Peter H. Tang

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)

Bioequivalence of coenzyme Q10 from over-the-counter supplements

Abstract The objective of this study was to compare the relative bioavailability of two new products with solubilized and non-solubilized over-the-counter (OTC) coenzyme Q 10 products. Nine healthy adults were given single 180 mg doses of each coenzyme Q 10 formulation at two week intervals. A commercially-marketed, non-solubilized Q 10 powder formulation (product D) was only minimally absorbed, and was excluded from the analysis of data. ANOVA comparison of maximum plasma concentrations (C max ), time of maximum concentrations (t max ), areas under the concentration-time curves from times zero to 144 hours post dose (AUC 0-144h ), and areas under the concentration-time curves from times zero to infinity (AUC 0-∞ ) were not significantly different ( P > 0.05) between test products A (LiQ-10™) and B (Q-Nol™) and the reference product C (UbiQGel®). The upper limits of the 90% confidence intervals of the log-transformed ratios (A:C and B:C) of C max, AUC 0-144h, and AUC 0-∞ were >1.25 for both test products, but significant ( P 0-144h. The results of this study indicate that LiQ-10™ has increased bioequivalence compared to the reference product, but did not reach statistical significance. Q-Nol™ has increased bioavailability compared to the reference product ( P

Ubiquinone (coenzyme Q10) prevents renal mitochondrial dysfunction in an experimental model of type 2 diabetes

Cardiovascular benefits of ubiquinone have been previously demonstrated, and we administered it as a novel therapy in an experimental model of type 2 diabetic nephropathy. db/db and dbH mice were followed for 10 weeks, after randomization to receive either vehicle or ubiquinone (CoQ10; 10mg/kg/day) orally. db/db mice had elevated urinary albumin excretion rates and albumin:creatinine ratio, not seen in db/db CoQ10-treated mice. Renal cortices from db/db mice had lower total and oxidized CoQ10 content, compared with dbH mice. Mitochondria from db/db mice also contained less oxidized CoQ10(ubiquinone) compared with dbH mice. Diabetes-induced increases in total renal collagen but not glomerulosclerosis were significantly decreased with CoQ10 therapy. Mitochondrial superoxide and ATP production via complex II in the renal cortex were increased in db/db mice, with ATP normalized by CoQ10. However, excess renal mitochondrial hydrogen peroxide production and increased mitochondrial membrane potential seen in db/db mice were attenuated with CoQ10. Renal superoxide dismutase activity was also lower in db/db mice compared with dbH mice. Our results suggest that a deficiency in mitochondrial oxidized CoQ10 (ubiquinone) may be a likely precipitating factor for diabetic nephropathy. Therefore CoQ10 supplementation may be renoprotective in type 2 diabetes, via preservation of mitochondrial function.

Plasma coenzyme Q10 reference intervals, but not redox status, are affected by gender and race in self-reported healthy adults.

BACKGROUND Abnormal concentrations of coenzyme Q(10) have been reported in many patient groups, including certain cardiovascular, neurological, hematological, neoplastic, renal, and metabolic diseases. However, controls in these studies are often limited in number, poorly screened, and inadequately evaluated statistically. The purpose of this study is to determine the reference intervals of plasma concentrations of ubiquinone-10, ubiquinol-10, and total coenzyme Q(10) for self-reported healthy adults. METHODS Adults (n=148), who were participants in the Princeton Prevalence Follow-up Study, were identified as healthy by questionnaire. Lipid profiles, ubiquinone-10, ubiquinol-10, and total coenzyme Q(10) concentrations were measured in plasma. The method used to determine the reference intervals is a procedure incorporating outlier detection followed by robust point estimates of the appropriate quantiles. RESULTS Significant differences between males and females were present for ubiquinol-10 and total coenzyme Q(10). Blacks had significantly higher Q(10) measures than whites in all cases except for the ubiquinol-10/total Q(10) fraction. CONCLUSIONS The fraction of ubiquinol-10/total coenzyme Q(10) is a tightly regulated measure in self-reported healthy adults, and is independent of sex and racial differences. Different reference intervals for certain coenzyme Q(10) measures may need to be established based upon sex and racial characteristics.

