Hye Duck Choi

Effects of Astaxanthin on Oxidative Stress in Overweight and Obese Adults

Oxidative stress is caused by an imbalance between the antioxidant and the reactive oxygen species, which results in damage to cells or tissues. Recent studies have reported that oxidative stress is involved in obesity, in addition to many other human diseases and aging. A prospective, randomized, double‐blind study was performed to investigate the effect of astaxanthin (ASX), which is known to be a potent antioxidant, on oxidative stress in overweight and obese adults in Korea. Twenty‐three adults with BMI > 25.0 kg/m2 enrolled in this study and were randomly assigned to two dose groups: ASX 5 mg and 20 mg once daily for 3 weeks. Malondialdehyde (MDA), isoprostane (ISP), superoxide dismutase (SOD) and total antioxidant capacity (TAC), as oxidative stress biomarkers, were measured at baseline and 1, 2 and 3 weeks after ASX administration. Compared with baseline, the MDA (by 34.6% and 35.2%) and ISP (by 64.9% and 64.7%) levels were significantly lowered, whereas SOD (by 193% and 194%) and TAC (by 121% and 125%) levels were significantly increased in two dose groups after the 3 week intervention. This study revealed that supplemental ASX for 3 weeks improved oxidative stress biomarkers by suppressing lipid peroxidation and stimulating the activity of the antioxidant defense system. Copyright

Pharmacokinetics and first-pass metabolism of astaxanthin in rats

Astaxanthin is a carotenoid with antioxidant, anti-cancer and anti-inflammatory properties. The pharmacokinetics of astaxanthin after its intravenous (5, 10, and 20 mg/kg) and oral (100 and 200 mg/kg) administration and its first-pass extraction ratios after its intravenous, intraportal or intragastric (20 mg/kg) administration were evaluated in rats. The pharmacokinetic parameters of astaxanthin were dose dependent after its intravenous administration, due to the saturable hepatic metabolism of astaxanthin, but dose independent after oral administration. The gastrointestinal absorption of astaxanthin followed the flip-flop model. The hepatic and gastrointestinal first-pass extraction ratios of astaxanthin were approximately 0·490 and 0·901, respectively. Astaxanthin was metabolised primarily by hepatic cytochrome P-450 1A1/2 in rats. Astaxanthin was unstable up to 4 h incubation in four rat gastric juices and up to 24 h incubation in various buffer solutions having a pH of 1-13. The tissue/plasma ratios of astaxanthin at 8 and 24 h after its oral administration (100 mg/kg) were greater than unity for all tissues studied, except in the heart, at 8 h, indicating that the rat tissues studied had high affinity for astaxanthin.

Protective Effects of Haematococcus Astaxanthin on Oxidative Stress in Healthy Smokers

Free radicals induced by cigarette smoking have been strongly linked to increased oxidative stress in vivo, contributing to the pathobiology of various diseases. This study was performed to investigate the effects of Haematococcus astaxanthin (ASX), which has been known to be a potent antioxidant, on oxidative stress in smokers. Thirty-nine heavy smokers (≥20 cigarettes/day) and 39 non-smokers were enrolled in this study. Smokers were randomly divided into three dosage groups to receive ASX at doses of 5, 20, or 40 mg (n=13, each) once daily for 3 weeks. Oxidative stress biomarkers such as malondialdehyde, isoprostane, superoxide dismutase, and total antioxidant capacity, and ASX levels in plasma were measured at baseline and after 1, 2, and 3 weeks of treatment. Compared with baseline, the plasma malondialdehyde and isoprostane levels decreased, whereas superoxide dismutase level and total antioxidant capacity increased in all ASX intervention groups over the 3-week period. In particular, isoprostane levels showed a significant dose-dependent decrease after ASX intake. The results suggest that ASX supplementation might prevent oxidative damage in smokers by suppressing lipid peroxidation and stimulating the activity of the antioxidant system in smokers.

Inhibitory effects of astaxanthin, β-cryptoxanthin, canthaxanthin, lutein, and zeaxanthin on cytochrome P450 enzyme activities.

Astaxanthin, β-cryptoxanthin, canthaxanthin, lutein and zeaxanthin, the major xanthophylls, are widely used in food, medicine, and health care products. To date, no studies regarding the inhibitory effects of these xanthophylls on the nine CYPs isozymes have been reported. This study investigated the reversible and time-dependent inhibitory potentials of five xanthophylls on CYPs activities in vitro. The reversible inhibition results showed that the five compounds had only a weak inhibitory effect on the nine CYPs. Lutein did not inhibit the nine CYPs activities. Astaxanthin weakly inhibited CYP2C19, with an IC₅₀ of 16.2 μM; and β-cryptoxanthin weakly inhibited CYP2C8, with an IC₅₀ of 13.8 μM. In addition, canthaxanthin weakly inhibited CYP2C19 and CYP3A4/5, with IC₅₀ values of 10.9 and 13.9 μM, respectively. Zeaxanthin weakly inhibited CYP3A4/5, with an IC₅₀ of 15.5 μM. However, these IC₅₀ values were markedly greater than the Cmax values reported in humans. No significant IC₅₀ shift was observed in the time-dependent inhibition screening. Based on these observations, it is unlikely that these five xanthophylls from the diet or nutritional supplements alter the pharmacokinetics of drugs metabolized by CYPs. These findings provide some useful information for the safe use of these five xanthophylls in clinical practice.

