scholarly journals In vivo Monitoring of Cerebral Hemodynamics in the Immature Rat: Effects of Hypoxia-Ischemia and Hypothermia

2015 ◽  
Vol 37 (4-5) ◽  
pp. 407-416 ◽  
Author(s):  
Erin M. Buckley ◽  
Shyama D. Patel ◽  
Benjamin F. Miller ◽  
Maria Angela Franceschini ◽  
Susan J. Vannucci
Keyword(s):  
Cerebral Metabolism ◽  
Correlation Spectroscopy ◽  
Ordinal Scale ◽  
Cerebral Damage ◽  
Artery Ligation ◽  
Rat Pups ◽  
Baseline Levels ◽  
Term Births ◽  
Unanesthetized Animals

Background: Neonatal hypoxic-ischemic (HI) encephalopathy occurs in 1-4 per 1,000 live term births and can cause devastating neurodevelopmental disabilities. Currently, therapeutic hypothermia (TH) is the only treatment with proven efficacy. Since TH is associated with decreased cerebral metabolism and cerebral blood flow (CBF), it is important to assess CBF at the bedside. Diffuse correlation spectroscopy (DCS) has emerged as a promising optical modality to noninvasively assess an index of CBF (CBFi) in both humans and animals. In this initial descriptive study, we employ DCS to monitor the evolution of CBFi following HI with or without TH in immature rats. We investigate potential relationships between CBF and subsequent cerebral damage. Methods: HI was induced on postnatal day 10 or 11 rat pups by right common carotid artery ligation followed by 60-70 min hypoxia (8% oxygen). After HI, the pups recovered for 4 h under hypothermia (HI-TH group, n = 23) or normothermia (HI-N group, n = 23). Bilateral measurements of hemispheric CBFi were made with DCS in unanesthetized animals at baseline, before HI, and 0, 1, 2, 3, 4, 5, and 24 h after HI. The animals were sacrificed at either 1 or 4 weeks, and brain injury was scored on an ordinal scale of 0-5 (0 = no injury). Results: Carotid ligation caused moderate bilateral decreases in CBFi. Following HI, an initial hyperemia was observed that was more prominent in the contralateral hemisphere. After initiation of TH, CBFi dropped significantly below baseline levels and remained reduced for the duration of TH. In contrast, CBFi in the HI-N group was not significantly decreased from baseline levels. Reductions in CBFi after 4 h of TH were not associated with reduced damage at 1 or 4 weeks. However, elevated ipsilateral CBFi and ipsilateral-to-contralateral CBFi ratios at 24 h were associated with worse outcome at 1 week after HI. Conclusions: Both HI and TH alter CBFi, with significant differences in CBFi between hypothermic and normothermic groups after HI. CBFi may be a useful biomarker of subsequent cerebral damage.

scholarly journals The neurochemical profile of the hippocampus in isoflurane-treated and unanesthetized rat pups

2015 ◽  
Vol 8 (3) ◽  
pp. 113-117 ◽  
Author(s):  
Petr N. Menshanov ◽  
Andrey E. Akulov
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cerebral Metabolism ◽  
Resonance Spectroscopy ◽  
Neonatal Rats ◽  
Resonance Imaging ◽  
Rat Pups ◽  
Neurochemical Profile ◽  
Inhaled Anesthetic

Abstract In vivo study of cerebral metabolism in neonatal animals by high-resolution magnetic resonance spectroscopy (MRS) is an important tool for deciphering the developmental origins of adult diseases. Up to date, all in vivo spectrum acquisition procedures have been performed in neonatal rodents under anesthesia. However, it is still unknown if the inhaled anesthetic isoflurane, which is commonly used in magnetic resonance imaging studies, could affect metabolite levels in the brain of neonatal rats. Moreover, the unanesthetized MRS preparation that uses neonatal rodent pups is still lacking. Here, a novel restraint protocol was developed for neonatal rats in accordance with the European Directive 2010/63/EU. This protocol shares the same gradation of severity as the protocol for non-invasive magnetic resonance imaging of animals with appropriate sedation or anesthesia. Such immobilization of neonatal rats without anesthesia can be implemented for MRS studies when an interaction between anesthetic and target drugs is expected. Short-term isoflurane treatment did not affect the levels of key metabolites in the hippocampi of anesthetized pups and, in contrast to juvenile and adult rodents, it is suitable for MRS studies in neonatal rats when the interaction between anesthetic and target drugs is not expected.

scholarly journals The Effect of Hyperglycemia on Cerebral Metabolism during Hypoxia-Ischemia in the Immature Rat

