Ex Vivo Effect of Varespladib on Secretory Phospholipase A2 Alveolar Activity in Infants with ARDS

Background

Secretory phospholipase A2 (sPLA2) plays a pivotal role in acute respiratory distress syndrome (ARDS). This enzyme seems an interesting target to reduce surfactant catabolism and lung tissue inflammation. Varespladib is a specifically designed indolic sPLA2 inhibitor, which has shown promising results in animals and adults. No specific data in pediatric ARDS patients are yet available.

Methods

We studied varespladib in broncho-alveolar lavage (BAL) fluids obtained ex vivo from pediatric ARDS patients. Clinical data and worst gas exchange values during the ARDS course were recorded. Samples were treated with saline or 10–40–100 µM varespladib and incubated at 37°C. Total sPLA2 activity was measured by non-radioactive method. BAL samples were subjected to western blotting to identify the main sPLA isotypes with different sensitivity to varespladib. Results was corrected for lavage dilution using the serum-to-BAL urea ratio and for varespladib absorbance.

Results

Varespladib reduces sPLA2 activity (p<0.0001) at 10,40 and 100 µM; both sPLA2 activity reduction and its ratio to total proteins significantly raise with increasing varespladib concentrations (p<0.001). IC₅₀ was 80 µM. Western blotting revealed the presence of sPLA2-IIA and –IB isotypes in BAL samples. Significant correlations exist between the sPLA2 activity reduction/proteins ratio and PaO₂ (rho = 0.63;p<0.001), PaO₂/FiO₂ (rho = 0.7; p<0.001), oxygenation (rho = −0.6; p<0.001) and ventilation (rho = −0.4;p = 0.038) indexes.

Conclusions

Varespladib significantly inhibits sPLA2 in BAL of infants affected by post-neonatal ARDS. Inhibition seems to be inversely related to the severity of gas exchange impairment.     

Apoptosis-resistant phenotype in HL-60-derived cells HCW-2 is related to changes in expression of stress-induced proteins that impact on redox status and mitochondrial metabolism

The onset of resistance to drug-induced apoptosis of tumour cells is a major problem in cancer therapy. We studied a drug-selected clone of promyelocytic HL-60 cells, called HCW-2, which display a complex resistance to a wide variety of apoptosis-inducing agents and we found that these cells show a dramatic increase in the expression of heat shock proteins (Hsps) 70 and 27, while the parental cell line does not. It is known that stress proteins such as Hsps can confer resistance to a variety of damaging agents other than heat shock, such as TNF-alpha, monocyte-induced cytotoxicity, and also play a role in resistance to chemotherapy. This elevated expression of Hsps is paralleled by an increased activity of mitochondrial metabolism and pentose phosphate pathway, this latter leading to high levels of glucose-6-phosphate dehydrogenase and, consequently, of glutathione. Thus, the apoptotic-deficient phenotype is likely because of the presence of high levels of stress response proteins and GSH, which may confer resistance to apoptotic agents, including chemotherapy drugs. Moreover, the fact that in HCW-2 cells Hsp70 are mainly localised in mitochondria may account for the increased performances of mitochondrial metabolism. These observations could have some implications for the therapy of cancer, and for the design of combined strategies that act on antioxidant defences of the neoplastic cell.     

Genetic polymorphisms of Fas (CD95) and FasL (CD178) in human longevity: studies on centenarians

Apoptosis plays a crucial role in immunosenescence, as also evidenced by the increased expression of Fas in lymphocytes from aged people. However, little is known about the genetic regulation of Fas and its ligand, FasL. We have studied their polymorphisms in 50 centenarians and 86 young donors living in Northern Italy. The first Fas polymorphism, at position -670, has in Caucasian a heterozigosity of 51%; the second, at -1377 position, has the wild type allele (G) with a very high frequency (83%) respect to the mutant allele. Genotype and allele distribution for both polymorphisms were similar in controls and centenarians. Similar results were found as far as two FasL polymorphisms (IVS2nt-124 and IVS3nt169) are concerned. On the whole, our data suggest that Fas and FasL polymorphisms, as well as their haplotypes, are unlikely to be associated with successful human longevity.     

Changes in intramitochondrial cardiolipin distribution in apoptosis-resistant HCW-2 cells, derived from the human promyelocytic leukemia HL-60

Using a cytofluorimetric approach, we studied intramitochondrial cardiolipin (CL) distribution in HCW-2 cells, an apoptosis-resistant clone of human HL-60 cells. In HL-60, about 50% of total CL is distributed in the outer leaflet of mitochondrial inner membrane, while in HCW-2 a significantly higher amount of CL (about 65%) is in that site. In basal conditions, HSW-2 cells also show a reduced mitochondrial membrane potential even if they are able to proliferate as the parental line. Taking into account the complex functions that CL plays in the regulation of mitochondrial activity, it is likely that HCW-2 could produce ATP utilizing more glycolytic pathways rather than mitochondrial respiratory chain.     

