소비재와 서비스 시장을 중심으로

학위논문(박사)--서울대학교 대학원 :생활과학대학 소비자학과,2019. 8. 여정성.시장의 경쟁은 자원의 효율적인 배분을 담보하는 필수적인 작동원리이다. 경제학에서는 완전경쟁시장에서 자원이 가장 효율적으로 배분되고 사회적 후생이 극대화된다고 보고 있으나, 현실에서 우리가 접하는 시장은 불완전 경쟁시장이 주를 이룬다. 문제는 이러한 시장에서 사업자와 직접 거래하는 주체인 소비자가 자유롭고 공정한 시장규범이 지켜지는 환경에서 소비자의 권리를 보장 받으면서 적정한 가격으로 재화와 서비스를 구입하고 충분한 소비자이익을 누리고 있는가 하는 점이다. 본 연구는 소비자의 실생활과 밀접한 소비재와 서비스의 시장집중도 수준과 그 수준별 분포를 살펴봄으로써 소비자들이 노출되어 있는 시장의 경쟁 정도를 검토하고, 이러한 시장집중도가 소비자후생에 미치는 영향을 규명하고자 하였다. 이를 위해 소비자물가지수 내 소비재와 서비스 품목을 연구대상으로 설정하고, 시장의 경쟁 정도를 대리하는 지표는 시장집중도(CR3, HHI)를 사용하였으며, 소비자후생은 경제적 이익을 포함하여 소비자의 권리, 심리적인 이익, 공정한 거래환경의 토대가 되는 법‧제도의 준수 여부 등을 포괄하는 광의의 개념으로 정의하여 이를 가격변동률, 소비자시장성과지수, 경쟁법 위반행위로 측정하였다. 본 연구는 첫째, 소비자물가지수 품목을 기준으로 소비재와 서비스 품목의 시장집중도 현황과 분포를 파악하였다. 둘째, 소비재와 서비스 산업의 시장집중도 수준별로 품목별 소비자물가지수 변동률에 차이가 존재하는지를 분석하였다. 셋째, 소비재와 서비스 산업의 시장집중도 수준별로 소비자시장성과지수에 차이가 존재하는지를 분석하였다. 넷째, 소비재와 서비스의 시장집중도 수준에 따라 경쟁법 위반행위의 정도와 내용에 차이가 존재하는지를 분석하였다. 본 연구는 일련의 분석을 통해 결과적으로 시장집중도의 수준이 소비자후생에 어떠한 영향을 미치는지를 종합적으로 고찰하고자 하였다. 이에 따라 본 연구에서 도출한 결과는 다음과 같다. 첫째, 소비자물가지수 품목을 대상으로 시장집중도를 분석한 결과 2015년 기준 소비재의 품목시장 집중도 CR3 단순평균과 품목가중치 기준 가중평균은 각각 65.1%와 66.5%, HHI는 2450과 2407 수준으로 나타났다. 또한 서비스의 산업집중도 CR3 단순평균과 가중평균은 각각 18.8%, 21.8%, HHI는 408, 621로 산출되었다. 2015년 소비재의 품목시장 집중도 분포는 CR3 40%이상 80%미만의 구간과 HHI 1,001～5,000인 구간에 각각 품목 수의 절반 이상이 집중되어 있었으며, 서비스 품목의 경우는 CR3 20%미만, HHI 500미만인 최저 구간에 60% 이상 집중적으로 분포하는 것으로 나타났다. 소비재의 경우 2015년 기준 CR3 75%이상인 시장지배적 사업자에 해당하는 품목 수는 39.6%로 높은 수준이었으며, 50%이상 75%미만인 품목도 32.4%로 나타나, 결국 품목시장 집중도가 50%이상인 소비재는 전체의 72%에 이르는 것으로 나타났다. 소비재의 경우 CR3 75%이상은 주요 가전용품, 자동차 및 관련 용품, 주류가 주로 분포하는 특성 보였다. 서비스의 경우에는 대부분의 산업이 CR3 50%미만에 집중되어 있었으며, 50%이상 75%미만에는 방송업과 각종 임대업이, 75%이상은 유‧무선통신업, 위성 및 기타 방송업, 영화관 운영업, 정기 항공 운송업이 포함되었다. 둘째, 소비재와 서비스 품목들의 시장집중도 수준에 따라 가격변동률에 차이가 존재하는지를 분석한 결과, CR3와 HHI 모두 전 집단의 지수변동률 평균이 양(+)의 값을 보여 전반적인 품목들의 가격은 상승한 것으로 나타났다. 또한 소비재의 경우 출하액 대비 영업비용 변동률을 통제한 상태에서도 품목별 지수변동률의 시장집중도 수준별 집단 간 차이가 매우 유의하였으며, 사후검정 결과 모두 중간 수준의 시장집중도 구간인 CR3 50%이상 75%미만과 HHI 1200이상 2500미만 집단이 각각 가장 높은 집중도 구간인 CR3 75%이상과 HHI 2500이상보다 지수변동률이 유의하게 높아 가격이 더욱 많이 상승한 것으로 나타났다. 서비스의 경우 통계적으로 유의하지는 않았으나 CR3 50%이상과 HHI 1200이상인 고집중도 집단이 각각 CR3 50%미만과 HHI 1200미만인 저집중도 집단보다 지수변동률 평균이 4.1%p, 6.3%p의 차이로 더 낮았다. 셋째, 33개 소비재 및 서비스 평가시장을 고집중 집단(CR3 50%이상 또는 HHI 1200이상)과 저집중 집단(CR3 50%미만이면서 HHI 1200미만)으로 구분하여 집중도 수준별 2015년과 2017년 소비자시장성과지수를 분석한 결과, 2015년은 CMPI(지수)와 5개 중 4개의 평가항목에서, 2017년은 KCMPI(지수)와 모든 평가항목에서 고집중 집단의 평균이 저집중 집단에 비해 높은 수준을 보였다. 다만 이러한 집단 간 차이는 2015년에 비해 2017년에 감소한 것으로 나타났는데, 이는 Mann-Whitney U test 결과 2015년에는 만족도와 신뢰성 평가항목에서 집중도 수준에 따른 집단 간 차이가 유의하였던 반면 2017년에는 지수 및 모든 평가항목에서 유의하지 않게 나타난 통계적 결과와도 일치하였다. KCMPI 산정 기준으로 두 해의 지수 및 평가항목 점수를 비교한 결과, 지수와 5개 중 3개의 평가항목에서 저집중 집단의 증가분이 고집중 집단에 비해 높게 나타났는데, 이는 저집중 시장의 소비자지향성 개선 정도가 고집중 시장에 비해 크다는 점을 시사한다. 또한 저집중 평가시장들은 두 해의 점수 차이가 대체적으로 비슷하거나 약간의 변화가 있는 수준인 반면 고집중 평가시장들은 평균보다 높았던 시장은 낮아지고, 낮았던 시장은 높아져 평가의 결과가 완전히 뒤바뀌는 시장이 적지 않게 관찰되는 특징을 보였다. 넷째, 소비재와 서비스의 시장집중도 수준별로 경쟁법 위반행위의 내용에 차이가 존재하는지를 보기 위해 연구대상 소비재 및 서비스 품목에서 2011∼2015년 기간 동안 경쟁법 위반행위가 발생하거나 지속된 사례 중 2011～2018년 기간 내에 심결이 이루어진 사건을 대상으로 행위의 내용과 그에 따른 소비자후생을 시장집중도 수준별로 분석한 결과, CR3가 50%미만인 저집중 품목에 비해 50%이상인 고집중 품목에서 보다 여러 유형의 경쟁법 위반행위가 발생하고 있는 것으로 나타났다. 특히 최고의 집중도 수준인 CR3 75%이상에서 경쟁제한적 기업결합 행위가 발생하였고, 재판매가격 유지행위와 부당공동행위 또한 대체적으로 50%이상 75%미만보다 75%이상 품목들에서 더욱 많이 발생한 것으로 분석되었다. CR3 50%미만의 저집중 품목의 경우 사업자단체 금지행위의 위반 건수가 두드러지게 많았고, 불공정거래행위는 모든 집중도 수준에서 가장 많이 발생하였으나 특히 저집중도 일부 품목에서 집중적으로 발생하였다. 다음의 결과에 대한 본 연구의 결론은 다음과 같다. 첫째, 소비재의 품목시장 집중도 단순평균이 65.1%에 이르고 CR3 75%이상인 비율이 40%에 육박하는바, 무엇보다 소비자의 실생활과 밀접한 소비재와 서비스의 상당수가 법적으로 시장지배적 사업자의 기준을 초과하는 시장집중도 수준에 이르고 있음을 소비자 스스로가 인지할 필요가 있다고 판단된다. 