Justin L. Poklis

Blockade of Endocannabinoid-Degrading Enzymes Attenuates Neuropathic Pain

Direct-acting cannabinoid receptor agonists are well known to reduce hyperalgesic responses and allodynia after nerve injury, although their psychoactive side effects have damped enthusiasm for their therapeutic development. Alternatively, inhibiting fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), the principal enzymes responsible for the degradation of the respective endogenous cannabinoids, anandamide (AEA) and 2-arachydonylglycerol (2-AG), reduce nociception in a variety of nociceptive assays, with no or minimal behavioral effects. In the present study we tested whether inhibition of these enzymes attenuates mechanical allodynia, and acetone-induced cold allodynia in mice subjected to chronic constriction injury of the sciatic nerve. Acute administration of the irreversible FAAH inhibitor, cyclohexylcarbamic acid 3′-carbamoylbiphenyl-3-yl ester (URB597), or the reversible FAAH inhibitor, 1-oxo-1-[5-(2-pyridyl)-2-yl]-7-phenylheptane (OL-135), decreased allodynia in both tests. This attenuation was completely blocked by pretreatment with either CB1 or CB2 receptor antagonists, but not by the TRPV1 receptor antagonist, capsazepine, or the opioid receptor antagonist, naltrexone. The novel MAGL inhibitor, 4-nitrophenyl 4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate (JZL184) also attenuated mechanical and cold allodynia via a CB1, but not a CB2, receptor mechanism of action. Whereas URB597 did not elicit antiallodynic effects in FAAH(-/-) mice, the effects of JZL184 were FAAH-independent. Finally, URB597 increased brain and spinal cord AEA levels, whereas JZL184 increased 2-AG levels in these tissues, but no differences in either endo-cannabinoid were found between nerve-injured and control mice. These data indicate that inhibition of FAAH and MAGL reduces neuropathic pain through distinct receptor mechanisms of action and present viable targets for the development of analgesic therapeutics.

A case of 25I-NBOMe (25-I) intoxication: a new potent 5-HT2A agonist designer drug

Context. Abuse of synthetic stimulant compounds resulting in significant toxicity is being increasingly reported by poison centers. Toxicologic assessment is complicated by inconsistent manufacturing processes and limited laboratory testing. We describe a case of self-reported exposure to 25-I (25I-NBOMe), a novel phenethylamine derivative, with subsequent quantification in serum. Case details. An 18-year-old male presented to the emergency department (ED) with severe agitation and hallucinations after jumping out of a moving car. He was tachycardiac (150–160 bpm) and hypertensive (150–170 mm Hg systolic and 110 mg Hg diastolic), and required physical restraints and treatment with intravenous lorazepam administration. His symptoms gradually improved and vital signs returned to normal over 48 h, though he continued to have episodes of aggressiveness. An assay was developed by our analytical toxicology laboratory for 25-I, and serum obtained during ED evaluation and treatment was found to contain 0.76 ng/ml of 25-I. Case discussion. For 25I-NBOMe, 25-I is a common abbreviation for 25I-NBOMe, which is a (n-benzyl) phenethylamine in the 2C “family.”Initially synthesized for research, cases of self-reported use of 25-I have recently appeared in the literature, some of which contain qualitative urine confirmation. There are no commercially available quantitative assays, and no previous reports have published serum concentrations. 25-I is a potent new synthetic drug with apparent significant behavioral toxicity that can be detected and quantified in serum.

Postmortem detection of 25I-NBOMe [2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine] in fluids and tissues determined by high performance liquid chromatography with tandem mass spectrometry from a traumatic death

We present a traumatic fatality of a 19-year-old man who had ingested blotter paper containing 25I-NBOMe [2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine]. Postmortem specimens were analyzed by high performance liquid chromatography with tandem mass spectrometry (HPLC/MS/MS). Toxicology findings for fluids based upon blood or urine calibrators were as follows: peripheral blood, 405 pg/mL; heart blood, 410 pg/mL; urine, 2.86 ng/mL; and vitreous humor, 99 pg/mL. While findings based upon the method of standard additions were: gastric contents, 7.1 μg total; bile, 10.9 ng/g; brain, 2.54 ng/g and liver, 7.2 ng/g. To our knowledge the presented case is the first postmortem case of 25I-NBOMe intoxication documented by toxicological analysis of tissues and body fluids.

