Acute Intravenous Administration Research Articles

Suppression of the Excitability of Nociceptive Secondary Sensory Neurons Following Systemic Administration of Astaxanthin in Rats

Although astaxanthin (AST) has demonstrated a modulatory effect on voltage-gated Ca2+ (Cav) channels and excitatory glutamate neuronal transmission in vitro, particularly on the excitability of nociceptive sensory neurons, its action in vivo remains to be determined. This research sought to determine if an acute intravenous administration of AST in rats reduces the excitability of wide-dynamic range (WDR) spinal trigeminal nucleus caudalis (SpVc) neurons in response to nociceptive and non-nociceptive mechanical stimulation in vivo. In anesthetized rats, extracellular single-unit recordings were carried out on SpVc neurons following mechanical stimulation of the orofacial area. The average firing rate of SpVc WDR neurons in response to both gentle and painful mechanical stimuli significantly and dose-dependently decreased after the application of AST (1–5 mM, i.v.), and maximum suppression of discharge frequency for both non-noxious and nociceptive mechanical stimuli occurred within 10 min. These suppressive effects persisted for about 20 min. These results suggest that acute intravenous AST administration suppresses the SpVc nociceptive transmission, possibly by inhibiting Cav channels and excitatory glutamate neuronal transmission, implicating AST as a potential therapeutic agent for the treatment of trigeminal nociceptive pain without side effects.

Effect of acute intravenous beta-blocker administration on myocardial blood flow during same-day hybrid CCTA/PET imaging

This study aimed to evaluate the impact of acute intravenous beta-blocker administration on myocardial blood flow (MBF) during same-day hybrid coronary computed tomography angiography (CCTA) and 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI). Previous research on the discontinuation of oral beta-blockers before MPI has shown mixed results, with no studies yet exploring the acute intravenous administration in the context of same-day hybrid imaging. This retrospective study included patients with suspected chronic coronary syndromes undergoing same-day hybrid CCTA/13N-ammonia PET MPI. Exclusion criteria comprised coronary artery stenosis ≥ 50% or regional perfusion abnormalities on PET, and baseline oral beta-blocker medication. Intravenous metoprolol (up to 30 mg) was administered as needed for heart rate control before CCTA. MBF measurements were obtained at rest (rMBF) and during stress (sMBF), and myocardial flow reserve (MFR) was calculated. After excluding 281 patients, 154 were eligible for propensity-score matching, resulting in 108 patients divided into two equal groups based on beta-blocker administration. The groups showed no significant differences in baseline characteristics. Among those who received beta-blockers, there was a significant decrease in sMBF (2.21 [IQR 1.72–2.78] versus 2.46 [2.08–2.99] ml∙min−1∙g−1, p = 0.027) and MFR (3.46 [2.70–4.05] versus 3.79 [3.22–4.46], p = 0.030), respectively, compared to those who did not receive beta-blockers. In contrast, rMBF remained unaffected (0.65 [0.54–0.78] versus 0.64 [0.55–0.76] ml∙min−1∙g−1, p = 0.931). Acute intravenous beta-blocker administration significantly impacts MBF, leading to a slight reduction in sMBF and MFR. In contrast, rMBF appears unaffected, suggesting that beta-blockers primarily affect the coronary capacity to respond to vasodilators.

Acute Dapagliflozin Administration Ameliorates Cardiac Surgery-Associated Acute Kidney Injury in a Rabbit Model.

Several studies have shown that sodium-glucose cotransporter-2 inhibitors have a renoprotective effect on acute kidney injury (AKI), but their effect on cardiac surgery-associated AKI is unknown. AKI was induced in 25 rabbits without diabetes mellitus by cardiopulmonary bypass (CPB) for 2 h and they were divided into 5 groups: sham; dapagliflozin-treated sham; CPB; dapagliflozin-treated CPB; and furosemide-treated CPB (n=5 in each group). Dapagliflozin was administered via the femoral vein before initiating CPB. Kidney tissue and urine and blood samples were collected after the surgical procedure. There were no differences in the hemodynamic variables of each group. Dapagliflozin reduced serum creatinine and blood urea nitrogen concentrations, and increased overall urine output (all P<0.05). Hematoxylin and eosin staining showed that the tubular injury score was improved after dapagliflozin administration (P<0.01). Dapagliflozin administration mitigated reactive oxygen species and kidney injury molecule-1 as assessed by immunohistochemistry (both P<0.0001). Protein expression analysis showed improvement of inflammatory cytokines and apoptosis, and antioxidant enzyme expression was elevated (all P<0.05) through activation of the nuclear factor erythroid 2-related factor 2 pathway (P<0.01) by dapagliflozin. Acute intravenous administration of dapagliflozin protects against CPB-induced AKI. Dapagliflozin may have direct renoprotective effects in renal tubular cells.

