Proteomic analysis of global protein expression changes in the endothelin-1 rat model for cerebral ischemia: Rescue effect of mild hypothermia

Mild hypothermia is a promising neuroprotective therapy in stroke management. However, little is known about its effects on the global protein expression patterns in brain regions affected by ischemic stroke. We investigated protein expression changes associated with the neuroprotective effects of hypothermia via a functional proteomics approach through the analysis of the core (striatum) and the penumbra (cortex) after an ischemic insult in rats induced by endothelin-1 (Et-1). Functional outcome, infarct volume and related global protein expression changes were assessed 24 h after the insult using two-dimensional difference gel electrophoresis. Mild hypothermia, induced 20 min after endothelin-1 infusion, improved the neurological outcome, reflected by a 36% reduction in infarct volume and a significantly better neurological deficit score. Hypothermia was typically associated with opposite protein expression changes inthe cortex to those induced by stroke under normothermic conditions, but not in the striatum. The main cellular processes rescued by hypothermia and potentially involved in the protection of the cortex are cellular assembly and organization, followed by cell signaling, thereby confirming that hypothermia is neuroprotective through multiple molecular and cellular pathways.     

Heritability and Clinical Determinants of Serum Indoxyl Sulfate and p-Cresyl Sulfate,Candidate Biomarkers of the Human Microbiome Enterotype

Background

Indoxyl sulfate and p-cresyl sulfate are unique microbial co-metabolites. Both co-metabolites have been involved in the pathogenesis of accelerated cardiovascular disease and renal disease progression. Available evidence suggests that indoxyl sulfate and p-cresyl sulfate may be considered candidate biomarkers of the human enterotype and may help to explain the link between diet and cardiovascular disease burden.

Objective and Design

Information on clinical determinants and heritability of indoxyl sulfate and p-cresyl sulfate serum is non-existing. To clarify this issue, the authors determined serum levels of indoxyl sulfate and p-cresyl sulfate in 773 individuals, recruited in the frame of the Flemish Study on Environment, Genes and Health Outcomes (FLEMENGHO study).

Results

Serum levels of indoxyl sulfate and p-cresyl sulfate amounted to 3.1 (2.4–4.3) and 13.0 (7.4–21.5) μM, respectively. Regression analysis identified renal function, age and sex as independent determinants of both co-metabolites. Both serum indoxyl sulfate (h² = 0.17) and p-cresyl sulfate (h² = 0.18) concentrations showed moderate but significant heritability after adjustment for covariables, with significant genetic and environmental correlations for both co-metabolites.

Limitations

Family studies cannot provide conclusive evidence for a genetic contribution, as confounding by shared environmental effects can never be excluded.

Conclusions

The heritability of indoxyl sulfate and p-cresyl sulfate is moderate. Besides genetic host factors and environmental factors, also renal function, sex and age influence the serum levels of these co-metabolites.     

Randomised Double-Blind Comparison of Placebo and Active Drugs for Effects on Risks Associated with Blood Pressure Variability in the Systolic Hypertension in Europe Trial

Background

In the Systolic Hypertension in Europe trial ({"type":"clinical-trial","attrs":{"text":"NCT02088450","term_id":"NCT02088450"}}NCT02088450), we investigated whether systolic blood pressure variability determines prognosis over and beyond level.

Methods

Using a computerised random function and a double-blind design, we randomly allocated 4695 patients (≥60 years) with isolated systolic hypertension (160–219/<95 mm Hg) to active treatment or matching placebo. Active treatment consisted of nitrendipine (10–40 mg/day) with possible addition of enalapril (5–20 mg/day) and/or hydrochlorothiazide (12.5–25.0 mg/day). We assessed whether on-treatment systolic blood pressure level (SBP), visit-to-visit variability independent of the mean (VIM) or within-visit variability (WVV) predicted total (n = 286) or cardiovascular (n = 150) mortality or cardiovascular (n = 347), cerebrovascular (n = 133) or cardiac (n = 217) endpoints.

Findings

At 2 years, mean between-group differences were 10.5 mm Hg (p<0.0001) for SBP, 0.29 units (p = 0.20) for VIM, and 0.07 mm Hg (p = 0.47) for WVV. Active treatment reduced (p≤0.048) cardiovascular (−28%), cerebrovascular (−40%) and cardiac (−24%) endpoints. In analyses dichotomised by the median, patients with low vs. high VIM had similar event rates (p≥0.14). Low vs. high WVV was not associated with event rates (p≥0.095), except for total and cardiovascular mortality on active treatment, which were higher with low WVV (p≤0.0003). In multivariable-adjusted Cox models, SBP predicted all endpoints (p≤0.0043), whereas VIM did not predict any (p≥0.058). Except for an inverse association with total mortality (p = 0.042), WVV was not predictive (p≥0.15). Sensitivity analyses, from which we excluded blood pressure readings within 6 months after randomisation, 6 months prior to an event or both were confirmatory.

