Placental trophoblast-derived factors diminish endothelial barrier function

Although increased vascular permeability is an important event in the pathogenesis of preeclampsia, the origin of the circulating factor(s) that elicits this endothelial barrier dysfunction is not known. In this study, we use coculture of endothelial cells and placental trophoblast cells to determine whether placental trophoblasts are a potential source of the factor(s) that mediate the increased vascular permeability of preeclampsia. Human umbilical vein endothelial cells grown in Transwell inserts or on coverslips were cocultured with trophoblast cells isolated from normal and preeclamptic placentas or placenta conditioned media. Endothelial cell barrier function was determined by: 1). measurements of electrical resistance and leakage of horseradish peroxidase, and 2). immunofluorescent staining of vascular endothelial-cadherin, pan-cadherin, and occludin. Uterine myometrium endothelial cells were also studied for comparison. We observed the following: 1). electrical resistance was significantly (P < 0.01) decreased (compared with control endothelial cells) in endothelial cell monolayers cocultured with normal trophoblast cells and further reduced in endothelial cells cocultured with preeclamptic trophoblast cells; 2). an increased horseradish peroxidase leakage that was correlated with the decreased electrical resistance in cocultured cells; and 3). disorganized tight junction proteins and an altered distribution of vascular endothelial-cadherin and occludin in monolayers of endothelial cells cocultured with preeclamptic trophoblast cells. Similar responses were noted in uterine myometrium endothelial cells. We conclude that: 1). placental trophoblast cells produce factors that diminish the barrier function of endothelial cells; 2). endothelial tight junctions are more susceptible to factors released from preeclamptic trophoblast cells than from normal trophoblast cells; and 3). these results implicate trophoblast-derived factors in the increased vascular permeability associated with preeclampsia.     

18F‐Fluorodeoxyglucose (FDG)‐PET features of focal nodular hyperplasia (FNH) of the liver

Abstract: Aim: The aim of this paper is to describe the imaging pattern of focal nodular hyperplasia (FNH) by ¹⁸F‐fluorodeoxyglucose (18F‐FDG) positron emission tomography (PET). Methods: Eight consecutive asymptomatic patients with histologic proof of FNH underwent 18F‐FDG PET imaging. The lesions were found incidentally. The 18F‐FDG PET imaging was performed with a dedicated PET tomograph after intravenous injection of 300–370 MBq 18F‐FDG. The 18F‐FDG accumulation in the lesions was (semi)quantified by calculating the standardized uptake value (SUV) and SUV has been corrected for the lean body mass (LBM). Eight patients with liver metastases spread from melanoma (n=2) and colorectal carcinoma (n=6) served as controls. The size of the FNH lesions and of the control group ranged from 2.0 to 8.5 cm (mean 4.83 cm±2.37) and from 1.5 to 6 cm (mean 3.28±1.52), respectively. Results: While in malignant liver lesions the accumulation of 18F‐FDG was significantly increased, all FNH lesions showed normal or even decreased accumulation of 18F‐FDG. In FNH lesions, SUV ranged between 1.5 and 2.6 (mean 2.12±0.38), whereas all liver metastases showed an increased SUV ranging between 6.20 and 16.00 (mean 10.07±3.79). The SUV corrected for LMB (SUV_LBM) was similar to the SUV and ranged between 0.9 and 2.2 (mean 1.81±0.41) for FNH and between 5.9 and 16.3 (mean 9.15±4.03), respectively. Conclusion: In contrast to liver metastases, there is no increased glucose metabolism in FNH in vivo. The imaging feature of FNH by 18F‐FDG‐PET imaging is not specific for FNH; however, it may be helpful to differentiate FNH from liver metastases in cancer patients if radiological methods are not diagnostic.     

Analytical profile of N‐ethyl‐N‐cyclopropyl lysergamide (ECPLA), an isomer of lysergic acid 2,4‐dimethylazetidide (LSZ)

Recent investigations have shown that N‐ethyl‐N‐cyclopropyl lysergamide (ECPLA) produces LSD‐like behavioral effects in mice, which suggests that it may act as a hallucinogen in humans. Although the use of ECPLA as a recreational drug has been limited, key analytical data that can be used to detect ECPLA are required for future forensic and clinical investigations. ECPLA is an isomer of (2′S,4′S)‐lysergic acid 2,4‐dimethylazetidide (LSZ), a lysergamide that emerged as a recreational drug in 2013. Several analytical approaches were examined, including single‐ and tandem mass spectrometry platforms at low and high resolution, gas‐ and liquid chromatography (GC, LC), nuclear magnetic resonance spectroscopy (NMR), and GC condensed‐phase infrared spectroscopy (GC‐sIR). ECPLA and LSZ could be differentiated by NMR, GC‐sIR, GC, and LC‐based methods. The electron ionization mass spectra of ECPLA and LSZ contained ion clusters typically observed with related lysergamides such as m/z 150–155, m/z 177–182, m/z 191–197, m/z 205–208, and m/z 219–224. One of the significant differences in abundance related to these clusters included ions at m/z 196 and m/z 207/208. The base peaks were detected at m/z 221 in both cases followed by the retro‐Diels‐Alder fragment at m/z 292. Minor but noticeable differences between the two isomers could also be seen in the relative abundance of m/z 98 and m/z 41. Electrospray ionization mass spectra included lysergamide‐related ions at m/z 281, 251, 223, 208, 197, 180, and 140. LSZ (but not ECPLA) showed product ions at m/z 267 and m/z 98 under the conditions used.     