Tissue Distribution, Pharmacokinetics, and Effect of Hematological and Biochemical Parameters of Acute Intravenous Administration of Silver Nanoparticles in Rats.

The widespread biomedical and commercial applications of silver nanoparticles (AgNPs) have increased their potential for human and environmental exposure and toxicity to human health. The bio-distribution and toxicity of AgNPs in rodents following inhalation, intratracheal instillation, and oral ingestion are well documented; however, little is known about the bio-distribution of intravenously (IV)-administered AgNPs and their organ-specific pathophysiological effects. Here, we investigate the pharmacokinetic pattern and tissue distribution of AgNPs in male rats following IV administration. The animals were humanely sacrificed after 10 min, 1 h, 6 h, 12 h, 24 h, and 168 h of AgNP administration, and the silver (Ag) content was measured from blood samples and various tissues following acid digestion. The AgNPs were readily absorbed and subsequently distributed into most organs predominantly in the colon, small intestine, kidney, and heart after 6 h; however, they were the highest in the spinal cord after 168 h. White blood cells (WBCs) were significantly increased (42-60%) in AgNP-administered animals at all time points except 10 min. Regarding platelets, all AgNP-administered animals showed counts 7.8-39.2% lower, with the lowest count at 168 h post-administration. In the case of lymphocytes (LYMs), the AgNP-treated animals exhibited a count 19.5-41% lower at 10 min and 1 h post-administration; however, the animals at 168 h post-administration showed a count 30.5% more. The mean corpuscular hemoglobin (MCH) counts from the AgNP-treated animals were decreased by 50-62%. The concentrations of aspartate transaminase (AST), urea, and creatinine were increased in the AgNP-treated animals. Taken together, the results suggest that the acute IV administration of AgNPs alters metabolic and hematological parameters in animals and may pose a health risk to humans.

FRI007 Kisspeptin Does Not Affect Food Intake In Women With Overweight Or Obesity

Abstract Disclosure: C. Izzi-Engbeaya: None. M. Choudhury: None. B. Patel: None. B. Muzi: None. A. Qayum: None. E.G. Mills: None. M. Ahsan: None. M. Phylactou: None. S. Clarke: None. L. Aslett: None. A.N. Comninos: None. A. Abbara: None. T. Tan: None. W.S. Dhillo: None. Background: Kisspeptin neurons in the hypothalamus are believed to play a role in mediating the interaction between metabolic and reproductive health. Functional neuroanatomical connections exist between kisspeptin neurons and appetite-regulating neurons in the arcuate nucleus of the hypothalamus. Female (but not male) global kisspeptin receptor knockout mice have reduced food intake compared to controls. However, studies of kisspeptin administration have yielded conflicting results, with either decreased, or unchanged food intake reported in rodent studies. Consistent with some of the literature, kisspeptin administration does not influence food intake in men. However, the effects of kisspeptin on food intake have not previously been studied in women. Research Question: What is the effect of kisspeptin administration on food intake in women? Methodology: A randomized controlled crossover study was performed in women with overweight or obesity (BMI &amp;gt;25 kg/m2) who were not in receipt of exogenous oral and/or transdermal estrogens or progestins. Each woman attended two study visits in random order following an overnight fast. During each study visit they received either a 2-hour intravenous infusion of kisspeptin-54 at a rate of 1.0 nmol/kg/hr, or a rate-matched vehicle infusion. The study was single-blinded, with participants unaware of the infusion identity. Participants were given an ad libitum meal 45 minutes after the start of each infusion. Blood samples were taken for reproductive and metabolic profiling, and visual analogue scales (VAS) to assess hunger were completed at regular intervals throughout both study visits. Data are presented as mean±SD. Results: 17 women (age 49±12 years, BMI 34±7 kg/m2) completed both study visits. As expected, LH levels were higher during kisspeptin than during vehicle infusion (p&amp;lt;0.01), confirming bioactivity of the kisspeptin dose. Pre-meal estradiol levels were similar during kisspeptin and vehicle infusions (p=0.34). There were no differences in pre-meal hunger VAS scores 30 mins after the start of the infusion (kisspeptin 5.2±2.7 vs vehicle 5.9±2.3, p=0.33) or bodyweight-adjusted food intake (kisspeptin 6.8±3.7 kcal/kg vs vehicle 6.2±2.8 kcal/kg, p=0.33). There were also no differences in glucose (p=0.97) or insulin (p=0.68) levels between kisspeptin and vehicle infusions. Conclusions: Acute intravenous administration of a biologically active dose of kisspeptin did not affect food intake or hunger in women with overweight or obesity. Furthermore, kisspeptin administration did not alter fasting or post-prandial glucose levels. This is the first study to examine the effects of kisspeptin on hunger and food intake in women and provides reassuring safety data for the ongoing development of kisspeptin-based therapeutics. Presentation: Friday, June 16, 2023

Effects of acute intravenous lipopolysaccharide administration on the plasma lipidome and metabolome in lactating Holstein cows experiencing hyperlipidemia.