Lysosomal Targeting and Trafficking of Acid Sphingomyelinase to Lipid Raft Platforms in Coronary Endothelial Cells

Objective—The purpose of this study was to determine whether lysosome trafficking and targeting of acid sphingomyelinase (ASMase) to this organelle contribute to the formation of lipid raft (LR) signaling platforms in the membrane of coronary arterial endothelial cells (CAECs). Methods and Results—By measurement of fluorescent resonance energy transfer (FRET), it was found that in FasL-stimulated CAECs, membrane lamp1 (a lysosome marker protein) or Fas and GM1 (a LR marker) were trafficking together. Cofocal colocalization assay showed that ceramide was enriched in these LR platforms. Further studies demonstrated that these ceramide molecules in LR platforms were colocalized with ASMase, a ceramide producing enzyme. Fluorescence imaging of living CAECs loaded with lysosomal specific dyes demonstrated that lysosomes fused with membrane on FasL stimulation. In the presence of lysosome function inhibitors, bafilomycin (Baf) or glycyl-l-phenylalanine-&bgr;-naphthylamide (GPN), these FasL-induced changes were abolished. Moreover, this FasL-induced formation of LR platforms was also blocked in ECs transfected with siRNA of sortilin, an intracellular transporter for targeting of ASMase to lysosomes. Functionally, FasL-induced impairment of vasodilator response was reversed by lysosomal inhibitors or sortilin gene silencing. Conclusions—Lysosomal trafficking and targeting of ASMase are importantly involved in LRs clustering in ECs membrane, leading to the formation of signaling platforms or signalosomes.

Role of Sphingolipid Mediator Ceramide in Obesity and Renal Injury in Mice Fed a High Fat Diet

The present study tested a hypothesis that excess accumulation of sphingolipid, ceramide, its metabolites, or a combination contributes to the development of obesity and associated kidney damage. Liquid chromatography/mass spectrometry analysis demonstrated that C57BL/6J mice on the high-fat diet (HFD) had significantly increased plasma total ceramide levels compared with animals fed a low-fat diet (LFD). Treatment of mice with the acid sphingomyelinase (ASMase) inhibitor amitriptyline significantly attenuated the HFD-induced plasma ceramide levels. Corresponding to increase in plasma ceramide, the HFD significantly increased the body weight gain, plasma leptin concentration, urinary total protein and albumin excretion, glomerular damage index, and adipose tissue ASMase activity compared with the LFD-fed mice. These HFD-induced changes were also significantly attenuated by treatment of mice with amitriptyline. In addition, the decline of plasma glucose concentration after an intraperitoneal injection of insulin (0.15 U/kg b.wt.) was more sustained in mice on the HFD with amitriptyline than on the HFD alone. Intraperitoneal injection of glucose (3 g/kg b.wt.) resulted in a slow increase followed by a rapid decrease in the plasma glucose concentration in LFD and HFD plus amitriptyline-treated mice, but such blood glucose response was not observed in HFD-fed mice. Immunofluorescence analysis demonstrated a decrease in the podocin and an increase in the desmin in the glomeruli of HFD-fed mice compared with the LFD and HFD plus amitriptyline-treated mice. In conclusion, our results reveal a pivotal role for ceramide biosynthesis in obesity, metabolic syndrome, and associated kidney damage.

