The role of the gut barrier function in the pathophysiology of viral liver cirrhosis.

BACKGROUND/AIMS: Plasma endotoxin levels commonly increase in patients with liver cirrhosis. We purposed to identify change of intestinal permeability and frequency of endotoxemia in patients with viral liver cirrhosis. Additionally, we studied the relationship between plasma endotoxin levels and failure of gut barrier function. METHODOLOGY: Subjects included 27 patients with viral liver cirrhosis (LC) and 45 volunteers as healthy control (HC). Intestinal permeability index was determined by the level of urinary excretion of polyethylene-glycol after oral administration and plasma endotoxin levels by using quantitative Limulus assay. Grades of liver dysfunction were categorized by Child-Pugh classification and MELD score. RESULTS: Intestinal permeability indexes were higher in LC than in HC (1.48±0.56%, n=27 vs. 0.93±0.50%, n=45, p=0.019). Plasma endotoxin levels were higher in LC than in HC (0.35±0.17EU/ mL vs. 0.11±0.14EU/mL, p<0.001). In LC, plasma endotoxin levels progressively increased in relation to severity of liver dysfunction (Child-Pugh class A (0.31±0.17EU/mL), B (0.37±0.14EU/mL) and C (0.42±0.23EU/mL), p=0.013, MELD category 1/2/3/4=0.27±0.14/0.39±0.17/0.32±0.21/0.47±0.28E U/mL, p=0.043). LC with/without portal hypertension (1.47±0.55%, p<0.01/1.29±0.59%, p<0.05) had higher intestinal permeability indexes than HC (0.93±0.50%). CONCLUSIONS: Severity of liver dysfunction was associated with endotoxemia. Although gut barrier function did not show a significant relationship with endotoxemia, increased intestinal permeability may be a significant finding that at least in part is associated with the pathophysiology of viral liver cirrhosis.

A Sexually Transmitted Disease (STD) DNA chip for the diagnosis of genitourinary infections.

The results of an investigation aimed at the development of a DNA chip for the detection of genitourinary infections are described. Through analysis of over 35,000 clinical cases, 14 pathogens which are most abundantly found among Koreans were selected and candidate sequences for capture probes were accordingly chosen by considering their sequences and ß-globin house-keeping gene. Among this group, the most suitable capture probe sequences were selected by employing repeated chip tests in which they are immobilized on a glass chip by using a recently developed novel gold nanoparticles-based method. A multiplex PCR method was established to generate fluorescence-labeled sequences for all 14 pathogens along with the ß-globin gene. By using optimized hybridization conditions, the final chip was constructed and employed to diagnose reliably both single and multiple infections in clinical human samples for 14 target pathogens. The results show that the novel chip methodology serves as a highly reliable and convenient tool for the diagnosis of Sexually Transmitted Diseases (STDs). Furthermore, this study has its great significance in that it demonstrates the entire process from statistical analysis of a large number of clinical cases to the final development of STD DNA chip just ready to be applied or commercialized in the clinical diagnostic field.

Application of allele-specific primer extension-based microarray for simultaneous multi-gene mutation screening in patients with non-syndromic hearing loss.

Congenital hearing loss (HL) is the most common sensory disorder in humans, affecting one in 1000 infants at birth. A high degree of genetic heterogeneity makes it difficult to screen for mutations in all known deafness genes in clinical applications. We have improved a genotyping microarray using the multiplex PCR-based allele-specific primer extension (ASPE) reaction and applied this method for the genetic diagnosis of congenital HL in Korea. Seven different mutations in the GJB2, SLC26A4 and mitochondrial 12S rRNA genes, which were identified on the basis of a previous study in a Korean population, were selected for the study. These genes were used to evaluate the accuracy of the microarray. The test for validation of the current version of HL genotyping microarray was fully concordant with the results of DNA sequencing in which 51 subjects with non-syndromic HL were originally genotyped. Furthermore, the blind test of the genotyping microarray detected four different mutations in 10 out of 65 patients, and the accuracy of microarray was calculated as 98% (64/65). Therefore, our results suggest that this HL genotyping microarray will be useful in clinical applications for the genetic diagnosis of HL.

Construction of a DNA chip for screening of genetic hearing loss.

OBJECTIVES: Hearing loss is the most common sensory disorder in humans and genetic causes are estimated to cause more than 50% of all incidents of congenital hearing loss. To develop an efficient method for a genetic diagnosis of hearing loss, we have developed and validated a genetic hearing loss DNA chip that allows the simultaneous analysis of 7 different mutations in the GJB2, SLC26A4, and the mtDNA 12S rRNA genes in Koreans. METHODS: A genotyping microarray, based on the allele-specific primer extension (ASPE) method, was used and preliminary validation was examined from the five patients and five controls that were already known their genotypes by DNA sequencing analysis. RESULTS: The cutoff Genotyping index (GI) of genotyping for each mutation was set up and validated to discriminate among the genotypes. The result of the DNA chip assay was identical to those of previous results. CONCLUSION: We successfully designed the genetic hearing loss DNA chip for the first time in Korea and it would be useful for a clinical genetic diagnosis of hearing loss. Further consideration will be needed in order to examine the accuracy of this DNA chip with much larger patient sample numbers.