The effects of lipopolysaccharides (i.e., endotoxin; LPS) on metabolism are poorly defined in lactating dairy cattle experiencing hyperlipidemia. Our objective was to explore the effects of acute intravenous LPS administration on metabolism in late-lactation Holstein cows experiencing hyperlipidemia induced by intravenous triglyceride infusion and feed restriction. Ten non-pregnant lactating Holstein cows (273 ± 35 d in milk) were administered a single bolus of saline (3 mL of saline; n [Formula: see text] 5) or LPS (0.375 [Formula: see text]g of LPS/kg of body weight; n [Formula: see text] 5). Simultaneously, cows were intravenously infused a triglyceride emulsion and feed restricted for 16 h to induce hyperlipidemia in an attempt to model the periparturient period. Blood was sampled at routine intervals. Changes in circulating total fatty acid concentrations and inflammatory parameters were measured. Plasma samples were analyzed using untargeted lipidomics and metabolomics. Endotoxin increased circulating serum amyloid A, LPS-binding protein, and cortisol concentrations. Endotoxin administration decreased plasma lysophosphatidylcholine (LPC) concentrations and increased select plasma ceramide concentrations. These outcomes suggest modulation of the immune response and insulin action. Lipopolysaccharide decreased the ratio of phosphatidylcholine to phosphatidylethanomanine, which potentially indicate a decrease in the hepatic activation of phosphatidylethanolamine N-methyltransferase and triglyceride export. Endotoxin administration also increased plasma concentrations of pyruvic and lactic acids, and decreased plasma citric acid concentrations, which implicate the upregulation of glycolysis and downregulation of the citric acid cycle (i.e., the Warburg effect), potentially in leukocytes. Acute intravenous LPS administration decreased circulating LPC concentrations, modified ceramide and glycerophospholipid concentrations, and influenced intermediary metabolism in dairy cows experiencing hyperlipidemia.

Intravenous administration of LPS activates the kynurenine pathway in healthy male human subjects: a prospective placebo-controlled cross-over trial

BackgroundAdministration of lipopolysaccharide (LPS) from Gram-negative bacteria, also known as the human endotoxemia model, is a standardized and safe model of human inflammation. Experimental studies have revealed that peripheral administration of LPS leads to induction of the kynurenine pathway followed by depressive-like behavior and cognitive dysfunction in animals. The aim of the present study is to investigate how acute intravenous LPS administration affects the kynurenine pathway in healthy male human subjects.MethodsThe present study is a prospective, single-blinded, randomized, placebo-controlled cross-over study to investigate the effects of intravenously administered LPS (Escherichia coli O113, 2 ng/kg) on tryptophan and kynurenine metabolites over 48 h and their association with interleukin-6 (IL-6) and C-reactive protein (CRP). The study included 10 healthy, non-smoking men (18–40 years) free from medication. Statistical differences in tryptophan and kynurenine metabolites as well as associations with IL-6 and CRP in LPS and placebo treated subjects were assessed with linear mixed-effects models.ResultsSystemic injection of LPS was associated with significantly lower concentrations of plasma tryptophan and kynurenine after 4 h, as well as higher concentrations of quinolinic acid (QUIN) after 48 h compared to the placebo injection. No differences were found in kynurenic acid (KYNA) or picolinic acid plasma concentrations between LPS or placebo treatment. The KYNA/kynurenine ratio peaked at 6 h post LPS injection while QUIN/kynurenine maintained significantly higher from 3 h post LPS injection until 24 h. The kynurenine/tryptophan ratio was higher at 24 h and 48 h post LPS treatment. Finally, we report an association between the kynurenine/tryptophan ratio and CRP.ConclusionsOur findings strongly support the concept that an inflammatory challenge with LPS induces the kynurenine pathway in humans, activating both the neurotoxic (QUIN) and neuroprotective (KYNA) branch of the kynurenine pathway.Trial registrationThis study is based on a study registered at ClinicalTrials.gov, NCT03392701. Registered 21 December 2017.

