Dynamic adaptation of mesenchymal stem cell physiology upon exposure to surface micropatterns

Human mesenchymal stem (hMSCs) are defined as multi-potent colony-forming cells expressing a specific subset of plasma membrane markers when grown on flat tissue culture polystyrene. However, as soon as hMSCs are used for transplantation, they are exposed to a 3D environment, which can strongly impact cell physiology and influence proliferation, differentiation and metabolism. Strategies to control in vivo hMSC behavior, for instance in stem cell transplantation or cancer treatment, are skewed by the un-physiological flatness of the standard well plates. Even though it is common knowledge that cells behave differently in vitro compared to in vivo, only little is known about the underlying adaptation processes. Here, we used micrometer-scale defined surface topographies as a model to describe the phenotype of hMSCs during this adaptation to their new environment. We used well established techniques to compare hMSCs cultured on flat and topographically enhanced polystyreneand observed dramatically changed cell morphologies accompanied by shrinkage of cytoplasm and nucleus, a decreased overall cellular metabolism, and slower cell cycle progression resulting in a lower proliferation rate in cells exposed to surface topographies. We hypothesized that this reduction in proliferation rate effects their sensitivity to certain cancer drugs, which was confirmed by higher survival rate of hMSCs cultured on topographies exposed to paclitaxel. Thus, micro-topographies can be used as a model system to mimic the natural cell micro-environment, and be a powerful tool to optimize cell treatment in vitro

Calorie restriction-induced changes in the secretome of human adipocytes, comparison with resveratrol-induced secretome effects

Obesity is characterized by dysfunctional white adipose tissue (WAT) that ultimately may lead to metabolic diseases. Calorie restriction (CR) reduces the risk for age and obesity-associated complications. The impact of CR on obesity has been examined with human intervention studies, which showed alterations in circulating adipokines. However, a direct effect of CR on the human adipocyte secretome remains elusive. Therefore, the effect of a 96h low glucose CR on the secretion profile of in vitro cultured mature human SGBS adipocytes was investigated by using proteomics technology. Low-glucose CR decreased the adipocyte triglyceride contents and resulted in an altered secretion profile. Changes in the secretome indicated an improved inflammatory phenotype. In addition, several adipocyte-secreted proteins related to insulin resistance showed a reversed expression after low-glucose CR. Furthermore, 6 novel CR-regulated adipocyte-secreted proteins were identified. Since resveratrol (RSV) mimics CR we compared results from this study with data from our previous RSV study on the SGBS adipocyte secretome. The CR and RSV adipocyte secretomes partly differed from each other, although both treatment strategies lead to secretome changes indicating a less inflammatory phenotype. Furthermore, both treatments induced SIRT1 expression and resulted in a reversed expression of detrimental adipokines associated with metabolic complications

Clonal deletion of self-reactive T cells in irradiation bone marrow chimeras and neonatally tolerant mice. Evidence for intercellular transfer of Mlsa

Tolerance to Mlsa has been shown to be associated with clonal deletion of cells carrying TCR beta chain variable regions V beta 6 or V beta 8.1 in mice possessing I-E antigens. To evaluate the rules of tolerance induction to Mlsa we prepared irradiation bone marrow chimeras expressing Mlsa or Mlsb and I-E by different cell types. Deletion of V beta 6+, Mlsa-reactive T cells required the presence of Mlsa and I-E products either on bone marrow-derived cells or on irradiated recipient cells. Tolerance was induced when Mlsa and I-E were expressed by distinct cells of the chimera. Also neonatally tolerized mice exhibited depletion of V beta 6+ cells after injection of I-E- Mlsa spleen cells (DBA/1) into newborn I-E+ Mlsb mice (BALB/c x B10.G)F1. These results suggest that the product of the Mlsa locus is soluble and/or may be transferred from cell to cell and bound to I-E antigens. The chimera experiments also showed that tolerance to Mlsa is H-2 allele independent, i.e., is apparently unrestricted. Differentiation of chimeric (H-2d/Mlsa x H-2q/Mlsb)F1 stem cells in either an H-2d or an H-2q thymus revealed that tolerance assessed by absence of V beta 6+ T cells is not dependent on the thymically determined restriction specificity of T cells

Major adverse cardiovascular events in older emergency department patients presenting with non-cardiac medical complaints

OBJECTIVE: The risk of major adverse cardiovascular events (MACE) for older emergency department (ED) patients presenting with non-cardiac medical complaints is unknown. To apply preventive measures timely, early identification of high-risk patients is incredibly important. We aimed at investigating the incidence of MACE within one year after their ED visit and the predictive value of high-sensitivity cardiac troponin T (hs-cTnT) and N‑terminal pro-B-type natriuretic peptide (NT-proBNP) for subsequent MACE. METHODS: This is a substudy of a Dutch prospective cohort study (RISE UP study) in older (≥ 65 years) medical ED patients who presented with non-cardiac complaints. Biomarkers were measured upon ED arrival. Cox-regression analysis was used to determine the predictive value of the biomarkers, when corrected for other possible predictors of MACE, and area under the curves (AUCs) were calculated. RESULTS: Of 431 patients with a median age of 79 years, 86 (20.0%) developed MACE within 1 year. Both hs-cTnT and NT-proBNP were predictive of MACE with an AUC of 0.74 (95% CI 0.68-0.80) for both, and a hazard ratio (HR) of 2.00 (95% CI 1.68-2.39) and 1.82 (95% CI 1.57-2.11) respectively. Multivariate analysis correcting for other possible predictors of MACE revealed NT-proBNP as an independent predictor of MACE. CONCLUSION: Older medical ED patients are at high risk of subsequent MACE within 1 year after their ED visit. While both hs-cTnT and NT-proBNP are predictive, only NT-proBNP is an independent predictor of MACE. It is likely that early identification of those at risk offers a window of opportunity for prevention

Diet-induced weight loss decreases adipose tissue oxygen tension with parallel changes in adipose tissue phenotype and insulin sensitivity in overweight humans

Background/objectives: Although adipose tissue (AT) hypoxia is present in rodent models of obesity, evidence for this in humans is limited. Here, we investigated the effects of diet-induced weight loss (WL) on abdominal subcutaneous AT oxygen tension (pO 2), AT blood flow (ATBF), AT capillary density, AT morphology and transcriptome, systemic inflammatory markers and insulin sensitivity in humans. Subjects/methods: Fifteen overweight and obese individuals underwent a dietary intervention (DI), consisting of a 5-week very-low-calorie diet (VLCD, 500 kcal day -1; WL), and a subsequent 4-week weight stable diet (WS). Body composition, AT pO 2 (optochemical monitoring), ATBF (133 Xe washout), and whole-body insulin sensitivity were determined, and AT biopsies were collected at baseline, end of WL (week 5) and end of WS (week 9). Result: Body weight, body fat percentage and adipocyte size decreased significantly during the DI period. The DI markedly decreased AT pO 2 and improved insulin sensitivity, but did not alter ATBF. Finally, the DI increased AT gene expression of pathways related to mitochondrial biogenesis and non-mitochondrial oxygen consumption. Conclusions: VLCD-induced WL markedly decreases abdominal subcutaneous AT pO 2, which is paralleled by a reduction in adipocyte size, increased AT gene expression of mitochondrial biogenesis markers and non-mitochondrial oxygen consumption pathways, and improved whole-body insulin sensitivity in humans.</p