1996 ◽  
Vol 16 (5) ◽  
pp. 1026-1033 ◽  
Author(s):  
Robert C. Vannucci ◽  
Robert M. Brucklacher ◽  
Susan J. Vannucci
Keyword(s):  
Cerebral Metabolism ◽  
Glycolytic Flux ◽  
Artery Ligation ◽  
Immature Rat ◽  
Ischemic Brain ◽  
Glucose Levels ◽  
Rat Pups ◽  
Carotid Artery Ligation ◽  
Hypoxia Ischemia ◽  
Blood Glucose Concentrations

Unlike adults, hyperglycemia with circulating glucose concentrations of 25–35 m M/L protects the immature brain from hypoxic–ischemic damage. To ascertain the effect of hyperglycemia on cerebral oxidative metabolism during the course of hypoxia–ischemia, 7-day postnatal rats underwent unilateral common carotid artery ligation followed by exposure to 8% O2 for 2 h at 37°C. Experimental animals received 0.2 cc s.c. 50% glucose at the onset of hypoxia–ischemia, and 0.15 cc 25% glucose 1 h later to maintain blood glucose concentrations at 20–25 m ML for 2 h. Control rat pups received equivalent concentrations or volumes of either mannitol or 1 N saline at the same intervals. The cerebral metabolic rate for glucose (CMRglc.) increased from 7.1 (control) to 20.2 μmol 100 g−1 min−1 in hyperglycemic rats during the first hour of hypoxia–ischemia, 79 and 35% greater than the rates for saline- and mannitol-injected animals at the same interval, respectively ( p < 0.01). Brain intracellular glucose concentrations were 5.2 and 3.0 m M/kg in the hyperglycemic rat pups at 1 and 2 h of hypoxia–ischemia, respectively; glucose levels were near negligible in mannitol- and saline-treated animals at the same intervals. Brain intracellular lactate concentrations averaged 13.4 and 23.3 m M/kg in hyperglycemic animals at 1 and 2 h of hypoxia–ischemia, respectively, more than twice the concentrations estimated for the saline- and mannitol-treated littermates. Phosphocreatine (PCr) and ATP decreased in all three experimental groups, but were preserved to the greatest extent in hyperglycemic animals. Results indicate that anaerobic glycolytic flux is increased to a greater extent in hyperglycemic immature rats than in normoglycemic littermates subjected to cerebral hypoxia–ischemia, and that the enhanced glycolysis leads to greater intracellular lactate accumulation. Despite cerebral lactosis, energy reserves were better preserved in hyperglycemic animals than in saline-treated controls, thus accounting for the greater resistance of hyperglycemic animals to hypoxic–ischemic brain damage.

2D NMR studies on muscle and cerebral metabolism in vivo

1994 ◽  
Vol 91 ◽  
pp. 697-703 ◽  
Author(s):  
B Gillet ◽  
BT Doan ◽  
C Verre-Sebrie ◽  
O Fedeli ◽  
JC Beloeil ◽  
...  
Keyword(s):  
Cerebral Metabolism ◽  
2D Nmr ◽  
Nmr Studies

scholarly journals Degradation of Drug Delivery Nanocarriers and Payload Release: A Review of Physical Methods for Tracing Nanocarrier Biological Fate

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 770
Author(s):  
Patrick M. Perrigue ◽  
Richard A. Murray ◽  
Angelika Mielcarek ◽  
Agata Henschke ◽  
Sergio E. Moya
Keyword(s):  
Drug Delivery ◽  
Laser Scanning ◽  
Single Photon ◽  
Photon Emission ◽  
Correlation Spectroscopy ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Emission Computed Tomography ◽  
Systemic Delivery

Nanoformulations offer multiple advantages over conventional drug delivery, enhancing solubility, biocompatibility, and bioavailability of drugs. Nanocarriers can be engineered with targeting ligands for reaching specific tissue or cells, thus reducing the side effects of payloads. Following systemic delivery, nanocarriers must deliver encapsulated drugs, usually through nanocarrier degradation. A premature degradation, or the loss of the nanocarrier coating, may prevent the drug’s delivery to the targeted tissue. Despite their importance, stability and degradation of nanocarriers in biological environments are largely not studied in the literature. Here we review techniques for tracing the fate of nanocarriers, focusing on nanocarrier degradation and drug release both intracellularly and in vivo. Intracellularly, we will discuss different fluorescence techniques: confocal laser scanning microscopy, fluorescence correlation spectroscopy, lifetime imaging, flow cytometry, etc. We also consider confocal Raman microscopy as a label-free technique to trace colocalization of nanocarriers and drugs. In vivo we will consider fluorescence and nuclear imaging for tracing nanocarriers. Positron emission tomography and single-photon emission computed tomography are used for a quantitative assessment of nanocarrier and payload biodistribution. Strategies for dual radiolabelling of the nanocarriers and the payload for tracing carrier degradation, as well as the efficacy of the payload delivery in vivo, are also discussed.

