Lili Miles

High-fructose, medium chain trans fat diet induces liver fibrosis and elevates plasma coenzyme Q9 in a novel murine model of obesity and nonalcoholic steatohepatitis†

Diets high in saturated fat and fructose have been implicated in the development of obesity and nonalcoholic steatohepatitis (NASH) in humans. We hypothesized that mice exposed to a similar diet would develop NASH with fibrosis associated with increased hepatic oxidative stress that would be further reflected by increased plasma levels of the respiratory chain component, oxidized coenzyme Q9 (oxCoQ9). Adult male C57Bl/6 mice were randomly assigned to chow, high‐fat (HF), or high‐fat high‐carbohydrate (HFHC) diets for 16 weeks. The chow and HF mice had free access to pure water, whereas the HFHC group received water with 55% fructose and 45% sucrose (wt/vol). The HFHC and HF groups had increased body weight, body fat mass, fasting glucose, and were insulin‐resistant compared with chow mice. HF and HFHC consumed similar calories. Hepatic triglyceride content, plasma alanine aminotransferase, and liver weight were significantly increased in HF and HFHC mice compared with chow mice. Plasma cholesterol (P < 0.001), histological hepatic fibrosis, liver hydroxyproline content (P = 0.006), collagen 1 messenger RNA (P = 0.003), CD11b‐F4/80+Gr1+ monocytes (P < 0.0001), transforming growth factor β1 mRNA (P = 0.04), and α‐smooth muscle actin messenger RNA (P = 0.001) levels were significantly increased in HFHC mice. Hepatic oxidative stress, as indicated by liver superoxide expression (P = 0.002), 4‐hydroxynonenal, and plasma oxCoQ9 (P < 0.001) levels, was highest in HFHC mice. Conclusion: These findings demonstrate that nongenetically modified mice maintained on an HFHC diet in addition to developing obesity have increased hepatic ROS and a NASH‐like phenotype with significant fibrosis. Plasma oxCoQ9 correlated with fibrosis progression. The mechanism of fibrosis may involve fructose inducing increased ROS associated with CD11b+F4/80+Gr1+ hepatic macrophage aggregation, resulting in transforming growth factor β1–signaled collagen deposition and histologically visible hepatic fibrosis. (HEPATOLOGY 2010)

The effects of neonatal isoflurane exposure in mice on brain cell viability, adult behavior, learning, and memory.

BACKGROUND: Volatile anesthetics, such as isoflurane, are widely used in infants and neonates. Neurodegeneration and neurocognitive impairment after exposure to isoflurane, midazolam, and nitrous oxide in neonatal rats have raised concerns regarding the safety of pediatric anesthesia. In neonatal mice, prolonged isoflurane exposure triggers hypoglycemia, which could be responsible for the neurocognitive impairment. We examined the effects of neonatal isoflurane exposure and blood glucose on brain cell viability, spontaneous locomotor activity, as well as spatial learning and memory in mice. METHODS: Seven-day-old mice were randomly assigned to 6 h of 1.5% isoflurane with or without injections of dextrose or normal saline, or to 6 h of room air without injections (no anesthesia). Arterial blood gases and glucose were measured. After 2 h, 18 h, or 11 wk postexposure, cellular viability was assessed in brain sections stained with Fluoro-Jade B, caspase 3, or NeuN. Nine weeks postexposure, spontaneous locomotor activity was assessed, and spatial learning and memory were evaluated in the Morris water maze using hidden and reduced platform trials. RESULTS: Apoptotic cellular degeneration increased in several brain regions early after isoflurane exposure, compared with no anesthesia. Despite neonatal cell loss, however, adult neuronal density was unaltered in two brain regions significantly affected by the neonatal degeneration. In adulthood, spontaneous locomotor activity and spatial learning and memory performance were similar in all groups, regardless of neonatal isoflurane exposure. Neonatal isoflurane exposure led to an 18% mortality, and transiently increased Paco2, lactate, and base deficit, and decreased blood glucose levels. However, hypoglycemia did not seem responsible for the neurodegeneration, as dextrose supplementation failed to prevent neuronal loss. CONCLUSIONS: Prolonged isoflurane exposure in neonatal mice led to increased immediate brain cell degeneration, however, no significant reductions in adult neuronal density or deficits in spontaneous locomotion, spatial learning, or memory function were observed.

