Cerebral Oedema, Blood-Brain Barrier Breakdown and the Decrease in Na(+),K(+)-ATPase Activity in the Cerebral Cortex and Hippocampus are Prevented by Dexamethasone in an Animal Model of Maple Syrup Urine Disease

In Vivo Intracerebral Administration of α-Ketoisocaproic Acid to Neonate Rats Disrupts Brain Redox Homeostasis and Promotes Neuronal Death, Glial Reactivity, and Myelination Injury

Maple syrup urine disease (MSUD) is caused by severe deficiency of branched-chain α-keto acid dehydrogenase complex activity, resulting in tissue accumulation of branched-chain α-keto acids and amino acids, particularly α-ketoisocaproic acid (KIC) and leucine. Affected patients regularly manifest with acute episodes of encephalopathy including seizures, coma, and potentially fatal brain edema during the newborn period. The present work investigated the ex vivo effects of a single intracerebroventricular injection of KIC to neonate rats on redox homeostasis and neurochemical markers of neuronal viability (neuronal nuclear protein (NeuN)), astrogliosis (glial fibrillary acidic protein (GFAP)), and myelination (myelin basic protein (MBP) and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase)) in the cerebral cortex and striatum. KIC significantly disturbed redox homeostasis in these brain structures 6 h after injection, as observed by increased 2',7'-dichlorofluorescein oxidation (reactive oxygen species generation), malondialdehyde levels (lipid oxidative damage), and carbonyl formation (protein oxidative damage), besides impairing the antioxidant defenses (diminished levels of reduced glutathione and altered glutathione peroxidase, glutathione reductase, and superoxide dismutase activities) in both cerebral structures. Noteworthy, the antioxidants N-acetylcysteine and melatonin attenuated or normalized most of the KIC-induced effects on redox homeostasis. Furthermore, a reduction of NeuN, MBP, and CNPase, and an increase of GFAP levels were observed at postnatal day 15, suggesting neuronal loss, myelination injury, and astrocyte reactivity, respectively. Our data indicate that disruption of redox homeostasis, associated with neural damage caused by acute intracerebral accumulation of KIC in the neonatal period may contribute to the neuropathology characteristic of MSUD patients.

The anti-inflammatory and analgesic activities of 2Br-Crebanine and Stephanine from Stephania yunnanenses H. S.Lo

Ethnopharmacological relevance: Crebanine (Cre) and Stephanine (Step) are isoquinoline aporphine-type alkaloids that are extracted from Stephania yunnanenses H. S. Lo. Plants of the Stephania genus are often used for treatment of stomach pain, abdominal pain, and rheumatoid arthritis. Both Cre and Step exhibit strong activities but are also associated with a certain level of toxicity, 10,11-dibrominecrebanine (2Br-Cre) is a bromine-modified derivative of Cre that we prepared and tested in order to reduce toxicity and enhance efficacy. Aim of this study: To investigate the anti-inflammatory and analgesic effects of 2Br-Cre and Step based on previous research findings and explore the specific biological mechanisms involved. Materials and methods: The anti-inflammatory and analgesic effects of 2Br-Cre and Step were investigated using a range of experimental models, including xylene-induced ear edema, carrageenan-induced pleurisy, carrageenan-induced paw edema, the hot-plate test, the naloxone antagonism test and the acetic acid writhing test. A model of chronic constriction injury (CCI) of the sciatic nerve was also established to investigate therapeutic effects. A RAW264.7 cell model was established using lipopolysaccharide (LPS) to estimate the effects of these compounds on cytokines levels. Results: 2Br-Cre and step significantly inhibited ear edema, paw edema and presented anti-inflammatory activity in the pleurisy model by inhibiting leukocyte migration and nitric oxide (NO) production, and by reducing the levels of PGE2. 2Br-Cre and Step significantly increased the pain threshold of mice subjected to heat stimulation; the effect was blocked by naloxone, thus suggesting that the analgesic effects of 2Br-Cre and Step were mediated by opioid receptors. 2Br-Cre and Step inhibited the frequency of writhing and prolonged the latency of writhing, and reduced the abnormal increase in the levels of BDNF in the serum and brain, thus alleviating the pain caused by CCI. In addition, 2Br-Cre and Step significantly inhibited the production of several inflammatory cytokines (IL-6, IL-1β and TNF-α) by LPS-induced RAW264.7 macrophages (p < .01). Conclusion: 2Br-Cre and Step exerted remarkable anti-inflammatory and analgesic effects. As a structural modification of Cre, 2Br-Cre retains the anti-inflammatory and analgesic activity of Cre but with better efficacy. Consequently, 2Br-Cre should be investigated further as a lead compound for analgesia.

