HMGB1 mediates splenomegaly and expansion of splenic CD11b+ Ly-6C(high) inflammatory monocytes in murine sepsis survivors

BACKGROUND

More than 500,000 hospitalized patients survive severe sepsis annually in the USA. Recent epidemiological evidence, however, demonstrated that these survivors have significant morbidity and mortality, with 3-year fatality rates higher than 70%. To investigate the mechanisms underlying persistent functional impairment in sepsis survivors, here we developed a model to study severe sepsis survivors following cecal ligation and puncture (CLP).

METHODS

Sepsis was induced in mice by CLP and survivors were followed for twelve weeks. Spleen and blood were collected and analyzed at different time points post-sepsis.

RESULTS

We observed that sepsis survivors developed significant splenomegaly. Analysis of the splenic cellular compartments revealed a major expansion of the inflammatory CD11b+ Ly-6CHigh pool. Serum high-mobility group box 1 (HMGB1) levels in the sepsis surviving mice were significantly elevated for 4-6 weeks after post-sepsis, and administration of an anti-HMGB1 monoclonal antibody significantly attenuated splenomegaly as well as splenocyte priming. Administration of recombinant HMGB1 to naive mice induced similar splenomegaly, leukocytosis and splenocyte priming as observed in sepsis survivors. Interestingly analysis of circulating HMGB1 from sepsis survivors by mass spectroscopy demonstrated a stepwise increase of reduced form of HMGB1 (with known chemo-attractant properties) during the first 3 weeks, followed by disulphide form (with known inflammatory properties) 4-8 weeks after CLP.

DISCUSSION

Our results indicate that prolonged elevation of HMGB1 is a necessary and sufficient mediator of splenomegaly and splenocyte expansion, as well as splenocyte inflammatory priming in murine severe sepsis survivors.

Serum high-density lipoprotein cholesterol and progression to arterial stiffness in middle-aged and elderly Chinese

BACKGROUND AND AIMS

Low high-density lipoprotein cholesterol (HDL-c) is a risk factor for cardiovascular disease. Brachial-ankle pulse wave velocity (baPWV) is an indicator of arterial stiffness, which is recognized as a predictor of cardiovascular disease. The aim of this study was to investigate the association between HDL-c and baPWV among middle-aged and elderly Chinese.

METHODS

A total number of 1133 Chinese (430 men, 703 women) aged from 50 to 90 years old were recruited from Shanghai downtown district. The baPWV and major cardiovascular risk factors of the participants were measured.

RESULTS

Serum HDL-c was negatively correlated with baPWV (r = -0.143, P < 0.001) after adjustment for age and gender. Multivariate linear regression analysis demonstrated that age (P < 0.001), systolic blood pressure (P < 0.001), HDL-c (P < 0.001), smoking (P = 0.001), BMI (P = 0.002), fasting plasma glucose (P = 0.004), and white blood cell (P = 0.005) were independently associated with baPWV. After multiple adjustments, participants in the highest quartile of HDL-c had an odds ratio of 0.442 (95% CI 0.268-0.729) for developing high arterial stiffness compared with participants in the lowest quartile. The association remained significant after further adjustment for major cardiovascular risk factors.

CONCLUSION

HDL-c has an independent protective effect on arterial stiffness in middle-aged and elderly Chinese. Early detection of HDL-c level is important in high risk populations with arterial stiffness. Increasing HDL-c level may be an attractive therapeutic target for the prevention of arterial function and subsequent disease.

Association between high aflatoxin B1 levels and high viral load in HIV-positive people

Since both aflatoxin and the human immunodeficiency virus (HIV) cause immune suppression, chronic exposure to aflatoxin in HIV-positive people could lead to higher levels of virus replication. This study was conducted to examine the association between aflatoxin B₁ albumin adduct (AF-ALB) levels and HIV viral load. Antiretroviral naive HIV-positive people (314) with median CD4 count of 574 cells/μl blood (mean ± standard deviation = 630±277) were recruited in Kumasi, Ghana. Sociodemographic and health data, and blood samples were collected from participants. The plasma samples were tested for AF-ALB and HIV viral load. Univariate logistic regression analysis was conducted using viral load (high/low) as the outcome and AF-ALB quartiles as exposure. Multivariable logistic regression analysis was performed between quartile AF-ALB, viral load and CD4 adjusting for sex, age, and year of HIV diagnosis. Both univariate and multivariable logistic regression showed that viral load increased as AF-ALB levels increased. By univariate analysis, high viral load was 2.3 times more likely among persons in the third AF-ALB quartile (95% confidence interval (Cl): 1.13, 4.51), and 2.9 times more likely among persons in the fourth AF-ALB quartile (Cl: 1.41, 5.88), compared to persons in the first quartile. In the multivariable model, persons in the fourth AF-ALB quartile were about 2.6 times more likely to have high viral loads than persons in the first quartile (Cl: 1.19-5.69). When AF-ALB and viral load were log transformed and linear regression analysis conducted, the univariate linear regression analysis showed that for each pg/mg increase in AF-ALB, viral load increased by approximately 1.6 copies/ml (P=0.0006). The association was marginally significant in the adjusted linear regression model (i.e. for each pg/mg increase in AF-ALB, the mean viral load increased by approximately 1.3 copies/ml, P=0.073). These data show strong and consistent increases in HIV viral load with increasing AF-ALB levels. Since the median and mean CD4 were greater than 500 cells for participants in each AF-ALB quartile, the results indicate that the immune modulating and virus transcription effects of aflatoxin may occur quite early in HIV infection, even while the CD4 count is still above 500, resulting in higher viral loads.

