Seyed Mahdi Rezayat Sorkhabadi

Bio: Seyed Mahdi Rezayat Sorkhabadi is an academic researcher from Tehran University of Medical Sciences. The author has contributed to research in topics: Bone regeneration & Molecularly imprinted polymer. The author has an hindex of 10, co-authored 22 publications receiving 271 citations. Previous affiliations of Seyed Mahdi Rezayat Sorkhabadi include Islamic Azad University.

Mechano-Transduction Signals Derived from Self-Assembling Peptide Nanofibers Containing Long Motif of Laminin Influence Neurogenesis in In-Vitro and In-Vivo.

Abstract: Astroglial scaring and limited neurogenesis are two problematic issues in recovery of spinal cord injury (SCI). In the meantime, it seems that mechanical manipulations of scaffold to inhibit astroglial scarring and improve neurogenesis is worthy of value. In the present investigation, the effect of nanofiber (gel) concentration as a mechanical-stimuli in neurogenesis was investigated. Cell viability, membrane damage, and neural differentiation derived from endometrial stem cells encapsulated into self-assembling peptide nanofiber containing long motif of laminin were assessed. Then, two of their concentrations that had no significant difference of neural differentiation potential were selected for motor neuron investigation in SCI model of rat. MTT assay data showed that nanofibers at the concentrations of 0.125 and 0.25 % w/v induced higher and less cell viability than others, respectively, while cell viability derived from higher concentrations of 0.25 % w/v had ascending trend. Gene expression results showed that noggin along with laminin motif over-expressed TH gene and the absence of noggin or laminin motif did not in all concentrations. Bcl2 over-expression is concomitant with the decrease of nanofiber stiffness, NF+ cells increment, and astrogenesis inhibition and dark neuron decrement in SCI model. It seems that stiffness affects on Bcl2 gene expression and may through β-Catenin/Wnt signaling pathway and BMP-4 inhibition decreases astrogenesis and improves neurogenesis. However, stiffness had a significant effect on upregulation of GFAP+ cells and motor neuron recovery in in vivo. It might be concluded that eventually there is a critical definitive point concentration that at less or higher than of it changes cell behavior and neural differentiation through different molecular pathways.

Tumor-associated macrophages and epithelial-mesenchymal transition in cancer: Nanotechnology comes into view

Abstract: Tumor-associated macrophages (TAMs) are an important component of the leukocytic infiltrate of the tumor microenvironment. There is persuasive preclinical and clinical evidence that TAMs induce cancer inanition and malignant progression of primary tumors toward a metastatic state through a highly conserved and fundamental process known as epithelial-mesenchymal transition (EMT). Tumor cells undergoing EMT are distinguished by increased motility and invasiveness, which enable them to spread to distant sites and form metastases. In addition, besides becoming resistant to apoptosis and antitumor drugs, they also contribute to immunosuppression and get a cancer stem-cell like phenotype. Here, we will focus on selected molecular pathways underlying EMT-in particular, the role of TAMs in the induction and maintenance of EMT-and further discuss how the targeting of TAMs through the application of nanotechnology tools allows the development of a whole new range of therapeutics.

Development and physicochemical, toxicity and immunogenicity assessments of recombinant hepatitis B surface antigen (rHBsAg) entrapped in chitosan and mannosylated chitosan nanoparticles: as a novel vaccine delivery system and adjuvant.

Abstract: In this study chitosan nanoparticles (CS NPs) and mannosylated chitosan nanoparticles (MCH NPs) loaded with recombinant hepatitis B surface antigen (rHBsAg) was synthesized as a vaccine delivery system and assessed toxically and immunologically. The physicochemical properties of the nanoparticles (NPs) were determined by methods including scanning electron microscope (SEM) and dynamic light scattering (DLS). The morphology of the NPs was semi spherical and the average diameter of the loaded CS and MCH NPs was found to be 189 and 239 nm, respectively. The release studies showed that after the initial burst, both of the loaded NPs provided a continuous and slow release of the antigens. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed concentration and time dependent toxicity profile for both formulations, but rHBsAg loaded CS nanoparticle showed higher toxicity due to smaller particle size and larger zeta potential. Abnormal toxicity test (ATT) results showed no signs of toxicity in mice and guinea-pigs treated with loaded MCHNPs. Stability test for six months showed acceptable changes in size, surface charge, and antigenicity for loaded MCH nanoparticles. Finally, in vivo immunogenicity study revealed greater adjuvant capability of MCH nanoparticles than others formulations. Our results showed MCH NPs can be used as a controlled and targeted vaccine delivery system.

