Research Containing: Weightlessness Simulation

Modeled microgravity disrupts collagen I/integrin signaling during osteoblastic differentiation of human mesenchymal stem cells

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Spaceflight leads to reduced bone mineral density in weight bearing bones that is primarily attributed to a reduction in bone formation. We have previously demonstrated severely reduced osteoblastogenesis of human mesenchymal stem cells (hMSC) following 7 days culture in modeled microgravity (MMG). One potential mechanism for reduced osteoblastic differentiation is disruption of type I collagen (Col I)-integrin interactions and reduced integrin signaling. Integrins are heterodimeric transmembrane receptors that bind extracellular matrix (ECM) proteins and produce signals essential for proper cellular function, survival, and differentiation. Therefore, we investigated the effects of MMG on integrin expression and function in hMSC. We demonstrate that 7 days of culture in MMG leads to reduced expression of the ECM protein, Col I. Conversely, MMG consistently increases Col I-specific alpha2 and beta1 integrin protein expression. Despite this increase in integrin subunit expression, autophosphorylation of adhesion-dependent kinases, focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (PYK2), is significantly reduced. Activation of Akt protein kinase (Akt) is unaffected by the reduction in FAK activation. However, reduced downstream signaling via the Ras-mitogen activated protein kinase (MAPK) pathway is evidenced by a reduction in Ras and extracellular signal-related protein kinase (ERK) activation. Taken together, our findings indicate that MMG decreases integrin/MAPK signaling, which likely contributes to the observed reduction in osteoblastogenesis.

Differentiation of Mesenchymal Stem Cells towards a Nucleus Pulposus-like Phenotype Utilizing Simulated Microgravity In Vitro

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Mesenchymal stem cells (MSCs) were induced into a nucleus pulposus-like phenotype utilizing simulated microgravity in vitro in order to establish a new cell-based tissue engineering treatment for intervertebral disc degeneration. For induction of a nucleus pulposus-like phenotype, MSCs were cultured in simulated microgravity in a chemically defined medium supplemented with 0 (experimental group) and 10 ng/mL (positive control group) of transforming growth factor beta 1 (TGF-beta 1). MSCs cultured under conventional condition without TGF-beta 1 served as blank control group. On the day 3 of culture, cellular proliferation was determined by WST-8 assay. Differentiation markers were evaluated by histology and reverse transcriptase-polymerase chain reaction (RT-PCR). TGF-beta 1 slightly promoted the proliferation of MSCs. The collagen and proteoglycans were detected in both groups after culture for 7 days. The accumulation of proteoglycans was markedly increased. The RT-PCR revealed that the gene expression of Sox-9, aggrecan and type. collagen, which were chondrocyte specific, was increased in MSCs cultured under simulated microgravity for 3 days. The ratio of proteoglycans/collagen in blank control group was 3.4-fold higher than positive control group, which denoted a nucleus pulposus-like phenotype differentiation. Independent, spontaneous differentiation of MSCs towards a nucleus pulposus-like phenotype in simulated microgravity occurred without addition of any external bioactive stimulators, namely factors from TGF-beta family, which were previously considered necessary.

Related URLs:
<Go to ISI>://WOS:000291785900012

The influence of gravity on the process of development of animal systems

by cfynanon 9 June 2015in Biology & Biotechnology No comment

The development of animal systems is described in terms of a series of overlapping phases: pattern specification; differentiation; growth; and aging. The extent to which altered (micro) gravity (g) affects those phases is briefly reviewed for several animal systems. As a model, amphibian egg/early embryo is described. Recent data derived from clinostat protocols indicates that microgravity simulation alters early pattern specification (dorsal/ventral polarity) but does not adversely influence subsequent morphogenesis. Possible explanations for the absence of catastrophic microgravity effects on amphibian embryogenesis are discussed.