First In-Human Medical Imaging with a PASylated 89Zr-Labeled Anti-HER2 Fab-Fragment in a Patient with Metastatic Breast Cancer

Purpose

PASylation® offers the ability to systematically tune and optimize the pharmacokinetics of protein tracers for molecular imaging. Here we report the first clinical translation of a PASylated Fab fragment (⁸⁹Zr∙Df-HER2-Fab-PAS₂₀₀) for the molecular imaging of tumor-related HER2 expression.

Methods

A patient with HER2-positive metastatic breast cancer received 37 MBq of ⁸⁹Zr∙Df-HER2-Fab-PAS₂₀₀ at a total mass dose of 70 μg. PET/CT was carried out 6, 24, and 45 h after injection, followed by image analysis of biodistribution, normal organ uptake, and lesion targeting.

Results

Images show a biodistribution typical for protein tracers, characterized by a prominent blood pool 6 h p.i., which decreased over time. Lesions were detectable as early as 24 h p.i. ⁸⁹Zr∙Df-HER2-Fab-PAS₂₀₀ was tolerated well.

Conclusion

This study demonstrates that a PASylated Fab tracer shows appropriate blood clearance to allow sensitive visualization of small tumor lesions in a clinical setting.

Administration of branched-chain amino acids increases the susceptibility to lipopolysaccharide-induced inflammation in young Wistar rats

Maple Syrup Urine Disease (MSUD) is an inborn error of the metabolism caused by defects in the branched a-ketoacid dehydrogenase complex (BCKDC), leading to the accumulation of branched chain amino acids (BCAAs) (leucine, isoleucine and valine). Patients with MSUD present a series of neurological dysfunction. Recent studies have been associated the brain damage in the MSUD with inflammation and immune system activation. MSUD patients die within a few months of life due to recurrent metabolic crises and neurologic deterioration, often precipitated by infection or other stresses. In this regard, our previous results showed that the inflammatory process, induced by lipopolysaccharide (LPS), associated with high levels of BCAAs causes blood-brain barrier (BBB) breakdown due to hyperactivation of MMPs. Thus, we hypothesize that the synergistic action between high concentrations of BCAAs (H-BCAAs) and LPS on BBB permeability and hyperactivation of MMPs could be through an increase in the production of cytokines and RAGE protein levels. We observed that high levels of BCAA in infant rats are related to increased brain inflammation induced by LPS administration. In addition, BCAA exposure led to an increase on brain RAGE expression of young rats. The brain inflammation was characterized by enhanced levels of interleukin 1 β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and Interferon- γ (IFN-γ), and decreased content of interleukin-10 (IL-10). Therefore, MSUD is associated with a more intense neuroinflammation induced by LPS infection.

Dexamethasone changes the pharmacokinetics of amitriptyline and reduces its accumulation in rat brain: The roles of P-gp and cyp3a2

The wide spread use of central nervous system (CNS) drugs has caused thousands of deaths in clinical practice while there are few antidotes or effective treatments to decrease their accumulation in CNS. In this study, we used amitriptyline (AMI) and dexamethasone (DEX) as the corresponding poisoning and pre-protecting drugs, respectively, to study whether DEX has the potential to reduce AMI accumulation in brain. By measuring the pharmacokinetic data of AMI and its main metabolite nortriptyline (NOR), we found that DEX possibly accelerated the metabolism and elimination of AMI with minimal effects on the concentrations of NOR in blood. Nevertheless, the results indicated that DEX reduced the brain/plasma concentration ratio of AMI and NOR, even if the plasma concentration of NOR had an upward trend. Western blot results showed the overexpression of cyp3a2 and P-gp in rat liver and brain capillaries tissues. We propose that cyp3a2 and P-gp could be upregulated in the liver and blood-brain barrier (BBB) when using DEX. Further experiments suggest that DEX may serve as the ligand of PXR to induce P-gp expression.

Prophylactic effect and mechanism of p-coumaric acid against hypoxic cerebral edema in mice

Our previous study found that the anti-hypoxia effect of Tibetan turnip (Brassica rapa ssp. rapa) is directly related to its p-Coumaric acid (CA) and glucoside (pCoumaric acid-beta-d-glucopyranoside, CAG) contents. The present study aimed to investigate the role and mechanism of CA against hypoxic cerebral edema. Male mice were randomly divided into one normoxia group and three hypoxia groups, which were gavaged with sterilized water, CA, or dexamethasone, respectively, once daily for 4 days. The mice were then exposed to normoxia or hypoxia (9.5% O₂) for 24 h. The results showed that the brain water content (BWC) and blood-brain-barrier permeability were significantly lower in the CA treatment group than in the hypoxia vehicle group. Mice in the CA treatment group showed good blood-brain-barrier integrity; increased Na⁺-K⁺-ATPase activity and mitochondrial membrane potential; decreased oxidative stress and inflammation; and increased occludin protein levels. Prophylactic administration of CA and dexamethasone exerted similar effects against hypoxic cerebral edema. The mechanism involved improving the integrity of the blood-brain-barrier, and inhibiting oxidative stress and inflammation.

