The effect of low-level laser therapy on pathophysiology and locomotor recovery after traumatic spinal cord injuries: a systematic review and meta-analysis.

This study was designed to determine the effective therapeutic parameters and evaluate the regenerative potential of low-level laser therapy (LLLT) after traumatic spinal cord injuries (TSCIs) in animal studies. The EMBASE and MEDLINE databases were searched on October 5, 2019, and followed with an update on January 2, 2021. All animal studies discussing the effect of LLLT on main pathophysiological events after TSCI, including inflammation, axon growth, remyelination, glial scar formation, cavity size, and locomotor recovery, were included. For statistical analysis, we used mean difference with 95% confidence intervals for locomotor recovery. In total, 19 articles were included based on our criteria. The results showed that regardless of laser type, laser beams with a wavelength between 600 and 850 nm significantly suppress inflammation and led inflammatory cells to M2 polarization and wound healing. Also, laser therapy using these wavelengths for more than 2 weeks significantly improved axon regeneration and remyelination. Improvement of locomotor recovery was more efficient using wavelengths less than 700 nm (SMD = 1.21; 95%CI: 0.09, 2.33; p = 0.03), lasers with energy densities less than 100 J/cm2 (SMD = 1.72; 95%CI: 0.84, 2.59; p = 0.0001) and treatment duration between 1 and 2 weeks (SMD = 2.21; 95%CI: 1.24, 3.19; p < 0.00001). The LLLT showed promising potential to modulate pathophysiological events and recovery after TSCI, although there was heterogeneity in study design and reporting methods, which should be considered in future studies.

Fabrication and evaluation of porous and conductive nanofibrous scaffolds for nerve tissue engineering.

Peripheral nerve repair is still one of the major clinical challenges which has received a great deal of attention. Nerve tissue engineering is a novel treatment approach that provides a permissive environment for neural cells to overcome the constraints of repair. Conductivity and interconnected porosity are two required characteristics for a scaffold to be effective in nerve regeneration. In this study, we aimed to fabricate a conductive scaffold with controlled porosity using polycaprolactone (PCL) and chitosan (Chit), FDA approved materials for the use in implantable medical devices. A novel method of using tetrakis (hydroxymethyl) phosphonium chloride (THPC) and formaldehyde was applied for in situ synthesis of gold nanoparticles (AuNPs) on the scaffolds. In order to achieve desirable porosity, different percentage of polyethylene oxide (PEO) was used as sacrificial fiber. Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FE-SEM) results demonstrated the complete removing of PEO from the scaffolds after washing and construction of interconnected porosities, respectively. Elemental and electrical analysis revealed the successful synthesis of AuNPs with uniform distribution and small average diameter on the PCL/Chit scaffold. Contact angle measurements showed the effect of porosity on hydrophilic properties of the scaffolds, where the porosity of 75-80% remarkably improved surface hydrophilicity. Finally, the effect of conductive nanofibrous scaffold on Schwann cells morphology and vaibility was investigated using FE-SEM and MTT assay, respectively. The results showed that these conductive scaffolds had no cytotoxic effect and support the spindle-shaped morphology of cells with elongated process which are typical of Schwann cell cultures.

Microtubule stabilizer epothilone B as a motor neuron differentiation agent for human endometrial stem cells.

Microtubule-stabilizing agents (MSAs), until now, have primarily been considered for their anti-proliferative effects in the setting of cancer. However, recent studies have revealed that one particular MSA, epothilone B (EpoB), can promote axonal regeneration after traumatic spinal cord injuries (SCI) even in the presence of inhibitor molecules such as neurite outgrowth inhibitor-A (Nogo-A). On the basis of the importance of having an efficient motor neuron (MN) differentiation protocol for stem cell therapy and the attention of MSAs for SCI treatment, our study investigated the effect of EpoB on human endometrial stem cells (hEnSCs) differentiation into MN-like cells. hEnSCs were isolated and characterized by flow cytometry. The hEnSC cell viability was evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To mimic the in vivo inhibitory environment, hEnSCs were also differentiated in the presence of Nogo-A. After 15 days of differentiation, the expressions of MN-markers were evaluated by real-time reverse-transcriptase polymerase chain reaction and immunofluorescence. According to the MTT assay results, three doses (1, 5, and 10 nM) of EpoB were selected to evaluate their effect on MN-differentiation. All selected doses can increase the efficacy of hEnSCs differentiation into MN-like cells. In particular, the 10 nM EpoB dosage was shown to increase the axon elongation, cell alignment, and upregulation of these MN-markers compared with other doses. EpoB can improve MN differentiation from hEnSC and potentially provide a unique route for neuronal replacement in the setting of SCI.

