فاکتور رشد

The field of tissue engineering utilizes interdisciplinary sciences such as to repair or regenerate damaged tissues through the integration of cellular biology, biomaterials, pharmaceuticals, and signaling molecules to repair and reconstruct damaged tissues. Scaffolds, by mimicking the natural extracellular matrix (ECM), play a vital role in guiding cellular activities. Cartilage, as a tissue without blood vessels and nerves, lacks the ability for self-repair, and its injuries are always considered a clinical challenge that affects the lives of millions of people and incurs significant treatment costs. In recent years, the electrospinning technique has gained attention for the production of nanofibers. Electrospun scaffolds, mimicking the extracellular matrix of cartilage, provide a suitable environment for the attachment, proliferation, and differentiation of chondrocytes. The use of nanofibrous scaffolds, along with cells and signaling molecules compatible with the target tissue, is of particular importance for cartilage tissue regeneration. Various natural and synthetic polymers have been used for cartilage tissue regeneration via electrospinning, and their effects on nanofiber morphology have been extensively studied.

This review emphasized recent advancements in the preparation of electrospun scaffolds for cartilage tissue engineering and discussed methods to improve their performance. It also provides an overview of natural, synthetic, and composite biomaterials utilized for electrospinning cartilage scaffolds. The function of nanofibers in delivering signaling molecules for cartilage regeneration is explored. Current challenges in this field are addressed, along with strategies to overcome them, offering potential improvements in cartilage repair techniques and their future clinical application.

Endurance training has been shown to reduce growth hormone levels more effectively than resistance training in obese children and adolescents. However, the effects of endurance training on non-obese children and adolescents remain unclear. This study aims to determine the effects of endurance training on growth factor and insulin-like growth factor-1 (IGF-1) in children and adolescents after abdominal surgeries through a systematic review and meta-analysis.

This study is a systematic review and meta-analysis based on the PRISMA statement. Articles published up to early 2022 were searched in databases including PubMed, Web of Science, EBSCO, CINAHL, MEDLINE, SPORT Discus, Scopus, Mag Iran, and SID. The search strategy used Boolean operators with keywords: (youth or children or adolescents or teenagers or boys or girls or minors) and (hormone or growth hormone or insulin-like growth factor-1 or endocrine glands or cytokine) and (exercise or training) and (endurance or resistance) and (laparotomy or abdominal surgery).

A total of nine studies (190 participants) were included in this review, and it was found that endurance exercises have beneficial effects. The meta-analysis results showed that endurance training did not significantly increase growth hormone levels at the end of the study compared to the beginning (mean difference: 48 ng/ml - CI 95%: 0.02-0.99, P = 0.06-2%). Similarly, endurance training did not result in a significant change in IGF-1 levels at the end of the study compared to the beginning (mean difference: 22 ng/ml - CI 95%: 12.2-92.47, I2=0%, P = 0.92).

In children and adolescents, hormonal systems adapt to long-term training, resulting in various effects. Endurance exercises have no impact on growth hormone and insulin-like growth factor 1 (IGF-1) in children and adolescents after abdominal surgeries.

Diabetes is a metabolic disease with high blood sugar levels. Olfactory ensheathing cells (OECs) are able to express various growth factors and integrin-linked kinase (ILK) plays an important role in regulating various processes of cells. In this study, we investigated the effects of silybinin on the expression of vascular-endothelial growth factor (VEGF) and ILK under normal and high glucose conditions in OECs.

In this study, OECs were extracted from the olfactory mucosa of neonatal rats and cultured. Low (1,5M) and high (50,75 µM) concentrations of silybinin were added to the cell culture media under normal and high glucose conditions. At the end of the study, we measured the expression of VEGF and ILK proteins using western blot technique. Data were analyzed by ANOVA test.

Under high glucose conditions, low concentrations of silybinin maintained expression and at high concentrations silybinin caused a dose-dependent decrease in ILK significantly. However, under high glucose conditions, low concentrations of silybinin significantly decreased expression of VEGF but high concentrations of silybinin caused a significant dose- dependent increase in VEGF expression.

High glucose condition increased ILK and VEGF expression in the OECs, and treatment with lower concentrations of silybinin maintained ILK expression and decreased VEGF expression. Therefore, it seems that lower concentrations of silybinin can be effective in protecting cells from cytotoxicity due to diabetes hyperglycemia by stabilizing ILK and reducing VEGF levels.

Platelet Gel (PG) is rich in growth factors including Platelet-Derived Growth Factor (PDGF), Transforming Growth Factor (TGF-β), Vascular Endothelial Growth Factor (VEGF), Epidermal Growth Factor (EGF), and Fibroblast Growth Factor (FGF) that have healing properties. In this study, the platelet growth factors were evaluated in the platelet gel prepared from umbilical cord blood (CB) and peripheral blood.

