Nam-Keun Kim

Increased Expression and Localization of a Serine Protease Inhibitor, Protease Nexin-1 (PN-1), in the Ovary and Uterus During Implantation in Rat

Protease nexin-1 (PN-1) is a serine protease inhibitor (serpin) that inactivates several proteases, including thrombin, urokinase, plasminogen activators (PA), and plasmin. It also plays a role in regulating proteolytic activity generated by PA system. PN-1 is known to be involved in tissue remodeling, cellular invasiveness, matrix degradation, and tumor growth. However, the role of PN-1 in female reproductive tracts, such as the uterus, ovary, and oviduct, during pregnancy is not known. The present study was designed to investigate the changes of PN-1 mRNA level and localization in the tracts during implantation and early pregnancy by using reverse transcription (RT)-polymerase chain reaction (PCR) and in situ hybridization. We found that PN-1 mRNA levels were coordinately regulated during early pregnancy in a stage- and tissue-specific manner, such that an increased expression of PN-1 gene appeared at the time of the implantation period in the uterus and ovary. Both the uterus and ovary synthesized PN-1 mRNA and their maximal PN-1 expression occurred on Day 6.5 postcoitum (p.c.). On 13.5 days of pregnancy, PN-1 level was low in the uterus and ovary. On the other hand, PN-1 mRNA in the oviduct did not show after 6.5 days of pregnancy. It appears that PN-1 mRNA in the uterus and ovary was highly regulated during early pregnancy, which might have an important role in implantation of rat blastocysts. PN-1 was localized in endometrial stromal cells of the uterus and in granulosa cells of the unstimulated primary follicles in the ovary during periimplantation period. Also, PN-1 mRNA expression was higher at implantation period than that at nonimplantation period of pregnancy. In conclusion, PN-1 is expressed in female reproductive tracts and highly regulated during implantation and early pregnancy.

Limited clinical value of multiple blood markers in the diagnosis of ischemic stroke.

OBJECTIVES No ideal blood marker exists for the diagnosis of ischemic stroke. Combined use of multiple blood markers would enhance the ability of clinical diagnosis of ischemic stroke. DESIGN AND METHODS Blood concentrations of neuronal markers (NSE, VSNL-1, hFABP, and Ngb), astroglial markers (S100B and GFAP), inflammatory markers (IL-6 and TNF-α), blood-brain barrier marker (MMP-9), and hemostatic markers (PAI-1) were measured within 6-24 h of stroke onset. The area under the receiver operator characteristic (AUROC) curve of patients with ischemic stroke and stroke-mimic was compared after adding individual or a combination of blood markers to the clinical diagnostic assessment (age, atrial fibrillation, and Face-Arm-Speech Test [FAST]). RESULTS Despite acute elevations of blood IL-6, S100B, MMP-9, hFABP, and PAI-1 in univariate analysis, only IL-6, S100B, and MMP-9 were independently associated with ischemic stroke in multivariate analysis. The addition of biomarkers (IL-6, S100B, and MMP-9) did not improve the diagnostic performance of baseline clinical models with added biomarkers versus baseline clinical models alone (AUROC, 0.865 vs. 0.837, p=0.069). CONCLUSIONS IL-6, S100B, and MMP-9 markers are elevated in the peripheral blood during the acute phase of ischemic stroke. However, the clinical usefulness of these biomarkers is limited due to low discriminating ability when compared to clinical parameters alone in diagnosis of ischemic stroke.