An improved gas chromatography assay for topiramate monitoring in pediatric patients.

An improved micromethod involving capillary gas chromatographic assay with liquid-liquid extraction and nitrogen phosphorus detection (GC/NPD) was developed and validated for the determination of topiramate (TPM) in human body fluids. The galactopyranose analog of TPM was used as the internal standard. Capillary gas chromatographic conditions yielded typical retention times of 6.8 min for TPM and 7.2 min for the internal standard. Calibrations were linear between 1.0 and 32 microg/mL. Between-day precision (n = 17) for three serum controls (3.0, 10, and 24.5 microg/mL) resulted in coefficients of variation of 6.9%, 7.3%, and 4.9%, respectively. The limit of detection was 0.42 microg/mL. There was an excellent linear correlation between the fluorescence-polarization immunoassay (FPIA) and GC/NPD determinations of 56 patient specimens (r2 = 0.981). Chromatograms showed no interfering peaks with the respective blank human samples or from many commonly prescribed drugs. Because of improved specificity and decreased sample volume requirements, this micromethod should be particularly useful for monitoring TPM therapy in pediatric patients, for patients with impaired renal function, and for research studies.

Comparison of time-dependent effects of (+)-methamphetamine or forced swim on monoamines, corticosterone, glucose, creatine, and creatinine in rats

BackgroundMethamphetamine (MA) use is a worldwide problem. Abusers can have cognitive deficits, monoamine reductions, and altered magnetic resonance spectroscopy findings. Animal models have been used to investigate some of these effects, however many of these experiments have not examined the impact of MA on the stress response. For example, numerous studies have demonstrated (+)-MA-induced neurotoxicity and monoamine reductions, however the effects of MA on other markers that may play a role in neurotoxicity or cell energetics such as glucose, corticosterone, and/or creatine have received less attention. In this experiment, the effects of a neurotoxic regimen of (+)-MA (4 doses at 2 h intervals) on brain monoamines, neostriatal GFAP, plasma corticosterone, creatinine, and glucose, and brain and muscle creatine were evaluated 1, 7, 24, and 72 h after the first dose. In order to compare MAs effects with stress, animals were subjected to a forced swim test in a temporal pattern similar to MA administration [i.e., (30 min/session) 4 times at 2 h intervals].ResultsMA increased corticosterone from 1–72 h with a peak 1 h after the first treatment, whereas glucose was only increased 1 h post-treatment. Neostriatal and hippocampal monoamines were decreased at 7, 24, and 72 h, with a concurrent increase in GFAP at 72 h. There was no effect of MA on regional brain creatine, however plasma creatinine was increased during the first 24 h and decreased by 72 h. As with MA treatment, forced swim increased corticosterone more than MA initially. Unlike MA, forced swim reduced creatine in the cerebellum with no change in other brain regions while plasma creatinine was decreased at 1 and 7 h. Glucose in plasma was decreased at 7 h.ConclusionBoth MA and forced swim increase demand on energy substrates but in different ways, and MA has persistent effects on corticosterone that are not attributable to stress alone.

Topiramate concentration in saliva: an alternative to serum monitoring.

This study examines the relationship between serum and saliva topiramate concentrations, and attempts to determine if saliva may be a useful alternative to serum for therapeutic monitoring. Saliva and blood specimens were collected from 31 epilepsy patients (mean age 10.5 +/- 6.0 years; range 2.5 years to 24.8 years), and topiramate concentrations were determined by fluorescence polarization immunoassay. One patients results were omitted because the saliva concentration was below the limit of quantitation of the assay. A strong correlation exists between serum and saliva topiramate concentrations (adjusted r(2) = 0.97, n = 30, P < 0.0001). The mean fraction of saliva to serum concentration is 89.8% +/- 12.1% (range 62.9% to 112.7%). The results of this study support the use of saliva as a viable alternative to serum for monitoring topiramate therapy. Topiramate concentration in saliva: an alternative to serum monitoring.

