High-affinity binding sites for heparin generated on leukocytes during apoptosis arise from nuclear structures segregated during cell death

During cell death of human cultured leukocytes (Jurkat, HL-60, THP-1, U937) and freshly prepared leukocytes, we observed a greater than 100-fold increase in the affinity of apoptotic and necrotic cells for fluorescein isothiocyanate (FITC)-heparin in comparison with live cells. Binding of FITC-heparin was reversed in the presence of high ionic strength, unlabeled heparan sulfate, and heparin and pentosan polysulfate, but not in the presence of chondroitin and dermatan sulfates. During the course of cell death, the increase in the percentage of cells positive for annexin V binding correlated with the increase in the population positive for binding FITC-heparin. Confocal microscopy demonstrated that heparin binding to dead cells was restricted to 1 or 2 small domains on the surfaces of apoptotic cells and to larger, but still discrete, areas that did not localize with chromatin on ruptured necrotic cells. The heparin-binding domains originated from the nucleus and may correspond to the ribonucleoprotein-containing structures that have recently been shown to segregate within the nucleus of cells and to move onto the cell membrane. We observed that phagocytosis of dead Jurkat cells by monocyte-derived macrophages was blocked when the heparin-binding capacity of the dead cells was saturated by the addition of pentosan polysulfate. From this we concluded that the ability of dead cells to bind to heparan sulfate proteoglycans on the surfaces of macrophages may assist in phagocytic clearance.     

Lower relapse rates with good post-transplant outcome in alcoholic liver disease: Experience from a living donor liver transplant center

Introduction

Post-transplant relapse is a major factor influencing the long-term outcome in alcoholic liver disease (ALD) patients.

Aims

The aim of this study was to evaluate the relapse rates following living donor liver transplantation (LDLT) in patients with ALD in the Indian context with strong family support.

Methods

Of 458 patients who underwent LDLT for ALD, 408 were included in the study. Post-transplant relapse was determined by information provided by the patient and/or family by means of outpatient and e-mail questionnaire, supported by clinical/biochemical parameters/liver histopathology.

Results

All except one were males, with a mean age of 46.9?±?8.5 years. The overall rate of relapse was 9.5 % at 34.7 months (interquartile range (IQR) 15–57.6), lower than that reported in the literature from the West. The relapse rate was higher in patients with a shorter duration of pre-transplant abstinence (17.4 % and 15.4 % for recipients with pre-transplant abstinence of <3 and <6 months, respectively, p?<?0.05). The overall survival was 88.5 % at 3 years. Of 39 patients with relapse, 16 (41 %) were occasional drinkers, 14 (35.8 %) were moderate drinkers, and 9 (23 %) were heavy drinkers. All the heavy drinkers presented with features of graft dysfunction.

Conclusions

Good results can be obtained following LDLT for ALD, with significantly lower relapse rates in our setup as compared to the West.

     

Neutralization of Heparin in Plasma by Platelet Factor 4 and Protamine Sulphate

The neutralization of heparin by protamine sulphate and platelet factor 4 (PF₄) has been studied using kaolin cephalin clotting time (KCCT), thrombin clotting time (TCT) and anti-Xa assays to measure residual heparin levels. Protamine sulphate and purified PF₄ had almost equivalent neutralizing ability on a weight basis regardless of which assay system was used. Plasma samples that were heparinized in vitro could be totally and readily neutralized by both agents in all of the assay systems used. However, when heparinized plasma samples were obtained following intravenous injection of the drug different results for neutralization were obtained depending on the heparin assay used. When residual heparin was measured by anti-Xa assay partial neutralization of heparin was observed even in the presence of a large excess of neutralizing agent. The same in vivo derived heparinized plasma samples had no heparin activity following neutralization if residual heparin was measured by KCCT and TCT assays. Further ion exchange chromatography experiments demonstrated that the heparin-like activity that could not be neutralized in the anti-Xa assay was not adsorbed by the resin ECTEOLA-cellulose, and therefore could not be removed from plasma by this technique. These results suggest, therefore, that part of the plasma anti-Xa activity produced following intravenous injection of heparin differs from the anti-Xa activity obtained following addition of the drug to plasma in vitro .     

Time to consider a STEMI sleepover?: Measuring the “value” of an in‐house STEMI team

• This study demonstrates that the presence of an in‐hospital STEMI team significantly reduces D2B times
• PCI centers should consider the “value” (outcomes relative to cost) of an in‐house STEMI team
• Larger studies are required to assess the cost effectiveness and clinical effectiveness attributable to an in‐house STEMI team

     

From the Cover: Myocardial pressure overload induces systemic inflammation through endothelial cell IL-33

