The effects of microgravity on stem cells and the new insights it brings to tissue engineering and regenerative medicine.

Conventional two-dimensional (2D) cell culture techniques may undergo modifications in the future, as life scientists have widely acknowledged the ability of three-dimensional (3D) in vitro culture systems to accurately simulate in vivo biology. In recent years, researchers have discovered that microgravity devices can address many challenges associated with 3D cell culture. Stem cells, being pluripotent cells, are regarded as a promising resource for regenerative medicine. Recent studies have demonstrated that 3D culture in microgravity devices can effectively guide stem cells towards differentiation and facilitate the formation of functional tissue, thereby exhibiting advantages within the field of tissue engineering and regenerative medicine. Furthermore, We delineate the impact of microgravity on the biological behavior of various types of stem cells, while elucidating the underlying mechanisms governing these alterations. These findings offer exciting prospects for diverse applications.

Simulated microgravity altered the gene expression profiles and inhibited the proliferation of Kupffer cells in the early phase by downregulating LMO2 and EZH2.

Microgravity is a primary challenge that need to overcome, when human travel to space. Our study provided evidence that Kupffer cells (KCs) are sensitive to simulated microgravity (SMG), and no similar research report has been found in the literature. Using transcriptome sequencing technology, it was showed that 631 genes were upregulated and 801 genes were downregulated in KCs after treatment under SMG for 3 days. The GO analysis indicated that the proliferation of KCs was affected when exposed to SMG for 3 days. CCK-8 assay confirmed that the proliferation of KCs was inhibited in the third day under the environment of SMG. Furthermore, we identified 8 key genes that affect the proliferation of KCs and predicted 2 transcription factors (TFs) that regulate the 8 key genes. Significantly, we found that microgravity could affect the expression of LMO2 and EZH2 to reduce the transcription of Racgap1, Ccna2, Nek2, Aurka, Plk1, Haus4, Cdc20, Bub1b, which resulting in the reduction in KCs proliferation. These finding suggested that the inhibition of KCs proliferation under microgravity may influence the homeostasis of liver, and LMO2 and EZH2 can be the targets in management of KCs' disturbance in the future practice of space medicine.

Simulated microgravity altered the proliferation, apoptosis, and extracellular matrix formation of L929 fibroblasts and the transforming growth factor-ß1/Smad3 signaling pathway.

Exposure to microgravity can adversely affect the fitness of astronauts. The integrity of the skin plays a crucial role in protecting against mechanical forces and infections, fluid imbalance, and thermal dysregulation. In brief, the skin wound may cause unknown challenges to the implementation of space missions. Wound healing is a physiological process that relies on the synergistic action of inflammatory cells, extracellular matrix (ECM), and various growth factors to maintain the integrity of skin after trauma. Fibroblasts are present almost throughout the entire process of wound repair, especially in the scar formation at the endpoint of wound healing. However, there is limited knowledge about the extent to which fibroblasts are affected by the lack of gravity during wound healing. In this study, we utilized the rotary cell culture system, a ground-based facility that mimics the weightless condition, to study the alterations of L929 fibroblast cells under simulated microgravity (SMG). Our results demonstrated that the SM condition exerted negative influences on the proliferation and ECM formation of the L929 fibroblast. Whereas, the apoptosis of fibroblast was significantly upregulated upon exposure to SMG conditions. Moreover, the transforming growth factor-ß1/Smad3 (TGF-ß1/smad3) signaling pathway of L929 fibroblast related to wound repair was also altered significantly under a weightless environment. Overall, our study provided evidence that fibroblasts are strongly sensitive to SMG and elucidated the potential value of the TGF-ß1/Smad3 signaling pathway modulating wound healing in the future practice of space medicine.

Autophagy in hepatic macrophages can be regulator and potential therapeutic target of liver diseases: A review.

