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(1) Background: Along with an increasing risk caused by migrant workers returning to the urban areas for the resumption of work and production and growing epidemiological evidence of possible transmission during the incubation period, a study of Coronavirus Disease 2019 (COVID-19) is warranted among key populations to determine the serum antibody against the SARS-CoV-2 and the carrying status of SARS-CoV-2 to identify potential asymptomatic infection and to explore the risk factors. (2) Method: This is a cross-sectional seroepidemiologic study. Three categories of targeted populations (close contacts, migrant workers who return to urban areas for work, and school children) will be included in this study as they are important for case identification in communities. A multi-stage sampling method will be employed to acquire an adequate sample size. Assessments that include questionnaires and blood, nasopharyngeal specimens, and feces collection will be performed via home-visit survey. (3) Ethics and Dissemination: The study was approved by the Institute Review Board of School of Public Health, Fudan University (IRB#2020-04-0818). Before data collection, written informed consent will be obtained from all participants. The manuscripts from this work will be submitted for publication in quality peer-reviewed journals and presented at national or international conferences.

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We will investigate the effects of exenatide on vascular endothelial injury and nitrooxidative stress in hyperglycemia both in vivo and in vitro and explore the role of nitrooxidative stress in endothelium-protective action of exenatide. Healthy male Wistar rats were randomly divided into 4 groups: control, diabetes mellitus (DM) model, low dose of exenatide treatment, and high dose of exenatide treatment. In vitro study showed that, compared with control group, the DM rats exhibited a lowered endothelium-dependent relaxation and damaged structural integrity of thoracic aortas, and there was a significant increase in plasma nitrotyrosine concentration. These parameters were improved after treatment with either low dose or high dose of exenatide for 45 days. In vitro study showed that exendin-4 (the active ingredient of exenatide) attenuated HUVECs injury induced by high glucose, with improving cell viability and attenuating cell apoptosis. Exendin-4 also significantly alleviated the increased malondialdehyde (MDA), nitrotyrosine content, and inducible nitric oxide synthase (iNOS) expression induced by high glucose in HUVECs. In conclusion, this study demonstrates that exenatide treatment can alleviate the vascular endothelial injury, as well as attenuating the nitrooxidative stress in hyperglycemia, implying that the endothelium-protective effect of exenatide might be related to the reduction of nitrooxidative stress.

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BACKGROUND: Although agonistic autoantibodies against type-1 angiotensin-II receptor (AT1-AA) are frequently detected in women with preeclampsia, the clinical significance of AT1-AA in association with epithelial ovarian cancer (EOC) has not been identified. METHODS: In an attempt to clarify this issue, we measured serum AT1-AA titer from EOC patients (n = 89) and healthy normal subjects (n = 55), correlated AT1-AA titer with EOC stage and grade, and demonstrated the effects of purified AT1-AA on migration of ovarian cancer cells and angiogenesis of chick embryo chorioallantoic membrane. RESULTS: We found that the AT1-AA titer was significantly higher in EOC patients compared with healthy control subjects (1.77 ± 0.28 vs. 0.35 ± 0.05, P < 0.01). The positive rate was averaged by 72.1±2.5% in EOC patients and 15.5 ±1.5% in control (P < 0.01). Increased AT1-AA titer in EOC patients was associated with advanced stages and grades of EOC, and positively correlated with level of vascular endothelial growth factor (r = 0.855, P < 0.01). Furthermore, AT1-AA directly stimulated migration of ovarian cancer cells and enhanced microvascular density of chick embryo chorioallantoic membrane. These AT1-AA-mediated effects were significantly blocked either by an autoantibody-neutralizing peptide or an angiotensin II type I receptor antagonist, losartan. CONCLUSION: Taken together, we found that a higher serum AT1-AA titer may be associated with advanced progression of EOC in patients and play an important role in development of EOC by promoting cancer cell migration and angiogenesis. These findings implicate that AT1-AA might be selected as a detectable biomarker and potential therapeutic target in diagnosis and treatment of EOC patients.

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Antibody against the angiotensin AT1 receptor (AT1-Ab) could disturb placental development. The placenta is the key organ between mother and fetus. Placental damage will seriously impair fetal growth and development in utero, leading to intrauterine growth restriction (IUGR). Based on the fetal origins of adult disease (FOAD) hypothesis, IUGR could increase a propensity to develop adult onset cardiovascular disease (CVD). The present study was designed to determine whether vascular function has changed in the adult offspring of AT1-Ab positive pregnant rats. Twenty four female rats (8-week-old, AT1-Ab negative) were randomly divided into two groups, immunized and vehicle groups. Immunized group received active immunization to establish AT1-Ab-positive model, while vehicle group was subjected to Freund's adjuvant without antigen. After 8 weeks of immunization, the antibody titers in sera from the female rats were detected by enzyme-linked immunosorbent assay (ELISA). Then all the female rats were mated with normal Wistar male rats and became pregnant. Immunized/vehicle group offspring rats (I offspring/V offspring) were raised to 40-week-old under standard chow feeding. Then the two groups' offspring rats were given a high-salt diet for 12 weeks (4% NaCl in chow feeding). Systolic blood pressure (SBP) was measured dynamically by noninvasive blood pressure system. The vascular ring experiment was performed to detect vascular function and reactivity. As detected by ELISA, the titers of antibody peaked at the 8th week (OD values: 2.75 ± 0.08 vs 0.33 ± 0.01, P < 0.01 vs vehicle group at the same time point). There was no significant difference of SBP between the two groups' offspring rats during the high-salt diet (P > 0.05). Isolated thoracic aortic rings of I offspring had significantly decreased constriction under norepinephrine treatment (P < 0.01 vs V offspring) and significantly decreased dilation under acetylcholine treatment (P < 0.05 vs V offspring). These results suggest that the offspring of AT1-Ab-positive pregnant rats are more susceptible to vascular functional abnormality while being fed high-salt diet.

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Autophagy is a membrane process that results in the transporting of cellular contents to lysosomes for degradation. Autophagic cell death is another way of programed cell death called type II PCD, which has complicated connection with apoptosis, both of these two types of cell death play an important role in tumor development. In this study, we investigated chemotherapeutic agent induced cell death pathway in wild type (WT), Bax(-/-) and PUMA(-/-) HCT116 cells. Bax or PUMA deficient cells had similar chemosensitivity to WT cells but were defective in undergoing apoptosis. The results of electron microscopy and GFP-LC3 localization assay showed that autophagy was induced in Bax or PUMA deficient cells but not in WT cells. mTOR activity was decreased in Bax or PUMA deficient cells which further indicated the up-regulation of autophagy. Inhibition of autophagy by 3-Methyladenine (3-MA) decreased the cell death in Bax or PUMA deficient cells. Taken together, these results suggest that autophagic cell death can be used as an alternative cell death pathway in apoptosis defective cells and may bring a new target for cancer therapy.

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