[Effects of altitude on circulating endothelial progenitor cells and hypoxia-inducible factor-1α in patients with type 2 diabetes]

Objective: To compare the changes in the number of circulating endothelial progenitor cells and hypoxia-inducible factors in patients with type 2 diabetes at different altitudes, and to provide a basis for the research and treatment of type 2 diabetes vascular complications. Methods: Selected Type 2 diabetes patients who were diagnosed in a low altitude area of 386 m (Xianyang City) and a high altitude area of 1 520 m (Lanzhou) (25 persons/29 persons) and healthy persons (20 persons/20 persons) were selected. An automatic biochemical analyzer was used to detect the indexes of blood lipids, blood glucose, and glycosylated hemoglobin of the two groups of people, and the concentration of Hypoxia inducible factor-1α (HIF-1α) was detected by enzyme-linked immunosorbent assay (ELISA). The number of circulating endothelial progenitor cells (EPCs) in peripheral blood was determined by a cytometer. Results: No matter in low or high altitude areas, the number of circulating EPCs in the diabetes group was lower than that in the healthy group (P＜0.01). The levels of body mass index (BMI), waist to hip ratio (WHR), triglyceride (TG), fasting blood glucose (FBG) and glycosylated hemoglobin (HbAlc) were increased (P＜0.05). Compared with the low-altitude group, the expression levels of HIF-1α in diabetic patients at high-altitude and healthy people were increased significantly (P＜0.05), while the number of circulating EPCs was decreased significantly (P＜0.05), and the number of circulating EPCs in healthy people or the patients with type 2 diabetes without vascular complications was higher than that of patients with type 2 diabetes with vascular complications (P＜0.05). Conclusion: With the increase in altitude, the expression level of HIF-1α in type 2 diabetes mellitus(T2DM)patients is increased, and the number of circulating EPCs is decreased, which is closely related to the degree of vascular disease. Therefore, it is possible through transplantation of EPCs for high altitude T2DM patients to achieve the prevention and improvement of diabetic vascular complications.

Protective effect of rhodioloside and bone marrow mesenchymal stem cells infected with HIF-1-expressing adenovirus on acute spinal cord injury

Rhodioloside has been shown to protect cells from hypoxia injury, and bone marrow mesenchymal stem cells have a good effect on tissue repair. To study the effects of rhodioloside and bone marrow mesenchymal stem cells on spinal cord injury, a rat model of spinal cord injury was established using the Infinite Horizons method. After establishing the model, the rats were randomly divided into five groups. Rats in the control group were intragastrically injected with phosphate buffered saline (PBS) (5 μL). PBS was injected at 6 equidistant points around 5 mm from the injury site and at a depth of 5 mm. Rats in the rhodioloside group were intragastrically injected with rhodioloside (5 g/kg) and intramuscularly injected with PBS. Rats in the mesenchymal stem cell (MSC) group were intramuscularly injected with PBS and intramuscularly with MSCs (8 × 10⁶/mL in a 50-μL cell suspension). Rats in the Ad-HIF-MSC group were intragastrically injected with PBS and intramuscularly injected with HIF-1 adenovirus-infected MSCs. Rats in the rhodioloside + Ad-HIF-MSC group were intramuscularly injected with MSCs infected with the HIF-1 adenovirus and intragastrically injected with rhodioloside. One week after treatment, exercise recovery was evaluated with a modified combined behavioral score scale. Hematoxylin-eosin staining and Pischingert’s methylene blue staining were used to detect any histological or pathological changes in spinal cord tissue. Levels of adenovirus IX and Sry mRNA were detected by real-time quantitative polymerase chain reaction and used to determine the number of adenovirus and mesenchymal stem cells that were transfected into the spinal cord. Immunohistochemical staining was applied to detect HIF-1 protein levels in the spinal cord. The results showed that: (1) compared with the other groups, the rhodioloside + Ad-HIF-MSC group exhibited the highest combined behavioral score (P < 0.05), the most recovered tissue, and the greatest number of neurons, as indicated by Pischingert’s methylene blue staining. (2) Compared with the PBS group, HIF-1 protein expression was greater in the rhodioloside group (P < 0.05). (3) Compared with the Ad-HIF-MSC group, Sry mRNA levels were higher in the rhodioloside + Ad-HIF-MSC group (P < 0.05). These results confirm that rhodioloside combined with bone marrow mesenchymal stem cells can promote the recovery of spinal cord injury and activate the HIF-1 pathway to promote the survival of bone marrow mesenchymal stem cells and repair damaged neurons within spinal cord tissue. This experiment was approved by the Animal Ethics Committee of Gansu University of Traditional Chinese Medicine, China (approval No. 2015KYLL029) in June 2015.

Exosomal miRNAs as Biomarkers of Cancer: a Meta-Analysis

BACKGROUND

Tumor-derived exosomal miRNAs secreted by cancer cells play significant roles in the pathological processes of cancer, but no systematic meta-analysis has focused on the diagnostic efficiency of exosomal miRNAs. This meta-analysis assessed the diagnostic value of circulating exosomal miRNA in cancer.