Multimodality imaging in the surgical treatment of children with nonlesional epilepsy

Objectives: To evaluate the diagnostic value of individual noninvasive presurgical modalities and to study their role in surgical management of nonlesional pediatric epilepsy patients. Methods: We retrospectively studied 14 children (3–18 years) with nonlesional intractable focal epilepsy. Clinical characteristics, surgical outcome, localizing features on 3 presurgical diagnostic tests (subtraction peri-ictal SPECT coregistered to MRI [SISCOM], statistical parametric mapping [SPM] analysis of [18F] FDG-PET, magnetoencephalography [MEG]), and intracranial EEG (iEEG) were reviewed. The localization of each individual test was determined for lobar location by visual inspection. Concordance of localization between each test and iEEG was scored as follows: 2 = lobar concordance; 1 = hemispheric concordance; 0 = discordance or nonlocalization. Total concordance score in each patient was measured by the summation of concordance scores for all 3 tests. Results: Seven (50%) of 14 patients were seizure-free for at least 12 months after surgery. One (7%) had only rare seizures and 6 (43%) had persistent seizures. MEG (79%, 11/14) and SISCOM (79%, 11/14) showed greater lobar concordance with iEEG than SPM-PET (13%, 3/14) (p < 0.05). SPM-PET provided hemispheric lateralization (71%, 10/14) more often than lobar localization. Total concordance score tended to be greater for seizure-free patients (4.7) than for non–seizure-free patients (3.9). Conclusions: Our data suggest that MEG and SISCOM are better tools for lobar localization than SPM analysis of FDG-PET in children with nonlesional epilepsy. A multimodality approach may improve surgical outcome as well as selection of surgical candidates in patients without MRI abnormalities.

Histologic Spectrum of Nonalcoholic Fatty Liver Disease in Morbidly Obese Adolescents

BACKGROUND & AIMS To characterize the spectrum of nonalcoholic fatty liver disease (NAFLD) in morbidly obese adolescents, we correlated liver histology with clinical features and compared findings with reported adult data. We hypothesized that NAFLD would be less severe as a result of younger age and shorter duration of obesity, but portal inflammation and fibrosis would be more prevalent. METHODS Cross-sectional study was made of 41 adolescent subjects, 13-19 years old (mean, 16 years), 61% female, 83% non-Hispanic white, mean body mass index 59 kg/m(2), undergoing gastric bypass with liver biopsy. Liver biopsies were graded and staged as proposed by the NASH Clinical Research Network. Data were analyzed by using descriptive statistics, analysis of variance, and Fisher exact tests. RESULTS Eighty-three percent had NAFLD: 24% steatosis alone, 7% isolated fibrosis with steatosis, 32% nonspecific inflammation and steatosis, and 20% nonalcoholic steatohepatitis (NASH). Twenty-nine percent had fibrosis; none had cirrhosis. Abnormal ALT (P = .05) and AST (P = .01) were more prevalent in NASH. Mean fasting glucose was significantly higher in NASH (P = .05), but prevalence of the metabolic syndrome was not significantly different. CONCLUSIONS NAFLD was very prevalent in morbidly obese adolescents, but severe NASH was uncommon. In contrast to morbidly obese adults, lobular inflammation, significant ballooning, and perisinusoidal fibrosis were rare, whereas portal inflammation and portal fibrosis were more prevalent, even in those who did not meet criteria for NASH. These findings might support use of a modified scoring system for pediatric NASH. Presence of the metabolic syndrome in morbidly obese adolescents did not distinguish NASH from steatosis alone.