이는 소비자가 시장에서 발생하는 현상들을 시장구조의 맥락에서 보다 잘 이해하고, 필요 시 명확한 문제의식을 갖는 데 도움을 줄 수 있을 것이다. 또한 소비자로 하여금 시장 감시의 중요성을 환기하고 스스로 이에 보다 관심을 갖도록 동기를 부여할 수 있을 것이라 생각된다. 본 연구대상 소비재와 서비스는 소비자의 실생활과 밀접한 품목들로 시장의 경쟁 제한에 따른 폐해는 직접적으로 소비자후생과 직결되며 그 규모가 막대하다는 점에서 경쟁당국은 소비자의 지출 및 구입 빈도가 높은 품목 시장을 보다 면밀하게 모니터링할 필요성이 제기된다. 둘째, 시장집중도가 가장 높은 집단의 품목들이 평균적으로 가장 낮은 가격 상승 비율을 보임에 따라, 시장지배적 사업자가 보다 용이하게 가격을 큰 폭으로 인상시킬 수 있을 것이라는 통념은 지지되지 않았다. 고집중도 시장은 규모의 경제가 발생함에 따라 생산비용이 낮아져 가격 변동의 필요성이 상대적으로 크지 않을 가능성이 존재한다. 또한 경쟁제한성 측면에서 경쟁당국과 시장의 감시가 집중되며 맥주, 라면, 소주 등의 식품이나 휘발유, 경유 등의 에너지 관련 품목 등 소비자의 가격민감도가 높은 품목들을 포함하고 있어, 선행연구들이 지적하듯 시장의 이목이 집중되는 가격 변동 대신 신제품을 출시한다거나 원재료 가격의 증감 상황을 비대칭적으로 가격에 반영하는 등 우회적인 방법으로 가격 인상과 동일한 효과를 달성하고 있을 가능성도 존재한다. 기업들의 의도적인 가격 변동이라기보다는 자동차용품(내비게이션)이나 영상음향기기(마이크로컴포넌트)와 같은 시대적 수요의 변화, 시간의 변화와 기술의 발전에 따른 동일 사양 전자제품의 가격 하락, 휴대전화기나 교복과 같은 정책이나 사회적 여론에 민감한 재화의 존재 등 고집중 시장에 속하는 품목들의 특성도 낮은 가격 상승 비율에 영향을 미친 것으로 보인다. 결론적으로, 고집중도 시장의 가격 상승 비율은 다른 집중도 수준에 비해 높게 나타나지는 않았으나, 이를 소비자후생과 연관 지을 경우에는 가격 변동분만으로 설명되지 않는 다양한 측면을 보다 종합적으로 고려하여 판단해야 할 것으로 보인다. CR3 50%이상 75%미만과 HHI 1200이상 2500이상의 중간 집중도 집단은 평균 가격 상승 비율이 가장 높았고, 고집중도 집단보다 유의하게 가격의 상승 비율이 높았다는 점에서 소비자와 규제당국의 보다 면밀한 관심이 필요하다고 판단된다. 당해 시장들은 시장지배적 사업자의 요건에 미치지는 못하므로 경쟁제한성이 높은 시장이라 볼 수는 없을 것이나 집중도의 절대적인 수준만으로도 일정한 경쟁제한성을 띠고 있을 가능성이 높은 시장이라 보아야 함에도 실질적으로는 소비자와 규제당국의 모니터링 대상에는 벗어나 있어 상대적으로 가격을 변동시키기에 용이하였던 것으로 추측된다. 경쟁당국은 당해 집중도 시장이 가격변동성을 포함하여 시장에서 고집중도 시장과 저집중도 시장 중 어떠한 시장에 가까운 특성을 보이는지를 면밀히 주시할 필요성이 제기된다. 셋째, 소비자시장성과지수를 분석한 결과, 두 집단에 대한 지수 분석의 결과와 점수의 분포를 고려 시, 저집중 평가시장들은 2015년의 평가 결과가 각각 2017년의 결과에 상대적으로 큰 영향을 미치지 않은 것으로 보이며, 연별 점수의 평균적인 증가분 또한 상대적으로 크지 않았다. 이러한 결과는 저집중 시장이 소비자의 관심도나 사회적 이슈에 덜 민감하거나 혹은 이에 반응하여 즉각적인 성과를 내기에 상대적으로 불리한 시장구조를 가지고 있음을 시사하며, 그럼에도 저집중 시장은 거시적으로 고집중 시장에 비해 소비자지향성의 수준은 더욱 개선되고 있는 것으로 추정된다. 반면 고집중 평가시장들은 소비자의 높은 관심뿐 아니라 높은 시장집중도에 따른 시장감시의 대상으로서 시장에 대한 소비자의 태도나 평가에 보다 민감할 가능성이 높으며, 이에 2015년 평균보다 낮았던 지수의 수준이 2017년 급속하게 개선된 결과는 평가시장에 쏠린 사회적 이목을 의식한 시장의 반응으로 해석된다. 이렇듯 단기간 내에 집중적인 개선이 이루어질 수 있었던 것은 평가시장을 구성하는 사업자가 상대적으로 적어 서로의 기업행위에 영향을 주고받으면서 성과를 내기에 유리한 시장구조가 작용한 것으로 보인다. 2015년은 평균 이상의 소비자지향성 수준을 보인 반면 2017년은 평균보다 낮은 수준을 기록한 평가시장들도 존재하는데, 이는 소비자의 관심도가 높지 않을 시에는 고집중 시장이 소비자지향성을 개선하고자 하는 유인이 크지 않을 수 있음을 시사한다. 넷째, CR3 75%이상 고집중도 시장이 상대적으로 경쟁법 위반행위가 다양한 유형에서 높은 빈도로 이루어지고 있으므로 규제당국의 집중적인 모니터링이 보다 절실하게 요구된다. 특히 고집중도 시장은 저집중도 시장에 비해 시장과 소비자에 미치는 영향이 더욱 막대하다는 점에서도 중요성이 강조된다. CR3 50%이상 75%미만 시장은 고집중도 시장과 같이 어느 정도의 경쟁제한성을 전제하는 위반행위들이 발생하고 있어 당해 시장의 경쟁 정도와 시장 특성을 주시하여 규제의 공백이 발생하고 있지 않은지 점검이 필요하다. 마지막으로 CR3 50%미만 시장은 과도한 경쟁으로 인해 특정 품목에서 높은 건수의 불공정거래행위가 발생하고 있으므로, 경쟁이 과열된 시장에 대한 규제당국의 보다 단호하고 시의성 있는 정책적 개입이 필요하다고 판단되며, 각 지역의 개인 사업자들로 조직된 사업자단체가 당해 시장에서 소비자후생을 저해하는 영향력을 행사하는 일이 없도록 각 지역에 기반한 시장 모니터링의 역량이 강화되어야 할 것이다.Competition in the market is an essential operating principle that ensures efficient distribution of resources. The market that we come into contact with in reality, however, is mainly of an incomplete competing market. The questions is on whether in such market, the consumer who is the entity that deals directly with the business is guaranteed consumer rights in a free and fair market environment and whether they are ensured sufficient consumer interests. This study examines the concentration level and distribution of consumer goods and service market that is closely related to the everyday life of consumers to review the market competition in which consumers are exposed to, and the difference in Consumer