Fabrication and characterization of gold nanoparticle-doped electrospun PCL/chitosan nanofibrous scaffolds for nerve tissue engineering.

In the field of nerve tissue engineering, nanofibrous scaffolds could be a promising candidate when they are incorporated with electrical cues. Unique physico-chemical properties of gold nanoparticles (AuNPs) make them an appropriate component for increasing the conductivity of scaffolds to enhance the electrical signal transfer between neural cells. The aim of this study was fabrication of AuNPs-doped nanofibrous scaffolds for peripheral nerve tissue engineering. Polycaprolactone (PCL)/chitosan mixtures with different concentrations of chitosan (0.5, 1 and 1.5) were electrospun to obtain nanofibrous scaffolds. AuNPs were synthesized by the reduction of HAuCl4 using chitosan as a reducing/stabilizing agent. A uniform distribution of AuNPs with spherical shape was achieved throughout the PCL/chitosan matrix. The UV-Vis spectrum revealed that the amount of gold ions absorbed by nanofibrous scaffolds is in direct relationship with their chitosan content. Evaluation of electrical property showed that inclusion of AuNPs significantly enhanced the conductivity of scaffolds. Finally, after 5 days of culture, biological response of Schwann cells on the AuNPs-doped scaffolds was superior to that on as-prepared scaffolds in terms of improved cell attachment and higher proliferation. It can be concluded that the prepared AuNPs-doped scaffolds can be used to promote peripheral nerve regeneration.

Nanoshell-mediated targeted photothermal therapy of HER2 human breast cancer cells using pulsed and continuous wave lasers: an in vitro study.

In this study, we report the apoptosis induction in HER2 overexpressed breast cancer cells using pulsed, continuous wave lasers and polyvinylpyrrolidone (PVP)-stabilized magneto-plasmonic nanoshells (PVP-MPNS) delivered by immunoliposomes. The immunoliposomes containing PVP-MPNS were fabricated and characterized. Heating efficiency of the synthesized nanostructures was calculated. The effect of functionalization on cellular uptake of nanoparticles was assessed using two cell lines of BT-474 and Calu-6. The best uptake result was achieved by functionalized liposome (MPNS-LAb) and BT-474. Also, the interaction of 514 nm argon (Ar) and Nd/YAG second harmonic 532-nm lasers with nanoparticles was investigated based on the temperature rise of the nanoshell suspension and the release value of 5(6)-carboxyfluorescein (CF) from CF/MPNS-loaded liposomes. The temperature increase of the suspensions after ten consecutive pulses of 532 nm and 5 min of irradiation by Ar laser were measured approximately 2 and 12 °C, respectively. The irradiation of CF/MPNS-loaded liposomes by Ar laser for 3 min resulted in 24.3 % release of CF, and in the case of 532 nm laser, the release was laser energy dependent. Furthermore, the comparison of CF release showed a higher efficiency for the Ar laser than by direct heating of nanoshell suspension using circulating water. The percentage of cell apoptosis after irradiation by Ar and 532 nm lasers were 44.6 and 42.6 %, respectively. The obtained results suggest that controlling the NP-laser interaction using optical properties of nanoshells and the laser parameters can be used to develop a new cancer therapy modality via targeted nanoshell and drug delivery.

Advanced nanoparticle strategies for optimizing RNA therapeutic delivery in neurodegenerative disorders.