Poly(ethylene glycol)-Alendronate-Coated Magnetite Nanoparticles Do Not Alter Cardiovascular Functions and Red Blood Cells' Properties in Hypertensive Rats.

In this study, magnetite nanoparticles were prepared and coated with poly(ethylene glycol) terminated by alendronate to ensure firm binding to the iron oxide surface. Magnetic nanoparticles, designated as magnetite coated with poly(ethylene glycol)-alendronate (Fe3O4@PEG-Ale), were characterized in terms of number-average (Dn) and hydrodynamic (Dh) size, ζ-potential, saturation magnetization, and composition. The effect of particles on blood pressure, vascular functions, nitric oxide (NO), and superoxide production in the tissues of spontaneously hypertensive rats, as well as the effect on red blood cell (RBC) parameters, was investigated after intravenous administration (1 mg Fe3O4/kg of body weight). Results showed that Fe3O4@PEG-Ale particles did negatively affect blood pressure, heart rate and RBC deformability, osmotic resistance and NO production. In addition, Fe3O4@PEG-Ale did not alter functions of the femoral arteries. Fe3O4@PEG-Ale induced increase in superoxide production in the kidney and spleen, but not in the left heart ventricle, aorta and liver. NO production was reduced only in the kidney. In conclusion, the results suggest that acute intravenous administration of Fe3O4@PEG-Ale did not produce negative effects on blood pressure regulation, vascular function, and RBCs in hypertensive rats.

The Crushing Effects Of Opiate Abuse: Two Cases Illustrating The Morphologic Features Of Acute And Chronic Intravenous Administration Of Crushed Oral Opiates

Abstract Introduction/Objective Drug overdose related deaths in the US have shown a four-fold increase over the past two decades, increasing from 6.1 to 21.7 per 100,000, the increasing majority of which involve synthetic opioid use. With this continuing increase, it is important for pathologists to become aware of unusual gross and microscopic changes related to unconventional modes of drug abuse. A less recognized unconventional method for opiate abusers to ingest these substances exemplified by our two cases is by crushing oral tablets and inhaling or injecting the drug intravenously, subcutaneously or intramuscularly. Methods The two cases being presented show morphological features of acute and chronic opiate abuse by autopsy study. Case 1 was a 38-year old female, who underwent spinal fusion surgery 1 month prior, and was found unresponsive at home. Case 2 was a 37-year-old female with a history of Antiphospholipid Antibody Syndrome (APA) and upper limb DVTs who was found unresponsive one day after elective utero-vaginal prolapse surgery. Results At autopsy, Case 1 showed extensive embolization of polarizable foreign body material (possible “pill filler”) and fibrin in small and medium sized vessels without inflammatory reaction in the lungs bilaterally. The foreign material was also present in the small vessels of the heart associated with multifocal acute inflammation, hemorrhage, foreign body giant cell reaction and multiple myocardial infarcts (elevated troponin levels clinically). Blood and vitreous fluid were positive for oxycodone. At autopsy, Case 2 showed an extensive angiocentric miliary pattern of granulomatous reaction to polarizable foreign material, consistent with pill filler in the lungs bilaterally. This foreign material was also present within the lumens and walls of pulmonary vessels and in the skin of the legs. Chronic changes of hypertrophic cardiomyopathy, hepatic cirrhosis and congestive splenomegaly were evident. The blood oxycodone levels were ten times the normal limit. Conclusion These cases illustrate the importance of recognizing the clinical and morphological features of unorthodox acute and chronic opiate abuse. Lack of familiarity with their differing features can lead to a delay in diagnosis and institution of appropriate timely management and treatment.

Gintonin influences the morphology and motility of adult brain neurons via LPA receptors

BackgroundGintonin is an exogenous ginseng-derived G-protein-coupled lysophosphatidic acid (LPA) receptor ligand. LPA induces in vitro morphological changes and migration through neuronal LPA1 receptor. Recently, we reported that systemic administration of gintonin increases blood-brain barrier (BBB) permeability via the paracellular pathway and its binding to brain neurons. However, little is known about the influences of gintonin on in vivo neuron morphology and migration in the brain. Materials and methodsWe examined the effects of gintonin on in vitro migration and morphology using primary hippocampal neural precursor cells (hNPC) and in vivo effects of gintonin on adult brain neurons using real time microscopic analysis and immunohistochemical analysis to observe the morphological and locational changes induced by gintonin treatment. ResultsWe found that treating hNPCs with gintonin induced morphological changes with a cell rounding following cell aggregation and return to individual neurons with time relapses. However, the in vitro effects of gintonin on hNPCs were blocked by the LPA1/3 receptor antagonist, Ki16425, and Rho kinase inhibitor, Y27632. We also examined the in vivo effects of gintonin on the morphological changes and migration of neurons in adult mouse brains using anti-NeuN and -neurofilament H antibodies. We found that acute intravenous administration of gintonin induced morphological and migrational changes in brain neurons. Gintonin induced some migrations of neurons with shortened neurofilament H in the cortex. The in vivo effects of gintonin were also blocked by Ki16425. ConclusionThe present report raises the possibility that gintonin could enter the brain and exert its influences on the migration and morphology of adult mouse brain neurons and possibly explains the therapeutic effects of neurological diseases behind the gintonin administration.

