HMR1402, a potassium ATP channel blocker during hyperdynamic porcine endotoxemia: effects on hepato-splanchnic oxygen exchange and metabolism

Objective To assess the effects of the potassium ATP (KATP) channel blocker HMR1402 (HMR) on systemic and hepato-splanchnic hemodynamics, oxygen exchange and metabolism during hyperdynamic porcine endotoxemia.Design Prospective, randomized, controlled study with repeated measures.Setting Animal laboratory.Subjects Eighteen pigs allocated to receive endotoxin alone (control group, CON, n=10) or endotoxin and HMR (6 mg/kg h^–1, n=8).Interventions Anesthetized, mechanically ventilated, and instrumented pigs receiving continuous i.v. endotoxin were resuscitated with hetastarch to maintain mean arterial pressure (MAP) >60 mmHg. Twelve hours after starting the endotoxin infusion, they received HMR or its vehicle for another 12 h.Results HMR transiently increased MAP by about 15 mmHg, but this effect was only present during the first 1 h of infusion. The HMR decreased cardiac output due to a fall in heart rate, and thereby reduced liver blood flow. While liver O₂ delivery and uptake remained unchanged, HMR induced hyperlactatemia [from 1.5 (1.1; 2.0), 1.4 (1.2; 1.8), and 1.2 (0.8; 2.0) to 3.1 (1.4; 3.2), 3.2 (1.6; 6.5), and 3.0 (1.0; 5.5) mmol/l in the arterial, portal and hepatic venous samples, respectively] and further increased arterial [from 8 (3; 13) to 23 (11; 57); p<0.05], portal [from 9 (4; 14) to 23 (14; 39); p<0.05] and hepatic vein [from 7 (0; 15) to 30 (8; 174), p<0.05] lactate/pyruvate ratios indicating impaired cytosolic redox state.Conclusion The short-term beneficial hemodynamic effects of KATP channel blockers have to be weighted with the detrimental effect on mitochondrial respiration.P. Asfar and Z. Iványi equally contributed to this work     

Prevention of latently expressed CYP2C11, CYP3A2, and growth hormone defects in neonatally monosodium glutamate-treated male rats by the N-methyl-D-aspartate receptor antagonist dizocilpine maleate

Neonatal administration of monosodium glutamate (MSG) can produce latently expressed defects in drug metabolism and growth hormone secretion as well as stunted growth and obesity. Instead of secreting growth hormone in the masculine episodic profile, plasma hormone levels are generally undetectable in affected adult male rats. Moreover, male-specific isoforms of cytochrome P450 (P450; e.g., CYP2C11 and CYP3A2), whose combined levels comprise the bulk of the total hepatic P450 in adult male rats, are similarly undetectable in these animals. Since "signaling elements" in the masculine episodic growth hormone profile are solely responsible for the elevated characteristic male-like expression levels of CYP2C11 and CYP3A2, suppression of the isoforms in the MSG-treated rats appeared to be caused by the simple absence of the hormone from the circulation. However, the reported failures of restored physiologic masculine growth hormone profiles to correct the P450 defects suggested the occurrence of direct MSG-induced liver damage independent of the well known hypothalamic lesions produced by the amino acid. Concurrent administration of dizocilpine maleate (MK-801), a selective and highly potent noncompetitive N-methyl-D-aspartate receptor antagonist of glutamate, completely prevented the adverse effects of neonatal MSG treatment on P450 expression, growth hormone secretion, and growth parameters, indicating that the amino acid-induced defects are solely a result of neuronal (i.e., hypothalamic) damage produced at the time of MSG exposure. The irreversibility of the P450 damage is described as resulting from secondary defects initially induced by the neuronal lesions.     

Cure of prediabetic mice by viral infections involves lymphocyte recruitment along an IP-10 gradient

Viruses can cause but can also prevent autoimmune disease. This dualism has certainly hampered attempts to establish a causal relationship between viral infections and type 1 diabetes (T1D). To develop a better mechanistic understanding of how viruses can influence the development of autoimmune disease, we exposed prediabetic mice to various viral infections. We used the well-established NOD and transgenic RIP-LCMV models of autoimmune diabetes. In both cases, infection with the lymphocytic choriomeningitis virus (LCMV) completely abrogated the diabetic process. Interestingly, such therapeutic viral infections resulted in a rapid recruitment of T lymphocytes from the islet infiltrate to the pancreatic draining lymph node, where increased apoptosis was occurring. In both models this was associated with a selective and extensive expression of the chemokine IP-10 (CXCL10), which predominantly attracts activated T lymphocytes, in the pancreatic draining lymph node, and in RIP-LCMV mice it depended on the viral antigenic load. In RIP-LCMV mice, blockade of TNF-alpha or IFN-gamma in vivo abolished the prevention of T1D. Thus, virally induced proinflammatory cytokines and chemokines can influence the ongoing autoaggressive process beneficially at the preclinical stage, if produced at the correct location, time, and levels.     

Necrotizing enterocolitis as a prognostic factor for the neurodevelopmental outcome of preterm infants - match control study after 2 years

Purpose

Necrotizing enterocolitis (NEC) in very low birth weight infants is a risk factor for developmental delay. To our knowledge, there are no studies published investigating the neurodevelopmental outcome of patients with NEC comparing surgically treated and conservatively treated patients versus match paired controls. The aim of this retrospective case control study was to measure the neurodevelopmental outcome of patients with NEC who were treated surgically or conservatively

Managing Traps and Pitfalls During Initial Steps of an ECMO Retrieval Program Using a Miniaturized Portable System: What Have We Learned From the First Two Years?

