Hyung-Ki Kim

Pharmacokinetics of ginsenoside Rb1 and its metabolite compound K after oral administration of Korean Red Ginseng extract

Compound K is a major metabolite of ginsenoside Rb1, which has various pharmacological activities in vivo and in vitro. However, previous studies have focused on the pharmacokinetics of a single metabolite or the parent compound and have not described the pharmacokinetics of both compounds in humans. To investigate the pharmacokinetics of ginsenoside Rb1 and compound K, we performed an open-label, single-oral dose pharmacokinetic study using Korean Red Ginseng extract. We enrolled 10 healthy Korean male volunteers in this study. Serial blood samples were collected during 36 h after Korean Red Ginseng extract administration to determine plasma concentrations of ginsenoside Rb1 and compound K. The mean maximum plasma concentration of compound K was 8.35±3.19 ng/mL, which was significantly higher than that of ginsenoside Rb1 (3.94±1.97 ng/mL). The half-life of compound K was 7 times shorter than that of ginsenoside Rb1. These results suggest that the pharmacokinetics, especially absorption, of compound K are not influenced by the pharmacokinetics of its parent compound, except the time to reach the maximum plasma concentration The delayed absorption of compound K support the evidence that the intestinal microflora play an important role in the transformation of ginsenoside Rb1 to compound K.

Changes in Dpysl2 expression are associated with prenatally stressed rat offspring and susceptibility to schizophrenia in humans.

Exposure to stress during critical periods of fetal brain development is an environmental risk factor for the development of schizophrenia in adult offspring. In the present study, a repeated-variable stress paradigm was applied to pregnant rats during the last week of gestation, which is analogous to the second trimester of brain development in humans. Behavioral and proteomic analyses were conducted in prenatally-stressed (PNS) adult offspring and non-stressed (NS) adult controls. In the behavioral tests, grooming behavior in the social interaction test, line-crossing behavior in the open field test, and swimming behavior in the forced swimming test were decreased in the PNS group. Western blot analysis and immunohistochemical analysis revealed that the expression of dihydropyrimidinase-like 2 (Dpysl2) or collapsin response mediator protein 2 (Crmp2) was downregulated in the prefrontal cortex and hippocampus of rats in the PNS group. Subsequently, single-nucleotide polymorphisms (SNPs) of the human dihydropyrimidinase-like 2 (DPYSL2) gene were analyzed in a population. Two functional SNPs (rs9886448 in the promoter region and rs2289593 in the exon region) were associated with susceptibility to schizophrenia. The present findings demonstrated that the downregulation of genes such as Dpysl2 and Dypsl3 in a rat model of prenatal stress may affect subsequent behavioral changes and that polymorphisms of the DPYSL2 gene in humans may be associated with the development of schizophrenia. Taken together with previous studies investigating the association between the DPYSL2 gene and schizophrenia, the present findings may contribute additional evidence regarding developmental theories of the pathophysiology of schizophrenia.

Influence of Panax ginseng on the offspring of adult rats exposed to prenatal stress

The exposure of pregnant females to stress during a critical period of fetal brain development is an environmental risk factor for the development of schizophrenia in adult offspring. Schizophrenia is a group of common mental disorders of unclear origin, affecting approximately 1% of the global population, showing a generally young age at onset. In the present study, a repeated variable stress paradigm was applied to pregnant rats during the final week of gestation. The effects of an extract of Panax ginseng C.A. Meyer (PG) on rats exposed to prenatal stress (PNS) were investigated in terms of behavioral activity and protein expression analyses. In the behavioral tests, grooming behavior in a social interaction test, line-crossing behavior in an open-field test and swimming activity in a forced-swim test were decreased in the rats exposed to PNS compared with the non-stressed offspring; the changes in behavioral activity were reversed upon oral treatment with PG (300 mg/kg). Subsequently, western blot analysis and immunohistochemical analyses of the prefrontal cortex and hippocampus revealed that the downregulation of several neurodevelopmental genes which occurred following exposure to PNS was reversed upon treatment with PG. The current findings demonstrate that the downregulation of several genes following exposure to PNS may affect subsequent behavioral changes, and that these phenomena are reversed following treatment with PG during pregnancy. Our results suggest that oral treatment with PG reduces the incidence of psychiatric disorders, such as schizophrenia.