Toxicities Associated With NBOMe Ingestion—A Novel Class of Potent Hallucinogens: A Review of the Literature

BACKGROUND A new class of synthetic hallucinogens called NBOMe has emerged as drugs of abuse. OBJECTIVE Our aim was to conduct a systematic review of published reports of toxicities associated with NBOMe ingestion. METHODS We searched PubMed for relevant English-language citations that described adverse effects from analytically confirmed human NBOMe ingestion. Demographic and clinical data were extracted. RESULTS A total of 10 citations met the criteria for inclusion, representing 20 individual patients. 25I-NBOMe was the most common analogue identified, followed by 25B-NBOMe and 25C-NBOMe. Fatalities were reported in 3 (15%) cases. Of all the patients, 7 (35%) were discharged after a period of observation, whereas 8 (40.0%) required admission to an intensive care unit. The most common adverse effects were agitation (85.0%), tachycardia (85.0%), and hypertension (65.0%). Seizures were reported in 8 (40.0%) patients. The most common abnormalities reported on laboratory tests were elevated level of creatinine kinase (45.0%), leukocytosis (25.0%), and hyperglycemia (20.0%). CONCLUSION NBOMe ingestion is associated with severe adverse effects. Clinicians need to have a high index of suspicion for NBOMe ingestion in patients reporting the recent use of hallucinogens.

Postmortem tissue distribution of acetyl fentanyl, fentanyl and their respective nor-metabolites analyzed by ultrahigh performance liquid chromatography with tandem mass spectrometry

In the last two years, an epidemic of fatal narcotic overdose cases has occurred in the Tampa area of Florida. Fourteen of these deaths involved fentanyl and/or the new designer drug, acetyl fentanyl. Victim demographics, case histories, toxicology findings and causes and manners of death, as well as, disposition of fentanyl derivatives and their nor-metabolites in postmortem heart blood, peripheral blood, bile, brain, liver, urine and vitreous humor are presented. In the cases involving only acetyl fentanyl (without fentanyl, n=4), the average peripheral blood acetyl fentanyl concentration was 0.467 mg/L (range 0.31 to 0.60 mg/L) and average acetyl norfentanyl concentration was 0.053 mg/L (range 0.002 to 0.086 mg/L). In the cases involving fentanyl (without acetyl fentanyl, n=7), the average peripheral blood fentanyl concentration was 0.012 mg/L (range 0.004 to 0.027 mg/L) and average norfentanyl blood concentration was 0.001 mg/L (range 0.0002 to 0.003 mg/L). In the cases involving both acetyl fentanyl and fentanyl (n=3), the average peripheral blood acetyl fentanyl concentration was 0.008 mg/L (range 0.006 to 0.012 mg/L), the average peripheral blood acetyl norfentanyl concentration was 0.001 mg/L (range 0.001 to 0.002 mg/L), the average peripheral blood fentanyl concentration was 0.018 mg/L (range 0.015 to 0.021mg/L) and the average peripheral blood norfentanyl concentration was 0.002 mg/L (range 0.001 mg/L to 0.003 mg/L). Based on the toxicology results, it is evident that when fentanyl and/or acetyl fentanyl were present, they contributed to the cause of death. A novel ultrahigh performance liquid chromatography (UPLC) tandem mass spectrometry (MS/MS) method to identify and quantify acetyl fentanyl, acetyl norfentanyl, fentanyl and norfentanyl in postmortem fluids and tissues is also presented.

Analysis of 25I-NBOMe, 25B-NBOMe, 25C-NBOMe and Other Dimethoxyphenyl-N-[(2-Methoxyphenyl) Methyl]Ethanamine Derivatives on Blotter Paper