In this case-control study, blood samples from 30 umbilical cord blood volunteers and 30 peripheral blood donors were evaluated. PG was prepared from the collected samples. The concentrations of platelet growth factors in platelet gel supernatant were measured at different storage times (0, 0.5, 1, 6, and 24 hours) using the enzyme-linked immunosorbent assay technique.

ELISA assay revealed that the concentration of PDGF and VEGF in CB-PG supernatant was dramatically higher following. 6 hours of incubation of PG (p< 0.01). The concentration levels of PDGF in CB-PG at 0 and 6 hours of incubation were 38.9 ± 7.1 and 73.2 ± 10.9 ng/mL, respectively. Also TGF and EGF levels were significantly increased following 24 hours of incubation (p< 0.01). At all times tested, the level of measured growth factors in CB-PG was higher than the peripheral blood PG.

Conclusions  :

A variety of growth factors is released from the platelets at significant levels in CB-PG which can mediate healing process.

The ultimate goal in periodontal treatment is to achieve a functional and anatomical regeneration of lost tissues. Due to the promising outcomes of biologic modifiers in regenerative therapies, this systematic review aimed at evaluating the effects of various biologic modifiers used in intra-bony osseous defects in animal models.

Electronic databases were searched for articles published in March 2010-March 2020 that had evaluated the effect of bio-modifiers used in periodontal intra-bony osseous defects in animal models. Screening was performed based on inclusion/exclusion criteria and SYRCLE tool was used for studies’ quality assessment.

After screening the titles, abstracts, and full-texts, 18 studies were included in qualitative analysis and five studies entered the meta-analysis. According to the configuration of osseous defects, the studies were categorized into three subgroups. Based on histological findings, all these biologic markers significantly enhanced new bone and cementum formation compared to control groups (P<0.001). The meta-analysis showed that biologic modifiers could significantly increase bone regeneration
(1.58 mm, 95% CI: 1.12-2.03, P˂0.001) and cementum regeneration (1.27 mm, 95% CI: 0.84-1.70, P˂0.001) in one-wall osseous defects.

Biologic modifiers namely growth factors could positively affect periodontal regeneration, particularly the cementum and bone in animal models. Further human studies are necessary to address the clinical use of these biomaterials.

Acute and chronic wound healing has always been problematic. Stem cells with or without the scaffold carrying these cells have been proposed as new methods in the treatment of wounds. In this case study we have tried to examine the effect of scaffold made of polyether sulfone (PES) alone, with stem cells and along with stem cell and growth factor on wound healing in rats.
This experimental study was conducted in Animal Laboratory of Hazrat Fatemeh Hospital in 2012. In this study, 48 rats were randomly divided into four groups. A wound created on the back of each rat at the size of 3×3 cm. The surface of the wound in the first group is covered with PES seeded with adipose-derived stem cell (ASC) and growth factor (GF), in the second group with polyether Sulfone seeded with ASC, in the third group only with PEWS, and in the fourth group (control) with Vaseline gauze. On 20th and 35th days, the surface of the wound was assessed by photography in order to understand the process of healing. In addition, on days 20 and 45, the histopathology characteristics of the samples were studied with a biopsy of the wounds.
The Results of wound healing in the control group was better than the other groups and its statistical difference between others was meaningful. (P=0.008, P=0.013, P=0.001) On day 20, by examining histopathological characteristics including epithelialization, the number of inflammatory cells, the amount of angiogenesis and collagen synthesis in control group, we gained better results. (P=0.000), But on day 45, the results in different parameters were not equal.
polyether sulfone scaffold alone or with adipose-derived stem cells couldn’t improve the process of wound healing. Also adding vascular endothelial growth factor (VEGF) did not change the results significantly.

Controlling the release of drugs and other therapeutic molecules has great importance in novel drug delivery. Nanoparticulate systems have the ability to control drug release and increase the presence of these compounds in blood flow and could convey them to a specific position. Growth factors are endogenous peptide which begins cellular signals to regulate cellular activities. The main problem is the instability of these factors in bloodstream and lack of proper distribution in systemic administration. Nanoparticles mainly nanocarriers have the ability to overcome this problem and play a great role in intelligentization of tissue engineering because of their unique features, including the creation of physical protection and collaboration with the scaffolds and cells. Due to the increasing use of growth factors in healing damaged tissues, and their application in tissue engineering, in this article a number of nanoparticles useful for the release of growth factors with a few examples are reviewed.