A polymorphism in DMT1 is associated with lead-related hypertensive status

Divalent metal transporter 1 (DMT1) is an iron transporting membrane protein important for dietary iron uptake and as a carrier of other metals, such as zinc, copper, and lead. This study evaluated the possible association of DMT1 with clinical variables in a lead-exposed population. We investigated three single nucleotide polymorphisms (SNPs) (1303C/A, 1254T/C and IVS4+44C/A) of DMT1 in 662 male lead-exposed workers from Korea using polymerase chain reaction-restriction fragment length polymorphism. Among the three SNPs, the frequencies of IVS4+44C/A were significantly different between normotensive and hypertensive subjects. This suggests that a polymorphism in DMT1 is associated with increased risk of lead-related hypertensive status in a Korean male population.

Genetic relationship between an endothelin 1 gene polymorphism and lead-related high blood pressure

This study investigated the effect of an endothelin 1 (EDN1) T-1370G polymorphism on blood lead levels and lead-related blood pressure (LBP) of male Korean workers who had exposure to lead. A cross sectional study involving 771 male lead-exposed workers from Korea was conducted. High resolution melting analysis was used to differentiate the genotypes of the polymorphism. Association of clinical characteristics with genotypes as modifiers was estimated after adjusting for age, smoking status, drinking status, and job duration. Genotype and allele frequencies of the polymorphism were found to be associated with LBP. Blood lead levels were not associated with genotype or allele frequencies. Based on these results, it was concluded that G allele carrier (GG or GG+TG) and G allele of EDN1 polymorphism might be a risk factor of lead-related high blood pressure.

A polymorphism in AGT and AGTR1 gene is associated with lead-related high blood pressure

We investigated the association of polymorphisms in two renin-angiotensin system-related genes, expressed as angiotensinogen (AGT) and angiotensin II type 1 receptor (AGTR1), with blood lead levels and lead-related blood pressure in lead-exposed male workers in Korea. A cross-sectional study involving 808 lead-exposed male workers in Korea was conducted using a restriction fragment length polymorphism-based strategy to differentiate the various genotypes of polymorphisms in the AGT and AGTR1 genes. The association of clinical characteristics with genotypes as modifiers was estimated after adjustment for age, smoking status, drinking status, body mass index and job duration of each subject. Genotype and allele frequencies of the M235T polymorphism in AGT were associated with lead-related high blood pressure status. Moreover, blood lead levels were associated with allele frequencies of the AGT M235T polymorphism. These results suggested that the M/M genotype and M allele of AGT are risk factors for lead-related high blood pressure.

Effects of tianeptine on symptoms of fibromyalgia via BDNF signaling in a fibromyalgia animal model

Previous reports have suggested that physical and psychological stresses may trigger fibromyalgia (FM). Stress is an important risk factor in the development of depression and memory impairments. Antidepressants have been used to prevent stress-induced abnormal pain sensation. Among various antidepressants, tianeptine has been reported to be able to prevent neurodegeneration due to chronic stress and reverse decreases in hippocampal volume. To assess the possible effect of tianeptine on FM symptoms, we constructed a FM animal model induced by restraint stress with intermittent cold stress. All mice underwent nociceptive assays using electronic von Frey anesthesiometer and Hargreaves equipment. To assess the relationship between tianeptine and expression levels of brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and phosphorylated cAMP response element-binding protein (p-CREB), western blotting and immunohistochemistry analyses were performed. In behavioral analysis, nociception tests showed that pain threshold was significantly decreased in the FM group compared to that in the control group. Western blot and immunohistochemical analyses of medial prefrontal cortex (mPFC) and hippocampus showed downregulation of BDNF and p-CREB proteins in the FM group compared to the control group. However, tianeptine recovered these changes in behavioral tests and protein level. Therefore, this FM animal model might be useful for investigating mechanisms linking BDNF-CREB pathway and pain. Our results suggest that tianeptine might potentially have therapeutic efficacy for FM.