Neurodegenerative diseases affect many people worldwide, and as the population ages, the incidence of these conditions increases. Alzheimer's disease (AD) and Parkinson's disease (PD) are the most prevalent neurodegenerative disorders worldwide. Different medicines are being used to control symptoms related to these conditions, but no treatment has yet been approved. Both genetic and environmental factors are involved in disease pathogenesis, and research on the pathophysiological pathways is still ongoing. The role of subcellular pathways and dysregulation in RNA pathways has been highlighted in pathophysiological studies, and treatment strategies focused on these pathways can be a promising approach. Many experiments have been conducted on delivering RNA cargo to the CNS to modulate various pathways involved. Yet another challenge to be faced is the effective transport of desired molecules to targets, which can be greatly hindered by distinct barriers limiting transport to the CNS, most noticeably the blood-brain barrier (BBB). Nanotechnology and the use of different nano-carriers for the delivery of nucleotides, peptides, proteins, and drug molecules are currently of great interest as these carriers help with better delivery and protection and, as a result, improve the effectiveness of the cargo. Nanocarriers can protect susceptible RNA molecules from possible degradation or destruction and improve their ability to reach the brain by enhancing BBB penetration. Different mechanisms for this process have been hypothesized. This review will go through the therapeutic application of RNA molecules in the treatment of AD and PD and the role of nanocarriers in overcoming delivery challenges and enhancing efficacy.

Advancing Myocardial Infarction Treatment: Harnessing Multi-Layered Recellularized Cardiac Patches with Fetal Myocardial Scaffolds and Acellular Amniotic Membrane.

PURPOSE: Myocardial infarction (MI) is a leading cause of irreversible functional cardiac tissue loss, requiring novel regenerative strategies. This study assessed the potential therapeutic efficacy of recellularized cardiac patches, incorporating fetal myocardial scaffolds with rat fetal cardiomyocytes and acellular human amniotic membrane, in adult Wistar rat models of MI. METHODS: Decellularized myocardial tissue was obtained from 14 to 16 week-old human fetuses that had been aborted. Chemical detergents (0.1% EDTA and 0.2% sodium dodecyl sulfate) were used to prepare the fetal extracellular matrix (ECM), which was characterized for bio-scaffold microstructure and biocompatibility via scanning electron microscopy (SEM) and MTT assay, respectively. Neonatal cardiomyocytes were extracted from the ventricles of one-day-old Wistar rats' littermates and characterized through immunostaining against Connexin-43 and α-smooth muscle actin. The isolated cells were seeded onto decellularized tissues and covered with decellularized amniotic membrane. Sixteen healthy adult Wistar rats were systematically allocated to control and MI groups. MI was induced via arterial ligation. Fourteen days post-operation, the MI group was received the engineered patches. Following a two-week post-implantation period, the animals were euthanized, and the hearts were harvested for the graft evaluation. RESULTS: Histological analysis, DAPI staining, and ultra-structural examination corroborated the successful depletion of cellular elements, while maintaining the integrity of the fetal ECM and architecture. Subsequent histological and immunohistochemichal (IHC) evaluations confirmed effective cardiomyocyte seeding on the scaffolds. The application of these engineered patches in MI models resulted in increased angiogenesis, reduced fibrosis, and restricted scar tissue formation, with the implanted cardiomyocytes remaining viable at graft sites, indicating prospective in vivo cell viability. CONCLUSIONS: This study suggests that multi-layered recellularized cardiac patches are a promising surgical intervention for myocardial infarction, showcasing significant potential by promoting angiogenesis, mitigating fibrosis, and minimizing scar tissue formation in MI models. These features are pivotal for enhancing the therapeutic outcomes in MI patients, focusing on the restoration of the myocardial structure and function post-infarction.

Electrical stimulation enhances sciatic nerve regeneration using a silk-based conductive scaffold beyond traditional nerve guide conduits.