METHODS

Studies evaluating the diagnostic value of exosomal miRNA were identified in EMBASE, PubMed, Cochrane Library, and Web of Science up to August 1, 2018. The quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies 2, and STATA 14.0 was used for the analyses. The true positive (TP), false positive (FP), true negative (TN), and false negative (FN) rates were extracted from each study to obtain the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and their 95% confidence intervals (CIs).

RESULTS

The meta-analysis included 16 studies with 1,591 patients. Five studies reported sensitivity values, and the pooled sensitivity was 0.86 (95% CI = 0.80 - 0.90, while 29 studies reported specificity values, and the pooled specificity was 0.89 (95% CI = 0.83 - 0.93). The pooled PLR was 7.8 (95% CI = 4.9 - 12.4), the pooled NLR was 0.16 (95% CI = 0.11 - 0.24), the pooled DOR was 48 (95% CI = 23 - 101), and the AUC was 0.94 (0.91 - 0.96).

CONCLUSIONS

Our meta-analysis indicated that body fluid exosomal miRNAs are highly accurate for distinguishing patients from healthy individuals, and exosomal miRNAs have superior diagnostic value in plasma, prostate cancer patients, and non-Asian individuals.

A meta-analysis of the effects of probiotics and synbiotics in children with acute diarrhea

OBJECTIVE

This meta-analysis assessed the effectiveness of probiotics and synbiotics for acute diarrhea (AD) in children and investigated probiotic formulations, types of interventions, and country factors.

METHODS

Randomized, double-blind, placebo-controlled trials evaluating the effects of probiotics or synbiotics on AD were analyzed. We followed the recommendations of the Cochrane Handbook and the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The risks of systematic errors (bias) and random errors were assessed, and the overall quality of the evidence was evaluated using the Grades of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

The meta-analysis included 34 studies with 4911 patients. Five and 29 studies presented the results of synbiotic and probiotic interventions, respectively. After intervention, the durations of diarrhea (weighted mean difference (WMD) = -16.63 [-20.16; -12.51]) and hospitalization (risk ratio (RR) = 0.59 [0.48; 0.73]) were shorter, the stool frequency on day 3 (WMD = -0.98 [-1.55; -0.40]) was decreased, and the incidence of diarrhea lasting 3 days was lower in the probiotic and synbiotic groups than in the control groups. Furthermore, in the subgroup analyses, synbiotics were more effective than probiotics at reducing the durations of diarrhea and hospitalization, and Saccharomyces and Bifidobacterium were more effective than Lactobacillus at reducing the duration of diarrhea.

CONCLUSION

This meta-analysis supports the potential beneficial roles of probiotics and synbiotics for AD in children. Further research is needed to determine problems associated with probiotic/synbiotic mixtures and appropriate dosages.

[Protective effects and mechanism of keratinocyte growth factor combined with hypoxia inducible factor-1α on intestinal crypt epithelial cells of rats with hypoxia stress]