Return of the lysergamides. Part VI: Analytical and behavioural characterization of 1‐cyclopropanoyl‐d‐lysergic acid diethylamide (1CP‐LSD)

Lysergic acid diethylamide (LSD) is a prototypical serotonergic psychedelic drug and the subject of many clinical investigations. In recent years, a range of lysergamides has emerged with the production of some being inspired by the existing scientific literature. Others, for example various 1‐acyl substituted lysergamides, did not exist before their appearance as research chemicals. 1‐Cylopropanoyl‐LSD (1CP‐LSD) has recently emerged as a new addition to the group of lysergamide‐based designer drugs and is believed to be psychoactive in humans. In this investigation, 1CP‐LSD was subjected to detailed analytical characterizations including various mass spectrometry (MS) platforms, gas and liquid chromatography, nuclear magnetic resonance spectroscopy, solid phase and GC condensed phase infrared spectroscopy. Analysis by GC–MS also revealed the detection of artificially induced degradation products. Incubation of 1CP‐LSD with human serum led to the formation of LSD, indicating that it may act as a prodrug for LSD in vivo, similar to other 1‐acyl substituted lysergamides. The analysis of blotters and pellets is also included. 1CP‐LSD also induces the head‐twitch response (HTR) in C57BL/6 J mice, indicating that it produces an LSD‐like behavioural profile. 1CP‐LSD induced the HTR with an ED₅₀ = 430.0 nmol/kg which was comparable to 1P‐LSD (ED₅₀ = 349.6 nmol/kg) investigated previously. Clinical studies are required to determine the potency and profile of the effects produced by 1CP‐LSD in humans.     

Cx43 hemichannel microdomain signaling at the intercalated disc enhances cardiac excitability

Cx43, a major cardiac connexin, forms precursor hemichannels that accrue at the intercalated disc to assemble as gap junctions. While gap junctions are crucial for electrical conduction in the heart, little is known about the potential roles of hemichannels. Recent evidence suggests that inhibiting Cx43 hemichannel opening with Gap19 has antiarrhythmic effects. Here, we used multiple electrophysiology, imaging, and super-resolution techniques to understand and define the conditions underlying Cx43 hemichannel activation in ventricular cardiomyocytes, their contribution to diastolic Ca²⁺ release from the sarcoplasmic reticulum, and their impact on electrical stability. We showed that Cx43 hemichannels were activated during diastolic Ca²⁺ release in single ventricular cardiomyocytes and cardiomyocyte cell pairs from mice and pigs. This activation involved Cx43 hemichannel Ca²⁺ entry and coupling to Ca²⁺ release microdomains at the intercalated disc, resulting in enhanced Ca²⁺ dynamics. Hemichannel opening furthermore contributed to delayed afterdepolarizations and triggered action potentials. In single cardiomyocytes, cardiomyocyte cell pairs, and arterially perfused tissue wedges from failing human hearts, increased hemichannel activity contributed to electrical instability compared with nonfailing rejected donor hearts. We conclude that microdomain coupling between Cx43 hemichannels and Ca²⁺ release is a potentially novel, targetable mechanism of cardiac arrhythmogenesis in heart failure.     

The Effect of Standard Versus Longer Intestinal Bypass on GLP-1 Regulation and Glucose Metabolism in Patients With Type 2 Diabetes Undergoing Roux-en-Y Gastric Bypass: The Long-Limb Study

OBJECTIVERoux-en-Y gastric bypass (RYGB) characteristically enhances postprandial levels of glucagon-like peptide 1 (GLP-1), a mechanism that contributes to its profound glucose-lowering effects. This enhancement is thought to be triggered by bypass of food to the distal small intestine with higher densities of neuroendocrine L-cells. We hypothesized that if this is the predominant mechanism behind the enhanced secretion of GLP-1, a longer intestinal bypass would potentiate the postprandial peak in GLP-1, translating into higher insulin secretion and, thus, additional improvements in glucose tolerance. To investigate this, we conducted a mechanistic study comparing two variants of RYGB that differ in the length of intestinal bypass.RESEARCH DESIGN AND METHODSA total of 53 patients with type 2 diabetes (T2D) and obesity were randomized to either standard limb RYGB (50-cm biliopancreatic limb) or long limb RYGB (150-cm biliopancreatic limb). They underwent measurements of GLP-1 and insulin secretion following a mixed meal and insulin sensitivity using euglycemic hyperinsulinemic clamps at baseline and 2 weeks and at 20% weight loss after surgery.RESULTSBoth groups exhibited enhancement in postprandial GLP-1 secretion and improvements in glycemia compared with baseline. There were no significant differences in postprandial peak concentrations of GLP-1, time to peak, insulin secretion, and insulin sensitivity.CONCLUSIONSThe findings of this study demonstrate that lengthening of the intestinal bypass in RYGB does not affect GLP-1 secretion. Thus, the characteristic enhancement of GLP-1 response after RYGB might not depend on delivery of nutrients to more distal intestinal segments.