Despite recent advancements in peripheral nerve regeneration, the creation of nerve conduits with chemical and physical cues to enhance glial cell function and support axonal growth remains challenging. This study aimed to assess the impact of electrical stimulation (ES) using a conductive nerve conduit on sciatic nerve regeneration in a rat model with transection injury. The study involved the fabrication of conductive nerve conduits using silk fibroin and Au nanoparticles (AuNPs). Collagen hydrogel loaded with green fluorescent protein (GFP)-positive adipose-derived mesenchymal stem cells (ADSCs) served as the filling for the conduit. Both conductive and non-conductive conduits were applied with and without ES in rat models. Locomotor recovery was assessed using walking track analysis. Histological evaluations were performed using H&E, luxol fast blue staining and immunohistochemistry. Moreover, TEM analysis was conducted to distinguish various ultrastructural aspects of sciatic tissue. In the ES + conductive conduit group, higher S100 (p < 0.0001) and neurofilament (p < 0.001) expression was seen after 6 weeks. Ultrastructural evaluations showed that conductive scaffolds with ES minimized Wallerian degeneration. Furthermore, the conductive conduit with ES group demonstrated significantly increased myelin sheet thickness and decreased G. ratio compared to the autograft. Immunofluorescent images confirmed the presence of GFP-positive ADSCs by the 6th week. Locomotor recovery assessments revealed improved function in the conductive conduit with ES group compared to the control group and groups without ES. These results show that a Silk/AuNPs conduit filled with ADSC-seeded collagen hydrogel can function as a nerve conduit, aiding in the restoration of substantial gaps in the sciatic nerve with ES. Histological and locomotor evaluations indicated that ES had a greater impact on functional recovery compared to using a conductive conduit alone, although the use of conductive conduits did enhance the effects of ES.

Efficacy of hydrogels for repair of traumatic spinal cord injuries: A systematic review and meta-analysis.

Hydrogels have been used as promising biomaterials for regeneration and control of pathophysiological events after traumatic spinal cord injuries (TSCI). However, no systematic comparison was conducted to show the effect of hydrogels on pathophysiological events. This study was designed to address this issue and evaluate the regenerative potential of hydrogels after TSCI. From 2857 records found in MEDLINE and EMBASE databases (April 23, 2021), 49 articles were included based on our inclusion/exclusion criteria. All studies discussing the effect of hydrogels on at least one of the main pathophysiological events after TSCI, including inflammation, axon growth, remyelination, glial scar formation, cavity size, and locomotor functional recovery were included. For statistical analysis, we used mean difference with 95% confidence intervals for locomotor functional recovery. The results showed that both natural and synthetic hydrogels could reduce the inflammatory response, hinder glial scar formation, and promote axon growth and vascularization. Also, the meta-analysis of the BBB score showed that using the hydrogels can lead to locomotor functional recovery. It was found that hydrogels are more efficient when used in transection and hemisection injuries (SMD: 1.89; 95% CI: 1.26, 2.52; P < .00001) compared to other injury models. The pre-formed implanted hydrogels (SMD: 1.79; 95% CI: 1.24, 2.34; P < .00001) found to be more effective compared to injection (SMD: 1.58; 95% CI: 0.64, 2.52; P = 0.0009). In conclusion, based on the available evidence, it was concluded that hydrogel composition as well as implantation method are dominant factors affecting tissue regeneration after TSCI and should be chosen according to the injury model in animal studies.

Influence of reducing agents on in situ synthesis of gold nanoparticles and scaffold conductivity with emphasis on neural differentiation.

BACKGROUND: Recorded advancements in nerve tissue regeneration have still not provided satisfactory results, and complete physiological recovery is not assured. The engineering of nanofibrous scaffolds provides a suitable platform for stem cell transplantation by controlling cell proliferation and differentiation to replace lost cells. In this study, a conductive scaffold was fabricated by in situ synthesis of gold nanoparticles (Au-NPs) on electrospun polycaprolactone/chitosan nanofibrous scaffolds and its effect on neural differentiation of mesenchymal stem cells was investigated. METHOD: The conductive scaffold was prepared using polycaprolactone/chitosan solution containing soluble Au ions by electrospinning approach. In situ synthesis of Au-NPs was conducted using two reducing agents, Tetrakis(hydroxymethyl)phosphonium chloride (THPC) as an organophosphorus compound and formaldehyde, and also different reduction times. Morphology and distribution of the Au-NPs on the nanofibrous scaffolds were assessed using field emission scanning electron microscopy (FE-SEM) and energy dispersed X-ray spectroscopy (EDX). The hydrophilicity and biocompatibility of the scaffolds were determined by water contact angle and MTT assays respectively. The characterization of the scaffolds was proceeded by testing the porosity, tensile strength and electrical conductivity. Also, the scaffold's ability to support neural differentiation of mesenchymal stem cells was evaluated by immune-staining/blotting of Beta tubulin III. RESULTS & CONCLUSION: FE-SEM and EDX results demonstrated the uniform distribution of Au-NPs on electrospun nanofibers made of a combination of polycaprolactone and chitosan (PCL/CS). We found that electrical conductivity of the scaffolds fabricated using THPC for 4 days and formaldehyde for 7 days was in the range of electrical conductivity of the scaffolds suitable for nerve regeneration. Contact angle measurements showed the effect of Au-NPs on the hydrophilic properties of the scaffolds, where the scaffold showed the porosity of 50% in the presence of Au-NPs. Au-NPs decoration on the scaffold decreased the mechanical properties with the ultimate strength of 14 (MPa). In vitro assessment demonstrated the potential of the fabricated conductive scaffold to enhance the attachment and proliferation of fibroblast cells, and differentiation potential of mesenchymal stem cells toward neuron-like cells. This designed scaffold holds promise as a future carrier and delivery platform in nerve tissue engineering.

