VEGF gene expression in adult human thymus fat: a correlative study with hypoxic induced factor and cyclooxygenase-2

Radiation Resistance: A Matter of Transcription Factors

Currently, radiation therapy is one of the standard therapies for cancer treatment. Since the first applications, the field of radiotherapy has constantly improved, both in imaging technologies and from a dose-painting point of view. Despite this, the mechanisms of resistance are still a great problem to overcome. Therefore, a more detailed understanding of these molecular mechanisms will allow researchers to develop new therapeutic strategies to eradicate cancer effectively. This review focuses on different transcription factors activated in response to radiotherapy and, unfortunately, involved in cancer cells’ survival. In particular, ionizing radiations trigger the activation of the immune modulators STAT3 and NF-κB, which contribute to the development of radiation resistance through the up-regulation of anti-apoptotic genes, the promotion of proliferation, the alteration of the cell cycle, and the induction of genes responsible for the Epithelial to Mesenchymal Transition (EMT). Moreover, the ROS-dependent damaging effects of radiation therapy are hampered by the induction of antioxidant enzymes by NF-κB, NRF2, and HIF-1. This protective process results in a reduced effectiveness of the treatment, whose mechanism of action relies mainly on the generation of free oxygen radicals. Furthermore, the previously mentioned transcription factors are also involved in the maintenance of stemness in Cancer Stem Cells (CSCs), a subset of tumor cells that are intrinsically resistant to anti-cancer therapies. Therefore, combining standard treatments with new therapeutic strategies targeted against these transcription factors may be a promising opportunity to avoid resistance and thus tumor relapse.

Differences in the neovascular potential of thymus versus subcutaneous adipose-derived stem cells from patients with myocardial ischaemia

Adipose tissue-derived multipotent mesenchymal cells (ASCs) participate in the information of blood vessels under hypoxic conditions. It is probable that the susceptibility of ASCs to the influence of age and ageing-associated pathologies compromises their therapeutic effectiveness depending on the adipose tissue depot. Our aim was to examine the neovascular potential under hypoxic conditions of ASCs-derived from thymic (thymASCs) and subcutaneous (subASCs) adipose tissue from 39 subjects with and without type 2 diabetes mellitus (T2DM) and of different ages who were undergoing coronary bypass surgery. We confirmed a significant decrease in the percentage of CD34⁺ CD31^- CD45^- subASCs in the cell yield of subASCs and in the survival of cultured endothelial cells in the medium conditioned by the hypox-subASCs with increasing patient age, which was not observed in thymASCs. Whereas the length of the tubules generated by hypox-subASCs tended to correlate negatively with patient age, tubule formation capacity of the hypoxic thymASCs increased significantly. Compared with subASCs, thymASCs from subjects over age 65 and without T2DM showed higher cell yield, tubule formation capacity, vascular endothelial growth factor secretion levels, and ability to promote endothelial cell survival in their conditioned medium. Deterioration in subASCs neovascular potential relative to thymASCs derived from these subjects was accompanied by higher expression levels of NOX4 mRNA and fibrotic proteins. Our results indicate that thymASCs from patients over age 65 and without T2DM have a higher angiogenic potential than those from the other patient groups, suggesting they may be a good candidate for angiogenic therapy in subjects undergoing coronary bypass surgery.

Exposure of Persian sturgeon (Acipenser persicus) to cadmium results in biochemical, histological and transcriptional alterations

Sturgeon is one of the endangered families of fish in the Caspian Sea region, where there is up to 80% of their global caching. Unfortunately, in recent years, increase of pollutants has been resulted in their total population reduction. Due to their benthic nature, sturgeons are at great risk of exposing to contaminants such as cadmium. Despite their endangered status in the Caspian Sea, there are only a few studies on characterizing the relative sensitivity of sturgeons to cadmium. Adverse effects associated with pollution on angiogenesis are mediated by hypoxia inducing factor-1 (HIF-1) and vascular endothelial growth factor (VEGF). In this investigation, gene expression of two distinct HIFs-1, HIF-1α and HIF-2α, and VEGF was investigated at the mRNA transcript levels after exposure of Persian sturgeon (Acipenser persicus) to cadmium. VEGF, HIF-1α and HIF-2α expressions in treated Persian sturgeon were greater than controls. Significant increases (P<0.05) were also observed in cortisol and glucose levels compared to the control group especially in the fish exposed to higher cadmium concentration (800 μg/L). Plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactic acid dehydrogenase (LDH) levels were increased in the cadmium-exposed fish, although the observed increases were not significant between the control and 200 μg/L cadmium treatment at some sampling time points. Gill tissues also showed histopathological changes in the cadmium treatments. Overall, results indicated that cadmium resulted in some alterations in biochemical parameters, mRNA transcript level expression of two important angiogenesis related genes as well as histological alterations in Persian sturgeon.