Objective: To investigate the protective effects and mechanism of keratinocyte growth factor (KGF) combined with hypoxia inducible factor-1α (HIF-1α) on intestinal crypt epithelial cells (IEC-6) of rats with hypoxia stress. Methods: (1) The routinely cultured IEC-6 of rats were collected and divided into normoxia blank group, normoxia KGF group, normoxia HIF-1α group, and normoxia combine group, according to the random number table, and then the previous mediums were respectively replaced with dulbecco's modified eagle medium (DMEM), medium with 0.5 ng/mL KGF, medium with 10.0 ng/mL HIF-1α, and medium with 0.5 ng/mL KGF and 30.0 ng/mL HIF-1α. And the cells were cultured in cell incubator with oxygen volume fraction of 21% for 24 hours. (2) Another batch of routinely cultured IEC-6 were collected and divided into normoxia control group, hypoxia control group, hypoxia KGF group, hypoxia HIF-1α group, and hypoxia combine group, according to the random number table. The previous mediums were replaced with DMEM, DMEM, medium with 0.5 ng/mL KGF, medium with 10.0 ng/mL HIF-1α, and medium with 0.5 ng/mL KGF and 30.0 ng/mL HIF-1α respectively. And then, the cells in normoxia control group were cultured routinely for 24 hours, and cells in the other 4 groups were cultured in cells incubator of 3 gases, with oxygen volume fraction of 5% for 24 hours. Cells cultured in normoxic and hypoxic incubators were collected, with 3 samples in each group, and morphological changes of cells were observed with optical microscope. Cells cultured in normoxic and hypoxic incubators were collected, with 3 samples in each group, and survival rates of cells were detected by cell count kit 8. Cells in normoxia control group and cells cultured in hypoxic incubator were collected, with 3 samples in each group. The cell cycle changes and apoptosis rates were detected by flow cytometer, the content of adenosine triphosphate (ATP) was detected by ultraviolet spectrophotometer, and protein expression of p53 was detected by Western blotting. Data were processed with one-way analysis of variance and least significant difference test. Results: (1) After being cultured for 24 h, cells cultured in normoxic incubator grew well with oval or round shapes and clear cytoplasm, and cells cultured in hypoxic incubator showed irregular shapes such as fusiform or starlike shape, with black particle in cytoplasm. (2) After being cultured for 24 h, cell survival rates of normoxia blank group, normoxia KGF group, normoxia HIF-1α group, and normoxia combine group were (107.4±8.7)%, (109.8±2.9)%, (115.8±7.4)%, and (112.8±10.6)% respectively. There was no significantly statistical difference in general comparison of cell survival rates among the above groups (F=0.685, P=0.586). After being cultured for 24 h, cell survival rates of hypoxia control group, hypoxia KGF group, hypoxia HIF-1α group, and hypoxia combine group were (35.1±4.6)%, (52.9±6.8)%, (56.2±3.1)%, and (71.2±9.6)% respectively, which were significantly lower than (106.3±12.3)% of normoxia control group (P<0.001). Survival rates of cells in hypoxia KGF group, hypoxia HIF-1α group, and hypoxia combine group were significantly higher than the rate of cells in hypoxia control group (P=0.023, 0.009, <0.001). Survival rate of cells in hypoxia combine group was significantly higher than the rates of cells in hypoxia KGF group and hypoxia HIF-1α group (P=0.017, 0.045). (3) After being cultured for 24 h, percentage of cells in G1 phase in hypoxia control group was significantly higher than that of cells in normoxia control group (P=0.030), percentages of cells in S phase in hypoxia control group, hypoxia KGF group, and hypoxia HIF-1α group were obviously lower than the percentage of cells in normoxia control group (P=0.020, 0.031, 0.026), and percentages of cells in different phases in other groups were close to those of cells in normoxia control group (P=0.516, 0.107, 0.052, 0.985, 0.637, 0.465, 0.314, 0.591). After being cultured for 24 h, percentages of cells in G1 phase in hypoxia control group, hypoxia KGF group, and hypoxia HIF-1α group were obviously higher than the percentage of cells in hypoxia combine group (P=0.001, 0.030, 0.014), and percentages of cells in S phase in the above 3 groups were obviously lower than the percentage of cells in hypoxia combine group (P=0.001, 0.012, 0.010). (4) After being cultured for 24 h, compared with that of cells in normoxia control group, apoptosis rate of cells in hypoxia control group obviously increased (P=0.018), and apoptosis rate of cells in hypoxia combine group obviously decreased (P=0.008). After being cultured for 24 h, compared with that of cells in hypoxia control group, apoptosis rates of cells in hypoxia KGF group and hypoxia combine group obviously decreased (P=0.004, 0.001). Apoptosis rate of cells in hypoxia combine group was obviously lower than those of cells in hypoxia KGF group and hypoxia HIF-1α group (P=0.032, 0.002). (5) After being cultured for 24 h, compared with that of cells in normoxia control group, the content of ATP of cells in hypoxia combine group changed unobviously (P=0.209), and content of ATP of cells in the other groups obviously decreased (P= <0.001, 0.001, 0.002). Content of ATP of cells in hypoxia HIF-1α group and hypoxia combine group was obviously higher than that of cells in hypoxia control group (P=0.044, 0.001). Content of ATP of cells in hypoxia combine group was obviously higher than that of cells in hypoxia KGF group and hypoxia HIF-1α group (P=0.011, 0.020). (6) After being cultured for 24 h, protein expressions of p53 of cells in hypoxia control group, hypoxia KGF group, and hypoxia HIF-1α group were obviously higher than that of cells in normoxia control group (P<0.001), and protein expression of p53 of cells in hypoxia combine group was obviously lower than those of cells in hypoxia control group, hypoxia KGF group, and hypoxia HIF-1α group (P=0.001, 0.001, 0.002). Conclusions: KGF combined with HIF-1α have significant protective effects on IEC-6 of rats with hypoxia stress, and can improve its survival in hypoxic environment by inhibiting cell cycle arrest, reducing the level of apoptosis, and increasing level of energy metabolism.

Endothelial progenitor cells in peripheral blood may serve as a biological marker to predict severe acute pancreatitis

AIM

To investigate the significance of endothelial progenitor cells (EPCs) in predicting severe acute pancreatitis (SAP).

METHODS

We recruited 71 patients with acute pancreatitis (AP) and excluded 11 of them; finally, cases of mild acute pancreatitis (MAP) (n = 30) and SAP (n = 30), and healthy volunteers (n = 20) were internalized to investigate levels of EPCs, C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), fibrinogen (FIB) and white blood cells (WBC) in peripheral blood.

RESULTS

The levels of TNF-α, WBC, FIB and CRP were higher both in SAP and MAP cases than in healthy volunteers (P < 0.05, all). Interestingly, the level of EPCs was higher in SAP than MAP (1.63% ± 1.47% vs 6.61% ± 4.28%, P < 0.01), but there was no significant difference between the MAP cases and healthy volunteers (1.63% ± 1.47% vs 0.55% ± 0.54%, P > 0.05). Receiver operating characteristics curve (ROC) showed that EPCs, TNF-α, CRP and FIB were significantly associated with SAP, especially EPCs and CRP were optimal predictive markers of SAP. When the cut-off point for EPCs and CRP were 2.26% and 5.94 mg/dL, the sensitivities were 90.0% and 73.3%, and the specificities were 83.3% and 96.7%. Although, CRP had the highest specificity, and EPCs had the highest sensitivity and highest area under the curve value (0.93).

CONCLUSION

Data suggest that EPCs may be a new biological marker in predicting SAP.