Kidney tissue engineering in preclinical models of renal failure: a systematic review and meta-analysis.

Aim: This study aims to compare the efficacy of tissue engineering for kidney reconstruction. Materials & methods: We searched MEDLINE, EMBASE (May 2021), and reference lists of review articles. Results: 19 articles matched our inclusion criteria. A range of natural, synthetic and hybrid scaffolds with or without incorporating cells/growth factors was investigated in 937 animals. More favorable results were observed with a combination of two or more biomaterials, addition of bioactive moieties, and cell seeding. Creatinine concentration, PAX2, collagen type-1, α-SMA, vimentin, IL-1, IL-6 and TNF-α gene expressions were significantly increased compared with native control. Conclusion: Tissue engineering can improve renal function and regeneration; however, further research could benefit from using hybrid scaffolds, stem cells and large animal models.

Organ transplantation is limited by donor organ shortage throughout the world. Tissue engineering involves the use of biocompatible scaffold upon which cells can grow into functional tissues. Researchers have already experimented with kidney tissue engineering on several animal models. In this research, we systematically looked for all available studies in literature to collate and contrast the results of such studies. We found 19 relevant articles involving 937 animals. We learned that, in general, the use of biomaterial combinations, addition of specific biomolecules, and seeding of cells on scaffolds were associated with more favorable results. Quantitative analysis of several markers supported these conclusions. Despite advances in the field, kidney tissue engineering is still at its infancy, and more controlled animal experiments on more novel biomaterial are needed before we could translate this technique to humans.

Evaluation and Comparison of the Effects of Mature Silkworm (Bombyx mori) and Silkworm Pupae Extracts on Schwann Cell Proliferation and Axon Growth: An In Vitro Study.

Background: Silkworm products were first used by physicians more than 8500 years ago, in the early Neolithic period. In Persian medicine, silkworm extract has several uses for treating and preventing neurological, cardiac, and liver diseases. Mature silkworms (Bombyx mori) and their pupae contain a variety of growth factors and proteins that can be used in many repair processes, including nerve regeneration. Objectives: The study aimed to evaluate the effects of mature silkworm (Bombyx mori), and silkworm pupae extract on Schwann cell proliferation and axon growth. Methods: Silkworm (Bombyx mori) and silkworm pupae extracts were prepared. Then, the concentration and type of amino acids and proteins in the extracts were evaluated by Bradford assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and liquid chromatograph-mass spectrometer (LC-MS/MS). Also, the regenerative potential of extracts for improving Schwann cell proliferation and axon growth was examined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay, electron microscopy, and NeuroFilament-200 (NF-200) immunostaining. Results: According to the results of the Bradford test, the total protein content of pupae extract was almost twice that of mature worm extract. Also, SDS-PAGE analysis revealed numerous proteins and growth factors, such as bombyrin and laminin, in extracts that are involved in the repair of the nervous system. In accordance with Bradford's results, the evaluation of extracts using LC-MS/MS revealed that the number of amino acids in pupae extract was higher than in mature silkworm extract. It was found that the proliferation of Schwann cells at a concentration of 0.25 mg/mL in both extracts was higher than the concentrations of 0.01 and 0.05 mg/mL. When using both extracts on dorsal root ganglion (DRGs), an increase in length and number was observed in axons. Conclusions: The findings of this study demonstrated that extracts obtained from silkworms, especially pupae, can play an effective role in Schwann cell proliferation and axonal growth, which can be strong evidence for nerve regeneration, and, consequently, repairing peripheral nerve damage.

microRNAs as novel diagnostic biomarkers in endometriosis patients: a systematic review and meta-analysis.