Different Risk Factor Profiles between Silent Brain Infarction and Symptomatic Lacunar Infarction

Background/Aims: It is generally assumed that silent brain infarction (SBI) and symptomatic lacunar infarction (sLAC) share common vascular risk factors and their pathogeneses are known to be similar. However, few studies have conducted a risk factor profile analysis of the two diseases in a single study design. Methods: This study included 64 subjects with SBI lesions, 140 patients with sLAC, and 342 controls by retrospective investigation of brain MRI. Topographic findings and vascular risk factor profiles were compared. Results and Conclusion: Compared to the controls, the SBI group was found to be associated with hypertension (p = 0.002) and elevated plasma total homocysteine level (p = 0.02). The sLAC group was found to be associated with hypertension (p = 0.001), diabetes (p = 0.004), smoking (p = 0.002), ischemic heart disease (p = 0.01) and hyperlipidemia (p = 0.04). In the present study, risk factor profiles of the SBI and sLAC were not exactly the same, indicating a different pathogenesis between the two diseases.

The prevalence and risk factor analysis of silent brain infarction in patients with first-ever ischemic stroke☆

BACKGROUND To evaluate the prevalence and to identify the risk factors of silent brain infarction (SBI) in patients with ischemic stroke. METHODS A total of 395 consecutive patients with first-ever ischemic stroke that underwent brain MRI were enrolled in this study. The prevalences of vascular risk factors in a SBI-positive (n=132) and in a SBI-negative group (n=263) were compared. The prevalences and characteristics of SBI were further evaluated with respect to stroke subtype and periventricular white-matter hyperintensity (PWMH) lesion. RESULTS The frequency of SBI among the 395 study subjects was 33.4%, and 10.1% of the study subjects had multiple-SBI lesions. The most common lesion site was basal ganglia (47%). Multiple logistic regression analysis showed that hypertension (OR: 1.94, 95% CI: 1.22-3.07, P=0.005) and the presence of an advanced PWMH lesion (OR: 1.77, 95% CI: 1.06-2.96, P=0.030) were significantly associated with SBI. Furthermore, an advanced PWMH lesion (OR: 2.88, 95% CI: 1.19-6.95, P=0.010) was more associated with multiple-SBI lesions than with a single-SBI lesion. The frequency of SBI was higher among those with the small-vessel disease type (45.5%) than in those with the large-artery disease (32.5%) or cardioembolic stroke type (25.6%) (P=0.04). CONCLUSIONS The prevalence of SBI in patients with ischemic stroke was found to be high, and hypertension was found to be the most important risk factor of SBI. Small-vessel disease and a diffuse white-matter lesion were found to be closely associated with SBI, and especially with multiple-SBI lesions.

Different impact of hyperhomocysteinemia on cerebral small vessel ischemia and cervico-cerebral atherosclerosis in non-stroke individuals

BACKGROUND Our aim was to investigate the impact of plasma total homocysteine (tHcyt) levels on cervico-cerebral atherosclerosis and cerebral small vessel ischemia in non-stroke individuals. METHODS Demographic, laboratory, brain magnetic resonance imaging and magnetic resonance angiographic data were retrospectively analyzed in 682 non-stroke individuals. The association between plasma tHcyt and radiological indices of cervico-cerebral atherosclerosis (any presence of cervico-cerebral [aCC] atherosclerosis, extracranial [EC] atherosclerosis and intracranial [IC] atherosclerosis) and cerebral small vessel ischemia (silent brain infarct [SBI] and cerebral white matter hyperintensity [cWMH]) was analyzed after adjusting for cardiovascular risk factors. RESULTS There was no association between values for natural log-transformed tHcyt (log-Hcyt) and aCC atherosclerosis, EC atherosclerosis, or IC atherosclerosis. The log-Hcyt was independently associated with cWMH (OR: 3.07, 95% CI: 1.64-5.75) and SBI (OR: 2.91, 95% CI: 1.57-5.40) in multivariate analysis. Median plasma tHcyt level increased as the severity of cWMH increased. CONCLUSIONS Our results suggest that hyperhomocysteinemia plays a major role in the development of cerebral small vessel ischemia, but not in the development of atherosclerosis of major cerebral arteries.

