Long-term osteogenic differentiation of human bone marrow stromal cells in simulated microgravity: novel proteins sighted.

Microgravity-induced bone loss is a major concern for space travelers. Ground-based microgravity simulators are crucial to study the effect of microgravity exposure on biological systems and to address the limitations posed by restricted access to real space. In this work, for the first time, we adopt a multidisciplinary approach to characterize the morphological, biochemical, and molecular changes underlying the response of human bone marrow stromal cells to long-term simulated microgravity exposure during osteogenic differentiation. Our results show that osteogenic differentiation is reduced while energy metabolism is promoted. We found novel proteins were dysregulated under simulated microgravity, including CSC1-like protein, involved in the mechanotransduction of pressure signals, and PTPN11, SLC44A1 and MME which are involved in osteoblast differentiation pathways and which may become the focus of future translational projects. The investigation of cell proteome highlighted how simulated microgravity affects a relatively low number of proteins compared to time and/or osteogenic factors and has allowed us to reconstruct a hypothetical pipeline for cell response to simulated microgravity. Further investigation focused on the application of nanomaterials may help to increase understanding of how to treat or minimize the effects of microgravity.

Combined Exposure to Simulated Microgravity and Acute or Chronic Radiation Reduces Neuronal Network Integrity and Survival.

During orbital or interplanetary space flights, astronauts are exposed to cosmic radiations and microgravity. However, most earth-based studies on the potential health risks of space conditions have investigated the effects of these two conditions separately. This study aimed at assessing the combined effect of radiation exposure and microgravity on neuronal morphology and survival in vitro. In particular, we investigated the effects of simulated microgravity after acute (X-rays) or during chronic (Californium-252) exposure to ionizing radiation using mouse mature neuron cultures. Acute exposure to low (0.1 Gy) doses of X-rays caused a delay in neurite outgrowth and a reduction in soma size, while only the high dose impaired neuronal survival. Of interest, the strongest effect on neuronal morphology and survival was evident in cells exposed to microgravity and in particular in cells exposed to both microgravity and radiation. Removal of neurons from simulated microgravity for a period of 24 h was not sufficient to recover neurite length, whereas the soma size showed a clear re-adaptation to normal ground conditions. Genome-wide gene expression analysis confirmed a modulation of genes involved in neurite extension, cell survival and synaptic communication, suggesting that these changes might be responsible for the observed morphological effects. In general, the observed synergistic changes in neuronal network integrity and cell survival induced by simulated space conditions might help to better evaluate the astronaut's health risks and underline the importance of investigating the central nervous system and long-term cognition during and after a space flight.

Microgravity-driven remodeling of the proteome reveals insights into molecular mechanisms and signal networks involved in response to the space flight environment.

Space is a hostile environment characterized by high vacuum, extreme temperatures, meteoroids, space debris, ionospheric plasma, microgravity and space radiation, which all represent risks for human health. A deep understanding of the biological consequences of exposure to the space environment is required to design efficient countermeasures to minimize their negative impact on human health. Recently, proteomic approaches have received a significant amount of attention in the effort to further study microgravity-induced physiological changes. In this review, we summarize the current knowledge about the effects of microgravity on microorganisms (in particular Cupriavidus metallidurans CH34, Bacillus cereus and Rhodospirillum rubrum S1H), plants (whole plants, organs, and cell cultures), mammalian cells (endothelial cells, bone cells, chondrocytes, muscle cells, thyroid cancer cells, immune system cells) and animals (invertebrates, vertebrates and mammals). Herein, we describe their proteome's response to microgravity, focusing on proteomic discoveries and their future potential applications in space research. BIOLOGICAL SIGNIFICANCE: Space experiments and operational flight experience have identified detrimental effects on human health and performance because of exposure to weightlessness, even when currently available countermeasures are implemented. Many experimental tools and methods have been developed to study microgravity induced physiological changes. Recently, genomic and proteomic approaches have received a significant amount of attention. This review summarizes the recent research studies of the proteome response to microgravity inmicroorganisms, plants, mammalians cells and animals. Current proteomic tools allow large-scale, high-throughput analyses for the detection, identification, and functional investigation of all proteomes. Understanding gene and/or protein expression is the key to unlocking the mechanisms behind microgravity-induced problems and to finding effective countermeasures to spaceflight-induced alterations but also for the study of diseases on earth. Future perspectives are also highlighted.

Adjuvant chemoradiotherapy in gastric cancer: a pooled analysis of the AIRO gastrointestinal group experience.