Price Fluctuation, Korea Consumer Markets Performance Index, and Violations of the Competition Law per consumer goods and service market concentration level. Through this, it aimed at investigating the impact of market concentration on consumer benefits. The results of this study are as follows. First, upon analyzing market concentration for consumer price index items, it was found that in 2015, the simple average of the consumer goods market concentration rate and the weighted average based on weighted value were 65.1% and 66.5%, respectively, for CR3 and HHI were 2450 and 2407, respectively. For industry concentration rate of services, the simple average and weighted average were 18.8% and 21.8%, respectively, for CR3 and HHI were 408 and 621, respectively. The weighted average of consumer goods and service were generally higher than the simple average, and it was assumed that the market concentration of items with high expense rates were higher. The 2015 consumer goods market concentration rate distribution showed concentration accounting for more than half of each items in the CR40% to 80% and HHI 1,001-5,000 intervals, and the industry concentration rate of service items showed concentrated distribution in excess of 60% in the minimum intervals of CR3 20% and below and HHI 500 and below. As of 2015, the number of consumer material items corresponding to market-dominating businesses with over 75% CR3 was highest at 39.6% and items between 50% and 75% were also found to be 32.4%, and therefore, consumer goods with over 50% item market concentration rate were 72% of the entire quantity. Second, upon analyzing whether there are differences in index fluctuation rates per item according to the market concentration level of consumer goods and service items, it was found that in the case of consumer goods, the difference between groups for index fluctuation rates per item was very significant for both CR3 and HHI even when fluctuation rates of sales costs compared to shipping cost were controlled. Also, follow-up verification results showed that for CR3 and HHI, the CR3 50% to 75% and HHI 1200 to 2500 groups had significantly higher index fluctuation rates compared to CR3 75% or higher and HHI 2500 or higher, respectively, thus showing that prices increased significantly. According to arithmetic averages, CR3 and HHI both had lowest index fluctuation rates for the highest concentrate groups, and in the case of services as well, CR3 50% or higher and HHI 1200 or higher had lower index fluctuation rates compared to the low-concentration groups of CR3 50% or lower and HHI 1200 or lower. Third, upon categorizing the 33 consumer goods and service evaluation markets into the high-concentration groups (CR3 50% or higher or HHI 1200 or higher) and the low-concentration group (CR3 50% or lower and HHI 1200 or lower) to analyze the 2015 and 2017 Korea Consumer Markets Performance Index, it was found that the 2015 CMPI (index) and four out of five evaluation items and the 2017 KCMPI (index) and all evaluation items had higher averages for the high-concentration group than the low-concentration group. However, the difference between such groups dropped in 2017 compared to 2015, and the Mann-Whitney U test results showed significant differences between the groups in satisfaction and reliability in 2015, while in 2017, they were not significant in both index and all evaluation items in 2017, demonstrating statistically consistent results. Paired sample