Bone regenerative medicine: classic options, novel strategies, and future directions

Abstract: This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.

The epigenetics of epithelial-mesenchymal plasticity in cancer

Abstract: Epithelial-mesenchymal transitions (EMTs) are a key requirement for cancer cells to metastasize and colonize in a new environment. Epithelial-mesenchymal plasticity is mediated by master transcription factors and is also subject to complex epigenetic regulation. This Review outlines our current understanding of the interactions between EMT-inducing transcription factors and epigenetic modulators during cancer progression and the therapeutic implications of exploiting this intricate regulatory process. During the course of malignant cancer progression, neoplastic cells undergo dynamic and reversible transitions between multiple phenotypic states, the extremes of which are defined by the expression of epithelial and mesenchymal phenotypes. This plasticity is enabled by underlying shifts in epigenetic regulation. A small cohort of pleiotropically acting transcription factors is widely recognized to effect these shifts by controlling the expression of a constituency of key target genes. These master regulators depend on complex epigenetic regulatory mechanisms, notably the induction of changes in the modifications of chromatin-associated histones, in order to achieve the widespread changes in gene expression observed during epithelial-mesenchymal transitions (EMTs). These associations indicate that an understanding of the functional interactions between such EMT-inducing transcription factors and the modulators of chromatin configuration will provide crucial insights into the fundamental mechanisms underlying cancer progression and may, in the longer term, generate new diagnostic and therapeutic modalities for treating high-grade malignancies.

Progress in enzyme immobilization in ordered mesoporous materials and related applications

Abstract: A short time after the discovery of ordered mesoporous materials, which possess unique features such as high specific surface area and pore volume, highly uniform pore distribution and tunable pore size, these materials have been prospected as promising carriers for enzyme immobilization. The immobilization of enzymes in ordered mesoporous materials has been studied for almost two decades. With the development of tailored ordered mesoporous materials and advances in enzyme technology, this field attracted increasing interest due to its quickly expanded functions and applications. This review focuses on the relation between the progress in ordered mesoporous materials and its corresponding contribution to enzyme immobilization as well as the applications of these materials in biocatalysis. The potential trends in the future development of this field are also pointed out.

Necrotic, apoptotic and autophagic cell fates triggered by nanoparticles

Abstract: Nanomaterials have gained a rapid increase in use in a variety of applications that pertain to many aspects of human life. The majority of these innovations are centered on medical applications and a range of industrial and environmental uses ranging from electronics to environmental remediation. Despite the advantages of NPs, the knowledge of their toxicological behavior and their interactions with the cellular machinery that determines cell fate is extremely limited. This review is an attempt to summarize and increase our understanding of the mechanistic basis of nanomaterial interactions with the cellular machinery that governs cell fate and activity. We review the mechanisms of NP-induced necrosis, apoptosis and autophagy and potential implications of these pathways in nanomaterial-induced outcomes. Abbreviations: Ag, silver; CdTe, cadmium telluride; CNTs, carbon nanotubes; EC, endothelial cell; GFP, green fluorescent protein; GO, graphene oxide; GSH, glutathione; HUVECs, human umbilical vein endothelial cells; NP, nanoparticle; PEI, polyethylenimine; PVP, polyvinylpyrrolidone; QD, quantum dot; ROS, reactive oxygen species; SiO2, silicon dioxide; SPIONs, superparamagnetic iron oxide nanoparticles; SWCNT, single-walled carbon nanotubes; TiO2, titanium dioxide; USPION, ultra-small super paramagnetic iron oxide; ZnO, zinc oxide.

Nanomaterials for Wound Healing and Infection Control.

Abstract: Wound healing has been intensely studied in order to develop an “ideal” technique that achieves expeditious recovery and reduces scarring to the minimum, thus ensuring function preservation. The classic approach to wound management is represented by topical treatments, such as antibacterial or colloidal agents, in order to prevent infection and promote a proper wound-healing process. Nanotechnology studies submicroscopic particles (maximum diameter of 100 nm), as well as correlated phenomena. Metal nanoparticles (e.g., silver, gold, zinc) are increasingly being used in dermatology, due to their beneficial effect on accelerating wound healing, as well as treating and preventing bacterial infections. Other benefits include: ease of use, less frequent dressing changes and a constantly moist wound environment. This review highlights recent findings regarding nanoparticle application in wound management.