Effects of gravity perturbation on developing animal systems

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Developing systems provide unique opportunities for analyzing the effects of microgravity on animals. Several unusual types of cells as well as various extraordinary cellular behavior patterns characterize the embryos of most animals. Those features have been exploited as test systems for space flight. The data from previous experiments are reviewed, and considerations for the design of future experiments are presented. [References: 16]

Influence of simulated microgravity on avian primordial germ cell migration and reproductive capacity

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Fertilized eggs of chicken and quail were incubated under the simulated microgravity condition provided by a clinostat. The number of Primordial Germ Cells (PGCs) was counted in early embryogenesis, and the reproductive capacity of quail hatched following the simulated microgravity was investigated. Simulated microgravity caused significant decline of PGCs in the blood of early chicken embryos and in the gonads. The numbers of spermatogonia in the hatchling testis were also fewer than those in the control groups. Therefore, simulated microgravity may retard gonadial development and reduce the reproductive capacity. Copyright 2002 Wiley-Liss, Inc.

Effects of simulated microgravity on mammalian fertilization and preimplantation embryonic development in vitro

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Objective: To study the effects of simulated microgravity on mammalian fertilization and preimplantation embryonic development in vitro with the use of a horizontal clinostat device. Design: Controlled animal study. Setting: Research laboratory at a university medical school. Animal(s): B6D2F1 (C57BL/6 x DBA/2) and ICR mice between 8 and 10 weeks old. Intervention(s): The first experiment was performed to investigate whether gravity is required for fertilization in vitro under three conditions: clinostat rotation, rotational control, and stationary control. In the second experiment, one-cell embryos were cultured under each condition and their morphology and viability were assessed at 96 hours. Main Outcome Measure(s): The fertilized numbers and embryonic numbers at the morula and blastocyst stages were recorded in each condition. Result(s): In the first experiment, there were no statistically significant differences in the efficiency of achieving normal fertilization in vitro among the conditions. In the second experiment, there was a statistically significant decrease in the number of embryos reaching the morula and blastocyst stages after 96 hours in culture under clinostat rotation. Conclusion(s): These results suggest that the process of fertilization in vitro is not sensitive to the gravitational vector. However, the possibility exists that the frequency of early embryonic lethality is increased by microgravity. (Fertil Steril(R) 2000;74:1142-7. (C) 2000 by American Society for Reproductive Medicine).

Related URLs:
<Go to ISI>://WOS:000165897300014

24-hr blood pressure in HDT-bed rest and short-lasting space flight

by cfynanon 9 June 2015in Biology & Biotechnology No comment

In 2 ESA-cosmonauts we compared the 24-hr profiles in blood pressure (BP) and heart rate (HR) to those that we had observed in an earlier head-down tilted (HDT) bed rest study. In view of the lack of gravitational stress, an attenuated profile was expected, as in HDT. To obtain a full profile we measured automatic upper-arm cuff measurements in 2 cosmonauts, combined with PortapresTM recordings in one. Unlike HDT, actual microgravity did not result in attenuated circadian profiles. The levels of systolic and diastolic pressures tended to be slightly lower in flight. Only nighttime heart rate was significantly lower in Space.

Venous gas emboli and exhaled nitric oxide with simulated and actual extravehicular activity

by cfynanon 9 June 2015in Biology & Biotechnology No comment

The decompression experienced due to the change in pressure from a space vehicle (1013hPa) to that in a suit for extravehicular activity (EVA) (386hPa) was simulated using a hypobaric chamber. Previous ground-based research has indicated around a 50% occurrence of both venous gas emboli (VGE) and symptoms of decompression illness (DCI) after similar decompressions. In contrast, no DCI symptoms have been reported from past or current space activities. Twenty subjects were studied using Doppler ultrasound to detect any VGE during decompression to 386hPa, where they remained for up to 6h. Subjects were supine to simulate weightlessness. A large number of VGE were found in one subject at rest, who had a recent arm fracture; a small number of VGE were found in another subject during provocation with calf contractions. No changes in exhaled nitric oxide were found that can be related to either simulated EVA or actual EVA (studied in a parallel study on four cosmonauts). We conclude that weightlessness appears to be protective against DCI and that exhaled NO is not likely to be useful to monitor VGE.

