To explore the role of mechanosensitive potassium channel TREK-1, Western blot analysis was used to investigate the expression changes of TREK-1 in left ventricle in acute mechanically stretched heart. Forty Wistar rats were randomly divided into 8 groups (n=5 in each group), subject to single Langendorff perfusion for 0, 30, 60, 120 min and acute mechanical stretch for 0, 30, 60, 120 min respectively. With Langendorff apparatus, an acute mechanically stretched heart model was established. There was no significant difference in the expression of TREK-1 among single Langendorff perfusion groups (P>0.05). As compared to non-stretched Langendorff-perfused heart, only the expression of TREK-1 in acute mechanically stretched heart (120 min) was greatly increased (P<0.05). This result suggested that some course of mechanical stretch could up-regulate the expression of TREK-1 in left ventricle. TREK-1 might play an important role in mechanoelectric feedback, so it could reduce the occurrence of arrhythmia that was induced by extra mechanical stretch.
Feedback ; Heart Ventricles/*metabolism ; Mechanotransduction, Cellular ; Potassium Channels, Tandem Pore Domain/*metabolism ; Random Allocation ; Rats, Wistar ; Stress, Mechanical

To explore the role of mechanosensitive potassium channel TREK-1, Western blot analysis was used to investigate the expression changes of TREK-1 in left ventricle in acute mechanically stretched heart. Forty Wistar rats were randomly divided into 8 groups (n=5 in each group),subject to single Langendorff perfusion for 0, 30, 60, 120 min and acute mechanical stretch for 0, 30,60, 120 min respectively. With Langendorff apparatus, an acute mechanically stretched heart model was established. There was no significant difference in the expression of TREK-1 among single Langendorff perfusion groups (P＞0.05). As compared to non-stretched Langendorff-perfused heart, only the expression of TREK-1 in acute mechanically stretched heart (120 min) was greatly increased (P＜0.05). This result suggested that some course of mechanical stretch could up-regulate the expression of TREK-1 in left ventricle. TREK-1 might play an important role in mechanoelectric feedback,so it could reduce the occurrence of arrhythmia that was induced by extra mechanical stretch.

Objective To compare the neurologic outcome after the active abdominal compression-decompression cardiopulmonary resuscitation (AACD-CPR) and chest compression cardiopulmonary resuscitation (STD-CPR) in asphyxia cardiac arrest (CA). Methods A prospective multicenter randomized controlled trial (RCT) was conducted. Adult patients with CA because of asphyxia such as drowning, airway obstruction admitted to Zhengzhou People's Hospital and Sanmenxia Central Hospital from June 2014 to December 2017 were enrolled. With the informed consent of patients' families, patients were divided into AACD-CPR group and STD-CPR group according to random number table method. The blood from median cubital vein or basilic vein were extracted at 1, 6, 12, 24 and 48 hours after the return of spontaneous circulation (ROSC), and the levels of S100B protein and neuron-specific enolase (NSE) were detected by enzyme linked immunosorbent assay. Neurological outcome was classified according to cerebral performance classification (CPC) after 3 months. Results A total of 183 patients were selected, including 78 ROSC patients after CPR. Patients with CA > 8 minutes and rescue time > 1 hour were excluded, 69 ROSC patients (36 in STD-CPR group and 33 in AACD-CPR group) were finally included. After ROSC, the levels of S100B protein and NSE in blood of two groups were increased gradually, reaching the peak at 6 hours, and then decreased gradually. The levels of S100B protein and NSE in AACD-CPR group at different time points after ROSC were significantly lower than those in STD-CPR group [S100B protein (μg/L): 1.62±0.52 vs. 1.88±0.46 at 1 hour, 1.71±0.41 vs. 2.02±0.58 at 6 hours, 1.24±0.37 vs. 1.52±0.59 at 12 hours, 1.05±0.23 vs. 1.28±0.37 at 24 hours, 0.82±0.29 vs. 1.05±0.36 at 48 hours; NSE (μg/L):24.76±3.02 vs. 26.78±4.29 at 1 hour, 58.78±5.58 vs. 61.68±5.44 at 6 hours, 53.87±4.84 vs. 56.78±5.68 at 12 hours, 40.96±3.52 vs. 43.13±4.50 at 24 hours, 33.23±2.89 vs. 35.54±3.44 at 48 hours; all P < 0.05]. 3 months after ROSC, the CPC classification of AACD-CPR group was lower than that of the STD-CPR group (average rank: 28.86 vs. 42.46, Z = -3.375, P < 0.001). Conclusion After suffering asphyxia CA, patients who accepted AACD-CPR had better neurologic outcome than STD-CPR.

