Hydrogel-Based Skin Regeneration.

The skin is subject to damage from the surrounding environment. The repair of skin wounds can be very challenging due to several factors such as severe injuries, concomitant infections, or comorbidities such as diabetes. Different drugs and wound dressings have been used to treat skin wounds. Tissue engineering, a novel therapeutic approach, revolutionized the treatment and regeneration of challenging tissue damage. This field includes the use of synthetic and natural biomaterials that support the growth of tissues or organs outside the body. Accordingly, the demand for polymer-based therapeutic strategies for skin tissue defects is significantly increasing. Among the various 3D scaffolds used in tissue engineering, hydrogel scaffolds have gained special significance due to their unique properties such as natural mimicry of the extracellular matrix (ECM), moisture retention, porosity, biocompatibility, biodegradability, and biocompatibility properties. First, this article delineates the process of wound healing and conventional methods of treating wounds. It then presents an examination of the structure and manufacturing methods of hydrogels, followed by an analysis of their crucial characteristics in healing skin wounds and the most recent advancements in using hydrogel dressings for this purpose. Finally, it discusses the potential future advancements in hydrogel materials within the realm of wound healing.

Biomarker based biosensors: An opportunity for diagnosis of COVID-19.

Early diagnosis and treatment of diseases are crucial research areas of human health. For early diagnosis, one method that has proven efficient is the detection of biomarkers which can provide real-time and accurate biological information. Most biomarker detection is currently carried out at localised dedicated laboratories using large and automated analysers, increasing waiting time and costs. Smaller, faster, and cheaper devices could potentially replace these time-consuming laboratory analyses and make analytical results available as point-of-care diagnostics. Innovative biosensor-based strategies could allow biomarkers to be tested reliably in a decentralised setting. Early diagnosis of COVID-19 patients has a key role in order to use quarantine and treatment strategies in a timely manner. Raised levels of several biomarkers in COVID-19 patients are associated with respiratory infections or dysfunction of various organs. Through clinical studies of COVID-19 patient biomarkers such as ferritin, Interleukins, albumin and …are found to reveals significant differences in their excretion ranges from healthy patients and patients with SARS-CoV-2, in addition to the development of biomarkers based biosensor such as stated biomarkers can be used and to investigate more specific biomarkers further proteomic analysis can be performed. This review presents several biomarker alterations in COVID-19 patients such as salivary, circulatory, coagulation, cardiovascular, renal, liver, C-reactive protein (CRP), immunological and inflammatory biomarkers. Also, biomarker sensors based on electrochemical, optical, and lateral flow characteristics which have potential applications for SARS-COV-2 in the recent COVID-19 pandemic, will be discussed.

Current Advances in Wound Healing and Regenerative Medicine.

Treating chronic wounds is a common and costly challenge worldwide. More advanced treatments are needed to improve wound healing and prevent severe complications such as infection and amputation. Like other medical fields, there have been advances in new technologies promoting wound healing potential. Regenerative medicine as a new method has aroused hope in treating chronic wounds. The technology improving wound healing includes using customizable matrices based on synthetic and natural polymers, different types of autologous and allogeneic cells at different differentiation phases, small molecules, peptides, and proteins as a growth factor, RNA interference, and gene therapy. In the last decade, various types of wound dressings have been designed. Emerging dressings include a variety of interactive/ bioactive dressings and tissue-engineering skin options. However, there is still no suitable and effective dressing to treat all chronic wounds. This article reviews different wounds and common treatments, advanced technologies and wound dressings, the advanced wound care market, and some interactive/bioactive wound dressings in the market.

Articular Cartilage Injury; Current Status and Future Direction.

Today, treatments of cartilage and osteochondral lesions are routine clinical procedures. The avascular and hard-to-self-repair nature of cartilage tissue has posed a clinical challenge for the replacement and reconstruction of damaged cartilage. Treatment of large articular cartilage defects is technically difficult and complex, often accompanied by failure. Articular cartilage cannot repair itself after injury due to a lack of blood vessels, lymph, and nerves. Various treatments for cartilage regeneration have shown encouraging results, but unfortunately, none have been the perfect solution. New minimally invasive and effective techniques are being developed. The development of tissue engineering technology has created hope for articular cartilage reconstruction. This technology mainly supplies stem cells with various sources of pluripotent and mesenchymal stem cells. This article describes the treatments in detail, including types, grades of cartilage lesions, and immune mechanisms in cartilage injuries.