Hepatic macrophages are a complex population of cells that play an important role in the normal functioning of the liver and in liver diseases. Autophagy, as a maintainer of cellular homeostasis, is closely connected to many liver diseases. And its roles are not always beneficial, but manifesting as a double-edged sword. The polarization of macrophages and the activation of inflammasomes are mediated by intracellular and extracellular signals, respectively, and are important ways for macrophages to take part in a variety of liver diseases. More attention should be paid to autophagy of hepatic macrophages in liver diseases. In this review, we focus on the regulatory role of hepatic macrophages' autophagy in a variety of liver diseases; especially on the upstream regulator of polarization and inflammasomes activation of the hepatic macrophages. We believe that the autophagy of hepatic macrophages can become a potential therapeutic target for management of liver diseases.

Proteomic analysis of the effects of simulated microgravity in human gastric mucosal cells.

Microgravity is an ecological factor that affects the environment of the body. In this study, quantitative isobaric labeling (tandem mass tag) method was used to study the changes in human gastric mucosal cells under simulated microgravity for the first time. Comparative proteomic analysis identified 394 (202 upregulated and 192 downregulated) and 542 (286 upregulated and 256 downregulated) proteins differentially regulated by simulated microgravity after 3 and 7 days, respectively. Then the identified proteins were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses for further exploration. The results of the analysis showed that the ribosomes of gastric mucosal cells were significantly impacted after exposure to simulated microgravity for 3 days, and the cells appeared to be in a state of stress and inflammation. Exposure to simulated microgravity for 7 days significantly affected the mitochondria of the cells, oxidative stress became more evident, while inflammation and weakened connections were observed in the cells. The results of this study highlighted the temporal response trend of gastric mucosal cells to the stressor of microgravity at the two time points of 3 and 7 days. These findings will provide insights into the development of methods to protect the gastric mucosa during space flight.

Correction to: Simulated microgravity significantly altered metabolism in epidermal stem cells.

The affiliation given for Yan Cui in this article is not correct. The following is the correction affiliation.

Effect of simulated microgravity on metabolism of HGC-27 gastric cancer cells.

The understanding into the pathogenesis and treatment of gastric cancer has improved in recent years; however, a number of limitations have delayed the development of effective treatment. Cancer cells can undergo glycolysis and inhibit oxidative phosphorylation in the presence of oxygen (Warburg effect). Previous studies have demonstrated that a rotary cell culture system (RCCS) can induce glycolytic metabolism. In addition, the potential of regulating cancer cells by targeting their metabolites has led to the rapid development of metabolomics. In the present study, human HGC-27 gastric cancer cells were cultured in a RCCS bioreactor, simulating weightlessness. Subsequently, liquid chromatography-mass spectrometry was used to examine the effects of simulated microgravity (SMG) on the metabolism of HGC-27 cells. A total of 67 differentially regulated metabolites were identified, including upregulated and downregulated metabolites. Compared with the normal gravity group, phosphatidyl ethanolamine, phosphatidyl choline, arachidonic acid and sphinganine were significantly upregulated in SMG conditions, whereas sphingomyelin, phosphatidyl serine, phosphatidic acid, L-proline, creatine, pantothenic acid, oxidized glutathione, adenosine diphosphate and adenosine triphosphate were significantly downregulated. The Human Metabolome Database compound analysis revealed that lipids and lipid-like metabolites were primarily affected in an SMG environment in the present study. Overall, the findings of the present study may aid our understanding of gastric cancer by identifying the underlying mechanisms of metabolism of the disease under SMG.

Simulated microgravity significantly altered metabolism in epidermal stem cells.

Simulated microgravity can significantly affect various cell types and multiple systems of the human body, such as cardiovascular system, skeletal muscle system, and immune system, and is known to cause anemia and loss of electrolyte and fluids. Epidermal stem cells (EpSCs) were cultured in a rotary cell culture system (RCCS) bioreactor to simulate microgravity. The metabolites of EpSCs were identified by liquid chromatography-mass spectrometry (LC-MS). Compared with normal gravity (NG) group, a total of 57 different metabolites of EpSCs were identified (P < 0.05, VIP > 1), including lipids and lipid-like molecules (51 molecules), amino acids (5 molecules), nucleosides, nucleotides, and analogues (1 molecule). According to the partial least squares discriminant analysis (PLS-DA) score plot, a VIP > 1 and P < 0.05 were obtained for the 57 different metabolites, of which 23 molecules were significantly downregulated and 34 were significantly upregulated in simulated microgravity (SMG) group. These results showed that SMG has a significant impact on different pathways, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that multiple pathways were involved, mainly the amino acid metabolism pathway, lipid metabolism pathway, membrane transport pathway, and cell growth and death pathways. Thus, the metabolic profile of EpSCs was changed under SMG. Exploring the metabolic profile of EpSCs would be helpful to further understand the growth characteristics of EpSCs under SMG, which will provide a new approach to explore the metabolomics mechanism of stress injury and repair trauma under SMG.