Association between kinase insert domain-containing receptor gene polymorphism and haplotypes and ischemic stroke

BACKGROUND Kinase insert domain-containing receptor (KDR), a type 2 vascular endothelial growth factor receptor, plays a crucial role in angiogenesis and vascular integrity of blood vessels. We evaluated whether single nucleotide polymorphisms (SNPs) and haplotype of kinase insert domain-containing receptor (KDR) are associated with increased risk of ischemic stroke in the Korean population. METHODS Totals of 501 patients with ischemic stroke and 478 controls were screened for the KDR -604T>C, +1192G>A, and +1719A>T SNPs. Subgroup analysis was performed to determine whether the effect of KDR polymorphism is specific to certain etiological subtypes of ischemic stroke. In addition, haplotype frequencies of these three SNPs were analyzed in stroke patients and controls. RESULTS The SNP +1719T allele was associated with risk of ischemic stroke in a dose-dependent manner (TT vs. AA: adjusted OR: 1.90, 95% CIs: 1.29-2.81, p=0.001 and false discovery rate (FDR)=0.003). Subgroup analysis showed that the SNP +1719T allele had a slight but significant association with small vessel disease type (TT vs. AA: adjusted OR: 1.91, 95% CIs: 1.11-3.29, p=0.02). There was no association between SNP -604 and SNP +1192 and ischemic stroke risk. In haplotype analysis, the T-G-T (-604/+1192/+1719), T-A-T, and C-G-T haplotypes increased the relative risk of ischemic stroke. CONCLUSIONS The KDR +1719A>T polymorphism and its haplotypes are possible genetic determinants for the risk of ischemic stroke.

Association between kinase insert domain-containing receptor gene polymorphisms and silent brain infarction: A Korean study

BACKGROUND Kinase insert domain-containing receptor (KDR), vascular endothelial growth factor receptor-2, play a pivotal role in endothelial dysfunction, which may lead to silent brain infarction (SBI). We evaluated whether single nucleotide polymorphisms (SNPs) of KDR genes are associated with increased risk of SBI in a Korean population. METHODS A total of 383 patients with SBI and 387 controls were genotyped for the KDR -604T>C, 1192G>A, and 1719A>T SNPs. We separately analyzed this association according to the age (age≥65 and age<65) and the gender. We also compared haplotype frequencies between SBI patients and controls. RESULTS Genotype frequencies for three SNPs did not differ significantly between SBI patients and controls. In addition, haplotype analysis for three SNPs did not show a difference between patients and controls. However, the frequency of genotype of KDR -604T>C was significantly associated with an increased risk of SBI in the age<65 years old group (AOR=1.515, 95% CI, 1.003 to 2.289, p=0.048) and in male group (AOR=1.596, 95% CI, 1.018 to 2.503, p=0.042). CONCLUSIONS KDR -604T>C SNP may serve as genetic markers for the increased risk of SBI among the younger (<65 years) or male only Korean subpopulations.

Association between common genetic variants of α2A-, α2B-, and α2C-adrenergic receptors and ischemic stroke.

BACKGROUND The alpha2-adrenergic receptor (α2-AR) mediates physiological responses to endogenous catecholamine, and genetic variants of α2-AR may predispose to clinical vascular diseases. We evaluated whether common genetic variants of each three subtype of alpha2-adrenergic receptor (ADRA2A, ADRA2B, and ADRA2C) were associated with ischemic stroke. METHODS A total of 616 patients with ischemic stroke and 512 controls were genotyped for the ADRA2A 1780G>A, ADRA2B 301-303 I/D, and ADRA2C 322-325 I/D polymorphisms. Logistic regression analyses, adjusting for multiple comparisons, were used to determine the association between the minor allele of each of three ADRA2 genes and the risk of ischemic stroke and pathophysiological subtypes. RESULTS The ADRA2B 301-303 D allele was more prevalent in the stroke group, compared to controls (DD vs. II, OR: 1.78, 95% CI: 1.18-2.69; recessive, OR: 1.55, 95% CI: 1.06-2.26). A subgroup analysis revealed that this association was found only in the small vessel diseases (SVD) type (DD vs. II, OR: 1.92, 95% CI: 1.11-3.33). The ADRA2A and ADRA2C polymorphisms did not contribute to an increased risk of ischemic stroke or any pathophysiological subtype. CONCLUSIONS The ADRA2B 301-303 D allele confers an increased risk of overall ischemic stroke and SVD subtype.

