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Mesenchymal stem cells (MSCs) have a therapeutic potential in tissue repair because of capacity for multipotent differentiation and their ability to modulate the immune response. In this study, we examined the ability of human placental MSCs (pMSCs) to modify the differentiation of human monocytes into macrophages and assessed the influence of pMSCs on important macrophage functions. We used GM-CSF to stimulate the differentiation of monocytes into the M1 macrophage pathway and then co-cultured these cells with pMSCs in the early stages of macrophage differentiation. We then evaluated the effect on differentiation by microscopic examination and by quantification of molecules important in the differentiation and immune functions of macrophages using flow cytometry and ELISA. The mechanism by which pMSCs could mediate their effects on macrophage differentiation was also studied. The co-culture of pMSCs with monocytes stimulated to follow the inflammatory M1 macrophage differentiation pathway resulted in a shift to anti-inflammatory M2-like macrophage differentiation. This transition was characterized by morphological of changes typical of M2 macrophages, and by changes in cell surface marker expression including CD14, CD36, CD163, CD204, CD206, B7-H4 and CD11b, which are distinctive of M2 macrophages. Co-culture with pMSCs reduced the expression of the costimulatory molecules (CD40, CD80 and CD86) and increased the expression of co-inhibitory molecules (CD273, CD274 and B7-H4) as well as the surface expression of major histocompatibility complex (MHC-II) molecules. Furthermore, the secretion of IL-10 was increased while the secretion of IL-1β, IL-12 (p70) and MIP-1α was decreased; a profile typical of M2 macrophages. Finally, pMSCs induced the phagocytic activity and the phagocytosis of apoptotic cells associated with M2- like macrophages; again a profile typical of M2 macrophages. We found that the immunoregulatory effect of pMSCs on macrophage differentiation was mediated by soluble molecules acting partially via glucocorticoid and progesterone receptors. We have shown that pMSCs can transition macrophages from an inflammatory M1 into an anti-inflammatory M2 phenotype. Our findings suggest a new immunosuppressive property of pMSCs that may be employed in the resolution of inflammation associated with inflammatory diseases and in tissue repair.

Background Bone marrow derived mesenchymal stem cells (BM-MSCs) are used extensively in transplantation but their use is associated with many problems including low abundance in BM, low overall number, decreased differentiation potential with age and the invasive isolation procedures needed to obtain BM. We report a novel method of isolating placental MSCs (pMSCs) from chorionic villi, which exhibit the phenotypic and functional characteristics that will make them an attractive source of MSCs for cell-based therapy. Methods A novel explant approach was used to isolate pMSCs from chorionic villi of human placentae. These pMSCs were characterized by flow cytometry and were differentiated into adipocytes, osteocytes and chondrocytes using differentiation medium as demonstrated by cytochemical staining. The gene and protein expression profiles of pMSCs were also characterized using real time polymerase chain reaction (PCR) and flow cytometry, respectively. In addition, cytokine secretion by pMSCs was also analysed using sandwich enzyme-linked immunosorbent assay (ELISA) technique. Moreover, the migration and proliferation potentials of pMSCs were also determined. Results pMSCs were isolated from fetal part of the chorionic villi and these pMSCs expressed CD44, CD90, CD105, CD146, CD166 and HLA-ABC but not CD14, CD19, CD40, CD45, CD80, CD83, CD86 and HLA-DR. In addition, these pMSCs differentiated into osteocytes, chondrocytes and adipocytes and they also expressed several adhesion molecules, chemokines/receptors, growth factor receptors and cytokines/receptors. Moreover, they secreted many cytokines (IL-1Ra, IL6, IL8, IL10, IL11 and IL15) and they were able to proliferate. Furthermore, they migrated in response to chemotactic factors including stromal cell-derived factor-1 (SDF-1), platelet derived growth factor (PDGF), hepatocyte growth factor (HGF), and monocyte chemotactic protein-1 (MCP-1). Conclusions We devised a novel explant method of isolating pMSCs that expressed many biological factors responsible for mediating cellular processes such as migration/homing, immune modulation and angiogenesis. Therefore, we suggest that pMSCs prepared from human term placental chorionic villous explants are an attractive source of MSCs for cell therapy.

