A Combination of Physical and Chemical Treatments Is More Effective in The Preparation of Acellular Uterine Scaffolds.

OBJECTIVE: Decellularized uterine scaffold, as a new achievement in tissue engineering, enables recellularization and regeneration of uterine tissues and supports pregnancy in a fashion comparable to the intact uterus. The acellular methods are methods preferred in many respects due to their similarity to normal tissue, so it is necessary to try to introduce an acellularization protocol with minimum disadvantages and maximum advantages. Therefore, this study aimed to compare different protocols to achieve the optimal uterus decellularization method for future in vitro and in vivo bioengineering experiments. MATERIALS AND METHODS: In this experimental study, rat uteri were decellularized by four different protocols (P) using sodium dodecyl sulfate (SDS), with different doses and time incubations (P1 and P2), SDS/Triton-X100 sequentially (P3), and a combination of physical (freeze/thaw) and chemical reagents (SDS/Triton X-100). The scaffolds were examined by histopathological staining, DNA quantification, MTT assay, blood compatibility assay, FESEM, and mechanical studies. RESULTS: Histology assessment showed that only in P4, cell residues were completely removed. Masson's trichrome staining demonstrated that in P3, collagen fibers were decreased; however, no damage was observed in the collagen bundles using other protocols. In indirect MTT assays, cell viabilities achieved by all used protocols were significantly higher than the native samples. The percentage of red blood cell (RBC) hemolysis in the presence of prepared scaffolds from all 4 protocols was less than 2%. The mechanical properties of none of the obtained scaffolds were significantly different from the native sample except for P3. CONCLUSION: Uteri decellularized with a combination of physical and chemical treatments (P4) was the most favorable treatment in our study with the complete removal of cell residue, preservation of the three-dimensional structure, complete removal of detergents, and preservation of the mechanical property of the scaffolds.

Recent developments in SARS-CoV-2 vaccines: A systematic review of the current studies.

Designing and manufacturing efficient vaccines against coronavirus disease 2019 (COVID-19) is a major objective. In this systematic review, we aimed to evaluate the most important vaccines under construction worldwide, their efficiencies and clinical results in healthy individuals and in those with specific underlying diseases. We conducted a comprehensive search in PubMed, Scopus, EMBASE, and Web of Sciences by 1 December 2021 to identify published research studies. The inclusion criteria were publications that evaluated the immune responses and safety of COVID-19 vaccines in healthy individuals and in those with pre-existing diseases. We also searched the VAERS database to estimate the incidence of adverse events of special interest (AESI) post COVID-19 vaccination. Almost all investigated vaccines were well tolerated and developed good levels of both humoural and cellular responses. A protective and efficient humoural immune response develops after the second or third dose of vaccine and a longer interval (about 28 days) between the first and second injections of vaccine could induce higher antibody responses. The vaccines were less immunogenic in immunocompromised patients, particularly those with haematological malignancies. In addition, we found that venous and arterial thrombotic events, Bell's palsy, and myocarditis/pericarditis were the most common AESI. The results showed the potency of the SARS-CoV-2 vaccines to protect subjects against disease. The provision of further effective and safe vaccines is necessary in order to reach a high coverage of immunisation programs across the globe and to provide protection against infection itself.

Modulation of the Immune System Promotes Tissue Regeneration.

The immune system plays an essential role in the angiogenesis, repair, and regeneration of damaged tissues. Therefore, the design of scaffolds that manipulate immune cells and factors in such a way that could accelerate the repair of damaged tissues, following implantation, is one of the main goals of regenerative medicine. However, before manipulating the immune system, the function of the various components of the immune system during the repair process should be well understood and the fabrication conditions of the manipulated scaffolds should be brought closer to the physiological state of the body. In this article, we first review the studies aimed at the role of distinct immune cell populations in angiogenesis and support of damaged tissue repair. In the second part, we discuss the use of strategies that promote tissue regeneration by modulating the immune system. Given that various studies have shown an increase in tissue repair rate with the addition of stem cells and growth factors to the scaffolds, and regarding the limited resources of stem cells, we suggest the design of scaffolds that are capable to develop repair of damaged tissue by manipulating the immune system and create an alternative for repair strategies that use stem cells or growth factors.