OBJECTIVE: To investigate whether miRNAs have a remarkable pooled diagnostic accuracy, sensitivity, and specificity as noninvasive biomarkers to distinguish endometriosis patients from non-endometriosis women. METHODS: A comprehensive literature search of PubMed, Embase, and ProQuest was performed through February 21, 2021 to find relevant studies. Two reviewers independently screened each article, and discrepancies were resolved by consensus. Deeks' funnel plot asymmetry test was performed to assess the publication bias of included studies. The STATA software and RevMan 5.4 were used for data analysis and quality assessment, respectively. RESULTS: The overall quality of the studies was moderate to high. In total 87 datasets were assessed miRNAs' performance which results in sensitivity: 0.82, specificity: 0.79, DOR: 18, NPV: 0.80, PPV: 0.78, PLR: 3.97, and NLR: 022. We conducted subgroup analyses, which showed panels of miRNAs (DOR: 54) and serum (DOR: 43) as a target tissue was more reliable to utilize as biomarkers. Deeks' funnel plot showed that there is no publication bias (P-value = 0.25). CONCLUSIONS: Panels of miRNAs differentiate endometriosis patients from non-endometriosis women with high sensitivity and specificity; therefore, it has the potential to use as a noninvasive biomarker.

Biomedical applications of silkworm (Bombyx Mori) proteins in regenerative medicine (a narrative review).

Silk worm (Bombyx Mori) protein, have been considered as potential materials for a variety of advanced engineering and biomedical applications for decades. Recently, silkworm silk has gained significant importance in research attention mainly because of its remarkable and exceptional mechanical properties. Silk has already been shown to have unique interactions with cells in tissues through bio-recognition units. The natural silk contains fibroin and sericin and has been used in various tissues of the human body (skin, bone, nerve, and so on). Besides, silk also still has anti-cancer, anti-tyrosinase, anti-coagulant, anti-oxidant, anti-bacterial, and anti-diabetic properties. This article is supposed to describe the diverse biomedical capabilities of B. Mori silk as the appropriate biomaterial among the assorted natural and artificial polymers that are presently accessible, and ideal for usage in regenerative medicine fields.

Decellularized human amniotic membrane reinforced by MoS2-Polycaprolactone nanofibers, a novel conductive scaffold for cardiac tissue engineering.

In order to regenerate myocardial tissues with functional characteristics, we need to copy some properties of the myocardium, such as its extracellular matrix and electrical conductivity. In this study, we synthesized nanosheets of Molybdenum disulfide (MoS2), and integrated them into polycaprolactone (PCL) and electrospun on the surface of decellularized human amniotic membrane (DHAM) with the purpose of improving the scaffolds mechanical properties and electrical conductivity. For in vitro studies, we seeded the mouse embryonic cardiac cells, mouse Embryonic Cardiac Cells (mECCs), on the scaffolds and then studied the MoS2 nanocomposites by scanning electron microscopy and Raman spectroscopy. In addition, we characterized the DHAM/PCL and DHAM/PCL-MoS2 by SEM, transmission electron microscopy, water contact angle measurement, electrical conductivity, and tensile test. Besides, we confirmed the scaffolds are biocompatible by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT assay. Furthermore, by means of SEM images, it was shown that mECCs attached to the DHAM/PCL-MoS2 scaffold have more cell aggregations and elongated morphology. Furthermore, through the Real-Time PCR and immunostaining studies, we found out cardiac genes were maturated and upregulated, and they also included GATA-4, c-TnT, NKX 2.5, and alpha-myosin heavy chain in cells cultured on DHAM/PCL-MoS2 scaffold in comparison to DHAM/PCL and DHAM. Therefore, in terms of cardiac tissue engineering, DHAM nanofibrous scaffolds reinforced by PCL-MoS2 can be suggested as a proper candidate.

