Rapid Titration of Intravenous Treprostinil to Treat Severe Pulmonary Arterial Hypertension Postpartum: A Retrospective Observational Case Series Study.

BACKGROUND: Pulmonary hypertension during pregnancy carries high mortality rate. The relatively long-acting, specific pulmonary vasodilator treprostinil has been used to improve survival in these parturients. Slow uptitration is performed in most cases, and rapid titration has not been reported in the postpartum period. METHODS: We retrospectively reviewed 17 pregnant patients with severe pulmonary arterial hypertension who were treated with intravenous treprostinil in our institution between 2014 and 2016. Patients' demographic characteristics, etiology, functional status, mode of delivery, anesthetic administration, medical therapy, echocardiographic and hemodynamic measurements, subsequent clinical course, and maternal-fetal outcomes were assessed. The a priori primary outcome is maternal mortality in this study. RESULTS: Rapid titration of intravenous treprostinil was initiated at 1.25 ng/kg/min and increased to effective dose of 10 ng/kg/min by 1.25-2.5 ng/kg/min every 3 hours. In the next 24 hours, we adjusted the dosage to a median maximum dose of 15 ng/kg/min (interquartile range, 15-20 ng/kg/min) over a median uptitration period of 34 hours (interquartile range, 24-41 hours) for 17 parturients with severe pulmonary hypertension. Treprostinil was weaned off by 0.50-1.25 ng/kg/min every 3 hours in 94.3 ± 42.4 hours. Fifteen patients survived to discharge, and only 2 patients died of pulmonary hypertensive crisis (maternal mortality rate, 11.7%). No treprostinil infusion-related postpartum complication was observed. CONCLUSIONS: Our experience suggested that rapid uptitration of intravenous treprostinil combined with oral sildenafil in the postpartum period may be a safe and effective approach for these very sick parturients with severe pulmonary hypertension.

[The application of peripartum use of pulmonary artery catheter in pregnant patients with pulmonary hypertension].

OBJECTIVE: To investigate the application and value of pulmonary artery catheterization (PAC) in pregnant patients with pulmonary hypertension (PH). METHODS: The clinical data of pregnant patients with PH who were treated between 2006 and 2014 in surgical intensive care unit (SICU) at Capital Medical University affiliated Beijing Anzhen Hospital were retrospectively analysed. The differences of the clinical characteristics and outcome between PAC inserted patients and PAC not inserted patients were compared. RESULTS: The systolic pulmonary artery pressure (sPAP) measured by preoperative echocardiography has no significant difference between the PAC inserted patients [(103.0 ± 24.1) mmHg (1 mmHg = 0.133 kPa)] and PAC not inserted patients [(96.4 ± 27.3) mmHg; P = 0.175]. SPAP may be overestimated or underestimated by echocardiography compared with PAC with a gap from -38.4 mmHg to 49.5 mmHg. The rates of idiopathic pulmonary arterial hypertension (20.0% vs 3.2%) and continuous use of epidural anesthesia (89.1% vs 65.1%) were higher in PAC inserted patients compared with PAC not inserted patients. Norepinephrine, dobutamine, sildenafil, alprostadil, iloprost and low molecular weight heparin were more widely used in PAC inserted patients. The mortality rate and the rates of low birth weight (63.9% vs 30.6%) and very low birth weight infants (19.4% vs 13.9%) were all higher in PAC inserted patients, while the rate of induced abortion was lower in this group (5.5% vs 17.5%). The length of stay in surgical intensive care unit [6.0 (5.0) d vs 1.0 (3.0) d], postoperative length of stay [8.0 (6.0) d vs 8.0 (4.0) d] and total hospital costs [43 999.22 (38 267.27) RMB vs 14 878.24 (10 564.47) RMB] were all higher in PAC inserted patients. The incidence rate of PAC related complications was 7.3%. CONCLUSIONS: In moderate or severe PH pregnant patients with severe clinical symptoms, perioperative insertion of PAC helps to monitor the perinatal pulmonary arterial pressure(PAP) and guide treatment, potentially improving clinical outcomes and lowering the short term mortality. PAC can't be replaced by echocardiography in measuring PAP.