Cytokine gene therapy for treatment of ischemia and hypoxia stress induced gastrointestinal injury

Stress induced gastrointestinal ischemia and hypoxia injury is a common digestive system condition caused via complicated mechanisms. Although clinical treatments are diverse, their efficacy is still not satisfactory. Recently, many cytokines have been shown to be related to gastrointestinal ischemia and anoxia, such as hepatocyte growth factor, hypoxia inducible factor, and keratinocyte growth factor. The number of studies on cytokines for the treatment of gastrointestinal diseases is increasing. We have constructed a eukaryotic expression vector carrying cytokine genes to transfer cytokine genes to the local damage tissue to achieve the therapeutic purpose. Cytokine gene therapy may be a safe and effective new strategy for repairing gastrointestinal ischemia and hypoxia stress injury, which will offer a new tool for the mechanism research and treatment of hypoxic ischemic disease.

Salidroside induces neuronal differentiation of mouse mesenchymal stem cells through Notch and BMP signaling pathways

Salidroside (p-hydroxyphenethyl-β-D-glucoside, SAL), a phenylpropanoid glycoside isolated from a popular traditional Chinese medicinal plant Rhodiola rosea L., possesses multiple pharmacological actions. Previous study showed that SAL could induce rat mesenchymal stem cells (MSCs) to differentiate into dopaminergic neurons and induce mouse MSCs D1 to differentiate into neuronal cells. However, the mechanisms of SAL-induced neuronal differentiation of MSCs still need investigation. In this study, we observed the effects of SAL on neuronal differentiation of D1 cells and the possible involvement of Notch and BMP signaling pathways. SAL inhibited the proliferation, induced neuronal phenotypes, and upregulated the expressions of neuronal-specific marker molecules, such as neuronal enolase 2 (Eno2/NSE), microtubule-associated protein 2 (MAP2), and beta 3 class III tubulin (Tubb3/β-tubulin III) in D1 cells. SAL not only downregulated the expressions of Notch1 and hairy enhancer of split 1 (Drosophila) (Hes1) but also upregulated the expression of Smad1/5/8 and its phosphorylation (p-Smad 1/5/8). The neuronal differentiation effects of SAL on D1 cells were promoted by a Notch signaling antagonist, DAPT, but attenuated by a BMP signaling pathway antagonist, Noggin. Our findings suggest that SAL might be promising in inducing neuronal differentiation of mouse MSCs mediated by both Notch signaling pathway and BMP signaling pathway.

Distribution of endothelial progenitor cells in tissues from patients with gastric cancer

It is accepted that endothelial progenitor cells (EPCs) are recruited into tumor sites and take part in the neovascularization of tumors. However, few articles have discussed the specific distribution of EPCs in vivo in tissues of gastric cancer patients. For this reason, the present study sought to elucidate EPC distribution in vivo in tissues of patients with gastric cancer. Fresh tumor tissues were collected from 26 newly diagnosed patients with histologically confirmed gastric cancer (mean age, 51 years; range, 21–81 years; 7 females, 19 males). All patients were treated surgically with curative intent. One portion of the fresh tissues was prepared for flow cytometric analysis and another was immediately snap frozen in liquid nitrogen and stored at −80°C for later use in quantitative polymerase chain reaction. The analysis was based on two groups of tissues, namely the cancer group and cancer-adjacent group. The presence of CD34/CD133 double-positive cells was determined in cancer-adjacent and cancer tissues by flow cytometry. The analysis revealed that the total number of EPCs in cancer tissue was slightly greater than the number in the cancer-adjacent tissue, but not to the point of statistical significance. The number of EPCs in cancer-adjacent and cancer tissues of patients with early-stage gastric cancer was higher than the EPC count in late-stage gastric cancer patients, and significant differences were identified in the number of EPCs in cancer tissue between patients of different tumor stages. Levels of cluster of differentiation (CD)34, CD133 and vascular endothelial growth factor receptor 2 were not significantly different in cancer-adjacent tissue compared with cancer tissue. These results suggest that cancer-adjacent and cancer tissue of gastric cancer patients may be used as a reference index in the clinical and pathological staging of tumors.

Salidroside induces rat mesenchymal stem cells to differentiate into dopaminergic neurons

Parkinson’s disease (PD) is a neurodegenerative disorder characterised by the loss of substantia nigra dopaminergic neurons that leads to a reduction in striatal dopamine (DA) levels. Replacing lost cells by transplanting dopaminergic neurons has potential value to repair the damaged brain. Salidroside (SD), a phenylpropanoid glycoside isolated from plant Rhodiola rosea, is neuroprotective. We examined whether salidroside can induce mesenchymal stem cells (MSCs) to differentiate into neuron-like cells, and convert MSCs into dopamine neurons that can be applied in clinical use. Salidroside induced rMSCs to adopt a neuronal morphology, upregulated the expression of neuronal marker molecules, such as gamma neuronal enolase 2 (Eno2/NSE), microtubule-associated protein 2 (Map2), and beta 3 class III tubulin (Tubb3/β-tubulin III). It also increased expression of brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and nerve growth factor (NGF) mRNAs, and promoted the secretion of these growth factors. The expression of dopamine neurons markers, such as dopamine-beta-hydroxy (DBH), dopa decarboxylase (DDC) and tyrosine hydroxylase (TH), was significantly upregulated after treatment with salidroside for 1–12 days. DA steadily increased after treatment with salidroside for 1–6 days. Thus salidroside can induce rMSCs to differentiate into dopaminergic neurons.