Fabrication and Characterization of Nanofibrous Poly (L-Lactic Acid)/Chitosan-Based Scaffold by Liquid-Liquid Phase Separation Technique for Nerve Tissue Engineering.

Fabrication method is one of the essential factors which directly affect on the properties of scaffold. Several techniques have been well established to fabricate nanofibrous scaffolds such as electrospinning. However, preparing a three-dimensional (3-D) interconnected macro-pore scaffold essential for transporting the cell metabolites and nutrients is difficult using the electrospinning method. The main aim of this study was developing a highly porous scaffold by poly (L-lactic acid) (PLLA)/chitosan blend using liquid-liquid phase separation (LLPS) technique, a fast and cost-benefit method, in order to use in nerve tissue engineering. In addition, the effect of different polymeric concentrations on morphology, mechanical properties, hydrophilicity, in vitro degradation rate and pH alteration of the scaffolds were evaluated. Moreover, cell attachment, cell viability and cell proliferation of scaffolds as candidates for nerve tissue engineering was investigated. PLLA/chitosan blend not only had desirable structural properties, porosity, hydrophilicity, mechanical properties, degradation rate and pH alteration but also provided a favorable environment for attachment, viability, and proliferation of human neuroblastoma cells, exhibiting significant potential for nerve tissue engineering applications. However, the polymeric concentration in blend fabrication had influence on both characteristics and cell responses. It concluded that PLLA/chitosan nanofibrous 3-D scaffold fabricated by LLPS method as a suitable candidate for nerve tissue engineering.

Advances in immunotherapy for COVID-19: A comprehensive review.

COVID-19 is an acute respiratory syndrome caused by SARS-COV-2 which has now become a huge pandemic worldwide. The immunopathogenesis of COVID-19 has been established that increased serum levels of C-reactive protein (CRP), interleukin-6 (IL-6), and reduction of the CD4+ and the CD8+ T lymphocyte populations, are the most reported immunological findings in these patients. High levels of other inflammatory cytokines and chemokines such as IL-2 and IL-8 with an increased number of neutrophils and eosinophils may induce immune abnormalities in patients with COVID-19. There is growing evidence to obtain a deeper understanding of the immunopathogenesis of COVID-19 which will lay the foundation for the development of new potential therapies. However, specific and non-specific immunotherapies such as convalescent plasma (CP) are widely performed to treat patients with severe COVID-19, there is no definitive evidence to suggest the effectiveness of these treatments. Hence, this review aimed to highlight the current and most recent studies to identify the new immunotherapeutics for COVID-19 disease.

Oxidative stress and anti-oxidant defense system in Iranian women with polycystic ovary syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common disorder of infertility which affects more than 100 million women. It is characterized by chronic anovulation, hyper androgenism and obesity. PCOS is also associated with oxidative stress changes. OBJECTIVE: Here, we aimed to investigate the level of antioxidants and oxidative stress in Iranian women with PCOS as a predictive factor for cardiovascular disease for the first time in Iran. MATERIALS AND METHODS: In this cross sectional study 30 women with PCOS and 30 healthy women were included. C-reactive protein, serum insulin, advanced oxidation protein products, and level of total antioxidants status were measured from blood samples. RESULTS: The levels of serum insulin, C-reactive protein, advanced oxidation protein productswere significantly increased in women with PCOS compared with healthy women but there was a decrease in level of total antioxidants status in PCOS women. CONCLUSION: These changes show that oxidative stress contributes to PCOS and the decrease of antioxidants leads to increase of oxidation products contributing to PCOS.