t-test was conducted to compare the fluctuation of the 2015 and 2017 index and evaluation item scores per concentration level, and it was found that while the high-concentration group did not have significant index difference between the two years, the index in the low-concentration group increased significantly in 2017 compared to 2015. While the low-concentration group had overall similar or slight changes in scores in the two years, it was found that in the high-concentration group, the higher-than-average market lowered and the lower market became higher, thus demonstrating frequent cases in which the evaluation results were completely switched. Fourth, in order to check for differences in the contents of violation of competition laws per market concentration levels of consumer goods and services, the contents of the behavior and the ensuing consumer benefits per market concentration level was analyzed for cases of violation of competition laws from 2011 to 2015 and were ruled between 2011 and 2018 for consumer goods and service items subject to this study. Results showed that high-concentration items with CR3 of 50% or higher had a bigger variety of competition law violations than in the low-concentration items. In particular, all competition-limiting cartels occurred in the highest concentration level of CR3 75% or higher and it was also found that resale price maintaining behavior and unfair cooperative action generally occurred more frequently than in 50% to 75%. In the case of low-concentration items of CR3 50% or lower, there were considerably higher number of business organization prohibited acts violations and unfair trade behavior occurred most frequently in all concentration levels, but was particularly concentrated in some low-concentration items. The conclusions of this study based on the above are as follows. First, it is necessary to recognize that the concentration level of many consumer goods and services often purchased by consumers in everyday life corresponds to market-dominating businesses by law. This can help to better understand phenomena that occur in the market from the context of the market structure and to remind consumers the importance of market monitoring. The authorities related to competition must reinforce monitoring and regulations on consumer goods and services that are directly related to the everyday lives of consumers. Second, as items of groups with the highest market concentration showed the lowest index fluctuation rates on average, the conventional wisdom that prices of high-concentration markets will be raised more was not supported. Such results appear to be attributable to the fact that social monitoring focuses on high-concentration markets and that they include items that have high price-sensitivity or are sensitive to policies or social opinion. Monopolistic prices that are already set high, launch of new products, reflecting asymmetrical prices for fluctuations of raw material prices, etc. are also related to the economic interests of consumers, and therefore, the need to comprehensively consider more various factors when associating price fluctuation rates with consumer welfare for economic interests have been suggested. The mid-concentration group of CR3 50% to 75% and HHI 1200 to 2500 displayed competition-limits as well as high average index fluctuation rates, thus requiring more precise monitoring. Third, results of analyzing the Korea Consumer Markets Performance Index