ZO-1 expression is suppressed by GM-CSF via miR-96/ERG in brain microvascular endothelial cells

The level of granulocyte-macrophage colony-stimulating factor (GM-CSF) increases in some disorders such as vascular dementia, Alzheimer's disease, and multiple sclerosis. We previously reported that in Alzheimer's disease patients, a high level of GM-CSF in the brain parenchyma downregulated expression of ZO-1, a blood-brain barrier tight junction protein, and facilitated the infiltration of peripheral monocytes across the blood-brain barrier. However, the molecular mechanism underlying regulation of ZO-1 expression by GM-CSF is unclear. Herein, we found that the erythroblast transformation-specific (ETS) transcription factor ERG cooperated with the proto-oncogene protein c-MYC in regulation of ZO-1 transcription in brain microvascular endothelial cells (BMECs). The ERG expression was suppressed by miR-96 which was increased by GM-CSF through the phosphoinositide-3 kinase (PI3K)/Akt pathway. Inhibition of miR-96 prevented ZO-1 down-regulation induced by GM-CSF both in vitro and in vivo. Our results revealed the mechanism of ZO-1 expression reduced by GM-CSF, and provided a potential target, miR-96, which could block ZO-1 down-regulation caused by GM-CSF in BMECs.

Disruption of Intracellular ATP Generation and Tight Junction Protein Expression during the Course of Brain Edema Induced by Subacute Poisoning of 1,2-Dichloroethane

The aim of this study was to explore changes in intracellular ATP generation and tight junction protein expression during the course of brain edema induced by subacute poisoning of 1,2-dichloroethane (1,2-DCE). Mice were exposed to 1.2 g/m³ 1,2-DCE for 3.5 h per day for 1, 2, or 3 days, namely group A, B, and C. Na⁺-K⁺-ATPase and Ca²⁺-ATPase activity, ATP and lactic acid content, intracellular free Ca²⁺ concentration and ZO-1 and occludin expression in the brain were measured. Results of present study disclosed that Ca²⁺-ATPase activities in group B and C, and Na⁺/K⁺-ATPase activity in group C decreased, whereas intracellular free Ca²⁺ concentrations in group B and C increased significantly compared with control. Moreover, ATP content decreased, whereas lactic acid content increased significantly in group C compared with control. On the other hand, expressions of ZO-1 and occludin at both the protein and gene levels in group B and C decreased significantly compared with control. In conclusion, findings from this study suggest that calcium overload and depressed expression of tight junction associated proteins, such as ZO-1 and occludin might play an important role in the early phase of brain edema formation induced by subacute poisoning of 1,2-DCE.

Role of 3-Acetyl-11-Keto-Beta-Boswellic Acid in Counteracting LPS-Induced Neuroinflammation via Modulation of miRNA-155

Neuroinflammation is one of the most important mechanisms underlying neurodegeneration. Lipopolysaccharide (LPS) is a potent inflammogen which causes cognitive dysfunction. Boswellia serrata is known since many years as a powerful anti-inflammatory herbal drug. Its beneficial effect mainly arises from inhibition of 5-lipoxygenase (5-LO) enzyme. 3-acetyl-11-keto-β-boswellic acid (AKBA) is the most potent 5-LO inhibitor extracted from the oleo-gum-resin of Boswellia serrata. The aim of the present work is to study the molecular mechanisms underlying the anti-inflammatory and neuroprotective effects of AKBA and dexamethasone (DEX) in LPS-induced neuroinflammatory model. A single intraperitoneal (i.p.) dose of LPS (0.8 mg/kg) was injected to induce cognitive dysfunction. The LPS-treated mice were administered for 7 days with either AKBA or DEX at intraperitoneal doses of 5 and 1 mg/kg, respectively. Cognitive, locomotor functions, and anxiety level were first examined. The level of the phosphorylated inhibitory protein for NF-κB, IκB-α (P-IκB-α), was measured, and the expression levels of the inflammatory microRNA-155 (miR-155) and its target gene, suppressor of cytokine signaling-1 (SOCS-1), were determined in the brain. Moreover, the level of carbonyl proteins as a measure of oxidative stress and several cytokines as well as markers for apoptosis and amyloidogenesis was detected. Results showed that AKBA and DEX reversed the behavioral dysfunction induced by LPS. AKBA decreased P-IκB-α, miRNA-155 expression level, and carbonyl protein content. It restored normal cytokine level and increased SOCS-1 expression level. It also showed anti-apoptotic and anti-amyloidogenic effects in LPS-injected mice. These findings suggest AKBA as a therapeutic drug for alleviating the symptoms of neuroinflammatory disorders.