Stability of salivary concentrations of the newer antiepileptic drugs in the postal system.

Saliva antiepileptic drug (AED) concentrations strongly correlate with serum concentrations. Saliva collection is painless and noninvasive, and untrained personnel can easily be taught the collection process. Remote patients could mail saliva samples to a laboratory for monitoring, and samples could be obtained in the immediate postictal state to provide a “real-time” concentration. The objectives of this study were to assess the stability of saliva lamotrigine (LMT), levetiracetam (LEV), oxcarbazepine (OXC), topiramate (TPM), and zonsiamide (ZNS) concentrations sent through the United States Postal Service (USPS) and to quantify the amount of time needed for patients and the USPS to return samples to clinic. Saliva samples were obtained from patients currently taking 1 of the targeted AEDs. Samples were split into 2 storage vials. One sample was sealed in an addressed envelope, which the patient mailed from home, whereas the other sample was frozen immediately. Postmark date and day returned were collected for mailed samples. Saliva concentrations were determined using HPLC. Wilcoxon rank sum tests were used to compare the immediately-frozen and mailed sample means. Correlations were determined by the Spearman test. Thirty-seven patients were enrolled in the study. The median time between collection and postmark was 1 day (range 0-6 days); and between collection and receipt was 4 days (range 1-160 days). The mean concentrations for mailed and immediately frozen samples were similar for each AED (P > 0.15). Spearman rank order correlations between mailed and immediately frozen aliquots were strong (LMT rs = 1, LEV rs = 1, OXC rs = 0.964, TPM rs = 0.90, and ZNS rs = 1). Saliva samples mailed by patients maintain stability and can be returned in a reasonable length of time. Further studies are needed to assess patient/caretaker capability of obtaining an adequate sample.

Feasibility and limitations of oxcarbazepine monitoring using salivary monohydroxycarbamazepine (MHD).

The purpose of this study is to determine the feasibility of using 10-hydroxy-10,11-dihydrocarbazepine (MHD) concentration in saliva as an alternative to serum for the therapeutic monitoring of oxcarbazepine (OXC) treatment. Investigators identified subjects seen in neurology clinics at the University of Kentucky Chandler Medical Center. Patients were eligible if they agreed to participate in this study, were taking oxcarbazepine, and if a serum MHD concentration had been ordered by their physician. Unstimulated saliva specimens (0.25 mL minimum) were collected in the clinic and frozen until analysis. Blood samples were obtained by phlebotomy. Serum specimens were analyzed by a reference laboratory. Saliva MHD concentrations were determined by high-performance liquid chromatography in the Clinical Laboratory at the Cincinnati Childrens Hospital Medical Center. Linear regression analysis was used to evaluate correlations. Saliva and blood specimens were collected from 28 epilepsy patients, but usable samples were obtained from only 23. The mean serum MHD concentration was 23.9 ± 10.0 μg/mL, and the mean saliva concentration was 23.1 ± 10.1 μg/mL. There was a significant positive correlation between the serum and saliva concentrations: saliva (y) = 0.95 serum (x) + 0.39; r = 0.941; n = 23; P < 0.001). The mean saliva:serum MHD concentration ratio was 0.96 ± 0.15. The results of the current study indicate that the relationship between freely flowing (unstimulated) saliva and serum concentrations of MHD is sufficient for therapeutic drug monitoring. A limitation of saliva MHD monitoring is that individuals who have difficulty producing small quantities of saliva or who have viscous saliva should generally be avoided for this type of monitoring. It is also recommended to avoid saliva collection within 8 hours after OXC dosing to allow complete absorption and transformation of the parent drug.

Correlation of Lamotrigine Concentrations between Serum and Saliva

Study Objective. To compare the relationship between serum and salivary concentrations of lamotrigine in pediatric and adult epilepsy populations.