Mesenchymal stem cell (MSC) therapies for the treatment of diseases associated with inflammation and oxidative stress employ primarily bone marrow MSCs (BMMSCs) and other MSC types such as MSC from the chorionic villi of human term placentae (pMSCs). These MSCs are not derived from microenvironments associated with inflammation and oxidative stress, unlike MSCs from the decidua basalis of the human term placenta (DBMSCs). DBMSCs were isolated and then extensively characterized. Differentiation of DBMSCs into three mesenchymal lineages (adipocytes, osteocytes, and chondrocytes) was performed. Real-time polymerase chain reaction (PCR) and flow cytometry techniques were also used to characterize the gene and protein expression profiles of DBMSCs, respectively. In addition, sandwich enzyme-linked immunosorbent assay (ELISA) was performed to detect proteins secreted by DBMSCs. Finally, the migration and proliferation abilities of DBMSCs were also determined. DBMSCs were positive for MSC markers and HLA-ABC. DBMSCs were negative for hematopoietic and endothelial markers, costimulatory molecules, and HLA-DR. Functionally, DBMSCs differentiated into three mesenchymal lineages, proliferated, and migrated in response to a number of stimuli. Most importantly, these cells express and secrete a distinct combination of cytokines, growth factors, and immune molecules that reflect their unique microenvironment. Therefore, DBMSCs could be attractive, alternative candidates for MSC-based therapies that treat diseases associated with inflammation and oxidative stress.

Mesenchymal stem cells derived from the chorionic villi of human term placenta (pMSCs) have drawn considerable interest because of their multipotent differentiation potential and their immunomodulatory capacity. These properties are the foundation for their clinical application in the fields of stem cell transplantation and regenerative medicine. Previously, we showed that pMSCs induce an anti-inflammatory phenotype in human macrophages. In this study, we determined whether pMSCs modify the differentiation and maturation of human monocytes into dendritic cells (DCs). The consequences on dendritic function and on T cell proliferation were also investigated. Interleukin-4 (IL-4) and granulocyte-macrophage colony stimulating factor (GM-CSF) were used to stimulate the differentiation of monocytes into immature dendritic cells (iDCs), which were subsequently co-cultured with pMSCs. Lipopolysaccharide (LPS) was used to induce maturation of iDCs into mature dendritic cells (mDCs). Flow cytometry and enzyme-linked immunosorbent assays (ELISA) were used to quantify the effect pMSC co-culturing on DC differentiation using CD1a, a distinctive marker of DCs, as well as other molecules important in the immune functions of DCs. The phagocytic activity of iDCs co-cultured with pMSCs, and the effects of iDCs and mDC stimulation on T cell proliferation, were also investigated. Monocyte differentiation into iDCs was inhibited when co-cultured with pMSCs and maturation of iDCs by LPS treatment was also prevented in the presence of pMSCs as demonstrated by reduced expression of CD1a and CD83, respectively. The inhibitory effect of pMSCs on iDC differentiation was dose dependent. In addition, pMSC co-culture with iDCs and mDCs resulted in both phenotypic and functional changes as shown by reduced expression of costimulatory molecules (CD40, CD80, CD83 and CD86) and reduced capacity to stimulate CD4(+) T cell proliferation. In addition, pMSC co-culture increased the surface expression of major histocompatibility complex (MHC-II) molecules on iDCs but decreased MHC-II expression on mDCs. Moreover, pMSC co-culture with iDCs or mDCs increased the expression of immunosuppressive molecules [B7H3, B7H4, CD273, CD274 and indoleamine-pyrrole 2,3-dioxygenase (IDO). Additionally, the secretion of IL-12 and IL-23 by iDCs and mDCs co-cultured with pMSCs was decreased. Furthermore, pMSC co-culture with mDCs decreased the secretion of IL-12 and INF-γ whilst increasing the secretion of IL-10 in a T cell proliferation experiment. Finally, pMSC co-culture with iDCs induced the phagocytic activity of iDCs. We have shown that pMSCs have an inhibitory effect on the differentiation, maturation and function of DCs, as well as on the proliferation of T cells, suggesting that pMSCs can control the immune responses at multiple levels.