The effects of microgravity on the digestive system and the new insights it brings to the life sciences.

BACKGROUND: Weightlessness is a component of the complex space environment. It exerts adverse effects on the human body, and may pose unknown challenges to the implementation of space missions. The regular function of the digestive system is an important checkpoint for astronauts to conduct missions. Simulated microgravity can recreate the changes experienced by the human body in a weightless environment in space to a certain extent, providing technical support for the exploration of its mechanism and a practical method for other scientific research. METHODS AND MATERIALS: In the present study, we reviewed and discussed the latest research on the effects of weightlessness or simulated microgravity on the digestive system, as well as the current challenges and future expectations for progress in medical science and further space exploration. RESULTS: A series of studies have investigated the effects of weightlessness on the human digestive system. On one hand, weightlessness and the changing space environment may exert certain adverse effects on the human body. Studies based on cells or animals have demonstrated the complex effects on the human digestive system in response to weightlessness. On the other hand, a microgravity environment also facilitates the ideation of novel concepts for research in the domain of life science. CONCLUSION: The effects of weightlessness on the digestive system are considerably complicated. The emergence of methods that help simulate a weightless environment provides a more convenient alternative for assessing the impact and the mechanism underlying the effect of weightlessness on the human body. In addition, the simulated microgravity environment facilitates the ideation of novel concepts for application in regenerative medicine and other fields of life science.

Contrast-enhanced computed tomography findings of a huge perianal epidermoid cyst: A case report.

BACKGROUND: Epidermoid cysts can be found at any location in the human body. However, perianal epidermoid cysts are extremely rare and only a few cases have been reported. As far as we know, there is no special literature on the value of contrast-enhanced computed tomography (CT) for the diagnosis of perianal epidermoid cysts. CASE SUMMARY: A 60-year-old male patient presented to the department of general surgery of PLA Strategic Support Force Characteristic Medical Center with the chief complaint of a mass in the perianal region gradually expanding for more than 30 years and perianal discomfort upon sitting for a preceding period of 2 mo. Physical examination revealed a painless mass in the left perianal region. Contrast-enhanced CT was used for preoperative diagnosis. The patient was treated by total mass excision under epidural anesthesia. Postoperative pathological examination revealed the presence of a perianal epidermoid cyst. The patient showed a satisfactory recovery during the 6-month follow-up period. CONCLUSION: Contrast-enhanced CT may be a beneficial, useful, and convenient approach for assistance for preoperative diagnosis and surgical decision-making for patients with perianal epidermoid cysts.

Effect of Weightlessness on the 3D Structure Formation and Physiologic Function of Human Cancer Cells.

With the rapid development of modern medical technology and the deterioration of living environments, cancer, the most important disease that threatens human health, has attracted increasing concerns. Although remarkable achievements have been made in tumor research during the past several decades, a series of problems such as tumor metastasis and drug resistance still need to be solved. Recently, relevant physiological changes during space exploration have attracted much attention. Thus, space exploration might provide some inspiration for cancer research. Using on ground different methods in order to simulate microgravity, structure and function of cancer cells undergo many unique changes, such as cell aggregation to form 3D spheroids, cell-cycle inhibition, and changes in migration ability and apoptosis. Although numerous better experiments have been conducted on this subject, the results are not consistent. The reason might be that different methods for simulation have been used, including clinostats, random positioning machine (RPM) and rotating wall vessel (RWV) and so on. Therefore, we review the relevant research and try to explain novel mechanisms underlying tumor cell changes under weightlessness.

Novel treatment strategies for patients with HER2-positive breast cancer who do not benefit from current targeted therapy drugs.