Overall codon usage pattern of enterovirus 71

Hand, foot, and mouth disease (HFMD) is a systemic illness in children and is usually caused by enterovirus 71 (EV71). To provide new insights into the genetic features of EV71 and the relationship between the overall codon usage pattern of this virus and that of humans, values for relative synonymous codon usage (RSCU), effective number of codons (ENC), codon adaptation index (CAI), and nucleotide composition were calculated and analyzed. The relationship between ENC values and (G+C)₃% suggests that, although nucleotide composition plays an important role in shaping the overall codon usage pattern of this virus, other factors also affect this pattern. In addition, the negative correlation between the CAI value and (G+C)₃% suggests that the secondary structure of the EV71 coding sequence caused by its nucleotide composition can affect gene expression. Moreover, there was no significant correlation between ENC and CAI, suggesting that gene expression does not play a role in shaping the overall codon usage pattern of EV71. The overall codon usage pattern of the EV71 virus is only partly similar to the general codon pattern of human, suggesting that, although EV71 has co-evolved with humans for extended periods, mutation pressure played an important role in shaping the virus's overall codon usage pattern. These results revealed that the EV71 virus has developed a subtle strategy during evolution for adapting to environmental changes in its host cells solely by means of mutation pressure.

[The toxic effects of lead acetate on the apoptosis and the ultrastructure in human renal tubular epithelial cells (HK-2)]

OBJECTIVE

To explore the toxic effects of lead acetate on the apoptosis and ultrastructure of human renal tubular epithelial cells (HK-2).

METHODS

After HK-2 cells were exposed to 5, 10 and 20 µmol/L lead acetate for 24 h, the morphological changes of HK-2 cells were observed by Hochest 33342-PI staining, and the ultrastructure changes of HK-2 cells were examined under a electron microscope, LDH activity and MDA content in supernatant of HK-2 cellular culture were detected by spectrophotometer, DNA damage of HK-2 was determined by DNA ladder and the apoptotic rates of HK-2 cells were measured by flow cytometry.

RESULTS

The morphological changes of apoptotic HK-2 cells in exposure group were observed by Hochest 33342-PI staining. The cytoplasm vacuoles, karyopycnosis, nuclear membrane vague and apoptotic bodies in HK-2 cells of exposure group were found under electron microscopy. LDH activity and MDA contents in exposure group increased significantly, as compared to control group (P < 0.01). The results of DNA Ladder showed that DNA damage of HK-2 cells in exposure group appeared. The apoptotic rates of HK-2 cells exposed to 5, 10, 20 µmol/L lead acetate were 14.16% ± 2.94%, 19.45% ± 2.73%, 25.01% ± 3.97%, respectively, which were significantly higher than that (5.81% ± 2.18%) in control group (P < 0.05).

CONCLUSION

Lead acetate could remarkably induce the apoptosis of HK-2 cells and affect the kidney.

Keratinocyte growth factor gene therapy ameliorates ulcerative colitis in rats

AIM: To investigate the effect of keratinocyte growth factor (KGF) gene therapy in acetic acid-induced ulcerative colitis in rat model.

METHODS: The colitis of Sprague-Dawley rats was induced by intrarectal infusion of 1 mL 5% (v/v) acetic acid. Twenty-four hours after exposed to acetic acid, rats were divided into three experimental groups: control group, attenuated Salmonella typhimurium Ty21a strain (SP) group and SP strain carrying human KGF gene (SPK) group, and they were separately administered orally with 10% NaHCO₃, SP or SPK. Animals were sacrificed and colonic tissues were harvested respectively on day 3, 5, 7 and 10 after administration. Weights of rats, colonic weight/length ratio and stool score were evaluated. Histological changes of colonic tissues were examined by hematoxylin and eosin (HE) staining method. The expression of KGF, KGF receptor (KGFR) and TNF-α were measured either by enzyme-linked immunosorbent assay or Western blotting. Immunohistochemistry was used to detect the cellular localization of KGFR and Ki67. In addition, superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in the homogenate were measured.

RESULTS: Body weight and colonic weight/length ratio were declined in SPK group compared with SP and control groups (body weight: 272.78 ± 17.92 g vs 243.72 ± 14.02 g and 240.68 ± 12.63 g, P < 0.01; colonic weight/length ratio: 115.76 ± 7.47 vs 150.32 ± 5.99 and 153.67 ± 5.50 mg/cm, P < 0.01). Moreover, pathological changes of damaged colon were improved in SPK group as well. After administration of SPK strain, KGF expression increased markedly from the 3rd d, and remained at a high level till the 10th d. Furthermore, KGFR expression and Ki67 expression elevated, whereas TNF-α expression was inhibited in SPK group. In the group administered with SPK, SOD activity increased significantly (d 5: 26.18 ± 5.84 vs 18.12 ± 3.30 and 18.79 ± 4.74 U/mg, P < 0.01; d 7: 35.48 ± 3.35 vs 22.57 ± 3.44 and 21.69 ± 3.94 U/mg, P < 0.01; d 10: 46.10 ± 6.23 vs 25.35 ± 4.76 and 27.82 ± 6.42 U/mg, P < 0.01) and MDA contents decreased accordingly (d 7: 7.40 ± 0.88 vs 9.81 ± 1.21 and 10.45 ± 1.40 nmol/mg, P < 0.01; d 10: 4.36 ± 0.62 vs 8.41 ± 0.92 and 8.71 ± 1.27 nmol/mg, P < 0.01), compared with SP and control groups.