BACKGROUND: Given the poor compliance with adjuvant chemoradiotherapy (CRT) in gastric cancer reported in previous studies, a survey was conducted among 18 Italian institutions within the AIRO Gastrointestinal Group to investigate current treatment modalities, toxicities, and compliance with adjuvant CRT. PATIENTS AND METHODS: Data from 348 patients operated on for gastric cancer were collected retrospectively from September 2000 to June 2008 and analyzed. The adjuvant treatments included CRT according to center guidelines. In multivariate analysis, acute hematological, gastrointestinal, and renal toxicity (according to the RTOG Acute Radiation Morbidity Scoring Criteria) and compliance with treatment were studied, as well as risk factors for local control, metastasis-free survival, disease-free survival, and overall survival. RESULTS: Compliance with treatment was excellent: 95.7% of patients completed CRT. During CRT, acute G3-G4 ­hematological toxicity was 3.7% and acute G3-G4 gastrointestinal toxicity 4%. 78.4% of patients completed chemotherapy (CT), either before or after CRT. During CT acute G3-G4 hematological toxicity was 5.4% and acute G3-G4 gastrointestinal toxicity 6%. Overall, 74.1% of patients completed the prescribed treatment (CRT and CT). Doses greater than 4500 cGy did not compensate for more aggressive disease. The 5-year overall survival was 51%. CONCLUSIONS: The adjuvant treatment of gastric cancer within the AIRO group was diverse, but radiotherapy treatment was homogeneous (in terms of technique) and well tolerated. Toxicity was low and compliance with treatment was good during CRT; these results may be due to the radiotherapy technique applied. This survey could be used as a benchmark for further studies.

Identification of novel radiation-induced p53-dependent transcripts extensively regulated during mouse brain development.

Ionizing radiation is a potent activator of the tumor suppressor gene p53, which itself regulates the transcription of genes involved in canonical pathways such as the cell cycle, DNA repair and apoptosis as well as other biological processes like metabolism, autophagy, differentiation and development. In this study, we performed a meta-analysis on gene expression data from different in vivo and in vitro experiments to identify a signature of early radiation-responsive genes which were predicted to be predominantly regulated by p53. Moreover, we found that several genes expressed different transcript isoforms after irradiation in a p53-dependent manner. Among this gene signature, we identified novel p53 targets, some of which have not yet been functionally characterized. Surprisingly, in contrast to genes from the canonical p53-regulated pathways, our gene signature was found to be highly enriched during embryonic and post-natal brain development and during in vitro neuronal differentiation. Furthermore, we could show that for a number of genes, radiation-responsive transcript variants were upregulated during development and differentiation, while radiation non-responsive variants were not. This suggests that radiation exposure of the developing brain and immature cortical neurons results in the p53-mediated activation of a neuronal differentiation program. Overall, our results further increase the knowledge of the radiation-induced p53 network of the embryonic brain and provide more evidence concerning the importance of p53 and its transcriptional targets during mouse brain development.

Repeated intratracheal instillation of PM10 induces lipid reshaping in lung parenchyma and in extra-pulmonary tissues.

Adverse health effects of air pollution attributed mainly to airborne particulate matter have been well documented in the last couple of decades. Short term exposure, referring to a few hours exposure, to high ambient PM10 concentration is linked to increased hospitalization rates for cardiovascular events, typically 24 h after air pollution peaks. Particulate matter exposure is related to pulmonary and cardiovascular diseases, with increased oxidative stress and inflammatory status. Previously, we have demonstrated that repeated intratracheal instillation of PM10sum in BALB/c mice leads to respiratory tract inflammation, creating in lung a condition which could potentially evolve in a systemic toxic reaction. Additionally, plasma membrane and tissue lipids are easily affected by oxidative stress and directly correlated with inflammatory products. With this aim, in the present investigation using the same model, we analyzed the toxic potential of PM10sum exposure on lipid plasma membrane composition, lipid peroxidation and the mechanisms of cells protection in multiple organs such as lung, heart, liver and brain. Obtained results indicated that PM10 exposure led to lung lipid reshaping, in particular phospholipid and cholesterol content increases; concomitantly, the generation of oxidative stress caused lipid peroxidation. In liver we found significant changes in lipid content, mainly due to an increase of phosphatidylcholine, and in total fatty acid composition with a more pronounced level of docosahexaenoic acid; these changes were statistically correlated to lung molecular markers. Heart and brain were similarly affected; heart was significantly enriched in triglycerides in half of the PM10sum treated mice. These results demonstrated a direct involvement of PM10sum in affecting lipid metabolism and oxidative stress in peripheral tissues that might be related to the serious systemic air-pollution effects on human health.

MorphoNeuroNet: an automated method for dense neurite network analysis.