made it possible to assume that in the low-concentration market, the level of consumer directivity was improved considerable compared to the high-concentration market in macroscopic aspects. Meanwhile, high-concentration evaluation markets are subject to monitoring for competition-limiting and therefore, there is a possibility for it to be more sensitive to consumer attitudes or evaluations of consumers on the market. Furthermore, because there are relatively fewer businesses that make up the evaluation item, they exchange corporate behavior and appear to have market structures that are advantageous for making short-term achievements. For evaluation markets that recorded higher-than-average scores in 2015 and lower-than-average scores in 2017, it implies the possibility that the high-concentration market would not have significant consumer directivity improvement if consumer interest is not high. Fourth, because high-concentration markets with CR3 exceeding 75% exhibited relatively high frequency of a bigger variety of competition law violations, concentrated monitoring of the regulatory authorities are urgently needed. In particular, importance is emphasized in the fact that high-concentration markets had bigger impact on markets and consumers compared to the low-concentration market. The CR3 50% to 75% market also had violations occurring based on some competition-limiting like the high-concentration market, and therefore, it is necessary to keep an eye on the corresponding level of competition and market features to check if there are any regulatory vacuums. Lastly, the CR3 50% and below markets have high counts of unfair transactions in certain items due to excessive competition, and therefore, it is judged that stricter and more timely policy intervention by the regulatory authorities are needed for markets with excessive competition. Furthermore, it is necessary to improve market monitoring capacities based on each region so that business organizations made up of individual businesses in each region do not exercise influence that impedes upon consumer welfare in their respective markets. Lastly, the need for monitoring, detection and restricting violations of competition laws for items close to the everyday lives of consumers by the competition authorities over all other policy projects is proposed.제 1 장 서론 1 제 1 절 문제제기 1 제 2 절 연구목적 및 의의 3 제 2 장 이론적 배경 5 제 1 절 시장집중도의 의미와 측정 5 1. 시장구조의 측정 5 2. 시장구조와 시장집중도 6 3. 국내 산업의 시장집중도 측정 8 제 2 절 소비자후생의 개념과 측정 11 1. 소비자후생의 경제학적 개념과 측정 11 2. 소비자후생의 소비자학적 개념과 측정 16 3. 소결 22 제 3 절 시장집중도에 따른 시장특성에 관한 논의 24 1. 시장집중도와 가격 24 2. 시장집중도와 가격 이외 시장 특성 30 제 4 절 시장집중도와 시장 규제 39 1. 경쟁제한적 시장구조 개선 39 2. 행위에 대한 규제 41 제 3 장 연구문제 및 연구방법 49 제 1 절 연구문제 49 1. 연구문제 49 2. 조작적 정의 50 제 2 절 연구방법 51 1. 소비재와 서비스의 시장집중도 분석 51 2. 소비재와 서비스의 시장집중도에 따른 가격변동률 분석 57 3. 시장집중도 수준에 따른 소비자시장성과지수 분석 60 4. 시장집중도 수준에 따른 공정거래법 위반행위 분석 67 제 4 장 연구의 결과 및 분석 70 제 1 절 시장집중도 수준 분석 70 1. 시장집중도의 평균 비교 70 2. 시장집중도의 수준별 분포 72 3. 시장집중도의 수준별 산업 및 품목 분석 74 제 2 절 시장집중도와 가격변동률 78 1. 소비재의 시장집중도와 가격변동률 78 2. 서비스의 시장집중도와 가격변동률 84 3. 소결 86 제 3 절 시장집중도와 소비자시장성과지수 87 1. 시장집중도와 2015년 소비자시장성과지수 87 2. 시장집중도와 2017년 소비자시장성과지수 91 3. 시장집중도와 2015년2017년 소비자시장성과지수 비교 95 4. 소결 99 제 4 절 시장집중도와 경쟁법 위반행위 100 1. 경쟁제한적 기업결합: 시장집중도 수준별 소비자후생 100 2. 부당한 공동행위: 시장집중도 수준별 소비자후생 102 3. 불공정거래행위: 시장집중도 수준별 소비자후생 105 4. 사업자단체 금지행위: 시장집중도 수준별 소비자후생 109 5 재판매가격 유지행위: 시장집중도 수준별 소비자후생 111 6. 소결 113 제 5 장 결론 및 제언 114 제 1 절 요약 및 결론 114 제 2 절 제언 124 참고문헌 127 부록 142 Abstract 152Docto