[Application of continuous renal replacement therapy in the treatment of myonephropathic metabolic syndrome caused by acute lower extremity ischemia].

OBJECTIVE: To summarize the experiences of using continuous renal replacement therapy in the treatment of myonephropathic metabolic syndrome caused by acute lower limb ischemia. METHODS: Retrospective study of patients diagnosed acute lower limb ischemia with surgical treatment between January 2008 and December 2013, among which 22 patients with myonephropathic metabolic syndrome received continuous renal replacement therapy. Summarize the change tendency of myoglobin, urine volume and serum creatinine levels during treatment and analysis the condition changes and prognosis of the patients. RESULTS: Among them, 2 patients were amputated and two died after surgery. The major causes of death were acute renal failure, metabolic acidosis, circulation failure and liver failure, etc. Myoglobin was significantly higher at Day 1 after surgery than that was before surgery (P < 0.05). Urine volume was significantly lower at Day 1 after surgery than that on the day of surgery (P < 0.05). CK was significantly lower at Day 2 after surgery than the day before (P < 0.05). Hemoglobin was significantly lower at Day 1 after surgery than that before surgery (P < 0.05). Serum creatinine levels remained steady. CONCLUSION: In patients of acute lower limb ischemia with myonephropathic metabolic syndrome, early targeted continuous renal replacement therapy may decrease the serum concentrations of myoglobin and CK, improve urine volume, maintain homeostasis, prevent renal function deterioration and improve the prognosis of patients. And it is highly recommended.

Stimulation of GLUT4 (glucose transporter isoform 4) storage vesicle formation by sphingolipid depletion.

Insulin stimulates glucose transport in fat and skeletal muscle cells primarily by inducing the translocation of GLUT4 (glucose transporter isoform 4) to the PM (plasma membrane) from specialized GSVs (GLUT4 storage vesicles). Glycosphingolipids are components of membrane microdomains and are involved in insulin-regulated glucose transport. Cellular glycosphingolipids decrease during adipocyte differentiation and have been suggested to be involved in adipocyte function. In the present study, we investigated the role of glycosphingolipids in regulating GLUT4 translocation. We decreased glycosphingolipids in 3T3-L1 adipocytes using glycosphingolipid synthesis inhibitors and investigated the effects on GLUT4 translocation using immunocytochemistry, preparation of PM sheets, isolation of GSVs and FRAP (fluorescence recovery after photobleaching) of GLUT4-GFP (green fluorescent protein) in intracellular structures. Glycosphingolipids were located in endosomal vesicles in pre-adipocytes and redistributed to the PM with decreased expression at day 2 after initiation of differentiation. In fully differentiated adipocytes, depletion of glycosphingolipids dramatically accelerated insulin-stimulated GLUT4 translocation. Although insulin-induced phosphorylation of IRS (insulin receptor substrate) and Akt remained intact in glycosphingolipid-depleted cells, both in vitro budding of GLUT4 vesicles and FRAP of GLUT4-GFP on GSVs were stimulated. Glycosphingolipid depletion also enhanced the insulin-induced translocation of VAMP2 (vesicle-associated membrane protein 2), but not the transferrin receptor or cellubrevin, indicating that the effect of glycosphingolipids was specific to VAMP2-positive GSVs. Our results strongly suggest that decreasing glycosphingolipid levels promotes the formation of GSVs and, thus, GLUT4 translocation. These studies provide a mechanistic basis for recent studies showing that inhibition of glycosphingolipid synthesis improves glycaemic control and enhances insulin sensitivity in animal models of Type 2 diabetes.

Development and Validation of a Diagnostic Model to Predict the Risk of Ischemic Liver Injury After Stanford A Aortic Dissection Surgery.