Hypertension increases the pressure load on the heart and is associated with a poorly understood chronic systemic inflammatory state. Interleukin 33 (IL-33) binds to membrane-bound ST2 (ST2L) and has antihypertrophic and antifibrotic effects in the myocardium. In contrast, soluble ST2 appears to act as a decoy receptor for IL-33, blocking myocardial and vascular benefits, and is a prognostic biomarker in patients with cardiovascular diseases. Here we report that a highly local intramyocardial IL-33/ST2 conversation regulates the heart’s response to pressure overload. Either endothelial-specific deletion of IL33 or cardiomyocyte-specific deletion of ST2 exacerbated cardiac hypertrophy with pressure overload. Furthermore, pressure overload induced systemic circulating IL-33 as well as systemic circulating IL-13 and TGF-beta1; this was abolished by endothelial-specific deletion of IL33 but not by cardiomyocyte-specific deletion of IL33. Our study reveals that endothelial cell secretion of IL-33 is crucial for translating myocardial pressure overload into a selective systemic inflammatory response.Hypertension is the most common cardiovascular risk factor and contributes to widespread morbidity and mortality worldwide (1), but the pathological and molecular mechanisms by which elevated blood pressure promotes vascular disease remain uncertain. Inflammation has been hypothesized to play a role in hypertension as well as the progression of vascular disease (2, 3). Although the association between hypertension and inflammation has now been clearly demonstrated, molecular mechanisms that link hypertension to systemic inflammation are unclear.The soluble receptor ST2 is a prognostic biomarker in patients with cardiovascular disease (4, 5), and serum ST2 levels also predict changes in blood pressure in the community (6). ST2, also known as IL1RL1 (IL-1 receptor like 1), is a member of the IL-1 receptor family, which plays a major role in immune and inflammatory responses (7). At least two forms of ST2 are known, including the transmembrane receptor (ST2L) and the soluble form (sST2) that circulates in blood (8). Membrane-bound ST2L interacts with IL-33, an IL-1 family ligand (9), and IL-33 can have antihypertrophic and antifibrotic effects in the myocardium (10). In contrast, sST2 appears to act as a decoy receptor for IL-33, blocking myocardial and vascular benefits (10–12). IL-33 is also expressed in endothelial cells (ECs) (13–16), in which it induces angiogenesis (17), expression of adhesion molecules, and inflammatory activation (18). Here we report the surprising finding that endothelial IL-33 from pressure overload induces a selective systemic response, potentially linking hypertension with circulating factors that can affect the vasculature and other organs.     

Etomidate: to use or not to use for endotracheal intubation in the critically ill?

Endotracheal intubation is frequently performed in the intensive care unit (ICU). It can be life-saving for many patients who present with acute respiratory distress. However, it is equally associated with complications that may lead to unwanted effects in this patient population. According to the literature, the rate of complications associated with endotracheal intubation is much higher in an environment such as the ICU as compared to other, more controlled environments (i.e., operating room). Thus, the conduct of performing such a procedure needs to be accomplished with the utmost care. To facilitate establishment of the breathing tube, sedation is routinely administered. Given the tenuous hemodynamic status of the critically ill, etomidate was frequently chosen to blunt further decreases in blood pressure and/or heart rate. Recently however, reports have demonstrated a possible association with the use of etomidate for endotracheal intubation and mortality in the critically ill. In addition, this association seems to be predominantly in patients diagnosed with sepsis. As a result, some have advocated against the use of this medication in septic patients. Due to the negative associations identified with etomidate and mortality, several investigators have evaluated potential alternatives to this solution (e.g., ketamine and ketamine-propofol admixture). These studies have shown promise. However, despite the evidence against using etomidate for endotracheal intubation, other studies have demonstrated no such association. This leaves the critical care clinician with uncertainty regarding the best sedative to administer in this patient population. The following editorial discusses current evidence regarding etomidate use for endotracheal intubation and mortality. In particular, we highlight a recent article with the largest population to date that found no association between etomidate and mortality in the critically ill and illustrate important findings that the reader should be aware of regarding this article.     

A case series of third-trimester raltegravir initiation: Impact on maternal HIV-1 viral load and obstetrical outcomes

OBJECTIVE:

To describe the impact of initiating raltegravir (RAL)-containing combination antiretroviral therapy (cART) regimens on HIV viral load (VL) in pregnant women who have high or suboptimal VL suppression late in pregnancy.

METHODS:

HIV-infected pregnant women who started RAL-containing cART after 28 weeks’ gestation from 2007 to 2013 were identified in two university hospital centres.

RESULTS AND DISCUSSION:

Eleven HIV-infected women started RAL at a median gestational age of 35.7 weeks (range 31.1 to 38.0 weeks). Indications for RAL initiation were late presentation in pregnancy (n=4) and suboptimal VL suppression secondary to poor adherence or viral resistance (n=7). Mean VL at the time of RAL initiation was 73,959 copies/mL (range <40 to 523,975 copies/mL). Patients received RAL for a median of 20 days (range one to 71 days). The mean decline in VL from the time of RAL initiation to delivery was 1.93 log, excluding one patient who received only one RAL dose and one patient with undetectable VL at the time of RAL initiation. After eight days on RAL, 50% of the women achieved a VL <1000 copies/mL (the threshold for recommended Caesarean section to reduce the risk for perinatal transmission). There were no cases of perinatal HIV transmission.

CONCLUSION:

The present study provides preliminary data to support the use of RAL-containing cART to expedite HIV-1 VL reduction in women who have a high VL or suboptimal VL suppression late in pregnancy, and to decrease the risk of HIV perinatal transmission while avoiding Caesarean section. Further assessment of RAL safety during pregnancy is warranted.