scholarly journals Umbilical cord blood therapy modulates neonatal hypoxic ischemic brain injury in both females and males

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tayla R. Penny ◽  
Yen Pham ◽  
Amy E. Sutherland ◽  
Joohyung Lee ◽  
Graham Jenkin ◽  
...  
Keyword(s):  
Brain Injury ◽  
Cord Blood ◽  
Umbilical Cord ◽  
Umbilical Cord Blood ◽  
Significant Risk ◽  
Immunohistochemical Analysis ◽  
Significant Risk Factor ◽  
Tissue Loss ◽  
Artery Ligation ◽  
Rat Pups

AbstractPreclinical and clinical studies have shown that sex is a significant risk factor for perinatal morbidity and mortality, with males being more susceptible to neonatal hypoxic ischemic (HI) brain injury. No study has investigated sexual dimorphism in the efficacy of umbilical cord blood (UCB) cell therapy. HI injury was induced in postnatal day 10 (PND10) rat pups using the Rice-Vannucci method of carotid artery ligation. Pups received 3 doses of UCB cells (PND11, 13, 20) and underwent behavioural testing. On PND50, brains were collected for immunohistochemical analysis. Behavioural and neuropathological outcomes were assessed for sex differences. HI brain injury resulted in a significant decrease in brain weight and increase in tissue loss in females and males. Females and males also exhibited significant cell death, region-specific neuron loss and long-term behavioural deficits. Females had significantly smaller brains overall compared to males and males had significantly reduced neuron numbers in the cortex compared to females. UCB administration improved multiple aspects of neuropathology and functional outcomes in males and females. Females and males both exhibited injury following HI. This is the first preclinical evidence that UCB is an appropriate treatment for neonatal brain injury in both female and male neonates.

scholarly journals NAC and Vitamin D Restore CNS Glutathione in Endotoxin-Sensitized Neonatal Hypoxic-Ischemic Rats

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 489
Author(s):  
Lauren E. Adams ◽  
Hunter G. Moss ◽  
Danielle W. Lowe ◽  
Truman Brown ◽  
Donald B. Wiest ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Vitamin D ◽  
Redox Status ◽  
Therapeutic Window ◽  
Post Injury ◽  
Artery Ligation ◽  
Cellular Redox ◽  
Carotid Artery Ligation ◽  
Drug Concentrations

Therapeutic hypothermia does not improve outcomes in neonatal hypoxia ischemia (HI) complicated by perinatal infection, due to well-described, pre-existing oxidative stress and neuroinflammation that shorten the therapeutic window. For effective neuroprotection post-injury, we must first define and then target CNS metabolomic changes immediately after endotoxin-sensitized HI (LPS-HI). We hypothesized that LPS-HI would acutely deplete reduced glutathione (GSH), indicating overwhelming oxidative stress in spite of hypothermia treatment in neonatal rats. Post-natal day 7 rats were randomized to sham ligation, or severe LPS-HI (0.5 mg/kg 4 h before right carotid artery ligation, 90 min 8% O2), followed by hypothermia alone or with N-acetylcysteine (25 mg/kg) and vitamin D (1,25(OH)2D3, 0.05 μg/kg) (NVD). We quantified in vivo CNS metabolites by serial 7T MR Spectroscopy before, immediately after LPS-HI, and after treatment, along with terminal plasma drug concentrations. GSH was significantly decreased in all LPS-HI rats compared with baseline and sham controls. Two hours of hypothermia alone did not improve GSH and allowed glutamate + glutamine (GLX) to increase. Within 1 h of administration, NVD increased GSH close to baseline and suppressed GLX. The combination of NVD with hypothermia rapidly improved cellular redox status after LPS-HI, potentially inhibiting important secondary injury cascades and allowing more time for hypothermic neuroprotection.

scholarly journals An investigation of arterial insufficiency in the rat hindlimb Correlation of skeletal muscle bloodflow and glucose utilization in vivo

1986 ◽  
Vol 240 (2) ◽  
pp. 395-401 ◽  
Author(s):  
R A Challiss ◽  
D J Hayes ◽  
G K Radda
Keyword(s):  
Skeletal Muscle ◽  
Sciatic Nerve ◽  
Glucose Uptake ◽  
Nerve Stimulation ◽  
Linear Correlation ◽  
Glucose Utilization ◽  
Fold Increase ◽  
Artery Ligation ◽  
Sciatic Nerve Stimulation