Effects of Tianeptine on Adult Rats Following Prenatal Stress

Objective Exposing a pregnant female to stress during the critical period of embryonic fetal brain development increases the risk of psychiatric disorders in the offspring. The objective of this study was to investigate the effect of antidepressant tianeptine on prenatally stressed (PNS) rats. Methods In this study, a repeated variable stress paradigm was applied to pregnant rats during the last week of gestation. To investigate the effects of antidepressant tianeptine on PNS rats, behavioral and protein expression analyses were performed. Forced swim test, open field test, and social interaction test were performed to determine changes in PNS rats compared to non-stressed offspring. Haloperidol was used as a positive control as an antipsychotic drug based on previous studies. Results Behavioral changes were restored after treatment with tianeptine or haloperidol. Western blot and immunohistochemical analyses of the prefrontal cortex revealed downregulation of several neurodevelopmental proteins in PNS rats. After treatment with tianeptine or haloperidol, their expression levels were increased. Conclusion Downregulation of several proteins in PNS rats might have caused subsequent behavioral changes in PNS rats. After tianeptine or haloperidol treatment, behavioral changes in PNS rats were restored. Therefore, tianeptine might decrease incidence of prenatal stress related-psychiatric disorders such as depression and schizophrenia.

SAT0010 Common epitope structure of HLA-DPB1 in systemic sclerosis

Background Specific alleles of HLA-DPB1 (HLA-DPB1*0901, *1301, *0301) were found to be most strongly associated with anti-topoisomerase I (Topo-I)-positive systemic sclerosis (SSc) in multiethnic genome-wide association study and HLA-analysis (1, 2). However, structural basis on which HLA-DPB1 alleles can bind Topo-I peptides is unknown. Objectives To find common characteristics of amino acid sequences in the risk HLA-DPB1 alleles and to reveal the possible mode of binding with Topo-I. Methods We enrolled 127 Korean patients with SSc who were diagnosed as SSc according to the preliminary classification criteria of American College of Rheumatology and 548 healthy Korean controls. We compared amino acid sequences of the risk HLA-DPB1 alleles with non-risk alleles, focusing on known HLA-DP binding motifs. After revealing common peptides from risk alleles of HLA-DPB1, molecular dynamic simulation was conducted to show binding structures against hypothetically chosen sequences of amino acids in Topo-I. Results The triplet of negative charged amino acids in three critical sites were associated with SSc. At amino acid position 55-57, 67-69, and 82, 84-85 of HLA-DPB1, negatively charged amino acids were prevalent, which includes glutamine or lysine. The patients who have 3 negative charged triplets show OR of 5.99 (95% CI=2.17-16.6, p=1.8×10-4) for SSc and those who have 2 negative charged triplets show OR of 6.37 (95% CI=2.35-17.3, p=7.1×10-5) or 3.89 (95% CI=1.39-10.9, p=6.5×10-3), while those who do not have triplets have referent OR of 1.00. When peptides from Topo-I (peptide A (KDREHRHKEHKK) and peptide B (KLLKEYGFCIMD)) were selected to simulate interaction with “high risk” HLA-DP allele (HLA-DPB1*0901) and “low risk” allele (HLA-DPB1*040101), peptide A and B fit more closely into the binding cleft of HLA-DPB1*0901 than HLA-DPB1*040101. (Figure 1) Conclusions SSc-susceptible HLA-DPB1 alleles share negative charged amino acid triplets at critical positions in their peptide binding groove. References Zhou, X., et al., Arthritis Rheum, 2009. 60(12): p. 3807-14. Arnett, F.C., et al., Ann Rheum Dis, 2010. 69(5): p. 822-7. Disclosure of Interest None Declared