Human epidermal growth factor receptor-2 positive breast cancer (HER2+ BC) is characterized by a high rate of metastasis and drug resistance. The advent of targeted therapy drugs greatly improves the prognosis of HER2+ BC patients. However, drug resistance or severe side effects have limited the application of targeted therapy drugs. To achieve more effective treatment, considerable research has concentrated on strategies to overcome drug resistance. Abemaciclib (CDK4/6 inhibitor), a new antibody-drug conjugate (ADC), src homology 2 (SH2) containing tyrosine phosphatase-1 (SHP-1) and fatty acid synthase (FASN) have been demonstrated to improve drug resistance. In addition, using an effective vector to accurately deliver drugs to tumors has shown good application prospects. Many studies have also found that natural anti-cancer substances produced effective results during in vitro and in vivo anti-HER2+ BC research. This review aimed to summarize the current status of potential clinical drugs that may benefit HER2+ BC patients in the future.

Effects of Huoxue Huayu Decoction combined with musculus pterygoideus lateralis closure on patients with temporomandibular joint dysfunction syndrome due to wind-cold stasis / 中成药

AIM To investigate the clinical effects of Huoxue Huayu Decoction (Angelicae sinensis Radix,Saposhnikoviae Radix,Schizonepetae Herba,etc.) combined with musculus pterygoideus lateralis closure in managing patients with temporomandibular joint dysfunction syndrome (TMJ) due to wind-cold stasis.METHODS From January 2015 to December 2015,68 cases of patients with TMJ due to wind-cold stasis identified and recruited by the department of stomatology of Hebei Provincial Hospital of Traditional Chinese Medicine were randomly assigned to treatment group and control group,each with 34 cases and given the musculus pterygoideus lateralis closure.But the treatment group was administered with an extra two-week adjuvant therapy of Huoxue Huayu Decoction,and generally one week such medication was taken as a therapeutic course.RESULTS After the intervention,the treatment group presented an overall better performance than the control group in terms of the open limit,NRS score,and the differences were statistically significant (P ＜ 0.05);and the values of CMI,PI,DI (P ＜0.05),in contrast to the not significantly varied values between the groups before the intervention (P ＞ 0.05).The treatment group also displayed its advantage if evaluated by TCM criteria,extent of the mandibular movementabnormalities,facial pain,temporomandibular joint sound or noise,irritability,sleeping difficulty,dark purple lips,tongue scores and wind-cold stasis scores (P ＜ 0.05).And generally a remarkably higher total effective rate was observed in the treatment group,and its difference to the control group was statistically significant (P ＜0.05).CONCLUSION Huoxue Huayu Decoction combined with conventional western medicinal approach in the management of TMJ due to wind-cold stasis can achieve a better therapeutic efficacy.

Risk of gastrointestinal complications in breast cancer patients treated with neratinib: a meta-analysis.

BACKGROUNDS: Neratinib is a potent EGFR/HER2 kinase inhibitor. Gastrointestinal complications (i.e. diarrhea, vomiting and nausea) are the most common adverse events. In this study, we aimed to investigate (1) the overall incidence and relative risk (RR) of diarrhea, vomiting and nausea and (2) whether combination neratinib therapy increased the incidence of gastrointestinal complications versus neratinib alone. METHODS: Relevant studies were identified from the PubMed database, from abstracts presented at the American Society of Clinical Oncology annual conference and from the Web of Science database. Incidences, RRs, and 95% confidence intervals (CIs) were calculated. RESULTS: The incidences of all-grade diarrhea, vomiting and nausea in the neratinib groups were 89% (95% CI = 77-95%), 31% (95% CI = 25-37%) and 44% (95% CI = 33-55%), respectively. The neratinib arms significantly increased the risk of diarrhea and vomiting in comparison with the control groups (diarrhea: all-grade, RR = 2.06, 95% CI = 1.38-3.08, P = 0.0004; grade 3/4, RR = 8.77, 95% CI = 2.91-26.40, P = 0.0001; vomiting: all-grade, RR = 2.02, 95% CI = 1.10-3.71, P = 0.02; grade 3/4, RR = 7.10, 95% CI = 3.33-15.15, P < 0.00001). CONCLUSIONS: Our meta-analysis demonstrates that the neratinib arms are associated with a significantly increased risk of diarrhea and vomiting.