Muscle bloodflow and the rate of glucose uptake and phosphorylation were measured in vivo in rats 7 days after unilateral femoral artery ligation and section. Bloodflow was determined by using radiolabelled microspheres. At rest, bloodflow to the gastrocnemius, plantaris and soleus muscles of the ligated limb was similar to their respective mean contralateral control values; however, bilateral sciatic nerve stimulation at 1 Hz caused a less pronounced hyperaemic response in the muscles of the ligated limb, being 59, 63 and 49% of their mean control values in the gastrocnemius, plantaris and soleus muscles respectively. The rate of glucose utilization was determined by using the 2-deoxy[3H]glucose method [Ferré, Leturque, Burnol, Penicaud & Girard (1985) Biochem. J. 228, 103-110]. At rest, the rate of glucose uptake and phosphorylation was statistically significantly increased in the gastrocnemius and soleus muscles of the ligated limb, being 126 and 140% of the mean control values respectively. Bilateral sciatic nerve stimulation at 1 Hz caused a 3-5-fold increase in the rate of glucose utilization by the ligated and contralateral control limbs; furthermore, the rate of glucose utilization was significantly increased in the muscles of the ligated limb, being 140, 129 and 207% of their mean control values respectively. For the range of bloodflow to normally perfused skeletal muscle at rest or during isometric contraction determined in the present study, a linear correlation between the rate of glucose utilization and bloodflow can be demonstrated. Applying similar methods of regression analysis to glucose utilization and bloodflow to muscles of the ligated limb reveals a similar linear correlation. However, the rate of glucose utilization at a given bloodflow is increased in muscles of the ligated limb, indicating an adaptation of skeletal muscle to hypoperfusion.

scholarly journals Inhibitory Effect of a Glutamine Antagonist on Proliferation and Migration of VSMCs via Simultaneous Attenuation of Glycolysis and Oxidative Phosphorylation

2021 ◽  
Vol 22 (11) ◽  
pp. 5602
Author(s):  
Hyeon Young Park ◽  
Mi-Jin Kim ◽  
Seunghyeong Lee ◽  
Jonghwa Jin ◽  
Sungwoo Lee ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
Inhibitory Effect ◽  
Metabolic Reprogramming ◽  
Neointima Formation ◽  
Artery Ligation ◽  
Carotid Artery Ligation ◽  
And Migration ◽  
Proliferation And Migration

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs) contribute to the development of atherosclerosis and restenosis. Glycolysis and glutaminolysis are increased in rapidly proliferating VSMCs to support their increased energy requirements and biomass production. Thus, it is essential to develop new pharmacological tools that regulate metabolic reprogramming in VSMCs for treatment of atherosclerosis. The effects of 6-diazo-5-oxo-L-norleucine (DON), a glutamine antagonist, have been broadly investigated in highly proliferative cells; however, it is unclear whether DON inhibits proliferation of VSMCs and neointima formation. Here, we investigated the effects of DON on neointima formation in vivo as well as proliferation and migration of VSMCs in vitro. DON simultaneously inhibited FBS- or PDGF-stimulated glycolysis and glutaminolysis as well as mammalian target of rapamycin complex I activity in growth factor-stimulated VSMCs, and thereby suppressed their proliferation and migration. Furthermore, a DON-derived prodrug, named JHU-083, significantly attenuated carotid artery ligation-induced neointima formation in mice. Our results suggest that treatment with a glutamine antagonist is a promising approach to prevent progression of atherosclerosis and restenosis.

Active protein transport through plastid tubules: velocity quantified by fluorescence correlation spectroscopy

2000 ◽  
Vol 113 (22) ◽  
pp. 3921-3930 ◽  
Author(s):  
R.H. Kohler ◽  
P. Schwille ◽  
W.W. Webb ◽  
M.R. Hanson
Keyword(s):  
Active Transport ◽  
Fluorescence Correlation Spectroscopy ◽  
Protein Transport ◽  
Fluorescent Protein ◽  
Correlation Spectroscopy ◽  
Long Distance ◽  
Fluorescence Correlation ◽  
Photon Excitation ◽  
Green Fluorescent

Dynamic tubular projections emanate from plastids in certain cells of vascular plants and are especially prevalent in non-photosynthetic cells. Tubules sometimes connect two or more different plastids and can extend over long distances within a cell, observations that suggest that the tubules may function in distribution of molecules within, to and from plastids. In a new application of two-photon excitation (2PE) fluorescence correlation spectroscopy (FCS), we separated diffusion of fluorescent molecules from active transport in vivo. We quantified the velocities of diffusion versus active transport of green fluorescent protein (GFP) within plastid tubules and in the cytosol in vivo. GFP moves by 3-dimensional (3-D) diffusion both in the cytosol and plastid tubules, but diffusion in tubules is about 50 times and 100 times slower than in the cytosol and an aqueous solution, respectively. Unexpectedly larger GFP units within plastid tubules exhibited active transport with a velocity of about 0.12 microm/second. Active transport might play an important role in the long-distance distribution of large numbers of molecules within the highly viscous stroma of plastid tubules.

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