Objective: To define the risk factors of ischemic liver injury (ILI) following Stanford A aortic dissection surgery and to propose a diagnostic model for individual risk prediction. Methods: We reviewed the clinical parameters of ILI patients who underwent cardiac surgery from Beijing Anzhen Hospital, Capital Medical University between January 1, 2015 and October 30, 2020. The data was analyzed by the use of univariable and multivariable logistic regression analysis. A risk prediction model was established and validated, which showed a favorable discriminating ability and might contribute to clinical decision-making for ILI after Stanford A aortic dissection (AAD) surgery. The discriminative ability and calibration of the diagnostic model to predict ILI were tested using C statistics, calibration plots, and clinical usefulness. Results: In total, 1,343 patients who underwent AAD surgery were included in the study. After univariable and multivariable logistic regression analysis, the following variables were incorporated in the prediction of ILI: pre-operative serum creatinine, pre-operative RBC count <3.31 T/L, aortic cross-clamp time >140 min, intraoperative lactic acid level, the transfusion of WRBC, atrial fibrillation within post-operative 24 h. The risk model was validated by internal sets. The model showed a robust discrimination, with an area under the receiver operating characteristic (ROC) curve of 0.718. The calibration plots for the probability of perioperative ischemic liver injury showed coherence between the predictive probability and the actual probability (Hosmer-Lemeshow test, P = 0.637). In the validation cohort, the nomogram still revealed good discrimination (C statistic = 0.727) and good calibration (Hosmer-Lemeshow test, P = 0.872). The 10-fold cross-validation of the nomogram showed that the average misdiagnosis rate was 9.95% and the lowest misdiagnosis rate was 9.81%. Conclusion: Our risk model can be used to predict the probability of ILI after AAD surgery and have the potential to assist clinicians in making treatment recommendations.

Development of a Rab9 transgenic mouse and its ability to increase the lifespan of a murine model of Niemann-Pick type C disease.

Niemann-Pick, type C (NP-C) disease is an autosomal recessive neurovisceral storage disorder in which cholesterol and sphingolipids accumulate. There is no specific treatment for this disease, which is characterized by progressive neurological deterioration, sometimes accompanied by hepatosplenomegaly. We and others have shown that overexpression of certain Rab GTPases corrects defective membrane trafficking and reduces lipid storage in cultured NP-C fibroblasts. Here, we tested the possibility that Rab protein overexpression might also have beneficial effects in vivo using a murine model of NP-C. We first generated several lines of transgenic mice that ubiquitously overexpress Rab9 up to approximately 30-fold more than endogenous levels and found that the transgene expression had no obvious effects on fertility, behavior, or lifespan in normal mice. These transgenic strains were then crossed with NP-C mutant mice to produce NP-C homozygous recessive mice with and without the Rab9 transgene. Life expectancy of the NPC1 homozygous recessive animals was extended up to 22% depending on gender and the transgenic strain that was used. Histological studies and lipid analysis of brain sections indicated that the NP-C mice carrying the Rab9 transgene had dramatically reduced storage of GM(2) and GM(3) gangliosides relative to NP-C animals lacking the transgene. These results demonstrate that Rab9 overexpression has the potential to reduce stored lipids and prolong lifespan in vivo.

Proteomic identification of proteins translocated to membrane microdomains upon treatment of fibroblasts with the glycosphingolipid, C8-beta-D-lactosylceramide.