Background Mesenchymal stem cells derived from the chorionic villi of human placentae (pMSCs) produce a unique array of mediators that regulate the essential cellular functions of their target cells. These properties make pMSCs attractive candidates for cell-based therapy. Here, we examined the effects of culturing human natural killer (NK) cells with pMSCs on NK cell functions. Methods pMSCs were cultured with IL-2-activated and non-activated NK cells. NK cell proliferation and cytolytic activities were monitored. NK cell expression of receptors mediating their cytolytic activity against pMSCs, and the mechanisms underlying this effect on pMSCs, were also investigated. Results Our findings show that IL-2-activated NK cells, but not freshly isolated NK cells, efficiently lyse pMSCs and that this response might involve the activating NK cell receptor CD69. Interestingly, although pMSCs expressed HLA class I molecules, they were nevertheless lysed by NK cells, suggesting that HLA class I antigens do not play a significant role in protecting pMSCs from NK cell cytolytic activity. Co-culturing NK cells with pMSCs also inhibited NK cell expression of receptors, including CD69, NKpG2D, CD94, and NKp30, although these co-cultured NK cells were not inhibited in lysing cancer cells in vitro. Importantly, co-cultured NK cells significantly increased their production of molecules with anti-tumor effects. Conclusions These findings suggest that pMSCs might have potential applications in cancer therapy.

Two accredited cotton (Gossypium hirsutum L.) cultivars (Aleppo 118 and Deir Al-Zour 22) have been investigated to assess physiological, morphological, and molecular responses under water shortage conditions. Both cultivars have shown early flowering. However, higher percentage of treated ‘Aleppo 118’ plants kept flowering towards the end of the growing season compared to treated ‘Deir Al-Zour 22’ plants. Both cultivars kept consistent micronaire and cohesion under normal and water shortage conditions. The cultivar Aleppo 118 displayed more consistent fiber quality between control and treated plants, while ‘Deir Al-Zour 22’ showed variation in fiber length and strength between control and treated plants. Results have demonstrated an increase in fold expression of DREB1A, TPS and HSPCB genes in the flowering stage of treated plants compared to the controls. Results also showed a continuous activation of DREB1A gene in the two critical growing stages of a cotton life cycle, flowering and boll development in treated plants of ‘Deir Al-Zour 22’. This work illustrates the different responses of two cotton cultivars under water shortage stress and its impact on flowering and fiber traits.

Type 1 diabetes mellitus (T1DM) is an increasingly encountered chronic illness in Saudi Arabia. It is known to have an immune-mediated pathogenesis, which results in the loss of insulin-secreting β-cells responsible for maintaining normal blood glucose levels. The three main autoantibodies identified to play a role in the pathogenesis are islet cell antibodies (ICA), insulin autoantibodies (IAA) and glutamic acid decarboxylase antibodies (GAD). This study aims to determine at what age during childhood the autoantibodies ICA, IAA and GAD are most prevalent, and identify any correlation between their presence and the severity of the initial clinical presentation. Medical records of children diagnosed with T1DM in Riyadh in 2000-2007 were reviewed, and a total of 98 patients were included in the study (age range: 1-12 years, mean: 6.6 years, equal numbers by gender), of which 49% presented with diabetic ketoacidosis (DKA). Results showed that 67% were positive for ICA, 36% for IAA and 84.4% for GAD. The presence of ICA was predominant in children aged under six years. The presence of ICA and GAD in the absence of IAA was associated with more severe clinical presentation.