E-cadherin expression changes and skin wound healing efficacy in human umbilical cord blood-derived mesenchymal stem cells treated with high glucose

학위논문 (박사)-- 서울대학교 대학원 : 농업생명과학대학 동물자원과학과, 2018. 8. 이창규.Glucose plays an important role in stem cell fate determination and its behavior. Stem cell fate is regulated by genes involved in differentiation, proliferation, and migration. Previous investigators have suggested that oxidative stress, especially reactive oxygen species (ROS), increases stem cell migration and the increase of ROS may destroy the homeostasis of the cells, and subsequently serious damage in the cells. High glucose is the cause of excess ROS that leads to diabetic complications. 17β-estradiol (E2) is an important regulator of energy homeostasis and glucose metabolism, so that it should be considered a suitable target of E2 for preventing or treating metabolic disorders. Diabetes is closely related to oxidative stress and the risk of diabetes is high in patients who are deficient in E2. Thus, E2 has protective roles against oxidative stress exposure which leads to mitochondrial dysfunction and damage. However, it remains unclear how glucose contributes to the precise molecular mechanism for producing ROS in the stem cell and E2 evokes protective antioxidant mechanisms. Therefore, present study aimed to investigate 1) the effect of high glucose on stem cell migration and its related signaling pathways, 2) the role of E2 in glucose-mediated mitochondrial ROS (mtROS) level in human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs), and 3) the effect of hUCB-MSC transplantation on mouse skin wound healing by E2 in ovariectomized (OVX) diabetic mice in vivo. First, I investigated the effect of high glucose on regulation of hUCB-MSC migration. High glucose treatment (D-glucose) induced hUCB-MSC migration, expression of cleaved Notch, Snail and enhancer of zeste homolog2 (EZH2), but repressed epithelial cadherin (E-cadherin) expression. E-cadherin repression was regulated by high glucose through Snail and EZH2 upregulation, and Snail was modulated in parallel with EZH2 in hUCB-MSCs. Next, I demonstrated that high glucose enhanced ROS, which activates either c-Jun N-terminal kinase (JNK) or phosphatidylinositol-3-kinses (PI3K)/protein kinase B (Akt) signaling. High glucose-induced JNK activation elicit the cleavage of Notch protein through γ–secretase activation, following Notch intracellular domain (NICD) translocation into the nucleus. In the nucleus, Snail interacted with polycomb repressive complex 2 (PRC2) components by high glucose. And then EZH2, one of the major component of PRC2, and Snail bound with E-box of the E-cadherin promoter by high glucose, which in turn causes E-cadherin repression. Taken together, these results suggest that high glucose-induced ROS production increases the migration of hUCB-MSCs through E-cadherin repression via EZH2 and Snail upregulation. Next, I investigated the role of E2 on mtROS-mediated autophagic cell death by high glucose in hUCB-MSCs. High glucose increased mtROS to upregulate Beclin1 and LC-II expression, leading to decreased cell viability. In contrast, E2 treatment significantly decreased high glucose-induced mtROS levels and subsequently restored cell viability, suggesting that E2 serves as a strong antioxidant. I found that treatment of both E2 and high glucose promoted ERα translocation into the nucleus leading to increased Nrf2 in the nucleus. However, high glucose produced mtROS via downregulating Nrf2 nuclear translocation. This subsequently culminated in Sirtuin3 (Sirt3) downregulation and manganese superoxide dismutase (MnSOD) acetylation. The increased nuclear translocation of Nrf2 triggered upregulation of Sirt3 expression and activated MnSODCHAPTER I LITERATURE REVIEW 1 CHAPTER II Regulation of migration in hUCB-MSCs by high glucose-induced ROS via Snail/EZH2/E-cadherin pathway 26 1. INTRODUCTION 27 2. MATERIALS AND METHODS 31 3. RESULTS 46 4. DISCUSSION 92 CHAPTER III 17β-Estradiol enhances hUCB-MSCs-induced wound healing in the ovariectomized diabetic mouse model through estrogen receptorα-dependent MnSOD activation via Nrf2 and Sirt3 upregulation 101 1. INTRODUCTION 102 2. MATERIALSAMD METHODS 106 3. RESULTS 124 4. DISCUSSION 172 CHAPTER IV GENERAL CONCLUSION 180 REFERENCES 183 ABSTRACT IN KOREAN 212Docto

