CXCR4 attenuates cardiomyocytes mitochondrial dysfunction to resist ischaemia-reperfusion injury.

The chemokine (C-X-C motif) receptor 4 (CXCR4) is expressed on native cardiomyocytes and can modulate isolated cardiomyocyte contractility. This study examines the role of CXCR4 in cardiomyocyte response to ischaemia-reperfusion (I/R) injury. Isolated adult rat ventricular cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) to simulate I/R injury. In response to H/R injury, the decrease in CXCR4 expression was associated with dysfunctional energy metabolism indicated by an increased adenosine diphosphate/adenosine triphosphate (ADP/ATP) ratio. CXCR4-overexpressing cardiomyocytes were used to determine whether such overexpression (OE) can prevent bio-energetic disruption-associated cell death. CXCR4 OE was performed with adenoviral infection with CXCR4 encoding-gene or non-translated nucleotide sequence (Control). The increased CXCR4 expression was observed in cardiomyocytes post CXCR4-adenovirus transduction and this OE significantly reduced the cardiomyocyte contractility under basal conditions. Although the same extent of H/R-provoked cytosolic calcium overload was measured, the hydrogen peroxide-induced decay of mitochondrial membrane potential was suppressed in CXCR4 OE group compared with control group, and the mitochondrial swelling was significantly attenuated in CXCR4 group, implicating that CXCR4 OE prevents permeability transition pore opening exposure to overload calcium. Interestingly, this CXCR4-induced mitochondrial protective effect is associated with the enhanced signal transducer and activator of transcription 3 (expression in mitochondria. Consequently, in the presence of H/R, mitochondrial dysfunction was mitigated and cardiomyocyte death was decreased to 65% in the CXCR4 OE group as compared with the control group. I/R injury leads to the reduction in CXCR4 in cardiomyocytes associated with the dysfunctional energy metabolism, and CXCR4 OE can alleviate mitochondrial dysfunction to improve cardiomyocyte survival.

Efficacy and safety of lubiprostone for the treatment of functional constipation in Chinese adult patients: A multicenter, randomized, double-blind, placebo-controlled trial.

OBJECTIVES: Functional constipation is a gastrointestinal disorder prevalent around the world. Lubiprostone is the first locally acting type-2 chloride channel activator to be used for treating constipation. This study aimed to evaluate the efficacy and safety of lubiprostone in Chinese adults with functional constipation. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled study. Patients with functional constipation were randomized to receive either lubiprostone (24 mcg twice daily) or placebo for 4 weeks. The primary end-point was the frequency of spontaneous bowel movements (SBMs) during the first week of treatment. The secondary end-points included the median time of the first SBM, SBM frequency at weeks 2, 3 and 4, weekly response rate of SBMs, the stool consistency score and average number of complete spontaneous bowel movements (CSBMs) per week. RESULTS: In total, 259 patients were randomized, with 130 in the lubiprostone group and 129 in the placebo group. SBM frequency was higher in the lubiprostone group (4.88 ± 4.09/wk) than that in the placebo group (3.22 ± 2.01/wk) at week 1 (P < 0.0001). SBM frequency was also higher in the lubiprostone group at weeks 2, 3 and 4. The average number of CSBMs and the stool consistency score in the lubiprostone group were significantly higher than that in the placebo group at each week. No drug-related serious adverse events (AEs) occurred. The most commonly reported AE was nausea. CONCLUSION: Lubiprostone was superior to placebo in treating Chinese patients with functional constipation, together with good safety profile.

Baicalin protects neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the phosphoinositide 3-kinase/protein kinase B signaling pathway.

Baicalin is a flavonoid compound extracted from Scutellaria baicalensis root. Recent evidence indicates that baicalin is neuroprotective in models of ischemic stroke. Here, we investigate the neuroprotective effect of baicalin in a neonatal rat model of hypoxic-ischemic encephalopathy. Seven-day-old pups underwent left common carotid artery ligation followed by hypoxia (8% oxygen at 37°C) for 2 hours, before being injected with baicalin (120 mg/kg intraperitoneally) and examined 24 hours later. Baicalin effectively reduced cerebral infarct volume and neuronal loss, inhibited apoptosis, and upregulated the expression of p-Akt and glutamate transporter 1. Intracerebroventricular injection of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) inhibitor LY294002 30 minutes before injury blocked the effect of baicalin on p-Akt and glutamate transporter 1, and weakened the associated neuroprotective effect. Our findings provide the first evidence, to our knowledge that baicalin can protect neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the PI3K/Akt signaling pathway.