Effects of repeated fasting/refeeding on lipid metabolism and uncoupling proteins expression in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the expression changes of mRNA and protein of uncoupling protein 2 (UCP2) in adipose tissues and uncoupling protein 3 (UCP3) in muscle tissues of rats which were treated with repeated fasting/refeeding and followed by fed with high-fat diet, and their possible mechanism on lipid metabolism.</p><p><b>METHODS</b>The model of repeating fasting/refeeding rats (repeated cycles of 1-day fasting and 1-day refeeding for 6 weeks fed with common-fat diet, RFR) was designed. At the end of the 6th week, the RFR rats were switched to high-fat diet every day (RFR-CF/HF). Moreover, the control rats were randomly divided into two groups and then fed with high-fat diet (HF) and common-fat diet (CF) respectively for 6 weeks. All rats were killed at the end of the 6th and the 12th week, serum and plasma samples were taken from abdominal aorta, and then the concentration of serum lipids, glucose, free fatty acid (FFA), and plasma insulin were measured. The histomorphological changes of liver tissues were observed by HE staining. The expression level of mRNA and protein of UCP2 in adipose tissues and UCP3 in muscle tissues was respectively measured by RT-PCR and Western blot.</p><p><b>RESULTS</b>(1) The concentration of serum glucose in RFR group was significantly lower than that in control group (P < 0.05), while the concentration of serum FFA, expression level of UCP2 mRNA, UCP3 mRNA and protein were significantly higher than those in control group (P < 0.05). (2) The concentration of serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and plasma insulin in RFR-CF/HF group was significantly lower than that in HF group, but significantly higher than that in CF group (P < 0.05). The concentration of serum FFA was significantly lower than that of HF and CF groups (P < 0.01). The expression level in UCP2, UCP3 mRNA and protein was significantly higher than that of HF group, but significantly lower than that of CF group (P < 0.05).</p><p><b>CONCLUSION</b>The feeding pattern of repeated fasting/refeeding can decrease the obese degree induced by high-fat diet, increase the mRNA and protein expression of UCP2 in adipose tissues and UCP3 in muscle tissues, up-regulate the proton leak caused by obesity, and improve the rate of basic energy metabolism in rats.</p>

Sclerotherapy of simple hepatic cysts by repeated aspiration and alcohol instillation.

BACKGROUND/AIMS: The efficacy and safety of traditional alcohol sclerotherapy procedures are controversial in the management of large simple hepatic cysts. In this study, we aimed to develop and evaluate a novel alcohol sclerotherapy procedure, termed repeated aspiration and alcohol instillation sclerotherapy, for the treatment of simple hepatic cysts. MATERIALS AND METHODS: A prospective, double-blind, randomized study was performed. Sixty-seven patients with large simple hepatic cysts were randomized into two groups to receive either single-session alcohol retention sclerotherapy (alcohol was instilled into the cyst cavity, kept for 20 minutes and aspirated) or repeated aspiration and alcohol instillation sclerotherapy (instillation of 30-70 ml of alcohol and immediate aspiration with repetition 3 to 6 times until the estimated alcohol concentration exceeded 80%). The cyst volume reduction was calculated to compare the efficacy of the two procedures. We evaluated the safety of the procedure by monitoring side effects and assaying blood alcohol concentrations at 0, 0.5, 1, 2 and 3 hours after sclerotherapy. RESULTS: The cyst volume reduction in patients undergoing repeated aspiration and alcohol instillation sclerotherapy was significantly higher than that in those receiving alcohol-retention sclerotherapy. The concentration of alcohol in the last aspirated cyst fluid was correlated with the mean volume reduction in patients undergoing repeated aspiration and alcohol instillation sclerotherapy but not in the alcohol-retention group. Only minor side effects occurred in both groups. Although elevated blood alcohol concentration was noted in all patients, it declined to normal levels within 2-3 hours after treatment. There were no significant differences in blood alcohol concentration between the two groups. CONCLUSIONS: Repeated aspiration and alcohol instillation sclerotherapy is superior to single-session alcohol-retention sclerotherapy in the management of large simple hepatic cysts.