Effects of type 2 diabetes mellitus on the population pharmacokinetics of rifampin in tuberculosis patients

Diabetes mellitus (DM) is a well-known risk factor to develop tuberculosis (TB). Some reports indicate the serum concentrations of anti-TB drugs are lower in patients with TB and DM than those with TB only. Therefore, we developed a nonlinear mixed-effects model (NONMEM) to determine the population PK parameters of rifampin and assessed the effects of DM status in patients with TB. One-compartment linear modeling with first-order absorption was evaluated using the 206 plasma samples of rifampin from 54 patients with DM. Based on the final model, DM affected the absorption rate constant (ka) and the volume of distribution (Vd) of rifampin. The body mass index (BMI) of the patients affected rifampin clearance (CL). The ka of rifampin in patients with TB and DM was greater than that in patients with TB only. Further, the predicted Vd in patients with DM was greater than that in patients without DM. As Vd is inversely correlated with plasma concentrations, the rifampin concentrations were predicted to be lower in the patients with DM. The authors recommend administering the greater doses of rifampin for the treatment of TB in patients with DM compared with the doses for the patients without DM to prevent treatment failure.

Safety and efficacy of fibrate-statin combination therapy compared to fibrate monotherapy in patients with dyslipidemia: a meta-analysis.

BACKGROUND Dyslipidemia is a major risk factor for the development of cardiovascular disease. Treatment with fibrate, statins, or other lipid-lowering drugs prevents primary or recurrent cardiovascular events. However, all lipid-lowering drugs have side effects, which may become more severe if combination therapy is prescribed. METHODS We performed a meta-analysis of published data to compare the safety and efficacy of fibrates alone, compared to fibrate-statin combinations, in patients with dyslipidemia. Six articles were assessed in terms of the efficacy of therapy and nine from the viewpoint of therapeutic safety. RESULTS In terms of efficacy, fibrate-statin combinations afforded significantly greater reductions in the levels of total cholesterol (SE=-2.248; 95% CI 1.986-2.510), LDL cholesterol (SE=-2.274; 95% CI 2.015-2.533), and triglycerides (SE=-0.465; 95% CI 0.272-0.658) compared to fibrate alone. In terms of safety, treatment with fibrate alone was associated with a significant decrease in the number of kidney-related adverse events (RR=-0.547; 95% CI 0.368-0.812), compared to treatment with fibrate-statin combinations. CONCLUSION We suggest that treatment with a fibrate-statin combination affords clinical benefits that are superior to treatment with fibrate alone, but increases the risk of side effects (particularly renal). Therapy should thus be carefully monitored.

Effects of ACE and ADD1 gene polymorphisms on blood pressure response to hydrochlorothiazide: a meta-analysis.

Hydrochlorothiazide (HCTZ) is used to treat uncomplicated hypertension. However, many studies have reported the variance of inter-individual response to HCTZ. A meta-analysis of published data was conducted to evaluate the pharmacogenetic associations of ACE I/D and ADD1 Gly460Trp polymorphisms with blood pressure changes during HCTZ therapy. To analyze the influence of ACE I/D polymorphism, 4 studies including 1,439 patients were assessed and the 3 genotypes were compared (II vs. ID, II vs. DD, and ID vs. DD) with respect to blood pressure changes. A significant association between ACE and blood pressure change was observed for the comparison of the II and DD (standard differences in means = 0.256; 95% CI, 0.109 - 0.403). For ADD1 Gly460Trp polymorphism, 4 studies including 1,001 patients were assessed, and GlyGly vs. GlyTrp, GlyGly vs. TrpTrp and GlyTrp vs. TrpTrp genotype comparisons were analyzed. A significant association between ADD1 and blood pressure change was observed for the comparisons of GlyGly vs. GlyTrp (standard differences in means= 2.78; 95% CI, 0.563 - 4.99) and GlyGly vs. TrpTrp (standard differences in means = 1.80; 95% CI, 1.38 - 2.22). This study is the first meta-analysis to evaluate the influences of ACE and ADD1 polymorphisms on blood pressure responses to HCTZ to combine the inconsistent results of previous studies.