Fabrication and in vitro evaluation of 3D composite scaffold based on collagen/hyaluronic acid sponge and electrospun polycaprolactone nanofibers for peripheral nerve regeneration.

Replacement of peripheral nerve autografts with tissue engineered nerve grafts will potentially resolve the lack of nerve tissue especially in patients with severe concomitant soft tissue injuries. This study attempted to fabricate a tissue engineered nerve graft composed of electrospun PCL conduit filled with collagen-hyaluronic acid (COL-HA) sponge with different COL-HA weight ratios including 100:0, 98:2, 95:5 and 90:10. The effect of HA addition on the sponge porosity, mechanical properties, water absorption and degradation rate was assessed. A good cohesion between the electrospun PCL nanofibers and COL-HA sponges were seen in all sponges with different HA contents. Mechanical properties of PCL nanofibrous layer were similar to the rat sciatic nerve; the ultimate tensile strength was 2.23 ± 0.35 MPa at the elongation of 35%. Additionally, Schwann cell proliferation and morphology on three dimensional (3D) composite scaffold were evaluated by using MTT and SEM assays, respectively. Rising the HA content resulted in higher water absorption as well as greater pore size and porosity, while a decrease in Schwann cell proliferation compared to pure collagen sponge, although reduction in cell proliferation was not statistically significant. The lower Schwann cell proliferation on the COL-HA was attributed to the greater degradation rate and pore size of the COL-HA sponges. Also, dorsal root ganglion assay showed that the engineered 3D construct significantly increases axon growth. Taken together, these results suggest that the fabricated 3D composite scaffold provide a permissive environment for Schwann cells proliferation and maturation and can encourage axon growth.

Improving motor neuron-like cell differentiation of hEnSCs by the combination of epothilone B loaded PCL microspheres in optimized 3D collagen hydrogel.

Spinal cord regeneration is limited due to various obstacles and complex pathophysiological events after injury. Combination therapy is one approach that recently garnered attention for spinal cord injury (SCI) recovery. A composite of three-dimensional (3D) collagen hydrogel containing epothilone B (EpoB)-loaded polycaprolactone (PCL) microspheres (2.5 ng/mg, 10 ng/mg, and 40 ng/mg EpoB/PCL) were fabricated and optimized to improve motor neuron (MN) differentiation efficacy of human endometrial stem cells (hEnSCs). The microspheres were characterized using liquid chromatography-mass/mass spectrometry (LC-mas/mas) to assess the drug release and scanning electron microscope (SEM) for morphological assessment. hEnSCs were isolated, then characterized by flow cytometry, and seeded on the optimized 3D composite. Based on cell morphology and proliferation, cross-linked collagen hydrogels with and without 2.5 ng/mg EpoB loaded PCL microspheres were selected as the optimized formulations to compare the effect of EpoB release on MN differentiation. After differentiation, the expression of MN markers was estimated by real-time PCR and immunofluorescence (IF). The collagen hydrogel containing the EpoB group had the highest HB9 and ISL-1 expression and the longest neurite elongation. Providing a 3D permissive environment with EpoB, significantly improves MN-like cell differentiation and maturation of hEnSCs and is a promising approach to replace lost neurons after SCI.

Ficus Carica L. Latex: Possible Chemo-Preventive, Apoptotic Activity and Safety Assessment.

Hepatocellular carcinoma is the third cause of cancer-related mortality with the low 5-year survival in which more than 50 percent of patients have recurrent cancer within 2 years of treatment. The present study investigated the cytotoxicity and lethal dose of Ficus carica L. (Figure) latex and phytochemical composition of effective fraction. Figure latex was collected in summer and 4 fractions of Figure latex were prepared. The cytotoxic effect of each fraction was studied and the most effective fraction was selected for apoptosis assay, acute toxicity study, and phytochemical analysis using column chromatography. The isolated compounds were identified by 1H-NMR, 13C-NMR, and mass spectroscopy. Chloroform fraction was the most effective fraction with the IC50 value of 0.219 and 0.748 mg/mL for HepG2 and NIH cell lines, respectively. Presence of cells in early apoptotic phase was documented by flow cytometry assay. Single dose administration of 2g/kg of fraction did not cause any death. Phytochemical analyses confirmed presence of lupeol acetate and lupeol palmitate in chloroform fraction. The present study revealed that the chloroform fraction is not only 3.4 times more toxic in HepG2 cell line but also has low in-vivo toxicity which could be considered as a good candidate for a chemo-preventive agent.