[Study on quasispecies of hepatitis B virus and the clinical manifestation of their infection by melt curve analysis].

OBJECTIVES: To study the relationship between quasispecies of hepatitis B virus and the clinical manifestations of their infection, and to find the answer of why different quasispecies of HBV with the same genotype can induce different clinical situations. METHODS: Sixty serum samples, in all of which HBVs of genotype B exist, taken from 32 chronic asymptomatic carriers and 28 severe chronic hepatitis patients, were collected to detect quasispecies of HBV DNA by melt curve approach. Then the relationship between quasispecies of HBV of the same genotype and the clinical situation of their infection was studied by comparing the wave crests of the two sample groups. RESULTS: The data of the 60 serum samples of HBV of genotype B detected by melt curve showed that HBV DNA in severe chronic hepatitis patients had more wave crests than that in chronic asymptomatic carriers (P < 0.05), suggesting that HBV in severe chronic hepatitis patients had more quasispecies than in the chronic asymptomatic carriers. CONCLUSION: The numbers of quasispecies of HBV correlate with the clinical situations of their infection. In the patients infected by HBV of the same genotype, those who have more HBV quasispecies would have more severe clinical manifestations.

Repair Injured Heart by Regulating Cardiac Regenerative Signals.

Cardiac regeneration is a homeostatic cardiogenic process by which the sections of malfunctioning adult cardiovascular tissues are repaired and renewed employing a combination of both cardiomyogenesis and angiogenesis. Unfortunately, while high-quality regeneration can be performed in amphibians and zebrafish hearts, mammalian hearts do not respond in kind. Indeed, a long-term loss of proliferative capacity in mammalian adult cardiomyocytes in combination with dysregulated induction of tissue fibrosis impairs mammalian endogenous heart regenerative capacity, leading to deleterious cardiac remodeling at the end stage of heart failure. Interestingly, several studies have demonstrated that cardiomyocyte proliferation capacity is retained in mammals very soon after birth, and cardiac regeneration potential is correspondingly preserved in some preadolescent vertebrates after myocardial infarction. There is therefore great interest in uncovering the molecular mechanisms that may allow heart regeneration during adult stages. This review will summarize recent findings on cardiac regenerative regulatory mechanisms, especially with respect to extracellular signals and intracellular pathways that may provide novel therapeutics for heart diseases. Particularly, both in vitro and in vivo experimental evidences will be presented to highlight the functional role of these signaling cascades in regulating cardiomyocyte proliferation, cardiomyocyte growth, and maturation, with special emphasis on their responses to heart tissue injury.

[Relation between genotype of HBV and its clinical manifestation by PCR with genotype-specific primers].

OBJECTIVE: To determine the relation between genotype of HBV and its clinical manifestation. METHODS: Sera of 220 patients from Hunan Province of China, infected chronically with asymptomatic, mild, moderate, severe and fulminant hepatitis hepatitis B, were genotyped by PCR with genotype-specific primers. The results were statistically analyzed. RESULTS: Only genotype B (86.4%) and C (13.6%) were found. With the aggravations of patients' condition, genotype C was found more often (P < 0.05). The levels of alanine aminotransferase (ALT), total bilirubin (TBIL) and HBV-DNA of genotype C was higher than those of genotype B, but there was no statistical difference. However, the ALT elevation rates of genotype C (96.7%) were significantly higher than those of genotype B (75.2%) (P < 0.05). There was no statistical difference in HBeAg rate between genotype B and C in general, but in patients with chronic fulminant hepatitis or aged 21 approximately 30, the HBeAg rates of genotype C (35.0% and 50.0%) were significantly higher than those of genotype B (14.4% and 24.5%) (P < 0.05). CONCLUSION: The dominant genotype of HBV in Hunan Province of China is genotype B and C. Genotype of HBV correlates with its clinical manifestation and genotype C of HBV can lead to more severe hepatitis than genotype B of HBV.