Cardiac toxicities of lapatinib in patients with breast cancer and other HER2-positive cancers: a meta-analysis

PurposeLapatinib is a tyrosine kinase inhibitor that targets the human epidermal growth factor receptor 2 (HER2) and the epidermal growth factor receptor (EGFR/HER1), and there are concerns about its cardiac toxicity. Recent studies of lapatinib have reported cardiac adverse events; however, the results have been inconsistent among the studies. The aim of our study was to estimate the cardiac toxicity of lapatinib in patients with breast cancer and other HER2-positive cancers.MethodsTo evaluate the cardiotoxicity of lapatinib, the results of previous studies were quantitatively integrated using meta-analysis. Forty-five articles regarding cardiac adverse events, including left ventricular dysfunction, left ventricular ejection fraction (LVEF) decrease, arrhythmia, and other cardiac adverse events, were assessed. As a subgroup analysis in patients with breast cancer, 26 studies of lapatinib-induced cardiac adverse events were assessed.ResultsThe overall incidence of cardiac adverse events was 2.70% (95% confidence interval [CI] 1.60–4.50%). The incidences of left ventricular dysfunction and LVEF decrease were 1.60% (95% CI 1.30–2.00%) and 2.20% (95% CI 1.30–3.60%), respectively. The overall incidence of cardiac adverse events was 3.00% (95% CI 1.50–6.10%) in patients with breast cancer, which was marginally higher than the rate in patients with all type of cancers.ConclusionThe overall incidence of lapatinib-induced cardiac toxicity was relatively low based on an indirect comparison with trastuzumab. However, careful monitoring of cardiac toxicity is still needed when patients are treated with lapatinib because the related risk factors have not been clearly identified.

Lack of association between DRD2 Taq1A gene polymorphism and smoking cessation therapy: a meta-analysis.

Recent studies have reported that genetic factors are significantly associated with smoking behavior, but the influence of the smoking behavior-related genes on smoking cessation treatment is still not clear. We analyzed the smoking cessation outcomes among previously reported studies involving participants who underwent smoking cessation therapy by comparing the following DRD2 Taq1A gene polymorphism using meta-analysis. In total, nine studies including 2,851 participants were assessed and the A1 allele carriers and A2 homozygotes were compared with respect to smoking cessation outcomes by meta-analysis. No significant association was observed for the main analysis (OR = 0.900; 95% CI, 0.751 - 1.078). In subgroup analysis, three studies were assessed by comparing participants with the A1/A1, A1/A2, and A2/A2 genotypes. A significant association between the DRD2 Taq1A polymorphism and< smoking cessation therapy was observed between the A1/A1 and A1/A2 genotypes (OR = 2.967; 95% CI 1.737 - 5.068) and between the A1/A2 and A2/A2 genotypes (OR = 0.547; 95% CI 0.392 - 0.762), but not between the A1/A1 and A2/A2 genotypes (OR = 1.269; 95% CI 0.746 - 2.157). This study is the first meta-analysis to evaluate and quantitatively integrate the association between the DRD2 Taq1A polymorphism and smoking cessation therapy. A significant relationship between DRD2 Taq1A polymorphism and smoking cessation therapy was not observed.

Pharmacokinetics of Clindamycin in the Plasma and Dialysate after Intraperitoneal Administration of Clindamycin Phosphoester to Patients on Continuous Ambulatory Peritoneal Dialysis: An Open-Label, Prospective, Single-Dose, Two-Institution Study

We evaluated the pharmacokinetics of clindamycin and the dose of clindamycin phosphate necessary to treat peritonitis after intraperitoneal administration of clindamycin phosphate to patients on continuous ambulatory peritoneal dialysis (CAPD). This was an open-label, prospective, single-dose study conducted at the two levels of institutional clinical care in South Korea. Twelve patients (six men and six women; all older than 25 years), mean CAPD duration of 38.2 months with various origins without peritonitis, received 600 mg clindamycin phosphate mixed with only the first 2-L dialysate (1.5% dextrose). The 1.5%, 1.5%, 2.5% and 1.5% dextrose dialysates were serially exchanged every 6 hr. If patients were non-anuric, 24-hr urine samples were also collected. Clindamycin phosphate was incompletely activated to clindamycin in the dialysate. The clindamycin concentration in the dialysate was greater than the effective concentration (5 μg/mL) at 6.87 μg/mL up to 6 hr. So, 600 mg clindamycin phosphate per every 6 hr dialysate is effective for treatment of peritonitis. It has been reported that the clindamycin concentrations in the dialysate may be higher in CAPD patients with peritonitis. Thus, we can expect that intraperitoneal administration of <600 mg clindamycin phosphate per every 6 hr dialysate could be maintained over 5 μg/mL in patients with peritonitis. The transfer of clindamycin was unidirectional from the dialysate to the plasma.