their cellular reactions, and potential for tissue regeneration. The present review article is focused on injectable hydrogels scaffolds made of biocompatible natural polymers with particular features, the methods that can be employed to engineer injectable hydrogels and their latest applications in tissue regeneration.

Retraction Note to: Synthesis, characterization and in vitro studies of doxorubicin-loaded magnetic nanoparticles grafted to smart copolymers on A549 lung cancer cell line.

The Editors have retracted this article [1] because Figs. 6a and 6c have been used in three other publications to represent scanning electron micrographs of different nanoparticles [2-4]. The data reported in this article are therefore unreliable. In addition, Fig. 3 was reproduced from [5] with retrospective permission and the credit line should read as follows: "Reprinted from Acta Biomaterialia, Volume 3, Zhang, J. and Misra, R.D.K., Magnetic drug-targeting carrier encapsulated with thermosensitive smart polymer: core-shell nanoparticle carrier and drug release response, pp. 838-850, copyright (2007) with permission from Acta Materialia Inc. Authors Abolfazl Akbarzadeh, Maryam Anzaby, Soodabeh Davaran, Sang Woo Joo and Mohammad Samiei agree to this retraction. Authors Younes Hanifehpour and Hamid Tayefi Nasrabadi have not responded to any correspondence about this retraction.

Copper sulfate pentahydrate reduced epithelial cytotoxicity induced by lipopolysaccharide from enterogenic bacteria.

The over usage of multiple antibiotics contributes to the emergence of a whole range of antibiotic-resistant strains of bacteria causing enterogenic infections in poultry science. Therefore, finding an appropriate alternative natural substance carrying an antibacterial capacity would be immensely beneficial. It has been previously discovered that the different types of cupric salts, especially copper sulfate pentahydrate (CuSO4·5H2O), to carry a potent bactericidal capacity. We investigated the neutralizing effect of CuSO4·5H2O (6.25µg/ml) on the reactive oxygen species generation, and expression of MyD88, an essential adaptor protein of Toll-like receptor, and NF-κB in three intestinal epithelial cell lines exposed to 50ng/ml lipopolysaccharide. In order to find the optimal cupric sulfate concentration without enteritis-inducing toxicity, broiler chickens were initially fed with water containing 0.4, 0.5, and 1mg/l during a period of 4days. After determination of appropriate dosage, two broiler chickens and turkey flocks with enteritis were fed with cupric compound for 4days. We found that cupric sulfate can lessen the cytotoxic effect of lipopolysaccharide by reducing the reactive oxygen species content (p<0.05). Additionally, the expression of MyD88 and NF-κB was remarkably down-regulated in the presence of lipopolysaccharide and cupric sulfate. The copper sulfate in doses lower than 0.4mg/ml expressed no cytotoxic effect on the liver, kidney, and the intestinal tract while a concentration of 0.5 and 1mg/ml contributed to a moderate to severe tissue injuries. Pearson Chi-Square analysis revealed the copper cation significantly diminished the rate of mortality during 4-day feeding of broiler chicken and turkey with enteritis (p=0.000). Thus, the results briefed above all confirm the potent anti-bactericidal feature of cupric sulfate during the course of enteritis.

A variation of Musculocutaneous nerve without piercing the coracobrachialis muscle while communicating to the median nerve: A case report and literature review.

INTRODUCTION: Anatomical variations of the peripheral nervous system may have not any clinical signs and symptoms. One of these variations belongs to the Musculocutaneous nerve. However, a good knowledge of nerve pathways and their variations is very important for surgeons in post-traumatic evaluations, exploratory interventions, and/or administration of neuromuscular blocks in axillary region in order to surgical therapies. PRESENTATION OF CASE: This report describes a case of variation of the musculocutaneous nerve which was observed in an old Iranian male cadaver during routine educational dissection (Fig. 1). DISCUSSION AND CONCLUSION: Anatomically, in the axilla region, the Musculocutaneous nerve is originated of the lateral cord of brachial plexus, then, by piercing the coracobrachialis muscle arrives enters to anterior compartment of the arm. But, in the present report, we observed that the Musculocutaneous nerve without piercing the coracobrachialis muscle has arrived in the left arm, then communicated to the Median nerve. To exploratory interventions of the arms for peripheral nerve repair and surgical therapies, a good knowledge of nerve pathways helps to surgeons for preventing possible mistakes during surgery.

Role of Probiotics in Managing of Helicobacter Pylori Infection: A Review.