High content cell-based screens are rapidly gaining popularity in the context of neuronal regeneration studies. To analyze neuronal morphology, automatic image analysis pipelines have been conceived, which accurately quantify the shape changes of neurons in cell cultures with non-dense neurite networks. However, most existing methods show poor performance for well-connected and differentiated neuronal networks, which may serve as valuable models for inter alia synaptogenesis. Here, we present a fully automated method for quantifying the morphology of neurons and the density of neurite networks, in dense neuronal cultures, which are grown for more than 10 days. MorphoNeuroNet, written as a script for ImageJ, Java based freeware, automatically determines various morphological parameters of the soma and the neurites (size, shape, starting points, and fractional occupation). The image analysis pipeline consists of a multi-tier approach in which the somas are segmented by adaptive region growing using nuclei as seeds, and the neurites are delineated by a combination of various intensity and edge detection algorithms. Quantitative comparison showed a superior performance of MorphoNeuroNet to existing analysis tools, especially for revealing subtle changes in thin neurites, which have weak fluorescence intensity compared to the rest of the network. The proposed method will help determining the effects of compounds on cultures with dense neurite networks, thereby boosting physiological relevance of cell-based assays in the context of neuronal diseases.

Postoperative 5-FU based radiochemotherapy in rectal cancer: retrospective long term results and prognostic factors of a pooled analysis on 1,338 patients.

AIM: To evaluate survival outcomes of patients in pStage II-III rectal cancer treated with adjuvant 5-fluorouracil-based radiochemotherapy and to retrospectively analyze the impact of prognostic variables on local control, metastasis-free survival and cause-specific survival. PATIENTS AND METHODS: A total of 1,338 patients, treated between 1985-2005 for locally advanced rectal cancer, who underwent surgery and postoperative 5-fluorouracil-based chemoradiation, were selected. RESULTS: The actuarial 5- and 10-year outcomes were: local control 87.0%-84.1%, disease-free survival 61.6%-52.1%, metastasis-free survival 72.0%-67.2%, cause-specific survival 70.4%-57.5%, and overall survival 63.8%-53.4%. Better outcomes were observed in patients with IIA, IIIA stage. Multivariate analyses showed that variables significantly affecting metastasis-free survival were pT4 and pN2, while for cancer-specific survival those variables were age >65 years, pT4, pN1, pN2, distal tumors and number of lymph nodes removed ≤ 12. CONCLUSION: This study confirmed that among stage II-III rectal cancer patients there are subgroups of patients with different clinical outcomes.

Morphological and physiological changes in mature in vitro neuronal networks towards exposure to short-, middle- or long-term simulated microgravity.

One of the objectives of the current international space programmes is to investigate the possible effects of the space environment on the crew health. The aim of this work was to assess the particular effects of simulated microgravity on mature primary neuronal networks and specially their plasticity and connectivity. For this purpose, primary mouse neurons were first grown for 10 days as a dense network before being placed in the Random Positioning Machine (RPM), simulating microgravity. These cultures were then used to investigate the impact of short- (1 h), middle- (24 h) and long-term (10 days) exposure to microgravity at the level of neurite network density, cell morphology and motility as well as cytoskeleton properties in established two-dimensional mature neuronal networks. Image processing analysis of dense neuronal networks exposed to simulated microgravity and their subsequent recovery under ground conditions revealed different neuronal responses depending on the duration period of exposure. After short- and middle-term exposures to simulated microgravity, changes in neurite network, neuron morphology and viability were observed with significant alterations followed by fast recovery processes. Long exposure to simulated microgravity revealed a high adaptation of single neurons to the new gravity conditions as well as a partial adaptation of neuronal networks. This latter was concomitant to an increase of apoptosis. However, neurons and neuronal networks exposed for long-term to simulated microgravity required longer recovery time to re-adapt to the ground gravity. In conclusion, a clear modulation in neuronal plasticity was evidenced through morphological and physiological changes in primary neuronal cultures during and after simulated microgravity exposure. These changes were dependent on the duration of exposure to microgravity.

Non-conventional apoptotic response to ionising radiation mediated by N-methyl D-aspartate receptors in immature neuronal cells.

