[Effects of HMGB1 on Proliferation and Secretion of Human Bone Marrow Mesenchymal Stem Cells].

OBJECTIVE: To investigate the effect of high mobility group protein 1(HMGB1) on the proliferation and cytokine expression of human bone marrow mesenchymal stem cells (MSC). METHODS: Different concentrations of recombinant human HMGB1 protein (100, 200, 400, 800 and 1000 ng/ml) were incubated with MSC for 24, 48, 72 h and the proliferation of MSC were detected respectively by using the CCK-8 method and flow cytometry. The best concentrations of HMGB1 incubated with MSC was determined (200 ng/ml, 1000 ng/ml), and the flow cytomerty was used to determine the effect of HMGB1 on the proliferation of MSC. The mRNA expression levels of IL-10, TGF- ß1, TSG-6 and IFN-γ in MSC incubated with HMGB1 protein were detected by real-time quantitative PCR and ELISA. RESULTS: The result of MSC identification and flow cytometry showed that the CD105, CD73 and CD90 were expressed, but did not expression CD45, CD34, CD11b, CD19 and HLA-DR; CCK-8 showed that HMGB1 at the concentrations of 100 ng/ml, 200 ng/ml and 400 ng/ml could promote the proliferation of MSC incubated for 24, 48 and 72 h as compared with the control group (P<0.05), and the most effective concentration was 200 ng/ml; flow cytometry showed that the compared with the control group, HMGB1 200 ng/ml could induce MSC from G1 phase to S phase to promote the proliferation of MSC; QPCR showed that the mRNA expression of MSC cytokines IL-10, TGF-ß1, TSG-6 increased while IFN-γ decreased at the concentration of 200 ng/ml HMGB1 as compared with the control group. ELISA experiments showed that the HMGB1 200 ng/ml acting on MSC for 48 h could significantly promoted the secretion of IL-10, TGF-ß 1 and TSG-6(P<0．05), while IFN-γ showed no significant difference as compared with control group. CONCLUSION: Recombinant human HMGB1 can promote the proliferation and secretion of MSC in healthy people.

[Expression of HMGB1 in Spleen of Adult Patients with Chronic and Refractory Immune Thrombocytopenia and Its Significance].

OBJECTIVE: To investigate the expression and clinical significance of high mobility group box 1(HMGB1) in spleen of adult patients with chronic and refractory immune thrombocytopenia(ITP). METHODS: Twenty chronic and refactory ITP patients received splenectomy were enrolled in ITP group and 20 cases of traumatic spleen rupture were enrolled in control group. The splenectomy efficacy in ITP patients was analyzed retrospectively. The HMGB1 expression in spleen tissue was detected by immunohistochemistry, and the correlation between different expression levels of HMGB1 and splenectomy efficacy were analysed. Meanwhile, the protein expression levels of HMGB1 in peripheral blood serum and mononuclear cells(PBMNC) of 25 patients with chronic and refractory ITP were detected by ELISA and Western blot. RESULTS: The median platelet count before splenectomy was 7.5 (0-20) ×109/L; all the patients showed that the initial response to splenectomy within the first month after operation was 100%, the median time of response was 1 day (1-6 days). The median peak platelet count post splenectomy was 448.5 (161-1272)×109/L. In the median time of 10(3-30) months, the platelets count in 8 patients was reduced to varying degrees. After a median follow-up of 69.5 months (22-195), complete response was found in 12 patients, 4 cases showed response and 4 did not. The HMGB1 expression positive rate in spleen of ITP patients was significantly higher than that in control group (85.0% vs 15.0%)(P<0.001). There were a negative correlation between the HMGB1 expression in ITP and therapeutic outcome after splenectomy (r=-0.791, P<0.01). In addition, HMGB1 expression levels in serum and PBMNC of the patients with chronic refractory ITP were also significantly higher than that in healthy controls (P<0.01). CONCLUSION: The splenectomy has been found to be effective therapeutic method for patients with ITP, the HMGB1 highly express in the spleen of the patients with chronic refractory ITP, but negatively correlats with the therapeutic outcome after splenectomy.