Background. In the last decade, cord blood (CB) has proven to be a valuable source of hematopoietic stem cells for transplantation to treat many hematological disorders. Since then, many CB banks have been established worldwide. Our aim was to estimate the level of public awareness of CB banking in Saudi Arabia. Study Design and Methods. A self-administered questionnaire of 22 multiple choices was conveniently distributed, consisting of demographics, awareness measure, attitude toward banking preference, and donation for research data. Results. A total of 1146 participants have completed the questionnaire. The majority were young female 19–25 years old (26%), who are college graduates (57%) with middle class socioeconomic status (82%). The subjective assessment of the overall knowledge was inadequate (66%). For the objective assessment, 12 questions were asked about CB source, collection, storage, and usage. Only half of the subjects (52%) knew that CB is a source of stem cells. More than half did not know the main use of CB. About half did not know about the method of collection nor the condition of storing. Conclusion. This study shows a high lack of knowledge about CB banking. More than half of the subjects were unaware of CB banking and its uses. However, most subjects are accepting CB storage, which anticipates great impact and efficacy on educational programs. Moreover, the data demonstrated that health professionals were not the source of knowledge. We recommend having comprehensive educational campaigns with clear information about CB banking to facilitate positive perspectives towards donation and scientific research.

The objective of this study was to evaluate leptin, ghrelin, and leptin/ghrelin ratio in critically ill patients and association of leptin/ghrelin ratio with outcomes. This is a sub-study of the PermiT trial (ISRCTN68144998). A subset of 72 patients who were expected to stay >14 days in the Intensive care unit were enrolled. Blood samples were collected on days 1, 3, 5, 7, and 14. Samples were analyzed for leptin and active ghrelin in addition to other hormones. Baseline leptin/ghrelin ratio was calculated, and patients were stratified into low and high leptin/ghrelin ratio based on the median value of 236. There was a considerable variation in baseline leptin level: Median 5.22 ng/mL (Q1, Q3: 1.26, 17.60). Ghrelin level was generally low: 10.61 pg/mL (Q1, Q3: 8.62, 25.36). Patients with high leptin/ghrelin ratio compared to patients with low leptin/ghrelin ratio were older, had higher body mass index and more likely to be diabetic. There were no differences in leptin/ghrelin ratio between patients who received permissive underfeeding and standard feeding. Multivariable logistic regression analysis showed that age and body mass index were significant independent predictors of high leptin–ghrelin ratio. Leptin–ghrelin ratio was not associated with 90-day mortality or other outcomes. Age and body mass index are predictors of high leptin/ghrelin ratio. Leptin/ghrelin ratio is not affected by permissive underfeeding and is not associated with mortality.

The effect of short-term caloric restriction on gene expression in critically ill patients has not been studied. In this sub-study of the PermiT trial (Permissive Underfeeding or Standard Enteral Feeding in Critically Ill Adults Trial- ISRCTN68144998), we examined gene expression patterns in peripheral white blood cells (buffy coat) associated with moderate caloric restriction (permissive underfeeding) in critically ill patients compared to standard feeding. Blood samples collected on study day 1 and 14 were subjected to total RNA extraction and gene expression using microarray analysis. We enrolled 50 patients, 25 in each group. Among 1751 tested genes, 332 genes in 12 pathways were found to be significantly upregulated or downregulated between study day 1 and 14 (global p value for the pathway ≤ 0.05). Using the heatmap, the differential expression of genes from day 1 to 14 in the permissive underfeeding group was compared to the standard feeding group. We further compared gene expression signal intensity in permissive underfeeding compared standard feeding by constructing univariate and multivariate linear regression models on individual patient data. We found differential expression of several genes with permissive underfeeding, most notably those related to metabolism, autophagy and other cellular functions, indicating that moderate differences in caloric intake trigger different cellular pathways.