Implementation of a bundled protocol significantly reduces risk of spinal cord ischemia after branched or fenestrated endovascular aortic repair.

OBJECTIVE: Spinal cord ischemia (SCI) is a devastating complication after branched or fenestrated endovascular aortic repair (B/FEVAR) for thoracoabdominal aortic disease. The purpose of this analysis was to describe the impact of a bundled clinical care protocol designed to reduce the risk of SCI in this population of patients. METHODS: A bundled SCI prevention protocol including cerebrospinal fluid drainage, blood pressure parameters, transfusion goals, and pharmacologic adjuncts (steroids, naloxone) was initiated in May 2015. Before that date, portions of the protocol (cerebrospinal fluid drainage in particular) were used in an informal fashion in patients perceived to be at high risk. B/FEVAR cases completed from January 2012 to May 2016 were reviewed, and outcomes before (n = 223) and after (n = 70) SCI bundle application were compared. The primary end point was the incidence of SCI events. Secondary end points included length of stay, complications, and survival. High-risk patients for SCI were defined as those undergoing B/FEVAR resulting in aortic coverage equivalent to open Crawford extent I to III thoracoabdominal aortic aneurysm (TAAA) repair. Survival was estimated using Kaplan-Meier life-table analysis. RESULTS: Postprotocol patients were more likely to be older (75 ± 7 vs 72 ± 8 years; P = .03), to have an American Society of Anesthesiologists class 4 designation (94% vs 81%; P = .04), and to be treated for TAAA (67% vs 56%; P = .004). Postprotocol pre-emptive spinal drain use was greater in high-risk patients (100% vs 87%; P = .04) but significantly decreased in lower risk patients (suprarenal aneurysm or extent IV TAAA: 5% after protocol implementation vs 21% before protocol implementation; P = .04). Rates of any SCI before and after implementation of the bundled protocol were 13% (n = 29 of 223) and 3% (n = 2 of 70; P = .007), respectively. In comparing high-risk patients, protocol use resulted in an even more significant reduction in SCI rate (19% [28 of 144] vs 4% [2 of 50]; P = .004). Postoperative morbidity (41% vs 33%; P = .2) and 30-day mortality (5% vs 1%; P = .3) were not different between groups. However, patients treated on protocol had significantly improved 1-year survival (99% ± 1% after protocol implementation vs 90% ± 2% before protocol implementation; log-rank, P = .05). CONCLUSIONS: Implementation of a bundled multimodal protocol may significantly reduce risk of SCI after B/FEVAR, with the greatest risk reduction occurring in the most vulnerable patients. Interestingly, reduction in SCI risk was associated with improvement in 1-year survival.

Discovery and characterization of a G protein-biased agonist that inhibits ß-arrestin recruitment to the D2 dopamine receptor.

A high-throughput screening campaign was conducted to interrogate a 380,000+ small-molecule library for novel D2 dopamine receptor modulators using a calcium mobilization assay. Active agonist compounds from the primary screen were examined for orthogonal D2 dopamine receptor signaling activities including cAMP modulation and ß-arrestin recruitment. Although the majority of the subsequently confirmed hits activated all signaling pathways tested, several compounds showed a diminished ability to stimulate ß-arrestin recruitment. One such compound (MLS1547; 5-chloro-7-[(4-pyridin-2-ylpiperazin-1-yl)methyl]quinolin-8-ol) is a highly efficacious agonist at D2 receptor-mediated G protein-linked signaling, but does not recruit ß-arrestin as demonstrated using two different assays. This compound does, however, antagonize dopamine-stimulated ß-arrestin recruitment to the D2 receptor. In an effort to investigate the chemical scaffold of MLS1547 further, we characterized a set of 24 analogs of MLS1547 with respect to their ability to inhibit cAMP accumulation or stimulate ß-arrestin recruitment. A number of the analogs were similar to MLS1547 in that they displayed agonist activity for inhibiting cAMP accumulation, but did not stimulate ß-arrestin recruitment (i.e., they were highly biased). In contrast, other analogs displayed various degrees of G protein signaling bias. These results provided the basis to use pharmacophore modeling and molecular docking analyses to build a preliminary structure-activity relationship of the functionally selective properties of this series of compounds. In summary, we have identified and characterized a novel G protein-biased agonist of the D2 dopamine receptor and identified structural features that may contribute to its biased signaling properties.