Mitochondrial heterogeneity during staurosporine-induced apoptosis in HL60 cells: analysis at the single cell and single organelle level

BACKGROUND: Apoptosis is a complex phenomenon during which several events occur. A growing interest exists on the role and functionality of mitochondria during this type of cell death. The responsibility of modifications in mitochondrial membrane potential (Delta Psi) in triggering apoptosis is under investigation. METHODS: We evaluated Delta Psi changes in HL60 cells treated with staurosporine (STS). Flow cytometry and confocal microscopy have been used to analyze samples stained with two Delta Psi-sensitive probes, JC-1 and MitoTrackertrade mark Red CMXRos. RESULTS: At the cellular level, we found heterogeneic behavior. Indeed, after STS treatment, some cells displayed typical markers of apoptosis and a collapse in Delta Psi. Others were apoptotic with no changes in Delta Psi, others changed Delta Psi without being apoptotic, and others were healthy. The same heterogeneic response to STS was found at the single organelle level. In a given cell, some mitochondria were depolarized whereas others were not. CONCLUSION: In this model of apoptosis, changes in Delta Psi can be different among cells of the same type and among different organelles of the same cell. The collapse in Delta Psi is thus a heterogeneic phenomenon that seems to be an ancillary event following the irreversible phase of the apoptotic process.     

Evaluation of DRB1 high resolution typing by a new SSO-based Luminex method

HLA testing is an essential part of the process to identify a donor who may be a good match for the patients who need haematopoietic stem cells from bone marrow, peripheral blood or cord blood and the DNA typing in high resolution is now recommended as the Scientific Societies also describe in their standards. Recently the new PCR-Luminex HLA typing method, based on the reverse sequence specific oligonucleotide probes coupled with a microsphere beads in an array platform, has been well established. We report the data from 146 samples previously typed to a four digits level and used to evaluate the accuracy, sensitivity and performance of the new high definition DRB1 by PCR-Luminex kit. One hundred and forty-six samples from unrelated healthy donors, haematological patients or external proficiency tests were used in this study. The Luminex high definition DRB1 typing represents a versatile method and may be easily introduced in the routine, particularly when the technical team has already acquired experience on the technique. Only few HLA allelic combinations need an additional typing by PCR–SSP or SBT to solve the ambiguous results thus reducing the time necessary to produce a final report.     

Metabolic response of yellow mealworm larvae to two alternative rearing substrates

Introduction

Bitter melon (Momordica charantia, Cucurbitaceae) is a popular edible medicinal plant, which has been used as a botanical dietary supplement for the treatment of diabetes and obesity in Chinese folk medicine. Previously, our team has proved that cucurbitanes triterpenoid were involved in bitter melon’s anti-diabetic effects as well as on increasing energy expenditure. The triterpenoids composition can however be influenced by changes of varieties or habitats.

Objectives

To clarify the significance of bioactive metabolites diversity among different bitter melons and to provide a guideline for selection of bitter melon varieties, an exploratory study was carried out using a UHPLC-HRMS based metabolomic study to identify chemotypes.

Methods

Metabolites of 55 seed samples of bitter melon collected in different parts of China were profiled by UHPLC-HRMS. The profiling data were analysed with multivariate (MVA) statistical methods. Principle component analysis (PCA) and hierarchical cluster analysis (HCA) were applied for sample differentiation. Marker compounds were identified by comparing spectroscopic data with isolated compounds, and additional triterpenes were putatively identified by propagating annotations through a molecular network (MN) generated from UHPLC-HRMS & MS/MS metabolite profiling.

Results

PCA and HCA provided a good discrimination between bitter melon samples from various origins in China. This study revealed for the first time the existence of two chemotypes of bitter melon. Marker compounds of those two chemotypes were identified at different MSI levels. The combined results of MN and MVA demonstrated that the two chemotypes mainly differ in their richness in cucurbitane versus oleanane triterpenoid glycosides (CTGs vs. OTGs).

Conclusion

Our finding revealed a clear chemotype distribution of bioactive components across bitter melon varieties. While bioactivities of individual CTGs and OTGs still need to be investigated in more depth, our results could help in future the selection of bitter melon varieties with optimised metabolites profile for an improved management of diabetes with this popular edible Chinese folk medicine.

     

Summary of the 2000 Surgeon General's Listening Session: Toward a National Action Plan on Overweight and Obesity

Objective: To provide insight into discussions at the Surgeon General's Listening Session, “Toward a National Action Plan on Overweight and Obesity,” and to complement The Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity. Research Methods and Procedures: On December 7 and 8, 2000, representatives from federal, state, academic, and private sectors attended the Surgeon General's Listening Session and were given an opportunity to recommend what to include in a national plan to address overweight and obesity. The public was invited to comment during a corresponding public comment period. The Surgeon General's Listening Session was also broadcast on the Internet, allowing others to view the deliberations live or access the archived files. Significant discussion points from the Listening Session have been reviewed by representatives of the federal agencies and are the basis of this complementary document. Results: Examples of issues, strategies, and barriers to change are discussed within five thematic areas: schools, health care, family and community, worksite, and media. Suggested cooperative or collaborative actions for preventing and decreasing overweight and obesity are described. An annotated list of some programmatic partnerships is included. Discussion: The Surgeon General's Listening Session provided an opportunity for representatives from family and community groups, schools, the media, the health-care environment, and worksites to become partners and to unite around the common goal of preventing and decreasing overweight and obesity. The combination of approaches from these perspectives offers a rich resource of opportunity to combat the public health epidemic of overweight and obesity.