GADD45β mediates p53 protein degradation via Src/PP2A/MDM2 pathway upon arsenite treatment

Growth arrest and DNA-damage-inducible, beta (GADD45β) has been reported to inhibit apoptosis via attenuating c-Jun N-terminal kinase (JNK) activation. We demonstrated here that GADD45β mediated its anti-apoptotic effect via promoting p53 protein degradation following arsenite treatment. We found that p53 protein expression was upregulated in GADD45β−/− cells upon arsenite exposure as compared with those in GADD45β+/+ cells. Further studies showed that GADD45β attenuated p53 protein expression through Src/protein phosphatase 2A/murine double minute 2-dependent p53 protein-degradation pathway. Moreover, we identified that GADD45β-mediated p53 protein degradation was crucial for its anti-apoptotic effect due to arsenite exposure, whereas increased JNK activation was not involved in the increased cell apoptotic response in GADD45β−/− cells under same experimental conditions. Collectively, our results demonstrate a novel molecular mechanism responsible for GADD45β protection of arsenite-exposed cells from cell death, which provides insight into our understanding of GADD45β function and a unique compound arsenite as both a cancer therapeutic reagent and an environmental carcinogen. Those novel findings may also enable us to design more effective strategies for utilization of arsenite for the treatment of cancers.

Osteocalcin, glucose metabolism, lipid profile and chronic low-grade inflammation in middle-aged and elderly Chinese

AIM

To assess the relationship between serum total osteocalcin and measurements of adiposity, glucose tolerance, lipid profile, adipokine and chronic low-grade inflammation in middle-aged and elderly Chinese subjects.

METHODS

We performed a cross-sectional community-based study in central Shanghai. Serum total osteocalcin was measured by radioimmunoassay in 783 men and 946 post-menopausal women. Their associations with measurements of adiposity, glucose tolerance, lipid profile and chronic low-grade inflammation were examined.

RESULTS

Serum total osteocalcin levels revealed a sexual dimorphism, with post-menopausal women having significantly higher levels than men (P < 0.001). Serum osteocalcin levels of participants with self-reported cardiovascular disease were significantly lower (P = 0.044) than those without. In men, serum osteocalcin levels of participants with the metabolic syndrome were significantly lower than those without the metabolic syndrome (P = 0.036). Serum osteocalcin correlated negatively with fasting serum insulin, homeostasis model assessment of insulin resistance, alanine aminotransferase, triglycerides and total cholesterol, and positively with homeostasis model assessment of β-cell function in both men and post-menopausal women (all P < 0.05). In men, serum osteocalcin correlated negatively with BMI, diastolic blood pressure, fasting plasma glucose and 2-h oral glucose tolerance test glucose after adjustment for age (all P < 0.05). In post-menopausal women, serum osteocalcin correlated negatively with waist-hip ratio, LDL cholesterol and C-reactive protein, and positively with adiponectin (all P < 0.05). Serum osteocalcin was not associated with CXC chemokine ligand 5 level (P > 0.05). Alanine aminotransferase was an independent predictor of serum osteocalcin in both men and post-menopausal women (both P < 0.001). Adiponectin was an independent predictor of serum osteocalcin in post-menopausal women (P = 0.011). Serum osteocalcin was an independent predictor of homeostasis model assessment of β-cell function in both genders (both P < 0.05).

CONCLUSIONS

Serum total osteocalcin was closely associated with glucose and lipid metabolism in both Chinese men and post-menopausal women.

Mean peak systolic velocity of the superior thyroid artery is correlated with radioactive iodine uptake in untreated thyrotoxicosis

OBJECTIVE

To evaluate the correlation between mean superior thyroid artery peak systolic velocity (STA-PSV) and radioactive iodine uptake (RAIU) in Chinese patients with untreated thyrotoxicosis, using retrospectively and prospectively collected data.