The aim of this study was to provide early and mid‐term results of the newly established extracorporeal membrane oxygenation (ECMO) retrieval service in a tertiary cardiothoracic center using the miniaturized portable Cardiohelp System (Maquet, Rastatt, Germany). A particular attention was paid to organizational and logistic specifics as well as challenges and pitfalls associated with initial phase of the program. From January 2015 until January 2017 a heterogenic group of 28 consecutive patients underwent ECMO implantation in distant hospitals for acute cardiac, pulmonary or combined failure as a bridge‐to‐decision and were subsequently transported to our institution. Each cannulation was performed bedside on intensive care units (ICU) using the Seldinger's technique. Early outcomes and mid‐term overall survival with up to two‐year follow‐up along with the impact of ongoing cardiopulmonary resuscitation (CPR) on outcome were presented. Also, changes in hemodynamics and tissue perfusion factors 24 h after ECMO implantation were evaluated. ECMO implantations were performed in 15 distant departments with the median distance of 23(10;40) (maximum 60) km. A total of 15 patients (54%) were cannulated under CPR with the median duration of 30(20;110) (maximum 180) min. After 24 h of support there were significant improvements in SvO₂ (P = 0.021), mean arterial pressure (P = 0.027), FiO₂ (P = 0.001), lactate (P = 0.001), and pH (P < 0.001). The mean ECMO support duration was 96 ± 100 (maximum 384) hours, whereas 11 patients (40%) were weaned off support and discharged from hospital. Overall cumulative survival in patients without the need for CPR was 61.5% at one week and 38.5% at 1 month, 6 month, and 1 year, whereas patients requiring CPR survived in 40% at one week, and 33.3% at 1 month, 6 month, and 1 year (Log‐Rank (Mantel‐Cox) P = 0.374, Breslow (Generalized Wilcoxon) P = 0.162). Our initial experience shows that launching new ECMO retrieval programs in centers with sufficient ICU capacities and local ECMO experience can be feasible and associated with acceptable “real world” results despite the initial learning curve. Rapid logistical organization and team flexibility are the key points to ensure comparable survival of patients requiring prolonged CPR.     

A rapid in vitro screening for delivery of peptide-derived peptidase inhibitors as potential drug candidates via epithelial peptide transporters

Targeting drugs or prodrugs to a specific enzyme by simultaneously targeting cell membrane carriers for efficient transport should provide the highest bioavailability along with specificity at the site of action. The peptide transporters PEPT1 and PEPT2 are expressed in a variety of tissues, including the brush-border membranes of epithelial cells of the small intestine and kidney. The transporters accept a wide range of substrates and are therefore good targets for a transporter-mediated drug delivery. Here, we report a screening procedure for peptidomimetic drug candidates combining two independent expression systems: 1) a competition assay in transgenic Pichia pastoris yeast cells expressing either mammalian PEPT1 or PEPT2 for identifying substrate interaction with the transporter binding site; and 2) a Xenopus laevis-based oocyte expression of the peptide transporter for assessing electrogenic transport of drug candidates. Based on the known oral availability and in vivo efficacy of the dipeptidyl peptidase IV (DPIV) inhibitor isoleucine-thiazolidide and its peptide-like structure, we first tested whether this compound is a substrate of epithelial peptide transporters. Additionally, a series of structurally related inhibitors were analyzed for transport. We identified various compounds that serve as substrates of the intestinal peptide transporter PEPT1. In contrast, none of these DPIV inhibitors showed electrogenic transport by PEPT2, although a variety of the compounds displayed good affinities for competition in peptide uptake in PEPT2-expressing cells, suggesting that they may serve as efficient inhibitors. In conclusion, we have applied an in vitro screening system that predicts efficient intestinal absorption of peptide-derived peptidase inhibitors via PEPT1 in vivo.     

RNA-sequencing highlights differential regulated pathways involved in cell cycle and inflammation in orbitofacial neurofibromas

Although most commonly benign, neurofibromas (NFs) can have devastating functional and cosmetic effects in addition to the possibility of malignant transformation. Orbitofacial NFs, in particular, may cause progressive, disfiguring tumors of the lid, brow, temple, face, and orbit, and clinical evidence suggests that they may have increased local aggressiveness compared to NFs developing at other sites. The purpose of this study was to identify biological differences between orbitofacial NFs and those occurring at other anatomic sites. We performed RNA-sequencing in orbitofacial (n = 10) and non-orbitofacial (n = 9) NFs. Differential gene expression analysis demonstrated that a variety of gene sets including genes involved in cell proliferation, interferon, and immune-related pathways were enriched in orbitofacial NF. Comparisons with publicly available databases of various Schwann cell tumors and malignant peripheral nerve sheath tumor (MPNST) revealed a significant overlap of differentially expressed genes between orbitofacial versus non-orbitofacial NF and plexiform NF versus MPNST. In summary, we identified gene expression differences between orbitofacial NF and NFs occurring at other locations. Further investigation may be warranted, given that orbitofacial NF are notoriously difficult to treat and associated with disproportionate morbidity.