Plasma membrane (PM) microdomains, including caveolae and other cholesterol-enriched subcompartments, are involved in the regulation of many cellular processes, including endocytosis, attachment and signaling. We recently reported that brief incubation of human skin fibroblasts with the synthetic glycosphingolipid, D-erythro-octanoyl-lactosylceramide (C8-D-e-LacCer), stimulates endocytosis via caveolae and induces the appearance of micron-size microdomains on the PM. To further understand the effects of C8-D-e-LacCer treatment on PM microdomains, we used a detergent-free method to isolate microdomain-enriched membranes from fibroblasts treated +/-C8-D-e-LacCer, and performed 2-DE and mass spectrophotometry to identify proteins that were altered in their distribution in microdomains. Several proteins were identified in the microdomain-enriched fractions, including lipid transfer proteins and proteins related to the functions of small GTPases. One protein, Rho-associated protein kinase 2 (ROCK2), was verified by Western blotting to occur in microdomain fractions and to increase in these fractions after D-e-LacCer treatment. Immunofluorescence revealed that ROCK2 exhibited an increased localization at or near the PM in C8-D-e-LacCer-treated cells. In contrast, ROCK2 distribution in microdomains was decreased by treatment of cells with C8-L-threo-lactosylceramide, a glycosphingolipid with non-natural stereochemistry. This study identifies new microdomain-associated proteins and provides evidence that microdomains play a role in the regulation of the Rho/ROCK signaling pathway.

Cholesterol loading increases the translocation of ATP synthase beta chain into membrane caveolae in vascular endothelial cells.

Caveolae and its structural protein caveolin-1 (Cav-1) are abundant in vascular endothelial cells (ECs) and have been suggested to contribute to cell signaling and cholesterol trafficking. This study investigated the effect of cholesterol on the movement of caveolae-related proteins in human umbilical vein ECs with use of caveolae functional proteomics. After cholesterol exposure to ECs for 2 to 4 h, caveolae were isolated and separated on 2-D protein gels. Among 40 protein spots revealed in caveolae fractions, the ATP synthase beta subunit (ATPS-beta), one of the 3 proteins enriched by cholesterol in caveolae, was confirmed by western blotting and confocal microscopy. Further, cholesterol exposure increased the level of ATPS-beta, along with Cav-1 and cholesterol in caveolae. These effects could be blocked by cytochalasin B, an actin cytoskeleton disruptor. ATPS-beta was physically associated with Cav-1, as demonstrated by co-immunoprecipitation and GST-Cav-1 fusion protein pull-down assay. Cholesterol increased the extracellular ATP release mediated by ATPS-beta, since this action could be blocked by piceatannol or oligomycin, ATPS inhibitors. Thus, the ectopic localization of ATPS-beta may participate in the energy balance of cells in response to the change in intracellular cholesterol levels.

Calcitonin gene-related peptide inhibits interleukin-1beta-induced interleukin-8 secretion in human type II alveolar epithelial cells.

AIM: Our previous data have shown that type II alveolar epithelial (AEII) cells express neuropeptide calcitonin gene-related peptide (CGRP), and that pro-inflammatory factor interleukin1-beta (IL-1beta) induces CGRP secretion in the A549 human AEII cell line. In the present study, we investigated the effect of endogenous and exogenous CGRP on IL-1beta-induced chemokine interleukin-8 (IL-8) secretion. METHODS: We used enzyme-linked immunosorbent assay (ELISA) and RT-PCR to detect IL-8 protein and mRNA levels, respectively. siRNA and the stably transfected cell line were used to knock down and overexpress the CGRP gene, respectively, and chemiluminescence assay was used to detect reactive oxygen species (ROS) formation. RESULTS: CGRP-1 receptor antagonist hCGRP8-37 (0.1-1 nmol/L) greatly amplified IL-1beta-induced IL-8 production. The inhibition of CGRP expression by siRNA significantly increased IL-8 secretion upon IL-1beta stimulation. However, cell clones stably transfected with CGRP showed significantly inhibited mRNA and protein levels of IL-8 induced by IL-1beta. CONCLUSION: These data imply that AEII cell-derived CGRP suppress IL-1beta-induced IL-8 secretion in an autocrine/paracrine mode. Further investigation showed that CGRP attenuated IL-1beta-aroused ROS formation, which is an early indication of pro-inflammatory factor signaling.