Cerebral oxygen saturation-time threshold for hypoxic-ischemic injury in piglets.

BACKGROUND: Detection of cerebral hypoxia-ischemia (H-I) and prevention of brain injury remains problematic in critically ill neonates. Near-infrared spectroscopy (NIRS), a noninvasive bedside technology could fill this role, although NIRS cerebral O2 saturation (ScO2) viability-time thresholds for brain injury have not been determined. We investigated the relationship between H-I duration at ScO2 35%, a viability threshold which causes neurophysiological impairment, to neurological outcome. METHODS: Forty-six fentanyl-midazolam anesthetized piglets were equipped with NIRS and cerebral function monitor (CFM) to record ScO2 and electrocortical activity (ECA). After carotid occlusion, inspired O2 was adjusted to produce H-I (ScO2 35% with decreased ECA) for 1, 2, 3, 4, 6 or 8 h in different groups, followed by survival to assess neurological outcome by behavioral and histological examination. RESULTS: For H-I lasting 1 or 2 h, ECA and ScO2 during reperfusion rapidly returned to normal and neurological outcomes were normal. For H-I more than 2–3 h, ECA was significantly decreased and ScO2 was significantly increased during reperfusion, suggesting continued depression of tissue O2 metabolism. As H-I increased beyond 2 h, the incidence of neurological injury increased linearly, approximately 15% per h. CONCLUSION: A viability-time threshold for H-I injury is ScO2 of 35% for 2–3 h, heralded by abnormalities in NIRS and CFM during reperfusion. These findings suggest that NIRS and CFM might be used together to predict neurological outcome, and illustrate that there is a several hour window of opportunity during H-I to prevent neurological injury.

Use of Magnetic Resonance Elastography to Assess Hepatic Fibrosis in Children with Chronic Liver Disease

Management of pediatric chronic liver disease is limited by lack of validated noninvasive biomarkers of histologic severity. We demonstrate that magnetic resonance elastography is feasible and accurate in detecting significant hepatic fibrosis in a case series of 35 children with chronic liver disease, including severely obese children.

Desflurane, isoflurane, and sevoflurane provide limited neuroprotection against neonatal hypoxia-ischemia in a delayed preconditioning paradigm.

Background:The volatile anesthetics desflurane, isofluorane, and sevoflurane have been found to produce neuroprotection in various paradigms. The authors used these agents in a delayed preconditioning model to test the hypothesis that they could provide neuroprotection against neonatal hypoxia-ischemia as assessed by a battery of behavioral tests. Methods:Institutional Animal Care and Use Committee approval was obtained. A total of 140, C57-129T2 F1 hybrid 9-day-old mice were randomized to 3 h of preconditioning with room air (Group Sham and Group HI), 8.4% desflurane in 40% oxygen (Group D), 1.8% isoflurane (Group I), or 3.1% sevoflurane (Group S). Twenty-four hours later, the Group HI, D, I, and S mice had 60 min of hypoxia-ischemia, and Group Sham had 60 min of sham HI. Surviving animals had behavioral testing, including open field activity, acoustic startle, prepulse inhibition, rotorod, novel object recognition, water mazes, and apomorphine challenge. Histologic analysis was also performed. Results:Mice in Groups D, I, and S performed better than Group HI and similarly to Group Sham on novel object recognition and apomorphine challenge and better than Group HI but not as well as Group Sham on cued maze testing. All mice exposed to hypoxia-ischemia performed worse than Group Sham on the spatially oriented water mazes with no difference among groups. Histologic sections did not show any significant effect of preconditioning on injury scores. Conclusions:Volatile agent preconditioning partially protects perirhinal cortex and striatal dependent functions against moderate to severe neonatal hypoxia-ischemia.