Erythropoietin improves spatial learning and memory in streptozotocin model of dementia.

Alzheimer's disease is associated to impairments of learning and memory. Because studies demonstrated that erythropoietin has positive effects on central nervous system, the aim of this study was to evaluate the effect of erythropoietin on spatial learning and memory in a well defined model for Alzheimer's disease. Rat model of Alzheimer's was created by injecting streptozotocin in lateral ventricles of the brain. Two weeks later, the rats were assessed through passive avoidance learning test to confirm the induction of Alzheimer's. After that, they received erythropoietin (5000IU/kg) every other day, for two weeks and then spatial learning and memory were assessed by a 5-day protocol of Morris water maze test in them. The results showed that streptozotocin severely damaged learning and memory in rats. Erythropoietin had no significant effect in the control rats; however, it significantly improved learning and memory in rats with Alzheimer's disease, as the task performance of the rats treated with erythropoietin was like the control group. The results suggest that erythropoietin can be considered as an effective treatment for neurodegenerative damages.

Challenges in osteoarthritis treatment.

Osteoarthritis (OA) is the most common form of arthritis and a degenerative joint cartilage disease that is the most common cause of disability in the world among the elderly. It leads to social, psychological, and economic costs with financial consequences. The principles of OA treatment are to reduce pain and stiffness as well as maintain function. In recent years, due to a better understanding of the underlying pathophysiology of OA, a number of potential therapeutic advances have been made, which include tissue engineering, immune system manipulation, surgical technique, pharmacological, and non-pharmacological treatments. Despite this, there is still no certain cure for OA, and different OA treatments are usually considered in relation to the stage of the disease. The purpose of the present review is to summarize and discuss the latest results of new treatments for OA and potential targets for future research.

The Potential of Mesenchymal Stem/Stromal Cell Therapy in Mustard Keratopathy: Discovering New Roads to Combat Cellular Senescence.

Mesenchymal stem/stromal cells (MSCs) are considered a valuable option to treat ocular surface disorders such as mustard keratopathy (MK). MK often leads to vision impairment due to corneal opacification and neovascularization and cellular senescence seems to have a role in its pathophysiology. Herein, we utilized intrastromal MSC injections to treat MK. Thirty-two mice were divided into four groups based on the exposure to 20 mM or 40 mM concentrations of mustard and receiving the treatment or not. Mice were clinically and histopathologically examined. Histopathological evaluations were completed after the euthanasia of mice after four months and included hematoxylin and eosin (H&E), CK12, and beta-galactosidase (ß-gal) staining. The treatment group demonstrated reduced opacity compared to the control group. While corneal neovascularization did not display significant variations between the groups, the control group did register higher numerical values. Histopathologically, reduced CK12 staining was detected in the control group. Additionally, ß-gal staining areas were notably lower in the treatment group. Although the treated groups showed lower severity of fibrosis compared to the control groups, statistical difference was not significant. In conclusion, it seems that delivery of MSCs in MK has exhibited promising therapeutic results, notably in reducing corneal opacity. Furthermore, the significant reduction in the ß-galactosidase staining area may point towards the promising anti-senescence potential of MSCs.

Adipose tissue-derived mesenchymal stem cells for breast tissue regeneration.

With an escalating incidence of breast cancer cases all over the world and the deleterious psychological impact that mastectomy has on patients along with several limitations of the currently applied modalities, it's plausible to seek unconventional approaches to encounter such a burgeoning issue. Breast tissue engineering may allow that chance via providing more personalized solutions which are able to regenerate, mimicking natural tissues also facing the witnessed limitations. This review is dedicated to explore the utilization of adipose tissue-derived mesenchymal stem cells for breast tissue regeneration among postmastectomy cases focusing on biomaterials and cellular aspects in terms of harvesting, isolation, differentiation and new tissue formation as well as scaffolds types, properties, material-host interaction and an in vitro breast tissue modeling.

Human Olfactory Mucosa Stem Cells Delivery Using a Collagen Hydrogel: As a Potential Candidate for Bone Tissue Engineering.