Trastuzumab increases pulmonary vein arrhythmogenesis through modulating pulmonary vein electrical and conduction properties via phosphatidylinositol 3-kinase signaling.

Objective(s):Drug-induced atrial fibrillation (AF) is considered an adverse effect of chemotherapeutic drugs. AF is a crucial risk factor for stroke, heart failure, myocardial infarction, and mortality. Pulmonary veins (PVs) are considered triggers inducing AF, and the sinoatrial node (SAN) may modulate PV activity and participate in AF genesis. AF was associated with early discontinuation of trastuzumab in patients with breast cancer. However, whether trastuzumab directly modulates the electrophysiological characteristics of PV and SAN remains unclear. Materials and Methods:ECG and conventional microelectrode system were used to record rabbit heart rhythm in vivo and electrical activities in vitro from isolated SAN, PV, and SAN-PV preparations. Results:Trastuzumab reduced the beating rate in isolated PV and SAN preparations at 1, 10, and 30 μM (particularly in isolated SAN preparations) and induced burst firings in isolated PV preparations at 10 μΜ. In addition, trastuzumab (10 μM) induced SAN-PV conduction block and burst firings, which were blocked by wortmannin (a PI3K inhibitor, 100 nM). Similarly, ECG recordings showed that acute intravenous administration of trastuzumab (10 mg/kg) reduced rabbit heart rates. Conclusion:Trastuzumab increased PV arrhythmogenesis through interfering with PI3K signaling, which may contribute to the genesis of AF.

Dynamic changes in circulating levels of metabolites in the portal-drained viscera of finishing pigs receiving acute administration of l-arginine.

In this study, we examined the effects of acute intravenous administration of l-arginine on circulating levels of metabolites in the portal-drained viscera (PDV) of 12 barrows surgically fitted with chronic catheters in the portal vein. At day 14 post-surgery, the pigs were fasted for 12hr and then randomly allocated to one of three groups to receive administration of normal saline, l-alanine [103mg/kg body weight (BW), isonitrogenous control] or l-arginine-HCl (61mg/kg BW), via the portal vein. Blood samples were obtained from the carotid artery before and at 30-min intervals for 5hr after the administration of saline or amino acid in order to determine metabolic profiles. The results showed that, compared with the saline treatment, arginine infusion increased plasma concentrations of insulin-like growth factor-I, arginine and cystine in the portal vein plasma, whereas plasma concentrations of threonine, serine, leucine and methionine were reduced. These findings indicate that increasing arginine concentrations in the portal vein alters the metabolic profile in swine, an established animal model for studying human nutrition and metabolism.

P6342Subcutaneous delivery of NPA7, first-in-class novel bispecific designer peptide: enhances cardiorenal function and suppresses renin and aldosterone in vivo and in vitro