Establishment of three-dimensional tissue-engineered bone constructs under microgravity-simulated conditions

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Bone constructs have been grown in vitro with use of isolated cells, biodegradable polymer scaffolds, and bioreactors. In our work, the relationships between the composition and mechanical properties of engineered bone constructs were studied by culturing bone marrow mesenchymal stem cells (BMSCs) on ceramic bovine bone scaffolds in different environments: static flasks and dynamic culture system in rotating vessels-which was a National Aeronautics and Space Administration-recommended, ground-based, microgravity-simulating system. After 15 days of cultivation, osteogenicity was determined according to DNA and alkaline phosphatase (ALP) analysis. DNA content and ALP were higher for cells grown on dynamic culture. Subsequently, the two kinds of engineered bone constructs were selected for transplantation into Sprague-Dawley rat cranial bone defects. After 24 weeks of in vivo implantation, the engineered bone constructs under dynamic culture were found to repair the defects better, with the engineered constructs showing histologically better bone connection. Thus, this dynamic system provides a useful in vitro model to construct the functional role and effects of osteogenesis in the proliferation, differentiation, and maturation of BMSCs. These findings suggest that the hydrodynamic microgravity conditions in tissue-culture bioreactors can modulate the composition, morphology, and function of the engineered bone.

WISE-2005: effect of aerobic and resistive exercises on orthostatic tolerance during 60 days bed rest in women

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Cardiovascular deconditioning after long duration spaceflight is especially challenging in women who have a lower orthostatic tolerance (OT) compared with men. We hypothesized that an exercise prescription, combining supine aerobic treadmill exercise in a lower body negative pressure (LBNP) chamber followed by 10 min of resting LBNP, three to four times a week, and flywheel resistive training every third day would maintain orthostatic tolerance (OT) in women during a 60-day head-down-tilt bed rest (HDBR). Sixteen women were assigned to two groups (exercise, control). Pre and post HDBR OT was assessed with a tilt/LBNP test until presyncope. OT time (mean +/- SE) decreased from 17.5 +/- 1.0 min to 9.1 +/- 1.5 min (-50 +/- 6%) in control group (P < 0.001) and from 19.3 +/- 1.3 min to 13.0 +/- 1.9 min (-35 +/- 7%) in exercise group (P < 0.001), with no significant difference in OT time between the two groups after HDBR (P = 0.13). Nevertheless, compared with controls post HDBR, exercisers had a lower heart rate during supine rest (mean +/- SE, 71 +/- 3 vs. 85 +/- 4, P < 0.01), a slower increase in heart rate and a slower decrease in stroke volume over the course of tilt/LBNP test (P < 0.05). Blood volume (mean +/- SE) decreased in controls (-9 +/- 2%, P < 0.01) but was maintained in exercisers (-4 +/- 3%, P = 0.17).Our results suggest that the combined exercise countermeasure did not significantly improve OT but protected blood volume and cardiovascular response to sub tolerance levels of orthostatic stress.

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Research Containing: Weightlessness Simulation

Modeled microgravity disrupts collagen I/integrin signaling during osteoblastic differentiation of human mesenchymal stem cells

Differentiation of Mesenchymal Stem Cells towards a Nucleus Pulposus-like Phenotype Utilizing Simulated Microgravity In Vitro

The influence of gravity on the process of development of animal systems

Effects of gravity perturbation on developing animal systems

Influence of simulated microgravity on avian primordial germ cell migration and reproductive capacity

Effects of simulated microgravity on mammalian fertilization and preimplantation embryonic development in vitro

24-hr blood pressure in HDT-bed rest and short-lasting space flight

Venous gas emboli and exhaled nitric oxide with simulated and actual extravehicular activity

Establishment of three-dimensional tissue-engineered bone constructs under microgravity-simulated conditions

WISE-2005: effect of aerobic and resistive exercises on orthostatic tolerance during 60 days bed rest in women