Myocardial Ischemic Subject's Thymus Fat: A Novel Source of Multipotent Stromal Cells

Objective

Adipose Tissue Stromal Cells (ASCs) have important clinical applications in the regenerative medicine, cell replacement and gene therapies. Subcutaneous Adipose Tissue (SAT) is the most common source of these cells. The adult human thymus degenerates into adipose tissue (TAT). However, it has never been studied before as a source of stem cells.

Material and Methods

We performed a comparative characterization of TAT-ASCs and SAT-ASCs from myocardial ischemic subjects (n = 32) according to the age of the subjects.

Results

TAT-ASCs and SAT-ASCs showed similar features regarding their adherence, morphology and in their capacity to form CFU-F. Moreover, they have the capacity to differentiate into osteocyte and adipocyte lineages; and they present a surface marker profile corresponding with stem cells derived from AT; CD73⁺CD90⁺CD105⁺CD14^-CD19^-CD45^-HLA-DR. Interestingly, and in opposition to SAT-ASCs, TAT-ASCs have CD14⁺CD34⁺CD133⁺CD45^- cells. Moreover, TAT-ASCs from elderly subjects showed higher adipogenic and osteogenic capacities compared to middle aged subjects, indicating that, rather than impairing; aging seems to increase adipogenic and osteogenic capacities of TAT-ASCs.

Conclusions

This study describes the human TAT as a source of mesenchymal stem cells, which may have an enormous potential for regenerative medicine.

Thymus and aging: morphological, radiological, and functional overview

Aging is a continuous process that induces many alterations in the cytoarchitecture of different organs and systems both in humans and animals. Moreover, it is associated with increased susceptibility to infectious, autoimmune, and neoplastic processes. The thymus is a primary lymphoid organ responsible for the production of immunocompetent T cells and, with aging, it atrophies and declines in functions. Universality of thymic involution in all species possessing thymus, including human, indicates it as a long-standing evolutionary event. Although it is accepted that many factors contribute to age-associated thymic involution, little is known about the mechanisms involved in the process. The exact time point of the initiation is not well defined. To address the issue, we report the exact age of thymus throughout the review so that readers can have a nicely pictured synoptic view of the process. Focusing our attention on the different stages of the development of the thymus gland (natal, postnatal, adult, and old), we describe chronologically the morphological changes of the gland. We report that the thymic morphology and cell types are evolutionarily preserved in several vertebrate species. This finding is important in understanding the similar problems caused by senescence and other diseases. Another point that we considered very important is to indicate the assessment of the thymus through radiological images to highlight its variability in shape, size, and anatomical conformation.

Angiogenesis and vascular functions in modulation of obesity, adipose metabolism, and insulin sensitivity

White and brown adipose tissues are hypervascularized and the adipose vasculature displays phenotypic and functional plasticity to coordinate with metabolic demands of adipocytes. Blood vessels not only supply nutrients and oxygen to nourish adipocytes, they also serve as a cellular reservoir to provide adipose precursor and stem cells that control adipose tissue mass and function. Multiple signaling molecules modulate the complex interplay between the vascular system and the adipocytes. Understanding fundamental mechanisms by which angiogenesis and vasculatures modulate adipocyte functions may provide new therapeutic options for treatment of obesity and metabolic disorders by targeting the adipose vasculature.