Conclusions

The double-blind placebo-controlled Syst-Eur trial demonstrated that blood-pressure lowering treatment reduces cardiovascular complications by decreasing level but not variability of SBP. Higher blood pressure level, but not higher variability, predicted risk.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT02088450","term_id":"NCT02088450"}}NCT02088450     

NMR and pattern recognition can distinguish neuroinflammation and peripheral inflammation

Multiple Sclerosis (MScl) is a neurodegenerative disease of the CNS, associated with chronic neuroinflammation. Cerebrospinal fluid (CSF), being in closest interaction with CNS, was used to profile neuroinflammation to discover disease-specific markers. We used the commonly accepted animal model for the neuroinflammatory aspect of MScl: the experimental autoimmune/allergic encephalomyelitis (EAE). A combination of advanced (1)H NMR spectroscopy and pattern recognition methods was used to establish the metabolic profile of CSF of EAE-affected rats (representing neuroinflammation) and of two control groups (healthy and peripherally inflamed) to detect specific markers for early neuroinflammation. We found that the CSF metabolic profile for neuroinflammation is distinct from healthy and peripheral inflammation and characterized by changes in concentrations of metabolites such as creatine, arginine, and lysine. Using these disease-specific markers, we were able to detect early stage neuroinflammation, with high accuracy in a second independent set of animals. This confirms the predictive value of these markers. These findings from the EAE model may help to develop a molecular diagnosis for the early stage MScl in humans.     

Backwash intensity and frequency impact the microbial community structure and function in a fixed-bed biofilm reactor

Linkages among bioreactor operation and performance and microbial community structure were investigated for a fixed-bed biofilm system designed to remove perchlorate from drinking water. Perchlorate removal was monitored to evaluate reactor performance during and after the frequency and intensity of the backwash procedure were changed, while the microbial community structure was studied using clone libraries and quantitative PCR targeting the 16S rRNA gene. When backwash frequency was increased from once per month to once per day, perchlorate removal initially deteriorated and then recovered, and the relative abundance of perchlorate-reducing bacteria (PRB) initially increased and then decreased. This apparent discrepancy suggested that bacterial populations other than PRB played an indirect role in perchlorate removal, likely by consuming dissolved oxygen, a competing electron acceptor. When backwash intensity was increased, the reactor gradually lost its ability to remove perchlorate, and concurrently the relative abundance of PRB decreased. The results indicated that changes in reactor operation had a profound impact on reactor performance through altering the microbial community structure. Backwashing is an important yet poorly characterized procedure when operating fixed-bed biofilm reactors. Compared to backwash intensity, changes in backwash frequency exerted less disturbance on the microbial community in the current study. If this finding can be confirmed in future work, backwash frequency may serve as the primary parameter when optimizing backwash procedures.     

Diversity and dynamics of microbial communities in engineered environments and their implications for process stability

The availability of molecular biological tools for studying microbial communities in bioreactors and other engineered systems has resulted in remarkable insights linking diversity and dynamics to process stability. As engineered systems are often more manageable than large-scale ecosystems, and because parallels between engineered environments and other ecosystems exist, the former can be used to elucidate some unresolved ecological issues. For example, the process stability of methanogenic bioreactors containing well-defined trophic groups appears to depend on the diversity of the functional groups within each trophic level as well as on how these functional groups complement each other. In addition to using engineered systems to study general ecological questions, microbial ecologists and environmental engineers need to investigate conditions, processes, and interactions in engineered environments in order to make the ecological engineering of bioreactor design and operation more practicable.     

Advanced HIV Disease at Enrolment in HIV Care: Trends and Associated Factors over a Ten Year Period in Cambodia

Background

Early HIV diagnosis and enrolment in care is needed to achieve early antiretroviral treatment (ART) initiation. Studies on HIV disease stage at enrolment in care from Asian countries are limited. We evaluated trends in and factors associated with late HIV disease presentation over a ten-year period in the largest ART center in Cambodia.

Methods

We conducted a retrospective analysis of program data including all ARV-naïve adults (> 18 years old) enrolling into HIV care from March 2003-December 2013 in a non-governmental hospital in Phnom Penh, Cambodia. We calculated the proportion presenting with advanced stage HIV disease (WHO clinical stage IV or CD4 cell count <100 cells/μL) and the probability of ART initiation by six months after enrolment. Factors associated with late presentation were determined using multivariate logistic regression.

Results

From 2003–2013, a total of 5642 HIV-infected patients enrolled in HIV care. The proportion of late presenters decreased from 67% in 2003 to 44% in 2009 and 41% in 2013; a temporary increase to 52% occurred in 2011 coinciding with logistical/budgetary constraints at the national program level. Median CD4 counts increased from 32 cells/μL (IQR 11–127) in 2003 to 239 cells/μL (IQR 63–291) in 2013. Older age and male sex were associated with late presentation across the ten-year period. The probability of ART initiation by six months after enrolment increased from 22.6% in 2003–2006 to 79.9% in 2011–2013.

Conclusion

Although a gradual improvement was observed over time, a large proportion of patients still enroll late, particularly older or male patients. Interventions to achieve early HIV testing and efficient linkage to care are warranted.