Mixed lineage kinase 3 deficient mice are protected against the high fat high carbohydrate diet-induced steatohepatitis

C‐Jun N‐terminal kinase (JNK) activation is pivotal in the development of nonalcoholic steatohepatitis (NASH). Mixed lineage kinase 3 (MLK) 3 is one of the mitogen activated protein kinase kinase kinase (MAP3K) that mediates JNK activation in the liver. Despite this concept, the role of MLK3 in modulating liver injury during nutrient excess has not been explored. Our aim was to determine if MLK3 deficient mice were protected against high fat high carbohydrate (HFHC) diet‐induced NASH.

Prognostic significance of telomere maintenance mechanisms in pediatric high-grade gliomas

Children with high-grade glioma, including diffuse intrinsic pontine glioma (DIPG), have a poor prognosis despite multimodal therapy. Identifying novel therapeutic targets is critical to improve their outcome. We evaluated prognostic roles of telomere maintenance mechanisms in children with HGG, including DIPG. A multi-institutional retrospective study was conducted involving 50 flash-frozen HGG (35 non-brainstem; 15 DIPG) tumors from 45 children (30 non-brainstem; 15 DIPG). Telomerase activity, expression of hTERT mRNA (encoding telomerase catalytic component) and TERC (telomerase RNA template) and alternative lengthening of telomeres (ALT) mechanism were assayed. Cox Proportional Hazard regression analyses assessed association of clinical and pathological variables, TERC and hTERT levels, telomerase activity, and ALT use with progression-free or overall survival (OS). High TERC and hTERT expression was detected in 13/28 non-brainstem HGG samples as compared to non-neoplastic controls. High TERC and hTERT expression was identified in 13/15 and 11/15 DIPG samples, respectively, compared to controls. Evidence of ALT was noted in 3/11 DIPG and 10/19 non-brainstem HGG specimens. ALT and telomerase use were identified in 4/19 non-brainstem HGG and 2/11 DIPG specimens. In multivariable analyses, increased TERC and hTERT levels were associated with worse OS in patients with non-brainstem HGG, after controlling for tumor grade or resection extent. Children with HGG and DIPG, have increased hTERT and TERC expression. In children with non-brainstem HGG, increased TERC and hTERT expression levels are associated with a worse OS, making telomerase a promising potential therapeutic target in pediatric HGG.

Expression of glypican-3 in undifferentiated embryonal sarcoma and mesenchymal hamartoma of the liver.

Glypican-3 (GPC3) is an oncofetal protein that has been demonstrated to be a useful diagnostic immunomarker for hepatocellular carcinoma and hepatoblastoma. Its expression in mesenchymal tumors of the liver, particularly undifferentiated embryonal sarcoma (UES) and mesenchymal hamartoma (MH), has not been investigated. In this study, a total of 24 UESs and 18 MHs were immunohistochemically stained for GPC3 expression. The results showed cytoplasmic staining for GPC3 in 14 (58%) UESs, of which 6 exhibited diffuse immunoreactivity and the remaining 8 showed focal positivity. The patients with GPC3-positive UES tended to be younger (mean 18 years; median 11 years) than those with GPC3-negative tumors (mean 39.4 years; median 27 years), although the difference did not reach statistical significance (P = .06). Eight MHs also exhibited GPC3 immunoreactivity (44%; 4 diffuse and 4 focal). Positive staining in all 8 cases was primarily seen in entrapped nonlesional hepatocytes with a canalicular and cytoplasmic staining pattern. In only 4 cases (22%) was GPC3 immunoreactivity also observed in the mesenchymal component. The patients with positive staining also tended to be younger (mean 2.6 years; median 1.1 years) compared with those with negative staining (mean 16.3 years; median 4.5 years), but the difference was not statistically significant (P = .15). Our data demonstrate that GPC3 is expressed in a subset of UES and MH of the liver. Caution should thus be exercised when evaluating a GPC3-expressing hepatic neoplasm, particularly on a needle biopsy when the differential diagnosis includes poorly differentiated hepatocellular carcinoma or hepatoblastoma.