METHODS

Patients with untreated thyrotoxicosis (n = 220) and euthyroid control subjects (n = 30) underwent thyroid function, thyroid autoantibody and thyroid ultrasonography tests. Mean STA-PSV was measured by ultrasonography. RAIU tests identified 168 patients with Graves' disease and 52 with destructive thyroiditis. Linear correlation of mean STA-PSV with 3-h and 24-h RAIU, and sensitivity, specificity and receiver operating characteristic (ROC) curves for mean STA-PSV in the differential diagnosis of Graves' disease and destructive thyroiditis were calculated.

RESULTS

Mean STA-PSV was significantly higher in Graves' disease than in destructive thyroiditis. Mean STA-PSV correlated positively and significantly with 3-h and 24-h RAIU. Area under the ROC curve of mean STA-PSV for the differential diagnosis of Graves' disease and destructive thyroiditis was 0.825 (optimum cut-off value of mean STA-PSV, 45.25 cm/s; sensitivity, 80.4%; specificity, 81.4%).

CONCLUSIONS

Detection of mean STA-PSV by ultrasonography agrees with RAIU and is useful for the differential diagnosis of thyrotoxicosis in Chinese patients.

Association of leptin receptor gene polymorphisms and essential hypertension in a Chinese population

BACKGROUND

The leptin receptor (LEPR) is an important regulator of leptin activity and resistance. Several single nucleotide polymorphisms (SNP) of LEPR have been linked to diseases accompanying obesity and/or obesity-related diseases in different populations. However, the results from published studies remain inconsistent rather than conclusive.

AIM

To investigate whether LEPR SNP are associated with essential hypertension and related metabolic traits in Chinese subjects.

MATERIALS AND METHODS

A total of 544 Chinese patients with hypertension and 357 non-hypertensive subjects were screened. The genotypes of LEPR polymorphisms were determined by PCR-restriction fragment length polymorphism methods. Demographic and biochemical characteristics including waist circumference, waist-to-hip ratio, body mass index (BMI), lipids profiles, glucose metabolism, and leptin levels were obtained for analysis.

RESULTS

This case-control study showed associations between the frequencies of AA genotype and A allele of Gln223Arg and hypertension (p=0.029, p=0.002, respectively). Furthermore, the Gln223Arg polymorphism was significantly associated with plasma leptin levels (p<0.001), while no correlations between Lys109Arg SNP and hypertension were found. Multivariate logistic regression analysis evidenced that A allele carriers of Gln223Arg (AA+AG) showed higher risks of hypertension than GG carriers after adjustment of age and sex (adjusted odds ratio: 1.549, 95% confidence interval: 1.031- 2.036, p=0.035). BMI, fasting serum insulin, oral glucose tolernace test (OGTT)-2h glucose, serum leptin, as well as LDL-cholesterol (LDL-C) levels were also independent risk factors of hypertension in this population. In addition, significant associations were observed between the Gln223Arg and Lys109Arg SNP and serum total cholesterol, LDL-C, and fasting plasma glucose levels in hypertensive patients. Besides, A allele of Gln223Arg had raised diastolic blood pressure, compared with GG carriers (p=0.001). While variance of Lys109Arg was associated with waist-to-hip ratio, OGTT-2h glucose, and homeostasis model assessment of insulin resistance (p<0.05).

CONCLUSIONS

LEPR polymorphisms may be a marker for susceptibility to essential hypertension in Chinese subjects, and be involved in the development of several features including dyslipidemia and impaired glucose regulation in hypertension subjects.

Upgrades of the high resolution imaging x-ray crystal spectrometers on experimental advanced superconducting tokamak

Two imaging x-ray crystal spectrometers, the so-called "poloidal" and "tangential" spectrometers, were recently implemented on experimental advanced superconducting tokamak (EAST) to provide spatially and temporally resolved impurity ion temperature (T(i)), electron temperature (T(e)) and rotation velocity profiles. They are derived from Doppler width of W line for Ti, the intensity ratio of Li-like satellites to W line for Te, and Doppler shift of W line for rotation. Each spectrometer originally consisted of a spherically curved crystal and a two-dimensional multi-wire proportional counter (MWPC) detector. Both spectrometers have now been upgraded. The layout of the tangential spectrometer was modified, since it had to be moved to a different port, and the spectrometer was equipped with two high count rate Pilatus detectors (Model 100 K) to overcome the count rate limitation of the MWPC and to improve its time resolution. The poloidal spectrometer was equipped with two spherically bent crystals to record the spectra of He-like and H-like argon simultaneously and side by side on the original MWPC. These upgrades are described, and new results from the latest EAST experimental campaign are presented.