Thymus fat as an attractive source of angiogenic factors in elderly subjects with myocardial ischemia

Aging negatively affects angiogenesis which is found to be linked to declined vascular endothelial growth factor (VEGF) production. Adult human thymus degenerates into fat tissue (thymus adipose tissue (TAT)). Recently, we described that TAT from cardiomyopathy ischemic subjects has angiogenic properties. The goal of our study was to analyze whether aging could also impair angiogenic properties in TAT as in other adipose tissue such as subcutaneous (subcutaneous adipose tissue (SAT)). SAT and TAT specimens were obtained from 35 patients undergoing cardiac surgery, making these tissues readily available as a prime source of adipose tissue. Patients were separated into two age-dependent groups; middle-aged (n = 18) and elderly (n = 17). Angiogenic, endothelial, and adipogenic expression markers were analyzed in both tissues from each group and correlations were examined between these parameters and also with age. There were no significant differences in subjects from either group in clinical or biological variables. Angiogenic markers VEGF-A, B, C, and D and adipogenic parameters, peroxisome proliferator-activated receptors (PPARγ2), FABP4, and ADRP showed elevated expression levels in TAT from elderly patients compared to the middle-aged group, while in SAT, expression levels of these isoforms were significantly decreased in elderly patients. VEGF-R1, VEGF-R2, VEGF-R3, Thy1, CD31, CD29, and VLA1 showed increased levels in TAT from the elderly compared to the middle-aged, while in SAT these levels displayed a decline with aging. Also, in TAT, angiogenic and endothelial parameters exhibited strong positive correlations with age. TAT appears to be the most appropriate source of angiogenic and endothelial factors in elderly cardiomyopathy subjects compared to SAT.

Proteomic analysis of the aqueous humor in patients with wet age-related macular degeneration

PURPOSE

A number of studies have shown that the levels of some proteins in the aqueous humor (AH) are altered and correlate with the mechanisms or prognosis of many eye diseases. To identify the possible mechanisms that lead to the development of wet age-related macular degeneration (AMD), a proteomic analysis of the AH composition from wet AMD patients was performed and compared with that from non-AMD cataract patients.

EXPERIMENTAL DESIGN

Six wet AMD and six non-AMD cataract patients were enrolled. A proteomic approach which included two-dimensional electrophoresis coupled with MS and bioinformatics methods were used to identify AH proteins with altered expression in wet AMD compared with non-AMD patients. An ELISA was used to validate the proteomic results.

RESULTS

We separated 78 protein spots and identified 68 that were differently expressed in the wet AMD group and controls. Numerous proteins identified in this study are implicated in inflammation, apoptosis, angiogenesis, and oxidative stress.

CONCLUSIONS AND CLINICAL RELEVANCE

The AH protein composition was significantly different between wet AMD and non-AMD patients. The proteins identified in this study may be potential biomarkers of wet AMD development and might play a role in the mechanisms of wet AMD.

The effects of cadmium on VEGF-mediated angiogenesis in HUVECs

Cadmium (Cd) is a highly toxic element that causes morphologic alterations and dysfunction in blood vessels. The altered vascular function caused by cadmium has been implicated in a range of chronic diseases, including hypertension. The effects of cadmium are a multisystem phenomenon involving inflammation, hypertrophy, apoptosis, angiogenesis and important processes involved in vascular remodeling systems. Vascular endothelial growth factor (VEGF) plays a major role in cell growth and angiogenesis under pathologic conditions. VEGF secretion is related to anti-apoptosis protein expression and attenuates apoptosis in endothelial cells. This study examined the VEGF-dependent mechanisms of angiogenesis and apoptosis in cadmium-treated endothelial cells (HUVECs). The effects and mechanisms of cadmium in endothelial cells (HUVECs) were examined by exposing the cells to different doses of cadmium chloride (2.5-40 μ m). After the cadmium treatment, the angiogenesis and apoptosis mechanisms related to VEGF in cadmium-treated HUVECs were examined. As a result, the low concentration of cadmium increased the tube formation in HUVECs. In addition, cadmium at concentrations of 5 and 10 μ m increased VEGF secretion and VEGFR2 activity, which suggest that cadmium affects the growth of blood vessels. All three MAPK pathways, namely ERK, JNK and p38, were activated by cadmium in HUVECs. However, high concentrations of cadmium caused cell damage, disrupted tube formation and inhibited VEGF expression and the activities of VEGFR2 and MAPK in HUVECs. Cadmium has dual functions through VEGF-dependent mechanisms in a dose-dependent manner. In this study, the dual effects of cadmium might alter angiogenesis and induce apoptosis through VEGF pathways in HUVECs.