Background:Helicobacter pylori is a prevalent pathogen which is considered as an etiological cause for gastroduodenal ulcers, and a substantial risk factor for gastric malignancies. The vital factor to take into account is that roughly half of the world's population is infected with this bacterium. However, most subjects colonized remain asymptomatic and do not require any treatment. Several antimicrobial agents such as amoxicillin, clarithromycin and metronidazole are used to eradicate the infection. However, these drug regiments do not eradicate H. pylori in all patients because of the anti-drug resistance. Aim: In this review we aim to discuss the role and mechanisms of probiotics, as supportive medicines, in management of H. pylori infection. Methods: We have reviewed the published articles in PubMed and Medline databases. Also, abstracts presented in international conferences on the management of H. pylori infections and treatment protocol, have been thoroughly reviewed. Results: The overall trend in the literature indicates the usefulness of probiotics in controlling H. pylori infection. This bacterium is among the most studied human pathogens regarding the efficacy of probiotics for treating its infection. Nevertheless, some studies suggest that probiotics do not efficiently eradicate H. pylori but retain the number of this bacterium at low levels inside the human stomach. Conclusion: The analyzed literature suggest that when probiotics are consumed in conjunction with antibiotics, the eradication rate may be improved through modulating the immune response and decreasing the adverse effects of routine drugs leading to gastroprotection.

Bimetallic nanoparticles: Preparation, properties, and biomedical applications.

Many studies of non-supported bimetallic nanoparticle (BMNP) dispersions, stabilized by ligands or polymers, and copolymers, were started only about 10 years ago. Several preparative procedures have been proposed, and full characterizations on BMNPs have been approved. Studies on BMNPs received huge attention from both scientific and technological communities because most of the NPs' catalytic activity depends on their structural aspects. In this study, we focus on the preparation, properties, and bio-application of BMNPs and introduction of the recent advance in these NPs.

Dendrimers: synthesis, applications, and properties.

Dendrimers are nano-sized, radially symmetric molecules with well-defined, homogeneous, and monodisperse structure that has a typically symmetric core, an inner shell, and an outer shell. Their three traditional macromolecular architectural classes are broadly recognized to generate rather polydisperse products of different molecular weights. A variety of dendrimers exist, and each has biological properties such as polyvalency, self-assembling, electrostatic interactions, chemical stability, low cytotoxicity, and solubility. These varied characteristics make dendrimers a good choice in the medical field, and this review covers their diverse applications.

Synthesis, characterization, and in vitro studies of PLGA-PEG nanoparticles for oral insulin delivery.

Therapeutic proteins and peptides are corresponding to a major area of research in biotechnology companies and current pharmaceutical. Because of their natural instability, the enormous majority of these drugs require parentéral administration. Oral insulin delivery would be a highly attractive alternative process of administration, though it continues to be a mysterious target due to the enzymatic digestion of insulin and low levels of absorption from the gastrointestinal region. Hydrogel polymers can be considered as potential carriers for oral insulin delivery. In particular, a pH responsive hydrogel composed of PLGA-PEG has shown the ability to protect insulin from enzymes in the gastric environment and release in small intestines. However, this material has not shown similar potential for oral protein delivery of further model drugs. To date, the unique interaction between PLGA-PEG and insulin, as a potential drug for oral delivery, is not completely understood. The focus of this research is synthetization and characterization of hydrogels PLGA-PEG insulin nanoparticles and also pH sensitivity of insulin nanoparticles was investigated.

Synthesis, characterization and in vitro studies of doxorubicin-loaded magnetic nanoparticles grafted to smart copolymers on A549 lung cancer cell line.

BACKGROUND: The aim of present study was to develop the novel methods for chemical and physical modification of superparamagnetic iron oxide nanoparticles (SPIONs) with polymers via covalent bonding entrapment. These modified SPIONs were used for encapsulation of anticancer drug doxorubicin. METHOD: At first approach silane-grafted magnetic nanoparticles was prepared and used as a template for polymerization of the N-isopropylacrylamide (NIPAAm) and methacrylic acid (MAA) via radical polymerization. This temperature/pH-sensitive copolymer was used for preparation of DOX-loaded magnetic nanocomposites. At second approach Vinyltriethoxysilane-grafted magnetic nanoparticles were used as a template to polymerize PNIPAAm-MAA in 1, 4 dioxan and methylene-bis-acrylamide (BIS) was used as a cross-linking agent. Chemical composition and magnetic properties of Dox-loaded magnetic hydrogel nanocomposites were analyzed by FT-IR, XRD, and VSM. RESULTS: The results demonstrate the feasibility of drug encapsulation of the magnetic nanoparticles with NIPAAm-MAA copolymer via covalent bonding. The key factors for the successful prepardtion of magnetic nanocomposites were the structure of copolymer (linear or cross-linked), concentration of copolymer and concentration of drug. The influence of pH and temperature on the release profile of doxorubicin was examined. The in vitro cytotoxicity test (MTT assay) of both magnetic DOx-loaded nanoparticles was examined. The in vitro tests showed that these systems are no toxicity and are biocompatible. CONCLUSION: IC50 of DOx-loaded Fe3O4 nanoparticles on A549 lung cancer cell line showed that systems could be useful in treatment of lung cancer.