Renal Manifestations and Imaging Studies of Kawasaki Disease

Purpose: The aim of this study was to verify renal inflammation following Kawasaki disease (KD) using single photon emission computed tomography along with Technetium-99m dimercaptosuccinic acid scintigraphy (DMSA renal SPECT). Methods: From March 2011 to October 2011, 15 patients diagnosed with KD at the National Health Insurance System Ilsan Hospital were enrolled in the study. All patients underwent DMSA renal SPECT to evaluate renal involvement during the acute phase of KD. Urine β2-microglobulin (β2-MG), a marker of renal proximal tubular dysfunction, was also measured to assess renal damage. Results : All 15 patients had normal renal function test results. However, microscopic hematuria and pyuria were observed in 13% and 33% of the patients, respectively. Moreover, urine β2-MG was elevated in 46% of the patients. In addition, patients were divided into two groups based on β2-MG level: those with an increased β2-MG level, and those with a normal β2-MG level. No significant differences were found between these two groups in clinical characteristics, laboratory, sonography, and echocardiography findings. All patients' DMSA renal SPECT scans were normal. Conclusion : Our study showed that mild abnormalities in the urinalysis and elevated urine β2-MG were the only findings of renal involvement in KD. However, no aggressive renal manifestations were detected on DMSA renal SPECT.ope

Syndrome of inappropriate antidiuretic hormone secretion and cerebral/renal salt wasting syndrome: similarities and differences.

Hyponatremia (sodium levels of <135 mEq/L) is one of the most common electrolyte imbalances in clinical practice, especially in patients with neurologic diseases. Hyponatremia can cause cerebral edema and brain herniation; therefore, prompt diagnosis and proper treatment is important in preventing morbidity and mortality. Among various causes of hyponatremia, diagnosing syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral/renal salt wasting syndrome (C/RSW) is difficult due to many similarities. SIADH is caused by excess of renal water reabsorption through inappropriate antidiuretic hormone secretion, and fluid restriction is the treatment of choice. On the other hand, C/RSW is caused by natriuresis, which is followed by volume depletion and negative sodium balance and replacement of water and sodium is the mainstay of treatment. Determinating volume status in hyponatremic patients is the key point in differential between SIADH and C/RSW. However, in most situations, differential diagnosis of these two diseases is difficult because they overlap in many clinical and laboratory aspects, especially to assess differences in volume status of these patients. Although distinction between the SIADH and C/RSW is difficult, improvement of hypouricemia and an increased fractional excretion of uric acid after the correction of hyponatremia in SIADH, not in C/RSW, may be one of the helpful points in discriminating the two diseases. In this review, we compare these two diseases regarding the pathophysiologic mechanisms, diagnosis, and therapeutic point of view.ope

Clinical application of a phenotype-based NGS panel for differential diagnosis of inherited kidney disease and beyond

Understanding the genetic causes of kidney disease is essential for accurate diagnosis and could lead to improved therapeutic strategies and prognosis. To accurately and promptly identify the genetic background of kidney diseases, we applied a targeted next-generation sequencing gene panel including 203 genes associated with kidney disease, as well as diseases originating in other organs with mimicking symptoms of kidney disease, to analyze 51 patients with nonspecific nephrogenic symptoms, followed by validation of its efficacy as a diagnostic tool. We simultaneously screened for copy number variants (CNVs) in each patient to obtain a higher diagnostic yield (molecular diagnostic rate: 39.2%). Notably, one patient suspected of having Bartter syndrome presented with chloride-secreting diarrhea attributable to homozygous SLC26A3 variants. Additionally, in eight patients, NGS confirmed the genetic causes of undefined kidney diseases (8/20, 40%), and initial clinical impression and molecular diagnosis were matched in 11 patients (11/20, 55%). Moreover, we found seven novel pathogenic/likely pathogenic variants in PKD1, PKHD1, COL4A3, and SLC12A1 genes, with a possible pathogenic variant in COL4A3 (c.1229G>A) identified in two unrelated patients. These results suggest that targeted NGS-panel testing performed with CNV analysis might be advantageous for noninvasive and comprehensive diagnosis of suspected genetic kidney diseases.ope

Noninfectious Complications of Peritoneal Dialysis in Korean Children: A 26-Year Single-Center Study