In recent years, N-methoxybenzyl-methoxyphenylethylamine (NBOMe) derivatives, a class of designer hallucinogenic drugs, have become popular drugs of abuse. These drugs have been the cause of severe intoxications and even deaths. They act as 5-HT2A receptors agonists and have been reported to produce serotonin-like syndrome with bizarre behavior, severe agitation and seizures persisting for as long as 3 days. The most commonly reported derivatives are 25I-NBOMe, 25B-NBOMe and 25C-NBOMe, respectively 2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl) methyl]ethanamine, N-(2-methoxybenzyl)-2,5-dimethoxy-4-bromophenethylamine and N-(2-methoxybenzyl)-2,5-dimethoxy-4-chlorophenethylamine. Like many low dose hallucinogenic drugs these compounds are often sold on blotter paper. Three different types of commercially available blotter papers reported to contain NBOMe derivatives were obtained. These blotter papers were screened using Direct Analysis in Real Time AccuTOF(TM) mass spectrometry followed by confirmation and quantification by high-performance liquid chromatography triple quadrapole mass spectrometry. The major drug present on each of the three blotter products was different, 25I-NBOMe, 25C-NBOMe or 25B-NBOMe. The blotter papers were also found to have minute amounts of two or three NBOMe derivative impurities of 25H-NBOMe, 25I-NBOMe, 25C-NBOMe, 25B-NBOMe and/or 25D-NBOMe.

Visfatin-induced lipid raft redox signaling platforms and dysfunction in glomerular endothelial cells.

Adipokines have been reported to contribute to glomerular injury during obesity or diabetes mellitus. However, the mechanisms mediating the actions of various adipokines on the kidney remained elusive. The present study was performed to determine whether acid sphingomyelinase (ASM)-ceramide associated lipid raft (LR) clustering is involved in local oxidative stress in glomerular endothelial cells (GECs) induced by adipokines such as visfatin and adiponectin. Using confocal microscopy, visfatin but not adiponectin was found to increase LRs clustering in the membrane of GECs in a dose and time dependent manner. Upon visfatin stimulation ASMase activity was increased, and an aggregation of ASMase product, ceramide and NADPH oxidase subunits, gp91(phox) and p47(phox) was observed in the LR clusters, forming a LR redox signaling platform. The formation of this signaling platform was blocked by prior treatment with LR disruptor filipin, ASMase inhibitor amitriptyline, ASMase siRNA, gp91(phox) siRNA and adiponectin. Corresponding to LR clustering and aggregation of NADPH subunits, superoxide (O(2)(-)) production was significantly increased (2.7 folds) upon visfatin stimulation, as measured by electron spin resonance (ESR) spectrometry. Functionally, visfatin significantly increased the permeability of GEC layer in culture and disrupted microtubular networks, which were blocked by inhibition of LR redox signaling platform formation. In conclusion, the injurious effect of visfatin, but not adiponectin on the glomerular endothelium is associated with the formation of LR redox signaling platforms via LR clustering, which produces local oxidative stress resulting in the disruption of microtubular networks in GECs and increases the glomerular permeability.

Formation of lipid raft redox signalling platforms in glomerular endothelial cells: an early event of homocysteine-induced glomerular injury.

The present study tested the hypothesis that homocysteine (Hcys)‐induced ceramide production stimulates lipid rafts (LRs) clustering on the membrane of glomerular endothelial cells (GECs) to form redox signalling platforms by aggregation and activation of NADPH oxidase subunits and thereby enhances superoxide (O2.−) production, leading to glomerular endothelial dysfunction and ultimate injury or sclerosis. Using confocal microscopy, we first demonstrated a co‐localization of LR clusters with NADPH oxidase subunits, gp91phox and p47phox in the GECs membrane upon Hcys stimulation. Immunoblot analysis of floated detergent‐resistant membrane fractions found that in LR fractions NADPH oxidase subunits gp91phox and p47phox are enriched and that the activity of this enzyme dramatically increased. We also examined the effect of elevated Hcys on the cell monolayer permeability in GECs. It was found that Hcys significantly increased GEC permeability, which was blocked by inhibition of LR redox signalling platform formation. Finally, we found that Hcys‐induced enhancement of GEC permeability is associated with the regulation of microtubule stability through these LR‐redox platforms. It is concluded that the early injurious effect of Hcys on the glomerular endothelium is associated with the formation of redox signalling platforms via LR clustering, which may lead to increases in glomerular permeability by disruption of microtubule network in GECs.