The expression of stretch-activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the expression of TREK-1 mRNA and protein was detected by using semi quantitative RT PCR and Western blot respectively. At 4th and 8th week after constriction of the abdominal aorta, rats developed significant left ventricular hypertrophy. As compared to sham operated group, stretch activated potassium channel TREK-1 mRNA was strongly expressed and protein was up regulated in operation groups (P＜0.05). It was concluded that the expression of TREK 1 was up regulated in hypertrophic myocardium induced by chronic pressure overload in Wistar rats.

Objective To explore the predictive value of partial pressure of end-tidal carbon dioxide (PETCO2) on the effect of active abdominal compression-decompression cardiopulmonary resuscitation (AACD-CPR) and serum S100B protein on cerebral function. Methods 142 adult patients with in-hospital cardiac arrest (IHCA) AACD-CPR in Zhengzhou People's Hospital, Affiliated Southern Medical University from September 2014 to December 2017 were enrolled. Patients were divided into successful group and failure group according to restoration of spontaneous circulation (ROSC) or not; and then according to Glasgow-Pittsburgh cerebral performance categories (CPC) one month after ROSC, the successful group was divided into good prognosis group (CPC 1-2) and poor prognosis group (CPC 3-5) further. The variations of hemodynamic, arterial blood gas index, PETCO2and serum S100B protein level (25 healthy subjects as normal S100B protein level reference value) during the recovery were analyzed. The predictive value of PETCO2on the effect of AACD-CPR and serum S100B protein on cerebral function of successful resuscitation patients were analyzed by receiver operating characteristic curve (ROC). Results ① According to the traditional qualitative indexes, such as pulsation of the large artery, redness of lips and extremities, spontaneous fluctuation of chest, narrowing of pupil, existence of shallow reflex, etc, 54 in 142 patients with IHCA were successfully resuscitated; 57 cases were successfully resuscitated through the guidance of PETCO2, there was no significant difference between the two groups (χ2= 0.133, 1 = 0.715). With the AACD-CPR, 142 CA patients' arterial partial pressure of oxygen (PaO2), arterial blood carbon dioxide partial pressure (PaCO2) were all improved with different degrees; heart rate (HR), mean arterial pressure (MAP), PaO2and PaCO2were further improved at 20 minutes after ROSC. At beginning of AACD-CPR, PETCO2of both groups were about 10 mmHg (1 mmHg = 0.133 kPa). PETCO2was gradually rising to above 20 mmHg in successful group during AACD-CPR process; the failed group increased slightly within 2-5 minutes, then gradually decreased to below 20 mmHg, there was a significant difference in PETCO2between the two groups at each time. The area under the ROC (AUC) of PETCO2at CPR 20 minutes in predicting the outcome of the resuscitation was 0.969, 95% confidence interval (95%CI) was 0.943-0.995 (1 = 0.000), when the cut-off value of PETCO2was 24.25 mmHg, the sensitivity was 90.7%, and the specificity was 96.6%. ② The level of serum S100B protein at 0.5 hour after ROSC in the good prognosis group and the poor prognosis group were significant higher than that of the normal control group; there was no significant difference between poor prognosis group and good prognosis group. S100B protein concentration of the poor prognosis group reached the peak within 3-6 hours, then gradually decreased, and was higher than that of the normal control group at ROSC 72 hours; the good prognosis was gradually decreased and recovered to normal control group within ROSC 72 hours. The AUC of S100B at 3 hours after ROSC on cerebral function prognosis prediction was 0.925, 95%CI was 0.867-0.984 (1 = 0.000), when the cut-off value of S100B protein was 1.215 μg/L, the sensitivity was 85.2%, and the specificity was 85.5%. Conclusion The variation of PETCO2can be used as an objective index to predict the success of AACD-CPR, and serum S100B protein can be used as an objective clinical index to predict cerebral function after AACD-CPR, both of which have some reference and guiding significance for clinical treatment.