Bum-Chae Choi

Di(2-ethylhexyl)phthalate leached from medical PVC devices serves as a substrate and inhibitor for the P-glycoprotein.

A di(2-ethylhexyl)phthalate (DEHP) was accidentally extracted from plastics in the process of purification of chemosensitizers reversing P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). The purpose of this study was to investigate the Pgp-reversal activities of phthalates, which are endocrine-disrupting chemicals, by utilizing the Pgp-overexpressing leukemic cell line AML-2/D100. The phthalates includes DEHP, diethyl phthalate (DEP) and dibutyl phthalate (DBP). Of the tested phthalates, DEHP showed the highest Pgp-reversal activity and DEP the most potent drug-accumulating activity. On the other hand, they did not show any chemosensitizing activity against multidrug resistance associated protein-mediated MDR. The complete inhibition of Pgp by verapamil increased the cytotoxicity of DEHP, but neither DEP nor DBP had this effect, suggesting that DEHP alone may be a possible substrate for the Pgp. DEHP showed higher hydrophobicity than the other phthalates when determined by reverse phase-HPLC. In addition, DEHP, but not the others increased the ATPase activity in a concentration-dependent manner. This is the first report that phthalates can reverse Pgp-mediated MDR by increasing drug accumulation, as well as serving as substrates for the Pgp. It is thought that the hydrophobic characteristics of phthalates could play an important role in Pgp-inhibitory activity. Therefore, pharmaco- and toxicokinetic interactions between phthalates leached from medical PVC devices and substrates for the Pgp should be kept in mind.

Association study of +45G15G(T/G) and +276(G/T) polymorphisms in the adiponectin gene in patients with polycystic ovary syndrome

The polycystic ovary syndrome (PCOS) is considered as one of the most common endocrine and reproductive dysfunctional diseases. Recent research for genetic variants has identified genetic influences between the polymorphisms of the adiponectin gene and the metabolic syndromes. The aim of our study was to investigate the relationship between single nucleotide polymorphisms (SNPs) in the adiponectin gene and PCOS. Two SNPs, +45G15G(T/G) and +276(G/T), which are found in exon 2 and intron 2, respectively, of the adiponectin gene, were genotyped by PCR-RFLP. Out of 303 women studied for the +45G15G(T/G) and +276(G/T) SNPs, 144 had PCOS and 159 were healthy controls. No association was found between the +45(T/G) SNP and PCOS (P=0.3558, OR=0.83, 95% confidence interval), per contra to the association between +276(G/T) SNP and PCOS (P=0.0126, OR=0.60, 95% confidence interval). These results indicate that the SNP of +276(G/T) is strongly associated with PCOS. However, the +45(T/G) SNP is not associated with PCOS.

Association between INS-VNTR polymorphism and polycystic ovary syndrome in a Korean population.

Polycystic ovary syndrome (PCOS) is a common disorder in women of reproductive ages. But its etiology is not fully understood yet. Variability in the number of tandem repeats of the insulin gene (INS-VNTR) is known to associate with PCOS, and it is associated with an increased risk of diabetes mellitus and other cardiovascular diseases. The aim of our study was to analyze an association between the INS-VNTR polymorphism and PCOS in a Korean population. The −23/Hph I polymorphism was used as a surrogate marker for INS-VNTR polymorphism and a total of 218 PCOS patient and 141 control DNAs were analyzed by restriction fragment length polymorphism method. Statistical analysis of genotyping results were performed using HapAnalyzer. χ2 test and logistic regression were used to analyze the association between two groups. A p value <0.05 was considered statistically significant. The frequencies of A/A and A/T genotypes indicated a similar change between PCOS patients and controls. In conclusion, there was no association between PCOS and INS-VNTR polymorphism (p = 0.0544, odds ratio = 1.69). Our present data demonstrate that INS-VNTR polymorphism is not related with PCOS in Korean women. Thus, it is suggested that INS-VNTR polymorphism is not a key factor in the etiology and the pathogenesis of PCOS in a Korean population.

Relationship between leptin receptor and polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, which is involved in the multi-system disease, and its etiology is still not clearly understood. It is currently considered that not only the genetic factors but also the environment factors play a crucial role in the pathogenesis of PCOS. Obesity plays an important role through the insulin, leptin and endocannabinoid system in the pathological process of PCOS, leading to more severe clinical manifestations. The aim of our present study is to investigate whether there is association between single nucleotide polymorphisms (SNPs) of Gln223Arg and Pro1019Pro in the leptin receptor gene (LEPR) and PCOS in a Korean population. Interestingly, a significant association was found between the Pro1019Pro in LEPR gene and PCOS, and a highly significant association was found between the Gln223Arg in LEPR gene and PCOS (P=0.033, OR=1.523, 95% confidence interval and P<0.0001, OR=0.446, 95% confidence interval). Moreover, genotype combination and haplotype analyses indicate that Gln223Arg and Pro1019Pro polymorphisms of LEPR are significantly associated with the risk of PCOS.