Association of transforming growth factor-beta 1 gene polymorphism with genetic susceptibility to ossification of the posterior longitudinal ligament in Korean patients.

Ossification of the posterior longitudinal ligaments (OPLL) has been considered to be associated with abnormalities of bone metabolism, and transforming growth factor-β1 (TGF-β1) has been demonstrated to affect the bone remodeling process. We investigated two SNPs of the TGF-β1 promoter (-509C>T; rs1800469) and exon 1 (869T>C; rs1982073) in 298 Koreans (98 patients with OPLL and 200 control subjects). The promoter SNP -509C>T was determined by PCR and RFLP, and the TaqMan probe assay was used to determine 869T>C polymorphism genotypes. The subjects were divided into OPLL continuous group (continuous type plus mixed type) and OPLL segmental group (segmental and localized type). We also separately analyzed this association according to gender difference. There was no significant difference in genotype distributions of -509C>T and 869T>C polymorphisms of the TGF-β1 gene between OPLL patients and controls. A combined analysis of TGF-β1 -509C>T and 869T>C polymorphisms showed no significant association with OPLL, and a subgroup analysis did not show any significant correlation between the SNP -509C>T or SNP 869T>C and OPLL subgroups. Stratification by gender demonstrated no significant effect. We conclude that promoter region (-509C>T) and exon 1 (869T>C) polymorphisms are not associated with OPLL in the Korean population.

Association between VEGF and eNOS gene polymorphisms and lumbar disc degeneration in a young Korean population.

Disturbances in blood flow to intervertebral discs (IVD) play an important role in IVD degeneration. Vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) are extremely important angiogenic factors for vasodilation and neovascularization. We investigated the relationship between single nucleotide polymorphisms (SNPs) of the VEGF and eNOS genes and genetic susceptibility to lumbar IVD degeneration in a young adult Korean population. Two hundred and forty-one participants (aged 18 to 30 years), with or without low back pain, were selected for the study. Magnetic resonance imaging was made of the lumbar spine in all participants. The patient group (N = 102) had low back pain clinically and lumbar IVD degeneration radiographically. The control group (N = 139) included subjects with and without low back pain; all were negative radiographically for lumbar IVD degeneration. Using PCR-RFLP analysis, we analyzed VEGF (-2578C>A, -1154G>A, -634G>C, and 936C>T) and eNOS (-786T>C, 4a4b and 894G>T) SNPs. We made combined analyses of the genes and performed haplotype analyses. There were no significant differences in the genotype distribution of polymorphisms of VEGF and eNOS genes among patients and controls. However, the frequency of VEGF -2578CA +AA/-634CC combined genotypes was significantly higher in patients when compared with controls [odds ratio (OR) = 21.00; 95% confidence interval (CI) = 2.590- 170.240]. The frequencies of the -2578A/-1154A/-634C/936C (OR = 3.831; 95%CI = 1.068-13.742), -2578A/-1154A/-634C (OR = 3.356; 95%CI = 1.198-9.400), and -2578A/-634C/936C (OR = 10.820; 95%CI = 2.811-41.656) haplotypes were also significantly higher in patients than in controls. We conclude that the combined genotype VEGF -2578CA+AA/-634CC is a possible risk factor for IVD degeneration and the VEGF -2578A/-1154A/-634C/936C haplotype may increase the risk for development of IVD degeneration. Furthermore, the VEGF -634C allele appears to be associated with susceptibility to IVD degeneration.