During cortical development, N-methyl D-aspartate (NMDA) receptors are highly involved in neuronal maturation and synapse establishment. Their implication in the phenomenon of excitotoxicity has been extensively described in several neurodegenerative diseases due to the permissive entry of Ca2+ ions and massive accumulation in the intracellular compartment, which is highly toxic to cells. Ionising radiation is also a source of stress to the cells, particularly immature neurons. Their capacity to induce cell death has been described for various cell types either by directly damaging the DNA or indirectly through the generation of reactive oxygen species responsible for the activation of a battery of stress response effectors leading in certain cases, to cell death. In this study, in order to determine whether a link exists between NMDA receptors-mediated excitotoxicity and radiation-induced cell death, we evaluated radiation-induced cell death in vitro and in vivo in maturing neurons during the fetal period. Cell death induction was assessed by TUNEL, caspase-3 activity and DNA ladder assays, with or without the administration of dizocilpine (MK-801), a non-competitive NMDA receptor antagonist which blocks neuronal Ca2+ influx. To further investigate the possible involvement of Ca2+-dependent enzyme activation, known to occur at high Ca2+ concentrations, we examined the protective effect of a calpain inhibitor on cell death induced by radiation. Doses ranging from 0.2 to 0.6 Gy of X-rays elicited a clear apoptotic response that was prevented by the injection of dizocilpine (MK-801) or calpain inhibitor. These data demonstrate the involvement of NMDA receptors in radiation-induced neuronal death by the activation of downstream effectors, including calpain-related pathways. An increased apoptotic process elicited by radiation, occurring independently of the normal developmental scheme, may eliminate post-mitotic but immature neuronal cells and deeply impair the establishment of the neuronal network, which in the case of cortical development is critical for cognitive capacities.

Cystic hydatidosis: a rare case of spine localization.

Cystic hydatidosis is a zoonosis endemic both to Sicily and other Mediterranean areas. Generally, Echinococcus granulosus tapeworms develop in the liver, lung and less frequently in the peritoneum, spleen or kidney. We present a rare case of spinal hydatid disease. The patient was a 38-year-old housewife with a vertebral echinococcosis revealed by acute paraplegia of the legs. Medical treatment with albendazole and surgical intervention improved the clinical symptoms. This case is emblematic both for the unusual localization and for the need of a multidisciplinary approach for diagnosing and monitoring suspected hydatid lesions. Patients with suspected abdominal or lung echinococcosis should also be investigated for other localizations such as the brain, spine and heart. Furthermore, in endemic areas hydatidosis must be suspected in the presence of lesions occupying space in these districts.

Space flight affects motility and cytoskeletal structures in human monocyte cell line J-111.

Certain functions of immune cells in returning astronauts are known to be altered. A dramatic depression of the mitogenic in vitro activation of human lymphocytes was observed in low gravity. T-cell activation requires the interaction of different type of immune cells as T-lymphocytes and monocytes. Cell motility based on a continuous rearrangement of the cytoskeletal network within the cell is essential for cell-cell contacts. In this investigation on the International Space Station we studied the influence of low gravity on different cytoskeletal structures in adherent monocytes and their ability to migrate. J-111 monocytes were incubated on a colloid gold substrate attached to a cover slide. Migrating cells removed the colloid gold, leaving a track recording cell motility. A severe reduction of the motility of J-111 cells was found in low gravity compared to 1g in-flight and ground controls. Cell shape appeared more contracted, whereas the control cells showed the typical morphology of migrating monocytes, i.e., elongated and with pseudopodia. A qualitative and quantitative analysis of the structures of F-actin, ß-tubulin and vinculin revealed that exposure of J-111 cells to low gravity affected the distribution of the different filaments and significantly reduced the fluorescence intensity of F-actin fibers. Cell motility relies on an intact structure of different cytoskeletal elements. The highly reduced motility of monocytes in low gravity must be attributed to the observed severe disruption of the cytoskeletal structures and may be one of the reasons for the dramatic depression of the in vitro activation of human lymphocytes.

The role of brachytherapy in the management of oropharyngeal carcinomas: the Trento experience.

AIMS: This study was undertaken to determine the outcome of patients with oropharyngeal cancer treated at the Radiotherapy Department of the Santa Chiara Hospital (Trento, Italy) with brachytherapy alone or combined with external beam radiotherapy (EBRT). MATERIAL AND METHODS: We retrospectively reviewed the medical records of 87 patients with squamous cell carcinoma of the oropharynx treated by radiation therapy between January 1986 and September 1999. The median age was 59 years and all patients had a minimum follow-up of one year. Tumor locations were 46 tonsillar region, 31 soft palate and 10 base of the tongue. The patients were staged as follows: 41 T1, 35 T2, 11 T3 with 70 N0, 9 N1 and 8 N2. They received either brachytherapy alone (14 patients) or a combination of external beam irradiation and brachytherapy (73 patients) using an afterloading iridium technique in a plastic tube. RESULTS: Overall primary tumor control, including salvage surgery, was 81/87 (93%). Control of metastatic cervical adenopathy was as follows: clinical stage N1, 5/9 patients; N2, 2/8 patients. The estimated five-year cause-specific survival and overall survival rates were 81% and 47%, respectively. After interstitial irradiation severe complications were limited to one case of osteoradionecrosis of the mandible and seven cases of mucosal ulcer. CONCLUSION: This study confirms that iridium-192 interstitial implant alone or as a boost after external beam irradiation is a safe and effective therapy in the management of oropharyngeal carcinomas.