Tuberous sclerosis complex associated lymphangioleiomyomatosis caused by de novo mutation of TSC2 gene in Vietnam: A case report.

Lymphangioleiomyomatosis (LAM) represents a rare, insidiously progressive disease of the pulmonary system, marked by cystic degradation of lung tissues leading to respiratory compromise. Pulmonary LAM has been identified as being associated with tuberous sclerosis complex (TSC) in its pulmonary manifestation (TSC-LAM), a multisystem genetic disorder resulting from mutations in either the TSC1 or TSC2 genes. Herein, we describe an early 20s female admitted to the hospital with dyspnea, chest pain, hypopigmented macules, and facial fibroadenomas. She has a medical history of renal angiomyolipomas (ALMs) and pneumothoraces. Diagnosis with LAM was confirmed through high-resolution computed tomography (HRCT) scan and histopathology of lung biopsy. Whole exome sequencing analysis identified a frameshift mutation c.4504del (p.L1502Cfs*74) in the patient's TSC2 gene. This variant was de novo due to its absence in the patient's parents. This is the first report on the clinical and genetic etiology of TSC-LAM in Vietnam.

Characterization of a BAC transgenic mouse expressing Krt19-driven iCre recombinase in its digestive organs.

Cytokeratin 19 (KRT19) protein is highly expressed in the epithelium of the gastrointestinal (GI) tract, hepatobiliary tissues, and pancreas of humans and mice. In the present study, we used an improved Cre (iCre) gene to enhance the efficiency of Cre expression in mammalian cells. We established a new transgenic Krt19-iCre bacterial artificial chromosome (BAC) mouse model using the BAC recombineering strategy. Site-specific iCre expression pattern was examined in embryos, adults, and elderly Krt19-iCre mice crossed with Tomato or LacZ reporter mice. Both iCre and reporter protein expressions in adult Krt19-iCre;Tomatoflox/+ (Krt19-iCre Tomato reporter) mice were observed mainly in the epithelial cells of the GI tract, hepatobiliary tissues, and pancreas. However, the expression in the intrahepatic and small pancreatic duct were lower than those in the common bile and large pancreatic duct. In the Krt19-iCre; LacZ reporter embryos, ß-galactosidase for the LacZ reporter was expressed in the glandular epithelial cells of the GI tract in 9.5-day embryos, 12-day embryos, and newborn mice. The reporter protein expression in Krt19-iCre-Tomato reporter mice was consistent with the KRT19 expression in human GI tissues. In conclusion, Krt19-iCre BAC transgenic mice can be used to investigate developmental and pathological conditions using the iCre-loxP system.

Time-sensitive effects of hypoxia on differentiation of neural stem cells derived from mouse embryonic stem cells in vitro.

OBJECTIVES: Oxygen tension is an important component of microenvironment for the differentiation of embryonic stem cells including neural lineage. However, the comprehensive influence of hypoxia on neural differentiation during embryonic neural development has not yet been examined. METHODS: In this study, we investigated the effect of low oxygen levels (5% O(2)), or hypoxia, in two stages of neural differentiation in vitro: (1) inducing mouse embryonic stem cells into neural stem cells (NSCs); and then (2) inducing NSCs into neural progenitor cells in neurospheres. RESULTS: In the first stage, NSCs generation was reduced under hypoxia. Less mature morphological changes (including neural marker) of NSCs were observed, suggesting the prevention of early differentiation under hypoxic conditions. Thus undifferentiated stem cells were maintained in this stage. However, in the second stage, hypoxia induced neural differentiation in neurospheres. Nevertheless, non-neural progenitor cell formation, such as mesoderm progenitor cell lines or epithelial cell lines, was restricted by low oxygen tension. DISCUSSIONS: Our results demonstrate that hypoxia is essential for regulating neural differentiation and show the different effects on NSC differentiation dependent on the time-course of NSC development. In the early stage of NSCs induction, hypoxia inhibits neural differentiation and maintains the undifferentiated state; in the later stage of NSCs induction, hypoxia induces neural differentiation. Our study may contribute to the development of new insights for expansion and control of neural differentiation.

Sivelestat improves outcome of crush injury by inhibiting high-mobility group box 1 in rats.

Severe crush injury is associated with high mortality because of resulting hyperkalemia in early phase and multiorgan dysfunction in later phase. In this study, we investigated the effects of sivelestat administration 1 h before reperfusion on the outcome of crush injury. Crush injury was induced by 6 h of direct compression to both hindlimbs of anesthetized rats with blocks weighing 3.5 kg each side, followed by 3 h of reperfusion. Rats were randomly assigned to three groups. In the control group, rats were infused with normal saline at 1 mL/kg per hour throughout the experiment without compression. Rats in the positive control group were compressed for 6 h, followed by fluid resuscitation initiated 1 h before release with normal saline. The infusion rate was increased from 1 to 10 mL/kg per hour and continued for 4 h. Rats in the treated group underwent the same procedures as in the positive control group, but sivelestat was added to normal saline (concentration was adjusted to infuse 10 mg/kg per hour) during fluid resuscitation (for 4 h). Treatment with sivelestat significantly improved survival rate with P = 0.032. This was accompanied by lower serum high-mobility group box 1 (HMGB1) levels after 3-h reperfusion, attenuated lung injury (assessed using hematoxylin-eosin stain), and suppression of HMGB1 expression in the lung and the liver. These results suggest that treatment with sivelestat improves the outcome of crush injury, likely by inhibiting HMGB1 in rats.