Genetic variation in the Mcp-1 gene promoter associated with the risk of polycystic ovary syndrome.

Monocyte chemoattractant protein-1 (MCP-1) is a pivotal chemokine in the inflammatory response, which plays an important role in recruiting monocytes to sites of injury and infection. However, the exact mechanism of Mcp-1 associated with PCOS risk was unknown. In this study, we explored whether the Mcp-1 -2518G>A polymorphism increases the risk of PCOS. We performed a comparative study of -2518G>A polymorphism of the Mcp-1 gene with PCOS. In addition, luciferase reporter assay was performed to evaluate the Mcp-1 transcriptional activity. A strong association was observed between the -2518G>A polymorphism of Mcp-1 gene and PCOS (p-value = 0.016, odd ratio (OR) = 0.693). A p-value under 0.05 is considered statistically significant. The genotype and allelic frequencies were assumed to be in Hardy-Weinberg equilibrium (HWE). The luciferase assays in 2 cell lines showed that the Mcp-1 -2518G>A substitution can increase the expression of Mcp-1. MCP-1 levels in serum for PCOS group were significantly higher than those in serum for controls (p-value = 0.02). Furthermore, the patients carrying a genotype A/A had significantly increased levels of MCP-1 in serum compared with levels of the MCP-1 of the patients with genotypes G/G and G/A (p-value = 0.031). This is the first study on the genetic variation of the Mcp-1 gene and PCOS. This finding suggests that the Mcp-1 -2518G>A polymorphism is associated with PCOS risk by affecting transcriptional activity, leading to an increased expression level of Mcp-1.

Opposing roles of inter-α-trypsin inhibitor heavy chain 4 in recurrent pregnancy loss

Background The mechanism behind an increased risk of recurrent pregnancy loss (RPL) remains largely unknown. In our previous study, we identified that inter-α-trypsin inhibitor heavy chain 4 (ITI-H4) is highly expressed at a modified molecular weight of 36 kDa in serum derived from RPL patients. Yet, the precise molecular mechanism and pathways by which the short form of ITI-H4 carries out its function remain obscure. Methods Human sera and peripheral blood mononucleated cells (PBMCs) were collected from patients and normal controls to compare the expression levels of ITI-H4 and plasma kallikrein (KLKB1). Flow cytometric assay was performed to measure inflammatory markers in sera and culture supernatants. Furthermore, to investigate the functions of the two isoforms of ITI-H4, we performed migration, invasion, and proliferation assays. Findings In the current study, we showed that ITI-H4 as a biomarker of RPL could be regulated by KLKB1 through the IL-6 signaling cascade, indicating a novel regulatory system for inflammation in RPL. In addition, our study indicates that the two isoforms of ITI-H4 possess opposing functions on immune response, trophoblast invasion, and monocytes migration or proliferation. Interpretation The ITI-H4 (∆N688) might be a crucial inflammatory factor which contributes to the pathogenesis of RPL. Moreover, it is expected that this study would give some insights into potential functional mechanisms underlying RPL. Fund This study was supported by the Ministry of Health & Welfare of the Republic of Korea (HI18C0378) through the Korea Health Industry Development Institute.

54G/C polymorphism of SREBF-1 gene is associated with polycystic ovary syndrome.

OBJECTIVE A sterol regulatory element-binding protein (SREBF-1) transcription factor is a major regulator of lipid metabolism, carbohydrate, and plays a key role in energy homeostasis. The 54(G/C) polymorphism of SREBF-1 gene was reported that it is related with metabolic diseases including obesity, type 2 diabetes, and dyslipidemia. Among these, polycystic ovary syndrome (PCOS) is known as a common metabolic-endocrine disorder of women in reproductive ages. STUDY DESIGN Here, we performed a comparative study of 54(G/C) polymorphism of SREBF-1 gene with PCOS. The 54(G/C) polymorphism of SREBF-1 gene was analyzed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) of total 286 PCOS patients and 149 matched controls of healthy women. Statistical analysis was performed using HapAnalyzer. A p-value under 0.05 was considered statistically significant. RESULTS There was a strong association between the 54(G/C) polymorphism of SREBF-1 gene and PCOS (OR: 0.65, 95% CI: 0.46-0.90, p: 0.0129). The genotype and allelic frequencies were in Hardy-Weinberg equilibrium (HWE). CONCLUSION This is the first study on the genetic variation of SREBF-1 gene and PCOS. We concluded that 54(G/C) polymorphism of SREBF-1 gene is associated with PCOS. Therefore, our results suggest that SREBF-1 gene may play a role in genetic predisposition to PCOS, which is helpful in understanding the etiology of PCOS.