CONCLUSION: KGF gene therapy mediated by attenuated Salmonella ameliorates ulcerative colitis induced by acetic acids, and it may be a safe and effective treatment for ulcerative colitis.

Keratinocyte growth factor (KGF) gene therapy mediated by an attenuated form of Salmonella typhimurium ameliorates radiation induced pulmonary injury in rats

The aim of this study is to investigate the effect of KGF (Keratinocyte growth factor) gene therapy mediated by the attenuated Salmonella typhimurium Ty21a on radiation-induced pulmonary injury in rats model. Sprague-Dawley rats were divided into three groups: TPK group (treated with TPK strain, attenuated Salmonella typhimurium Ty21a-recombined human KGF gene); TP group (treated with TP strain, attenuated Salmonella typhimurium Ty21a-recombined blank plasmid); and Saline group (treated with saline). After intraperitoneal administration for 48 h, the thoraxes of the rats were exposed to X-ray (20 Gy), and the rats were administered again two weeks after radiation. On the 3rd, 5th, 7th, 14th and 28th day after radiation, the rats were sacrificed and lung tissues were harvested. Histological analysis was performed, MDA contents and SOD activity were detected, mRNA levels of KGF, TGF-β, SP-A and SP-C were measured by Real-time RT-PCR, and their concentrations in the BALF were quantified with ELISA. Administration of TPK strain improved the pathological changes of the lung on the 28th day. In the TPK group, KGF effectively expressed since the 3rd day, MDA contents decreased and SOD activity increased significantly, on the 7th day and 14th day respectively. SP-A and SP-C expression elevated, whereas TGF-β expression was inhibited in the TPK group. These results suggest that this novel gene therapy of KGF could ameliorate radiation-induced pulmonary injury in rats, and may be a promising therapy for the treatment of radiative pulmonary injury.

Effects of hepatocyte growth factor-mediated activation of Dll4-Notch-Hey2 signaling pathway

BACKGROUND

Hepatocyte growth factor (HGF) treats ischemic disease by promoting arteriogenesis, however, its mechanism of action is not known. The notch signaling pathway plays an important role in neovascularization. The relationship between the proliferation and migration ability of artery endothelial cells and the Dll4-Notch-Hey2 signaling pathway in the process of arteriogenesis was investigated as a mechanism of action of HGF.

METHODS

Based on the prophase study cells and supernatant were harvested at the indicated time after human femoral artery endothelial cells (HFAECs) were infected with adenovirus-HGF (Ad-HGF) at 200 pfu/cell. Cells were analyzed for HGF expression and Notch1, Dll4 and Hey2 expression by ELISA and reverse transcription-PCR (RT-PCR). The changes in the proliferation and migration ability of HFAECs were observed by MTT and Transwell migration experiments. Ad-GFP-infected HFAECs were used as control.

RESULTS

Compared with the control group the Ad-HGF group's HGF expression was not increased with time, and the induction by HGF of Notch1, Dll4 and Hey2 gene transcription was not enhanced with an increase of HGF. The proliferation ability of Ad-HGF-transduced HFAECs was enhanced and their migration ability was also enhanced in the presence of HGF.

CONCLUSIONS

Through activating the Dll4-Notch-Hey2 signaling pathway, HGF indirectly promotes the proliferation and migration ability of cells, so that offspring artery branches are formed.

[Human papillomavirus 16E6 gene mutation in cervical carcinoma tissues]

BACKGROUND AND OBJECTIVE

Human papillomavirus (HPV) 16 is the most common type of high-risk human HPVs. HPV16 E6 gene and its specific mutations are considered as risk factors causing cervical carcinoma (CC). This study was to investigate HPV16 E6 mutations in Lanzhou region and explore the relationship between HPV16 E6 mutations and the development of CC.

METHODS

Tissue DNA was extracted from 23 patients operated on for CC and five normal cervical controls. The partial sequence of the HPV16 E6 gene (nucleotide 201-523) was amplified by PCR from the tissue DNA extracted from the samples. PCR fragments were sequenced and analyzed.

RESULTS

The positive rates of HPV16 E6 in five normal cervical and 23 CC tissues were 0 (0/5) and 82.61% (19/23), respectively. Prototype HPV16E6 gene was found in six cases (33.33%) while mutation in the E6 gene was detected in 12 cases (66.67%), among which a 350G mutation was found in 11 cases (61.11%). Moreover, a 249G mutation was identified in one CC case (5.56%).

CONCLUSIONS

There is a high HPV infection rate in CC tissues in Lanzhou region, and most of the HPV16E6 are mutated.