For bone tissue engineering, stem cell-based therapy has become a promising option. Recently, cell transplantation supported by polymeric carriers has been increasingly evaluated. Herein, we encapsulated human olfactory ectomesenchymal stem cells (OE-MSC) in the collagen hydrogel system, and their osteogenic potential was assessed in vitro and in vivo conditions. Collagen type I was composed of four different concentrations of (4 mg/mL, 5 mg/mL, 6 mg/mL, 7 mg/mL). SDS-Page, FTIR, rheologic test, resazurin assay, live/dead assay, and SEM were used to characterize collagen hydrogels. OE-MSCs encapsulated in the optimum concentration of collagen hydrogel and transplanted in rat calvarial defects. The tissue samples were harvested after 4- and 8-weeks post-transplantation and assessed by optical imaging, micro CT, and H&E staining methods. The highest porosity and biocompatibility were confirmed in all scaffolds. The collagen hydrogel with 7 mg/mL concentration was presented as optimal mechanical properties close to the naïve bone. Furthermore, the same concentration illustrated high osteogenic differentiation confirmed by real-time PCR and alizarin red S methods. Bone healing has significantly occurred in defects treated with OE-MSCs encapsulated hydrogels in vivo. As a result, OE-MSCs with suitable carriers could be used as an appropriate cell source to address clinical bone complications.

Fabrication of chitosan-polyvinyl alcohol and silk electrospun fiber seeded with differentiated keratinocyte for skin tissue regeneration in animal wound model.

Hybrid fibrous mat containing cell interactive molecules offers the ability to deliver the cells and drugs in wound bed, which will help to achieve a high therapeutic treatment. In this study, a co-electrospun hybrid of polyvinyl alcohol (PVA), chitosan (Ch) and silk fibrous mat was developed and their wound healing potential by localizing bone marrow mesenchymal stem cells (MSCs)-derived keratinocytes on it was evaluated in vitro and in vivo. It was expected that fabricated hybrid construct could promote wound healing due to its structure, physical, biological specifications. The fabricated fibrous mats were characterized for their structural, mechanical and biochemical properties. The shape uniformity and pore size of fibers showed smooth and homogenous structures of them. Fourier transform infrared spectroscopy (FTIR) verified all typical absorption characteristics of Ch-PVA + Silk polymers as well as Ch-PVA or pure PVA substrates. The contact angle and wettability measurement of fibers showed that mats found moderate hydrophilicity by addition of Ch and silk substrates compared with PVA alone. The mechanical features of Ch-PVA + Silk fibrous mat increase significantly through co-electrospun process as well as hybridization of these synthetic and natural polymers. Higher degrees of cellular attachment and proliferation obtained on Ch-PVA + Silk fibers compared with PVA and Ch-PVA fibers. In terms of the capability of Ch-PVA + Silk fibers and MSC-derived keratinocytes, histological analysis and skin regeneration results showed this novel fibrous construct could be suggested as a skin substitute in the repair of injured skin and regenerative medicine applications.

Design and characterization of biodegradable multi layered electrospun nanofibers for corneal tissue engineering applications.

Tissue engineering is one of the most promising areas for treatment of various ophthalmic diseases particularly for patients who suffer from limbal stem cell deficiency and this is due to the lack of existence of appropriate matrix for stem cell regeneration. The aim of this research project is to design and fabricate triple layered electrospun nanofibers as a suitable corneal tissue engineering scaffold and the objective is to investigate and perform various in vitro tests to find the most optimum and suitable scaffold for this purpose. Electrospun scaffolds were prepared in three layers. Poly(d, l-lactide-co-glycolide; PLGA, 50:50) nanofibers were electrospun as outer and inner layers of the scaffold and aligned type I collagen nanofibers were electrospun in the middle layer. Furthermore, the scaffolds were cross-linked by 1-ethyl-3-(3 dimethylaminopropyl) carbodiimide hydrochloride and glutaraldehyde. Structural, physical, and mechanical properties of scaffolds were investigated by using N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, contact angle measurement, tensile test, degradation, shrinkage analysis, and scanning electron microscopy (SEM). In addition, capability to support cell attachment and viability were characterized by SEM, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, and 4',6-diamidino-2-phenylindole staining. According to the result of Brunauer-Emmett-Teller analysis, specific surface area of electrospun scaffold was about 23.7 m2 g-1 . Tensile tests on cross-linked scaffolds represented more suitable hydrophilicity and tensile behavior. In addition, degradation rate analysis indicated that noncross-linked scaffolds degraded faster than cross-linked one and cross-linking led to controlled shrinkage in the scaffold. The SEM analysis depicted nano-sized fibers in good shape. Also, the in vitro study represented an improved cell attachment and proliferation in the presence of human endometrial stem cells for both cross-linked and noncross-linked samples. The current study suggests the possibility of producing an appropriate substrate for successful cornea tissue engineering with a novel design.