PURPOSE: The aim of this study was to investigate noninfectious complications of peritoneal dialysis (PD), including mechanical and metabolic complications, at a single center in Korea. MATERIALS AND METHODS: We analyzed data from 60 PD patients aged ≤18 years (40 boys and 20 girls) during the period between 1986 and 2012. The collected data included gender, age, causes of PD, incidence of noninfectious complications, and treatment for the complications. RESULTS: The mean duration of PD therapy was 28.7±42.1 months (range 1-240 months). The most common cause of end-stage renal disease was glomerular disease (43.3%). There were no statistically significant differences between patients with and without mechanical complications regarding gender, age at the start of PD, and total duration of PD. Outflow failure was the most common catheter-related complication (14.3%), followed by leakage (10.0%) and hernia (8.6%). Metabolic complications, such as hyperglycemia and hypokalemia, were observed in three of 16 patients. The frequency of noninfectious complications of PD in our study was comparable with those in previous pediatric studies. PD was switched to hemodialysis (HD) in only three patients. CONCLUSION: Our results indicate that noninfectious complications of PD are common, though they hardly lead to catheter removal or HD in pediatric patients on PD.ope

Outcomes of Hemodialysis in Children: A 35-Year Experience at Severance Hospital

PURPOSE: The aim of this study was to analyze the results of children treated with hemodialysis (HD) at Severance Hospital over 35 years in terms of incidence, etiologies, characteristics, complications, and clinical outcomes. MATERIALS AND METHODS: We analyzed 46 children admitted to Severance Hospital who had undergone HD between January 1979 and December 2013. RESULTS: The main etiologies of the 23 end-stage renal disease (ESRD) patients who had received HD were chronic glomerulonephritis (7 patients, 30.4%) and congenital anomalies of the kidney and urinary tract (7 patients, 30.4%), whereas the etiology of the 23 acute kidney injury (AKI) patients was hemolytic uremic syndrome (6 patients, 26.1%). Compared with ESRD patients, hemocatheter placement in the femoral vein was preferred over the subclavian or internal jugular vein in the AKI patients (p=0.012). The most common complication was catheter related complication (10 patients, 21.7%). The site of hemocatheter insertion was not related to the frequency of oozing. Placing the hemocatheter in the femoral vein resulted in significantly more events of catheter obstruction than insertion in the internal jugular vein or the subclavian vein (p=0.001). Disequilibrium syndrome occurred more frequently in older patients (p=0.004), as well as patients with a greater body weight (p=0.008) and a higher systolic and diastolic blood pressure before HD (systolic: p=0.021; diastolic: p=0.040). CONCLUSION: Based on the 35 years of experience in our center, HD can be sufficiently and safely carried out even in children without significant complications.ope

A Case of Atypical Thrombotic Microangiopathy

We report the case of a 14-year-old girl, diagnosed with atypical thrombotic microangiopathy (TMA). The patient presented with persistent fever, nausea, and newly developed peripheral edema. Her laboratory findings indicated chronic anemia with no evidence of hemolysis, thrombocytopenia, or elevated serum creatinine level. A few days after hospitalization, acute renal failure and fever worsened, and proteinuria developed. On day 40 of hospitalization, she experienced a generalized tonic seizure for 5 min, accompanied by renal hypertension. Brain magnetic resonance imaging revealed posterior reversible leukoencephalopathy syndrome. After steroid pulse therapy, a renal biopsy was performed because of delayed recovery from thrombocytopenia. The biopsy findings showed features of thrombotic microangiopathic hemolysis with fibrinoid change restricted. Current diagnostic criteria for TMA have focused on thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, and diagnosis is based on the clinical presentation and etiology, with the consequence that idiopathic and atypical forms of TMA can be overlooked. Developing effective tools to diagnose TMA, such as studying levels of ADAMTS13 or testing for abnormalities in the complement system, will be the first step to improving patient outcomes.ope

Genetic diagnosis of inborn errors of immunity using clinical exome sequencing

Inborn errors of immunity (IEI) include a variety of heterogeneous genetic disorders in which defects in the immune system lead to an increased susceptibility to infections and other complications. Accurate, prompt diagnosis of IEI is crucial for treatment plan and prognostication. In this study, clinical utility of clinical exome sequencing (CES) for diagnosis of IEI was evaluated. For 37 Korean patients with suspected symptoms, signs, or laboratory abnormalities associated with IEI, CES that covers 4,894 genes including genes related to IEI was performed. Their clinical diagnosis, clinical characteristics, family history of infection, and laboratory results, as well as detected variants, were reviewed. With CES, genetic diagnosis of IEI was made in 15 out of 37 patients (40.5%). Seventeen pathogenic variants were detected from IEI-related genes, BTK, UNC13D, STAT3, IL2RG, IL10RA, NRAS, SH2D1A, GATA2, TET2, PRF1, and UBA1, of which four variants were previously unreported. Among them, somatic causative variants were identified from GATA2, TET2, and UBA4. In addition, we identified two patients incidentally diagnosed IEI by CES, which was performed to diagnose other diseases of patients with unrecognized IEI. Taken together, these results demonstrate the utility of CES for the diagnosis of IEI, which contributes to accurate diagnosis and proper treatments.ope

서울 야간경관의 형성과 변화과정에 관한 연구

학위논문(석사)--서울대학교 대학원 :생태조경학과,2004.Maste