Detection of methylation status of Caveolin-2 gene in gastric carcinoma

AIM: To investigate the relationship between methylation of 5'CpG island in the promoter region of Caveolin-2 gene and development of gastric carcinoma.

METHODS: Using methylation-specific PCR technique, the methylation status of the 5'CpG island in the promoter region of Caveolin-2 gene was measured in 33 tissue samples of gastric carcinoma and 5 normal gastric tissue samples >5 cm apart from tumor.

RESULTS: Methylation of the 5'CpG island in the promoter region of Caveolin-2 gene in all 5 samples of normal gastric tissues was negative. In 33 gastric cancerous tissue samples, the methylation positive rate of promoter region of Caveolin-2 gene was 87.9% (29/33), among which 20 cases (60.6%) complete methylation, 9 cases (27.3%) were partial methylation, and 4 samples were negative. Statistics showed the methylation rate of the promoter region of Caveolin-2 gene was obviously higher in gastric carcinoma than in normal gastric tissues.

CONCLUSION: The methylation positive rate of the 5'CpG island in the promoter region of Caveolin-2 gene in gastric carcinoma is high, indicating that its methylation may be related to genesis of gastric carcinoma.

[Prokaryotic expression, polyclonal antibody preparation and subcellular localization of CIB]

AIM

To construct the prokaryotic expression vector pET32a-CIB, prepare the specific polyclonal antibody against CIB and study the subcellular localization of CIB.

METHODS

CIB was amplified by RT-PCR from human brain tissue and cloned into prokaryotic expression vector pET32a-CIB. The CIB fusion protein was expressed in BL21 (DE3)/pET system and identified by SDS-PAGE. The mice were immunized with the polyacrylamide gel particles containing the CIB fusion protein for polyclonal antibody preparation. The antibody was purified by affinity chromatographic column matrix coupled with protein G, antigen respectively and then identified by Western blot and immunohistochemistry.

RESULTS

The protein of CIB was obtained by recombination expression. The specificity of polyclonal antibody was obtained by immunizing BALB/c mice with polyacrylamide gel particles containing the fusion protein of CIB and purification. The results of immunohistochemistry demonstrated that CIB was localized predominantly in the cytoplasm of SHG44 and Hhu7 cells.

CONCLUSION

The protein of CIB has been cloned and expressed successfully. The specific polyclonal antibody against the protein of CIB has been obtained, which can be used for further research into the function of CIB.

Distribution of attenuated salmonellae carrying hepatocyte growth factor genes in murine gastric ulcers

AIM: To highlight tissue distribution of attenuated salmonellae carrying hepatocyte growth factor (HGF) genes in murine gastric ulcers and thereby to provide a basis for HGF application in gene therapy for gastric ulcers.

METHODS: Eighty acetic acid-induced gastric ulcer rats were randomly divided into two groups: HGF treatment group (n = 40 rats) and green fluorescent protein (GFP) treatment group (n = 40 rats). Intragastric administration of attenuated salmonellae carrying HGF and GFP was performed on rats, each one with 0.2 mL, and once every two days for totally 3 times. Three rats in GFP group were killed each time on day 1, 3, 5, 7, 9 and frozen sections were made from stomach, liver, intestines, spleen and kidney to observe tissue distribution of target genes under fluorescence microscopy; 3 rats in HCF group were killed each time on day 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 and 21 to obverse tissue expression using ELISA and to detect tissue distribution of eukaryotic expression vector using PCR.

RESULTS: In GFP group, some strong fluorescence was observed in the stomach and intestines under fluorescence microscopy, and weak fluorescence in liver, spleen and kidneys. The intensity of fluorescence reached its peak on day 5 and day 7. In HGF group, high-level HGF gene expression by ELISA was detected in stomach, liver, spleen, kidney and intestines with higher expression in the intestines and stomach. CMV promoter fragment of eukaryotic expression vectors was detected in stomach, liver, spleen, kidney, large intestine and small intestine.

CONCLUSION: As a cellular vector, orally-administrated attenuated salmonellae could transfer target genes eukaryotic expression vector into stomach and intestinal tissues for gastric ulcer treatment in rats.

Gene therapy of hepatocyte growth factor mediated by attenuated salmonella typhimurium for TNBS-induced ulcerative colitis in rats

AIM: To explore the therapeutic efficacy of attenuated salmonella typhimurium carrying human hepatocyte growth factor (Typl-HGF) gene in rats with ulcerative colitis (UC) induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS).

METHODS: Forty ulcerative colitis model rats were induced by TNBS enema, and then randomly divided into 4 groups (n = 10): simple attenuated salmonella typhimurium (Ty) control group, Typl-HGF group, attenuated salmonella typhimurium carrying green fluorescent protein (Typl-GFP) gene group and model control group. Another 10 rats were intrarectally administered with normal saline, serving as normal control group. After 3-6 times of treatment, the colons were removed and scored by appearance, and then the specimens were subjected to HE staining for histological observation and scoring. The expression of target gene in colon tissues was observed under fluorescence microscope.