Abstract Introduction The rapid increase of patients of heart failure (HF) is a major health burden worldwide. Most importantly is the need to develop innovative new drugs for treatment of HF, such as sacubitril/valsartan which in part functions by enhancing the natriuretic peptides (NPs). We engineered NPA7 as a novel 30 amino acid bispecific designer peptide which activates the particulate guanylyl cyclase A receptor (pGC-A)/cGMP and for which the NPs both ANP and BNP are ligands and the Mas-receptor (MasR)/cAMP pathways for Angiotensin 1–7 (Ang1–7) is the endogenous ligand. We previously reported that acute intravenous (IV) administration of NPA7 shows cardiorenal protective and renin-aldosterone suppressing actions that go beyond the native peptides, BNP or Ang 1–7, which may have therapeutic potential for HF. Purpose To support the clinical development of NPA7 as a potential therapy in HF which promotes NP and MasR pathways, we investigated the actions and stability of subcutaneous (SQ) administration of NPA7 in normal canines. We also defined NPA7's peptide stability and metabolites in canine plasma. Methods Plasma and urinary cGMP, cardiorenal and renin-aldosterone responses to SQ injection (10μg/kg) were determined over 4 hours in normal canines (n=5) in vivo. Ex vivo, we established stability of NPA7 and key metabolites in canine serum using liquid chromatography-mass spectrometry (LC-MS). Data are expressed as mean ± SEM. * P&lt;0.05 vs. BL. Results In vivo, SQ NPA7 resulted in a sustained increase at 2 hours in plasma (BL: 10±3; 120 min: 30±6* pmol/ml) and urinary (BL: 1033±198; 120 min: 5792±857* pmol/min) cGMP, GFR (BL: 29±6; 120 min: 70±12* ml/min) and sodium excretion (BL: 18±10; 120 min: 144±33* ueq/min). We observed a gradual reduction in BP at 60 min (BL: 109±4; 60 min: 99±7* mmHg) with a sustained decrease in PCWP at 4 hours (BL: 5±0.9; 240 min: 3.1±0.6* mmHg). SQ NPA7 also suppressed plasma renin and aldosterone up to 3 hours after SQ injection. LC-MS revealed that NPA7 was highly stable with both the pGC-A and MasR activating moieties intact ex vivo in canine serum with a disappearance time of 2 hours. We also identified 2 major NPA7 metabolites NPA71–27 and NPA71–28. Conclusions SQ NPA7 possesses cGMP activating, cardiac unloading, diuretic, natriuretic, and renin-aldosterone suppressing actions in normal canines. NPA7 is also highly stable in serum. These studies support SQ administration as an effective delivery strategy for NPA7, a first-in-class innovative bispecific dual pGC-A/MasR activator now in preclinical development for HF.

Successful Brain Delivery of Andrographolide Loaded in Human Albumin Nanoparticles to TgCRND8 Mice, an Alzheimer's Disease Mouse Model.

Andrographolide (AG) was encapsulated in human albumin nanoparticles (AG NPs), and their crossing properties of the blood-brain barrier (BBB), brain distribution, and effects in TgCRND8 mice were evaluated. The development of appropriate NP formulations is mandatory because of the scarce BBB permeability properties of AG. Developed NPs had proper size (mean size: 159.2 ± 4.5 nm), size distribution (PDI nearby 0.12 ± 0.01), and ζ potential (-24.8 ± 1.2 mV), which were not affected by sodium fluorescein (NAF) loading. When AG was loaded to NPs, it slightly affected their size (210.4 ± 3.2 nm) and ζ potential (-20.3 ± 1.5) but not the PDI. Both NAF and AG had a remarkable encapsulation efficiency (more than 99%). The in vitro release of AG from the NPs reached the highest percentage (48%) after 24 h, and the Higuchi’s equation was found to be the best fitting model (R2 = 0.9635). Both AG and AG NPs did not alter the viability of N2a murine neuroblastoma cells when compared with the untreated control cells. In the step-down inhibitory avoidance test, AG NPs administered to TgCRND8 mice significantly improved their performance (P < 0.0001), reaching levels comparable to those displayed by wild-type mice. In the object recognition test, treated and untreated animals showed no deficiencies in exploratory activity, directional movement toward objects, and locomotor activity. No cognitive impairments (discrimination score) were detected in TgCRND8 mice (P < 0.0001) treated with AG NPs. After acute intravenous administration (200 µl), NPs loaded with the probe NAF were detected in the brain parenchyma of TgCRND8 mice. Immunofluorescent analyses evidenced the presence of NPs both in the pE3-Aβ plaque surroundings and inside the pE3-Aβ plaque, indicative of the ability of these NPs to cross the BBB and to penetrate in both undamaged and damaged brain tissues. Furthermore, the immunohistochemical analysis of GFAP-positive astrocytes in the hippocampus of Tg mice evidenced the anti-inflammatory activity of AG when AG NPs were intraperitoneally administered. AG was not effective in counteracting amyloid Aβ aggregation and the resulting toxicity but significantly decreased the oxidative stress levels. In conclusion, AG NPs have extraordinary versatility, nontoxicity, nonimmunogenicity, strong biocompatibility, high biodegradability, and astonishing loading capacity of drug.

Descriptive Psychopathology of the Acute Effects of Intravenous Delta-9-Tetrahydrocannabinol Administration in Humans.