[Role of Treg Cells in Pathogensis of Mouse ITP].

OBJECTIVE: To explore the role of Treg cells in the pathogenesis of idiopathic thrombocytopenic purpura (ITP). METHODS: The ITP mouse model was established, the Treg cell ratio in peripheral blood and spleen was detected by flow cytometry, the CD4+ CD25+ T cells were sorted by immunomagnetic beads, the Treg cell associated transcription factors (Foxp3, Smad7, STAT5 and Akt-1) and cytokines (IL-10, TGF-ß) in CD4+ CD25+ T cells were enriched from spleen mononuclear cells, and the mRNA expression of Treg cell was measured by real-time PCR. RESULTS: The ratio of Tregs in peripheral blood and spleen decreased significantly in ITP mouse, as compared with the controls (P<0.01). In addition, the mRNA expression of IL-10, TGF-ß and Foxp3 decreased significantly in spleen CD4+ CD25+ T cells (P<0.05). Expression of Smad 7 mRNA was higher than that of controls. CONCLUSION: The alteration in Treg frequency and function may be responsible for the immune dysfunction in ITP disease. It is also speculated that the lower mRNA expression of Foxp3 and higher mRNA expression of Smad 7 may inhibit the proliferation and differentiation of Treg cells.

Marked protection by selective cerebral profound hypothermia after complete cerebral ischemia in primates.

Hypothermia has been demonstrated to protect the brain from ischemia or traumatic brain injury. Achieving profound hypothermia has relied on techniques requiring total body cooling, which may result in serious cardiovascular and pulmonary complications. A technique to selectively cool the brain could conceivably exert a marked protection on cerebral structures and provide a relatively bloodless operative surgical field without systemic complications. Accordingly, this approach was tried in 7 rhesus monkeys after induction of general anesthesia. The right internal carotid artery and both internal jugular veins were each occlusively cannulated and connected to a circulation pump. The left internal carotid artery, both external carotid arteries, and both external jugular veins were temporarily clamped to establish severe cerebral ischemia. Using a closed-circuit system, cooled Ringer's lactate liquid (4 degrees C) was infused through right internal carotid artery with outflow draining though both internal jugular veins. Cooled perfusate decreased cerebral temperature to the target temperature of 15 degrees C. Thereafter, pump flow was discontinued, and brains were rewarmed spontaneously, while the temporarily clamped carotid arteries and jugular veins were opened to resume normal cerebral blood circulation. Neurological functions were recorded daily and cerebral histology was examined at the conclusion of the experiment. Magnetic resonance (MR) scans were routinely taken before and 3 weeks after ischemia. In the normothermia control group of five rhesus monkeys, Ringer's solution at 37 degrees C was infused in the same manner as the cold solution with cerebral temperature maintained at 36.7 +/- 0.32 degrees C. Right cerebral temperature decreased from 36.5 +/- 0.49 to 15.5 +/- 2.29 degrees C, and simultaneously the left cerebral temperature decreased from 36.4 +/- 0.38 to 16.3 +/- 2.4 degrees C for 62.8 +/- 9.76 min during selective cerebral cooled Ringer's liquid perfusion. In contrast, rectal temperature was only reduced to 32.4 +/- 0.96 degrees C from a baseline of 37.2 +/- 0.76 degrees C. Internal jugular vein hematocrit was 38.2 +/- 0.31% before perfusion and 2.82 +/- 0.46% at the end of perfusion in profound hypothermia group; hematocrit was 39.7 +/- 0.62% before perfusion and 3.42 +/- 0.38% at the end of perfusion in the normothermia group. In the hypothermic group, neurological functions were normal during 6 months of follow-up, and microscopic examination of brain tissue did not show evidence of pathological changes in hippocampus or medulla. MR scans did not show any cerebral infarction. In contrast, none of the monkeys in normothermia group survived for more than several hours, and microscopic examination of the brain revealed extensive neuronal necrosis within the medulla. Selective cerebral profound hypothermia provides significant histologic and neurologic protection after severe cerebral ischemia. In addition, there were no major complications, and the operative field remained relatively bloodless in the profound hypothermic group.