Impacts of Different Anesthetic Agents on Left Ventricular Systolic Function in Mice Assessed by Echocardiography

The present experiments were performed to study the effects and time trends of different anesthetic agents on the left ventricular (LV) systolic function and heart rate by high-resolution echocardiography in mice. Ten male C57BL/6J mice were submitted to echocardiography imaging separated by 72-hour intervals under the following conditions: 1) conscious mice, 2) mice anesthetized with isoflurane (ISO, inhaled), 3) mice anesthetized with tribromoethanol (TBE, intraperitoneal), 4) mice anesthetized with chloral hydrate (CH, intraperitoneal), and 5) mice anesthetized with pentobarbital sodium (PS, intraperitoneal). The effect of ISO, TBE, CH, and PS on LV systolic function was measured at 0, 1, 2, 3, 4, 6, 8, and 10 min after anesthesia. The results showed that LV systolic function and heart rate (HR) of anesthetized mice were reduced significantly (P<0.05), compared with results in the same mice studied in the conscious state. In addition, the results indicated that the anesthetic with the least effect on LV function was CH, and followed by TBE, PS, ISO. We conclude that different anesthetic agents always depressed the HR and LV systolic function of mice, and, furthermore, the effects and time trends of different anesthetics on LV function are different. In echocardiographic experiments, we should choose proper anesthetic agents according to the experimental requirements.

Abstract 514: Netrin 4 Deficiency Leads to Endothelial Cell Senescence

Senescence phenotype of endothelial cells (ECs) has pathophysiological consequences, such as decreased regeneration capacity, pro-atherogenic tendency and dysregulated vessel tune. We find that netrin 4 (NTN4), recognized in neural and vascular development, is highly expressed by mature ECs. Remarkably, little is known about its role in vascular biology after development. NTN4 is deposited in the extracellular matrix. Using human decellularized kidney extracelluar matrix scaffolds, we found that pre-treatment of the scaffolds with NTN4 increased numbers of EC adhesion to the matrix, showing a pro-survival effect of NTN4.

Subsequently we explored the regulation of NTN4 expression in ECs. We found a 1.8-fold (±0.3; p<0.05) upregulation in NTN4 expression in ECs cultured under laminar flow conditions compared to static culture conditions. In contrast, ECs stimulated with TNFα resulted in decreased NTN4 expression (0.17 ± 0.06 fold; p<0.05), indicating a role for NTN4 in quiescent healthy endothelium. Silencing of NTN4 in ECs, to investigate the necessity of NTN4 in ECs, markedly resulted in more senescent associated β-galactosidase activity (20-50%; p<0.05) that could be rescued by NTN4 protein coating. Consistent with increased senescence, NTN4 reduction is accompanied with increased expression of senescence-associated transcription factors, CDKN1A and CDKN2A, as well as decreased ability to proliferate. Importantly, ECs with reduced levels of NTN4 have also increased expression of ICAM-1 and VCAM-1, are more prone to adhesion of human monocyte and have impaired barrier function, measured in an electric cell-substrate impedance sensing system as well as ‘organ-on-a-chip’ microfluidic system.

In conclusion, our results identified the anti-senescence function of NTN4 and thereby provides novel insights in the role of NTN4 in EC function. In situations like acute inflammation and unfavourable hemodynamic conditions, NTN4 expression decreases, so that there is a possible window for us to improve EC function by normalizing NTN4 expression.

Osteopontin is associated with inflammation and mortality in a mouse model of polymicrobial sepsis

BACKGROUND

Osteopontin (OPN) is a multifunctional glycoprotein with pro-inflammatory properties. In severe sepsis, levels of plasma OPN are significantly higher in non-survivors than in survivors. We hypothesized that OPN results in greater inflammation and worse outcome through modulation of endogenous glucocorticoid production in sepsis.

METHODS AND RESULTS

Sepsis was induced by cecal ligation and puncture (CLP) in wild type (WT) and OPN gene knockout (OPN(-/-) ) mice. In response to sepsis, the OPN(-/-) mice had lower levels of plasma cytokines and chemokines than the WT mice. The levels of corticosterone in plasma were similar between WT and OPN(-/-) sham animals but they increased 24 h after CLP induction in the WT mice, but not in the OPN(-/-) mice. The mortality rate was lower in the OPN(-/-) mice than in the WT mice.

CONCLUSION

OPN is associated with greater inflammatory response and increased mortality, despite the higher corticosterone levels in plasma. Corticosterone production is not impaired in the absence of OPN.

Recovery of gastrointestinal function with thoracic epidural vs. systemic analgesia following gastrointestinal surgery

The objective of this review was to systematically assess the effect of thoracic epidural analgesia (TEA) vs. systemic analgesia (SA) on the recovery of gastrointestinal (GI) function in patients following GI surgery. We performed a comprehensive literature search to identify randomized controlled trials of adult patients undergoing GI surgery, comparing the effect of two postoperative analgesia regimens. Patients postoperatively receiving local anesthesia-based TEA with or without opioids were compared to patients receiving opioid-based SA. The outcomes considered were times to GI function recovery, GI complications, and specific side effects. Twelve studies with 331 patients in the TEA group and 319 in the SA group were included. Compared to SA, TEA improved the GI recovery after GI procedures by shortening the time to first passage of flatus by 31.3 h, 95% confidence intervals (CIs): -33.2 to -29.4, P < 0.01; and shortening the time to first passage of stool by 24.1 h, 95% CIs: -27.2 to -20.9, P < 0.001. There was no difference between the groups in the incidence of anastomotic leakage and ileus. The occurrence of postoperative hypotension was relatively higher in the TEA group, risk ratio: 7.9, 95% CIs: 2.4 to 26.5, P = 0.001; other side effects (such as pruritus and vomiting) were similar in the two groups. There is evidence that TEA (compared to SA) improves the recovery of GI function after GI procedures without any increased risk of GI complications. To further confirm these effects, larger, better quality randomized controlled trials with standard outcome measurements are needed.

CALCULATION OFHO2DENSITY OF STATES ON THREE POTENTIAL ENERGY SURFACES

Density of states (DOS) in both bound and unimolecular dissociation regime for HO2system have been calculated quantum mechanically by Lanczos homogeneous filter diagonalization (LHFD) method. Three potential energy surfaces are explored and the results are contrasted for the total angular momentum J = 0 density of states. While two ab initio potential energy surfaces (PESs) (TU PES, J Chem Phys, 115:3621 and XXZLG PES, J Chem Phys122:244) produce the DOSs which are in fairly good agreement, the semi-empirical double many-body expansion (DMBE) IV PES (J Phys Chem94:8073) generates the much higher DOSs in higher energy range. The quantum mechanical DOSs are also compared with Troe et al.'s results from harmonic density, semiclassical density and their early density of states on the same TU ab initio surface.