Neurocognitive profiles in MSUD school-age patients

Maple syrup urine disease (MSUD), an inborn error of amino acids catabolism is characterized by accumulation of branched chain amino acids (BCAAs) leucine, isoleucine, valine and their corresponding alpha-ketoacids. Impact on the cognitive development has been reported historically, with developmental delays of varying degree. Currently, earlier diagnosis and improved management allow a better neurodevelopment, without requirement of special education. However, specific impairments can be observed, and so far, results of detailed neurocognitive assessments are not available. The aim of this study was to analyse neurocognitive profiles of French MSUD patients. This was a multicentre retrospective study on MSUD patients who underwent neurocognitive evaluation at primary school age. Twenty-one patients with classical neonatal onset MSUD were included. The patients' mean age at the time of evaluation was 8.7 years. The mean intellectual quotient (IQ) score was in the normal range (95.1 ± 12.6). In a subset of eight patients, a consistent developmental pattern of higher verbal than performance IQ was observed (mean of the difference 25.7 ± 8.7, p < 0.0001). No correlation could be established between this pattern and long-term metabolic balance (BCAA blood levels), or severity of acute metabolic imbalances, or leucine blood levels at diagnosis and time to toxin removal procedure. These data show that some MSUD patients may exhibit an abnormal neurocognitive profile with higher verbal than performance abilities. This might suggest an executive dysfunction disorder that would need to be further investigated by specialized testing. This pattern is important to detect in MSUD, as appropriate neuropsychological treatment strategies should be proposed.

Serum Markers of Neurodegeneration in Maple Syrup Urine Disease

Maple syrup urine disease (MSUD) is an inherited disorder caused by deficient activity of the branched-chain α-keto acid dehydrogenase complex involved in the degradation pathway of branched-chain amino acids (BCAAs) and their respective α-keto-acids. Patients affected by MSUD present severe neurological symptoms and brain abnormalities, whose pathophysiology is poorly known. However, preclinical studies have suggested alterations in markers involved with neurodegeneration. Because there are no studies in the literature that report the neurodegenerative markers in MSUD patients, the present study evaluated neurodegenerative markers (brain-derived neurotrophic factor (BDNF), cathepsin D, neural cell adhesion molecule (NCAM), plasminogen activator inhibitor-1 total (PAI-1 (total)), platelet-derived growth factor AA (PDGF-AA), PDGF-AB/BB) in plasma from 10 MSUD patients during dietary treatment. Our results showed a significant decrease in BDNF and PDGF-AA levels in MSUD patients. On the other hand, NCAM and cathepsin D levels were significantly greater in MSUD patients compared to the control group, while no significant changes were observed in the levels of PAI-1 (total) and PDGF-AB/BB between the control and MSUD groups. Our data show that MSUD patients present alterations in proteins involved in the neurodegenerative process. Thus, the present findings corroborate previous studies that demonstrated that neurotrophic factors and lysosomal proteases may contribute, along with other mechanisms, to the intellectual deficit and neurodegeneration observed in MSUD.

Administration of branched-chain amino acids alters the balance between pro-inflammatory and anti-inflammatory cytokines

Acute leucine intoxication and neurologic deterioration can develop rapidly at any age as a result of net protein degradation precipitated by infection or psychological stress in patients with maple syrup urine disease (MSUD). Here, we investigated the effects of acute and chronic Hyper-BCAA (H-BCAA) administration on pro- and anti-inflammatory cytokines in the brains of rats. For acute administration, Wistar rats (10 and 30 days) received three injections of BCAA pool (15.8 μL/g at 1-h intervals) or saline, subcutaneously. For chronic administration, Wistar rats (7 days) received of BCAA pool or saline twice a day for 21 days, subcutaneously. Our results showed that acute administration of H-BCAA increased IL-1β (∼ 78%; p ≤ 0.009) and TNF-α (∼ 155%; p ≤ 0.026) levels in the cerebral cortex but not in the hippocampus of infant rats. Moreover, IL-6 levels were increased in the hippocampus (∼ 135%; p ≤ 0.009) and cerebral cortex (∼ 417%; p ≤ 0.008), whereas IL-10 levels were decreased only in the hippocampus (∼ 42%; p ≤ 0.009). However, repeated administration of H-BCAA decreased IL-1β (∼ 59%; p ≤ 0.047), IL-6 (∼ 70%; p ≤ 0.009) and IFN-γ (∼ 70%; p ≤ 0.008) levels in the cerebral cortex, whereas the IL-6 (∼ 67%; p ≤ 0.009), IL-10 (∼ 58%; p ≤ 0.01) and IFN-γ (∼ 67%; p ≤ 0.009) levels were decreased in the hippocampus. These findings suggest that a better understanding of the inflammatory response in MSUD patients may be useful to develop therapeutic strategies to modulate the hyperinflammatory/hypoinflammatory axis.