Galectin-3 in preneoplastic lesions of glioma.

Gliomas are the most common primary brain tumors in adults and have a poor prognosis. Galectin-3 is a ß-galactosidase-binding lectin which is important in pre-mRNA splicing, regulation of cell proliferation, cell adhesion and apoptosis. Although galectin-3 has been shown as a glioma related marker and expression of galectin-3 has been reported to correlate with WHO grade in human gliomas, expression of galectin-3 in early neoplastic lesions such as early neoplastic proliferation (ENP) and microtumor is still far from fully understood. In the present study, expression of galectin-3 in ethylnitrosourea-induced rat gliomas including preneoplastic and neoplastic lesions was examined by immunohistochemistry for galectin-3, Iba-1 (a specific microglial cell marker), GFAP (a specific astrocyte cell marker), and conventional hematoxylin and eosin staining (for morphological observation). The results showed that exact location of ENP was detected clearly by galectin-3 immunohistochemistry whereas normal brain tissues were negative. In ENP and microtumor, galectin-3 was expressed in neoplastic astrocytic cells but rarely in microglia. In malignant glioma, however, galectin-3 was expressed in both neoplastic astrocytic cells and microglia. This suggests that galectin-3 is activated in microglia and macrophages according to the progression of glioma. Galectin-3 was not expressed in oligodendrocytic cells. Our results indicate that galectin-3 is a good specific marker indicating the early stage of glioma tumorigenesis.

Increase of galectin-3 expression in microglia by hyperthermia in delayed neuronal death of hippocampal CA1 following transient forebrain ischemia.

The ischemic damage in the hippocampal CA1 region following transient forebrain ischemia, delayed neuronal death, is a typical apoptotic response, but the underlying mechanisms are not fully understood. We have reported that mild hyperthermia (38 °C) accelerates DNA fragmentation of the gerbil CA1 pyramidal neurons following transient forebrain ischemia. Recently, we reported that galectin-3, a ß-galactosidase-binding lectin, is spatio-temporally expressed only by activated microglial cells located within CA1 region following transient forebrain ischemia in gerbils. Furthermore, expression of galectin-3 and Iba-1 (a specific microglial cell marker) are strongly reduced by hypothermia during ischemic insult. To further elucidate the effect of hyperthermia on the expression of galectin-3 by micloglia in delayed neuronal death, we examined immunohistochemical expression of galectin-3 and Iba-1, in situ terminal dUTP-biotin nick end labeling of DNA fragmentation (for determination of cell death) and hematoxylin and eosin staining (for morphological observation). We observed that between 37 °C and 39 °C, there was a temperature-dependent enhancement of galectin-3 expression in microglial cells in the CA1 region following transient ischemia. Apoptotic DNA fragmentation, detected by TUNEL staining, was observed in CA1 region in normothermia. This TUNEL staining was enhanced by hyperthermia at 37.5 °C and 38 °C, but not at 39 °C. Ischemia-induced neuronal degeneration in CA1 region in gerbil hippocampus subjected to hyperthermia (37.5 °C, 38 °C and 39 °C) observed by HE staining is similar to that in normothermic gerbils. These findings imply that galectin-3 expression in microglia may influence the survival of CA1 pyramidal neurons in cases such as hyperthermia-related neuronal injury.

Galectin-3 expression in delayed neuronal death of hippocampal CA1 following transient forebrain ischemia, and its inhibition by hypothermia.

The ischemic damage in the hippocampal CA1 sector following transient ischemia, delayed neuronal death, is a typical apoptosis, but the mechanism underlying the delayed neuronal death is still far from fully understood. Galectin-3 is a ß-galactosidase-binding lectin which is important in cell proliferation and apoptotic regulation. Galectin-3 is expressed by microglial cells in experimental models of adult stroke. It has been reported that activated microglial cells are widely observed in the brain, including in the hippocampal CA1 region after transient ischemic insult. In the present study, time course expression of galectin-3 following transient forebrain ischemia in gerbils was examined by immunohistochemistry, combined with Iba-1 immunostaining (a specific microglial cell marker), hematoxylin and eosin staining (for morphological observation), and in situ terminal dUTP-biotin nick end labeling of DNA fragments method (for determination of cell death). Following transient ischemia, we observed a transient increase of galectin-3 expression in CA1 region, which was maximal 96h after reperfusion. Galectin-3 expression was predominately localized within CA1 region and observed only in cells which expressed Iba-1. The galectin-3-positive microglial cells emerge after the onset of neuronal cell damage. Expressions of galectin-3 and Iba-1 were strongly reduced by hypothermia during ischemic insult. Prevention of galectin-3 and Iba-1 expression in microglia by hypothermia has led us to propose that hypothermia either inhibits microglial activation or prevents delayed neuronal death itself. Our results indicate that galectin-3 might exert its effect by modulating the neuronal damage in delayed neuronal death.