Effects of α-lipoic acid and vitamin C on oxidative stress in rat exposed to chronic arsenic toxicity / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore arsenic-induced oxidative stress and the protective efficacy of α-lipoic acid and vitamin c.</p><p><b>METHODS</b>50 male SD rats were randomly divided into 5 groups. Ten rats (the control group) were exposed to deionized water for 6 weeks, and the others were alone exposed to sodium arsenite (50 mg/L water) for 6 weeks, at the same time, three group rats were administered intragastrically (i.g.) with α-lipoic acid 10 mg×kg(-1)×d(-1) and vitamin C 25 mg×kg(-1)×d(-1) either alone or in combination. At the end of experiment, blood was drawn from abdominal aorta, and then the blood, brain and liver of rats were used for biochemical assays, including blood glutathione (GSH), δ-aminolevulinic acid dehydratase (δ-ALAD ), reactive oxygen species (ROS) and oxidized glutathione (GSSG) level. At the same time, the super oxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, catalase (CAT) activity, ATPase activity of brain and liver were determined. The caspase activity of brain were also determined.</p><p><b>RESULTS</b>There were a significant increase in ROS level (P < 0.05), but a significant decrease in δ-ALAD activity (P < 0.01) in the chronic arsenic toxicity model group compared with the control group. These alterations were marginally restored by co-administration of vitamin C and α-lipoic acid individually, while significant recovery was observed in the animals supplemented with both the antioxidants together with arsenite in rat (P < 0.05). At the same time, there was a significant increase in the ROS and TBARS level of the brain and liver (P < 0.05), and caspase activity of the brain (P < 0.05), while there was a significant decrease in antioxidant enzymes and ATPase activity on arsenite exposure in rats (P < 0.05). These alterations were also marginally restored by co-administration of vitamin C and α-lipoic acid individually, while significant recovery was observed in the animals supplemented with both the antioxidants together with arsenite in rat (P < 0.05).</p><p><b>CONCLUSIONS</b>Arsenite-induced oxidative stress can be significantly protected by co-administration of α-lipoic acid and vitamin C individually, but the best effects could be observed with combined administration of two antioxidants during arsenite exposure in animals. The dietary intervention of or supplementation with natural dietary nutrients is possible to prevent the effects of arsenic in populations of risk.</p>

Effect of platelet-derived growth factor and lysosomes of lung injury in macaque with early-phase endotoxic shock / 中华急诊医学杂志

Objective To study the effect of platelet-derived growth factor(PDGF)and lysosomes on lung injury in macaque with early-phase endotoxie shock.Method Eleven macaques were randomly divided into two groups,namely,control group(Co group,n=5)iand endotoxic group(En group,n=6).The macaque of the Co group injected with 1 ml/kg normal saline and the macque of the En group received a dose of 2.8 mg/kg Lipopolysaccharides(LPS)i.v.The blood gas was detected at 120 minutes after LPS challenging. Uhrastructure,cytochemistry of acid phosphatase(ACPase)detection by electronic microscopy and immunohistochemical assay of PDGF were completed in hmgs of all the macaque .Results Administration of LPS did not change the parameters of gas exchange,namely,PaO_2,PaO_2/Fi and PaCO_2.In the early phase,of endotoxic shock,ACPase activity products increased and lysosome destroyed in the alveolar cells.The pathologic changes of alveolus,such as degeneration of vessel endothelium,injury of alveolar epithelium and damage of basement membrane,and transudation of blood component were observed by electron microscopy in the En group. However,no pathological changes were found in the control group.By immunohistochemical staining,PDGF on alveolar wall in the En animals was observed,whereas no PDGF protein in the Co macaques was noticed. Conclusions Administration of LPS induced the expression of PDGF in the alveolar wall and lysosome injury in the alveolar cells,as a result of alveolar damage in early-phase endotoxin shock.In the meantime,the parameters of gas exchanges did not change.The PDGF may play an important role in the pathogenesis of lung during the early-phase of endotoxin shock.