RESULTS: The weights of rats treated 3 times with Typl-HGF had a little increase, but those of rats treated 6 times with Typl-HGF showed a significant increase (9.75 ± 2.07 g) (P < 0.05). The common symptoms of colitis were not obviously ameliorated in Ty group and model control group. Grossly, mucosal hyperemia and thickening of colonic wall were evidently ameliorated, and the colon appearance scores of rats treated with Typl-HGF 3 or 6 times were significantly lower than those of rats in Ty group and model control group (2.20 ± 0.90 vs 5.10 ± 1.70, 5.30 ± 1.30; 1.70 ± 1.10 vs 4.00 ± 1.50, 4.30 ± 1.20; all P < 0.01); there was a significant difference between rats treated with Typl-HGF 3 and 6 times (P < 0.05). Histopathologically, in Typl-HGF-treated 3-time group, the score was not significantly different from that in Ty group or model control group, but the score in Typl-HGF-treated 6-time group was significantly higher than that in model control group (1.60 ± 0.30 vs 3.50 ± 0.70, P < 0.05). GFP expression was observed in colon tissues after intragastric administration of Typl-GFP.

CONCLUSION: Typl-HGF can dramatically ameliorate mucosal inflammation and symptoms of TNBS-induced colitis as well as promote the repair of mucosal damage and ulcer in rats.

[Plasmid pUDKH gene therapy of rat acute hindlimb ischemia: an experimental study]

OBJECTIVE

To investigate the effect of plasmid pUDKH carrying human hepatocyte growth factor (HGF) gene on rat acute limb ischemia and to find the lowest effective dosage.

METHODS

Ligation of femoral artery of one hindlimb in Wistar rats was performed. The rats were randomly divided into 5 groups of 10 rats: pUDKH 50 microg, 100 microg, 200 microg, and 400 microg groups and a vacant vector pUDK group (control group). The plasmids were injected once directly into the ischemic limb muscle (5 sites around ligation position) immediately after ligation. At day 10, the muscles were removed and stained with H.E. to assess histologically the blood vessel formation. HGF expression was detected in the muscle tissue of another 12 rats on days 3, 5, 10, 14, 21, 30 after injection of pUDKH or pUDK, 200 microg each per animal.

RESULTS

HGF expression was detected clearly in muscle tissue on days 3, 5, 10, 14 in pUDKH groups. In HGF-transfected animals (except for 50 microg group) neoformation of blood vessels in muscles and soft tissues was found, while it was not seen in controls. By semi-quantitation of the degree of vessel formation, significant differences between pUDKH groups (0.96 +/- 0.07, 1.97 +/- 0.91, 2.26 +/- 1.00 for 100 microg, 200 microg, 400 microg, respectively) and the control group (0.27 +/- 0.04) (P < 0.05) were noted. In addition, injection of pUDKH could alleviate the severity of degeneration of muscular tissue due to ischemia.

CONCLUSION

Human HGF gene therapy is effective in treating rat acute limb ischemia with the lowest effective dose of 100 microg.

Treatment of myocardial ischemia with bone marrow-derived mesenchymal stem cells overexpressing hepatocyte growth factor

Mesenchymal stem cells could differentiate into cardiomyocytes in vitro and have been shown to reconstitute the impaired myocardium in vivo. Hepatocyte growth factor, a recognized angiogenic factor and endothelial cell chemoattractant, has been applied in the treatment of myocardial ischemia. In this study, we used a ligation model of proximal left anterior descending coronary artery of rats to evaluate the effect of mesenchymal stem cells overexpressing hepatocyte growth factor in the treatment of myocardial ischemia. Bone marrow-derived mesenchymal stem cells were isolated, expanded, characterized, and infected with adenovirus carrying human hepatocyte growth factor cDNA (Ad-HGF). Mesenchymal stem cells infected by Ad-HGF released soluble HGF protein at a high level, which was maintained at least for 2 weeks. Implantation of mesenchymal stem cells overexpressing hepatocyte growth factor into left anterior descending risk areas improved the functions of impaired myocardium, including diminishing the area of ischemia, increasing the number of capillaries, and reducing collagen content. By using the sry gene as a marker, we also demonstrated that the engrafted cells or their progeny incorporated into ischemic cardiac muscle. These results showed that treatment of myocardial ischemia with bone marrow-derived mesenchymal stem cells overexpressing hepatocyte growth factor could be a novel strategy that can both restore local blood flow and regenerate lost cardiomyocytes.

[Study on construction of a plasmid vector carrying human hepatocyte growth factor gene and activity of its expression product]

AIM

To construct a plasmid carrying hepatocyte growth factor gene and investigate its effects in vitro.

METHODS

A complementary DNA (cDNA) clone for human HGF was isolated from human placental cDNA, then subcloned into pUDK vector, which was constructed by ourselves, to form the pUDKH plasmid. The transfection efficiency and the expression level of HGF and VEGF were evaluated by transfecting pUDK or pUDKH into primary rat skeletal muscle cells. The biological effects of HGF-expressing product at different doses on endothelial cells were investigated in vitro, and assessed by MTT.

RESULTS

The primary rat skeletal muscle cells could be transfected efficiently with pUDKH (0.057%), and secreted HGF(16 -18 ng/4 x 10(5) cells) and VEGF proteins. The expressing product could significantly stimulate proliferation of human umbilical vein endothelial cells, in a dose-dependent manner (P < 0.05).

CONCLUSION

pUDKH has the potential application in vivo to treat ischemic diseases.