Peripheral nerve injuries which can lead to a physical disability. If the defect is very low، direct suture without tension on both ends of the cut nerve regeneration is considered as a standard procedure. Otherwise، to reconstruct the axons، the gap must be filled by graft material in order to the guidance. Due to the similarity of the matrix tubular skeletal muscle and nerve muscles graft was used to repair in this study. In the present experimental study، 42 female Wistar rats were divided into three groups and underwent surgery. In the first group a narrow strip of muscle was prepared by freezing – thawing، and later sutured between the distal and proximal sciatic nerve. In the second group، the gap caused by muscle graft was regenerated and the nerve growth factor and laminin was injected into the graft. In the control group، the two ends of the cut nerve were hidden beneath the adjacent muscles. Next، a group of rats with sciatic functional index was investigated for the behavioral. On the other group were examined for histological studies after two months. Sciatic functional index and Mean counts of myelinated fibers in two graft groups compared with the control group was significant) p<0. 05). Statistical analysis was performed using ANOVA test. co-axially aligned muscle grafts were an appropriate alternative substitute for repairing. It seems that the nerve growth factor and laminin have a positive role in axonal regeneration and functional recovery acceleration.

Primary culture takes place following the cell isolation from tissues. Isolation and culture of melanocytes based on their roll in the protection of body against hazardous sun rays، production of skin، cornea and hair color is really important. This study was done to set isolation، culture and proliferation of melanocytes from children foreskin and adult eyelashes، and also comparison of two types of melanocyte culture medium.

Human foreskin and eyelash samples were used for melanocyte isolation and culture. After isolation of epidermis from dermis، epidermis cell suspensions were prepared by enzymatic digestion. The isolated cells were cultured in two melanocyte selective culture media. Immunocytochemistary and reverse transcription-polymerase chain reaction (RT-PCR) assays were used for confirmation of isolated and cultured melanocytes.

Our results indicated that isolated melanocyte cultured in the selective medium without phorbol esters is better than the melanocytes cultured in selective medium cont-aining phorbol esters not only morphologically but also physiologically and from the aspect of cell adhesion. In addition، the results showed that isolated melanocyte from adult eyelashes are more dendritic than melanocytes isolated from children foreskin. Conversely، our results indicated that the number of cell passages in melanocyte isolat-ed from foreskin is more than melanocytes isolated from adult eyelashes.

Melanocytes cultured in selective medium containing convenient growth factors in absence of phorbol esters show more native physiological and adhesive properties. In addition، melanocyte isolated from younger tissues such as foreskin have better proliferative and sub-culturing properties so we suggest isolation and culture of younger tissues.

Tissue engineering is knowledge of designing tissues such as maxillofacial bone. Three key factors of tissue enginee-ring comprise of morphogenesis factors، responding stem cells and scaffolds. Growth factors have an important role in differentiation and cell morphogenesis. In this review، literature was searched for bone engineering in craniomaxillofacial tissues and the use of growth factors was reviewed. Reviewing MEDLINE indexed articles shows various growth factors applied in jaw bone regeneration. Application of growth factors should be standardized in order to improve their use in future bone tissue engineering.

Insulin-like growth factor 1 has an important role in cell proliferation and growth. Polymorphism in IGF-1 gene changes the level of this hormone and increases the risk of colorectal cancer. The aim of this study is to assess the incidence of IGF-1 polymorphism rs5742612 in Iranian population and to investigate the influence of this polymorphism in increasing the risk of colorectal cancer. Genotyping of IGF-1 gene was performed in a series of 110 colorectal cancer patients and 110 controls by using polymerase chain reaction and restriction fragment length polymorphism genotyping (PCR-RFLP) assays. We calculated odds ratio and confidence interval (CI) of IGF-1 genotypes to determine if these polymorphisms are associated with colorectal cancer. No significant association was found between polymorphism of IGF-1 gene (rs5742612) and increased risk of colorectal cancer (p=0.92). The odds ratio for the heterozygous genotype CT versus the normal genotype CC was 1.3 (95% CI: 0.3-6.27) and the odds ratio for the mutant genotype TT versus the normal genotype CC was 0.0. The frequency of the mutant allele was 2.5%. These findings suggest that IGF-1 rs5742612 polymorphism is not associated with increased risk of colorectal cancer. (Quarterly Journal of Sabzevar University of Medical Sciences, Volume 19, Number 2, pp.109-115).

The aim of this study is to improve development outcome of vitrified mouse embryos by adding of fibroblast growth factor (FGF) and Hepatocyte growth factor (HGF) into medium culture. Two-cell mouse embryos were obtained from oviduct and then vitrified by cryotop. After warming the embryos, they were cultured in T6 medium supplemented with dose of 20 ng/ml of each FGF and HGF. Embryo developmental rate was compared between vitrified, non vitrified and control groups. Embryos development rate was assessed. The results showed that cleavage and development rate of vitrified and non-vitrified mouse embryos increased significantly in the culture medium supplemented with growth factors as compared to the control group (p<0.01). Also, there is significant difference in morula developmental rates between vitrified and non-vitrified embryos treated with growth factors (p<0.05), but this difference has not been observed in blastocyst formation rate (p>0.05). The results of this study demonstrate that enriching the culture medium with growth factors improves preimplantation developmental rates of mouse embryos after vitrification