Calcitonin gene-related peptide inhibits interleukin-1beta-induced endogenous monocyte chemoattractant protein-1 secretion in type II alveolar epithelial cells.

As important multifunctional cells in the lung, alveolar epithelial type II (AEII) cells secrete numerous chemokines on various stimuli. Our previous data showed that AEII cells also express the neuropeptide calcitonin gene-related peptide (CGRP) and the proinflammatory factor interleukin (IL)-1beta induces CGRP secretion in the A549 human AEII cell line. In the present study, the CGRP-1 receptor antagonist human (h)CGRP(8-37) (0.1-1 nM) greatly amplified the production of IL-1beta-induced monocyte chemoattractant protein (MCP)-1. The inhibition of CGRP expression by small interfering RNA significantly increased MCP-1 secretion on IL-1beta stimulation. However, exogenous hCGRP (10-100 nM) suppressed IL-1beta-evoked MCP-1 secretion in MCP-1 promoter activity, and CGRP gene stably transfected cell clones significantly inhibited both the mRNA and protein levels of MCP-1 induced by IL-1beta. These data imply that AEII-derived CGRP suppressed IL-1beta-induced MCP-1 secretion in an autocrine/paracrine mode. Subsequent investigation revealed that CGRP inhibited IL-1beta-evoked NF-kappaB activity by suppressing IkappaBalpha phosphorylation and degradation. Moreover, CGRP attenuated IL-1beta-induced reactive oxygen species (ROS) formation, the early event in proinflammatory factor signaling. We previously showed that the CGRP inhibitory effect was mediated by elevated intracellular cAMP and show here that analogs of cAMP, 8-bromoadenosine 3',5'-cyclic monophosphothioate and the Sp isomer of adenosine 3',5'-cyclic monophosphothioate, mimicked the CGRP suppressive effect on IL-1beta-induced ROS formation, NF-kappaB activation, and MCP-1 secretion. Thus increased endogenous CGRP secretion in lung inflammatory disease might eliminate the excessive response by elevating the cAMP level through inhibiting the ROS-NF-kappaB-MCP-1 pathway.

Endogenous calcitonin gene-related peptide protects human alveolar epithelial cells through protein kinase Cepsilon and heat shock protein.

The intracellular mechanisms of ischemic preconditioning (PC) in preventing lung dysfunction following transplantation, shock, and trauma remain poorly understood. Previously, we have shown that alveolar epithelial cells secrete calcitonin gene-related peptide (CGRP) under inflammatory stress. Using a hypoxia/reoxygenation (H/R) and PC model, we found that CGRP was also secreted from human type II alveolar epithelial cells (A549) after PC. The locally released CGRP interacted with its receptor on the membrane of A549 cells and elicited downstream signals mediating the PC effect, because hCGRP(8-37), a specific CGRP receptor antagonist, attenuated the protective effect of PC. Pre-inhibition of CGRP protein synthesis by small interfering RNA exacerbated (but overexpression of the CGRP gene ameliorated) H/R-induced cell death, which supports the autocrine effect of CGRP on A549 cells. Exogenous bioactive CGRP mimicked the beneficial effect of PC and up-regulated the expression of heat shock protein 70 (HSP70), which might act as the end effector to maintain cell viability. These effects were sensitive to hCGRP(8-37), calphostin C (a protein kinase C (PKC) inhibitor), and 5-hydroxydecanoic acid (a mitochondrial K(+)(ATP) channel blocker) but were insensitive to protein kinase A blockers. Moreover, CGRP induced the membrane translocation of PKCepsilon. PKCV1-2 (a cell-permeable inhibitory peptide of PKCepsilon) effectively abolished CGRP-induced HSP70 expression and cell protection. Therefore, PC induces CGRP secretion from human alveolar epithelial cells, and the locally released CGRP acts back on these cells, protecting them from H/R injury. The post-receptor signaling of CGRP is through PKCepsilon-dependent expression of HSP70.