Background: Cannabis use can increase the risk of psychosis, and the acute administration of its key psychoactive ingredient, delta-9-tetrahydrocannabinol (∆9-THC), can induce transient psychotomimetic symptoms. Methods: A double-blind, randomized, placebo-controlled crossover design was used to investigate the symptomatic effects of acute intravenous administration of ∆9-THC (1.19 mg/2 mL) in 16 healthy participants (seven males) with modest previous cannabis exposure. Results: In the 20 min following acute ∆9-THC administration, symptomatic effects of at least mild severity were present in 94% of the cohort, with moderate to severe symptoms having a much lower prevalence (19%). Nearly one-third (31%) of the volunteers were still experiencing protracted mild symptomatic effects 2.5 h after exposure to ∆9-THC. Compared to the Δ9-THC challenge, most of the study participants did not experience any symptomatic effects following placebo administration (62%). Acute physical reactions were 2.5 times more frequent after Δ9-THC (31%) than placebo (12%). Male and female participants differed in terms of acute Δ9-THC effects, with some negative symptoms occurring more frequently in female (56% to 89%) than male participants (0% to 29%), and acute physical reactions occurring exclusively in the female gender (56%). Conclusions: These results have implications for future research, also in light of cannabis being the most widely used illicit drug.

The Newly Synthesized Pyrazole Derivative 5-(1-(3 Fluorophenyl)-1H-Pyrazol-4-yl)-2H-Tetrazole Reduces Blood Pressure of Spontaneously Hypertensive Rats via NO/cGMO Pathway

The search for new antihypertensive drugs has grown in recent years because of high rate of morbidity among hypertensive patients and several side effects that are associated with the first-line medications. The current study sought to investigate the antihypertensive effect of a newly synthesized pyrazole derivative known as 5-(1-(3 fluorophenyl)-1H-pyrazol-4-yl)-2H-tetrazole (LQFM-21). Spontaneously hypertensive rats (SHR) were used to evaluate the effect of LQFM-21 on mean arterial pressure (MAP), heart rate (HR), renal vascular conductance (RVC), arterial vascular conductance (AVC), baroreflex sensitivity (BRS) index, and vascular reactivity. Acute intravenous (iv) administration of LQFM-21 (0.05, 0.1, 0.2, and 0.4 mg kg-1) reduced MAP and HR, and increased RVC and AVC. Chronic oral administration of LQFM-21 (15 mg kg-1) for 15 days reduced MAP without altering BRS. The blockade of muscarinic receptors and nitric oxide synthase by intravenous infusion of atropine and L-NAME, respectively, attenuated cardiovascular effects of LQFM-21. In addition, ex vivo experiments showed that LQFM-21 induced an endothelium-dependent relaxation in isolated aortic rings from SHR. This effect was blocked by guanylyl cyclase inhibitor (ODQ) and L-NAME. These findings suggest the involvement of muscarinic receptor and NO/cGMP pathway in the antihypertensive and vasodilator effects of LQFM-21.

Metformin inhibits gluconeogenesis via a redox-dependent mechanism in vivo.

Metformin, the universal first-line treatment for type 2 diabetes, exerts its therapeutic glucose-lowering effects by inhibiting hepatic gluconeogenesis. However, the primary molecular mechanism of this biguanide remains unresolved, though it has been suggested to act, at least partially, by mitochondrial complex I inhibition. Here, we show that clinically-relevant plasma metformin concentrations achieved by acute intravenous, acute intraportal or chronic oral administration in awake normal and diabetic rats inhibit gluconeogenesis from lactate and glycerol but not from pyruvate and alanine, implicating an increased cytosolic redox state in mediating metformin’s antihyperglycemic effect. All of these effects occurred independent of complex I inhibition, evidenced by unaltered hepatic energy charge and citrate synthase flux. Normalizing the cytosolic redox state by infusion of methylene blue or substrates that contribute to gluconeogenesis independently of the cytosolic redox state abrogated metformin-mediated inhibition of gluconeogenesis in vivo. Additionally, in mice expressing constitutively active acetyl-CoA carboxylase, metformin acutely decreased hepatic glucose production and increased the hepatic cytosolic redox state without altering hepatic triglyceride content or gluconeogenic enzyme expression. These studies demonstrate that metformin, at clinically-relevant plasma concentrations, inhibits hepatic gluconeogenesis in a redox-dependent manner independent of reductions in citrate synthase flux, hepatic nucleotide concentrations, acetyl-CoA carboxylase activity, or gluconeogenic enzyme protein expression.