A cerebrospinal fluid microRNA signature as biomarker for glioblastoma.

PURPOSE: To develop a cerebrospinal fluid (CSF) miRNA diagnostic biomarker for glioblastoma. EXPERIMENTAL DESIGN: Glioblastoma tissue and matched CSF from the same patient (obtained prior to tumor manipulation) were profiled by TaqMan OpenArray® Human MicroRNA Panel. CSF miRNA profiles from glioblastoma patients and controls were created from three discovery cohorts and confirmed in two validation cohorts. RESULTS: miRNA profiles from clinical CSF correlated with those found in glioblastoma tissues. Comparison of CSF miRNA profiles between glioblastoma patients and non-brain tumor patients yielded a tumor "signature" consisting of nine miRNAs. The "signature" correlated with glioblastoma tumor volume (p=0.008). When prospectively applied to cisternal CSF, the sensitivity and specificity of the 'signature' for glioblastoma detection were 67% and 80%, respectively. For lumbar CSF, the sensitivity and specificity of the signature were 28% and 95%, respectively. Comparable results were obtained from analyses of CSF extracellular vesicles (EVs) and crude CSF. CONCLUSION: We report a CSF miRNA signature as a "liquid biopsy" diagnostic platform for glioblastoma.

Investigation of the binding and functional properties of extended length D3 dopamine receptor-selective antagonists.

The D3 dopamine receptor represents an important target in drug addiction in that reducing receptor activity may attenuate the self-administration of drugs and/or disrupt drug or cue-induced relapse. Medicinal chemistry efforts have led to the development of D3 preferring antagonists and partial agonists that are >100-fold selective vs. the closely related D2 receptor, as best exemplified by extended-length 4-phenylpiperazine derivatives. Based on the D3 receptor crystal structure, these molecules are known to dock to two sites on the receptor where the 4-phenylpiperazine moiety binds to the orthosteric site and an extended aryl amide moiety docks to a secondary binding pocket. The bivalent nature of the receptor binding of these compounds is believed to contribute to their D3 selectivity. In this study, we examined if such compounds might also be "bitopic" such that their aryl amide moieties act as allosteric modulators to further enhance the affinities of the full-length molecules for the receptor. First, we deconstructed several extended-length D3-selective ligands into fragments, termed "synthons", representing either orthosteric or secondary aryl amide pharmacophores and investigated their effects on D3 receptor binding and function. The orthosteric synthons were found to inhibit radioligand binding and to antagonize dopamine activation of the D3 receptor, albeit with lower affinities than the full-length compounds. Notably, the aryl amide-based synthons had no effect on the affinities or potencies of the orthosteric synthons, nor did they have any effect on receptor activation by dopamine. Additionally, pharmacological investigation of the full-length D3-selective antagonists revealed that these compounds interacted with the D3 receptor in a purely competitive manner. Our data further support that the 4-phenylpiperazine D3-selective antagonists are bivalent and that their enhanced affinity for the D3 receptor is due to binding at both the orthosteric site as well as a secondary binding pocket. Importantly, however, their interactions at the secondary site do not allosterically modulate their binding to the orthosteric site.

Discovery, optimization, and characterization of novel D2 dopamine receptor selective antagonists.

The D2 dopamine receptor (D2 DAR) is one of the most validated drug targets for neuropsychiatric and endocrine disorders. However, clinically approved drugs targeting D2 DAR display poor selectivity between the D2 and other receptors, especially the D3 DAR. This lack of selectivity may lead to undesirable side effects. Here we describe the chemical and pharmacological characterization of a novel D2 DAR antagonist series with excellent D2 versus D1, D3, D4, and D5 receptor selectivity. The final probe 65 was obtained through a quantitative high-throughput screening campaign, followed by medicinal chemistry optimization, to yield a selective molecule with good in vitro physical properties, metabolic stability, and in vivo pharmacokinetics. The optimized molecule may be a useful in vivo probe for studying D2 DAR signal modulation and could also serve as a lead compound for the development of D2 DAR-selective druglike molecules for the treatment of multiple neuropsychiatric and endocrine disorders.