Effects of continuous positive airway pressure therapy on plasma aldosterone levels in patients with obstructive sleep apnea: A meta-analysis.

Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular diseases. Aldosterone was reported to be increased in patients with OSA and correlated with OSA severity. Many studies investigated the effect of continuous positive airway pressure (CPAP) therapy on plasma aldosterone concentrations (PAC) in OSA patients. The results, however, were inconsistent. In the present study, we aimed to evaluate the effects of CPAP therapy on PAC by performing a meta-analysis. Literature search was carried out in electronic databases including PubMed/Medline, Cochrane Library, Embase and Web of Science. Eligible full-text articles were identified, and important data were extracted. Pooled analysis was performed using the STATA12.0 and RevMan 5.2. Standardized mean difference (SMD) was calculated to estimate the treatment effects. A total of eight studies involving 219 patients were included for our final analysis. PAC was found unchanged after CPAP treatment in OSA patients (SMD=-0.36, 95% CI:-0.91 to 0.18, Z=1.32, P=0.19). Meanwhile, CPAP therapy showed no impact on PAC (SMD=-0.21, 95% CI:-0.85 to 0.42, Z=0.66, P=0.51) in a separate meta-analysis including 3 randomized controlled trials. In conclusion, the evidence for the use of CPAP therapy to decrease PAC in OSA patients is low, and further studies are still warranted.

A new method for evaluating regional cerebral blood flow changes: Laser speckle contrast imaging in a C57BL/6J mouse model of photothrombotic ischemia.

The present study aimed to improve the processing of data acquired from laser speckle contrast imaging (LSCI) to provide a standardization method to explore changes in regional cerebral blood flow (rCBF) and to determine the correlations among rCBF, cerebral ischemic lesion volume and microvascular density over time in a focal ischemic region. C57BL/6J mice were subjected to focal photothrombotic (PT) ischemia. rCBF was measured using LSCI at different time points before and after PT ischemia through an intact skull. Standardized rCBF (SrCBF), defined as the ratio of rCBF measured in the ipsilateral region of interest (ROI) to that in the corresponding contralateral region, was calculated to evaluate potential changes. In addition, the volume of the ischemic lesion and the microvascular density were determined using Nissl staining and immunofluorescence, respectively. The relationships among the ischemic lesion volume, microvascular density and SrCBF were analyzed over time. The results showed that the cortical rCBF measured using LSCI following PT ischemia in the C57BL/6J mice gradually increased. Changes in the cerebral ischemic lesion volume were negatively correlated with SrCBF in the ischemic region. Changes in the microvascular density were similar to those observed in SrCBF. Our findings indicate that LSCI is a practical technique for observing changes in murine cortical rCBF without skull opening and for analyzing the relationships among the ischemic lesion volume, microvascular density and SrCBF following focal cerebral ischemia. Preliminary results also suggest that the use of LSCI to observe the formation of collateral circulation is feasible.

Transient folate deprivation in combination with small-molecule compounds facilitates the generation of somatic cell-derived pluripotent stem cells in mice.

Induced pluripotent stem cells (iPSCs) can be propagated indefinitely, while maintaining the capacity to differentiate into all cell types in the body except for the extra-embryonic tissues. This iPSC technology not only represents a new way to use individual-specific stem cells for regenerative medicine but also constitutes a novel method to obtain large numbers of disease-specific cells for biomedical research. However, the low efficiency of reprogramming and genomic integration of oncogenes and viral vectors limit the potential application of iPSCs. Chemical-induced reprogramming offers a novel approach to generating iPSCs. In this study, a new combination of small-molecule compounds (SMs) (sodium butyrate, A-83-01, CHIR99021, Y-27632) under conditions of transient folate deprivation was used to generate iPSC. It was found that transient folate deprivation combined with SMs was sufficient to permit reprogramming from mouse embryonic fibroblasts (MEFs) in the presence of transcription factors, Oct4 and Klf4, within 25 days, replacing Sox2 and c-Myc, and accelerated the generation of mouse iPSCs. The resulting cell lines resembled mouse embryonic stem (ES) cells with respect to proliferation rate, morphology, pluripotency-associated markers and gene expressions. Deprivation of folic acid, combined with treating MEFs with SMs, can improve the inducing efficiency of iPSCs and reduce their carcinogenicity and the use of exogenous reprogramming factors.