Abstract 4915: Preclinical pharmacology and toxicology of intravenous BPM31510, a coenzyme Q10-containing lipid nanodispersion

Abstract Coenzyme Q10 (CoQ10) plays an important role in cellular metabolism with redox capabilities beyond the mitochondria. Although, the role of CoQ10 in providing benefit in diseases such as cardiovascular, neurodegeneration, and cancer is well established, it has been limited by the absence of delivery methods to achieve physiologically relevant bio-availability. BPM31510 is a CoQ10 (ubidecarenone) containing lipid nanodispersion that delivers supraphysiological concentrations of CoQ10 to tissues, cells and mitochondria. BPM31510 is currently in clinical trials for the treatment of solid tumors including pancreatic cancer and glioblastoma multiforme. This study describes the preclinical pharmacokinetic (PK) and toxicokinetic assessment of BPM31510 (62.5, 125, and 250 mg/kg) after acute (single) intravenous (IV) administration and chronic (3 times a week for 4 weeks), and after a two week recovery from the last exposure in rats. Here, it was demonstrated that the formulation enables an effective delivery of CoQ10 with a robust increase in plasma level and dose-dependent accumulation in several tissues. PK analysis of mean plasma concentration of CoQ10 after a single and repeat dose administration revealed a dose proportion effect on peak (Cmax) and total exposure (AUC0-t). Tissue analysis of CoQ10 levels demonstrates a dose-dependent increase in liver, lung and pancreas 72 hours post-last dose. A dose dependent elimination was observed in both male and females. No difference in pharmacokinetic of CoQ10 using this formulation was observed between males and females. Notably, chronic exposure to BPM31510 does not lead to toxicities as assessed by hematology and coagulation, clinical chemistry, histopathology and gross necropsy. These results indicate that the effective delivery and bioavailability of supraphysiological levels of CoQ10 after IV administration of BPM31510 is well tolerated. Citation Format: David Linsenmayer, Shiva Kazerounian, Khampaseuth Thapa, Carrie Spencer, Aishwarya Sarma, John McCook, Stephane Gesta, Vivek Vishnudas, Niven R. Narain, Rangaprasad Sarangarajan. Preclinical pharmacology and toxicology of intravenous BPM31510, a coenzyme Q10-containing lipid nanodispersion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4915.

Systemic administration of α-lipoic acid suppresses excitability of nociceptive wide-dynamic range neurons in rat spinal trigeminal nucleus caudalis

Although a modulatory role has been reported for α-lipoic acid (LA) on T-type Ca2+ channels in the nervous system, the acute effects of LA in vivo, particularly on nociceptive transmission in the trigeminal system, remain to be determined. The aim of the present study was to investigate whether acute intravenous LA administration to rats attenuates the excitability of wide dynamic range (WDR) spinal trigeminal nucleus caudalis (SpVc) neurons in response to nociceptive and non-nociceptive mechanical stimulation in vivo. Extracellular single unit recordings were made from seventeen SpVc neurons in response to orofacial mechanical stimulation of pentobarbital-anesthetized rats. Responses to both non-noxious and noxious mechanical stimuli were analyzed in the present study. The mean firing frequency of SpVc WDR neurons in response to both non-noxious and noxious mechanical stimuli was significantly and dose-dependently inhibited by LA (1–100 mM, i.v.) and maximum inhibition of the discharge frequency of both non-noxious and noxious mechanical stimuli was seen within 5 min. These inhibitory effects lasted for approximately 10 min. These results suggest that acute intravenous LA administration suppresses trigeminal sensory transmission, including nociception, via possibly blocking T-type Ca2+ channels. LA may be used as a therapeutic agent for the treatment of trigeminal nociceptive pain.

Intravenous Cellular Therapies for Acute Ischemic Stroke.

The promise of cellular therapies as a treatment for stroke and other injuries and diseases of the central nervous system (CNS) has compelled researchers, clinicians, patients, and the public for the last 2 decades. Various types of cells isolated from numerous tissue sources have demonstrated benefit in improving outcomes in animal stroke models when administered intravenously in an acute time frame (minutes to days) after stroke onset. Data supporting the homing of cells to the brain and proximal to the infarct after intravenous administration is lacking, begging the question “How are cells from an array of tissue sources functioning to improve neurological recovery without the presence of the cells at the primary site of injury?” The last 10 years have seen an increased focus on understanding the importance the peripheral immune system plays in exacerbating and complicating treatment and recovery of patients with stroke. Based on seminal observations from the Willing, Pennypacker, and Offner laboratories, we now know that the spleen participates in the immune response in the acute time frame after stroke onset in animal studies, and the involvement of spleen has now been confirmed in observational human stroke studies.1–3 The accumulation of laboratory and clinical data supports the contention that acute intravenous administration of cell therapies provides long-term benefit after stroke by modulating the initial peripheral immune response, potentiating tissue repair and recovery, and these data may collectively signal the emergence of a new class of therapies for the treatment of ischemic stroke. After the initial injury in the brain after ischemic stroke, a complex set of inflammatory cascades are initiated resulting in the engagement of both innate and adaptive immune systems. Glial cells—the endogenous phagocytic immune cells of the brain—become activated and in concert with the injured parenchymal tissue, signal the peripheral immune system …