Time-dependent microglia and macrophages response after traumatic spinal cord injury in rat: a systematic review.

OBJECTIVE: To acquire evidence-based knowledge in temporal and spatial patterns of microglia/macrophages changes to facilitate finding proper intervention time for functional restoration after traumatic spinal cord injury (TSCI). SETTING: Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. METHODS: We searched PubMed and EMBASE via Ovid SP with no temporal and linguistic restrictions. Besides, hand-search was performed in the bibliographies of relevant studies. The experimental non-interventional and non-transgenic animal studies confined to the rat species which assess the pathological change of microglia /macrophages at the specified time were included. RESULTS: We found 15,315 non-duplicate studies. Screening through title and abstract narrowed down to 607 relevant articles, 31 of them were selected based on the inclusion criteria. The reactivity of the microglia/macrophages initiates in early hours PI in contusion, compression and transection models. Cells activity reached a maximum within 48 h to 28 days in compression, 7 days in contusion and between 4 and 60 days in transection models. Inflammatory response occurred at the epicenter, in or near the lesion site in both gray and white matter in all three injury models with a maximum extension of one centimeter caudal and rostral to the epicenter in the gray matter in contusion and transection models. CONCLUSION: This study was designed to study spatial-temporal changes in the activation of microglia/macrophages overtime after TSCI. We were able to demonstrate time-dependent cell morphological changes after TSCI. The peak times of cell reactivity and the areas where the cells responded to the injury were determined.

Biofunctionalized peptide-based hydrogel as an injectable scaffold for BDNF delivery can improve regeneration after spinal cord injury.

BACKGROUND: The complex pathophysiological events occurring after traumatic spinal cord injuries (TSCI) make this devastating trauma still incurable. Peptide amphiphile (PA) hydrogels are nanobiomaterials displaying desirable properties for application in regenerative medicine because they are absorbable, injectable, allowing biofunctionalization, controlling release of trophic factors and mimic extracellular matrix (ECM). In this study, we explored the potentiality of the IKVAV-functionalized PA hydrogel to provide a permissive environment for cell migration and growth as well as sustained release of BDNF at the lesion after severe compression injury model. METHODS: The IKVAV-functionalized PA was synthesized by automated solid-phase approach and its secondary structure was evaluated by Circular dichroism (CD) spectroscopy. The potential of IKVAV-functionalized PA to self-assemble into nanofibers and hydrogel formation were assessed using transmission electron microscopy (TEM). Release profiles of BDNF from hydrogel and the bioactivity of the released BDNF from hydrogel were determined using ELISA and DRG bioassay, respectively. Severe spinal cord injury was induced using clip compression at T7-T8 vertebral segment. Twenty four hours post-injury the animals were treated by either IKVAV PA hydrogel, BDNF-loaded IKVAV PA hydrogel, BDNF solution or saline. Two and six weeks later, animals were sacrificed and the lesion site was evaluated based on GFAP, CD68 and ß III tubulin immunoreactivity. Also, locomotor recovery was assessed during 6 weeks using Basso, Beattie, Bresnahan (BBB) scoring test. RESULTS: The IKVAV PA arranged into nanofibrous structure and provided a sustained release of BDNF over 21 days while preserved the bioactivity of BDNF. Also, BDNF loading influenced the hydrogel nanostructure resulting in aligned orientation of nanofibers. Injection of BDNF-loaded IKVAV PA hydrogel resulted in a considerable axon preservation and astrogliosis reduction at 6 weeks post-injury without showing any inflammatory reaction. However, the BBB score was not statistically different between different treatment groups. CONCLUSION: Although the locomotor functional recovery was not observed in this study, the axon preservation and minimal inflammation in animals treated with BDNF-incorporated hydrogel indicate the potentiality of the designed intervention for further evaluations in the path of developing efficient therapies for severe spinal cord injury.